WorldWideScience

Sample records for dust stream collection

  1. Mineralogy of Interplanetary Dust Particles from the Comet Giacobini-Zinner Dust Stream Collections

    Science.gov (United States)

    Nakamura-Messenger, K.; Messenger, S.; Westphal, A. J.; Palma, R. L.

    2015-01-01

    The Draconoid meteor shower, originating from comet 21P/Giacobini-Zinner, is a low-velocity Earth-crossing dust stream that had a peak anticipated flux on Oct. 8, 2012. In response to this prediction, NASA performed dedicated stratospheric dust collections to target interplanetary dust particles (IDPs) from this comet stream on Oct 15-17, 2012 [3]. Twelve dust particles from this targeted collection were allocated to our coordinated analysis team for studies of noble gas (Univ. Minnesota, Minnesota State Univ.), SXRF and Fe-XANES (SSL Berkeley) and mineralogy/isotopes (JSC). Here we report a mineralogical study of 3 IDPs from the Draconoid collection..

  2. Io as a source of the jovian dust streams

    Science.gov (United States)

    Graps; Grun; Svedhem; Kruger; Horanyl; Heck; Lammers

    2000-05-04

    Streams of dust emerging from the direction of Jupiter were discovered in 1992 during the flyby of the Ulysses spacecraft, but their precise origin within the jovian system remained unclear. Further data collected by the Galileo spacecraft, which has been orbiting Jupiter since December 1995, identified the possible sources of dust as Jupiter's main ring, its gossamer ring, comet Shoemaker-Levy 9 (ref. 8) and Io. All but Jupiter's gossamer ring and Io have since been ruled out. Here we find that the dominant source of the jovian dust streams is Io, on the basis of periodicities in the dust impact signal. Io's volcanoes, rather than impact ejecta, are the dust sources.

  3. Jovian dust streams: A monitor of Io's volcanic plume activity

    Science.gov (United States)

    Kruger, H.; Geissler, P.; Horanyi, M.; Graps, A.L.; Kempf, S.; Srama, R.; Moragas-Klostermeyer, G.; Moissl, R.; Johnson, T.V.; Grun, E.

    2003-01-01

    Streams of high speed dust particles originate from Jupiter's moon Io. After release from Io, the particles collect electric charges in the Io plasma torus, gain energy from the co-rotating electric field of Jupiter's magnetosphere, and leave the Jovian system into interplanetary space with escape speeds over 200 km s-1. The Galileo spacecraft has continuously monitored the dust streams during 34 revolutions about Jupiter between 1996 and 2002. The observed dust fluxes exhibit large orbit-to-orbit variability due to systematic and stochastic changes. After removal of the systematic variations, the total dust emission rate of Io has been calculated. It varies between 10-3 and 10 kg s-1, and is typically in the range of 0.1 to 1 kg s-1. We compare the dust emission rate with other markers of volcanic activity on Io like large-area surface changes caused by volcanic deposits and sightings of volcanic plumes. Copyright 2003 by the American Geophysical Union.

  4. Electrospray Collection of Lunar Dust

    Science.gov (United States)

    Dziekan, Michael

    2012-01-01

    A report describes ElectroSpray Ionization based Electrostatic Precipitation (ESIEP) for collecting lunar dust particles. While some HEPA filtration processes may remove a higher fraction (>99.9 percent) of the particles, the high efficiency may not be appropriate from an overall system standpoint, especially in light of the relatively large power requirement that such systems demand. The new electrospray particle capture technology is described as a variant of electrostatic precipitation that eliminates the current drawbacks of electrostatic precipitation. The new approach replaces corona prone field with a mist of highly charged micro-droplets generated by electrospray ionization (ESI) as the mechanism by which incoming particles are attracted and captured. In electrospray, a miniscule flow rate (microliters/minute) of liquid (typically water and a small amount of salt to enhance conductivity) is fed from the tip of a needle held at a high voltage potential relative to an opposite counter electrode. At sufficient field strength, a sharp liquid meniscus forms , which emits a jet of highly charged droplets that drift through the surrounding gas and are collected on the walls of a conductive tube. Particles in the gas have a high probability of contact with the droplets either by adhering to the droplets or otherwise acquiring a high level of charge, causing them to be captured on the collecting electrode as well. The spray acts as a filtration material that is continuously introduced and removed from the gas flow, and thus can never become clogged.

  5. Electromagnetically Interacting Dust Streams During Ulysses' Second Jupiter Encounter

    International Nuclear Information System (INIS)

    Krueger, H.; Forsyth, R.J.; Graps, A.L.; Gruen, E.

    2005-01-01

    The Jupiter system is a source of collimated burst-like streams of electrically charged 10-nm dust particles. In 2004 the Ulysses spacecraft had its second flyby at Jupiter and from late 2002 to early 2005 it measured a total of 24 dust streams between 0.8 and 3.4 AU from the planet. The grains show strong coupling to the interplanetary magnetic field: their impact directions correlate with the orientation and strength of the interplanetary magnetic field vector (namely its tangential and radial components) and they occur at 26 day intervals, closely matching the solar rotation period. Ulysses measured the dust streams over a large range in jovian latitude (+75 deg. to -35 deg.). Enhanced dust emission was measured along the jovian equator

  6. High-velocity streams of dust originating from Saturn.

    Science.gov (United States)

    Kempf, Sascha; Srama, Ralf; Horányi, Mihaly; Burton, Marcia; Helfert, Stefan; Moragas-Klostermeyer, Georg; Roy, Mou; Grün, Eberhard

    2005-01-20

    High-velocity submicrometre-sized dust particles expelled from the jovian system have been identified by dust detectors on board several spacecraft. On the basis of periodicities in the dust impact rate, Jupiter's moon Io was found to be the dominant source of the streams. The grains become positively charged within the plasma environment of Jupiter's magnetosphere, and gain energy from its co-rotational electric field. Outside the magnetosphere, the dynamics of the grains are governed by the interaction with the interplanetary magnetic field that eventually forms the streams. A similar process was suggested for Saturn. Here we report the discovery by the Cassini spacecraft of bursts of high-velocity dust particles (> or = 100 km s(-1)) within approximately 70 million kilometres of Saturn. Most of the particles detected at large distances appear to originate from the outskirts of Saturn's outermost main ring. All bursts of dust impacts detected within 150 Saturn radii are characterized by impact directions markedly different from those measured between the bursts, and they clearly coincide with the spacecraft's traversals through streams of compressed solar wind.

  7. The Interstellar Gas Dust Streams and Seeds of Life

    Science.gov (United States)

    Oleg, Khavroshkin; Vladislav, Tsyplakov

    Gas dust Streams from Double Stars & Lunar Seismicity. The time series of seismic events were generated as follows: on the ordinate axis the peak amplitudes of events in standard units, on abscissa axis - seismogram durations of the same moonquakes and subsequent time intervals between them were used. Spectrum of the series disclosed time picks on hidden cosmological periodicities of lunar seismicity. A part of results (picks) presents orbital periods of double stars nearest to the Solar system. The explanation of that results is existing gas-dust streams from binary stars systems and interacting of it with lunar surface. Information content of the Nakamura`s Catalog of moonquakes is very rich: from solar-earth tides to clustering among the meteoroid streams [1, 2]. The histograms from meteoroid impacts seismic data revealed the seismic wave responses of the Moon to solar oscillations and the action on the lunar surface by dust-gas plasma of meteoroid streams [3]. The time series of seismic events were generated as follows: on an axis of ordinates - the peak amplitudes of events in standard units, on an abscissa - seismogram durations of the same moonquakes and subsequent time intervals between them were put aside [4]. Spectrum of the series of meteoroid streams seismicity disclosed time picks on orbital periods some planets and their satellites and solar oscillations [4, 5]. The research of peculiarities of histogram envelopes [3] and comparative common analysis solar bursts data and mass meteoroid distribution are confirmed [3, 4] and revealed Forbush`s effect for gas-dust plasma [6]. Hidden astrophysical periodicities of lunar seismicity were obtained early from an analysis of time series [7] which were similarity to series [4]. The path of results of [7] is presented in the Table where picks presents orbital periods of double stars nearest to the Solar system. Hypothesis for explanation of the Table results is existing gas-dust streams from binary stars near

  8. Interstellar dust. Evidence for interstellar origin of seven dust particles collected by the Stardust spacecraft.

    Science.gov (United States)

    Westphal, Andrew J; Stroud, Rhonda M; Bechtel, Hans A; Brenker, Frank E; Butterworth, Anna L; Flynn, George J; Frank, David R; Gainsforth, Zack; Hillier, Jon K; Postberg, Frank; Simionovici, Alexandre S; Sterken, Veerle J; Nittler, Larry R; Allen, Carlton; Anderson, David; Ansari, Asna; Bajt, Saša; Bastien, Ron K; Bassim, Nabil; Bridges, John; Brownlee, Donald E; Burchell, Mark; Burghammer, Manfred; Changela, Hitesh; Cloetens, Peter; Davis, Andrew M; Doll, Ryan; Floss, Christine; Grün, Eberhard; Heck, Philipp R; Hoppe, Peter; Hudson, Bruce; Huth, Joachim; Kearsley, Anton; King, Ashley J; Lai, Barry; Leitner, Jan; Lemelle, Laurence; Leonard, Ariel; Leroux, Hugues; Lettieri, Robert; Marchant, William; Ogliore, Ryan; Ong, Wei Jia; Price, Mark C; Sandford, Scott A; Sans Tresseras, Juan-Angel; Schmitz, Sylvia; Schoonjans, Tom; Schreiber, Kate; Silversmit, Geert; Solé, Vicente A; Srama, Ralf; Stadermann, Frank; Stephan, Thomas; Stodolna, Julien; Sutton, Stephen; Trieloff, Mario; Tsou, Peter; Tyliszczak, Tolek; Vekemans, Bart; Vincze, Laszlo; Von Korff, Joshua; Wordsworth, Naomi; Zevin, Daniel; Zolensky, Michael E

    2014-08-15

    Seven particles captured by the Stardust Interstellar Dust Collector and returned to Earth for laboratory analysis have features consistent with an origin in the contemporary interstellar dust stream. More than 50 spacecraft debris particles were also identified. The interstellar dust candidates are readily distinguished from debris impacts on the basis of elemental composition and/or impact trajectory. The seven candidate interstellar particles are diverse in elemental composition, crystal structure, and size. The presence of crystalline grains and multiple iron-bearing phases, including sulfide, in some particles indicates that individual interstellar particles diverge from any one representative model of interstellar dust inferred from astronomical observations and theory. Copyright © 2014, American Association for the Advancement of Science.

  9. The Impact of Meteoroid Streams on the Lunar Atmosphere and Dust Environment During the LADEE Mission

    Science.gov (United States)

    Stubbs, T. J.; Glenar, D. A.; Wang, Y.; Hermalyn, B.; Sarantos, M.; Colaprete, A.; Elphic, R. C.

    2015-01-01

    The scientific objectives of the Lunar Atmosphere and Dust Environment Explorer (LADEE) mission are: (1) determine the composition of the lunar atmosphere, investigate processes controlling distribution and variability - sources, sinks, and surface interactions; and (2) characterize the lunar exospheric dust environment, measure spatial and temporal variability, and influences on the lunar atmosphere. Impacts on the lunar surface from meteoroid streams encountered by the Earth-Moon system are anticipated to result in enhancements in the both the lunar atmosphere and dust environment. Here we describe the annual meteoroid streams expected to be incident at the Moon during the LADEE mission, and their anticipated effects on the lunar environment.

  10. Value Stream Mapping: Foam Collection and Processing.

    Energy Technology Data Exchange (ETDEWEB)

    Sorensen, Christian [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-07-01

    The effort to collect and process foam for the purpose of recycling performed by the Material Sustainability and Pollution Prevention (MSP2) team at Sandia National Laboratories is an incredible one, but in order to make it run more efficiently it needed some tweaking. This project started in June of 2015. We used the Value Stream Mapping process to allow us to look at the current state of the foam collection and processing operation. We then thought of all the possible ways the process could be improved. Soon after that we discussed which of the "dreams" were feasible. And finally, we assigned action items to members of the team so as to ensure that the improvements actually occur. These improvements will then, due to varying factors, continue to occur over the next couple years.

  11. Creating a streaming video collection for your library

    CERN Document Server

    Duncan, Cheryl J

    2014-01-01

    Creating a Streaming Video Collection for Your Library covers the main processes associated with streaming video, from licensing to access and evaluation, and will serve as a key reference and source of best practices for libraries adding streaming video titles to their collections.

  12. Airborne sand and dust soiling of solar collecting mirrors

    Science.gov (United States)

    Sansom, Christopher; Almond, Heather; King, Peter; Endaya, Essam; Bouaichaoui, Sofiane

    2017-06-01

    The reflectance of solar collecting mirrors can be significantly reduced by sand and dust soiling, particularly in arid environments. Larger airborne sand and dust particles can also cause damage by erosion, again reducing reflectance. This work describes investigations of the airborne particle size, shape, and composition in three arid locations that are considered suitable for CSP plants, namely in Iran, Libya, and Algeria. Sand and dust has been collected at heights between 0.5 to 2.0m by a variety of techniques, but are shown not to be representative of the particle size found either in ground dust and sand, or on the solar collecting mirror facets themselves. The possible reasons for this are proposed, most notably that larger particles may rebound from the mirror surface. The implications for mirror cleaning and collector facet erosion are discussed.

  13. Formation of dust maximums in aerosol stream in a dispersion medium

    International Nuclear Information System (INIS)

    Neklyudov, I.M.; Ledenev, O.P.; Fedorova, L.I.; Poltinin, P.Ya.

    2010-01-01

    Spatial-temporal distribution of the fine dust coal fraction accumulated in the process of air-dust intermixture aerosol flow through the horizontally positioned air filter consisting of the big granules of absorber is researched. Aerodynamic resistance of the horizontally positioned air filters at long term dust trust happens to be significantly lower in comparison with the vertically positioned air filters in industrial applications at NPP's over the years. It is assumed that this phenomena appears, because the directions of the dust masses capture force in airflow and the gravitation force are orthogonal, hence the fine dust coal particles are dislocated by the gravitation force from the volume of main air stream localization within the filter.

  14. Dust as a collection media for contaminant source attribution.

    Science.gov (United States)

    Favela, Kristin Herrmann; Bohmann, Jonathan A; Williamson, William S

    2012-04-10

    Dust was investigated for its ability to retain source attribution profiles (SAPs) after chemical exposure. Three distinct sources of the organophosphate pesticide acephate were investigated as a proof-of-concept model. In addition, attribution profiles were created and tested using compounds related to chemical warfare agents (CWAs), specifically VX and G-series agents: O-ethyl methylphosphonothioate (EMPTA), N,N-diisopropylmethylamine (DIPMA), N,N-diisopropylethylamine (DIEA), diisopropylamine (DIPA), diethyl aniline (DEA), diethyl ethyl phosphonate (DEEP), trimethyl phosphite (TMP), dimethyl hydrogen phosphite (DMHP), diethyl hydrogen phosphite (DEHP), triethyl phosphate (TEP), ethyl methylphosphonate (EMPA), and diisopropyl methylphosphonate (DIMP). Dust was collected from a storage shed, aliquots deposited on carpet and loaded with distinct chemical profiles using an exposure chamber and aerosolizer. After a given period of time (1h, 24h, or 72 h), the dust was extracted and its SAP analyzed by gas chromatography-mass spectrometry (GC-MS) and/or liquid chromatography-tandem mass spectrometry (LC-MS/MS). Principal components analysis (PCA) was used to determine the association of dust exposed to the same and different chemical sources. PCA results demonstrate that dust samples exposed to distinct chemical sources are clearly differentiated from one another across all collection times. Furthermore, dust aliquots exposed to the same source can be clearly associated with one another across all collection times. When the CWA-related compounds were subjected to elevated temperature (90°C) conditions, it was found that the signature was stable at the 1h and 24h collections. At 72 h and elevated temperature, larger deviations from the control were observed for some compounds. Elevated pH (10) affected the profile to a lesser degree than elevated temperature. Overall, dust is found to be an effective media for the in situ collection of source attribution profiles

  15. Dust collection and removal - NFP-collector

    International Nuclear Information System (INIS)

    Sato, N.

    2005-01-01

    A short description of an NFP-Collector (Negatively Charged Fine-Particle Collector) proposed for the collection and removal of fine particles in dusty plasmas is presented. The effects of the Collector on silane plasma, in which dusty fine particles are formed, are presented

  16. Abundance and Community Structure of Bacteria on Asian Dust Particles Collected in Beijing, China, during the Asian Dust Season.

    Science.gov (United States)

    Yamaguchi, Nobuyasu; Baba, Takashi; Ichijo, Tomoaki; Himezawa, Yuka; Enoki, Kanami; Saraya, Makoto; Li, Pin-Fang; Nasu, Masao

    2016-01-01

    Approximately 180 t/km(2) of Asian dust particles are estimated to fall annually on Beijing, China, and there is significant concern about the influence of microbes transported by Asian dust events on human health and downwind ecosystems. In this study, we collected Asian dust particles in Beijing, and analyzed the bacterial communities on these particles by culture-independent methods. Bacterial cells on Asian dust particles were visualized first by laser scanning microscopy, which demonstrated that Asian dust particles carry bacterial cells to Beijing. Bacterial abundance, as determined by quantitative polymerase chain reaction (PCR), was 10(8) to 10(9) cells/g, a value about 10 times higher than that in Asian dust source soils. Inter-seasonal variability of bacterial community structures among Asian dust samples, as compared by terminal restriction fragment length polymorphism (T-RFLP), was low during the Asian dust season. Several viable bacteria, including intestinal bacteria, were found in Asian dust samples by denaturing gradient gel electrophoresis (DGGE). Clone library analysis targeting 16S ribosomal RNA (rRNA) gene sequences demonstrated that bacterial phylogenetic diversity was high in the dust samples, and most of these were environmental bacteria distributed in soil and air. The dominant species in the clone library was Segetibacter aerophilus (Bacteroidetes), which was first isolated from an Asian dust sample collected in Korea. Our results also indicate the possibility of a change in the bacterial community structure during transportation and increases in desiccation-tolerant bacteria such as Firmicutes.

  17. Size distribution and diffuse pollution impacts of PAHs in street dust in urban streams in the Yangtze River Delta.

    Science.gov (United States)

    Zhao, Hongtao; Yin, Chengqing; Chen, Meixue; Wang, Weidong; Jefferies, Chris; Shan, Baoqing

    2009-01-01

    Particles of dust washed off streets by stormwater are an important pathway of polyaromatic hydrocarbons (PAHs) into urban streams. This article presented a comprehensive assessment of the size distribution of PAHs in street dust particles, the potential risks of the particles in urban streams, and the sources and sinks of PAHs in the stream network. This assessment was based on measurements of 16 PAHs from the USEPA priority list in street dust particles and river sediments in Xincheng, China. The content of total PAHs ranged from 1629 to 8986 microg/kg in street dust particles, where smaller particles have a higher concentrations. Approximately 55% of the total PAHs were associated with particles less than 250 microm which accounted for 40% of the total mass of street dust. The PAH quantities increased from 2.41 to 46.86 microg/m2 in the sequence of new residential, rising through main roads, old town residential, commercial and industrial areas. The sediments in stream reaches in town were found to be sinks for street dust particle PAHs. The research findings suggested that particle size, land use and the hydrological conditions in the stream network were the factors which most influenced the total loads of PAH in the receiving water bodies.

  18. From Dust Grains to Planetesimals: The Importance of the Streaming Instability in Protoplanetary Disks

    Science.gov (United States)

    Simon, Jacob B.; Armitage, Philip J.; Youdin, Andrew N.; Li, Rixin

    2016-01-01

    Planetesimals are the precursors to planets, and understanding their formation is an essential step towards developing a complete theory of planet formation. For small solid particles (e.g., dust grains) to coagulate into planetesimals, however, requires that these particles grow beyond centimeter sizes; with traditional coagulation physics, this is very difficult. The streaming instability, which is a clumping process akin to the pile-up of cars in a traffic jam, generates sufficiently high solid densities that the mutual gravity between the clumped particles eventually causes their collapse towards planetesimal mass and size scales. Exploring this transition from dust grains to planetesimals is still in its infancy but is extremely important if we want to understand the basics of planet formation. Here, I present a series of high resolution, first principles numerical simulations of protoplanetary disk gas and dust to study the clumping of particles via the streaming instability and the subsequent collapse towards planetesimals. These simulations have been employed to characterize the planetesimal population as a function of radius in protoplanetary disks. The results of these simulations will be crucial for planet formation models to correctly explain the formation and configuration of solar systems.

  19. Ion-streaming induced order transition in three-dimensional dust clusters

    International Nuclear Information System (INIS)

    Ludwig, Patrick; Kählert, Hanno; Bonitz, Michael

    2012-01-01

    Dust dynamics simulations utilizing a dynamical screening approach are performed to study the effect of ion-streaming on the self-organized structures in a three-dimensional spherically confined complex (dusty) plasma. Varying the Mach number M, the ratio of ion drift velocity to the sound velocity, the simulations reproduce the experimentally observed cluster configurations in the two limiting cases: at M = 0 strongly correlated crystalline structures consisting of nested spherical shells (Yukawa balls) and, for M ⩾ 1, flow-aligned dust chains, respectively. In addition, our simulations reveal a discontinuous transition between these two limits. It is found that already a moderate ion drift velocity (M ≈ 0.1 for the plasma conditions considered here) destabilizes the highly ordered Yukawa balls and initiates an abrupt melting transition. The critical value of M is found to be independent of the cluster size. (paper)

  20. Seasonal provenance changes in present-day Saharan dust collected in and off Mauritania

    Directory of Open Access Journals (Sweden)

    C. A. Friese

    2017-08-01

    Full Text Available Saharan dust has a crucial influence on the earth climate system and its emission, transport and deposition are intimately related to, e.g., wind speed, precipitation, temperature and vegetation cover. The alteration in the physical and chemical properties of Saharan dust due to environmental changes is often used to reconstruct the climate of the past. However, to better interpret possible climate changes the dust source regions need to be known. By analysing the mineralogical composition of transported or deposited dust, potential dust source areas can be inferred. Summer dust transport off northwest Africa occurs in the Saharan air layer (SAL. In continental dust source areas, dust is also transported in the SAL; however, the predominant dust input occurs from nearby dust sources with the low-level trade winds. Hence, the source regions and related mineralogical tracers differ with season and sampling location. To test this, dust collected in traps onshore and in oceanic sediment traps off Mauritania during 2013 to 2015 was analysed. Meteorological data, particle-size distributions, back-trajectory and mineralogical analyses were compared to derive the dust provenance and dispersal. For the onshore dust samples, the source regions varied according to the seasonal changes in trade-wind direction. Gibbsite and dolomite indicated a Western Saharan and local source during summer, while chlorite, serpentine and rutile indicated a source in Mauritania and Mali during winter. In contrast, for the samples that were collected offshore, dust sources varied according to the seasonal change in the dust transporting air layer. In summer, dust was transported in the SAL from Mauritania, Mali and Libya as indicated by ferroglaucophane and zeolite. In winter, dust was transported with the trades from Western Sahara as indicated by, e.g., fluellite.

  1. Seasonal provenance changes in present-day Saharan dust collected in and off Mauritania

    Science.gov (United States)

    Friese, Carmen A.; van Hateren, Johannes A.; Vogt, Christoph; Fischer, Gerhard; Stuut, Jan-Berend W.

    2017-08-01

    Saharan dust has a crucial influence on the earth climate system and its emission, transport and deposition are intimately related to, e.g., wind speed, precipitation, temperature and vegetation cover. The alteration in the physical and chemical properties of Saharan dust due to environmental changes is often used to reconstruct the climate of the past. However, to better interpret possible climate changes the dust source regions need to be known. By analysing the mineralogical composition of transported or deposited dust, potential dust source areas can be inferred. Summer dust transport off northwest Africa occurs in the Saharan air layer (SAL). In continental dust source areas, dust is also transported in the SAL; however, the predominant dust input occurs from nearby dust sources with the low-level trade winds. Hence, the source regions and related mineralogical tracers differ with season and sampling location. To test this, dust collected in traps onshore and in oceanic sediment traps off Mauritania during 2013 to 2015 was analysed. Meteorological data, particle-size distributions, back-trajectory and mineralogical analyses were compared to derive the dust provenance and dispersal. For the onshore dust samples, the source regions varied according to the seasonal changes in trade-wind direction. Gibbsite and dolomite indicated a Western Saharan and local source during summer, while chlorite, serpentine and rutile indicated a source in Mauritania and Mali during winter. In contrast, for the samples that were collected offshore, dust sources varied according to the seasonal change in the dust transporting air layer. In summer, dust was transported in the SAL from Mauritania, Mali and Libya as indicated by ferroglaucophane and zeolite. In winter, dust was transported with the trades from Western Sahara as indicated by, e.g., fluellite.

  2. 77 FR 12080 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Cotton Dust...

    Science.gov (United States)

    2012-02-28

    ...; Cotton Dust Standard ACTION: Notice. SUMMARY: The Department of Labor (DOL) is submitting the Occupational Safety and Health Administration sponsored information collection request (ICR) titled, ``Cotton... INFORMATION: The purpose of the cotton dust standard and its information collection requirements is to provide...

  3. Collective cell streams in epithelial monolayers depend on cell adhesion

    International Nuclear Information System (INIS)

    Czirók, András; Varga, Katalin; Méhes, Előd; Szabó, András

    2013-01-01

    We report spontaneously emerging, randomly oriented, collective streaming behavior within a monolayer culture of a human keratinocyte cell line, and explore the effect of modulating cell adhesions by perturbing the function of calcium-dependent cell adhesion molecules. We demonstrate that decreasing cell adhesion induces narrower and more anisotropic cell streams, reminiscent of decreasing the Taylor scale of turbulent liquids. To explain our empirical findings, we propose a cell-based model that represents the dual nature of cell–cell adhesions. Spring-like connections provide mechanical stability, while a cellular Potts model formalism represents surface-tension driven attachment. By changing the relevance and persistence of mechanical links between cells, we are able to explain the experimentally observed changes in emergent flow patterns. (paper)

  4. Dust Episodes in Hong Kong (South China) and their Relationship with the Sharav and Mongolian Cyclones and Jet Streams

    Science.gov (United States)

    Lee, Y. C.; Wenig, Mark; Zhang, Zhenxi; Sugimoto, Nobuo; Larko, Dave; Diehl, Thomas

    2012-01-01

    The study presented in this paper analyses two dust episodes in Hong Kong, one occurring in March 2006 and the other on 22 March 2010. The latter is the worst dust episode on Hong Kong record. The focus is on the relationship between the dust episodes and the Sharav/Mongolian cyclones and jet streams. The 16 March 2006 episode is traceable to a continental-scale Saharan dust outbreak of 5-9 March 2006 caused by the cold front of an East Mediterranean Sharav cyclone arriving at north-west Africa on 5 March 2006. The eastward movement of the cyclone along the North African coast is clearly illustrated in the geopotential height contours. Simulations by the chemistry transport model GOCART provide a visible evidence of the transport as well as an estimate of contributions from the Sahara to the aerosol concentration levels in Hong Kong. The transport simulations suggest that the dust is injected to the polar jet north of the Caspian Sea, while it is transported eastward simultaneously by the more southerly subtropical jet. The major source of dust for Hong Kong is usually the Gobi desert. Despite the effect of remote sources, the 16 March 2006 dust episode was still mainly under the influence of the Mongolian cyclone cold fronts. In the recent episode of 22 March 2010, the influence of the Mongolian cyclone predominated as well. It appears that the concurrent influence of the Sharav and Mongolian cyclones on Hong Kong and East Asia is not a common occurrence. Besides transporting dusts from non-East Asian sources to Hong Kong and East Asia, the strong subtropical jet on 21 March 2010 (i.e. 1 day prior to the major dust episode) is believed to have strengthened an easterly monsoon surge to South China causing the transport of voluminous dusts to Taiwan and Hong Kong the following day.

  5. Dust collection capacity of plants growing in coal mining areas

    International Nuclear Information System (INIS)

    Maiti, S.K.

    1993-01-01

    Plant can act as living filter of dust pollution in coal mining areas, where the amount of suspended particulate matter and dust fall rate is very high. Therefore, plant species growing in coal mining areas are classified as evergreen or deciduous with simple and compound leaf basis. The dust arresting capacity of each leaf is measured and expressed in g/m 2 . The study indicated that evergreen plants with simple, pilose surface, like - Alstonia, Ficus cunea, F. benghalensis and Mangifera indica are good dust catcher than evergreen compound leaves of Cassia siamea, Acacia arabica and Leucaena leucocephala. Deciduous with simple leaves, such as Zizyphus mauritiana, F. religiosa, Psidium guyava are also good dust collectors. Suitable plant species also help in quick reclamation of mined out areas; one practical difficulty for establishment of trees as green belts or reclamation purpose, has been incidence of cattle grazing. This study suggested a systematic way of selecting plant species on the basis of their efficiency in dust control and resistance to cattle grazing. (author). 16 refs., 3 tabs

  6. Collecting Comet Samples by ER-2 Aircraft: Cosmic Dust Collection During the Draconid Meteor Shower in October 2012

    Science.gov (United States)

    Bastien, Ron; Burkett, P. J.; Rodriquez, M.; Frank, D.; Gonzalez, C.; Robinson, G.-A.; Zolensky, M.; Brown, P.; Campbell-Brown, M.; Broce, S.; hide

    2014-01-01

    Many tons of dust grains, including samples of asteroids and comets, fall from space into the Earth's atmosphere each day. NASA periodically collects some of these particles from the Earth's stratosphere using sticky collectors mounted on NASA's high-flying aircraft. Sometimes, especially when the Earth experiences a known meteor shower, a special opportunity is presented to associate cosmic dust particles with a known source. NASA JSC's Cosmic Dust Collection Program has made special attempts to collect dust from particular meteor showers and asteroid families when flights can be planned well in advance. However, it has rarely been possible to make collections on very short notice. In 2012, the Draconid meteor shower presented that opportunity. The Draconid meteor shower, originating from Comet 21P/Giacobini-Zinner, has produced both outbursts and storms several times during the last century, but the 2012 event was not predicted to be much of a show. Because of these predictions, the Cosmic Dust team had not targeted a stratospheric collection effort for the Draconids, despite the fact that they have one of the slowest atmospheric entry velocities (23 km/s) of any comet shower, and thus offer significant possibilities of successful dust capture. However, radar measurements obtained by the Canadian Meteor Orbit Radar during the 2012 Draconids shower indicated a meteor storm did occur October 8 with a peak at 16:38 (+/-5 min) UTC for a total duration of approximately 2 hours.

  7. Mechanical intervention for reducing dust concentration in traditional rice mills.

    Science.gov (United States)

    Pranav, Prabhanjan K; Biswas, Mrinmoy

    2016-08-05

    A huge number of workers are employed in traditional rice mills where they are potentially exposed to dust. In this study a dust collection system was developed to capture the airborne dust in the rice mill. The feeding and sieving section of the mill was identified as major dust creating zone. The dust was captured by creating suitable air stream at feeding and sieving sections of the mill and collected in cyclone dust collector. The air stream was created by blower which was selected on the basis to get minimum air speed of 0.5 m/s in the working zones of workers. It was observed that the developed system is successfully collects the significant amount of dust and able to reduce the dust concentration up to 58%. Further, the respirable dust concentration reduced to below 5 mg/m(3) throughout the mill which is within the recommended limit of dust exposure.

  8. Mechanical intervention for reducing dust concentration in traditional rice mills

    OpenAIRE

    PRANAV, Prabhanjan K.; BISWAS, Mrinmoy

    2016-01-01

    A huge number of workers are employed in traditional rice mills where they are potentially exposed to dust. In this study a dust collection system was developed to capture the airborne dust in the rice mill. The feeding and sieving section of the mill was identified as major dust creating zone. The dust was captured by creating suitable air stream at feeding and sieving sections of the mill and collected in cyclone dust collector. The air stream was created by blower which was selected on the...

  9. Seasonal dynamics of house dust mites in dust samples collected from sleeping places in north-western Poland.

    Science.gov (United States)

    Kosik-Bogacka, D I; Kalisinska, E; Henszel, L; Kuzna-Grygiel, W

    2012-02-01

    The most common families of mites found in house dust are Pyroglyphidae, Glycyphagidae and Acaridae; all are a source of many antigens responsible for allergic diseases. The aim of this study was to examine the seasonal dynamics of allergenic mite populations in dust samples collected from sleeping places in apartments in north-western Poland. The mites were isolated from the dust using a saturated saline floating method. In 132 dust samples we determined: Dermatophagoides farinae, Dermatophagoides pteronyssinus, Euroglyphus maynei, Hirstia sp., Chortoglyphus arcuatus, Lepidoglyphus destructor, Gohieria fusca and Cheyletus sp. The greatest frequency was observed for D. farinae, D. pteronyssinus, Ch. arcuatus and Cheyletus sp., in the fourth quarter and D. farinae in the third quarter. Smaller coefficients of dominance were found for D. pteronyssinus, Ch. arcuatus and Cheyletus sp., and their greatest mean concentrations were found in the first and fourth quarters. Given the division of the year into heating and non-heating seasons, mites D. farinae and D. pteronyssinus achieved the highest mean concentration in the first season, and Cheyletus sp. in the second season. The analysis of the participation of developmental stages showed that the adults of D. farinae were more prevalent than juveniles in the first, second and third quarters, and imago stages of D. pteronyssinus were more numerous in relation to juveniles in the first, third and fourth quarters. The results confirm the high incidence of house dust mites in sleeping places in north-western Poland dwellings; the best conditions for the development of these mites, mainly D. farinae and D. pteronyssinus, occur in the fourth quarter and are the least favourable in the second quarter. In many cases, these results are consistent with data from other parts of Poland collected by various authors. © 2011 Blackwell Verlag GmbH.

  10. Mineralogical analysis of dust collected from typical recycling line of waste printed circuit boards.

    Science.gov (United States)

    Wang, Fangfang; Zhao, Yuemin; Zhang, Tao; Duan, Chenlong; Wang, Lizhang

    2015-09-01

    As dust is one of the byproducts originating in the mechanical recycling process of waste printed circuit boards such as crushing and separating, from the viewpoints of resource reuse and environmental protection, an effective recycling method to recover valuable materials from this kind of dust is in urgent need. In this paper, detailed mineralogical analysis on the dust collected from a typical recycling line of waste printed circuit boards is investigated by coupling several analytical techniques. The results demonstrate that there are 73.1wt.% organic matters, 4.65wt.% Al, 4.55wt.% Fe, 2.67wt.% Cu and 1.06wt.% Pb in the dust, which reveals the dust is worthy of reuse and harmful to environment. The concentration ratios of Fe, Mn and Zn can reach 12.35, 12.33 and 6.67 respectively by magnetic separation. The yield of dust in each size fraction is nonuniform, while the yield of -0.75mm size fraction is up to 51.15wt.%; as the particle size decreases, the content of liberated metals and magnetic materials increase, and metals are mainly in elemental forms. The F, Cl and Br elements combing to C in the dust would make thermal treatment dangerous to the environment. Based on these results, a flowsheet to recycle the dust is proposed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Granulometry, microbial composition and biological activity of dusts collected in French dairy farms.

    Science.gov (United States)

    Pfister, Hugo; Morzadec, Claudie; Le Cann, Pierre; Madec, Laurent; Lecureur, Valérie; Chouvet, Martine; Jouneau, Stéphane; Vernhet, Laurent

    2017-10-01

    Dairy working increases the prevalence of lower airway respiratory diseases, especially COPD and asthma. Epidemiological studies have reported that chronic inhalation of organic dusts released during specific daily tasks could represent a major risk factor for development of these pathologies in dairy workers. Knowledge on size, nature and biological activity of such organic dusts remain however limited. To compare size distribution, microbial composition and cellular effects of dusts liberated by the spreading of straw bedding in five French dairy farms located in Brittany. Mechanized distribution of straw bedding generated a cloud of inhalable dusts in the five dairy farms' barns. Thoracic particles having a 3-7.5µm size constituted 58.9-68.3% of these dusts. Analyses of thoracic dusts by next generation sequencing showed that the microbial dust composition differed between the five French farms, although Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria represent more than 97.5% of the bacterial phyla detected in each sample. Several bacteria genera comprising of human pathogenic species, such as Pseudomonas, Staphylococcus, Thermoactinomyces or Saccharopolyspora were identified. Cladosporium and Alternaria fungal genera, which are potent environmental determinants of respiratory symptoms, were detected in dusts collected in the five farms and their levels reached 15.5-51.1% and 9-24.7% of assignable fungal sequences in each sample, respectively. Finally, all dust samples significantly and strongly increased the expression of the pro-inflammatory TNF-α, IL-1β, IL-6 and IL-8 cytokines at both mRNA and protein levels in human monocyte-derived macrophages. Their effects were dose-dependent and detectable from 1µg/ml. The intensity of the macrophage responses however differed according to the samples. Our results strengthen the hypothesis that organic dusts released during the distribution of straw bedding are mainly constituted of thoracic particles

  12. Dust particles from comets and asteroids collected at the Earth's orbit: Parent-daughter relationships

    Science.gov (United States)

    Jackson, A. A.; Zook, H. A.

    1991-01-01

    The relative contributions of comets and asteroids to the reservoir of dust in the interplanetary medium is not well known. There are direct observations of dust released from comets and there is evidence to associate the IRAS dust bands with possible collisions of Asteroids in the main belt. It is believed that one may combine lab analysis of the physics and chemistry of captured particles with orbital data in order to identify comet and asteroid parent bodies. It is possible to use the collected orbits of the dust to connect with its source in two ways. One is to consider the long time orbit evolution of the dust under Poynting-Robertson drag. The other is to look at the prompt orbit change of dust from comets onto trajectories that intersect the earth's orbit. In order to characterize the orbits of dust particles evolved over a long period of time, a study of its orbital evolution was undertaken. Various parameters associated with these dust orbits as they cross the Earth's orbit were considered in order to see if one may discriminate between particles evolved from comets and asteroids. The method was to calculate by a numerical procedure the orbits of dust particles after they left their parent bodies. It appears that as the particles pass the Earth's orbit, asteroidal grains and cometary grains can be differentiated on the basis of their measured orbital eccentricities even after much planetary perturbation. Broad parent daughter associations can be made on this basis from measurement of their trajectories intercepted in earth orbit.

  13. Exhaust, Dust Collection and Ventilation Systems. Module SH-44. Safety and Health.

    Science.gov (United States)

    Center for Occupational Research and Development, Inc., Waco, TX.

    This student module on exhaust, dust collection, and ventilation systems is one of 50 modules concerned with job safety and health. This module discusses the types of contaminants that can be controlled by ventilation, the types of ventilation systems, and the component parts of local exhaust systems. Following the introduction, 10 objectives…

  14. 77 FR 38323 - Proposed Extension of Existing Information Collection; Respirable Coal Mine Dust Sampling

    Science.gov (United States)

    2012-06-27

    ..., silicosis, and chronic bronchitis, known collectively as ``black lung.'' These diseases are debilitating and... dust levels since 1970 and, consequently, the prevalence rate of black lung among coal miners, severe... Safety and Health (NIOSH) indicate that black lung remains an occupational health risk among our nation's...

  15. Soil sample collection and analysis for the Fugitive Dust Characterization Study

    Science.gov (United States)

    Ashbaugh, Lowell L.; Carvacho, Omar F.; Brown, Michael S.; Chow, Judith C.; Watson, John G.; Magliano, Karen C.

    A unique set of soil samples was collected as part of the Fugitive Dust Characterization Study. The study was carried out to establish whether or not source profiles could be constructed using novel analytical methods that could distinguish soil dust sources from each other. The soil sources sampled included fields planted in cotton, almond, tomato, grape, and safflower, dairy and feedlot facilities, paved and unpaved roads (both urban and rural), an agricultural staging area, disturbed land with salt buildup, and construction areas where the topsoil had been removed. The samples were collected using a systematic procedure designed to reduce sampling bias, and were stored frozen to preserve possible organic signatures. For this paper the samples were characterized by particle size (percent sand, silt, and clay), dry silt content (used in EPA-recommended fugitive dust emission factors), carbon and nitrogen content, and potential to emit both PM 10 and PM 2.5. These are not the "novel analytical methods" referred to above; rather, it was the basic characterization of the samples to use in comparing analytical methods by other scientists contracted to the California Air Resources Board. The purpose of this paper is to document the methods used to collect the samples, the collection locations, the analysis of soil type and potential to emit PM 10, and the sample variability, both within field and between fields of the same crop type.

  16. Output channel design for collecting closely-spaced particle streams from spiral inertial separation devices

    Directory of Open Access Journals (Sweden)

    Caffiyar Mohamed Yousuff

    2017-08-01

    Full Text Available Recent advances in inertial microfluidics designs have enabled high throughput, label-free separation of cells for a variety of bioanalytical applications. Various device configurations have been proposed for binary separation with a focus on enhancing the separation distance between particle streams to improve the efficiency of separate particle collection. These configurations have not demonstrated scaling beyond 3 particle streams either because the channel width is a constraint at the collection outlets or particle streams would be too closely spaced to be collected separately. We propose a method to design collection outlets for inertial focusing and separation devices which can collect closely-spaced particle streams and easily scale to an arbitrary number of collection channels without constraining the outlet channel width, which is the usual cause of clogging or cell damage. According to our approach, collection outlets are a series of side-branching channels perpendicular to the main channel of egress. The width and length of the outlets can be chosen subject to constraints from the position of the particle streams and fluidic resistance ratio computed from fluid dynamics simulations. We show the efficacy of this approach by demonstrating a successful collection of upto 3 particle streams of 7μm, 10μm and 15μm fluorescent beads which have been focused and separated by a spiral inertial device with a separation distance of only 10μm -15μm. With a throughput of 1.8mL/min, we achieved collection efficiency exceeding 90% for each particle at the respective collection outlet. The flexibility to use wide collection channels also enabled us to fabricate the microfluidic device with an epoxy mold that was created using xurography, a low cost, and imprecise fabrication technique.

  17. Efficiency of Different Sampling Tools for Aquatic Macroinvertebrate Collections in Malaysian Streams

    Science.gov (United States)

    Ghani, Wan Mohd Hafezul Wan Abdul; Rawi, Che Salmah Md; Hamid, Suhaila Abd; Al-Shami, Salman Abdo

    2016-01-01

    This study analyses the sampling performance of three benthic sampling tools commonly used to collect freshwater macroinvertebrates. Efficiency of qualitative D-frame and square aquatic nets were compared to a quantitative Surber sampler in tropical Malaysian streams. The abundance and diversity of macroinvertebrates collected using each tool evaluated along with their relative variations (RVs). Each tool was used to sample macroinvertebrates from three streams draining different areas: a vegetable farm, a tea plantation and a forest reserve. High macroinvertebrate diversities were recorded using the square net and Surber sampler at the forested stream site; however, very low species abundance was recorded by the Surber sampler. Relatively large variations in the Surber sampler collections (RVs of 36% and 28%) were observed for the vegetable farm and tea plantation streams, respectively. Of the three sampling methods, the square net was the most efficient, collecting a greater diversity of macroinvertebrate taxa and a greater number of specimens (i.e., abundance) overall, particularly from the vegetable farm and the tea plantation streams (RVwater quality, but each sample required a slightly longer processing time (±20 min) compared with those gathered via the other samplers. In conclusion, all three apparatuses were suitable for macroinvertebrate collection in Malaysian streams and gathered assemblages that resulted in the determination of similar biological water quality classes using the Family Biotic Index (FBI) and the Biological Monitoring Working Party (BMWP). However, despite a slightly longer processing time, the square net was more efficient (lowest RV) at collecting samples and more suitable for the collection of macroinvertebrates from deep, fast flowing, wadeable streams with coarse substrates. PMID:27019685

  18. Lab Streaming Layer Enabled Myo Data Collection Software User Manual

    Science.gov (United States)

    2017-06-07

    release; distribution unlimited. 13. SUPPLEMENTARY NOTES 14. ABSTRACT The US Army Research Laboratory conducts research in multimodal human ...gesture classification using data acquired from various physiological sensors. The Myo armband is one such sensor used for the data collection. A simple...operating system platforms. These data can be used to train classifiers to predict human hand gestures.* Further details and specifications are

  19. Decontamination by foams: A promising treatment for the removal of radioactive dust from gas streams

    International Nuclear Information System (INIS)

    Mitchell, J.P.

    1989-06-01

    Foams provide a promising method for the treatment of gas streams containing radioactive aerosol particles. A review of the literature has been undertaken to define and assess the mechanics of aerosol behaviour in contact with foams. Applications are also examined in which foams have been used to treat aerosols. Key issues are identified which require further study. In particular, the efficiency of sub-micron particle removal can be determined using recently developed analysers and the use of the process gas to generate the foam could have a major impact on the design of commercial units. (author)

  20. Microphysical properties of Sahara dust collected during the Fennec campaign in 2011

    Science.gov (United States)

    Rocha Lima, Adriana; Vanderlei Martins, Jose; Todd, Martin; Washington, Richard; Marshan, John; Allen, Christopher; Engelstaedter, Sebastian; Cavazos-Guerra, Carolina

    2013-04-01

    Ground measurements of the atmospheric particles are extremely important in order to integrate aerial and remote sensing measurements. In situ aerosol filters collection and in situ measurements of aerosol properties were performed at two locations: Bordj Badj Mokthar in Algeria (Supersite 1) and Bir Moghrein in Mauritania (Supersite 2) in June 2011, as part of the Fennec project over the central Sahara. At Supersite 1 an automatized system consisting of an Aerosol Sampling Station (LASS1) and an integrated Reflectometer-Nephelometer allowed simultaneous collection of aerosol particles on Nuclepore filters (coarse and fine mode) and continuous measurement of the scattering and absorption properties of the aerosol particles. At the Supersite 2 in Mauritania a second Aerosol Sampling Station (LASS2) was also operational during the Fennec campaign collecting filters continually. Filters were sent back to laboratory for a series of analysis to obtain the optical and microphysical properties of the sampled aerosol particles. Gravimetric analysis of each individual filter gives the concentration of aerosol particles in μg-m3. Particle size distribution is obtained by scanning electron microscopy and the spectral reflectance of the filters from (350-2200nm) is being measured to derive the spectral mass absorption coefficient and refractive index of the aerosol particles. Preliminary analyses of Supersite 1 for 463nm, 525nm and 637nm wavelength show single scattering albedo 0.94, 0.96 and 0.98 respectively. X-Ray Fluorescence analyses of some of the filters from this location indicate Si, Fe, Al and Ca as the main constituent elements of these particles. At Supersite 2, it was observed periods of very clean conditions with concentrations below 10 μg-m3 (June 6-7, Maritime Phase) and periods of high dust concentration, with peaks of 70 μg-m3 (June 20-21, Heat Low Phase). Scanning electron microscopy analysis show high shape heterogeneity of particles and also the

  1. Particle size distribution of dust collected from Alcator C-MOD

    International Nuclear Information System (INIS)

    Gorman, S.V.; Carmack, W.J.; Hembree, P.B.

    1998-01-01

    There are important safety issues associated with tokamak dust, accumulated primarily from sputtering and disruptions. The dust may contain tritium, it may be activated, chemically toxic, and chemically reactive. The purpose of this paper is to present results from analyses of particulate collected from the Alcator C-MOD tokamak located at Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts. The sample obtained from C-MOD was not originally intended for examination outside of MIT. The sample was collected with the intent of performing only a composition analysis. However, MIT provided the INEEL with this sample for particle analysis. The sample was collected by vacuuming a section of the machine (covering approximately 1/3 of the machine surface) with a coarse fiber filter as the collection surface. The sample was then analyzed using an optical microscope, SEM microscope, Microtrac FRA particle size analyzer. The data fit a log-normal distribution. The count median diameter (CMD) of the samples ranged from 0.3 microm to 1.1 microm with geometric standard deviations (GSD) ranging from 2.8 to 5.2 and a mass median diameter (MMD) ranging from 7.22 to 176 microm

  2. Decontamination by foams: a promising treatment for the removal of radioactive dust from gas streams

    International Nuclear Information System (INIS)

    Mitchell, J.P.

    1989-06-01

    Foams provide a promising method for the treatment of gas streams containing radioactive aerosol particles. They contain a very large surface area of liquid-gas interface in small cells; thus it is possible to achieve rapid capture of airborne particles in the liquid phase, particularly if the aerosol can be incorporated in the foam structure. The foam can be collapsed into a small volume of liquid, immobilising any trapped aerosol in a form that may be treated as liquid waste. A review of the literature has been undertaken to define and assess the mechanics of aerosol behaviour in contact with foams. Applications are also examined in which foams have been used to treat aerosols. Key issues are identified which require further study. In particular, the efficiency of sub-micron particle removal can be determined using recently developed analysers and the use of the process gas to generate the foam could have a major impact on the design of commercial units. (author)

  3. Urban and Rural MSW Stream Characterization for Separate Collection Improvement

    Directory of Open Access Journals (Sweden)

    Simona Ciuta

    2015-01-01

    Full Text Available In the new legislation framework enacted by new member countries of the European Union (EU, the characterization of municipal solid waste (MSW represents an important instrument for local governments and sanitation operators in setting and achieving targets for waste recycling and recovery. This paper presents the results of a study conducted in accordance with the Romanian methodology for domestic wastes characterization ROMECOM, aiming to provide a proper basis for developing clear and realistic forecasts in current municipal waste management, based on MSW composition and generation rate. The analyzed MSW came both from areas where the waste is collected in mixed and separate ways, in urban and rural areas. The MSW composition by fraction is detailed for dense urban areas, urban areas, rural and touristic areas from Romania. Based on these results, the MSW composition was determined for the eight development regions in Romania, and a generation rate of 0.9·kgMSW inhabitant−1·day−1 for the urban region and 0.4·kgMSW inh−1·day−1 for the rural region was established. The calorific values of urban and rural areas were determined as 6801 kJ·kg−1 and 5613 kJ·kg−1, respectively. In the perspective of sustainable development in this technical area, based on the obtained results and on the prognosis made for the following years, two proposals for urban and rural areas were developed for MSW treating options improvement. The two systems are characterized by selective collection (different efficiencies for urban and rural areas with subsequent recovery of the separated materials and energy recovery of the residual waste in a large-scale waste to energy (WTE plant.

  4. Differences in particle size distributions collected by two wood dust samplers: preliminary findings

    International Nuclear Information System (INIS)

    Campopiano, A.; Olori, A.; Basili, F.; Ramires, D.; Zakrzewska, A.M.

    2008-01-01

    The International Agency for Research on Cancer (IARC) classification of wood dust as carcinogenic to humans, and the threshold limit value (TLV) of 5 mg/m 3 weighted over an 8-hour work day as defined by Italian legislation, have raised the issue of dust risk assessments in all woodworking environments. The aim is to characterize the particle size distribution for wood particles collected by two samplers used for collecting the inhalable fraction: the IOM sampler (Institute of Occupational Medicine, Edinburgh, Scotland) and the conical sampler also known in Italy as conetto. These two sampling heads were chosen mainly because the Italian conical sampler, used in the past for total dust sampling, is the most widely used by the Italian Prevention Services and analysis laboratories in general, whereas the IOM sampler was specifically designed to collect the inhalable fraction of airborne particles. The devices were placed side by side within the worker's breathing zone. In addition, another IOM sampler not connected to the personal sampling pump was placed on the same worker, thus functioning as a passive sampler capable of collecting projectile particles normally produced during processing. A Scanning Electron Microscope (SEM) coupled with energy dispersive X-ray spectrometry (EDAX) was used to count the number of particles collected on the sampling filters. The size of each particle identified by the SEM was determined by measuring its mean diameter. The SEM analysis revealed that the average size of the largest particles collected by the conetto sampler did not exceed 150 μm, whereas the size of particles collected by the IOM sampler was up to 350 μm. Indeed, the analysis of the filters of the passive IOM samplers showed that particles with mean diameters larger than 100 μm were collected, although the calculated percentage was very low (on average, approximately 1%). This does not mean that their gravimetric contribution is negligible; indeed, the weight of

  5. 1500-year Record of trans-Pacific Dust Flux collected from the Denali Ice Core, Mt. Hunter, Alaska

    Science.gov (United States)

    Saylor, P. L.; Osterberg, E. C.; Koffman, B. G.; Winski, D.; Ferris, D. G.; Kreutz, K. J.; Wake, C. P.; Handley, M.; Campbell, S. W.

    2016-12-01

    Mineral dust aerosols are a critical component of the climate system through their influence on atmospheric radiative forcing, ocean productivity, and surface albedo. Dust aerosols derived from Asian deserts are known to reach as far as Europe through efficient transport in the upper tropospheric westerlies. While centennially-to-millennially resolved Asian dust records exist over the late Holocene from North Pacific marine sediment cores and Asian loess deposits, a high-resolution (sub-annual to decadal) record of trans-Pacific dust flux will significantly improve our understanding of North Pacific dust-climate interactions and provide paleoclimatological context for 20th century dust activity. Here we present an annually resolved 1500-year record of trans-Pacific dust transport based on chemical and physical dust measurements in parallel Alaskan ice cores (208 m to bedrock) collected from the summit plateau of Mt. Hunter in Denali National Park. The cores were sampled at high resolution using a continuous melter system with discrete analyses for major ions (Dionex ion chromatograph), trace elements (Element2 inductively coupled plasma mass spectrometer), and stable water isotope ratios (Picarro laser ringdown spectroscopy), and continuous flow analysis for dust concentration and size distribution (Klotz Abakus). We compare the ice core dust record to instrumental aerosol stations, satellite observations, and dust model data from the instrumental period, and evaluate climatic controls on dust emission and trans-Pacific transport using climate reanalysis data, to inform dust-climate relationships over the past 1500 years. Physical particulate and chemical data demonstrate remarkable fidelity at sub-annual resolution, with both displaying a strong springtime peak consistent with periods of high dust activity over Asian desert source regions. Preliminary results suggest volumetric mode typically ranges from 4.5 - 6.5 um, with a mean value of 5.5 um. Preliminary

  6. Guidelines for the collection of continuous stream water-temperature data in Alaska

    Science.gov (United States)

    Toohey, Ryan C.; Neal, Edward G.; Solin, Gary L.

    2014-01-01

    Objectives of stream monitoring programs differ considerably among many of the academic, Federal, state, tribal, and non-profit organizations in the state of Alaska. Broad inclusion of stream-temperature monitoring can provide an opportunity for collaboration in the development of a statewide stream-temperature database. Statewide and regional coordination could reduce overall monitoring cost, while providing better analyses at multiple spatial and temporal scales to improve resource decision-making. Increased adoption of standardized protocols and data-quality standards may allow for validation of historical modeling efforts with better projection calibration. For records of stream water temperature to be generally consistent, unbiased, and reproducible, data must be collected and analyzed according to documented protocols. Collection of water-temperature data requires definition of data-quality objectives, good site selection, proper selection of instrumentation, proper installation of sensors, periodic site visits to maintain sensors and download data, pre- and post-deployment verification against an NIST-certified thermometer, potential data corrections, and proper documentation, review, and approval. A study created to develop a quality-assurance project plan, data-quality objectives, and a database management plan that includes procedures for data archiving and dissemination could provide a means to standardize a statewide stream-temperature database in Alaska. Protocols can be modified depending on desired accuracy or specific needs of data collected. This document is intended to guide users in collecting time series water-temperature data in Alaskan streams and draws extensively on the broader protocols already published by the U.S. Geological Survey.

  7. Introducing a new stratospheric dust-collecting system with potential use for upper atmospheric microbiology investigations.

    Science.gov (United States)

    Della Corte, Vincenzo; Rietmeijer, Frans J M; Rotundi, Alessandra; Ferrari, Marco

    2014-08-01

    The stratosphere is a known host to terrestrial microbes of most major biological lineages, but it is also host to incoming meteoric dust. Our goal is to (1) introduce DUSTER (Dust in the Upper Stratosphere Tracking Experiment and Retrieval), an active collector for the nondestructive collection of nano- to micrometer particles in the stratosphere between 30 and 40 km altitude, and (2) demonstrate that even a single particle can be collected free of resident atmospheric and laboratory contaminant particles. DUSTER improves the pervasive and persistent contamination problem in the field of aerobiology research. Here, we demonstrate the collector's advances by the identification of a (terrestrial) spore particle found among a population of nanometer-scale inorganic meteoric particles. This was possible because the size, shape, morphology, and chemical composition of each particle can be determined while still on the collector surface. Particles can be removed from DUSTER for specific laboratory analyses. So far, DUSTER has not been fitted for aerobiological purposes; that is, no attempts were made to sterilize the collector other than with isopropyl alcohol. Its design and laboratory protocols, however, allow adjustments to dedicated aerobiological sampling opportunities.

  8. The value of long-term stream invertebrate data collected by citizen scientists

    Science.gov (United States)

    Patrick M. Edwards; Stefano. Goffredo

    2016-01-01

    The purpose of this investigation was to systematically examine the variability associated with temporally-oriented invertebrate data collected by citizen scientists and consider the value of such data for use in stream management. Variability in invertebrate data was estimated for three sources of variation: sampling, within-reach spatial and long-term temporal. Long-...

  9. STREAM

    DEFF Research Database (Denmark)

    Godsk, Mikkel

    This paper presents a flexible model, ‘STREAM’, for transforming higher science education into blended and online learning. The model is inspired by ideas of active and collaborative learning and builds on feedback strategies well-known from Just-in-Time Teaching, Flipped Classroom, and Peer...... Instruction. The aim of the model is to provide both a concrete and comprehensible design toolkit for adopting and implementing educational technologies in higher science teaching practice and at the same time comply with diverse ambitions. As opposed to the above-mentioned feedback strategies, the STREAM...

  10. A detailed characterization of the Saharan dust collected during the Fennec campaign in 2011: in situ ground-based and laboratory measurements

    OpenAIRE

    Rocha-Lima, Adriana; Vanderlei Martins, J; Remer, Lorraine A; Todd, Martin; Marsham, John H; Engelstaedter, Sebastian; Ryder, Claire L; Cavazos-Guerra, Carolina; Artaxo, Paulo; Colarco, Peter; Washington, Richard

    2018-01-01

    Millions of tons of mineral dust are lifted by the wind from arid surfaces and transported around the globe every year. The physical and chemical properties of the mineral dust are needed to better constrain remote sensing observations and are of fundamental importance for the understanding of dust atmospheric processes. Ground-based in situ measurements and in situ filter collection of Saharan dust were obtained during the Fennec campaign in the central Sahara in 2011. This paper presents re...

  11. Extracting lunar dust parameters from image charge signals produced by the Lunar Dust Experiment

    Science.gov (United States)

    Stanley, J.; Kempf, S.; Horanyi, M.; Szalay, J.

    2015-12-01

    The Lunar Dust Experiment (LDEX) onboard the Lunar Atmosphere and Dust Environment Explorer (LADEE) is an impact ionization dust detector used to characterize the lunar dust exosphere generated by the impacts of large interplanetary particles and meteor streams (Horanyi et al., 2015). In addition to the mass and speed of these lofted particles, LDEX is sensitive to their charge. The resulting signatures of impact events therefore provide valuable information about not only the ambient plasma environment, but also the speed vectors of these dust grains. Here, impact events produced from LDEX's calibration at the Dust Accelerator Laboratory are analyzed using an image charge model derived from the electrostatic simulation program, Coulomb. We show that parameters such as dust grain speed, size, charge, and position of entry into LDEX can be recovered and applied to data collected during LADEE's seven-month mission.

  12. 78 FR 28242 - Proposed Information Collection; Cleanup Program for Accumulations of Coal and Float Coal Dusts...

    Science.gov (United States)

    2013-05-14

    ... Act of 1995 (PRA). This program helps to assure that requested data can be provided in the desired... rock dust application is necessary to protect miners from the potential of a float coal dust explosion... other combustibles. Based on its investigation of the April 5, 2010 explosion at the Upper Big Branch...

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

    Energy Technology Data Exchange (ETDEWEB)

    Bryan, Charles R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Enos, David George [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-07-01

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

  14. Impurities of Resorcinol Bis(diphenyl phosphate) in Plastics and Dust Collected on Electric/Electronic Material.

    Science.gov (United States)

    Ballesteros-Gómez, Ana; Aragón, Álvaro; Van den Eede, Nele; de Boer, Jacob; Covaci, Adrian

    2016-02-16

    Resorcinol bis(diphenylphosphate) (RDP) is an organophosphorus flame retardant widely used in electric and electronic equipment. It has been detected in house dust of several European countries according to recent literature. Similar to other flame retardants, RDP formulations and products treated with RDP, such as plastics, can contain RDP impurities, byproducts and breakdown products. In this study, we use screening methods based on wide scope solvent extraction and high resolution time-of-flight mass spectrometry for the identification of RDP related compounds in products and in dust. We analyzed both plastics from electrical/electronic equipment that contained RDP and indoor dust collected on and around surfaces of this equipment. A variety of compounds, namely TPHP, hydroxylated TPHP and RDP (meta-HO-TPHP and meta-HO-RDP), dihydroxylated TPHP, RDP with the loss of a phenyl group (RDP-[Phe]) and RDP oligomers were detected in plastics containing high levels of RDP. Regarding dust samples collected on electronics, TPHP meta-HO-TPHP, meta-HO-RDP, RDP-[Phe] and RDP oligomers were detected. High concentrations of meta-HO-TPHP (20-14 227 ng/g), TPHP (222-50 728 ng/g) and RDP (23-29 118 ng/g) were found in many of the dust samples, so that these compounds seem to easily migrate into the environment. These RDP impurities, byproducts and breakdown products are for the first time reported in indoor dust. Meta-HO-TPHP could be relevant for future biomonitoring studies concerning flame retardants.

  15. General principles for the formation of dust self-organizing structures. Dust collective attraction and plasma crystal formation

    International Nuclear Information System (INIS)

    Tsytovich, V.N.

    2005-01-01

    It is demonstrated that a homogeneous dusty plasma is universally unstable to form structures. The effect of collective grain attraction is a basic phenomenon for the proposed new paradigm (general principles) for the plasma crystal formation

  16. Stream temperature data collection standards for Alaska: Minimum standards to generate data useful for regional-scale analyses

    Directory of Open Access Journals (Sweden)

    Sue Mauger

    2015-09-01

    New hydrological insights for the region: We defined 10 minimum data collection standards for continuous stream temperature data in Alaska. The standards cover data logger accuracy and range, data collection sampling frequency and duration, site selection, logger accuracy checks, data evaluation, file formats, metadata, and data sharing. We hope that the adoption of minimum standards will encourage rapid, but structured, growth in comparable stream temperature monitoring efforts in Alaska that will be used to understand current and future trends in thermal regimes.

  17. Metal distribution in road dust samples collected in an urban area close to a petrochemical plant at Gela, Sicily

    Science.gov (United States)

    Manno, Emanuela; Varrica, Daniela; Dongarrà, Gaetano

    Eight samples of road dust were collected from three different localities (industrial, urban, peripheral) of the town of Gela (Italy) to characterize their chemical composition and to assess (a) the influence of the petrochemical plant and the urban traffic on the trace element content in different grain-size fractions of street dust and (b) the solid-phase speciation of the analysed metal using sequential extraction. The samples were sieved into six particle size ranges: 500-250, 250-125, 125-63, 63-40, 40-20 and <20 μm and then analysed for 15 trace elements by ICP-MS. Sequential extraction of metals was performed on each subsample. A principal component analysis was also carried out to define the possible origin of metals in dusts. A comparison was made between the trace metal concentrations in road dust and those in main local outcropping rocks. The obtained results, indicate, that the road dust samples contain non-soil-derived elements, whose primary contributors appear to be vehicular traffic and the nearby petrochemical plant. Traffic appears to be responsible for the high levels of Ba, Cu, Cr, Mo, Pb, Sb and Zn. High concentrations of Ni, V and, partly, Ba and Cr were associated with emissions from the petrochemical plant. With respect to the local background, Sb was the most highly enriched trace element in the road dusts. Results of sequential extraction analysis show that most metals are mainly distributed in the non-residual fractions and particularly in the organic/sulphide and Fe-Mn oxides fractions. They also point to superficial adsorption as an important transfer mechanism of trace metals from their sources to the environment.

  18. Featured collection introduction: Connectivity of streams and wetlands to downstream waters

    Science.gov (United States)

    Alexander, Laurie C.; Fritz, Ken M.; Schofield, Kate; Autrey, Bradley; DeMeester, Julie; Golden, Heather E.; Goodrich, David C.; Kepner, William G.; Kiperwas, Hadas R.; Lane, Charles R.; LeDuc, Stephen D.; Leibowitz, Scott; McManus, Michael G.; Pollard, Amina I.; Ridley, Caroline E.; Vanderhoof, Melanie; Wigington, Parker J.

