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Sample records for dust analysis laboratory

  1. Laboratory Formation and Analysis of the Materials Comprising Interstellar Dust

    NASA Astrophysics Data System (ADS)

    Scott, Alan Douglas

    The optical properties of interstellar dust analogs are investigated. Thin, solid, amorphous films are deposited on a substrate through excimer laser ablation. This process is analogous to the vapour deposition of atoms and ions which is thought to occur in stellar outflows and the interstellar medium (ISM). Refractive indices are calculated for typical polymeric hydrogenated amorphous carbon (HAC) films. Thickness dependent void structure is shown to influence the resultant density of the substance. Refractive indices are also determined for amorphous magnesium silicates in both the pyroxene (MgSiO3) and olivine (Mg2SiO4) composites. A plausible dust grain model is constructed which successfully reproduces the major features of the diffuse interstellar extinction. The effects of thermal annealing and dehydrogenation of HAC are investigated. The resulting graphitized HAC is shown to exhibit a spectral signature which is commonly associated with gas phase polycyclic aromatic hydrocarbons (PAHs). Thermal emission from HAC is observed for the first time and is shown to be an excellent match to various anomalous unidentified infrared (UIR) emitters. The emission from HAC closely resembles those rare sources labelled Type B UIR emitters in recent works by Geballe (1996) and Tokunaga (1996). Near threshold laser ionization mass spectroscopy (LIMS) of HAC is shown to produce large ionized molecular clusters including fullerenes. The astrophysical implications of these results are discussed.

  2. Laboratory testing and data analysis of the Electrostatic Lunar Dust Analyzer (ELDA) instrument

    NASA Astrophysics Data System (ADS)

    Xie, J.; Sternovsky, Z.; Auer, S.; Drake, K.; Grün, E.; Horanyi, M.; Le, H.; Srama, R.

    2013-12-01

    We report the advance development of the Electrostatic Lunar Dust Analyzer (ELDA) instrument for the detection of individual low-velocity micron-size dust particles mobilized near the lunar surface, and the measurement of the dust charge, velocity vector, and mass. The first article (N. Duncan et al., Planet. Space Sci., 2011) described the measurement principle, optimized instrument geometry, and the initial testing performed on air. The full laboratory prototype of ELDA has now been completed and tested under vacuum. The numerical data analysis is improved to include gravitation and the calculation of the particle's mass. The ELDA operation principle is based on sensing a charged dust particle by an array of wire electrodes as it is passing though the instrument. Each wire electrode is connected to a charge sensitive amplifier and the velocity vector is reconstructed from the signal shapes and amplitudes. Within the instrument, a strong electrostatic field is used to deflect the trajectories of the particles. The dust mass is determined from the change in velocity measured before and after deflection. The instrument is tested using particles with 54μm mean radius and a narrow size distribution. The experimental results and the error analyses show that ELDA can measure the mass of individual particle with a factor of two even for very low signal to noise ratio.

  3. The MECA Payload as a Dust Analysis Laboratory on the MSP 2001 Lander

    NASA Technical Reports Server (NTRS)

    Marshall, J.; Anderson, M.; Buehler, M.; Frant, M.; Fuerstenau, S.; Hecht, M.; Keller, U.; Markiewicz, W.; Meloy, T.; Pike, T.

    1999-01-01

    In a companion abstract, the "Mars Environmental Compatibility Assessment" (MECA) payload for Mars Surveyor Program 2001 (MSP 2001) is described in terms of its capabilities for addressing exobiology on Mars. Here we describe how the same payload elements perform in terms of gathering data about surface dust on the planet. An understanding of the origin and properties of dust is important to both human exploration and planetary geology. The MECA instrument is specifically designed for soil/dust investigations: it is a multifunctional laboratory equipped to assess particulate properties with wet chemistry, camera imagery, optical microscopy (potentially with LTV fluorescence capability), atomic force microscopy (AFM; potentially with mineral-discrimination capabilities), electrometry, active & passive external materials-test panels, mineral hardness testing, and electrostatic & magnetic materials testing. Additionally, evaluation of soil chemical and physical properties as a function of depth down to about 50 cm will be facilitated by the Lander/MECA robot arm on which the camera (RAC) and electrometer are mounted. Types of data being sought for the dust include: (1) general textural and grain-size characterization of the soil as a whole --for example, is the soil essentially dust with other components or is it a clast-supported material in which dust resides only in the clast interstices, (2) size frequency distribution for dust particles in the range 0.01 to 10.00 microns, (3) particle-shape distribution of the soil components and of the fine dust fraction in particular, (4) soil fabric such as grain clustering into clods, aggregates, and cemented/indurated grain amalgamations, as well as related porosity, cohesiveness, and other mechanical soil properties, (5) cohesive relationship that dust has to certain types of rocks and minerals as a clue to which soil materials may be prime hosts for dust "piggybacking", (6) particle, aggregate, and bulk soil electrostatic

  4. Laboratory simulation of dust spectra

    NASA Technical Reports Server (NTRS)

    Allamandola, L. J.; Sandford, S. A.

    1988-01-01

    Laboratory studies of the IR spectra of interstellar dust are reviewed. Studies of the absorption spectra of dense molecular clouds are discussed, including methods to produce interstellar ice analogues, simulations of astronomical spectra, and IR absorption features caused by ices. Comparisons are made between observational and experimental results of interstellar dust studies. Also, the interstellar emission features associated with dusty regions exposed to UV radiation are examined, including bands related to PAHs and PAH-related materials. It is shown that interstellar spectra are more consistant with emission from free PAHs than with emission from particles.

  5. The MECA Payload as a Dust Analysis Laboratory on the MSP 2001 Lander

    NASA Astrophysics Data System (ADS)

    Marshall, J.; Anderson, M.; Buehler, M.; Frant, M.; Fuerstenau, S.; Hecht, M.; Keller, U.; Markiewicz, W.; Meloy, T.; Pike, T.

    1999-09-01

    In a companion abstract, the "Mars Environmental Compatibility Assessment" (MECA) payload for Mars Surveyor Program 2001 (MSP 2001) is described in terms of its capabilities for addressing exobiology on Mars. Here we describe how the same payload elements perform in terms of gathering data about surface dust on the planet. An understanding of the origin and properties of dust is important to both human exploration and planetary geology. The MECA instrument is specifically designed for soil/dust investigations: it is a multifunctional laboratory equipped to assess particulate properties with wet chemistry, camera imagery, optical microscopy (potentially with LTV fluorescence capability), atomic force microscopy (AFM; potentially with mineral-discrimination capabilities), electrometry, active & passive external materials-test panels, mineral hardness testing, and electrostatic & magnetic materials testing. Additionally, evaluation of soil chemical and physical properties as a function of depth down to about 50 cm will be facilitated by the Lander/MECA robot arm on which the camera (RAC) and electrometer are mounted. Types of data being sought for the dust include: (1) general textural and grain-size characterization of the soil as a whole --for example, is the soil essentially dust with other components or is it a clast-supported material in which dust resides only in the clast interstices, (2) size frequency distribution for dust particles in the range 0.01 to 10.00 microns, (3) particle-shape distribution of the soil components and of the fine dust fraction in particular, (4) soil fabric such as grain clustering into clods, aggregates, and cemented/indurated grain amalgamations, as well as related porosity, cohesiveness, and other mechanical soil properties, (5) cohesive relationship that dust has to certain types of rocks and minerals as a clue to which soil materials may be prime hosts for dust "piggybacking", (6) particle, aggregate, and bulk soil electrostatic

  6. The MECA Payload as a Dust Analysis Laboratory on the MSP 2001 Lander

    NASA Technical Reports Server (NTRS)

    Marshall, J.; Anderson, M.; Buehler, M.; Frant, M.; Fuerstenau, S.; Hecht, M.; Keller, U.; Markiewicz, W.; Meloy, T.; Pike, T.

    1999-01-01

    In a companion abstract, the "Mars Environmental Compatibility Assessment" (MECA) payload for Mars Surveyor Program 2001 (MSP 2001) is described in terms of its capabilities for addressing exobiology on Mars. Here we describe how the same payload elements perform in terms of gathering data about surface dust on the planet. An understanding of the origin and properties of dust is important to both human exploration and planetary geology. The MECA instrument is specifically designed for soil/dust investigations: it is a multifunctional laboratory equipped to assess particulate properties with wet chemistry, camera imagery, optical microscopy (potentially with LTV fluorescence capability), atomic force microscopy (AFM; potentially with mineral-discrimination capabilities), electrometry, active & passive external materials-test panels, mineral hardness testing, and electrostatic & magnetic materials testing. Additionally, evaluation of soil chemical and physical properties as a function of depth down to about 50 cm will be facilitated by the Lander/MECA robot arm on which the camera (RAC) and electrometer are mounted. Types of data being sought for the dust include: (1) general textural and grain-size characterization of the soil as a whole --for example, is the soil essentially dust with other components or is it a clast-supported material in which dust resides only in the clast interstices, (2) size frequency distribution for dust particles in the range 0.01 to 10.00 microns, (3) particle-shape distribution of the soil components and of the fine dust fraction in particular, (4) soil fabric such as grain clustering into clods, aggregates, and cemented/indurated grain amalgamations, as well as related porosity, cohesiveness, and other mechanical soil properties, (5) cohesive relationship that dust has to certain types of rocks and minerals as a clue to which soil materials may be prime hosts for dust "piggybacking", (6) particle, aggregate, and bulk soil electrostatic

  7. Laboratory studies of interplanetary dust

    NASA Technical Reports Server (NTRS)

    Walker, R. M.

    1986-01-01

    Interplanetary dust particles (IDPs) are a form of primitive extraterrestrial material. In spite of the formidable experimental problems in working with particles that are too small to be seen with the naked eye, it has proven possible to obtain considerable information concerning their properties and possible origins. Dust particles collected in the stratosphere were reviewed. These particles are the best available samples of interplanetary dust and were studied using a variety of analytical techniques.

  8. Laboratory far-infrared spectroscopy of terrestrial sulphides to support analysis of cosmic dust spectra

    NASA Astrophysics Data System (ADS)

    Brusentsova, T.; Peale, R. E.; Maukonen, D.; Figueiredo, P.; Harlow, G. E.; Ebel, D. S.; Nissinboim, A.; Sherman, K.; Lisse, C. M.

    2012-03-01

    As an aid in interpreting data from space far-infrared (far-IR) missions, such as the Herschel Space Observatory with its Photodetector Array Camera and Spectrometer, this paper presents spectroscopic studies of selected naturally occurring terrestrial sulphide minerals in the wavelength range 15-250 μm. The data can also be used to support the return from other, both past and planned, IR space missions, such as the Infrared Space Observatory, Spitzer, SOFIA, SPiCA and Millimetron. In this study, we present far-IR spectra for 11 natural sulphide minerals in the form of dispersed powders of micron particle dimensions. Samples of various sulphides from the American Museum of Natural History mineral collection were selected based on criteria of diversity and potential astrophysical relevancy, based on their identification in Stardust, in stratospheric interplanetary dust particle samples, or in meteorites. Mineral species include digenite, galena, alabandite, sphalerite, wurtzite, covellite, pyrrhotite, pyrite, marcasite, chalcopyrite and stibnite. Most of the sulphides examined possess prominent and characteristic features in the far-IR range. Spectra obtained are compared to those available from previous studies. Far-IR peak frequencies and mass absorption coefficient values are tabulated. Effects of particle size distribution, low temperature, and provenance on IR spectra are demonstrated for selected samples.

  9. Laboratory Far-infrared Spectroscopy Of Terrestrial Phyllosilicates To Support Analysis Of Cosmic Dust Spectra.

    NASA Astrophysics Data System (ADS)

    Yesiltas, Mehmet; Brusentsova, T.; Peale, R.; Maukonen, D.; Figueiredo, P.; Harlow, G. H.; Ebel, D. S.; Nissinboim, A.; Sherman, K.; Lisse, C. M.

    2012-01-01

    Poster Abstract: 219th AAS Meeting M. Yesiltas1, T. Brusentsova1, R. E. Peale1, D. Maukonen1, P. Figueiredo1, G. E. Harlow2, D. S. Ebel2, A. Nissinboim2, K. Sherman2, and C. M. Lisse3 Remote spectral detection of hydrated minerals is of general interest in the solar system and dusty circumstellar disks. This paper presents spectroscopy of terrestrial phyllosilicate minerals in the wavelength range 15 - 250 µm to support interpretation of returned data from far-IR space-missions such as the Herschel Space Observatory. The far-IR spectral region beyond 15 micron wavelength is especially diagnostic of mineral composition and crystal structure. Relatively little far-IR spectral data exists in the literature on suitably-characterized naturally-occurring phyllosilicate minerals in the wavelength range 60-210 microns corresponding to the PACS instrument of Herschel Space Observatory. Extending the database of laboratory far-IR spectra of terrestrial mineral analogs is therefore desirable and timely. Seventeen phyllosilicate minerals expected in various astronomical environments were sampled from the American Museum of Natural History for diversity and astrophysical relevancy, based on their identification in Stardust, in stratospheric IDP samples, or in meteorites. These include serpentines (Antigorite and Chrysotile), smectites (Talc, Pyrophyllite, Vermiculite, Montmorillonite, Beidellite, Saponite, Nontronite and Hectorite), chlorites (Clinochlore), micas (Muscovite, Paragonite, Margarite, Clintonite, Biotite and Illite), and kaolinites (Dickite, Nacrite, Kaolinite, Halloysite, Attapulgite and Sepiolite). Spectra of micron-sized powder suspensions in polyethelyne pellets reveal prominent and characteristic far-IR features, which differ significantly in some cases from already published spectra, where available. Acknowledgements : This research was supported by NASA-JPL Contract # 1327221. 1Department of Physics, University of Central Florida, Orlando FL 32816 USA2

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

    PubMed

    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.

  11. Imaging Charged Dust in Laboratory Plasmas

    NASA Astrophysics Data System (ADS)

    Goree, John

    2010-05-01

    Laboratory experiments with dust grains are described in this talk, which will include numerous images and videos from the experiments. In all the experiments, grains are immersed in plasma, and they are electrically charged. In the first experiment, grains are synthesized under conditions that simulate the outflow of carbon stars. These grains are grown in the gas phase with a carbon vapor. They grow by homogeneous nucleation, accretion, and coagulation. After growth, they are collected and imaged by scanning electron microscopy. These images reveal the grain morphology. In the second experiment, the structure and dynamics of the liquid or solid-phase centers of a star is simulated in the laboratory using charged grains (precision micron-size spheres) as proxies for protons. These grains are imaged by video microscopy, revealing how they self-organize, arranging themselves spatially in a crystalline-like lattice due to mutual Coulomb repulsion. Video microscopy allows tracking the motion of the microspheres and calculating their velocities. This measurement allows the experimenter to detect waves corresponding to random thermal motion, and from the properties of these waves one can measure the grain's charge. In the third experiment, sound waves in a cloud of charged dust are observed using high-speed video cameras. The compression and rarefaction of the dust-grain number density are easily observed in the video. Work supported by NSF and NASA.

  12. Laboratory observations of self-excited dust acoustic shock waves

    NASA Astrophysics Data System (ADS)

    Merlino, Robert L.; Heinrich, Jonathon R.; Kim, Su-Hyun

    2009-11-01

    Dust acoustic waves have been discussed in connection with dust density structures in Saturn's rings and the Earth's mesosphere, and as a possible mechanism for triggering condensation of small grains in dust molecular clouds. Dust acoustic waves are a ubiquitous occurrence in laboratory dusty plasmas formed in glow discharges. We report observations of repeated, self-excited dust acoustic shock waves in a dc glow discharge dusty plasma using high-speed video imaging. Two major observations will be presented: (1) The self-steepening of a nonlinear dust acoustic wave into a saw-tooth wave with sharp gradient in dust density, very similar to those found in numerical solutions [1] of the fully nonlinear fluid equations for nondispersive dust acoustic waves, and (2) the collision and confluence of two dust acoustic shock waves. [4pt] [1] B. Eliasson and P. K. Shukla, Phys. Rev. E 69, 067401 (2004).

  13. Field Research and Laboratory Sample Analysis of Dust-Water-Organics-Life from Mars Analogue Extreme Environments

    NASA Astrophysics Data System (ADS)

    Foing, Bernard H.; Ehrenfreund, Pascale; ILEWG EuroMoonMars Team

    2015-08-01

    We describe results from the data analysis from a series of field research campaigns (ILEWG EuroMoonMars campaigns 2009* to 2013) in the extreme environment of the Utah desert relevant to habitability and astrobiology in Mars environments, and in order to help in the interpretation of Mars missions measurements from orbit (MEX, MRO) or from the surface (MER, MSL). We discuss results relevant to the scientific study of the habitability factors influenced by the properties of dust, organics, water history and the diagnostics and characterisation of microbial life. We also discuss perspectives for the preparation of future lander and sample return missions. We deployed at Mars Desert Research station, Utah, a suite of instruments and techniques including sample collection, context imaging from remote to local and microscale, drilling, spectrometers and life sensors. We analyzed how geological and geochemical evolution a ected local parameters (mineralogy, organics content, environment variations) and the habitability and signature of organics and biota. We find high diversity in the composition of soil samples even when collected in close proximity, the low abundances of detectable PAHs and amino acids and the presence of biota of all three domains of life with signi cant heterogeneity. An extraordinary variety of putative extremophiles was observed. A dominant factor seems to be soil porosity and lower clay-sized particle content. A protocol was developed for sterile sampling, contamination issues, and the diagnostics of biodiversity via PCR and DGGE analysis in soils and rocks samples. We compare 2009 campaign results to new measurements from 2010-2013 campaigns: comparison between remote sensing and in-situ measurements; the study of minerals; the detection of organics and signs of life.References * in Foing, Stoker Ehrenfreund (Editors, 2011) Astrobiology field Research in Moon/Mars Analogue Environments", Special Issue of International Journal of Astrobiology

  14. Simulating STARDUST: Reproducing Impacts of Interstellar Dust in the Laboratory

    NASA Astrophysics Data System (ADS)

    Postberg, F.; Srama, R.; Hillier, J. K.; Sestak, S.; Green, S. F.; Trieloff, M.; Grün, E.

    2008-09-01

    Our experiments are carried out to support the analysis of interstellar dust grains, ISDGs, brought to earth by the STARDUST mission. Since the very first investigations, it has turned out that the major problem of STARDUST particle analysis is the modification (partly even the destruction) during capture when particles impact the spacecraft collectors with a velocity of up to 20 km/s. While it is possible to identify, extract, and analyse cometary grains larger than a few microns in aerogel and on metal collector plates, the STARDUST team is not yet ready for the identification, extraction, and analysis of sub-micron sized ISDGs with impact speeds of up to 20 km/s. Reconstructing the original particle properties requires a simulation of this impact capture process. Moreover, due to the lack of laboratory studies of high speed impacts of micron scale dust into interstellar STARDUST flight spares, the selection of criteria for the identification of track candidates is entirely subjective. Simulation of such impact processes is attempted with funds of the FRONTIER program within the framework of the Heidelberg University initiative of excellence. The dust accelerator at the MPI Kernphysik is a facility unique in the world to perform such experiments. A critical point is the production of cometary and interstellar dust analogue material and its acceleration to very high speeds of 20 km/s, which has never before been performed in laboratory experiments. Up to now only conductive material was successfully accelerated by the 2 MV Van de Graaf generator of the dust accelerator facility. Typical projectile materials are Iron, Aluminium, Carbon, Copper, Silver, and the conducting hydrocarbon Latex. Ongoing research now enables the acceleration of any kind of rocky planetary and interstellar dust analogues (Hillier et al. 2008, in prep.). The first batch of dust samples produced with the new method consists of micron and submicron SiO2 grains. Those were successfully

  15. Laboratory Micrometeroid/Dust Ablation Studies

    NASA Astrophysics Data System (ADS)

    Thomas, E.; Horanyi, M.; Janches, D.; Munsat, T. L.; Plane, J. M. C.; Simolka, J.; Sternovsky, Z.

    2014-12-01

    Each day, somewhere between 5-270 tonnes of meteoric material ablates in Earth's upper atmosphere. Thisenormous range is significant because the Interplanetary Dust Particle (IDP) input has implications in ourunderstanding of meteor transport in the atmosphere, the formation of layers of metal atoms and ions,nucleation of noctilucent clouds, effects on stratospheric aerosols and O3 chemistry, and dust evolution inour solar system. As the dust ablates, it produces light, as well as a plasma trail of ionized atmosphericatoms and electrons. These meteor signatures are detected by photographic means, or by radar, but thereremain uncertainties in the luminous efficiency and ionization coefficient of meteors - two parameters thatare essential to evaluate densities, masses, height distributions and fluxes. Precise measurements of theseparameters would allow for not only an understanding of the layers of metal atoms and ions and meteoricsmoke particles in the mesosphere and lower thermosphere, but also would allow for the Earth's atmosphereto be used as a dust detector to detect and characterize the dust environment in our solar system. This work discusses the preliminary results of the new dust ablation facility at the 3 MV hypervelocity dust accelerator at the Institute for Modeling Plasma, Atmospheres and Cosmic Dust (IMPACT) at the University of Colorado, which aims to characterize the ionization coefficient and luminous efficiency of ablating micrometeroids.

  16. Laboratory Investigation of Space and Planetary Dust Grains

    NASA Technical Reports Server (NTRS)

    Spann, James

    2005-01-01

    Dust in space is ubiquitous and impacts diverse observed phenomena in various ways. Understanding the dominant mechanisms that control dust grain properties and its impact on surrounding environments is basic to improving our understanding observed processes at work in space. There is a substantial body of work on the theory and modeling of dust in space and dusty plasmas. To substantiate and validate theory and models, laboratory investigations and space borne observations have been conducted. Laboratory investigations are largely confined to an assembly of dust grains immersed in a plasma environment. Frequently the behaviors of these complex dusty plasmas in the laboratory have raised more questions than verified theories. Space borne observations have helped us characterize planetary environments. The complex behavior of dust grains in space indicates the need to understand the microphysics of individual grains immersed in a plasma or space environment.

  17. Sampling and analysis method for measuring airborne coal dust mass in mixtures with limestone (rock) dust

    PubMed Central

    Barone, T. L.; Patts, J. R.; Janisko, S. J.; Colinet, J. F.; Patts, L. D.; Beck, T. W.; Mischler, S. E.

    2016-01-01

    Airborne coal dust mass measurements in underground bituminous coal mines can be challenged by the presence of airborne limestone dust, which is an incombustible dust applied to prevent the propagation of dust explosions. To accurately measure the coal portion of this mixed airborne dust, the National Institute for Occupational Safety and Health (NIOSH) developed a sampling and analysis protocol that used a stainless steel cassette adapted with an isokinetic inlet and the low temperature ashing (LTA) analytical method. The Mine Safety and Health Administration (MSHA) routinely utilizes this LTA method to quantify the incombustible content of bulk dust samples collected from the roof, floor, and ribs of mining entries. The use of the stainless steel cassette with isokinetic inlet allowed NIOSH to adopt the LTA method for the analysis of airborne dust samples. Mixtures of known coal and limestone dust masses were prepared in the laboratory, loaded into the stainless steel cassettes, and analyzed to assess the accuracy of this method. Coal dust mass measurements differed from predicted values by an average of 0.5%, 0.2%, and 0.1% for samples containing 20%, 91%, and 95% limestone dust, respectively. The ability of this method to accurately quantify the laboratory samples confirmed the validity of this method and allowed NIOSH to successfully measure the coal fraction of airborne dust samples collected in an underground coal mine. PMID:26618374

  18. Sampling and analysis method for measuring airborne coal dust mass in mixtures with limestone (rock) dust.

    PubMed

    Barone, T L; Patts, J R; Janisko, S J; Colinet, J F; Patts, L D; Beck, T W; Mischler, S E

    2016-01-01

    Airborne coal dust mass measurements in underground bituminous coal mines can be challenged by the presence of airborne limestone dust, which is an incombustible dust applied to prevent the propagation of dust explosions. To accurately measure the coal portion of this mixed airborne dust, the National Institute for Occupational Safety and Health (NIOSH) developed a sampling and analysis protocol that used a stainless steel cassette adapted with an isokinetic inlet and the low temperature ashing (LTA) analytical method. The Mine Safety and Health Administration (MSHA) routinely utilizes this LTA method to quantify the incombustible content of bulk dust samples collected from the roof, floor, and ribs of mining entries. The use of the stainless steel cassette with isokinetic inlet allowed NIOSH to adopt the LTA method for the analysis of airborne dust samples. Mixtures of known coal and limestone dust masses were prepared in the laboratory, loaded into the stainless steel cassettes, and analyzed to assess the accuracy of this method. Coal dust mass measurements differed from predicted values by an average of 0.5%, 0.2%, and 0.1% for samples containing 20%, 91%, and 95% limestone dust, respectively. The ability of this method to accurately quantify the laboratory samples confirmed the validity of this method and allowed NIOSH to successfully measure the coal fraction of airborne dust samples collected in an underground coal mine.

  19. Laboratory dust experiments - Tracing the composition of cometary dust

    NASA Technical Reports Server (NTRS)

    Greenberg, J. M.

    1983-01-01

    The structure and composition of the comet nucleus are investigated theoretically on the basis of aggregation models and laboratory simulations of interstellar-grain evolution. The results are presented in graphs, diagrams, and drawings and discussed in detail. The nucleus is described as a loose tangle of rodlike grains containing about 28 percent H2O, 10 percent CO2 and CO, and 33 percent nonvolatile submicron-size grit particles (silicates, complex organics, and carbon). Evidence from meteorites suggests that the C-12/C-13 ratio of the volatile components is greater than 100.

  20. Laboratory evaluation of the CIP 10 personal dust sampler.

    PubMed

    Gero, A; Tomb, T

    1988-06-01

    The "capteur individuel de poussiere" CIP 10 personal dust sampler--developed by the Centre d'Etudes et Recherches de Charbonnages de France (CERCHAR) research organization--is a small, quiet, lightweight unit which samples at a flow rate of 10 L/min. It is a three-stage sampler, using two stages to remove nonrespirable dust particles and one stage to collect the respirable fraction. Airflow through the sampler is induced by the third stage, which is a rotating collector cup that contains a fine grade sponge. Laboratory tests were conducted in a dust chamber using aerosols of Arizona road dust, coal dust and silica dust. Aerosol concentrations measured with the CIP 10 were compared to those measured with the coal mine dust personal sampler unit used in the United States. The results of this study showed that aerosol concentrations measured with the CIP 10 were linearly related to those obtained with the coal mine dust personal sampler. The relationship, however, was dependent on preselector configuration and aerosol characteristics. The collection medium allows some small particles (less than 3 microns) to pass through the sampler without being collected. As much as 13% (by weight) of the aerosol that penetrated through the preseparating stages was exhausted from the sampler.

  1. A New Laboratory For Terahertz Characterization Of Cosmic Analog Dusts

    NASA Astrophysics Data System (ADS)

    Perera, Thushara; Liu, Lunjun; Breyer, Fiona; Schonert, Ryan; O'Shea, Kyle; Roesner, Rebecca

    2016-06-01

    Most studies conducted with observatories such as ALMA, SOFIA, PLANCK, and Herschel will benefit from knowledge of (1) the predominant cosmic dust species in various environments and (2) the mm/sub-mm optical properties of cosmic dusts, including the temperature dependent-emissivity and spectral index. We have undertaken two efforts to enable the laboratory study of cosmic analogs dusts in the frequency range 60-2000 GHz. They are: (1) the construction of a novel compact Fourier Transform Spectrometer (FTS) design coupled to a dry 4-K cryostat which houses a cooled sample exchanger (filter wheel) and a bolometer. (2) The production of Mg- and Fe-rich silicate dusts using sol-gel methods; various tests to determine their physical and chemical properties; embedding of samples in LDPE pellets for insertion into the novel FTS. This presentation will focus on the current status of the apparatus and data from its first few months of use.

  2. Dust devil sediment flux on Earth and Mars: Laboratory simulations

    NASA Astrophysics Data System (ADS)

    Neakrase, Lynn D. V.; Greeley, Ronald

    2010-03-01

    Laboratory simulations using the Arizona State University Vortex Generator (ASUVG) were run to simulate sediment flux in dust devils in terrestrial ambient and Mars-analog conditions. The objective of this study was to measure vortex sediment flux in the laboratory to yield estimations of natural dust devils on Earth and Mars, where all parameters may not be measured. These tests used particles ranging from 2 to 2000 μm in diameter and 1300 to 4800 kg m -3 in density, and the results were compared with data from natural dust devils on Earth and Mars. Typically, the cores of dust devils (regardless of planetary environment) have a pressure decrease of ˜0.1-1.5% of ambient atmospheric pressure, which enhances the lifting of particles from the surface. Core pressure decreases in our experiments ranged from ˜0.01% to 5.00% of ambient pressure (10 mbar Mars cases and 1000 mbar for Earth cases) corresponding to a few tenths of a millibar for Mars cases and a few millibars for Earth cases. Sediment flux experiments were run at vortex tangential wind velocities of 1-45 m s -1, which typically correspond to ˜30-70% above vortex threshold values for the test particle sizes and densities. Sediment flux was determined by time-averaged measurements of mass loss for a given vortex size. Sediment fluxes of ˜10 -6-10 0 kg m -2 s -1 were obtained, similar to estimates and measurements for fluxes in dust devils on Earth and Mars. Sediment flux is closely related to the vortex intensity, which depends on the strength of the pressure decrease in the core (Δ P). This study found vortex size is less important for lifting materials because many different diameters can have the same Δ P. This finding is critical in scaling the laboratory results to natural dust devils that can be several orders of magnitude larger than the laboratory counterparts.

  3. ANALYSIS OF DUST DELIQUESCENCE FOR FEP SCREENING

    SciTech Connect

    C. Bryan

    2005-08-26

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

  4. Atmospheric aging of dust ice nucleating particles - a combined laboratory and field approach

    NASA Astrophysics Data System (ADS)

    Boose, Yvonne; Rodríguez, Sergio; García, M. Isabel; Linke, Claudia; Schnaiter, Martin; Zipori, Assaf; Crawford, Ian; Lohmann, Ulrike; Kanji, Zamin A.; Sierau, Berko

    2016-04-01

    We present INP data measured in-situ at two mostly free tropospheric locations: the High Altitude Research Station Jungfraujoch (JFJ) in the Swiss Alps, located at 3580 m above sea level (asl) and the Izaña observatory on Tenerife, off the West African shore (2373 m asl). INP concentrations were measured online with the Portable Ice Nucleation Chamber, PINC, at the Jungfraujoch in the winters of 2012, 2013 and 2014 and at Izaña in the summers of 2013 and 2014. Each measurement period lasted between 2 to 6 weeks. During summer, Izaña is frequently within the Saharan Air Layer and thus often exposed to Saharan dust events. Saharan dust also reaches the Jungfraujoch mainly during spring. For offline ice nucleation analysis in the laboratory under similar thermodynamic conditions, airborne dust was collected a) at Izaña with a cyclone directly from the air and b) collected from the surface of the Aletsch glacier close to the JFJ after deposition. Supporting measurements of aerosol particle size distributions and fluorescence were conducted at both locations, as well as cloud water isotope analysis at the Jungfraujoch and aerosol chemistry at Izaña. For both locations the origin of the INPs was investigated with a focus on dust and biological particles using back trajectories and chemical signature. Results show that dust aerosol is the dominant INP type at both locations at a temperature of 241 K. In addition to Saharan dust, also more local, basaltic dust is found at the Jungfraujoch. Biological particles are not observed to play a role for ice nucleation in clouds during winter at Jungfraujoch but are enriched in INP compared to the total aerosol at Izaña also during dust events. The comparison of the laboratory and the field measurements at Izaña indicates a good reproducibility of the field data by the collected dust samples. Field and laboratory data of the dust samples from both locations show that the dust arriving at JFJ is less ice nucleation active

  5. a New Laboratory for Terahertz Characterization of Cosmic Analog Dusts

    NASA Astrophysics Data System (ADS)

    Perera, Thushara

    2016-06-01

    Two efforts have been underway to enable the laboratory study of cosmic analogs dusts in the frequency range 60--2000 GHz. They are: (1) the construction of a novel compact Fourier Transform Spectrometer (FTS) design coupled to a dry 4-K cryostat which houses a cooled sample exchanger (filter wheel) and a bolometer. (2) The production of Mg- and Fe-rich silicate dusts using sol-gel methods; various tests to determine their physical and chemical properties; embedding of samples in LDPE pellets for insertion into the novel FTS. This presentation will focus on the current status of the apparatus and data from its first few months of use.

  6. Laboratory Studies of Simple Dust Analogs in Astrophysical Environments

    NASA Astrophysics Data System (ADS)

    Brucato, John R.; Nuth, Joseph A., III

    2010-02-01

    Laboratory techniques seek to understand and to place limits upon chemical and physical processes that occur in space. Dust can be modified by long-term exposure to high-energy cosmic rays, thus rendering crystalline material amorphous.It can be heated to high temperatures, thus making amorphous material crystalline. Dust may be coated by organic molecules, changing its spectral properties, or may act as a catalyst in the synthesis of both simple and complex molecules. We describe experimental studies to understand such processes and report studies that focus on the properties of simple oxide grains. We give an overview of the synthesis and characterization techniques most often utilized to study the properties of solids in the laboratory and have concentrated on those techniques that have been most useful for the interpretation of astrophysical data. We also discuss silicate catalysis as an important mechanism that may drive the formation of complex molecular compounds relevant for prebiotic chemistry.

  7. Laboratory investigation of antenna signals from dust impacts on spacecraft

    NASA Astrophysics Data System (ADS)

    Sternovsky, Zoltan; Collette, Andrew; Malaspina, David M.; Thayer, Frederick

    2016-04-01

    Electric field and plasma wave instruments act as dust detectors picking up voltage pulses induced by impacts of particulates on the spacecraft body. These signals enable the characterization of cosmic dust environments even with missions without dedicated dust instruments. For example, the Voyager 1 and 2 spacecraft performed the first detection of dust particles near Uranus, Neptune, and in the outer solar system [Gurnett et al., 1987, 1991, 1997]. The two STEREO spacecraft observed distinct signals at high rate that were interpreted as nano-sized particles originating from near the Sun and accelerated to high velocities by the solar wind [MeyerVernet et al, 2009a, Zaslavsky et al., 2012]. The MAVEN spacecraft is using the antennas onboard to characterize the dust environment of Mars [Andersson et al., 2014] and Solar Probe Plus will do the same in the inner heliosphere. The challenge, however, is the correct interpretation of the impact signals and calculating the mass of the dust particles. The uncertainties result from the incomplete understanding of the signal pickup mechanisms, and the variation of the signal amplitude with impact location, the ambient plasma environment, and impact speed. A comprehensive laboratory study of impact generated antenna signals has been performed recently using the IMPACT dust accelerator facility operated at the University of Colorado. Dust particles of micron and submicron sizes with velocities of tens of km/s are generated using a 3 MV electrostatic analyzer. A scaled down model spacecraft is exposed to the dust impacts and one or more antennas, connected to sensitive electronics, are used to detect the impact signals. The measurements showed that there are three clearly distinct signal pickup mechanisms due to spacecraft charging, antenna charging and antenna pickup sensing space charge from the expanding plasma cloud. All mechanisms vary with the spacecraft and antenna bias voltages and, furthermore, the latter two

  8. Effect of soil texture and chemical properties on laboratory-generated dust emissions from SW North America

    NASA Astrophysics Data System (ADS)

    Mockford, T.; Zobeck, T. M.; Lee, J. A.; Gill, T. E.; Dominguez, M. A.; Peinado, P.

    2012-12-01

    Understanding the controls of mineral dust emissions and their particle size distributions during wind-erosion events is critical as dust particles play a significant impact in shaping the earth's climate. It has been suggested that emission rates and particle size distributions are independent of soil chemistry and soil texture. In this study, 45 samples of wind-erodible surface soils from the Southern High Plains and Chihuahuan Desert regions of Texas, New Mexico, Colorado and Chihuahua were analyzed by the Lubbock Dust Generation, Analysis and Sampling System (LDGASS) and a Beckman-Coulter particle multisizer. The LDGASS created dust emissions in a controlled laboratory setting using a rotating arm which allows particle collisions. The emitted dust was transferred to a chamber where particulate matter concentration was recorded using a DataRam and MiniVol filter and dust particle size distribution was recorded using a GRIMM particle analyzer. Particle size analysis was also determined from samples deposited on the Mini-Vol filters using a Beckman-Coulter particle multisizer. Soil textures of source samples ranged from sands and sandy loams to clays and silts. Initial results suggest that total dust emissions increased with increasing soil clay and silt content and decreased with increasing sand content. Particle size distribution analysis showed a similar relationship; soils with high silt content produced the widest range of dust particle sizes and the smallest dust particles. Sand grains seem to produce the largest dust particles. Chemical control of dust emissions by calcium carbonate content will also be discussed.

  9. In-Situ Dust Detection by Spacecraft Antennas: Laboratory Characterization of Particle Energies and Geometrical Effects

    NASA Astrophysics Data System (ADS)

    Rocha, J. R. R.; Collette, A.; Sternovsky, Z.; Malaspina, D.; Thayer, F.

    2015-12-01

    We describe direct laboratory investigation of signals generated by hypervelocity dust impacts on spacecraft. Although the majority of spacecraft do not carry dedicated dust detectors, those with antenna-based instruments routinely observe impulsive signals from dust impacts on the spacecraft and antennas. Recent analysis of signals from the STEREO spacecraft WAVES electric field sensors, and unexpected high-altitude observations at Mars by MAVEN's LPW instrument, highlight the opportunity for in-situ dust detection by such spacecraft. However, quantitative interpretation of the spacecraft data currently suffers from large uncertainties, including the quantity and energy distribution of charged particles released, the effect of the spacecraft configuration and impact location, and the near-spacecraft electric fields and plasma environment. We report a series of experiments conducted at the IMPACT hypervelocity dust accelerator facility at the University of Colorado Boulder, to investigate (1) the effects of spacecraft and antenna potential on charge recollection and consequent signals, (2) the energy distribution of charged particles produced by dust impacts on realistic spacecraft materials at various speeds, and (3) the influence of spacecraft geometry, using impacts distributed across a high-fidelity model of the STEREO spacecraft. Implications for future spacecraft observations are also discussed.

  10. Cometary Dust Characteristics: Comparison of Stardust Craters with Laboratory Impacts

    NASA Technical Reports Server (NTRS)

    Kearsley, A. T.; Burchell, M. J.; Graham, G. A.; Horz, F.; Wozniakiewicz, P. A.; Cole, M. J.

    2007-01-01

    Aluminium foils exposed to impact during the passage of the Stardust spacecraft through the coma of comet Wild 2 have preserved a record of a wide range of dust particle sizes. The encounter velocity and dust incidence direction are well constrained and can be simulated by laboratory shots. A crater size calibration programme based upon buckshot firings of tightly constrained sizes (monodispersive) of glass, polymer and metal beads has yielded a suite of scaling factors for interpretation of the original impacting grain dimensions. We have now extended our study to include recognition of particle density for better matching of crater to impactor diameter. A novel application of stereometric crater shape measurement, using paired scanning electron microscope (SEM) images has shown that impactors of differing density yield different crater depth/diameter ratios. Comparison of the three-dimensional gross morphology of our experimental craters with those from Stardust reveals that most of the larger Stardust impacts were produced by grains of low internal porosity.

  11. Lunar Dust Analysis Package - LDAP

    NASA Astrophysics Data System (ADS)

    Chalkley, S. A.; Richter, L.; Goepel, M.; Sovago, M.; Pike, W. T.; Yang, S.; Rodenburg, J.; Claus, D.

    2012-09-01

    The Lunar Dust Analysis package (L-DAP) is a suite of payloads which have been designed to operate in synergy with each other at the Lunar Surface. The benefits of combining these payloads in a single package allow very precise measurements of a particular regolith sample. At the same time the integration allows mass savings since common resources are shared and this also means that interfaces with the Lander are simplified significantly leading to benefits of integration and development of the overall mission. Lunar Dust represents a real hazard for lunar exploration due to its invasive, fine microscopic structure and toxic properties. However it is also valuable resource which could be exploited for future exploration if the characteristics and chemical composition is well known. Scientifically, the regolith provides an insight into the moon formation process and there are areas on the Moon which have never been ex-plored before. For example the Lunar South Pole Aitken Basin is the oldest and largest on the moon, providing excavated deep crust which has not been found on the previous lunar landing missions. The SEA-led team has been designing a compact package, known as LDAP, which will provide key data on the lunar dust properties. The intention is for this package to be part of the payload suite deployed on the ESA Lunar Lander Mission in 2018. The LDAP has a centralised power and data electronics, including front end electronics for the detectors as well as sample handling subsystem for the following set of internal instruments : • Optical Microscope - with a 1μm resolution to provide context of the regolith samples • Raman and LIBS spectrographic instrumentation providing quantification of mineral and elemental composition information of the soil at close to grain scale. This includes the capability to detect (and measure abundance of) crystalline and adsorbed volatile phases, from their Raman signature. The LIBS equipment will also allow chemical

  12. Laboratory study of carbonaceous dust and molecules of astrochemical interest

    NASA Astrophysics Data System (ADS)

    Cataldo, F.; Garcia-Hernandez, D. A.; Manchado, A.; Kwok, S.

    2016-07-01

    In this paper are reviewed some research works dedicated to the study of carbonaceous dust and molecules of astrochemical interest. First of all it is discussed the carbon arc through which it is possible to produce carbon soot and fullerenes under helium but also many other different products just changing the arcing conditions. For example, when the carbon arc is struck in an hydrocarbon solvent it is possible to produce and trap polyynes in the solvent. Monocyanopolyynes and dicyanopolyynes can be produced as well by selecting the appropriate conditions. Amorphous carbon soot or partially graphitized carbon black can be produced with the carbon arc. Fullerenes were found in space thanks to the reference infrared spectra and the absorption cross sections which were determined in laboratory. Fullerenes are readily reactive with hydrogen yielding fulleranes the hydrogenated fullerenes. Furthermore fullerenes react with PAHs and with iron carbonyl yielding adducts. All these fullerene derivatives were synthesized and their reference spectra recorded in laboratory. It was proposed that petroleum fractions can be used as model substrates in the explanation of the carriers of the AIB (Aromatic Infrared Bands) observed in protoplanetary and planetary nebulae and the UIE (Unidentified Infrared Bands) found in the interstellar medium.

  13. Dust trajectory sensor: accuracy and data analysis.

    PubMed

    Xie, J; Sternovsky, Z; Grün, E; Auer, S; Duncan, N; Drake, K; Le, H; Horanyi, M; Srama, R

    2011-10-01

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

  14. Dust trajectory sensor: Accuracy and data analysis

    SciTech Connect

    Xie, J.; Horanyi, M.; Sternovsky, Z.; Gruen, E.; Duncan, N.; Drake, K.; Le, H.; Auer, S.; Srama, R.

    2011-10-15

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

  15. NETL - Thermogravimetric Analysis Laboratory

    SciTech Connect

    Richards, George

    2013-06-12

    Researchers in NETL's Thermal Analysis Laboratory are investigating chemical looping combustion. As a clean and efficient fossil fuel technology, chemical looping combustion controls CO2 emissions and offers a promising alternative to traditional combustion.

  16. NETL - Thermogravimetric Analysis Laboratory

    ScienceCinema

    Richards, George

    2016-07-12

    Researchers in NETL's Thermal Analysis Laboratory are investigating chemical looping combustion. As a clean and efficient fossil fuel technology, chemical looping combustion controls CO2 emissions and offers a promising alternative to traditional combustion.

  17. Hypervelocity Dust Impacts in Space and the Laboratory

    NASA Astrophysics Data System (ADS)

    Horanyi, Mihaly; Colorado CenterLunar Dust; Atmospheric Studies (CCLDAS) Team

    2013-10-01

    Interplanetary dust particles continually bombard all objects in the solar system, leading to the excavation of material from the target surfaces, the production of secondary ejecta particles, plasma, neutral gas, and electromagnetic radiation. These processes are of interest to basic plasma science, planetary and space physics, and engineering to protect humans and instruments against impact damages. The Colorado Center for Lunar Dust and Atmospheric Studies (CCLDAS) has recently completed a 3 MV dust accelerator, and this talk will summarize our initial science results. The 3 MV Pelletron contains a dust source, feeding positively charged micron and sub-micron sized particles into the accelerator. We will present the technical details of the facility and its capabilities, as well as the results of our initial experiments for damage assessment of optical devices, and penetration studies of thin films. We will also report on the completion of our dust impact detector, the Lunar Dust Experiment (LDEX), is expected to be flying onboard the Lunar Atmosphere and Dust Environment Explorer (LADEE) mission by the time of this presentation. LDEX was tested, and calibrated at our dust accelerator. We will close by offering the opportunity to use this facility by the planetary, space and plasma physics communities.

  18. A laboratory study of sediment flux within dust devils on Earth and Mars

    NASA Astrophysics Data System (ADS)

    Neakrase, Lynn D. V.

    Laboratory experiments using the Arizona State University Vortex Generator (ASUVG) were run to estimate sediment flux in dust devils on Earth and Mars. Particles of different sizes and densities were utilized in dust devil simulations at Earth and Mars atmospheric conditions to determine trends in sediment flux by measuring the mass loss as a function of time and size of the vortex. Characterization of the effects of non-erodible roughness elements on vortex flow, particle threshold, and sediment flux was also conducted. Laboratory sediment fluxes were used with in situ lander data and orbiter image statistics on dust devil distributions to estimate average sediment fluxes from five sites on Mars. Sediment flux results showed that dust particles (less than 62 microns) are more easily lofted in dust devils than sand particles (62-2000 microns). Laboratory sediment fluxes ranged from 1E-6 to 1E0 kilograms per square meter per second when no roughness elements were present. Roughness elements resulted in lowered efficiency of the vortices leading to increased particle thresholds and decreased sediment fluxes for experiments involving medium- and high- density roughness arrays. However flow was enhanced for low-density roughness arrays (small elements) allowing lower thresholds and increased sediment fluxes led to the concept of an "optimal roughness" for dust devil sediment lifting. Laboratory results of dust devil sediment fluxes were used to estimate sediment fluxes from landing sites and sites with orbital images of dust devils. Laboratory sediment flux estimates yielded a range of 0.5 to 45.0 kilograms per square kilometer per sol depending on sediment availability, dust devil activity, surface roughness, and gravity differences between Earth and Mars. The results suggested that dust devil sediment flux input to the martian dust cycle could vary from region to region.

  19. Laboratory Measurements of Optical and Physical Properties of Individual Lunar Dust Grains

    NASA Astrophysics Data System (ADS)

    Abbas, M.; Tankosic, D.; Craven, P.; Hoover, R.; Taylor, L.; Spann, J.; Leclair, A.; West, E.

    The lunar surface is covered with a thick layer of sub-micron micron size dust grains formed by meteoritic impact over billions of years The fine dust grains are levitated and transported on the lunar surface and transient dust clouds over the lunar horizon were observed by experiments during the Apollo 17 mission Theoretical models suggest that the dust grains on the lunar surface are charged by the solar UV radiation as well as the solar wind Even without any physical activity the dust grains are levitated by electrostatic fields and transported away from the surface in the near vacuum environment of the Moon The current dust charging and levitation models however do not fully explain the observed phenomena Since the abundance of dust on the Moon s surface with its observed adhesive characteristics has the potential of severe impact on human habitat and operations and lifetime of a variety of equipment it is necessary to investigate the charging properties and the lunar dust phenomena in order to develop appropriate mitigating strategies Photoelectric emission induced by the solar UV radiation with photon energies higher than the work function of the grain materials is recognized to be the dominant process for charging of the lunar dust and requires measurements of the photoelectric yields to determine the charging and equilibrium potentials of individual dust grains In this paper we present the first laboratory measurements of the photoelectric yields of individual sub-micron micron size dust grains selected from sample returns of

  20. Laboratory Observations of Self-Excited Dust Acoustic Shocks

    NASA Astrophysics Data System (ADS)

    Heinrich, J.; Kim, S.-H.; Merlino, R. L.

    2009-09-01

    Repeated, self-excited dust acoustic shock waves (DASWs) have been observed in a dc glow discharge dusty plasma using high-speed video imaging. Two major observations are reported: (1) The self-steepening of a nonlinear dust acoustic wave (DAW) into a saw-tooth wave with sharp gradient in dust density, very similar to those found in numerical solutions of the fully nonlinear fluid equations for a nondispersive DAW [B. Eliasson and P. K. Shukla, Phys. Rev. E 69, 067401 (2004)], and (2) the collision and confluence of two DASWs.

  1. Exploration Laboratory Analysis - ARC

    NASA Technical Reports Server (NTRS)

    Krihak, Michael K.; Fung, Paul P.

    2012-01-01

    The Exploration Laboratory Analysis (ELA) project supports the Exploration Medical Capability (ExMC) risk, Risk of Inability to Adequately Treat an Ill or Injured Crew Member, and ExMC Gap 4.05: Lack of minimally invasive in-flight laboratory capabilities with limited consumables required for diagnosing identified Exploration Medical Conditions. To mitigate this risk, the availability of inflight laboratory analysis instrumentation has been identified as an essential capability in future exploration missions. Mission architecture poses constraints on equipment and procedures that will be available to treat evidence-based medical conditions according to the Space Medicine Exploration Medical Conditions List (SMEMCL). The SMEMCL provided diagnosis and treatment for the evidence-based medical conditions and hence, a basis for developing ELA functional requirements.

  2. Laboratory Measurements of Charging of Apollo 17 Lunar Dust Grains by Low Energy Electrons

    NASA Technical Reports Server (NTRS)

    Abbas, Mian M.; Tankosic, Dragana; Spann, James F.; Dube, Michael J.; Gaskin, Jessica

    2007-01-01

    It is well recognized that the charging properties of individual micron/sub-micron size dust grains by various processes are expected to be substantially different from the currently available measurements made on bulk materials. Solar UV radiation and the solar wind plasma charge micron size dust grains on the lunar surface with virtually no atmosphere. The electrostatically charged dust grains are believed to be levitated and transported long distances over the lunar terminator from the day to the night side. The current models do not fully explain the lunar dust phenomena and laboratory measurements are needed to experimentally determine the charging properties of lunar dust grains. An experimental facility has been developed in the Dusty Plasma Laboratory at NASA Marshall Space Flight Center MSFC for investigating the charging properties of individual micron/sub-micron size positively or negatively charged dust grains by levitating them in an electrodynamic balance in simulated space environments. In this paper, we present laboratory measurements on charging of Apollo 17 individual lunar dust grains by low energy electron beams in the 5-100 eV energy range. The measurements are made by levitating Apollo 17 dust grains of 0.2 to 10 micrometer diameters, in an electrodynamic balance and exposing them to mono-energetic electron beams. The charging rates and the equilibrium potentials produced by direct electron impact and by secondary electron emission processes are discussed.

  3. Supernova Remnants As Laboratories For Determining The Properties Of Ejecta Dust And The Processing Of Dust Grains In Shocks

    NASA Astrophysics Data System (ADS)

    Dwek, Eli

    Recent infrared satellites, such as the Spitzer, Herschel, and WISE, have obtained a wealth of spectral and broadband data on the infrared (IR) emission from dust in supernova remnants (SNRs). Supernovae (SNe) are important producers of newly condensed dust during the early free-expansion phase of their evolution, and the dominant destroyers of dust during the subsequent remnant phase of their evolution. The infrared observations hold the key for determining their role in the origin and evolution of dust in the universe. We propose to model the composition, abundance, and size distribution of the dust in select Galactic and Magellanic Cloud remnants. As explained in detail below, the remnants were selected for the availability of IR and X-ray observations. All selected remnants have Spitzer IRS spectral data in the 5-35 μm regions which allow us to determine the effect of grain processing in the shock. Some have spectral maps that allow the distinction between the IR emission from SN-condensed and swept up circumstellar and interstellar dust. All remnants have also been covered by Spitzer, Herschel, and WISE imaging, and have existing X-ray Chandra and/or XMM observations. The dust in some remnants is radiatively-heated by a pulsar wind nebula, and in others collisionally- heated by shocked X-ray or line emitting gas. We will use physical models to calculate the radiative and collisional heating of SNR dust, the equilibrium or fluctuating dust temperatures, and the resulting IR emission for various dust compositions and size distributions. Specific examples of Cas A, SN1987A, the Crab Nebula, and Puppis A, are discussed in detail to illustrate our modeling approach. Our study will be the first comprehensive and physical analysis of a large sample of SNRs in different evolutionary states and different astrophysical environments. They will cover a wide range of interactions between the dust grains and their surroundings, including the radioactively- powered and

  4. Extraction and microanalysis of cosmic dust captured during sample return missions: laboratory simulations

    NASA Astrophysics Data System (ADS)

    Graham, G. A.; Kearsley, A. T.; Butterworth, A. L.; Bland, P. A.; Burchell, M. J.; McPhail, D. S.; Chater, R.; Grady, M. M.; Wright, I. P.

    2004-01-01

    Particles of cometary and asteroidal origin collected at source using dedicated capture cell technologies will be returned to Earth within the next 8 years. Furthermore, coincidental capture of interplanetary dust particles will occur on the exposed surfaces of the Genesis spacecraft. Laboratory simulations using both light-gas-gun and Van de Graaff accelerators have impacted dust analogues at velocities ranging from 5 km s -1 to ca. 72 km s -1 into comparable silicon and aerogel targets. Analysis of the impacts on silicon has shown complete spallation of impact residues for silicate projectiles of 38-53 μm in diameter, however craters formed by 1 μm iron projectiles show that near-intact residues can be preserved. An olivine grain embedded in aerogel has been characterized in situ using Raman micro-spectroscopy. Monte Carlo simulations and laboratory experiments have shown that analytical scanning electron microscopy can also be used to characterize embedded grains. Development of a novel particle extraction methodology using a 266 nm UV laser micro-dissection system has resulted in the recovery of an olivine grain. The extracted particle was then "cleaned up" using focused ion beam (FIB) milling to remove excess aerogel that was fused on the grain surface.

  5. Exploration Laboratory Analysis

    NASA Technical Reports Server (NTRS)

    Krihak, M.; Ronzano, K.; Shaw, T.

    2016-01-01

    The Exploration Laboratory Analysis (ELA) project supports the Exploration Medical Capability (ExMC) risk to minimize or reduce the risk of adverse health outcomes and decrements in performance due to in-flight medical capabilities on human exploration missions. To mitigate this risk, the availability of inflight laboratory analysis instrumentation has been identified as an essential capability for manned exploration missions. Since a single, compact space-ready laboratory analysis capability to perform all exploration clinical measurements is not commercially available, the ELA project objective is to demonstrate the feasibility of emerging operational and analytical capability as a biomedical diagnostics precursor to long duration manned exploration missions. The initial step towards ground and flight demonstrations in fiscal year (FY) 2015 was the down selection of platform technologies for demonstrations in the space environment. The technologies selected included two Small Business Innovation Research (SBIR) performers: DNA Medicine Institutes rHEALTH X and Intelligent Optical Systems later flow assays combined with Holomics smartphone analyzer. The selection of these technologies were based on their compact size, breadth of analytical capability and favorable ability to process fluids in a space environment, among several factors. These two technologies will be advanced to meet ground and flight demonstration success criteria and requirements that will be finalized in FY16. Also, the down selected performers will continue the technology development phase towards meeting prototype deliverables in either late 2016 or 2017.

  6. Exploration Laboratory Analysis

    NASA Technical Reports Server (NTRS)

    Krihak, M.; Ronzano, K.; Shaw, T.

    2016-01-01

    The Exploration Laboratory Analysis (ELA) project supports the Exploration Medical Capability (ExMC) risk to minimize or reduce the risk of adverse health outcomes and decrements in performance due to in-flight medical capabilities on human exploration missions. To mitigate this risk, the availability of inflight laboratory analysis instrumentation has been identified as an essential capability for manned exploration missions. Since a single, compact space-ready laboratory analysis capability to perform all exploration clinical measurements is not commercially available, the ELA project objective is to demonstrate the feasibility of emerging operational and analytical capability as a biomedical diagnostics precursor to long duration manned exploration missions. The initial step towards ground and flight demonstrations in fiscal year (FY) 2015 was the downselection of platform technologies for demonstrations in the space environment. The technologies selected included two Small Business Innovation Research (SBIR) performers: DNA Medicine Institute's rHEALTH X and Intelligent Optical System's lateral flow assays combined with Holomic's smartphone analyzer. The selection of these technologies were based on their compact size, breadth of analytical capability and favorable ability to process fluids in a space environment, among several factors. These two technologies will be advanced to meet ground and flight demonstration success criteria and requirements. The technology demonstrations and metrics for success will be finalized in FY16. Also, the downselected performers will continue the technology development phase towards meeting prototype deliverables in either late 2016 or 2017.

  7. Laboratory Studies of Optical Characteristics and Condensation Processes of Cosmic Dust Particles

    NASA Technical Reports Server (NTRS)

    Spann, J. F., Jr.; Abbas, M. M.; Venturini, C. C.

    2000-01-01

    Information about the optical characteristics and physical processes involving cosmic dust particles is vital for interpretation of astronomical observations and an understanding of the formation and processing of dust in the evolutionary cycle of matter in the interstellar medium. Cosmic dust particles are formed in a variety of astrophysical environments such as in cool stellar outflows and circumstellar envelopes. Definitive knowledge of the nature, composition, and physical processes of cosmic dust grains, however, can only be inferred from astronomical observations through laboratory experiments on the analogs of hypothesized dust particles and with modeling calculations. Laboratory investigations of the nature, composition, and optical characteristics of cosmic dust particles are being, carried out at many institutions with a variety of experimental techniques. Despite a wealth of available data, however, many basic issues remain unresolved. An experimental facility based on suspension of dust particles in electrodynamic balance in a pressure/temperature controlled environment in a cavity has been operational at the NASA Marshall Space Flight Center, and is currently being employed for studies of dust particle charging mechanisms using electron beams and with UV radiation. In this paper, we discuss two general classes of experiments under planning stages that may be simultaneously carried out on this facility for cosmic dust investigations (i) Infrared optical characteristics (extinction coefficients and scattering phase functions) of the analogs of hypothesized of cosmic dust particles, such as natural and synthetic amorphous silicates with varying compositions, amorphous carbon grains, polycyclic aromatic hydrocarbons (PAHs), and icy core-mantle particles etc. The initial spectral range under consideration is 1-25 micrometers, to be extended to the far infrared region in the future (ii) Condensation of volatile gases on nucleus dust particles to be

  8. Gait Analysis Laboratory

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Complete motion analysis laboratory has evolved out of analyzing walking patterns of crippled children at Stanford Children's Hospital. Data is collected by placing tiny electrical sensors over muscle groups of child's legs and inserting step-sensing switches in soles of shoes. Miniature radio transmitters send signals to receiver for continuous recording of abnormal walking pattern. Engineers are working to apply space electronics miniaturization techniques to reduce size and weight of telemetry system further as well as striving to increase signal bandwidth so analysis can be performed faster and more accurately using a mini-computer.

  9. Martian Dust Devils: Laboratory Simulations of Particle Threshold

    NASA Technical Reports Server (NTRS)

    Greeley, Ronald; Balme, Matthew R.; Iverson, James D.; Metzger, Stephen; Mickelson, Robert; Phoreman, Jim; White, Bruce

    2003-01-01

    An apparatus has been fabricated to simulate terrestrial and Martian dust devils. Comparisons of surface pressure profiles through the vortex core generated in the apparatus with both those in natural dust devils on Earth and those inferred for Mars are similar and are consistent with theoretical Rankine vortex models. Experiments to determine particle threshold under Earth ambient atmospheric pressures show that sand (particles > 60 micron in diameter) threshold is analogous to normal boundary-layer shear, in which the rotating winds of the vortex generate surface shear and hence lift. Lower-pressure experiments down to approx. 65 mbar follow this trend for sand-sized particles. However, smaller particles (i.e., dust) and all particles at very low pressures (w 10-60 mbar) appear to be subjected to an additional lift function interpreted to result from the strong decrease in atmospheric pressure centered beneath the vortex core. Initial results suggest that the wind speeds required for the entrainment of grains approx. 2 microns in diameter (i.e., Martian dust sizes) are about half those required for entrainment by boundary layer winds on both Earth and Mars.

  10. Martian dust devils: Laboratory simulations of particle threshold

    NASA Astrophysics Data System (ADS)

    Greeley, Ronald; Balme, Matthew R.; Iversen, James D.; Metzger, Stephen; Mickelson, Robert; Phoreman, Jim; White, Bruce

    2003-05-01

    An apparatus has been fabricated to simulate terrestrial and Martian dust devils. Comparisons of surface pressure profiles through the vortex core generated in the apparatus with both those in natural dust devils on Earth and those inferred for Mars are similar and are consistent with theoretical Rankine vortex models. Experiments to determine particle threshold under Earth ambient atmospheric pressures show that sand (particles > 60 μm in diameter) threshold is analogous to normal boundary-layer shear, in which the rotating winds of the vortex generate surface shear and hence lift. Lower-pressure experiments down to ~65 mbar follow this trend for sand-sized particles. However, smaller particles (i.e., dust) and all particles at very low pressures (~10-60 mbar) appear to be subjected to an additional lift function interpreted to result from the strong decrease in atmospheric pressure centered beneath the vortex core. Initial results suggest that the wind speeds required for the entrainment of grains ~2 μm in diameter (i.e., Martian dust sizes) are about half those required for entrainment by boundary layer winds on both Earth and Mars.

  11. Characterizing Dust from Cutting Corian®, a Solid-Surface Composite Material, in a Laboratory Testing System.

    PubMed

    Qi, Chaolong; Echt, Alan; Murata, Taichi K

    2016-06-01

    We conducted a laboratory test to characterize dust from cutting Corian(®), a solid-surface composite material, with a circular saw. Air samples were collected using filters and direct-reading instruments in an automatic laboratory testing system. The average mass concentrations of the total and respirable dusts from the filter samples were 4.78±0.01 and 1.52±0.01mg cm(-3), respectively, suggesting about 31.8% mass of the airborne dust from cutting Corian(®) is respirable. Analysis of the metal elements on the filter samples reveals that aluminum hydroxide is likely the dominant component of the airborne dust from cutting Corian(®), with the total airborne and respirable dusts containing 86.0±6.6 and 82.2±4.1% aluminum hydroxide, respectively. The results from the direct-reading instruments confirm that the airborne dust generated from cutting Corian(®) were mainly from the cutting process with very few particles released from the running circular saw alone. The number-based size distribution of the dusts from cutting Corian(®) had a peak for fine particles at 1.05 µm with an average total concentration of 871.9 particles cm(-3), and another peak for ultrafine particles at 11.8nm with an average total concentration of 1.19×10(6) particles cm(-3) The small size and high concentration of the ultrafine particles suggest additional investigation is needed to study their chemical composition and possible contribution to pulmonary effect.

  12. Dust emissions of organic soils observed in the field and laboratory

    NASA Astrophysics Data System (ADS)

    Zobeck, T. M.; Baddock, M. C.; Guo, Z.; Van Pelt, R.; Acosta-Martinez, V.; Tatarko, J.

    2011-12-01

    According to the U.S. Soil Taxonomy, Histosols (also known as organic soils) are soils that are dominated by organic matter (>20% organic matter) in half or more of the upper 80 cm. These soils, when intensively cropped, are subject to wind erosion resulting in loss in crop productivity and degradation of soil, air, and water quality. Estimating wind erosion on Histosols has been determined by USDA-Natural Resources Conservation Service as a critical need for the Wind Erosion Prediction System (WEPS) model. WEPS has been developed to simulate wind erosion on agricultural land in the US, including soils with organic soil material surfaces. However, additional field measurements are needed to calibrate and validate estimates of wind erosion of organic soils using WEPS. In this study, we used a field portable wind tunnel to generate suspended sediment (dust) from agricultural surfaces for soils with a range of organic contents. The soils were tilled and rolled to provide a consolidated, friable surface. Dust emissions and saltation were measured using an isokinetic vertical slot sampler aspirated by a regulated suction source. Suspended dust was collected on filters of the dust slot sampler and sampled at a frequency of once every six seconds in the suction duct using a GRIMM optical particle size analyzer. In addition, bulk samples of airborne dust were collected using a sampler specifically designed to collect larger dust samples. The larger dust samples were analyzed for physical, chemical, and microbiological properties. In addition, bulk samples of the soils were tested in a laboratory wind tunnel similar to the field wind tunnel and a laboratory dust generator to compare field and laboratory results. For the field wind tunnel study, there were no differences between the highest and lowest organic content soils in terms of their steady state emission rate under an added abrader flux, but the soil with the mid-range of organic matter had less emission by one third

  13. [Petrological Analysis of Astrophysical Dust Analog Evolution

    NASA Technical Reports Server (NTRS)

    Rietmeijer, Frans J. M.

    1997-01-01

    This project "Petrological analysis of astrophysical dust analog evolution" was initiated to try to understand the vapor phase condensation, and the nature of the reaction products, in circumstellar environments, such as the solar nebula 4,500 Myrs ago, and in the interstellar medium. Telescope-based infrared [IR] spectroscopy offers a broad-scale inventory of the various types of dust in these environments but no details on small-scale variations in terms of chemistry and morphology and petrological phase relationships. Vapor phase condensation in these environments is almost certainly a non-equilibrium process. The main challenge to this research was to document the nature of this process that, based on astrophysical observations, seems to yield compositionally consistent materials. This observation may suggest a predictable character during non-equilibrium condensation. These astrophysical environments include two chemically distinct, that is, oxygen-rich and carbon-rich environments. The former is characterized by silicates the latter by carbon-bearing solids. According to cosmological models of stellar evolution circumstellar dust accreted into protoplanets wherein thermal and/or aqueous processes will alter the dust under initially, non-equilibrium conditions.

  14. Laboratory Measurements of Optical Properties of Micron Size Individual Dust Grains

    NASA Technical Reports Server (NTRS)

    Abbas, M. M.; Craven, P. D.; Spann, J. F.; Tankosic, D.; LeClair, A.; Witherow, W. K.; Camata, R.; Gerakines, P.

    2003-01-01

    A laboratory program is being developed at NASA Marshall Space Flight Center for experimental determination of the optical and physical properties individual dust grains in simulated astrophysical environments. The experimental setup is based on an electrodynamic balance that permits levitation of single 0.1 - 10 micron radii dust grains in a cavity evacuated to pressures of approx. 10(exp -6) torr. The experimental apparatus is equipped with observational ports for measurements in the UV, visible, and infrared spectral regions. A cryogenic facility for cooling the particles to temperature of approx. 10-50K is being installed. The current and the planned measurements include: dust charging processes, photoelectric emissions and yields with UV irradiation, radiation pressure measurements, infrared absorption and scattering properties, and condensation processes, involving the analogs of cosmic dust grains. Selected results based on photoemissions, radiation pressure, and other laboratory measurements will be presented.

  15. Infrared spectroscopy of interplanetary dust in the laboratory

    NASA Technical Reports Server (NTRS)

    Fraundorf, P.; Patel, R. I.; Freeman, J. J.

    1981-01-01

    A mount containing three crushed chondritic interplanetary dust particles (IDPs) collected in the earth's stratosphere and subjected to infrared spectroscopic measurements shows features near 1000 and 500/cm, suggesting crystalline pyroxene rather than crystalline olivine, amorphous olivine, or meteoritic clay minerals. Chondritic IDP structural diversity and atmospheric heating effects must be considered when comparing this spectrum with interplanetary and cometary dust astrophysical spectra. TEM and infrared observations of one member of the rare subset of IDPs resembling hydrated carbonaceous chondrite matrix material shows a close infrared spectrum resemblance between 4000 and 400/cm to the C2 meteorite Murchison. TEM observations suggest that this class of particles may be used as an atmospheric entry heating-process thermometer.

  16. Analysis of IRAS solar system dust data

    NASA Technical Reports Server (NTRS)

    Dermott, S. F.; Nicholson, P. D.

