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Sample records for wet deposition temporal

  1. 1987 wet deposition temporal and spatial patterns in North America

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, J.C.; Olsen, A.R.

    1990-03-01

    The focus of this report is on North American wet deposition temporal patterns from 1979 to 1987 and spatial patterns for 1987. The report investigates the patterns of annual precipitation-weighted average concentration and annual deposition for nine ion species: hydrogen, sulfate, nitrate, ammonium, calcium, chloride, sodium, potassium, and magnesium. Data are from the Acid Deposition System (ADS) for the statistical reporting of North American deposition data which includes the National Atmospheric Deposition Program/National Trends Network (NADP/NTN), the MAP3S precipitation chemistry network, the Utility Acid Precipitation Study Program (UAPSP), the Canadian Precipitation Monitoring Network (CAPMoN), and the daily and 4-weekly Acidic Precipitation in Ontario Study (APIOS-D and APIOS-C). Mosaic maps, based on surface estimation using kriging, display concentration and deposition spatial patterns of pH, hydrogen, sulfate, nitrate, ammonium, and calcium ion species for 1987 annual, winter, and summer periods. The temporal pattern analyses use a subset of 39 sites over a 9-year (1979--1987) period and an expanded subset of 140 sites with greater spatial coverage over a 6-year (1982--1987) period. 68 refs., 15 figs., 15 tabs.

  2. Modeled Wet Nitrate Deposition

    Data.gov (United States)

    U.S. Environmental Protection Agency — Modeled data on nitrate wet deposition was obtained from Dr. Jeff Grimm at Penn State Univ. Nitrate wet depostion causes acidification and eutrophication of surface...

  3. Temporal trajectories of wet deposition across hydro-climatic regimes: Role of urbanization and regulations at U.S. and East Asia sites

    Science.gov (United States)

    Park, Jeryang; Gall, Heather E.; Niyogi, Dev; Rao, P. Suresh C.

    2013-05-01

    Dominant global patterns of urbanization and industrialization contribute to large-scale modification of the drivers for hydrologic and biogeochemical processes, as evident in Asia, Africa, and South America which are experiencing rapid population and economic growth. One manifestation of urbanization and economic development is decreases in air quality, increases in dry/wet deposition fluxes, and growing adverse impacts on public health and ecosystem integrity. We examined available long-term (1980-2010) observational data, gathered at weekly intervals, for wet deposition at 19 urban sites in the U.S., and monitoring data (2000-2009) available for 17 urban sites at a monthly scale in East Asia. Our analyses are based on data for four constituents (SO42-, NO3-, Ca2+, and Mg2+); differences in atmospheric chemistry and terrestrial sources of these constituents enabled a robust comparative analysis. We examined intra-annual variability and the long-term temporal trajectories of wet deposition fluxes to discern the relative role of anthropogenic and stochastic hydro-climatic forcing. Here, we show that: (1) temporal variability in wet deposition fluxes follows an exponential probability density function at all sites, evidence that stochasticity of rainfall is the dominant control of wet deposition variability; (2) the mean wet deposition flux, μΩ (ML-2T-1), has decreased in the U.S. over time since enactment of the Clean Air Act, with μΩ having become homogenized across varying hydro-climatic regimes; and (3) in contrast, μΩ values for East Asian cities are 3-10 times higher than U.S. cities, attributed to lax regulatory enforcement. Based on the observed patterns, we suggest a stochastic model that generates ellipses within which the μΩ temporal trajectories are inscribed. In the U.S., anthropogenic forcing (regulations) is dominant in the humid regions, while variability in hydro-climatic forcing explains inter-annual variability in arid regions. Our

  4. European wet deposition maps based on measurements

    NARCIS (Netherlands)

    Leeuwen EP van; Erisman JW; Draaijers GPJ; Potma CJM; Pul WAJ van; LLO

    1995-01-01

    To date, wet deposition maps on a European scale have been based on long-range transport model results. For most components wet deposition maps based on measurements are only available on national scales. Wet deposition maps of acidifying components and base cations based on measurements are needed

  5. Spatial and temporal variability of (7)Be and (210)Pb wet deposition during four successive monsoon storms in a catchment of northern Laos.

    Science.gov (United States)

    Gourdin, E; Evrard, O; Huon, S; Reyss, J-L; Ribolzi, O; Bariac, T; Sengtaheuanghoung, O; Ayrault, S

    2014-10-01

    Fallout radionuclides (7)Be and (210)Pb have been identified as potentially relevant temporal tracers for studying soil particles dynamics (surface vs. subsurface sources contribution; remobilization of in-channel sediment) during erosive events in river catchments. An increasing number of studies compared (7)Be: (210)Pb activity ratio in rainwater and sediment to estimate percentages of freshly eroded particles. However, the lack of data regarding the spatial and temporal variability of radionuclide wet deposition during individual storms has been identified as one of the main gaps in these estimates. In order to determine these key parameters, rainwater samples were collected at three stations during four storms that occurred at the beginning of the monsoon (June 2013) in the Houay Xon mountainous catchment in northern Laos. Rainwater (7)Be and (210)Pb activities measured using very low background hyperpure Germanium detectors ranged from 0.05 to 1.72 Bq L(-1) and 0.02 to 0.26 Bq L(-1), respectively. Water δ(18)O were determined on the same samples. Total rainfall amount of the four sampled storms ranged from 4.8 to 26.4 mm (51 mm in total) at the time-fractionated collection point. Corresponding cumulative (7)Be and (210)Pb wet depositions during the sampling period were 17.6 and 2.9 Bq m(-2), respectively. The (7)Be: (210)Pb activity ratio varied (1) in space from 6 to 9 for daily deposition and (2) in time from 3 to 12 for samples successively collected. Intra-event evolution of rainwater (7)Be and (210)Pb activities as well as δ(18)O highlighted the progressive depletion of local infra-cloud atmosphere radionuclide stock with time (washout), which remains consistent with a Raleigh-type distillation process for water vapour. Intra-storm ratio increasing with time showed the increasing contribution of rainout scavenging. Implications of such variability for soil particle labelling and erosion studies are briefly discussed and recommendations are formulated

  6. ROE Wet Nitrate Deposition 2011-2013

    Data.gov (United States)

    U.S. Environmental Protection Agency — The raster data represent the amount of wet nitrate deposition in kilograms per hectare from 2011 to 2013. Summary data in this indicator were provided by EPA’s...

  7. ROE Wet Nitrate Deposition 1989-1991

    Data.gov (United States)

    U.S. Environmental Protection Agency — The raster data represent the amount of wet nitrate deposition in kilograms per hectare from 1989 to 1991. Summary data in this indicator were provided by EPA’s...

  8. ROE Wet Sulfate Deposition 2009-2011

    Data.gov (United States)

    U.S. Environmental Protection Agency — The raster data represent the amount of wet sulfate deposition in kilograms per hectare from 2009 to 2011. Summary data in this indicator were provided by EPA’s...

  9. Wet Deposition Concentrations and Fluxes of Mercury in Taiwan

    Science.gov (United States)

    Sheu, G.; Lin, N.

    2010-12-01

    Taiwan is located downwind to the largest anthropogenic Hg emission source region, the East Asian continent, and thus model simulations often predicted that Taiwan could receive high Hg input via wet deposition. Therefore, a mercury (Hg) wet deposition monitoring network was established in Taiwan to collect rainwater for total Hg analysis since September 2008. The objective of this network is to establish a national database of wet deposition concentrations and fluxes of Hg. This database will later be used to develop information on spatial and temporal trends in Hg wet deposition and to evaluate the contribution of regional/long-range transport. A total of 12 sampling sites, covering urban, rural, mountain, coastal and remote island areas, were set up. Weekly samples were collected using automated wet-only precipitation collection systems. Acid-cleaned glass funnels were used for rainwater collections and samples were collected into acid-cleaned 1L Teflon bottles. Samples were retrieved and sampling trains were changed every Tuesday morning. Total Hg was quantified by dual amalgamation CVAFS after BrCl oxidation, NH2OH●HCl neutralization, and SnCl2 reduction. In 2009, total Hg concentrations of all the rainwater samples ranged from 2.1 to 82.2 ng/L. Volume-weighted mean (VWM) total Hg concentrations of all the sampling sites ranged between 7.6 and 17.2 ng/L. In general, rainwater Hg concentrations were lower in northern Taiwan sites, likely due to the dilution effect caused by higher rainfall amount. Annual wet depositional Hg fluxes ranged between 12.3 and 37.0 μg/m2 in 2009, with higher values usually observed in northern Taiwan sites. The geographical distribution of wet depositional Hg flux mimicked the distribution of accumulative rainfall amount, suggesting precipitation depth is the primary factor in determining the magnitude of wet depositional Hg flux.

  10. Removal of atmospheric ethanol by wet deposition

    Science.gov (United States)

    Felix, J. David; Willey, Joan D.; Thomas, Rachel K.; Mullaugh, Katherine M.; Avery, G. Brooks; Kieber, Robert J.; Mead, Ralph N.; Helms, John; Giubbina, Fernanda F.; Campos, M. Lucia A. M.; Cala, John

    2017-02-01

    The global wet deposition flux of ethanol is estimated to be 2.4 ± 1.6 Tg/yr with a conservative range of 0.2-4.6 Tg/yr based upon analyses of 219 wet deposition samples collected at 12 locations globally. This estimate calculated by using observed wet deposition ethanol concentrations is in agreement with previous models (1.4-5 Tg/yr) predicting the wet deposition sink using Henry's law coefficients and atmospheric ethanol concentrations. Wet deposition is estimated to remove between 6 and 17% of the total ethanol emitted to the atmosphere on an annual basis. The concentration of ethanol in marine rain (25 ± 6 nM) is an order of magnitude less than in the majority of terrestrial rains (345 ± 280 nM). Terrestrial rain samples collected in locations impacted by high local sources of biofuel usage and locations downwind from ethanol distilleries were an order of magnitude higher in ethanol concentration (3090 ± 448 nM) compared to rain collected in terrestrial locations not impacted by these sources. These results indicate that wet deposition of ethanol is heavily influenced by local sources. Results of this study are important because they suggest that as biofuel production and usage increase, the concentration of ethanol in the atmosphere will increase as well the wet deposition flux. Additional research constraining the sources, sinks, and atmospheric impacts of ethanol is necessary to better assist in the debate as whether or not to increase consumption of the alcohol as a biofuel.

  11. Changes in wet nitrogen deposition in the United States between 1985 and 2012

    NARCIS (Netherlands)

    Du, E.; Vries, de W.; Galloway, J.N.; Hu, X.; Fang, J.

    2014-01-01

    The United States (US) is among the global hotspots of nitrogen (N) deposition and assessing the temporal trends of wet N deposition is relevant to quantify the effectiveness of existing N regulation policies and its consequent environmental effects. This study analyzed changes in observed wet

  12. Electrophoretic deposition of titania nanoparticles: Wet density of ...

    Indian Academy of Sciences (India)

    Administrator

    Abstract. Electrophoretic deposition (EPD) of titania nanoparticles was performed at different voltages and times. The wet density of deposits was calculated according to the Archimedes' principle. The wet density as well as the electric field over the deposits increased with time and attained the plateau at longer times. The.

  13. Electrophoretic deposition of titania nanoparticles: Wet density of ...

    Indian Academy of Sciences (India)

    Electrophoretic deposition (EPD) of titania nanoparticles was performed at different voltages and times. The wet density of deposits was calculated according to the Archimedes' principle. The wet density as well as the electric field over the deposits increased with time and attained the plateau at longer times. The velocity at ...

  14. Evaluation of the Acidic Wet Deposition Predictions of CMAQ

    Science.gov (United States)

    Dennis, R. L.

    2002-05-01

    Acidic deposition is coming back into importance as part of more encompassing multi-pollutant thinking. Acidic and nutrient deposition is an important component of new multi-pollutant legislation being considered by the Administration. The Community Multiscale Air Quality model, CMAQ, was designed to handle multiple pollutants in a one-atmosphere context. Much of the initial evaluation of CMAQ was directed at the criteria pollutants. CMAQ's predictions of acidic deposition also need to be evaluated, not only because of the importance of deposition but also because deposition sets the lifetime of fine particles in the atmosphere. The controlling deposition is wet deposition, hence, we consider it first. We compare wet deposition for selected months throughout 1990, showing that CMAQ captures the main features of seasonality. We note that the previous problem of overprediction of winter wet deposition associated with the RADM cloud parameterization has been addressed through explicit recognition of icy cloud water. We are still plagued by the difficulty of meteorological models to predict precipitation as input to chemical transport models which produces additional scatter. Interestingly, there is a consistent differential between sulfate and nitrate wet deposition, with nitrate wet deposition being slightly lower. We explore several hypotheses for this behavior, including the hypothesis that this is more an issue of mixing than an issue of cloud chemistry. In general, CMAQ appears to be producing reasonable predictions that demonstrate an improvement in our ability to predict wet deposition, although there is room for improvement.

  15. Spatial and temporal variations in the occurrences of wet periods ...

    Indian Academy of Sciences (India)

    This study highlights the hydro-climatic features of the five wet periods contributing in different percentages to the annual rainfall total over major river basins in India. Spatial and temporal variations in the parameters such as starting date, duration and rainfall intensity of these wet periods throughout India have been ...

  16. Spatial and temporal variations in the occurrences of wet periods ...

    Indian Academy of Sciences (India)

    This study highlights the hydro-climatic features of the five wet periods contributing in different percentages to the annual rainfall total over major river basins in India.Spatial and temporal variations in the parameters such as starting date,duration and rainfall intensity of these wet periods throughout India have been ...

  17. ROE Wet Sulfate Deposition Raster 1989-1991

    Data.gov (United States)

    U.S. Environmental Protection Agency — The raster data represent the amount of wet sulfate deposition in kilograms per hectare from 1989 to 1991. Summary data in this indicator were provided by EPA’s...

  18. [Characteristics of atmospheric nitrogen wet deposition in Beijing urban area].

    Science.gov (United States)

    He, Cheng-Wu; Ren, Yu-Fen; Wang, Xiao-Ke; Mao, Yu-Xiang

    2014-02-01

    With the ion-exchange resin method, the atmospheric nitrogen wet deposition in Beijing urban area within the Fifth Ring Road was investigated from June to October, 2012. The relationship between atmospheric nitrogen wet deposition and rainfall precipitation was investigated, the differences of nitrogen wet deposition in different months, different ring roads (the Fifth Ring Road, the Fourth Ring Road, the Third Ring Road and the Second Ring Road) and different functional areas (institutes and colleges district, ring-road, residential areas, railway station and public garden) were also investigated. The results showed that the average value and standard deviation of ammonia-nitrogen, nitrate-nitrogen and nitrite-nitrogen were significantly different during different months in 2012. The atmospheric nitrite nitrogen deposition first decreased and then increased, the maximum value appeared in September. The positive relationships between ammonia nitrogen (nitrate nitrogen) and mean monthly precipitation and negative relationships between nitrite nitrogen and mean monthly precipitation were both significant (P functional areas, but only the nitrite nitrogen deposition had obvious regional difference. The differences of the three nitrogen depositions among different ring roads were all not significant and it meant that the nitrogen wet deposition was equally distributed in Beijing urban area.

  19. Atmospheric wet and dry deposition of trace elements at ten sites in Northern China

    Science.gov (United States)

    Pan, Y. P.; Wang, Y. S.

    2014-08-01

    Atmospheric deposition is considered to be a major process that removes pollutants from the atmosphere and an important source of nutrients and contaminants for ecosystems. Trace elements (TEs), especially toxic metals deposited on plants and into soil and water, can cause substantial damage to the environment and human health due to their transfer and accumulation in food chains. Despite public concerns, quantitative knowledge of metal deposition from the atmosphere to ecosystems remains scarce. To advance our understanding of the spatio-temporal variations in the magnitudes, pathways, compositions and impacts of atmospherically deposited TEs, precipitation (rain and snow) and dry-deposited particles were collected simultaneously at ten sites in Northern China from December 2007 to November 2010. The measurements showed that the wet and dry depositions of TEs in the target areas were orders of magnitude higher than previous observations within and outside China, generating great concern over the potential risks. The spatial distribution of the total (wet plus dry) deposition flux was consistent with that of the dry deposition, with a significant decrease from industrial and urban areas to suburban, agricultural and rural sites. In contrast, the wet deposition exhibited less spatial variation. The seasonal variation of wet deposition was also different from that of dry deposition, although they were both governed by the precipitation and emission patterns. For the majority of TEs that exist as coarse particles, dry deposition dominated the total flux at each site. This was not the case for K, Ni, As, Pb, Zn, Cd, Se, Ag and Tl, for which the relative importance between wet and dry deposition fluxes varied by site. Whether wet deposition is the major atmospheric cleansing mechanism for the TEs depends on the size distribution and solubility of the particles. We found that atmospheric inputs of Cu, Pb, Zn, Cd, As and Se were of the same magnitude as their increases in

  20. Atmospheric wet and litterfall mercury deposition at urban and rural sites in China

    Directory of Open Access Journals (Sweden)

    X. Fu

    2016-09-01

    Full Text Available Mercury (Hg concentrations and deposition fluxes in precipitation and litterfall were measured at multiple sites (six rural sites and an urban site across a broad geographic area in China. The annual deposition fluxes of Hg in precipitation at rural sites and an urban site were 2.0 to 7.2 and 12.6 ± 6.5 µg m−2 yr−1, respectively. Wet deposition fluxes of Hg at rural sites showed a clear regional difference with elevated deposition fluxes in the subtropical zone, followed by the temporal zone and arid/semi-arid zone. Precipitation depth is the primary influencing factor causing the variation of wet deposition. Hg fluxes through litterfall ranged from 22.8 to 62.8 µg m−2 yr−1, higher than the wet deposition fluxes by a factor of 3.9 to 8.7 and representing approximately 75 % of the total Hg deposition at the forest sites in China. This suggests that uptake of atmospheric Hg by foliage is the dominant pathway to remove atmospheric Hg in forest ecosystems in China. Wet deposition fluxes of Hg at rural sites of China were generally lower compared to those in North America and Europe, possibly due to a combination of lower precipitation depth, lower GOM concentrations in the troposphere and the generally lower cloud base heights at most sites that wash out a smaller amount of GOM and PBM during precipitation events.

  1. Wet deposition of poly- and perfluorinated compounds in Northern Germany

    Energy Technology Data Exchange (ETDEWEB)

    Dreyer, Annekatrin, E-mail: annekatrin.dreyer@gkss.d [GKSS Research Centre, Institute for Coastal Research, Max Planck Str. 1, 21502 Geesthacht (Germany); Matthias, Volker; Weinberg, Ingo; Ebinghaus, Ralf [GKSS Research Centre, Institute for Coastal Research, Max Planck Str. 1, 21502 Geesthacht (Germany)

    2010-05-15

    Twenty precipitation samples were taken concurrently with air samples at a northern German monitoring site over a period of 7 months in 2007 and 2008. Thirty four poly- and perfluorinated compounds (PFC) were determined in rain water samples by solid phase extraction and HPLC-MS/MS analysis. Seventeen compounds were detected in rain water with SIGMAPFC concentrations ranging from 1.6 ng L{sup -1} to 48.6 ng L{sup -1}. Perfluorooctanoate (PFOA) and perfluorobutanate (PFBA) were the compounds that were usually observed in highest concentrations. Calculated SIGMAPFC deposition rates were between 2 and 91 ng m{sup -2} d{sup -1}. These findings indicate that particle phase PFC are deposited from the atmosphere by precipitation. A relationship between PFC wet deposition and air concentration may be established via precipitation amounts. Trajectory analysis revealed that PFC concentration and deposition estimates in precipitation can only be explained if a detailed air mass history is considered. - Information on air mass history, meteorological conditions, and distribution of PFC sources is necessary to understand and estimate PFC concentrations and wet deposition.

  2. Rates of Dry Deposition Determined Using Wet/Dry Collectors

    Science.gov (United States)

    Feely, H. W.; Bogen, D. C.; Nagourney, S. J.; Torquato, C. C.

    1985-02-01

    Daily samples of dryfall were collected during the June 1982 Dry Deposition Measurement Intercomparison Study at Champaign, Illinois, using six Aerochem Metrics wet/dry collectors. Upon completion of the field experiment, these samples were analyzed at the Environmental Measurements Laboratory for pH and for their concentrations of major inorganic constituents. Contamination by rain and bird droppings rendered a number of dryfall samples unusuable. When data for these samples were removed, the remaining data displayed acceptable precision for sulfate, calcium, and magnesium. The measured deposition rates varied between 7 and 73 ng/m2/s for sulfate, between 7 and 44 for calcium, and between 0.8 and 8.1 for magnesium. The precision of the data for ammonium, nitrate, and phosphate was poor, so we have not calculated deposition rates for these constituents. The measurements of the atmospheric concentrations of sulfate reported by the Illinois State Water Survey have been used to calculate deposition velocities for particulate sulfate for 18 daily samples, even though the aerosol sampler and the dry bucket of the wet/dry collector may not sample the same size population of particulates. These velocities ranged from 0.1 to 1.2 cm/s, with a median value of 0.4 cm/s and a mean of 0.45±0.31 cm/s.

  3. 3D Modelling of Transport, Deposition and Resuspension of Highway Deposited Sediments in wet Detention Ponds

    DEFF Research Database (Denmark)

    Bentzen, Thomas Ruby

    2010-01-01

    The paper presents results from an experimental and numerical study of flows and transport of primarily particle bound pollutants in highway wet detention ponds. The study presented here is part of a general investigation on road runoff and pollution in respect to wet detention ponds. The objective...... pollutants and particles in wet detention ponds is possible with application of a three dimensional RANS model and the advection/dispersion equation taken physical phenomena like wind, waves, deposition, erosion and consolidation of the bottom sediment into account....

  4. Increasing aeolian dust deposition to snowpacks in the Rocky Mountains inferred from snowpack, wet deposition, and aerosol chemistry

    Science.gov (United States)

    Clow, David W.; Williams, Mark W.; Schuster, Paul F.

    2016-12-01

    Mountain snowpacks are a vital natural resource for ∼1.5 billion people in the northern Hemisphere, helping to meet human and ecological demand for water in excess of that provided by summer rain. Springtime warming and aeolian dust deposition accelerate snowmelt, increasing the risk of water shortages during late summer, when demand is greatest. While climate networks provide data that can be used to evaluate the effect of warming on snowpack resources, there are no established regional networks for monitoring aeolian dust deposition to snow. In this study, we test the hypothesis that chemistry of snow, wet deposition, and aerosols can be used as a surrogate for dust deposition to snow. We then analyze spatial patterns and temporal trends in inferred springtime dust deposition to snow across the Rocky Mountains, USA, for 1993-2014. Geochemical evidence, including strong correlations (r2 ≥ 0.94) between Ca2+, alkalinity, and dust concentrations in snow deposited during dust events, indicate that carbonate minerals in dust impart a strong chemical signature that can be used to track dust deposition to snow. Spatial patterns in chemistry of snow, wet deposition, and aerosols indicate that dust deposition increases from north to south in the Rocky Mountains, and temporal trends indicate that winter/spring dust deposition increased by 81% in the southern Rockies during 1993-2014. Using a multivariate modeling approach, we determined that increases in dust deposition and decreases in springtime snowfall combined to accelerate snowmelt timing in the southern Rockies by approximately 7-18 days between 1993 and 2014. Previous studies have shown that aeolian dust emissions may have doubled globally during the 20th century, possibly due to drought and land-use change. Climate projections for increased aridity in the southwestern U.S., northern Africa, and other mid-latitude regions of the northern Hemisphere suggest that aeolian dust emissions may continue to increase

  5. Trends in mercury wet deposition and mercury air concentrations across the U.S. and Canada

    Science.gov (United States)

    Weiss-Penzias, Peter S.; Gay, David A.; Brigham, Mark E.; Parsons, Matthew T.; Gustin, Mae S.; ter Shure, Arnout

    2016-01-01

    This study examined the spatial and temporal trends of mercury (Hg) in wet deposition and air concentrations in the United States (U.S.) and Canada between 1997 and 2013. Data were obtained from the National Atmospheric Deposition Program (NADP) and Environment Canada monitoring networks, and other sources. Of the 19 sites with data records from 1997–2013, 53% had significant negative trends in Hg concentration in wet deposition, while no sites had significant positive trends, which is in general agreement with earlier studies that considered NADP data up until about 2010. However, for the time period 2007–2013 (71 sites), 17% and 13% of the sites had significant positive and negative trends, respectively, and for the time period 2008–2013 (81 sites) 30% and 6% of the sites had significant positive and negative trends, respectively. Non-significant positive tendencies were also widespread. Regional trend analyses revealed significant positive trends in Hg concentration in the Rocky Mountains, Plains, and Upper Midwest regions for the recent time periods in addition to significant positive trends in Hg deposition for the continent as a whole. Sulfate concentration trends in wet deposition were negative in all regions, suggesting a lower importance of local Hg sources. The trend in gaseous elemental Hg from short-term datasets merged as one continuous record was broadly consistent with trends in Hg concentration in wet deposition, with the early time period (1998–2007) producing a significantly negative trend (− 1.5 ± 0.2% year− 1) and the recent time period (2008–2013) displaying a flat slope (− 0.3 ± 0.1% year− 1, not significant). The observed shift to more positive or less negative trends in Hg wet deposition primarily seen in the Central-Western regions is consistent with the effects of rising Hg emissions from regions outside the U.S. and Canada and the influence of long-range transport in the free troposphere.

  6. Source identification of total mercury (TM) wet deposition using a Lagrangian particle dispersion model (LPDM)

    Science.gov (United States)

    Seo, Yong-Seok; Han, Young-Ji; Holsen, Thomas M.; Choi, Eunhwa; Zoh, Kyung-Duk; Yi, Seung-Muk

    2015-03-01

    Event-based precipitation samples for total mercury (TM) were collected with a modified MIC-B sampler concurrent with atmospheric gaseous oxidized mercury (GOM) and particulate bound mercury (PBM) concentrations in Seoul, Korea from January 2006 to December 2009 to: 1) determine the seasonal variations in TM wet deposition, 2) investigate contributions of GOM and PBM scavenging to mercury wet deposition, and 3) identify source areas contributing to the high TM wet deposition using a Lagrangian particle dispersion model (LPDM). The volume-weighted mean (VWM) TM concentration was highest in winter, while the wet deposition flux was highest in summer. Multiple linear regression showed that the scavenging coefficient (SC) for GOM was much higher than the SC for PBM indicating that GOM was more effectively scavenged by wet deposition than PBM. Joint-probability LPDM (JP-LPDM) indicated that the main sources of TM wet deposition were the industrial and coastal areas in China and Japan.

  7. Assessing the Emission Sources of Atmospheric Mercury in Wet Deposition Across Illinois, USA

    Directory of Open Access Journals (Sweden)

    Gratz L. E.

    2013-04-01

    Full Text Available From August 2007 to August 2009, we collected event-based precipitation samples for mercury (Hg and trace element analysis at four sites in Illinois, USA. The objectives of these measurements were to quantify the levels of Hg wet deposition across the state, and to assess the contributions to Hg in precipitation from major local and regional emission sources. The measurement sites were located in Chicago, Peoria, Nilwood, and Carbondale, IL. We were not able to identify a clear spatial gradient in Hg wet deposition among the sites. At all four locations we frequently observed Hg concentrations in precipitation > 25 ng/L, while each site received > 10 μg/m2 of Hg wet deposition annually, suggesting a substantial impact from local and regional anthropogenic emission sources. We applied the multivariate statistical receptor model Positive Matrix Factorization (PMF to the measured Hg and trace element wet deposition amounts at the four sites. The results suggested that 60-83% of total Hg deposition at each site could be attributed to coal combustion emissions. Although we identified other source signatures in the precipitation composition, including cement manufacturing, metal smelting / waste incineration, and iron-steel production, these sources contributed substantially less to the measured amounts of Hg wet deposition. We also applied the hybrid receptor model Quantitative Transport Bias Analysis (QTBA to the Hg wet deposition data from each site to identify the major source regions associated with the measured values. Results suggested that sources in the Chicago/Gary, St. Louis, and Ohio River Valley urban/industrial areas had a substantial impact on Hg wet deposition, strongly supporting the conclusion that local and regional coal combustion was the largest source of Hg wet deposition in Illinois.

  8. Wet deposition of oxidized nitrogen in the United States Pacific Northwest for 2002

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This spatial data set was created by the U.S. Geological Survey (USGS) to represent the amount of wet deposition of oxidized nitrogen in the Pacific Northwest region...

  9. Global cloud and precipitation chemistry and wet deposition: tropospheric model simulations with ECHAM5/MESSy1

    OpenAIRE

    Tost, H; Jöckel, P.; Kerkweg, A.; Pozzer, A.; Sander, R.; Lelieveld, J.

    2007-01-01

    The representation of cloud and precipitation chemistry and subsequent wet deposition of trace constituents in global atmospheric chemistry models is associated with large uncertainties. To improve the simulated trace gas distributions we apply the new submodel SCAV, which includes detailed cloud and precipitation chemistry and present results of the atmospheric chemistry general circulation model ECHAM5/MESSy1. A good agreement with observed wet deposition fluxes for species causing acid rai...

  10. Elevated Trimethylarsine Oxide and Inorganic Arsenic in Northern Hemisphere Summer Monsoonal Wet Deposition.

    Science.gov (United States)

    Savage, Laurie; Carey, Manus; Hossain, Mahmud; Islam, M Rafiqul; de Silva, P Mangala C S; Williams, Paul N; Meharg, Andrew A

    2017-11-07

    For arsenic speciation, the inputs for wet deposition are not well understood. Here we demonstrate that trimethylarsine oxide (TMAO) and inorganic arsenic are the dominant species in monsoonal wet deposition in the summer Indian subcontinent, Bangladesh, with inorganic arsenic dominating, accounting for ∼80% of total arsenic in this medium. Lower concentrations of both species were found in monsoonal wet deposition in the winter Indian subcontinent, Sri Lanka. The only other species present was dimethylarsinic acid (DMAA), but this was usually below limits of detection (LoD). We hypothesize that TMAO and inorganic arsenic in monsoonal wet deposition are predominantly of marine origin. For TMAO, the potential source is the atmospheric oxidation of marine derived trimethylarsine. For inorganic arsenic, our evidence suggests entrainment of water column inorganic arsenic into atmospheric particulates. These conclusions are based on weather trajectory analysis and on the strong correlations with known wet deposition marine derived elements: boron, iodine, and selenium. The finding that TMAO and inorganic arsenic are widely present and elevated in monsoonal wet deposition identifies major knowledge gaps that need to be addressed regarding the understanding of arsenic's global cycle.

  11. Comparison of annual dry and wet deposition fluxes of selected pesticides in Strasbourg, France

    Energy Technology Data Exchange (ETDEWEB)

    Sauret, Nathalie [Marseilles University, Laboratoire Chimie Provence - UMR 6264, Campus Saint Charles, Case 29, 3 Place Victor Hugo, 13331 Marseilles Cedex 03 (France); Wortham, Henri [Marseilles University, Laboratoire Chimie Provence - UMR 6264, Campus Saint Charles, Case 29, 3 Place Victor Hugo, 13331 Marseilles Cedex 03 (France)], E-mail: Henri.Wortham@univ-provence.fr; Strekowski, Rafal [Marseilles University, Laboratoire Chimie Provence - UMR 6264, Campus Saint Charles, Case 29, 3 Place Victor Hugo, 13331 Marseilles Cedex 03 (France); Herckes, Pierre [Arizona State University, Department of Chemistry and Biochemistry, Tempe, AZ 85287-1604 (United States); Nieto, Laura Ines [Marseilles University, Laboratoire Chimie Provence - UMR 6264, Campus Saint Charles, Case 29, 3 Place Victor Hugo, 13331 Marseilles Cedex 03 (France)

    2009-01-15

    This work summarizes the results of a study of atmospheric wet and dry deposition fluxes of Deisopropyl-atrazine (DEA), Desethyl-atrazine (DET), Atrazine, Terbuthylazine, Alachlor, Metolachlor, Diflufenican, Fenoxaprop-p-ethyl, Iprodione, Isoproturon and Cymoxanil pesticides conducted in Strasbourg, France, from August 2000 through August 2001. The primary objective of this work was to calculate the total atmospheric pesticide deposition fluxes induced by atmospheric particles. To do this, a modified one-dimensional cloud water deposition model was used. All precipitation and deposition samples were collected at an urban forested park environment setting away from any direct point pesticide sources. The obtained deposition fluxes induced by atmospheric particles over a forested area showed that the dry deposition flux strongly contributes to the total deposition flux. The dry particle deposition fluxes are shown to contribute from 4% (DET) to 60% (cymoxanil) to the total deposition flux (wet + dry). - A modified one-dimensional cloud water deposition model is used to estimate the deposition fluxes of pesticides in the particle phase and compare the relative importance of dry and wet depositions.

  12. High mercury wet deposition at a “clean Air” site in Puerto Rico

    Science.gov (United States)

    Shanley, James B.; Engle, Mark A.; Scholl, Martha A.; Krabbenhoft, David P.; Brunette, Robert; Olson, Mark L.; Conroy, Mary E.

    2015-01-01

    Atmospheric mercury deposition measurements are rare in tropical latitudes. Here we report on seven years (April 2005 to April 2012, with gaps) of wet Hg deposition measurements at a tropical wet forest in the Luquillo Mountains, northeastern Puerto Rico, U.S. Despite receiving unpolluted air off the Atlantic Ocean from northeasterly trade winds, during two complete years the site averaged 27.9 μg m–2 yr–1 wet Hg deposition, or about 30% more than Florida and the Gulf Coast, the highest deposition areas within the U.S. These high Hg deposition rates are driven in part by high rainfall, which averaged 2855 mm yr–1. The volume-weighted mean Hg concentration was 9.8 ng L–1, and was highest during summer and lowest during the winter dry season. Rainout of Hg (decreasing concentration with increasing rainfall depth) was minimal. The high Hg deposition was not supported by gaseous oxidized mercury (GOM) at ground level, which remained near global background concentrations (<10 pg m–3). Rather, a strong positive correlation between Hg concentrations and the maximum height of rain detected within clouds (echo tops) suggests that droplets in high convective cloud tops scavenge GOM from above the mixing layer. The high wet Hg deposition at this “clean air” site suggests that other tropical areas may be hotspots for Hg deposition as well.

  13. ED-XRF analysis of wet deposition around metal recycling plant ...

    African Journals Online (AJOL)

    The study investigated the compositions of air emissions from a steel recycling factory with a view to assessing the impact of emissions from the factory on elemental deposition in the immediate environment of the factory. Wet atmospheric depositions samples were collected in four geographic directions and at varying ...

  14. 3D Numerical Modelling of Transport, Deposition and Resuspension of Highway Deposited Sediments in Wet Detention Ponds

    DEFF Research Database (Denmark)

    Bentzen, Thomas Ruby

    2009-01-01

    The paper presents results from an experimental and numerical study of flows and transport of primarily particle bound pollutants in highway wet detention ponds. The study presented here is part of a general investigation on road runoff and pollution in respect to wet detention ponds. The objective...... and particles in wet detention ponds is possible with application of a three dimensional RANS model and the advection/dispersion equation taken physical phenomena like wind, waves, deposition, erosion and consolidation of the bottom sediment into account....

  15. Atmospheric wet and dry deposition of trace elements at 10 sites in Northern China

    Science.gov (United States)

    Pan, Y. P.; Wang, Y. S.

    2015-01-01

    Atmospheric deposition is considered to be a major process that removes pollutants from the atmosphere and an important source of nutrients and contaminants for ecosystems. Trace elements (TEs), especially toxic metals deposited on plants and into soil or water, can cause substantial damage to the environment and human health due to their transfer and accumulation in food chains. Despite public concerns, quantitative knowledge of metal deposition from the atmosphere to ecosystems remains scarce. To advance our understanding of the spatiotemporal variations in the magnitudes, pathways, compositions and impacts of atmospherically deposited TEs, precipitation (rain and snow) and dry-deposited particles were collected simultaneously at 10 sites in Northern China from December 2007 to November 2010. The measurements showed that the wet and dry depositions of TEs in the target areas were orders of magnitude higher than previous observations within and outside China, generating great concern over the potential risks. The spatial distribution of the total (wet plus dry) deposition flux was consistent with that of the dry deposition, with a significant decrease from industrial and urban areas to suburban, agricultural and rural sites, while the wet deposition exhibited less spatial variation. In addition, the seasonal variation of wet deposition was also different from that of dry deposition, although they were both governed by the precipitation and emission patterns. For the majority of TEs that exist as coarse particles, dry deposition dominated the total flux at each site. This was not the case for potassium, nickel, arsenic, lead, zinc, cadmium, selenium, silver and thallium, for which the relative importance between wet and dry deposition fluxes varied by site. Whether wet deposition is the major atmospheric cleansing mechanism for the TEs depends on the size distribution of the particles. We found that atmospheric inputs of copper, lead, zinc, cadmium, arsenic and

  16. Atmospheric wet deposition of sulfur and nitrogen in Jiuzhaigou National Nature Reserve, Sichuan Province, China.

    Science.gov (United States)

    Qiao, Xue; Xiao, Weiyang; Jaffe, Daniel; Kota, Sri Harsha; Ying, Qi; Tang, Ya

    2015-04-01

    In the last two decades, remarkable ecological changes have been observed in Jiuzhaigou National Nature Reserve (JNNR). Some of these changes might be related to excessive deposition of sulfur (S) and nitrogen (N), but the relationship has not been quantified due to lack of monitoring data, particularly S and N deposition data. In this study, we investigated the concentrations, fluxes, and sources of S and N wet deposition in JNNR from April 2010 to May 2011. The results show that SO4(2-), NO3-, and NH4+ concentrations in the wet deposition were 39.4-170.5, 6.2-34.8, and 0.2-61.2 μeq L(-1), with annual Volume-Weighted Mean (VWM) concentrations of 70.5, 12.7, and 13.4 μeq L(-1), respectively. Annual wet deposition fluxes of SO4(2-), NO3-, and NH4+ were 8.06, 1.29, and 1.39 kg S(N)ha(-1), respectively, accounting for about 90% of annual atmospheric inputs of these species at the monitoring site. The results of Positive Matrix Factorization (PMF) analysis show that fossil fuel combustion, agriculture, and aged sea salt contributed to 99% and 83% of annual wet deposition fluxes of SO4(2-) and NO3-, respectively. Agriculture alone contributed to 89% of annual wet deposition flux of NH4+. Although wet deposition in JNNR was polluted by anthropogenic acids, the acidity was largely neutralized by the Ca2+ from crust and 81% of wet deposition samples had a pH higher than 6.00. However, acid rain mainly caused by SO4(2-) continued to occur in the wet season, when ambient alkaline dust concentration was lower. Since anthropogenic emissions have elevated S and N deposition and caused acid rain in JNNR, further studies are needed to better quantify the regional sources and ecological effects of S and N deposition for JNNR. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Assessing the emission sources of atmospheric mercury in wet deposition across Illinois.

    Science.gov (United States)

    Gratz, Lynne E; Keeler, Gerald J; Morishita, Masako; Barres, James A; Dvonch, J Timothy

    2013-03-15

    From August 4, 2007 to August 31, 2009, we collected event-based precipitation samples for mercury (Hg) and trace element analyses at four sites in Illinois (IL), USA. The objectives of these measurements were to quantify Hg wet deposition across the state, and to assess the contributions to Hg in precipitation from major local and regional emission sources. Monitoring sites were located, from north to south, in Chicago, Peoria, Nilwood, and Carbondale, IL. Measurements from these four sites demonstrated that a clear spatial gradient in Hg wet deposition was not evident across the state. Each site received>10μgm(-2) of Hg wet deposition annually, and these observed values were comparable to annual Hg wet deposition measurements from other event-based precipitation monitoring sites in source-impacted areas of the Midwestern U.S. We applied the multivariate statistical receptor model, Positive Matrix Factorization (EPA PMF v3.0), to the measured Hg and trace element wet deposition amounts at the four sites. Results suggested that 50% to 74% of total Hg wet deposition at each site could be attributed to coal combustion emissions. The other source signatures identified in the precipitation compositions included cement manufacturing, mixed metal smelting/waste incineration, iron-steel production, and a phosphorus source. We also applied a hybrid receptor model, Quantitative Transport Bias Analysis (QTBA), to the Hg wet deposition datasets to identify the major source regions associated with the measured values. The calculated QTBA probability fields suggested that transport from urban/industrial areas, such as Chicago/Gary, St. Louis, and the Ohio River Valley, resulted in some of the highest estimated event-based Hg wet deposition amounts at the four sites (potential mass transfer of up to 0.32μgm(-2)). The combined application of PMF and QTBA supported the hypothesis that local and regional coal combustion was the largest source of Hg wet deposition in Illinois

  18. Urbanization in China changes the composition and main sources of wet inorganic nitrogen deposition.

    Science.gov (United States)

    Huang, Juan; Zhang, Wei; Zhu, Xiaomin; Gilliam, Frank S; Chen, Hao; Lu, Xiankai; Mo, Jiangming

    2015-05-01

    Nowadays, nitrogen (N) deposition has become a growing global concern due to urbanization activities increasing the large amount of reactive N in the atmosphere. However, it remains unclear whether urbanization affects the composition and main sources of N deposition in rapidly urbanizing areas such as in China. One-year measurement of wet inorganic N deposition was conducted using ion-exchange resin (IER) columns in the range of 260 km from urban to rural areas in the Pearl River Delta (PRD) region, south China. An increasing pattern of wet inorganic deposition along the urbanization gradient was observed and it increased in the order: rural (15.26 ± 0.20 kg N ha(-1) year(-1)) urban (31.16 ± 0.44 kg N ha(-1) year(-1)) urban/suburban sites (34.15 ± 5.73 kg N ha(-1) year(-1)). Nitrate N (NO3 (-)-N) accounted for 53.5-79.1 % of total wet inorganic N deposition, indicating a significant negative correlation with distance from the urban core. Based on moss δ(15)N-values the main source of NO3 (-)-N was considered to be emitted from vehicles. Our results demonstrate that urbanization has large impacts on the regional pattern of wet inorganic N deposition. Thus, controlling NOx emission, especially vehicle emission will become an effective strategy for N pollution abatement in China.

  19. Five-year records of mercury wet deposition flux at GMOS sites in the Northern and Southern hemispheres

    Science.gov (United States)

    Sprovieri, Francesca; Pirrone, Nicola; Bencardino, Mariantonia; D'Amore, Francesco; Angot, Helene; Barbante, Carlo; Brunke, Ernst-Günther; Arcega-Cabrera, Flor; Cairns, Warren; Comero, Sara; Diéguez, María del Carmen; Dommergue, Aurélien; Ebinghaus, Ralf; Feng, Xin Bin; Fu, Xuewu; Garcia, Patricia Elizabeth; Gawlik, Bernd Manfred; Hageström, Ulla; Hansson, Katarina; Horvat, Milena; Kotnik, Jože; Labuschagne, Casper; Magand, Olivier; Martin, Lynwill; Mashyanov, Nikolay; Mkololo, Thumeka; Munthe, John; Obolkin, Vladimir; Ramirez Islas, Martha; Sena, Fabrizio; Somerset, Vernon; Spandow, Pia; Vardè, Massimiliano; Walters, Chavon; Wängberg, Ingvar; Weigelt, Andreas; Yang, Xu; Zhang, Hui

    2017-02-01

    The atmospheric deposition of mercury (Hg) occurs via several mechanisms, including dry and wet scavenging by precipitation events. In an effort to understand the atmospheric cycling and seasonal depositional characteristics of Hg, wet deposition samples were collected for approximately 5 years at 17 selected GMOS monitoring sites located in the Northern and Southern hemispheres in the framework of the Global Mercury Observation System (GMOS) project. Total mercury (THg) exhibited annual and seasonal patterns in Hg wet deposition samples. Interannual differences in total wet deposition are mostly linked with precipitation volume, with the greatest deposition flux occurring in the wettest years. This data set provides a new insight into baseline concentrations of THg concentrations in precipitation worldwide, particularly in regions such as the Southern Hemisphere and tropical areas where wet deposition as well as atmospheric Hg species were not investigated before, opening the way for future and additional simultaneous measurements across the GMOS network as well as new findings in future modeling studies.

  20. Assessing pesticide wet deposition risk within a small agricultural watershed in the Southeastern Coastal Plain (USA).

    Science.gov (United States)

    Potter, Thomas L; Coffin, Alisa W

    2017-02-15

    Pesticide volatilization and deposition with precipitation is widely documented and has been connected to adverse ecological impact. Here we describe a 3-yr study of current use and legacy pesticides in event-based rain samples within a 123-ha agricultural watershed. Crops in farm fields were documented quarterly with data used to estimate target compound use. The median number of pesticide detections in samples was 6. The fungicide, chlorothalonil which was used most intensively was detected in nearly all samples. It had the highest mean and peak concentrations with total deposition ≈0.1% of the estimated amount applied. The insecticide endosulfan also had relatively high use with behavior mirroring chlorothalonil. There was strong seasonal variation in concentration and depositional dynamics with the highest values measured during growing seasons. Similar behavior was observed with other compounds detected in rain samples with a general decrease in deposition and mean concentrations as use decreased. Comparison of measured concentrations to values associated with toxic impact on aquatic organisms indicated that chlorothalonil, endosulfan, chlorpyrifos, malathion and atrazine may contribute to adverse impact. The number of samples exceeding risk endpoints ranged from 1 to 77%. The highest value was for endosulfan; however its on-going phase-out is expected to reduce risks. Another finding was that the wet deposition of the herbicide, metolachlor exceeded measured runoff rates in the watershed by 5-fold. The study has demonstrated that localized pesticide wet deposition may present ecological risks and that volatilization and wet deposition is an important pesticide transport pathway at the local scale. Findings point to the need to include wet deposition in assessments of pesticide ecological risk and environmental fate. Published by Elsevier B.V.

  1. Influence of summer and winter climate variability on nitrogen wet deposition in Norway

    Directory of Open Access Journals (Sweden)

    L. R. Hole

    2008-03-01

    Full Text Available Dominating wind patterns around Norway may change due to climate warming. This could affect transport of polluted air masses and precipitation. Here, we study relations between reactive nitrogen wet deposition and air mass transport during summer and winter expressed in the form of climate indices, at seven sites in Southern Norway for the period 1980–2005. Atmospheric nitrate concentrations decreased with 0 to 50% in the period, particularly at sites with little precipitation, and mostly during 1990–2005. For comparison, reported reductions in emissions of oxidised nitrogen in Europe in 1989–2003 were 23%. Climate indices explained up to 36% of the variation in winter nitrate deposition at the western and northern sites – and also explained 60% of the variation in winter precipitation (R=0.77. This suggests that the variation in nitrate wet deposition is closely related to variation in precipitation, and that the climate indices seem to also partly control the variation in atmospheric nitrate concentrations (R=−0.45 at coastal sites. At the coastal sites, local air temperature was highly correlated (R=0.84 with winter nitrate deposition, suggesting that warm, humid winter weather results in increased wet nitrate deposition. For ammonia the pattern was similar, but this compound is more influenced by local sources. Expected severe increase in precipitation in western and northern regions as a consequence of climate change suggest that nitrogen deposition in these areas will increase under global warming if emissions are held constant.

  2. A multi-resolution assessment of the Community Multiscale Air Quality (CMAQ model v4.7 wet deposition estimates for 2002–2006

    Directory of Open Access Journals (Sweden)

    K. W. Appel

    2011-05-01

    Full Text Available This paper examines the operational performance of the Community Multiscale Air Quality (CMAQ model simulations for 2002–2006 using both 36-km and 12-km horizontal grid spacing, with a primary focus on the performance of the CMAQ model in predicting wet deposition of sulfate (SO4=, ammonium (NH4+ and nitrate (NO3. Performance of the wet deposition estimates from the model is determined by comparing CMAQ predicted concentrations to concentrations measured by the National Acid Deposition Program (NADP, specifically the National Trends Network (NTN. For SO4= wet deposition, the CMAQ model estimates were generally comparable between the 36-km and 12-km simulations for the eastern US, with the 12-km simulation giving slightly higher estimates of SO4= wet deposition than the 36-km simulation on average. The result is a slightly larger normalized mean bias (NMB for the 12-km simulation; however both simulations had annual biases that were less than ±15 % for each of the five years. The model estimated SO4= wet deposition values improved when they were adjusted to account for biases in the model estimated precipitation. The CMAQ model underestimates NH4+ wet deposition over the eastern US, with a slightly larger underestimation in the 36-km simulation. The largest underestimations occur in the winter and spring periods, while the summer and fall have slightly smaller underestimations of NH4+ wet deposition. The underestimation in NH4+ wet deposition is likely due in part to the poor temporal and spatial representation of ammonia (NH3 emissions, particularly those emissions associated with fertilizer applications and NH3 bi-directional exchange. The model performance for estimates of NO3 wet deposition are

  3. Assessing the Sources of Atmospheric Mercury Wet Deposited in Florida, USA

    Directory of Open Access Journals (Sweden)

    Dvonch J. T.

    2013-04-01

    Full Text Available From October 2008 through August 2010, event-based precipitation samples for mercury (Hg, trace elements, and major ions analysis were collected at six monitoring sites in Florida, USA. The objectives of these measurements were to quantify the levels of Hg wet deposition across the state, and to assess the contributions to Hg in precipitation from major local and regional emission sources in support of a Hg Total Maximum Daily Load (TMDL project. The measurement sites were located in Pensacola, Jacksonville, Orlando, Tampa, Davie, and Everglades National Park. For the period April 2009 through August 2010, Hg wet deposition rates ranged from 26.8 to 38.7 μg/m2 across the six sites. We observed a strong seasonal pattern, with increases in measured Hg concentrations and Hg wet deposition occurring during the summer months, which was further pronounced at the southern sites. We also observed a clear overall spatial gradient in Hg wet deposition, increasing across sites from north to south.

  4. Spatiotemporal variability of wet atmospheric nitrogen deposition to the Neuse River Estuary, North Carolina

    Energy Technology Data Exchange (ETDEWEB)

    Whitall, D.R.; Paerl, H.W. [University of North Carolina, Morehad City, NC (USA). Inst. of Marine Sciences

    2001-10-01

    Excessive nitrogen (N) loading to N-sensitive waters such as the Neuse River estuary (North Carolina) has been shown to promote changes in microbial and algal community composition and function (harmful algal blooms), hypoxia and anoxia, and fish kills. Previous studies have estimated that wet atmospheric deposition of nitrogen (WAD-N), as deposition of dissolved inorganic nitrogen (DIN: NO{sub 3}{sup -} NH{sub 3}/NH{sub 4}{sup +}) and dissolved organic nitrogen, may contribute at least 15% of the total externally supplied or 'new' N flux to the coastal waters of North Carolina. In a 3-yr study from June 1996 to June 1999, the weekly wet deposition of inorganic and organic N was counted at eleven sites on a northwest-southeast transect in the watershed. The annual mean total (wet DIN + wet organics) WAD-N flux for (15,026 Mg N/yr). Seasonally the spring (March-May) and summer (June - August) months contain the highest total weekly N depositions; this pattern appears to be driven by N concentration in precipitation. There is also spatial variability in WAD-N deposition; in general, the upper portion of the watershed receives the lowest annual deposition and the middle portion of the watershed receives the highest deposition. Based on a range of watershed N retention and in-stream riverine processing values, it was estimated that this flux contributes approximately 24% of the total 'new' N flux to the estuary. 61 refs., 4 figs., 4 tabs.

  5. Four Types of Deposits From Wet Conditions on Early Mars

    Science.gov (United States)

    2008-01-01

    Each of these four panels shows a close-up view of a different type of geological deposit formed with the involvement of water, based on observations by NASA's Mars Reconnaissance Orbiter. All four date from the earliest period of Martian history, called the Noachian Period. The upper-left panel shows carbonates overlying clays in the Nili Fossae region of Mars. The view combines color-coded information from infrared spectral observations by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) with an underlying black-and-white image from the High Resolution Imaging Science Experiment (HiRISE) camera. Beneath a rough-textured capping rock unit (purple) lie banded olivine-bearing layers (yellow), which in some places have been partially or wholly altered to carbonate (green). The upper-right panel shows phyllosilicates and chlorides in the Terra Sirenum region, observed by CRISM and HiRISE. Medium-toned, finely fractured rocks containing chloride salts either underlie higher-standing, light-toned phyllosilicates or fill in low spots between them. Both sit on dark, eroded volcanic material. The lower-left panel shows the upper portion of canyon wall in Coprates Chasma, observed by HiRISE and CRISM. The chasm rim cuts across the middle of the image. The wall slopes down to the top of the image and continues outside the region shown, exposing multiple phyllosilicate-bearing layers in a section of rock 7 kilometers (4 miles) thick. Two of the layers shown here are finely fractured aluminum clays that dominate the lower half of the image, underlain by thin beds of iron-magnesium clays at the top of the image. The dark material is a remnant of an overlying layer of basaltic sand that has been partly eroded away by the wind. The lower-right panel shows phyllosilicates with vertically layered compositions in Mawrth Vallis, observed by HiRISE (presented in enhanced color) and CRISM. The brown-colored knob in the middle of the scene is a remnant of cap rock that

  6. Wet deposition and sources of inorganic nitrogen in the Three Gorges Reservoir Region, China.

    Science.gov (United States)

    Wang, Huanbo; Shi, Guangming; Tian, Mi; Chen, Yang; Qiao, Baoqing; Zhang, Liuyi; Yang, Fumo; Zhang, Leiming; Luo, Qiong

    2017-11-02

    Precipitation samples were collected at five rural and one urban sites in the Three Gorges Reservoir Region (TGR), China from March 2014 to February 2016. The inorganic reactive nitrogen (Nr) contents were analysed to investigate their wet deposition flux, budget, and sources in the area. Annual Nr wet deposition varied from 7.1 to 23.4 kg N ha(-1) yr(-1) over the six sites during the two-year study campaign. The six-site average Nr wet deposition flux was 17.1 and 11.7 kg N ha(-1) yr(-1) in 2014 and 2015, respectively, with 71% from NH4(+) and 29% from NO3(-). Dry deposition flux was estimated using the inferential method, which combined the measured ambient concentrations and modelled dry deposition velocities. The total (dry + wet) Nr deposition fluxes were estimated to be 21.4 kg N ha(-1) yr(-1) in 2014 and 16.0 kg N ha(-1) yr(-1) in 2015 at rural sites, and 31.4 and 25.3 kg N ha(-1) yr(-1) at the urban site. Annual average volume weighted mean (VWM) concentrations in precipitation at all the six sites differed little for NO3(-) but up to a factor of 2.0 for NH4(+) with the highest value at the urban site. Industrial emissions, agricultural emissions, soil dust, and biomass burning were identified as potential sources of the major inorganic ions in precipitation using factor analysis and correlation analysis. Conditional probability function (CPF) analysis indicated that the urban site was predominantly affected by industrial emissions from a power plant, cement manufactory, and salt chemical facility located ∼13 km southeast of the sampling site. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  7. Effects of convective parameterization schemes on estimation of the annual wet deposition over Northeast Asia

    Science.gov (United States)

    Kim, Hong-Rae; Kim, Yun-Jong; Kim, Cheol-Hee

    2011-01-01

    This paper presents technique used to estimate annual total wet depositions of NO 3- and SO 42-, and describes their sensitivities arising from various convective parameterization schemes over Northeast Asia. The representative synoptic meteorological conditions for the precipitation were identified by employing a cluster analysis technique, and four cumulus convective parameterization schemes, the Anthes-Kuo (AK), Betts-Miller (BM), Grell (GR), and Kain-Fritsch 2 (KF2) schemes, were applied to estimate annual wet deposition simulations. The four convective parameterization schemes were found to reproduce the overall observed precipitation band for each of the classified synoptic patterns. When cluster analysis was used with these four schemes, the estimated annual total wet depositions of SO 42- and NO 3- over South Korea were found to reach 184-197 and 277-337 kton year -1, respectively, with the highest estimation found with the KF2 scheme. These estimates were higher than the results of the continuous full year-long simulations by three dimensional comprehensive acid deposition model, which found values of 130 kton year -1 for SO 42- and 270 kton year -1 for NO 3-. There was a 15.2% variability in the annual total precipitation from the use of the different convective parameterizations of the four schemes, but the annual total wet depositions of the four cloud parameterization schemes were in good agreement, with estimated variabilities of approximately 9.1 and 8.8% for SO 42- and NO 3-, respectively. At less than ˜10%, these variations were small and negligible in an estimation of the long-term depositions over the region of Korean Peninsula.

  8. Simplified data assimilation for simulating wet deposition distribution of radioactive materials in FDNPP accident

    Science.gov (United States)

    Saya, A.; Yoshikane, T.; Chang, E. C.; Yoshimura, K.

    2015-12-01

    Due to the massive earthquakes and tsunami on March 11th 2011 in Eastern Japan, Fukushima Daiichi Nuclear Power Plant (FDNPP) was severely damaged. Radioactive materials were released and spread out by atmospheric advection-diffusion. Especially on March 21 - 23th when precipitation was observed, "hotspot" where the high concentration was detected locally. This area was formed in the metropolitan area in Kanto region. Thus, pollution at water treatment plants because of the deposition became a concern. Therefore, the reliable information of the hotspot is expected. Currently, atmospheric transport simulations by numerical models are developed for reproduction of the distribution. However, there are some uncertainties in the simulations. In the case of hotspot, accuracy of simulated precipitation have to be well considered because the hotspot seemed to be formed by wet deposition. We modified the stable isotope mode of Regional Spectral Model (IsoRSM) to enable to simulate the transport of the radioactive tracers, namely 131I and 137Cs, by including the dry and wet deposition processes. As the simplified data assimilation, simulated precipitation was replaced with Radar-AMeDAS precipitation data (RAP). RAP was assimilated in the post-process, after running simulations, to redistribute wet deposition of 137Cs. The ratio of 137Cs deposited from the cumulative vertical column with precipitation in the domain was not changed, however its pattern was redistributed corresponding with RAP and simulated concentration. As a result, the redistributed wet deposition was within factor 10 to 2 compared with the fallout data in Kanto region, and further data assimilation would be contributed. In addition, we found that due to the arrival time of the plume in the morning on 21st and the border time of daily observation data of fallout, validation result might be worse even though hourly distributions are well simulated.

  9. Sulfate-rich eolian and wet interdune deposits, erebus crater, meridiani Planum, Mars

    Science.gov (United States)

    Metz, J.M.; Grotzinger, J.P.; Rubin, D.M.; Lewis, K.W.; Squyres, S. W.; Bell, J.F.

    2009-01-01

    This study investigates three bedrock exposures at Erebus crater, an ?? 300 m diameter crater approximately 4 km south of Endurance crater on Mars. These outcrops, called Olympia, Payson, and Yavapai, provide additional evidence in support of the dune-interdune model proposed for the formation of the deposits at the Opportunity landing site in Meridiani Planum. There is evidence for greater involvement of liquid water in the Olympia outcrop exposures than was observed in Eagle or Endurance craters. The Olympia outcrop likely formed in a wet interdune and sand sheet environment. The facies observed within the Payson outcrop, which is likely stratigraphically above the Olympia outcrop, indicate that it was deposited in a damp-wet interdune, sand sheet, and eolian dune environment. The Yavapai outcrop, which likely stratigraphically overlies the Payson outcrop, indicates that it was deposited in primarily a sand sheet environment and also potentially in an eolian dune environment. These three outcrop exposures may indicate an overall drying-upward trend spanning the stratigraphic section from its base at the Olympia outcrop to its top at the Yavapai outcrop. This contrasts with the wetting-upward trend seen in Endurance and Eagle craters. Thus, the series of outcrops seen at Meridiani by Opportunity may constitute a full climatic cycle, evolving from dry to wet to dry conditions. ?? 2009, SEPM (Society for Sedimentary Geology).

  10. Long term precipitation chemistry and wet deposition in a remote dry savanna site in Africa (Niger

    Directory of Open Access Journals (Sweden)

    C. Galy-Lacaux

    2009-03-01

    , the total mean wet deposition flux in the Sahelian region is of 60.1 mmol.m−2.yr−1 ±25%. Finally, Banizoumbou measurements are compared to other long-term measurements of precipitation chemistry in the wet savanna of Lamto (Côte d'Ivoire and in the forested zone of Zoétélé (Cameroon. The total chemical loading presents a maximum in the dry savanna and a minimum in the forest (from 143.7, 100.2 to 86.6 μeq.l−1, associated with the gradient of terrigeneous sources. The wet deposition fluxes present an opposite trend, with 60.0 mmol.m−2.yr−1 in Banizoumbou, 108.6 mmol.m−2.yr−1 in Lamto and 162.9 mmol.m−2.yr−1 in Zoétélé, controlled by rainfall gradient along the ecosystems transect.

  11. Wet and Dry Atmospheric Depositions of Inorganic Nitrogen during Plant Growing Season in the Coastal Zone of Yellow River Delta

    Directory of Open Access Journals (Sweden)

    Junbao Yu

    2014-01-01

    Full Text Available The ecological problems caused by dry and wet deposition of atmospheric nitrogen have been widespread concern in the world. In this study, wet and dry atmospheric depositions were monitored in plant growing season in the coastal zone of the Yellow River Delta (YRD using automatic sampling equipment. The results showed that SO42- and Na+ were the predominant anion and cation, respectively, in both wet and dry atmospheric depositions. The total atmospheric nitrogen deposition was ~2264.24 mg m−2, in which dry atmospheric nitrogen deposition was about 32.02%. The highest values of dry and wet atmospheric nitrogen deposition appeared in May and August, respectively. In the studied area, NO3-–N was the main nitrogen form in dry deposition, while the predominant nitrogen in wet atmospheric deposition was NH4+–N with ~56.51% of total wet atmospheric nitrogen deposition. The average monthly attribution rate of atmospheric deposition of NO3-–N and NH4+–N was ~31.38% and ~20.50% for the contents of NO3-–N and NH4+–N in 0–10 cm soil layer, respectively, suggested that the atmospheric nitrogen was one of main sources for soil nitrogen in coastal zone of the YRD.

  12. Impact of atmospheric wet deposition on phytoplankton community structure in the South China Sea

    Science.gov (United States)

    Cui, Dong-Yang; Wang, Jiang-Tao; Tan, Li-Ju; Dong, Ze-Yi

    2016-05-01

    The South China Sea (SCS), which is the largest marginal sea in East Asia, plays a significant role in regional climate change. However, research on the phytoplankton community structure (PCS) response to atmospheric wet deposition remains inadequate. In this study, field incubation experiments were performed to survey the impact of atmospheric wet deposition on the PCS in the SCS in December 2013. Results indicate that the mean dissolved inorganic nitrogen/dissolved inorganic phosphorous (DIN/DIP) ratio in rainwater was 136, which was higher than that in seawater. Under low initial nutrient concentrations, rainwater inputs not only significantly increased total chlorophyll a (Chl a) concentrations but also potentially altered the PCS. The total Chl a concentration increased 1.7-, 1.9-, and 1.6-fold; microphytoplankton increased 2.6-, 3.2-, and 1.7-fold with respect to their initial values in the 5%, 10% addition, and 10% addition (filtered) treatment samples, respectively. Finally, microphytoplankton contributed 61% to the total Chl a concentration in 10% addition treatment samples. Differences in the nutrients induced by atmospheric wet deposition resulted in a shift in the advantage from picophytoplankton to microphytoplankton. Diatoms became the predominant species, accounting for 55% of the total abundance after rainwater addition.

  13. Estimation and mapping of wet and dry mercury deposition across northeastern North America

    Science.gov (United States)

    Miller, E.K.; Vanarsdale, A.; Keeler, G.J.; Chalmers, A.; Poissant, L.; Kamman, N.C.; Brulotte, R.

    2005-01-01

    Whereas many ecosystem characteristics and processes influence mercury accumulation in higher trophic-level organisms, the mercury flux from the atmosphere to a lake and its watershed is a likely factor in potential risk to biota. Atmospheric deposition clearly affects mercury accumulation in soils and lake sediments. Thus, knowledge of spatial patterns in atmospheric deposition may provide information for assessing the relative risk for ecosystems to exhibit excessive biotic mercury contamination. Atmospheric mercury concentrations in aerosol, vapor, and liquid phases from four observation networks were used to estimate regional surface concentration fields. Statistical models were developed to relate sparsely measured mercury vapor and aerosol concentrations to the more commonly measured mercury concentration in precipitation. High spatial resolution deposition velocities for different phases (precipitation, cloud droplets, aerosols, and reactive gaseous mercury (RGM)) were computed using inferential models. An empirical model was developed to estimate gaseous elemental mercury (GEM) deposition. Spatial patterns of estimated total mercury deposition were complex. Generally, deposition was higher in the southwest and lower in the northeast. Elevation, land cover, and proximity to urban areas modified the general pattern. The estimated net GEM and RGM fluxes were each greater than or equal to wet deposition in many areas. Mercury assimilation by plant foliage may provide a substantial input of methyl-mercury (MeHg) to ecosystems. ?? 2005 Springer Science+Business Media, Inc.

  14. Controlling Factors of Long-Term Trends in Mercury Wet Deposition and Precipitation Concentrations at Huntington Wildlife Forest

    Science.gov (United States)

    Ye, Z.; Mao, H.; Driscoll, C. T.