    2018-01-01

    Connectivity is a fundamental but highly dynamic property of watersheds. Variability in the types and degrees of aquatic ecosystem connectivity presents challenges for researchers and managers seeking to accurately quantify its effects on critical hydrologic, biogeochemical, and biological processes. However, protecting natural gradients of connectivity is key to protecting the range of ecosystem services that aquatic ecosystems provide. In this featured collection, we review the available evidence on connections and functions by which streams and wetlands affect the integrity of downstream waters such as large rivers, lakes, reservoirs, and estuaries. The reviews in this collection focus on the types of waters whose protections under the U.S. Clean Water Act have been called into question by U.S. Supreme Court cases. We synthesize 40+ years of research on longitudinal, lateral, and vertical fluxes of energy, material, and biota between aquatic ecosystems included within the Act's frame of reference. Many questions about the roles of streams and wetlands in sustaining downstream water integrity can be answered from currently available literature, and emerging research is rapidly closing data gaps with exciting new insights into aquatic connectivity and function at local, watershed, and regional scales. Synthesis of foundational and emerging research is needed to support science‐based efforts to provide safe, reliable sources of fresh water for present and future generations.

  19. Phthalate and PAH concentrations in dust collected from Danish homes and daycare centers

    DEFF Research Database (Denmark)

    Langer, Sarka; Weschler, Charles J.; Fischer, Andreas

    2010-01-01

    .28-0.45). The dust levels of several phthalates (BBzP, DnBP and DEHP) were substantially lower than those measured in a comparable study conducted 6-7 years earlier in Sweden. Although usage patterns in Denmark differ from those in Sweden, the current results may also reflect a change in the plasticizers...

  20. Sample collection: an overview of the Hydrogeochemical and Stream Sediment Reconnaissance Program

    International Nuclear Information System (INIS)

    Bolivar, S.L.

    1979-01-01

    A Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) for uranium is currently being conducted throughout the conterminous United States and Alaska. The HSSR is part of the National Uranium Resource Evaluation sponsored by the US Department of Energy. This ambitious geochemical reconnaissance program is conducted by four national laboratories: Los Alamos Scientific Laboratory, Lawrence Livermore Laboratory, Oak Ridge Gaseous Diffusion Plant, and Savannah River Laboratory. The program is based on an extensive review of world literature, reconnaissance work done in other countries, and pilot studies conducted by each laboratory. Sample-collection methods and sample density are determined to optimize the probability of detecting potential uranium mineralization. To achieve this aim, each laboratory has developed independent standardized field collection procedures that are designed for its section of the country. Field parameters such as pH, conductivity, climate, geography, and geology are recorded at each site. Most samples are collected at densities of one sample site per 10 to 23 km 2 . The HSSR program has helped to improve existing hydrogeochemical reconnaissance exploration techniques. In addition to providing industry with data that may help to identify potential uranium districts and to extend known uranium provinces, the HSSR also provides multi-element analytical data, which can be used in water quality, soil, sediment, environmental, and base-metal exploration studies

  1. Health effects following subacute exposure to geogenic dust collected from active drainage surfaces (Nellis Dunes Recreation Area, Las Vegas, NV

    Directory of Open Access Journals (Sweden)

    Jamie C. DeWitt

    Full Text Available The specific health effects of direct inhalation of fine minerogenic dusts generated by natural soil surfaces remain poorly known and relatively little researched. To learn more about this exposure and its contribution to human health effects, we surveyed surface sediment and characterized dust from the Nellis Dunes Recreation Area (NDRA in Clark County, Nevada, a popular off-road vehicle (ORV recreational site. Dry drainage systems at NDRA are commonly used as natural trail systems for ORV recreation; these surfaces also are characterized by high concentrations of heavy metals. Geogenic dust with a median diameter of 4.05 μm, collected from drainage surfaces at NDRA contained a total elemental concentration of aluminum (79,651 μg/g, vanadium (100 μg/g, chromium (54 μg/g, manganese (753 μg/g, iron (33,266 μg/g, cobalt (14 μg/g, copper (37 μg/g zinc (135 μg/g, arsenic (71 μg/g, strontium (666 μg/g, cesium (15 μg/g, lead (34 μg/g, and uranium (54.9 μg/g. Adult female B6C3F1 mice exposed via oropharyngeal aspiration to 0.01–100 mg dust/kg body weight, four times, a week apart, for 28-days, were evaluated for immuno- and neurotoxicological outcomes 24 h after the last exposure. Antigen-specific IgM responses were dose-responsively suppressed at 0.1, 1.0, 10 and 100 mg/kg. Splenic lymphocytic subpopulations, hematological and clinical chemistry parameters were affected. In brain tissue, antibodies against NF-68, and GFAP were not affected, whereas IgM antibodies against MBP were reduced by 26.6% only in the highest dose group. A lowest observed adverse effect level (LOAEL of 0.1 mg/kg/day and a no observed adverse effect level (NOAEL of 0.01 mg/kg/day were derived based on the antigen primary IgM responses after subacute exposure to this geogenic dust. Keywords: Geogenic dust, Heavy metals, Minerals, Lung exposure, Immunotoxicity, Neurotoxicity

  2. Collection and analysis of samples for polycyclic aromatic hydrocarbons in dust and other solids related to sealed and unsealed pavement from 10 cities across the United States, 2005-07

    Science.gov (United States)

    Van Metre, Peter C.; Mahler, Barbara J.; Wilson, Jennifer T.; Burbank, Teresa L.

    2008-01-01

    Parking lots and driveways are dominant features of the modern urban landscape, and in the United States, sealcoat is widely used on these surfaces. One of the most widely used types of sealcoat contains refined coal tar; coal-tar-based sealcoat products have a mean polycyclic aromatic hydrocarbon (PAH) concentration of about 5 percent. A previous study reported that parking lots in Austin, Texas, treated with coal-tar sealcoat were a major source of PAH compounds in streams. This report presents methods for and data from the analysis of concentrations of PAH compounds in dust from sealed and unsealed pavement from nine U.S. cities, and concentrations of PAH compounds in other related solid materials (sealcoat surface scrapings, nearby street dust, and nearby soil) from three of those same cities and a 10th city. Dust samples were collected by sweeping dust from areas of several square meters with a soft nylon brush into a dustpan. Some samples were from individual lots or driveways, and some samples consisted of approximately equal amounts of material from three lots. Samples were sieved to remove coarse sand and gravel and analyzed by gas chromatography/mass spectrometry. Concentrations of PAHs vary greatly among samples with total PAH (sigmaPAH), the sum of 12 unsubstituted parent PAHs, ranging from nondetection for all 12 PAHs (several samples from Portland, Oregon, and Seattle, Washington; sigmaPAH of less than 36,000 micrograms per kilogram) to 19,000,000 micrograms per kilogram for a sealcoat scraping sample (Milwaukee, Wisconsin). The largest PAH concentrations in dust are from a driveway sample from suburban Chicago, Illinois (sigmaPAH of 9,600,000 micrograms per kilogram).

  3. Analysis of "Midnight" Tracks in the Stardust Interstellar Dust Collector: Possible Discovery of a Contemporary Interstellar Dust Grain

    Science.gov (United States)

    Westphal, A. J.; Allen, C.; Bajit, S.; Bastien, R.; Bechtel, H.; Bleuet, P.; Borg, J.; Brenker, F.; Bridges, J.; Brownlee, D. E.; hide

    2010-01-01

    In January 2006, the Stardust sample return capsule returned to Earth bearing the first solid samples from a primitive solar system body, Comet 81P/Wild2, and a collector dedicated to the capture and return of contemporary interstellar dust. Both collectors were approximately 0.1m(exp 2) in area and were composed of aerogel tiles (85% of the collecting area) and aluminum foils. The Stardust Interstellar Dust Collector (SIDC) was exposed to the interstellar dust stream for a total exposure factor of 20 m(exp 2) day. The Stardust Interstellar Preliminary Examination (ISPE) is a three-year effort to characterize the collection using nondestructive techniques.

  4. Influences of gas stream conditions on efficiency of tritiated moisture collection with P2O5-desiccant and isotope effect

    International Nuclear Information System (INIS)

    Kotoh, Kenji; Miura, Katsuya; Kashio, Yousuke; Nishikawa, Masabumi

    1991-01-01

    A method was proposed previously for collection and measurement of tritiated moisture in gas stream using P 2 O 5 -desiccant. Influences of the gas humidity, the gas flow rate and the distance between gas nozzle and P 2 O 5 -desiccant layer surface on the moisture collection efficiency have been examined through experiments, and the isotope effect on the collection has been investigated. The collection efficiency is the ratio of collected to supplied moisture, and the moisture supplying rate is in proportion to the humidity and flow rate of feed gas. The experiments show that; the collection efficiency dose not depend on the gas humidity, but is affected by the gas flow rate and by the nozzle-layer distance. The effects of the flow rate and the nozzle position are related to the mass transfer distance from the bulk of gas stream to the desiccant layer surface in the collection cell. The moisture collecting rate is promoted by the approach of the gas stream to the layer surface. An expression of effective separation factor has been derived to explain the isotope effect on the moisture collection. Experimental data distribution of the separation factor have been reasonably simulated by the analysis. (author)

  5. Analysis of Dust Samples Collected from an Unused Spent Nuclear Fuel Interim Storage Container at Hope Creek, Delaware.

    Energy Technology Data Exchange (ETDEWEB)

    Bryan, Charles R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Enos, David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-03-01

    In July, 2014, the Electric Power Research Institute and industry partners sampled dust on the surface of an unused canister that had been stored in an overpack at the Hope Creek Nuclear Generating Station for approximately one year. The foreign material exclusion (FME) cover that had been on the top of the canister during storage, and a second recently - removed FME cover, were also sampled. This report summarizes the results of analyses of dust samples collected from the unused Hope Creek canister and the FME covers. Both wet and dry samples of the dust/salts were collected, using SaltSmart(TM) sensors and Scotch - Brite(TM) abrasive pads, respectively. The SaltSmart(TM) samples were leached and the leachate analyzed chemically to determine the composition and surface load per unit area of soluble salts present on the canister surface. The dry pad samples were analyzed by X-ray fluorescence and by scanning electron microscopy to determine dust texture and mineralogy; and by leaching and chemical analysis to deter mine soluble salt compositions. The analyses showed that the dominant particles on the canister surface were stainless steel particles, generated during manufacturing of the canister. Sparse environmentally - derived silicates and aluminosilicates were also present. Salt phases were sparse, and consisted of mostly of sulfates with rare nitrates and chlorides. On the FME covers, the dusts were mostly silicates/aluminosilicates; the soluble salts were consistent with those on the canister surface, and were dominantly sulfates. It should be noted that the FME covers were w ashed by rain prior to sampling, which had an unknown effect of the measured salt loads and compositions. Sulfate salts dominated the assemblages on the canister and FME surfaces, and in cluded Ca - SO4 , but also Na - SO4 , K - SO4 , and Na - Al - SO4 . It is likely that these salts were formed by particle - gas conversion reactions, either

  6. Quantifying in-stream nitrate reaction rates using continuously-collected water quality data

    Science.gov (United States)

    Matthew Miller; Anthony Tesoriero; Paul Capel

    2016-01-01

    High frequency in situ nitrate data from three streams of varying hydrologic condition, land use, and watershed size were used to quantify the mass loading of nitrate to streams from two sources – groundwater discharge and event flow – at a daily time step for one year. These estimated loadings were used to quantify temporally-variable in-stream nitrate processing ...

  7. Shearer-mounted dust collection: evaluation of ventilated cutting drums. Open File Report (Final)

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, J.S.; Muldoon, T.L.

    1987-06-01

    Effective control of respirable dust is one of the most serious problems associated with longwall mining in the United States. This report describes the development and the underground evaluation of ventilated cutting drums, on a double ended ranging-drum shearer. The ventilated drum uses high pressure (1500 psi) water sprays to draw air (3500 cfm) through 12 airmoving tubes mounted in the drum hub. The sprays draw dusty air from the face side of the drum, scrub the air, and discharge the clean air on the gob side of the drum against a deflector plate. During a three-week underground evaluation, the cutting drums reduced shearer-generated dust levels at the shearer operators position by 40%, at the shield operators downwind of the shearer by 55%, and at the tailgate by 55%. Cutting and loading performance of the drums were superior to the mine's conventional drums. After the evaluation, the mine continued to use the ventilated drums to finish mining the panel.

  8. Evaluation of Measurements Collected with Multi-Parameter Continuous Water-Quality Monitors in Selected Illinois Streams, 2001-03

    Science.gov (United States)

    Groschen, George E.; King, Robin B.

    2005-01-01

    Eight streams, representing a wide range of environmental and water-quality conditions across Illinois, were monitored from July 2001 to October 2003 for five water-quality parameters as part of a pilot study by the U.S. Geological Survey (USGS) in cooperation with the Illinois Environmental Protection Agency (IEPA). Continuous recording multi-parameter water-quality monitors were installed to collect data on water temperature, dissolved-oxygen concentrations, specific conductivity, pH, and turbidity. The monitors were near USGS streamflow-gaging stations where stage and streamflow are continuously recorded. During the study period, the data collected for these five parameters generally met the data-quality objectives established by the USGS and IEPA at all eight stations. A similar pilot study during this period for measurement of chlorophyll concentrations failed to achieve the data-quality objectives. Of all the sensors used, the temperature sensors provided the most accurate and reliable measurements (generally within ?5 percent of a calibrated thermometer reading). Signal adjustments and calibration of all other sensors are dependent upon an accurate and precise temperature measurement. The dissolved-oxygen sensors were the next most reliable during the study and were responsive to changing conditions and accurate at all eight stations. Specific conductivity was the third most accurate and reliable measurement collected from the multi-parameter monitors. Specific conductivity at the eight stations varied widely-from less than 40 microsiemens (?S) at Rayse Creek near Waltonville to greater than 3,500 ?S at Salt Creek at Western Springs. In individual streams, specific conductivity often changed quickly (greater than 25 percent in less than 3 hours) and the sensors generally provided good to excellent record of these variations at all stations. The widest range of specific-conductivity measurements was in Salt Creek at Western Springs in the Greater Chicago

  9. A detailed characterization of the Saharan dust collected during the Fennec campaign in 2011: in situ ground-based and laboratory measurements

    Science.gov (United States)

    Rocha-Lima, Adriana; Vanderlei Martins, J.; Remer, Lorraine A.; Todd, Martin; Marsham, John H.; Engelstaedter, Sebastian; Ryder, Claire L.; Cavazos-Guerra, Carolina; Artaxo, Paulo; Colarco, Peter; Washington, Richard

    2018-01-01

    Millions of tons of mineral dust are lifted by the wind from arid surfaces and transported around the globe every year. The physical and chemical properties of the mineral dust are needed to better constrain remote sensing observations and are of fundamental importance for the understanding of dust atmospheric processes. Ground-based in situ measurements and in situ filter collection of Saharan dust were obtained during the Fennec campaign in the central Sahara in 2011. This paper presents results of the absorption and scattering coefficients, and hence single scattering albedo (SSA), of the Saharan dust measured in real time during the last period of the campaign and subsequent laboratory analysis of the dust samples collected in two supersites, SS1 and SS2, in Algeria and in Mauritania, respectively. The samples were taken to the laboratory, where their size and aspect ratio distributions, mean chemical composition, spectral mass absorption efficiency, and spectral imaginary refractive index were obtained from the ultraviolet (UV) to the near-infrared (NIR) wavelengths. At SS1 in Algeria, the time series of the scattering coefficients during the period of the campaign show dust events exceeding 3500 Mm-1, and a relatively high mean SSA of 0.995 at 670 nm was observed at this site. The laboratory results show for the fine particle size distributions (particles diameter  dust collected in Algeria and 0.008 to 0.002i for dust collected in Mauritania over the wavelength range of 350-2500 nm. Differences in the mean elemental composition of the dust collected in the supersites in Algeria and in Mauritania and between fine and mixed particle size distributions were observed from EDXRF measurements, although those differences cannot be used to explain the optical properties variability between the samples. Finally, particles with low-density typically larger than 10 µm in diameter were found in some of the samples collected at the supersite in Mauritania, but these

  10. Analysis of Dust Samples Collected from an In-Service Interim Storage System at the Maine Yankee Nuclear Site.

    Energy Technology Data Exchange (ETDEWEB)

    Bryan, Charles R.; Enos, David

    2016-10-01

    In July, 2016, the Electric Power Research Institute and industry partners performed a field test at the Maine Yankee Nuclear Site, located near Wiscasset, Maine. The primary goal of the field test was to evaluate the use of robots in surveying the surface of an in-service interim storage canister within an overpack; however, as part of the demonstration, dust and soluble salt samples were collected from horizontal surfaces within the interim storage system. The storage system is a vertical system made by NAC International, consisting of a steel-lined concrete overpack containing a 304 stainless steel (SS) welded storage canister. The canister did not contain spent fuel but rather greater-than-class-C waste, which did not generate significant heat, limiting airflow through the storage system. The surfaces that were sampled for deposits included the top of the shield plug, the side of the canister, and a shelf at the bottom of the overpack, just below the level of the pillar on which the canister sits. The samples were sent to Sandia National Laboratories for analysis. This report summarizes the results of those analyses. Because the primary goal of the field test was to evaluate the use of robots in surveying the surface of the canister within the overpack, collection of dust samples was carried out in a qualitative fashion, using paper filters and sponges as the sampling media. The sampling focused mostly on determining the composition of soluble salts present in the dust. It was anticipated that a wet substrate would more effectively extract soluble salts from the surface that was sampled, so both the sponges and the filter paper were wetted prior to being applied to the surface of the metal. Sampling was accomplished by simply pressing the damp substrate against the metal surface for two minutes, and then removing it. It is unlikely that the sampling method quantitatively collected dust or salts from the metal surface; however, both substrates did extract a

  11. An Evaluation of Data Collected by Middle School and College-Level Students in Stream Channel Geomorphic Assessment

    Directory of Open Access Journals (Sweden)

    Martin D. Lafrenz

    2013-01-01

    Full Text Available This project tested the accuracy and repeatability of geomorphic stream channel assessments conducted by two different middle school classes from the Walt Morey Middle School in Troutdale, OR and college students from Portland State University in Portland, OR. Each group surveyed the same three cross-sections in Fairview Creek, a tributary to the Lower Columbia River, in order to assess stream channel geometry, discharge, composition of the bed material, and water quality. The three student groups were all able to accurately document the stream channel geometry, including stream width and mean depth, indicating that these data can be successfully collected by volunteers of various ages. However, stream velocity obtained using the float method was consistently overestimated leading to a biased calculation of discharge, and the low precision of the measurements did not allow for a correction of the bias. The median particle size of the bed material determined by a pebble count was also overestimated by each group, but the low precision also negated the possibility of correcting the estimate. The stored fine sediment in the bed was underestimated by each group and again with low precision. The temperature, pH, and conductivity measured with a calibrated multimeter were accurate and precise for all groups.

  12. 78 FR 25308 - Proposed Collection; Comment Request; Coal Mine Dust Sampling Devices

    Science.gov (United States)

    2013-04-30

    ... provided in the desired format, reporting burden (time and financial resources) is minimized, collection... agencies with an opportunity to comment on proposed and continuing collections of information in accordance..., 2013. ADDRESSES: Comments concerning the information collection requirements of this notice must be...

  13. Macrocyclic-, polycyclic-, and nitro musks in cosmetics, household commodities and indoor dusts collected from Japan: implications for their human exposure.

    Science.gov (United States)

    Nakata, Haruhiko; Hinosaka, Mari; Yanagimoto, Hayato

    2015-01-01

    This paper reported the occurrence and concentrations of macrocyclic-, polycyclic- and nitro musks in cosmetics and household commodities collected from Japan. The high concentrations and detection frequencies of Musk T, habanolide, and exaltolides were found in commercial products, suggesting their large amounts of production and usage in Japan. Polycyclic musks, HHCB and OTNE, also showed high concentrations in cosmetics and products. The estimated dairy intakes of Musk T and HHCB by the dermal exposure to commercial products were 7.8 and 7.9 μg/kg/day in human, respectively, and perfume and body lotion are dominant exposure sources. We also analyzed synthetic musks in house dusts. Polycyclic musks, HHCB and OTNE, showed high concentrations in samples, but macrocyclic musks were detected only in a few samples, although these types of musks were highly detected in commercial products. This is probably due to easy-degradation of macrocyclic musks in indoor environment. The dairy intakes of HHCB by dust ingestions were 0.22 ng/kg/day in human, which were approximately five orders of magnitudes lower than those of dermal absorption from commercial household commodities. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Water quality in Pearl Harbor and feeder streams during 1971 - 2001 collected primarily by oceanography students from Leeward Community College (NODC Accession 0000590)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water quality data were collected in Pearl Harbor and surrounding feeder streams from 30 December 1971 to 24 August 2001. Data were collected by Leeward Community...

  15. The dust that lights up the Zodiac

    International Nuclear Information System (INIS)

    Dixon, D.; McDonnell, T.; Carey, B.

    1985-01-01

    The article concerns cosmic dust particles, which vary in size from fine dust to large dust particles which burn-up in the atmosphere as meteors. The composition and properties of cosmic dust; zodiacal light; brownlee particles; capture cell for collecting dust samples in space and hypervelocity impacts of cosmic dust on the cell; are all discussed. (U.K.)

  16. Comparison of organic compositions in dust storm and normal aerosol samples collected at Gosan, Jeju Island, during spring 2005

    Science.gov (United States)

    Wang, Gehui; Kawamura, Kimitaka; Lee, Meehye

    To better understand the current physical and chemical properties of East Asian aerosols, an intensive observation of atmospheric particles was conducted at Gosan site, Jeju Island, South Korea during 2005 spring. Total suspended particle (TSP) samples were collected using pre-combusted quartz filters and a high-volume air sampler with the time intervals ranging from 3 h to 48 h. The kinds and amount of various organic compounds were measured in the samples using gas chromatography-mass spectrometry. Among the 99 target compounds detected, saccharides (average, 130 ± 14 ng m -3), fatty acids (73 ± 7 ng m -3), alcohols (41 ± 4 ng m -3), n-alkanes (32 ± 3 ng m -3), and phthalates (21 ± 2 ng m -3) were found to be major compound classes with polyols/polyacids, lignin and resin products, PAHs, sterols and aromatic acids being minor. Compared to the previous results reported for 2001 late spring samples, no significant changes were found in the levels of their concentrations and compositions for 4 years, although the economy in East Asia, especially in China, has sharply expanded from 2001 to 2005. During the campaign at Gosan site, we encountered two distinct dust storm episodes with high TSP concentrations. The first dust event occurred on March 28, which was characterized by a predominance of secondary organic aerosols. The second event that occurred on the next day (March 29) was found to be characterized by primary organic aerosols associated with forest fires in Siberia/northeastern China. A significant variation in the molecular compositions, which was found within a day, suggests that the compositions of East Asian aerosols are heterogeneous due to multi-contributions from different source regions together with different pathways of long-range atmospheric transport of particles.

  17. Building an Entity-Centric Stream Filtering Test Collection for TREC 2012

    Science.gov (United States)

    2012-11-01

    consecutive hours from October 2011 through April 2012. It contains over 400M documents, which we augmented with named entity classification...CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING...than IR. We also constructed an entirely new stream corpus spanning 4,973 consecutive hours from October 2011 through April 2012. It contains over 400M

  18. Three-dimensional wake potential in a streaming dusty plasma

    Indian Academy of Sciences (India)

    frequency and low-phase-velocity dust-acoustic mode is the origin of the periodic attractive force between the like polarity particulates along and perpendicular to the streaming ions and dust grains resulting into dust-Coulomb crystal formation.

  19. Chemical Characterization and Behavior of Respirable Fractions of Indoor Dusts Collected Near a Landfill Facility

    Directory of Open Access Journals (Sweden)

    Rheo B. Lamorena-Lim

    2016-06-01

    Full Text Available The study aims to determine the inorganic and organic phases in airborne particulate matter (PM collected near a landf ill facility. The establishments within the vicinity of the landfill considered in the study were a junk shop, a school, and a money changer shop. From the elemental analysis using inductively-coupled plasma mass spectrometry (ICP-MS, lead and cadmium were discovered to be more abundant in the total suspended particulate (TSP fraction, whereas copper was more abundant in the smaller PM2.5. Manganese, arsenic, strontium, cadmium, and lead were more abundant in the PM10 fraction than in PM2.5. The results of the chemical characterization were compiled and evaluated in a geochemical modelling code (PHREEQC to determine the potential speciation of these chemical constituents. Solution complexes of As, Pb, Cd and phthalates, and metal species, such as H2AsO3- , Cd2OH3+, Pb(OH3-, were predicted to form by the PHREEQC simulation runs once the endmember components interact with water. The results contribute to the background information on the potential impacts from exposure to airborne PM at workplaces around landfill facilities. Moreover, the data gathered provide a baseline for the chemical characterization and behavior of chemical constituents of PM possibly present in this specific type of environment.

  20. Comparison of coarse coal dust sampling techniques in a laboratory-simulated longwall section.

    Science.gov (United States)

    Patts, Justin R; Barone, Teresa L

    2017-05-01

    Airborne coal dust generated during mining can deposit and accumulate on mine surfaces, presenting a dust explosion hazard. When assessing dust hazard mitigation strategies for airborne dust reduction, sampling is done in high-velocity ventilation air, which is used to purge the mining face and gallery tunnel. In this environment, the sampler inlet velocity should be matched to the air stream velocity (isokinetic sampling) to prevent oversampling of coarse dust at low sampler-to-air velocity ratios. Low velocity ratios are often encountered when using low flow rate, personal sampling pumps commonly used in underground mines. In this study, with a goal of employing mine-ready equipment, a personal sampler was adapted for area sampling of coarse coal dust in high-velocity ventilation air. This was done by adapting an isokinetic nozzle to the inlet of an Institute of Occupational Medicine (Edinburgh, Scotland) sampling cassette (IOM). Collected dust masses were compared for the modified IOM isokinetic sampler (IOM-MOD), the IOM without the isokinetic nozzle, and a conventional dust sampling cassette without the cyclone on the inlet. All samplers were operated at a flow rate typical of personal sampling pumps: 2 L/min. To ensure differences between collected masses that could be attributed to sampler design and were not influenced by artifacts from dust concentration gradients, relatively uniform and repeatable dust concentrations were demonstrated in the sampling zone of the National Institute for Occupational Safety and Health experimental mine gallery. Consistent with isokinetic theory, greater differences between isokinetic and non-isokinetic sampled masses were found for larger dust volume-size distributions and higher ventilation air velocities. Since isokinetic sampling is conventionally used to determine total dust concentration, and isokinetic sampling made a difference in collected masses, the results suggest when sampling for coarse coal dust the IOM-MOD may

  1. A detailed characterization of the Saharan dust collected during the Fennec campaign in 2011: in situ ground-based and laboratory measurements

    Directory of Open Access Journals (Sweden)

    A. Rocha-Lima

    2018-01-01

    Full Text Available Millions of tons of mineral dust are lifted by the wind from arid surfaces and transported around the globe every year. The physical and chemical properties of the mineral dust are needed to better constrain remote sensing observations and are of fundamental importance for the understanding of dust atmospheric processes. Ground-based in situ measurements and in situ filter collection of Saharan dust were obtained during the Fennec campaign in the central Sahara in 2011. This paper presents results of the absorption and scattering coefficients, and hence single scattering albedo (SSA, of the Saharan dust measured in real time during the last period of the campaign and subsequent laboratory analysis of the dust samples collected in two supersites, SS1 and SS2, in Algeria and in Mauritania, respectively. The samples were taken to the laboratory, where their size and aspect ratio distributions, mean chemical composition, spectral mass absorption efficiency, and spectral imaginary refractive index were obtained from the ultraviolet (UV to the near-infrared (NIR wavelengths. At SS1 in Algeria, the time series of the scattering coefficients during the period of the campaign show dust events exceeding 3500 Mm−1, and a relatively high mean SSA of 0.995 at 670 nm was observed at this site. The laboratory results show for the fine particle size distributions (particles diameter  < 5µm and mode diameter at 2–3 µm in both sites a spectral dependence of the imaginary part of the refractive index Im(m with a bow-like shape, with increased absorption in UV as well as in the shortwave infrared. The same signature was not observed, however, in the mixed particle size distribution (particle diameter  < 10 µm and mode diameter at 4 µm in Algeria. Im(m was found to range from 0.011 to 0.001i for dust collected in Algeria and 0.008 to 0.002i for dust collected in Mauritania over the wavelength range of 350–2500

  2. Protocol for collecting eDNA samples from streams [Version 2.3

    Science.gov (United States)

    K. J. Carim; T. Wilcox; M. K. Young; K. S. McKelvey; M. K. Schwartz

    2015-01-01

    Throughout the 2014 field season, we had over two dozen biologist throughout the western US collect over 300 samples for eDNA analysis with paired controls. Control samples were collected by filtering 0.5 L of distilled water. No samples had any evidence of field contamination. This method of sampling verifies the cleanliness of the field equipment, as well as the...

  3. Typology of dust particles collected by the COSIMA mass spectrometer in the inner coma of 67P/Churyumov Gerasimenko from Rendez-Vous to perihelion.

    Science.gov (United States)

    Langevin, Y.; Hilchenbach, M.; Ligier, N.; Merouhane, S.; Hornung, K.

    2015-10-01

    COSIMA is a TOF/SIMS spectrometer dedicated to the analysis of cometary grains collected insitu on the the Rosetta orbiter. The grains are collected on targets 10 mm x 10 mm in area exposed by sets of 3("target assembly") in front of a funnel providing a 20° x 40° FOV to the outside environment of the spacecraft. 4 target assemblies have been exposed from August 8th 2014 (distant approach phase) to April 29th, 2015 on a weekly basis, except during near comet passages (daily basis). 10 of the 12 targets exposed up to now are covered by "metal black" layers (gold or silver) so as to maximize grain collection efficiency [1], the other two targets being silver foils. The collected grains are detected by a microscope, COSISCOPE, using two LED's at grazing incidence and a 14 μm pixel size (714 pixels across the target). This set up was designed so as not to miss the small particles expected to dominate the distribution of collected dust as well as the imprints resulting from rebounding particles when simulating impacts at speeds of up to 300 m/s as predicted by models of the inner coma [2]. The number and size of collected particles far exceeded expectations, with more than 10000 identified particles, including more than 80 collected dust particles with sizes of 7 pixels (100 μm) or more, making it possible to characterize the diversity of cometary grains collected in-situ at very low velocities in the inner coma of 67P/Churyumov-Gerasimenko. The first results demonstrated that cometary dust close to the nucleus is dominated by fluffy aggregates [3]. At EPSC, we will present the results on the pre-perihelion phase (August 2014 to August 2015).

  4. Levoglucosan and Lipid Class Compounds in the Asian Dusts and Marine Aerosols Collected During the ACE-Asia Campaign

    Science.gov (United States)

    Kobayashi, M.; Simoneit, B. R.; Kawamura, K.; Mochida, M.; Lee, M.; Lee, G.; Huebert, B. J.

    2002-12-01

    In order to characterize organic aerosols in the Asian Pacific region, we collected filter samples at Gosan (formerly Kosan) and Sapporo sites as well as on mobile platforms (R.V. R.H. Brown and NCAR C-130) in the western North Pacific. The aerosol extracts were analyzed by capillary GC-MS employing a TMS derivatization technique. We identified over 100 organic compounds in the samples. They are categorized into seven different classes in terms of functional groups and sources. First, sugar-type compounds were detected in the aerosols, including levoglucosan, galactosan and mannosan, which are tracers for biomass burning. Second, a homologous series of fatty acids (C12-C30) and fatty alcohols (C12-C30) mainly from plant waxes and marine lipids were present. The third group includes dicarboxylic acids (>C3) and other atmospheric oxidation products. Although oxalic (C2) and malonic (C3) acids were not detected by this method, they are very abundant in the aerosols. The fourth group includes n-alkanes (C18-C35) which usually showed a strong odd/even predominance, suggesting an important contribution from higher plant waxes. The fifth includes polynuclear aromatic hydrocarbons (PAH) ranging from phenanthrene to coronene, all combustion products of petroleum and mainly coal. Saccharides were the sixth group and consisted mainly of a- and b- glucose, sucrose and its alditol, and minor amounts of xylitol, sorbitol and arabitol. These saccharides are tracers for soil dust. Phthalates were detected as the seventh class, with a dominance of dioctyl phthalate. The results suggest that organic aerosols originate primarily from (1) natural emissions of terrestrial plant wax and marine lipids, (2) smoke from biomass burning (mainly non-conifer fuels), (3) soil resuspension due to spring agricultural activity, (4) urban/industrial emissions from fossil fuel use (coal), and (5) secondary reaction products. These compounds are transported by the strong westerly winds and therefore

  5. Quantifying the Source and in-Stream Gain/Loss of Nitrate Using Continuously-Collected Water Quality Data

    Science.gov (United States)

    Miller, M. P.; Tesoriero, A. J.; Capel, P.

    2014-12-01

    High frequency in situ nitrate data from three streams spanning gradients in hydrologic conditions, land use, and watershed size were used to quantify the mass loading of nitrate to streams from two sources - groundwater discharged and event flow nitrate - at a daily time step for one year. Temporal variability in net in-stream loss or production of nitrate and environmental controls on nitrate processing were also quantified. Nitrate in groundwater discharge was identified as contributing approximately 70% of the total nitrate load to a large river and small agricultural stream, compared with 45% to a small urban stream. The greatest in-stream losses of nitrate occurred during the summer and fall months, with net in-stream losses of up to 70% of total nitrate load in the large river, 60% in the agricultural stream, and 50% in the urban stream. Photosynthetically active radiation was identified as the most likely mechanism of in-stream nitrate loss in the large river, whereas baseflow discharge and temperature were the most likely mechanisms of nitrate loss in the small agricultural and urban streams, respectively. As more high frequency nitrate data become available, the approach described here can be applied to further understand nitrate sources to streams and controls on in-stream nitrate production and retention.

  6. Origin of fine dust in urban environmental zones--Evidence from element patterns received by dichotomous collection and INAA.

    Science.gov (United States)

    Weckwerth, G

    2010-10-01

    In order to fulfil the EU-limitations of fine dust and traffic-produced gases Cologne installed 2008 one of the first German environmental zones, from which stepwise vehicles with too high emissions will be locked out. Verification of effectiveness and the research on further strategies to reduce fine dust are studied as promising applications of a method on discrimination of aerosol components from different origins (Weckwerth, 2001). New measurements in Cologne gave several implications on supports, especially in connection with traffic abrasion from brakes, tires and rails. Copyright 2010. Published by Elsevier Ltd.

  7. Navigating the Flow of Value Streams to the Seas of Collection Management, Acquisitions, and Preservation

    OpenAIRE

    Voelker, Greg W.; Zwiercan, Richard J. W.; Frazier, Michael

    2014-01-01

    Our process of repairing damaged items had no clear ownership and an ever growing amorphous backlog consisting of approximately 2,800 items at the start of the process review. This backlog continues to hinder access to materials in the collection. We are currently in multistage process review which incorporates Lean methodologies to improve workflow across a number of departments. At the core of these improvements is gathering data to measure current levels of work. From that perspective, we ...

  8. Household vacuum cleaners vs. the high-volume surface sampler for collection of carpet dust samples in epidemiologic studies of children

    Directory of Open Access Journals (Sweden)

    Buffler Patricia A

    2008-02-01

    Full Text Available Abstract Background Levels of pesticides and other compounds in carpet dust can be useful indicators of exposure in epidemiologic studies, particularly for young children who are in frequent contact with carpets. The high-volume surface sampler (HVS3 is often used to collect dust samples in the room in which the child had spent the most time. This method can be expensive and cumbersome, and it has been suggested that an easier method would be to remove dust that had already been collected with the household vacuum cleaner. However, the household vacuum integrates exposures over multiple rooms, some of which are not relevant to the child's exposure, and differences in vacuuming equipment and practices could affect the chemical concentration data. Here, we compare levels of pesticides and other compounds in dust from household vacuums to that collected using the HVS3. Methods Both methods were used in 45 homes in California. HVS3 samples were collected in one room, while the household vacuum had typically been used throughout the home. The samples were analyzed for 64 organic compounds, including pesticides, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls (PCBs, using GC/MS in multiple ion monitoring mode; and for nine metals using conventional microwave-assisted acid digestion combined with ICP/MS. Results The methods agreed in detecting the presence of the compounds 77% to 100% of the time (median 95%. For compounds with less than 100% agreement, neither method was consistently more sensitive than the other. Median concentrations were similar for most analytes, and Spearman correlation coefficients were 0.60 or higher except for allethrin (0.15 and malathion (0.24, which were detected infrequently, and benzo(kfluoranthene (0.55, benzo(apyrene (0.55, PCB 105 (0.54, PCB 118 (0.54, and PCB 138 (0.58. Assuming that the HVS3 method is the "gold standard," the extent to which the household vacuum cleaner method yields relative risk

  9. Cosmic Dust Catalog

    Data.gov (United States)

    National Aeronautics and Space Administration — Since May 1981, the National Aeronautics and Space Administration (NASA) has used aircraft to collect cosmic dust (CD) particles from Earth's stratosphere. Specially...

  10. Economics of wood dust

    Energy Technology Data Exchange (ETDEWEB)

    Kaiser, J.A.

    1980-11-01

    This article reviews the economic effects of wood dust. The most important use of wood today is a fuel, and wood chips and shavings are sources of feedstock for boilers. Other uses include wood chips in the manufacture of particleboard, wood dust as bedding in riding stables and race tracks, as mulch for florists, and as an absorbent in the meat packing industry. The installation of dust collection systems is strongly urged as the consequences of inadequate collection include rapid machine wear, poor environmental conditions for workers, general interference with work, and its combustibility makes it a constant fire hazard.

  11. Solar wind magnetic field bending of Jovian dust trajectories.

    Science.gov (United States)

    Zook, H A; Grün, E; Baguhl, M; Hamilton, D P; Linkert, G; Liou, J; Forsyth, R; Phillips, J L

    1996-11-29

    From September 1991 to October 1992, the cosmic dust detector on the Ulysses spacecraft recorded 11 short bursts, or streams, of dust. These dust grains emanated from the jovian system, and their trajectories were strongly affected by solar wind magnetic field forces. Analyses of the on-board measurements of these fields, and of stream approach directions, show that stream-associated dust grain masses are of the order of 10(-18) gram and dust grain velocities exceed 200 kilometers per second. These masses and velocities are, respectively, about 10(3) times less massive and 5 to 10 times faster than earlier reported.

  12. Whither Cometary Dust?

    Science.gov (United States)

    Lisse, Carey M.

    2010-10-01

    In this paper I will discuss recent findings that have important implications for our understanding of the formation and evolution of primitive solar system dust, including: - Nesvorny et al. (2010), following up on their dynamical analyses of the zodiacal dust bands as sourced by the breakup of the Karin (5Mya) and Veritas (8Mya) asteroid families, argue that over 90% of the interplanetary dust cloud at 1 AU comes from JFC comets with near-circularized, low inclination orbits. This implies that the noted IPD collections of anhydrous and hydrous dust particles are likely to be from Oort cloud and JFC comets, respectively, not from asteroids and comets as thought in the past. Hydrous dust particles from comets like 85P/Wild2 and 9P/Tempel 1 would be consistent with results from the STARDUST and Deep Impact experiments. - Estimates of the dust particle size distributions (PSDs) in the comae of 85P/Wild2 (Green et al. 2004, 2007) and 73P/SW-3 (Sitko et al. 2010, Vaubaillon & Reach 2010) and in the trails of comets (Reach et al. 2007) have broken power law structure, with a plateau enhancement of particles of 1 mm - 1 cm in size. This size is also the size of most chondritic inclusions, and the predicted size range of the "aggregational barrier", where collisions between dust particles become destructive. - Studies of the albedo and polarization properties of cometary dust (Kolokolova et al. 2007) suggest there are 2 major groupings, one with low scattering capability and one with high. While these families could possibly have been explained by systematics in the PSDs of the emitted dust, independent work by Lisse et al. (2008) on the mineralogy of a number of highly dusty comets has shown evidence for one family of comets with highly crystalline dust and another with highly amorphous dust.

  13. Wood Dust

    Science.gov (United States)

    Learn about wood dust, which can raise the risk of cancers of the paranasal sinuses and nasal cavity. High amounts of wood dust are produced in sawmills, and in the furniture-making, cabinet-making, and carpentry industries.

  14. Raising Dust

    Science.gov (United States)

    2004-01-01

    21 December 2003Dust storms are a common occurrence on the extremely arid planet, Mars. However, very rarely do we get to see the actual process of dust being lifted off the martian surface to feed these dust storms. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image captures some of the dust-raising process in action. The picture shows a shallow trough with large, ripple-like dunes on its floor. Sunlight illuminates the scene from the upper left. Puffy, billowy clouds of dust obscure some of the surface from view. Closer inspection shows streamers of dust, streaking from left/upper left toward right/lower right, down near the surface of the planet. It is in these streamers that dust is being lifted from the ground. This image is located near 29.6oS, 73.1oW, and covers an area 3 km (1.9 mi) wide.

  15. Ulysses dust measurements near Jupiter.

    Science.gov (United States)

    Grün, E; Zook, H A; Baguhl, M; Fechtig, H; Hanner, M S; Kissel, J; Lindblad, B A; Linkert, D; Linkert, G; Mann, I B

    1992-09-11

    Submicrometer- to micrometer-sized particles were recorded by the Ulysses dust detector within 40 days of the Jupiter flyby. Nine impacts were recorded within 50 Jupiter radii with most of them recorded after closest approach. Three of these impacts are consistent with particles on prograde orbits around Jupiter and the rest are believed to have resulted from gravitationally focused interplanetary dust. From the ratio of the impact rate before the Jupiter flyby to the impact rate after the Jupiter flyby it is concluded that interplanetary dust particles at the distance of Jupiter move on mostly retrograde orbits. On 10 March 1992, Ulysses passed through an intense dust stream. The dust detector recorded 126 impacts within 26 hours. The stream particles were moving on highly inclined and apparently hyperbolic orbits with perihelion distances of >5 astronomical units. Interplanetary dust is lost rather quickly from the solar system through collisions and other mechanisms and must be almost continuously replenished to maintain observed abundances. Dust flux measurements, therefore, give evidence of the recent rates of production from sources such as comets, asteroids, and moons, as well as the possible presence of interstellar grains.

  16. Difference in Pro-Inflammatory Cytokine Responses Induced in THP1 Cells by Particulate Matter Collected on Days with and without ASIAN Dust Storms

    Directory of Open Access Journals (Sweden)

    Masanari Watanabe

    2015-07-01

    Full Text Available The associations between particulate matter from Asian dust storms (ADS and health disorders differ among studies, and the underlying mechanisms remain unclear. In this study, ADS and non-ADS particles were tested for their potential to induce pro-inflammatory cytokines associated with adverse respiratory effects. Particulate matter was collected in Japan during four periods in 2013 (2 × ADS periods; 2 × non-ADS. THP1 cells were exposed to this particulate matter, and the levels of various interleukins (ILs, and tumor necrosis factor (TNF-α were measured. Levels of IL-2 increased significantly following exposure to all particulate matter samples (compared to levels in a solvent control. Increased levels of IL-10 and TNF-α were also observed following exposure to particles collected during three (one ADS and two non-ADS and two (one ADS and one non-ADS collection periods, respectively. Thus, the effects of particulate matter on cytokine responses differed according to collection period, and the effects of ADS particles differed for each ADS event. Additionally, the levels of pro-inflammatory cytokines induced by ADS particles were not always higher than those induced by non-ADS particles.

  17. FTIR Analysis of Aerogel Keystones from the Stardust Interstellar Dust Collector: Assessment of Terrestrial Organic Contamination and X-Ray Microprobe Beam Damage

    Science.gov (United States)

    Zolensky, M. E.; Bechtel, H. A.; Allen, C.; Bajt, S.; Borg, J.; Brenker, F.; Bridges, J.; Brownlee, D. E.; Burchell, M.; Burghammer, M.; hide

    2011-01-01

    The Stardust Interstellar Dust Collector (SIDC) was intended to capture and return contemporary interstellar dust. The approx.0.1 sq m collector was composed of aerogel tiles (85% of the collecting area) and aluminum foils and was exposed to the interstellar dust stream for a total exposure factor of 20 sq m day. The Stardust Interstellar Preliminary Examination (ISPE) is a consortium-based project to characterize the collection using nondestructive techniques. Sandford et al. recently assessed numerous potential sources of organic contaminants in the Stardust cometary collector. These contaminants could greatly complicate the analysis and interperetation of any organics associated with interstellar dust, particularly because signals from these particles are expected to be exceedingly small. Here, we present a summary of FTIR analyses of over 20 aerogel keystones, many of which contained candidates for interstellar dust.

  18. Electron microscopy of particles collected at Praia, Cape Verde, during the Saharan Mineral Dust Experiment: particle chemistry, shape, mixing state and complex refractive index

    Science.gov (United States)

    Kandler, K.; Lieke, K.; Benker, N.; Emmel, C.; Küpper, M.; Müller-Ebert, D.; Ebert, M.; Scheuvens, D.; Schladitz, A.; Schütz, L.; Weinbruch, S.

    2011-09-01

    A large field experiment of the Saharan Mineral Dust Experiment (SAMUM) was performed in Praia, Cape Verde, in January and February 2008. The aerosol at Praia is a superposition of mineral dust, sea-salt, sulphates and soot. Particles smaller than 500 nm are mainly mineral dust, mineral dust-sulphate mixtures, sulphates and soot-sulphate mixtures. Particles larger then 2.5 μm consist of mineral dust, sea-salt and few mineral dust-sulphate mixtures. A transition range exists in between. The major internal mixtures are mineral dust-sulphate and soot-sulphate. Mineral dust-sea-salt mixtures occur occasionally, mineral dust-soot mixtures were not observed. The aspect ratio was 1.3-1.4 for dry particles smaller than 500 nm and 1.6-1.7 for larger ones. Parameterizations are given for dry and humid state. Although the real part of the refractive index showed low variation (1.55-1.58 at 532 nm), a multi-modal imaginary part was detected as function of particle size, reflecting the complex composition. Soot mainly influences the absorption for wavelengths longer than the haematite absorption edge, whereas for shorter wavelengths dust is dominating. The refractive index of the aerosol depends on the source region of the mineral dust and on the presence/absence of a marine component.

  19. Electron microscopy of particles collected at Praia, Cape Verde, during the Saharan Mineral Dust Experiment: particle chemistry, shape, mixing state and complex refractive index

    Energy Technology Data Exchange (ETDEWEB)

    Kandler, K.; Lieke, K.; Benker, N. (Institut fur Angewandte Geowissenschaften, Technische Universitaet Darmstadt, Darmstadt (Germany)), e-mail: kzk@gmx.de (and others)

    2011-09-15

    A large field experiment of the Saharan Mineral Dust Experiment (SAMUM) was performed in Praia, Cape Verde, in January and February 2008. The aerosol at Praia is a superposition of mineral dust, sea-salt, sulphates and soot. Particles smaller than 500 nm are mainly mineral dust, mineral dust-sulphate mixtures, sulphates and soot-sulphate mixtures. Particles larger then 2.5mum consist of mineral dust, sea-salt and few mineral dust-sulphate mixtures. A transition range exists in between. The major internal mixtures are mineral dust-sulphate and soot-sulphate. Mineral dust-sea-salt mixtures occur occasionally, mineral dust-soot mixtures were not observed. The aspect ratio was 1.3-1.4 for dry particles smaller than 500 nm and 1.6-1.7 for larger ones. Parameterizations are given for dry and humid state. Although the real part of the refractive index showed low variation (1.55-1.58 at 532 nm), a multi-modal imaginary part was detected as function of particle size, reflecting the complex composition. Soot mainly influences the absorption for wavelengths longer than the haematite absorption edge, whereas for shorter wavelengths dust is dominating. The refractive index of the aerosol depends on the source region of the mineral dust and on the presence/absence of a marine component

  20. Cometary Dust

    Science.gov (United States)

    Levasseur-Regourd, Anny-Chantal; Agarwal, Jessica; Cottin, Hervé; Engrand, Cécile; Flynn, George; Fulle, Marco; Gombosi, Tamas; Langevin, Yves; Lasue, Jérémie; Mannel, Thurid; Merouane, Sihane; Poch, Olivier; Thomas, Nicolas; Westphal, Andrew

    2018-04-01

    This review presents our understanding of cometary dust at the end of 2017. For decades, insight about the dust ejected by nuclei of comets had stemmed from remote observations from Earth or Earth's orbit, and from flybys, including the samples of dust returned to Earth for laboratory studies by the Stardust return capsule. The long-duration Rosetta mission has recently provided a huge and unique amount of data, obtained using numerous instruments, including innovative dust instruments, over a wide range of distances from the Sun and from the nucleus. The diverse approaches available to study dust in comets, together with the related theoretical and experimental studies, provide evidence of the composition and physical properties of dust particles, e.g., the presence of a large fraction of carbon in macromolecules, and of aggregates on a wide range of scales. The results have opened vivid discussions on the variety of dust-release processes and on the diversity of dust properties in comets, as well as on the formation of cometary dust, and on its presence in the near-Earth interplanetary medium. These discussions stress the significance of future explorations as a way to decipher the formation and evolution of our Solar System.

  1. Stable carbon and nitrogen isotopic compositions of ambient aerosols collected from Okinawa Island in the western North Pacific Rim, an outflow region of Asian dusts and pollutants

    Science.gov (United States)

    Kunwar, Bhagawati; Kawamura, Kimitaka; Zhu, Chunmao

    2016-04-01

    Stable carbon (δ13C) and nitrogen (δ15N) isotope ratios were measured for total carbon (TC) and nitrogen (TN), respectively, in aerosol (TSP) samples collected at Cape Hedo, Okinawa, an outflow region of Asian pollutants, during 2009-2010. The averaged δ13C and δ15N ratios are -22.2‰ and +12.5‰, respectively. The δ13C values are similar in both spring (-22.5‰) and winter (-22.5‰), suggesting the similar sources and/or source regions. We found that δ13C from Okinawa aerosols are ca. 2‰ higher than those reported from Chinese megacities probably due to photochemical aging of organic aerosols. A strong correlation (r = 0.81) was found between nss-Ca and TSP, suggesting that springtime aerosols are influenced from Asian dusts. However, carbonates in the Asian dusts were titrated with acidic species such as sulfuric acid and oxalic acid during atmospheric transport although two samples suggested the presence of remaining carbonate. No correlations were found between δ13C and tracer compounds (levoglucosan, elemental carbon, oxalic acid, and Na+). During winter and spring, coal burning is significant source in China. Based on isotopic mass balance, contribution of coal burning origin particles to total aerosol carbon was estimated as ca. 97% in winter, which is probably associated with the high emissions in China. Contribution of NO3- to TN was on average 45% whereas that of NH4+ was 18%. These results suggest that vehicular exhaust is an important source of TN in Okinawa aerosols. Concentration of water-soluble organic nitrogen (WSON) is higher in summer, suggesting that WSON is more emitted from the ocean in warmer season whereas inorganic nitrogen is more emitted in winter and spring from pollution sources in the Asian continent.

  2. Electrostatic collection efficiency in binary fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    Romero, A.; Guardiola, J.; Rincon, J. (Univ. of Alcala de Henares, Madrid (Spain))

    1992-01-01

    Fluidized beds of binary mixtures have been used to clean air streams containing dust particles in the size range 4.4 to 14 {mu}m. All beds were composed of glass beads and plastic granules mixed at different proportions. The effect on the electrostatic collection efficiency of a number of variables, including type of collecting mixture, bed height, and gas velocity, was examined. To calculate the single collection efficiency from experimental results, an early model proposed by Clift et al. was used. The electrostatic collection efficiency was determined by subtracting the other individual mechanism efficiencies from the single particle collection efficiency.

  3. Industrial robot having dust-proof structure

    Energy Technology Data Exchange (ETDEWEB)

    Torii, N.; Ito, S.; Wakio, H.; Iwasaki, K

    1989-06-06

    This patent describes an industrial robot having a dust-proof structure comprising: at least one dust cover having an opening; a linearly moving unit extending through the opening of the dust cover and moved back and forth in the longitudinal direction thereof; a suction unit for exerting suction on an interior of the dust cover to cause an air stream to flow from outside the dust cover into the dust cover through the opening; and a ring member disposed at the opening of the dust cover in such a manner as to encompass the outer periphery of the linearly moving unit through a gap, the ring member being formed at the inner peripheral surface thereof with at least one annular groove for reserving air, encompassing the outer periphery of the linearly moving unit.

  4. Final Reports of the Stardust ISPE: Seven Probable Interstellar Dust Particles

    Science.gov (United States)

    Allen, Carlton; Sans Tresseras, Juan-Angel; Westphal, Andrew J.; Stroud, Rhonda M.; Bechtel, Hans A.; Brenker, Frank E.; Butterworth, Anna L.; Flynn, George J.; Frank, David R.; Gainsforth, Zack; hide

    2014-01-01

    The Stardust spacecraft carried the first spaceborne collector specifically designed to capture and return a sample of contemporary interstellar dust to terrestrial laboratories for analysis [1]. The collector was exposed to the interstellar dust stream in two periods in 2000 and 2002 with a total exposure of approximately 1.8 10(exp 6) square meters sec. Approximately 85% of the collector consisted of aerogel, and the remainder consisted of Al foils. The Stardust Interstellar Preliminary Examination (ISPE) was a consortiumbased effort to characterize the collection in sufficient detail to enable future investigators to make informed sample requests. Among the questions to be answered were these: How many impacts are consistent in their characteristics with interstellar dust, with interplanetary dust, and with secondary ejecta from impacts on the spacecraft? Are the materials amorphous or crystalline? Are organics detectable? An additional goal of the ISPE was to develop or refine the techniques for preparation, analysis, and curation of these tiny samples, expected to be approximately 1 picogram or smaller, roughly three orders of magnitude smaller in mass than the samples in other small particle collections in NASA's collections - the cometary samples returned by Stardust, and the collection of Interplanetary Dust Particles collected in the stratosphere.

  5. Dust characterization in FTU tokamak

    Science.gov (United States)

    De Angeli, M.; Maddaluno, G.; Laguardia, L.; Ripamonti, D.; Perelli Cippo, E.; Apicella, M. L.; Conti, C.; Giacomi, G.; Grosso, G.

    2015-08-01

    Dust present in the vessel of FTU has been collected and analysed. Being FTU a device with full metal plasma facing components for the whole life and equipped with a liquid lithium limiter (LLL) make FTU of special interest from a point of view of dust studies. Analyses were conducted by standard dust analysis methods and by dedicated analysis, as X-rays and neutron diffraction, to investigate the presence of lithium compounds due the presence of the LLL in FTU. Dust collected near the LLL presents a different elemental composition, namely Li compounds, compared to the dust collected in the rest of the vessel; in particular LiO2, LiOH, and Li2CO3. On the basis of these results, the formation of Li2CO3 is proposed via a two steps process. Results of fuel retention measured by thermal desorption spectroscopy (TDS) method show that fuel retention should not be an issue for FTU.

  6. Parameterizing the interstellar dust temperature

    Science.gov (United States)

    Hocuk, S.; Szűcs, L.; Caselli, P.; Cazaux, S.; Spaans, M.; Esplugues, G. B.

    2017-08-01

    The temperature of interstellar dust particles is of great importance to astronomers. It plays a crucial role in the thermodynamics of interstellar clouds, because of the gas-dust collisional coupling. It is also a key parameter in astrochemical studies that governs the rate at which molecules form on dust. In 3D (magneto)hydrodynamic simulations often a simple expression for the dust temperature is adopted, because of computational constraints, while astrochemical modelers tend to keep the dust temperature constant over a large range of parameter space. Our aim is to provide an easy-to-use parametric expression for the dust temperature as a function of visual extinction (AV) and to shed light on the critical dependencies of the dust temperature on the grain composition. We obtain an expression for the dust temperature by semi-analytically solving the dust thermal balance for different types of grains and compare to a collection of recent observational measurements. We also explore the effect of ices on the dust temperature. Our results show that a mixed carbonaceous-silicate type dust with a high carbon volume fraction matches the observations best. We find that ice formation allows the dust to be warmer by up to 15% at high optical depths (AV> 20 mag) in the interstellar medium. Our parametric expression for the dust temperature is presented as Td = [ 11 + 5.7 × tanh(0.61 - log 10(AV) ]χuv1/5.9, where χuv is in units of the Draine (1978, ApJS, 36, 595) UV field.

  7. Streams with Strahler Stream Order

    Data.gov (United States)

    Minnesota Department of Natural Resources — Stream segments with Strahler stream order values assigned. As of 01/08/08 the linework is from the DNR24K stream coverages and will not match the updated...

  8. Health hazards of cement dust

    International Nuclear Information System (INIS)

    Meo, Sultan A.

    2004-01-01

    ven in the 21st century, millions of people are working daily in a dusty environment. They are exposed to different types of health hazards such as fume, gases and dust, which are risk factors in developing occupational disease. Cement industry is involved in the development of structure of this advanced and modern world but generates dust during its production. Cement dust causes lung function impairment, chronic obstructive lung disease, restrictive lung disease, pneumoconiosis and carcinoma of the lungs, stomach and colon. Other studies have shown that cement dust may enter into the systemic circulation and thereby reach the essentially all the organs of body and affects the different tissues including heart, liver, spleen, bone, muscles and hairs and ultimately affecting their micro-structure and physiological performance. Most of the studies have been previously attempted to evaluate the effects of cement dust exposure on the basis of spirometry or radiology, or both. However, collective effort describing the general effects of cement dust on different organ and systems in humans or animals, or both has not been published. Therefore, the aim of this review is to gather the potential toxic effects of cement dust and to minimize the health risks in cement mill workers by providing them with information regarding the hazards of cement dust. (author)

  9. The effects of Dual-Stream commingled collection of recyclables from households in Sønderborg, Denmark

    DEFF Research Database (Denmark)

    Cimpan, Ciprian; Wenzel, Henrik

    2013-01-01

    in residual waste, which is used for energy production in the local waste CHP plant, is being compensated by import of industrial waste from northern Germany. The results of this study credit the new management system with an increase of 8-26% in primary energy and 5-33% in GHG emissions savings over the old...... of the previous and current waste management systems in the municipality in terms of primary energy and greenhouse gas emission savings. In the new systems approx. 65% more materials are collected for recycling (an increase from 18% to 30% in the share of domestic household waste). The corresponding decrease...... management system, depending on the exclusion/inclusion of implications related to imported waste amounts in the system analysis....

  10. Inflammatory potential in relation to the microbial content of settled dust samples collected from moisture domaged and reference schools: results of HITEA study.

    NARCIS (Netherlands)

    Huttunen, K.; Tirkkonen, J.; Täubel, M.; Krop, E.; Mikkonen, S.; Pekkanen, J.; Heederik, D.; Zock, J.P.; Hyvärinen, A.; Hirvonen, M.R.

    2016-01-01

    Aiming to identify factors causing the adverse health effects associated with moisture-damaged indoor environments, we analyzed immunotoxicological potential of settled dust from moisture-damaged and reference schools in relation to their microbiological composition. Mouse RAW264.7 macrophages were

  11. Inflammatory potential in relation to the microbial content of settled dust samples collected from moisture damaged and reference schools : Results of HITEA study

    NARCIS (Netherlands)

    Huttunen, Kati; Tirkkonen, Jenni; Täubel, Martin; Krop, Esmeralda; Mikkonen, Santtu; Pekkanen, Juha; Heederik, Dick; Zock, Jan-Paul; Hyvärinen, Anne; Hirvonen, Maija-Riitta

    Aiming to identify factors causing the adverse health effects associated with moisture damaged indoor environments, we analyzed immunotoxicological potential of settled dust from moisture damaged and reference schools in relation to their microbiological composition. Mouse RAW264.7 macrophages were

  12. Identification, characteristics and human exposure assessments of triclosan, bisphenol-A, and four commonly used organic UV filters in indoor dust collected from Shanghai, China.

    Science.gov (United States)

    Ao, Junjie; Yuan, Tao; Ma, Yuning; Gao, Li; Ni, Ni; Li, Dan

    2017-10-01

    Indoor dust is a very significant medium to understand human exposure of emerging contaminants. A novel and robust analytical method to measure the amounts of six personal care products (PCPs) (triclosan, bisphenol-A and four commonly used organic ultraviolet (UV) filters) simultaneously in indoor dust is developed in this paper. Target analytes were extracted using accelerated solvent extraction. After sample cleanup by solid-phase extraction (SPE), the extracts were derivatized and analyzed using gas chromatography-tandem mass spectrometry. The method detection limits achieves 0.16-0.62 pg g -1 (except for 4-methylbenzylidene camphor with 3800 pg g -1 ). The method was successfully applied to the analysis of 110 indoor dust samples from Shanghai, China. Results showed that the PCPs were found in most of the samples analyzed. The concentrations of the most analytes are relatively lower than those reported in USA, Japan, and European countries. The median concentration of octocrylene (OC) (1170.4 ng g -1 ) was found to be nearly 5-10 times higher than those of other analytes. The significantly higher concentration of ∑PCPs was observed in indoor dusts from residences than from offices (P UV filters in China. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Where the rubber meets the road: long-term in-stream data collection to inform regional land management monitoring in the Pacific Northwest

    Science.gov (United States)

    Hirsch, C.

    2017-12-01

    The initiation of the Northwest Forest Plan (NWFP) in 1994 brought a sea change to federal land management agencies of the Pacific Northwest. The NWFP was developed in response to the listing of the Northern Spotted Owl and concern about declining populations of Pacific Salmon. The Aquatic and Riparian Effectiveness Monitoring Program (AREMP) was developed to track changes that occurred as a result of active and passive management on the landscape. A significant management change affecting riparian areas was the creation of buffers around fish bearing and non-fish bearing streams. Two monitoring arms of the AREMP program focus on upslope and in-stream conditions in order to capture watershed-scale effects of land management changes. Field data to support the in-stream monitoring mission of AREMP began in 2002 with a study design based on an 8-year re-survey rotation. The sampling design was intended to capture watershed-scale variability across the broad and diverse study area in western Washington, western Oregon, and northwest California. 2017 marks repeat visits of every site and opens the door to more detailed assessments of changes that have occurred at local and regional extents over this time period. Results so far show improving trends in characteristics such as water temperature and macroinvertebrate community diversity. Maintaining an ongoing and relevant monitoring program over time has required a strong commitment to quality control in terms of data collection and analysis, and an openness to how AREMP can provide management relevant information as new challenges occur. AREMP's mandated role as the aquatic monitoring arm of the NWFP provides the overarching framework within which the program operates. However, new emerging topics of relevance to aquatic managers such as climate change and aquatic invasive species have been rolled into the mission over time. By being responsive to new challenges, and providing consistent feedback, AREMP has been able to

  14. Dust Dynamics Near Planetary Surfaces

    Science.gov (United States)

    Colwell, Joshua; Hughes, Anna; Grund, Chris

    streams observed by Apollo astronauts and potentially also by the Clementine spacecraft. In addition to the Surveyor images of lunar horizon glow and the high altitude streamer measurements, the Apollo 17 Lunar Ejecta and Meteorite surface package detected signals consistent with the impact of relatively slow-moving dust particles that may have been charged dust electrostatically levitated from the surface. There is renewed interest in this near-surface dust environment with plans to return robotic landers and astronauts to the lunar surface. No Apollo-era instruments were specifically designed to detect or measure dust levitated off the lunar surface. One new experiment under study is the Autonomous Lunar Dust Observer (ALDO). ALDO is a high-sensitivity scanning lidar (laser radar) that autonomously maps and records its 3-D dust environment. Flexibility of programmable scan pattern enables ALDO to characterize the dust context in and around experiment sites. Repeated shallow angle scans in a vertical plane enable high vertical resolution studies of dust levitation near the ground. Single elevation angle sector or full azimuth scans enable large-area statistical surveys of the frequency and size of ejecta plumes from micrometeoroid impacts, and vertical or fixed-angle stares enable very high sensitivity dust profiles to extended ranges. It is estimated that backscatter from dust concentrations as low as 1/cm3 can be measured. The concept is equally applicable to surface and atmospheric studies of other airless bodies.

  15. [Determination of house dust mites in Eskisehir].

    Science.gov (United States)

    Doğan, Nihal; Aycan, Ozlem Makbule; Miman, Ozlem; Atambay, Metin; Daldal, Nilgün

    2008-01-01

    House dust contains various organic and inorganic materials. The most important parts of the house dust are dust mites causing allergic diseases such as allergic rhinitis, asthma, atopic dermatitis and seasonal keratoconjunctivitis. In this study, a total of 72 random house dust samples collected from various regions of Eskisehir were examined. The dust samples were examined by the lactic acid precipitation method which was modified from the Spieksma-Boezaman's method. The mite positive house dust rate was 16.67% including Dermatophagoides pteronyssinus, Chortoglyphus arcuatus and Tyrophagus sp. It was concluded that investigation of a greater number of samples would lead to more precise rate of detection of mite positive dust and also that more mite species would be found.