    1991-01-01

    Data in the Infrared Astronomical Satellite (IRAS) Zodiacal History File were analyzed to extract dust band locations and peak brightness measurements from approximately 1,000 individual IRAS scans. The study had three goals. One was to show that the prominent solar system dust bands are associated with Hirayama asteroid families and thus that collisions between asteroids account for a significant fraction of the particles in the zodiacal cloud. Recent work suggests that while the Hirayama families are a major source of the dust in the bands, there may also be contributions from two or three smaller, more recently recognized asteroid families. A second goal was to show that there is evidence in the IRAS dust data for the transport of particles from asteroid belt to the Earth by Poynting-Robertson light drag and thus account for the fact that asteroid particles are collected in the Earth's stratosphere. Results of the study will confirm the location of the dust bands within the inner asteroid belt, and show conclusively that the material seen by IRAS is now spread over a wide range of distances from the sun. The third goal was to construct a model of the background zodiacal cloud that satisfies the proper dynamical constraints. Figures are provided to show the scans processed to remove zodiacal background and Galactic signals, and the resulting polynomial fits to the 25 micron scan. The latter provided objective estimates of band widths, peak locations, and peak fluxes. Modelling and analysis of the resulting band data has been presented at several conferences and is the subject of a number of forthcoming papers.

  17. Laboratory Studies of Charging Properties of Dust Grains in Astrophysical/Planetary Environments

    NASA Technical Reports Server (NTRS)

    Tankosic, D.; Abbas, M. M.

    2012-01-01

    the electron impact may lead to charging or discharging of dust grains depending upon the grain size, surface potential, electron energy, electron flux, grain composition, and configuration (e.g. Abbas et al, 2010). Laboratory measurements on charging of analogs of the interstellar dust as well as Apollo 11 dust grains conducted at the NASA-MSFC Dusty Plasma Lab. are presented here

  18. Laboratory Measurements of Optical and Physical Properties of Individual Lunar Dust Grains

    NASA Technical Reports Server (NTRS)

    Abbas, M. M.; Tankosic, D.; Craven, P. D.; Hoover, R. B.

    2006-01-01

    The lunar surface is covered with a thick layer of sub-micron/micron size dust grains formed by meteoritic impact over billions of years. The fine dust grains are levitated and transported on the lunar surface, and transient dust clouds over the lunar horizon were observed by experiments during the Apollo 17 mission. Theoretical models suggest that the dust grains on the lunar surface are charged by the solar UV radiation as well as the solar wind. Even without any physical activity, the dust grains are levitated by electrostatic fields and transported away from the surface in the near vacuum environment of the Moon. The current dust charging and levitation models, however, do not fully explain the observed phenomena. Since the abundance of dust on the Moon's surface with its observed adhesive characteristics has the potential of severe impact on human habitat and operations and lifetime of a variety of equipment, it is necessary to investigate the charging properties and the lunar dust phenomena in order to develop appropriate mitigating strategies. Photoelectric emission induced by the solar UV radiation with photon energies higher than the work function of the grain materials is recognized to be the dominant process for charging of the lunar dust, and requires measurements of the photoelectric yields to determine the charging and equilibrium potentials of individual dust grains. In this paper, we present the first laboratory measurements of the photoelectric yields of individual sub-micron/micron size dust grains selected from sample returns of Apollo 17, and Luna 24 missions, as well as similar size dust grains from the JSC-1 simulants. The experimental results were obtained on a laboratory facility based on an electrodynamic balance that permits a variety of experiments to be conducted on individual sub-micron/micron size dust grains in simulated space environments. The photoelectric emission measurements indicate grain size dependence with the yield

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

    PubMed

    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

  20. Risk analysis of dust explosion scenarios using Bayesian networks.

    PubMed

    Yuan, Zhi; Khakzad, Nima; Khan, Faisal; Amyotte, Paul

    2015-02-01

    In this study, a methodology has been proposed for risk analysis of dust explosion scenarios based on Bayesian network. Our methodology also benefits from a bow-tie diagram to better represent the logical relationships existing among contributing factors and consequences of dust explosions. In this study, the risks of dust explosion scenarios are evaluated, taking into account common cause failures and dependencies among root events and possible consequences. Using a diagnostic analysis, dust particle properties, oxygen concentration, and safety training of staff are identified as the most critical root events leading to dust explosions. The probability adaptation concept is also used for sequential updating and thus learning from past dust explosion accidents, which is of great importance in dynamic risk assessment and management. We also apply the proposed methodology to a case study to model dust explosion scenarios, to estimate the envisaged risks, and to identify the vulnerable parts of the system that need additional safety measures.

  1. Measurement of photoemission and secondary emission from laboratory dust grains

    NASA Technical Reports Server (NTRS)

    Hazelton, Robert C.; Yadlowsky, Edward J.; Settersten, Thomas B.; Spanjers, Gregory G.; Moschella, John J.

    1995-01-01

    The overall goal of this project is experimentally determine the emission properties of dust grains in order to provide theorists and modelers with an accurate data base to use in codes that predict the charging of grains in various plasma environments encountered in the magnetospheres of the planets. In general these modelers use values which have been measured on planar, bulk samples of the materials in question. The large enhancements expected due to the small size of grains can have a dramatic impact upon the predictions and the ultimate utility of these predictions. The first experimental measurement of energy resolved profiles of the secondary electron emission coefficient, 6, of sub-micron diameter particles has been accomplished. Bismuth particles in the size range of .022 to .165 micrometers were generated in a moderate pressure vacuum oven (average size is a function of oven temperature and pressure) and introduced into a high vacuum chamber where they interacted with a high energy electron beam (0.4 to 20 keV). Large enhancements in emission were observed with a peak value, delta(sub max) = 4. 5 measured for the ensemble of particles with a mean size of .022 micrometers. This is in contrast to the published value, delta(sub max) = 1.2, for bulk bismuth. The observed profiles are in general agreement with recent theoretical predictions made by Chow et al. at UCSD.

  2. Characteristics of Cometary Dust Tracks in Stardust Aerogel and Laboratory Calibrations

    NASA Technical Reports Server (NTRS)

    Burchell, M. J.; Fairey, S. A. J.; Wozniakiewicz, P.; Brownlee, D. E.; Hoerz, F.; Kearsley, A. T.; See, T. H.; Tsou, P.; Westphal, A.; Green, S. F.; Trigo-Rodriguez, J. M.; Dominguez, G.

    2007-01-01

    The cometary tray of the NASA Stardust spacecraft s aerogel collector has been examined to study the dust that was captured during the 2004 fly by of comet 81P/Wild-2. An optical scan of the entire collector surface revealed 256 impact features in the aerogel (width > 100 microns). 20 aerogel blocks (out of a total of 132) were removed from the collector tray for a higher resolution optical scan and 186 tracks were observed (track length > 50 microns and width > 8 microns). The impact features were classified into three types based on their morphology. Laboratory calibrations were conducted which reproduce all three types. This work suggests that the cometary dust consisted of some cohesive, relatively strong particles as well as particles with a more friable or low cohesion matrix containing smaller strong grains. The calibrations also permitted a particle size distribution to be estimated for the cometary dust. We estimate that approximately 1200 particles bigger than 1 micron struck the aerogel. The cumulative size distribution of the captured particles was obtained and compared with observations made by active dust detectors during the encounter. At large sizes (>20 microns) all measures of the dust are compatible, but at micrometer scales and smaller discrepancies exist between the various measurement systems which may reflect structure in the dust flux (streams, clusters etc.) along with some possible instrument effects.

  3. Laboratory evaluation to reduce respirable crystalline silica dust when cutting concrete roofing tiles using a masonry saw.

    PubMed

    Carlo, Rebecca V; Sheehy, John; Feng, H Amy; Sieber, William K

    2010-04-01

    Respirable crystalline silica dust exposure in residential roofers is a recognized hazard resulting from cutting concrete roofing tiles. Roofers cutting tiles using masonry saws can be exposed to high concentrations of respirable dust. Silica exposures remain a serious threat for nearly two million U.S. construction workers. Although it is well established that respiratory diseases associated with exposure to silica dust are preventable, they continue to occur and cause disability or death. The effectiveness of both a commercially available local exhaust ventilation (LEV) system and a water suppression system in reducing silica dust was evaluated separately. The LEV system exhausted 0.24, 0.13, or 0.12 m(3)/sec of dust laden air, while the water suppression system supplied 0.13, 0.06, 0.03, or 0.02 L/sec of water to the saw blade. Using a randomized block design, implemented under laboratory conditions, the aforementioned conditions were evaluated independently on two types of concrete roofing tiles (s-shape and flat) using the same saw and blade. Each engineering control (LEV or water suppression) was replicated eight times, or four times for each type of tile. Analysis of variance was performed by comparing the mean airborne respirable dust concentrations generated during each run and engineering control treatment. The use of water controls and ventilation controls compared with the "no control" treatment resulted in a statistically significant (p < 0.05) reduction of mean respirable dust concentrations generated per tile cut. The percent reduction for respirable dust concentrations was 99% for the water control and 91% for the LEV. Results suggest that water is an effective method for reducing crystalline silica exposures. However, water damage potential, surface discolorations, cleanup, slip hazards, and other requirements may make the use of water problematic in many situations. Concerns with implementing an LEV system to control silica dust exposures include

  4. Frontiers in In-Situ Cosmic Dust Detection and Analysis

    SciTech Connect

    Sternovsky, Zoltan; Auer, Siegfried; Drake, Keith; Gruen, Eberhard; Horanyi, Mihaly; Le, Huy; Xie Jianfeng; Srama, Ralf

    2011-11-29

    In-situ cosmic dust instruments and measurements played a critical role in the emergence of the field of dusty plasmas. The major breakthroughs included the discovery of {beta}-meteoroids, interstellar dust particles within the solar system, Jovian stream particles, and the detection and analysis of Enceladus's plumes. The science goals of cosmic dust research require the measurements of the charge, the spatial, size and velocity distributions, and the chemical and isotopic compositions of individual dust particles. In-situ dust instrument technology has improved significantly in the last decade. Modern dust instruments with high sensitivity can detect submicron-sized particles even at low impact velocities. Innovative ion optics methods deliver high mass resolution, m/dm>100, for chemical and isotopic analysis. The accurate trajectory measurement of cosmic dust is made possible even for submicron-sized grains using the Dust Trajectory Sensor (DTS). This article is a brief review of the current capabilities of modern dust instruments, future challenges and opportunities in cosmic dust research.

  5. Laboratory simulation and modeling of size, shape distributed interstellar graphite dust analogues: A comparative study

    NASA Astrophysics Data System (ADS)

    Boruah, Manash J.; Gogoi, Ankur; Ahmed, Gazi A.

    2016-06-01

    The computation of the light scattering properties of size and shape distributed interstellar graphite dust analogues using discrete dipole approximation (DDA) is presented. The light scattering properties of dust particles of arbitrary shapes having sizes ranging from 0.5 to 5.0 μm were computed using DDSCAT 7.3.0 software package and an indigenously developed post-processing tool for size and shape averaging. In order to model realistic samples of graphite dust and compute their light scattering properties using DDA, different target geometries were generated to represent the graphite particle composition in terms of surface smoothness, surface roughness and aggregation or their combination, for using as the target for DDSCAT calculations. A comparison of the theoretical volume scattering function at 543.5 nm and 632.8 nm incident wavelengths with laboratory simulation is also presented in this paper.

  6. Instrumental Analysis Chemistry Laboratory

    ERIC Educational Resources Information Center

    Munoz de la Pena, Arsenio; Gonzalez-Gomez, David; Munoz de la Pena, David; Gomez-Estern, Fabio; Sequedo, Manuel Sanchez

    2013-01-01

    designed for automating the collection and assessment of laboratory exercises is presented. This Web-based system has been extensively used in engineering courses such as control systems, mechanics, and computer programming. Goodle GMS allows the students to submit their results to a…

  7. Laboratory measurements of light scattering properties of a carbonaceous interstellar dust analogue (soot particles)

    NASA Astrophysics Data System (ADS)

    Gogoi, Ankur; Choudhury, Amarjyoti; Ahmed, Gazi A.; Kashyap Boruah, Goutam

    2012-07-01

    Dust particles are present everywhere in the solar system, cometary comae and tail, interstellar dust clouds, asteroidal atmospheres and aerosols of other planetary atmospheres. The in situ sampling of the cometary dust composition conducted by CIDA (Cometary and Interstellar Dust Analyzer) and observed interstellar extinction and polarization revealed the presence of amorphous carbon, graphite, silicate, graphite, carbonates, metal oxide grains, ice particles and nanodiamonds in the interstellar medium. These particles act as the heterogeneous media to scatter solar or steller light. Observations and simulations of the light scattered by dust particles in cometary comae, interplanetary space and planetary regolith (or analogous terrestrial dust aggregates) is necessary to deduce the physical properties of their constituent particles and may lead to a better understanding of the formation of solar system. Notably the measurement of the volume scattering function (VSF) and degree of linear polarization (DLP) can be used to estimate parameters like size, porosity and roughness of the dust particles. In this contribution we report the design and fabrication of a laser based laboratory light scattering instrument that uses an array of 16 static Si photodetectors and can be operated at three different incident wavelengths (543.5 nm, 594.5 nm and 632.8 nm). The accuracy and the reliability of the setup were verified by conducting light scattering measurements on spherical water droplets and comparing the results with theoretical Mie calculations. The results of the measurements of the VSF and DLP of carbonaceous soot particles (agglomerates) that were sprayed in front of the laser beam by using an aerosol sprayer are presented. The experimental results were further analyzed by comparing with theoretically generated T-matrix and DDA (Discrete Dipole Approximation) plots with estimated parameters to yield more fruitful conclusions. Significant variations of the light

  8. Laboratory analyses of meteoric debris in the upper stratosphere from settling bolide dust clouds

    NASA Astrophysics Data System (ADS)

    Rietmeijer, F. J. M.; Della Corte, V.; Ferrari, M.; Rotundi, A.; Brunetto, R.

    2016-03-01

    Bolide and fireball fragmentation produce vast amounts of dust that will slowly fall through the stratosphere. DUSTER (Dust in the Upper Stratosphere Tracking Experiment and Retrieval) was designed to intercept the nanometer to micrometer meteoric dust from these events for laboratory analyses while it is still in the upper stratosphere. This effort required extraordinary precautions to avoid particle contamination during collection and in the laboratory. Here we report dust from the upper stratosphere that was collected during two campaigns one in 2008 and another in 2011. We collected and characterized forty five uncontaminated meteoric dust particles. The collected particles are alumina, aluminosilica, plagioclase, fassaite, silica, CaCO3, CaO, extreme F-rich Csbnd Osbnd Ca particles, and oxocarbon particles. These particles are found in friable CI and CM carbonaceous chondrite, and unequilibrated ordinary chondrite meteoroids that are the most common source of bolides and fireballs. The oxocarbons have no meteorite counterparts. Some F-bearing CaCO3 particles changed shape when they interacted with the ambient laboratory atmosphere which might indicate their highly unequilibrated state as a result of fragmentation. Equilibrium considerations constrain the thermal regime experienced by the collected particles between ∼2000 °C and ∼1000 °C, as high as 3700 °C and as low as ∼650 °C after 9 s, followed by rapid quenching (μs) to below 1600 °C, but equilibrium conditions during these events is most unlikely. So far the observed thermal conditions in these events put the temperatures between ∼4300 °C and ∼430 °C for 5 s and high cooling rates. Such conditions are present in the immediate wake of meteors and fireballs.

  9. Instantaneous normal mode analysis of melting of finite dust clusters.

    PubMed

    Melzer, André; Schella, André; Schablinski, Jan; Block, Dietmar; Piel, Alexander

    2012-06-01

    The experimental melting transition of finite two-dimensional dust clusters in a dusty plasma is analyzed using the method of instantaneous normal modes. In the experiment, dust clusters are heated in a thermodynamic equilibrium from a solid to a liquid state using a four-axis laser manipulation system. The fluid properties of the dust cluster, such as the diffusion constant, are measured from the instantaneous normal mode analysis. Thereby, the phase transition of these finite clusters is approached from the liquid phase. From the diffusion constants, unique melting temperatures have been assigned to dust clusters of various sizes that very well reflect their dynamical stability properties.

  10. Laboratory Studies of the Optical Properties and Condensation Processes of Cosmic Dust Grains

    NASA Technical Reports Server (NTRS)

    Abbas, M. M.; Craven, P. D.; Spann, J. F.; Tankosic, D.; LeClair, A.; West, E.; Sheldon, R.; Witherow, W. K.; Gallagher, D. L.; Adrian, M. L.

    2002-01-01

    A laboratory facility for conducting a variety of experiments on single isolated dust particles of astrophysical interest levitated in an electrodynamics balance has been developed at NASA/Marshall Space Flight Center. The objective of the research is to employ this experimental technique for studies of the physical and optical properties of individual cosmic dust grains of 0.1-100 micron size in controlled pressure/temperatures environments simulating astrophysical conditions. The physical and optical properties of the analogs of interstellar and interplanetary dust grains of known composition and size distribution will be investigated by this facility. In particular, we will carry out three classes of experiments to study the micro-physics of cosmic dust grains. (1) Charge characteristics of micron size single dust grains to determine the photoelectric efficiencies, yields, and equilibrium potentials when exposed to UV radiation. (2) Infrared optical properties of dust particles (extinction coefficients and scattering phase functions) in the 1-30 micron region using infrared diode lasers and measuring the scattered radiation. (3) Condensation experiments to investigate the condensation of volatile gases on colder nucleated particles in dense interstellar clouds and lower planetary atmospheres. The condensation experiments will involve levitated nucleus dust grains of known composition and initial mass (or m/q ratio), cooled to a temperature and pressure (or scaled pressure) simulating the astrophysical conditions, and injection of a volatile gas at a higher temperature from a controlled port. The increase in the mass due to condensation on the particle will be monitored as a function of the dust particle temperature and the partial pressure of the injected volatile gas. The measured data will permit determination of the sticking coefficients of volatile gases and growth rates of dust particles of astrophysical interest. Some preliminary results based on

  11. A comparison of two laboratories for the measurement of wood dust using button sampler and diffuse reflection infrared Fourier-transform spectroscopy (DRIFTS).

    PubMed

    Chirila, Madalina M; Sarkisian, Khachatur; Andrew, Michael E; Kwon, Cheol-Woong; Rando, Roy J; Harper, Martin

    2015-04-01

    The current measurement method for occupational exposure to wood dust is by gravimetric analysis and is thus non-specific. In this work, diffuse reflection infrared Fourier transform spectroscopy (DRIFTS) for the analysis of only the wood component of dust was further evaluated by analysis of the same samples between two laboratories. Field samples were collected from six wood product factories using 25-mm glass fiber filters with the Button aerosol sampler. Gravimetric mass was determined in one laboratory by weighing the filters before and after aerosol collection. Diffuse reflection mid-infrared spectra were obtained from the wood dust on the filter which is placed on a motorized stage inside the spectrometer. The metric used for the DRIFTS analysis was the intensity of the carbonyl band in cellulose and hemicellulose at ~1735 cm(-1). Calibration curves were constructed separately in both laboratories using the same sets of prepared filters from the inhalable sampling fraction of red oak, southern yellow pine, and western red cedar in the range of 0.125-4 mg of wood dust. Using the same procedure in both laboratories to build the calibration curve and analyze the field samples, 62.3% of the samples measured within 25% of the average result with a mean difference between the laboratories of 18.5%. Some observations are included as to how the calibration and analysis can be improved. In particular, determining the wood type on each sample to allow matching to the most appropriate calibration increases the apparent proportion of wood dust in the sample and this likely provides more realistic DRIFTS results.

  12. Laboratory Studies of the Optical Properties and Condensation Processes of Cosmic Dust Particles

    NASA Technical Reports Server (NTRS)

    Abbas, Mian M.; Craven, Paul D.; Spann, James F.; Tankosic, Dragana; Six, N. Frank (Technical Monitor)

    2002-01-01

    A laboratory facility for levitating single isolated dust particles in an electrodynamics balance has been developing at NASA/Marshall Space Flight Center for conducting a variety of experimental, of astrophysical interest. The objective of this research is to employ this innovative experimental technique for studies of the physical and optical properties of the analogs of cosmic grains of 0.2-10 micron size in a chamber with controlled pressure/temperatures simulating astrophysical environments. In particular, we will carry out three classes of experiments to investigate the microphysics of the analogs of interstellar and interplanetary dust grains. (1) Charge characteristics of micron size single dust grains to determine the photoelectric efficiencies, yields, and equilibrium potentials when exposed to UV radiation. These measurements will provide the much-needed photoelectric emission data relating to individual particles as opposed to that for the bulk materials available so far. (2) Infrared optical properties of dust particles obtained by irradiating the particles with radiation from tunable infrared diode lasers and measuring the scattered radiation. Specifically, the complex refractive indices, the extinction coefficients, the scattering phase functions, and the polarization properties of single dust grains of interest in interstellar environments, in the 1-25 micron spectral region will be determined. (3) Condensation experiments to investigate the deposition of volatile gases on colder nucleated particles in dense interstellar clouds and lower planetary atmospheres. The increase in the mass or m/q ratio due to condensation on the particle will be monitored as a function of the dust particle temperature and the partial pressure of the injected volatile gas. The measured data wild permit determination of the sticking efficiencies of volatile gases of astrophysical interest. Preliminary results based on photoelectric emission experiments on 0.2-6.6 micron

  13. Instrument Synthesis and Analysis Laboratory

    NASA Technical Reports Server (NTRS)

    Wood, H. John

    2004-01-01

    The topics addressed in this viewgraph presentation include information on 1) Historic instruments at Goddard; 2) Integrated Design Capability at Goddard; 3) The Instrument Synthesis and Analysis Laboratory (ISAL).

  14. Lab Analysis of Dust Wipe Samples

    EPA Pesticide Factsheets

    Dust wipe samples collected on residential properties near the fenceline of KCBX North and South Terminals in Chicago, which store and handle pet coke, were analyzed for polycyclic aromatic hydrocarbons (PAHs) and trace metals and minerals.

  15. The IAA cosmic dust laboratory: Experimental scattering matrices of clay particles

    NASA Astrophysics Data System (ADS)

    Muñoz, O.; Moreno, F.; Guirado, D.; Ramos, J. L.; Volten, H.; Hovenier, J. W.

    2011-01-01

    We present the first results of measurements on solid particles performed at the Instituto de Astrofı´sica de Andalucı´a (IAA) cosmic dust laboratory located in Granada, Spain. The laboratory apparatus measures the complete scattering matrix as a function of the scattering angle of aerosol particles. The measurements can be performed at a wavelength ( λ) of 483, 488, 520, 568, or 647 nm in the scattering angle range from 3° to 177°. Results of special test experiments are presented which show that our experimental results for scattering matrices are not significantly contaminated by multiple scattering and that the sizes/shapes of the particles do not change during the measurements. Moreover, the measured scattering matrix for a sample of green clay particles is compared with measurements previously performed in the Amsterdam light scattering setup for the same sample. New measurements on a white clay sample at 488 and 647 nm are also presented. The apparatus is devoted to experimentally studying the angle dependence of scattering matrices of dust samples of astrophysical interest. Moreover, there is a great interest in similar studies of aerosols that can affect the radiative balance of the atmosphere of the Earth and other planets such as silicates, desert dust, volcanic ashes, and carbon soot particles.

  16. Laboratory evaluation of dust-control effectiveness of pen surface treatments for cattle feedlots.

    PubMed

    Guo, Li; Maghirang, Ronaldo G; Razote, Edna B; Auvermann, Brent W

    2011-01-01

    Emission of particulate matter (PM) is one of the major air quality concerns for large beef cattle feedlots. Effective treatments on the uncompacted soil and manure mixture of the pen surface may help in reducing PM emission from feedlots. A laboratory apparatus was developed for measuring dust-emission potential of cattle feedlot surfaces as affected by pen surface treatments. The apparatus was equipped with a simulated pen surface, four mock cattle hooves, and samplers for PM with equivalent aerodynamic diam. ≤ 10 μm (PM(10)). The simulated pen surface had a layer of dry, loose feedlot manure with a compacted soil layer underneath. Mock hooves were moved horizontally on the manure layer to simulate horizontal action of cattle hooves on the pen surface. High-volume PM samplers were used to collect emitted dust. Effects of hoof speed, depth of penetration, and surface treatments with independent candidate materials (i.e., sawdust, wheat straw, hay, rubber mulch, and surface water application) on PM(10) emission potential of the manure layer were investigated. Our laboratory study showed PM(10) emission potential increased with increasing depth of penetration and hoof speed. Of the surface treatments evaluated, application of water (6.4 mm) and hay (723 g m(-2)) exhibited the greatest percentage reduction in PM(10) emission potential (69 and 77%, respectively) compared with the untreated manure layer. This study indicated application of hay or other mulch materials on the pen surface might be good alternative methods to control dust emission from cattle feedlots.

  17. Radiative transfer modeling of dust-coated Pancam calibration target materials: Laboratory visible/near-infrared spectrogoniometry

    USGS Publications Warehouse

    Johnson, J. R.; Sohl-Dickstein, J.; Grundy, W.M.; Arvidson, R. E.; Bell, J.F.; Christensen, P.R.; Graff, T.; Guinness, E.A.; Kinch, K.; Morris, Robert; Shepard, M.K.

    2006-01-01

    Laboratory visible/near-infrared multispectral observations of Mars Exploration Rover Pancam calibration target materials coated with different thicknesses of Mars spectral analog dust were acquired under variable illumination geometries using the Bloomsburg University Goniometer. The data were fit with a two-layer radiative transfer model that combines a Hapke formulation for the dust with measured values of the substrate interpolated using a He-Torrance approach. We first determined the single-scattering albedo, phase function, opposition effect width, and amplitude for the dust using the entire data set (six coating thicknesses, three substrates, four wavelengths, and phase angles 3??-117??). The dust exhibited single-scattering albedo values similar to other Mars analog soils and to Mars Pathfinder dust and a dominantly forward scattering behavior whose scattering lobe became narrower at longer wavelengths. Opacity values for each dust thickness corresponded well to those predicted from the particles sizes of the Mars analog dust. We then restricted the number of substrates, dust thicknesses, and incidence angles input to the model. The results suggest that the dust properties are best characterized when using substrates whose reflectances are brighter and darker than those of the deposited dust and data that span a wide range of dust thicknesses. The model also determined the dust photometric properties relatively well despite limitations placed on the range of incidence angles. The model presented here will help determine the photometric properties of dust deposited on the MER rovers and to track the multiple episodes of dust deposition and erosion that have occurred at both landing sites. Copyright 2006 by the American Geophysical Union.

  18. Preliminary analysis of cometary dust trails

    NASA Technical Reports Server (NTRS)

    Sykes, M. V.; Hunten, D. M.; Low, F. J.

    1986-01-01

    Dust trails are observed in the orbits of some short-period comets. Large particles, having diameters in the submillimeter range and larger, are ejected by these comets into orbits close to that of the parent comet. By considering the effects of ejection and radiation forces, the spread of particles of different diameters along a parent comet's orbit, both ahead and behind the comet in mean anomaly were modeled. Using this model, the ages of the dust trail material associated with P/Tempel 2, P/Gunn, P/Encke, and P/Schwassmann-Wachmann 1 were estimated; they are found to consist of emissions occurring over a minimum of one to a few orbital periods. It also becomes possible to constrain the particle diameters in a trail segment forward of a comet's orbital position. Such a forward extension is observed in the Tempel 2 and Gunn dust trails, but not the Encke and S-W 1 dust trails. Relative particle sizes among these trails are discussed. The Tempel 2 dust trail is found to have an excess of particles with diameters greater than 1 mm.

  19. Exploration Laboratory Analysis FY13

    NASA Technical Reports Server (NTRS)

    Krihak, Michael; Perusek, Gail P.; Fung, Paul P.; Shaw, Tianna, L.

    2013-01-01

    The Exploration Laboratory Analysis (ELA) project supports the Exploration Medical Capability (ExMC) risk, which is stated as the Risk of Inability to Adequately Treat an Ill or Injured Crew Member, and ExMC Gap 4.05: Lack of minimally invasive in-flight laboratory capabilities with limited consumables required for diagnosing identified Exploration Medical Conditions. To mitigate this risk, the availability of inflight laboratory analysis instrumentation has been identified as an essential capability in future exploration missions. Mission architecture poses constraints on equipment and procedures that will be available to treat evidence-based medical conditions according to the Space Medicine Exploration Medical Conditions List (SMEMCL), and to perform human research studies on the International Space Station (ISS) that are supported by the Human Health and Countermeasures (HHC) element. Since there are significant similarities in the research and medical operational requirements, ELA hardware development has emerged as a joint effort between ExMC and HHC. In 2012, four significant accomplishments were achieved towards the development of exploration laboratory analysis for medical diagnostics. These achievements included (i) the development of high priority analytes for research and medical operations, (ii) the development of Level 1 functional requirements and concept of operations documentation, (iii) the selection and head-to-head competition of in-flight laboratory analysis instrumentation, and (iv) the phase one completion of the Small Business Innovation Research (SBIR) projects under the topic Smart Phone Driven Blood-Based Diagnostics. To utilize resources efficiently, the associated documentation and advanced technologies were integrated into a single ELA plan that encompasses ExMC and HHC development efforts. The requirements and high priority analytes was used in the selection of the four in-flight laboratory analysis performers. Based upon the

  20. Ice nucleation by different types of soil dusts under mixed-phase cloud conditions: Laboratory studies and atmospheric implications

    NASA Astrophysics Data System (ADS)

    Tobo, Y.; DeMott, P. J.; Hill, T. C. J.; Prenni, A. J.; Swoboda-Colberg, N. G.; Franc, G. D.; Kreidenweis, S. M.

    2014-12-01

    It has been suggested that ice nucleation by desert soil dusts composed largely of minerals plays an important role in forming ice crystals in mixed-phase clouds and subsequent precipitation. More recently, several studies have suggested that soil dusts having higher contents of soil organic matter (SOM) may also contribute significantly to atmospheric ice nucleation. In this study, we examine the ice nucleation properties of soil dusts derived from different locations in the world. Our results show that the ice nucleating ability of agricultural soil dusts derived from the largest dust source regions in North America is almost comparable to that of desert soil dusts at temperatures colder than about -15°C. We also confirm that the agricultural soil dusts can serve as effective ice nuclei (IN) at much warmer temperatures. On the other hand, our results indicate that the ice nucleating ability of the agricultural soil dusts is significantly reduced after H2O2 digestion, while the reduction is not significant for the desert soil dusts. In this regard, based on single particle analysis, we demonstrate that such a significant reduction observed in the agricultural soil dusts is mainly attributable to the removal of organic-rich particles (namely, SOM particles), which have much higher ice nucleating ability than mineral particles. Moreover, we discuss the potential contributions of these soil dusts to atmospheric IN populations.

  1. Laboratory Experiments on Rotation of Micron Size Cosmic Dust Grains with Radiation

    NASA Technical Reports Server (NTRS)

    Abbas, M. M.; Craven, P. D.; Spann, J. F.; Tankosic, D.; LeClair, A.; Gallagher, D. L.; West, E.; Weingartner, J.; Witherow, W. K.

    2004-01-01

    The processes and mechanisms involved in the rotation and alignment of interstellar dust grains have been of great interest in astrophysics ever since the surprising discovery of the polarization of starlight more than half a century ago. Numerous theories, detailed mathematical models and numerical studies of grain rotation and alignment along the Galactic magnetic field have been presented in the literature. In particular, the subject of grain rotation and alignment by radiative torques has been shown to be of particular interest in recent years. However, despite many investigations, a satisfactory theoretical understanding of the processes involved in grain rotation and alignment has not been achieved. As there appears to be no experimental data available on this subject, we have carried out some unique experiments to illuminate the processes involved in rotation of dust grains in the interstellar medium. In this paper we present the results of some preliminary laboratory experiments on the rotation of individual micron/submicron size nonspherical dust grains levitated in an electrodynamic balance evacuated to pressures of approx. 10(exp -3) to 10(exp -5) torr. The particles are illuminated by laser light at 5320 A, and the grain rotation rates are obtained by analyzing the low frequency (approx. 0-100 kHz) signal of the scattered light detected by a photodiode detector. The rotation rates are compared with simple theoretical models to retrieve some basic rotational parameters. The results are examined in the light of the current theories of alignment.

  2. Laboratory Experiments on Rotation and Alignment of the Analogs of Interstellar Dust Grains by Radiation

    NASA Technical Reports Server (NTRS)

    Abbas, M. M.; Craven, P. D.; Spann, J. F.; Tankosic, D.; LeClair, A.; Gallagher, D. L.; West, E. A.; Weingartner, J. C.; Witherow, W. K.; Tielens, A. G. G. M.

    2004-01-01

    The processes and mechanisms involved in the rotation and alignment of interstellar dust grains have been of great interest in astrophysics ever since the surprising discovery of the polarization of starlight more than half a century ago. Numerous theories, detailed mathematical models and numerical studies of grain rotation and alignment with respect to the Galactic magnetic field have been presented in the literature. In particular, the subject of grain rotation and alignment by radiative torques has been shown to be of particular interest in recent years. However, despite many investigations, a satisfactory theoretical understanding of the processes involved in grain rotation and alignment has not been achieved. As there appears to be no experimental data available on this subject, we have carried out some unique experiments to illuminate the processes involved in rotation of dust grains in the interstellar medium. In this paper we present the results of some preliminary laboratory experiments on the rotation of individual micron/submicron size nonspherical dust grains levitated in an electrodynamic balance evacuated to pressures of approximately 10(exp -3) to 10(exp -5) torr. The particles are illuminated by laser light at 5320 Angstroms, and the grain rotation rates are obtained by analyzing the low frequency (approximately 0-100 kHz) signal of the scattered light detected by a photodiode detector. The rotation rates are compared with simple theoretical models to retrieve some basic rotational parameters. The results are examined in the light of the current theories of alignment.

  3. Laboratory Experiments on Rotation and Alignment of the Analogs of Interstellar Dust Grains by Radiation

    NASA Technical Reports Server (NTRS)

    Abbas, M. M.; Craven, P. D.; Spann, J. F.; Tankosic, D.; LeClair, A.; Gallagher, D. L.; West, E. A.; Weingartner, J. C.; Witherow, W. K.; Tielens, A. G. G. M.

    2004-01-01

    The processes and mechanisms involved in the rotation and alignment of interstellar dust grains have been of great interest in astrophysics ever since the surprising discovery of the polarization of starlight more than half a century ago. Numerous theories, detailed mathematical models, and numerical studies of grain rotation and alignment with respect to the Galactic magnetic field have been presented in the literature. In particular, the subject of grain rotation and alignment by radiative torques has been shown to be of particular interest in recent years. However, despite many investigations, a satisfactory theoretical understanding of the processes involved in subject, we have carried out some unique experiments to illuminate the processes involved in the rotation of dust grains in the interstellar medium. In this paper we present the results of some preliminary laboratory experiments on the rotation of individual micron/submicron-sized, nonspherical dust grains levitated in an electrodynamic balance evacuated to pressures of approximately 10(exp -3) to 10(exp -5) torr. The particles are illuminated by laser light at 5320 A, and the grain rotation rates are obtained by analyzing the low-frequency (approximately 0 - 100 kHz) signal of the scattered light detected by a photodiode detector. The rotation rates are compared with simple theoretical models to retrieve some basic rotational parameters. The results are examined in light of the current theories of alignment.

  4. Workshop on the Analysis of Interplanetary Dust Particles

    NASA Technical Reports Server (NTRS)

    Zolensky, Michael E. (Editor)

    1994-01-01

    Great progress has been made in the analysis of interplanetary dust particles (IDP's) over the past few years. This workshop provided a forum for the discussion of the following topics: observation and modeling of dust in the solar system, mineralogy and petrography of IDP's, processing of IDP's in the solar system and terrestrial atmosphere, comparison of IDP's to meteorites and micrometeorites, composition of IDP's, classification, and collection of IDP's.

  5. In-Flight Laboratory Analysis

    NASA Technical Reports Server (NTRS)

    Baumann, David; Perusek, Gail; Nelson, Emily; Krihak, Michael; Brown, Dan

    2012-01-01

    One-year study objectives align with HRP requirements. HRP requirements include measurement panels for research and medical operations - These measurement panels are distinctly different. Instrument requirements are defined - Power, volume and mass not quite a critical limitation as for medical operations (deep space exploration missions). One-year evaluation goals will lead HHC towards in-flight laboratory analysis capability.

  6. Carbon and silicate grains in the laboratory as analogues of cosmic dust.

    PubMed

    Mennella, V; Brucato, J R; Colangeli, L

    2001-03-15

    Carbon and silicate grains are the two main components of cosmic dust. There is increasing spectroscopic evidence that their composition varies according to the cosmic environment and the experienced processing. Irradiation from ultraviolet photons and cosmic rays, as well as chemical interactions with the interstellar gas play a crucial role for grain transformation. The study of 'laboratory analogues' represents a powerful tool to better understand the nature and evolution of cosmic materials. In particular, simulations of grain processing are fundamental to outline an evolutionary pathway for interstellar particles. In the present work, we discuss the ultraviolet and infrared spectral changes induced by thermal annealing, ultraviolet irradiation, ion irradiation and hydrogen atom bombardment in carbon and silicate analogue materials. The laboratory results give the opportunity to shed light on the long-standing problems of the attribution of ultraviolet and infrared interstellar spectral features.

  7. Nature of the Organic Signature in Dust from the Interstellar Medium: Laboratory Analog Studies

    NASA Technical Reports Server (NTRS)

    Freund, M. M.; Freund, F. T.; Staple, A.; Scoville, J.

    2002-01-01

    We measured the infrared (IR) nu(sub CH) absorption bands around 3.4 microns (2800 - 3000 cm(sup -1) in large laboratory-grown magnesium oxide (MgO) and natural olivine single crystals that crystallized from CO/CO2/H2O saturated melts. These bands are very similar to those from many astronomical sources, such as from dust in the diffuse interstellar medium (ISM), from the outflow of evolved stars, etc., and they are characteristic of aliphatic -CH2- and -CH3 entities. In our laboratory single crystals the VCH bands arise from C-H entities that were introduced by a solid solution process, and that are imbedded in the mineral matrix in form of polyatomic C(sub n) entities with C atoms bonded to O and to H. Heating breaks the C-H bonds, causing hydrogen to disperse in the mineral matrix. C-H bonds are re-established rapidly during annealing. We propose that dust grains probably contain the same type of internal C(sub n)-H entities in solid matrix rather than an external organic layer covering the grain surfaces. Thermodynamical arguments show that the concentration of organics in solid solution in small grains can be comparable to that found in astronomical environments.

  8. Inferential Source Attribution from Dust: Review and Analysis.

    PubMed

    Stoney, D A; Bowen, A M; Stoney, P L

    2013-03-01

    The analysis of dust allows inference of exposures to geographical areas, environments, activities, and processes. This activity of inferential source attribution is distinguished from that of comparative source attribution, where the focus is on the degree of correspondence between two sources in relation to other possible sources. Review of source attribution efforts in the forensic and broader scientific literature shows that most efforts are limited in one or more of four principal ways, which are classified as: (a) methods based on attribution by direct comparison; (b) methods based on closed-set item classification; (c) analysis using restricted methods and characteristics, and (d) requirement of a large sample size. These limitations provide the context for the requirements of more generalized inferential source attribution. Occurring much more rarely, and almost exclusively in the forensic literature, are individual source attribution case reports that have a microscopical, multidisciplinary perspective. Collectively these are an excellent illustration of potential and their common features demonstrate that (a) a diversity of laboratory expertise and methodology is required in order for source attribution to be successful; (b) different tools need to be applied in different cases, and (c) a process must be in place that allows a facile choice among this diversity of tools, in response to the particular investigative problem and the specifics of the samples that are available. Alternative collaborative mechanisms are considered and recommendations are made for related research and programmatic application.

  9. Laboratory studies of immersion and deposition mode ice nucleation of ozone aged mineral dust particles

    NASA Astrophysics Data System (ADS)

    Kanji, Z. A.; Welti, A.; Chou, C.; Stetzer, O.; Lohmann, U.

    2013-04-01

    Ice nucleation in the atmosphere is central to the understanding the microphysical properties of mixed-phase and cirrus clouds. Ambient conditions such as temperature (T) and relative humidity (RH), as well as aerosol properties such as chemical composition and mixing state play an important role in predicting ice formation in the troposphere. Previous field studies have reported the absence of sulphate and organic compounds on mineral dust ice crystal residuals sampled at mountain top stations or aircraft based measurements despite the long range transport mineral dust is subjected to. We present laboratory studies of ice nucleation for immersion and deposition mode on ozone aged mineral dust particles for 233 < T < 263 K that will represent ageing but not internal mixing with in(organic) compounds. Heterogeneous ice nucleation of untreated kaolinite (Ka) and Arizona Test Dust (ATD) particles is compared to corresponding aged particles that are subjected to ozone exposures of 0.4-4.3 ppmv in a stainless steel aerosol tank. The portable ice nucleation counter (PINC) and immersion chamber combined with the Zurich ice nucleation chamber (IMCA - ZINC) are used to conduct deposition and immersion mode measurements respectively. Ice active fractions as well as ice active surface site densities (ns) are reported and observed to increase as a function of temperature. We present first results that demonstrate enhancement of the ice nucleation ability of aged mineral dust particles in both the deposition and immersion mode due to ageing. Additionally, these are also the first results to show a suppression of heterogeneous ice nucleation without the condensation of a coating of (in)organic material. In immersion mode, low exposure Ka particles showed enhanced ice activity requiring a median freezing temperature of 1.5 K warmer than that of untreated Ka whereas high exposure ATD particles showed suppressed ice nucleation requiring a median freezing temperature of 3 K colder

  10. Laboratory studies of immersion and deposition mode ice nucleation of ozone aged mineral dust particles

    NASA Astrophysics Data System (ADS)

    Kanji, Z. A.; Welti, A.; Chou, C.; Stetzer, O.; Lohmann, U.

    2013-09-01

    Ice nucleation in the atmosphere is central to the understanding the microphysical properties of mixed-phase and cirrus clouds. Ambient conditions such as temperature (T) and relative humidity (RH), as well as aerosol properties such as chemical composition and mixing state play an important role in predicting ice formation in the troposphere. Previous field studies have reported the absence of sulfate and organic compounds on mineral dust ice crystal residuals sampled at mountain top stations or aircraft based measurements despite the long-range transport mineral dust is subjected to. We present laboratory studies of ice nucleation for immersion and deposition mode on ozone aged mineral dust particles for 233 < T < 263 K. Heterogeneous ice nucleation of untreated kaolinite (Ka) and Arizona Test Dust (ATD) particles is compared to corresponding aged particles that are subjected to ozone concentrations of 0.4-4.3 ppmv in a stainless steel aerosol tank. The portable ice nucleation counter (PINC) and immersion chamber combined with the Zurich ice nucleation chamber (IMCA-ZINC) are used to conduct deposition and immersion mode measurements, respectively. Ice active fractions as well as ice active surface site densities (ns) are reported and observed to increase as a function of decreasing temperature. We present first results that demonstrate enhancement of the ice nucleation ability of aged mineral dust particles in both the deposition and immersion mode due to ageing. We also present the first results to show a suppression of heterogeneous ice nucleation activity without the condensation of a coating of (in)organic material. In immersion mode, low ozone exposed Ka particles showed enhanced ice activity requiring a median freezing temperature of 1.5 K warmer than that of untreated Ka, whereas high ozone exposed ATD particles showed suppressed ice nucleation requiring a median freezing temperature of 3 K colder than that of untreated ATD. In deposition mode, low

  11. ChemCam analysis of Martian fine dust

    NASA Astrophysics Data System (ADS)

    Lasue, Jeremie; Mangold, Nicolas; Cousin, Agnes; Meslin, Pierre-Yves; Wiens, Roger; Gasnault, Olivier; Rapin, William; Schroder, Susanne; Ollila, Ann; Fabre, Cécile; Berger, Gilles; Le Mouélic, Stéphane; Dehouck, Erwin; Forni, Olivier; Maurice, Sylvestre; Anderson, Ryan; Bridges, Nathan; Clark, Benton; Clegg, Samuel; d'Uston, Claude; Goetz, Walter; Johnson, Jeffrey R.; Lanza, Nina; Madsen, Morten; Melikechi, Noureddine; Newsom, Horton; Sautter, Violaine; Martin-Torres, Javier; Zorzano, Maria-Paz; MSL Science Team

    2016-10-01

    In this work, we examine the chemical composition of dust observed by the Chemistry Camera (ChemCam) instrument onboard the Mars Science Laboratory (MSL) rover at Gale Crater. The Laser Induced Breakdown Spectroscopy technique analyses samples without preparation, which allows detection of the elemental composition of surface deposits. Mars aeolian fine dust (<2-3 microns) composition is analyzed on the first shot of each Mars target. It is reproducible over time and present a composition characteristic of the global martian fine dust, which covers the entire planet and contributes to the local geology analyzed by MSL. Its composition can also be retrieved on the ChemCam Calibration Targets (CCCT) by subtraction of the well characterized CCCT spectra. The CCCT include eight glasses and ceramics that have been generated to simulate Martian rocks of interest and two targets of a single element (graphite for carbon and an alloy of titanium). ChemCam passive spectroscopy also indicates varying deposition of the dust cover on the CCCT.Major elements are quantified and shown to be very similar to the fine soils encountered at Gale crater. The composition is also similar to the soils and fine dust measured by APXS for the elements common to both instruments. The minor elements quantified by ChemCam (Ba, Sr, Rb, Li, Mn, Cr) are within the range of soil surveys, but we see a higher concentration of Li than in other types of remotely characterized targets. Sulfur is possibly detected at the ChemCam limit of detection. Hydrogen is clearly identified, indicating that this fine dust is a contributor to the H content of the martian soils, as also detected by the SAM and CheMin instruments, and provides constraints as to which fraction of the Martian surface is hydrated and altered. In conclusion, the finest fraction of dust particles on the surface of Mars contains hydrated components mixed intimately within the fine aeolian dust fraction, suggesting that this dust likely

  12. Laboratory simulation of intact capture of cometary and asteroidal dust particles in ISAS

    NASA Technical Reports Server (NTRS)

    Fujiwara, A.; Nakamura, A.; Kadono, T.

    1994-01-01

    In order to develop a collector for intact capturing of cometary dust particles in the SOCCER mission and regolith dust particles released from asteroid surfaces by the impact of projectiles launched from a flying-by spacecraft, various kinds of materials as the collector candidates have been exposed to hypervelocity projectiles in our laboratory. Data based on the penetration characteristics of various materials (penetration depth, hole profile, effectiveness for intact capturing) are greatly increased. The materials tested for these simulation experiments include various kinds of low-density media and multisheet stacks; these are foamed plastics (polystyrene 0.01 g/cc), silica aerogels (0.04 g/cc), air (0.001 g/cc), liquid, and multisheet stack consisting of thin Al sheets (thickness 0.002 to 0.1 mm) or polyethylene sheets. Projectiles used are spheres or cylinders of nylon, polycarbonate, basalt, copper, iron, and volatile organics (e.g.,paradichlorobenzene) of size ranging from 30 micrometers to 1 cm launched by a two-stage light gas gun and a rail gun in ISAS at velocity up to about 7 km/s. Some results obtained by using nylon projectiles of velocity less than about 5 km/s are presented; the penetration depth vs. bulk density of the collector material for several kinds of materials and the velocity at which the projectiles begin to fragment vs. material density for foamed polystyrene.

  13. Laboratory simulation of intact capture of cometary and asteroidal dust particles in ISAS

    NASA Astrophysics Data System (ADS)

    Fujiwara, A.; Nakamura, A.; Kadono, T.

    In order to develop a collector for intact capturing of cometary dust particles in the SOCCER mission and regolith dust particles released from asteroid surfaces by the impact of projectiles launched from a flying-by spacecraft, various kinds of materials as the collector candidates have been exposed to hypervelocity projectiles in our laboratory. Data based on the penetration characteristics of various materials (penetration depth, hole profile, effectiveness for intact capturing) are greatly increased. The materials tested for these simulation experiments include various kinds of low-density media and multisheet stacks; these are foamed plastics (polystyrene 0.01 g/cc), silica aerogels (0.04 g/cc), air (0.001 g/cc), liquid, and multisheet stack consisting of thin Al sheets (thickness 0.002 to 0.1 mm) or polyethylene sheets. Projectiles used are spheres or cylinders of nylon, polycarbonate, basalt, copper, iron, and volatile organics (e.g.,paradichlorobenzene) of size ranging from 30 micrometers to 1 cm launched by a two-stage light gas gun and a rail gun in ISAS at velocity up to about 7 km/s. Some results obtained by using nylon projectiles of velocity less than about 5 km/s are presented; the penetration depth vs. bulk density of the collector material for several kinds of materials and the velocity at which the projectiles begin to fragment vs. material density for foamed polystyrene.

  14. Instrument study of the Lunar Dust eXplorer (LDX) for a lunar lander mission II: Laboratory model calibration

    NASA Astrophysics Data System (ADS)

    Li, Yanwei; Strack, Heiko; Bugiel, Sebastian; Wu, Yiyong; Srama, Ralf

    2015-10-01

    A dust trajectory detector placed on the lunar surface is exposed to extend people's knowledge on the dust environment above the lunar surface. The new design of Lunar Dust eXplorer (LDX) is well suited for lunar or asteroid landers with a broad range of particle charges (0.1-10 fC), speeds (few m s-1 to few km s-1) and sizes (0.1-10 μ m). The calibration of dust trajectory detector is important for the detector development. We do present experimental results to characterize the accuracy of the newly developed LDX laboratory model. Micron sized iron particles were accelerated to speed between 0.5 and 20 km s-1 with primary charges larger than 1 fC. The achieved accuracies of the detector are ± 5 % and ± 7 % for particle charge and speed, respectively. Dust trajectories can be determined with measurement accuracy better than ± 2°. A dust sensor of this type is suited for the exploration of the surface of small bodies without an atmosphere like the Earth's moon or asteroids in future, and the minisatellites are also suitable carriers for the study of interplanetary dust and manned debris on low Earth orbits.

  15. Laboratory Measurements on Charging of Individual Micron-Size Apollo-11 Dust Grains by Secondary Electron Emissions

    NASA Technical Reports Server (NTRS)

    Tankosic, D.; Abbas, M. M.

    2012-01-01

    Observations made during Apollo missions, as well as theoretical models indicate that the lunar surface and dust grains are electrostatically charged, levitated and transported. Lunar dust grains are charged by UV photoelectric emissions on the lunar dayside and by the impact of the solar wind electrons on the nightside. The knowledge of charging properties of individual lunar dust grains is important for developing appropriate theoretical models and mitigating strategies. Currently, very limited experimental data are available for charging of individual micron-size size lunar dust grains in particular by low energy electron impact. However, experimental results based on extensive laboratory measurements on the charging of individual 0.2-13 micron size lunar dust grains by the secondary electron emissions (SEE) have been presented in a recent publication. The SEE process of charging of micron-size dust grains, however, is found to be very complex phenomena with strong particle size dependence. In this paper we present some examples of the complex nature of the SEE properties of positively charged individual lunar dust grains levitated in an electrodynamic balance (EDB), and show that they remain unaffected by the variation of the AC field employed in the above mentioned measurements.

  16. 7 CFR 160.17 - Laboratory analysis.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Laboratory analysis. 160.17 Section 160.17 Agriculture... STANDARDS FOR NAVAL STORES Methods of Analysis, Inspection, Sampling and Grading § 160.17 Laboratory analysis. The analysis and laboratory testing of naval stores shall be conducted, so far as is...

  17. 7 CFR 160.17 - Laboratory analysis.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Laboratory analysis. 160.17 Section 160.17 Agriculture... STANDARDS FOR NAVAL STORES Methods of Analysis, Inspection, Sampling and Grading § 160.17 Laboratory analysis. The analysis and laboratory testing of naval stores shall be conducted, so far as is...

  18. 7 CFR 160.17 - Laboratory analysis.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Laboratory analysis. 160.17 Section 160.17 Agriculture... STANDARDS FOR NAVAL STORES Methods of Analysis, Inspection, Sampling and Grading § 160.17 Laboratory analysis. The analysis and laboratory testing of naval stores shall be conducted, so far as is...

  19. Laboratory measurement of optical constants of solid SiO and application to circumstellar dust

    NASA Astrophysics Data System (ADS)

    Wetzel, S.; Klevenz, M.; Gail, H.-P.; Pucci, A.; Trieloff, M.

    2013-05-01

    Context. Silicate minerals belong to the most abundant solids that form in cosmic environments. Their formation requires that a sufficient number of oxygen atoms per silicon atom are freely available. For the standard cosmic element mixture this can usually be taken for granted, but it becomes a problem at the transition from the oxygen-rich chemistry of M-stars to the carbon-rich chemistry of C-stars. In the intermediate type S-stars, most of the oxygen and carbon is consumed by formation of CO and SiO molecules, and left-over oxygen to build SiO4-tetrahedrons in solids becomes scarce. Under such conditions SiO molecules from the gas phase may condense into solid SiO. The infrared absorption spectrum of solid SiO differs from that of normal silicates by the absence of Si-O-Si bending modes around 18 μm whereas the absorption band due to Si-O bond stretching modes at about 10 μm is present. Observations show that exactly this particular characteristic can be found in some S-star spectra. Aims: We demonstrate that this observation may be explained by the formation of solid SiO as a major dust component at C/O abundance ratios close to unity. Methods: The infrared absorption properties of solid SiO are determined by laboratory transmission measurements of thin films of SiO produced by vapour deposition on a Si(111) wafer in the range between 100 cm-1 and 5000 cm-1 (2 μm and 100 μm). From the measured spectra the dielectric function of SiO is derived by using a Brendel-oscillator model, particularly suited to the representation of optical properties of amorphous materials. The results are used in model calculations of radiative transfer in circumstellar dust shells with solid SiO dust in order to determine the spectral features due to SiO dust. Results: Comparison of synthetic and observed spectra shows that reasonable agreement is obtained between the main spectral characteristics of emission bands due to solid silicon monoxide and an emission band centred on 10

  20. Composition, size distribution, optical properties, and radiative effects of laboratory-resuspended PM10 from geological dust of the Rome area, by electron microscopy and radiative transfer modelling

    NASA Astrophysics Data System (ADS)

    Pietrodangelo, A.; Salzano, R.; Bassani, C.; Pareti, S.; Perrino, C.

    2015-11-01

    In this work, new information has been gained on the laboratory-resuspended PM10 fraction from geological topsoil and outcropped rocks representative of the Rome area (Latium). Mineralogical composition, size distribution, optical properties and the surface radiative forcing efficiency (RFE) of dust types representing the compositional end members of this geological area have been addressed. A multi-disciplinary approach was used, based on chamber resuspension of raw materials and sampling of the PM10 fraction, to simulate field sampling at dust source, scanning electron microscopy/X-ray energy-dispersive microanalysis (SEM XEDS) of individual mineral particles, X-ray diffraction (XRD) analysis of bulk dust samples, building of number and volume size distribution (SD) from microanalysis data of mineral particles and fitting to a log-normal curve, and radiative transfer modelling (RTM) to retrieve optical properties and radiative effects of the compositional end-member dust samples. The mineralogical composition of Rome lithogenic PM10 varies between an end-member dominated by silicate minerals (from volcanics lithotypes), and one mostly composed of calcite (from travertine or limestones). Lithogenic PM10 with intermediate composition derives mainly from siliciclastic rocks or marlstones. Size and mineral species of PM10 particles of silicate-dominated dust types are tuned mainly by rock weathering and, to lesser extent, by debris formation or crystallization; chemical precipitation of CaCO3 plays a major role in calcite-dominated types. These differences are reflected in the diversity of volume distributions, either within dust types or mineral species. Differences are also observed between volume distributions of calcite from travertine (natural source; SD unimodal at 5 μm a.d.) and from road dust (anthropic source; SD bimodal at 3.8 and 1.8 μm a.d.). The volcanics and travertine dusts differently affect the single scattering albedo (SSA) and the asymmetry

  1. Absorbing Aerosols: Field and Laboratory Studies of Black Carbon and Dust

    NASA Astrophysics Data System (ADS)

    Aiken, A. C.; Flowers, B. A.; Dubey, M. K.

    2011-12-01

    Currently, absorbing aerosols are thought to be the most uncertain factor in atmospheric climate models (~0.4-1.2 W/m2), and the 2nd most important factor after CO2 in global warming (1.6 W/m2; Ramanathan and Carmichael, Nature Geoscience, 2008; Myhre, Science, 2009). While most well-recognized atmospheric aerosols, e.g., sulfate from power-plants, have a cooling effect on the atmosphere by scattering solar radiation, black carbon (BC or soot) absorbs sunlight strongly which results in a warming of the atmosphere. Dust particles are also present globally and can absorb radiation, contributing to a warmer and drier atmosphere. Direct on-line measurements of BC and hematite, an absorbing dust aerosol, can be made with the Single Particle Soot Photometer (SP2), which measures the mass of the particles by incandescence on an individual particle basis. Measurements from the SP2 are combined with absorption measurements from the three-wavelength photoacoustic soot spectrometer (PASS-3) at 405, 532, and 781 nm and the ultraviolet photoacoustic soot spectrometer (PASS-UV) at 375 nm to determine wavelength-dependent mass absorption coefficients (MACs). Laboratory aerosol samples include flame-generated soot, fullerene soot, Aquadag, hematite, and hematite-containing dusts. Measured BC MAC's compare well with published values, and hematite MAC's are an order of magnitude less than BC. Absorbing aerosols measured in the laboratory are compared with those from ambient aerosols measured during the Las Conchas fire and BEACHON-RoMBAS. The Las Conchas fire was a wildfire in the Jemez Mountains of New Mexico that burned over 100,000 acres during the Summer of 2011, and BEACHON-RoMBAS (Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics & Nitrogen - Rocky Mountain Biogenic Aerosol Study) is a field campaign focusing on biogenic aerosols at the Manitou Forest Observatory near Colorado Springs, CO in Summer 2011. Optical properties and size

  2. Laboratory Analysis of Silicate Stardust Grains of Diverse Stellar Origins

    NASA Technical Reports Server (NTRS)

    Nguyen, Ann N.; Keller, Lindsay P.; Nakamura-Messenger, Keiko

    2016-01-01

    Silicate dust is ubiquitous in a multitude of environments across the cosmos, including evolved oxygen-rich stars, interstellar space, protoplanetary disks, comets, and asteroids. The identification of bona fide silicate stardust grains in meteorites, interplanetary dust particles, micrometeorites, and dust returned from comet Wild 2 by the Stardust spacecraft has revolutionized the study of stars, interstellar space, and the history of dust in the Galaxy. These stardust grains have exotic isotopic compositions that are records of nucleosynthetic processes that occurred in the depths of their now extinct parent stars. Moreover, the chemical compositions and mineralogies of silicate stardust are consequences of the physical and chemical nature of the stellar condensation environment, as well as secondary alteration processes that can occur in interstellar space, the solar nebula, and on the asteroid or comet parent body in which they were incorporated. In this talk I will discuss our use of advanced nano-scale instrumentation in the laboratory to conduct coordinated isotopic, chemical, and mineralogical analyses of silicate stardust grains from AGB stars, supernovae, and novae. By analyzing the isotopic compositions of multiple elements in individual grains, we have been able to constrain their stellar sources, explore stellar nucleosynthetic and mixing processes, and Galactic chemical evolution. Through our mineralogical studies, we have found these presolar silicate grains to have wide-ranging chemical and mineral characteristics. This diversity is the result of primary condensation characteristics and in some cases secondary features imparted by alteration in space and in our Solar System. The laboratory analysis of actual samples of stars directly complements astronomical observations and astrophysical models and offers an unprecedented level of detail into the lifecycles of dust in the Galaxy.

  3. Heterogeneous reactions of NO2 and HNO3 on oxides and mineral dust: A combined laboratory and modeling study

    NASA Astrophysics Data System (ADS)

    Underwood, G. M.; Song, C. H.; Phadnis, M.; Carmichael, G. R.; Grassian, V. H.

    2001-08-01

    This study combines laboratory measurements and modeling analysis to quantify the role of heterogeneous reactions of gaseous nitrogen dioxide and nitric acid on mineral oxide and mineral dust particles in tropospheric ozone formation. At least two types of heterogeneous reactions occur on the surface of these particles. Upon initial exposure of the oxide to NO2 there is a loss of NO2 from the gas phase by adsorption on the particle surface, i.e., NO2(g) → NO2(a). As the reaction proceeds, a reduction of gaseous NO2 to NO, NO2 (g) → NO (g) is found to occur. Initial uptake coefficients γ0 for NO2 on the surface of these particles have been measured at 298 K using a Knudsen cell reactor coupled to a mass spectrometer. For the oxides studied, α,γ-Al2O3, α,γ-Fe2O3, TiO2, SiO2, CaO, and MgO, γ0 ranges from <4×10-10 for SiO2 to 2×10-5 for CaO with most values in the 10-6 range. For authentic samples of China loess and Saharan sand, similar reactivity to the oxides is observed with γ0 values of 2×10-6 and 1×10-6, respectively. For HNO3 the reactivity is 1-2 orders of magnitude higher. Using these laboratory measurements, the impact of heterogeneous reactions of NO2 and HNO3 on mineral dust in tropospheric ozone formation and on O3-precursor relationships is assessed using a time-dependent, multiphase chemistry box model. Simulations with and without heterogeneous reactions were conducted to evaluate the possible influence of these heterogeneous reactions on ambient levels. Results show that values of the initial uptake for NO2 and HNO3, adjusted for roughness effects, must be greater than 10-4 to have an appreciable impact on NOx, HNO3, and O3 concentrations for the conditions modeled here. Thus the measured uptake coefficients for NO2 on dry surfaces are just below the lower limit to have an impact on the photochemical oxidant cycle, while the heterogeneous reactivity of HNO3 is sufficiently large to have an effect. Under conditions of high mineral dust

  4. Experimental setup for the laboratory investigation of micrometeoroid ablation using a dust accelerator

    NASA Astrophysics Data System (ADS)

    Thomas, Evan; Simolka, Jonas; DeLuca, Michael; Horányi, Mihály; Janches, Diego; Marshall, Robert A.; Munsat, Tobin; Plane, John M. C.; Sternovsky, Zoltan

    2017-03-01

    A facility has been developed to simulate the ablation of micrometeoroids in laboratory conditions. An electrostatic dust accelerator is used to generate iron particles with velocities of 10-70 km/s. The particles are then introduced into a chamber pressurized with a target gas, where the pressure is adjustable between 0.01 and 0.5 Torr, and the particle partially or completely ablates over a short distance. An array of biased electrodes above and below the ablation path is used to collect the generated ions/electrons with a spatial resolution of 2.6 cm along the ablating particles' path, thus allowing the study of the spatiotemporal evolution of the process. For completely ablated particles, the total collected charge directly yields the ionization coefficient of a given dust material-target gas combination. The first results of this facility measured the ionization coefficient of iron atoms with N2, air, CO2, and He target gases for impact velocities >20 km/s, and are reported by Thomas et al. [Geophys. Res. Lett. 43, 3645 (2016)]. The ablation chamber is also equipped with four optical ports that allow for the detection of the light emitted by the ablating particle. A multichannel photomultiplier tube system is used to observe the ablation process with a spatial and temporal resolution of 0.64 cm and 90 ns. The preliminary results indicate that it is possible to calculate the velocity of the ablating particle from the optical observations, and in conjunction with the spatially resolved charge measurements allow for experimental validation of ablation models in future studies.

  5. [Laboratory chemical analysis in ascites].

    PubMed

    Satz, N

    1991-04-13

    Chemical analysis of ascitic fluid may be helpful in determining the underlying disease. We discuss the diagnostic accuracy of the common and newer chemical parameters (protein, LDH, lactate, glucose, cholesterol, triglycerides, phospholipids, fibronectin, albumin gradient [value of serum minus value of ascites], ferritin, tumor markers, immunomodulators, leukocytes, bacterial and cytologic examinations). We also review the pathogenesis and clinical findings of the most frequent ascites forms (benign hepatic, infective, malignant ascites, ascites associated with liver metastases or hepatocellular carcinoma, cardiac and pancreatic ascites) and the most important diagnosis criteria. In the malignant ascites a high cholesterol, a narrow albumin gradient or a high ferritin value have high diagnostic accuracy, but diagnosis is by the finding of malignant cells. For the diagnosis of infective ascites, bacteriology is mandatory even though the results are negative in most cases, particularly in spontaneous bacterial peritonitis where diagnosis has to be established clinically, by a low pH or by a high leukocyte count. Benign hepatic ascites is diagnosed by demonstrating an underlying chronic liver disease and laboratory examinations of the peritoneal fluid to exclude other causes. The laboratory tests in ascites associated with liver metastases or with hepatocellular carcinoma were similar to those in benign hepatic ascites and the two ascites forms must be separated by other clinical and technical findings. Pancreatic ascites can easily be distinguished from the other forms by the high amylase and lipase content.

  6. The evaluation of the dust-related occupational respiratory disorders of dental laboratory technicians working in Denizli Province

    PubMed Central

    Yurdasal, Belkıs; Bozkurt, Nurgül; Bozkurt, Ali İhsan; Yilmaz, Özlem

    2015-01-01

    INTRODUCTION: Dental laboratory technicians (DLTs) get exposed to fibrinogen dusts that are very risky dusts in terms of health. In this study, respiration complaints, pneumoconiosis frequencies and working conditions of the dental technicians in Denizli were investigated. METHODS: All of the registered DLTs working in Denizli were included in the study. A 30-item questionnaire was used to gather data about the participants and their working environments. Then, pulmonary function tests (PFTs) were carried out and standard chest X-rays were taken in order to detect how much the respiratory systems of the workers were affected. Standard chest X-rays were evaluated according to International Labour Organizations classification. Depending on the screening results, technicians who were found to have had pathologies and suspected cases were examined. “High-resolution computerized tomography (HRCT)” was taken from those who were found to have pathology in their chest X-rays and they were evaluated according to the classification of Hering et al. RESULTS: There are a total of 166 DLTs working in Denizli Province participated in the study. One hundred and forty-three (86.1%) of the participants were male, and 23 of them were female. The mean age of the participants is 33.5 ± 8.1. Average working time of the workers is 16 years. Total exposure time was calculated 36,177 h. Approximately, 56% of workers were smokers. When the working conditions were considered, it was found that 98.8% of laboratories had a ventilation system. Technicians’ use of personal protective equipment is low. Participants’ often or continuous use of masks, gloves, goggles, and vacuum device was found 69%, 36%, 47%, and 63% respectively while working. About 21.2% of the technicians have respiratory symptoms while 15.2% of them have eye complaints. At the analysis of PFT results, 27.7% restrictive type pulmonary disorder was determined. At the analysis of chest X-rays; 1/0 profusion sub

  7. The Life Cycle of Dust in the Universe: Observations, Theory, and Laboratory Experiments

    NASA Astrophysics Data System (ADS)

    Kemper, Ciska; Andersen, Anja; Baes, Maarten; Gomez, Haley; Watson, Darach

    This meeting addresses the life cycle of dust in the Universe, which covers the formation, evolution and destruction of dust in a range of environments, ranging from the smallest to the largest scales. Bringing together observational and theoretical astrophysicists as well as meteoriticists and experimentalists allows for a cross-disciplinary dialogue. The meeting follows a successful tradition of astrophysical dust meetings, starting in Albany in 1972, with the latest edition "Cosmic Dust: Near and Far" organized by Th. Henning taking place in Heidelberg in 2008. Since that meeting, the field of dust astrophysics has made major leaps forward with the host of data arriving from such missions as the infrared space telescopes Spitzer and Herschel, and the sample return mission, Stardust, which took dust samples from comet Wild-2. The largest telescope on Earth, ALMA, has also recently come online, allowing for investigations into the origin of dust in the Universe, making this is excellent time to review the status of the field of dust astrophysics. The meeting aims to create an environment in which all aspects of the life cycle of dust are discussed, from an astrophysical, chemical and mineralogical perspective, and its effect on a range of environments. Observational insights, theoretical models and experimental approaches all contribute to our view of the life cycle of dust, and the meeting addresses new developments and future projects in all these areas.

