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Sample records for dust lead loadings

  1. A survey of spatially distributed exterior dust lead loadings in New York City

    SciTech Connect

    Caravanos, Jack; Weiss, Arlene L.; Blaise, Marc J.; Jaeger, Rudolph J. . E-mail: jaegerr@envmed.com

    2006-02-15

    This work documents ambient lead dust deposition values (lead loading) for the boroughs of New York City in 2003-2004. Currently, no regulatory standards exist for exterior concentrations of lead in settled dust. This is in contrast to the clearance and risk assessment standards that exist for interior residential dust. The reported potential for neurobehavioral toxicity and adverse cognitive development in children due to lead exposure prompts public health concerns about undocumented lead sources. Such sources may include settled dust of outdoor origin. Dust sampling throughout the five boroughs of NYC was done from the top horizontal portion of pedestrian traffic control signals (PTCS) at selected street intersections along main thoroughfares. The data (n=214 samples) show that lead in dust varies within each borough with Brooklyn having the highest median concentration (730{mu}g/ft{sup 2}), followed in descending order by Staten Island (452{mu}g/ft{sup 2}), the Bronx (382{mu}g/ft{sup 2}), Queens (198{mu}g/ft{sup 2}) and finally, Manhattan (175{mu}g/ft{sup 2}). When compared to the HUD/EPA indoor lead in dust standard of 40{mu}g/ft{sup 2}, our data show that this value is exceeded in 86% of the samples taken. An effort was made to determine the source of the lead in the dust atop of the PTCS. The lead in the dust and the yellow signage paint (which contains lead) were compared using isotopic ratio analysis. Results showed that the lead-based paint chip samples from intact signage did not isotopically match the dust wipe samples taken from the same surface. We know that exterior dust containing lead contributes to interior dust lead loading. Therefore, settled leaded dust in the outdoor environment poses a risk for lead exposure to children living in urban areas, namely, areas with elevated childhood blood lead levels and background lead dust levels from a variety of unidentified sources.

  2. Seasonal variations of lead concentration and loading rates in residential house dust in northern Idaho.

    PubMed

    Petrosyan, Varduhi; von Braun, Margrit C; Spalinger, Susan M; von Lindern, Ian H

    2006-04-30

    Although lead hazards to humans have been known since ancient times and many regulatory actions and lead risk reductions have been achieved over the past century, lead contamination and exposure remain significant problems worldwide. The focus of this study was to investigate whether residential house dust lead concentrations and lead and dust loading rates in non-contaminated or "background" communities in northern Idaho are significantly affected by seasonal variations. House dust samples were obtained from 34 houses in five towns of northern Idaho from March to November 1999. There was evidence of significant seasonality of lead concentration in house dust in some towns, but no evidence in other towns. Because of the high variability between the towns and small sample sizes, it was difficult to make firm conclusions about seasonal patterns observed in house dust lead levels. A linear relationship between precipitation rates and dust loading rates was detected.

  3. The global atmospheric loading of dust aerosols

    NASA Astrophysics Data System (ADS)

    Kok, J. F.; Ridley, D. A.; Haustein, K.; Miller, R. L.; Zhao, C.

    2015-12-01

    Mineral dust is one of the most ubiquitous aerosols in the atmosphere, with important effects on human health and the climate system. But despite its importance, the global atmospheric loading of dust has remained uncertain, with model results spanning about a factor of five. Here we constrain the particle size-resolved atmospheric dust loading and global emission rate, using a novel theoretical framework that uses experimental constraints on the optical properties and size distribution of dust to eliminate climate model errors due to assumed dust properties. We find that most climate models underestimate the global atmospheric loading and emission rate of dust aerosols.

  4. Chemical speciation of lead dust associated with primary lead smelting.

    PubMed Central

    Spear, T M; Svee, W; Vincent, J H; Stanisich, N

    1998-01-01

    The research presented in this article assessed geochemical factors relating to dust produced during primary lead smelting. Bulk dust samples and size-selective airborne dust samples were collected from four areas of a primary lead smelter and analyzed by X-ray diffraction and sequential chemical extraction. X-ray diffraction showed that the smelter dusts were composed primarily of sulfides, oxides, sulfates, and silicates of metal ores, with galena being the primary dust component. Sequential extraction revealed the solubility of lead compounds at less than 7% in the exchangeable and mildly acidic steps for the bulk dusts collected from four smelter areas. The later steps of the extraction procedure were more effective in dissolving the lead compounds associated with the bulk dust samples, with 43%, 26%, and 8% of the total lead, in the ore storage, sinter, and blast/dross smelter areas, respectively, being extracted in the residual step. Sequential extraction of coarse airborne dust samples from the ore storage and sinter plant showed that 1.2% and 4.1% of the total lead, respectively, was exchangeable. The finer particle size fractions from these areas of the smelter showed higher percentages of exchangeable lead. Of the course airborne dust from the blast/dross furnace processes, 65% of the total lead was exchangeable. However, the largest percentage of lead from these areas was associated with the finer particle-size fractions. If lead bioavailability is related to its solubility as determined through sequential extraction, the health hazards associated with lead exposure may be appreciably enhanced in the blast and dross furnace processes. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 PMID:9721256

  5. Contribution of lead in dust to children's blood lead.

    PubMed Central

    Duggan, M J

    1983-01-01

    The importance of urban dust as a source of lead for young children is still disputed. Although blood-lead data from various population surveys usually show a peak concentration in early childhood, there is evidence that such a peak is small or absent altogether in children without much access to the general environment. An examination of those studies where groups of people in regions of low and high lead contamination have been compared shows that the child/adult blood-lead ratio is almost always enhanced in the more exposed groups. This implies a route of lead uptake which is important for children but less so for adults, and it is likely that this route is the dust-hand-mouth one. There are sufficient data to suggest a quantitative relationship between raised levels of blood lead and lead in dust. There is a strong case for a lead-in-dust standard but some will probably remain unpersuaded unless or until there are reliable data for blood lead and environmental lead involving matched groups of young people from urban and rural areas. PMID:6873030

  6. Amplification of dust loading in Martian dust devils by self-shadowing

    NASA Astrophysics Data System (ADS)

    Kuepper, M.; Wurm, G.

    2016-08-01

    Insolation of the Martian soil leads to a sub-surface overpressure due to thermal creep gas flow. This could support particle entrainment into the atmosphere. Short time shadowing e.g. by the traverse of a larger dust devil would enhance this effect. We find in microgravity experiments that mass ejection rates are increased by a factor of 10 for several seconds if a light source of 12.6 kW/m2 is turned off. Scaled to Mars this implies that self-shadowing of a partially opaque dust devil might lead to a strongly amplified flux of lifted material. We therefore suggest that self-shadowing might be a mechanism on Mars to increase the total dust loading of a dust devil and keep it self-sustained.

  7. Northern Idaho house dust and soil lead levels compared to the Bunker Hill Superfund Site.

    PubMed

    Spalinger, Susan M; von Braun, Margrit C; Petrosyan, Varduhi; von Lindern, Ian H

    2007-07-01

    House dust has been identified as a major exposure medium for lead (Pb) in children. High levels of Pb in soil and house dust have been recorded at the Bunker Hill Superfund Site (BHSS) in northern Idaho, an historic mining and smelting district. Soil and dust remediation at the site was required; however, regional background soil and dust Pb levels had not been well characterized. The objective of this survey was to determine background house dust Pb levels and to compare those levels with concentrations, and dust and Pb loading rates measured at the BHSS. Soil and house dust samples were collected in five towns demographically similar to the BHSS but unaffected by the mining industry. The background concentrations and loading rates were significantly lower than those observed at the site. House age was a significant factor affecting background soil and house dust Pb concentrations and loading rates.

  8. Lead dust in Broken Hill homes: effect of remediation on indoor lead levels.

    PubMed

    Boreland, F; Lyle, D M

    2006-02-01

    This study was undertaken to determine whether home remediation effectively reduced indoor lead levels in Broken Hill, a long-established silver-lead-zinc mining town in outback Australia. A before-after study of the effect of home remediation on indoor lead levels was embedded into a randomized controlled trial of the effectiveness of remediation for reducing elevated blood lead levels in young children. Moist towelettes were used to measure lead loading (microg/m2) on internal windowsills and internal and entry floors of 98 homes; samples were collected before, immediately after, and 2, 4, 6, 8, and 10 months after remediation. Data were log(10) transformed for the analysis. Remediation reduced average indoor lead levels by approximately 50%, and lead levels remained low for the duration of the follow-up period (10 months). The greatest gains were made in homes with the highest initial lead levels; homes with low preremediation lead levels showed little or no benefit. Before remediation, homes located in areas with high soil lead levels or with "poor" dust proofing had higher lead levels than those in areas with lower soil lead levels or with "medium" or "good" dust proofing; these relative differences remained after remediation. There was no evidence that lead loading was reduced by an increased opportunity to become aware of lead issues. We conclude that remediation is an effective strategy for reducing the lead exposure of children living in homes with high indoor lead levels.

  9. The contribution of lead-contaminated house dust and residential soil to children`s blood lead levels

    SciTech Connect

    Lanphear, B.P.; Matte, T.D.; Rogers, J.

    1998-10-01

    In 1992, the US Congress passed the Residential Lead-Based Paint Hazard Reduction Act, which requires the promulgation of health-based dust lead and soil lead standards for residential dwellings to prevent undue lead exposure in children. Unfortunately, the levels of lead in house dust and soil that are associated with elevated blood lead levels among US children remain poorly defined. This pooled analysis was done to estimate the contributions of lead-contaminated house dust and soil to children`s blood lead levels. The results of this pooled analysis, the most comprehensive existing epidemiologic analysis of childhood lead exposure, confirm that lead-contaminated house dust is the major source of lead exposure for children. These analyses further demonstrate that a strong relationship between interior dust lead loading and children`s blood lead levels persists at dust lead levels considerably below the US Department of Housing and urban Development`s current post-abatement standards and the Environmental Protection Agency`s guidance levels. Finally, these analyses demonstrate that a child`s age, race, mouthing behaviors, and study-site specific factors influence the predicted blood lead level at a given level of exposure. These data can be used to estimate the potential health impact of alternative health-based lead standards for residential sources of lead exposure.

  10. DEVELOPING AND IMPLEMENTING A LEAD DUST MONITORING, OUTREACH AND EDUCATION PROGRAM IN YOUR COMMUNITY/SYRACUSE LEAD DUST PROJECT

    EPA Science Inventory

    EPA has developed a technology transfer document (case-study) for the EMPACT Syracuse Lead Dust Project. The Lead Dust Project is designed to measure the lead dust content in homes and public buildings within the City of Syracuse, NY. The project also contains an educational comp...

  11. DEVELOPING AND IMPLEMENTING A LEAD DUST MONITORING, OUTREACH AND EDUCATION PROGRAM IN YOUR COMMUNITY/SYRACUSE LEAD DUST PROJECT

    EPA Science Inventory

    EPA has developed a technology transfer document (case-study) for the EMPACT Syracuse Lead Dust Project. The Lead Dust Project is designed to measure the lead dust content in homes and public buildings within the City of Syracuse, NY. The project also contains an educational comp...

  12. A study of urban housing demolitions as sources of lead in ambient dust: demolition practices and exterior dust fall.

    PubMed Central

    Farfel, Mark R; Orlova, Anna O; Lees, Peter S J; Rohde, Charles; Ashley, Peter J; Chisolm, J Julian

    2003-01-01

    Demolition of older housing for urban redevelopment purposes benefits communities by removing housing with lead paint and dust hazards and by creating spaces for lead paint-free housing and other community resources. This study was conducted to assess changes, if any, in ambient dust lead levels associated with demolition of blocks of older lead-containing row houses in Baltimore, Maryland (USA). In this article we present results based on dust-fall samples collected from fixed locations within 10 m of three demolition sites. In subsequent reports we will describe dust lead changes on streets, sidewalks, and residential floors within 100 m of the demolition sites. Geometric mean (GM) lead dust-fall rate increased by > 40-fold during demolition to 410 micro g Pb/m2/hr (2,700 micro g Pb/m2 per typical work day) and by > 6-fold during debris removal to 61 micro g Pb/m2/hr (440 micro g Pb/m2 per typical work day). Lead concentrations in dust fall also increased during demolition (GM, 2,600 mg/kg) and debris removal (GM, 1,500 mg/kg) compared with baseline (GM, 950 mg/kg). In the absence of dust-fall standards, the results were compared with the U.S. Environmental Protection Agency's (U.S. EPA's) dust-lead surface loading standard for interior residential floors (40 micro g/ft2, equivalent to 431 micro g/m2); daily lead dust fall during demolition exceeded the U.S. EPA floor standard by 6-fold on average and as much as 81-fold on an individual sample basis. Dust fall is of public health concern because it settles on surfaces and becomes a pathway of ambient lead exposure and a potential pathway of residential exposure via tracking and blowing of exterior dust. The findings highlight the need to minimize demolition lead deposition and to educate urban planners, contractors, health agencies, and the public about lead and other community concerns so that society can maximize the benefits of future demolition activities nationwide. PMID:12842778

  13. A study of urban housing demolitions as sources of lead in ambient dust: demolition practices and exterior dust fall.

    PubMed

    Farfel, Mark R; Orlova, Anna O; Lees, Peter S J; Rohde, Charles; Ashley, Peter J; Chisolm, J Julian

    2003-07-01

    Demolition of older housing for urban redevelopment purposes benefits communities by removing housing with lead paint and dust hazards and by creating spaces for lead paint-free housing and other community resources. This study was conducted to assess changes, if any, in ambient dust lead levels associated with demolition of blocks of older lead-containing row houses in Baltimore, Maryland (USA). In this article we present results based on dust-fall samples collected from fixed locations within 10 m of three demolition sites. In subsequent reports we will describe dust lead changes on streets, sidewalks, and residential floors within 100 m of the demolition sites. Geometric mean (GM) lead dust-fall rate increased by > 40-fold during demolition to 410 micro g Pb/m2/hr (2,700 micro g Pb/m2 per typical work day) and by > 6-fold during debris removal to 61 micro g Pb/m2/hr (440 micro g Pb/m2 per typical work day). Lead concentrations in dust fall also increased during demolition (GM, 2,600 mg/kg) and debris removal (GM, 1,500 mg/kg) compared with baseline (GM, 950 mg/kg). In the absence of dust-fall standards, the results were compared with the U.S. Environmental Protection Agency's (U.S. EPA's) dust-lead surface loading standard for interior residential floors (40 micro g/ft2, equivalent to 431 micro g/m2); daily lead dust fall during demolition exceeded the U.S. EPA floor standard by 6-fold on average and as much as 81-fold on an individual sample basis. Dust fall is of public health concern because it settles on surfaces and becomes a pathway of ambient lead exposure and a potential pathway of residential exposure via tracking and blowing of exterior dust. The findings highlight the need to minimize demolition lead deposition and to educate urban planners, contractors, health agencies, and the public about lead and other community concerns so that society can maximize the benefits of future demolition activities nationwide.

  14. Lead in Chinese villager house dust

    NASA Astrophysics Data System (ADS)

    Bi, Xiangyang; Liu, Jinling; Han, Zhixuan

    2016-04-01

    House dust has been recognized as an important contributor to children's blood Pb. Here we conducted a comprehensive study to investigate geographical variation of Pb in Chinese villager house dust. The concentrations of Pb in 477 house dust samples collected from twenty eight areas throughout China varied from 12 to 2510 mg/kg, with geometric mean and median concentration of 54 mg/kg and 42 mg/kg, respectively. The median Pb concentrations in different geographical areas ranged from 16 (Zhangjiakou, Hebei) to 195 mg/kg (Loudi, Hunan). The influences of outdoor soil Pb concentrations, dates of construction, house decorative materials, heating types, and site specific pollution on Pb concentrations in house dust were evaluated. No correlations were found between the house dust Pb concentrations and the age of houses, as well as house decorative materials. Whereas outdoor soil, coal combustion, and site specific pollution may be potential Pb sources. The results of scanning electron microscopy (SEM) showed that Pb bearing particles appeared as cylindrical, flaky and irregular aggregates with the particle size ranging from about 10 to 800 μm. The energy dispersive X-ray microanalysis (EDX) suggested that Pb in the dust particles may be associated with calcium compounds. But the major fraction of Pb in the household dust samples was found to be strongly bound to Fe-Mn oxide phases (37%) while Pb present in minor fractions individually making up between 14 and 18% was characterized in falling order as residual, carbonate, organic/sulphide and exchangeable fractions by the sequential extraction method applied. Bioaccessible Pb making up an average proportion of 53% in the household dusts was significantly correlated to the Fe-Mn oxide phases of Pb.

  15. Volcanic loading: The dust veil index

    SciTech Connect

    Lamb, H.H.

    1985-09-01

    Dust ejected into the high atmosphere during explosive volcanic eruptions has been considered as a possible cause for climatic change. Dust veils created by volcanic eruptions can reduce the amount of light reaching the Earth`s surface and can cause reductions in surface temperatures. These climatic effects can be seen for several years following some eruptions and the magnitude and duration of the effects depend largely on the density or amount of tephra (i.e. dust) ejected, the latitude of injection, and atmospheric circulation patterns. Lamb (1970) formulated the Dust Veil Index (DVI) in an attempt to quantify the impact on the Earth`s energy balance of changes in atmospheric composition due to explosive volcanic eruptions. The DVI is a numerical index that quantifies the impact on the Earth`s energy balance of changes in atmospheric composition due to explosive volcanic eruptions. The DVI is a numerical index that quantifies the impact of a particular volcanic eruptions release of dust and aerosols over the years following the event. The DVI for any volcanic eruptions are available and have been used in estimating Lamb`s dust veil indices.

  16. Lead loading of urban streets by motor vehicle wheel weights.

    PubMed

    Root, R A

    2000-10-01

    This study documents that lead weights, which are used to balance motor vehicle wheels, are lost and deposited in urban streets, that they accumulate along the outer curb, and that they are rapidly abraded and ground into tiny pieces by vehicle traffic. The lead is so soft that half the lead deposited in the street is no longer visible after little more than 1 week. This lead loading of urban streets by motor vehicle wheel weights is continuous, significant, and widespread, and is potentially a major source of human lead exposure because the lead is concentrated along the outer curb where pedestrians are likely to step. Lead deposition at one intersection in Albuquerque, New Mexico, ranged from 50 to 70 kg/km/year (almost 11 g/ft(2)/year along the outer curb), a mass loading rate that, if accumulated for a year, would exceed federal lead hazard guidelines more than 10,000 times. Lead loading of major Albuquerque thoroughfares is estimated to be 3,730 kg/year. Wheel weight lead may be dispersed as fugitive dust, flushed periodically by storm water into nearby waterways and aquatic ecosystems, or may adhere to the shoes of pedestrians or the feet of pets, where it can be tracked into the home. I propose that lead from wheel weights contributes to the lead burden of urban populations.

  17. Lead loading of urban streets by motor vehicle wheel weights.

    PubMed Central

    Root, R A

    2000-01-01

    This study documents that lead weights, which are used to balance motor vehicle wheels, are lost and deposited in urban streets, that they accumulate along the outer curb, and that they are rapidly abraded and ground into tiny pieces by vehicle traffic. The lead is so soft that half the lead deposited in the street is no longer visible after little more than 1 week. This lead loading of urban streets by motor vehicle wheel weights is continuous, significant, and widespread, and is potentially a major source of human lead exposure because the lead is concentrated along the outer curb where pedestrians are likely to step. Lead deposition at one intersection in Albuquerque, New Mexico, ranged from 50 to 70 kg/km/year (almost 11 g/ft(2)/year along the outer curb), a mass loading rate that, if accumulated for a year, would exceed federal lead hazard guidelines more than 10,000 times. Lead loading of major Albuquerque thoroughfares is estimated to be 3,730 kg/year. Wheel weight lead may be dispersed as fugitive dust, flushed periodically by storm water into nearby waterways and aquatic ecosystems, or may adhere to the shoes of pedestrians or the feet of pets, where it can be tracked into the home. I propose that lead from wheel weights contributes to the lead burden of urban populations. PMID:11049812

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

    PubMed

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

    2012-03-01

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

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

    USGS Publications Warehouse

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

    2008-01-01

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

  20. [Estimation of pulmonary dust load using magnetic pneumography].

    PubMed

    Le Gros, V; Lemaigre, D; Suon, C; Pozzi, J P; Berthaud, P; Liot, F

    1988-01-01

    If an occupational history enables the identification of subjects at high risk from occupational disease, it yields no information on the individual dust level on account of very important inter-individual variations in pulmonary dust retention. Magnetopneumography is the only technique which enables pulmonary dust loads to be estimated on living subjects. The first measures of dust load by magnetopneumography made at the Ambroise Pare Hospital are reported. By knowing the magnetic properties of occupationally inhaled aero-contaminants, this technique is sensitive and non-invasive and enables the total pulmonary dust load to be estimated from the study of the residual magnetism in the ferromagnetic component of these aero-contaminants. A SQUID magnetometer measures this magnetism on 5 lines of the anterior surface of the thorax after overall magnetisation of the latter by an external magnetic field of 30 kA/m. Measurements were made on 18 male subjects: 5 non-exposed controls and 13 occupationally exposed subjects to these aero-contaminants. The dust load calculated was variable, 0 in the controls and between 0 and 3,065 mg in exposed subjects. For the first time measures were made in 4 dental technicians: their dust load was between 725 and 3,065 mg. The problems posed by this method are broached. Its principle objective is the surveillance of occupationally exposed population to these aero-contaminants of ferromagnetic composition. A decrease in the residual magnetic signal after the cessation of magnetisation was observed in keeping with the data of the literature. This phenomenon, recognised under the term of "relaxation", is evidence of the activity of alveolar macrophages.

  1. 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.

  2. Removal of lead contaminated dusts from hard surfaces.

    PubMed

    Lewis, Roger D; Condoor, Sridhar; Batek, Joe; Ong, Kee Hean; Backer, Denis; Sterling, David; Siria, Jeff; Chen, John J; Ashley, Peter

    2006-01-15

    Government guidelines have widely recommended trisodium phosphate (TSP) or "lead-specific" cleaning detergents for removal of lead-contaminated dust (LCD) from hard surfaces, such as floors and window areas. The purpose of this study was to determine if low-phosphate, non-lead-specific cleaners could be used to efficiently remove LCD from 3 types of surfaces (vinyl flooring, wood, and wallpaper). Laboratory methods were developed and validated for simulating the doping, embedding, and sponge cleaning of the 3 surface types with 4 categories of cleaners: lead-specific detergents, nonionic cleaners, anionic cleaners, and trisodium phosphate (TSP). Vinyl flooring and wood were worn using artificial means. Materials were ashed, followed by ultrasound extraction, and anodic stripping voltammetry (ASV). One-way analysis of variance approach was used to evaluate the surface and detergent effects. Surface type was found to be a significant factor in removal of lead (p < 0.001). Vinyl flooring cleaned better than wallpaper by over 14% and wood cleaned better than wallpaper by 13%. There was no difference between the cleaning action of vinyl flooring and wood. No evidence was found to support the use of TSP or lead-specific detergents over all-purpose cleaning detergents for removal of lead-contaminated dusts. No-phosphate, non-lead-specific detergents are effective in sponge cleaning of lead-contaminated hard surfaces and childhood lead prevention programs should consider recommending all-purpose household detergents for removal of lead-contaminated dust after appropriate vacuuming.

  3. Flue Dust Agglomeration in the Secondary Lead Industry

    NASA Astrophysics Data System (ADS)

    Schwitzgebel, Klaus

    1981-01-01

    A secondary lead smelter produces several tons of bag-house dust a day. Appropriate handling of this dust is mandatory to meet the proposed OSHA and EPA workroom and ambient standards. Dust agglomeration proved a successful approach. Dusts with a high concentration of PbCl2, or compounds containing PbCl2 can be agglomerated at much lower temperatures than samples with low PbCl2 concentrations. The chlorine sources are polyvinyl chloride (PVC) battery plate separators. Since PVC is used in Europe to a much greater extent than in the U.S., the composition of feedstock must be considered in equipment selection at U.S. secondary smelters. The vapor pressure characteristics of PbCl2 favor its evaporation at blast furnace temperatures. Condensation occurs in the gas cooling system. Recycling of baghouse dust leads to a buildup of PbCl2 in the smelter. Its removal from the system is eventually necessary through leaching, if charges with a high PVC content are processed.

  4. Dust loading in Gusev crater, Mars: Results from two active dust devil seasons

    NASA Astrophysics Data System (ADS)

    Waller, D. A.; Greeley, R.; Neakrase, L. D.; Landis, G. A.; Whelley, P.; Thompson, S. D.

    2009-12-01

    during Season One and resulted in an average of ~50 active dust devils/km2/sol extrapolated out to the LAZ while 103 dust devils were imaged during Season Two resulting in an average of ~5 active dust devils/km2/sol within the LAZ. This drop in dust devil frequency from one season to the next was coupled with a 50% decrease in the amount of dust loaded into the atmosphere during Season Two (~19 kg/km2/sol in Season One and ~10 kg/km2/sol in Season Two). Previous models indicate that the increased amount of dust in the atmosphere during the storm decreased the amount of solar insolation to the surface therefore also decreasing the surface heat flux. The rapidly decreasing surficial heat flux prevents the temperature lapse rate (change in temperature gradient with elevation) from becoming super-adiabatic and therefore causes the low-altitude atmospheric temperature profile to become too homogeneous to sustain convective plumes.

  5. Do new wipe materials outperform traditional lead dust cleaning methods?

    PubMed

    Lewis, Roger D; Ong, Kee Hean; Emo, Brett; Kennedy, Jason; Brown, Christopher A; Condoor, Sridhar; Thummalakunta, Laxmi

    2012-01-01

    Government guidelines have traditionally recommended the use of wet mopping, sponging, or vacuuming for removal of lead-contaminated dust from hard surfaces in homes. The emergence of new technologies, such as the electrostatic dry cloth and wet disposable clothes used on mopheads, for removal of dust provides an opportunity to evaluate their ability to remove lead compared with more established methods. The purpose of this study was to determine if relative differences exist between two new and two older methods for removal of lead-contaminated dust (LCD) from three wood surfaces that were characterized by different roughness or texture. Standard leaded dust, <75 μm, was deposited by gravity onto the wood specimens. Specimens were cleaned using an automated device. Electrostatic dry cloths (dry Swiffer), wet Swiffer cloths, paper shop towels with non-ionic detergent, and vacuuming were used for cleaning LCD from the specimens. Lead analysis was by anodic stripping voltammetry. After the cleaning study was conducted, a study of the coefficient of friction was performed for each wipe material. Analysis of variance was used to evaluate the surface and cleaning methods. There were significant interactions between cleaning method and surface types, p = 0.007. Cleaning method was found be a significant factor in removal of lead, p <0.001, indicating that effectiveness of each cleaning methods is different. However, cleaning was not affected by types of surfaces. The coefficient of friction, significantly different among the three wipes, is likely to influence the cleaning action. Cleaning method appears to be more important than texture in LCD removal from hard surfaces. There are some small but important factors in cleaning LCD from hard surfaces, including the limits of a Swiffer mop to conform to curved surfaces and the efficiency of the wetted shop towel and vacuuming for cleaning all surface textures. The mean percentage reduction in lead dust achieved by the

  6. Seasonal Variations in Dust Loading within Gale Crater, Mars

    NASA Astrophysics Data System (ADS)

    Moore, Casey; Moores, John; Smith, Christina L.; MSL Science Team

    2016-10-01

    The Mars Science Laboratory rover Curiosity has been exploring Gale Crater for more than two martian years. Such tenure allows seasonal variability of the weather record for the current era to be studied with aid from Mast Cameras (Mastcam), Navigation Cameras (Navcam) and Rover Environmental Monitoring Station (REMS). Dust is a key component in the Martian atmosphere which helps drive atmospheric circulation. As such, these three instruments are integral in the characterization of the dust-loading environment both within and above the crater. This study uses Navcam imagery and a digital terrain model provided from HRSC on Mars Express to derive geographical line-of-sight extinction (LOS-Ext) coefficients, a quantity that assesses dust loading local to the air within the crater and which reveals differences in dust loading along different lines of sight.We report two martian years worth of LOS-Ext at Gale Crater, covering Ls 210° in Mars year (MY) 31 to Ls 210° in MY33. All seasons have been observed twice with the only significant exception being a gap in data between Ls 270° - 315° in MY31 (early southern summer). Visibility conditions within the crater range from a few tens of km in spring and summer to over 100 km peaking around the winter solstice. The LOS-Ext record is also compared to the column extinction record derived from the Mastcam Tau observations. The first year shows a convergence of the two values around Ls 270° in MY31 and similar values around Ls 350° in MY31 and Ls 135° in MY32. Otherwise, during the first year of observation, the LOS-Ext has lower values than the Mastcam column extinction indicating two non-interacting atmospheric layers. In the second year, not only are similar values observed more frequently, the LOS-Ext coefficients have a global peak and overtake Mastcam column extinction during Ls 270° - 315° in MY32, which correspond to the missing timeframe from the previous year. As this season is prone to high wind speeds

  7. New Information on Lead in Dirt and Dust as Related to the Childhood Lead Problem

    PubMed Central

    Haar, Gary Ter; Aronow, Regine

    1974-01-01

    It has been known for many years that the eating of leaded paint is the prime cause of lead poisoning and elevated blood leads of children living in deteriorated housing. Recently, there has been speculation that children may eat dirt and dust contaminated with lead exhausted from cars and that this amount of ingested lead is sufficient to contribute significantly to the childhood lead problem. This paper reports on a twopart study conducted to evaluate the validity of the dirt-and-dust hypotheses. The first part of the study was made to determine the source of lead in dirt to which children are normally exposed. Dirt samples were taken in old urban areas around 18 painted frame houses and 18 houses of brick construction. Samples also were taken around seven old frame farmhouses remote from traffic. Based on the fact that lead concentrations in the dirt were similar in city and rural yards at corresponding distances from the houses, it is clear that nearly all of the lead in dirt around these houses is due to paint from the houses. Lead antiknock additives are therefore not a significant contributor to the lead content of dirt around houses where children usually play. The second part of the study used a naturally occurring radioactive tracer 210Pb to determine the relative amounts of dust and other lead-containing materials (e.g., paint) eaten by young children. This tracer is present in very low concentrations in paint and in significantly higher concentrations in fallout dust. Stable lead and 210Pb were analyzed in fecal material from eight children suspected of having elevated body burdens of lead and ten children living in good housing where lead poisoning is not a problem. The normal children averaged 4 μg Pb/g dry feces, with a range of 2 to 7. Of the eight children suspected of having elevated lead body burdens, two had fecal lead values within the normal range. However, the remaining six were 4 to 400 times as high. Despite these differences in fecal lead

  8. Influence of Dust Loading on Atmospheric Ionizing Radiation on Mars

    NASA Technical Reports Server (NTRS)

    Norman, Ryan B.; Gronoff, Guillaume; Mertens, Christopher J.

    2014-01-01

    Measuring the radiation environment at the surface of Mars is the primary goal of the Radiation Assessment Detector on the NASA Mars Science Laboratory's Curiosity rover. One of the conditions that Curiosity will likely encounter is a dust storm. The objective of this paper is to compute the cosmic ray ionization in different conditions, including dust storms, as these various conditions are likely to be encountered by Curiosity at some point. In the present work, the Nowcast of Atmospheric Ionizing Radiation for Aviation Safety model, recently modified for Mars, was used along with the Badhwar & O'Neill 2010 galactic cosmic ray model. In addition to galactic cosmic rays, five different solar energetic particle event spectra were considered. For all input radiation environments, radiation dose throughout the atmosphere and at the surface was investigated as a function of atmospheric dust loading. It is demonstrated that for galactic cosmic rays, the ionization depends strongly on the atmosphere profile. Moreover, it is shown that solar energetic particle events strongly increase the ionization throughout the atmosphere, including ground level, and can account for the radio blackout conditions observed by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument on the Mars Express spacecraft. These results demonstrate that the cosmic rays' influence on the Martian surface chemistry is strongly dependent on solar and atmospheric conditions that should be taken into account for future studies.

  9. Influence of dust loading on atmospheric ionizing radiation on Mars

    NASA Astrophysics Data System (ADS)

    Norman, Ryan B.; Gronoff, Guillaume; Mertens, Christopher J.

    2014-01-01

    Measuring the radiation environment at the surface of Mars is the primary goal of the Radiation Assessment Detector on the NASA Mars Science Laboratory's Curiosity rover. One of the conditions that Curiosity will likely encounter is a dust storm. The objective of this paper is to compute the cosmic ray ionization in different conditions, including dust storms, as these various conditions are likely to be encountered by Curiosity at some point. In the present work, the Nowcast of Atmospheric Ionizing Radiation for Aviation Safety model, recently modified for Mars, was used along with the Badhwar & O'Neill 2010 galactic cosmic ray model. In addition to galactic cosmic rays, five different solar energetic particle event spectra were considered. For all input radiation environments, radiation dose throughout the atmosphere and at the surface was investigated as a function of atmospheric dust loading. It is demonstrated that for galactic cosmic rays, the ionization depends strongly on the atmosphere profile. Moreover, it is shown that solar energetic particle events strongly increase the ionization throughout the atmosphere, including ground level, and can account for the radio blackout conditions observed by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument on the Mars Express spacecraft. These results demonstrate that the cosmic rays' influence on the Martian surface chemistry is strongly dependent on solar and atmospheric conditions that should be taken into account for future studies.

  10. Dust-metal Loadings and the Risk of Childhood Acute Lymphoblastic Leukemia

    PubMed Central

    Whitehead, Todd P.; Ward, Mary H.; Colt, Joanne S.; Dahl, Gary; Ducore, Jonathan; Reinier, Kyndaron; Gunier, Robert B.; Hammond, S. Katharine; Rappaport, Stephen M.; Metayer, Catherine

    2015-01-01

    We evaluated the relationship between the risk of childhood acute lymphoblastic leukemia (ALL) and levels of metals in carpet dust. A dust sample was collected from the homes of 142 ALL cases and 187 controls participating in the California Childhood Leukemia Study using a high volume small surface sampler (2001–2006). Samples were analyzed using microwave-assisted acid digestion in combination with inductively-coupled plasma mass spectrometry for arsenic, cadmium, chromium, copper, lead, nickel, tin, tungsten, and zinc. Eight metals were detected in at least 85% of the case and control homes; tungsten was detected in less than 15% of homes. Relationships between dust-metal loadings (μg metal per m2 carpet) and ALL risk were modeled using multivariable logistic regression, adjusting for the child’s age, sex, and race/ethnicity and confounders, including household annual income. A doubling of dust-metal loadings was not associated with significant changes in ALL risk [odds ratio (95% confidence interval): arsenic: 0.94 (0.83, 1.05), cadmium: 0.91 (0.80, 1.04), chromium: 0.99 (0.87, 1.12), copper: 0.96 (0.90, 1.03), lead: 1.01 (0.93, 1.10), nickel: 0.92 (0.80, 1.07), tin: 0.93 (0.82, 1.05), and zinc: 0.91 (0.81, 1.02)]. Our findings do not support the hypothesis that metals in carpet dust are risk factors for childhood ALL. PMID:25736162

  11. Dust metal loadings and the risk of childhood acute lymphoblastic leukemia.

    PubMed

    Whitehead, Todd P; Ward, Mary H; Colt, Joanne S; Dahl, Gary; Ducore, Jonathan; Reinier, Kyndaron; Gunier, Robert B; Katharine Hammond, S; Rappaport, Stephen M; Metayer, Catherine

    2015-01-01

    We evaluated the relationship between the risk of childhood acute lymphoblastic leukemia (ALL) and the levels of metals in carpet dust. A dust sample was collected from the homes of 142 ALL cases and 187 controls participating in the California Childhood Leukemia Study using a high volume small surface sampler (2001-2006). Samples were analyzed using microwave-assisted acid digestion in combination with inductively coupled plasma mass spectrometry for arsenic, cadmium, chromium, copper, lead, nickel, tin, tungsten, and zinc. Eight metals were detected in at least 85% of the case and control homes; tungsten was detected in <15% of homes. Relationships between dust metal loadings (μg metal per m(2) carpet) and ALL risk were modeled using multivariable logistic regression, adjusting for the child's age, sex, and race/ethnicity and confounders, including household annual income. A doubling of dust metal loadings was not associated with significant changes in ALL risk (odds ratio (95% confidence interval): arsenic: 0.96 (0.86, 1.07), cadmium: 0.92 (0.81, 1.05), chromium: 1.01 (0.90, 1.14), copper: 0.97 (0.91, 1.03), lead: 1.01 (0.93, 1.10), nickel: 0.95 (0.82, 1.09), tin: 0.96 (0.86, 1.08), and zinc: 0.94 (0.84, 1.05)). Our findings do not support the hypothesis that metals in carpet dust are risk factors for childhood ALL.

  12. Factors affecting lead, cadmium, and arsenic levels in house dust in a smelter town in eastern Germany

    SciTech Connect

    Meyer, I.; Heinrich, J. . Inst. fuer Epidemiologie); Lippold, U. )

    1999-07-01

    Hettstedt, a city in eastern Germany with a long history of mining and smelting of nonferrous ores, has several industrial sources of heavy metals. The indoor exposure to metals of children (5 to 14 years old) in the Hettstedt area was assessed by measuring the levels of lead, cadmium, and arsenic contamination in sedimented house dust. Factors which influence the dust loading rate and the surface loading rates of these contaminants in house dust were investigated. The geometric mean of the dust loading rate was 8.9 mg/m[sup 2] day. The geometric means of surface loading rates were 1.14, 0.024, and 0.023 [micro]g/m[sup 2] day for lead, cadmium, and arsenic, respectively. Factors that were significantly associated with surface loading rates included the city area of residence, automobile traffic near home, parent with occupational exposure to heavy metals, type of heating, housing characteristics, whether child's home is damp, number of persons living in the child's home,and parents' education. The most significant of these factors was the city area of residence, which reflects the distance from the metal sources; this factor accounted for about half of the variances explained by the regression models.

  13. Exposure of U.S. Children to Residential Dust Lead, 1999–2004: II. The Contribution of Lead-Contaminated Dust to Children’s Blood Lead Levels

    PubMed Central

    Dixon, Sherry L.; Gaitens, Joanna M.; Jacobs, David E.; Strauss, Warren; Nagaraja, Jyothi; Pivetz, Tim; Wilson, Jonathan W.; Ashley, Peter J.

    2009-01-01

    Background The U.S. Centers for Disease Control and Prevention collected health, housing, and environmental data in a single integrated national survey for the first time in the United States in 1999–2004. Objectives We aimed to determine how floor dust lead (PbD) loadings and other housing factors influence childhood blood lead (PbB) levels and lead poisoning. Methods We analyzed data from the 1999–2004 National Health and Nutrition Examination Survey (NHANES), including 2,155 children 12–60 months of age with PbB and PbD measurements. We used linear and logistic regression models to predict log-transformed PbB and the odds that PbB was ≥ 5 and ≥ 10 μg/dL at a range of floor PbD. Results The population-weighted geometric mean (GM) PbB was 2.0 μg/dL (geometric standard error = 1.0). Age of child, race/ethnicity, serum cotinine concentration, poverty-to-income ratio, country of birth, year of building construction, floor PbD by floor surface and condition, windowsill PbD, presence of deteriorated paint, home-apartment type, smoking in the home, and recent renovation were significant predictors in either the linear model [the proportion of variability in the dependent variable accounted for by the model (R2) = 40%] or logistic model for 10 μg/dL (R2 = 5%). At floor PbD = 12 μg/ft2, the models predict that 4.6% of children living in homes constructed before 1978 have PbB ≥ 10 μg/dL, 27% have PbB ≥ 5 μg/dL, and the GM PbB is 3.9 μg/dL. Conclusions Lowering the floor PbD standard below the current standard of 40 μg/ft2 would protect more children from elevated PbB. PMID:19337524

  14. Comparison of techniques to reduce residential lead dust on carpet and upholstery: the new jersey assessment of cleaning techniques trial.

    PubMed Central

    Yiin, Lih-Ming; Rhoads, George G; Rich, David Q; Zhang, Junfeng; Bai, Zhipeng; Adgate, John L; Ashley, Peter J; Lioy, Paul J

    2002-01-01

    High-efficiency particulate air (HEPA) filtered vacuum cleaners are recommended by the U.S. Department of Housing and Urban Development for cleaning lead-contaminated house dust. We performed a randomized field study to determine whether a conventional (non-HEPA) vacuum cleaner could achieve cleaning results comparable with those of a HEPA vacuum cleaner. We compared the lead loading reductions of these two vacuum cleaners in a total of 127 New Jersey homes of lead-exposed children. We used wet towelettes and a vacuum sampler to collect lead dust from carpets and upholstery before and after vacuum cleaning. The vacuum sampling data showed that the HEPA and non-HEPA vacuum cleaners resulted in 54.7% (p = 0.006) and 36.4% (p = 0.020) reductions in lead loading, respectively, when used on soiled carpets, although the overall difference in lead loading reduction between the two vacuum cleaners was not statistically significant (p = 0.293). The wipe sampling data did not show any significant lead loading reduction for either of the vacuum cleaners, suggesting that both vacuum cleaners fail to clean the surfaces of carpet effectively, considering that wipe sampling media simulate surface contact. On upholstery, the wipe sampling data showed a significant reduction in lead loading for the non-HEPA vacuum cleaner (22.2%, p = 0.047). Even with the significant reduction, the postcleaning lead loadings on upholstery were similar to those on carpets. The similar lead loading results for carpets and upholstery indicate that soiled upholstery may be as important a source of childhood lead exposure as carpets. PMID:12460803

  15. Provenance of dust to Antarctica: A lead isotopic perspective

    NASA Astrophysics Data System (ADS)

    Gili, Stefania; Gaiero, Diego M.; Goldstein, Steven L.; Chemale, Farid, Jr.; Koester, Edinei; Jweda, Jason; Vallelonga, Paul; Kaplan, Michael R.

    2016-03-01

    Antarctic ice preserves an ~800 kyr record of dust activity in the Southern Hemisphere. Major efforts have been dedicated to elucidate the origin of this material in order to gain greater insight into the atmospheric dust cycle. On the basis of Pb isotopes in Antarctic dust samples and potential sources, this contribution demonstrates for the first time that Patagonia is the main contributor of dust to Antarctica during interglacial periods as well as glacials, although the potential importance of Tierra del Fuego remains unclear because of its geochemical similarities to Patagonia. An important new finding is that the Puna-Altiplano sector of the continent is a second important dust source to eastern Antarctica during both glacials and interglacials, being more prominent during interglacials. The data indicate South America is the primary dust source to Antarctica during both glacials and interglacials.

  16. Childhood lead poisoning associated with lead dust contamination of family vehicles and child safety seats - Maine, 2008.

    PubMed

    2009-08-21

    Persons employed in high-risk lead-related occupations can transport lead dust home from a worksite through clothing, shoes, tools, or vehicles. During 2008, the Maine Childhood Lead Poisoning Prevention Program (MCLPPP) identified 55 new cases of elevated (>or=15 microg/dL) venous blood lead levels (BLLs) among children aged <6 years through mandated routine screening. Although 90% of childhood lead poisoning cases in Maine during 2003-2007 had been linked to lead hazards in the child's home, no lead-based paint or dust or water with elevated lead levels were found inside the homes associated with six of the 2008 cases (i.e., five families, including one family with two affected siblings). An expanded environmental investigation determined that these six children were exposed to lead dust in the family vehicles and in child safety seats. The sources of the lead dust were likely household contacts who worked in high-risk lead exposure occupations. Current recommendations for identifying and reducing risk from take-home lead poisoning include 1) ensuring that children with elevated BLLs are identified through targeted blood lead testing, 2) directing prevention activities to at-risk workers and employers, and 3) improving employer safety protocols. State and federal prevention programs also should consider, when appropriate, expanded environmental lead dust testing to include vehicles and child safety seats.

  17. Lead and zinc dust depositions from ore trains characterised using lead isotopic compositions.

    PubMed

    Kristensen, L J; Taylor, M P; Morrison, A L

    2015-03-01

    This study investigates an unusual source of environmental lead contamination - the emission and deposition of lead and zinc concentrates along train lines into and out of Australia's oldest silver-lead-zinc mine at Broken Hill, Australia. Transport of lead and zinc ore concentrates from the Broken Hill mines has occurred for more than 125 years, during which time the majority was moved in uncovered rail wagons. A significant amount of ore was lost to the adjoining environments, resulting in soil immediately adjacent to train lines elevated with concentrations of lead (695 mg kg(-1)) and zinc (2230 mg kg(-1)). Concentrations of lead and zinc decreased away from the train line and also with depth shown in soil profiles. Lead isotopic compositions demonstrated the soil lead contained Broken Hill ore in increasing percentages closer to the train line, with up to 97% apportioned to the mined Broken Hill ore body. SEM examination showed ceiling dusts collected from houses along the train line were composed of unweathered galena particles, characteristic of the concentrate transported in the rail wagons. The loss of ore from the uncovered wagons has significantly extended the environmental footprint of contamination from local mining operations over an area extending hundreds of kilometres along each of the three train lines.

  18. A study of urban housing demolition as a source of lead in ambient dust on sidewalks, streets, and alleys.

    PubMed

    Farfel, Mark R; Orlova, Anna O; Lees, Peter S J; Rohde, Charles; Ashley, Peter J; Julian Chisolm, J

    2005-10-01

    We examined changes in ambient dust lead (Pb) levels associated with the demolition of older row houses containing lead paint in Baltimore, MD, USA. Our previous paper describes the three study sites, the demolition processes, and increases in the Pb dustfall rate during demolition (>40-fold) and debris removal (>6-fold) within 10 m of sites where wetting was of limited effectiveness. This paper presents the analysis of settled dust collected using a cyclone device from streets, sidewalks, and alleys within 100 m of study sites before, immediately after, and 1 month after demolition. We found acute increases in Pb loadings and dust loadings after demolition and debris removal that are of public health concern. Streets and alleys had the greatest increases in Pb loadings and the highest levels overall. At one site, geometric mean (GM) Pb loadings immediately after demolition increased 200% for streets to 8080 microg/ft(2), 138% for alleys to 6020 microg/ft(2), and 26% for sidewalks to 2170 microg/ft(2). One month after demolition, the GM Pb loadings for streets, alleys, and sidewalks were reduced on average by 41-67% from post-demolition levels and were below baseline levels for alleys and sidewalks. The other main site had smaller increases in GM Pb loadings immediately after demolition-18% for alleys to 1740 microg/ft(2) and 18% for sidewalks to 2050 microg/ft(2)-and a decrease of 29% for streets to 2730 microg/ft(2). Exterior dust is a public health concern because it is a pathway of ambient Pb exposure and a potential source of residential exposure via tracking and re-aerosolization and re-deposition. Our findings highlight the need to control demolition-related Pb deposition and to educate planners, contractors, and health and housing agencies. This is particularly important given the large numbers of aging US dwellings that will be razed as part of future urban redevelopment efforts.

  19. Manganese and lead in dust fall accumulation in elementary schools near a ferromanganese alloy plant.

    PubMed

    Menezes-Filho, José Antonio; Souza, Karine O Fraga de; Rodrigues, Juliana L Gomes; Santos, Nathália Ribeiro Dos; Bandeira, Matheus de Jesus; Koin, Ng Lai; Oliveira, Sérgio S do Prado; Godoy, Ana Leonor P Campos; Mergler, Donna

    2016-07-01

    Previous studies have shown elevated airborne manganese (Mn) in villages adjacent to a Mn alloy production plant in Brazil and negative associations between biomarkers of Mn and children's cognition and behavior. Since small Mn particles may be carried for long distances, we measured manganese (Mn) and lead (Pb) dust fall accumulation in 15 elementary schools, located between 1.25 and 6.48km from the plant in the municipality of Simões Filho, Bahia, Brazil. Passive samplers (polyethylene Petri dishes) were set in interior and exterior environments. After 30 days, the samplers' content was solubilized with diluted nitric acid and Mn and Pb levels were analyzed by electrothermal absorption spectrometry. The overall geometric mean and range of Mn and Pb accumulation in dust fall (loading rates) were 1582μg Mn/m(2)/30 days (37-37,967) and 43.2μg Pb/m(2)/30 days (2.9-210.4). A logarithmic decrease in interior and exterior Mn loading rates was observed with distance from the ferro-manganese alloy plant. Multiple regression analyses of log-transformed Mn loading rate within the schools showed a positive association with Mn levels in outdoor dust, a negative association with distance from the plant; as well, wind direction (downwind>upwind) and school location (urban>rural) entered significantly into the model. For the interior school environments, located within a 2-km radius from the plant, loading rate was, on average, 190 times higher than the Mn levels reported by Gulson et al., (2014) in daycare centers in Sydney, Australia, using a similar method. Pb loading rates were not associated with distance from the plant and were lower than the rates observed in the same daycare centers in Sydney. Our findings suggest that a significant portion of the children in this town in Brazil may be exposed to airborne Mn at concentrations that may affect their neurodevelopment. Copyright © 2016 Elsevier Inc. All rights reserved.

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

    The dust is emitted from municipal solid waste incinerators (MSWIs). Volatile toxic heavy metals are abundant in smaller dust particles and influence the toxicity of particulate matter such as fine particles <2.5 μm (PM2.5). However, little is known about the properties of these metals in fine dust particles. Therefore, X-ray absorption fine structure (XAFS) spectroscopy was used to investigate the chemical states of lead (Pb), chromium (Cr), and cadmium (Cd) in MSWI dust collected for nine particle size fractions at the inlet of the dust collector and the stacks of two MSWI plants. XAFS spectroscopy of the dust in the inlet of the dust collectors showed that finer dust contained predominantly Pb as PbCl2 with some PbSiO3, coarser dust consisted of Cr forms, including more toxic Cr(VI) species, and all dust contained CdCl2. Although the dust collector removed almost all of the Pb, trace amounts of PbCl2 remained in the stack gas after passing through the dust collector.

  1. Lake Michigan sediment lead storage and history of loads

    EPA Science Inventory

    Dated sediment box cores collected in 1994-1996 from 52 locations in Lake Michigan were analyzed for to access storage, trends, and loading history of lead. The results of this study provide information of historic lead loads to the lake for a time period for which no other info...

  2. Lake Michigan sediment lead storage and history of loads

    EPA Science Inventory

    Dated sediment box cores collected in 1994-1996 from 52 locations in Lake Michigan were analyzed for to access storage, trends, and loading history of lead. The results of this study provide information of historic lead loads to the lake for a time period for which no other info...

  3. Perceptual Load Affects Eyewitness Accuracy and Susceptibility to Leading Questions

    PubMed Central

    Murphy, Gillian; Greene, Ciara M.

    2016-01-01

    Load Theory (Lavie, 1995, 2005) states that the level of perceptual load in a task (i.e., the amount of information involved in processing task-relevant stimuli) determines the efficiency of selective attention. There is evidence that perceptual load affects distractor processing, with increased inattentional blindness under high load. Given that high load can result in individuals failing to report seeing obvious objects, it is conceivable that load may also impair memory for the scene. The current study is the first to assess the effect of perceptual load on eyewitness memory. Across three experiments (two video-based and one in a driving simulator), the effect of perceptual load on eyewitness memory was assessed. The results showed that eyewitnesses were less accurate under high load, in particular for peripheral details. For example, memory for the central character in the video was not affected by load but memory for a witness who passed by the window at the edge of the scene was significantly worse under high load. High load memories were also more open to suggestion, showing increased susceptibility to leading questions. High visual perceptual load also affected recall for auditory information, illustrating a possible cross-modal perceptual load effect on memory accuracy. These results have implications for eyewitness memory researchers and forensic professionals. PMID:27625628

  4. Perceptual Load Affects Eyewitness Accuracy and Susceptibility to Leading Questions.

    PubMed

    Murphy, Gillian; Greene, Ciara M

    2016-01-01

    Load Theory (Lavie, 1995, 2005) states that the level of perceptual load in a task (i.e., the amount of information involved in processing task-relevant stimuli) determines the efficiency of selective attention. There is evidence that perceptual load affects distractor processing, with increased inattentional blindness under high load. Given that high load can result in individuals failing to report seeing obvious objects, it is conceivable that load may also impair memory for the scene. The current study is the first to assess the effect of perceptual load on eyewitness memory. Across three experiments (two video-based and one in a driving simulator), the effect of perceptual load on eyewitness memory was assessed. The results showed that eyewitnesses were less accurate under high load, in particular for peripheral details. For example, memory for the central character in the video was not affected by load but memory for a witness who passed by the window at the edge of the scene was significantly worse under high load. High load memories were also more open to suggestion, showing increased susceptibility to leading questions. High visual perceptual load also affected recall for auditory information, illustrating a possible cross-modal perceptual load effect on memory accuracy. These results have implications for eyewitness memory researchers and forensic professionals.

  5. Surface dust wipes are the best predictors of blood leads in young children with elevated blood lead levels

    SciTech Connect

    Gulson, Brian; Anderson, Phil; Taylor, Alan

    2013-10-15

    Background: As part of the only national survey of lead in Australian children, which was undertaken in 1996, lead isotopic and lead concentration measurements were obtained from children from 24 dwellings whose blood lead levels were ≥15 µg/dL in an attempt to determine the source(s) of their elevated blood lead. Comparisons were made with data for six children with lower blood lead levels (<10 µg/dL). Methods: Thermal ionisation and isotope dilution mass spectrometry were used to determine high precision lead isotopic ratios ({sup 208}Pb/{sup 206}Pb, {sup 207}Pb/{sup 206}Pb and {sup 206}Pb/{sup 204}Pb) and lead concentrations in blood, dust from floor wipes, soil, drinking water and paint (where available). Evaluation of associations between blood and the environmental samples was based on the analysis of individual cases, and Pearson correlations and multiple regression analyses based on the whole dataset. Results and discussion: The correlations showed an association for isotopic ratios in blood and wipes (r=0.52, 95% CI 0.19–0.74), blood and soil (r=0.33, 95% CI −0.05–0.62), and blood and paint (r=0.56, 95% CI 0.09–0.83). The regression analyses indicated that the only statistically significant relationship for blood isotopic ratios was with dust wipes (B=0.65, 95% CI 0.35–0.95); there were no significant associations for lead concentrations in blood and environmental samples. There is a strong isotopic correlation of soils and house dust (r=0.53, 95% CI 0.20–0.75) indicative of a common source(s) for lead in soil and house dust. In contrast, as with the regression analyses, no such association is present for bulk lead concentrations (r=−0.003, 95% CI −0.37–0.36), the most common approach employed in source investigations. In evaluation of the isotopic results on a case by case basis, the strongest associations were for dust wipes and blood. -- Highlights: • Children with elevated blood lead ≥15 µg/dL compared with a group with <10

  6. Lead and other heavy metals in dust fall from single-family housing demolition.

    PubMed

    Jacobs, David E; Cali, Salvatore; Welch, Alison; Catalin, Bogdan; Dixon, Sherry L; Evens, Anne; Mucha, Amy P; Vahl, Nicole; Erdal, Serap; Bartlett, John

    2013-01-01

    We measured lead and other heavy metals in dust during older housing demolition and effectiveness of dust suppression. We used American Public Housing Association Method 502 and U.S. Environmental Protection Agency Methods SW3050B and SW6020 at 97 single-family housing demolition events with intermittent (or no) use of water to suppress dust at perimeter, non-perimeter, and locations without demolition, with nested mixed modeling and tobit modeling with left censoring. The geometric mean (GM) lead dust fall during demolition was 6.01 micrograms of lead per square foot per hour (μg Pb/ft(2)/hour). GM lead dust fall was 14.18 μg Pb/ft(2)/hour without dust suppression, but declined to 5.48 μg Pb/ft(2)/hour (p=0.057) when buildings and debris were wetted. Significant predictors included distance, wind direction, and main street location. At 400 feet, lead dust fall was not significantly different from background. GM lead concentration at demolition (2,406 parts per million [ppm]) was significantly greater than background (GM=579 ppm, p=0.05). Arsenic, chromium, copper, iron, and manganese demolition dust fall was significantly higher than background (p<0.001). Demolition of approximately 400 old housing units elsewhere with more dust suppression was only 0.25 μg Pb/ft(2)/hour. Lead dust suppression is feasible and important in single-family housing demolition where distances between houses are smaller and community exposures are higher. Neighbor notification should be expanded to at least 400 feet away from single-family housing demolition, not just adjacent properties. Further research is needed on effects of distance, potential water contamination, occupational exposures, and water application.

  7. Lead and Other Heavy Metals in Dust Fall from Single-Family Housing Demolition

    PubMed Central

    Cali, Salvatore; Welch, Alison; Catalin, Bogdan; Dixon, Sherry L.; Evens, Anne; Mucha, Amy P.; Vahl, Nicole; Erdal, Serap; Bartlett, John

    2013-01-01

    Objective We measured lead and other heavy metals in dust during older housing demolition and effectiveness of dust suppression. Methods We used American Public Housing Association Method 502 and U.S. Environmental Protection Agency Methods SW3050B and SW6020 at 97 single-family housing demolition events with intermittent (or no) use of water to suppress dust at perimeter, non-perimeter, and locations without demolition, with nested mixed modeling and tobit modeling with left censoring. Results The geometric mean (GM) lead dust fall during demolition was 6.01 micrograms of lead per square foot per hour (μg Pb/ft2/hour). GM lead dust fall was 14.18 μg Pb/ft2/hour without dust suppression, but declined to 5.48 μg Pb/ft2/hour (p=0.057) when buildings and debris were wetted. Significant predictors included distance, wind direction, and main street location. At 400 feet, lead dust fall was not significantly different from background. GM lead concentration at demolition (2,406 parts per million [ppm]) was significantly greater than background (GM=579 ppm, p=0.05). Arsenic, chromium, copper, iron, and manganese demolition dust fall was significantly higher than background (p<0.001). Demolition of approximately 400 old housing units elsewhere with more dust suppression was only 0.25 μg Pb/ft2/hour. Conclusions Lead dust suppression is feasible and important in single-family housing demolition where distances between houses are smaller and community exposures are higher. Neighbor notification should be expanded to at least 400 feet away from single-family housing demolition, not just adjacent properties. Further research is needed on effects of distance, potential water contamination, occupational exposures, and water application. PMID:24179257

  8. Canadian House Dust Study: Lead Bioaccessibility and Speciation

    SciTech Connect

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

    2011-12-31

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

  9. Volcanic Loading: The Dust Veil Index (1985) (NDP-013)

    DOE Data Explorer

    Lamb, H. H. [University of East Anglia, Norwich, United Kingdom; Boden, Thomas A. [CDIAC, Oak Ridge National Laboratory; Watts, Julia A. [Oak Ridge National Laboratory

    1985-09-01

    Lamb's Dust Veil Index (DVI) is a numerical index that quantifies the impact of a particular volcanic eruption's release of dust and aerosols over the years following the event, especially the impact on the Earth's energy balance. DVIs have been calculated for eruptions occurring from 1500 through 1983. The methods used to calculate the DVI have been intercalibrated to give a DVI of 1000 for the eruption of Krakatoa in 1883. The DVI for any volcanic eruption is based on a review of the observational, empirical, and theoretical studies of the possible impact on climate of volcanic dust veils. The DVI allows one to compare volcanic eruptions by a single numerical index. The data base includes the name of the erupting volcano, year of eruption, volcano latitude and longitude, maximum extent of the dust veil, veil duration, DVI for the entire globe, DVI for the Northern Hemisphere, and DVI for the Southern Hemisphere. The data are in one file (22.6 kB).

  10. Simulation of the Radiative Impact of High Dust Loading during a Dust Storm in March 2012

    NASA Astrophysics Data System (ADS)

    Puthan Purakkal, J.; Kalenderski, S.; Stenchikov, G. L.

    2013-12-01

    We investigated a severe dust storm that developed over vast areas of the Middle East on 18-19 March 2012 and affected Saudi Arabia, Sudan, Egypt, Jordan, United Arab Emirates, Bahrain, Qatar, Oman, Kuwait, Iraq, Iran, Israel, and Pakistan. The visible aerosol optical depth recorded by the AERONET station on the KAUST campus (22.30o N 39.10o E) during the storm reached 4.5, exceeding the average level by an order of magnitude. To quantify the effects of the dust on atmospheric radiation and dynamics, we analyzed available ground-based and satellite observations and conducted numerical simulations using a fully coupled meteorology-chemistry-aerosol model (WRF-Chem). The model was able to reproduce the spatial and temporal patterns of the aerosol optical depths (AOD) observed by airborne and ground-based instruments. The major dust sources included river valleys of lower Tigris and Euphrates in Iraq, desert areas in Kuwait, Iran, United Arab Emirates, central Arabia including Rub' al Khali, An Nafud, and Ad Dahna, as well as the Red Sea coast of the Arabian Peninsula. The total amount of dust generated across the entire domain during the period of the simulation reached 93.76 Mt; 73.04 Mt of dust was deposited within the domain; 6.56 Mt of dust sunk in the adjacent sea waters, including 1.20 Mt that sedimented into the Red Sea. The model predicted a well-mixed boundary layer expanding up to 3.5 km in the afternoon. Some dust plumes were seen above the Planetary Boundary layer. In our simulations, mineral dust heated the lower atmosphere with a maximum heating rate of 9 K/day. The dust storm reduced the downwelling shortwave radiation at the surface to a maximum daily average value of -134 Wm-2 and the daily averaged long-wave forcing at the surface increased to 43 Wm-2. The combined short-wave cooling and long-wave warming effects of dust aerosols caused significant reduction in the surface air temperature -6.7 K at 1200 UTC on 19 March 2013.

  11. How to minimize iron loss while decontaminating converter dust from lead.

    PubMed

    Moussavi, Mohsen; Fathikalajahi, Jamshid; Khalili, Fariba

    2011-12-01

    The purpose of this work was to decontaminate a converter flue dust from lead while minimizing the iron loss from the dust matrix. A physicochemical method based on a leaching cascade was applied to remove lead impurities with HCl. Finally, the lead-rich wastes generated at the end of the operations were further treated in order to meet the standards of waste disposal sites. The results show that lead could be removed from the dust with efficiencies of better than 90%. However, some iron was lost in these operations. It was noticed that under optimum conditions 8.5 g of iron would be lost as leachate per each gram of removed lead. It was also noticed that the lead-treated dust was more concentrated in iron and had less calcium. A number of parameters that could affect the amount of iron loss, such as acid dose, exposure time and temperature, were identified and the extent of the effects are presented. It was concluded that the lead content in the flue dust could practically be lowered to any level. It was also concluded that the difference between the solubility of lead chloride in cold and hot water, as well as the affinity of certain ligands such as Cl- and OH- to form stable complexes with lead ions, played a key role in this study. The lead-containing complexes in the leachate were identified to be predominantly PbCl3- and PbCl+.

  12. Estimation of Collection Efficiency Change of Moving Granular Bed Filter by Dust Load

    SciTech Connect

    Furuuchi, M.; Hata, M.; Kanaoka, C.; Kawaminami, Y.

    2002-09-18

    Final goal of this study is to theoretically describe effects of influencing factors on the performance of the coke bed filter as a material classifier and to predict its optimal operating condition. In this paper, the author focuses on the basic investigation on collection mechanism of a fixed coke bed filter on the basis of the depth filtration theory, in which an influence of dust load on the dust collection efficiency.

  13. Effect of atmospheric dust loading on martian albedo measurements

    NASA Astrophysics Data System (ADS)

    Zinzi, Angelo; Palomba, Ernesto; Rinaldi, Giovanna; D'Amore, Mario

    2010-08-01

    This work is devoted to the analysis of the variation of albedo measured by orbiting instruments with atmospheric opacity on Mars. The study has been conduced by analysing Mars Global Surveyor Thermal Emission Spectrometer (MGS-TES) data from martian regions with different surface albedo. In support of these data, synthetic spectra with different surface albedo and atmospheric opacities have been computed, so that a comparison has been performed. The synthetic spectra have been retrieved by using two different grain sizes for suspended dust (0.5 and 1.2 μm), allowing a comparison between the two models and the observations. Using the DCI, a parameter describing the quantity of dust deposited on the surface, the effectiveness of the single scattering approximation has been tested for low atmospheric opacity by analysing the quality of the linear fit up to different atmospheric opacity. For more opaque conditions two kinds of fits have been applied to the data, linear and second-order degree polynomial. In this case, we found that the polynomial fit better describes the observations. The analysis of these data made it possible to notice a peculiar trend, already reported by Christensen (1988), of the albedo over Syrtis Major after the occurrence of dust storms, but, differently from that work, now the study of DCI together with atmospheric opacity and albedo allowed us to robustly confirm the hypothesis made by Christensen. Finally, the comparison between observations and synthetic spectra computed with models with different particles grain sizes indicates that dust particles of 0.5 μm diameter are the most effective to change the aerosol atmospheric opacity on Mars.

  14. Lead (Pb) in old Antarctic ice: Some from dust, some from other sources

    USGS Publications Warehouse

    Hinkley, T.

    2007-01-01

    Recently published data on amounts and isotopic compositions of lead (Pb) and on amounts of mineral dust in pre-industrial Antarctic ice can be further interpreted by means of simple calculations. These show that two distinct types of Pb were provided by the atmosphere to the continent in varying proportions during Pleistocene and Holocene time. One type of Pb is that contained in the mineral lattices of dust. It has non-radiogenic isotopic proportions. The other type of Pb is not associated with dust minerals, is more radiogenic, and is consistent with an origin in emissions from ocean island volcanoes worldwide, or from some Antarctic volcanoes.

  15. Impact of traffic intensity and pavement aggregate size on road dust particles loading

    NASA Astrophysics Data System (ADS)

    Amato, F.; Pandolfi, M.; Alastuey, A.; Lozano, A.; Contreras González, J.; Querol, X.

    2013-10-01

    Road dust emissions severely hamper PM10 urban air quality and their burden is expected to increase relatively to primary motor exhaust emissions. Beside the large influence of climate and meteorology, the emission potential varies widely also from one road to another due to numerous factors such as traffic conditions, pavement type and external sources. Nevertheless none of these factors is sufficiently known for a reliable description in emission modelling and for decision making in air quality management. In this study we carried out intensive road dust measurement campaigns in South Spain, with the aim of investigating the relationship between emission potential (i.e. road dust load) and traffic intensity, pavement aggregate size and distance from braking zones. Results indicate that, while no impact from braking activity can be drawn on the bulk road dust mass, an increase in traffic intensity or mean pavement aggregate size clearly reduce the single vehicle emission potential.

  16. Linkages between observed, modeled Saharan dust loading and meningitis in Senegal during 2012 and 2013

    NASA Astrophysics Data System (ADS)

    Diokhane, Aminata Mbow; Jenkins, Gregory S.; Manga, Noel; Drame, Mamadou S.; Mbodji, Boubacar

    2016-04-01

    The Sahara desert transports large quantities of dust over the Sahelian region during the Northern Hemisphere winter and spring seasons (December-April). In episodic events, high dust concentrations are found at the surface, negatively impacting respiratory health. Bacterial meningitis in particular is known to affect populations that live in the Sahelian zones, which is otherwise known as the meningitis belt. During the winter and spring of 2012, suspected meningitis cases (SMCs) were with three times higher than in 2013. We show higher surface particular matter concentrations at Dakar, Senegal and elevated atmospheric dust loading in Senegal for the period of 1 January-31 May during 2012 relative to 2013. We analyze simulated particulate matter over Senegal from the Weather Research and Forecasting (WRF) model during 2012 and 2013. The results show higher simulated dust concentrations during the winter season of 2012 for Senegal. The WRF model correctly captures the large dust events from 1 January-31 March but has shown less skill during April and May for simulated dust concentrations. The results also show that the boundary conditions are the key feature for correctly simulating large dust events and initial conditions are less important.

  17. Linkages between observed, modeled Saharan dust loading and meningitis in Senegal during 2012 and 2013.

    PubMed

    Diokhane, Aminata Mbow; Jenkins, Gregory S; Manga, Noel; Drame, Mamadou S; Mbodji, Boubacar

    2016-04-01

    The Sahara desert transports large quantities of dust over the Sahelian region during the Northern Hemisphere winter and spring seasons (December-April). In episodic events, high dust concentrations are found at the surface, negatively impacting respiratory health. Bacterial meningitis in particular is known to affect populations that live in the Sahelian zones, which is otherwise known as the meningitis belt. During the winter and spring of 2012, suspected meningitis cases (SMCs) were with three times higher than in 2013. We show higher surface particular matter concentrations at Dakar, Senegal and elevated atmospheric dust loading in Senegal for the period of 1 January-31 May during 2012 relative to 2013. We analyze simulated particulate matter over Senegal from the Weather Research and Forecasting (WRF) model during 2012 and 2013. The results show higher simulated dust concentrations during the winter season of 2012 for Senegal. The WRF model correctly captures the large dust events from 1 January-31 March but has shown less skill during April and May for simulated dust concentrations. The results also show that the boundary conditions are the key feature for correctly simulating large dust events and initial conditions are less important.

  18. [Road dust loading and chemical composition at major cities in Fujian Province].

    PubMed

    Zheng, An; Yang, Bing-yu; Wu, Shui-ping; Wang, Xin-hong; Chen, Xiao-qiu

    2013-05-01

    A total of 57 road dust and 16 urban soil samples were collected from four cities, Xiamen, Zhangzhou, Quanzhou and Putian in Fujian Province, China. Twenty-six elements, eight water soluble ions, organic carbon and elemental carbon in the fraction of particulate diameter less than 2.5 microm (PM2.5) derived through a suspension chamber were analyzed. The average loading of road dust with diameter less than 100 microm in the four cities ranged from 6.99 g x m(-2) to 10.11 g x m(-2), while the loading of PM2.5 ranged from 4.0 mg x m(-2) to 12.5 mg x m(-2). Both the soil and road dust samples were characterized with much higher concentrations of Si, Ca, Al, Fe and K. But for the anthropogenic elements such as Cu, Pb, Zn,Cr and Ti, much lower levels were found in the soil PM2.5, than those in the road dust PM2.5. Significantly higher levels of NH4+, NO3- and SO4(2-) were found in the road dust PM2.5 from Zhangzhou in comparison with those from other cities in this study. The calcium ion (Ca2+) content was significantly positively correlated with the Mg2+ content in the road dust PM2.5 from Xiamen, Zhangzhou and Quanzhou. The levels of organic carbon (OC) in the road dust PM2.5 in these four cities were higher than those reported in Ji'nan, Shijiazhuang and Beijing while the levels of elemental carbon (EC) were all lower than those in the urban road dust from Beijing, Significant positive correlation between EC and OC was found in samples from Quanzhou and Putian, suggesting the same and/or similar sources. The result of mass balance indicated that higher percentage compositions were soil and OM in both Quanzhou and Putian. Based on the cluster analysis, the 57 road dust samples were divided into four types: influenced by atmospheric deposition, influenced by soil dust, influenced by atmospheric deposition and soil dust, and influenced by soil and construction dust.

  19. Dust-mediated loading of trace and major elements to Wasatch Mountain snowpack.

    PubMed

    Carling, Gregory T; Fernandez, Diego P; Johnson, William P

    2012-08-15

    Depth-integrated snow columns were collected at 12 sites across the central Wasatch Mountains, Utah, during March and April 2010 to determine concentrations of trace elements, major anions and cations, and pH. Sample collection was conducted at or near maximum snow accumulation prior to the onset of melt, and included spring dust events driven by southerly pre-frontal winds. Snow samples were melted in the laboratory and subsampled for analyses on filtered (0.45 μm) and unfiltered fractions. All measured elements (Al, As, Ba, Ca, Co, Cr, Cu, Fe, Hg, K, Li, Mg, Mn, Na, Ni, Pb, Sb, Sr, Ti, Tl, U, V, and Zn) and major anions (Cl, NO(3), and SO(4)) displayed significant increases in concentration (for example, factor of 2 to 5 increases for As, Cr, Hg, and Pb) between the six sites sampled in March (prior to dust events) and the six sites sampled in April (after dust events). Acid neutralizing capacity and pH were also elevated in April relative to March snowpack. Comparison of elemental concentration in the particulate (>0.45 μm; difference between unfiltered and filtered concentration) and soluble (<0.45 μm; filtered concentration) fractions shows that the concentration increase between March and April snowpack for the trace elements is primarily a result of association with dust particles >0.45 μm. The results suggest that the majority of trace element loading to the Wasatch snowpack occurs via dust deposition. The major elements were primarily loaded in the <0.45 μm fraction, suggesting deposition of soluble dust particles. The overall findings of this paper are similar to other studies regarding the role of dust on nutrient and trace element accumulation in soils and lake sediments, but to our knowledge this is the first study that compares trace element chemistry of seasonal snowpack before and after dust deposition events.

  20. EFFECT OF LOADING DUST TYPE ON THE FILTRATION EFFICIENCY OF ELECTROSTATICALLY CHARGED FILTERS

    EPA Science Inventory

    The paper gives results of an evaluation of the effect of loading dust type on the filtration efficiency of electrostatically charged filters. Three types of filters were evaluated: a rigid-cell filter charged using an electrodynamic spinning process, a pleated-panel filter cha...

  1. EFFECT OF LOADING DUST TYPE ON THE FILTRATION EFFICIENCY OF ELECTROSTATICALLY CHARGED FILTERS

    EPA Science Inventory

    The paper gives results of an evaluation of the effect of loading dust type on the filtration efficiency of electrostatically charged filters. Three types of filters were evaluated: a rigid-cell filter charged using an electrodynamic spinning process, a pleated-panel filter cha...

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

    SciTech Connect

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

    2002-07-23

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

  3. Surface dust wipes are the best predictors of blood leads in young children with elevated blood lead levels.

    PubMed

    Gulson, Brian; Anderson, Phil; Taylor, Alan

    2013-10-01

    As part of the only national survey of lead in Australian children, which was undertaken in 1996, lead isotopic and lead concentration measurements were obtained from children from 24 dwellings whose blood lead levels were ≥15 µg/dL in an attempt to determine the source(s) of their elevated blood lead. Comparisons were made with data for six children with lower blood lead levels (<10 µg/dL). Thermal ionisation and isotope dilution mass spectrometry were used to determine high precision lead isotopic ratios (208Pb/206pb, 207Pb/206Pb and 206Pb/204Pb) and lead concentrations in blood, dust from floor wipes, soil, drinking water and paint (where available). Evaluation of associations between blood and the environmental samples was based on the analysis of individual cases, and Pearson correlations and multiple regression analyses based on the whole dataset. The correlations showed an association for isotopic ratios in blood and wipes (r=0.52, 95% CI 0.19-0.74), blood and soil (r=0.33, 95% CI -0.05-0.62), and blood and paint (r=0.56, 95% CI 0.09-0.83). The regression analyses indicated that the only statistically significant relationship for blood isotopic ratios was with dust wipes (B=0.65, 95% CI 0.35-0.95); there were no significant associations for lead concentrations in blood and environmental samples. There is a strong isotopic correlation of soils and house dust (r=0.53, 95% CI 0.20-0.75) indicative of a common source(s) for lead in soil and house dust. In contrast, as with the regression analyses, no such association is present for bulk lead concentrations (r=-0.003, 95% CI -0.37-0.36), the most common approach employed in source investigations. In evaluation of the isotopic results on a case by case basis, the strongest associations were for dust wipes and blood. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.

  4. Persistent Organic Pollutants in Dust From Older Homes: Learning From Lead

    PubMed Central

    Metayer, Catherine; Ward, Mary H.; Colt, Joanne S.; Gunier, Robert B.; Deziel, Nicole C.; Rappaport, Stephen M.; Buffler, Patricia A.

    2014-01-01

    Objectives. We aimed to (1) evaluate the relation between home age and concentrations of multiple chemical contaminants in settled dust and (2) discuss the feasibility of using lead hazard controls to reduce children’s exposure to persistent organic pollutants. Methods. As part of the California Childhood Leukemia Study, from 2001 to 2007, we used a high-volume small surface sampler and household vacuum cleaners to collect dust samples from 583 homes and analyzed the samples for 94 chemicals with gas chromatography–mass spectrometry and inductively coupled plasma mass spectrometry. We evaluated relations between chemical concentrations in dust and home age with Spearman rank correlation coefficients. Results. Dust concentrations of lead, polychlorinated biphenyls, organochlorine insecticides, and polycyclic aromatic hydrocarbons were correlated with home age (ρ > 0.2; P < .001), whereas concentrations of pyrethroid insecticides and polybrominated diphenyl ethers were not. Conclusions. Dust in older homes contains higher levels of multiple, persistent chemicals than does dust in newer homes. Further development of strategies to reduce chemical exposures for children living in older homes is warranted. PMID:24832145

  5. Tracing geogenic and anthropogenic sources in urban dusts: Insights from lead isotopes

    NASA Astrophysics Data System (ADS)

    Del Rio-Salas, R.; Ruiz, J.; De la O-Villanueva, M.; Valencia-Moreno, M.; Moreno-Rodríguez, V.; Gómez-Alvarez, A.; Grijalva, T.; Mendivil, H.; Paz-Moreno, F.; Meza-Figueroa, D.