  16. Long-term EARLINET dust observations

    Science.gov (United States)

    Mona, Lucia; Amiridis, Vassilis; Amodeo, Aldo; Binietoglou, Ioannis; D'Amico, Giuseppe; Schwarz, Anja; Papagiannopoulos, Nikolaos; Papayannis, Alexandros; Sicard, Michael; Comeron, Adolfo; Pappalardo, Gelsomina

    2015-04-01

    Systematic observations of Saharan dust events over Europe are performed from May 2000 by EARLINET, the European Aerosol Research LIdar NETwork. EARLINET is a coordinated network of stations that make use of advanced lidar methods for the vertical profiling of aerosols. The backbone of EARLINET network is a common schedule for performing the measurements and the quality assurance of instruments/data. Particular attention is paid to monitoring the Saharan dust intrusions over the European continent. The geographical distribution of the EARLINET stations is particularly appealing for the dust observation, with stations located all around the Mediterranean and in the center of the Mediterranean (Italian stations) where dust intrusions are frequent, and with several stations in the central Europe where dust penetrates occasionally. All aerosol backscatter and extinction profiles related to observations collected during these alerts are grouped in the devoted "Saharan dust" category of the EARLINET database. This category consists of about 4700 files (as of December 2013). Case studies involving several stations around Europe selected from this long-term database have been provided the opportunity to investigate dust modification processes during transport over the continent. More important, the long term EARLINET dust monitoring allows the investigation of the horizontal and vertical extent of dust outbreaks over Europe and the climatological analysis of dust optical intensive and extensive properties at continental scale. This long-term database is also a unique tool for a systematic comparison with dust model outputs and satellite-derived dust products. Because of the relevance for both dust modeling and satellite retrievals improvement, results about desert dust layers extensive properties as a function of season and source regions are investigated and will be presented at the conference. First comparisons with models outputs and CALIPSO dust products will be

  17. Novel advanced methods of clearing air from fine dust

    OpenAIRE

    Batluk, V.; Proskurina, I.; Nadorshyn, Ye; Sheluh, Yu

    2007-01-01

    A completely new design of centrifugal inertial dust collector is proposed here its research allow to affirm that the efficiency of dust collecting increases for 10-12 % and powerand steel intensity decreases.

  18. Pulling History from the Waste Stream: Identification and Collection of Manhattan Project and Cold War Era Artifacts on the Hanford Site

    Energy Technology Data Exchange (ETDEWEB)

    Marceau, Thomas E.; Watson, Thomas L.

    2013-11-13

    One man's trash is another man's treasure. Not everything called "waste" is meant for the refuse pile. The mission of the Curation Program is at direct odds with the remediation objectives of the Hanford Site. While others are busily tearing down and burying the Site's physical structures and their associated contents, the Curation Program seeks to preserve the tangible elements of the Site's history from these structures for future generations before they flow into the waste stream. Under the provisions of a Programmatic Agreement, Cultural Resources staff initiated a project to identify and collect artifacts and archives that have historic or interpretive value in documenting the role of the Hanford Site throughout the Manhattan Project and Cold War Era. The genesis of Hanford's modern day Curation Program, its evolution over nearly two decades, issues encountered, and lessons learned along the way -- particularly the importance of upper management advocacy, when and how identification efforts should be accomplished, the challenges of working within a radiological setting, and the importance of first hand information -- are presented.

  19. Assessment of trace element levels in muscle tissues of fish species collected from a river, stream, lake, and sea in Sakarya, Turkey.

    Science.gov (United States)

    Küpeli, Tülay; Altundağ, Hüseyin; Imamoğlu, Mustafa

    2014-01-01

    Levels of some trace and essential elements, including Al, B, Ba, Cr, Cu, Fe, Mn, Ni, Sr, and Zn, were determined in 17 different fish species from Sakarya River, Çark Stream, Sapanca Lake, and Western Black Sea using ICP-OES after microwave (MW) digestion procedure. During preparation of samples for analysis, wet and MW digestion methods were also compared. Accuracy of the digestion methods was checked by the analysis of DORM-3 reference material (Fish Protein Certified Reference Material for Trace Metals). Concentrations of trace elements were found as Al: 6.5-48.5, B: 0.06-3.30, Ba: 0.09-2.92, Cr: 0.02-1.64, Cu: 0.13-2.28, Fe: 7.28-39.9, Mn: 0.08-11.4, Ni: 0.01-26.1, Sr: 0.17-13.5, and Zn: 11.5-52.9 µg g(-1). The obtained results were compared with other studies published in the literature. Trace element levels in various fish species collected from waters in Sakarya region were found to be below limit values provided by Turkish Food Codex (TFC), Food and Agriculture Organization (FAO), and World Health Organization (WHO).

  20. Assessment of Trace Element Levels in Muscle Tissues of Fish Species Collected from a River, Stream, Lake, and Sea in Sakarya, Turkey

    Directory of Open Access Journals (Sweden)

    Tülay Küpeli

    2014-01-01

    Full Text Available Levels of some trace and essential elements, including Al, B, Ba, Cr, Cu, Fe, Mn, Ni, Sr, and Zn, were determined in 17 different fish species from Sakarya River, Çark Stream, Sapanca Lake, and Western Black Sea using ICP-OES after microwave (MW digestion procedure. During preparation of samples for analysis, wet and MW digestion methods were also compared. Accuracy of the digestion methods was checked by the analysis of DORM-3 reference material (Fish Protein Certified Reference Material for Trace Metals. Concentrations of trace elements were found as Al: 6.5–48.5, B: 0.06–3.30, Ba: 0.09–2.92, Cr: 0.02–1.64, Cu: 0.13–2.28, Fe: 7.28–39.9, Mn: 0.08–11.4, Ni: 0.01–26.1, Sr: 0.17–13.5, and Zn: 11.5–52.9 µg g−1. The obtained results were compared with other studies published in the literature. Trace element levels in various fish species collected from waters in Sakarya region were found to be below limit values provided by Turkish Food Codex (TFC, Food and Agriculture Organization (FAO, and World Health Organization (WHO.

  1. Pulling History from the Waste Stream: Identification and Collection of Manhattan Project and Cold War Era Artifacts on the Hanford Site

    International Nuclear Information System (INIS)

    Marceau, Thomas E.; Watson, Thomas L.

    2013-01-01

    One man's trash is another man's treasure. Not everything called 'waste' is meant for the refuse pile. The mission of the Curation Program is at direct odds with the remediation objectives of the Hanford Site. While others are busily tearing down and burying the Site's physical structures and their associated contents, the Curation Program seeks to preserve the tangible elements of the Site's history from these structures for future generations before they flow into the waste stream. Under the provisions of a Programmatic Agreement, Cultural Resources staff initiated a project to identify and collect artifacts and archives that have historic or interpretive value in documenting the role of the Hanford Site throughout the Manhattan Project and Cold War Era. The genesis of Hanford's modern day Curation Program, its evolution over nearly two decades, issues encountered, and lessons learned along the way -- particularly the importance of upper management advocacy, when and how identification efforts should be accomplished, the challenges of working within a radiological setting, and the importance of first hand information -- are presented

  2. Contribution of pharmaceuticals and personal care products (PPCPs) to whole toxicity of water samples collected in effluent-dominated urban streams.

    Science.gov (United States)

    Tamura, Ikumi; Yasuda, Yusuke; Kagota, Kei-Ichiro; Yoneda, Saori; Nakada, Norihide; Kumar, Vimal; Kameda, Yutaka; Kimura, Kumiko; Tatarazako, Norihisa; Yamamoto, Hiroshi

    2017-10-01

    Water samples were collected from effluent-dominated urban streams in Tokushima, Kyoto, and Saitama in Japan to roughly determine the contribution of pharmaceuticals and personal care products (PPCPs) and surfactants to whole toxicity of the water. Approximately 100 PPCPs including anionic surfactants such as linear alkylbenzene sulfonate (LAS), were chemically analyzed. Using 14 water samples, chronic or sub-chronic toxicity tests were conducted on three aquatic species, the green alga Raphidocelis subcapitata, the cladoceran Ceriodaphnia dubia, and the zebrafish Danio rerio. Bioassays for the selected individual PPCPs were conducted using the three species. Assuming the concentration addition (CA) model, the contribution of each PPCP to the whole toxicity of the riverwater was estimated based on toxicity unit (TU). The contribution of PPCPs, which primarily consists of a few antibiotic agents such as triclosan and clarithromycin, ranged from 0.9% to 69% of the whole toxicity of the water samples for algae, whereas the selected LAS congeners accounted for at most 5.3%. In contrast, the contribution of LAS ranged from 0.067% to 86% and from 0.021% to 27% of the whole toxicity for cladoceran and zebrafish, respectively, whereas that of PPCPs for these species was at most 2.1% at all sampling points. Our results suggest a limited contribution of PPCPs except for antimicrobial agents and the possible substantial contribution of LAS to toxicity in cladocerans and zebrafish. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Trace metals in urban road dust

    International Nuclear Information System (INIS)

    Randazzo, Loredana Antonella; Dongarra, Gaetano; Manno, Emanuela; Varrica, Daniela

    2006-01-01

    Heavy metals associated with urban road dust is a matter for concern as they may have serious effects on biological systems. The bioavailability and potential toxicity of metals bound to urban dust is related to the specific chemical form of the element. In the present article are reported the determinations and chemical speciation of As, Ba, Cr, Cu, Mo, Ni, Pb and Zn in six samples of road dust collected within the urban centre and the outskirts of Palermo [it

  4. Respirable quartz hazard associated with coal mine roof bolter dust

    International Nuclear Information System (INIS)

    Joy, G.J.; Beck, T.W.; Listak, J.M.

    2010-01-01

    Pneumoconiosis has been reported to be increasing among underground coal miners in the Southern Appalachian Region. The National Institute for Occupational Safety and Health conducted a study to examine the particle size distribution and quartz content of dust generated by the installation of roof bolts in mines. Forty-six bulk samples of roof bolting machine pre-cleaner cyclone dump dust and collector box dust were collected from 26 underground coal mines. Real-time and integrated airborne respirable dust concentrations were measured on 3 mining sections in 2 mines. The real-time airborne dust concentrations profiles were examined to identify any concentration changes that might be associated with pre-cleaner cyclone dust discharge events. The study showed that bolter dust is a potential inhalation hazard due to the fraction of dust less than 10 μm in size, and the quartz content of the dust. The pre-cleaner cyclone dust was significantly larger than the collector box dust, indicating that the pre-cleaner functioned properly in removing the larger dust size fraction from the airstream. However, the pre-cleaner dust still contained a substantial amount of respirable dust. It was concluded that in order to maintain the effectiveness of a roof bolter dust collector, periodic removal of dust is required. Appropriate work procedures and equipment are necessary to minimize exposure during this cleaning task. 13 refs., 3 tabs., 2 figs.

  5. Interstellar dust in and around the heliosphere

    Science.gov (United States)

    Mann, I.; Czechowski, A.

    The motion of the sun relative to the local interstellar medium causes a stream of interstellar medium dust toward the heliosphere. Small dust particles gain a high charge to mass ratio and are deflected from their original flow direction with the interstellar gas. The majority of interstellar dust particles of sizes below 0.1 micrometer are deflected from entering the heliosphere. A pile-up of interstellar dust similar to that of the hydrogen wall appears around the heliosphere, but is restricted to small grains. We use a simple model of the heliospheric transition region to calculate the velocity distributions of these interstellar grains in the neighborhood of the heliosphere. Different assumptions about the interstellar magnetic field and the structure of the plasma flow are considered. We find that the distributions are sensitive to the structure of the heliospheric transition region, in particular to the presence of a sharp bow shock. Larger interstellar dust particles enter the heliosphere where several deflection mechanisms selectively act on dust particles of certain sizes and properties. When considering the dynamics of small grains that have entered the heliosphere the effects of the heliospheric current sheet (downstream and upstream from the termination shock) and the solar cycle can facilitate the entry of charged grains into the inner solar system, although the unipolar field regions approaching the ecliptic act as an obstacle to it. The dust fluxes in the inner heliosphere also depend on the influence of radiation pressure and solar gravity. The influence of these forces can be seen in the mass distributions of interstellar dust measured in-situ from spacecraft at different locations. The conditions of dust dynamics depend on the initial velocity distribution of grains in the interstellar medium. Small dust particles are coupled to the gas of the interstellar medium while larger dust particles may not be coupled to the local interstellar cloud and

  6. X-ray photoevaporation's limited success in the formation of planetesimals by the streaming instability

    Science.gov (United States)

    Ercolano, Barbara; Jennings, Jeff; Rosotti, Giovanni; Birnstiel, Tilman

    2017-12-01

    The streaming instability is often invoked as solution to the fragmentation and drift barriers in planetesimal formation, catalysing the aggregation of dust on kyr time-scales to grow km-sized cores. However, there remains a lack of consensus on the physical mechanism(s) responsible for initiating it. One potential avenue is disc photoevaporation, wherein the preferential removal of relatively dust-free gas increases the disc metallicity. Late in the disc lifetime, photoevaporation dominates viscous accretion, creating a gradient in the depleted gas surface density near the location of the gap. This induces a local pressure maximum that collects drifting dust particles, which may then become susceptible to the streaming instability. Using a one-dimensional viscous evolution model of a disc subject to internal X-ray photoevaporation, we explore the efficacy of this process to build planetesimals. Over a range of parameters, we find that the amount of dust mass converted into planetesimals is often investigation that considered an far-ultra-violet (FUV)-driven photoevaporation model and reported the formation of tens of M⊕ at large (>100 au) disc radii. The discrepancies are primarily a consequence of the different photoevaporation profiles assumed. Until observations more tightly constrain photoevaporation models, the relevance of this process to the formation of planets remains uncertain.

  7. Identifying sources of aeolian mineral dust: Present and past

    Science.gov (United States)

    Muhs, Daniel R; Prospero, Joseph M; Baddock, Matthew C; Gill, Thomas E

    2014-01-01

    Aeolian mineral dust is an important component of the Earth’s environmental systems, playing roles in the planetary radiation balance, as a source of fertilizer for biota in both terrestrial and marine realms and as an archive for understanding atmospheric circulation and paleoclimate in the geologic past. Crucial to understanding all of these roles of dust is the identification of dust sources. Here we review the methods used to identify dust sources active at present and in the past. Contemporary dust sources, produced by both glaciogenic and non-glaciogenic processes, can be readily identified by the use of Earth-orbiting satellites. These data show that present dust sources are concentrated in a global dust belt that encompasses large topographic basins in low-latitude arid and semiarid regions. Geomorphic studies indicate that specific point sources for dust in this zone include dry or ephemeral lakes, intermittent stream courses, dune fields, and some bedrock surfaces. Back-trajectory analyses are also used to identify dust sources, through modeling of wind fields and the movement of air parcels over periods of several days. Identification of dust sources from the past requires novel approaches that are part of the geologic toolbox of provenance studies. Identification of most dust sources of the past requires the use of physical, mineralogical, geochemical, and isotopic analyses of dust deposits. Physical properties include systematic spatial changes in dust deposit thickness and particle size away from a source. Mineralogy and geochemistry can pinpoint dust sources by clay mineral ratios and Sc-Th-La abundances, respectively. The most commonly used isotopic methods utilize isotopes of Nd, Sr, and Pb and have been applied extensively in dust archives of deep-sea cores, ice cores, and loess. All these methods have shown that dust sources have changed over time, with far more abundant dust supplies existing during glacial periods. Greater dust supplies in

  8. Electrostatic Dust Control on Planetary Surfaces

    Science.gov (United States)

    Clark, P. E.; Calle, C. I.; Curtis, S. A.; Keller, J. F.; Minetto, F.; Mantovani, J. G.

    2007-01-01

    Successful operation for exploration of planetary regoliths will depend on the capability to keep surfaces free of dust which could compromise performance and to collect dust for characterization. Such study is essential in order to resolve issues in dealing with regolith fines identified during the Apollo missions where dust behaved like abrasive Velcro before returning to the Moon. During Moon landings, locally-induced stirring of the regolith caused dust to be suspended long enough to come into contact with conducting surfaces. Lunar fines, because of their electrostatic charging, were difficult to collect and sparsely sampled: bag seals were broken, samples contaminated and lost. Our objectives here are to describe a multi-faceted electrostatically-based approach and methodology for addressing this issue, as well as to present our preliminary results which confirm the view that the successful strategy will deal with dust dynamics resulting from interaction between mechanical and electrostatic forces. Our device concept combines electron or ion beams, acting as a plasma dust sweeper to control the flow of dust by systematic scanning of the surface with an electrostatically controlled potential. A plate of the opposite potential used to induce dust migration in the presence of an electrical field. Our goal is a compact device of dust for sampling as part of the extended exploration process on extensive areas of exposed impact-generated regolith, on Mercury, Mars, asteroids or outer solar system satellites, as well as the Moon.

  9. Stream systems.

    Science.gov (United States)

    Jack E. Williams; Gordon H. Reeves

    2006-01-01

    Restored, high-quality streams provide innumerable benefits to society. In the Pacific Northwest, high-quality stream habitat often is associated with an abundance of salmonid fishes such as chinook salmon (Oncorhynchus tshawytscha), coho salmon (O. kisutch), and steelhead (O. mykiss). Many other native...

  10. Stream Evaluation

    Data.gov (United States)

    Kansas Data Access and Support Center — Digital representation of the map accompanying the "Kansas stream and river fishery resource evaluation" (R.E. Moss and K. Brunson, 1981.U.S. Fish and Wildlife...

  11. House dust in seven Danish offices

    Science.gov (United States)

    Mølhave, L.; Schneider, T.; Kjærgaard, S. K.; Larsen, L.; Norn, S.; Jørgensen, O.

    Floor dust from Danish offices was collected and analyzed. The dust was to be used in an exposure experiment. The dust was analyzed to show the composition of the dust which can be a source of airborne dust indoors. About 11 kg of dust from vacuum cleaner bags from seven Danish office buildings with about 1047 occupants (12 751 m 2) was processed according to a standardized procedure yielding 5.5 kg of processed bulk dust. The bulk dust contained 130.000-160.000 CFU g -1 microorganisms and 71.000-90.000 CFU g -1 microfungi. The content of culturable microfungi was 65-123 CFU 30 g -1 dust. The content of endotoxins ranged from 5.06-7.24 EU g -1 (1.45 ng g -1 to 1.01 ng g -1). Allergens (ng g -1) were from 147-159 (Mite), 395-746 (dog) and 103-330 (cat). The macro molecular organic compounds (the MOD-content) varied from 7.8-9.8 mg g -1. The threshold of release of histamine from basophil leukocytes provoked by the bulk dust was between 0.3 and 1.0 mg ml -1. The water content was 2% (WGT) and the organic fraction 33%. 6.5-5.9% (dry) was water soluble. The fiber content was less than 0.2-1.5% (WGT) and the desorbable VOCs was 176-319 μg g -1. Most of the VOC were aldehydes. However, softeners for plastic (DBP and DEHP) were present. The chemical composition includes human and animal skin fragments, paper fibers, glass wool, wood and textilefibers and inorganic and metal particles. The sizes ranged from 0.001-1 mm and the average specific density was 1.0 g m -3. The bulk dust was resuspended and injected into an exposure chamber. The airborne dust was sampled and analyzed to illustrate the exposures that can result from sedimented dirt and dust. The airborne dust resulting from the bulk dust reached concentrations ranging from 0.26-0.75 mg m -3 in average contained 300-170 CFU m -3. The organic fraction was from 55-70% and the water content about 2.5% (WGT). The content of the dust was compared to the similar results reported in the literature and its toxic potency is

  12. Streaming instability in a velocity–sheared dusty plasma | Duwa ...

    African Journals Online (AJOL)

    A two-stream instability, obtained from kinetic theory, of strongly velocity-sheared inhomogeneous streaming electron in a magnetized plasma in the presence of negatively charged dust is discussed. Various cold plasma approximations were considered and it is shown that when the diamagnetic effect of ion can be ignored ...

  13. Spring Dust Storm Smothers Beijing

    Science.gov (United States)

    2002-01-01

    A few days earlier than usual, a large, dense plume of dust blew southward and eastward from the desert plains of Mongolia-quite smothering to the residents of Beijing. Citizens of northeastern China call this annual event the 'shachenbao,' or 'dust cloud tempest.' However, the tempest normally occurs during the spring time. The dust storm hit Beijing on Friday night, March 15, and began coating everything with a fine, pale brown layer of grit. The region is quite dry; a problem some believe has been exacerbated by decades of deforestation. According to Chinese government estimates, roughly 1 million tons of desert dust and sand blow into Beijing each year. This true-color image was made using two adjacent swaths (click to see the full image) of data from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS), flying aboard the OrbView-2 satellite, on March 17, 2002. The massive dust storm (brownish pixels) can easily be distinguished from clouds (bright white pixels) as it blows across northern Japan and eastward toward the open Pacific Ocean. The black regions are gaps between SeaWiFS' viewing swaths and represent areas where no data were collected. Image courtesy the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  14. Electrode geometry effects on the collection efficiency of submicron and ultra-fine dust particles in spike-plate electrostatic precipitators

    International Nuclear Information System (INIS)

    Brocilo, D; Podlinski, J; Chang, J S; Mizeraczyk, J; Findlay, R D

    2008-01-01

    The collection efficiency of electrostatic precipitators for the submicron particles ranging from 0.1 to 1 μm and ultrafine particles smaller than 0. lμm is below the requirements of new PM2.5 emission regulations. In this work, numerical and experimental studies were conducted to examine the effect of discharge and collecting electrode geometries on the ion density and electric field profiles and consequently their effect on the particle surface charge and collection efficiency. The collection efficiency prediction was based on a modified Deutsche's equation after calculation of three dimensional electric field and ion density profiles. Whereas, the particle surface charge was obtained from diffusion and field charging models. Results show that the collection efficiency of fine particles for the spike-type discharge electrode when compared to the conventional wire-type was improved. Experimental validations were conducted on a bench scale electrostatic precipitator for total and partial collection efficiency of particles ranging in size from 0.01 to 20 μm and the results indicated that the model can be effectively applied for prototype design, modification, and scale-up of collecting and discharge electrodes.

  15. On the wake structure in streaming complex plasmas

    International Nuclear Information System (INIS)

    Ludwig, Patrick; Kählert, Hanno; Bonitz, Michael; Miloch, Wojciech J

    2012-01-01

    The theoretical description of complex (dusty) plasmas requires multiscale concepts that adequately incorporate the correlated interplay of streaming electrons and ions, neutrals and dust grains. Knowing the effective dust-dust interaction, the multiscale problem can be effectively reduced to a one-component plasma model of the dust subsystem. The goal of this paper is a systematic evaluation of the electrostatic potential distribution around a dust grain in the presence of a streaming plasma environment by means of two complementary approaches: (i) a high-precision computation of the dynamically screened Coulomb potential from the dynamic dielectric function and (ii) full 3D particle-in-cell simulations, which self-consistently include dynamical grain charging and nonlinear effects. The range of applicability of these two approaches is addressed. (paper)

  16. Performance of a Venturi scrubber in the removal of fine powder from a confined gas stream

    Directory of Open Access Journals (Sweden)

    Maria Angélica Martins Costa

    2005-06-01

    Full Text Available Experimental results on the performance of a laboratory scale rectangular Venturi scrubber in the removal of fine mineral particles from a confined air stream are presented, and a new correlation is proposed and evaluated. The scrubber was operated with air velocities in the throat varying from 58 m/s to 75 m/s and liquid flow rates varying from 280 ml/min to 900 ml/min. Liquid was injected as a jet emerging from a 1.0 mm orifice at the throat. Results for dust collection grade efficiency varied from 87% to 98% for particles from 0.1 µm to 2.0 µm.

  17. Dusts and Molds

    Science.gov (United States)

    ... limit your exposure by taking these general measures. Think about how they apply in your setting. • Prevent dusts and molds from forming, e.g. drying feeds and cleaning animal areas regularly. • Prevent dusts and molds from becoming ...

  18. LADEE LUNAR DUST EXPERIMENT

    Data.gov (United States)

    National Aeronautics and Space Administration — This archive bundle includes data taken by the Lunar Dust Experiment (LDEX) instrument aboard the Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft....

  19. Construction dust amelioration techniques.

    Science.gov (United States)

    2012-04-01

    Dust produced on seasonal road construction sites in Alaska is both a traffic safety and environmental concern. Dust emanating from : unpaved road surfaces during construction severely reduces visibility and impacts stopping sight distance, and contr...

  20. Physics of interstellar dust

    CERN Document Server

    Krugel, Endrik

    2002-01-01

    The dielectric permeability; How to evaluate grain cross sections; Very small and very big particles; Case studies of Mie calculus; Particle statistics; The radiative transition probability; Structure and composition of dust; Dust radiation; Dust and its environment; Polarization; Grain alignment; PAHs and spectral features of dust; Radiative transport; Diffuse matter in the Milky Way; Stars and their formation; Emission from young stars. Appendices Mathematical formulae; List of symbols.

  1. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from Surface underway observations using Barometric pressure sensor, Carbon dioxide (CO2) gas analyzer and other instruments from Benguela Stream in the Caribbean Sea, English Channel and North Atlantic Ocean from 2015-01-08 to 2015-08-27 (NCEI Accession 0160490)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0160490 includes Surface underway, chemical, meteorological and physical data collected from Benguela Stream in the Caribbean Sea, English Channel and...

  2. Partial pressure (or fugacity) of carbon dioxide, dissolved inorganic carbon, pH, alkalinity, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer and other instruments from Benguela Stream in the Caribbean Sea, English Channel and North Atlantic Ocean from 2012-01-07 to 2012-09-03 (NCEI Accession 0157312)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157312 includes Surface underway, biological, chemical, meteorological, optical and physical data collected from Benguela Stream in the Caribbean...

  3. Partial pressure (or fugacity) of carbon dioxide, dissolved inorganic carbon, pH, alkalinity, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer and other instruments from Benguela Stream in the Caribbean Sea, English Channel and North Atlantic Ocean from 2011-01-08 to 2011-12-29 (NCEI Accession 0157237)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157237 includes Surface underway, biological, chemical, meteorological, optical and physical data collected from Benguela Stream in the Caribbean...

  4. Partial pressure (or fugacity) of carbon dioxide, dissolved inorganic carbon, pH, alkalinity, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer and other instruments from Benguela Stream in the Caribbean Sea, English Channel and North Atlantic Ocean from 2013-09-18 to 2014-01-05 (NCEI Accession 0157352)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157352 includes Surface underway, biological, chemical, meteorological, optical and physical data collected from Benguela Stream in the Caribbean...

  5. Partial pressure (or fugacity) of carbon dioxide, dissolved inorganic carbon, salinity and other variables collected from Surface underway observations using Carbon dioxide (CO2) gas analyzer and other instruments from Benguela Stream in the Caribbean Sea, Davis Strait and others from 2008-03-08 to 2009-01-01 (NCEI Accession 0157314)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0157314 includes Surface underway, chemical, meteorological and physical data collected from Benguela Stream in the Caribbean Sea, Davis Strait,...

  6. House Dust Mites in Erzincan Province.

    Science.gov (United States)

    Zeytun, Erhan; Doğan, Salih; Aykut, Medeni; Özçiçek, Fatih; Ünver, Edhem; Özçiçek, Adalet

    2015-06-01

    We aimed to determine the species of the house dust mites seen in Erzincan, the number of mites per gram of dust in the houses, and the relationship between temperature and the number of mite specimens. For this purpose, 54 dust samples collected from 18 houses located in different districts of Erzincan province between November 2013 and January 2014. These samples were examined by a lactic acid precipitation method. Of the houses in which the dust samples were collected, 94.44% were found to be positive in terms of mites. A total of 844 mite specimens were isolated from the dust samples, and the mean number of mites per gram of dust was found to be 18.34. The most common species was found to be Acarus siro (55.55%) and was followed by Dermatophagoides pteronyssinus (50.00%), Tyrophagus putrescentiae (22.22%), Histiostoma sp. (22.22%), Lepidoglyphus destructor (16.66%), T. perniciosus(11.11%), Euroglyphus maynei (11.11%), Glycyphagus privatus (11.11%), Cheyletus sp. (11.11%), Tarsonemus sp. (11.11%), and Tetranychus sp. (11.11%). Mite-holding rate of the houses in Erzincan province was found to be 94.44%. The mean number of mites per gram of dust was found to be 18.34. The most common mite species was A. siro, which was followed by D. pteronyssinus.

  7. Status of the Stardust ISPE and the Origin of Four Interstellar Dust Candidates

    Science.gov (United States)

    Westphal, A. J.; Allen, C.; Ansari, A.; Bajt, S.; Bastien, R. S.; Bassim, N.; Bechtel, H. A.; Borg, J.; Brenker, F. E.; Bridges, J.; hide

    2012-01-01

    Some bulk properties of interstellar dust are known through infrared and X-ray observations of the interstellar medium. However, the properties of individual interstellar dust particles are largely unconstrained, so it is not known whether individual interstellar dust particles can be definitively distinguished from interplanetary dust particles in the Stardust Interstellar Dust Collector (SIDC) based only on chemical, mineralogical or isotopic analyses. It was therefore understood from the beginning of the Stardust Interstellar Preliminary Examination (ISPE) that identification of interstellar dust candidates would rest on three criteria - broad consistency with known extraterrestrial materials, inconsistency with an origin as secondary ejecta from impacts on the spacecraft, and consistency, in a statistical sense, of observed dynamical properties - that is, trajectory and capture speed - with an origin in the interstellar dust stream. Here we quantitatively test four interstellar dust candidates, reported previously [1], against these criteria.

  8. Development of data enhancement and display techniques for stream-sediment data collected in the national uranium resource evaluation program of the United States Department of Energy

    International Nuclear Information System (INIS)

    Koch, G.S. Jr.; Howarth, R.J.; Carpenter, R.H.; Schuenemeyer, J.H.

    1979-08-01

    The objective of this study was to combine statistical, mapping, and geological techniques in order to evaluate and appropriately display geochemical data for the identification of uranium associated halos utilizing the NURE hydrogeochemical and stream sediment reconnaissance data base. A set of computer-based procedures implemented in a time-sharing interactive mode on a Control Data Corporation Cyber 70 and 174 computer was developed. Techniques of data analysis are developed. Results of the data analysis for the Southeastern area, Seguin quadrangle, and Pueblo quadrangle are presented. Conclusions are drawn and recommendations are stated

  9. Dust in Snow in the Colorado River Basin: Spatial Variability in Dust Concentrations, Radiative Forcing, and Snowmelt Rates

    Science.gov (United States)

    Skiles, M.; Painter, T.; Deems, J. S.; Landry, C.; Bryant, A.

    2012-12-01

    Since the disturbance of the western US that began with the Anglo settlement in the mid 19th century, the mountain snow cover of the Colorado River Basin (CRB) has been subject to five-fold greater dust loading. This dust deposition accelerates snowmelt through its direct reduction of albedo and its further reduction of albedo by accelerating the growth of snow effective grain size. We have previously quantified the impacts of dust in snow using a 6-year record of dust concentration and energy balance fluxes at the alpine and subalpine towers in the Senator Beck Basin Study Area (SBBSA), San Juan Mountains in southwestern Colorado, USA. Dust loading exhibited interannual variability, and end of year dust concentrations were not necessarily related to the number of dust deposition events. Radiative forcing enhanced springtime melt by 21 to 51 days with the magnitude of advanced loss being linearly related to total dust concentration at the end of snow cover. To expand our understanding of dust on snow deposition patterns we utilize collections of dust concentration at the Colorado Dust on Snow (CODOS) study sites, established in 2009 along the western side of the CRB, to assess spatial variability in dust loading. In situ sampling of dust stratigraphy and concentration occurs twice each season, once over peak snow water equivalent (15 April), and again during melt (15 May). Dust loading occurs at all sites; dust concentrations are always higher in May, vary between sites, and the highest and lowest dust years were 2009 and 2012, respectively. In the absence of regular sampling and energy balance instrumentation these sites do not allow us to quantify the advanced melt due to dust. To facilitate this a new energy balance site, Grand Mesa Study plot (GMSP), was established for water year 2010 in west central Colorado, 150 km north of SBBSA. Back trajectories indicate similar Colorado Plateau dust sources at both SBBSA and GMSP, yet GMSP exhibits slightly lower dust

  10. Study on the alternative mitigation of cement dust spread by capturing the dust with fogging method

    Science.gov (United States)

    Purwanta, Jaka; Marnoto, Tjukup; Setyono, Prabang; Handono Ramelan, Ari

    2017-12-01

    The existence of a cement plant impact the lives of people around the factory site. For example the air quality, which is polluted by dust. Cement plant has made various efforts to mitigate the generated dust, but there are still alot of dust fly inground either from the cement factory chimneys or transportation. The purpose of this study was to conduct a review of alternative mitigation of the spread of dust around the cement plant. This study uses research methods such as collecting secondary data which includes data of rain density, the average rains duration, wind speed and direction as well as data of dust intensity quality around PT. Semen Gresik (Persero) Tbk.Tuban plant. A soft Wind rose file is used To determine the wind direction propensity models. The impact on the spread of dust into the environment is determined using secondary data monitoring air quality. Results of the study is that the mitigation of dust around the cement plant is influenced by natural factors, such as the tendency of wind direction, rain fall and rainy days, and the rate of dust emission from the chimney. The alternative means proposed is an environmental friendly fogging dust catcher.

  11. Interstellar Dust - A Review

    Science.gov (United States)

    Salama, Farid

    2012-01-01

    The study of the formation and the destruction processes of cosmic dust is essential to understand and to quantify the budget of extraterrestrial organic materials. Although dust with all its components plays an important role in the evolution of interstellar physics and chemistry and in the formation of organic materials, little is known on the formation and destruction processes of carbonaceous dust. Laboratory experiments that are performed under conditions that simulate interstellar and circumstellar environments to provide information on the nature, the size and the structure of interstellar dust particles, the growth and the destruction processes of interstellar dust and the resulting budget of extraterrestrial organic molecules. A review of the properties of dust and of the laboratory experiments that are conducted to study the formation processes of dust grains from molecular precursors will be given.

  12. Glass Frit Clumping And Dusting

    International Nuclear Information System (INIS)

    Steimke, J. L.

    2013-01-01

    the dust removed from fresh DWPF Frit 418 while it was being shaken in a small scale LabRAM test was measured. The median size on a volume basis was 7.6 μm and 90% of the frit particles were between 1.6 and 28 μm. The mass of dust collected using this test protocol was much less than 1% of the original frit. 4. Can the dust be removed in a small number of processing steps and without the larger frit particles continuing to spall additional dust sized particles? a. Test results using a LabRAM were inconclusive. The LaRAM performs less efficient particle size separation than the equipment used by Bekeson and Multi-Aspirator. 5. What particle size of frit is expected to create a dust problem? a. The original criterion for creating a dusting problem was those particle sizes that were readily suspended when being shaken. For that criterion calculations and Microtrac size analyses indicated that particles smaller than 37 μm are likely dust generators. Subsequently a more sophisticated criterion for dust problem was considered, particle sizes that would become suspended in the air flow patterns inside the SME and possibly plug the condenser. That size may be larger than 37 μm but has not yet been determined. 6. If particles smaller than 37 μm are removed will bulk dust generation be eliminated? a. Video-taped tests were performed using three gallons each of three types of frit 418, DWPF frit, Bekeson frit and Multi-Aspirator frit. Frit was poured through air from a height of approximately eight feet into a container half filled with water. Pouring Bekeson frit or Multi-Aspirator frit generated markedly less visible dust, but there was still a significant amount, which still has the potential of causing a dust problem. 7. Can completely dry frit be poured into the SME without having dust plug the condenser at the top of the vessel? a. Because of the complexity of air currents inside the SME and the difficulty of defensible size scaling a more prototypical test will be

  13. Nonlinear propagation of dust-acoustic solitary waves in a dusty ...

    Indian Academy of Sciences (India)

    ... Lecture Workshops · Refresher Courses · Symposia · Live Streaming. Home; Journals; Pramana – Journal of Physics; Volume 80; Issue 6. Nonlinear propagation of dust-acoustic solitary waves in a dusty plasma with arbitrarily charged dust and trapped electrons. O Rahman A A Mamun. Volume 80 Issue 6 June 2013 pp ...

  14. Resonant Drag Instabilities in protoplanetary disks: the streaming instability and new, faster-growing instabilities

    Science.gov (United States)

    Squire, Jonathan; Hopkins, Philip F.

    2018-04-01

    We identify and study a number of new, rapidly growing instabilities of dust grains in protoplanetary disks, which may be important for planetesimal formation. The study is based on the recognition that dust-gas mixtures are generically unstable to a Resonant Drag Instability (RDI), whenever the gas, absent dust, supports undamped linear modes. We show that the "streaming instability" is an RDI associated with epicyclic oscillations; this provides simple interpretations for its mechanisms and accurate analytic expressions for its growth rates and fastest-growing wavelengths. We extend this analysis to more general dust streaming motions and other waves, including buoyancy and magnetohydrodynamic oscillations, finding various new instabilities. Most importantly, we identify the disk "settling instability," which occurs as dust settles vertically into the midplane of a rotating disk. For small grains, this instability grows many orders of magnitude faster than the standard streaming instability, with a growth rate that is independent of grain size. Growth timescales for realistic dust-to-gas ratios are comparable to the disk orbital period, and the characteristic wavelengths are more than an order of magnitude larger than the streaming instability (allowing the instability to concentrate larger masses). This suggests that in the process of settling, dust will band into rings then filaments or clumps, potentially seeding dust traps, high-metallicity regions that in turn seed the streaming instability, or even overdensities that coagulate or directly collapse to planetesimals.

  15. Protocols for collection of streamflow, water-quality, streambed-sediment, periphyton, macroinvertebrate, fish, and habitat data to describe stream quality for the Hydrobiological Monitoring Program, Equus Beds Aquifer Storage and Recovery Program, city of Wichita, Kansas

    Science.gov (United States)

    Stone, Mandy L.; Rasmussen, Teresa J.; Bennett, Trudy J.; Poulton, Barry C.; Ziegler, Andrew C.

    2012-01-01

    The city of Wichita, Kansas uses the Equus Beds aquifer, one of two sources, for municipal water supply. To meet future water needs, plans for artificial recharge of the aquifer have been implemented in several phases. Phase I of the Equus Beds Aquifer Storage and Recovery (ASR) Program began with injection of water from the Little Arkansas River into the aquifer for storage and subsequent recovery in 2006. Construction of a river intake structure and surface-water treatment plant began as implementation of Phase II of the Equus Beds ASR Program in 2010. An important aspect of the ASR Program is the monitoring of water quality and the effects of recharge activities on stream conditions. Physical, chemical, and biological data provide the basis for an integrated assessment of stream quality. This report describes protocols for collecting streamflow, water-quality, streambed-sediment, periphyton, macroinvertebrate, fish, and habitat data as part of the city of Wichita's hydrobiological monitoring program (HBMP). Following consistent and reliable methods for data collection and processing is imperative for the long-term success of the monitoring program.

  16. Development of a high resolution interstellar dust engineering model - overview of the project

    Science.gov (United States)

    Sterken, V. J.; Strub, P.; Soja, R. H.; Srama, R.; Krüger, H.; Grün, E.

    2013-09-01

    Beyond 3 AU heliocentric distance, the flow of interstellar dust through the solar system is a dominant component of the total dust population. The modulation of this flux with the solar cycle and the position in the solar system has been predicted by theoretical studies since the seventies. The modulation was proven to exist by matching dust trajectory simulations with real spacecraft data from Ulysses in 1998. The modulations were further analyzed and studies in detail in 2012. The current ESA interplanetary meteoroid model IMEM includes an interstellar dust component, but this component was modelled only with straight line trajectories through the solar system. For the new ESA IMEX model, a high-resolution interstellar dust component is implemented separately from a dust streams module. The dust streams module focuses on dust in streams that was released from comets (cf. Abstract R. Soja). Parallel processing techniques are used to improve computation time (cf. Abstract P. Strub). The goal is to make predictions for the interstellar dust flux as close to the Sun as 1 AU or closer, for future space mission design.

  17. Dust in Libraries

    OpenAIRE

    Mašková, Ludmila

    2013-01-01

    Indoor air pollution in libraries and archives can be harmful for materials stored there. Adverse effects of most of gaseous pollutants are well described, but less is known about dust. Dust particles cover a wide range of sizes and have a variable composition. These characteristics determine their transport to the surfaces and also possible harmful effects. Dust particles not only cause soiling, but coarse particles can damage surfaces by abrasion. Fine particles of acidic or alkaline charac...

  18. Polybrominated diphenyl ethers (PBDEs) in indoor dust and human hair

    Science.gov (United States)

    Kang, Yuan; Wang, Hong Sheng; Cheung, Kwai Chung; Wong, Ming Hung

    2011-05-01

    In the present study, settled workplace dust ( n = 55) from commercial offices, secondary schools, shopping malls, hospitals, electronic factories and manufacturing plants in Hong Kong and settled home dust ( n = 23) from Hong Kong, Shenzhen and Guangzhou, around the Pearl River Delta were collected. Chemical analyses showed that the total PBDEs in workplace dust ranged from 397 to 40,236 ng g -1, with the dust samples from electronic factories having the highest levels (2122-40,236 ng g -1), and dust from homes ranging from 685 to 18,385 ng g -1. The most abundant BDE congeners found were BDE-209 in both workplace dust and home dust, followed by BDE-99 and BDE-47. No significant correlations were observed between total PBDE concentrations in home dust and the age or the house ( p > 0.05), concentrations of BDE-99 + BDE-47 and the number of furniture containing foam ( p > 0.05), and concentrations of BDE-209 and the number of electronic appliances ( p > 0.05). BDE-47, -99, -100 and -183 were found in most of the hair samples collected from occupants of these homes with BDE-47 being the dominant congener (0.86-5.24 ng g -1). The BDE-183 concentration in home dust was significantly correlated with that in human hair ( r = 0.55, p children via non-dietary ingestion of dust (101-404 ng day -1) was higher than that via food consumption (77-190 ng day -1).

  19. SPARCLE: Electrostatic Tool for Lunar Dust Control

    International Nuclear Information System (INIS)

    Clark, P. E.; Curtis, S. A.; Minetto, F.; Cheung, C. Y.; Keller, J. F.; Moore, M.; Calle, C. I.

    2009-01-01

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

  20. Communication plan for windblown dust.

    Science.gov (United States)

    2015-05-01

    Windblown dust events occur in Arizona, and blowing dust has been considered a contributing factor to serious crashes on the : segment of Interstate 10 (I10) between Phoenix and Tucson, as well as on other Arizona roadways. Arizonas dust events...

  1. The occurrence of trace elements in bed sediment collected from areas of varying land use and potential effects on stream macroinvertebrates in the conterminous western United States, Alaska, and Hawaii, 1992-2000

    Science.gov (United States)

    Paul, Angela P.; Paretti, Nicholas V.; MacCoy, Dorene E.; Brasher, Anne M.D.

    2012-01-01

    As part of the National Water-Quality Assessment Program of the U.S. Geological Survey, this study examines the occurrence of nine trace elements in bed sediment of varying mineralogy and land use and assesses the possible effects of these trace elements on aquatic-macroinvertebrate community structure. Samples of bed sediment and macroinvertebrates were collected from 154 streams at sites representative of undeveloped, agricultural, urban, mined, or mixed land-use areas and 12 intermediate-scale ecoregions within the conterminous western United States, Alaska, and Hawaii from 1992 to 2000. The nine trace elements evaluated during this study—arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), mercury (Hg), nickel (Ni), selenium (Se), and zinc (Zn)—were selected on the basis of potential ecologic significance and availability of sediment-quality guidelines. At most sites, the occurrence of these trace elements in bed sediment was at concentrations consistent with natural geochemical abundance, and the lowest concentrations were in bed-sediment samples collected from streams in undeveloped and agricultural areas. With the exception of Zn at sampling sites influenced by historic mining-related activities, median concentrations of all nine trace elements in bed sediment collected from sites representative of the five general land-use areas were below concentrations predicted to be harmful to aquatic macroinvertebrates. The highest concentrations of As, Cd, Pb, and Zn were in bed sediment collected from mined areas. Median concentrations of Cu and Ni in bed sediment were similarly enriched in areas of mining, urban, and mixed land use. Concentrations of Cr and Ni appear to originate largely from geologic sources, especially in the western coastal states (California, Oregon, and Washington), Alaska, and Hawaii. In these areas, naturally high concentrations of Cr and Ni can exceed concentrations that may adversely affect aquatic macroinvertebrates

  2. Dust in Space

    Indian Academy of Sciences (India)

    "They cannot look out far·IThey cannot look in deep. I. But when was that ever a bar ITo any watch they keep?" - Robert Frost, (Neither Out Far Nor In Deep'. Dust grains in space, which absorb and redden starlight, were once considered to be a nuisance for astronomers, but the study of dust has be- come important in ...

  3. Dust in Space

    Indian Academy of Sciences (India)

    Figure B. The concept of photon nlust travel such that the probability of its interacting is interaction length is ex- almost unity. Putting the above probability equal to unity, and plained. writing ~x = 1, the interaction length, 1, is given by 1 = (/n'. How much Dust is there? One can estimate the amount of dust in interstellar space ...

  4. Dust in planetary nebulae

    International Nuclear Information System (INIS)

    Mathis, J.S.

    1978-01-01

    The author's review concentrates on theoretical aspects of dust in planetary nebulae (PN). He considers the questions: how much dust is there is PN; what is its composition; what effects does it have on the ionization structure, on the dynamics of the nebula. (Auth.)

  5. Respirable dust measured downwind during rock dust application.

    Science.gov (United States)

    Harris, M L; Organiscak, J; Klima, S; Perera, I E

    2017-05-01

    The Pittsburgh Mining Research Division of the U.S. National Institute for Occupational Safety and Health (NIOSH) conducted underground evaluations in an attempt to quantify respirable rock dust generation when using untreated rock dust and rock dust treated with an anticaking additive. Using personal dust monitors, these evaluations measured respirable rock dust levels arising from a flinger-type application of rock dust on rib and roof surfaces. Rock dust with a majority of the respirable component removed was also applied in NIOSH's Bruceton Experimental Mine using a bantam duster. The respirable dust measurements obtained downwind from both of these tests are presented and discussed. This testing did not measure miners' exposure to respirable coal mine dust under acceptable mining practices, but indicates the need for effective continuous administrative controls to be exercised when rock dusting to minimize the measured amount of rock dust in the sampling device.

  6. Lunar Dust Mitigation Screens

    Science.gov (United States)

    Knutson, Shawn; Holloway, Nancy

    With plans for the United States to return to the moon, and establish a sustainable human presence on the lunar surface many issues must be successfully overcome. Lunar dust is one of a number of issues with the potential to create a myriad of problems if not adequately addressed. Samples of dust brought back from Apollo missions show it to be soft, yet sharp and abrasive. The dust consists of a variety of morphologies including spherical, angular blocks, shards, and a number of irregular shapes. One of the main issues with lunar dust is its attraction to stick to anything it comes in contact with (i.e. astronauts, equipment, habitats, etc.). Ionized radiation from the sun strikes the moon's surface and creates an electrostatic charge on the dust. Further, the dust harbors van der Waals forces making it especially difficult to separate once it sticks to a surface. During the Apollo missions, it was discovered that trying to brush the lunar dust from spacesuits was not effective, and rubbing it caused degradation of the suit material. Further, when entering the lunar module after moonwalks, the astronauts noted that the dust was so prolific inside the cabin that they inhaled and ingested it, causing at least one of them, Harrison "Jack" Schmidt, to report irritation of the throat and lungs. It is speculated that the dust could also harm an astronaut's nervous and cardiovascular systems, especially during an extended stay. In addition to health issues, the dust can also cause problems by scouring reflective coatings off of thermal blankets, and roughening surfaces of windows and optics. Further, panels on solar cells and photovoltaics can also be compromised due to dust sticking on the surfaces. Lunar dust has the capacity to penetrate seals, interfere with connectors, as well as mechanisms on digging machines, all of which can lead to problems and failure. To address lunar dust issues, development of electrostatic screens to mitigate dust on sur-faces is currently

  7. ATLAS Live: Collaborative Information Streams

    CERN Document Server

    Goldfarb, S; The ATLAS collaboration

    2011-01-01

    I report on a pilot project launched in 2010 focusing on facilitating communication and information exchange within the ATLAS Collaboration, through the combination of digital signage software and webcasting. The project, called ATLAS Live, implements video streams of information, ranging from detailed detector and data status to educational and outreach material. The content, including text, images, video and audio, is collected, visualised and scheduled using digital signage software. The system is robust and flexible, utilizing scripts to input data from remote sources, such as the CERN Document Server, Indico, or any available URL, and to integrate these sources into professional-quality streams, including text scrolling, transition effects, inter and intra-screen divisibility. Information is published via the encoding and webcasting of standard video streams, viewable on all common platforms, using a web browser or other common video tool. Authorisation is enforced at the level of the streaming and at th...

  8. STREAMS - Technology Programme. Yearbook 2003

    International Nuclear Information System (INIS)

    2003-01-01

    The STREAMS Technology Programme addresses municipal waste. Municipal waste is composed of waste from households and small businesses. The programme focuses on five areas Waste prevention, Collection, transportation, and management of waste streams, Waste treatment technologies, Waste recycling into raw materials and new products, Landfill technologies. The development projects of the STREAMS Programme utilize a number of different technologies, such as biotechnology, information technology, materials technology, measurement and analysis, and automation technology. Finnish expertise in materials recycling technologies and related electronics and information technology is extremely high on a worldwide scale even though the companies represent SMEs. Started in 2001, the STREAMS programme has a total volume of 27 million euros, half of which is funded by Tekes. The programme runs through the end of 2004. (author)

  9. Effect of industrial dust on some test organisms

    Energy Technology Data Exchange (ETDEWEB)

    Schuck, H.J.

    1974-01-01

    The effect of industrial dust on the growth of Lepidium sativum Cress and on spore germination and germ-tube development of Botrytis cinerea and Fusarium oxysporum was studied. Lepidium sativum was strongly inhibited and in most cases the fungi were stimulated. The effect was related to the species of trees and the district, where the dust-samples were collected.

  10. Assessment of elemental contamination in road dust using EDXRF

    International Nuclear Information System (INIS)

    Saradhi, I.V.; Sandeep, P.; Pandit, G.G.

    2014-01-01

    Road dust samples were collected in different locations of heavy traffic, medium traffic, express way and industrial areas of Mumbai. The concentrations of various elements (Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn and Pb) in road dust samples were analyzed using EDXRF. The average elemental profile of road dust in Mumbai was comparable with studies carried out in other countries with slight variations. The estimated geo accumulation indices and enrichment factors indicated moderate elemental contamination and enrichment of anthropogenic elements in road dust samples. Factor analysis of elemental data resolved four sources namely crustal, tyre wear, vehicular/industrial emissions and break wear. (author)

  11. Continuous dust monitoring in headings in underground coal mines

    Directory of Open Access Journals (Sweden)

    Kazimierz Lebecki

    2016-01-01

    Full Text Available The article presents hazardous conditions of airborne dust based on the results of measurements of dust concentration taken at work-places at a underground rock-coal face drilled by a heading machine with combined ventilation (suction and forced ventilation with dust collector. The measurements were taken using three methods in order to examine and assess the actual conditions within the excavation subject to the study. The measurement results and conclusions show major difficulties in achieving MAC levels. Research conclusions indicate the low efficiency of collective and personal measures applied to protect against dust harmful to health as well as the need to improve them.

  12. Laboratory and field evaluation of instantaneous-reading dust instruments

    International Nuclear Information System (INIS)

    Thompson, E.M.; Treaftis, H.N.; Tomb, T.F.

    1984-01-01

    A study was conducted to evaluate two instantaneous-reading dust monitors that utilize the attenuation of beta rays to determine respirable mass-dust concentrations. The one monitor utilizes impaction to deposit the sample on a mylar substrate while the other monitor collects the sample on a glass fiber filter. Measurements obtained using test aerosols of coal, limestone, and silica dusts were compared to measurements obtained with the approved personal coal mine dust sampler. Instrument linearity was synthetically checked using mylar and formvar films of varying thickness. The monitor employing the glass fiber filters was also tested in underground coal mines

  13. Carbon Dust Filtration in Three Different Nuclear Process Environments: A comparison the challenges Carbon Dust Filtration Presents Under Different Process Conditions

    International Nuclear Information System (INIS)

    Chadwick, Chris

    2014-01-01

    Inits thirty five years of activity as an engineering company in nuclear filtration sector, the Porvair Filtration Group has experienced several demands to remove of Carbon/graphite dust from several nuclear gas streams. Of particular interest among those applications are, and those to be reported upon in this paper, are; • High temperature, high pressure, high DP resistant (high strength) filters operating in the CO2 environment of the UK fleet of AGR (Advanced Gas-Cooled Reactors) • Removing gross quantities of Carbon dust from the exhaust stream of a radioactive, nuclear organics decomposition, waste process • High pressure Helium filtration to remove Carbon dust for a gas flow associated with the Fuel Handling System in the High Temperature Reactor programme Each process is different from the other and presents its own unique problems. The paper will present to this conference the very different properties Carbon dust appears to exhibit in each of these very different applications, and to discuss the effects those significant differences had/have on Porvair’s responses to each application. An interesting comparison will be made of the substantial difference between the performance of the UK AGR filters and those used in the US for the removal of decomposed organics, and the significantly different properties the Carbon appears to exhibit in each unique set of conditions Two UK AGR stations which are described are taken out of service when their bypass blowdown filters reach an operating DP of about 700mB DP (starting at a clean DP of around 100mB) to enable their replacement. The used filter assemblies are lifted from their housings and placed in an active storage area. Analysis of the used filter assemblies has shown that, where they are observable, they appear to be pristine with no apparent surface discolouration. It is only when examined under magnification that it becomes obvious that the filter medium, under the outer layer of fibres, is coated in

  14. Polyfluoroalkyl chemicals in house dust

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Kayoko [Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Hwy., Mailstop F53, Atlanta, GA 30341 (United States); Calafat, Antonia M., E-mail: acalafat@cdc.gov [Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Hwy., Mailstop F53, Atlanta, GA 30341 (United States); Needham, Larry L. [Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Hwy., Mailstop F53, Atlanta, GA 30341 (United States)

    2009-07-15

    We developed a high throughput analytical method using on-line solid phase extraction coupled with isotope dilution high-performance liquid chromatography-tandem mass spectrometry (on-line SPE-HPLC-MS/MS) to simultaneously determine the concentrations of 17 polyfluoroalkyl chemicals (PFCs) in house dust. The sample preparation includes dispersion of the dust samples in 0.1 M formic acid:MeOH (1:1), followed by agitation and filtration, addition of the isotope-labeled internal standard solution to the filtrate, and analysis by on-line SPE-HPLC-MS/MS. The limits of quantitation were <4.0 ng/g. The method accuracies ranged between 73.2% and 100.2% for the different analytes at two spike levels. We confirmed the validity of the method by analyzing 39 household dust samples collected in 2004. Of the 17 PFCs measured, 6 of them-perfluorobutane sulfonate (PFBuS), N-ethyl-perfluorooctane sulfonamide, 2-(N-ethyl-perfluorooctane sulfonamido) acetic acid (Et-PFOSA-AcOH), 2-(N-methyl-perfluorooctane sulfonamido) ethanol (Me-PFOSA-EtOH), perfluorohexane sulfonate (PFHxS), and perfluorooctane sulfonate (PFOS)-had detection frequencies >70%. We detected PFOS, PFBuS, and PFHxS at the highest median concentration, followed by Et-PFOSA-AcOH and Me-PFOSA-EtOH.

  15. Electronic design of air dust concentration gauge

    International Nuclear Information System (INIS)

    Machaj, B.; Strzalkowski, J.; Krawczynska, B.

    1993-01-01

    A new version of isotope dust concentration gauge for monitoring airborne dust pollution of air employs a ready made personal computer as the control and processing unit in the gauge instead of specialized electronics. That solution of the gauge reduces the needed specialized electronics to a simple computer interface coupling the computer to the measuring head. This also reduced electronics of the measuring head itself, i.e. GM detector circuit, power supplies and electronic circuits to switch on/off driving motors. The functioning and operation of the gauge is controlled by the computer program that can be easily modified if needed. The computer program for the gauge enables automatic measurements of dust concentration. Up to fifty measuring cycles can be easily programmed for a day. The results of measurements are presented in the form of data collection, diagram of dust concentration distribution during one day, diagram of dust distribution during 30 successive days or diagram of average dust concentration distribution during a day which may be computed by combining data of the selected number of measurements. Recalibration of the gauge and checking up of the gauge are also carried out under the program control. (author). 6 refs, 9 figs

  16. Geochemical data for stream-sediment, heavy-mineral-concentrate and rock samples collected from the Fortyseven Creek gold-arsenic-antimony-tungsten prospect, southwestern Alaska

    Science.gov (United States)

    Gray, John E.; Lee, G.K.; O'Leary, R. M.; Theodorakos, P.M.

    1999-01-01

    In the summer of 1991, we conducted a reconnaissance geochemical survey around the Fortyseven Creek Au-As-Sb-W prospect that is located in the southwestern part of the Sleetmute quadrangle. At that time, this project was a small part of a more comprehensive Alaska Mineral Resource Assessment Program (AMRAP) study of the Sleemute quadrangle. AMRAP studies were conducted by the U.S. Geological Survey (USGS) to fulfill requirements of the Alaska National Interests Lands Conservation Act (Public Law 96-487, 1980) to survey certain federal lands to determine their mineral potential. Although AMRAP is no longer in operation, this study represents a small topical study that was conducted during the Sleetmute quadrangle AMRAP study. The objective of the Fortyseven Creek work was to characterize the geochemistry of samples collected downstream from the Fortyseven Creek prospect, as well as mineralized and altered rock samples collected from the prospect. In this report, we describe the samples collected in 1991, the methods used for the analysis of the samples, and the geochemical data for these samples. The data in this report are also available in digital form on computer diskette in Gray and others (1999). An interpretation of these data appears in Gray and others (1998).

  17. Influence of dust particles on DC glow discharge plasma

    Science.gov (United States)

    Liang, Yonggan; Yuan, Chengxun; Li, Hui; Tian, Ruihuan; Wu, Jian; Kudryavtsev, A. A.; Zhou, Zhongxiang; Tian, Hao

    2018-02-01

    The effect of dust particles on DC glow discharge plasma parameters is studied numerically through the development of a self-consistent model based on the extended fluid approach. The orbital motion limited theory and collision enhanced collection approximation are employed to describe the charging processes of dust particles with various sizes and densities. The uniform distribution of dust particles in plasma and the instantaneous charging process were assumed during simulations. The influence of dust particle size rd and density Nd on gas discharge and dust particle parameters is investigated systematically. It is shown that the plasma parameters can be affected obviously by the dust particles. The increase in the values of rd and Nd leads to the decrease in the dust particle charge number, electron, and ion density. Meanwhile, the appearance of dust particles leads to an obvious increase in the averaged plasma electric field and electron temperature to sustain the discharge in the dust region. The dust particles are proven to be a very efficient way to artificially manipulate gas discharge parameters.

  18. Effects of road dust on the growth characteristics of Sophora japonica L. seedlings.

    Science.gov (United States)

    Bao, Le; Qu, Laiye; Ma, Keming; Lin, Lin

    2016-08-01

    Road dust is one of the most common pollutants and causes a series of negative effects on plant physiology. Dust's impacts on plants can be regarded as a combination of load, composition and grain size impacts on plants; however, there is a lack of integrated dust effect studies involving these three aspects. In our study, Sophora japonica seedlings were artificially dusted with road dust collected from the road surface of Beijing so that we could study the impacts of this dust on nitrogen/carbon allocation, biomass allocation and photosynthetic pigments from the three aspects of composition, load and grain size. The results showed that the growth characteristics of S. japonica seedlings were mostly influenced by dust composition and load. Leaf N, root-shoot ratio and chlorophyll a/b were significantly affected by dust composition and load; leaf C/N, shoot biomass, total chlorophyll and carotenoid were significantly affected by dust load; stem N and stem C/N were significantly affected by dust composition; while the dust grain size alone did not affect any of the growth characteristics. Road dust did influence the growth characteristics more extensively than loam. Therefore, a higher dust load could increase the differences between road dust and loam treatments. The elements in dust are well correlated to the shoot N, shoot C/N, and root-shoot ratio of S. japonica seedlings. This knowledge could benefit the management of urban green spaces. Copyright © 2016. Published by Elsevier B.V.

  19. Fine dust filtration using a metal fiber bed.

    Science.gov (United States)

    Lee, Kyung Mi; Lee, Young Sup; Jo, Young Min

    2006-08-01

    A bed-type filter composed of thin metal alloy fiber was closely examined with dust capturing in cold and hot runs. The investigation of an individual mechanism across the filter bed indicated that the aerated dust could be initially collected by depth filtration, and after a while, surface filtration dominated the overall dust collection. The present metal fiber bed was comparable to the conventional ceramic filters because of its good collection efficiency with low pressure drop. It also showed potential to be used as a prefilter in a diesel exhaust trapping system.

  20. Organic matter determination for street dust in Delhi.

    Science.gov (United States)

    Shandilya, Kaushik K; Khare, Mukesh; Gupta, A B

    2013-06-01

    The organic matter of street dust is considered as one of the causes for high human mortality rate. To understand the association, the street dust samples were collected from four different localities (industrial, residential, residential-commercial, and commercial) situated in the greater Delhi area of India. The loss-on-ignition method was used to determine the organic matter (OM) content in street dust. The OM content, potassium, calcium, sulfate, and nitrate concentrations of street dust in Delhi, India is measured to understand the spatial variation. Correlation analysis, analysis of variance, and factor analysis were performed to define the sources. The dust OM level ranges from 2.63 to 10.22 %. It is found through correlation and factor analysis that OM is primarily contributed from secondary aerosol and vehicular exhaust. The OM levels suggest that the use of a residential-commercial site for commercial purposes is polluting the street dust and creating the environmental and human health problems.

  1. Quantifying Anthropogenic Dust Emissions

    Science.gov (United States)

    Webb, Nicholas P.; Pierre, Caroline

    2018-02-01

    Anthropogenic land use and land cover change, including local environmental disturbances, moderate rates of wind-driven soil erosion and dust emission. These human-dust cycle interactions impact ecosystems and agricultural production, air quality, human health, biogeochemical cycles, and climate. While the impacts of land use activities and land management on aeolian processes can be profound, the interactions are often complex and assessments of anthropogenic dust loads at all scales remain highly uncertain. Here, we critically review the drivers of anthropogenic dust emission and current evaluation approaches. We then identify and describe opportunities to: (1) develop new conceptual frameworks and interdisciplinary approaches that draw on ecological state-and-transition models to improve the accuracy and relevance of assessments of anthropogenic dust emissions; (2) improve model fidelity and capacity for change detection to quantify anthropogenic impacts on aeolian processes; and (3) enhance field research and monitoring networks to support dust model applications to evaluate the impacts of disturbance processes on local to global-scale wind erosion and dust emissions.

  2. Beyond Orbital-Motion-Limited theory effects for dust transport in tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Delzanno, Gian Luca [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tang, Xianzhu [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-05-29

    Dust transport in tokamaks is very important for ITER. Can many kilograms of dust really accumulate in the device? Can the dust survive? The conventional dust transport model is based on Orbital-Motion-Limited theory (OML). But OML can break in the limit where the dust grain becomes positively charged due to electron emission processes because it overestimates the dust collected power. An OML+ approximation of the emitted electrons trapped/passing boundary is shown to be in good agreement with PIC simulations.

  3. Assessing the human health risk for aluminium, zinc and lead in outdoor dusts collected in recreational sites used by children at an industrial area in the western part of the Bassin Minier de Provence, France

    Science.gov (United States)

    Reis, A. P.; Patinha, C.; Noack, Y.; Robert, S.; Dias, A. C.; Ferreira da Silva, E.