  8. Dust biasing of damped Lyman alpha systems: a Bayesian analysis

    NASA Astrophysics Data System (ADS)

    Pontzen, Andrew; Pettini, Max

    2009-02-01

    If damped Lyman alpha systems (DLAs) contain even modest amounts of dust, the ultraviolet luminosity of the background quasar can be severely diminished. When the spectrum is redshifted, this leads to a bias in optical surveys for DLAs. Previous estimates of the magnitude of this effect are in some tension; in particular, the distribution of DLAs in the (NHI, Z) (i.e. column density-metallicity) plane has led to claims that we may be missing a considerable fraction of metal-rich, high column density DLAs, whereas radio surveys do not unveil a substantial population of otherwise hidden systems. Motivated by this tension, we perform a Bayesian parameter estimation analysis of a simple dust obscuration model. We include radio and optical observations of DLAs in our overall likelihood analysis and show that these do not, in fact, constitute conflicting constraints. Our model gives statistical limits on the biasing effects of dust, predicting that only 7 per cent of DLAs are missing from optical samples due to dust obscuration; at 2σ confidence, this figure takes a maximum value of 17 per cent. This contrasts with recent claims that DLA incidence rates are underestimated by 30-50 per cent. Optical measures of the mean metallicities of DLAs are found to underestimate the true value by just 0.1dex (or at most 0.4dex,2σ confidence limit), in agreement with the radio survey results of Akerman et al. As an independent test, we use our model to make a rough prediction for dust reddening of the background quasar. We find a mean reddening in the DLA rest frame of log10 ~= -2.4 +/- 0.6, consistent with direct analysis of the Sloan Digital Sky Survey (SDSS) quasar population by Vladilo et al., log10 = -2.2 +/- 0.1. The quantity most affected by dust biasing is the total cosmic density of metals in DLAs, ΩZ,DLA, which is underestimated in optical surveys by a factor of approximately 2.

  9. On the isotope analysis of cometary dust

    NASA Technical Reports Server (NTRS)

    Begemann, Friedrich

    1989-01-01

    It is thought that comets are an intimate mixture of ices and sub-micron to pebble sized silicates. Based on experience with carbonaceous chrondrites, part of the smallest grains are expected to be primary condensates carrying the unadulterated isotopic signature of their place of origin. In order to extract this information a grain-by-grain analysis will be necessary.

  10. Analysis of Interplanetary Dust Experiment Detectors and Other Witness Plates

    NASA Technical Reports Server (NTRS)

    Griffis, D. P.; Wortman, J. J.

    1992-01-01

    The development of analytical procedures for identifying the chemical composition of residue from impacts that occurred on the Interplanetary Dust Experiment (IDE) detectors during the flight of Long Duration Exposure Facility (LDEF) and the carrying out of actual analysis on IDE detectors and other witness plates are discussed. Two papers on the following topics are presented: (1) experimental analysis of hypervelocity microparticle impact sites on IDE sensor surfaces; and (2) contaminant interfaces with secondary Ion Mass Spectrometer (SIMS) analysis of microparticle impactor residues on LDEF surfaces.

  11. 7 CFR 160.17 - Laboratory analysis.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) NAVAL STORES REGULATIONS AND STANDARDS FOR NAVAL STORES Methods of Analysis, Inspection, Sampling and Grading § 160.17 Laboratory analysis. The analysis and laboratory testing of naval stores shall be conducted, so far as is...

  12. Linear and nonlinear analysis of dust acoustic waves in dissipative space dusty plasmas with trapped ions

    NASA Astrophysics Data System (ADS)

    El-Hanbaly, A. M.; El-Shewy, E. K.; Sallah, M.; Darweesh, H. F.

    2015-05-01

    The propagation of linear and nonlinear dust acoustic waves in a homogeneous unmagnetized, collisionless and dissipative dusty plasma consisted of extremely massive, micron-sized, negative dust grains has been investigated. The Boltzmann distribution is suggested for electrons whereas vortex-like distribution for ions. In the linear analysis, the dispersion relation is obtained, and the dependence of damping rate of the waves on the carrier wave number , the dust kinematic viscosity coefficient and the ratio of the ions to the electrons temperatures is discussed. In the nonlinear analysis, the modified Korteweg-de Vries-Burgers (mKdV-Burgers) equation is derived via the reductive perturbation method. Bifurcation analysis is discussed for non-dissipative system in the absence of Burgers term. In the case of dissipative system, the tangent hyperbolic method is used to solve mKdV-Burgers equation, and yield the shock wave solution. The obtained results may be helpful in better understanding of waves propagation in the astrophysical plasmas as well as in inertial confinement fusion laboratory plasmas.

  13. Quantitative analysis on windblown dust concentrations of PM10 (PM2.5) during dust events in Mongolia

    NASA Astrophysics Data System (ADS)

    Jugder, Dulam; Shinoda, Masato; Kimura, Reiji; Batbold, Altangerel; Amarjargal, Danzansambuu

    2014-09-01

    Dust concentration, wind speed and visibility, measured at four sites in the Gobi Desert and at a site in the steppe zone of Mongolia over a period of 4.5 years (January 2009 to May 2013), have been analyzed for their relationships, their effects on visibility, and for an estimate of the threshold wind necessary for dust emission in the region. Based on quantitative analysis on measurements, we evaluated that dust emission concentrations of 41-61 (20-24) μg m-3 of PM10 (PM2.5) are as the criterion between normal and hazy atmospheric conditions. With the arrival of dust events, wind-borne soil particulate matter (PM10, PM2.5) that originates in the Gobi Desert is changed dramatically. PM10 (PM2.5) concentrations increase by at least double or by several tens of times during severe dust events in comparison with the normal atmospheric condition. Ratio (PM2.5/PM10) between monthly means of PM10 and PM2.5 concentrations showed that anthropogenic particles were dominant in the ambient air of province centers in cool months (November to February). Threshold values of the onset of dust events were determined for PM10 (PM2.5) concentrations. According to the definition of dust storms, dust concentrations of PM10 corresponding to visibility of 1 km or less were determined at sites in the Gobi Desert and the steppe region. The threshold wind speeds during days with dust events were estimated at four sites in the Gobi Desert and compared each other. The threshold wind was higher at Sainshand and its cause might be due to smaller silt and clay fractions of soil.

  14. Laboratory study of PCB transport from primary sources to settled dust

    EPA Science Inventory

    Transport of house dust and Arizona Test Dust on polychlorinated biphenyl (PCB)-containing panels and PCB-free panels was investigated in a 30-m3 stainless steel chamber. The PCB-containing panels were aluminum sheets coated with a PCB-spiked, oil-based primer or two-part polysul...

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

    DOE PAGES

    DeMott, P. J.; Prenni, A. J.; McMeeking, G. R.; ...

    2014-06-27

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

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

    DOE PAGES

    DeMott, P. J.; Prenni, A. J.; McMeeking, G. R.; ...

    2015-01-13

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

  17. The Cosmic DUNE dust astronomy mission

    NASA Astrophysics Data System (ADS)

    Grun, E.; Srama, R.; Cosmic Dune Team

    A dust astronomy mission aims at the simultaneous measurement of the origin and the chemical composition of individual dust grains in space. Interstellar dust traversing the solar system constitutes the galactic solid phase of matter from which stars and planetary systems form. Interplanetary dust, from comets and asteroids, represents remnant material from bodies at different stages of early solar system evolution. Thus, studies of interstellar and interplanetary dust with Cosmic DUNE (Cosmic Dust Near Earth) will provide a comparison between the composition of the interstellar medium and primitive planetary objects. Cosmic DUNE will prepare the way for effective collection in near-Earth space of interstellar and interplanetary dust for subsequent return to Earth and analysis in laboratories. Cosmic DUNE establishes the next logical step beyond NASA's Stardust mission, with four major advancements in cosmic dust research: (1) Analysis of the elemental and isotopic composition of individual cosmic dust grains, (2) determination of the size distribution of interstellar dust, (3) characterization of the interstellar dust flow through the planetary system, and (4) analysis of interplanetary dust of cometary and asteroidal origin. This mission goal will be reached with novel dust instrumentation. A dust telescope trajectory sensor has been developed which is capable of obtaining precision trajectories of sub-micron sized particles in space. A new high mass resolution dust analyzer of 0.1m2 impact area can cope with the low fluxes expected in interplanetary space. Cosmic DUNE will be proposed to ESA in response to its upcoming call for mission ideas.

  18. Source Characterization of African Dust Using CCSEM Analysis

    NASA Astrophysics Data System (ADS)

    Rogers, R.; Hunt, A.; Oldfield, F.

    2013-12-01

    A preliminary investigation is underway to determine whether African dust is developed through Pedogenic or Aeolian processes. 85 dust samples were taken from the Sahel and Saharan region of Africa and analyzed using computer controlled scanning electron microscopy (CCSEM). Optimized secondary electron detectors (SED) and back-scattered electron detectors (BSED) with adjustable quadrants was used with a light element Peltier-cooled energy dispersive x-ray spectrometer. A variable pressure system was utilized for the analysis of insulating materials, which eliminated the need for special specimen coating to dissipate charge and remove artifacts. Data from these samples are being used to address two primary questions: (1) Can CCSEM technology accurately describe elemental compounds derived from dust samples and therefore derive mineral content and (2) Are African dusts created through Pedogenic or Aeolian processes. The creation of a 19-point elemental classification system was used to separate and analyze each of the 4000 data points that were taken from 85 samples. Initial findings show large amounts of Fe, Si, and Al-rich minerals. The Al-Si-rich minerals show a close correlation in relative elemental amounts. This is to be expected from clay minerals of the pyroxene group. The Fe, Si-rich minerals trend towards an inverse relationship, which is also consistent with iron oxides of the spinel group that generally consist of magnetite. Other elemental constituents within the samples include varying amounts of Ti, Ca, and K. An initial run of samples, 6 Burkina Soils and 6 Burkina Laterites, show a similarity in chemical composition, leading to the hypothesis that the Burkina Soils originated from the Burkina Laterites. As the experiment progresses we expect to see similar Aeolian processes contributing to the mineral content of other surface dusts. Further research on the effects of these wind driven dusts is needed to assess the potential health impacts and

  19. Laboratory Studies of Charging Properties of Dust Grains in Astrophysical/Planetary Environments

    NASA Astrophysics Data System (ADS)

    Tankosic, D.; Abbas, M. M.

    2012-11-01

    Dust grains immersed in ambient plasmas and radiation, are charged and coupled to the plasma through electric and magnetic fields. Dust grains in various astrophysical/planetary environments are generally charged by: (a) photoelectric emissions with incident radiation at photon energies higher than the work function of the material and (b) sticking of low energy electrons and ions of the surrounding plasma or by secondary electron emissions induced by incident electrons/ions at sufficiently high energies. Consequenly, the particle charge is an important parameter that influences physical and dynamical processes in the interplanetary and interstellar medium, planetary rings, interstellar dust clouds, comets and the outer atmospheres of planets. The charging properties of individual micron-size dust grains are expected to be substantially different from the bulk materials. However, no viable models for calculation of the charging properties of individual micron size dust grains are available at the present time. Currently, very limited experimental data are available for charging of individual micron-size dust grains. In this paper we give a review of the results of the measurements on charging of analogs of the interstellar as well as Apollo 11 and 17 lunar dust grains carried out on the Electrodynamic Balance Facility at the NASA-MSFC.

  20. Laboratory dust generation and size-dependent characterization of metal and metalloid-contaminated mine tailings deposits.

    PubMed

    Gonzales, Patricia; Felix, Omar; Alexander, Caitlin; Lutz, Eric; Ela, Wendell; Eduardo Sáez, A

    2014-09-15

    The particle size distribution of mine tailings material has a major impact on the atmospheric transport of metal and metalloid contaminants by dust. Implications to human health should be assessed through a holistic size-resolved characterization involving multidisciplinary research, which requires large uniform samples of dust that are difficult to collect using conventional atmospheric sampling instruments. To address this limitation, we designed a laboratory dust generation and fractionation system capable of producing several grams of dust from bulk materials. The equipment was utilized in the characterization of tailings deposits from the arsenic and lead-contaminated Iron King Superfund site in Dewey-Humboldt, Arizona. Results show that metal and metalloid contaminants are more concentrated in particles of < 10 μm aerodynamic diameter, which are likely to affect surrounding communities and ecosystems. In addition, we traced the transport of contaminated particles from the tailings to surrounding soils by identifying Pb and Sr isotopic signatures in soil samples. The equipment and methods developed for this assessment ensure uniform samples for further multidisciplinary studies, thus providing a tool for comprehensive representation of emission sources and associated risks of exposure.

  1. Laboratory Investigations of the Physical and Optical Properties of the Analogs of Individual Cosmic Dust Grains

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

    Microdsub-micron size cosmic dust grains play an important role in the physical and dynamical process in the galaxy, the interstellar medium, and the interplanetary and planetary environments. The dust grains in various astrophysical environments are generally charged by a variety of mechanisms that include collisional process with electrons and ions, and photoelectric emissions with UV radiation. The photoelectric emission process is believed to be the dominant process in many astrophysical environments with nearby UV sources, such as the interstellar medium, diffuse clouds, the outer regions of the dense molecular clouds, interplanetary medium, dust in planetary environments and rings, cometary tails, etc. Also, the processes and mechanisms involved in the rotation and alignment of interstellar dust grains are of great interest in view of the polarization of observed starlight as a probe for evaluation of the galactic magnetic field.

  2. Laboratory investigation of electric charging of dust particles by electrons, ions, and UV radiation

    NASA Technical Reports Server (NTRS)

    Svestka, Jiri; Pinter, S.; Gruen, E.

    1989-01-01

    In many cosmic environments electric charging of dust particles occurs by electrons, ions, and UV radiation. In case of interstellar dust particles the value of their electric charge can have, for instance, very important consequences for their destruction rate in supernova remnant's shock waves and can globally influence the overall life cycle of dust particles in galaxies. For experimental simulation of charging processes a vacuum chamber was used in which the particles fall through an electron or ion beam of energies up to 10 KeV. The aim of the experiments was to attain maximum charge of dust particles. Furthermore the influence of the rest gas was also determined because electrons and ions produced by collisional ionization of the rest gas can result in significant effects. For measurement particles from 1 to 100 microns from glass, carbon, Al, Fe, MgO, and very loosely bound conglomerates of Al2O3 were used.

  3. Engineering Water Analysis Laboratory Activity.

    ERIC Educational Resources Information Center

    Schlenker, Richard M.

    The purposes of water treatment in a marine steam power plant are to prevent damage to boilers, steam-operated equipment, and steam and condensate lives, and to keep all equipment operating at the highest level of efficiency. This laboratory exercise is designed to provide students with experiences in making accurate boiler water tests and to…

  4. Laboratory Experiments with the Concordia College High-Speed Dust Particle Accelerator

    NASA Astrophysics Data System (ADS)

    Manning, H. L.

    2011-12-01

    During the Apollo Era, NASA's Goddard Space Flight Center built a 2MeV high-speed, dust particle accelerator. This facility was used to test and calibrate the LEAM instrument which was flown to the lunar surface by Apollo 17. As the Apollo project wound down, NASA no longer had need of the dust particle accelerator, and in 1975, it was move to Concordia College in Moorhead, MN. Through the years, it has been maintained and some modifications and improvements have been made to it. In the past decade, the facility has been revived and used by several collaborating institutions to study dust detector instrumentation as well as the effects of dust impacts on various materials. We have tested a prototype, space-flight dust particle detector. Also, piezoelectric pins which can be used as dust detectors were studied to learn the pin's response to single particle impacts of different energies and momenta, and then those measured responses were compared with theoretical models. The effects of high speed impacts on ultra-high temperature ceramics, aerogel, and several different thin films have also been studied at our facility. The results of these experiments will be presented.

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

    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 Saharan region. A continuous flow diffusion chamber was operated to measure the ice nucleation ability of the dust particles in the temperature range of relevance to cirrus and mixed-phase clouds (-65dust nucleated ice heterogeneously in the deposition mode colder than about -40 °C, but required droplet activation in the exclusively heterogeneous ice nucleation regime warmer than -36 °C. Ice nucleated on 1% of dry generated dust particles of a given type at a similar relative humidity with respect to ice irrespective of temperature between -60 and -40 °C, however differences in relative humidity for ice nucleation was observed between the different dust types. The Saharan dust types exhibited a dependency on particle size below 500 nm. Additional data were collected during the International Workshop on Comparing Ice Nucleation Measurement Systems (ICIS, 2007) which indicated that ice nucleation on larger, polydisperse dust particles occurs at warmer temperatures than found for the smaller particles. When particles were coated with secondary organic aerosol (SOA) species, higher relative humidity was required for ice nucleation below -40 °C, similar to that required for homogeneous nucleation of sulfates. However, ice nucleation was still

  6. A Scheme for Dust Collection and Analysis: A Student-Led Project

    NASA Astrophysics Data System (ADS)

    Brockie, I.; Kelley, M. C.; Hirzel, A.; Gumbel, J.

    2012-12-01

    Under New York Space Grant funding, we have designed a dust collector to be launched on a NASA Terrier-Orion rocket in 2014 and then recovered in the waters off Wallops Island, VA. The prime target is the meteoric dust layer near 95 km, but we will also see if dust filtering exists lower in the atmosphere from this source, using multiple collection strategies. The collector is based on aerogel, the same material used in the Stardust mission, which collected material from the comet tail. This form of glass has an extremely low specific gravity, <0.02. This material will be provided by Stephen Jones, who made the Stardust collector. Collection timing will be provided by the flight-tested Cornell COUGAR GPS system. Analysis will be done at San Diego State University (SDSU) in William Tong's laboratory. The SDSU system is a multiple laser-based unit with a sensitivity of 10-8 moles. We will also use this new technology to study some of the Stardust material that was saved for this purpose.

  7. Source Code Analysis Laboratory (SCALe)

    DTIC Science & Technology

    2012-04-01

    revenue. Among respondents to the IAAR survey, 86% of companies certified in quality management realized a positive return on investment (ROI). An...SCALe undertakes. Testing and calibration laboratories that comply with ISO /IEC 17025 also operate in accordance with ISO 9001 . • NIST National...17025:2005 accredited and ISO 9001 :2008 registered. 4.3 SAIC Accreditation and Certification Services SAIC (Science Applications International

  8. Statistical evaluation of data from multi-laboratory testing of a measurement method intended to indicate the presence of dust resulting from the collapse of the World Trade Center.

    PubMed

    Kahn, Henry D; Rosati, Jacky A; Bray, Andrew P

    2012-10-01

    In this paper we describe a statistical analysis of the inter-laboratory data summarized in Rosati et al. (2008) to assess the performance of an analytical method to detect the presence of dust from the collapse of the World Trade Center (WTC) on September 11, 2001. The focus of the inter-lab study was the measurement of the concentration of slag wool fibers in dust which was considered to be an indicator of WTC dust. Eight labs were provided with two blinded samples each of three batches of dust that varied in slag wool concentration. Analysis of the data revealed that three of labs, which did not meet measurement quality objectives set forth prior to the experimental work, were statistically distinguishable from the five labs that did meet the quality objectives. The five labs, as a group, demonstrated better measurement capability although their ability to distinguish between the batches was somewhat mixed. This work provides important insights for the planning and implementation of future studies involving examination of dust samples for physical contaminants. This work demonstrates (a) the importance of controlling the amount of dust analyzed, (b) the need to take additional replicates to improve count estimates, and (c) the need to address issues related to the execution of the analytical methodology to ensure all labs meet the measurement quality objectives.

  9. The risk analysis of dust electrostatic based on on-site survey of polypropylene plant

    NASA Astrophysics Data System (ADS)

    Wu, Xiumin; He, Mingjun; Yu, Haibo

    2013-03-01

    The dust electrostatic explosion accidents in polypropylene plant are mainly caused by the interaction of combustible gas, dust and static electricity. This paper analyses the key parts easy to produce dust and the risks of dust electrostatic by on-site survey of polypropylene plant, and proposes corresponding safety protection measures. The analysis results indicate that any careless mistakes and deviation in every step of process control may lead to electrostatic explosion in the silo. And if the equipment has some inherent defects and there are some careless mistakes in the process control, it will be easier to cause dust electrostatic explosion accidents.

  10. Amorphous Silica- and Carbon- rich nano-templated surfaces as model interstellar dust surfaces for laboratory astrochemistry

    NASA Astrophysics Data System (ADS)

    Pascual, Natalia; Dawes, Anita; González-Posada, Fernando; Thompson, Neil; Chakarov, Dinko; Mason, Nigel J.; Fraser, Helen Jane

    2015-08-01

    Experimental studies on surface astrochemistry are vital to our understanding of chemical evolution in the interstellar medium (ISM). Laboratory surface-astrochemists have recently begun to study chemical reactions on interstellar dust-grain mimics, ranging from graphite, HOPG and graphene (representative of PAHs or large C-grains in the ISM) to amorphous olivine (representative of silicate dust) and ablated meteoritic samples (representative of interplanetary dust). These pioneering experiments show that the nature of the surface fundamentally affects processes at the substrate surface, substrate-ice interface, and ice over-layer. What these experiments are still lacking is the ability to account for effects arising from the discrete nano-scale of ISM grains, which might include changes to electronic structure, optical properties and surface-kinetics in comparison to bulk materials. The question arises: to what extent are the chemical and optical properties of interstellar ices affected by the size, morphology and material of the underlying ISM dust?We have designed, fabricated and characterised a set of nano-structured surfaces, where nanoparticles, representative of ISM grains, are adhered to an underlying support substrate. Here we will show the nanoparticles that have been manufactured from fused-silica (FS), glassy carbon (GC) and amorphous-C (aC). Our optical characterisation data shows that the nanostructured surfaces have different absorption cross-sections and significant scattering in comparison to the support substrates, which has implications for the energetic processing of icy ISM dust. We have been able to study how water-ice growth differs on the nanoparticles in comparison to the “flat” substrates, indicating increased ice amorphicity when nanoparticles are present, and on C-rich surfaces, compared to Si-rich particles. These data will be discussed in the context of interstellar water-ice features.

  11. Analysis of two Saharan dust events of North Africa in the Mediterranean region by Using SKIRON/Eta model

    NASA Astrophysics Data System (ADS)

    Benaouda, D.; Kallos, G.; Azzi, A.; Louka, P.; Benlefki, A.

    2009-04-01

    As it is well known established that significant ecosystems effects can be produced by pollutants generated many hundreds of kilometres away. Desert is natural laboratories containing valuable mineral deposits that were formed in the arid environment or that were exposed by erosion. Dust is a key species of many biogeochemical. One important effect of the dust cycle is triggering of various biochemical reactions between dust ingredients and the environment. The biogeochemical impact of desert dust also remains a matter of discussion regarding its contribution for different major and minor elements to terrestrial and marine systems and especially its potential fertilising role for remote oceanic areas by supplying micronutrients such as phosphorus and iron. Saharan dust is responsible for the supply of nutrients resulting in the increase of the production of the pelagic system, but competitively may remove phosphorus, through the adsorption on dust particles, contributing to the oligotrophy of the system, in addition, the presence of Si and Fe in the dust deposition may change the phytoplankton communities resulting in fast growth rates leading to blooms. In addition to direct radiative forcing, dust participates in indirect climate forcing through its role as a cloud-condensation nucleus and potential atmospheric CO2 regulator via biospheric nutrient delivery. Scattering and absorption of radiation by dust have impacts on the Earth's radiation budget, the thermal structure of the troposphere, and actinic fluxes, altering dynamical and photochemical processes. Coating of dust particles under polluted conditions can change microphysical properties and promote surface chemical. The Mediterranean Sea is a semi-enclosed basin, which receives substances sporadically from the arid regions of the Sahara desert. In such processes, dust modifies biochemistry of the Mediterranean water, changes features of the terrestrial ecosystems, and neutralises acid rains. Mineral dust

  12. A New Population Dataset on Dust Devil Pressure Drops : Setting the Stage for Mars Science Laboratory

    NASA Astrophysics Data System (ADS)

    Lorenz, R. D.

    2012-09-01

    A quarter of a century ago in the first in-situ study of dust devils on Mars, Ryan and Lucich (1983) rue that 'Unfortunately, we have been unable to find a terrestrial data set that permits a one-to-one comparison with our Mars data'. Remarkably, this state of affairs has largely persisted. Here I present a set of fixed station terrestrial field data, enabled by recent technological developments, which enables a direct comparison with dust devils (as indicated by vortex pressure drops) from Mars Pathfinder, Phoenix, and hopefully MSL Curiosity.

  13. Multielement analysis of interplanetary dust particles using TOF-SIMS

    NASA Technical Reports Server (NTRS)

    Stephan, T.; Kloeck, W.; Jessberger, E. K.; Rulle, H.; Zehnpfenning, J.

    1993-01-01

    Sections of three stratospheric particles (U2015G1, W7029*A27, and L2005P9) were analyzed with TOF-SIMS (Time Of Flight-Secondary Ion Mass Spectrometry) continuing our efforts to investigate the element distribution in interplanetary dust particles (IDP's) with high lateral resolution (approximately 0.2 micron), to examine possible atmospheric contamination effects, and to further explore the abilities of this technique for element analysis of small samples. The samples, previously investigated with SXRF (synchrotron X-ray fluorescence analysis), are highly enriched in Br (Br/Fe: 59 x CI, 9.2 x CI, and 116 x CI, respectively). U2015G1 is the IDP with the by far highest Zn/Fe-ratio (81 x CI) ever reported in chondritic particles.

  14. Localized treatments using commercial dust and liquid formulations of fipronil against Coptotermes formosanus (Isoptera: Rhinotermitidae) in the laboratory.

    PubMed

    Gautam, Bal K; Henderson, Gregg; Wang, Cai

    2014-04-01

    Use of proper application methods and formulations of termiticides are important to reduce their negative impact to the environment. In this study, we conducted laboratory experiments to determine the effect of localized treatments with commercial dust and liquid formulations of fipronil against Formosan subterranean termites, Coptotermes formosanus Shiraki. The test arena consisted of a specially designed 16-chambered structure with a center chamber connected to 5 foraging chambers that themselves were connected to 10 additional foraging chambers. One peripheral chamber received a liquid or dust treatment and termites were released in the center chamber. Results showed that >91% of the termites were dead within the 9-d test period despite the localized treatment of only 1 foraging chamber. Termites that were still alive after 9 d were transferred to an untreated dish and held for 10 more days. The majority of those termites were dead and the rest were moribund on day 19. Regardless of the specific dish treated, both formulations of fipronil were found to be highly efficacious. Termites did not exhibit repellency to either formulation. Our results suggest that localized (or spot) treatment with either commercially available dust or liquid formulations of fipronil can be a viable option for control of a termite infestation where complete soil drenching is not desirable.

  15. Cotton dust exposure: Analysis of pulmonary function and respiratory symptoms

    PubMed Central

    Dangi, Bharat M; Bhise, Anjali R

    2017-01-01

    Background: Cotton industry workers are exposed to various hazards in the different departments of textile factories. The major health problems associated with cotton dust are respiratory problems, byssinosis, bronchitis and asthma. Objective: To study the effect of cotton dust exposure on pulmonary function and respiratory symptoms. Settings and Design: This cross-sectional observational study was conducted at cotton mill in the Ahmedabad city. Materials and Methods: One hundred cotton mill workers of the weaving and spinning area participated in this study while 100 age- and gender-matched male subjects living in the residential area served as the control group. A questionnaire was used to inquire about respiratory symptoms and spirometry was done in both the groups. Statistical Analysis Used: Student's t-test was used to find the difference between spirometric parameters, and Chi-square test was used to find the difference between respiratory symptoms. Results: Respiratory symptoms were statistically significantly more common in the cotton mill workers compared to control group. Cotton mill workers group also showed significant (P < 0.0001) decrease in forced expiratory volume in 1 s (FEV1), ratio of FEV1 and forced vital capacity (FVC) and peak expiratory flow rate, and no significant difference of FVC between groups. There was an association of duration of exposure and symptoms with spirometric abnormality. Conclusion: Cotton mill workers showed a significant decrease in spirometric parameters and increase in respiratory symptoms. As the duration of exposure and symptoms increased, spirometric abnormality increased. PMID:28360462

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

    SciTech Connect

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

    2015-08-16

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

  17. Cosmic dust

    NASA Technical Reports Server (NTRS)

    Brownlee, Donald E.; Sandford, Scott A.

    1992-01-01

    Dust is a ubiquitous component of our galaxy and the solar system. The collection and analysis of extraterrestrial dust particles is important to exobiology because it provides information about the sources of biogenically significant elements and compounds that accumulated in distant regions of the solar nebula and that were later accreted on the planets. The topics discussed include the following: general properties of interplanetary dust; the carbonaceous component of interplanetary dust particles; and the presence of an interstellar component.

  18. Polluted Dust Classification and Its Optical Properties Analysis Using CALIPSO Data and Simulation

    NASA Astrophysics Data System (ADS)

    Ding, J.; Yang, P.; Holz, R.; Vaughan, M. A.; Hu, Y.

    2015-12-01

    In CALIPSO Level 2 aerosol data, dust particles are classified into two subtypes, namely, pure dust and polluted dust based on lidar backscatter, depolarization ratio and surface types. In this research, the polluted dust subtype is found to have two distinct modes in terms of integrated depolarization ratio (IDR) and integrated total color ratio (ICR). Dust with smaller IDR and ICR occurs mainly over areas with strong smoke emissions such as industrial cities. This kind of polluted dust originating from East Asia is also found over the Pacific Ocean. In contrast, the other type originating from the Saharan desert with larger IDR and ICR occurs mainly over the Atlantic Ocean. The disparities of IDR and ICR may result from different pollutants. The polluted dust with smaller ICR and IDR should have stronger absorption of light and may contain black carbon. Other chemical compounds such as sea salts may account for polluted dust with larger ICR and IDR. To further separate the types of polluted dust, cluster analysis is applied to determine the centroid of each type in terms of IDR and ICR. Furthermore, scattering models of dust mixed with various pollutants are constructed to be included in a CALIPSO simulator. The simulated IDR and ICR values are compared with data to retrieve the chemical compositions of polluted dust. The difference of polluted dust over the Pacific and Atlantic Ocean provides new evidence about long-range transport of Asian dust to North America. The distribution of dust polluted by black carbon is determined, which can improve knowledge about the effect of black carbon on the earth's radiation budget.

  19. Laboratory and observational study of the interrelation of the carbonaceous component of interstellar dust and solar system materials

    NASA Technical Reports Server (NTRS)

    Allamandola, L. J.; Sanford, S. A.; Schutte, W. A.; Tielens, A. G. G. M.

    1991-01-01

    By studying the chemical and isotopic composition of interstellar ice and dust, one gains insight into the composition and chemical evolution of the solid bodies in the solar nebula and the nature of the material subsequently brought into the inner part of the solar system by comets and meteorites. It is now possible to spectroscopically probe the composition of interstellar ice and dust in the mid-infrared, the spectral range which is most diagnostic of fundamental molecular vibrations. We can compare these spectra of various astronomical objects (including the diffuse and dense interstellar medium, comets, and the icy outer planets and their satellites) with the spectra of analogs we produce in the laboratory under conditions which mimic those in these different objects. In this way one can determine the composition and abundances of the major constituents of the various ices and place general constraints on the types of organics coating the grains in the diffuse interstellar medium. In particular we have shown the ices in the dense clouds contain H2O, CH3OH, CO, perhaps some NH3 and H2CO, we well as nitriles and ketones or esters. Furthermore, by studying the photochemistry of these ice analogs in the laboratory, one gains insight into the chemistry which takes place in interstellar/precometary ices. Chemical and spectroscopic studies of photolyzed analogs (including deuterated species) are now underway. The results of some of these studies will be presented and implications for the evolution of the biogenic elements in interstellar dust and comets will be discussed.

  20. Climate Analysis and Long Range Forecasting of Dust Storms in Iraq

    DTIC Science & Technology

    2009-06-01

    Miller, S. D. 2007: COAMPS Real-Time Dust Storm Forecasting during Operation Iraqi Freedom. Weather and Forecasting 22:192-206. Moss, S., 2007...LONG RANGE FORECASTING OF DUST STORMS IN IRAQ by Jacquelyn Crook June 2009 Thesis Advisor: Tom Murphree Co-Advisor: Rebecca Stone...Master’s Thesis 4. TITLE AND SUBTITLE Climate Analysis and Long Range Forecasting of Dust Storms in Iraq 6. AUTHOR(S) Jacquelyn C Crook 5

  1. Windblown Dust on Mars: Laboratory Simulations of Flux as a Function of Surface Roughness

    NASA Technical Reports Server (NTRS)

    Greeley, Robert; Wilson, Gregory; Coquilla, Rachel; White, Bruce; Haberle, Robert

    2000-01-01

    Experiments were conducted to determine the flux of dust (particles less than few microns in diameter) under Martian atmospheric conditions for surface of three aerodynamic roughness (z(sub 0)). For smooth surface on Mars (z(sub 0) = 0.00125 cm corresponding to 0.0125 cm on Mars) suspension threshold was not achieved at the highest velocities run (u(sub 0) = 322 cm/s); for a moderately rough surface (z(sub 0) = 0.010 cm corresponding to 0.01 cm on Mars), flux averaged 1.5 x 10(exp -7)g/sq cm/s; for a rough surface (z(sub 0) = 0.015 cm corresponding to 0.15 cm on Mars), flux averaged 5 x 10(exp -7) g/sq cm/s. Although the results are preliminary, flux varied widely as a function of wind speed and roughness, suggesting that raising dust into suspension on Mars is complex. Nonetheless, using these results as a guide, 9000 Mt of dust could be raised into the atmosphere of Mars per second from only 5% of the surface.

  2. Protoplanetary Dust

    NASA Astrophysics Data System (ADS)

    Apai, D.´niel; Lauretta, Dante S.

    2014-02-01

    Preface; 1. Planet formation and protoplanetary dust Daniel Apai and Dante Lauretta; 2. The origins of protoplanetary dust and the formation of accretion disks Hans-Peter Gail and Peter Hope; 3. Evolution of protoplanetary disk structures Fred Ciesla and Cornelius P. Dullemond; 4. Chemical and isotopic evolution of the solar nebula and protoplanetary disks Dmitry Semenov, Subrata Chakraborty and Mark Thiemens; 5. Laboratory studies of simple dust analogs in astrophysical environments John R. Brucato and Joseph A. Nuth III; 6. Dust composition in protoplanetaty dust Michiel Min and George Flynn; 7. Dust particle size evolution Klaus M. Pontoppidan and Adrian J. Brearly; 8. Thermal processing in protoplanetary nebulae Daniel Apai, Harold C. Connolly Jr. and Dante S. Lauretta; 9. The clearing of protoplanetary disks and of the protosolar nebula Ilaira Pascucci and Shogo Tachibana; 10. Accretion of planetesimals and the formation of rocky planets John E. Chambers, David O'Brien and Andrew M. Davis; Appendixes; Glossary; Index.

  3. Instruments for the Analysis of the Martian Dust Aerosol

    NASA Astrophysics Data System (ADS)

    Merrison, J. P.; Gunnlaugsson, H. P.; Jensen, J.; Kinch, K.; Nørnberg, P.; Rasmussen, K. R.

    2004-04-01

    Dust is a dominant component in the Martian environment, featuring significantly in the atmosphere and covering most of the planets surface. The origin of this dust is of great scientific interest in the study of the Martian climate and its history. It also poses a serious hazard to both instrumentation and biological systems alike. Accurate measurements of the physical nature of the dust, the local wind flow and dust concentration are necessary for modelling the transport of this dust. Using a unique re-circulating Mars simulation wind tunnel a series of miniaturised instruments are being developed which would allow direct, in-situ measurements of a wide variety of physical properties of the Martian aerosol. Specifically three prototype instruments have been constructed and successfully tested, these were a miniature laser anemometer, which determines velocity and suspended dust concentration, an optoelectronics device for quantification of dust deposition and an instrument which collects electrically charged wind-blown dust. These instruments will be presented and the possibility for integration discussed.

  4. Laboratory and Field Evaluation of Dust Abatement Products for Expedient Helipads

    DTIC Science & Technology

    2010-09-01

    generated by an electric fan motor and transmitted through a 3-in. polyvinyl chloride pipe with a rectangular aperture 4.5 in. wide and 0.5 in. tall...will be used to update the USMC Dust Abatement Handbook (PCN 50011240000). DISCLAIMER: The contents of this report are not to be used for...palliatives investigated in this study. TerraLOC® TerraLOC ® is a polyvinyl alcohol solution made by MonoSol, LLC. TerraLOC® is water soluble and

  5. The sensitivity of new laboratory-based heterogeneous freezing schemes for dust and biological particles to time and temperature

    NASA Astrophysics Data System (ADS)

    Niedermeier, D.; Ervens, B.; Hartmann, S.; Wex, H.; Stratmann, F.

    2012-12-01

    Heterogeneous ice nucleation has been recently described by means of the Soccer ball model that takes into account multiple nucleation sites on individual particles [Niedermeier et al., 2011]. In order to study sensitivities of the implied contact angle distributions, a modified version of the Soccer ball model is implemented into a parcel model that describes in detail heterogeneous ice formation and ice /liquid water partitioning [Ervens and Feingold, 2012]. Soccer ball model parameters (number of surface sites, mean and width of the contact angle distribution) are determined from immersion freezing measurements of mineral dust particles and bacteria performed with the Leipzig Aerosol Cloud Interaction Simulator [LACIS, Hartmann et al., 2011]. While biological particles (e.g., bacteria) are much less frequent in the atmosphere, they can induce droplet freezing already at about -5°C as opposed to dust that shows efficient freezing only at lower temperatures (below -15°C). We will identify updraft regimes, temperature and IN concentration ranges where dust or biological particles, respectively, might dominate the number concentration of frozen droplets in mixed phase clouds. Additional model studies will focus on the importance of time versus temperature dependence and explore the usefulness of alternative descriptions of the freezing behavior that can be derived based on the respective laboratory studies using LACIS. These descriptions include the choice of a single contact angle as opposed to contact angle distributions or time-independent expressions. These results reveal that under selected conditions, it might be a satisfactory approximation to assume singular freezing behavior. Our sensitivity studies will help to refine time-independent freezing parameterizations using laboratory data and help bridging the current divergence between deterministic approaches [e.g., Hoose and Möhler, 2012] and physically-based approaches (classical nucleation theory) that

  6. Dust devils in the laboratory: Effect of surface roughness on vortex dynamics

    NASA Astrophysics Data System (ADS)

    Neakrase, Lynn D. V.; Greeley, Ronald

    2010-05-01

    Experiments simulating vortex interactions with rough surfaces were conducted at Earth ambient and Mars analog atmospheric conditions. Pressure profiles were obtained to assess the effect of nonerodible roughness elements on vortex structure at the surface. As roughness increased, vortex size increased and tangential velocity decreased. Particle threshold experimental results suggested that small increases in surface roughness enabled reduced threshold velocities to lift fine particles (<100μm) from the surface. This “optimal roughness” or the amount of roughness necessary for enhancing sediment transport from the surface, could allow weaker dust devils to lift more material from the surface than otherwise possible. Sediment flux was calculated for different sediment sizes and densities to determine how surface roughness affects the lifting potential by dust devils. Sediment fluxes were similar to previous studies with bulk averages ranging from 10-5 to 1 kg m-2 s-1, but they could be subdivided based on roughness. The results showed that for the low roughness case (λ ≈ 0.03), fluxes were at a maximum ranging from 10-3 to 1 kg m-2 s-1 compared to two rougher surfaces (λ ≈ 0.11 and 0.23). For the lowest roughness density the airflow around the elements is enhanced, whereas the higher roughness values showed more loss of energy to the surface, impeding sediment transport similar to boundary layer studies examining roughness effects on sediment transport.

  7. Laboratory theory and methods for sediment analysis

    USGS Publications Warehouse

    Guy, Harold P.

    1969-01-01

    The diverse character of fluvial sediments makes the choice of laboratory analysis somewhat arbitrary and the pressing of sediment samples difficult. This report presents some theories and methods used by the Water Resources Division for analysis of fluvial sediments to determine the concentration of suspended-sediment samples and the particle-size distribution of both suspended-sediment and bed-material samples. Other analyses related to these determinations may include particle shape, mineral content, and specific gravity, the organic matter and dissolved solids of samples, and the specific weight of soils. The merits and techniques of both the evaporation and filtration methods for concentration analysis are discussed. Methods used for particle-size analysis of suspended-sediment samples may include the sieve pipet, the VA tube-pipet, or the BW tube-VA tube depending on the equipment available, the concentration and approximate size of sediment in the sample, and the settling medium used. The choice of method for most bed-material samples is usually limited to procedures suitable for sand or to some type of visual analysis for large sizes. Several tested forms are presented to help insure a well-ordered system in the laboratory to handle the samples, to help determine the kind of analysis required for each, to conduct the required processes, and to assist in the required computations. Use of the manual should further 'standardize' methods of fluvial sediment analysis among the many laboratories and thereby help to achieve uniformity and precision of the data.

  8. Understanding dust emission in the Bodélé region by extracting locally mobilized dust aerosols from satellite Aerosol Optical Depth data using principal component analysis

    NASA Astrophysics Data System (ADS)

    Parajuli, Sagar Prasad; Yang, Zong-Liang

    2017-02-01

    Despite the increasing availability of satellite and ground-based Aerosol Optical Depth (AOD) data, their application in dust modeling is limited because these data do not differentiate locally mobilized dust from remotely advected dust and other aerosols. In this work, we extract the locally mobilized Dust Optical Depth (DOD) in the Bodélé region from historical AOD data through a principal component analysis of wind speed and AOD time series (2003-2012). Principal component analysis effectively identifies the correlated signature between wind speed and AOD making it possible to separate the dust component from AOD data. Using the reconstructed DOD, we then study the effect of key environmental variables, namely wind speed, soil moisture, soil temperature, vegetation, and boundary layer height on dust emission. Results show that all of these environmental variables are significantly correlated with the reconstructed DOD indicating their association with the dust emission process. The extraction technique described in this study can be extended to regional and global scales to identify the dust sources which are not adequately represented in regional and global dust models.

  9. An Analysis of the Laboratory Assisting Occupation.

    ERIC Educational Resources Information Center

    McGee, Patricia; And Others

    The general purpose of the occupational analysis is to provide workable, basic information dealing with the many and varied duties performed in the laboratory assistant occupation. The document opens with a brief introduction followed by a job description. The bulk of the document is presented in table form. Eleven duties are broken down into a…

  10. 7 CFR 160.17 - Laboratory analysis.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Laboratory analysis. 160.17 Section 160.17 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) NAVAL STORES REGULATIONS...

  11. Biomass Compositional Analysis Laboratory (Fact Sheet)

    SciTech Connect

    Not Available

    2014-07-01

    At the Biomass Compositional Analysis Laboratory, NREL scientists have more than 20 years of experience supporting the biomass conversion industry. They develop, refine, and validate analytical methods to determine the chemical composition of biomass samples before, during, and after conversion processing. These high-quality compositional analysis data are used to determine feedstock compositions as well as mass balances and product yields from conversion processes.

  12. Dust Impact Monitor DIM onboard Rosetta/Philae: Laboratory Calibration with Impact Experiments

    NASA Astrophysics Data System (ADS)

    Krüger, H.; Ossowski, T.; Seidensticker, K.; Apathy, I.; Fischer, H.-H.; Hirn, A.; Jünemann, M.; Loose, A.; Peter, A.; Sperl, M.

    2011-10-01

    The Rosetta lander spacecraft Philae, which will land on the surface of comet 67P/Churyumov- Gerasimenko in late 2014, is equipped with the Dust Impact Monitor instrument (DIM). The DIM sensor, which is part of the SESAME instrument package [Seidensticker et al., 2007], consists of three piezoelectric detectors, each one mounted on the outer side of a cube facing in three orthogonal directions. The total sensor area is approximately 70 cm2. DIM will measure impacts of sub-millimeter and millimeter sized ice and dust particles that are emitted from the nucleus and transported into the cometary coma by the escaping gas flow. A grain-size dependent fraction of the emitted grains is expected to fall back to the nucleus surface due to gravity. DIM will be able to detect both these components, the backfalling particles as well as the grains hitting the detector on direct trajectories from the surface. With DIM we will be able to measure fluxes, impact directions as well as the speed and size of the impacting cometary particles. Two particle acceleration devices for impact calibration experiments are presently available at Max- Planck-Institut für Sonnensystemforschung (MPS), Katlenburg-Lindau: With (a) a dedicated dropping device and (b) a small air gun we can simulate impacts with particles of different materials (steel, glass, ruby, polyethylen, etc.), radii between 0.2 and 1mm and impact speeds up to 2msec-1. We have performed a large number of impact experiments with two flight spare units of the DIM sensor at MPS. We present the results from our impact experiments and discuss their implications for the calibration of the DIM flight instrument.

  13. Laboratory comparison of vacuum, OSHA, and HUD sampling methods for lead in household dust.

    PubMed

    Reynolds, S J; Etre, L; Thorne, P S; Whitten, P; Selim, M; Popendorf, W J

    1997-06-01

    The goals of this project were to evaluate and compare the efficiency and reproducibility of three methods for sampling lead-containing dust in homes. Lead-containing dust was generated in a 1-m3 chamber and uniformly deposited onto surfaces typically found in the home (painted wood, unpainted wood, varnished wood, linoleum, and carpet). Trials with three levels of lead concentrations were performed for each surface. Replicate, side-by-side, surface samples were collected using the Occupational Safety and Health Administration (OSHA) wipe method, the Department of Housing and Urban Development (HUD) wipe method, and a vacuum-filter method. Samples were digested with nitric acid and analyzed using graphite furnace atomic absorption spectroscopy per National Institute of Occupational Safety and Health Method 7105. Recovery for the HUD method was consistently the highest on most surfaces (linoleum, 89.9 to 108.9%; painted wood, 71.2 to 153.7%; unpainted wood, 25.3 to 76.0%; varnished wood, 8.7 to 165.6%). On carpet the vacuum method had a significantly higher recovery (26.2 to 47.8%). For all sampling methods the percent recovery depended on type of surface and lead concentration. The reproducibility of percent recovery for the HUD (pooled coefficient of variation [CV] = 0.22) and OSHA (pooled CV = 0.27) methods was lower than that of the vacuum method (pooled CV = 0.46), though not statistically significant. Reproducibility for all methods did not vary significantly over surface type or lead concentration. Overall, the HUD method yielded the most accurate measurements, with recoveries closest to 100%. It was also more durable than the OSHA method, where Whatman filters were observed to tear.

  14. An analysis of the history of dust activity on Mars

    NASA Astrophysics Data System (ADS)

    Martin, L. J.; Zurek, R. W.

    1993-02-01

    A comprehensive list of dust storm activity on Mars has been compiled from various published lists and additional data. For uniformity and clarity, each event is classified using a new system that includes a well-defined nomenclature. Maps showing the reported locations of events have been compiled. Detailed commentaries describe the events and/or circumstances of their observation. The seasonal distribution of Martian dust events is diagrammed and discussed together with a seasonal and annual (Mars years) timeline that includes the frequency of photographic coverage. Regional dust storms tend to occur most frequently, and all planet-encircling dust storms have been observed during the southern spring and summer seasons, although there is significant interannual variability.

  15. Laboratory studies of reactions of atmospheric gases with components of mineral dust aerosol and research in chemical education

    NASA Astrophysics Data System (ADS)

    Schuttlefield, Jennifer Dianne

    Mineral dust aerosol surfaces provide a medium in the atmosphere for heterogeneous chemistry to occur, which can alter the chemical balance of the Earth's atmosphere. It is becoming increasingly clear that the heterogeneous chemistry of these aerosols is a function of relative humidity (RH), as water on the surface of these particles can enhance or inhibit reactivity depending on the reaction. In this thesis, the uptake of water on clays and oxides was investigated, as well as phase transitions for atmospherically relevant salts. Reactions of carbon dioxide and nitric acid on oxide particles in the presence and absence of water were also examined. Following the reaction of HNO 3 on an alumina surface, photoirradiation experiments were preformed to determine the effect of irradiation on the adsorbed nitrate. The results presented in this thesis provide insight into the heterogeneous reactivity of mineral dust aerosol in the presence and absence of co-adsorbed water, as well as a fundamental understanding of water uptake on soluble and insoluble aerosols. A new method, using a quartz crystal microbalance, was developed to attempt to obtain a better fundamental understanding of different mineral dust components. In addition to the laboratory research, research in chemical education is also presented in this thesis. Two different types of work being done in the area of chemical education are shown. First a new experiment was implemented into an undergraduate physical chemistry course. The technique, ATR-FTIR spectroscopy, was chosen for its ability to expose students to a technique that is commonly used in laboratory research as well as the ease for which high quality results can be obtained. Students used ATR-FTIR spectroscopy to monitor sulfate, SO 42-, adsorption on TiO2 thin films. Second, the role of cognitive load and problem difficulty was accessed with data acquired while students completed an introductory-level chemistry word problem using a web-based tool

  16. Mars Environmental Chamber for Dynamic Dust Deposition and Statics Analysis

    NASA Technical Reports Server (NTRS)

    Moeller, L. E.; Tuller, M.; Islam, M. R.; Baker, L.; Kuhlman, K.

    2004-01-01

    Recent observations of the 2001 dust storms encircling Mars confirm predictions of environmental challenges for exploration. Martian dust has been found to completely mantle the Martian surface over thousands of square kilometers and the opacity of airborne dust has been shown to be capable of modifying atmospheric temperature, radiative transfer and albedo. Planetary dust cycling dynamics are suggested to be a key factor in the evolution of the Martian surface. Long-term robotic and manned exploration of Mars will be confronted by dust deposition in periods of atmospheric calm and violent wind storms. Aeolian dust deposition recorded during the Mars Pathfinder mission was estimated to fall at rates of 20-45 microns per Earth year. Although many tools of exploration will be challenged by coating, adhesion, abrasion and possible chemical reaction of deposited, wind blown and actively disturbed Martian dust, solar cells are thought to be of primary concern. Recent modeling work of power output by gallium arsenide/germanium solar cells was validated by the Pathfinder Lander data and showed power output decreases of 0.1 to 0.5% per Martian day. A major determinant for the optimal positioning angle of solar panels employed in future missions is the angle of repose of the settling dust particles that is dependent on a variety of physical and chemical properties of the particles, the panel surface, and the environmental conditions on the Mars surface. While the effects of many of these factors are well understood qualitatively, quantitative analyses, especially under physical and chemical conditions prevailing on the Mars surface are lacking.

  17. Preliminary analysis of graphite dust releasing behavior in accident for HTR

    SciTech Connect

    Peng, W.; Yang, X. Y.; Yu, S. Y.; Wang, J.

    2012-07-01

    The behavior of the graphite dust is important to the safety of High Temperature Gas-cooled Reactors. This study investigated the flow of graphite dust in helium mainstream. The analysis of the stresses acting on the graphite dust indicated that gas drag played the absolute leading role. Based on the understanding of the importance of gas drag, an experimental system is set up for the research of dust releasing behavior in accident. Air driven by centrifugal fan is used as the working fluid instead of helium because helium is expensive, easy to leak which make it difficult to seal. The graphite particles, with the size distribution same as in HTR, are added to the experiment loop. The graphite dust releasing behavior at the loss-of-coolant accident will be investigated by a sonic nozzle. (authors)

  18. Advanced In-Situ Detection and Chemical Analysis of Interstellar Dust Particles

    NASA Astrophysics Data System (ADS)

    Sternovsky, Z.; Gemer, A.; Gruen, E.; Horanyi, M.; Kempf, S.; Maute, K.; Postberg, F.; Srama, R.; Williams, E.; O'brien, L.; Rocha, J. R. R.

    2015-12-01

    The Ulysses dust detector discovered that interstellar dust particles pass through the solar system. The Hyperdsut instrument is developed for the in-situ detection and analysis of these particles to determine the elemental, chemical and isotopic compositions. Hyperdust builds on the heritage of previous successful instruments, e.g. the Cosmic Dust Analyzer (CDA) on Cassini. Hyperdust combines a highly sensitive Dust Trajectory Sensor (DTS) and the high mass resolution Chemical Analyzer (CA). The DTS will detect dust particles as small as 0.3 μm in radius, and the velocity vector information is used to confirm the interstellar origin and/or reveal the dynamics from the interactions within the solar system. The effective target area of the CA is > 600 cm2 achieves mass resolution in excess of 200, which is considerably higher than that of CDA, and is acheved by advanced ion optics design. The Hyperdust instrument is in the final phases of development to TRL 6.

  19. Video analysis of dust events in full-tungsten ASDEX Upgrade

    NASA Astrophysics Data System (ADS)

    Brochard, F.; Shalpegin, A.; Bardin, S.; Lunt, T.; Rohde, V.; Briançon, J. L.; Pautasso, G.; Vorpahl, C.; Neu, R.; The ASDEX Upgrade Team

    2017-03-01

    Fast video data recorded during seven consecutive operation campaigns (2008-2012) in full-tungsten ASDEX Upgrade have been analyzed with an algorithm developed to automatically detect and track dust particles. A total of 2425 discharges have been analyzed, corresponding to 12 204 s of plasma operation. The analysis aimed at precisely identifying and sorting the discharge conditions responsible of the dust generation or remobilization. Dust rates are found to be significantly lower than in tokamaks with carbon PFCs. Significant dust events occur mostly during off-normal plasma phases such as disruptions and particularly those preceded by vertical displacement events (VDEs). Dust rates are also increased but to a lower extent during type-I ELMy H-modes. The influences of disruption energy, heating scenario, vessel venting and vessel vibrations are also presented.

  20. Workshop on Thermal Emission Spectroscopy and Analysis of Dust, Disk, and Regoliths

    NASA Technical Reports Server (NTRS)

    Sprague, Ann L. (Editor); Lynch, David K. (Editor); Sitko, Michael (Editor)

    1999-01-01

    This volume contains abstracts that have been accepted for presentation at the workshop on Thermal Emission Spectroscopy and analysis of Dust, Disks and Regoliths, held April 28-30, 1999, in Houston Texas.

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

    PubMed

    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.

  2. Association between Occupational Exposure to Wood Dust and Cancer: A Systematic Review and Meta-Analysis

    PubMed Central

    Alonso-Sardón, Montserrat; Chamorro, Antonio-J.; Hernández-García, Ignacio; Iglesias-de-Sena, Helena; Martín-Rodero, Helena; Herrera, Cristian; Marcos, Miguel; Mirón-Canelo, José Antonio

    2015-01-01

    Objective To perform a systematic review to analyze the association between occupational exposure to wood dust and cancer. Methods A systematic literature search of entries made in the MEDLINE-PubMed database between 1957 and 2013 was conducted to identify studies that had assessed the relationship between occupational exposure to wood dust and different types of cancer. A meta-analysis of selected case-control and cohort studies was subsequently performed. Results A total of 114 studies were identified and 70 were selected for review. Of these, 42 studies focused on the relationship between wood dust and nasal cancer (n = 22), lung cancer (n = 11), and other types of cancer (n = 9). Low-to-moderate quality evidence that wood dust acts as a carcinogen was obtained, and a stronger association between wood dust and nasal adenocarcinoma was observed. A lesser association between wood dust exposure and lung cancer was also observed. Several studies suggested that there is a relationship between wood dust and the onset of other cancers, although there was no evidence to establish an association. A meta-analysis that included four case-controls studies showed that workers exposed to wood dust exhibited higher rates of nasal adenocarcinoma than other workers (odds ratio = 10.28; 95% confidence interval: 5.92 and 17.85; P<0,0001), although a large degree of heterogeneity was found. Conclusions Low-to-moderate quality evidence supports a causal association between cancer and occupational exposure to wood dust, and this association was stronger for nasal adenocarcinoma than for lung cancer. There was no evidence of an association between wood dust exposure and the other cancers examined. PMID:26191795

  3. Wood dust exposure and lung cancer risk: a meta-analysis.

    PubMed

    Hancock, David G; Langley, Mary E; Chia, Kwan Leung; Woodman, Richard J; Shanahan, E Michael

    2015-12-01

    Occupational lung cancers represent a major health burden due to their increasing prevalence and poor long-term outcomes. While wood dust is a confirmed human carcinogen, its association with lung cancer remains unclear due to inconsistent findings in the literature. We aimed to clarify this association using meta-analysis. We performed a search of 10 databases to identify studies published until June 2014. We assessed the lung cancer risk associated with wood dust exposure as the primary outcome and with wood dust-related occupations as a secondary outcome. Random-effects models were used to pool summary risk estimates. 85 publications were included in the meta-analysis. A significantly increased risk for developing lung cancer was observed among studies that directly assessed wood dust exposure (RR 1.21, 95% CI 1.05 to 1.39, n=33) and that assessed wood dust-related occupations (RR 1.15, 95% CI 1.07 to 1.23, n=59). In contrast, a reduced risk for lung cancer was observed among wood dust (RR 0.63, 95% CI 0.39 to 0.99, n=5) and occupation (RR 0.96, 95% CI 0.95 to 0.98, n=1) studies originating in Nordic countries, where softwood dust is the primary exposure. These results were independent of the presence of adjustment for smoking and exposure classification methods. Only minor differences in risk between the histological subtypes were identified. This meta-analysis provides strong evidence for an association between wood dust and lung cancer, which is critically influenced by the geographic region of the study. The reasons for this region-specific effect estimates remain to be clarified, but may suggest a differential effect for hardwood and softwood dusts.

  4. The dust mass in Cassiopeia A from a spatially resolved Herschel analysis

    NASA Astrophysics Data System (ADS)

    De Looze, I.; Barlow, M. J.; Swinyard, B. M.; Rho, J.; Gomez, H. L.; Matsuura, M.; Wesson, R.

    2017-03-01

    Theoretical models predict that core-collapse supernovae (CCSNe) can be efficient dust producers (0.1-1.0 M⊙), potentially accounting for most of the dust production in the early Universe. Observational evidence for this dust production efficiency is however currently limited to only a few CCSN remnants (e.g. SN 1987A, Crab nebula). In this paper, we revisit the dust mass produced in Cassiopeia A (Cas A), a ∼330-yr old O-rich Galactic supernova remnant (SNR) embedded in a dense interstellar foreground and background. We present the first spatially resolved analysis of Cas A based on Spitzer and Herschel infrared and submillimetre data at a common resolution of ∼0.6 arcmin for this 5 arcmin diameter remnant following a careful removal of contaminating line emission and synchrotron radiation. We fit the dust continuum from 17 to 500 μm with a four-component interstellar medium and supernova (SN) dust model. We find a concentration of cold dust in the unshocked ejecta of Cas A and derive a mass of 0.3-0.5 M⊙ of silicate grains freshly produced in the SNR, with a lower limit of ≥0.1-0.2 M⊙. For a mixture of 50 per cent of silicate-type grains and 50 per cent of carbonaceous grains, we derive a total SN dust mass between 0.4 and 0.6 M⊙. These dust mass estimates are higher than from most previous studies of Cas A and support the scenario of SN-dominated dust production at high redshifts. We furthermore derive an interstellar extinction map for the field around Cas A which towards Cas A gives average values of AV = 6-8 mag, up to a maximum of AV = 15 mag.

  5. Rosetta/COSIMA: High Resolution In-Situ Dust Analysis at Comet 67P/Churyumov-Gerasimenkov

    NASA Astrophysics Data System (ADS)

    Krueger, Harald; Engrand, C.; Fischer, H.; Hilchenbach, M.; Hornung, K.; Kissel, J.; Stephan, T.; Thirkell, L.; Trieloff, M.; Thomas, R.; Tubiana, C.; Varmuza, K.

    2006-09-01

    The COmetary Secondary Ion Mass Analyser (COSIMA) instrument on board ESA's Rosetta spacecraft is a high-resolution time-of-flight mass spectrometer dedicated to the in-situ analysis of cometary dust. Rosetta was launched in 2004 and will reach comet 67P/Churyumov-Gerasimenkov in 2014. The COSIMA instrument will collect cometary dust on metal targets and identify grains with sizes 10 micron and bigger with an optical camera. Material from the grain surface is sputtered with an indium ion beam and the generated secondary ions are accelerated in an electric field. Time-of-flight secondary ion mass spectra are obtained with a mass resolution of approximately 2000 at m = 100 amu. The goal of the COSIMA investigation is the in-situ characterisation of the elemental, molecular, mineralogic, and isotopic composition of dust in the coma of comet 67P/C-G. To reach this goal, we perform an extensive laboratory measurement program with a COSIMA reference instrument (RM), a twin of the flight instrument, located at Max-Planck-Institut fuer Sonnensystemforschung (MPS). Cometary dust analogues are prepared from natural and synthetic minerals (pyroxene, olivine, hydrous silicates, sulfides, etc.) with known composition and, which are believed to exist in comets. Reference spectra of these samples are obtained with the COSIMA RM instrument and with laboratory time-of-flight secondary ion mass spectrometer (TOF-SIMS) instruments located at the University of Muenster/Germany and the Laboratoire de Physique & Chimie de L'Environment in Orleans/France. We will present first results on the calibration of the COSIMA RM instrument and the identification of the elemental and mineralogic composition of reference samples.

  6. Sandia National Laboratories analysis code data base

    SciTech Connect

    Peterson, C.W.

    1994-11-01

    Sandia National Laboratories, mission is to solve important problems in the areas of national defense, energy security, environmental integrity, and industrial technology. The Laboratories` strategy for accomplishing this mission is to conduct research to provide an understanding of the important physical phenomena underlying any problem, and then to construct validated computational models of the phenomena which can be used as tools to solve the problem. In the course of implementing this strategy, Sandia`s technical staff has produced a wide variety of numerical problem-solving tools which they use regularly in the design, analysis, performance prediction, and optimization of Sandia components, systems and manufacturing processes. This report provides the relevant technical and accessibility data on the numerical codes used at Sandia, including information on the technical competency or capability area that each code addresses, code ``ownership`` and release status, and references describing the physical models and numerical implementation.

  7. Increase in dust storm related PM10 concentrations: A time series analysis of 2001-2015.

    PubMed

    Krasnov, Helena; Katra, Itzhak; Friger, Michael

    2016-06-01

    Over the last decades, changes in dust storms characteristics have been observed in different parts of the world. The changing frequency of dust storms in the southeastern Mediterranean has led to growing concern regarding atmospheric PM10 levels. A classic time series additive model was used in order to describe and evaluate the changes in PM10 concentrations during dust storm days in different cities in Israel, which is located at the margins of the global dust belt. The analysis revealed variations in the number of dust events and PM10 concentrations during 2001-2015. A significant increase in PM10 concentrations was identified since 2009 in the arid city of Beer Sheva, southern Israel. Average PM10 concentrations during dust days before 2009 were 406, 312, and 364 μg m(-3) (median 337, 269,302) for Beer Sheva, Rehovot (central Israel) and Modi'in (eastern Israel), respectively. After 2009 the average concentrations in these cities during dust storms were 536, 466, and 428 μg m(-3) (median 382, 335, 338), respectively. Regression analysis revealed associations between PM10 variations and seasonality, wind speed, as well as relative humidity. The trends and periodicity are stronger in the southern part of Israel, where higher PM10 concentrations are found. Since 2009 dust events became more extreme with much higher daily and hourly levels. The findings demonstrate that in the arid area variations of dust storms can be quantified easier through PM10 levels over a relatively short time scale of several years.

  8. What can we learn about protoplanetary disks from analysis of mid-infrared carbonaceous dust emission?

    NASA Astrophysics Data System (ADS)

    Berné, O.; Joblin, C.; Fuente, A.; Ménard, F.

    2009-03-01

    Context: The disks of gas and dust that form around young stars and can lead to planet formation contain polycyclic aromatic hydrocarbons (PAHs) and very small grains (VSGs). Aims: In this paper we analyze the mid-infrared (mid-IR) emission of these very small dust particles in a sample of 12 protoplanetary disks. Our goal is twofold: first we want to characterize the properties of these particles in disks and see how they are connected to interstellar matter, and second we investigate the possibility that their emission can be used as a probe of the physical conditions and evolution of the disk. Methods: We define a basis made of three mid-IR template spectra: PAH^0, PAH^+, and VSGs that were derived from the analysis of reflection nebulae, and an additional PAHx spectrum that was introduced recently for analysis of the spectra of planetary nebulae. Results: From the optimization of the fit of 12 star+disk spectra, using a linear combination of the 4 template spectra, we found that an additional small grain component with a broad feature at 8.3 μm is needed. We find that the fraction of VSG emission in disks decreases with increasing stellar temperature. VSGs appear to be destroyed by UV photons at the surface of disks, thus releasing free PAH molecules, which are eventually ionized as observed in photodissociation regions. In contrast, we observe that the fraction of PAHx increases with increasing star temperature except in the case of B stars where they are absent. We argue that this is compatible with the identification of PAHx as large ionized PAHs, most likely emitting in regions of the disk that are close to the star. Finally, we provide a UV-dependent scheme to explain the evolution of PAHs and VSGs in protoplanetary disks. These results allow us to put new constraints on the properties of two sources: IRS 48 and “Gomez's Hamburger” which are poorly characterized. Conclusions: Very small dust particles incorporated into protoplanetary disks are

  9. Analysis of Designs of Space Laboratories

    NASA Technical Reports Server (NTRS)

    Cohen, Marc M.

    2003-01-01

    A report presents a review of the development of laboratories in outer space, starting from the pioneering Skylab and Salyut stations of the United States and the former Soviet Union and progressing through current and anticipated future developments. The report includes textual discussions of space station designs, illustrated with drawings, photographs, and tables. The approach taken in the review was not to provide a comprehensive catalog of each space laboratory and every design topic that applies to it, but, rather, to illustrate architectural precedents by providing examples that illustrate major design problems and principles to be applied in solving them. Hence, the report deemphasizes information from the most recent space-station literature and concentrates on information from original design reports that show how designs originated and evolved. The most important contribution of the review was the development of a methodology, called "units of analysis," for identifying and analyzing design issues from the perspectives of four broad domains: laboratory science, crew, modes of operations, and the system as a whole.

  10. Network Analysis of Social Interactions in Laboratories

    NASA Astrophysics Data System (ADS)

    Warren, Aaron R.

    2008-10-01

    An ongoing study of the structure, function, and evolution of individual activity within lab groups is introduced. This study makes extensive use of techniques from social network analysis. These techniques allow rigorous quantification and hypothesis-testing of the interactions inherent in social groups and the impact of intrinsic characteristics of individuals on their social interactions. As these techniques are novel within the physics education research community, an overview of their meaning and application is given. We then present preliminary results from videotaped laboratory groups involving mixed populations of traditional and non-traditional students in an introductory algebra-based physics course.

  11. Formation and behaviour of dust particle clouds in a radio-frequency discharge: results in the laboratory and under microgravity conditions

    NASA Astrophysics Data System (ADS)

    Mikikian, M.; Boufendi, L.; Bouchoule, A.; Thomas, H. M.; Morfill, G. E.; Nefedov, A. P.; Fortov, V. E.; PKE-Nefedov Team

    2003-03-01

    In this paper we report the first observation on submicron dust particle clouds grown in a radio-frequency sputtering discharge under microgravity conditions. These results have been obtained in the PKE-Nefedov (Plasma Kristall Experiment) chamber in the framework of a French-German-Russian programme. A dust-free region, usually called the `void', is observed in the laboratory and under microgravity conditions even with submicron particles. In this region, successive generations of particles can be grown, leading to the coexistence of particles with various sizes. Each generation of particles constitutes a cloud separated from the others by a definite sheath. Dynamics of these clouds have been investigated showing vortex-like motions or independent behaviour of small heaps of particles, emphasizing both attractive and repulsive effects between dust clouds. As these particles drastically influence the plasma properties, the growth kinetics is followed through the evolution of the discharge current.