    2012-12-01

    Tracing the source of metals in the environment is critical to understanding their pollution level and fate. Geologic materials are an important source of airborne particulate matter, but the contribution of contaminated soil to concentrations of Pb in airborne dust is not yet widely documented. To examine the potential significance of this mechanism, surface soil samples were collected, as well as wind-transported dust trapped at 1 and 2 m height at seven different locations including residential, industrial, high-traffic and rural sites. Samples of dust deposited on roofs from 24 schools were also obtained and analyzed for Pb isotope ratios. Spatial distribution of Pb of airborne and sedimented dust suggests a process dominated by re-suspension/sedimentation, which was controlled by erosion, traffic and topography of the urban area. Anthropogenic lead input in the city grades outward the urban zone toward geogenic values. Our results shows that Pb-isotopic signatures of leaded gasoline are imprinted in dust sedimented on roofs. Considering that leaded-gasoline has not been in use in Mexico since two decades ago, this signature shows not only a Pb-legacy in soil, but also a re-suspension process affecting air column below 3 m in height. The combination of the 207Pb/206Pb data of the surrounding rocks and urban dust, reveal three well-defined zones with remarkable anthropogenic influence, which correspond to the oldest urban sectors. This work highlights the importance of spatial characterization of metals in particles suspended below a height of 3 m of the airborne column, a fact that should be considered to identify exposure paths to humans and the potential risks. Lead isotope signatures allowed the identification of geogenic and anthropogenic emission sources for dust, a matter that deserves consideration in the efforts to control airborne metal emissions.

  6. Tracing dust transport from Middle-East over Delhi in March 2012 using metal and lead isotope composition

    NASA Astrophysics Data System (ADS)

    Kumar, S.; Aggarwal, S. G.; Malherbe, J.; Barre, J. P. G.; Berail, S.; Gupta, P. K.; Donard, O. F. X.

    2016-05-01

    A severe dust-storm which was originated in Middle-East crossed over Delhi during March 20-22, 2012. We have collected these dust-storm (DS) aerosol samples, and analyzed them for selected metals (As, Cd, Cr, Cu, Fe, Ni, Pb, Sb, Se, Sn, Sr, V and Zn) together with after dust-storm (ADS) and winter (WS) samples. High aerosol mass loadings were observed in DS samples (1097-1965 μg/m3). On the contrary, metals derived prominently from the anthropogenic sources were found lower in concentration compared to that of ADS and WS aerosols. We observed significantly high concentrations of Ni and V (which are abundantly found in crude oils of Middle-East origin) in the DS samples than that of ADS and WS samples. Also enrichment factor (EF) of these metals with respect to Fe shows no significant enrichment (<10). Fe (and Sr) concentrations were also 3-5 fold higher in DS samples compared to ADS and WS. These results suggest that Ni and V can be used as tracers for dust aerosols transported from Middle-East region. Lead isotope signatures can tell about the variation in the sources of urban aerosols. Therefore Pb isotope analyses of these samples were performed using MC-ICP-MS. The isotope ratios, 208Pb/206Pb is determined to be (mean ± sd) 2.1315 ± 0.0018, 2.1370 ± 0.0022 and 2.1389 ± 0.0016, whereas 206Pb/207Pb is 1.1311 ± 0.0022, 1.1244 ± 0.0017 and 1.1233 ± 0.0016 in DS, ADS and WS aerosols, respectively. There is a clear distinction in Pb isotope composition between DS and urban (ADS and WS) aerosols. Further, these results suggest that in urban aerosols, Pb is less radiogenic in nature compared to that of in transported dust aerosols collected in New Delhi.

  7. Recovery of Zinc and Lead from Electric-Furnace Steelmaking Dust at Berzelius

    NASA Astrophysics Data System (ADS)

    Maczek, Helmut; Kola, Rolf

    1980-01-01

    The Waelz unit at the Berzelius Metallhütten GmbH plant in Duisburg, West Germany, was originally built to recover zinc and lead values in zinc retort residues and slags from lead shaft furnaces. The process has also proved suitable for recovering zinc and lead from steelmaking dusts. The metallurgical characteristics and information on operating costs encountered in the three decades over which this Waelz plant has been in operation at Berzelius are described and discussed.

  8. Relative exposure of children to lead from dust and drinking water.

    PubMed

    Alexander, L M; Heaven, A; Delves, H T; Moreton, J; Trenouth, M J

    1993-01-01

    The Blackpool, Wyre and Fylde Health Authority, in the North West of England, could be described as a "low-level lead exposure area." Primary sources of lead exposure are atmospheric fallout (both indoors and outdoors) and potable water consumption. Deciduous teeth were collected from children living in this area as were water samples and outdoor dust samples. Both total lead concentrations and 206Pb:207Pb ratios were determined for a defined subset of teeth. Significant differences in the total lead concentrations were found for teeth collected from children resident in different targeted areas (i.e., Blackpool, Fleetwood, and Garstang). No significant differences were found between the total lead concentrations or the 206Pb:207Pb ratios from dust and water samples in these areas. Examination of the 206Pb:207Pb ratios for dust, water, and teeth obtained from each area separately revealed differing patterns of exposure to lead. Determination of 206Pb:207Pb ratios, in addition to total lead concentrations, enabled the differences in sources of exposure to be identified in these communities. The authors conclude that isotopic analyses are an important aspect of community survey work, and these analyses can be helpful in accurately targeting intervention strategies aimed at reducing exposure to lead.

  9. [Influence of dust load on oxidant activity and antioxidant defense parameters of workers in steel factories].

    PubMed

    Zemlianova, M A; Zaĭtseva, N V; Zvezdin, N V; Shliapnikov, D M

    2013-01-01

    The article covers data on levels of oxidative and antioxidant processes under influence of low fibrogenous dust in workers at steel mills. Reliable differences were seen between groups of workers with different dust load, dust particles size in blood, acitvity level of lipid peroxidation products occurrence--that worsens inflammatory reaction and dysfunction of lower respiratory tract. Findings are that occupations--preparation of steelpouring mixtures, converter melters, batchers--with highest silicon content of blood, if compared to other occupations and to the reference group (1.6 and 2.9 times respectively), demonstrated more intense change in parameters of oxidation processes activation (increased level of lipid hydroperoxide and malonic dialdehyde) with depressed antioxidant defense (lower level of general antioxidant defense).

  10. Sensitivity of dust emissions to aerosol feedback and the impact of dust loading on climate forcing with varied resolutions using FIM-Chem

    NASA Astrophysics Data System (ADS)

    Zhang, Li; Grell, Georg; Henze, Daven; Mckeen, Stuart; Sun, Shan; Li, Haiqin

    2016-04-01

    Meteorological conditions directly impact aerosol loading, especially dust emissions. Variations in dust emissions on the other hand, will also impact meteorology and climate through direct and indirect aerosol forcing. To study these impacts in more detail we use the global Flow-following finite-volume Icosahedra Model (FIM, http://fim.noaa.gov/), a new global weather prediction model currently under development in the Global Systems Division of NOAA/ESRL, as it is coupled online with the aerosol modules from the Goddard Gobal Ozone Chemistry Aerosol Radiation and Transport (GOCART) model (FIM-Chem). FIM-Chem includes direct and semi direct feedback, and uses the dust schemes of GOCART and the Air Force Weather Agency (AFWA). FIM-Chem is able to investigate the contribution of climate feedbacks to simulated hyperspectral data by considering a range of simulations with different dust emissions and different levels of aerosol feedbacks enabled at four different spatial resolutions. The emitted dust flux and total emissions are highly depending on the wind, soil moisture and model resolution. We compare the dust emissions by including and excluding the aerosol radiative feedback in the simulations to quantify the sensitivity of dust emissions to aerosol feedback. The results show that all aerosol-induced dust emissions increase about 10% globally, which is mainly dominated by the contributions of anthropogenic black carbon (EC) aerosol. While the dust-induced percentage changes of dust emissions are about -5.5%, that indicates reduction effect globally. Also, the simulations based on different resolutions of 240x240 km, 120x120 km, 60x60 km and 30x30 km are performed to test the impacts of model resolution on total dust emissions. By comparing the dust emission sensitivity to aerosol feedback and model resolution, we can estimate the uncertainty of model resolution versus aerosol feedback. We also conduct FIM-Chem simulations to investigate the sensitivity of dust

  11. Mineral dust transport to the Sierra Nevada, California: Loading rates and potential source areas

    NASA Astrophysics Data System (ADS)

    Vicars, William C.; Sickman, James O.

    2011-03-01

    The transport and deposition of aeolian dust represents an important material input pathway for many marine and terrestrial ecosystems and may be an ecologically significant source of exogenous phosphorus (P) to alpine lakes. In order to assess the abundance and elemental composition of atmospheric mineral dust over the Sierra Nevada of California, we collected size-fractionated atmospheric particulate matter (PM) samples during July 2008 to March 2009 at a mixed conifer site located in Sequoia National Park. PM concentrations were at their highest levels during the dry season, averaging 8.8 ± 3.7 and 11.1 ± 7.5 μg m-3 for the coarse (1 μm < Da < 15 μm) and fine (Da < 1 μm) fractions, respectively, while winter months were characterized by low (<1 μg m-3) PM concentrations in both size fractions. Using Al as a diagnostic tracer for mineral aerosol, we observed a significant and uniform contribution (50-80%) from aeolian dust to the total coarse PM load, whereas submicron particles contained comparatively little crustal material (7-33%). The mass concentrations of elements (Fe, Ca, Mg, P, and V) in the coarse PM fraction were significantly correlated with Al throughout the study, and coarse PM exhibited elemental signatures that were temporally consistent and distinguishable from those of other sites. Conversely, higher elemental enrichments were observed in the fine PM fraction for Fe, V, and P, indicating a greater contribution from anthropogenic emissions to the fine particle load. Fe/Al and Fe/Ca ratios suggest a mixture of mineral dust from regional agricultural activities and long-range transport of mineral dust from Asia. Asian sources comprised 40-90% of mineral dust in July 2008 and then declined to between 10 and 30% in August and early September.

  12. 42 CFR 84.1146 - Lead fume test for dust, fume, and mist respirators; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Lead fume test for dust, fume, and mist respirators; minimum requirements. 84.1146 Section 84.1146 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL...

  13. The bioaccessibility of lead (Pb) from vacuumed house dust on carpets in urban residences.

    PubMed

    Yu, Chang Ho; Yiin, Lih-Ming; Lioy, Paul J

    2006-02-01

    Risk assessments for toxicants in environmental media via oral exposure often rely on measurements of total concentration in a collected sample. However, the human digestive system cannot dissolute all of a toxicant present in the binding matrix, and cannot absorb it with nearly 100% efficiency. In vitro bioaccessibility has been developed as a method to estimate oral bioavailability of a toxicant using a physiologically-based extraction procedure. Bioaccessibility measurements are more physiologically relevant than strong acid leaching measurements of concentration. A method for measuring bioaccessible lead in house dust was derived from the bioaccessibility method currently used for heavy metals in contaminated soils. House dust was collected from carpets in typical urban residences. Bioaccessible lead was measured in house dust (<75 microm) from the homes of 15 participants. The bioaccessibility ranged from 52.4% to 77.2% in gastric fluid, and 4.9% to 32.1% in intestinal fluid. House dust samples from five homes were analyzed to assess the relationship among lead bioaccessibility of three particle size fractions (<75, 75-150, and 150-250 microm). Changes in lead bioaccessibility as a function of particle size fraction were not significant for gastric fluid (p= 0.7019); however they were significant for intestinal fluid (p= 0.0067). This decrease of bioaccessibility may result from the readsorption of dissolved lead onto the dust particles or precipitation of lead with phosphates in a high-pH environment. The bioaccessibility data obtained for two biofluids were applied to the IEUBK model, and results for intestinal bioaccessibility of lead provide support for the model default value of 30% lead bioavailability of dust as a reasonable population indicator for dose, but the higher values for gastric bioaccessibility of lead appeared to provide an upper bound that approached actual blood lead levels in the children living in the studied homes. This upper bound

  14. What caused terrestrial dust loading and climate downturns between 533 and 540 A.D.?

    NASA Astrophysics Data System (ADS)

    Abbott, D. H.; Breger, D. L.; Biscaye, P. E.; Barron, J. A.; Juhl, R. A.; McCafferty, P.

    2013-12-01

    Sn-rich particles, Ni-rich particles and cosmic spherules are found together at four stratigraphic levels in the GISP2 ice core between 360 and 362 meters depth. Using a previously derived calendar-year time scale, these particles span a time of increased dust loading of the Earth's atmosphere between 533 and 540 A.D. The Sn enrichments suggest a cometary source for the dust. The late spring timing of extraterrestrial input best matches the Eta Aquarid meteor shower associated with comet 1P/Halley. The increased flux of cometary dust could explain a modest climate downturn in 533 A.D. The profound global dimming during 536 and 537 A.D. cannot be explained merely by a combination of cometary dust and a modest volcanic eruption. We found tropical marine microfossils at the end 535-start 536 A.D. level that we attribute to a low-latitude explosion in the ocean. This additional source of dust is probably needed to explain the solar dimming in 536-537 A.D. In addition, we found high-latitude marine diatoms and silicoflagellates at a second time horizon, circa 538 A.D. Some of the fossils are pre-Pleistocene in age, as old as Eocene. Both of these fossil-bearing stratigraphic levels contain enrichments of nitrate and ammonium in their supernatant water.

  15. Formation of dust particles under the influence of intense thermal loads

    NASA Astrophysics Data System (ADS)

    Koza, Y.; Berthe, E.; Lehmann, E.; Linke, J.; Rödig, M.; Wessel, E.; Singheiser, L.

    2004-08-01

    Intense thermal loads in fusion devices which occur during ELMs (edge localized modes), plasma disruptions and VDEs (vertical displacement events), will result in macroscopic erosion associated with the formation of cracks, droplets, evaporation, and melting, or sublimation. A fraction of dust particles will sublimate in the boundary plasma; others may be deposited in gaps and shadowed areas of the divertor region. Tritium uptake in these particles will be a critical issue in future thermonuclear fusion devices. Evaporation and the formation of tungsten droplets induced by boiling of tungsten may result in a severe contamination of the boundary plasma. In order to simulate the effect of dust formation under transient heat fluxes, heat load tests have been performed in the electron beam test facility JUDITH on tungsten and carbon based materials.

  16. TSCA Section 21 Petition Requesting EPA to Lower Lead Dust Hazard Standards and Modify the Definition of Lead-based Paint in its Regulations

    EPA Pesticide Factsheets

    This petition requests EPA to lower lead dust hazard standards and modify the definition of lead-based paint in its regulations promulgated under sections 401 and 403 of the Toxic Substances Control Act (TSCA).

  17. Numerical Model for Conduction-Cooled Current Lead Heat Loads

    SciTech Connect

    White, M.J.; Wang, X.L.; Brueck, H.D.; /DESY

    2011-06-10

    Current leads are utilized to deliver electrical power from a room temperature junction mounted on the vacuum vessel to a superconducting magnet located within the vacuum space of a cryostat. There are many types of current leads used at laboratories throughout the world; however, conduction-cooled current leads are often chosen for their simplicity and reliability. Conduction-cooled leads have the advantage of using common materials, have no superconducting/normal state transition, and have no boil-off vapor to collect. This paper presents a numerical model for conduction-cooled current lead heat loads. This model takes into account varying material and fluid thermal properties, varying thicknesses along the length of the lead, heat transfer in the circumferential and longitudinal directions, electrical power dissipation, and the effect of thermal intercepts. The model is validated by comparing the numerical model results to ideal cases where analytical equations are valid. In addition, the XFEL (X-Ray Free Electron Laser) prototype current leads are modeled and compared to the experimental results from testing at DESY's XFEL Magnet Test Stand (XMTS) and Cryomodule Test Bench (CMTB).

  18. Mobilization and distribution of lead originating from roof dust and wet deposition in a roof runoff system.

    PubMed

    Yu, Jianghua; Yu, Haixia; Huang, Xiaogu

    2015-12-01

    In this research, the mobilization and distribution of lead originating in roof dust and wet deposition were investigated within a roof dust-rooftop-runoff system. The results indicated that lead from roof dust and wet deposition showed different transport dynamics in runoff system and that this process was significantly influenced by the rainfall intensity. Lead present in the roof dust could be easily washed off into the runoff, and nearly 60 % of the total lead content was present in particulate form. Most of the lead from the roof dust was transported during the late period of rainfall; however, the lead concentration was higher for several minutes at the rainfall beginning. Even though some of the lead from wet deposition, simulated with a standard isotope substance, was adsorbed onto adhered roof dust and/or retained on rooftop in runoff system, most of it (50-82 %) remained as dissolved lead in the runoff for rainfall events of varying intensity. Regarding the distribution of lead in the runoff system, the results indicated that it could be carried in the runoff in dissolved and particulate form, be adsorbed to adhered roof dust, or remain on the rooftop because of adsorption to the roof material. Lead from the different sources showed different distribution patterns that were also related to the rainfall intensity. Higher rainfall intensity resulted in a higher proportion of lead in the runoff and a lower proportion of lead remaining on the rooftop.

  19. Solar Wind Mass-Loading Due to Dust in the Vicinity of the Sun

    NASA Astrophysics Data System (ADS)

    Rasca, A.; Horanyi, M.

    2012-12-01

    Collisionless shocks due to mass-loading were first discussed to describe the solar wind flow around a cometary atmosphere, showing its choking effects on the flow. Recent observations have led to an increased interest in mass-loading occurring in the solar corona, due to sun-grazing comets and also due to collisional debris production by sunward migrating interplanetary dust particles. Using one-dimensional simulations with a hydrodynamic model we have shown the impact on the solar wind from abrupt mass-loading in the coronal region. Full three-dimensional MHD simulations using the Block-Adaptive-Tree-Solarwind-Roe-Upwind-Scheme (BATS-R-US) accomplish more to mimic specific events applicable to modeling the mass-loaded coronal wind caused by the presence of a sun-grazing comet, for example.

  20. Lead concentrations and isotope ratios in street dust determined by electrothermal atomic absorption spectrometry and inductively coupled plasma mass spectrometry.

    PubMed

    Nageotte, S M; Day, J P

    1998-01-01

    A major source of environmental lead, particularly in urban areas, has been from the combustion of leaded petrol. Street dust has previously been used to assess urban lead contamination, and the dust itself can also be a potential source of lead ingestion, particularly to children. The progressive reduction of lead in petrol, in recent years, would be expected to have been reflected in a reduction of lead in urban dust. We have tested this hypothesis by repeating an earlier survey of Manchester street dust and carrying out a comparable survey in Paris. Samples were collected from streets and parks, lead was extracted by digestion with concentrated nitric acid and determined by electrothermal atomic absorption spectrometry. Lead isotope ratios were measured by inductively coupled plasma mass spectrometry. Results for Manchester show that lead concentrations have fallen by about 40% (street dust averages, 941 micrograms g-1 (ppm) in 1975 down to 569 ppm in 1997). In Paris, the lead levels in street dust are much higher and significant differences were observed between types of street (not seen in Manchester). Additionally, lead levels in parks were much lower than in Manchester. Samples collected under the Eiffel Tower had very high concentrations and lead isotope ratios showed that this was unlikely to be fallout from motor vehicles but could be due to the paint used on the tower. Isotope ratios measurements also revealed that lead additives used in France and the UK come from different sources.

  1. Using Engineering Cameras on Mars Landers and Rovers to Retrieve Atmospheric Dust Loading

    NASA Astrophysics Data System (ADS)

    Wolfe, C. A.; Lemmon, M. T.

    2014-12-01

    Dust in the Martian atmosphere influences energy deposition, dynamics, and the viability of solar powered exploration vehicles. The Viking, Pathfinder, Spirit, Opportunity, Phoenix, and Curiosity landers and rovers each included the ability to image the Sun with a science camera that included a neutral density filter. Direct images of the Sun provide the ability to measure extinction by dust and ice in the atmosphere. These observations have been used to characterize dust storms, to provide ground truth sites for orbiter-based global measurements of dust loading, and to help monitor solar panel performance. In the cost-constrained environment of Mars exploration, future missions may omit such cameras, as the solar-powered InSight mission has. We seek to provide a robust capability of determining atmospheric opacity from sky images taken with cameras that have not been designed for solar imaging, such as lander and rover engineering cameras. Operational use requires the ability to retrieve optical depth on a timescale useful to mission planning, and with an accuracy and precision sufficient to support both mission planning and validating orbital measurements. We will present a simulation-based assessment of imaging strategies and their error budgets, as well as a validation based on archival engineering camera data.

  2. Thermal structure and dust loading of the Martian atmosphere during late southern summer - Mariner 9 revisited

    NASA Astrophysics Data System (ADS)

    Santee, M.; Crisp, D.

    1993-02-01

    Thermal emission spectra recorded by the Mariner 9 IR interferometer spectrometer (IRIS) are used to investigate the temperature structure and dust loading of the Martian atmosphere. The analysis is restricted to a subset of the IRIS data consisting of approximately 2400 spectra in a 12-day period extending from LS of 343 to 348 deg, corresponding to late southern summer on Mars. The largest column-integrated 9-micron dust optical depths (about 0.4) occur over the equatorial regions. The highest atmospheric temperatures (greater than 260 K) are found at low altitudes near the subsolar latitude (about 6 deg S), while the coldest temperatures (less than 150 K) are found at levels near 1.0 mbar over the winter pole. The existence of a net zonally averaged meridional circulation with rising motion at low latitudes, poleward flow at altitudes above 40 km, and subsidence over the poles is suggested.

  3. Thermal structure and dust loading of the Martian atmosphere during late southern summer - Mariner 9 revisited

    NASA Technical Reports Server (NTRS)

    Santee, Michelle; Crisp, David

    1993-01-01

    Thermal emission spectra recorded by the Mariner 9 IR interferometer spectrometer (IRIS) are used to investigate the temperature structure and dust loading of the Martian atmosphere. The analysis is restricted to a subset of the IRIS data consisting of approximately 2400 spectra in a 12-day period extending from LS of 343 to 348 deg, corresponding to late southern summer on Mars. The largest column-integrated 9-micron dust optical depths (about 0.4) occur over the equatorial regions. The highest atmospheric temperatures (greater than 260 K) are found at low altitudes near the subsolar latitude (about 6 deg S), while the coldest temperatures (less than 150 K) are found at levels near 1.0 mbar over the winter pole. The existence of a net zonally averaged meridional circulation with rising motion at low latitudes, poleward flow at altitudes above 40 km, and subsidence over the poles is suggested.

  4. Dust load and rainfall characteristics and their relationship over the South Asian monsoon region under various warming scenarios

    NASA Astrophysics Data System (ADS)

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

    2017-08-01

    Present study investigates the similarities and differences in the pattern of dust load and rainfall and their relationship over the South Asian monsoon region under various future warming scenarios with respect to the historical period using multiple coupled climate model runs that participated in Coupled Model Inter-comparison Project Phase 5 (CMIP5). Based on statistically robust significance tests, we unravel several likely changes in the pattern of the dust load and rainfall over the South Asia under different future warming scenarios by the end of 21st century compared to the historical period. Kolmogorov-Smirnov test results reveal a significant change (at 5% significance level) in the amount of dust and rainfall under different warming scenarios over the study region. Northern part of the Indian subcontinent is likely to witness increased dust loading in future, and regions with increase in dust load are also likely to be the regions of increased rainfall over North India. Positive correlation between rainfall over the Indian region and dust over the Arabian region is also likely to strengthen in future. Considerable changes in the spatial correlation pattern between dust and rainfall are noted under different representative concentration pathways; however, no noteworthy changes are recorded in their temporal relationship. Notable intermodel differences in the patterns of dust load and rainfall relationship over South Asia are possibly caused by variations in the dust emission schemes among the CMIP5 models as well as the parameterization of aerosol indirect effect in addition to the differences in the meteorology simulated by various models under identical forcing scenarios.

  5. Variability of the Inter-Tropical Convergence Zone Related to Changes in Inter-Hemispheric Dust Load

    NASA Astrophysics Data System (ADS)

    Dawson, E.; Evans, S. M.; Ginoux, P. A.

    2016-12-01

    Dust is a key forcing agent in climate and has major societal impacts on health, agriculture, and transportation. Dust varies on inter-annual to millennial timescales up to a factor of 20 between glacial and interglacial periods. Over the 20th century, desert dust has doubled over much of the globe. In addition, dust has strong spatial heterogeneity producing disparate radiative forcing. Hemispheric asymmetry in dust concentrations has been observed between ice cores in Greenland and Antarctica and more recently between Australia and Africa in the 1970's. Our objective is to assess the impact of such hemispheric dust asymmetry on climate with an emphasis on the Inter-Tropical Convergence Zone (ITCZ). We perform a set of experiments with the GFDL coupled climate models (CM3), modifying dust emission in each hemisphere by 0, 1, 2, and 5 times preindustrial levels. Dust load follows the imposed emission, which reduces the net radiative flux at the surface and top of the atmosphere. When dust load is asymmetric, we find that the radiative forcing is similarly asymmetric, generating an inter-hemispheric transfer of energy through the atmosphere and ocean and an associated shift in precipitation along the ITCZ. We find a linear relationship between radiative forcing and tropical precipitation asymmetry in the Atlantic. Our results show that dust plays a significant role in determining the latitudinal position of the ITCZ. Understanding this relationship is crucial for accurately predicting dust feedbacks and the effects of dust on future climate. This relationship is also important for understanding past climate variability such as the mid-Holocene and Last Glacial Maximum.

  6. What caused terrestrial dust loading and climate downturns between A.D. 533 and 540?

    USGS Publications Warehouse

    Abbott, Dallas H.; Breger, Dee; Biscaye, Pierre E.; Barron, John A.; Juhl, Robert A.; McCafferty, Patrick

    2014-01-01

    Sn-rich particles, Ni-rich particles, and cosmic spherules are found together at four discrete stratigraphic levels within the 362-360 m depth interval of the Greenland Ice Sheet Project 2 (GISP2) ice core (72.6°N, 38.5°W, elevation: 3203 m). Using a previously derived calendar-year time scale, these particles span a time of increased dust loading of Earth's atmosphere between A.D. 533 and 540. The Sn-rich and Ni-rich particles contain an average of 10–11 wt% C. Their high C contents coupled with local enrichments in the volatile elements I, Zn, Cu, and Xe suggest a cometary source for the dust. The late spring timing of extraterrestrial input best matches the Eta Aquarid meteor shower associated with comet 1P/Halley. An increased flux of cometary dust might explain a modest climate downturn in A.D. 533. Both cometary dust and volcanic sulfate probably contributed to the profound global dimming during A.D. 536 and 537 but may be insufficient sources of fine aerosols. We found tropical marine microfossils and aerosol-sized CaCO3 particles at the end A.D. 535–start A.D. 536 level that we attribute to a low-latitude explosion in the ocean. This additional source of dust is probably needed to explain the solar dimming during A.D. 536 and 537. Although there has been no extinction documented at A.D. 536, our results are relevant because mass extinctions may also have multiple drivers. Detailed examinations of fine particles at and near extinction horizons can help to determine the relative contributions of cosmic and volcanic drivers to mass extinctions.

  7. Retrieving Atmospheric Dust Loading on Mars Using Engineering Cameras and MSL's Mars Hand Lens Imager (MAHLI)

    NASA Astrophysics Data System (ADS)

    Wolfe, C. A.; Lemmon, M. T.

    2015-12-01

    Dust in the Martian atmosphere influences energy deposition, dynamics, and the viability of solar powered exploration vehicles. The Viking, Pathfinder, Spirit, Opportunity, Phoenix, and Curiosity landers and rovers each included the ability to image the Sun with a science camera equipped with a neutral density filter. Direct images of the Sun not only provide the ability to measure extinction by dust and ice in the atmosphere, but also provide a variety of constraints on the Martian dust and water cycles. These observations have been used to characterize dust storms, to provide ground truth sites for orbiter-based global measurements of dust loading, and to help monitor solar panel performance. In the cost-constrained environment of Mars exploration, future missions may omit such cameras, as the solar-powered InSight mission has. We seek to provide a robust capability of determining atmospheric opacity from sky images taken with cameras that have not been designed for solar imaging, such as the engineering cameras onboard Opportunity and the Mars Hand Lens Imager (MAHLI) on Curiosity. Our investigation focuses primarily on the accuracy of a method that determines optical depth values using scattering models that implement the ratio of sky radiance measurements at different elevation angles, but at the same scattering angle. Operational use requires the ability to retrieve optical depth on a timescale useful to mission planning, and with an accuracy and precision sufficient to support both mission planning and validating orbital measurements. We will present a simulation-based assessment of imaging strategies and their error budgets, as well as a validation based on the comparison of direct extinction measurements from archival Navcam, Hazcam, and MAHLI camera data.

  8. Measurement of circumsolar ratio in high dust loading regions using a photographic method

    NASA Astrophysics Data System (ADS)

    Al-Ansary, Hany; Shafiq, Talha; Rizvi, Arslan; El-Leathy, Abdelrahman

    2017-06-01

    Performance of concentrating solar power (CSP) plants is highly affected by direct normal irradiance (DNI). However, it is also important to consider circumsolar radiation in any simulation of a CSP plant, especially in desert regions where dust loading in the atmosphere is expected. There are a number of methods to measure circumsolar radiation. However, most of them require expensive instrumentation. This work introduces a simple method to estimate circumsolar radiation. It involves taking high-resolution photographs of the sun and processing them using a computer code that identifies the sun's disk. The code then uses pixel intensities to obtain the solar intensity distribution across the sun's disk and in the aureole region. The solar intensity distribution is then used to obtain the circumsolar ratio (CSR) which represents the shape of the sun. To test this method, numerous photos of the sun were taken during the month of April and September 2016 at King Saud University in Riyadh, Saudi Arabia. Riyadh is a region that is well known for high dust-loading, especially during the summer. Two days of different atmospheric conditions were selected in September for comparative analysis. Results show that this method produces repeatable results, and that the CSR can increase significantly due to high dust loading and passing clouds. The CSR is found to be a strong function of DNI, ranging from about 4.5% at DNI values above 800 W/m2 and increasing to as much as 8.5% when DNI drops to about 400 W/m2, due to passing clouds. Furthermore, the results show that circumsolar ratio tends to be high in the early morning and late afternoon due to the high air mass, while its values tend to be lowest around solar noon when the air mass is lowest.

  9. Properties of interstellar wind leading to shape morphology of the dust surrounding HD 61005

    NASA Astrophysics Data System (ADS)

    Pástor, P.

    2017-08-01

    Aims: A structure formed by dust particles ejected from the debris ring around HD 61005 is observed in the scattered light. The main aim here is to constrain interstellar wind parameters that lead to shape morphology in the vicinity of HD 61005 using currently available observational data for the debris ring. Methods: Equation of motion of 2 × 105 dust particles ejected from the debris ring under the action of the electromagnetic radiation, stellar wind, and interstellar wind is solved. A two-dimensional (2D) grid is placed in a given direction for accumulation of the light scattered on the dust particles in order to determine the shape morphology. The interaction of the interstellar wind and the stellar wind is considered. Results: Groups of unknown properties of the interstellar wind that create the observed morphology are determined. A relation between number densities of gas components in the interstellar wind and its relative velocity is found. Variations of the shape morphology caused by the interaction with the interstellar clouds of various temperatures are studied. When the interstellar wind velocity is tilted from debris ring axis a simple relation between the properties of the interstellar wind and an angle between the line of sight and the interstellar wind velocity exists. Dust particles that are most significantly influenced by stellar radiation move on the boundary of observed structure. Conclusions: Observed structure at HD 61005 can be explained as a result of dust particles moving under the action of the interstellar wind. Required number densities or velocities of the interstellar wind are much higher than that of the interstellar wind entering the solar system.

  10. Relative Contributions of the Saharan and Sahelian Sources to the Atmospheric Dust Load Over the North Atlantic

    NASA Technical Reports Server (NTRS)

    Ginoux, Paul; Chin, M.; Torres, O.; Prospero, J.; Dubovik, O.; Holben, B.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    It has long been recognized that Saharan desert is the major source for long range transport of mineral dust over the Atlantic. The contribution from other natural sources to the dust load over the Atlantic has generally been ignored in previous model studies or been replaced by anthropogenically disturbed soil emissions. Recently, Prospero et.at. have identified the major dust sources over the Earth using TOMS aerosol index. They showed that these sources correspond to dry lakes with layers of sediment deposed in the late Holocene or Pleistocene. One of the most active of these sources seem to be the Bodele depression. Chiapello et al. have analyzed the mineralogical composition of dust on the West coast of Africa. They found that Sahelian dust events are the most intense but are less frequent than Saharan plumes. This suggests that the Bodele depression could contribute significantly to the dust load over the Atlantic. The relative contribution of the Sahel and Sahara dust sources is of importance for marine biogeochemistry or atmospheric radiation, because each source has a distinct mineralogical composition. We present here a model study of the relative contributions of Sahara and Sahel sources to the atmospheric dust aerosols over the North Atlantic. The Georgia Tech/Goddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) model is used to simulate dust distribution in 1996-1997. Dust particles are labeled depending on their sources. In this presentation, we will present the comparison between the model results and observations from ground based measurements (dust concentration, optical thickness and size distribution) and satellite data (TOMS aerosol index). The relative contribution of each source will then be analyzed spatially and temporally.

  11. Relative Contributions of the Saharan and Sahelian Sources to the Atmospheric Dust Load Over the North Atlantic

    NASA Technical Reports Server (NTRS)

    Ginoux, Paul; Chin, M.; Torres, O.; Prospero, J.; Dubovik, O.; Holben, B.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    It has long been recognized that Saharan desert is the major source for long range transport of mineral dust over the Atlantic. The contribution from other natural sources to the dust load over the Atlantic has generally been ignored in previous model studies or been replaced by anthropogenically disturbed soil emissions. Recently, Prospero et.at. have identified the major dust sources over the Earth using TOMS aerosol index. They showed that these sources correspond to dry lakes with layers of sediment deposed in the late Holocene or Pleistocene. One of the most active of these sources seem to be the Bodele depression. Chiapello et al. have analyzed the mineralogical composition of dust on the West coast of Africa. They found that Sahelian dust events are the most intense but are less frequent than Saharan plumes. This suggests that the Bodele depression could contribute significantly to the dust load over the Atlantic. The relative contribution of the Sahel and Sahara dust sources is of importance for marine biogeochemistry or atmospheric radiation, because each source has a distinct mineralogical composition. We present here a model study of the relative contributions of Sahara and Sahel sources to the atmospheric dust aerosols over the North Atlantic. The Georgia Tech/Goddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) model is used to simulate dust distribution in 1996-1997. Dust particles are labeled depending on their sources. In this presentation, we will present the comparison between the model results and observations from ground based measurements (dust concentration, optical thickness and size distribution) and satellite data (TOMS aerosol index). The relative contribution of each source will then be analyzed spatially and temporally.

  12. Dust detector using piezoelectric lead zirconate titanate with current-to-voltage converting amplifier for functional advancement

    NASA Astrophysics Data System (ADS)

    Kobayashi, Masanori; Miyachi, Takashi; Hattori, Maki; Sugita, Seiji; Takechi, Seiji; Okada, Nagaya

    2013-03-01

    This paper describes the concept of a dust monitor using lead zirconate titanate (PZT) ceramics with a large detection area. Its potential as a dust detector is experimentally demonstrated. The dust monitor has a small volume compared to an impact ionization detector with the same detection area, due to the PZT sensor. The PZT sensor, as a traditional device for the in-situ observation of hypervelocity dust particles, has been used for momentum measurement. The hypervelocity impact signals of PZT sensors are typically read by charge-sensitive amplifiers. Instead, we suggest a new method that a current-to-voltage converting amplifier is useful for interpreting the impact signal of a PZT sensor arising from dust particles down to 0.5 μm in radius. We propose that datasets of dust impacts can be obtained with a higher statistical accuracy, if the new method is applied to instruments on forthcoming interplanetary-space-cruising spacecrafts.

  13. Investigating the relationship between lead speciation and bioaccessibility of mining impacted soils and dusts.

    PubMed

    Liu, Yanju; Bello, Olanrewaju; Rahman, Mohammad Mahmudur; Dong, Zhaomin; Islam, Shofiqul; Naidu, Ravi

    2017-07-01

    Lead (Pb) bioaccessibility measurements have been the subject of much research in recent years, given the desire to develop a cost-effective and reliable alternative method to estimate its bioavailability from soils and dusts. This study investigates the relationship between Pb bioaccessibility estimated using the Relative Bioavailability Leaching Procedure (RBALP) and solid phase speciation of Pb using mining impacted soils and associated dusts. Solid phase speciation was conducted prior to and after RBALP extractions. The average Pb concentrations were 59, 67, and 385 mg/kg for top soil, sub-soil, and house dust samples, respectively. Lead bioaccessibility in selected top soils and dusts ranged from 16.7 to 57.3% and 8.9 to 98.1%, respectively. Solid phase speciation of Pb in <250 μm residues prior to and after RBALP extraction revealed 83% decrease in Pb bound to carbonate fraction after RBALP extraction. This accounts for 69% of RBALP-extractable Pb. Besides contribution from carbonate bound Pb, 76.6 and 53.2% of Pb bound to Mn oxyhydroxides and amorphous Fe and Al oxyhydroxides contributed to bioaccessible Pb, respectively. However, Pb bound to Mn oxyhydroxides and amorphous Fe and Al oxyhydroxides account for only 13.8 and 20.0% of total RBALP-extractable Pb, respectively. Both non-specifically bound and easily exchangeable fractions and strongly bound inner-sphere complexes were also part of bioaccessible Pb. The present study demonstrates that bioaccessible Pb is released from both soil solution phase Pb as well as that from all soil solid phase with the most contribution being from Pb bound to carbonate mineral phase.

  14. [Shielding ability of lead loaded radiation resistant gloves].

    PubMed

    Kawano, T; Ebihara, H

    1990-02-01

    The shielding ability of radiation resistant gloves was examined. The gloves are made of lead loaded (as PbO2) polyvinyl chloride resin and are about 0.4 mm in thickness (70 mg/cm2). Eleven test pieces were sampled from each of three gloves (total 33) and the transmission rates for radiations (X-ray or gamma-ray) through the test pieces were measured with radiation sources, 99mTc, 57Co, 133Ba, 133Xe and 241Am. The differences of the transmission rates for radiations by the positions of the gloves were smaller than 15%, and the differences by three gloves were smaller than 5% in the case of 60 keV and 141 keV radiations. The average transmission rates for radiations in the 33 test pieces were about 40% for 30 keV radiation, about 90% for 80 keV and 140 keV radiations. The shielding characteristic of the gloves is equivalent to about 0.026 mm thick lead plate.

  15. Lead in United Kingdom soils and dusts in relation to environmental standards and guidelines

    SciTech Connect

    Thornton, I.

    1986-01-01

    Concentrations of lead in British soils are frequently elevated due to both natural and man-made sources. A long history of mining and smelting has resulted in extensive metal pollution in specific areas. These extend to some 6000 sq km of agricultural land and include some small towns and villages. In these geochemical hot-spot areas lead passes in limited amounts into the food chain resulting in moderate elevations in blood lead concentrations in both grazing livestock and in children living in the old mining communities. There are no reported adverse effects on the health of livestock or the human population. A national survey of metals in dusts and soils in urban areas of Britain has shown elevated concentrations of lead in a significant proportion of households particularly those sampled in London. The results of this survey are compared with national standards and guidelines. 22 references, 3 tables.

  16. Isotopically constrained lead sources in fugitive dust from unsurfaced roads in the southeast Missouri mining district.

    PubMed

    Witt, Emitt C; Pribil, Michael J; Hogan, John P; Wronkiewicz, David J

    2016-09-01

    The isotopic composition of lead (Pb) in fugitive dust suspended by a vehicle from 13 unsurfaced roads in Missouri was measured to identify the source of Pb within an established long-term mining area. A three end-member model using (207)Pb/(206)Pb and concentration as tracers resulted in fugitive dust samples plotting in the mixing field of well characterized heterogeneous end members. End members selected for this investigation include the (207)Pb/(206)Pb for 1) a Pb-mixture representing mine tailings, 2) aerosol Pb-impacted soils within close proximity to the Buick secondary recycling smelter, and 3) an average of soils, rock cores and drill cuttings representing the background conditions. Aqua regia total concentrations and (207)Pb/(206)Pb of mining area dust suggest that 35.4-84.3% of the source Pb in dust is associated with the mine tailings mixture, 9.1-52.7% is associated with the smelter mixture, and 0-21.6% is associated with background materials. Isotope ratios varied minimally within the operational phases of sequential extraction suggesting that mixing of all three Pb mixtures occurs throughout. Labile forms of Pb were attributed to all three end members. The extractable carbonate phase had as much as 96.6% of the total concentration associated with mine tailings, 51.8% associated with smelter deposition, and 34.2% with background. The next most labile geochemical phase (Fe + Mn Oxides) showed similar results with as much as 85.3% associated with mine tailings, 56.8% associated with smelter deposition, and 4.2% associated with the background soil. Published by Elsevier Ltd.

  17. Isotopically constrained lead sources in fugitive dust from unsurfaced roads in the southeast Missouri mining district

    USGS Publications Warehouse

    Witt, Emitt C.; Pribil, Michael; Hogan, John P; Wronkiewicz, David

    2016-01-01

    The isotopic composition of lead (Pb) in fugitive dust suspended by a vehicle from 13 unsurfaced roads in Missouri was measured to identify the source of Pb within an established long-term mining area. A three end-member model using 207Pb/206Pb and concentration as tracers resulted in fugitive dust samples plotting in the mixing field of well characterized heterogeneous end members. End members selected for this investigation include the 207Pb/206Pb for 1) a Pb-mixture representing mine tailings, 2) aerosol Pb-impacted soils within close proximity to the Buick secondary recycling smelter, and 3) an average of soils, rock cores and drill cuttings representing the background conditions. Aqua regia total concentrations and 207Pb/206Pb of mining area dust suggest that 35.4–84.3% of the source Pb in dust is associated with the mine tailings mixture, 9.1–52.7% is associated with the smelter mixture, and 0–21.6% is associated with background materials. Isotope ratios varied minimally within the operational phases of sequential extraction suggesting that mixing of all three Pb mixtures occurs throughout. Labile forms of Pb were attributed to all three end members. The extractable carbonate phase had as much as 96.6% of the total concentration associated with mine tailings, 51.8% associated with smelter deposition, and 34.2% with background. The next most labile geochemical phase (Fe + Mn Oxides) showed similar results with as much as 85.3% associated with mine tailings, 56.8% associated with smelter deposition, and 4.2% associated with the background soil.

  18. Lead speciation in indoor dust: a case study to assess old paint contribution in a Canadian urban house

    SciTech Connect

    Beauchemin, Suzanne; MacLean, Lachlan C.W.; Rasmussen, Pat E.

    2012-10-23

    Residents in older homes may experience increased lead (Pb) exposures due to release of lead from interior paints manufactured in past decades, especially pre-1960s. The objective of the study was to determine the speciation of Pb in settled dust from an urban home built during WWII. X-ray absorption near-edge structure (XANES) and micro-X-ray diffraction (XRD) analyses were performed on samples of paint (380-2,920 mg Pb kg{sup -1}) and dust (200-1,000 mg Pb kg{sup -1}) collected prior to renovation. All dust samples exhibited a Pb XANES signature similar to that of Pb found in paint. Bulk XANES and micro-XRD identified Pb species commonly found as white paint pigments (Pb oxide, Pb sulfate, and Pb carbonate) as well as rutile, a titanium-based pigment, in the <150 {micro}m house dust samples. In the dust fraction <36 {micro}m, half of the Pb was associated with the Fe-oxyhydroxides, suggesting additional contribution of outdoor sources to Pb in the finer dust. These results confirm that old paints still contribute to Pb in the settled dust for this 65-year-old home. The Pb speciation also provided a clearer understanding of the Pb bioaccessibility: Pb carbonate > Pb oxide > Pb sulfate. This study underscores the importance of taking precautions to minimize exposures to Pb in house dust, especially in homes where old paint is exposed due to renovations or deterioration of painted surfaces.

  19. Lead Speciation in Indoor Dust: A Case Study to Assess Old Paint Contribution in a Canadian Urban House

    SciTech Connect

    S Beauchemin; L MacLean; P Rasmussen

    2011-12-31

    Residents in older homes may experience increased lead (Pb) exposures due to release of lead from interior paints manufactured in past decades, especially pre-1960s. The objective of the study was to determine the speciation of Pb in settled dust from an urban home built during WWII. X-ray absorption near-edge structure (XANES) and micro-X-ray diffraction (XRD) analyses were performed on samples of paint (380-2,920 mg Pb kg{sup -1}) and dust (200-1,000 mg Pb kg{sup -1}) collected prior to renovation. All dust samples exhibited a Pb XANES signature similar to that of Pb found in paint. Bulk XANES and micro-XRD identified Pb species commonly found as white paint pigments (Pb oxide, Pb sulfate, and Pb carbonate) as well as rutile, a titanium-based pigment, in the <150 m house dust samples. In the dust fraction <36 {mu}m, half of the Pb was associated with the Fe-oxyhydroxides, suggesting additional contribution of outdoor sources to Pb in the finer dust. These results confirm that old paints still contribute to Pb in the settled dust for this 65-year-old home. The Pb speciation also provided a clearer understanding of the Pb bioaccessibility: Pb carbonate > Pb oxide > Pb sulfate. This study underscores the importance of taking precautions to minimize exposures to Pb in house dust, especially in homes where old paint is exposed due to renovations or deterioration of painted surfaces.

  20. Environmental arsenic, cadmium and lead dust emissions from metal mine operations: Implications for environmental management, monitoring and human health

    SciTech Connect

    Taylor, Mark Patrick Mould, Simon Anthony; Kristensen, Louise Jane; Rouillon, Marek

    2014-11-15

    Although blood lead values in children are predominantly falling globally, there are locations where lead exposure remains a persistent problem. One such location is Broken Hill, Australia, where the percentage of blood lead values >10 μg/dL in children aged 1–4 years has risen from 12.6% (2010), to 13% (2011) to 21% (2012). The purpose of this study was to determine the extent of metal contamination in places accessible to children. This study examines contemporary exposure risks from arsenic, cadmium, lead, silver and zinc in surface soil and dust, and in pre- and post-play hand wipes at six playgrounds across Broken Hill over a 5-day period in September 2013. Soil lead (mean 2,450 mg/kg) and zinc (mean 3,710 mg/kg) were the most elevated metals in playgrounds. Surface dust lead concentrations were consistently elevated (mean 27,500 μg/m{sup 2}) with the highest lead in surface dust (59,900 μg/m{sup 2}) and post-play hand wipes (60,900 μg/m{sup 2}) recorded close to existing mining operations. Surface and post-play hand wipe dust values exceeded national guidelines for lead and international benchmarks for arsenic, cadmium and lead. Lead isotopic compositions ({sup 206}Pb/{sup 207}Pb, {sup 208}Pb/{sup 207}Pb) of surface dust wipes from the playgrounds revealed the source of lead contamination to be indistinct from the local Broken Hill ore body. The data suggest frequent, cumulative and ongoing mine-derived dust metal contamination poses a serious risk of harm to children. - Highlights: 1.Playground soils and surface dust in a mining town have high metal concentrations. 2.Elevated levels of As, Cd, Pb and Zn dust are found on playground users′ hands. 3.Pb isotope analysis shows that the source of playground dust is ore body Pb. 4.Surface mine operations must be contained to reduce childhood lead exposure risks. 5.Mine environmental licences need to set trigger values for As, Cd, Pb and Zn dust.

  1. Lead (Pb) legacy from vehicle traffic in eight California urbanized areas: continuing influence of lead dust on children's health.

    PubMed

    Mielke, Howard W; Laidlaw, Mark A S; Gonzales, Chris

    2010-09-01

    This article describes the magnitude of U.S. lead (Pb) additives in gasoline from 1927 to 1994 and estimated quantities of Pb dispersed by vehicle traffic in eight urbanized areas (UAs) of California from 1950 to 1982. The findings are the basis for predicting the health impact of Pb on children living in UA of California. Quantitative U.S. national data for 1927-1994 were from the U.S. Senate hearing of the 1984 Airborne Lead Reduction Act. Vehicle traffic data, fuel efficiency, percentage leaded gasoline, and quantities of Pb in gasoline were obtained for 1982 from public and corporate records to estimate vehicle Pb emissions for small to very large UAs of California. California fuel consumption records and yearly quantities of Pb additives per gallon were the basis for estimating the 1950-1982 dispersion of Pb in each UA. Lead additives were calculated by multiplying annual vehicle fuel used by average Pb per gallon. The proportion of Pb additive for each UA was calculated from vehicle miles traveled (VMT) driven in 1982 divided by miles per gallon fuel consumption times the ratio of leaded to unleaded fuel times Pb additive per gallon. U.S. Environmental Protection Agency calculations of the fates of Pb were used to estimate Pb aerosol dispersal in each UA. About 108 billion miles of travel in 1982 within 8 UAs accounts for 3200metric tons of Pb additives or approximately 60% total Pb additives in California. Between the 1950-1982 peak of Pb additives, about 258,000metric tons are accounted for out of the state 412,000metric tons total during the same time period. The estimates of the quantities of Pb dust that accumulated within various UAs in California assists with predicting the continuing influences of Pb on children's exposure. Mapping the soil Pb reservoir assists with establishing the priority for enhancing environments of children. Copyright 2010 Elsevier B.V. All rights reserved.

  2. 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

  3. 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.

  4. Lead and other elements in house dust of Japanese residences--source of lead and health risks due to metal exposure.

    PubMed

    Yoshinaga, Jun; Yamasaki, Kumiko; Yonemura, Ayumi; Ishibashi, Yuri; Kaido, Takaya; Mizuno, Kodai; Takagi, Mai; Tanaka, Atsushi

    2014-06-01

    The levels of 25 elements in house dust collected from 100 general Japanese residences were measured. Factor analysis was applied on the multi-element data to explore source of Pb (median concentration 49.1 mg/kg) in house dust. Six factors were extracted and Pb was found to have great loading on the fifth factor with Sb and Sn, suggesting solder (Sn), and plastic and metals (Sb) may be the sources of Pb in the house dust of Japanese residences. No significant loading was found on soil-related factors indicating non-significant contribution of Pb in track-in soil. Seven heavy metals (Cd, Cu, Mo, Pb, Sb, Sn, and Zn) were found in house dust at >10 times more condensed than crustal abundance. Health risk of these elements to children via the ingestion of house dust was estimated based on the comparison with tolerable daily intake and found to be non-significant for most of the elements.

  5. Assessing remedial effectiveness through the blood lead:soil/dust lead relationship at the Bunker Hill Superfund Site in the Silver Valley of Idaho.

    PubMed

    von Lindern, Ian; Spalinger, Susan; Petroysan, Varduhi; von Braun, Margrit

    2003-02-15

    The 21 square mile Bunker Hill Superfund Site in northern Idaho includes several thousand acres of contaminated hillsides and floodplain, a 365-acre abandoned lead/zinc smelter and is home to more than 7000 people in 5 residential communities. Childhood lead poisoning was epidemic in the 1970s with >75% of children exceeding 40 microg/dl blood lead. Health response activities have been ongoing for three decades. In 1991, a blood lead goal of 95% of children with levels less than 10 microg/dl was adopted. The cleanup strategy, based on biokinetic pathways models, was to reduce house dust lead exposure through elimination of soil-borne sources. An interim health intervention program, that included monitoring blood lead and exposures levels, was instituted to reduce exposures through parental education during the cleanup. In 1989 and 2001, 56% and 3% of children, respectively, exceeded the blood lead criteria. More than 4000 paired blood lead/environmental exposure observations were collected during this period. Several analyses of these data were accomplished. Slope factors derived for the relationship between blood lead, soil and dust concentrations are age-dependent and similar to literature reported values. Repeat measures analysis assessing year to year changes found that the remediation effort (without intervention) had approximately a 7.5 microg/dl effect in reducing a 2-year-old child's mean blood lead level over the course of the last ten years. Those receiving intervention had an additional 2-15 microg/dl decrease. Structural equations models indicate that from 40 to 50% of the blood lead absorbed from soils and dusts is through house dust with approximately 30% directly from community-wide soils and 30% from the home yard and immediate neighborhood. Both mean blood lead levels and percent of children to exceed 10 microg/dl have paralleled soil/dust lead intake rates estimated from the pathways model. Application of the IEUBK model for lead indicates that

  6. The impact of drinking water, indoor dust and paint on blood lead levels of children aged 1-5 years in Montréal (Québec, Canada).

    PubMed

    Levallois, Patrick; St-Laurent, Julie; Gauvin, Denis; Courteau, Marilène; Prévost, Michèle; Campagna, Céline; Lemieux, France; Nour, Shokoufeh; D'Amour, Monique; Rasmussen, Pat E

    2014-01-01

    Lead is neurotoxic at very low dose and there is a need to better characterize the impact of domestic sources of lead on the biological exposure of young children. A cross-sectional survey evaluated the contribution of drinking water, house dust and paint to blood lead levels (BLLs) of young children living in old boroughs of Montréal (Canada). Three hundred and six children aged 1 to 5 years and currently drinking tap water participated in the study. For each participant, residential lead was measured in kitchen tap water, floor dust, windowsill dust and house paint and a venous blood sample was analyzed. Multivariate logistic regression was used to evaluate the association between elevated BLL in the children (≥ 75th percentile) and indoor lead contamination by means of odds ratios (OR) using 95% confidence intervals (CI). There was an association between BLL ≥75th percentile (1.78 μg/dL) and water lead when the mean water concentration was >3.3 μg/L: adjusted OR=4.7 (95% CI: 2.1-10.2). Windowsill dust loading >14.1 μg/ft(2) was also associated with BLL ≥1.78 μg/dL: adjusted OR=3.2 (95% CI: 1.3-7.8). Despite relatively low BLLs, tap water and house dust lead contribute to an increase of BLLs in exposed young children.

  7. The impact of drinking water, indoor dust and paint on blood lead levels of children aged 1–5 years in Montréal (Québec, Canada)

    PubMed Central

    Levallois, Patrick; St-Laurent, Julie; Gauvin, Denis; Courteau, Marilène; Prévost, Michèle; Campagna, Céline; Lemieux, France; Nour, Shokoufeh; D'Amour, Monique; Rasmussen, Pat E

    2014-01-01

    Lead is neurotoxic at very low dose and there is a need to better characterize the impact of domestic sources of lead on the biological exposure of young children. A cross-sectional survey evaluated the contribution of drinking water, house dust and paint to blood lead levels (BLLs) of young children living in old boroughs of Montréal (Canada). Three hundred and six children aged 1 to 5 years and currently drinking tap water participated in the study. For each participant, residential lead was measured in kitchen tap water, floor dust, windowsill dust and house paint and a venous blood sample was analyzed. Multivariate logistic regression was used to evaluate the association between elevated BLL in the children (≥ 75th percentile) and indoor lead contamination by means of odds ratios (OR) using 95% confidence intervals (CI). There was an association between BLL ≥75th percentile (1.78 μg/dL) and water lead when the mean water concentration was >3.3 μg/L: adjusted OR=4.7 (95% CI: 2.1–10.2). Windowsill dust loading >14.1 μg/ft2 was also associated with BLL ≥1.78 μg/dL: adjusted OR=3.2 (95% CI: 1.3–7.8). Despite relatively low BLLs, tap water and house dust lead contribute to an increase of BLLs in exposed young children. PMID:23361441

  8. Exposure of U.S. Children to Residential Dust Lead, 1999–2004: I. Housing and Demographic Factors

    PubMed Central

    Gaitens, Joanna M.; Dixon, Sherry L.; Jacobs, David E.; Nagaraja, Jyothi; Strauss, Warren; Wilson, Jonathan W.; Ashley, Peter J.

    2009-01-01

    Background Lead-contaminated house dust is a major source of lead exposure for children in the United States. In 1999–2004, the National Health and Nutrition Examination Survey (NHANES) collected dust lead (PbD) loading samples from the homes of children 12–60 months of age. Objectives In this study we aimed to compare national PbD levels with existing health-based standards and to identify housing and demographic factors associated with floor and windowsill PbD. Methods We used NHANES PbD data (n = 2,065 from floors and n = 1,618 from windowsills) and covariates to construct linear and logistic regression models. Results The population-weighted geometric mean floor and windowsill PbD were 0.5 μg/ft2 [geometric standard error (GSE) = 1.0] and 7.6 μg/ft2 (GSE = 1.0), respectively. Only 0.16% of the floors and 4.0% of the sills had PbD at or above current federal standards of 40 and 250 μg/ft2, respectively. Income, race/ethnicity, floor surface/condition, windowsill PbD, year of construction, recent renovation, smoking, and survey year were significant predictors of floor PbD [the proportion of variability in the dependent variable accounted for by the model (R2) = 35%]. A similar set of predictors plus the presence of large areas of exterior deteriorated paint in pre-1950 homes and the presence of interior deteriorated paint explained 20% of the variability in sill PbD. A companion article [Dixon et al. Environ Health Perspect 117:468–474 (2009)] describes the relationship between children’s blood lead and PbD. Conclusion Most houses with children have PbD levels that comply with federal standards but may put children at risk. Factors associated with PbD in our population-based models are primarily the same as factors identified in smaller at-risk cohorts. PbD on floors and windowsills should be kept as low as possible to protect children. PMID:19337523

  9. Evaluation of Ag nanoparticle coated air filter against aerosolized virus: Anti-viral efficiency with dust loading.

    PubMed

    Joe, Yun Haeng; Park, Dae Hoon; Hwang, Jungho

    2016-01-15

    In this study, the effect of dust loading on the anti-viral ability of an anti-viral air filter was investigated. Silver nanoparticles approximately 11 nm in diameter were synthesized via a spark discharge generation system and were used as anti-viral agents coated onto a medium air filter. The pressure drop, filtration efficiency, and anti-viral ability of the filter against aerosolized bacteriophage MS2 virus particles were tested with dust loading. The filtration efficiency and pressure drop increased with dust loading, while the anti-viral ability decreased. Theoretical analysis of anti-viral ability with dust loading was carried out using a mathematical model based on that presented by Joe et al. (J. Hazard. Mater.; 280: 356-363, 2014). Our model can be used to compare anti-viral abilities of various anti-viral agents, determine appropriate coating areal density of anti-viral agent on a filter, and predict the life cycle of an anti-viral filter. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Characteristics of PAHs in street dust of Beijing and the annual wash-off load using an improved load calculation method.

    PubMed

    Li, Yingxia; Song, Ningning; Yu, Yang; Yang, Zhifeng; Shen, Zhenyao

    2017-03-01

    A significant amount of polycyclic aromatic hydrocarbons (PAHs) adsorbed in street dust ends up in runoff. Accordingly, evaluating the content, possible wash-off load and constituent risks associated with street dust is critical for urban runoff usage. Based on the PAH concentrations examined in this study, different risk assessment methods were applied and the differences among results were analyzed. An improved PAH wash-off calculation method was established and the annual PAH wash-off load was obtained. In addition, emission sources were diagnosed based on isomer ratios and PMF methods. The overall mean ΣPAHs (sum of 16 individual PAHs) concentration in the street dust was 3.70μg/g, with the highest mean concentrations found for main roads (5.18μg/g). Adjacent anthropogenic activities had a greater effect on pollution characteristics of street dust than land use types. The toxic risk order was park (0.64μg/g)>main road (0.57μg/g)>residence (0.32μg/g)>street (0.29μg/g)>commerce (0.23μg/g), while that of the ecological risk index was main road (1278)>street (920)>residence (904)>commerce (713)>park (195). Although the park sites had a high level of toxic risk, they showed low ecological risk because they had less dust mass per unit area, indicating a great difference in the risk evaluation results and the difference methods. Using different values for different magnitudes of the antecedent dry days, rainfall event amounts, and dust mass fraction of different size ranges, the average wash-off load of ΣPAHs from street dust was calculated to be 23kg per year in Beijing from 2000 to 2014 with an improved wash-off load calculation method. The main sources of PAHs in the street dust of Beijing's center were identified as gasoline emissions, diesel emissions, coal combustion and unburned petroleum.

  11. Lead speciation in indoor dust: a case study to assess old paint contribution in a Canadian urban house.

    PubMed

    Beauchemin, Suzanne; MacLean, Lachlan C W; Rasmussen, Pat E

    2011-08-01

    Residents in older homes may experience increased lead (Pb) exposures due to release of lead from interior paints manufactured in past decades, especially pre-1960s. The objective of the study was to determine the speciation of Pb in settled dust from an urban home built during WWII. X-ray absorption near-edge structure (XANES) and micro-X-ray diffraction (XRD) analyses were performed on samples of paint (380-2,920 mg Pb kg(-1)) and dust (200-1,000 mg Pb kg(-1)) collected prior to renovation. All dust samples exhibited a Pb XANES signature similar to that of Pb found in paint. Bulk XANES and micro-XRD identified Pb species commonly found as white paint pigments (Pb oxide, Pb sulfate, and Pb carbonate) as well as rutile, a titanium-based pigment, in the <150 μm house dust samples. In the dust fraction <36 μm, half of the Pb was associated with the Fe-oxyhydroxides, suggesting additional contribution of outdoor sources to Pb in the finer dust. These results confirm that old paints still contribute to Pb in the settled dust for this 65-year-old home. The Pb speciation also provided a clearer understanding of the Pb bioaccessibility: Pb carbonate > Pb oxide > Pb sulfate. This study underscores the importance of taking precautions to minimize exposures to Pb in house dust, especially in homes where old paint is exposed due to renovations or deterioration of painted surfaces.

  12. Garden soil and house dust as exposure media for lead uptake in the mining village of Stratoni, Greece.

    PubMed

    Argyraki, Ariadne

    2014-08-01

    The relationships between two exposure media, garden soil and house dust, were studied for Pb uptake in Stratoni village in northern Greece, an industrial area of mining and processing of sulphide ore. Lead data for the two media were assessed in terms of total and bioaccessible content, measurement and geochemical variability, and mineralogical composition. It was found that total Pb was enriched in house dust samples by a factor of 2 on average. Total Pb concentration in soil samples had a maximum of 2,040 mg/kg and reached a maximum of 7,000 mg/kg in house dust samples. The estimated variability due to measurement uncertainty was dominated by the sampling process, and the proportion of sampling variance was greater for soil samples, indicating a higher degree of Pb heterogeneity in soil on the given spatial scale of sampling strata. Although the same general spatial trend was observed for both sampling media with decreasing Pb concentration by increasing distance from the ore-processing plant, Pb in dust samples displayed the highest concentrations within a 300-600-m zone from the ore-processing facility. The significant differences which were observed in Pb speciation between the studied media were explained by differences in mineralogical composition of outdoor soil and indoor dust. Lead-enriched Fe and Mn oxides predominated in soil samples while fine galena grains (<10-20 μm diameter) were the major Pb-bearing phase in dust samples. The integrated exposure uptake biokinetic model was used to predict the risk of elevated blood lead levels in children of Stratoni. Model prediction indicated an average probability of 61 % for blood-Pb to exceed 10 μg/dl. The results underline the importance of house dust in risk assessment and highlight the effect of outdoor and indoor conditions on the fate of Pb in the particular environment of Stratoni.

  13. Seasonal concentrations of lead in outdoor and indoor dust and blood of children in Riyadh, Saudi Arabia.

    PubMed

    El-Desoky, Gaber E; Aboul-Soud, Mourad A M; Al-Othman, Zeid A; Habila, Mohamed; Giesy, John P

    2014-06-01

    Because detrimental effects of exposure to lead (Pb) on human health have been observed, we previously investigated concentrations of Pb in water supplies and blood of adult residents of Riyadh, Saudi Arabia. The objectives of the present study were to: (1) examine seasonal rates of deposition of Pb in dust in several areas of Riyadh city, (2) measure concentrations of Pb in both outdoor and indoor dust, (3) compare concentrations of Pb in dust in Riyadh with those reported for other cities, and (4) quantify Pb in blood of children living in Riyadh. Mean, monthly deposition of PB in outdoor dust was 4.7 × 10(1) ± 3.6 tons km(-2), with a mean Pb concentration of 2.4 × 10(2) ± 4.4 × 10(1) μg/g. Mean, monthly deposition of Pb in indoor dust was 2.7 ± 0.70 tons km(-2), with a mean concentration of 2.9 × 10(1) ± 1.5 × 10(1) μg Pb/g. There was a significant (P < 0.01) correlation between concentrations of Pb in outdoor and indoor dust. There was no correlation between concentrations of Pb in indoor dust and that in blood of children of Riyadh, whereas there was a weakly significant (P < 0.05) correlation between concentrations of Pb in outdoor dust and that in blood of children. The mean (±SD) concentration of Pb in blood of children in Riyadh was 5.2 ± 1.7, with a range of 1.7-1.6 × 10(1) μg/dl. Concentrations of Pb in blood of 17.8 % of children in Riyadh were greater than 10 μg/dl, which is the CDC's level of concern.

  14. 42 CFR 84.1146 - Lead fume test for dust, fume, and mist respirators; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Dust, Fume, and Mist; Pesticide; Paint Spray; Powered Air-Purifying High...

  15. Subsonic loads on wings having sharp leading edges and tips

    NASA Technical Reports Server (NTRS)

    Kandil, O. A.; Mook, D. T.; Nayfeh, A. H.

    1976-01-01

    A vortex-lattice method for predicting the aerodynamics of wings having separation at the sharp edges in incompressible flows is extended to compressible subsonic flows using a modified Prandtl-Glauert transformation. Numerical results showing the effect of freestream Mach number on the aerodynamic coefficients are compared with available experimental data for several planforms. It is shown that the proposed method is suitable for predicting the aerodynamic loads on low-aspect wings at moderate angles of attack for high subsonic freestream Mach number. The method is limited to angles of attack up to 12 deg for high subsonic freestream Mach number and to angles of attack up to 20 deg for Mach number not exceeding 0.5.

  16. Lead, arsenic, and polycyclic aromatic hydrocarbons in soil and house dust in the communities surrounding the Sydney, Nova Scotia, tar ponds.

    PubMed Central

    Lambert, Timothy W; Lane, Stephanie

    2004-01-01

    This study evaluated lead, arsenic, and polycyclic aromatic hydrocarbon (PAH) contamination in the residential communities adjacent to the Sydney, Nova Scotia, tar ponds, the area considered Canada's worst contaminated site. The tar pond remediation policy has been limited to the site and some residential properties. We compared background concentrations in 91 soil samples taken 5-20 km from the coke oven site with those in soil samples from the three communities surrounding the tar ponds: Whitney Pier, Ashby, and North End. These surrounding communities were statistically different from background regarding arsenic, lead, and PAHs. Twenty percent of the background soil samples and 95% of the tar pond soil samples were above the Canadian health-risk-based soil guidelines for arsenic (12 ppm), and 5% of the background samples and 80% of the tar pond soil samples were above the Canadian guidelines for lead (140 ppm). Regarding dust lead and arsenic loading, the results provide no evidence that Whitney Pier is significantly different than Ashby and North End. Children in these communities are predicted to have a 1-15% chance of blood lead > 10 microg/dL. The results suggest that lead and arsenic found in the homes originate outside. The lead content of paint in the homes was not evaluated, but consideration of painted wood at the doorway did not confound the results of the study. The results indicate that the residential environment has been adversely affected by PAHs, lead, and arsenic and should be considered for remediation. PMID:14698928

  17. 42 CFR 84.1146 - Lead fume test for dust, fume, and mist respirators; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... RESPIRATORY PROTECTIVE DEVICES Dust, Fume, and Mist; Pesticide; Paint Spray; Powered Air-Purifying High... minutes each at a continuous airflow rate of 32 liters per minute. (b) The relative humidity in the...

  18. 42 CFR 84.1146 - Lead fume test for dust, fume, and mist respirators; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... RESPIRATORY PROTECTIVE DEVICES Dust, Fume, and Mist; Pesticide; Paint Spray; Powered Air-Purifying High... minutes each at a continuous airflow rate of 32 liters per minute. (b) The relative humidity in the...

  19. 42 CFR 84.1146 - Lead fume test for dust, fume, and mist respirators; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... RESPIRATORY PROTECTIVE DEVICES Dust, Fume, and Mist; Pesticide; Paint Spray; Powered Air-Purifying High... minutes each at a continuous airflow rate of 32 liters per minute. (b) The relative humidity in the...

  20. Chemical speciation and bioaccessibility of lead in surface soil and house dust, Lavrion urban area, Attiki, Hellas.

    PubMed

    Demetriades, Alecos; Li, Xiangdong; Ramsey, Michael H; Thornton, Iain

    2010-12-01

    In the Lavrion urban area study, Hellas, a five-step sequential extraction method was applied on samples of 'soil' (n = 224), affected by long-term mining and metallurgical activities, and house dust (n = 127), for the purpose of studying the potential bioaccessibility of lead and other metals to humans. In this paper, the Pb concentrations in soil and house dust samples are discussed, together with those in rocks and children's blood. Lead is mainly associated with the carbonate, Fe-Mn oxides and residual fractions in soil and house dust. Considering the very low pH of gastric fluids (1-3), a high amount of metals, present in soil (810-152,000 mg/kg Pb) and house dust (418-18,600 mg/kg Pb), could be potentially bioaccessible. Consequently, children in the neighbourhoods with a large amount of metallurgical processing wastes have high blood-Pb concentrations (5.98-60.49 μg/100 ml; median 17.83 μg/100 ml; n = 235). It is concluded that the Lavrion urban and sub-urban environment is extremely hazardous to human health, and the Hellenic State authorities should urgently tackle this health-related hazard in order to improve the living conditions of local residents.

  1. The modern atmospheric background dust load: Recognition in Central Asian snowpack, and compositional constraints

    USGS Publications Warehouse

    Hinkley, T.; Pertsiger, F.; Zavjalova, L.

    1997-01-01

    Dusts in strata of snowpack in the Alai-Pamir range, Kirghizstan, Central Asia, have chemical compositions that are in the same restricted range as those of the dusts found in snowpacks at three other locations: central south Greenland, the St. Elias range (Alaska), and coastal Antarctica, where special-type local dust sources certainly cannot dominate. This similarity at the four widely separated sites appears to indicate that there is a modern atmospheric background dust that is the same on a regional, hemispheric, or global scale. The common compositional range is that of average crustal rock, or of moderately ferromagnesian volcanic rock. It is not that of carbonate, nor highly siliciceous rocks. Previously, the existence of an atmospheric background dust has been postulated only on the basis of its particle size distribution, and only from observations in polar regions. The present study partially determines the chemical composition of the background dust, and confirms its existence in snowpack at four localities worldwide, including the center of the earth's largest continent where dusts of local source have considerable influence. U.S. copyright. Published in 1997 by the American Geophysical Union.

  2. Assessment of swine worker exposures to dust and endotoxin during hog load-out and power washing.

    PubMed

    O'Shaughnessy, Patrick; Peters, Thomas; Donham, Kelley; Taylor, Craig; Altmaier, Ralph; Kelly, Kevin

    2012-08-01

    Field measurements of personal and area dust and endotoxin concentrations were obtained while agricultural workers performed two work tasks that have been previously unreported: hog load-out and swine building power washing. Hog load-out involves moving hogs from their pens in finishing buildings into a truck for transport to a meat processor. High pressure power washing is conducted for sanitation purposes after a building has been emptied of hogs to remove surface and floor debris. This debris consists of feed, feces, and hog dander as dust or an encrusted form. The hog load-out process necessarily increases pig activity which is known to increase airborne dust concentrations. An unintended consequence of power washing is that the material covering surfaces is forcibly ejected into the atmosphere, creating the potential for a highly concentrated aerosol exposure to workers. The load-out process resulted in a median personal inhalable mass concentration of 7.14 mg m(-) (3) and median endotoxin concentration of 12 150 endotoxin units (EU) m(-) (3). When converted to an 8-h time-weighted average for a 'total' sampler, one of the 19 samples exceeded a regulatory limit of 15 mg m(-) (3). An impinger was used to sample power washing endotoxin concentrations, which resulted in a median personal concentration of 40 350 EU m(-) (3). These concentrations were among the highest found in the literature for any occupation. With the lack of engineering controls present to reduce airborne contaminant concentrations in swine buildings, either respirator use or a reduction in exposure time is recommended while performing these tasks.

  3. Lead Speciation in House Dust from Canadian Urban Homes Using EXAFS Micro-XRF and Micro-XRD

    SciTech Connect

    L MacLean; S Beauchemin; P Rasmussen

    2011-12-31

    X-ray absorption fine-structure (XAFS) spectroscopy, micro-X-ray fluorescence ({mu}XRF), and micro-X-ray diffraction ({mu}XRD) were used to determine the speciation of Pb in house dust samples from four Canadian urban homes having elevated Pb concentrations (>1000 mg Pb kg{sup -1}). Linear combination fitting of the XAFS data, supported by {mu}XRF and {mu}XRD, shows that Pb is complexed in a variety of molecular environments, associated with both the inorganic and organic fractions of the dust samples. The inorganic species of lead identified were as follows: Pb metal, Pb carbonate, Pb hydroxyl carbonate, Pb oxide, and Pb adsorbed to iron oxyhydroxides. Pb carbonate and/or Pb hydroxyl carbonate occurred in all four dust samples and accounted for 28 to 75% of total Pb. Pb citrate and Pb bound to humate were the organic species identified. The results of this study demonstrate the ability of XAFS to identify Pb speciation in house dust and show the potential to identify Pb sources from new homes versus older homes. Understanding Pb speciation and how it influences bioaccessibility is important for human health risk assessment and risk management decisions which aim to improve indoor environmental health.

  4. Effect of leading-edge load constraints on the design and performance of supersonic wings

    NASA Technical Reports Server (NTRS)

    Darden, C. M.

    1985-01-01

    A theoretical and experimental investigation was conducted to assess the effect of leading-edge load constraints on supersonic wing design and performance. In the effort to delay flow separation and the formation of leading-edge vortices, two constrained, linear-theory optimization approaches were used to limit the loadings on the leading edge of a variable-sweep planform design. Experimental force and moment tests were made on two constrained camber wings, a flat uncambered wing, and an optimum design with no constraints. Results indicate that vortex strength and separation regions were mildest on the severely and moderately constrained wings.

  5. Sequential digestion for measuring leachable and total lead in the same sample of dust or paint chips by ICP-MS.

    PubMed

    Le Bot, Barbara; Arcelin, Claire; Briand, Emmanuel; Glorennec, Philippe

    2011-01-01

    House lead exposure is generally assessed using total lead, except in France, where acid-leachable lead is used for routine regulatory purposes. In order to allow an international comparison of French lead dust contamination, a sequential digestion protocol is developed to determine both leachable and total lead on the same sample with a two-step digestion stage: firstly, hydrochloric acid is added to the sample at 37°C to solubilize leachable lead; then nitric acid is added to an aliquot at 95°C to solubilize residual (i.e., non-leachable) lead. Both sample fractions are analyzed with inductively coupled plasma mass spectrometry (ICP-MS). The sum of the two fractions allows to determine total lead. This new protocol has been tested with wiped dust (n = 111) and paint chip (n = 46) samples collected in houses (n = 16). The leachability of lead ranged from 63 to 100% in dust and from 4 to 100% in paint. These findings confirm the strong variability of lead leachability in houses samples and thus the importance of considering it for lead poisoning prevention. This double determination of leachable and total lead for each wiped dust or paint sample appears to be a reproducible, simple, low-cost protocol and thus a useful tool for international comparison of house dust lead contamination.

  6. The influence of lead content in drinking water, household dust, soil, and paint on blood lead levels of children in Flin Flon, Manitoba and Creighton, Saskatchewan.

    PubMed

    Safruk, Adam M; McGregor, Erin; Whitfield Aslund, Melissa L; Cheung, Paul H; Pinsent, Celine; Jackson, Blair J; Hair, Alan T; Lee, Murray; Sigal, Elliot A

    2017-03-23

    Lead exposure continues to be an important health issue despite the general removal of lead sources in commercial and industrial applications. Low levels of lead exposure have been found to produce adverse neurodevelopmental effects in children with no evidence that a threshold exists for this critical endpoint. Blood lead levels (BLLs) were measured in children (n=118) under the age of 7years in the northern Canadian smelter community of Flin Flon, Manitoba and Creighton, Saskatchewan. An environmental sampling component was included to examine the relationship between lead content in outdoor soil, household dust, tap water, and paint within a given household and the corresponding BLLs in participating children. The geometric mean (GM) BLL for study participants was 1.41μg/dL. Blood lead levels varied slightly by age category with the lowest levels found among the children under age 2 (GM=1.11μg/dL) and the highest levels found among children between 2 and 3years of age (GM=1.98μg/dL). Results from the multivariate modeling indicated that BLLs had a significant positive association with the age of housing (p<0.05), with children living in households constructed prior to 1945 being more likely to have higher levels (p=0.034). Outdoor soil (GM=74.7μg/g), household dust from kitchen floors (GM=1.34μg/ft(2)), and maximum household lead paint were found to be significantly correlated (p<0.05) to BLLs. Although a statistically significant association between concentrations of lead in these household media and the corresponding BLLs exists, the variability in BLLs was poorly explained by these factors alone (r(2)=0.07, 0.12 and 0.06 for soil, household dust, and paint, respectively). Lead concentrations in flushed (GM=0.89μg/L) and stagnant (GM=2.07μg/L and 1.18μg/L) tap water samples were not significantly correlated (p>0.05) to BLLs.