    2014-11-01

    The Western part of the “Bassin Minier de Provence”, a former coal mining area, is still occupied by old polluting industries such as a coal-fired power plant and an alumina factory. In 2011 a preliminary outdoor dust survey was carried out in the area as the first step to an exposure and health risk assessment study. Dust samples were taken at 19 sites distributed across the study area, depending on the location of recreational areas used by children to play outdoors. Pseudo-total concentrations of Al, Zn and Pb were determined by ICP-MS and bioaccessible concentrations were estimated using the Unified BARGE Method. Exposure was calculated according to a scenario evaluation approach for dust ingestion and dermal contact routes. Estimation of health risk for exposure to Al, Zn and Pb in outdoor dust was based on the summation of individual risks for the oral and dermal routes. Results show that Al occurs in very high concentrations but mainly innon-bioaccessible forms, especially near the alumina plant. Zinc and Pb occur in low-average levels but mainly in bioaccessible forms. The estimated potential risk decreases according to Pb ≫ Al > Zn and is lower for the ingestion route. The preliminary results presented in this study indicate that, for Al and Zn, the outdoor dusts of the BMP represent an acceptable risk to children's health. However, the estimated hazard quotients suggest that there is some health risk associated to environmental Pb.

  4. Investigations of Wind/WAVES Dust Impacts

    Science.gov (United States)

    St Cyr, O. C.; Wilson, L. B., III; Rockcliffe, K.; Mills, A.; Nieves-Chinchilla, T.; Adrian, M. L.; Malaspina, D.

    2017-12-01

    The Wind spacecraft launched in November 1994 with a primary goal to observe and understand the interaction between the solar wind and Earth's magnetosphere. The waveform capture detector, TDS, of the radio and plasma wave investigation, WAVES [Bougeret et al., 1995], onboard Wind incidentally detected micron-sized dust as electric field pulses from the recollection of the impact plasma clouds (an unintended objective). TDS has detected over 100,000 dust impacts spanning almost two solar cycles; a dataset of these impacts has been created and was described in Malaspina & Wilson [2016]. The spacecraft continues to collect data about plasma, energetic particles, and interplanetary dust impacts. Here we report on two investigations recently conducted on the Wind/WAVES TDS database of dust impacts. One possible source of dust particles is the annually-recurring meteor showers. Using the nine major showers defined by the American Meteor Society, we compared dust count rates before, during, and after the peak of the showers using averaging windows of varying duration. However, we found no statistically significant change in the dust count rates due to major meteor showers. This appears to be an expected result since smaller grains, like the micron particles that Wind is sensitive to, are affected by electromagnetic interactions and Poynting-Robertson drag, and so are scattered away from their initial orbits. Larger grains tend to be more gravitationally dominated and stay on the initial trajectory of the parent body so that only the largest dust grains (those that create streaks as they burn up in the atmosphere) are left in the orbit of the parent body. Ragot and Kahler [2003] predicted that coronal mass ejections (CMEs) near the Sun could effectively scatter dust grains of comparable size to those observed by Wind. Thus, we examined the dust count rates immediately before, during, and after the passage of the 350 interplanetary CMEs observed by Wind over its 20+ year

  5. Global perspectives on the urban stream syndrome

    Science.gov (United States)

    Roy, Allison; Booth, Derek B.; Capps, Krista A.; Smith, Benjamin

    2016-01-01

    Urban streams commonly express degraded physical, chemical, and biological conditions that have been collectively termed the “urban stream syndrome”. The description of the syndrome highlights the broad similarities among these streams relative to their less-impaired counterparts. Awareness of these commonalities has fostered rapid improvements in the management of urban stormwater for the protection of downstream watercourses, but the focus on the similarities among urban streams has obscured meaningful differences among them. Key drivers of stream responses to urbanization can vary greatly among climatological and physiographic regions of the globe, and the differences can be manifested in individual stream channels even through the homogenizing veneer of urban development. We provide examples of differences in natural hydrologic and geologic settings (within similar regions) that can result in different mechanisms of stream ecosystem response to urbanization and, as such, should lead to different management approaches. The idea that all urban streams can be cured using the same treatment is simplistic, but overemphasizing the tremendous differences among natural (or human-altered) systems also can paralyze management. Thoughtful integration of work that recognizes the commonalities of the urban stream syndrome across the globe has benefitted urban stream management. Now we call for a more nuanced understanding of the regional, subregional, and local attributes of any given urban stream and its watershed to advance the physical, chemical, and ecological recovery of these systems.

  6. The aeolian dust accumulation curve

    NARCIS (Netherlands)

    Goossens, D.

    2001-01-01

    This article presents a simple physical concept of aeolian dust accumulation, based on the behaviour of the subprocesses of dust deposition and dust erosion. The concept is tested in an aeolian dust wind tunnel. The agreement between the accumulation curve predicted by the model and the accumulation

  7. Quantitation of house dust mites and house dust mite allergens in the microenvironment of dogs.

    Science.gov (United States)

    Randall, Amy; Hillier, Andrew; Cole, Lynette K; Kwochka, Kenneth W; Needham, Glen; Wassom, Donald L

    2003-10-01

    To quantitate the density of Dermatophagoides farinae and D pteronyssinus and concentrations of house dust mite (HDM) allergens (Der f 1, Der p 1, and Group 2 allergens) in the indoor microenvironment of dogs. Sample Population-50 homes in Columbus, Ohio. n each home, samples of dust were collected from 3 locations in which dogs spent most time. Whenever possible, the species of mites collected was identified. Mite density (mites/g of dust) was assessed, and allergen concentrations were assayed by standardized ELISAs. Relative humidity and temperature in each home were monitored during a 5-day period. Characteristics of homes and sample sources were evaluated. Dust samples from all 50 homes contained > or = 1 HDM allergen; Der f 1 and Der p 1 were detected in 100 and 74% of homes, respectively. Fifteen homes had HDMs; compared with D pteronyssinus, D farinae was found more commonly (14/15 homes) and at a higher density. Basements, homes without central air-conditioning, and dog beds that were > or = 1 year old had high HDM allergen concentrations. Homes with > or = 2 microg of Der f 1 or Group 2 allergens/g of dust or > or = 100 mites/g of dust were significantly more likely to have a maximum relative humidity > or = 75%. Results indicate the presence of HDMs and HDM allergens in the specific microenvironment of dogs in homes. Factors associated with high levels of exposure were identified, which may be associated with increased risk for sensitization and development of atopic diseases.

  8. Temporal variability of the elemental composition in urban street dust.

    Science.gov (United States)

    Vermette, S J; Irvine, K N; Drake, J J

    1991-07-01

    Urban Street dust is recognized as a source of urban air and runoff degradation. This paper takes a preliminary step toward a better understanding of temporal variability in street dust chemistry and of the controlling mechanisms. Street dust samples, collected over four seasons in the city of Hamilton, Canada, show a variability dependent on element and source-anthropogenic sources exhibiting the greatest temporal variability. In addition, elements attributed to common sources exhibit similar temporal patterns. The use of 'generic' or even one-time samples may seriously misrepresent the elemental make-up of urban street dust. Based on the samples collected in this study, a number of questions/insights are posed to further the study of street dust temporal variability.

  9. Dust filter testing

    International Nuclear Information System (INIS)

    Dupoux, J.

    1975-01-01

    The composition of dust filters used in cleanup systems for radioactive gaseous effluents is described as well as the technical controls, especially efficiency measured by a soda fluorescein aerosol [fr

  10. Dust mite (image)

    Science.gov (United States)

    This is a magnified photograph of a dust mite. Mites are carriers (vectors) of many important diseases including typhus (scrub and murine) and rickettsialpox. (Image courtesy of the Centers for Disease Control ...

  11. Nano Dust Analyzer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a new highly sensitive instrument to confirm the existence of the so-called nano-dust particles, characterize their impact parameters, and...

  12. "Kicking Up Some Dust": An Experimental Investigation Relating Lunar Dust Erosive Wear to Solar Power Loss

    Science.gov (United States)

    Mpagazehe, Jeremiah N.; Street, Kenneth W., Jr.; Delgado, Irebert R.; Higgs, C. Fred, III

    2013-01-01

    The exhaust from retrograde rockets fired by spacecraft landing on the Moon can accelerate lunar dust particles to high velocities. Information obtained from NASA's Apollo 12 mission confirmed that these high-speed dust particles can erode nearby structures. This erosive wear damage can affect the performance of optical components such as solar concentrators. Solar concentrators are objects which collect sunlight over large areas and focus the light into smaller areas for purposes such as heating and energy production. In this work, laboratory-scale solar concentrators were constructed and subjected to erosive wear by the JSC-1AF lunar dust simulant. The concentrators were focused on a photovoltaic cell and the degradation in electrical power due to the erosive wear was measured. It was observed that even moderate exposure to erosive wear from lunar dust simulant resulted in a 40 percent reduction in power production from the solar concentrators.

  13. Effect of dust size distribution and dust charge fluctuation on dust ion ...

    Indian Academy of Sciences (India)

    2016-06-17

    Jun 17, 2016 ... Dusty plasma; dust-acoustic shock wave; dust size distribution; adiabatic dust charge variation; negative ions. PACS Nos 52.27.Lw; 52.35.Tc; 52.35.Mw. 1. Introduction. The low-frequency dust ion-acoustic waves are typi- cal acoustic modes in unmagnetized and collisionless dusty plasma with a weak ...

  14. Effect of dust size distribution and dust charge fluctuation on dust ion ...

    Indian Academy of Sciences (India)

    The effects of dust size distribution and dust charge fluctuation of dust grains on the small but finite amplitude nonlinear dust ion-acoustic shock waves, in an unmagnetized multi-ion dusty plasma which contains negative ions, positive ions and electrons, are studied in this paper. A Burgers equation and its stationary ...

  15. Oil refinery dusts: morphological and size analysis by TEM

    Energy Technology Data Exchange (ETDEWEB)

    Sielicki, Przemyslaw; Janik, Helena; Guzman, Agnieszka [Gdansk University of Technology, Department of Polymer Technology, Chemical Faculty, Gdansk (Poland); Broniszewski, Mieczyslaw [Environmental Protection Office, Lotos Group, Gdansk (Poland); Namiesnik, Jacek [Gdansk University of Technology, Department of Analytical Chemistry, Chemical Faculty, Gdansk (Poland)

    2011-03-15

    The objectives of this work were to develop a means of sampling atmospheric dusts on the premises of an oil refinery for electron microscopic study to carry out preliminary morphological analyses and to compare these dusts with those collected at sites beyond the refinery limits. Carbon and collodion membranes were used as a support for collection of dust particles straight on transmission electron microscopy (TEM) grids. Micrographs of the dust particles were taken at magnifications from x 4,000 to x 80,000 with a Tesla BS500 transmission electron microscope. Four parameters were defined on the basis of the micrographs: surface area, Feret diameter, circumference, and shape coefficient. The micrographs and literature data were used to classify the atmospheric dusts into six groups: particles with an irregular shape and rounded edges; particles with an irregular shape and sharp edges; soot and its aggregates; spherical particles; singly occurring, ultrafine dust particles; and particles not allocated to any of the previous five groups. The types of dusts found in all the samples were similar, although differences did exist between the various morphological parameters. Dust particles with the largest Feret diameter were present in sample 3 (mean, 0.739 {mu}m) - these were collected near the refinery's effluent treatment plant. The particles with the smallest diameter were found in the sample that had been intended to be a reference sample for the remaining results (mean, 0.326 {mu}m). The dust particles collected in the refinery had larger mean Feret diameters, even 100% larger, than those collected beyond it. Particles with diameters from 0.1 to 0.2 {mu}m made up the most numerous group in all the samples collected in the refinery. (orig.)

  16. STARDUST DUST COLLECTOR GEOMETRY V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — Data set describing the geometry and orientations of the spacecraft and the collector plate during the two interstellar dust collection phases and the Wild 2...

  17. 'Nuisance Dust' - a Case for Recalibration?

    Science.gov (United States)

    Datson, Hugh; Marker, Brian

    2013-04-01

    This paper considers the case for a review and recalibration of limit values and acceptability criteria for 'nuisance dust', a widely encountered but poorly defined and regulated aspect of particulate matter pollution. Specific dust fractions such as PM10 and asbestiforms are well characterised and have limit values enshrined in legislation. National, and international, limit values for acceptable concentrations of PM10 and other fractions of particulate matter have been defined and agreed. In the United Kingdom (UK), these apply to both public and workplace exposures. By contrast, there is no standard definition or universal criteria against which acceptable levels for 'nuisance dust' can be assessed. This has implications for land-use planning and resource utilisation. Without meaningful limit values, inappropriate development might take place too near to residential dwellings or land containing economically important mineral resources may be effectively sterilised. Furthermore, the expression 'nuisance dust' is unhelpful in that 'nuisance' has a specific meaning in environmental law whilst 'nuisance dust' is often taken to mean 'generally visible particulate matter'. As such, it is associated with the social and broader environmental impacts of particulate matter. PM10 concentrations are usually expressed as a mass concentration over time. These can be determined using a range of techniques. While results from different instruments are generally comparable, data obtained from alternative methods for measuring 'nuisance dust' are rarely interchangeable. In the UK, many of the methods typically used are derived from approaches developed under the HMIP (Her Majesty's Inspectorate of Pollution) regime in the 1960s onwards. Typical methods for 'nuisance dust' sampling focus on measurement of dust mass (from the weight of dust collected in an open container over time) or dust soiling (from loss of reflectance and or obscuration of a surface discoloured by dust over

  18. Regularities of dust formation during stone cutting for construction works

    Directory of Open Access Journals (Sweden)

    V.G. Lebedev

    2016-09-01

    Full Text Available When cutting stone, a large amount of dust release, which is a mixture of small, mostly sharp, mineral particles. Shallow dry dust with inhalation causes the pathological changes in organs that are a consequence of infiltration of acute and solids particles. Despite the importance of this problem, the questions of dust generation during the various working processes and its fractions distribution are practically not considered. This determines the time of dust standing in the air and its negative impact on a person. Aim: The aim of this research is to study the process of dusting during stones cutting and dust distribution on fractions regularities and quantification of dust formation process in order to improve the production equipment, staff individual and collective safety equipment. Materials and Methods: Many types of cutting can be divided into two types - a “dry” cutting and cutting with fluid. During “dry” cutting a dust represents a set of micro-chips which are cut off by the abrasive grains. The size of such chips very small: from a micrometer to a few micrometers fraction. Thus, the size of chips causes the possibility of creating dust slurry with low fall velocity, and which is located in the working space in large concentrations. Results: The following characteristic dependences were obtained as a result of research: dependence of the dust fall from the size of the dust particles, size of dust particles from minute feeding and grain range wheel, the specific amount of dust from the number of grit abrasive wheel and the temperature of the dust particles from the feeding at wheel turnover. It was shown that the distribution of chips (dust by size will request of a normal distribution low. Dimensions of chips during cut are in the range of 0.4...6 μm. Thus, dust slurry is formed with time of particles fall of several hours. This creates considerable minute dust concentration - within 0.28∙10^8...1.68∙10^8 units/m3.

  19. [Gohieria fuscafound in dust of air-conditioner filters].

    Science.gov (United States)

    Qiang, Chai; Xiao-Dong, Zhan; Wei, Guo; Chao-Pin, Li

    2017-09-25

    To investigate the pollution status of Gohieria fusca in the air conditioner-filters of different places in Wuhu City. The dust samples were collected from the filters of air-conditioners in dining rooms, shopping malls, hotels and households between June and September, 2013, and G. fusca was detected in the dust samples. There were 430 dust samples collected and 98 were G. fusca positive with the breeding rate of 22.79%. The difference of breeding rates of G. fusca were statistically significant among the different places ( χ 2 =18.294, P air-conditioner filters in Wuhu City gravely.

  20. Interplanetary Dust Particles

    Science.gov (United States)

    Bradley, J. P.

    2003-12-01

    micrometeorites) containing layer silicates indicative of parent-body aqueous alteration and the more distant anhydrous P and D asteroids exhibiting no evidence of (aqueous) alteration (Gradie and Tedesco, 1982). This gradation in spectral properties presumably extends several hundred AU out to the Kuiper belt, the source region of most short-period comets, where the distinction between comets and outer asteroids may simply be one of the orbital parameters ( Luu, 1993; Brownlee, 1994; Jessberger et al., 2001). The mineralogy and petrography of meteorites provides direct confirmation of aqueous alteration, melting, fractionation, and thermal metamorphism among the inner asteroids ( Zolensky and McSween, 1988; Farinella et al., 1993; Brearley and Jones, 1998). Because the most common grains in the ISM (silicates and carbonaceous matter) are not as refractory as those found in meteorites, it is unlikely that they have survived in significant quantities in meteorites. Despite a prolonged search, not a single presolar silicate grain has yet been identified in any meteorite.Interplanetary dust particles (IDPs) are the smallest and most fine-grained meteoritic objects available for laboratory investigation (Figure 1). In contrast to meteorites, IDPs are derived from a broad range of dust-producing bodies extending from the inner main belt of the asteroids to the Kuiper belt (Flynn, 1996, 1990; Dermott et al., 1994; Liou et al., 1996). After release from their asteroidal or cometary parent bodies the orbits of IDPs evolve by Poynting-Robertson (PR) drag (the combined influence of light pressure and radiation drag) ( Dermott et al., 2001). Irrespective of the location of their parent bodies nearly all IDPs under the influence of PR drag can eventually reach Earth-crossing orbits. IDPs are collected in the stratosphere at 20-25 km altitude using NASA ER2 aircraft ( Sandford, 1987; Warren and Zolensky, 1994). Laboratory measurements of implanted rare gases, solar flare tracks ( Figure 2

  1. Lead contamination in street dust in Hong Kong.

    Science.gov (United States)

    Ho, Y B

    1979-03-01

    Lead levels were generally found to be high in road-side dust samples collected from different sites throughout the Island of Hong Kong during winter 1977-78. Considerable differences in the concentration of lead amongst these sites were detected but such differences bore no direct relationship to the traffic volumes of the sites from which the samples were collected. Different districts within the city varied widely in the mean concentration of lead in their road-side dust samples.

  2. Particle-associated contaminants in street dust, parking lot dust, soil, lake-bottom sediment, and suspended and streambed sediment, Lake Como and Fosdic Lake watersheds, Fort Worth, Texas, 2004

    Science.gov (United States)

    Wilson, Jennifer T.; Van Metre, Peter C.; Werth, Charles J.; Yang, Yanning

    2006-01-01

    A previous study by the U.S. Geological Survey of impaired water bodies in Fort Worth, Texas, reported elevated but variable concentrations of particle-associated contaminants (PACs) comprising chlorinated hydrocarbons, polycyclic aromatic hydrocarbons, and trace elements in suspended and bed sediment of lakes and streams affected by urban land use. The U.S. Geological Survey, in cooperation with the City of Fort Worth, collected additional samples during October 2004 to investigate sources of PACs in the watersheds of two impaired lakes: Lake Como and Fosdic Lake. Source materials and aquatic sediment were sampled and analyzed for PACs. Source materials sampled consisted of street dust and soil from areas with residential and commercial land use and parking lot dust from sealed and unsealed parking lots. Aquatic sediment sampled consisted of bottom-sediment cores from the two lakes and suspended and streambed sediment from the influent stream of each lake. Samples were analyzed for chlorinated hydrocarbons (organochlorine pesticides and polychlorinated biphenyls), polycyclic aromatic hydrocarbons, major and trace elements, organic carbon, grain size, and radionuclides.

  3. Collection methods, data compilation, and lessons learned from a study of stream geomorphology associated with riparian cattle grazing along the Fever River, University of Wisconsin- Platteville Pioneer Farm, Wisconsin, 2004–11

    Science.gov (United States)

    Peppler, Marie C.; Fitzpatrick, Faith A.

    2018-03-09

    Stream geomorphic characteristics were monitored along a 0.8-mile reach of the Fever River in the Driftless Area of southwestern Wisconsin from 2004 to 2011 where cattle grazed in paddocks along the riverbank at the University of Wisconsin-Platteville’s Pioneer Farm. The study reach encompassed seven paddocks that covered a total of 30 acres on both sides of the river. Monitoring data included channel crosssection surveys, eroding bank measurements and photograph points, erosion-pin measurements, longitudinal profile surveys, measurements of the volume of soft sediment in the channel, and repeated time-lapse photographs. Characteristics were summarized into subreaches by use of a geographic information system. From 2004 to 2007, baseline monitoring was done to identify geomorphic conditions prior to evaluating the effects of management alternatives for riparian grazing. Subsequent to the full-scale baseline monitoring, additional data were collected from 2007 to 2011. Samples of eroding bank and in-channel soft sediment were collected and analyzed for dry bulk density in 2008 for use in a sediment budget. One of the pastures was excluded from cattle grazing in the fall of 2007; in 2009 channel cross sections, longitudinal profiles, erosion-pin measurements, photographs, and a soft sediment survey were again collected along the full 0.8-mile reach for a comparison to baseline monitoring data. Channel cross sections were surveyed a final time in 2011. Lessons learned from bank monitoring with erosion pins were most numerous and included the need for consistent tracking of each pin and whether there was deposition or erosion, timing of measurements and bank conditions during measurements (frozen, postflood), and awareness of pins loosening in place. Repeated freezing and thawing of banks and consequential mass wasting and jointing enhance fluvial erosion. Monitoring equipment in the paddocks was kept flush to the ground or located high on posts to avoid injuring the

  4. Problems in monitoring dust levels within mines.

    Science.gov (United States)

    Hearl, F J; Hewett, P

    1993-01-01

    The collection of dust samples in mines is a multifaceted problem. Initially, one must define the situation being sampled and the purpose of the sampling in order to establish an appropriate sampling plan, including specification of the type of mining process (surface vs. underground, metal vs. nonmetal vs. coal) as well as the mining system employed (equipment). The next step is to decide the nature of the hazard being monitored (i.e., dust depositing in alveolar air spaces entails use of respirable dust sampling, upper airways entails thoracic-fraction sampler, and systemic effects call for an inhalable-fraction sampler) in order to select the appropriate sampler. Deciding on a particular sampling strategy is a complex issue involving federal regulations as well as compliance.

  5. Fractal dust grains in plasma

    International Nuclear Information System (INIS)

    Huang, F.; Peng, R. D.; Liu, Y. H.; Chen, Z. Y.; Ye, M. F.; Wang, L.

    2012-01-01

    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.

  6. Interaction between stream temperature, streamflow, and groundwater exchanges in alpine streams

    Science.gov (United States)

    Constantz, James E.

    1998-01-01

    Four alpine streams were monitored to continuously collect stream temperature and streamflow for periods ranging from a week to a year. In a small stream in the Colorado Rockies, diurnal variations in both stream temperature and streamflow were significantly greater in losing reaches than in gaining reaches, with minimum streamflow losses occurring early in the day and maximum losses occurring early in the evening. Using measured stream temperature changes, diurnal streambed infiltration rates were predicted to increase as much as 35% during the day (based on a heat and water transport groundwater model), while the measured increase in streamflow loss was 40%. For two large streams in the Sierra Nevada Mountains, annual stream temperature variations ranged from 0° to 25°C. In summer months, diurnal stream temperature variations were 30–40% of annual stream temperature variations, owing to reduced streamflows and increased atmospheric heating. Previous reports document that one Sierra stream site generally gains groundwater during low flows, while the second Sierra stream site may lose water during low flows. For August the diurnal streamflow variation was 11% at the gaining stream site and 30% at the losing stream site. On the basis of measured diurnal stream temperature variations, streambed infiltration rates were predicted to vary diurnally as much as 20% at the losing stream site. Analysis of results suggests that evapotranspiration losses determined diurnal streamflow variations in the gaining reaches, while in the losing reaches, evapotranspiration losses were compounded by diurnal variations in streambed infiltration. Diurnal variations in stream temperature were reduced in the gaining reaches as a result of discharging groundwater of relatively constant temperature. For the Sierra sites, comparison of results with those from a small tributary demonstrated that stream temperature patterns were useful in delineating discharges of bank storage following

  7. Sahara Dust Cloud

    Science.gov (United States)

    2005-01-01

    [figure removed for brevity, see original site] Dust Particles Click on the image for Quicktime movie from 7/15-7/24 A continent-sized cloud of hot air and dust originating from the Sahara Desert crossed the Atlantic Ocean and headed towards Florida and the Caribbean. A Saharan Air Layer, or SAL, forms when dry air and dust rise from Africa's west coast and ride the trade winds above the Atlantic Ocean. These dust clouds are not uncommon, especially during the months of July and August. They start when weather patterns called tropical waves pick up dust from the desert in North Africa, carry it a couple of miles into the atmosphere and drift westward. In a sequence of images created by data acquired by the Earth-orbiting Atmospheric Infrared Sounder ranging from July 15 through July 24, we see the distribution of the cloud in the atmosphere as it swirls off of Africa and heads across the ocean to the west. Using the unique silicate spectral signatures of dust in the thermal infrared, AIRS can detect the presence of dust in the atmosphere day or night. This detection works best if there are no clouds present on top of the dust; when clouds are present, they can interfere with the signal, making it much harder to detect dust as in the case of July 24, 2005. In the Quicktime movie, the scale at the bottom of the images shows +1 for dust definitely detected, and ranges down to -1 for no dust detected. The plots are averaged over a number of AIRS observations falling within grid boxes, and so it is possible to obtain fractional numbers. [figure removed for brevity, see original site] Total Water Vapor in the Atmosphere Around the Dust Cloud Click on the image for Quicktime movie The dust cloud is contained within a dry adiabatic layer which originates over the Sahara Desert. This Saharan Air Layer (SAL) advances Westward over the Atlantic Ocean, overriding the cool, moist air nearer the surface. This burst of very dry air is visible in the AIRS retrieved total water

  8. ATLAS Live: Collaborative Information Streams

    CERN Document Server

    Goldfarb, S; The ATLAS collaboration

    2010-01-01

    I report on a pilot project launched in 2010 focusing on facilitating communication and information exchange within the ATLAS Collaboration, through the combination of digital signage software and webcasting. The project, called ATLAS Live, implements video streams of information, ranging from detailed detector and data status to educational and outreach material. The content, including text, images, video and audio, is collected, visualised and scheduled using the SCALA digital signage software system. The system is robust and flexible, allowing for the usage of scripts to input data from remote sources, such as the CERN Document Server, Indico, or any available URL, and to integrate these sources into professional-quality streams, including text scrolling, transition effects, inter and intrascreen divisibility. The video is made available to the collaboration or public through the encoding and webcasting of standard video streams, viewable on all common platforms, using a web browser or other common video t...

  9. Documenting DNA in the dust.

    Science.gov (United States)

    Gilbert, M T P

    2017-02-01

    I bought a robotic vacuum cleaner this summer and set it to work. Although my initial expectations were not high, my robot (christened Buddy) finished its cleaning cycle, and then insistently demanded that I empty its dust collection box. As I took the box out, my jaw dropped. I live in a modern house, we don't have pets, and I like to think that I keep it reasonably dust free. But, there was much dust in that box. And when I ran it again 2 days later, the same thing happened. And indeed, every 2 days, Buddy dutifully goes to work, and sucks up a similarly impressive quantity. It's remarkable, and naturally begs the question of where it all comes from? Some is externally derived, entering the house with us or through open windows. Some is clearly fibres shed from clothes, furniture etc. Then there's the skin cells and hair we shed. But at least part is derived from the host of smaller organisms that live in and around our homes, many of which are arthropods (Butte & Heinzow ). I suspect almost all readers are aware that some smaller animals live in our houses - even those who live in the modern urban houses will have occasionally encountered the odd drosophila, silverfish or spider. But I suspect that prior to reading Madden et al.'s article in this issue of Molecular Ecology (Madden et al. ), few of you will have appreciated the true diversity, which, it turns out, is huge. © 2017 John Wiley & Sons Ltd.

  10. Interplanetary and Interstellar Dust Observed by the Wind/WAVES Electric Field Instrument

    Science.gov (United States)

    Malaspina, David; Horanyi, M.; Zaslavsky, A.; Goetz, K.; Wilson, L. B., III; Kersten, K.

    2014-01-01

    Observations of hypervelocity dust particles impacting the Wind spacecraft are reported here for the first time using data from the WindWAVES electric field instrument. A unique combination of rotating spacecraft, amplitude-triggered high-cadence waveform collection, and electric field antenna configuration allow the first direct determination of dust impact direction by any spacecraft using electric field data. Dust flux and impact direction data indicate that the observed dust is approximately micron-sized with both interplanetary and interstellar populations. Nanometer radius dust is not detected by Wind during times when nanometer dust is observed on the STEREO spacecraft and both spacecraft are in close proximity. Determined impact directions suggest that interplanetary dust detected by electric field instruments at 1 AU is dominated by particles on bound trajectories crossing Earths orbit, rather than dust with hyperbolic orbits.

  11. Mineral phases and metals in baghouse dust from secondary ...

    Science.gov (United States)

    Baghouse dust (BHD) is a solid waste generated by air pollution control systems during secondary aluminum processing (SAP). Management and disposal of BHD can be challenging in the U.S. and elsewhere. In this study, the mineral phases, metal content and metal leachability of 78 BHD samples collected from 13 different SAP facilities across the U.S. were investigated. The XRD semi-quantitative analysis of BHD samples suggests the presence of metallic aluminum, aluminum oxide, aluminum nitride and its oxides, spinel, elpasolite as well as diaspora. BHD also contains halite, sylvite and fluorite, which are used as fluxes in SAP activities. Total aluminum (Al) in the BHD samples averaged 18% by weight. Elevated concentrations of trace metals (>100 µgL-1 As; >1000 µgL-1 Cu, Mn, Se, Pb, Mn and Zn) were also detected in the leachate. The U.S. toxicity characteristic leaching procedure (TCLP) results showed that some samples leached above the toxicity limit for Cd, Pb and Se. Exceeding the TCLP limits in all sample is independent of facilities generating the BHD. From the metal content perspective only, it appears that BHD has a higher potential to exhibit toxicity characteristics than salt cake (the largest waste stream generated by SAP facilities). The objective of this study was to investigate BHD from SAP facilities in the U.S. by determining the mineral phases and the metal (Al, As, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Pb, Se and Zn) content of the sample

  12. Time-Based Data Streams: Fundamental Concepts for a Data Resource for Streams

    Energy Technology Data Exchange (ETDEWEB)

    Beth A. Plale

    2009-10-10

    Real time data, which we call data streams, are readings from instruments, environmental, bodily or building sensors that are generated at regular intervals and often, due to their volume, need to be processed in real time. Often a single pass is all that can be made on the data, and a decision to discard or keep the instance is made on the spot. Too, the stream is for all practical purposes indefinite, so decisions must be made on incomplete knowledge. This notion of data streams has a different set of issues from a file, for instance, that is byte streamed to a reader. The file is finite, so the byte stream is becomes a processing convenience more than a fundamentally different kind of data. Through the duration of the project we examined three aspects of streaming data: the first, techniques to handle streaming data in a distributed system organized as a collection of web services, the second, the notion of the dashboard and real time controllable analysis constructs in the context of the Fermi Tevatron Beam Position Monitor, and third and finally, we examined provenance collection of stream processing such as might occur as raw observational data flows from the source and undergoes correction, cleaning, and quality control. The impact of this work is severalfold. We were one of the first to advocate that streams had little value unless aggregated, and that notion is now gaining general acceptance. We were one of the first groups to grapple with the notion of provenance of stream data also.

  13. Analytical Study of Nonlinear Dust Acoustic Waves in Two-Dimensional Dust Plasma with Dust Charge Variation

    International Nuclear Information System (INIS)

    Lin Chang; Zhang Xiulian

    2005-01-01

    The nonlinear dust acoustic waves in two-dimensional dust plasma with dust charge variation is analytically investigated by using the formally variable separation approach. New analytical solutions for the governing equation of this system have been obtained for dust acoustic waves in a dust plasma for the first time. We derive exact analytical expressions for the general case of the nonlinear dust acoustic waves in two-dimensional dust plasma with dust charge variation.

  14. Dust in planetary nebulae

    International Nuclear Information System (INIS)

    Kwok, S.

    1980-01-01

    A two-component dust model is suggested to explain the infrared emission from planetary nebulae. A cold dust component located in the extensive remnant of the red-giant envelope exterior to the visible nebula is responsible for the far-infrared emission. A ward dust component, which is condensed after the formation of the planetary nebula and confined within the ionized gas shell, emits most of the near- and mid-infrared radiation. The observations of NGC 7027 are shown to be consisten with such a model. The correlation of silicate emission in several planetary nebulae with an approximately +1 spectral index at low radio frequencies suggests that both the silicate and radio emissions originate from the remnant of the circumstellar envelope of th precursor star and are observable only while the planetary nebula is young. It is argued that oxygen-rich stars as well as carbon-rich stars can be progenitors of planetary nebulae

  15. Using an Instrumented Drone to Probe Dust Devils on Oregon’s Alvord Desert

    Directory of Open Access Journals (Sweden)

    Brian Jackson

    2018-01-01

    Full Text Available Dust devils are low-pressure, small (many to tens of meters convective vortices powered by surface heating and rendered visible by lofted dust. Dust devils occur ubiquitously on Mars, where they may dominate the supply of atmospheric dust, and since dust contributes significantly to Mars’ atmospheric heat budget, dust devils probably play an important role in its climate. The dust-lifting capacity of a devil likely depends sensitively on its structure, particularly the wind and pressure profiles, but the exact dependencies are poorly constrained. Thus, the exact contribution to Mars’ atmosphere remains unresolved. Analog studies of terrestrial devils have provided some insights into dust devil dynamics and properties but have been limited to near-surface (few meters or relatively high altitude (hundreds of meters sampling. Automated aerial vehicles or drones, combined with miniature, digital instrumentation, promise a novel and uniquely powerful platform from which to sample dust devils at a wide variety of altitudes. In this article, we describe a pilot study using an instrumented quadcopter on an active field site in southeastern Oregon, which (to our knowledge has not previously been surveyed for dust devils. We present preliminary results from the encounters, including stereo image analysis and encounter footage collected onboard the drone. In spite of some technical difficulties, we show that a quadcopter can successfully navigate in an active dust devil, while collecting time-series data about the dust devil’s structure.

  16. Multi-laboratory testing of a screening method for world trade center (WTC) collapse dust.

    Science.gov (United States)

    Rosati, Jacky A; Bern, Amy M; Willis, Robert D; Blanchard, Fredrick T; Conner, Teri L; Kahn, Henry D; Friedman, David

    2008-02-15

    The September 11, 2001 attack on the World Trade Center (WTC) covered a large area of downtown New York City with dust and debris. This paper describes the testing of an analytical method designed to evaluate whether sampled dust contains dust that may have originated from the collapse of the WTC. Using dust samples collected from locations affected and not affected (referred to as 'background' locations) by the collapse, a scanning electron microscopy (SEM) analysis method was developed to screen for three materials that are believed to be present in large quantities in WTC dusts: slag wool, concrete, and gypsum. An inter-laboratory evaluation of the method was implemented by having eight laboratories analyze a number of 'blind' dust samples, consisting of confirmed background dust and confirmed background dust spiked with varying amounts of dust affected by the WTC collapse. The levels of gypsum and concrete in the spiked samples were indistinguishable from the levels in the background samples. Measurements of slag wool in dust demonstrated potential for distinguishing between spiked and background samples in spite of considerable within and between laboratory variability. Slag wool measurements appear to be sufficiently sensitive to distinguish dust spiked with 5% WTC-affected dust from 22 out of 25 background dust samples. Additional development work and inter-laboratory testing of the slag wool component will be necessary to improve the precision and accuracy of the method and reduce inter- and intra-laboratory variability from levels observed in the inter-laboratory evaluation.

  17. Multi-laboratory testing of a screening method for world trade center (WTC) collapse dust

    International Nuclear Information System (INIS)

    Rosati, Jacky A.; Bern, Amy M.; Willis, Robert D.; Blanchard, Fredrick T.; Conner, Teri L.; Kahn, Henry D.; Friedman, David

    2008-01-01

    The September 11, 2001 attack on the World Trade Center (WTC) covered a large area of downtown New York City with dust and debris. This paper describes the testing of an analytical method designed to evaluate whether sampled dust contains dust that may have originated from the collapse of the WTC. Using dust samples collected from locations affected and not affected (referred to as 'background' locations) by the collapse, a scanning electron microscopy (SEM) analysis method was developed to screen for three materials that are believed to be present in large quantities in WTC dusts: slag wool, concrete, and gypsum. An inter-laboratory evaluation of the method was implemented by having eight laboratories analyze a number of 'blind' dust samples, consisting of confirmed background dust and confirmed background dust spiked with varying amounts of dust affected by the WTC collapse. The levels of gypsum and concrete in the spiked samples were indistinguishable from the levels in the background samples. Measurements of slag wool in dust demonstrated potential for distinguishing between spiked and background samples in spite of considerable within and between laboratory variability. Slag wool measurements appear to be sufficiently sensitive to distinguish dust spiked with 5% WTC-affected dust from 22 out of 25 background dust samples. Additional development work and inter-laboratory testing of the slag wool component will be necessary to improve the precision and accuracy of the method and reduce inter- and intra-laboratory variability from levels observed in the inter-laboratory evaluation

  18. Measurements of fibrogenous dusts using the VC 25

    International Nuclear Information System (INIS)

    Coenen, W.

    1975-01-01

    For routine measurements and assessments of fibrogenous dusts the Dust Research Institute (Staubforschungsinstitut), together with the technical supervisory services of the social insurances for trade, has, since 1973, been using a new measuring system. It consists of the sampling device VC 25 (which can be used selectively for the determination of respirable dust or of total dust), of an evaluation instrument based on the β-ray absorption principle ( 147 Pm), and of a filter holder for sampling, transporting, and evaluating. This system makes it possible to carry out a decentralized sampling and a centralized evaluation, including the analysis of noxious substances and the collection of data. At the present, one evaluation station can attend to 50 sampling devices. In 1975, a total number of 3,500 dust measurements will be evaluated. Practical experience, limits of application, and possibilities of improvement are reported, as are the results of comparative tests by other methods. (orig.) [de

  19. Dust-Plasma Interactions

    International Nuclear Information System (INIS)

    Rosenberg, M.

    2010-01-01

    The objective of our theoretical research under this grant over the past 3 years was to develop new understanding in a range of topics in the physics of dust-plasma interactions, with application to space and the laboratory. We conducted studies related to the physical properties of dust, waves and instabilities in both weakly coupled and strongly coupled dusty plasmas, and innovative possible applications. A major consideration in our choice of topics was to compare theory with experiments or observations, and to motivate new experiments, which we believe is important for developing this relatively new field. Our research is summarized, with reference to our list of journal publications.

  20. Dust processing device for inside of vacuum vessel of thermonuclear reactor

    International Nuclear Information System (INIS)

    Okumura, Atsushi; Tsujimura, Seiichi; Takahashi, Kenji; Ueda, Yasutoshi; Kuwata, Masayasu; Onozuka, Masaki.

    1995-01-01

    The device of the present invention can occasionally recover dusts in a vacuum vessel of a thermonuclear reactor. In addition, fine powdery dusts are never scattered to the vacuum vessel. Namely, a processing device main body comprises a locally sealed space in the vacuum vessel. A blow-up device blows up and floats dusts accumulated in the vacuum vessel to the processing device main body. A discharge plate electrically charges the floating dusts by discharge. An electrode collects the charged dusts. Collected dusts are recovered together with a pressurized gas through a dust recovering port to the outside of the processing device. With such a constitution, it is not necessary to release the vacuum vessel to the atmosphere and evacuate after the completion of the collection of the dusts on every time when the dusts are generated as in the prior art. It is no more necessary for an operator to enter into the vacuum vessel and recover the dusts. Since fine powdery dusts are never scattered in the vacuum vessel, no undesired effects are given to exhaustion facilities and instruments of the vacuum vessel. (I.S.)

  1. Is the Stream Always Bluer on the Other Side?

    Science.gov (United States)

    Jenkins, T.; Chase, Z.

    2017-12-01

    Examining water quality, fish species present, habitat quality, and sources of pollution are important to better understanding the health of a stream. In Florida, the Fish and Wildlife Conservation Commission (FWC) works to monitor the health of its streams, and partnerships with . By collecting, analyzing, and comparing fish abundance data from a couple of streams in Escambia County, Florida, we can help FWC determine how to best support and protect stream habitats and fish-species in our Florida community.

  2. Characterization of airborne float coal dust emitted during continuous mining, longwall mining and belt transport.

    Science.gov (United States)

    Shahan, M R; Seaman, C E; Beck, T W; Colinet, J F; Mischler, S E

    2017-09-01

    Float coal dust is produced by various mining methods, carried by ventilating air and deposited on the floor, roof and ribs of mine airways. If deposited, float dust is re-entrained during a methane explosion. Without sufficient inert rock dust quantities, this float coal dust can propagate an explosion throughout mining entries. Consequently, controlling float coal dust is of critical interest to mining operations. Rock dusting, which is the adding of inert material to airway surfaces, is the main control technique currently used by the coal mining industry to reduce the float coal dust explosion hazard. To assist the industry in reducing this hazard, the Pittsburgh Mining Research Division of the U.S. National Institute for Occupational Safety and Health initiated a project to investigate methods and technologies to reduce float coal dust in underground coal mines through prevention, capture and suppression prior to deposition. Field characterization studies were performed to determine quantitatively the sources, types and amounts of dust produced during various coal mining processes. The operations chosen for study were a continuous miner section, a longwall section and a coal-handling facility. For each of these operations, the primary dust sources were confirmed to be the continuous mining machine, longwall shearer and conveyor belt transfer points, respectively. Respirable and total airborne float dust samples were collected and analyzed for each operation, and the ratio of total airborne float coal dust to respirable dust was calculated. During the continuous mining process, the ratio of total airborne float coal dust to respirable dust ranged from 10.3 to 13.8. The ratios measured on the longwall face were between 18.5 and 21.5. The total airborne float coal dust to respirable dust ratio observed during belt transport ranged between 7.5 and 21.8.

  3. On the injection of fine dust from the Jovian magnetosphere

    Science.gov (United States)

    Maravilla, D.; Flammer, K. R.; Mendis, D. A.

    1995-01-01

    Using a simple aligned dipole model of the Jovian magnetic field, and exploiting integrals of the gravito-electrodynamic equation of motion of charged dust, we obtain an analytic result which characterizes the nature of the orbits of grains of different (fixed) charge-to-mass ratios launched at different velocities from different radial distances from Jupiter. This enables us to consider various possible sources of the dust-streams emanating from Jupiter which have been observed by the Ulysses spacecraft. We conclude that Jupiter's volcanically active satellite Io is the likely source, in agreement with the earlier calculations and simulations of Horanyi et al. using a detailed three-dimensional model of the Jovian magnetosphere. Our estimates of the size range and the velocity range of these dust grains are also in good agreement with those of the above authors and are within the error bars of the observations.

  4. Paleo-dust insights onto dust-climate interactions

    Science.gov (United States)

    Albani, S.; Mahowald, N. M.

    2017-12-01

    Mineral dust emissions are affected by changing climate conditions, and in turn dust impacts the atmospheric radiation budget, clouds and biogeochemical cycles. Climate and public health dust-related issues call for attention on the fate of the dust cycle in the future, and the representation of the dust cycle is now part of the strategy of the Paleoclimate Modelling Intercomparison Project phase 4 and the Coupled Model Intercomparison Project phase 6 (PMIP4-CMIP6). Since mineral aerosols are one of the most important natural aerosols, understanding past dust responses to climate in the paleoclimate will allow us to better understand mineral aerosol feedbacks with climate and biogeochemistry in the Anthropocene. Modern observations and paleoclimate records offer the possibility of multiple, complementary views on the global dust cycle, and allow to validate and/or constrain the numerical representation of dust in climate and Earth system models. We present our results from a set of simulations with the Community Earth System Model for different climate states, including present and past climates such as the pre-industrial, the mid-Holocene and the Last Glacial Maximum. A set of simulations including a prognostic dust cycle was thoroughly compared with a wide set of present day observations from different platforms and regions, in order to realistically constrain the magnitude of dust load, surface concentration, deposition, optical properties, and particle size distributions. The magnitude of emissions for past climate regimes was constrained based on compilations of paleodust mass accumulation rates and size distributions, as well as based on information on dust provenance. The comparison with a parallel set of simulations without dust allows estimating the impacts of dust on surface climate. We analyze impacts of dust on the mean and variability of surface temperature and precipitation in each climate state, as well as the impacts that changing dust emissions had

  5. Heavy Metals in Street Dust in Sarajevo Area, Bosnia and Herzegovina

    OpenAIRE

    A. Razanica; J. Huremovic; S. Zero; S. Gojak-Salimovic; M. Memic

    2014-01-01

    Heavy metal pollutant in urban street dust has become a growing concern in recent years. Street dust samples from urban and suburban areas were collected from the Sarajevo area, Bosnia and Herzegovina, during the spring season of 2013. Samples were collected from low and high density traffic roads, industrial zones, parks, parking places, hospitals and local health centres, school gardens. The levels of heavy metals of street dusts were determined by flame atomic absorption spectrometry (FAAS...

  6. 75 FR 32142 - Combustible Dust

    Science.gov (United States)

    2010-06-07

    ... Combustible Dust AGENCY: Occupational Safety and Health Administration (OSHA), Labor. ACTION: Notice of combustible dust Web Chat. SUMMARY: OSHA invites interested parties to participate in a Web Chat on the workplace hazards of combustible dust. OSHA plans to use the information gathered in response to this Web...

  7. Prioritized Contact Transport Stream

    Science.gov (United States)

    Hunt, Walter Lee, Jr. (Inventor)

    2015-01-01

    A detection process, contact recognition process, classification process, and identification process are applied to raw sensor data to produce an identified contact record set containing one or more identified contact records. A prioritization process is applied to the identified contact record set to assign a contact priority to each contact record in the identified contact record set. Data are removed from the contact records in the identified contact record set based on the contact priorities assigned to those contact records. A first contact stream is produced from the resulting contact records. The first contact stream is streamed in a contact transport stream. The contact transport stream may include and stream additional contact streams. The contact transport stream may be varied dynamically over time based on parameters such as available bandwidth, contact priority, presence/absence of contacts, system state, and configuration parameters.

  8. Stream corridor management

    Science.gov (United States)

    Richard E. Wehnes

    1989-01-01

    The quality of streams and stream habitat for aquatic life and terrestrial animals in the central hardwood forest can be maintained or enhanced through careful protection, management, and re-establishment of streamside forests.

  9. StreamCat

    Data.gov (United States)

    U.S. Environmental Protection Agency — The StreamCat Dataset provides summaries of natural and anthropogenic landscape features for ~2.65 million streams, and their associated catchments, within the...

  10. Identification of the exploatation dust in road dust

    Directory of Open Access Journals (Sweden)

    B. Gajdzik

    2012-01-01

    Full Text Available The aim of this publication is to determine models of explore dust from vehicle brake systems and the presentationof measurement results of the exploitation dust, which is separate from road dust. The following methods and measuring devices were used: T-01M device, screen analysis, analysis of chemical composition with the use of a scanning microscope with Energy Dispersive x-ray Spectroscopy (EDS analyser. The measurements for identifying this type of dust were conducted on marked sections of roads: motorway, city road and mountain road. The explored dust was distinguished in the following car systems: brakes, clutch plates, tyres and catalytic converters.

  11. 75 FR 64411 - Lowering Miners' Exposure to Respirable Coal Mine Dust, Including Continuous Personal Dust Monitors

    Science.gov (United States)

    2010-10-19

    ... proposed rule is an important element in MSHA's Comprehensive Initiative to ``End Black Lung--Act Now..., and chronic bronchitis, known collectively as ``black lung.'' These diseases are debilitating... reducing the respirable coal mine dust levels, miners continue to develop black lung. Based on recent data...

  12. Salt Efflorescence Effects on Soil Surface Erodibility and Dust Emissions

    Science.gov (United States)

    Van Pelt, R. S.; Zhang, G.

    2017-12-01

    Soluble salts resulting from weathering of geological materials often form surface crusts or efflorescences in areas with shallow saline groundwater. In many cases, the affected areas are susceptible to wind erosion due to their lack of protective vegetation and their flat topography. Fugitive dusts containing soluble salts affect the biogeochemistry of deposition regions and may result in respiratory irritation during transport. We created efflorescent crusts on soil trays by surface evaporation of single salt solutions and bombarded the resultant efflorescences with quartz abrader sand in a laboratory wind tunnel. Four replicate trays containing a Torrifluvent soil affected by one of nine salts commonly found in arid and semiarid streams were tested and the emissions were captured by an aspirated multi-stage deposition and filtering system. We found that in most cases the efflorescent crust reduced the soil surface erodibility but also resulted in the emission of salt rich dust. Two of the salts, sodium thiosulfate and calcium chloride, resulted in increased soil volume and erodibility. However, one of the calcium chloride replicates was tested after an outbreak of humid air caused hygroscopic wetting of the soil and it became indurated upon drying greatly decreasing the erodibility. Although saline affected soils are not used for agricultural production and degradation is not a great concern, the release of salt rich dust is an area of environmental concern and steps to control the dust emissions from affected soils should be developed. Future testing will utilize suites of salts found in streams of arid and semiarid regions.

  13. Transport asymmetry and release mechanisms of metal dust in the reversed-field pinch configuration

    International Nuclear Information System (INIS)

    Bykov, I; Bergsåker, H; Frassinetti, L; Brunsell, P R; Vignitchouk, L; Ratynskaia, S; Banon, J-P; Tolias, P

    2014-01-01

    Experimental data on dust resident in the EXTRAP T2R reversed-field pinch are reported. Mobile dust grains are captured in situ by silicon collectors, whereas immobile grains are sampled post mortem from the wall by adhesive tape. The simulation of collection asymmetries by the MIGRAINe dust dynamics code in combination with the experimental results is employed to deduce some characteristics of the mechanism of intrinsic dust release. All evidence suggests that re-mobilization is dominant with respect to dust production. (paper)

  14. Acute effect of glucan-spiked office dust on nasal and pulmonary inflammation in guinea pigs

    DEFF Research Database (Denmark)

    Straszek, Sune; Adamcakova-Dodd, Andrea; Nervana, Metwali

    2007-01-01

     office dust and glucan on nasal and pulmonary inflammation. This is relevant for humans with occupational exposure in waste handling and farming and buildings with mold problems.  Office dust collected from Danish offices was spiked with 1% (1-3)-β-glucan (curdlan). Guinea pig nasal cavity volume was measured...... office dust exposures produced a delayed nasal sub-acute congestion in guinea pigs compared to office dust alone but extrapolated to nasal congestion in humans, paralleling the nasal congestion seen in human volunteers exposed to the same dust, it may not have clinical importance....

  15. Dust pollution from agriculture

    Science.gov (United States)

    Fine dust particles emitted from agricultural facilities, lands and operations are considered pollutants when they affect public health and welfare. These particles, with a diameter of less than or equal to 2.5 µm (PM2.5) and less than or equal to 10 µm (PM10), are regulated by government agencies. ...

  16. Allergies, asthma, and dust

    Science.gov (United States)

    ... and box springs. House dust may also contain tiny particles of pollen, mold, fibers from clothing and fabrics, and detergents. All of these can also trigger allergies and asthma. Choose the Right Home Furnishings You can do many things to limit ...

  17. Hydrometallurgical process for recovering iron sulfate and zinc sulfate from baghouse dust

    Science.gov (United States)

    Zaromb, Solomon; Lawson, Daniel B.

    1994-01-01

    A process for recovering zinc/rich and iron-rich fractions from the baghouse dust that is generated in various metallurgical operations, especially in steel-making and other iron-making plants, comprises the steps of leaching the dust by hot concentrated sulfuric acid so as to generate dissolved zinc sulfate and a precipitate of iron sulfate, separating the precipitate from the acid by filtration and washing with a volatile liquid, such as methanol or acetone, and collecting the filtered acid and the washings into a filtrate fraction. The volatile liquid may be recovered distillation, and the zinc may be removed from the filtrate by alternative methods, one of which involves addition of a sufficient amount of water to precipitate hydrated zinc sulfate at 10.degree. C., separation of the precipitate from sulfuric acid by filtration, and evaporation of water to regenerate concentrated sulfuric acid. The recovery of iron may also be effected in alternative ways, one of which involves roasting the ferric sulfate to yield ferric oxide and sulfur trioxide, which can be reconverted to concentrated sulfuric acid by hydration. The overall process should not generate any significant waste stream.

  18. Productivity of Stream Definitions

    NARCIS (Netherlands)

    Endrullis, Jörg; Grabmayer, Clemens; Hendriks, Dimitri; Isihara, Ariya; Klop, Jan

    2007-01-01

    We give an algorithm for deciding productivity of a large and natural class of recursive stream definitions. A stream definition is called ‘productive’ if it can be evaluated continuously in such a way that a uniquely determined stream is obtained as the limit. Whereas productivity is undecidable

  19. Productivity of stream definitions

    NARCIS (Netherlands)

    Endrullis, J.; Grabmayer, C.A.; Hendriks, D.; Isihara, A.; Klop, J.W.

    2008-01-01

    We give an algorithm for deciding productivity of a large and natural class of recursive stream definitions. A stream definition is called ‘productive’ if it can be evaluated continually in such a way that a uniquely determined stream in constructor normal form is obtained as the limit. Whereas

  20. Investigation of stream temperature response to non-uniform groundwater discharge in a Danish lowland stream

    DEFF Research Database (Denmark)

    Karthikeyan, Matheswaran; Kastrup Blemmer, Morten; Thorn, P.

    2015-01-01

    Non-uniform groundwater discharge into streams influences temperature, a vital stream physical property recognized for its dominant controls on biological processes in lotic habitats at multiple scales. Understanding such spatially heterogeneous processes and their effects is difficult on the basis...... of stream temperature models often calibrated with discrete temperature measurements. This study focused on examining the effect of groundwater discharge on stream temperature using a physically based stream temperature model calibrated on spatially rich high-resolution temperature measurements....... A distributed temperature sensing (DTS) system with a 1.8-km fibre optic cable was used to collect temperature measurements for every 1m of the reach length at 3-min temporal resolution in the stream Elverdamsåen. The groundwater inflow locations identified using DTS data and 24-h temperature measurements (14...

  1. Multiple scattering wavelength dependent backscattering of kaolin dust in the IR: Measurements and theory

    Science.gov (United States)

    Ben-David, Avishai

    1992-01-01

    Knowing the optical properties of aerosol dust is important for designing electro-optical systems and for modeling the effect on propagation of light in the atmosphere. As CO2 lidar technology becomes more advanced and is used for multiwavelength measurements, information on the wavelength dependent backscattering of aerosol dust particles is required. The volume backscattering coefficient of aerosols in the IR is relatively small. Thus, only a few field measurements of backscattering, usually at only a few wavelengths, are reported in the literature. We present spectral field measurements of backscattering of kaolin dust in the 9-11 micron wavelength range. As the quantity of dust increases, multiple scattering contributes more to the measured backscattered signal. The measurements show the effect of the dust quantity of the spectral backscatter measurements. A simple analytical two stream radiative transfer model is applied to confirm the measurements and to give insight to the multiple scattering spectra of backscattering.

  2. Oceanographic Data collected during the Islands in the Stream Expedition on NOAA Ship Gordon Gunter in the North Atlantic Ocean and the Gulf of Mexico between 2001-05-10 to 2001-10-04 (NCEI Accession 0104416)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Islands in the Stream expedition explored protected and unprotected deep water coral reefs and hard-bottom communities throughout the Gulf of Mexico and South...

  3. A bank-operated traveling-block cableway for stream discharge and sediment measurements

    Science.gov (United States)

    James J. Paradiso

    2000-01-01

    Streams often present a challenge for collecting flow and sediment measurements on a year-round basis. Streams that can normally be waded become hazardous during seasonal flows, either endangering hydrographers or precluding data collection completely. A hand-operated cableway permits the accurate and safe collection of discharge and sediment data from the stream bank...

  4. Characterization of lead, chromium, and cadmium in dust emitted from municipal solid waste incineration plants

    International Nuclear Information System (INIS)

    Shiota, K; Imai, G; Oshita, K; Takaoka, M

    2013-01-01

    The dust is emitted from municipal solid waste incinerators (MSWIs). Volatile toxic heavy metals are abundant in smaller dust particles and influence the toxicity of particulate matter such as fine particles 2.5 ). However, little is known about the properties of these metals in fine dust particles. Therefore, X-ray absorption fine structure (XAFS) spectroscopy was used to investigate the chemical states of lead (Pb), chromium (Cr), and cadmium (Cd) in MSWI dust collected for nine particle size fractions at the inlet of the dust collector and the stacks of two MSWI plants. XAFS spectroscopy of the dust in the inlet of the dust collectors showed that finer dust contained predominantly Pb as PbCl 2 with some PbSiO 3 , coarser dust consisted of Cr forms, including more toxic Cr(VI) species, and all dust contained CdCl 2 . Although the dust collector removed almost all of the Pb, trace amounts of PbCl 2 remained in the stack gas after passing through the dust collector.

  5. Origin-Dependent Variations in the Atmospheric Microbiome in Eastern Mediterranean Dust Storms

    Science.gov (United States)

    Rudich, Y.; Gat, D.

    2017-12-01

    Microorganisms carried by dust storms are transported through the atmosphere and may affect human health and the functionality of microbial communities in various environments. Characterizing the dust-borne microbiome in dust storms of different origins, or that followed different trajectories, provides valuable data to improve our understanding of global health and environmental impacts. We present a comparative study on the diversity of dust- borne bacterial communities in dust storms from three distinct origins—North Africa, Syria and Saudi Arabia—and compare them with local bacterial communities sampled on clear days, all collected at a single location, in Israel. Storms from different dust origins exhibited distinct bacterial communities, with signature bacterial taxa for each source. Dust storms were characterized by a lower abundance of selected antibiotic resistance genes (ARGs) compared with ambient dust, asserting that the origin of these genes is local, possibly anthropogenic. With the progression of the storm, the storm-borne bacterial community showed increasing resemblance to ambient dust, suggesting mixing with local dust. We will also discuss how exposure to dust containing biological components affect lung epithelial cells. These results show, for the first time, that dust storms from different sources display distinct bacterial communities, suggesting possible distinct effects on the environment and public health.

  6. Evolution of meteoroid streams

    International Nuclear Information System (INIS)

    Babadzhanov, P.B.; Obrubov, Yu.V.

    1987-01-01

    A meteoroid stream generally considered to be an elliptical ring of relatively small thickness is described. Such shape is attributable to meteoroid streams in an early stage of their evolution. Differences in planetary perturbations influencing the meteoroid particles ejected from the parent body from various points in its orbit at different velocities and time can result in a significant thickening of the stream. Our studies on the evolution of the short-period meteoroid streams have shown that these streams can produce several couples of showers active in different seasons of the year. (author). 5 figs., 7 tabs., 53 res

  7. Characterization of Aeolian Dust in East China and Japan from 2001 to 2003(ADEC-Aeolian Dust Experiment on Climate Impact-)

    OpenAIRE

    Yutaka, KANAI; Atsuyuki, OHTA; Hikari, KAMIOKA; Shigeru, TERASHIMA; Noboru, IMAI; Michiyo, KANAI; Hiroshi, SHIMIZU; Yoshio, TAKAHASHI; Kenji, KAI; Masahiko, HAYASHI; Renjian, ZHANG; Lifang, SHENG; Geological Survey of Japan (GSJ), National Institute of Advanced Industrial Science and Technology (AIST); Geological Survey of Japan (GSJ), National Institute of Advanced Industrial Science and Technology (AIST); Geological Survey of Japan (GSJ), National Institute of Advanced Industrial Science and Technology (AIST)

    2005-01-01

    In order to elucidate the variation and characterization of dust particles that originate in the arid and semi-arid regions of inland Asia and are transported to Japan, we established a sampling network system in east China and Japan and collected aeolian dust under the Japan-China joint project "ADEC". Monitoring of the total suspended particle (TSP) and size-segregated dust concentrations were carried out in Beijing, Qingdao and Hefei in China, and Fukuoka, Nagoya, Tsukuba and Naha in Japan...

  8. Mechanisms of metal dusting corrosion

    DEFF Research Database (Denmark)

    Hummelshøj, Thomas Strabo

    In this thesis the early stages of metal dusting corrosion is addressed; the development of carbon expanded austenite, C, and the decomposition hereof into carbides. Later stages of metal dusting corrosion are explored by a systematic study of stainless steel foils exposed to metal dusting...... the supersaturated alloy, into a diverse carbide network. Finally, the foils turn into metal dust accompanied by a thinning and disappearance of the foils. Investigations of TEM samples, prepared by means of FIB, on the carbide network revealed a lamellar structure with carbides and austenite. Finally, the mutual...... influence of oxygen and carbon on the metal dusting corrosion is explored. The results indicate that exposure to metal dusting conditions have a detrimental effect on the resistance against oxidation and, conversely, that exposure to oxidation has a detrimental effect on the resistance towards metal dusting...

  9. The dust-acoustic mode in two-temperature electron plasmas with ...

    Indian Academy of Sciences (India)

    as the collection of background plasma electrons and ions by dust grains, photoelectron emission, secondary .... where qd is the mean charges of the dust grains and Ij is the collection current of jth species (j = ec, eh, ..... hot electron components on the dusty grains, as it is more mobile when compared to cold electrons and ...

  10. Sensitization to house dust mites in Reykjavik, Iceland, in the absence of domestic exposure to mites.

    Science.gov (United States)

    Hallas, T E; Gislason, D; Björnsdottir, U S; Jörundsdottir, K B; Janson, C; Luczynska, C M; Gislason, T

    2004-05-01

    House dust mites are common sources of indoor allergens. In Reykjavik, Iceland, 9% of the young adult population had serum-specific IgE to Dermatophagoides pteronyssinus. Sensitization to mites is usually assumed to be due to exposure to house dust mites in the indoor environment. This investigation was carried out to measure the concentrations of house dust mite allergens and to investigate which species of mites were present in beds in Iceland. A total of 197 randomly selected adults were visited at home using the European Community Respiratory Health Survey (ECRHS) II Indoor protocol. Dust samples were collected from mattresses for measurement of house dust mite allergen concentrations and to estimate the number and type of house dust mites. Additional samples from mattresses and floors were collected from the homes of 10 patients with positive skin prick tests (SPT) to D. pteronyssinus. House dust mite allergen concentrations were measured using ELISA and examination of mite species was carried out using microscopy. Climatic parameters were assessed using psychrometer readings in the bedrooms and outdoors. We found two single mite specimens, both D. pteronyssinus, in two dust samples. Mite allergen analyses indicated that two other dust samples had Der f 1 results close to the cut-off of 0.1 microg/g of dust. No samples were positive for Der p 1. In an additional collection of dust from the homes of 10 SPT-positive patients no Dermatophagoides spp. were found. Reykjavik citizens are exposed to extremely low amounts of house dust mite allergens in their homes. Possible alternative sources for sensitization are discussed, such as bird nests, exposure from travelling abroad, or other mites or invertebrates that cross-react with house dust mite allergens. Our findings suggest that exposures other than to house dust mites indoors are possible sources of mite allergen exposure.

  11. Road Dust Emission Sources and Assessment of Street Washing Effect

    OpenAIRE

    Karanasiou, Angeliki; Amato, Fulvio; Moreno, Teresa; Lumbreras Martin, Julio; Borge García, Rafael; Linares, Cristina; Boldo, E.; Alastuey, Andres; Querol, Xavier

    2014-01-01

    Although previous studies report on the effect of street washing on ambient particulate matter levels, there is a lack of studies investigating the results of street washing on the emission strength of road dust. A sampling campaign was conducted in Madrid urban area during July 2009 where road dust samples were collected in two sites, namely Reference site (where the road surface was not washed) and Pelayo site (where street washing was performed daily during night). Following the chemical c...

  12. Heavy Metals Speciation in Dust Samples from Various Parts of ...

    African Journals Online (AJOL)

    Dust samples were collected using 1m2 HDPE containers, oven dried at 70OC and sieved through 100ìm nylon sieve. 1g of each sample was digested using HCl/HNO3/H2O2 acid mixture and the concentration levels of 8 selected metals were measured using ICP-MS. Average concentrations of heavy metals in dust ...

  13. 76 FR 61752 - Cotton Dust Standard; Extension of the Office of Management and Budget's (OMB) Approval of...

    Science.gov (United States)

    2011-10-05

    ... Occupational Safety and Health Administration Cotton Dust Standard; Extension of the Office of Management and... the information collection requirements specified in the Cotton Dust Standard (29 CFR 1910.1043... requirements specified in the Cotton Dust Standard protect workers from the adverse health effects that may...

  14. Dust Growth in Astrophysical Plasmas

    Science.gov (United States)

    Bingham, R.; Tsytovich, V. N.