  12. Granulometric profiling of aeolian dust deposits by automated image analysis

    NASA Astrophysics Data System (ADS)

    Varga, György; Újvári, Gábor; Kovács, János; Jakab, Gergely; Kiss, Klaudia; Szalai, Zoltán

    2016-04-01

    Determination of granulometric parameters is of growing interest in the Earth sciences. Particle size data of sedimentary deposits provide insights into the physicochemical environment of transport, accumulation and post-depositional alterations of sedimentary particles, and are important proxies applied in paleoclimatic reconstructions. It is especially true for aeolian dust deposits with a fairly narrow grain size range as a consequence of the extremely selective nature of wind sediment transport. Therefore, various aspects of aeolian sedimentation (wind strength, distance to source(s), possible secondary source regions and modes of sedimentation and transport) can be reconstructed only from precise grain size data. As terrestrial wind-blown deposits are among the most important archives of past environmental changes, proper explanation of the proxy data is a mandatory issue. Automated imaging provides a unique technique to gather direct information on granulometric characteristics of sedimentary particles. Granulometric data obtained from automatic image analysis of Malvern Morphologi G3-ID is a rarely applied new technique for particle size and shape analyses in sedimentary geology. Size and shape data of several hundred thousand (or even million) individual particles were automatically recorded in this study from 15 loess and paleosoil samples from the captured high-resolution images. Several size (e.g. circle-equivalent diameter, major axis, length, width, area) and shape parameters (e.g. elongation, circularity, convexity) were calculated by the instrument software. At the same time, the mean light intensity after transmission through each particle is automatically collected by the system as a proxy of optical properties of the material. Intensity values are dependent on chemical composition and/or thickness of the particles. The results of the automated imaging were compared to particle size data determined by three different laser diffraction instruments

  13. Effect of a commercial air ionizer on dust mites Dermatophagoides pteronyssinus and Dermatophagoides farinae (Acari: Pyroglyphidae) in the laboratory

    PubMed Central

    Abidin, Suhaili Zainal; Ming, Ho Tze

    2012-01-01

    Objective To investigate the short and long term efficacy of a commercial air ionizer in killing Dermatophagoides pteronyssinus (D. pteronyssinus) and Dermatophagoides farinae (D. farinae) mites. Methods The effect of a commercial ionizer on D. pteronyssinus and D. farinae was evaluated in the laboratory, using a specially designed test. Mortality was assessed after 6, 16 and 24 hours for direct exposure and after 24, 36, 48, 60 and 72 hours for exposure in simulated mattress. New batches of mites were used for each exposure time. Results LT50 for direct exposure of ionizer was 10 hours for D. pteronyssinus and 18 hours for D. farinae. The LT50 for exposure in simulated mattress was 132 hours or 5.5 days for D. pteronyssinus and 72 hours or 3 days for D. farinae. LT95 for direct exposure of ionizer was 36 hours for D. pteronyssinus and D. farinae. Meanwhile, the LT95 for exposure in simulated mattress was 956 hours or 39.8 days for D. pteronyssinus and 403 hours or 16.8 days for D. farinae. Conclusions This study demonstrates the increasing mite mortalities with increasing exposure time of a commercial ionizer and suggests that negative ions produced by an ionizer kill dust mites and can be used to reduce natural mite populations on exposed surfaces such as floors, clothes, curtains, etc. However, there is reduced efficacy on mites inside stuffed materials as in mattresses and furniture. PMID:23569888

  14. Spectro-polarimetry of Ice-dust Mixtures measured in the Laboratory with Application to the Solar System and Beyond

    NASA Astrophysics Data System (ADS)

    Poch, O.; Schmid, H. M.; Pommerol, A.; Jost, B.; Brouet, Y.; Thomas, N.

    2015-12-01

    Polarimetric observations of atmosphere-less Solar System bodies can give clues on the texture and on the physico-chemical composition of their surfaces, as reviewed by Mishchenko et al. (2010) and Bagnulo et al. (2011). Measurements performed in the laboratory on carefully characterized samples can provide reference data that can be used for direct comparison with remote-sensing polarimetric observations. In particular, we want to study the spectral dependence of the polarization and the way it is correlated or not with the surface albedo. In the Laboratory for Outflow Studies of Sublimating Materials (LOSSy) at the University of Bern, we have developed the capability to prepare and analyze optically thick analogues of planetary or cometary surfaces composed of water ice, minerals and carbonaceous compounds. Water-free dust of high porosity can also be produced by sublimation of ice under space-simulated conditions (Pommerol et al., 2015). Here, we present the first results of polarization measurements performed in the LOSSy. A Stokes polarimeter is used to measure the Stokes parameters describing the polarization of the visible light scattered by icy samples illuminated with a randomly polarized light simulating the star light. Additionally, a radio-goniometer, equipped with polarizers, can also measure the phase angle dependence of the linearly polarized scattered light. These measurements could provide interesting inputs to complement the theoretical models and predict or interpret spectro-polarimetric properties of Solar System objects and circumstellar disks. Mishchenko, M., et al., 2010, Polarimetric Remote Sensing of Solar System Objects. Bagnulo, S., et al., 2011, J. Quant. Spectrosc. Ra. 112, 2059. Pommerol, A., et al., 2015, Planet. Space Sci. 109-110, 106-122.

  15. The Herschel Virgo Cluster Survey. IV. Resolved dust analysis of spiral galaxies

    NASA Astrophysics Data System (ADS)

    Smith, M. W. L.; Vlahakis, C.; Baes, M.; Bendo, G. J.; Bianchi, S.; Bomans, D. J.; Boselli, A.; Clemens, M.; Corbelli, E.; Cortese, L.; Dariush, A.; Davies, J. I.; De Looze, I.; di Serego Alighieri, S.; Fadda, D.; Fritz, J.; Garcia-Appadoo, D. A.; Gavazzi, G.; Giovanardi, C.; Grossi, M.; Hughes, T. M.; Hunt, L. K.; Jones, A. P.; Madden, S.; Pierini, D.; Pohlen, M.; Sabatini, S.; Verstappen, J.; Xilouris, E. M.; Zibetti, S.

    2010-07-01

    We present a resolved dust analysis of three of the largest angular size spiral galaxies, NGC 4501 and NGC 4567/8, in the Herschel Virgo Cluster Survey (HeViCS) science demonstration field. Herschel has unprecedented spatial resolution at far-infrared wavelengths and with the PACS and SPIRE instruments samples both sides of the peak in the far infrared spectral energy distribution (SED). We present maps of dust temperature, dust mass, and gas-to-dust ratio, produced by fitting modified black bodies to the SED for each pixel. We find that the distribution of dust temperature in both systems is in the range ~19-22 K and peaks away from the centres of the galaxies. The distribution of dust mass in both systems is symmetrical and exhibits a single peak coincident with the galaxy centres. This Letter provides a first insight into the future analysis possible with a large sample of resolved galaxies to be observed by Herschel. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  16. Idaho National Laboratory Quarterly Occurrence Analysis

    SciTech Connect

    Mitchell, Lisbeth Ann

    2015-11-01

    This report is published quarterly by the Idaho National Laboratory (INL) Quality and Performance Management Organization. The Department of Energy (DOE) Occurrence Reporting and Processing System (ORPS), as prescribed in DOE Order 232.2, “Occurrence Reporting and Processing of Operations Information,” requires a quarterly analysis of events, both reportable and not reportable, for the previous 12 months. This report is the analysis of 85 reportable events (18 from the 4th Qtr FY-15 and 67 from the prior three reporting quarters), as well as 25 other issue reports (including events found to be not reportable and Significant Category A and B conditions) identified at INL during the past 12 months (8 from this quarter and 17 from the prior three quarters).

  17. Idaho National Laboratory Quarterly Performance Analysis

    SciTech Connect

    Mitchell, Lisbeth

    2014-11-01

    This report is published quarterly by the Idaho National Laboratory (INL) Quality and Performance Management Organization. The Department of Energy (DOE) Occurrence Reporting and Processing System (ORPS), as prescribed in DOE Order 232.2, “Occurrence Reporting and Processing of Operations Information,” requires a quarterly analysis of events, both reportable and not reportable, for the previous 12 months. This report is the analysis of 60 reportable events (23 from the 4th Qtr FY14 and 37 from the prior three reporting quarters) as well as 58 other issue reports (including not reportable events and Significant Category A and B conditions) identified at INL from July 2013 through October 2014. Battelle Energy Alliance (BEA) operates the INL under contract DE AC07 051D14517.

  18. On the dust load and rainfall relationship in South Asia: an analysis from CMIP5

    NASA Astrophysics Data System (ADS)

    Singh, Charu; Ganguly, Dilip; Dash, S. K.

    2017-03-01

    This study is aimed at examining the consistency of the relationship between load of dust and rainfall simulated by different climate models and its implication for the Indian summer monsoon system. Monthly mean outputs of 12 climate models, obtained from the archive of the Coupled Model Intercomparison Project phase 5 (CMIP5) for the period 1951-2004, are analyzed to investigate the relationship between dust and rainfall. Comparative analysis of the model simulated precipitation with the India Meteorological Department (IMD) gridded rainfall, CRU TS3.21 and GPCP version 2.2 data sets show significant differences between the spatial patterns of JJAS rainfall as well as annual cycle of rainfall simulated by various models and observations. Similarly, significant inter-model differences are also noted in the simulation of load of dust, nevertheless it is further noted that most of the CMIP5 models are able to capture the major dust sources across the study region. Although the scatter plot analysis and the lead-lag pattern correlation between the dust load and the rainfall show strong relationship between the dust load over distant sources and the rainfall in the South Asian region in individual models, the temporal scale of this association indicates large differences amongst the models. Our results caution that it would be pre-mature to draw any robust conclusions on the time scale of the relationship between dust and the rainfall in the South Asian region based on either CMIP5 results or limited number of previous studies. Hence, we would like to emphasize upon the fact that any conclusions drawn on the relationship between the dust load and the South Asian rainfall using model simulation is highly dependent on the degree of complexity incorporated in those models such as the representation of aerosol life cycle, their interaction with clouds, precipitation and other components of the climate system.

  19. Dust Astronomy: New venues in interplanetary and interstellar dust research

    NASA Astrophysics Data System (ADS)

    Grün, E.; Hahn, J.; Hamilton, D.; Harris, W.; Horanyi, Mihaly; Huestis, D. L.; Krivov, Alexander; Levasseur-Regourd, A. C.; Liou, J. C.; Lisse, C.; Kuchner, M.; Meisel, D.; Reach, W. T.; Snow, T. P.; Stansberry, J.; Sykes, M.; Yano, H.; Zolensky, M.

    2001-11-01

    Dust particles, like photons, are born at remote sites in space and time. From knowledge of the dust particles' birthplace, and the particles' bulk properties, we can learn about the remote environment out of which the particles were formed and how those particles have evolved physically and dynamically. Remote sensing and in-situ methods, combined with sample analysis and theory, allow us to make a global assessment of dust origin and production in our solar system and its context within the local interstellar environment. Born in the expanding atmospheres of high-luminosity stars or in supernova remnants, interstellar grains provide the seeds that grow in cool interstellar clouds by accretion of atoms and molecules and by agglomeration. Ultimately, interstellar grains can be incorporated in newly forming stars, or they can become part of planetary systems. Reborn from comets, asteroids, Kuiper belt objects and satellites, inter- and circumplanetary dust particles populate our own planetary system. Key issues addressed by space measurements are: - Determination of the total inventory of dust (size, composition, shape, spatial distribution, and temporal variations) in the Solar System. - Characterization and analysis of interstellar dust inside and outside the heliosphere. - Exploration of the dusty environments in the F-corona, near comets, in the asteroid belt and in the Kuiper belt. - Determination of sources, dynamics, and sinks of dust in planetary environs (from Mercury to Pluto). These issues will be supported by ground-based observations, theoretical modeling studies and laboratory measurements.

  20. Metagenomic Analysis of Airborne Bacterial Community and Diversity in Seoul, Korea, during December 2014, Asian Dust Event

    PubMed Central

    Cha, Seho; Srinivasan, Sathiyaraj; Jang, Jun Hyeong; Lee, Dongwook; Lim, Sora; Kim, Kyung Sang; Jheong, Weonhwa; Lee, Dong-Won; Park, Eung-Roh; Chung, Hyun-Mi; Choe, Joonho; Kim, Myung Kyum; Seo, Taegun

    2017-01-01

    Asian dust or yellow sand events in East Asia are a major issue of environmental contamination and human health, causing increasing concern. A high amount of dust particles, especially called as particulate matter 10 (PM10), is transported by the wind from the arid and semi-arid tracks to the Korean peninsula, bringing a bacterial population that alters the terrestrial and atmospheric microbial communities. In this study, we aimed to explore the bacterial populations of Asian dust samples collected during November–December 2014. The dust samples were collected using the impinger method, and the hypervariable regions of the 16S rRNA gene were amplified using PCR followed by pyrosequencing. Analysis of the sequencing data were performed using Mothur software. The data showed that the number of operational taxonomic units and diversity index during Asian dust events were higher than those during non-Asian dust events. At the phylum level, the proportions of Proteobacteria, Actinobacteria, and Firmicutes were different between Asian dust and non-Asian dust samples. At the genus level, the proportions of the genus Bacillus (6.9%), Arthrobacter (3.6%), Blastocatella (2%), Planomicrobium (1.4%) were increased during Asian dust compared to those in non-Asian dust samples. This study showed that the significant relationship between bacterial populations of Asian dust samples and non-Asian dust samples in Korea, which could significantly affect the microbial population in the environment. PMID:28122054

  1. Comparison of particle size distribution data obtained with cascade impaction samplers and from Voulter counter analysis of total dust samples

    SciTech Connect

    Treaftis, H.N.; Kacsmar, P.; Suppers, K., Tomb, T.F.

    1986-02-01

    The paper discusses the results of a study conducted to evaluate two different methods used to measure the particle size distribution of an aerosol. Comparative samples were collected in the laboratory with Sierra's Models 260 and 298 cascade impaction samplers and a sampler consisting of a pump and filter using coal and limestone aerosols of varying particle size distributions. The particle size distributions determined from each of the impaction samples were compared to each other as well as to the particle size distribution determined from data obtained from a Coulter Counter analysis of the total dust sample collected on the filter. The results of the laboratory study are discussed and compared to a limited amount of similar data obtained from samples collected with the impaction samplers in underground coal mines.

  2. NASA Laboratory Analysis for Manned Exploration Missions

    NASA Technical Reports Server (NTRS)

    Krihak, Michael (Editor); Shaw, Tianna

    2014-01-01

    The Exploration Laboratory Analysis (ELA) project supports the Exploration Medical Capability Element under the NASA Human Research Program. ELA instrumentation is identified as an essential capability for future exploration missions to diagnose and treat evidence-based medical conditions. However, mission architecture limits the medical equipment, consumables, and procedures that will be available to treat medical conditions during human exploration missions. Allocated resources such as mass, power, volume, and crew time must be used efficiently to optimize the delivery of in-flight medical care. Although commercial instruments can provide the blood and urine based measurements required for exploration missions, these commercial-off-the-shelf devices are prohibitive for deployment in the space environment. The objective of the ELA project is to close the technology gap of current minimally invasive laboratory capabilities and analytical measurements in a manner that the mission architecture constraints impose on exploration missions. Besides micro gravity and radiation tolerances, other principal issues that generally fail to meet NASA requirements include excessive mass, volume, power and consumables, and nominal reagent shelf-life. Though manned exploration missions will not occur for nearly a decade, NASA has already taken strides towards meeting the development of ELA medical diagnostics by developing mission requirements and concepts of operations that are coupled with strategic investments and partnerships towards meeting these challenges. This paper focuses on the remote environment, its challenges, biomedical diagnostics requirements and candidate technologies that may lead to successful blood/urine chemistry and biomolecular measurements in future space exploration missions. SUMMARY The NASA Exploration Laboratory Analysis project seeks to develop capability to diagnose anticipated space exploration medical conditions on future manned missions. To achieve

  3. Automated SIMS Isotopic Analysis Of Small Dust Particles

    NASA Astrophysics Data System (ADS)

    Nittler, L.; Alexander, C.; Gyngard, F.; Morgand, A.; Zinner, E. K.

    2009-12-01

    The isotopic compositions of sub-μm to μm sized dust grains are of increasing interest in cosmochemistry, nuclear forensics and terrestrial aerosol research. Because of its high sensitivity and spatial resolution, Secondary Ion Mass Spectrometry (SIMS) is the tool of choice for measuring isotopes in such small samples. Indeed, SIMS has enabled an entirely new sub-field of astronomy: presolar grains in meteorites. In recent years, the development of the Cameca NanoSIMS ion probe has extended the reach of isotopic measurements to particles as small as 100 nm in diameter, a regime where isotopic precision is strongly limited by the total number of atoms in the sample. Many applications require obtaining isotopic data on large numbers of particles, necessitating the development of automated techniques. One such method is isotopic imaging, wherein images of multiple isotopes are acquired, each containing multiple dispersed particles, and image processing is used to determine isotopic ratios for individual particles. This method is powerful, but relatively inefficient for raster-based imaging on the NanoSIMS. Modern computerized control of instrumentation has allowed for another approach, analogous to commercial automated SEM-EDS particle analysis systems, in which images are used solely to locate particles followed by fully automated grain-by-grain analysis. The first such system was developed on the Carnegie Institution’s Cameca ims-6f, and was used to generate large databases of presolar grains. We have recently developed a similar system for the NanoSIMS, whose high sensitivity allows for smaller grains to be analyzed with less sample consumption than is possible with the 6f system. The 6f and NanoSIMS systems are functionally identical: an image of dispersed grains is obtained with sufficient statistical precision for an algorithm to identify the positions of individual particles, the primary ion beam is deflected to each particle in turn and rastered in a small

  4. Biopersistent Granular Dust and Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis

    PubMed Central

    Brüske, Irene; Thiering, Elisabeth; Heinrich, Joachim; Huster, Katharina; Nowak, Dennis

    2013-01-01

    Objective Applying a systematic review to identify studies eligible for meta-analysis of the association between occupational exposure to inorganic dust and the development of chronic obstructive pulmonary disease (COPD), and conducting a meta-analysis. Data Sources Searches of PubMed and Embase for the time period 1970–2010 yielded 257 cross-sectional and longitudinal studies on people exposed to inorganic dust at the workplace with data on lung function. These studies were independently abstracted and evaluated by two authors; any disagreement was resolved by a third reviewer. Of 55 publications accepted for meta-analysis, 27 investigated the effects of occupational exposure to biopersistent granular dust (bg-dust). Methods A random effects meta-analysis allowed us to provide an estimate of the average exposure effect on spirometric parameters presented in forest plots. Between-study heterogeneity was assessed by using I2 statistics, with I2>25% indicating significant heterogeneity. Publication bias was investigated by visual inspection of funnel plots. The influence of individual studies was assessed by dropping the respective study before pooling study-specific estimates. Results The mean FEV1 of workers exposed to bg-dust was 160 ml lower or 5.7% less than predicted compared to workers with no/low exposure. The risk of an obstructive airway disease—defined as FEV1/FVC < 70%—increased by 7% per 1 mg· m-3 respirable bg-dust. Conclusion Occupational inhalative exposure to bg-dust was associated with a statistically significant decreased FEV1 and FEV1/FVC revealing airway obstruction consistent with COPD. PMID:24278358

  5. Spatial and Temporal Dust Source Variability in Northern China Identified Using Advanced Remote Sensing Analysis

    NASA Technical Reports Server (NTRS)

    Taramelli, A.; Pasqui, M.; Barbour, J.; Kirschbaum, D.; Bottai, L.; Busillo, C.; Calastrini, F.; Guarnieri, F.; Small, C.

    2013-01-01

    The aim of this research is to provide a detailed characterization of spatial patterns and temporal trends in the regional and local dust source areas within the desert of the Alashan Prefecture (Inner Mongolia, China). This problem was approached through multi-scale remote sensing analysis of vegetation changes. The primary requirements for this regional analysis are high spatial and spectral resolution data, accurate spectral calibration and good temporal resolution with a suitable temporal baseline. Landsat analysis and field validation along with the low spatial resolution classifications from MODIS and AVHRR are combined to provide a reliable characterization of the different potential dust-producing sources. The representation of intra-annual and inter-annual Normalized Difference Vegetation Index (NDVI) trend to assess land cover discrimination for mapping potential dust source using MODIS and AVHRR at larger scale is enhanced by Landsat Spectral Mixing Analysis (SMA). The combined methodology is to determine the extent to which Landsat can distinguish important soils types in order to better understand how soil reflectance behaves at seasonal and inter-annual timescales. As a final result mapping soil surface properties using SMA is representative of responses of different land and soil cover previously identified by NDVI trend. The results could be used in dust emission models even if they are not reflecting aggregate formation, soil stability or particle coatings showing to be critical for accurately represent dust source over different regional and local emitting areas.

  6. Laboratory polarization and permittivity measurements to interpret dust polarimetric observations and in-situ radar studies. Significance for Rosetta mission at 67P/Churyumov-Gerasimenko

    NASA Astrophysics Data System (ADS)

    Levasseur-Regourd, Anny-Chantal; Brouet, Yann; Hadamcik, Edith; Heggy, Essam; Hines, Dean; Lasue, Jérémie; Renard, Jean-Baptiste

    2015-08-01

    Polarimetric astronomical observations on dust clouds and regolithic surfaces require laboratory simulations on samples to provide information on properties (size distribution, porosity, refractive index) of the scattering media. Similarly, in-situ radar investigations in the solar system require laboratory studies on samples to infer physical properties (e.g. porosity, ice/dust ratio) of sub-surfaces and interiors. Recent developments are illustrated with present studies related to the Rosetta mission, which begun its rendezvous with comet 67P/Churyumov-Gerasimeko (C-G) and landed the Philae module on its nucleus in 2014.We will summarize laboratory simulations with the PROGRA2 suite of instruments that study (in the visible to near IR domain) the polarimetric properties of dust samples in microgravity conditions or on surfaces [1], with emphasis on the interpretation of polarimetric observations of C-G, during its previous perihelion passages from Earth observatories, and currently from HST [2,3]. The presence of large dust particles in the pre-perihelion coma previously inferred from remote observations agrees with Rosetta ground truth [4]. We will also present measurements on the permittivity (in the millimeter to meter domain) of various dust samples, with emphasis on porous samples [5,6]. Results provide constraints on the properties of the subsurface and interior of C-G, as explored by MIRO on Rosetta and CONSERT on Philae.Such studies are relevant for the interpretation of polarimetric observations of other dust clouds (e.g. debris disks, interplanetary dust cloud, clouds in planetary atmospheres) and surfaces (e.g. planets, moons), as well as for those of other radar characterization studies (e.g. Mars, moons, asteroids).[1] Levasseur-Regourd et al. In Polarization of stars and planetary systems, Cambridge UP, in press 2015.[2] Hadamcik et al. A&A 517 2010.[3] Hines and Levasseur-Regourd, PSS submitted 2015.[4] Schulz et al. Nature 518 2015.[5] Heggy et al

  7. NASA Laboratory Analysis for Manned Exploration Missions

    NASA Technical Reports Server (NTRS)

    Krihak, Michael K.; Shaw, Tianna E.

    2014-01-01

    The Exploration Laboratory Analysis (ELA) project supports the Exploration Medical Capability Element under the NASA Human Research Program. ELA instrumentation is identified as an essential capability for future exploration missions to diagnose and treat evidence-based medical conditions. However, mission architecture limits the medical equipment, consumables, and procedures that will be available to treat medical conditions during human exploration missions. Allocated resources such as mass, power, volume, and crew time must be used efficiently to optimize the delivery of in-flight medical care. Although commercial instruments can provide the blood and urine based measurements required for exploration missions, these commercial-off-the-shelf devices are prohibitive for deployment in the space environment. The objective of the ELA project is to close the technology gap of current minimally invasive laboratory capabilities and analytical measurements in a manner that the mission architecture constraints impose on exploration missions. Besides micro gravity and radiation tolerances, other principal issues that generally fail to meet NASA requirements include excessive mass, volume, power and consumables, and nominal reagent shelf-life. Though manned exploration missions will not occur for nearly a decade, NASA has already taken strides towards meeting the development of ELA medical diagnostics by developing mission requirements and concepts of operations that are coupled with strategic investments and partnerships towards meeting these challenges. This paper focuses on the remote environment, its challenges, biomedical diagnostics requirements and candidate technologies that may lead to successful blood-urine chemistry and biomolecular measurements in future space exploration missions.

  8. Further Analysis on the Mystery of the Surveyor III Dust Deposits

    NASA Technical Reports Server (NTRS)

    Metzger, Philip; Hintze, Paul; Trigwell, Steven; Lane, John

    2011-01-01

    The Apollo 12 lunar module (LM) landing near the Surveyor 1lI spacecraft at the end of 1969 has remained the primary experimental verification of the predicted physics of plume ejecta effects from a rocket engine interacting with the surface of the moon. This was made possible by the return of the Surveyor 1lI camera housing by the Apollo 12 astronauts, allowing detailed analysis of the composition of dust deposited by the Apollo 12 LM plume. It was soon realized after the initial analysis of the camera housing that the LM plume tended to remove more dust than it had deposited. In the present study, coupons from the camera housing were reexamined by a KSC research team using SEM/EDS and XPS analysis. In addition, plume effects recorded in landing videos from each Apollo mission have been studied for possible clues. Several likely scenarios are proposed to explain the Surveyor III dust observations. These include electrostatic attraction of the dust to the surface of the Surveyor as a result of electrostatic charging of the jet gas exiting the engine nozzle during descent; dust blown by the Apollo 12 LM fly-by while on its descent trajectory; dust ejected from the lunar surface due to gas forced into the soil by the Surveyor 1lI rocket nozzle, based on Darcy's law; and mechanical movement of dust during the Surveyor landing. Even though an absolute answer is not possible based on available data and theory, various computational models are employed to estimate the feasibility of each of these proposed mechanisms. Scenarios are then discussed which combine multiple mechanisms to produce results consistent with observations.

  9. Comparison of coal mine dust size distributions and calibration standards for crystalline silica analysis.

    PubMed

    Page, Steven J

    2003-01-01

    Since 1982 standard calibration materials recommended for respirable crystalline silica analysis by the Mine Safety and Health Administration (MSHA) P7 Infrared Method and the National Institute for Occupational Safety and Health (NIOSH) X-ray Diffraction (XRD) Analytical Method 7500 have undergone minor changes in size distribution. However, a critical assumption has been made that the crystalline silica in ambient mine atmosphere respirable dust samples has also remained essentially unchanged in particle size distribution. Therefore, this work compared recent particle size distributions of underground coal mine dust and the silica component of these dusts with estimated aerodynamic particle size distributions of calibration standard materials MIN-U-SIL 5, Berkeley 5, and SRM 1878 used by two crystalline silica analysis techniques. Dust impactor sampling data for various locations in 13 underground coal mines were analyzed for the respirable mass median aerodynamic diameters. The data suggest that the MSHA P7 method will underestimate the silica content of the sample by at most 7.4% in the median size range 0.9 to 3.6 microm, and that it is unlikely one would obtain any significant error in the MSHA P7 method analysis when the method uses Berkeley 5, MIN-U-SIL 5, or SRM 1878 as a calibration standard material. The results suggest that the NIOSH Analytical Method 7500 would be more appropriate for a dust sample that is representative of the total (no cyclone classifier) rather than the respirable airborne dust, particularly because the mass fraction in the size range below 4 microm is usually a small percentage of the total airborne dust mass. However, NIOSH Analytical Method 7500 is likely to underestimate the silica content of an airborne respirable dust sample by only 5 to 10%. The results of this study also suggest that any changes that may have occurred in the median respirable size of airborne coal mine dust are not significant enough to cause any appreciable

  10. Flying Through Dust From Asteroids

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-11-01

    How can we tell what an asteroid is made of? Until now, weve relied on remote spectral observations, though NASAs recently launched OSIRIS-REx mission may soon change this by landing on an asteroid and returning with a sample.But what if we could learn more about the asteroids near Earth without needing to land on each one? It turns out that we can by flying through their dust.The aerogel dust collector of the Stardust mission. [NASA/JPL/Caltech]Ejected CluesWhen an airless body is impacted by the meteoroids prevalent throughout our solar system, ejecta from the body are flung into the space around it. In the case of small objects like asteroids, their gravitational pull is so weak that most of the ejected material escapes, forming a surrounding cloud of dust.By flying a spacecraft through this cloud, we could perform chemical analysis of the dust, thereby determining the asteroids composition. We could even capture some of the dust during a flyby (for example, by using an aerogel collector like in the Stardust mission) and bring it back home to analyze.So whats the best place to fly a dust-analyzing or -collecting spacecraft? To answer this, we need to know what the typical distribution of dust is around a near-Earth asteroid (NEA) a problem that scientists Jamey Szalay (Southwest Research Institute) and Mihly Hornyi (University of Colorado Boulder) address in a recent study.The colors show the density distribution for dust grains larger than 0.3 m around a body with a 10-km radius. The distribution is asymmetric, with higher densities on the apex side, shown here in the +y direction. [Szalay Hornyi 2016]Moon as a LaboratoryTo determine typical dust distributions around NEAs, Szalay and Hornyi first look at the distribution of dust around our own Moon, caused by the same barrage of meteorites wed expect to impact NEAs. The Moons dust cloud was measured in situ in 2013 and 2014 by the Lunar Dust Experiment (LDEX) on board the Lunar Atmosphere and Dust Environment

  11. Mineralogical analysis of attic dust samples for contamination source identification in an industrial area, Ajka, Hungary

    NASA Astrophysics Data System (ADS)

    Völgyesi, Péter; Jordan, Gyozo; Gosar, Mateja; Szabó, Csaba; Miler, Miloš; Kónya, Péter; Bartha, András

    2013-04-01

    The post-war centrally directed economy forced massive heavy industry in Hungary, producing huge amount of wastes and pollution. Long-term airborne emissions from mining, coal-fired power plants and alumina industry have left the legacy of widely distributed contamination around industrial areas and nearby settlements in the Ajka region. Recent research suggests that significant amount of airborne pollutants, deposited in the urban environment, can be efficiently studied by attic dust analysis. The sampling strategy followed a grid-based stratified random sampling design and 30 samples were collected in 27 houses (at least 30 years old) in a 8x8 grid of the 64 km2 project area. In order to determine the pollution potential of attic dust samples, geochemical and mineralogical analyses were performed. The main aim of the mineralogical analyses was to study the phase composition of the dust particles and to identify potential anthropogenic sources. The total concentrations of the toxic elements (As, Pb, Cd, Cu, Ni and Zn) were measured with ICP-OES and mercury content was analyzed with atomic absorption spectrometry. Phase analyses of the samples were carried out by the means of scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) and X-Ray diffraction (XRD) methods. Laser particle size analyzer was used to measure the grain size of attic dust particles. Results showed that the studied attic dust in the Ajka urban area was contaminated mostly by Hg, Pb and Zn with contents ranging between 0.1-2 ppm, 42.5-881 ppm and 90.2-954 ppm, respectively. However, the study of extreme data values (statistical outliers) has shown that at certain points airborne dust can be extremely contaminated also with Cd (0.4-11.7 ppm). The size of the attic dust particles varied between 0.2 and 113 µm. Based on the SEM/EDS and XRD analysis, the most frequently identified mineralogical phases were quartz, calcite, gypsum and Fe- and Al-bearing phases. Fe

  12. Laboratory Measurements on Charging of Individual Micron-Size Apollo-11 Dust Grains by Secondary Electron Emission

    NASA Astrophysics Data System (ADS)

    Tankosic, D.; Abbas, M. M.

    2012-03-01

    We present some examples of the complex nature of secondary electron emissions from lunar dust grains levitated in an electrodynamic balance, and show that the measurements are unaffected by the variation of the AC field employed in the experiments.

  13. Laboratory Measurement of the Optical Properties of Hematite and Desert Dust Aerosols to Assess Their Climate Forcing

    NASA Astrophysics Data System (ADS)

    Moosmuller, H.; Aiken, A. C.; Dubey, M. K.; Frey, G.; Garro, B.; Engelbrecht, J. P.

    2012-12-01

    Globally, aerosol mass emissions and optical depths are dominated by entrained mineral dust. While most minerals occurring in dust aerosols do not absorb solar radiation, some minerals cause significant absorption, thereby lowering the single scatter albedo (SSA) significantly below one, potentially contributing to a warmer and drier atmosphere. Therefore, the optical properties of globally relevant dust aerosols need to be characterized to reduce uncertainties in their radiative forcings. A well-known absorbing component found in dust aerosols is hematite, Fe2O3, which absorbs strongly in the blue-green spectral region, giving some soils, rocks, and dust aerosols their characteristic red color. We discuss measurements of the optical properties of ~30 dust aerosols, including a pure hematite standard, hematite-containing mineral dust standards ranging from 9-34% hematite by mass, and various dust samples collected from around the world. Samples are suspended from aqueous solution and/or from dry atomization with a cyclone re-suspension chamber yielding the fine fraction relevant for long-range transport. Size distributions were characterized with an optical aerosol spectrometer; absorption and scattering coefficients were measured with a three-wavelength photoacoustic soot spectrometer (PASS-3) at 405, 532, and 781 nm and with an ultraviolet photoacoustic soot spectrometer (PASS-UV) at 375 nm yielding wavelength-dependent mass absorption coefficients (MAC's), SSA's, and wavelength dependent Angstrom exponents. Hematite MAC's are an order of magnitude smaller than those of black carbon (BC) at 405 nm and 532 nm and are largely non-absorbing at 781 nm with SSA's of 0.49 0.68 and 0.98, respectively.

  14. Analysis of chondritic interplanetary dust thin-sections

    NASA Astrophysics Data System (ADS)

    Bradley, J. P.

    1988-04-01

    Chondritic interplanetary dust particles (IDPs) are heterogeneous aggregates of predominantly submicron mineral grains and carbonaceous material, whose bulk compositions agree within a factor of two with type CI/CM carbonaceous chondrites. The mineralogy and petrography of 25 such particles were studied by analytical electron microscopic examination of ultramicrotomed thin sections (500-1000 A thick). Four classes of chondritic IDPs were recognized, referred to as pyroxene, olivine, smectite, and serpentine, and their relative abundances were 9:4:10:2, respectively. Quantitative thin-film analyses indicate that pyroxene particles most closely resemble material emitted from comet Halley. Smectite particles may have formed from pyroxene particles by aqueous alteration of glass and enstatite crystals. Serpentine particles are the only class that are similar to the matrices of carbonaceous chondrites, but these are the least abundant chondritic IDPs. Collectively, chondritic particles are a mineralogically diverse group of extraterrestrial materials.

  15. An Analysis of Dust Halo and Extinction Toward X Persei

    NASA Technical Reports Server (NTRS)

    Valencic, Lynne A.; Smith, Randall K.

    2007-01-01

    Interstellar dust grain models are not sufficiently constrained by UV extinction curves to be able to distinguish between them. By testing grain models in the X-ray regime and applying elemental abundance constraints, we show to what extent the models can reproduce the observables in these regimes, and if they are capable of doing so while respecting the abundance limits. We tested the MRN and WD grain models. The fits to the X-ray data do not allow us to distinguish between MRN and WD; both models provide reasonable fits, but cannot do so while respecting the elemental abundance constraints. The situation in the UV regime is similar. Both MRN and WD underestimate the hydrogen column density NH. The model of ZDA provides promising results, as it finds NH much closer to the UV-measured value; further testing of this model is called for.

  16. Laboratory Drop Towers for the Experimental Simulation of Dust-aggregate Collisions in the Early Solar System

    PubMed Central

    Blum, Jürgen; Beitz, Eike; Bukhari, Mohtashim; Gundlach, Bastian; Hagemann, Jan-Hendrik; Heißelmann, Daniel; Kothe, Stefan; Schräpler, Rainer; von Borstel, Ingo; Weidling, René

    2014-01-01

    For the purpose of investigating the evolution of dust aggregates in the early Solar System, we developed two vacuum drop towers in which fragile dust aggregates with sizes up to ~10 cm and porosities up to 70% can be collided. One of the drop towers is primarily used for very low impact speeds down to below 0.01 m/sec and makes use of a double release mechanism. Collisions are recorded in stereo-view by two high-speed cameras, which fall along the glass vacuum tube in the center-of-mass frame of the two dust aggregates. The other free-fall tower makes use of an electromagnetic accelerator that is capable of gently accelerating dust aggregates to up to 5 m/sec. In combination with the release of another dust aggregate to free fall, collision speeds up to ~10 m/sec can be achieved. Here, two fixed high-speed cameras record the collision events. In both drop towers, the dust aggregates are in free fall during the collision so that they are weightless and match the conditions in the early Solar System. PMID:24962693

  17. Laboratory drop towers for the experimental simulation of dust-aggregate collisions in the early solar system.

    PubMed

    Blum, Jürgen; Beitz, Eike; Bukhari, Mohtashim; Gundlach, Bastian; Hagemann, Jan-Hendrik; Heißelmann, Daniel; Kothe, Stefan; Schräpler, Rainer; von Borstel, Ingo; Weidling, René

    2014-06-05

    For the purpose of investigating the evolution of dust aggregates in the early Solar System, we developed two vacuum drop towers in which fragile dust aggregates with sizes up to ~10 cm and porosities up to 70% can be collided. One of the drop towers is primarily used for very low impact speeds down to below 0.01 m/sec and makes use of a double release mechanism. Collisions are recorded in stereo-view by two high-speed cameras, which fall along the glass vacuum tube in the center-of-mass frame of the two dust aggregates. The other free-fall tower makes use of an electromagnetic accelerator that is capable of gently accelerating dust aggregates to up to 5 m/sec. In combination with the release of another dust aggregate to free fall, collision speeds up to ~10 m/sec can be achieved. Here, two fixed high-speed cameras record the collision events. In both drop towers, the dust aggregates are in free fall during the collision so that they are weightless and match the conditions in the early Solar System.

  18. Analysis of the Impact of Major Dust Events on the Aerosols Characteristics over Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Farahat, Ashraf; El-Askary, Hesham; Al-Shaibani, Abdulaziz; Hariri, Mustafa M.

    2015-04-01

    The Kingdom of Saudi Arabia is a major source of atmospheric dust. Frequent dust storms blow up and significantly affect human activities, airports and citizens' health. Aerosols optical and physical characteristics are influenced by major dust storms outbreaks. In this, paper, ground based AERONET measurements are integrated with space-borne sensors, namely MODIS and CALIPSO to analyze aerosols' characteristics during March - May of 2009 where a massive dust storm blew up and caused a widespread heavy atmospheric dust load over Saudi Arabia and the same period during 2010, where less dust activities were reported. The MODIS Deep Blue AOD analysis showed similar aerosols pattern over the land, however a substantial variance in aerosol loading during March - May 2009 compared with the same period in 2010 was observed. The angstrom exponent analysis showed that the majority of aerosol measurements in 2009 and 2010 are dominated by coarse-mode particles with angstrom exponent < 0.5. Detailed analysis of aerosol optical properties shows significant influence of coarse mode particles in the enhanced aerosol loading in 2009. The volume depolarization rations (VDR) derived from CALIPSO backscattering measurements is used to find latitudinal profile of mean aerosol optical depth to indicate the type of particles and to discriminate spherical aerosols with non-spherical particles. Acknowledgement The authors would like to acknowledge the support provided by the King Abdel Aziz City for Science & Technology (KACST) for funding this work under grant No. (MT-32-76). The support provided by the Deanship of Research at King Fahd University of Petroleum & Minerals (KFUPM) is gratefully acknowledged.

  19. Detection of pinworm eggs in the dust of laboratory animals breeding facility, in the cages and on the hands of the technicians.

    PubMed

    Lytvynets, A; Langrova, I; Lachout, J; Vadlejch, J

    2013-01-01

    Pinworms (Nematoda: Oxyurida) are common contaminants in most laboratory rodent colonies. The aim of the study was to monitor the transmission of Syphacia muris eggs in laboratory rat breeding facilities. Dust in a breeding room was investigated using special grids (free fallout, or through the help suction chamber). Furthermore, the ventilation system, breeding cages and the hands of the laboratory technical staff were examined. In the case of free fallout, the percentage of positive grids increased slightly over time: from 5.5% (after 24 h) to 8.2% (72 h). Similar values were also found when using the suction chamber (7.6%). Many more pinworm eggs were found in samples collected every second month from suction holes of the ventilation system (28.7%). One-half of the samples taken from the breeding cages (before washing) exhibited pinworm eggs (50.8%). Examination of the hands of technical staff showed positive detection in 37.9% of cases. In this study, certain transmission factors (dust, unclean cages and technicians) were proved to be significant in the distribution of pinworm infection in laboratory rodent facilities.

  20. Mars Science Laboratory Interplanetary Navigation Analysis

    NASA Technical Reports Server (NTRS)

    Martin-Mur, Tomas J.; Kruizinga, Gerard L.; Wong, Mau C.

    2011-01-01

    The Mars Science Laboratory (MSL) is a NASA rover mission that will be launched in late 2011 and will land on Mars in August of 2012. This paper describes the analyses performed to validate the navigation system for launch, interplanetary cruise, and approach. MSL will use guidance during its descent into Mars in order to minimize landing dispersions, and therefore will be able to use smaller landing zones that are closer to terrain of high scientific interest. This will require a more accurate delivery of the spacecraft to the atmospheric entry interface, and a late update of the state of the spacecraft at entry. During cruise and approach the spacecraft may perform up to six trajectory correction maneuvers (TCMs), to target to the desired landing site with the required flight path angle at entry. Approach orbit determination covariance analyses have been performed to evaluate the accuracy that can be achieved in delivering the spacecraft to the entry interface point, and to determine how accurately the state of the spacecraft can be predicted to initialize the guidance algorithm. In addition, a sensitivity analysis has been performed to evaluate which factors most contribute to the improvement or degradation of the navigation performance, for both entry flight path angle delivery and entry state knowledge.

  1. QUANTITATIVE PCR ANALYSIS OF MOLDS IN THE DUST FROM HOMES OF ASTHMATIC CHILDREN IN NORTH CAROLINA

    EPA Science Inventory

    The vacuum bag (VB) dust was analyzed by mold specific quantitative PCR. These results were compared to the analysis survey calculated for each of the homes. The mean and standard deviation (SD) of the ERMI values in the homes of the NC asthmatic children was 16.4 (6.77), compa...

  2. Transient atmospheric effects of the landing of the Mars Science Laboratory rover: The emission and dissipation of dust and carbazic acid

    NASA Astrophysics Data System (ADS)

    Moores, John E.; Schieber, Juergen; Kling, Alexandre M.; Haberle, Robert M.; Moore, Casey A.; Anderson, Mark S.; Katz, Ira; Yavrouian, Andre; Malin, Michael C.; Olson, Timothy; Rafkin, Scot C. R.; Lemmon, Mark T.; Sullivan, Robert J.; Comeaux, Keith; Vasavada, Ashwin R.

    2016-09-01

    Imaging during and after the landing of the Mars Science Laboratory (MSL) rover in 2012 provides a means to examine two transitory phenomena for the first time: the settling of the plume of material raised by the powered terminal descent, and the possible dispersal of 140 kg of hydrazine into the atmosphere as fine-grained solid carbazic acid. The peri-landing images, acquired by the Mars Descent Imager (MARDI) and the rover hazard cameras (Hazcams), allow the first comparison of post-landing geological assessment of surface deflation with the plume itself. Examination of the Hazcam images acquired over a period of 4011 s shows that only a small fraction (350-1000 kg) of the total mass of fine-grained surface material displaced by the landing (4000 kg) remained in the atmosphere for this duration. Furthermore, a large component of this dust occurs as particles for which the characteristic optical radius is 20-60 μm, preventing them from being substantially mixed with the atmospheric column by eddy diffusion. Examination of the MARDI record over 225 s post-landing reveals a rapidly settling component that comprised approximately 1800-2400 kg and had a larger particle size with an optical radius of 360-470 μm. The possible release of hydrazine by the sky crane stage also may have created particles of carbazic acid that would, analogous to the dust, spread through eddy diffusivity and settle to the ground. Peri-landing Hazcam images of the plume created during sky crane destruction constrains the particle radius to be either less than 23 μm or greater than 400 μm. When combined with a Lagrangian model of the atmosphere, such particle sizes suggest that the carbazic acid was either deposited very near the sky crane crash site, or was widely dispersed as small particles which would have been quickly photodissociated to volatile ammonia and carbon dioxide. Surfaces visited by the MSL rover, Curiosity, would have received at most <0.2 ppb of carbazic acid and levels

  3. An Analysis of Laboratory Safety in Texas.

    ERIC Educational Resources Information Center

    Fuller, Edward J.; Picucci, Ali Callicoatte; Collins, James W.; Swann, Philip

    This paper reports on a survey to discover the types of laboratory accidents that occur in Texas public schools, the factors associated with such accidents, and the practices of schools with regard to current laboratory safety requirements. The purpose of the survey is to better understand safety conditions in Texas public schools and to help…

  4. A detailed petrological analysis of hydrated, low-nickel, nonchondritic stratospheric dust particles

    NASA Astrophysics Data System (ADS)

    Rietmeijer, Frans J. M.

    A detailed petrological analysis of three low-Ni, K-bearing, nonchondritic stratospheric dust particles is performed, and these particles are compared to products of high-energy, explosive (Plinian-type) volcanic events. The analytical electron microscope (AEM) analyses show pervasive layer silicates, carbonate and goethite, and chemical fractionation in the matrix of these particles similar to hydrothermal alteration in volcanic ejecta. Along with low Ni content and the presence of potassium, the texture and mineralogy of particles L2001-18, L2001-20, and L2002 C2 are similar to at least two nonchondritic stratospheric dust particles of the igneous subgroup for which an extraterrestrial origin has been suggested based on their minor- and trace-element abundances. The petrological characteristics of some low-Ni, K-bearing nonchondritic stratospheric dust particles supports a probable terrestrial volcanic origin, but the AEM data alone cannot exclude an extraterrestrial origin for these particles.

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

    NASA Technical Reports Server (NTRS)

    Westphal, A. J.; Allen, C.; Bajit, S.; Bastien, R.; Bechtel, H.; Bleuet, P.; Borg, J.; Brenker, F.; Bridges, J.; Brownlee, D. E.; Burchell, M.; Burghammer, M.; Butterworth, A. L.; Cloetens, P.; Cody, G.; Ferrior, T.; Floss, C.; Flynn, G. J.; Frank, D.; Gainsforth, Z.; Grun, E.; Hoppe, P.; Hudson, B.; Kearsley, A.; Lai, B.

    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.

  6. Respirable quartz dust exposure and airway obstruction: a systematic review and meta-analysis.

    PubMed

    Brüske, Irene; Thiering, Elisabeth; Heinrich, Joachim; Huster, Katharina M; Nowak, Dennis

    2014-08-01

    Studies on exposure to respirable quartz dust at the workplace and the development of chronic obstructive pulmonary disease (COPD) were selected into a systematic review and meta-analysed to obtain an overall estimate of forced expiratory volume in 1 s (FEV1) and FEV1/forced vital capacity (FVC) reduction. PubMed and Embase were searched from 1970 to 2010. In total, 257 cross-sectional and longitudinal studies were identified that reported on inorganic dust exposure and had available lung function data. Of the 55 publications which met our inclusion criteria, 11 reported on associations with occupational exposure to respirable quartz dust. The combined average effect estimate of respirable quartz dust on spirometric parameters was obtained using a random effects model meta-analysis. Between-study heterogeneity was assessed via the I(2) statistic. Most studies found a significant negative association of FEV1 and FEV1/FVC related to increasing exposure to crystalline quartz at the workplace. One study found an effect only for smokers, and one did not observe such an effect at all. The meta-analysis of cross-sectional studies showed that the mean ratio FEV1 to FVC was reduced and FEV1 of workers exposed to respirable quartz dust was 4.6% less than predicted compared with workers with no/low exposure. Both results showed a statistically significant difference. Occupational exposure to respirable quartz dust was associated with a statistically significant decrease in FEV1 and FEV1/FVC, revealing airway obstruction consistent with COPD.

  7. LDEX-PLUS: Lunar Dust Experiment with Chemical Analysis Capability to search for Water

    NASA Astrophysics Data System (ADS)

    Horanyi, M.; Sternovsky, Z.; Gruen, E.; Kempf, S.; Srama, R.; Postberg, F.

    2010-12-01

    The Lunar Dust Experiment (LDEX) onboard the Lunar Atmosphee and Dust Explorer Mission (LADEE) is scheduled for launch in early 2013. It will map the variability of the density and size distributions of dust in the lunar vicinity. LDEX is an impact ionization instrument, at an impact speed of > 1.6 km/s, it is capable of measuring the mass of grains with m > 10^(-11) g, and it can also identify a population of smaller grains with m > 10^(-14) kg with a density of n > 10^(-4) cm^(-3). This talk is to introduce the LDEX-PLUS instrument that extends the LDEX capabilities to also measure the chemical composition of the impacting particles with a mass resolution of M/ΔM > 30. We will summarize the science goals, measurement requirements, and the resource needs of this instrument. Traditional methods to analyze surfaces of airless planetary objects from an orbiter are IR and gamma ray spectroscopy, and neutron backscatter measurements. Here we present a complementary method to analyze dust particles as samples of planetary objects from which they were released. The Moon, Mercury, and all other airless planetary object are exposed to the ambient meteoroid bombardment that erodes their surface and generates secondary ejecta particles. Therefore, such objects are enshrouded in clouds of dust particles that have been lifted from their surfaces. In situ mass spectroscopic analysis of these dust particles impacting onto a detector of an orbiting spacecraft reveals their composition, and the origin of each analyzed grain can be determined with an accuracy at the surface that is approximately the altitude of the orbit. Since the detection rates can be on the order of thousands per day, a spatially resolved mapping of the surface composition can be achieved. Possible enhancements include the addition of a dust trajectory sensor to improve the spatial resolution on the surface to ~ 10 km from an altitude of 100 km, and a reflectron type instrument geometry to increase the

  8. An analysis of employee exposure to organic dust at large-scale composting facilities

    NASA Astrophysics Data System (ADS)

    Sykes, P.; Allen, J. A.; Wildsmith, J. D.; Jones, K. P.

    2009-02-01

    The occupational health implications from exposure to dust, endotoxin and 1-3 β Glucan at commercial composting sites are uncertain. This study aims to establish employee exposure levels to inhalable and respirable dust, endotoxin and 1-3 β Glucan during various operational practices in the composting process. Personal samples were collected and the inhalable and respirable dust fractions were determined by gravimetric analysis. Endotoxin concentrations were determined using a Limulus Amebocyte Lysate assay (LAL). 1-3 β Glucan levels were estimated using a specific blocking agent to establish the contribution that these compounds gave to the original endotoxin assay. Employees' exposure to dust was found to be generally lower than the levels stipulated in the Control of Substances Hazardous to Health Regulations (COSHH) 2002 (as amended), (median inhalable fraction 1.08 mg/m3, min 0.25 mg/m3 max 10.80 mg/m3, median respirable fraction 0.05 mg/m3, min 0.02 mg/m3, max 1.49 mg/m3). Determination of the biological component of the dust showed that employees' exposures to endotoxin were elevated (median 31.5 EU/m3, min 2.00 EU/m3, max 1741.78 EU/m3), particularly when waste was agitated (median 175.0 EU/m3, min 2.03 EU/m3, max 1741.78 EU/m3). Eight out of 32 (25%) of the personal exposure data for endotoxin exceeded the 200 EU/m3 temporary legal limit adopted in the Netherlands and thirteen out of 32 (40.6%) exceeded the suggested 50 EU/m3 guidance level suggested to protect workers from respiratory health effects. A significant correlation was observed between employee inhalable dust exposure and personal endotoxin concentration (r = 0.728, p<0.05) and also personal endotoxin exposure and 1-3 β Glucan concentration (r = 0.817, p<0.05). Further work is needed to explore the possibility of using inhalable dust concentration as a predictor for personal endotoxin exposure. The general dust levels stipulated in the COSHH Regulations 2002 (as amended) are inadequate for

  9. Interstellar Dust - A Review

    NASA Technical Reports Server (NTRS)

    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.

  10. A new analysis of Galileo dust data near Jupiter

    NASA Astrophysics Data System (ADS)

    Soja, R. H.; Hamilton, D. P.; Altobelli, N.

    2015-05-01

    The Galileo Dust Detection System (DDS) detected a population of micron-sized grains in and amongst the orbits of Io, Europa, Ganymede and Callisto. Previous studies, using roughly 50% of the data now available, concluded that the dominant sources for the impacts were magnetospherically captured interplanetary particles largely on retrograde orbits (Colwell et al., 1998b; Thiessenhusen et al., 2000) and impact-generated ejecta from the Galilean satellites (Krüger et al., 1999b; Krivov et al., 2002a). Here we revisit the problem with the full data set and broaden our consideration to include four additional source populations: debris from the outer satellites, interplanetary and interstellar grains and particles accelerated outwards from Io and the jovian rings. We develop a model of detectable orbits at each Galileo position and we find that about 10% of the impact data require non-circular orbits with eccentricities greater than 0.1. In addition, ~3% of impacts require orbital solutions with eccentricities in excess of 0.7. Using the spatial distribution of particles, we are able to exclude, as dominant sources, all the additional source populations except for outer satellite particles. A study of DDS directional information demonstrates that none of the six standard sources fit the data well and thus a combination of sources is necessary. There are insufficient data to uniquely identify the relative strengths of the various contributions. However, we find an excess of large particles that is consistent with retrograde trajectories.

  11. LABORATORY GUIDELINES FOR ANALYSIS OF BIOTERRORISM SAMPLES

    EPA Science Inventory

    With advent of deaths associated with Bacillus anthracis spore contaminated mail, a worldwide need was apparent for increased laboratory capacity to safely analyze bioterrorism samples. The U.S. Department of Health and Human Services has furnished guidelines for microbiological...

  12. Dust negative ion acoustic shock waves in a dusty multi-ion plasma with positive dust charging current

    SciTech Connect

    Duha, S. S.

    2009-11-15

    Recent analysis of Mamun et al.[ Phys. Lett. A 373, 2355 (2009)], who considered electrons, light positive ions, heavy negative ions, and extremely massive (few micron size) charge fluctuating dust, has been extended by positive dust charging current, i.e., considering the charging currents for positively charged dust grains. A dusty multi-ion plasma system consisting of electrons, light positive ions, negative ions, and extremely massive (few micron size) charge fluctuating stationary dust have been considered. The electrostatic shock waves associated with negative ion dynamics and dust charge fluctuation have been investigated by employing the reductive perturbation method. It has been shown that the dust charge fluctuation is a source of dissipation and is responsible for the formation of dust negative ion acoustic (DNIA) shock structures. The basic features of such DNIA shock structures have been identified. The findings of this investigation may be useful in understanding the laboratory phenomena and space dusty plasmas.

  13. Heavy metal speciation in various grain sizes of industrially contaminated street dust using multivariate statistical analysis.

    PubMed

    Yıldırım, Gülşen; Tokalıoğlu, Şerife

    2016-02-01

    A total of 36 street dust samples were collected from the streets of the Organised Industrial District in Kayseri, Turkey. This region includes a total of 818 work places in various industrial areas. The modified BCR (the European Community Bureau of Reference) sequential extraction procedure was applied to evaluate the mobility and bioavailability of trace elements (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in street dusts of the study area. The BCR was classified into three steps: water/acid soluble fraction, reducible and oxidisable fraction. The remaining residue was dissolved by using aqua regia. The concentrations of the metals in street dust samples were determined by flame atomic absorption spectrometry. Also the effect of the different grain sizes (<38µm, 38-53µm and 53-74µm) of the 36 street dust samples on the mobility of the metals was investigated using the modified BCR procedure. The mobility sequence based on the sum of the first three phases (for <74µm grain size) was: Cd (71.3)>Cu (48.9)>Pb (42.8)=Cr (42.1)>Ni (41.4)>Zn (40.9)>Co (36.6)=Mn (36.3)>Fe (3.1). No significant difference was observed among metal partitioning for the three particle sizes. Correlation, principal component and cluster analysis were applied to identify probable natural and anthropogenic sources in the region. The principal component analysis results showed that this industrial district was influenced by traffic, industrial activities, air-borne emissions and natural sources. The accuracy of the results was checked by analysis of both the BCR-701 certified reference material and by recovery studies in street dust samples.

  14. VALIDATION GUIDELINES FOR LABORATORIES PERFORMING FORENSIC ANALYSIS OF CHEMICAL TERRORISM

    EPA Science Inventory

    The Scientific Working Group on Forensic Analysis of Chemical Terrorism (SWGFACT) has developed the following guidelines for laboratories engaged in the forensic analysis of chemical evidence associated with terrorism. This document provides a baseline framework and guidance for...

  15. Exozodiacal dust

    NASA Astrophysics Data System (ADS)

    Kuchner, Marc Jason

    Besides the sun, the most luminous feature of the solar system is a cloud of "zodiacal" dust released by asteroids and comets that pervades the region interior to the asteroid belt. Similar clouds of dust around other stars---exozodiacal clouds---may be the best tracers of the habitable zones of extra-solar planetary systems. This thesis discusses three searches for exozodiacal dust: (1) We observed six nearby main-sequence stars with the Keck telescope at 11.6 microns, correcting for atmosphere-induced wavefront aberrations and deconvolving the point spread function via classical speckle analysis. We compare our data to a simple model of the zodiacal dust in our own system based on COBE DIRBE observations and place upper limits on the density of exozodiacal dust in these systems. (2) We observed Sirius, Altair, and Procyon with the NICMOS Coronagraph on the Hubble Space Telescope to look for scattered light from exozodiacal dust and faint companions within 10 AU from these stars. (3) The planned nulling capability of the Keck Interferometer should allow it to probe the region <200 milliarcsecond from a bright star and to suppress on-axis starlight by factors of 10 -3 to reveal faint circumstellar material. We model the response of the Keck Interferometer to hypothetical exozodiacal clouds to derive detection limits that account for the effects of stellar leakage, photon noise, noise from null depth fluctuations, and the fact that the cloud's shape is not known a priori. We also discuss the interaction of dust with planets. We used the COBE DIRBE Sky and Zodi Atlas and the IRAS Sky Survey Atlas to search for dynamical signatures of three different planets in the solar system dust complex: (1) We searched the COBE DIRBE Sky and Zodi Atlas for a wake of dust trailing Mars. We compare the DIRBE images to a model Mars wake based on the empirical model of the Earth's wake as seen by the DIRBE. (2) We searched the COBE DIRRE Sky and Zodi Atlas for Tiojan dust near

  16. High Precision Oxygen Three Isotope Analysis of Wild-2 Particles and Anhydrous Chondritic Interplanetary Dust Particles

    NASA Technical Reports Server (NTRS)

    Nakashima, D.; Ushikubo, T.; Zolensky, Michael E.; Weisberg, M. K.; Joswiak, D. J.; Brownlee, D. E.; Matrajt, G.; Kita, N. T.

    2011-01-01

    One of the most important discoveries from comet Wild-2 samples was observation of crystalline silicate particles that resemble chondrules and CAIs in carbonaceous chondrites. Previous oxygen isotope analyses of crystalline silicate terminal particles showed heterogeneous oxygen isotope ratios with delta(sup 18)O to approx. delta(sup 17)O down to -50% in the CAI-like particle Inti, a relict olivine grain in Gozen-sama, and an olivine particle. However, many Wild-2 particles as well as ferromagnesian silicates in anhydrous interplanetary dust particles (IDPs) showed Delta(sup 17)O values that cluster around -2%. In carbonaceous chondrites, chondrules seem to show two major isotope reservoirs with Delta(sup 17)O values at -5% and -2%. It was suggested that the Delta(sup 17)O = -2% is the common oxygen isotope reservoir for carbonaceous chondrite chondrules and cometary dust, from the outer asteroid belt to the Kuiper belt region. However, a larger dataset with high precision isotope analyses (+/-1-2%) is still needed to resolve the similarities or distinctions among Wild-2 particles, IDPs and chondrules in meteorites. We have made signifi-cant efforts to establish routine analyses of small particles (< or =10micronsm) at 1-2% precision using IMS-1280 at WiscSIMS laboratory. Here we report new results of high precision oxygen isotope analyses of Wild-2 particles and anhydrous chondritic IDPs, and discuss the relationship between the cometary dust and carbonaceous chondrite chondrules.

  17. CAP - JET PROPULSION LABORATORY CONTAMINATION ANALYSIS PROGRAM

    NASA Technical Reports Server (NTRS)

    Millard, J. M.

    1994-01-01

    The Jet Propulsion Laboratory Contamination Analysis Program (CAP) is a generalized transient executive analysis computer code which solves realistic mass transport problems in the free molecular flow environment. These transport problems involve mass flux from surface source emission and re-emission, venting, and engine emission. CAP solution capability allows for one-bounce mass reflections if required. CAP was developed to solve thin-film contamination problems in the free molecular flow environment, the intent being to provide a powerful analytic tool for evaluating spacecraft contamination problems. The solution procedure uses an enclosure method based on a lumped-parameter multinodal approach with mass exchange between nodes. Transient solutions are computed by the finite difference Euler method. First-order rate theory is used to represent surface emission and reemission (user care must be taken to insure the problem is appropriate for such behavior), and all surface emission and reflections are assumed diffuse. CAP does not include the effects of post-deposition chemistry or interaction with the ambient atmosphere. CAP reads in a model represented by a multiple-block data stream. CAP allows the user to edit the input data stream and stack sequential editing operations (or cases) in order to make complex changes in behavior (surface temperatures, engine start-up and shut-down, etc.) in a single run if desired. The eight data blocks which make up the input data stream consist of problem control parameters, nodal data (area, temperature, mass, etc.), engine or vent distribution factors (based upon plume definitions), geometric configuration factors (diffuse surface emission), surface capture coefficient tables, source emission rate constant tables, reemission rate constant tables, and partial node to body collapse capability (for deposition rates only). The user must generate this data stream, since neither the problem-specific geometric relationships, the

  18. LABORATORY GUIDELINES FOR ANALYSIS OF BIOTERRORISM SAMPLES

    EPA Science Inventory

    After the attack on the World Trade Center on September 11, 2002, and the subsequent deaths associated with Bacillus anthracis spore contaminated mail, a worldwide need was apparent for increased laboratory capacity to safely analyze bioterrorism samples. The U.S. Department o...

  19. The influence of dust grain porosity on the analysis of debris disc observations

    NASA Astrophysics Data System (ADS)

    Brunngräber, Robert; Wolf, Sebastian; Kirchschlager, Florian; Ertel, Steve

    2017-02-01

    Debris discs are often modelled assuming compact dust grains, but more and more evidence for the presence of porous grains is found. We aim at quantifying the systematic errors introduced when modelling debris discs composed of porous dust with a disc model assuming spherical, compact grains. We calculate the optical dust properties derived via the fast, but simple effective medium theory. The theoretical lower boundary of the size distribution - the so-called `blowout size' - is compared in the cases of compact and porous grains. Finally, we simulate observations of hypothetical debris discs with different porosities and feed them into a fitting procedure using only compact grains. The deviations of the results for compact grains from the original model based on porous grains are analysed. We find that the blowout size increases with increasing grain porosity up to a factor of 2. An analytical approximation function for the blowout size as a function of porosity and stellar luminosity is derived. The analysis of the geometrical disc set-up, when constrained by radial profiles, is barely affected by the porosity. However, the determined minimum grain size and the slope of the grain size distribution derived using compact grains are significantly overestimated. Thus, the unexpectedly high ratio of minimum grain size to blowout size found by previous studies using compact grains can be partially described by dust grain porosity, although the effect is not strong enough to completely explain the trend.

  20. Thermodynamic analysis of the selective chlorination of electric arc furnace dust.

    PubMed

    Pickles, C A

    2009-07-30

    The remelting of automobile scrap in an electric arc furnace (EAF) results in the production of a dust, which contains high concentrations of the oxides of zinc, iron, calcium and other metals. Typically, the lead and zinc are of commercial value, while the other metals are not worth recovering. At the present time, EAF dusts are treated in high temperature Waelz rotary kiln-type processes, where the lead and zinc oxides are selectively reduced and simultaneously reoxidized and a crude zinc oxide is produced. Another alternative processing route is selective chlorination, in which the non-ferrous metals are preferentially chlorinated to their gaseous chlorides and in this manner separated from the iron. In the present research, a detailed thermodynamic analysis of this chlorination process has been performed and the following factors were investigated; temperature, amount of chlorine, lime content, silica content, presence of an inert gas and the oxygen potential. High lead and zinc recoveries as gaseous chlorides could be achieved but some of the iron oxide was also chlorinated. Additionally, the calcium oxide in the dust consumes chlorine, but this can be minimized by adding silica, which results in the formation of stable calcium silicates. The optimum conditions were determined for a typical dust composition. The selectivities achieved with chlorination were lower than those for reduction, as reported in the literature, but there are other advantages such as the potential recovery of copper.

  1. Laboratory-generated mixtures of mineral dust particles with biological substances: characterization of the particle mixing state and immersion freezing behavior

    NASA Astrophysics Data System (ADS)

    Augustin-Bauditz, Stefanie; Wex, Heike; Denjean, Cyrielle; Hartmann, Susan; Schneider, Johannes; Schmidt, Susann; Ebert, Martin; Stratmann, Frank

    2016-05-01

    Biological particles such as bacteria, fungal spores or pollen are known to be efficient ice nucleating particles. Their ability to nucleate ice is due to ice nucleation active macromolecules (INMs). It has been suggested that these INMs maintain their nucleating ability even when they are separated from their original carriers. This opens the possibility of an accumulation of such INMs in soils, resulting in an internal mixture of mineral dust and INMs. If particles from such soils which contain biological INMs are then dispersed into the atmosphere due to wind erosion or agricultural processes, they could induce ice nucleation at temperatures typical for biological substances, i.e., above -20 up to almost 0 °C, while they might be characterized as mineral dust particles due to a possibly low content of biological material. We conducted a study within the research unit INUIT (Ice Nucleation research UnIT), where we investigated the ice nucleation behavior of mineral dust particles internally mixed with INM. Specifically, we mixed a pure mineral dust sample (illite-NX) with ice active biological material (birch pollen washing water) and quantified the immersion freezing behavior of the resulting particles utilizing the Leipzig Aerosol Cloud Interaction Simulator (LACIS). A very important topic concerning the investigations presented here as well as for atmospheric application is the characterization of the mixing state of aerosol particles. In the present study we used different methods like single-particle aerosol mass spectrometry, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDX), and a Volatility-Hygroscopicity Tandem Differential Mobility Analyser (VH-TDMA) to investigate the mixing state of our generated aerosol. Not all applied methods performed similarly well in detecting small amounts of biological material on the mineral dust particles. Measuring the hygroscopicity/volatility of the mixed particles with the VH-TDMA was the most

  2. Further Analysis on the Mystery of the Surveyor III Dust Deposits

    NASA Technical Reports Server (NTRS)

    Metzger, Philip; Hintze, Paul; Trigwell, Steven; Lane, John

    2012-01-01

    The Apollo 12 lunar module (LM) landing near the Surveyor III spacecraft at the end of 1969 has remained the primary experimental verification of the predicted physics of plume ejecta effects from a rocket engine interacting with the surface of the moon. This was made possible by the return of the Surveyor III camera housing by the Apollo 12 astronauts, allowing detailed analysis of the composition of dust deposited by the LM plume. It was soon realized after the initial analysis of the camera housing that the LM plume tended to remove more dust than it had deposited. In the present study, coupons from the camera housing have been reexamined. In addition, plume effects recorded in landing videos from each Apollo mission have been studied for possible clues.

  3. Non-PBDE halogenated flame retardants in Canadian indoor house dust: sampling, analysis, and occurrence.

    PubMed

    Fan, Xinghua; Kubwabo, Cariton; Rasmussen, Pat E; Wu, Fang

    2016-04-01

    An analytical method was developed for the measurement of 18 novel halogenated flame retardants in house dust. Sample preparation was based on ultrasound-assisted solvent extraction and clean up with solid phase extraction (SPE). Sample extracts were analyzed by gas chromatography-mass spectrometry (GC/MS) operated in electron capture negative ion (ECNI) chemical ionization mode. Baseline data from 351 fresh (active) dust samples collected under the Canadian House Dust Study (CHDS) revealed that five out of 18 target chemicals were present with detection frequencies higher than 90 %. Median (range) concentrations for these five compounds were as follows: 104 (<1.5-13,000) ng/g for 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EHTBB), 8.5 (<1.7-2390) ng/g for 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), 10.2 (<1.7-430) ng/g for hexabromobenzene (HBB), 2.9 (<1.2-1410) ng/g for syn-dechlorane plus (syn-DP) and 5.6 (<1.9-1570) ng/g for anti-dechlorane plus (anti-DP). A comparison of two sampling methods in a subset of 40 homes showed significant positive correlations between samples of "active" dust and samples taken directly from the household vacuum cleaner for all target compounds having median values above their corresponding method detection limits (MDLs). In addition, the method was also applied to the analysis of the targeted compounds in National Institute of Standards and Technology (NIST) standard reference material (SRM 2585, organic contaminants in house dust). Results from the current study could contribute to the potential certification of target chemicals in SRM 2585.