  7. High perceptual load leads to both reduced gain and broader orientation tuning

    PubMed Central

    Stolte, Moritz; Bahrami, Bahador; Lavie, Nilli

    2014-01-01

    Due to its limited capacity, visual perception depends on the allocation of attention. The resultant phenomena of inattentional blindness, accompanied by reduced sensory visual cortex response to unattended stimuli in conditions of high perceptual load in the attended task, are now well established (Lavie, 2005; Lavie, 2010, for reviews). However, the underlying mechanisms for these effects remain to be elucidated. Specifically, is reduced perceptual processing under high perceptual load a result of reduced sensory signal gain, broader tuning, or both? We examined this question with psychophysical measures of orientation tuning under different levels of perceptual load in the task performed. Our results show that increased perceptual load leads to both reduced sensory signal and broadening of tuning. These results clarify the effects of attention on elementary visual perception and suggest that high perceptual load is critical for attentional effects on sensory tuning. PMID:24610952

  8. Assessing the Effects of Dust Loading of Snow on Regional Hydroclimatology Using an Improved Regional Climate Model

    NASA Astrophysics Data System (ADS)

    Oaida, C. M.; Xue, Y.; Painter, T.; Flanner, M. G.; De Sales, F.

    2012-12-01

    Radiative processes play an important role on both global and regional scales. This study focuses on their effects over snow-covered surfaces due to dust loading. Studies have shown that dust emissions from the Colorado Plateau have increased 5-7 fold in the last century and a half due to grazing and agricultural practices, which decreases snow albedo and enhances solar radiation absorption. In an offline study, Painter et al. (2007) have shown that snow cover was shortened by 18 to 35 days due to dust radiative forcing in snow in the San Juan Mountains, Colorado, USA. Our present study will quantitatively assess dust's influence on radiative forcing and runoff timing in mountain snow packs using a physically comprehensive regional climate model. For this study, we employ NCAR's WRF ARW model, which is coupled with a land surface model, Simplified Simple Biosphere version 3 (SSiB3). We have modified the original WRF-SSiB3 framework to include a snow-radiative transfer model, Snow, Ice, and Aerosol Radiative (SNICAR) model. SNICAR considers the effects of snow grain size and aerosol on snow albedo evolution. Snow grain size and growth is important in snow albedo feedbacks, especially when aerosols in snow are considered, because larger snow grains decrease snow albedo, and in the presence of dust, grain growth rates increase, decreasing snow reflectance even further than if the snow was pure. In the original WRF-SSiB3, albedo was empirically adjusted during snow melt. Implementing SNICAR allows us to have a more physically based process to represent changes in albedo due to snow metamorphism as well as those due to impurities in snow, which makes the regional climate model capable of realistically simulating radiative forcing on snow covered areas with aerosol loading. The model was further modified to account for the presence of aerosols in snow in terms of the distribution of these impurities as well as their scavenging by melt water throughout the snow layers We

  9. Lead isotopes combined with a sequential extraction procedure for source apportionment in the dry deposition of Asian dust and non-Asian dust.

    PubMed

    Lee, Pyeong-Koo; Yu, Soonyoung

    2016-03-01

    Lead isotopic compositions were determined in leachates that were generated using sequential extractions of dry deposition samples of Asian dust (AD) and non-Asian dust (NAD) and Chinese desert soils, and used to apportion Pb sources. Results showed significant differences in (206)Pb/(207)Pb and (206)Pb/(204)Pb isotopic compositions in non-residual fractions between the dry deposition samples and the Chinese desert soils while (206)Pb/(207)Pb and (206)Pb/(204)Pb isotopic compositions in residual fraction of the dry deposition of AD and NAD were similar to the mean (206)Pb/(207)Pb and (206)Pb/(204)Pb in residual fraction of the Alashan Plateau soil. These results indicate that the geogenic materials of the dry deposition of AD and NAD were largely influenced by the Alashan Plateau soil, while the secondary sources of the dry deposition were different from those of the Chinese desert soils. In particular, the lead isotopic compositions in non-residual fractions of the dry deposition were homogenous, which implies that the non-residual four fractions (F1 to F4) shared the primary anthropogenic origin. (206)Pb/(207)Pb values and the predominant wind directions in the study area suggested that airborne particulates of heavily industrialized Chinese cities were one of the main Pb sources. Source apportionment calculations showed that the average proportion of anthropogenic Pb in the dry deposition of AD and NAD was 87% and 95% respectively in total Pb extraction, 92% and 97% in non-residual fractions, 15% and 49% in residual fraction. Approximately 81% and 80% of the anthropogenic Pb was contributed by coal combustion in China in the dry deposition of AD and NAD respectively while the remainder was derived from industrial Pb contamination. The research result proposes that sequential extractions with Pb isotope analysis are a useful tool for the discrimination of anthropogenic and geogenic origins in highly contaminated AD and NAD. Copyright © 2015 Elsevier Ltd. All

  10. The Effect of the Hemochromatosis (HFE) Genotype on Lead Load and Iron Metabolism among Lead Smelter Workers

    PubMed Central

    Fan, Guangqin; Du, Guihua; Li, Huijun; Lin, Fen; Sun, Ziyong; Yang, Wei; Feng, Chang; Zhu, Gaochun; Li, Yanshu; Chen, Ying; Jiao, Huan; Zhou, Fankun

    2014-01-01

    Background Both an excess of toxic lead (Pb) and an essential iron disorder have been implicated in many diseases and public health problems. Iron metabolism genes, such as the hemochromatosis (HFE) gene, have been reported to be modifiers for lead absorption and storage. However, the HFE gene studies among the Asian population with occupationally high lead exposure are lacking. Objectives To explore the modifying effects of the HFE genotype (wild-type, H63D variant and C282Y variant) on the Pb load and iron metabolism among Asian Pb-workers with high occupational exposure. Methods Seven hundred and seventy-one employees from a lead smelter manufacturing company were tested to determine their Pb intoxication parameters, iron metabolic indexes and identify the HFE genotype. Descriptive and multivariate analyses were conducted. Results Forty-five H63D variant carriers and no C282Y variant carrier were found among the 771 subjects. Compared with subjects with the wild-type genotype, H63D variant carriers had higher blood lead levels, even after controlling for factors such as age, sex, marriage, education, smoking and lead exposure levels. Multivariate analyses also showed that the H63D genotype modifies the associations between the blood lead levels and the body iron burden/transferrin. Conclusions No C282Y variant was found in this Asian population. The H63D genotype modified the association between the lead and iron metabolism such that increased blood lead is associated with a higher body iron content or a lower transferrin in the H63D variant. It is indicated that H63D variant carriers may be a potentially highly vulnerable sub-population if they are exposed to high lead levels occupationally. PMID:24988074

  11. Modified natural clinoptilolite detoxifies small mammal's organism loaded with lead I. Lead disposition and kinetic model for lead bioaccumulation.

    PubMed

    Beltcheva, Michaela; Metcheva, Roumiana; Popov, Nikolay; Teodorova, Svetla E; Heredia-Rojas, J Antonio; Rodríguez-de la Fuente, Abraham O; Rodríguez-Flores, Laura E; Topashka-Ancheva, Margarita

    2012-06-01

    Zeolites, especially clinoptilolites, have wide application in removing heavy metals from different solutions and wastewater. The detoxification capacity of the clinoptilolite sorbent KLS-10-MA, a modified natural Bulgarian zeolite, applied as a food supplement in conditions of an ecotoxicological experiment with conventional food and lead was demonstrated for the first time. Laboratory mice, inbred imprinting control region strain, were used in a 90-day ecotoxicological experiment. Animals were divided into four experimental groups. Lead bioaccumulations in exposed and non-supplemented/supplemented with KLS-10-MA animals were compared. As additional control, healthy animals non-exposed to Pb were fed with conventional forage mixed with 12.5% KLS-10-MA. The dietary inclusion of the sorbent reduced Pb concentrations in exposed and supplemented mice by 84%, 89%, 91%, 77%, and 88% in carcass, liver, kidneys, bones, and feces, respectively. A mathematical model was proposed to outline the common trends of bone Pb bioaccumulation in exposed and non-supplemented/supplemented animals. Characteristic parameters of the kinetics of Pb concentrations were determined. Based on the model, the coefficient of absorption of Pb by gastrointestinal mucosa in the supplemented mice was found-η = 3.53% (versus η = 15% in non-supplemented ones). The present study clearly indicates that there is a realistic perspective to create a new drug based on modified natural clinoptilolites in cases of chronic heavy metal intoxication, without negatively affecting the environment.

  12. Road Dust Lead (Pb) in Two Neighborhoods of Urban Atlanta, (GA, USA)

    PubMed Central

    Deocampo, Daniel M.; Reed, Jack; Kalenuik, Alexander P.

    2012-01-01

    Road dust continues to be a major potential reservoir of Pb in the urban environment, and an important potential component of child Pb exposure. This study presents ICP-AES analyses of metals in 72 samples of road dust (<250 µm) collected in the urban core of Atlanta, Georgia. In the Downtown area, median Pb concentrations are ~63 mg/kg Pb, with high values of 278 mg/kg. For comparison, median Pb values in a nearby residential neighborhood (also in the urban core) were ~93 mg/kg, with a high of 972 mg/kg. Geospatial variability is high, with significant variation observed over tens to hundreds of meters. Spearman Rank Correlation tests suggest that Pb and other metals (Cu, Ni, V, Zn) are associated with iron and manganese oxide phases in the residential area, as reported in other cities. However, Pb in the Downtown area is not correlated with the others, suggesting a difference in source or transport history. Given these complexities and the expected differences between road dust and soil Pb, future efforts to assess exposure risk should therefore be based on spatially distributed sampling at very high spatial resolution. PMID:22829787

  13. [Magnetic Response of Dust-loaded Leaves in Parks of Shanghai to Atmospheric Heavy Metal Pollution].

    PubMed

    Liu, Fei; Chu, Hui-min; Zheng, Xiang-min

    2015-12-01

    To reveal the magnetic response to the atmospheric heavy metal pollution in leaves along urban parks, Camphor leaf samples, widely distributed at urban parks, were collected along the year leading wind direction of Shanghai, by setting two vertical and horizontal sections, using rock magnetic properties and heavy metal contents analysis. The results showed that the magnetic minerals of samples were predominated by ferromagnetic minerals, and both the concentration and grain size of magnetite particles gradually decreased with the winter monsoon direction from the main industrial district. A rigorous cleaning of leaves using ultrasonic agitator washer could remove about 63%-90% of low-field susceptibility values of the leaves, and this strongly indicated that the intensity of magnetic signal was mainly controlled by the PMs accumulated on the leaves surfaces. Moreover, there was a significant linear relationship between heavy metals contents (Fe, Mn, Zn, Cu, Cr, V and Pb) and magnetic parameters (0.442 ≤ R ≤ 0.799, P < 0.05), which suggested that magnetic parameters of urban park leaves could be used as a proxy for atmospheric heavy metal pollution. The results of multivariate statistical analysis showed that the content of magnetic minerals and heavy metal indust-loaded tree leaves was affected by associated pollution of industry and traffic.

  14. Inattentional Deafness: Visual Load Leads to Time-Specific Suppression of Auditory Evoked Responses

    PubMed Central

    Molloy, Katharine; Griffiths, Timothy D.; Lavie, Nilli

    2015-01-01

    Due to capacity limits on perception, conditions of high perceptual load lead to reduced processing of unattended stimuli (Lavie et al., 2014). Accumulating work demonstrates the effects of visual perceptual load on visual cortex responses, but the effects on auditory processing remain poorly understood. Here we establish the neural mechanisms underlying “inattentional deafness”—the failure to perceive auditory stimuli under high visual perceptual load. Participants performed a visual search task of low (target dissimilar to nontarget items) or high (target similar to nontarget items) load. On a random subset (50%) of trials, irrelevant tones were presented concurrently with the visual stimuli. Brain activity was recorded with magnetoencephalography, and time-locked responses to the visual search array and to the incidental presence of unattended tones were assessed. High, compared to low, perceptual load led to increased early visual evoked responses (within 100 ms from onset). This was accompanied by reduced early (∼100 ms from tone onset) auditory evoked activity in superior temporal sulcus and posterior middle temporal gyrus. A later suppression of the P3 “awareness” response to the tones was also observed under high load. A behavioral experiment revealed reduced tone detection sensitivity under high visual load, indicating that the reduction in neural responses was indeed associated with reduced awareness of the sounds. These findings support a neural account of shared audiovisual resources, which, when depleted under load, leads to failures of sensory perception and awareness. SIGNIFICANCE STATEMENT The present work clarifies the neural underpinning of inattentional deafness under high visual load. The findings of near-simultaneous load effects on both visual and auditory evoked responses suggest shared audiovisual processing capacity. Temporary depletion of shared capacity in perceptually demanding visual tasks leads to a momentary reduction in

  15. Biosorption of lead by filamentous fungal biomass-loaded TiO2 nanoparticles.

    PubMed

    Bakircioglu, Yasemin; Bakircioglu, Dilek; Akman, Suleyman

    2010-06-15

    In this study filamentous fungal biomass-loaded TiO(2) nanoparticles were used for the biosorption of lead(II) ions by flow-injection system coupled to flame atomic absorption spectrometry. The effects of pH, sample volume, loading and elution flow rates, eluent type and volume on the recovery of lead were investigated. Lead ions were sorbed on a biosorbent minicolumn at pH 4.0 followed by an elution step using 288 microL of 1.0 mol/L hydrochloric acid solution. The limit of detection was 0.78 microg/L. The validation of the described procedure was performed by the analysis of certified reference material (NRC-CNRC NASS-5 seawater). Finally, the presented biosorption procedure was applied to the determination of lead in tap water and seawater samples.

  16. A photochemical model of the dust-loaded ionosphere of Mars

    NASA Astrophysics Data System (ADS)

    Cardnell, S.; Witasse, O.; Molina-Cuberos, G. J.; Michael, M.; Tripathi, S. N.; Déprez, G.; Montmessin, F.; O'Brien, K.

    2016-11-01

    The ionization of the lower Martian atmosphere and the presence of charged species are fundamental in the understanding of atmospheric electricity phenomena, such as electric discharges, large-scale electric currents, and Schumann resonances. The present photochemical model of the lower ionosphere of Mars (0-70 km) is developed to compute the concentration of the most abundant charged species (cluster ions, electrons, and charged aerosols) and electric conductivity, at the landing site and epoch of the ExoMars 2016 mission. The main sources of ionization are galactic cosmic rays (during daytime as well as nighttime) and photoionization of aerosols due to solar UV radiation during daytime. Ion and electron attachment to aerosols is another major source of aerosol charging. The steady state concentration of charged species is computed by solving their respective balance equations (also known as continuity equations), which include the source and sink terms of their photochemical reactions. Since the amount of suspended dust can vary considerably and it has an important effect on atmospheric properties, several dust scenarios, in addition to the day-night variations, are considered to characterize the variability of the concentration of charged species. It has been found that during daytime, aerosols tend to become positively charged due to electron photoemission and, during nighttime, tend to charge negatively due to electron attachment. The most dominant day-night variability in ion and electron concentration occurs when the amount of suspended dust is the largest. The electric conductivity has been found to vary in the 10-13-10-7 S/m range, depending on the altitude, dust scenario, and local time.

  17. Environmental and childhood lead contamination in the proximity of boat-repair yards in southern Thailand--I: pattern and factors related to soil and household dust lead levels.

    PubMed

    Maharachpong, Nipa; Geater, Alan; Chongsuvivatwong, Virasakdi

    2006-07-01

    High blood lead levels have recently been documented in schoolchildren living in communities adjacent to boat-repair yards in southern Thailand. In this study, the spatial pattern of lead contamination of soil and household dust in an area surrounding several boat-repair yards is described, and household factors associated with elevated dust lead are identified. A cross-sectional spatial study was conducted in a coastal residential area within a distance of 2 km from three major boat-repair yards situated on the east coast of peninsular Thailand. Household dust specimens were collected from an undisturbed position in the residences of children, aged 4-14 years, sampled randomly from all children living in the study area. Soil specimens were obtained from the interstices of a square grid, 70 x 70 m2, superimposed on the area. Geographic coordinates of residence and soil sampling positions were recorded and semivariograms and kriging used to contour the spatial distribution of lead in dust and soil. Environmental lead levels were also modeled in terms of direction and minimum distance from a boat-repair yard and, for household dust lead content, in terms of household variables, including occupation of household members in boat-repair work, type of house construction, and general cleanliness. Household dust and soil lead content ranged from 10 to 3025 mg/kg and from 1 to 7700 mg/kg, respectively. The distribution of soil lead peaked at the location of the boat-repair yards, but outside the yards the distribution was generally below 400 mg/kg and irregular. About 24% of household dust lead specimens were equal to or above 400 mg/kg, but showed significant decrease with increasing distance from the boat-repair yards, at rates of between 7% and 14% per 100 m. In houses where a family member was a worker in one of the major boatyards and in houses where occasional repair of small boats was undertaken, household dust lead levels were significantly elevated, by 65% (95% CI

  18. Removal of lead by using Raschig rings manufactured with mixture of cement kiln dust, zeolite and bentonite.

    PubMed

    Salem, A; Afshin, H; Behsaz, H

    2012-07-15

    The present investigation is a follow-up of study on manufacturing Raschig ring for removal of lead from aqueous solution. The mixtures were formulated using cement kiln dust, zeolite, and bentonite, normally used as natural adsorbents in the industrial scale, according to mixture design algorithm and response surface method. The pastes were prepared by addition of 28.0wt.% de-ionized water, containing 0.1wt.% carboxymethyl cellulose, with mixed powders. The adsorbents were fabricated by extrusion of the pastes in Raschig ring form and calcination at 500°C after drying in oven. The effects of starting materials on the mechanical behavior of rings were studied from view point of mixture design algorithm to optimize the adsorbent composition. This method demonstrated to yield valuable information on the effects of used materials on mechanical characteristics. The study concluded that the strength, reliability and sorption capacity of ring can be simultaneously optimized by the addition of 47.5wt.% cement kiln dust, 32.5wt.% zeolite, and 20.0wt.% bentonite. In the next part of work, the sorption kinetics was investigated. The kinetic study indicated that the modified model can successfully correlate the sorption data. The equilibrium result showed the possibility of lead immobilization by fabricated rings. Copyright © 2012. Published by Elsevier B.V.

  19. Large lead/acid batteries for frequency regulation, load levelling and solar power applications

    NASA Astrophysics Data System (ADS)

    Wagner, R.

    Lead/acid batteries are suitable for a multitude of utility applications. This paper presents some examples where large lead/acid batteries have been used for frequency regulation, load levelling and solar power applications. The operational experiences are given together with a discussion about the design and technical specialities of these batteries. In 1986, a 17 MW/14 MWh battery was installed at BEWAG in Berlin which, at that time, was the largest lead/acid battery in the world. Designed to strengthen Berlin's 'island' system, it was used since the beginning of 1987 for frequency regulation and spinning reserve. In December 1993, when Berlin was connected to the electricity grid, frequency regulation was no longer required but the battery was still used for spinning reserve. For many years, the industrial battery plant of Hagen in Soest has used a large lead/acid battery for load levelling. The experience gained during more than ten years shows that load levelling and peak shaving can be a marked benefit for customers and utilities with regard to reducing their peak demand. In the summer of 1992, a 216 V and 2200 Ah lead/acid battery with positive tubular plates and gelled electrolyte was installed at a solar power plant in Flanitzhutte, a small village in the south of Germany which is not connected to the electricity grid. A report is given of the first years of use and includes a discussion about the best charge strategy for such gel batteries when used for solar power applications.

  20. Improving Quality and Performance of Leads Loaded with Composition A-5

    DTIC Science & Technology

    1984-03-01

    Composition A-5 sensitivity versus stearic acid and HMX content 8 ř 3 Sieve analysis of the RDX used to produce Composition A-5 9 -A 4 Lot numbers of...cm 3 . The leads were loaded at LSAAP on a 41 station rotary press which is typically used for high volume lead production. Lot numbers assigned to...sample of this lot was made with Class 5 RDX (97% minimum through a No. 325 U.S. Standard Sieve). .9 -’ .’ Table 4. Lot numbers of leads Material: Comp

  1. Lead, mercury, cadmium, chromium, nickel, copper, zinc, calcium, iron, manganese and chromium (VI) levels in Nigeria and United States of America cement dust.

    PubMed

    Ogunbileje, J O; Sadagoparamanujam, V-M; Anetor, J I; Farombi, E O; Akinosun, O M; Okorodudu, A O

    2013-03-01

    This study was aimed at investigating the relative abundance of heavy metals in cement dust from different cement dust factories in order to predict their possible roles in the severity of cement dust toxicity. The concentrations of total mercury (Hg), copper (Cu), chromium (Cr), cadmium (Cd), nickel (Ni), manganese (Mn), lead (Pb), iron (Fe) and chromium (VI) (Cr (VI)) levels in cement dust and clinker samples from Nigeria and cement dust sample from the United States of America (USA) were determined using graphite furnace atomic absorption (GFAAS), while Zn and Ca were measured by flame atomic absorption spectrophotometry (FAAS), and Cr (VI) by colorimetric method. Total Cu, Ni and Mn were significantly higher in cement dust sample from USA (p<0.05), also, both total Cr and Cr (VI) were 5.4-26 folds higher in USA cement dust compared with Nigeria cement dust or clinker (p<0.001). Total Cd was higher in both Nigeria cement dust and clinker (p<0.05 and p<0.001), respectively. Mercury was more in both Nigeria cement dust and clinker (p<0.05), while Pb was only significantly higher in clinker from Nigeria (p<0.001). These results show that cement dust contain mixture of metals that are known human carcinogens and also have been implicated in other debilitating health conditions. Additionally, it revealed that metal content concentrations are factory dependent. This study appears to indicate the need for additional human studies relating the toxicity of these metals and their health impacts on cement factory workers. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. The influence of leading-edge load alleviation on supersonic wing design

    NASA Technical Reports Server (NTRS)

    Darden, C. M.

    1984-01-01

    A theoretical and experimental program to assess the effect of leading-edge load constraints on wing design and performance was conducted. For a planform characterized by a highly swept leading edge on the inboard region, linear theory was used to design camber surfaces which produced minimum drag-due-to-lift at the design lift coefficient of 0.08 and a design Mach number of 2.4. In an effort to delay the formation of leading edge vortices which often occur on highly swept wings, two approaches were used in the design criteria to limit the loadings on the leading edge. One wing was constrained to have the normal Mach number less than one everywhere along the leading edge and the second wing was constrained to have a pressure coefficient of zero on the leading edge. Force tests were run on the two constrained wings, on a flat reference wing and on an optimized wing with no leading edge constraints. All wings had identical planforms and thicknesses and were tested over a range of Mach numbers from 1.8 to 2.8 and a range in angles of attack from -5 deg to 8 deg. A comparison of the experimental performance of these four models is shown. Correlations of these results with theoretical predictions and flow visualization photographs are also included.

  3. Non-fibrous dust load and smoking in dental technicians: a study using bronchoalveolar lavage.

    PubMed Central

    Bernstein, M; Pairon, J C; Morabia, A; Gaudichet, A; Janson, X; Brochard, P

    1994-01-01

    A study was conducted with transmission electron microscopy to find whether bronchoalveolar lavage could be used to identify subjects with occupational exposure to mineral particles. Non-fibrous mineral particles in bronchoalveolar lavage (BAL) fluid from 46 dental technicians and 41 white collar controls with lung diseases but free from occupational exposure to dusts were analysed. The total particle concentration in BAL fluid was significantly higher in dental technicians than in controls (12.18 x 10(5) particles/ml of BAL fluid, v 2.03 x 10(5) particles/ml, p < 0.001). Dental technicians had significantly more crystalline silica, aluminium, and alloys containing nickel and chromium. There was a non-significant twofold increase of total particle concentration in the lungs of dental technicians who were smokers compared with non-smokers. The results strongly support the use of BAL fluid analysis to assess dust accumulation in workers in heavily exposed occupations such as dental technicians. This is a valid method to evaluate occupational exposure to non-fibrous mineral particles, and may be useful to determine the occupational aetiology of some respiratory diseases. PMID:8124458

  4. Estimation of the dust production rate from the tungsten armour after repetitive ELM-like heat loads

    NASA Astrophysics Data System (ADS)

    Pestchanyi, S.; Garkusha, I.; Makhlaj, V.; Landman, I.

    2011-12-01

    Experimental simulations for the erosion rate of tungsten targets under ITER edge-localized mode (ELM)-like surface heat loads of 0.75 MJ m-2 causing surface melting and of 0.45 MJ m-2 without melting have been performed in the QSPA-Kh50 plasma accelerator. Analytical considerations allow us to conclude that for both energy deposition values the erosion mechanism is solid dust ejection during surface cracking under the action of thermo-stress. Tungsten influx into the ITER containment of NW~5×1018 W per medium size ELM of 0.75 MJ m-2 and 0.25 ms time duration has been estimated. The radiation cooling power of Prad=150-300 MW due to such influx of tungsten is intolerable: it should cool the ITER core to 1 keV within a few seconds.

  5. Detoxification of a highly toxic lead-loaded industrial solid waste by stabilization using apatites.

    PubMed

    Ioannidis, T A; Zouboulis, A I

    2003-02-28

    Apatites are known for their properties to immobilize lead contained in aqueous solutions or contaminated soils. In this study, apatites were examined as stabilization additives for lead-loaded industrial solid toxic wastes. The specific waste was the residue, obtained after thermal treatment of sludges (incineration), which was derived from tetraethyl lead fuel storage tanks. It was found to contain around 30 wt.% lead and 33 wt.% iron. Standard leaching tests (according to DIN 38414 S-4) were applied for the determination of leachability of metals from the ash and, thus, of chemical toxicity; the proposed leaching tests examined both initial and stabilized products in order to evaluate the effectiveness of the applied additives. The results obtained demonstrate the fact that lead concentrations in leachates, after the application of the proposed leaching tests using apatites as additives and with a ratio of 50% solid waste-50 wt.% apatite, could be reduced to the range of 1mg/l.

  6. Metal enrichment and lead isotope analysis for source apportionment in the urban dust and rural surface soil.

    PubMed

    Yu, Yang; Li, Yingxia; Li, Ben; Shen, Zhenyao; Stenstrom, Michael K

    2016-09-01

    To understand the metal accumulation in the environment and identify its sources, 29 different metal contents and lead (Pb) isotope ratios were determined for 40 urban dust samples, 36 surface soil samples, and one river sediment sample collected in the municipality of Beijing, China. Results showed that cadmium, copper (Cu), mercury, Pb, antimony (Sb), and zinc demonstrated to be the typical urban contaminants and mostly influenced by the adjacent human activities with higher content to background ratios and SD values. Among the 29 metal elements investigated, Cu and Sb were found to be the most distinct elements that were highly affected by the developing level and congestion status of the cities with much higher contents in dust in more developed and congested cities. There was a relatively wider range of Pb isotope ratios of country surface soil than those of urban dust. The results of source identification based on Pb isotope ratios showed that coal combustion was the first largest Pb source and vehicle exhaust was the second largest source. The sum of them accounted for 74.6% mass proportion of overall Pb pollution on average. The surface soil sample collected at an iron mine had the highest (204)Pb/(206)Pb, (207)Pb/(206)Pb, and (208)Pb/(206)Pb ratios indicating ore had much higher ratios than other sources. The fine particle subsamples had higher (204)Pb/(206)Pb, (207)Pb/(206)Pb, and (208)Pb/(206)Pb ratios than the coarse particle subsamples indicating more anthropogenic sources of coal combustion and vehicle exhaust for fine particles and more background influence for coarse particles. These results help with pinpointing the major Pb sources and applying suitable measures for the target sources.

  7. Model of the dust-loaded ionospheres of Mars and Titan

    NASA Astrophysics Data System (ADS)

    Witasse, Olivier; Cardnell, Sandy; Molina-Cuberos, Gregorio; Michael, Mary; Tripathi, Sachi; Deprez, Gregoire; Montmessin, Franck; O'Brien, Keran

    2016-10-01

    The ionization of lower atmospheres of celestial bodies and the presence of charged species are fundamental in the understanding of atmospheric electricity phenomena, such as electric discharges, large scale electric currents and Schumann resonances. On January 14, 2005, the Huygens Probe measured the electric conductivity of Titan's atmosphere from 140 km down to the surface. Micro-ARES, the electric field and conductivity sensor on board the ExoMars 2016 Schiaparelli lander, will conduct the very first measurement and characterization of Martian atmospheric electricity. The landing is scheduled for October 19, 2016 and the measurements will be performed over 2-4 sols.The present photochemical model is developed to compute the concentration of the most abundant charged species (cluster-ions, electrons and charged aerosols) and electric conductivity in the lower atmospheres of Mars (0-70 km) and Titan (0-145 km). For both cases, the main source of ionization is galactic cosmic rays. In addition, during daytime, photoionization of aerosols due to solar UV radiation is important at Mars. Ion and electron attachment to aerosols is another major source of aerosol charging, which can vary between -50 and +200 elementary charges for Mars and -55 and -25 for Titan. The steady state concentration of charged species is computed by solving the respective balance equations, which include the source and sink terms of the photochemical reactions. Since the amount of suspended dust in the Martian atmosphere can vary considerably and it has an important effect on the atmospheric properties, several dust scenarios, in addition to the day-night variations, are considered to characterize the variability of the concentration of charged species.The agreement between with the results of the model for Titan and the Huygens data suggests an improvement with respect to previous models. This gives confidence in the results of the model for Mars, which characterize the predicted electric

  8. Effect of lead speciation on its oral bioaccessibility in surface dust and soil of electronic-wastes recycling sites.

    PubMed

    Fujimori, Takashi; Taniguchi, Masaya; Agusa, Tetsuro; Shiota, Kenji; Takaoka, Masaki; Yoshida, Aya; Terazono, Atsushi; Ballesteros, Florencio C; Takigami, Hidetaka

    2018-01-05

    We measured bioaccessible lead (Pb) in simulated gastrointestinal fluids containing Pb-contaminated soil or dust from electronic waste (e-waste) recycling sites to assess the risk of Pb ingestion. The physiologically based extraction test (PBET) was used as in vitro bioaccessibility assay. Pb speciation was determined using X-ray absorption spectroscopy. The total Pb concentrations in dusts (n=8) and soils (n=4) were in the range of 1630-131,000 and 239-7800mg/kg, respectively. Metallic Pb, a common component of e-waste, was ubiquitous in the samples. We also found Pb adsorbed onto goethite and as oxides and carbonate, implying soil mixing and weathering influences. Pb phosphate and organic species were only found in the soil samples, suggesting that formation was soil-specific. We identified other Pb compounds in several samples, including Pb silicate, Pb chromate, and Pb(II) hydrogen phosphate. A correlation analysis indicated that metallic Pb decreased bioaccessibility in the stomach, while a Pb speciation analysis revealed a low bioaccessibility for Pb phosphates and high bioaccessibility for organic Pb species. The health risk based on bioaccessible Pb was estimated to be much lower than that of total Pb due to the lower concentrations. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Interactive Soil Dust Aerosol Model in the GISS GCM. Part 1; Sensitivity of the Soil Dust Cycle to Radiative Properties of Soil Dust Aerosols

    NASA Technical Reports Server (NTRS)

    Perlwitz, Jan; Tegen, Ina; Miller, Ron L.

    2000-01-01

    The sensitivity of the soil dust aerosol cycle to the radiative forcing by soil dust aerosols is studied. Four experiments with the NASA/GISS atmospheric general circulation model, which includes a soil dust aerosol model, are compared, all using a prescribed climatological sea surface temperature as lower boundary condition. In one experiment, dust is included as dynamic tracer only (without interacting with radiation), whereas dust interacts with radiation in the other simulations. Although the single scattering albedo of dust particles is prescribed to be globally uniform in the experiments with radiatively active dust, a different single scattering albedo is used in those experiments to estimate whether regional variations in dust optical properties, corresponding to variations in mineralogical composition among different source regions, are important for the soil dust cycle and the climate state. On a global scale, the radiative forcing by dust generally causes a reduction in the atmospheric dust load corresponding to a decreased dust source flux. That is, there is a negative feedback in the climate system due to the radiative effect of dust. The dust source flux and its changes were analyzed in more detail for the main dust source regions. This analysis shows that the reduction varies both with the season and with the single scattering albedo of the dust particles. By examining the correlation with the surface wind, it was found that the dust emission from the Saharan/Sahelian source region and from the Arabian peninsula, along with the sensitivity of the emission to the single scattering albedo of dust particles, are related to large scale circulation patterns, in particular to the trade winds during Northern Hemisphere winter and to the Indian monsoon circulation during summer. In the other regions, such relations to the large scale circulation were not found. There, the dependence of dust deflation to radiative forcing by dust particles is probably

  10. Effects of Nose Radius and Aerodynamic Loading on Leading Edge Receptivity

    NASA Technical Reports Server (NTRS)

    Hammerton, P. W.; Kerschen, E. J.

    1998-01-01

    An analysis is presented of the effects of airfoil thickness and mean aerodynamic loading on boundary-layer receptivity in the leading-edge region. The case of acoustic free-stream disturbances, incident on a thin cambered airfoil with a parabolic leading edge in a low Mach number flow, is considered. An asymptotic analysis based on large Reynolds number is developed, supplemented by numerical results. The airfoil thickness distribution enters the theory through a Strouhal number based on the nose radius of the airfoil, S = (omega)tau(sub n)/U, where omega is the frequency of the acoustic wave and U is the mean flow speed. The influence of mean aerodynamic loading enters through an effective angle-of-attack parameter ti, related to flow around the leading edge from the lower surface to the upper. The variation of the receptivity level is analyzed as a function of S, mu, and characteristics of the free-stream acoustic wave. For an unloaded leading edge, a finite nose radius dramatically reduces the receptivity level compared to that for a flat plate, the amplitude of the instability waves in the boundary layer being decreased by an order of magnitude when S = 0.3. Modest levels of aerodynamic loading are found to further decrease the receptivity level for the upper surface of the airfoil, while an increase in receptivity level occurs for the lower surface. For larger angles of attack close to the critical angle for boundary layer separation, a local rise in the receptivity level occurs for the upper surface, while for the lower surface the receptivity decreases. The effects of aerodynamic loading are more pronounced at larger values of S. Oblique acoustic waves produce much higher receptivity levels than acoustic waves propagating downstream parallel to the airfoil chord.

  11. Lead loading of urban roadways by motor vehicle wheel weights: some Australian observations using novel methodology.

    PubMed

    Frazer, Eric J; van der Touw, John

    2014-01-15

    Wheel weights fall off motor vehicles, accumulate on urban roadways and contribute to lead loading of the environment. The objective of the present research was to determine mass distribution, deposition rate, residence time, mass loss, and lead loading per annum on roadways in Melbourne, the capital city of Victoria, Australia. We surveyed wheel weights on 3-3.5 km segments of local/secondary roads over five years, and an 8.2 km segment of a primary arterial road over five month periods. The approach to steady state was also monitored using Global Positioning System (GPS) tracking of the position of weights deposited by motor vehicles. The average deposition rate and residence time were estimated using Poisson modeling of the observations. The distribution of wheel weight masses generally reflected the quantities supplied to the new car and tire market, with the 10 to 30 g range making up almost 70% of the total observed. The number of wheel weights observed was correlated with the commercial content of the route, but residence times depended on the location. The weighted average mass loss of wheel weights deposited on a primary arterial road was 5.9% and the average residence time was 38.1 days. Lead loading on Melbourne roadways was estimated to be 10.9 tonnes/year with 10.3 tonnes/year as intact pieces and 0.6 tonne/year as particulates (or dissolved).

  12. Dust Studies in DIII-D Tokamak

    SciTech Connect

    Rudakov, D L; West, W P; Groth, M; Yu, J H; Boedo, J A; Bray, B D; Brooks, N H; Fenstermacher, M E; Hollmann, E M; Hyatt, A W; Krasheninnikov, S I; Lasnier, C J; Moyer, R A; Pigarov, A Y; Smirnov, R; Solomon, W M; Wong, C C

    2008-04-15

    Studies of submicron dust using Mie scattering from Nd:YAG lasers and video data of micron to sub-millimeter sized dust on DIII-D tokamak have provided the first data of dust sources and transport during tokamak discharges. During normal operation on DIII-D dust observation rates are low, a few events per discharge or less. The net carbon content of the dust corresponds to a carbon atom density a few orders of magnitude below the core impurity density. Statistical analysis of Mie data collected over months of operation reveal correlation of increased dust rate with increased heating power and impulsive wall loading due to edge localized modes (ELMs) and disruptions. Generation of significant amounts of dust by disruptions is confirmed by the camera data. However, dust production by disruptions alone is insufficient to account for estimated in-vessel dust inventory in DIII-D. After an extended entry vent, thousands of dust particles are observed by cameras in the first 2-3 plasma discharges. Individual particles moving at velocities up to {approx}300 m/s, breakup of larger particles into pieces, and collisions of particles with walls are observed. After {approx}70 discharges, dust levels are reduced to a few events per discharge. In order to calibrate diagnostics and benchmark modeling, milligram amounts of micron-sized carbon dust have been injected into DIII-D discharges, leading to the core carbon density increase by a factor of 2-3. Following injection, dust trajectories in the divertor are mostly in the toroidal direction, consistent with the ion drag force. Dust from the injection is observed in the outboard midplane by a fast framing camera. The observed trajectories and velocities of the dust particles are in qualitative agreement with modeling by the 3D DustT code.

  13. Spatial distribution, health risk assessment, and isotopic composition of lead contamination of street dusts in different functional areas of Beijing, China.

    PubMed

    Han, Lanfang; Gao, Bo; Wei, Xin; Xu, Dongyu; Gao, Li

    2016-02-01

    Street dusts from heavy density traffic area (HDTA), tourism area (TA), residential area (RA), and educational area (EA) in Beijing were collected to explore the distribution, health risk assessment, and source of lead (Pb). The average concentration of Pb in TA was the highest among the four areas. Compared with other cities, Pb concentrations in Beijing were generally at moderate or low levels. The average value (14.05) of ecological risk index (RI) indicated that Pb was at "low pollution risk" status. According to the calculation on hazard index (HI), the ingestion of dust particles of children and adults was the major route of exposure to street dusts in four studied areas, followed by dermal contact. The lower values of HI than 1 further suggested that non-carcinogenic risks of Pb in the street dusts were in the low range. Comparing (206)Pb/(207)Pb and (208)Pb/(207)Pb ratios of street dusts with other environmental samples, it was found that atmospheric deposition of coal combustion dust might be the main pathway for anthropogenic Pb input to the street dusts in four functional areas.

  14. Mechanical loading leads to osteoarthritis-like changes in the hypofunctional temporomandibular joint in rats.

    PubMed

    Ikeda, Yuhei; Yonemitsu, Ikuo; Takei, Maki; Shibata, Shunichi; Ono, Takashi

    2014-12-01

    Temporomandibular joint (TMJ) hypofunction secondary to feeding a liquid diet in the growing period leads to morphological hypoplasia. However, few studies have evaluated the results of mechanical loading on the hypoplastic TMJ. This study investigated whether TMJ hypofunction in rats causes osteoarthritis (OA)-like changes when exposed to mechanical loading. Male 21-day-old Wistar rats were divided into four groups. The first group (C) served as the control. In the second group (W), mechanical loading was applied to the TMJ by continuous steady mouth opening (3h/day for 5 days) from 63 days of age. A jaw-opening device was used to hold the mandible open in the maximal mouth-opening position with a cobalt-chromium (Co-Cr) wire (φ: 0.9mm). Groups C and W both received a normal hard diet. The third group (L) and fourth group (LW) were fed a liquid diet and group LW were subjected to the same loading as group W. We evaluated the TMJ using micro-CT, toluidine blue staining and immunohistochemistry of matrix metalloproteinase (MMP)-13. In group LW in the superior and posterior regions of the condyle, bone volume fraction, trabecular thickness and trabecular number were significantly decreased and trabecular spacing was significantly increased. The ratio of MMP-13 immunopositive cells was significantly higher than in the other groups. OA-like changes were also observed, including reduced thickness of the cartilage, irregularities in the chondrocytic layer, and cell-free areas. TMJ hypofunction in rats is likely to lead to OA-like changes when exposed to mechanical loading. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Estimating Children's Soil/Dust Ingestion Rates through Retrospective Analyses of Blood Lead Biomonitoring from the Bunker Hill Superfund Site in Idaho.

    PubMed

    von Lindern, Ian; Spalinger, Susan; Stifelman, Marc L; Stanek, Lindsay Wichers; Bartrem, Casey

    2016-09-01

    Soil/dust ingestion rates are important variables in assessing children's health risks in contaminated environments. Current estimates are based largely on soil tracer methodology, which is limited by analytical uncertainty, small sample size, and short study duration. The objective was to estimate site-specific soil/dust ingestion rates through reevaluation of the lead absorption dose-response relationship using new bioavailability data from the Bunker Hill Mining and Metallurgical Complex Superfund Site (BHSS) in Idaho, USA. The U.S. Environmental Protection Agency (EPA) in vitro bioavailability methodology was applied to archived BHSS soil and dust samples. Using age-specific biokinetic slope factors, we related bioavailable lead from these sources to children's blood lead levels (BLLs) monitored during cleanup from 1988 through 2002. Quantitative regression analyses and exposure assessment guidance were used to develop candidate soil/dust source partition scenarios estimating lead intake, allowing estimation of age-specific soil/dust ingestion rates. These ingestion rate and bioavailability estimates were simultaneously applied to the U.S. EPA Integrated Exposure Uptake Biokinetic Model for Lead in Children to determine those combinations best approximating observed BLLs. Absolute soil and house dust bioavailability averaged 33% (SD ± 4%) and 28% (SD ± 6%), respectively. Estimated BHSS age-specific soil/dust ingestion rates are 86-94 mg/day for 6-month- to 2-year-old children and 51-67 mg/day for 2- to 9-year-old children. Soil/dust ingestion rate estimates for 1- to 9-year-old children at the BHSS are lower than those commonly used in human health risk assessment. A substantial component of children's exposure comes from sources beyond the immediate home environment. von Lindern I, Spalinger S, Stifelman ML, Stanek LW, Bartrem C. 2016. Estimating children's soil/dust ingestion rates through retrospective analyses of blood lead biomonitoring from the Bunker

  16. Estimating Children’s Soil/Dust Ingestion Rates through Retrospective Analyses of Blood Lead Biomonitoring from the Bunker Hill Superfund Site in Idaho

    PubMed Central

    von Lindern, Ian; Spalinger, Susan; Stifelman, Marc L.; Stanek, Lindsay Wichers; Bartrem, Casey

    2016-01-01

    Background: Soil/dust ingestion rates are important variables in assessing children’s health risks in contaminated environments. Current estimates are based largely on soil tracer methodology, which is limited by analytical uncertainty, small sample size, and short study duration. Objectives: The objective was to estimate site-specific soil/dust ingestion rates through reevaluation of the lead absorption dose–response relationship using new bioavailability data from the Bunker Hill Mining and Metallurgical Complex Superfund Site (BHSS) in Idaho, USA. Methods: The U.S. Environmental Protection Agency (EPA) in vitro bioavailability methodology was applied to archived BHSS soil and dust samples. Using age-specific biokinetic slope factors, we related bioavailable lead from these sources to children’s blood lead levels (BLLs) monitored during cleanup from 1988 through 2002. Quantitative regression analyses and exposure assessment guidance were used to develop candidate soil/dust source partition scenarios estimating lead intake, allowing estimation of age-specific soil/dust ingestion rates. These ingestion rate and bioavailability estimates were simultaneously applied to the U.S. EPA Integrated Exposure Uptake Biokinetic Model for Lead in Children to determine those combinations best approximating observed BLLs. Results: Absolute soil and house dust bioavailability averaged 33% (SD ± 4%) and 28% (SD ± 6%), respectively. Estimated BHSS age-specific soil/dust ingestion rates are 86–94 mg/day for 6-month- to 2-year-old children and 51–67 mg/day for 2- to 9-year-old children. Conclusions: Soil/dust ingestion rate estimates for 1- to 9-year-old children at the BHSS are lower than those commonly used in human health risk assessment. A substantial component of children’s exposure comes from sources beyond the immediate home environment. Citation: von Lindern I, Spalinger S, Stifelman ML, Stanek LW, Bartrem C. 2016. Estimating children’s soil/dust ingestion

  17. Mathematical Model of Load Pass and Prediction of Fatigue Life on Bolt Threads with Reduced Lead

    NASA Astrophysics Data System (ADS)

    Asayama, Yukiteru

    A mathematical model is proposed in order to elucidate the mechanism that the fatigue strength of external threads increases by reducing the lead on a thread system such as a bolt and nut. The model is constructed from the concept that a local strain proportional to the reducing degree of the lead, although the local strain is at first produced in the bolt thread farthest from the bearing surface of the nut, is induced in each thread root with an increase of applied load. The fatigue life predicted from the mathematical model shows good agreement with the experimental fatigue life of cadmium-plated external threads with the reduced lead on the material having strength as high as 1270MPa. The model can provide useful suggestions for the design of fasteners for aerospace, which are required to satisfy severe requirements of fatigue strengths and dimensions.

  18. Simulating Mars' Dust Cycle with a Mars General Circulation Model: Effects of Water Ice Cloud Formation on Dust Lifting Strength and Seasonality

    NASA Technical Reports Server (NTRS)

    Kahre, Melinda A.; Haberle, Robert; Hollingsworth, Jeffery L.

    2012-01-01

    The dust cycle is critically important for the current climate of Mars. The radiative effects of dust impact the thermal and dynamical state of the atmosphere [1,2,3]. Although dust is present in the Martian atmosphere throughout the year, the level of dustiness varies with season. The atmosphere is generally the dustiest during northern fall and winter and the least dusty during northern spring and summer [4]. Dust particles are lifted into the atmosphere by dust storms that range in size from meters to thousands of kilometers across [5]. Regional storm activity is enhanced before northern winter solstice (Ls200 degrees - 240 degrees), and after northern solstice (Ls305 degrees - 340 degrees ), which produces elevated atmospheric dust loadings during these periods [5,6,7]. These pre- and post- solstice increases in dust loading are thought to be associated with transient eddy activity in the northern hemisphere with cross-equatorial transport of dust leading to enhanced dust lifting in the southern hemisphere [6]. Interactive dust cycle studies with Mars General Circulation Models (MGCMs) have included the lifting, transport, and sedimentation of radiatively active dust. Although the predicted global dust loadings from these simulations capture some aspects of the observed dust cycle, there are marked differences between the simulated and observed dust cycles [8,9,10]. Most notably, the maximum dust loading is robustly predicted by models to occur near northern winter solstice and is due to dust lifting associated with down slope flows on the flanks of the Hellas basin. Thus far, models have had difficulty simulating the observed pre- and post- solstice peaks in dust loading.

  19. Desert dust contribution to PM10 loads in Italy: Methods and recommendations addressing the relevant European Commission Guidelines in support to the Air Quality Directive 2008/50

    NASA Astrophysics Data System (ADS)

    Barnaba, Francesca; Bolignano, Andrea; Di Liberto, Luca; Morelli, Matteo; Lucarelli, Franco; Nava, Silvia; Perrino, Cinzia; Canepari, Silvia; Basart, Sara; Costabile, Francesca; Dionisi, Davide; Ciampichetti, Spartaco; Sozzi, Roberto; Gobbi, Gian Paolo

    2017-07-01

    In 2011 the European Commission (EC) released specific 'Guidelines' describing the methods to quantify and subtract the contribution of natural sources from the PM10 values regulated by the European Air Quality Directive (2008/50/EC). This work investigates the applicability to Italy of the EC-Methodology suggested for desert-dust, describes main limitations encountered and proposes specific modifications embedded within a 'revised-Methodology' to extend/improve its use. The revised-Methodology capabilities are evaluated using original, chemically-resolved mineral-dust mass concentration measurements, showing better performances in predicting timing and absolute values of the desert-dust contribution to the daily-PM10 with respect to the current EC-approach. The revised-Methodology is then translated into an automatic (user-independent) tool tailored to the expected final-users. This tool is applied over Central Italy across a 3-year long period (2012-2014), and over the whole Italian country for a calendar year (2012). The derived results confirm and extend to Italian regions never addressed before some previously observed features of the desert-dust impact over the country, such as a clear latitudinal dependence of the desert-dust impact on the yearly average PM10 (from more than 5 μg/m3 to less than 0.5 μg/m3, going from south to north Italy). The modifications introduced within the revised-Methodology also suggest a non-negligible role of desert-dust resuspension in areas characterized by both high traffic levels and soil sealing (urban areas and along the major Italian routes). In the Rome area, such an effect is found to add a contribution of about 2 μg/m3 (i.e., of 20%) to the mean desert-dust load per dust day (about 10 μg/m3). At the national level, this effect contributes increasing the total number of desert-dust-driven exceedances of the PM10 daily limit value even in the northern regions, where the desert-dust impact on the PM10 yearly average is

  20. Substantial contribution of northern high-latitude sources to mineral dust in the Arctic

    NASA Astrophysics Data System (ADS)

    Groot Zwaaftink, C. D.; Grythe, H.; Skov, H.; Stohl, A.

    2016-11-01

    In the Arctic, impurities in the atmosphere and cryosphere can strongly affect the atmospheric radiation and surface energy balance. While black carbon has hence received much attention, mineral dust has been in the background. Mineral dust is not only transported into the Arctic from remote regions but also, possibly increasingly, generated in the region itself. Here we study mineral dust in the Arctic based on global transport model simulations. For this, we have developed a dust mobilization scheme in combination with the Lagrangian particle dispersion model FLEXPART. A model evaluation, based on measurements of surface concentrations and annual deposition at a number of stations and aircraft vertical profiles, shows the suitability of this model to study global dust transport. Simulations indicate that about 3% of global dust emission originates from high-latitude dust sources in the Arctic. Due to limited convection and enhanced efficiency of removal, dust emitted in these source regions is mostly deposited closer to the source than dust from for instance Asia or Africa. This leads to dominant contributions of local dust sources to total surface dust concentrations ( 85%) and dust deposition ( 90%) in the Arctic region. Dust deposition from local sources peaks in autumn, while dust deposition from remote sources occurs mainly in spring in the Arctic. With increasing altitude, remote sources become more important for dust concentrations as well as deposition. Therefore, total atmospheric dust loads in the Arctic are strongly influenced by Asian ( 38%) and African ( 32%) dust, whereas local dust contributes only 27%. Dust loads are thus largest in spring when remote dust is efficiently transported into the Arctic. Overall, our study shows that contributions of local dust sources are more important in the Arctic than previously thought, particularly with respect to surface concentrations and dust deposition.

  1. Shaped, lead-loaded acrylic filters for patient exposure reduction and image-quality improvement

    SciTech Connect

    Gray, J.E.; Stears, J.G.; Frank, E.D.

    1983-03-01

    Shaped filters that are constructed of lead-loaded acrylic material for use in patient radiography are discussed. Use of the filters will result in improved overall image quality with significant exposure reduction to the patient (approximately a 2X reduction in breast exposure and a 3X reduction in thyroid gland exposure). Detailed drawings of the shaped filters for scoliosis radiography, cervical spine radiography, and for long film changers in special procedures are provided. The use of the scoliosis filters is detailed and includes phantom and patient radiographs and dose reduction information.

  2. Utilization of phosphorus loaded alkaline residue to immobilize lead in a shooting range soil.

    PubMed

    Yan, Yubo; Qi, Fangjie; Seshadri, Balaji; Xu, Yilu; Hou, Jiexi; Ok, Yong Sik; Dong, Xiaoli; Li, Qiao; Sun, Xiuyun; Wang, Lianjun; Bolan, Nanthi

    2016-11-01

    The alkaline residue generated from the production of soda ash using the ammonia-soda method has been successfully used in removing phosphorus (P) from aqueous solution. But the accumulation of P-containing solid after P removal is an undesirable menace to the environment. To achieve the goal of recycling, this study explored the feasibility of reusing the P loaded alkaline residue as an amendment for immobilization of lead (Pb) in a shooting range soil. The main crystalline phase and micromorphology of amendments were determined using X-ray diffraction (XRD) and scanning electron microscopy-electron dispersion spectroscopy (SEM-EDS) methods. The toxicity characteristic leaching procedure (TCLP), sequential extraction procedure, and physiologically based extraction test (PBET) were employed to evaluate the effectiveness of Pb immobilization in soil after 45 d incubation. Treatment with P loaded alkaline residue was significantly effective in reducing the TCLP and PBET extractable Pb concentrations in contrast to the untreated soil. Moreover, a positive change in the distribution of Pb fractions was observed in the treated soil, i.e., more than 60% of soil-Pb was transformed to the residual fraction compared to the original soil. On the other hand, P loaded amendments also resulted in a drastic reduction in phytoavailable Pb to the winter wheat and a mild release of P as a nutrient in treated soil, which also confirmed the improvement of soil quality.

  3. Extremely high aerosol loading over Arabian Sea during June 2008: The specific role of the atmospheric dynamics and Sistan dust storms

    NASA Astrophysics Data System (ADS)

    Kaskaoutis, D. G.; Rashki, A.; Houssos, E. E.; Goto, D.; Nastos, P. T.

    2014-09-01

    This study focuses on analyzing the extreme aerosol loading and the mechanisms, source areas and meteorological conditions that favored the abnormal dust exposure towards Arabian Sea during June 2008. The analysis reveals that the spatial-averaged aerosol optical depth (AOD) over Arabian Sea in June 2008 is 0.5 (78.2%) higher than the 2000-2013 mean June value and is mostly attributed to the enhanced dust activity and several (18) dust storms originated from the Sistan region (Iran-Afghanistan borders). Landsat images show that the marshy lakes in Sistan basin got dried during the second half of June 2008 and the alluvial silt and saline material got easily eroded by the intense Levar winds, which were stronger (>15-20 m s-1) than the climatological mean for the month of June. These conditions led to enhanced dust exposure from Sistan that strongly affected the northern and central parts of the Arabian Sea, as forward air-mass trajectories show. The NCEP/NCAR reanalysis reveals an abnormal intensification and spatial expansion of the Indian low pressure system towards northern Arabian Sea in June 2008. This suggests strengthening of the convection over the arid southwest Asia and exposure of significant amount of dust, which can reach further south over Arabian Sea favored by the enhanced cyclonic circulation. MODIS imagery highlighted several dust storms originated from Sistan and affecting Arabian Sea during June 2008, while the SPRINTARS model simulations of increased AOD and dust concentration over Sistan and downwind areas are in agreement with ground-based and satellite observations.

  4. Physical characterization, magnetic measurements, REE geochemistry and biomonitoring of dust load accumulated during a protracted winter fog period and their implications.

    PubMed

    Chakarvorty, Munmun; Pati, Jayanta Kumar; Patil, Shiva Kumar; Shukla, Swati; Niyogi, Ambalika; Saraf, Arun Kumar

    2014-05-01

    The winter fog in India is a recurrent phenomenon for more than a decade now affecting the entire Himalayan and sub-Himalayan regions covering an area of nearly 500,000 km(2). Every winter (December-January), the air and surface transports in cities of northern India (Amritsar, New Delhi, Agra, Gwalior, Kanpur, Lucknow, and Allahabad) are severely disrupted with visibility reduced to <50 m at times. Since dust particles are known to act as nuclei for the fog formation, this study is aimed to carry out physicochemical characterization of the dust particulates accumulated during a protracted fog period from one of the severely fog affected cities of north India (Allahabad; 25°27'33.40″N-81°52'45.47″E). The dust-loaded tree leaves belonging to Ficus bengalensis and Ficus religiosa from 50 different locations between January 24 and 31, 2010 are sampled and characterized. The mass of dust, color, grain shape, size, phase constituents, and mineral magnetic parameters, such as magnetic susceptibility, SIRM, χ fd%, and S-ratio, show minor variation and the regional influence outweighs local anthropogenic contributions. The dust compositions show fractionated rare earth element pattern with a pronounced negative Eu anomaly similar to upper continental crust and further suggesting their derivation from sources located in parts of north and central India.

  5. Identification of particles containing chromium and lead in road dust and soakaway sediment by electron probe microanalyser.

    PubMed

    Murakami, Michio; Nakajima, Fumiyuki; Furumai, Hiroaki; Tomiyasu, Bunbunoshin; Owari, Masanori

    2007-05-01

    Individual particles containing Cr and/or Pb and other major components were identified in road dust from a heavily used road (hereinafter 'heavy traffic road dust'), road dust from a residential area and soakaway sediment by electron probe microanalyser to locate their sources and carrier particles. Individual particles containing high levels of Cr and/or Pb (>or=0.2%) were identified using wavelength dispersive spectrometry (WDS) map analysis. Chromium, Pb and other major elements were then determined by means of a combination of WDS and energy-dispersive spectrometry in all identified particles, 50 particles containing neither Cr nor Pb from each type of road dust and soakaway sediment, and yellow road line markings. WDS map analysis revealed that many particles containing both Cr and Pb were present among the identified particles in heavy traffic road dust, whereas they were minor components in road dust from the residential area and soakaway sediment. The plots of X-ray intensities of Cr vs. Pb were linear for the identified particles containing both Cr and Pb in heavy traffic road dust, and the line closely fitted the plots for the three yellow road line marking samples. Individual particles were then classified using cluster analysis of element components. The results revealed that the adsorption of source materials or released metals onto soil minerals occurred in road dust and soakaway sediment, that the yellow road line markings were sources of Cr and Pb in heavy traffic road dust, and that materials containing Fe as a major component, such as stainless steel, were additional sources of Cr in both road dust and soakaway sediment.

  6. Comparison of Lead Species in Household Dust Wipes, Soil, and Airborne Particulate Matter in El Paso, Texas, by X-Ray Absorption Spectroscopy

    NASA Astrophysics Data System (ADS)

    Pingitore, N. E.; Clague, J.; Amaya, M. A.

    2006-12-01

    Understanding the interplay of indoor and outdoor sources of lead in an urban setting is one foundation in establishing risk for lead exposure in children in our cities. A household may be the source for lead contamination due to the deterioration of interior lead-based paint, or a sink if lead particles are tracked or blown into the home from such potential ambient sources as yard soil or urban street dust. In addressing this issue, X-Ray Absorption Spectroscopy (XAS) presents the opportunity to directly and quantitatively speciate lead at low concentrations in bulk samples. We performed XAS analyses on dust wipes from window sills or floors from 8 houses that exceeded Federal standards for lead in dust. We entered these data into a Principal Components Analysis (PCA) that also included El Paso environmental samples: lead-based paints, soils, and airborne particulate matter. A simple two-component mixing system accounted for more than 95% of the variance of this data set. Paint and lead oxide appear to be the principal components, with all the samples falling in a compositional range from pure paint to 75% paint, 25% lead oxide. Note that several different lead compounds are possible constituents of a given lead-based paint. The paints spread from one end out along perhaps a fifth of the range of the compositional axis, followed closely, but not overlapped, by the soil samples, which covered the remainder of the compositional range. Two of the dust wipes plotted within the paint range, and the remaining 6 dust wipes plotted randomly through the soil range. Samples of airborne particulate matter plotted in both the paint and soil ranges. These observations suggest that the lead on most of the dust wipes originated outside the house, probably from deteriorated exterior lead-based paint deposited in adjacent yards. This paint mixed with lead oxide present in the soil and entered the houses by the airborne route. The probable source of the oxide in the soil is former

  7. Human health risk assessment of lead, manganese and copper from scrapped car paint dust from automobile workshops in Nigeria.

    PubMed

    Nduka, John Kanayochukwu; Onyenezi Amuka, John Paul; Onwuka, Jude Chinedu; Udowelle, Nnaemeka Arinze; Orisakwe, Orish Ebere

    2016-10-01

    The economic downturn in Nigeria and Structural Adjustment Programme led to the flooding of Nigerian market with imported used automobiles. Most of these vehicles needed refurbishing and reworking. The present study is a human health risk assessment of metal exposure resulting from reworking of imported used vehicles in Nigeria. Scrap paint dusts from 56 Japanese made cars were collected from 8 different mechanic villages (workshops A-H] in Southeastern Nigeria. Scrap paints were homogenized, mixed, divided into fine particles and digested by standard method. The filtrates were assayed of lead, manganese and copper with atomic absorption spectrophotometry (AAS). Workshop B has the highest concentration of Pb (4.26 ± 0.93). Manganese in workshops A and F were (3.31 ± 0.85) and (3.04 ± 0.47) respectively and were higher than the levels from workshops C, B, D, G and H. Copper in workshop D (7.11 ± 0.21) was significantly greater than the other workshops. The highest hazard quotient (HQ) through ingestion, inhalation and dermal exposures in adults were 9.44E-05 (workshop B), 4.20E-01 (workshop B) and 1.08E-05 (workshop D) respectively. The highest values for HQ through ingestion, inhalation and dermal in children were 8.82E-04, 7.61E-01 and 2.86E-05 all in workshop B respectively. For children, the highest carcinogenic risk levels were 7.05E-08, 6.09E-05 and 2.29E-10 for ingestion, inhalation and dermal exposures respectively. In adults, the carcinogenic risk levels were 7.55E-09, 3.39E-05 and 8.67E-10 for ingestion, inhalation and dermal exposures respectively. Chronic exposure to scrap car paint dusts may be of significant public health importance in Nigeria as this may add to the body burden of some heavy metals.

  8. Lesson from Tungsten Leading Edge Heat Load Analysis in KSTAR Divertor

    NASA Astrophysics Data System (ADS)

    Hong, Suk-Ho; Pitts, Richard Anthony; Lee, Hyeong-Ho; Bang, Eunnam; Kang, Chan-Soo; Kim, Kyung-Min; Kim, Hong-Tack; ITER Organization Collaboration; Kstar Team Team

    2016-10-01

    An important design issue for the ITER tungsten (W) divertor and in fact for all such components using metallic plasma-facing elements and which are exposed to high parallel power fluxes, is the question of surface shaping to avoid melting of leading edges. We have fabricated a series of tungsten blocks with a variety of leading edge heights (0.3, 0.6, 1.0, and 2.0 mm), from the ITER worst case to heights even beyond the extreme value tested on JET. They are mounted into adjacent, inertially cooled graphite tile installed in the central divertor region of KSTAR, within the field of view of an infra-red (IR) thermography system with a spatial resolution to 0.4 mm/pixel. Adjustment of the outer divertor strike point position is used to deposit power on the different blocks in different discharges. The measured power flux density on flat regions of the surrounding graphite tiles is used to obtain the parallel power flux, q|| impinging on the various W blocks. Experiments have been performed in Type I ELMing H-mode with Ip = 600 kA, BT = 2 T, PNBI = 3.5 MW, leading to a hot attached divertor with typical pulse lengths of 10 s. Three dimensional ANSYS simulations using q|| and assuming geometric projection of the heat flux are found to be consistent with the observed edge loading. This research was partially supported by Ministry of Science, ICT, and Future Planning under KSTAR project.

  9. Reinstating lead for high-loaded efficient negative electrode for rechargeable sodium-ion battery

    NASA Astrophysics Data System (ADS)

    Darwiche, Ali; Dugas, Romain; Fraisse, Bernard; Monconduit, Laure

    2016-02-01

    Due to its weight and toxicity, Pb is usually not considered as possible anode for Li- and Na-ion (NIBs) batteries. Nevertheless the toxicity is related to specific applications and its recycling is more than 99% which is one of the highest recycling rates on the planet where no other power source is utilized in more applications with such sustainability. For this reason, we have investigated micrometric lead particles as electrode for NIBs in an ether-based electrolyte (1 M NaPF6 in diglyme). The cyclability, coulombic efficiency and rate capability of lead were unexpected. A high loaded lead electrode with 98%wt of Pb and only 1% of carbon additive showed i) a capacity retention of 464 mA h/g after 50 cycles with only 1.5% of capacity loss, which represents a high volumetric capacity of 5289 mA h/cm3 due to the high density of Pb and ii) a very interesting capacity retention even at high current rate (1950 mA/g). In situ XRD study confirmed a sodiation-desodiation process in four steps. Preliminary tests in Pb//Na3V2(PO4)2F3 full cells showed promising results demonstrating that Pb could be a practical candidate for future high energy density Na-ion batteries with an efficient sodiated or non sodiated positive electrode.

  10. Profiles of lead in urban dust and the effect of the distance to multi-industry in an old heavy industry city in China.

    PubMed

    Yu, Yang; Li, Yingxia; Li, Ben; Shen, Zhenyao; Stenstrom, Michael K

    2017-03-01

    Lead (Pb) concentration in urban dust is often higher than background concentrations and can result in a wide range of health risks to local communities. To understand Pb distribution in urban dust and how multi-industrial activity affects Pb concentration, 21 sampling sites within the heavy industry city of Jilin, China, were analyzed for Pb concentration. Pb concentrations of all 21 urban dust samples from the Jilin City Center were higher than the background concentration for soil in Jilin Province. The analyses show that distance to industry is an important parameter determining health risks associated with Pb in urban dust. The Pb concentration showed an exponential decrease, with increasing distance from industry. Both maximum likelihood estimation and Bayesian analysis were used to estimate the exponential relationship between Pb concentration and distance to multi-industry areas. We found that Bayesian analysis was a better method with less uncertainty for estimating Pb dust concentrations based on their distance to multi-industry, and this approach is recommended for further study. Copyright © 2016. Published by Elsevier Inc.

  11. Characterisation of atmospheric deposited particles during a dust storm in urban areas of Eastern Australia.

    PubMed

    Gunawardena, Janaka; Ziyath, Abdul M; Bostrom, Thor E; Bekessy, Lambert K; Ayoko, Godwin A; Egodawatta, Prasanna; Goonetilleke, Ashantha

    2013-09-01

    The characteristics of dust particles deposited during the 2009 dust storm in the Gold Coast and Brisbane regions of Australia are discussed in this paper. The study outcomes provide important knowledge in relation to the potential impacts of dust storm related pollution on ecosystem health in the context that the frequency of dust storms is predicted to increase due to anthropogenic desert surface modifications and climate change impacts. The investigated dust storm contributed a large fraction of fine particles to the environment with an increased amount of total suspended solids, compared to dry deposition under ambient conditions. Although the dust storm passed over forested areas, the organic carbon content in the dust was relatively low. The primary metals present in the dust storm deposition were aluminium, iron and manganese, which are common soil minerals in Australia. The dust storm deposition did not contain significant loads of nickel, cadmium, copper and lead, which are commonly present in the urban environment. Furthermore, the comparison between the ambient and dust storm chromium and zinc loads suggested that these metals were contributed to the dust storm by local anthropogenic sources. The potential ecosystem health impacts of the 2009 dust storm include, increased fine solids deposition on ground surfaces resulting in an enhanced capacity to adsorb toxic pollutants as well as increased aluminium, iron and manganese loads. In contrast, the ecosystem health impacts related to organic carbon and other metals from dust storm atmospheric deposition are not considered to be significant. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Strength Properties of Aged Poled Lead Zirconate Titanate Subjected to Electromechanical Loadings

    SciTech Connect

    Zhang, Kewei; Zeng, Fan W; Wang, Hong; Lin, Hua-Tay

    2012-01-01

    Electric field and aging time are two important factors that affect the mechanical strength and long-term reliability of lead zirconate titanate or PZT actuators. In the present work, a commercial PZT-5A aged four years was examined using ball-on-ring (BoR) mechanical testing under coupled electric fields. The electric field range of -3E{sub c} to +3E{sub c} (E{sub c}, coercive electric field) was studied (i.e., -3E{sub c}, -E{sub c}, 0, +E{sub c}, +2E{sub c}, and +3E{sub c}) with a controlled electric loading path. A Weibull distribution was used to interpret the mechanical strength data. With an electric field preloaded from 0 to -3E{sub c}, it was found that subsequent increases in the electric field resulted in an asymmetrical V-shaped curve of mechanical strength against the electric field. The bottom of the V curve was located near the zero electric field level. Microscopy analysis showed that pores were the strength limiter for the tested PZT under electromechanical loadings.

  13. Hydrometallurgical recovery of zinc and lead from electric arc furnace dust using mononitrilotriacetate anion and hexahydrated ferric chloride.

    PubMed

    Leclerc, Nathalie; Meux, Eric; Lecuire, Jean Marie

    2002-04-26

    The purpose of this work was to study the feasibility at laboratory-scale of a new hydrometallurgical process for treating electric arc furnace dusts (EAFD). The proposed process is intended to extract zinc and lead from EAFD without destroying the iron oxides matrix. So, this material can be recycled by the steel industry. Independently of the origin of the samples, major mineralogical forms present in these wastes are Fe3O4, ZnO, ZnFe2O4 and PbOHCl. The proposed process consists of a hydrometallurgical treatment of wastes based on selective leaching of zinc and lead. Initially, a leaching is carried out utilizing a chelating agent, nitrilotriacetate anion (NTA3-), as the protonated form HNTA2-. Treatment of five EAFD samples for an hour at room temperature with a molar solution of reagent results in total leaching of the ZnO. In all cases the solubilized iron does not exceed 3 wt.%. The recovery of zinc and lead is performed by precipitation of metallic sulfides with a solution of Na2S4 sodium tetrasulfide 2M. These metallic sulfides can be used as metallurgical raw materials and the chelating reagent can be reused in the process after pH adjustment. The results of the normalized leaching test AFNOR X31-210 conducted on the leaching residues, shows that all the samples meet acceptance thresholds for hazardous wastes landfill. However, the residues contain a considerable amount of zinc as ZnFe2O4. The extraction of the zinc element requires the destruction of the ferrite structure. In this process, ZnFe2O4 is treated by FeCl3.6H2O. The reaction consists in a particle O2-/Cl- exchange allowing the recovery of zinc as ZnCl2 and iron as hematite Fe2O3. The separation of these products is accomplished by simple aqueous leaching. All of the zinc is extracted in a 8h treatment at 150 degrees C with a molar ratio FeCl3.6H2O/ZnFe2O4 equal to 10. Ultimate solid residues, which have been concentrated in iron, can be oriented towards the steel industry.

  14. Human lead (Pb) exposure via dust from different land use settings of Pakistan: A case study from two urban mountainous cities.

    PubMed

    Eqani, Syed Ali Musstjab Akber Shah; Khalid, Ramsha; Bostan, Nazish; Saqib, Zafeer; Mohmand, Jawad; Rehan, Mohammad; Ali, Nadeem; Katsoyiannis, Ioannis A; Shen, Heqing

    2016-07-01

    The current study aims to determine the dust-borne lead (Pb) levels into outdoor dust, which were collected from the areas nearby the cities/districts of Islamabad and Swat in Pakistan. In general dust samples from all land use settings (industrial, urban and rural) showed significantly higher (p<0.05) Pb-levels (median, ppm) from Islamabad (110, 52, 24) than those of Swat district (75, 37, 21), respectively. Index of Geo-accumulation (Igeo values) indicated that industrial and urban areas of both sites were highly polluted due to severe anthropogenic influence, whereas the rural areas were in most parts unpolluted and where moderately polluted, this was mainly due to geological factors and short and/or long distance atmospheric deposition from surrounding polluted areas. According to the calculated chemical daily intake (mg/kg-day) values, dust ingestion is one of the major routes of human exposure for lead. Hazard Index (HI) values, calculated for both adult and children populations, were above unity in industrial and urban areas, indicating serious health risks especially to the children populations.

  15. Comparison of home lead dust reduction techniques on hard surfaces: the New Jersey assessment of cleaning techniques trial.

    PubMed

    Rich, David Q; Rhoads, George G; Yiin, Lih-Ming; Zhang, Junfeng; Bai, Zhipeng; Adgate, John L; Ashley, Peter J; Lioy, Paul J

    2002-09-01

    High efficiency particulate air filter (HEPA) vacuums, which collect particles > 0.3 micro m, and trisodium phosphate (TSP), a detergent claimed to selectively remove lead, have been included in the HUD Guidelines for the Evaluation and Control of Lead Based Paint Hazards in Housing without systematic validation of their effectiveness. At the time the study was initiated, both HEPA vacuums and TSP were relatively expensive, they were not readily found in urban retail centers, and there were environmental concerns about the use and disposal of high-phosphate detergents. A randomized, controlled trial was conducted in urban high-risk homes in northern New Jersey to determine whether a more readily available and less expensive low-phosphate, non-TSP detergent and non-HEPA vacuum could perform as well as TSP and a HEPA vacuum in a cleaning protocol. Homes were randomized to one of three cleaning methods: TSP/HEPA vacuum, TSP/non-HEPA vacuum, or non-TSP/non-HEPA vacuum. Change in log-transformed lead loading was used in mixed models to compare the efficacy of the three cleaning techniques separately for uncarpeted floors, window sills, and window troughs. After we adjusted for baseline lead loading, the non-HEPA vacuum produced larger reductions on hard floors [19%; 95% confidence interval (CI), 3-38%], but the HEPA vacuum produced larger reductions on window sills (22%; 95% CI, 11-32%) and larger reductions on window troughs (16%; 95% CI, -4 to 33%). The non-TSP produced larger reductions on window troughs (21%; 95% CI, -2 to 50%), but TSP produced larger reductions on hard floors (5%; 95% CI, -12 to 19%) and window sills (8%; 95% CI, -5 to 20%). TSP/HEPA produced larger reductions on window sills (28%; 95% CI, 18-37%) and larger reductions on window troughs (2%; 95% CI, -24 to 23%), whereas the non-TSP/non-HEPA method produced larger reductions on hard floors (13%; 95% CI, -5 to 34%). Because neither vacuum nor detergent produced consistent results across surface

  16. Lead

    MedlinePlus

    ... EPA United States Environmental Protection Agency Search Search Lead Contact Us Share Lead Poisoning is Preventable If your home was built ... to protect people from harmful lead exposures. Less Lead in Drinking Water = Better Health Learn about the ...

  17. Lead Poisoning

    MedlinePlus

    ... high levels of lead in household dust. DRINKING WATER: Lead may get into drinking water when materials used in plumbing materials, such as ... and dishware. Lead may also be in contaminated water. Lead poisoning is harmful to human health and ...

  18. Detecting and assessing Saharan dust contribution to PM10 loads: A pilot study within the EU-Life+10 project DIAPASON

    NASA Astrophysics Data System (ADS)

    Gobbi, Gian Paolo; Barnaba, Francesca; Bolignano, Andrea; Costabile, Francesca; Di Liberto, Luca; Dionisi, Davide; Drewnick, Frank; Lucarelli, Franco; Manigrasso, Maurizio; Nava, Silvia; Sauvage, Laurent; Sozzi, Roberto; Struckmeier, Caroline; Wille, Holger

    2015-04-01

    The EC LIFE+2010 DIAPASON Project (Desert dust Impact on Air quality through model-Predictions and Advanced Sensors ObservatioNs, www.diapason-life.eu) intends to contribute new methodologies to assess the role of aerosol advections of Saharan dust to the local PM loads recorded in Europe. To this goal, automated Polarization Lidar-Ceilometers (PLCs) were prototyped within DIAPASON to certify the presence of Saharan dust plumes and support evaluating their mass loadings in the lowermost atmosphere. The whole process also involves operational dust forecasts, as well as satellite and in-situ observations. Demonstration of the Project is implemented in the pilot region of Rome (Central Italy) where three networked DIAPASON PLCs started, in October 2013 a year-round, 24h/day monitoring of the altitude-resolved aerosol backscatter and depolarization profiles. Two intensive observational periods (IOPs) involving chemical analysis and detailed physical characterization of aerosol samples have also been carried out in this year-long campaign, namely in Fall 2013 and Spring 2014. These allowed for an extensive interpretation of the PLC observations, highlighting important synergies between the PLC and the in situ data. The presentation will address capabilities of the employed PLCs, observations agreement with model forecasts of dust advections, retrievals of aerosol properties and methodologies developed to detect Saharan advections and to evaluate the relevant mass contribution to PM10. This latter task is intended to provide suggestions on possible improvements to the current EC Guidelines (2011) on this matter. In fact, specific Guidelines are delivered by the European Commission to provide the Member States a common method to asses the Saharan dust contribution to the currently legislated PM-related Air Quality metrics. The DIAPASON experience shows that improvements can be proposed to make the current EC Methodology more robust and flexible. The methodology DIAPASON

  19. The effects of water restriction and water loading on urinary excretion of lead, delta-aminolevulinic acid and coproporphyrin.