    2015-12-01

    Observations from the Mercury Deposition Network (MDN) at Huntington Wildlife Forest (HWF) suggested that a significant decline (r2 = 0.34, p = 0.03) from 2000 to 2013 in volume weighted mean (VWM) Hg concentrations in precipitation was linked to Hg emission decreases in the United States, especially in the Northeast and Midwest, and yet Hg wet deposition has remained fairly constant over the past two decades. The present study aimed to investigate the climatic, terrestrial, and anthropogenic factors that influenced the decadal pattern in Hg wet deposition in upstate NY. In spring and summer, when Hg wet deposition was the strongest, significant positive correlation (r2 = 0.89, p < 0.0001 in spring; r2 = 0.58, p = 0.002 in summer) of Hg wet deposition with precipitation was found. Increases in precipitation during these seasons could offset the decreasing of Hg concentration in precipitation. Besides, springtime positive correlation (r2 = 0.35, p = 0.02) between precipitation and the North Atlantic Oscillation (NAO) index together with geopotential height and wind speed analysis indicated that large-scale dynamical forcing was likely an important factor influencing the long term trend in springtime Hg wet deposition at HWF. To further quantify the roles of meteorological and anthropogenic factors in Hg wet deposition, the Community Multiscale Air Quality (CMAQ) model was employed using an algorithm depicting state-of-the-art Hg chemistry mechanism and up-to-date Hg emission inventories evaluated with MDN and Atmospheric Mercury Network (AMNet) measurement data. CMAQ simulations with a constant vs. realistic meteorological conditions for multiple warm seasons (including spring and summer) were used to characterize and quantify the impacts of inter-annual variability of precipitation and atmospheric circulation on Hg wet deposition. In addition, contributions to Hg wet deposition from decreases in anthropogenic emissions in NYS and nation-wide were quantified from

  15. Sensitivity study of the wet deposition schemes in the modelling of the Fukushima accident.

    Science.gov (United States)

    Quérel, Arnaud; Quélo, Denis; Roustan, Yelva; Mathieu, Anne; Kajino, Mizuo; Sekiyama, Thomas; Adachi, Kouji; Didier, Damien; Igarashi, Yasuhito

    2016-04-01

    The Fukushima-Daiichi release of radioactivity is a relevant event to study the atmospheric dispersion modelling of radionuclides. Actually, the atmospheric deposition onto the ground may be studied through the map of measured Cs-137 established consecutively to the accident. The limits of detection were low enough to make the measurements possible as far as 250km from the nuclear power plant. This large scale deposition has been modelled with the Eulerian model ldX. However, several weeks of emissions in multiple weather conditions make it a real challenge. Besides, these measurements are accumulated deposition of Cs-137 over the whole period and do not inform of deposition mechanisms involved: in-cloud, below-cloud, dry deposition. A comprehensive sensitivity analysis is performed in order to understand wet deposition mechanisms. It has been shown in a previous study (Quérel et al, 2016) that the choice of the wet deposition scheme has a strong impact on the assessment of the deposition patterns. Nevertheless, a "best" scheme could not be highlighted as it depends on the selected criteria: the ranking differs according to the statistical indicators considered (correlation, figure of merit in space and factor 2). A possibility to explain the difficulty to discriminate between several schemes was the uncertainties in the modelling, resulting from the meteorological data for instance. Since the move of the plume is not properly modelled, the deposition processes are applied with an inaccurate activity in the air. In the framework of the SAKURA project, an MRI-IRSN collaboration, new meteorological fields at higher resolution (Sekiyama et al., 2013) were provided and allows to reconsider the previous study. An updated study including these new meteorology data is presented. In addition, a focus on several releases causing deposition in located areas during known period was done. This helps to better understand the mechanisms of deposition involved following the

  16. Standard test method for determining atmospheric chloride deposition rate by wet candle method

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2002-01-01

    1.1 This test method covers a wet candle device and its use in measuring atmospheric chloride deposition (amount of chloride salts deposited from the atmosphere on a given area per unit time). 1.2 Data on atmospheric chloride deposition can be useful in classifying the corrosivity of a specific area, such as an atmospheric test site. Caution must be exercised, however, to take into consideration the season because airborne chlorides vary widely between seasons. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  17. Investigation of mercury wet deposition physicochemistry in the Ohio River Valley through automated sequential sampling.

    Science.gov (United States)

    White, Emily M; Landis, Matthew S; Keeler, Gerald J; Barres, James A

    2013-03-15

    Intra-storm variability and soluble fractionation was explored for summer-time rain events in Steubenville, Ohio to evaluate the physical processes controlling mercury (Hg) in wet deposition in this industrialized region. Comprehensive precipitation sample collection was conducted from July through September 2006 using three different methods to evaluate both soluble and insoluble fractions as well as scavenging and washout properties of Hg and a suite of trace elements. Real-time filtration of event total precipitation revealed that 61±17% (mean±standard deviation) of Hg in wet deposition was in a soluble form. Comparison of total and dissolved element concentrations (solubility fractionation) showed the following order of decreasing solubility: S>Na>Se>Ca>Mg>Hg>As>Mn>V>Cr>Fe>La≈Ce ranging from 95% (S) to 4% (Ce). To examine removal mechanisms occurring during the course of a precipitation event, discrete, sequential sub-event precipitation samples were collected. Results indicated that Hg had lower "scavenging coefficients" (the rate of Hg concentration decrease throughout the events) than the majority of elements analyzed, indicating that either (i) Hg is incorporated into rain via gas phase inclusion or particulate nucleation within cloud, or (ii) Hg is available in the boundary layer for scavenging, even in the latter stages of precipitation. The Hg scavenging coefficient (-0.39) was low compared to S (-0.73), a co-pollutant of Hg. When compared to an upwind, regionally representative site, the scavenging coefficient of Hg for the locally influenced precipitation was 25% lower. This observation suggests that a continuous feed of soluble Hg was the reason for the low scavenging coefficient. Overall, this investigation of Hg wet deposition in Steubenville indicates that the physical and chemical properties of Hg emissions are driving the elevated deposition rates observed near point sources. Published by Elsevier B.V.

  18. Wet nitrogen and phosphorus deposition in the eutrophication of the Lagos Lagoon, Nigeria.

    Science.gov (United States)

    Oladosu, Najeem O; Abayomi, Akeem A; Olayinka, Kehinde O; Alo, Babajide I

    2017-03-01

    Air pollution is influenced by wind-aided particulate suspension, open-air waste burning, and fossil fuel combustion. The pollutants from these sources eventually deposit on ambient surfaces. Atmospheric wet deposition into Lagos Lagoon may be significant additions to the nutrient levels of the eutrophic lagoon. Precipitation was monitored at three stations in the Lagos Lagoon basin from May to November, 2012, in order to estimate the contribution of wet deposition to the nutrient cycles of the lagoon. Water samples were digested with potassium persulfate, and the species of phosphorus (P) and nitrogen (N) were analyzed by colorimetric methods. The mean [NO 3 - +NO 2 - ]-N level was 0.39 ± 0.51 kg ha -1  month -1 . The average total N was 3.16 ± 6.39 kg ha -1  month -1 . The mean soluble reactive P was lower than the [NO 3 - +NO 2 - ]-N averaging 0.06 ± 0.09 (at control site S2) to 0.24 ± 0.10 kg ha -1  month -1 (at site S1). Average total P was 1.25 ± 0.82 kg ha -1  month -1 . The annual total N (May-September) was 4.55 (at S2) to 32.4 kg ha -1  year -1 (at S3). The annual total P (May-November) over Lagos Lagoon basin was 5.06 kg ha -1  year -1 (at S2). This study demonstrated that wet deposition of anthropogenically derived nutrients to the Lagos Lagoon is ongoing and may represent a considerable proportion of the total nutrient loading to it. The increased P availability in the wet deposition is likely responsible for the water hyacinths, which usually blossom on Lagos Lagoon during the late rainy season, and the reported harmattan-season bottom water hypoxia.

  19. Soil wetting processes at high temporal resolution in a semiarid mediterranean watershed with scattered tree cover

    Science.gov (United States)

    Lozano-Parra, Javier; van Schaik, Loes; Schnabel, Susanne; Gómez-Gutiérrez, Álvaro

    2015-04-01

    Soil wetting processes play a key role for the distribution of water and solutes and thereby for the water availability for plants. However, characterization of such processes (from slower to faster flows), frequency of occurrence, and factors that cause them, are still poorly known. This characterization is important in hydrological studies because enables a better understanding of spatio-temporal variability of water resources and allows improving the design of models. Using a method based on the maximal soil water increase registered by a sensor over a minimum given time interval during a rainfall event, types of soil wetting processes were classified and quantified. For this, capacitance sensors which registered the volumetric water content at high temporal resolution (30-min) along of more than two hydrological years (mainly for 2010-2011 and 2011-2012), were installed in soil profiles at 5, 15 cm, and 5 cm above the bedrock and depending on soil depth. This distribution along the soil profile is justified because soils are generally very shallow and most of the roots are concentrated in the upper layer. The sensors were gathered in 9 soil moisture stations characterized by lithology, topographic position, as well as by different vegetation covers: under tree canopy, under shrub, and in open spaces or grasslands. Besides, the data mining technique Multivariate Adaptive Regression Spline (MARS) was used to identify and rank the factors influencing flow types as well as modelling their occurrence. The work was carried out in an experimental catchment of the Spanish region of Extremadura. Results indicated that there is a general behavior or pattern of soil moisture dynamics in the catchment with a dominant occurrence of slower soil wetting processes (>50%), which may be considered as matrix flows, and a low occurrence of those faster processes (process, so that the ecological role of both flow types becomes prominent in water-limited environments. Statistical

  20. Wet atmospheric deposition of organic carbon: An underreported source of carbon to watersheds in the northeastern United States

    Science.gov (United States)

    Iavorivska, Lidiia; Boyer, Elizabeth W.; Grimm, Jeffrey W.

    2017-03-01

    We measured wet atmospheric deposition of dissolved organic carbon (DOC) over 6 years at a network of 12 monitoring sites across Pennsylvania, quantified rates of wet DOC deposition, and developed the first statewide estimates of inputs of DOC to watersheds via wet deposition. Average annual volume-weighted concentration of DOC was 0.71 mg C L-1. Annual wet deposition fluxes of DOC varied between sites and years, ranging from 3 to 13 kg C ha-1 yr-1, with an average value of 8 kg C ha-1 yr-1 across all sites and years and are of the same order of magnitude as literature values for riverine organic carbon fluxes in the northeastern United States. The rates of wet DOC deposition showed a pronounced seasonality and spatial distribution, with highest deposition rates observed in the summer, especially at the sites located in western Pennsylvania. Significant links between DOC and inorganic constituents in precipitation, such as sulfate and inorganic nitrogen forms, point to the similarity of sources and atmospheric processing and suggest that DOC may potentially affect their atmospheric transport and ecological fate. Observational data resulting from this study underscore the potential significance of atmospheric deposition as an external input of reactive carbon species to watersheds and may be useful for constraining atmospheric carbon models and evaluating atmospheric influences on ecosystems.

  1. Wet and dry atmospheric deposition on TiO{sub 2} coated glass

    Energy Technology Data Exchange (ETDEWEB)

    Chabas, Anne, E-mail: anne.chabas@lisa.univ-paris12.f [Laboratoire Interuniversitaire des Systemes Atmospheriques, Universite Paris 12, Universite Paris 7, CNRS, 61 avenue du General de Gaulle, 94010 Creteil (France); Gentaz, Lucile; Lombardo, Tiziana; Sinegre, Romain [Laboratoire Interuniversitaire des Systemes Atmospheriques, Universite Paris 12, Universite Paris 7, CNRS, 61 avenue du General de Gaulle, 94010 Creteil (France); Falcone, Roberto [Stazione Sperimentale del Vetro, Calle Briati 10, 30141 Murano, Venezia (Italy); Verita, Marco [Laboratorio di Analisi dei Materiali Antichi LAMA, Universita IUAV di Venezia, S. Polo 2648, 30125 Venezia (Italy); Cachier, Helene [Laboratoire des Sciences du Climat et de l' Environnement, CNRS-CEA, Orme des Merisiers, bat 701, 91191Gif sur Yvette (France)

    2010-12-15

    To prevent the soiling of glass window used in the built environment, the use TiO{sub 2} coated products appears an important application matter. To test the cleaning efficiency and the sustainability of self-cleaning glass, a field experiment was conducted under real life condition, on a site representative of the background urban pollution. Samples of float glass, used as reference, and commercialized TiO{sub 2} coated glasses were exposed to dry and wet atmospheric deposition during two years. The crossed optical, chemical and microscopic evaluations performed, after withdrawal, allowed highlighting a sensible difference between the reference and the self-cleaning substrate in terms of accumulation, nature, abundance and geometry of the deposit. This experiment conducted in real site emphasized on the efficacy of self-cleaning glass to reduce the maintenance cost. - This paper evaluates the self-cleaning glass efficiency highlighting its ability to prevent soiling and to be used as a mean of remediation.

  2. Modeling dry and wet deposition of sulfate, nitrate, and ammonium ions in Jiuzhaigou National Nature Reserve, China using a source-oriented CMAQ model: Part I. Base case model results.

    Science.gov (United States)

    Qiao, Xue; Tang, Ya; Hu, Jianlin; Zhang, Shuai; Li, Jingyi; Kota, Sri Harsha; Wu, Li; Gao, Huilin; Zhang, Hongliang; Ying, Qi

    2015-11-01

    A source-oriented Community Multiscale Air Quality (CMAQ) model driven by the meteorological fields generated by the Weather Research and Forecasting (WRF) model was used to study the dry and wet deposition of nitrate (NO3(-)), sulfate (SO4(2-)), and ammonium (NH4(+)) ions in the Jiuzhaigou National Nature Reserve (JNNR), China from June to August 2010 and to identify the contributions of different emission sectors and source regions that were responsible for the deposition fluxes. The model performance is evaluated in this paper and the source contribution analyses are presented in a companion paper. The results show that WRF is capable of reproducing the observed precipitation rates with a Mean Normalized Gross Error (MNGE) of 8.1%. Predicted wet deposition fluxes of SO4(2-) and NO3(-) at the Long Lake (LL) site (3100 m a.s.l.) during the three-month episode are 2.75 and 0.34 kg S(N) ha(-1), which agree well with the observed wet deposition fluxes of 2.42 and 0.39 kg S(N) ha(-1), respectively. Temporal variations in the weekly deposition fluxes at LL are also well predicted. Wet deposition flux of NH4(+) at LL is over-predicted by approximately a factor of 3 (1.60 kg N ha(-1)vs. 0.56 kg N ha(-1)), likely due to missing alkaline earth cations such as Ca(2+) in the current CMAQ simulations. Predicted wet deposition fluxes are also in general agreement with observations at four Acid Deposition Monitoring Network in East Asia (EANET) sites in western China. Predicted dry deposition fluxes of SO4(2-) (including gas deposition of SO2) and NO3(-) (including gas deposition of HNO3) are 0.12 and 0.12 kg S(N) h a(-1) at LL and 0.07 and 0.08 kg S(N) ha(-1) at Jiuzhaigou Bureau (JB) in JNNR, respectively, which are much lower than the corresponding wet deposition fluxes. Dry deposition flux of NH4(+) (including gas deposition of NH3) is 0.21 kg N ha(-1) at LL, and is also much lower than the predicted wet deposition flux. For both dry and wet deposition fluxes, predictions

  3. Global cloud and precipitation chemistry and wet deposition: tropospheric model simulations with ECHAM5/MESSy1

    Directory of Open Access Journals (Sweden)

    J. Lelieveld

    2007-05-01

    Full Text Available The representation of cloud and precipitation chemistry and subsequent wet deposition of trace constituents in global atmospheric chemistry models is associated with large uncertainties. To improve the simulated trace gas distributions we apply the new submodel SCAV, which includes detailed cloud and precipitation chemistry and present results of the atmospheric chemistry general circulation model ECHAM5/MESSy1. A good agreement with observed wet deposition fluxes for species causing acid rain is obtained. The new scheme enables prognostic calculations of the pH of clouds and precipitation, and these results are also in accordance with observations. We address the influence of detailed cloud and precipitation chemistry on trace constituents based on sensitivity simulations. The results confirm previous results from regional scale and box models, and we extend the analysis to the role of aqueous phase chemistry on the global scale. Some species are directly affected through multiphase removal processes, and many also indirectly through changes in oxidant concentrations, which in turn have an impact on the species lifetime. While the overall effect on tropospheric ozone is relatively small (3 can reach ≈20%, and several important compounds (e.g., H2O2, HCHO are substantially depleted by clouds and precipitation.

  4. A novel multi-temporal approach to wet snow retrieval with Sentinel-1 images (Conference Presentation)

    Science.gov (United States)

    Marin, Carlo; Callegari, Mattia; Notarnicola, Claudia

    2016-10-01

    Snow is one of the most relevant natural water resources present in nature. It stores water in winter and releases it in spring during the melting season. Monitoring snow cover and its variability is thus of great importance for a proactive management of water-resources. Of particular interest is the identification of snowmelt processes, which could significantly support water administration, flood prediction and prevention. In the past years, remote sensing has demonstrated to be an essential tool for providing accurate inputs to hydrological models concerning the spatial and temporal variability of snow. Even though the analysis of snow pack can be conducted in the visible, near-infrared and short-wave infrared spectrum, the presence of clouds during the melting season, which may be pervasive in some parts of the World (e.g., polar regions), renders impossible the regular acquisition of information needed for the operational purposes. Therefore, the use of the microwave sensors, which signal can penetrate the clouds, can be an asset for the detection of snow proprieties. In particular, the SAR images have demonstrated to be effective and robust measurements to identify the wet snow. Among the several methods presented in the literature, the best results in wet snow mapping have been achieved by the bi-temporal change detection approach proposed by Nagler and Rott [1], or its slight improvements presented afterwards (e.g., [2]). Nonetheless, with the introduction of the Sentinel-1 by ESA, which provides free-of-charge SAR images every 6 days over the same geographical area with a resolution of 20m, the scientists have the opportunity to better investigate and improve the state-of-the-art methods for wet snow detection. In this work, we propose a novel method based on a supervised learning approach able to exploit both the experience of the state-of-the-art algorithms and the high multi-temporal information provided by the Sentinel-1 data. In detail, this is done

  5. Airmass Trajectories and Long Range Transport of Pollutants: Review of Wet Deposition Scenario in South Asia

    Directory of Open Access Journals (Sweden)

    Umesh Kulshrestha

    2014-01-01

    Full Text Available This paper presents a review of airmass trajectories and their role in air pollution transport. It describes the concept, history, and basic calculation of air trajectories citing various trajectory models used worldwide. It highlights various areas of trajectory applications and errors associated with trajectory calculations. South Asian region receives airmasses from Europe, Middle East, Africa, and Indian Ocean, and so forth, depending upon the season. These airmasses are responsible for export and import of pollutants depositing in nearby states. Trajectory analysis revealed that soil is contributed by the dust storms coming from Oman through Gulf and Iran, while most of black carbon (BC sources are located in India. A detailed review of trajectories associated with wet deposition events indicated that airmasses coming from Europe and Middle East carry high concentration of acidic pollutants which are deposited in Himalayan ranges. Similarly, trajectory analysis revealed that acidic pollutants from continental anthropogenic sources are transported to an ecosensitive site in Western Ghats in India and the outward fluxes of anthropogenic activities of Indo-Gangetic region are transported towards Bay of Bengal. Hence, transboundary and long range transport of pollutants are very important issues in South Asia which need immediate attention of scientists and policy makers.

  6. Assessment of atmospheric trace metal deposition in urban environments using direct and indirect measurement methodology and contributions from wet and dry depositions

    Science.gov (United States)

    Omrani, Mehrazin; Ruban, Véronique; Ruban, Gwenaël; Lamprea, Katerine

    2017-11-01

    Bulk Atmospheric Deposition (BAD), Wet Atmospheric Deposition (WAD) and Dry Atmospheric Deposition (DAD) were all measured within an urban residential area in Nantes (France) over a 9-month period (27 February - 10 December 2014). The objectives of this study were to compare 2 methods for measuring dry and wet atmospheric depositions in the urban environment (DAD and WAD: direct method; BAD and WAD: indirect one), and to characterize as well the variations and relative contributions of these depositions. Trace metals (As, Cd, Cr, Cu, Ni, Pt and V) were used to carry out these comparison and quantification. BAD was collected with two open polyethylene containers (72 × 54 × 21 cm), while WAD was collected by means of an automated rainwater collector and DAD was determined from both air measurements (recorded by an air sampler) and 7Be deposition velocities. The comparison based on a detailed evaluation of uncertainties showed a significant difference between the direct and indirect methods. Dry and wet depositions varied widely from one month to the next. Zn and Cu were the most abundant elements in both dry and wet depositions. The mean contribution of DAD to the bulk atmospheric deposition during this 9-month study was significant for Zn, Cu and V (about 25%) as well as for Pb (approx. 60%). For this relatively unpolluted urban residential catchment, the contribution of atmospheric deposition to global load at the catchment outlet was low, between 10% and 20% for Zn, Cu, V and Pb, 25% for Cr and about 30% for Ni. For other urban sites exhibiting high atmospheric pollution however, the atmospheric contribution to the global pollution load could be much greater. An accurate and representative estimation of DAD thus proves critical.

  7. Continental-scale assessment of long-term trends in wet deposition trajectories: Role of anthropogenic and hydro-climatic drivers

    Science.gov (United States)

    Park, J.; Gall, H. E.; Niyogi, D.; Rao, S.

    2012-12-01

    The global trend of increased urbanization, and associated increased intensity of energy and material consumption and waste emissions, has contributed to shifts in the trajectories of aquatic, terrestrial, and atmospheric environments. Here, we focus on continental-scale spatiotemporal patterns in two atmospheric constituents (nitrate and sulfate), whose global biogeochemical cycles have been dramatically altered by emissions from mobile and fixed sources in urbanized and industrialized regions. The observed patterns in wet deposition fluxes of nitrate and sulfate are controlled by (1) natural hydro-climatic forcing, and (2) anthropogenic forcing (emissions and regulatory control), both of which are characterized by stochasticity and non-stationarity. We examine long-term wet deposition records in the U.S., Europe, and East Asia to evaluate how anthropogenic and natural forcing factors jointly contributed to the shifting temporal patterns of wet deposition fluxes at continental scales. These data offer clear evidence for successful implementation of regulatory controls and widespread adoption of technologies contributed to improving water quality and mitigation of adverse ecological impacts. We developed a stochastic model to project the future trajectories of wet deposition fluxes in emerging countries with fast growing urban areas. The model generates ellipses within which projected wet deposition flux trajectories are inscribed, similar to the trends in observational data. The shape of the ellipses provides information regarding the relative dominance of anthropogenic (e.g., industrial and urban emissions) versus hydro-climatic drivers (e.g., rainfall patterns, aridity index). Our analysis facilitates projections of the trajectory shift as a result of urbanization and other land-use changes, climate change, and regulatory enforcement. We use these observed data and the model to project likely trajectories for rapidly developing countries (BRIC), with a

  8. Towards a new daily in-situ precipitation data set supporting parameterization of wet-deposition of CTBT relevant radionuclides

    Science.gov (United States)

    Becker, A.; Ceranna, L.; Ross, O.; Schneider, U.; Meyer-Christoffer, A.; Ziese, M.; Lehner, K.; Rudolf, B.

    2012-04-01

    As contribution to the World Climate Research Program (WCRP) and in support of the Global Climate Observing System (GCOS) of the World Meteorological Organization (WMO), the Deutscher Wetterdienst (DWD) operates the Global Precipitation Climatology Centre (GPCC). The GPCC re-analysis and near-real time monitoring products are recognized world-wide as the most reliable global data set on rain-gauge based (in-situ) precipitation measurements. The GPCC Monitoring Product (Schneider et al, 2011; Becker et al. 2012, Ziese et al, EGU2012-5442) is available two months after the fact based on the data gathered while listening to the GTS to fetch the SYNOP and CLIMAT messages. This product serves also the reference data to calibrate satellite based precipitation measurements yielding the Global Precipitation Climatology Project (GPCP) data set (Huffmann et al., 2009). The quickest GPCC product is the First Guess version of the GPCC Monitoring Product being available already 3-5 days after the month regarded. Both, the GPCC and the GPCP products bear the capability to serve as data base for the computational light-weight post processing of the wet deposition impact on the radionuclide (RN) monitoring capability of the CTBT network (Wotawa et al., 2009) on the regional and global scale, respectively. This is of major importance any time, a reliable quantitative assessment of the source-receptor sensitivity is needed, e.g. for the analysis of isotopic ratios. Actually the wet deposition recognition is a prerequisite if ratios of particulate and noble gas measurements come into play. This is so far a quite unexplored field of investigation, but would alleviate the clearance of several apparently CTBT relevant detections, encountered in the past, as bogus and provide an assessment for the so far overestimation of the RN detection capability of the CTBT network. Besides the climatological kind of wet deposition assessment for threshold monitoring purposes, there are also singular

  9. Radiocaesium activity in rape oil and in rape cake after a wet deposition event

    Energy Technology Data Exchange (ETDEWEB)

    Chaiko, Y.; Rappe-George, M.; Bengtsson, S. [Department of Soil and Environment (Sweden)

    2014-07-01

    After a release of radionuclides in agricultural areas there can be concerns on the levels of radionuclides in food products produced. The uptake of radionuclides via the above ground plant parts is a very important transport route into the food chain for humans as caesium is relatively mobile inside plants. In the production of rape oil the use of a processing factor (Pf) is used to estimate the activity concentration of radioactivity in the final oil product based on the activity concentration in rape seeds. The processing factor has been estimated to be 0.004 for caesium in rape oil by IAEA, and is based on a limited numbers of studies (1). In this project we analysed the activity concentration of radiocaesium ({sup 134}Cs) in rape oil and in rape cake from rape seeds contaminated after a wet deposition event with {sup 134}Cs. With the information of activity concentration of {sup 134}Cs in rape oil and in rape cake, we calculated the Pf-value and confirm or suggest new enhanced Pf-value. We analysed the activity concentration of {sup 134}Cs in rape oil and in rape cake from spring oilseed rape seeds (Brassica napus L.) that had been contaminated experimentally by wet deposited {sup 134}Cs in an earlier experiment by Bengtsson et al. (2013). The estimation of activity concentration of {sup 134}Cs in rape oil and in rape cake was achieved by performing extraction of the oil (and other extractable compounds) from the seeds based on the Randall extraction method (Randall, 1974) using petroleum ether as extraction chemical. The extracted oil and the rape cake samples were weighed and the activity concentration was measured with High-Purity Germanium (HPGe) detectors. Pf-values were calculated by dividing the measured activity concentration in rape oil after extraction by the activity concentration in oilseed rape seeds before extraction. Results from the present study will be presented at the international conference on radioecology and environmental radioactivity

  10. Dry and wet "deposition" studies of the degradation of cement mortars

    Directory of Open Access Journals (Sweden)

    Martínez-Ramírez, S.

    1998-06-01

    Full Text Available The reaction of portland cement mortars with SO2 gaseous pollutant and artificial 'acid rain' solution has been examined using laboratory exposure chambers, with realistic presentation rates of pollutants. The mortar were previously carbonated to produce superficial carbonation. Two mortars with different w/c ratio and hence specific surface were prepared and exposed into the chambers. For dry deposition of SO2 pollutant gas, the important roles of water and water plus oxidant in increasing chemical reaction are readily revealed. Further, accessible porosity also increases reaction through increased times of reaction of pollutant with the mortars. Interestingly, in the absence of deliberate surface wetting, the presence of oxidant, ozone, leads to a reduction in the already limited extent of reaction. Wet deposition studies using artificial 'acid rain' solution result in gypsum formation, which is more extensive for mortars of increased w/c ratios.

    Se han realizado ensayos de laboratorio de simulación de los procesos ambientales de "deposición" seca y húmeda sobre morteros de cemento portland, estudiándose las reacciones que se producen con el contaminante SO2 ("deposición" seca y la disolución de 'lluvia acida' ("deposición" húmeda. Los morteros de cemento se carbonataron para favorecer la carbonatación superficial de los mismos. Se prepararon morteros con dos relaciones a/c con el fin de estudiar la influencia que la variable superficie específica tenía en el proceso de deterioro de dichos materiales. En los estudios de deposición seca con SO2 como gas agresivo se ha visto la importancia que el agua y el agua junto a un oxidante tienen en la reacción del contaminante con los componentes del mortero. La superficie específica Juega un papel importante, ya que al aumentar, aumenta la reacción con el contaminante. La reacción en presencia de oxidante, (SO2+O3

  11. Modeling wet deposition and concentration of inorganics over Northeast Asia with MRI-PM/c

    Directory of Open Access Journals (Sweden)

    M. Kajino

    2012-11-01

    Full Text Available We conducted a regional-scale simulation over Northeast Asia for the year 2006 using an aerosol chemical transport model, with time-varying lateral and upper boundary concentrations of gaseous species predicted by a global stratospheric and tropospheric chemistry-climate model. The present one-way nested global-through-regional-scale model is named the Meteorological Research Institute–Passive-tracers Model system for atmospheric Chemistry (MRI-PM/c. We evaluated the model's performance with respect to the major anthropogenic and natural inorganic components, SO42−, NH4+, NO3, Na+ and Ca2+ in the air, rain and snow measured at the Acid Deposition Monitoring Network in East Asia (EANET stations. Statistical analysis showed that approximately 40–50 % and 70–80 % of simulated concentration and wet deposition of SO42−, NH4+, NO3and Ca2+ are within factors of 2 and 5 of the observations, respectively. The prediction of the sea-salt originated component Na+ was not successful at near-coastal stations (where the distance from the coast ranged from 150 to 700 m, because the model grid resolution (Δx=60 km is too coarse to resolve it. The simulated Na+ in precipitation was significantly underestimated by up to a factor of 30.

  12. Atmospheric wet deposition of mercury and other trace elements in Pensacola, Florida

    Directory of Open Access Journals (Sweden)

    W. M. Landing

    2010-05-01

    Full Text Available In an effort to understand and quantify the impact of local, regional, and far-distant atmospheric mercury sources to rainfall mercury deposition in the Pensacola, Florida watershed, a program of event-based rainfall sampling was started in late 2004. Modified Aerochem-Metrics wet/dry rainfall samplers were deployed at three sites in the region around the Crist coal-fired power plant and event-based samples were collected continuously for three years. Samples were analyzed for total Hg and a suite of trace elements including Al, As, Ba, Bi, Cd, Ce, Co, Cr, Cs, Cu, Fe, Ga, La, Li, Mg, Mn, Na, Nb, Ni, P, Pb, Sb, Se, Si, Sn, Sr, Th, U, V, and Zn. Nutrients (ammonia and nitrate and major anions (chloride and sulfate were also measured on each sample. Multivariate statistical methods were used to sort these tracers into factors that represent potential source categories contributing to the rainfall chemistry. As, Hg, Sb, Se, Sn, and non sea-salt sulfate were all significantly correlated (R>0.6 with one factor which we interpret as an anthropogenic source term reflecting input from coal combustion throughout the southeastern US. Using ratios of total Hg to volatile elements, we estimate that 22–33% of the rainfall Hg results from coal combustion in the southeastern US with the majority coming from the global background.

  13. Interception of wet deposited atmospheric pollutants by herbaceous vegetation: Data review and modelling

    Energy Technology Data Exchange (ETDEWEB)

    Gonze, M.-A., E-mail: marc-andre.gonze@irsn.fr; Sy, M.M.

    2016-09-15

    Better understanding and predicting interception of wet deposited pollutants by vegetation remains a key issue in risk assessment studies of atmospheric pollution. We develop different alternative models, following either empirical or semi-mechanistic descriptions, on the basis of an exhaustive dataset consisting of 440 observations obtained in controlled experiments, from 1970 to 2014, for a wide variety of herbaceous plants, radioactive substances and rainfall conditions. The predictive performances of the models and the uncertainty/variability of the parameters are evaluated under Hierarchical Bayesian modelling framework. It is demonstrated that the variability of the interception fraction is satisfactorily explained and quite accurately modelled by a process-based alternative in which absorption of ionic substances onto the foliage surfaces is determined by their electrical valence. Under this assumption, the 95% credible interval of the predicted interception fraction encompasses 81% of the observations, including situations where either plant biomass or rainfall intensity are unknown. This novel approach is a serious candidate to challenge existing empirical relationships in radiological or chemical risk assessment tools. - Highlights: • Literature data on the interception of atmospheric pollutants by herbs were reviewed • Predictive models were developed and evaluated in the Bayesian modelling framework • Sensitivity of interception to environmental conditions was satisfactorily explained • 81% of the observations were satisfactorily predicted by a semi-mechanistic model • This model challenges empirical relationships currently used in risk assessment tools.

  14. Characterization of Wet and Dry Deposition in the Downwind of Industrial Sources in a Dry Tropical Area

    Directory of Open Access Journals (Sweden)

    Raj K. Singh

    2001-01-01

    Full Text Available An atmospheric deposition study was conducted in the downwind of Shaktinagar Thermal Power Plant (STPP, Renusagar Thermal Power Plant (RTPP, and Anpara Thermal Power Plant (ATPP, at Singrauli region, Uttar Pradesh (UP, India to characterize dry and wet deposition in relation to different pollution loading. During the study period, dry and wet depositions and levels of gaseous pollutants (SO2 and NO2 were estimated across the sites. Dry deposition was collected on a monthly basis and wet deposition on an event basis. Depositions were analyzed for pH, nitrate (NO3�, ammonium (NH4+, and sulphate (SO42� contents. Dry deposition rate both collected as clearfall and throughfall varied between 0.15 to 2.28 and 0.33 to 3.48 g m�2 day�1, respectively, at control and maximally polluted sites. The pH of dry deposition varied from 5.81 to 6.89 during winter and 6.09 to 7.02 during summer across the sites. During the rainy season, the mean pH of clear wet deposition varied from 6.56 to 7.04 and throughfall varied from 6.81 to 7.22. The concentrations of NO2 and SO2 pollutants were highest during the winter season. Mean SO2 concentrations varied from 18 to 75 �g m�3 at control and differently polluted sites during the winter season. The variation in NO2 concentrations did not show a pattern similar to that of SO2. The highest NO2 concentration during the winter season was 50 �g m�3, observed near RTPP. NO2 concentration did not show much variation among different sites, suggesting that the sources of NO2 emission are evenly distributed along the sites. The concentrations of NH4+, NO3�, and SO42� ions in dry deposition were found to be higher in summer as compared to the winter season. In dry deposition (clearfall the concentrations of NH4+, NO3�, and SO42� varied from 0.13 to 1.0, 0.81 to 1.95, and 0.82 to 3.27 mg l�1, respectively, during winter. In wet deposition (clearfall, the above varied from 0.14 to 0.74, 0.81 to 1.82, and 0

  15. Wet deposition of fission-product isotopes to North America from the Fukushima Dai-ichi incident, March 2011

    Science.gov (United States)

    Wetherbee, Gregory A.; Gay, David A.; Debey, Timothy M.; Lehmann, Christopher M.B.; Nilles, Mark A.

    2012-01-01

    Using the infrastructure of the National Atmospheric Deposition Program (NADP), numerous measurements of radionuclide wet deposition over North America were made for 167 NADP sites before and after the Fukushima Dai-ichi Nuclear Power Station incident of March 12, 2011. For the period from March 8 through April 5, 2011, wet-only precipitation samples were collected by NADP and analyzed for fission-product isotopes within whole-water and filterable solid samples by the United States Geological Survey using gamma spectrometry. Variable amounts of 131I, 134Cs, or 137Cs were measured at approximately 21% of sampled NADP sites distributed widely across the contiguous United States and Alaska. Calculated 1- to 2-week individual radionuclide deposition fluxes ranged from 0.47 to 5100 Becquerels per square meter during the sampling period. Wet deposition activity was small compared to measured activity already present in U.S. soil. NADP networks responded to this complex disaster, and provided scientifically valid measurements that are comparable and complementary to other networks in North America and Europe.

  16. Wet deposition of fission-product isotopes to North America from the Fukushima Dai-ichi incident, March 2011.

    Science.gov (United States)

    Wetherbee, Gregory A; Gay, David A; Debey, Timothy M; Lehmann, Christopher M B; Nilles, Mark A

    2012-03-06

    Using the infrastructure of the National Atmospheric Deposition Program (NADP), numerous measurements of radionuclide wet deposition over North America were made for 167 NADP sites before and after the Fukushima Dai-ichi Nuclear Power Station incident of March 12, 2011. For the period from March 8 through April 5, 2011, wet-only precipitation samples were collected by NADP and analyzed for fission-product isotopes within whole-water and filterable solid samples by the United States Geological Survey using gamma spectrometry. Variable amounts of (131)I, (134)Cs, or (137)Cs were measured at approximately 21% of sampled NADP sites distributed widely across the contiguous United States and Alaska. Calculated 1- to 2-week individual radionuclide deposition fluxes ranged from 0.47 to 5100 Becquerels per square meter during the sampling period. Wet deposition activity was small compared to measured activity already present in U.S. soil. NADP networks responded to this complex disaster, and provided scientifically valid measurements that are comparable and complementary to other networks in North America and Europe.

  17. The effect of dry and wet deposition of condensable vapors on secondary organic aerosols concentrations over the continental US

    Science.gov (United States)

    Knote, C.; Hodzic, A.; Jimenez, J. L.

    2015-01-01

    The effect of dry and wet deposition of semi-volatile organic compounds (SVOCs) in the gas phase on the concentrations of secondary organic aerosol (SOA) is reassessed using recently derived water solubility information. The water solubility of SVOCs was implemented as a function of their volatility distribution within the WRF-Chem regional chemistry transport model, and simulations were carried out over the continental United States for the year 2010. Results show that including dry and wet removal of gas-phase SVOCs reduces annual average surface concentrations of anthropogenic and biogenic SOA by 48 and 63% respectively over the continental US. Dry deposition of gas-phase SVOCs is found to be more effective than wet deposition in reducing SOA concentrations (-40 vs. -8% for anthropogenics, and -52 vs. -11% for biogenics). Reductions for biogenic SOA are found to be higher due to the higher water solubility of biogenic SVOCs. The majority of the total mass of SVOC + SOA is actually deposited via the gas phase (61% for anthropogenics and 76% for biogenics). Results are sensitive to assumptions made in the dry deposition scheme, but gas-phase deposition of SVOCs remains crucial even under conservative estimates. Considering reactivity of gas-phase SVOCs in the dry deposition scheme was found to be negligible. Further sensitivity studies where we reduce the volatility of organic matter show that consideration of gas-phase SVOC removal still reduces average SOA concentrations by 31% on average. We consider this a lower bound for the effect of gas-phase SVOC removal on SOA concentrations. A saturation effect is observed for Henry's law constants above 108 M atm-1, suggesting an upper bound of reductions in surface level SOA concentrations by 60% through removal of gas-phase SVOCs. Other models that do not consider dry and wet removal of gas-phase SVOCs would hence overestimate SOA concentrations by roughly 50%. Assumptions about the water solubility of SVOCs made in

  18. The effect of dry and wet deposition of condensable vapors on secondary organic aerosols concentrations over the continental US

    Directory of Open Access Journals (Sweden)

    C. Knote

    2015-01-01

    Full Text Available The effect of dry and wet deposition of semi-volatile organic compounds (SVOCs in the gas phase on the concentrations of secondary organic aerosol (SOA is reassessed using recently derived water solubility information. The water solubility of SVOCs was implemented as a function of their volatility distribution within the WRF-Chem regional chemistry transport model, and simulations were carried out over the continental United States for the year 2010. Results show that including dry and wet removal of gas-phase SVOCs reduces annual average surface concentrations of anthropogenic and biogenic SOA by 48 and 63% respectively over the continental US. Dry deposition of gas-phase SVOCs is found to be more effective than wet deposition in reducing SOA concentrations (−40 vs. −8% for anthropogenics, and −52 vs. −11% for biogenics. Reductions for biogenic SOA are found to be higher due to the higher water solubility of biogenic SVOCs. The majority of the total mass of SVOC + SOA is actually deposited via the gas phase (61% for anthropogenics and 76% for biogenics. Results are sensitive to assumptions made in the dry deposition scheme, but gas-phase deposition of SVOCs remains crucial even under conservative estimates. Considering reactivity of gas-phase SVOCs in the dry deposition scheme was found to be negligible. Further sensitivity studies where we reduce the volatility of organic matter show that consideration of gas-phase SVOC removal still reduces average SOA concentrations by 31% on average. We consider this a lower bound for the effect of gas-phase SVOC removal on SOA concentrations. A saturation effect is observed for Henry's law constants above 108 M atm−1, suggesting an upper bound of reductions in surface level SOA concentrations by 60% through removal of gas-phase SVOCs. Other models that do not consider dry and wet removal of gas-phase SVOCs would hence overestimate SOA concentrations by roughly 50%. Assumptions about the water

  19. Spatial patterns and temporal changes in atmospheric-mercury deposition for the midwestern USA, 2001–2016

    Science.gov (United States)

    Risch, Martin R.; Kenski, Donna M.

    2018-01-01

    Spatial patterns and temporal changes in atmospheric-mercury (Hg) deposition were examined in a five-state study area in the Midwestern USA where 32% of the stationary sources of anthropogenic Hg emissions in the continental USA were located. An extensive monitoring record for wet and dry Hg deposition was compiled for 2001–2016, including 4666 weekly precipitation samples at 13 sites and 27 annual litterfall-Hg samples at 7 sites. This study is the first to examine these Hg data for the Midwestern USA. The median annual precipitation-Hg deposition at the study sites was 10.4 micrograms per square meter per year (ug/m2/year) and ranged from 5.8 ug/m2/year to 15.0 ug/m2/year. The median annual Hg concentration was 9.4 ng/L. Annual litterfall-Hg deposition had a median of 16.1 ug/m2/year and ranged from 9.7 to 23.4 ug/m2/year. Isopleth maps of annual precipitation-Hg deposition indicated a recurring spatial pattern similar to one revealed by statistical analysis of weekly precipitation-Hg deposition. In that pattern, high Hg deposition in southeastern Indiana was present each year, frequently extending to southern Illinois. Most of central Indiana and central Illinois had similar Hg deposition. Areas with comparatively lower annual Hg deposition were observed in Michigan and Ohio for many years and frequently included part of northern Indiana. The area in southern Indiana where high Hg deposition predominated had the highest number of extreme episodes of weekly Hg deposition delivering up to 15% of the annual Hg load from precipitation in a single week. Modeled 48-h back trajectories indicated air masses for these episodes often arrived from the south and southwest, crossing numerous stationary sources of Hg emissions releasing from 23 to more than 300 kg Hg per year. This analysis suggests that local and regional, rather than exclusively continental or global Hg emissions were likely contributing to the extreme episodes and at least in part, to the spatial

  20. Size distribution of airborne particle-bound polybrominated diphenyl ethers and its implications for dry and wet deposition.

    Science.gov (United States)

    Luo, Pei; Ni, Hong-Gang; Bao, Lian-Jun; Li, Shao-Meng; Zeng, Eddy Y

    2014-12-02

    Size distribution of particles in part dictates the environmental behavior of particle-bound organic pollutants in the atmosphere. The present study was conducted to examine the potential mechanisms responsible for the distribution of organic pollutants in size fractionated particles and their environmental implications, using an e-waste recycling zone in South China as a case study. Size-fractionated atmospheric particles were collected at the heights of 1.5, 5, and 20 m near two residential apartments and analyzed for polybrominated diphenyl ethers (PBDEs). The concentrations of particle-bound ΣPBDE (sum of 18 PBDE congeners) were significantly greater at 5 and 20 m than those at 1.5 m. The size-fractionated distributions of airborne ΣPBDE displayed trimodal peaks in 0.10–0.18, 1.8–3.2, and 10–18 μm at 1.5 m but only an unimodal peak in 1.0–1.8 μm at 20 m height. Emission sources, resuspension of dust and soil, and volatility of PBDEs were important factors influencing the size distribution of particle-bound PBDEs. The dry deposition fluxes of particle-bound PBDE estimated from the measured data in the present study were approximately twice the estimated wet deposition fluxes, with a total deposition flux of 3000 ng m(–2) d(–1). The relative contributions of particles to dry and wet deposition fluxes were also size-dependent, e.g., coarse (aerodynamic diameters (Dp) > 1.8 μm) and fine (Dp < 1.8 μm) particles dominated the dry and wet deposition fluxes of PBDEs, respectively.

  1. Wet deposition of sulfur and nitrogen in Jiuzhaigou National Nature Reserve, Sichuan, China during 2015-2016: Possible effects from regional emission reduction and local tourist activities.

    Science.gov (United States)

    Qiao, Xue; Du, Jie; Kota, Sri Harsha; Ying, Qi; Xiao, Weiyang; Tang, Ya

    2018-02-01

    In order to understand the impacts of regional emission changes and local tourism on sulfur and nitrogen wet deposition in Jiuzhaigou National Nature Reserve of southwestern China, wet deposition was monitored at a background site (Rize) and a tourist-affected site (PE: park entrance) in the reserve during 2015-2016. The observation data were compared between Rize and PE and between 2010-2011 and 2015-2016 monitoring campaigns. Also, the observation data were used in the Positive Matrix Factorization (PMF) model to identify the major sources of sulfur and nitrogen wet deposition. The results show that although local tourism emissions had considerable contributions to NH 4 + , NO 2 - , NO 3 - , and SO 4 2- concentrations in wet deposition (p reserve are needed to confirm this. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Wet deposition of mercury in Qingdao, a coastal urban city in China: Concentrations, fluxes, and influencing factors

    Science.gov (United States)

    Chen, Lufeng; Li, Yanbin; Liu, Chang; Guo, Lina; Wang, Xiulin

    2018-02-01

    Mercury (Hg) is a global pollutant of public concern because of its high toxicity and capability for worldwide distribution via long-range atmospheric transportation. Wet atmospheric deposition is an important source of Hg in both terrestrial and aquatic environments. Concentrations of various Hg species in precipitation were monitored from March 2016 to February 2017 in a coastal urban area of Qingdao, and their wet deposition fluxes were estimated. The results showed that the volume-weighted mean (VWM) concentrations of total mercury (THg), reactive mercury (RHg), dissolved THg (DTHg), particulate THg (PTHg), total methylmercury (TMeHg), and dissolved and particulate MeHg (DMeHg and PMeHg) in Qingdao's precipitation were 13.6, 1.5, 5.4, 8.2, 0.38, 0.15, and 0.22 ng L-1, respectively, and their annual deposition fluxes were estimated to be 5703.0 (THg), 666.6 (RHg), 2304.0 (DTHg), 3470.4 (PTHg), 161.6 (TMeHg), 64.0 (DMeHg), and 95.7 (PMeHg) ng m-2 y-1, respectively. A relatively high proportion of MeHg in THg was observed in precipitation (3.0 ± 2.6%) possibly due to higher methylation and contributions from an oceanic source to MeHg in the precipitation. Obvious seasonal variations in Hg concentrations and deposition fluxes were observed in the precipitation in Qingdao. Correlation analyses and multiple regression analyses showed that SO2, pH, and NO3- were the controlling factors for THg in precipitation, whereas the MeHg concentration was primarily controlled by the SO2, WS, Cl-, and THg concentrations. PM2.5 and Cl- were the major controlling factors for PMeHg/TMeHg, whereas the TMeHg/THg ratio was mainly influenced by Cl-. The THg and MeHg fluxes were primarily controlled by precipitation, whereas Cl- was also an important factor for the MeHg wet deposition flux. The results of a 72-h backward trajectory analysis in the study region with the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model indicated that Hg deposition in Qingdao mainly

  3. Measurements and estimates of leaf wetness over agricultural grassland for dry deposition modeling of trace gases

    NARCIS (Netherlands)

    Wichink Kruit, R.J.; Jacobs, A.F.G.; Holtslag, A.A.M.

    2008-01-01

    Leaf wetness is an important and frequent phenomenon for the surface¿atmosphere exchange of some atmospheric trace gases that are well soluble in water, such as ammonia (NH3 and SO2), as well as for plant disease epidemiology. This study shows a comparison of two different techniques to measure leaf

  4. Wet deposition of air pollution at southwest monsoon outbreak and its impact on groundwater resources of Greater Kochi region

    Digital Repository Service at National Institute of Oceanography (India)

    Joseph, T.; Nair, M.; Balachandran, K.K.; Nair, K.K.C.

    Hydrology and Water Resources, Sherif, Singh & AI-Rashed (eds) © 2003 Swels & Zeilfinger, Lisse, ISBN 90 5809 548 7 Wet deposition of air pollution at southwest monsoon outbreak and its impact on groundwater resources of Greater Kochi Region Thresiamma... and pH was measured on the spot. The samples for the dissolved nutri ents were frozen and stored. The analyses for dissolved nutrients were performed by the standard methods used for the seawater analysis. All the samples were ana lyzed within 12 hours...

  5. Coalescence of fog droplets: Differential fog water deposition on wet and dry forest canopies

    Science.gov (United States)

    Tobón, C.; Barrero, J.

    2010-07-01

    The Páramo ecosystem is a high-altitude (2800 - 4500 masl), natural ecosystems which comprises approximately 42000 km2, extending across the Andes from north of Peru, Ecuador, Colombia and western part of Venezuela. Andean páramos are widely considered to be prime suppliers of large volumes of high-quality water for large cities and for hydropower production. As páramos tend to be subjected to persistent fog incidence, fog interception by the vegetation is a common process in these ecosystems, representing not only an extra input of water to the ecosystem but also to suppress evaporation. In this process, small drops of water, transported by the wind, are captured by the surfaces of the vegetation, acting as physical obstacles to the flow of fog. These drops condense in the exposed surfaces and drip towards the ground or evaporate from the surfaces. The quantification of the magnitude of these processes is important for the quantification of the water balance of river basins where these types of ecosystems exist. Although the great hydrological importance of fog in montane tropical ecosystems little is known about its physical principles related to the interception of fog by physical barriers as vegetation, notably the differential behaviour of a wet and dry vegetation in the efficiency of capturing water from the fog. To characterize and quantify this efficiency of páramo vegetation in capturing water from the fog, during wet and dry canopy conditions, an experimental design was set up at the Páramo de Chingaza (Colombia) where paired samples of espeletia branches (dry and wet) were exposed to different fog events, and at the same time Juvik cylinders were exposed by the side of the experimental site, to measured fog inputs. Cylinders were also paired (wet and dry) at the beginning of the experiments. Results indicated that exposed wet and dry samples have a significant difference on the magnitude of water intercepted from the fog, being, in average, the wet

  6. Characterisation of nutrients wet deposition under influence of Saharan dust at Puerto-Rico in Caribbean Sea

    Science.gov (United States)

    Desboeufs, Karine; Formenti, Paola; Triquet, Sylvain; Laurent, Benoit; Denjean, Cyrielle; Gutteriez-Moreno, Ian E.; Mayol-Bracero, Olga L.

    2015-04-01

    Large quantities of African dust are carried across the North Atlantic toward the Caribbean every summer by Trade Winds. Atmospheric deposition of dust aerosols, and in particular wet deposition, is widely acknowledged to be the major delivery pathway for nutrients to ocean ecosystems, as iron, phosphorus and various nitrogen species. The deposition of this dustis so known to have an important impact on biogeochemical processes in the Tropical and Western Atlantic Ocean and Caribbean including Puerto-Rico. However, very few data exists on the chemical composition in nutrients in dusty rain in this region. In the framework of the Dust-ATTAcK project, rainwater was collected at the natural reserve of Cape San Juan (CSJ) (18.38°N, 65.62°W) in Puerto-Ricobetween 20 June 2012 and 12 July 2012 during thedusty period. A total of 7 rainwater events were sampled during various dust plumes. Complementary chemical analyses on aerosols in suspension was also determined during the campaign. The results on dust composition showed that no mixing with anthropogenic material was observed, confirming dust aerosols were the major particles incorporated in rain samples. The partitioning between soluble and particulate nutrients in rain samples showed that phosphorous solubility ranged from 30 and 80%. The average Fe solubility was around 0.5%, in agreement with Fe solubility observed in rains collected in Niger during African monsoon. That means that the high solubility measurements previously observed in Caribbean was probably due to an anthropogenic influence. Atmospheric wet deposition fluxes of soluble and total nutrients (N, P, Si, Fe, Co, Cu, Mn, Ni, Zn) to Caribbean Sea were determined. Atmospheric P and N inputs were strongly depleted relative to the stoichiometry of phytoplankton Fe, N, P and Si requirements.The nitrogen speciation was also determined and showed the predominance of ammonium form. 3-D modeling was used to estimate the spatial extend of these fluxes over the

  7. The atmospheric pollution in the area of the Goczałkowice Reservoir changes based on wet and dry deposition

    Directory of Open Access Journals (Sweden)

    Mieczysław LEŚNIOK

    2014-11-01

    Full Text Available The Goczałkowice Reservoir was formed as a result of the accumulation of waters from the Vistula River caused by the construction of the earth dam of 2980 m in length between the town of Goczałkowice-Zdrój and Zabrzeg. It is located in Subcaprathia, near the Silesian Beskids mountain range (Outer Western Carpathians. Discussed reservoir was investigated in several environmental aspects. One of those researched elements was wet and dry pollution deposition in Integrated System Supporting Management and Protection of Water Reservoir (ZiZOZap.The research on wet and dry pollution deposition was carried out at two measurement points situated on the opposite sides of the Goczałkowice Reservoir. From the east side it was a station in Goczałkowice and from the west side a station in Frelichów (fig. 1.  The location of points allowed to assess influence of air masses from different directions and define sources of the pollutants.

  8. Analyses of NOx and wet depositions at Mühleggerkböpfl, North Tyrolean Limestone Alps.

    Science.gov (United States)

    Smidt, Stefan

    2002-01-01

    The intensive investigation site 'Mühleggerkopfl' in the North Tyrolean Limestone Alps can be classified as a clean-air area site. The mean concentrations of NOx are far below the effect-related limit value of the WHO (30 microg NOx m(-3)). The gravitational depositions in the open field (bulk deposition) ranged from 10.8 to 14.7 kg N ha(-1) a(-1) (throughfall: 11.3 to 12.3 kg N ha(-1) a(-1)) in the measuring years 1998 to 2000. Compared to these data, depositions in other forested areas of the Austrian Alps amounted to up to 30 kg N ha(-1) a(-1). The gravitational depositions (bulk deposition) alone--without considering dry and occult deposition slightly exceeded the lower limit of Critical Loads for coniferous and deciduous forests (>10 kg N ha(-1) a(-1)), but were below the Critical Loads for calcareous forests (15-20 kg N ha(-1) a(-1)).

  9. Meteorological effects on Hg wet deposition in a forested site in the Adirondack region of New York during 2000-2015

    Science.gov (United States)

    Mao, Huiting; Ye, Zhuyun; Driscoll, Charles

    2017-11-01

    An analysis of weekly measurement data of mercury (Hg) wet deposition was conducted for Huntington Wildlife Forest (HWF), a forest ecosystem in Upstate New York and a biological Hg hotspot, during 2000-2015. Annual accumulated Hg wet deposition flux was found to decrease at a rate of -0.13 μg m-2 yr-1 (2% yr-1) (p = 0.09), and volume weighted mean (VWM) Hg precipitation concentrations at -0.14 ng L-1 yr-1 (2.5% yr-1) (p = 0.00). In examining data by season, no trends were identified for the two variables. It was found that the North Atlantic Oscillation (NAO) affected Hg wet deposition predominantly in spring, as did the position of the U.S. East Coast trough in summer, which suggests different dominant mechanisms driving Hg wet deposition in different seasons. The impacts of such large scale circulation processes were facilitated via variations in precipitation amounts. This was manifested in spring 2011 with the strongest positive phase of NAO, resulting in the wettest spring with the largest Hg wet deposition flux, and in summer 2007 with the U.S. East Coast trough positioned the farthest out over the Atlantic Ocean, causing the driest summer with the lowest Hg wet deposition flux of the study period. Extreme precipitation amounts in spring could singularly drive the overall long-term trend in Hg wet deposition whereas in summer other factors could just be as important. Similar mechanisms were thought to control the long term variations of Hg wet deposition and precipitation concentrations in all seasons but summer as indicated in their significant correlation in all but summer. Atmospheric concentrations of gaseous oxidized mercury (GOM) and particulate borne mercury (PBM) at HWF over 2009-2015 hardly exhibited correlations with Hg wet deposition or precipitation concentrations. Chemical transport model simulations strongly supported efficient scavenging of oxidized Hg by precipitation resulting in the lowest concentration of GOM in the warm season despite the

  10. Drying droplet deposited on poor wetting substrate: beyond the lubrication approximation

    Science.gov (United States)

    Lebedev-Stepanov, P.; Efimov, S.; Kobelev, A.

    2017-11-01

    Evaporating sessile droplet of aqueous solution deposited on hydrophobic surface is an urgent object of theoretical modeling (evaporation dynamics, microfluidics inside the drop, particle dynamics in evaporating drop, etc) and applied researches (printing technologies, nanoparticle ensemble self-assembly processes, hydrophobic coatings, etc). Although self-assembly investigation in evaporating droplet of colloidal solution on smooth surfaces with quite acute contact angles has been widely studied recently for liquids of different properties, nanoparticles ensemble self-assembly processes in droplet deposited on hydrophobic and superhydrophobic surfaces has not received much attention up to date. This work includes the analysis of application of existing droplet evaporation models, the boundary conditions for the hydrodynamic flows on the drop surface, as well as the nanoparticle dynamics in the volume of aqueous solution droplet deposited on hydrophobic flat surface, and the dried pattern formation processes modelling.

  11. Correlation of film density and wet etch rate in hydrofluoric acid of plasma enhanced atomic layer deposited silicon nitride

    Energy Technology Data Exchange (ETDEWEB)

    Provine, J., E-mail: jprovine@stanford.edu; Schindler, Peter; Kim, Yongmin; Walch, Steve P.; Kim, Hyo Jin [Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Kim, Ki-Hyun [Manufacturing Technology Center, Samsung Electronics, Suwon, Gyeonggi-Do (Korea, Republic of); Prinz, Fritz B. [Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States)

    2016-06-15

    The continued scaling in transistors and memory elements has necessitated the development of atomic layer deposition (ALD) of silicon nitride (SiN{sub x}), particularly for use a low k dielectric spacer. One of the key material properties needed for SiN{sub x} films is a low wet etch rate (WER) in hydrofluoric (HF) acid. In this work, we report on the evaluation of multiple precursors for plasma enhanced atomic layer deposition (PEALD) of SiN{sub x} and evaluate the film’s WER in 100:1 dilutions of HF in H{sub 2}O. The remote plasma capability available in PEALD, enabled controlling the density of the SiN{sub x} film. Namely, prolonged plasma exposure made films denser which corresponded to lower WER in a systematic fashion. We determined that there is a strong correlation between WER and the density of the film that extends across multiple precursors, PEALD reactors, and a variety of process conditions. Limiting all steps in the deposition to a maximum temperature of 350 °C, it was shown to be possible to achieve a WER in PEALD SiN{sub x} of 6.1 Å/min, which is similar to WER of SiN{sub x} from LPCVD reactions at 850 °C.

  12. Fabrication of a hollow needle structure by dicing, wet etching and metal deposition

    Science.gov (United States)

    Shikida, Mitsuhiro; Hasada, Takehiko; Sato, Kazuo

    2006-10-01

    We previously proposed a novel fabrication process, which combined mechanical dicing and anisotropic wet etching, to reduce the cost of micro-electro-mechanical system devices, and fabricated various solid-type microneedle structures using this process for trans-dermal drug delivery systems. The current research involved us enhancing our previous processes by applying metal plating and using a minimum number of photolithography steps, and we fabricated a hollow-type micro-needle structure, in which a flow channel was formed at the center of the needle projection, for supplying medical solutions from the area behind the needle. We fabricated two different shaped needle structures, pyramidal and flattened needles. The height and pitch of both needle types were 120-250 µm and 230-280 µm, respectively. The developed process is useful for producing disposable microneedles for bio-medical applications.

  13. Wet acid deposition in urban areas; Deposizioni acide umide: Flussi di deposizione di specie chimiche in due siti di tipo rilievo appenninico e area urbana

    Energy Technology Data Exchange (ETDEWEB)

    Morselli, L.; Iannuccilli, A. [Bologna, Univ. (Italy). Dipt. di Chimica Industriale e dei Materiali; Barilli, L.; Olivieri, P. [ENEA, Bologna (Italy)

    1998-01-01

    This article presents the results of measurements of the water quality in acid rains, collected by a Wet and Dry Sampler from October 1994 to September 1995 at two ENEA (National Agency for New Technology, Energy and Environment) stations, Brasimone and Bologna town center, belonging to the Ridep network and characterized by different geography and different anthropogenic sources. The monitoring has allowed determining the wet deposition fluxes in both stations and highlighting the differences between two areas characterized by different typology.

  14. Gondwana's climate history inferred from the palynological record of South Africa's coal deposits: the Early Triassic wet intermezzo

    Science.gov (United States)

    Götz, Annette E.

    2013-04-01

    Permian-Triassic coals of the South African Karoo Basin play a central role in the study and interpretation of Gondwana's climate history and related vegetational changes in time and space. The palynological record of the coal-bearing formations reveals major phases of climate amelioration succeeding the Permo-Carboniferous Gondwana glaciations. Subsequent to the melting of the Dwyka ice, cold to cool-temperate climate conditions prevailed during the Early Permian and a continuous change to hot and dry climate conditions of the Late Permian and Triassic was inferred from sedimentological and palaeontological data so far. The here presented new palynological and geochemical data from the Early Triassic Molteno coal (Stormberg Group) point to a short-term switch from dry to wet climate conditions. To date, this wet intermezzo of Gondwana's early Mesozoic climate history has been overlooked in the Molteno coal of the Karoo Basin. The spore/pollen ratios, used as a proxy for humidity changes, indicate a significant climatic change corresponding to a prominent C-isotope excursion. Ongoing studies will provide a detailed palynological inventory of the Early Triassic coal deposits on an intra-Gondwanic scale, contributing to the interpretation of early Mesozoic palaeoclimates.

  15. Comparative study of CuO-CeO{sub 2} catalysts prepared by wet impregnation and deposition-precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Gurbani, A.; Ayastuy, J.L.; Gonzalez-Marcos, M.P.; Gutierrez-Ortiz, M.A. [Departamento de Ingenieria Quimica, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Bilbao 48080 (Spain); Unidad Asociada ' ' Tecnologias Quimicas para la Sostenibilidad Ambiental' ' , CSIC-UPV/EHU (Spain); Herrero, J.E.; Guil, J.M. [Instituto de Quimica Fisica ' ' Rocasolano' ' - CSIC, Madrid 28006 (Spain); Unidad Asociada ' ' Tecnologias Quimicas para la Sostenibilidad Ambiental' ' , CSIC-UPV/EHU (Spain)

    2009-01-15

    Two different preparation methods are used to synthesize wt. 7% CuO-CeO{sub 2} catalysts: a conventional wet impregnation method, and a deposition-precipitation (DP) method using Na{sub 2}CO{sub 3} as precipitating agent. Both samples are characterized by a series of techniques. CuO-CeO{sub 2} (Cu-Ce) prepared by DP shows a lower capacity to release the lattice oxygen to form CO{sub 2}. From CO-TPR results, it is demonstrated that this catalyst is not able to reduce copper clusters at low temperatures. Also, CO-TPD shows no CO{sub 2} formation. The activity results confirm the worse performance of Cu-Ce prepared by DP especially when oxygen is not in excess (PROX reaction with stoichometric oxygen). A copper particle size which is too small could create a stronger metal-support interaction, with lower Cu-Ce interface to react. (author)

  16. Nutrient gain from wet and dry atmospheric deposition and rainfall acidity in southern California chaparral.

    Science.gov (United States)

    Ellis, Barbara A; Verfaillie, Joseph R; Kummerow, Jochen

    1983-10-01

    Ionic concentration and annual deposition of NO -3 -N, NH +4 -N, Ca2+, and Mg2+ from bulk precipitation and dry atmospheric deposition were studied for one year in southern California. Data were collected from an inland chaparral site at 1,300 m elevation, 75 km from the coast. The annual depositions of NO -3 -N and NH +4 -N amounted to 96.3 and 56.0 mg m-2 ground area yr-1, respectively. The corresponding values for calcium and magnesium ions were 207.4 and 57.4 mg m-2 yr-1. The average pH of rainwater was 3.74 (range 3.37 to 4.75), thus documenting acid rain for an inland site in California, distant from urban sources of air contamination. An estimate of nitrogen gains and losses indicated that the time between recurrent chaparral fires should be about 60 years in order to maintain a balanced nitrogen budget.

  17. Trace elements and rare earth elements in wet deposition of Lijiang, Mt. Yulong region, southeastern edge of the Tibetan Plateau.

    Science.gov (United States)

    Guo, Junming; Kang, Shichang; Huang, Jie; Sillanpää, Mika; Niu, Hewen; Sun, Xuejun; He, Yuanqing; Wang, Shijing; Tripathee, Lekhendra

    2017-02-01

    In order to investigate the compositions and wet deposition fluxes of trace elements and rare earth elements (REEs) in the precipitation of the southeastern edge of the Tibetan Plateau, 38 precipitation samples were collected from March to August in 2012 in an urban site of Lijiang city in the Mt. Yulong region. The concentrations of most trace elements and REEs were higher during the non-monsoon season than during the monsoon season, indicating that the lower concentrations of trace elements and REEs observed during monsoon had been influenced by the dilution effect of increased precipitation. The concentrations of trace elements in the precipitation of Lijiang city were slightly higher than those observed in remote sites of the Tibetan Plateau but much lower than those observed in the metropolises of China, indicating that the atmospheric environment of Lijiang city was less influenced by anthropogenic emissions, and, as a consequence, the air quality was still relatively good. However, the results of enrichment factor and principal component analysis revealed that some anthropogenic activities (e.g., the increasing traffic emissions from the rapid development of tourism) were most likely important contributors to trace elements, while the regional/local crustal sources rather than anthropogenic activities were the predominant contributors to the REEs in the wet deposition of Lijiang city. Our study was relevant not only for assessing the current status of the atmospheric environment in the Mt. Yulong region, but also for specific management actions to be implemented for the control of atmospheric inputs and the health of the environment for the future. Copyright © 2016. Published by Elsevier B.V.

  18. Low temperature temporal and spatial atomic layer deposition of TiO{sub 2} films

    Energy Technology Data Exchange (ETDEWEB)

    Aghaee, Morteza, E-mail: m.aghaee@tue.nl; Maydannik, Philipp S. [ASTRaL Group, Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12, 50130 Mikkeli (Finland); Johansson, Petri; Kuusipalo, Jurkka [Paper Converting and Packaging Technology, Tampere University of Technology, P.O. Box 541, FI-33101 Tampere (Finland); Creatore, Mariadriana [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Homola, Tomáš; Cameron, David C. [R& D Center for Low-Cost Plasma and Nanotechnology Surface Modification, Masaryk University, Kotlářská 2, 611 37 Brno (Czech Republic)

    2015-07-15

    Titanium dioxide films were grown by atomic layer deposition (ALD) using titanium tetraisopropoxide as a titanium precursor and water, ozone, or oxygen plasma as coreactants. Low temperatures (80–120 °C) were used to grow moisture barrier TiO{sub 2} films on polyethylene naphthalate. The maximum growth per cycle for water, ozone, and oxygen plasma processes were 0.33, 0.12, and 0.56 Å/cycle, respectively. X-ray photoelectron spectrometry was used to evaluate the chemical composition of the layers and the origin of the carbon contamination was studied by deconvoluting carbon C1s peaks. In plasma-assisted ALD, the film properties were dependent on the energy dose supplied by the plasma. TiO{sub 2} films were also successfully deposited by using a spatial ALD (SALD) system based on the results from the temporal ALD. Similar properties were measured compared to the temporal ALD deposited TiO{sub 2}, but the deposition time could be reduced using SALD. The TiO{sub 2} films deposited by plasma-assisted ALD showed better moisture barrier properties than the layers deposited by thermal processes. Water vapor transmission rate values lower than 5 × 10{sup −4} g day{sup −1} m{sup −2} (38 °C and 90% RH) was measured for 20 nm of TiO{sub 2} film deposited by plasma-assisted ALD.