  4. Analysis of dust in the coma of comet 67P using VIRTIS-M observations

    NASA Astrophysics Data System (ADS)

    Rinaldi, G.; Tozzi, G. P.; Fink, U.; Doose, L.; Capaccioni, F.; Filacchione, G.; Bockelée-Morvan, D.; Leyrat, C.; Piccioni, G.; Blecka, M.; Ciarniello, M.; Irwin, P.; Combi, M.; Palomba, E.; Migliorini, A.; Capria, M. T.; Faggi, S.; Tosi, F.

    2015-10-01

    We present a preliminary overview of the analysis on the dust spectrophotometry in the inner coma of comet 67/P that was obtained during the escort phase (started on December 2014) with the imaging spectrometer VIRTIS-M onboard the Rosetta mission [1]. The morphology and behavior of the dust coma has been monitored by VIRTIS-M from the arrival at the comet (~August 2014) throughout the early escort phase. The data reveal intricate details and numerous radial jets coming from different regions on the surface. On March 15, 2015, VIRTIS-M performed a set of 22 coma observations, each about 23 minutes in duration and offset from the nucleus by about 1 km. The 22 observations lasted about 12 hours and thus covered a complete rotation of the comet. The maps of the dust distribution in the coma reveal three major structures: a roughly uniform background dusty coma, several enhanced radiance jet features and a region that shows a thermal radiation component between 3.5 and 5.0 μm. (Figure 1 and Figure 2) The jets features can be traced back to several region of the comet, neck,body and head. We shall analyse the three major structures to provide the basis to understand coma composition and properties and the relation between gas and dust. We will discuss the morphology of the background coma, the jet and the enhanced thermal radiation. We will also examine correlations between the water vapor column density and the coma/ jet /thermal radiation intensity. For the thermal radiation component there are several explanations, viz: stray instrumental scattered light or instrumental ghosts from heated part of the nucleus, or thermal rad iation emanating from the nucleus and scattered by the dust in closest proximity or a region of small particles in the coma heated by solar radiation.

  5. Newly developed techniques for the analysis of micrometer-sized interplanetary dust particles and comet grains

    NASA Astrophysics Data System (ADS)

    Bradley, J. P.

    1991-04-01

    Electron transparent sections (30-100 nm thick) of interplanetary dust particles and other fine-grained meteoric materials are produced using an ultramicrotome equipped with a diamond knife. An analytical electron microscope (AEM) is employed to examine indigenous physical properties (e.g., porosity), mineralogy, and petrography. Large data sets of quantitative point count analysis obtained from thin sections enable direct mineralogical comparison of IDPs and Halley.

  6. Dust control effectiveness of drywall sanding tools.

    PubMed

    Young-Corbett, Deborah E; Nussbaum, Maury A

    2009-07-01

    In this laboratory study, four drywall sanding tools were evaluated in terms of dust generation rates in the respirable and thoracic size classes. In a repeated measures study design, 16 participants performed simulated drywall finishing tasks with each of four tools: (1) ventilated sander, (2) pole sander, (3) block sander, and (4) wet sponge. Dependent variables of interest were thoracic and respirable breathing zone dust concentrations. Analysis by Friedman's Test revealed that the ventilated drywall sanding tool produced significantly less dust, of both size classes, than did the other three tools. The pole and wet sanders produced significantly less dust of both size classes than did the block sander. The block sander, the most commonly used tool in drywall finishing operations, produced significantly more dust of both size classes than did the other three tools. When compared with the block sander, the other tools offer substantial dust reduction. The ventilated tool reduced respirable concentrations by 88% and thoracic concentrations by 85%. The pole sander reduced respirable concentrations by 58% and thoracic by 50%. The wet sander produced reductions of 60% and 47% in the respirable and thoracic classes, respectively. Wet sponge sanders and pole sanders are effective at reducing breathing-zone dust concentrations; however, based on its superior dust control effectiveness, the ventilated sander is the recommended tool for drywall finishing operations.

  7. Connecting laboratory behavior to field function through stable isotope analysis

    PubMed Central

    Larson, Eric R.; Pangle, Kevin L.

    2016-01-01

    Inherent difficulties of tracking and observing organisms in the field often leave researchers with no choice but to conduct behavioral experiments under laboratory settings. However, results of laboratory experiments do not always translate accurately to natural conditions. A fundamental challenge in ecology is therefore to scale up from small area and short-duration laboratory experiments to large areas and long durations over which ecological processes generally operate. In this study, we propose that stable isotope analysis may be a tool that can link laboratory behavioral observations to past field interactions or function of individual organisms. We conducted laboratory behavioral assays to measure dominance of invasive rusty crayfish, Orconectes rusticus, and used stable isotope analysis to hindcast trophic positions of these crayfish under preceding natural conditions. We hypothesized that more dominant crayfish in our assays would have higher trophic positions if dominance were related to competitive ability or willingness to pursue high-risk, high-reward prey. We did not find a relationship between crayfish dominance and trophic position, and therefore infer that laboratory dominance of crayfish may not necessarily relate to their ecology in the field. However, this is to our knowledge the first attempt to directly relate laboratory behavior to field performance via stable isotope analysis. We encourage future studies to continue to explore a possible link between laboratory and field behavior via stable isotope analysis, and propose several avenues to do so. PMID:27077010

  8. Connecting laboratory behavior to field function through stable isotope analysis.

    PubMed

    Glon, Mael G; Larson, Eric R; Pangle, Kevin L

    2016-01-01

    Inherent difficulties of tracking and observing organisms in the field often leave researchers with no choice but to conduct behavioral experiments under laboratory settings. However, results of laboratory experiments do not always translate accurately to natural conditions. A fundamental challenge in ecology is therefore to scale up from small area and short-duration laboratory experiments to large areas and long durations over which ecological processes generally operate. In this study, we propose that stable isotope analysis may be a tool that can link laboratory behavioral observations to past field interactions or function of individual organisms. We conducted laboratory behavioral assays to measure dominance of invasive rusty crayfish, Orconectes rusticus, and used stable isotope analysis to hindcast trophic positions of these crayfish under preceding natural conditions. We hypothesized that more dominant crayfish in our assays would have higher trophic positions if dominance were related to competitive ability or willingness to pursue high-risk, high-reward prey. We did not find a relationship between crayfish dominance and trophic position, and therefore infer that laboratory dominance of crayfish may not necessarily relate to their ecology in the field. However, this is to our knowledge the first attempt to directly relate laboratory behavior to field performance via stable isotope analysis. We encourage future studies to continue to explore a possible link between laboratory and field behavior via stable isotope analysis, and propose several avenues to do so.

  9. Analysis and Test Support for Phillips Laboratory Precision Structures

    DTIC Science & Technology

    1998-11-01

    Air Force Research Laboratory ( AFRL ), Phillips Research Site . Task objectives centered...around analysis and structural dynamic test support on experiments within the Space Vehicles Directorate at Kirtland Air Force Base. These efforts help...support for Phillips Laboratory Precision Structures." Mr. James Goodding of CSA Engineering was the principal investigator for this task. Mr.

  10. 2. VIEW IN ROOM 111, ATOMIC ABSORPTION BERYLLIUM ANALYSIS LABORATORY. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. VIEW IN ROOM 111, ATOMIC ABSORPTION BERYLLIUM ANALYSIS LABORATORY. AIR FILTERS AND SWIPES ARE DISSOLVED WITH ACIDS AND THE REMAINING RESIDUES ARE SUSPENDED IN NITRIC ACID SOLUTION. THE SOLUTION IS PROCESSED THROUGH THE ATOMIC ABSORPTION SPECTROPHOTOMETER TO DETECT THE PRESENCE AND LEVELS OF BERYLLIUM. - Rocky Flats Plant, Health Physics Laboratory, On Central Avenue between Third & Fourth Streets, Golden, Jefferson County, CO

  11. Using Dust from Asteroids as Regolith Microsamples

    NASA Technical Reports Server (NTRS)

    Cohen, Barbara; Chabot, Nancy; Klima, Rachel; Ernst, Carolyn; Rivkin, Andy; Postberg, Frank; Sternovsky, Zoltan

    2015-01-01

    More robust links need to be forged between meteorites and their parent bodies to understand the composition, diversity and distribution of the asteroids. A major link can be sample analysis of the parent body material and comparison with meteorite data. Dust is present around all airless bodies, generated by micrometeorite impact into their airless surfaces, which in turn lofts regolith particles into a "cloud" around the body. The composition, flux, and size distribution of dust particles can provide insight into the geologic evolution of airless bodies. For example, the Cassini Cosmic Dust Analyzer detected salts and minerals emitted by plumes at Enceladus, evidence for a subsurface ocean with a silicate seafloor. Dust analysis instruments may enable future missions to obtain elemental, isotopic and mineralogical composition of regolith particles without returning the samples to terrestrial laboratories.

  12. Properties and interactions of interplanetary dust; Proceedings of the Eighty-fifth Colloquium, Marseille, France, July 9-12, 1984

    NASA Astrophysics Data System (ADS)

    Giese, R. H.; Lamy, P.

    The conference presents papers on zodiacal light and F-coronal observations as well as space, ground, laboratory and optical studies of interplanetary dust, the relationship between this dust and comets, its interactions with plasma, its dynamics and spatial distribution. Particular attention is given to ground-based observations of near ecliptic zodiacal light brightness, the change in near-ecliptic zodiacal light brightness with heliocentric distance, IRAS observations of interplanetary dust emission, and observation of the F-corona radial velocities field between 3 and 7 solar radii. Other topics include orbits of interplanetary dust particles inside 1 AU as observed by Helios, chemical and isotopic compositons of refractory elements in deep sea spherules, optical models of the three dimensional distribution of interplanetary dust, the particle-size-distribution function of cometary dust, laboratory simulation of chemical interactions of accelerated ions with dust and ice grains, and an analysis of IRAS' solar system dust bands.

  13. Dust in Planetary Systems

    NASA Astrophysics Data System (ADS)

    Krueger, H.; Graps, A.

    2007-01-01

    , analysis of the Galileo data is still ongoing. Other space missions such as Ulysses experienced its 2nd flyby at Jupiter in 2004 and the New Horizons mission Jupiter flyby is coming up. The recent years saw significant improvements of dust detection techniques. Most notably, the development of large-area mass analyzers combined with trajectory sensors has been a major step forward towards dedicated dust astronomy missions. Moving outside our solar system, with over 200 detected extrasolar planets, the dusty debris disk research is a rapidly expanding field. Dusty debris disks can serve as detailed tracers of extrasolar planetary systems. Even though the planets are obscured, they are nevertheless dynamically imprinted in the surrounding dust to provide our best clue to study solar systems like our own. Is our system dustier or rockier than the average? Is the timing of our late heavy bombardment typical? Improvements in models comparing with improving observational data for extrasolar debris disks are reaching the point to answer these questions. Significant progress has also been made in the laboratory with investigations of 'dusty' processes and material analyses of collected samples. The Scientific Organizing Committee defined the scientific content and selected the invited reviews. These proceedings contain 6 invited papers and 39 contributed papers. The papers reflect the scientific content of the meeting, covering the areas of cosmic dust research described here. Each paper was peer-reviewed. After each review, each paper was modified by the authors, accordingly. The workshop was sponsored by National Aeronautics and Space Administration, European Space Agency, Lunar and Planetary Institute and the Hawaii Institute of Geophysics and Planetology, University of Hawaii at Manoa. It is a pleasure to thank Mary Cloud and all individuals who worked so hard behind the scenes to make this workshop a success. The generous help of all manuscript reviewers is gratefully

  14. Quantitative PCR Analysis of Molds in the Dust from Homes of Asthmatic Children in North Carolina

    SciTech Connect

    Vesper, Stephen J.; McKinstry, Craig A.; Ashley, Peter; Haugland, Richard A.; Yeatts, Karin; Bradham, Karen; Svendsen, Eric

    2007-07-10

    The vacuum cleaner bag (VCB) dust from the homes of 19 asthmatic children in North Carolina (NC) was analyzed by mold specific quantitative PCR. These results were compared to the analysis of the VCB dust from 157 homes in the HUD “American Healthy Home Survey” of homes in the US. The American Relative Moldiness Index (ARMI) was calculated for each of the homes. The mean and standard deviation (SD) of the ARMI values in the homes of the NC asthmatic children was 11.0 (5.3), compared to the HUD survey VCB ARMI value mean and SD of 6.6 (4.4). The median ARMI value was significantly higher(p < 0.001) in the asthmatic childrens’s homes. The molds Chaetomium globosum and Eurotium amsterdameli were the primary species in the NC homes making the ARMI values higher. Vacuum cleaner bag dust samples may be a less expensive but still useful method of home mold analysis.

  15. Quantitative PCR analysis of molds in the dust from homes of asthmatic children in North Carolina.

    PubMed

    Vesper, Stephen; McKinstry, Craig; Ashley, Peter; Haugland, Richard; Yeatts, Karin; Bradham, Karen; Svendsen, Erik

    2007-08-01

    The vacuum bag (VB) dust from the homes of 19 asthmatic children in North Carolina (NC) was analyzed by mold specific quantitative PCR. These results were compared to the analysis of the VB dust from 176 homes in the HUD, American Healthy Home Survey of homes in the US. The Environmental Relative Moldiness Index (ERMI) was calculated for each of the homes. The mean and standard deviation (SD) of the ERMI values in the homes of the NC asthmatic children was 16.4 (6.77), compared to the HUD survey VB ERMI value mean and SD of 11.2 (6.72), and was significantly greater (t-test, p = 0.003) in the NC asthmatic children's homes. The molds Chaetomium globosum, Aspergillus fumigatus, and the Eurotium Group were the primary species in the NC homes of asthmatics, making the ERMI values significantly higher (p < 0.02 for each). Vacuum bag dust analysis may be a useful method for estimating the mold burden in a home.

  16. VLT spectroscopic analysis of HH 202. Implications on dust destruction and thermal inhomogeneities

    NASA Astrophysics Data System (ADS)

    Espíritu, J. N.; Peimbert, A.; Delgado-Inglada, G.; Ruiz, M. T.

    2017-04-01

    We present a long-slit spectroscopic analysis of Herbig-Haro 202 and the surrounding gas of the Orion Nebula using data from the Very Large Telescope. We determined the spatial variation of its physical conditions and chemical abundances; our results are consistent with those from previous studies albeit with improved uncertainties in some determinations. Special attention is paid to the iron (Fe) and oxygen (O) abundances, which show a peak at the brightest part of HH 202, allowing us to estimate that 57% of the dust is the destroyed; we also calculate the amount of depletion of oxygen in dust grains, which amounts to 0.126±0.024 dex. Finally we show that O abundances determined from collisionally excited lines and recombination lines are irreconcilable at the center of the shock unless thermal inhomogeneities are considered.

  17. New Developments at NASA's Instrument Synthesis and Analysis Laboratory

    NASA Technical Reports Server (NTRS)

    Wood, H. John; Herring, Ellen L.; Brown, Tammy L.

    2006-01-01

    NASA's Instrument Synthesis and Analysis Laboratory (ISAL) has developed new methods to provide an instrument study in one week's engineering time. The final product is recorded in oral presentations, models and the analyses which underlie the models.

  18. Transport Energy Impact Analysis; NREL (National Renewable Energy Laboratory)

    SciTech Connect

    Gonder, J.

    2015-05-13

    Presented at the Sustainable Transportation Energy Pathways Spring 2015 Symposium on May 13, 2015, this presentation by Jeff Gonder of the National Renewable Energy Laboratory (NREL) provides information about NREL's transportation energy impact analysis of connected and automated vehicles.

  19. Los Alamos National Laboratory transuranic database analysis

    SciTech Connect

    Christensen, D.V.; Rogers, P.S.Z.; Kosiewicz, S.T.; LeBrun, D.B.

    1997-02-01

    This paper represents an overview of analyses conducted on the TRU database maintained by the Los Alamos National Laboratory (LANL). This evaluation was conducted to support the ``TRU Waste Workoff Strategies`` document and provides an estimation of the waste volume that potentially could be certified and ready for shipment to (WIPP) in April of 1998. Criteria defined in the WIPP WAC, including container type, weight limits, plutonium fissile gram equivalents and decay heat, were used to evaluated the waste for compliance. LANL evaluated the containers by facility and by waste stream to determining the most efficient plan for characterization and certification of the waste. Evaluation of the waste presently in storage suggested that 40- 60% potentially meets the WIPP WAC Rev. 5 criteria.

  20. Tokamak dust in ITER -- Safety issues and R and D supporting dust limits

    SciTech Connect

    McCarthy, K.A.; Petti, D.A.; Carmack, W.J.; Gorman, S.V.

    1998-07-01

    Tokamak dust is an important contributor to the source term in ITER safety analyses. In this paper the authors present results of R and D at the INEEL to characterize tokamak dust, and which has been used to set safety limits on dust for ITER. They present the results of analysis of particulate collected from three operating tokamaks: DIII-D at General Atomics, TFTR at Princeton Plasma Physics Laboratory, and Alcator C-MOD at Massachusetts Institute of Technology, and analysis of particulate produced in SIRENS, a disruption simulator at North Carolina State University. Analyses done include characterization of particulate to produce particle size distributions, chemical analysis, and measurement of effective surface area. The safety limits on dust in ITER have evolved during the EDA as more data have become available. The safety limits specified in NSSR-2 envelope the majority of the data, and provide conservatism to account for the uncertainty in extrapolation of the data to ITER.

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

    NASA Astrophysics Data System (ADS)

    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.

  2. Carbon in comet dust

    NASA Technical Reports Server (NTRS)

    Brownlee, D. E.

    1990-01-01

    The association of Halley particle results with data from existing meteoritic materials that can be analyzed in the laboratory is discussed. Comet samples must exist in present collections of meteoritic materials and the Halley results provide clues for identifying them. Although it is not presently possible to positively identify cometary meteorites or cometary interplanetary dust (IDP) samples, it is possible to determine which materials are similar to Halley dust and which ones are distinctly unlike Halley. The properties of these existing Halley-compatible samples provide insight into the possible properties of cometary material. Positive identification of meteoritic comet samples or direct samples returned from a comet nucleus would of course revolutionize our ability to study carbonaceous matter in comets. Modern analytical techniques are very powerful and it is possible to perform elemental, chemical, mineralogical and even limited isotopic analysis on micron-size particles. There is an important synergism between the laboratory studies of collected samples and astronomical data from comets and interstellar grains. To fully interpret results there must be convincing methods for associating a particular class or classes of meteoritic material with comets. Ultimately this will be done by direct comet sample return such as the Rosetta mission under development by ESA. At the present time the only links that can be made involve comparison with sample properties and measurable properties of comets. Unfortunately there is at present no known unique property of cometary dust that allows its absolute identification in the laboratory. The results from Halley encounters and observation do provide much new information on cometary grains. The Halley grain compositions, density, size distribution and scattering properties all provide a basis for future investigations. Other Halley properties such as the presence of polyoxymethylene and the 3.4um emission feature could

  3. Automating the analytical laboratory via the Chemical Analysis Automation paradigm

    SciTech Connect

    Hollen, R.; Rzeszutko, C.

    1997-10-01

    To address the need for standardization within the analytical chemistry laboratories of the nation, the Chemical Analysis Automation (CAA) program within the US Department of Energy, Office of Science and Technology`s Robotic Technology Development Program is developing laboratory sample analysis systems that will automate the environmental chemical laboratories. The current laboratory automation paradigm consists of islands-of-automation that do not integrate into a system architecture. Thus, today the chemist must perform most aspects of environmental analysis manually using instrumentation that generally cannot communicate with other devices in the laboratory. CAA is working towards a standardized and modular approach to laboratory automation based upon the Standard Analysis Method (SAM) architecture. Each SAM system automates a complete chemical method. The building block of a SAM is known as the Standard Laboratory Module (SLM). The SLM, either hardware or software, automates a subprotocol of an analysis method and can operate as a standalone or as a unit within a SAM. The CAA concept allows the chemist to easily assemble an automated analysis system, from sample extraction through data interpretation, using standardized SLMs without the worry of hardware or software incompatibility or the necessity of generating complicated control programs. A Task Sequence Controller (TSC) software program schedules and monitors the individual tasks to be performed by each SLM configured within a SAM. The chemist interfaces with the operation of the TSC through the Human Computer Interface (HCI), a logical, icon-driven graphical user interface. The CAA paradigm has successfully been applied in automating EPA SW-846 Methods 3541/3620/8081 for the analysis of PCBs in a soil matrix utilizing commercially available equipment in tandem with SLMs constructed by CAA.

  4. Commerce Laboratory: Mission analysis payload integration study

    NASA Technical Reports Server (NTRS)

    Bannister, T. C.

    1984-01-01

    A mission model which will accommodate commercial users and provide a basic data base for further mission planning is reported. The data bases to be developed are: (1) user requirements; (2) apparatus capabilities and availabilities; and (3) carrier capabilities. These data bases are synthesized in a trades and analysis phase along with the STS flight apparatus, and optimum missions will be identified. The completed work is reported. The user requirements data base was expanded to identify within the six scientific disciplines the areas of investigation, investigation categories and status, potential commercial application, interested parties, process, and experiment requirements. The scope of the apparatus data base was expanded to indicate apparatus status as to whether it is ground or flight equipment and, within both categories, whether the apparatus is: (1) existing, (2) under development, (3) planned, or (4) needed. Applications for the apparatus are listed. The methodology is revised in the areas of trades and analysis and mission planning. The carrier capabilities data base was updated and completed.

  5. Innovative waste stream analysis process for a utilities environmental laboratory

    SciTech Connect

    Stone, K.; Scherer, M.D.

    1997-08-01

    Compliance with government regulations for a vast multitude of chemical wastes streams can be a difficult undertaking. Under 40 CFR 261.11, a person who generates a solid waste must first determine if the waste is a hazardous waste to determine proper disposal. A common sense approach to meeting this requirement for a utility environmental laboratory has been developed at the Colorado Springs Utilities, Department of Water Resources, Environmental Quality Laboratory (EQL). The Colorado Springs Utilities, Water Resources Department, Environmental Quality Laboratory (EQL) operates a 10,000 square foot state-of-the-art laboratory facility. The EQL is a complete utilities environmental laboratory that conducts compliance analyses, process control analyses, and general environmental analyses. The EQL also provides inter-departmental analytical support analyses including polychlorinated biphenyl (PCB) transformer gas analysis for the electric department, hazard analyses for the Fire Department`s Haz-mat Unit, and compressor oil analyses for the Gas Department. The EQL has an excellent record of quality performance and is the only municipally owned laboratory in Colorado with Class 100 Clean Room capability. The EQL developed an innovative waste stream analysis process for its laboratory operations.

  6. Dust mobilization on airless planetary bodies

    NASA Astrophysics Data System (ADS)

    Horanyi, M.

    2013-12-01

    There are a number of observations indicating that small dust grains can be mobilized and transported on the surfaces of airless bodies. While not a single measurement to date can unambiguously identify the responsible process, the entire body of existing observations as a whole suggests that electrodynamics remains the most likely candidate. If this is the case, our models have to be able to account for the electrostatic charging and subsequent dynamics of the grains sculpted by surface electric fields. The Colorado Center for Dust and Atmospheric Studies (CCLDAS) of the former NASA Lunar Science Institute conducted a series of small-scale laboratory experiments to address dust charging and mobilization issues, including the effects of flowing plasmas and UV radiation. This talk will draw conclusions based on these series of experiments and use them to guide the analysis and interpretation of the data from the Lunar Dust Experiment (LDEX) onboard the Lunar Atmosphere and Dust Environment Mission (LADEE). By the time of this talk, LADEE is expected to collect its initial science measurements. The combination of laboratory and in situ space measurements provides a unique opportunity to advance our theoretical models on the transport of charged dust particles on the lunar surface, and apply these arguments to all other airless planetary bodies.

  7. Characterization of Atmospheric Mineral Dust from Radiometric and Polarimetric Remote Sensing

    DTIC Science & Technology

    2007-09-30

    microphysical and optical properties. APPROACH Our approach combines an extensive forward modeling, analysis of laboratory and in-situ data of dust ...Characterization of Atmospheric Mineral Dust from Radiometric and Polarimetric Remote Sensing PI: Dr. Irina N. Sokolik School of Earth and...the properties of mineral aerosols and their interactions with visible and IR atmospheric radiation, and to develop the dust optical models needed

  8. Method development for analysis of urban dust using scanning electron microscopy with energy dispersive x-ray spectrometry to detect the possible presence of world trade center dust constituents

    USGS Publications Warehouse

    Bern, A.M.; Lowers, H.A.; Meeker, G.P.; Rosati, J.A.

    2009-01-01

    The collapse of the World Trade Center Towers on September 11, 2001, sent dust and debris across much of Manhattan and in the surrounding areas. Indoor and outdoor dust samples were collected and characterized by U.S. Geological Survey (USGS) scientists using scanning electron microscopy with energy-dispersive spectrometry (SEM/EDS). From this characterization, the U.S. Environmental Protection Agency and USGS developed a particulate screening method to determine the presence of residual World Trade Center dust in the indoor environment using slag wool as a primary "signature". The method describes a procedure that includes splitting, ashing, and sieving of collected dust. From one split, a 10 mg/mL dust/ isopropanol suspension was prepared and 10-30 ??L aliquots of the suspension placed on an SEM substrate. Analyses were performed using SEM/EDS manual point counting for slag wool fibers. Poisson regression was used to identify some of the sources of uncertainty, which are directly related to the small number of fibers present on each sample stub. Preliminary results indicate that the procedure is promising for screening urban background dust for the presence of WTC dust. Consistent sample preparation of reference materials and samples must be performed by each laboratory wishing to use this method to obtain meaningful and accurate results. ?? 2009 American Chemical Society.

  9. Method development for analysis of urban dust using scanning electron microscopy with energy dispersive X-ray spectrometry to detect the possible presence of World Trade Center dust constituents.

    PubMed

    Bern, Amy M; Lowers, Heather A; Meeker, Gregory P; Rosati, Jacky A

    2009-03-01

    The collapse of the World Trade Center Towers on September 11, 2001, sent dust and debris across much of Manhattan and in the surrounding areas. Indoor and outdoor dust samples were collected and characterized by U.S. Geological Survey (USGS) scientists using scanning electron microscopy with energy-dispersive spectrometry (SEM/EDS). From this characterization, the U.S. Environmental Protection Agency and USGS developed a particulate screening method to determine the presence of residual World Trade Center dust in the indoor environment using slag wool as a primary "signature". The method describes a procedure that includes splitting, ashing, and sieving of collected dust From one split, a 10 mg/mL dust/isopropanol suspension was prepared and 10-30 microL aliquots of the suspension placed on an SEM substrate. Analyses were performed using SEM/EDS manual point counting for slag wool fibers. Poisson regression was used to identify some of the sources of uncertainty, which are directly related to the small number of fibers present on each sample stub. Preliminary results indicate that the procedure is promising for screening urban background dust for the presence of WTC dust. Consistent sample preparation of reference materials and samples must be performed by each laboratory wishing to use this method to obtain meaningful and accurate results.

  10. Quantitative detection of mass concentration of sand-dust storms via wind-profiling radar and analysis of Z-M relationship

    NASA Astrophysics Data System (ADS)

    Wang, Minzhong; Ming, Hu; Ruan, Zheng; Gao, Lianhui; Yang, Di

    2016-12-01

    With the aim to achieve quantitative monitoring of sand-dust storms in real time, wind-profiling radar is applied to monitor and study the process of four sand-dust storms in the Tazhong area of the Taklimakan Desert. Through evaluation and analysis of the spatial-temporal distribution of reflectivity factor, it is found that reflectivity factor ranges from 2 to 18 dBz under sand-dust storm weather. Using echo power spectrum of radar vertical beams, sand-dust particle spectrum and sand-dust mass concentration at the altitude of 600 ˜ 1500 m are retrieved. This study shows that sand-dust mass concentration reaches 700 μg/m3 under blowing sand weather, 2000 μg/m3 under sand-dust storm weather, and 400 μg/m3 under floating dust weather. The following equations are established to represent the relationship between the reflectivity factor and sand-dust mass concentration: Z = 20713.5 M 0.995 under floating dust weather, Z = 22988.3 M 1.006 under blowing sand weather, and Z = 24584.2 M 1.013 under sand-dust storm weather. The retrieval results from this paper are almost consistent with previous monitoring results achieved by former researchers; thus, it is implied that wind-profiling radar can be used as a new reference device to quantitatively monitor sand-dust storms.

  11. Restoration and Future Analysis of the Apollo Lunar Dust Detector Data

    NASA Astrophysics Data System (ADS)

    McBride, M.; Williams, D. R.; Hills, H. K.

    2012-12-01

    The Dust, Thermal and Radiation Engineering Measurement (DTREM) packages mounted on the central stations of the Apollo 11, 12, 14, and 15 ALSEPs (Apollo Lunar Surface Experiments Packages) measured the outputs of exposed solar cells and thermistors over time. The goal of the experiment, also commonly known as the dust detector, was to study the long-term effects of dust, radiation, and temperature at the lunar surface on solar cells. The original data were never archived with NASA, with the exception of 38 reels of microfilm archived at the National Space Science Data Center. These reels contained images of computer printouts of times and raw and calibrated DTREM data for Apollo 14 and 15. The high volume of data is not readily accessible in this form. The raw telemetry for the DTREM also exists as part of the ALSEP housekeeping (Word 33) telemetry. As part of the lunar data restoration effort we are converting the telemetry to digital tables containing the fully calibrated dust detector data. These restored data sets will be archived through the Lunar Data Node of the Planetary Data System (PDS) for general use by the lunar community. In this form, these data will finally be amenable to study by modern techniques not available during the Apollo era. Over the past year, analysis of the correlation between the NSSDC microfilm record and the raw telemetry was used to determine the translations and calibrations necessary to convert the digital telemetry into a fully calibrated data set giving temperatures and solar cell outputs over time. The final data set consists of a reading every 54 seconds over periods of 5 years for Apollo 14 and 15. The sheer quantity of data shows why a fully digital form is necessary for proper analysis. The Apollo 11 DTREM was designed for a short lifetime and returned less than two lunations of data. We do not currently have the translation and calibration information necessary to convert the raw telemetry to a calibrated data set for

  12. Particle atlas of World Trade Center dust

    USGS Publications Warehouse

    Lowers, Heather; Meeker, Gregory P.

    2005-01-01

    The United States Environmental Protection Agency (EPA) has begun a reassessment of the presence of World Trade Center (WTC) dust in residences, public buildings, and office spaces in New York City, New York. Background dust samples collected from residences, public buildings, and office spaces will be analyzed by multiple laboratories for the presence of WTC dust. Other laboratories are currently studying WTC dust for other purposes, such as health effects studies. To assist in inter-laboratory consistency for identification of WTC dust components, this particle atlas of phases in WTC dust has been compiled.

  13. Inertia-Centric Stability Analysis of a Planar Uniform Dust Molecular Cloud with Weak Neutral-Charged Dust Frictional Coupling

    NASA Astrophysics Data System (ADS)

    K. Karmakar, P.; Borah, B.

    2014-05-01

    This paper adopts an inertia-centric evolutionary model to study the excitation mechanism of new gravito-electrostatic eigenmode structures in a one-dimensional (1-D) planar self-gravitating dust molecular cloud (DMC) on the Jeans scale. A quasi-neutral multi-fluid consisting of warm electrons, warm ions, neutral gas and identical inertial cold dust grains with partial ionization is considered. The grain-charge is assumed not to vary at the fluctuation evolution time scale. The neutral gas particles form the background, which is weakly coupled with the collapsing grainy plasma mass. The gravitational decoupling of the background neutral particles is justifiable for a higher inertial mass of the grains with higher neutral population density so that the Jeans mode frequency becomes reasonably large. Its physical basis is the Jeans assumption of a self-gravitating uniform medium adopted for fiducially analytical simplification by neglecting the zero-order field. So, the equilibrium is justifiably treated initially as “homogeneous”. The efficacious inertial role of the thermal species amidst weak collisions of the neutral-charged grains is taken into account. A standard multiscale technique over the gravito-electrostatic equilibrium yields a unique pair of Korteweg-de Vries (KdV) equations. It is integrated numerically by the fourth-order Runge-Kutta method with multi-parameter variation for exact shape analyses. Interestingly, the model is conducive for the propagation of new conservative solitary spectral patterns. Their basic physics, parametric features and unique characteristics are discussed. The results go qualitatively in good correspondence with the earlier observations made by others. Tentative applications relevant to space and astrophysical environments are concisely highlighted.

  14. A study and analysis of the MSFC lunar roving vehicle dust profile test program

    NASA Technical Reports Server (NTRS)

    Mullis, C. H.

    1971-01-01

    The dust problem and fender design for the LRV were studied under reduced gravity with a lunar soil simulant. The test equipment, soil characteristics of the lunar soil simulant, and the test procedures are described. It is concluded: (1) The fender plus flap design is adequate. (2) Vacuum conditions tend to eliminate or reduce suspended dust clouds. (3) Reduced gravity conditions tend to increase the dust problems. (4) Slow starting speeds are necessary to minimize slip and reduce initial dust generation.

  15. Using thermal infrared (TIR) data to characterize dust sources, dust fall and the linkage to climate in the Middle East

    NASA Astrophysics Data System (ADS)

    Mohammad, R.; Ramsey, M.; Scheidt, S. P.

    2010-12-01

    Prior to mineral dust deposition affecting albedo, aerosols can have direct and indirect effects on local to regional scale climate by changing both the shortwave and longwave radiative forcing. In addition, mineral dust causes health hazards, such as respiratory-related illnesses and deaths, loss of agricultural soil, and safety hazards to aviation and motorists due to reduced visibility. Previous work utilized satellite and ground-based TIR data to describe the direct longwave radiative effect of the Saharan Air Layer (SAL) over the Atlantic Ocean originating from dust storms in the Western Sahara. TIR emission spectroscopy was used to identify the spectral absorption features of that dust. The current research focuses on Kuwait and utilizes a comprehensive set of spatial, analytical and geological tools to characterize dust emissions and its radiative effects. Surface mineral composition maps for the Kuwait region were created using ASTER images and GIS datasets in order to identify the possible sources of wind-blown dust. Backward trajectory analysis using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model suggests the dust source areas were located in Iraq, Syria, Jordan and Saudi Arabia. Samples collected from two dust storms (May and July 2010) were analyzed for their mineral composition and to validate the dust source areas identified by the modeling and remote sensing analysis. These air fall dust samples were collected in glass containers on a 13 meter high rooftop in the suburb of Rumaithiya in Kuwait. Additional samples will be collected to expand the analysis and their chemical compositions will be characterized by a combination of laboratory X-ray fluorescence (XRF), Scanning Electron Microscopy (SEM) and TIR emission spectroscopy. The overarching objective of this ongoing research is to both characterize the effects of mineral dust on climate as well as establish a predictive tool that can identify dust storm sources and

  16. A Preliminary Analysis of Cometary Dust in the 1st Year of the NEOWISE Restarted Mission

    NASA Astrophysics Data System (ADS)

    Kramer, Emily A.; Bauer, James M.; Fernández, Yanga R.; Mainzer, Amy K.; Grav, Tommy; Masiero, Joseph R.; Nugent, Carolyn R.; Sonnett, Sarah; Cutri, Roc; Stevenson, Rachel

    2015-11-01

    As some of the most pristine objects in the Solar System, comets present an opportunity to understand the mechanics and chemistry of the planetary formation era. By studying a large number of comets in different dynamical classes, we can better understand the ensemble properties of the different classes, and begin to characterize the evolution that may have occurred since their formation.In late 2013, the WISE spacecraft was brought out of hibernation, and renamed NEOWISE with a renewed goal to detect and characterize small bodies using its 3.4 and 4.6-micron bands. Survey operations began in December 2013 [1], and the first year of data was publicly released in March 2015 [2]. During the course of the first year of the restarted mission, over 60 comets were serendipitously detected by NEOWISE at heliocentric distances between ~1-7.5 AU, including 3 newly discovered comets. The comets detected were split roughly evenly between short-period and long-period comets, and many displayed extended dust structures. Several of the comets were detected multiple times over the course of the year, and some were also seen during the prime WISE mission. This long baseline allows for an intriguing analysis of long-term cometary behavior.NEOWISE has sampled the behavior of these comet dynamical sub-types over the thermal infrared and near-infrared reflected-light regimes, where effects from different particle size ranges of dust may dominate the morphologies and observed fluxes. We present a preliminary analysis of the cometary dust seen in these data, including dynamical models to constrain the sizes and ages of the dust particles. We discuss how these results compare to those obtained for the comets seen in the 12 and 22-micron WISE prime mission data.Acknowledgments: This publication makes use of data products from (1) WISE, which is a joint project of UCLA and JPL/Caltech, funded by NASA; and (2) NEOWISE, which is a project of JPL/Caltech, funded by the Planetary Science

  17. Cloning, bioinformatics analysis, and expression of the dust mite allergen Der f 5 of Dermatophagoides farinae.

    PubMed

    Cui, Yubao; Zhou, Ying; Ma, Guifang; Yang, Li; Wang, Yungang; Shi, Weihong

    2012-08-01

    Crude extracts of house dust mites are used clinically for diagnosis and immunotherapy of allergic diseases, including bronchial asthma, perennial rhinitis, and atopic dermatitis. However, crude extracts are complexes with non-allergenic antigens and lack effective concentrations of important allergens, resulting in several side effects. Dermatophagoides farinae (Hughes; Acari: Pyroglyphidae) is one of the predominant sources of dust mite allergens, which has more than 30 groups of allergen. The cDNA coding for the group 5 allergen of D. farinae from China was cloned, sequenced and expressed. According to alignment using the VECTOR NTI 9.0 software, there were eight mismatched nucleotides in five cDNA clones resulting in seven incompatible amino acid residues, suggesting that the Der f 5 allergen might have sequence polymorphism. Bioinformatics analysis revealed that the matured Der f 5 allergen has a molecular mass of 13604.03 Da, a theoretical pI of 5.43 and is probably hydrophobic and cytoplasmic. Similarities in amino acid sequences between Der f 5 and allergens of other domestic mite species, viz. Der p 5, Blo t 5, Sui m 5, and Lep d 5, were 79, 48, 53, and 37%, respectively. Phylogenetic analysis indicated that Der f 5 and Der p 5 clustered together. Blo t 5 and Ale o 5 also clustered together, although Blomia tropicalis and Aleuroglyphus ovatus belong to different mite families, viz. Echimyopodidae and Acaridae, respectively.

  18. ANALYSIS OF THE INSTABILITY DUE TO GAS–DUST FRICTION IN PROTOPLANETARY DISKS

    SciTech Connect

    Shadmehri, Mohsen

    2016-02-01

    We study the stability of a dust layer in a gaseous disk subject to linear axisymmetric perturbations. Instead of considering single-size particles, however, the population of dust particles is assumed to consist of two grain species. Dust grains exchange momentum with the gas via the drag force and their self-gravity is also considered. We show that the presence of two grain sizes can increase the efficiency of the linear growth of drag-driven instability in the protoplanetary disks (PPDs). A second dust phase with a small mass, compared to the first dust phase, would reduce the growth timescale by a factor of two or more, especially when its coupling to the gas is weak. This means that once a certain amount of large dust particles form, even though it is much smaller than that of small dust particles, the dust layer becomes more unstable and dust clumping is accelerated. Thus, the presence of dust particles of various sizes must be considered in studies of dust clumping in PPDs where both large and small dust grains are present.

  19. Dust Storm Forecasting for Al Udeid AB, Qatar: An Empirical Analysis

    DTIC Science & Technology

    2004-03-01

    DUST STORM FORECASTING FOR AL UDEID AB, QATAR: AN...Department of Defense, or the United States Government. vi AFIT/GM/ENP-04-01 DUST STORM ...APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED vii iv AFIT/GM/ENP-04-01 Abstract Dust storms are extreme weather events

  20. Analysis of Cometary Dust Impact Residues in the Aluminum Foil Craters of Stardust

    NASA Technical Reports Server (NTRS)

    Graham, G. A.; Kearsley, A. T.; Vicenzi, E. P.; Teslich, N.; Dai, Z. R.; Rost, D.; Horz, F.; Bradley, J. P.

    2007-01-01

    In January 2006, the sample return capsule from NASA s Stardust spacecraft successfully returned to Earth after its seven year mission to comet Wild-2. While the principal capture medium for comet dust was low-density graded silica aerogel, the 1100 series aluminum foil (approximately 100 m thick) which wrapped around the T6064 aluminum frame of the sample tray assembly (STA) contains micro-craters that constitute an additional repository for Wild-2 dust. Previous studies of similar craters on spacecraft surfaces, e.g. the Long Duration Exposure Facility (LDEF), have shown that impactor material can be preserved for elemental and mineralogical characterization, although the quantity of impact residue in Stardust craters far exceeds previous missions. The degree of shock-induced alteration experienced by the Wild-2 particles impacting on foil will generally be greater than for those captured in the low-density aerogel. However, even some of the residues found in LDEF craters showed not only survival of crystalline silicates but even their solar flare tracks, which are extremely fragile structures and anneal at around 600 C. Laboratory hypervelocity experiments, using analogues of Wild-2 particles accelerated into flight-grade foils under conditions close to those of the actual encounter, showed retention of abundant projectile residues at the Stardust encounter velocity of 6.1 km/s. During the preliminary examination (PE) of the returned foils, using optical and electron microscopy studies, a diverse range in size and morphologies of micro-craters was identified. In this abstract we consider the state of residue preservation in a diverse range of craters with respect to their elemental composition and inferred mineralogy of the original projectiles.

  1. Application of a PC analysis of remote sensing spectral reflectance data to determine source regions for dust storms.

    NASA Astrophysics Data System (ADS)

    Dickinson, R. E.; Zhou, L.; Sokolik, I.

    2006-12-01

    The source regions of deserts over which dust is lifted into the air occur on relatively small scales and hve been difficult to characterize geographically. The research programs supporting NASA's terra and aqua satellites have pioneered the development of quality controlled climatologies of surface information, that should include features characteristic of dust source regions. With quality satellite data, patterns can be distinguished that are likely to indicate real geophysical features. Zhou et al. (2005) applied a principle component (PC) analysis to the North African desert that revealed intriguing spatial structures. It represents the spatial patterns with a limited number of PC's that maximize the covariances between spectral bands averaged over space. Such analysis acts as a filter of nonphysical information and should highlight commonly occurring small scale features, some of which are likely connected to dust source regions. We present a new such analysis for the Taklamakan desert of China. The first 2 or 3 modes are removed as being of too coarse a spatial scale to represent source regions. Features of the remaining 3 or 4 patterns of significant amplitude are examined for their possible relevancy to dust uplifting. In particular, patterns that show seasonality of vegetation are deemed unlikely to be so relevant. Distinctions in the spectral patterns and MODIS BRDF kernels of remaining terms are examined for their likely indication of a dust source region.

  2. Estimation of origins of polycyclic aromatic hydrocarbons in size-fractionated road dust in Tokyo with multivariate analysis.

    PubMed

    Pengchai, P; Nakajima, F; Furumai, H

    2005-01-01

    This study aimed to estimate the origins of polycyclic aromatic hydrocarbons (PAHs) in size-fractionated road dust in Tokyo. First, seven categories of PAHs sources were defined: diesel vehicle exhaust, gasoline vehicle exhaust, tire, pavement, asphalt or bitumen, petroleum products excluding tire and asphalt, and combustion products except for those in vehicle engines. The 189 source data of 12-PAHs profiles were classified into 11 groups based on cluster analysis combined with principal component analysis. Next, 18 road dust samples were collected from eight streets in Tokyo and fractionated into four different particle-size-fractions: 0.1-45, 45-106, 106-250, and 250-2000 microm. In order to estimate the contributions of the classified source groups (S1-S11) to PAHs in the road dust, multiple regression analysis was performed with 12-PAH profile of the road dust as dependent variable and average 12-PAHs profiles of the 11 source groups as 11 explanatory variables. Diesel vehicle exhaust, tire and pavement were the major contributors of PAHs in the fractionated road dust. Although the estimated contributions of the 11 source groups varied among the particle-size-fractions, there was no clear and consistent relationship between particle size and the major PAH contributor.

  3. Polybrominated Diphenyl Ethers in Dryer Lint: An Advanced Analysis Laboratory

    ERIC Educational Resources Information Center

    Thompson, Robert Q.

    2008-01-01

    An advanced analytical chemistry laboratory experiment is described that involves environmental analysis and gas chromatography-mass spectrometry. Students analyze lint from clothes dryers for traces of flame retardant chemicals, polybrominated diphenylethers (PBDEs), compounds receiving much attention recently. In a typical experiment, ng/g…

  4. New Developments at NASA's Instrument Synthesis & Analysis Laboratory (ISAL)

    NASA Technical Reports Server (NTRS)

    Wood, H. John; Brown, Tammy L.; Herring, Ellen L.

    2006-01-01

    This viewgraph document reviews the work of NASA's Instrument Synthesis and Analysis Laboratory (ISAL). The work of the ISAL has substantially reduced the time required to develop an instrument concept. The document reviews the design process in detail and planned interaction with the end user of the instrument.

  5. Conformational Analysis in an Advanced Integrated Laboratory Course

    ERIC Educational Resources Information Center

    Ball, David B.; Miller, Randy M.

    2004-01-01

    A series of sophisticated, combined laboratory experiments are developed involving the use of various spectroscopic and other techniques in the conformational analysis of cyclohexane mechanisms. The multi-system approach enables the students to transcend the one-dimensional procedure, and develops their synthetic and diagnostic skills.

  6. Incorporating Basic Optical Microscopy in the Instrumental Analysis Laboratory

    ERIC Educational Resources Information Center

    Flowers, Paul A.

    2011-01-01

    A simple and versatile approach to incorporating basic optical microscopy in the undergraduate instrumental analysis laboratory is described. Attaching a miniature CCD spectrometer to the video port of a standard compound microscope yields a visible microspectrophotometer suitable for student investigations of fundamental spectrometry concepts,…

  7. Should precipitation influence dust emission in global dust models?

    NASA Astrophysics Data System (ADS)

    Okin, Gregory

    2016-04-01

    Soil moisture modulates the threshold shear stress required to initiate aeolian transport and dust emission. Most of the theoretical and laboratory work that has confirmed the impact of soil moisture has appropriately acknowledged that it is the soil moisture of a surface layer a few grain diameters thick that truly controls threshold shear velocity. Global and regional models of dust emission include the effect of soil moisture on transport threshold, but most ignore the fact that only the moisture of the very topmost "active layer" matters. The soil moisture in the active layer can differ greatly from that integrated through the top 2, 5, 10, or 100 cm (surface layers used by various global models) because the top 2 mm of heavy texture soils dries within ~1/2 day while sandy soils dry within less than 2 hours. Thus, in drylands where dust emission occurs, it is likely that this top layer is drier than the underlying soil in the days and weeks after rain. This paper explores, globally, the time between rain events in relation to the time for the active layer to dry and the timing of high wind events. This analysis is carried out using the same coarse reanalyses used in global dust models and is intended to inform the soil moisture controls in these models. The results of this analysis indicate that the timing between events is, in almost all dust-producing areas, significantly longer than the drying time of the active layer, even when considering soil texture differences. Further, the analysis shows that the probability of a high wind event during the period after a rain where the surface is wet is small. Therefore, in coarse global models, there is little reason to include rain-derived soil moisture in the modeling scheme.

  8. Analysis of metals in cement kiln dust using the lithium fusion method

    SciTech Connect

    Schoenberger, R.J.; Buchanan, C.E. Jr.

    1994-12-31

    The analysis of metals using hot plate, microwave and lithium borate fusion digestion has been investigated for four samples cement kiln dust. Results of analysis show that the standard hot plate digestion yields the lowest results or recovery of metals. Microwave digestion generally shows a slightly higher recovery of metals, but the significance of the difference can not be calculated until more samples are analyzed. Because of the presence of silica and alumina, the fusion method shows significantly higher recovery for chromium, nickel, zinc, potassium, calcium, and iron. The fusion vaporizes some constituents; lead, sulfur, vanadium and therefore the method is not usable for those constituents. The impact on cadmium is unclear and more investigation is needed.

  9. Mixing state of aerosols and direct observation of carbonaceous and marine coatings on African dust by individual particle analysis

    NASA Astrophysics Data System (ADS)

    Deboudt, Karine; Flament, Pascal; ChoëL, Marie; Gloter, Alexandre; Sobanska, Sophie; Colliex, Christian

    2010-12-01

    The mixing state of aerosols collected at M'Bour, Senegal, during the Special Observing Period conducted in January-February 2006 (SOP-0) of the African Monsoon Multidisciplinary Analysis project (AMMA), was studied by individual particle analysis. The sampling location on the Atlantic coast is particularly adapted for studying the mixing state of tropospheric aerosols since it is (1) located on the path of Saharan dust plumes transported westward over the northern tropical Atlantic, (2) influenced by biomass burning events particularly frequent from December to March, and (3) strongly influenced by anthropogenic emissions from polluted African cities. Particle size, morphology, and chemical composition were determined for 12,672 particles using scanning electron microscopy (automated SEM-EDX). Complementary analyses were performed using transmission electron microscopy combined with electron energy loss spectrometry (TEM-EELS) and Raman microspectrometry. Mineral dust and carbonaceous and marine compounds were predominantly found externally mixed, i.e., not present together in the same particles. Binary internally mixed particles, i.e., dust/carbonaceous, carbonaceous/marine, and dust/marine mixtures, accounted for a significant fraction of analyzed particles (from 10.5% to 46.5%). Western Sahara was identified as the main source of mineral dust. Two major types of carbonaceous particles were identified: "tar balls" probably coming from biomass burning emissions and soot from anthropogenic emissions. Regarding binary internally mixed particles, marine and carbonaceous compounds generally formed a coating on mineral dust particles. The carbonaceous coating observed at the particle scale on African dust was evidenced by the combined use of elemental and molecular microanalysis techniques, with the identification of an amorphous rather than crystallized carbon structure.

  10. Trajectory analysis for the nucleus and dust of comet C/2013 A1 (Siding Spring)

    SciTech Connect

    Farnocchia, Davide; Chesley, Steven R.; Chodas, Paul W.; Tricarico, Pasquale; Kelley, Michael S. P.; Farnham, Tony L.

    2014-08-01

    Comet C/2013 A1 (Siding Spring) will experience a high velocity encounter with Mars on 2014 October 19 at a distance of 135,000 km ± 5000 km from the planet center. We present a comprehensive analysis of the trajectory of both the comet nucleus and the dust tail. The nucleus of C/2013 A1 cannot impact on Mars even in the case of unexpectedly large nongravitational perturbations. Furthermore, we compute the required ejection velocities for the dust grains of the tail to reach Mars as a function of particle radius and density and heliocentric distance of the ejection. A comparison between our results and the most current modeling of the ejection velocities suggests that impacts are possible only for millimeter to centimeter size particles released more than 13 AU from the Sun. However, this level of cometary activity that far from the Sun is considered extremely unlikely. The arrival time of these particles spans a 20-minute time interval centered at 2014 October 19 at 20:09 TDB, i.e., around the time that Mars crosses the orbital plane of C/2013 A1. Ejection velocities larger than currently estimated by a factor >2 would allow impacts for smaller particles ejected as close as 3 AU from the Sun. These particles would reach Mars from 19:13 TDB to 20:40 TDB.

  11. Analysis of TES FFSM Eddies and MOC Dust Storms, MY 24 - 26

    NASA Astrophysics Data System (ADS)

    Noble, J.; Wilson, R.; Haberle, R. M.; Bridger, A. F.; Hollingsworth, J. L.; Kahre, M. A.; Barnes, J.; Cantor, B. A.

    2013-12-01

    Mars Global Surveyor (MGS) orbiter observed a planet-encircling dust storm (PDS) in Mars year (MY) 25 from Ls=176.2-263.4°. We present an examination of Mars Orbiter Camera (MOC) dust storms and transient baroclinic eddies identified from Fast Fourier Synoptic Mapping (FFSM) of Thermal Emission Spectrometer (TES) temperatures for the first two phases of the storm: precursor, Ls=176.2- 184.7°, and expansion, Ls=184.7-193°. FFSM analysis of TES 3.7 hPa thermal data shows the presence of eastward traveling waves at 60° S with a period of about three sols. We hypothesize that these waves are transient baroclinic eddies that contributed to the initiation of precursor storms near Hellas. Integration of FFSM and MOC MY 24 and 25 data shows interesting temporal and spatial associations between the evolution of eddies and storms, including: 1) comparable periodicities of travelling waves and pulses of storm activity; 2) concurrent eastward propagation of both eddies and storms; and 3) structured spatial relationship where high-latitude storms tend to occur on the eastern side of the eddy, while lower (and some middle) latitude storms occur on the western. These results suggest a causal relationship between baroclinic eddies and local storm initiation. New MY 26 results will be presented.

  12. Analysis of TES FFSM Eddies and MOC Dust Storms, MY 24 - 26

    NASA Astrophysics Data System (ADS)

    Noble, J.; Haberle, R. M.; Bridger, A. F.; Wilson, R.; Barnes, J.; Hollingsworth, J.; Kahre, M. A.; Cantor, B. A.

    2012-12-01

    Mars Global Surveyor (MGS) orbiter observed a planet-encircling dust storm (PDS) in Mars year (MY) 25 from Ls=176.2-263.4°. We present an examination of Mars Orbiter Camera (MOC) dust storms and transient baroclinic eddies identified from Fast Fourier Synoptic Mapping (FFSM) of Thermal Emission Spectrometer (TES) temperatures for the first two phases of the storm: precursor, Ls=176.2- 184.7°, and expansion, Ls=184.7-193°. FFSM analysis of TES 3.7 hPa thermal data shows the presence of eastward-traveling waves at 60° S with a period of about three sols. We hypothesize that these waves are transient baroclinic eddies that contributed to the initiation of precursor storms near Hellas. Integration of FFSM and MOC MY 24 and 25 data shows interesting temporal and spatial associations between the evolution of eddies and storms, including: 1) comparable periodicities of travelling waves and pulses of storm activity; 2) concurrent eastward propagation of both eddies and storms; and 3) structured spatial relationship where high-latitude storms tend to occur on the eastern side of the eddy, while lower (and some middle) latitude storms occur on the western. These results suggest a causal relationship between baroclinic eddies and local storm initiation. New MY 26 results will be presented.lt;img border=0 src="images/P22A-03_B.jpg">

  13. Analysis of Characteristics of Dust Aerosols in Northwest China based on Satellite Remote-sensing Data

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Liu, L.; Zhao, Y.; Gong, S.; Henze, D. K.

    2014-12-01

    Based on the CloudSat data, effects of dust aerosol on cloud parameters under the circumstance of the monthly average, dusty days and dust-free days were analyzed during April, 2010. By using L2 aerosol profiles satellite data of CALIOP/CALIOPSO the aerosol extinction coefficients were analyzed over northwest China. As an important case, space distribution and transmission route of dust aerosol were investigated during the dust events occurred from April 16th to 18th in 2013 over northwest China, based on L1 data of CALIOP/CALIOPSO, a combination of multiple satellite data and models. The results show that (1) dust aerosols could cause the reduction in effective radius of particle, cloud liquid water content and cloud optical thickness, and the increase of the number concentration of liquid cloud particles as well, (2) The aerosol extinction coefficients were decreased with the increase of height. The value of the aerosol extinction coefficients in desert area was greater than that in the area of Gansu Province due to urbanization. Distribution of the aerosol extinction coefficients in spring was nearly the same as the annual average. (3) Using aerosol products of the vertical characteristics from CALIOP/CALIOPSO, aerosol was classified during dust events, and with NAPPS Global aerosol model, daily distribution of the dust aerosol concentration was given, showing the transport and diffusion of dust aerosol. With HYSPLIT trajectory model dust transportation path of the sand dust source areas was simulated and identified. During the outbreak of dust event dust aerosol was mainly distributed over the surface about 3km, with depolarization ratio at 0.4 and color ratio at 1.2. During the dust events were close to weak and stop, dust aerosol was mainly distributed over the surface under 2 km, with depolarization ratio from 0.2 to 0.3, and color ratio about 1.

  14. Analysis of Characteristics of Dust Aerosols in Northwest China based on Satellite Remote-sensing Data

    NASA Astrophysics Data System (ADS)

    Zhang, W.; Liu, D.; Zhao, Q.

    2015-12-01

    Based on the CloudSat data, effects of dust aerosol on cloud parameters under the circumstance of the monthly average, dusty days and dust-free days were analyzed during April, 2010. By using L2 aerosol profiles satellite data of CALIOP/CALIOPSO the aerosol extinction coefficients were analyzed over northwest China. As an important case, space distribution and transmission route of dust aerosol were investigated during the dust events occurred from April 16th to 18th in 2013 over northwest China, based on L1 data of CALIOP/CALIOPSO, a combination of multiple satellite data and models. The results show that (1) dust aerosols could cause the reduction in effective radius of particle, cloud liquid water content and cloud optical thickness, and the increase of the number concentration of liquid cloud particles as well, (2) The aerosol extinction coefficients were decreased with the increase of height. The value of the aerosol extinction coefficients in desert area was greater than that in the area of Gansu Province due to urbanization. Distribution of the aerosol extinction coefficients in spring was nearly the same as the annual average. (3) Using aerosol products of the vertical characteristics from CALIOP/CALIOPSO, aerosol was classified during dust events, and with NAPPS Global aerosol model, daily distribution of the dust aerosol concentration was given, showing the transport and diffusion of dust aerosol. With HYSPLIT trajectory model dust transportation path of the sand dust source areas was simulated and identified. During the outbreak of dust event dust aerosol was mainly distributed over the surface about 3km, with depolarization ratio at 0.4 and color ratio at 1.2. During the dust events were close to weak and stop, dust aerosol was mainly distributed over the surface under 2 km, with depolarization ratio from 0.2 to 0.3, and color ratio about 1.

  15. Interstellar dust laser explorer: a new instrument for elemental and isotopic analysis and imaging of interstellar and interplanetary dust.

    PubMed

    Henkel, Torsten; Tizard, Julia; Blagburn, David J; Lyon, Ian C

    2007-05-01

    We present the performance characteristics of a time-of-flight secondary ion mass spectrometer designed for 157 nm laser postionization of sputtered neutrals for high sensitivity elemental and isotopic analyses. The instrument was built with the aim of analyzing rare element abundances in micron to submicron samples such as interstellar grains and cometary dust. Relative sensitivity factors have been determined for secondary ion mass spectrometry which show an exponential dependency against the first ionization potential. This allows elemental abundances to be measured with errors below 25% for most major elements. The accuracy for isotope ratios, where isotopes can be resolved from isobaric interferences, is usually limited only by counting statistics. In laser secondary neutral mass spectrometry, the spatial and temporal overlaps between the laser and sputtered neutral atoms are modeled and predictions of total detection efficiency and isotopic and elemental fractionation are compared with experimental data. Relative sensitivity factors for laser-ionized secondary neutrals from a stainless steel standard are found to vary less than 3% above saturation laser pulse energy enabling more accurate quantification.

  16. Stereoscopy of dust density waves under microgravity: Velocity distributions and phase-resolved single-particle analysis

    SciTech Connect

    Himpel, Michael Killer, Carsten; Melzer, André; Bockwoldt, Tim; Piel, Alexander; Ole Menzel, Kristoffer

    2014-03-15

    Experiments on dust-density waves have been performed in dusty plasmas under the microgravity conditions of parabolic flights. Three-dimensional measurements of a dust density wave on a single particle level are presented. The dust particles have been tracked for many oscillation periods. A Hilbert analysis is applied to obtain trajectory parameters such as oscillation amplitude and three-dimensional velocity amplitude. While the transverse motion is found to be thermal, the velocity distribution in wave propagation direction can be explained by harmonic oscillations with added Gaussian (thermal) noise. Additionally, it is shown that the wave properties can be reconstructed by means of a pseudo-stroboscopic approach. Finally, the energy dissipation mechanism from the kinetic oscillation energy to thermal motion is discussed and presented using phase-resolved analysis.

  17. The Dust Environment of the Moon

    NASA Astrophysics Data System (ADS)

    Horanyi, M.; Szalay, J.; Gruen, E.; Glenar, D.; Wang, X.; Zakharov, A.

    2016-05-01

    We will briefly review the history of the observations of the lunar dust environment, but mainly focus on the results of the LADEE mission, and the recent laboratory results on the charging and mobilization of dust particles on regolith surfaces.

  18. Dust agglomeration

    NASA Technical Reports Server (NTRS)

    2000-01-01

    John Marshall, an investigator at Ames Research Center and a principal investigator in the microgravity fluid physics program, is studying the adhesion and cohesion of particles in order to shed light on how granular systems behave. These systems include everything from giant dust clouds that form planets to tiny compressed pellets, such as the ones you swallow as tablets. This knowledge should help us control the grains, dust, and powders that we encounter or use on a daily basis. Marshall investigated electrostatic charge in microgravity on the first and second U.S. Microgravity Laboratory shuttle missions to see how grains aggregate, or stick together. With gravity's effects eliminated on orbit, Marshall found that the grains of sand that behaved ever so freely on Earth now behaved like flour. They would just glom together in clumps and were quite difficult to disperse. That led to an understanding of the prevalence of the electrostatic forces. The granules wanted to aggregate as little chains, like little hairs, and stack end to end. Some of the chains had 20 or 30 grains. This phenomenon indicated that another force, what Marshall believes to be an electrostatic dipole, was at work.(The diagram on the right emphasizes the aggregating particles in the photo on the left, taken during the USML-2 mission in 1995.)

  19. Laboratory Simulation of Impacts upon Aluminum Foils of the Stardust Spacecraft: Calibration of Dust Particle Size from Comet Wild 2

    NASA Technical Reports Server (NTRS)

    Kearsley, A. T.; Burchell, M. J.; Horz, F.; Cole, M. J.; Schwandt, C. S.

    2006-01-01

    Metallic aluminium alloy foils exposed on the forward, comet-facing surface of the aerogel tray on the Stardust spacecraft are likely to have been impacted by the same cometary particle population as the dedicated impact sensors and the aerogel collector. The ability of soft aluminium alloy to record hypervelocity impacts as bowl-shaped craters offers an opportunistic substrate for recognition of impacts by particles of a wide potential size range. In contrast to impact surveys conducted on samples from low Earth orbit, the simple encounter geometry for Stardust and Wild 2, with a known and constant spacecraft-particle relative velocity and effective surface-perpendicular impact trajectories, permits closely comparable simulation in laboratory experiments. For a detailed calibration programme we have selected a suite of spherical glass projectiles of uniform density and hardness characteristics, with well-documented particle size range from 10 microns to nearly 100 microns. Light gas gun buckshot firings of these particles at approximately 6km s)exp -1) onto samples of the same foil as employed on Stardust have yielded large numbers of craters. Scanning electron microscopy of both projectiles and impact features has allowed construction of a calibration plot, showing a linear relationship between impacting particle size and impact crater diameter. The close match between our experimental conditions and the Stardust mission encounter parameters should provide another opportunity to measure particle size distributions and fluxes close to the nucleus of Wild 2, independent of the active impact detector instruments aboard the Stardust spacecraft.

  20. An attempt to understand the properties of interstellar dust based on space exposure experiment of laboratory-synthesized carbonaceous samples using ISS/KIBO/ExHAM

    NASA Astrophysics Data System (ADS)

    Sakon, Itsuki; Onaka, Takashi; Kimura, Yuki; Kimura, Seiji; Nakamura, Masato; Ichimura, Atsushi; Wada, Setsuko

    2016-07-01

    We present the project overview and the latest status of our space exposure experiments of various solid samples with International Space Station (ISS)/KIBO/ExHAM. The major goals of this project are to identify the composition and properties of dust formed in the Asymptotic Giant Banch (AGB) stellar wind and to demonstrate how it is chemically and physically altered in nature in the circumstellar environment until it becomes a member of the interstellar medium. In particular, we aim to investigate the properties of 'astronomical' polycyclic aromatic hydrocarbons (PAHs), the carrier of the unidentified infrared (UIR) bands which have been observed ubiquitously in various astrophysical environments. Various experiment samples including the laboratory synthesized carbonaceous solids such as quenched carbonaceous composites (QCCs), deuterated quenched carbonaceous composites (deut-QCCs) and nitrogen-containing carbonaceous composites (NCCs) are brought to the ISS and are exposed in the space exposure environment for approximately one year by means of the ExHAM. The difference in properties of our experiment samples between before and after the space exposure experiment is investigated based on infrared micro-spectroscopy, X-ray photoelectron spectroscopy (XPS), and electron microscopic observations, etc.

  1. Analysis of volatiles present in interplanetary dust and stratospheric particles collected on large area collectors

    NASA Technical Reports Server (NTRS)

    Hartmetz, C. P.; Gibson, E. K., Jr.; Blanford, G. E.

    1991-01-01

    Results are presented from an analysis of six chondritic interplanetary dust particles (IDPs) and 22 other stratospheric particles collected on large-area collector, carried out in order to obtain information on the nature, distribution, and form of volatiles in IDPs. A laser microprobe/mass spectrometer (LMMS) was used to extract volatile elements and molecules from particles larger than 10 microns, and an improved hexane rinsing technique was developed for the removal of contaminants. Results show that, because of contamination from silicone oil, freon, and hexane, most of the LMMS signal from IDPs can be interpreted as arising from contamination. Therefore, a species was not considered indigenous unless the signal was an order of magnitude greater in abundance than that released from a pure contaminant coated on gold.

  2. The Lunar Dust Environment

    NASA Astrophysics Data System (ADS)

    Szalay, Jamey Robert

    Planetary bodies throughout the solar system are continually bombarded by dust particles, largely originating from cometary activities and asteroidal collisions. Surfaces of bodies with thick atmospheres, such as Venus, Earth, Mars and Titan are mostly protected from incoming dust impacts as these particles ablate in their atmospheres as 'shooting stars'. However, the majority of bodies in the solar system have no appreciable atmosphere and their surfaces are directly exposed to the flux of high speed dust grains. Impacts onto solid surfaces in space generate charged and neutral gas clouds, as well as solid secondary ejecta dust particles. Gravitationally bound ejecta clouds forming dust exospheres were recognized by in situ dust instruments around the icy moons of Jupiter and Saturn, and had not yet been observed near bodies with refractory regolith surfaces before NASA's Lunar Dust and Environment Explorer (LADEE) mission. In this thesis, we first present the measurements taken by the Lunar Dust Explorer (LDEX), aboard LADEE, which discovered a permanently present, asymmetric dust cloud surrounding the Moon. The global characteristics of the lunar dust cloud are discussed as a function of a variety of variables such as altitude, solar longitude, local time, and lunar phase. These results are compared with models for lunar dust cloud generation. Second, we present an analysis of the groupings of impacts measured by LDEX, which represent detections of dense ejecta plumes above the lunar surface. These measurements are put in the context of understanding the response of the lunar surface to meteoroid bombardment and how to use other airless bodies in the solar system as detectors for their local meteoroid environment. Third, we present the first in-situ dust measurements taken over the lunar sunrise terminator. Having found no excess of small grains in this region, we discuss its implications for the putative population of electrostatically lofted dust.