    PubMed Central

    Araki, S

    1978-01-01

    Alterations in daily urinary excretion of lead, delta-aminolevulinic acid (ALA), coproporphyrin, creatinine and total solutes following water restriction and water loading were examined in nine lead workers. Excretion of lead, ALA and total solutes was significantly decreased when urinary volume was reduced, showing that these values are dependent on urinary volume: conversely, excretion of coproporphyrin and creatinine was independent of urinary volume. Excretion of lead and total solutes was also dependent on creatinine excretion. The renal excretory mechanism of lead, ALA and coproporphyrin is discussed in the light of these findings. PMID:737138

  20. In vitro bioaccessibility of lead in surface dust and implications for human exposure: A comparative study between industrial area and urban district.

    PubMed

    Bi, Xiangyang; Li, Zhonggen; Sun, Guangyi; Liu, Jinling; Han, Zhixuan

    2015-10-30

    In this study, ground surface dust samples from two contrasting areas, a former zinc smelting area in Guizhou Province and a common urban district in Wuhan city, Hubei Province, China, were assessed for in vitro Pb bioaccessibility using a physiologically based extraction test (PBET). Extremely elevated concentrations of Pb (220-6348 mg/kg) and other trace metals were observed in the zinc smelting area. While moderate high metal concentrations (79-1544 mg/kg of Pb) in the urban dusts were attributed to various urban activities, coal combustion and traffic emissions. Lead bioaccessibility in the stomach-phase varied from 17.6 to 76.1% and no significant difference was found between industrial and urban dust samples. Compared with the stomach-phase, Pb bioaccessibility in the more alkaline intestinal-phase was considerably lower (1.2-21.8%). A significantly negative correlation was found between dust Ca concentrations and Pb bioaccessibility in the intestinal-phase, suggesting that Ca plays an important role in reducing the bioaccessible Pb in the intestinal-phase. The estimated Pb exposure based on gastric bioaccessible Pb was 13.9 and 1.8 μg/kg day for children living in the industrial and urban areas, respectively, accounting for 85% and 41% of their corresponding total Pb exposure. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Acute acetaminophen intoxication leads to hepatic iron loading by decreased hepcidin synthesis.

    PubMed

    van Swelm, Rachel P L; Laarakkers, Coby M M; Blous, Linda; Peters, Janny G P; Blaney Davidson, Esmeralda N; van der Kraan, Peter M; Swinkels, Dorine W; Masereeuw, Rosalinde; Russel, Frans G M

    2012-09-01

    Acetaminophen (APAP), a major cause of acute liver injury in the Western world, is mediated by metabolism and oxidative stress. Recent studies have suggested a role for iron in potentiating APAP-induced liver injury although its regulatory mechanism is not completely understood. The current study was designed to unravel the iron-regulating pathways in mice after APAP-induced hepatotoxicity. Mice with severe injury showed a significant increase in liver iron concentration and oxidative stress. Concurrently, the plasma concentration of hepcidin, the key regulator in iron metabolism, and hepatic hepcidin antimicrobial peptide (Hamp) mRNA expression levels were significantly reduced. We showed that hepcidin transcription was inhibited via several hepcidin-regulating factors, including the bone morphogenetic protein/small mother against decapentaplegic (BMP/SMAD) pathway, CCAAT/enhancer-binding protein α (C/EBPα), and possibly also via erythropoietin (EPO). Downregulation of the BMP/SMAD signaling pathway was most likely caused by hypoxia-inducible factor 1α (HIF-1α), which was increased in mice with severe APAP-induced liver injury. HIF-1α stimulates cleaving of hemojuvelin, the cofactor of the BMP receptor, thereby blocking BMP-induced signaling. In addition, gene expression levels of C/ebpα were significantly reduced, and Epo mRNA expression levels were significantly increased after APAP intoxication. These factors are regulated through HIF-1α during oxidative stress and suggest that HIF-1α is a key modulator in reduced hepcidin transcription after APAP-induced hepatotoxicity. In conclusion, acute APAP-induced liver injury leads to activation of HIF-1α, which results in a downregulation in hepcidin expression through a BMP/SMAD signaling pathway and through C/EBPα inhibition. Eventually, this leads to hepatic iron loading associated with APAP cytotoxicity.

  2. Thiol Peroxidase Deficiency Leads to Increased Mutational Load and Decreased Fitness in Saccharomyces cerevisiae

    PubMed Central

    Kaya, Alaattin; Lobanov, Alexei V.; Gerashchenko, Maxim V.; Koren, Amnon; Fomenko, Dmitri E.; Koc, Ahmet; Gladyshev, Vadim N.

    2014-01-01

    Thiol peroxidases are critical enzymes in the redox control of cellular processes that function by reducing low levels of hydroperoxides and regulating redox signaling. These proteins were also shown to regulate genome stability, but how their dysfunction affects the actual mutations in the genome is not known. Saccharomyces cerevisiae has eight thiol peroxidases of glutathione peroxidase and peroxiredoxin families, and the mutant lacking all these genes (∆8) is viable. In this study, we employed two independent ∆8 isolates to analyze the genome-wide mutation spectrum that results from deficiency in these enzymes. Deletion of these genes was accompanied by a dramatic increase in point mutations, many of which clustered in close proximity and scattered throughout the genome, suggesting strong mutational bias. We further subjected multiple lines of wild-type and ∆8 cells to long-term mutation accumulation, followed by genome sequencing and phenotypic characterization. ∆8 lines showed a significant increase in nonrecurrent point mutations and indels. The original ∆8 cells exhibited reduced growth rate and decreased life span, which were further reduced in all ∆8 mutation accumulation lines. Although the mutation spectrum of the two independent isolates was different, similar patterns of gene expression were observed, suggesting the direct contribution of thiol peroxidases to the observed phenotypes. Expression of a single thiol peroxidase could partially restore the growth phenotype of ∆8 cells. This study shows how deficiency in nonessential, yet critical and conserved oxidoreductase function, leads to increased mutational load and decreased fitness. PMID:25173844

  3. Accumulation, elimination, sequestration, and genetic variation of lead (Pb(2+)) loads within and between generations of Drosophila melanogaster.

    PubMed

    Peterson, Elizabeth K; Wilson, Diane T; Possidente, Bernard; McDaniel, Phillip; Morley, Eric J; Possidente, Debra; Hollocher, Kurt T; Ruden, Douglas M; Hirsch, Helmut V B

    2017-08-01

    We examined accumulation, sequestration, elimination, and genetic variation for lead (Pb) loads within and between generations of Drosophila melanogaster. Flies were reared in control or leaded medium at various doses and tested for their Pb loads at different stages of development (larvae, eclosion, newly-eclosed adults, and mature adults). Pb loads were tested using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). We found that D. melanogaster readily accumulated Pb throughout their lifespan and the levels of accumulation increased with Pb exposure in the medium. Wandering third-instar larvae accumulated more Pb than mature adults; this phenomenon may be due to elimination of Pb in the pupal cases during eclosion and/or depuration in adults post-eclosion. The accumulated Pb in mature adults was not transferred to F1 mature adult offspring. Using a set of recombinant inbred strains, we identified a quantitative trait locus for adult Pb loads and found that genetic variation accounted for 34% of the variance in Pb load. We concluded that D. melanogaster is a useful model organism for evaluating changes in Pb loads during development, as well as between generations. Furthermore, we found that genetic factors can influence Pb loads; this provides an essential foundation for evaluating phenotypic variation induced by the toxic effects of Pb. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Airborne soil dust and its importance in buffering of atmospheric acidity and critical load assessment, over the semi arid tract of northern India.

    NASA Astrophysics Data System (ADS)

    Sharma, Disha; Kulshrestha, Umesh

    Airborne soil dust and its importance in buffering of atmospheric acidity and critical load assessment, over the semi arid tract of northern India. The Critical Load approach alongwith integrated assessment models has been used in the European nations for policy formations to reduce acidic emissions. This unique approach was applied to assess the of vulnerability of natural systems to the present day atmospheric pollution scenario. The calculated values of critical loads of sulphur ( 225 - 275 eq/ha/yr) and nitrogen (298 - 303 eq/ha/yr), for the soil system in Delhi, were calculated with respect to Anjan grass, Hibiscus and Black siris. The present loads of sulphur (PL(S) = 26.40 eq/ha/yr) and nitrogen (PL(N) = 36.51 eq/ha/yr) were found to be much lower than their critical loads without posing any danger of atmospheric acidic deposition on the soil systems. The study indicated that the system is still protective due to high pH of soil. The nature of buffering capability of calcium derived from soil dust can be considered as a natural tool to combat acidification in the Indian region. The results showed that the pollution status in Delhi is still within the safe limits. However, at the pace at which the city is growing, it is likely that in coming decades, it may exceed these critical values. In order to set deposition limits and avoid adverse effects of acidic deposition this approach can be applied in India too. Such approach is very useful, not only in abating pollution but also in devising means of cost optimal emission abatement strategies.

  5. Sulfidation of lead-loaded zeolite microparticles and flotation by amylxanthate.

    PubMed

    Walcarius, Alain; Marouf, Bouchaïb; Lamdaouar, Ali M; Chlihi, Khadija; Bessiere, Jacques

    2006-02-14

    The possibility of recovering lead-loaded zeolite Y microparticles (PbY) by flotation after sulfidation was investigated using amyl xanthate (AMX) as the collector. The sulfidation process (by aqueous Na2S) was first studied as a function of the medium composition (Na2S concentration, pH), and the solid phases were characterized by various physicochemical techniques (X-ray photoelectron spectroscopy, high-frequency impedance measurements, and electrochemistry). Progressively increasing the sulfidation level resulted in the concomitant transformation of Pb(II) species ion-exchanged in the zeolite into PbS clusters that were mostly located at the external boundaries of the zeolite particles while remaining attached to the aluminosilicate (PbS-Y). Similar to what occurred for galena particles, the zeolite-supported PbS clusters were likely to adsorb the AMX collector, the remaining (nonsulfided) ion-exchanged Pb(II) species being transformed into a Pb(AMX)2 precipitate when using AMX in large excess. Owing to such AMX adsorption on PbS-Y, the zeolite particles were found to flocculate and to float in the presence of air bubbles. If rather high AMX concentrations (>5 x 10(-3) M) were necessary to ensure the flotation of nonsulfided PbY particles (Walcarius, A.; Lamdaouar, A. M.; El Kacemi, K.; Marouf, B.; Bessiere, J. Langmuir 2001, 17, 2258), significantly lower concentrations (down to 1 x 10(-4) M) gave rise to high flotation yields (ca. 95%) upon PbY sulfidation. It is noteworthy that the sulfidation level should be maintained at a value high enough (>10%) to produce the minimal PbS amount ensuring flotation but not too high (<75%) to avoid conditions that are too reducing and are not compatible with the flotation process. Finally, depression tests seemed to indicate that PbS-Y flotation occurs according to a mechanism similar to that described for the galena mineral.

  6. Dust and the Mars Polar Vortices

    NASA Astrophysics Data System (ADS)

    Guzewich, S.; Waugh, D.; Toigo, A. D.

    2015-12-01

    Dust is a highly variable forcing mechanism altering martian atmospheric dynamics. The greatest variability in atmospheric dust opacity occurs during Mars' northern hemisphere fall and winter, the canonical "dust storm season". The northern polar vortex develops during this season and can be stretched, weakened, or strengthened by variations in atmospheric dust. Additionally, Mars' north polar vortex manifests as an annulus of high potential vorticity around the geographic pole, which is distinctly different than Earth's stratospheric polar vortices where potential vorticity peaks at the pole. We examine the role of dust in shaping and altering the martian polar vortices in a series of idealized MarsWRF general circulation model simulations. Increasing dust loading disrupts the northern polar vortex near the winter solstice leading to a "mid-winter warming", and this is also seen in observations from the Mars Climate Sounder and Thermal Emission Spectrometer during large dust events. These appear loosely analogous with terrestrial "sudden stratospheric warming" events, where the strong westerly jet around the pole weakens and air inside the vortex quickly warms. The southern hemisphere winter polar vortex is distinctly different from that of the northern hemisphere, and we show that the fundamental "handedness" of the current martian climactic regime makes the southern hemisphere vortex less sensitive to dust forcing.

  7. Identification of trace metal pollution in urban dust from kindergartens using magnetic, geochemical and lead isotopic analyses

    NASA Astrophysics Data System (ADS)

    Zhu, Zongmin; Sun, Guangyi; Bi, Xiangyang; Li, Zhonggen; Yu, Genhua

    2013-10-01

    In the present study, magnetic measurements were combined with geochemical analysis and stable Pb isotopic ratios to reveal the distribution and origination of trace metal pollutants in kindergarten dusts from a typical urban environment of Wuhan, central China. The geoaccumulation index (Igeo) of magnetic properties was more prominent than those of individual metals. The magnetic susceptibility (MS) and trace metals (Zn, Pb, and Cu) in this study together with published results from other Chinese cities formed a liner relationship, suggesting that metal contaminants in Chinese urban areas had similar MS to metal ratios, which could be used as an indicator for identification of pollution sources between Chinese cities and the other Asian cities. Stable Pb isotopic ratios (1.1125-1.1734 for 206Pb/207Pb and 2.4457-2.4679 for 208Pb/207Pb) in the urban dusts from Wuhan were characterized by higher 208Pb component in comparison with those from other Chinese cities. This result combined with principal component analysis (PCA) indicated that metal pollutants in the dusts were derived from industrial activities and coal combustion, whereas the traffic emissions were no longer a predominant pollution source in urban environment. Our study demonstrated that environmental magnetic methods could not only reveal the overall situation of trace metal contamination, but also prove evidence in the identification of pollution sources.

  8. The effects of dust on Colorado mountain snow cover albedo and compositional links to dust-source areas

    NASA Astrophysics Data System (ADS)

    Goldstein, H. L.; Reynolds, R. L.; Landry, C.; Derry, J. E.; Kokaly, R. F.; Breit, G. N.

    2016-12-01

    Dust deposited on mountain snow cover (DOS) changes snow albedo, enhances absorption of solar radiation, and effectively increases rates of snow melt, leading to earlier-than-normal runoff and overall smaller late-season water supplies for tens of millions of people and industries in the American West. Visible-spectrum reflectance of DOS samples is on the order of 0.2 (80% absorption), in stark contrast to the high reflectivity of pure snow which approaches 1.0. Samples of DOS were collected from 12 high-elevation Colorado mountain sites near the end of spring from 2013 through 2016 prior to complete snow melt, when most dust layers had merged into one layer. These samples were analyzed to measure dust properties that affect snow albedo and to link DOS to dust-source areas. Dust mass loadings to snow during water year 2014 varied from 5 to 30 g/m2. Median particle sizes centered around 20 micrometers with more than 80% of the dust <63 micrometers. Dark minerals, carbonaceous matter, and iron oxides, including nano-sized hematite and goethite, together diminished reflectance according to their variable concentrations. Documenting variations in dust-particle masses, sizes, and compositions helps determine their influences on snow-melt and may be useful for modeling snow-melt effects from future dust. Furthermore, variations in dust components and particle sizes lead to new ways to recognize sources of dust by comparison with properties of fine-grained sediments in dust-source areas. Much of the DOS in the San Juan Mountains, Colorado can be linked to southern Colorado Plateau source areas by compositional similarities and satellite imagery. Understanding dust properties that affect snow albedo and recognizing the sources of dust deposited on snow cover may guide mitigation of dust emission that affects water resources of the Colorado River basin.

  9. Schumann resonances at Mars: Effects of the day-night asymmetry and the dust-loaded ionosphere

    NASA Astrophysics Data System (ADS)

    Toledo-Redondo, S.; Salinas, A.; Portí, J.; Witasse, O.; Cardnell, S.; Fornieles, J.; Molina-Cuberos, G. J.; Déprez, G.; Montmessin, F.

    2017-01-01

    Schumann resonances are standing waves that oscillate in the electromagnetic cavity formed between the conducting lower ionosphere and the surface of the planet. They have been measured in situ only on Earth and Titan, although they are believed to exist on other planets like Mars. We report numerical simulations of the Martian electromagnetic cavity, accounting for the day-night asymmetry and different dust scenarios. It has been found that the resonances are more energetic on the nightside, the first resonance is expected to be 9-14 Hz depending on the dust activity and to have low quality factors (Q≃2). This work serves as an input for the upcoming Exomars surface platform (launch 2020), who will attempt to measure them for the first time.

  10. Real time monitoring of spot-welded joints under service load using lead zirconate titanate (PZT) transducers

    NASA Astrophysics Data System (ADS)

    Yao, Ping; Zheng, Botong; Dawood, Mina; Huo, Linsheng; Song, Gangbing

    2017-03-01

    This paper proposes a nondestructive method to evaluate the health status of resistance spot-welded (RSW) joint under service load using lead zirconate titanate (PZT) active sensing system, in which the PZT transducers were used as both actuator and sensor. The physical principle of the approach was validated through a numerical analysis showing that an opening between the faying faces at the welded joint occurred under tension load. The opening decreased the contact area hence reduced the amplitude of the stress wave received by the PZT sensor. Therefore, by comparing the energy index of the signals before and after the loading, the health condition of the joint can be evaluated. Five ST14 steel single lap joint specimens were tested under tension load while being monitored by the PZT sensing system and digital image correlation (DIC) system in real time. The data obtained from the DIC system validated the numerical results. By comparing the energy index of the signal obtained from the PZT sensing system before and after unloading, it was concluded that the RSW joint was intact after being loaded to the service load. The proposed method is promising in evaluating the health condition of RSW joint nondestructively.

  11. Lead

    MedlinePlus

    ... are approximately half a million U.S. children ages 1-5 with blood lead levels above 5 micrograms per deciliter (µg/dL), the reference level at which CDC recommends public health actions be initiated. No safe blood lead level in children has been ...

  12. Tungsten dust impact on ITER-like plasma edge

    SciTech Connect

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

    2015-01-15

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

  13. Tungsten dust impact on ITER-like plasma edge

    DOE PAGES

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

    2015-01-12

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

  14. Tungsten dust impact on ITER-like plasma edge

    SciTech Connect

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

    2015-01-12

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

  15. Sensitivity of the dust cycle in a Chemistry-GCM

    NASA Astrophysics Data System (ADS)

    Gläser, G.; Kerkweg, A.; Wernli, H.

    2010-09-01

    Mineral dust is an important part of the atmospheric aerosol. The export of Saharan dust across the Atlantic Ocean to the South American continent is known to be an important source of nutrition to the rain forest and the sea. Dust mobilisation in deserts and long-range transport occurs in episodic events and is strongly influenced by synoptic-scale flow patterns. The scientific understanding of these processes, the resulting global dust distribution and the climate impact is still low. In this study, the atmospheric chemistry general circulation model ECHAM5/MESSy (EMAC) is used to simulate the mineral dust cycle. We performed free-running 5-year time slice simulations and nudged experiments for selected dust emission episodes. Two different dust emission schemes and four different horizontal resolutions have been used for investigating their influence on the entire dust cycle. The horizontal resolutions T42 (~312 km), T63 (~208 km), T85 (~155 km) and T106 (~125 km) are explored. Independent of the horizontal resolution the "Balkanski" dust emission scheme simulates global maxima of the dust emissions and the dust column mass in the north-western part of India. Various observations indicate that in reality the maximum lies over the Sahara Desert. The "Tegen" dust emission scheme shows a much more realistic distribution. For all horizontal resolutions both schemes simulate dust emissions, total dust load and a dust life time within the range of the 15 GCMs participating in the AEROCOM-project (Aerosol Comparisons between Observations and Models). However, in T42 and T63 the northward transport of dust is too strong leading to unrealistic high column masses in high northern latitudes. The transport and subsequently the global dust distribution in T85 and T106 is much more sensible. The dust emission (total load) is 28 % (16 %) higher in T106 as in T85 which is traced back to higher wind velocities in T106. In addition to these climatological investigations, the

  16. Low Substrate Loading Limits Methanogenesis and Leads to High Coulombic Efficiency in Bioelectrochemical Systems.

    PubMed

    Sleutels, Tom H J A; Molenaar, Sam D; Heijne, Annemiek Ter; Buisman, Cees J N

    2016-01-05

    A crucial aspect for the application of bioelectrochemical systems (BESs) as a wastewater treatment technology is the efficient oxidation of complex substrates by the bioanode, which is reflected in high Coulombic efficiency (CE). To achieve high CE, it is essential to give a competitive advantage to electrogens over methanogens. Factors that affect CE in bioanodes are, amongst others, the type of wastewater, anode potential, substrate concentration and pH. In this paper, we focus on acetate as a substrate and analyze the competition between methanogens and electrogens from a thermodynamic and kinetic point of view. We reviewed experimental data from earlier studies and propose that low substrate loading in combination with a sufficiently high anode overpotential plays a key-role in achieving high CE. Low substrate loading is a proven strategy against methanogenic activity in large-scale reactors for sulfate reduction. The combination of low substrate loading with sufficiently high overpotential is essential because it results in favorable growth kinetics of electrogens compared to methanogens. To achieve high current density in combination with low substrate concentrations, it is essential to have a high specific anode surface area. New reactor designs with these features are essential for BESs to be successful in wastewater treatment in the future.

  17. Low Substrate Loading Limits Methanogenesis and Leads to High Coulombic Efficiency in Bioelectrochemical Systems

    PubMed Central

    Sleutels, Tom H. J. A.; Molenaar, Sam D.; Heijne, Annemiek Ter; Buisman, Cees J. N.

    2016-01-01

    A crucial aspect for the application of bioelectrochemical systems (BESs) as a wastewater treatment technology is the efficient oxidation of complex substrates by the bioanode, which is reflected in high Coulombic efficiency (CE). To achieve high CE, it is essential to give a competitive advantage to electrogens over methanogens. Factors that affect CE in bioanodes are, amongst others, the type of wastewater, anode potential, substrate concentration and pH. In this paper, we focus on acetate as a substrate and analyze the competition between methanogens and electrogens from a thermodynamic and kinetic point of view. We reviewed experimental data from earlier studies and propose that low substrate loading in combination with a sufficiently high anode overpotential plays a key-role in achieving high CE. Low substrate loading is a proven strategy against methanogenic activity in large-scale reactors for sulfate reduction. The combination of low substrate loading with sufficiently high overpotential is essential because it results in favorable growth kinetics of electrogens compared to methanogens. To achieve high current density in combination with low substrate concentrations, it is essential to have a high specific anode surface area. New reactor designs with these features are essential for BESs to be successful in wastewater treatment in the future. PMID:27681899

  18. Lead Poisoning

    MedlinePlus

    ... through deteriorating paint, household dust, bare soil, air, drinking water, food, ceramics, home remedies, hair dyes and other ... an elevated blood lead level can easily result. Drinking water can also sometimes contribute to elevated blood lead ...

  19. Postoperative Increased Loading Leads to an Alteration in the Radiological Mechanical Axis After Total Knee Arthroplasty.

    PubMed

    Zahn, Robert Karl; Fussi, Jasmin; von Roth, Philipp; Perka, Carsten F; Hommel, Hagen

    2016-08-01

    Standing long-leg radiographs allow assessment of the mechanical axis in the frontal plane before and after total knee arthroplasty (TKA). An alteration in loading, and hence in the forces acting on the knee joint, occurs postoperatively. We therefore postulated that the mechanical axis measured in the long-leg standing radiograph would change within the first year after TKA. Standing long-leg radiographs of 156 patients were performed 7 days, 3 months, and 12 months after TKA with determination of mechanical axis of the lower limb. Seven days after surgery, the mechanical axis amounted 0.8° ± 1.7° valgus. Three months after the operation, at 1.3° ± 1.3° varus, it was significantly different (P < .001) from the primary measurement. No further alteration in the mechanical axis occurred during the first year after TKA. This difference was even more pronounced (P < .001) in patients with a postoperative lack of complete extension. Seven days after surgery, they had a valgus axis deviation of 1.6° ± 1.6°; after 3 months, the measurement amounted 1.2° ± 1.3° varus. Measured by a standing long-leg radiograph, the frontal mechanical axis after TKA changes over time. The predictive power of a standing long-leg radiograph in the first week after surgery is limited because limb loading is altered because of pain and is therefore nonphysiological. The actual mechanical axis resulting after TKA can only be assessed in a standing long-leg radiograph at physiological loading. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Peeling Lead Paint Turns into Poisonous Dust. Guess Where It Ends Up? A Media Campaign to Prevent Childhood Lead Poisoning in New York City

    ERIC Educational Resources Information Center

    Greene, Danielle; Tehranifar, Parisa; DeMartini, Diana P.; Faciano, Andrew; Nagin, Deborah

    2015-01-01

    Successful public health media campaigns promote messages, increase awareness, engage the public, and encourage behavior change. Between 2004 and 2006, the Lead Poisoning Prevention Program of the New York City Department of Health and Mental Hygiene conducted a media campaign grounded in social learning theory and the social marketing model to…

  1. Peeling Lead Paint Turns into Poisonous Dust. Guess Where It Ends Up? A Media Campaign to Prevent Childhood Lead Poisoning in New York City

    ERIC Educational Resources Information Center

    Greene, Danielle; Tehranifar, Parisa; DeMartini, Diana P.; Faciano, Andrew; Nagin, Deborah

    2015-01-01

    Successful public health media campaigns promote messages, increase awareness, engage the public, and encourage behavior change. Between 2004 and 2006, the Lead Poisoning Prevention Program of the New York City Department of Health and Mental Hygiene conducted a media campaign grounded in social learning theory and the social marketing model to…

  2. Peeling lead paint turns into poisonous dust. Guess where it ends up? A media campaign to prevent childhood lead poisoning in New York City.

    PubMed

    Greene, Danielle; Tehranifar, Parisa; DeMartini, Diana P; Faciano, Andrew; Nagin, Deborah

    2015-06-01

    Successful public health media campaigns promote messages, increase awareness, engage the public, and encourage behavior change. Between 2004 and 2006, the Lead Poisoning Prevention Program of the New York City Department of Health and Mental Hygiene conducted a media campaign grounded in social learning theory and the social marketing model to increase parents' awareness of childhood lead poisoning, ways to protect their children, and property owners' legal responsibility to fix peeling lead paint safely, and increase awareness of regulatory changes and encourage enforcement of New York City's Local Law 1 of 2004. Campaign materials were focus group tested and the campaign was refined annually. The campaign ran city-wide and in targeted high-risk neighborhoods. Neighborhoods and media venue (bus, train, kiosk, and store) changed annually, based on population risk factors and venue availability. Exposure to the campaign, campaign-related knowledge, and behavior were assessed using pre- and postcampaign street intercept surveys. Results showed that campaign reached the targeted population, and had an impact on knowledge of lead poisoning prevention measures as evidenced by increased knowledge of lead paint exposures sources in one year and increased knowledge of preventive behaviors in another year; these improvements were observed for both genders and most ethnic, primary language, educational attainment, and age groups in each year. Lessons learned indicate that well-targeted media campaigns, designed with audience participation, can reach parents through various venues, and improve key knowledge areas. Evaluation challenges faced include high levels of knowledge at baseline, competing media messages, and balancing between program needs and evaluation design.

  3. Embedding of human vertebral bodies leads to higher ultimate load and altered damage localisation under axial compression.

    PubMed

    Maquer, Ghislain; Schwiedrzik, Jakob; Zysset, Philippe K

    2014-01-01

    Computer tomography (CT)-based finite element (FE) models of vertebral bodies assess fracture load in vitro better than dual energy X-ray absorptiometry, but boundary conditions affect stress distribution under the endplates that may influence ultimate load and damage localisation under post-yield strains. Therefore, HRpQCT-based homogenised FE models of 12 vertebral bodies were subjected to axial compression with two distinct boundary conditions: embedding in polymethylmethalcrylate (PMMA) and bonding to a healthy intervertebral disc (IVD) with distinct hyperelastic properties for nucleus and annulus. Bone volume fraction and fabric assessed from HRpQCT data were used to determine the elastic, plastic and damage behaviour of bone. Ultimate forces obtained with PMMA were 22% higher than with IVD but correlated highly (R² = 0.99). At ultimate force, distinct fractions of damage were computed in the endplates (PMMA: 6%, IVD: 70%), cortex and trabecular sub-regions, which confirms previous observations that in contrast to PMMA embedding, failure initiated underneath the nuclei in healthy IVDs. In conclusion, axial loading of vertebral bodies via PMMA embedding versus healthy IVD overestimates ultimate load and leads to distinct damage localisation and failure pattern.

  4. Comparative data on effects of leading pretreatments and enzyme loadings and formulations on sugar

    SciTech Connect

    Wyman, Charles; Balan, Venkatech; Dale, Bruce E.; Elander, Richard; Falls, Matthew; Hames, Bonnie; Holtzapple, Mark; Ladisch, Michael R.; Lee, Y. Y.; Mosier, Nathan; Pallapolu, Venkata R.; Shi, Jian; Warner, Ryan E.

    2011-06-16

    Dilute sulfuric acid (DA), sulfur dioxide (SO2), liquid hot water (LHW), soaking in aqueous ammonia (SAA), ammonia fiber expansion (AFEX), and lime pretreatments were applied to Alamo, Dacotah, and Shawnee switchgrass. Application of the same analytical methods and material balance approaches facil-itated meaningful comparisons of glucose and xylose yields from combined pretreatment and enzymatic hydrolysis. Use of a common supply of cellulase, beta-glucosidase, and xylanase also eased comparisons. All pretreatments enhanced sugar recovery from pretreatment and subsequent enzymatic hydrolysis substantially compared to untreated switchgrass. Adding beta-glucosidase was effective early in enzy-matic hydrolysis while cellobiose levels were high but had limited effect on longer term yields at the enzyme loadings applied. Adding xylanase improved yields most for higher pH pretreatments where more xylan was left in the solids. Harvest time had more impact on performance than switchgrass variety, and microscopy showed changes in different features could impact performance by different pretreatments.

  5. Bioaccessibility, release kinetics, and molecular speciation of arsenic and lead in geo-dusts from the Iron King Mine Federal Superfund site in Humboldt, Arizona.

    PubMed

    Menka, Nazune; Root, Rob; Chorover, Jon

    2014-01-01

    Mine tailings contain multiple toxic metal(loid)s that pose a threat to human health via inhalation and ingestion. The goals of this research include understanding the speciation and molecular environment of these toxic metal(loid)s (arsenic and lead) as well as the impacts particle size and residence time have on their bioaccessibilty in simulated gastric and lung fluid. Additionally, future work will include smaller size fractions (PM10 and PM2.5) of surface mine tailings, with the goal of increasing our understanding of multi-metal release from contaminated geo-dusts in simulated bio-fluids. This research is important to environmental human health risk assessment as it increases the accuracy of exposure estimations to toxic metal(loid)s.

  6. Low-power lead-cooled fast reactor loaded with MOX-fuel

    NASA Astrophysics Data System (ADS)

    Sitdikov, E. R.; Terekhova, A. M.

    2017-01-01

    Fast reactor for the purpose of implementation of research, education of undergraduate and doctoral students in handling innovative fast reactors and training specialists for atomic research centers and nuclear power plants (BRUTs) was considered. Hard neutron spectrum achieved in the fast reactor with compact core and lead coolant. Possibility of prompt neutron runaway of the reactor is excluded due to the low reactivity margin which is less than the effective fraction of delayed neutrons. The possibility of using MOX fuel in the BRUTs reactor was examined. The effect of Keff growth connected with replacement of natural lead coolant to 208Pb coolant was evaluated. The calculations and reactor core model were performed using the Serpent Monte Carlo code.

  7. Modified natural clinoptilolite detoxifies small mammal's organism loaded with lead II: genetic, cell, and physiological effects.

    PubMed

    Topashka-Ancheva, Margarita; Beltcheva, Michaela; Metcheva, Roumiana; Rojas, J Antonio Heredia; Rodriguez-De la Fuente, Abraham O; Gerasimova, Tsvetelina; Rodríguez-Flores, Laura E; Teodorova, Svetla E

    2012-06-01

    The detoxification capacity of the clinoptilolite modification KLS-10-MA used as food additive in small mammals, chronically lead-exposed, was proven for the first time. The modified clinoptilolite was prepared based on natural Bulgarian clinoptilolite deposits. As a powder, it was mechanically mixed at 12.5% concentration with the conventional forage for small rodents. Lead in the form of aqueous solution of Pb(NO(3))(2) was diluted in the drinking water. In the ecotoxicological experiment covering 90 days, imprinting control region laboratory mice were used. They were allocated into four groups: group 1, (control): animals fed with conventional food for small rodents and water; group 2: animals fed with conventional food + clinosorbent KLS-10-MA and water; group 3: animals fed with conventional food and water + Pb(NO(3))(2); and group 4: animals fed with conventional food + KLS-10-MA and water + Pb(NO(3))(2). A group of non-exposed healthy animals was fed with conventional forage mixed with KLS-10-MA to prove eventual toxicity of the sorbent and influence on growth performance. The changes in the chromosome structure, mitotic index, erythrocyte form, erythropoiesis, and body weight gain were recorded. On day 90, the following relations were established: Pb-exposed and clinoptilolite-supplemented mice exhibited 2.3-fold lower chromosome aberrations frequency, 2.5-fold higher mitotic index, and 1.5-fold higher percentage normal erythrocytes 1.3-fold higher body weight compared to Pb-exposed and unsupplemented animals. The obtained data showed that the sorbent is practically non-toxic. The results of the present study encourage a further elaboration of a reliable drug based on the tested substance in the cases of chronic lead intoxication.

  8. Determinants of manganese levels in house dust samples from the CHAMACOS cohort

    PubMed Central

    Gunier, RB; Jerrett, M; Smith, DR; Jursa, T; Yousefi, P; Camacho, J; Hubbard, A; Eskenazi, B; Bradman, A

    2014-01-01

    Introduction Manganese (Mn) is an essential nutrient, but at high exposure levels Mn is a neurotoxicant. The fungicides maneb and mancozeb are approximately 21% Mn by weight and more than 150,000 kg are applied each year to crops in the Salinas Valley, California. It is not clear, however, whether agricultural use of these fungicides increases Mn levels in homes. Materials and methods We collected house dust samples from 378 residences enrolled in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) study with a second sample collected approximately nine months later from 90 of the residences. House dust samples were analyzed for Mn using inductively coupled plasma optical emission spectroscopy. Information from interviews, home inspections, and pesticide use reports was used to identify potential predictors of Mn dust concentrations and loadings. Results Mn was detectable in all dust samples. The median Mn concentration was 171 μg/g and median Mn loading was 1,910 μg/m2 at first visit. In multivariable models, Mn dust concentrations and loadings increased with the number of farmworkers in the home and the amount of agricultural Mn fungicides applied within three kilometers of the residence during the month prior to dust sample collection. Dust concentrations of Mn and other metals (lead, cadmium and chromium) were higher in residences located in the southern Salinas Valley compared those located in other areas of the Salinas Valley. Dust loadings of Mn and other metals were also higher in residences located on Antioch Loam soil than other soil types, and in homes with poor or average housekeeping practices. Conclusions Agricultural use of Mn containing fungicides was associated with Mn dust concentrations and loadings in nearby residences and farmworker homes. Housekeeping practices and soil type at residence were also important factors related to dust metal concentrations and loadings. PMID:25146905

  9. Research, development and demonstration of advanced lead-acid batteries for utility load leveling

    NASA Astrophysics Data System (ADS)

    1983-08-01

    An advanced lead acid storage battery was developed to the preprototype cell and module design stage. Each module is equipped with a low cost tray, automatic watering system, and air-lift pumps for increased acid circulation in each cell. With the qualified alloy catastrophic positive grid corrosion will not limit cell cycle life. An accelerated shallow cycle regime at room ambient tested 60 cell designs for the active material shedding failure mode. It is found that an antishedding active material additive reduces positive active material shedding significantly and extend the cycle life of both the positive and the negative plate. Equations relating cell design to deep cycle life are developed from the factorial tests on the 60 cells.

  10. Increased Cognitive Load Leads to Impaired Mobility Decisions in Seniors at Risk for Falls

    PubMed Central

    Nagamatsu, Lindsay S.; Voss, Michelle; Neider, Mark B.; Gaspar, John G.; Handy, Todd C.; Kramer, Arthur F.; Liu-Ambrose, Teresa Y. L.

    2011-01-01

    Successful mobility requires appropriate decision-making. Seniors with reduced executive functioning— such as senior fallers—may be prone to poor mobility judgments, especially under dual-task conditions. We classified participants as “At-Risk” and “Not-At-Risk” for falls using a validated physiological falls-risk assessment. Dual-task performance was assessed in a virtual reality environment where participants crossed a simulated street by walking on a manual treadmill while listening to music or conversing on a phone. Those “At-Risk” experienced more collisions with oncoming cars and had longer crossing times in the Phone condition compared to controls. We conclude that poor mobility judgments during a dual-task leads to unsafe mobility for those at-risk for falls. PMID:21463063

  11. Aerosol Properties Changes of Northeast Asia due to a Severe Dust Storm in April 2014

    NASA Astrophysics Data System (ADS)

    Fang, Li; Wang, Shupeng; Yu, Tao; Gu, Xingfa; Zhang, Xingying; Wang, Weihe; Ren, Suling

    2016-04-01

    This study focuses on analyzing the aerosol properties changes due to the dust storm named as "China's Great Wall of Dust" oriented from Taklimakan desert in April, 2014. Dust identification IDDI (Infrared Difference Dust Index) images from FY-2E and true color composite images from FY-3C MERSI (Medium Resolution Spectral Imager) show the breakout and transport of the dust storm.From 4-day forward air mass trajectories, the dusty air masses were mostly transported within the lower boundary layer(<3km) over the Northwest China on April 23rd and April 24th, however they were progressively increasing in altitude to above 5km above the surface when they reached the central part of north China region (32°N-42°N; 105°E-123°E). 3-hourly data records at surface stations suggest that anticyclonic circulation occupying southern Xinjiang basin and cyclonic circulation maintaining in Mongolia formed the typical Synoptic condition which leaded to the strong dust storm. Aerosol Index (AI) results of TOU (Total Ozone Unit) aboard FY-3B are first developed and used in studying the affected areas due to the dust storm. The retrieved aerosol indexes show sensitivity to the dust particles. The dust affected areas agree with the synoptic meteorological condition analysis, which prove the synoptic meteorological condition is the main reason for the break out and transport of the dust storm. Anomalies of the average MODIS (Moderate Resolution Imaging Spectroradiometer) AOD (Aerosol Optical Depth) distributions over Northeast Asia during the dust storm to the average of that in April between 2010-2014 show high aerosol loading due to the dust storm. Compared with the 5-year average AOD in April, aerosol loading during this dust storm was much higher, with AOD values at 550nm up to 2.9 observed over the northwest China.The dust storm also brought different change in the aerosol microphysical properties between Beijing and Dalanzadgad. Aerosol Robotic Network (AERONET) retrievals

  12. Testing the sensitivity of past climates to the indirect effects of dust

    NASA Astrophysics Data System (ADS)