    2002-12-01

    Dust formation in space is important in diverse environments such as dust molecular clouds, proto-planetary nebulae, stellar outbursts, and supernova explosions. The formation of dust proceeds the formation of stellar objects and planets. In all these environments the dust particles interact with both neutral and plasma particles as well as with (ultraviolet) radiation and cosmic rays. The conventional view of grain growth is one based on accretion by the Van der Waals and chemical forces [Watson and Salpeter [14] considered in detail both theoretically and numerically (Kempf at all [6],Meaking [7]( and confirmed recently by micro-gravity experiments Blum et all [2]). The usual point of view is that the dust grow is occurring in dust molecular clouds at very low temperatures ~ (10 - 30)° K and is a slow process - dust grows to a size of about 0.1 μm in 106 - 109 years. This contradicts recent observations of dust growing in winds of C-stars in about 10 years and behind the supernova SN1987A shock in about 500 days. Also recent observation of star formation at the edge of irradiated dust clouds suggests that new plasma mechanism operates in star formation. Dusty plasma mechanisms of agglomeration are analyzed as an explanation of the new astrophysical observation. New micro-gravity experiments are proposed for observing the plasma mechanisms of dust agglomeration at gas pressures substantially higher than used in ([2]. Calculations for the growth rates of dust agglomeration due to plasma mechanisms are presented. It is shown that at large neutral gas densities the dust plasma attraction provides an explanation of dust grow in about 10 days observed in H-star winds. Ionization by cosmic rays and by radioactive dust can provide the dust attraction necessary for forming dust clumping observed in molecular clouds and the fractal plasma clumping can enhance the time to reach the gravitational contraction phase operating at the final stage of star formation. A new

  15. Using an Instrumented Drone to Sample Dust Devils

    Science.gov (United States)

    Jackson, Brian; Lorenz, Ralph; Davis, Karan; Lipple, Brock

    2017-10-01

    Dust devils are low-pressure, small (many to tens of meters) convective vortices powered by surface heating and rendered visible by lofted dust. Dust devils occur in arid climates on Earth, where they degrade air quality and pose a hazard to small aircraft. They also occur ubiquitously on Mars, where they may dominate the supply of atmospheric dust. Since dust contributes significantly to Mars’ atmospheric heat budget, dust devils probably play an important role in its climate. The dust-lifting capacity of a devil likely depends sensitively on its structure, particularly the wind and pressure profiles, but the exact dependencies are poorly constrained. Thus, the exact contribution to Mars’ atmosphere remains unresolved. Moreover, most previous studies of martian dust devils have relied on passive sampling of the profiles via meteorology packages on landed spacecraft, resulting in random encounter geometries which non-trivially skew the retrieved profiles. Analog studies of terrestrial devils have employed more active sampling (instrumented vehicles or manned aircraft) but have been limited to near-surface (few meters) or relatively high altitude (hundreds of meters) sampling. Unmanned aerial vehicles (UAVs) or drones, combined with miniature, digital instrumentation, promise a novel and uniquely powerful platform from which to sample dust devils via (relatively) controlled geometries at a wide variety of altitudes. In this presentation, we will describe a pilot study using an instrumented quadcopter on an active field site in southeastern Oregon, which (to our knowledge) has not previously been surveyed for dust devils. We will present preliminary results from the resulting encounters, including stereo image analysis and encounter footage collected onboard the drone.

  16. Lead isotopes and trace metals in dust at Yucca Mountain

    Science.gov (United States)

    Kwak, Loretta; Neymark, Leonid A.; Peterman, Zell E.

    2008-01-01

    Lead (Pb)-isotope compositions and trace-metal concentrations were determined for samples of dust collected from underground and surface locations at and near the proposed radioactive waste repository at Yucca Mountain, Nevada. Rare earth element concentrations in the dust samples from the underground tunnels are similar to those in wholerock samples of the repository host rocks (Miocene Tiva Canyon Tuff and Topopah Spring Tuff), supporting interpretation that the subsurface dust is mainly composed of rock comminuted during tunnel construction. Other trace metals (arsenic, cadmium, cobalt, chromium, copper, manganese, nickel, lead, antimony, thallium, and zinc) are variably enriched in the subsurface dust samples relative to the average concentrations in the host rocks. Average concentrations of arsenic and lead in dust samples, high concentrations of which can cause corrosion of waste canisters, have enrichment factors from 1.2 to 1.6 and are insignificant relative to the range of concentrations for these metals observed in the host rock samples. Most dust samples from surface sites also are enriched in many of these trace metals relative to average repository host rocks. At least some of these enrichments may be artifacts of sampling. Plotted on a 208Pb/206Pb-207Pb/206Pb graph, Pb-isotope compositions of dust samples from underground sites form a mixing line extending from host-rock Pb-isotope compositions towards compositions of many of the dust samples from surface sites; however, combined Pb concentration and isotope data indicate the presence of a Pbenriched component in the subsurface dust that is not derived from host rock or surface dust and may derive from anthropogenic materials introduced into the underground environment.

  17. Distribution of dust during two dust storms in Iceland

    Science.gov (United States)

    Ösp Magnúsdóttir, Agnes; Dagsson-Waldhauserova, Pavla; Arnalds, Ólafur; Ólafsson, Haraldur

    2017-04-01

    Particulate matter mass concentrations and size fractions of PM1, PM2.5, PM4, PM10, and PM15 measured in transversal horizontal profile of two dust storms in southwestern Iceland are presented. Images from a camera network were used to estimate the visibility and spatial extent of measured dust events. Numerical simulations were used to calculate the total dust flux from the sources as 180,000 and 280,000 tons for each storm. The mean PM15 concentrations inside of the dust plumes varied from 10 to 1600 ?g?m?3 (PM10 = 7 to 583 ?g?m?3). The mean PM1 concentrations were 97-241 ?g?m?3 with a maximum of 261 ?g?m?3 for the first storm. The PM1/PM2.5 ratios of >0.9 and PM1/PM10 ratios of 0.34-0.63 show that suspension of volcanic materials in Iceland causes air pollution with extremely high PM1 concentrations, similar to polluted urban areas in Europe or Asia. Icelandic volcanic dust consists of a higher proportion of submicron particles compared to crustal dust. Both dust storms occurred in relatively densely inhabited areas of Iceland. First results on size partitioning of Icelandic dust presented here should challenge health authorities to enhance research in relation to dust and shows the need for public dust warning systems.

  18. Determination of road dust loadings and chemical characteristics using resuspension.

    Science.gov (United States)

    Chen, Jianhua; Wang, Wei; Liu, Hongjie; Ren, Lihong

    2012-03-01

    The contribution of fugitive dust from traffic to air pollution can no longer be ignored in China. In order to obtain the road dust loadings and to understand the chemical characteristics of PM(10) and PM(2.5) from typical road dust, different paved roads in eight districts of Beijing were selected for dust collection during the four seasons of 2005. Ninety-eight samples from 28 roads were obtained. The samples were resuspended using equipment assembled to simulate the rising process of road dust caused by the wind or wheels in order to obtain the PM(10) and PM(2.5) filter samples. The average road dust loading was 3.82 g m(-2), with the highest of 24.22 g m(-2) being in Hutongs in the rural-urban continuum during winter. The road dust loadings on higher-grade roads were lower than those on lower-grade roads. Attention should be paid to the pollution in the rural-urban continuum areas. The sums of element abundances measured were 16.17% and 18.50% for PM(10) and PM(2.5) in road dust. The average abundances of OC and EC in PM(10) and PM(2.5) in road dust were 11.52%, 2.01% and 12.50%, 2.06%, respectively. The abundance of elements, water-soluble ions, and OC, EC in PM(10) and PM(2.5) resuspended from road dust did not change greatly with seasons and road types. The soil dust, construction dust, dust emitted from burning coal, vehicle exhaust, and deposition of particles in the air were the main sources of road dust in Beijing. Affected by the application of snow-melting agents in Beijing during winter, the amount of Cl( - ) and Na( + ) was much higher during that time than in the other seasons. This will have a certain influence on roads, bridges, vegetations, and groundwater.

  19. Continuous measurement of number concentrations and elemental composition of aerosol particles for a dust storm event in Beijing

    Science.gov (United States)

    Zhang, Renjian; Han, Zhiwei; Shen, Zhenxing; Cao, Junji

    2008-01-01

    A continuous measurement of number size distributions and chemical composition of aerosol particles was conducted in Beijing in a dust storm event during 21-26 March 2001. The number concentration of coarse particles (>2 μm) increased more significantly than fine particles (dust storm due to dust weather, while the anthropogenic aerosols collected during the non-dust-storm period tended to be associated with fine particles. Elemental compositions were analyzed by using proton-induced X-ray emission (PIXE). The results show that 20 elements in the dust storm were much higher than in the non-dust-storm period. The calculated soil dust concentration during the dust storm was, on average, 251.8 μg m-3, while it was only 52.1 μg m-3 on non-dust-storm days. The enrichment factors for Mg, Al, P, K, Ca, Ti, Mn, Fe, Cl, Cu, Pb, and Zn show small variations between the dust storm and the non-dust-storm period, while those for Ca, Ni and Cr in the dust storm were much lower than those in the non-dust-storm period due to significant local emission sources. A high concentration and enrichment factor for S were observed during the dust storm, which implies that the dust particles were contaminated by aerosol particles from anthropogenic emissions during the long-range transport. A statistical analysis shows that the elemental composition of particles collected during the dust storm in Beijing were better correlated with those of desert soil colleted from desert regions in Inner Mongolia. Air mass back-trajectory analysis further confirmed that this dust storm event could be identified as streaks of dust plumes originating from Inner Mongolia.

  20. Benthic invertebrate fauna, small streams

    Science.gov (United States)

    J. Bruce Wallace; S.L. Eggert

    2009-01-01

    Small streams (first- through third-order streams) make up >98% of the total number of stream segments and >86% of stream length in many drainage networks. Small streams occur over a wide array of climates, geology, and biomes, which influence temperature, hydrologic regimes, water chemistry, light, substrate, stream permanence, a basin's terrestrial plant...

  1. Dust appearance rates during neutral beam injection and after oxygen bake in the DIII-D tokamak

    International Nuclear Information System (INIS)

    Yu, J.H.; Smirnov, R.D.; Rudakov, D.L.

    2011-01-01

    A simple model to quantify source and sink terms of dust observed in tokamaks using fast visible imaging is presented. During neutral beam injection (NBI), dust appearance rates increase in front of the neutral beam port by up to a factor of 5. The images show dust streaming from the port box as previously settled dust becomes mobilized during beam injection. Following an oxygen bake and vent, the dust observation rate is a factor of 2 lower than that after a vessel entry vent with no oxygen bake. Detected dust levels decay on a shot-to-shot basis in a roughly exponential fashion, with a decay time of approximately 20 s of plasma exposure. Appearance rates of dust mass are estimated using assumed lognormal and power law functional forms for the dust size distribution. The two dust size distributions differ significantly on the amount the dust material carried by the largest particles, highlighting the need for further dust studies in order to make accurate forecasts to ITER.

  2. Chemical composition of streams during low flow; Fairfax County, Virginia

    Science.gov (United States)

    Larson, J.D.

    1978-01-01

    Water samples were collected and stream discharges were measured at 49 sites in Fairfax County, Virginia during a period of low flow in August 1977. In addition, pesticide and metal content of residue on stream-bottom sediments from several major streams in the county were analysed. Waters from the streams in Fairfax County have generally good chemical quality during low flow. One stream in Vienna, Virginia has a high sodium chloride content, suggesting an upstream discharge of salty water. Higher concentrations of dissolved, solids reflect both the effects of geology and urbanization. Streams draining Triassic rocks in the western section of the county are characterized by the greatest natural concentration of dissolved minerals in the water. The concentrations of pesticide and metal residue associated with bottom sediments suggest a low level of pollution in the streams. One site in western Fairfax County contained above-normal levels of polychlorinated biphenyls (PCB's) in the stream sediments.

  3. Chemical markers of occupational exposure to teak wood dust.

    Science.gov (United States)

    Carrieri, Mariella; Bartolucci, Giovanni Battista; Lee, Taekhee; Barbero, Ana; Harper, Martin

    2014-06-01

    A novel high-performance liquid chromatographic/ultraviolet method was developed to detect lapachol (LP) and deoxylapachol (DLP) in wood dust as chemical markers of teak wood (a suspected human carcinogen). The specificity of this analysis was determined by noting the absence of LP and DLP in 12 other specimens of different woods belonging to the angiosperm family. The consistency was examined by analyzing teak from three different sources, where the percentages (wt/wt) of the chemicals ranged from 0.006 to 0.261 for LP and from 0.038 to 0.497 for DLP, respectively. Although the LP and DLP components of teak varied according to source, a very high correlation coefficient (r (2) > 0.98 always) was found between the content of the two markers in the bulk specimens and in bulk dust derived from them. The method was then applied to teak dust collected on polyvinylchloride filters from aerosol in an exposure chamber in the range of mass loadings between 0.03 and 3.65 mg, which corresponds to a dust exposure between 0.124 and 8.703 mg m(-3) for a sampling time of 2h. A field test was also carried out in a small factory where teak was used. A good correlation was confirmed between LP and DLP versus the dust collected on the filter in both cases. LP and DLP can be markers to estimate the true quantities of teak dust inhaled in a workplace with mixed wood dust, provided the results are matched to the content of LP and DLP in the bulk wood. LP and DLP have also been proposed as the agents responsible for allergic reaction to teak dust. Therefore, it would be useful to evaluate the exposure to these two substances even without a relationship to teak dust exposure. © The Author 2014. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

  4. Composition of interstellar dust

    International Nuclear Information System (INIS)

    Field, G.B.

    1975-01-01

    Direct evidence that interstellar dust is composed partly of silicates, graphite, and water ice is reviewed. Indirect evidence, from recent studies of the chemical composition of interstellar gas, is assessed in terms of two possible models for the formation of the dust: condensation under thermal-equilibrium conditions and accretion under nonequilibrium conditions. It is concluded that probably the more refractory elements condense under equilibrium conditions and that probably the more volatile ones condense under nonequilibrium conditions. Equilibrium condensation may occur either in stellar atmospheres or in circumstellar nebulae, but arguments from stellar evolution favor the latter. If this is correct, all but a tiny fraction of the present interstellar medium has at least once been involved in circumstellar nebulae. This is consistent with the hypothesis that planetary systems are commonplace

  5. Quantifying dust plume formation and aerosol size distribution during the Saharan Mineral Dust Experiment in North Africa

    KAUST Repository

    Khan, Basit Ali

    2015-01-01

    Dust particles mixed in the free troposphere have longer lifetimes than airborne particles near the surface. Their cumulative radiative impact on earth’s meteorological processes and climate might be significant despite their relatively small contribution to total dust abundance. One example is the elevated dust--laden Saharan Air Layer (SAL) over the equatorial North Atlantic, which cools the sea surface and likely suppresses hurricane activity. To understand the formation mechanisms of SAL, we combine model simulations and dust observations collected during the first stage of the Saharan Mineral Dust Experiment (SAMUM--I), which sampled dust events that extended from Morocco to Portugal, and investigated the spatial distribution and the microphysical, optical, chemical, and radiative properties of Saharan mineral dust. We employed the Weather Research Forecast model coupled with the Chemistry/Aerosol module (WRF--Chem) to reproduce the meteorological environment and spatial and size distributions of dust. The experimental domain covers northwest Africa including the southern Sahara, Morocco and part of the Atlantic Ocean with 5 km horizontal grid spacing and 51 vertical layers. The experiments were run from 20 May to 9 June 2006, covering the period of most intensive dust outbreaks. Comparisons of model results with available airborne and ground--based observations show that WRF--Chem reproduces observed meteorological fields as well as aerosol distribution across the entire region and along the airplane’s tracks. We evaluated several aerosol uplift processes and found that orographic lifting, aerosol transport through the land/sea interface with steep gradients of meteorological characteristics, and interaction of sea breezes with the continental outflow are key mechanisms that form a surface--detached aerosol plume over the ocean. Comparisons of simulated dust size distributions with airplane and ground--based observations are generally good, but suggest

  6. Element and mineral characterization of dust emission from the saline land at Songnen Plain, Northeastern China.

    Science.gov (United States)

    Chen, Bing; Kitagawa, Hiroyuki; Hu, Ke; Jie, Dongmei; Yang, Junpeng; Li, Jingmin

    2009-01-01

    Recent observations of Asian dust storms show an eastern expansion of the source area to degraded lands, where dust emissions have been little studied. The dust concentrations over the saline land of the western Songnen Plain (SSL), Northeastern China, are circumstantially higher than those from the northwestern Chinese deserts. These concentrations are sensitive to the surface soil conditions and wind velocity on the ground. The dust samples collected during dust storm events on the SSL contain abundant Na, Mg, Al, K, Ca, Fe and Ti, as well as toxic elements such as Cu, V, Zn and Ba. Individual particle analysis reveals that fine saline particles (fine saline particles uplifted from the SSL are likely transported eastward by the winter monsoon circulation and westerlies. Recent degradation of saline lands in Northeastern China would not only increase the frequency of dust storm events in the downwind area, but also might change the chemical composition of the Asian dust emissions.

  7. Perfluorinated surfactants (PFSs) in size-fractionated street dust in Tokyo.

    Science.gov (United States)

    Murakami, Michio; Takada, Hideshige

    2008-11-01

    We investigated perfluorinated surfactants (PFSs) in size-fractionated street dust to identify their occurrence, contributions from traffic, and potential routes of entry into waters. Street dust was collected from residential areas and heavily trafficked areas in Tokyo and sorted into fine (fine fractions, PFS contents were significantly higher in heavily trafficked street dust than in residential street dust, but in coarse fractions, no significant differences were observed. Additionally, in heavily trafficked areas, PFS contents were significantly higher in fine fractions than in coarse fractions, but in residential areas, no significant differences were observed. PFS compositions differed between size fractions, not locations, indicating differences in sources between size fractions. Fine particles from traffic contributed to PFSs in street dust. Street dust possibly acts as the origin of PFSs in street runoff and eventually enters waters. This is the first report of PFSs in street dust.

  8. The Distribution of Interplanetary Dust Near 1-AU: An MMS Perspective

    Science.gov (United States)

    Adrian, M. L.; St Cyr, O. C.; Wilson, L. B., III; Schiff, C.; Sacks, L. W.; Chai, D. J.; Queen, S. Z.; Sedlak, J. E.

    2017-12-01

    The distribution of dust in the ecliptic plane in the vicinity of 1-AU has been inferred from impacts on the four Magnetospheric Multiscale (MMS) mission spacecraft as detected by the Acceleration Measurement System (AMS) during periods when no other spacecraft activities are in progress. Consisting of four identically instrumented spacecraft, with an inter-spacecraft separation ranging from 10-km to 400-km, the MMS constellation forms a dust "detector" with approximately four-times the collection area of any previous dust monitoring framework. Here we introduce the MMS-AMS and the inferred dust impact observations, provide a preliminary comparison of the MMS distribution of dust impacts to previously reported interplanetary dust distributions — namely those of the STEREO mission — and report on our initial comparison of the MMS distribution of dust impacts with known meteor showers.

  9. Dust acoustic shock wave at high dust density

    International Nuclear Information System (INIS)

    Ghosh, Samiran; Sarkar, Susmita; Khan, Manoranjan; Avinash, K.; Gupta, M. R.

    2003-01-01

    Dust acoustic (DA) shock wave at high dust density, i.e., the dust electroacoustic (DEA) or dust Coulomb (DC) shock wave has been investigated incorporating the nonadiabatic dust charge variation. The nonlinear DEA (DC) shock wave is seen to be governed by the Korteweg-de Vries Burger equation, in which the Burger term is proportional to the nonadiabaticity generated dissipation. It is seen that the shock strength decreases but after reaching minimum, it increases as the dust space charge density |q d n d | increases and the shock strength of DA wave is greater than that of DEA (DC) wave. Moreover the DEA (DC) shock width increases appreciably with increase mass m i of the ion component of the dusty plasma but for DA shock wave the effect is weak

  10. Dust, Climate, and Human Health

    Science.gov (United States)

    Maynard, Nancy G.

    2003-01-01

    Air pollution from both natural and anthropogenic causes is considered to be one of the most serious world-wide environment-related health problems, and is expected to become worse with changes in the global climate. Dust storms from the atmospheric transport of desert soil dust that has been lifted and carried by the winds - often over significant distances - have become an increasingly important emerging air quality issue for many populations. Recent studies have shown that the dust storms can cause significant health impacts from the dust itself as well as the accompanying pollutants, pesticides, metals, salt, plant debris, and other inorganic and organic materials, including viable microorganisms (bacteria, viruses and fungi). For example, thousands of tons of Asian desert sediments, some containing pesticides and herbicides from farming regions, are commonly transported into the Arctic during dust storm events. These chemicals have been identified in animal and human tissues among Arctic indigenous populations. Millions of tons of airborne desert dust are being tracked by satellite imagery, which clearly shows the magnitude as well as the temporal and spatial variability of dust storms across the "dust belt" regions of North Africa, the Middle East, and China. This paper summarizes the most recent findings on the effects of airborne desert dust on human health as well as potential climate influences on dust and health.

  11. Solar wind stream interfaces

    International Nuclear Information System (INIS)

    Gosling, J.T.; Asbridge, J.R.; Bame, S.J.; Feldman, W.C.

    1978-01-01

    Measurements aboard Imp 6, 7, and 8 reveal that approximately one third of all high-speed solar wind streams observed at 1 AU contain a sharp boundary (of thickness less than approx.4 x 10 4 km) near their leading edge, called a stream interface, which separates plasma of distinctly different properties and origins. Identified as discontinuities across which the density drops abruptly, the proton temperature increases abruptly, and the speed rises, stream interfaces are remarkably similar in character from one stream to the next. A superposed epoch analysis of plasma data has been performed for 23 discontinuous stream interfaces observed during the interval March 1971 through August 1974. Among the results of this analysis are the following: (1) a stream interface separates what was originally thick (i.e., dense) slow gas from what was originally thin (i.e., rare) fast gas; (2) the interface is the site of a discontinuous shear in the solar wind flow in a frame of reference corotating with the sun; (3) stream interfaces occur at speeds less than 450 km s - 1 and close to or at the maximum of the pressure ridge at the leading edges of high-speed streams; (4) a discontinuous rise by approx.40% in electron temperature occurs at the interface; and (5) discontinuous changes (usually rises) in alpha particle abundance and flow speed relative to the protons occur at the interface. Stream interfaces do not generally recur on successive solar rotations, even though the streams in which they are embedded often do. At distances beyond several astronomical units, stream interfaces should be bounded by forward-reverse shock pairs; three of four reverse shocks observed at 1 AU during 1971--1974 were preceded within approx.1 day by stream interfaces. Our observations suggest that many streams close to the sun are bounded on all sides by large radial velocity shears separating rapidly expanding plasma from more slowly expanding plasma

  12. Measuring suspended sediment in small mountain streams

    Science.gov (United States)

    Robert B. Thomas

    1985-01-01

    Measuring suspended sediment concentration in streams provides a way of monitoring the effects of forest management activities on water quality. Collecting data on suspended sediment is an act of sampling. The nature of the delivery process and the circumstances under which data are collected combine to produce highly variable results that are difficult to analyze and...

  13. Dust fallout in Kuwait city: deposition and characterization.

    Science.gov (United States)

    Al-Awadhi, Jasem M; Alshuaibi, Arafat A

    2013-09-01

    Dust fallouts in Kuwait city was monitored on monthly basis during the period from March 2011 to February 2012 at 10 locations. The results of this study reveal that: (1) monthly dust deposition rates ranged from 0.002 to 0.32 kg/m(2) with average deposition rate of 0.053 kg/m(2) and annual average deposition rate of 0.59 kg/m(2), ranking the first out of 56 dust deposition rates observed throughout the world; (2) on average, about 55.9% of the settled dust have fine to very fine sand fraction sizes, while silt and clay comprise an average of 37.4 and 1.4% of the total sample, respectively; (3) the concentrations for Zn and Mo out of 15 other elements analyzed from the dust were up to 11 times higher than their soil background values in Kuwait, while Pb and Ni were about seven times higher; (4) Mo, Ni, Pb and Zn show maximum enrichment relative to the upper continental crustal component (Mn); (5) Sr, Zr and Zn show highest concretions among all collected samples; and (6) quartz and calcite were the dominant minerals in the dust samples. The distribution of the heavy metals in dust seems to be controlled mainly by the land uses and the volume of traffic emissions. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Dust vortices, clouds, and jets in nuclear-induced plasmas

    International Nuclear Information System (INIS)

    Vladimirov, V.I.; Deputatova, L.V.; Nefedov, A.P.; Fortov, V.E.; Rykov, V.A.; Khudyakov, A.V.

    2001-01-01

    The collective movement of dust particles in a plasma formed during deceleration of decay products of californium nuclei in neon is investigated experimentally. For the first time, compact vortex structures containing a large number of coagulating dust particles and dense dust clouds evolving in time are observed. Dust formations have clearly defined boundaries and particles in them form ordered liquid-type structures. Under steady-state conditions, dust structures exist from several minutes to hours. An increase in the voltage applied to the high-voltage electrode leads to the formation of dust particle jets. A change in the electric field configuration transforms the structures from one type to another. A strong recombination of electrons and ions at dust particles is observed. The momentum transfer from ions drifting in an external field to gas molecules is studied using the Monte Carlo method. It is shown that the transferred momentum is so large that it may cause a gas flow. The characteristic features of vortex flow in neon and in air are explained

  15. Building an industry-wide occupational exposure database for respirable mineral dust - experiences from the IMA dust monitoring programme

    International Nuclear Information System (INIS)

    Houba, Remko; Jongen, Richard; Vlaanderen, Jelle; Kromhout, Hans

    2009-01-01

    Building an industry-wide database with exposure measurements of respirable mineral dust is a challenging operation. The Industrial Minerals Association (IMA-Europe) took the initiative to create an exposure database filled with data from a prospective and ongoing dust monitoring programme that was launched in 2000. More than 20 industrial mineral companies have been collecting exposure data following a common protocol since then. Recently in 2007 ArboUnie and IRAS evaluated the quality of the collected exposure data for data collected up to winter 2005/2006. The data evaluated was collected in 11 sampling campaigns by 24 companies at 84 different worksites and considered about 8,500 respirable dust measurements and 7,500 respirable crystalline silica. In the quality assurance exercise four criteria were used to evaluate the existing measurement data: personal exposure measurements, unique worker identity, sampling duration not longer than one shift and availability of a limit of detection. Review of existing exposure data in the IMA dust monitoring programme database showed that 58% of collected respirable dust measurements and 62% of collected respirable quartz could be regarded as 'good quality data' meeting the four criteria mentioned above. Only one third of the measurement data included repeated measurements (within a sampling campaign) that would allow advanced statistical analysis incorporating estimates of within- and between-worker variability in exposure to respirable mineral dust. This data came from 7 companies comprising measurements from 23 sites. Problematic data was collected in some specific countries and to a large extent this was due to local practices and legislation (e.g. allowing 40-h time weighted averages). It was concluded that the potential of this unique industry-wide exposure database is very high, but that considerable improvements can be made. At the end of 2006 relatively small but essential changes were made in the dust monitoring

  16. Large aperture electrostatic dust detector

    International Nuclear Information System (INIS)

    Skinner, C.H.; Hensley, R.; Roquemore, A.L.

    2008-01-01

    Diagnosis and management of dust inventories generated in next-step magnetic fusion devices is necessary for their safe operation. A novel electrostatic dust detector, based on a fine grid of interlocking circuit traces biased to 30 or 50 V has been developed for the detection of dust particles on remote surfaces in air and vacuum environments. Impinging dust particles create a temporary short circuit and the resulting current pulse is recorded by counting electronics. Up to 90% of the particles are ejected from the grid or vaporized suggesting the device may be useful for controlling dust inventories. We report measurements of the sensitivity of a large area (5 x 5 cm) detector to microgram quantities of dust particles

  17. Large Aperture Electrostatic Dust Detector

    International Nuclear Information System (INIS)

    Skinner, C.H.; Hensley, R.; Roquemore, A.L.

    2007-01-01

    Diagnosis and management of dust inventories generated in next-step magnetic fusion devices is necessary for their safe operation. A novel electrostatic dust detector, based on a fine grid of interlocking circuit traces biased to 30 or 50 v has been developed for the detection of dust particles on remote surfaces in air and vacuum environments. Impinging dust particles create a temporary short circuit and the resulting current pulse is recorded by counting electronics. Up to 90% of the particles are ejected from the grid or vaporized suggesting the device may be useful for controlling dust inventories. We report measurements of the sensitivity of a large area (5x5 cm) detector to microgram quantities of dust particles and review its applications to contemporary tokamaks and ITER.

  18. StreamStats, version 4

    Science.gov (United States)

    Ries, Kernell G.; Newson, Jeremy K.; Smith, Martyn J.; Guthrie, John D.; Steeves, Peter A.; Haluska, Tana L.; Kolb, Katharine R.; Thompson, Ryan F.; Santoro, Richard D.; Vraga, Hans W.

    2017-10-30

    IntroductionStreamStats version 4, available at https://streamstats.usgs.gov, is a map-based web application that provides an assortment of analytical tools that are useful for water-resources planning and management, and engineering purposes. Developed by the U.S. Geological Survey (USGS), the primary purpose of StreamStats is to provide estimates of streamflow statistics for user-selected ungaged sites on streams and for USGS streamgages, which are locations where streamflow data are collected.Streamflow statistics, such as the 1-percent flood, the mean flow, and the 7-day 10-year low flow, are used by engineers, land managers, biologists, and many others to help guide decisions in their everyday work. For example, estimates of the 1-percent flood (which is exceeded, on average, once in 100 years and has a 1-percent chance of exceedance in any year) are used to create flood-plain maps that form the basis for setting insurance rates and land-use zoning. This and other streamflow statistics also are used for dam, bridge, and culvert design; water-supply planning and management; permitting of water withdrawals and wastewater and industrial discharges; hydropower facility design and regulation; and setting of minimum allowed streamflows to protect freshwater ecosystems. Streamflow statistics can be computed from available data at USGS streamgages depending on the type of data collected at the stations. Most often, however, streamflow statistics are needed at ungaged sites, where no streamflow data are available to determine the statistics.

  19. Streaming Visual Analytics Workshop Report

    Energy Technology Data Exchange (ETDEWEB)

    Cook, Kristin A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Burtner, Edwin R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kritzstein, Brian P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Brisbois, Brooke R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Mitson, Anna E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-03-31

    How can we best enable users to understand complex emerging events and make appropriate assessments from streaming data? This was the central question addressed at a three-day workshop on streaming visual analytics. This workshop was organized by Pacific Northwest National Laboratory for a government sponsor. It brought together forty researchers and subject matter experts from government, industry, and academia. This report summarizes the outcomes from that workshop. It describes elements of the vision for a streaming visual analytic environment and set of important research directions needed to achieve this vision. Streaming data analysis is in many ways the analysis and understanding of change. However, current visual analytics systems usually focus on static data collections, meaning that dynamically changing conditions are not appropriately addressed. The envisioned mixed-initiative streaming visual analytics environment creates a collaboration between the analyst and the system to support the analysis process. It raises the level of discourse from low-level data records to higher-level concepts. The system supports the analyst’s rapid orientation and reorientation as situations change. It provides an environment to support the analyst’s critical thinking. It infers tasks and interests based on the analyst’s interactions. The system works as both an assistant and a devil’s advocate, finding relevant data and alerts as well as considering alternative hypotheses. Finally, the system supports sharing of findings with others. Making such an environment a reality requires research in several areas. The workshop discussions focused on four broad areas: support for critical thinking, visual representation of change, mixed-initiative analysis, and the use of narratives for analysis and communication.

  20. Stream, Lake, and Reservoir Management.

    Science.gov (United States)

    Dai, Jingjing; Mei, Ying; Chang, Chein-Chi

    2017-10-01

    This review on stream, lake, and reservoir management covers selected 2016 publications on the focus of the following sections: Stream, lake, and reservoir management • Water quality of stream, lake, and reservoir • Reservoir operations • Models of stream, lake, and reservoir • Remediation and restoration of stream, lake, and reservoir • Biota of stream, lake, and reservoir • Climate effect of stream, lake, and reservoir.

  1. Hydrography - Streams and Shorelines

    Data.gov (United States)

    California Natural Resource Agency — The hydrography layer consists of flowing waters (rivers and streams), standing waters (lakes and ponds), and wetlands -- both natural and manmade. Two separate...

  2. Hydrography - Streams and Shorelines

    Data.gov (United States)

    California Department of Resources — The hydrography layer consists of flowing waters (rivers and streams), standing waters (lakes and ponds), and wetlands -- both natural and manmade. Two separate...

  3. Dynamics of meteor streams

    International Nuclear Information System (INIS)

    Babadjanov, P.B.; Obrubov, YU.U.

    1987-01-01

    The overwhelming majority of meteor streams are generally assumed to be formed due to the decay of comets. The most effective process of the release of solid particles from a cometary nucleus is their ejection by sublimating gases when the comet approaches the Sun. The results of investigation of the Geminids and Quadrantids meteor stream evolution show that under the influence of planetary perturbations, the stream may originally be flat but then thicken depending on the variation range of orbital inclinations. Eventually, due to planetary perturbations, a meteor stream may take such a shape as to cause the start of several active showers at different solar longitudes

  4. Inventory of miscellaneous streams

    International Nuclear Information System (INIS)

    Lueck, K.J.

    1995-09-01

    On December 23, 1991, the US Department of Energy, Richland Operations Office (RL) and the Washington State Department of Ecology (Ecology) agreed to adhere to the provisions of the Department of Ecology Consent Order. The Consent Order lists the regulatory milestones for liquid effluent streams at the Hanford Site to comply with the permitting requirements of Washington Administrative Code. The RL provided the US Congress a Plan and Schedule to discontinue disposal of contaminated liquid effluent into the soil column on the Hanford Site. The plan and schedule document contained a strategy for the implementation of alternative treatment and disposal systems. This strategy included prioritizing the streams into two phases. The Phase 1 streams were considered to be higher priority than the Phase 2 streams. The actions recommended for the Phase 1 and 2 streams in the two reports were incorporated in the Hanford Federal Facility Agreement and Consent Order. Miscellaneous Streams are those liquid effluents streams identified within the Consent Order that are discharged to the ground but are not categorized as Phase 1 or Phase 2 Streams. This document consists of an inventory of the liquid effluent streams being discharged into the Hanford soil column

  5. How well can we quantify dust deposition to the ocean?

    Science.gov (United States)

    Cheng, H.; Edwards, R. L.; Fleisher, M. Q.; Hayes, C. T.; Huang, K.-F.; Kadko, D.; Lam, P. J.; Landing, W. M.; Lao, Y.; Lu, Y.; Measures, C. I.; Moran, S. B.; Morton, P. L.; Ohnemus, D. C.; Robinson, L. F.; Shelley, R. U.

    2016-01-01

    Deposition of continental mineral aerosols (dust) in the Eastern Tropical North Atlantic Ocean, between the coast of Africa and the Mid-Atlantic Ridge, was estimated using several strategies based on the measurement of aerosols, trace metals dissolved in seawater, particulate material filtered from the water column, particles collected by sediment traps and sediments. Most of the data used in this synthesis involve samples collected during US GEOTRACES expeditions in 2010 and 2011, although some results from the literature are also used. Dust deposition generated by a global model serves as a reference against which the results from each observational strategy are compared. Observation-based dust fluxes disagree with one another by as much as two orders of magnitude, although most of the methods produce results that are consistent with the reference model to within a factor of 5. The large range of estimates indicates that further work is needed to reduce uncertainties associated with each method before it can be applied routinely to map dust deposition to the ocean. Calculated dust deposition using observational strategies thought to have the smallest uncertainties is lower than the reference model by a factor of 2–5, suggesting that the model may overestimate dust deposition in our study area. This article is part of the themed issue ‘Biological and climatic impacts of ocean trace element chemistry’. PMID:29035251

  6. Global transport of thermophilic bacteria in atmospheric dust.

    Science.gov (United States)

    Perfumo, Amedea; Marchant, Roger

    2010-04-01

    Aerosols from dust storms generated in the Sahara-Sahel desert area of Africa are transported north over Europe and periodically result in dry dust precipitation in the Mediterranean region. Samples of dust collected in Turkey and Greece following two distinct desert storm events contained viable thermophilic organisms of the genus Geobacillus, namely G. thermoglucosidasius and G. thermodenitrificans, and the recently reclassified Aeribacillus pallidus (formerly Geobacillus pallidus). We present here evidence that African dust storms create an atmospheric bridge between distant geographical regions and that they are also probably the source of thermophilic geobacilli later deposited over northern Europe by rainfall or dust plumes themselves. The same organisms (99% similarity in the 16S rDNA sequence) were found in dust collected in the Mediterranean region and inhabiting cool soils in Northern Ireland. This study also contributes new insights to the taxonomic identification of Geobacillus sp. Attempts to identify these organisms using 16S rRNA gene sequences have revealed that they contain multiple and diverse copies of the ribosomal RNA operon (up to 10 copies with nine different sequences), which dictates care in interpreting data about the systematics of this genus. © 2010 Society for Applied Microbiology and Blackwell Publishing Ltd.

  7. Bakers' exposure to flour dust.

    Science.gov (United States)

    Kirkeleit, Jorunn; Hollund, Bjørg Eli; Riise, Trond; Eduard, Wijnand; Bråtveit, Magne; Storaas, Torgeir

    2017-02-01

    We aimed to characterize bakers' personal exposure to airborne flour dust with respect to the health-related aerosol fractions inhalable, extrathoracic, and thoracic dust, and to examine possible production-related determinants of dust exposure. Sixty-eight bakers from 7 bakeries in Bergen, Norway (2009-2012) participated in the exposure assessment, comprising full-shift personal samples of inhalable dust (n = 107) and thoracic dust (n = 61). The relation between possible determinants and exposure was estimated using mixed effects models, while associations between the various aerosol fractions across task groups and type of bakeries were described by Pearson's correlation coefficients. Bakers' overall geometric mean personal exposure to inhalable, extrathoracic, and thoracic dust were 2.6 mg/m 3 (95% CI: 2.0, 3.2), 2.2 mg/m 3 (95% CI: 1.9, 2.7), and 0.33 mg/m 3 (95% CI 0.3, 0.4), respectively. A total of 29% of the measurements of inhalable dust were above the Norwegian Occupational Exposure Limit of 3 mg/m 3 . The exposure variability of inhalable dust could not be explained by any of the examined production-related determinants, while the daily production volume explained 18% of the variance in thoracic dust exposure. Overall, the thoracic dust represented 15% of the inhalable dust, being rather stable across the production-related determinants. The overall correlation between inhalable and thoracic dust was nevertheless moderate (r = 0.52, p bakers (r = 0.62) and no correlation during dough forming (r = 0.01). Bakers are exposed to flour dust at a level that most likely represents an excess risk of developing chronic diseases of the respiratory system, and a decrease of present exposure level is imperative. Extrathoracic dust-likely the most relevant sub-fraction in respect to flour-induced sensitization and occupational rhinitis-represented the main proportion of the measured inhalable dust. The variation in correlation coefficients between the dust fractions

  8. Dust in cosmic plasma environments

    International Nuclear Information System (INIS)

    Mendis, D.A.

    1979-01-01

    Cosmic dust is invariably immersed in a plasma and a radiative environment. Consequently, it is charged to some electrostatic potential which depends on the properties of the environment as well as the nature of the dust. This charging affects the physical and dynamical properties of the dust. In this paper the basic aspects of this dust-plasma interaction in several cosmic environments - including planetary magnetospheres, the heliosphere and the interstellar medium - are discussed. The physical and dynamical consequences of the interaction, as well as the pertinent observational evidence, are reviewed. Finally, the importance of the surface charge during the condensation process in plasma environments is stressed. (Auth.)

  9. An analysis of the correlation between dust storms in Korea and 137Cs nuclide concentration

    International Nuclear Information System (INIS)

    Choi, Soo-won; Kim, Jeong-hun; Shin, Sang-hwa; Hwang, Joo-ho

    2008-01-01

    Dust storms occur in Korea during spring time when fine dust is blown in from the far western regions of western China and Mongolia. A fine powdery dust is blown up into the sky and enters the upper reaches of the atmosphere where it is carried easterly across China then slowly falls to the ground on the Korean peninsula and Japan. The dust originates mostly in the Gobi dessert of China, as well as the yellow earth regions in the middle and upper streams of the Yellow river in China. Previous studies on dust storms have been limited to following or estimating their courses, distribution and frequency, or distribution of the heavy metals they transmit. However, since radionuclides exist in the dust, they must also exist in the dust storms. In this study, we analyzed the correlation of :1 37 Cs nuclide concentration based on a count of annual dust storm occurrence in the city of Suwon, South Korea and assessed seasonal differences of 137 Cs nuclide concentration

  10. Dust plume formation in the free troposphere and aerosol size distribution during the Saharan Mineral Dust Experiment in North Africa

    KAUST Repository

    Khan, Basit Ali

    2015-11-27

    Dust particles mixed in the free troposphere have longer lifetimes than airborne particles near the surface. Their cumulative radiative impact on earth’s meteorological processes and climate might be significant despite their relatively small contribution to total dust abundance. One example is the elevated dust-laden Saharan Air Layer (SAL) over the tropical and subtropical North Atlantic, which cools the sea surface. To understand the formation mechanisms of a dust layer in the free troposphere, this study combines model simulations and dust observations collected during the first stage of the Saharan Mineral Dust Experiment (SAMUM-I), which sampled dust events that extended from Morocco to Portugal, and investigated the spatial distribution and the microphysical, optical, chemical, and radiative properties of Saharan mineral dust. The Weather Research Forecast model coupled with the Chemistry/Aerosol module (WRF-Chem) is employed to reproduce the meteorological environment and spatial and size distributions of dust. The model domain covers northwest Africa and adjacent water with 5 km horizontal grid spacing and 51 vertical layers. The experiments were run from 20 May to 9 June 2006, covering the period of the most intensive dust outbreaks. Comparisons of model results with available airborne and ground-based observations show that WRF-Chem reproduces observed meteorological fields as well as aerosol distribution across the entire region and along the airplane’s tracks. Several mechanisms that cause aerosol entrainment into the free troposphere are evaluated and it is found that orographic lifting, and interaction of sea breeze with the continental outflow are key mechanisms that form a surface-detached aerosol plume over the ocean. The model dust emission scheme is tuned to simultaneously fit the observed total optical depth and the ratio of aerosol optical depths generated by fine and coarse dust modes. Comparisons of simulated dust size distributions with

  11. Stardust: Comet and interstellar dust sample return mission

    Science.gov (United States)

    Brownlee, D. E.; Tsou, P.; Anderson, J. D.; Hanner, M. S.; Newburn, R. L.; Sekanina, Z.; Clark, B. C.; Hörz, F.; Zolensky, M. E.; Kissel, J.; McDonnell, J. A. M.; Sandford, S. A.; Tuzzolino, A. J.

    2003-10-01

    Stardust, the 4th Discovery mission launched in February 1999, will collect coma samples from the recently deflected comet 81P/Wild 2 on 2 January 2004 and return them to Earth on 15 January 2006 for detailed laboratory analyses. Stardust will be the first mission to bring samples back to Earth from a known comet and also the first to bring back contemporary interstellar particles recently discovered. These samples should provide important insights into the nature and amount of dust released by comets, the roles of comets in planetary systems, clues to the importance of comets in producing dust in our zodiacal cloud as well as circumstellar dust around other stars, and the links between collected meteoritic samples with a known cometary body. Samples are collected in newly invented continuous gradient density silica aerogel. Stardust is facilitated by a magnificent trajectory designed to accomplish a complex and ambitious flyby sample return mission within the Discovery program restrictions. The remaining science payload, which provides important context for the captured samples, includes a time-of-flight spectrometer measuring the chemical and isotopic composition of dust grains; a polyvinylidene fluoride dust flux monitor determining dust flux profiles; a CCD camera for imaging Wild 2 coma and its nucleus; a shared X band transponder providing two-way Doppler shifts to estimate limits to Wild 2 mass and integrated dust fluence; and tracking of the spacecraft's attitude sensing for the detection of large particle impacts. The graphite composite spacecraft brings the collected sample back to Earth by a direct reentry in a capsule.

  12. Laboratory investigations of the impact of mineral dust aerosol on cold cloud formation

    OpenAIRE

    K. A. Koehler; S. M. Kreidenweis; P. J. DeMott; M. D. Petters; A. J. Prenni; O. Möhler

    2010-01-01

    Dust particles represent a dominant source of particulate matter (by mass) to the atmosphere, and their emission from some source regions has been shown to be transported on regional and hemispherical scales. Dust particles' potential to interact with water vapor in the atmosphere can lead to important radiative impacts on the climate system, both direct and indirect. We have investigated this interaction for several types of dust aerosol, collected from the Southwestern Uni...

  13. Investigations of the impact of natural dust aerosol on cold cloud formation

    OpenAIRE

    K. A. Koehler; S. M. Kreidenweis; P. J. DeMott; M. D. Petters; A. J. Prenni; O. Möhler

    2010-01-01

    Dust particles represent a dominant source of particulate matter (by mass) to the atmosphere, and their emission from some source regions has been shown to be transported on regional and hemispherical scales. Dust particles' potential to interact with water vapor in the atmosphere can lead to important radiative impacts on the climate system, both direct and indirect. We have investigated this interaction for several types of dust aerosol, collected from the Southwestern United States and the...

  14. EMC Test Report Electrodynamic Dust Shield

    Science.gov (United States)

    Carmody, Lynne M.; Boyette, Carl B.

    2014-01-01

    This report documents the Electromagnetic Interference E M I evaluation performed on the Electrodynamic Dust Shield (EDS) which is part of the MISSE-X System under the Electrostatics and Surface Physics Laboratory at Kennedy Space Center. Measurements are performed to document the emissions environment associated with the EDS units. The purpose of this report is to collect all information needed to reproduce the testing performed on the Electrodynamic Dust Shield units, document data gathered during testing, and present the results. This document presents information unique to the measurements performed on the Bioculture Express Rack payload; using test methods prepared to meet SSP 30238 requirements. It includes the information necessary to satisfy the needs of the customer per work order number 1037104. The information presented herein should only be used to meet the requirements for which it was prepared.

  15. Dust coagulation in ISM

    Science.gov (United States)

    Chokshi, Arati; Tielens, Alexander G. G. M.; Hollenbach, David

    1989-01-01

    Coagulation is an important mechanism in the growth of interstellar and interplanetary dust particles. The microphysics of the coagulation process was theoretically analyzed as a function of the physical properties of the coagulating grains, i.e., their size, relative velocities, temperature, elastic properties, and the van der Waal interaction. Numerical calculations of collisions between linear chains provide the wave energy in individual particles and the spectrum of the mechanical vibrations set up in colliding particles. Sticking probabilities are then calculated using simple estimates for elastic deformation energies and for the attenuation of the wave energy due to absorption and scattering processes.

  16. Gravitational radiation from dust

    International Nuclear Information System (INIS)

    Isaacson, R.A.; Welling, J.S.; Winicour, J.

    1985-01-01

    A dust cloud is examined within the framework of the general relativistic characteristic initial value problem. Unique gravitational initial data are obtained by requiring that the space-time be quasi-Newtonian. Explicit calculations of metric and matter fields are presented, which include all post-Newtonian corrections necessary to discuss the major physical properties of null infinity. These results establish a curved space version of the Einstein quadrupole formula, in the form ''news function equals third time derivative of transverse quadrupole moment,'' for this system. However, these results imply that some weakened notion of asymptotic flatness is necessary for the description of quasi-Newtonian systems

  17. Ecological health in the Nation's streams

    Science.gov (United States)

    Carlisle, Daren M.; Woodside, Michael D.

    2013-01-01

    Aquatic biological communities, which are collections of organisms, are a direct measure of stream health because they indicate the ability of a stream to support life. This fact sheet highlights selected findings of a national assessment of stream health by the National Water-Quality Assessment (NAWQA) Program of the U.S. Geological Survey (USGS). The assessment was unique in that it integrated the condition of three biological communities—algae, macroinvertebrates, and fish—as well as measures of streamflow modification, pesticides, nutrients, and other factors. At least one biological community was altered at 83 percent of assessed streams, and the occurrence of altered communities was highest in urban streams. Streamflows were modified at 86 percent of assessed streams, and increasing severity of streamflow modification was associated with increased occurrence of altered biological communities. Agricultural and urban land use in watersheds may contribute pesticides and nutrients to stream waters, and increasing concentrations of these chemicals were associated with increased occurrence of altered biological communities.

  18. Dust confinement and dust acoustic waves in a magnetized plasma

    Science.gov (United States)

    Piel, A.

    2005-10-01

    Systematic laboratory experiments on dust acoustic waves require the confinement of dust particles. Here we report on new experiments in a magnetized plasma region in front of an additional positively biased disk electrode in a background plasma which is generated in argon at 27MHz between a disk and grid electrode. The plasma diffuses through the grid along the magnetic field. The three-dimensional dust distribution is measured with a horizontal sheet of laser light and a CCD camera, which are mounted on a vertical translation stage. Depending on magnetic field and discharge current, cigar or donut-shaped dust clouds are generated, which tend to rotate about the magnetic field direction. Measurements with emissive probes show that the axial confinement of dust particles with diameters between 0.7-2 μm is achieved by a balance of ion-drag force and electric field force. Dust levitation and radial confinement is due to a strong radial electric field. Dust acoustic waves are destabilized by the ion flow or can be stimulated by a periodic bias on the disk electrode. The observed wave dispersion is compared with fluid and kinetic models of the dust acoustic wave.

  19. Gravimetric dust sampling for control purposes and occupational dust sampling.

    CSIR Research Space (South Africa)

    Unsted, AD

    1997-02-01

    Full Text Available Prior to the introduction of gravimetric dust sampling, konimeters had been used for dust sampling, which was largely for control purposes. Whether or not absolute results were achievable was not an issue since relative results were used to evaluate...

  20. Dust-Medicane Interaction: Tropical-Like Cyclone on November 7th, 2014

    Science.gov (United States)

    Isik, A. G.

    2017-12-01

    Mineral dust aerosols, soil particles suspended in the atmosphere, play a vital role in climate and can alter weather systems. Those particles have both direct (dust-radiation effect) and indirect (dust-microphysical effect) impacts on the energy budget. This study aims to investigate the dust impact on tropical-like cyclones over the Mediterranean Basin. Tropical-like cyclones (TLCs) called Medicanes (MEDIterranean hurriCANE) are rare cases observed in the Mediterranean Sea. On average, one TLC case is caught by satellite images in the Mediterranean basin. Moreover, tropical cyclone (TC) activity over Atlantic region peaks during summer and early fall while TLCs occur in September, October and November. There are many studies examining the relation between Saharan dust and TC development over Atlantic. TC's environmental conditions could be influenced by dust. An environment with weaker vertical wind shear is more favorable to TC development. Similar to TCs, TLCs require minimal wind shear and abundant amount of moisture and vorticity. However, there are not many studies related to dust impact on medicanes. This study tries to find out if dust transport could effect medicane formation and development. One of the objectives of the study is to analyze the medicane and dust transport by satellite data. For this purpose, Medicane case on 7th of November, 2014 was chosen. The TLC formed early on November 7th, hit eastern Sicily. It was dissipated on 8th of November. A strong low level jet-stream blew warm air masses from the Sahara desert towards the Mediterranean. Another objective is to study the dust-medicane interaction over Mediterranean Sea in 2014 using a numerical model. The case simulated with WRF will enlighten the interaction between dust and TLC activity. Furthermore, more studies in different TLC cases and simulations with different physics options will give insight into the interaction.

  1. Natural variability versus human impact: Hydroclimate variability and the role of agriculture in changing dust emissions from Australia.

    Science.gov (United States)

    Marx, Samuel; Kamber, Balz; McGowan, Hamish; Hooper, James; Zawadzki, Atun

    2016-04-01

    Broad-scale dust emissions play an important role in Earth systems, for example influencing oceanic productivity via phytoplankton fertilisation. Existing palaeo dust records show that dust emissions vary significantly in time, implying its impact is similarly variable. There remains, however, a paucity of records which quantify variability in dust emissions. This study presents continuous, Holocene-aged, records of dust emissions from Australia, an important global dust source. Records demonstrate that rates of dust export have varied by 8-30 times over the mid to late Holocene. This variability is largely attributed to hydroclimate variability and its associated feedbacks within dust source areas. Significantly, however, a major disruption of dust emission rates is recorded in the past 200 years when dust emissions increased by between 2-10 times rates of natural variability in dust export. This change is concomitant with the arrival of Europeans in Australia and is primarily attributed to the development of agriculture which resulted in unprecedented environmental change in Australia's arid interior. This result broadly accords with the few other existing empirical dust records which both pre-date and post-date the onset of agriculture in various arid and semi-arid regions. Collectively, these records imply the impact of dust in Earth systems has changed as a result of agricultural development.

  2. Benthic algae of benchmark streams in agricultural areas of eastern Wisconsin

    Science.gov (United States)

    Scudder, Barbara C.; Stewart, Jana S.

    2001-01-01

    Benthic algae were collected from 20 streams in the Western Lake Michigan Drainages by the U.S. Geological Survey in May and June of 1993 as part of the National Water-Quality Assessment program. These streams were selected to represent "benchmark" streams that were minimally affected by human activities, especially agriculture, for comparison to other streams in similar environmental settings. Streams were chosen from four relatively homogeneous units (RHU's) in agricultural areas with differing texture of surficial deposits and bedrock type.

  3. Integrated assessment of sources, chemical stressors and stream quality along a groundwater fed stream system

    Science.gov (United States)

    Løgstrup Bjerg, Poul; Sonne, Anne T.; Rønde, Vinni; McKnight, Ursula S.

    2016-04-01

    Streams are impacted by significant contamination at the catchment scale, as they are often locations of multiple chemical stressor inputs. The European Water Framework Directive requires EU member states to ensure good chemical and ecological status of surface water bodies by 2027. This requires monitoring of stream water quality, comparison with environmental quality standards (EQS) and assessment of ecological status. However, the achievement of good status of stream water also requires a strong focus on contaminant sources, pathways and links to stream water impacts, so source management and remedial measures can be implemented. Fate and impacts of different contaminant groups are governed by different processes and are dependent on the origin (geogenic, anthropogenic), source type (point or diffuse) and pathway of the contaminant. To address this issue, we identified contaminant sources and chemical stressors on a groundwater-fed stream to quantify the contaminant discharges, link the chemical impact and stream water quality and assess the main chemical risk drivers in the stream system potentially driving ecological impact. The study was conducted in the 8 m wide Grindsted stream (Denmark) along a 16 km stream stretch that is potentially impacted by two contaminated sites (Grindsted Factory site, Grindsted Landfill), fish farms, waste water discharges, and diffuse sources from agriculture and urban areas. Water samples from the stream and the hyporheic zone as well as bed sediment samples were collected during three campaigns in 2012 and 2014. Data for xenobiotic organic groundwater contaminants, pesticides, heavy metals, general water chemistry, physical conditions and stream flow were collected. The measured chemical concentrations were converted to toxic units (TU) based on the 48h acute toxicity tests with D. magna. The results show a substantial impact of the Grindsted Factory site at a specific stretch of the stream. The groundwater plume caused

  4. LHCb trigger streams optimization

    Science.gov (United States)

    Derkach, D.; Kazeev, N.; Neychev, R.; Panin, A.; Trofimov, I.; Ustyuzhanin, A.; Vesterinen, M.

    2017-10-01

    The LHCb experiment stores around 1011 collision events per year. A typical physics analysis deals with a final sample of up to 107 events. Event preselection algorithms (lines) are used for data reduction. Since the data are stored in a format that requires sequential access, the lines are grouped into several output file streams, in order to increase the efficiency of user analysis jobs that read these data. The scheme efficiency heavily depends on the stream composition. By putting similar lines together and balancing the stream sizes it is possible to reduce the overhead. We present a method for finding an optimal stream composition. The method is applied to a part of the LHCb data (Turbo stream) on the stage where it is prepared for user physics analysis. This results in an expected improvement of 15% in the speed of user analysis jobs, and will be applied on data to be recorded in 2017.

  5. Of data and dust

    CERN Multimedia

    Stephanie Hills

    2016-01-01

    The traditional image of an archive is one of dusty old boxes, books and papers. When your archive is digital, dust spells disaster. An innovative environmental sensor designed and built by a CERN IT specialist has become an essential element in the Laboratory’s data-preservation strategy.   The novel air particle monitoring sensor designed by CERN's Julien Leduc. CERN’s archive holds more than 130 petabytes of data from past and present high-energy physics experiments. Some of it is 40 years old, most of it needs to be kept forever, and all of it is held on tape cartridges (over 20,000 of them). The cartridges are held inside tape libraries with robotic arms that load them into tape drives where they can be read and written. Tape cartridges have many advantages over other data storage media, notably cost and long-term reliability, but topping the list of drawbacks is their vulnerability to contamination from airborne dust particles; a tiny piece of g...

  6. Sr-Nd-Hf isotopic fingerprinting of transatlantic dust derived from North Africa

    Science.gov (United States)

    Zhao, Wancang; Balsam, William; Williams, Earle; Long, Xiaoyong; Ji, Junfeng

    2018-03-01

    Long-range transport of African dust plays an important role in understanding dust-climate relationships including dust source areas, dust pathways and associated atmospheric and/or oceanic processes. Clay-sized Sr-Nd-Hf isotopic compositions can be used as geochemical fingerprints to constrain dust provenance and the pathways of long-range transported mineral dust. We investigated the clay-sized Sr-Nd-Hf isotopic composition of surface samples along four transects bordering the Sahara Desert. The transects are from Mali, Niger/Benin/Togo, Egypt and Morocco. Our results show that the Mali transect on the West African Craton (WAC) produces lower εNd (εNd-mean = -16.38) and εHf (εHf-mean = -9.59) values than the other three transects. The Egyptian transect exhibits the lowest 87Sr/86Sr ratios (87Sr/86Srmean = 0.709842), the highest εHf (εHf-mean = -0.34) and εNd values of the four transects. Comparison of the clay-sized Sr-Nd-Hf isotopic values from our North African samples to transatlantic African dust collected in Barbados demonstrates that the dust's provenance is primarily the western Sahel and Sahara as well as the central Sahel. Summer emission dust is derived mainly from the western Sahel and Sahara regions. The source of transatlantic dust in spring and autumn is more varied than in the summer and includes dust not only from western areas, but also south central areas. Comparison of the Sr-Nd-Hf isotopic fingerprints between the source and sink of transatlantic dust also suggests that a northwestward shift in dust source occurs from the winter, through the spring and into the summer. The isotopic data we develop here provide another tool for discriminating changes in dust archives resulting from paleoenvironmental evolution of source regions.

  7. Characterization of ice nucleation on different natural dust samples

    Science.gov (United States)

    Kaufmann, Lukas; Hofer, Julian; Marcolli, Claudia; Pinti, Valeria; Hoyle, Christopher; Peter, Thomas

    2014-05-01

    The impact of aerosols on Earth's climate is still uncertain. Therefore a better understanding of direct and indirect effects of aerosols is essential to improve models and the ability to predict future climate change. A natural source of aerosols is desert dust. Laboratory measurements investigating the influence of dust on heterogeneous freezing of water droplets are presented. We performed measurements with seven dust samples collected in the Etosha pan in Namibia, in the Makgadikgadi pan in Botswana (from three different locations), on the Altiplano in Bolivia, in Qatar and in the Hoggar mountains in Algeria. After sieving, the particle diameters of these dusts were < 32 μm. The mineralogical composition of the dusts was determined by X-ray diffraction. For the investigation of the ice nucleation ability of these dusts, emulsion as well as bulk freezing measurements were performed with a differential scanning calorimeter (DSC). For the emulsion measurements a suspension of a dust was mixed with water. Mixed with a mineral oil/lanolin mixture, the water droplets in the emulsion had mean diameters of around 2 μm. Heterogeneous freezing of dusts was characterized by three temperatures for frozen fractions of 0.1, 0.25, and 0.5, respectively. Heterogeneous freezing temperatures for all 7 samples were quite similar, namely 245 - 246.5 K (for frozen fractions of 0.1), 243 - 244.5 K (for 0.25) and 240 - 241.5 K (for 0.5). Emulsions consisting of pure water suspensions froze with onset temperatures of around 237 K. Emulsion measurements with Hoggar mountain dust were also performed with an additional solute such as ammonium sulfate, malonic acid, glucose or PEG 300. Immersion freezing was found to be suppressed in the presence of solutes. For the bulk measurements dusts were suspended in pure water and droplets with radii of about 1 mm were subjected to repeated freezing cycles. Freezing temperatures in the range of 253 - 265 K were found for cooling rates of 10 K

  8. Asteroid/meteorite streams

    Science.gov (United States)

    Drummond, J.

    The independent discovery of the same three streams (named alpha, beta, and gamma) among 139 Earth approaching asteroids and among 89 meteorite producing fireballs presents the possibility of matching specific meteorites to specific asteroids, or at least to asteroids in the same stream and, therefore, presumably of the same composition. Although perhaps of limited practical value, the three meteorites with known orbits are all ordinary chondrites. To identify, in general, the taxonomic type of the parent asteroid, however, would be of great scientific interest since these most abundant meteorite types cannot be unambiguously spectrally matched to an asteroid type. The H5 Pribram meteorite and asteroid 4486 (unclassified) are not part of a stream, but travel in fairly similar orbits. The LL5 Innisfree meteorite is orbitally similar to asteroid 1989DA (unclassified), and both are members of a fourth stream (delta) defined by five meteorite-dropping fireballs and this one asteroid. The H5 Lost City meteorite is orbitally similar to 1980AA (S type), which is a member of stream gamma defined by four asteroids and four fireballs. Another asteroid in this stream is classified as an S type, another is QU, and the fourth is unclassified. This stream suggests that ordinary chondrites should be associated with S (and/or Q) asteroids. Two of the known four V type asteroids belong to another stream, beta, defined by five asteroids and four meteorite-dropping (but unrecovered) fireballs, making it the most probable source of the eucrites. The final stream, alpha, defined by five asteroids and three fireballs is of unknown composition since no meteorites have been recovered and only one asteroid has an ambiguous classification of QRS. If this stream, or any other as yet undiscovered ones, were found to be composed of a more practical material (e.g., water or metalrich), then recovery of the associated meteorites would provide an opportunity for in-hand analysis of a potential

  9. Dust forecasting system in JMA

    International Nuclear Information System (INIS)

    Mikami, M; Tanaka, T Y; Maki, T

    2009-01-01

    JMAs dust forecasting information, which is based on a GCM dust model, is presented through the JMA website coupled with nowcast information. The website was updated recently and JMA and MOE joint 'KOSA' website was open from April 2008. Data assimilation technique will be introduced for improvement of the 'KOSA' information.

  10. Parameterizing the interstellar dust temperature

    NARCIS (Netherlands)

    Hocuk, S.; Szűcs, L.; Caselli, P.; Cazaux, S.; Spaans, M.; Esplugues, G. B.

    2017-01-01

    The temperature of interstellar dust particles is of great importance to astronomers. It plays a crucial role in the thermodynamics of interstellar clouds, because of the gas-dust collisional coupling. It is also a key parameter in astrochemical studies that governs the rate at which molecules form

  11. 75 FR 3881 - Combustible Dust

    Science.gov (United States)

    2010-01-25

    ... Combustible Dust AGENCY: Occupational Safety and Health Administration (OSHA), Labor. ACTION: Notice of stakeholder meetings. SUMMARY: OSHA invites interested parties to participate in informal stakeholder meetings on the workplace hazards of combustible dust. OSHA plans to use the information gathered at these...

  12. 75 FR 10739 - Combustible Dust

    Science.gov (United States)

    2010-03-09

    ... Combustible Dust AGENCY: Occupational Safety and Health Administration (OSHA), Labor. ACTION: Notice of stakeholder meetings. SUMMARY: OSHA invites interested parties to participate in informal stakeholder meetings on the workplace hazards of combustible dust. OSHA plans to use the information gathered at these...