  3. Low frequency modes and instability analysis in non-thermal dusty magnetoplasma considering dust charge fluctuation and polarization force

    NASA Astrophysics Data System (ADS)

    Sharma, Prerana; Jain, Shweta; Patidar, Archana

    2017-01-01

    The effect of non-thermal ion population on self-gravitational instability of magnetized dusty plasma considering electrons are in Maxwell-Boltzmann distribution has been investigated. The dust dynamics is described including polarization force, thermal velocity, and charge fluctuation dust. The modified general dispersion relation has been derived including non-thermal ion population, polarization force, and dust charge fluctuation for self-gravitating dusty plasma system, using the normal mode analysis method. The obtained general dispersion relation is discussed in parallel and perpendicular modes of propagation. The population of non-thermal ion, polarization force and dust charge fluctuation affect the self-gravitational instability criteria in both the modes of propagation while the magnetic field affects the instability criterion only in perpendicular mode of propagation. The domains of instability has been discussed analytically to signify the importance of considered parameters. The stability of the self-gravitating dusty plasma system has been analyzed using Routh-Hurwitz stability criterion. Numerical calculations have been performed to analyze the effects of non-thermal ion population, polarization force, and dust charge fluctuation on the growth rate of self-gravitational instability. The results of the present work can be useful in self-gravitating dusty plasma found in space and the interstellar medium such as the interstellar molecular clouds where non-thermally distributed ions are the species of the plasma matter.

  4. Use of fluorinated polybrominated diphenyl ethers and simplified cleanup for the analysis of polybrominated diphenyl ethers in house dust

    EPA Science Inventory

    A simple, cost-effective method is described for the analysis of polybrominated diphenyl ethers (PBDEs) in house dust using pressurized fluid extraction, cleanup with modified silica solid phase extraction tubes, and fluorinated internal standards. There are 14 PBDE congeners inc...

  5. The proposed Diagnostic Instrumentation and Analysis Laboratory, Mississippi State University

    SciTech Connect

    1994-11-01

    The Department of Energy (DOE) proposes to authorize Mississippi State University (MSU) to proceed with the detailed design, construction and equipping of the proposed Diagnostic Instrumentation and Analysis Laboratory (DIAL). DOE grant funds are available to the University for the limited purpose of performing preliminary studies, including analysis necessary to conduct this environmental assessment. The proposed facility would be located in the Mississippi Research and Technology Park, adjacent to the Mississippi Agriculture and Forestry Experiment Station campus in Starkville, Mississippi. Total project cost is estimated at $7,953,600. This proposed laboratory would be designed to conduct research into combustion devices related to waste management and environmental restoration that is of importance to industry and government. The proposed facility`s role would be to develop diagnostic instrumentation capabilities in the area of combustion and related processes.

  6. Metals and metalloids in atmospheric dust: Use of lead isotopic analysis for source apportionment

    NASA Astrophysics Data System (ADS)

    Felix Villar, Omar I.

    Mining activities generate aerosol in a wide range of sizes. Smelting activities produce mainly fine particles (<1 microm). On the other hand, milling, crushing and refining processes, as well tailings management, are significant sources of coarse particles (> 1 microm). The adverse effects of aerosols on human health depend mainly on two key characteristics: size and chemical composition. One of the main objectives of this research is to analyze the size distribution of contaminants in aerosol produced by mining operations. For this purpose, a Micro-Orifice Uniform Deposit Impactor (MOUDI) was utilized. Results from the MOUDI samples show higher concentrations of the toxic elements like lead and arsenic in the fine fraction (<1 microm). Fine particles are more likely to be deposited in the deeper zones of the respiratory system; therefore, they are more dangerous than coarse particles that can be filtered out in the upper respiratory system. Unfortunately, knowing the total concentration of contaminants does not give us enough information to identify the source of contamination. For this reason, lead isotopes have been introduced as fingerprints for source apportionment. Each source of lead has specific isotopic ratios; by knowing these ratios sources can be identified. During this research, lead isotopic ratios were analyzed at different sites and for different aerosol sizes. From these analyses it can be concluded that lead isotopes are a powerful tool to identify sources of lead. Mitigation strategies could be developed if the source of contamination is well defined. Environmental conditions as wind speed, wind direction, relative humidity and precipitation have an important role in the concentration of atmospheric dust. Dry environments with low relative humidity are ideal for the transport of aerosols. Results obtained from this research show the relationship between dust concentrations and meteorological parameters. Dust concentrations are highly correlated

  7. Talc dust pneumoconiosis.

    PubMed

    Berner, A; Gylseth, B; Levy, F

    1981-01-01

    Various types of mineral dust can induce interstitial pulmonary fibrosis, but there is no definite correlation between lung X-ray findings, tissue lesions and the type of dust. In this paper, we report on the post mortem verification of talcosis by lung tissue analysis, using light microscopy, scanning electron microscopy, energy dispersive x-ray microanalysis and x-ray diffractometry.

  8. [Advanced data analysis and visualization for clinical laboratory].

    PubMed

    Inada, Masanori; Yoneyama, Akiko

    2011-01-01

    This paper describes visualization techniques that help identify hidden structures in clinical laboratory data. The visualization of data is helpful for a rapid and better understanding of the characteristics of data sets. Various charts help the user identify trends in data. Scatter plots help prevent misinterpretations due to invalid data by identifying outliers. The representation of experimental data in figures is always useful for communicating results to others. Currently, flexible methods such as smoothing methods and latent structure analysis are available owing to the presence of advanced hardware and software. Principle component analysis, which is a well-known technique used to reduce multidimensional data sets, can be carried out on a personal computer. These methods could lead to advanced visualization with regard to exploratory data analysis. In this paper, we present 3 examples in order to introduce advanced data analysis. In the first example, a smoothing spline was fitted to a time-series from the control chart which is not in a state of statistical control. The trend line was clearly extracted from the daily measurements of the control samples. In the second example, principal component analysis was used to identify a new diagnostic indicator for Graves' disease. The multi-dimensional data obtained from patients were reduced to lower dimensions, and the principle components thus obtained summarized the variation in the data set. In the final example, a latent structure analysis for a Gaussian mixture model was used to draw complex density functions suitable for actual laboratory data. As a result, 5 clusters were extracted. The mixed density function of these clusters represented the data distribution graphically. The methods used in the above examples make the creation of complicated models for clinical laboratories more simple and flexible.

  9. African Dust Blows over the Caribbean

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Shuttle astronauts frequently track Saharan dust storms as they blow from north Africa across the Atlantic Ocean. Dust palls blowing from Africa take about a week to cross the Atlantic. Recently, researchers have linked Saharan dust to coral disease, allergic reactions in humans, and red tides. The top photograph, a classic image showing African dust over the Caribbean, was taken at a time when few scientists had considered the possibility. The image was taken by Space Shuttle astronauts on July 11, 1994 (STS065-75-47). This photograph looks southwest over the northern edge of a large trans-Atlantic dust plume that blew off the Sahara desert in Africa. In this view, Caicos Island in the Bahamas and the mountainous spines of Haiti are partly obscured by the dust. Closer to the foreground, (about 26 degrees north latitude), the skies are clear. The lower photograph (STS105-723-7) was taken by Space Shuttle astronauts while docked to the International Space Station on August 19, 2001. The spacecraft is over the Atlantic Ocean at roughly 45oN, 60oW. The astronauts were looking obliquely to the south; the boundaries of the dust plumes can be traced visually by the abrupt change from clear to hazy atmosphere-the hazy line marks the northern edge of the dust pall near the Caribbean. Images provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.

  10. [Task analysis of clinical laboratory physician in acute hospital].

    PubMed

    Murakami, Junko

    2013-06-01

    Appropriate communications between clinical divisions and clinical laboratories are required to improve the quality of health care in hospitals. In this paper, the routine work of a clinical laboratory physician is presented. 1. In order to support attentive medical practice, we have established a consultation service system for handling questions from medical staff. The main clients are doctors and clinical laboratory technologists. 2. In order to improve the quality of infectious disease analysis, we have recommended obtaining two or more blood culture sets to achieve good sensitivity. The order rate of multiple blood culture sets increased 90% or more in 2011. 3. In order to provide appropriate blood transfusion, we intervene in inappropriate transfusion plans. 4. In order to support prompt decision making, we send E-mails to physicians regarding critical values. 5. We send reports on the morphology of cells(peripheral blood and bone marrow), IEP, flow cytometry, irregular antibodies, and so on. It has been realized that doctors want to know better solutions immediately rather than the best solution tomorrow morning. We would like to contribute to improving the quality of health care in Saitama Cooperative Hospital as clinical laboratory physicians.

  11. Nanoflow Separation of Amino Acids for the Analysis of Cosmic Dust

    NASA Technical Reports Server (NTRS)

    Martin, M. P.; Glavin, D. P.; Dworkin, Jason P.

    2008-01-01

    The delivery of amino acids to the early Earth by interplanetary dust particles, comets, and carbonaceous meteorites could have been a significant source of the early Earth's prebiotic organic inventory. Amino acids are central to modern terrestrial biochemistry as major components of proteins and enzymes and were probably vital in the origin of life. A variety of amino acids have been detected in the CM carbonaceous meteorite Murchison, many of which are exceptionally rare in the terrestrial biosphere including a-aminoisobutyric acid (AIB) and isovaline. AIB has also been detected in a small percentage of Antarctic micrometeorite grains believed to be related to the CM meteorites We report on progress in optimizing a nanoflow liquid chromatography separation system with dual detection via laser-induced-fluorescence time of flight mass spectrometry (nLC-LIF/ToF-MS) for the analysis of o-phthaldialdehydelN-acetyl-L-cysteine (OPA/NAC) labeled amino acids in cosmic dust grains. The very low flow rates (<3 micro-L/min) of nLC over analytical LC (>0.1 ml/min) combined with <2 micron column bead sizes has the potential to produce efficient analyte ionizations andchromatograms with very sharp peaks; both increase sensitivity. The combination of the selectivity (only primary amines are derivatized), sensitivity (>4 orders of magnitude lower than traditional GC-MS techniques), and specificity (compounds identities are determined by both retention time and exact mass) makes this a compelling technique. However, the development of an analytical method to achieve separation of compounds as structurally similar as amino acid monomers and produce the sharp peaks required for maximum sensitivity is challenging.

  12. A Modification and Analysis of Lagrangian Trajectory Modeling and Granular Dynamics of Lunar Dust Particles

    NASA Technical Reports Server (NTRS)

    Long, Jason M.; Lane, John E.; Metzger, Philip T.

    2008-01-01

    A previously developed mathematical model is amended to more accurately incorporate the effects of lift and drag on single dust particles in order to predict their behavior in the wake of high velocity gas flow. The model utilizes output from a CFD or DSMC simulation of exhaust from a rocket nozzle hot gas jet. An extension of the Saffman equation for lift based on the research of McLaughlin (1991) and Mei (1992) is used, while an equation for the Magnus force modeled after the work of Oesterle (1994) and Tsuji et al (1985) is applied. A relationship for drag utilizing a particle shape factor (phi = 0.8) is taken from the work of Haider and Levenspiel (1989) for application to non-spherical particle dynamics. The drag equation is further adjusted to account for rarefaction and compressibility effects in rarefied and high Mach number flows according to the work of Davies (1945) and Loth (2007) respectively. Simulations using a more accurate model with the correction factor (Epsilon = 0.8 in a 20% particle concentration gas flow) given by Richardson and Zaki (1954) and Rowe (1961) show that particles have lower ejection angles than those that were previously calculated. This is more prevalent in smaller particles, which are shown through velocity and trajectory comparison to be more influenced by the flow of the surrounding gas. It is shown that particles are more affected by minor changes to drag forces than larger adjustments to lift forces, demanding a closer analysis of the shape and behavior of lunar dust particles and the composition of the surrounding gas flow.

  13. [Distribution Characteristics and Source Analysis of Polycyclic Aromatic Hydrocarbons (PAHs) in Surface Dust of Xi'an City, China].

    PubMed

    Wang, Li; Wang, Li-jun; Shi, Xing-min; Lu, Xin-wei

    2016-04-15

    A total of 58 surface dust samples were collected from Xi'an city. The concentrations of 16 priority polycyclic aromatic hydrocarbons (PAHs) were analyzed by gas chromatography with a flame ionization detector (GC-FID). At the same time, the distribution and sources of PAHs in surface dust were studied. The results showed that the concentrations of individual PAH ranged from 14.69 to 6370. 48 microg x kg(-1), and the total concentrations of 16 PAHs (∑16 PAHs) ranged from 5039.67 to 47,738.50 microg x kg(-1), with a mean of 13,845.82 microg x kg(-1). Compared to the Y PAHs levels of other cities, the ∑16 PAHs in surface dust of Xi'an belonged to a relatively higher level. PAHs in surface dust were mainly dominated by high molecular weight PAHs with 4-6 rings and the concentration of 7 carcinogenic PAHs (1 CPAHs) accounted for 46.08% of 3 16PAHs. The mean of ∑16 PAHs in surface dust had the highest concentration at industrial area; followed by the educational area, traffic area, business and traffic area; residential area and parks showed relatively lower concentration. The average content of ∑16 PAHs in surface dust presented an increasing trend along the main urban area--the second ring road--the third ring road. ∑16 PAHs in surface dust had higher concentrations at the industrial areas of the east and west suburbs of Xi'an, the south suburb and the north section of the second ring road; ∑16 PAHs concentrations in the main urban area, north suburb and southeast part of Xi'an were relatively lower. The results of ratio, cluster analysis and principal component analysis showed that PAHs in surface dust were mainly originated from the combustion of fossil fuels and coal combustion. Among them, diesel combustion reached 36.07%, gasoline combustion accounted for 32.31%, and coal combustion was resposbe for 23.40%

  14. Galaxy formation by dust

    NASA Technical Reports Server (NTRS)

    Wang, Boqi; Field, Goerge B.

    1989-01-01

    It has been known since the early 1940's that radiation can cause an instability in the interstellar medium. Absorbing dust particles in an isotropic radiation field shadow each other by a solid angle which is inversely proportional to the square of the distance between the two particles, leading to an inverse-square attractive force - mock gravity. The effect is largest in an optically thin medium. Recently Hogan and White (HW, hereafter) proposed that if the pre-galactic universe contained suitable sources of radiation and dust, instability in the dust distribution caused by mock gravity may have led to the formation of galaxies and galaxy clusters. In their picture of a well-coupled dust-gas medium, HW show that mock gravity begins to dominate gravitational instability when the perturbation becomes optically thin, provided that the radiation field at the time is strong enough. The recent rocket observation of the microwave background at submillimeter wavelengths by Matsumoto et al. might be from pre-galactic stars, the consequence of the absorption of ultraviolet radiation by dust, and infrared reemission which is subsequently redshifted. HW's analysis omits radiative drag, incomplete collisional coupling of gas and dust, finite dust albedo, and finite matter pressure. These effects could be important. In a preliminary calculation including them, the authors have confirmed that mock gravitational instability is effective if there is a strong ultraviolet radiation at the time, but any galaxies that form would be substantially enriched in heavy elements because the contraction of the dust is more rapid than that of the gas. Moreover, since the dust moves with supersonic velocity through the gas soon after the perturbation becomes optically thin, the sputtering of dust particles by gas is significant, so the dust could disappear before the instability develops significantly. They conclude that the mock gravity by dust is not important in galaxy formations.

  15. The speciation of iron in desert dust collected in Gran Canaria (Canary Islands): Combined chemical, magnetic and optical analysis

    NASA Astrophysics Data System (ADS)

    Lázaro, Francisco J.; Gutiérrez, Lucía; Barrón, Vidal; Gelado, María D.

    Atmospheric dust collected on filters at a coastal site in Gran Canaria has been analysed by a combination of chemical, magnetic and optical methods with the aim of determining the iron speciation. The fraction of total iron as particulate (oxyhydr)oxides, determined by the citrate-bicarbonate-dithionite method, was 0.39 ± 0.11 (mean ± s.d.); the fraction of (oxyhydr)oxide iron in ferrimagnetic form, through analysis of the saturation magnetisation, was 0.053 ± 0.038 (mean ± s.d.); and the fraction of haematite iron with respect to the iron in haematite + goethite form, by diffuse reflectance spectroscopy measurements, was 0.47 ± 0.12 (mean ± s.d.). Consistent with these findings, low temperature in-phase and out-of-phase AC susceptibility measurements reveal also the presence of paramagnetic iron, most likely in silicates with ionic substitution, and indicate that, while magnetite or haematite particles may be present in the dust, their particle size should be very small, as the typical magnetic transitions characteristic of large crystals of these oxides are practically impossible to detect. The comparison of the Fe/Al elemental ratios with typical crustal values indicates that the great majority of captured dust iron has a non-anthropogenic origin. Although no significant correlations have been found between the analysed dust properties and the dust provenance, the obtained magnetic data corresponding to the dust collected at this site may be useful, as a middle step, in future magnetic monitoring studies of the iron biogeochemical cycle.

  16. Chronic Obstructive Pulmonary Disease (COPD) and Vapors, Gases, Dusts, or Fumes (VGDF): A Meta-analysis.

    PubMed

    Ryu, Ji Young; Sunwoo, Yu Eun; Lee, Sang-Yoon; Lee, Chae-Kwan; Kim, Jeong-Ho; Lee, Jong-Tae; Kim, Dae-Hwan

    2015-08-01

    To evaluate the association between the risk of chronic obstructive pulmonary disease (COPD) and exposure to vapors, gases, dusts, or fumes (VGDF), we conducted a meta-analysis of epidemiological studies. We searched for studies investigating the relationship between COPD and occupational exposure to VGDF in the adult population. The bibliographic search was conducted in databases (PubMed and Google Scholar). Eleven studies that met predetermined inclusion criteria were included in the meta-analysis. We calculated the pooled odds ratio (OR) with its 95% confidence interval (CI) of COPD for exposure to VGDF using a random-effects model. The presence of publication bias was explored. There was moderate heterogeneity among the included studies (I(2) = 54.3%). In a random-effects model meta-analysis, the pooled OR for exposure to VGDF was 1.43 for COPD (95% CI: 1.19-1.73) compared with no exposure to VGDF. Publication bias was not observed in this study. Our study suggests that exposure to VGDF is associated with a higher risk of COPD. Further prospective cohort studies are needed to confirm this association.

  17. A General Chemistry Laboratory Theme: Spectroscopic Analysis of Aspirin

    NASA Astrophysics Data System (ADS)

    Byrd, Houston; O'Donnell, Stephen E.

    2003-02-01

    In this paper, we describe the introduction of spectroscopy into the general chemistry laboratory using a series of experiments based on a common substance, aspirin. In the first lab the students synthesize and recrystallize aspirin and take melting points of their product, an aspirin standard, and salicylic acid. The students perform the remaining experiments on a rotating basis where the following four labs run simultaneously: structural characterization of the synthesized aspirin by IR and NMR; analysis of synthesized aspirin and commercial products by UV vis spectroscopy; analysis of synthesized aspirin and commercial products by HPLC; and analysis of calcium in commercial buffered aspirin tablets by AAS. In each of the analysis experiments, students collect, graph, and analyze their data using a spreadsheet. We have found that this series of labs has been very beneficial to our students. From the course evaluations, students indicate that they are beginning to understand how chemistry is applied outside of the classroom.

  18. Validation of Real-time Dust Forecasting for the Iraq Region of Southwest Asia

    NASA Astrophysics Data System (ADS)

    Liu, M.; Westphal, D. L.; Walker, A. L.; Holt, T. R.; Richardson, K. A.; Miller, S. D.

    2005-12-01

    Dust storms are a significant weather phenomenon in the Iraq region in spring. Real-time dust forecasting using the Navy's Coupled Ocean/Atmospheric Mesoscale Prediction System (COAMPS? with an inline dust aerosol model was conducted for the Operation Iraqi Freedom (OIF) in March and April 2003. Daily forecasts of dust mass concentration, visibility and optical depth were produced out to 72 hours on nested grids of 9-, 27- and 81-km resolution. In this work, the model performance is evaluated using ground weather reports, visibility observations, and enhanced satellite retrievals. COAMPS successfully predicted the timing, magnitude, duration and spatial coverage of the five major dust episodes. A detailed validation of the severest dust storm of OIF shows the high-resolution forecasts of the dust front are consistent with satellite images and the corresponding cold front observations. A statistical analysis of dust visibility for the OIF period reveals that COAMPS generates higher bias, RMS and relative errors at the stations having high frequency of dust storms, and that the errors are resolution dependent with the 9-km grid errors being the lowest. The calculation of forecast rates shows COAMPS achieved a dust storm prediction rate of 50 to 90% and threat score of 0.3 to 0.55 at the stations with frequent dust storms. Overall it predicted more than 85% of the observed dust and non-dust weather at all stations. A comparison of the forecast rates and statistical errors for the forecasts of different lengths (12 to 72 hours) for both dust and dynamics fields reveals little dependence of model accuracy on forecast length, implying that COAMPS accurately and consistently forecasted the severest of the OIF dust events. (COAMPS?is a registered trademark of the Naval Research Laboratory).

  19. Canadian inter-laboratory organically bound tritium (OBT) analysis exercise.

    PubMed

    Kim, S B; Olfert, J; Baglan, N; St-Amant, N; Carter, B; Clark, I; Bucur, C

    2015-12-01

    Tritium emissions are one of the main concerns with regard to CANDU reactors and Canadian nuclear facilities. After the Fukushima accident, the Canadian Nuclear Regulatory Commission suggested that models used in risk assessment of Canadian nuclear facilities be firmly based on measured data. Procedures for measurement of tritium as HTO (tritiated water) are well established, but there are no standard methods and certified reference materials for measurement of organically bound tritium (OBT) in environmental samples. This paper describes and discusses an inter-laboratory comparison study in which OBT in three different dried environmental samples (fish, Swiss chard and potato) was measured to evaluate OBT analysis methods currently used by CANDU Owners Group (COG) members. The variations in the measured OBT activity concentrations between all laboratories were less than approximately 20%, with a total uncertainty between 11 and 17%. Based on the results using the dried samples, the current OBT analysis methods for combustion, distillation and counting are generally acceptable. However, a complete consensus OBT analysis methodology with respect to freeze-drying, rinsing, combustion, distillation and counting is required. Also, an exercise using low-level tritium samples (less than 100 Bq/L or 20 Bq/kg-fresh) would be useful in the near future to more fully evaluate the current OBT analysis methods.

  20. The Martian dust cycle: A proposed model

    NASA Technical Reports Server (NTRS)

    Greeley, Ronald

    1987-01-01

    Despite more than a decade of study of martian dust storms, many of their characteristics and associated processes remain enigmatic, including the mechanisms for dust raising, modes of settling, and the nature of dust deposits. However, observations of Mars dust, considerations of terrestrial analogs, theoretical models, and laboratory simulations permit the formulation of a Martian Dust Cycle Model, which consists of three main processes: (1) suspension threshold, (2) transportation, and (3) deposition; two associated processes are also included: (4) dust removal and (5) the addition of new dust to the cycle. Although definitions vary, dust includes particles less than 4 to approx. 60 microns in diameter, which by terrestrial usage includes silt, loess, clay, and aerosolic dust particles. The dust cycle model is explained.

  1. Analysis of Measurements of Saharan Dust by Airborne and Ground-based Remote Sensing Methods during the Puerto Rico Dust Experiment (PRIDE)

    NASA Technical Reports Server (NTRS)

    Reid, Jeffrey S.; Kinney, James E.; Westphal, Douglas L.; Holben, Brent N.; Welton, E. Judd; Tsay, Si-Chee; Eleuterio, Daniel P.; Campbell, James; Christopher, Sundar A.; Jonsson, Haflidi H.

    2003-01-01

    For 26 days in mid-June and July 2000, a research group comprised of U.S. Navy, NASA, and university scientists conducted the Puerto Rico Dust Experiment (PRIDE). In this paper we give a brief overview of mean meteorological conditions during the study. We focus on findings on African dust transported into the Caribbean utilizing Navajo aircraft and AERONET Sun photometer data. During the study midvisible aerosol optical thickness (AOT) in Puerto Rico averaged 0.25, with a maximum less than 0.5 and with clean marine periods of _0.08. Dust AOTs near the coast of Africa (Cape Verde Islands and Dakar) averaged _0.4, 30% less than previous years. By analyzing dust vertical profiles in addition to supplemental meteorology and MPLNET lidar data we found that dust transport cannot be easily categorized into any particular conceptual model. Toward the end of the study period, the vertical distribution of dust was similar to the commonly assumed Saharan Air Layer (SAL) transport. During the early periods of the study, dust had the highest concentrations in the marine and convective boundary layers with only a, weak dust layer in the SAL being present, a state usually associated with wintertime transport patterns. We corroborate the findings of Maring et al. that in most cases, there was an unexpected lack of vertical stratification of dust particle size. We systematically analyze processes which may impact dust vertical distribution and determine and speculate that dust vertical distribution predominately influenced by flow patterns over Africa and differential advection couple with mixing by easterly waves and regional subsidence.

  2. Repellent activity of desiccant dusts and conidia of the entomopathogenic fungus Beauveria bassiana when tested against poultry red mites (Dermanyssus gallinae) in laboratory experiments.

    PubMed

    Kilpinen, Ole; Steenberg, Tove

    2016-11-01

    Desiccant dusts and entomopathogenic fungi have previously been found to hold potential against the poultry red mite, which is an important pest in egg production and notoriously difficult to control. Both control agents may cause repellence in other arthropods and potentially also influence control levels adversely when used against the poultry red mite. Five desiccant dust products with good efficacy against the poultry red mite Dermanyssus gallinae caused avoidance behavior in mites when tested in bioassays. The repellent activity was correlated with efficacy, which was found to depend on both dose and relative humidity (RH). However, one desiccant dust was significantly less repellent compared to other dusts with similar levels of efficacy. Further, dry conidia of the fungus Beauveria bassiana were also shown to be repellent to poultry red mites, both when applied on its own and when admixed with a low dose of the desiccant dust Diamol. The pick-up of desiccant dust particles and fungus conidia from treated surfaces by mites did not differ depending on RH, whereas the overall efficacy of the two control agents were significantly higher at 75 than at 85 % RH. In addition, the combined effect of the two substances was synergistic when tested in a bioassay where mites could choose whether to cross a treated surface. This is the first time a member of Acari has been shown to be repelled by desiccant dusts and by conidia of an entomopathogenic fungus.

  3. The Laser Dust Detector - a strategy for in-situ dust detection in planetary ice sheets

    NASA Astrophysics Data System (ADS)

    Mogensen, C.; Hecht, M. H.; Carsey, F.; Lane, A. L.

    2004-12-01

    and bubbles to be opaque, or somewhere in between. A Cryobot instrumented with a Laser Dust Detector and an additional light source would be able to profile the ice column either by penetrating a rather clear ice sheet or by imaging the wall of the melt hole of an opaque ice sheet. Results from analysis of dust embedded in archived ice cores as well as `artificial ice' made in the laboratory will be shown. Applications for planetary in-situ dust detection will be discussed.

  4. Individual Particle TOF-SIMS Imaging Analysis of Aerosol Collected During the April 2001 Asian Dust Event.

    NASA Astrophysics Data System (ADS)

    Peterson, R. E.

    2002-12-01

    Time of Flight Secondary Ion Mass Spectroscopy can provide information regarding the surface chemistry, including both organic and inorganic compounds, of individual atmospheric aerosol in themicrometer size range. X-ray analysis has commonly been used to analyze the composition of single particles but has several important limitations. Principally, X-ray analysis cannot be used to study organic compounds in the aerosol, it offers low sensitivity for light elements common in crustal material and it cannot distinguish isotopes. TOF-SIMS has the potential to provide superior performance in these areas. We have developed statistical image processing methods to allow extraction of individual particle mass spectra from TOF-SIMS images. In mid April 2001 a strong Asian dust event was tracked by the NASA TOMS satellite across the Pacific Ocean and into the continental United States. While Asian dust deposition is common in Hawaii, strong events characterized by significant visibility degradation have been much less frequently reported in the Rocky Mountain west. Samples were taken during and after the event at the University of Utah in Salt Lake City, Utah (SLC). Size segregated samples were collected on Al substrates using an 8 stage cascade impactor and total aerosol samples were collected with 47 mm Fluoropore filters. Surface and depth profile analysis of the particles was performed using a Phi Trift I TOF-SIMS instrument. Statistical methods, including PCA, mixture models and neural networks, were used to extract spectra of individual particles from the TOF-SIMS images and to classify particles based on their surface chemistry and depth profiles. Differences in both the chemistry and size distribution of the particles could be seen between the aerosol collected during the Asian dust event and aerosol collected post-event at the University of Utah site. Positive TOF-SIMS spectra of SLC urban aerosol were dominated by sub-micrometer organics, and negative spectra

  5. Laboratory intercomparison of the dicentric chromosome analysis assay.

    PubMed

    Beinke, C; Barnard, S; Boulay-Greene, H; De Amicis, A; De Sanctis, S; Herodin, F; Jones, A; Kulka, U; Lista, F; Lloyd, D; Martigne, P; Moquet, J; Oestreicher, U; Romm, H; Rothkamm, K; Valente, M; Meineke, V; Braselmann, H; Abend, M

    2013-08-01

    The study design and obtained results represent an intercomparison of various laboratories performing dose assessment using the dicentric chromosome analysis (DCA) as a diagnostic triage tool for individual radiation dose assessment. Homogenously X-irradiated (240 kVp, 1 Gy/min) blood samples for establishing calibration data (0.25-5 Gy) as well as blind samples (0.1-6.4 Gy) were sent to the participants. DCA was performed according to established protocols. The time taken to report dose estimates was documented for each laboratory. Additional information concerning laboratory organization/characteristics as well as assay performance was collected. The mean absolute difference (MAD) was calculated and radiation doses were merged into four triage categories reflecting clinical aspects to calculate accuracy, sensitivity and specificity. The earliest report time was 2.4 days after sample arrival. DCA dose estimates were reported with high and comparable accuracy, with MAD values ranging between 0.16-0.5 Gy for both manual and automated scoring. No significant differences were found for dose estimates based either on 20, 30, 40 or 50 cells, suggesting that the scored number of cells can be reduced from 50 to 20 without loss of precision of triage dose estimates, at least for homogenous exposure scenarios. Triage categories of clinical significance could be discriminated efficiently using both scoring procedures.

  6. Evaluation of the cytotoxicity of organic dust components on THP1 monocytes-derived macrophages using high content analysis.

    PubMed

    Ramery, Eve; O'Brien, Peter J

    2014-03-01

    Organic dust contains pathogen-associated molecular patterns (PAMPs) which can induce significant airway diseases following chronic exposure. Mononuclear phagocytes are key protecting cells of the respiratory tract. Several studies have investigated the effects of PAMPs and mainly endotoxins, on cytokine production. However the sublethal cytotoxicity of organic dust components on macrophages has not been tested yet. The novel technology of high content analysis (HCA) is already used to assess subclinical drug-induced toxicity. It combines the capabilities of flow cytometry, intracellular fluorescence probes, and image analysis and enables rapid multiple analyses in large numbers of samples. In this study, HCA was used to investigate the cytotoxicity of the three major PAMPs contained in organic dust, i.e., endotoxin (LPS), peptidoglycan (PGN) and β-glucans (zymosan) on THP-1 monocyte-derived macrophages. LPS was used at concentrations of 0.005, 0.01, 0.02, 0.05, 0.1, and 1 μg/mL; PGN and zymosan were used at concentrations of 1, 5, 10, 50, 100, and 500 μg/mL. Cells were exposed to PAMPs for 24 h. In addition, the oxidative burst and the phagocytic capabilities of the cells were tested. An overlap between PGN intrinsic fluorescence and red/far-red fluorescent dyes occurred, rendering the evaluation of some parameters impossible for PGN. LPS induced sublethal cytotoxicity at the lowest dose (from 50 ng/mL). However, the greatest cytotoxic changes occurred with zymosan. In addition, zymosan, but not LPS, induced phagosome maturation and oxidative burst. Given the fact that β-glucans can be up to 100-fold more concentrated in organic dust than LPS, these results suggest that β-glucans could play a major role in macrophage impairment following heavy dust exposure and will merit further investigation in the near future.

  7. Cesium Speciation in Dust from Municipal Solid Waste and Sewage Sludge Incineration by Synchrotron Radiation Micro-X-ray Analysis.

    PubMed

    Shiota, Kenji; Takaoka, Masaki; Fujimori, Takashi; Oshita, Kazuyuki; Terada, Yasuko

    2015-11-17

    The chemical behavior of Cs in waste incineration processes is important to consider when disposing of radionuclide-contaminated waste from the Fukushima Daiichi nuclear power plant accident in Japan. To determine the speciation of Cs, we attempted the direct speciation of trace amounts of stable Cs in the dust from municipal solid waste incineration (MSWI) and sewage sludge incineration (SSI) by micro-X-ray fluorescence (μ-XRF) and micro-X-ray absorption fine structure (μ-XAFS) at the SPring-8 facility. The μ-XRF results revealed that locally produced Cs was present in MSWI and SSI dust within the cluster size range of 2-10 μm. The μ-XAFS analysis confirmed that the speciation of Cs in MSWI dust was similar to that of CsCl, while in SSI dusts it was similar to pollucite. The solubility of Cs was considered to be influenced by the exact Cs species present in incineration residue.

  8. Circumstellar dust

    NASA Technical Reports Server (NTRS)

    Dwek, E.

    1986-01-01

    The presence of dust in the general interstellar medium is inferred from the extinction, polarization, and scattering of starlight; the presence of dark nebulae; interstellar depletions; the observed infrared emission around certain stars and various types of interstellar clouds. Interstellar grains are subject to various destruction mechanisms that reduce their size or even completely destroy them. A continuous source of newly formed dust must therefore be present for dust to exist in the various phases of the interstellar medium (ISM). The working group has the following goals: (1) review the evidences for the formation of dust in the various sources; (2) examine the clues to the nature and composition of the dust; (3) review the status of grain formation theories; (4) examine any evidence for the processing of the dust prior to its injection into the interstellar medium; and (5) estimate the relative contribution of the various sources to the interstellar dust population.

  9. Synchrotron FTIR Examination of Interplanetary Dust Particles: An Effort to Determine the Compounds and Minerals in Interstellar and Circumstellar Dust

    NASA Technical Reports Server (NTRS)

    Flynn, G. J.; Keller, L. P.

    2002-01-01

    Some interplanetary dust particles (IDPs), collected by NASA from the Earth's stratosphere, are the most primitive extraterrestrial material available for laboratory analysis. Many exhibit isotopic anomalies in H, N, and O, suggesting they contain preserved interstellar matter. We report the preliminary results of a comparison of the infrared absorption spectra of subunits of the IDPs with astronomical spectra of interstellar grains.

  10. Applied behavior analysis: New directions from the laboratory

    PubMed Central

    Epling, W. Frank; Pierce, W. David

    1983-01-01

    Applied behavior analysis began when laboratory based principles were extended to humans inorder to change socially significant behavior. Recent laboratory findings may have applied relevance; however, the majority of basic researchers have not clearly communicated the practical implications of their work. The present paper samples some of the new findings and attempts to demonstrate their applied importance. Schedule-induced behavior which occurs as a by-product of contingencies of reinforcement is discussed. Possible difficulties in treatment and management of induced behaviors are considered. Next, the correlation-based law of effect and the implications of relative reinforcement are explored in terms of applied examples. Relative rate of reinforcement is then extended to the literature dealing with concurrent operants. Concurrent operant models may describe human behavior of applied importance, and several techniques for modification of problem behavior are suggested. As a final concern, the paper discusses several new paradigms. While the practical importance of these models is not clear at the moment, it may be that new practical advantages will soon arise. Thus, it is argued that basic research continues to be of theoretical and practical importance to applied behavior analysis. PMID:22478574

  11. Residual Strength Analysis Methodology: Laboratory Coupons to Structural Components

    NASA Technical Reports Server (NTRS)

    Dawicke, D. S.; Newman, J. C., Jr.; Starnes, J. H., Jr.; Rose, C. A.; Young, R. D.; Seshadri, B. R.

    2000-01-01

    The NASA Aircraft Structural Integrity (NASIP) and Airframe Airworthiness Assurance/Aging Aircraft (AAA/AA) Programs have developed a residual strength prediction methodology for aircraft fuselage structures. This methodology has been experimentally verified for structures ranging from laboratory coupons up to full-scale structural components. The methodology uses the critical crack tip opening angle (CTOA) fracture criterion to characterize the fracture behavior and a material and a geometric nonlinear finite element shell analysis code to perform the structural analyses. The present paper presents the results of a study to evaluate the fracture behavior of 2024-T3 aluminum alloys with thickness of 0.04 inches to 0.09 inches. The critical CTOA and the corresponding plane strain core height necessary to simulate through-the-thickness effects at the crack tip in an otherwise plane stress analysis, were determined from small laboratory specimens. Using these parameters, the CTOA fracture criterion was used to predict the behavior of middle crack tension specimens that were up to 40 inches wide, flat panels with riveted stiffeners and multiple-site damage cracks, 18-inch diameter pressurized cylinders, and full scale curved stiffened panels subjected to internal pressure and mechanical loads.

  12. Consumer Product Chemicals in Indoor Dust: A Quantitative Meta-analysis of U.S. Studies.

    PubMed

    Mitro, Susanna D; Dodson, Robin E; Singla, Veena; Adamkiewicz, Gary; Elmi, Angelo F; Tilly, Monica K; Zota, Ami R

    2016-10-04

    Indoor dust is a reservoir for commercial consumer product chemicals, including many compounds with known or suspected health effects. However, most dust exposure studies measure few chemicals in small samples. We systematically searched the U.S. indoor dust literature on phthalates, replacement flame retardants (RFRs), perfluoroalkyl substances (PFASs), synthetic fragrances, and environmental phenols and estimated pooled geometric means (GMs) and 95% confidence intervals for 45 chemicals measured in ≥3 data sets. In order to rank and contextualize these results, we used the pooled GMs to calculate residential intake from dust ingestion, inhalation, and dermal uptake from air, and then identified hazard traits from the Safer Consumer Products Candidate Chemical List. Our results indicate that U.S. indoor dust consistently contains chemicals from multiple classes. Phthalates occurred in the highest concentrations, followed by phenols, RFRs, fragrance, and PFASs. Several phthalates and RFRs had the highest residential intakes. We also found that many chemicals in dust share hazard traits such as reproductive and endocrine toxicity. We offer recommendations to maximize comparability of studies and advance indoor exposure science. This information is critical in shaping future exposure and health studies, especially related to cumulative exposures, and in providing evidence for intervention development and public policy.

  13. Consumer Product Chemicals in Indoor Dust: A Quantitative Meta-analysis of U.S. Studies

    PubMed Central

    2016-01-01

    Indoor dust is a reservoir for commercial consumer product chemicals, including many compounds with known or suspected health effects. However, most dust exposure studies measure few chemicals in small samples. We systematically searched the U.S. indoor dust literature on phthalates, replacement flame retardants (RFRs), perfluoroalkyl substances (PFASs), synthetic fragrances, and environmental phenols and estimated pooled geometric means (GMs) and 95% confidence intervals for 45 chemicals measured in ≥3 data sets. In order to rank and contextualize these results, we used the pooled GMs to calculate residential intake from dust ingestion, inhalation, and dermal uptake from air, and then identified hazard traits from the Safer Consumer Products Candidate Chemical List. Our results indicate that U.S. indoor dust consistently contains chemicals from multiple classes. Phthalates occurred in the highest concentrations, followed by phenols, RFRs, fragrance, and PFASs. Several phthalates and RFRs had the highest residential intakes. We also found that many chemicals in dust share hazard traits such as reproductive and endocrine toxicity. We offer recommendations to maximize comparability of studies and advance indoor exposure science. This information is critical in shaping future exposure and health studies, especially related to cumulative exposures, and in providing evidence for intervention development and public policy. PMID:27623734

  14. Titan's Chemical Complexity and Dust

    NASA Astrophysics Data System (ADS)

    Vuitton, Véronique

    Titan, Saturn's largest satellite, harbors one of the richest atmospheric chemistry in the solar system, initiated by the dissociation of the major neutral species (nitrogen and methane) by ultraviolet solar radiation and associated photoelectrons. Until recently, it was believed that the dust observed in the stratosphere (i.e. micrometer size organic aerosols) was formed in situ through an intense neutral chemistry involving complex organic molecules. However, this understanding of Titan’s atmospheric chemistry is being strongly challenged by recent measurements from the Cassini spacecraft. They revealed an extraordinarily complex thermospheric composition with positive ions extending up to at least hundreds of u/q and negative ions up to at least thousands of u/q. These observations indicate that molecular growth starts at much higher altitudes than previously anticipated and suggest that new formation processes have to be put forward. We review our recent work on Titan's upper atmospheric chemistry. We base our discussion on Cassini observations as well as on a new generation of photochemical/microphysical models and laboratory experiments. We argue that positive ion chemistry is at the origin of complex organic molecules, such as benzene, ammonia and hydrogen isocyanide, and that radiative neutral-neutral association can efficiently form alkanes. We find that macromolecules (m/z > 100) attach electrons and therefore attract the abundant positive ions, which ultimately leads to the formation of the dust. In order to infer the dust chemical composition and structure, we turn towards the analysis of laboratory analogues by ultra-high resolution mass spectrometry. Finally, we emphasize that another space mission to Titan with a new generation of instruments is required to validate the effort currently under progress in the laboratory.

  15. 9 CFR 381.207 - Small importations for consignee's personal use, display, or laboratory analysis.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... personal use, display, or laboratory analysis. 381.207 Section 381.207 Animals and Animal Products FOOD..., display, or laboratory analysis. Any poultry product (other than one which is forbidden entry by other... for the personal use of the consignee, or for display or laboratory analysis by the consignee, and...

  16. 9 CFR 590.960 - Small importations for consignee's personal use, display, or laboratory analysis.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... personal use, display, or laboratory analysis. 590.960 Section 590.960 Animals and Animal Products FOOD... personal use, display, or laboratory analysis. Any egg products which are offered for importation, exclusively for the consignee's personal use, display, or laboratory analysis, and not for sale...

  17. 9 CFR 590.960 - Small importations for consignee's personal use, display, or laboratory analysis.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... personal use, display, or laboratory analysis. 590.960 Section 590.960 Animals and Animal Products FOOD... personal use, display, or laboratory analysis. Any egg products which are offered for importation, exclusively for the consignee's personal use, display, or laboratory analysis, and not for sale...

  18. 9 CFR 381.207 - Small importations for consignee's personal use, display, or laboratory analysis.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... personal use, display, or laboratory analysis. 381.207 Section 381.207 Animals and Animal Products FOOD..., display, or laboratory analysis. Any poultry product (other than one which is forbidden entry by other... for the personal use of the consignee, or for display or laboratory analysis by the consignee, and...

  19. [The material character of sand dust and analysis on the cause of formation of the sand-dust storm in northeast district in spring of 2002].

    PubMed

    Jie, Dong-mei; Hu, Ke; Huo, Xin-jiang; Li, Jin; Lü, Jin-fu

    2004-03-01

    The paper analyzed the particle distribution, pollen combination of sand dust storm in northeast district in spring, 2002. It was found that there is abundant pollen, based on pollen combination sand source at new angle can be analyzed, and the distribution laws of the bowling sand and sand dust storm in season, in yearly, in geological periods and mankind historic periods can be explained. The blowing sand and sand dust storm often appeared in geological period and mankind historic period in northeast district, and mainly appeared in winter and in spring and they dropped fluctuationally in fifty years. The frequency of the sand dust storm increased since 2000. The frequency of blowing sand and sand dust storm was controlled by the strength of the monsoon wind in winter. Which the Enino and anti-Enino alternately occurs was influenced by the periodic change of the strength of monsoon wind in winter in Eastern Asia. The cold and dry climate combination in winter and spring was favorable of the occurrence of sand dust weather. The frequency of the sand dust weather will not obviously increase in several years.

  20. Classification of aerosol radiative properties during African desert dust intrusions over southeastern Spain by sector origins and cluster analysis

    NASA Astrophysics Data System (ADS)

    Valenzuela, A.; Olmo, F. J.; Lyamani, H.; Antón, M.; Quirantes, A.; Alados-Arboledas, L.

    2012-03-01

    The main goal of this study is to analyze the dependence of columnar aerosol optical and microphysical properties on source region and transport pathways during desert dust intrusions over Granada (Spain) from January 2005 to December 2010. Columnar aerosol properties have been derived from a non-spherical inversion code using the solar extinction measurements and sky radiances in the principal plane. Two classification methods of the African air masses ending at the study location were used by means of the HYSPLIT back-trajectories analysis. The first one, based on desert dust origin sources, discriminated the optical properties only for sector B (corresponding to western Sahara, northwest Mauritania and southwest Algeria). The particles present marked absorbing properties (low value of single scattering albedo at all wavelengths) during the desert dust events when the air masses were transported from sector A (north Morocco, northwest Algeria). This result may be related to the mixing of desert dust with anthropogenic pollutants from North African industrial areas in addition to the mixing with local anthropogenic aerosol and pollutants transported from European and Mediterranean areas. The second classification method was based on a statistics technique called cluster classification which allows grouping the air masses back trajectories with similar speed and direction of the trajectory. This method showed slight differences in the optical properties between the several transport pathways of air masses. High values of the aerosol optical depth and low mean values of the Angström parameter were associated with longer transport pathways over desert dust sources and slowly moving air masses. Both classification methods showed that the fine mode was mixed with coarse mode, being the fine mode fraction smaller than 55%.

  1. PIA, PUMA, CoMA, CIDA, COSIMA: steps on the way to the in-situ analysis of cometary dust

    NASA Astrophysics Data System (ADS)

    Kissel, Jochen

    2008-09-01

    In the early 1980ies a mission to intercept Halley's comet was announced. The Heidelberg dust group had started to develop a mass spectrometer for ions formed after the impact of a dust particle on a solid target. The design as a reflectron allowed a mass resolution of unity for atomic ions in the range 1 - 140 Da. Flown on 3 missions, as PIA on GIOTTO and as PUMA on VeGa 1+2, it was the first ever to return mass spectra of cometary dust particles. Due to the high impact speeds of 68 and 80 km/s, respectively, mostly atomic ions were registered and consequently neither detailed mineral composition nor the organic chemistry could be identified. It was, however, possible to show the intimate mixture of the organic and mineral components of each of the dust particles only a few microns in size. We found hints for a `light carbon' component, could identify chemical classes in the inorganic component, and signals pointing to the existence of very small <100 nm sized dust in Halley's atmosphere. After this initial opportunity a new mission, CRAF, came up, attempting a rendezvous with a comet nucleus. For this mission, the instrument CoMA, a time-of-flight secondaryion- mass-spectrometer was developed, for which we achieved a mass resolution of m/Δm ≈ 8000 @ m=120, using a pulsed 115In liquid metal ion source. Unfortunately the project was cancelled, before results could be obtained. Shortly after, an enlarged version of the PIA instrument was introduced into the STARDUST S/C to comet Wild-2. For the first time we measured also negative ions from dust impacts, and could identify quinone derivatives, a biologically important chemical compound class, in interstellar dust grains. The spectra of cometary grains were too complex for a detailed analysis due to the relatively low impact speed of 6.2 km/s. A twin instrument was flown on the CONTOUR spacecraft, which unfortunately exploded after launch. The last of the current steps is COSIMA, a modified CoMA instrument, for

  2. A multi-wavelength scattered light analysis of the dust grain population in the GG Tau circumbinary ring

    SciTech Connect

    Duchene, G; McCabe, C; Ghez, A; Macintosh, B

    2004-02-04

    We present the first 3.8 {micro}m image of the dusty ring surrounding the young binary system GG Tau, obtained with the W. M. Keck II 10m telescope's adaptive optics system. THis is the longest wavelength at which the ring has been detected in scattered light so far, allowing a multi-wavelength analysis of the scattering proiperties of the dust grains present in this protoplanetary disk in combination with previous, shorter wavelengths, HST images. We find that the scattering phase function of the dust grains in the disk is only weakly dependent on the wavelength. This is inconsistent with dust models inferred from observations of the interstellar medium or dense molecular clouds. In particular, the strongly forward-throwing scattering phase function observed at 3.8 {micro}m implies a significant increase in the population of large ({approx}> 1 {micro}m) grains, which provides direct evidence for grain growth in the ring. However, the grain size distribution required to match the 3.8 {micro}m image of the ring is incompatible with its published 1 {micro}m polarization map, implying that the dust population is not uniform throughout the ring. We also show that our 3.8 {micro}m image of the ring is incompatible with its published 1 {micro}m polarization map, implying that the dust population is not uniform throughout the ring. We also show that our 3.8 {micro}m scattered light image probes a deeper layer of the ring than previous shorter wavelength images, as demonstrated by a shift in the location of the inner edge of the disk's scattered light distribution between 1 and 3.8 {micro}m. We therefore propose a stratified structure for the ring in which the surface layers, located {approx} 50 AU above the ring midplane, contain dust grains that are very similar to those found in dense molecular clouds, while the region of the ring located {approx} 25 AU from the midplane contains significantly larger grains. This stratified structure is likely the result of vertical

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

    NASA Technical Reports Server (NTRS)

    Zolensky, M. E.; Bechtel, H. A.; Allen, C.; Bajt, S.; Borg, J.; Brenker, F.; Bridges, J.; Brownlee, D. E.; Burchell, M.; Burghammer, M.; Butterworth, A. L.; Cloetens, P.; Davis, A. M.; Floss, C.; Flynn, G. J.; Frank, D.; Gainsforth, Z.; Grun, E.; Hech, P R.; Hillier, J. K.

    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.

  4. CTEPP STANDARD OPERATING PROCEDURE FOR EXTRACTING AND PREPARING DUST AND SOIL SAMPLES FOR ANALYSIS OF NEUTRAL PERSISTENT ORGANIC POLLUTANTS (SOP-5.14)

    EPA Science Inventory

    This SOP summarizes the method for extracting and preparing a dust or soil sample for analysis of neutral persistent organic pollutants. It covers the extraction and concentration of samples that are to be analyzed by gas chromatography/mass spectrometry.

  5. Laboratory Identity: A Linguistic Landscape Analysis of Personalized Space within a Microbiology Laboratory

    ERIC Educational Resources Information Center

    Hanauer, David I.

    2010-01-01

    This study provides insights into what constitutes a laboratory identity and the ways in which it is spatially constructed. This article explores students' professional identities as microbiologists as manifest in their usage of representational space in a laboratory and as such extends understandings of science identity and spatial identity. The…

  6. Traking of Laboratory Debris Flow Fronts with Image Analysis

    NASA Astrophysics Data System (ADS)

    Queiroz de Oliveira, Gustavo; Kulisch, Helmut; Fischer, Jan-Thomas; Scheidl, Christian; Pudasaini, Shiva P.

    2015-04-01

    Image analysis technique is applied to track the time evolution of rapid debris flow fronts and their velocities in laboratory experiments. These experiments are parts of the project avaflow.org that intends to develop a GIS-based open source computational tool to describe wide spectrum of rapid geophysical mass flows, including avalanches and real two-phase debris flows down complex natural slopes. The laboratory model consists of a large rectangular channel 1.4m wide and 10m long, with adjustable inclination and other flow configurations. The setup allows investigate different two phase material compositions including large fluid fractions. The large size enables to transfer the results to large-scale natural events providing increased measurement accuracy. The images are captured by a high speed camera, a standard digital camera. The fronts are tracked by the camera to obtain data in debris flow experiments. The reflectance analysis detects the debris front in every image frame; its presence changes the reflectance at a certain pixel location during the flow. The accuracy of the measurements was improved with a camera calibration procedure. As one of the great problems in imaging and analysis, the systematic distortions of the camera lens are contained in terms of radial and tangential parameters. The calibration procedure estimates the optimal values for these parameters. This allows us to obtain physically correct and undistorted image pixels. Then, we map the images onto a physical model geometry, which is the projective photogrammetry, in which the image coordinates are connected with the object space coordinates of the flow. Finally, the physical model geometry is rewritten in the direct linear transformation form, which allows for the conversion from one to another coordinate system. With our approach, the debris front position can then be estimated by combining the reflectance, calibration and the linear transformation. The consecutive debris front

  7. Dust particles interaction with plasma jet

    SciTech Connect

    Ticos, C. M.; Jepu, I.; Lungu, C. P.; Chiru, P.; Zaroschi, V.

    2009-11-10

    The flow of plasma and particularly the flow of ions play an important role in dusty plasmas. Here we present some instances in laboratory experiments where the ion flow is essential in establishing dust dynamics in strongly or weakly coupled dust particles. The formation of ion wake potential and its effect on the dynamics of dust crystals, or the ion drag force exerted on micron size dust grains are some of the phenomena observed in the presented experiments.

  8. Analysis of quartz by FT-IR in air samples of construction dust.

    PubMed

    Virji, M Abbas; Bello, Dhimiter; Woskie, Susan R; Liu, X Michael; Kalil, Andrew J

    2002-03-01

    The construction industry is reported to have some of the highest exposures to silica-containing dust. With the designation of crystalline silica as a group I human carcinogen by the International Agency for Research on Cancer (IARC), there exists a need for an analytical method to accurately quantify low levels of quartz. A method is described that uses FT-IR for quartz analysis of personal air samples collected from heavy and highway construction sites using 4-stage personal impactors. Sample filters were ashed and 13-mm or 5-mm pellets were prepared. Absorbance spectra were collected using FT-IR at resolution of 1 cm(-1) and 64 scans per spectrum. Two spectra were collected per sample using the appropriate background spectrum subtraction. Spectral manipulations such as Fourier self-deconvolution and derivatizations were performed to improve quantification. Peak height for quartz was measured at 798 cm(-1) for quantitative analysis. The estimated limit of detection for the 5-mm pellets was 1.3 microg. Recoveries of Min-U-Sil 5 spikes showed an average of > or = 94 percent for the two pellet types. The coefficient of variation of the 5-mm pellet was 9 percent at 6 microg quartz load, and 7 percent at 62 microg load. Interferences from clay, amorphous silica, concrete, calcite, and kaolinite were investigated, these being the more likely sources of interferences in construction environment. Spikes of mixtures of amorphous silica or kaolinite with Min-U-Sil 5 showed both contaminants introduced, on average, a positive error of < 5 microg with average recoveries of 106 percent and 111 percent, respectively. Spikes of mixtures of clay or concrete with Min-U-Sil 5 showed overall average recovery of 100 percent and 90 percent, respectively, after accounting for the presence of quartz in clay and concrete. This method can quantify low levels of quartz with reasonable accuracy in the face of common contaminants found in the construction industry.

  9. Hebes Chasma Dust Avalanches

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    Dust avalanches, also called slope streaks, occur on many Martian terrains. The deposition of airborne dust on surfaces causes a bright tone in the THEMIS VIS images. Any movement of the dust downhill, a dust avalanche, will leave behind a streak where the darker, dust-free surface is exposed.

    These dust avalanches are located in Hebes Chasma.

    Image information: VIS instrument. Latitude -1.4, Longitude 286.6 East (73.4 West). 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  10. Analysis of the dust jet imaged by Rosetta VIRTIS-M in the coma of comet 67P/Churyumov–Gerasimenko on 2015 April 12

    NASA Astrophysics Data System (ADS)

    Tenishev, V.; Fougere, N.; Borovikov, D.; Combi, M. R.; Bieler, A.; Hansen, K. C.; Gombosi, T. I.; Migliorini, A.; Capaccioni, F.; Rinaldi, G.; Filacchione, G.; Kolokolova, L.; Fink, U.

    2016-11-01

    This work is a part of a more global effort aimed at understanding and interpreting in situ and remote sensing data acquired by instruments on board Rosetta. This study aims at deriving the dust mass source rate and the location of the dust jet source observed by Rosetta VIRTIS-M on 2015 April 12. The analysis is performed by means of the coupled kinetic modelling of gas and dust in the coma of comet 67P/Churyumov-Gerasimenko, which were used for calculating the coma brightness as it would be seen from the Rosetta spacecraft. The dust mass production rate and a possible location of the jet origin needed to explain the Rosetta VIRTIS-M dust brightness image were inferred by comparing the calculated brightness with VIRTIS-M data. Our analysis suggests that the dust mass production rate needed to maintain the observed jet is about 1.9 kg s-1. According to our analysis, the location of the observed jet surface footprint is outside of the nucleus area characterized by the highest gas production rate, which suggests that gas and dust source rates are not necessarily proportional to each other across the entire nucleus surface. The inferred location of the possible jet origin is consistent with that of the observed active pits. In this paper, we show that the jet intensity is variable in time, and has a lifetime of at least 10 h.

  11. Particle Lifting Processes in Dust Devils

    NASA Astrophysics Data System (ADS)

    Neakrase, L. D. V.; Balme, M. R.; Esposito, F.; Kelling, T.; Klose, M.; Kok, J. F.; Marticorena, B.; Merrison, J.; Patel, M.; Wurm, G.

    2016-11-01

    Particle lifting in dust devils on both Earth and Mars has been studied from many different perspectives, including how dust devils could influence the dust cycles of both planets. Here we review our current understanding of particle entrainment by dust devils by examining results from field observations on Earth and Mars, laboratory experiments (at terrestrial ambient and Mars-analog conditions), and analytical modeling. By combining insights obtained from these three methodologies, we provide a detailed overview on interactions between particle lifting processes due to mechanical, thermal, electrodynamical and pressure effects, and how these processes apply to dust devils on Earth and Mars. Experiments and observations have shown dust devils to be effective lifters of dust given the proper conditions on Earth and Mars. However, dust devil studies have yet to determine the individual roles of each of the component processes acting at any given time in dust devils.

  12. Dust Avalanches

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Crater wall dust avalanches in southern Arabia Terra.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

    Image information: VIS instrument. Latitude 10.3, Longitude 24.5 East (335.5 West). 19 meter/pixel resolution.

  13. Revisiting the plasma sheath—dust in plasma sheath

    NASA Astrophysics Data System (ADS)

    Das, G. C.; Deka, R.; Bora, M. P.

    2016-04-01

    In this work, we have considered the formation of warm plasma sheath in the vicinity of a wall in a plasma with considerable presence of dust particles. As an example, we have used the parameters relevant in case of plasma sheath formed around surfaces of various solid bodies in space, though the results obtained in this work can be applied to any other physical situation such as laboratory plasma. In the ion-acoustic time scale, we neglect the dust dynamics. The dust particles affect the sheath dynamics by affecting the Poisson equation which determines the plasma potential in the sheath region. It is important to note that our calculations are valid only when the amount of dust particles is not sufficient so as to affect the plasma dynamics in the dust-acoustic time scale, but enough to affect the plasma sheath. We have assumed the current to a dust particle to be balanced throughout the analysis. This makes the grain potential dependent on plasma potential, which is then incorporated into the Poisson equation. The resultant numerical model becomes an initial value problem, which is described by a 1-D integro-differential equation, which is then solved self-consistently by incorporating the change in plasma potential caused by inclusion of the dust potential in the Poisson equation.

  14. Modeling analysis of secondary inorganic aerosols over China: pollution characteristics, and meteorological and dust impacts.

    PubMed

    Fu, Xiao; Wang, Shuxiao; Chang, Xing; Cai, Siyi; Xing, Jia; Hao, Jiming

    2016-10-26

    Secondary inorganic aerosols (SIA) are the predominant components of fine particulate matter (PM2.5) and have significant impacts on air quality, human health, and climate change. In this study, the Community Multiscale Air Quality modeling system (CMAQ) was modified to incorporate SO2 heterogeneous reactions on the surface of dust particles. The revised model was then used to simulate the spatiotemporal characteristics of SIA over China and analyze the impacts of meteorological factors and dust on SIA formation. Including the effects of dust improved model performance for the simulation of SIA concentrations, particularly for sulfate. The simulated annual SIA concentration in China was approximately 10.1 μg/m(3) on domain average, with strong seasonal variation: highest in winter and lowest in summer. High SIA concentrations were concentrated in developed regions with high precursor emissions, such as the North China Plain, Yangtze River Delta, Sichuan Basin, and Pearl River Delta. Strong correlations between meteorological factors and SIA pollution levels suggested that heterogeneous reactions under high humidity played an important role on SIA formation, particularly during severe haze pollution periods. Acting as surfaces for heterogeneous reactions, dust particles significantly affected sulfate formation, suggesting the importance of reducing dust emissions for controlling SIA and PM2.5 pollution.

  15. Modeling analysis of secondary inorganic aerosols over China: pollution characteristics, and meteorological and dust impacts

    NASA Astrophysics Data System (ADS)

    Fu, Xiao; Wang, Shuxiao; Chang, Xing; Cai, Siyi; Xing, Jia; Hao, Jiming

    2016-10-01

    Secondary inorganic aerosols (SIA) are the predominant components of fine particulate matter (PM2.5) and have significant impacts on air quality, human health, and climate change. In this study, the Community Multiscale Air Quality modeling system (CMAQ) was modified to incorporate SO2 heterogeneous reactions on the surface of dust particles. The revised model was then used to simulate the spatiotemporal characteristics of SIA over China and analyze the impacts of meteorological factors and dust on SIA formation. Including the effects of dust improved model performance for the simulation of SIA concentrations, particularly for sulfate. The simulated annual SIA concentration in China was approximately 10.1 μg/m3 on domain average, with strong seasonal variation: highest in winter and lowest in summer. High SIA concentrations were concentrated in developed regions with high precursor emissions, such as the North China Plain, Yangtze River Delta, Sichuan Basin, and Pearl River Delta. Strong correlations between meteorological factors and SIA pollution levels suggested that heterogeneous reactions under high humidity played an important role on SIA formation, particularly during severe haze pollution periods. Acting as surfaces for heterogeneous reactions, dust particles significantly affected sulfate formation, suggesting the importance of reducing dust emissions for controlling SIA and PM2.5 pollution.

  16. Modeling analysis of secondary inorganic aerosols over China: pollution characteristics, and meteorological and dust impacts

    PubMed Central

    Fu, Xiao; Wang, Shuxiao; Chang, Xing; Cai, Siyi; Xing, Jia; Hao, Jiming

    2016-01-01

    Secondary inorganic aerosols (SIA) are the predominant components of fine particulate matter (PM2.5) and have significant impacts on air quality, human health, and climate change. In this study, the Community Multiscale Air Quality modeling system (CMAQ) was modified to incorporate SO2 heterogeneous reactions on the surface of dust particles. The revised model was then used to simulate the spatiotemporal characteristics of SIA over China and analyze the impacts of meteorological factors and dust on SIA formation. Including the effects of dust improved model performance for the simulation of SIA concentrations, particularly for sulfate. The simulated annual SIA concentration in China was approximately 10.1 μg/m3 on domain average, with strong seasonal variation: highest in winter and lowest in summer. High SIA concentrations were concentrated in developed regions with high precursor emissions, such as the North China Plain, Yangtze River Delta, Sichuan Basin, and Pearl River Delta. Strong correlations between meteorological factors and SIA pollution levels suggested that heterogeneous reactions under high humidity played an important role on SIA formation, particularly during severe haze pollution periods. Acting as surfaces for heterogeneous reactions, dust particles significantly affected sulfate formation, suggesting the importance of reducing dust emissions for controlling SIA and PM2.5 pollution. PMID:27782166

  17. Heliocentric trajectory analysis of Sun-pointing smart dust with electrochromic control

    NASA Astrophysics Data System (ADS)

    Mengali, Giovanni; Quarta, Alessandro A.

    2016-02-01

    A smart dust is a micro spacecraft, with a characteristic side length on the order of a few millimeters, whose surface is coated with electrochromic material. Its orbital dynamics is controlled by exploiting the differential force due to the solar radiation pressure, which is obtained by modulating the reflectivity coefficient of the electrochromic material within a range of admissible values. A significant thrust level can be reached due to the high values of area-to-mass ratio of such a spacecraft configuration. Assuming that the smart dust is designed to achieve a passive Sun-pointing attitude, the propulsive acceleration due to the solar radiation pressure lies along the Sun-spacecraft direction. The aim of this paper is to study the smart dust heliocentric dynamics in order to find a closed form, analytical solution of its trajectory when the reflectivity coefficient of the electrochromic material can assume two values only. The problem is addressed by introducing a suitable transformation that regularizes the spacecraft motion and translates the smart-dust dynamics into that of a linear harmonic oscillator with unitary frequency, whose forcing input is a boxcar function. The solution is found using the Laplace transform method, and afterwards the problem is generalized by accounting for the degradation of the electrochromic material due to its exposition to the solar radiation. Three spacecraft configurations, corresponding to low, medium and high performance smart dusts, are finally used to quantify the potentialities of these advanced devices in an interplanetary mission scenario.

  18. Radiative transfer with POLARIS. I. Analysis of magnetic fields through synthetic dust continuum polarization measurements

    NASA Astrophysics Data System (ADS)

    Reissl, S.; Wolf, S.; Brauer, R.

    2016-09-01

    Aims: We present POLARIS (POLArized RadIation Simulator), a newly developed three-dimensional Monte-Carlo radiative transfer code. POLARIS was designed to calculate dust temperature, polarization maps, and spectral energy distributions. It is optimized to handle data that results from sophisticated magneto-hydrodynamic simulations. The main purpose of the code is to prepare and analyze multi-wavelength continuum polarization measurements in the context of magnetic field studies in the interstellar medium. An exemplary application is the investigation of the role of magnetic fields in star formation processes. Methods: We combine currently discussed state-of-the-art grain alignment theories with existing dust heating and polarization algorithms. We test the POLARIS code on multiple scales in complex astrophysical systems that are associated with different stages of star formation. POLARIS uses the full spectrum of dust polarization mechanisms to trace the underlying magnetic field morphology. Results: Resulting temperature distributions are consistent with the density and position of radiation sources resulting from magneto-hydrodynamic (MHD) - collapse simulations. The calculated layers of aligned dust grains in the considered cirumstellar disk models are in excellent agreement with theoretical predictions. Finally, we compute unique patterns in synthetic multi-wavelength polarization maps that are dependent on applied dust-model and grain-alignment theory in analytical cloud models.

  19. Electrodynamic Dust Shield Demonstrator

    NASA Technical Reports Server (NTRS)

    Stankie, Charles G.

    2013-01-01

    The objective of the project was to design and manufacture a device to demonstrate a new technology developed by NASA's Electrostatics and Surface Physics Laboratory. The technology itself is a system which uses magnetic principles to remove regolith dust from its surface. This project was to create an enclosure that will be used to demonstrate the effectiveness of the invention to The Office of the Chief Technologist. ONE of the most important challenges of space exploration is actually caused by something very small and seemingly insignificant. Dust in space, most notably on the moon and Mars, has caused many unforeseen issues. Dirt and dust on Earth, while a nuisance, can be easily cleaned and kept at bay. However, there is considerably less weathering and erosion in space. As a result, the microscopic particles are extremely rough and abrasive. They are also electrostatically charged, so they cling to everything they make contact with. This was first noted to be a major problem during the Apollo missions. Dust would stick to the spacesuits, and could not be wiped off as predicted. Dust was brought back into the spacecraft, and was even inhaled by astronauts. This is a major health hazard. Atmospheric storms and other events can also cause dust to coat surfaces of spacecraft. This can cause abrasive damage to the craft. The coating can also reduce the effectiveness of thermal insulation and solar panels.' A group of engineers at Kennedy Space Center's Electrostatics and Surface Physics Laboratory have developed a new technology, called the Electrodynamic Dust Shield, to help alleviate these problems. It is based off of the electric curtain concept developed at NASA in 1967. "The EDS is an active dust mitigation technology that uses traveling electric fields to transport electrostatically charged dust particles along surfaces. To generate the traveling electric fields, the EDS consists of a multilayer dielectric coating with an embedded thin electrode grid

  20. Electrophoretic gel image analysis software for the molecular biology laboratory.

    PubMed

    Redman, T; Jacobs, T

    1991-06-01

    We present GelReader 1.0, a microcomputer program designed to make precision, digital analysis of one-dimensional electrophoretic gels accessible to the molecular biology laboratory of modest means. Images of electrophoretic gels are digitized via a desktop flatbed scanner from instant photographs, autoradiograms or chromogenically stained blotting media. GelReader is then invoked to locate lanes and bands and generate a report of molecular weights of unknowns, based on specified sets of standards. Frequently used standards can be stored in the program. Lanes and bands can be added or removed, based upon users' subjective preferences. A unique lane histogram feature facilitates precise manual addition of bands missed by the software. Image enhancement features include palette manipulation, histogram equalization, shadowing and magnification. The user interface strikes a balance between program autonomy and user intervention, in recognition of the variability in electrophoretic gel quality and users' analytical needs.