  19. Wet deposition and soil content of Beryllium - 7 in a micro-watershed of Minas Gerais (Brazil).

    Science.gov (United States)

    Esquivel L, Alexander D; Moreira, Rubens M; Monteiro, Roberto Pellacani G; Dos Santos, Anômora A Rochido; Juri Ayub, Jimena; Valladares, Diego L

    2017-04-01

    Beryllium-7 ( 7 Be) is a natural radionuclide of cosmogenic origin, normally used as a tracer for several environmental processes; such as soil redistribution, sediment source discrimination, atmospheric mass transport, and trace metal scavenging from the atmosphere. In this research the content of 7 Be in soil, its seasonal variation throughout the year and its relationship with the rainfall regime in the Mato Frio creek micro-watershed was investigated, to assess its potential use in estimating soil erosion. The 7 Be content in soil shows a marked variation throughout the year. Minimum 7 Be values were observed in the dry season (from April to September) and were between 7 and 14 times higher in the rainy season (from October to March). The seasonal oscillations in 7 Be soil content could be explained by the asymmetric rainfall regime. A highly linear relationship between rainfall amount and 7 Be deposition was observed in rain water. A good agreement between 7 Be soil content and 7 Be atmospheric deposition was noticed, mainly in wet months. 7 Be penetration in soil reaches a 5 cm depth, this could be explained by the soil type in the region. The soils are Acrisol type, characterized by low pH values and clay illuviation in deeper layers of the soil. In some regions of Brazil special attention should be paid if this radionuclide will be used as soil erosion tracer, taking into account the soil origin and its particular properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. The Characterization of Extreme Episodes of Wet and Dry Deposition of Pollutants on an Above Cloud-Base Forest during its Growing Season.

    Science.gov (United States)

    Defelice, T. P.; Saxena, V. K.

    1991-11-01

    An analysis of a 3-yr database (1986-88) acquired new Mount Mitchell (35°4405N, 82°1715W, 2038 m MSL) where the forest consists primarily of Fraser fir and some red spruce stands is presented. The site was immersed in clouds for 28%-41% of the time during each of the three growing seasons (15 May-15 September). This study only investigated extreme episodes of wet (cloud-water pH% .3:1)and dry (eg., an ozone concentration 70 ppb) acidic deposition. Extreme wet events occasionally relieved periods of high ozone ( 70 ppb) exposures during the final field intensive. Extreme wet and dry events could activate the decline mechanism in any above cloud-base forest, especially if the trees are exposed to such events during very early or very late stages of their Lives. The exposure of the forest to natural climatic stress, such as drought condition wintertime temperatures during the growing season, snow storm during early spring, etc., would also subject the forest to a stressful period during which the exposure to the aforementioned episodes of pollutant deposition might trigger a decline.On the average, one of three cloud events that traverse this site is extreme. These extreme events usually last about 4 h. form during periods of high atmospheric pressure, have a liquid water content of 0.10 g m3, and contain cloud droplets of mean diameter around 8.0 m. During the dissipating stages, such cloud events result in maximum acidic deposition. When such events are preceded by very high ozone ( 100 ppb), they may prove oven more detrimental to forest health. A precipitating cloud event (pH = 4.4 on the average) preceded by periods of very high ozone concentrations will become an extreme episode. Extreme acidic events can occur in association with 1) an 850-mb closed low, situated just north of Montreal, Canada, that advances southward into New York State, and 2) an 850-mb high extending over the Gulf of Mexico (between Florida and Louisiana) to over eastern Kansas. In

  1. Temporal variability of foliar nutrients: responses to nitrogen deposition and prescribed fire in a temperate steppe

    Science.gov (United States)

    Lü, Xiao-Tao; Reed, Sasha C.; Hou, Shuang-Li; Hu, Yan-Yu; Wei, Hai-Wei; Lü, Fu-Mei; Cui, Qiang; Han, Xing Guo

    2017-01-01

    Plant nutrient concentrations and stoichiometry drive fundamental ecosystem processes, with important implications for primary production, diversity, and ecosystem sustainability. While a range of evidence exists regarding how plant nutrients vary across spatial scales, our understanding of their temporal variation remains less well understood. Nevertheless, we know nutrients regulate plant function across time, and that important temporal controls could strongly interact with environmental change. Here, we report results from a 3-year assessment of inter-annual changes of foliar nitrogen (N) and phosphorus (P) concentrations and stoichiometry in three dominant grasses in response to N deposition and prescribed fire in a temperate steppe of northern China. Foliar N and P concentrations and their ratios varied greatly among years, with this temporal variation strongly related to inter-annual variation in precipitation. Nitrogen deposition significantly increased foliar N concentrations and N:P ratios in all species, while fire significantly altered foliar N and P concentrations but had no significant impacts on N:P ratios. Generally, N addition enhanced the temporal stability of foliar N and decreased that of foliar P and of N:P ratios. Our results indicate that plant nutrient status and response to environmental change are temporally dynamic and that there are differential effects on the interactions between environmental change drivers and timing for different nutrients. These responses have important implications for consideration of global change effects on plant community structure and function, management strategies, and the modeling of biogeochemical cycles under global change scenarios.

  2. Estimation of carbon sequestration in China’s forests induced by atmospheric wet nitrogen deposition using the principles of ecological stoichiometry

    Science.gov (United States)

    Zhu, Jianxing; He, Nianpeng; Zhang, Jiahui; Wang, Qiufeng; Zhao, Ning; Jia, Yanlong; Ge, Jianping; Yu, Guirui

    2017-11-01

    The worldwide development of industry and agriculture has generated noticeable increases in atmospheric nitrogen (N) deposition, significantly altering the global N cycle. These changes might affect the global carbon (C) cycle by enhancing forest C sequestration. Here, we used a series of datasets from eight typical forests along the north–south transect of eastern China (NSTEC). These datasets contained information on community structure, C and N concentrations in the soil and the organs (leaf, branch, stem, and fine-root) of 877 plant species, and atmospheric wet N deposition. Using the biomass weighting method, we scaled up the C:N ratios from the organ level to the ecosystem level, and evaluated the C sequestration rate (CSRN) in response to wet N deposition and N use efficiency (NUE) in China’s forests based on the principles of ecological stoichiometry. Our results showed that atmospheric wet N deposition had a modest impact on forest C storage. Specifically, mean CSRN was estimated as 231 kg C ha‑1 yr‑1 (range: 32.7–507.1 kg C ha‑1 yr‑1), accounting for 2.1% of NPP and 4.6% of NEP at the ecosystem level. The NUEeco of atmospheric N deposition ranged from 9.6‑27.7 kg C kg‑1 N, and increased with increasing latitude from subtropical to cold-temperate forests in China (P forest C sequestration based on the principles of ecological stoichiometry.

  3. Temporal variability of marine debris deposition at Tern Island in the Northwestern Hawaiian Islands.

    Science.gov (United States)

    Agustin, Alyssa E; Merrifield, Mark A; Potemra, James T; Morishige, Carey

    2015-12-15

    A twenty-two year record of marine debris collected on Tern Island is used to characterize the temporal variability of debris deposition at a coral atoll in the Northwestern Hawaiian Islands. Debris deposition tends to be episodic, without a significant relationship to local forcing processes associated with winds, sea level, waves, and proximity to the Subtropical Convergence Zone. The General NOAA Operational Modeling Environment is used to estimate likely debris pathways for Tern Island. The majority of modeled arrivals come from the northeast following prevailing trade winds and surface currents, with trajectories indicating the importance of the convergence zone, or garbage patch, in the North Pacific High region. Although debris deposition does not generally exhibit a significant seasonal cycle, some debris types contain considerable 3 cycle/yr variability that is coherent with wind and surface pressure over a broad region north of Tern. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. WRF/Chem study of dry and wet deposition of trifluoroacetic acid produced from the atmospheric degradation of a few short-lived HFCs

    Science.gov (United States)

    Kazil, J.; McKeen, S. A.; Kim, S.; Ahmadov, R.; Grell, G. A.; Talukdar, R. K.; Ravishankara, A. R.

    2011-12-01

    HFC-134a (1,1,1,2-tetrafluoroethane) is the prevalent (used in >80% passenger cars and commercial vehicles worldwide) refrigerant in automobile air conditioning units (MACs). With an atmospheric lifetime of ~14 years and a global warming potential (GWP) of 1430 on a 100-year time horizon, HFC-134a does not meet current and expected requirements for MAC refrigerants in many parts of the world. Therefore, substitutes with lower GWP are being sought. One of the simplest way to achieve lower GWP is to use chemicals with shorter atmospheric lifetimes. In this work, we investigate the dry and wet deposition and the rainwater concentration of trifluoroacetic acid (TFA) produced by the atmospheric oxidation of 2,3,3,3-tetrafluoropropene (TFP) and 1,2,3,3,3-pentafluoropropene (PFP). The WRF/Chem model was used to calculate dry and wet TFA deposition over the contiguous USA during the May-September 2006 period that would result from replacing HFC-134a in MACs with a 1:1 molar ratio mixture of 2,3,3,3-tetrafluoropropene (TFP) and 1,2,3,3,3-pentafluoropropene (PFP). The simulation is evaluated by comparing observations of precipitation and sulfate wet deposition at stations of the National Atmospheric Deposition Program (NADP). Simulated precipitation and sulfate wet deposition correlate well with the observations, but exhibit a positive bias for precipitation and a negative bias for sulfate wet deposition. Atmospheric lifetimes of TFP and PFP against oxidation by the hydroxyl radical OH, a prognostic species in WRF/Chem, are ~5 and ~4 days in the simulation, respectively. The model setup allows the attribution of dry and wet TFA deposition to individual source regions (California, Houston, Chicago, and the remaining contiguous USA in this work). TFA deposition is highest in the eastern USA because of numerous large sources and high precipitation in the region. West of the Continental Divide, TFA deposition is significantly lower, and its origin is dominated by emissions from

  5. Wet Deposition of Trace Metals at a Typical Urban Site in Southwestern China: Fluxes, Sources and Contributions to Aquatic Environments

    Directory of Open Access Journals (Sweden)

    Liuyi Zhang

    2017-12-01

    Full Text Available In this study, we quantified the atmospheric wet deposition (AWD of 13 trace metals (TMs and estimated their potential effects on the surface water of the Three Gorges Reservoir in China. Precipitation was collected in Wanzhou in southwestern China from March 2015 to February 2016. The concentrations and fluxes of the 13 TMs were in the ranges of 0.16–9.44 µg L−1 and 0.18–10.22 mg m−2 yr−1, respectively, in the order Al > Zn > Fe > Ba > Pb > Mn > Ti > Cd > Cu > As > V > Ni ≈ Cr. Using principal component analysis, it was found that Al, Ba, Cu, Fe, Mn and Zn were mainly derived from a mixture of soil and road dust, As, Cd, Cr, Pb and Ti primarily originated from the local industries, and Ni and V were related to diesel and gasoline combustion, including both vehicle exhaust emissions and ship emissions from the nearby Yangtze River. The estimated TM inputs to the Three Gorges Reservoir were 11.1, 11.0, 5.7, 5.3, 4.5, 2.7, 2.5, 1.5, 1.0, 0.7, 0.5, 0.2, and 0.2 t yr−1 for Al, Zn, Fe, Ba, Pb, Mn, Ti, Cd, Cu, As, V, Ni and Cr, respectively. The AWD TM fluxes in Wanzhou were lower than those in metropolises and their inputs were limited for surface water of the Three Gorges Reservoir. However, Cd was strongly enriched in precipitation and rainstorms greatly increased the surface water concentrations of Cd and Pb. Therefore, the behavior of Cd and Pb in southwestern mountain areas of China, including emission, transport, transformation, and their ecological effects, should be given more attention in future studies.

  6. Spatial and temporal estimation of soil loss for the sustainable management of a wet semi-arid watershed cluster.

    Science.gov (United States)

    Rejani, R; Rao, K V; Osman, M; Srinivasa Rao, Ch; Reddy, K Sammi; Chary, G R; Pushpanjali; Samuel, Josily

    2016-03-01

    The ungauged wet semi-arid watershed cluster, Seethagondi, lies in the Adilabad district of Telangana in India and is prone to severe erosion and water scarcity. The runoff and soil loss data at watershed, catchment, and field level are necessary for planning soil and water conservation interventions. In this study, an attempt was made to develop a spatial soil loss estimation model for Seethagondi cluster using RUSLE coupled with ARCGIS and was used to estimate the soil loss spatially and temporally. The daily rainfall data of Aphrodite for the period from 1951 to 2007 was used, and the annual rainfall varied from 508 to 1351 mm with a mean annual rainfall of 950 mm and a mean erosivity of 6789 MJ mm ha(-1) h(-1) year(-1). Considerable variation in land use land cover especially in crop land and fallow land was observed during normal and drought years, and corresponding variation in the erosivity, C factor, and soil loss was also noted. The mean value of C factor derived from NDVI for crop land was 0.42 and 0.22 in normal year and drought years, respectively. The topography is undulating and major portion of the cluster has slope less than 10°, and 85.3% of the cluster has soil loss below 20 t ha(-1) year(-1). The soil loss from crop land varied from 2.9 to 3.6 t ha(-1) year(-1) in low rainfall years to 31.8 to 34.7 t ha(-1) year(-1) in high rainfall years with a mean annual soil loss of 12.2 t ha(-1) year(-1). The soil loss from crop land was higher in the month of August with an annual soil loss of 13.1 and 2.9 t ha(-1) year(-1) in normal and drought year, respectively. Based on the soil loss in a normal year, the interventions recommended for 85.3% of area of the watershed includes agronomic measures such as contour cultivation, graded bunds, strip cropping, mixed cropping, crop rotations, mulching, summer plowing, vegetative bunds, agri-horticultural system, and management practices such as broad bed furrow, raised sunken beds, and harvesting available water

  7. Spatio-temporal trends of nitrogen deposition and climate effects on Sphagnum productivity in European peatlands.

    Science.gov (United States)

    Granath, Gustaf; Limpens, Juul; Posch, Maximilian; Mücher, Sander; de Vries, Wim

    2014-04-01

    To quantify potential nitrogen (N) deposition impacts on peatland carbon (C) uptake, we explored temporal and spatial trends in N deposition and climate impacts on the production of the key peat forming functional group (Sphagnum mosses) across European peatlands for the period 1900-2050. Using a modelling approach we estimated that between 1900 and 1950 N deposition impacts remained limited irrespective of geographical position. Between 1950 and 2000 N deposition depressed production between 0 and 25% relative to 1900, particularly in temperate regions. Future scenarios indicate this trend will continue and become more pronounced with climate warming. At the European scale, the consequences for Sphagnum net C-uptake remained small relative to 1900 due to the low peatland cover in high-N areas. The predicted impacts of likely changes in N deposition on Sphagnum productivity appeared to be less than those of climate. Nevertheless, current critical loads for peatlands are likely to hold under a future climate. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: Average Atmospheric (Wet) Deposition of Inorganic Nitrogen, 2002

    Science.gov (United States)

    Wieczorek, Michael; LaMotte, Andrew E.

    2010-01-01

    This tabular data set represents the average atmospheric (wet) deposition, in kilograms per square kilometer, of inorganic nitrogen for the year 2002 compiled for every catchment for MRB_E2RF1 of Major River Basins (MRBs, Crawford and others, 2006). The source data set for wet deposition was from the USGS's raster data set atmospheric (wet) deposition of inorganic nitrogen for 2002 (Gronberg, 2005). The MRB_E2RF1 catchments are based on a modified version of the U.S. Environmental Protection Agency's (USEPA) ERF1_2 and include enhancements to support national and regional-scale surface-water quality modeling (Nolan and others, 2002; Brakebill and others, 2011). Data were compiled for every catchment of MRB_E2RF1 catchments for the conterminous United States covering New England and Mid-Atlantic (MRB1), South Atlantic-Gulf and Tennessee (MRB2), the Great Lakes, Ohio, Upper Mississippi, and Souris-Red-Rainy (MRB3), the Missouri (MRB4), the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf (MRB5), the Rio Grande, Colorado, and the Great basin (MRB6), the Pacific Northwest (MRB7) river basins, and California (MRB8).

  9. Spatio-temporal evolution characteristics and prediction of dry-wet abrupt alternation during the summer monsoon in the middle and lower reaches of the Yangtze River Basin

    Science.gov (United States)

    Shan, Lijie; Zhang, Liping; Xiong, Zhe; Chen, Xinchi; Chen, Shaodan; Yang, Wei

    2017-05-01

    Summer rainfall anomalies have often posed a major water concern in China, and the variations and prediction of dry-wet abrupt alternation (DWAA) events have been receiving increasing attention from researchers. Based on precipitation and atmospheric circulation indices in the middle and lower reaches of the Yangtze River Basin, the spatio-temporal evolution characteristics and predictability of DWAA events were analyzed by calculating the dry-wet abrupt alternation index and selecting early warning signals. The results indicate that most long-cycle and short-cycle DWAA events, except in the period of May-June, are wet-to-dry (WTD) events and that the frequencies and intensities of WTD events have gradually decreased over time. The spatial distribution characteristics on the south shore of the Yangtze River are opposite to those on the north shore. Occurrences of DWAA events can be predicted to some extent by comparing the actual and critical values of select early warning signals. The results also indicate that the BP neural network model exhibits strong performance in simulating the occurrences of DWAA events and therefore may provide a useful reference for intraseasonal wet and dry management in the Yangtze River Basin.

  10. Spatial and Temporal Characteristics of Insulator Contaminations Revealed by Daily Observations of Equivalent Salt Deposit Density

    Directory of Open Access Journals (Sweden)

    Ling Ruan

    2015-01-01

    Full Text Available The accurate estimation of deposits adhering on insulators is of great significance to prevent pollution flashovers which cause huge costs worldwide. Researchers have developed sensors using different technologies to monitor insulator contamination on a fine time scale. However, there is lack of analysis of these data to reveal spatial and temporal characteristics of insulator contamination, and as a result the scheduling of periodical maintenance of power facilities is highly dependent on personal experience. Owing to the deployment of novel sensors, daily Equivalent Salt Deposit Density (ESDD observations of over two years were collected and analyzed for the first time. Results from 16 sites distributed in four regions of Hubei demonstrated that spatial heterogeneity can be seen at both the fine and coarse geographical scales, suggesting that current polluted area maps are necessary but are not sufficient conditions to guide the maintenance of power facilities. Both the local emission and the regional air pollution condition exert evident influences on deposit accumulation. A relationship between ESDD and PM10 was revealed by using regression analysis, proving that air pollution exerts influence on pollution accumulations on insulators. Moreover, the seasonality of ESDD was discovered for the first time by means of time series analysis, which could help engineers select appropriate times to clean the contamination. Besides, the trend component shows that the ESDD increases in a negative exponential fashion with the accumulation date (ESDD = a − b × exp(−time at a long time scale in real environments.

  11. Spatial and temporal characteristics of insulator contaminations revealed by daily observations of equivalent salt deposit density.

    Science.gov (United States)

    Ruan, Ling; Han, Ge; Zhu, Zhongmin; Zhang, Miao; Gong, Wei

    2015-01-29

    The accurate estimation of deposits adhering on insulators is of great significance to prevent pollution flashovers which cause huge costs worldwide. Researchers have developed sensors using different technologies to monitor insulator contamination on a fine time scale. However, there is lack of analysis of these data to reveal spatial and temporal characteristics of insulator contamination, and as a result the scheduling of periodical maintenance of power facilities is highly dependent on personal experience. Owing to the deployment of novel sensors, daily Equivalent Salt Deposit Density (ESDD) observations of over two years were collected and analyzed for the first time. Results from 16 sites distributed in four regions of Hubei demonstrated that spatial heterogeneity can be seen at both the fine and coarse geographical scales, suggesting that current polluted area maps are necessary but are not sufficient conditions to guide the maintenance of power facilities. Both the local emission and the regional air pollution condition exert evident influences on deposit accumulation. A relationship between ESDD and PM10 was revealed by using regression analysis, proving that air pollution exerts influence on pollution accumulations on insulators. Moreover, the seasonality of ESDD was discovered for the first time by means of time series analysis, which could help engineers select appropriate times to clean the contamination. Besides, the trend component shows that the ESDD increases in a negative exponential fashion with the accumulation date (ESDD = a - b × exp(-time)) at a long time scale in real environments.

  12. Eggshells are shaped by a precise spatio-temporal arrangement of sequentially deposited macromolecules.

    Science.gov (United States)

    Fernandez, M S; Araya, M; Arias, J L

    1997-04-01

    The avian eggshell is a composite bioceramic which is formed by a controlled interaction of an organic and an inorganic phase. The organic phase contains, among other constituents, type X collagen and proteoglycans, mainly keratan and dermatan sulfate. Understanding the principles governing the synthesis and temporo-spatial distribution of such macromolecules, and their influence on the organization of the crystalline phase, is an essential aspect of establishing the biological basis of the quality of eggshell, both as an embryonic chamber and as a natural food package. In the present study, we have examined the process of eggshell formation by immunohistochemistry, scanning electron microscopy and energy dispersive X-ray microanalysis. Precise sites and timing of secretion were established for the deposition of particular macromolecules. Type X collagen is detected at the very first moment of shell membrane formation. The appearance of keratan sulfate coincides with the appearance of mammillae, while dermatan sulfate is deposited later, coincident with shell matrix deposition. We propose that keratan sulfate, due to its precise localization, temporal appearance and calcium-binding affinity, relates to the maintenance of calcium reserve bodies, the primary source of calcium for the embryo. On the other hand, dermatan sulfate may control crystal growth, resulting in a preferential orientation of calcite crystals within the palisade layer.

  13. Spatial and temporal distribution of ore deposits, in relation with thermal anomalies

    Science.gov (United States)

    Harcouet, V.; Bonneville, A.; Guillou-Frottier, L.

    2003-04-01

    Ore deposits have formed over billion years of Earth's history with a discontinuous distribution in time and space.In time, their formation is episodical, and the data concerning the main deposit types show an alternation of periods with mineralisation followed by time gaps, with no large amount of ore generation. The "Snowball Earth" theory suggests that Banded Iron formations (BIF) are in relation with periods of intense global glaciations of Paleoproterozoic (2500-1600 Ma) and Neoproterozoic (1000-540 Ma) ages. During global glaciations, surface temperatures were of the order of -50°C and an ice layer of about 1km covered almost the entire Earth. We have performed analytical and numerical modelling of such events that shows the development of high thermal anomalies in the crust. These anomalies can reach several tens of degrees for a time lapse that depends on the duration of the glaciation. If the thermal impact is clear, the mechanical impact of the glaciations on the crustal rocks still needs to be evaluated to precisely assess the role of glaciations as a possible cause to some of the gaps in the temporal distribution of ore deposits.Ore deposits have also a heterogeneous spatial distribution: they are located in specific places of the Earth's crust, where thermo-mechanical and hydrothermal conditions have triggered their formation. The temperature pattern corresponding to these cases can prove to be particularly favourable to ore deposits. A good example of such deposits, is the Ashanti belt in Ghana of which we present a detailed study. It is the key district of gold mineralisation in the Paleoproterozoic terrane of West Africa. This is the second giant concentration of gold deposits after South Africa with a potential of about 2500 tons of gold. The Eburnean orogeny operated between 2.13 and 1.98 Ga. Two tectonic phases affected the area, a period of thrusting and a second one corresponding to transcurrent tectonism. A numerical modelling was performed

  14. 7Be and 210Pb wet/dry deposition in Melbourne, Australia and the development of deployable units for radiological emergency monitoring.

    Science.gov (United States)

    Courtier, Jane; Sdraulig, Sandra; Hirth, Gillian

    2017-11-01

    A large stainless-steel collection tray (with a surface area of one square metre) was purpose built and mounted on the roof of the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) building at Yallambie, Victoria, Australia. Using this system two years' worth of wet/dry deposition samples have been collected and analysed. Smaller portable units were also developed for deployment in an emergency and/or for environmental monitoring. The cosmogenic radionuclide 7Be and the naturally occurring terrestrial radionuclide 210Pb have been used to validate the systems. The data from the smaller units was successfully compared to the larger permanent collection unit for validation, thus finding the portable units fit for purpose. Monitoring of wet and dry fallout deposition is an important response to radiological emergencies. It can provide useful information in verifying predictive models of radionuclide atmospheric transport and dispersion, in addition to providing local deposition data. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  15. Temporal and spatial trends studied by lichen analysis: atmospheric deposition of trace elements in Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Aspiazu, J.; Cervantes, L.; Ramirez, J.; Lopez, J.; Villasenor, P. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Ramos, R.; Munoz, R. [Secretaria del Medio Ambiente, Gestion Ambiental del Aire, Mexico City (Mexico)

    2007-07-01

    Ball moss on Tillandsia recurvata (Bromeliaceae), collected in an area previously identified as unpolluted, was transplanted to thirteen bio-monitoring sites in the downtown and metropolitan areas of Mexico City (which cover a surface of 9,560 km{sup 2}) during the periods August 2002 - January 2003 and July 2003 - October 2003. A total of 52 lichens (weighing 300 g) were transplanted to each place. Two were analysed as zero or reference, El Chico National Park, a location 100 Km upwind from the city and the remaining 26 were hung in nylon net bags in order to be able to collect two transplanted tree month, out of every season over a one-year period. The concentrations were measured by the quantitative PIXE method based on an extemal beam facility. The atmospheric deposition for trace elements was inferred by its concentration in lichen samples collected in 2002 from 13 sites in Mexico and compared with data from a similar survey in 2003. The concentration of Cr, Cu, Co, Fe, Mn, Ni, Pb and Zn and other elements was determined for each sample. Maps for each element were drawn after a geostatistical estimate of the metal concentration in the sample was made. Maps were drawn for all elements with the estimated values. Geographical distribution patterns were obtained for the different metals, reflecting the contribution of natural and anthropogenic emission sources. The deposition patterns of V, As, Se, Cd and Pb are substantially influenced by long-range transport from other parts of Mexico City. For Cr, Fe, Co, Ni, and Cu, the deposition patterns are largely determined by contribution from point sources within Mexico and in the metropolitan area. The lichen data for Br and, in part, Se reflect an airborne supply from the environment. Contributions to trace element concentrations in lichen sources other than atmospheric deposition are identified and discussed. The Spatial and temporal variations in the distribution of metal concentration are discussed. (Author)

  16. Predicted spatio-temporal dynamics of radiocesium deposited onto forests following the Fukushima nuclear accident.

    Science.gov (United States)

    Hashimoto, Shoji; Matsuura, Toshiya; Nanko, Kazuki; Linkov, Igor; Shaw, George; Kaneko, Shinji

    2013-01-01

    The majority of the area contaminated by the Fukushima Dai-ichi nuclear power plant accident is covered by forest. To facilitate effective countermeasure strategies to mitigate forest contamination, we simulated the spatio-temporal dynamics of radiocesium deposited into Japanese forest ecosystems in 2011 using a model that was developed after the Chernobyl accident in 1986. The simulation revealed that the radiocesium inventories in tree and soil surface organic layer components drop rapidly during the first two years after the fallout. Over a period of one to two years, the radiocesium is predicted to move from the tree and surface organic soil to the mineral soil, which eventually becomes the largest radiocesium reservoir within forest ecosystems. Although the uncertainty of our simulations should be considered, the results provide a basis for understanding and anticipating the future dynamics of radiocesium in Japanese forests following the Fukushima accident.

  17. Uniformly wetting deposition of Co atoms on MoS(2) monolayer: a promising two-dimensional robust half-metallic ferromagnet.

    Science.gov (United States)

    Chen, Qian; Ouyang, Yixin; Yuan, Shijun; Li, Runze; Wang, Jinlan

    2014-10-08

    Synthesis of two-dimensional (2D) metal chalcogenide based half-metallic nanosheets is in high demand for modern electronics and spintronics applications. Herein, we predict from first-principles calculations that the 2D heterostructure Co/MoS2, consisting of a monolayer of Co atoms deposited on a single MoS2 sheet, possesses robust ferromagnetic and half-metallic features and exhibits 100% spin-filter efficiency within a broad bias range. Its ferromagnetic and half-metallic nature persists even when overlaid with a graphene sheet. Because of the relatively strong surface binding energy and low clustering ratio of Co atoms on the MoS2 surface, we predict that the heterostructure is synthesizable via wetting deposition of Co on MoS2 by electron-beam evaporation technique. Our work strongly suggests Co/MoS2 as a compelling and feasible candidate for highly effective information and high-density memory devices.

  18. Variations in the concentration and isotopic composition of nitrate nitrogen in wet deposition and their relation with meteorological conditions in Xi'an city, Northwest China

    Science.gov (United States)

    Xing, M.; Liu, W.

    2012-12-01

    The characterization of N isotopes in NO3- is an effective method to determine NO3- sources and NOX transformation mechanisms. Xi'an city is located in a semi-arid to arid region and is representative of most cities in the north and Northwest of China. Few studies have been carried out on N isotopes in wet deposition of this region. In this study, 29 wet deposition samples were collected from Xi'an city in northwestern China between March 2008 and May 2009 and analyzed for their volume-weighted NO3- and NH4+ concentrations and N isotopic compositions. Volume-weighted mean concentrations were 3.9 μmol L-1 for NO3- and 13.5 μmol L-1 for NH4+. The wet deposition samples showed pronounced seasonal variation in the N isotopic composition of NO3- with δ15N-NO3- ranging from -2.0‰ to +9.2‰ over the course of a year, with a mean value of +2.6 ± 2.6‰. Higher δ15N-NO3- values were observed in the cool season (November-May, +3.8‰) than in the warm season (June-October, +1.0‰). In autumn and winter in particular, the mean δ15N-NO3- values were clearly different (+0.9‰ and +6.7‰, respectively). Various factors are shown to lead to variation in the δ15N-NO3- values in wet deposition. One effect is changing ratios of N derived from agricultural/soil sources (low δ15N-NO3-, dominant in the warm season) and fossil fuel-derived NOX (high δ15N-NO3-, relatively more important in the cool season). However, in the cool season δ15N-NO3- unexpectedly shows a strong negative correlation with SO2 concentration, which should correlate with fossil fuel combustion inputs. This may be explained by interactions of N-species with other atmospheric pollutants. The results also suggest that temperature may be a significant factor affecting δ15N-NO3-. The NOX reacts in different ways depending on temperature, leading to a correlation of δ15N-NO3- with temperature. Moreover, the effects of dilution cannot be neglected here, as there is clear seasonal variation in

  19. Geochemistry and geochronology of carbonate-hosted base metal deposits in the southern Brooks Range, Alaska: temporal association with VMS deposits and metallogenic implications

    Science.gov (United States)

    Kelly, Karen; Slack, John; Selby, David

    2009-01-01

    The Brooks Range contains enormous accumulations of zinc and copper, either as VMS or sediment-hosted deposits. The Ruby Creek and Omar deposits are Cu-Co stratabound deposits associated with dolomitic breccias. Numerous volcanogenic Cu-Zn (+/-Ag, Au) deposits are situated ~20 km north of the Ruby Creek deposit. The carbonate-hosted deposits consist of chalcopyrite and bornite that fill open spaces, replace the matrix of the breccias, and occur in later cross-cutting veins. Cobaltiferous pyrite, chalcocite, minor tennantite-tetrahedrite, galena, and sphalerite are also present. At Ruby Creek, phases such as carrollite, renierite, and germanite occur rarely. The deposits have undergone post-depositional metamorphism (Ruby Creek, low greenschist facies; Omar, blueschist facies). The unusual geochemical signature includes Cu-Co +/- Ag, As, Au, Bi, Ge, Hg, Sb, and U with sporadic high Re concentrations (up to 2.7 ppm). New Re-Os data were obtained for chalcopyrite, bornite, and pyrite from the Ruby Creek deposit (analyses of sulfides from Omar are in progress). The data show extremely high Re abundances (hundreds of ppb, low ppm) and contain essentially no common Os. The Re-Os data provide the first absolute ages of ore formation for the Ruby Creek deposit and demonstrate that the Re-Os systematics of pyrite, chalcopyrite, and bornite are unaffected by greenschist metamorphism. The Re-Os data show that the main phase of Cu mineralization occurred at 384 +/-4.2 Ma, which coincides with zircon U-Pb ages from igneous rocks that are spatially and genetically associated with VMS deposits. This suggests a temporal link between regional magmatism and hydrothermal mineralization.

  20. Modeling dry and wet deposition of sulfate, nitrate, and ammonium ions in Jiuzhaigou National Nature Reserve, China using a source-oriented CMAQ model: Part II. Emission sector and source region contributions.

    Science.gov (United States)

    Qiao, Xue; Tang, Ya; Kota, Sri Harsha; Li, Jingyi; Wu, Li; Hu, Jianlin; Zhang, Hongliang; Ying, Qi

    2015-11-01

    A source-oriented Community Multiscale Air Quality (CMAQ) model driven by the meteorological fields generated by the Weather Research and Forecasting (WRF) model was used to study the dry and wet deposition of nitrate (NO3(-)), sulfate (SO4(2-)), and ammonium (NH4(+)) ions in the Jiuzhaigou National Nature Reserve (JNNR), China from June to August 2010 and to identify the contributions of different emission sectors and source regions that were responsible for the deposition fluxes. Contributions from power plants, industry, transportation, domestic, biogenic, windblown dust, open burning, fertilizer, and manure management sources to deposition fluxes in JNNR watershed and four EANET sites are determined. In JNNR, 96%, 82%, and 87% of the SO4(2-), NO3(-) and NH4(+) deposition fluxes are in the form of wet deposition of the corresponding aerosol species. Industry and power plants are the two major sources of SO4(2-) deposition flux, accounting for 86% of the total wet deposition of SO4(2-), and industry has a higher contribution (56%) than that of power plants (30%). Power plants and industry are also the top sources that are responsible for NO3(-) wet deposition, and contributions from power plants (30%) are generally higher than those from industries (21%). The major sources of NH4(+) wet deposition flux in JNNR are fertilizer (48%) and manure management (39%). Source-region apportionment confirms that SO2 and NOx emissions from local and two nearest counties do not have a significant impact on predicted wet deposition fluxes in JNNR, with contributions less than 10%. While local NH3 emissions account for a higher fraction of the NH4(+) deposition, approximately 70% of NH4(+) wet deposition in JNNR originated from other source regions. This study demonstrates that S and N deposition in JNNR is mostly from long-range transport rather than from local emissions, and to protect JNNR, regional emission reduction controls are needed. Copyright © 2015 Elsevier B.V. All

  1. Mechanisms and rates of atmospheric deposition of selected trace elements and sulfate to a deciduous forest watershed. [Roles of dry and wet deposition concentrations measured in Walker Branch Watershed

    Energy Technology Data Exchange (ETDEWEB)

    Lindberg, S.E.; Harriss, R.C.; Turner, R.R.; Shriner, D.S.; Huff, D.D.

    1979-06-01

    The critical links between anthropogenic emissions to the atmosphere and their effects on ecosystems are the mechanisms and rates of atmospheric deposition. The atmospheric input of several trace elements and sulfate to a deciduous forest canopy is quantified and the major mechanisms of deposition are determined. The study area was Walker Branch Watershed (WBW) in eastern Tennessee. The presence of a significant quantity of fly ash and dispersed soil particles on upward-facing leaf and flat surfaces suggested sedimentation to be a major mechanism of dry deposition to upper canopy elements. The agreement for deposition rates measured to inert, flat surfaces and to leaves was good for Cd, SO/sub 4//sup =/, Zn, and Mn but poor for Pb. The precipitation concentrations of H/sup +/, Pb, Mn, and SO/sub 4//sup =/ reached maximum values during the summer months. About 90% of the wet deposition of Pb and SO/sub 4//sup =/ was attributed to scavenging by in-cloud processes while for Cd and Mn, removal by in-cloud scavenging accounted for 60 to 70% of the deposition. The interception of incoming rain by the forest canopy resulted in a net increase in the concentrations of Cd, Mn, Pb, Zn, and SO/sub 4//sup =/ but a net decrease in the concentration of H/sup +/. The source of these elements in the forest canopy was primarily dry deposited aerosols for Pb, primarily internal plant leaching for Mn, Cd, and Zn, and an approximately equal combination of the two for SO/sub 4//sup =/. Significant fractions of the total annual elemental flux to the forest floor in a representative chestnut oak stand were attributable to external sources for Pb (99%), Zn (44%), Cd (42%), SO/sub 4//sup =/ (39%), and Mn (14%), the remainder being related to internal element cycling mechanisms. On an annual scale the dry deposition process constituted a significant fraction of the total atmospheric input. (ERB)

  2. Contributions of low molecular weight carboxylic acids to aerosols and wet deposition in a natural subtropical broad-leaved forest environment

    Science.gov (United States)

    Tsai, Ying I.; Kuo, Su-Ching

    2013-12-01

    The carboxylic acid component of autumn aerosol and wet deposition (fog water and rainwater) in a broad-leaved forest in central Taiwan was investigated. High levels of low molecular weight carboxylic acids (LMWCAs) were noted in all deposition types. Acetic acid, oxalic acid and formic acid were the most prevalent carboxylic acids, together accounting for 72.2% (fog water), 86.7% (rain water), 77.2% (PM2.5) and 88.3% (PM2.5-10) of total carboxylic acid. The forest fog water contained 2453.9 ± 1030.5 ng mL-1 of carboxylic acid, 2.71 times more than was contained in forest rainwater. In PM, most carboxylic acid existed in the fine PM2.5 aerosol (576.6 ± 254.1 ng m-3 or 6.28 times more than was contained in PM2.5-10. Most carboxylic acids in PM had higher concentrations during the day. Pyruvic acid concentration was higher during the night (2.97 times), however, owing to its rapid photodegradation during the day. Citric acid accounted for 9.1% of the total carboxylic acid in fog water compared with just 1.8% in rainwater, confirming its origin from emissions from leaves. Raman spectroscopy was used to observe the photochemical conversion of citric acid into intermediate products and this observation confirmed that the carboxylic acids identified in the forest dry and wet depositions originated directly from biological emissions in the forest environment.

  3. Seasonal Variations in Mercury Deposition over the Yellow Sea, July 2007 through April 2008

    Energy Technology Data Exchange (ETDEWEB)

    ghim, young sung; Oh, Hyun Sun; Kim, Jin Young; Woo, Jung-Hun; Chang, Young-Soo

    2016-09-01

    Spatial and temporal variations of mercury, including dry and wet deposition fluxes, were assessed over Northeast Asia, targeting the Yellow Sea, using meteorology and chemistry models. Four modeling periods, each representative of one of the four seasons, were selected. Modeling results captured general patterns and behaviors, and fell within similar ranges with respect to observations. However, temporal variations of mercury were not closely matched, possibly owing to the effects of localized emissions. Modeling results indicated that dry deposition is correlated with wind speed, while wet deposition is correlated with precipitation amount. Overall, the wet deposition flux of 66 ng/m2-day was about twice as large as the dry deposition flux of 32 ng/m2-day, when averaged over the four modeling periods. Dry deposition occurred predominantly in the form of reactive gaseous mercury (RGM). In contrast, RGM accounted for only about two-thirds of wet deposition, while particulate mercury accounted for the remainder.

  4. Spatial and temporal patterns in erosion and deposition in the York River, Chesapeake Bay, VA

    Science.gov (United States)

    Rodríguez-Calderón, Cielomar; Kuehl, Steven A.

    2013-01-01

    Seasonal patterns of seabed erosion and deposition in a dynamic estuarine environment, the York River (USA), are examined through acoustic studies and seabed sampling to identify the dominant environmental controls on sediment mobility. Areas near Clay Bank in the York River were surveyed monthly using a dual-frequency sonar for a 12 month period. In addition, six stations within these areas were sampled during the surveys. Strong spatial and temporal variations of a soft mud layer were identified, providing new insight to recurring seasonal and spatial patterns in deposition and erosion in the middle reaches of the York River estuary. Sub-bottom data indicated maximum thickness (5-22 cm ± 4 cm) of the soft mud layer during spring and winter from April 2008 through March 2009. Minimum thicknesses (1-12 cm ± 4 cm) of the soft mud layer were observed during summer and fall. Maximum thickness coincided with the occurrence of the secondary turbidity maximum near Clay Bank in the York River. Spatial variations in the soft-mud layer thickness were also identified between and within the York River secondary channel, the inactive oyster reef area, the south west flank of the main channel, and the main channel. The upriver secondary channel, the south west channel flank, and the main channel areas were physically dominated. The downriver secondary channel area was biologically dominated and the inactive oyster reef area reflected both physical and biological processes. Water content trends showed no correlation with seabed stability in this area. Observed changes in soft mud thicknesses are interpreted to result from both biological and physical factors, which vary markedly between winter/spring and summer/fall seasons, and among the different environments of the estuary's channel.

  5. Identification sources of pollen spectra in dry and wet atmospheric deposition in the forest-steppe zone of Altai Krai (Russia)

    Science.gov (United States)

    Ryabchinskaya, Natalia; Nenasheva, Galina; Malygina, Natalia

    2015-04-01

    Pollen spectra circulating in the atmosphere contain the important information about primary biological aerosol particles (PBAP), worldwide interest in which has significantly increased in recent decades [Despres, 2012]. It is related to the fact that many researchers suggest primary aerosols as a condensation nucleus significantly affected on the formation of clouds and precipitation and, consequently, on the hydrological cycle and climate, especially at the regional level [Andreae et al., 2008; Poschlet et al., 2010; Prenni et al., 2009]. We present the comparison of pollen spectra obtained during the dry and wet atmospheric deposition in Altai Krai (Russia) and identification of the sources/regions of their receipts. Altai Krai is located in the center of the Eurasian continent, at the border of several natural and climatic zones. A significant part of the region's territory is characterized as a forest-steppe zone with a lot of natural and anthropogenic landscapes, accompanied by continental climate. It provides a rich diversity of natural vegetation and cultural associations. During last 10 years pollen grains has been monitored in the airspace of Barnaul city (the capital of Altai Krai) located in the central part of the forest-steppe zone). During the monitoring, the attempts to determine the origin of pollen spectra (local or introduced) were made as well. In the long-term average dates of the first wave of dusting in the spring season 2014 Burkard pollen traps were used in order to monitor the airspace in Barnaul, namely dry deposition of pollen grains [Nenasheva, 2013]. To estimate the wet deposition PBAP (pollen), which can reach 80% in the middle latitudes, precipitation sampler were installed close to Burkard pollen traps in order to sample precipitation. The samples were filtered through a filter having a pore diameter of 1 µm, then prepared and examined for the presence of pollen grains. The comparison of the results of pollen analysis of 10 samples

  6. Integration of metal organic chemical vapour deposition and wet chemical techniques to obtain highly ordered porous ZnO nanoplatforms.

    Science.gov (United States)

    Fragalà, Maria Elena; Aleeva, Yana; Satriano, Cristina

    2011-09-01

    Large-area, highly ordered ZnO micropores-arrays consisting of ZnO nanotubes delimited by ZnO nanorods have been successfully fabricated and tested for protein sensing applications. ZnO seed layers have been deposited by Metal Organic Chemical Vapour Deposition and readily patterned by Colloidal Lithography to attain ZnO nanorods growth at selective sites by Chemical Bath Deposition. The used synthetic approach has been proven effective for the easy assembly of ZnO nanoplatforms into high-density arrays. Both patterned and unpatterned ZnO nanorods have been morphologically and compositionally characterised and, thus, tested for model studies of protein mobility at the interface. The patterned layers, having a higher contribution of surface polar moieties than the corresponding unpatterned surfaces, exhibit a reduced lateral diffusion of the adsorbed protein. This evidence is related to the intrinsic porous nature of the ZnO hemispherical arrays characterised by a nanotube-nanorod hybrid networks. The present study gives a great impetus to the fabrication of tunable ZnO nanoplatforms having multiple morphologies and exceptionally high surface areas suitable for application in sensing devices.

  7. Spatial and temporal dynamics of stream chemistry in a forested watershed impacted by atmospheric deposition

    Science.gov (United States)

    Piatek, K. B.; Christopher, S. F.; Mitchell, M. J.

    2008-09-01

    We analyzed spatial and temporal dynamics of solute chemistry in a forest watershed impacted by atmospheric deposition in the Adirondack Mountains of New York State, USA. Spatial dynamics of solute chemistry and natural abundance isotopes of nitrate (15N and 18O) were examined in 6 locations and the watershed outlet in 2001 and 2002. Temporal dynamics were examined during 5 discharge periods: winter, snowmelt, spring, summer, and fall, which were based on discharge levels at the outlet. Solute concentrations were statistically significantly different (p≤0.05) among stream sampling locations and discharge periods, with no interaction effects. Groundwater sources located in upper watershed controlled stream chemistry at higher elevations with highest pH, Ca2+, sum of base cations, Si, NO3-, total N, and SO42- and lowest Al concentrations. Two low elevation wetlands had a substantial influence over stream chemistry at those locations contributing lowest NO3-, total N, and highest DOC and DON. Snowmelt exhibited among the lowest pH, sum of base cations, and SO42-, and highest NO3-, total N, DON, and total Al; snowmelt appeared to dilute groundwater, and flush stored soil-derived solutes. Summer discharge, composed mainly of groundwater, exhibited the lowest flow, among the highest Mg2+, Ca2+, and lowest DON, DOC, and total Al concentrations. Isotopic analysis together with patterns of NH4+ versus NO3- dynamics indicated that NO3- was microbial, generated in fall and accumulated in winter in upper watershed soils, and flushed to stream during high discharge events. Highest discharge in snowmelt 2001, a summer drought in 2002, and fall storms following the drought were further evaluated for their specific effects on stream chemistry. Snowmelt 2001 had the lowest pH and highest NO3-, base flow during summer drought had the lowest total Al, and storms in fall 2002 had highest SO42- of all periods, but all other solute concentrations were comparable to other discharge

  8. Validation of dentine deposition rates in beluga whales by interspecies cross dating of temporal δ13C trends in teeth

    Directory of Open Access Journals (Sweden)

    Cory JD Matthews

    2014-11-01

    Full Text Available Isotopic time series from sequentially sampled growth layer groups (GLGs in marine mammal teeth can be combined to build chronologies allowing assessment of isotopic variation in marine ecosystems. Synchronous recording of baseline isotopic variation across dentinal GLGs of species with temporal and spatial overlap in foraging offers a unique opportunity for validation of marine mammal age estimation procedures through calibration of GLG deposition rates in one species against another whose GLG deposition has been independently determined. In this study, we compare trends in stable carbon isotope ratios (d13C across dentinal GLGs of three eastern Canadian Arctic (ECA beluga (Delphinapterus leucas populations through the 1960s-2000s with a d13C time series measured across dentinal GLGs of ECA/Northwest Atlantic killer whales (Orcinus orca from 1944-1999. We use confirmed annual GLG deposition in killer whales as a means to assess beluga GLG deposition, and show linear d13C declines across chronologies of both species were statistically indistinguishable when based on annual GLG deposition in beluga whales, but differed when based on biannual deposition. We suggest d13C declines reflect the oceanic 13C Suess effect, and provide additional support for annual GLG deposition in beluga whales by comparing rates of d13C declines across beluga GLGs with published annual d13C declines attributed to the oceanic 13C Suess effect in the North Atlantic.

  9. Spatial and temporal variability in sedimentation rates associated with cutoff channel infill deposits: Ain River, France

    Science.gov (United States)

    Piegay, H.; Hupp, C.R.; Citterio, A.; Dufour, S.; Moulin, B.; Walling, D.E.

    2008-01-01

    Floodplain development is associated with lateral accretion along stable channel geometry. Along shifting rivers, the floodplain sedimentation is more complex because of changes in channel position but also cutoff channel presence, which exhibit specific overflow patterns. In this contribution, the spatial and temporal variability of sedimentation rates in cutoff channel infill deposits is related to channel changes of a shifting gravel bed river (Ain River, France). The sedimentation rates estimated from dendrogeomorphic analysis are compared between and within 14 cutoff channel infills. Detailed analyses along a single channel infill are performed to assess changes in the sedimentation rates through time by analyzing activity profiles of the fallout radionuclides 137Cs and unsupported 210Pb. Sedimentation rates are also compared within the channel infills with rates in other plots located in the adjacent floodplain. Sedimentation rates range between 0.65 and 2.4 cm a -1 over a period of 10 to 40 years. The data provide additional information on the role of distance from the bank, overbank flow frequency, and channel geometry in controlling the sedimentation rate. Channel infills, lower than adjacent floodplains, exhibit higher sedimentation rates and convey overbank sediment farther away within the floodplain. Additionally, channel degradation, aggradation, and bank erosion, which reduce or increase the distance between the main channel and the cutoff channel aquatic zone, affect local overbank flow magnitude and frequency and therefore sedimentation rates, thereby creating a complex mosaic of sedimentation zones within the floodplain and along the cutoff channel infills. Last, the dendrogeomorphic and 137Cs approaches are cross validated for estimating the sedimentation rate within a channel infill. Copyright 2008 by the American Geophysical Union.

  10. Spatial and temporal distribution of the dust deposition in Central Asia - results from a long term monitoring program

    Science.gov (United States)

    Groll, M.; Opp, Chr.; Aslanov, I.

    2013-06-01

    The aeolian transport of dust is an important process in Central Asia. Anthropogenic desertification and the desiccation of the Aral Sea have increased the overall dust emission and transport from this region and the local dust storm frequency during the last decades. Reliable ground data, however, are collected only sporadically, so the knowledge about the spatial and temporal distribution and dynamics of the dust deposition in the Aral Sea basin is fragmented and inconsistent at best. A long-term monitoring program was installed and sustained by three research projects. The results included in this article cover the dust deposition between 2003 and 2010 from 21 stations in Uzbekistan, Kazakhstan, and Turkmenistan. They confirm that the aeolian dust transport occurs mainly in the Southern direction. The highest average monthly deposition rate was registered in Uzbekistan (56.2 g m-2), while the percentage of months with a very intense (and potentially harmful) dust deposition flux was highest in Turkmenistan (36.4%). A majority of samples were collected during months with a dust deposition of less than 10.0 g m-2, while only 6% of all samples showed high monthly deposition intensities of more than 100 g m-2. The Kyzyl Kum, Kara Kum, and Aral Kum were identified as the main sources for aeolian dust in the Aral Sea basin. The impact of the Aral Kum as the dominant source of aeolian dust is limited to a region of approximately 500,000 km2 surrounding the former Aral Sea. The Kara Kum is characterized by a very high frequency of dust storms of a local and regional magnitude, and close to the Kyzyl Kum, monthly dust deposition rates of up to 9,600 g m-2 were registered. An analysis of the temporal distribution of the dust deposition showed a slight increase in the dust deposition activity and intensity between 2003 and 2010, with a strong inter-annual and seasonal dynamic. The highest average dust deposition was registered in June, and a second phase of intense dust

  11. Influence of temporal changes in relative humidity on dry deposition velocities and fluxes of aerosol particles bearing trace elements

    Science.gov (United States)

    Quinn, T. L.; Ondov, J. M.

    To estimate the significance of temporal changes in RH on dry deposition to a water surface, size-segregated particulate aerosol samples were collected with nine-stage micro-orifice impactors at average RH ranging from mmad) were calculated from the resulting size spectra for each element and used to characterize particle growth as a function of RH. The spectra were used in an adaptation of the Williams (1982)' model along with half-hourly meteorological observations made over a nine-month period at a northern Bay Buoy station to investigate the effects of temporal variations in RH on the deposition fluxes of important elemental aerosol constituents. Additional modeling was done using the hygroscopic growth equation of Koutrakis et al. (1989) developed for atmospheric sulfate. At 60% RH, mmads for fine-particle components of As, Sb, Se, V, and Zn aerosols were: 0.29, 0.33, 0.30, 0.27, and 0.4 μm, i.e. comparable to those measured previously in College Park, MD Ondov and Divita, 1993. These increased from 50 to 300% at RH=95±4%. Modeling results suggest that temporal RH effects account for from 1.5- to>four-fold increase in the deposition of fine particle fractions which bear the bulk of many these elements.

  12. Constraints on post-depositional isotope modifications in East Antarctic firn from analysing temporal changes of isotope profiles

    Science.gov (United States)

    Münch, Thomas; Kipfstuhl, Sepp; Freitag, Johannes; Meyer, Hanno; Laepple, Thomas

    2017-09-01

    The isotopic composition of water in ice sheets is extensively used to infer past climate changes. In low-accumulation regions their interpretation is, however, challenged by poorly constrained effects that may influence the initial isotope signal during and after deposition of the snow. This is reflected in snow-pit isotope data from Kohnen Station, Antarctica, which exhibit a seasonal cycle but also strong interannual variations that contradict local temperature observations. These inconsistencies persist even after averaging many profiles and are thus not explained by local stratigraphic noise. Previous studies have suggested that post-depositional processes may significantly influence the isotopic composition of East Antarctic firn. Here, we investigate the importance of post-depositional processes within the open-porous firn (≳ 10 cm depth) at Kohnen Station by separating spatial from temporal variability. To this end, we analyse 22 isotope profiles obtained from two snow trenches and examine the temporal isotope modifications by comparing the new data with published trench data extracted 2 years earlier. The initial isotope profiles undergo changes over time due to downward advection, firn diffusion and densification in magnitudes consistent with independent estimates. Beyond that, we find further modifications of the original isotope record to be unlikely or small in magnitude (≪ 1 ‰ RMSD). These results show that the discrepancy between local temperatures and isotopes most likely originates from spatially coherent processes prior to or during deposition, such as precipitation intermittency or systematic isotope modifications acting on drifting or loose surface snow.

  13. Ammonia emissions in the United States, European Union, and China derived by high-resolution inversion of ammonium wet deposition data: Interpretation with a new agricultural emissions inventory (MASAGE_NH3)

    Science.gov (United States)

    We use the adjoint of a global 3-D chemical transport model (GEOS-Chem) to optimizeammonia (NH3European Union, and China by inversion of 2005–2008 network data for NH+4 wet deposition fluxes. Optimized emissions are derive...

  14. Influences of in-cloud aerosol scavenging parameterizations on aerosol concentrations and wet deposition in ECHAM5-HAM

    Directory of Open Access Journals (Sweden)

    B. Croft

    2010-02-01

    Full Text Available A diagnostic cloud nucleation scavenging scheme, which determines stratiform cloud scavenging ratios for both aerosol mass and number distributions, based on cloud droplet, and ice crystal number concentrations, is introduced into the ECHAM5-HAM global climate model. This scheme is coupled with a size-dependent in-cloud impaction scavenging parameterization for both cloud droplet-aerosol, and ice crystal-aerosol collisions. The aerosol mass scavenged in stratiform clouds is found to be primarily (>90% scavenged by cloud nucleation processes for all aerosol species, except for dust (50%. The aerosol number scavenged is primarily (>90% attributed to impaction. 99% of this impaction scavenging occurs in clouds with temperatures less than 273 K. Sensitivity studies are presented, which compare aerosol concentrations, burdens, and deposition for a variety of in-cloud scavenging approaches: prescribed fractions, a more computationally expensive prognostic aerosol cloud processing treatment, and the new diagnostic scheme, also with modified assumptions about in-cloud impaction and nucleation scavenging. Our results show that while uncertainties in the representation of in-cloud scavenging processes can lead to differences in the range of 20–30% for the predicted annual, global mean aerosol mass burdens, and near to 50% for accumulation mode aerosol number burden, the differences in predicted aerosol mass concentrations can be up to one order of magnitude, particularly for regions of the middle troposphere with temperatures below 273 K where mixed and ice phase clouds exist. Different parameterizations for impaction scavenging changed the predicted global, annual mean number removal attributed to ice clouds by seven-fold, and the global, annual dust mass removal attributed to impaction by two orders of magnitude. Closer agreement with observations of black carbon profiles from aircraft (increases near to one order of magnitude for mixed phase clouds

  15. Modeling wet deposition of inorganics over Northeast Asia with MRI-PM/c and the effects of super large sea salt droplets at near-the-coast stations

    Science.gov (United States)

    Kajino, M.; Deushi, M.; Maki, T.; Oshima, N.; Inomata, Y.; Sato, K.; Ohizumi, T.; Ueda, H.

    2012-06-01

    We conducted a regional-scale simulation (with grid spacing = 60 km) over Northeast Asia for the entire year of 2006 by using an aerosol chemical transport model, the lateral and upper boundary concentrations of which we predicted with a global stratospheric and tropospheric chemistry-climate model, with a horizontal resolution of T42 (grid spacing ~300 km) and a time resolution of 1 h. The present one-way nested global-through-regional-scale model is called the Meteorological Research Institute - Passive-tracers Model system for atmospheric Chemistry (MRI-PM/c). We evaluated the model performance with respect to the major inorganic components in rain and snow measured by stations of the Acid Deposition Monitoring Network in East Asia (EANET). Through statistical analysis, we show that the model successfully reproduced the regional-scale processes of emission, transport, transformation, and wet deposition of major inorganic species derived from anthropogenic and natural sources, including SO42-, NH4+, NO3-, Na+ and Ca2+. Interestingly, the only exception was Na+ in precipitation at near-coastal stations (where the distance from the coast was from 150 to 700 m), concentrations of which were significantly underestimated by the model, by up to a factor of 30. This result suggested that the contribution of short-lived, super-large sea salt droplets (SLSD; D > 10-100 μm) was substantial in precipitation samples at stations near the coast of Japan; thus samples were horizontally representative only within the traveling distances of SLSD (from 1 to 10 km). Nevertheless, the calculated effect of SLSD on precipitation pH was very low, a change of about +0.014 on average, even if the ratio of SLSD to all sea salt in precipitation was assumed to be 90%.

  16. Atmospheric bulk deposition of polycyclic aromatic hydrocarbons in Shanghai: Temporal and spatial variation, and global comparison.

    Science.gov (United States)

    Feng, Daolun; Liu, Ying; Gao, Yi; Zhou, Jinxing; Zheng, Lirong; Qiao, Gang; Ma, Liming; Lin, Zhifen; Grathwohl, Peter

    2017-11-01

    Atmospheric deposition leads to accumulation of atmospheric polycyclic aromatic hydrocarbons (PAHs) on urban surfaces and topsoils. To capture the inherent variability of atmospheric deposition of PAHs in Shanghai's urban agglomeration, 85 atmospheric bulk deposition samples and 7 surface soil samples were collected from seven sampling locations during 2012-2014. Total fluxes of 17 PAHs were 587-32,300 ng m -2 day -1 , with a geometric mean of 2600 ng m -2 day -1 . The deposition fluxes were categorized as moderate to high on a global scale. Phenanthrene, fluoranthene and pyrene were major contributors. The spatial distribution of deposition fluxes revealed the influence of urbanization/industrialization and the relevance of local emissions. Meteorological conditions and more heating demand in cold season lead to a significant increase of deposition rates. Atmospheric deposition is the principal pathway of PAHs input to topsoils and the annual deposition load in Shanghai amounts to ∼4.5 tons (0.7 kg km -2 ) with a range of 2.5-10 tons (0.4-1.6 kg km -2 ). Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Large-scale spatial variability of major ions in the atmospheric wet deposition along the China–Antarctica transect (31°N–69°S

    Directory of Open Access Journals (Sweden)

    G. Shi

    2012-07-01

    Full Text Available Twenty-two atmospheric wet deposition samples were collected along the large-scale transect from China to Antarctica, and the major ion components as well as their sources were analysed. It is the first time that chemical composition variation of precipitation has been investigated on such a large-scale transect. The results show that the precipitations exhibit near-neutral pH on the average. On the whole, ionic levels on an equivalent basis are presented as Cl−>Na+>Mg2+> >Ca2+>K+>S2−4>NA−3, and ionic contents of rainfall are generally higher compared with values of snowfall. Ionic concentrations vary greatly on the study transect, and the values of the Northern Hemisphere are relatively higher. Both enrichment factor and principal component analyses reveal that Cl−, Na+, K+ and Mg2+ are mainly related to sea salt, namely, the marine source. The good correlations between marine-sourced ions and wind speed indicate that seawater sprays are important sources of precipitation ions. Land-based sources, for example, human activities, are the primary sources of NO−3,NH+4 and Ca2+. SO2−4 partly originates from sea salt, but anthropogenic and biogenic sources are also important contributors. Backward trajectories illustrate well the different main sources and transport routes of the precipitation ions.

  18. Spatial and temporal patterns in trace element deposition to lakes in the Athabasca oil sands region (Alberta, Canada)

    Science.gov (United States)

    Cooke, Colin A.; Kirk, Jane L.; Muir, Derek C. G.; Wiklund, Johan A.; Wang, Xiaowa; Gleason, Amber; Evans, Marlene S.

    2017-12-01

    The mining and processing of the Athabasca oil sands (Alberta, Canada) has been occurring for decades; however, a lack of consistent regional monitoring has obscured the long-term environmental impact. Here, we present sediment core results to reconstruct spatial and temporal patterns in trace element deposition to lakes in the Athabasca oil sands region. Early mining operations (during the 1970s and 1980s) led to elevated V and Pb inputs to lakes located order control over lake sediment base cation concentrations and overall lake sediment geochemical composition. Trace element concentrations generally did not exceed Canadian sediment quality guidelines, and no spatial or temporal trends were observed in the frequency of guideline exceedence. Our results demonstrate that early mining efforts had an even greater impact on trace element cycling than has been appreciated previously, placing recent monitoring efforts in a critical long-term context.

  19. The role of spatial and temporal radiation deposition in inertial fusion chambers: the case of HiPER¿

    OpenAIRE

    Alvarez Ruiz, Jesus; Garoz Gómez, David; Gonzalez Arrabal, Raquel; Rivera de Mena, Antonio; Perlado Martín, José Manuel

    2011-01-01

    The first wall armour for the reactor chamber of HiPER will have to face short energy pulses of 5 to 20 MJ mostly in the form of x-rays and charged particles at a repetition rate of 5–10 Hz. Armour material and chamber dimensions have to be chosen to avoid/minimize damage to the chamber, ensuring the proper functioning of the facility during its planned lifetime. The maximum energy fluence that the armour can withstand without risk of failure, is determined by temporal and spatial deposition of...

  20. Constraints on post-depositional isotope modifications in East Antarctic firn from analysing temporal changes of isotope profiles

    Directory of Open Access Journals (Sweden)

    T. Münch

    2017-09-01

    Full Text Available The isotopic composition of water in ice sheets is extensively used to infer past climate changes. In low-accumulation regions their interpretation is, however, challenged by poorly constrained effects that may influence the initial isotope signal during and after deposition of the snow. This is reflected in snow-pit isotope data from Kohnen Station, Antarctica, which exhibit a seasonal cycle but also strong interannual variations that contradict local temperature observations. These inconsistencies persist even after averaging many profiles and are thus not explained by local stratigraphic noise. Previous studies have suggested that post-depositional processes may significantly influence the isotopic composition of East Antarctic firn. Here, we investigate the importance of post-depositional processes within the open-porous firn (≳ 10 cm depth at Kohnen Station by separating spatial from temporal variability. To this end, we analyse 22 isotope profiles obtained from two snow trenches and examine the temporal isotope modifications by comparing the new data with published trench data extracted 2 years earlier. The initial isotope profiles undergo changes over time due to downward advection, firn diffusion and densification in magnitudes consistent with independent estimates. Beyond that, we find further modifications of the original isotope record to be unlikely or small in magnitude (≪ 1 ‰ RMSD. These results show that the discrepancy between local temperatures and isotopes most likely originates from spatially coherent processes prior to or during deposition, such as precipitation intermittency or systematic isotope modifications acting on drifting or loose surface snow.

  1. Temporal changes in the distribution, methylation, and bioaccumulation of newly deposited mercury in an aquatic ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Orihel, Diane M. [Clayton H. Riddell Faculty of Environment, Earth, and Resources, University of Manitoba, Winnipeg, Manitoba, R3T 2N2 (Canada); Freshwater Institute, Fisheries and Oceans Canada, 501 University Crescent, Winnipeg, Manitoba, R3T 2N6 (Canada)], E-mail: orihel@ualberta.ca; Paterson, Michael J.; Blanchfield, Paul J.; Bodaly, R.A. [Freshwater Institute, Fisheries and Oceans Canada, 501 University Crescent, Winnipeg, Manitoba, R3T 2N6 (Canada); Gilmour, Cynthia C. [Smithsonian Environmental Research Center, 647 Contees Wharf Road, Edgewater, MD 21037 (United States); Hintelmann, Holger [Department of Chemistry, Trent University, 1600 West Bank Drive, Peterborough, Ontario, K9J 7B8 (Canada)

    2008-07-15

    Our objective was to examine how the behavior of atmospheric mercury (Hg) deposited to boreal lake mesocosms changed over time. We added inorganic Hg enriched in a different stable isotope in each of two years, which allowed us to differentiate between Hg added in the first and second year. Although inorganic Hg and methylmercury (MeHg) continued to accumulate in sediments throughout the experiment, the availability of MeHg to the food web declined within one year. This decrease was detected in periphyton, zooplankton, and water mites, but not in gomphid larvae, amphipods, or fish. We suggest that reductions in atmospheric Hg deposition should lead to decreases in MeHg concentrations in biota, but that changes will be more easily detected in short-lived pelagic species than long-lived species associated with benthic food webs. - Mercury deposited to aquatic ecosystems becomes less available for uptake by biota over time.

  2. The role of spatial and temporal radiation deposition in inertial fusion chambers: the case of HiPER

    Science.gov (United States)

    Alvarez, J.; Garoz, D.; Gonzalez-Arrabal, R.; Rivera, A.; Perlado, M.

    2011-05-01

    The first wall armour for the reactor chamber of HiPER will have to face short energy pulses of 5 to 20 MJ mostly in the form of x-rays and charged particles at a repetition rate of 5-10 Hz. Armour material and chamber dimensions have to be chosen to avoid/minimize damage to the chamber, ensuring the proper functioning of the facility during its planned lifetime. The maximum energy fluence that the armour can withstand without risk of failure, is determined by temporal and spatial deposition of the radiation energy inside the material. In this paper, simulations on the thermal effect of the radiation-armour interaction are carried out with an increasing definition of the temporal and spatial deposition of energy to prove their influence on the final results. These calculations will lead us to present the first values of the thermo-mechanical behaviour of the tungsten armour designed for the HiPER project under a shock ignition target of 48 MJ. The results will show that only the crossing of the plasticity limit in the first few micrometres might be a threat after thousands of shots for the survivability of the armour.