    Sagoo, Navjit; Storelvmo, Trude

    2017-06-01

    Mineral dust particles are important ice nuclei (IN) and as such indirectly impact Earth's radiative balance via the properties of cold clouds. Using the Community Earth System Model version 1.0.6, and Community Atmosphere Model version 5.1, and a new empirical parameterization for ice nucleation on dust particles, we investigate the radiative forcing induced by dust IN for different dust loadings. Dust emissions are representative of global conditions for the Last Glacial Maximum and the mid-Pliocene Warm Period. Increased dust leads to smaller and more numerous ice crystals in mixed phase clouds, impacting cloud opacity, lifetime, and precipitation. This increases the shortwave cloud radiative forcing, resulting in significant surface temperature cooling and polar amplification—which is underestimated in existing studies relative to paleoclimate archives. Large hydrological changes occur and are linked to an enhanced dynamical response. We conclude that dust indirect effects could potentially have a significant impact on the model-data mismatch that exists for paleoclimates.Plain Language SummaryMineral <span class="hlt">dust</span> and climate are closely linked, with large fluctuations in <span class="hlt">dust</span> deposition recorded in geological archives. Dusty conditions are generally associated with cold, glacial periods and low <span class="hlt">dust</span> with warmer climates. The direct effects of <span class="hlt">dust</span> on the climate (absorbing and reflecting radiation) are well understood; however, the indirect effects of <span class="hlt">dust</span> on climate have been overlooked. <span class="hlt">Dust</span> indirectly impacts the climate through its role as ice nuclei; the presence of <span class="hlt">dust</span> makes it easier for ice to form in a cloud. We explore the indirect effects of <span class="hlt">dust</span> in climates with different <span class="hlt">dust</span> <span class="hlt">loading</span> from the present by conducting a climate modeling study in which <span class="hlt">dust</span> are able to act as ice nuclei. Including <span class="hlt">dust</span> indirect effects increases the sensitivity of our model to changes in <span class="hlt">dust</span> emission. Increasing <span class="hlt">dust</span> impacts ice</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AtmEn.165...88D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AtmEn.165...88D"><span>Isotopic signatures suggest important contributions from recycled gasoline, road <span class="hlt">dust</span> and non-exhaust traffic sources for copper, zinc and <span class="hlt">lead</span> in PM10 in London, United Kingdom</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dong, Shuofei; Ochoa Gonzalez, Raquel; Harrison, Roy M.; Green, David; North, Robin; Fowler, Geoff; Weiss, Dominik</p> <p>2017-09-01</p> <p>The aim of this study was to improve our understanding of what controls the isotope composition of Cu, Zn and Pb in particulate matter (PM) in the urban environment and to develop these isotope systems as possible source tracers. To this end, isotope ratios (Cu, Zn and Pb) and trace element concentrations (Fe, Al, Cu, Zn, Sb, Ba, Pb, Cr, Ni and V) were determined in PM10 collected at two road sites with contrasting traffic densities in central London, UK, during two weeks in summer 2010, and in potential sources, including non-combustion traffic emissions (tires and brakes), road furniture (road paint, manhole cover and road tarmac surface) and road <span class="hlt">dust</span>. Iron, Ba and Sb were used as proxies for emissions derived from brake pads, and Ni, and V for emissions derived from fossil fuel oil. The isotopic composition of Pb (expressed using 206Pb/207Pb) ranged between 1.1137 and 1.1364. The isotope ratios of Cu and Zn expressed as δ65CuNIST976 and δ66ZnLyon ranged between -0.01‰ and +0.51‰ and between -0.21‰ and +0.33‰, respectively. We did not find significant differences in the isotope signatures in PM10 over the two weeks sampling period and between the two sites, suggesting similar sources for each metal at both sites despite their different traffic densities. The stable isotope composition of Pb suggests significant contribution from road <span class="hlt">dust</span> resuspension and from recycled <span class="hlt">leaded</span> gasoline. The Cu and Zn isotope signatures of tires, brakes and road <span class="hlt">dust</span> overlap with those of PM10. The correlation between the enrichments of Sb, Cu, Ba and Fe in PM10 support the previously established hypothesis that Cu isotope ratios are controlled by non-exhaust traffic emission sources in urban environments (Ochoa Gonzalez et al., 2016). Analysis of the Zn isotope signatures in PM10 and possible sources at the two sites suggests significant contribution from tire wear. However, temporary additional sources, likely high temperature industrial emissions, need to be invoked</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22492856','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22492856"><span>Microwave emission from <span class="hlt">lead</span> zirconate titanate induced by impulsive mechanical <span class="hlt">load</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Aman, A.; Majcherek, S.; Hirsch, S.; Schmidt, B.</p> <p>2015-10-28</p> <p>This paper focuses on microwave emission from <span class="hlt">Lead</span> zirconate titanate Pb [Zr{sub x}Ti{sub 1−x}] O{sub 3} (PZT) induced by mechanical stressing. The mechanical stress was initiated by impact of a sharp tungsten indenter on the upper surface of PZT ceramic. The sequences of microwave and current impulses, which flew from indenter to electric ground, were detected simultaneously. The voltage between the upper and lower surface of ceramic was measured to obtain the behavior of mechanical force acting on ceramic during the impact. It was found that the amplitude, form, and frequency of measured microwave impulses were different by compression and restitution phase of impact. Two different mechanisms of electron emission, responsible for microwave impulse generation, were proposed based on the dissimilar impulse behavior. The field emission from tungsten indenter is dominant during compression, whereas ferroemission dominates during restitution phase. Indeed, it was observed that the direction of the current flow, i.e., sign of current impulses is changed by transitions from compression to restitution phase of impact. The observed dissimilar behavior of microwave impulses, caused by increasing and decreasing applied force, can be used to calculate the contact time and behavior of mechanical force during mechanical impact on ceramic surface. It is shown that the generation of microwave impulses exhibits high reproducibility, impulse intensity, a low damping factor, and high mechanical failure resistance. Based on these microwave emission properties of PZT, the development of new type of stress sensor with spatial resolution of few microns becomes possible.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26125330','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26125330"><span>Comparison of a Wipe Method With and Without a Rinse to Recover Wall Losses in Closed Face 37-mm Cassettes used for Sampling <span class="hlt">Lead</span> <span class="hlt">Dust</span> Particulates.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ceballos, Diana; King, Bradley; Beaucham, Catherine; Brueck, Scott E</p> <p>2015-01-01</p> <p>Closed-face 37-mm polystyrene cassettes are often used for exposure monitoring of metal particulates. Several methods have been proposed to account for the wall loss in air sampling cassettes, including rinsing, wiping, within-cassette dissolution, and an internal capsule fused to the filter that could be digested with the filter. Until internal capsules replace filters, other methods for assessing wall losses may be considered. To determine if rinsing and wiping or wiping alone is adequate to determine wall losses on cassettes, we collected 54 full-shift area air samples at a battery recycling facility. We collected six replicate samples at three locations within the facility for three consecutive days. The wall losses of three replicate cassettes from each day-location were analyzed following a rinse and two consecutive wipes. The wall losses of the other three replicates from each day-location were analyzed following two consecutive wipes only. Mixed-cellulose ester membrane filter, rinse, and wipes were analyzed separately following NIOSH Method 7303. We found an average of 29% (range: 8-54%) recovered <span class="hlt">lead</span> from the cassette walls for all samples. We also found that rinsing prior to wiping the interior cassette walls did not substantially improve recovery of wall losses compared to wiping alone. A rinse plus one wipe recovered on average 23% (range: 13-33%) of the <span class="hlt">lead</span>, while one wipe alone recovered on average 21% (range: 16-22%). Similarly, we determined that a second wipe did not provide substantial additional recovery of <span class="hlt">lead</span> (average: 4%, range: 0.4-19%) compared to the first wipe disregarding the rinse (average: 18%, range: 4-39%). We concluded that when an internal capsule is not used, wall losses of <span class="hlt">lead</span> <span class="hlt">dust</span> in air sampling cassettes can be adequately recovered by wiping the internal wall surfaces of the cassette with a single wipe.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22728800','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22728800"><span>Concentration of <span class="hlt">lead</span>, cadmium, and iron in sediment <span class="hlt">dust</span> and total suspended particles before and after initialisation of integral production in iron and steel work plant Zenica.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Prcanović, Halim; Duraković, Mirnes; Beganović, Sanela</p> <p>2012-06-01</p> <p>Poor air quality is a common fact for all areas with base industry. The city of Zenica was once the metallurgical centre of Ex-Yugoslavia and is therefore highly polluted at present. Air pollution peaked in 1987 when average concentration of pollutants was extremely high (daily average concentration of SO(2) was 1800 μg m(-3)). With the beginning of the war in 1992, integral production in the steel work plant was shut down, to be re-launched in 2008. Limit values for iron do not exist, but iron has been monitored in Zenica for the past 28 years because of the presence of steel works. Concentrations of cadmium and <span class="hlt">lead</span> have also been measured because they are very much present in polluted areas with steel works. The concentration of mentioned elements in air deposit and total suspended particles before and after integral production in the steel work plant was re-launched is the subject of this paper. Total suspended particles were measured in two locations using German standard VDI 2463 Blatt 4. Sediment <span class="hlt">dust</span> was measured in nine locations using Bergerhoff method. The concentration of iron, <span class="hlt">lead</span>, and cadmium was performed in the chemical laboratory of the Metallurgical Institute "Kemal Kapetanović" Zenica using standard methods. Higher concentrations of these parameters during the period of integral production clearly point to the impact of steel works on Zenica valley.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22365753','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22365753"><span><span class="hlt">DUST</span> FORMATION IN MACRONOVAE</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Takami, Hajime; Ioka, Kunihito; Nozawa, Takaya E-mail: kunihito.ioka@kek.jp</p> <p>2014-07-01</p> <p>We examine <span class="hlt">dust</span> formation in macronovae (as known as kilonovae), which are the bright ejecta of neutron star binary mergers and one of the <span class="hlt">leading</span> sites of r-process nucleosynthesis. In light of information about the first macronova candidate associated with GRB 130603B, we find that <span class="hlt">dust</span> grains of r-process elements have difficulty forming because of the low number density of the r-process atoms, while carbon or elements lighter than iron can condense into <span class="hlt">dust</span> if they are abundant. <span class="hlt">Dust</span> grains absorb emission from ejecta with an opacity even greater than that of the r-process elements, and re-emit photons at infrared wavelengths. Such <span class="hlt">dust</span> emission can potentially account for macronovae without r-process nucleosynthesis as an alternative model. This <span class="hlt">dust</span> scenario predicts a spectrum with fewer features than the r-process model and day-scale optical-to-ultraviolet emission.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20130004326','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20130004326"><span>The Martian <span class="hlt">Dust</span> Cycle: Observations and Modeling</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kahre, Melinda A.</p> <p>2013-01-01</p> <p>The <span class="hlt">dust</span> cycle is critically important for Mars' current climate system. Suspended atmospheric <span class="hlt">dust</span> affects the radiative balance of the atmosphere, and thus greatly influences the thermal and dynamical state of the atmosphere. Evidence for the presence of <span class="hlt">dust</span> in the Martian atmosphere can be traced back to yellow clouds telescopically observed as early as the early 19th century. The Mariner 9 orbiter arrived at Mars in November of 1971 to find a planet completely enshrouded in airborne <span class="hlt">dust</span>. Since that time, the exchange of <span class="hlt">dust</span> between the planet's surface and atmosphere and the role of airborne <span class="hlt">dust</span> on Mars' weather and climate has been studied using observations and numerical models. The goal of this talk is to give an overview of the observations and to discuss the successes and challenges associated with modeling the <span class="hlt">dust</span> cycle. <span class="hlt">Dust</span> raising events on Mars range in size from meters to hundreds of kilometers. During some years, regional storms merge to produce hemispheric or planet encircling <span class="hlt">dust</span> clouds that obscure the surface and raise atmospheric temperatures by tens of kelvin. The interannual variability of planet encircling <span class="hlt">dust</span> storms is poorly understood. Although the occurrence and season of large regional and global <span class="hlt">dust</span> storms are highly variable from one year to the next, there are many features of the <span class="hlt">dust</span> cycle that occur year after year. A low-level <span class="hlt">dust</span> haze is maintained during northern spring and summer, while elevated levels of atmospheric <span class="hlt">dust</span> occur during northern autumn and winter. During years without global-scale <span class="hlt">dust</span> storms, two peaks in total <span class="hlt">dust</span> <span class="hlt">loading</span> are generally observed: one peak occurs before northern winter solstice and one peak occurs after northern winter solstice. Numerical modeling studies attempting to interactively simulate the Martian <span class="hlt">dust</span> cycle with general circulation models (GCMs) include the lifting, transport, and sedimentation of radiatively active <span class="hlt">dust</span>. Two <span class="hlt">dust</span> lifting processes are commonly represented in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015RScI...86k3707C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015RScI...86k3707C"><span>Deformation in <span class="hlt">lead</span> zirconate titanate ceramics under large signal electric field <span class="hlt">loading</span> measured by digital image correlation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Di; Kamlah, Marc</p> <p>2015-11-01</p> <p>Digital image correlation, a noncontact and nondestructive method, was employed to monitor the deformation of <span class="hlt">lead</span> zirconate titanate piezoelectric ceramics. This method is based on imaging a speckle pattern on the specimen surface during the test and subsequently correlating each image of the deformed pattern to that in the reference state. In our work, both longitudinal and transverse strains were calculated from imaging a bulk sample under a ±2 kV/mm electric field. Compared with linear variable displacement transducer data, the results from this correlation method were validated. At the same time, based on this optical technique, different strain-electric field butterfly loops can be drawn from correspondingly selected regions of interest. Combined with contour plots of strain on the surface of the sample, the deformation of bulk ceramic sample under uniaxial electric field <span class="hlt">loading</span> without any mechanical constraints is proven to be highly homogenous under macro-observing scale.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26628144','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26628144"><span>Deformation in <span class="hlt">lead</span> zirconate titanate ceramics under large signal electric field <span class="hlt">loading</span> measured by digital image correlation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chen, Di; Kamlah, Marc</p> <p>2015-11-01</p> <p>Digital image correlation, a noncontact and nondestructive method, was employed to monitor the deformation of <span class="hlt">lead</span> zirconate titanate piezoelectric ceramics. This method is based on imaging a speckle pattern on the specimen surface during the test and subsequently correlating each image of the deformed pattern to that in the reference state. In our work, both longitudinal and transverse strains were calculated from imaging a bulk sample under a ±2 kV/mm electric field. Compared with linear variable displacement transducer data, the results from this correlation method were validated. At the same time, based on this optical technique, different strain-electric field butterfly loops can be drawn from correspondingly selected regions of interest. Combined with contour plots of strain on the surface of the sample, the deformation of bulk ceramic sample under uniaxial electric field <span class="hlt">loading</span> without any mechanical constraints is proven to be highly homogenous under macro-observing scale.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002ApPhL..80.4606P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002ApPhL..80.4606P"><span>Measurement of piezoelectric coefficients of <span class="hlt">lead</span> zirconate titanate thin films by strain-monitoring pneumatic <span class="hlt">loading</span> method</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Park, Gun-Tae; Choi, Jong-Jin; Ryu, Jungho; Fan, Huiqing; Kim, Hyoun-Ee</p> <p>2002-06-01</p> <p>A method to simultaneously measure the longitudinal (d33) and transverse (d31) piezoelectric coefficients of a <span class="hlt">lead</span> zirconate titanate (PZT) thin film was developed. This system was based on the pneumatic <span class="hlt">loading</span> method but was modified to monitor the radial strain when a pressurized gas was introduced into the chamber. The results of the bulk piezoelectric material measured by this system coincided with that measured by both the Berlincourt method and the resonance method. The effective d33 and the real d31 of the PZT thin film fabricated by the sol-gel multiple coating method, and poled at 300 kV/cm were 125 and -60 pC/N, respectively. The real d33 estimated upon considering the constraints by the silicon substrate was 180 pC/N.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2006/5188/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2006/5188/"><span>Annual trace-metal <span class="hlt">load</span> estimates and flow-weighted concentrations of cadmium, <span class="hlt">lead</span>, and zinc in the Spokane River basin, Idaho and Washington, 1999-2004</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Donato, Mary M.</p> <p>2006-01-01</p> <p>Streamflow and trace-metal concentration data collected at 10 locations in the Spokane River basin of northern Idaho and eastern Washington during 1999-2004 were used as input for the U.S. Geological Survey software, LOADEST, to estimate annual <span class="hlt">loads</span> and mean flow-weighted concentrations of total and dissolved cadmium, <span class="hlt">lead</span>, and zinc. Cadmium composed less than 1 percent of the total metal <span class="hlt">load</span> at all stations; <span class="hlt">lead</span> constituted from 6 to 42 percent of the total <span class="hlt">load</span> at stations upstream from Coeur d'Alene Lake and from 2 to 4 percent at stations downstream of the lake. Zinc composed more than 90 percent of the total metal <span class="hlt">load</span> at 6 of the 10 stations examined in this study. Trace-metal <span class="hlt">loads</span> were lowest at the station on Pine Creek below Amy Gulch, where the mean annual total cadmium <span class="hlt">load</span> for 1999-2004 was 39 kilograms per year (kg/yr), the mean estimated total <span class="hlt">lead</span> <span class="hlt">load</span> was about 1,700 kg/yr, and the mean annual total zinc <span class="hlt">load</span> was 14,000 kg/yr. The trace-metal <span class="hlt">loads</span> at stations on North Fork Coeur d'Alene River at Enaville, Ninemile Creek, and Canyon Creek also were relatively low. Trace-metal <span class="hlt">loads</span> were highest at the station at Coeur d'Alene River near Harrison. The mean annual total cadmium <span class="hlt">load</span> was 3,400 kg/yr, the mean total <span class="hlt">lead</span> <span class="hlt">load</span> was 240,000 kg/yr, and the mean total zinc <span class="hlt">load</span> was 510,000 kg/yr for 1999-2004. Trace-metal <span class="hlt">loads</span> at the station at South Fork Coeur d'Alene River near Pinehurst and the three stations on the Spokane River downstream of Coeur d'Alene Lake also were relatively high. Differences in metal <span class="hlt">loads</span>, particularly <span class="hlt">lead</span>, between stations upstream and downstream of Coeur d'Alene Lake likely are due to trapping and retention of metals in lakebed sediments. LOADEST software was used to estimate <span class="hlt">loads</span> for water years 1999-2001 for many of the same sites discussed in this report. Overall, results from this study and those from a previous study are in good agreement. Observed differences between the two studies are attributable to streamflow</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AtmEn..39.2201G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AtmEn..39.2201G"><span>Magnetic susceptibility of <span class="hlt">dust-loaded</span> leaves as a proxy of traffic-related heavy metal pollution in Kathmandu city, Nepal</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gautam, Pitambar; Blaha, Ulrich; Appel, Erwin</p> <p></p> <p><span class="hlt">Dust-loaded</span> tree leaves from Kathmandu have been analyzed for magnetic susceptibility ( χ) and heavy metal (HM) contents. For 221 samples of leaves of cypress (mainly Cupressus corneyana), silky oak ( Grevillea robusta) and bottlebrush ( Callistemon lanceolatus), χ has a range of (0.01-54)×10 -8 m 3 kg -1 with a median of about 10.0×10 -8 m 3 kg -1. Trees situated close to the busy road intersections, near the main bus station and sectors of roads with steep slope yield elevated susceptibility. Chemical analysis of 20 samples of varying susceptibility by atomic absorption spectrometry yields the following maximum HM contents: Fe (1.3 wt%), Mn (281.9 ppm), Zn (195.2 ppm), Cu (41.5 ppm), Pb (38.4 ppm), Ni (8.1 ppm), Cr (6.4 ppm), Co (4.1 ppm) and Cd (1.2 ppm). The logarithmic susceptibility on dry mass basis ( χ) shows significant linear relationship with HM contents: Pearson's correlation coefficient r>0.8 with Zn, Fe, Cr; r>0.7 with Mn, Cu; r>0.6 with Pb, Ni. Magnetic phases are of soft (magnetite/maghemite) and hard (hematite) coercivities. Microscopy of magnetic extracts reveals spherules (mostly of 2-20 μm diameter) originated from vehicle exhausts through the combustion process as well as crystalline grains of lithogenic origin. The <span class="hlt">dust</span> accumulation in leaves took place mainly after monsoon (beginning of October 2001) till the sampling period (first half of February 2002). Despite the dependence of susceptibility and HM contents on a variety of spatial and temporal factors (amount of particulate matter (PM), efficiency of deposition/removal of PM by wind, precipitation, birds etc.), a significant correlation of susceptibility to HM implies that the former serves as an effective proxy of metallic pollution. Hence, susceptibility-based bio-monitoring technique is recommended as an economic and rapid tool for assessment of environmental pollution in urban areas like Kathmandu.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..11.7419S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..11.7419S"><span>Understanding the impact of changes in land-use/land-cover and atmospheric <span class="hlt">dust</span> <span class="hlt">loading</span> and their coupling upon climate change in the NEESPI study domain drylands</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sokolik, I.; Darmenova, K.; Darmenov, A.; Xi, X.; Shao, Y.; Marticorena, B.; Bergametti, G.</p> <p>2009-04-01</p> <p>The Northern Eurasia Earth Science Partnership Initiative (NEESPI) Science Plan identifies atmospheric aerosols and pollutions and their impacts on and interactions with the Earth systems (and terrestrial ecosystem dynamics in particular) as a cross-cutting topic of special interest. Wind-blown mineral <span class="hlt">dust</span>, being an important atmospheric constituent in the NEESPI drylands, can exert strong radiative forcing upon the regional climate and cause adverse impacts on human and ecosystems health. The impacts of <span class="hlt">dust</span> storms are not only regional, but may affect areas thousands of kilometers from their source, making interactions between climate change, land use and <span class="hlt">dust</span> aerosols globally relevant. Given the intimate coupling between the land processes and wind-blown atmospheric <span class="hlt">dust</span> and their importance in the climate system, an improved understanding of how land-use/land-cover changes affect Asian <span class="hlt">dust</span> and associated feedbacks is needed to make assessments of climate change more realistic. To improve the ability to predict impacts of <span class="hlt">dust</span> on the climate and environment, we have been developing a coupled regional <span class="hlt">dust</span> modeling system for Central and East Asia. This includes implementation of a new <span class="hlt">dust</span> module DuMo into the NCAR Weather Research and Forecasting (WRF) model as well as a coupled treatment of <span class="hlt">dust</span> aerosol interactions with atmospheric radiation. The <span class="hlt">dust</span> module DuMo includes two different state-of-the art schemes that explicitly account for land properties (including vegetation and soil geomorphology and moisture) and meteorology, and, thus, improves modeling capability. The focus of this talk will be on the impact of atmospheric <span class="hlt">dust</span> on the surface energy balance and photosynthetically active radiation (PAR). Both processes play a key role in the ecosystem functioning as well as overall in land-atmosphere interactions, but they are rarely considered in an integrated fashion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23316077','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23316077"><span>Properties of liquids and <span class="hlt">dusts</span>: how do they influence dermal <span class="hlt">loading</span> during immersion, deposition, and surface contact exposure pathways?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gorman Ng, Melanie; de Poot, Stan; Schmid, Kaspar; Cowie, Hilary; Semple, Sean; van Tongeren, Martie</p> <p>2013-06-01</p> <p>Although dustiness and viscosity are potential determinants of dermal exposure, their effect on exposure is poorly understood. The goal of this study was to investigate the effect of dustiness and viscosity on dermal exposure by each of three dermal exposure pathways (deposition, surface contact, and immersion). The hands of four volunteers were exposed to non-toxic substances: particulate with varying dustiness (calcium acetate, zinc oxide, and Epsom salt) and liquids of varying viscosity (three glycerol/water solutions containing 20, 50, or 85% glycerol) by each pathway. Dermal exposure was measured by a systematic wipe of the entire hand. Calcium acetate, zinc oxide, and Epsom salts were analysed on wipes by inductively coupled plasma/atomic emission spectrometry and glycerol was measured by gas chromatography with a flame ionization detector. The relationship between exposure and either dustiness or viscosity was examined using either parametric (analysis of variance) or non-parametric (Kruskal-Wallis) tests. Both viscosity and dustiness appeared to have an effect on dermal exposure. Increasing viscosity <span class="hlt">lead</span> to higher exposures by the immersion pathway (P < 0.001) but lower exposures by the deposition pathway (although this relationship was not statistically significant: P = 0.19). Viscosity had no apparent effect on exposure from surface contact. Dustiness did not affect transfer of particulate to the skin by immersion (P = 0.403) but it did affect exposure by the surface transfer and deposition pathways. The dustiest substance (calcium acetate) transferred to skin more readily following contact with contaminated surfaces than zinc oxide or Epsom salts (P = 0.016). For the deposition pathway, the highest exposures were seen for the dustiest substance (calcium acetate) but statistical analysis was not conducted as 67% of measurements were below detection limits. The results suggest that both viscosity and dustiness can affect dermal exposure. They also show</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20605620','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20605620"><span>Application of the Nernst-Planck approach to <span class="hlt">lead</span> ion exchange in Ca-<span class="hlt">loaded</span> Pelvetia canaliculata.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Costa, Joana F de Sá S; Vilar, Vítor J P; Botelho, Cidália M S; da Silva, Eduardo A B; Boaventura, Rui A R</p> <p>2010-07-01</p> <p>Ca-<span class="hlt">loaded</span> Pelvetia canaliculata biomass was used to remove Pb(2+) in aqueous solution from batch and continuous systems. The physicochemical characterization of algae Pelvetia particles by potentiometric titration and FTIR analysis has shown a gel structure with two major binding groups - carboxylic (2.8 mmol g(-1)) and hydroxyl (0.8 mmol g(-1)), with an affinity constant distribution for hydrogen ions well described by a Quasi-Gaussian distribution. Equilibrium adsorption (pH 3 and 5) and desorption (eluents: HNO(3) and CaCl(2)) experiments were performed, showing that the biosorption mechanism was attributed to ion exchange among calcium, <span class="hlt">lead</span> and hydrogen ions with stoichiometry 1:1 (Ca:Pb) and 1:2 (Ca:H and Pb:H). The uptake capacity of <span class="hlt">lead</span> ions decreased with pH, suggesting that there is a competition between H(+) and Pb(2+) for the same binding sites. A mass action law for the ternary mixture was able to predict the equilibrium data, with the selectivity constants alpha(Ca)(H)=9+/-1 and alpha(Ca)(Pb)=44+/-5, revealing a higher affinity of the biomass towards <span class="hlt">lead</span> ions. Adsorption (initial solution pH 4.5 and 2.5) and desorption (0.3M HNO(3)) kinetics were performed in batch and continuous systems. A mass transfer model using the Nernst-Planck approximation for the ionic flux of each counter-ion was used for the prediction of the ions profiles in batch systems and packed bed columns. The intraparticle effective diffusion constants were determined as 3.73x10(-7)cm(2)s(-1) for H(+), 7.56x10(-8)cm(2)s(-1) for Pb(2+) and 6.37x10(-8)cm(2)s(-1) for Ca(2+). Copyright 2010 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19910005676','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19910005676"><span>Galaxy formation by <span class="hlt">dust</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wang, Boqi; Field, Goerge B.</p> <p>1989-01-01</p> <p>It has been known since the early 1940's that radiation can cause an instability in the interstellar medium. Absorbing <span class="hlt">dust</span> 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, <span class="hlt">leading</span> 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 <span class="hlt">dust</span>, instability in the <span class="hlt">dust</span> distribution caused by mock gravity may have led to the formation of galaxies and galaxy clusters. In their picture of a well-coupled <span class="hlt">dust</span>-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 <span class="hlt">dust</span>, and infrared reemission which is subsequently redshifted. HW's analysis omits radiative drag, incomplete collisional coupling of gas and <span class="hlt">dust</span>, finite <span class="hlt">dust</span> 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 <span class="hlt">dust</span> is more rapid than that of the gas. Moreover, since the <span class="hlt">dust</span> moves with supersonic velocity through the gas soon after the perturbation becomes optically thin, the sputtering of <span class="hlt">dust</span> particles by gas is significant, so the <span class="hlt">dust</span> could disappear before the instability develops significantly. They conclude that the mock gravity by <span class="hlt">dust</span> is not important in galaxy formations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19990053994&hterms=Combustible&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DCombustible','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990053994&hterms=Combustible&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DCombustible"><span>Laminar <span class="hlt">Dust</span> Flames: A Program of Microgravity and Ground Based Studies at McGill</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Goroshin, Sam; Lee, John</p> <p>1999-01-01</p> <p>Fundamental knowledge of heterogeneous combustion mechanisms is required to improve utilization of solid fuels (e.g. coal), safe handling of combustible <span class="hlt">dusts</span> in industry, and solid propulsion systems. The objective of the McGill University research program on <span class="hlt">dust</span> combustion is to obtain a reliable set of data on basic combustion parameters for <span class="hlt">dust</span> suspensions (i.e. laminar burning velocity, flame structure, quenching distance, flammability limits, etc.) over a range of particle sizes, <span class="hlt">dust</span> concentrations, and types of fuel. This set of data then permits theoretical models to be validated and, when necessary, new models to be developed to describe the detailed reaction mechanisms and transport processes. Microgravity is essential to the generation of a uniform <span class="hlt">dust</span> suspension of arbitrary particle size and concentration. When particles with a characteristic size on the order of tens of microns are suspended, they rapidly settle in a gravitational field. To maintain a particulate in suspension for time duration adequate to carry out combustion experiments invariably requires continuous convective flow in excess of the gravitational settling velocity (which is comparable with and can even exceed the <span class="hlt">dust</span> laminar burning velocity). This makes the experiments turbulent in nature and thus renders it impossible to study laminar <span class="hlt">dust</span> flames. Even for small particle sizes on the order of microns, a stable laminar <span class="hlt">dust</span> flow can be maintained only for relatively low <span class="hlt">dust</span> concentrations at normal gravity conditions. High <span class="hlt">dust</span> <span class="hlt">loading</span> <span class="hlt">leads</span> to gravitational instability of the <span class="hlt">dust</span> cloud and to the formation of recirculation cells in the <span class="hlt">dust</span> suspension in a confined volume, or to the rapid sedimentation of the dense <span class="hlt">dust</span> cloud, as a whole, in an unconfined volume. Many important solid fuels such as carbon and boron also have low laminar flame speeds (of the order of several centimeters per second). Convection that occurs in combustion products due to buoyancy disrupts the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.P41C1937K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.P41C1937K"><span>Temperature and <span class="hlt">dust</span> profiles in Martian <span class="hlt">dust</span> storm conditions retrieved from Mars Climate Sounder measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kleinboehl, A.; Kass, D. M.; Schofield, J. T.; McCleese, D. J.</p> <p>2013-12-01</p> <p>Mars Climate Sounder (MCS) is a mid- and far-infrared thermal emission radiometer on board the Mars Reconnaissance Orbiter. It measures radiances in limb and nadir/on-planet geometry from which vertical profiles of atmospheric temperature, water vapor, <span class="hlt">dust</span> and condensates can be retrieved in an altitude range from 0 to 80 km and with a vertical resolution of ~5 km. Due to the limb geometry used as the MCS primary observation mode, retrievals in conditions with high aerosol <span class="hlt">loading</span> are challenging. We have developed several modifications to the MCS retrieval algorithm that will facilitate profile retrievals in high-<span class="hlt">dust</span> conditions. Key modifications include a retrieval option that uses a surface pressure climatology if a pressure retrieval is not possible in high <span class="hlt">dust</span> conditions, an extension of aerosol retrievals to higher altitudes, and a correction to the surface temperature climatology. In conditions of a global <span class="hlt">dust</span> storm, surface temperatures tend to be lower compared to standard conditions. Taking this into account using an adaptive value based on atmospheric opacity <span class="hlt">leads</span> to improved fits to the radiances measured by MCS and improves the retrieval success rate. We present first results of these improved retrievals during the global <span class="hlt">dust</span> storm in 2007. Based on the limb opacities observed during the storm, retrievals are typically possible above ~30 km altitude. Temperatures around 240 K are observed in the middle atmosphere at mid- and high southern latitudes after the onset of the storm. <span class="hlt">Dust</span> appears to be nearly homogeneously mixed at lower altitudes. Significant <span class="hlt">dust</span> opacities are detected at least up to 70 km altitude. During much of the storm, in particular at higher altitudes, the retrieved <span class="hlt">dust</span> profiles closely resemble a Conrath-profile.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRD..122.8233X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRD..122.8233X"><span>Sense size-dependent <span class="hlt">dust</span> <span class="hlt">loading</span> and emission from space using reflected solar and infrared spectral measurements: An observation system simulation experiment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, Xiaoguang; Wang, Jun; Wang, Yi; Henze, Daven K.; Zhang, Li; Grell, Georg A.; McKeen, Stuart A.; Wielicki, Bruce A.</p> <p>2017-08-01</p> <p>The Climate Absolute Radiance and Refractivity Observatory (CLARREO) satellite mission observes hyperspectral Earth reflected solar (RS) and emitted infrared radiance (IR). Such measurements span an additional dimension on spectrally dependent scattering and absorption of <span class="hlt">dust</span>, the critical signals for particle size. Through a suite of observation system simulation experiments (OSSEs), this study assesses the capability of CLARREO's measurements for recovering size-dependent <span class="hlt">dust</span> emissions in GEOS-Chem chemistry transport model (CTM). To this end, another CTM (Flow-following finite-volume Icosahedral Model-Chem, or FIM-Chem) is used for the nature run to simulate CLARREO spectral radiances. The spectral signals are then used for analyzing the sensitivities and error characteristics of <span class="hlt">dust</span> optical depth (DOD) under three observations scenarios (IR only, RS only, and combined IR and RS) using an optimal estimation technique. Next, these synthetic data are assimilated into GEOS-Chem adjoint model to constrain <span class="hlt">dust</span> emissions of four particle sizes with radii from 0.1 μm to 6.0 μm. The OSSEs results indicate (1) the IR spectra are most sensitive to <span class="hlt">dust</span> of the third size bin (1.8-3.0 μm) and least sensitive to the smallest bin (0.1-1.0 μm); (2) the RS spectra are most sensitive to <span class="hlt">dust</span> of the smallest size bin and the sensitivity decreases as <span class="hlt">dust</span> size increases; (3) combining IR and RS spectra can fully characterize DOD across all sizes, providing the best constraints for size-resolved <span class="hlt">dust</span> emissions; and (4) CLARREO data fail to constrain the spatial distribution of <span class="hlt">dust</span> sources due to its narrow swath and joint observations from CLARREO-calibrated sensors with wide swath are desirable.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19770021168','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19770021168"><span><span class="hlt">Load</span> and stability measurements on a soft-inplane rotor system incorporating elastomeric <span class="hlt">lead</span>-lag dampers</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Weller, W. H.</p> <p>1977-01-01</p> <p>An experimental investigation was conducted of the dynamic response and inplane stability associated with a new soft-inplane helicopter rotor. The unique feature of this rotor was the use of an internal elastomeric damper to restrain the blade inplane motion about the <span class="hlt">lead</span>-lag hinge. The properties of the elastomer were selected to provide both a nominal first inplane frequency ratio of 0.65 and sufficient damping to eliminate the need for additional external damping sources to prevent ground resonance on a typical fuselage structure. For this investigation a 1/5-scale aeroelastic model was used to represent the rotor. The four-blade model had a diameter of 3.05 m (10 ft) and a solidity of 0.103. The first out-of-plane frequency ratio was 1.06. The model was tested in hover and in forward flight up to an advance ratio of 0.45. At each forward speed the rotor lift was varied up to simulated maneuver conditions. The measured rotor <span class="hlt">loads</span> and response were within acceptable limits, and no adverse response qualities were observed. Moderate out-of-plane hub moments were measured, even for zero lift, to indicate the beneficial control power available for this design. Blade inplane stability testing indicated that the rotor system damping remained at moderate levels throughout the operating envelope.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28126477','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28126477"><span>Highly efficient and selective removal of trace <span class="hlt">lead</span> from aqueous solutions by hollow mesoporous silica <span class="hlt">loaded</span> with molecularly imprinted polymers.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Zulei; Zhang, Xingdi; Niu, Dechao; Li, Yongsheng; Shi, Jianlin</p> <p>2017-04-15</p> <p>A novel type of adsorbent for the selective recognition and adsorption of trace Pb(2+) from aqueous solutions has been successfully constructed simply by grafting molecularly imprinted polymers (MIPs) onto hollow mesoporous silica (HMS). Attractively, the HMS <span class="hlt">loaded</span> with MIPs (H-MIPs) exhibits a fast adsorption kinetics, marked adsorption capacity of 40.52mg/g and extremely high selectivity toward Pb(2+) over Cu(2+), Zn(2+), Co(2+), Mn(2+) and Ni(2+), and the selectivity coefficients have been determined to be as high as 50. Moreover, such high adsorptive capability and selectivity were retained for at least 6 runs, indicating the stability and reusability of H-MIPs. <span class="hlt">Lead</span> ion contaminants in real water samples were successfully concentrated and approximately 100% recovered using H-MIPs. Theoretical analysis shows that the adsorption process of H-MIPs follows the pseudo-second-order kinetic and Langmuir isotherm models. These demonstrate that H-MIPs are greatly potential for the rapid and highly efficient removal of trace Pb(2+) ions in complicated matrices.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2000/0441/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2000/0441/report.pdf"><span>Concentrations and <span class="hlt">loads</span> of cadmium, <span class="hlt">lead</span>, zinc, and nutrients measured during the 1999 water year within the Spokane River basin, Idaho and Washington</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Woods, P.F.</p> <p>2001-01-01</p> <p>the network was to quantify the absolute and relative magnitude of hydrologic, trace-element, and nutrient <span class="hlt">loads</span> transported by numerous stream reaches within the Spokane River Basin. Of the 29 water-quality stations in the network, 19 were in the Coeur d?Alene River Basin, 2 were in the St. Joe River Basin, and the remaining 8 were on the Spokane River downstream from Coeur d'Alene Lake. All stations were sampled for whole-water recoverable and dissolved concentrations of cadmium, <span class="hlt">lead</span>, and zinc. Nitrogen and phosphorus concentrations were sampled at nine stations to determine <span class="hlt">loads</span> of nutrients into and out of Coeur d'Alene Lake and transported down the Spokane River into the Columbia River. Mean daily discharge during the 1999 water year was about 120 percent of the long-term average. Trace-element <span class="hlt">loads</span> to the Columbia River were calculated for the basin's terminal station, Spokane River at Long Lake. For whole-water recoverable cadmium, 2,110 pounds, 92 percent of which was dissolved, was delivered to the Columbia River. The Columbia River received 25,000 pounds of whole-water recoverable <span class="hlt">lead</span>, 29 percent of which was dissolved, from the Spokane River Basin. The largest trace-element <span class="hlt">load</span> delivered to the Columbia River by the Spokane River was 764,000 pounds of whole-water recoverable zinc, 76 percent of which was dissolved. The primary source of trace-element <span class="hlt">loads</span> in the Spokane River Basin was the Coeur d'Alene River Basin. The South Fork Coeur d'Alene River was the largest source of dissolved and wholewater recoverable <span class="hlt">loads</span> of cadmium and zinc. In contrast, the main stem of the Coeur d'Alene River was the largest source of dissolved and wholewater recoverable <span class="hlt">loads</span> of <span class="hlt">lead</span>. Within the South Fork, substantial increases in dissolved <span class="hlt">loads</span> of cadmium, <span class="hlt">lead</span>, and zinc were detected in excess of those measured by the monitoring network stations upstream from the terminal station, South Fork Coeur d'Alene River near Pinehurst. Much of the added <span class="hlt">load</span> was</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A31A3011L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A31A3011L"><span>Evaluating NCEP Global <span class="hlt">Dust</span> Forecasts using VIIRS <span class="hlt">Dust</span> Mask Index and VIIRS Aerosol Observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lu, C. H.; Ciren, P.; Kondragunta, S.; Wang, J.; Bhattacharjee, P. S.</p> <p>2014-12-01</p> <p>NOAA/NCEP recently implemented NASA's Goddard Global Ozone Chemistry Aerosol Radiation and Transport model (GOCART) into Global Forecast System (GFS) and the resulting global aerosol forecasting system (called NGAC) has the capability to simulate <span class="hlt">dust</span>, sulfate, sea salt, and carbonaceous aerosols. A real-time <span class="hlt">dust</span>-only NGAC has been operational since September 2012. Evaluation of NGAC <span class="hlt">dust</span> forecast for the summer 2013 utilizes Visible Infrared Imaging Radiometer Suite (VIIRS) AOD retrievals and VIIRS <span class="hlt">dust</span> mask index. While AOD retrievals are quantitative indicating column atmospheric aerosol <span class="hlt">loading</span>, <span class="hlt">dust</span> mask index is a qualitative flag indicating the presence of <span class="hlt">dust</span> and <span class="hlt">dust</span> intensity in the atmosphere. The combination of <span class="hlt">dust</span> flag and AOD from VIIRS enables the comparison between NGAC <span class="hlt">dust</span> AOD versus VIIRS <span class="hlt">dust</span> AOD. The performance NGAC will be evaluated with these comparisons on a global and regional scales near and downwind of <span class="hlt">dust</span> sources.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930009365','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930009365"><span>Cosmic <span class="hlt">dust</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Brownlee, Donald E.; Sandford, Scott A.</p> <p>1992-01-01</p> <p><span class="hlt">Dust</span> is a ubiquitous component of our galaxy and the solar system. The collection and analysis of extraterrestrial <span class="hlt">dust</span> 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 <span class="hlt">dust</span>; the carbonaceous component of interplanetary <span class="hlt">dust</span> particles; and the presence of an interstellar component.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eosweb.larc.nasa.gov/project/misr/gallery/dust_storm_aus','SCIGOV-ASDC'); return false;" href="https://eosweb.larc.nasa.gov/project/misr/gallery/dust_storm_aus"><span><span class="hlt">Dust</span> Storm</span></a></p> <p><a target="_blank" href="http://eosweb.larc.nasa.gov/">Atmospheric Science Data Center </a></p> <p></p> <p>2013-04-16</p> <p>article title:  Massive <span class="hlt">Dust</span> Storm over Australia     View ... at JPL September 22, 2009 - Massive <span class="hlt">dust</span> storm over Australia. project:  MISR category:  ... Sep 22, 2009 Images:  <span class="hlt">Dust</span> Storm location:  Australia and New Zealand ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120011111','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120011111"><span>Coupling Mars' <span class="hlt">Dust</span> and Water Cycles: Effects on <span class="hlt">Dust</span> Lifting Vigor, Spatial Extent and Seasonality</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kahre, M. A.; Hollingsworth, J. L.; Haberle, R. M.; Montmessin, F.</p> <p>2012-01-01</p> <p>The <span class="hlt">dust</span> cycle is an important component of Mars' current climate system. Airborne <span class="hlt">dust</span> affects the radiative balance of the atmosphere, thus greatly influencing the thermal and dynamical state of the atmosphere. <span class="hlt">Dust</span> raising events on Mars occur at spatial scales ranging from meters to planet-wide. Although the occurrence and season of large regional and global <span class="hlt">dust</span> storms are highly variable from one year to the next, there are many features of the <span class="hlt">dust</span> cycle that occur year after year. Generally, a low-level <span class="hlt">dust</span> haze is maintained during northern spring and summer, while elevated levels of atmospheric <span class="hlt">dust</span> occur during northern autumn and winter. During years without global-scale <span class="hlt">dust</span> storms, two peaks in total <span class="hlt">dust</span> <span class="hlt">loading</span> were observed by MGS/TES: one peak occurred before northern winter solstice at Ls 200-240, and one peak occurred after northern winter solstice at L(sub s) 305-340. These maxima in <span class="hlt">dust</span> <span class="hlt">loading</span> are thought to be associated with transient eddy activity in the northern hemisphere, which has been observed to maximize pre- and post-solstice. Interactive <span class="hlt">dust</span> cycle studies with Mars General Circulation Models (MGCMs) have included the lifting, transport, and sedimentation of radiatively active <span class="hlt">dust</span>. Although the predicted global <span class="hlt">dust</span> <span class="hlt">loadings</span> from these simulations capture some aspects of the observed <span class="hlt">dust</span> cycle, there are marked differences between the simulated and observed <span class="hlt">dust</span> cycles. Most notably, the maximum <span class="hlt">dust</span> <span class="hlt">loading</span> is robustly predicted by models to occur near northern winter solstice and is due to <span class="hlt">dust</span> lifting associated with down slope flows on the flanks of the Hellas basin. Thus far, models have had difficulty simulating the observed pre- and post- solstice peaks in <span class="hlt">dust</span> <span class="hlt">loading</span>. Interactive <span class="hlt">dust</span> cycle studies typically have not included the formation of water ice clouds or their radiative effects. Water ice clouds can influence the <span class="hlt">dust</span> cycle by scavenging <span class="hlt">dust</span> from atmosphere and by interacting with solar and infrared radiation</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999JPS....78..171H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999JPS....78..171H"><span>Operational experience and performance characteristics of a valve-regulated <span class="hlt">lead</span>-acid battery energy-storage system for providing the customer with critical <span class="hlt">load</span> protection and energy-management benefits at a <span class="hlt">lead</span>-recycling plant</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hunt, G. W.</p> <p></p> <p>The Power Control Division of GNB Technologies, commissioned on May 13, 1996 a new facility which houses a 5-MW battery energy-storage system (BESS) at GNB's <span class="hlt">Lead</span> Recycling Centre in Vernon, CA. When the plant loses utility power (which typically happens two or three times a year), the BESS will provide up to 5 MW of power at 4160 VAC in support of all the plant <span class="hlt">loads</span>. Since the critical <span class="hlt">loads</span> are not isolated, it is necessary to carry the entire plant <span class="hlt">load</span> (maximum of 5 MVA) for a short period immediately following an incident until non-critical <span class="hlt">loads</span> have been automatically shed. Plant <span class="hlt">loading</span> typically peaks at 3.5 MVA with critical <span class="hlt">loads</span> of about 2.1 MVA. The BESS also provides the manufacturing plant with customer-side-of-the-meter energy management options to reduce its energy demand during peak periods of the day. The BESS has provided a reduction in monthly electric bills through daily peak-shaving. By design, the battery can provide up to 2.5 MWh of energy and still retain 2.5 MWh of capacity in reserve to handle the possibility of a power outage in protecting the critical <span class="hlt">loads</span> for up to 1 h. By storing energy from the utility during off-peak hours of the night in the batteries when the cost is low (US4.5¢ per kWh), GNB can then discharge this energy during high demand periods of the day (US14.50 per kW). For example, by reducing its peak demand by 300 kW, the <span class="hlt">lead</span>-recycling centre can save over US4000 per month in its electric bills. The BESS at Vernon represents a first large-scale use of valve-regulated <span class="hlt">lead</span>-acid batteries in such a demanding application. This paper presents a summary of the operational experience and performance characteristics of the BESS over the past 2 years.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22039832','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22039832"><span>Highly <span class="hlt">lead-loaded</span> red plastic scintillators as an X-ray imaging system for the Laser Mega Joule</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hamel, M.; Normand, S.; Turk, G.; Darbon, S.</p> <p>2011-07-01</p> <p>The scope of this project intends to record spatially resolved images of core shape and size of a DT micro-balloon during Inertial Confinement Fusion (ICF) experiments at Laser Mega Joule facility (LMJ). We need to develop an X-ray imaging system which can operate in the radiative background generated by an ignition shot of ICF. The scintillator is a part of the imaging system and has to gather a compromise of scintillating properties (scintillating efficiency, decay time, emission wavelength) so as to both operate in the hard radiative environment and to allow the acquisition of spatially resolved images. Inorganic scintillators cannot be used because no compromise can be found regarding the expected scintillating properties, most of them are not fast enough and emit blue light. Organic scintillators are generally fast, but present low X-ray absorption in the 10 to 40 keV range, that does not permit the acquisition of spatially resolved images. To this aim, we have developed highly <span class="hlt">lead-loaded</span> and red-fluorescent fast plastic scintillators. Such a combination is not currently available via scintillator suppliers, since they propose only blue-fluorescent plastic scintillators doped with up to 12%w Pb. Thus, incorporation ratio up to 27%w Pb has been reached in our laboratory, which can afford a plastic scintillator with an outstanding Z{sub eff} close to 50. X-rays in the 10 to 40 keV range can thus be detected with a higher probability of photoelectric effect than for classic organic scintillators, such as NE102. The strong orange-red fluorescence can be filtered, so that we can eliminate residual Cerenkov light, generated by {gamma}-ray absorption in glass parts of the imaging system. Decay times of our scintillators evaluated under UV excitation were estimated to be in the range 10 to 13 ns. (authors)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AtmEn.161...82D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AtmEn.161...82D"><span>Applying geochemical signatures of atmospheric <span class="hlt">dust</span> to distinguish current mine emissions from legacy sources</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dong, Chenyin; Taylor, Mark Patrick</p> <p>2017-07-01</p> <p>Resolving the source of environmental contamination is the critical first step in remediation and exposure prevention. Australia's oldest silver-zinc-<span class="hlt">lead</span> mine at Broken Hill (>130 years old) has generated a legacy of contamination and is associated with persistent elevated childhood blood <span class="hlt">lead</span> (Pb) levels. However, the source of environmental Pb remains in dispute: current mine emissions; remobilized mine-legacy <span class="hlt">lead</span> in soils and <span class="hlt">dusts</span>; and natural <span class="hlt">lead</span> from geological weathering of the gossan ore body. Multiple lines of evidence used to resolve this conundrum at Broken Hill include spatial and temporal variations in <span class="hlt">dust</span> Pb concentrations and bioaccessibility, Pb isotopic compositions, particle morphology and mineralogy. Total <span class="hlt">dust</span> Pb <span class="hlt">loading</span> (mean 255 μg/m2/day) and its bioaccessibility (mean 75% of total Pb) is greatest adjacent to the active mining operations. Unweathered galena (PbS) found in contemporary <span class="hlt">dust</span> deposits contrast markedly to Pb-bearing particles from mine-tailings and weathered gossan samples. Contemporary <span class="hlt">dust</span> particles were more angular, had higher sulfur content and had little or no iron and manganese. <span class="hlt">Dust</span> adjacent to the mine has Pb isotopic compositions (208Pb/207Pb: 2.3197; 206Pb/207Pb: 1.0406) that are a close match (99%) to the ore body with values slightly lower (94%) at the edge of the city. The weight of evidence supports the conclusion that contemporary <span class="hlt">dust</span> Pb contamination in Broken Hill is sourced primarily from current mining activities and not from weathering or legacy sources.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19860014030','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19860014030"><span>Circumstellar <span class="hlt">dust</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dwek, E.</p> <p>1986-01-01</p> <p>The presence of <span class="hlt">dust</span> 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 <span class="hlt">dust</span> must therefore be present for <span class="hlt">dust</span> 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 <span class="hlt">dust</span> in the various sources; (2) examine the clues to the nature and composition of the <span class="hlt">dust</span>; (3) review the status of grain formation theories; (4) examine any evidence for the processing of the <span class="hlt">dust</span> prior to its injection into the interstellar medium; and (5) estimate the relative contribution of the various sources to the interstellar <span class="hlt">dust</span> population.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19960008407','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19960008407"><span>Microgravity combustion of <span class="hlt">dust</span> clouds: Quenching distance measurements</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Goroshin, S.; Kleine, H.; Lee, J. H. S.; Frost, D.</p> <p>1995-01-01</p> <p>The current level of physical understanding of <span class="hlt">dust</span> combustion phenomena is still in a rudimentary state compared with the understanding of gas combustion processes. The reason for such a lack of fundamental understanding is partially based on the complexity of multiphase combustion and the enormous diversity of chemical-physical properties of heterogeneous combustible mixtures but is largely due to difficulties in the experimental investigation of <span class="hlt">dust</span> combustion. The influence of gravity on a <span class="hlt">dust</span> suspension is the main reason. First of all, when particulates (either solid particles or liquid droplets) with a characteristic size of the order of tens of microns are suspended, they rapidly settle in the gravitational field. To maintain a particulate suspension for a time duration adequate to carry out combustion experiments invariably requires continuous convection of particulates at or in excess of the gravitational settling velocity. Of necessity, this makes the experiments turbulent in character and makes it impossible to study laminar <span class="hlt">dust</span> flames. For particle sizes of the order of microns a stable laminar <span class="hlt">dust</span> flow can be maintained only for relatively small <span class="hlt">dust</span> concentrations (e.g., for low fuel equivalence ratios) at normal gravity conditions. High <span class="hlt">dust</span> <span class="hlt">loading</span> <span class="hlt">leads</span> to gravitational instability of the <span class="hlt">dust</span> cloud and to the formation of recirculation cells in a <span class="hlt">dust</span> suspension in a confined volume, or to the rapid sedimentation of the dense <span class="hlt">dust</span> cloud as a whole in an unconfined volume. In addition, many important solid fuels such as low volatile coal, carbon, and boron have low laminar flame speeds (of the order of several centimeters per second). Gravitational convection that occurs in combustion products due to the buoyancy forces disrupts low speed <span class="hlt">dust</span> flames and, therefore, makes observation of such flames at normal gravity impossible. The only way to carry out 'clean' fundamental experiments in <span class="hlt">dust</span> combustion over a wide range of <span class="hlt">dust</span> cloud</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=335532&keyword=text+AND+mining&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=335532&keyword=text+AND+mining&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>Estimating Children’s Soil/<span class="hlt">Dust</span> Ingestion Rates through Retrospective Analyses of Blood <span class="hlt">Lead</span> Biomonitoring from the Bunker Hill Superfund Site in Idaho</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Background: Soil/<span class="hlt">dust</span> ingestion rates are important variables in assessing children’s health risks in contaminated environments. Current estimates are based largely on soil tracer methodology, which is limited by analytical uncertainty, small sample size, and short study du...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=335532&keyword=day&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=91070945&CFTOKEN=30081522','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=335532&keyword=day&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=91070945&CFTOKEN=30081522"><span>Estimating Children’s Soil/<span class="hlt">Dust</span> Ingestion Rates through Retrospective Analyses of Blood <span class="hlt">Lead</span> Biomonitoring from the Bunker Hill Superfund Site in Idaho</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Background: Soil/<span class="hlt">dust</span> ingestion rates are important variables in assessing children’s health risks in contaminated environments. Current estimates are based largely on soil tracer methodology, which is limited by analytical uncertainty, small sample size, and short study du...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010cosp...38.3645K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010cosp...38.3645K"><span>Lunar <span class="hlt">Dust</span> Mitigation Screens</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Knutson, Shawn; Holloway, Nancy</p> <p></p> <p>With plans for the United States to return to the moon, and establish a sustainable human presence on the lunar surface many issues must be successfully overcome. Lunar <span class="hlt">dust</span> is one of a number of issues with the potential to create a myriad of problems if not adequately addressed. Samples of <span class="hlt">dust</span> brought back from Apollo missions show it to be soft, yet sharp and abrasive. The <span class="hlt">dust</span> consists of a variety of morphologies including spherical, angular blocks, shards, and a number of irregular shapes. One of the main issues with lunar <span class="hlt">dust</span> is its attraction to stick to anything it comes in contact with (i.e. astronauts, equipment, habitats, etc.). Ionized radiation from the sun strikes the moon's surface and creates an electrostatic charge on the <span class="hlt">dust</span>. Further, the <span class="hlt">dust</span> harbors van der Waals forces making it especially difficult to separate once it sticks to a surface. During the Apollo missions, it was discovered that trying to brush the lunar <span class="hlt">dust</span> from spacesuits was not effective, and rubbing it caused degradation of the suit material. Further, when entering the lunar module after moonwalks, the astronauts noted that the <span class="hlt">dust</span> was so prolific inside the cabin that they inhaled and ingested it, causing at least one of them, Harrison "Jack" Schmidt, to report irritation of the throat and lungs. It is speculated that the <span class="hlt">dust</span> could also harm an astronaut's nervous and cardiovascular systems, especially during an extended stay. In addition to health issues, the <span class="hlt">dust</span> can also cause problems by scouring reflective coatings off of thermal blankets, and roughening surfaces of windows and optics. Further, panels on solar cells and photovoltaics can also be compromised due to <span class="hlt">dust</span> sticking on the surfaces. Lunar <span class="hlt">dust</span> has the capacity to penetrate seals, interfere with connectors, as well as mechanisms on digging machines, all of which can <span class="hlt">lead</span> to problems and failure. To address lunar <span class="hlt">dust</span> issues, development of electrostatic screens to mitigate <span class="hlt">dust</span> on sur-faces is currently</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26235514','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26235514"><span>Does increasing applied <span class="hlt">load</span> <span class="hlt">lead</span> to contact changes indicative of knee osteoarthritis? A subject-specific FEA study.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Boyd, Jennifer L; Zavatsky, Amy B; Gill, Harinderjit S</p> <p>2016-04-01</p> <p>This study investigated whether increased <span class="hlt">loading</span> (representing obesity) in the extended knee and flexed knee led to increased stresses in areas of typical medial and lateral osteoarthritis cartilage lesions, respectively. We created two paired sets of subject-specific finite element models; both sets included models of extended knees and of flexed knees. The first set represented normal <span class="hlt">loading</span>; the second set represented increased <span class="hlt">loading</span>. All other variables were held constant. The von Mises stresses and contact areas calculated on the tibial cartilage surfaces of the paired models were then compared. In the extended knee models, applying a larger <span class="hlt">load</span> led to increased stress in the anterior and central regions of the medial tibial cartilage. These are the typical locations of medial osteoarthritis cartilage lesions. Therefore, the results support that increased <span class="hlt">loading</span> in the extended knee may result in medial osteoarthritis. In the flexed knee models, applying a larger <span class="hlt">load</span> increased stress in the anterior and central regions of the lateral tibial cartilage. Lateral osteoarthritis cartilage lesions typically occur centrally and posteriorly. Therefore, these results do not support our hypothesis. Shear stress was increased in areas of typical lateral lesions, however, and should be investigated in future studies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015toru.conf..F02P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015toru.conf..F02P"><span>Comments on <span class="hlt">Dust</span> Reverberation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Peterson, B.</p> <p>2015-09-01</p> <p><span class="hlt">Dust</span> reverberation is an important technique for studying the inner structure of AGNs and probing the properties of astrophysical <span class="hlt">dust</span>, and even has some potential as a cosmological probe. We will discuss two recent results that pose a serious limitation to understanding <span class="hlt">dust</span> reverberation at the present time. First, recent high-cadence monitoring of the UV and optical continuum in two AGNs, NGC 2617 and NGC 5548, have yielded unambiguous lags between variations of the UV continuum and corresponding variations of the continuum at longer wavelengths. In the absence of UV data, this <span class="hlt">leads</span> to a systematic underestimate of the innermost radius where <span class="hlt">dust</span> is found. This similarly <span class="hlt">leads</span> to an underestimate of the size of the broad emission-line region, although it does not affect the AGN black hole mass scale, which calibrates out this effect. Second, broad-band monitoring of continuum variations in the optical through near-IR show that the innermost <span class="hlt">dust</span> is not necessarily at the 'instantaneous sublimation radius.' The innermost <span class="hlt">dust</span> can be considerably cooler than expected at the sublimation radius and thus can heat up without sublimating when the central continuum source becomes more luminous (see the poster by Pott).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014prdu.book.....A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014prdu.book.....A"><span>Protoplanetary <span class="hlt">Dust</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Apai, D.´niel; Lauretta, Dante S.</p> <p>2014-02-01</p> <p>Preface; 1. Planet formation and protoplanetary <span class="hlt">dust</span> Daniel Apai and Dante Lauretta; 2. The origins of protoplanetary <span class="hlt">dust</span> 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 <span class="hlt">dust</span> analogs in astrophysical environments John R. Brucato and Joseph A. Nuth III; 6. <span class="hlt">Dust</span> composition in protoplanetaty <span class="hlt">dust</span> Michiel Min and George Flynn; 7. <span class="hlt">Dust</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28600726','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28600726"><span>The influence of physicochemical parameters on bioaccessibility-adjusted hazard quotients for copper, <span class="hlt">lead</span> and zinc in different grain size fractions of urban street <span class="hlt">dusts</span> and soils.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dehghani, Sharareh; Moore, Farid; Vasiluk, Luba; Hale, Beverley A</p> <p>2017-06-09</p> <p>When the hazard quotient for ingestion (HQI) of a trace element in soil and <span class="hlt">dust</span> particles is adjusted for the element's bioaccessibility, the HQI is typically reduced as compared to its calculation using pseudo-total element concentration. However, those studies have mostly used bulk particles (<2 mm or <250 µm), and the reduction in HQI when expressed as bioaccessible metal may not be similar among particle size fractions, the possibility probed by the present study of street <span class="hlt">dusts</span> and soils collected in Tehran. The highest Cu, Pb and Zn near-total concentrations occurred in the finest particles of <span class="hlt">dusts</span> and soils. Bioaccessible concentrations of Cu, Pb and Zn in the particles (mg kg(-1)) were obtained using simple bioaccessibility extraction test (SBET). The bioaccessibility (%) did not vary much among near-total concentrations. In the bulk (<250 µm) sample, the bioaccessible concentration of Cu and Pb increased as the pH of sample increased, while Zn bioaccessibility (%) in the bulk particles was influenced by organic matter and cation exchange capacity. X-ray diffraction identified sulfide and sulfate minerals in all of the size-fractionated particles, which are insoluble to slightly soluble in acidic conditions and included most of the Cu and Pb in the samples. The only Zn-bearing mineral identified was hemimorphite, which would be highly soluble in the SBET conditions. The calculated HQI suggested potential non-carcinogenic health risk to children and adults from ingestions of soils and <span class="hlt">dusts</span> regardless of particle size consideration, in the order of Zn > Pb ≥ Cu. The HQI calculated from near-total metal was not much different for particle size classes relative to bulk particles; however, the bioaccessibility percent-adjusted HQI for Pb was higher for the smaller particles than the bulk. This work is novel in its approach to compare HQI for a bulk sample of particles with its composite particle size fractions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ACP....17.3799A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ACP....17.3799A"><span>Sensitivity of transatlantic <span class="hlt">dust</span> transport to chemical aging and related atmospheric processes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Abdelkader, Mohamed; Metzger, Swen; Steil, Benedikt; Klingmüller, Klaus; Tost, Holger; Pozzer, Andrea; Stenchikov, Georgiy; Barrie, Leonard; Lelieveld, Jos</p> <p>2017-03-01</p> <p>We present a sensitivity study on transatlantic <span class="hlt">dust</span> transport, a process which has many implications for the atmosphere, the ocean and the climate. We investigate the impact of key processes that control the <span class="hlt">dust</span> outflow, i.e., the emission flux, convection schemes and the chemical aging of mineral <span class="hlt">dust</span>, by using the EMAC model following Abdelkader et al. (2015). To characterize the <span class="hlt">dust</span> outflow over the Atlantic Ocean, we distinguish two geographic zones: (i) <span class="hlt">dust</span> interactions within the Intertropical Convergence Zone (ITCZ), or the <span class="hlt">dust</span>-ITCZ interaction zone (DIZ), and (ii) the adjacent <span class="hlt">dust</span> transport over the Atlantic Ocean (DTA) zone. In the latter zone, the <span class="hlt">dust</span> <span class="hlt">loading</span> shows a steep and linear gradient westward over the Atlantic Ocean since particle sedimentation is the dominant removal process, whereas in the DIZ zone aerosol-cloud interactions, wet deposition and scavenging processes determine the extent of the <span class="hlt">dust</span> outflow. Generally, the EMAC simulated <span class="hlt">dust</span> compares well with CALIPSO observations; however, our reference model configuration tends to overestimate the <span class="hlt">dust</span> extinction at a lower elevation and underestimates it at a higher elevation. The aerosol optical depth (AOD) over the Caribbean responds to the <span class="hlt">dust</span> emission flux only when the emitted <span class="hlt">dust</span> mass is significantly increased over the source region in Africa by a factor of 10. These findings point to the dominant role of <span class="hlt">dust</span> removal (especially wet deposition) in transatlantic <span class="hlt">dust</span> transport. Experiments with different convection schemes have indeed revealed that the transatlantic <span class="hlt">dust</span> transport is more sensitive to the convection scheme than to the <span class="hlt">dust</span> emission flux parameterization. To study the impact of <span class="hlt">dust</span> chemical aging, we focus on a major <span class="hlt">dust</span> outflow in July 2009. We use the calcium cation as a proxy for the overall chemical reactive <span class="hlt">dust</span> fraction and consider the uptake of major inorganic acids (i.e., H2SO4, HNO3 and HCl) and their anions, i.e., sulfate (SO42-), bisulfate (HSO4</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017NatGe..10..274K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017NatGe..10..274K"><span>Smaller desert <span class="hlt">dust</span> cooling effect estimated from analysis of <span class="hlt">dust</span> size and abundance</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kok, Jasper F.; Ridley, David A.; Zhou, Qing; Miller, Ron L.; Zhao, Chun; Heald, Colette L.; Ward, Daniel S.; Albani, Samuel; Haustein, Karsten</p> <p>2017-03-01</p> <p>Desert <span class="hlt">dust</span> aerosols affect Earth's global energy balance through direct interactions with radiation, and through indirect interactions with clouds and ecosystems. But the magnitudes of these effects are so uncertain that it remains unclear whether atmospheric <span class="hlt">dust</span> has a net warming or cooling effect on global climate. Consequently, it is still uncertain whether large changes in atmospheric <span class="hlt">dust</span> <span class="hlt">loading</span> over the past century have slowed or accelerated anthropogenic climate change, or what the effects of potential future changes in <span class="hlt">dust</span> <span class="hlt">loading</span> will be. Here we present an analysis of the size and abundance of <span class="hlt">dust</span> aerosols to constrain the direct radiative effect of <span class="hlt">dust</span>. Using observational data on <span class="hlt">dust</span> abundance, in situ measurements of <span class="hlt">dust</span> optical properties and size distribution, and climate and atmospheric chemical transport model simulations of <span class="hlt">dust</span> lifetime, we find that the <span class="hlt">dust</span> found in the atmosphere is substantially coarser than represented in current global climate models. As coarse <span class="hlt">dust</span> warms the climate, the global <span class="hlt">dust</span> direct radiative effect is likely to be less cooling than the ~-0.4 W m-2 estimated by models in a current global aerosol model ensemble. Instead, we constrain the <span class="hlt">dust</span> direct radiative effect to a range between -0.48 and +0.20 W m-2, which includes the possibility that <span class="hlt">dust</span> causes a net warming of the planet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2001/0034/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2001/0034/report.pdf"><span>Concentrations and <span class="hlt">loads</span> of cadmium, zinc, and <span class="hlt">lead</span> in the main stem Coeur d'Alene River, Idaho—March, June, September, and October 1999</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Woods, P.F.</p> <p>2001-01-01</p> <p>of the effects of different river discharges and lake levels of Coeur d'Alene Lake on the transport of cadmium, zinc, and <span class="hlt">lead</span> within the main stem Coeur d'Alene River. In particular, water-quality data and <span class="hlt">loads</span> during a broad range of hydrologic conditions were examined to determine if the river channel, flood plain, and associated ground water along the main stem Coeur d'Alene River acted as sources or sinks of trace elements. Water-quality samples were collected at six riverine stations and one lake station along a 35-mile reach during March, June, September, and October of 1999. Samples were analyzed for whole-water recoverable, filtered (0.45 micrometer), and dissolved (0.01 micrometer) concentrations of cadmium, zinc, and <span class="hlt">lead</span>. Concentrations and <span class="hlt">loads</span> of cadmium and zinc measured during the four sampling trips were predominately in the filtered and dissolved fraction ,rather than particulate. The smallest concentrations were measured during the June sampling trip when flows were high and snowmelt runoff diluted riverine concentrations. Conversely, the largest concentrations were measured during the latter two sampling trips when flows were low because a larger proportion of the river's discharge was contributed by ground-water inflow. During each sampling trip, cadmium and zinc concentrations generally decreased in a downstream directioeven as discharge increased in a downstream direction. Spatial and temporal trends exhibited by <span class="hlt">lead</span> concentrations and <span class="hlt">loads</span> during the four sampling trips were different from those of cadmium and zinc because of the propensity for <span class="hlt">lead</span> to adsorb to sediment particles. Whole-water recoverable <span class="hlt">lead</span> concentrations and <span class="hlt">loads</span> during the four sampling trips were predominantly in the particulate fraction, with filtered and dissolved concentrations and <span class="hlt">loads</span> composing a much smaller proportion of the recoverable fraction compared to cadmium and zinc. Filtered <span class="hlt">lead</span> concentrations generally increased at a faster rate in the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ACPD...1321259M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ACPD...1321259M"><span>Saharan <span class="hlt">dust</span> aerosol over the central Mediterranean Sea: optical columnar measurements vs. aerosol <span class="hlt">load</span>, chemical composition and marker solubility at ground level</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Marconi, M.; Sferlazzo, D. M.; Becagli, S.; Bommarito, C.; Calzolai, G.; Chiari, M.; di Sarra, A.; Ghedini, C.; Gómez-Amo, J. L.; Lucarelli, F.; Meloni, D.; Monteleone, F.; Nava, S.; Pace, G.; Piacentino, S.; Rugi, F.; Severi, M.; Traversi, R.; Udisti, R.</p> <p>2013-08-01</p> <p>This study aims at the determination of the mineral contribution to PM10 in the central Mediterranean Sea on the basis of 7 yr of PM10 chemical composition daily measurements made on the island of Lampedusa (35.5° N, 12.6° E). Aerosol optical depth measurements are carried out in parallel while sampling with a multi-stage impactor, and observations with an optical particle counter were performed in selected periods. Based on daily samples, the total content and soluble fraction of selected metals are used to identify and characterize the <span class="hlt">dust</span> events. The total contribution is determined by PIXE (particle-induced X-ray emission) while the composition of the soluble fraction by ICP-AES (inductively coupled plasma atomic emission spectroscopy) after extraction with HNO3 at pH 1.5. The average PM10 concentration at Lampedusa calculated over the period June 2004-December 2010 is 31.5 μg m-3, with low interannual variability. The annual means are below the EU annual standard for PM10, but 9.9% of the total number of daily data exceed the daily threshold value established by the European Commission for PM (50 μg m-3, European Community, EC/30/1999). The Saharan <span class="hlt">dust</span> contribution to PM10 was derived by calculating the contribution of Al, Si, Fe, Ti, non-sea-salt (nss) Ca, nssNa, and nssK oxides in samples in which PIXE data were available. Cases with crustal content exceeding the 75th percentile of the crustal oxide content distribution were identified as <span class="hlt">dust</span> events. Using this threshold we identify 175 events; 31.6% of them (55 events) present PM10 higher than 50 μg m-3, with <span class="hlt">dust</span> contributing by 33% on average. The annual average crustal contribution to PM10 is 5.42 μg m-3, reaching a value as high as 67.9 μg m-3, 49% of PM10, during an intense Saharan <span class="hlt">dust</span> event. The crustal aerosol amount and contribution to PM10 shows a very small seasonal dependence; conversely, the <span class="hlt">dust</span> columnar burden displays an evident annual cycle, with a strong summer maximum (monthly</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eosweb.larc.nasa.gov/project/misr/gallery/china_dust','SCIGOV-ASDC'); return false;" href="https://eosweb.larc.nasa.gov/project/misr/gallery/china_dust"><span>China <span class="hlt">Dust</span></span></a></p> <p><a target="_blank" href="http://eosweb.larc.nasa.gov/">Atmospheric Science Data Center </a></p> <p></p> <p>2013-04-16</p> <p>... 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 <span class="hlt">dust</span>. Airborne <span class="hlt">dust</span> clouds from the ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22348202','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22348202"><span>Andromeda's <span class="hlt">dust</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>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</p> <p>2014-01-10</p> <p>Spitzer Space Telescope and Herschel Space Observatory imaging of M31 is used, with a physical <span class="hlt">dust</span> model, to construct maps of <span class="hlt">dust</span> surface density, <span class="hlt">dust</span>-to-gas ratio, starlight heating intensity, and polycyclic aromatic hydrocarbon (PAH) abundance, out to R ≈ 25 kpc. The global <span class="hlt">dust</span> mass is M {sub d} = 5.4 × 10{sup 7} M {sub ☉}, the global <span class="hlt">dust</span>/H mass ratio is M {sub d}/M {sub H} = 0.0081, and the global PAH abundance is (q {sub PAH}) = 0.039. The <span class="hlt">dust</span> 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 <span class="hlt">dust</span>/gas ratio varies from M {sub d}/M {sub H} ≈ 0.026 at the center to ∼0.0027 at R ≈ 25 kpc. From the <span class="hlt">dust</span>/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 <span class="hlt">dust</span> 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 <span class="hlt">dust</span> 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 <span class="hlt">dust</span> in the central kiloparsec is similar to the overall value of q {sub PAH} in the disk. The silicate-graphite-PAH <span class="hlt">dust</span> model used here is generally able to reproduce the observed <span class="hlt">dust</span> spectral energy distribution across M31, but overpredicts 500 μm emission at R ≈ 2-6 kpc, suggesting that at R = 2-6 kpc, the <span class="hlt">dust</span> opacity varies more steeply with frequency (with β ≈ 2.3 between 200 and 600 μm) than in the model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/696693','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/696693"><span>Conveyor <span class="hlt">dust</span> control</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Goldbeck, L.</p> <p>1999-11-01</p> <p>In the past, three different approaches have been used to control <span class="hlt">dust</span> arising at conveyor <span class="hlt">load</span> zones. They are: <span class="hlt">Dust</span> Containment consists of those mechanical systems employed to keep material inside the transfer point with the main material body. <span class="hlt">Dust</span> Suppression systems increase the mass of suspended <span class="hlt">dust</span> particles, allowing them to fall from the air stream. <span class="hlt">Dust</span> Collection is the mechanical capture and return of airborne material after it becomes airborne from the main material body. Previously, these three approaches have always been seen as separate entities. They were offered by separate organizations competing in the marketplace. The three technologies vied for their individual piece of the rock, at the expense of the other technologies (and often at the expense of overall success). There have been considerable amounts of I`m better selling, as well as finger pointing at the other systems when problems arose. Each system claimed its own technology was the best, providing the most effective, most cost-efficient, most maintenance-free solution to fugitive material.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ilgp.confE...3V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ilgp.confE...3V"><span>Differential <span class="hlt">dust</span> attenuation in CALIFA galaxies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vale Asari, N.; Cid Fernandes, R.; Amorim, A. L.; Lacerda, E. A. D.; Schlickmann, M.; Wild, V.; Kennicutt, R. C.</p> <p>2016-06-01</p> <p><span class="hlt">Dust</span> attenuation has long been treated as a simple parameter in SED fitting. Real galaxies are, however, much more complicated: The measured <span class="hlt">dust</span> attenuation is not a simple function of the <span class="hlt">dust</span> optical depth, but depends strongly on galaxy inclination and the relative distribution of stars and <span class="hlt">dust</span>. We study the nebular and stellar <span class="hlt">dust</span> attenuation in CALIFA galaxies, and propose some empirical recipes to make the <span class="hlt">dust</span> treatment more realistic in spectral synthesis codes. By adding optical recombination emission lines, we find better constraints for differential attenuation. Those recipes can be applied to unresolved galaxy spectra, and <span class="hlt">lead</span> to better recovered star formation rates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20070010753','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20070010753"><span>Lunar <span class="hlt">Dust</span> Characterization for Exploration Life Support Systems</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Agui, Juan H.</p> <p>2007-01-01</p> <p>Lunar <span class="hlt">dust</span> effects can have a significant impact on the performance and maintenance of future exploration life support systems. Filtration systems will be challenged by the additional <span class="hlt">loading</span> from lunar <span class="hlt">dust</span>, and mitigation technology and strategies have to be adapted to protect sensitive equipment. An initial characterization of lunar <span class="hlt">dust</span> and simulants was undertaken. The data emphasize the irregular morphology of the <span class="hlt">dust</span> particles and the frequency dependence of lunar <span class="hlt">dust</span> layer detachment from shaken surfaces.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19481686','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19481686"><span>Alteration of the diffusional barrier property of the nail <span class="hlt">leads</span> to greater terbinafine drug <span class="hlt">loading</span> and permeation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nair, Anroop B; Sammeta, Srinivasa M; Kim, Hyun D; Chakraborty, Bireswar; Friden, Phillip M; Murthy, S Narasimha</p> <p>2009-06-22</p> <p>The diffusional barrier property of biological systems varies with ultrastructural organization of the tissues and/or cells, and often plays an important role in drug delivery. The nail plate is a thick, hard and impermeable membrane which makes topical nail drug delivery challenging. The current study investigated the effect of physical and chemical alteration of the nail on the trans-ungual drug delivery of terbinafine hydrochloride (TH) under both passive and iontophoretic conditions. Physical alterations were carried out by dorsal or ventral nail layer abrasion, while chemical alterations were performed by defatting or keratolysis or ionto-keratolysis of the nails. Terbinafine permeation into and across the nail plate following various nail treatments showed similar trends in both passive and iontophoretic delivery, although the extent of drug delivery varied with treatment. Application of iontophoresis to the abraded nails significantly improved (P<0.05) TH permeation and <span class="hlt">loading</span> compared to abraded nails without iontophoresis or normal nails with iontophoresis. Drug permeation was not enhanced when the nail plate was defatted. Keratolysis moderately enhanced the permeation but not the drug <span class="hlt">load</span>. Ionto-keratolysis enhanced TH permeation and drug <span class="hlt">load</span> significantly (P<0.05) during passive and iontophoretic delivery as compared to untreated nails. Ionto-keratolysis may be more efficient in permeabilization of nail plates than long term exposure to keratolysing agents.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/20020661','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/20020661"><span>An evaluation of the effectiveness of <span class="hlt">lead</span> paint hazard reduction when conducted by homeowners and landlords</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Etre, L.A.; Reynolds, S.J.; Burmeister, L.F.; Whitten, P.S.; Gergely, R.</p> <p>1999-08-01</p> <p>This research project was conducted in collaboration with the Iowa Department of Public Health to evaluate whether property owners who follow recommended procedures for <span class="hlt">lead</span>-based paint removal/repair can do the work safely and effectively. This study included 29 homes where a <span class="hlt">lead</span>-based paint hazard had been identified and <span class="hlt">lead</span>-based paint was removed or repaired (hazard reduction). Exposure evaluation included pre-project surface <span class="hlt">dust</span> wipe sampling, air monitoring during <span class="hlt">lead</span>-based paint removal, post-project surface <span class="hlt">dust</span> wipe sampling, and pre- and post-project blood samples from adult study participants. The comparison of surface <span class="hlt">dust</span> wipe samples taken before and after <span class="hlt">lead</span> paint hazard reduction was used to evaluate the effectiveness of <span class="hlt">lead</span> paint hazard reduction. The <span class="hlt">lead</span> <span class="hlt">loadings</span> on window sill surfaces in the work area were significantly lower after completion of the project, and the <span class="hlt">lead</span>-based paint removal did not contaminate the adjoining living area. The proportion of homes with surface <span class="hlt">dust</span> <span class="hlt">lead</span> <span class="hlt">loading</span> exceeding Department of Housing and Urban Development (HUD) clearance standard was 73% pre-project and 38% post-project. Personal airborne exposures during <span class="hlt">lead</span> removal activities reinforce the need to respiratory protection and good hygiene. There was no difference in adult pre-/post-blood levels, indicating that participants die remove <span class="hlt">lead</span> in a safe manner with respect to their own exposures. The results indicate that hazard reduction can be done effectively when recommended procedures for the removal of <span class="hlt">lead</span>-based paint are followed.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20830913','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20830913"><span>Laboratory system for <span class="hlt">dust</span> generation from soils.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Domingo, Rebecca A; Southard, Randal J; Lee, Kiyoung</p> <p>2010-01-01</p> <p>Farm workers and residential communities adjacent to agricultural fields can be exposed to soil <span class="hlt">dust</span> generated during field operations at levels that could result in respiratory problems. However, field sampling of agricultural <span class="hlt">dust</span> faces logistical problems from spatial and temporal differences in soil properties, field operations, and meteorological conditions. To minimize these problems, we designed a <span class="hlt">dust</span> generator that simulates <span class="hlt">dust</span> generation during tilling of agricultural fields to provide samples of particulate matter derived from bulk soil and developed optimal operating conditions to assure reproducible results. The <span class="hlt">dust</span> generator consisted of a rotating chamber, where soil samples were <span class="hlt">loaded</span> and tumbled, and a settling chamber, where airborne soil <span class="hlt">dust</span> samples were collected using particle size-selective samplers. The following operating conditions for <span class="hlt">dust</span> generation were evaluated: initial soil mass, air intake, rotation speed, and sampling time to optimize <span class="hlt">dust</span> sampling. We compared the laboratory-generated <span class="hlt">dust</span> from soil samples with field <span class="hlt">dust</span> that we collected from the same plots during agricultural operations. We determined from X-ray diffraction and energy-dispersive X-ray analyses that the mineralogy and chemical composition of field- and laboratory-generated <span class="hlt">dust</span> were similar, indicating that the apparatus reasonably simulated field mechanical processes that produce airborne particulate matter from soils. The results suggest that the laboratory <span class="hlt">dust</span> generator provides reliable samples of soil-derived <span class="hlt">dust</span> and could be useful for future studies involving airborne particulate material from soils.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://kidshealth.org/en/parents/lead-poisoning.html','NIH-MEDLINEPLUS'); return false;" href="http://kidshealth.org/en/parents/lead-poisoning.html"><span><span class="hlt">Lead</span> Poisoning (For Parents)</span></a></p> <p><a target="_blank" href="http://medlineplus.gov/">MedlinePlus</a></p> <p></p> <p></p> <p>... metal used in everything from construction materials to batteries, can cause serious health problems, particularly in young ... introduce <span class="hlt">lead</span> <span class="hlt">dust</span> into the home. water that flows through old <span class="hlt">lead</span> pipes or faucets, if the ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22982806','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22982806"><span>The physics of wind-blown sand and <span class="hlt">dust</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kok, Jasper F; Parteli, Eric J R; Michaels, Timothy I; Karam, Diana Bou</p> <p>2012-10-01</p> <p>The transport of sand and <span class="hlt">dust</span> by wind is a potent erosional force, creates sand dunes and ripples, and <span class="hlt">loads</span> the atmosphere with suspended <span class="hlt">dust</span> aerosols. This paper presents an extensive review of the physics of wind-blown sand and <span class="hlt">dust</span> on Earth and Mars. Specifically, we review the physics of aeolian saltation, the formation and development of sand dunes and ripples, the physics of <span class="hlt">dust</span> aerosol emission, the weather phenomena that trigger <span class="hlt">dust</span> storms, and the lifting of <span class="hlt">dust</span> by <span class="hlt">dust</span> devils and other small-scale vortices. We also discuss the physics of wind-blown sand and dune formation on Venus and Titan.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMSM11C1769S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMSM11C1769S"><span>Planetary Magnetosphere Probed by Charged <span class="hlt">Dust</span> Particles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sternovsky, Z.; Horanyi, M.; Gruen, E.; Srama, R.; Auer, S.; Kempf, S.; Krueger, H.</p> <p>2010-12-01</p> <p>In-situ and remote sensing observations combined with theoretical and numerical modeling greatly advanced our understanding planetary magnetospheres. <span class="hlt">Dust</span> is an integral component of the Saturnian and Jovian magnetospheres where it can act as a source/sink of plasma particles (<span class="hlt">dust</span> 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 <span class="hlt">lead</span> to unusual <span class="hlt">dust</span> dynamics, including the transport, capture, and ejection of <span class="hlt">dust</span> grains. The study of the temporal and spatial evolution of fine <span class="hlt">dust</span> within or outside the magnetosphere thus provides a unique way to combine data from a large number of observations: plasma, plasma wave, <span class="hlt">dust</span>, and magnetic field measurements. The <span class="hlt">dust</span> detectors on board the Galileo and Cassini spacecrafts <span class="hlt">lead</span> to major discoveries, including the jovian <span class="hlt">dust</span> stream originating from Io or the in-situ sampling and analysis of the plumes of Enceladus. Recent advancement in <span class="hlt">dust</span> detector technology enables accurate measurement of the <span class="hlt">dust</span> trajectory and elemental composition that can greatly enhance the understanding of <span class="hlt">dust</span> magnetorspheric interaction and indentify the source of the <span class="hlt">dust</span> with high precision. The capabilities of a modern <span class="hlt">dust</span> detector thus can provide support for the upcoming Europa Jupiter System Mission.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21246372','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21246372"><span>Moderate <span class="hlt">loading</span> of the human osteoarthritic knee joint <span class="hlt">leads</span> to lowering of intraarticular cartilage oligomeric matrix protein.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Helmark, Ida C; Petersen, Marie C H; Christensen, Helle E; Kjaer, Michael; Langberg, Henning</p> <p>2012-04-01</p> <p>The non-pharmacological treatment of osteoarthritis (OA) includes exercise therapy; however, little is known about the specific effect of exercise on the joint per se. The purpose of the present study was to investigate the direct effects of a <span class="hlt">load</span>-bearing exercise upon cartilage in a single, human osteoarthritic joint determined by biochemical markers of cartilage turnover and inflammation in the synovial fluid (SF), serum and urine. Eleven subjects with OA of the knee(s), but with no other joint- or inflammatory disorders, volunteered for the study and had samples of blood, urine and synovial fluid drawn both at baseline and following 30-min one-legged knee-extension exercise. Workload: 60% of 1 RM (Repetition Maximum). Determination of cartilage oligomeric matrix protein (COMP), aggrecan, C-terminal collagen II peptide (CTX-II) and interleukin (IL)-6 were performed in synovial fluid (SF), serum and urine. A significant decrease was found in SF concentration of COMP following exercise, whereas aggrecan, CTX-II and IL-6 remained unchanged. No differences in any of the tested markers were found in serum and urine between baseline and post-exercise. Thirty minutes of mechanical <span class="hlt">loading</span> of a single knee joint in human subjects with knee OA resulted in a reduced COMP concentration in SF.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28597504','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28597504"><span>Gold(Core)-<span class="hlt">Lead</span>(Shell) Nanoparticle-<span class="hlt">Loaded</span> Titanium(IV) Oxide Prepared by Underpotential Photodeposition: Plasmonic Water Oxidation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Negishi, Ryo; Naya, Shin-Ichi; Kobayashi, Hisayoshi; Tada, Hiroaki</p> <p>2017-08-21</p> <p>Underpotential photodeposition of Pb yields an ultrathin shell layer on the Au(111) surface of Au nanoparticle(NP)-<span class="hlt">loaded</span> TiO2 (Au/TiO2 ) with heteroepitaxial nanojunctions. The localized surface plasmon resonance of Au/TiO2 undergoes no damping with the Pb-shell formation, and the Pb shell offers resistance to aerobic oxidation. Mesoporous films comprising the Au(core)-Pb(shell) NP-<span class="hlt">loaded</span> TiO2 and unmodified Au/TiO2 were formed on fluorine-doped tin oxide (FTO) electrode. Using them as the photoanode, photoelectrochemical cells were fabricated, and the photocurrent was measured under illumination of simulated sunlight. The photocurrent for water splitting is dramatically enhanced by the Pb-shell formation. The photoelectrochemical measurements of the hot-electron lifetime and density functional theory calculations for model clusters indicate that the Pb-shell effect originates from the charge separation enhancement. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001PhDT.......166K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001PhDT.......166K"><span>Exozodiacal <span class="hlt">dust</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kuchner, Marc Jason</p> <p></p> <p>Besides the sun, the most luminous feature of the solar system is a cloud of "zodiacal" <span class="hlt">dust</span> released by asteroids and comets that pervades the region interior to the asteroid belt. Similar clouds of <span class="hlt">dust</span> 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 <span class="hlt">dust</span>: (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 <span class="hlt">dust</span> in our own system based on COBE DIRBE observations and place upper limits on the density of exozodiacal <span class="hlt">dust</span> 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 <span class="hlt">dust</span> 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 <span class="hlt">dust</span> 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 <span class="hlt">dust</span> complex: (1) We searched the COBE DIRBE Sky and Zodi Atlas for a wake of <span class="hlt">dust</span> 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 <span class="hlt">dust</span> near</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24995641','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24995641"><span>Size-resolved <span class="hlt">dust</span> and aerosol contaminants associated with copper and <span class="hlt">lead</span> smelting emissions: implications for emission management and human health.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Csavina, Janae; Taylor, Mark P; Félix, Omar; Rine, Kyle P; Eduardo Sáez, A; Betterton, Eric A</p> <p>2014-09-15</p> <p>Mining operations, including crushing, grinding, smelting, refining, and tailings management, are a significant source of airborne metal and metalloid contaminants such as As, Pb and other potentially toxic elements. In this work, we show that size-resolved concentrations of As and Pb generally follow a bimodal distribution with the majority of contaminants in the fine size fraction (<1 μm) around mining activities that include smelting operations at various sites in Australia and Arizona. This evidence suggests that contaminated fine particles (<1 μm) are the result of vapor condensation and coagulation from smelting operations while coarse particles are most likely the result of windblown <span class="hlt">dust</span> from contaminated mine tailings and fugitive emissions from crushing and grinding activities. These results on the size distribution of contaminants around mining operations are reported to demonstrate the ubiquitous nature of this phenomenon so that more effective emission management and practices that minimize health risks associated with metal extraction and processing can be developed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1510653R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1510653R"><span><span class="hlt">Dust</span> Assimilation in a Martian Global Climate Model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ruan, Tao; Montabone, Luca; Read, Peter; Lewis, Stephen</p> <p>2013-04-01</p> <p> able to represent many aspects of the evolution of atmospheric structure and <span class="hlt">dust</span> <span class="hlt">loading</span> in the atmosphere, including the altitude of the top of the <span class="hlt">dust</span> layer at different seasons and latitudes as observed on Mars. However, a lack of measurements of <span class="hlt">dust</span> profiles in the lower atmosphere may <span class="hlt">lead</span> to an under-constrained <span class="hlt">dust</span> simulation near the surface. These kinds of study may point to ways of improving numerical modeling and guide the new implementation of measurements that might help the further understanding of the Martian atmospheric circulation and climate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4837371','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4837371"><span>Substantial <span class="hlt">dust</span> loss of bioavailable phosphorus from agricultural soils</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Katra, Itzhak; Gross, Avner; Swet, Nitzan; Tanner, Smadar; Krasnov, Helena; Angert, Alon</p> <p>2016-01-01</p> <p>Phosphorus (P) is an essential element in terrestrial ecosystems. Knowledge on the role of <span class="hlt">dust</span> in the biogeochemical cycling of phosphorus is very limited with no quantitative information on aeolian (by wind) P fluxes from soils. The aim of this study is to focus on P cycling via <span class="hlt">dust</span> emissions under common land-use practices in an arid environment by integration of sample analyses and aeolian experiments. The experiments indicate significant P fluxes by PM10 <span class="hlt">dust</span> due to agricultural land use. Even in a single wind-<span class="hlt">dust</span> event at moderate velocity (7.0 m s−1), P flux in conventional agricultural fields can reach 1.83 kg km−2, that accumulates to a considerable amount per year at a regional scale. The results highlight a negative yearly balance in P content (up to hundreds kg km−2) in all agricultural soils, and thus more P nutrition is required to maintain efficient yield production. In grazing areas where no P nutrition is applied, the soil degradation process can <span class="hlt">lead</span> to desertification. Emission of P from soil <span class="hlt">dust</span> sources has significant implications for soil nutrient resources and management strategies in agricultural regions as well as for <span class="hlt">loading</span> to the atmosphere and global biogeochemical cycles. PMID:27095629</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatSR...624736K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatSR...624736K"><span>Substantial <span class="hlt">dust</span> loss of bioavailable phosphorus from agricultural soils</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Katra, Itzhak; Gross, Avner; Swet, Nitzan; Tanner, Smadar; Krasnov, Helena; Angert, Alon</p> <p>2016-04-01</p> <p>Phosphorus (P) is an essential element in terrestrial ecosystems. Knowledge on the role of <span class="hlt">dust</span> in the biogeochemical cycling of phosphorus is very limited with no quantitative information on aeolian (by wind) P fluxes from soils. The aim of this study is to focus on P cycling via <span class="hlt">dust</span> emissions under common land-use practices in an arid environment by integration of sample analyses and aeolian experiments. The experiments indicate significant P fluxes by PM10 <span class="hlt">dust</span> due to agricultural land use. Even in a single wind-<span class="hlt">dust</span> event at moderate velocity (7.0 m s‑1), P flux in conventional agricultural fields can reach 1.83 kg km‑2, that accumulates to a considerable amount per year at a regional scale. The results highlight a negative yearly balance in P content (up to hundreds kg km‑2) in all agricultural soils, and thus more P nutrition is required to maintain efficient yield production. In grazing areas where no P nutrition is applied, the soil degradation process can <span class="hlt">lead</span> to desertification. Emission of P from soil <span class="hlt">dust</span> sources has significant implications for soil nutrient resources and management strategies in agricultural regions as well as for <span class="hlt">loading</span> to the atmosphere and global biogeochemical cycles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-GSFC_20170927_Archive_e001324.jpg.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-GSFC_20170927_Archive_e001324.jpg.html"><span><span class="hlt">Dust</span> storm in Alaska</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2017-09-27</p> <p><span class="hlt">Dust</span> storm in Alaska captured by Aqua/MODIS on Nov. 17, 2013 at 21:45 UTC. When glaciers grind against underlying bedrock, they produce a silty powder with grains finer than sand. Geologists call it “glacial flour” or “rock flour.” This iron- and feldspar-rich substance often finds its ways into rivers and lakes, coloring the water brown, grey, or aqua. When river or lake levels are low, the flour accumulates on drying riverbanks and deltas, leaving raw material for winds to lift into the air and create plumes of <span class="hlt">dust</span>. Scientists are monitoring Arctic <span class="hlt">dust</span> for a number of reasons. <span class="hlt">Dust</span> storms can reduce visibility enough to disrupt air travel, and they can pose health hazards to people on the ground. <span class="hlt">Dust</span> is also a key source of iron for phytoplankton in regional waters. Finally, there is the possibility that <span class="hlt">dust</span> events are becoming more frequent and severe due to ongoing recession of glaciers in coastal Alaska. To read more about <span class="hlt">dust</span> storm in this region go to: earthobservatory.nasa.gov/IOTD/view.php?id=79518 Credit: NASA/GSFC/Jeff Schmaltz/MODIS Land Rapid Response Team NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a <span class="hlt">leading</span> role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1020959','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1020959"><span>Replacement of <span class="hlt">lead-loaded</span> glovebox glove with attenuation medium that are not RCRA-hazardous metals</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cournoyer, Michael E; George, Gerald L; Dodge, Robert L; Chunglo, Steve</p> <p>2010-01-01</p> <p>Programmatic operations at the Los Alamos National Laboratory Plutonium Facility (TA-55) involve working with various amounts of plutonium and other highly toxic, alpha-emitting materials. The spread of radiological contamination on surfaces, airborne contamination, and excursions of contaminants into the operator's breathing zone are prevented through the use of a variety of gloveboxes (the glovebox, coupled with an adequate negative pressure gradient, provides primary confinement). Radiation shielding is commonly used to protect the glovebox worker from unintentional direct and secondary radiation exposure, while working with plutonium-238 and plutonium-239. In these environments, low-energy photons, i.e., those less than 250 keY, are encountered. Shielding glove box gloves are traditionally composed of <span class="hlt">lead</span>-based materials, but these are now considered hazardous waste. This has prompted the development of new, nonhazardous- shielding gJovebox gloves. No studies, however, have investigated the effectiveness of these new glovebox gloves. We examined both <span class="hlt">leaded</span> and nonhazardous- shielding glovebox gloves and compared their attenuation effectiveness over the energy range of interest at TA-55. All measurements are referenced to <span class="hlt">lead</span> sheets, allowing direct comparisons to the common industry standard of 0.1 mm <span class="hlt">lead</span> equivalent material. The attenuation properties of both types of glovebox gloves vary with energy, making it difficult for manufacturers to claim <span class="hlt">lead</span> equivalency across the entire energy range used at TA-55. The positions of materials' photon energy absorption edges, which are particularly important to improved attenuation performance, depending upon the choice of radiation energy range, are discussed. This effort contributes to the Los Alamos National Laboratory Continuous Improvement Program by improving the efficiency, cost effectiveness, and formality of glovebox operations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18440884','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18440884"><span>Catalyst-dependent drug <span class="hlt">loading</span> of LDI-glycerol polyurethane foams <span class="hlt">leads</span> to differing controlled release profiles.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sivak, Wesley N; Pollack, Ian F; Petoud, Stéphane; Zamboni, William C; Zhang, Jianying; Beckman, Eric J</p> <p>2008-09-01</p> <p>The purpose of the present study was to develop biodegradable and biocompatible polyurethane foams based on lysine diisocyanate (LDI) and glycerol to be used as drug-delivery systems for the controlled release of 7-tert-butyldimethylsilyl-10-hydroxy-camptothecin (DB-67). The impact of urethane catalysts on cellular proliferation was assessed in an attempt to enhance the biocompatibility of our polyurethane materials. DB-67, a potent camptothecin analog, was then incorporated into LDI-glycerol polyurethane foams with two different amine urethane catalysts: 1,4-diazobicyclo[2.2.2]-octane (DABCO) and 4,4'-(oxydi-2,1-ethane-diyl)bismorpholine (DMDEE). The material morphologies of the polyurethane foams were analyzed via scanning electron microscopy, and DB-67 distribution was assessed by way of fluorescence microscopy. Both foam morphology and drug distribution were found to correlate to the amine catalyst used. Hydrolytic release rates of DB-67 from the polyurethane foams were catalyst dependent and also demonstrated greater drug <span class="hlt">loads</span> being released at higher temperatures. The foams were capable of delivering therapeutic concentrations of DB-67 in vitro over an 11week test period. Cellular proliferation assays demonstrate that empty LDI-glycerol foams did not significantly alter the growth of malignant human glioma cell lines (P<0.05). DB-67 <span class="hlt">loaded</span> LDI-glycerol polyurethane foams were found to inhibit cellular proliferation by at least 75% in all the malignant glioma cell lines tested (P<1.0x10(-8)). These results clearly demonstrate the long-term, catalyst-dependent release of DB-67 from LDI-glycerol polyurethane foams, indicating their potential for use in implantable drug-delivery devices.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4035666','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4035666"><span>Evaluation of HEPA vacuum cleaning and dry steam cleaning in reducing levels of polycyclic aromatic hydrocarbons and house <span class="hlt">dust</span> mite allergens in carpets</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Yu, Chang Ho; Yiin, Lih-Ming; Fan, Zhi-Hua (Tina); Rhoads, George G.</p> <p>2014-01-01</p> <p>Dry steam cleaning, which has gained recent attention as an effective method to reduce house <span class="hlt">dust</span> mite (HDM) allergen concentration and <span class="hlt">loading</span> in carpets, was evaluated in this study for its efficacy in lowering levels of polycyclic aromatic hydrocarbons (PAHs) as well as HDM allergens. Fifty urban homes with wail-to-wall carpets, mostly low-income and with known <span class="hlt">lead</span> contamination, were studied in 2003 and 2004. Two carpet-cleaning interventions were compared: Repeated HEPA (High Efficiency Particulate Air filtered) vacuuming alone and repeated HEPA vacuuming supplemented with dry steam cleaning. Vacuum samples were collected to measure carpet <span class="hlt">loading</span> of <span class="hlt">dust</span> and contaminants immediately before and after cleaning. Paired comparisons were conducted to evaluate the effectiveness of the cleaning protocols in reducing the levels of PAHs and HDM allergens in carpets. The results indicated that both cleaning methods substantially reduced the <span class="hlt">loading</span> of PAHs and HDM allergens as well as <span class="hlt">dust</span> in carpets (p < 0.0001). The reductions in <span class="hlt">loading</span> of <span class="hlt">dust</span> (64.4%), PAHs (69.1%), and HDM allergens (85.5%), by dry steam cleaning plus repetitive HEPA vacuuming were larger than the reductions by regular HEPA vacuuming alone: <span class="hlt">dust</span> (55.5%), PAHs (58.6%), and HDM allergens (80.8%), although the difference was statistically significant only for <span class="hlt">dust</span> and PAHs. We conclude that intensive HEPA vacuum cleaning substantially reduced the <span class="hlt">loading</span> of PAHs and HDM allergens in carpets in these urban homes and that dry steam cleaning added modestly to cleaning effectiveness. PMID:19137159</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24603870','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24603870"><span>In vivo administration of a JAK3 inhibitor during acute SIV infection <span class="hlt">leads</span> to significant increases in viral <span class="hlt">load</span> during chronic infection.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Takahashi, Yoshiaki; Byrareddy, Siddappa N; Albrecht, Christina; Brameier, Markus; Walter, Lutz; Mayne, Ann E; Dunbar, Paul; Russo, Robert; Little, Dawn M; Villinger, Tara; Khowawisetsut, Ladawan; Pattanapanyasat, Kovit; Villinger, Francois; Ansari, Aftab A</p> <p>2014-03-01</p> <p>The studies reported herein are the first to document the effect of the in vivo administration of a JAK3 inhibitor for defining the potential role of NK cells during acute SIV infection of a group of 15 rhesus macaques (RM). An additional group of 16 MHC/KIR typed RM was included as controls. The previously optimized in vivo dose regimen (20 mg/kg daily for 35 days) led to a marked depletion of each of the major NK cell subsets both in the blood and gastro-intestinal tissues (GIT) during acute infection. While such depletion had no detectable effects on plasma viral <span class="hlt">loads</span> during acute infection, there was a significant sustained increase in plasma viral <span class="hlt">loads</span> during chronic infection. While the potential mechanisms that <span class="hlt">lead</span> to such increased plasma viral <span class="hlt">loads</span> during chronic infection remain unclear, several correlates were documented. Thus, during acute infection, the administration of the JAK3 inhibitor besides depleting all NK cell subsets also decreased some CD8⁺ T cells and inhibited the mobilization of the plasmacytoid dendritic cells in the blood and their localization to the GIT. Of interest is the finding that the administration of the JAK3 inhibitor during acute infection also resulted in the sustained maintenance during chronic infection of a high number of naïve and central memory CD4⁺ T cells, increases in B cells in the blood, but decreases in the frequencies and function of NKG2a⁺ NK cells within the GIT and blood, respectively. These data identify a unique role for JAK3 inhibitor sensitive cells, that includes NK cells during acute infection that in concert <span class="hlt">lead</span> to high viral <span class="hlt">loads</span> in SIV infected RM during chronic infection without affecting detectable changes in antiviral humoral/cellular responses. Identifying the precise mechanisms by which JAK3 sensitive cells exert their influence is critical with important implications for vaccine design against lentiviruses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/AD1036923','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/AD1036923"><span>Evaluating the Efficiency of Air Shower in Removing <span class="hlt">Lead</span> from Army Combat Uniform Swatches <span class="hlt">Loaded</span> with Gunshot Residue</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2016-03-25</p> <p>and its components with soap and water and dried it with paper towels . The investigators then re-assembled the test assembly, attached the chamber...solution (Hygenall Corp., Huntsville, AL) and dried with paper towels . The investigators then re-assembled the chamber with a blank swatch, attached the...academia. Several articles and white papers have been published on this subject <span class="hlt">leading</span> to “Great Air Shower Debate” session during the CLEANROOMS’95</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.B21I..01P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.B21I..01P"><span>Hydrological and ecological implications of radiative forcing by <span class="hlt">dust</span> in snow</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Painter, T.; Bryant, A. C.; Deems, J. S.; Skiles, M.</p> <p>2012-12-01</p> <p>The runoff from the Colorado River supplies water to over 30 million people in seven US states and Mexico. Climate change projections suggest that this runoff will decrease in the next 50 years by 7-20% due to increases in evapotranspiration and decreases in the ratio of snowfall to rain. Such scenarios challenge the sustainability of the freshwater supply to the southwest US. Recent research however has shown that radiative forcing by <span class="hlt">dust</span> in snow has been shortening snow cover duration by several weeks due to a 5-7-fold increase in <span class="hlt">dust</span> <span class="hlt">loading</span> relative to prior to the European-settlement of the western US in the mid-1800s. In the mountains of the Upper Colorado River, the absolute <span class="hlt">dust</span> radiative forcing across the period ranges from 30 to 75 W m-2, in turn shortening snow cover duration by 21 to 51 days. Extended to the scale of the Upper Colorado River Basin, this impact has brought peak normalized runoff at Lee's Ferry, AZ (Lake Powell) more than three weeks earlier and reduced the total annual runoff by an average of ~5%. In this region, earlier snowmelt forced by <span class="hlt">dust</span> radiative forcing impacts alpine vegetation by increasing synchronicity in phenology across the alpine landscape with increasingly earlier snowmelt. Whereas reduced <span class="hlt">dust</span> <span class="hlt">load</span> results in topographically-sensitive melt and loss of snow cover, the more spatially-uniform snowmelt from <span class="hlt">dust</span> radiative forcing <span class="hlt">leads</span> to synchronized growth and flowering across the landscape. Water managers in the Upper Colorado basin now seek detailed real-time knowledge of <span class="hlt">dust</span> presence, radiative forcing, and its potential to accelerate snowmelt, as well as understanding its implications for water supply under current conditions and in a changed climate. Likewise, water stakeholder groups, water conservation districts, and state and federal agencies are discussing efforts to restabilize soil surfaces in the <span class="hlt">dust</span>-emitting regions to mitigate impacts of <span class="hlt">dust</span> on snowmelt and runoff. However, as these policy</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SSRv..203..143R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SSRv..203..143R"><span><span class="hlt">Dust</span> Devil Tracks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reiss, Dennis; Fenton, Lori; Neakrase, Lynn; Zimmerman, Michael; Statella, Thiago; Whelley, Patrick; Rossi, Angelo Pio; Balme, Matthew</p> <p>2016-11-01</p> <p><span class="hlt">Dust</span> devils that leave dark- or light-toned tracks are common on Mars and they can also be found on the Earth's surface. <span class="hlt">Dust</span> devil tracks (hereinafter DDTs) are ephemeral surface features with mostly sub-annual lifetimes. Regarding their size, DDT widths can range between ˜1 m and ˜1 km, depending on the diameter of <span class="hlt">dust</span> devil that created the track, and DDT lengths range from a few tens of meters to several kilometers, limited by the duration and horizontal ground speed of <span class="hlt">dust</span> devils. DDTs can be classified into three main types based on their morphology and albedo in contrast to their surroundings; all are found on both planets: (a) dark continuous DDTs, (b) dark cycloidal DDTs, and (c) bright DDTs. Dark continuous DDTs are the most common type on Mars. They are characterized by their relatively homogenous and continuous low albedo surface tracks. Based on terrestrial and martian in situ studies, these DDTs most likely form when surficial <span class="hlt">dust</span> layers are removed to expose larger-grained substrate material (coarse sands of ≥500 μm in diameter). The exposure of larger-grained materials changes the photometric properties of the surface; hence <span class="hlt">leading</span> to lower albedo tracks because grain size is photometrically inversely proportional to the surface reflectance. However, although not observed so far, compositional differences (i.e., color differences) might also <span class="hlt">lead</span> to albedo contrasts when <span class="hlt">dust</span> is removed to expose substrate materials with mineralogical differences. For dark continuous DDTs, albedo drop measurements are around 2.5 % in the wavelength range of 550-850 nm on Mars and around 0.5 % in the wavelength range from 300-1100 nm on Earth. The removal of an equivalent layer thickness around 1 μm is sufficient for the formation of visible dark continuous DDTs on Mars and Earth. The next type of DDTs, dark cycloidal DDTs, are characterized by their low albedo pattern of overlapping scallops. Terrestrial in situ studies imply that they are formed when sand</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19750016600','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19750016600"><span>Prediction of unsteady aerodynamic <span class="hlt">loadings</span> caused by <span class="hlt">leading</span> edge and trailing edge control surface motions in subsonic compressible flow: Computer program description</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Redman, M. C.; Rowe, W. S.</p> <p>1975-01-01</p> <p>A digital computer program has been developed to calculate unsteady <span class="hlt">loadings</span> caused by motions of lifting surfaces with <span class="hlt">leading</span> edge or trailing edge controls based on the subsonic kernel function approach. The pressure singularities at hinge line and side edges have been extracted analytically as a preliminary step to solving the integral equation by collocation. The program calculates generalized aerodynamic forces for user supplied deflection modes. Optional intermediate output includes pressure at an array of points, and sectional generalized forces. From one to six controls on the half span can be accommodated.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.8274T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.8274T"><span>Evaluation of atmospheric <span class="hlt">dust</span> prediction models using ground-based observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Terradellas, Enric; María Baldasano, José; Cuevas, Emilio; Basart, Sara; Huneeus, Nicolás; Camino, Carlos; Dundar, Cinhan; Benincasa, Francesco</p> <p>2013-04-01</p> <p>An important step in numerical prediction of mineral <span class="hlt">dust</span> is the model evaluation aimed to assess its performance to forecast the atmospheric <span class="hlt">dust</span> content and to <span class="hlt">lead</span> to new directions in model development and improvement. The first problem to address the evaluation is the scarcity of ground-based routine observations intended for <span class="hlt">dust</span> monitoring. An alternative option would be the use of satellite products. They have the advantage of a large spatial coverage and a regular availability. However, they do have numerous drawbacks that make the quantitative retrievals of aerosol-related variables difficult and imprecise. This work presents the use of different ground-based observing systems for the evaluation of <span class="hlt">dust</span> models in the Regional Center for Northern Africa, Middle East and Europe of the World Meteorological Organization (WMO) Sand and <span class="hlt">Dust</span> Storm Warning Advisory and Assessment System (SDS-WAS). The <span class="hlt">dust</span> optical depth at 550 nm forecast by different models is regularly compared with the AERONET measurements of Aerosol Optical Depth (AOD) for 40 selected stations. Photometric measurements are a powerful tool for remote sensing of the atmosphere allowing retrieval of aerosol properties, such as AOD. This variable integrates the contribution of different aerosol types, but may be complemented with spectral information that enables hypotheses about the nature of the particles. Comparison is restricted to cases with low Ångström exponent values in order to ensure that coarse mineral <span class="hlt">dust</span> is the dominant aerosol type. Additionally to column <span class="hlt">dust</span> <span class="hlt">load</span>, it is important to evaluate <span class="hlt">dust</span> surface concentration and <span class="hlt">dust</span> vertical profiles. Air quality monitoring stations are the main source of data for the evaluation of surface concentration. However they are concentrated in populated and industrialized areas around the Mediterranean. In the present contribution, results of different models are compared with observations of PM10 from the Turkish air quality network for</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015IAUGA..2257933J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015IAUGA..2257933J"><span>Circumstellar <span class="hlt">dust</span> in symbiotic novae</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jurkic, Tomislav; Kotnik-Karuza, Dubravka</p> <p>2015-08-01</p> <p>Physical properties of the circumstellar <span class="hlt">dust</span> and associated physical mechanisms play an important role in understanding evolution of symbiotic binaries. We present a model of inner <span class="hlt">dust</span> regions around the cool Mira component of the two symbiotic novae, RR Tel and HM Sge, based on the long-term near-IR photometry, infrared ISO spectra and mid-IR interferometry. Pulsation properties and long-term variabilities were found from the near-IR light curves. The <span class="hlt">dust</span> properties were determined using the DUSTY code which solves the radiative transfer. No changes in pulsational parameters were found, but a long-term variations with periods of 20-25 years have been detected which cannot be attributed to orbital motion.Circumstellar silicate <span class="hlt">dust</span> shell with inner <span class="hlt">dust</span> shell temperatures between 900 K and 1300 K and of moderate optical depth can explain all the observations. RR Tel showed the presence of an optically thin CS <span class="hlt">dust</span> envelope and an optically thick <span class="hlt">dust</span> region outside the line of sight, which was further supported by the detailed modelling using the 2D LELUYA code. Obscuration events in RR Tel were explained by an increase in optical depth caused by the newly condensed <span class="hlt">dust</span> <span class="hlt">leading</span> to the formation of a compact <span class="hlt">dust</span> shell. HM Sge showed permanent obscuration and a presence of a compact <span class="hlt">dust</span> shell with a variable optical depth. Scattering of the near-IR colours can be understood by a change in sublimation temperature caused by the Mira variability. Presence of large <span class="hlt">dust</span> grains (up to 4 µm) suggests an increased grain growth in conditions of increased mass loss. The mass loss rates of up to 17·10-6 MSun/yr were significantly higher than in intermediate-period single Miras and in agreement with longer-period O-rich AGB stars.Despite the nova outburst, HM Sge remained enshrouded in <span class="hlt">dust</span> with no significant <span class="hlt">dust</span> destruction. The existence of unperturbed <span class="hlt">dust</span> shell suggests a small influence of the hot component and strong <span class="hlt">dust</span> shielding from the UV flux. By the use</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5535245','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5535245"><span>Eco-Friendly Acaricidal Effects of Nylon 66 Nanofibers via Grafted Clove Bud Oil-<span class="hlt">Loaded</span> Capsules on House <span class="hlt">Dust</span> Mites</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kim, Seong Hun</p> <p>2017-01-01</p> <p>Acaricidal nylon 66 fabrics (AN66Fs) grafted with clove oil-<span class="hlt">loaded</span> microcapsules (COMCs) were developed against Dermatophagoides farina (D. gallinae). The average diameter was about 2.9 µm with a range of 100 nm–8.5 µm. COMCs carried clove oil <span class="hlt">loading</span> of about 65 vol %. COMCs were chemically grafted to electrospun nylon nanofibers by the chemical reactions between –OH groups of COMCs and –COOH end groups of nylon fabrics to form ester linkages. AN66Fs had an effect on D. farinae depending on COMCs <span class="hlt">loadings</span>. The increase in COMCs <span class="hlt">loading</span> of AN66Fs from 5 to 15 wt % increased from 22% to 93% mortality against D. farinae within 72 h. However, AN66Fs containing over 20 wt % COMCs were more effective, showing up to 100% mortality within 24 h because the large amount of monoterpene alcohol, eugenol. This research suggests the use of clove oil and its major constituent eugenol as eco-friendly bioactive agents that can serve as a replacement for synthetic acaricides in controlling the population of D. farinae. PMID:28698512</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24369930','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24369930"><span>Inhalable <span class="hlt">dust</span> measurements as a first approach to assessing occupational exposure in the pharmaceutical industry.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Champmartin, C; Clerc, F</p> <p>2014-01-01</p> <p>Occupational exposure to active ingredients in the pharmaceutical industry has been the subject of very few published studies. Nevertheless, operations involving active powdered drugs or dusty operations potentially <span class="hlt">lead</span> to operator exposure. The aim of this study was to collect occupational exposure data in the pharmaceutical industry for production processes involving powdered active ingredients. While the possibility of assessing drug exposure from <span class="hlt">dust</span> level is examined, this article focuses on inhalable <span class="hlt">dust</span> exposure, without taking chemical risk into account. A total of 377 atmospheric (ambient and personal) samples were collected in nine drug production sites (pharmaceutical companies and contract manufacturing organizations) and the <span class="hlt">dust</span> levels were assessed. For each sample, relevant contextual information was collected. A wide range of results was observed, both site- and operation-dependent. Exposure to inhalable <span class="hlt">dust</span> levels varied from 0.01 mg/m(3)to 135 mg/m(3). Though restricted to <span class="hlt">dust</span> exposure, the study highlighted some potentially critical situations or operations, in particular manual tasks (<span class="hlt">loading</span>, unloading, mechanical actions) performed in open systems. Simple preventive measures such as ventilation, containment, and minimization of manual handling should reduce <span class="hlt">dust</span> emissions and workers' exposure to inhalable <span class="hlt">dust</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4137906','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4137906"><span>Size-Resolved <span class="hlt">Dust</span> and Aerosol Contaminants Associated with Copper and <span class="hlt">Lead</span> Smelting Emissions: Implications for Emissions Management and Human Health</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Csavina, Janae; Taylor, Mark P.; Félix, Omar; Rine, Kyle P.; Sáez, A. Eduardo; Betterton, Eric A.</p> <p>2014-01-01</p> <p>Mining operations, including crushing, grinding, smelting, refining, and tailings management, are a significant source of airborne metal and metalloid contaminants such as As, Pb and other potentially toxic elements. In this work, we show that size-resolved concentrations of As and Pb generally follow a bimodal distribution with the majority of contaminants in the fine size fraction (< 1 μm) around mining activities that include smelting operations at various sites in Australia and Arizona. This evidence suggests that contaminated fine particles (< 1 μm) are the result of vapor condensation and coagulation from smelting operations while coarse particles are most likely the result of windblown <span class="hlt">dust</span> from contaminated mine tailings and fugitive emissions from crushing and grinding activities. These results on the size distribution of contaminants around mining operations are reported to demonstrate the ubiquitous nature of this phenomenon so that more effective emissions management and practices that minimize health risks associated with metal extraction and processing can be developed. PMID:24995641</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24288065','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24288065"><span>Human health risk assessment based on trace metals in suspended air particulates, surface <span class="hlt">dust</span>, and floor <span class="hlt">dust</span> from e-waste recycling workshops in Hong Kong, China.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lau, Winifred Ka Yan; Liang, Peng; Man, Yu Bon; Chung, Shan Shan; Wong, Ming Hung</p> <p>2014-03-01</p> <p>This study investigated health risks exerted on electronic waste (e-waste) recycling workers exposed to cadmium (Cd), chromium (Cr), copper (Cu), <span class="hlt">lead</span> (Pb), nickel (Ni), mercury (Hg), and zinc (Zn) in Hong Kong. E-waste recycling workshops were classified into eight working areas: 1 = office, 2 = repair, 3 = dismantling, 4 = storage, 5 = desoldering, 6 = <span class="hlt">loading</span>, 7 = cable shredding, and 8 = chemical waste. The aforementioned metal concentrations were analyzed in suspended air particulates, surface <span class="hlt">dust</span> and floor <span class="hlt">dust</span> collected from the above study areas in five workshops. Elevated Pb levels were measured in dismantling and desoldering areas (582 and 486 μg/100 cm(2) in surface and 3,610 and 19,172 mg/kg in floor <span class="hlt">dust</span>, respectively). Blood <span class="hlt">lead</span> levels of 10 and 39.5 μg/dl were estimated using United States Environmental Protection Agency's Adult <span class="hlt">Lead</span> Model as a result of exposure to the floor <span class="hlt">dust</span> from these two areas. Human health risk assessments were conducted to evaluate cancer and noncancer risks resulting from exposure to floor <span class="hlt">dust</span> through the combined pathways of ingestion, dermal contact, and inhalation. Findings indicated that workers may be exposed to cancer risks above the acceptable range at 147 in a million at the 95th percentile in the dismantling area. Workers should be informed of associated risks to safeguard their health.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/8231799','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/8231799"><span>[Biological effect of wood <span class="hlt">dust</span>].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Maciejewska, A; Wojtczak, J; Bielichowska-Cybula, G; Domańska, A; Dutkiewicz, J; Mołocznik, A</p> <p>1993-01-01</p> <p>The biological effect of exposure to wood <span class="hlt">dust</span> depends on its composition and the content of microorganisms which are an inherent element of the <span class="hlt">dust</span>. The irritant and allergic effects of wood <span class="hlt">dust</span> have been recognised for a long time. The allergic effect is caused by the wood <span class="hlt">dust</span> of subtropical trees, e.g. western red cedar (Thuja plicata), redwood (Sequoia sempervirens), obeche (Triplochiton scleroxylon), cocabolla (Dalbergia retusa) and others. Trees growing in the European climate such as: larch (Larix), walnut (Juglans regia), oak (Quercus), beech (Fagus), pine (Pinus) cause a little less pronounced allergic effect. Occupational exposure to irritative or allergic wood <span class="hlt">dust</span> may <span class="hlt">lead</span> to bronchial asthma, rhinitis, alveolitis allergica, DDTS (Organic <span class="hlt">dust</span> toxic syndrome), bronchitis, allergic dermatitis, conjunctivitis. An increased risk of adenocarcinoma of the sinonasal cavity is an important and serious problem associated with occupational exposure to wood <span class="hlt">dust</span>. Adenocarcinoma constitutes about half of the total number of cancers induced by wood <span class="hlt">dust</span>. An increased incidence of the squamous cell cancers can also be observed. The highest risk of cancer applies to workers of the furniture industry, particularly those dealing with machine wood processing, cabinet making and carpentry. The cancer of the upper respiratory tract develops after exposure to many kinds of wood <span class="hlt">dust</span>. However, the wood <span class="hlt">dust</span> of oak and beech seems to be most carcinogenic. It is assumed that exposure to wood <span class="hlt">dust</span> can cause an increased incidence of other cancers, especially lung cancer and Hodgkin's disease. The adverse effects of microorganisms, mainly mould fungi and their metabolic products are manifested by alveolitis allergica and ODTS. These microorganisms can induce aspergillomycosis, bronchial asthma, rhinitis and allergic dermatitis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28082154','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28082154"><span><span class="hlt">Lead</span> Aprons Are a <span class="hlt">Lead</span> Exposure Hazard.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Burns, Kevin M; Shoag, Jamie M; Kahlon, Sukhraj S; Parsons, Patrick J; Bijur, Polly E; Taragin, Benjamin H; Markowitz, Morri</p> <p>2017-05-01</p> <p>To determine whether <span class="hlt">lead</span>-containing shields have <span class="hlt">lead</span> <span class="hlt">dust</span> on the external surface. Institutional review board approval was obtained for this descriptive study of a convenience sample of 172 shields. Each shield was tested for external <span class="hlt">lead</span> <span class="hlt">dust</span> via a qualitative rapid on-site test and a laboratory-based quantitative <span class="hlt">dust</span> wipe analysis, flame atomic absorption spectrometry (FAAS). The χ(2) test was used to test the association with age, type of shield, <span class="hlt">lead</span> sheet thickness, storage method, and visual and radiographic appearance. Sixty-three percent (95% confidence interval [CI]: 56%-70%) of the shields had detectable surface <span class="hlt">lead</span> by FAAS and 50% (95% CI: 43%-57%) by the qualitative method. <span class="hlt">Lead</span> <span class="hlt">dust</span> by FAAS ranged from undetectable to 998 μg/ft(2). The quantitative detection of <span class="hlt">lead</span> was significantly associated with the following: (1) visual appearance of the shield (1 = best, 3 = worst): 88% of shields that scored 3 had detectable <span class="hlt">dust</span> <span class="hlt">lead</span>; (2) type of shield: a greater proportion of the pediatric patient, full-body, and thyroid shields were positive than vests and skirts; (3) use of a hanger for storage: 27% of shields on a hanger were positive versus 67% not on hangers. Radiographic determination of shield intactness, thickness of interior <span class="hlt">lead</span> sheets, and age of shield were unrelated to presence of surface <span class="hlt">dust</span> <span class="hlt">lead</span>. Sixty-three percent of shields had detectable surface <span class="hlt">lead</span> that was associated with visual appearance, type of shield, and storage method. <span class="hlt">Lead</span>-containing shields are a newly identified, potentially widespread source of <span class="hlt">lead</span> exposure in the health industry. Copyright © 2016 American College of Radiology. Published by Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.C53C0864S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.C53C0864S"><span><span class="hlt">Dust</span> in Snow in the Colorado River Basin: Spatial Variability in <span class="hlt">Dust</span> Concentrations, Radiative Forcing, and Snowmelt Rates</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Skiles, M.; Painter, T.; Deems, J. S.; Landry, C.; Bryant, A.</p> <p>2012-12-01</p> <p>Since the disturbance of the western US that began with the Anglo settlement in the mid 19th century, the mountain snow cover of the Colorado River Basin (CRB) has been subject to five-fold greater <span class="hlt">dust</span> <span class="hlt">loading</span>. This <span class="hlt">dust</span> deposition accelerates snowmelt through its direct reduction of albedo and its further reduction of albedo by accelerating the growth of snow effective grain size. We have previously quantified the impacts of <span class="hlt">dust</span> in snow using a 6-year record of <span class="hlt">dust</span> concentration and energy balance fluxes at the alpine and subalpine towers in the Senator Beck Basin Study Area (SBBSA), San Juan Mountains in southwestern Colorado, USA. <span class="hlt">Dust</span> <span class="hlt">loading</span> exhibited interannual variability, and end of year <span class="hlt">dust</span> concentrations were not necessarily related to the number of <span class="hlt">dust</span> deposition events. Radiative forcing enhanced springtime melt by 21 to 51 days with the magnitude of advanced loss being linearly related to total <span class="hlt">dust</span> concentration at the end of snow cover. To expand our understanding of <span class="hlt">dust</span> on snow deposition patterns we utilize collections of <span class="hlt">dust</span> concentration at the Colorado <span class="hlt">Dust</span> on Snow (CODOS) study sites, established in 2009 along the western side of the CRB, to assess spatial variability in <span class="hlt">dust</span> <span class="hlt">loading</span>. In situ sampling of <span class="hlt">dust</span> stratigraphy and concentration occurs twice each season, once over peak snow water equivalent (15 April), and again during melt (15 May). <span class="hlt">Dust</span> <span class="hlt">loading</span> occurs at all sites; <span class="hlt">dust</span> concentrations are always higher in May, vary between sites, and the highest and lowest <span class="hlt">dust</span> years were 2009 and 2012, respectively. In the absence of regular sampling and energy balance instrumentation these sites do not allow us to quantify the advanced melt due to <span class="hlt">dust</span>. To facilitate this a new energy balance site, Grand Mesa Study plot (GMSP), was established for water year 2010 in west central Colorado, 150 km north of SBBSA. Back trajectories indicate similar Colorado Plateau <span class="hlt">dust</span> sources at both SBBSA and GMSP, yet GMSP exhibits slightly lower <span class="hlt">dust</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=253553','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=253553"><span>Mineralogical controls on <span class="hlt">dust</span> emissions in the Bodele Depression, Chad</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>Surface mineralogy is critical in the understanding of aeolian processes, however its role in <span class="hlt">dust</span> production is currently underestimated. Recent research indicates that discrepancies between predicted and observed <span class="hlt">dust</span> <span class="hlt">loads</span> by <span class="hlt">dust</span> models may be attributed to inadequacies within their associated d...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19900039965&hterms=sykes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dsykes','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19900039965&hterms=sykes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dsykes"><span><span class="hlt">Dust</span> bands in the asteroid belt</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sykes, Mark V.; Greenberg, Richard; Dermott, Stanley F.; Nicholson, Philip D.; Burns, Joseph A.</p> <p>1989-01-01</p> <p>This paper describes the original IRAS observations <span class="hlt">leading</span> to the discovery of the three <span class="hlt">dust</span> bands in the asteroid belt and the analysis of data. Special attention is given to an analytical model of the <span class="hlt">dust</span> band torus and to theories concerning the origin of the <span class="hlt">dust</span> bands, with special attention given to the collisional equilibrium (asteroid family), the nonequilibrium (random collision), and the comet hypotheses of <span class="hlt">dust</span>-band origin. It is noted that neither the equilibrium nor nonequilibrium models, as currently formulated, present a complete picture of the IRAS <span class="hlt">dust</span>-band observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25605712','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25605712"><span>Disruption of a conserved CAP-D3 threonine alters condensin <span class="hlt">loading</span> on mitotic chromosomes <span class="hlt">leading</span> to chromosome hypercondensation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bakhrebah, Muhammed; Zhang, Tao; Mann, Jeff R; Kalitsis, Paul; Hudson, Damien F</p> <p>2015-03-06</p> <p>The condensin complex plays a key role in organizing mitotic chromosomes. In vertebrates, there are two condensin complexes that have independent and cooperative roles in folding mitotic chromosomes. In this study, we dissect the role of a putative Cdk1 site on the condensin II subunit CAP-D3 in chicken DT40 cells. This conserved site has been shown to activate condensin II during prophase in human cells, and facilitate further phosphorylation by polo-like kinase I. We examined the functional significance of this phosphorylation mark by mutating the orthologous site of CAP-D3 (CAP-D3(T1403A)) in chicken DT40 cells. We show that this mutation is a gain of function mutant in chicken cells; it disrupts prophase, results in a dramatic shortening of the mitotic chromosome axis, and <span class="hlt">leads</span> to abnormal INCENP localization. Our results imply phosphorylation of CAP-D3 acts to limit condensin II binding onto mitotic chromosomes. We present the first in vivo example that alters the ratio of condensin I:II on mitotic chromosomes. Our results demonstrate this ratio is a critical determinant in shaping mitotic chromosomes. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4358255','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4358255"><span>Disruption of a Conserved CAP-D3 Threonine Alters Condensin <span class="hlt">Loading</span> on Mitotic Chromosomes <span class="hlt">Leading</span> to Chromosome Hypercondensation*</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Bakhrebah, Muhammed; Zhang, Tao; Mann, Jeff R.; Kalitsis, Paul; Hudson, Damien F.</p> <p>2015-01-01</p> <p>The condensin complex plays a key role in organizing mitotic chromosomes. In vertebrates, there are two condensin complexes that have independent and cooperative roles in folding mitotic chromosomes. In this study, we dissect the role of a putative Cdk1 site on the condensin II subunit CAP-D3 in chicken DT40 cells. This conserved site has been shown to activate condensin II during prophase in human cells, and facilitate further phosphorylation by polo-like kinase I. We examined the functional significance of this phosphorylation mark by mutating the orthologous site of CAP-D3 (CAP-D3T1403A) in chicken DT40 cells. We show that this mutation is a gain of function mutant in chicken cells; it disrupts prophase, results in a dramatic shortening of the mitotic chromosome axis, and <span class="hlt">leads</span> to abnormal INCENP localization. Our results imply phosphorylation of CAP-D3 acts to limit condensin II binding onto mitotic chromosomes. We present the first in vivo example that alters the ratio of condensin I:II on mitotic chromosomes. Our results demonstrate this ratio is a critical determinant in shaping mitotic chromosomes. PMID:25605712</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017A%26A...601A..52B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017A%26A...601A..52B"><span>A new view on the M 87 jet origin: Turbulent <span class="hlt">loading</span> <span class="hlt">leading</span> to large-scale episodic wiggling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Britzen, S.; Fendt, C.; Eckart, A.; Karas, V.</p> <p>2017-05-01</p> <p> opening angle. In this paper we present evidence for two different operating modes of the jet of M 87. The jet switches between two phases: i) the jet ridge line is at least double or the jet axis is displaced vertically, and ii) an unperturbed phase where the jet ridge line remains almost straight but is smoothly curved and the jet components are aligned along a classical jet axis. The mode change occurs every couple of years. Between the two operating modes, a transition phase is visible. Conclusions: The M 87 jet visible at 15 GHz probes a different physical zone compared to the standard blazar-zone we tend to see in AGN jets. The most likely scenario explaining the observed phenomena is a turbulent mass <span class="hlt">loading</span> into the jet, most probably due to local, fast reconnection processes driven by turbulence of a tangled magnetic field, which is either generated in the accretion disk or the disk corona. In addition, on large scales, a global magnetic structure is required to channel the turbulent flow into what evolves into a large-scale jet. Large-scale jet instabilities may explain the curved pattern of the observed jet flow.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24631974','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24631974"><span>On the link between biomagnetic monitoring and leaf-deposited <span class="hlt">dust</span> <span class="hlt">load</span> of urban trees: relationships and spatial variability of different particle size fractions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hofman, Jelle; Wuyts, Karen; Van Wittenberghe, Shari; Brackx, Melanka; Samson, Roeland</p> <p>2014-06-01</p> <p>Biomagnetic monitoring of urban tree leaves has proven to be a good estimator of ambient particulate matter. We evaluated its relevancy by determining leaf area normalised weight (mg m(-2)) and SIRM (A) of leaf-deposited particles within three different size fractions (>10 μm, 3-10 μm and 0.2-3 μm) and the SIRM of the leaf-encapsulated particles. Results showed that throughout the in-leaf season, the trees accumulated on average 747 mg m(-2) of <span class="hlt">dust</span> on their leaves, of which 74 mg m(-2) was within the 0.2-10 μm (∼PM10) size range and 40 mg m(-2) within the 0.2-3 μm (∼PM3) size range. A significant correlation between the SIRM and weight of the surface-deposited particles confirms the potential of biomagnetic monitoring as a proxy for the amount of leaf-deposited particles. Spatial variation of both SIRM and weight throughout the street canyon suggests traffic and wind as key factors for respectively the source and distribution of urban particulates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24890181','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24890181"><span>Reprint of On the link between biomagnetic monitoring and leaf-deposited <span class="hlt">dust</span> <span class="hlt">load</span> of urban trees: relationships and spatial variability of different particle size fractions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hofman, Jelle; Wuyts, Karen; Van Wittenberghe, Shari; Brackx, Melanka; Samson, Roeland</p> <p>2014-09-01</p> <p>Biomagnetic monitoring of urban tree leaves has proven to be a good estimator of ambient particulate matter. We evaluated its relevancy by determining leaf area normalised weight (mg m(-2)) and SIRM (A) of leaf-deposited particles within three different size fractions (>10 μm, 3-10 μm and 0.2-3 μm) and the SIRM of the leaf-encapsulated particles. Results showed that throughout the in-leaf season, the trees accumulated on average 747 mg m(-2) of <span class="hlt">dust</span> on their leaves, of which 74 mg m(-2) was within the 0.2-10 μm (∼PM10) size range and 40 mg m(-2) within the 0.2-3 μm (∼PM3) size range. A significant correlation between the SIRM and weight of the surface-deposited particles confirms the potential of biomagnetic monitoring as a proxy for the amount of leaf-deposited particles. Spatial variation of both SIRM and weight throughout the street canyon suggests traffic and wind as key factors for respectively the source and distribution of urban particulates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22370634','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22370634"><span>Newton to Einstein — <span class="hlt">dust</span> to <span class="hlt">dust</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kopp, Michael; Uhlemann, Cora; Haugg, Thomas E-mail: cora.uhlemann@physik.lmu.de</p> <p>2014-03-01</p> <p>We investigate the relation between the standard Newtonian equations for a pressureless fluid (<span class="hlt">dust</span>) and the Einstein equations in a double expansion in small scales and small metric perturbations. We find that parts of the Einstein equations can be rewritten as a closed system of two coupled differential equations for the scalar and transverse vector metric perturbations in Poisson gauge. It is then shown that this system is equivalent to the Newtonian system of continuity and Euler equations. Brustein and Riotto (2011) conjectured the equivalence of these systems in the special case where vector perturbations were neglected. We show that this approach does not <span class="hlt">lead</span> to the Euler equation but to a physically different one with large deviations already in the 1-loop power spectrum. We show that it is also possible to consistently set to zero the vector perturbations which strongly constrains the allowed initial conditions, in particular excluding Gaussian ones such that inclusion of vector perturbations is inevitable in the cosmological context. In addition we derive nonlinear equations for the gravitational slip and tensor perturbations, thereby extending Newtonian gravity of a <span class="hlt">dust</span> fluid to account for nonlinear light propagation effects and <span class="hlt">dust</span>-induced gravitational waves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/118856','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/118856"><span>Steelworks <span class="hlt">dust</span> -- From waste to product</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Strohmeier, G.; Bonestell, J.E.</p> <p>1995-07-01</p> <p>Scrap-borne zinc and <span class="hlt">lead</span> are enriched in the electric arc furnace <span class="hlt">dusts</span>. Its Pb/Zn content of over 20% renders the dumping of this <span class="hlt">dust</span> impossible in many countries, for both statutory and financial reasons. The Waelz process is the only reliable large-scale method for processing such <span class="hlt">dusts</span>. 45% of the total electric furnace <span class="hlt">dusts</span> occurring throughout Europe are being processed in Waelz plants with several operating in the US. The <span class="hlt">dust</span> is treated in a rotary kiln where it is heated to approximately 1,200 C. <span class="hlt">Lead</span> and zinc are volatilized under reducing conditions and collected as fine <span class="hlt">dust</span> from the off-gas by cooling. The Waelz oxide recovered in the off-gas filters contains approximately 55% Zn and up to 10% Pb, and is ideal feedstock for the Imperial Smelting furnace for <span class="hlt">lead</span>/zinc recovery. The remaining slag is inert and unleachable so that it can be used as a building aggregate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007JGRD..11216208Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007JGRD..11216208Z"><span><span class="hlt">Dust</span> plumes over the Pacific, Indian, and Atlantic oceans: Climatology and radiative impact</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhu, Aihua; Ramanathan, V.; Li, Fang; Kim, Dohyeong</p> <p>2007-08-01</p> <p>Multiple satellite data sets in conjunction with the Monte Carlo Aerosol-Cloud-Radiation (MACR) model are employed to determine climatological distributions and radiative impacts of <span class="hlt">dust</span> plumes over the Pacific, Indian, and Atlantic oceans. Three target regions, namely the Yellow Sea (YS), Arabian Sea (AS), and Saharan Coast (SC), are examined for quantitative comparisons of <span class="hlt">dust</span> properties and their impacts on climate. Twenty year averaged Advanced Very High Resolution Radiometer (AVHRR) aerosol optical depth (AOD) data clearly show the peak <span class="hlt">dust</span> season for the three target regions, March-April-May for YS and June-July-August for AS and SC. Georgia Institute of Technology-Goddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) modeled <span class="hlt">dust</span> AOD fraction and Moderate Imaging Spectroradiometer (MODIS) large-mode AOD ratio are adopted to evaluate the <span class="hlt">dust</span> fraction estimate. Stratospheric Aerosol and Gas Experiment (SAGE) II aerosol extinction coefficient data are used to define the vertical distribution of <span class="hlt">dust</span>. The elevated <span class="hlt">dust</span> plumes are detected by subtracting the non-<span class="hlt">dust</span>-season values from <span class="hlt">dust</span> season values of SAGE II data, showing extinction peak around ˜4 km over AS and SC. Over YS, <span class="hlt">dust</span> plumes are found presenting multilayered structure. The shortwave (SW) forcing of <span class="hlt">dust</span>, although moderated by the longwave (LW) effect, dominates the net effects (SW + LW) of <span class="hlt">dust</span> plumes. Under clear-sky (i.e., cloudless) conditions, <span class="hlt">dust</span> plumes reduce about 5.9 W m-2, 17.8 W m-2, and 14.2 W m-2 regional and seasonal mean radiative flux reaching the surface over YS, AS, and SC, respectively. Of the three regions, <span class="hlt">dust</span> plumes over AS have the largest effect on atmospheric heating owing to a lower single-scattering albedo and the relatively large <span class="hlt">dust</span> <span class="hlt">loading</span>. The maximum SW heating occurs over AS with the value around +0.5 K/day inside the <span class="hlt">dust</span> layer at ˜4 km. The LW effect results in strong cooling throughout the <span class="hlt">dust</span> layer and moderate heating below the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008GeoRL..35.8710C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008GeoRL..35.8710C"><span><span class="hlt">Dust</span> and sea surface temperature forcing of the 1930s ``<span class="hlt">Dust</span> Bowl'' drought</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cook, Benjamin I.; Miller, Ron L.; Seager, Richard</p> <p>2008-04-01</p> <p>Droughts over the central United States (US) are modulated by sea surface temperature (SST) variations in the eastern tropical Pacific. Many models, however, are unable to reproduce the severity and spatial pattern of the ``<span class="hlt">Dust</span> Bowl'' drought of the 1930s with SST forcing alone. We force an atmosphere general circulation model with 1930s SSTs and model-generated <span class="hlt">dust</span> emission from the Great Plains region. The SSTs alone force a drought over the US similar to observations, but with a weaker precipitation anomaly that is centered too far south. Inclusion of <span class="hlt">dust</span> radiative forcing, centered over the area of observed wind erosion, increases the intensity of the drought and shifts its center northward. While our conclusions are tempered by limited quantitative observations of the <span class="hlt">dust</span> aerosol <span class="hlt">load</span> and soil erosion during this period, our study suggests that unprecedented atmospheric <span class="hlt">dust</span> <span class="hlt">loading</span> over the continental US exacerbated the ``<span class="hlt">Dust</span> Bowl'' drought.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17285256','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17285256"><span>Chemical constituents of fugitive <span class="hlt">dust</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Van Pelt, R Scott; Zobeck, Ted M</p> <p>2007-07-01</p> <p>Wind erosion selectively winnows the fine, most chemically concentrated portions of surface soils and results in the inter-regional transport of fugitive <span class="hlt">dust</span> containing plant nutrients, trace elements and other soil-borne contaminants. We sampled and analyzed surface soils, sediments in transport over eroding fields, and attic <span class="hlt">dust</span> from a small area of the Southern High Plains of Texas to characterize the physical nature and chemical constituents of these materials and to investigate techniques that would allow relatively rapid, low cost techniques for estimating the chemical constituents of fugitive <span class="hlt">dust</span> from an eroding field. From chemical analyses of actively eroding sediments, it would appear that Ca is the only chemical species that is enriched more than others during the process of fugitive <span class="hlt">dust</span> production. We found surface soil sieved to produce a sub-sample with particle diameters in the range of 53-74 microm to be a reasonably good surrogate for fugitive <span class="hlt">dust</span> very near the source field, that sieved sub-samples with particle diameters <10 microm have a crustal enrichment factor of approximately 6, and that this factor, multiplied by the chemical contents of source soils, may be a reasonable estimator of fugitive PM(10) chemistry from the soils of interest. We also found that <span class="hlt">dust</span> from tractor air cleaners provided a good surrogate for <span class="hlt">dust</span> entrained by tillage and harvesting operations if the chemical species resulting from engine wear and exhaust were removed from the data set or scaled back to the average of enrichment factors noted for chemical species with no known anthropogenic sources. Chemical analyses of <span class="hlt">dust</span> samples collected from attics approximately 4 km from the nearest source fields indicated that anthropogenic sources of several environmentally important nutrient and trace element species are much larger contributors, by up to nearly two orders of magnitude, to atmospheric <span class="hlt">loading</span> and subsequent deposition than fugitive <span class="hlt">dust</span> from eroding</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008WRR....44.5202H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008WRR....44.5202H"><span><span class="hlt">Dust</span>-rainfall feedbacks in the West African Sahel</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hui, Wanching Jacquie; Cook, Benjamin I.; Ravi, Sujith; Fuentes, José D.; D'Odorico, Paolo</p> <p>2008-05-01</p> <p><span class="hlt">Dust</span> aerosols can suppress rainfall by increasing the number of cloud condensation nuclei in warm clouds and affecting the surface radiation budget and boundary layer instability. The extent to which atmospheric <span class="hlt">dust</span> may affect precipitation yields and the hydrologic cycle in semiarid regions remains poorly understood. We investigate the relationship between <span class="hlt">dust</span> aerosols and rainfall in the West African Sahel where the <span class="hlt">dust</span>-rainfall feedback has been speculated to contribute to sustained droughts. We find that the amount of <span class="hlt">dust</span> <span class="hlt">loadings</span> is negatively correlated with rainfall values, suggesting that <span class="hlt">dust</span> entrained in the atmosphere can significantly inhibit rainfall in this region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998PhLA..244..557D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998PhLA..244..557D"><span>Damping of <span class="hlt">dust</span>-acoustic waves due to <span class="hlt">dust-dust</span> interactions in dusty plasmas</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>de Angelis, U.; Shukla, P. K.</p> <p>1998-08-01</p> <p>The results of a kinetic model are presented which includes <span class="hlt">dust-dust</span> collisions as a damping mechanism for the low-phase velocity <span class="hlt">dust</span>-acoustic waves which have been observed [Pieper and Goree, Phys. Rev. Lett. 77 (1976) 3137] in a dusty plasma device. A comparison of our theoretical results with those of observations exhibits a good agreement, and it also <span class="hlt">leads</span> to quantitative estimates that are close to the predictions of the modified fluid theory, which has introduced a damping rate in an ad hoc manner.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11308955','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11308955"><span>Effect of nonadiabaticity of <span class="hlt">dust</span> charge variation on <span class="hlt">dust</span> acoustic waves: generation of <span class="hlt">dust</span> acoustic shock waves.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gupta, M R; Sarkar, S; Ghosh, S; Debnath, M; Khan, M</p> <p>2001-04-01</p> <p>The effect of nonadiabaticity of <span class="hlt">dust</span> charge variation arising due to small nonzero values of tau(ch)/tau(d) has been studied where tau(ch) and tau(d) are the <span class="hlt">dust</span> charging and <span class="hlt">dust</span> hydrodynamical time scales on the nonlinear propagation of <span class="hlt">dust</span> acoustic waves. Analytical investigation shows that the propagation of a small amplitude wave is governed by a Korteweg-de Vries (KdV) Burger equation. Notwithstanding the soliton decay, the "soliton mass" is conserved, but the dissipative term <span class="hlt">leads</span> to the development of a noise tail. Nonadiabaticity generated dissipative effect causes the generation of a <span class="hlt">dust</span> acoustic shock wave having oscillatory behavior on the downstream side. Numerical investigations reveal that the propagation of a large amplitude <span class="hlt">dust</span> acoustic shock wave with <span class="hlt">dust</span> density enhancement may occur only for Mach numbers lying between a minimum and a maximum value whose dependence on the dusty plasma parameters is presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2000/0322/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2000/0322/report.pdf"><span>Concentrations and <span class="hlt">loads</span> of cadmium, <span class="hlt">lead</span>, and zinc measured near the peak of the 1999 snowmelt-runoff hydrographs for 42 water-quality stations, Coeur d'Alene River basin, Idaho</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Woods, Paul F.</p> <p>2000-01-01</p> <p>The Coeur d’Alene River near Harrison transported 924 pounds of dissolved <span class="hlt">lead</span> per day, of which 82.8 pounds came from the South Fork and 11.7 pounds from the North Fork. Only 10.2 percent of the <span class="hlt">load</span> at Harrison was measured at the Pinehurst and Enaville stations; therefore, a substantial <span class="hlt">load</span> of dissolved <span class="hlt">lead</span> is being contributed downstream from the confluence of the North and South Forks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22305094','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22305094"><span>Microbial communities associated with house <span class="hlt">dust</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rintala, Helena; Pitkäranta, Miia; Täubel, Martin</p> <p>2012-01-01</p> <p>House <span class="hlt">dust</span> is a complex mixture of inorganic and organic material with microbes in abundance. Few microbial species are actually able to grow and proliferate in <span class="hlt">dust</span> and only if enough moisture is provided. Hence, most of the microbial content originates from sources other than the <span class="hlt">dust</span> itself. The most important sources of microbes in house <span class="hlt">dust</span> are outdoor air and other outdoor material tracked into the buildings, occupants of the buildings including pets and microbial growth on moist construction materials. Based on numerous cultivation studies, Penicillium, Aspergillus, Cladosporium, and about 20 other fungal genera are the most commonly isolated genera from house <span class="hlt">dust</span>. The cultivable bacterial flora is dominated by Gram-positive genera, such as Staplylococcus, Corynebacterium, and Lactococcus. Culture-independent studies have shown that both the fungal and the bacterial flora are far more diverse, with estimates of up to 500-1000 different species being present in house <span class="hlt">dust</span>. Concentrations of microbes in house <span class="hlt">dust</span> vary from nondetectable to 10(9) cells g(-1) <span class="hlt">dust</span>, depending on the <span class="hlt">dust</span> type, detection method, type of the indoor environment and season, among other factors. Microbial assemblages in different house <span class="hlt">dust</span> types usually share the same core species; however, alterations in the composition are caused by differing sources of microbes for different <span class="hlt">dust</span> types. For example, mattress <span class="hlt">dust</span> is dominated by species originating from the user of the mattress, whereas floor <span class="hlt">dust</span> reflects rather outdoor sources. Farming homes contain higher microbial <span class="hlt">load</span> than urban homes and according to a recent study, temperate climate zones show higher <span class="hlt">dust</span> microbial diversity than tropical zones.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70021418','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70021418"><span><span class="hlt">Dust</span> devil vortices seen by the Mars Pathfinder camera</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Metzger, S.M.; Carr, J.R.; Johnson, J. R.; Parker, T.J.; Lemmon, M.T.</p> <p>1999-01-01</p> <p>Discovery of <span class="hlt">dust</span> devil vortices in Mars Pathfinder (MPF) images reveals a <span class="hlt">dust</span> entrainment mechanism at work on Mars. Scattering of visible light by <span class="hlt">dust</span> in the Martian atmosphere creates a pronounced haze, preventing conventional image processing from displaying <span class="hlt">dust</span> plumes. Spectral differencing techniques have enhanced five localized <span class="hlt">dust</span> plumes from the general haze in images acquired near midday, which we determine to be <span class="hlt">dust</span> devils. Processing of 440 nm images highlights <span class="hlt">dust</span> devils as distinct occultation features against the horizon. The <span class="hlt">dust</span> devils are interpreted to be 14-79 m wide, 46-350 m tall, travel at 0.5-4.6 m/s, with <span class="hlt">dust</span> <span class="hlt">loading</span> of 7E-5 kg m-3, relative to the general haze of 9E-8 kg m-3, and total particulate transport of 2.2 - 700 kg. The vortices match predictions from terrestrial analog studies. Copyright 1999 by the American Geophysical Union.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014Icar..231..385M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014Icar..231..385M"><span>The retrieval of optical properties from terrestrial <span class="hlt">dust</span> devil vortices</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mason, Jonathon P.; Patel, Manish R.; Lewis, Stephen R.</p> <p>2014-03-01</p> <p>The retrieval of the optical properties of desert aerosols in suspension within terrestrial <span class="hlt">dust</span> devils is presented with possible future application for martian <span class="hlt">dust</span> devils. The transmission of light through <span class="hlt">dust</span> devil vortices was measured in situ to obtain the wavelength-dependent attenuation by the aerosols. A Monte Carlo model was applied to each <span class="hlt">dust</span> devil with the retrieved optical properties corresponding to the set of parameters which <span class="hlt">lead</span> to the best model representation of the observed transmission spectra. The retrieved optical properties agree well with single scattering theory and are consistent with previous studies of <span class="hlt">dust</span> aerosols. The enhanced absorption observed for <span class="hlt">dust</span> devils with a higher tangential wind speed, and in comparison to atmospheric aerosol studies, suggests that larger <span class="hlt">dust</span> particles are lofted and suspended around <span class="hlt">dust</span> devil vortices. This analysis has shown that the imaginary refractive indices (and thus the optical properties of the suspended <span class="hlt">dust</span>) are generally overestimated when these larger <span class="hlt">dust</span> grains entrained by <span class="hlt">dust</span> devils are neglected. This will <span class="hlt">lead</span> to an overestimation of the amount of solar radiation absorbed by the small particles that remain in suspension after the <span class="hlt">dust</span> devil terminates. It is also demonstrated that a 10% uncertainty in the particle size distribution of the <span class="hlt">dust</span> entrained in the <span class="hlt">dust</span> devils can result in a 50% increase in the predicted amount of incident solar radiation absorbed by the <span class="hlt">dust</span> particles once the <span class="hlt">dust</span> devil has terminated. The method used here provides the capability to retrieve the optical properties of the <span class="hlt">dust</span> entrained in martian <span class="hlt">dust</span> devils by taking advantage of transits over surface spacecraft which are capable of making optical measurements at ultraviolet and visible wavelengths. Our results suggest that we would observed higher absorption at all wavelengths for <span class="hlt">dust</span> particles entrained in <span class="hlt">dust</span> devil vortices compared to the ubiquitous <span class="hlt">dust</span> haze.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=280601','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=280601"><span><span class="hlt">Dust</span> cyclone technology for gins – A literature review</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p><span class="hlt">Dust</span> cyclone research <span class="hlt">leading</span> to more efficient designs has helped the cotton ginning industry to comply with increasingly stringent air quality regulations governing fine particulate emissions. Future changes in regulations may require additional improvements in <span class="hlt">dust</span> cyclone efficacy. This inter-...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SSRv..203...89F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SSRv..203...89F"><span>Orbital Observations of <span class="hlt">Dust</span> Lofted by Daytime Convective Turbulence</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fenton, Lori; Reiss, Dennis; Lemmon, Mark; Marticorena, Béatrice; Lewis, Stephen; Cantor, Bruce</p> <p>2016-11-01</p> <p>Over the past several decades, orbital observations of lofted <span class="hlt">dust</span> have revealed the importance of mineral aerosols as a climate forcing mechanism on both Earth and Mars. Increasingly detailed and diverse data sets have provided an ever-improving understanding of <span class="hlt">dust</span> sources, transport pathways, and sinks on both planets, but the role of <span class="hlt">dust</span> in modulating atmospheric processes is complex and not always well understood. We present a review of orbital observations of entrained <span class="hlt">dust</span> on Earth and Mars, particularly that produced by the <span class="hlt">dust</span>-laden structures produced by daytime convective turbulence called "<span class="hlt">dust</span> devils". On Earth, <span class="hlt">dust</span> devils are thought to contribute only a small fraction of the atmospheric <span class="hlt">dust</span> budget; accordingly, there are not yet any published accounts of their occurrence from orbit. In contrast, <span class="hlt">dust</span> devils on Mars are thought to account for several tens of percent of the planet's atmospheric <span class="hlt">dust</span> budget; the literature regarding martian <span class="hlt">dust</span> devils is quite rich. Because terrestrial <span class="hlt">dust</span> devils may temporarily contribute significantly to local <span class="hlt">dust</span> <span class="hlt">loading</span> and lowered air quality, we suggest that martian <span class="hlt">dust</span> devil studies may inform future studies of convectively-lofted <span class="hlt">dust</span> on Earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20080037975&hterms=PAH&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DPAH','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20080037975&hterms=PAH&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DPAH"><span>The Cosmic Odyssey of <span class="hlt">Dust</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dwek, Eli</p> <p>2008-01-01</p> <p>We will present models for the evolution of <span class="hlt">dust</span> in high redshift galaxies and in galaxies in the local universe. Galaxies at very high redshift, when the universe was less than one billion years old, contain massive quantities of <span class="hlt">dust</span> that could only have fornedin the explosion of core-collapse supernovae. These same objects are also the main source of grain destruction during the later, remnant phase of their evolution. These galaxies offer therefore a unique opportunity for examining the effect of massive stars on the formation and destruction of interstellar <span class="hlt">dust</span>, and the lecture will present a model for the evolution of <span class="hlt">dust</span> in these very young galaxies. Spectral and photometric observations of nearby galaxies show a correlation between the strength of their mid-IR aromatic features, attributed to PAH molecules, and their metal abundance, <span class="hlt">leading</span> to a deficiency of these features in low-metallicity galaxies. We show the observed correlation represents a trend of PAH abundance with galactic age, reflecting the delayed injection of carbon <span class="hlt">dust</span> into the ISM by AGB stars in the final post-AGB phase of their evolution. We also show that larger <span class="hlt">dust</span> particles giving rise to the far-IR emission follow a distinct evolutionary trend closely related to the injection of <span class="hlt">dust</span> by massive stars into the ISM.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/653168','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/653168"><span>The impact of low technology <span class="hlt">lead</span> hazard reduction activities among children with mildly elevated blood <span class="hlt">lead</span> levels</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Aschengrau, A.; Hardy, S.; Mackey, P.; Pultinas, D.</p> <p>1998-10-01</p> <p>This prospective environmental intervention study was conducted to determine the impact of low-technology <span class="hlt">lead</span> hazard reduction activities among children with mildly elevated blood <span class="hlt">lead</span> levels. Children whose homes had severe <span class="hlt">lead</span> hazards were automatically assigned to the intervention group. Children whose homes had lesser hazards were randomly assigned to the intervention group or comparison group. The one-time intervention focused mainly on cleaning and repainting window areas and educating caregivers to maintain effective housekeeping techniques. Changes in blood <span class="hlt">lead</span> and <span class="hlt">dust</span> <span class="hlt">lead</span> <span class="hlt">loading</span> levels were observed following the interventions. Analysis of covariance was used to adjust comparisons of postintervention levels for preintervention levels and other variables. The <span class="hlt">lead</span> hazard reduction activities were associated with a modest decline in blood <span class="hlt">lead</span> levels among children with severe hazards. The magnitude of the decline depended on the confounder that was controlled; the majority ranged from {minus}1.1 to {minus}1.6 {micro}g/dL. A moderate reduction in window well <span class="hlt">dust</span> <span class="hlt">lead</span> <span class="hlt">loading</span> levels was also observed. While low-technology <span class="hlt">lead</span> hazard reduction measures appeared to be an effective secondary prevention strategy among children with severe household <span class="hlt">lead</span> hazards, larger studies are needed to confirm these results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.A21E0112C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.A21E0112C"><span>Wet <span class="hlt">Dust</span> Deposition Across Texas, USA</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Collins, J. D., Jr.; Ponette-González, A.; Gill, T. E.; Glass, G. A.; Weathers, K. C.</p> <p>2016-12-01</p> <p>Atmospheric <span class="hlt">dust</span> deposition is of critical importance in terrestrial biogeochemical cycles, supplying essential limiting nutrients, such as calcium and phosphorus as well as pollutants, such as <span class="hlt">lead</span>, to ecosystems. <span class="hlt">Dust</span> particles are delivered to terrestrial ecosystems directly as dry deposition or in precipitation (wet deposition) as a result of rainout (particles incorporated into cloud droplets) and washout (particles that collide with raindrops as they fall). Compared to dry deposition, wet <span class="hlt">dust</span> deposition (dissolved + particulate) is a poorly understood yet potentially significant pathway for <span class="hlt">dust</span> input, especially in humid regions. We quantified wet <span class="hlt">dust</span> deposition to two National Atmospheric Deposition Monitoring (NADP) sites across Texas-one in west (Guadalupe Mountains) and one in east (near Houston) Texas-with contrasting climate/<span class="hlt">dust</span> regimes and land cover. We focused on 2012 during one of the most severe droughts in Texas since 1895. <span class="hlt">Dust</span> event days (DEDs) were identified using meteorological data for stations within 150 km of the NADP sites where wet deposition was sampled weekly. DEDs were defined using the following criteria: visibility <10 km, <30% relative humidity, and wind speed >50 km, supplemented with other Saharan <span class="hlt">dust</span> incursion and <span class="hlt">dust</span> observations. A total of 34 DEDs (20 sample weeks) were identified for the west and 5 DEDs (4 sample weeks) for the east Texas sites. Bulk elemental composition of washout particles is analyzed using Particle Induced X-ray Emission (PIXE) spectroscopy and X-ray Fluorescence (XRF) spectroscopy. Using these data, we will examine differences in the chemical composition of rainwater and aerosol particles filtered from rain samples for <span class="hlt">dust</span> versus non-<span class="hlt">dust</span> event days at each study site. Deposition fluxes for <span class="hlt">dust</span> and non-<span class="hlt">dust</span> event weeks are also compared. Quantifying the magnitude of wet <span class="hlt">dust</span> deposition is necessary to improve evaluation of <span class="hlt">dust</span> impacts on biogeochemical cycles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ISPAr.XL2..151X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ISPAr.XL2..151X"><span>An automated and integrated framework for <span class="hlt">dust</span> storm detection based on ogc web processing services</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xiao, F.; Shea, G. Y. K.; Wong, M. S.; Campbell, J.</p> <p>2014-11-01</p> <p><span class="hlt">Dust</span> storms are known to have adverse effects on public health. Atmospheric <span class="hlt">dust</span> <span class="hlt">loading</span> is also one of the major uncertainties in global climatic modelling as it is known to have a significant impact on the radiation budget and atmospheric stability. The complexity of building scientific <span class="hlt">dust</span> storm models is coupled with the scientific computation advancement, ongoing computing platform development, and the development of heterogeneous Earth Observation (EO) networks. It is a challenging task to develop an integrated and automated scheme for <span class="hlt">dust</span> storm detection that combines Geo-Processing frameworks, scientific models and EO data together to enable the <span class="hlt">dust</span> storm detection and tracking processes in a dynamic and timely manner. This study develops an automated and integrated framework for <span class="hlt">dust</span> storm detection and tracking based on the Web Processing Services (WPS) initiated by Open Geospatial Consortium (OGC). The presented WPS framework consists of EO data retrieval components, <span class="hlt">dust</span> storm detecting and tracking component, and service chain orchestration engine. The EO data processing component is implemented based on OPeNDAP standard. The <span class="hlt">dust</span> storm detecting and tracking component combines three earth scientific models, which are SBDART model (for computing aerosol optical depth (AOT) of <span class="hlt">dust</span> particles), WRF model (for simulating meteorological parameters) and HYSPLIT model (for simulating the <span class="hlt">dust</span> storm transport processes). The service chain orchestration engine is implemented based on Business Process Execution Language for Web Service (BPEL4WS) using open-source software. The output results, including horizontal and vertical AOT distribution of <span class="hlt">dust</span> particles as well as their transport paths, were represented using KML/XML and displayed in Google Earth. A serious <span class="hlt">dust</span> storm, which occurred over East Asia from 26 to 28 Apr 2012, is used to test the applicability of the proposed WPS framework. Our aim here is to solve a specific instance of a complex EO data</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3847858','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3847858"><span>Allostatic <span class="hlt">load</span> amplifies the effect of blood <span class="hlt">lead</span> levels on elevated blood pressure among middle-aged U.S. adults: a cross-sectional study</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2013-01-01</p> <p>Background Scientists and regulators have sought to understand whether and how physiologic dysregulation due to chronic stress exposure may enhance vulnerability to the adverse health effects of toxicant exposures. We conducted a cross-sectional study to determine whether allostatic <span class="hlt">load</span> (AL), a composite measure of physiologic response to chronic exposure to stress, amplifies the effect of <span class="hlt">lead</span> exposure on blood pressure among middle-aged adults. Methods We analyzed associations between blood <span class="hlt">lead</span> levels and blood pressure in a nationally representative sample of 8,194 U.S. adults (aged 40-65 years) participating in the National Health and Nutritional Examination Survey, 1999--2008. Outcomes were elevated systolic (≥ 140 mm Hg) and diastolic (≥ 90 mm Hg) blood pressure. AL was defined as the aggregate score of seven components, reflecting dysregulation of the cardiovascular, inflammatory, and endocrine systems. Results Logistic regression models showed a linear dose-response relationship for quintiles of blood <span class="hlt">lead</span> and elevated systolic blood pressure in the high AL group (p = 0.03) but not the low AL group (p = 0.24). Similarly, the relationship between <span class="hlt">lead</span> exposure and elevated diastolic blood pressure was stronger among the high AL group than the low AL group. Within the high AL group, the fourth and fifth quintiles had significantly elevated odds of elevated blood pressure compared to lowest quintile [OR = 1.92, (95% CI, 1.07, 3.47) and OR =2.28 (95% CI, 1.33, 3.91), respectively]. In the low AL group, none of the quintile effects were significantly different than the referent group although there was evidence of a linear trend (p =0.03). The <span class="hlt">lead</span> by AL interaction term was not statistically significant for either systolic or diastolic blood pressure models. Conclusions Results suggest that higher AL may amplify the adverse effects of <span class="hlt">lead</span> on blood pressure. Future research should assess the implications of cumulative exposures to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFM.A71E..01W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFM.A71E..01W"><span>Status and Future of <span class="hlt">Dust</span> Storm Forecasting</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Westphal, D. L.</p> <p>2002-12-01</p> <p>In recent years, increased attention has been given to the large amounts of airborne <span class="hlt">dust</span> derived from the deserts and desertified areas of the world and transported over scales ranging from local to global. This <span class="hlt">dust</span> can have positive and negative impacts on human activities and the environment, including modifying cloud formation, fertilizing the ocean, degrading air quality, reducing visibility, transporting pathogens, and inducing respiratory problems. The atmospheric radiative forcing by the <span class="hlt">dust</span> has implications for global climate change and presently is one of the largest unknowns in climate models. These uncertainties have <span class="hlt">lead</span> to much of the funding for research into the sources, properties, and fate of atmospheric <span class="hlt">dust</span>. As a result of advances in numerical weather prediction over the past decades and the recent climate research, we are now in a position to produce operational <span class="hlt">dust</span> storm forecasts. International organizations and national agencies are developing programs for <span class="hlt">dust</span> forecasting. The approaches and applications of <span class="hlt">dust</span> detection and forecasting are as varied as the nations that are developing the models. The basic components of a <span class="hlt">dust</span> forecasting system include atmospheric forcing, <span class="hlt">dust</span> production, and <span class="hlt">dust</span> microphysics. The forecasting applications include air and auto traffic safety, shipping, health, national security, climate and weather. This presentation will summarize the methods of <span class="hlt">dust</span> storm forecasting and illustrate the various applications. The major remaining uncertainties (e.g. sources and initialization) will be discussed as well as approaches for solving those problems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930092096','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930092096"><span>Formulas for the Supersonic <span class="hlt">Loading</span>, Lift, and Drag of Flat Swept-Back Wings with <span class="hlt">Leading</span> Edges Behind the Mach Line</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cohen, Doris</p> <p>1951-01-01</p> <p>The method of superposition of linearized conical flows has been applied to the calculation of the aerodynamic properties, in supersonic flight, of thin flat, swept-back wings at an angle of attack. The wings are assumed to have rectilinear plan forms, with tips parallel to the stream, and to taper in the conventional sense. The investigation covers the moderately supersonic speed range where the Mach lines from the <span class="hlt">leading</span>-edge apex lie ahead of the wing. The trailing edge may lie ahead of or behind the Mach lines from its apex. The case in which the Mach cone from one tip intersects the other tip is not treated. Formulas are obtained for the <span class="hlt">load</span> distribution, the total lift, and the drag due to lift. For the cases in which the trailing edge is outside the Mach cone from its apex the formulas are complete. For wings with both <span class="hlt">leading</span> and trailing edges behind their respective Mach lines, a degree of approximation is necessary. Charts of some of the functions derived are included to facilitate computing, and several examples are worked out in outline.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19349381','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19349381"><span>Health risks due to coffee <span class="hlt">dust</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Oldenburg, Marcus; Bittner, Cordula; Baur, Xaver</p> <p>2009-08-01</p> <p>This study assessed current health risks due to occupational exposure to coffee <span class="hlt">dust</span>. We performed a cross-sectional study in a coffee haulage company (n = 24), a coffee silo (n = 19), and a decaffeinating company (n = 17). Cross-shift and cross-week case histories of these employees as well as lung function values were recorded. During the handling of green coffee, measurements of airborne <span class="hlt">dust</span> were conducted. The employees in these workplaces were mainly affected by erythematous and rhinoconjunctival symptoms. They occurred especially in subjects exposed to a high <span class="hlt">dust</span> <span class="hlt">load</span> (> 10 mg of inhalable <span class="hlt">dust</span> per cubic meter of air; n = 28) [Pearson chi(2) test, p = 0.020 and p = 0.023]. IgE antibodies to green coffee and castor beans were detected in 3 workers and 10 workers, respectively. The majority of them (two employees and six employees, respectively) had shown respiratory symptoms during the past 12 months. The preshift lung function values were below average but were not dependent on the level of the inhalable coffee <span class="hlt">dust</span> exposure. Employees with a coffee <span class="hlt">dust</span> <span class="hlt">load</span> > 10 mg/m(3) of air showed higher unspecific bronchial responsiveness more frequently than those with lower exposures. During the transshipment (especially during unloading) of green coffee, a high and clinically relevant exposure to irritative and sensitizing <span class="hlt">dust</span> occurs. Therefore, efforts to reduce these <span class="hlt">dust</span> exposures are generally recommended.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4886520','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4886520"><span>Sampling and analysis method for measuring airborne coal <span class="hlt">dust</span> mass in mixtures with limestone (rock) <span class="hlt">dust</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Barone, T. L.; Patts, J. R.; Janisko, S. J.; Colinet, J. F.; Patts, L. D.; Beck, T. W.; Mischler, S. E.</p> <p>2016-01-01</p> <p>Airborne coal <span class="hlt">dust</span> mass measurements in underground bituminous coal mines can be challenged by the presence of airborne limestone <span class="hlt">dust</span>, which is an incombustible <span class="hlt">dust</span> applied to prevent the propagation of <span class="hlt">dust</span> explosions. To accurately measure the coal portion of this mixed airborne <span class="hlt">dust</span>, 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 <span class="hlt">dust</span> 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 <span class="hlt">dust</span> samples. Mixtures of known coal and limestone <span class="hlt">dust</span> masses were prepared in the laboratory, <span class="hlt">loaded</span> into the stainless steel cassettes, and analyzed to assess the accuracy of this method. Coal <span class="hlt">dust</span> 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 <span class="hlt">dust</span>, 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 <span class="hlt">dust</span> samples collected in an underground coal mine. PMID:26618374</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26618374','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26618374"><span>Sampling and analysis method for measuring airborne coal <span class="hlt">dust</span> mass in mixtures with limestone (rock) <span class="hlt">dust</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Barone, T L; Patts, J R; Janisko, S J; Colinet, J F; Patts, L D; Beck, T W; Mischler, S E</p> <p>2016-01-01</p> <p>Airborne coal <span class="hlt">dust</span> mass measurements in underground bituminous coal mines can be challenged by the presence of airborne limestone <span class="hlt">dust</span>, which is an incombustible <span class="hlt">dust</span> applied to prevent the propagation of <span class="hlt">dust</span> explosions. To accurately measure the coal portion of this mixed airborne <span class="hlt">dust</span>, 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 <span class="hlt">dust</span> 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 <span class="hlt">dust</span> samples. Mixtures of known coal and limestone <span class="hlt">dust</span> masses were prepared in the laboratory, <span class="hlt">loaded</span> into the stainless steel cassettes, and analyzed to assess the accuracy of this method. Coal <span class="hlt">dust</span> 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 <span class="hlt">dust</span>, 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 <span class="hlt">dust</span> samples collected in an underground coal mine.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AtmEn..70..245M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AtmEn..70..245M"><span>Assessments for the impact of mineral <span class="hlt">dust</span> on the meningitis incidence in West Africa</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Martiny, Nadège; Chiapello, Isabelle</p> <p>2013-05-01</p> <p>Recently, mineral <span class="hlt">dust</span> has been suspected to be one of the important environmental risk factor for meningitis epidemics in West Africa. The current study is one of the first which relies on long-term robust aerosol measurements in the Sahel region to investigate the possible impact of mineral <span class="hlt">dust</span> on meningitis cases (incidence). Sunphotometer measurements, which allow to derive aerosol and humidity parameters, i.e., aerosol optical thickness, Angström coefficient, and precipitable water, are combined with quantitative epidemiological data in Niger and Mali over the 2004-2009 AMMA (African Monsoon Multidisciplinary Analysis) program period. We analyse how the extremely high aerosol <span class="hlt">loads</span> in this region may influence both the calendar (onset, peaks, end) and the intensity of meningitis. We highlight three distinct periods: (i) from November to December, beginning of the dry season, humidity is weak, there is no <span class="hlt">dust</span> and no meningitis cases; (ii) from January to April, humidity is still weak, but high <span class="hlt">dust</span> <span class="hlt">loads</span> occur in the atmosphere and this is the meningitis season; (iii) from May to October, humidity is high and there is no meningitis anymore, in presence of <span class="hlt">dust</span> or not, which flow anyway in higher altitudes. More specifically, the onset of the meningitis season is tightly related to mineral <span class="hlt">dust</span> flowing close to the surface at the very beginning of the year. During the dry, and the most dusty season period, from February to April, each meningitis peak is preceded by a <span class="hlt">dust</span> peak, with a 0-2 week <span class="hlt">lead</span>-time. The importance (duration, intensity) of these meningitis peaks seems to be related to that of <span class="hlt">dust</span>, suggesting that a cumulative effect in <span class="hlt">dust</span> events may be important for the meningitis incidence. This is not the case for humidity, confirming the special contribution of <span class="hlt">dust</span> at this period of the year. The end of the meningitis season, in May, coincides with a change in humidity conditions related to the West African Monsoon. These results, which are</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23250385','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23250385"><span>Muzzle-<span class="hlt">loading</span> weapons discharging spherical <span class="hlt">lead</span> bullets: two case studies and experimental simulation using a skin-soap composite model.