  1. Cardiorespiratory fitness and laboratory stress: a meta-regression analysis.

    PubMed

    Jackson, Erica M; Dishman, Rod K

    2006-01-01

    We performed a meta-regression analysis of 73 studies that examined whether cardiorespiratory fitness mitigates cardiovascular responses during and after acute laboratory stress in humans. The cumulative evidence indicates that fitness is related to slightly greater reactivity, but better recovery. However, effects varied according to several study features and were smallest in the better controlled studies. Fitness did not mitigate integrated stress responses such as heart rate and blood pressure, which were the focus of most of the studies we reviewed. Nonetheless, potentially important areas, particularly hemodynamic and vascular responses, have been understudied. Women, racial/ethnic groups, and cardiovascular patients were underrepresented. Randomized controlled trials, including naturalistic studies of real-life responses, are needed to clarify whether a change in fitness alters putative stress mechanisms linked with cardiovascular health.

  2. Analysis of search in an online clinical laboratory manual.

    PubMed

    Blechner, Michael; Kish, Joshua; Chadaga, Vivek; Dighe, Anand S

    2006-08-01

    Online laboratory manuals have developed into an important gateway to the laboratory. Clinicians increasingly expect up-to-date laboratory test information to be readily available online. During the past decade, sophisticated Internet search technology has developed, permitting rapid and accurate retrieval of a wide variety of content. We studied the role of search in an online laboratory manual. We surveyed the utilization of search technology in publicly available online manuals and examined how users interact with the search feature of a laboratory handbook. We show how a laboratory can improve its online handbook through insights gained by collecting information about each user's activity. We also discuss future applications for search-related technologies and the potential role of the online laboratory manual as the primary laboratory information portal.

  3. ROSETTA/COSIMA at comet 67P/Churyumov-Gerasimenko - 2 years of in-situ dust analysis

    NASA Astrophysics Data System (ADS)

    Schulz, Rita; Hilchenbach, Martin; Kissel, Jochen; Langevin, Yves; Briois, Christelle; Koch, Andreas; Silen, Johan; Baklouti, Donia; Bardyn, Anais; Cottin, Herve'; Engrand, Cecile; Fischer, Henning; Fray, Nicolas; Glasmachers, Albrecht; Gruen, Eberhard; Haerendel, Gerhard; Henkel, Hartmut; Höfner, Hervig; Hornung, Klaus; Jessberger, Elmar; Lehto, Harry J.; Letho, Kirsi; Ligier, Nicolas; Merouane, Sihane; Orthous-Daunay, Francois-Regis; Paquette, John; Raulin, F.; Le Roy, Léna; Rynö, Jouni; Siljeström, Sandra; Steiger, Wolfgang; Stenzel, Oliver; Stephan, Thomas; Thirkell, Laurent; Thomas, Roger; Torkar, Klaus; Varmuza, Kurt; Wanczek, Karl-Peter; Zaprudin, Boris

    2016-10-01

    In August 2014 the ROSETTA spacecraft rendezvoused with comet 67P/Churyumov-Gerasimenko and escorted it for more than 2 years along its orbit around the Sun from 4 AU preperihelion to 4 AU postperihelion. During this time the COSIMA instrument (COmetary Secondary Ion Mass Analyser) onboard ROSETTA collected more than 25,000 dust particles in the vicinity of the comet nucleus. All these particles were collected on a number of specially designed metal target plates which were regularly imaged with a microscope (14 µm pixel/pixel resolution, 14mm x 14mm FOV) enabling the analysis of their individual morphologies, certain physical properties, e.g. tensile strength, albedo, as well as the overall flux and size distribution of the dust entering the COSIMA instrument. The images were also used to choose which of the particles shall go through compositional measurements with the time-of-flight mass spectrometer (sometimes repeated at a later time). All these investigations were done over 2 years. This allows to study the compositional and morphological differences of the particles collected at the various sections of the pre- and postperihelion orbit, the evolution of the morphology of the particles on the target plate with time, and the search for spatial heterogeneity of the composition within a particle by taking mass spectra at different locations on the same particle. An overview will be given on the available data and the results obtained so far in view to the analysis of dust composition and morphology, as well as dust flux and size distribution along the orbit.

  4. DUSTER (Dust in the Upper Stratosphere Tracking Experiment and Retrieval) . PRELIMINARY ANALYSIS

    NASA Astrophysics Data System (ADS)

    Ciucci, A.; Palumbo, P.; Brunetto, R.; Della Corte, V.; De Angelis, S.; Rotundi, A.; Rietmeijer, F. J. M.; Zona, E.; Colangeli, L.; Esposito, F.; Mazzotta Epifani, E.; Mennella, V.; Inarta, S.; Peterzen, S.; Masi, S.; Ibba, R.

    The DUSTER project is aimed at uncontaminated collection and retrieval of stratospheric solid aerosol particles, in the submicron/micron range. The Earth stratosphere contains extraterrestrial dust, dust from natural and anthropogenic activities. Our main target is the study of dust originated in our planetary system. We present here the preliminary results of the June 2008 campaign. After recovery, collected particles were identified by comparing FESEM images taken on the pre-flight collector with those obtained on the post-fight collector. Possible contamination was monitored by FESEM observation of the 'Blank'. Morphology, dimension, and composition of collected particles were defined using a FESEM equipped with an EDX system. The collected sample are in the size range 0.5-150 μm, ≈30% of aerosols sizing 0.5-1.5 μm, a range poorly studied so far.

  5. Particle size effect for metal pollution analysis of atmospherically deposited dust

    NASA Astrophysics Data System (ADS)

    Al-Rajhi, M. A.; Al-Shayeb, S. M.; Seaward, M. R. D.; Edwards, H. G. M.

    The metallic compositions of 231 atmospherically deposited dust samples obtained from widely-differing environments in Riyadh city, Saudi Arabia, have been investigated in relation to the particle size distributions. Sample data are presented which show that particle size classification is very important when analysing dust samples for atmospheric metal pollution studies. By cross-correlation and comparison, it was found that the best way to express the results of the metal concentration trend was as an average of particle ratios. Correlations between the six metals studied, namely Pb, Cr, Ni, Cu, Zn and Li, were found for every particle size (eight categories) and reveal that the metal concentrations increased as the particle size decreased. On the basis of this work, it is strongly recommended that future international standards for metal pollutants in atmospherically deposited dusts should be based on particle size fractions.

  6. Quality of HIV laboratory testing in Tanzania: a situation analysis.

    PubMed

    Mfinanga, G S; Mutayoba, B; Mbogo, G; Kahwa, A; Kimaro, G; Mhame, P P; Mwangi, C; Malecela, M N; Kitua, A Y

    2007-01-01

    Tanzania is scaling up prevention, treatment, care and support of individuals affected with HIV. There is therefore a need for high quality and reliable HIV infection testing and AIDS staging. The objective of this study was to assess laboratories capacities of services in terms of HIV testing and quality control. A baseline survey was conducted from December 2004 to February 2005 in 12 laboratories which were conveniently selected to represent all the zones of Tanzania. The questionnaires comprised of questions on laboratory particulars, internal and external quality control for HIV testing and quality control of reagents. Source and level of customer satisfaction of HIV test kits supply was established. Of 12 laboratories, nine used rapid tests for screening and two used rapid tests for diagnosis. In the 12 laboratories, four used double ELISA and five used single ELISA and three did not use ELISA. Confirmatory tests observed were Western Blot in three laboratories, DNA PCR in two laboratories, CD4 counting in seven laboratories, and viral load in two laboratories. Although all laboratories conducted quality control (QC) of the HIV kits, only two laboratories had Standard Operating Procedures (SOPs). Internal and external quality control (EQC) was done at varied proportions with the highest frequency of 55.6% (5/9) for internal quality control (IQC) for rapid tests and EQC for ELISA, and the lowest frequency of 14.3% (1/ 7) for IQC for CD4 counting. None of the nine laboratories which conducted QC for reagents used for rapid tests and none of the five which performed IQC and EQC had SOPs. HIV kits were mainly procured by the Medical Store Department and most of laboratories were not satisfied with the delay in procurement procedures. Most of the laboratories used rapid tests only, while some used both rapid tests and ELISA method for HIV testing. In conclusion, the survey revealed inadequacy in Good Laboratory Practice and poor laboratory quality control process

  7. The Laboratory Structure and Task Analysis Inventory (LAI): A Users' Handbook. Technical Report No. 14.

    ERIC Educational Resources Information Center

    Fuhrman, M.; And Others

    The Laboratory Structure and Task Analysis Inventory (LAI) is an instrument designed to facilitate the analysis of laboratory investigations in secondary school science. It yields a quantitative picture of the kinds of activities required of a student in performing laboratory investigations. The report includes guidelines for the use of the…

  8. Statistical Analysis Tools for Learning in Engineering Laboratories.

    ERIC Educational Resources Information Center

    Maher, Carolyn A.

    1990-01-01

    Described are engineering programs that have used automated data acquisition systems to implement data collection and analyze experiments. Applications include a biochemical engineering laboratory, heat transfer performance, engineering materials testing, mechanical system reliability, statistical control laboratory, thermo-fluid laboratory, and a…

  9. Thermodynamic analysis of the selective carbothermic reduction of electric arc furnace dust.

    PubMed

    Pickles, C A

    2008-01-31

    Electric arc furnace (EAF) dust, which is produced as a result of the melting of automobile scrap in an electric arc furnace, contains considerable amounts of zinc and lead, which are of significant economic value. Typically, the other major components are iron oxide and calcium oxide with minor amounts of other metal oxides. In this research, a detailed thermodynamic study of the pyrometallurgical processing of the dust, using carbon as a reducing agent was performed. The SOLGASMIX solver of Outokumpu HSC Chemistry((R)) 5.1 was used to calculate the equilibrium composition under reducing conditions. The control input dust composition was as follows (in mass percent): 8.100% CaO, 8.250% 2CaO.SiO(2), 11.200% CaCO(3), 8.830% CaO.Fe(2)O(3), 7.840% Fe(3)O(4), 3.770% PbO, 38.150% ZnFe(2)O(4) and 13.860% ZnO. Selective reduction and separation of both the zinc and the lead as metallic vapours, from the iron, in oxide form, was examined. The separation of the zinc or the lead from the iron, was defined quantitatively in terms of the selectivity factor (logbeta) as follows. Equation [see the text] where the subscript symbols refer to the metal being present in gaseous (g), metallic solid (m), solid oxide (o) or metallic liquid (l) form, respectively. The standard calculations were performed for one hundred grams of dust at atmospheric pressure. The variables investigated were as follows; temperature in the range of 1273-1873K, reactant ratio (i.e. moles of carbon per gram of dust), dust composition, addition of inert gas and reduced total pressure. The calculated values were in reasonable agreement with those from previously published studies and also industrial results.

  10. Capability of the Gas Analysis and Testing Laboratory at the NASA Johnson Space Center

    NASA Technical Reports Server (NTRS)

    Broerman, Craig; Jimenez, Javier; Sweterlitsch, Jeff

    2012-01-01

    The Gas Analysis and Testing Laboratory is an integral part of the testing performed at the NASA Johnson Space Center. The Gas Analysis and Testing Laboratory is a high performance laboratory providing real time analytical instruments to support manned and unmanned testing. The lab utilizes precision gas chromatographs, gas analyzers and spectrophotometers to support the technology development programs within the NASA community. The Gas Analysis and Testing Laboratory works with a wide variety of customers and provides engineering support for user-specified applications in compressed gas, chemical analysis, general and research laboratory.

  11. Capability of the Gas Analysis and Testing Laboratory at the NASA Johnson Space Center

    NASA Technical Reports Server (NTRS)

    Broerman, Craig; Jimenez, Javier; Sweterlitsch, Jeff

    2011-01-01

    The Gas Analysis and Testing Laboratory is an integral part of the testing performed at the NASA Johnson Space Center. The Gas Analysis and Testing Laboratory is a high performance laboratory providing real time analytical instruments to support manned and unmanned testing. The lab utilizes precision gas chromatographs, gas analyzers and spectrophotometers to support the technology development programs within the NASA community. The Gas Analysis and Testing Laboratory works with a wide variety of customers and provides engineering support for user-specified applications in compressed gas, chemical analysis, general and research laboratory

  12. China Dust

    Atmospheric Science Data Center

    2013-04-16

    ... SpectroRadiometer (MISR) nadir-camera images of eastern China compare a somewhat hazy summer view from July 9, 2000 (left) with a ... arid and sparsely vegetated surfaces of Mongolia and western China pick up large quantities of yellow dust. Airborne dust clouds from the ...

  13. Martian Dust Simulator

    NASA Technical Reports Server (NTRS)

    Zuray, Monica; Houston, Karrie; Lorentson, Chris

    2008-01-01

    The Martian Dust Simulator (MDS) was designed to investigate the contamination effects of Martian soil and rock on the performance and function of flight-like microvalves and flight-like filters located within the Sample Analysis at Mars (SAM) instrument suite. The SAM instrument suite, which houses over fifty percent of the science payload, is located on-board the Mars exploration rover. The mission objective of the Mars Science Laboratory Rover is to determine the past, present, and future habitability of Mars. It will serve as a robot geologist, traveling the Mars surface for a period of one Martian year (equivalent to two earth years). The microvalves were designed as a conduit to control the flow of Martian gas to the science instruments. If exposed to particle sizes greater than half a micron, both the science instruments and science equipment, including forty-seven microvalves, could experience performance degradation. As a result, filters were used at various gas inlets to protect flight hardware from particulate degradation. Additionally, the filters serve as the only interface between the Martian environment and the mechanisms within SAM. The MDS operates at 7 Torr (0.135 psi) with a gas flow rate of 0 to 20 m/s. Iron (III) Oxide was the only dust particle specimen used, although several others were initially considered (i.e. JSC-Mars-1, Corundum Powder (Al2O3), Hydrated Sulfate, and Belville (Basalt)). The overarching goal of the MDS is to demonstrate that the Mars exploration program is adequately designed and prepared for the Martian mission environment.

  14. Andromeda's dust

    SciTech Connect

    Draine, B. T.; Aniano, G.; Krause, Oliver; Groves, Brent; Sandstrom, Karin; Klaas, Ulrich; Linz, Hendrik; Rix, Hans-Walter; Schinnerer, Eva; Schmiedeke, Anika; Walter, Fabian; Braun, Robert; Leroy, Adam E-mail: ganiano@ias.u-psud.fr

    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.

  15. Deuterated glycoaldehyde: laboratory measurements, analysis and proposed astrophysical research

    NASA Astrophysics Data System (ADS)

    Walters, A.; Bouchez, A.; Margules, L.; Motiyenko, R.; Guillemin, J. C.; Bottinelli, S.; Ceccarelli, C.; Kahane, C.

    2011-05-01

    We have measured in the laboratory the spectra of all the monosubstituted isotopologues of glycoaldehyde (CH_2OD-CHO, CHDOH-CHO, CH_2OH-CDO) and one doubly substituted one (CHDOH-CDO). The spectra were measured, between 150 and 630 GHz, with the new Lille submillimetre-wave spectrometer based on harmonic generation of solid-state sources. The samples were provided by Rennes. Apart from the first listed isotopologue all species were observed simultaneously in the presence of an intense spectral impurity (pyridine), which complicated assignment. This work is part of the FORCOMS project, funded by the French National Research Agency (ANR) that concerns the Formation of Complex Organic Molecules (COMs) in Space. The goal of the project is to better understand the formation of these COMs during the earliest phases of star formation. Glycoaldehyde, a sugar-related interstellar prebiotic molecule has been detected in two star-forming regions, Sgr B2(N) (1,2) and G31.41+0.31(3). A significant overabundance of deuterated species has been observed in protostellar environments. Formation of glycoaldehyde is suspected to involve photodissociation driven ice chemistry. One of the objectives of FORCOMS is to test if a comparison of the abundance of deuterated and non-deuterated COMs can be used to trace complex organic chemistry in interstellar environments. Previous laboratory work on the D-isotopologues was restricted to less than 26 GHz (4). We hence carried out new measurements and analysis to obtain a complete set of predictions for radioastronomy. The previous measurements greatly helped in assigning the spectra. Simulations with CASSIS software have been made to select the best candidates for detection and a telescope proposal is under way.

  16. Analysis of the spatial distribution of stars, gas and dust in nearby galaxies

    NASA Astrophysics Data System (ADS)

    Muñoz-Mateos, J. C.

    2013-05-01

    I summarize the main result of my thesis, which was awarded the Spanish Astronomical Society Award for the best thesis in Astronomy defended in 2010. This thesis was supervised by Armando Gil de Paz and Jaime Zamorano at Universidad Complutense de Madrid. In this work we quantified how the physical properties of stars, gas and dust vary with radius in nearby galactic disks, and used that information to infer the past assembly and evolution of galaxies. To do so we made use of spatially-resolved multi-wavelength images of nearby galaxies, all the way from the far-UV to the far-IR and radio. By comparing extinction- corrected profiles in the UV, optical and IR with models of disk evolution, we concluded that the current stellar population gradients are consistent with an inside-out growth of disks of ˜ 25% since z ˜ 1. We also found that the dust-to-gas ratio decreases with radius, and is tightly correlated with the local gas metallicity, which is again consistent with an inside-out assembly of disks. We measured the fraction of the dust mass which is in the form of PAHs at different radii. The resulting trend agrees with certain models of dust evolution, in which the abundance of PAHs is primarily determined by a delayed injection of carbon into the ISM by AGB stars.

  17. The Will to Conservation: A Burkeian Analysis of Dust Bowl Rhetoric and American Farming Motives.

    ERIC Educational Resources Information Center

    Peterson, Tarla Rai

    1986-01-01

    Analyzes the rhetoric of agricultural conservationists focusing on the 1930s Dust Bowl, revealing that its potential for promoting environmentally sound land-use practices was limited. Argues that the vulnerability of conservation efforts to competing forces was largely a function of the hierarchy of motives associated with land use. (SRT)

  18. Stardust Interstellar Preliminary Examination III: Infrared spectroscopic analysis of interstellar dust candidates

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

    Under the auspices of the Stardust Interstellar Preliminary Examination, picokeystones extracted from the Stardust Interstellar Dust Collector were examined with synchrotron Fourier transform infrared (FTIR) microscopy to establish whether they contained extraterrestrial organic material. The picokeystones were found to be contaminated with varying concentrations and speciation of organics in the native aerogel, which hindered the search for organics in the interstellar dust candidates. Furthermore, examination of the picokeystones prior to and post X-ray microprobe analyses yielded evidence of beam damage in the form of organic deposition or modification, particularly with hard X-ray synchrotron X-ray fluorescence. From these results, it is clear that considerable care must be taken to interpret any organics that might be in interstellar dust particles. For the interstellar candidates examined thus far, however, there is no clear evidence of extraterrestrial organics associated with the track and/or terminal particles. However, we detected organic matter associated with the terminal particle in Track 37, likely a secondary impact from the Al-deck of the sample return capsule, demonstrating the ability of synchrotron FTIR to detect organic matter in small particles within picokeystones from the Stardust interstellar dust collector.

  19. The formation of a large summertime Saharan dust plume: Convective and synoptic-scale analysis.

    PubMed

    Roberts, A J; Knippertz, P

    2014-02-27

    Haboobs are dust storms produced by the spreading of evaporatively cooled air from thunderstorms over dusty surfaces and are a major dust uplift process in the Sahara. In this study observations, reanalysis, and a high-resolution simulation using the Weather Research and Forecasting model are used to analyze the multiscale dynamics which produced a long-lived (over 2 days) Saharan mesoscale convective system (MCS) and an unusually large haboob in June 2010. An upper level trough and wave on the subtropical jet 5 days prior to MCS initiation produce a precipitating tropical cloud plume associated with a disruption of the Saharan heat low and moistening of the central Sahara. The restrengthening Saharan heat low and a Mediterranean cold surge produce a convergent region over the Hoggar and Aïr Mountains, where small convective systems help further increase boundary layer moisture. Emerging from this region the MCS has intermittent triggering of new cells, but later favorable deep layer shear produces a mesoscale convective complex. The unusually large size of the resulting dust plume (over 1000 km long) is linked to the longevity and vigor of the MCS, an enhanced pressure gradient due to lee cyclogenesis near the Atlas Mountains, and shallow precipitating clouds along the northern edge of the cold pool. Dust uplift processes identified are (1) strong winds near the cold pool front, (2) enhanced nocturnal low-level jet within the aged cold pool, and (3) a bore formed by the cold pool front on the nocturnal boundary layer.

  20. The formation of a large summertime Saharan dust plume: Convective and synoptic-scale analysis

    PubMed Central

    Roberts, A J; Knippertz, P

    2014-01-01

    Haboobs are dust storms produced by the spreading of evaporatively cooled air from thunderstorms over dusty surfaces and are a major dust uplift process in the Sahara. In this study observations, reanalysis, and a high-resolution simulation using the Weather Research and Forecasting model are used to analyze the multiscale dynamics which produced a long-lived (over 2 days) Saharan mesoscale convective system (MCS) and an unusually large haboob in June 2010. An upper level trough and wave on the subtropical jet 5 days prior to MCS initiation produce a precipitating tropical cloud plume associated with a disruption of the Saharan heat low and moistening of the central Sahara. The restrengthening Saharan heat low and a Mediterranean cold surge produce a convergent region over the Hoggar and Aïr Mountains, where small convective systems help further increase boundary layer moisture. Emerging from this region the MCS has intermittent triggering of new cells, but later favorable deep layer shear produces a mesoscale convective complex. The unusually large size of the resulting dust plume (over 1000 km long) is linked to the longevity and vigor of the MCS, an enhanced pressure gradient due to lee cyclogenesis near the Atlas Mountains, and shallow precipitating clouds along the northern edge of the cold pool. Dust uplift processes identified are (1) strong winds near the cold pool front, (2) enhanced nocturnal low-level jet within the aged cold pool, and (3) a bore formed by the cold pool front on the nocturnal boundary layer. PMID:25844277

  1. QUANTITATIVE PCR ANALYSIS OF HOUSE DUST CAN REVEAL ABNORMAL MOLD CONDITIONS

    EPA Science Inventory

    Indoor mold populations were measured in the dust of homes in Cleveland and Cincinnati, OH, by quantitative PCR (QPCR) and, in Cincinnati, also by culturing. QPCR assays for 82 species (or groups of species) were used to identify and quantify indoor mold populations in moldy home...

  2. QUANTITATIVE PCR ANALYSIS OF FUNGI IN DUST FROM HOMES OF INFANTS WHO DEVELOPED IDIOPATHIC PULMONARY HEMORRHAGING

    EPA Science Inventory

    Fungal concentrations were measured in the dust of six homes in Cleveland, OH, where a child developed pulmonary hemorrhage (pulmonary hemorrhage homes, i.e. PHH), and 26 reference homes (RH) with no known fungal contamination. QPCR assays for 82 species (or assay groups) were u...

  3. Fertilization potential of volcanic dust in the low-nutrient low-chlorophyll western North Pacific subtropical gyre: Satellite evidence and laboratory study

    NASA Astrophysics Data System (ADS)

    Lin, I.-I.; Hu, Chuanmin; Li, Yuan-Hui; Ho, Tung-Yuan; Fischer, Tobias P.; Wong, George T. F.; Wu, Jingfeng; Huang, Chih-Wei; Chu, D. Allen; Ko, Dong S.; Chen, Jen-Ping

    2011-03-01

    In the western North Pacific subtropical ocean, the Anatahan volcano of the Mariana Islands erupted on 10 May 2003 for the first time in recorded history. Based on nine different types of remote sensing data provided by NASA, laboratory experiment of the Anatahan samples, and a 3-D ocean circulation model developed by the U.S. Naval Research Laboratory, the postvolcanic ocean biogeochemical response to the Anatahan eruption was explored. It was observed that soon after the eruption, the aerosol optical depth abruptly increased from the pre-eruption loading of ˜0.1 to ˜2. In the week following the eruption, a "bloom-like" patch was observed by NASA's Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) ocean color sensor. Based on the chlorophyll a, fluorescence line height (FLH), at-sensor total radiance, and normalized water-leaving radiance data obtained by MODIS, the cause of the bloom-like patch was diagnosed. The results suggest that the patch was most likely a mixture of suspended volcanic particles and a phytoplankton bloom. FLH was found to be ˜9-17 × 10-3 mW cm-2μm-1 sr-1 in the patch and ˜3-5 × 10-3 mW cm-2μm-1 sr-1 in the ambient water, indicating that a 2-5-fold increase in biological activity occurred during the week following the eruption. Satellite altimetry indicated that the bloom took place in the presence of downwelling and was not a result of upwelled nutrients in this oligotrophic ocean. Analysis of satellite ocean color spectra of the bloom region found similar spectra as the reference Trichodesmium spectra. Laboratory experiments further substantiate the satellite observations which show elevated concentrations of limiting nutrients provided by the Anatahan samples, and the averaged soluble nitrate, phosphate, and Fe were 42, 3.1, and 2.0 nM, respectively. Though it was not possible to obtain in situ observations of the ocean biogeochemical responses that followed the Anatahan eruption, this study provided evidence based on

  4. Nutritional requirements and contaminant analysis of laboratory animal feeds

    SciTech Connect

    Pal, B.C.; Ross, R.H.; Milman, H.A.

    1984-05-01

    The primary objectives of this report are to present information concerning the nutritional requirements of several commonly used laboratory animal species (i.e., mouse, rat, hamster, guinea pig, rabbit, and dog) and to discuss various aspects of the problem of contamination of laboratory animal feeds. In addition, this document discusses the different types of laboratory animal diets (e.g., open vs closed formula), the ingredients used in these diets, the interaction of dietary components, and the public comments received respective to the EPA proposed guidelines for the nutrient composition of laboratory animal diets. Much of the data are presented in tabular form. 567 references; 3 figures; 19 tables; 5 appendices.

  5. Information Management Systems in the Undergraduate Instrumental Analysis Laboratory.

    ERIC Educational Resources Information Center

    Merrer, Robert J.

    1985-01-01

    Discusses two applications of Laboratory Information Management Systems (LIMS) in the undergraduate laboratory. They are the coulometric titration of thiosulfate with electrogenerated triiodide ion and the atomic absorption determination of calcium using both analytical calibration curve and standard addition methods. (JN)

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

    SciTech Connect

    Bryan, Charles R.; Enos, David

    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

  7. Design and development of a dust dispersion chamber to quantify the dispersibility of rock dust.

    PubMed

    Perera, Inoka E; Sapko, Michael J; Harris, Marcia L; Zlochower, Isaac A; Weiss, Eric S

    2016-01-01

    Dispersible rock dust must be applied to the surfaces of entries in underground coal mines in order to inert the coal dust entrained or made airborne during an explosion and prevent propagating explosions. 30 CFR. 75.2 states that "… [rock dust particles] when wetted and dried will not cohere to form a cake which will not be dispersed into separate particles by a light blast of air …" However, a proper definition or quantification of "light blast of air" is not provided. The National Institute for Occupational Safety and Health (NIOSH) has, consequently, designed a dust dispersion chamber to conduct quantitative laboratory-scale dispersibility experiments as a screening tool for candidate rock dusts. A reproducible pulse of air is injected into the chamber and across a shallow tray of rock dust. The dust dispersed and carried downwind is monitored. The mass loss of the dust tray and the airborne dust measurements determine the relative dispersibility of the dust with respect to a Reference rock dust. This report describes the design and the methodology to evaluate the relative dispersibility of rock dusts with and without anti-caking agents. Further, the results of this study indicate that the dispersibility of rock dusts varies with particle size, type of anti-caking agent used, and with the untapped bulk density. Untreated rock dusts, when wetted and dried forming a cake that was much less dispersible than the reference rock dust used in supporting the 80% total incombustible content rule.

  8. Using Dust from Asteroids as Regolith Microsamples

    NASA Technical Reports Server (NTRS)

    Cohen, B. A.; Klima, Rachel; Chabot, N. L.; Rivkin, A. S.

    2015-01-01

    Meteorite science is rich with compositional indicators by which we classify parent bodies, but few sample groups are definitively linked with asteroid spectra. More robust links need to be forged between meteorites and their parent bodies to understand the composition, diversity and distribution. A major link can be sample analysis of the parent body material and comparison with meteorite data. Hayabusa, the first sample return mission of the Japanese Aerospace Exploration Agency (JAXA), was developed to rendezvous with and collect samples from asteroid Itokawa and return them to Earth. Thousands of sub-100 micron particles were recovered, apparently introduced during the spacecraft impact into the surface of the asteroid, linking the asteroid Itokawa to LL chondrites [1]. Upcoming missions Hayabusa 2 and OSIRIS-REx will collect more significant sample masses from asteroids. In all these cases, the samples are or will be a collection of regolith particles. Sample return to earth is not the only method for regolith particle analysis. Dust is present around all airless bodies, generated by micrometeorite impact into their airless surfaces, which in turn lofts regolith particles into a "cloud" around the body. The composition, flux, and size-frequency distribution of dust particles can provide significant insight into the geological evolution of airless bodies [2]. For example, the Cassini Cosmic Dust Analyzer (CDA) detected salts in Enceladus' icy plume material, providing evidence for a subsurface ocean in contact with a silicate seafloor [3]. Similar instruments have flown on the Rosetta, LADEE, and Stardust missions. Such an instrument may be of great use in obtaining the elemental, isotopic and mineralogical composition measurement of dust particles originating from asteroids without returning the samples to terrestrial laboratories. We investigated the ability of a limited sample analysis capability using a dust instrument to forge links between asteroid

  9. Analysis of Physical Properties of Dust Suspended in the Mars Atmosphere

    NASA Technical Reports Server (NTRS)

    Snook, Kelly; McKay, Chris; Cantwell, Brian

    1998-01-01

    Methods for iteratively determining the infrared optical constants for dust suspended in the Mars atmosphere are described. High quality spectra for wavenumbers from 200 to 2000 1/cm were obtained over a wide range of view angles by the Mariner 9 spacecraft, when it observed a global Martian dust storm in 1971-2. In this research, theoretical spectra of the emergent intensity from Martian dust clouds are generated using a 2-stream source-function radiative transfer code. The code computes the radiation field in a plane-parallel, vertically homogeneous, multiply scattering atmosphere. Calculated intensity spectra are compared with the actual spacecraft data to iteratively retrieve the optical properties and opacity of the dust, as well as the surface temperature of Mars at the time and location of each measurement. Many different particle size distributions a-re investigated to determine the best fit to the data. The particles are assumed spherical and the temperature profile was obtained from the CO2 band shape. Given a reasonable initial guess for the indices of refraction, the searches converge in a well-behaved fashion, producing a fit with error of less than 1.2 K (rms) to the observed brightness spectra. The particle size distribution corresponding to the best fit was a lognormal distribution with a mean particle radius, r(sub m) 0.66 pm, and variance, omega(sup 2) = 0.412 (r(sub eff) = 1.85 microns, v(sub eff) =.51), in close agreement with the size distribution found to be the best fit in the visible wavelengths in recent studies. The optical properties and the associated single scattering properties are shown to be a significant improvement over those used in existing models by demonstrating the effects of the new properties both on heating rates of the Mars atmosphere and in example spectral retrieval of surface characteristics from emission spectra.

  10. The mini-CIDEX GC/IMS: Analysis of cometary ice and dust

    NASA Technical Reports Server (NTRS)

    Kojiro, Daniel R.; Carle, Glenn C.; Humphry, Donald E.; Shao, Maxine; Takeuchi, Nori

    1995-01-01

    Comets are recognized as among the most scientifically important objects in the solar system. They are presumed relics of the early primitive material in the solar nebula and are believed to have provided a general enrichment of volatiles to the inner solar system. The Cometary Coma Chemical Composition (C4) Mission, a proposed Discovery-Class Mission, will analyze materials released into the coma, providing information leading to the understanding of the chemical composition and make-up of the cometary nucleus. As one of two scientific instruments in the C4 spacecraft, an advanced and streamlined version of the Cometary Ice and Dust Experiment (CIDEX), a mini-CIDEX, will employ an X-Ray Fluorescence (XRF) spectrometer to determine bulk elemental composition of cometary dust grains and a Gas Chromatograph/Ion Mobility Spectrometer (GC/IMS) for determination of the molecular composition of dust and ices following stepwise pyrolysis and combustion. A description of the mini-CIDEX IMS will be provided as well as data from analyses conducted using the mini-CIDEX breadboard instrument.

  11. Analysis of dust samples from urban and rural occupational environments in Croatia.

    PubMed

    Macan, Jelena; Kanceljak-Macan, Bozica; Mustac, Marko; Milković-Kraus, Sanja

    2005-12-01

    This study estimated the exposure to dust mites in various occupational environments in Croatia. In total, 29 occupational dust samples were collected: 10 from urban areas (offices, archive of an insurance company, tobacco, paper-recycling, fish-processing and textile plants, animal unit for experimental rats, winery), nine from rural areas (barley, hay, animal food and flour warehouses, tailor's shops, wood processing plant, swine confinement house, grocer's storeroom), and 10 samples from cabins of five fishing boats (five floor and five bed samples). Mites were microscopically identified, and the levels of Der p 1, Der f 1, and Der 2 allergens measured using the DUSTSCREEN test (Heska AG, Switzerland). Microscopy showed no mites in urban areas. Pyroglyphid mites (D. pteronyssinus) were found in all bed samples from fishing boats. Non-pyroglyphid mites were found in samples taken from barley, hay and animal food warehouses, the swine confinement house, grocer's storeroom, and fishing boats. Pyroglyphid mite allergens were detected in eight of 10 dust samples from the fishing boats. Median levels of Der p 1, Der f 1, and Der 2 in cabin bed samples were 10 microg g(-1), 0.2 microg g(-1), and 3.5 microg g(-1), respectively. Our findings on fishing boats suggests that pyroglyphid mites could be considered work-related allergens for fishermen. The results of this study confirmed non-pyroglyphid mites as occupational risk factors in various rural environments.

  12. Photoelectric Charging of Dust Particles

    NASA Technical Reports Server (NTRS)

    Sickafoose, A.; Colwell, J.; Horanyi, M.; Robertson, S.; Walch, B.

    1999-01-01

    Laboratory experiments have been performed on the photoelectric charging of dust particles which are either isolated or adjacent to a surface that is also a photoemitter. We find that zinc dust charges to a positive potential of a few volts when isolated in vacuum and that it charges to a negative potential of a few volts when passed by a photoemitting surface. The illumination is an arc lamp emitting wavelengths longer than 200 nm and the emitting surface is a zirconium foil.

  13. Food and Drug Administration: Laboratory Analysis of Product Samples needs to be more Timely.

    DTIC Science & Technology

    1986-09-01

    protect the American consumer from adulterated or misbranded (vio- lative) products. The role of FDA’s field laboratories in accomplishing this... adulterated or misbranded products from the market is the timely processing of products through the laboratory. FDA has not given its laboratories... adulterated or misbranded products reaching the market. GAo’s analysis showed that the laboratories took an average of 28 calendar days to complete product

  14. Dust That's Worth Keeping

    SciTech Connect

    Hazi, A

    2006-01-25

    Images taken of interstellar space often display a colorful canvas of portions of the electromagnetic spectrum. Dispersed throughout the images are interstellar clouds of dust and gas--remnants ejected from stars and supernovae over billions and billions of years. For more than 40 years, astronomers have observed that interstellar dust exhibits a consistent effect at a spectral wavelength of 2,175 angstroms, the equivalent of 5.7 electronvolts in energy on the electromagnetic spectrum. At this wavelength, light from stars is absorbed by dust in the interstellar medium, blocking the stars light from reaching Earth. The 2,175-angstrom feature, which looks like a bump on spectra, is the strongest ultraviolet-visible light spectral signature of interstellar dust and is visible along nearly every observational line of sight. Scientists have sought to solve the mystery of what causes the 2,175-angstrom feature by reproducing the effect in the laboratory. They speculated a number of possibilities, including fullerenes (buckyballs), nanodiamonds, and even interstellar organisms. However, none of these materials fits the data for the unique spectral feature. Limitations in the energy and spatial resolution achievable with electron microscopes and ion microprobes--the two main instruments used to study samples of dust--have also prevented scientists from finding the answer. A collaborative effort led by Livermore physicist John Bradley and funded by the National Aeronautics and Space Administration (NASA) has used a new-generation transmission electron microscope (TEM) and nanoscale ion microprobe to unlock the mystery. The Livermore group includes physicists Zu Rong Dai, Ian Hutcheon, Peter Weber, and Sasa Bajt and postdoctoral researchers Hope Ishii, Giles Graham, and Julie Smith. They collaborated with the University of California at Davis (UCD), Lawrence Berkeley National Laboratory, Washington University's Laboratory for Space Sciences in St. Louis, and NASA's Ames

  15. Dust That's Worth Keeping

    NASA Technical Reports Server (NTRS)

    Hazi, A.

    2006-01-01

    Images taken of interstellar space often display a colorful canvas of portions of the electromagnetic spectrum. Dispersed throughout the images are interstellar clouds of dust and gas--remnants ejected from stars and supernovae over billions and billions of years. For more than 40 years, astronomers have observed that interstellar dust exhibits a consistent effect at a spectral wavelength of 2,175 angstroms, the equivalent of 5.7 electronvolts in energy on the electromagnetic spectrum. At this wavelength, light from stars is absorbed by dust in the interstellar medium, blocking the stars light from reaching Earth. The 2,175-angstrom feature, which looks like a bump on spectra, is the strongest ultraviolet-visible light spectral signature of interstellar dust and is visible along nearly every observational line of sight. Scientists have sought to solve the mystery of what causes the 2,175-angstrom feature by reproducing the effect in the laboratory. They speculated a number of possibilities, including fullerenes (buckyballs), nanodiamonds, and even interstellar organisms. However, none of these materials fits the data for the unique spectral feature. Limitations in the energy and spatial resolution achievable with electron microscopes and ion microprobes--the two main instruments used to study samples of dust--have also prevented scientists from finding the answer. A collaborative effort led by Livermore physicist John Bradley and funded by the National Aeronautics and Space Administration (NASA) has used a new-generation transmission electron microscope (TEM) and nanoscale ion microprobe to unlock the mystery. The Livermore group includes physicists Zu Rong Dai, Ian Hutcheon, Peter Weber, and Sasa Bajt and postdoctoral researchers Hope Ishii, Giles Graham, and Julie Smith. They collaborated with the University of California at Davis (UCD), Lawrence Berkeley National Laboratory, Washington University's Laboratory for Space Sciences in St. Louis, and NASA's Ames

  16. Dust Removal on Mars Using Laser-Induced Breakdown Spectroscopy

    NASA Technical Reports Server (NTRS)

    Graff, T. G.; Morris, R. V.; Clegg, S. M.; Wiens, R. C.; Anderson, R. B.

    2011-01-01

    Dust coatings on the surface of Mars complicate and, if sufficiently thick, mask the spectral characteristics and compositional determination of underlying material from in situ and remote sensing instrumentation. The Laser-Induced Breakdown Spectroscopy (LIBS) portion of the Chemistry & Camera (ChemCam) instrument, aboard the Mars Science Laboratory (MSL) rover, will be the first active remote sensing technique deployed on Mars able to remove dust. ChemCam utilizes a 5 ns pulsed 1067 nm high-powered laser focused to less than 400 m diameter on targets at distances up to 7 m [1,2]. With multiple laser pulses, dust and weathering coatings can be remotely analyzed and potentially removed using this technique [2,3]. A typical LIBS measurement during MSL surface operations is planned to consist of 50 laser pulses at 14 mJ, with the first 5 to 10 pulses used to analyze as well as remove any surface coating. Additionally, ChemCam's Remote Micro-Imager (RMI) is capable of resolving 200 m details at a distance of 2 m, or 1 mm at 10 m [1,4]. In this study, we report on initial laboratory experiments conducted to characterize the removal of dust coatings using similar LIBS parameters as ChemCam under Mars-like conditions. These experiments serve to better understand the removal of surface dust using LIBS and to facilitate the analysis of ChemCam LIBS spectral data and RMI images.

  17. Relationships between coal properties and respirable dust generation potential

    SciTech Connect

    Srikanth, R.; Zhao, R.; Ramani, R.V.

    1995-12-31

    A two-part study was conducted to understand the factors affecting respirable dust generation potential or dustiness of coal seams. In the first part, the data from three prior comprehensive laboratory studies was analyzed to establish quantitative relationships between respirable dust generation potential and coal characteristics. This analysis indicates that respirable dust generation rate is positively correlated with Hardgrove Grindability Index. (HGI), fuel ratio (fixed carbon/volatile matter), Vitrinite Reflectance (VR), and Level of Organic Metamorphism (LOM). In the second part, specially-designed single breakage experiments were conducted to determine the primary dust generation potential of 17 coal samples obtained from four continuous miner sections, three longwall sections, and the Penn State Coal Data Bank. The single breakage study indicates that primary dust generation rate is positively correlated with fixed carbon content, fuel ratio (fixed carbon/volatile matter), VR, and LOM. Since VR and LOM are strongly influenced by the process of coalification, differences in respirable dust generation rates in different coal seams may be explained by the thermal metamorphism of sedimentary organic matter during subsurface burial.

  18. Dust in the Wind: Modern and Ancient Dust Compositions

    NASA Astrophysics Data System (ADS)

    Hummer, P. J.; Pierce, J. L.; Benner, S. G.

    2013-12-01

    The addition of wind-blown sediments to soils can alter soil grain-size distributions, chemistry, and hydrologic properties, which can substantially affect geomorphic and hydrologic processes. In the Snake River Plain of Idaho, dust deposition has a profound influence on soil development, soil fertility and other soil characteristics. A rigorous study of the movement and chemistry of dust in the Boise area has not been completed. This study will establish a sampling method for dust collection, define the elemental signature of Boise dust and analyze Quaternary loess deposits to determine if the composition of dust in the Boise area has changed. We constructed passive marble samplers to collect wind-blown sediments within the Dry Creek Experimental Watershed (DCEW) located in the Boise Front foothills about 16 km northeast of Boise, Idaho. Mass flux amounts and the mineralogical composition of dust samples will provide information about the influence of wind-blown sediments on the soils of Dry Creek Experimental Watershed. ICP-MS analysis of samples will define an elemental signature for Boise dust. Comparison of modern dust with ancient loess will improve the understanding of the role of climate change in dust transport. We analyzed hourly wind speed data collected over the past 10 years from three weather stations to investigate trends in the timing of peak wind events. Average annual wind speeds range from 1.29 to 4.91 mph with a total average of 2.82 mph. Analysis of wind speeds indicate that while the majority of the highest wind events occur in the winter, wind events that occur during the summer months may be responsible for transporting dust. Recent large dust storms may have originated from extensive burned rangelands, and/or large plowed agricultural land. Future work will investigate the percentages of organic vs. inorganic material in loess, in order to narrow down possible sources of dust in the Snake River Plain.

  19. Probing The Stellar, Gaseous, And Dust Properties Of Galaxies Through Analysis Of Their Spectral Energy Distributions

    NASA Astrophysics Data System (ADS)

    Eufrasio, Rafael T.

    The spectral energy distributions (SEDs) of galaxies are shaped by their physical properties and they are our primary source of information on galaxies stellar, gaseous, and dust content. Nearby galaxies (less than 100 Mpc away) are spatially resolved by current telescopes from the ultraviolet (UV) to radio wavelengths, allowing the study of the SEDs of subgalactic regions. Such studies are necessary for deriving maps and spatial trends of the physical properties across a galaxy. In principle, the complex history of the formation, growth, and evolution of a galaxy or a region of a galaxy can be inferred from its radiative output. In practice, this task is complicated by the fact that a significant fraction of the star formation activity takes place in dust obscured regions, in which a significant fraction of the stellar radiative output is absorbed, scattered, and reradiated by the gas and dust in the interstellar medium (ISM). This reprocessing of the stellar radiation takes place in ionized interstellar gas regions (H II regions) surrounding massive hot stars, in diffuse atomic gas (H I regions), and in dense molecular clouds. For this work, we have analyzed two galaxies in detail, NGC 6872 and NGC 6946, also known as Condor and Fireworks Galaxy, respectively. The Condor galaxy is the largest-known spiral galaxy. It is part a group of galaxies, the Pavo group, with 12 other galaxies. It has, however, interacted in the past ~150 Myr with a smaller companion, previously believed to have shaped the physical extent of the giant spiral. We have performed detailed SED fitting from the UV to mid-infrared (mid-IR) to obtain star formation histories of seventeen sub-galactic regions across the Condor. These regions are large enough to be galaxies themselves, with 32.3 million light-years in diameter. We find that the Condor was already very massive before this interaction and that it was much less affected by the passage of the companion than previously thought. We also

  20. Picatinny Arsenal 3000 Area Laboratory Complex Energy Analysis

    SciTech Connect

    Brown, Daryl R.; Goddard, James K.

    2010-05-01

    In response to a request by Picatinny Arsenal, the Pacific Northwest National Laboratory (PNNL) was asked by the Army to conduct an energy audit of the Arsenal’s 3000 Area Laboratory Complex. The objective of the audit was to identify life-cycle cost-effective measures that the Arsenal could implement to reduce energy costs. A “walk-through” audit of the facilities was conducted on December 7-8, 2009. Findings and recommendations are included in this document.

  1. Scattering by interstellar graphite dust analog

    NASA Astrophysics Data System (ADS)

    Ahmed, Gazi A.; Gogoi, Ankur

    2014-10-01

    The analysis of optical scattering data of interstellar carbonaceous graphite dust analog at 543.5 nm, 594.5 nm and 632.8 nm laser wavelengths by using an original laboratory light scattering setup is presented. The setup primarily consisted of a laser source, optical units, aerosol sprayer, data acquisition system and associated instrumentation. The instrument measured scattered light signals from 10° to 170° in steps of 1°. The results of the measurements of the volume scattering function β(θ) and degree of linear polarization P(θ) of the carbonaceous graphite dust particles that were sprayed in front of the laser beam by using an aerosol sprayer were subsequently compared with theoretically generated Mie plots with estimated parameters.

  2. Characterization of wood dust from furniture by scanning electron microscopy and energy-dispersive x-ray analysis.

    PubMed

    Gómez Yepes, Milena Elizabeth; Cremades, Lázaro V

    2011-01-01

    Study characterized and analyzed form factor, elementary composition and particle size of wood dust, in order to understand its harmful health effects on carpenters in Quindío (Colombia). Once particle characteristics (size distributions, aerodynamic equivalent diameter (D(α)), elemental composition and shape factors) were analyzed, particles were then characterized via scanning electron microscopy (SEM) in conjunction with energy dispersive X-ray analysis (EDXRA). SEM analysis of particulate matter showed: 1) cone-shaped particle ranged from 2.09 to 48.79 µm D(α); 2) rectangular prism-shaped particle from 2.47 to 72.9 µm D(α); 3) cylindrically-shaped particle from 2.5 to 48.79 µm D(α); and 4) spherically-shaped particle from 2.61 to 51.93 µm D(α). EDXRA reveals presence of chemical elements from paints and varnishes such as Ca, K, Na and Cr. SEM/EDXRA contributes in a significant manner to the morphological characterization of wood dust. It is obvious that the type of particles sampled is a complex function of shapes and sizes of particles. Thus, it is important to investigate the influence of particles characteristics, morphology, shapes and D(α) that may affect the health of carpenters in Quindío.

  3. Tikhonravov Crater Dust Avalanches

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    Dust avalanches, also called slope streaks, occur on many Martian terrains. The deposition of airborne dust on surfaces causes a bright tone in the THEMIS VIS images. Any movement of the dust downhill, a dust avalanche, will leave behind a streak where the darker, dust-free surface is exposed.

    These dust avalanches are located within a small crater inside Tikhonravov Crater.

    Image information: VIS instrument. Latitude 12.6, Longitude 37.1 East (322.9 West). 36 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  4. Lycus Sulci Dust Avalanches

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    Dust avalanches, also called slope streaks, occur on many Martian terrains. The deposition of airborne dust on surfaces causes a bright tone in the THEMIS VIS images. Any movement of the dust downhill, a dust avalanche, will leave behind a streak where the darker, dust-free surface is exposed.

    These dust avalanches occur on the slopes of Lycus Sulci near Olympus Mons.

    Image information: VIS instrument. Latitude 28.1, Longitude 220.4 East (139.6 West). 18 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  5. Crater Dust Avalanches

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    Dust avalanches, also called slope streaks, occur on many Martian terrains. The deposition of airborne dust on surfaces causes a bright tone in the THEMIS VIS images. Any movement of the dust downhill, a dust avalanche, will leave behind a streak where the darker, dust-free surface is exposed.

    These dust avalanches are located in a small canyon within a crater rim northeast of Naktong Vallis.

    Image information: VIS instrument. Latitude 7.1, Longitude 34.7 East (325.3 West). 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  6. Crater Dust Avalanches

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    Dust avalanches, also called slope streaks, occur on many Martian terrains. The deposition of airborne dust on surfaces causes a bright tone in the THEMIS VIS images. Any movement of the dust downhill, a dust avalanche, will leave behind a streak where the darker, dust-free surface is exposed.

    This region of dust avalanches is located in and around a crater to the west of yesterday's image.

    Image information: VIS instrument. Latitude 14.7, Longitude 32.7 East (327.3 West). 18 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  7. The Organic Component of Interstellar Dust

    NASA Technical Reports Server (NTRS)

    Pendleton, Yvonne

    2003-01-01

    The distribution, chemical structure, and formation of organic matter in the interstellar medium are important to our understanding of the overall evolution of dust. The exchange of dust between the dense and diffuse interstellar medium, and the effects of processing on dust within dense clouds will affect the inventory of material available for incorporation into newly forming star and planetary systems. Observational ground-based studies have confirmed the widespread distribution of the 3.4 pm absorption band attributed to aliphatic hydrocarbons in the diffuse interstellar medium of our own galaxy, and in the dusty spectra of a few nearby galaxies, while space based observations from IS0 probed the signatures of corresponding mid-infrared features. Laboratory experiments which utilize both thermal processes and energetic processing by high energy photons and cosmic rays, produce candidate materials which offer close matches to the observed diffuse interstellar medium and extragalactic hydrocarbon absorption features. Through an analysis of the 4000 to 1000 cm (2.5 to 10 micrometers) region of the spectrum of diffuse interstellar medium (DISM) dust compared with the spectra of thirteen chemical entities produced in the laboratory which serve as analogs to the interstellar material, significant constraints have been placed on the applicability of proposed candidate materials to explain the interstellar features. The results indicate that the organic refractory material in the diffuse interstellar medium is predominantly hydrocarbon in nature, possessing little nitrogen or oxygen, with the carbon distributed between the aromatic and aliphatic forms. Long alkane chains H3C-(CH2),- with n much greater than 4 or 5 are not major constituents of this material. Comparisons to laboratory analogs indicate the DISM organic material resembles plasma processed pure hydrocarbon residues much more so than energetically processed ice residues. This result is consistent with a

  8. The dusty nova V1065 centauri (nova cen 2007) : a spectroscopic analysis of abundances and dust properties.

    SciTech Connect

    Helton, L. A.; Woodward, C. E.; Walter, F. M.; Vanlandingham, K.; Schwarz, G. J.; Evans, A.; Ness, J.-U.; Geballe, T. R.; Gehrz, R. D.; Greenhouse, M.; Krautter, J.; Liller, W.; Lynch, D. K.; Rudy, R. J.; Shore, S. N.; Starrfield, S.; Truran, J.

    2010-10-14

    We examine the ejecta evolution of the classical nova V1065 Centauri, constructing a detailed picture of the system based on spectrophotometric observations obtained from 9 to approximately 900 days post-outburst with extensive coverage from optical to mid-infrared wavelengths. We estimate a reddening toward the system of E(B-V) = 0.5 {+-} 0.1, based upon the B-V color and analysis of the Balmer decrement, and derive a distance estimate of 8.7{sub -2.1}{sup +2.8} kpc. The optical spectral evolution is classified as P{sub fe}{sup o} N{sub ne}A{sub 0} according to the CTIO Nova Classification system of Williams et al. Photoionization modeling yields absolute abundance values by number, relative to solar of He/H = 1.6 {+-} 0.3, N/H = 144 {+-} 34, O/H = 58 {+-} 18, and Ne/H = 316 {+-} 58 for the ejecta. We derive an ejected gas mass of M{sub g} = (1.6 {+-} 0.2) x 10{sup -4} M{circle_dot}. The infrared excess at late epochs in the evolution of the nova arises from dust condensed in the ejecta composed primarily of silicate grains. We estimate a total dust mass, Md , of order (0.2-3.7) x 10{sup -7} M{circle_dot}, inferred from modeling the spectral energy distribution observed with the Spitzer IRS and Gemini-South GNIRS spectrometers. Based on the speed class, neon abundance, and the predominance of silicate dust, we classify V1065 Cen as an ONe-type classical nova.

  9. Sahara Dust Cloud

    NASA Technical Reports Server (NTRS)

    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

  10. Cotton dust, endotoxin and cancer mortality among the Shanghai textile workers cohort: a 30-year analysis

    PubMed Central

    Fang, S C; Mehta, A J; Hang, J Q; Eisen, E A; Dai, H L; Zhang, H X; Su, L; Christiani, D C

    2013-01-01

    Background Although occupational exposure to cotton dust and endotoxin is associated with adverse respiratory health, associations with cancer are unclear. We investigated cancer mortality in relation to cotton dust and endotoxin exposure in the Shanghai textile workers cohort. Methods We followed 444 cotton textile and a reference group of 467 unexposed silk workers for 30 years (26 777 person-years). HRs for all cancers combined (with and without lung cancer) and gastrointestinal cancer were estimated in Cox regression models as functions of cotton textile work and categories of cumulative exposure (low, medium, high), after adjustment for covariates including pack-years smoked. Different lag years accounted for disease latency. Results Risks of mortality from gastrointestinal cancers and all cancers combined, with the exclusion of lung cancer, were increased in cotton workers relative to silk workers. When stratified by category of cumulative cotton exposure, in general, risks were greatest for 20-year lagged medium exposure (all cancers HR=2.7 (95% CI 1.4 to 5.2); cancer excluding lung cancer HR=3.4 (1.7–7.0); gastrointestinal cancer HR=4.1 (1.8–9.7)). With the exclusion of lung cancer, risks of cancer were more pronounced. When stratified by category of cumulative endotoxin exposure, consistent associations were not observed for all cancers combined. However, excluding lung cancer, medium endotoxin exposure was associated with all cancers and gastrointestinal cancer in almost all lag models. Conclusions Cotton dust may be associated with cancer mortality, especially gastrointestinal cancer, and endotoxin may play a causative role. Findings also indirectly support a protective effect of endotoxin on lung cancer. PMID:23828454

  11. Asian Dust at Mauna Loa Observatory: Analysis and Modeling of Individual Atmospheric Particles

    NASA Astrophysics Data System (ADS)

    Conny, J. M.; Willis, R. D.; Ortiz-Montalvo, D. L.

    2015-12-01

    Springtime Asian dust storms events, typically originating in the Gobi Desert or Taklamakan Desert, produce particles that can be carried aloft eastward for thousands of miles. As a result, the radiative properties of these particles can significantly affect global climate. Here, we determine the optical properties of particles identified as Asian dust at Mauna Loa Observatory, Hawaii, (MLO) based on the composition and actual shapes of individual particles. Samples of particulate material <10 μm in size were collected at MLO, between March 15 and April 26, 2011. Air mass back trajectories and satellite imagery showed that a subset of the aerosol sampled during this period likely originated from the Asian mainland while most of the aerosol probably did not. Samples were first analyzed by automated scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry, whereby particles were sorted into compositionally-distinct particle types. Two particle types, identified as dolomite and calcite were determined to have originated from Asia. A third type, anhydrite, also aloft in the free troposphere, was not associated with Asian dust. Individual particles were analyzed compositionally and their shapes modeled spatially using focused ion-beam (FIB) SEM and FIB tomography. Particle 3-D representations were then input to the discrete dipole approximation method to determine their optical properties for 589 nm light. Calculations revealed that the single scattering albedo (SSA) for the Asian dust particles (0.79 to 0.94) straddled the critical SSA for cooling vs. warming (0.86), with the lowest SSA (0.79) attributed to a small amount of soot (1.7 % by volume) attached to a dolomite particle. SSA for the free troposphere anhydrite particles (0.90 to 0.93) was well above the critical SSA. For the three particle types, SSA for the actual-shaped particles was higher than equivalently-sized spheres, cubes, or tetrahedra. For the fraction of backscattered light from

  12. Dust emission parameterization scheme over the MENA region: Sensitivity analysis to soil moisture and soil texture

    NASA Astrophysics Data System (ADS)

    Gherboudj, Imen; Beegum, S. Naseema; Marticorena, Beatrice; Ghedira, Hosni

    2015-10-01

    The mineral dust emissions from arid/semiarid soils were simulated over the MENA (Middle East and North Africa) region using the dust parameterization scheme proposed by Alfaro and Gomes (2001), to quantify the effect of the soil moisture and clay fraction in the emissions. For this purpose, an extensive data set of Soil Moisture and Ocean Salinity soil moisture, European Centre for Medium-Range Weather Forecasting wind speed at 10 m height, Food Agricultural Organization soil texture maps, MODIS (Moderate Resolution Imaging Spectroradiometer) Normalized Difference Vegetation Index, and erodibility of the soil surface were collected for the a period of 3 years, from 2010 to 2013. Though the considered data sets have different temporal and spatial resolution, efforts have been made to make them consistent in time and space. At first, the simulated sandblasting flux over the region were validated qualitatively using MODIS Deep Blue aerosol optical depth and EUMETSAT MSG (Meteosat Seciond Generation) dust product from SEVIRI (Meteosat Spinning Enhanced Visible and Infrared Imager) and quantitatively based on the available ground-based measurements of near-surface particulate mass concentrations (PM10) collected over four stations in the MENA region. Sensitivity analyses were performed to investigate the effect of soil moisture and clay fraction on the emissions flux. The results showed that soil moisture and soil texture have significant roles in the dust emissions over the MENA region, particularly over the Arabian Peninsula. An inversely proportional dependency is observed between the soil moisture and the sandblasting flux, where a steep reduction in flux is observed at low friction velocity and a gradual reduction is observed at high friction velocity. Conversely, a directly proportional dependency is observed between the soil clay fraction and the sandblasting flux where a steep increase in flux is observed at low friction velocity and a gradual increase is

  13. Coordinated Stem and NanoSIMS Analysis of Enstatite Whiskers in Interplanetary Dust Particles

    NASA Technical Reports Server (NTRS)

    Nakamura-Messenger, K.; Messenger, Scott; Keller, L. P.

    2009-01-01

    Enstatite whiskers (less than 10 micrometer length, less than 200 nanometer width) occur in chondritic-porous interplanetary dust particles (CP IDPs), an Antarctic micrometeorite and a comet 81P/Wild-2 sample. The whiskers are typically elongated along the [100] axis and contain axial screw dislocations, while those in terrestrial rocks and meteorites are elongated along [001]. The unique crystal morphologies and microstructures are consistent with the enstatite whiskers condensing above approximately 1300 K in a low-pressure nebular or circumstellar gas. To constrain the site of enstatite whisker formation, we carried out coordinated mineralogical, chemical and oxygen isotope measurements on enstatite whiskers in a CP IDP.

  14. 10 CFR 707.12 - Specimen collection, handling and laboratory analysis for drug testing.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Specimen collection, handling and laboratory analysis for drug testing. 707.12 Section 707.12 Energy DEPARTMENT OF ENERGY WORKPLACE SUBSTANCE ABUSE PROGRAMS AT DOE SITES Procedures § 707.12 Specimen collection, handling and laboratory analysis for drug...

  15. 10 CFR 707.12 - Specimen collection, handling and laboratory analysis for drug testing.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Specimen collection, handling and laboratory analysis for drug testing. 707.12 Section 707.12 Energy DEPARTMENT OF ENERGY WORKPLACE SUBSTANCE ABUSE PROGRAMS AT DOE SITES Procedures § 707.12 Specimen collection, handling and laboratory analysis for drug...

  16. 10 CFR 707.12 - Specimen collection, handling and laboratory analysis for drug testing.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Specimen collection, handling and laboratory analysis for drug testing. 707.12 Section 707.12 Energy DEPARTMENT OF ENERGY WORKPLACE SUBSTANCE ABUSE PROGRAMS AT DOE SITES Procedures § 707.12 Specimen collection, handling and laboratory analysis for drug...

  17. 10 CFR 707.12 - Specimen collection, handling and laboratory analysis for drug testing.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Specimen collection, handling and laboratory analysis for drug testing. 707.12 Section 707.12 Energy DEPARTMENT OF ENERGY WORKPLACE SUBSTANCE ABUSE PROGRAMS AT DOE SITES Procedures § 707.12 Specimen collection, handling and laboratory analysis for drug...

  18. 10 CFR 707.12 - Specimen collection, handling and laboratory analysis for drug testing.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Specimen collection, handling and laboratory analysis for drug testing. 707.12 Section 707.12 Energy DEPARTMENT OF ENERGY WORKPLACE SUBSTANCE ABUSE PROGRAMS AT DOE SITES Procedures § 707.12 Specimen collection, handling and laboratory analysis for drug...

  19. QUALITY ASSURANCE GUIDELINES FOR LABORATORIES PERFORMING FORENSIC ANALYSIS OF CHEMICAL TERRORISM

    EPA Science Inventory

    The Scientific Working Group on Forensic Analysis of Chemical Terrorism (SWGFACT) has developed the following quality assurance guidelines to provide laboratories engaged in forensic analysis of chemical evidence associated with terrorism a framework to implement a quality assura...

  20. Crew Exploration Vehicle (CEV) Avionics Integration Laboratory (CAIL) Independent Analysis

    NASA Technical Reports Server (NTRS)

    Davis, Mitchell L.; Aguilar, Michael L.; Mora, Victor D.; Regenie, Victoria A.; Ritz, William F.

    2009-01-01

    Two approaches were compared to the Crew Exploration Vehicle (CEV) Avionics Integration Laboratory (CAIL) approach: the Flat-Sat and Shuttle Avionics Integration Laboratory (SAIL). The Flat-Sat and CAIL/SAIL approaches are two different tools designed to mitigate different risks. Flat-Sat approach is designed to develop a mission concept into a flight avionics system and associated ground controller. The SAIL approach is designed to aid in the flight readiness verification of the flight avionics system. The approaches are complimentary in addressing both the system development risks and mission verification risks. The following NESC team findings were identified: The CAIL assumption is that the flight subsystems will be matured for the system level verification; The Flat-Sat and SAIL approaches are two different tools designed to mitigate different risks. The following NESC team recommendation was provided: Define, document, and manage a detailed interface between the design and development (EDL and other integration labs) to the verification laboratory (CAIL).

  1. A new laboratory approach to shale analysis using NMR relaxometry

    USGS Publications Warehouse

    Washburn, Kathryn E.; Birdwell, Justin E.; Baez, Luis; Beeney, Ken; Sonnenberg, Steve

    2013-01-01

    Low-field nuclear magnetic resonance (LF-NMR) relaxometry is a non-invasive technique commonly used to assess hydrogen-bearing fluids in petroleum reservoir rocks. Measurements made using LF-NMR provide information on rock porosity, pore-size distributions, and in some cases, fluid types and saturations (Timur, 1967; Kenyon et al., 1986; Straley et al., 1994; Brown, 2001; Jackson, 2001; Kleinberg, 2001; Hurlimann et al., 2002). Recent improvements in LF-NMR instrument electronics have made it possible to apply methods used to measure pore fluids to assess highly viscous and even solid organic phases within reservoir rocks. T1 and T2 relaxation responses behave very differently in solids and liquids; therefore the relationship between these two modes of relaxation can be used to differentiate organic phases in rock samples or to characterize extracted organic materials. Using T1-T2 correlation data, organic components present in shales, such as kerogen and bitumen, can be examined in laboratory relaxometry measurements. In addition, implementation of a solid-echo pulse sequence to refocus T2 relaxation caused by homonuclear dipolar coupling during correlation measurements allows for improved resolution of solid-phase protons. LF-NMR measurements of T1 and T2 relaxation time distributions were carried out on raw oil shale samples from the Eocene Green River Formation and pyrolyzed samples of these shales processed by hydrous pyrolysis and techniques meant to mimic surface and in-situ retorting. Samples processed using the In Situ Simulator approach ranged from bitumen and early oil generation through to depletion of petroleum generating potential. The standard T1-T2 correlation plots revealed distinct peaks representative of solid- and liquid-like organic phases; results on the pyrolyzed shales reflect changes that occurred during thermal processing. The solid-echo T1 and T2 measurements were used to improve assessment of the solid organic phases, specifically

  2. Self-attenuation artifacts and correction factors of light element measurements by X-ray analysis: Implication for mineral dust composition studies

    NASA Astrophysics Data System (ADS)

    Formenti, P.; Nava, S.; Prati, P.; Chevaillier, S.; Klaver, A.; Lafon, S.; Mazzei, F.; Calzolai, G.; Chiari, M.

    2010-01-01

    On a global scale, mineral dust is one of the major components of atmospheric aerosols and has important effects on the radiative budget of the atmosphere and thus on climate forcing. An accurate measurement of the concentration of crustal elements, namely Na, Mg, Al, Si, K, Ca, Ti, and Fe, is mandatory for the study of desert aerosols. The concentration of light elements, when measured by X-ray emission techniques such as X-ray fluorescence (XRF) and particle-induced X-ray emission (PIXE), can be underestimated owing to self-absorption of the emitted soft X-rays inside aerosol particles. In this work, we analyzed dust samples collected in field campaigns and samples produced in the laboratory using dust of known composition. Measurements have been conducted with PIXE and energy-dispersive XRF (ED-XRF), together with an attenuation-free technique such as particle-induced gamma-ray emission (PIGE) and attenuation corrected wavelength-dispersive XRF (WD-XRF) by internal standard calibration. We focus on the determination of Al and present results of a PIXE versus PIGE intercomparison. Aluminum concentration was measured with both techniques in dust samples collected by aircraft sampling over western Africa during winter 2006 and summer 2007. An underestimation of the Al concentration determined by PIXE was observed (up to 40%), and it was compared with the results of a simple calculation using basic physics and the size distribution of the collected aerosol. Similar attenuation was observed for Mg, Al, and Si in the laboratory samples analyzed by ED-XRF and WD-XRF. In order to use concentration ratios involving light elements as tracers of the region of emission of the sampled dust, these artifacts (i.e., underestimation of the concentration of light elements) induced by self-attenuation should be properly considered and corrected.

  3. Potential of laser mass spectrometry for the analysis of environmental dust particles--a review.

    PubMed

    Aubriet, Frédéric; Carré, Vincent

    2010-02-05

    Laser-based aerosol mass spectrometry in both on-line and off-line modes has become an essential tool to analyze airborne and industrial dust particles. The versatility of laser desorption and/or ionization appears to be a powerful tool to obtain the global composition of environment particles. Laser mass spectrometry to analyze inorganic (elemental and molecular), organic and biological aerosol components without or with a restricted number of preparation steps in both on-line and off-line modes can be regarded as an ideal analytical machine. However, some limitations are associated to this range of mass spectrometry techniques. This review presents the fundamental aspects of laser-based mass spectrometry and the different kinds of analyses, which may be done. A selected number of applications are then given which allows the reader to consider both the capabilities and the drawbacks of laser mass spectrometry to analyze dust environmental particles. Critical discussion is focused on comparison and new trends of these aerosol analytical techniques.

  4. Analysis of In-Situ of Ozone Measurements in Saharan Mineral Dust during AEROSE Cruises

    NASA Astrophysics Data System (ADS)

    Roper, E. D.; Morris, V. R.; Nalli, N. R.; Joseph, E.