  13. Andromeda's dust

    Energy Technology Data Exchange (ETDEWEB)

    Draine, B. T.; Aniano, G. [Princeton University Observatory, Peyton Hall, Princeton, NJ 08544-1001 (United States); Krause, Oliver; Groves, Brent; Sandstrom, Karin; Klaas, Ulrich; Linz, Hendrik; Rix, Hans-Walter; Schinnerer, Eva; Schmiedeke, Anika; Walter, Fabian [Max-Planck-Institut fur Astronomie, Konigstuhl 17, D-69117 Heidelberg (Germany); Braun, Robert [CSIRO—Astronomy and Space Science, P.O. Box 76, Epping, NWS 1710 (Australia); Leroy, Adam, E-mail: draine@astro.princeton.edu, E-mail: ganiano@ias.u-psud.fr [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States)

    2014-01-10

    Spitzer Space Telescope and Herschel Space Observatory imaging of M31 is used, with a physical dust model, to construct maps of dust surface density, dust-to-gas ratio, starlight heating intensity, and polycyclic aromatic hydrocarbon (PAH) abundance, out to R ≈ 25 kpc. The global dust mass is M {sub d} = 5.4 × 10{sup 7} M {sub ☉}, the global dust/H mass ratio is M {sub d}/M {sub H} = 0.0081, and the global PAH abundance is (q {sub PAH}) = 0.039. The dust surface density has an inner ring at R = 5.6 kpc, a maximum at R = 11.2 kpc, and an outer ring at R ≈ 15.1 kpc. The dust/gas ratio varies from M {sub d}/M {sub H} ≈ 0.026 at the center to ∼0.0027 at R ≈ 25 kpc. From the dust/gas ratio, we estimate the interstellar medium metallicity to vary by a factor ∼10, from Z/Z {sub ☉} ≈ 3 at R = 0 to ∼0.3 at R = 25 kpc. The dust heating rate parameter (U) peaks at the center, with (U) ≈ 35, declining to (U) ≈ 0.25 at R = 20 kpc. Within the central kiloparsec, the starlight heating intensity inferred from the dust modeling is close to what is estimated from the stars in the bulge. The PAH abundance reaches a peak q {sub PAH} ≈ 0.045 at R ≈ 11.2 kpc. When allowance is made for the different spectrum of the bulge stars, q {sub PAH} for the dust in the central kiloparsec is similar to the overall value of q {sub PAH} in the disk. The silicate-graphite-PAH dust model used here is generally able to reproduce the observed dust spectral energy distribution across M31, but overpredicts 500 μm emission at R ≈ 2-6 kpc, suggesting that at R = 2-6 kpc, the dust opacity varies more steeply with frequency (with β ≈ 2.3 between 200 and 600 μm) than in the model.

  14. Dust in flowing magnetized plasma

    International Nuclear Information System (INIS)

    Pandey, Birendra P.; Samarian, Alex A.; Vladimirov, Sergey V.

    2009-01-01

    Plasma flows occur in almost every laboratory device and interactions of flowing plasmas with near-wall impurities and/or dust significantly affects the efficiency and lifetime of such devices. The charged dust inside the magnetized flowing plasma moves primarily under the influence of the plasma drag and electric forces. Here, the charge on the dust, plasma potential, and plasma density are calculated self-consistently. The electrons are assumed non-Boltzmannian and the effect of electron magnetization and electron-atom collisions on the dust charge is calculated in a self-consistent fashion. For various plasma magnetization parameters viz. the ratio of the electron and ion cyclotron frequencies to their respective collision frequencies, plasma-atom and ionization frequencies, the evolution of the plasma potential and density in the flow region is investigated. The variation of the dust charge profile is shown to be a sensitive function of plasma parameters. (author)

  15. Systematic characterization of structural, dynamical and electrical properties of dust devils and implications for dust lifting processes

    Science.gov (United States)

    Franzese, Gabriele; Esposito, Francesca; Lorenz, Ralph D.; Popa, Ciprian; Silvestro, Simone; Deniskina, Natalia; Cozzolino, Fabio

    2017-04-01

    Dust devils are convective vortices able to lift sand and dust grains from the soil surface, even in conditions of low wind speed environment. They have been observed not only on Earth but also on other planets of the solar system; in particular, they are largely studied on Mars. Indeed, the contribution of the dust devils to the Martian climate is a highly debated question. In order to investigate this topic, it is important to understand the nature of the dust lifting mechanism by the vortex and characterize the induced electric field. As part of the development process of DREAMS, the meteorological station on board the Schiapparelli lander of the ExoMars 2016 mission, and of the Dust complex package of the ExoMars 2020 mission, we performed various field campaigns in the Sahara desert (Tafilalt region, Morocco). We deployed a fully equipped meteorological station and, during the 2014 summer, we observed three months of dust devils activity, collecting almost six hundreds events. For each dust devil, we monitored the horizontal wind speed and direction, the vertical wind speed, the pressure drop due to the vortex core, the temperature, the induced electric field and the concentration of dust lifted. This data set is unique in literature and represents up to now the most comprehensive one available for the dusty convective vortices. Here we will present the analysis of the Moroccan data with particular emphasis on the study of the atmospheric electric field variations due to the passage of the vortices. The distribution of the vortex parameters (wind speed and direction, pressure, E-field and dust lifted) are showed and compared, when possible, to the ones observed by the Martian surveys. The connection between the E-field and the other parameters will be presented. In the terrestrial environment, the development of the convective vortices is restricted by the presence of the vegetation and of the urban areas, hence dust devils can impact the climate only on local

  16. Percent Agriculture Adjacent to Streams

    Data.gov (United States)

    U.S. Environmental Protection Agency — The type of vegetation along a stream influences the water quality in the stream. Intact buffer strips of natural vegetation along streams tend to intercept...

  17. Percent Forest Adjacent to Streams

    Data.gov (United States)

    U.S. Environmental Protection Agency — The type of vegetation along a stream influences the water quality in the stream. Intact buffer strips of natural vegetation along streams tend to intercept...

  18. Tank bromeliads capture Saharan dust in El Yunque National Forest, Puerto Rico

    Science.gov (United States)

    Royer, Dana L.; Moynihan, Kylen M.; Ariori, Carolyn; Bodkin, Gavin; Doria, Gabriela; Enright, Katherine; Hatfield-Gardner, Rémy; Kravet, Emma; Nuttle, C. Miller; Shepard, Lisa; Ku, Timothy C. W.; O'Connell, Suzanne; Resor, Phillip G.

    2018-01-01

    Dust from Saharan Africa commonly blows across the Atlantic Ocean and into the Caribbean. Most methods for measuring this dust either are expensive if collected directly from the atmosphere, or depend on very small concentrations that may be chemically altered if collected from soil. Tank bromeliads in the dwarf forest of El Yunque National Forest, Puerto Rico, have a structure of overlapping leaves used to capture rainwater and other atmospheric inputs. Therefore, it is likely that these bromeliads are collecting in their tanks Saharan dust along with local inputs. Here we analyze the elemental chemistry, including rare earth elements (REEs), of tank contents in order to match their chemical fingerprint to a provenance of the Earth's crust. We find that the tank contents differ from the local soils and bedrock and are more similar to published values of Saharan dust. Our study confirms the feasibility of using bromeliad tanks to trace Saharan dust in the Caribbean.

  19. Videos of Basal Ice in Boreholes on the Kamb Ice Stream in West Antarctica, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set is a collection of video data of basal ice taken in a borehole on the Kamb Ice Stream in West Antarctica. Ice streams are an expression of the inherent...

  20. Dust in protoplanetary disks: observations*

    Directory of Open Access Journals (Sweden)

    Waters L.B.F.M.

    2015-01-01

    Full Text Available Solid particles, usually referred to as dust, are a crucial component of interstellar matter and of planet forming disks surrounding young stars. Despite the relatively small mass fraction of ≈1% (in the solar neighborhood of our galaxy; this number may differ substantially in other galaxies that interstellar grains represent of the total mass budget of interstellar matter, dust grains play an important role in the physics and chemistry of interstellar matter. This is because of the opacity dust grains at short (optical, UV wavelengths, and the surface they provide for chemical reactions. In addition, dust grains play a pivotal role in the planet formation process: in the core accretion model of planet formation, the growth of dust grains from the microscopic size range to large, cm-sized or larger grains is the first step in planet formation. Not only the grain size distribution is affected by planet formation. Chemical and physical processes alter the structure and chemical composition of dust grains as they enter the protoplanetary disk and move closer to the forming star. Therefore, a lot can be learned about the way stars and planets are formed by observations of dust in protoplanetary disks. Ideally, one would like to measure the dust mass, the grain size distribution, grain structure (porosity, fluffiness, the chemical composition, and all of these as a function of position in the disk. Fortunately, several observational diagnostics are available to derive constrains on these quantities. In combination with rapidly increasing quality of the data (spatial and spectral resolution, a lot of progress has been made in our understanding of dust evolution in protoplanetary disks. An excellent review of dust evolution in protoplanetary disks can be found in Testi et al. (2014.

  1. Milky Way Dust and Stars in 3D

    Science.gov (United States)

    Green, Gregory; Ford Schlafly, Eddie; Finkbeiner, Douglas P.

    2015-01-01

    We present a three-dimensional map of dust reddening, along with a catalog of stellar distances and properties, determined from Pan-STARRS 1 and 2MASS photometry. Our method uses stars as tracers of the dust column; by inferring distances and reddenings to a billion stars, we determine reddening as a function of distance across three quarters of the sky. Our map has a typical angular resolution of ~7', a distance resolution of ~25%, and saturates at about 1.5 mag in E(B-V). Inferred distances to a large number of clouds agree well with literature distances, and the projected two-dimensional reddening agrees well with maps based on far-infrared dust emission (e.g., SFD '98) away from the Galactic plane. We envision many uses for a 3D map of dust and stars, among them: investigating the structure of the Milky Way and its stellar streams, correctly de-reddening photometry for objects embedded in the plane of the Galaxy, distance determinations to objects of known reddening, and studying the structure of star-forming regions.

  2. Building-related symptoms and inflammatory potency of dust from office buildings

    DEFF Research Database (Denmark)

    Allermann, Leila; Pejtersen, Jan; Gunnarsen, Lars Bo

    2007-01-01

    received a retrospective questionnaire about BRS (2301 respondents). Dust was collected from groups of offices and building characteristics were recorded. The potency of a dust sample to induce interleukin-8 (IL-8) secretion from the lung epithelial cell line A549 was measured as the slope of the initial...

  3. House dust mite exposure in asthmatic and healthy children : The difference is carpeting

    NARCIS (Netherlands)

    vanderHeide, S; Postma, DS; deReus, DM; Koeter, GH; vanAalderen, WMC; Meijer, G.

    1995-01-01

    Aim - To determine whether house dust mite (HDM) exposure in living rooms and bedrooms is higher in asthmatic children than in those of age and sex matched healthy children, living in the same area. Methods - Types of floor-coverings were recorded and dust samples were collected by vacuum cleaning

  4. House dust mite exposure in asthmatic and healthy children: the difference is carpeting

    NARCIS (Netherlands)

    Meijer, G. G.; van der Heide, S.; Postma, D. S.; de Reus, D. M.; Koëter, G. H.; van Aalderen, W. M.

    1995-01-01

    To determine whether house dust mite (HDM) exposure in living rooms and bedrooms is higher in asthmatic children than in those of age and sex matched healthy children, living in the same area. Types of floor-coverings were recorded and dust samples were collected by vacuum cleaning the total area of

  5. Biological effects of desert dust in respiratory epithelial cells and a murine model.

    Science.gov (United States)

    Abstract As a result of the challenge of recent dust storms to public health, we tested the postulate that desert dust collected in the southwestern United States could impact a biological effect in respiratory epithelial cells and an animal model. Two samples of surface sedime...

  6. Characterization of Street Dust Nearby the Holy Mosques in Ramadan and Hajj Seasons, Saudi Arabia

    OpenAIRE

    Abdel Hameed A. A; Ibrahim Y. H; Said Mounir; Habeeballah T; Elmorsy T. H

    2016-01-01

    Street dust is estimated as a main contributor of particualte matter (PM). Resuspension of street dust affects air quality and human health. The present study aims to evaluate concentrations of heavy metals (iron-Fe, lead-Pb, cadmium-Cd, and nickel-Ni), cations (Li+, Na+, NH4+, K+, Mg2+, and Ca2+), anions (F-, Cl-, Br-, NO2-, NO3-, PO43- and SO4-) and microoganisms (bacteria and fungi) associated dust particles ≤ 45 µm. The dust samples were collected by sweeping an arera ~ 1 m2 along both si...

  7. The origin and evolution of dust clouds in Central Asia

    Science.gov (United States)

    Smirnov, V.V.; Gillette, Dale A.; Golitsyn, G.S.; MacKinnon, D.J.

    1994-01-01

    Data from a high resolution radiometer AVHRR (580-680 nm optical lengthwaves) installed on the "NOAA-11" satellite as well as TV (500-700 nm) and IR (8000-12000 nm) equipment of the Russia satellite "Meteor-2/16" were used to study the evolution of dust storms for 1-30 September 1989 in Tajikistan, Uzbekistan, Turkmenistan and Afghanistan. These data help to validate the hypothesis, that long-term dusted boundary layer (duration of the order of a day or more), but of comparatively not high optical density (4-10 km meteorological visibility range at the 20-50 km background), is formed after the northwest intrusions into a region of intensive cold fronts at the surface wind velocities of 7-15 m/s. Stability of dust clouds of vertical power to 3-3.5 km (up to an inversion level) is explained by an action of collective buoyancy factors at heating the dust particles of 2-4 ??m in mean diameter by solar radiation. The more intensive intrusions stimulate a formation of simultaneously dust and water clouds. The last partially reduce the solar radiation (by the calculations of the order of 30-50%) and decrease the role of buoyancy factors. Thus, initiated is the intensive but short-term dusted boundary layer at horizontal visibility of 50-200 m. ?? 1994.

  8. The Stardust Interstellar Dust Collector and Stardust@home

    Science.gov (United States)

    Westphal, A. J.; Anderson, D.; Bastien, R.; Butterworth, A.; Frank, D.; Gainsforth, Z.; Kelley, N.; Lettieri, R.; Mendez, B.; Prasad, R.; Tsitrin, S.; von Korff, J.; Warren, J.; Wertheimer, D.; Zhang, A.; Zolensky, M.

    2006-12-01

    The Stardust sample return mission is effectively two missions in one. Stardust brought back to earth for analytical study the first solid samples from a known solar system body beyond the moon, comet Wild2. The first results of the analyses of these samples are reported elsewhere in this session. In a separate aerogel collector, Stardust also captured and has returned the first samples of contemporary interstellar dust. Landgraf et al. [1] has estimated that ~ 50 interstellar dust particles in the micron size range have been captured in the Stardust Interstellar Dust Collector. Their state after capture is unknown. Before analysis of these particles can begin, they must be located in the collector. Here we describe the current status of Stardust@home, the massively distributed public search for these tiny interstellar dust particles. So far more than 13,000 volunteers have collectively performed more than 10,000,000 searches in stacks of digital images of ~10% of the collector. We report new estimates of the flux of interplanetary dust at ~2 AU based on the results of this search, and will compare with extant models[2]. References: [1] Landgraf et al., (1999) Planet. Spac. Sci. 47, 1029. [2] Staubach et al. (2001) in Interplanetary Dust, E. Grün, ed., Astron. &Astro. Library, Springer, 2001.

  9. Fungi identify the geographic origin of dust samples.

    Science.gov (United States)

    Grantham, Neal S; Reich, Brian J; Pacifici, Krishna; Laber, Eric B; Menninger, Holly L; Henley, Jessica B; Barberán, Albert; Leff, Jonathan W; Fierer, Noah; Dunn, Robert R

    2015-01-01

    There is a long history of archaeologists and forensic scientists using pollen found in a dust sample to identify its geographic origin or history. Such palynological approaches have important limitations as they require time-consuming identification of pollen grains, a priori knowledge of plant species distributions, and a sufficient diversity of pollen types to permit spatial or temporal identification. We demonstrate an alternative approach based on DNA sequencing analyses of the fungal diversity found in dust samples. Using nearly 1,000 dust samples collected from across the continental U.S., our analyses identify up to 40,000 fungal taxa from these samples, many of which exhibit a high degree of geographic endemism. We develop a statistical learning algorithm via discriminant analysis that exploits this geographic endemicity in the fungal diversity to correctly identify samples to within a few hundred kilometers of their geographic origin with high probability. In addition, our statistical approach provides a measure of certainty for each prediction, in contrast with current palynology methods that are almost always based on expert opinion and devoid of statistical inference. Fungal taxa found in dust samples can therefore be used to identify the origin of that dust and, more importantly, we can quantify our degree of certainty that a sample originated in a particular place. This work opens up a new approach to forensic biology that could be used by scientists to identify the origin of dust or soil samples found on objects, clothing, or archaeological artifacts.

  10. Levels of house dust mite allergen in cars.

    Science.gov (United States)

    Mason, Howard J; Smith, Ian; Anua, Siti Marwanis; Tagiyeva, Nargiz; Semple, Sean; Devereux, Graham

    2015-09-01

    This small study investigated house dust mite (HDM) allergen levels in cars and their owners' homes in north-east Scotland. Dust samples from twelve households and cars were collected in a standardised manner. The dust samples were extracted and measured for the Dermatophagoides group 2 allergens (Der p 2 and Der f 2) and total soluble protein. Allergen levels at homes tended to be higher than in the cars, but not significantly. However, they significantly correlated with paired car dust samples expressed either per unit weight of dust or soluble protein (rho=0.657; p=0.02 and 0.769; p=0.003, respectively). This points to house-to-car allergen transfer, with the car allergen levels largely reflecting levels in the owner's home. Car HDM allergen levels were lower than those reported in Brazil and the USA. Twenty-five percent of the houses and none of the cars had allergen levels in dust greater than 2000 ng g(-1). This value is often quoted as a threshold for the risk of sensitisation, although a number of studies report increased risk of sensitisation at lower levels. This small study does not allow for characterisation of the distribution of HDM allergen in vehicles in this geographic area, or of the likely levels in other warmer and more humid areas of the UK. Cars and other vehicles are an under-investigated micro-environment for exposure to allergenic material.

  11. Fungi identify the geographic origin of dust samples.

    Directory of Open Access Journals (Sweden)

    Neal S Grantham

    Full Text Available There is a long history of archaeologists and forensic scientists using pollen found in a dust sample to identify its geographic origin or history. Such palynological approaches have important limitations as they require time-consuming identification of pollen grains, a priori knowledge of plant species distributions, and a sufficient diversity of pollen types to permit spatial or temporal identification. We demonstrate an alternative approach based on DNA sequencing analyses of the fungal diversity found in dust samples. Using nearly 1,000 dust samples collected from across the continental U.S., our analyses identify up to 40,000 fungal taxa from these samples, many of which exhibit a high degree of geographic endemism. We develop a statistical learning algorithm via discriminant analysis that exploits this geographic endemicity in the fungal diversity to correctly identify samples to within a few hundred kilometers of their geographic origin with high probability. In addition, our statistical approach provides a measure of certainty for each prediction, in contrast with current palynology methods that are almost always based on expert opinion and devoid of statistical inference. Fungal taxa found in dust samples can therefore be used to identify the origin of that dust and, more importantly, we can quantify our degree of certainty that a sample originated in a particular place. This work opens up a new approach to forensic biology that could be used by scientists to identify the origin of dust or soil samples found on objects, clothing, or archaeological artifacts.

  12. Treatise of World Trade Center (WTC) Dust generated during the September 2001 terrorist attacks on the WTC towers

    Science.gov (United States)

    Badger, Steven R.

    The initial devastation created by the collapse of the World Trade Center (WTC) Towers resulting from the September 11, 2001 bombings was followed by the dissemination of newly formed toxic dust throughout Lower Manhattan. The ensuing fires that burned within the six-story high debris pile produced a continuous stream of hazardous combustion products. Emphasis on this research was placed on the characterization, the extent of contamination, remediation procedures, and the potential for recontamination by dusts produced by the events of 9/11/2001. A detailed characterization of the WTC Dust was performed using a wide variety of methods. Through the analyses of known WTC Dust, WTC Dust Markers were identified using the composition and morphology of the particles present. Buildings throughout Lower Manhattan were tested for WTC Dust Markers and the radial extent of the WTC Dust was identified. Case studies of buildings located in close proximity to the WTC Site were undertaken to determine the pervasiveness of the WTC Dust into various building systems and components. Testing was conducted on all major building systems/spaces including: occupied spaces, perimeter induction units, structural steel, interior wall cavities, curtain walls, IT raceways, HVAC, and MEP systems. The analytical results indicated that all systems contained WTC Dust and that reservoirs were present. The feasibility of remediation of the WTC Dust from surfaces was evaluated in order to determine if it is possible for the dusts and contaminants to be eradicated. Utilizing standard remediation methods specific to surface type and contaminate type, surfaces throughout the studied buildings were cleaned. Results of post-remediation analyses indicated that remediation efforts in a building contaminated with WTC Dust were ineffective in returning the building to its state prior to the WTC Event. Recontamination studies were also performed in buildings that had been previously cleaned to determine if

  13. Chemistry and Photochemistry at the Surface of Urban Road Dust and Photoactive Minerals

    Science.gov (United States)

    Styler, S. A.; Abou-Ghanem, M.; Wickware, B.

    2017-12-01

    Each year, over a billion tons of dust are released into the atmosphere from arid regions. After its emission, dust can undergo efficient long-range transport to urban centres, where it can interact with local pollution sources. Another source of dust in urban regions is road dust resuspension, which is the largest anthropogenic source of primary particulate matter in both Canada and the United States. Since dust contains light-absorbing components, including iron- and titanium-containing minerals, dust-catalyzed photochemical processes have the potential to influence both the lifetime of pollutants present at the dust surface and the composition of the surrounding atmosphere. To date, most studies of dust photochemistry have focused on TiO2-mediated processes, and no studies have explored trace gas uptake at the surface of road dust. Here, we present first results from aerosol and coated-wall flow tube investigations of ozone uptake at the surface of a suite of titanium-containing minerals and road dust collected in Edmonton, Alberta. Together, this work represents a significant advance in our understanding of chemistry and photochemistry at realistic environmental interfaces.

  14. Influence of dust particles on positive column of DC glow discharge

    Science.gov (United States)

    Tian, Ruihuan; Yuan, Chengxun; Li, Hui; Liang, Yonggan; Wu, Jian; Kudryavtsev, A. A.; Kirsanov, G. V.; Zhou, Zhongxiang; Jiang, Yongyuan

    2018-03-01

    A self-consistent model of a DC glow discharge with dust particles based on orbital motion limited theory, collision enhanced collection approximation, and a fluid approach extended by energy conservation equation is presented. The model indicates the influence of dust particles on radical distributions of plasma parameters in positive columns. Dust particles are embedded in the positive column with the density profile prescribed as a given step function. It is shown that with the increase in dust particle density, electron density and the radical electric field decrease in the dust region. For high dust density, especially when the loss of ions and electrons on the dust surface exceeds their production in ionization collisions in the dust region, a local minimum of electron density forms in the discharge axis and the radical electric field obtained from the Poisson equation becomes non-monotonous. The addition of dust increases the longitudinal electric field and electron temperature simultaneously to compensate the electron and ion loss on dust particles and preserve the discharge.

  15. Academic streaming in Europe

    DEFF Research Database (Denmark)

    Falaschi, Alessandro; Mønster, Dan; Doležal, Ivan

    2004-01-01

    The TF-NETCAST task force was active from March 2003 to March 2004, and during this time the mem- bers worked on various aspects of streaming media related to the ultimate goal of setting up common services and infrastructures to enable netcasting of high quality content to the academic community...... in Europe. We report on a survey of the use of streaming media in the academic community in Europe, an open source content delivery network, and a portal for announcing live streaming events to the global academic community....

  16. Wadeable Streams Assessment Data

    Science.gov (United States)

    The Wadeable Streams Assessment (WSA) is a first-ever statistically-valid survey of the biological condition of small streams throughout the U.S. The U.S. Environmental Protection Agency (EPA) worked with the states to conduct the assessment in 2004-2005. Data for each parameter sampled in the Wadeable Streams Assessment (WSA) are available for downloading in a series of files as comma separated values (*.csv). Each *.csv data file has a companion text file (*.txt) that lists a dataset label and individual descriptions for each variable. Users should view the *.txt files first to help guide their understanding and use of the data.

  17. Migration of tungsten dust in tokamaks: role of dust–wall collisions

    International Nuclear Information System (INIS)

    Ratynskaia, S.; Vignitchouk, L.; Tolias, P.; Bykov, I.; Bergsåker, H.; Litnovsky, A.; Den Harder, N.; Lazzaro, E.

    2013-01-01

    The modelling of a controlled tungsten dust injection experiment in TEXTOR by the dust dynamics code MIGRAINe is reported. The code, in addition to the standard dust–plasma interaction processes, also encompasses major mechanical aspects of dust–surface collisions. The use of analytical expressions for the restitution coefficients as functions of the dust radius and impact velocity allows us to account for the sticking and rebound phenomena that define which parts of the dust size distribution can migrate efficiently. The experiment provided unambiguous evidence of long-distance dust migration; artificially introduced tungsten dust particles were collected 120° toroidally away from the injection point, but also a selectivity in the permissible size of transported grains was observed. The main experimental results are reproduced by modelling. (paper)

  18. Carpet-dust chemicals as measures of exposure: Implications of variability

    Directory of Open Access Journals (Sweden)

    Whitehead Todd P

    2012-03-01

    Full Text Available Abstract Background There is increasing interest in using chemicals measured in carpet dust as indicators of chemical exposures. However, investigators have rarely sampled dust repeatedly from the same households and therefore little is known about the variability of chemical levels that exist within and between households in dust samples. Results We analyzed 9 polycyclic aromatic hydrocarbons, 6 polychlorinated biphenyls, and nicotine in 68 carpet-dust samples from 21 households in agricultural communities of Fresno County, California collected from 2003-2005. Chemical concentrations (ng per g dust ranged from Conclusions Our findings suggest that attenuation bias should be relatively modest when using these semi-volatile carpet-dust chemicals as exposure surrogates in epidemiologic studies.

  19. Pyrophoric sulfides influence over the minimum ignition temperature of dust cloud

    Science.gov (United States)

    Prodan, Maria; Lupu, Leonard Andrei; Ghicioi, Emilian; Nalboc, Irina; Szollosi-Mota, Andrei

    2017-12-01

    The dust cloud is the main form of existence of combustible dust in the production area and together with the existence of effective ignition sources are the main causes of dust explosions in production processes. The minimum ignition temperature has an important role in the process of selecting the explosion-protected electrical equipment when performing the explosion risk assessment of combustible dusts. The heated surfaces are able to ignite the dust clouds that can form in process industry. The oil products usually contain hydrogen sulfide and thus on the pipe walls iron sulfides can form, which can be very dangerous from health and safety point of view. In order to study the influence of the pyrophoric sulfide over the minimum ignition temperature of combustible dusts for this work were performed several experiments on a residue collected from the oil pipes contaminated with commercially iron sulfide.

  20. Quartz measurement in coal dust with high-flow rate samplers: laboratory study.

    Science.gov (United States)

    Lee, Taekhee; Lee, Eun Gyung; Kim, Seung Won; Chisholm, William P; Kashon, Michael; Harper, Martin

    2012-05-01

    A laboratory study was performed to measure quartz in coal dust using high-flow rate samplers (CIP10-R, GK2.69 cyclone, and FSP10 cyclone) and low-flow rate samplers [10-mm nylon and Higgins-Dewell type (BGI4L) cyclones] and to determine whether an increased mass collection from high-flow rate samplers would affect the subsequent quartz measurement by Fourier transform infrared (FTIR) and X-ray diffraction (XRD) analytical procedures. Two different sizes of coal dusts, mass median aerodynamic diameter 4.48 μm (Coal Dust A) and 2.33 μm (Coal Dust B), were aerosolized in a calm air chamber. The mass of coal dust collected by the samplers was measured gravimetrically, while the mass of quartz collected by the samplers was determined by FTIR (NIOSH Manual of Analytical Method 7603) and XRD (NIOSH Manual of Analytical Method 7500) after one of two different indirect preparations. Comparisons between high-flow rate samplers and low-flow rate samplers were made by calculating mass concentration ratios of coal dusts, net mass ratios of coal dusts, and quartz net mass. Mass concentrations of coal dust from the FSP10 cyclone were significantly higher than those from other samplers and mass concentrations of coal dust from 10-mm nylon cyclone were significantly lower than those from other samplers, while the CIP10-R, GK2.69, and BGI4L samplers did not show significant difference in the comparison of mass concentration of coal dusts. The BGI4L cyclone showed larger mass concentration of ∼9% compared to the 10-mm nylon cyclone. All cyclones provided dust mass concentrations that can be used in complying with the International Standard Organization standard for the determination of respirable dust concentration. The amount of coal dust collected from the high-flow rate samplers was found to be higher with a factor of 2-8 compared to the low-flow rate samplers but not in direct proportion of increased flow rates. The high-flow rate samplers collected more quartz compared to

  1. COLLIDING DECIMETER DUST

    Energy Technology Data Exchange (ETDEWEB)

    Deckers, J.; Teiser, J., E-mail: johannes.deckers@uni-due.de [Fakultaet fuer Physik, Universitaet Duisburg-Essen, D-47057 Duisburg (Germany)

    2013-06-01

    Collisional evolution is a key process in planetesimal formation and decimeter bodies play a key role in the different models. However, the outcome of collisions between two dusty decimeter bodies has never been studied experimentally. Therefore, we carried out microgravity collision experiments in the Bremen drop tower. The agglomerates consist of quartz with irregularly shaped micrometer-sized grains and the mean volume filling factor is 0.437 {+-} 0.004. The aggregates are cylindrical with 12 cm in height and 12 cm in diameter, and typical masses are 1.5 kg. These are the largest and most massive dust aggregates studied in collisions to date. We observed rebound and fragmentation but no sticking in the velocity range between 0.8 and 25.7 cm s{sup -1}. The critical fragmentation velocity for split up of an aggregate is 16.2 {+-} 0.4 cm s{sup -1}. At lower velocities the aggregates bounce off each other. In this velocity range, the coefficient of restitution decreases with increasing collision velocity from 0.8 to 0.3. While the aggregates are very weak, the critical specific kinetic energy for fragmentation Q{sub {mu}=1} is a factor of six larger than expected. Collisions of large bodies in protoplanetary disks are supposed to be much faster and the generation of smaller fragments is likely. In planetary rings, collision velocities are of the order of a few cm s{sup -1} and are thereby in the same range investigated in these experiments. The coefficient of restitution of dust agglomerates and regolith-covered ice particles, which are common in planetary rings, are similar.

  2. Dust Around T Tauri Stars

    Directory of Open Access Journals (Sweden)

    Kyung-Won Suh

    2011-12-01

    Full Text Available To reproduce the multiple broad peaks and the fine spectral features in the spectral energy distributions (SEDs of T Tauri stars, we model dust around T Tauri stars using a radiative transfer model for multiple isothermal circumstellar dust shells. We calculate the radiative transfer model SEDs for multiple dust shells using the opacity functions for various dust grains at different temperatures. For six sample stars, we compare the model results with the observed SEDs including the Spitzer spectral data. We present model parameters for the best fit model SEDs that would be helpful to understand the overall structure of dust envelopes around classical T Tauri stars. We find that at least three separate dust components are required to reproduce the observed SEDs. For all the sample stars, an innermost hot (250-550 K dust component of amorphous (silicate and carbon and crystalline (corundum for all objects and forsterite for some objects grains is needed. Crystalline forsterite grains can reproduce many fine spectral features of the sample stars. We find that crystalline forsterite grains exist in cold regions (80-100 K as well as in hot inner shells.

  3. Geochemical investigation of dry- and wet-deposited dust during the same dust-storm event in Harbin, China: Constraint on provenance and implications for formation of aeolian loess

    Science.gov (United States)

    Xie, Yuanyun; Chi, Yunping

    2016-04-01

    A strong dust-storm event occurred in Harbin, China on May 11, 2011. The dry- and wet-deposited dust depositions in this dust-storm event, together with the surface sediments from the potential sources, were collected to study grain size distributions, carbonate content and carbon isotopic composition of carbonate, major element, trace element and rare earth elements (REE), and Sr-Nd isotopic compositions. The results indicate as follows. The dry-deposited dusts are characterized by bimodal grain-size distributions with a fine mode at 3.6 μm and a coarse mode at 28 μm whereas the wet-deposited dusts are indicative of unimodal grain-size modes with a fine mode at 6 μm. The dust-storm depositions are influenced to a certain extent by sedimentary sorting and are of a derivation from the recycled sediments. Based on identifying the immobility of element pairs before constraining sources of dust-storm deposits using geochemical elements, in conjunction with REE and especially Sr-Nd isotopic compositions, the primary and strengthening sources for the dust-storm event were detected, respectively. The Hunsandake Sandy Land as the primary source and the Horqin Sandy Land as the strengthening source were together responsible for the derivation of dust depositions during dust-storm event. The Hunsandake Sandy Land, however, contributes less dust to the dust-storm event in Harbin compared to the Horqin Sandy Land, and the Hulun Buir Sandy Land is undoubtedly excluded from being one of the sources for dust-storm depositions in Harbin. There are not notable differences in geochemical (especially Sr-Nd isotopic) compositions between dry- and wet-deposited dusts, indicating that the wet-deposited dust is of identical derivation to the dry-deposited dust. Based on our observations, it is of interest to suggest that fine and coarse particles in the CLP (Chinese Loess Plateau) loess possibly have the same sources.

  4. The development of a HEPA filter with improved dust holding characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Dyment, J.; Hamblin, C.

    1995-02-01

    A limitation of the HEPA filters used in the extract of nuclear facilities is their relatively low capacity for captured dust. The costs associated with the disposal of a typical filter means that there are clear incentives to extend filter life. The work described in this report are the initial stages in the development of a filter which incorporates a medium which enhances its dust holding capacity. Experimental equipment was installed to enable the dust loading characteristics of candidate media to be compared with those of the glass fibre based papers currently used in filter construction. These tests involved challenging representative samples of the media with an air stream containing a controlled concentration of thermally generated sodium chloride particles. The dust loading characteristics of the media were then compared in terms of the rate of increasing in pressure differential. A number of {open_quotes}graded density{close_quotes} papers were subsequently identified which appeared to offer significant improvements in dust holding. In the second phase of the programme deep-pleat filters (1,700 M{sup 3}h{sup {minus}1}) incorporating graded density papers were manufactured and tested. Improvements of up to 50% were observed in their capacity for the sub-micron sodium chloride test dust. Smaller differences (15%) were measured when a coarser, carbon black, challenge was used. This is attributed to the differences in the particles sizes of the two dusts.

  5. Methodological details of determining maximum single concentration of dust along scraper longwalls of coal mines

    Energy Technology Data Exchange (ETDEWEB)

    Rubanov, G.P.; Grebtsov, E.M.; Kurnosov, V.K.; Tolstoi, G.I.

    1988-06-01

    Recommendations of 'Instructions on determining pneumoconiosis danger of mine work in coal mines' for choice of a basic point for measuring maximum single concentration of dust along scraper longwalls do not make it possible to objectively evaluate dust load at working places. In the Instructions, a point at 10 to 15 m from exit of longwall on the ventilation drift with an emergent stream of air is proposed for the dust probe. This designated point does not take into account the influence of the scheme of ventilation of the walls on formation of dust currents. Investigations of probes taken at different places along the longwall (at the beginning, 15 m from the begining, 15 m from the end, at the niche and transfer point of the longwal) using direct and reverse flow schemes of ventilation showed that the best point for determining maximum single concentratin of dust is a point in the middle of the longwall where dust currents are the same for both systems of ventilation, and use of a new method of calculating the dust load by testing at many different positions along the scraper longall makes it possible to determine the category of pneumonoconiosis danger for workers at scraper longwalls.

  6. The development of a HEPA filter with improved dust holding characteristics

    International Nuclear Information System (INIS)

    Dyment, J.; Hamblin, C.

    1995-01-01

    A limitation of the HEPA filters used in the extract of nuclear facilities is their relatively low capacity for captured dust. The costs associated with the disposal of a typical filter means that there are clear incentives to extend filter life. The work described in this report are the initial stages in the development of a filter which incorporates a medium which enhances its dust holding capacity. Experimental equipment was installed to enable the dust loading characteristics of candidate media to be compared with those of the glass fibre based papers currently used in filter construction. These tests involved challenging representative samples of the media with an air stream containing a controlled concentration of thermally generated sodium chloride particles. The dust loading characteristics of the media were then compared in terms of the rate of increasing in pressure differential. A number of open-quotes graded densityclose quotes papers were subsequently identified which appeared to offer significant improvements in dust holding. In the second phase of the programme deep-pleat filters (1,700 M 3 h -1 ) incorporating graded density papers were manufactured and tested. Improvements of up to 50% were observed in their capacity for the sub-micron sodium chloride test dust. Smaller differences (15%) were measured when a coarser, carbon black, challenge was used. This is attributed to the differences in the particles sizes of the two dusts

  7. Numerical Simulation of the Direct Radiative Effects of Dust Aerosol on the East Asian Winter Monsoon

    Directory of Open Access Journals (Sweden)

    Hui Sun

    2015-01-01

    Full Text Available Variations of the East Asian winter monsoon (EAWM induced by dust aerosol are studied by using a regional climate model (RegCM4/Dust. Dust coupled and uncoupled experiments are carried out for the past decade (2000–2009. The coupled RegCM4 captures three centers of dust mixing ratio (DMR located in the Taklamakan Desert, western Inner Mongolia, and northern Xinjiang, respectively, with maximum values greater than 500 µg kg−1 in winter. The surface total radiation change induced by dust is negative, and its central value of −8 W m−2 results in surface temperature cooling by 1.5°C in winter. Dust induced radiation change at the top of the atmosphere (TOA is also negative in Northern China, except over the Tibetan Plateau (TP, and up to −5 W m−2 in Central China. Dust cooling effects increase the sea level pressure (SLP gradient between land and ocean, the cold surge frequency, and the East Asian jet stream (EAJ intensity and then enhance the EAWM. The dry and cold wind pervade most areas of East Asia, suppressing large-scale precipitation and eventually leading to a rainfall decrease of about 10–30% in Northern China and the middle Yangtze River Valley.

  8. Risk of Adverse Health and Performance Effects of Celestial Dust Exposure

    Science.gov (United States)

    Scully, Robert R.; Meyers, Valerie E.

    2015-01-01

    Crew members can be directly exposed to celestial dust in several ways. After crew members perform extravehicular activities (EVAs), they may introduce into the habitat dust that will have collected on spacesuits and boots. Cleaning of the suits between EVAs and changing of the Environmental Control Life Support System filters are other operations that could result in direct exposure to celestial dusts. In addition, if the spacesuits used in exploration missions abrade the skin, as current EVA suits have, then contact with these wounds would provide a source of exposure. Further, if celestial dusts gain access to a suit's interior, as was the case during the Apollo missions, the dust could serve as an additional source of abrasions or enhance suit-induced injuries. When a crew leaves the surface of a celestial body and returns to microgravity, the dust that is introduced into the return vehicle will "float," thus increasing the opportunity for ocular and respiratory injury. Because the features of the respirable fraction of lunar dusts indicate they could be toxic to humans, NASA conducted several studies utilizing lunar dust simulants and authentic lunar dust to determine the unique properties of lunar dust that affect physiology, assess the dermal and ocular irritancy of the dust, and establish a permissible exposure limit for episodic exposure to airborne lunar dust during missions that would involve no more than 6 months stay on the lunar surface. Studies, with authentic lunar soils from both highland (Apollo 16) and mare (Apollo17) regions demonstrated that the lunar soil is highly abrasive to a high fidelity model of human skin. Studies of lunar dust returned during the Apollo 14 mission from an area of the moon in which the soils were comprised of mineral constituents from both major geological regions (highlands and mares regions) demonstrated only minimal ocular irritancy, and pulmonary toxicity that was less than the highly toxic terrestrial crystalline

  9. Acoustic streaming in microchannels

    DEFF Research Database (Denmark)

    Tribler, Peter Muller

    This thesis presents studies of boundary-driven acoustic streaming in microfluidic channels, which is a steady flow of the fluid initiated by the interactions of an oscillating acoustic standing wave and the rigid walls of the microchannel. The studies present analysis of the acoustic resonance......, the acoustic streaming flow, and the forces on suspended microparticles. The work is motivated by the application of particle focusing by acoustic radiation forces in medical, environmental and food sciences. Here acoustic streaming is most often unwanted, because it limits the focusability of particles...... oscillating plates. Furthermore, under general thermodynamic conditions, we derive the time-dependent first- and second-order equations for the conservation of mass, momentum, and energy. The coupling from fluid equations to particle motion is achieved through the expressions for the streaming-induced drag...

  10. Streaming tearing mode

    Science.gov (United States)

    Shigeta, M.; Sato, T.; Dasgupta, B.

    1985-01-01

    The magnetohydrodynamic stability of streaming tearing mode is investigated numerically. A bulk plasma flow parallel to the antiparallel magnetic field lines and localized in the neutral sheet excites a streaming tearing mode more strongly than the usual tearing mode, particularly for the wavelength of the order of the neutral sheet width (or smaller), which is stable for the usual tearing mode. Interestingly, examination of the eigenfunctions of the velocity perturbation and the magnetic field perturbation indicates that the streaming tearing mode carries more energy in terms of the kinetic energy rather than the magnetic energy. This suggests that the streaming tearing mode instability can be a more feasible mechanism of plasma acceleration than the usual tearing mode instability.

  11. Stochastic ice stream dynamics.

    Science.gov (United States)

    Mantelli, Elisa; Bertagni, Matteo Bernard; Ridolfi, Luca

    2016-08-09

    Ice streams are narrow corridors of fast-flowing ice that constitute the arterial drainage network of ice sheets. Therefore, changes in ice stream flow are key to understanding paleoclimate, sea level changes, and rapid disintegration of ice sheets during deglaciation. The dynamics of ice flow are tightly coupled to the climate system through atmospheric temperature and snow recharge, which are known exhibit stochastic variability. Here we focus on the interplay between stochastic climate forcing and ice stream temporal dynamics. Our work demonstrates that realistic climate fluctuations are able to (i) induce the coexistence of dynamic behaviors that would be incompatible in a purely deterministic system and (ii) drive ice stream flow away from the regime expected in a steady climate. We conclude that environmental noise appears to be crucial to interpreting the past behavior of ice sheets, as well as to predicting their future evolution.

  12. Future Roads Near Streams

    Data.gov (United States)

    U.S. Environmental Protection Agency — Roads are a source of auto related pollutants (e.g. gasoline, oil and other engine fluids). When roads are near streams, rain can wash these pollutants directly into...

  13. Roads Near Streams

    Data.gov (United States)

    U.S. Environmental Protection Agency — Roads are a source of auto related pollutants (e.g. gasoline, oil and other engine fluids). When roads are near streams, rain can wash these pollutants directly into...

  14. Trout Stream Special Regulations

    Data.gov (United States)

    Minnesota Department of Natural Resources — This layer shows Minnesota trout streams that have a special regulation as described in the 2006 Minnesota Fishing Regulations. Road crossings were determined using...

  15. DNR 24K Streams

    Data.gov (United States)

    Minnesota Department of Natural Resources — 1:24,000 scale streams captured from USGS seven and one-half minute quadrangle maps, with perennial vs. intermittent classification, and connectivity through lakes,...

  16. Scientific stream pollution analysis

    National Research Council Canada - National Science Library

    Nemerow, Nelson Leonard

    1974-01-01

    A comprehensive description of the analysis of water pollution that presents a careful balance of the biological,hydrological, chemical and mathematical concepts involved in the evaluation of stream...

  17. Determinants, reproducibility, and seasonal variation of ergosterol levels in house dust.

    Science.gov (United States)

    Leppänen, H K; Nevalainen, A; Vepsäläinen, A; Roponen, M; Täubel, M; Laine, O; Rantakokko, P; von Mutius, E; Pekkanen, J; Hyvärinen, A

    2014-06-01

    This study aimed to clarify the determinants that affect the concentrations of ergosterol and viable fungi in house dust and to examine the seasonal variation and reproducibility of ergosterol concentrations indoors. In studying the determinants, dust samples from living room floors and vacuum cleaner dust bags were collected from 107 farming and 105 non-farming homes. Ergosterol levels were determined with gas chromatography-mass spectrometry,and the dust bag dust was cultivated for enumeration of fungal genera. Lifestyle and environmental factors, for example using of the fireplace, and visible mold observations in homes, explained 20–26% of the variation of fungal concentrations. For the reproducibility study, samples were collected from five urban homes in four different seasons. The reproducibility of ergosterol determinations within a sample was excellent (ICC = 89.8) for floor dust and moderate (ICC = 63.8) for dust bag dust, but poor when sampling the same home throughout a year (ICC = 31.3 and 12.6, respectively) due to large temporal variation in ergosterol concentrations. In conclusion, environmental characteristics only partially predicted the variation of fungal concentrations. Based on these studies, we recommend repeated sampling of dust over time if one seeks to adequately describe overall fungal levels and exposure in a home. This study shows that levels of ergosterol and viable fungi in house dust are related to visible mold observations. Only 20% of the variation in fungal levels can be explained with questionnaires, and therefore, environmental samples need to be taken in addition. Reproducibility of ergosterol determination was excellent for floor dust, and thus, ergosterol measurements from floor dust samples could be suitable for assessing the fungal load in building investigations. The temporal variation needs to be taken into account when describing the ergosterol concentration of urban homes.

  18. Estimate of safe human exposure levels for lunar dust based on comparative benchmark dose modeling.

    Science.gov (United States)

    James, John T; Lam, Chiu-Wing; Santana, Patricia A; Scully, Robert R

    2013-04-01

    Brief exposures of Apollo astronauts to lunar dust occasionally elicited upper respiratory irritation; however, no limits were ever set for prolonged exposure to lunar dust. The United States and other space faring nations intend to return to the moon for extensive exploration within a few decades. In the meantime, habitats for that exploration, whether mobile or fixed, must be designed to limit human exposure to lunar dust to safe levels. Herein we estimate safe exposure limits for lunar dust collected during the Apollo 14 mission. We instilled three respirable-sized (∼2 μ mass median diameter) lunar dusts (two ground and one unground) and two standard dusts of widely different toxicities (quartz and TiO₂) into the respiratory system of rats. Rats in groups of six were given 0, 1, 2.5 or 7.5 mg of the test dust in a saline-Survanta® vehicle, and biochemical and cellular biomarkers of toxicity in lung lavage fluid were assayed 1 week and one month after instillation. By comparing the dose--response curves of sensitive biomarkers, we estimated safe exposure levels for astronauts and concluded that unground lunar dust and dust ground by two different methods were not toxicologically distinguishable. The safe exposure estimates were 1.3 ± 0.4 mg/m³ (jet-milled dust), 1.0 ± 0.5 mg/m³ (ball-milled dust) and 0.9 ± 0.3 mg/m³ (unground, natural dust). We estimate that 0.5-1 mg/m³ of lunar dust is safe for periodic human exposures during long stays in habitats on the lunar surface.

  19. Atmospheric dust events in central Asia: Relationship to wind, soil type, and land use

    Science.gov (United States)

    Pi, Huawei; Sharratt, Brenton; Lei, Jiaqiang

    2017-06-01

    Xinjiang Province in northwest China is one of the most important source regions of atmospheric dust in the world. Spatial-temporal characteristics of dust events in the province were investigated by time series analysis of annual dust event frequency and meteorological data collected at 101 meteorological stations from 1960 to 2007. Blowing dust frequency (BDF) and dust storm frequency (DSF) decreased with time in North, South, and East Xinjiang whereas floating dust frequency (FDF) decreased with time only in South and East Xinjiang. Dust concentrations were lower in North than in South Xinjiang and decreased with time in East Xinjiang. Wind significantly influenced the temporal trend in FDF, BDF, and DSF in South Xinjiang and DSF in North Xinjiang. Frequency of dust events was smaller by an order of magnitude in North (10.9 d yr-1) than in South Xinjiang (111.3 d yr-1), possibly due in part to higher annual precipitation in North Xinjiang. Floating dust was most frequently observed in East and South Xinjiang, while blowing dust was most frequently observed in North Xinjiang. The high frequency of floating dust in East and South Xinjiang is likely due to the enclosed terrain that characterizes these regions. Land use and soil type also influenced dust events. Although climate influences frequency of dust events, the occurrence of these events may be reduced most effectively by imposing better land management practices in deciduous forests or orchards characterized by saline soils in respectively North and East Xinjiang and meadows characterized by Guanyu soils in South Xinjiang.

  20. Photoelectric Charging of Dust Particles in Vacuum

    International Nuclear Information System (INIS)

    Sickafoose, A. A.; Colwell, J. E.; Horanyi, M.; Robertson, S.

    2000-01-01

    Photoelectric charging measurements are presented of dust grains in vacuum for isolated grains and for grains near a photoemissive surface. Isolated grains reach a positive-equilibrium floating potential, dependent upon the work function of the particle, which causes the emitted electrons to be returned. Grains dropped past a photoemitting surface reach a negative floating potential for which the sum of the emitted and collected currents is zero. The particles tested are 90-106 μm in diameter and are composed of Zn, Cu, graphite, and glass. (c) 2000 The American Physical Society

  1. Polycyclic aromatic hydrocarbons profile of kitchen dusts.

    Science.gov (United States)

    Iwegbue, Chukwujindu M A

    2011-03-01

    Concentrations and profiles of polycyclic aromatic hydrocarbons (PAHs) were determined in thirty dust samples collected from kitchens that use wood cook system (WCS), kerosene stove cook system (KSCS) and butane gas cook system (BGCS). The total PAHs concentrations ranged from 52 to 497, 39 to 96 and 37 to 155 μg kg(-1) for WCS, KSCS and BGCS respectively. The results indicate predominance of lower molecular weight (2-3 rings) over higher molecular weight PAHs and users of wood cook system are more exposed to higher levels of PAHs than the users of either kerosene cook system or butane gas cook system.

  2. Nonextensive electron and ion dust charging currents

    International Nuclear Information System (INIS)

    Amour, Rabia; Tribeche, Mouloud

    2011-01-01

    The correct nonextensive electron and ion charging currents are presented for the first time based on the orbit motion limited approach. For -1< q<1, where q measures the amount of plasma nonextensivity, the nonextensive electron charging current is expressed in terms of the hypergeometric function. The variable dust charge is expressed in terms of the Lambert function and we take advantage of this transcendental function to investigate succinctly the effects of nonextensive charge carriers. The obtained formulas bring a possibility to build theories on nonlinear collective process in variable charge nonextensive dusty plasmas.

  3. Triton's streaks as windblown dust

    Science.gov (United States)

    Sagan, Carl; Chyba, Christopher

    1990-01-01

    Explanations for the surface streaks observed by Voyager 2 on Triton's southern hemisphere are discussed. It is shown that, despite Triton's tenuous atmosphere, low-cohesion dust trains with diameters of about 5 micron or less may be carried into suspension by aeolian surface shear stress, given expected geostrophic wind speeds of about 10 m/s. For geyser-like erupting dust plumes, it is shown that dust-settling time scales and expected wind velocities can produce streaks with length scales in good agreement with those of the streaks. Thus, both geyserlike eruptions or direct lifting by surface winds appear to be viable mechanisms for the origin of the streaks.

  4. Cascading Norwegian co-streams for bioeconomic transition

    DEFF Research Database (Denmark)

    Egelyng, Henrik; Romsdal, A.; Hansen, Henning Otte

    2018-01-01

    uses of co-streams: automation and scanning technologies for fractioning raw materials and co-streams into different qualities, a collection system for fish rest raw materials at sea, enzymatic hydrolysis, use of second grade vegetables for smoothies and potato peels for biodegradable plastics...

  5. The terrestrial invertebrate fauna of a temporary stream in southern ...

    African Journals Online (AJOL)

    The terrestrial invertebrate fauna of an intermittent stream was examined in the absence of surface flows within the context of the flood pulse concept. Terrestrial invertebrates were collected from three sites on the Kruis River in theWestern Cape Province, South Africa, using pitfall traps within the dry stream bed over ...

  6. AMIDST: Analysis of MassIve Data STreams

    DEFF Research Database (Denmark)

    Masegosa, Andres; Martinez, Ana Maria; Borchani, Hanen

    2015-01-01

    The Analysis of MassIve Data STreams (AMIDST) Java toolbox provides a collection of scalable and parallel algorithms for inference and learning of hybrid Bayesian networks from data streams. The toolbox, available at http://amidst.github.io/toolbox/ under the Apache Software License version 2...

  7. Collaborative Media Streaming

    OpenAIRE

    Kahmann, Verena

    2008-01-01

    Mit Hilfe der IP-Technologie erbrachte Multimedia-Dienste wie IPTV oder Video-on-Demand sind zur Zeit ein gefragtes Thema. Technisch werden solche Dienste unter dem Begriff "Streaming" eingeordnet. Ein Server sendet Mediendaten kontinuierlich an Empfänger, welche die Daten sofort weiterverarbeiten und anzeigen. Über einen Rückkanal hat der Kunde die Möglichkeit der Einflussnahme auf die Wiedergabe. Eine Weiterentwicklung dieser Streaming-Dienste ist die Möglichkeit, gemeinsam mit anderen dens...

  8. Android Video Streaming

    Science.gov (United States)

    2014-05-01

    ad hoc network established between devices that are in range of each other. 15. SUBJECT TERMS Android, video, streaming, ad hoc 16. SECURITY ...Android PowerManager wake lock settings. Flag Value CPU Screen Keyboard PARTIAL_WAKE_LOCK Ona Off Off SCREEN_DIM_WAKE_LOCK On Dim Off... stock ROM and modifying it as described in Mobile Ad-Hoc Networking on Android Devices (15) allowed the video streaming to work properly over an ad hoc

  9. Solar wind stream evolution

    International Nuclear Information System (INIS)

    Gosling, J.T.

    1978-01-01

    Highlights of the recent progress in understanding the problem of high speed stream evolution with increasing heliocentric distance are reviewed. Crucial to this understanding are the measurements made in the inner solar system by Helios and the outer solar system by Pioneers 10 and 11. When coupled with observations at 1 AU these measurements allow a testing of current theoretical models of stream evolution. 21 references

  10. Development of the isotopic analysis of individual macroparticles: a study of desert dust and interplanetary dust

    International Nuclear Information System (INIS)

    Aleon, Jerome

    2001-01-01

    During this thesis a new analytical technique has been developed to allow the determination of isotopic ratios in microparticles. This technique is based on the imaging properties of the IMS 1270 ion microprobe in CRPG in Nancy. The development of quantitative isotopic imaging allows the determination of the 18 O/ 16 O ratio of individual macroparticles having a size < 2 μm with a 3 to 4 % precision and to map, with ∼ 1 μm lateral resolution, the isotopic variation of hydrogen in particles having a size of 10 μm. This new technique was used to study the problem of the origin of Saharan dust particles, indeed the distribution of 18 O/ 16 O ratios in individual quartz grains is shown to be a characteristic fingerprint of the geology of the source area. The determination of oxygen isotopic ratio in individual grains of a given dust storm above the Atlantic Ocean indicates that the likely source area of this storm is the Air-Tenere region. This result has strong implications for the cycle of Saharan dust in the atmosphere and the processes of dust suspension into the atmosphere. Mapping the D/H variations in 4 interplanetary dust particles collected in the stratosphere by the NASA shows that these particles contain several distinct types of organic matter having an interstellar origin. These organic matters can be related to polymers measured in cornets and carbonaceous chondrites. The presence of these different polymers inside one single particle suggests that the most primitive materials of the solar system may be related to each other. (author) [fr

  11. Streaming Pool: reuse, combine and create reactive streams with pleasure

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    When connecting together heterogeneous and complex systems, it is not easy to exchange data between components. Streams of data are successfully used in industry in order to overcome this problem, especially in the case of "live" data. Streams are a specialization of the Observer design pattern and they provide asynchronous and non-blocking data flow. The ongoing effort of the ReactiveX initiative is one example that demonstrates how demanding this technology is even for big companies. Bridging the discrepancies of different technologies with common interfaces is already done by the Reactive Streams initiative and, in the JVM world, via reactive-streams-jvm interfaces. Streaming Pool is a framework for providing and discovering reactive streams. Through the mechanism of dependency injection provided by the Spring Framework, Streaming Pool provides a so called Discovery Service. This object can discover and chain streams of data that are technologically agnostic, through the use of Stream IDs. The stream to ...

  12. Microbial incorporation of nitrogen in stream detritus

    Science.gov (United States)

    Diane M. Sanzone; Jennifer L. Tank; Judy L. Meyer; Patrick J. Mulholland; Stuart E.G. Findlay

    2001-01-01

    We adapted the chloroform fumigation method to determine microbial nitrogen (N) and microbial incorporation of 15N on three common substrates [leaves, wood and fine benthic organic matter (FBOM)] in three forest streams. We compared microbial N and 15 content of samples collected during a 6-week15N-NH...

  13. Stream Side Science Lesson Plan: Missing Macroinvertebrates

    OpenAIRE

    Mesner, Nancy

    2014-01-01

    In this exercise, students will collect macroinvertebrates from a stream site, sort and identify them, and use their fi ndings to identify current and past impacts to the quality of the water. They will also make predictions of how the impacts to the water quality contributed to the localized extinction of some types of macroinvertebrates.

  14. Macroinvertebrates as Indicators of Stream Health.

    Science.gov (United States)

    McDonald, Brook S.; And Others

    1991-01-01

    Describes Ohio's Scenic Rivers Monitoring Program that uses benthic macroinvertebrates, such as the stonefly, mayfly, and water penny beetle larva, as key indicators of water quality and stream health. Presents a three-category scheme for invertebrates based upon their tolerance to pollution. Students can collect samples of these organisms,…

  15. 30 CFR 75.402 - Rock dusting.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Rock dusting. 75.402 Section 75.402 Mineral... SAFETY STANDARDS-UNDERGROUND COAL MINES Combustible Materials and Rock Dusting § 75.402 Rock dusting... or too high in incombustible content to propagate an explosion, shall be rock dusted to within 40...

  16. PERSPECTIVE: Dust, fertilization and sources

    Science.gov (United States)

    Remer, Lorraine A.

    2006-11-01

    Aerosols, tiny suspended particles in the atmosphere, play an important role in modifying the Earth's energy balance and are essential for the formation of cloud droplets. Suspended dust particles lifted from the world's arid regions by strong winds contain essential minerals that can be transported great distances and deposited into the ocean or on other continents where productivity is limited by lack of usable minerals [1]. Dust can transport pathogens as well as minerals great distance, contributing to the spread of human and agricultural diseases, and a portion of dust can be attributed to human activity suggesting that dust radiative effects should be included in estimates of anthropogenic climate forcing. The greenish and brownish tints in figure 1 show the wide extent of monthly mean mineral dust transport, as viewed by the MODerate resolution Imaging Spectroradiometer (MODIS) satellite sensor. The monthly mean global aerosol system for February 2006 from the MODIS aboard the Terra satellite Figure 1. The monthly mean global aerosol system for February 2006 from the MODIS aboard the Terra satellite. The brighter the color, the greater the aerosol loading. Red and reddish tints indicate aerosol dominated by small particles created primarily from combustion processes. Green and brownish tints indicate larger particles created from wind-driven processes, usually transported desert dust. Note the bright green band at the southern edge of the Saharan desert, the reddish band it must cross if transported to the southwest and the long brownish transport path as it crosses the Atlantic to South America. Image courtesy of the NASA Earth Observatory (http://earthobservatory.nasa.gov). Even though qualitatively we recognize the extent and importance of dust transport and the role that it plays in fertilizing nutrient-limited regions, there is much that is still unknown. We are just now beginning to quantify the amount of dust that exits one continental region and the

  17. Monitoring Saharan dust from source to sink: from Iwik [Mauritania] to Statia [Caribbean

    Science.gov (United States)

    van Hateren, Hans; van der Does, Michelle; Friese, Carmen; Korte, Laura; Munday, Chris; Stuut, Jan-Berend

    2015-04-01

    The particle-size distribution and composition of mineral dust is often used as a tool to reconstruct palaeo-environmental conditions in the source(s) of the dust. In on-land (loess), lacustrine, and marine archives, the size of dust deposits is considered a proxy for paleo-wind intensity. However, next to wind strength, the particle size of aeolian deposits is also influenced by various other parameters such as source-to-sink distance, altitude at which the particles have been transported, and various environmental conditions in the sources of the dust. To verify if we can quantify a relationship between the size and composition of mineral dust particles and prevailing environmental conditions, we study "modern" dust. Within three ongoing projects, funded by the Dutch NWO, German DFG, and the ERC, we are studying dust collected on land in Mauritania (Iwik, in the Parc National de Banc d'Arguin, sampling on a monthly resolution) with an array of marine sediment-traps (five moorings at 12°N across the Atlantic Ocean with two sediment traps each between 23° and 57°W, sampling on a 2-weekly resolution) as well as automated mineral-dust collection at sea (on dust-collecting buoys at 12°N/38°W and 12°N/49°W, sampling on a 2-weekly resolution), and finally with a high-volume dust collector on St Eustatius (17°N/63°W, sampling on a 2-weekly resolution). Here we compare initial results of the particle-size distributions of the "minimally-disturbed" fraction of the on-land dust collectors with the terrigenous sediment fraction from the sediment traps, and discuss temporal and spatial trends.

  18. Streams and their future inhabitants

    DEFF Research Database (Denmark)

    Sand-Jensen, K.; Friberg, N.

    2006-01-01

    In this fi nal chapter we look ahead and address four questions: How do we improve stream management? What are the likely developments in the biological quality of streams? In which areas is knowledge on stream ecology insuffi cient? What can streams offer children of today and adults of tomorrow?...

  19. Elemental Concentration of Harmattan Dust Sample in Iwo and Oyo ...

    African Journals Online (AJOL)

    ADOWIE PERE

    ABSTRACT: The period of Harmattan season in Nigeria occurs between the month November and March, this is characterized by dry and dusty north easterly trade wind which blows from the Sahara Desert over Nigeria. Samples of the dust were collected at Iwo (7º 63'N, 4º 19'E) and Oyo (8º 12'N, 3º 42'E). The samples ...

  20. speciation of heavy metals in street dust samples from sakarya

    African Journals Online (AJOL)

    Preferred Customer

    20 dust samples collected from the streets of the Organized Industrial District in Sakarya, Turkey using sequential extraction procedure ... of heavy metals in environmental and biological samples involve highly sensitive spectroscopic techniques [26] ... Mn, Ni, Pb and Zn) were used in the preparation of calibration solutions.

  1. Laser-induced mobilization of dust produced during fusion reactors operation

    International Nuclear Information System (INIS)

    Vatry, A.

    2010-01-01

    During tokamak operation, plasma-wall interactions lead to material erosion process and dusts production. These dusts are mainly composed by carbon and tungsten, with sizes ranging from 10 nm to 100 μm. For safety reasons and to guarantee an optimum reactor functioning, the dusts have to be kept in reasonable quantity. The dusts mobilization is a first step to collect them, and the laser is a promising technique for this application. To optimize the cleaning, physical mechanisms responsible for dust ejection induced by laser have been identified. Some particles, such as aggregates, are directly ablated by the laser. The metal droplets are ejected intact by an electrostatic force, induced by the photoelectrons. We also characterized the particles ejection to choose an appropriate collection device. (author) [fr

  2. Regarding Electrified Martian Dust Storms

    Science.gov (United States)

    Farrell, W. M.

    2017-06-01

    We examine the dynamic competition between dust devil/storm charging currents and dissipating atmospheric currents. A question: Can high-current lightning be a dissipation product of this competition? Most likely not but there are exceptions.

  3. Loess and Eolian Dust Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Records of past environment derived from Loess and Eolian dust (silt-sized material deposited on the Earth surface by the surface winds. Parameter keywords describe...

  4. Understanding mineral dusts from the Middle East

    Science.gov (United States)

    Engelbrecht, J. P.; McDonald, E.; Gillies, J. A.; Jayanty, J.; Casuccio, G.; Gertler, A.

    2012-12-01

    The purpose of the program was to provide scientifically founded information on the chemical and physical properties of airborne mineral dust collected during a period of approximately one year, largely in 2006, at Djibouti, Afghanistan (Bagram, Khowst), Qatar, United Arab Emirates, Iraq (Balad, Baghdad, Tallil, Tikrit, Taji, Al Asad), and Kuwait (Northern, Central, Coastal, and Southern regions). To fully understand mineral dusts, their chemical and physical properties as well as mineralogical interrelationships were accurately established. Three collocated low volume particulate samplers, one each for the total suspended (TSP), less than 10 μm in aerodynamic diameter (PM10), and less than 2.5 μm in aerodynamic diameter (PM2.5) particulate matter were deployed at each of the 15 sites, operating on a "1 in 6 day" sampling schedule. A total of 3,136 filter samples were collected on a 1-in-6 day schedule, along with one-time bulk soil samples, at each of the 15 sites. Sample media included Teflon® membrane and quartz fiber filters for chemical analysis (71 species), and Nuclepore® filters for individual particle analysis by Scanning Electron Microscopy (SEM). The provisional study of the data revealed three broad air pollution sources: geological dust, smoke from burn pits, and until now unidentified lead-zinc smelters and battery-processing facilities. SEM results and secondary electron imagery show that quartz and other silicate minerals and, to a lesser extent, dolomite and calcite particles are coated by a thin Si-Al-Mg layer, probably the clay minerals palygorskite and/or montmorillonite/illite. Positive Matrix Factorization (PMF) was performed on aerosol samples collected at six military sites in Iraq (Balad, Baghdad, Tallil, Tikrit, Taji, and Al Asad). PMF results reflect chemical differences amongst sources impacting at individual sites, further complicated by the regional geomorphology and meteorology. Sampling sites are seldom impacted by one source at

  5. Dust Availability in Desert Terrains

    Science.gov (United States)

    1985-01-01

    RAVIKOVIrCIl, 1953: KAPLAN , 19119. Si ATKINE. 1960). From Yaalon & Ginzhourg (1988). B.8 AMOUNTS AND CONCENTRATIONS OFl DUST IN THE ATMOSPHERE (see also...deposits of comparable origin and age further north along the Dead Sea Rift. Another exampie is the lava flows of latest Pleisto- cene age in the Cima ...the Cima Volcanic Field in the southern Mojave Desert, located downwind of extensive dust-producing playa surfaces. More than 1 m of a gravel-free B

  6. Elemental analyses of modern dust in southern Nevada and California

    Science.gov (United States)

    Reheis, M.C.; Budahn, J.R.; Lamothe, P.J.