  3. Type-I ELM power deposition profile width and temporal shape in JET

    NARCIS (Netherlands)

    Eich, T.; Thomsen, H.; Fundamenski, W.; Arnoux, G.; Brezinsek, S.; Devaux, S.; Herrmann, A.; Jachmich, S.; Rapp, J.

    2011-01-01

    A new infra red camera (IR) for high resolution infra red studies for the outer divertor target plate in JET has been installed. Shot integrated energy balance between tile embedded thermocouples and IR based estimation of deposited energy on the outer tile gives fair agreement in the range of

  4. Temporal trends in spheroidal carbonaceous particle deposition derived from annual sediment traps and lake sediment cores and their relationship with non-marine sulphate.

    Science.gov (United States)

    Rose, N L; Monteith, D T

    2005-09-01

    Spheroidal carbonaceous particles (SCPs) provide an unambiguous indication of atmospherically deposited contamination from industrial sources. SCP data from a 12 year annual sediment trapping and coring programme at 14 lakes based on the UK Acid Waters Monitoring Network, were used to consider temporal trends in deposition and to compare these with measured non-marine sulphate fluxes. Results show good temporal coherence across a broad area of northern UK and that SCP deposition levels and are now at their lowest since the 1940s, in agreement with modelled sulphate data. SCP fluxes show reasonable linearity with measured non-marine sulphate depositional fluxes from the nearest UK Acid Deposition Monitoring Network sites, especially over the post-flue-gas desulphurisation period, but comparisons prior to 1972 are not possible due to lack of data. We speculate on whether palaeolimnological SCP data might be used to reconstruct the history of non-marine sulphate fluxes from industrial sources.

  5. Ozone deposition in a mixed forest ecosystem - temporal variation and removal processes

    Science.gov (United States)

    Pokorska, Olga; Gruening, Carsten; Goded, Ignacio

    2016-04-01

    Forests are a major sink for tropospheric ozone, however the fate of ozone within the forest canopy is still not well understood. In this study we will present results of 3 years ozone flux measurements at eddy covariance flux tower in Ispra (Northern Italy) over mixed forest ecosystem. The main tree species in this ecosystem are Quercus robur (80%), Alnus glutinosa (10%), Populus alba (5%) and Carpinus betulus (3%). The measurements were carried out continuously from January 2013 till December 2015. Flux measurements at the canopy level with the eddy covariance technique were complemented with measurements of meteorological parameters and measurements of VOCs (Volatile Organic Compounds) using PTR-MS (Proton Transfer Reaction - Mass Spectrometry) during an intensive observation period. Continuous measurements produced a big dataset which allowed us to investigate the controls on ozone fluxes and to do multiyear comparisons. Patterns of ozone concentration, ozone fluxes and ozone deposition velocity over forest canopy will be presented in relation to physiological activity of the trees and time of the year. Current research is mainly aimed at better understanding of the contribution of destruction processes within the canopy. Therefore, the collected data were used to calculate the partitioning of total ozone fluxes between stomatal and non-stomatal sinks. We found that the stomatal uptake contributed less that non-stomatal uptake to the total ozone flux during the growing seasons. In particular, non-stomatal ozone removal by reactions with isoprene and other VOCs will be discussed. We will present contribution and change of individual ozone deposition sinks over the years in response to environmental parameters.

  6. Innovative 'Artificial Mussels' technology for assessing spatial and temporal distribution of metals in Goulburn-Murray catchments waterways, Victoria, Australia: effects of climate variability (dry vs. wet years).

    Science.gov (United States)

    Kibria, Golam; Lau, T C; Wu, Rudolf

    2012-12-01

    The "Artificial mussel" (AM), a novel passive sampling technology, was used for the first time in Australia in freshwater to monitor and assess the risk of trace metals (Cd, Cu, Hg, Pb, and Zn). AMs were deployed at 10 sites within the Goulburn-Murray Water catchments, Victoria, Australia during a dry year (2009-2010) and a wet year (2010-2011). Our results showed that the AMs accumulated all the five metals. Cd, Pb, Hg were detected during the wet year but below detection limits during the dry year. At some sites close to orchards, vine yards and farming areas, elevated levels of Cu were clearly evident during the dry year, while elevated levels of Zn were found during the wet year; the Cu indicates localized inputs from the agricultural application of copper fungicide. The impacts from old mines were significantly less compared 'hot spots'. Our study demonstrated that climate variability (dry, wet years) can influence the metal inputs to waterways via different transport pathways. Using the AMs, we were able to identify various 'hot spots' of heavy metals, which may pose a potential risk to aquatic ecosystems (sub-lethal effects to fish) and public (via food chain metal bioaccumulation and biomagnification) in the Goulburn-Murray Water catchments. The State Protection Policy exempted artificial channels and drains from protection of beneficial use (including protection of aquatic ecosystems) and majority of sites ('hot spots') were located within artificial irrigation channels. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Identification of Trend in Spatial and Temporal Dry and Wet Periods in Northwest of Iran Based on SPI and RAI Indices

    Directory of Open Access Journals (Sweden)

    Majid Montaseri

    2017-02-01

    Full Text Available Introduction: Droughts are natural extreme phenomena, which frequently occur around the world. This phenomenon can occur in any region, but its effects will be more severe in arid and semi-arid regions. Several studies have highlighted the increasing of droughts trend around the world. The majority of studies in assessing the trend of time series are based on basic Mann-Kendall or Spearman's methods and no serious attention has been paid to the impact of autocorrelation coefficient on time series. However, limited numbers of studies have included the lag-1 autocorrelation coefficient and its impacts on the time series trend. The aim of this study was to investigate the trend of dry and wet periods in northwest of Iran using Mann-Kendall trend test with removing all significant autocorrelations coefficients based on SPI and RAI drought indices. Materials and Methods: Study area has a region of 334,000 square kilometers, with wet, arid and semiarid climate, located in the northwest of Iran. The rainfall data were collected from 39 synoptic stations with average rainfall of 146 mm as the minimum of Gom station, and the highest annual rainfall of 1687 mm, in the Bandaranzali station. In this study, Standardized Precipitation Index (SPI and Rainfall Anomaly Index (RAI were used for trend analysis of dry and wet periods. SPI was developed by McKee et al. in 1993 to determine and monitor droughts. This index is able to determine the wet and dry situations for a specific time scale for each location using rainfall data. RAI index was developed by Van Rooy in 1965 to calculate the deviation of rainfall from the normal amount of rainfall and it evaluates monthly or annual rainfall on a linear scale resulting from a data series. Then, correlation coefficients of time series of these drought indices with different lags were determined for check the dependence or independence of the SPI and RAI values. Finally, based on dependence or independence of the time

  8. A 20-year simulated climatology of global dust aerosol deposition.

    Science.gov (United States)

    Zheng, Yu; Zhao, Tianliang; Che, Huizheng; Liu, Yu; Han, Yongxiang; Liu, Chong; Xiong, Jie; Liu, Jianhui; Zhou, Yike

    2016-07-01

    Based on a 20-year (1991-2010) simulation of dust aerosol deposition with the global climate model CAM5.1 (Community Atmosphere Model, version 5.1), the spatial and temporal variations of dust aerosol deposition were analyzed using climate statistical methods. The results indicated that the annual amount of global dust aerosol deposition was approximately 1161±31Mt, with a decreasing trend, and its interannual variation range of 2.70% over 1991-2010. The 20-year average ratio of global dust dry to wet depositions was 1.12, with interannual variation of 2.24%, showing the quantity of dry deposition of dust aerosol was greater than dust wet deposition. High dry deposition was centered over continental deserts and surrounding regions, while wet deposition was a dominant deposition process over the North Atlantic, North Pacific and northern Indian Ocean. Furthermore, both dry and wet deposition presented a zonal distribution. To examine the regional changes of dust aerosol deposition on land and sea areas, we chose the North Atlantic, Eurasia, northern Indian Ocean, North Pacific and Australia to analyze the interannual and seasonal variations of dust deposition and dry-to-wet deposition ratio. The deposition amounts of each region showed interannual fluctuations with the largest variation range at around 26.96% in the northern Indian Ocean area, followed by the North Pacific (16.47%), Australia (9.76%), North Atlantic (9.43%) and Eurasia (6.03%). The northern Indian Ocean also had the greatest amplitude of interannual variation in dry-to-wet deposition ratio, at 22.41%, followed by the North Atlantic (9.69%), Australia (6.82%), North Pacific (6.31%) and Eurasia (4.36%). Dust aerosol presented a seasonal cycle, with typically strong deposition in spring and summer and weak deposition in autumn and winter. The dust deposition over the northern Indian Ocean exhibited the greatest seasonal change range at about 118.00%, while the North Atlantic showed the lowest seasonal

  9. Nanoscale Wet Etching of Physical-Vapor-Deposited Titanium Nitride and Its Application to Sub-30-nm-Gate-Length Fin-Type Double-Gate Metal-Oxide-Semiconductor Field-Effect Transistor Fabrication

    Science.gov (United States)

    Yongxun Liu,; Takahiro Kamei,; Kazuhiko Endo,; Shinichi O'uchi,; Junichi Tsukada,; Hiromi Yamauchi,; Tetsuro Hayashida,; Yuki Ishikawa,; Takashi Matsukawa,; Kunihiro Sakamoto,; Atsushi Ogura,; Meishoku Masahara,

    2010-06-01

    The nanoscale wet etching of physical-vapor-deposited (PVD) titanium nitride (TiN) and its application to sub-30-nm-gate-length fin-type double-gate metal-oxide-semiconductor field-effect transistor (FinFET) fabrication are systematically investigated. It is experimentally found that PVD-TiN side-etching depth can be controlled to be one-half of PVD-TiN thickness with precise time control using an ammonium hydroxide (NH4OH) : hydrogen peroxide (H2O2) : deionized water (H2O) = 1 : 2 : 5 solution at 60 °C. Using the developed nanoscale PVD-TiN wet etching technique, sub-30-nm-physical-gate-length FinFETs, 100-nm-tall fin-channel complementary MOS (CMOS) inverters and static random access memory (SRAM) half-cells have successfully been fabricated and demonstrated. These experimental results indicate that the developed nanoscale PVD-TiN wet etching technique is very useful for tall fin-channel CMOS fabrication.

  10. Vaginitis test - wet mount

    Science.gov (United States)

    Wet prep - vaginitis; Vaginosis - wet mount; Trichomoniasis - wet mount; Vaginal candida - wet mount ... a rash, painful intercourse, or odor after intercourse. Trichomoniasis , a sexually transmitted disease. Vaginal yeast infection .

  11. Fission products in National Atmospheric Deposition Program—Wet deposition samples prior to and following the Fukushima Dai-Ichi Nuclear Power Plant incident, March 8?April 5, 2011

    Science.gov (United States)

    Wetherbee, Gregory A.; Debey, Timothy M.; Nilles, Mark A.; Lehmann, Christopher M.B.; Gay, David A.

    2012-01-01

    Radioactive isotopes I-131, Cs-134, or Cs-137, products of uranium fission, were measured at approximately 20 percent of 167 sampled National Atmospheric Deposition Program monitoring sites in North America (primarily in the contiguous United States and Alaska) after the Fukushima Dai-Ichi Nuclear Power Plant incident on March 12, 2011. Samples from the National Atmospheric Deposition Program were analyzed for the period of March 8-April 5, 2011. Calculated 1- or 2-week radionuclide deposition fluxes at 35 sites from Alaska to Vermont ranged from 0.47 to 5,100 Becquerels per square meter during the sampling period of March 15-April 5, 2011. No fission-product isotopes were measured in National Atmospheric Deposition Program samples obtained during March 8-15, 2011, prior to the arrival of contaminated air in North America.

  12. One-step wet chemical deposition of NiO from the electrochemical reduction of nitrates in ionic liquid based electrolytes

    OpenAIRE

    Azaceta, Eneko; Tuyen, Ngo T.; Pickup, David F.; Rogero, Celia; Ortega, J. Enrique; Miguel, Óscar; Grande, Hans-Jurgen; Tena-Zaera, Ramón

    2013-01-01

    Aprotic PYR14TFSI (1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)) ionic liquid served to develop a new electrochemical route for one-step deposition of NiO from PYR14NO3 reduction (1-butyl-1-methylpyrrolidinium nitrate) in a Ni(TFSI)2 (Nickel (II) bis(trifluoromethanesulfonyl)imide) containing electrolyte. The high solubility of the novel PYR14NO3 salt in PYR14TFSI (>0.1 M) in comparison with other oxygenated precursors such as oxygen gas, NaNO 3 or KNO3 (i.e. 10-15 mM) allows t...

  13. Spatial variability and temporal stability of throughfall deposition under beech (Fagus sylvatica L.) in relationship to canopy structure

    Energy Technology Data Exchange (ETDEWEB)

    Staelens, Jeroen [Ghent University, Laboratory of Forestry, Geraardsbergsesteenweg 267, 9090 Gontrode (Belgium)]. E-mail: jeroen_staelens@yahoo.com; De Schrijver, An [Ghent University, Laboratory of Forestry, Geraardsbergsesteenweg 267, 9090 Gontrode (Belgium); Verheyen, Kris [Ghent University, Laboratory of Forestry, Geraardsbergsesteenweg 267, 9090 Gontrode (Belgium); Verhoest, Niko E.C. [Ghent University, Laboratory of Hydrology and Water Management, Coupure links 653, 9000 Gent (Belgium)

    2006-07-15

    Although the spatial variability of throughfall (TF) in forest ecosystems can have important ecological implications, little is known about the driving factors of within-stand TF variability, particularly in deciduous forests. While the spatial variability of TF water amount and H{sup +} deposition under a dominant beech (Fagus sylvatica L.) tree was significantly higher in the leafed period than in the leafless period, the spatial TF deposition patterns of most major ions were similar in both periods. The semiannual TF depositions of all ions other than H{sup +} were significantly positively correlated (r = 0.68-0.90, p < 0.05) with canopy structure above sample locations throughout the entire year. The amounts of TF water and H{sup +} deposition during the leafed period were negatively correlated with branch cover. We conclude that the spatial heterogeneity of ion deposition under beech was significantly affected by leaves in the growing period and by branches in non-foliated conditions. - Ion deposition under a deciduous beech tree was strongly affected by the canopy structure throughout the entire year.

  14. Wet-Chemical Surface Texturing of Sputter-Deposited ZnO:Al Films as Front Electrode for Thin-Film Silicon Solar Cells

    Directory of Open Access Journals (Sweden)

    Xia Yan

    2015-01-01

    Full Text Available Transparent conductive oxides (TCOs play a major role as the front electrodes of thin-film silicon (Si solar cells, as they can provide optical scattering and hence improved photon absorption inside the devices. In this paper we report on the surface texturing of aluminium-doped zinc oxide (ZnO:Al or AZO films for improved light trapping in thin-film Si solar cells. The AZO films are deposited onto soda-lime glass sheets via pulsed DC magnetron sputtering. Several promising AZO texturing methods are investigated using diluted hydrochloric (HCl and hydrofluoric acid (HF, through a two-step etching process. The developed texturing procedure combines the advantages of the HCl-induced craters and the smaller and jagged—but laterally more uniform—features created by HF etching. In the two-step process, the second etching step further enhances the optical haze, while simultaneously improving the uniformity of the texture features created by the HCl etch. The resulting AZO films show large haze values of above 40%, good scattering into large angles, and a surface angle distribution that is centred at around 30°, which is known from the literature to provide efficient light trapping for thin-film Si solar cells.

  15. Quantitative and simultaneous analysis of the polarity of polycrystalline ZnO seed layers and related nanowires grown by wet chemical deposition

    Energy Technology Data Exchange (ETDEWEB)

    Guillemin, Sophie; Parize, Romain; Carabetta, Joseph; Cantelli, Valentina; Albertini, David; Gautier, Brice; Brémond, Georges; Fong, Dillon D.; Renevier, Hubert; Consonni, Vincent

    2017-01-30

    The polarity in ZnO nanowires is an important issue since it strongly affects surface configuration and reactivity, nucleation and growth, electro-optical properties, and nanoscaleengineering device performances. However, measuring statistically the polarity of ZnO nanowire arrays grown by chemical bath deposition and elucidating its correlation with the polarity of the underneath polycrystalline ZnO seed layer grown by the sol–gel process represents a major difficulty. To address that issue, we combine resonant x-ray diffraction (XRD) at Zn K-edge using synchrotron radiation with piezoelectric force microscopy and polarity-sensitive chemical etching to statistically investigate the polarity of more than 107 nano-objects both on the macroscopic and local microscopic scales, respectively. By using high temperature annealing under an argon atmosphere, it is shown that the compact, highly c-axis oriented ZnO seed layer is more than 92% Zn-polar and that only a few small O-polar ZnO grains with an amount less than 8% are formed. Correlatively, the resulting ZnO nanowires are also found to be Zn-polar, indicating that their polarity is transferred from the c-axis oriented ZnO grains acting as nucleation sites in the seed layer. These findings pave the way for the development of new strategies to form unipolar ZnO nanowire arrays as a requirement for a number of nanoscaleengineering devices like piezoelectric nanogenerators. They also highlight the great advantage of resonant XRD as a macroscopic, non-destructive method to simultaneously and statistically measure the polarity of ZnO nanowire arrays and of the underneath ZnO seed layer.

  16. Quantitative and simultaneous analysis of the polarity of polycrystalline ZnO seed layers and related nanowires grown by wet chemical deposition

    Science.gov (United States)

    Guillemin, Sophie; Parize, Romain; Carabetta, Joseph; Cantelli, Valentina; Albertini, David; Gautier, Brice; Brémond, Georges; Fong, Dillon D.; Renevier, Hubert; Consonni, Vincent

    2017-03-01

    The polarity in ZnO nanowires is an important issue since it strongly affects surface configuration and reactivity, nucleation and growth, electro-optical properties, and nanoscale-engineering device performances. However, measuring statistically the polarity of ZnO nanowire arrays grown by chemical bath deposition and elucidating its correlation with the polarity of the underneath polycrystalline ZnO seed layer grown by the sol-gel process represents a major difficulty. To address that issue, we combine resonant x-ray diffraction (XRD) at Zn K-edge using synchrotron radiation with piezoelectric force microscopy and polarity-sensitive chemical etching to statistically investigate the polarity of more than 107 nano-objects both on the macroscopic and local microscopic scales, respectively. By using high temperature annealing under an argon atmosphere, it is shown that the compact, highly c-axis oriented ZnO seed layer is more than 92% Zn-polar and that only a few small O-polar ZnO grains with an amount less than 8% are formed. Correlatively, the resulting ZnO nanowires are also found to be Zn-polar, indicating that their polarity is transferred from the c-axis oriented ZnO grains acting as nucleation sites in the seed layer. These findings pave the way for the development of new strategies to form unipolar ZnO nanowire arrays as a requirement for a number of nanoscale-engineering devices like piezoelectric nanogenerators. They also highlight the great advantage of resonant XRD as a macroscopic, non-destructive method to simultaneously and statistically measure the polarity of ZnO nanowire arrays and of the underneath ZnO seed layer.

  17. Letter to the editor: Critical assessments of the current state of scientific knowledge, terminology, and research needs concerning the ecological effects of elevated atmospheric nitrogen deposition in China

    Science.gov (United States)

    Pan, Yuepeng; Liu, Yongwen; Wentworth, Gregory R.; Zhang, Lin; Zhao, Yuanhong; Li, Yi; Liu, Xuejun; Du, Enzai; Fang, Yunting; Xiao, Hongwei; Ma, Hongyuan; Wang, Yuesi

    2017-03-01

    In a publication in Atmospheric Environment (http://dx.doi.org/10.1016/j.atmosenv.2015.10.081), Gu et al. (2015) estimated that "the total nitrogen (N) deposition in 2010 was 2.32 g N m-2 yr-1" in China. This value is comparable with previous estimations based on a synthesized dataset of wet/bulk inorganic N deposition observations, which underestimates the total N deposition since their algorithm (equations (2) and (3) in their paper) does not account for dry deposition of NH3, HNO3, NOx and wet/dry deposition of HONO and organic nitrogen (e.g. amines, amides, PAN). Indeed, Gu et al. (2015) mixed the terminology of wet/bulk deposition and total deposition. Another flawed assumption by Gu et al. (2015) is that all inorganic N in precipitation estimated by their algorithm originates from fertilizer and coal combustion. This is incorrect and almost certainly causes biases in the spatial and temporal distribution of estimated wet/bulk inorganic N deposition (Fig. 5 in their paper), further considering the fact that they neglected important N sources like livestock and they did not consider the nonlinearity between various sources and deposition. Besides the input data on N deposition, the model validation (Sect. 2.3.2) described in their paper also requires clarification because the detailed validation information about the time series of observational dataset versus modeling results was not given. As a result of these combined uncertainties in their estimation of N deposition and the lack of detail for model-measurement comparison, their estimates of the impacts of N deposition on carbon storage in Chinese forests may need further improvement. We suggest the clarification of the terminology regarding N deposition, especially for wet deposition, bulk deposition, gaseous and particulate dry deposition or total deposition since the accurate distinction between these terms is crucial to investigating and estimating the effects of N deposition on ecosystems.

  18. Temporal Changes in Aqu/C60 Physical-Chemical, Deposition, and Transport Characteristics in Aqueous Systems

    Science.gov (United States)

    Little is known about how temporal changes in the physical–chemical properties of C60 aggregates formed in aqueous systems (termed aqu/C60) can impact transport pathways contributing to ecological exposures. In this study three aqu/C60 suspensions of short-term (100 days), interm...

  19. Branch bark of holm oak (Quercus ilex L.) for reconstructing the temporal variations of atmospheric deposition of hexavalent chromium.

    Science.gov (United States)

    Drava, Giuliana; Anselmo, Marco; Brignole, Daniele; Giordani, Paolo; Minganti, Vincenzo

    2017-03-01

    The bark from the annual segments of the branches of holm oak (Quercus ilex L.) is exposed to trace element deposition for a known period of time and thus it is a possible candidate as a bioindicator for reconstructing historical changes in pollution. A series of samples were analysed for Cr(VI) concentration by electrothermal atomic absorption spectrometry (ET-AAS) after selective extraction in a sodium carbonate solution. In this way the atmospheric deposition of Cr(VI) was reconstructed from 2001 to 2010 in an area where an industrial plant produced Cr(VI) compounds until 2003. The present study shows the potential of this type of sample as a natural archive for persistent pollutants, useful for monitoring changes that occur before a monitoring programme is established, with the advantage of being easy to collect almost everywhere. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Effect of superhydrophobic surface morphology on evaporative deposition patterns

    Science.gov (United States)

    Dicuangco, Mercy; Dash, Susmita; Weibel, Justin A.; Garimella, Suresh V.

    2014-05-01

    Prediction and active control of the spatial distribution of particulate deposits obtained from sessile droplet evaporation are vital in printing, nanostructure assembly, biotechnology, and other applications that require localized deposits. This Letter presents surface wettability-based localization of evaporation-driven particulate deposition and the effect of superhydrophobic surface morphology on the distribution of deposits. Sessile water droplets containing suspended latex particles are evaporated on non-wetting textured surfaces with varying microstructure geometry at ambient conditions. The droplets are visualized throughout the evaporation process to track the temporal evolution of contact radius and apparent contact angle. The resulting particle deposits on the substrates are quantitatively characterized. The experimental results show that superhydrophobic surfaces suppress contact-line deposition during droplet evaporation, thereby providing an effective means of localizing the deposition of suspended particles. A correlation between deposit size and surface morphology, explained in terms of the interface pressure balance at the transition between wetting states, reveals an optimum surface morphology for minimizing the deposit coverage area.

  1. Investigation of spatial and temporal metal atmospheric deposition in France through lichen and moss bioaccumulation over one century

    Energy Technology Data Exchange (ETDEWEB)

    Agnan, Y., E-mail: yannick.agnan@biogeochimie.fr; Séjalon-Delmas, N.; Claustres, A.; Probst, A., E-mail: anne.probst@ensat.fr

    2015-10-01

    Lichens and mosses were used as biomonitors to assess the atmospheric deposition of metals in forested ecosystems in various regions of France. The concentrations of 17 metals/metalloids (Al, As, Cd, Co, Cr, Cs, Cu, Fe, Mn, Ni, Pb, Sb, Sn, Sr, Ti, V, and Zn) indicated overall low atmospheric contamination in these forested environments, but a regionalism emerged from local contributions (anthropogenic activities, as well as local lithology). Taking into account the geochemical background and comparing to Italian data, the elements from both natural and anthropogenic activities, such as Cd, Pb, or Zn, did not show any obvious anomalies. However, elements mainly originating from lithogenic dust (e.g., Al, Fe, Ti) were more prevalent in sparse forests and in the Southern regions of France, whereas samples from dense forests showed an accumulation of elements from biological recycling (Mn and Zn). The combination of enrichment factors and Pb isotope ratios between current and herbarium samples indicated the historical evolution of metal atmospheric contamination: the high contribution of coal combustion beginning 150 years ago decreased at the end of the 20th century, and the influence of car traffic during the latter observed period decreased in the last few decades. In the South of France, obvious local influences were well preserved during the last century. - Highlights: • A century of metal deposition was assessed by lichens and mosses in France. • A regional forest cover-dependent geochemical background signature was evidenced. • The anthropogenic contribution was low but stronger in the North-Eastern region. • Changes in the nature of atmospheric deposition were evidenced since the 19th century. • Pb isotopes traced a conservative specific contamination in SW France over a century.

  2. Temporal evolution of bacterial communities associated with the in situ wetland-based remediation of a marine shore porphyry copper tailings deposit.

    Science.gov (United States)

    Diaby, N; Dold, B; Rohrbach, E; Holliger, C; Rossi, P

    2015-11-15

    Mine tailings are a serious threat to the environment and public health. Remediation of these residues can be carried out effectively by the activation of specific microbial processes. This article presents detailed information about temporal changes in bacterial community composition during the remediation of a section of porphyry copper tailings deposited on the Bahía de Ite shoreline (Peru). An experimental remediation cell was flooded and transformed into a wetland in order to prevent oxidation processes, immobilizing metals. Initially, the top oxidation zone of the tailings deposit displayed a low pH (3.1) and high concentrations of metals, sulfate, and chloride, in a sandy grain size geological matrix. This habitat was dominated by sulfur- and iron-oxidizing bacteria, such as Leptospirillum spp., Acidithiobacillus spp., and Sulfobacillus spp., in a microbial community which structure resembled acid mine drainage environments. After wetland implementation, the cell was water-saturated, the acidity was consumed and metals dropped to a fraction of their initial respective concentrations. Bacterial communities analyzed by massive sequencing showed time-dependent changes both in composition and cell numbers. The final remediation stage was characterized by the highest bacterial diversity and evenness. Aside from classical sulfate reducers from the phyla δ-Proteobacteria and Firmicutes, community structure comprised taxa derived from very diverse habitats. The community was also characterized by an elevated proportion of rare phyla and unaffiliated sequences. Numerical ecology analysis confirmed that the temporal population evolution was driven by pH, redox, and K. Results of this study demonstrated the usefulness of a detailed follow-up of the remediation process, not only for the elucidation of the communities gradually switching from autotrophic, oxidizing to heterotrophic and reducing living conditions, but also for the long term management of the remediation

  3. Ammonia emissions in the United States, European Union, and China derived by high-resolution inversion of ammonium wet deposition data: Interpretation with a new agricultural emissions inventory (MASAGE_NH3)

    Science.gov (United States)

    Paulot, F.; Jacob, D. J.; Pinder, R. W.; Bash, J. O.; Travis, K.; Henze, D. K.

    2014-04-01

    We use the adjoint of a global 3-D chemical transport model (GEOS-Chem) to optimize ammonia (NH3) emissions in the U.S., European Union, and China by inversion of 2005-2008 network data for NH4+ wet deposition fluxes. Optimized emissions are derived on a 2° × 2.5° grid for individual months and years. Error characterization in the optimization includes model errors in precipitation. Annual optimized emissions are 2.8 Tg NH3-N a-1 for the contiguous U.S., 3.1 Tg NH3-N a-1 for the European Union, and 8.4 Tg NH3-N a-1 for China. Comparisons to previous inventories for the U.S. and European Union show consistency (˜±15%) in annual totals but some large spatial and seasonal differences. We develop a new global bottom-up inventory of NH3 emissions (Magnitude And Seasonality of Agricultural Emissions model for NH3 (MASAGE_NH3)) to interpret the results of the adjoint optimization. MASAGE_NH3 provides information on the magnitude and seasonality of NH3 emissions from individual crop and livestock sources on a 0.5° × 0.5° grid. We find that U.S. emissions peak in the spring in the Midwest due to corn fertilization and in the summer elsewhere due to manure. The seasonality of European emissions is more homogeneous with a well-defined maximum in spring associated with manure and mineral fertilizer application. There is some evidence for the effect of European regulations of NH3 emissions, notably a large fall decrease in northern Europe. Emissions in China peak in summer because of the summertime application of fertilizer for double cropping.

  4. Spatial distributions of radionuclides deposited onto ground soil around the Fukushima Dai-ichi Nuclear Power Plant and their temporal change until December 2012.

    Science.gov (United States)

    Mikami, Satoshi; Maeyama, Takeshi; Hoshide, Yoshifumi; Sakamoto, Ryuichi; Sato, Shoji; Okuda, Naotoshi; Demongeot, Stéphanie; Gurriaran, Rodolfo; Uwamino, Yoshitomo; Kato, Hiroaki; Fujiwara, Mamoru; Sato, Tetsuro; Takemiya, Hiroshi; Saito, Kimiaki

    2015-01-01

    Spatial distributions and temporal changes of radioactive fallout released by the Fukushima Dai-ichi Nuclear Power Plant accident have been investigated by two campaigns with three measurement schedules. The inventories (activities per unit area) of the radionuclides deposited onto ground soil were measured using portable gamma-ray spectrometers at nearly 1000 locations (at most) per measurement campaign. Distribution maps of the inventories of (134)Cs, (137)Cs, and (110m)Ag as of March, September, and December 2012 were constructed. No apparent temporal change of the radionuclide inventories was observed from March to December 2012. Weathering effects (e.g., horizontal mobility) were not noticeable during this period. Spatial dependence in the ratios of (134)Cs/(137)Cs and (110m)Ag/(137)Cs were observed in the Tohoku and Kanto regions. The detailed maps of (134)Cs and (137)Cs as of September 2012 and December 2012 were constructed using the relationship between the air dose rate and the inventory. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  5. A new geoarchaeology of Aboriginal artefact deposits in western NSW, Australia: establishing spatial and temporal geomorphic controls on the surface archaeological record

    Science.gov (United States)

    Fanning, Patricia C.; Holdaway, Simon J.; Rhodes, Ed J.

    2008-10-01

    Surface deposits of stone artefacts are the most common feature of the Australian Aboriginal archaeological record, but they remain difficult for archaeologists to interpret. Among the many reasons is a lack of understanding of geomorphic processes that have exposed the artefacts at the surface. We describe research on the geomorphic environments in arid Australia from which we have developed a new geoarchaeological framework for describing and analysing surface artefact deposits. Optically Stimulated Luminescence dating of sediments upon which the artefacts currently rest demonstrates that the landscape, and the archaeological record it preserves, is spatially and temporally discontinuous. Exposure and/or burial of artefacts is controlled by geomorphic processes operating on timescales ranging from a few decades to thousands of years and spatial scales of tens to many thousands of square meters. These same processes, operating on similar scales, also determine whether or not artefact scatters are preserved in the contemporary landscape or in the sedimentary record of past landscapes, and hence whether or not they become part of the archaeological record. Models of settlement behavior in hunter-gatherer peoples that are largely derived from analysis of surface 'sites' must take account of these discontinuities.

  6. Estimates of the atmospheric deposition of sulfur and nitrogen species: Clean Air Status and Trends Network, 1990-2000

    Energy Technology Data Exchange (ETDEWEB)

    Baumgardner, R.E. Jr.; Lavery, T.F.; Rogers, C.M; Isil, S.S. [US Environmental Protection Agency, Research Triangle Park, NC (United States)

    2002-06-15

    The Clean Air Status and Trends Network (CASTNet) was established by the US EPA in response to the requirements of the 1990 Clean Air Act Amendment to assess and report on geographic patterns and long-term, temporal trends in ambient air pollution and acid deposition in order to gauge the effectiveness of current and future mandated emission reductions. This paper presents an analysis of the spatial patterns of deposition of sulfur and nitrogen pollutants for the period 1990-2000. Estimates of deposition are provided for two 4-yr periods: 1990-1993 and 1997-2000 selected to contrast deposition before and after the large decrease in SO{sub 2} emissions that occurred in 1995. An analysis of the deposition estimates showed a significant decline in sulfur deposition and no change in nitrogen deposition. The highest rates of sulfur deposition were observed in the Ohio River Valley and downwind states. This region also observed the largest decline in sulfur deposition. The highest rates of nitrogen deposition were observed in the Midwest from Illinois to southern New York State. Sulfur and nitrogen deposition fluxes were significantly higher in the eastern United States as compared to the western sites. Dry deposition contributed approximately 38% of total sulfur deposition and 30% of total nitrogen deposition in the eastern United States. Percentages are similar for the two 4-yr periods. Wet sulfate and dry SO{sub 2} depositions were the largest contributors to sulfur deposition. Wet nitrate, wet ammonium, and dry HNO{sub 3} deposition were the largest contributors to nitrogen deposition. 40 refs., 14 figs., 4 tabs.

  7. Zircon petrochronology reveals the temporal link between porphyry systems and the magmatic evolution of their hidden plutonic roots (the Eocene Coroccohuayco deposit, Peru)

    Science.gov (United States)

    Chelle-Michou, Cyril; Chiaradia, Massimo; Ovtcharova, Maria; Ulianov, Alexey; Wotzlaw, Jörn-Frederik

    2014-06-01

    We present zircon geochronologic (LA-ICPMS and ID-TIMS), trace element and Hf isotopic evidence for a complex evolution of the plutonic roots of the Eocene Coroccohuayco porphyry system, southern Peru. LA-ICPMS U-Pb dating has initially been carried out to optimize grain selection for subsequent high-precision ID-TIMS dating and to characterize crustal assimilation (xenocrystic cores). This combined in-situ and whole-grain U-Pb dating of the same grains has been further exploited to derive a robust temporal interpretation of the complex magmatic system associated with the Coroccohuayco porphyry-skarn deposit. Our data reveal that a heterogeneous gabbrodioritic complex was emplaced at ca. 40.4 Ma and was followed by a nearly 5 Ma-long magmatic lull until the emplacement of dacitic porphyry stocks and dykes associated with the mineralizing event at ca. 35.6 Ma. However, at the sample scale, zircons from the porphyries provide insight into a 2 Ma-long lived “hidden” magmatism (probably at 4-9 km paleodepth) prior to porphyry intrusion and mineralization for which no other evidence can be found on the surface today. These dates together with zircon trace element analysis and Hf isotopes argue for the development of a long-lived magmatic system dominated by amphibole fractionation with an increasing amount of crustal assimilation and the development of a large and sustained thermal anomaly. The system was probably rejuvenated at an increasing rate from 37.5 to 35.6 Ma with injection of fresh and oxidized magma from the lower crust, which caused cannibalism and remelting of proto-plutons. The porphyry intrusions at Coroccohuayco were emplaced at the peak thermal conditions of this upper crustal magma chamber, which subsequently cooled and expelled ore fluids. Zircon xenocrysts and Hf isotopes in the porphyritic rocks suggest that this large upper crustal system evolved at stratigraphic levels corresponding to Triassic sediments similar to the Mitu group that may be

  8. Hydrothermal titanite from the Chengchao iron skarn deposit: temporal constraints on iron mineralization, and its potential as a reference material for titanite U-Pb dating

    Science.gov (United States)

    Hu, Hao; Li, Jian-Wei; McFarlane, Christopher R. M.

    2017-09-01

    Uranium-lead isotopes and trace elements of titanite from the Chengchao iron skarn deposit (Daye district, Eastern China), located along the contact zones between Triassic marine carbonates and an early Cretaceous intrusive complex consisting of granite and quartz diorite, were analyzed using laser ablation inductively coupled plasma mass spectrometry to provide temporal constraints on iron mineralization and to evaluate its potential as a reference material for titanite U-Pb geochronology. Titanite grains from mineralized endoskarn have simple growth zoning patterns, exhibit intergrowth with magnetite, diopside, K-feldspar, albite and actinolite, and typically contain abundant primary two-phase fluid inclusions. These paragenetic and textural features suggest that these titanite grains are of hydrothermal origin. Hydrothermal titanite is distinct from the magmatic variety from the ore-related granitic intrusion in that it contains unusually high concentrations of U (up to 2995 ppm), low levels of Th (12.5-453 ppm), and virtually no common Pb. The REE concentrations are much lower, as are the Th/U and Lu/Hf ratios. The hydrothermal titanite grains yield reproducible uncorrected U-Pb ages ranging from 129.7 ± 0.7 to 132.1 ± 2.7 Ma (2σ), with a weighted mean of 131.2 ± 0.2 Ma [mean standard weighted deviation (MSWD) = 1.7] that is interpreted as the timing of iron skarn mineralization. This age closely corresponds to the zircon U-Pb age of 130.9 ± 0.7 Ma (MSWD = 0.7) determined for the quartz diorite, and the U-Pb ages for zircon and titanite (130.1 ± 1.0 Ma and 131.3 ± 0.3 Ma) in the granite, confirming a close temporal and likely genetic relationship between granitic magmatism and iron mineralization. Different hydrothermal titanite grains have virtually identical uncorrected U-Pb ratios suggestive of negligible common Pb in the mineral. The homogeneous textures and U-Pb characteristics of Chengchao hydrothermal titanite suggest that the mineral might be a

  9. Evidence for Kinetic Limitations as a Controlling Factor of Ge Pyramid Formation: a Study of Structural Features of Ge/Si(001) Wetting Layer Formed by Ge Deposition at Room Temperature Followed by Annealing at 600 °C

    National Research Council Canada - National Science Library

    Storozhevykh, Mikhail S; Arapkina, Larisa V; Yuryev, Vladimir A

    2015-01-01

    .... The experiment has demonstrated that the Ge/Si(001) film formed in the conditions of an isolated system consists of the standard patched wetting layer and large droplike clusters of Ge rather than of huts or domes which appear when a film is grown...

  10. Wetting, Prewetting and Superfluidity

    OpenAIRE

    Taborek, P.

    2009-01-01

    Experiments on adsorption and wetting of quantum fluids (4He and 3He) on weakly binding alkali metal substrates are reviewed. Helium on weak substrates can undergo a variety of phase transitions including wetting, prewetting, layering, and liquid-vapor transitions. Another characteristic feature of weak substrates is the absence of an immobile quasi solid layer which is present on all conventional strong substrates. Both the absence of the immobile layer and the interaction with surface phase...

  11. Seasonal Patterns of Dry Deposition at a High-Elevation Site in the Colorado Rocky Mountains

    Science.gov (United States)

    Oldani, Kaley M.; Mladenov, Natalie; Williams, Mark W.; Campbell, Cari M.; Lipson, David A.

    2017-10-01

    In the Colorado Rocky Mountains, high-elevation barren soils are deficient in carbon (C) and phosphorus (P) and enriched in nitrogen (N). The seasonal variability of dry deposition and its contributions to alpine elemental budgets is critical to understanding how dry deposition influences biogeochemical cycling in high-elevation environments. In this 2 year study, we evaluated dry and wet deposition inputs to the Niwot Ridge Long Term Ecological Research (NWT LTER) site in the Colorado Rocky Mountains. The total organic C flux in wet + dry (including soluble and particulate C) deposition was >30 kg C ha-1 yr-1 and represents a substantial input for this C-limited environment. Our side-by-side comparison of dry deposition collectors with and without marble insert indicated that the insert improved retention of dry deposition by 28%. Annual average dry deposition fluxes of water-soluble organic carbon (4.25 kg C ha-1 yr-1) and other water-soluble constituents, including ammonium (0.16 kg NH4+ha-1 yr-1), nitrate (1.99 kg NO3- ha-1 yr-1), phosphate (0.08 kg PO43- ha-1 yr-1), and sulfate (1.20 kg SO42- ha-1 yr-1), were comparable to those in wet deposition, with highest values measured in the summer. Backward trajectory analyses implicate air masses passing through the arid west and Four Corners, USA, as dominant source areas for dry deposition, especially in spring months. Synchronous temporal patterns of deposition observed at the NWT LTER site and a distant Rocky Mountain National Park Clean Air Status and Trends Network site indicate that seasonal dry deposition patterns are regional phenomena with important implications for the larger Rocky Mountain region.

  12. Wet gas sampling

    Energy Technology Data Exchange (ETDEWEB)

    Welker, T.F.

    1997-07-01

    The quality of gas has changed drastically in the past few years. Most gas is wet with hydrocarbons, water, and heavier contaminants that tend to condense if not handled properly. If a gas stream is contaminated with condensables, the sampling of that stream must be done in a manner that will ensure all of the components in the stream are introduced into the sample container as the composite. The sampling and handling of wet gas is extremely difficult under ideal conditions. There are no ideal conditions in the real world. The problems related to offshore operations and other wet gas systems, as well as the transportation of the sample, are additional problems that must be overcome if the analysis is to mean anything to the producer and gatherer. The sampling of wet gas systems is decidedly more difficult than sampling conventional dry gas systems. Wet gas systems were generally going to result in the measurement of one heating value at the inlet of the pipe and a drastic reduction in the heating value of the gas at the outlet end of the system. This is caused by the fallout or accumulation of the heavier products that, at the inlet, may be in the vapor state in the pipeline; hence, the high gravity and high BTU. But, in fact, because of pressure and temperature variances, these liquids condense and form a liquid that is actually running down the pipe as a stream or is accumulated in drips to be blown from the system. (author)

  13. Wet oxidation of quinoline

    DEFF Research Database (Denmark)

    Thomsen, A.B.; Kilen, H.H.

    1998-01-01

    The influence of oxygen pressure (0.4 and 2 MPa). reaction time (30 and 60 min) and temperature (260 and 280 degrees C) on the wet oxidation of quinoline has been studied. The dominant parameters for the decomposition of quinoline were oxygen pressure and reaction temperature. whereas the reaction...... if low oxygen pressure or long reaction times were used. The reaction products derived from the experiment in which quinoline was mostly decomposed were studied with respect to biological degradation. The results showed that these products were highly digestible under activated sludge treatment....... The combined wet oxidation and biological treatment of reaction products resulted in 91% oxidation of the parent compound to CO2 and water. Following combined wet oxidation and biological treatment the sample showed low toxicity towards Nitrosomonas and no toxicity towards Nitrobacter. (C) 1998 Elsevier...

  14. Wetting of Water on Graphene

    OpenAIRE

    Bera, Bijoyendra; Shahidzadeh, Noushine; Mishra, Himanshu; Bonn, Daniel

    2016-01-01

    The wetting properties of graphene have proven controversial and difficult to assess. The presence of a graphene layer on top of a substrate does not significantly change the wetting properties of the solid substrate, suggesting that a single graphene layer does not affect the adhesion between the wetting phase and the substrate. However, wetting experiments of water on graphene show contact angles that imply a large amount of adhesion. Here, we investigate the wetting of graphene by measurin...

  15. Wetting of real surfaces

    CERN Document Server

    Bormashenko, Edward Yu

    2013-01-01

    The problem of wetting and drop dynamics on various surfaces is very interesting from both the scientificas well as thepractical viewpoint, and subject of intense research.The results are scattered across papers in journals, sothis workwill meet the need for a unifying, comprehensive work.

  16. WET SOLIDS FLOW ENHANCEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Hugo S. Caram; Natalie Foster

    1999-03-30

    The elastic modulus E of wet granular material was found to be of the order of 0.25 MPa, this value does not compare well with the value predicted for a cubic array of spheres under Hertzian contact were the predicted values were in the order of 250 MPa . The strain-stress behavior of a wet granular media was measured using a split Parfitt tensile tester. In all cases the stress increases linearly with distance until the maximum uniaxial tensile stress is reached. The stress then decreases exponentially with distance after this maximum is reached. The linear region indicates that wet solids behave elastically for stresses below the tensile stresses and can store significant elastic energy. The elastic deformation cannot be explained by analyzing the behavior of individual capillary bridges and requires accounting for the deformation of the solids particles. The elastic modulus of the wet granular material remains unexplained. New information was found to support the experimental finding and a first theory to explain the very small elastic modulus is presented. A new model based on the used of the finite element method is being developed.

  17. The Wet Chaparral

    OpenAIRE

    Hope, Audrey Marie

    2017-01-01

    The Wet Chaparral: Poetry at Home (Out There) is an MFA thesis exhibition of new sculptures by Audrey Hope. The thesis paper describes the exhibition, discusses the artist’s personal and artistic motivations, and analyzes writings relevant to the work.

  18. Modeling of temporal patterns and sources of atmospherically transported and deposited pesticides in ecosystems of concern: A case study of toxaphene in the Great Lakes

    Science.gov (United States)

    Li, Rong; Jin, Jiming

    2013-10-01

    have adverse effects on human health and the environment and can be transported through the atmosphere from application sites and deposited to sensitive ecosystems. This study applies a comprehensive multimedia regional pesticide fate and chemical transport modeling system that we developed to investigate the atmospheric transport and deposition of toxaphene to the Great Lakes. Simulated results predict a significant amount of toxaphene (~350 kg) being transported through the atmosphere and deposited into the Great Lakes in the simulation year. Results also show that U.S. residues and global background are major sources to toxaphene deposition into the Great Lakes and atmospheric concentrations in the region. While the U.S. residues are the dominant source in warm months, the background dominates during winter months. In addition, different sources have different influences on the individual Great Lakes due to their proximity and relative geographical positions to the sources; U.S. residues are the dominant source to Lakes Ontario, Erie, Huron, and Michigan, but they are a much less important source to Lake Superior. These results shed light on the mystery that observed toxaphene concentrations in Great Lakes' lake trout and smelt declined between 1982 and 1992 in four of the Great Lakes except Lake Superior. While monthly total depositions to Lakes Ontario, Erie, Huron, and Michigan have clear seasonal variability with much greater values in April, May, and June, monthly total depositions to Lake Superior are more uniformly distributed over the year with comparatively greater levels in cold months.

  19. WET SOLIDS FLOW ENHANCEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2001-03-25

    The yield locus, tensile strength and fracture mechanisms of wet granular materials were studied. The yield locus of a wet material was shifted to the left of that of the dry specimen by a constant value equal to the compressive isostatic stress due to pendular bridges. for materials with straight yield loci, the shift was computed from the uniaxial tensile strength, either measured in a tensile strength tester or calculated from the correlation, and the angle of internal friction of the material. The predicted shift in the yield loci due to different moisture contents compare well with the measured shift in the yield loci of glass beads, crushed limestone, super D catalyst and Leslie coal. Measurement of the void fraction during the shear testing was critical to obtain the correct tensile strength theoretically or experimentally.

  20. Wet deposition and atmospheric mercury monitoring in Sisal, Yucatán, México, as part of the Global Mercury Observation System (GMOS) Part 1 - Report of 2013 Results

    OpenAIRE

    SENA Fabrizio; UMLAUF Gunther; ALONSO RUIZ AGUSTIN; RAMÍREZ ISLAS Martha; VELASCO Juan Antonio; ARCEGA CABRERA Flor; OCEGUERA VARGAS Ismael

    2015-01-01

    In order to investigate the occurrence and tends of mercury in ambient air and precipitation worldwide, the European Commission supported the creation of the Global Mercury Observation System (GMOS), a 5-year project, from 2011 to 2015. GMOS combines monitoring ground stations in different parts of the world, measurements in the Pacific Ocean, Atlantic and Mediterranean Sea, and airborne measurements. GMOS aims providing a temporal and spatial distribution of mercury levels in ambient air ...

  1. Wetting in Color

    OpenAIRE

    Burgess, Ian Bruce

    2012-01-01

    Colorimetric litmus tests such as pH paper have enjoyed wide commercial success due to their inexpensive production and exceptional ease of use. However, expansion of colorimetry to new sensing paradigms is challenging because macroscopic color changes are seldom coupled to arbitrary differences in the physical/chemical properties of a system. In this thesis I present in detail the development of Wetting in Color Technology, focusing primarily on its application as an inexpensive and highly...

  2. Letting Wet Spots be Wet: Restoring Natural Bioreactors in the Dissected Glacial Landscape

    Science.gov (United States)

    Schilling, Keith E.; McLellan, Eileen; Bettis, E. Arthur

    2013-12-01

    In this paper, we argue that there is tremendous potential for nitrate-N reductions to occur throughout the Corn Belt region of the USA if we simply let naturally occurring wet spots on the landscape be wet. Geologic and hydrologic data gathered in the Walnut Creek watershed located in south-central Iowa provides compelling evidence that substantial nutrient-processing capacity exists in this dissected glacial landscape. Self-similarity of stratigraphy, sedimentology and hydrology observed at all spatial scales in the watershed suggests that Holocene alluvial fill deposits provide a natural bioreactor for denitrification of upland groundwater nitrate-N; the occurrence of such deposits can be mapped to identify potential nitrogen sinks across the landscape. This approach to identifying potential nitrogen sinks is geology focused and extends potential locations for nutrient processing upstream into the headwater catchments of individual fields.

  3. Coffee-stain growth dynamics on dry and wet surfaces

    Science.gov (United States)

    Boulogne, François; Ingremeau, François; Stone, Howard A.

    2017-02-01

    The drying of a drop containing particles often results in the accumulation of the particles at the contact line. In this work, we investigate the drying of an aqueous colloidal drop surrounded by a hydrogel that is also evaporating. We combine theoretical and experimental studies to understand how the surrounding vapor concentration affects the particle deposit during the constant radius evaporation mode. In addition to the common case of evaporation on an otherwise dry surface, we show that in a configuration where liquid is evaporating from a flat surface around the drop, the singularity of the evaporative flux at the contact line is suppressed and the drop evaporation is homogeneous. For both conditions, we derive the velocity field and we establish the temporal evolution of the number of particles accumulated at the contact line. We predict the growth dynamics of the stain and the drying timescales. Thus, dry and wet conditions are compared with experimental results and we highlight that only the dynamics is modified by the evaporation conditions, not the final accumulation at the contact line.

  4. Wetting in Color

    Science.gov (United States)

    Burgess, Ian Bruce

    Colorimetric litmus tests such as pH paper have enjoyed wide commercial success due to their inexpensive production and exceptional ease of use. However, expansion of colorimetry to new sensing paradigms is challenging because macroscopic color changes are seldom coupled to arbitrary differences in the physical/chemical properties of a system. In this thesis I present in detail the development of Wetting in Color Technology, focusing primarily on its application as an inexpensive and highly selective colorimetric indicator for organic liquids. The technology exploits chemically-encoded inverse-opal photonic crystals to control the infiltration of fluids to liquid-specific spatial patterns, projecting minute differences in liquids' wettability to macroscopically distinct, easy-to-visualize structural color patterns. It is shown experimentally and corroborated with theoretical modeling using percolation theory that the high selectivity of wetting, upon-which the sensitivity of the indicator relies, is caused by the highly symmetric structure of our large-area, defect-free SiO2 inverse-opals. The regular structure also produces a bright iridescent color, which disappears when infiltrated with liquid - naturally coupling the optical and fluidic responses. Surface modification protocols are developed, requiring only silanization and selective oxidation, to facilitate the deterministic design of an indicator that differentiates a broad range of liquids. The resulting tunable, built-in horizontal and vertical chemistry gradients allow the wettability threshold to be tailored to specific liquids across a continuous range, and make the readout rely only on countable color differences. As wetting is a generic fluidic phenomenon, Wetting in Color technology could be suitable for applications in authentication or identification of unknown liquids across a broad range of industries. However, the generic nature of the response also ensures chemical non-specificity. It is shown

  5. Nutrient and mercury deposition and storage in an alpine snowpack of the Sierra Nevada, USA

    Science.gov (United States)

    Pearson, C.; Schumer, R.; Trustman, B. D.; Rittger, K.; Johnson, D. W.; Obrist, D.

    2015-06-01

    Biweekly snowpack core samples were collected at seven sites along two elevation gradients in the Tahoe Basin during two consecutive snow years to evaluate total wintertime snowpack accumulation of nutrients and pollutants in a high-elevation watershed of the Sierra Nevada. Additional sampling of wet deposition and detailed snow pit profiles were conducted the following year to compare wet deposition to snowpack storage and assess the vertical dynamics of snowpack nitrogen, phosphorus, and mercury. Results show that, on average, organic N comprised 48% of all snowpack N, while nitrate (NO3--N) and TAN (total ammonia nitrogen) made up 25 and 27%, respectively. Snowpack NO3--N concentrations were relatively uniform across sampling sites over the sampling seasons and showed little difference between seasonal wet deposition and integrated snow pit concentrations. These patterns are in agreement with previous studies that identify wet deposition as the dominant source of wintertime NO3--N deposition. However, vertical snow pit profiles showed highly variable concentrations of NO3--N within the snowpack indicative of additional deposition and in-snowpack dynamics. Unlike NO3--N, snowpack TAN doubled towards the end of winter, which we attribute to a strong dry deposition component which was particularly pronounced in late winter and spring. Organic N concentrations in the snowpack were highly variable (from 35 to 70%) and showed no clear temporal, spatial, or vertical trends throughout the season. Integrated snowpack organic N concentrations were up to 2.5 times higher than seasonal wet deposition, likely due to microbial immobilization of inorganic N as evident by coinciding increases in organic N and decreases in inorganic N in deeper, aged snow. Spatial and temporal deposition patterns of snowpack P were consistent with particulate-bound dry deposition inputs and strong impacts from in-basin sources causing up to 6 times greater enrichment at urban locations compared

  6. Multi-Constituent Simulation of Thrombus Deposition

    Science.gov (United States)

    Wu, Wei-Tao; Jamiolkowski, Megan A.; Wagner, William R.; Aubry, Nadine; Massoudi, Mehrdad; Antaki, James F.

    2017-02-01

    In this paper, we present a spatio-temporal mathematical model for simulating the formation and growth of a thrombus. Blood is treated as a multi-constituent mixture comprised of a linear fluid phase and a thrombus (solid) phase. The transport and reactions of 10 chemical and biological species are incorporated using a system of coupled convection-reaction-diffusion (CRD) equations to represent three processes in thrombus formation: initiation, propagation and stabilization. Computational fluid dynamic (CFD) simulations using the libraries of OpenFOAM were performed for two illustrative benchmark problems: in vivo thrombus growth in an injured blood vessel and in vitro thrombus deposition in micro-channels (1.5 mm × 1.6 mm × 0.1 mm) with small crevices (125 μm × 75 μm and 125 μm × 137 μm). For both problems, the simulated thrombus deposition agreed very well with experimental observations, both spatially and temporally. Based on the success with these two benchmark problems, which have very different flow conditions and biological environments, we believe that the current model will provide useful insight into the genesis of thrombosis in blood-wetted devices, and provide a tool for the design of less thrombogenic devices.

  7. PREFACE: Wetting: introductory note

    Science.gov (United States)

    Herminghaus, S.

    2005-03-01

    The discovery of wetting as a topic of physical science dates back two hundred years, to one of the many achievements of the eminent British scholar Thomas Young. He suggested a simple equation relating the contact angle between a liquid surface and a solid substrate to the interfacial tensions involved [1], γlg cos θ = γsg - γsl (1) In modern terms, γ denotes the excess free energy per unit area of the interface indicated by its indices, with l, g and s corresponding to the liquid, gas and solid, respectively [2]. After that, wetting seems to have been largely ignored by physicists for a long time. The discovery by Gabriel Lippmann that θ may be tuned over a wide range by electrochemical means [3], and some important papers about modifications of equation~(1) due to substrate inhomogeneities [4,5] are among the rare exceptions. This changed completely during the seventies, when condensed matter physics had become enthusiastic about critical phenomena, and was vividly inspired by the development of the renormalization group by Kenneth Wilson [6]. This had solved the long standing problem of how to treat fluctuations, and to understand the universal values of bulk critical exponents. By inspection of the critical exponents of the quantities involved in equation~(1), John W Cahn discovered what he called critical point wetting: for any liquid, there should be a well-defined transition to complete wetting (i.e., θ = 0) as the critical point of the liquid is approached along the coexistence curve [7]. His paper inspired an enormous amount of further work, and may be legitimately viewed as the entrance of wetting into the realm of modern physics. Most of the publications directly following Cahn's work were theoretical papers which elaborated on wetting in relation to critical phenomena. A vast amount of interesting, and in part quite unexpected, ramifications were discovered, such as the breakdown of universality in thin film systems [8]. Simultaneously, a number

  8. Wet steam wetness measurement in a 10 MW steam turbine

    Directory of Open Access Journals (Sweden)

    Kolovratník Michal

    2014-03-01

    Full Text Available The aim of this paper is to introduce a new design of the extinction probes developed for wet steam wetness measurement in steam turbines. This new generation of small sized extinction probes was developed at CTU in Prague. A data processing technique is presented together with yielded examples of the wetness distribution along the last blade of a 10MW steam turbine. The experimental measurement was done in cooperation with Doosan Škoda Power s.r.o.

  9. Temporal evolution of the giant Salobo IOCG deposit, Carajás Province (Brazil): constraints from paragenesis of hydrothermal alteration and U-Pb geochronology

    Science.gov (United States)

    deMelo, Gustavo H. C.; Monteiro, Lena V. S.; Xavier, Roberto P.; Moreto, Carolina P. N.; Santiago, Erika S. B.; Dufrane, S. Andrew; Aires, Benevides; Santos, Antonio F. F.

    2017-06-01

    The giant Salobo copper-gold deposit is located in the Carajás Province, Amazon Craton. Detailed drill core description, petrographical studies, and U-Pb SHRIMP IIe and LA-ICP-MS geochronology unravel its evolution regarding the host rocks, hydrothermal alteration and mineralization. Within the Cinzento Shear Zone, the deposit is hosted by orthogneisses of the Mesoarchean Xingu Complex (2950 ± 25 and 2857 ± 6.7 Ma) and of the Neoarchean Igarapé Gelado suite (2763 ± 4.4 Ma), which are crosscut by the Old Salobo granite. Remnants of the Igarapé Salobo metavolcanic-sedimentary sequence are represented by a quartz mylonite with detrital zircon populations (ca. 3.1-3.0, 2.95, 2.86, and 2.74 Ga). High-temperature calcic-sodic hydrothermal alteration (hastingsite-actinolite) was followed by silicification, iron-enrichment (almandine-grunerite-magnetite), tourmaline formation, potassic alteration with biotite, copper-gold ore formation, and later Fe-rich hydrated silicate alteration. Myrmekitic bornite-chalcocite and magnetite comprise the bulk of copper-gold ore. All these alteration assemblages have been overprinted by post-ore hematite-bearing potassic and propylitic alteration, which is also recognized in the Old Salobo granite. In the central zone of the deposit the mylonitized Igarapé Gelado suite rocks yield an age of 2701 ± 30 Ma. Zircon ages of 2547 ± 5.3 and 2535 ± 8.4 Ma were obtained for the Old Salobo granite and for the high-grade copper ore, respectively. A U-Pb LA-ICP-MS monazite age (2452 ± 14 Ma) from the copper-gold ore indicates hydrothermal activity and overprinting in the Siderian. Therefore, a protracted tectono-thermal event due to the reactivation of the Cinzento Shear Zone is proposed for the evolution of the Salobo deposit.

  10. Wetting dynamics beneath fluid drops impacting on hot surfaces

    Science.gov (United States)

    Harth, Kirsten; van Limbeek, Michiel A. J.; Shirota, Minori; Sun, Chao; Lohse, Detlef

    Fluid droplets encountering a phase transition when they impact a target surface are involved in many applications, e.g., spray cooling or painting / coating, ink-jet and 3D printing, soldering, firefighting using sprinklers. Drop impact on hot plates is an emerging topic, involving a complex interplay of hydrodynamics, heat flux and the occurring phase transition, involving large spatial and temporal gradients. Whether and to what extent droplets touch the surface is of immense importance for the overall heat transfer. High-speed total internal reflection imaging allows us to discriminate wetted and vapor-covered regions of the substrate. We study the transient wetting behaviour of the plate by varying the latent heat of the droplet. The characteristic cooling time of the plate is not solely determined by the plate properties. In addition to current literature, we show that in those cases the wetting pattern is both spatially and temporally inhomogeneous.

  11. Reactive nitrogen deposition to South East Asian rainforest

    Science.gov (United States)

    di Marco, Chiara F.; Phillips, Gavin J.; Thomas, Rick; Tang, Sim; Nemitz, Eiko; Sutton, Mark A.; Fowler, David; Lim, Sei F.

    2010-05-01

    The supply of reactive nitrogen (N) to global terrestrial ecosystems has doubled since the 1960s as a consequence of human activities, such as fertilizer application and production of nitrogen oxides by fossil-fuel burning. The deposition of atmospheric N species constitutes a major nutrient input to the biosphere. Tropical forests have been undergoing a radical land use change by increasing cultivation of sugar cane and oil palms and the remaining forests are increasingly affected by anthropogenic activities. Yet, quantifications of atmospheric nitrogen deposition to tropical forests, and nitrogen cycling under near-pristine and polluted conditions are rare. The OP3 project ("Oxidant and Particle Photochemical Processes above a Southeast Asian Tropical Rainforest") was conceived to study how emissions of reactive trace gases from a tropical rain forest mediate the regional scale production and processing of oxidants and particles, and to better understand the impact of these processes on local, regional and global scale atmospheric composition, chemistry and climate. As part of this study we have measured reactive, nitrogen containing trace gas (ammonia, nitric acid) and the associated aerosol components (ammonium, nitrate) at monthly time resolution using a simple filter / denuder for 16 months. These measurements were made at the Bukit Atur Global Atmospheric Watch tower near Danum Valley in the Malaysian state of Sabah, Borneo. In addition, the same compounds were measured at hourly time-resolution during an intensive measurement period, with a combination of a wet-chemistry system based on denuders and steam jet aerosol collectors and an aerosol mass spectrometer (HR-ToF-AMS), providing additional information on the temporal controls. During this period, concentrations and fluxes of NO, NO2 and N2O were also measured. The measurements are used for inferential dry deposition modelling and combined with wet deposition data from the South East Asian Acid

  12. Wet-aerosol leakage through simulated containment leak paths

    Energy Technology Data Exchange (ETDEWEB)

    Sutradhar, S.C. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

    2007-07-01

    Some types of postulated accidents in a nuclear reactor can result in the formation of radioactive wet aerosols in containment and their subsequent release into the environment. Wet-aerosol leakage was investigated using simulated leak paths for isolation damper valves and airlock door seals. Leakage was calculated from measured uranine concentrations deposited on high-quality filters positioned downstream of the simulated leak paths. Test results indicated that a small fraction of wet aerosols leaked through the simulated isolation damper valves, whereas a large fraction leaked through the simulated airlock door seals. Data on wet-aerosol leakage through containment leak paths are needed to develop and validate models in safety analysis codes. (author)

  13. Atmospheric Deposition of Phosphorus to the Everglades: Concepts, Constraints, and Published Deposition Rates for Ecosystem Management

    Directory of Open Access Journals (Sweden)

    Garth W. Redfield

    2002-01-01

    Full Text Available This paper summarizes concepts underlying the atmospheric input of phosphorus (P to ecosystems, published rates of P deposition, measurement methods, and approaches to future monitoring and research. P conveyed through the atmosphere can be a significant nutrient source for some freshwater and marine ecosystems. Particle sources and sinks at the land-air interface produce variation in P deposition from the atmosphere across temporal and spatial scales. Natural plant canopies can affect deposition rates by changing the physical environment and surface area for particle deposition. Land-use patterns can alter P deposition rates by changing particle concentrations in the atmosphere. The vast majority of P in dry atmospheric deposition is conveyed by coarse (2.5 to 10 μm and giant (10 to 100 μm particles, and yet these size fractions represent a challenge for long-term atmospheric monitoring in the absence of accepted methods for routine sampling. Most information on P deposition is from bulk precipitation collectors and wet/dry bucket sampling, both with questionable precision and accuracy. Most published annual rates of P deposition are gross estimates derived from bulk precipitation sampling in locations around the globe and range from about 5 to well over 100 mg P m–2 year–1, although most inland ecosystems receive between 20 and 80 mg P m–2 year–1. Rates below 30 mg P m–2 year–1 are found in remote areas and near coastlines. Intermediate rates of 30 to 50 mg P m–2 year–1 are associated with forests or mixed land use, and rates of 50 to 100 mg P m–2 year–1 or more are often recorded from urban or agricultural settings. Comparison with other methods suggests that these bulk precipitation estimates provide crude boundaries around actual P deposition rates for various land uses. However, data screening cannot remove all positive bias caused by contamination of bucket or bulk collectors. As a consequence, continued sampling

  14. Factors influencing temporal changes in chemical composition of biogenic deposits in the middle Tążyna River Valley (Kuyavian Lakeland, central Poland

    Directory of Open Access Journals (Sweden)

    Okupny Daniel

    2016-06-01

    Full Text Available The present paper discusses the influence of geochemical properties on biogenic deposits in the Wilkostowo mire near Toruń, central Poland. The analysed core has allowed the documentation of environmental changes between the older part of the Atlantic Period and the present day (probably interrupted at the turn of the Meso- and Neoholocene. In order to reconstruct the main stages in the sedimentation of biogenic deposits, we have used stratigraphic variability of selected litho-geochemical elements (organic matter, calcium carbonate, biogenic and terrigenous silica, macro- and micro-elements: Na, K, Mg, Ca, Fe, Mn, Cu, Zn, Pb, Cr and Ni. The main litho-geochemical component is CaCO3; its content ranges from 4.1 per cent to 92 per cent. The variability of CaCO3 content reflects mainly changes in hydrological and geomorphological conditions within the catchment area. The effects of prehistoric anthropogenic activities in the catchment of the River Tążyna, e.g., the use of saline water for economic purposes, are recorded in a change from calcareous gyttja into detritus-calcareous gyttja sedimentation and an increased content of lithophilous elements (Na, K, Mg and Ni in the sediments. Principal component analysis (PCA has enabled the distinction the most important factors that affected the chemical composition of sediments at the Wilkostowo site, i.e., mechanical and chemical denudation processes in the catchment, changes in redox conditions, bioaccumulation of selected elements and human activity. Sediments of the Wilkostowo mire are located in the direct vicinity of an archaeological site, where traces of intensive settlement dating back to the Neolithic have been documented. The settlement phase is recorded both in lithology and geochemical properties of biogenic deposits which fill the reservoir formed at the bottom of the Parchania Canal Valley.

  15. Nitrogen Deposition onto the United States and Western Europe

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains data for wet and dry nitrogen-species deposition for the United States and Western Europe. Deposition data were acquired directly from...