    2012-12-01

    The trans-Atlantic Aerosol and Oceanographic Science Expeditions (AEROSE) are a series of experiments that began in 2004 and take place in the tropical Atlantic Ocean. AEROSE collects a unique set of critical measurements to characterize the microphysical and chemical evolution of the Saharan dust aerosols during long-range transport. Continuous in-situ surface level measurements over the tropical Atlantic allows for accurate determination of lower tropospheric ozone concentrations, and its effects on the regional environment and climate that may be used to validate satellite observations. Ozone is instrumental in regulating the atmosphere's oxidizing capacity and can influence background levels of trace chemical species which affect the composition of the atmosphere and create climatic variations. Several studies have shown that ozone concentrations diminish with increased loading of dust particles from the Sahara. Current theories indicate that decomposition of ozone may be due to NOx titrations, decreased radiation, photocatalysis, interactions with organics, or heterogeneous reactions. In effort to understand the response of marine boundary layer ozone with coarse aerosols, analyses of ozone concentrations and aerosol correlations found in dusty Saharan air masses from various cruises will be presented.

  5. Supplement analysis for continued operation of Lawrence Livermore National Laboratory and Sandia National Laboratories, Livermore. Volume 2: Comment response document

    SciTech Connect

    1999-03-01

    The US Department of Energy (DOE), prepared a draft Supplement Analysis (SA) for Continued Operation of Lawrence Livermore National Laboratory (LLNL) and Sandia National Laboratories, Livermore (SNL-L), in accordance with DOE`s requirements for implementation of the National Environmental Policy Act of 1969 (NEPA) (10 Code of Federal Regulations [CFR] Part 1021.314). It considers whether the Final Environmental Impact Statement and Environmental Impact Report for Continued Operation of Lawrence Livermore National Laboratory and Sandia National Laboratories, Livermore (1992 EIS/EIR) should be supplement3ed, whether a new environmental impact statement (EIS) should be prepared, or no further NEPA documentation is required. The SA examines the current project and program plans and proposals for LLNL and SNL-L, operations to identify new or modified projects or operations or new information for the period from 1998 to 2002 that was not considered in the 1992 EIS/EIR. When such changes, modifications, and information are identified, they are examined to determine whether they could be considered substantial or significant in reference to the 1992 proposed action and the 1993 Record of Decision (ROD). DOE released the draft SA to the public to obtain stakeholder comments and to consider those comments in the preparation of the final SA. DOE distributed copies of the draft SA to those who were known to have an interest in LLNL or SNL-L activities in addition to those who requested a copy. In response to comments received, DOE prepared this Comment Response Document.

  6. Dust devil dynamics

    NASA Astrophysics Data System (ADS)

    Horton, W.; Miura, H.; Onishchenko, O.; Couedel, L.; Arnas, C.; Escarguel, A.; Benkadda, S.; Fedun, V.

    2016-06-01

    A self-consistent hydrodynamic model for the solar heating-driven onset of a dust devil vortex is derived and analyzed. The toroidal flows and vertical velocity fields are driven by an instability that arises from the inversion of the mass density stratification produced by solar heating of the sandy surface soil. The nonlinear dynamics in the primary temperature gradient-driven vertical airflows drives a secondary toroidal vortex flow through a parametric interaction in the nonlinear structures. While an external tangential shear flow may initiate energy transfer to the toroidal vortex flow, the nonlinear interactions dominate the transfer of vertical-radial flows into a fast toroidal flow. This secondary flow has a vertical vorticity, while the primary thermal gradient-driven flow produces the toroidal vorticity. Simulations for the complex nonlinear structure are carried out with the passive convection of sand as test particles. Triboelectric charging modeling of the dust is used to estimate the charging of the sand particles. Parameters for a Dust Devil laboratory experiment are proposed considering various working gases and dust particle parameters. The nonlinear dynamics of the toroidal flow driven by the temperature gradient is of generic interest for both neutral gases and plasmas.

  7. Dust Devil Dynamics

    NASA Astrophysics Data System (ADS)

    Correa, C. E.; Escarguel, A.; Horton, W.; Arnas, C.; Couedel, L.; Benkadda, S.

    2013-12-01

    A self-consistent hydrodynamic model for the onset of a dust devil vortex is derived and analyzed. The horizontal toroidal flow and vertical velocity field are driven by the vertical temperature gradient instability of gravity waves. The critical temperature gradient is derived and the associated eigenmodes for simple models are given. The nonlinear dynamics in the vertical/horizontal flows drive the toroidal flow through a parametric decay process. Methods developed for triboelectric charging of dust are used to compute the electric polarization vector from the charging of the sand particles. Elementary comparisons are made with the data from dust devil observations and research and simulations by Farrell et al. 2004, 2006. The parameters for a proposed Dust Devil laboratory experiment at Aix-Marseille University are presented. Following R. L. Miller et al. JGR 2006 estimates are made of the overall contribution to the mid-latitude aerosol layer in the atmosphere that acts to moderate global climate temperature increases through a negative feedback loop. The problem has an analog in terms of the heating of the boron or beryllium coated steel vacuum vessel walls in tokamaks where the core plasma plays the role of the sun and has a temperature (~ 10keV ) that exceeds that of the core of the sun.

  8. The Lunar Surface: A Dusty Plasma Laboratory

    NASA Astrophysics Data System (ADS)

    Horanyi, M.; Brain, D.; Kempf, S.; Munsat, T.; Robertson, S. H.; Sternovsky, Z.

    2011-12-01

    The lunar surface is an excellent laboratory to study dusty plasma processes that are relevant to all airless planetary objects. The solar wind and UV radiation lead to charging of exposed surfaces, and the formation of plasma sheaths above them. Near-surface intense electric fields are thought to be capable of mobilizing and transporting small charged dust particles. Remote sensing and in situ observations indicating dust transport on the Moon date back to the Apollo era and remain highly controversial. There are many unresolved issues about the physical processes that have to this point prevented the development of a coherent explanation for the existing observations. Dust transport on airless bodies can significantly alter our interpretation of spectral identification of asteroids, the small-scale surface features of Mercury, and the Martian moons Phobos and Deimos. Understanding the behavior of dust laden plasma sheaths is of interest in basic plasma and planetary sciences, and holds the key to efficient dust hazard mitigation for the long-term use of optical and mechanical equipment used for robotic and/or human exploration. NASA Lunar Science Institute's Colorado Center of Lunar Dust is focused on experimental and theoretical investigations of dusty plasmas, and the effects of hypervelocity dust impacts on surfaces. This presentation will describe a series of small-scale laboratory experiments investigating the properties of photoelectron sheaths, and the emergence of intense electric fields near boundaries of lit and dark surfaces and regions shielded and exposed to the solar wind plasma flow. Our progress in the analysis and interpretation of the laboratory observations using simple analytic models and complex plasma simulation tools indicates that these models can be used to predict the expected properties of the lunar near-surface environment with increasing confidence. Based on our laboratory and theoretical efforts, we will also report on the status of

  9. Stability analysis of non-thermal complex astrofluids in the presence of polarized dust-charge fluctuations

    NASA Astrophysics Data System (ADS)

    Dutta, P.; Das, P.; Karmakar, P. K.

    2016-10-01

    The panoptic influence of plasma q-nonextensivity and dust-charge fluctuations on the gravito-electro-magnetic stability behaviour of a realistic non-thermal complex astroplasma model configuration with infinite geometrical extension is reconnoitered. It includes active viscoelasticity and dust polarization force-field effects in quasi-neutral hydrostatic equilibrium on the astrophysical fluid scales of space and time. The nontrivial linear model is simplified with the Jeans homogenization assumption (Jeans swindle, no zeroth-order force-field). It analytically and logically enables us to relax from the inclusion of large-scale inhomogeneities and of associated intrinsic complications. The role of boundary effects on the dynamical stability is assumed to be insignificant. We apply a standard technique of the Fourier formulaic plane-wave analysis over the basic cloud-structuring equations in a closed integrated form. It reduces the model Fourier algebraic equations decoupling into a unique form of cubic dispersion relation having mixed variable coefficients, which, indeed, explicitly, evolve on the diverse model plasma parameters. It is interestingly seen that the polarization and nonextensive effects directly play destabilizing roles. In contrast, the viscoelasticity and magnetic field create stabilizing effects on the instability. The pragmatic significance and applicability in the context of astro-cosmo-galactic environments are briefly indicated aboard analytic facts and introspective faults.

  10. THE ESTABLISHMENT OF LABORATORY GUIDELINES FOR ANALYSIS OF BIOTERRORISM SAMPLES

    EPA Science Inventory

    After the attack on the World Trade Center on September 11, 2002, and the subsequent deaths associated with Bacillus anthracis spore contaminated mail, a worldwide need was apparent for increased laboratory capacity to safely analyze bioterrorism samples. The U.S. Department of ...

  11. A Simultaneous Analysis Problem for Advanced General Chemistry Laboratories.

    ERIC Educational Resources Information Center

    Leary, J. J.; Gallaher, T. N.

    1983-01-01

    Oxidation of magnesium metal in air has been used as an introductory experiment for determining the formula of a compound. The experiment described employs essentially the same laboratory procedure but is significantly more advanced in terms of information sought. Procedures and sample calculations/results are provided. (JN)

  12. Amchitka Island Environmental Analysis at Idaho National Laboratory

    SciTech Connect

    Gracy Elias; W. F. Bauer; J.G. Eisenmenger; C.C. Jensen; B.K. Schuetz; T. C. Sorensen; B.M. White; A. L. Freeman; M. E. McIlwain

    2005-08-01

    The Idaho National Laboratory (INL) provided support to Consortium for Risk Evaluation with Stakeholder Participation (CRESP) in their activities which is supported by the Department of Energy (DOE) to assess the impact of past nuclear testing at Amchitka Island on the ecosystemof the island and surrounding ocean. INL participated in this project in three phases, Phase 1, Phase 2 and Phase 3.

  13. A comprehensive parameterization of heterogeneous ice nucleation of dust surrogate: laboratory study with hematite particles and its application to atmospheric models

    NASA Astrophysics Data System (ADS)

    Hiranuma, N.; Paukert, M.; Steinke, I.; Zhang, K.; Kulkarni, G.; Hoose, C.; Schnaiter, M.; Saathoff, H.; Möhler, O.

    2014-12-01

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

  14. Integrated medical and behavioral laboratory measurement system engineering analysis and laboratory specification

    NASA Technical Reports Server (NTRS)

    Grave, C.; Margold, D. W.

    1973-01-01

    Site selection, program planning, cost and design studies for support of the IMBLMS program were investigated. Accomplishments are reported for the following areas: analysis of responses to site selection criteria, space-oriented biotechnology, life sciences payload definition, and program information transfer.

  15. Numerical Prediction of Dust. Chapter 10

    NASA Technical Reports Server (NTRS)

    Benedetti, Angela; Baldasano, J. M.; Basart, S.; Benincasa, F.; Boucher, O.; Brooks, M.; Chen, J. P.; Colarco, P. R.; Gong, S.; Huneeus, N.; Jones, L; Lu, S.; Menut, L.; Mulcahy, J.; Nickovic, S.; Morcrette, J.-J.; Perez, C.; Reid, J. S.; Sekiyama, T. T.; Tanaka, T.; Terradellas, E.; Westphal, D. L.; Zhang, X.-Y.; Zhou, C.-H.

    2013-01-01

    Covers the whole breadth of mineral dust research, from a scientific perspective Presents interdisciplinary work including results from field campaigns, satellite observations, laboratory studies, computer modelling and theoretical studies Explores the role of dust as a player and recorder of environmental change This volume presents state-of-the-art research about mineral dust, including results from field campaigns, satellite observations, laboratory studies, computer modelling and theoretical studies. Dust research is a new, dynamic and fast-growing area of science and due to its multiple roles in the Earth system, dust has become a fascinating topic for many scientific disciplines. Aspects of dust research covered in this book reach from timescales of minutes (as with dust devils, cloud processes, and radiation) to millennia (as with loess formation and oceanic sediments), making dust both a player and recorder of environmental change. The book is structured in four main parts that explore characteristics of dust, the global dust cycle, impacts of dust on the Earth system, and dust as a climate indicator. The chapters in these parts provide a comprehensive, detailed overview of this highly interdisciplinary subject. The contributions presented here cover dust from source to sink and describe all the processes dust particles undergo while travelling through the atmosphere. Chapters explore how dust is lifted and transported, how it affects radiation, clouds, regional circulations, precipitation and chemical processes in the atmosphere, and how it deteriorates air quality. The book explores how dust is removed from the atmosphere by gravitational settling, turbulence or precipitation, how iron contained in dust fertilizes terrestrial and marine ecosystems, and about the role that dust plays in human health. We learn how dust is observed, simulated using computer models and forecast. The book also details the role of dust deposits for climate reconstructions

  16. Dust Cloud Dynamics in Complex Plasma Afterglow

    SciTech Connect

    Layden, B.; Samarian, A. A.; Vladimirov, S. V.; Coueedel, L.

    2008-09-07

    Experimental observations of dust cloud dynamics in a RF discharge afterglow are presented. Image analysis is used to extract information from videos taken of the plasma. Estimations of the mean confining electric field have been made for different experimental conditions using a model for the contraction of the dust cloud. Dust particle trajectories in the late afterglow evidence the co-existence of positively and negatively charged dust particles.

  17. [Drinking water analysis for Legionella. Suggestions for sampling, laboratory analysis and assessment].

    PubMed

    Schaefer, B

    2007-03-01

    Drinking water analysis for Legionella from building installations is done quite frequently. Some questions arise from experience with this analysis. They will be discussed to allow uniform and comparable execution. Application of DIN EN ISO 19458 will lead to changes in the sampling procedure. This may make changes necessary even in current sampling and assessment programs. Concerning laboratory investigation, quality control of membrane filters and media turned out to be crucial. The assessment of quantitative results requires knowledge of the drinking water distribution system and of other facts that may be relevant for hygiene. Therefore, the assessment ought to be conducted by somebody with the respective knowledge.

  18. Space dust and debris; Proceedings of the Topical Meeting of the Interdisciplinary Scientific Commission B (Meetings B2, B3, and B5) of the COSPAR 28th Plenary Meeting, The Hague, Netherlands, June 25-July 6, 1990

    NASA Technical Reports Server (NTRS)

    Kessler, D. J. (Editor); Zarnecki, J. C. (Editor); Matson, D. L. (Editor)

    1991-01-01

    The present conference on space dust and debris encompasses orbital debris, in situ measurements and laboratory analysis of space-dust particles, comparative studies of comets, asteroids, and dust, the protection and maneuvering of spacecraft in space-debris environments, and the out-of-elliptic distribution of interplanetary dust derived from near-earth flux. Specific issues addressed include asteroid taxonomy, the optical properties of dust from cometary and interplanetary grains, light scattering by rough surfaces on asteroidal/lunar regoliths, and the first results of particulate impacts and foil perforations on the Long Duration Exposure Facility. Also addressed are collision probability and spacecraft disposition in the geostationary orbit, a flash on the moon caused by orbital debris, the limits of population growth in low earth orbit due to collisional cascading, and the simulation of cosmic man-made dust effects on space-vehicle elements in rocket and laboratory experiments.

  19. Risk assessment and optimization (ALARA) analysis for the environmental remediation of Brookhaven National Laboratory`s hazardous waste management facility

    SciTech Connect

    Dionne, B.J.; Morris, S.C. III; Baum, J.W.

    1998-01-01

    The Department of Energy`s (DOE) Office of Environment, Safety, and Health (EH) sought examples of risk-based approaches to environmental restoration to include in their guidance for DOE nuclear facilities. Extensive measurements of radiological contamination in soil and ground water have been made at Brookhaven National Laboratory`s Hazardous Waste Management Facility (HWMF) as part of a Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) remediation process. This provided an ideal opportunity for a case study. This report provides a risk assessment and an {open_quotes}As Low as Reasonably Achievable{close_quotes} (ALARA) analysis for use at other DOE nuclear facilities as an example of a risk-based decision technique. This document contains the Appendices for the report.

  20. Risk assessment and optimization (ALARA) analysis for the environmental remediation of Brookhaven National Laboratory`s hazardous waste management facility

    SciTech Connect

    Dionne, B.J.; Morris, S. III; Baum, J.W.

    1998-03-01

    The Department of Energy`s (DOE) Office of Environment, Safety, and Health (EH) sought examples of risk-based approaches to environmental restoration to include in their guidance for DOE nuclear facilities. Extensive measurements of radiological contamination in soil and ground water have been made at Brookhaven National Laboratory`s Hazardous Waste Management Facility (HWMF) as part of a Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) remediation process. This provided an ideal opportunity for a case study. This report provides a risk assessment and an {open_quotes}As Low as Reasonably Achievable{close_quotes} (ALARA) analysis for use at other DOE nuclear facilities as an example of a risk-based decision technique.

  1. Detached Dust Layers in Regional and Global Dust Events on Mars

    NASA Astrophysics Data System (ADS)

    Heavens, Nicholas

    2014-11-01

    Throughout much of the year in Mars's tropics, the vertical distribution of dust has a local maximum in mass mixing ratio significantly above the inferred height of the planetary boundary layer: a feature known as a "detached dust layer." Detached dust layering also has been observed in the extratropics. Modeling shows that dust-heated convective plumes within dust storms can rapidly transport dust vertically to altitudes of 40 km or more. These "rocket dust storm" plumes minimally mix with the surrounding environment, resulting in detached dust layers. Visible image climatology of dust storm activity argue against the "rocket dust storm" mechanism being dominant in northern spring and summer, when detached dust layer formation is common but tropical dust storm activity is rare. Some detached dust layers undoubtedly form by the "rocket dust storm" mechanism, such as those during regional and global dust events, which reach altitudes of 45-75 km above the MOLA datum and have mass mixing ratios of 40-260 ppm, equivalent to well-mixed visible column opacities of 3.6-23. These layers are not just a phenomenological curiosity. The plumes that generate them could play a role in dust storm development analogous to convection in tropical cyclone activity on Earth: "the dusty hurricane" analogy.Here I report on detached dust layers from one global dust event and five regional dust events observed by the Mars Climate Sounder on board Mars Reconnaissance Orbiter. I examine the history of detached dust layer activity during the dust events in the context of possible limb observations of deep convection as well as visible imaging of dust lifting activity.Global dust events are associated with detached dust layers that are thicker and/or reach higher altitudes than in regional dust events. However, detached dust layers in these dust events do not originate from the tropics alone or have a simple relationship with dust lifting activity, arguing against strong analogy with

  2. Numerical Modeling of 1997-2006 Asian Dust and Mass Budget Analysis in East Asia and West Pacific

    NASA Astrophysics Data System (ADS)

    Liu, M.; Westphal, D. L.

    2006-12-01

    East Asia has two of the Earth's major natural dust sources: the Taklamakan Desert in west China and the Gobi Desert in Mongolia and northwest China. Desertification has increased dust-erodible areas surrounding the deserts so the dust storm frequency has increased in the last few decades. Severe dust storms not only impact East Asia, but also can reach far beyond the continent, as did the dust clouds of April 1998, 2001 and 2005 that drifted over the Pacific Ocean and to North America. The US Navy's operational Coupled Ocean/Atmospheric Mesoscale Prediction System (COAMPS) is used to simulate the dust events for the springs of 1997 through 2006 at a resolution of one quarter of degree with multiple size bins. We use the modeled data to investigate the spatial and temporal dependence of dust emission, transport and deposition, and estimate the impacts of dust on environment. The distribution of dust plumes in area coverage and vertical depth is studied, as is the inter-annual variation of dust patterns from the different deserts of China and Mongolia, and the fluxes across the Pacific. It is found that PM10 is the dominant fraction particles over the continent and near the ocean, while PM2.5 becomes dominant in the boundary outflow along 170E. The details of analyzed model results will be presented at the meeting.

  3. Selecting baghouse dust collectors

    SciTech Connect

    Moore, S.; Rubak, J.; Jolin, M. |

    1997-04-01

    A thorough analysis of the dust to be captured and determination of specific application requirements are necessary when designing a baghouse collection system. Independent consultants specializing in pollution control equipment and manufacturers with experience in several types of collectors are possible sources of assistance. These experts typically have testing facilities to analyze the dust characteristics. This final article of a two-part series on baghouse design and selection concentrates on application considerations created by the type of dust handled, selecting the best filtration media, selecting the best filtration media, and determining the air-to-cloth (A/C) ratio. The first article discussed bag sizing and cleaning methods and housing and hopper designs.

  4. Experiments on Dust Grain Charging

    NASA Technical Reports Server (NTRS)

    Abbas, M. N.; Craven, P. D.; Spann, J. F.; Tankosic, D.; LeClair, A.; West, E. A.

    2004-01-01

    Dust particles in various astrophysical environments are charged by a variety of mechanisms generally involving collisional processes with other charged particles and photoelectric emission with UV radiation from nearby sources. The sign and the magnitude of the particle charge are determined by the competition between the charging processes by UV radiation and collisions with charged particles. Knowledge of the particle charges and equilibrium potentials is important for understanding of a number of physical processes. The charge of a dust grain is thus a fundamental parameter that influences the physics of dusty plasmas, processes in the interplanetary medium and interstellar medium, interstellar dust clouds, planetary rings, cometary and outer atmospheres of planets etc. In this paper we present some results of experiments on charging of dust grains carried out on a laboratory facility capable levitating micron size dust grains in an electrodynamic balance in simulated space environments. The charging/discharging experiments were carried out by exposing the dust grains to energetic electron beams and UV radiation. Photoelectric efficiencies and yields of micron size dust grains of SiO2, and lunar simulates obtained from NASA-JSC will be presented.

  5. [Analysis on chemical and physical properties of Beijing super dust storm in spring of 2004].

    PubMed

    He, Xin-Xing; Wang, Yue-Si; Wen, Tian-Xue; Hu, Bo

    2005-09-01

    On March 27, 2004 a super dust storm occurred in Beijing. The concentration of the aerosol and the element concentration of the aerosol were analyzed. The velocity of wind and radiation of ground were also measured. TSP increased 300 - 400 percent. PM2.5 increased 200 - 300 percent, but the concentration of the fine particle decreased. The elements like Na, Mg, Al, Mn and Fe mainly distribute in coarse particles. The contaminated elements such as Zn and Pb mainly distribute in fine particles. The contaminated elements mainly come from local source. The total radiation reduced 37.8 percent. With the increased of the velocity of the wind, the concentration of the coarse particle increased notability, the concentration of the fine particle decreased.

  6. Analysis of water ice and ice/dust mixtures using laser-induced breakdown spectroscopy (LIBS).

    SciTech Connect

    Cremers, D. A.; Brown, Kari; Gibson, L. E.; Ferris, M. J.; Wiens, R. C.; Maurice, S.

    2003-01-01

    In 1992, LIBS was proposed as a new method for stand-off detection of geological samples for use on landers and rovers to Mars. Recently, there has been increased interest in the technique for this and other space applications and studies have determined some of the characteristics and capabilities of the method under the conditions that these measurements will have to be made. In addition to rocks and soils, there is interest in using LIBS to analyze ices and dusts entrained in ice . This is especially true for missions to the Mars polar regions . Of particular interest is determining the nature of polar layered deposits, the geochemistry of polar surface materials, detection of water ice and the distribution of ice, and the presence of possible organics in these materials (via C/N ratios)

  7. Laboratory Ventilation and Safety.

    ERIC Educational Resources Information Center

    Steere, Norman V.

    1965-01-01

    In order to meet the needs of both safety and economy, laboratory ventilation systems must effectively remove air-borne toxic and flammable materials and at the same time exhaust a minimum volume of air. Laboratory hoods are the most commonly used means of removing gases, dusts, mists, vapors, and fumed from laboratory operations. To be effective,…

  8. Economic Analysis of Requests for Laboratory Tests in Primary Health Care Centers

    PubMed Central

    Zunic, Lejla

    2012-01-01

    Introduction: Operation of the Primary health care center and Medical-biochemical laboratories depends on the number of performed laboratory tests. The number of unnecessary tests significantly affect the operation of health institutions. Material and methods: We analyzed the 1000 requests for laboratory tests at the Primary Health Care Centre in Gracanica from primary care units. Based on the requests for laboratory diagnostics advisable diagnoses from primary health care unit in the Primary Health Care Center (PHC) we made an economic analysis of the total required laboratory tests in the requests for laboratory diagnosis. Incorporating the economic analysis of laboratory tests in requests for laboratory diagnosis by doctors in primary health care (PHC) and the economic analysis of laboratory tests by the disease in primary health care. Results: The economic value of 5333 laboratory tests was 84 312 points (1 point is 0.80 KM). Of the total value of the index score requirements of GPs are 44, 1%, the requirement of family doctors account for 40% and requirements of other specialists make up 15, 9%.. Discussion: In the requests of the PHC units for laboratory tests are required all levels of services: urine, CBC, SE, glucose, bilirubine, ALT, AST, AF, CK, cholesterol, HDL chol., triglicerdes, creatinine, urea, uric acid, CRP, fibrinogen, calcium and phosphorus. The following requests are the most common laboratory tests: urine, CBC, blood glucose, cholesterol, triglycerides, aminotransferases, creatinine, urea. The doctors in family practice most often requested: blood glucose, urine, CBC, SE, TGL. , Chol., ALT, AST, creatinine and urea. General practitioners were demanding more cholesterol and triglycerides, and family medicine doctors were demanding less cholesterol and triglycerides and more often CRP, fibrinogen, ALT, AST, what from the level of economic cost analysis rises the issue whether this was justified? PMID:23322950

  9. Planetary Magnetosphere Probed by Charged Dust Particles

    NASA Astrophysics Data System (ADS)

    Sternovsky, Z.; Horanyi, M.; Gruen, E.; Srama, R.; Auer, S.; Kempf, S.; Krueger, H.

    2010-12-01

    In-situ and remote sensing observations combined with theoretical and numerical modeling greatly advanced our understanding planetary magnetospheres. Dust is an integral component of the Saturnian and Jovian magnetospheres where it can act as a source/sink of plasma particles (dust particles are an effective source for plasma species like O2, OH, etc. through sputtering of ice particles, for example); its distribution is shaped by electrodynamic forces coupled radiation pressure, plasma, and neutral drag, for example. The complex interaction can lead to unusual dust dynamics, including the transport, capture, and ejection of dust grains. The study of the temporal and spatial evolution of fine dust within or outside the magnetosphere thus provides a unique way to combine data from a large number of observations: plasma, plasma wave, dust, and magnetic field measurements. The dust detectors on board the Galileo and Cassini spacecrafts lead to major discoveries, including the jovian dust stream originating from Io or the in-situ sampling and analysis of the plumes of Enceladus. Recent advancement in dust detector technology enables accurate measurement of the dust trajectory and elemental composition that can greatly enhance the understanding of dust magnetorspheric interaction and indentify the source of the dust with high precision. The capabilities of a modern dust detector thus can provide support for the upcoming Europa Jupiter System Mission.

  10. Crystallization and Preliminary X-ray Analysis of Der f 2, a Potent Allergen Derived from the House Dust Mite

    NASA Technical Reports Server (NTRS)

    Roeber, Dana; Achari, Aniruddha; Takai, Toshiro; Okumura, Yasushi; Scott, David L.; Curreri, Peter (Technical Monitor)

    2002-01-01

    Although a number of allergens have been identified and isolated, the underlying molecular basis for the potent immune response is poorly understood. House dust mites (Dermatophugoides sp.) are particularly ubiquitous contributors to atopy in developed countries. The rhinitis, dermatitis, and asthma associated with allergic reactions to these arthropods are often caused by relatively small (125-129 amino acids) mite proteins of unclear biological function. Der f 2, a major allergen from the mite Dermatophagoides farinae, has been recombinantly expressed and characterized. The Der f 2 protein has been crystallized in our laboratory and a native data set collected at a synchrotron source. The crystals belong to the orthorhombic space group I422 with unit cell parameters of a = 95.2 Angstroms, b = 95.2 Angstroms, and c = 103.3 Angstroms. An essentially complete (97.2%) data set has been collected to 2.4 Angstroms. Attempts to solve the crystal structure of Der f 2 by molecular replacement using the available NMR coordinates for either Der f 2 or Der p 2 (the homologous protein from D. pterovssinus) failed to reveal a creditable solution.

  11. Space Weathering Products Found on the Surfaces of the Itokawa Dust Particles: A Summary of the Initial Analysis

    NASA Technical Reports Server (NTRS)

    Noguchi, T.; Kimura, M.; Hashimoto, T.; Konno, M.; Nakamura, T.; Ogami, T.; Ishida, H.; Sagae, R.; Tsujimoto, S.; Tsuchiyama, A,; Zolensky, M. E.; Tanaka, M.; Fujimura, A.; Abe, M.; Yada, T.; Mukai, T.; Ueno, M.; Okada, T.; Shirai, K.; Ishibashi, Y.; Okazaki, R.

    2012-01-01

    Surfaces of airless bodies exposed to interplanetary space gradually have their structures, optical properties, chemical compositions, and mineralogy changed by solar wind implantation and sputtering, irradiation by galactic and solar cosmic rays, and micrometeorite bombardment. These alteration processes and the resultant optical changes are known as space weathering [1, 2, 3]. Our knowledge of space weathering has depended almost entirely on studies of the surface materials returned from the Moon and regolith breccia meteorites [1, 4, 5, 6] until the surface material of the asteroid Itokawa was returned to the Earth by the Hayabusa spacecraft [7]. Lunar soil studies show that space weathering darkens the albedo of lunar soil and regolith, reddens the slopes of their reflectance spectra, and attenuates the characteristic absorption bands of their reflectance spectra [1, 2, 3]. These changes are caused by vapor deposition of small (<40 nm) metallic Fe nanoparticles within the grain rims of lunar soils and agglutinates [5, 6, 8]. The initial analysis of the Itokawa dust particles revealed that 5 out of 10 particles have nanoparticle-bearing rims, whose structure varies depending on mineral species. Sulfur-bearing Fe-rich nanoparticles (npFe) exist in a thin (5-15 nm) surface layer (zone I) on olivine, low-Ca pyroxene, and plagioclase, suggestive of vapor deposition. Sulfur-free npFe exist deeper inside (<60 nm) ferromagnesian silicates (zone II). Their texture suggests formation by amorphization and in-situ reduction of Fe2+ in ferromagnesian silicates [7]. On the other hand, nanophase metallic iron (npFe0) in the lunar samples is embedded in amorphous silicate [5, 6, 8]. These textural differences indicate that the major formation mechanisms of the npFe0 are different between the Itokawa and the lunar samples. Here we report a summary of the initial analysis of space weathering of the Itokawa dust particles.

  12. CTEPP STANDARD OPERATING PROCEDURE FOR EXTRACTING AND PREPARING DUST AND SOIL SAMPLES FOR ANALYSIS OF POLAR PERSISTENT ORGANIC POLLUTANTS (SOP-5.15)

    EPA Science Inventory

    The method for extracting and preparing a dust or soil sample for analysis of polar persistent organic pollutants is summarized in this SOP. It covers the extraction, concentration, and derivatization of samples that are to be analyzed by gas chromatography/mass spectrometry.

  13. Dust Devil Tracks

    NASA Astrophysics Data System (ADS)

    Reiss, Dennis; Fenton, Lori; Neakrase, Lynn; Zimmerman, Michael; Statella, Thiago; Whelley, Patrick; Rossi, Angelo Pio; Balme, Matthew

    2016-11-01

    -sized material that is eroded from the outer vortex area of a dust devil is redeposited in annular patterns in the central vortex region. This type of DDT can also be found in on Mars in orbital image data, and although in situ studies are lacking, terrestrial analog studies, laboratory work, and numerical modeling suggest they have the same formation mechanism as those on Earth. Finally, bright DDTs are characterized by their continuous track pattern and high albedo compared to their undisturbed surroundings. They are found on both planets, but to date they have only been analyzed in situ on Earth. Here, the destruction of aggregates of dust, silt and sand by dust devils leads to smooth surfaces in contrast to the undisturbed rough surfaces surrounding the track. The resulting change in photometric properties occurs because the smoother surfaces have a higher reflectance compared to the surrounding rough surface, leading to bright DDTs. On Mars, the destruction of surficial dust-aggregates may also lead to bright DDTs. However, higher reflective surfaces may be produced by other formation mechanisms, such as dust compaction by passing dust devils, as this may also cause changes in photometric properties. On Mars, DDTs in general are found at all elevations and on a global scale, except on the permanent polar caps. DDT maximum areal densities occur during spring and summer in both hemispheres produced by an increase in dust devil activity caused by maximum insolation. Regionally, dust devil densities vary spatially likely controlled by changes in dust cover thicknesses and substrate materials. This variability makes it difficult to infer dust devil activity from DDT frequencies. Furthermore, only a fraction of dust devils leave tracks. However, DDTs can be used as proxies for dust devil lifetimes and wind directions and speeds, and they can also be used to predict lander or rover solar panel clearing events. Overall, the high DDT frequency in many areas on Mars leads to drastic

  14. An Analysis of Medical Laboratory Technology Journals' Instructions for Authors.

    PubMed

    Horvat, Martina; Mlinaric, Ana; Omazic, Jelena; Supak-Smolcic, Vesna

    2016-08-01

    Instructions for authors (IFA) need to be informative and regularly updated. We hypothesized that journals with a higher impact factor (IF) have more comprehensive IFA. The aim of the study was to examine whether IFA of journals indexed in the Journal Citation Reports 2013, "Medical Laboratory Technology" category, are written in accordance with the latest recommendations and whether the quality of instructions correlates with the journals' IF. 6 out of 31 journals indexed in "Medical Laboratory Technology" category were excluded (unsuitable or unavailable instructions). The remaining 25 journals were scored based on a set of 41 yes/no questions (score 1/0) and divided into four groups (editorial policy, research ethics, research integrity, manuscript preparation) by three authors independently (max score = 41). We tested the correlation between IF and total score and the difference between scores in separate question groups. The median total score was 26 (21-30) [portion of positive answers 0.63 (0.51-0.73)]. There was no statistically significant correlation between a journal's IF and the total score (rho = 0.291, P = 0.159). IFA included recommendations concerning research ethics and manuscript preparation more extensively than recommendations concerning editorial policy and research integrity (Ht = 15.91, P = 0.003). Some policies were poorly described (portion of positive answers), for example: procedure for author's appeal (0.04), editorial submissions (0.08), appointed body for research integrity issues (0.08). The IF of the "Medical Laboratory Technology" journals does not reflect a journals' compliance to uniform standards. There is a need for improving editorial policies and the policies on research integrity.

  15. Los Alamos National Laboratory Economic Analysis Capability Overview

    SciTech Connect

    Boero, Riccardo; Edwards, Brian Keith; Pasqualini, Donatella; Rivera, Michael Kelly

    2016-04-19

    Los Alamos National Laboratory has developed two types of models to compute the economic impact of infrastructure disruptions. FastEcon is a fast running model that estimates first-­order economic impacts of large scale events such as hurricanes and floods and can be used to identify the amount of economic activity that occurs in a specific area. LANL’s Computable General Equilibrium (CGE) model estimates more comprehensive static and dynamic economic impacts of a broader array of events and captures the interactions between sectors and industries when estimating economic impacts.

  16. Fingerprints in the Dust

    NASA Technical Reports Server (NTRS)

    2001-01-01

    These MISR nadir-camera images of eastern China compare a somewhat hazy summer view from July 9, 2000 (left) with a spectacularly dusty spring view from April 7, 2001 (middle). The left-hand and middle images are from Terra orbits 2967 and 6928, respectively, and extend from central Manchuria near the top to portions of North and South Korea at the bottom. They are approximately 380 kilometers in width.

    Asia's desert areas are prone to soil erosion, as underground water tables are lowered by prolonged drought and by industrial and agricultural water use. Heavy winds blowing eastward across the arid and sparsely vegetated surfaces of Mongolia and western China pick up large quantities of yellow dust. Airborne dust clouds from the April 2001 storm blew across the Pacific Ocean and were carried as far as North America. The minerals transported in this manner are believed to provide nutrients for both oceanic and land ecosystems.

    According to the Xinhua News Agency in China, nearly one million tons of Gobi Desert dust blow into Beijing each year. During a similar dust outbreak last year, the Associated Press reported that the visibility in Beijing had been reduced the point where buildings were barely visible across city streets, and airline schedules were significantly disrupted. The dust has also been implicated in adverse health effects such as respiratory discomfort and eye irritation.

    The image on the right is a higher resolution MISR nadir-camera view of a portion of the April 7, 2001 dust cloud. It covers an area roughly 250 kilometers wide by 470 kilometers high. When viewed at full magnification, a number of atmospheric wave features, like the ridges and valleys of a fingerprint, are apparent. These are probably induced by surface topography, which can disturb the wind flow. A few small cumulus clouds are also visible, and are casting shadows on the thick lower dust layer.

    Analyses of images such as these constitute one phase of MISR

  17. 7 CFR 91.37 - Standard hourly fee rate for laboratory testing, analysis, and other services.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Standard hourly fee rate for laboratory testing, analysis, and other services. 91.37 Section 91.37 Agriculture Regulations of the Department of Agriculture... AGRICULTURE (CONTINUED) COMMODITY LABORATORY TESTING PROGRAMS SERVICES AND GENERAL INFORMATION Fees...

  18. 7 CFR 91.37 - Standard hourly fee rate for laboratory testing, analysis, and other services.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Standard hourly fee rate for laboratory testing, analysis, and other services. 91.37 Section 91.37 Agriculture Regulations of the Department of Agriculture... AGRICULTURE (CONTINUED) COMMODITY LABORATORY TESTING PROGRAMS SERVICES AND GENERAL INFORMATION Fees...

  19. The Alcohol Dehydrogenase Kinetics Laboratory: Enhanced Data Analysis and Student-Designed Mini-Projects

    ERIC Educational Resources Information Center

    Silverstein, Todd P.

    2016-01-01

    A highly instructive, wide-ranging laboratory project in which students study the effects of various parameters on the enzymatic activity of alcohol dehydrogenase has been adapted for the upper-division biochemistry and physical biochemistry laboratory. Our two main goals were to provide enhanced data analysis, featuring nonlinear regression, and…

  20. Development, Implementation, and Analysis of a National Survey of Faculty Goals for Undergraduate Chemistry Laboratory

    ERIC Educational Resources Information Center

    Bruck, Aaron D.; Towns, Marcy

    2013-01-01

    This work reports the development of a survey for laboratory goals in undergraduate chemistry, the analysis of reliable and valid data collected from a national survey of college chemistry faculty, and a synthesis of the findings. The study used a sequential exploratory mixed-methods design. Faculty goals for laboratory emerged across seven…

  1. Application of wind-profiling radar data to the analysis of dust weather in the Taklimakan Desert.

    PubMed

    Wang, Minzhong; Wei, Wenshou; Ruan, Zheng; He, Qing; Ge, Runsheng

    2013-06-01

    The Urumqi Institute of Desert Meteorology of the China Meteorological Administration carried out an atmospheric scientific experiment to detect dust weather using a wind-profiling radar in the hinterland of the Taklimakan Desert in April 2010. Based on the wind-profiling data obtained from this experiment, this paper seeks to (a) analyze the characteristics of the horizontal wind field and vertical velocity of a breaking dust weather in a desert hinterland; (b) calculate and give the radar echo intensity and vertical distribution of a dust storm, blowing sand, and floating dust weather; and (c) discuss the atmosphere dust counts/concentration derived from the wind-profiling radar data. Studies show that: (a) A wind-profiling radar is an upper-air atmospheric remote sensing system that effectively detects and monitors dust. It captures the beginning and ending of a dust weather process as well as monitors the sand and dust being transported in the air in terms of height, thickness, and vertical intensity. (b) The echo intensity of a blowing sand and dust storm weather episode in Taklimakan is about -1~10 dBZ while that of floating dust -1~-15 dBZ, indicating that the dust echo intensity is significantly weaker than that of precipitation but stronger than that of clear air. (c) The vertical shear of horizontal wind and the maintenance of low-level east wind are usually dynamic factors causing a dust weather process in Taklimakan. The moment that the low-level horizontal wind field finds a shear over time, it often coincides with the onset of a sand blowing and dust storm weather process. (d) When a blowing sand or dust storm weather event occurs, the atmospheric vertical velocity tends to be of upward motion. This vertical upward movement of the atmosphere supported with a fast horizontal wind and a dry underlying surface carries dust particles from the ground up to the air to form blown sand or a dust storm.

  2. Differences in implementation of gait analysis recommendations based on affiliation with a gait laboratory.

    PubMed

    Wren, Tishya A L; Elihu, Koorosh J; Mansour, Shaun; Rethlefsen, Susan A; Ryan, Deirdre D; Smith, Michelle L; Kay, Robert M

    2013-02-01

    This study examined the extent to which gait analysis recommendations are followed by orthopedic surgeons with varying degrees of affiliation with the gait laboratory. Surgical data were retrospectively examined for 95 patients with cerebral palsy who underwent lower extremity orthopedic surgery following gait analysis. Thirty-three patients were referred by two surgeons directly affiliated with the gait laboratory (direct affiliation), 44 were referred by five surgeons from the same institution but not directly affiliated with the gait laboratory (institutional affiliation), and 18 were referred by 10 surgeons from other institutions (no affiliation). Data on specific surgeries were collected from the gait analysis referral, gait analysis report, and operative notes. Adherence to the gait analysis recommendations was calculated by dividing the number of procedures where the surgery followed the gait analysis recommendation (numerator) by the total number of procedures initially planned, recommended by gait analysis, or done (denominator). Adherence with the gait analysis recommendations was 97%, 94%, and 77% for the direct, institutional, and no affiliation groups, respectively. Procedures recommended for additions to the surgical plan were added 98%, 87%, and 77% of the time. Procedures recommended for elimination were dropped 100%, 89%, and 88% of the time. Of 81 patients who had specific surgical plans prior to gait analysis, changes were implemented in 84% (68/81) following gait analysis recommendations. Gait analysis influences the treatment decisions of surgeons regardless of affiliation with the gait laboratory, although the influence is stronger for surgeons who practice within the same institution as the gait laboratory.

  3. Inter-laboratory study to improve the quality of the analysis of nutrients in rainwater chemistry

    NASA Astrophysics Data System (ADS)

    Karthikeyan, Sathrugnan; Balasubramanian, Rajasekhar; He, Jun

    This paper describes the results of an inter-laboratory study conducted for the analysis of nutrients (nitrate, ammonium, phosphate, total nitrogen (TN), and total phosphorus (TP)) in natural rainwater. For this purpose, rainwater samples were collected and aggregated in Singapore and homogenized. These samples were immediately filtered through 0.45 μm membrane filters and autoclaved for 15 min at 80 °C in order to stabilize the nutrients. The homogeneity and the stability of nutrients were rigorously tested for a period of three months initially. Upon ensuring the homogeneity and stability, the samples were distributed to 15 different laboratories from various countries around the world (Australia, Brazil, India, Mauritius, Singapore, Slovenia, Spain, Taiwan, and USA). Almost all laboratories have reported the analytical results for nitrate whereas only 8 of the 15 laboratories reported results for other nutrients such as ammonium, phosphate, TN, and TP. The discrepancy was mainly due to the presence of these nutrients in low concentration levels (particularly ammonium ion and phosphate). Not all the laboratories were equipped with analytical capabilities to conduct the analysis of nutrients in low concentration levels. Further, the uncertainty associated with the analysis of TN and TP restricted the number of laboratories that could report their analytical data on nutrients. All 14 laboratories reported nitrate-nitrogen results which were in good agreement with each other (0.68 ± 0.07 mg l -1). Similarly, the results of TN and TP were also comparable among at least 8 laboratories. This inter-laboratory study on the analysis of nutrients in natural rainwater, conducted for the first time, provided an opportunity to the participating laboratories to assess and improve their laboratory performance, thereby, improving the quality of their analytical data.

  4. An Automated Method of MFRSR Calibration for Aerosol Optical Depth Analysis with Application to an Asian Dust Outbreak over the United States.

    NASA Astrophysics Data System (ADS)

    Augustine, John A.; Cornwall, Christopher R.; Hodges, Gary B.; Long, Charles N.; Medina, Carlos I.; Deluisi, John J.

    2003-02-01

    northeast of Table Mountain, and to sun-photometer-derived aerosol optical depths at the National Renewable Energy Laboratory in Golden, Colorado, 50 km to the south. Both the Table Mountain and Golden stations are situated within a few kilometers of the Front Range of the Rocky Mountains, whereas the Pawnee station is on the eastern plains of Colorado. Time series of aerosol optical depth from Pawnee and Table Mountain stations compare well for 13 April when, according to the Naval Aerosol Analysis and Prediction System, an upper-level Asian dust plume enveloped most of Colorado. Aerosol optical depths at the Golden station for that event are generally greater than those at Table Mountain and Pawnee, possibly because of the proximity of Golden to Denver's urban aerosol plume. The dust over Colorado was primarily surface based on 17 April. On that day, aerosol optical depths at Table Mountain and Golden are similar but are 2 times the magnitude of those at Pawnee. This difference is attributed to meteorological conditions that favored air stagnation in the planetary boundary layer along the Front Range, and a west-to-east gradient in aerosol concentration. The magnitude and timing of the aerosol optical depth measurements at Table Mountain for these events are found to be consistent with independent measurements made at NASA Aerosol Robotic Network (AERONET) stations at Missoula, Montana, and at Bondville, Illinois.

  5. Equilibrium analysis for heavy metal cation removal using cement kiln dust.

    PubMed

    El Zayat, Mohamed; Elagroudy, Sherien; El Haggar, Salah

    2014-01-01

    Ion exchange, reverse osmosis, and chemical precipitation have been investigated extensively for heavy metal uptake. However, they are deemed too expensive to meet stringent effluent characteristics. In this study, cement kiln dust (CKD) was examined for the removal of target heavy metals. Adsorption studies in completely mixed batch reactors were used to generate equilibrium pH adsorption edges. Studies showed the ability of CKD to remove the target heavy metals in a pH range below that of precipitation after an equilibrium reaction time of 24 h. A surface titration experiment indicated negative surface charge of the CKD at pH below 10, meaning that electrostatic attraction of the divalent metals can occur below the pH required for precipitation. However, surface complexation was also important due to the substantive metal removal. Accordingly, a surface complexation model approach that utilizes an electrostatic term in the double-layer description was used to estimate equilibrium constants for the protolysis interactions of the CKD surface as well as equilibria between background ions and the sorbent surface. It was concluded that the removal strength of adsorption is in the order: Pb > Cu > Cd. The experiments were also supported by Fourier transform infrared spectroscopy (FTIR).

  6. 7 CFR 57.960 - Small importations for consignee's personal use, display, or laboratory analysis.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946...'s personal use, display, or laboratory analysis, and not for sale or distribution; which is...

  7. Inter-laboratory comparison of the in vivo comet assay including three image analysis systems.

    PubMed

    Plappert-Helbig, Ulla; Guérard, Melanie

    2015-12-01

    To compare the extent of potential inter-laboratory variability and the influence of different comet image analysis systems, in vivo comet experiments were conducted using the genotoxicants ethyl methanesulfonate and methyl methanesulfonate. Tissue samples from the same animals were processed and analyzed-including independent slide evaluation by image analysis-in two laboratories with extensive experience in performing the comet assay. The analysis revealed low inter-laboratory experimental variability. Neither the use of different image analysis systems, nor the staining procedure of DNA (propidium iodide vs. SYBR® Gold), considerably impacted the results or sensitivity of the assay. In addition, relatively high stability of the staining intensity of propidium iodide-stained slides was found in slides that were refrigerated for over 3 months. In conclusion, following a thoroughly defined protocol and standardized routine procedures ensures that the comet assay is robust and generates comparable results between different laboratories.

  8. Micromachined Dust Traps

    NASA Technical Reports Server (NTRS)

    Bearman, Gregory H.; Bradley, James G.

    1993-01-01

    Micromachined traps devised to capture dust particles for analysis without contaminating them. Based on micromachined structures retaining particles, rather than adhesives or greases interfering with scanning-electron-microscope analysis or x-ray imaging. Unlike maze traps and traps enmeshing particles in steel wool or similar materials, micromachined traps do not obscure trapped particles. Internal geometries of traps range from simple cones to U-shapes, all formed by etching silicon.

  9. Dynamic feature analysis for Voyager at the Image Processing Laboratory

    NASA Technical Reports Server (NTRS)

    Yagi, G. M.; Lorre, J. J.; Jepsen, P. L.

    1978-01-01

    Voyager 1 and 2 were launched from Cape Kennedy to Jupiter, Saturn, and beyond on September 5, 1977 and August 20, 1977. The role of the Image Processing Laboratory is to provide the Voyager Imaging Team with the necessary support to identify atmospheric features (tiepoints) for Jupiter and Saturn data, and to analyze and display them in a suitable form. This support includes the software needed to acquire and store tiepoints, the hardware needed to interactively display images and tiepoints, and the general image processing environment necessary for decalibration and enhancement of the input images. The objective is an understanding of global circulation in the atmospheres of Jupiter and Saturn. Attention is given to the Voyager imaging subsystem, the Voyager imaging science objectives, hardware, software, display monitors, a dynamic feature study, decalibration, navigation, and data base.

  10. Summary of failure analysis activities at Brookhaven National Laboratory

    SciTech Connect

    Cowgill, M.G.; Czajkowski, C.J.; Franz, E.M.

    1996-10-01

    Brookhaven National Laboratory has for many years conducted examinations related to the failures of nuclear materials and components. These examinations included the confirmation of root cause analyses, the determination of the causes of failure, identification of the species that accelerate corrosion, and comparison of the results of nondestructive examinations with those obtained by destructive examination. The results of those examinations, which had previously appeared in various formats (formal and informal reports, journal articles, etc.), have been collected together and summarized in the present report. The report is divided into sections according to the general subject matter (for example, corrosion, fatigue, etc.). Each section presents summaries of the information contained in specific reports and publications, all of which are fully identified as to title, authors, report number or journal reference, date of publication, and FIN number under which the work was performed.

  11. Coulometric Analysis Experiment for the Undergraduate Chemistry Laboratory

    ERIC Educational Resources Information Center

    Dabke, Rajeev B.; Gebeyehu, Zewdu; Thor, Ryan

    2011-01-01

    An undergraduate experiment on coulometric analysis of four commercial household products is presented. A special type of coulometry cell made of polydimethylsiloxane (PDMS) polymer is utilized. The PDMS cell consists of multiple analyte compartments and an internal network of salt bridges. Experimental procedure for the analysis of the acid in a…

  12. Dust and Ocean Plants

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Adding iron to the diet of marine plant life has been shown in shipboard experiments to boost the amount of carbon-absorbing phytoplankton in certain parts of the world's oceans. A new study promises to give scientists their first global picture of the extent of these unique 'iron-limited' ocean regions, an important step in understanding how the ocean's biology controls the flow of carbon between the atmosphere and the ocean. The new study by researchers at NASA's Goddard Space Flight Center and the Department of Energy's Oak Ridge National Laboratory was presented at the American Geophysical Union's annual meeting in San Francisco on Friday, Dec. 15, 2000. Oceanic phytoplankton remove nearly as much carbon from the atmosphere each year as all land-based plants. Identifying the location and size of nutrient-limited areas in the open ocean has challenged oceanographers for nearly a century. The study pinpointed iron-limited regions by seeing which phytoplankton-rich areas of the world's oceans were also areas that received iron from wind-blown dust. In this map, areas with high levels of chlorophyll from phytoplankton and high levels of dust deposition (high correlation coefficients) are indicated in dark brown. Dust deposition was calculated by a 3-year modelled climatology for the years 1996-1998. The chlorophyll measurements are from 1998 observations from the SeaWiFS (Sea-viewing Wide Field-of-view Sensor) instrument on the OrbView-2 satellite. 'Global, satellite-based analyses such as this gives us insight into where iron deposition may be limiting ocean biological activity,' says lead author David Erickson of Oak Ridge National Laboratory's Computer Science and Mathematics Division. 'With this information we will be able to infer how the ocean productivity/iron deposition relationship might shift in response to climate change.' Map Source: David Erickson, Oak Ridge National Laboratory's Computer Science and Mathematics Division

  13. New View of Gas and Dust in the Solar Nebula

    NASA Astrophysics Data System (ADS)

    Taylor, G. J.

    2010-08-01

    The recognizable components in meteorites differ in their relative abundances of the three oxygen isotopes (16O, 17O, and 18O). In particular, the amount of 16O varies from being like that of the Earth to substantially enriched compared to the other two isotopes. The current explanation for this interesting range in isotopic composition is that dust and gas in the solar nebula (the cloud of gas and dust surrounding the primitive Sun) began with the same 16O-rich composition, but the solids evolved towards the terrestrial value. A new analysis of the problem by Alexander Krot (University of Hawaii) and colleagues at the University of Hawaii, the University of Chicago, Clemson University, and Lawrence Livermore National Laboratory leads to the bold assertion that primordial dust and gas differed in isotopic composition. The gas was rich in 16O as previously thought (possibly slightly richer in 16O than the measurements of the solar wind returned by the Genesis Mission), but that the dust had a composition close to the 16O-depleted terrestrial average. In this new view, the dust had a different history than did the gas before being incorporated into the Solar System. Solids with compositions near the terrestrial line may have formed in regions of the solar nebula where dust had concentrated compared to the mean solar dust/gas ratio (1 : ~100). The idea has great implications for understanding the oxygen-isotope composition of the inner Solar System and the origin of materials in the molecular cloud from which the Solar System formed.

  14. The impact of mineral dust on regional tropical circulation

    NASA Astrophysics Data System (ADS)

    Bangalath, H.; Stenchikov, G. L.

    2012-12-01

    Dust aerosols from the West Asian and African subtropical deserts likely play an important role in regional low-latitude circulation patterns. These aerosols both absorb solar and terrestrial radiation and reflect solar radiation and therefore both cool the surface and warm the lower troposphere. Since the distribution of dust is spatially non-uniform, its cooling/heating effect could significantly disturb regional temperature and pressure fields and affect tropical circulation patterns, including the Hadley and Walker Cells, as well as the Monsoon Circulation. Here, we investigate the direct radiative effect of desert dust on the circulation over the Middle East and North Africa (MENA) and South Asia regions using the high-resolution atmospheric general circulation model (HiRAM) developed at the NOAA Geophysical Fluid Dynamics Laboratory. We conducted simulations with and without dust aerosols with a spatial resolution of 25 km globally, which allowed investigation of the regional features of the tropical circulations and their interactions with global-scale processes. Our analysis of the 200 hPa velocity potential indicated that mineral dust increased the strength of the Hadley Cell. In general, the Hadley, Walker, and Monsoon circulations over the African continent and East Atlantic were intensified by the dust effect, whereas we observed the opposite response over the Pacific. An anomalous strengthening of the wind convergence at the northern border of the Hadley cell over the African continent and in the East Atlantic, especially in the summer, became evident from our simulations. We found that dust aerosols play an important role in the formation of the climate and circulation regimes over MENA and South Asia, suggesting that they should be accounted for in future climate projections.

  15. Development of automatic movement analysis system for a small laboratory animal using image processing

    NASA Astrophysics Data System (ADS)

    Nagatomo, Satoshi; Kawasue, Kikuhito; Koshimoto, Chihiro

    2013-03-01

    Activity analysis in a small laboratory animal is an effective procedure for various bioscience fields. The simplest way to obtain animal activity data is just observation and recording manually, even though this is labor intensive and rather subjective. In order to analyze animal movement automatically and objectivity, expensive equipment is usually needed. In the present study, we develop animal activity analysis system by means of a template matching method with video recorded movements in laboratory animal at a low cost.

  16. Multiwavelength analysis for interferometric (sub-)mm observations of protoplanetary disks. Radial constraints on the dust properties and the disk structure

    NASA Astrophysics Data System (ADS)

    Tazzari, M.; Testi, L.; Ercolano, B.; Natta, A.; Isella, A.; Chandler, C. J.; Pérez, L. M.; Andrews, S.; Wilner, D. J.; Ricci, L.; Henning, T.; Linz, H.; Kwon, W.; Corder, S. A.; Dullemond, C. P.; Carpenter, J. M.; Sargent, A. I.; Mundy, L.; Storm, S.; Calvet, N.; Greaves, J. A.; Lazio, J.; Deller, A. T.

    2016-04-01

    Context. The growth of dust grains from sub-μm to mm and cm sizes is the first step towards the formation of planetesimals. Theoretical models of grain growth predict that dust properties change as a function of disk radius, mass, age, and other physical conditions. High angular resolution observations at several (sub-)mm wavelengths constitute the ideal tool with which to directly probe the bulk of dust grains and to investigate the radial distribution of their properties. Aims: We lay down the methodology for a multiwavelength analysis of (sub-)mm and cm continuum interferometric observations to self-consistently constrain the disk structure and the radial variation of the dust properties. The computational architecture is massively parallel and highly modular. Methods: The analysis is based on the simultaneous fit in the uv-plane of observations at several wavelengths with a model for the disk thermal emission and for the dust opacity. The observed flux density at the different wavelengths is fitted by posing constraints on the disk structure and on the radial variation of the grain size distribution. Results: We apply the analysis to observations of three protoplanetary disks (AS 209, FT Tau, DR Tau) for which a combination of spatially resolved observations in the range ~0.88 mm to ~10 mm is available from SMA, CARMA, and VLA. In these disks we find evidence of a decrease in the maximum dust grain size, amax, with radius. We derive large amax values up to 1 cm in the inner disk 15 AU ≤ R ≤ 30 AU and smaller grains with amax ~ 1 mm in the outer disk (R ≳ 80 AU). Our analysis of the AS 209 protoplanetary disk confirms previous literature results showing amax decreasing with radius. Conclusions: Theoretical studies of planetary formation through grain growth are plagued by the lack of direct information on the radial distribution of the dust grain size. In this paper we develop a multiwavelength analysis that will allow this missing quantity to be

  17. Effects of obliqueness and strong electrostatic interaction on linear and nonlinear propagation of dust-acoustic waves in a magnetized strongly coupled dusty plasma

    SciTech Connect

    Shahmansouri, M.; Mamun, A. A.

    2014-03-15

    Linear and nonlinear propagation of dust-acoustic waves in a magnetized strongly coupled dusty plasma is theoretically investigated. The normal mode analysis (reductive perturbation method) is employed to investigate the role of ambient/external magnetic field, obliqueness, and effective electrostatic dust-temperature in modifying the properties of linear (nonlinear) dust-acoustic waves propagating in such a strongly coupled dusty plasma. The effective electrostatic dust-temperature, which arises from strong electrostatic interactions among highly charged dust, is considered as a dynamical variable. The linear dispersion relation (describing the linear propagation characteristics) for the obliquely propagating dust-acoustic waves is derived and analyzed. On the other hand, the Korteweg-de Vries equation describing the nonlinear propagation of the dust-acoustic waves (particularly, propagation of dust-acoustic solitary waves) is derived and solved. It is shown that the combined effects of obliqueness, magnitude of the ambient/external magnetic field, and effective electrostatic dust-temperature significantly modify the basic properties of linear and nonlinear dust-acoustic waves. The results of this work are compared with those observed by some laboratory experiments.

  18. Dust Charging and Transport on Surfaces

    SciTech Connect

    Wang, X.; Robertson, S.; Horanyi, M.

    2011-11-29

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

  19. Dust observations at orbital altitudes surrounding Mars.

    PubMed

    Andersson, L; Weber, T D; Malaspina, D; Crary, F; Ergun, R E; Delory, G T; Fowler, C M; Morooka, M W; McEnulty, T; Eriksson, A I; Andrews, D J; Horanyi, M; Collette, A; Yelle, R; Jakosky, B M

    2015-11-06

    Dust is common close to the martian surface, but no known process can lift appreciable concentrations of particles to altitudes above ~150 kilometers. We present observations of dust at altitudes ranging from 150 to above 1000 kilometers by the Langmuir Probe and Wave instrument on the Mars Atmosphere and Volatile Evolution spacecraft. Based on its distribution, we interpret this dust to be interplanetary in origin. A comparison with laboratory measurements indicates that the dust grain size ranges from 1 to 12 micrometers, assuming a typical grain velocity of ~18 kilometers per second. These direct observations of dust entering the martian atmosphere improve our understanding of the sources, sinks, and transport of interplanetary dust throughout the inner solar system and the associated impacts on Mars's atmosphere.

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

    NASA Astrophysics Data System (ADS)

    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.

  1. The Analysis of Seawater: A Laboratory-Centered Learning Project in General Chemistry.

    ERIC Educational Resources Information Center

    Selco, Jodye I.; Roberts, Julian L., Jr.; Wacks, Daniel B.

    2003-01-01

    Describes a sea-water analysis project that introduces qualitative and quantitative analysis methods and laboratory methods such as gravimetric analysis, potentiometric titration, ion-selective electrodes, and the use of calibration curves. Uses a problem-based cooperative teaching approach. (Contains 24 references.) (YDS)

  2. A Comparative Study Of Dust Devils

    NASA Astrophysics Data System (ADS)

    Lange, C. F.; Prieto, L. E.

    2005-12-01

    computational models. This was accomplished by examining features of the dust devils in the form of three main flow parameters: the ratio of the inflow layer height h to the updraft radius r_0 (aspect ratio), the radial Reynolds number characterizing the updraft zone, and the ratio of the tangential velocity to the mean radial velocity (swirl ratio) at the radius of the updraft zone, r_0. The detailed analysis of the numerical flow solutions led to a simple definition of h and r_0, valid for the types of model flows analyzed. This study is a necessary part of a larger effort to examine and compare both numerical and laboratory simulations of atmospheric vortices in terrestrial and Martian conditions. References [1] R. Greeley et al., XXXII Lunar and Planetary Science, 2001. [2] D. E. Lund and J. T. Snow, The Tornado: Its Structure, Dynamics, Prediction, and Hazards, 1993, p. 297--306. [3] N. B. Ward, J. Atmos. Sci., 1972, 1194--1204.

  3. A~comprehensive parameterization of heterogeneous ice nucleation of dust surrogate: laboratory study with hematite particles and its application to atmospheric models

    NASA Astrophysics Data System (ADS)

    Hiranuma, N.; Paukert, M.; Steinke, I.; Zhang, K.; Kulkarni, G.; Hoose, C.; Schnaiter, M.; Saathoff, H.; Möhler, O.

    2014-06-01

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

  4. Planck intermediate results. L. Evidence of spatial variation of the polarized thermal dust spectral energy distribution and implications for CMB B-mode analysis

    NASA Astrophysics Data System (ADS)

    Planck Collaboration; Aghanim, N.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Ballardini, M.; Banday, A. J.; Barreiro, R. B.; Bartolo, N.; Basak, S.; Benabed, K.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bonaldi, A.; Bonavera, L.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Boulanger, F.; Bracco, A.; Burigana, C.; Calabrese, E.; Cardoso, J.-F.; Chiang, H. C.; Colombo, L. P. L.; Combet, C.; Comis, B.; Crill, B. P.; Curto, A.; Cuttaia, F.; Davis, R. J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.-M.; Di Valentino, E.; Dickinson, C.; Diego, J. M.; Doré, O.; Douspis, M.; Ducout, A.; Dupac, X.; Dusini, S.; Efstathiou, G.; Elsner, F.; Enßlin, T. A.; Eriksen, H. K.; Falgarone, E.; Fantaye, Y.; Finelli, F.; Frailis, M.; Fraisse, A. A.; Franceschi, E.; Frolov, A.; Galeotta, S.; Galli, S.; Ganga, K.; Génova-Santos, R. T.; Gerbino, M.; Ghosh, T.; Giard, M.; González-Nuevo, J.; Górski, K. M.; Gregorio, A.; Gruppuso, A.; Gudmundsson, J. E.; Hansen, F. K.; Helou, G.; Herranz, D.; Hivon, E.; Huang, Z.; Jaffe, A. H.; Jones, W. C.; Keihänen, E.; Keskitalo, R.; Kisner, T. S.; Krachmalnicoff, N.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lähteenmäki, A.; Lamarre, J.-M.; Lasenby, A.; Lattanzi, M.; Lawrence, C. R.; Le Jeune, M.; Levrier, F.; Liguori, M.; Lilje, P. B.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maggio, G.; Maino, D.; Mandolesi, N.; Mangilli, A.; Maris, M.; Martin, P. G.; Martínez-González, E.; Matarrese, S.; Mauri, N.; McEwen, J. D.; Melchiorri, A.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschênes, M.-A.; Molinari, D.; Moneti, A.; Montier, L.; Morgante, G.; Moss, A.; Naselsky, P.; Nørgaard-Nielsen, H. U.; Oxborrow, C. A.; Pagano, L.; Paoletti, D.; Partridge, B.; Patrizii, L.; Perdereau, O.; Perotto, L.; Pettorino, V.; Piacentini, F.; Plaszczynski, S.; Polenta, G.; Puget, J.-L.; Rachen, J. P.; Reinecke, M.; Remazeilles, M.; Renzi, A.; Rocha, G.; Rossetti, M.; Roudier, G.; Rubiño-Martín, J. A.; Ruiz-Granados, B.; Salvati, L.; Sandri, M.; Savelainen, M.; Scott, D.; Sirignano, C.; Sirri, G.; Stanco, L.; Suur-Uski, A.-S.; Tauber, J. A.; Tenti, M.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Trombetti, T.; Valiviita, J.; Vansyngel, F.; Van Tent, F.; Vielva, P.; Wandelt, B. D.; Wehus, I. K.; Zacchei, A.; Zonca, A.

    2017-02-01

    The characterization of the Galactic foregrounds has been shown to be the main obstacle in thechallenging quest to detect primordial B-modes in the polarized microwave sky. We make use of the Planck-HFI 2015 data release at high frequencies to place new constraints on the properties of the polarized thermal dust emission at high Galactic latitudes. Here, we specifically study the spatial variability of the dust polarized spectral energy distribution (SED), and its potential impact on the determination of the tensor-to-scalar ratio, r. We use the correlation ratio of the angular power spectra between the 217 and 353 GHz channels as a tracer of these potential variations, computed on different high Galactic latitude regions, ranging from 80% to 20% of the sky. The new insight from Planck data is a departure of the correlation ratio from unity that cannot be attributed to a spurious decorrelation due to the cosmic microwave background, instrumental noise, or instrumental systematics. The effect is marginally detected on each region, but the statistical combination of all the regions gives more than 99% confidence for this variation in polarized dust properties. In addition, we show that the decorrelation increases when there is a decrease in the mean column density of the region of the sky being considered, and we propose a simple power-law empirical model for this dependence, which matches what is seen in the Planck data. We explore the effect that this measured decorrelation has on simulations of the BICEP2-Keck Array/Planck analysis and show that the 2015 constraints from these data still allow a decorrelation between the dust at 150 and 353 GHz that is compatible with our measured value. Finally, using simplified models, we show that either spatial variation of the dust SED or of the dust polarization angle are able to produce decorrelations between 217 and 353 GHz data similar to the values we observe in the data.

  5. Recombinant factor C (rFC) assay and gas chromatography/mass spectrometry (GC/MS) analysis of endotoxin variability in four agricultural dusts.

    PubMed

    Saito, Rena; Cranmer, Brian K; Tessari, John D; Larsson, Lennart; Mehaffy, John M; Keefe, Thomas J; Reynolds, Stephen J

    2009-10-01

    Endotoxin exposure is a significant concern in agricultural environments due to relatively high exposure levels. The goals of this study were to determine patterns of 3-hydroxy fatty acid (3-OHFA) distribution in dusts from four types of agricultural environments (dairy, cattle feedlot, grain elevator, and corn farm) and to evaluate correlations between the results of gas chromatography/mass spectrometry (GC/MS) analysis (total endotoxin) and biological recombinant factor C (rFC) assay (free bioactive endotoxin). An existing GC/MS-MS method (for house dust) was modified to reduce sample handling and optimized for small amount (<1 mg) of agricultural dusts using GC/EI-MS. A total of 134 breathing zone samples using Institute of Occupational Medicine (IOM) inhalable samplers were collected from agricultural workers in Colorado and Nebraska. Livestock dusts contained approximately two times higher concentrations of 3-OHFAs than grain dusts. Patterns of 3-OHFA distribution and proportion of each individual 3-OHFA varied by dust type. The rank order of Pearson correlations between the biological rFC assay and the modified GC/EI-MS results was feedlot (0.72) > dairy (0.53) > corn farm (0.33) > grain elevator (0.11). In livestock environments, both odd- and even-numbered carbon chain length 3-OHFAs correlated with rFC assay response. The GC/EI-MS method should be especially useful for identification of specific 3-OHFAs for endotoxins from various agricultural environments and may provide useful information for evaluating the relationship between bacterial exposure and respiratory disease among agricultural workers.

  6. Mineralogical properties and