    1999-01-01

    Selected samples of modern dust collected in marble traps at sites in southern Nevada and California (Reheis and Kihl, 1995; Reheis, 1997) have been analyzed for elemental composition using instrumental neutron activation analysis (INAA) and inductively coupled plasma atomic emission spectroscopy (ICP-AES) and inductively coupled plasma mass spectroscopy (ICP-MS). For information on these analytical techniques and their levels of precision and accuracy, refer to Baedecker and McKown (1987) for INAA, to Briggs (1996) for ICP-AES, and to Briggs and Meier (1999) for ICP-MS. This report presents the elemental compositions obtained using these techniques on dust samples collected from 1991 through 1997.The dust-trap sites were established at varying times; some have been maintained since 1984, others since 1991. For details on site location, dust-trap construction, and collection techniques, see Reheis and Kihl (1995) and Reheis (1997). Briefly, the trap consists of a coated angel-food cake pan painted black on the outside and mounted on a post about 2 m above the ground. Glass marbles rest on a circular piece of galvanized hardware cloth (now replaced by stainless-steel mesh), which is fitted into the pan so that it rests 3-4 cm below the rim. The 2-m height eliminates most saltating sand-sized particles. The marbles simulate the effect of a gravelly fan surface and prevent dust that has filtered or washed into the bottom of the pan from being blown back out. The dust traps are fitted with two metal straps looped in an inverted basket shape; the top surfaces of the straps are coated with a sticky material that effectively discourages birds from roosting.

  7. Investigating A Novel Flame Retardant Known as V6: Measurements in Baby Products, House Dust and Car Dust

    Science.gov (United States)

    Fang, Mingliang; Webster, Thomas F.; Gooden, David; Cooper, Ellen M.; McClean, Michael D.; Carignan, Courtney; Makey, Colleen; Stapleton, Heather M.

    2013-01-01

    With the phase-out of polybrominated diphenyl ether (PBDE) flame retardants, the use of new and alternate flame retardants has been increasing. 2,2-bis(chloromethyl)propane-1,3-diyltetrakis(2-chloroethyl) bisphosphate, known as V6, is a flame retardant applied to polyurethane foam commonly found in furniture and automobile foam. However, to the authors’ knowledge, no research has been conducted on V6 levels in the environment. The intention of this study was to measure the concentration of V6 in foam collected from baby products where it was recently detected, and measure levels in dust samples collected from homes and automobiles in the Boston, MA area. To accomplish this a pure V6 commercial standard was purchased from a Chinese manufacturer and purified (> 98%). An analytical method to measure V6 in dust samples using liquid chromatography tandem mass spectrometry (LC/MS-MS) was developed. Extraction was conducted using Accelerated Solvent Extraction (ASE) and extracts were purified using an ENVI-Florisil SPE column (500 mg, 3mL). V6 was measured in foam samples collected from baby products with a concentration ranging from 24,500,000 to 59,500,000 ng/g of foam (n = 12, average ± sd: 46,500,000 ± 12,000,000 ng/g; i.e., on average, 4.6 % of the foam mass was V6). V6 was also detected in 19 of 20 car dust samples and 14 of 20 house dust samples analyzed. The concentration of V6 in the house dust ranged from car dust with a median of 103.0 ng/g. Concentrations in car dust were significantly higher than the house dust, potentially indicating higher use of V6 in automobiles compared to products found in the home. Furthermore, tris (2-chloroethyl) phosphate (TCEP), a known carcinogen, was found in the V6 commercial mixture (14% by weight) as an impurity and was consistently detected with V6 in the foam samples analyzed. A significant correlation was also observed between V6 and TCEP in the dust samples, suggesting that the use of V6 is a significant source of TCEP

  8. Environmental controls of wood entrapment in upper Midwestern streams

    Science.gov (United States)

    Merten, Eric C.; Finlay, Jacques; Johnson, Lucinda; Newman, Raymond; Stefan, Heinz; Vondracek, Bruce C.

    2011-01-01

    Wood deposited in streams provides a wide variety of ecosystem functions, including enhancing habitat for key species in stream food webs, increasing geomorphic and hydraulic heterogeneity and retaining organic matter. Given the strong role that wood plays in streams, factors that influence wood inputs, retention and transport are critical to stream ecology. Wood entrapment, the process of wood coming to rest after being swept downstream at least 10 m, is poorly understood, yet important for predicting stream function and success of restoration efforts. Data on entrapment were collected for a wide range of natural wood pieces (n = 344), stream geomorphology and hydraulic conditions in nine streams along the north shore of Lake Superior in Minnesota. Locations of pieces were determined in summer 2007 and again following an overbank stormflow event in fall 2007. The ratio of piece length to effective stream width (length ratio) and the weight of the piece were important in a multiple logistic regression model that explained 25% of the variance in wood entrapment. Entrapment remains difficult to predict in natural streams, and often may simply occur wherever wood pieces are located when high water recedes. However, this study can inform stream modifications to discourage entrapment at road crossings or other infrastructure by applying the model formula to estimate the effective width required to pass particular wood pieces. Conversely, these results could also be used to determine conditions (e.g. pre-existing large, stable pieces) that encourage entrapment where wood is valued for ecological functions.

  9. Suspended dust in Norwegian cities

    International Nuclear Information System (INIS)

    2001-01-01

    According to calculations, at least 80 000 people in Oslo and 8 000 in Trondheim were annoyed by too much suspended dust in 2000. The dust concentration is greatest in the spring, presumably because dust is swirling up from melting snow and ice on the streets. Car traffic is the main source of the dust, except for some of the most highly exposed regions where wood-firing from old stoves contributes up to 70 percent of the dust. National targets for air quality include suspended dust, nitrogen dioxide, sulphur dioxide and benzene. Calculations show that nitrogen dioxide emissions exceeding the limit affected 4 000 people in Oslo and 1 000 people in Trondheim. The sulphur dioxide emissions in the major cities did non exceed the national quality limit; they did exceed the limit in some of the smaller industrial centres. In Trondheim, measurements show that the national limit for benzene was exceeded. Most of the emission of nitrogen dioxide comes from the road traffic. Local air pollution at times causes considerable health- and well-being problems in the larger cities and industrial centres, where a great part of the population may be at risk of early death, infection of the respiratory passage, heart- and lung diseases and cancer

  10. [Distribution characteristics and influencing factors of children with allergic rhinitis in a domestic dust mites allergens content distribution characteristics and influencing factors].

    Science.gov (United States)

    Ji, Dong; Gui, Xiaozhong; Jiang, Wanjin; Wang, Qin

    2015-03-01

    To observe the household environment dust mites allergens content distribution characteristics and influence factors of children with allergic rhinitis to dust mites in Wuhu. Collect the surface dust in bedroom and living room floor, mattresses, pillows, sofa of 102 children with allergic rhinitis families. Dust mite allergen components 1 (Der f1) and house dust mites allergens 1 components (Der p1) of the dust samples were determined by enzyme-linked immunosorbent assay (ELISA). One hundred and twenty samples were collected . In a domestic dust mites samples, with a median of M (Min and Max) said dust mite allergen levels, Der f1 and Der p1 content was 2.66 (0.03, 26.63), 3.48 (0, 03, 33.68), respectively. Der f1 was significantly less than Der p1, and the difference was statistically significant (P dust mites content of urban was significantly more than that of villages and towns, the difference was statistically significant (P dust mites allergens content in either boy's or girl's family were similar, there was no statistically significant difference (P > 0.05). The household dust mites of children allergic rhinitisin Wuhu area is given priority to with Der p1, and urban dust mites are significantly more than village's and town's. Enhancing health education, controlling dust mites allergens contamination inside the bedroom, especially urban areas, are positive differences for the prevention and treatment of allergic diseases such as allergic rhinitis in children.

  11. Stream structure at low flow: biogeochemical patterns in intermittent streams over space and time

    Science.gov (United States)

    MacNeille, R. B.; Lohse, K. A.; Godsey, S.; McCorkle, E. P.; Parsons, S.; Baxter, C.

    2017-12-01

    Climate change in the western United States is projected to lead to earlier snowmelt, increasing fire risk and potentially transitioning perennial streams to intermittent ones. Differences between perennial and intermittent streams, especially the temporal and spatial patterns of carbon and nutrient dynamics during periods of drying, are understudied. We examined spatial and temporal patterns in surface water biogeochemistry during a dry (2016) and a wet (2017) water year in southwest Idaho. We hypothesized that as streams dry, carbon concentrations would increase due to evapoconcentration and/or increased in-stream production, and that the heterogeneity of constituents within each stream would increase. We expected these patterns to differ in a high water year compared to a low water year due to algae scour. Finally, we expected that the spatial heterogeneity of biogeochemistry would decrease with time following fire. To test these hypotheses, in 2016 we collected surface water samples at 50 meter intervals from two intermittent headwater streams over 2,500 meter reaches in April, May, and June. One stream is burned and one remains unburned. In 2017, we collected surface water at the 50, 25 and 10 meter intervals from each stream once during low flow. 2016 results showed average concentrations of dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC) increased 3-fold from April to June in the burned site compared to the unburned site. Interestingly, average concentrations of total nitrogen (TN) dropped substantially for the burned site over these three months, but only decreased slightly for the unburned site over the same time period. Between wet and dry water years, we observed a decrease in the spatial heterogeneity as measured by the standard deviation (SD) in conductivity at 50 meter intervals; the burned stream had a SD of 23.08 in 2016 and 11.40 in 2017 whereas the unburned stream had similar SDs. We conclude that the burned stream experienced

  12. Towards the Development of a Low Cost Airborne Sensing System to Monitor Dust Particles after Blasting at Open-Pit Mine Sites.

    Science.gov (United States)

    Alvarado, Miguel; Gonzalez, Felipe; Fletcher, Andrew; Doshi, Ashray

    2015-08-12

    Blasting is an integral part of large-scale open cut mining that often occurs in close proximity to population centers and often results in the emission of particulate material and gases potentially hazardous to health. Current air quality monitoring methods rely on limited numbers of fixed sampling locations to validate a complex fluid environment and collect sufficient data to confirm model effectiveness. This paper describes the development of a methodology to address the need of a more precise approach that is capable of characterizing blasting plumes in near-real time. The integration of the system required the modification and integration of an opto-electrical dust sensor, SHARP GP2Y10, into a small fixed-wing and multi-rotor copter, resulting in the collection of data streamed during flight. The paper also describes the calibration of the optical sensor with an industry grade dust-monitoring device, Dusttrak 8520, demonstrating a high correlation between them, with correlation coefficients (R(2)) greater than 0.9. The laboratory and field tests demonstrate the feasibility of coupling the sensor with the UAVs. However, further work must be done in the areas of sensor selection and calibration as well as flight planning.

  13. Towards the Development of a Low Cost Airborne Sensing System to Monitor Dust Particles after Blasting at Open-Pit Mine Sites

    Directory of Open Access Journals (Sweden)

    Miguel Alvarado

    2015-08-01

    Full Text Available Blasting is an integral part of large-scale open cut mining that often occurs in close proximity to population centers and often results in the emission of particulate material and gases potentially hazardous to health. Current air quality monitoring methods rely on limited numbers of fixed sampling locations to validate a complex fluid environment and collect sufficient data to confirm model effectiveness. This paper describes the development of a methodology to address the need of a more precise approach that is capable of characterizing blasting plumes in near-real time. The integration of the system required the modification and integration of an opto-electrical dust sensor, SHARP GP2Y10, into a small fixed-wing and multi-rotor copter, resulting in the collection of data streamed during flight. The paper also describes the calibration of the optical sensor with an industry grade dust-monitoring device, Dusttrak 8520, demonstrating a high correlation between them, with correlation coefficients (R2 greater than 0.9. The laboratory and field tests demonstrate the feasibility of coupling the sensor with the UAVs. However, further work must be done in the areas of sensor selection and calibration as well as flight planning.

  14. STARDUST C/E/L DUST FLUX MONITOR INSTRUMENT-2-EDR-V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — Data collected by the Dust Flux Monitor Instrument (DFMI) of the Stardust satellite, taken during the early cruise phase of the mission. These data were determined...

  15. Dust Count Observations March 1933 - August 1933 in College-Fairbanks, AK, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — These data are daily dust count observations taken in College-Fairbanks, Alaska from 23 March 1933 to 29 August 1933. The data are part of a larger collection titled...

  16. Dust Count Observations March 1933 - August 1933 in College-Fairbanks, AK

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are daily dust count observations taken in College-Fairbanks, Alaska from 23 March 1933 to 29 August 1933. The data are part of a larger collection titled...

  17. Speciation of heavy metals in street dust samples from Sakarya I ...

    African Journals Online (AJOL)

    , Pb and Zn) in 20 dust samples collected from the streets of the Organized Industrial District in Sakarya, Turkey using sequential extraction procedure were determined by ICP-OES. The three-step BCR sequential extraction procedure was ...

  18. Dust emissions from unpaved roads on the Colorado Plateau

    Science.gov (United States)

    Duniway, M.; Flagg, C.; Belnap, J.

    2013-12-01

    On the Colorado Plateau, elevated levels of aeolian dust have become a major land management and policy concern due to its influence on climate, weather, terrestrial ecosystem dynamics, landscape development and fertility, melting of snow and ice, air quality, and human health. Most desert soil surfaces are stabilized by plants, rocks, and/or physical or biological soil crusts, but once disturbed, sediment production from these surfaces can increase dramatically. Road development and use is a common surface disturbing activity in the region. The extent and density of roads and road networks is rapidly increasing due to continued energy exploration, infrastructure development, and off-highway recreation activities. Though it is well known that unpaved roads produce dust, the relative contribution of dust from existing roads or the implications of future road development to regional dust loading is unknown. To address this need, we have initiated a multifaceted research effort to evaluating dust emissions from unpaved roads regionally. At 34 sites arranged across various road surfaces and soil textures in southeastern Utah, we are: 1) monitoring dust emissions, local wind conditions, and vehicle traffic and 2) evaluating fugitive dust potential using a portable wind tunnel and measuring road characteristics that affect dust production. We will then 3) develop a GIS-based model that integrates results from 1 & 2 to estimate potential dust contributions from current and future scenarios of regional road development. Passive, horizontal sediment traps were installed at three distances downwind from the road edge. One control trap was placed upwind of the samplers to account for local, non-road dust emissions. An electronic vehicle counter and anemometer were also installed at monitoring sites. Dust samples were collected every three months at fixed heights, 15 cm up to 100 cm above the soil surface, from March 2010 to the present. Threshold friction velocities (TFV

  19. Pulmonary and Systemic Immune Response to Chronic Lunar Dust Inhalation

    Science.gov (United States)

    Crucian, Brian; Quiriarte, Heather; Nelman, Mayra; Lam, Chiu-wing; James, John T.; Sams, Clarence

    2014-01-01

    Background: Due to millennia of meteorite impact with virtually no erosive effects, the surface of the Moon is covered by a layer of ultra-fine, reactive Lunar dust. Very little is known regarding the toxicity of Lunar dust on human physiology. Given the size and electrostatic characteristics of Lunar dust, countermeasures to ensure non-exposure of astronauts will be difficult. To ensure astronaut safety during any future prolonged Lunar missions, it is necessary to establish the effect of chronic pulmonary Lunar dust exposure on all physiological systems. Methods: This study assessed the toxicity of airborne lunar dust exposure in rats on pulmonary and system immune system parameters. Rats were exposed to 0, 20.8, or 60.8 mg/m3 of lunar dust (6h/d; 5d/wk) for up to 13 weeks. Sacrifices occurred after exposure durations of 1day, 7 days, 4 weeks and 13 weeks post-exposure, when both blood and lung lavage fluid were collected for analysis. Lavage and blood assays included leukocyte distribution by flow cytometry, electron/fluorescent microscopy, and cytokine concentration. Cytokine production profiles following mitogenic stimulation were performed on whole blood only. Results: Untreated lavage fluid was comprised primarily of pulmonary macrophages. Lunar dust inhalation resulted in an influx of neutrophils and lymphocytes. Although the percentage of lymphocytes increased, the T cell CD4:CD8 ratio was unchanged. Cytokine analysis of the lavage fluid showed increased levels of IL-1b and TNFa. These alterations generally persisted through the 13 week sampling. Blood analysis showed few systemic effects from the lunar dust inhalation. By week 4, the peripheral granulocyte percentage was elevated in the treated rats. Plasma cytokine levels were unchanged in all treated rats compared to controls. Peripheral blood analysis showed an increased granulocyte percentage and altered cytokine production profiles consisting of increased in IL-1b and IL-6, and decreased IL-2

  20. Heavy Metal Distribution in Street Dust from Traditional Markets and the Human Health Implications.

    Science.gov (United States)

    Kim, Jin Ah; Park, Jin Hee; Hwang, Won Ju

    2016-08-13

    Street dust is a hazard for workers in traditional markets. Exposure time is longer than for other people, making them vulnerable to heavy metals in street dust. This study investigated heavy metal concentrations in street dust samples collected from different types of markets. It compared the results with heavy metal concentrations in heavy traffic and rural areas. Street dust was significantly enriched with most heavy metals in a heavy traffic area while street dust from a fish market was contaminated with cupper (Cu), lead (Pb) and zinc (Zn). Street dust from medicinal herb and fruit markets, and rural areas were not contaminated. Principal component and cluster analyses indicated heavy metals in heavy traffic road and fish market dust had different sources. Relatively high heavy metal concentration in street dust from the fish market may negatively affect worker's mental health, as depression levels were higher compared with workers in other markets. Therefore, intensive investigation of the relationship between heavy metal concentrations in street dust and worker's health in traditional marketplaces should be conducted to elucidate the effect of heavy metals on psychological health in humans.

  1. Heavy Metal Distribution in Street Dust from Traditional Markets and the Human Health Implications

    Directory of Open Access Journals (Sweden)

    Jin Ah Kim

    2016-08-01

    Full Text Available Street dust is a hazard for workers in traditional markets. Exposure time is longer than for other people, making them vulnerable to heavy metals in street dust. This study investigated heavy metal concentrations in street dust samples collected from different types of markets. It compared the results with heavy metal concentrations in heavy traffic and rural areas. Street dust was significantly enriched with most heavy metals in a heavy traffic area while street dust from a fish market was contaminated with cupper (Cu, lead (Pb and zinc (Zn. Street dust from medicinal herb and fruit markets, and rural areas were not contaminated. Principal component and cluster analyses indicated heavy metals in heavy traffic road and fish market dust had different sources. Relatively high heavy metal concentration in street dust from the fish market may negatively affect worker’s mental health, as depression levels were higher compared with workers in other markets. Therefore, intensive investigation of the relationship between heavy metal concentrations in street dust and worker’s health in traditional marketplaces should be conducted to elucidate the effect of heavy metals on psychological health in humans.

  2. Investigation of sulfate and nitrate formation on mineral dust particles by receptor modeling

    Energy Technology Data Exchange (ETDEWEB)

    Hien, P.D.; Bac, V.T.; Thinh, N.T.H. [Vietnam Atomic Energy Commission, Hanoi (Vietnam)

    2005-12-01

    The formation of sulfate and nitrate by heterogeneous reactions of gaseous precursors on mineral dust particles was investigated using positive matrix factorization (PMF) of coarse PM10 (particulate diameters from 2.2 to 10 {mu} m) collected at urban (Hanoi) and rural (Lucnam) sites in northern Vietnam. Air samples were analyzed for ionic and elemental components using ion chromatography and proton induced X-ray emission methods. PMF revealed six similar sources/types of coarse PM10 at the two sites, namely soil dust containing nitrate and sulfate, coal fly ash from distant and local sources, soil dust containing organic matter and ammonium sulfate and marine aerosol. Traffic (road) dust was found only at the urban site. From the PMF factor models, the yields of NO{sub 3}{sup -}, SO{sub 4}{sup 2-} and NH{sub 4}{sup +} can be estimated and their possible chemical forms in different particulate types can be suggested. The yields of nitrate and sulfate formation on mineral dust particles increase with the (Ca)/(Si) ratio, which is greater in soil dust than in coal fly ash. Nitrate is bound to Ca-richest soil dust particles. Ammonium was found in dust particles containing soil organic matter, which also hold the largest amount of sulfate. The comparison of urban and rural receptor models provided synergy for the source identification and insights into the properties of mineral dust particles relevant to their interactions with acidic gases in ambient air.

  3. Evaluation of the Corrosivity of Dust Deposited on Waste Packages at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    C. Bryan; R. Jarek; T. Wolery; D. Shields; M. Sutton; E. Hardin; D. Barr

    2005-01-01

    Small amounts of dust will be deposited on the surfaces of waste packages in drifts at Yucca Mountain during the operational and the preclosure ventilation periods. Salts present in the dust will deliquesce as the waste packages cool and relative humidity in the drifts increases. In this paper, we evaluate the potential for brines formed by dust deliquescence to initiate and sustain localized corrosion that results in failure of the waste package outer barrier and early failure of the waste package. These arguments have been used to show that dust deliquescence-induced localized or crevice corrosion of the waste package outer barrier (Alloy 22) is of low consequence with respect to repository performance. Measured atmospheric and underground dust compositions are the basis of thermodynamic modeling and experimental studies to evaluate the likelihood of brine formation and persistence, the volume of brines that may form, and the relative corrosivity of the initial deliquescent brines and of brines modified by processes on the waste package surface. In addition, we evaluate several mechanisms that could inhibit or stifle localized corrosion should it initiate. The dust compositions considered include both tunnel dust samples from Yucca Mountain, National Airfall Deposition Program rainout data, and collected windblown dust samples. Also considered is sublimation of ammonium salts, a process that could affect dust composition prior to deliquescence. Ammonium chlorides, nitrates, and even sulfates sublimate readily into ammonia and acid gases, and will be lost from the surface of the waste package prior to deliquescence

  4. Evaluation of the presence of house dust mites in horse rugs.

    Science.gov (United States)

    Wallace, Jessica C; Vogelnest, Linda J

    2010-12-01

    A sample of fourteen horse rugs and two saddle blankets stored in south western Sydney, Australia, an area of known high dust mite prevalence in the human environment, were analysed for the presence of house dust mites. Dust samples from the rugs, blankets and 16 control sites were collected using a vacuum cleaner with a modified attachment and filter. Dust mites were extracted using an adapted floatation technique. Eight rugs and all control samples were positive for mites, which were confirmed to be house dust mites of the genus Dermatophagoides. This study confirms that exposure to house dust mites from horse rugs can occur, indicating that house dust mite allergen reactivity on intradermal and serum allergy testing in atopic horses may represent true dust mite hypersensitivity. Nevertheless, quantification studies will be necessary to ensure that there is adequate mite exposure for development of hypersensitivity, and further evaluation of immunological responses, avoidance and provocation, and specific immunotherapy are required to confirm the clinical relevance. To the authors' knowledge, this is the first study to document the presence of house dust mites in the equine environment. © 2010 The Authors. Journal compilation © 2010 ESVD and ACVD.

  5. Secondary charging effects due to icy dust particle impacts on rocket payloads

    Science.gov (United States)

    Kassa, M.; Rapp, M.; Hartquist, T. W.; Havnes, O.

    2012-03-01

    We report measurements of dust currents obtained with a small probe and a larger probe during the flight of the ECOMA-4 rocket through the summer polar mesosphere. The payload included two small dust probes behind a larger dust probe located centrally at the front. For certain phases of the payload rotation, the current registered by one of the small dust probes was up to 2 times the current measured with the larger probe, even though the effective collection area of the larger probe was 4 times that of the small one. We analyze the phase dependence of the currents and their difference with a model based on the assumption that the small probe was hit by charged dust fragments produced in collisions of mesospheric dust with the payload body. Our results confirm earlier findings that secondary charge production in the collision of a noctilucent cloud/Polar Summer Mesospheric Echo (NLC/PMSE) dust particle with the payload body must be several orders of magnitude larger than might be expected from laboratory studies of collisions of pure ice particles with a variety of clean surfaces. An important consequence is that for some payload configurations, one should not assume that the current measured with a detector used to study mesospheric dust is simply proportional to the number density of ambient dust particles. The higher secondary charge production may be due to the NLC/PMSE particles containing multiple meteoric smoke particles.

  6. Secondary charging effects due to icy dust particle impacts on rocket payloads

    Directory of Open Access Journals (Sweden)

    M. Kassa

    2012-03-01

    Full Text Available We report measurements of dust currents obtained with a small probe and a larger probe during the flight of the ECOMA-4 rocket through the summer polar mesosphere. The payload included two small dust probes behind a larger dust probe located centrally at the front. For certain phases of the payload rotation, the current registered by one of the small dust probes was up to 2 times the current measured with the larger probe, even though the effective collection area of the larger probe was 4 times that of the small one. We analyze the phase dependence of the currents and their difference with a model based on the assumption that the small probe was hit by charged dust fragments produced in collisions of mesospheric dust with the payload body. Our results confirm earlier findings that secondary charge production in the collision of a noctilucent cloud/Polar Summer Mesospheric Echo (NLC/PMSE dust particle with the payload body must be several orders of magnitude larger than might be expected from laboratory studies of collisions of pure ice particles with a variety of clean surfaces. An important consequence is that for some payload configurations, one should not assume that the current measured with a detector used to study mesospheric dust is simply proportional to the number density of ambient dust particles. The higher secondary charge production may be due to the NLC/PMSE particles containing multiple meteoric smoke particles.

  7. Dust Particle Size Distributions during Spring in Yinchuan, China

    OpenAIRE

    Jiangfeng Shao; Jiandong Mao

    2016-01-01

    Dust particle size distributions in Yinchuan, China, were measured during March and April 2014, using APS-3321 sampler. The distributions were measured under different dust conditions (background, floating dust, blowing dust, and dust storm) and statistical analyses were performed. The results showed that, under different dust conditions, the instantaneous number concentrations of dust particles differed widely. For example, during blowing sand and dust storm conditions, instantaneous dust pa...

  8. Characterization of synoptic patterns causing dust outbreaks that affect the Arabian Peninsula

    Science.gov (United States)

    Hermida, L.; Merino, A.; Sánchez, J. L.; Fernández-González, S.; García-Ortega, E.; López, L.

    2018-01-01

    Dust storms pose serious weather hazards in arid and semiarid regions of the earth. Understanding the main synoptic conditions that give rise to dust outbreaks is important for issuing forecasts and warnings to the public in cases of severe storms. The aim of the present study is to determine synoptic patterns that are associated with or even favor dust outbreaks over the Arabian Peninsula. In this respect, red-green-blue dust composite images from the Meteosat Second Generation (MSG) satellite are used to detect dust outbreaks affecting the Arabian Peninsula, with possible influences in southwestern Asia and northeastern Africa, between 2005 and 2013. The Meteosat imagery yielded a sample of 95 dust storm days. Meteorological fields from NCEP/NCAR reanalysis data of wind fields at 10 m and 250 hPa, mean sea level pressure, and geopotential heights at 850 and 500 hPa were obtained for the dust storm days. Using principal component analysis in T-mode and non-hierarchical k-means clustering, we obtained four major atmospheric circulation patterns associated with dust outbreaks during the study days. Cluster 4 had the largest number of days with dust events, which were constrained to summer, and cluster 3 had the fewest. In clusters 1, 2 and 3, the jet stream favored the entry of a low-pressure area or trough that varied in location between the three clusters. Their most northerly location was found in cluster 4, along with an extensive low-pressure area supporting strong winds over the Arabian Peninsula. The spatial distribution of aerosol optical depth for each cluster obtained was characterized using the Moderate Resolution Imaging Spectroradiometer data. Then, using METAR stations, clusters were also characterized in terms of frequency and visibility.

  9. [House dust mites at Icelandic farms].

    Science.gov (United States)

    Gudmundsson, Gunnar; Sigurdarson, Sigurdur Thór; Tómasson, Kristinn; Gíslason, Davíd; Hallas, Thorkill

    2008-11-01

    Sensitization to Dermatophagoides pteronyssinus (D. pteronyssinus) occurs in 9% of the Reykjavik population, despite the fact that no Der p 1 antigen has been found in the area. A recent study revealed that sensitized persons more often had a childhood history of work or holiday stay in rural areas than controls. As a follow up we studied the risk of exposure to mites in farmland dwellings. In a survey of work-related lung disorders among farmers in the south and west of Iceland, 80 samples of house dust, representing 42 farms, were collected from bedroom mattresses and the floors in living rooms and examined for mites. Treatment of samples was identical with the method used earlier in the Reykjavik investigation (ECRHS II). In contrast to the Reykjavik results, dust from farm dwellings showed a large diversity of mites. Seventeen taxons were found, with Acarus siro and D. pteronyssinus in 13 and 8 farms respectively, but the samples did not show signs that any of the taxons actually had lived or reproduced where they were collected. The finding of D. pteronyssinus in farmland dwellings provides a possible explanation of why some Reykjavik citizens might have developed sensitization to this mite, even though cross sensitization to other species of mites could give a false positive reaction to D. pteronyssinus in at least some of those cases. Our observations did not support the idea that the mites were living in the dwellings and an explanation for their occurrence must be sought in the outdoor environment.

  10. Variability of particle size-specific fractions of personal coal mine dust exposures.

    Science.gov (United States)

    Seixas, N S; Hewett, P; Robins, T G; Haney, R

    1995-03-01

    This study estimated the ratio of the tracheo-bronchial dust fraction to the fraction collected by a respirable dust sampler for a variety of job classifications found in conventional, continuous, and longwall coal mining sections. The ratios could then be applied in epidemiologic studies to existing respirable dust measurements to estimate thoracic mass concentrations for evaluation of the relative importance of the respirable and thoracic dust fractions to obstructive lung disease. Data collected include particle size distributions from four U.S. underground coal mines using eight-stage personal cascade impactors. A total of 180 samples were examined by mine, occupation and occupations grouped by proximity to the mine face, and by mining technology. Several fractions--that collected by the 10-mm nylon cyclone, the American Conference of Governmental Industrial Hygienists respirable and thoracic particulate mass fractions, and the estimated alveolar and tracheo-bronchial deposition fractions--were estimated. These were not significantly different when grouped by occupation, by proximity of work to the mine face, or by the type of mining technology in use. Distributions from one mine varied from the others, perhaps because it used diesel equipment in the haulage ways, which contributed to the fine aerosol fractions. Results suggest that although the tracheo-bronchial dust fraction may contribute to the development of obstructive lung disease, occupation-specific tracheo-bronchial dust fractions are not likely to produce stronger exposure-response estimates than the historically collected respirable dust concentrations.

  11. Air-conditioner filters enriching dust mites allergen.

    Science.gov (United States)

    Zhan, Xiaodong; Li, Chaopin; Xu, Haifeng; Xu, Pengfei; Zhu, Haibin; Diao, Jidong; Li, Na; Zhao, Beibei

    2015-01-01

    We detected the concentration of dust mites allergen (Der f1 & Der p1) in the air of different places before and after the starting of air-conditioners in Wuhu City, Anhui, China, and to discuss the relation between the dust mites allergen in air-conditioner filters and the asthma attack. The dust samples were collected from the air-conditioner filters in dining rooms, shopping malls, hotels and households respectively. Concentrations of dust mites major group allergen 1 (Der f 1, Der p1) were detected with enzyme linked immunosorbent assay (ELISA), and the dust mite immune activities were determined by dot-ELISA. The concentration of Der f1 in dining rooms, shopping malls, hotels and households was 1.52 μg/g, 1.24 μg/g, 1.31 μg/g and 1.46 μg/g respectively, and the concentration of Der p1 in above-mentioned places was 1.23 μg/g, 1.12 μg/g, 1.16 μg/g and 1.18 μg/g respectively. The concentration of Der f1 & Der p1 in air was higher after the air-conditioners starting one hours later, and the difference was significant (Pair-conditioner filters can enrich dust mites major group allergen, and the allergens can induce asthma. The air-conditioner filters shall be cleaned or replaced regularly to prevent or reduce accumulation of the dust mites and its allergens.

  12. Seasonal and occupational trends of five organophosphate pesticides in house dust.

    Science.gov (United States)

    Smith, Marissa N; Workman, Tomomi; McDonald, Katie M; Vredevoogd, Melinda A; Vigoren, Eric M; Griffith, William C; Thompson, Beti; Coronado, Gloria D; Barr, Dana; Faustman, Elaine M

    2017-07-01

    Since 1998, the University of Washington's Center for Child Environmental Health Risks Research has followed a community-based participatory research strategy in the Lower Yakima Valley of Washington State to assess pesticide exposure among families of Hispanic farmworkers. As a part of this longitudinal study, house dust samples were collected from both farmworker and non-farmworker households, across three agricultural seasons (thinning, harvest and non-spray). The household dust samples were analyzed for five organophosphate pesticides: azinphos-methyl, phosmet, malathion, diazinon, and chlorpyrifos. Organophosphate pesticide levels in house dust were generally reflective of annual use rates and varied by occupational status and agricultural season. Overall, organophosphate pesticide concentrations were higher in the thinning and harvest seasons than in the non-spray season. Azinphos-methyl was found in the highest concentrations across all seasons and occupations. Farmworker house dust had between 5- and 9-fold higher concentrations of azinphos-methyl than non-farmworker house dust. Phosmet was found in 5-7-fold higher concentrations in farmworker house dust relative to non-farmworker house dust. Malathion and chlorpyriphos concentrations in farmworker house dust ranged between 1.8- and 9.8-fold higher than non-farmworker house dust. Diazinon showed a defined seasonal pattern that peaked in the harvest season and did not significantly differ between farmworker and non-farmworker house dust. The observed occupational differences in four out of five of the pesticide residues measured provides evidence supporting an occupational take home pathway, in which workers may bring pesticides home on their skin or clothing. Further, these results demonstrate the ability of dust samples to inform the episodic nature of organophosphate pesticide exposures and the need to collect multiple samples for complete characterization of exposure potential.

  13. Directional Unfolded Source Term (DUST) for Compton Cameras.

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, Dean J.; Mitchell, Dean J.; Horne, Steven M.; O' Brien, Sean; Thoreson, Gregory G

    2018-03-01

    A Directional Unfolded Source Term (DUST) algorithm was developed to enable improved spectral analysis capabilities using data collected by Compton cameras. Achieving this objective required modification of the detector response function in the Gamma Detector Response and Analysis Software (GADRAS). Experimental data that were collected in support of this work include measurements of calibration sources at a range of separation distances and cylindrical depleted uranium castings.

  14. Saharan dust from a marine perspective: sediment-trap time series off Mauritania

    Science.gov (United States)

    Friese, Carmen; Stuut, Jan-Berend; van der Does, Michelle; Fischer, Gerhard

    2014-05-01

    The particle size of mineral dust is often used as a tool to reconstruct paleoenvironmental conditions in the source of the dust. Both in on-land (loess), lacustrine, and in marine archives, the size of dust deposits is considered a proxy for paleo-wind intensity. However, next to wind strength, the particle size of aeolian deposits is also influenced by various other parameters such as source-to-sink distance, altitude at which the particles have been transported, and various other environmental conditions in the sources of the dust. To verify if we can quantify a relationship between the size of mineral dust particles and prevailing environmental conditions, we study "modern" dust. Here we present grain-size distributions of Saharan dust that was collected in a marine sediment trap, which is situated off Cape Blanc, ~400 km offshore the Mauritanian coast. In this trap, dust is collected that is sinking through the water column to the ocean floor. The temporal resolution of the trap is 1-2 weeks. The time series was started in the late 1980's and is still being continued.

  15. Studies on airborne dust particles by neutron activation analysis

    International Nuclear Information System (INIS)

    Aoki, Atsushi; Ishii, Taka; Tomiyama, Tsuyoshi; Yamamoto, Isao.

    1974-01-01

    Neutron activation analysis was performed on the airborne dust particles collected at six places with different contaminating circumstances in Kyoto city and the suburbs of Okayama city, using an open type low volume air sampler with a membrance filter attached. Radioactivation by neutrons was performed with the reactor in the Research Reactor Institute of Kyoto University. Short half-life nuclides activated by thermal neutrons were measured. The concentration of airborne dust was usually high in November and December, while Na, Mn, K, etc. probably owing to soil origin showed similar seasonal change to the dust particles, as expected. The concentrations Cl and Br were in proportion to traffic volume, and it was considered to be caused by the exhaust gas from cars. Zn, V. et. were thick in factory areas, which seemed to show the relationship with oil fuel consumption. (Kobatake, H.)

  16. Atmospheric processing of iron carried by mineral dust

    Directory of Open Access Journals (Sweden)

    S. Nickovic

    2013-09-01

    Full Text Available Nutrification of the open ocean originates mainly from deposited aerosol in which the bio-avaliable iron is likely to be an important factor. The relatively insoluble iron in dust from arid soils becomes more soluble after atmospheric processing and, through its deposition in the ocean, could contribute to marine primary production. To numerically simulate the atmospheric route of iron from desert sources to sinks in the ocean, we developed a regional atmospheric dust-iron model that included parameterization of the transformation of iron to a soluble form caused by dust mineralogy, cloud processes and solar radiation. When compared with field data on the aerosol iron, which were collected during several Atlantic cruises, the results from the higher-resolution simulation experiments showed that the model was capable of reproducing the major observed patterns.

  17. Identifying Biases in Dust Source Functions

    Science.gov (United States)

    Evan, A. T.; Wang, W.; Zhao, C.

    2017-12-01

    The Sahara is the largest desert in the world and accounts for more than 50% of global dust emission. However, it is difficult to identify dust source regions as the Sahara is vastly uninhabited. In order to model North African dust, previous works have used satellite data to construct so-called dust source functions. Here we examine such dust source function using output from multi-year runs with the Weather Research and Forecasting with Chemistry (WRF-Chem) model. We find that dust source functions based on satellite data overestimate DOD in the Sahel and the western Sahara region. To eliminate the biases of the dust source function due to advection, we develop a new source function using DOD in the lowest 1 km from the model. This work suggests that dust source functions constructed with satellite retrievlas of optical depth may overestimate dust emission in the downwind regions and DOD may not be a good proxy for the source function.

  18. A Comparison of Single and Multi-Stream Recycling Systems in Ontario, Canada

    Directory of Open Access Journals (Sweden)

    Calvin Lakhan

    2015-06-01

    Full Text Available This study examines differences in cost and recycling performance between single and multi-stream recycling systems in Ontario, Canada. Using panel data from 223 provincial municipalities spanning a ten year period, focus is placed on analyzing: (a Are material management costs for municipalities who implement single stream collection less than those that implement multi stream collection? (b Are recycling rates for single stream municipalities higher than municipalities with multi stream collection? (c Do municipalities with multi stream collection realize higher revenues from the sale of recyclable material? The results of the analysis show that while single stream recycling programs recycle more than multi stream programs, they face significantly higher material management costs. This was contrary to the prevailing opinion that single stream recycling is a cheaper alternative to multi-stream recycling. As far as can be ascertained, this is one of the few studies of its kind to examine the differences in material management costs and recycling performance between single and multi-stream recycling systems. This topic is of increasing importance, as single stream recycling is being touted as preferred waste management option in both Ontario and abroad.

  19. Towards a multimetric index for the assessment of Dutch streams using benthic macroinvertebrates

    NARCIS (Netherlands)

    Vlek, H.E.; Verdonschot, P.F.M.; Nijboer, R.C.

    2004-01-01

    This study describes the development of a macroinvertebrate based multimetric index for two stream types, fast and slow running streams, in the Netherlands within the AQEM project. Existing macroinvertebrate data (949 samples) were collected from these stream types from all over the Netherlands. All

  20. A Four-Level Hierarchy for Organizing Wildland Stream Resource Information

    Science.gov (United States)

    Harry Parrott; Daniel A. Marion; R. Douglas Perkinson

    1989-01-01

    An analysis of current USDA Forest Service methods of collecting and using wildland stream resource data indicates that required information can be organized into a four-level hierarchy. Information at each level is tiered with information at the preceding level. Level 1 is the ASSOCIATION, which is differentiated by stream size and flow regime. Level 2, STREAM TYPE,...

  1. Fugitive dust control experiments using directed airflow in dumping operations

    International Nuclear Information System (INIS)

    Winberg, M.R.; Menkhaus, D.E.; Thompson, D.N.; Wixom, V.E.

    1992-07-01

    Experiments were conducted to evaluate the degree of dust control for using directed airflow in a funnel during dumping operations. Retrieved buried transuranic waste or overburden soils are expected to require focusing the retrieved material into a transporter box with a funnel and control of transuranic-contaminated dust at the funnel is mandatory. In these experiments, the Idaho National Engineering Laboratory soil was dumped into a full-scale funnel (capable of focusing waste into a 4 x 4 x 8 ft box) that was specially equipped with a directed airflow into the funnel. The degree of dust control was determined by comparing collected dust on filters in high volume samplers (strategically located) for a baseline case with no airflow to cases with airflow. Tests involving airflow into the funnel spanned a range of airflows at the opening between 15--100 linear feet per minute. The basic result is that the directed airflow concept is adequate to control dust spread during dumping

  2. Respirable dust and respirable silica exposure in Ontario gold mines.

    Science.gov (United States)

    Verma, Dave K; Rajhans, Gyan S; Malik, Om P; des Tombe, Karen

    2014-01-01

    A comprehensive survey of respirable dust and respirable silica in Ontario gold mines was conducted by the Ontario Ministry of Labor during 1978-1979. The aim was to assess the feasibility of introducing gravimetric sampling to replace the assessment method which used konimeters, a device which gave results in terms of number of particles per cubic centimeter (ppcc) of air. The study involved both laboratory and field assessments. The field assessment involved measurement of airborne respirable dust and respirable silica at all eight operating gold mines of the time. This article describes the details of the field assessment. A total of 288 long-term (7-8 hr) personal respirable dust air samples were collected from seven occupational categories in eight gold mines. The respirable silica (α-quartz) was determined by x-ray diffraction method. The results show that during 1978-1979, the industry wide mean respirable dust was about 1 mg/m(3), and the mean respirable silica was 0.08 mg/m(3.)The mean% silica in respirable dust was 7.5%. The data set would be useful in future epidemiological and health studies, as well as in assessment of workers' compensation claims for occupational diseases such as silicosis, chronic obstructive pulmonary disease (COPD), and autoimmune diseases such as renal disease and rheumatoid arthritis.

  3. House dust mites in the city of Lima, Peru.

    Science.gov (United States)

    Croce, M; Costa-Manso, E; Baggio, D; Croce, J

    2000-01-01

    Since mites are the most common house dust allergens, knowledge about the species most prevalent in a region is important for diagnostic and specific immunotherapy purposes. In order to establish the prevalence of house dust mites in different city districts, 100 house dust samples were collected from different parts of Lima. Lima is a city of tropical climate located along the coast of the Pacific Ocean. The relative air humidity is 80-90% and the various districts studied are located at altitudes ranging from 37-355 meters. The mite Blomia tropicalis was the organism most frequently detected, being present in 59% of the house dust samples. Dermatophagoides pteronyssinus occupied second place (15.9%), followed by Chortoglyphus arcuatus and Tyrophagus putrescentiae. These four mites, taken together, represented more than 90% of the mites detected. No specimen of the species Dermatophagoides farinae was detected. We conclude that B. tropicalis and D. pteronyssinus are the most common house dust mites in Lima. Considering the high prevalence of B. tropicalis in Lima and the fact that its cross-reactivity with antigens of the mites of the family Pyroglyphidae is minimal, we conclude that sensitization to this mite should be investigated separately in allergic patients living in Lima.

  4. [Wood dust exposure in handicraft companies in Lazio: preliminary findings].

    Science.gov (United States)

    Campopiano, A; Basili, F; Boccanera, S; Cannizzaro, A; Olori, A; Ramires, D; Amici, S; Sbardella, L; Amaro, P

    2007-01-01

    The aim of this study is to evaluate the wood dust exposures characterizing the working more to risk. Two selectors for inhalable fraction were been used: IOM sampler (Institute Occupational Medicine) and conical sampler. The sampling time is choosen by environmental airborne dust and it has varied around three and four hours. The surveys involved some companies of the Lazio that carried out the second working of wood that predict the transformation in ultimate products. The woodworking processes investigated have been grouped in three different classes: wood dissection; planning and moulding; sanding. The results have shown that the medium concentration of wood dusts, obtained in three processes investigated ranges from 2 mg/m3 to 4 mg/m3. The higher amounts is of 16 mg/m3 and it have been obtained during the sanding. Moreover the dust collected by IOM sampler was always higher than by conical sampler probably it is due to large particulates that were projected into IOM causing an overestimate of the amount of wood dust particulate that was inhalable. This study need to of more personal sampling for being able to carry out an exhaustive statistical analysis.

  5. Microbial biodiversity in glacier-fed streams.

    Science.gov (United States)

    Wilhelm, Linda; Singer, Gabriel A; Fasching, Christina; Battin, Tom J; Besemer, Katharina

    2013-08-01

    While glaciers become increasingly recognised as a habitat for diverse and active microbial communities, effects of their climate change-induced retreat on the microbial ecology of glacier-fed streams remain elusive. Understanding the effect of climate change on microorganisms in these ecosystems is crucial given that microbial biofilms control numerous stream ecosystem processes with potential implications for downstream biodiversity and biogeochemistry. Here, using a space-for-time substitution approach across 26 Alpine glaciers, we show how microbial community composition and diversity, based on 454-pyrosequencing of the 16S rRNA gene, in biofilms of glacier-fed streams may change as glaciers recede. Variations in streamwater geochemistry correlated with biofilm community composition, even at the phylum level. The most dominant phyla detected in glacial habitats were Proteobacteria, Bacteroidetes, Actinobacteria and Cyanobacteria/chloroplasts. Microorganisms from ice had the lowest α diversity and contributed marginally to biofilm and streamwater community composition. Rather, streamwater apparently collected microorganisms from various glacial and non-glacial sources forming the upstream metacommunity, thereby achieving the highest α diversity. Biofilms in the glacier-fed streams had intermediate α diversity and species sorting by local environmental conditions likely shaped their community composition. α diversity of streamwater and biofilm communities decreased with elevation, possibly reflecting less diverse sources of microorganisms upstream in the catchment. In contrast, β diversity of biofilms decreased with increasing streamwater temperature, suggesting that glacier retreat may contribute to the homogenisation of microbial communities among glacier-fed streams.

  6. Charged dust in saturn's magnetosphere

    International Nuclear Information System (INIS)

    Mendis, D.A.; Hill, J.R.; Houpis, H.L.F.

    1983-01-01

    Gravito-electrodynamic theory of charged dust grains is used to explain a variety of phenomena in those portions of the Saturnian ring system that are known to be dominated by fine (micron- and submicron-sized) dust, and in which collisional forces and Coulomb drag can be neglected. Among the phenomena discussed are the formation and evolution of the rotating near-radial spokes in the B-ring, the formation of waves in the F-ring, the cause of eccentricities of certain isolated ringlets, and the origin and morphology of the broad diffuse E-ring. Several novel processes predicted by the gravitoelectrodynamic theory, including 'magneto-gravitational capture' of exogenic dust by the magnetosphere, '1:1 magneto-gravitational orbital resonances' of charged dust with nearby satellites, and 'gyro-orbital resonances,' are used to explain individual observations. The effect of a ring current associated with this charged dust is also evaluated. Finally, the cosmogonic implications of the magneto-gravitational theory are briefly discussed. While several (although not all) of these processes have been discussed by one or more of the present authors elsewhere, the purpose of this paper is to synthesize all these processes within the framework of gravito-electrodynamics, and also to show its range of applicability within Saturn's ring system

  7. Constraints on astronomical silicate dust

    International Nuclear Information System (INIS)

    Sorrell, W.H.

    1990-01-01

    Numerical radiative-transfer models are used to discuss the properties of circumstellar dust grains around the premain-sequence star AB Aur (HD 31293). It is assumed that the dust consists of a silicate-graphite mixture with Draine and Lee (1984) optical properties. The modeling technique is to match the observed FUV through FIR energy distribution with the spectral energy distribution predicted for a spherical dust shell around a luminous hot star. Special attention is given to matching the observed 10-micron silicate emission feature and the observed circumstellar absorption curve at UV wavelengths, making it possible to strengthen constraints on dust-grain opacity and chemical composition. It is concluded that, although silicate grains can explain the observed 10-micron emission feature, the Draine and Lee silicate-graphite mixture cannot explain the observed FUV circumstellar absorption at the same time. The dust shell around AB Aur contains an additional population of small particles, the most likely candidate being amorphous carbon grains in a nonhydrogenated form. 18 refs

  8. Constraints on astronomical silicate dust

    Science.gov (United States)

    Sorrell, Wilfred H.

    1990-01-01

    Numerical radiative-transfer models are used to discuss the properties of circumstellar dust grains around the premain-sequence star AB Aur (HD 31293). It is assumed that the dust consists of a silicate-graphite mixture with Draine and Lee (1984) optical properties. The modeling technique is to match the observed FUV through FIR energy distribution with the spectral energy distribution predicted for a spherical dust shell around a luminous hot star. Special attention is given to matching the observed 10-micron silicate emission feature and the observed circumstellar absorption curve at UV wavelengths, making it possible to strengthen constraints on dust-grain opacity and chemical composition. It is concluded that, although silicate grains can explain the observed 10-micron emission feature, the Draine and Lee silicate-graphite mixture cannot explain the observed FUV circumstellar absorption at the same time. The dust shell around AB Aur contains an additional population of small particles, the most likely candidate being amorphous carbon grains in a nonhydrogenated form.

  9. Aeolian dust emissions in Southern Africa: field measurements of dynamics and drivers

    Science.gov (United States)

    Wiggs, Giles; Thomas, David; Washington, Richard; King, James; Eckardt, Frank; Bryant, Robert; Nield, Joanna; Dansie, Andrew; Baddock, Matthew; Haustein, Karsten; Engelstaedter, Sebastian; von Holdt, Johannah; Hipondoka, Martin; Seely, Mary

    2016-04-01

    Airborne dust derived from the world's deserts is a critical component of Earth System behaviour, affecting atmospheric, oceanic, biological, and terrestrial processes as well as human health and activities. However, very few data have been collected on the factors that control dust emission from major source areas, or on the characteristics of the dust that is emitted. Such a paucity of data limits the ability of climate models to properly account for the radiative and dynamical impacts triggered by atmospheric dust. This paper presents field data from the DO4 Models (Dust Observations for Models) project that aims to understand the drivers of variability in dust emission processes from major source areas in southern Africa. Data are presented from three field campaigns undertaken between 2011 and 2015. We analysed remote sensing data to identify the key geomorphological units in southern Africa which are responsible for emission of atmospheric dust. These are the Makgadikgadi pans complex in northern Botswana, the ephemeral river valleys of western Namibia, and Etosha Pan in northern Namibia. Etosha Pan is widely recognised as perhaps the most significant source of atmospheric dust in the southern hemisphere. We deployed an array of field equipment within each source region to measure the variability in and dynamics of aeolian erosivity, as well as dust concentration and flux characteristics. This equipment included up to 11 meteorological stations measuring wind shear stress and other standard climatic parameters, Cimel sun photometers, a LiDAR, sediment transport detectors, high-frequency dust concentration monitors, and dust flux samplers. Further data were gathered at each site on the dynamics of surface characteristics and erodibility parameters that impact upon erosion thresholds. These data were augmented by use of a Pi-Swerl portable wind tunnel. Our data represent the first collected at source for these key dust emission areas and highlight the

  10. Dust-on-snow and the Timing of Peak Streamflow in the Upper Rio Grande

    Science.gov (United States)

    Steele, C. M.; Elias, E.; Moffitt, A.; Beltran, I.; Rango, A.

    2015-12-01

    Dust radiative forcing on high elevation snowpack is well-documented in the southern Rockies. Various field studies show that dust deposits decrease snow albedo and increase absorption of solar radiation, leading to earlier snowmelt and peak stream flows. These findings have implications for the use of temperature-index snow runoff models (such as the Snowmelt Runoff Model [SRM]) for predicting streamflow. In previous work, we have used SRM to simulate historical streamflow from 26 Upper Rio Grande sub-basins. Because dust radiative forcing can alter the relation between temperature and snowmelt, we wanted to find out if there is evidence of dust radiative forcing and earlier snowmelt in our study basins, particularly for those years where SRM was less successful in simulating streamflow. To accomplish this we have used openly-available data such as EPA air quality station measurements of particulate matter up to 10 micrometers (PM10); streamflow data from the USGS National Water Information System and Colorado Division of Water Resources; temperature, precipitation and snow water equivalent (SWE) from NRCS SNOTEL stations and remotely sensed data products from the MODIS sensor. Initial analyses indicate that a connection between seasonal dust concentration and streamflow timing (date of onset of warm-season snowmelt, date of streamflow center-of-volume) can be detected. This is further supported by time series analysis of MODIS-derived estimates of snow albedo and dust radiative-forcing in alpine and open subalpine snow fields.

  11. Music Streaming in Denmark

    DEFF Research Database (Denmark)

    Pedersen, Rasmus Rex

    This report analyses how a ’per user’ settlement model differs from the ‘pro rata’ model currently used. The analysis is based on data for all streams by WiMP users in Denmark during August 2013. The analysis has been conducted in collaboration with Christian Schlelein from Koda on the basis...

  12. River and Stream Pollution

    Science.gov (United States)

    ... plants to grow. The two most common nutrients found in water are nitrogen and phosphorus. They cause algae to ... streams and rivers clean helps keep all the water downstream clean, too. Other stuff you might ... What's That Word Scientific Dictionary Not sure of what a word ...

  13. The Rabbit Stream Cipher

    DEFF Research Database (Denmark)

    Boesgaard, Martin; Vesterager, Mette; Zenner, Erik

    2008-01-01

    The stream cipher Rabbit was first presented at FSE 2003, and no attacks against it have been published until now. With a measured encryption/decryption speed of 3.7 clock cycles per byte on a Pentium III processor, Rabbit does also provide very high performance. This paper gives a concise...

  14. Stream Management: A Rebirth

    Science.gov (United States)

    Coler, Robert A.; Zatryka, Simon A.

    1974-01-01

    This article describes a stream management course designed to give non-science majors an in-depth study of water quality. The course includes work in determining and measuring water quality parameters and the discussion of management techniques. Construction of a Hewitt Ramp and wing deflectors are illustrated in the article. (MA)

  15. Streaming-video produktion

    DEFF Research Database (Denmark)

    Grønkjær, Poul

    2004-01-01

     E-learning Lab på Aalborg Universitet har i forbindelse med forskningsprojektet Virtuelle Læringsformer og Læringsmiljøer foretaget en række praktiske eksperimenter med streaming-video produktioner. Hensigten med denne artikel er at formidle disse erfaringer. Artiklen beskriver hele produktionsf...... E-learning Lab på Aalborg Universitet har i forbindelse med forskningsprojektet Virtuelle Læringsformer og Læringsmiljøer foretaget en række praktiske eksperimenter med streaming-video produktioner. Hensigten med denne artikel er at formidle disse erfaringer. Artiklen beskriver hele...... produktionsforløbet: fra ide til færdigt produkt, forskellige typer af præsentationer, dramaturgiske overvejelser samt en konceptskitse. Streaming-video teknologien er nu så udviklet med et så tilfredsstillende audiovisuelt udtryk at vi kan begynde at fokusere på, hvilket indhold der er velegnet til at blive gjort...... tilgængeligt uafhængigt af tid og sted. Afslutningsvis er der en række kildehenvisninger, blandt andet en oversigt over de streaming-video produktioner, som denne artikel bygger på....

  16. Numerical Modelling of Streams

    DEFF Research Database (Denmark)

    Vestergaard, Kristian

    In recent years there has been a sharp increase in the use of numerical water quality models. Numeric water quality modeling can be divided into three steps: Hydrodynamic modeling for the determination of stream flow and water levels. Modelling of transport and dispersion of a conservative...

  17. The Rabbit Stream Cipher

    DEFF Research Database (Denmark)

    Boesgaard, Martin; Vesterager, Mette; Zenner, Erik

    2008-01-01

    The stream cipher Rabbit was first presented at FSE 2003, and no attacks against it have been published until now. With a measured encryption/decryption speed of 3.7 clock cycles per byte on a Pentium III processor, Rabbit does also provide very high performance. This paper gives a concise...... description of the Rabbit design and some of the cryptanalytic results available....

  18. Determinants of manganese levels in house dust samples from the CHAMACOS cohort

    International Nuclear Information System (INIS)

    Gunier, R.B.; Jerrett, M.; Smith, D.R.; Jursa, T.; Yousefi, P.; Camacho, J.; Hubbard, A.; Eskenazi, B.; Bradman, A.

    2014-01-01

    Introduction: Manganese (Mn) is an essential nutrient, but at high exposure levels Mn is a neurotoxicant. The fungicides maneb and mancozeb are approximately 21% Mn by weight and more than 150,000 kg are applied each year to crops in the Salinas Valley, California. It is not clear, however, whether agricultural use of these fungicides increases Mn levels in homes. Materials and methods: We collected house dust samples from 378 residences enrolled in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) study with a second sample collected approximately nine months later from 90 of the residences. House dust samples were analyzed for Mn using inductively coupled plasma optical emission spectroscopy. Information from interviews, home inspections, and pesticide use reports was used to identify potential predictors of Mn dust concentrations and loadings. Results: Mn was detectable in all dust samples. The median Mn concentration was 171 μg/g and median Mn loading was 1,910 μg/m 2 at first visit. In multivariable models, Mn dust concentrations and loadings increased with the number of farmworkers in the home and the amount of agricultural Mn fungicides applied within three kilometers of the residence during the month prior to dust sample collection. Dust concentrations of Mn and other metals (lead, cadmium and chromium) were higher in residences located in the southern Salinas Valley compared those located in other areas of the Salinas Valley. Dust loadings of Mn and other metals were also higher in residences located on Antioch Loam soil than other soil types, and in homes with poor or average housekeeping practices. Conclusions: Agricultural use of Mn containing fungicides was associated with Mn dust concentrations and loadings in nearby residences and farmworker homes. Housekeeping practices and soil type at residence were also important factors related to dust metal concentrations and loadings. - Highlights: • Manganese dust

  19. Determinants of manganese levels in house dust samples from the CHAMACOS cohort

    Energy Technology Data Exchange (ETDEWEB)

    Gunier, R.B., E-mail: gunier@berkeley.edu [Center for Environmental Research and Children’s Health (CERCH), School of Public Health, University of California, Berkeley, CA (United States); Jerrett, M. [Center for Environmental Research and Children’s Health (CERCH), School of Public Health, University of California, Berkeley, CA (United States); Smith, D.R.; Jursa, T. [Microbiology and Environmental Toxicology, University of California, Santa Cruz, CA (United States); Yousefi, P.; Camacho, J.; Hubbard, A.; Eskenazi, B.; Bradman, A. [Center for Environmental Research and Children’s Health (CERCH), School of Public Health, University of California, Berkeley, CA (United States)

    2014-11-01

    Introduction: Manganese (Mn) is an essential nutrient, but at high exposure levels Mn is a neurotoxicant. The fungicides maneb and mancozeb are approximately 21% Mn by weight and more than 150,000 kg are applied each year to crops in the Salinas Valley, California. It is not clear, however, whether agricultural use of these fungicides increases Mn levels in homes. Materials and methods: We collected house dust samples from 378 residences enrolled in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) study with a second sample collected approximately nine months later from 90 of the residences. House dust samples were analyzed for Mn using inductively coupled plasma optical emission spectroscopy. Information from interviews, home inspections, and pesticide use reports was used to identify potential predictors of Mn dust concentrations and loadings. Results: Mn was detectable in all dust samples. The median Mn concentration was 171 μg/g and median Mn loading was 1,910 μg/m{sup 2} at first visit. In multivariable models, Mn dust concentrations and loadings increased with the number of farmworkers in the home and the amount of agricultural Mn fungicides applied within three kilometers of the residence during the month prior to dust sample collection. Dust concentrations of Mn and other metals (lead, cadmium and chromium) were higher in residences located in the southern Salinas Valley compared those located in other areas of the Salinas Valley. Dust loadings of Mn and other metals were also higher in residences located on Antioch Loam soil than other soil types, and in homes with poor or average housekeeping practices. Conclusions: Agricultural use of Mn containing fungicides was associated with Mn dust concentrations and loadings in nearby residences and farmworker homes. Housekeeping practices and soil type at residence were also important factors related to dust metal concentrations and loadings. - Highlights: • Manganese dust

  20. Lidar ratio derived for pure dust aerosols: multi-year micro pulse lidar observations in a Saharan dust-influenced region

    OpenAIRE

    Córdoba-Jabonero, Carmen; Adame, José Antonio; Campbell, James R.; Cuevas Agulló, Emilio; Díaz González, Juan Pedro; Expósito, Francisco J.; Gil-Ojeda, Manuel

    2016-01-01

    El volumen 119 de 2016 de la revista EPJ Web of Conferences recoge las ponencias del 27th International Laser Radar Conference (ILRC 27) A seasonal distribution of the Lidar Ratio (LR, extinction-to-backscattering coefficient ratio) for pure Saharan dust particles has been achieved. Simultaneous MPLNET/Micro Pulse lidar measurements in synergy with AERONET sun-photometer data were collected in the Tenerife area, a Saharan dust-influenced region, from June 2007 to November 2009. Dusty ...

  1. Microbiological characterization of stable resuspended dust

    Directory of Open Access Journals (Sweden)

    Nora Kováts

    2016-06-01

    Full Text Available Objectives: Air quality in the stables is characterized by elevated level of dust and aeroallergens which are supposed to directly cause or exacerbate several respiratory disorders. The most often recognized problem is recurrent airway obstruction (RAO, previously known as chronic obstructive pulmonary disease (COPD. There is some indication that aeroallergens (among them endotoxins may also cause inflammation in human airways and may exceed safe levels in stables. Monitoring studies have covered mainly the determination of the concentration of respirable particles and of culturable fungi and their toxins. However, these particles do not only directly affect the respiratory system, but might act as a carrier conveying toxic contaminants and biological agents such as bacteria. In a typical, 20-horse Hungarian stable, microbial community of respirable fraction of resuspended dust has been characterized to reveal if these particles convey hazardous pathogenic bacteria, posing risk to either horses or staff. Material and Methods: Resuspended dust was sampled using a mobile instrument. The instrument contains a PARTISOL-FRM model 2000 sampler that was operated at a flow rate of 16.7 l/min and a cyclone separator which collected the particulate matter with an aerodynamic size between 1 μm and 10 μm (PM1–10 fraction. Microbial taxa were identified by culture-independent next generation sequencing (NGS of variable 16S ribosomal ribonucleic acid (rRNA gene regions. Results: In total, 1491 different taxa were identified, of them 384 were identified to species level, 961 to genus level. The sample was dominated by common ubiquitous soil and organic material-dwelling taxa. Conclusions: Pathogens occurred at low abundance, and were represented by mostly facultative human pathogens, with the prevalence of Staphylococcus species.

  2. Metal content in street dust as a reflection of atmospheric dust emissions from coal power plants, metal smelters, and traffic.