  16. Regional estimation of pollutant gas dry deposition in the UK: model description, sensitivity analyses and outputs

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R.I.; Fowler, D.; Sutton, M.A.; Flechard, C.; Coyle, M. [Institute of Terrestrial Ecology, Penicuik (United Kingdom). Edinburgh Research Station

    2000-07-01

    A ''big-leaf'' resistance analogy model for dry deposition of sulphur dioxide, nitrogen dioxide, ammonia and nitric acid is described with a stomatal compensation point included to allow bidirectional exchange of ammonia. The model derivation is constrained by measurement data and it is parameterized for UK conditions. Monthly average dry deposition estimates are provided at the 5 km x 5 km spatial scale. The model uses data available nationally at the appropriate spatial and temporal scales, such as gas concentration, land use, wind speed, temperature, rainfall and vapour pressure. A method is presented to overcome the lack of suitable solar radiation data. The effect of uncertainty in model inputs and in model parameterization is explored using sensitivity analyses. SO{sub 2} deposition is sensitive to variation in gas concentration, wind speed and wet surface uptake parameters. NO{sub 2} deposition is sensitive to parameters and inputs regulating stomatal behaviour, including solar radiation and temperature, as well as to gas concentration. The use of monthly or annual average NO{sub 2} concentrations may underestimate deposition substantially in some areas. HNO{sub 3} dry deposition is sensitive to wind speed and concentration. NH{sub 3} dry deposition to moorland and forest land uses, where the majority of deposition occurs, is sensitive to concentration, wind speed and choice of canopy resistance parameters. For arable and grassland areas, with both deposition and emission of NH{sub 3}, the model is sensitive to all the model inputs and parameter choices. A full uncertainty analysis requires further work on the reliability of input variables and model parameter choices but these results quantitatively focus on the important areas of the model for each gas. Estimated dry deposition to the UK (excluding Northern Ireland) of SO{sub 2} is 135 Gg S yr{sup -1} for 1996, for NH{sub 3} is 97 Gg N yr{sup -1}, for NO{sub 2} is 26 Gg N yr{sup -1} and

  17. Spatial and temporal small-scale variability of nitrogen mobilization in a forest ecosystem with high N deposition in NW-Germany

    Energy Technology Data Exchange (ETDEWEB)

    Lorz, Carsten, E-mail: carsten.lorz@tu-dresden.d [Institute of Soil Science and Site Ecology, Dresden University of Technology, Pienner Str. 19, 01737 Tharandt Germany (Germany); Eissner, Christel, E-mail: ceissner@rz.uni-leipzig.d [Department of Geography, University of Leipzig, Johannisallee 19, 04103 Leipzig (Germany); Lethmate, Juergen, E-mail: lethmat@uni-muenster.d [Department of Didactics in Geography, Westfaelische Wilhelms-Universitaet Muenster, Robert-Koch Str. 26, 48149 Muenster (Germany); Schneider, Birgit, E-mail: bschneid@rz.uni-leipzig.d [Department of Geography, University of Leipzig, Johannisallee 19, 04103 Leipzig (Germany)

    2010-02-15

    For conifer stands in NW-Germany with high DIN load (23-35 kg N ha{sup -1} a{sup -1}) and a long history of nitrogen export the risk of N mobilization were investigated. Ammonium is the most mobilized N species, pointing towards either conditions not favoring nitrification or, more likely - under the dominant aerobic conditions - a very high amount of ammonium in the forest floor. Independence of net nitrification and net ammonification from each other indicates the existence of two separate systems. The nitrifying system depends very much on biotic conditions - as a function of energy and moisture - and seems not to be directly related to N deposition. In contrast, for the ammonification system (Oe horizon) a correlation with the sum of ammonium deposition three months prior to sampling was found. However, the role of disturbance, i.e. nitrogen export, during the last centuries and the role of recovery of the N balance during the last 150 years is still not clear. - For conifer stands in NW-Germany with a high DIN load and a history of nitrogen export we found - independent from tree species - ammonium to be the most mobilized N species.

  18. Temporal evolution of urate crystal deposition over articular cartilage after successful urate-lowering therapy in patients with gout: An ultrasonographic perspective.

    Science.gov (United States)

    Das, Shyamashis; Goswami, Rudra Prosad; Ghosh, Alakendu; Ghosh, Parasar; Lahiri, Debasish; Basu, Kaushik

    2017-05-01

    To detect evolution of ultrasonographic signs of deposition of monosodium urate crystals (MSUC) in gouty joints by serial ultrasonography after initiation of urate-lowering therapy (ULT). Adult gout patients were examined by serial ultrasonography after initiation of ULT with target serum uric acid (SUA) gout with mean age of 50 ± 11 years, median disease duration of 48 months and baseline mean SUA level of 8.8 ± 1.5 mg/dL were recruited. Ultrasonographic evidence of MSUC deposition was detected in 89.74% of first metatarsophalangeal (MTP) joints and 27.63% of knee joints. Double contour sign (DCS), tophi, and hyperechoic spots (HES) were detected in 77.63%, 43.42%, and 19.74% of first MTPs, respectively. SUA level normalizes and plateaus after fourth month of follow-up. DCS thickness reduced significantly throughout the follow-up period. Overall, 86.25% DCS and 100% HES disappeared with median time of 6 months and 5.7 months, respectively. SUA normalization was the only significant predictor of DCS disappearance. Serial ultrasonographic determination of DCS, tophi, or HES during hypouricemic therapy is a noninvasive, effective method to detect the lowering of burden of urate load in gouty joints.

  19. ROE Total Nitrogen Deposition 1989-1991

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset identifies the amount of wet, dry, and total deposition of nitrogen in kilograms per hectare from 1989 to 1991 at a set of point locations across the...

  20. ROE Total Nitrogen Deposition 2011-2013

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset identifies the amount of wet, dry, and total deposition of nitrogen in kilograms per hectare from 2011 to 2013 at a set of point locations across the...

  1. ROE Total Sulfur Deposition 1989-1991

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset identifies the amount of wet, dry, and total deposition of sulfur in kilograms per hectare from 1989 to 1991 at a set of point locations across the...

  2. Forced wetting and hydrodynamic assist

    Science.gov (United States)

    Blake, Terence D.; Fernandez-Toledano, Juan-Carlos; Doyen, Guillaume; De Coninck, Joël

    2015-11-01

    Wetting is a prerequisite for coating a uniform layer of liquid onto a solid. Wetting failure and air entrainment set the ultimate limit to coating speed. It is well known in the coating art that this limit can be postponed by manipulating the coating flow to generate what has been termed "hydrodynamic assist," but the underlying mechanism is unclear. Experiments have shown that the conditions that postpone air entrainment also reduce the apparent dynamic contact angle, suggesting a direct link, but how the flow might affect the contact angle remains to be established. Here, we use molecular dynamics to compare the outcome of steady forced wetting with previous results for the spontaneous spreading of liquid drops and apply the molecular-kinetic theory of dynamic wetting to rationalize our findings and place them on a quantitative footing. The forced wetting simulations reveal significant slip at the solid-liquid interface and details of the flow immediately adjacent to the moving contact line. Our results confirm that the local, microscopic contact angle is dependent not simply only on the velocity of wetting but also on the nature of the flow that drives it. In particular, they support an earlier suggestion that during forced wetting, an intense shear stress in the vicinity of the contact line can assist surface tension forces in promoting dynamic wetting, thus reducing the velocity-dependence of the contact angle. Hydrodynamic assist then appears as a natural consequence of wetting that emerges when the contact line is driven by a strong and highly confined flow. Our theoretical approach also provides a self-consistent model of molecular slip at the solid-liquid interface that enables its magnitude to be estimated from dynamic contact angle measurements. In addition, the model predicts how hydrodynamic assist and slip may be influenced by liquid viscosity and solid-liquid interactions.

  3. Modeling the impact of bay breeze circulations on nitrogen deposition

    Science.gov (United States)

    Loughner, C. P.; Tzortziou, M.; Pickering, K. E.; Duffy, M.; Satam, C.

    2012-12-01

    Atmospheric gases and aerosols are deposited into watersheds and estuarine waters contributing to water quality degradation and affecting estuarine and coastal biogeochemical processes. Pollution that is deposited onto land can be transported into storm drains, groundwater, streams, and rivers where it is eventually transported into near-shore waters. Air quality models, which simulate the chemical transformation, atmospheric transport, and deposition of pollutants onto land and surface waters, can play an integral role in forecasting water quality, preparing water quality regulations and providing information on the sources of nutrients and pollutants for advanced estuarine biogeochemical models. Previous studies have found that Chesapeake Bay breezes cause localized areas of high air pollution concentrations and that model simulations with horizontal resolutions coarser than about 5 km are not able to capture bay breeze circulations. Here, we investigate the importance of capturing bay breeze circulations with high resolution model simulations (horizontal resolution of 1.33 km) to accurately simulate the spatial and temporal variability of nitrogen deposition into the Chesapeake Bay watershed. Nitrogen deposition into the watershed from air quality model simulations are compared with observed wet deposition and estimated dry deposition rates from the National Acid Deposition Program (NADP) and the Clean Air Status and Trends Network (CASTNET), respectively. The model simulation is conducted for the months of June and July 2011. Two concurrent air and water quality field campaigns, DISCOVER-AQ (Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality) and GeoCAPE-CBODAQ (Geostationary Coastal and Air Pollution Events-Chesapeake Bay Oceanographic Campaign with DISCOVER-AQ), were conducted in July 2011, and data obtained from these field experiments are used to evaluate the model simulations.

  4. Variability of mineral dust deposition in the western Mediterranean basin and south-east of France

    Science.gov (United States)

    Vincent, Julie; Laurent, Benoit; Losno, Rémi; Bon Nguyen, Elisabeth; Roullet, Pierre; Sauvage, Stéphane; Chevaillier, Servanne; Coddeville, Patrice; Ouboulmane, Noura; di Sarra, Alcide Giorgio; Tovar-Sánchez, Antonio; Sferlazzo, Damiano; Massanet, Ana; Triquet, Sylvain; Morales Baquero, Rafael; Fornier, Michel; Coursier, Cyril; Desboeufs, Karine; Dulac, François; Bergametti, Gilles

    2016-07-01

    Previous studies have provided some insight into the Saharan dust deposition at a few specific locations from observations over long time periods or intensive field campaigns. However, no assessment of the dust deposition temporal variability in connection with its regional spatial distribution has been achieved so far from network observations over more than 1 year. To investigate dust deposition dynamics at the regional scale, five automatic deposition collectors named CARAGA (Collecteur Automatique de Retombées Atmosphériques insolubles à Grande Autonomie in French) have been deployed in the western Mediterranean region during 1 to 3 years depending on the station. The sites include, from south to north, Lampedusa, Majorca, Corsica, Frioul and Le Casset (southern French Alps). Deposition measurements are performed on a common weekly period at the five sites. The mean dust deposition fluxes are higher close to the northern African coasts and decrease following a south-north gradient, with values from 7.4 g m-2 year-1 in Lampedusa (35°31' N, 12°37' E) to 1 g m-2 year-1 in Le Casset (44°59' N, 6°28' E). The maximum deposition flux recorded is of 3.2 g m-2 wk-1 in Majorca with only two other events showing more than 1 g m-2 wk-1 in Lampedusa, and a maximum of 0.5 g m-2 wk-1 in Corsica. The maximum value of 2.1 g m-2 year-1 observed in Corsica in 2013 is much lower than existing records in the area over the 3 previous decades (11-14 g m-2 year-1). From the 537 available samples, 98 major Saharan dust deposition events have been identified in the records between 2011 and 2013. Complementary observations provided by both satellite and air mass trajectories are used to identify the dust provenance areas and the transport pathways from the Sahara to the stations for the studied period. Despite the large size of African dust plumes detected by satellites, more than 80 % of the major dust deposition events are recorded at only one station, suggesting that the dust

  5. [Effect of dust deposition collection methods on collection efficiency].

    Science.gov (United States)

    Zhang, Zheng-Cai; Dong, Zhi-Bao

    2013-02-01

    There are lots of dust deposition collection methods on dust deposition, but there is no standard field observation method. At present, researchers have studied dust deposition using different methods in this issue, but due to the different observation method and collection efficiency, the research results are incomparable. The efficiency of the standard dust deposition gauge including dry, wet, net, net and glass ball and slowing speed methods was studied in the Tengger Desert. The amount of the dry method collected material was only about 5% to 62% of the wet method, the net method was only about 43% to 89% of the wet method, the net and glass ball method was only about 40% to 80% of the wet method. Wind speed obviously affected the dust deposition efficiency in all observation methods, the dust deposition efficiency decreased with increasing wind speed when the wind speed was smaller than 2.5 m.s-1, but the dust deposition efficiency had no clear trend with wind speed when the wind speed was larger than 2.5 m.s-1. The particle size of collected material by wet method was the smallest, followed by the slowing speed method, the net and glass ball method, the wet method and the dry method. There are relationships between the averaged wind speed, the averaged larger than 5 m.s-1 wind speed and the amount of dust deposition collected by the wet and the slowing speed methods, which can be expressed as exponential function. There are also linear relationships between the amount of collected material by the wet and dry, net, net and glass ball and slowing speed methods. The wet method is the best dust deposition collecting method, followed by the slow wind speed method. Therefore, in the arid and semi-arid regions, the slowing wind speed method can be used to replace the wet method to collect dust deposition.

  6. Examining Wetting and Dewetting Processes in Thin-films on Crystalline Substrates at the Nanoscale

    Science.gov (United States)

    Hihath, Sahar

    Controlling the wetting and dewetting of ultra-thin films on solid substrates is important for a variety of technological and fundamental research applications. These applications include film deposition for semiconductor manufacturing, the growth of nanowires through nanoparticle-based catalysis sites, to making ordered arrays of nanoscale particles for electronic and optical devices. However, despite the importance of these processes, the underlying mechanisms by which a film wets a surface or dewets from it is still often unclear and widely debated. In this dissertation we examine wetting and dewetting processes in three materials systems that are relevant for device applications with the ultimate goal of understanding what mechanisms drive the wetting (or dewetting) process in each case. First, we examine the formation of wetting layers between nanoparticle films and highly conductive GaAs substrates for spintronic applications. In this case, the formation of a wetting layer is important for nanoparticle adhesion on the substrate surface. Wetting layers can be made by annealing these systems, which causes elemental diffusion from nanoparticles into the substrate, thereby adhesion between the nanoparticles and the substrate. Here we investigate the feasibility of forming a wetting layer underneath nanoparticles post-annealing in a system of Fe3O4 nanoparticles on a (100) GaAs substrate by studying the interface structure and composition via Transmission Electron Microscopy (TEM), Scanning Transmission Electron Microscopy (STEM), Electron Energy Loss Spectroscopy (EELS) and Energy Dispersive X-ray Spectroscopy (EDXS). Electron Energy-Loss fine structures of the Fe-L 3,2 and O-K absorption edges were quantitatively analyzed to gain insight about the compositional gradient of the interface between the nanoparticles and the GaAs substrate. Additionally, real-space density functional theory calculations of the dynamical form factor was performed to confirm the

  7. Total Nitrogen Deposition (wet+dry) from the Atmosphere

    Data.gov (United States)

    U.S. Environmental Protection Agency — Oxides of Nitrogen are emitted primarily as by-products of combustion. Sources include power plants, industrial boilers, and automobiles. In addition, agricultural...

  8. Total Sulfur Deposition (wet+dry) from the Atmosphere

    Data.gov (United States)

    U.S. Environmental Protection Agency — Sulfur Dioxide (SO2) is emitted primarily as a by-product of coal combustion from power plants. Sulfur Dioxide reacts in the atmosphere to form other chemical such...

  9. Lichen-based critical loads for atmospheric nitrogen deposition in Western Oregon and Washington forests, USA

    Science.gov (United States)

    Linda H. Geiser; Sarah E. Jovan; Doug A. Glavich; Matthew K. Porter

    2010-01-01

    Critical loads (CLs) define maximum atmospheric deposition levels apparently preventative of ecosystem harm. We present first nitrogen CLs for northwestern North America's maritime forests. Using multiple linear regression, we related epiphytic-macrolichen community composition to: 1) wet deposition from the National Atmospheric Deposition Program, 2) wet, dry,...

  10. Remote sensing and GIS analysis for mapping spatio-temporal changes of erosion and deposition of two Mediterranean river deltas: The case of the Axios and Aliakmonas rivers, Greece

    Science.gov (United States)

    Petropoulos, George P.; Kalivas, Dionissios P.; Griffiths, Hywel M.; Dimou, Paraskevi P.

    2015-03-01

    Wetlands are among Earth's most dynamic, diverse and varied habitats as the balance between land and water surfaces provide shelter to a unique mixture of plant and animal species. This study explores the changes in two Mediterranean wetland delta environments formed by the Axios and Aliakmonas rivers located in Greece, over a 25-year period (1984-2009). Direct photo-interpretation of four Landsat TM images acquired during the study period was performed. Furthermore, a sophisticated, semi-automatic image classification method based on support vector machines (SVMs) was developed to streamline the mapping process. Deposition and erosion magnitudes at different temporal scales during the study period were quantified using both approaches based on coastline surface area changes. Analysis using both methods was conducted in a geographical information systems (GIS) environment. Direct photo-interpretation, which formed our reference dataset, showed noticeable changes in the coastline deltas of both study areas, with erosion occurring mostly in the earlier periods (1990-2003) in both river deltas followed by deposition in more recent years (2003-2009), but at different magnitudes. Spatial patterns of coastline changes predicted from the SVMs showed similar trends. In absolute terms SVMs predictions of sediment erosion and deposition in the studied area were different in the order of 5-20% in comparison to photo-interpretation, evidencing the potential capability of this method in coastline changes monitoring. One of the main contributions of our work lies to the use of the SVMs classifier in coastal mapping of changes, since to our knowledge use of this technique has been under-explored in this application domain. Furthermore, this study provides important contribution to the understanding of Mediterranean river delta dynamics and their behaviours, and corroborates the usefulness of EO technology and GIS as an effective tool in policy decision making and successful

  11. Wetting of Water on Graphene

    KAUST Repository

    Bera, Bijoyendra

    2016-11-28

    The wetting properties of graphene have proven controversial and difficult to assess. The presence of a graphene layer on top of a substrate does not significantly change the wetting properties of the solid substrate, suggesting that a single graphene layer does not affect the adhesion between the wetting phase and the substrate. However, wetting experiments of water on graphene show contact angles that imply a large amount of adhesion. Here, we investigate the wetting of graphene by measuring the mass of water vapor adsorbing to graphene flakes of different thickness at different relative humidities. Our experiments unambiguously show that the thinnest of graphene flakes do not adsorb water, from which it follows that the contact angle of water on these flakes is ~180o. Thicker flakes of graphene nanopowder, on the other hand, do adsorb water. A calculation of the van der Waals (vdW) interactions that dominate the adsorption in this system confirms that the adhesive interactions between a single atomic layer of graphene and water are so weak that graphene is superhydrophobic. The observations are confirmed in an independent experiment on graphene-coated water droplets that shows that it is impossible to make liquid \\'marbles\\' with molecularly thin graphene.

  12. Surface structure determines dynamic wetting

    Science.gov (United States)

    Shiomi, Junichiro; Wang, Jiayu; Do-Quang, Minh; Cannon, James; Yue, Feng; Suzuki, Yuji; Amberg, Gustav

    2014-11-01

    Dynamic wetting, the spontaneous spreading process after droplet contacts a solid surface, is important in various engineering processes, such as in printing, coating, and lubrication. In the recent years, experiments and numerical simulations have greatly progressed the understanding in the dynamic wetting particularly on ``flat'' substrates. To gain further insight into the governing physics of the dynamic wetting, we perform droplet-wetting experiments on microstructured surfaces, just a few micrometers in size, with complementary numerical simulations, and investigate the dependence of the spreading rate on the microstructure geometries and fluid properties. We reveal that the influence of microstructures can be quantified in terms of a line friction coefficient for the energy dissipation rate at the contact line, and that this can be described in a simple formula in terms of the geometrical parameters of the roughness and the line-friction coefficient of the planar surface. The systematic study is also of practical importance since structures and roughness are omnipresent and their influence on spreading rate would give us additional degrees of freedom to control the dynamic wetting. This work was financially supported in part by, the Japan Society for the Promotion of Science (J.W., J.C., and J.S) and Swedish Governmental Agency for Innovation Systems (M.D.-Q. and G.A.).

  13. Seasonal and Spatial Variations of Bulk Nitrogen Deposition and the Impacts on the Carbon Cycle in the Arid/Semiarid Grassland of Inner Mongolia, China.

    Science.gov (United States)

    Li, Xianglan; Shi, Huiqiu; Xu, Wenfang; Liu, Wei; Wang, Xiujun; Hou, Longyu; Feng, Fei; Yuan, Wenping; Li, Linghao; Xu, Hua

    2015-01-01

    Atmospheric nitrogen (N) deposition is an important component that affects the structure and function of different terrestrial ecosystem worldwide. However, much uncertainty still remains concerning the magnitude of N deposition on grassland ecosystem in China. To study the spatial and temporal patterns of bulk N deposition, the levels of N (NH4+-N and NO3--N) concentration in rainfall were measured at 12 sites across a 1200 km grassland transect in Inner Mongolia, China, and the respective N deposition rates were estimated. The inorganic N deposition rates ranged from 4.53 kg N ha-1 to 12.21 kg N ha-1 with a mean value of 8.07 kg N ha-1 during the entire growing season, decreasing steadily from the eastern to the western regions. Inorganic N deposition occurred mainly in July and August across meadow steppe, typical steppe, and desert steppe, which corresponded to the seasonal distribution of mean annual precipitation. A positive relationship was found between inorganic N deposition and mean annual precipitation (R2 = 0.54 ~ 0.72, P < 0.0001) across the grassland transect. Annual estimation of inorganic N deposition was 0.67 Pg yr-1 in Inner Mongolia, China based on the correlation between N deposition rates and precipitation. N deposition was an important factor controlling aboveground biomass and ecosystem respiration, but has no effect on root biomass and soil respiration. We must clarify that we used the bulk deposition samplers during the entire sampling process and estimated the dissolved NH4+-N and NO3--N deposition rates during the entire growing season. Long-term N deposition monitoring networks should be constructed to study the patterns of N deposition and its potential effect on grassland ecosystem, considering various N species, i.e., gaseous N, particle N, and wet N deposition.

  14. Seasonal and Spatial Variations of Bulk Nitrogen Deposition and the Impacts on the Carbon Cycle in the Arid/Semiarid Grassland of Inner Mongolia, China.

    Directory of Open Access Journals (Sweden)

    Xianglan Li

    Full Text Available Atmospheric nitrogen (N deposition is an important component that affects the structure and function of different terrestrial ecosystem worldwide. However, much uncertainty still remains concerning the magnitude of N deposition on grassland ecosystem in China. To study the spatial and temporal patterns of bulk N deposition, the levels of N (NH4+-N and NO3--N concentration in rainfall were measured at 12 sites across a 1200 km grassland transect in Inner Mongolia, China, and the respective N deposition rates were estimated. The inorganic N deposition rates ranged from 4.53 kg N ha-1 to 12.21 kg N ha-1 with a mean value of 8.07 kg N ha-1 during the entire growing season, decreasing steadily from the eastern to the western regions. Inorganic N deposition occurred mainly in July and August across meadow steppe, typical steppe, and desert steppe, which corresponded to the seasonal distribution of mean annual precipitation. A positive relationship was found between inorganic N deposition and mean annual precipitation (R2 = 0.54 ~ 0.72, P < 0.0001 across the grassland transect. Annual estimation of inorganic N deposition was 0.67 Pg yr-1 in Inner Mongolia, China based on the correlation between N deposition rates and precipitation. N deposition was an important factor controlling aboveground biomass and ecosystem respiration, but has no effect on root biomass and soil respiration. We must clarify that we used the bulk deposition samplers during the entire sampling process and estimated the dissolved NH4+-N and NO3--N deposition rates during the entire growing season. Long-term N deposition monitoring networks should be constructed to study the patterns of N deposition and its potential effect on grassland ecosystem, considering various N species, i.e., gaseous N, particle N, and wet N deposition.

  15. Ozone deposition to an oat crop ( Avena sativa L.) grown in open-top chambers and in the ambient air

    Science.gov (United States)

    Pleijel, H.; Wallin, G.; Karlsson, P. E.; Skarby, L.; Sellden, G.

    Fluxes and deposition velocities for ozone were determined for open-top chambers with and without an oat crop, and for the adjacent field, using a resistance analogue model and the aerodynamic wind-profile method, respectively. During a period when the canopy was green and the ambient wind speeds modest, the fluxes and deposition velocities were higher in the chamber with plants than in the field crop. The deposition to chamber walls and soil in the chamber only accounted for part of that difference. The deposition velocity for ozone to the crop was light-dependent both in the chamber with plants and in the ambient air. With increasing plant senescence, the deposition velocity declined and the light dependence disappeared. Fluctuations in deposition velocity superimposed on the overall declining trend followed the same temporal pattern in the chambers with and without plants. These fluctuations in deposition velocity may partly be explained by variations in surface wetness. Differences in boundary layer conductance between chamber and ambient, which under certain conditions may significantly influence the validity of the chamber as a test system, were observed.

  16. Properties of soils and tree wood tissue across a Lake States sulfate deposition gradient.

    Science.gov (United States)

    Lewis F. Ohmann; David F. Grigal

    1991-01-01

    Presents the soil and tree wood tissue properties (mostly chemical) of the plots that were remeasured and sampled for a study of the relation between forest condition and wet sulfate deposition along the Lake States acidic deposition gradient.

  17. Wet water glass production plant

    Directory of Open Access Journals (Sweden)

    Stanković Mirjana S.

    2003-01-01

    Full Text Available The IGPC Engineering Department designed basic projects for a wet hydrate dissolution plant, using technology developed in the IGPC laboratories. Several projects were completed: technological, machine, electrical, automation. On the basis of these projects, a production plant of a capacity of 75,000 t/y was manufactured, at "Zeolite Mira", Mira (VE, Italy, in 1997. and 1998, increasing detergent zeolite production, from 50,000 to 100,000 t/y. Several goals were realized by designing a wet hydrate dissolution plant. The main goal was increasing the detergent zeolite production. The technological cycle of NaOH was closed, and no effluents emitted, and there is no pollution (except for the filter cake. The wet water glass production process is fully automatized, and the product has uniform quality. The production process can be controlled manually, which is necessary during start - up, and repairs. By installing additional process equipment (centrifugal pumps and heat exchangers technological bottlenecks were overcome, and by adjusting the operation of autoclaves, and water glass filters and also by optimizing the capacities of process equipment.

  18. Different regimes of dynamic wetting

    Science.gov (United States)

    Gustav, Amberg; Wang, Jiayu; Do-Quang, Minh; Shiomi, Junichiro; Physiochemical fluid mechanics Team; Maruyama-Chiashi Laboratory Team

    2014-11-01

    Dynamic wetting, as observed when a droplet contacts a dry solid surface, is important in various engineering processes, such as printing, coating, and lubrication. Our overall aim is to investigate if and how the detailed properties of the solid surface influence the dynamics of wetting. Here we discuss how surface roughness influences the initial dynamic spreading of a partially wetting droplet by studying the spreading on a solid substrate patterned with microstructures just a few micrometers in size. This is complemented by matching numerical simulations. We present a parameter map, based on the properties of the liquid and the solid surface, which identifies qualitatively different spreading regimes, where the spreading speed is limited by either the liquid viscosity, the surface properties, or the liquid inertia. The peculiarities of the different spreading regimes are studied by detailed numerical simulations, in conjuction with experiments. This work was financially supported in part by, the Japan Society for the Promotion of Science (J.W. and J.S) and Swedish Governmental Agency for Innovation Systems (M.D.-Q. and G.A).

  19. Effect of dry deposition, washout and resuspension on radionuclide ratios after the Chernobyl accident.

    Science.gov (United States)

    Rosner, G; Hötzl, H; Winkler, R

    1990-01-01

    The temporal variations of radionuclide ratios in air and deposition samples collected simultaneously at Munich-Neuherberg (F.R.G.) after the Chernobyl accident have been studied. Until 8 May 1986, the radionuclides investigated were 99Mo, 103Ru, 106Ru, 110mAg, 125Sb, 129mTe, 132Te, 131I, 134Cs, 137Cs, 140Ba, 141Ce and 144Ce. After 8 May, 99Mo, 110mAg, 125Sb, and the Ce isotopes were below the detection limits. Considerable temporal variations of the above radionuclides, relative to 137Cs, were observed in air as well as in deposition. In air the temporal variations reflect the arrival of different parts of the reactor plume with different elemental composition. In deposition, the temporal patterns were quite different from those in air for a given radionuclide. This is explained by varying contributions of dry and wet deposition. Until 8 May, the washout ratios of the above radionuclides covered a range from 240 to 5600, with smaller variations for all radionuclides within one event (e.g. 460-910), and larger variations from one event to another (e.g. 460-3300 for 137Cs). The dry deposition velocity of 137Cs was found to be 0.27 cm s-1, similar to that of 110mAg, aerosol 131I and 140Ba (0.37, 0.13 and 0.15 cm s-1). Another group of radionuclides includes 103Ru, 106Ru, 125Sb, total 131I and 132Te with dry deposition velocities of 0.08, 0.10, 0.07, 0.03 and 0.08 cm s-1 and with temporal variations in deposition which are quite different from those of the first group. From 8 May to the end of June, the washout ratios increased to values between 1500 and 24,000, with the exception of iodine, which had considerably lower washout ratios of between 37 and 4400. These later effects are explained by resuspension and, in the case of iodine, by remobilization of gaseous species.

  20. Biomonitoring spatial and temporal impact of atmospheric dust from a cement industry

    Energy Technology Data Exchange (ETDEWEB)

    Branquinho, Cristina [Universidade de Lisboa, Faculdade de Ciencias, Centro de Ecologia e Biologia Vegetal, Campo Grande, Edificio C2, Piso 4, 1749-016 Lisbon (Portugal); Universidade Atlantica, Antiga Fabrica da Polvora de Barcarena, 2745-615 Barcarena (Portugal)], E-mail: cmbranquinho@fc.ul.pt; Gaio-Oliveira, Gisela; Augusto, Sofia; Pinho, Pedro; Maguas, Cristina; Correia, Otilia [Universidade de Lisboa, Faculdade de Ciencias, Centro de Ecologia e Biologia Vegetal, Campo Grande, Edificio C2, Piso 4, 1749-016 Lisbon (Portugal)

    2008-01-15

    The objective of this work was to evaluate the spatial and temporal impact of dust-pollution in the vicinity of a cement industry, located in an area with dry climate. The spatial impact integrated over time was evaluated from the concentrations of Ca, Fe and Mg in in-situ Xanthoria parietina. The temporal pattern was assessed through one-month transplants of the lichen Ramalina canariensis. Four potential sources of atmospheric dust were evaluated: the limestone-quarry; the unpaved roads, the deposit area and the cement mill. Calcium concentration in lichens was considered the best cement-dust indicator. Different types of dust (clinker and grinded-limestone-dust) resulted in different time-patterns of Ca accumulation, which was also related with the different influence that wet and dry periods have in the lichen accumulation process. The dust pollution was found to be deposited locally and dependent on: the nature of dust particles and the volume and frequency of precipitation. - Biomonitoring Spatial and Temporal dust emissions in dry climates.

  1. Differences between nipher and slter shielded rain gages at two Colorado deposition monitoring sites

    Science.gov (United States)

    Bigelow, David S.; Denning, A. Scott

    1990-01-01

    In the last decade the United States and Canada have made significant progress in establishing spatial ad temporal estimates of atmospheric deposition throughout North America. Fundamental to the wet-deposition portion of these estimates is the accurate and precise measurement of precipitation amount. Goodison and others (I-3) have reported on a new type of shielded snow gage known as the Canadian MSC Nipher shielded snow gage. Because this shielded snow gage has been shown to be superior to other precipitation gages for the estimation of snowfall amount, its design was adapted to the Universal Belfort precipitation gage (4), the dominant precipitation gage used at deposition monitoring sites in the United States. Favorable results taken from monitoring sites using this modified Nipher shielded snow gage (3-6) have prompted the U.S. Environmental Protection Agency and the Electric Power Research Institute to adopt the Nipher shielded Belfort gage as a standard piece of equipment in the Acid MODES and Operational Evaluation Network (OEN) monitoring programs and to propose that is be included as a standard snow gage in other North American deposition monitoring programs. This communication details preliminary results from two of nine NADP/NTN deposition monitoring sites selected by the Environmental Protection Agency to compare Nipher shielded Belfort precipitation gage volumes to volumes obtained from the standard Belfort gage used in the NADP/NTN monitoring program.

  2. Landfill Mining - Wet mechanical treatment of fine MSW with a wet jigger.

    Science.gov (United States)

    Wanka, Sebastian; Münnich, Kai; Fricke, Klaus

    2017-01-01

    The motives for landfill mining are various. In the last couple of years Enhanced Landfill Mining (ELFM) has become increasingly important in academic discourse and practical implementation. The main goal of ELFM is to recover as much material as possible from deposited municipal solid waste (MSW). In most of the projects carried out so far, the main focus has been set on coarse materials such as plastics, woods, papers and metals. These fractions can be separated easily by sieving in combination with magnetic separation. In these projects most of the fine materials, which might represent as much as 60-70% of the total mass of the landfill body, had to be deposited again. A further treatment aiming at reducing the masses of these fine materials, which are still a conglomerate of soil, calorific fractions, metals, minerals and residues, usually did not take place. One topic in the framework of the landfill mining project TÖNSLM, in addition to the separation of the calorific fraction and metals has been the treatment of fine materials with the goal to re-use these e.g. for construction purposes. This paper shows the results obtained after the wet mechanical treatment of fine MSW 10-60mm with a wet jigger. The physical principle of this process is the separation of the mass flux due to the different densities of the waste constituents. As a result, three main waste fluxes are obtained: Dense inert and dense fine fraction with a high content of minerals and a lightweight fraction with a high calorific value between 16 and 20MJ/kg. An additional positive effect of wet mechanical treatment is the removal of the finest particles from the surface of the waste material, thus increasing the quality of the generated waste fluxes. The mass fluxes of the different fractions and their qualities as well as possible recovery paths are described below. An economical and ecological consideration of the treatment of the fine materials does not take place within the framework of

  3. Rapid Development of Wet Adhesion between Carboxymethylcellulose Modified Cellulose Surfaces Laminated with Polyvinylamine Adhesive.

    Science.gov (United States)

    Gustafsson, Emil; Pelton, Robert; Wågberg, Lars

    2016-09-14

    The surface of regenerated cellulose membranes was modified by irreversible adsorption of carboxymethylcellulose (CMC). Pairs of wet CMC-modified membranes were laminated with polyvinylamine (PVAm) at room temperature, and the delamination force for wet membranes was measured for both dried and never-dried laminates. The wet adhesion was studied as a function of PVAm molecular weight, amine content, and deposition pH of the polyelectrolyte. Surprisingly the PVAm-CMC system gave substantial wet adhesion that exceeded that of TEMPO-oxidized membranes with PVAm for both dried and never-dried laminates. The greatest wet adhesion was achieved for fully hydrolyzed high molecular weight PVAm. Bulk carboxymethylation of cellulose membranes gave inferior wet adhesion combined with PVAm as compared to CMC adsorption which indicates that a CMC layer of the order of 10 nm was necessary. There are no obvious covalent cross-linking reactions between CMC and PVAm at room temperature, and on the basis of our results, we are instead attributing the wet adhesion to complex formation between the PVAm and the irreversibly adsorbed CMC at the cellulose surface. We propose that interdigitation of PVAm chains into the CMC layer is responsible for the high wet adhesion values.

  4. Mold management of wetted carpet.

    Science.gov (United States)

    Ong, Kee-Hean; Dixit, Anupma; Lewis, Roger D; MacDonald Perkins, Maureen; Backer, Denis; Condoor, Sridhar; Emo, Brett; Yang, Mingan

    2014-01-01

    This study evaluated the growth and removal of fungi on wetted carpet using newly designed technologies that rely on physical principles of steam, heat, and fluid flow. Sixty samples of carpet were embedded with heat-treated house dust, followed by embedding, wearing with a hexapod, and wetting. Samples were inoculated using a liquid suspension of Cladosporium sphaerospermum prior to placement over a water-saturated foam pad. Incubation times were 24 hr, 7 days, and 30 days. Cleaning was performed using three methods; high-flow hot water extraction, hot water and detergent, and steam. Fungal loading increased from approximately 1500 colony forming units per area (CFU/cm(2)) in 24 hr to a maximum of approximately 10,200 CFU/cm(2) after 7 days with a slight decline to 9700 CFU/cm(2) after 30 days incubation. Statistically significant differences were found among all three methods for removal of fungi for all three time periods (p mold spore decline from wetted carpet after 24 hr and 30 days, and over 92% efficiency after 7 days. The alternative methods exhibited lower efficiencies with a decline over time, from a maximum of 82% and 81% at 24 hr down to 60% and 43% at 30 days for detergent-hot water and high-flow, hot water extraction, respectively. The net effect of the mold management study demonstrates that while steam has a consistent fungal removal rate, the detergent and high-flow, hot water methods decline in efficiency with increasing incubation time.

  5. Coal combustion by wet oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Bettinger, J.A.; Lamparter, R.A.; McDowell, D.C.

    1980-11-15

    The combustion of coal by wet oxidation was studied by the Center for Waste Management Programs, of Michigan Technological University. In wet oxidation a combustible material, such as coal, is reacted with oxygen in the presence of liquid water. The reaction is typically carried out in the range of 204/sup 0/C (400/sup 0/F) to 353/sup 0/C (650/sup 0/F) with sufficient pressure to maintain the water present in the liquid state, and provide the partial pressure of oxygen in the gas phase necessary to carry out the reaction. Experimental studies to explore the key reaction parameters of temperature, time, oxidant, catalyst, coal type, and mesh size were conducted by running batch tests in a one-gallon stirred autoclave. The factors exhibiting the greatest effect on the extent of reaction were temperature and residence time. The effect of temperature was studied from 204/sup 0/C (400/sup 0/F) to 260/sup 0/C (500/sup 0/F) with a residence time from 600 to 3600 seconds. From this data, the reaction activation energy of 2.7 x 10/sup 4/ calories per mole was determined for a high-volatile-A-Bituminous type coal. The reaction rate constant may be determined at any temperature from the activation energy using the Arrhenius equation. Additional data were generated on the effect of mesh size and different coal types. A sample of peat was also tested. Two catalysts were evaluated, and their effects on reaction rate presented in the report. In addition to the high temperature combustion, low temperature desulfurization is discussed. Desulfurization can improve low grade coal to be used in conventional combustion methods. It was found that 90% of the sulfur can be removed from the coal by wet oxidation with the carbon untouched. Further desulfurization studies are indicated.

  6. Project Temporalities

    DEFF Research Database (Denmark)

    Tryggestad, Kjell; Justesen, Lise; Mouritsen, Jan

    2013-01-01

    Purpose – The purpose of this paper is to explore how animals can become stakeholders in interaction with project management technologies and what happens with project temporalities when new and surprising stakeholders become part of a project and a recognized matter of concern to be taken...... into account. Design/methodology/approach – The paper is based on a qualitative case study of a project in the building industry. The authors use actor-network theory (ANT) to analyze the emergence of animal stakeholders, stakes and temporalities. Findings – The study shows how project temporalities can...... multiply in interaction with project management technologies and how conventional linear conceptions of project time may be contested with the emergence of new non-human stakeholders and temporalities. Research limitations/implications – The study draws on ANT to show how animals can become stakeholders...

  7. Wet/Dry Vacuum Cleaner

    Science.gov (United States)

    Reimers, Harold; Andampour, Jay; Kunitser, Craig; Thomas, Ike

    1995-01-01

    Vacuum cleaner collects and retains dust, wet debris, and liquids. Designed for housekeeping on Space Station Freedom, it functions equally well in normal Earth Gravity or in microgravity. Generates acoustic noise at comfortably low levels and includes circuitry that reduces electromagnetic interference to other electronic equipment. Draws materials into bag made of hydrophobic sheet with layers of hydrophilic super-absorbing pads at downstream end material. Hydrophilic material can gel many times its own weight of liquid. Blower also provides secondary airflow to cool its electronic components.

  8. Elucidating the mysteries of wetting.

    Energy Technology Data Exchange (ETDEWEB)

    Webb, Edmund Blackburn, III (,; ); Bourdon, Christopher Jay; Grillet, Anne Mary; Sackinger, Philip A.; Grest, Gary Stephen; Emerson, John Allen; Ash, Benjamin Jesse; Heine, David R.; Brooks, Carlton, F.; Gorby, Allen D.

    2005-11-01

    Nearly every manufacturing and many technologies central to Sandia's business involve physical processes controlled by interfacial wetting. Interfacial forces, e.g. conjoining/disjoining pressure, electrostatics, and capillary condensation, are ubiquitous and can surpass and even dominate bulk inertial or viscous effects on a continuum level. Moreover, the statics and dynamics of three-phase contact lines exhibit a wide range of complex behavior, such as contact angle hysteresis due to surface roughness, surface reaction, or compositional heterogeneities. These thermodynamically and kinetically driven interactions are essential to the development of new materials and processes. A detailed understanding was developed for the factors controlling wettability in multicomponent systems from computational modeling tools, and experimental diagnostics for systems, and processes dominated by interfacial effects. Wettability probed by dynamic advancing and receding contact angle measurements, ellipsometry, and direct determination of the capillary and disjoining forces. Molecular scale experiments determined the relationships between the fundamental interactions between molecular species and with the substrate. Atomistic simulations studied the equilibrium concentration profiles near the solid and vapor interfaces and tested the basic assumptions used in the continuum approaches. These simulations provide guidance in developing constitutive equations, which more accurately take into account the effects of surface induced phase separation and concentration gradients near the three-phase contact line. The development of these accurate models for dynamic multicomponent wetting allows improvement in science based engineering of manufacturing processes previously developed through costly trial and error by varying material formulation and geometry modification.

  9. Process of forming catalytic surfaces for wet oxidation reactions

    Science.gov (United States)

    Jagow, R. B. (Inventor)

    1977-01-01

    A wet oxidation process was developed for oxidizing waste materials, comprising dissolved ruthenium salt in a reactant feed stream containing the waste materials. The feed stream is introduced into a reactor, and the reactor contents are then raised to an elevated temperature to effect deposition of a catalytic surface of ruthenium black on the interior walls of the reactor. The feed stream is then maintained in the reactor for a period of time sufficient to effect at least partial oxidation of the waste materials.

  10. Estimates of Asian dust deposition over the Asian region by using ADAM2 in 2007.

    Science.gov (United States)

    Park, Soon-Ung; Choe, Anna; Park, Moon-Soo

    2010-05-01

    The Asian Dust Aerosol Model 2 (ADAM2) with the MM5 meteorological model has been employed to estimate the dust concentration, and wet and dry depositions of dust in the Asian region for the year of 2007. It is found that the model simulates quite reasonably the dust (PM(10)) concentrations both in the dust source region (100-110 degrees E and 37-43 degrees N) and the downstream region of Korea. The starting and ending times of most of dust events and their peak concentration occurring times are well simulated. The annual average dust (PM(10)) concentration near the surface is found to be 171microgm(-3) over the dust source area, 39microgm(-3) over the Yellow Sea, 25microgm(-3) over the Korean peninsula and 17microgm(-3) over the East Sea. It is also found that the annual total deposition of dust is about 118.1tkm(-2) (dry deposition, 101.4tkm(-2); wet deposition, 16.7tkm(-2)) in the dust source region, 19.0tkm(-2) (dry deposition, 7.8tkm(-2); wet deposition, 11.2tkm(-2)) in the Yellow Sea, 12.6tkm(-2) (dry deposition, 6.5tkm(-2); wet deposition, 6.1tkm(-2)) in the Korean peninsula and 10.7tkm(-2) (dry deposition, 2.1tkm(-2); wet deposition, 8.6tkm(-2)) in the East Sea. Their ratios of wet deposition to total deposition of dust in the respective regions are 14%, 59%, 48% and 80%. This clearly indicates that the main dust removal mechanism from the atmosphere is dry deposition over the source region whereas wet deposition predominates in the downstream region of the sea. The estimated dust deposition could adversely impact the eco-environmental system in the downstream regions of the dust source region significantly. Copyright 2010 Elsevier B.V. All rights reserved.

  11. SEWER-SEDIMENT CONTROL: OVERVIEW OF AN EPA WET-WEATHER FLOW RESEARCH PROGRAM

    Science.gov (United States)

    This paper presents a historical overview of the sewer sediment control projects conducted by the Wet-Weather Flow Research Program of the USEPA. Research presented includes studies of the causes of sewer solids deposition and development/evaluation of control methods that can pr...

  12. Differential wetting characterization of hair fibers.

    Science.gov (United States)

    Vaynberg, Abe; Stuart, Mark; Wu, Xiang-Fa

    2012-01-01

    Surface wetting is one of the key properties of human hair used to indicate the extent of chemical/mechanical damage and the outcome of conditioning treatment. Characterization of hair wetting property is a challenging task due to the non-homogeneous nature of hair fibers and the requirement for sensitive equipment. Motivated by these considerations, we developed a new methodology, termed a differential wetting characterization (DWC), which would allow rapid and reliable characterization of the wetting property of hair fibers. This method is based on observation of a number of droplets suspended on a pair of parallel fibers stretched in a horizontal plane. The wetting behavior of the fibers can be deduced from the shape assumed by the droplets. When the wetting properties of the two hair fibers are identical, the droplets suspended between the fibers assume a symmetric configuration. In contrast, on the fibers with dissimilar wetting characteristics, the droplets will assume a skewed configuration towards a more hydrophilic fiber. This makes it possible to differentiate the hydrophobicities of the tested fibers. In this paper it is demonstrated that the proposed DWC method is capable of differentiating the changes in wetting property of hair surfaces in response to either chemical or physical treatment. Results of the paper indicate that the DWC method is applicable for broad wetting differentiation of various fibers.

  13. Carbon nanotube fiber spun from wetted ribbon

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Yuntian T; Arendt, Paul; Zhang, Xiefei; Li, Qingwen; Fu, Lei; Zheng, Lianxi

    2014-04-29

    A fiber of carbon nanotubes was prepared by a wet-spinning method involving drawing carbon nanotubes away from a substantially aligned, supported array of carbon nanotubes to form a ribbon, wetting the ribbon with a liquid, and spinning a fiber from the wetted ribbon. The liquid can be a polymer solution and after forming the fiber, the polymer can be cured. The resulting fiber has a higher tensile strength and higher conductivity compared to dry-spun fibers and to wet-spun fibers prepared by other methods.

  14. Uncertainty associated with convective wet removal of entrained aerosols in a global climate model

    Directory of Open Access Journals (Sweden)

    B. Croft

    2012-11-01

    Full Text Available The uncertainties associated with the wet removal of aerosols entrained above convective cloud bases are investigated in a global aerosol-climate model (ECHAM5-HAM under a set of limiting assumptions for the wet removal of the entrained aerosols. The limiting assumptions for the wet removal of entrained aerosols are negligible scavenging and vigorous scavenging (either through activation, with size-dependent impaction scavenging, or with the prescribed fractions of the standard model. To facilitate this process-based study, an explicit representation of cloud-droplet-borne and ice-crystal-borne aerosol mass and number, for the purpose of wet removal, is introduced into the ECHAM5-HAM model. This replaces and is compared with the prescribed cloud-droplet-borne and ice-crystal-borne aerosol fraction scavenging scheme of the standard model.

    A 20% to 35% uncertainty in simulated global, annual mean aerosol mass burdens and optical depth (AOD is attributed to different assumptions for the wet removal of aerosols entrained above convective cloud bases. Assumptions about the removal of aerosols entrained above convective cloud bases control modeled upper tropospheric aerosol concentrations by as much as one order of magnitude.

    Simulated aerosols entrained above convective cloud bases contribute 20% to 50% of modeled global, annual mean aerosol mass convective wet deposition (about 5% to 10% of the total dry and wet deposition, depending on the aerosol species, when including wet scavenging of those entrained aerosols (either by activation, size-dependent impaction, or with the prescribed fraction scheme. Among the simulations, the prescribed fraction and size-dependent impaction schemes yield the largest global, annual mean aerosol mass convective wet deposition (by about two-fold. However, the prescribed fraction scheme has more vigorous convective mixed-phase wet removal (by two to five-fold relative to the size-dependent impaction

  15. Surface Modification of Textured Dielectrics and Their Wetting Behavior

    Science.gov (United States)

    Kumar, Vijay; Dhillon, Ajaypal Singh; Sharma, Niti Nipun

    2017-02-01

    Controlling the wettability on dielectric materials is a classical topic in surface engineering. Surface texturing and deposition of self-assembled monolayers (SAMs) are major approaches to achieve lower or higher water contact angle ( θ c) and thereby making surface less or more wettable (more hydrophobic). Dielectric surfaces wetting has been engineered by surface modification and has been shown to achieve θ c to a maximum of 120° ± 5°. Further improvement in θ c to an extent greater than 150° ± 5° is desired to render the surface superhydrophobic. We report in this work an achievement of θ c > 150° ± 5° by combining the plasma-treated surface and octadecyltrichlorosilane (OTS) SAMs deposition on dielectrics, and this had been shown on dielectric ranging from low- k to high- k values. The improvement in wetting behavior and quality of dielectric surface with monolayer on plasma-treated surfaces are (is) investigated and characterized using atomic-force microscope (AFM), scanning electron microscope (SEM), contact angle goniometer, and Raman spectroscopy and x-ray photoelectron spectroscopy (XPS) and are compared with untreated dielectric surface with OTS monolayers.

  16. Quantifying atmospheric nitrogen deposition through a nationwide monitoring network across China

    Science.gov (United States)

    Xu, W.; Luo, X. S.; Pan, Y. P.; Zhang, L.; Tang, A. H.; Shen, J. L.; Zhang, Y.; Li, K. H.; Wu, Q. H.; Yang, D. W.; Zhang, Y. Y.; Xue, J.; Li, W. Q.; Li, Q. Q.; Tang, L.; Lu, S. H.; Liang, T.; Tong, Y. A.; Liu, P.; Zhang, Q.; Xiong, Z. Q.; Shi, X. J.; Wu, L. H.; Shi, W. Q.; Tian, K.; Zhong, X. H.; Shi, K.; Tang, Q. Y.; Zhang, L. J.; Huang, J. L.; He, C. E.; Kuang, F. H.; Zhu, B.; Liu, H.; Jin, X.; Xin, Y. J.; Shi, X. K.; Du, E. Z.; Dore, A. J.; Tang, S.; Collett, J. L., Jr.; Goulding, K.; Zhang, F. S.; Liu, X. J.

    2015-07-01

    Global reactive nitrogen (Nr) deposition to terrestrial ecosystems has increased dramatically since the industrial revolution. This is especially true in recent decades in China due to continuous economic growth. However, there are no comprehensive reports of both measured dry and wet Nr deposition across China. We therefore conducted a multiple-year study during the period mainly from 2010 to 2014 to monitor atmospheric concentrations of five major Nr species of gaseous NH3, NO2 and HNO3, and inorganic nitrogen (NH4+ and NO3-) in both particles and precipitation, based on a Nationwide Nitrogen Deposition Monitoring Network (NNDMN, covering 43 sites) in China. Wet deposition fluxes of Nr species were measured directly; dry deposition fluxes were estimated using airborne concentration measurements and inferential models. Our observations reveal large spatial variations of atmospheric Nr concentrations and dry and wet Nr deposition. The annual average concentrations (1.3-47.0 μg N m-3) and dry plus wet deposition fluxes (2.9-75.2 kg N ha-1 yr-1) of inorganic Nr species ranked by region as North China > Southeast China > Southwest China > Northeast China > Northwest China > the Tibetan Plateau or by land use as urban > rural > background sites, reflecting the impact of anthropogenic Nr emission. Average dry and wet N deposition fluxes were 18.5 and 19.3 kg N ha-1 yr-1, respectively, across China, with reduced N deposition dominating both dry and wet deposition. Our results suggest atmospheric dry N deposition is equally important to wet N deposition at the national scale and both deposition forms should be included when considering the impacts of N deposition on environment and ecosystem health.

  17. Atmospheric deposition of polychlorinated dibenzo- p-dioxins and dibenzofurans (PCDD/Fs) in Guangzhou, China

    Science.gov (United States)

    Ren, Man; Peng, Ping'an; Zhang, Sukun; Yu, Liping; Zhang, Gan; Mai, Bixian; Sheng, Guoying; Fu, Jiamo

    Atmospheric deposition of polychlorinated dibenzo- p-dioxins and dibenzofurans (PCDD/Fs) was investigated at four locations, namely at Yuancun, Wushan, Haizhu and Changban in Guangzhou City, Guangdong Province. The annual deposition fluxes of tetra- to octa-CDD/Fs (total PCDD/Fs) were found to range from 170 to 3000 (mean 1500) pg m -2 day -1, and the fluxes of total 2, 3, 7, 8-substituted PCDD/F congeners ranged from 2.1 to 41 (mean 20) pg WHO-TEQ m -2 day -1 at Wushan. The average deposition fluxes of total 2, 3, 7, 8-substituted PCDD/F congeners in rainy season were found to be 37, 27 and 28 pg WHO-TEQ m -2 day -1 at Yuancun, Haizhu and Changban, respectively, and the PCDD/F deposition fluxes behaved obviously higher in rainy season than in dry season. Results from regression analysis showed that number of rainy days, the amount of wet precipitation, PCDD/F concentrations in particles and organic carbon content played important roles in the variation of PCDD/F deposition fluxes. Monthly average temperatures change little over the year. Therefore, it only played a minor role in monthly variation of PCDD/F deposition fluxes. Particle deposition fluxes were generally not considered as the factor that could cause the differences in PCDD/F deposition fluxes between rainy and dry season, but were found to be related with PCDD/F deposition fluxes in rainy season or dry season. It was found that the profiles of PCDD/F homologs or congeners in the samples were the same either spatially or temporally, indicating that the PCDD/F emission sources were similar to one another. The similarities in PCDD/F homolog patterns and the differences in deposition fluxes between samples collected from heavy-traffic roadside and nearby residence house roof indicated that vehicle exhaust might be an important source for PCDD/F in Guangzhou. PCDD/F concentrations and profiles of PCDD/F homologs in atmospheric deposition were compared with those in both total suspended particles in air and

  18. Temporal and spatial variation of trace elements in atmospheric deposition around the industrial area of Puchuncaví-Ventanas (Chile) and its influence on exceedances of lead and cadmium critical loads in soils.

    Science.gov (United States)

    Rueda-Holgado, F; Calvo-Blázquez, L; Cereceda-Balic, F; Pinilla-Gil, E

    2016-02-01

    Fractionation of elemental contents in atmospheric samples is useful to evaluate pollution levels for risk assessment and pollution sources assignment. We present here the main results of long-term characterization of atmospheric deposition by using a recently developed atmospheric elemental fractionation sampler (AEFS) for major and trace elements monitoring around an important industrial complex located in Puchuncaví region (Chile). Atmospheric deposition samples were collected during two sampling campaigns (2010 and 2011) at four sampling locations: La Greda (LG), Los Maitenes (LM), Puchuncaví (PU) and Valle Alegre (VA). Sample digestion and ICP-MS gave elements deposition values (Al, As, Ba, Cd, Co, Cu, Fe, K, Mn, Pb, Sb, Ti, V and Zn) in the insoluble fraction of the total atmospheric deposition. Results showed that LG location, the closest location to the industrial complex, was the more polluted sampling site having the highest values for the analyzed elements. PU and LM were the next more polluted and, finally, the lowest elements concentrations were registered at VA. The application of Principal Component Analysis and Cluster Analysis identified industrial, traffic and mineral-crustal factors. We found critical loads exceedances for Pb at all sampling locations in the area affected by the industrial emissions, more significant in LG close to the industrial complex, with a trend to decrease in 2011, whereas no exceedances due to atmospheric deposition were detected for Cd. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Defined wetting properties of optical surfaces

    Science.gov (United States)

    Felde, Nadja; Coriand, Luisa; Schröder, Sven; Duparré, Angela; Tünnermann, Andreas

    2017-10-01

    Optical surfaces equipped with specific functional properties have attracted increasing importance over the last decades. In the light of cost reduction, hydrophobic self-cleaning behavior is aspired. On the other side, hydrophilic properties are interesting due to their anti-fog effect. It has become well known that such wetting states are significantly affected by the surface morphology. For optical surfaces, however, this fact poses a problem, as surface roughness can induce light scattering. The generation of optical surfaces with specific wetting properties, hence, requires a profound understanding of the relation between the wetting and the structural surface properties. Thus, our work concentrates on a reliable acquisition of roughness data over a wide spatial frequency range as well as on the comprehensive description of the wetting states, which is needed for the establishment of such correlations. We will present our advanced wetting analysis for nanorough optical surfaces, extended by a vibration-based procedure, which is mainly for understanding and tailoring the wetting behavior of various solid-liquid systems in research and industry. Utilizing the relationships between surface roughness and wetting, it will be demonstrated how different wetting states for hydrophobicity and hydrophilicity can be realized on optical surfaces with minimized scatter losses.

  20. 7 CFR 29.1083 - Wet (W).

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Wet (W). 29.1083 Section 29.1083 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Type 92) § 29.1083 Wet (W). Any sound tobacco containing excessive moisture to the extent that it is in...

  1. 7 CFR 29.2570 - Wet (W).

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Wet (W). 29.2570 Section 29.2570 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing...-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2570 Wet (W). Any sound tobacco containing...

  2. 7 CFR 29.3077 - Wet (W).

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Wet (W). 29.3077 Section 29.3077 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Wet (W). Any sound tobacco containing excessive moisture to the extent that it is in an unsafe or...

  3. 7 CFR 29.2316 - Wet (W).

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Wet (W). 29.2316 Section 29.2316 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Standards Official Standard Grades for Virginia Fire-Cured Tobacco (u.s. Type 21) § 29.2316 Wet (W...

  4. 7 CFR 29.3567 - Wet (W).

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Wet (W). 29.3567 Section 29.3567 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Type 95) § 29.3567 Wet (W). Any sound tobacco containing excessive moisture to the extent that it is in...

  5. Characteristics of wet work in nurses

    NARCIS (Netherlands)

    Jungbauer, FHW; Steenstra, FB; Groothoff, JW; Coenraads, PJ

    Background objectives: Nursing is known for its high prevalence of hand dermatitis, mainly caused by the intense exposure to wet work in nursing activities. We aimed to study the characteristics of wet work exposure in nursing. Method: Trained observers monitored the duration and frequency of

  6. SAR-sensing of vegetation wetness

    NARCIS (Netherlands)

    de Jong, JJM; Klaassen, W

    1998-01-01

    The goal of this study is to measure rain induced forest canopy wetness. The approach used is ERS tandem mission C-band SAR backscatter change detection between successive dry and rainy days. The observed backscatter change is positively related with modelled canopy wetness change. It is therefore

  7. Wet work in relation to occupational dermatitis

    NARCIS (Netherlands)

    Jungbauer, Franciscus Henricus Wilhelmus

    2004-01-01

    This thesis describes the nature and the quantity of work-related skin exposure in occupations where ‘wet work’ is performed. Activities that cause one or both hands to become wet, in contact with detergents or other skin irritating substances or activities that need to be done with occlusive gloves

  8. Porous Gold Films Fabricated by Wet-Chemistry Processes

    Directory of Open Access Journals (Sweden)

    Aymeric Pastre

    2016-01-01

    Full Text Available Porous gold films presented in this paper are formed by combining gold electroless deposition and polystyrene beads templating methods. This original approach allows the formation of conductive films (2 × 106 (Ω·cm−1 with tailored and interconnected porosity. The porous gold film was deposited up to 1.2 μm on the silicon substrate without delamination. An original zirconia gel matrix containing gold nanoparticles deposited on the substrate acts both as an adhesion layer through the creation of covalent bonds and as a seed layer for the metallic gold film growth. Dip-coating parameters and gold electroless deposition kinetics have been optimized in order to create a three-dimensional network of 20 nm wide pores separated by 20 nm thick continuous gold layers. The resulting porous gold films were characterized by GIXRD, SEM, krypton adsorption-desorption, and 4-point probes method. The process is adaptable to different pore sizes and based on wet-chemistry. Consequently, the porous gold films presented in this paper can be used in a wide range of applications such as sensing, catalysis, optics, or electronics.

  9. Dynamic wetting at the nanoscale

    Science.gov (United States)

    Amberg, Gustav; Nakamura, Yoshinori; Carlson, Andreas; Shiomi, Junichiro

    2013-11-01

    Although the capillary spreading of a drop on a dry substrate is well studied, the physical mechanisms that govern the dynamics remain challenging. Here we study the dynamics of spreading of partially wetting nano-droplets, by combining molecular dynamics and continuum simulations. The latter accounts for all the relevant hydrodynamics, i.e. capillarity, inertia and viscous stresses. By coordinated continuum and molecular dynamics simulations, the macroscopic model parameters are extracted. For a Lennard-Jones fluid spreading on a planar surface, the liquid slip on the substrate is found to be crucial for the motion of the contact line. Evaluation of the different contributions to the energy transfer shows that the liquid slip generates dissipation of the same order as the bulk viscous dissipation or the energy transfer to kinetic energy. We also study the dynamics of spreading on a substrate with a periodic nanostructure. Here it is found that a nanostructure with a length scale commensurate with molecular size completely inhibits the liquid slip. This reduces the spreading speed by about 30%. This work is partially supported by the Japan Science and Technology Agency, CREST, the Swedish Research Council, the Japan Society for the Promotion of Science, and the Sasakawa foundation.

  10. Temporal naturalism

    Science.gov (United States)

    Smolin, Lee

    2015-11-01

    Two people may claim both to be naturalists, but have divergent conceptions of basic elements of the natural world which lead them to mean different things when they talk about laws of nature, or states, or the role of mathematics in physics. These disagreements do not much affect the ordinary practice of science which is about small subsystems of the universe, described or explained against a background, idealized to be fixed. But these issues become crucial when we consider including the whole universe within our system, for then there is no fixed background to reference observables to. I argue here that the key issue responsible for divergent versions of naturalism and divergent approaches to cosmology is the conception of time. One version, which I call temporal naturalism, holds that time, in the sense of the succession of present moments, is real, and that laws of nature evolve in that time. This is contrasted with timeless naturalism, which holds that laws are immutable and the present moment and its passage are illusions. I argue that temporal naturalism is empirically more adequate than the alternatives, because it offers testable explanations for puzzles its rivals cannot address, and is likely a better basis for solving major puzzles that presently face cosmology and physics. This essay also addresses the problem of qualia and experience within naturalism and argues that only temporal naturalism can make a place for qualia as intrinsic qualities of matter.

  11. Technical Efficiency of Wet Season Melon Farming

    Directory of Open Access Journals (Sweden)

    Ananti Yekti

    2017-03-01

    Full Text Available Melon is one of high-value horticulture commodity which is cultivated widely in Kulon Progo regency. The nature of agricultural products is heavily dependent on the season, so it causes the prices of agricultural products always fluctuated every time. In wet season the price of agricultural products tends to be more expensive. Melon cultivation in wet season provide an opportunity to earn higher profits than in the dry season. The price of agricultural products tends to be more expensive in wet season, thus melon cultivation in wet season prospectively generate high profits. In order to achieve high profitability, melon farming has to be done efficiently. Objective of this study was to 1 determined the factors that influence melon production in wet season 2 measured technical efficiency of melon farming and 3 identified the factors that influanced technical efficiency. Data collected during April – June 2014. Location determined by multistage cluster sampling. 45 samples of farmers who cultivated melon during wet season obtained based on quota sampling technique. Technical efficiency was measured using Cobb-Douglas Stochastic Frontier. The result reveals that 1 land use, quantity of seed, K fertilizer contributed significantly increasing melon production, while N fertilizer decreased melon production significantly 2 technical efficiency indeces ranged from 0.40 to 0.99, with a mean of  0.77; 3 farmer’s experience gave significant influence to technical efficiency of melon farming in wet season.

  12. Variability of mineral dust deposition in the western Mediterranean basin and south-east of France

    Directory of Open Access Journals (Sweden)

    J. Vincent

    2016-07-01

    Full Text Available Previous studies have provided some insight into the Saharan dust deposition at a few specific locations from observations over long time periods or intensive field campaigns. However, no assessment of the dust deposition temporal variability in connection with its regional spatial distribution has been achieved so far from network observations over more than 1 year. To investigate dust deposition dynamics at the regional scale, five automatic deposition collectors named CARAGA (Collecteur Automatique de Retombées Atmosphériques insolubles à Grande Autonomie in French have been deployed in the western Mediterranean region during 1 to 3 years depending on the station. The sites include, from south to north, Lampedusa, Majorca, Corsica, Frioul and Le Casset (southern French Alps. Deposition measurements are performed on a common weekly period at the five sites. The mean dust deposition fluxes are higher close to the northern African coasts and decrease following a south–north gradient, with values from 7.4 g m−2 year−1 in Lampedusa (35°31′ N, 12°37′ E to 1 g m−2 year−1 in Le Casset (44°59′ N, 6°28′ E. The maximum deposition flux recorded is of 3.2 g m−2 wk−1 in Majorca with only two other events showing more than 1 g m−2 wk−1 in Lampedusa, and a maximum of 0.5 g m−2 wk−1 in Corsica. The maximum value of 2.1 g m−2 year−1 observed in Corsica in 2013 is much lower than existing records in the area over the 3 previous decades (11–14 g m−2 year−1. From the 537 available samples, 98 major Saharan dust deposition events have been identified in the records between 2011 and 2013. Complementary observations provided by both satellite and air mass trajectories are used to identify the dust provenance areas and the transport pathways from the Sahara to the stations for the studied period. Despite the large size of African dust plumes detected by satellites, more

  13. Atmospheric Ionic Deposition in Tropical Sites of Central Sulawesi Determined by Ion Exchange Resin Collectors and Bulk Water Collector.