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Große Perdekamp, Markus; Braunwarth, Roland; Kromeier, Jan; Nadjem, Hadi; Pollak, Stefan; Thierauf, Annette</p> <p>2013-07-01</p> <p>In current forensic practice, fatal injuries from black powder guns are rare events. In contact and close-range shots, the intensity of GSR deposition (soot, powder particles) is much greater than that in shots with smokeless powder ammunition. The same applies to any burning effects from the combustion gases. Besides, a wad of felt interposed between the propellant and the <span class="hlt">lead</span> bullet may enter the wound channel. Apart from these findings seen in close-range shots, another characteristic feature results from the mostly spherical shape of the missiles causing maximum tissue damage at the entrance site. Two fatal injuries inflicted with muzzle-<span class="hlt">loading</span> weapons are reported. In the first case, suicide was committed with a cal. 11.6 mm miniature cannon by firing a contact shot to the back of the neck. In test shots using black powder (1 and 2 g) as propellant, the mean bullet velocity measured 1 m away from the weapon was 87.11 and 146.85 m/s, respectively, corresponding to a kinetic energy of 32.49 and 92.95 J, respectively. Contact test shots to composite models consisting of ballistic soap covered by pig skin at the entrance site were evaluated by CT and revealed cone-like cavitations along the bullet path as known from spherical missiles and penetration depths up to 25 cm. The second case presented deals with a homicidal close-range shot discharged from a muzzle-<span class="hlt">loading</span> percussion pistol cal. .44. The skin around the entrance site (root of the nose) was densely covered with blackish soot and powder particles, whereas the eyebrows and eyelashes showed singeing of the hairs. The flattened bullet and the wad had got stuck under the scalp of the occipital region. In both cases, there was a disproportionally large zone of tissue destruction in the initial parts of the wound tracks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AtmEn..38.4895Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AtmEn..38.4895Q"><span>Regional characteristics of <span class="hlt">dust</span> storms in China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Qian, Weihong; Tang, Xu; Quan, Linsheng</p> <p>2004-09-01</p> <p>Regional characteristics of <span class="hlt">dust</span> storms in northern China are analyzed using a rotated empirical orthogonal function (REOF), based on the annual days of <span class="hlt">dust</span> storms from 1954 to 1998. The relationships between regional <span class="hlt">dust</span> storms corresponding to other factors such as precipitation and temperature are explored. The results show that five <span class="hlt">leading</span> modes of <span class="hlt">dust</span> storms exist in the following areas: the Taklamakan Desert (Tarim Basin) over the Xinjiang region (far northwestern China), the eastern part of Inner Mongolia (North China), the Tsaidam Basin, the Tibetan Plateau, and the upper reaches of the Yellow River (Gobi Desert). These areas are associated with an arid climate and frequent winds. For the first mode in the Tarim Basin, most <span class="hlt">dust</span> storms appear in the 1980s, while <span class="hlt">dust</span> storms become less frequent in the 1990s. The second mode (North China) shows the highest frequency of <span class="hlt">dust</span> storms in the mid-1960s but the frequency decreases afterward. The third mode indicates a decreasing trend of annual <span class="hlt">dust</span> storms after the mid-1960s but with a high interannual variability. The fourth mode also shows a decreasing trend but with a low interannual variability. The fifth mode displays a high frequency of <span class="hlt">dust</span> storms in the 1970s followed by a decreasing trend. For the five modes of <span class="hlt">dust</span> storm distribution, four of the centers are located in desert regions. The annual <span class="hlt">dust</span> storms of a selected station in each mode region are shown to compare the coefficient time series of these modes. The negative correlation between the prior winter temperature and <span class="hlt">dust</span> storm frequency is identified for most stations. There is no consistency in the correlation between the <span class="hlt">dust</span> storm frequency and the annual rainfall as well as the prior winter rainfall at these stations. The activity of <span class="hlt">dust</span> storms in northern China are directly linked to the cyclone activity, especially for the interdecadal variability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://medlineplus.gov/ency/patientinstructions/000487.htm','NIH-MEDLINEPLUS'); return false;" href="https://medlineplus.gov/ency/patientinstructions/000487.htm"><span>Allergies, asthma, and <span class="hlt">dust</span></span></a></p> <p><a target="_blank" href="http://medlineplus.gov/">MedlinePlus</a></p> <p></p> <p></p> <p>... help control <span class="hlt">dust</span>. The system should include special filters to capture <span class="hlt">dust</span> and animal dander. Change furnace filters frequently. Use high efficiency particulate air (HEPA) filters. When cleaning: Wipe away <span class="hlt">dust</span> with a damp cloth and vacuum once a ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.A53D0214P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.A53D0214P"><span>Saharan Mineral <span class="hlt">Dust</span> Experiment SAMUM 2006: Airborne observations of <span class="hlt">dust</span> particle properties and vertical <span class="hlt">dust</span> profiles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Petzold, A.; Weinzierl, B.; Esselborn, M.; Fiebig, M.; Fix, A.; Kiemle, C.; Wirth, M.; Müller, D.; Wendisch, M.; Schuetz, L.; Kandler, K.; Kahn, R.; Wagner, F.; Pereira, S.; Virkkula, A.</p> <p>2006-12-01</p> <p> during the long-range transport events. First results will be presented on <span class="hlt">dust</span> size distributions in several altitudes, <span class="hlt">dust</span> optical properties and aerosol optical depths determined from HSRL and aerosol size distribution data. Vertical profiles of the <span class="hlt">dust</span> mass <span class="hlt">loading</span> will be discussed for the field sites of Zagora at the Saharan border and Evora in Portugal from the combination of ground-based and airborne measurements. This work is supported by the Deutsche Forschungsgemeinschaft DFG, the European Space Agency ESA and the European Fleet for Airborne research EUFAR.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-GSFC_20170927_Archive_e001041.jpg.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-GSFC_20170927_Archive_e001041.jpg.html"><span>Saharan <span class="hlt">Dust</span> on the Move</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2017-09-27</p> <p>A piece of Africa—actually lots of them—began to arrive in the Americas in June 2014. On June 23, a lengthy river of <span class="hlt">dust</span> from western Africa began to push across the Atlantic Ocean on easterly winds. A week later, the influx of <span class="hlt">dust</span> was affecting air quality as far away as the southeastern United States. This composite image, made with data from the Visible Infrared Imaging Radiometer Suite (VIIRS) on Suomi NPP, shows <span class="hlt">dust</span> heading west toward South America and the Gulf of Mexico on June 25, 2014. The <span class="hlt">dust</span> flowed roughly parallel to a line of clouds in the intertropical convergence zone, an area near the equator where the trade winds come together and rain and clouds are common. In imagery captured by the Moderate Resolution Imaging Spectroradiometer (MODIS), the <span class="hlt">dust</span> appeared to be streaming from Mauritania, Senegal, and Western Sahara, though some of it may have originated in countries farther to the east. Saharan <span class="hlt">dust</span> has a range of impacts on ecosystems downwind. Each year, <span class="hlt">dust</span> events like the one pictured here deliver about 40 million tons of <span class="hlt">dust</span> from the Sahara to the Amazon River Basin. The minerals in the <span class="hlt">dust</span> replenish nutrients in rainforest soils, which are continually depleted by drenching, tropical rains. Research focused on peat soils in the Everglades show that African <span class="hlt">dust</span> has been arriving regularly in South Florida for thousands of years as well. In some instances, the impacts are harmful. Infusion of Saharan <span class="hlt">dust</span>, for instance, can have a negative impact on air quality in the Americas. And scientists have linked African <span class="hlt">dust</span> to outbreaks of certain types of toxic algal blooms in the Gulf of Mexico and southern Florida. Read more: 1.usa.gov/1snkzmS NASA images by Norman Kuring, NASA’s Ocean Color web. Caption by Adam Voiland. Credit: NASA Earth Observatory NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19840015421&hterms=filter+dust&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dfilter%2Bdust','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19840015421&hterms=filter+dust&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dfilter%2Bdust"><span><span class="hlt">Dust</span> streaks on Mars: Colors and photometry</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Thomas, P.</p> <p>1984-01-01</p> <p>Photometric studies of crater related bright and dark streaks have strongly supported the hypothesis that the bright streaks are excess <span class="hlt">dust</span> deposits and dark streaks are erosional windows in a partial <span class="hlt">dust</span> cover. Red-blue (and red-violet) plots show that bright streaks are consistent with mosaics of bright red <span class="hlt">dust</span> and background material. Here the plains are also consistent with a partial <span class="hlt">dust</span> cover; the dark streak is the least covered area. Bright and dark streaks both reverse contrast relative to surrounding plains at phase angles over 100 deg in violet filter images. The similar phase behavior of both bright and dark streaks supports the idea that they are both changes in the amount of <span class="hlt">dust</span> cover. Red-violet plots of bright streaks are most easily explained by mosaics of optically thick <span class="hlt">dust</span> and plains material. Lengths of bright streaks are independent of their contrasts. This suggests the streak deposition, if in the mosaic patterns indicated above, is a function of available sites of deposition, rather than atmospheric <span class="hlt">dust</span> <span class="hlt">loading</span>. Contrasts of dark streaks with plains indicate the plains have fractional <span class="hlt">dust</span> covers nealy as great as the maximum additional cover in bright streaks. The bright streaks thus store little of the global supply of <span class="hlt">dust</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=MSFC-0101734&hterms=flour&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dflour','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=MSFC-0101734&hterms=flour&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dflour"><span><span class="hlt">Dust</span> agglomeration</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2000-01-01</p> <p>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 <span class="hlt">dust</span> clouds that form planets to tiny compressed pellets, such as the ones you swallow as tablets. This knowledge should help us control the grains, <span class="hlt">dust</span>, 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.)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=MSFC-0101734&hterms=granules&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dgranules','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=MSFC-0101734&hterms=granules&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dgranules"><span><span class="hlt">Dust</span> agglomeration</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2000-01-01</p> <p>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 <span class="hlt">dust</span> clouds that form planets to tiny compressed pellets, such as the ones you swallow as tablets. This knowledge should help us control the grains, <span class="hlt">dust</span>, 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.)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMPP13D..03L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMPP13D..03L"><span>Reconstruction of global atmospheric <span class="hlt">dust</span> concentrations using <span class="hlt">dust</span> flux measurements in paleoclimatic archives and <span class="hlt">dust</span> model variables</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lambert, F.; Rojas, M.; Gallardo, L.; Mahowald, N. M.; Takemura, T.; KUG, J.; Winckler, G.; Park, R.; Abe-Ouchi, A.</p> <p>2013-12-01</p> <p>Aerosols are the second most potent agent affecting anthropogenic radiative forcing after greenhouse gases. However, despite some progress in the field, the uncertainty of aerosol impact on present and past climate remains much larger than for other species. The total atmospheric <span class="hlt">dust</span> <span class="hlt">load</span> is an important factor for the radiative budget of the atmosphere, and for the micronutrient supply to terrestrial and marine ecosystems. We have collected published <span class="hlt">dust</span> flux (mass accumulation rate) measurements from marine sediment cores, ice cores, loess fields, and peat bogs. These measurements are interpolated to two global grids of average Holocene and Last Glacial Maximum (LGM) climatic conditions. The interpolation is performed using a kriging algorithm and its uncertainty shows regions where new measurements are most needed. We have developed a new method that combines observational <span class="hlt">dust</span> flux measurements with <span class="hlt">dust</span> depositional variables from climate models to reconstruct average Holocene and LGM atmospheric <span class="hlt">dust</span> concentrations. Here we use <span class="hlt">dust</span> simulations from two different coupled GCMs (CAM3-CCSM3 and SPRINTARS-MIROC) to give an idea of the uncertainties due to model variables. Our reconstructions give a different perspective on Holocene and LGM atmospheric <span class="hlt">dust</span> <span class="hlt">loads</span> from pure model simulations. The discrepancies between modeled and reconstructed <span class="hlt">dust</span> concentrations and radiative forcing gives insights on regions and variables that may be improved in the models. In addition, this method allows to follow the temporal and spatial evolution of <span class="hlt">dust</span> <span class="hlt">loads</span> (and the resulting changes in radiative forcing and iron fertilization) through the glacial-interglacial transition. Top row: Interpolated Mass Accumulation Rates (MAR) for average Holocene (left column) and Last Glacial Maximum (right column) climatic conditions. The second and third row show simulated MAR from two different coupled climate models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19910005584','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19910005584"><span>Interstellar <span class="hlt">Dust</span>: Contributed Papers</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tielens, Alexander G. G. M. (Editor); Allamandola, Louis J. (Editor)</p> <p>1989-01-01</p> <p>A coherent picture of the <span class="hlt">dust</span> composition and its physical characteristics in the various phases of the interstellar medium was the central theme. Topics addressed included: <span class="hlt">dust</span> in diffuse interstellar medium; overidentified infrared emission features; <span class="hlt">dust</span> in dense clouds; <span class="hlt">dust</span> in galaxies; optical properties of <span class="hlt">dust</span> grains; interstellar <span class="hlt">dust</span> models; interstellar <span class="hlt">dust</span> and the solar system; <span class="hlt">dust</span> formation and destruction; UV, visible, and IR observations of interstellar extinction; and quantum-statistical calculations of IR emission from highly vibrationally excited polycyclic aromatic hydrocarbon (PAH) molecules.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SPIE.9876E..2SS','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SPIE.9876E..2SS"><span><span class="hlt">Dust</span> storm events over Delhi: verification of <span class="hlt">dust</span> AOD forecasts with satellite and surface observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Singh, Aditi; Iyengar, Gopal R.; George, John P.</p> <p>2016-05-01</p> <p>Thar desert located in northwest part of India is considered as one of the major <span class="hlt">dust</span> source. <span class="hlt">Dust</span> storms originate in Thar desert during pre-monsoon season, affects large part of Indo-Gangetic plains. High <span class="hlt">dust</span> <span class="hlt">loading</span> causes the deterioration of the ambient air quality and degradation in visibility. Present study focuses on the identification of <span class="hlt">dust</span> events and verification of the forecast of <span class="hlt">dust</span> events over Delhi and western part of IG Plains, during the pre-monsoon season of 2015. Three <span class="hlt">dust</span> events have been identified over Delhi during the study period. For all the selected days, Terra-MODIS AOD at 550 nm are found close to 1.0, while AURA-OMI AI shows high values. <span class="hlt">Dust</span> AOD forecasts from NCMRWF Unified Model (NCUM) for the three selected <span class="hlt">dust</span> events are verified against satellite (MODIS) and ground based observations (AERONET). Comparison of observed AODs at 550 nm from MODIS with NCUM predicted AODs reveals that NCUM is able to predict the spatial and temporal distribution of <span class="hlt">dust</span> AOD, in these cases. Good correlation (~0.67) is obtained between the NCUM predicted <span class="hlt">dust</span> AODs and location specific observations available from AERONET. Model under-predicted the AODs as compared to the AERONET observations. This may be mainly because the model account for only <span class="hlt">dust</span> and no anthropogenic activities are considered. The results of the present study emphasize the requirement of more realistic representation of local <span class="hlt">dust</span> emission in the model both of natural and anthropogenic origin, to improve the forecast of <span class="hlt">dust</span> from NCUM during the <span class="hlt">dust</span> events.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMPP33D..07P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMPP33D..07P"><span>The Mid-Holocene West African Monsoon strength modulated by Saharan <span class="hlt">dust</span> and vegetation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pausata, F. S. R.; Messori, G.; Zhang, Q.</p> <p>2015-12-01</p> <p>The West African Monsoon (WAM) is crucial for the socio-economic stability of millions of people living in the Sahel. Severe droughts have ravaged the region in the last three decades of the 20th century, highlighting the need for a better understanding of the WAM dynamics. One of the most dramatic changes in the WAM occurred between 15,000-5,000 years BP, when increased summer precipitation led to the so-called "Green Sahara" and to a reduction in <span class="hlt">dust</span> emissions from the region. Previous studies have shown that variations in vegetation and soil type can have major impacts on precipitation. However, model simulations are still unable to fully reproduce the intensification and geographical expansion of the African monsoon during that period, even when vegetation over the Sahara is simulated. Here, we use a fully coupled simulation for 6000 years BP in which prescribed Saharan vegetation and <span class="hlt">dust</span> concentrations are changed in turn. A close agreement with proxy records is obtained only when both Saharan vegetation and <span class="hlt">dust</span> decrease are taken into account (Fig. 1). The <span class="hlt">dust</span> reduction extends the monsoon's northern limit further than the vegetation-change case only (Fig. 2), by strengthening vegetation-albedo feedbacks and driving a deeper Saharan Heat Low. The <span class="hlt">dust</span> reduction under vegetated Sahara conditions <span class="hlt">leads</span> to a northward shift of the WAM extension that is about twice as large as the shift due to the changes in orbital forcing alone. We therefore conclude that accounting for changes in Saharan <span class="hlt">dust</span> <span class="hlt">loadings</span> is essential for improving model simulations of the MH WAM. The role of <span class="hlt">dust</span> is also relevant when looking into the future, since Saharan <span class="hlt">dust</span> emission may decrease owing to both direct and indirect anthropogenic impacts on land cover.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17386450','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17386450"><span>Biosorption of copper(II), <span class="hlt">lead</span>(II), iron(III) and cobalt(II) on Bacillus sphaericus-<span class="hlt">loaded</span> Diaion SP-850 resin.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tuzen, Mustafa; Uluozlu, Ozgur Dogan; Usta, Canan; Soylak, Mustafa</p> <p>2007-01-09</p> <p>The biosorption of copper(II), <span class="hlt">lead</span>(II), iron(III) and cobalt(II) on Bacillus sphaericus-<span class="hlt">loaded</span> Diaion SP-850 resin for preconcentration-separation of them have been investigated. The sorbed analytes on biosorbent were eluted by using 1 mol L(-1) HCl and analytes were determined by flame atomic absorption spectrometry. The influences of analytical parameters including amounts of pH, B. sphaericus, sample volume etc. on the quantitative recoveries of analytes were investigated. The effects of alkaline, earth alkaline ions and some metal ions on the retentions of the analytes on the biosorbent were also examined. Separation and preconcentration of Cu, Pb, Fe and Co ions from real samples was achieved quantitatively. The detection limits by 3 sigma for analyte ions were in the range of 0.20-0.75 microg L(-1) for aqueous samples and in the range of 2.5-9.4 ng g(-1) for solid samples. The validation of the procedure was performed by the analysis of the certified standard reference materials (NRCC-SLRS 4 Riverine Water, SRM 2711 Montana soil and GBW 07605 Tea). The presented method was applied to the determination of analyte ions in green tea, black tea, cultivated mushroom, boiled wheat, rice and soil samples with successfully results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/352594','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/352594"><span>Metal <span class="hlt">dusting</span> of nickel-containing alloys</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Baker, B.A.; Smith, G.D.</p> <p>1998-12-31</p> <p>Metal <span class="hlt">dusting</span> is a catastrophic form of carburization which <span class="hlt">leads</span> to pitting and grooves as the affected metal disintegrates into a mixture of powdery carbon, metallic particles, and possibly oxides and carbides. This high temperature carburization mode is not yet well understood and while relatively infrequent, can be economically disastrous when it does occur in large and complex chemical and petrochemical process streams. References in the literature show that all classes of heat resistant alloys are prone to metal <span class="hlt">dusting</span>, given the necessary and specific environmental conditions. These same references describe the environments that plague nickel-containing alloys and are used as the basis for postulation on the probable corrosion mechanisms responsible for metal <span class="hlt">dusting</span>. Using alloy 800 and other nickel-containing alloys and metal <span class="hlt">dusting</span> atmospheres, an effort is made to examine the steps in the metal <span class="hlt">dusting</span> process and the temperature ranges over which metal <span class="hlt">dusting</span> occurs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006ERL.....1a1001R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006ERL.....1a1001R"><span>PERSPECTIVE: <span class="hlt">Dust</span>, fertilization and sources</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Remer, Lorraine A.</p> <p>2006-11-01</p> <p>Aerosols, tiny suspended particles in the atmosphere, play an important role in modifying the Earth's energy balance and are essential for the formation of cloud droplets. Suspended <span class="hlt">dust</span> particles lifted from the world's arid regions by strong winds contain essential minerals that can be transported great distances and deposited into the ocean or on other continents where productivity is limited by lack of usable minerals [1]. <span class="hlt">Dust</span> can transport pathogens as well as minerals great distance, contributing to the spread of human and agricultural diseases, and a portion of <span class="hlt">dust</span> can be attributed to human activity suggesting that <span class="hlt">dust</span> radiative effects should be included in estimates of anthropogenic climate forcing. The greenish and brownish tints in figure 1 show the wide extent of monthly mean mineral <span class="hlt">dust</span> transport, as viewed by the MODerate resolution Imaging Spectroradiometer (MODIS) satellite sensor. The monthly mean global aerosol system for February 2006 from the MODIS aboard the Terra satellite Figure 1. The monthly mean global aerosol system for February 2006 from the MODIS aboard the Terra satellite. The brighter the color, the greater the aerosol <span class="hlt">loading</span>. Red and reddish tints indicate aerosol dominated by small particles created primarily from combustion processes. Green and brownish tints indicate larger particles created from wind-driven processes, usually transported desert <span class="hlt">dust</span>. Note the bright green band at the southern edge of the Saharan desert, the reddish band it must cross if transported to the southwest and the long brownish transport path as it crosses the Atlantic to South America. Image courtesy of the NASA Earth Observatory (http://earthobservatory.nasa.gov). Even though qualitatively we recognize the extent and importance of <span class="hlt">dust</span> transport and the role that it plays in fertilizing nutrient-limited regions, there is much that is still unknown. We are just now beginning to quantify the amount of <span class="hlt">dust</span> that exits one continental region and the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004JGRD..10919S21T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004JGRD..10919S21T"><span>Impacts of <span class="hlt">dust</span> on regional tropospheric chemistry during the ACE-Asia experiment: A model study with observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tang, Youhua; Carmichael, Gregory R.; Kurata, Gakuji; Uno, Itsushi; Weber, Rodney J.; Song, Chul-Han; Guttikunda, Sarath K.; Woo, Jung-Hun; Streets, David G.; Wei, Cao; Clarke, Antony D.; Huebert, Barry; Anderson, Theodore L.</p> <p>2004-10-01</p> <p>A comprehensive regional-scale chemical transport model, Sulfur Transport and Emissions Model 2001 (STEM-2K1), is employed to study <span class="hlt">dust</span> outflows and their influence on regional chemistry in the high-<span class="hlt">dust</span> Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia) period, from 4-14 April 2001. In this period, <span class="hlt">dust</span> storms are initialized in the Taklamagan and Gobi deserts because of cold air outbreaks, are transported eastward, and are often intensified by <span class="hlt">dust</span> emitted from exposed soils as the front moves off the continent. Simulated <span class="hlt">dust</span> agrees well with surface weather observations, satellite images, and the measurements of the C-130 aircraft. The C-130 aircraft observations of chemical constituents of the aerosol are analyzed for <span class="hlt">dust</span>-rich and low-<span class="hlt">dust</span> periods. In the submicron aerosol, <span class="hlt">dust</span>-rich air masses have elevated ratios of ΔCa/ΔMg, ΔNH4+/ΔSO42-, and ΔNO3-/ΔCO (Δ represents the difference between observed and background concentrations). The impacts of heterogeneous reactions on <span class="hlt">dust</span> involving O3, NO2, SO2, and HNO3 are studied by incorporating these reactions into the analysis. These reactions have significant influence on regional chemistry. For example, the low O3 concentrations in C-130 flight 6 can be explained only by the influence of heterogeneous reactions. In the near-surface layer, the modeled heterogeneous reactions indicated that O3, SO2, NO2, and HNO3 are decreased by up to 20%, 55%, 20%, and 95%, respectively, when averaged over this period. In addition, NO, HONO, and daytime OH can increase by 20%, 30%, and 4%, respectively, over polluted regions. When <span class="hlt">dust</span> encounters fresh pollutants, these heterogeneous reactions can <span class="hlt">lead</span> to a series of complex responses of the photochemical system. In addition, these reactions can alter the chemical-size distribution of the aerosol. Under heavy <span class="hlt">dust</span> <span class="hlt">loadings</span>, these reactions can <span class="hlt">lead</span> to >20% of the sulfate and >70% of the nitrate being associated with the coarse fraction. The radiative</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17194531','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17194531"><span><span class="hlt">Dust</span> explosions-cases, causes, consequences, and control.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Abbasi, Tasneem; Abbasi, S A</p> <p>2007-02-09</p> <p><span class="hlt">Dust</span> explosions pose the most serious and widespread of explosion hazards in the process industry alongside vapour cloud explosions (VCE) and boiling liquid expanding vapour explosions (BLEVE). <span class="hlt">Dust</span> explosions almost always <span class="hlt">lead</span> to serious financial losses in terms of damage to facilities and down time. They also often cause serious injuries to personnel, and fatalities. We present the gist of the <span class="hlt">dust</span> explosion state-of-the-art. Illustrative case studies and past accident analyses reflect the high frequency, geographic spread, and damage potential of <span class="hlt">dust</span> explosions across the world. The sources and triggers of <span class="hlt">dust</span> explosions, and the measures with which different factors associated with <span class="hlt">dust</span> explosions can be quantified are reviewed alongside <span class="hlt">dust</span> explosion mechanism. The rest of the review is focused on the ways available to prevent <span class="hlt">dust</span> explosion, and on cushioning the impact of a <span class="hlt">dust</span> explosion by venting when the accident does take place.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ChPhB..25i5202Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ChPhB..25i5202Y"><span>Formation and dissociation of <span class="hlt">dust</span> molecules in dusty plasma</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yan, Jia; Feng, Fan; Liu, Fucheng; Dong, Lifang; He, Yafeng</p> <p>2016-09-01</p> <p><span class="hlt">Dust</span> molecules are observed in a dusty plasma experiment. By using measurements with high spatial resolution, the formation and dissociation of the <span class="hlt">dust</span> molecules are studied. The ion cloud in the wake of an upper <span class="hlt">dust</span> grain attracts the lower <span class="hlt">dust</span> grain nearby. When the interparticle distance between the upper <span class="hlt">dust</span> grain and the lower one is less than a critical value, the two <span class="hlt">dust</span> grains would form a <span class="hlt">dust</span> molecule. The upper <span class="hlt">dust</span> grain always <span class="hlt">leads</span> the lower one as they travel. When the interparticle distance between them is larger than the critical value, the <span class="hlt">dust</span> molecule would dissociate. Project supported by the National Natural Science Foundation of China (Grant Nos. 11205044 and 11405042), the Natural Science Foundation of Hebei Province, China (Grant Nos. A2011201006 and A2012201015), the Research Foundation of Education Bureau of Hebei Province, China (Grant No. Y2012009), the Program for Young Principal Investigators of Hebei Province, China, and the Midwest Universities Comprehensive Strength Promotion Project, China.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090004550','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090004550"><span>Lunar <span class="hlt">Dust</span> 101</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gaier, James R.</p> <p>2008-01-01</p> <p>Largely due to rock and soil samples returned during the Apollo program, much has been learned about the composition and properties of lunar regolith. Although, for the most part, the mineral composition resembles terrestrial minerals, the characteristics of the lunar environment have led to very different weathering processes. These result in substantial differences in the particle shapes, particle size distributions, and surface chemistry. These differences <span class="hlt">lead</span> to non-intuitive adhesion, abrasion, and possible health properties that will pose challenges to future lunar missions. An overview of lunar <span class="hlt">dust</span> composition and properties will be given with a particular emphasis on possible health effects.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JASTP.150...55L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JASTP.150...55L"><span>Point discharge current measurements beneath <span class="hlt">dust</span> devils</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lorenz, Ralph D.; Neakrase, Lynn D. V.; Anderson, John P.; Harrison, R. Giles; Nicoll, Keri A.</p> <p>2016-12-01</p> <p>We document for the first time observations of point discharge currents under <span class="hlt">dust</span> devils using a novel compact sensor deployed in summer 2016 at the USDA-ARS Jornada Experimental Range in New Mexico, USA. A consistent signature is noted in about a dozen events seen over 40 days, with a positive current ramping up towards closest approach, switching to a decaying negative current as the devil recedes. The currents, induced on a small wire about 10 cm above the ground, correlate with <span class="hlt">dust</span> devil intensity (pressure drop) and <span class="hlt">dust</span> <span class="hlt">loading</span>, and reached several hundred picoAmps.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=181927&keyword=voltammetry&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=89221594&CFTOKEN=81967585','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=181927&keyword=voltammetry&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=89221594&CFTOKEN=81967585"><span>PORTABLE TECHNOLOGIES FOR MEASURING <span class="hlt">LEADING</span> IN <span class="hlt">DUST</span></span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>The U.S. Environmental Protection Agency (EPA) Environmental Technology Verification (ETV) program evaluates the performance of innovative air, water, pollution prevention and monitoring technologies that have the potential to improve human health and the environment. This techn...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=181927&keyword=tb&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=181927&keyword=tb&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>PORTABLE TECHNOLOGIES FOR MEASURING <span class="hlt">LEADING</span> IN <span class="hlt">DUST</span></span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>The U.S. Environmental Protection Agency (EPA) Environmental Technology Verification (ETV) program evaluates the performance of innovative air, water, pollution prevention and monitoring technologies that have the potential to improve human health and the environment. This techn...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.7426F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.7426F"><span>Characterization of alluvial <span class="hlt">dust</span> sources and their temporal development - a multi-sensor approach for the Aïr Massif, Niger</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Feuerstein, Stefanie; Schepanski, Kerstin</p> <p>2017-04-01</p> <p>One of the world's largest sources of atmospheric <span class="hlt">dust</span> is the Sahara. It is said that 55% of the total global <span class="hlt">dust</span> emission can be linked to the desert in northern Africa. Thus, understanding the Saharan <span class="hlt">dust</span> sources is of great importance to estimate the total global <span class="hlt">dust</span> <span class="hlt">load</span> and its variability. Especially one type of <span class="hlt">dust</span> sources has gained attention in <span class="hlt">dust</span> research in recent years: The emission of <span class="hlt">dust</span> from sediments formed by hydrologic processes, so called alluvial <span class="hlt">dust</span> sources. These sediments were either formed in the past under the influences of a more humid paleoclimate or are deposited recently, e.g. during strong precipitation events when surficial runoff <span class="hlt">leads</span> to the activation of wadi systems or to the occurrence of flash floods. Especially the latter phenomenon is able to deliver a huge amount of potentially erodible sediments. The research presented here focuses on the characterization of these alluvial <span class="hlt">dust</span> sources with special attention on their temporal variability in relation to wet and dry phases. A study area covering the Aïr Massif in Niger is analysed over a four years time span from January 2013 to December 2016. The whole cycle from sediment formation to <span class="hlt">dust</span> emission is illustrated by using data of various satellite sensors that are able to capture the processes taking place at the land surface as well as in the atmosphere: (1) The rainfall distribution for the study area is shown by time series of the TRMM precipitation estimates. A catchment analysis of the area helps to estimate the amount of surficial runoff and to detect areas of potential sediment accumulation. (2) Changes in the sediment structure of the land surface are analysed using atmospherically corrected time series of NASA's Landsat-8 OLI satellite. A land cover classification shows the distribution of alluvial sediments over the area; fresh layers of alluvial deposits are detected. Furthermore, the evolution of the vegetation cover, which inhibits <span class="hlt">dust</span> emission, is</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/864831','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/864831"><span><span class="hlt">Dust</span> feed mechanism</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Milliman, Edward M.</p> <p>1984-01-01</p> <p>The invention is a <span class="hlt">dust</span> feed device for delivery of a uniform supply of <span class="hlt">dust</span> for long periods of time to an aerosolizing means for production of a <span class="hlt">dust</span> suspension. The device utilizes at least two tandem containers having spiral brushes within the containers which transport the <span class="hlt">dust</span> from a supply to the aerosolizer means.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1814268G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1814268G"><span>Mineral <span class="hlt">dust</span> transport in the Arctic modelled with FLEXPART</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Groot Zwaaftink, Christine; Grythe, Henrik; Stohl, Andreas</p> <p>2016-04-01</p> <p>Aeolian transport of mineral <span class="hlt">dust</span> is suggested to play an important role in many processes. For instance, mineral aerosols affect the radiation balance of the atmosphere, and mineral deposits influence ice sheet mass balances and terrestrial and ocean ecosystems. While many efforts have been done to model global <span class="hlt">dust</span> transport, relatively little attention has been given to mineral <span class="hlt">dust</span> in the Arctic. Even though this region is more remote from the world's major <span class="hlt">dust</span> sources and <span class="hlt">dust</span> concentrations may be lower than elsewhere, effects of mineral <span class="hlt">dust</span> on for instance the radiation balance can be highly relevant. Furthermore, there are substantial local sources of <span class="hlt">dust</span> in or close to the Arctic (e.g., in Iceland), whose impact on Arctic <span class="hlt">dust</span> concentrations has not been studied in detail. We therefore aim to estimate contributions of different source regions to mineral <span class="hlt">dust</span> in the Arctic. We have developed a <span class="hlt">dust</span> mobilization routine in combination with the Lagrangian dispersion model FLEXPART to make such estimates. The lack of details on soil properties in many areas requires a simple routine for global simulations. However, we have paid special attention to the <span class="hlt">dust</span> sources on Iceland. The mobilization routine does account for topography, snow cover and soil moisture effects, in addition to meteorological parameters. FLEXPART, driven with operational meteorological data from European Centre for Medium-Range Weather Forecasts, was used to do a three-year global <span class="hlt">dust</span> simulation for the years 2010 to 2012. We assess the model performance in terms of surface concentration and deposition at several locations spread over the globe. We will discuss how deposition and <span class="hlt">dust</span> <span class="hlt">load</span> patterns in the Arctic change throughout seasons based on the source of the <span class="hlt">dust</span>. Important source regions for mineral <span class="hlt">dust</span> found in the Arctic are not only the major desert areas, such as the Sahara, but also local bare-soil regions. From our model results, it appears that total <span class="hlt">dust</span> <span class="hlt">load</span> in the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFM.P14A..06R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFM.P14A..06R"><span>Electric <span class="hlt">Dust</span> Devils and <span class="hlt">Dust</span> Storms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Renno, N. O.; Yana, C.</p> <p>2004-12-01</p> <p>Electrical fields measurements in terrestrial <span class="hlt">dust</span> devils show that they maintain tremendous charge separation and that their electric fields exceeds the breakdown potential (~10 kV/m) of the Martian atmosphere (Farrell et al., 2002, 2003; Krauss et al., 2002; Renno et al., 2004). Typical Martian <span class="hlt">dust</span> devils are be up to 100 times larger and much stronger than the small terrestrial analogues. Martian <span class="hlt">dust</span> devils have higher <span class="hlt">dust</span> content and may produce even stronger electrical fields. Indeed, the <span class="hlt">dust</span> devils observed in the Pathfinder images have about 700 times the <span class="hlt">dust</span> content of the local background atmosphere (Metzger et al., 1999). Thus, strong charge separations and electric-field breakdown are likely to occur on Martian <span class="hlt">dust</span> devils and <span class="hlt">dust</span> storms. Our theory (Renno et al., 2004) and laboratory experiments in a Mars chamber shows that collisions between sand and <span class="hlt">dust</span> particles produce non-thermal microwave radiation. The non-thermal microwave emission allows not only the indirect detection of electric activity but also the determination of the physical properties of Martian sand and <span class="hlt">dust</span> by remote sensing. Besides being geologically important, electrically charged Martian <span class="hlt">dust</span> devils and <span class="hlt">dust</span> storms are potential hazards to Landers and will be dangerous to future astronauts exploring its surface. Indeed, the design of adequate mechanical and electrical systems for these Landers cannot progress effectively without a better understanding of Martian <span class="hlt">dust</span> devils and <span class="hlt">dust</span> storms. Moreover, ancillary phenomena associated with electrically charged vortices can ionize atmospheric gases and might have important implications for atmosphere chemistry and even habitability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EPJWC..4606003H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EPJWC..4606003H"><span><span class="hlt">Dust</span> Dynamics in Kelvin-Helmholtz Instabilities</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hendrix, Tom; Keppens, Rony</p> <p>2013-04-01</p> <p>The Kelvin-Helmholtz instability (KHI) is a fluid instability which arises when two contacting flows have different tangential velocities. As shearing flows are very common in all sorts of (astro)physical fluid setups, the KHI is frequently encountered. In many astrophysical fluids the gas fluid in <span class="hlt">loaded</span> with additional <span class="hlt">dust</span> particles. Here we study the influence of these <span class="hlt">dust</span> particles on the initiation of the KHI, as well as the effect the KHI has on the density distribution of <span class="hlt">dust</span> species in a range of different particle sizes. This redistribution by the instability is of importance in the formation of <span class="hlt">dust</span> structures in astrophysical fluids. To study the effect of <span class="hlt">dust</span> on the linear and nonlinear phase of the KHI, we use the multi-fluid <span class="hlt">dust</span> + gas module of the MPI-AMRVAC [1] code to perform 2D and 3D simulations of KHI in setups with physical quantities relevant to astrophysical fluids. A clear dependency on <span class="hlt">dust</span> sizes is seen, with larger <span class="hlt">dust</span> particles displaying significantly more clumping than smaller ones.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27773252','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27773252"><span>Ultrasonic assisted dispersive solid-phase microextraction of Eriochrome Cyanine R from water sample on ultrasonically synthesized <span class="hlt">lead</span> (II) dioxide nanoparticles <span class="hlt">loaded</span> on activated carbon: Experimental design methodology.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bahrani, Sonia; Ghaedi, Mehrorang; Mansoorkhani, Mohammad Javad Khoshnood; Asfaram, Arash; Bazrafshan, Ali Akbar; Purkait, Mihir Kumar</p> <p>2017-01-01</p> <p>The present research focus on designing an appropriate dispersive solid-phase microextraction (UA-DSPME) for preconcentration and determination of Eriochrome Cyanine R (ECR) in aqueous solutions with aid of sonication using <span class="hlt">lead</span> (II) dioxide nanoparticles <span class="hlt">loaded</span> on activated carbon (PbO-NPs-AC). This material was fully identified with XRD and SEM. Influence of pH, amounts of sorbent, type and volume of eluent, and sonication time on response properties were investigated and optimized by central composite design (CCD) combined with surface response methodology using STATISTICA. Among different solvents, dimethyl sulfoxide (DMSO) was selected as an efficient eluent, which its combination by present nanoparticles and application of ultrasound waves led to enhancement in mass transfer. The predicted maximum extraction (100%) under the optimum conditions of the process variables viz. pH 4.5, eluent 200μL, adsorbent dosage 2.5mg and 5min sonication was close to the experimental value (99.50%). at optimum conditions some experimental features like wide 5-2000ngmL(-1) ECR, low detection limit (0.43ngmL(-1), S/N=3:1) and good repeatability and reproducibility (relative standard deviation, <5.5%, n=12) indicate versatility in successful applicability of present method for real sample analysis. Investigation of accuracy by spiking known concentration of ECR over 200-600ngmL(-1) gave mean recoveries from 94.850% to 101.42% under optimal conditions. The procedure was also applied for the pre-concentration and subsequent determination of ECR in tap and waste waters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001DPS....33.5703G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001DPS....33.5703G"><span>A Novel <span class="hlt">Dust</span> Telescope</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grün, E.; Srama, R.; Krüger, H.; Kempf, S.; Harris, D.; Conlon, T.; Auer, S.</p> <p>2001-11-01</p> <p><span class="hlt">Dust</span> particles in space, like photons, are born at remote sites in space and time. From knowledge of the <span class="hlt">dust</span> particles' birthplace and the particles' bulk properties, we can learn about the remote environment out of which the particles were formed. This approach is carried out by means of a <span class="hlt">dust</span> telescope on a <span class="hlt">dust</span> observatory in space. A <span class="hlt">dust</span> telescope is a combination of a <span class="hlt">dust</span> trajectory sensor together with a chemical composition analyzer for <span class="hlt">dust</span> particles. A novel <span class="hlt">dust</span> telescope is described. It consists of a highly sensitive <span class="hlt">dust</span> trajectory sensor, and a large area chemical <span class="hlt">dust</span> analyzer. It can provide valuable information about the particles' birthplace which may not be accessible by other techniques. <span class="hlt">Dust</span> particles' trajectories are determined by the measurement of the electric signals that are induced when a charged grain flies through an appropriately configured electrode systems. After the successful identification of a few charged micron-sized <span class="hlt">dust</span> grains in space by the Cassini Cosmic <span class="hlt">Dust</span> Analyzer, this <span class="hlt">dust</span> telescope has a ten fold increased sensitivity of charge detection (10-16 Coulombs) and will be able to obtain trajectories for sub-micron sized <span class="hlt">dust</span> grains. State-of-the art <span class="hlt">dust</span> chemical analyzers have sufficient mass resolution to resolve ions with atomic mass numbers above 100. However, since their impact areas are small they can analyze statistically meaningful numbers of grains only in the <span class="hlt">dust</span>-rich environments of comets or ringed planets. Therefore, this <span class="hlt">dust</span> telescope includes a large area (0.1 m2) chemical <span class="hlt">dust</span> analyzer of mass resolution > 100 that will allow us to obtain statistically significant measurements of interplanetary and interstellar <span class="hlt">dust</span> grains in space.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23146184','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23146184"><span>Evaluation of laser-induced breakdown spectroscopy (LIBS) for measurement of silica on filter samples of coal <span class="hlt">dust</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Stipe, Christopher B; Miller, Arthur L; Brown, Jonathan; Guevara, Edward; Cauda, Emanuele</p> <p>2012-11-01</p> <p>Airborne silica <span class="hlt">dust</span> (quartz) is common in coal mines and represents a respiratory hazard that can <span class="hlt">lead</span> to silicosis, a potentially fatal lung disease. With an eye toward developing a portable monitoring device for rapid analysis of silica <span class="hlt">dust</span>, laser-induced breakdown spectroscopy (LIBS) was used to quantify quartz in coal <span class="hlt">dust</span> samples collected on filter media. Pure silica (Min-U-Sil™ 5), Georgia kaolin, and Pittsburgh-4 and Illinois-6 coal <span class="hlt">dusts</span> were deposited separately and at multiple mass <span class="hlt">loadings</span> onto 37-mm polyvinylchloride (PVC) filters. LIBS-generated silicon emission was monitored at 288.16 nm, and non-silica contributions to that signal from kaolinite were removed by simultaneously detecting aluminum. Measurements of the four samples were used to calculate limits of detection (LOD) for silicon and aluminum of approximately 0.08 μg/cm(2) and 0.05 μg/cm(2), respectively (corresponding to 0.16 μg/cm(2) and 0.20 μg/cm(2) for silica and kaolinite, respectively). Relative errors of prediction are around 10%. Results demonstrate that LIBS can dependably quantify silica on filter samples of coal <span class="hlt">dust</span> and confirm that accurate quantification can be achieved for very lightly <span class="hlt">loaded</span> samples, which supports the potential application of LIBS for rapid, in-field monitoring.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4689623','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4689623"><span>Evaluation of Laser-Induced Breakdown Spectroscopy (LIBS) for Measurement of Silica on Filter Samples of Coal <span class="hlt">Dust</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Stipe, Christopher B.; Miller, Arthur L.; Brown, Jonathan; Guevara, Edward; Cauda, Emanuele</p> <p>2015-01-01</p> <p>Airborne silica <span class="hlt">dust</span> (quartz) is common in coal mines and represents a respiratory hazard that can <span class="hlt">lead</span> to silicosis, a potentially fatal lung disease. With an eye toward developing a portable monitoring device for rapid analysis of silica <span class="hlt">dust</span>, laser-induced breakdown spectroscopy (LIBS) was used to quantify quartz in coal <span class="hlt">dust</span> samples collected on filter media. Pure silica (Min-U-Sil™ 5), Georgia kaolin, and Pittsburgh-4 and Illinois-6 coal <span class="hlt">dusts</span> were deposited separately and at multiple mass <span class="hlt">loadings</span> onto 37-mm polyvinylchloride (PVC) filters. LIBS-generated silicon emission was monitored at 288.16 nm, and non-silica contributions to that signal from kaolinite were removed by simultaneously detecting aluminum. Measurements of the four samples were used to calculate limits of detection (LOD) for silicon and aluminum of approximately 0.08 µg/cm2 and 0.05 µg/cm2, respectively (corresponding to 0.16 µg/cm2 and 0.20 µg/cm2 for silica and kaolinite, respectively). Relative errors of prediction are around 10%. Results demonstrate that LIBS can dependably quantify silica on filter samples of coal <span class="hlt">dust</span> and confirm that accurate quantification can be achieved for very lightly <span class="hlt">loaded</span> samples, which supports the potential application of LIBS for rapid, in-field monitoring. PMID:23146184</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016sros.confE.134B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016sros.confE.134B"><span><span class="hlt">Dust</span> grains from the heart of supernovae</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bocchio, Marco; Marassi, Stefania; Schneider, Raffaella; Bianchi, Simone; Limongi, Marco; Chieffi, A.</p> <p>2016-06-01</p> <p><span class="hlt">Dust</span> grains are classically thought to form in the winds of asymptotic giant branch (AGB) stars. However, there is increasing evidence today for <span class="hlt">dust</span> formation in supernovae (SNe). To establish the relative importance of these two classes of stellar sources of <span class="hlt">dust</span>, it is important to know the fraction of freshly formed <span class="hlt">dust</span> in SN ejecta that is able to survive the passage of the reverse shock and be injected in the interstellar medium. We have developed a new code (GRASH_Rev) which follows the newly-formed <span class="hlt">dust</span> evolution throughout the supernova explosion until the merging of the forward shock with the circumstellar ISM. We have considered four well studied SNe in the Milky Way and Large Magellanic Cloud: SN1987A, CasA, the Crab Nebula, and N49. For all the simulated models, we find good agreement with observations and estimate that between 1 and 8% of the observed mass will survive, <span class="hlt">leading</span> to a SN <span class="hlt">dust</span> production rate of (3.9± 3.7)×10^(-4) MM_{⊙})/yr in the Milky Way. This value is one order of magnitude larger than the <span class="hlt">dust</span> production rate by AGB stars but insufficient to counterbalance the <span class="hlt">dust</span> destruction by SNe, therefore requiring <span class="hlt">dust</span> accretion in the gas phase.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA04092&hterms=Avalanches&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DAvalanches','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA04092&hterms=Avalanches&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DAvalanches"><span><span class="hlt">Dust</span> Avalanches</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2003-01-01</p> <p><p/> [figure removed for brevity, see original site] <p/>Crater wall <span class="hlt">dust</span> avalanches in southern Arabia Terra.<p/>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.<p/>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.<p/>Image information: VIS instrument. Latitude 10.3, Longitude 24.5 East (335.5 West). 19 meter/pixel resolution.<p/></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA04092&hterms=Avalanches&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DAvalanches','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA04092&hterms=Avalanches&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DAvalanches"><span><span class="hlt">Dust</span> Avalanches</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2003-01-01</p> <p><p/> [figure removed for brevity, see original site] <p/>Crater wall <span class="hlt">dust</span> avalanches in southern Arabia Terra.<p/>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.<p/>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.<p/>Image information: VIS instrument. Latitude 10.3, Longitude 24.5 East (335.5 West). 19 meter/pixel resolution.<p/></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.6531I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.6531I"><span><span class="hlt">Dust</span> particle dynamics in atmospheric <span class="hlt">dust</span> devils</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Izvekova, Yulia; Popel, Sergey</p> <p>2016-04-01</p> <p><span class="hlt">Dust</span> particle dynamics is modeled in the <span class="hlt">Dust</span> Devils (DDs). DD is a strong, well-formed, and relatively long-lived whirlwind, ranging from small (half a meter wide and a few meters tall) to large (more than 100 meters wide and more than 1000 meters tall) in Earth's atmosphere. We develop methods for the description of <span class="hlt">dust</span> particle charging in DDs, discuss the ionization processes in DDs, and model charged <span class="hlt">dust</span> particle motion. Our conclusions are consistent with the fact that DD can lift a big amount of <span class="hlt">dust</span> from the surface of a planet into its atmosphere. On the basis of the model we perform calculations and show that DDs are important mechanism for <span class="hlt">dust</span> uplift in the atmospheres of Earth and Mars. Influence of DD electric field on dynamics of <span class="hlt">dust</span> particles is investigated. It is shown that influence of the electric field on <span class="hlt">dust</span> particles trajectories is significant near the ground. At some altitude (more then a quarter of the height of DD) influence of the electric field on <span class="hlt">dust</span> particles trajectories is negligible. For the calculation of the dynamics of <span class="hlt">dust</span> electric field can be approximated by effective dipole located at a half of the height of DD. This work was supported by the Russian Federation Presidential Program for State Support of Young Scientists (project no. MK-6935.2015.2).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1241167','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1241167"><span><span class="hlt">Lead</span> sources, behaviors, and socioeconomic factors in relation to blood <span class="hlt">lead</span> of native american and white children: a community-based assessment of a former mining area.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Malcoe, Lorraine Halinka; Lynch, Robert A; Keger, Michelle Crozier; Skaggs, Valerie J</p> <p>2002-01-01</p> <p><span class="hlt">Lead</span> poisoning prevention requires knowledge of <span class="hlt">lead</span> sources and of appropriate residential <span class="hlt">lead</span> standards. Data are severely lacking on <span class="hlt">lead</span> sources for Native American children, many of whom live in rural areas. Further, the relation of mining waste to blood <span class="hlt">lead</span> concentrations (BPbs) of rural children is controversial. In collaboration with the eight tribes of northeastern Oklahoma, we assessed <span class="hlt">lead</span> sources and their effects on BPbs for rural Native American and White children living in a former mining region. Venous blood <span class="hlt">lead</span>, residential environmental (soil, <span class="hlt">dust</span>, paint, water), and caregiver interview (e.g., hand-to-mouth behaviors, socioeconomic conditions) data were obtained from a representative sample of 245 children 1-6 years of age. BPbs ranged from 1 to 24 microg/dL. There were no ethnic differences in BPbs (p= 0.48) nor any patterns of excess <span class="hlt">lead</span> sources for Native American or White children. Multiple linear regression analyses indicated that mean soil <span class="hlt">lead</span>, mean floor <span class="hlt">lead</span> <span class="hlt">loading</span>, mouthing behaviors, caregivers' education, and residence in former mining towns were all strongly associated with BPbs. Logistic regression results showed mean floor <span class="hlt">dust</span> <span class="hlt">lead</span> <span class="hlt">loading</span> greater than or equal to 10.1 microg/ft(2) (odds ratio [OR], 11.4; 95% confidence interval [CI], 3.5-37.3), and yard soil <span class="hlt">lead</span> >165.3 mg/kg (OR, 4.1; CI, 1.3-12.4) were independently associated with BPbs greater than or equal to 10 microg/dL. We also found strong interactions between soil <span class="hlt">lead</span> and poverty (p= 0.005), and <span class="hlt">dust</span> and soil sources (p= 0.02). Our findings indicate that soil and <span class="hlt">dust</span> <span class="hlt">lead</span> derived largely from mining waste pose a health hazard to Native American and White children, and that current residential <span class="hlt">dust</span> <span class="hlt">lead</span> standards are insufficient to adequately protect children. Moreover, our finding that poor children are especially vulnerable to <span class="hlt">lead</span> exposures suggests that residential standards should consider interactions among socioeconomic conditions and <span class="hlt">lead</span> sources if</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.P23B2134H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.P23B2134H"><span><span class="hlt">Dust</span> Accumulation and Cleaning of the MER Opportunity Solar Array</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Herman, J.</p> <p>2015-12-01</p> <p>The solar array of the NASA Mars Exploration Rover (MER) Opportunity was expected to accumulate a sufficient quantity of <span class="hlt">dust</span> after ninety Martian days (sols) such that it could no longer provide enough energy to guarantee continued surface operations. Instead, due in part to low <span class="hlt">dust</span> accumulation rates and numerous <span class="hlt">dust</span> cleaning events, Opportunity continues to operate on the Martian surface for over 4000 sols (over six Mars years). During this time period, the rover experienced six Martian winters and several <span class="hlt">dust</span> storms. Because the sources of solar energy loss are known, the solar array energy output offers a method to scientifically estimate the <span class="hlt">loading</span> and aeolian removal of <span class="hlt">dust</span> from the solar array each sol. We will discuss the accumulation of <span class="hlt">dust</span> on the solar panels as a proxy for <span class="hlt">dust</span> movement at Meridiani Planum over the course of the entire mission to date.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.P23A1911H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.P23A1911H"><span><span class="hlt">Dust</span> Accumulation and Cleaning of the MER Spirit Solar Array</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Herman, J. A.; Lemmon, M. T.; Johnson, J. R.; Cantor, B. A.; Stella, P. M.; Chin, K. B.; Wood, E. G.</p> <p>2012-12-01</p> <p>The solar array of the NASA Mars Exploration Rover (MER) Spirit was expected to accumulate so much <span class="hlt">dust</span> after ninety Martian days (sols) that it could no longer provide enough energy to guarantee continued surface operations. Instead, due in part to low <span class="hlt">dust</span> accumulation rates and numerous <span class="hlt">dust</span> cleaning events, Spirit carried out surface operations for over 2200 sols (over three Mars years). During this time period, the rover experienced four Martian winters and several <span class="hlt">dust</span> storms. Because the sources of solar energy loss are known, the solar array energy output offers a tool to quantitatively estimate the <span class="hlt">loading</span> and aeolian removal of <span class="hlt">dust</span> from the solar array each sol. We will discuss the accumulation of <span class="hlt">dust</span> on the solar panels as a proxy for <span class="hlt">dust</span> movement at Gusev Crater over the course of the entire mission.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JAfES..99..724R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JAfES..99..724R"><span>Assessing the human health risk for aluminium, zinc and <span class="hlt">lead</span> in outdoor <span class="hlt">dusts</span> collected in recreational sites used by children at an industrial area in the western part of the Bassin Minier de Provence, France</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reis, A. P.; Patinha, C.; Noack, Y.; Robert, S.; Dias, A. C.; Ferreira da Silva, E.</p> <p>2014-11-01</p> <p>The Western part of the “Bassin Minier de Provence”, a former coal mining area, is still occupied by old polluting industries such as a coal-fired power plant and an alumina factory. In 2011 a preliminary outdoor <span class="hlt">dust</span> survey was carried out in the area as the first step to an exposure and health risk assessment study. <span class="hlt">Dust</span> samples were taken at 19 sites distributed across the study area, depending on the location of recreational areas used by children to play outdoors. Pseudo-total concentrations of Al, Zn and Pb were determined by ICP-MS and bioaccessible concentrations were estimated using the Unified BARGE Method. Exposure was calculated according to a scenario evaluation approach for <span class="hlt">dust</span> ingestion and dermal contact routes. Estimation of health risk for exposure to Al, Zn and Pb in outdoor <span class="hlt">dust</span> was based on the summation of individual risks for the oral and dermal routes. Results show that Al occurs in very high concentrations but mainly innon-bioaccessible forms, especially near the alumina plant. Zinc and Pb occur in low-average levels but mainly in bioaccessible forms. The estimated potential risk decreases according to Pb ≫ Al > Zn and is lower for the ingestion route. The preliminary results presented in this study indicate that, for Al and Zn, the outdoor <span class="hlt">dusts</span> of the BMP represent an acceptable risk to children's health. However, the estimated hazard quotients suggest that there is some health risk associated to environmental Pb.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5162138','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5162138"><span>Measured effects of <span class="hlt">dust</span> on the performance of radiant barriers installed on top of attic insulation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Levins, W.P. ); Hall, J.A. )</p> <p>1990-01-01</p> <p>The rate of <span class="hlt">dust</span> accumulation and the effect of this <span class="hlt">dust</span> accumulation on a horizontal radiant barrier (HRB) are of special interest because the HRB may perform better in both summer and winter than a truss radiant barrier (TRB), is much easier to install for retrofits in existing homes, and requires less radiant barrier (RB) material than a TRB. However, an HRB has two important potential disadvantages-condensation during winter, which might cause structural damage, and <span class="hlt">dust</span> accumulation which could significantly degrade thermal performance. Results of a winter moisture field test were reported previously by the authors of this paper. <span class="hlt">Dusted</span> HRB performance was tested in small 48 ft{sub 2} test cells in the summer of 1987. The <span class="hlt">dust</span> <span class="hlt">loadings</span>, resultant HRB emissivity and relative attic heat fluxes are presented. The results indicate that <span class="hlt">dust</span> accumulation may not be a prohibitive problem for HRB installations. However, the researchers believed further study of this subject was needed. A national laboratory conducted tests on <span class="hlt">dusted</span> HRBs at three research houses near Oak Ridge, Tennessee, during the summer of 1988. Results showed that the lighter <span class="hlt">dust</span> <span class="hlt">loading</span> increased total house cooling <span class="hlt">loads</span>, compared to a clean HRB, by 2.3%. The heavier <span class="hlt">dust</span> <span class="hlt">loading</span> increased house cooling <span class="hlt">loads</span> by 8.4%, again compared to a clean HRB. However, horizontal radiant barriers with these <span class="hlt">dust</span> <span class="hlt">loadings</span> still decreased house cooling <span class="hlt">loads</span> by 7% when compared to the same house with no radiant barrier.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=GL-2002-001347&hterms=ocean+life&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Docean%2Blife','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=GL-2002-001347&hterms=ocean+life&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Docean%2Blife"><span><span class="hlt">Dust</span> and Ocean Plants</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2002-01-01</p> <p>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 <span class="hlt">dust</span>. In this map, areas with high levels of chlorophyll from phytoplankton and high levels of <span class="hlt">dust</span> deposition (high correlation coefficients) are indicated in dark brown. <span class="hlt">Dust</span> 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 <span class="hlt">lead</span> 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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=GL-2002-001347&hterms=plant+science&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dplant%2Bscience','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=GL-2002-001347&hterms=plant+science&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dplant%2Bscience"><span><span class="hlt">Dust</span> and Ocean Plants</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2002-01-01</p> <p>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 <span class="hlt">dust</span>. In this map, areas with high levels of chlorophyll from phytoplankton and high levels of <span class="hlt">dust</span> deposition (high correlation coefficients) are indicated in dark brown. <span class="hlt">Dust</span> 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 <span class="hlt">lead</span> 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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28575928','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28575928"><span>Impact of <span class="hlt">dust</span> and smoke mixing on column-integrated aerosol properties from observations during a severe wildfire episode over Valencia (Spain).</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gómez-Amo, J L; Estellés, V; Marcos, C; Segura, S; Esteve, A R; Pedrós, R; Utrillas, M P; Martínez-Lozano, J A</p> <p>2017-12-01</p> <p>The most destructive wildfire experienced in Spain since 2004 occurred close to Valencia in summer 2012. A total of 48.500ha were affected by two wildfires, which were mostly active during 29-30 June. The fresh smoke plume was detected at the Burjassot measurement station simultaneously to a severe <span class="hlt">dust</span> episode. We propose an empirical method to evaluate the <span class="hlt">dust</span> and smoke mixing and its impact on the microphysical and optical properties. For this, we combine direct-sun measurements with a Cimel CE-318 sun-photometer with an inversion methodology, and the Mie theory to derive the column-integrated size distribution, single scattering albedo (SSA) and asymmetry parameter (g). The mixing of <span class="hlt">dust</span> and smoke greatly increased the aerosol <span class="hlt">load</span> and modified the background aerosol properties. Mineral <span class="hlt">dust</span> increased the aerosol optical depth (AOD) up to 1, while the smoke plume caused an extreme AOD peak of 8. The size distribution of the mixture was bimodal, with a fine and coarse modes dominated by the smoke particles and mineral <span class="hlt">dust</span>, respectively. The SSA and g for the <span class="hlt">dust</span>-smoke mixture show a marked sensitivity on the smoke mixing-ratio, mainly at longer wavelengths. Mineral <span class="hlt">dust</span> and smoke share a similar SSA at 440nm (~0.90), but with opposite spectral dependency. A small <span class="hlt">dust</span> contribution to the total AOD substantially affects the SSA of the mixture, and also SSA at 1020nm increases from 0.87 to 0.95. This <span class="hlt">leads</span> to a different spectral behaviour of SSA that changes from positive (smoke plume) to negative (<span class="hlt">dust</span>), depending on the <span class="hlt">dust</span> and smoke mixing-ratio. Copyright © 2017 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ApJ...842...11S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ApJ...842...11S"><span>Heating of Porous Icy <span class="hlt">Dust</span> Aggregates</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sirono, Sin-iti</p> <p>2017-06-01</p> <p>At the beginning of planetary formation, highly porous <span class="hlt">dust</span> aggregates are formed through coagulation of <span class="hlt">dust</span> grains. Outside the snowline, the main component of an aggregate is H2O ice. Because H2O ice is formed in amorphous form, its thermal conductivity is extremely small. Therefore, the thermal conductivity of an icy <span class="hlt">dust</span> aggregate is low. There is a possibility of heating inside an aggregate owing to the decay of radionuclides. It is shown that the temperature increases substantially inside an aggregate, <span class="hlt">leading</span> to crystallization of amorphous ice. During the crystallization, the temperature further increases sufficiently to continue sintering. The mechanical properties of icy <span class="hlt">dust</span> aggregates change, and the collisional evolution of <span class="hlt">dust</span> aggregates is affected by the sintering.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21251212','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21251212"><span>Evolution of <span class="hlt">Dust</span> Structures from Room to Cryogenic Temperatures</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Antipov, S. N.; Asinovskii, E. I.; Kirillin, A. V.; Markovets, V. V.; Petrov, O. F.; Fortov, V. E.</p> <p>2008-09-07</p> <p>In this work dusty plasma of dc glow discharge at the temperatures in the range of 4.2-300 K was experimentally and numerically investigated. As it was shown in the experiments, the deep cooling of discharge tube walls <span class="hlt">leads</span> to dramatic change of dusty plasma properties. In particular, sufficient increase of <span class="hlt">dust</span> particle kinetic temperature (by about an order) and <span class="hlt">dust</span> density (by several orders) was observed at low (cryogenic) temperatures. At 4.2 K, this can <span class="hlt">lead</span> to the forming of a super dense <span class="hlt">dust</span> structures with novel properties. Numerical simulations of charging process, <span class="hlt">dust</span> charge fluctuation and screening of <span class="hlt">dust</span> particle charge in plasma were made in dependence with the neutral gas temperature and <span class="hlt">dust</span> density. The main attention was given to proper ion-atom collision analysis that allows us to investigate mechanisms of <span class="hlt">dust</span> structure transformation observed in the cryogenic experiments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19970026865','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19970026865"><span>Kuiper Belt <span class="hlt">Dust</span> Grains as a Source of Interplanetary <span class="hlt">Dust</span> Particles</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Liou, Jer-Chyi; Zook, Herbert A.; Dermott, Stanley F.</p> <p>1996-01-01</p> <p>The recent discovery of the so-called Kuiper belt objects has prompted the idea that these objects produce <span class="hlt">dust</span> grains that may contribute significantly to the interplanetary <span class="hlt">dust</span> population. In this paper, the orbital evolution of <span class="hlt">dust</span> grains, of diameters 1 to 9 microns, that originate in the region of the Kuiper belt is studied by means of direct numerical integration. Gravitational forces of the Sun and planets, solar radiation pressure, as well as Poynting-Robertson drag and solar wind drag are included. The interactions between charged <span class="hlt">dust</span> grains and solar magnetic field are not considered in the model. Because of the effects of drag forces, small <span class="hlt">dust</span> grains will spiral toward the Sun once they are released from their large parent bodies. This motion <span class="hlt">leads</span> <span class="hlt">dust</span> grains to pass by planets as well as encounter numerous mean motion resonances associated with planets. Our results show that about 80% of the Kuiper belt grains are ejected from the Solar System by the giant planets, while the remaining 20% of the grains evolve all the way to the Sun. Surprisingly, the latter <span class="hlt">dust</span> grains have small orbital eccentricities and inclinations when they cross the orbit of the Earth. This makes them behave more like asteroidal than cometary-type <span class="hlt">dust</span> particles. This also enhances their chances of being captured by the Earth and makes them a possible source of the collected interplanetary <span class="hlt">dust</span> particles; in particular, they represent a possible source that brings primitive/organic materials from the outer Solar System to the Earth. When collisions with interstellar <span class="hlt">dust</span> grains are considered, however, Kuiper belt <span class="hlt">dust</span> grains around 9 microns appear likely to be collisionally shattered before they can evolve toward the inner part of the Solar System. The collision destruction can be applied to Kuiper belt grains up to about 50 microns. Therefore, Kuiper belt <span class="hlt">dust</span> grains within this range may not be a significant part of the interplanetary <span class="hlt">dust</span> complex in the inner Solar</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUSM.A52A..03O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUSM.A52A..03O"><span>Airborne <span class="hlt">Dust</span> Modified the North American Climate During the 1930's <span class="hlt">Dust</span> Bowl</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>O'Brien, T. A.; Solmon, F.; Sloan, L. C.; Snyder, M. A.</p> <p>2007-05-01</p> <p>In the 1930's <span class="hlt">Dust</span> Bowl, drought in Mid-Western North America, in conjunction with wide-scale planting of drought-vulnerable crops, resulted in massive <span class="hlt">dust</span> storms. The presence of <span class="hlt">dust</span> in the atmosphere may have directly altered the energy budget of North America by the scattering and absorption of radiation and thus may have acted as a feedback to the regional drought conditions. Through a climate modeling sensitivity study of North American climate investigating the impact of airborne <span class="hlt">dust</span> during the 1930's (using a regional model, RegCM3), we find that areas with moderate to high <span class="hlt">dust-loading</span> have reduced surface temperatures (~1K) and reduced evapotranspiration (~0.5 mm/day). We also find spatially-coherent, statistically significant changes in precipitation patterns over eastern North America during Spring, Summer, and Fall: areas gain and lose as much as 2 mm/day of precipitation. We are working on a more detailed analysis to determine the causal relationship(s) between airborne <span class="hlt">dust</span> and precipitation patterns; we hypothesize that the spatially non-uniform change in the energy budget, caused by <span class="hlt">dust</span> <span class="hlt">loading</span>, modifies regional dynamics and indirectly modifies precipitation patterns.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..DPPTO7005M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..DPPTO7005M"><span>Charged <span class="hlt">Dust</span> Aggregate Interactions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Matthews, Lorin; Hyde, Truell</p> <p>2015-11-01</p> <p>A proper understanding of the behavior of <span class="hlt">dust</span> particle aggregates immersed in a complex plasma first requires a knowledge of the basic properties of the system. Among the most important of these are the net electrostatic charge and higher multipole moments on the <span class="hlt">dust</span> aggregate as well as the manner in which the aggregate interacts with the local electrostatic fields. The formation of elongated, fractal-like aggregates levitating in the sheath electric field of a weakly ionized RF generated plasma discharge has recently been observed experimentally. The resulting data has shown that as aggregates approach one another, they can both accelerate and rotate. At equilibrium, aggregates are observed to levitate with regular spacing, rotating about their long axis aligned parallel to the sheath electric field. Since gas drag tends to slow any such rotation, energy must be constantly fed into the system in order to sustain it. A numerical model designed to analyze this motion provides both the electrostatic charge and higher multipole moments of the aggregate while including the forces due to thermophoresis, neutral gas drag, and the ion wakefield. This model will be used to investigate the ambient conditions <span class="hlt">leading</span> to the observed interactions. This research is funded by NSF Grant 1414523.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MNRAS.469..630A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MNRAS.469..630A"><span><span class="hlt">Dust</span> dynamics and evolution in H ii regions - II. Effects of dynamical coupling between <span class="hlt">dust</span> and gas</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Akimkin, V. V.; Kirsanova, M. S.; Pavlyuchenkov, Ya. N.; Wiebe, D. S.</p> <p>2017-07-01</p> <p>In this paper, we extend the study initiated in Paper I by modelling grain ensemble evolution in a dynamical model of an expanding H ii region and checking the effects of momentum transfer from <span class="hlt">dust</span> to gas. The radiation pressure on the <span class="hlt">dust</span>, the <span class="hlt">dust</span> drift and the lug on the gas by the <span class="hlt">dust</span> are all important processes that should be considered simultaneously to describe the dynamics of H ii regions. By accounting for the momentum transfer from the <span class="hlt">dust</span> to the gas, the expansion time of the H ii region is notably reduced (for our model of RCW 120, the time to reach the observed radius of the H ii region is reduced by a factor of 1.5). Under the common approximation of frozen <span class="hlt">dust</span>, where there is no relative drift between the <span class="hlt">dust</span> and gas, the radiation pressure from the ionizing star drives the formation of the very deep gas cavity near the star. Such a cavity is much less pronounced when the <span class="hlt">dust</span> drift is taken into account. The <span class="hlt">dust</span> drift <span class="hlt">leads</span> to the two-peak morphology of the <span class="hlt">dust</span> density distribution and significantly reduces the <span class="hlt">dust</span>-to-gas ratio in the ionized region (by a factor of 2 to 10). The <span class="hlt">dust</span>-to-gas ratio is larger for higher temperatures of the ionizing star since the <span class="hlt">dust</span> grains have a larger electric charge and are more strongly coupled to the gas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eosweb.larc.nasa.gov/project/misr/gallery/california_dust_and_ash','SCIGOV-ASDC'); return false;" href="https://eosweb.larc.nasa.gov/project/misr/gallery/california_dust_and_ash"><span>California <span class="hlt">Dust</span> and Ash</span></a></p> <p><a target="_blank" href="http://eosweb.larc.nasa.gov/">Atmospheric Science Data Center </a></p> <p></p> <p>2014-05-15</p> <p>article title:  Airborne <span class="hlt">Dust</span> and Ash over Southern California     ... during late fall and winter swept large amounts of <span class="hlt">dust</span> and ash across the skies of San Diego and over the Pacific Ocean on November 27, ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA03086.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA03086.html"><span><span class="hlt">Dust</span> on the Move</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2005-11-02</p> <p>NASA 2001 Mars Odyssey spacecraft shows that the <span class="hlt">dust</span> avalanches found on this crater rim have exposed darker rocky material on an otherwise <span class="hlt">dust</span> coated slope. This unnamed crater is located east of Schiaparelli Crater.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=10534&hterms=Pillows&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DPillows','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=10534&hterms=Pillows&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DPillows"><span><span class="hlt">Dust</span> Plume off Mauritania</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2007-01-01</p> <p>A thick plume of <span class="hlt">dust</span> blew off the coast of Mauritania in western Africa on October 2, 2007. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite observed the <span class="hlt">dust</span> plume as it headed toward the southwest over the Atlantic Ocean. In this image, the <span class="hlt">dust</span> varies in color from nearly white to medium tan. The <span class="hlt">dust</span> plume is easier to see over the dark background of the ocean, but the plume stretches across the land surface to the east, as well. The <span class="hlt">dust</span> plume's structure is clearest along the coastline, where relatively clear air pockets separate distinct puffs of <span class="hlt">dust</span>. West of that, individual pillows of <span class="hlt">dust</span> push together to form a more homogeneous plume. Near its southwest tip, the plume takes on yet another shape, with stripes of pale <span class="hlt">dust</span> fanning out toward the northwest. Occasional tiny white clouds dot the sky overhead, but skies are otherwise clear.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010PhyS...82e5501P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010PhyS...82e5501P"><span>Influence of <span class="hlt">dust</span> particles on glow discharge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Polyakov, D. N.; Shumova, V. V.; Vasilyak, L. M.; Fortov, V. E.</p> <p>2010-11-01</p> <p>The gas discharge-<span class="hlt">dust</span> particle interaction for a dc discharge in air with micron-sized particles is investigated. The plasma of the dc column is described in the frame of diffusion approximation combined with the orbital motion limited approximation for ion and electron flow on the <span class="hlt">dust</span> component surface. The problem is solved for <span class="hlt">dust</span> particles of 2 μm radius, embedded in a uniform glow discharge column with a diameter of 16 mm at air pressure 0.5 torr, discharge current 0.5-3 mA and particle concentration up to 105 cm-3. The current-voltage characteristics as an easy-to-observe measure of the nonlocal <span class="hlt">dust</span> influence on the total amount of charge carriers in the discharge, as well as the radial distributions of plasma components in the dc discharge, are calculated for different <span class="hlt">dust</span> concentrations and discharge currents. The results are compared with recently published experimental data. The presence of <span class="hlt">dust</span> particles <span class="hlt">leads</span> to an increase of the longitudinal electric field due to additional loss of ions and electrons. A decrease of the radial electric field within the <span class="hlt">dust</span> cloud under the action of <span class="hlt">dust</span> particles results in an essential change of the electron concentration profile, down to the appearance of the local minimum at the axis of the discharge.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SSRv..203...39M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SSRv..203...39M"><span>Field Measurements of Terrestrial and Martian <span class="hlt">Dust</span> Devils</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Murphy, Jim; Steakley, Kathryn; Balme, Matt; Deprez, Gregoire; Esposito, Francesca; Kahanpää, Henrik; Lemmon, Mark; Lorenz, Ralph; Murdoch, Naomi; Neakrase, Lynn; Patel, Manish; Whelley, Patrick</p> <p>2016-11-01</p> <p>Surface-based measurements of terrestrial and martian <span class="hlt">dust</span> devils/convective vortices provided from mobile and stationary platforms are discussed. Imaging of terrestrial <span class="hlt">dust</span> devils has quantified their rotational and vertical wind speeds, translation speeds, dimensions, <span class="hlt">dust</span> <span class="hlt">load</span>, and frequency of occurrence. Imaging of martian <span class="hlt">dust</span> devils has provided translation speeds and constraints on dimensions, but only limited constraints on vertical motion within a vortex. The longer mission durations on Mars afforded by long operating robotic landers and rovers have provided statistical quantification of vortex occurrence (time-of-sol, and recently seasonal) that has until recently not been a primary outcome of more temporally limited terrestrial <span class="hlt">dust</span> devil measurement campaigns. Terrestrial measurement campaigns have included a more extensive range of measured vortex parameters (pressure, wind, morphology, etc.) than have martian opportunities, with electric field and direct measure of <span class="hlt">dust</span> abundance not yet obtained on Mars. No martian robotic mission has yet provided contemporaneous high frequency wind and pressure measurements. Comparison of measured terrestrial and martian <span class="hlt">dust</span> devil characteristics suggests that martian <span class="hlt">dust</span> devils are larger and possess faster maximum rotational wind speeds, that the absolute magnitude of the pressure deficit within a terrestrial <span class="hlt">dust</span> devil is an order of magnitude greater than a martian <span class="hlt">dust</span> devil, and that the time-of-day variation in vortex frequency is similar. Recent terrestrial investigations have demonstrated the presence of diagnostic <span class="hlt">dust</span> devil signals within seismic and infrasound measurements; an upcoming Mars robotic mission will obtain similar measurement types.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.5334H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.5334H"><span>Mixing and Deposition of Saharan <span class="hlt">Dust</span> during Transatlantic Transport</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Heinold, Bernd; Schepanski, Kerstin; Gieseler, Daniel; Ulrich, Max</p> <p>2017-04-01</p> <p>Mineral <span class="hlt">dust</span> from arid and semi-arid regions plays an important environmental role due to its ability to alter the Earth's energy budget by aerosol-cloud-radiation interactions as well as due to its impact on the biogeochemical cycle and air quality. The Sahara desert is the world's main <span class="hlt">dust</span> source contributing at least 50% to the global <span class="hlt">dust</span> <span class="hlt">load</span>. Large amounts of <span class="hlt">dust</span> are carried towards the Caribbean within the Saharan Air Layer (SAL), with maximum transport in late boreal spring and early summer. During long-range transport, the <span class="hlt">dust</span> particles are transformed by aging and mixing, which may have significant but as yet unquantified effects on the <span class="hlt">dust</span> impact on radiation, cloud properties, and the biogeochemical processes of ecosystems. This study focuses on the important role of mixing and deposition processes on the distribution, lifetime, and particle properties of mineral <span class="hlt">dust</span>. Regional <span class="hlt">dust</span> modelling and trajectory analysis are used to investigate the long-range transport of Saharan <span class="hlt">dust</span> across the Atlantic Ocean towards the Caribbean. Specifically, we address the questions of (1) how the Saharan <span class="hlt">dust</span> export is influenced by the atmospheric circulation over West Africa and (2) which role the different removal and mixing processes play during long-range transport? Modelling the emission, transport, and deposition of Saharan <span class="hlt">dust</span> as well as the effect of <span class="hlt">dust</span> radiative forcing is performed with the regional model COSMO-MUSCAT. The COSMO-MUSCAT simulations are combined with a LAGRANTO trajectory analysis. The consistent dataset is then evaluated to study the boundary layer impact on deposition and <span class="hlt">dust</span>-cloud interactions along transport paths. The results show that as the source activity, <span class="hlt">dust</span> deposition is driven by the atmospheric circulation patterns over West Africa. Convective mixing controls dry deposition in the tropics and can explain sporadic deposition events in the subtropics. Overall, this study provides an improved model-based assessment of the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JGRD..11713206S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JGRD..11713206S"><span>Numerical simulation of spatial-temporal distribution of <span class="hlt">dust</span> aerosol and its direct radiative effects on East Asian climate</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sun, Hui; Pan, Zaitao; Liu, Xiaodong</p> <p>2012-07-01</p> <p>The latest regional climate model version 4 (RegCM4) coupled with a <span class="hlt">dust</span> module developed at the International Center for Theoretical Physics (ICTP, Italy) is used to simulate the spatial-temporal distribution of <span class="hlt">dust</span> aerosol and its climatic impact through direct radiative forcing over East Asia. <span class="hlt">Dust</span> coupled and uncoupled experiments are carried out for the past decade (2000-2009). Comparison with satellite observed aerosol optical depth (AOD) shows that the coupled RegCM4 better reproduces spatial distribution of Asian <span class="hlt">dust</span> <span class="hlt">loading</span> that has been poorly resolved by general circulation models (GCM), capturing three surface <span class="hlt">dust</span> concentration (SDC) centers in the Taklimakan desert, western Inner Mongolia, and northern Xinjiang respectively, with maximum values greater than 1000μg m-3 in spring. The negative surface shortwave (SW) irradiance is strongest in spring over East Asia. Its -20 W m-2 forcing near <span class="hlt">dust</span> source centers results in surface temperature cooling by 0.8°C from spring through summer. SW irradiance at the top of the atmosphere (TOA) is also negative with a minimum value of up to -8 W m-2in North China. <span class="hlt">Dust</span> aerosol induced cooling <span class="hlt">leads</span> to the formation of a cyclonic circulation in the lower troposphere in Northwest China that further excites downstream an anticyclonic circulation (the Yellow River Loop) and a cyclonic circulation (East China Sea, ECS). The northeasterly flow in southern China straddled by the anticyclone and cyclone acts to weaken the southwest monsoon in southeastern China and the surrounding sea. Supported by the <span class="hlt">dust</span>-induced circulations, precipitation increases in cyclonic regions in Northwest China and ECS and decreases in the anticyclonic north-central China.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title40-vol12/pdf/CFR-2010-title40-vol12-sec63-1544.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title40-vol12/pdf/CFR-2010-title40-vol12-sec63-1544.pdf"><span>40 CFR 63.1544 - Standards for fugitive <span class="hlt">dust</span> sources.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-07-01</p> <p>... in place to control fugitive <span class="hlt">dust</span> emissions from the sources listed in paragraphs (a)(1) through (a... place to control fugitive <span class="hlt">dust</span> sources required as part of a State implementation plan for <span class="hlt">lead</span> shall... sources. (a) Each owner or operator of a primary <span class="hlt">lead</span> smelter shall prepare, and at all times...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1169503','SCIGOV-DOEDE'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1169503"><span>Niamey <span class="hlt">Dust</span> Observations</span></a></p> <p><a target="_blank" href="http://www.osti.gov/dataexplorer">DOE Data Explorer</a></p> <p>Flynn, Connor</p> <p>2008-10-01</p> <p>Niamey aerosol are composed of two main components: <span class="hlt">dust</span> due to the proximity of the Sahara Desert, and soot from local and regional biomass burning. The purpose of this data product is to identify when the local conditions are dominated by the <span class="hlt">dust</span> component so that the properties of the <span class="hlt">dust</span> events can be further studied.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=telescope&pg=5&id=EJ722144','ERIC'); return false;" href="https://eric.ed.gov/?q=telescope&pg=5&id=EJ722144"><span><span class="hlt">Dust</span> in the Universe</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Hemenway, Mary Kay; Armosky, Brad J.</p> <p>2004-01-01</p> <p>Space is seeming less and less like empty space as new discoveries and reexaminations fill in the gaps. And, ingenuity and technology, like the Spitzer Space Telescope, is allowing examination of the far reaches of the Milky Way and beyond. Even <span class="hlt">dust</span> is getting its due, but not the <span class="hlt">dust</span> everyone is familiar with. People seldom consider the <span class="hlt">dust</span> in…</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=born+AND+stars&id=EJ722144','ERIC'); return false;" href="http://eric.ed.gov/?q=born+AND+stars&id=EJ722144"><span><span class="hlt">Dust</span> in the Universe</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Hemenway, Mary Kay; Armosky, Brad J.</p> <p>2004-01-01</p> <p>Space is seeming less and less like empty space as new discoveries and reexaminations fill in the gaps. And, ingenuity and technology, like the Spitzer Space Telescope, is allowing examination of the far reaches of the Milky Way and beyond. Even <span class="hlt">dust</span> is getting its due, but not the <span class="hlt">dust</span> everyone is familiar with. People seldom consider the <span class="hlt">dust</span> in…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eosweb.larc.nasa.gov/project/misr/gallery/middle_east_dust','SCIGOV-ASDC'); return false;" href="https://eosweb.larc.nasa.gov/project/misr/gallery/middle_east_dust"><span>Middle East <span class="hlt">Dust</span></span></a></p> <p><a target="_blank" href="http://eosweb.larc.nasa.gov/">Atmospheric Science Data Center </a></p> <p></p> <p>2013-04-16</p> <p>... only some of the <span class="hlt">dust</span> over eastern Syria and southeastern Turkey can be discerned. The <span class="hlt">dust</span> is much more obvious in the center panel, ... 18, 2002 - A large <span class="hlt">dust</span> plume extends across Syria and Turkey. project:  MISR category:  gallery ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/8299207','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/8299207"><span>Perspectives on <span class="hlt">lead</span> toxicity.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lockitch, G</p> <p>1993-10-01</p> <p><span class="hlt">Lead</span> toxicity causes hematological, gastrointestinal, and neurological dysfunction in adults and children. Symptoms are usually noted with blood <span class="hlt">lead</span> greater than 1.93 mumol/L. Severe or prolonged exposure may also cause chronic nephropathy, hypertension, and reproductive impairment. <span class="hlt">Lead</span> inhibits enzymes; alters cellular calcium metabolism; stimulates synthesis of binding proteins in kidney, brain, and bone; and slows nerve conduction. Less severe exposure to <span class="hlt">lead</span>, designated by blood <span class="hlt">lead</span> levels of 0.48-0.96 mumol/L, has been implicated in poor pregnancy outcome, impaired neurobehavioral development, reduced stature in young children, and higher blood pressure in adults. Biochemical and systemic effects of high and low level <span class="hlt">lead</span> toxicity are described. <span class="hlt">Dust</span>, water, and paint chips are still major sources of <span class="hlt">lead</span> but <span class="hlt">lead</span> from folk remedies, cosmetics, food supplements, food preparation utensils, and improperly prepared infant formula has caused epidemic and sporadic severe <span class="hlt">lead</span> toxicity. Screening for pediatric low level <span class="hlt">lead</span> exposure requires measurement of blood <span class="hlt">lead</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MNRAS.465.1089B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MNRAS.465.1089B"><span>On the dynamics of <span class="hlt">dust</span> during protostellar collapse</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bate, Matthew R.; Lorén-Aguilar, Pablo</p> <p>2017-02-01</p> <p>The dynamics of <span class="hlt">dust</span> and gas can be quite different from each other when the <span class="hlt">dust</span> is poorly coupled to the gas. In protoplanetary discs, it is well known that this decoupling of the <span class="hlt">dust</span> and gas can <span class="hlt">lead</span> to diverse spatial structures and <span class="hlt">dust</span>-to-gas ratios. In this paper, we study the dynamics of <span class="hlt">dust</span> and gas during the earlier phase of protostellar collapse, before a protoplanetary disc is formed. We find that for <span class="hlt">dust</span> grains with sizes ≲ 10 μm, the <span class="hlt">dust</span> is well coupled during the collapse of a rotating, pre-stellar core and there is little variation of the <span class="hlt">dust</span>-to-gas ratio during the collapse. However, if larger grains are present, they may have trajectories that are very different from the gas during the collapse, <span class="hlt">leading</span> to mid-plane settling and/or oscillations of the <span class="hlt">dust</span> grains through the mid-plane. This may produce variations in the <span class="hlt">dust</span>-to-gas ratio and very different distributions of large and small <span class="hlt">dust</span> grains at the very earliest stages of star formation, if large grains are present in pre-stellar cores.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1910270V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1910270V"><span><span class="hlt">Dust</span> aerosol-radiation-clouds-precipitation interactions over the Mediterranean</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Valentini, Chiara; Baró, Rocío; Palacios-Peña, Laura; José Gómez-Navarro, Juan; María López-Romero, José; Montávez, Juan Pedro; Jiménez-Guerrero, Pedro</p> <p>2017-04-01</p> <p><span class="hlt">Dust</span> intrusions from African desert regions have an impact on the whole Mediterranean Basin and its climate. They cause an anomalous increase of aerosol <span class="hlt">load</span> in the tropospheric column and have the potential to change the energy fluxes in the Earth-atmosphere system by modifying cloud microphysical properties, such as the cloud liquid water path (CLWP), cloud fraction (CFRAC), cloud top temperature (CTT), droplet number concentration (CDNC), or cloud particle size distribution (CPSD). Through aerosol-radiation-cloud interactions, <span class="hlt">dust</span> can modify convective and large-scale precipitation under certain conditions, thus affecting the hydrological cycle. In this work, desert <span class="hlt">dust</span> outbreaks occurred in October2010 over the whole Mediterranean Basin has been studied with the objective of quantifying the influence of including <span class="hlt">dust</span> interactions in a regional on-line coupled climate/chemistry model on several variables: convective precipitation, CLWP, CFRAC and CDNC. The focus is set on characterizing the impacts of aerosol indirect effects on the radiative budget. A set of three WRF-Chem simulations differing only in the inclusion (or not) of aerosol-radiation (ARI) and the aerosol-cloud interactions (ACI) has been carried out. The comparison between simulation results show a satisfying agreement when compared with satellite observations, and supports the skills of the model to estimate the African <span class="hlt">dust</span> contribution over the Mediterranean. Differences between the ARI+ACI and the base case (not including aerosol-radiation-cloud interactions) suggest variations around +/- 15 mm/day in convective precipitation for several events. For instance, considering ARI+ACI <span class="hlt">leads</span> to a generalized reduction of the cloud liquid water path (-50 kg/kg over the areas affected by the <span class="hlt">dust</span> aerosols) and modified patterns of clouds (differences between -65% and +35% in the CFRAC). Also, the low estimated significance of the changes observed between the diverse simulations over certain areas</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995ShWav...5..249L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995ShWav...5..249L"><span>Deflagration to detonation transition fueled by <span class="hlt">dust</span> layers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Y.-C.; Harbaugh, A. S.; Alexander, C. G.; Kauffman, C. W.; Sichel, M.