    Science.gov (United States)

    Žibret, Gorazd; Van Tonder, Danel; Žibret, Lea

    2013-07-01

    Resuspended street dust is a source of inhalable particles in urban environments. Despite contaminated street dust being a possible health risk factor for local population, little is known about the contribution of atmospheric dust emissions and other factors to the content of toxic metals in street dust. The impact of smelting, traffic, and power plants on metal contaminates in street dust is the focus of street dust sampling at 46 locations in the Witbank area (Republic of South Africa). This area is characterized by numerous open-pit coal mines in the Karoo coal basin, which provides a cheap source of energy to numerous metallurgical smelters and ironworks and supplies coal to the coal-fired power plants located nearby. Street dust was collected on asphalt or concrete surfaces with hard plastic brushes, avoiding collecting of possible sand, soil, or plant particles. Chemical analysis was done on the <0.125 mm fraction using inductively coupled plasma mass spectrometry subsequent to total digestion. Exceptionally high concentrations of metals were detected with concentrations of Fe reaching 17.7%, Cr 4.3%, Mn 2%, Ni 366 mg/kg, and V 4,410 mg/kg. Factor analysis indicates three sources for the pollution. Road traffic which contributes to the high concentrations of Cu, Pb, Sb, and Sn, with the highest impacts detected in the town of Witbank. The second source is associated with the metal smelting industry, contributing to Fe, Co, Mn, and V emissions. The highest factor scores were observed around four metallurgical smelter operations, located in the Ferrobank, Highveld, and Clewer industrial areas. Impact of vanadium smelter to street dust composition could still be detected some 20 km away from the sources. Exceptionally high concentrations of Cr were observed in four samples collected next to the Ferrobank industrial area, despite Cr not being loaded in factor 2. The last source of the pollution is most probably fly ash associated with the coal-fired power plants

  3. Macroinvertebrate diversity loss in urban streams from tropical forests.

    Science.gov (United States)

    Docile, Tatiana N; Figueiró, Ronaldo; Portela, Clayton; Nessimian, Jorge L

    2016-04-01

    The increase of human activities in recent years has significantly interfered and affected aquatic ecosystems. In this present study, we investigate the effects of urbanization in the community structure of aquatic macroinvertebrates from Atlantic Forest streams. The sampling was conducted in the mountainous region of the State of Rio de Janeiro, Brazil in 10 urban and 10 preserved streams during the dry season (August-September) of 2012. The streams were characterized for its environmental integrity conditions and physico-chemical properties of water. The macroinvertebrates were sampled on rocky substrates with a kicknet. A total of 5370 individuals were collected from all streams and were distributed among Ephemeroptera, Odonata, Plecoptera, Hemiptera, Megaloptera, Coleoptera, Trichoptera, Lepidoptera, and Diptera. In urban sites, all those orders were found, except Megaloptera, while only Mollusca was not found in preserved streams. We performed a non-metric multidimensional scaling (NMDS) analysis that separated two groups distributed among sites in urban communities and another group outside this area. The dominance was significantly higher at urban sites, while the α diversity and equitability were greater in preserved sites. A canonical correspondence analysis (CCA) was also performed, indicating that most taxa associated with high values of the Habitat Integrity Index (HII) and a few genus of the order Diptera with the high values of ammonia, total nitrogen, associated to streams in urban sites. Urban and preserved streams differ by physical-chemical variables and aquatic macroinvertebrates. In urban streams, there is most dominance, while α diversity and equitability are higher in preserved streams.

  4. Mineral phases and metals in baghouse dust from secondary aluminum production.

    Science.gov (United States)

    Huang, Xiao-Lan; El Badawy, Amro M; Arambewela, Mahendranath; Adkins, Renata; Tolaymat, Thabet

    2015-09-01

    Baghouse dust (BHD) is a solid waste generated by air pollution control systems during secondary aluminum processing (SAP). Management and disposal of BHD can be challenging in the U.S. and elsewhere. In this study, the mineral phases, metal content and metal leachability of 78 BHD samples collected from 13 different SAP facilities across the U.S. were investigated. The XRD semi-quantitative analysis of BHD samples suggests the presence of metallic aluminum, aluminum oxide, aluminum nitride and its oxides, spinel, elpasolite as well as diaspora. BHD also contains halite, sylvite and fluorite, which are used as fluxes in SAP activities. Total aluminum (Al) in the BHD samples averaged 18% by weight. Elevated concentrations of trace metals (>100 μg L(-1) As; >1000 μg L(-1) Cu, Mn, Se, Pb, Mn and Zn) were also detected in the leachate. The U.S. toxicity characteristic leaching procedure (TCLP) results showed that some samples leached above the toxicity limit for Cd, Pb and Se. Exceeding the TCLP limits in all sample is independent of facilities generating the BHD. From the metal content perspective only, it appears that BHD has a higher potential to exhibit toxicity characteristics than salt cake (the largest waste stream generated by SAP facilities). Published by Elsevier Ltd.

  5. Electrostatic Dust Cloth: A Passive Screening Method to Assess Occupational Exposure to Organic Dust in Bakeries

    Directory of Open Access Journals (Sweden)

    Carla Viegas

    2018-02-01

    Full Text Available Organic dust is widespread in the environment including occupational settings, such as bakeries. Recently, a new collection device—the electrostatic dust cloth (EDC—has been described for the assessment of occupational exposures. The aim of this study was to investigate the suitability of EDC for identifying the distribution patterns and exposure concentrations of particulate matter and microbial contaminants such as fungi and bacteria in bakeries. Twelve bakeries were selected, and dust was allowed to settle for 13 to 16 days on EDCs (a total of 33 samples. Particle counts and size distribution (0.3 µm, 0.5 µm, 1 µm, 2.5 µm, 5 µm and 10 µm were measured with direct-reading equipment. Higher EDC mass was significantly correlated (p values < 0.05 with higher fungal load on dichloran glycerol (DG18 and with particle size distribution in the 0.3 µm, 0.5 µm, 1.0 µm and 10.0 µm range. Fungal levels on malt extract agar (MEA ranged from 0 to 2886 CFU/m2 EDC in the warehouse setting, 0 to 500 CFU/m2 EDC in the production setting, and 0 to 3135 CFU/m2 EDC in the store. Penicillium sp. (42.56% was the most frequent fungi. Total bacterial load ranged from 0 to 18,859 CFU/m2 EDC in the warehouse, 0 to 71,656 CFU/m2 EDC in production, and 0 to 21,746 CFU/m2 EDC in the store. EDC assessment provided a longer-term integrated sample of organic dust, useful for identifying critical worksites in which particulate matter and bio-burden exposures are elevated. These findings suggest that EDC can be applied as a screening method for particulate matter-exposure assessment and as a complementary method to quantify exposures in occupational environments.

  6. Dust-mites: effect on lipid peroxidation.

    Science.gov (United States)

    Atambay, Metin; Karabulut, Aysun Bay; Aycan, Ozlem Makbule; Kilic, Eser; Yazar, Suleyman; Saraymen, Recep; Karaman, Ulku; Daldal, Nilgun

    2006-01-01

    Dust-mites are present in our homes, feed on dead exfoliated skin and other organic material. It is also known that oxidative stress may lead to cellular damage that can be confirmed by markers of cellular disruption. Oxidative stress in various infective processes has been documented. We investigated whether house dust-mites cause oxidative stress in patients. Products of lipid peroxidation in erythrocytes and lymphocytes were assessed by measuring malondialdehyde concentration. Our results showed that patients who had a positive skin test for dust-mite antigens and had dust-mites present in their houses (dust-mite positive) had increased erythrocyte malondialdehyde levels (62.39 [18.56] nmol/g-Hb) compared with those who were skin test positive, dust-mite negative (45.45 [10.82]) or skin test negative, dust-mite negative (42.20 [5.68]). They also had significantly higher levels of lymphocyte malondialdehyde (4.22 [0.55] nmol/g-protein) compared with those who were skin test positive, dust-mite negative (3.46 [0.29]) or skin test negative, dust-mite negative (1.25 [0.31]; p dust-mite negative/skin test positive and dust-mite negative/skin test negative patients. Increased malondialdehyde activity in lymphocytes and erythrocytes in the dust-mite positive/skin test positive group shows the presence of the oxidative stress in patients with dust-mite infestation.

  7. Desert Dust and Monsoon Rain

    Science.gov (United States)

    Lau, William K. M.; Kim, Kyu-Myong

    2014-01-01

    For centuries, inhabitants of the Indian subcontinent have know that heavy dust events brought on by strong winds occur frequently in the pre-monsoon season, before the onset of heavy rain. Yet scientists have never seriously considered the possibility that natural dust can affect monsoon rainfall. Up to now, most studies of the impacts of aerosols on Indian monsoon rainfall have focused on anthropogenic aerosols in the context of climate change. However, a few recent studies have show that aerosols from antropogenic and natural sources over the Indian subcontinent may affect the transition from break to active monsoon phases on short timescales of days to weeks. Writing in Nature Geoscience, Vinoj and colleagues describe how they have shown that desert dust aerosols over the Arabian Sea and West Asia can strenghten the summer monsoon over the Indial subcontinent in a matter of days.

  8. The effects of meteoroid streams on the lunar environment: Observations from the LADEE mission

    Science.gov (United States)

    Stubbs, Timothy; Horanyi, Mihaly; Mahaffy, Paul; Wang, Yongli; Benna, Mehdi; Elphic, Richard; Sarantos, Menelaos; Kempf, Sascha; Colaprete, Anthony; Hurley, Dana; Delory, Gregory; Glenar, David; Hermalyn, Brendan; Wooden, Diane; Szalay, Jamey

    The scientific objectives of the Lunar Atmosphere and Dust Environment Explorer (LADEE) mission are: (1) determine the composition of the lunar atmosphere, investigate processes controlling distribution and variability - sources, sinks, and surface interactions; and (2) characterize the lunar exospheric dust environment, measure spatial and temporal variability, and influences on the lunar atmosphere. Impacts on the lunar surface from meteoroid streams encountered by the Earth-Moon system can result in measurable enhancements in both the lunar atmosphere and dust environment. Here we describe the annual meteoroid streams incident at the Moon during the LADEE mission and their effects on the environment. The LADEE science payload consists of three instruments: the Ultraviolet/Visible Spectrometer (UVS) for measuring emission lines from exospheric species and scattered light from exospheric dust; the Lunar Dust Experiment (LDEX) for in situ measurement of exospheric dust; and the Neutral Mass Spectrometer (NMS) for in situ measurement of exospheric species. All three instruments are capable of detecting the effects of an encounter with a meteoroid stream. LADEE nominally has a 100-day science mission in which its retrograde equatorial orbit (inclination ≈157(°) ) will take it below 50 km altitude at periapsis near lunar sunrise. Lunar Orbit Insertion (LOI) occurred on 6 October 2013 and the current End-of-Mission (EOM) is planned for around 21 April 2014 following the lunar eclipse on 15 April 2014. The Earth-Moon system frequently encounters debris trails from comets and asteroids, which are referred to as meteoroid streams. The meteoroids in these streams have similar velocities and are on near-parallel trajectories, so when they enter the Earth's atmosphere the resulting shower of meteors appears to be emanating from a virtual point on the sky called the radiant. Meteor (and meteoroid) rates vary as a function of the Earth's position in its orbit, with an

  9. Distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in street dust from the Tokyo Metropolitan area.

    Science.gov (United States)

    Takada, H; Onda, T; Harada, M; Ogura, N

    1991-09-01

    Molecular distributions of polycyclic aromatic hydrocarbons (PAHs) in street dust samples collected from the Tokyo Metropolitan area were determined by capillary gas chromatography following HPLC fractionation. Three- to six-ring PAHs and sulfur-heterocyclics were detected. PAHs in the dusts were dominated by three and four unsubstituted ring systems with significant amounts of their alkyl homologues. PAHs were widely distributed in the streets, with concentrations (sigma COMB) of a few microgram/g dust. Automobile exhaust, asphalt, gasoline fuel, diesel fuel, tyre particles, automobile crankcase oils, and atmospheric fallout were also analysed. The PAH profile, especially the relative abundance of alkyl-PAHs and sulfur-containing heterocyclics, indicated that PAHs in the street dusts from roads carrying heavy traffic are mainly derived from automobile exhausts; dusts from residential areas have a more significant contribution from atmospheric fallout.

  10. Seasonal variability of mercury contents in street dust in Brno, Czech Republic.

    Science.gov (United States)

    Coufalík, Pavel; Zvěřina, Ondřej; Mikuška, Pavel; Komárek, Josef

    2014-10-01

    Environmental contamination by mercury carries serious risks to the biosphere. Urban agglomerations burdened with traffic are characterized by substantial dust levels, including high concentrations of pollutants bound to particulate matter. In this research, the content of particulate mercury in street dust was investigated in relation to the season and traffic intensity. In total, 80 street dust samples were collected in the centre of Brno (Czech Republic) in which total and bioaccessible mercury contents were determined. Total mercury content in the samples ranged from 0.03 to 2.67 mg/kg. The content of bioaccessible mercury was below the limit of quantification in all samples. Thus, street dust did not increase the daily mercury intake by the population in studied area. A clear trend of mercury accumulation in street dust depending on traffic intensity in the investigated streets was not observed over the whole year.

  11. METHODS OF DUST PREVENTION FROM LANDFILLS OF RAW MATERIALS AND WASTE

    Directory of Open Access Journals (Sweden)

    Jan J. Hycnar

    2017-08-01

    Full Text Available The article presents an overview of ways of solving the problem of dusting of raw materials and fine-grained waste collected on landfills. The specific physicochemical properties of loose materials and unfavorable atmospheric conditions are responsible of heavy pollution of the environment by dust, posing a threat to human health. The types of materials that are potential sources of dust pollution are presented. The methods of eliminating and limiting dusty of loose powders, often used in industry, engineering, communal and emergency situations, are discussed. Examples of domestic and foreign solutions to prevent dusting and to protect the waste deposit from erosion are shown. In conclusion, existing safety techniques have been found to be effective in preventing dusting of raw materials and waste.

  12. Atmospheric microbiology in coastal northern California during Asian dust events

    Science.gov (United States)

    Warren-Rhodes, K. A.; Griffin, D. W.

    2004-12-01

    Each year, billions of tons of dust are swept from deserts in China and Africa across the globe to the US and Caribbean. Microorganisms are likely hitchhikers aboard this aerosolized dust, with potential human health and ecological impacts. In order to investigate the presence of bacteria and fungi in dust storms from Asia, atmospheric samples for cultivatable microbiological analysis were collected during the NASA Extended- Modis Validation Experiment (EVE), occurring April 21-30, 2004 and coinciding with seasonal Asian dust storm activity. Samples were taken by Twin Otter aircraft along the coast of northern California ( ˜100 km offshore of Monterey to San Francisco). An ˜100 km horizontal leg was flown at ˜100 km altitude, typically in the marine boundary layer, followed by a vertical spiral to the dust layer (as indicated by aerosol extinction monitoring) and a second horizontal leg in the dust layer at higher altitudes (2,100-4,200 m). Air samples were taken via Venturi tube inlets with sterile Millipore filter holders outfitted with 47 mm diameter test filters connected to a vacuum pump system. Total sample time varied and was based on flight conditions and EVE objectives. Typical flow rates were 40 lpm and average sample times were ˜1hr in the marine layer and ˜30 minutes in the dust layer. Control samples for handling and contamination were also obtained. Microbial culture of the filters was conducted using sterile techniques and R2A agar, with filters incubated in the dark at room temperature and monitored for growth over a 2-week period. Fungi and bacterial colonies were further isolated on fresh plates of R2A and Tryptic Soy Broth for the purpose of cataloging/storage. No isolates were obtained from samples of dust layers at altitude. This result may be explained by: i) inadequate sample volumes to detect extremely low bacterial numbers, though sample volumes ranged from 750-2100 liters, ii) light dust layer concentrations during the sampling period

  13. An analysis of the dust deposition on solar photovoltaic modules.

    Science.gov (United States)

    Styszko, Katarzyna; Jaszczur, Marek; Teneta, Janusz; Hassan, Qusay; Burzyńska, Paulina; Marcinek, Ewelina; Łopian, Natalia; Samek, Lucyna

    2018-03-29

    Solid particles impair the performance of the photovoltaic (PV) modules. This results in power losses which lower the efficiency of the system as well as the increases of temperature which additionally decreases the performance and lifetime. The deposited dust chemical composition, concentration and formation of a dust layer on the PV surface differ significantly in reference to time and location. In this study, an evaluation of dust deposition on the PV front cover glass during the non-heating season in one of the most polluted European cities, Kraków, was performed. The time-dependent particle deposition and its correlation to the air pollution with particulate matter were analysed. Dust deposited on several identical PV modules during variable exposure periods (from 1 day up to 1 week) and the samples of total suspended particles (TSP) on quartz fibre filters using a low volume sampler were collected during the non-heating season in the period of 5 weeks. The concentration of TSP in the study period ranged between 12.5 and 60.05 μg m -3 while the concentration of PM10 observed in the Voivodeship Inspectorate of Environmental Protection traffic station, located 1.2 km from the TSP sampler, ranged from 14 to 47 μg m -3 . It was revealed that dust deposition density on a PV surface ranged from 7.5 to 42.1 mg m -2 for exposure periods of 1 day while the measured weekly dust deposition densities ranged from 25.8 to 277.0 mg m -2 . The precipitation volume and its intensity as well as humidity significantly influence the deposited dust. The rate of dust accumulation reaches approximately 40 mg m -2 day -1 in the no-precipitation period and it was at least two times higher than fluxes calculated on the basis of PM10 and TSP concentrations which suggest that additional forces such as electrostatic forces significantly influence dust deposition.

  14. Temperature and current data collected as part of the CLIvar MOde Water Dynamic Experiment (CLIMODE) mooring data from 2005-11 to 2007-11 in the North Atlantic, south-east of the Gulf Stream (NCEI Accession 0127259)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Two years of temperature, salinity, current, and nutrient data were collected on four subsurface moorings as part of a two-year field component of the CLIMODE...

  15. Direct Characterization of Comets and Asteroids via Cosmic Dust Analysis from the Deep Space Gateway

    Science.gov (United States)

    Fries, M.; Fisher, K.

    2018-01-01

    The Deep Space Gateway (DSG) may provide a platform for direct sampling of a large number of comets and asteroids, through employment of an instrument for characterizing dust from these bodies. Every year, the Earth traverses through debris streams of dust and small particles from comets and asteroids in Earth-crossing orbits, generating short-lived outbursts of meteor activity commonly known as "meteor showers" (Figure 1). The material in each debris stream originates from a distinct parent body, many of which have been identified. By sampling this material, it is possible to quantitatively analyze the composition of a dozen or more comets and asteroids (See Figure 2, following page) without leaving cislunar space.

  16. The double-dust solution

    CERN Document Server

    Krämer, Dietrich

    2002-01-01

    An exact solution describing the static gravitational field produced by the superposition of two dust beams of equal mass density but opposite propagation direction is given in a closed form. In particular, the cylindrically symmetric situation is considered in which the two dust components move on trajectories screwing around the axis. In this case, the solution can be matched to the Levi-Civita external vacuum solution at any value of the radial coordinate. The axis is regular and the mass density is positive everywhere in the interior region of the global solution. The dominant energy condition is satisfied.

  17. Intergalactic dust and quasar distribution

    International Nuclear Information System (INIS)

    Soltan, A.

    1979-01-01

    Non-homogeneous intergalactic extinction may considerably affect the quasar distribution. Especially samples of quasars isolated on the basis of B-V colours are subject to this phenomenon. Apparent grouping and close pairs of quasars reported in the literature may be a result of intergalactic dust. Using surface distribution of faint blue objects selected by Hawkins and Reddish it is estimated that intergalactic extinction in B should reach approximately 1 mag out to the redshift of approximately 1. This is slightly larger than predicted by theory and comparable to the mean dust density derived from observations. (Author)

  18. Investigating methods of stream planform identification

    Science.gov (United States)

    Lohberg, M. M.; Lusk, K.; Miller, D.; Stonedahl, F.; Stonedahl, S. H.

    2013-12-01

    Stream planforms are used to map scientific measurements, estimate volumetric discharge, and model stream flow. Changes in these planforms can be used to quantify erosion and water level fluctuations. This research investigated five cost-effective methods of identifying stream planforms: (1) consumer-grade digital camera GPS (2) multi-view stereo 3D scene reconstruction (using Microsoft Photosynth (TM)) (3) a cross-sectional measurement approach (4) a triangulation-based measurement approach and (5) the 'square method' - a novel photogrammetric procedure which involved floating a large wooden square in the stream, photographing the square and banks from numerous angles and then using the square to correct for perspective and extract the outline (using custom post-processing software). Data for each of the five methods was collected at Blackhawk Creek in Davenport, Iowa. Additionally we placed 30 control points near the banks of the stream and measured 88 lengths between these control points. We measured or calculated the locations of these control points with each of our five methods and calculated the average percent error associated with each method using the predicted control point locations. The effectiveness of each method was evaluated in terms of accuracy, affordability, environmental intrusiveness, and ease of use. The camera equipped with GPS proved to be a very ineffective method due to an extremely high level of error, 289%. The 3D point cloud extracted from Photosynth was missing markers for many of the control points, so the error calculation (which yielded 11.7%) could only be based on five of the 88 lengths and is thus highly uncertain. The two non-camera methods (cross-sectional and triangulation measurements) resulted in low percent error (2.04% and 1.31% respectively) relative to the control point lengths, but these methods were very time consuming, exhausting, and only provided low resolution outlines. High resolution data collection would

  19. Sedgeunkedunk Stream channel geometry from 2007-08-15 to 2016-03-30 (NCEI Accession 0152486)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — We are collecting stream channel geometry and bed sediment grain size distribution data at Sedgeunkedunk stream to evaluate physical habitat changes associated with...

  20. Sedgeunkedunk stream bed sediment particle diameter from 2007-08-15 to 2016-03-30 (NCEI Accession 0152487)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — We are collecting stream channel geometry and bed sediment grain size distribution data at Sedgeunkedunk stream to evaluate physical habitat changes associated with...

  1. Species diversity of house dust mites in Beijing, China.

    Science.gov (United States)

    Sun, Jin-Lu; Shen, Lian; Chen, Jun; Yu, Jin-Miao; Yin, Jia

    2013-01-01

    Even though house dust mites are one of the most important allergens, there have been few studies in China for their identification and diversity. In this study, we reported that Dermatophagoides siboney was found for the first time in Beijing, China, in a temperate zone and it was also the first reported in Asia. This survey of mite prevalence was carried out in several districts of Beijing, a city of thirty million people. House dust samples were collected from 38 homes of mite-allergic patients who visited our Allergy Department from December 2008 to January 2010. Out of 345 house dust samples collected, 64% contained mites. Dermatophagoides farinae was the predominant species in the mite population found and Dermatophagoides pteronyssinus was second, and Dermatophagoides siboney was the third. The positive rates of samples were higher in single-story homes and lower buildings. The seasonal density distribution of house dust mites showed the highest mite concentration in September through October, followed by May through July, December to next January; and lowest in March and November.

  2. Heavy metal concentration of settled surface dust in residential building

    International Nuclear Information System (INIS)

    Nor Aimi abdul Wahab; Fairus Muhamad Darus; Norain Isa; Siti Mariam Sumari; Nur Fatihah Muhamad Hanafi

    2012-01-01

    The concentrations of heavy metals (Cu, Ni, Pb and Zn) in settled surface dust were collected from nine residential buildings in different areas in Seberang Prai Tengah District, Pulau Pinang. The samples of settled surface dust were collected in 1 m 2 area by using a polyethylene brush and placed in the dust pan by sweeping the living room floor most accessible to the occupants. Heavy metals concentrations were determined by using inductively coupled plasma optical emission spectrometer (ICP-OES) after digestion with nitric acid and sulphuric acid. The results show that the range of heavy metals observed in residential buildings at Seberang Prai Tengah were in the range of 2.20-14.00 mg/ kg, 1.50-32.70 mg/ kg, 1.50-76.80 mg/ kg and 14.60-54.40 mg/ kg for Cu, Ni, Pb and Zn respectively. The heavy metal concentration in the investigated areas followed the order: Pb > Zn > Ni > Cu. Statistical analysis indicates significant correlation between all the possible pairs of heavy metal. The results suggest a likely common source for the heavy metal contamination, which could be traced most probably to vehicular emissions, street dust and other related activities. (author)

  3. The Circumstellar Disk HD 169142: Gas, Dust, and Planets Acting in Concert?

    Science.gov (United States)

    Pohl, A.; Benisty, M.; Pinilla, P.; Ginski, C.; de Boer, J.; Avenhaus, H.; Henning, Th.; Zurlo, A.; Boccaletti, A.; Augereau, J.-C.; Birnstiel, T.; Dominik, C.; Facchini, S.; Fedele, D.; Janson, M.; Keppler, M.; Kral, Q.; Langlois, M.; Ligi, R.; Maire, A.-L.; Ménard, F.; Meyer, M.; Pinte, C.; Quanz, S. P.; Sauvage, J.-F.; Sezestre, É.; Stolker, T.; Szulágyi, J.; van Boekel, R.; van der Plas, G.; Villenave, M.; Baruffolo, A.; Baudoz, P.; Le Mignant, D.; Maurel, D.; Ramos, J.; Weber, L.

    2017-11-01

    HD 169142 is an excellent target for investigating signs of planet-disk interaction due to previous evidence of gap structures. We perform J-band (˜1.2 μm) polarized intensity imaging of HD 169142 with VLT/SPHERE. We observe polarized scattered light down to 0.″16 (˜19 au) and find an inner gap with a significantly reduced scattered-light flux. We confirm the previously detected double-ring structure peaking at 0.″18 (˜21 au) and 0.″56 (˜66 au) and marginally detect a faint third gap at 0.″70-0.″73 (˜82-85 au). We explore dust evolution models in a disk perturbed by two giant planets, as well as models with a parameterized dust size distribution. The dust evolution model is able to reproduce the ring locations and gap widths in polarized intensity but fails to reproduce their depths. However, it gives a good match with the ALMA dust continuum image at 1.3 mm. Models with a parameterized dust size distribution better reproduce the gap depth in scattered light, suggesting that dust filtration at the outer edges of the gaps is less effective. The pileup of millimeter grains in a dust trap and the continuous distribution of small grains throughout the gap likely require more efficient dust fragmentation and dust diffusion in the dust trap. Alternatively, turbulence or charging effects might lead to a reservoir of small grains at the surface layer that is not affected by the dust growth and fragmentation cycle dominating the dense disk midplane. The exploration of models shows that extracting planet properties such as mass from observed gap profiles is highly degenerate. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO program 095.C-0273.

  4. Multidisciplinary studies of the dust storm that affected Sydney in September 2009

    Science.gov (United States)

    De Deckker, P.

    2012-04-01

    A major dust storm transgressed over southeastern Australia in September 2009 and continued as far as northern Queensland [to the north], New Zealand and New Caledonia [to the east] . We analysed samples of the dust for organic compounds, its microbiological composition, pollen, trace and rare earth elements as well as Sr and Nd isotopes. Grain size analysis was also performed on some of the samples. We also obtained information on the meteorological conditions that led to the large dust plume and its pathway. Our geochemical fingerprinting allowed us to determine the origin of the dust, and this was confirmed by meteorological observations and satellite imagery. As the pathway of the dust plume went over the city of Canberra, located to the southwest of Sydney, we were able to collect samples of dust that fell with rain, and the surprise was that the geochemical composition of the dust varied with time [and dust fall], identifying that as the dust plume transgressed over the landscape, it picked up additional material that was compositionally different from its point of origin. We also compared our data with those obtained from another major dust event that affected Canberra in October 2002, and a number of important differences are noted, particularly with respect of the microbiological composition of the dust, and its chemical composition. Collaborators on this project are: Chris Munday and Gwen Allison [microbiology]: Research School of Biology, ANU; Jochen Brocks and Janet Hope [organic chemistry] and Marc Norman [inorganic geochemistry]: Research School of Earth Sciences, ANU; Tadhg O'Loingsigh and Nigel Tapper [meteorology, satellite imagery] and Sander van der Kaars [palynology]: Geography and Environmental Science, Monash University; and J.-B. Stuut [grain size analysis], NIOZ.

  5. [Effect of lunar dust on humans: -lunar dust: regolith-].

    Science.gov (United States)

    Morimoto, Yasuo; Miki, Takeo; Higashi, Toshiaki; Horie, Seichi; Tanaka, Kazunari; Mukai, Chiaki

    2010-09-01

    We reviewed the effect of lunar dust (regolith) on humans by the combination of the hazard/exposure of regolith and microgravity of the moon. With regard to the physicochemical properties of lunar dust, the hazard-related factors are its components, fibrous materials and nanoparticles. Animal exposure studies have been performed using a simulant of lunar dust, and it was speculated that the harmful effects of the simulant lies between those of crystalline silica and titanium dioxide. Fibrous materials may not have a low solubility judging from their components. The nanoparticles in lunar dust may have harmful potentials from the view of the components. As for exposure to regolith, there is a possibility that particles larger than ones in earth (1 gravity) are respirable. In microgravity, 1) the deposition of particles of less than 1 µm in diameter in the human lung did not decrease, 2) the functions of macrophages including phagocytosis were suppressed, 3) pulmonary inflammation was changed. These data on hazard/exposure and microgravity suggest that fine and ultrafine particles in regolith may have potential hazards and risks for humans.

  6. Dust Storms: Why Are Dust Storms a Concern?

    Science.gov (United States)

    ... or coccidioidomycosis. These spores live in the desert soil of semi-arid areas and are native to the ... this topic. Web Links from MedlinePlus (National Library of Medicine) Air Pollution Asthma Valley Fever More Links Dust Control On ...

  7. The global distribution of mineral dust

    International Nuclear Information System (INIS)

    Tegen, I; Schepanski, K

    2009-01-01

    Dust aerosol particles produced by wind erosion in arid and semi arid regions affect climate and air quality, but the magnitude of these effects is largely unquantified. The major dust source regions include the Sahara, the Arabian and Asian deserts; global annual dust emissions are currently estimated to range between 1000 and 3000 Mt/yr. Dust aerosol can be transported over long distances of thousands of kilometers, e.g. from source regions in the Saharan desert over the North Atlantic, or from the Asian deserts towards the Pacific Ocean. The atmospheric dust load varies considerably on different timescales. While dust aerosol distribution and dust effects are important on global scales, they strongly depend on dust emissions that are controlled on small spatial and temporal scales.

  8. The global distribution of mineral dust

    Energy Technology Data Exchange (ETDEWEB)

    Tegen, I; Schepanski, K [Leibniz Institute for Tropospheric Research, Leipzig (Germany)], E-mail: itegen@mail.tropos.de

    2009-03-01

    Dust aerosol particles produced by wind erosion in arid and semi arid regions affect climate and air quality, but the magnitude of these effects is largely unquantified. The major dust source regions include the Sahara, the Arabian and Asian deserts; global annual dust emissions are currently estimated to range between 1000 and 3000 Mt/yr. Dust aerosol can be transported over long distances of thousands of kilometers, e.g. from source regions in the Saharan desert over the North Atlantic, or from the Asian deserts towards the Pacific Ocean. The atmospheric dust load varies considerably on different timescales. While dust aerosol distribution and dust effects are important on global scales, they strongly depend on dust emissions that are controlled on small spatial and temporal scales.

  9. Infrared Observations of Cometary Dust and Nuclei

    Science.gov (United States)

    Lisse, Carey

    2004-01-01

    This bibliography lists citations for publications published under the grant. Subjects of the publications include cometary dust, instellar and interplanetary dust, comet nuclei and comae, Comet Hale-Bopp, infrared observations of comets, mass loss, and comet break-up.

  10. Electrostatic Dust Detector with Improved Sensitivity

    International Nuclear Information System (INIS)

    Boyle, D.P.; Skinner, C.H.; Roquemore, A.L.

    2008-01-01

    Methods to measure the inventory of dust particles and to remove dust if it approaches safety limits will be required in next-step tokamaks such as ITER. An electrostatic dust detector, based on a fine grid of interlocking circuit traces, biased to 30 or 50 V, has been developed for the detection of dust on remote surfaces in air and vacuum environments. Gaining operational experience of dust detection on surfaces in tokamaks is important, however the level of dust generated in contemporary short-pulse tokamaks is comparatively low and high sensitivity is necessary to measure dust on a shot-by-shot basis. We report on modifications in the detection electronics that have increased the sensitivity of the electrostatic dust detector by a factor of up to 120, - a level suitable for measurements on contemporary tokamaks.

  11. MODELING DUST IN THE MAGELLANIC CLOUDS

    Energy Technology Data Exchange (ETDEWEB)

    Zonca, Alberto; Casu, Silvia; Mulas, Giacomo; Aresu, Giambattista [INAF—Osservatorio Astronomico di Cagliari, Via della Scienza 5, I-09047 Selargius (Italy); Cecchi-Pestellini, Cesare, E-mail: azonca@oa-cagliari.inaf.it, E-mail: silvia@oa-cagliari.inaf.it, E-mail: gmulas@oa-cagliari.inaf.it, E-mail: garesu@oa-cagliari.inaf.it, E-mail: cecchi-pestellini@astropa.inaf.it [INAF—Osservatorio Astronomico di Palermo, P.za Parlamento 1, I-90134 Palermo (Italy)

    2015-09-01

    We model the extinction profiles observed in the Small and Large Magellanic clouds with a synthetic population of dust grains consisting of core-mantle particles and a collection of free-flying polycyclic aromatic hydrocarbons (PAHs). All different flavors of the extinction curves observed in the Magellanic Clouds (MCs) can be described by the present model, which has been previously (successfully) applied to a large sample of diffuse and translucent lines of sight in the Milky Way. We find that in the MCs the extinction produced by classical grains is generally larger than absorption by PAHs. Within this model, the nonlinear far-UV rise is accounted for by PAHs, whose presence in turn is always associated with a gap in the size distribution of classical particles. This hints either at a physical connection between (e.g., a common cause for) PAHs and the absence of middle-sized dust particles or the need for an additional component in the model that can account for the nonlinear far-UV rise without contributing to the UV bump at ∼217 nm such as, e.g., nanodiamonds.

  12. Analysis of dust removal equipment used in the manufacture of soluble powders

    Directory of Open Access Journals (Sweden)

    E. A. Rudyka

    2016-01-01

    Full Text Available Analyzed the system of drying plant air cleaning, specializing in the production of food powders, dust emission identified place in the shop drying in the production of soluble dietary powders, the parameters of the dryer exhaust coolant, analyzed the properties of the product, as well as determined the effectiveness of the use of air purification equipment. Analyzed used at the enterprise two-stage cleaning system. As a first purification stage conical cyclone installed as a second stage purification analyzed dust collector is proposed with internal circulation of the liquid. It was found that the drying of the powder contained in the emissions of a large proportion of the fine fraction of dust. Several studies have been conducted with this food dust. It was found that the collection efficiency in the cyclone ranged from 68% (tea dust to 92% (dust kvass wort. Analyzing the data obtained indicated that the efficiency of cleaning exhaust coolant is heavily dependent on the food composition of disperse dust, and less than 10 microns particles is insufficient. It is proposed to use for cleaning the coolant wet dust collector with internal circulation of the liquid. The regularities of change of concentration of solids in the cleaning liquid, its viscosity and surface tension with increasing operating time since the start of the dust collector. It is found that increasing the concentration of solids in the cleaning liquid increases with the operating time of the machine since the start-up leads to changes in surface tension and viscosity of the liquid. It is shown that the effective dust collection in the machine decreases as the viscosity of the working fluid. Both theoretically and experimentally established patterns may be used when calculating the optimum specific liquid flow to provide effective cleaning and releases the trapped product return process cycle.

  13. Particle size and metals concentrations of dust from a paint manufacturing plant.

    Science.gov (United States)

    Huang, Siew Lai; Yin, Chun-Yang; Yap, Siaw Yang

    2010-02-15

    In this study, the particle size distribution and concentration of metallic elements of solvent- and water-based paint dust from bulk dust collected from dust-collecting hoppers were determined. The mean particle size diameter over a 12-week sampling period was determined using a particle size analyzer. The metals composition and concentration of the dust were determined via acid digestion technique followed by concentration analysis using inductively coupled plasma. The volume weighted mean particle diameters were found to be 0.941+/-0.016 and 8.185+/-0.201 microm for solvent- and water-based paint dust, respectively. The mean concentrations of metals in solvent-based paint dust were found to be 100+/-20.00 microg/g (arsenic), 1550+/-550.00 microg/g (copper), 15,680+/-11,780.00 microg/g (lead) and 30,460+/-10,580.00 microg/g (zinc) while the mean concentrations of metals in water-based paint dust were found to be 20.65+/-6.11 microg/g (arsenic), 9.14+/-14.65 microg/g (copper), 57.46+/-22.42 microg/g (lead) and 1660+/-1260 microg/g (zinc). Both paint dust types could be considered as hazardous since almost all of the dust particles were smaller than 10 microm. Particular emphasis on containment of solvent-based paint dust particles should be given since it was shown that they were very fine in size (<1 microm) and had high lead and zinc concentrations.

  14. Basis for criteria for exemption of decommissioning waste: reprocessing of dust from recycling of steel

    International Nuclear Information System (INIS)

    Elert, M.; Wiborgh, M.

    1992-06-01

    This study is a part of a larger study with the purpose to provide the authority concerned, the Swedish Radiation Protection Institute (SSI), with technical background material needed for future decisions concerning exemption levels for recycling and disposal of material originating from decommissioned nuclear power reactors. The dismantling of nuclear power reactors will give rise to large amounts of steel scrap with a very low activity concentration. It is of interest to exempt this material from regulatory control in order to make recycling possible. During the melting of steel scrap dust will be formed which is collected in the off-gas cleaning system of the furnace. Radionuclides may be enriched in this dust, and thereby obtain a higher activity concentration than the melted scrap. Presently, there is a strong interest to reprocess these dusts with the objectives to recover valuable metals and to reduce the amounts of waste harmful to the environment. During the reprocessing of dusts collected from the melting process a further redistribution and reconcentration of radionuclides may occur. In this report the treatment of dust from steel melting is described, the potential reconcentration of radionuclides is analyzed, and the potential radiological consequences are estimated. The study has focussed on the reprocessing of dust with the plasma method used at ScanDust in Sweden, and with the Waelz process used in, for example Spain and Germany. Various factors as economical, political and future developments of dust treatment and steel processes will determine the amounts of dusts produced and also to what degree dust will be reprocessed in the future. (au)

  15. Perchlorate in indoor dust and human urine in China: contribution of indoor dust to total daily intake.

    Science.gov (United States)

    Zhang, Tao; Chen, Xiaojia; Wang, Dou; Li, Rudan; Ma, Yufang; Mo, Weiwen; Sun, Hongwen; Kannan, Kurunthachalam

    2015-02-17

    Perchlorate is used in fireworks and China is the largest fireworks producer and consumer in the world. Information regarding human exposure to perchlorate is scarce in China, and exposure via indoor dust ingestion (EDI indoor dust) has rarely been evaluated. In this study, perchlorate was found in indoor dust (detection rate: 100%, median: 47.4 μg/g), human urine (99%, 26.2 ng/mL), drinking water (100%, 3.99 ng/mL), and dairy milk (100%, 12.3 ng/mL) collected from cities that have fireworks manufacturing areas (Yueyang and Nanchang) and in cities that do not have fireworks manufacturing industries (Tianjin, Shijiazhuang, Yuxi and Guilin) in China. In comparison with perchlorate levels reported for other countries, perchlorate levels in urine samples from fireworks sites and nonfireworks sites in China were higher. Median indoor dust perchlorate concentrations were positively correlated (r = 0.964, p < 0.001) with outdoor dust perchlorate levels reported previously. The total daily intake (EDI total) of perchlorate, estimated based on urinary levels, ranged from 0.090 to 27.72 μg/kg body weight (bw)/day for all studied participants; the percentage of donors who had EDI total exceeding the reference dose (RfD) recommended by the United States Environmental Protection Agency (US EPA) was 79%, 48%, and 25% for toddlers (median: 1.829 μg/kg bw/day), adults (0.669 μg/kg bw/day), and children (median: 0.373 μg/kg bw/day), respectively. Toddlers (0.258 μg/kg bw/day) had the highest median EDI indoor dust, which was 2 to 5 times greater than the EDI indoor dust calculated for other age groups (the range of median values: 0.044 to 0.127 μg/kg bw/day). Contribution of indoor dust to EDItotal was 26%, 28%, and 7% for toddlers, children, and adults, respectively. Indoor dust contributed higher percentage to EDI total than that by dairy milk (0.5-5%).

  16. Investigations into detonations of coal dust suspensions in oxygen-nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, D.; Fearnley, P.; Nettleton, M.

    1987-03-01

    The effect of particle size (practically monodispersed), volatile content and composition of gaseous oxygen-nitrogen mixtures on initiating flame acceleration rates in coal dust suspensions is investigated experimentally. Description is given of apparatus, material used and experiments carried out. The authors discusses: microwave interferograms, pressure oscillograms for various oxygen-nitrogen mixtures; development of ionization front speed in relation to distance from diaphragm; effect of composition on shock wave advance rates. It is concluded that: microwave interferometry can successfully be used in recording initiation of coal dust suspension detonations; ignition of confined coal dust suspensions by shock waves originated by detonation front in stoichiometric oxyacetylene mixtures can be explained by heating of coal particles in shock compression stream to ignition temperature (1000 K) by combined convection and radiation heat transfer. 16 refs.

  17. Comet 'Bites the Dust' Around Dead Star

    Science.gov (United States)

    2006-01-01

    of dust. The data also demonstrate that this dust contains some of the same types of minerals found in comet Hale-Bopp. The findings tell a possible tale of solar system survival. Though the dust seen by Spitzer is likely from a comet that recently perished, its presence suggests that an icy distant ring of comets may still orbit the dead star. These data were collected by Spitzer's infrared spectrometer, an instrument that cracks light open like a geode, revealing its coveted components. In this spectrum, light from the white dwarf is on the left, at ultraviolet and visible wavelengths. The spectrum on the right, at infrared wavelengths longer than about 2 microns, shows much more light than can be explained by a white dwarf alone. The bump seen around a wavelength of 10 microns offers a clue to the source of this excess infrared light. It signifies the presence of silicate minerals, which are found in our own solar system on Earth, in sandy beaches, and in comets and asteroids. These silicate grains appear to be very small like those in comets, so astronomers favor the theory that a comet recently broke apart around the dead star.

  18. Lidar Observations During the Saharan Mineral Dust Experiments 1 and 2

    Science.gov (United States)

    Tesche, M.; Althausen, D.; Ansmann, A.; Engelmann, R.; Müller, D.; Freudenthaler, V.; Groß, S.

    2009-04-01

    Polarization Raman lidar measurements at various wavelengths were performed during the Saharan Mineral Dust Experiment (SAMUM) 1 and 2 to study the optical properties of desert dust aerosol. SAMUM 1 at the airport of Ouarzazate (30.9∘ N, 6.9∘ W, 1133 m height above sea level, asl) in southern Morocco was devoted to the investigation fresh desert dust. SAMUM 2 at the airport of Praia (15.0∘ N, 23.5∘ W, 75 m height asl), Cape Verde focussed on the characterization of a mixture of aged dust from North Africa and biomass burning aerosol from Central Africa. A large dataset of optical, microphysical, and radiative properties of the respective aerosol types has been collected. From the BERTHA measurements at Ouarzazare during May-June 2006 multiwavelengths information of backscatter and extinction coefficients, and the resulting lidar ratio were derived. The statistical analysis of the SAMUM 1 dataset reveals that the dust layer depth typically reaches 4-6 km height asl, sometimes even 7 km asl. A vertically inhomogeneous dust plume with internal dust layers was usually observed in the morning before the evolution of the boundary layer starts. The Saharan dust layer was well-mixed in the early evening. AERONET observations of these layers showed an optical thickness ranging from 0.2-0.8 (at 500 nm, mean value 0.32).

  19. The effects of transported Asian dust on the composition and concentration of ambient fungi in Taiwan

    Science.gov (United States)

    Chao, H. Jasmine; Chan, Chang-Chuan; Rao, Carol Y.; Lee, Chung-Te; Chuang, Ying-Chih; Chiu, Yueh-Hsiu; Hsu, Hsiao-Hsien; Wu, Yi-Hua

    2012-03-01

    This study was conducted to evaluate the effects of transported Asian dust and other environmental parameters on the levels and compositions of ambient fungi in the atmosphere of northern Taiwan. We monitored Asian dust events in Taipei County, Taiwan from January 2003 to June 2004. We used duplicate Burkard portable air samplers to collect ambient fungi before, during, and after dust events. Six transported Asian dust events were monitored during the study period. Elevated concentrations of Aspergillus ( A. niger, specifically), Coelomycetes, Rhinocladiella, Sporothrix and Verticillium were noted ( p < 0.05) during Asian dust periods. Botryosporium and Trichothecium were only recovered during dust event days. Multiple regression analysis showed that fungal levels were positively associated with temperature, wind speed, rainfall, non-methane hydrocarbons and particulates with aerodynamic diameters ≤10 μm (PM10), and negatively correlated with relative humidity and ozone. Our results demonstrated that Asian dust events affected ambient fungal concentrations and compositions in northern Taiwan. Ambient fungi also had complex dynamics with air pollutants and meteorological factors. Future studies should explore the health impacts of ambient fungi during Asian dust events, adjusting for the synergistic/antagonistic effects of weather and air pollutants.

  20. Dust Measurements Onboard the Deep Space Gateway

    Science.gov (United States)

    Horanyi, M.; Kempf, S.; Malaspina, D.; Poppe, A.; Srama, R.; Sternovsky, Z.; Szalay, J.

    2018-02-01

    A dust instrument onboard the Deep Space Gateway will revolutionize our understanding of the dust environment at 1 AU, help our understanding of the evolution of the solar system, and improve dust hazard models for the safety of crewed and robotic missions.

  1. Molecules and dust in Cassiopeia A

    DEFF Research Database (Denmark)

    Biscaro, Chiara; Cherchneff, Isabelle

    2016-01-01

    We study the dust evolution in the supernova remnant Cassiopeia A. We follow the processing of dust grains that formed in the Type II-b supernova ejecta by modelling the sputtering of grains. The dust is located in dense ejecta clumps that are crossed by the reverse shock. We also investigate fur...

  2. Properties of interstellar dust in reflection nebulae

    International Nuclear Information System (INIS)

    Sellgren, K.

    1988-01-01

    Observations of interstellar dust in reflection nebulae are the closest analog in the interstellar medium to studies of cometary dust in our solar system. The presence of a bright star near the reflection nebula dust provides the opportunity to study both the reflection and emission characteristics of interstellar dust. At 0.1 to 1 micrometer, the reflection nebula emission is due to starlight scattered by dust. The albedo and scattering phase function of the dust is determined from observations of the scattered light. At 50 to 200 micrometers, thermal emission from the dust in equilibrium with the stellar radiation field is observed. The derived dust temperature determines the relative values of the absorption coefficient of the dust at wavelengths where the stellar energy is absorbed and at far infrared wavelengths where the absorbed energy is reradiated. These emission mechanisms directly relate to those seen in the near and mid infrared spectra of comets. In a reflection nebula the dust is observed at much larger distances from the star than in our solar system, so that the equilibrium dust temperature is 50 K rather than 300 K. Thus, in reflection nebulae, thermal emission from dust is emitted at 50 to 200 micrometer

  3. House dust extracts contain potent immunological adjuvants

    NARCIS (Netherlands)

    Beukelman, C.J.; Dijk, H. van; Aerts, P.C.; Rademaker, P.M.; Berrens, L.; Willers, J.M.N.

    1987-01-01

    A crude aqueous extract of house dust and two house dust subfractions were tested for adjuvant activity in a sensitivity assay performed in mice. Evidence is presented that house dust contains at least two potent immunological adjuvants. One of these, present in both subfractions, was probably

  4. Stochastic charging of dust grains in protoplanetary disks

    Science.gov (United States)

    Sharmin Ashrafi, Khandaker; Esparza, Samuel; Xiang, Chuchu; Matthews, Lorin; Carballido, Augusto; Hyde, Truell

    2017-06-01

    Micron-sized dust grains are abundant in the early stages of protoplanetary disks. Not only do such solid particles provide the seeds for planetesimal formation through collisional growth and collective effects, they also modify the overall ionization levels of the surrounding plasma through the accumulation of charge. If the local dust density is large enough that charge is removed from the nebular gas through deposition on grain surfaces, magnetic fields can detach from the gas making the MRI process inoperative. For highly porous dust aggregates, MRI quenching can become even more efficient since porous aggregates accumulate charge more efficiently than do compact spherical grains having the same mass. The primary goal of this work is to develop a numerical model of dust coagulation and charging in a magnetized protoplanetary disk to answer the question: What role does the porosity and/or electrical charge state of dust aggregates play in the magnetohydrodynamic (MHD) structure of protoplanetary disks? The collisional charging of a grain is affected by its surface area and morphology. Here we compare the electron and ion currents incident on micron and submicron aggregate grains made of spherical monomers to the currents incident on spherical grains of equivalent mass. The electrons and ions are absorbed on the dust grain surface at random times; as a result charge fluctuates stochastically. We calculate the average charge and charge probability distribution for (i) aggregates composed of monomers of 10 nm, 20 nm and 50 nm monomers with an effective aggregate radius of 0.1 m, and (ii) aggregates consisting of up to 100 monomers with monomer radius of 0.1 micron. The implications of our results for non-ideal magnetohydrodynamics in protoplanetary disks are briefly discussed in terms of the effect of disk ionization fraction and chemical networks.

  5. Flame retardant associations between children's handwipes and house dust.

    Science.gov (United States)

    Stapleton, Heather M; Misenheimer, John; Hoffman, Kate; Webster, Thomas F

    2014-12-01

    Polybrominated diphenyl ether (PBDE), flame retardants (FRs) have been ubiquitously detected at high concentrations in indoor environments; however, with their recent phase-out, more attention is being focused on measurements of exposure to alternative FRs such as organophosphate FRs (OPFRs). In our previous research, we found that PBDE residues measured on children's handwipes were a strong predictor of serum PBDE levels. Here we build upon this research to examine longitudinal changes in PBDEs in indoor dust and children's handwipes, and explore the associations between handwipes and dust for alternative FRs. Children from our previous study were re-contacted after approximately two years and new samples of indoor dust and handwipes were collected. PBDE dust-levels were significantly correlated between two different sampling rounds separated by two years; however, PBDE levels in handwipes were not correlated, perhaps suggesting that the sources of PBDEs remained relatively constant in the home, but that behavioral differences in children are changing with age and influencing handwipe levels. OPFRs [i.e. tris(1,3-dichloroisopropyl) phosphate (TDCPP), tris(2-chloroethyl) phosphate (TCEP), tris(2-chloroisopropyl) phosphate (TCIPP)], 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB, also known as TBB), di(2-ethylhexyl) tetrabromophthalate (BEH-TEBP, also known as TBPH), and 1,2,5,6,9,10-hexabromocyclododecane (HBCD) were also ubiquitously detected in house dust samples and geometric mean levels were similar to PBDE levels, or higher in the case of the OPFRs. Significant associations between handwipes and house dust were observed for these alternative FRs, particularly for EH-TBB (rs=0.54; p5 times d(-1)) was associated with lower FR levels in handwipes. Overall these data suggest that exposure to these alternative FRs will be similar to PBDE exposure, and the influence of hand-to-mouth behavior in children's exposure needs to be further examined to better estimate

  6. 78 FR 45566 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Coal Mine...

    Science.gov (United States)

    2013-07-29

    ... for OMB Review; Comment Request; Coal Mine Dust Sampling Devices ACTION: Notice. SUMMARY: The... information collection request (ICR) titled, ``Coal Mine Dust Sampling Devices,'' to the Office of Management...) determine the concentration of respirable dust in coal mines. CPDMs must be designed and constructed for...

  7. Concentrations of selected constituents in surface-water and streambed-sediment samples collected from streams in and near an area of oil and natural-gas development, south-central Texas, 2011-13

    Science.gov (United States)

    Opsahl, Stephen P.; Crow, Cassi L.

    2014-01-01

    During 2011–13, the U.S. Geological Survey, in cooperation with the San Antonio River Authority and the Guadalupe-Blanco River Authority, analyzed surface-water and streambed-sediment samples collected from 10 sites in the San Antonio River Basin to provide data for a broad range of constituents that might be associated with hydraulic fracturing and the produced waters that are a consequence of hydraulic fracturing. Among surface-water samples, all sulfide concentrations were less than the method detection limit of 0.79 milligrams per liter. Four glycols—diethylene glycol, ethylene glycol, propylene glycol, and triethylene glycol—were analyzed for in surface-water samples collected for this study, and none were detected. Of the 91 semivolatile organic compounds analyzed for this study, there were six detections, all but one of which were in storm-runoff samples. The base-flow sample collected at the San Antonio River at Goliad, Tex. (SAR Goliad), site contained bis(2-ethylhexyl) phthalate, a plasticizer in polyvinyl chloride and a constituent in hydraulic fracturing fluids. The storm-runoff samples collected at the San Antonio River near Elmendorf, Tex. (SAR Elmendorf), and Ecleto Creek at County Road 326 near Runge, Tex. (Ecleto 2), sites also contained bis(2-ethylhexyl) phthalate. The storm-runoff sample collected at the SAR Elmendorf site contained the plasticizer diethyl phthalate. Both storm-runoff samples collected at the Ecleto Creek near Runge, Tex. (Ecleto 1), and Ecleto 2 sites contained benzyl alcohol, a solvent commonly used in paints. Of the 67 volatile organic compounds analyzed in this study, there were a total of six detections, all of which were in base-flow samples. The surface-water sample collected at the SAR Elmendorf site contained bromodichloromethane, dibromochloromethane, and trichloromethane, all of which are disinfection byproducts associated with the chlorination of municipal water supplies and of treated municipal wastewater. The

  8. Iron content and solubility in dust from high-alpine snow along a north-south transect of High Asia

    OpenAIRE

    Guangjian Wu; Chenglong Zhang; Zhongqin Li; Xuelei Zhang; Shaopeng Gao

    2012-01-01

    This study describes the dissolved and insoluble iron fraction of dust (mineral aerosol) in high-alpine snow samples collected along a north-south transect across High Asia (Eastern Tien Shan, Qilian Shan, and Southern Tibetan Plateau). This dust provides the basic chemical properties of mid- and high-level tropospheric Asian dust that can supply the limiting iron nutrient for phytoplankton growth in the North Pacific. The iron content in Asian dust averages 4.95% in Eastern Tien Shan, 3.38–5...

  9. Re-Meandering of Lowland Streams

    DEFF Research Database (Denmark)

    Pedersen, Morten Lauge; Kristensen, Klaus Kevin; Friberg, Nikolai

    2014-01-01

    We evaluated the restoration of physical habitats and its influence on macroinvertebrate community structure in 18 Danish lowland streams comprising six restored streams, six streams with little physical alteration and six channelized streams. We hypothesized that physical habitats and macroinver...

  10. Autonomous Byte Stream Randomizer

    Science.gov (United States)

    Paloulian, George K.; Woo, Simon S.; Chow, Edward T.

    2013-01-01

    Net-centric networking environments are often faced with limited resources and must utilize bandwidth as efficiently as possible. In networking environments that span wide areas, the data transmission has to be efficient without any redundant or exuberant metadata. The Autonomous Byte Stream Randomizer software provides an extra level of security on top of existing data encryption methods. Randomizing the data s byte stream adds an extra layer to existing data protection methods, thus making it harder for an attacker to decrypt protected data. Based on a generated crypto-graphically secure random seed, a random sequence of numbers is used to intelligently and efficiently swap the organization of bytes in data using the unbiased and memory-efficient in-place Fisher-Yates shuffle method. Swapping bytes and reorganizing the crucial structure of the byte data renders the data file unreadable and leaves the data in a deconstructed state. This deconstruction adds an extra level of security requiring the byte stream to be reconstructed with the random seed in order to be readable. Once the data byte stream has been randomized, the software enables the data to be distributed to N nodes in an environment. Each piece of the data in randomized and distributed form is a separate entity unreadable on its own right, but when combined with all N pieces, is able to be reconstructed back to one. Reconstruction requires possession of the key used for randomizing the bytes, leading to the generation of the same cryptographically secure random sequence of numbers used to randomize the data. This software is a cornerstone capability possessing the ability to generate the same cryptographically secure sequence on different machines and time intervals, thus allowing this software to be used more heavily in net-centric environments where data transfer bandwidth is limited.

  11. Streaming gravity mode instability

    International Nuclear Information System (INIS)

    Wang Shui.

    1989-05-01

    In this paper, we study the stability of a current sheet with a sheared flow in a gravitational field which is perpendicular to the magnetic field and plasma flow. This mixing mode caused by a combined role of the sheared flow and gravity is named the streaming gravity mode instability. The conditions of this mode instability are discussed for an ideal four-layer model in the incompressible limit. (author). 5 refs

  12. Dust in the interplanetary medium

    Energy Technology Data Exchange (ETDEWEB)

    Mann, Ingrid; Lamy, Herve [Belgian Institute for Space Aeronomy, Brussels (Belgium); Czechowski, Andrzej [Space Research Center, Polish Academy of Sciences, Warsaw (Poland); Meyer-Vernet, Nicole; Zaslavsky, Arnaud, E-mail: ingrid.mann@aeronomie.b [LESIA, Observatoire de Paris, Meudon (France)

    2010-12-15

    The mass density of dust particles that form from asteroids and comets in the interplanetary medium of the solar system is, near 1 AU, comparable to the mass density of the solar wind. It is mainly contained in particles of micrometer size and larger. Dust and larger objects are destroyed by collisions and sublimation and hence feed heavy ions into the solar wind and the solar corona. Small dust particles are present in large number and as a result of their large charge to mass ratio deflected by electromagnetic forces in the solar wind. For nanodust particles of sizes {approx_equal}1-10 nm, recent calculations show trapping near the Sun and outside from about 0.15 AU ejection with velocities close to solar wind velocity. The fluxes of ejected nanodust are detected near 1 AU with the plasma wave instrument onboard the STEREO spacecraft. Although such electric signals have been observed during dust impacts before, the interpretation depends on several different parameters and data analysis is still in progress.

  13. Dust tori in radio galaxies

    NARCIS (Netherlands)

    van der Wolk, G.; Barthel, P. D.; Peletier, R. F.; Pel, J. W.

    Aims. We investigate the quasar - radio galaxy unification scenario and detect dust tori within radio galaxies of various types. Methods. Using VISIR on the VLT, we acquired sub-arcsecond (similar to 0.40 '') resolution N-band images, at a wavelength of 11.85 mu m, of the nuclei of a sample of 27

  14. Meteors, meteorites and cosmic dust

    International Nuclear Information System (INIS)

    Lebedinets, V.N.

    1987-01-01

    The problem of meteorite origin and meteorite composition is discussed. Nowadays, most scientists suppose that the giant Oort cloud consisting of ice comet nuclei is the sourse of the meteor matter. A principle unity of the matter of meteorites falling to the Earth and cosmic dust is noted as well as that of meteorite bodies evaporating in the atmosphere and bearing meteors and bodies

  15. The global transport of dust

    Science.gov (United States)

    Griffin, Dale W.; Kellogg, C.A.; Garrison, V.H.; Shinn, E.A.

    2002-01-01

    By some estimates as much as two billion metric tons of dust are lifted into the Earth's atmosphere every year. Most of this dust is stirred up by storms, the more dramatic of which are aptly named dust storms. But more than mere dirt is carried aloft. Drifting with the suspended dust particles are soil pollutants such as herbicides and pesticides and a significant number of microorganisms-bacteria, viruses and fungi. We can gain some appreciation of how much microbial life is actually floating in our atmosphere by performing a quick calculation. There are typically about one million bacteria per gram of soil, but let's be conservative and suppose there are only 10,000 bacteria per gram of airborne sediment. Assuming a modest one billion metric tons of sediment in the atmosphere, these numbers translate into a quintillion (1018) sediment-borne bacteria moving around the planet each year-enough to form a microbial bridge between Earth and Jupiter. Here we consider what we've learned about the airborne transport of sediment across the globe, and review some of the remarkable studies in this reemerging field that had it origins more than 100 years ago.

  16. Inorganic chemical composition and chemical reactivity of settled dust generated by the World Trade Center building collapse: Chapter 12

    Science.gov (United States)

    Plumlee, Geoffrey S.; Hageman, Philip L.; Lamothe, Paul J.; Ziegler, Thomas L.; Meeker, Gregory P.; Theodorakos, Peter M.; Brownfield, Isabelle; Adams, Monique G.; Swayze, Gregg A.; Hoefen, Todd M.; Taggart, Joseph E.; Clark, Roger N.; Wilson, S.; Sutley, Stephen J.

    2009-01-01

    Samples of dust deposited around lower Manhattan by the September 11, 2001, World Trade Center (WTC) collapse have inorganic chemical compositions that result in part from the variable chemical contributions of concrete, gypsum wallboard, glass fibers, window glass, and other materials contained in the buildings. The dust deposits were also modified chemically by variable interactions with rain water or water used in street washing and fire fighting. Chemical leach tests using deionized water as the extraction fluid show the dust samples can be quite alkaline, due primarily to reactions with calcium hydroxide in concrete particles. Calcium and sulfate are the most soluble components in the dust, but many other elements are also readily leached, including metals such as Al, Sb, Mo Cr, Cu, and Zn. Indoor dust samples produce leachates with higher pH, alkalinity, and dissolved solids than outdoor dust samples, suggesting most outdoor dust had reacted with water and atmospheric carbon dioxide prior to sample collection. Leach tests using simulated lung fluids as the extracting fluid suggest that the dust might also be quite reactive in fluids lining the respiratory tract, resulting in dissolution of some particles and possible precipitation of new phases such as phosphates, carbonates, and silicates. Results of these chemical characterization studies can be used by health scientists as they continue to track and interpret health effects resulting from the short-term exposure to the initial dust cloud and the longer-term exposure to dusts resuspended during cleanup.

  17. The LHCb Turbo stream

    Energy Technology Data Exchange (ETDEWEB)

    Puig, A., E-mail: albert.puig@cern.ch

    2016-07-11

    The LHCb experiment will record an unprecedented dataset of beauty and charm hadron decays during Run II of the LHC, set to take place between 2015 and 2018. A key computing challenge is to store and process this data, which limits the maximum output rate of the LHCb trigger. So far, LHCb has written out a few kHz of events containing the full raw sub-detector data, which are passed through a full offline event reconstruction before being considered for physics analysis. Charm physics in particular is limited by trigger output rate constraints. A new streaming strategy includes the possibility to perform the physics analysis with candidates reconstructed in the trigger, thus bypassing the offline reconstruction. In the Turbo stream the trigger will write out a compact summary of physics objects containing all information necessary for analyses. This will allow an increased output rate and thus higher average efficiencies and smaller selection biases. This idea will be commissioned and developed during 2015 with a selection of physics analyses. It is anticipated that the turbo stream will be adopted by an increasing number of analyses during the remainder of LHC Run II (2015–2018) and ultimately in Run III (starting in 2020) with the upgraded LHCb detector.

  18. Stream processing health card application.

    Science.gov (United States)

    Polat, Seda; Gündem, Taflan Imre

    2012-10-01

    In this paper, we propose a data stream management system embedded to a smart card for handling and storing user specific summaries of streaming data coming from medical sensor measurements and/or other medical measurements. The data stream management system that we propose for a health card can handle the stream data rates of commonly known medical devices and sensors. It incorporates a type of context awareness feature that acts according to user specific information. The proposed system is cheap and provides security for private data by enhancing the capabilities of smart health cards. The stream data management system is tested on a real smart card using both synthetic and real data.

  19. Streaming Jeans-Alfvén Instability in Quantum Magnetoplasmas

    Science.gov (United States)

    Jamil, M.; Rasheed, A.; Hadi, F.; Ali, G.; Ayub, M.

    2017-10-01

    The physical mechanism of magnetosonic perturbations which modifies the Jeans instability in streaming quantum dusty magnetoplasmas is examined. These perturbations are low frequency and electromagnetic in nature that propagate with Alfvén speed. The fluid model consisting of momentum balance equations for quantum plasmas, Poisson's equation for gravitational potential, and Maxwell's equations for magnetosonic perturbations is used for the coupled solution. The numerical analysis of the dispersion relation elaborates the significant contribution of streaming speed of plasma species at equilibrium v0, uniform external magnetic field B0, electron number density at equilibrium n0e, and variable dust mass md over the Jeans instability. This study helps to understand the possible mechanism responsible for the formation of astrophysical objects.

  20. Chemical Abundances in the Leading Arm of the Magellanic Stream

    Science.gov (United States)

    Fox, Andrew; Barger, Kat; Wakker, Bart; Antwi-Danso, Jacqueline; Richter, Philipp; Casetti, Dana; Howk, Chris; Lehner, Nicolas; D'Onghia, Elena; Crowther, Paul

    2018-01-01

    A vast debris field connects the Milky Way and the Magellanic Clouds. Known as the Leading Arm of the Magellanic Stream, this network of gas clouds represents an active site of gas accretion onto the Milky Way. Previously only one chemical abundance measurement had been made in the Leading Arm, toward the AGN NGC 3783. Here we present new chemical abundance measurements along seven Leading Arm sightlines using Hubble/COS spectra of background AGN. We focus on the O/H and S/H abundances, which have small dust depletion and ionization corrections. These measurements provide important constraints on the origin of the Leading Arm and its relationship to the trailing Stream, and can be used to constrain numerical simulations of Leading Arm formation.