    Science.gov (United States)

    Köhler, S; Jungkunst, H F; Gutzler, C; Herrera, R; Gerold, G

    2012-09-01

    In the light of global change, the necessity to monitor atmospheric depositions that have relevant effects on ecosystems is ever increasing particularly for tropical sites. For this study, atmospheric ionic depositions were measured on tropical Central Sulawesi at remote sites with both a conventional bulk water collector system (BWS collector) and with a passive ion exchange resin collector system (IER collector). The principle of IER collector to fix all ionic depositions, i.e. anions and cations, has certain advantages referring to (1) post-deposition transformation processes, (2) low ionic concentrations and (3) low rainfall and associated particulate inputs, e.g. dust or sand. The ionic concentrations to be measured for BWS collectors may easily fall below detection limits under low deposition conditions which are common for tropical sites of low land use intensity. Additionally, BWS collections are not as independent from the amount of rain fallen as are IER collections. For this study, the significant differences between both collectors found for nearly all measured elements were partly correlated to the rainfall pattern, i.e. for calcium, magnesium, potassium and sodium. However, the significant differences were, in most cases, not highly relevant. More relevant differences between the systems were found for aluminium and nitrate (434-484 %). Almost five times higher values for nitrate clarified the advantage of the IER system particularly for low deposition rate which is one particularity of atmospheric ionic deposition in tropical sites of extensive land use. The monthly resolution of the IER data offers new insights into the temporal distribution of annual ionic depositions. Here, it did not follow the tropical rain pattern of a drier season within generally wet conditions.

  14. Atmospheric deposition 2000. NOVA 2003; Atmosfaerisk deposition 2000. NOVA 2003

    Energy Technology Data Exchange (ETDEWEB)

    Ellermann, T.; Hertel, O.; Hovmand, M.F.; Kemp, K.; Skjoeth, C.A.

    2001-11-01

    This report presents measurements and calculations from the atmospheric part of NOVA 2003 and covers results for 2000. It summarises the main results concerning concentrations and depositions of nitrogen, phosphorus and sulphur compounds related to eutrophication and acidification. Depositions of atmospheric compounds to Danish marine waters as well as land surface are presented. Measurements: In 2000 the monitoring program consisted of eight stations where wet deposition of ammonium, nitrate, phosphate (semi quantitatively) and sulphate were measured using bulk precipitation samplers. Six of the stations had in addition measurements of atmospheric content of A, nitrogen, phosphorus, and sulphur compounds in gas and particulate phase carried out by use of filter pack samplers. Filters were analysed at the National Environmental Research Institute. Furthermore nitrogen dioxide were measured using nitrogen dioxide filter samplers and monitors. Model calculations: The measurements in the monitoring program were supplemented with model calculations of concentrations and depositions of nitrogen and sulphur compounds to Danish land surface, marine waters, fjords and bays using the ACDEP model (Atmospheric Chemistry and Deposition). The model is a so-called trajectory model and simulates the physical and chemical processes in the atmosphere using meteorological and emission data as input. The advantage of combining measurements with model calculations is that the strengths of both methods is obtained. Conclusions concerning: 1) actual concentration levels at the monitoring stations, 2) deposition at the monitoring stations, 3) seasonal variations and 4) long term trends in concentrations and depositions are mainly based on the direct measurements. These are furthermore used to validate the results of the model calculations. Calculations and conclusions concerning: 1) depositions to land surface and to the individual marine water, 2) contributions from different emission

  15. National implementation of the UNECE convention on long-range transboundary air pollution (effects). Pt. 1. Deposition loads: methods, modelling and mapping results, trends

    Energy Technology Data Exchange (ETDEWEB)

    Gauger, Thomas [Federal Agricultural Research Centre, Braunschweig (DE). Inst. of Agroecology (FAL-AOE); Stuttgart Univ. (Germany). Inst. of Navigation; Haenel, Hans-Dieter; Roesemann, Claus [Federal Agricultural Research Centre, Braunschweig (DE). Inst. of Agroecology (FAL-AOE)] (and others)

    2008-09-15

    The report on the implementation of the UNECE convention on long-range transboundary air pollution Pt.1, deposition loads (methods, modeling and mapping results, trends) includes the following chapters: Introduction, deposition on air pollutants used for the input for critical loads in exceeding calculations, methods applied for mapping total deposition loads, mapping wet deposition, wet deposition mapping results, mapping dry deposition, dry deposition mapping results, cloud and fog mapping results, total deposition mapping results, modeling the air concentration of acidifying components and heavy metals, agricultural emissions of acidifying and eutrophying species.

  16. Wet granular matter a truly complex fluid

    CERN Document Server

    Herminghaus, Stephan

    2013-01-01

    This is a monograph written for the young and advanced researcher who is entering the field of wet granular matter and keen to understand the basic physical principles governing this state of soft matter. It treats wet granulates as an instance of a ternary system, consisting of the grains, a primary, and a secondary fluid. After addressing wetting phenomena in general and outlining the basic facts on dry granular systems, a chapter on basic mechanisms and their effects is dedicated to every region of the ternary phase diagram. Effects of grain shape and roughness are considered as well. Rather than addressing engineering aspects such as existing books on this topic do, the book aims to provide a generalized framework suitable for those who want to understand these systems on a more fundamental basis. Readership: For the young and advanced researcher entering the field of wet granular matter.

  17. Determining atmospheric deposition in Wyoming with IMPROVE and other national programs

    Science.gov (United States)

    Karl Zeller; Debra Youngblood Harrington; Richard Fisher; Evgeny Donev

    2000-01-01

    Atmospheric deposition is the result of air pollution gases and aerosols leaving the atmosphere as "dry" or "wet" deposition. Little is known about just how much pollution is deposited onto soils, lakes and streams. To determine the extent and trends of forest exposure to air pollution, various types of monitoring have been conducted. In this study...

  18. Biodegradation of wet-white leather

    OpenAIRE

    Ollé Otero, Lluís; Jorba Rafart, Montse; Font Vallès, Joaquim; Shendrik, Alexander; Bacardit Dalmases, Anna

    2011-01-01

    This paper deals with the study of the physical, chemical and biological processes associated with the deterioration of wet-white leather. The samples of leather were exposed for eight months to outdoor weathering and then their properties were subsequently evaluated. The results indicate that resistance and dimensional stability of wet-white (THPS-syntan) leather is higher than that of chrometanned leather. The comparative work with chrome leather was described earlier.

  19. Thermal neutron diffusion cooling in wet quartz

    Energy Technology Data Exchange (ETDEWEB)

    Drozdowicz, K. [Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, ul. Radzikowskiego 152, PL-31-342 Cracow (Poland)]. E-mail: krzysztof.drozdowicz@ifj.edu.pl; Krynicka, E. [Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, ul. Radzikowskiego 152, PL-31-342 Crakcw (Poland); Dabrowska, J. [Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, ul. Radzikowskiego 152, PL-31-342 Cracow (Poland)

    2007-07-15

    The thermal neutron diffusion parameters of a rock material depend on the rock matrix itself and on the water content. The effect has been studied in quartz by Monte Carlo (MC) simulations of the variable buckling experiment for nine series of samples. A hyperbolic dependence of the density-removed diffusion cooling coefficient on the water content shows a variability of this parameter by two orders of magnitude. The function obtained for wet quartz is compared with the analogous dependence for wet dolomite.

  20. Microbial communities associated with wet flue gas desulfurization systems

    Science.gov (United States)

    Brown, Bryan P.; Brown, Shannon R.; Senko, John M.

    2012-01-01

    Flue gas desulfurization (FGD) systems are employed to remove SOx gasses that are produced by the combustion of coal for electric power generation, and consequently limit acid rain associated with these activities. Wet FGDs represent a physicochemically extreme environment due to the high operating temperatures and total dissolved solids (TDS) of fluids in the interior of the FGD units. Despite the potential importance of microbial activities in the performance and operation of FGD systems, the microbial communities associated with them have not been evaluated. Microbial communities associated with distinct process points of FGD systems at several coal-fired electricity generation facilities were evaluated using culture-dependent and -independent approaches. Due to the high solute concentrations and temperatures in the FGD absorber units, culturable halothermophilic/tolerant bacteria were more abundant in samples collected from within the absorber units than in samples collected from the makeup waters that are used to replenish fluids inside the absorber units. Evaluation of bacterial 16S rRNA genes recovered from scale deposits on the walls of absorber units revealed that the microbial communities associated with these deposits are primarily composed of thermophilic bacterial lineages. These findings suggest that unique microbial communities develop in FGD systems in response to physicochemical characteristics of the different process points within the systems. The activities of the thermophilic microbial communities that develop within scale deposits could play a role in the corrosion of steel structures in FGD systems. PMID:23226147

  1. Structure of wet specimens in electron microscopy. Improved environmental chambers make it possible to examine wet specimens easily.

    Science.gov (United States)

    Parsons, D F

    1974-11-01

    Several recent technological advances have increased the practicality and usefulness of the technique of electron microscopy of wet objects. (i) There have been gains in the effective penetration of high-voltage microscopes, scanning transmission microscopes, and high-voltage scanning microscopes. The extra effective penetration gives more scope for obtaining good images through film windows, gas, and liquid layers. (ii) Improved methods of obtaining contrast are available (especially dark field and inelastic filtering) that often make it possible to obtain sufficient contrast with wet unstained objects. (iii) Improved environmental chamber design makes it possible to insert and examine wet specimens as easily as dry specimens. The ultimate achievable resolution for wet objects in an environmental chamber will gradually become clear experimentally. Resolution is mainly a function of gas path, liquid and wet specimen thickness, specimen stage stability, acceleration voltage, and image mode (fixed or scanning beam) (13). Much depends on the development of the technique for controlling the thickness of extraneous water film around wet objects or the technique for depositing wet objects onto dry, hydrophobic support films. Although some loss of resolution due to water or gas scattering will always occur, an effective gain is anticipated in preserving the shape of individual molecules and preventing the partial collapse that usually occurs on drying or negative staining. The most basic question for biological electron microscopy is probably whether any living functions of cells can be observed so that the capabilities of the phase contrast and interference light microscopes can be extended. Investigators are now rapidly approaching a final answer to this question. The two limiting factors are (i) maintaining cell motility in spread cells immersed in thin layers of media and (ii) reducing beam radiation damage to an acceptable level. The use of sensitive emulsions and

  2. Investigation of Precipitation Variations over Wet and Dry Areas from Observation and Model

    Directory of Open Access Journals (Sweden)

    James H. Trammell

    2015-01-01

    Full Text Available Our observational study revealed that the precipitation increased over the wet area and decreased over the dry area during the past two decades. Here, we further investigate whether the current atmospheric models can quantitatively capture the characteristics of precipitation from the observation. The NASA Goddard Institute for Space Studies (GISS model is used to examine the historic simulation of the precipitation, in which the historic greenhouse gases and aerosols are included in the radiative forcing. The consistency between the historic GISS simulation and the Global Precipitation Climatology Project (GPCP precipitation suggests that the model can qualitatively capture the temporal trends of precipitation over the wet and dry areas. However, the precipitation trends are weaker in the model than in the observation. The observed trends of precipitation do not appear in the control simulation with the fixed concentrations of greenhouse gases and aerosols, which suggests that the global warming due to anthropogenic forcing can influence the temporal variations of precipitation over the wet and dry areas. Diagnostic studies of other variables from the model further suggest that enhanced rising air can increase the precipitation over the wet area.

  3. Wetting and adsorption modification in the system

    Directory of Open Access Journals (Sweden)

    Yuliya Bogdanova

    2015-09-01

    Full Text Available Regularities of wetting and adsorption modification of surfaces of continual membranes made from highly permeable glassy polymers poly[1-(trimethylsilyl-1-propyne] (PTMSP and poly(4-methyl-2-pentyn (PMP with aqueous ethanol solutions and alcohol solutions containing organic dyes (Solvent Blue 35 and Remazol Brilliant Blue were investigated. Isotherms of stress wetting of polymer membrane surface by etanol solutions were found out to have maximums in the range of concentrations corresponding to the beginning of liquid sorption into the membrane and polymer swelling. Thus, the principal possibility of optimization of nanofiltration experiments by liquid wetting angle measurements on continuous polymer membrane surfaces was shown. The presence of the dye was shown not to affect PMP wetting. But in the case of PTMSP, it leads to shear of the maximum of stress wetting isotherms to the range of higher concentrations. It was found out the effectiveness of the adsorption surface modification of continuous polymer membrane surfaces by ethanol solutions containing dyes does not dependent on chemical nature of the dye. At the same time, there are different trends in the energy characteristics of the membrane surface.

  4. Membrane-based wet electrostatic precipitation.

    Science.gov (United States)

    Bayless, David J; Shi, Liming; Kremer, Gregory; Stuart, Ben J; Reynolds, James; Caine, John

    2005-06-01

    Emissions of fine particulate matter, PM2.5, in both primary and secondary form, are difficult to capture in typical dry electrostatic precipitators (ESPs). Wet (or water-based) ESPs are well suited for collection of acid aerosols and fine particulates because of greater corona power and virtually no re-entrainment. However, field disruptions because of spraying (misting) of water, formation of dry spots (channeling), and collector surface corrosion limit the applicability of current wet ESPs in the control of secondary PM2.5. Researchers at Ohio University have patented novel membrane collection surfaces to address these problems. Water-based cleaning in membrane collectors made of corrosion-resistant fibers is facilitated by capillary action between the fibers, maintaining an even distribution of water. This paper presents collection efficiency results of lab-scale and pilot-scale testing at FirstEnergy's Bruce Mansfield Plant for the membrane-based wet ESP. The data indicate that a membrane wet ESP was more effective at collecting fine particulates, acid aerosols, and oxidized mercury than the metal-plate wet ESP, even with approximately 15% less collecting area.

  5. Dynamic wetting on anisotropic patterned surfaces

    Science.gov (United States)

    Do-Quang, Minh; Wang, Jiayu; Nita, Satoshi; Shiomi, Junichiro; Amberg, Gustav; Physiochemical fluid mechanics Team; Maruyama-Chiashi Laboratory Team

    2014-11-01

    Dynamic wetting, as occurs when a droplet of a wetting liquid is brought in contact with a dry solid, is important in various engineering processes, such as printing, coating, and lubrication. Our overall aim is to investigate if and how the detailed properties of the solid surface influence the dynamics of wetting. We have recently quantified the hindering effect of fairly isotropic micron-sized patterns on the substrate. Here we will study highly anisotropic surfaces, such as parallel grooves, either perpendicular or parallel to an advancing contact line. This is done by detailed phase field simulations and experiments on structured silicon surfaces. The dynamic wetting behavior of drops on the grooved surfaces is governed by the combined interplay of the wetting line friction and the internal viscous dissipation. Influence of roughness is quantified in terms of the energy dissipation rate at the contact line using the experiment-simulation combined analysis. The energy dissipation of the contact line at the different part of the groove will be discussed. The performance of the model is assessed by comparing its predictions with the experimental data. This work was financially supported in part by, the Japan Society for the Promotion of Science (J.W., S.N., and J.S) and Swedish Governmental Agency for Innovation Systems (M.D.-Q. and G.A).

  6. Energy and heat balance in wet DCT

    Energy Technology Data Exchange (ETDEWEB)

    Saxena, Viren; Moser, Alexander; Schaefer, Michael; Ritschel, Michael [BorgWarner Drivetrain Engineering GmbH, Ketsch (Germany)

    2012-11-01

    Wet clutch systems are well known for their thermal robustness and versatility in a wide range of automotive applications. Conventional automatics have used them for a long time as torque converter lock-up clutches, shift elements and launch clutches. With the development of DCTs, wet clutch technology has evolved in terms of launch and shift performance, controllability, robustness and efficiency. This paper discusses improvements in the wet clutch and their impact on today's vehicle applications in terms of heat and energy management. Thermal robustness is a crucial aspect for an automatic transmission. In addition to the clutch thermal performance, the influence of transmission oil cooler and oil sump warm-up behavior are discussed. Based on our latest development activities, test results and simulations, we shall discuss the latest friction material enhancement and its impact on DCTs in terms of efficiency and performance. Drag loss is a much-discussed topic during the development of wet clutch systems. This paper discusses in detail the cause and break-up of various energy losses in a wet DCT. Efficient energy management strategies for actuation systems, cooling, and lubrication, clutch apply, and pre-selection in modern power trains with engine start / stop are evaluated based on the latest test and simulation results. Finally, the paper summarizes the performance and efficiency optimized moist clutch system. (orig.)

  7. Total atmospheric deposition of reduced nitrogen in the United States Pacific Northwest for 2002

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This spatial data set was created by the U.S. Geological Survey (USGS) to represent the amount of wet and dry deposition of reduced nitrogen in the Pacific Northwest...

  8. Total atmospheric deposition of oxidized nitrogen in the United States Pacific Northwest for 2002

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This spatial data set was created by the U.S. Geological Survey (USGS) to represent the amount of wet and dry deposition of oxidized nitrogen in the Pacific...

  9. Total atmospheric deposition of oxidized and reduced nitrogen in the United States Pacific Northwest for 2002

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This spatial data set was created by the U.S. Geological Survey (USGS) to represent the amount of wet and dry deposition of oxidized and reduced nitrogen in the...

  10. Advanced methods for the treatment of organic aqueous wastes: wet air oxidation and wet peroxide oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Debellefontaine, Hubert; Chakchouk, Mehrez; Foussard, Jean Noel [Institut National des Sciences Appliquees (INSA), 31 - Toulouse (France). Dept. de Genie des Procedes Industriels; Tissot, Daniel; Striolo, Phillipe [IDE Environnement S.A., Toulouse (France)

    1993-12-31

    There is a growing concern about the problems of wastes elimination. Various oxidation techniques are suited for elimination of organic aqueous wastes, however, because of the environmental drawbacks of incineration, liquid phase oxidation should be preferred. `Wet Air Oxidation` and `Wet Peroxide Oxidation`are alternative processes which are discussed in this paper. 17 refs., 13 figs., 4 tabs.

  11. Evaporation from rain-wetted forest in relation to canopy wetness, canopy cover, and net radiation

    NARCIS (Netherlands)

    Klaassen, W.

    2001-01-01

    Evaporation from wet canopies is commonly calculated using E-PM, the Penman-Monteith equation with zero surface resistance. However, several observations show a lower evaporation from rain-wetted forest. Possible causes for the difference between E-PM and experiments are evaluated to provide rules

  12. Dry and wet spell variability during monsoon in gauge-based gridded daily precipitation datasets over India

    Science.gov (United States)

    Chaudhary, Shushobhit; Dhanya, C. T.; Vinnarasi, R.

    2017-03-01

    Accurate estimates of monsoonal rainfall at daily time scales are essential inputs for various water-related sectors such as drought and flood forecasting, crop and water management for agriculture. To serve this purpose, a variety of rainfall products, especially the gauge based products which serve as the ground-truth for other derived rainfall products, are available over India. In this study, three different daily gauge based gridded rainfall datasets, namely Indian Meteorological Department (IMD), Asian Precipitation Highly Resolved Observational Data Integration Towards Evaluation of water resources (APHRODITE) and Climate Prediction Center (CPC) unified rain gauge data are compared over India for the monsoon season of 1979-2007. The comparison among the datasets is based on the duration, frequency and intensity of three different spell characteristics, namely dry, wet and extreme wet spells, and their associated trends. Wet (dry) spells are defined as the consecutive period of wet (dry) days, where a wet (dry) day is defined using rainfall threshold of 1 mm. Extreme wet spells are defined using the 90th percentile of rainfall above the depth of wet day. All datasets capture the spatial distribution of precipitation characteristics, albeit with pronounced differences at heavy rainfall regions. CPC and IMD show a close match in spell characteristics while APHRODITE significantly deviates. APHRODITE shows increased intensity of rainfall during dry periods, leading to over-estimation of wet days and under-estimation of dry days. Northern extreme of India (Jammu and Kashmir) show major differences in replicating the spell characteristics. Trend patterns are also not consistent between the three datasets. The present study will provide information on the spatio-temporal pattern of dry, wet and extreme wet spell characteristics over India and aid in selecting appropriate datasets for studying the Indian monsoon rainfall depending on their scope and application of

  13. The Role of Surface Chemistry in Adhesion and Wetting of Gecko Toe Pads

    Science.gov (United States)

    Badge, Ila; Stark, Alyssa Y.; Paoloni, Eva L.; Niewiarowski, Peter H.; Dhinojwala, Ali

    2014-10-01

    An array of micron-sized setal hairs offers geckos a unique ability to walk on vertical surfaces using van der Waals interactions. Although many studies have focused on the role of surface morphology of the hairs, very little is known about the role of surface chemistry on wetting and adhesion. We expect that both surface chemistry and morphology are important, not only to achieve optimum dry adhesion but also for increased efficiency in self-cleaning of water and adhesion under wet conditions. Here, we used a plasma-based vapor deposition process to coat the hairy patterns on gecko toe pad sheds with polar and non-polar coatings without significantly perturbing the setal morphology. By a comparison of wetting across treatments, we show that the intrinsic surface of gecko setae has a water contact angle between 70-90°. As expected, under wet conditions, adhesion on a hydrophilic surface (glass) was lower than that on a hydrophobic surface (alkyl-silane monolayer on glass). Surprisingly under wet and dry conditions the adhesion was comparable on the hydrophobic surface, independent of the surface chemistry of the setal hairs. This work highlights the need to utilize morphology and surface chemistry in developing successful synthetic adhesives with desirable adhesion and self-cleaning properties.

  14. Wet powder seal for gas containment

    Science.gov (United States)

    Stang, Louis G.

    1982-01-01

    A gas seal is formed by a compact layer of an insoluble powder and liquid filling the fine interstices of that layer. The smaller the particle size of the selected powder, such as sand or talc, the finer will be the interstices or capillary spaces in the layer and the greater will be the resulting sealing capacity, i.e., the gas pressure differential which the wet powder layer can withstand. Such wet powder seal is useful in constructing underground gas reservoirs or storage cavities for nuclear wastes as well as stopping leaks in gas mains buried under ground or situated under water. The sealing capacity of the wet powder seal can be augmented by the hydrostatic head of a liquid body established over the seal.

  15. Novel design for Konin wet FGD

    Energy Technology Data Exchange (ETDEWEB)

    Zawacki, T.; Bengtsson, S. [ZEPAK, Konin (Poland)

    1996-09-01

    The Konin Power Station, Poland, with a total production capacity of 538 MW{sub e} and 462 MW{sub th} and belonging to the ZEPAK group, is extensively rebuilding units Nos 7 and 8 and retrofitting with wet flue gas desulphurisation. ZEPAK evaluated wet FGD technologies in 1992 and 1993 and decided for a novel concrete absorber-in-stack concept for a limestone forced oxidation system, that will produce commercial grade gypsum. The FGD plant is now under construction and commissioning is scheduled to commence in first quarter of 1997. The paper will provide the background for the choice of wet FGD and present details on both execution and technology for this novel absorber-in-stack concept for power plant FGD.

  16. Controlled Deposition and Alignment of Carbon Nanotubes

    Science.gov (United States)

    Smits, Jan M. (Inventor); Wincheski, Russell A. (Inventor); Patry, JoAnne L. (Inventor); Watkins, Anthony Neal (Inventor); Jordan, Jeffrey D. (Inventor)

    2012-01-01

    A carbon nanotube (CNT) attraction material is deposited on a substrate in the gap region between two electrodes on the substrate. An electric potential is applied to the two electrodes. The CNT attraction material is wetted with a solution defined by a carrier liquid having carbon nanotubes (CNTs) suspended therein. A portion of the CNTs align with the electric field and adhere to the CNT attraction material. The carrier liquid and any CNTs not adhered to the CNT attraction material are then removed.

  17. Sphere impact and penetration into wet sand

    KAUST Repository

    Marston, J. O.

    2012-08-07

    We present experimental results for the penetration of a solid sphere when released onto wet sand. We show, by measuring the final penetration depth, that the cohesion induced by the water can result in either a deeper or shallower penetration for a given release height compared to dry granular material. Thus the presence of water can either lubricate or stiffen the granular material. By assuming the shear rate is proportional to the impact velocity and using the depth-averaged stopping force in calculating the shear stress, we derive effective viscosities for the wet granular materials.

  18. temporal variation of malaria occurrence in kano municipal local

    African Journals Online (AJOL)

    DR. AMINU

    order to prevent the disease. Keywords: Malaria, Epidemiology, Seasons, Temporal Variation, Kano. ... effect of temperature on the outbreak of Malaria. Hay et al (2002) examined the role of climate change on the resurgence of ... up of 13 wards. The climate of the area is the tropical dry and wet climate. The average annual.

  19. Spatial and temporal distribution of methane in an extensive shallow ...

    Indian Academy of Sciences (India)

    Keywords. Methane emission; spatial and temporal variation; macro-algal zone; estuaries; Pulicat lake. Abstract. Sedimentary methane (CH4) fluxes and oxidation rates were determined over the wet and dry seasons (four measurement campaigns)in Pulicat lake,an extensive shallow estuary in south India. Dissolved CH4 ...

  20. Plasma enhanced atomic layer deposition of silicon nitride using neopentasilane

    Energy Technology Data Exchange (ETDEWEB)

    Weeks, Stephen, E-mail: Stephen.Weeks@intermolecular.com; Nowling, Greg; Fuchigami, Nobi; Bowes, Michael; Littau, Karl [Intermolecular, 3011 North 1st Street, San Jose, California 95134 (United States)

    2016-01-15

    Progress in transistor scaling has increased the demands on the material properties of silicon nitride (SiN{sub x}) thin films used in device fabrication and at the same time placed stringent restrictions on the deposition conditions employed. Recently, low temperature plasma enhanced atomic layer deposition has emerged as a viable technique for depositing these films with a thermal budget compatible with semiconductor processing at sub-32 nm technology nodes. For these depositions, it is desirable to use precursors that are free from carbon and halogens that can incorporate into the film. Beyond this, it is necessary to develop processing schemes that minimize the wet etch rate of the film as it will be subjected to wet chemical processing in subsequent fabrication steps. In this work, the authors introduce low temperature deposition of SiN{sub x} using neopentasilane [NPS, (SiH{sub 3}){sub 4}Si] in a plasma enhanced atomic layer deposition process with a direct N{sub 2} plasma. The growth with NPS is compared to a more common precursor, trisilylamine [TSA, (SiH{sub 3}){sub 3 }N] at identical process conditions. The wet etch rates of the films deposited with NPS are characterized at different plasma conditions and the impact of ion energy is discussed.

  1. Wetting properties and performance test of modified rigid collector in wet electrostatic precipitators.

    Science.gov (United States)

    Xu, Chunyan; Chang, Jingcai; Meng, Zhen; Wang, Xiang; Zhang, Jing; Cui, Lin; Ma, Chunyuan

    2016-10-01

    The fine particles are considered a significant pollution problem. The wet electrostatic precipitators (ESPs) have advantages of efficient collection of the fine particles with lower pressure drop and eliminating reentrainment. The wetting properties of the collector surfaces have significantly important effect on wet ESPs' stable and secure operation. The modified rigid collector (MRC) was modified by coating specific vinyl ester resin composites and loose glass fiber cloth over the conventional carbon steel in a certain way. The rigid collector surfaces before and after modification had been characterized by scanning electron microscopy (SEM) and interface tensiometer. The effect of operating temperatures on the wetting properties of the rigid collector surfaces before and after modification was investigated. The temperature range was 40~90 °C, and the wetting properties contained liquid holdup, surface flow rate, film rate, average film thickness, and critical saturation time. The modified rigid collector surface exhibited excellent wetting properties at the operating temperatures. The fine particles collection performance compared among the MRC, the conventional rigid collector (CRC), and the flexible collector (FC) in the wet ESPs was investigated. The effects of the applied voltage, the water film, corona power, and the specific collecting area on the fine particles collection were evaluated. The modified rigid collector provided high fine particles collection effect with lower energy and water consumption. To improve the submicron particles collection efficiency and decrease energy and water consumption, the formation of uniform water film over the collector surfaces has been widely studied. The modified rigid collector was modified by coating specific vinyl ester resin composites and loose glass fiber cloth (ERGF) over the conventional carbon steel (CCS) in a certain way. The modified rigid collector surface exhibited excellent wetting properties. The wet

  2. Catalytic gasification of dry and wet biomass

    NARCIS (Netherlands)

    van Rossum, G.; Potic, B.; Kersten, Sascha R.A.; van Swaaij, Willibrordus Petrus Maria

    2009-01-01

    Catalytic gasification of dry biomass and of wet biomass streams in hot compressed water are reviewed and discussed as potential technologies for the production of synthesis gas, hydrogen- and methane-rich gas. Next to literature data also new experimental results from our laboratory on catalytic

  3. Wet oxidation of salicylic acid solutions.

    Science.gov (United States)

    Collado, Sergio; Garrido, Laura; Laca, Adriana; Diaz, Mario

    2010-11-15

    Salicylic acid is a frequent pollutant in several industrial wastewaters. Uncatalyzed wet air oxidation, which is a promising technique for the treatment of phenolic effluents, has not been analyzed yet for the removal of salicylic acid. The effect of different conditions of pH (1.3-12.3), pressure (1.0-4.1 MPa), temperature (413-443 K), and initial concentrations (1.45-14.50 mM) on the wet oxidation of salicylate/salicylic acid solutions have here been investigated. The pH value of the reaction media was found to be a key parameter for the rate of the oxidation process with an optimum at pH 3.1, when the concentrations of salicylic acid and salicylate were similar. The oxidation reaction followed pseudofirst-order kinetics with respect to salicylic acid and 0.82 order with respect to dissolved oxygen. Additionally, the evolution of the color during the wet oxidation was analyzed and discussed in relation with the formation of intermediate compounds. Then, a reaction pathway for the noncatalytic wet oxidation of the salicylic acid was proposed.

  4. Curvature controlled wetting in two dimensions

    DEFF Research Database (Denmark)

    Gil, Tamir; Mikheev, Lev V.

    1995-01-01

    layer lW, leading to a power law lW∝r01/3. At a critical wetting transition of a planar substrate, curvature adds a relevant field; the corresponding multiscaling forms are readily available. The method allows for the systematic evaluation of corrections to the leading behavior; the next to the leading...

  5. Theory of the forced wetting transition

    NARCIS (Netherlands)

    Chan, Tak Shing; Snoeijer, Jacobus Hendrikus; Eggers, J.

    2012-01-01

    We consider a solid plate being withdrawn from a bath of liquid which it does not wet. At low speeds, the meniscus rises below a moving contact line, leaving the rest of the plate dry. At a critical speed of withdrawal, this solution bifurcates into another branch via a saddle-node bifurcation: two

  6. Directional wetting on chemically patterned substrates

    NARCIS (Netherlands)

    Kooij, Ernst S.; Jansen, H.P.; Bliznyuk, O.; Poelsema, Bene; Zandvliet, Henricus J.W.

    2012-01-01

    The directional wetting behavior of chemically defined stripe-patterned anisotropic surfaces is presented. The equilibrium shapes of asymmetric droplets, arising from patterns of alternating hydrophilic and hydrophobic stripes with dimensions in the low-micrometer range, are investigated in relation

  7. Accretion Dynamics on Wet Granular Materials

    Science.gov (United States)

    Saingier, Guillaume; Sauret, Alban; Jop, Pierre

    2017-05-01

    Wet granular aggregates are common precursors of construction materials, food, and health care products. The physical mechanisms involved in the mixing of dry grains with a wet substrate are not well understood and difficult to control. Here, we study experimentally the accretion of dry grains on a wet granular substrate by measuring the growth dynamics of the wet aggregate. We show that this aggregate is fully saturated and its cohesion is ensured by the capillary depression at the air-liquid interface. The growth dynamics is controlled by the liquid fraction at the surface of the aggregate and exhibits two regimes. In the viscous regime, the growth dynamics is limited by the capillary-driven flow of liquid through the granular packing to the surface of the aggregate. In the capture regime, the capture probability depends on the availability of the liquid at the saturated interface, which is controlled by the hydrostatic depression in the material. We propose a model that rationalizes our observations and captures both dynamics based on the evolution of the capture probability with the hydrostatic depression.

  8. Cohesion and agglomeration of wet powders

    Science.gov (United States)

    Raux, Pascal S.; Biance, Anne-Laure

    2018-01-01

    Wet high-shear granulation consists in vigorously mixing grains and a liquid binder to create agglomerates of various sizes. The process results from a balance between cohesion of the wet granular agglomerates and fragmentation due to the high mixing. By performing a simple test with glass beads and various liquids, we first focus on the static cohesion of wet granular media. Contrary to previous works, we extend the study to larger values of the liquid fraction w . After the well-documented plateau, the cohesive strength increases again with w , a behavior we capture by a simple model. We then focus on the dynamical cohesion of the media and we design an agglomeration process that consists in vibrating a bead/liquid mixture at a large amplitude. The vibrations induce not only the fluidization of the wet granular material but also the formation of aggregates. As expected, their size is affected by the liquid content, the frequency, and the amplitude of the vibrations, similarly to high-shear granulation data. However, the number of beads in an agglomerate does not depend on the bead size, showing a self-similar mechanism of agglomeration. The role of the static cohesion strength in this dynamical process remains therefore ambiguous.

  9. Microwave moisture sensing of wet bales

    Science.gov (United States)

    Sensing of moisture in very wet lint bales is unique due to the fact that moisture distribution is typically non-uniform and can in some instances be highly localized. This issue is even further complicated by the use of a sensor that reads only a portion of the bale and/or with a sensor that provid...

  10. Ovine wet carcass syndrome of unknown aetiology

    African Journals Online (AJOL)

    plicating cachexia, inflammatory processes, lymphoedema, cardiac failure, glycogen storage or myxoedema in the pathogenesis of the syndrome. In conclusion, despite intensive investigation the aeti- ology of the wet carcase syndrome remains unknown. At present the possibility of a histamine reaction due to insect bites is ...

  11. Optical properties of a tropical estuary during wet and dry conditions in the Nha Phu estuary, Khanh Hoa Province, south-east Vietnam

    DEFF Research Database (Denmark)

    Lund-Hansen, Lars Chresten; Hai, Doan Nhu; Lam, Nguyen Ngoc

    2010-01-01

    There has been a strong research focus on optical properties in temperate estuaries but very much less in tropical estuaries. These properties comprise light and beam attenuation dominated by suspended particulate matter, Chl a, and CDOM. Spatially and temporally distributed data on optical...... between May 2006 and April 2008. Methods comprised CTD, optical measurements, and water sampling for suspended matter, Chl a, and CDOM. Results showed high light attenuation—K d(PAR)—in wet conditions and low in dry. K d(PAR) was highest at the estuary head and lower in the outer part. Spatial...... and temporal variations in K d(PAR) were in general dominated by variations in suspended particulate matter concentrations in both wet and dry conditions. Chl a concentrations were low and showed no strong variations between wet and dry conditions. CDOM absorption coefficients were higher in wet conditions...

  12. Spatial and Temporal Variability of Ground and Satellite Column Measurements of NO2 and O3 over the Atlantic Ocean During the Deposition of Atmospheric Nitrogen to Coastal Ecosystems Experiment

    Science.gov (United States)

    Martins, Douglas K.; Najjar, Raymond G.; Tzortziou, Maria; Abuhassan, Nader; Thompson, Anne M.; Kollonige, Debra E.

    2016-01-01

    In situ measurements of O3 and nitrogen oxides (NO + NO2=NOx) and remote sensing measurements of total column NO2 and O3 were collected on a ship in the North Atlantic Ocean as part of the Deposition of Atmospheric Nitrogen to Coastal Ecosystems (DANCE) campaign in July August 2014,100 km east of the mid-Atlantic United States. Relatively clean conditions for both surface in situ mixing ratio and total column O3 and NO2 measurements were observed throughout the campaign. Increased surface and column NO2 and O3 amounts were observed when a terrestrial air mass was advected over the study region. Relative to ship-based total column measurements using a Pandora over the entire study, satellite measurements overestimated total column NO2 under these relatively clean atmospheric conditions over offshore waters by an average of 16. Differences are most likely due to proximity, or lack thereof, to surface emissions; spatial averaging due to the field of view of the satellite instrument; and the lack of sensitivity of satellite measurements to the surface concentrations of pollutants. Total column O3 measurements from the shipboard Pandora showed good correlation with the satellite measurements(r 0.96), but satellite measurements were 3 systematically higher than the ship measurements, in agreement with previous studies. Derived values of boundary layer height using the surface in situ and total column measurements of NO2 are much lower than modeled and satellite-retrieved boundary layer heights, which highlight the differences in the vertical distribution between terrestrial and marine environments.

  13. Wet adhesion and adhesive locomotion of snails on anti-adhesive non-wetting surfaces.

    Directory of Open Access Journals (Sweden)

    Neil J Shirtcliffe

    Full Text Available Creating surfaces capable of resisting liquid-mediated adhesion is extremely difficult due to the strong capillary forces that exist between surfaces. Land snails use this to adhere to and traverse across almost any type of solid surface of any orientation (horizontal, vertical or inverted, texture (smooth, rough or granular or wetting property (hydrophilic or hydrophobic via a layer of mucus. However, the wetting properties that enable snails to generate strong temporary attachment and the effectiveness of this adhesive locomotion on modern super-slippy superhydrophobic surfaces are unclear. Here we report that snail adhesion overcomes a wide range of these microscale and nanoscale topographically structured non-stick surfaces. For the one surface which we found to be snail resistant, we show that the effect is correlated with the wetting response of the surface to a weak surfactant. Our results elucidate some critical wetting factors for the design of anti-adhesive and bio-adhesion resistant surfaces.

  14. Wet adhesion and adhesive locomotion of snails on anti-adhesive non-wetting surfaces.

    Science.gov (United States)

    Shirtcliffe, Neil J; McHale, Glen; Newton, Michael I

    2012-01-01

    Creating surfaces capable of resisting liquid-mediated adhesion is extremely difficult due to the strong capillary forces that exist between surfaces. Land snails use this to adhere to and traverse across almost any type of solid surface of any orientation (horizontal, vertical or inverted), texture (smooth, rough or granular) or wetting property (hydrophilic or hydrophobic) via a layer of mucus. However, the wetting properties that enable snails to generate strong temporary attachment and the effectiveness of this adhesive locomotion on modern super-slippy superhydrophobic surfaces are unclear. Here we report that snail adhesion overcomes a wide range of these microscale and nanoscale topographically structured non-stick surfaces. For the one surface which we found to be snail resistant, we show that the effect is correlated with the wetting response of the surface to a weak surfactant. Our results elucidate some critical wetting factors for the design of anti-adhesive and bio-adhesion resistant surfaces.

  15. Modelling and investigation of partial wetting surfaces for drop dynamics using lattice Boltzmann method

    Energy Technology Data Exchange (ETDEWEB)

    Pravinraj, T., E-mail: pravinraj1711@gmail.com; Patrikar, Rajendra

    2017-07-01

    Highlights: • A LBM model on partial wetting surface for droplet dynamics is presented by introducing a simple initial partial wetting boundary condition in SC model. • With our approach one can tune the splitting volume and time by carefully choosing strip width and position. • It is shown that the droplet spreading on chemically heterogeneous surfaces can be controlled not only by Weber number but also by tuning strip width ratio. • The directional transportation of a droplet due to chemical wetting gradient is simulated and analyzed using hybrid thermodynamic-image processing technique. • Microstructure surface and its influence on the directional wetting based transportation of droplet are demonstrated. - Abstract: Partial wetting surfaces and its influence on the droplet movement of micro and nano scale being contemplated for many useful applications. The dynamics of the droplet usually analyzed with a multiphase lattice Boltzmann method (LBM). In this paper, the influence of partial wetting surface on the dynamics of droplet is systematically analyzed for various cases. Splitting of droplets due to chemical gradient of the surface is studied and analyses of splitting time for various widths of the strips for different Weber numbers are computed. With the proposed model one can tune the splitting volume and time by carefully choosing a strip width and droplet position. The droplet spreading on chemically heterogeneous surfaces shows that the spreading can be controlled not only by parameters of Weber number but also by tuning strip width ratio. The transportation of the droplet from hydrophobic surface to hydrophilic surface due to chemical gradient is simulated and analyzed using our hybrid thermodynamic-image processing technique. The results prove that with the progress of time the surface free energy decreases with increase in spreading area. Finally, the transportation of a droplet on microstructure gradient is demonstrated. The model explains

  16. Towards General Temporal Aggregation

    DEFF Research Database (Denmark)

    Boehlen, Michael H.; Gamper, Johann; Jensen, Christian Søndergaard

    2008-01-01

    Most database applications manage time-referenced, or temporal, data. Temporal data management is difficult when using conventional database technology, and many contributions have been made for how to better model, store, and query temporal data. Temporal aggregation illustrates well the problem...

  17. Modelling transport and deposition of caesium and iodine from the Chernobyl accident using the DREAM model

    Directory of Open Access Journals (Sweden)

    J. Brandt

    2002-01-01

    Full Text Available A tracer model, DREAM (the Danish Rimpuff and Eulerian Accidental release Model, has been developed for modelling transport, dispersion and deposition (wet and dry of radioactive material from accidental releases, as the Chernobyl accident. The model is a combination of a Lagrangian model, that includes the near source dispersion, and an Eulerian model describing the long-range transport. The performance of the transport model has previously been tested within the European Tracer Experiment, ETEX, which included transport and dispersion of an inert, non-depositing tracer from a controlled release. The focus of this paper is the model performance with respect to the total deposition of  137Cs, 134Cs and 131I from the Chernobyl accident, using different relatively simple and comprehensive parameterizations for dry- and wet deposition. The performance, compared to measurements, of using different combinations of two different wet deposition parameterizations and three different parameterizations of dry deposition has been evaluated, using different statistical tests. The best model performance, compared to measurements, is obtained when parameterizing the total deposition combined of a simple method for dry deposition and a subgrid-scale averaging scheme for wet deposition based on relative humidities. The same major conclusion is obtained for all the three different radioactive isotopes and using two different deposition measurement databases. Large differences are seen in the results obtained by using the two different parameterizations of wet deposition based on precipitation rates and relative humidities, respectively. The parameterization based on subgrid-scale averaging is, in all cases, performing better than the parameterization based on precipitation rates. This indicates that the in-cloud scavenging process is more important than the below cloud scavenging process for the submicron particles and that the precipitation rates are

  18. Use of wet-laid techniques to form flax-polypropylene nonwovens as base substrates for eco-friendly composites by using hot-press molding

    OpenAIRE

    Fages, Eduardo; GIRONÉS BERNABÉ, SAGRARIO; Sánchez Nacher, Lourdes; García Sanoguera, David; Balart Gimeno, Rafael Antonio

    2012-01-01

    The wet-laid process with flax (base) and polypropylene (binder) fibers has been used to obtain nonwovens for further processing by hot-press molding. Mechanical characterization of nonwovens has revealed that slight anisotropy is obtained with the wet-laid process as better tensile strength is obtained in the preferential deposition direction. The thermo-bonding process provides good cohesion to nonwovens, which is critical for further handling/shaping by hot-press molding. Flax:PP composite...

  19. Monitoring of Wet Snow and Accumulations at High Alpine Glaciers Using Radar Technologies

    Science.gov (United States)

    Wendleder, A.; Heilig, A.; Schmitt, A.; Mayer, C.

    2015-04-01

    Conventional studies to assess the annual mass balance for glaciers rely on single point observations in combination with model and interpolation approaches. Just recently, airborne and spaceborne data is used to support such mass balance determinations. Here, we present an approach to map temporal changes of the snow cover in glaciated regions of Tyrol, Austria, using SAR-based satellite data. Two dual-polarized SAR images are acquired on 22 and 24 September 2014. As X and C-band reveal different backscattering properties of snow, both TerraSAR-X and RADARSAT-2 images are analysed and compared to ground truth data. Through application of filter functions and processing steps containing a Kennaugh decomposition, ortho-rectification, radiometric enhancement and normalization, we were able to distinguish between dry and wet parts of the snow surface. The analyses reveal that the wet-snow can be unambiguously classified by applying a threshold of -11 dB. Bare ice at the surface or a dry snowpack does not appear in radar data with such low backscatter values. From the temporal shift of wet-snow, a discrimination of accumulation areas on glaciers is possible for specific observation dates. Such data can reveal a periodic monitoring of glaciers with high spatial coverage independent from weather or glacier conditions.

  20. Chemical solution deposition techniques for epitaxial growth of complex oxides

    NARCIS (Netherlands)

    ten Elshof, Johan E.; Koster, G.; Huijben, Mark; Rijnders, G.

    2015-01-01

    The chemical solution deposition (CSD) process is a wet-chemical process that is employed to fabricate a wide variety of amorphous and crystalline oxide thin films. This chapter describes the typical steps in a CSD process and their influence on the final microstructure and properties of films, and

  1. Atmospheric heavy metal deposition in the Copenhagen area

    DEFF Research Database (Denmark)

    Andersen, Allan; Hovmand, Mads Frederik; Johnsen, Ib

    1978-01-01

    Atmospheric dry and wet deposition (bulk precipitation) of the heavy metals Cu, Pb, Zn, Ni, V and Fe over the Copenhagen area was measured by sampling in plastic funnels from 17 stations during a twelve-month period. Epigeic bryophytes from 100 stations in the area were analysed for the heavy met...

  2. Wetting, Solubility and Chemical Characteristics of Plasma-Polymerized 1-Isopropyl-4-Methyl-1,4-Cyclohexadiene Thin Films

    Directory of Open Access Journals (Sweden)

    Jakaria Ahmad

    2014-07-01

    Full Text Available Investigations on the wetting, solubility and chemical composition of plasma polymer thin films provide an insight into the feasibility of implementing these polymeric materials in organic electronics, particularly where wet solution processing is involved. In this study, thin films were prepared from 1-isopropyl-4-methyl-1,4-cyclohexadiene (γ-Terpinene using radio frequency (RF plasma polymerization. FTIR showed the polymers to be structurally dissimilar to the original monomer and highly cross-linked, where the loss of original functional groups and the degree of cross-linking increased with deposition power. The polymer surfaces were hydrocarbon-rich, with oxygen present in the form of O–H and C=O functional groups. The oxygen content decreased with deposition power, with films becoming more hydrophobic and, thus, less wettable. The advancing and receding contact angles were investigated, and the water advancing contact angle was found to increase from 63.14° to 73.53° for thin films prepared with an RF power of 10 W to 75 W. The wetting envelopes for the surfaces were constructed to enable the prediction of the surfaces’ wettability for other solvents. The effect of roughness on the wetting behaviour of the films was insignificant. The polymers were determined to resist solubilization in solvents commonly used in the deposition of organic semiconducting layers, including chloroform and chlorobenzene, with higher stability observed in films fabricated at higher RF power.

  3. Critical Casimir forces and anomalous wetting

    Indian Academy of Sciences (India)

    Laboratoire de Physique Statistique de l´Ecole Normale Supérieure, associé au CNRS et aux Universités Paris 6 et 7, 24 rue Lhomond, 75231 Paris Cedex 05, France. E-mail: balibar@lps.ens.fr. Abstract. We present a review of critical Casimir forces in connection with successive experiments on wetting near the critical ...

  4. Making Activated Carbon by Wet Pressurized Pyrolysis

    Science.gov (United States)

    Fisher, John W.; Pisharody, Suresh; Wignarajah, K.; Moran, Mark

    2006-01-01

    A wet pressurized pyrolysis (wet carbonization) process has been invented as a means of producing activated carbon from a wide variety of inedible biomass consisting principally of plant wastes. The principal intended use of this activated carbon is room-temperature adsorption of pollutant gases from cooled incinerator exhaust streams. Activated carbon is highly porous and has a large surface area. The surface area depends strongly on the raw material and the production process. Coconut shells and bituminous coal are the primary raw materials that, until now, were converted into activated carbon of commercially acceptable quality by use of traditional production processes that involve activation by use of steam or carbon dioxide. In the wet pressurized pyrolysis process, the plant material is subjected to high pressure and temperature in an aqueous medium in the absence of oxygen for a specified amount of time to break carbon-oxygen bonds in the organic material and modify the structure of the material to obtain large surface area. Plant materials that have been used in demonstrations of the process include inedible parts of wheat, rice, potato, soybean, and tomato plants. The raw plant material is ground and mixed with a specified proportion of water. The mixture is placed in a stirred autoclave, wherein it is pyrolized at a temperature between 450 and 590 F (approximately between 230 and 310 C) and a pressure between 1 and 1.4 kpsi (approximately between 7 and 10 MPa) for a time between 5 minutes and 1 hour. The solid fraction remaining after wet carbonization is dried, then activated at a temperature of 500 F (260 C) in nitrogen gas. The activated carbon thus produced is comparable to commercial activated carbon. It can be used to adsorb oxides of sulfur, oxides of nitrogen, and trace amounts of hydrocarbons, any or all of which can be present in flue gas. Alternatively, the dried solid fraction can be used, even without the activation treatment, to absorb

  5. Wetting and phase separation at surfaces

    Indian Academy of Sciences (India)

    comparable to the RHS of figure 1. The averaging yields ψav(z, t) ≃ ψ0 = 0 in the bulk, where the phase-separation profiles are randomly oriented. However, a systematic behavior is seen at the surface. The wetting profiles are characterized by the zero-crossings of ψav(z, t) − ψ0. We denote the first and second zeros as.

  6. Wet flue gas desulphurization and new fuels

    Energy Technology Data Exchange (ETDEWEB)

    Kiil, S.; Dam-Johansen, K.; Michelsen, M.L.

    1998-04-01

    This thesis describes experimental and theoretical investigations of wet flue gas desulphurization (FGD). A review of the current knowledge of the various rate determining steps in wet FDG plants is presented. The mechanism underlying the rate of dissolution of finely grained limestone particles was examined in a laboratory batch apparatus using acid titration. Three Danish limestones of different origin were tested. A transient, mass transport controlled, mathematical model was developed to describe the dissolution process. Model predictions were found to be qualitatively in good agreement with experimental data. Empirical correlations for the dimensionless mass transfer coefficients in a pilot plant (falling-film column) were determined. The presence of inert particles in the liquid phase was found to decrease the rate of gas phase mass transport with up to 15%, though the effect could not be correlated. A detailed model for a wet FGD pilot plant, based on the falling film principle, was developed. All important rate determining steps, absorption of SO{sub 2}, oxidation of HSO{sub 3}{sup -}, dissolution of limestone, and crystallisation of gypsum were included. Model predictions were compared to experimental data such as gas phase concentration profiles of SO{sub 2}, slurry pH-profiles, solids contents of slurry, liquid phase concentrations, and residual limestone in the gypsum. The possibility of co-firing straw and coal was investigated in a full-scale power plant. No effects on the overall performance of the wet FGD plant were observed, though laboratory experiments with fine dust and fly ash from the full-scale experiments showed a decrease in limestone reactivity. (EG) EFP-95. 45 refs.; Also ph.d. thesis of Soeren Kiil

  7. Study of polycaprolactone wet electrospinning process

    Directory of Open Access Journals (Sweden)

    E. Kostakova

    2014-08-01

    Full Text Available Wet electrospinning is a useful method for 3-dimensional structure control of nanofibrous materials. This innovative technology uses a liquid collector instead of the metal one commonly used for standard electrospinning. The article compares the internal structural features of polycaprolactone (PCL nanofibrous materials prepared by both technologies. We analyze the influence of different water/ethanol compositions used as a liquid collector on the morphology of the resultant polycaprolactone nanofibrous materials. Scanning electron micro-photographs have revealed a bimodal structure in the wet electrospun materials composed of micro and nanofibers uniformly distributed across the sample bulk. We have shown that the full-faced, twofold fiber distribution is due to the solvent composition and is induced and enhanced by increasing the ethanol weight ratio. Moreover, the comparison of fibrous layers morphology obtained by wet and dry spinning have revealed that beads that frequently appeared in dry spun materials are created by Plateau-Rayleigh instability of the fraction of thicker fibers. Theoretical conditions for spontaneous and complete immersion of cylindrical fibers into a liquid collector are also derived here.

  8. Bioinspired Dynamic Wetting on Multiple Fibers.

    Science.gov (United States)

    Wang, Pengwei; Bian, Ruixin; Meng, Qing'an; Liu, Huan; Jiang, Lei

    2017-10-12

    Natural fibers have versatile strategies for interacting with water media and better adapting to the local environment, and these strategies offer inspiration for the development of artificial functional fibers with diverse applications. Wetting on fibers is a dynamic liquid-moving process on/in fibrous systems with various patterns, and the process is normally driven by the structural gradient, chemical gradient, elasticity of a single fiber, or the synergistic effect of these factors in multiple fibers in an integrated system in which the spatial geometry of the fibers is involved. Compared with the directional liquid movement on a single fiber, wetting on multiple fibers in both the micro- and macroscales is particularly fascinating, with various performances, including directional liquid transport, controllable liquid transfer, efficient liquid encapsulation, and capillary-induced fibrous coalescence. Based on these properties, fibrous materials offer an alternative open system for liquid manipulation that is applicable to various functional liquid materials. Here, recent achievements in bioinspired dynamic wetting on multiple fibers are highlighted, and perspectives on future directions are presented. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Cost estimation for advanced wet MOX plant

    Energy Technology Data Exchange (ETDEWEB)

    Kamiya, Masahito; Kojima, Hisao [Power Reactor and Nuclear Fuel Development Corp., Tokai, Ibaraki (Japan). Tokai Works

    1997-12-01

    PNC proposes a design concept of an advanced wet MOX plant based on low-level decontamination reprocessing plant and a simple fuel fabrication method. It significantly changes the boundary condition for design of reprocessing, fuel fabrication and reactor to alter the wet MOX cycle into a convenient form as simple as that of metal fuel cycle. According to the concept, the reprocessing process is substantially simplified by holding the decontamination level low, so that both reprocessing and fabrication processes can be installed in a single facility utilizing common utilities including a liquid waste processing facility. This report summarizes the results of the conceptual design of the plant and cost evaluation. Construction costs were estimated for the current plant constructed by means of the current technology, for the standard plant based on the improved technology of high-level decontamination cycle, and for the advanced plant based on the wet MOX cycle concept. It was concluded then that the construction costs in unit of the cost of the current plant were evaluated to be 0.60 for the standard plant (handling capacity 50 t/y) and 0.66 or 0.50 for the advanced plant (handling capacity 100 t/y or 50 t/y). (H. Baba)

  10. Florida's wet weather demonstration project : final report, January 2009.

    Science.gov (United States)

    2008-11-01

    The Florida Department of Transportation (FDOT) established a wet-weather pavement marking demonstration project with goals to gather performance data, evaluate various wet-weather marking systems, and develop a measurement protocol for measuring ret...

  11. Chemical vapor deposition coating for micromachines

    Energy Technology Data Exchange (ETDEWEB)

    MANI,SEETHAMBAL S.; FLEMING,JAMES G.; SNIEGOWSKI,JEFFRY J.; DE BOER,MAARTEN P.; IRWIN,LAWRENCE W.; WALRAVEN,JEREMY A.; TANNER,DANELLE M.; DUGGER,MICHAEL T.

    2000-04-21

    Two major problems associated with Si-based MEMS devices are stiction and wear. Surface modifications are needed to reduce both adhesion and friction in micromechanical structures to solve these problems. In this paper, the authors will present a process used to selectively coat MEMS devices with tungsten using a CVD (Chemical Vapor Deposition) process. The selective W deposition process results in a very conformal coating and can potentially solve both stiction and wear problems confronting MEMS processing. The selective deposition of tungsten is accomplished through silicon reduction of WF{sub 6}, which results in a self-limiting reaction. The selective deposition of W only on polysilicon surfaces prevents electrical shorts. Further, the self-limiting nature of this selective W deposition process ensures the consistency necessary for process control. Selective tungsten is deposited after the removal of the sacrificial oxides to minimize process integration problems. This tungsten coating adheres well and is hard and conducting, requirements for device performance. Furthermore, since the deposited tungsten infiltrates under adhered silicon parts and the volume of W deposited is less than the amount of Si consumed, it appears to be possible to release stuck parts that are contacted over small areas such as dimples. Results from tungsten deposition on MEMS structures with dimples will be presented. The effect of wet and vapor phase cleanings prior to the deposition will be discussed along with other process details. The W coating improved wear by orders of magnitude compared to uncoated parts. Tungsten CVD is used in the integrated-circuit industry, which makes this approach manufacturable.

  12. Heat removal (wetting, heat transfer, T/H, secondary circuit, code validation etc.)

    Energy Technology Data Exchange (ETDEWEB)

    Dury, T.; Siman-Tov, M.

    1996-06-01

    This working group provided a comprehensive list of feasibility and uncertainty issues. Most of the issues seem to fall into the `needed but can be worked out` category. They feel these can be worked out as the project develops. A few issues can be considered critical or feasibility issues (that must be proven to be feasible). Those include: (1) Thermal shock and its mitigation (>1 MW); how to inject the He bubbles (if used) - back pressure into He lines - mercury traces in He lines; how to maintain proper bubble distribution and size (static and dynamic; if used); vibrations and fatigue (dynamic); possibility of cavitation from thermal shock. (2) Wetting and/or non-wetting of mercury on containment walls with or without gases and its effect on heat transfer (and materials). (3) Prediction capabilities in the CFD code; bubbles behavior in mercury (if used) - cross stream turbulence (ESS only) - wetting/non-wetting effects. (4) Cooling of beam `windows`; concentration of local heat deposition at center, especially if beam is of parabolic profile.

  13. Interplay of wetting and phase separation at surfaces

    Science.gov (United States)

    Puri, Sanjay

    2007-10-01

    We review our understanding of surface-directed spinodal decomposition (SDSD), i.e., the interplay of wetting and phase separation in an unstable AB mixture placed in contact with a wetting surface. In this context, we present results for two problems, viz., SDSD in a semi-infinite geometry with a completely wet surface; and SDSD in a thin-film geometry with partially wet surfaces.

  14. A new remote optical wetness sensor and its applications

    NARCIS (Netherlands)

    Heusinkveld, B.G.; Berkowicz, S.M.; Jacobs, A.F.G.; Hillen, W.C.A.M.; Holtslag, A.A.M.

    2008-01-01

    An optical wetness sensor (OWS) was developed for continuous surface wetness measurements. The sensor is an all-weather instrument that does not interfere with the surface wetting and drying process and is unaffected by solar radiation. It is equipped with its own light source with which it can scan

  15. Characteristics of wet work in the cleaning industry

    NARCIS (Netherlands)

    Jungbauer, F H W; Van Der Harst, J J; Schuttelaar, M L; Groothoff, J W; Coenraads, P J

    Wet work is the main cause of occupational contact dermatitis in the cleaning industry. Dermatologists and occupational physicians need to base their primary and secondary prevention for workers in the cleaning industry on the characteristics of wet work exposures. We quantified the burden of wet

  16. Influence of the forest canopy on total and methyl mercury deposition in the boreal forest

    Science.gov (United States)

    E.L. Witt; R.K. Kolka; E.A. Nater; T.R. Wickman

    2009-01-01

    Atmospheric mercury deposition by wet and dry processes contributes mercury to terrestrial and aquatic systems. Factors influencing the amount of mercury deposited to boreal forests were identified in this study. Throughfall and open canopy precipitation samples were collected in 2005 and 2006 using passive precipitation collectors from pristine sites located across...

  17. Deposit model for volcanogenic uranium deposits

    Science.gov (United States)

    Breit, George N.; Hall, Susan M.

    2011-01-01

    Volcanism is a major contributor to the formation of important uranium deposits both close to centers of eruption and more distal as a result of deposition of ash with leachable uranium. Hydrothermal fluids that are driven by magmatic heat proximal to some volcanic centers directly form some deposits. These fluids leach uranium from U-bearing silicic volcanic rocks and concentrate it at sites of deposition within veins, stockworks, breccias, volcaniclastic rocks, and lacustrine caldera sediments. The volcanogenic uranium deposit model presented here summarizes attributes of those deposits and follows the focus of the International Atomic Energy Agency caldera-hosted uranium deposit model. Although inferred by some to have a volcanic component to their origin, iron oxide-copper-gold deposits with economically recoverable uranium contents are not considered in this model.

  18. Survival of Trichomonas vaginalis in wet preparation and on wet mount.

    Science.gov (United States)

    Stoner, Kevin A; Rabe, Lorna K; Meyn, Leslie A; Hillier, Sharon L

    2013-09-01

    Microscopy is an insensitive method for detection of Trichomonas vaginalis, but is widely used because it is both rapid and inexpensive. Diagnosis of trichomoniasis by microscopy requires that motile forms be identified in vaginal fluid samples. However, microscopy cannot always be performed immediately after sample collection. The objective of this study was to assess the impact of sample storage at room temperature on trichomonad motility. Vaginal swab samples from 77 women positive for T vaginalis infection were collected to determine the impact of storage on wet preparations (swabs in plastic tubes with saline) and wet mounts (samples placed onto a glass slide with a coverslip). Samples were read at 400× every 30 min for the first hour and then once per hour thereafter until there were no motile trichomonads observed. For wet preparations, motility was 100% at 30 min, 99% at 60 min and decreased by 3%-15% each subsequent hour, with samples having a lower density of trichomonads losing motility more quickly. Trichomonad motility diminished more rapidly in wet mounts compared with wet preparations, with a 20% decrement in motility in 60 min. These data suggest that vaginal fluid samples for diagnosis of trichomoniasis should be stored in saline rather than on microscope slides until they are examined under the microscope and samples should be evaluated by microscopy within an hour of collection. These findings also suggest that clinical sites which cannot perform microscopy within 1 h of sample collection should consider the use of other diagnostic tests.

  19. Fluvial Tufa Evidence of Late Pleistocene Wet Intervals from Santa Barbara, Southern California

    Science.gov (United States)

    Ibarra, Y.; Corsetti, F. A.; Feakins, S. J.; Rhodes, E. J.; Kirby, M. E.

    2014-12-01

    Past pluvials in the western United States provide valuable context for understanding regional hydroclimate variability. Here we report evidence of conditions substantially wetter than today from fluvial tufa deposits located near Zaca Lake, Santa Barbara County, California that have been dated by radiocarbon (14C) and Infra-Red Stimulated Luminescence (IRSL). Two successions of tufa deposition occur within a small catchment that drains Miocene Monterey Formation bedrock: 1) a fluvial deposit (0-0.5 m thick, 200 m in extent) that formed along a narrow valley below a modern spring, and 2) a perched deposit about 10 m higher (2 m thick, 15 m in extent). IRSL and radiocarbon dating of the perched carbonates suggests at least two episodes of carbonate growth: one at 19.4 ± 2.4 (1σ) through 17.8 ± 2.8 (1σ) ka and another at 11.9 ± 1.5 (1σ) ka verified with a charcoal 14C age of 10.95 ± 0.12 (2σ) cal ka BP. The relationship between the perched and fluvial spring deposits is inferred to represent a drop in the water table of more than 10 m associated with a transition from a wet climate in the late glacial to a dry Holocene today. The wet period indicated by tufa growth between 19.4 and 17.8 ka is relatively consistent with other California climate records both north and south of Zaca Lake. However, tufa growth ca. 12 to 11 ka demonstrates wet conditions occurred as far south as Zaca Lake during the Younger Dryas event, in contrast to climate records farther south in Lake Elsinore indicating persistently dry conditions through this interval. A small shift north in the average position of the winter season storm track could explain wet winters at Zaca while at the same time generating dry winters at Lake Elsinore, 275 km southwest of Zaca. If true, these data indicate that rather small latitudinal shifts in the average winter season storm track can produce large changes in regional hydroclimate.

  20. Semantics of Temporal Models with Multiple Temporal Dimensions

    DEFF Research Database (Denmark)

    Kraft, Peter; Sørensen, Jens Otto

    Semantics of temporal models with multi temporal dimensions are examined progressing from non-temporal models unto uni-temporal, and further unto bi- and tri-temporal models. An example of a uni-temporal model is the valid time model, an example of a bi-temporal model is the valid time/transactio...

  1. Viscoelastic and poroelastic effects in the wetting dynamics of soft gels by liquids

    Science.gov (United States)

    Limat, Laurent; Dervaux, Julien; Roche, Matthieu; Zhao, Menghua; Narita, Tetsuharu; Lequeux, Francois

    2017-11-01

    We have developed experiments and modeling of elastowetting dynamics on soft gels. First, wetting is very sensitive to the thickness of the gel, when deposited on a rigid basis. We reconsidered Long et al. approach, and extended it to finite depth. This yields a new scaling law, at low thickness, for dynamic contact angle, in very good agreement with experiment but not consistent with recent approachs assuming Neuman triangle to hold even in the dynamics. In a second step, we examined solvent migration in the bulk of the gel, and showed that poroelasticity is an essential ingredient to understand old unsolved issues (hysteresis on elastomers by Extrand and Kumagai), as well as recent puzzling measurements (long life footprints left by drops). Our calculations lead to ridges at the contact lines evolving logarithmically with time, with a very strong infuence on wetting properties of soft materials, and with possible applications to biophysics.

  2. "Wetting enhancer" pullulan coating for antifog packaging applications.

    Science.gov (United States)

    Introzzi, Laura; Fuentes-Alventosa, José María; Cozzolino, Carlo A; Trabattoni, Silvia; Tavazzi, Silvia; Bianchi, Claudia L; Schiraldi, Alberto; Piergiovanni, Luciano; Farris, Stefano

    2012-07-25

    A new antifog coating made of pullulan is described in this work. The antifog properties are discussed in terms of wettability, surface chemistry/morphology, and by quantitative assessment of the optical properties (haze and transparency) before and after fog formation. The work also presents the results of antifog tests simulating the typical storage conditions of fresh foods. In these tests, the antifog efficiency of the pullulan coating was compared with that of two commercial antifog films, whereas an untreated low-density polyethylene (LDPE) film was used as a reference. The obtained results revealed that the pullulan coating behaved as a "wetting enhancer", mainly due to the low water contact angle (∼24°), which in turn can be ascribed to the inherent hydrophilic nature of this polysaccharide, as also suggested by the X-ray photoelectron spectroscopy experiments. Unlike the case of untreated LDPE and commercial antifog samples, no discrete water formations (i.e., droplets or stains) were observed on the antifog pullulan coating on refrigeration during testing. Rather, an invisible, continuous and thin layer of water occurred on the biopolymer surface, which was the reason for the unaltered haze and increased transparency, with the layer of water possibly behaving as an antireflection layer. As confirmed by atomic force microscopy analysis, the even deposition of the coating on the plastic substrate compared to the patchy surfacing of the antifog additives in the commercial films is another important factor dictating the best performance of the antifog pullulan coating.