</p> <p>1995-12-01</p> <p>The roles which <span class="hlt">dust</span> layers play in severe <span class="hlt">dust</span> explosions were investigated in a 70 m long and 30 cm inside diameter horizontal Flame Acceleration Tube (FAT) with one end closed and the other end open to the atmosphere. A variety of <span class="hlt">dusts</span> such as corn <span class="hlt">dust</span>, cornstarch, Mira Gel starch, wheat <span class="hlt">dust</span>, and wood flour were layered on the bottom half of the FAT. To initiate the combustion process, a detonation tube filled with a stoichiometric H2/O2 mixture at room temperature and 1 atm pressure was used to ignite a short presuspended <span class="hlt">dust</span> cloud with a <span class="hlt">dust</span> concentration of 500 600 g/m3. Combustion waves generated by this <span class="hlt">dust</span> cloud travel toward the open end of the FAT and are continuously fueled by the <span class="hlt">dust</span>/air mixtures. Flame propagation processes in the FAT were closely monitored by a variety of measuring instruments at different locations. The study demonstrates that stable quasi-detonation were reached in some runs, but self-sustained Chapman-Jouguet detonations were not observed possibly due to the limitation of the tube length. Attempts were made to determine the structure of <span class="hlt">dust</span> detonations fueled by a <span class="hlt">dust</span> layer. Preliminary evidence indicates that for Mira Gel starch the <span class="hlt">leading</span> shock is essentially a triple shock configuration which involves a Mach stem and for wheat and wood <span class="hlt">dusts</span> there possibly exists a multi-headed spin structure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014P%26SS..100....1K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014P%26SS..100....1K"><span>Cosmic <span class="hlt">Dust</span> VI</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kimura, Hiroshi; Kolokolova, Ludmilla; Li, Aigen; Inoue, Akio K.; Jäger, Cornelia</p> <p>2014-10-01</p> <p>This special issue is primarily devoted to the 6th meeting on Cosmic <span class="hlt">Dust</span> (COSMIC <span class="hlt">DUST</span> VI), which was held at CPS (Center for Planetary Science) in Kobe, Japan, on August 5-9, 2013. This meeting was coordinated in an order where a friendly and welcoming atmosphere persuaded the participants of the meeting to develop human relations and interactions among themselves. This has been our interdisciplinary approach to answering the question of where <span class="hlt">dust</span> comes from and where <span class="hlt">dust</span> goes. We briefly review some of the exciting papers presented at the meeting and provide perspectives for the development of cosmic <span class="hlt">dust</span> research.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E3069S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E3069S"><span><span class="hlt">Dust</span> and Planetary Rings</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Siddiqui, Muddassir</p> <p></p> <p>ABSTRACT Space is not empty it has comic radiations (CMBR), <span class="hlt">dust</span> etc. Cosmic <span class="hlt">dust</span> is that type of <span class="hlt">dust</span> which is composed of particles in space which vary from few molecules to 0.1micro metres in size. This type of <span class="hlt">dust</span> is made up of heavier atoms born in the heart of stars and supernova. Mainly it contains <span class="hlt">dust</span> grains and when these <span class="hlt">dust</span> grains starts compacting then it turns to dense clouds, planetary ring <span class="hlt">dust</span> and circumstellar <span class="hlt">dust</span>. <span class="hlt">Dust</span> grains are mainly silicate particles. <span class="hlt">Dust</span> plays a major role in our solar system, for example in zodiacal light, Saturn's B ring spokes, planetary rings at Jovian planets and comets. Observations and measurements of cosmic <span class="hlt">dust</span> in different regions of universe provide an important insight into the Universe's recycling processes. Astronomers consider <span class="hlt">dust</span> in its most recycled state. Cosmic <span class="hlt">dust</span> have radiative properties by which they can be detected. Cosmic <span class="hlt">dusts</span> are classified as intergalactic <span class="hlt">dusts</span>, interstellar <span class="hlt">dusts</span> and planetary rings. A planetary ring is a ring of cosmic <span class="hlt">dust</span> and other small particles orbiting around a planet in flat disc shape. All of the Jovian planets in our solar system have rings. But the most notable one is the Saturn's ring which is the brightest one. In March 2008 a report suggested that the Saturn's moon Rhea may have its own tenuous ring system. The ring swirling around Saturn consists of chunks of ice and <span class="hlt">dust</span>. Most rings were thought to be unstable and to dissipate over course of tens or hundreds of millions of years but it now appears that Saturn's rings might be older than that. The <span class="hlt">dust</span> particles in the ring collide with each other and are subjected to forces other than gravity of its own planet. Such collisions and extra forces tend to spread out the rings. Pluto is not known to have any ring system but some Astronomers believe that New Horizons probe might find a ring system when it visits in 2015.It is also predicted that Phobos, a moon of Mars will break up and form into a planetary ring</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015CliPa..11..869A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015CliPa..11..869A"><span>Twelve thousand years of <span class="hlt">dust</span>: the Holocene global <span class="hlt">dust</span> cycle constrained by natural archives</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Albani, S.; Mahowald, N. M.; Winckler, G.; Anderson, R. F.; Bradtmiller, L. I.; Delmonte, B.; François, R.; Goman, M.; Heavens, N. G.; Hesse, P. P.; Hovan, S. A.; Kang, S. G.; Kohfeld, K. E.; Lu, H.; Maggi, V.; Mason, J. A.; Mayewski, P. A.; McGee, D.; Miao, X.; Otto-Bliesner, B. L.; Perry, A. T.; Pourmand, A.; Roberts, H. M.; Rosenbloom, N.; Stevens, T.; Sun, J.</p> <p>2015-06-01</p> <p> estimate the mass balance of and variability in the global <span class="hlt">dust</span> cycle during the Holocene, with <span class="hlt">dust</span> <span class="hlt">loads</span> ranging from 17.2 to 20.8 Tg between 2000 and 10 000 years ago and with a minimum in the early to mid-Holocene (6000-8000 years ago).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ARep...61...89P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ARep...61...89P"><span><span class="hlt">Dust</span> in galaxy clusters</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Polikarpova, O. L.; Shchekinov, Yu. A.</p> <p>2017-02-01</p> <p>The conditions for the destruction of <span class="hlt">dust</span> in hot gas in galaxy clusters are investigated. It is argued that extinction measurements can be subject to selection effects, hindering their use in obtaining trustworthy estimates of <span class="hlt">dust</span> masses in clusters. It is shown, in particular, that the ratio of the <span class="hlt">dust</span> mass to the extinction M d / S d increases as <span class="hlt">dust</span> grains are disrupted, due to the rapid destruction of small grains. Over long times, this ratio can asymptotically reach values a factor of three higher than the mean value in the interstellar medium in the Galaxy. This lowers <span class="hlt">dust</span>-mass estimates based on measurements of extinction in galaxy clusters. The characteristic lifetime of <span class="hlt">dust</span> in hot cluster gas is determined by its possible thermal isolation by the denser medium of gas fragments within which the <span class="hlt">dust</span> is ejected from galaxies, and can reach 100-300 million years, depending on the kinematics and morphology of the fragments. As a result, the mass fraction of <span class="hlt">dust</span> in hot cluster gas can reach 1-3% of the Galactic value. Over its lifetime, <span class="hlt">dust</span> can also be manifest through its far-infrared emission. The emission characteristics of the <span class="hlt">dust</span> change as it is disrupted, and the ratio of the fluxes at 350 and 850 μm can increase appreciably. This can potentially serve as an indicator of the state of the <span class="hlt">dust</span> and ambient gas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2041327','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2041327"><span>The cytotoxic effects of asbestos and other mineral <span class="hlt">dust</span> in tissue culture cell lines.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Chamberlain, M.; Brown, R. C.</p> <p>1978-01-01</p> <p>The cytotoxic effects of 15 <span class="hlt">dusts</span> have been tested in 2 cell lines. Experimental animal data are available for 11 of the 15 <span class="hlt">dusts</span>. There is a correlation between the cytotoxic activities of the <span class="hlt">dusts</span> and the ability to induce mesothelial tumours following intrapleural injection of the <span class="hlt">dusts</span>. Some preliminary observations on the nature of interaction between the <span class="hlt">dusts</span>, medium components and the cells are reported. It is suggested that the study of the interactions between cells and <span class="hlt">dusts</span> in culture may <span class="hlt">lead</span> to an understanding of the pathogenesis of these <span class="hlt">dusts</span> in man and animals. Images Fig. 2 PMID:656318</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120000821','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120000821"><span><span class="hlt">Dust</span> Mitigation Vehicle</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cardiff, Eric H.</p> <p>2011-01-01</p> <p>A document describes the development and demonstration of an apparatus, called a <span class="hlt">dust</span> mitigation vehicle, for reducing the amount of free <span class="hlt">dust</span> on the surface of the Moon. The <span class="hlt">dust</span> mitigation vehicle would be used to pave surfaces on the Moon to prevent the <span class="hlt">dust</span> from levitating or adhering to surfaces. The basic principle of operation of these apparatuses is to use a lens or a dish mirror to concentrate solar thermal radiation onto a small spot to heat lunar regolith. In the case of the prototype <span class="hlt">dust</span> mitigation vehicle, a Fresnel lens was used to heat a surface layer of regolith sufficiently to sinter or melt <span class="hlt">dust</span> grains into a solid mass. The prototype vehicle has demonstrated paving rates up to 1.8 square meters per day. The proposed flight design of the <span class="hlt">dust</span> mitigation vehicle is also described.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120013196','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120013196"><span>Interstellar <span class="hlt">Dust</span> - A Review</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Salama, Farid</p> <p>2012-01-01</p> <p>The study of the formation and the destruction processes of cosmic <span class="hlt">dust</span> is essential to understand and to quantify the budget of extraterrestrial organic materials. Although <span class="hlt">dust</span> 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 <span class="hlt">dust</span>. 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 <span class="hlt">dust</span> particles, the growth and the destruction processes of interstellar <span class="hlt">dust</span> and the resulting budget of extraterrestrial organic molecules. A review of the properties of <span class="hlt">dust</span> and of the laboratory experiments that are conducted to study the formation processes of <span class="hlt">dust</span> grains from molecular precursors will be given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA06940&hterms=light+formed&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dlight%2Bformed','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA06940&hterms=light+formed&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dlight%2Bformed"><span>Light <span class="hlt">Dust</span> Devil Tracks</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2004-01-01</p> <p><p/> 14 October 2004 Many Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images exhibit wild patterns of dark streaks thought to have formed by the passage of many <span class="hlt">dust</span> devils. The <span class="hlt">dust</span> devils disrupt the <span class="hlt">dust</span> coating the martian surface, leaving behind a streak. However, not all <span class="hlt">dust</span> devils make streaks, and not all <span class="hlt">dust</span> devil streaks are dark. Some are light---it simply depends upon which is darker, the substrate or the <span class="hlt">dust</span> that the spinning vortex disrupts. The example of light-toned <span class="hlt">dust</span> devil streaks shown here is located in southern Schiaparelli Basin near 5.3oS, 343.3oW. The image covers an area about 3 km (1.9 mi) across; sunlight illuminates the scene from the left/upper left.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014APJAS..50..345C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APJAS..50..345C"><span>On large-scale transport of <span class="hlt">dust</span> storms and anthropogenic <span class="hlt">dust</span>-falls over east Asia observed in central Korea in 2009</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chung, Y. S.; Kim, Hak-Sung; Chun, Youngsin</p> <p>2014-05-01</p> <p><span class="hlt">Dust</span> air pollution has been routinely monitored in central Korea for the last two decades. In 2009, there were eight typical episodes of significant <span class="hlt">dust</span> <span class="hlt">loadings</span> in the air: four were caused by <span class="hlt">dust</span> storms from deserts in Mongolia and Northern China, while the remaining were typical cases of anthropogenic air pollution masses arriving from the Yellow Sea and East China. These natural <span class="hlt">dust</span> <span class="hlt">loadings</span> occurred with cool northwesterly airflows in the forward side of an intense anticyclone coming from Mongolia and Siberia. The mean concentrations of the four natural dustfall cases for TSP, PM10 and PM2.5 were 632, 480 and 100 μg m-3, respectively. In contrast, the anthropogenic <span class="hlt">dust</span>-pollution episodes occurred with the warm westerly and southwesterly airflows in the rear side of an anticyclone. This produced a favorable atmospheric and chemical condition for the build-up of anthropogenic <span class="hlt">dust</span> air pollution in the Yellow Sea. The mean concentrations of the four anthropogenic <span class="hlt">dust</span> <span class="hlt">loadings</span> for TSP, PM10 and PM2.5 were 224, 187 and 137 μg m-3, respectively. The contents of fine <span class="hlt">dust</span> <span class="hlt">loadings</span> of PM2.5 were comparatively high in the cases of anthropogenic air pollution. High atmospheric concentrations of fine particles in the atmosphere cause poor visibility and constitute a health hazard. Satellite observations clearly showed the movement of <span class="hlt">dust</span>-pollution masses from Mongolia and Northern China and from the Yellow Sea and East China that caused these <span class="hlt">dust</span> pollution episodes in Korea.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24275707','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24275707"><span>Desert <span class="hlt">dust</span> and human health disorders.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Goudie, Andrew S</p> <p>2014-02-01</p> <p><span class="hlt">Dust</span> storms may originate in many of the world's drylands and have an effect not only on human health in the drylands themselves but also in downwind environments, including some major urban centres, such as Phoenix, Kano, Athens, Madrid, Dubai, Jedda, Tehran, Jaipur, Beijing, Shanghai, Seoul, Taipei, Tokyo, Sydney, Brisbane and Melbourne. In some parts of the world <span class="hlt">dust</span> storms occur frequently throughout the year. They can transport particulate material, pollutants, and potential allergens over thousands of km from source. The main sources include the Sahara, central and eastern Asia, the Middle East, and parts of the western USA. In some parts of the world, though not all, the frequency of <span class="hlt">dust</span> storms is changing in response to land use and climatic changes, and in such locations the health implications may become more severe. Data on the PM10 and P2.5 <span class="hlt">loadings</span> of <span class="hlt">dust</span> events are discussed, as are various pollutants (heavy metals, pesticides, etc.) and biological components (spores, fungi, bacteria, etc.). Particulate <span class="hlt">loadings</span> can far exceed healthy levels. Among the human health effects of <span class="hlt">dust</span> storms are respiratory disorders (including asthma, tracheitis, pneumonia, allergic rhinitis and silicosis) cardiovascular disorders (including stroke), conjunctivitis, skin irritations, meningococcal meningitis, valley fever, diseases associated with toxic algal blooms and mortality and injuries related to transport accidents.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25264172','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25264172"><span>Risk analysis of <span class="hlt">dust</span> explosion scenarios using Bayesian networks.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yuan, Zhi; Khakzad, Nima; Khan, Faisal; Amyotte, Paul</p> <p>2015-02-01</p> <p>In this study, a methodology has been proposed for risk analysis of <span class="hlt">dust</span> 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 <span class="hlt">dust</span> explosions. In this study, the risks of <span class="hlt">dust</span> explosion scenarios are evaluated, taking into account common cause failures and dependencies among root events and possible consequences. Using a diagnostic analysis, <span class="hlt">dust</span> particle properties, oxygen concentration, and safety training of staff are identified as the most critical root events <span class="hlt">leading</span> to <span class="hlt">dust</span> explosions. The probability adaptation concept is also used for sequential updating and thus learning from past <span class="hlt">dust</span> 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 <span class="hlt">dust</span> explosion scenarios, to estimate the envisaged risks, and to identify the vulnerable parts of the system that need additional safety measures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PApGe.tmp..199F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PApGe.tmp..199F"><span>Seasonal Verification of <span class="hlt">Dust</span> Forecast over the Indian Region</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fatima, Hashmi; George, John P.; Rajagopal, E. N.; Basu, Swati</p> <p>2017-07-01</p> <p>The medium-range forecast of the <span class="hlt">dust</span> aerosols over Indian region produced by the NCMRWF numerical weather prediction model with mineral <span class="hlt">dust</span> scheme from May 2013 to May 2014 is examined in this study. Coarse mode aerosol observations are only used for comparison with <span class="hlt">dust</span> forecast with the assumption that coarse mode aerosol over Indian region largely represents <span class="hlt">dust</span> aerosol, especially over the areas of high <span class="hlt">dust</span> <span class="hlt">load</span>. Accuracy and trends of the day-to-day <span class="hlt">dust</span> forecast are studied at three AERONET locations in Indo-Gangetic Plains (IGP) using surface and MODIS satellite retrievals of coarse mode aerosol optical depth for entire one year (May 2013-May 2014). Seasonal mean geographical distribution of the medium-range forecast of <span class="hlt">dust</span> by the model over Indian region is validated with different satellite retrievals for all four seasons. Availability of suitable observations is one of the limiting factors and big challenges for the validation of the <span class="hlt">dust</span> forecast. The main focus of this study is to assess <span class="hlt">dust</span> forecast by the model over Indian region for all seasons, to know the biases and errors of the model forecast for its optimal use. The study finds that model <span class="hlt">dust</span> forecast is comparable to AERONET observations over three locations for all seasons except monsoon season.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.5490K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.5490K"><span>Poleward transport of Saharan <span class="hlt">dust</span> initiated by a Saharan cyclone.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karam Francis, Diana Bou; Chaboureau, Jean-Pierre; Cuesta, Juan</p> <p>2016-04-01</p> <p>To enhance the understanding of the role of Saharan mineral <span class="hlt">dust</span> in the Arctic climate system, this study focuses on <span class="hlt">dust</span> emission and poleward transport associated with an intense Saharan cyclone that occurred over North Africa in early April 2011. Satellites observations at high spatio-temporal resolution are used in this study in order to characterize qualitatively (using MSG-SEVIRI and CALIPSO/CloudSat) and quantitatively (using MODIS and OMI) the <span class="hlt">dust</span> activity over North Africa associated with the Saharan cyclone as well as the transport of <span class="hlt">dust</span> toward the northern pole. Beside the observations, a simulation at high resolution is performed using the MesoNh model in order to estimation the <span class="hlt">dust</span> <span class="hlt">load</span> transported northward and to evaluate the <span class="hlt">dust</span> deposition north to 60°N and its impact on the Albedo. In this study, we identify in new and important mechanism for the transport of <span class="hlt">dust</span> over long distances toward the northern pole: the poleward migration of Saharan cyclones, in which the <span class="hlt">dust</span> is transported toward the Arctic following a newly identified path; across the Northern Atlantic Ocean around the Icelandic Low. This path is to be added to the two preferable paths mentioned in previous studies i.e. through transport across Northern Europe and across the Atlantic Ocean around the Bermuda High. Key words: Arctic, North Africa, <span class="hlt">dust</span> storm, <span class="hlt">dust</span> deposition, surface albedo.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NucFu..55e3014S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NucFu..55e3014S"><span>Studies of <span class="hlt">dust</span> transport in long pulse plasma discharges in the large helical device</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shoji, M.; Kasahara, H.; Tokitani, M.; Seki, T.; Saito, K.; Kamio, S.; Seki, R.; Tanaka, Y.; Pigarov, A.; Smirnov, R.; Kawamura, G.; Tanaka, H.; Masuzaki, S.; Uesugi, Y.; Mutoh, T.; The LHD Experiment Group</p> <p>2015-05-01</p> <p>Three-dimensional trajectories of incandescent <span class="hlt">dust</span> particles in plasmas were observed with stereoscopic fast framing cameras in a large helical device. It proved that the <span class="hlt">dust</span> is located in the peripheral plasma and most of the <span class="hlt">dust</span> moves along the magnetic field lines with acceleration in the direction that corresponds to the plasma flow. ICRF heated long pulse plasma discharges were terminated with the release of large amounts of <span class="hlt">dust</span> from a closed divertor region. After the experimental campaign, the traces of exfoliation of carbon rich mixed-material deposition layers were found in the divertor region. Transport of carbon <span class="hlt">dust</span> is investigated using a modified <span class="hlt">dust</span> transport simulation code, which can explain the observed <span class="hlt">dust</span> trajectories. It also shows that controlling the radius of the <span class="hlt">dust</span> particles to less than 1 mm is necessary to prevent the plasma termination by penetration of <span class="hlt">dust</span> for the long pulse discharges. <span class="hlt">Dust</span> transport simulation including heavy metal <span class="hlt">dust</span> particles demonstrates that high heating power operation is effective for shielding the main plasma from <span class="hlt">dust</span> penetration by an enhanced plasma flow effect and a high heat <span class="hlt">load</span> onto the <span class="hlt">dust</span> particles in the peripheral plasma. It shows a more powerful penetration characteristic of tungsten <span class="hlt">dust</span> particles compared to that of carbon and iron <span class="hlt">dust</span> particles.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://digitalcommons.usu.edu/nrei/vol15/iss1/18','USGSPUBS'); return false;" href="http://digitalcommons.usu.edu/nrei/vol15/iss1/18"><span><span class="hlt">Dust</span> emission at Franklin Lake Playa, Mojave Desert (USA): Response to meteorological and hydrologic changes 2005-2008</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Reynolds, Richard L.; Bogle, Rian C.; Vogel, John; Goldstein, Harland; Yount, James</p> <p>2009-01-01</p> <p>Playa type, size, and setting; playa hydrology; and surface-sediment characteristics are important controls on the type and amount of atmospheric <span class="hlt">dust</span> emitted from playas. Soft, evaporite-rich sediment develops on the surfaces of some Mojave Desert (USA) playas (wet playas), where the water table is shallow (< 4 m). These areas are sources of atmospheric <span class="hlt">dust</span> because of continuous or episodic replenishment of wind-erodible salts and disruption of the ground surface during salt formation by evaporation of ground water. <span class="hlt">Dust</span> emission at Franklin Lake playa was monitored between March 2005 and April 2008. The <span class="hlt">dust</span> record, based on day-time remote digital camera images captured during high wind, and compared with a nearby precipitation record, shows that aridity suppresses <span class="hlt">dust</span> emission. High frequency of <span class="hlt">dust</span> generation appears to be associated with relatively wet periods, identified as either heavy precipitation events or sustained regional precipitation over a few months. Several factors may act separately or in combination to account for this relation. <span class="hlt">Dust</span> emission may respond rapidly to heavy precipitation when the dissolution of hard, wind-resistant evaporite mineral crusts is followed by the development of soft surfaces with thin, newly formed crusts that are vulnerable to wind erosion and (or) the production of loose aggregates of evaporite minerals that are quickly removed by even moderate winds. <span class="hlt">Dust</span> <span class="hlt">loading</span> may also increase when relatively high regional precipitation <span class="hlt">leads</span> to decreasing depth to the water table, thereby increasing rates of vapor discharge, development of evaporite minerals, and temporary softening of playa surfaces. The seasonality of wind strength was not a major factor in <span class="hlt">dust</span>-storm frequency at the playa. The lack of major <span class="hlt">dust</span> emissions related to flood-derived sediment at Franklin Lake playa contrasts with some dry-lake systems elsewhere that may produce large amounts of <span class="hlt">dust</span> from flood sediments. Flood sediments do not commonly</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GeoRL..44.3796S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GeoRL..44.3796S"><span>Change in <span class="hlt">dust</span> seasonality as the primary driver for orbital-scale <span class="hlt">dust</span> storm variability in East Asia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Serno, Sascha; Winckler, Gisela; Anderson, Robert F.; Jaccard, Samuel L.; Kienast, Stephanie S.; Haug, Gerald H.</p> <p>2017-04-01</p> <p>Glacial periods are recognized to be dustier than interglacials, but the conditions <span class="hlt">leading</span> to greater <span class="hlt">dust</span> mobilization are poorly defined. Here we present a new high-resolution <span class="hlt">dust</span> record based on 230Th-normalized 4He flux from Ocean Drilling Program site 882 in the Subarctic North Pacific covering the last 170,000 years. By analogy with modern relationships, we infer the mechanisms controlling orbital-scale <span class="hlt">dust</span> storm variability in East Asia. We propose that orbital-scale <span class="hlt">dust</span> flux variability is the result of an expansion of the <span class="hlt">dust</span> season into summer, in addition to more intense <span class="hlt">dust</span> storms during spring and fall. The primary drivers influencing <span class="hlt">dust</span> flux include summer insolation at subarctic latitudes and variable Siberian alpine glaciation, which together control the cold air reservoir in Siberia. Changes in the extent of the Northern Hemisphere ice sheets may be a secondary control.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-GSFC_20170927_Archive_e001534.jpg.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-GSFC_20170927_Archive_e001534.jpg.html"><span><span class="hlt">Dust</span> storm in the Gobi Desert, China</span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2017-09-27</p> <p>On March 8, 2013 <span class="hlt">dust</span> plumes rose from the Gobi Desert and blew along the China-Mongolia border. Strong winds kept the <span class="hlt">dust</span> aloft for several days, and <span class="hlt">dust</span> appeared as far eastward as Henan Province and as far south as the Sichuan Basin by March 13. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this true-color image on March 9. The <span class="hlt">dust</span> had continued traveling toward the southeast, and the camel-colored plume extended several hundred kilometers into eastern China. In the southeast (lower right corner of this image), the <span class="hlt">dust</span> approached China’s coastal plain. Gray haze hung over that region and although the <span class="hlt">dust</span> likely worsened air quality there, the gray color of the haze suggested other sources, such as urban and industrial smog, and smoke from fires. At least one fire sent a discernible smoke plume eastward, ahead of the <span class="hlt">dust</span>. Credit: NASA/GSFC/Jeff Schmaltz/MODIS Land Rapid Response Team NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a <span class="hlt">leading</span> role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.P31B1414H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.P31B1414H"><span>LDEX: Lunar <span class="hlt">Dust</span> EXperiment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Horanyi, M.; Sternovsky, Z.; Gruen, E.; Srama, R.; Auer, S.; Munsat, T.; Robertson, S.; Wang, X.</p> <p>2008-12-01</p> <p>The lunar <span class="hlt">dust</span> environment is expected to be dominated by submicron sized <span class="hlt">dust</span> particles released from the Moon due to: a) the continuous bombardment by interplanetary <span class="hlt">dust</span>, and b) due to plasma-induced, intense, small-scale electric fields. To a good approximation, the impact-produced ejecta are expected to form a spherically symmetric, continuously present cloud, while the electrically lofted population is expected to be concentrated over the terminators, and remain highly temporally and spatially variable. The Lunar <span class="hlt">Dust</span> EXperiment (LDEX) instrument is proposed for the Lunar Atmosphere and <span class="hlt">Dust</span> Environment Explorer (LADEE) mission for in-situ <span class="hlt">dust</span> detection in orbit around the Moon. LDEX is based on the detection of ions generated in hypervelocity <span class="hlt">dust</span> impacts. The instrument is capable of detecting submicron sized <span class="hlt">dust</span> grains with impact speeds above about 1 km/s. Particles larger than about 0.2 microns can be detected individually, and the parameters of the impact signal yield the mass, velocity, and charge of the <span class="hlt">dust</span>. Smaller <span class="hlt">dust</span> grains, below the detection threshold for individual detection, are measured collectively as an average from a large number of impacts. With the extended detection size range, LDEX can verify the existence of the putative lunar <span class="hlt">dust</span>-exosphere. LDEX has been recently developed at LASP, and it has a high degree of heritage based on similar instruments on the Ulysses and Galileo missions. An engineering prototype version of LDEX is scheduled for testing and calibration at the Heidelberg <span class="hlt">dust</span> accelerator facility. The talk will briefly review the science goals and measurement requirements for in situ <span class="hlt">dust</span> detection, as well as the capabilities of LDEX.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhDT.......401S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhDT.......401S"><span>The Lunar <span class="hlt">Dust</span> Environment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Szalay, Jamey Robert</p> <p></p> <p>Planetary bodies throughout the solar system are continually bombarded by <span class="hlt">dust</span> 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 <span class="hlt">dust</span> 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 <span class="hlt">dust</span> grains. Impacts onto solid surfaces in space generate charged and neutral gas clouds, as well as solid secondary ejecta <span class="hlt">dust</span> particles. Gravitationally bound ejecta clouds forming <span class="hlt">dust</span> exospheres were recognized by in situ <span class="hlt">dust</span> 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 <span class="hlt">Dust</span> and Environment Explorer (LADEE) mission. In this thesis, we first present the measurements taken by the Lunar <span class="hlt">Dust</span> Explorer (LDEX), aboard LADEE, which discovered a permanently present, asymmetric <span class="hlt">dust</span> cloud surrounding the Moon. The global characteristics of the lunar <span class="hlt">dust</span> 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 <span class="hlt">dust</span> 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 <span class="hlt">dust</span> 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 <span class="hlt">dust</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2710682','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2710682"><span>Biological consequences of earlier snowmelt from desert <span class="hlt">dust</span> deposition in alpine landscapes</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Steltzer, Heidi; Landry, Chris; Painter, Thomas H.; Anderson, Justin; Ayres, Edward</p> <p>2009-01-01</p> <p><span class="hlt">Dust</span> deposition to mountain snow cover, which has increased since the late 19th century, accelerates the rate of snowmelt by increasing the solar radiation absorbed by the snowpack. Snowmelt occurs earlier, but is decoupled from seasonal warming. Climate warming advances the timing of snowmelt and early season phenological events (e.g., the onset of greening and flowering); however, earlier snowmelt without warmer temperatures may have a different effect on phenology. Here, we report the results of a set of snowmelt manipulations in which radiation-absorbing fabric and the addition and removal of <span class="hlt">dust</span> from the surface of the snowpack advanced or delayed snowmelt in the alpine tundra. These changes in the timing of snowmelt were superimposed on a system where the timing of snowmelt varies with topography and has been affected by increased <span class="hlt">dust</span> <span class="hlt">loading</span>. At the community level, phenology exhibited a threshold response to the timing of snowmelt. Greening and flowering were delayed before seasonal warming, after which there was a linear relationship between the date of snowmelt and the timing of phenological events. Consequently, the effects of earlier snowmelt on phenology differed in relation to topography, which resulted in increasing synchronicity in phenology across the alpine landscape with increasingly earlier snowmelt. The consequences of earlier snowmelt from increased <span class="hlt">dust</span> deposition differ from climate warming and include delayed phenology, <span class="hlt">leading</span> to synchronized growth and flowering across the landscape and the opportunity for altered species interactions, landscape-scale gene flow via pollination, and nutrient cycling. PMID:19564599</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19564599','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19564599"><span>Biological consequences of earlier snowmelt from desert <span class="hlt">dust</span> deposition in alpine landscapes.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Steltzer, Heidi; Landry, Chris; Painter, Thomas H; Anderson, Justin; Ayres, Edward</p> <p>2009-07-14</p> <p><span class="hlt">Dust</span> deposition to mountain snow cover, which has increased since the late 19(th) century, accelerates the rate of snowmelt by increasing the solar radiation absorbed by the snowpack. Snowmelt occurs earlier, but is decoupled from seasonal warming. Climate warming advances the timing of snowmelt and early season phenological events (e.g., the onset of greening and flowering); however, earlier snowmelt without warmer temperatures may have a different effect on phenology. Here, we report the results of a set of snowmelt manipulations in which radiation-absorbing fabric and the addition and removal of <span class="hlt">dust</span> from the surface of the snowpack advanced or delayed snowmelt in the alpine tundra. These changes in the timing of snowmelt were superimposed on a system where the timing of snowmelt varies with topography and has been affected by increased <span class="hlt">dust</span> <span class="hlt">loading</span>. At the community level, phenology exhibited a threshold response to the timing of snowmelt. Greening and flowering were delayed before seasonal warming, after which there was a linear relationship between the date of snowmelt and the timing of phenological events. Consequently, the effects of earlier snowmelt on phenology differed in relation to topography, which resulted in increasing synchronicity in phenology across the alpine landscape with increasingly earlier snowmelt. The consequences of earlier snowmelt from increased <span class="hlt">dust</span> deposition differ from climate warming and include delayed phenology, <span class="hlt">leading</span> to synchronized growth and flowering across the landscape and the opportunity for altered species interactions, landscape-scale gene flow via pollination, and nutrient cycling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ACPD...1328173I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ACPD...1328173I"><span>Response of acid mobilization of iron-containing mineral <span class="hlt">dust</span> to improvement of air quality projected in the future</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ito, A.; Xu, L.</p> <p>2013-10-01</p> <p>Acidification of <span class="hlt">dust</span> aerosols may increase aerosol iron (Fe) solubility, which is linked to mineral properties. Combustion aerosols can also elevate aerosol iron solubility when aerosol <span class="hlt">loading</span> is low. Here, we use an atmospheric chemical transport model to investigate the deposition of filterable iron and its response to changes in anthropogenic emissions of both combustion aerosols and precursor gases. By introducing three classes of iron-containing minerals into the detailed aerosol chemistry model, we provide a theoretical examination of the effects of different dissolution behaviors on the acid mobilization of iron. Comparisons of modeled Fe dissolution curves with the measured dissolution rates for African (Tibesti) and Asian (Beijing) <span class="hlt">dust</span> samples show overall good agreement under acidic conditions. The improved treatment of Fe in mineral <span class="hlt">dust</span> and its dissolution scheme results in reasonable predictive capability for iron solubility over the oceans in the Northern Hemisphere. Our model results suggest that the improvement of air quality projected in the future will <span class="hlt">lead</span> to a decrease of the filterable iron deposition from iron-containing mineral <span class="hlt">dust</span> to the northeastern Pacific due to less acidification in Asian <span class="hlt">dust</span>, which is mainly associated with the reduction of nitrogen oxides (NOx) emissions. These results could have important implications for iron fertilization of phytoplankton growth, and highlight the necessity of improving the process-based quantitative understanding of the response of the chemical modification in iron-containing minerals to environmental changes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ACP....14.3441I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ACP....14.3441I"><span>Response of acid mobilization of iron-containing mineral <span class="hlt">dust</span> to improvement of air quality projected in the future</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ito, A.; Xu, L.</p> <p>2014-04-01</p> <p>Acidification of <span class="hlt">dust</span> aerosols may increase aerosol iron (Fe) solubility, which is linked to mineral properties. Combustion aerosols can also elevate aerosol iron solubility when aerosol <span class="hlt">loading</span> is low. Here, we use an atmospheric chemical transport model to investigate the deposition of filterable iron and its response to changes in anthropogenic emissions of both combustion aerosols and precursor gases. By introducing three classes of iron-containing minerals into the detailed aerosol chemistry model, we provide a theoretical examination of the effects of different dissolution behaviors on the acid mobilization of iron. Comparisons of modeled Fe dissolution curves with the measured dissolution rates for African, east Asian, and Australian <span class="hlt">dust</span> samples show overall good agreement under acidic conditions. The improved treatment of Fe in mineral <span class="hlt">dust</span> and its dissolution scheme results in reasonable predictive capability for iron solubility over the oceans in the Northern Hemisphere. Our model results suggest that the improvement of air quality projected in the future will <span class="hlt">lead</span> to a decrease of the filterable iron deposition from iron-containing mineral <span class="hlt">dust</span> to the eastern North Pacific due to less acidification in Asian <span class="hlt">dust</span>, which is mainly associated with the reduction of nitrogen oxides (NOx) emissions. These results could have important implications for iron fertilization of phytoplankton growth, and highlight the necessity of improving the process-based quantitative understanding of the response of the chemical modification in iron-containing minerals to environmental changes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014CliPD..10.4277A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014CliPD..10.4277A"><span>Twelve thousand years of <span class="hlt">dust</span>: the Holocene global <span class="hlt">dust</span> cycle constrained by natural archives</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Albani, S.; Mahowald, N. M.; Winckler, G.; Anderson, R. F.; Bradtmiller, L. I.; Delmonte, B.; François, R.; Goman, M.; Heavens, N. G.; Hesse, P. P.; Hovan, S. A.; Kohfeld, K. E.; Lu, H.; Maggi, V.; Mason, J. A.; Mayewski, P. A.; McGee, D.; Miao, X.; Otto-Bliesner, B. L.; Perry, A. T.; Pourmand, A.; Roberts, H. M.; Rosenbloom, N.; Stevens, T.; Sun, J.</p> <p>2014-11-01</p> <p>, with <span class="hlt">dust</span> <span class="hlt">load</span> ranging from 17.1 to 20.5 Tg between 2000 and 10 000 years ago, and a minimum in the Early to Mid-Holocene (6000-8000 years ago).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008cosp...37.1110G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008cosp...37.1110G"><span><span class="hlt">Dust</span> processing and its feedback on interstellar shocks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guillet, Vincent; Jones, Anthony; Pineau Des Forets, Guillaume</p> <p></p> <p>Shocks in the interstellar medium (ISM) have a fundamental impact on the <span class="hlt">dust</span> that they encounter. Supernova-generated shocks in the warm intercloud medium are the principal lifetimedetermining agents for <span class="hlt">dust</span> evolution in the ISM. However, the presence of <span class="hlt">dust</span> can also have a major influence on the structure of the shocks themselves. In this review we focus on the important role of <span class="hlt">dust</span> in shocks and present the results of numerical models that simulate <span class="hlt">dust</span> destruction and processing, and the effect of the <span class="hlt">dust</span> on, shocks in molecular clouds and in the warm intercloud medium. A proper treatment of grain charging, gyration and coupling to the magnetic field determines the details of the <span class="hlt">dust</span> dynamics and therefore the nature of the gas-grain and grain-grain interactions. The resultant processing of <span class="hlt">dust</span> by shocks in the ISM can <span class="hlt">lead</span> to changes in the <span class="hlt">dust</span>-to-gas mass ratio through sputtering and vaporisation, and also to an evolution of the <span class="hlt">dust</span> size distribution through the competition between coagulation and shattering in graingrain collisions. The presence of <span class="hlt">dust</span>, and its processing, can also alter the shock structure and the gas composition. In high velocity shocks propagating through the warm intercloud medium, <span class="hlt">dust</span> is the main coolant in the regions where hydrogen is ionized, until it is fully destroyed by sputtering. The reformation of H2 in the cooling gas depends on the level of <span class="hlt">dust</span> destruction and shattering in the shock. In shocked molecular clouds, the destruction of silicate grains produces shock tracers like SiO. <span class="hlt">Dust</span> grains and their fragments produced by shattering in the shock also affect the coupling between the magnetic field and the neutral gas in multi-fluid shocks. We emphasize the necessity of a detailed modelling of grain charging and dynamics through the shock in order to determine the impact of shocks on the <span class="hlt">dust</span> size distribution, and its feedback on the shock structure and the evolution of the shocked gas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.epa.gov/indoor-air-quality-iaq/leads-impact-indoor-air-quality','PESTICIDES'); return false;" href="https://www.epa.gov/indoor-air-quality-iaq/leads-impact-indoor-air-quality"><span><span class="hlt">Lead</span>'s Impact on Indoor Air Quality</span></a></p> <p><a target="_blank" href="http://www.epa.gov/pesticides/search.htm">EPA Pesticide Factsheets</a></p> <p></p> <p></p> <p><span class="hlt">Lead</span> has long been recognized as a harmful environmental pollutant. There are many ways in which humans are exposed to <span class="hlt">lead</span>: through air, drinking water, food, contaminated soil, deteriorating paint, and <span class="hlt">dust</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24415803','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24415803"><span>The effect of operating conditions on resistance parameters of filter media and limestone <span class="hlt">dust</span> cake for uniformly <span class="hlt">loaded</span> needle felts in a pilot scale test facility at ambient conditions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Saleem, Mahmood; Krammer, Gernot; Tahir, M Suleman</p> <p>2012-09-01</p> <p>Resistance parameters are essential for the prediction of pressure drop in bag filters. The reported values for limestone <span class="hlt">dust</span> differ in magnitude and also depend on operating parameters. In this work, experimental data is provided from a pilot scale pulse-jet regenerated bag filter test facility for three types of needle felts using air and limestone <span class="hlt">dust</span> at ambient conditions. Results reveal that specific resistance of filter media is independent of velocity while the specific resistance of filter cake increases linearly with filtration velocity. Residual pressure drop is almost constant, independent of upper pressure drop limit. The cake resistance at constant velocity fits to a second degree polynomial whereas it increases linearly with the velocity. A linear relation is reported here for all the cases. The resistance of filter cake decreases at higher upper pressure drop limit.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28951148','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28951148"><span>Kinetics of thermal decomposition of some biomasses in an inert environment. An investigation of the effect of <span class="hlt">lead</span> <span class="hlt">loaded</span> by biosorption.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Martín-Lara, María Ángeles; Iáñez-Rodríguez, Irene; Blázquez, Gabriel; Quesada, Lucía; Pérez, Antonio; Calero, Mónica</p> <p>2017-09-23</p> <p>The thermal behavior of some types of raw and <span class="hlt">lead</span>-polluted biomasses typical in south Spain was studied by non-isothermal thermogravimetry. Experiments were carried out in nitrogen atmosphere at three heating rates (5, 10 and 20°C/min). The results of thermogravimetric tests carried out proved that the presence of <span class="hlt">lead</span> did not change the main degradation pathways of selected biomass (almond shell (AS) and olive pomace (OP)). However, from a point of view of mass loss, <span class="hlt">lead</span>-polluted samples showed higher decomposition temperatures and decomposition at higher rate. The determination of activation energies was performed by isoconversional methods of Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS) and Friedman (FR). In general, <span class="hlt">lead</span>-polluted samples showed lower activation energies than raw ones. Then, Coast-Redfern method was applied to determine kinetic function. The kinetic function that seems to determine the mechanism of thermal degradation of main components of all samples was nth order reaction. Finally, a model based on three parallel reactions (for three pseudocomponents) that fit to nth order reactions was evaluated. This model was appropriate to predict the pyrolysis behavior of the raw and <span class="hlt">lead</span>-polluted samples in all pyrolysis conditions studied. Copyright © 2017 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EPSC...10..846S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EPSC...10..846S"><span>In situ <span class="hlt">dust</span> measurements by the Cassini Cosmic <span class="hlt">Dust</span> Analyzer in 2014 and beyond</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Srama, R.</p> <p>2015-10-01</p> <p>Today, the German-<span class="hlt">lead</span> Cosmic <span class="hlt">Dust</span> Analyser (CDA) is operated continuously for 11 years in orbit around Saturn. Many discoveries like the Saturn nanodust streams or the large extended Ering were achieved. CDA provided unique results regarding Enceladus, his plume and the liquid water below the icy crust. In 2014 and 2015 CDA focuses on extended inclination and equatorial scans of the ring particle densities. Furthermore, scans are performed of the Pallene and Helene regions. Special attention is also given to the search of the <span class="hlt">dust</span> cloud around Dione and to the Titan region. Long integration times are needed in order to characterize the flux and composition of exogenous <span class="hlt">dust</span> (including interstellar <span class="hlt">dust</span>) or possible retrograde <span class="hlt">dust</span> particles. Finally, dedicated observation campaigns focus on the coupling of nanodust streams to Saturn's magnetosphere and the search of possible periodicities in the stream data. Saturn's rotation frequency was identified in the impact rate of nanodust particles at a Saturn distance of 40 Saturn radii. A special geometry in 2014-065 <span class="hlt">lead</span> to an occultation of the <span class="hlt">dust</span> stream by the moon Titan and its atmosphere when Titan crossed the line-of-sight between Saturn and Cassini. Here, CDA pointed towards Saturn for the measurement of stream particles. Around closest approach when Cassini was behind Titan, the flux of stream particles went down to zero (Fig. 1). This "<span class="hlt">dust</span> occultation" is a new method to analyse the properties of the stream particles (speed, composition, mass) or the properties of Titans atmosphere (density). Furthermore, the particle trajectories can be constrained for a better analysis of their origin. In the final three years CDA performs exogenous and interstellar <span class="hlt">dust</span> campaigns, studies of the composition and origin of Saturn's main rings by unique ring ejecta measurements, long-duration nano-<span class="hlt">dust</span> stream observations, high-resolution maps of small moon orbit crossings, studies of the <span class="hlt">dust</span> cloud around Dione and studies</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1814601H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1814601H"><span>Intense <span class="hlt">dust</span> episodes in the Mediterranean and possible effects on atmospheric lapse rates</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hatzianastassiou, Nikos; Gkikas, Antonis; Papadimas, Christos D.; Gavrouzou, Maria</p> <p>2016-04-01</p> <p><span class="hlt">Dust</span> aerosols are major contributor to the atmospheric particulate matter, having significant effects on climate and weather patterns as well as on human health, not to mention others like agriculture or ocean chlorophyll. Moreover, these effects are maximized under conditions of massive <span class="hlt">dust</span> concentration in the atmosphere, namely <span class="hlt">dust</span> episodes or events. Such events are caused by uplifting and transport of <span class="hlt">dust</span> from arid and semi-arid areas under favorable synoptic conditions. The Mediterranean basin, nearby to the greatest world deserts of North Africa and Middle East, frequently undergoes <span class="hlt">dust</span> episodes. During such Mediterranean episodes, the number and mass concentration of <span class="hlt">dust</span> is high, due to the proximity of its source areas. The <span class="hlt">dust</span> episodes, through the direct interaction of <span class="hlt">dust</span> primarily withthe shortwave but also with longwave radiation can <span class="hlt">lead</span> to strong local warming in the atmosphere, possibly causing temperature inversion during daytime. The existence of such temperature inversions, associated with intense <span class="hlt">dust</span> episodes in the Mediterranean, is the focus in this study. The methodology followed to achieve the scientific goal of the study consists in the use of a synergy of different data. This synergy enables: (i) the determination of intense <span class="hlt">dust</span> episodes over the Mediterranean, (ii) the investigation and specification of temperature lapse rates and inversions during the days of <span class="hlt">dust</span> episodes and (iii) the identification of vertical distribution of aerosols in the atmosphere over specific locations during the days of the episodes. These objectives are achieved through the use of data from: (i) the AERosol Robotic NETwork (AERONET) network, (ii) the Upper Air Observations (radiosondes) database of the University of Wyoming (UoW) and (iii) the European Aerosol Research Lidar Network (EARLINET) database. The study period spans the years from 2000 to 2013, constrained by the data availability of the databases. A key element of the methodology is the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E3709Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E3709Y"><span>The effect of <span class="hlt">dust</span> charge fluctuations in the near-Enceladus plasma</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yaroshenko, Victoria; Luehr, Hermann</p> <p></p> <p>The geologically active moon Enceladus feeds the most extended, Saturns’ E ring by <span class="hlt">dust</span> particles and creates a specific multispecies plasma environment -the Enceladus plasma torus. The key process of <span class="hlt">dust</span>-plasma interactions is <span class="hlt">dust</span> charging. The grain electrostatic potential in space is usually calculated from the so called orbit-motion limited (OML) model [1]. It is valid for a single particle immersed into collisionless plasmas with Maxwellian electron and ion distributions. Such a parameter regime cannot be directly applied to the conditions relevant for the Enceladus plasma environment and especially, for the dense plume region, where the <span class="hlt">dust</span> density is high, sometimes even exceeding the plasma number density. Generalizing the OML formalism, we examine several new factors that can significantly affect the equilibrium grain charging: (a) multispecies composition of the core plasma, including hot electrons and newborn cold ions; (b) effect of high <span class="hlt">dust</span> number density (c) the role of <span class="hlt">dust</span> size distributions. We also focus on such a specific peculiarity of <span class="hlt">dust</span> charging as charge fluctuations. Since the grain charges are not fixed and can fluctuate, this introduces the crucial difference between ordinary plasma species (electrons and ions) and charged <span class="hlt">dust</span> particles. There are two reasons for such fluctuations. The charging of the grains depends on the local plasma characteristics, and thus some temporal or spatial variations in the plasma parameters ultimately modify numbers of charges acquired by a grain. Some of these effects related to the near-Enceladus plasma environment have recently been discussed [2]. A second reason for charge fluctuations is the discrete nature of the charge carriers. Electrons and ions are absorbed or emitted by the grain surface randomly thus <span class="hlt">leading</span> to stochastic fluctuations of the <span class="hlt">dust</span> net charge. These fluctuations exist always even in a steady-state uniform plasma, and we discuss the statistical characteristics of random <span class="hlt">dust</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PNAS..114.6221P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PNAS..114.6221P"><span>Tropical cyclone activity enhanced by Sahara greening and reduced <span class="hlt">dust</span> emissions during the African Humid Period</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pausata, Francesco S. R.; Emanuel, Kerry A.; Chiacchio, Marc; Diro, Gulilat T.; Zhang, Qiong; Sushama, Laxmi; Stager, J. Curt; Donnelly, Jeffrey P.</p> <p>2017-06-01</p> <p>Tropical cyclones (TCs) can have devastating socioeconomic impacts. Understanding the nature and causes of their variability is of paramount importance for society. However, historical records of TCs are too short to fully characterize such changes and paleo-sediment archives of Holocene TC activity are temporally and geographically sparse. Thus, it is of interest to apply physical modeling to understanding TC variability under different climate conditions. Here we investigate global TC activity during a warm climate state (mid-Holocene, 6,000 yBP) characterized by increased boreal summer insolation, a vegetated Sahara, and reduced <span class="hlt">dust</span> emissions. We analyze a set of sensitivity experiments in which not only solar insolation changes are varied but also vegetation and <span class="hlt">dust</span> concentrations. Our results show that the greening of the Sahara and reduced <span class="hlt">dust</span> <span class="hlt">loadings</span> <span class="hlt">lead</span> to more favorable conditions for tropical cyclone development compared with the orbital forcing alone. In particular, the strengthening of the West African Monsoon induced by the Sahara greening triggers a change in atmospheric circulation that affects the entire tropics. Furthermore, whereas previous studies suggest lower TC activity despite stronger summer insolation and warmer sea surface temperature in the Northern Hemisphere, accounting for the Sahara greening and reduced <span class="hlt">dust</span> concentrations <span class="hlt">leads</span> instead to an increase of TC activity in both hemispheres, particularly over the Caribbean basin and East Coast of North America. Our study highlights the importance of regional changes in land cover and <span class="hlt">dust</span> concentrations in affecting the potential intensity and genesis of past TCs and suggests that both factors may have appreciable influence on TC activity in a future warmer climate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28559352','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28559352"><span>Tropical cyclone activity enhanced by Sahara greening and reduced <span class="hlt">dust</span> emissions during the African Humid Period.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pausata, Francesco S R; Emanuel, Kerry A; Chiacchio, Marc; Diro, Gulilat T; Zhang, Qiong; Sushama, Laxmi; Stager, J Curt; Donnelly, Jeffrey P</p> <p>2017-06-13</p> <p>Tropical cyclones (TCs) can have devastating socioeconomic impacts. Understanding the nature and causes of their variability is of paramount importance for society. However, historical records of TCs are too short to fully characterize such changes and paleo-sediment archives of Holocene TC activity are temporally and geographically sparse. Thus, it is of interest to apply physical modeling to understanding TC variability under different climate conditions. Here we investigate global TC activity during a warm climate state (mid-Holocene, 6,000 yBP) characterized by increased boreal summer insolation, a vegetated Sahara, and reduced <span class="hlt">dust</span> emissions. We analyze a set of sensitivity experiments in which not only solar insolation changes are varied but also vegetation and <span class="hlt">dust</span> concentrations. Our results show that the greening of the Sahara and reduced <span class="hlt">dust</span> <span class="hlt">loadings</span> <span class="hlt">lead</span> to more favorable conditions for tropical cyclone development compared with the orbital forcing alone. In particular, the strengthening of the West African Monsoon induced by the Sahara greening triggers a change in atmospheric circulation that affects the entire tropics. Furthermore, whereas previous studies suggest lower TC activity despite stronger summer insolation and warmer sea surface temperature in the Northern Hemisphere, accounting for the Sahara greening and reduced <span class="hlt">dust</span> concentrations <span class="hlt">leads</span> instead to an increase of TC activity in both hemispheres, particularly over the Caribbean basin and East Coast of North America. Our study highlights the importance of regional changes in land cover and <span class="hlt">dust</span> concentrations in affecting the potential intensity and genesis of past TCs and suggests that both factors may have appreciable influence on TC activity in a future warmer climate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23659966','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23659966"><span>Trace metals in fugitive <span class="hlt">dust</span> from unsurfaced roads in the Viburnum Trend resource mining District of Missouri--implementation of a direct-suspension sampling methodology.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Witt, Emitt C; Wronkiewicz, David J; Pavlowsky, Robert T; Shi, Honglan</p> <p>2013-09-01</p> <p>Fugitive <span class="hlt">dust</span> from 18 unsurfaced roadways in Missouri were sampled using a novel cyclonic fugitive <span class="hlt">dust</span> collector that was designed to obtain suspended bulk samples for analysis. The samples were analyzed for trace metals, Fe and Al, particle sizes, and mineralogy to characterize the similarities and differences between roadways. Thirteen roads were located in the Viburnum Trend (VT) mining district, where there has been a history of contaminant metal <span class="hlt">loading</span> of local soils; while the remaining five roads were located southwest of the VT district in a similar rural setting, but without any mining or industrial process that might contribute to trace metal enrichment. Comparison of these two groups shows that trace metal concentration is higher for <span class="hlt">dusts</span> collected in the VT district. <span class="hlt">Lead</span> is the dominant trace metal found in VT district <span class="hlt">dusts</span> representing on average 79% of the total trace metal concentration, and was found moderately to strongly enriched relative to unsurfaced roads in the non-VT area. Fugitive road <span class="hlt">dust</span> concentrations calculated for the VT area substantially exceed the 2008 Federal ambient air standard of 0.15μgm(-3) for Pb. The pattern of trace metal contamination in fugitive <span class="hlt">dust</span> from VT district roads is similar to trace metal concentrations patterns observed for soils measured more than 40years ago indicating that Pb contamination in the region is persistent as a long-term soil contaminant. Published by Elsevier Ltd.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19940016436&hterms=1587&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%2526%25231587','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19940016436&hterms=1587&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%2526%25231587"><span>On <span class="hlt">dust</span> emissions from the jovian system</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zook, H. A.; Gruen, E.; Baguhl, M.; Balogh, A.; Bame, S. J.; Fechtig, H.; Forsyth, R.; Hanner, M. S.; Horanyi, M.; Kissel, J.</p> <p>1993-01-01</p> <p>As described by Gruen et al., the <span class="hlt">dust</span> impact detector on the Ulysses spacecraft detected a totally unexpected series of <span class="hlt">dust</span> streams in the outer solar system near the orbit of Jupiter. Five considerations <span class="hlt">lead</span> us to believe that the <span class="hlt">dust</span> streams emanate from the jovian system itself: the <span class="hlt">dust</span> streams only occur within about 1 AU of the jovian system, with the strongest stream being the one closest to Jupiter (about 550 R(sub J) away); the direction from which they arrive is never far from the line-of-sight direction to Jupiter; the time period between streams is about 28 (+/- 3) days; the impact velocities are very high--mostly around 40 km/s; and we can think of no cometary, asteroidal, or interstellar source that could give rise to the above four phenomena (such streams have never before been detected).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19850018262','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19850018262"><span><span class="hlt">Dust</span> devils on Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Thomas, P. G.; Gierasch, P.</p> <p>1985-01-01</p> <p>Large columns of <span class="hlt">dust</span> have been discovered rising above plains on Mars. The storms are probably analogous to terrestrial <span class="hlt">dust</span> devils, but their size indicates that they are more similar to tornadoes in intensity. They occur at locations where the soil has been strongly warmed by the Sun, and there the surface is smooth and fine grained. These are the same conditions that favor <span class="hlt">dust</span> devils on Earth. Warm gas from the lowest atmospheric layer converges and rises in a thin column, with intense swirl developing at the edge of the column. In one area a mosaic of Viking images shows 97 vortices in a three day period. This represents a density of vortices of about one in each 900 square kilometers. Thus, these <span class="hlt">dust</span> devils may be important in moving <span class="hlt">dust</span> or starting over <span class="hlt">dust</span> storms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E3628W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E3628W"><span><span class="hlt">Dust</span> Formation and Destruction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wiebe, Dmitry</p> <p></p> <p>Recent infrared and sub-millimeter observations have opened up a new window in <span class="hlt">dust</span> evolution studies. High angular resolution of Spitzer and Herschel space telescopes from near to far-infrared wavelengths allows observing <span class="hlt">dust</span> emission in galactic and extragalactic star-forming complexes, covering a broad range of metallicities, radiation field properties, etc. A wide-scale picture of <span class="hlt">dust</span> evolution starts to arise from these observations. In my contribution I will try to cover major recent advances in studies of <span class="hlt">dust</span> formation and destruction, including such topics as a diverse role of supernovae in <span class="hlt">dust</span> evolution, possibility of <span class="hlt">dust</span> formation and/or growth in molecular clouds, and VSG and PAH evolution in HII regions and complexes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19970003297&hterms=glue&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dglue','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19970003297&hterms=glue&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dglue"><span>Interstellar <span class="hlt">Dust</span>: Physical Processes</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jones, A. P.; Tielens, A. G. G. M.</p> <p>1993-01-01</p> <p><span class="hlt">Dust</span> is formed in stellar environments, and destroyed by sputtering, shattering and vaporization in shock waves due to cloud-cloud collisions and supernova blast waves. <span class="hlt">Dust</span> is also destroyed during star formation. We review the <span class="hlt">dust</span> formation and destruction balance. The calculated destruction time-scale is less than or equal to one billion years and the star <span class="hlt">dust</span> injection time-scale is approx. 2.5 billion years. Hence, the fractions of elemental carbon and silicon locked up in stardust are less than 0.3 and less than 0.15, respectively. An efficient ISM <span class="hlt">dust</span> formation route is therefore implied. In particular, in dense clouds <span class="hlt">dust</span> grows; through the processes of coagulation and the accretion of gas phase molecules e.g. H20, CO, CH4. These icy materials may then be photoprocessed to refractory materials in more diffuse regions. The resulting carbonaceous grain mantle may actually be the glue that holds the coagulated grains together.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5178875','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5178875"><span>Reducing float coal <span class="hlt">dust</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Patts, J.R.; Colinet, J.F.; Janisko, S.J.; Barone, T.L.; Patts, L.D.</p> <p>2016-01-01</p> <p>Controlling float coal <span class="hlt">dust</span> in underground coal mines before dispersal into the general airstream can reduce the risk of mine explosions while potentially achieving a more effective and efficient use of rock <span class="hlt">dust</span>. A prototype flooded-bed scrubber was evaluated for float coal <span class="hlt">dust</span> control in the return of a continuous miner section. The scrubber was installed inline between the face ventilation tubing and an exhausting auxiliary fan. Airborne and deposited <span class="hlt">dust</span> mass measurements were collected over three days at set distances from the fan exhaust to assess changes in float coal <span class="hlt">dust</span> levels in the return due to operation of the scrubber. Mass-based measurements were collected on a per-cut basis and normalized on the basis of per ton mined by the continuous miner. The results show that average float coal <span class="hlt">dust</span> levels measured under baseline conditions were reduced by more than 90 percent when operating the scrubber. PMID:28018004</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19830016208','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19830016208"><span>Aeroelastic <span class="hlt">loads</span> prediction for an arrow wing. Task 3: Evaluation of the Boeing three-dimensional <span class="hlt">leading</span>-edge vortex code</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Manro, M. E.</p> <p>1983-01-01</p> <p>Two separated flow computer programs and a semiempirical method for incorporating the experimentally measured separated flow effects into a linear aeroelastic analysis were evaluated. The three dimensional <span class="hlt">leading</span> edge vortex (LEV) code is evaluated. This code is an improved panel method for three dimensional inviscid flow over a wing with <span class="hlt">leading</span> edge vortex separation. The governing equations are the linear flow differential equation with nonlinear boundary conditions. The solution is iterative; the position as well as the strength of the vortex is determined. Cases for both full and partial span vortices were executed. The predicted pressures are good and adequately reflect changes in configuration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED511669.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED511669.pdf"><span>Renovate Right: Important <span class="hlt">Lead</span> Hazard Information for Families, Child Care Providers and Schools</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>US Environmental Protection Agency, 2008</p> <p>2008-01-01</p> <p><span class="hlt">Lead</span> can affect children's brains and developing nervous systems, causing reduced IQ, learning disabilities, and behavioral problems. <span class="hlt">Lead</span> is also harmful to adults. <span class="hlt">Lead</span> in <span class="hlt">dust</span> is the most common way people are exposed to <span class="hlt">lead</span>. People can also get <span class="hlt">lead</span> in their bodies from <span class="hlt">lead</span> in soil or paint chips. <span class="hlt">Lead</span> <span class="hlt">dust</span> is often invisible. <span class="hlt">Lead</span>-based…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SSRv..203..183R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SSRv..203..183R"><span><span class="hlt">Dust</span> Devil Formation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rafkin, S.; Jemmett-Smith, B.; Fenton, L.; Lorenz, R.; Takemi, T.; Ito, J.; Tyler, D.</p> <p>2016-11-01</p> <p>The essential dynamical characteristic of convective vortices, including <span class="hlt">dust</span> devils, is a highly localized vorticity tube that extends into the vertical. This chapter is concerned with both the generation of vorticity and the subsequent focusing of that vorticity into a tight vortex, and with the environmental conditions that are conducive to the formation of convective vortices in general and <span class="hlt">dust</span> devils in particular. A review of observations, theory, and modeling of <span class="hlt">dust</span> devil formation is provided.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.C43B0678K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.C43B0678K"><span>Physical and Chemical Characteristics of Desert <span class="hlt">Dust</span> Deposited on Mt. Elbrus, Caucasus as Documented in Snow Pit and Shallow Core Records</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kutuzov, S.; Shahgedanova, M.; Mikhalenko, V.; Ginot, P.; Lavrentiev, I.; Popov, G.</p> <p>2013-12-01</p> <p>We present a study of <span class="hlt">dust</span> deposition events and its physical and chemical characteristics in Caucasus Mountains as documented by snow and firn pack at Mt Elbrus. <span class="hlt">Dust</span> samples were collected from the shallow ice cores and snow pits in 2009-2013 at the western Elbrus plateau (5150 m a.s.l.). Particle size distribution and chemical analysis (major ions, trace elements) were completed for each sample using Coulter Counter Multisizer III, scanning electron microscopy (SEM), IC and ICPMS analysis. It was shown that desert <span class="hlt">dust</span> deposition occurred in Caucasus 4-8 times a year and originates from the Northern Sahara and the deserts of the Middle East. Analysis of volumetric particle size distributions showed that the modal values ranged between 2 μm and 4 μm although most samples were characterised by modal values of 2.0-2.8 μm with an average of 2.6 μm. These values are lower than those obtained from the ice cores in central and southern Asia following the deposition of long-travelled <span class="hlt">dust</span> and are closer to those reported for the European Alps and the polar ice cores. All samples containing <span class="hlt">dust</span> have a single mode which is usually interpreted as a single source region. They do not reveal any significant differences between the Saharan and the Middle Eastern sources. The annual average <span class="hlt">dust</span> mass concentrations were 10-15 mg kg-1 which is higher than the average concentrations reported for other mountain regions and this was strongly affected by <span class="hlt">dust</span> deposition events. The deposition of <span class="hlt">dust</span> resulted in elevated concentrations of most ions, especially Ca2+, Mg2+, K+, and sulphates. <span class="hlt">Dust</span> originated from multiple sources in the Middle East including Mesopotamia or passing over the Middle East was characterised by the elevated concentrations of nitrates and ammonia which is related to a high atmospheric <span class="hlt">loads</span> of ammonium emitted by agricultural sources and high concentrations of ammonium in <span class="hlt">dust</span> originating from this region. By contrast, samples of the Saharan <span class="hlt">dust</span> showed</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150002145','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150002145"><span>Operational <span class="hlt">Dust</span> Prediction</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Benedetti, Angela; Baldasano, Jose M.; Basart, Sara; Benincasa, Francesco; Boucher, Olivier; Brooks, Malcolm E.; Chen, Jen-Ping; Colarco, Peter R.; Gong, Sunlin; Huneeus, Nicolas; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20150002145'); toggleEditAbsImage('author_20150002145_show'); toggleEditAbsImage('author_20150002145_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20150002145_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20150002145_hide"></p> <p>2014-01-01</p> <p>Over the last few years, numerical prediction of <span class="hlt">dust</span> aerosol concentration has become prominent at several research and operational weather centres due to growing interest from diverse stakeholders, such as solar energy plant managers, health professionals, aviation and military authorities and policymakers. <span class="hlt">Dust</span> prediction in numerical weather prediction-type models faces a number of challenges owing to the complexity of the system. At the centre of the problem is the vast range of scales required to fully account for all of the physical processes related to <span class="hlt">dust</span>. Another limiting factor is the paucity of suitable <span class="hlt">dust</span> observations available for model, evaluation and assimilation. This chapter discusses in detail numerical prediction of <span class="hlt">dust</span> with examples from systems that are currently providing <span class="hlt">dust</span> forecasts in near real-time or are part of international efforts to establish daily provision of <span class="hlt">dust</span> forecasts based on multi-model ensembles. The various models are introduced and described along with an overview on the importance of <span class="hlt">dust</span> prediction activities and a historical perspective. Assimilation and evaluation aspects in <span class="hlt">dust</span> prediction are also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA03791&hterms=climate+Tornado&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dclimate%2BTornado','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA03791&hterms=climate+Tornado&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dclimate%2BTornado"><span><span class="hlt">Dust</span> Devil Tracks</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2002-01-01</p> <p>(Released 8 May 2002) The Science This image, centered near 50.0 S and 17.7 W displays <span class="hlt">dust</span> devil tracks on the surface. Most of the lighter portions of the image likely have a thin veneer of <span class="hlt">dust</span> settled on the surface. As a <span class="hlt">dust</span> devil passes over the surface, it acts as a vacuum and picks up the <span class="hlt">dust</span>, leaving the darker substrate exposed. In this image there is a general trend of many of the tracks running from east to west or west to east, indicating the general wind direction. There is often no general trend present in <span class="hlt">dust</span> devil tracks seen in other images. The track patterns are quite ephemeral and can completely change or even disappear over the course of a few months. <span class="hlt">Dust</span> devils are one of the mechanisms that Mars uses to constantly pump <span class="hlt">dust</span> into the ubiquitously dusty atmosphere. This atmospheric <span class="hlt">dust</span> is one of the main driving forces of the present Martian climate. The Story Vrrrrooooooooom. Think of a tornado, the cartoon Tasmanian devil, or any number of vacuum commercials that powerfully suck up swirls of <span class="hlt">dust</span> and dirt. That's pretty much what it's like on the surface of Mars a lot of the time. Whirlpools of wind called</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1985Sci...230..175T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1985Sci...230..175T"><span><span class="hlt">Dust</span> devils on Mars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thomas, P.; Gierasch, P. J.</p> <p>1985-10-01</p> <p>Viking Orbiter photographic imagery has confirmed the occurrence of <span class="hlt">dust</span> devils on Mars. The images were of small bright clouds with long, tapered shadows viewed from a nearly-nadir angle. Spectra of the features were consistent with <span class="hlt">dust</span> and not condensates. A maximum height of 6.8 km and width of 1 km were measured. The <span class="hlt">dust</span> devils appeared on smooth planes, and had average dimensions of 2 km height and 200 m diam, carrying 3000 kg of <span class="hlt">dust</span>. The data may be of use in interpreting convective processes on earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA03791&hterms=Tasmanian+devil&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DTasmanian%2Bdevil','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA03791&hterms=Tasmanian+devil&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DTasmanian%2Bdevil"><span><span class="hlt">Dust</span> Devil Tracks</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2002-01-01</p> <p>(Released 8 May 2002) The Science This image, centered near 50.0 S and 17.7 W displays <span class="hlt">dust</span> devil tracks on the surface. Most of the lighter portions of the image likely have a thin veneer of <span class="hlt">dust</span> settled on the surface. As a <span class="hlt">dust</span> devil passes over the surface, it acts as a vacuum and picks up the <span class="hlt">dust</span>, leaving the darker substrate exposed. In this image there is a general trend of many of the tracks running from east to west or west to east, indicating the general wind direction. There is often no general trend present in <span class="hlt">dust</span> devil tracks seen in other images. The track patterns are quite ephemeral and can completely change or even disappear over the course of a few months. <span class="hlt">Dust</span> devils are one of the mechanisms that Mars uses to constantly pump <span class="hlt">dust</span> into the ubiquitously dusty atmosphere. This atmospheric <span class="hlt">dust</span> is one of the main driving forces of the present Martian climate. The Story Vrrrrooooooooom. Think of a tornado, the cartoon Tasmanian devil, or any number of vacuum commercials that powerfully suck up swirls of <span class="hlt">dust</span> and dirt. That's pretty much what it's like on the surface of Mars a lot of the time. Whirlpools of wind called</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24532209','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24532209"><span>Will urban expansion <span class="hlt">lead</span> to an increase in future water pollution <span class="hlt">loads</span>?--a preliminary investigation of the Haihe River Basin in northeastern China.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dong, Yang; Liu, Yi; Chen, Jining</p> <p>2014-01-01</p> <p>Urban expansion is a major driving force changing regional hydrology and nonpoint source pollution. The Haihe River Basin, the political, economic, and cultural center of northeastern China, has undergone rapid urbanization in recent decades. To investigate the consequences of future urban sprawl on nonpoint source water pollutant emissions in the river basin, the urban sprawl in 2030 was estimated, and the annual runoff and nonpoint source pollution in the Haihe River basin were simulated. The Integrated Model of Non-Point Sources Pollution Processes (IMPULSE) was used to simulate the effects of urban sprawl on nonpoint source pollution emissions. The outcomes indicated that the urban expansion through 2030 increased the nonpoint source total nitrogen (TN), total phosphorous (TP), and chemical oxygen demand (COD) emissions by 8.08, 0.14, and 149.57 kg/km(2), respectively. Compared to 2008, the total nonpoint emissions rose by 15.33, 0.57, and 12.39 %, respectively. Twelve percent of the 25 cities in the basin would increase by more than 50 % in nonpoint source TN and COD emissions in 2030. In particular, the nonpoint source TN emissions in Xinxiang, Jiaozuo, and Puyang would rise by 73.31, 67.25, and 58.61 %, and the nonpoint source COD emissions in these cities would rise by 74.02, 51.99, and 53.27 %, respectively. The point source pollution emissions in 2008 and 2030 were also estimated to explore the effects of urban sprawl on total water pollution <span class="hlt">loads</span>. Urban sprawl through 2030 would bring significant structural changes of total TN, TP, and COD emissions for each city in the area. The results of this study could provide insights into the effects of urbanization in the study area and the methods could help to recognize the role that future urban sprawl plays in the total water pollution <span class="hlt">loads</span> in the water quality management process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5344033','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5344033"><span>Multimedia Exposures to Arsenic and <span class="hlt">Lead</span> for Children Near an Inactive Mine Tailings and Smelter Site</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Loh, Miranda M.; Sugeng, Anastasia; Lothrop, Nathan; Klimecki, Walter; Cox, Melissa; Wilkinson, Sarah T.; Lu, Zhenqiang; Beamer, Paloma I.</p> <p>2016-01-01</p> <p>Children living near contaminated mining waste areas may have high exposures to metals from the environment. This study investigates whether exposure to arsenic and <span class="hlt">lead</span> is higher in children in a community near a legacy mine and smelter site in Arizona compared to children in other parts of the United States and the relationship of that exposure to the site. Arsenic and <span class="hlt">lead</span> were measured in residential soil, house <span class="hlt">dust</span>, tap water, urine, and toenail samples from 70 children in 34 households up to 7 miles from the site. Soil and house <span class="hlt">dust</span> were sieved, digested, and analyzed via ICP-MS. Tap water and urine were analyzed without digestion, while toenails were washed, digested and analyzed. Blood <span class="hlt">lead</span> was analyzed by an independent, certified laboratory. Spearman correlation coefficients were calculated between each environmental media and urine and toenails for arsenic and <span class="hlt">lead</span>. Geometric mean arsenic (standard deviation) concentrations for each matrix were: 22.1 (2.59) ppm and 12.4 (2.27) ppm for soil and house <span class="hlt">dust</span> (<63 μm), 5.71 (6.55) ppb for tap water, 14.0 (2.01) μg/L for specific gravity-corrected total urinary arsenic, 0.543 (3.22) ppm for toenails. Soil and vacuumed <span class="hlt">dust</span> <span class="hlt">lead</span> concentrations were 16.9 (2.03) ppm and 21.6 (1.90) ppm. The majority of blood <span class="hlt">lead</span> levels were below the limit of quantification. Arsenic and <span class="hlt">lead</span> concentrations in soil and house <span class="hlt">dust</span> decreased with distance from the site. Concentrations in soil, house <span class="hlt">dust</span>, tap water, along with floor <span class="hlt">dust</span> <span class="hlt">loading</span> were significantly associated with toenail and urinary arsenic but not <span class="hlt">lead</span>. Mixed models showed that soil and tap water best predicted urinary arsenic. In our study, despite being present in mine tailings at similar levels, internal <span class="hlt">lead</span> exposure was not high, but arsenic exposure was of concern, particularly from soil and tap water. Naturally occurring sources may be an additional important contributor to exposures in certain legacy mining areas. PMID:26803211</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26803211','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26803211"><span>Multimedia exposures to arsenic and <span class="hlt">lead</span> for children near an inactive mine tailings and smelter site.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Loh, Miranda M; Sugeng, Anastasia; Lothrop, Nathan; Klimecki, Walter; Cox, Melissa; Wilkinson, Sarah T; Lu, Zhenqiang; Beamer, Paloma I</p> <p>2016-04-01</p> <p>Children living near contaminated mining waste areas may have high exposures to metals from the environment. This study investigates whether exposure to arsenic and <span class="hlt">lead</span> is higher in children in a community near a legacy mine and smelter site in Arizona compared to children in other parts of the United States and the relationship of that exposure to the site. Arsenic and <span class="hlt">lead</span> were measured in residential soil, house <span class="hlt">dust</span>, tap water, urine, and toenail samples from 70 children in 34 households up to 7 miles from the site. Soil and house <span class="hlt">dust</span> were sieved, digested, and analyzed via ICP-MS. Tap water and urine were analyzed without digestion, while toenails were washed, digested and analyzed. Blood <span class="hlt">lead</span> was analyzed by an independent, certified laboratory. Spearman correlation coefficients were calculated between each environmental media and urine and toenails for arsenic and <span class="hlt">lead</span>. Geometric mean arsenic (standard deviation) concentrations for each matrix were: 22.1 (2.59) ppm and 12.4 (2.27)ppm for soil and house <span class="hlt">dust</span> (<63μm), 5.71 (6.55)ppb for tap water, 14.0 (2.01)μg/L for specific gravity-corrected total urinary arsenic, 0.543 (3.22)ppm for toenails. Soil and vacuumed <span class="hlt">dust</span> <span class="hlt">lead</span> concentrations were 16.9 (2.03)ppm and 21.6 (1.90) ppm. The majority of blood <span class="hlt">lead</span> levels were below the limit of quantification. Arsenic and <span class="hlt">lead</span> concentrations in soil and house <span class="hlt">dust</span> decreased with distance from the site. Concentrations in soil, house <span class="hlt">dust</span>, tap water, along with floor <span class="hlt">dust</span> <span class="hlt">loading</span> were significantly associated with toenail and urinary arsenic but not <span class="hlt">lead</span>. Mixed models showed that soil and tap water best predicted urinary arsenic. In our study, despite being present in mine tailings at similar levels, internal <span class="hlt">lead</span> exposure was not high, but arsenic exposure was of concern, particularly from soil and tap water. Naturally occurring sources may be an additional important contributor to exposures in certain legacy mining areas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011APS..DFDL14006F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011APS..DFDL14006F"><span>MLM: <span class="hlt">Dust</span> Explosion Potential Warning System</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Foss, John; Lawrenz, Alan</p> <p>2011-11-01</p> <p>A quite large range of materials, when dispersed as a <span class="hlt">dust</span> cloud in air, can support an explosion. Empirically derived minimum explosive concentration (MEC) values are typically in the range: 30-80 grams/m3; that is, nominally 2.5-8.3% of STP density. Currently, there is no field-deployable measurement system to determine the mass <span class="hlt">loading</span> (grams/m3) of airborne <span class="hlt">dust</span>. Proof-of-concept measurements for the MSU Mass <span class="hlt">Loading</span> Monitor (MLM) are reported. A charge of dusty air, ingested into a cylinder, is accelerated (ap=ct) by a driving piston and partially (~8%) discharged from the open end of the cylinder. The deformable control volume momentum equation can be integrated with respect to time to yield α() -β() = γρ() where () will indicate with (w) or without (w/o) <span class="hlt">dust</span>. The pressure integral (α) and the shear integral (β) balance the momentum within the cylinder at the end of the smoke plus the integral of the momentum flux. The kinematic attributes of these terms are represented by γ. It will be shown how the mass <span class="hlt">loading</span> (ρw -ρw / o) can be determined. A full length paper (The Mass <span class="hlt">Loading</span> Monitor Fundamental Principles And Proof Of Concept) will be published in Meas. Sci. and Tech.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.A41L..01K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.A41L..01K"><span>Source characterization and trend analysis of the Sahelian <span class="hlt">dust</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, D.; Chin, M.; Diehl, T. L.</p> <p>2012-12-01</p> <p><span class="hlt">Dust</span> has significant impacts on human health and the economy, specifically over the Sahel, which is the semi-arid region located south of the Sahara desert. Also, the region is highly vulnerable to future climate changes and especially to a drier and windier climate. Estimating the impact of the Sahelian <span class="hlt">dust</span> on the local and extended area is complicated because the Sahel itself is an active <span class="hlt">dust</span> source region and it is located downwind of the Sahara, including the Bodélé depression. A previous study estimated that emissions driven by strong surface winds occurring across the Sahel significantly contribute to the total <span class="hlt">dust</span> <span class="hlt">load</span> over West and North Africa. Another previous study using the ERA-Interim-Reanalysis data concluded that <span class="hlt">dust</span> emission from the Sahara and subsequent transport of the <span class="hlt">dust</span> to the Sahel driven by the synoptic patterns is mainly responsible for the formation of the Sahel <span class="hlt">dust</span> zone. <span class="hlt">Dust</span> generation in the Sahel is also related to precipitation and human activity. The long-term trend of the Sahelian desert and <span class="hlt">dust</span> varies depending on analysis methods and periods, and the analyses show either an increasing trend, little change, or a decreasing trend. There is a large gap in models handling the Sahelian <span class="hlt">dust</span>. A recent review on global <span class="hlt">dust</span> sources and emission rates indicated that most models do not include emissions from the Sahel. We will present the result of a modeling study on the Sahelian <span class="hlt">dust</span> using the NASA GOCART model. The <span class="hlt">dust</span> parameterization has been recently updated with the dynamic source function that utilizes the satellite observed Normalized Difference Vegetation Index. The meteorological fields are taken from the latest version of the NASA GEOS5 system. These recent improvements enable the model to perform more realistic simulations of the Sahelian <span class="hlt">dust</span>, which has a strong seasonal variation. Specifically our focus in this study is two folds. First, we will attribute the source of <span class="hlt">dust</span> between the locally emitted <span class="hlt">dust</span> and the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3988900','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3988900"><span>Are Providers More Likely to Contribute to Healthcare Disparities Under High Levels of Cognitive <span class="hlt">Load</span>? How Features of the Healthcare Setting May <span class="hlt">Lead</span> to Biases in Medical Decision Making</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Burgess, Diana J.</p> <p>2014-01-01</p> <p>Systematic reviews of healthcare disparities suggest that clinicians’ diagnostic and therapeutic decision making varies by clinically irrelevant characteristics, such as patient race, and that this variation may contribute to healthcare disparities. However, there is little understanding of the particular features of the healthcare setting under which clinicians are most likely to be inappropriately influenced by these characteristics. This study delineates several hypotheses to stimulate future research in this area. It is posited that healthcare settings in which providers experience high levels of cognitive <span class="hlt">load</span> will increase the likelihood of racial disparities via 2 pathways. First, providers who experience higher levels of cognitive <span class="hlt">load</span> are hypothesized to make poorer medical decisions and provide poorer care for all patients, due to lower levels of controlled processing (H1). Second, under greater levels of cognitive <span class="hlt">load</span>, it is hypothesized that healthcare providers’ medical decisions and interpersonal behaviors will be more likely to be influenced by racial stereotypes, <span class="hlt">leading</span> to poorer processes and outcomes of care for racial minority patients (H2). It is further hypothesized that certain characteristics of healthcare settings will result in higher levels of cognitive <span class="hlt">load</span> experienced by providers (H3). Finally, it is hypothesized that minority patients will be disproportionately likely to be treated in healthcare settings in which providers experience greater levels of cognitive <span class="hlt">load</span> (H4a), which will result in racial disparities due to lower levels of controlled processing by providers (H4b) and the influence of racial stereotypes (H4c).The study concludes with implications for research and practice that flow from this framework. PMID:19726783</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AeoRe..24..145R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AeoRe..24..145R"><span>Assessment of <span class="hlt">dust</span> activity and <span class="hlt">dust</span>-plume pathways over Jazmurian Basin, southeast Iran</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rashki, A.; Arjmand, M.; Kaskaoutis, D. G.</p> <p>2017-02-01</p> <p>Jazmurian (or hamun-e Jaz Murian) is a dried lake located in a topographic-low basin in southeast Iran and a major source for high <span class="hlt">dust</span> emissions under favorable weather conditions. This work examines for the first time the <span class="hlt">dust</span> activity over the basin by classifying the <span class="hlt">dust</span> events (DEs, visibility <10 km) and <span class="hlt">dust</span>-storm events (DSEs, visibility <1 km) based on observations at five local meteorological stations during the period 1990-2013. Analysis of the temporal evolution, seasonality, frequency and persistence (duration) of the DEs and DSEs, along with examination of the backward and forward air-mass trajectories in the Jazmurian Basin are the main objectives of the present study. The DEs exhibit maximum frequency in June-July and lowest in autumn and winter, while the DSEs peak mostly during March-May also presenting large variability between the stations. The frequency of both the DEs and DSEs increases during ∼2001-2004 due to a prolonged drought over southeastern Iran, while no significant tendency is found during the period 1990-2013. Further, the DEs and DSEs exhibit a clear diurnal pattern with highest frequency between 15:30 and 18:30 LST due to thermal convection and transported <span class="hlt">dust</span> plumes. The analysis reveals an average frequency of 12.7 <span class="hlt">dust</span>-storm days per year, while the DSEs last for 5.1 h, on average, during the <span class="hlt">dust</span>-storm days. The <span class="hlt">dust</span> storms originating from Jazmurian affect mostly the northern coast of the Arabian Sea (Makran mountains), the Oman Sea, the southeastern Arabian Peninsula and the western Pakistan, while air masses from the arid/desert areas of central-eastern Iran and Arabia seem to further aggravate the <span class="hlt">dust</span>-aerosol <span class="hlt">loading</span> over Jazmurian.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010DPS....42.2827L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010DPS....42.2827L"><span>Whither Cometary <span class="hlt">Dust</span>?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lisse, Carey M.</p> <p>2010-10-01</p> <p>In this paper I will discuss recent findings that have important implications for our understanding of the formation and evolution of primitive solar system <span class="hlt">dust</span>, including: - Nesvorny et al. (2010), following up on their dynamical analyses of the zodiacal <span class="hlt">dust</span> bands as sourced by the breakup of the Karin (5Mya) and Veritas (8Mya) asteroid families, argue that over 90% of the interplanetary <span class="hlt">dust</span> cloud at 1 AU comes from JFC comets with near-circularized, low inclination orbits. This implies that the noted IPD collections of anhydrous and hydrous <span class="hlt">dust</span> particles are likely to be from Oort cloud and JFC comets, respectively, not from asteroids and comets as thought in the past. Hydrous <span class="hlt">dust</span> particles from comets like 85P/Wild2 and 9P/Tempel 1 would be consistent with results from the STARDUST and Deep Impact experiments. - Estimates of the <span class="hlt">dust</span> particle size distributions (PSDs) in the comae of 85P/Wild2 (Green et al. 2004, 2007) and 73P/SW-3 (Sitko et al. 2010, Vaubaillon & Reach 2010) and in the trails of comets (Reach et al. 2007) have broken power law structure, with a plateau enhancement of particles of 1 mm - 1 cm in size. This size is also the size of most chondritic inclusions, and the predicted size range of the "aggregational barrier", where collisions between <span class="hlt">dust</span> particles become destructive. - Studies of the albedo and polarization properties of cometary <span class="hlt">dust</span> (Kolokolova et al. 2007) suggest there are 2 major groupings, one with low scattering capability and one with high. While these families could possibly have been explained by systematics in the PSDs of the emitted <span class="hlt">dust</span>, independent work by Lisse et al. (2008) on the mineralogy of a number of highly dusty comets has shown evidence for one family of comets with highly crystalline <span class="hlt">dust</span> and another with highly amorphous <span class="hlt">dust</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003JGRD..108.8596C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003JGRD..108.8596C"><span>Estimation of diurnal shortwave <span class="hlt">dust</span> aerosol radiative forcing during PRIDE</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Christopher, Sundar A.; Wang, Jun; Ji, Qiang; Tsay, Si-Chee</p> <p>2003-10-01</p> <p>Using measured and derived aerosol properties from the Puerto Rico <span class="hlt">Dust</span> Experiment (PRIDE), a four-stream broadband radiative transfer model is used to calculate the downward shortwave irradiance (DSWI) at the surface and the shortwave irradiance at the top of atmosphere (TOA). The results of the calculated DSWI are compared against pyranometer measurements from the Surface Measurements For Atmospheric Radiative Transfer (SMART) instrument suite at Roosevelt Road (18.20°N, 65.60°W). Using aerosol optical thickness retrievals from half-hourly geostationary satellite data (GOES 8 imager), the diurnal short wave aerosol forcing (SWARF) of <span class="hlt">dust</span> aerosols both at the surface and TOA are calculated for the entire study area (14°N ˜ 26°N, 61°W ˜ 73°W). For selected days, the Clouds and the Earth Radiant Energy System (CERES) TOA shortwave irradiance values from Terra are compared with radiative transfer calculations. [2003] show that the satellite derived aerosol optical thickness is in excellent agreement with Aerosol Robotic Network (AERONET) values. Results of this study show that the calculated direct, diffuse and total DSWI are in excellent agreement with the corresponding SMART values with biases of 1.8%, -3.3% and 0.5% respectively, indicating that <span class="hlt">dust</span> aerosols are well characterized in the radiative transfer model. This is well within the measured uncertainties (1.3%) and the model uncertainties (5%). The monthly mean value and standard deviation of aerosol optical thickness at 670 nm (AOT670) during PRIDE are 0.26 ± 0.13, and the corresponding monthly mean daytime SWARF values are -12.34 ± 9.62 W m-2 at TOA and -18.13 ± 15.81 W m-2 at the surface, respectively. Our results also show that if diurnal changes in aerosol optical thickness are not considered, it <span class="hlt">leads</span> to uncertainties in SWARF of 4 W m-2 at the surface and 2 W m-2 at the TOA. The CERES TOA short wave irradiance underestimates calculated values by about 10 W m-2 mainly due problems in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/a