  3. Surface Wrinkling on Polydimethylsiloxane Microspheres via Wet Surface Chemical Oxidation

    Science.gov (United States)

    Yin, Jian; Han, Xue; Cao, Yanping; Lu, Conghua

    2014-07-01

    Here we introduce a simple low-cost yet robust method to realize spontaneously wrinkled morphologies on spherical surfaces. It is based on surface chemical oxidation of aqueous-phase-synthesized polydimethylsiloxane (PDMS) microspheres in the mixed H2SO4/HNO3/H2O solution. Consequently, curvature and overstress-sensitive wrinkles including dimples and labyrinth patterns are successfully induced on the resulting oxidized PDMS microspheres. A power-law dependence of the wrinkling wavelength on the microsphere radius exists. The effects of experimental parameters on these tunable spherical wrinkles have been systematically investigated, when the microspheres are pre-deposited on a substrate. These parameters include the radius and modulus of microspheres, the mixed acid solution composition, the oxidation duration, and the water washing post-treatment. Meanwhile, the complicated chemical oxidation process has also been well studied by in-situ optical observation via the microsphere system, which represents an intractable issue in a planar system. Furthermore, we realize surface wrinkled topographies on the whole microspheres at a large scale, when microspheres are directly dispersed in the mixed acid solution for surface oxidation. These results indicate that the introduced wet surface chemical oxidation has the great potential to apply to other complicated curved surfaces for large-scale generation of well-defined wrinkling patterns, which endow the solids with desired physical properties.

  4. Wet oxidation processes for water pollution remediation

    OpenAIRE

    García Molina, Verónica

    2006-01-01

    The main objective of this work was to test the efficiency of wet oxidation processes when treating several types of aqueous wastes. On one side its performance for the abatement of chloro-organic aromatic toxic pollutants, such as 4-chlorophenol and 2,4-dichlorophenol has been studied. On the other hand, wastewater from pulp and paper mills, which has been reported to be an indirect source of entry of chlorophenols in the aquatic environment, has been investigated. More in detail, it has bee...

  5. Collapse of granular media subjected to wetting

    Directory of Open Access Journals (Sweden)

    El Korchi Fatima Zahra

    2017-01-01

    Full Text Available This paper focuses on the collapse of granular materials subjected to wetting action. For soils, the collapse potential depends on several parameters such as liquid limit, matric suction, compactness, initial water content and the amount of fine particles. The effect of grain size, which plays a key role in the rearrangement of grains, remains little studied and poorly understood. To investigate the capillary origin of the collapse phenomenon, we present an experimental study on macroscopic and local scales. Our results show the effect of grain size and water content on collapse.

  6. Even low to medium nitrogen deposition impacts vegetation of dry, coastal dunes around the Baltic Sea.

    Science.gov (United States)

    Remke, Eva; Brouwer, Emiel; Kooijman, Annemieke; Blindow, Irmgard; Esselink, Hans; Roelofs, Jan G M

    2009-03-01

    Coastal dunes around the Baltic Sea have received small amounts of atmospheric nitrogen and are rather pristine ecosystems in this respect. In 19 investigated dune sites the atmospheric wet nitrogen deposition is 3-8kg Nha(-1)yr(-1). The nitrogen content of Cladonia portentosa appeared to be a suitable biomonitor of these low to medium deposition levels. Comparison with EMEP-deposition data showed that Cladonia reflects the deposition history of the last 3-6 years. With increasing nitrogen load, we observed a shift from lichen-rich short grass vegetation towards species-poor vegetation dominated by the tall graminoid Carex arenaria. Plant species richness per field site, however, does not decrease directly with these low to medium N deposition loads, but with change in vegetation composition. Critical loads for acidic, dry coastal dunes might be lower than previously thought, in the range of 4-6kg Nha(-1)yr(-1) wet deposition.

  7. Dislocation density investigation on MOCVD-grown GaN epitaxial layers using wet and dry defect selective etching

    Science.gov (United States)

    Pandey, Akhilesh; Yadav, Brajesh S.; Rao, D. V. Sridhara; Kaur, Davinder; Kapoor, Ashok Kumar

    2016-06-01

    Results on the investigations of the dislocation etch pits in the GaN layers grown on sapphire substrate by metal organic chemical vapor deposition are revealed by wet chemical etching, and dry etching techniques are reported. The wet etching was carried out in molten KOH, and inductively coupled plasma (ICP) was used for dry etching. We show that ICP using dry etching and wet chemical etching using KOH solution under optimal conditions give values of dislocation density comparable to the one obtained from the high-resolution X-ray diffraction, atomic force microscopy and transmission electron microscopy investigations. Investigated threading dislocation density is in the order of ~109/cm2 using different techniques.

  8. Nitrogen emission and deposition budget in West and Central Africa

    Science.gov (United States)

    Galy-Lacaux, C.; Delon, C.

    2014-12-01

    Atmospheric nitrogen depends on land surface exchanges of nitrogen compounds. In Sub Saharan Africa, deposition and emission fluxes of nitrogen compounds are poorly quantified, and are likely to increase in the near future due to land use change and anthropogenic pressure. This work proposes an estimate of atmospheric N compounds budget in West and Central Africa, along an ecosystem transect, from dry savanna to wet savanna and forest, for years 2000-2007. The budget may be considered as a one point in time budget, to be included in long term studies as one of the first reference point for Sub Saharan Africa. Gaseous dry deposition fluxes are estimated by considering N compounds concentrations measured in the frame of the IDAF network (IGAC/DEBITS/AFrica) at the monthly scale and modeling of deposition velocities at the IDAF sites, taking into account the bi directional exchange of ammonia. Particulate dry deposition fluxes are calculated using the same inferential method. Wet deposition fluxes are calculated from measurements of ammonium and nitrate chemical content in precipitations at the IDAF sites combined with the annual rainfall amount. In terms of emission, biogenic NO emissions are simulated at each IDAF site with a surface model coupled to an emission module elaborated from an artificial neural network equation. Ammonia emissions from volatilization are calculated from literature data on livestock quantity in each country and N content in manure. NOx and NH3 emission from biomass burning and domestic fires are estimated from satellite data and emission factors. The total budget shows that emission sources of nitrogen compounds are in equilibrium with deposition fluxes in dry and wet savannas, with respectively 7.40 (±1.90) deposited and 9.01 (±3.44) kgN ha-1 yr-1 emitted in dry savanna, 8.38 (±2.04) kgN ha-1 yr-1 deposited and 9.60 (±0.69) kgN ha-1 yr-1 emitted in wet savanna. In forested ecosystems, the total budget is dominated by wet plus dry

  9. A wetting and drying scheme for ROMS

    Science.gov (United States)

    Warner, John C.; Defne, Zafer; Haas, Kevin; Arango, Hernan G.

    2013-01-01

    The processes of wetting and drying have many important physical and biological impacts on shallow water systems. Inundation and dewatering effects on coastal mud flats and beaches occur on various time scales ranging from storm surge, periodic rise and fall of the tide, to infragravity wave motions. To correctly simulate these physical processes with a numerical model requires the capability of the computational cells to become inundated and dewatered. In this paper, we describe a method for wetting and drying based on an approach consistent with a cell-face blocking algorithm. The method allows water to always flow into any cell, but prevents outflow from a cell when the total depth in that cell is less than a user defined critical value. We describe the method, the implementation into the three-dimensional Regional Oceanographic Modeling System (ROMS), and exhibit the new capability under three scenarios: an analytical expression for shallow water flows, a dam break test case, and a realistic application to part of a wetland area along the Georgia Coast, USA.

  10. Wet paper codes with improved embedding efficiency

    Science.gov (United States)

    Fridrich, Jessica; Goljan, Miroslav; Soukal, David

    2006-02-01

    Construction of steganographic schemes in which the sender and the receiver do not share the knowledge about the location of embedding changes requires wet paper codes. Steganography with non-shared selection channels empowers the sender as now he is able to embed secret data by utilizing arbitrary side information, including a high-resolution version of the cover object (perturbed quantization steganography), local properties of the cover (adaptive steganography), and even pure randomness, e.g., coin flipping, for public key steganography. In this paper, we propose a new approach to wet paper codes using random linear codes of small codimension that at the same time improves the embedding efficiency-the number of message bits embedded per embedding change. We describe a practical algorithm, test its performance experimentally, and compare the results to theoretically achievable bounds. We point out an interesting ripple phenomenon that should be taken into account by practitioners. The proposed coding method can be modularly combined with most steganographic schemes to allow them to use non-shared selection channels and, at the same time, improve their security by decreasing the number of embedding changes.

  11. Further progress in watermark evaluation testbed (WET)

    Science.gov (United States)

    Kim, Hyung C.; Lin, Eugene T.; Guitart, Oriol; Delp, Edward J., III

    2005-03-01

    While Digital Watermarking has received much attention in recent years, it is still a relatively young technology. There are few accepted tools/metrics that can be used to evaluate the suitability of a watermarking technique for a specific application. This lack of a universally adopted set of metrics/methods has motivated us to develop a web-based digital watermark evaluation system called the Watermark Evaluation Testbed or WET. There have been more improvements over the first version of WET. We implemented batch mode with a queue that allows for user submitted jobs. In addition to StirMark 3.1 as an attack module, we added attack modules based on StirMark 4.0. For a new image fidelity measure, we evaluate conditional entropy as an image fidelity measure for different watermarking algorithms and different attacks. Also, we show the results of curve fitting the Receiver Operating Characteristic (ROC) analysis data using the Parzen window density estimation. The curve fits the data closely while having only two parameters to estimate.

  12. The investigation of the mechanism of sulfur deposition in Asia

    Science.gov (United States)

    Xu, Yiwen

    1998-11-01

    The sulfur pollution and long range transport in Asia is becoming an important issue due to the significant increase in energy use. There is no international treaty to limit the transport of sulfur between countries. The development of RAINS-ASIA software provides a tool to investigate the acidification in southeast Asia, and for policy makers to assess the consequences of emission strategies to control acidification in the future. The Acid Deposition Module (ADM) is the key element in calculating sulfur deposition. It was developed from 'The Branching Atmospheric Trajectory Model' by the National Oceanic and Atmospheric Administration. The first part of this study is to modify the model to include sulfur chemistry, dry deposition with deposition velocity over two land types, sea and land, and below cloud scavenging. The modified model is used to study the source-receptor relationship in Asian 94 regions, 23 countries. The second part of this study is to modify the model with more detailed sulfur deposition mechanism. The modifications include sulfur gas phase and aqueous phase chemistry, and below cloud and in cloud scavenging. The establishment of the Dry Deposition Module (DDM) provides monthly averaged dry deposition velocity over 9 land types. The ADM predicts sulfur concentrations and sulfate wet deposition within an error factor of two. The calibration and verification were performed by running August and February 1990 with annual ground and elevated emission sources estimated by the RAINS-ASIA emission module. The working domain is from 20 South to 50 North, 39 East to 154 East. The comparison was made by using the two months Japan CRIEPI observed concentrations and sulfate wet deposition. The results show that the concentration of SO2 and sulfate in winter is relatively higher. In contrast to Europe and North America, sulfate pollution is heavier than SO2 in Asia. The high sulfate concentrations ace distributed in eastern China, Korea and Japan, with an

  13. WetLab-2: Wet Lab RNA SmartCycler Providing PCR Capability on ISS

    Science.gov (United States)

    Parra, Macarena; Schonfeld, Julie

    2015-01-01

    The WetLab-2 system will provide sample preparation and qRT-PCR analysis on-board the ISS, a capability to enable using the ISS as a real laboratory. The system will be validated on SpX-7, and is planned for its first PI use on SpX-9.

  14. Doubly Reentrant Cavities Prevent Catastrophic Wetting Transitions on Intrinsically Wetting Surfaces

    KAUST Repository

    Domingues, Eddy

    2017-06-05

    Omniphobic surfaces, i.e. which repel all known liquids, have proven of value in applications ranging from membrane distillation to underwater drag reduction. A limitation of currently employed omniphobic surfaces is that they rely on perfluorinated coatings, increasing cost and environmental impact, and preventing applications in harsh environments. There is, thus, a keen interest in rendering conventional materials, such as plastics, omniphobic by micro/nano-texturing rather than via chemical make-up, with notable success having been achieved for silica surfaces with doubly reentrant micropillars. However, we found a critical limitation of microtextures comprising of pillars that they undergo catastrophic wetting transitions (apparent contact angles, θr → 0° from θr > 90°) in the presence of localized physical damages/defects or on immersion in wetting liquids. In response, a doubly reentrant cavity microtexture is introduced, which can prevent catastrophic wetting transitions in the presence of localized structural damage/defects or on immersion in wetting liquids. Remarkably, our silica surfaces with doubly reentrant cavities could exhibited apparent contact angles, θr ≈ 135° for mineral oil, where the intrinsic contact angle, θo ≈ 20°. Further, when immersed in mineral oil or water, doubly reentrant microtextures in silica (θo ≈ 40° for water) were not penetrated even after several days of investigation. Thus, microtextures comprising of doubly reentrant cavities might enable applications of conventional materials without chemical modifications, especially in scenarios that are prone to localized damages or immersion in wetting liquids, e.g. hydrodynamic drag reduction and membrane distillation.

  15. Atmospheric deposition in relation to acidification and eutrophication

    Energy Technology Data Exchange (ETDEWEB)

    Erisman, J.W.; Draaijers, G.P.J. [National Institute of Public Health and the Environment, Bilthoven (Netherlands). Air Research Laboratory

    1995-12-31

    This book was written to collect the results of research in the Netherlands and other countries on atmospheric deposition and critical loads. It covers: the history of atmospheric deposition research in the Netherlands and elsewhere; emission, transformation and transport of nitrogen and sulphur compounds and their atmospheric chemistry; wet, dry, cloud and fog deposition processes and measurement; measurement results for NO{sub x}, HNO{sub x}, PAN, NH{sub 3}, HCl, particles and meteorites; deposition modelling in the Netherlands and elsewhere, including historical variation; evaluation of deposition estimates for SO{sub 2}, soil loads, and DEADM and EDACS results. Three case studies are given from Utrechtese Heuvelrug forest; the Speulder forest; and the Elspeetsche Veld. Impacts on forests and other vegetation are given. 625 refs., 118 figs., 69 tabs.

  16. Observations of atmospheric chemical deposition to high Arctic snow

    Science.gov (United States)

    Macdonald, Katrina M.; Sharma, Sangeeta; Toom, Desiree; Chivulescu, Alina; Hanna, Sarah; Bertram, Allan K.; Platt, Andrew; Elsasser, Mike; Huang, Lin; Tarasick, David; Chellman, Nathan; McConnell, Joseph R.; Bozem, Heiko; Kunkel, Daniel; Duan Lei, Ying; Evans, Greg J.; Abbatt, Jonathan P. D.

    2017-05-01

    Rapidly rising temperatures and loss of snow and ice cover have demonstrated the unique vulnerability of the high Arctic to climate change. There are major uncertainties in modelling the chemical depositional and scavenging processes of Arctic snow. To that end, fresh snow samples collected on average every 4 days at Alert, Nunavut, from September 2014 to June 2015 were analyzed for black carbon, major ions, and metals, and their concentrations and fluxes were reported. Comparison with simultaneous measurements of atmospheric aerosol mass loadings yields effective deposition velocities that encompass all processes by which the atmospheric species are transferred to the snow. It is inferred from these values that dry deposition is the dominant removal mechanism for several compounds over the winter while wet deposition increased in importance in the fall and spring, possibly due to enhanced scavenging by mixed-phase clouds. Black carbon aerosol was the least efficiently deposited species to the snow.

  17. Mapping of depositional and non-depositional areas in Salinas, California streams with concurrent pyrethroid and benthic macroinvertebrate assessments.

    Science.gov (United States)

    Hall, Lenwood W; Anderson, Ronald D; Killen, William D

    2013-01-01

    This study used sediment mapping to determine the spatial extent of depositional and non-depositional areas in the wetted stream bed of four urban streams in Salinas, California. After the stream mapping was completed, 8 pyrethroids were analytically measured from randomly selected sites in 12 depositional and 12 non-depositional areas in the four Salinas streams. Benthic macroinvertebrate samples were collected and identified from depositional and non-depositional areas where pyrethroids were measured. In addition, physical habitat was also evaluated at each site where benthic communities were collected. Based on a random sampling design, 24 % of the 96 sediment sampling sites in the Salinas streams were classified as predominately depositional areas. Mean total pyrethroid concentrations were approximately 2× to 61× times higher in depositional areas of the Salinas streams when compared to non-depositional areas. Physical habitat scores from the 12 depositional and 12 non-depositional areas in the Salinas stream sites were extremely low compared with other California streams thus demonstrating that impaired physical habitat is a critical stressor in these streams. Approximately 6,300 individual macroinvertebrates were picked and identified from 70 taxa from the 24 Salinas stream sites. The most dominant taxa collected were all considered tolerant of environmental stressors and dominant taxa from both depositional and non-deposition areas were similar. Ten different benthic metrics for the Salinas streams were similar for the depositional areas, where pyrethroid concentrations consistently exceeded laboratory based toxicity thresholds, and non-depositional areas where pyrethroid concentrations were much lower. These results suggest that factors other than pyrethroids are responsible for impacting resident benthic communities in these urban Salinas streams.

  18. Modelling deposition and air concentration of reduced nitrogen in Poland and sensitivity to variability in annual meteorology.

    Science.gov (United States)

    Kryza, Maciej; Dore, Anthony J; Błaś, Marek; Sobik, Mieczysław

    2011-04-01

    The relative contribution of reduced nitrogen to acid and eutrophic deposition in Europe has increased recently as a result of European policies which have been successful in reducing SO(2) and NO(x) emissions but have had smaller impacts on ammonia (NH(3)) emissions. In this paper the Fine Resolution Atmospheric Multi-pollutant Exchange (FRAME) model was used to calculate the spatial patterns of annual average ammonia and ammonium (NH(4)(+)) air concentrations and reduced nitrogen (NH(x)) dry and wet deposition with a 5 km × 5 km grid for years 2002-2005. The modelled air concentrations of NH(3) and dry deposition of NH(x) show similar spatial patterns for all years considered. The largest year to year changes were found for wet deposition, which vary considerably with precipitation amount. The FRAME modelled air concentrations and wet deposition are in reasonable agreement with available measurements (Pearson's correlation coefficients above 0.6 for years 2002-2005), and with spatial patterns of concentrations and deposition of NH(x) reported with the EMEP results, but show larger spatial gradients. The error statistics show that the FRAME model results are in better agreement with measurements if compared with EMEP estimates. The differences in deposition budgets calculated with FRAME and EMEP do not exceed 17% for wet and 6% for dry deposition, with FRAME estimates higher than for EMEP wet deposition for modelled period and lower or equal for dry deposition. The FRAME estimates of wet deposition budget are lower than the measurement-based values reported by the Chief Inspectorate of Environmental Protection of Poland, with the differences by approximately 3%. Up to 93% of dry and 53% of wet deposition of NH(x) in Poland originates from national sources. Over the western part of Poland and mountainous areas in the south, transboundary transport can contribute over 80% of total (dry + wet) NH(x) deposition. The spatial pattern of the relative contribution of

  19. Proteomic effects of wet cupping (Al-hijamah).

    Science.gov (United States)

    Almaiman, Amer A

    2018-01-01

    Wet cupping (Al-hijamah) is a therapeutic technique practiced worldwide as a part of the Unani system of medicine. It involves bloodletting from acupoints on a patient's skin to produce a therapeutic outcome. A thorough review of research articles on wet cupping with relevance to proteomics field that are indexed by Google Scholar, PubMed, and/or Science Direct databases was performed. Eight original research articles were summarized in this paper. Overall, wet cupping did not have a significant effect on C-reactive protein, Hsp-27, sister chromatid exchanges, and cell replication index. In contrast, wet cupping was found to produce higher oxygen saturation, eliminate lactate from subcutaneous tissues, remove blood containing higher levels of malondialdehyde and nitric oxide, and produce higher activity of myeloperoxidase. The proteomic effects of wet cupping therapy have not been adequately investigated. Thus, future studies on wet cupping that use systemic and sound protocols to avoid bias should be conducted.

  20. Wet-cupping removes oxidants and decreases oxidative stress.

    Science.gov (United States)

    Tagil, Suleyman Murat; Celik, Huseyin Tugrul; Ciftci, Sefa; Kazanci, Fatmanur Hacievliyagil; Arslan, Muzeyyen; Erdamar, Nazan; Kesik, Yunus; Erdamar, Husamettin; Dane, Senol

    2014-12-01

    Wet-cupping therapy is one of the oldest known medical techniques. Although it is widely used in various conditions such as acute\\chronic inflammation, infectious diseases, and immune system disorders, its mechanism of action is not fully known. In this study, we investigated the oxidative status as the first step to elucidate possible mechanisms of action of wet cupping. Wet cupping therapy is implemented to 31 healthy volunteers. Venous blood samples and Wet cupping blood samples were taken concurrently. Serum nitricoxide, malondialdehyde levels and activity of superoxide dismutase and myeloperoxidase were measured spectrophotometrically. Wet cupping blood had higher activity of myeloperoxidase, lower activity of superoxide dismutase, higher levels of malondialdehyde and nitricoxide compared to the venous blood. Wet cupping removes oxidants and decreases oxidative stress. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Tympanoplasty: does dry or wet temporalis fascia graft matter?

    Science.gov (United States)

    Singh, G B; Kumar, D; Aggarwal, K; Garg, S; Arora, R; Kumar, S

    2016-08-01

    To evaluate the success rate of dry and wet temporalis fascia grafts in type I underlay tympanoplasty. A prospective, randomised study was conducted. One hundred adult patients (males and females) with chronic suppurative otitis media (mucosal type) were divided into 2 groups of 50 each: one group underwent dry graft tympanoplasty and the other underwent wet graft tympanoplasty. Fibroblast count was calculated in dry and wet grafts. The dry graft and wet graft groups had overall surgical success rates of 82 and 90 per cent, respectively; this finding was not statistically significant. A statistically significant high fibroblast count was observed in wet grafts, but it did not correlate with surgical success. A dry or wet temporalis fascia graft does not influence the outcome of tympanoplasty type I.

  2. Wick wetting for water condensation systems

    Science.gov (United States)

    Hering, Susanne Vera; Spielman, Steven Russel; Lewis, Gregory Stephen; Kreisberg, Nathan Michael

    2017-04-04

    A system and method for particle enlargement with continuously wetted wicks includes a container into which a flow of particle-laden air is introduced in a laminar manner through an inlet and to an outlet. The container has a first section, a second section and a third section though which the particle-laden air flows between the inlet and the outlet. The temperature of the second section is warmer than that of the first section at the inlet and the third section at the outlet. In one embodiment, a continuous wick spanning an interior wall of the first second, second section and third section, said wick being capable of internally transporting liquid water along its length is provided.

  3. THERMAL TRANSFERS IN WET HYPERBARIC ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    Tamara STANCIU

    2014-05-01

    Full Text Available The heat losses of human body are greater in underwater environment than in dry, normal atmosphere, due to the great heat capacity of water. Body temperature of divers in immersion was studied taking into account the pressure the divers are subjected to. The theoretic equation that describes the total heat transfer- at both levels: skin and respiratory system- was established, considering conduction, convection and respiratory gas heating and humidification. The body temperature of the divers was measured in a series of dives at different depths of immersion, conducted in the wet simulator of the Diving Center, in Constanta. The experimental results were in good accordance with the temperature predicted by the mathematical model.

  4. BERYLLIUM MEASUREMENT IN COMMERCIALLY AVAILABLE WET WIPES

    Energy Technology Data Exchange (ETDEWEB)

    Youmans-Mcdonald, L.

    2011-02-18

    Analysis for beryllium by fluorescence is now an established method which is used in many government-run laboratories and commercial facilities. This study investigates the use of this technique using commercially available wet wipes. The fluorescence method is widely documented and has been approved as a standard test method by ASTM International and the National Institute for Occupational Safety and Health (NIOSH). The procedure involves dissolution of samples in aqueous ammonium bifluoride solution and then adding a small aliquot to a basic hydroxybenzoquinoline sulfonate fluorescent dye (Berylliant{trademark} Inc. Detection Solution Part No. CH-2) , and measuring the fluorescence. This method is specific to beryllium. This work explores the use of three different commercial wipes spiked with beryllium, as beryllium acetate or as beryllium oxide and subsequent analysis by optical fluorescence. The effect of possible interfering metals such as Fe, Ti and Pu in the wipe medium is also examined.

  5. Improved bitumen extraction using wet combustion

    Energy Technology Data Exchange (ETDEWEB)

    Wylie, I.; Hagen, D.; McGuire, A. [VAST Power Systems Inc., Elkhart, IN (United States)

    2007-07-01

    This presentation outlined the main concerns regarding the current combustion paradigm for steam assisted gravity drainage (SAGD) bitumen extraction and provided a solution that is more energy efficient with less environmental impact. SAGD operations currently use dry steam injection to deliver heat and reduce the viscosity bitumen, but this results in heat loss, restricted fuel choices, high water use and high emissions. Vast Power Systems Inc. has developed a wet flue gas known as VASTgas{sup TM} for efficient extraction. The downhole fluid has a much higher heat output and much lower emissions of nitrogen oxides, carbon monoxide and carbon dioxide. Other key advantages include net clean water from combustion and electricity as a by-product. This presentation also described the advantages of the VASThermogenerator{sup TM} for SAGD which solves some of the concerns regarding the combustion paradigm of mined bitumen and tailings pond purification. figs.

  6. Wet-Bulb-Globe Temperature Data Report

    Science.gov (United States)

    2015-03-01

    ARL‐SR‐0317 ● MAR 2015          US Army Research Laboratory      Wet‐ Bulb –Globe Temperature Data Report    by David P Sauter...originator.         ARL‐SR‐0317 ● MAR 2015      US Army Research Laboratory      Wet‐ Bulb –Globe Temperature Data Report    by David P Sauter...March 2015 2. REPORT TYPE  Special Report 3. DATES COVERED (From ‐ To)  11 Aug 2014–23 Aug 2014 4. TITLE AND SUBTITLE  Wet- Bulb –Globe Temperature

  7. Modeling the early stages of reactive wetting.

    Science.gov (United States)

    Wheeler, Daniel; Warren, James A; Boettinger, William J

    2010-11-01

    Recent experimental studies of molten metal droplets wetting high-temperature reactive substrates have established that the majority of triple-line motion occurs when inertial effects are dominant. In light of these studies, this paper investigates wetting and spreading on reactive substrates when inertial effects are dominant using a thermodynamically derived diffuse interface model of a binary three-phase material. The liquid-vapor transition is modeled using a van der Waals diffuse interface approach, while the solid-fluid transition is modeled using a phase field approach. The results from the simulations demonstrate an O(t(-1/2)) spreading rate during the inertial regime and oscillations in the triple-line position when the metal droplet transitions from inertial to diffusive spreading. It is found that the spreading extent is reduced by enhancing dissolution by manipulating the initial liquid composition. The results from the model exhibit good qualitative and quantitative agreement with a number of recent experimental studies of high-temperature droplet spreading, particularly experiments of copper droplets spreading on silicon substrates. Analysis of the numerical data from the model suggests that the extent and rate of spreading are regulated by the spreading coefficient calculated from a force balance based on a plausible definition of the instantaneous interface energies. A number of contemporary publications have discussed the likely dissipation mechanism in spreading droplets. Thus, we examine the dissipation mechanism using the entropy-production field and determine that dissipation primarily occurs in the locality of the triple-line region during the inertial stage but extends along the solid-liquid interface region during the diffusive stage.

  8. Bed wetting in school children of Karachi.

    Science.gov (United States)

    Mithani, Shoaib; Zaidi, Zafar

    2005-01-01

    To estimate the frequency of primary nocturnal enuresis (PNE) in Pakistani children and to examine the factors associated with it. A randomly selected cross-sectional study was conducted in five elementary schools, one in each of five districts of Karachi. The parents of 5000 children age between 3-13 years were asked to complete a questionnaire which included items about the frequency of daytime wetting and nocturnal enuresis, family history, urinary tract infection, parents and child's own concern about this problem and acquisition of treatments. Over all corrected response rate to the questionnaire was 69% (3395). Enuresis was present in 9.1% (308). There were 166 (53.9%) boys and 142 (46%) girls with a median age of 7 years. Only 54% (166) children sought help for their problem of which 26% consulted doctors, 16% visited homeopaths while 11% used hakeems and home remedies. Of the bed wetters, 30% were wet every night, 30% for more than three nights a week and 40% for less than three nights every week. Parents of 68.5% (211) children reported concern for the problem while 69.8% (215) children were also anxious about their enuresis. Among the concerned children group, 22% parents were not concerned about their child's problem. Family history of enuresis was present in 25.6% (79) children. The frequency of enuresis among the school going children in Karachi is 9.1% and is similar to that reported in European countries and other Asian countries including Korea and Taiwan. Enuresis causes concern to both parents and children, but only a small percentage of parents seek medical help for this problem.

  9. Pavement Marking Visibility Requirements During Wet Night Conditions

    OpenAIRE

    Gibbons, Ronald B. (Ronald Bruce)

    2006-01-01

    This study investigated the performance of pavement markings in wet night conditions. Typically, performance will decrease in wet conditions. The degradation is a result of flooding of the marking optics and a change in the optical media, thereby reducing retroreflectivity and the visibility distance. Several technologies are available to improve the visibility of markings under wet conditions. This study used four technologies and evaluated them in a dynamic situation. In the experiment, veh...

  10. Inductive Temporal Logic Programming

    OpenAIRE

    Kolter, Robert

    2009-01-01

    We study the extension of techniques from Inductive Logic Programming (ILP) to temporal logic programming languages. Therefore we present two temporal logic programming languages and analyse the learnability of programs from these languages from finite sets of examples. In first order temporal logic the following topics are analysed: - How can we characterize the denotational semantics of programs? - Which proof techniques are best suited? - How complex is the learning task? In propositional ...

  11. Modeling atmospheric deposition using a stochastic transport model

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, R.L.

    1999-12-17

    An advanced stochastic transport model has been modified to include the removal mechanisms of dry and wet deposition. Time-dependent wind and turbulence fields are generated with a prognostic mesoscale numerical model and are used to advect and disperse individually released particles that are each assigned a mass. These particles are subjected to mass reduction in two ways depending on their physical location. Particles near the surface experience a decrease in mass using the concept of a dry deposition velocity, while the mass of particles located within areas of precipitation are depleted using a scavenging coefficient. Two levels of complexity are incorporated into the particle model. The simple case assumes constant values of dry deposition velocity and scavenging coefficient, while the more complex case varies the values according to meteorology, surface conditions, release material, and precipitation intensity. Instantaneous and cumulative dry and wet deposition are determined from the mass loss due to these physical mechanisms. A useful means of validating the model results is with data available from a recent accidental release of Cesium-137 from a steel-processing furnace in Algeciras, Spain in May, 1998. This paper describes the deposition modeling technique, as well as a comparison of simulated concentration and deposition with measurements taken for the Algeciras release.

  12. Indeterministic Temporal Logic

    Directory of Open Access Journals (Sweden)

    Trzęsicki Kazimierz

    2015-09-01

    Full Text Available The questions od determinism, causality, and freedom have been the main philosophical problems debated since the beginning of temporal logic. The issue of the logical value of sentences about the future was stated by Aristotle in the famous tomorrow sea-battle passage. The question has inspired Łukasiewicz’s idea of many-valued logics and was a motive of A. N. Prior’s considerations about the logic of tenses. In the scheme of temporal logic there are different solutions to the problem. In the paper we consider indeterministic temporal logic based on the idea of temporal worlds and the relation of accessibility between them.

  13. Spatial and temporal variability of suspended-sediment concentrations in a shallow estuarine environment

    Directory of Open Access Journals (Sweden)

    Catherine A. Ruhl

    2004-05-01

    Full Text Available Shallow subembayments respond differently than deep channels to physical forces acting in estuaries. The U.S. Geological Survey measured suspended-sediment concentrations at five locations in Honker Bay, a shallow subembayment of San Francisco Bay, and the adjacent channel to investigate the spatial and temporal differences between deep and shallow estuarine environments. During the first freshwater pulse of the wet season, the channel tended to transport suspended sediments through the system, whereas the shallow area acted as off-channel storage where deposition would likely occur. Following the freshwater pulse, suspended-sediment concentrations were greater in Honker Bay than in the adjacent deep channel, due to the larger supply of erodible sediment on the bed. However, the tidal variability of suspended-sediment concentrations in both Honker Bay and in the adjacent channel was greater after the freshwater pulse than before. During wind events, suspended-sediment concentrations in the channel were not affected; however, wind played a crucial role in the resuspension of sediments in the shallows. Despite wind-wave sediment resuspension in Honker Bay, tidally averaged suspended-sediment flux was controlled by the flood-dominated currents.

  14. Sequence stratigraphy on an early wet Mars

    Science.gov (United States)

    Barker, Donald C.; Bhattacharya, Janok P.

    2018-02-01

    The evolution of Mars as a water-bearing body is of considerable interest for the understanding of its early history and evolution. The principles of terrestrial sequence stratigraphy provide a useful conceptual framework to hypothesize about the stratigraphic history of the planets northern plains. We present a model based on the hypothesized presence of an early ocean and the accumulation of lowland sediments eroded from highland terrain during the time of the valley networks and later outflow channels. Ancient, global environmental changes, induced by a progressively cooling climate would have led to a protracted loss of surface and near surface water from low-latitudes and eventual cold-trapping at higher latitudes - resulting in a unique and prolonged, perpetual forced regression within basins and lowland depositional environments. The Messinian Salinity Crisis (MSC) serves as a potential terrestrial analogue of the depositional and environmental consequences relating to the progressive removal of large standing bodies of water. We suggest that the evolution of similar conditions on Mars would have led to the emplacement of diagnostic sequences of deposits and regional scale unconformities, consistent with intermittent resurfacing of the northern plains and the progressive loss of an early ocean by the end of the Hesperian era.

  15. Modeling of the transport and deposition of polydispersed particles: Effects of hydrodynamics and spatiotemporal evolution of the deposition rate.

    Science.gov (United States)

    Ma, Enze; Ouahbi, Tariq; Wang, Huaqing; Ahfir, Nasre-Dine; Alem, Abdellah; Hammadi, Ahmed

    2017-11-11

    A time-distance-dependent deposition model is built to investigate the effects of hydrodynamic forces on the transport and deposition of polydispersed particles and the evolution of deposition rates with time and distance. Straining and the heterogeneity of the particle population are considered to play important roles in the decreasing distribution of deposition rates. Numerical simulations were applied in a series of sand column experiments at different fluid velocities for three different porous media. The effects of hydrodynamics forces are elaborated with the systematic variations of deposition dynamic parameters of the proposed model. With retention distributions with particle size as well as temporal and spatial evolutions of deposition rates, the transport and deposition mechanisms of polydispersed particles will be elucidated through the interplay of the variation of the particle size distribution of mobile particle populations and the geometrical change of the porous medium due to retention (straining and blocking). Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Biodiesel production from wet microalgae feedstock using sequential wet extraction/transesterification and direct transesterification processes.

    Science.gov (United States)

    Chen, Ching-Lung; Huang, Chien-Chang; Ho, Kao-Chia; Hsiao, Ping-Xuan; Wu, Meng-Shan; Chang, Jo-Shu

    2015-10-01

    Although producing biodiesel from microalgae seems promising, there is still a lack of technology for the quick and cost-effective conversion of biodiesel from wet microalgae. This study was aimed to develop a novel microalgal biodiesel producing method, consisting of an open system of microwave disruption, partial dewatering (via combination of methanol treatment and low-speed centrifugation), oil extraction, and transesterification without the pre-removal of the co-solvent, using Chlamydomonas sp. JSC4 with 68.7 wt% water content as the feedstock. Direct transesterification with the disrupted wet microalgae was also conducted. The biomass content of the wet microalgae increased to 56.6 and 60.5 wt%, respectively, after microwave disruption and partial dewatering. About 96.2% oil recovery was achieved under the conditions of: extraction temperature, 45°C; hexane/methanol ratio, 3:1; extraction time, 80 min. Transesterification of the extracted oil reached 97.2% conversion within 15 min at 45°C and 6:1 solvent/methanol ratio with simultaneous Chlorophyll removal during the process. Nearly 100% biodiesel conversion was also obtained while conducting direct transesterification of the disrupted oil-bearing microalgal biomass. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Detailed source term estimation of the atmospheric release for the Fukushima Daiichi Nuclear Power Station accident by coupling simulations of an atmospheric dispersion model with an improved deposition scheme and oceanic dispersion model

    Energy Technology Data Exchange (ETDEWEB)

    Katata, G.; Chino, M.; Kobayashi, T. [Japan Atomic Energy Agency (JAEA), Ibaraki (Japan); and others

    2015-07-01

    Temporal variations in the amount of radionuclides released into the atmosphere during the Fukushima Daiichi Nuclear Power Station (FNPS1) accident and their atmospheric and marine dispersion are essential to evaluate the environmental impacts and resultant radiological doses to the public. In this paper, we estimate the detailed atmospheric releases during the accident using a reverse estimation method which calculates the release rates of radionuclides by comparing measurements of air concentration of a radionuclide or its dose rate in the environment with the ones calculated by atmospheric and oceanic transport, dispersion and deposition models. The atmospheric and oceanic models used are WSPEEDI-II (Worldwide version of System for Prediction of Environmental Emergency Dose Information) and SEA-GEARN-FDM (Finite difference oceanic dispersion model), both developed by the authors. A sophisticated deposition scheme, which deals with dry and fog-water depositions, cloud condensation nuclei (CCN) activation, and subsequent wet scavenging due to mixed-phase cloud microphysics (in-cloud scavenging) for radioactive iodine gas (I{sub 2} and CH{sub 3}I) and other particles (CsI, Cs, and Te), was incorporated into WSPEEDI-II to improve the surface deposition calculations. The results revealed that the major releases of radionuclides due to the FNPS1 accident occurred in the following periods during March 2011: the afternoon of 12 March due to the wet venting and hydrogen explosion at Unit 1, midnight of 14 March when the SRV (safety relief valve) was opened three times at Unit 2, the morning and night of 15 March, and the morning of 16 March. According to the simulation results, the highest radioactive contamination areas around FNPS1 were created from 15 to 16 March by complicated interactions among rainfall, plume movements, and the temporal variation of release rates. The simulation by WSPEEDI-II using the new source term reproduced the local and regional patterns of

  18. Atmospheric deposition of polycyclic aromatic hydrocarbons near New England coastal waters

    Science.gov (United States)

    Golomb, D.; Barry, E.; Fisher, G.; Varanusupakul, P.; Koleda, M.; Rooney, T.

    Wet and dry deposition of polycyclic aromatic hydrocarbons (PAHs) was measured at Nahant, Massachusetts, a peninsula jutting into Massachusetts Bay and Wolf Neck, a peninsula jutting into Casco Bay, Maine. Wet deposition (rain and snow) was collected in a funnel which drains into a shielded, temperature controlled receiving bottle. Dry deposition of gaseous and particulate PAHs was collected onto an exposed water surface. PAHs were analyzed by solid phase extraction and gas chromatography-mass spectrometry. Sixteen PAH species were analyzed, ranging from acenaphthylene to coronene. The mean wet deposition rate of the sum of the 16 species is 720 ng m -2 cm -1 precipitation at Nahant, and 831 ng m -2 cm -1 precipitation at Wolf Neck. Wet deposition is attributed to regional PAH emitting sources. Storm patterns appear to bring somewhat higher wet deposition of PAHs to Wolf Neck than to Nahant. The mean dry deposition rate is 95 ng m -2 h -1 at Nahant and 9.3 ng m -2 h -1 at Wolf Neck. The large difference is attributed to the fact that Nahant is close to the urban-industrial metropolitan Boston area and Logan International Airport, whereas Wolf Neck has no major PAH-emitting sources nearby. Individual measurements have an error bracket of ±30%. The Chemical Mass Balance model was used to apportion the dry deposition to source categories. At Nahant, nine samples gave valid statistical attributes with a mean apportionment: jet exhaust 35%, gasoline fueled vehicles 32%, diesel fueled vehicles 17%, wood combustion 13%, others 3%. At Wolf Neck, six samples yielded a mean apportionment: jet exhaust 30%, gasoline vehicles 28%, diesel vehicles 18%, wood combustion 16%, others 8%. There is a considerable variation between the samples. The apportionment is greatly dependent on the quality and selection of the model inputs, i.e. source signatures, which for PAHs are questionable.

  19. Biotic and abiotic controls on diurnal fluctuations in labile soil phosphorus of a wet tropical forest.

    Science.gov (United States)

    Vandecar, Karen L; Lawrence, Deborah; Wood, Tana; Oberbauer, Steven F; Das, Rishiraj; Tully, Katherine; Schwendenmann, Luitgard

    2009-09-01

    The productivity of many tropical wet forests is generally limited by bioavailable phosphorus (P). Microbial activity is a key regulator of P availability in that it determines both the supply of P through organic matter decomposition and the depletion of bioavailable P through microbial uptake. Both microbial uptake and mineralization occur rapidly, and their net effect on P availability varies with soil moisture, temperature, and soil organic matter quantity and quality. Exploring the mechanisms driving P availability at fine temporal scales can provide insight into the coupling of carbon, water, and nutrient cycles, and ultimately, the response of tropical forests to climate change. Despite the recognized importance of P cycling to the dynamics of wet tropical forests and their potential sensitivity to short-term fluctuations in bioavailable P, the diurnal pattern of P remains poorly understood. This study quantifies diurnal fluctuations in labile soil P and evaluates the importance of biotic and abiotic factors in driving these patterns. To this end, measurements of labile P were made every other hour in a Costa Rican wet tropical forest oxisol. Spatial and temporal variation in Bray-extractable P were investigated in relation to ecosystem carbon flux, soil CO2 efflux, soil moisture, soil temperature, solar radiation, and sap-flow velocity. Spatially averaged bi-hourly (every two hours) labile P ranged from 0.88 to 2.48 microg/g across days. The amplitude in labile P throughout the day was 0.61-0.82 microg/g (41-54% of mean P concentrations) and was characterized by a bimodal pattern with a decrease at midday. Labile P increased with soil CO2 efflux and soil temperature and declined with increasing sap flow and solar radiation. Together, soil CO2 efflux, soil temperature, and sap flow explained 86% of variation in labile P.

  20. Elemental mercury removal using a wet scrubber.

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, E.; Livengood, C. D.; Martin, K.; Mendelsohn, M. H.; Zhou, C. Q.

    1999-05-19

    Mercury (Hg) is a toxic metal that is emitted into the environment by both natural and human activities. Acute and chronic exposure to mercury and methyl mercury in humans results in central nervous system damage, kidney damage, and even death. Although some Hg emission sources have been regulated, coal-fired utilities have not been. In anticipation of federal regulations on mercury emissions from coal-fired power plants, Argonne National Laboratory (ANL) has designed a flue gas simulation system to study the removal of elemental mercury. The simulated flue gas enters the system and combines with the inlet mercury vapor (from a calibrated permeation tube), carried by nitrogen gas. This combined gas continues past the flow meter and the pressure gage to the reactor inlet. Inside the reactor chamber, the flue gas is sprayed with NOXSORB{reg_sign}, a chloric acid solution, which reacts with elemental mercury. The amount of reaction (oxidation) of elemental mercury is important since mercury in an oxidized form is highly soluble, In this form, the Hg can be picked up downstream by a wet scrubber from fossil-fuel burning utilities. Experiments on mercury removal from flue gases have been conducted at ANL, with the participation of a senior design team from Purdue University Calumet. Temperature variations ranging from room temperature to 350 F have been studied. Other parameters, such as the concentration of NOXSORB{reg_sign}, were also tested. Furthermore, pump speed and sprayer droplet sizes of the NOXSORB{reg_sign} solution were studied. A literature survey on the current and proposed mercury control legislation, along with the existing control technologies, has been performed as part of the senior design project. With guidance from ANL, an understanding of the simulation system has been developed. This information has been used to determine the mass transfer. Another literature survey was performed on the reaction kinetics of mercury. The information obtained was

  1. Temporal properties of stereopsis

    NARCIS (Netherlands)

    Gheorghiu, E.

    2005-01-01

    The goal of the research presented in this thesis was to investigate temporal properties of disparity processing and depth perception in human subjects, in response to dynamic stimuli. The results presented in various chapters, reporting findings about different temporal aspects of disparity

  2. Temporal Linear System Structure

    NARCIS (Netherlands)

    Willigenburg, van L.G.; Koning, de W.L.

    2008-01-01

    Piecewise constant rank systems and the differential Kalman decomposition are introduced in this note. Together these enable the detection of temporal uncontrollability/unreconstructability of linear continuous-time systems. These temporal properties are not detected by any of the four conventional

  3. Atmospheric Deposition Modeling Results

    Data.gov (United States)

    U.S. Environmental Protection Agency — This asset provides data on model results for dry and total deposition of sulfur, nitrogen and base cation species. Components include deposition velocities, dry...

  4. Electro-Deposition Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The electro-deposition laboratory can electro-deposit various coatings onto small test samples and bench level prototypes. This facility provides the foundation for...

  5. Calcium Pyrophosphate Deposition (CPPD)

    Science.gov (United States)

    ... Patient / Caregiver Diseases & Conditions Calcium Pyrophosphate Deposition (CPPD) Calcium Pyrophosphate Deposition (CPPD) Fast Facts The risk of ... young people, too. Proper diagnosis depends on detecting calcium pyrophosphate crystals in the fluid of an affected ...

  6. Attributes for NHDPlus Catchments (Version 1.1) for the Conterminous United States: Normalized Atmospheric Deposition for 2002, Total Inorganic Nitrogen

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the average normalized atmospheric (wet) deposition, in kilograms, of Total Inorganic Nitrogen for the year 2002 compiled for every...

  7. Attributes for NHDPlus Catchments (Version 1.1) for the Conterminous United States: Normalized Atmospheric Deposition for 2002, Ammonium (NH4)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the average normalized atmospheric (wet) deposition, in kilograms, of Ammonium (NH4) for the year 2002 compiled for every catchment of...

  8. Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: Normalized Atmospheric Deposition for 2002, Nitrate (NO3)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This tabular data set represents the average normalized (wet) deposition, in kilograms per square kilometer multiplied by 100, of Nitrate (NO3) for the year 2002...

  9. Temporal Photon Differentials

    DEFF Research Database (Denmark)

    Schjøth, Lars; Frisvad, Jeppe Revall; Erleben, Kenny

    2010-01-01

    , constituting a temporal smoothing of rapidly changing illumination. In global illumination temporal smoothing can be achieved with distribution ray tracing (Cook et al., 1984). Unfortunately, this, and resembling methods, requires a high temporal resolution as samples has to be drawn from in-between frames. We...... present a novel method which is able to produce high quality temporal smoothing for indirect illumination without using in-between frames. Our method is based on ray differentials (Igehy, 1999) as it has been extended in (Sporring et al., 2009). Light rays are traced as bundles creating footprints, which......The finite frame rate also used in computer animated films is cause of adverse temporal aliasing effects. Most noticeable of these is a stroboscopic effect that is seen as intermittent movement of fast moving illumination. This effect can be mitigated using non-zero shutter times, effectively...

  10. Method for wetting a boron alloy to graphite

    Science.gov (United States)

    Storms, E.K.

    1987-08-21

    A method is provided for wetting a graphite substrate and spreading a a boron alloy over the substrate. The wetted substrate may be in the form of a needle for an effective ion emission source. The method may also be used to wet a graphite substrate for subsequent joining with another graphite substrate or other metal, or to form a protective coating over a graphite substrate. A noneutectic alloy of boron is formed with a metal selected from the group consisting of nickel (Ni), palladium (Pd), and platinum (Pt) with excess boron, i.e., and atomic percentage of boron effective to precipitate boron at a wetting temperature of less than the liquid-phase boundary temperature of the alloy. The alloy is applied to the substrate and the graphite substrate is then heated to the wetting temperature and maintained at the wetting temperature for a time effective for the alloy to wet and spread over the substrate. The excess boron is evenly dispersed in the alloy and is readily available to promote the wetting and spreading action of the alloy. 1 fig.

  11. Hydrodynamics of a Multistage Wet Scrubber Incineration Conditions

    Science.gov (United States)

    Said, M. M.; Manyele, S. V.; Raphael, M. L.

    2012-01-01

    The objective of the study was to determine the hydrodynamics of the two stage counter-current cascade wet scrubbers used during incineration of medical waste. The dependence of the hydrodynamics on two main variables was studied: Inlet air flow rate and inlet liquid flow rate. This study introduces a new wet scrubber operating features, which are…

  12. The Influence of Wetting Rate and Electrolyte Concentration on the ...

    African Journals Online (AJOL)

    Substantial macroscopic swelling of rapidly wetted soil was attributed to air compressed into the largest available voids. Consequent soil matrix failure resulted in macroscopic swelling and increased sorption of water. Hydraulic conductivity appeared to be a non-linear function of wetting rate over the range w = 0-30 mm ...

  13. Phase change materials and the perception of wetness

    NARCIS (Netherlands)

    Bergmann Tiest, W.M.; Kosters, N.D.; Kappers, A.M.L.; Daanen, H.A.M.

    2012-01-01

    Phase change materials (PCMs) are increasingly incorporated in textiles in order to serve as a thermal buffer when humans change from a hot to a cold environment and the reverse. Due to the absence of wetness sensors in the skin, cooling of the skin may be perceived as a sensation of wetness instead

  14. Phase Change Materials and the perception of wetness.

    NARCIS (Netherlands)

    Bergmann Tiest, W.M.; Kappers, A.M.L.; Daanen, H.A.M.

    2012-01-01

    Phase change materials (PCMs) are increasingly incorporated in textiles in order to serve as a thermal buffer when humans change from a hot to a cold environment and the reverse. Due to the absence of wetness sensors in the skin, cooling of the skin may be perceived as a sensation of wetness instead

  15. Evaluation of wetting ability of five new saliva substitutes on ...

    African Journals Online (AJOL)

    Introduction: The aim of this study was to evaluate & compare the wetting ability of five saliva substitutes & distilled water on heat-polymerized acrylic resin. Contact angle of the saliva substitute on denture base can be taken as an indicator of wettability. Good wetting of heat-polymerized acrylic resin is critical for optimum ...

  16. Comparative Batch and Column Evaluation of Thermal and Wet ...

    African Journals Online (AJOL)

    ABSTRACT: The efficiency of regenerated spent commercial activated carbon for synthetic dye removal was studied using thermal and wet ... Keywords: Activated Carbon, Methyl Red, Chromatography Capacity, Wet and Thermal Regeneration. INTRODUCTION ... processes in wastewater treatment. A number of techniques ...

  17. Southern African Regional Science Initiative (SAFARI 2000): wet season campaigns

    CSIR Research Space (South Africa)

    Otter, LB

    2002-03-01

    Full Text Available The Southern African Regional Science Initiative (SAFARI 2000) involved two wet season and one dry season field campaigns. This paper reports on the wet season campaigns. The first was conducted at five sites along the Kalahari Transect in Zambia...

  18. Effect of Hydrochloric Acid, Mechanical Scarification, Wet Heat ...

    African Journals Online (AJOL)

    Michael Horsfall

    HCL), Wet heat. ABSTRACT; The effect of different ... treatments observed showed 100% for wet heat, 90% for scarification (sand paper) and 70% for HCL of 50% ... the principle constant being a dry season of 5-7 month/year. It may grow in ...

  19. Fluorinated Silsesquioxanes: Structure, Solubility, and Wetting (Briefing charts)

    Science.gov (United States)

    2015-08-01

    Charts 3. DATES COVERED (From - To) July 2015-July 2015 4. TITLE AND SUBTITLE FLUORINATED SILSESQUIOXANES: STRUCTURE, SOLUBILITY , AND WETTING...FLUORINATED SILSESQUIOXANES: STRUCTURE, SOLUBILITY , AND WETTING Joseph Mabry, Andrew Guenthner, Scott Iacono, Raymond Campos, Sean Ramirez, Brian Moore...Crystalline solids • Soluble in fluorinated solvents 5DISTRIBUTION A. Approved for public release; distribution unlimited. • Spin-cast surface of FD

  20. Tactile cues significantly modulate the perception of sweat-induced skin wetness independently of the level of physical skin wetness.

    Science.gov (United States)

    Filingeri, Davide; Fournet, Damien; Hodder, Simon; Havenith, George

    2015-06-01

    Humans sense the wetness of a wet surface through the somatosensory integration of thermal and tactile inputs generated by the interaction between skin and moisture. However, little is known on how wetness is sensed when moisture is produced via sweating. We tested the hypothesis that, in the absence of skin cooling, intermittent tactile cues, as coded by low-threshold skin mechanoreceptors, modulate the perception of sweat-induced skin wetness, independently of the level of physical wetness. Ten males (22 yr old) performed an incremental exercise protocol during two trials designed to induce the same physical skin wetness but to induce lower (TIGHT-FIT) and higher (LOOSE-FIT) wetness perception. In the TIGHT-FIT, a tight-fitting clothing ensemble limited intermittent skin-sweat-clothing tactile interactions. In the LOOSE-FIT, a loose-fitting ensemble allowed free skin-sweat-clothing interactions. Heart rate, core and skin temperature, galvanic skin conductance (GSC), and physical (w(body)) and perceived skin wetness were recorded. Exercise-induced sweat production and physical wetness increased significantly [GSC: 3.1 μS, SD 0.3 to 18.8 μS, SD 1.3, P FIT and LOOSE-FIT (P > 0.05). However, the limited intermittent tactile inputs generated by the TIGHT-FIT ensemble reduced significantly whole-body and regional wetness perception (P < 0.01). This reduction was more pronounced when between 40 and 80% of the body was covered in sweat. We conclude that the central integration of intermittent mechanical interactions between skin, sweat, and clothing, as coded by low-threshold skin mechanoreceptors, significantly contributes to the ability to sense sweat-induced skin wetness. Copyright © 2015 the American Physiological Society.

  1. Reversible wetting of titanium dioxide films

    Science.gov (United States)

    Toh, A. G. G.; Nolan, M. G.; Cai, R.; Butler, D. L.

    2007-12-01

    Titanium dioxide (TiO II) films were rendered hydrophilic through ultraviolet (UV) light irradiation (254nm) and returned to their previous hydrophobic condition when exposed to a sealed pressurized nitrogen atmosphere. UV light irradiation on TiO II films resulted in super-hydrophilic surfaces with water contact angles of 40°. The switching of TiO II surface wettability could be repeated on the same surface with little hysteresis in water contact angle values. The mechanism behind the hydrophilic and hydrophobic reversal in TiO II surfaces is proposed to be due to UV light mediated photocatalysis and physio- adsorption of N II molecules respectively. The non-intrusive control of TiO II surface wettability could be an attractive alternative to other wettability-based microfluidic valving strategies like electrowetting and photochromic wetting variation. The above results are discussed in terms of the potential use of the films in wettability based valving and repeated wettability patterning of TiO II surfaces for open and sealed microfluidic systems.

  2. Wet process technology in the semiconductor manufacturing process. 1. Physics and chemistry of wet cleaning process; Handotai process ni okeru wet process. Wet senjo no butsuri kagaku

    Energy Technology Data Exchange (ETDEWEB)

    Ryuta, J. [Mitsubishi Materials Corp., Tokyo (Japan)

    1995-03-05

    The wet cleaning consists of a cleaning process in chemicals and a rinse process using ultra-pure water. Among a series of cleaning process, this paper focuses on the SC1 (standard cleaning 1) process using NH4OH, H2O2, and H2O. During the SC1 process, two reactions progress simultaneously, i.e., natural oxidation and etching reactions on the wafer surface. As a consequence of measurement of the oxide film thickness, it was found that the reaction rate during the initial oxidation is extremely high. As a result of measurement of the etching rate, it was also found that the etching reaction is affected by the oxidation reaction. It is illustrated that pits, which are caused by defects in the crystal, are formed during the repeated SC1 process. It is also illustrated that the adsorption and desorption of Fe occur simultaneously on the wafer surface during the SC1 process. It was found that a clean wafer surface can be obtained by removing the particles and metal impurities in the cleaning liquid. 10 refs., 12 figs., 1 tab.

  3. Photochemical organonitrate formation in wet aerosols

    Directory of Open Access Journals (Sweden)

    Y. B. Lim

    2016-10-01

    Full Text Available Water is the most abundant component of atmospheric fine aerosol. However, despite rapid progress, multiphase chemistry involving wet aerosols is still poorly understood. In this work, we report results from smog chamber photooxidation of glyoxal- and OH-containing ammonium sulfate or sulfuric acid particles in the presence of NOx and O3 at high and low relative humidity. Particles were analyzed using ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS. During the 3 h irradiation, OH oxidation products of glyoxal that are also produced in dilute aqueous solutions (e.g., oxalic acids and tartaric acids were formed in both ammonium sulfate (AS aerosols and sulfuric acid (SA aerosols. However, the major products were organonitrogens (CHNO, organosulfates (CHOS, and organonitrogen sulfates (CHNOS. These were also the dominant products formed in the dark chamber, indicating non-radical formation. In the humid chamber (> 70 % relative humidity, RH, two main products for both AS and SA aerosols were organonitrates, which appeared at m ∕ z− 147 and 226. They were formed in the aqueous phase via non-radical reactions of glyoxal and nitric acid, and their formation was enhanced by photochemistry because of the photochemical formation of nitric acid via reactions of peroxy radicals, NOx and OH during the irradiation.

  4. Cardiovascular magnetic resonance in wet beriberi

    Directory of Open Access Journals (Sweden)

    Giri Shivraman

    2011-08-01

    Full Text Available Abstract The clinical presentation of beriberi can be quite varied. In the extreme form, profound cardiovascular involvement leads to circulatory collapse and death. This case report is of a 72 year-old male who was admitted to the Neurology inpatient ward with progressive bilateral lower extremity weakness and parasthesia. He subsequently developed pulmonary edema and high output cardiac failure requiring intubation and blood pressure support. With the constellation of peripheral neuropathy, encephalopathy, ophthalmoplegia, unexplained heart failure, and lactic acidosis, thiamine deficiency was suspected. He was empirically initiated on thiamine replacement therapy and his thiamine level pre-therapy was found to be 23 nmol/L (Normal: 80-150 nmol/L, consistent with the diagnosis of beriberi. Cardiovascular magnetic resonance (CMR showed severe left ventricular systolic dysfunction, markedly increased myocardial T2, and minimal late gadolinium enhancement (LGE. After 5 days of daily 100 mg IV thiamine and supportive care, the hypotension resolved and the patient was extubated and was released from the hospital 3 weeks later. Our case shows via CMR profound myocardial edema associated with wet beriberi.

  5. Metal--nanotube interactions -- wetting properties

    Science.gov (United States)

    Zhu, Ruzeng; Cui, Shuwen

    2011-03-01

    The wetting properties of metal nanoparticles in large-diameter single Carbon nanotubes (LDSWNT) is studied by considering the size effect on surface tension of the metal cluster. For the case of macro-nonwetting, we get finite critical atom number N such that the metal cluster with any atom number smaller than it has contact angle π , and so it shrinks into a ball. For an experiential formula of the surface tension of cluster expressed by the number of atoms, we determine the parameters in it for Pd and Pt respectively by density functional theory (DFT). Taking a graphene sheet as a representative of LDSWNT and using the known data of the surface tensions of solid and liquid, we obtain solid-liquid interface tension through Berthelot rule. Based on these results, we obtain N=5 for Pd and N=6 for Pt. For cluster containing 13 Pd atoms and that containing 13 Pt atoms, we use the above mentioned experiential formula to obtain their contact angles in LDSWNT consistent with those shown by the pictures given by DFT (A Maiti and A Ricca, Chem Phys Letters 395 (2004) 7--11), and thus the validity of our method is proved. Project supported by the National Natural Science Foundation of China (Grant No.11072242).

  6. Deposit Games with Reinvestment

    NARCIS (Netherlands)

    van Gulick, G.; Borm, P.E.M.; De Waegenaere, A.M.B.; Hendrickx, R.L.P.

    2007-01-01

    In a deposit game coalitions are formed by players combining their capital. The proceeds of their investments then have to be divided among those players. The current model extends earlier work on capital deposits by allowing reinvestment of returns. Two specific subclasses of deposit games are

  7. Wetting of silicone oil onto a cell-seeded substrate

    Science.gov (United States)

    Lu, Yongjie; Chan, Yau Kei; Chao, Youchuang; Shum, Ho Cheung

    2017-11-01

    Wetting behavior of solid substrates in three-phase systems containing two immiscible liquids are widely studied. There exist many three-phase systems in biological environments, such as droplet-based microfluidics or tamponade of silicone oil for eye surgery. However, few studies focus on wetting behavior of biological surfaces with cells. Here we investigate wetting of silicone oil onto cell-seeded PMMA sheet immersed in water. Using a simple parallel-plate cell, we show the effect of cell density, viscosity of silicone oil, morphology of silicone oil drops and interfacial tension on the wetting phenomenon. The dynamics of wetting is also observed by squeezing silicone oil drop using two parallel plates. Experimental results are explained based on disjoining pressure which is dependent on the interaction of biological surfaces and liquid used. These findings are useful for explaining emulsification of silicone oil in ophthalmological applications.

  8. Using wet microalgae for direct biodiesel production via microwave irradiation.

    Science.gov (United States)

    Cheng, Jun; Yu, Tao; Li, Tao; Zhou, Junhu; Cen, Kefa

    2013-03-01

    To address the large energy consumption of microalgae dewatering and to simplify the conventional two-step method (cellular lipid extraction and lipid transesterification) for biodiesel production, a novel process for the direct conversion of wet microalgae biomass into biodiesel by microwave irradiation is proposed. The influences of conventional thermal heating and microwave irradiation on biodiesel production from wet microalgae biomass were investigated. The effects of using the one-step (simultaneous lipid extraction and transesterification) and two-step methods were also studied. Approximately 77.5% of the wet microalgal cell walls were disrupted under microwave irradiation. The biodiesel production rate and yield from wet microalgae biomass obtained through the one-step process using microwave irradiation were 6-fold and 1.3-fold higher than those from wet microalgae obtained through the two-step process using conventional heating. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Experimental and Theoretical Investigations of Wet Flue Gas Desulphurisation

    DEFF Research Database (Denmark)

    Kiil, Søren

    This thesis describes experimental and theoretical investigations of wet flue gas desulphurisa-tion (FGD). A review of the current knowledge of the various rate determining steps in wet FGD plants is presented. The experimental work covers laboratory studies as well as pilot- and full-scale...... was found to decrease the rate of gas phase mass transport with up to 15 %, though the effect could not be correlated.A detailed model for a wet FGD pilot plant, based on the falling film principle, was devel-oped. All important rate determining steps, absorption of SO2, oxidation of HSO3-, dissolution...... - 333 K, pertinent for full-scale wet FGD packed towers. The possibility of co-firing straw and coal was investigated in a full-scale power plant. No ef-fects on the overall performance of the wet FGD plant were observed, though laboratory ex-periments with fine dust and fly ash from the full-scale...

  10. Temporal properties of stereopsis

    Science.gov (United States)

    Gheorghiu, E.

    2005-03-01

    The goal of the research presented in this thesis was to investigate temporal properties of disparity processing and depth perception in human subjects, in response to dynamic stimuli. The results presented in various chapters, reporting findings about different temporal aspects of disparity processing, are based on psychophysical experiments and computational model analysis. In chapter 1 we investigated which processes of binocular depth perception in dynamic random-dot stereograms (DRS), i.e., tolerance for interocular delays and temporal integration of correlation, are responsible for the temporal flexibility of the stereoscopic system. Our results demonstrate that (i) disparities from simultaneous monocular inputs dominate those from interocular delayed inputs; (ii) stereopsis is limited by temporal properties of monocular luminance mechanisms; (iii) depth perception in DRS results from cross-correlation-like operation on two simultaneous monocular inputs that represent the retinal images after having been subjected to a process of monocular temporal integration of luminance. In chapter 2 we examined what temporal information is exploited by the mechanisms underlying stereoscopic motion in depth. We investigated systematically the influence of temporal frequency on binocular depth perception in temporally correlated and temporally uncorrelated DRS. Our results show that disparity-defined depth is judged differently in temporally correlated and uncorrelated DRS above a temporal frequency of about 3 Hz. The results and simulations indicate that: (i) above about 20 Hz, the complete absence of stereomotion is caused by temporal integration of luminance; (ii) the difference in perceived depth in temporally correlated and temporally uncorrelated DRS for temporal frequencies between 20 and 3 Hz, is caused by temporal integration of disparity. In chapter 3 we investigated temporal properties of stereopsis at different spatial scales in response to sustained and

  11. Chronic nitrogen deposition influences the chemical dynamics ...

    Science.gov (United States)

    Atmospheric nitrogen deposition induces a forest carbon sink across broad parts of the Northern Hemisphere; this carbon sink may partly result from slower litter decomposition. Although microbial responses to experimental nitrogen deposition have been well-studied, evidence linking these microbial responses to changes in the degradation of specific compounds in decaying litter is sparse. We used wet chemistry and Fourier transform infrared spectroscopy (FTIR) methodologies to study the effects of chronic simulated nitrogen deposition on leaf litter and fine root chemistry during a three-year decomposition experiment at four northern hardwood forests in the north-central USA. Leaf litter and fine roots were highly different in initial chemistry such as concentrations of acid-insoluble fraction (AIF, or Klason lignin) and condensed tannins (CTs). These initial differences persisted over the course of decomposition. Results from gravimetrically-defined AIF and lignin/carbohydrate reference IR peak ratios both provide evidence that lignin in fine roots was selectively preserved under simulated nitrogen deposition. Lignin/carbohydrate peak ratios were strongly correlated with AIF, suggesting that AIF is a good predictor of lignin. Because AIF is abundant in fine roots, slower AIF degradation was the major driver of the slower fine root decomposition under nitrogen enrichment, explaining 73.9 % of the additional root mass retention. Nitrogen enrichment also slowed the

  12. Repeated bouncing of drops on wetting and non-wetting surfaces mediated by a persisting thin air film

    NARCIS (Netherlands)

    de Ruiter, J.; Lagraauw, R.; van den Ende, Henricus T.M.; Mugele, Friedrich Gunther

    2014-01-01

    Abstract Submitted for the DFD14 Meeting of The American Physical Society Repeated bouncing of drops on wetting and non-wetting sur- faces mediated by a persisting thin air lm JOLET DE RUITER, RUDY LAGRAAUW, DIRK VAN DEN ENDE, FRIEDER MUGELE, MESA+ Institute for Nanotechnology, University of Twente

  13. Quantification of wet-work exposure in nurses using a newly developed wet-work exposure monitor

    NARCIS (Netherlands)

    Visser, Maaike J.; Behroozy, Ali; Verberk, Maarten M.; Semple, Sean; Kezic, Sanja

    2011-01-01

    Occupational contact dermatitis (OCD) is an important work-related disease. A major cause of OCD is 'wet work': frequent contact of the skin with water, soap, detergents, or occlusive gloves. The German guidance TRGS 401 recommends that the duration of wet work (including use of occlusive gloves)

  14. Imaging of oil layers, curvature and contact angle in a mixed‐wet and a water‐wet carbonate rock

    National Research Council Canada - National Science Library

    Singh, Kamaljit; Bijeljic, Branko; Blunt, Martin J

    2016-01-01

    ...‐wet), whereas the untreated rock (without doped oil) was weakly water‐wet (θ=47 ± 9°). Using X‐ray micro‐tomography, we show that the brine displaces oil in larger pores during brine injection in the mixed...

  15. The fate of SOC during the processes of water erosion and subsequent deposition: a field study.

    Science.gov (United States)

    van Hemelryck, H.; Govers, G.; van Oost, K.; Merckx, R.

    2009-04-01

    Globally soils are the largest terrestrial pool of carbon (C). A relatively small increase or decrease in soil carbon content due to changes in land use or management practices could therefore result in a significant net exchange of C between the soil C reservoir and the atmosphere. As such, the geomorphic processes of water and tillage erosion have been identified to significantly impact on this large pool of soil organic carbon (SOC). Soil erosion, transport and deposition not only result in redistribution of sediments and associated carbon within a landscape, but also affect the exchange of C between the pedosphere and the atmosphere. The direction and magnitude of an erosion-induced change in the global C balance is however a topic of much debate as opposing processes interact: i) At eroding sites a net uptake of C could be the result of reduced respiration rates and continued inputs of newly produced carbon. ii) Colluvial deposition of eroded sediment and SOC leads to the burial of the original topsoil and this may constrain the decomposition of its containing SOC. iii) Eroded sediment could be transported to distal depositional environments or fluvial systems where it will either be conserved or become rapidly mineralized. iv) Increased emission of CO2 due to erosion may result from the disruptive energy of erosive forces causing the breakdown of aggregates and exposing previously protected SOC to microbial decomposition. The above-mentioned processes show a large spatial and temporal variability and assessing their impact requires an integrated modeling approach. However uncertainties about the basic processes that accompany SOC displacement are still large. This study focuses on one of these large information gaps: the fate of eroded and subsequently deposited SOC. A preceding experimental study (Van Hemelryck et al., 2008) was used to identify controlling factors (erosional intensity, changes in soil structure,…). However this experimental research

  16. Towards Temporal Graph Databases

    OpenAIRE

    Campos, Alexander; Mozzino, Jorge; Vaisman, Alejandro

    2016-01-01

    In spite of the extensive literature on graph databases (GDBs), temporal GDBs have not received too much attention so far. Temporal GBDs can capture, for example, the evolution of social networks across time, a relevant topic in data analysis nowadays. In this paper we propose a data model and query language (denoted TEG-QL) for temporal GDBs, based on the notion of attribute graphs. This allows a straightforward translation to Neo4J, a well-known GBD. We present extensive examples of the use...

  17. Wet melting along the Tonga Volcanic Arc

    Science.gov (United States)

    Cooper, L. B.; Plank, T.; Arculus, R. J.; Hauri, E. H.; Hall, P.

    2010-12-01

    Melting in the mantle at convergent margins is driven by water from the subducting slab. Previous work has found a strong role for water-fluxed melting from correlations between the concentration of water in the mantle source, (H2O)o, and the extent of melting beneath backarcs, Fba. Here we explore how wet melting beneath the Lau Backarc Basin relates to that beneath the Tonga Arc, Farc, by providing the first systematic study of water contents in Tonga arc magmas. We have measured volatiles and major and trace elements in melt inclusions, glasses, and whole rocks obtained from recently sampled submarine and subaerial Tonga arc volcanoes. The compositions are varied and range mostly between andesite and basalt/boninite, and least-degassed water contents range from 2 to 5 wt%. We estimate (H2O)o and Farc independently by combining pressure (P) and temperature (T) estimates from an olivine-orthopyroxene-melt thermobarometer with a wet melting productivity model. When P, T, and (H2O)o are known, Farc is uniquely constrained. Results for the volcanoes in the Tonga Arc are bimodal with respect to T: volcanoes located near active backarc spreading centers reflect cooler melting (~1275°C) than those located far from active spreading centers (~1365°C). The cooler primary T’s may result from removal of the heat of fusion during prior melting beneath the Lau backarc, Fba. In the northern portion of the arc, the warmest primary T’s may be due to proximity to the Samoan mantle plume. Farc varies non-systematically along-strike, indicating that Fba is the primary driver of along-arc variability in primary melt compositions. Farc can also be used to calculate the TiO2 concentration of the arc mantle source, (TiO2)o (a proxy for source depletion), which varies monotonically along the Tonga Arc. Arc volcanoes adjacent to the Southern Lau Rifts and Valu Fa Ridge melt mantle with a fertile N-MORB TiO2, while those adjacent to the northern extent of the Eastern Lau Spreading

  18. Flame Stabilization on Microscopic Scale of Wet Biogas with Microflame

    Science.gov (United States)

    Ida, Tamio; Fuchihata, Manabu; Mizuno, Satoru

    Harvesting, transportation, energy conversion and the high-efficient utilization, cascade method and market formation besides become with the indispensable element in order to utilize the biomass resource. There are two type biogases; it is gasified gas from dried biomass by partially combustion and wet biogas from wet biomass by methane fermentation, especially from the livestock excrement resources. This paper discusses an experimental study for flame stabilization on microscopic scale with wet biogas (mainly 0.6CH4+0.4CO2). In this study, the microflame with the wet biogas fuels are formed by the diffusion flame on the coppered straight pipes of inner diameter 0.02mm ˜ 1.5mm. This study is obtained stability mapping on microscopic scale of formed microflame by wet biogas fuels. The flame stability limit conditions on microscopic scale of wet biogas is drawn with blow off and extinction flame double limit lines. It is suggested that minimum mixing spatial scale change by the each mixing ratio of the wet biogas.

  19. Temporal Lobe Seizure

    Science.gov (United States)

    ... pregnancy Temporal lobe seizure Symptoms & causes Diagnosis & treatment Advertisement Mayo Clinic does not endorse companies or products. ... a Job Site Map About This Site Twitter Facebook Google YouTube Pinterest Mayo Clinic is a not- ...

  20. Temporal Lobe Seizure

    Science.gov (United States)

    ... functions, including having odd feelings — such as euphoria, deja vu or fear. During a temporal lobe seizure, you ... include: A sudden sense of unprovoked fear A deja vu experience — a feeling that what's happening has happened ...

  1. Multisensory temporal numerosity judgment

    NARCIS (Netherlands)

    Philippi, T.; Erp, J.B.F. van; Werkhoven, P.J.

    2008-01-01

    In temporal numerosity judgment, observers systematically underestimate the number of pulses. The strongest underestimations occur when stimuli are presented with a short interstimulus interval (ISI) and are stronger for vision than for audition and touch. We investigated if multisensory

  2. Neocortical Temporal Lobe Epilepsy

    Science.gov (United States)

    Bercovici, Eduard; Kumar, Balagobal Santosh; Mirsattari, Seyed M.

    2012-01-01

    Complex partial seizures (CPSs) can present with various semiologies, while mesial temporal lobe epilepsy (mTLE) is a well-recognized cause of CPS, neocortical temporal lobe epilepsy (nTLE) albeit being less common is increasingly recognized as separate disease entity. Differentiating the two remains a challenge for epileptologists as many symptoms overlap due to reciprocal connections between the neocortical and the mesial temporal regions. Various studies have attempted to correctly localize the seizure focus in nTLE as patients with this disorder may benefit from surgery. While earlier work predicted poor outcomes in this population, recent work challenges those ideas yielding good outcomes in part due to better localization using improved anatomical and functional techniques. This paper provides a comprehensive review of the diagnostic workup, particularly the application of recent advances in electroencephalography and functional brain imaging, in neocortical temporal lobe epilepsy. PMID:22953057

  3. Massive temporal lobe cholesteatoma

    National Research Council Canada - National Science Library

    Waidyasekara, Pasan; Dowthwaite, Samuel A; Stephenson, Ellison; Bhuta, Sandeep; McMonagle, Brent

    2015-01-01

    .... There had been no relevant symptoms in the interim until 6 weeks prior to this presentation. Imaging demonstrated a large right temporal lobe mass contiguous with the middle ear and mastoid cavity with features consistent with cholesteatoma...

  4. Massive Temporal Lobe Cholesteatoma

    National Research Council Canada - National Science Library

    Waidyasekara, Pasan; Dowthwaite, Samuel A; Stephenson, Ellison; Bhuta, Sandeep; McMonagle, Brent

    2015-01-01

    .... There had been no relevant symptoms in the interim until 6 weeks prior to this presentation. Imaging demonstrated a large right temporal lobe mass contiguous with the middle ear and mastoid cavity with features consistent with cholesteatoma...

  5. A pilot-scale study of wet torrefaction treatment for upgrading palm oil empty fruit bunches as clean solid fuel

    Science.gov (United States)

    Gusman, M. H.; Sastroredjo, P. N. E.; Prawisudha, P.; Hardianto, T.; Pasek, A. D.

    2017-05-01

    Less utilized empty fruit bunch (EFB) is seldom used as solid biofuel due to its high alkali content that potentially cause ash deposit called slagging and fouling. This phenomenon could harm biomass-fired power plant equipment. Some pre-treatment of EFB is needed to reduce EFB ash deposit potential. The effect of wet torrefaction pre-treatment in laboratory scale was successfully proven in decreasing slagging and fouling potential while increasing EFB calorific value that could fulfill clean solid fuel criteria. This research focuses on wet torrefaction process that conducted on a pilot scale with the capacity of 250 liters. It was found that wet torrefaction process can improve the product’s calorific value up to 9.41% while reduce its ash content down to 1.01% comparing to the raw EFB. The reduction of ash content also leads to the reduction of slagging and fouling tendency that presents in terms of alkali index. Alkali index is a quantitative method that can be calculated after obtaining metal oxides fraction on solid fuel. Metal oxides could be obtained by using energy dispersive x-ray spectroscopy.

  6. Partial wetting gas-liquid segmented flow microreactor.

    Science.gov (United States)

    Kazemi Oskooei, S Ali; Sinton, David

    2010-07-07

    A microfluidic reactor strategy for reducing plug-to-plug transport in gas-liquid segmented flow microfluidic reactors is presented. The segmented flow is generated in a wetting portion of the chip that transitions downstream to a partially wetting reaction channel that serves to disconnect the liquid plugs. The resulting residence time distributions show little dependence on channel length, and over 60% narrowing in residence time distribution as compared to an otherwise similar reactor. This partial wetting strategy mitigates a central limitation (plug-to-plug dispersion) while preserving the many attractive features of gas-liquid segmented flow reactors.

  7. Wet combing for the eradication of head lice.

    Science.gov (United States)

    2013-03-01

    Manual removal (using conditioner and comb or a wet comb) can be used in the treatment of head lice. Head lice infestation (Pediculosis humanus capitis) is a common problem. It is diagnosed by visualising the lice. As half of people infested with head lice will not scratch, all people in contact with a person affected with head lice should be manually checked for infestations. Wet combing is easily and safely performed at home, but persistence is needed. This article describes the process of head lice removal using a wet comb. It has NHMRC Level 2 evidence of efficacy and no serious adverse effects have been reported.

  8. Modelling of wetting tests for a natural pyroclastic soil

    Directory of Open Access Journals (Sweden)

    Moscariello Mariagiovanna

    2016-01-01

    Full Text Available The so-called wetting-induced collapse is one of the most common problems associated with unsaturated soils. This paper applies the Modified Pastor-Zienkiewicz model (MPZ to analyse the wetting behaviour of undisturbed specimens of an unsaturated air-fall volcanic (pyroclastic soil originated from the explosive activity of the Somma-Vesuvius volcano (Southern Italy. Both standard oedometric tests, suction-controlled oedometeric tests and suction-controlled isotropic tests are considered. The results of the constitutive modelling show a satisfactory capability of the MPZ to simulate the variations of soil void ratio upon wetting, with negligible differences among the measured and the computed values.

  9. Atmospheric depositions of persistent pollutants: methodological aspects and values from case studies

    Directory of Open Access Journals (Sweden)

    Gaetano Settimo

    2015-12-01

    Full Text Available Deposition monitoring, already in use by government control organizations of various countries, contributes to an important increase in experimental knowledge on pollutant deposition fluxes, on their environmental fate and on the possible effects on human health. At the European level, the necessity to consider with extreme attention the environmental contamination due to deposition, has brought to adopt a series of legislative measures and recommendations; this has contributed to set up environmental surveillance systems and monitoring campaigns for a series of pollutants which may accumulate in the environment as persistent organic pollutants (POPs and for metals. More recently, with DL.vo 155/2010, the necessity to consider, in the development of monitoring stations, the possibility to detect also data on deposition rates which represent a non-direct exposure of the population through the food chain. For sampling the Decree considers only two types of depositions: for total deposition (bulk and Bergerhoff and wet only deposition.

  10. Wet gas compression. Experimental investigation of the aerodynamics within a centrifugal compressor exposed to wet gas

    Energy Technology Data Exchange (ETDEWEB)

    Gruener, Trond Gammelsaeter

    2012-07-01

    The demand for more efficient oil and gas production requires improved technology to increase production rates and enhance profitable operation. The centrifugal compressor is the key elements in the compression system. Preliminary studies of wet gas compressor concepts have demonstrated the benefits of wet gas boosting. An open-loop test facility was designed for single-stage wet gas compressor testing. Experimental investigators have been performed to reveal the impact of liquid on the aerodynamics of centrifugal compressor. The investigation consisted of two test campaigns with different impeller/diffuser configurations. Atmospheric air and water were used as experimental fluids. The two configurations showed a different pressure ratio characteristics when liquid as present. The results from test campaign A demonstrated a pronounced pressure ratio decrease at high flow and a minor pressure ration increase pressure ratio with reducing gas mass fraction (GMF). The deviation in pressure ratio characteristic for the two test campaigns was attributed to the volute operating characteristic. Both impeller/diffuser configurations demonstrated a reduction in maximum volume flow with decreasing GMF. The impeller pressure ratio was related to the diffuser and/or the volute performance). Air and water are preferable experimental fluids for safety reasons and because a less extensive facility design is required. An evaluation of the air/water tests versus hydrocarbon tests was performed in order to reveal whether the results were representative. Air/water tests at atmospheric conditions reproduced the general performance trend of hydrocarbon wet gas compressor tests with an analogous impeller at high pressures. Aerodynamic instability limits the operating range because of feasible severe damage of the compressor and adverse influence on the performance. It is essential to establish the surge margin at different operating conditions. A delayed instability inception was

  11. Evolution of ore deposits on terrestrial planets

    Science.gov (United States)

    Burns, R. G.

    1991-01-01

    Ore deposits on terrestrial planets materialized after core formation, mantle evolution, crustal development, interactions of surface rocks with the hydrosphere and atmosphere, and, where life exists on a planet, the involvement of biological activity. Core formation removed most of the siderophilic and chalcophilic elements, leaving mantles depleted in many of the strategic and noble metals relative to their chondritic abundances. Basaltic magma derived from partial melting of the mantle transported to the surface several metals contained in immiscible silicate and sulfide melts. Magmatic ore deposits were formed during cooling, fractional crystallization and density stratification from the basaltic melts. Such ore deposits found in earth's Archean rocks were probably generated during early histories of all terrestrial planets and may be the only types of igneous ores on Mars. Where plate tectonic activity was prevalent on a terrestrial planet, temporal evolution of ore deposits took place. Repetitive episodes of subduction modified the chemical compositions of the crust and upper mantles, leading to porphyry copper and molybdenum ores in calc-alkaline igneous rocks and granite-hosted tin and tungsten deposits. Such plate tectonic-induced mineralization in relatively young igneous rocks on earth may also have produced hydrothermal ore deposits on Venus in addition to the massive sulfide and cumulate chromite ores associated with Venusian mafic igneous rock. Sedimentary ore deposits resulting from mechanical and chemical weathering in reducing atmospheres in Archean earth included placer deposits (e.g., uraninite, gold, pyrite ores). Chromite, ilmenite, and other dense unreactive minerals could also be present on channel floors and in valley networks on Mars, while banded iron formations might underlie the Martian northern plains regions. As oxygen evolved in earth's atmosphere, so too did oxide ores. By analogy, gossans above sulfide ores probably occur on Mars

  12. Methane fluxes from a wet puna ecosystem in the Peruvian Andes

    Science.gov (United States)

    Jones, Sam; Diem, Torsten; Priscila Huaraca Quispe, Lidia; Quispe Ccahuana, Adan Julian; Meir, Patrick; Arn Teh, Yit

    2014-05-01

    Discrepancies exist between top-down and bottom-up estimates of the tropical South American atmospheric methane budget. This suggests that current source-sink inventories fail to adequately characterise the landscapes of the region. This may be particularly true of Andean environments where very few field observations have been made. The high tropical Andes, between tree and permanent snow-lines, is home to diverse grass, shrub and giant rosette dominated ecosystems known variously from Venezuela to northern Chile and Argentina as paramo, jalca and puna. In humid regions these are characterised by wet, organic-rich mineral soils, peat-forming wetlands and shallow lakes. Such conditions are likely to promote methane production and potentially represent a regionally significant source to the atmosphere that should be considered. We report on methane fluxes from a bunch-grass dominated puna habitat at 3500 m above sea level in south-eastern Peru. Mean annual temperature and precipitation are 11 °C and 2500 mm, respectively. Temperature is aseasonal but experiences considerable diurnal variations with overnight frosting common-place. In contrast, rainfall is intensely episodic and has a pronounced wet season between September and March. Sampling encompassed a range of topographic features, such as grassland on freely draining, gently inclined or steep slopes and depressions containing bogs, over a 3 ha ridge to basin transition. Monthly sampling was carried out between January 2011 and June 2013 to investigate seasonal variability in methane fluxes. Intensive sampling campaigns were conducted to investigate spatial and short-term variations on a daily basis in two nine-day campaigns during wet and dry season. The site was a net source of methane to the atmosphere during the period of study. Methane fluxes were dominated by emissions from bogs, whereas, freely draining grassland exhibited weak source or marginal sink activity. Temporal variations were most notable at

  13. Solvent content and dentin bond strengths using water-wet, ethanol-wet and deproteinization bonding techniques.

    Science.gov (United States)

    Faria-e-Silva, André Luis; Araújo, José Everton; Rocha, Gilliane Pereira; de Oliveira, Aline da Silva; de Moraes, Rafael Ratto

    2013-01-01

    To evaluate the impact of solvent content in two-step, etch-and-rinse adhesives on the dentin bond strengths obtained via water-wet, ethanol-wet or deproteinization techniques. A model photocurable Bis-GMA/HEMA blend was diluted in ethanol (7.5, 15 or 30 mass%) or acetone (15, 30 or 60 mass%) (low, medium or high solvent content, respectively). Viscosity of the solutions was measured with an oscillatory viscometer and data analyzed using ANOVA on Ranks (5%). Dentin bond strengths were evaluated using microshear bond test. After acid-etching and rinsing, the dentin was kept wet (water-wet), treated with ascending ethanol concentrations (ethanol-wet) or with 10% NaOCl solution (deproteinization). Composite cylinders built-up on the surfaces for the microshear test. Data from each bonding technique were submitted to two-way ANOVA and Fisher's LSD method (5%). Failure modes were classified under magnification and data analyzed using chi-square tests (5%). Viscosity of ethanol-based agents was remarkably higher than acetone solutions. For the water-wet technique, lower bond strength was observed for the low compared with medium and high ethanol contents. For the ethanol-wet technique, the bond strength for both solvents types was low dentin bond strengths for the conventional and ethanol bonding techniques.

  14. Shedding of ash deposits

    DEFF Research Database (Denmark)

    Zbogar, Ana; Frandsen, Flemming; Jensen, Peter Arendt

    2009-01-01

    Ash deposits formed during fuel thermal conversion and located on furnace walls and on convective pass tubes, may seriously inhibit the transfer of heat to the working fluid and hence reduce the overall process efficiency. Combustion of biomass causes formation of large quantities of troublesome...... ash deposits which contain significant concentrations of alkali, and earth-alkali metals. The specific composition of biomass deposits give different characteristics as compared to coal ash deposits, i.e. different physical significance of the deposition mechanisms, lower melting temperatures, etc....... Low melting temperatures make straw ashes especially troublesome, since their stickiness is higher at lower temperatures, compared to coal ashes. Increased stickiness will eventually lead to a higher collection efficiency of incoming ash particles, meaning that the deposit may grow even faster...

  15. Modeling and mapping of atmospheric mercury deposition in adirondack park, new york.

    Directory of Open Access Journals (Sweden)

    Xue Yu

    Full Text Available The Adirondacks of New York State, USA is a region that is sensitive to atmospheric mercury (Hg deposition. In this study, we estimated atmospheric Hg deposition to the Adirondacks using a new scheme that combined numerical modeling and limited experimental data. The majority of the land cover in the Adirondacks is forested with 47% of the total area deciduous, 20% coniferous and 10% mixed. We used litterfall plus throughfall deposition as the total atmospheric Hg deposition to coniferous and deciduous forests during the leaf-on period, and wet Hg deposition plus modeled atmospheric dry Hg deposition as the total Hg deposition to the deciduous forest during the leaf-off period and for the non-forested areas year-around. To estimate atmospheric dry Hg deposition we used the Big Leaf model. The average atmospheric Hg deposition to the Adirondacks was estimated as 17.4 [Formula: see text]g m[Formula: see text] yr[Formula: see text] with a range of -3.7-46.0 [Formula: see text]g m[Formula: see text] yr[Formula: see text]. Atmospheric Hg dry deposition (370 kg yr[Formula: see text] was found to be more important than wet deposition (210 kg yr[Formula: see text] to the entire Adirondacks (2.4 million ha. The spatial pattern showed a large variation in atmospheric Hg deposition with scattered areas in the eastern Adirondacks having total Hg deposition greater than 30 μg m(-2 yr(-1, while the southwestern and the northern areas received Hg deposition ranging from 25-30 μg m(-2 yr(-1.

  16. Infiltration in unsaturated layered fluvial deposits at Rio Bravo : photo essay and data summary.

    Energy Technology Data Exchange (ETDEWEB)

    Brainard, James Robert; Glass, Robert John, Jr.

    2007-08-01

    An infiltration and dye transport experiment was conducted to visualize flow and transport processes in a heterogeneous, layered, sandy-gravelly fluvial deposit adjacent to Rio Bravo Boulevard in Albuquerque, NM. Water containing red dye followed by blue-green dye was ponded in a small horizontal zone ({approx}0.5 m x 0.5 m) above a vertical outcrop ({approx}4 m x 2.5 m). The red dye lagged behind the wetting front due to slight adsorption thus allowing both the wetting front and dye fronts to be observed in time at the outcrop face. After infiltration, vertical slices were excavated to the midpoint of the infiltrometer exposing the wetting front and dye distribution in a quasi three-dimensional manner. At small-scale, wetting front advancement was influenced by the multitude of local capillary barriers within the deposit. However at the scale of the experiment, the wetting front appeared smooth with significant lateral spreading {approx} twice that in the vertical, indicating a strong anisotropy due to the pronounced horizontal layering. The dye fronts exhibited appreciably more irregularity than the wetting front, as well as the influence of preferential flow features (a fracture) that moved the dye directly to the front, bypassing the fresh water between.

  17. SAFARI 2000 PAR Measurements, Kalahari Transect, Botswana, Wet Season 2000

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: Ceptometer data from a Decagon AccuPAR (Model PAR-80) were collected at four sites in Botswana during the SAFARI 2000 Kalahari Transect Wet Season Campaign...

  18. SAFARI 2000 PAR Measurements, Kalahari Transect, Botswana, Wet Season 2000

    Data.gov (United States)

    National Aeronautics and Space Administration — Ceptometer data from a Decagon AccuPAR (Model PAR-80) were collected at four sites in Botswana during the SAFARI 2000 Kalahari Transect Wet Season Campaign (March,...

  19. The Geologic Evidence for a Warm and Wet Early Mars

    Science.gov (United States)

    Craddock, R. A.; Irwin, R. P.; Howard, A. D.; Morgan, A. M.

    2017-10-01

    The geologic evidence supporting a warm and wet climate on early Mars is presented. The case against an "icy highlands" scenario is also made. Climate models are converging to a solution, but any theoretical data must explain the empirical data.

  20. Advanced Wet Tantalum Capacitors: Design, Specifications and Performance

    Science.gov (United States)

    Teverovsky, Alexander

    2017-01-01

    Insertion of new types of commercial, high volumetric efficiency wet tantalum capacitors in space systems requires reassessment of the existing quality assurance approaches that have been developed for capacitors manufactured to MIL-PRF-39006 requirements. The specifics of wet electrolytic capacitors is that leakage currents flowing through electrolyte can cause gas generation resulting in building up of internal gas pressure and rupture of the case. The risk associated with excessive leakage currents and increased pressure is greater for high value advanced wet tantalum capacitors, but it has not been properly evaluated yet. This presentation gives a review of specifics of the design, performance, and potential reliability risks associated with advanced wet tantalum capacitors. Problems related to setting adequate requirements for DPA, leakage currents, hermeticity, stability at low and high temperatures, ripple currents for parts operating in vacuum, and random vibration testing are discussed. Recommendations for screening and qualification to reduce risks of failures have been suggested.

  1. Bioaccumulation of heavy metals in two wet retention ponds

    DEFF Research Database (Denmark)

    Søberg, Laila C.; Vollertsen, Jes; Blecken, Godecke-Tobias

    2016-01-01

    Metal accumulation in stormwater ponds may contaminate the inhabiting fauna, thus jeopardizing their ecosystem servicing function. We evaluated bioaccumulation of metals in natural fauna and caged mussel indicator organisms in two wet retention ponds. Mussel cages were distributed throughout...

  2. In silico and wet lab approaches to study transcriptional regulation

    NARCIS (Netherlands)

    Hestand, Matthew Scott

    2010-01-01

    Gene expression is a complicated process with multiple types of regulation, including binding of proteins termed transcription factors. This thesis looks at transcription factors and transcription factor binding site discovery through computational predictions and wet lab work to better elucidate

  3. Combined wet oxidation and alkaline hydrolysis of polyvinylchloride

    DEFF Research Database (Denmark)

    Sørensen, E.; Bjerre, A.B.

    1992-01-01

    In view of the widespread aversion to burning polyvinylchloride (PVC) together with municipal waste, we have attempted an alternative approach to its decomposition. This paper describes a combined wet oxidation/alkaline hydrolysis yielding water soluble, biodegradable products. Experiments were...

  4. Simulations of tropical rainforest albedo: is canopy wetness important?

    National Research Council Canada - National Science Library

    Silvia N.M. Yanagi; Marcos H. Costa

    2011-01-01

    .... Therefore, it was investigated the role of canopy wetness on the simulated albedo of a tropical rainforest by modifying the IBIS canopy radiation transfer code to incorporate the effects of canopy...

  5. The Forensic and Legal Implications of Water, Wet, or Fry

    National Research Council Canada - National Science Library

    Susan M. Chlebowski; Cecilia Leonard

    2012-01-01

    ...), has several names, such as water, wet, illy, and fry. Individuals who commit crimes under the influence of this substance are often violent and may appear psychotic, with symptoms resembling schizophrenia or delirium...

  6. Characterization of silver nanoparticles prepared by wet chemical ...

    African Journals Online (AJOL)

    Characterization of silver nanoparticles prepared by wet chemical method and their antibacterial and cytotoxicity activities. Manal A Awad, Awatif A Hendi, Khalid MO Ortashi, Reem A Alotaibi, Maha Sh Sharafeldin ...

  7. Regulated wet nursing: managed care or organized crime?

    National Research Council Canada - National Science Library

    Obladen, Michael

    2012-01-01

    .... When artificial feeding lost its threat thanks to sewage disposal, improved plumbing, the introduction of rubber teats, cooling facilities and commercial formula, wet nursing declined towards the end of the 19th century.

  8. Wet cooling towers: rule-of-thumb design and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Leeper, Stephen A. [EG and G Idaho, Inc., Idaho Falls, ID (United States)

    1981-07-01

    A survey of wet cooling tower literature was performed to develop a simplified method of cooling tower design and simulation for use in power plant cycle optimization. The theory of heat exchange in wet cooling towers is briefly summarized. The Merkel equation (the fundamental equation of heat transfer in wet cooling towers) is presented and discussed. The cooling tower fill constant (Ka) is defined and values derived. A rule-of-thumb method for the optimized design of cooling towers is presented. The rule-of-thumb design method provides information useful in power plant cycle optimization, including tower dimensions, water consumption rate, exit air temperature, power requirements and construction cost. In addition, a method for simulation of cooling tower performance at various operating conditions is presented. This information is also useful in power plant cycle evaluation. Using the information presented, it will be possible to incorporate wet cooling tower design and simulation into a procedure to evaluate and optimize power plant cycles.

  9. SAFARI 2000 Leaf Spectral Measurements, Kalahari Transect, Wet Season 2000

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: The Boston University team collected several data sets along the Kalahari Transect during the SAFARI 2000 wet season field campaign between March 3 and...

  10. SAFARI 2000 Leaf Spectral Measurements, Kalahari Transect, Wet Season 2000

    Data.gov (United States)

    National Aeronautics and Space Administration — The Boston University team collected several data sets along the Kalahari Transect during the SAFARI 2000 wet season field campaign between March 3 and March 18,...

  11. Advance of Wetting Front in Silt Loam Soil

    Directory of Open Access Journals (Sweden)

    Mohamed Mahmood

    2013-04-01

    Full Text Available Under drip irrigation , the plant's root is concentrated inside the wetted bulb (region. Thus, the development of these roots and the plant production are greatly affected by the wetting pattern. Therefore, the wetting pattern of soil under drip irrigation must be taken into consideration in the design of drip irrigation system for both single dripping source or multi-overlapping wetting patterns of dripping water sources.2The aim of this study is to evaluate the effect of initial water content of the soil and spacing between two adjacent dripping sources with different flow rate on the movement of the wetting front.This study included 16 tests for monitoring the advancement of the wetting front with time during and after the water application phase. The water advance and water distribution measurement are carried out for two cases of the soil profile: for the first case with initial volumetric water content of 4.08% and for the second case with initial volumetric water content of 12.24%. Two spacing between the emitter were tested 25cm and 50 cm using application flow rates of 0.606, 1.212, 1.818, and 2.424 cm3 /min/cm to show the combined effect of spacing and flow rate on the performance of two adjacent emitter.The study proposed a method for determining the spacing between the two emitting sources , the water application rate and watering time. The proposed method depends on a wetted zone whose depth is equal to the root zone depth with a values equals to the maximum vertical advance of the wetting front underneath the drip line at time when this depth is equal to the depth of wetting at mid­point between the drip line. the study revealed that both the vertical water advance in soil underneath the emitter and the horizontal advance of the wetting front is larger than those in the case of single emitter.Furthermore, the vertical water advance increases with the decrease spacing between the two drip lines. Also, the horizontal advance of the

  12. Surface Tension Triggered Wetting and Point of Care Sensor Design.

    Science.gov (United States)

    Falde, Eric J; Yohe, Stefan T; Grinstaff, Mark W

    2015-08-05

    Rapid, simple, and inexpensive point-of-care (POC) medical tests are of significant need around the world. The transition between nonwetting and wetted states is used to create instrument-free surface tension sensors for POC diagnosis, using a layered electrospun mesh with incorporated dye to change color upon wetting. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Evaluation of the effectiveness of coal and mine dust wetting

    Directory of Open Access Journals (Sweden)

    Krzysztof Cybulski

    2015-01-01

    This paper presents a method to evaluate the effectiveness of coal or mine dust's moistening conducted with the use of water solutions of wetting agents in order to deprive the dust of its volatility, is based on the method of measurement of time of complete moistening of that dust's one-gram samples with the use of “pure” water or water solutions of the particular wetting agent.

  14. Modeling Reactive Wetting when Inertial Effects are Dominant

    OpenAIRE

    Wheeler, Daniel; Warren, James A.; Boettinger, William J.

    2010-01-01

    Recent experimental studies of molten metal droplets wetting high temperature reactive substrates have established that the majority of triple-line motion occurs when inertial effects are dominant. In light of these studies, this paper investigates wetting and spreading on reactive substrates when inertial effects are dominant using a thermodynamically derived, diffuse interface model of a binary, three-phase material. The liquid-vapor transition is modeled using a van der Waals diffuse inter...

  15. [Hemicorporectomy with double barreled wet colostomy: an extremely rare procedure].

    Science.gov (United States)

    Ricci, Marco Antonio; Duarte, Enio Lucio Coelho; Souza, Renato Costa Amaral; Albuquerque-Peres, Carlos Michel; Guimaraes, Gustavo Cardoso; Lopes, Ademar

    2009-12-01

    The Hemicorporectomy associated to Double-barreled wet colostomy is a high complex and heroic procedure and is to be used only exceptionally, when it is the last resource for treating locally advanced pelvic diseases in the absence of evidences of distant metastasis. We retrospectively analyzed the surgical technical details and the results from a hemicorporectomy with double-barreled wet colostomy in a single surgical time in a case of epidermoide carcinoma from a coetaneous pressure ulcer.

  16. Development of Wet Noodles Based on Cassava Flour

    OpenAIRE

    Abidin, Akhmad Z; Devi, Cinantya; Adeline, A

    2013-01-01

    Cassava is one of Indonesia’s original commodities and contains good nutrition and has high productivity and a relatively low price. Cassava flour has a high potential as a substitute for imported wheat flour that is widely used in noodle production. The main purpose of this research was to develop wet noodles from cassava flour that can compete with wet noodles from wheat flour. The research consisted of experiments with several variations of composition and production method for producing c...

  17. Microbial community composition of transiently wetted Antarctic Dry Valley soils

    Directory of Open Access Journals (Sweden)

    Thomas D. Neiderberger

    2015-01-01

    Full Text Available During the summer months, wet (hyporheic soils associated with ephemeral streams and lake edges in the Antarctic Dry Valleys (DV become hotspots of biological activity and are hypothesized to be an important source of carbon and nitrogen for arid DV soils. Recent research in the DV has focused on the geochemistry and microbial ecology of lakes and arid soils, with substantially less information being available on hyporheic soils. Here we determined the unique properties of hyporheic microbial communities, resolved their relationship to environmental parameters and to compared them to archetypal arid DV soils. Generally, pH increased and chlorophyll a concentrations decreased along transects from wet to arid soils (9.0 to ~7.0 for pH and ~0.8 to ~ 5 µg/cm3 for chlorophyll a, respectively. Soil water content decreased to below ~3% in the arid soils. Community fingerprinting-based principle component analyses revealed that bacterial communities formed distinct clusters specific to arid and wet soils; however, eukaryotic communities that clustered together did not have similar soil moisture content nor did they group together based on sampling location. Collectively, rRNA pyrosequencing indicated a considerably higher abundance of Cyanobacteria in wet soils and a higher abundance of Acidobacterial, Actinobacterial, Deinococcus/Thermus, Bacteroidetes, Firmicutes, Gemmatimonadetes, Nitrospira and Planctomycetes in arid soils. The two most significant differences at the genus level were Gillisia signatures present in arid soils and chloroplast signatures related to Streptophyta that were common in wet soils. Fungal dominance was observed in arid soils and Viridplantae were more common in wet soils. This research represents an in-depth characterization of microbial communities inhabiting wet DV soils. Results indicate that the repeated wetting of hyporheic zones has a profound impact on the bacterial and eukaryotic communities inhabiting in these areas.

  18. Hijama (Wet Cupping or Dry Cupping) for Diabetes Treatment

    OpenAIRE

    Vakilinia, Seyed Reza; Bayat, Davood; Asghari, Majid

    2016-01-01

    Background: Diabetes is known as one of the most common diseases in the world and its treatment is one of the most important healthcare issues. Consequently, different treatment methods of complementary medicine and recent medicine have been used by scientific communities to control and predict the disease. This article considered the effects of dry cupping and wet cupping, based on traditional medicine and recent studies. Methods: At first, the benefits of dry cupping and wet cupping were ta...

  19. Human skin wetness perception: psychophysical and neurophysiological bases

    Science.gov (United States)

    Filingeri, Davide; Havenith, George

    2015-01-01

    The ability to perceive thermal changes in the surrounding environment is critical for survival. However, sensing temperature is not the only factor among the cutaneous sensations to contribute to thermoregulatory responses in humans. Sensing skin wetness (i.e. hygrosensation) is also critical both for behavioral and autonomic adaptations. Although much has been done to define the biophysical role of skin wetness in contributing to thermal homeostasis, little is known on the neurophysiological mechanisms underpinning the ability to sense skin wetness. Humans are not provided with skin humidity receptors (i.e., hygroreceptors) and psychophysical studies have identified potential sensory cues (i.e. thermal and mechanosensory) which could contribute to sensing wetness. Recently, a neurophysiological model of human wetness sensitivity has been developed. In helping clarifying the peripheral and central neural mechanisms involved in sensing skin wetness, this model has provided evidence for the existence of a specific human hygrosensation strategy, which is underpinned by perceptual learning via sensory experience. Remarkably, this strategy seems to be shared by other hygroreceptor-lacking animals. However, questions remain on whether these sensory mechanisms are underpinned by specific neuromolecular pathways in humans. Although the first study on human wetness perception dates back to more than 100 years, it is surprising that the neurophysiological bases of such an important sensory feature have only recently started to be unveiled. Hence, to provide an overview of the current knowledge on human hygrosensation, along with potential directions for future research, this review will examine the psychophysical and neurophysiological bases of human skin wetness perception. PMID:27227008

  20. Hijama (Wet Cupping or Dry Cupping) for Diabetes Treatment.

    Science.gov (United States)

    Vakilinia, Seyed Reza; Bayat, Davood; Asghari, Majid

    2016-05-01

    Diabetes is known as one of the most common diseases in the world and its treatment is one of the most important healthcare issues. Consequently, different treatment methods of complementary medicine and recent medicine have been used by scientific communities to control and predict the disease. This article considered the effects of dry cupping and wet cupping, based on traditional medicine and recent studies. At first, the benefits of dry cupping and wet cupping were taken from some original books of Iranian traditional medicine, such as Canon of Medicine, Kholasat-al-hekma, Tib-e-Akbari and Exir-e-Azam. Then, the information about scientific articles was obtained by studying some of the Iranian traditional medicine journals and searching through PubMed, SID and Google Scholar. In traditional medicine, Hijama is divided into two kinds, namely wet cupping (with sharat, with incision, and blood giving) and dry cupping (without sharat, without incision). Dry cupping causes organ blood absorption, organ warming, and loss of organ humidity. The texts of Iranian traditional medicine refer to the Ziabites disease that its symptoms are like diabetes. This disease is divided into two types including warm and cold ziabetes. The treatments that are recommended for both types are dry cupping for cold ziabetes and wet cupping for warm ziabetes. In addition, according to scientific studies, dry cupping and wet cupping have been recommended for diabetes treatment. Dry cupping and wet cupping can be introduced as the complementary treatment methods beside other treatment methods.

  1. Development of Wet Noodles Based on Cassava Flour

    Directory of Open Access Journals (Sweden)

    Akhmad Z. Abidin

    2013-04-01

    Full Text Available Cassava is one of Indonesia’s original commodities and contains good nutrition and has high productivity and a relatively low price. Cassava flour has a high potential as a substitute for imported wheat flour that is widely used in noodle production. The main purpose of this research was to develop wet noodles from cassava flour that can compete with wet noodles from wheat flour. The research consisted of experiments with several variations of composition and production method for producing cassava flour-based wet noodles. The best result was then examined for its nutritional value, economical value, and market response, and also a comparison was made between the prepared wet noodles and the standard noodles made from wheat flour. The analysis was based on five characteristics: taste, texture, chewiness, aroma, and appearance. Relations between these characteristics with composition, materials used, and methods applied are discussed. The developed cassava flour-based wet noodle meets physical, nutritional, and economical standards. Raw materials of the noodle were cassava flour and a wheat flour composite with a 5:1 ratio, egg, gluten, soda-ash, water, and vegetable oil, while the process was completed in multiple stages. Market response showed that the cassava flour-based wet noodles were 80% similar to wheat-flour noodles.

  2. Lichen-based critical loads for atmospheric nitrogen deposition in Western Oregon and Washington Forests, USA.

    Science.gov (United States)

    Geiser, Linda H; Jovan, Sarah E; Glavich, Doug A; Porter, Matthew K

    2010-07-01

    Critical loads (CLs) define maximum atmospheric deposition levels apparently preventative of ecosystem harm. We present first nitrogen CLs for northwestern North America's maritime forests. Using multiple linear regression, we related epiphytic-macrolichen community composition to: 1) wet deposition from the National Atmospheric Deposition Program, 2) wet, dry, and total N deposition from the Communities Multi-Scale Air Quality model, and 3) ambient particulate N from Interagency Monitoring of Protected Visual Environments (IMPROVE). Sensitive species declines of 20-40% were associated with CLs of 1-4 and 3-9 kg N ha(-1)y(-1) in wet and total deposition. CLs increased with precipitation across the landscape, presumably from dilution or leaching of depositional N. Tight linear correlation between lichen and IMPROVE data suggests a simple screening tool for CL exceedance in US Class I areas. The total N model replicated several US and European lichen CLs and may therefore be helpful in estimating other temperate-forest lichen CLs. Published by Elsevier Ltd.

  3. European and Mediterranean mercury modelling: Local and long-range contributions to the deposition flux

    Science.gov (United States)

    Gencarelli, Christian N.; De Simone, Francesco; Hedgecock, Ian M.; Sprovieri, Francesca; Yang, Xin; Pirrone, Nicola

    2015-09-01

    Mercury (Hg) is a global pollutant that is known to have adverse effects on human health, and most human exposure to toxic methylmercury is through fish consumption. Soluble Hg compounds in the marine environment can be methylated in the water column and enter the base of the food chain. Atmospheric deposition is the most important pathway by which Hg enters marine ecosystems. The atmospheric chemistry of Hg has been simulated over Europe and the Mediterranean for the year 2009, using the WRF/Chem model and employing two different gas phase Hg oxidation mechanisms. The contributions to the marine deposition flux from dry deposition, synoptic scale wet deposition and convective wet deposition have been determined. The Hg deposition fluxes resulting from transcontinental transport and local/regional emission sources has been determined using both Br/BrO and O3/OH atmospheric oxidation mechanisms. The two mechanisms give significantly different annual deposition fluxes (129 Mg and 266 Mg respectively) over the modelling domain. Dry deposition is more significant using the O3/OH mechanism, while proportionally convective wet deposition is enhanced using the Br/BrO mechanism. The simulations using the Br/BrO oxidation compared best with observed Hg fluxes in precipitation. Local/regional Hg emissions have the most impact within the model domain during the summer. A comparison of simulations using the 2005 and 2010 AMAP/UNEP Hg emission inventories show that although there is a decrease of 33% in anthropogenic emissions between the two reference years, the total simulated deposition in the regions diminishes by only 12%. Simulations using the 2010 inventory reproduce observations somewhat better than those using the 2005 inventory for 2009.

  4. External radiation assessment in a wet phosphoric acid production plant

    Energy Technology Data Exchange (ETDEWEB)

    Bolivar, J.P.; Perez-Moreno, J.P. [Dept. Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, 21012 Huelva (Spain); Mas, J.L. [Dept. Fisica Aplicada I, Escuela Universitaria Politecnica, Universidad de Sevilla, 41012 Sevilla (Spain)], E-mail: ppmasb@us.es; Martin, J.E.; San Miguel, E.G. [Dept. Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, 21012 Huelva (Spain); Garcia-Tenorio, R. [Dept. Fisica Aplicada II, Escuela Tecnica Superior de Arquitectura, Universidad de Sevilla, 41012 Sevilla (Spain)

    2009-10-15

    The factories dedicated to the production of phosphoric acid by the so-called wet acid method are usually considered typical NORM industries, because the phosphate rock used as raw material usually contains high concentrations of {sup 238}U-series radionuclides. The magnitude and behaviour of the radionuclides involved in the production process revealed the need to determine its dosimetric impact on workers. This work aims to partially compensate this lack of knowledge through the determination of external effective dose rates at different zones in the process at a typical plant located in the southwest of Spain. To this end, two dosimetric sampling campaigns have been carried out at this phosphoric acid production plant. The first sampling was carried out when phosphate rocks originating in Morocco were processed, and the second one when phosphate rock processed came from the Kola Peninsula (Russia Federation). This differentiation was necessary because the activity concentrations are almost one order of magnitude higher in Moroccan phosphate rock than in Kola phosphate rock. The results obtained have reflected external dose rate enhancements as high as 1.4 {mu}Sv h{sup -1} (i.e., up to thirty times the external exposition due to radionuclides in unperturbed soils) at several points in the facility, particularly where the digested rock (pulp) is filtered. However, the most problematic points are characterised by a small occupation factor. That means that the increment in the annual effective external gamma dose received by the most-exposed worker is clearly below 1 mSv (European Commission limit for the general population) under normal production. Nevertheless, special care in the design and schedule of cleaning and maintaining work in the areas with high doses should be taken in order to avoid any possibility of exceeding the previously mentioned general population limit. In addition, the results of the dosimetric campaign showed no clear correlation between {sup

  5. Biomimetic wet-stable fibres via wet spinning and diacid-based crosslinking of collagen triple helices

    CERN Document Server

    Arafat, M Tarik; Yin, Jie; Wood, David J; Russell, Stephen J

    2015-01-01

    One of the limitations of electrospun collagen as bone-like fibrous structure is the potential collagen triple helix denaturation in the fibre state and the corresponding inadequate wet stability even after crosslinking. Here, we have demonstrated the feasibility of accomplishing wet-stable fibres by wet spinning and diacid-based crosslinking of collagen triple helices, whereby fibre ability to act as bone-mimicking mineralisation system has also been explored. Circular dichroism (CD) demonstrated nearly complete triple helix retention in resulting wet-spun fibres, and the corresponding chemically crosslinked fibres successfully preserved their fibrous morphology following 1-week incubation in phosphate buffer solution (PBS). The presented novel diacid-based crosslinking route imparted superior tensile modulus and strength to the resulting fibres indicating that covalent functionalization of distant collagen molecules is unlikely to be accomplished by current state-of-the-art carbodiimide-based crosslinking. ...

  6. Temporal network epidemiology

    CERN Document Server

    Holme, Petter

    2017-01-01

    This book covers recent developments in epidemic process models and related data on temporally varying networks. It is widely recognized that contact networks are indispensable for describing, understanding, and intervening to stop the spread of infectious diseases in human and animal populations; “network epidemiology” is an umbrella term to describe this research field. More recently, contact networks have been recognized as being highly dynamic. This observation, also supported by an increasing amount of new data, has led to research on temporal networks, a rapidly growing area. Changes in network structure are often informed by epidemic (or other) dynamics, in which case they are referred to as adaptive networks. This volume gathers contributions by prominent authors working in temporal and adaptive network epidemiology, a field essential to understanding infectious diseases in real society.

  7. Modelling and investigation of partial wetting surfaces for drop dynamics using lattice Boltzmann method

    Science.gov (United States)

    Pravinraj, T.; Patrikar, Rajendra

    2017-07-01

    Partial wetting surfaces and its influence on the droplet movement of micro and nano scale being contemplated for many useful applications. The dynamics of the droplet usually analyzed with a multiphase lattice Boltzmann method (LBM). In this paper, the influence of partial wetting surface on the dynamics of droplet is systematically analyzed for various cases. Splitting of droplets due to chemical gradient of the surface is studied and analyses of splitting time for various widths of the strips for different Weber numbers are computed. With the proposed model one can tune the splitting volume and time by carefully choosing a strip width and droplet position. The droplet spreading on chemically heterogeneous surfaces shows that the spreading can be controlled not only by parameters of Weber number but also by tuning strip width ratio. The transportation of the droplet from hydrophobic surface to hydrophilic surface due to chemical gradient is simulated and analyzed using our hybrid thermodynamic-image processing technique. The results prove that with the progress of time the surface free energy decreases with increase in spreading area. Finally, the transportation of a droplet on microstructure gradient is demonstrated. The model explains the temporal behaviour of droplet during the spreading, recoiling and translation along with tracking of contact angle hysteresis phenomenon.

  8. Postfact phenomena of the wet-steam flow electrization in turbines

    Science.gov (United States)

    Tarelin, A. A.

    2017-11-01

    Physical processes occurring in a turbine with natural electrization of a humidity-steam flow and their effect on efficiency and reliability of the turbine operation has been considered. Causes of the electrical potential occurrence on a rotor shaft are analyzed. The wet steam's electrization exposure on the electrical potential that is one of the major factors of bearings' electroerosion has been demonstrated on the full-scale installation. Hydrogen formation in wheelspace of the turbine as a result of electrochemical processes and electric field exposure of the space charge has been considered. Hydrogen concentration dependence on a volume charge density in the steam flow has been determined. It is stated that the processes occurring behind the final stage of wet-steam turbines are similar to the ones in elaerosol ectrostatic generators. It has been demonstrated that this phenomenon causes the flow's temporal inhibition and starts pulsations. These factors' impact on power loss of the turbine has been evaluated and recommendations for their elimination have been offered. It has been determined that motions of charged drops can cause self-maintained discharges inside of the flow and between the flow and grounded surfaces that are accompanied by electromagnetic radiation of the wide spectrum. The integrated studies have shown that physical phenomena occurring due to natural electrization negatively affect efficiency and reliability of the turbine operation. Practical recommendations allowing one to minimize the negative effects of the flow natural electrization process have been offered.

  9. Vivienda temporal para refugiados

    OpenAIRE

    Amonarraiz Gutiérrez, Ana

    2015-01-01

    El proyecto se centra en el diseño y desarrollo de un espacio destinado a vivienda temporal para dar hogar a personas que han perdido su casa. Este tipo de vivienda es fundamental dentro del proceso de recuperación post-desastre ya que la construcción inmediata de viviendas permanentes es utópica. El objetivo principal es la construcción de una vivienda temporal formada por elementos prefabricados, logrando así una mayor rapidez en su montaje. Esto también permitirá que cualquier component...

  10. Measurements and Modeling to Enhance Estimates of NH3 Total Deposition

    Science.gov (United States)

    Values for the total (wet + dry) deposition of ammonia are needed as input to nitrogen budget studies and ecological assessments. Concentrations of ammonia are measured at NADP’s Ammonia Monitoring Network (AMoN) sites. Research is focusing on the use of the concentration...

  11. Reagent deposition for rapid multiplex pathogen identification in human blood culture samples

    DEFF Research Database (Denmark)

    Mogensen, Klaus Bo; Machado, Ana Manuel; Dufva, Martin

    2014-01-01

    viewed in a dual-color microscope configuration. The test takes 20-30 min to perform. In order to lower the cost of the test, rapid automated reagent deposition is needed. Here, ultrasonic spray coating of polyvinyl alcohol/PNA-probes on microscope glass slides is presented. Different wetting regimes...

  12. Fabrication of electro-wetting liquid lenticular lens by using diffuser

    Science.gov (United States)

    Sim, Jee Hoon; Kim, Junoh; Kim, Cheoljoong; Shin, Dooseub; Lee, Junsik; Koo, Gyo Hyun; Won, Yong Hyub

    2017-02-01

    Liquid lenticular multi-view system has great potential of three dimensional image realization. This paper aims to introduce a novel fabrication method of electro-wetting liquid lenticular lens using diffuser. The liquid lenticular device consists of a Ultraviolet (UV) adhesive chamber, two immiscible liquids and a sealing plate. The diffuser makes UV light spread slantly not directly to negative photoresist on a glass substrate. In this process, Su-8, the suitable material to fabricate a structure in high stature, is selected for negative photoresist. After forming a Su-8 chamber, the UV adhesive chamber is made through a PDMS sub-chamber that is made from the Su-8 chamber. As such, this research shows a result of a liquid lenticular lens having slanted side walls with an angle of 75 degrees. The UV adhesive chamber having slanted side walls is more advantageous for electro-wetting effect achieving high diopter than the chamber having vertical side walls. After that, gold is evaporated for electrode, and Parylene C and Teflon AF1600 is deposited for dielectric and hydrophobic layer respectively. For two immiscible liquids, DI water and a blend of 1-Chloronaphthalene and Dodecane with specific portions are used. Two immiscible liquids are injected in underwater environment and a glass that is coated with ITO on one side is sealed by UV adhesive. The completed tunable lenticular lens can switch two and three dimensional images by using electro-wetting principle that changes surface tensions by applying voltage. Also, dioptric power and response time of the liquid lenticular lens array are measured.

  13. Biomimetic thin film deposition

    Energy Technology Data Exchange (ETDEWEB)

    Rieke, P.R.; Graff, G.E.; Campbell, A.A.; Bunker, B.C.; Baskaran, S.; Song, L.; Tarasevich, B.J.; Fryxell, G.E.

    1995-09-01

    Biological mineral deposition for the formation of bone, mollusk shell and other hard tissues provides materials scientists with illustrative materials processing strategies. This presentation will review the key features of biomineralization and how these features can be of technical importance. We have adapted existing knowledge of biomineralization to develop a unique method of depositing inorganic thin films and coating. Our approach to thin film deposition is to modify substrate surfaces to imitate the proteins found in nature that are responsible for controlling mineral deposition. These biomimetic surfaces control the nucleation and growth of the mineral from a supersaturated aqueous solution. This has many processing advantages including simple processing equipment, environmentally benign reagents, uniform coating of highly complex shapes, and enhanced adherence of coating. Many different types of metal oxide, hydroxide, sulfide and phosphate materials with useful mechanical, optical, electronic and biomedical properties can be deposited.

  14. Stratiform chromite deposit model

    Science.gov (United States)

    Schulte, Ruth F.; Taylor, Ryan D.; Piatak, Nadine M.; Seal, Robert R.

    2010-01-01

    Stratiform chromite deposits are of great economic importance, yet their origin and evolution remain highly debated. Layered igneous intrusions such as the Bushveld, Great Dyke, Kemi, and Stillwater Complexes, provide opportunities for studying magmatic differentiation processes and assimilation within the crust, as well as related ore-deposit formation. Chromite-rich seams within layered intrusions host the majority of the world's chromium reserves and may contain significant platinum-group-element (PGE) mineralization. This model of stratiform chromite deposits is part of an effort by the U.S. Geological Survey's Mineral Resources Program to update existing models and develop new descriptive mineral deposit models to supplement previously published models for use in mineral-resource and mineral-environmental assessments. The model focuses on features that may be common to all stratiform chromite deposits as a way to gain insight into the processes that gave rise to their emplacement and to the significant economic resources contained in them.

  15. Estimating seasonal evapotranspiration from temporal satellite images

    Science.gov (United States)

    Singh, Ramesh K.; Liu, Shu-Guang; Tieszen, Larry L.; Suyker, Andrew E.; Verma, Shashi B.

    2012-01-01

    Estimating seasonal evapotranspiration (ET) has many applications in water resources planning and management, including hydrological and ecological modeling. Availability of satellite remote sensing images is limited due to repeat cycle of satellite or cloud cover. This study was conducted to determine the suitability of different methods namely cubic spline, fixed, and linear for estimating seasonal ET from temporal remotely sensed images. Mapping Evapotranspiration at high Resolution with Internalized Calibration (METRIC) model in conjunction with the wet METRIC (wMETRIC), a modified version of the METRIC model, was used to estimate ET on the days of satellite overpass using eight Landsat images during the 2001 crop growing season in Midwest USA. The model-estimated daily ET was in good agreement (R2 = 0.91) with the eddy covariance tower-measured daily ET. The standard error of daily ET was 0.6 mm (20%) at three validation sites in Nebraska, USA. There was no statistically significant difference (P > 0.05) among the cubic spline, fixed, and linear methods for computing seasonal (July–December) ET from temporal ET estimates. Overall, the cubic spline resulted in the lowest standard error of 6 mm (1.67%) for seasonal ET. However, further testing of this method for multiple years is necessary to determine its suitability.

  16. Wet-snow avalanche interaction with a deflecting dam: field observations and numerical simulations in a case study

    Directory of Open Access Journals (Sweden)

    B. Sovilla

    2012-05-01

    Full Text Available In avalanche-prone areas, deflecting dams are widely used to divert avalanches away from endangered objects. In recent years, their effectiveness has been questioned when several large and multiple avalanches have overrun such dams.

    In 2008, we were able to observe a large wet-snow avalanche, characterized by an high water content, that interacted with a deflecting dam and overflowed it at its lower end. To evaluate the dam's performance, we carried out an airborne laser scanning campaign immediately after the avalanche. This data, together with a video sequence made during the avalanche descent, provided a unique data set to study the dynamics of a wet dense snow avalanche and its flow behavior along a deflecting dam.

    To evaluate the effect of the complex flow field of the avalanche along the dam and to provide a basis for discussion of the residual risk, we performed numerical simulations using a two-dimensional dense snow avalanche dynamics model with entrainment.

    In comparison to dry dense snow avalanches, we found that wet-snow avalanches, with high water content, seem to be differently influenced by the local small-scale topography roughness. Rough terrain close to the dam deflected the flow to produce abrupt impacts with the dam. At the impact sites, instability waves were generated and increased the already large flow depths. The complex flow dynamics around the dam may produce large, local snow deposits. Furthermore, the high water content in the snow may decrease the avalanche internal friction angle, inducing wet-snow avalanches to spread further laterally than dry-snow avalanches.

    Based on our analysis, we made recommendations for designing deflecting dams and for residual risk analysis to take into account the effects of wet-snow avalanche flow.

  17. Origin and chemical composition of evaporite deposits

    Science.gov (United States)

    Moore, George William

    1960-01-01

    A comparative study of marine evaporite deposits forming at the present time along the pacific coast of central Mexico and evaporite formations of Permian age in West Texas Basin was made in order to determine if the modern sediments provide a basis for understanding environmental conditions that existed during deposition of the older deposits. The field work was supplemented by investigations of artificial evaporite minerals precipitated in the laboratory and by study of the chemical composition of halite rock of different geologic ages. The environment of deposition of contemporaneous marine salt deposits in Mexico is acidic, is strongly reducing a few centimeters below the surface, and teems with microscopic life. Deposition of salt, unlike that of many other sediments, is not wholly a constructional phenomenon. Permanent deposits result only if a favorable balance exists between deposition in the dry season and dissolution in the wet season. Evaporite formations chosen for special study in the West Texas Basin are, in ascending order, the Castile, Salado, and Rustler formations, which have a combined thickness of 1200 meters. The Castile formation is largely composed of gypsum rock, the Salado, halite rock, and the Rustler, quartz and carbonate sandstone. The lower part of the Castile formation is bituminous and contains limestone laminae. The Castile and Rustler formations thicken to the south at the expense of salt of the intervening Salado formation. The clastic rocks of the Rustler formation are interpreted as the deposits of a series of barrier islands north of which halite rock of the Salado was deposited. The salt is believed to have formed in shallow water of uniform density that was mixed by the wind. Where water depth exceeded the depth of the wind mixing, density stratification developed, and gypsum was deposited. Dense water of high salinity below the density discontinuity was overlain by less dense, more normally saline water which was derived from

  18. Manufacture of fibrous dosage forms by wet micro-patterning and drying.

    Science.gov (United States)

    Blaesi, Aron H; Saka, Nannaji

    2017-09-18

    Recently, we have introduced fibrous dosage forms prepared by the predictable deposition, or 3D-micro-patterning, of a drug-laden fibrous melt on a surface. Such dosage forms enable precisely controlled microstructures and drug release rates, and can be manufactured by an efficient, continuous melt process. However, the applicability of melt-processing to manufacture pharmaceutical dosage forms is limited because the temperatures at which suitable excipients plasticize by melting are greater than the degradation or melting temperatures of many kinds of drugs. In this work, therefore, a continuous wet micro-patterning process is presented for the manufacture of fibrous dosage forms, wherein the excipient is plasticized by solvation and solidified by drying. Models are developed to illustrate the effects of the fiber radius, the inter-fiber spacing, the drying conditions, and the viscosity of the drug-excipient-solvent mixture on microstructure, drug release properties, and process time of the dosage forms. Experimental results show that the microstructure can be well controlled by the above parameters. They also confirm that the drug release behaviour of the dosage forms is predictable. Furthermore, the small excipient particles and the thin fibers are solvated, micro-patterned, and dried rapidly, in a few seconds or about a minute, respectively, which affords short process times. Thus it is demonstrated that fibrous dosage forms with predictable properties can be readily prepared by a continuous wet micro-patterning process. Copyright © 2017. Published by Elsevier Inc.

  19. Wet Nanoindentation of the Solid Electrolyte Interphase on Thin Film Si Electrodes.

    Science.gov (United States)

    Kuznetsov, Volodymyr; Zinn, Arndt-Hendrik; Zampardi, Giorgia; Borhani-Haghighi, Sara; La Mantia, Fabio; Ludwig, Alfred; Schuhmann, Wolfgang; Ventosa, Edgar

    2015-10-28

    The solid electrolyte interphase (SEI) film formed at the surface of negative electrodes strongly affects the performance of a Li-ion battery. The mechanical properties of the SEI are of special importance for Si electrodes due to the large volumetric changes of Si upon (de)insertion of Li ions. This manuscript reports the careful determination of the Young's modulus of the SEI formed on a sputtered Si electrode using wet atomic force microscopy (AFM)-nanoindentation. Several key parameters in the determination of the Young's modulus are considered and discussed, e.g., wetness and roughness-thickness ratio of the film and the shape of a nanoindenter. The values of the Young's modulus were determined to be 0.5-10 MPa under the investigated conditions which are in the lower range of those previously reported, i.e., 1 MPa to 10 GPa, pointing out the importance of the conditions of its determination. After multiple electrochemical cycles, the polymeric deposits formed on the surface of the SEI are revealed, by force-volume mapping in liquid using colloidal probes, to extend up to 300 nm into bulk solution.

  20. Wet chemical synthesis of chitosan hydrogel-hydroxyapatite composite membranes for tissue engineering applications.

    Science.gov (United States)

    Madhumathi, K; Shalumon, K T; Rani, V V Divya; Tamura, H; Furuike, T; Selvamurugan, N; Nair, S V; Jayakumar, R

    2009-07-01

    Chitosan, a deacetylated derivative of chitin is a commonly studied biomaterial for tissue-engineering applications due to its biocompatibility, biodegradability, low toxicity, antibacterial activity, wound healing ability and haemostatic properties. However, chitosan has poor mechanical strength due to which its applications in orthopedics are limited. Hydroxyapatite (HAp) is a natural inorganic component of bone and teeth and has mechanical strength and osteoconductive property. In this work, HAp was deposited on the surface of chitosan hydrogel membranes by a wet chemical synthesis method by alternatively soaking the membranes in CaCl(2) (pH 7.4) and Na(2)HPO(4) solutions for different time intervals. These chitosan hydrogel-HAp membranes were characterized using SEM, AFM, EDS, FT-IR and XRD analyses. MTT assay was done to evaluate the biocompatibility of these membranes using MG-63 osteosarcoma cells. The biocompatibility studies suggest that chitosan hydrogel-HAp composite membranes can be useful for tissue-engineering applications.

  1. Visual wetness perception based on image color statistics.

    Science.gov (United States)

    Sawayama, Masataka; Adelson, Edward H; Nishida, Shin'ya

    2017-05-01

    Color vision provides humans and animals with the abilities to discriminate colors based on the wavelength composition of light and to determine the location and identity of objects of interest in cluttered scenes (e.g., ripe fruit among foliage). However, we argue that color vision can inform us about much more than color alone. Since a trichromatic image carries more information about the optical properties of a scene than a monochromatic image does, color can help us recognize complex material qualities. Here we show that human vision uses color statistics of an image for the perception of an ecologically important surface condition (i.e., wetness). Psychophysical experiments showed that overall enhancement of chromatic saturation, combined with a luminance tone change that increases the darkness and glossiness of the image, tended to make dry scenes look wetter. Theoretical analysis along with image analysis of real objects indicated that our image transformation, which we call the wetness enhancing transformation, is consistent with actual optical changes produced by surface wetting. Furthermore, we found that the wetness enhancing transformation operator was more effective for the images with many colors (large hue entropy) than for those with few colors (small hue entropy). The hue entropy may be used to separate surface wetness from other surface states having similar optical properties. While surface wetness and surface color might seem to be independent, there are higher order color statistics that can influence wetness judgments, in accord with the ecological statistics. The present findings indicate that the visual system uses color image statistics in an elegant way to help estimate the complex physical status of a scene.

  2. Identification of Potential Strain Heterogeneities During Wetting-Induced Compaction

    Directory of Open Access Journals (Sweden)

    Mihalache Constance

    2016-01-01

    Full Text Available Compaction upon wetting has been reported to occur in various types of unsaturated soils with damaging consequences for infrastructure in field applications. This deformation process is often referred to as “wetting-collapse”, implying that it may be unstable in nature. Recent evidences also indicate that compaction localization represents a possible mode of deformation during wetting, even in the presence of oedometric loading paths. Despite this, little work has been done from a mechanistic perspective to assess the susceptibility of these processes to localization instability. Here we assess the potential for strain localization during wetting through controllability analyses defined in light of a second-order work expression for unsaturated soils. A hydro-mechanical constitutive model with suction-dependent hardening is used to simulate classic experimental data, and the controllability criteria are specialized to capture the potential for shear band formation for a range of band inclinations under water content-controlled and suction-controlled wetting paths. The effect of changes in material characteristics was evaluated, showing that the potential for strain localization upon water-injection increases with increasing values of suction-induced hardening, and that non-associativity may have an effect on both the potential for localization under rapid wetting, as well as on the range of band angles over which it may occur. Specifically, it is possible to distinguish two well-defined stress regions, one within which strain localization is first possible with horizontal band inclinations and another in which inclined localization zones tend to be more critical. Such results provide insight on the factors that may contribute to strain localization during wetting and find general applicability in the interpretation of the response of geo-structures subjected to intense hydrologic forcing.

  3. The effect of surface water and wetting on gecko adhesion.

    Science.gov (United States)

    Stark, Alyssa Y; Sullivan, Timothy W; Niewiarowski, Peter H

    2012-09-01

    Despite profound interest in the mechanics and performance of the gecko adhesive system, relatively few studies have focused on performance under conditions that are ecologically relevant to the natural habitats of geckos. Because geckos are likely to encounter surfaces that are wet, we used shear force adhesion measurements to examine the effect of surface water and toe pad wetting on the whole-animal performance of a tropical-dwelling gecko (Gekko gecko). To test the effect of surface wetting, we measured the shear adhesive force of geckos on three substrate conditions: dry glass, glass misted with water droplets and glass fully submerged in water. We also investigated the effect of wetting on the adhesive toe pad by soaking the toe pads prior to testing. Finally, we tested for repeatability of the adhesive system in each wetting condition by measuring shear adhesion after each step a gecko made under treatment conditions. Wetted toe pads had significantly lower shear adhesive force in all treatments (0.86 ± 0.09 N) than the control (17.96 ± 3.42 N), as did full immersion in water (0.44 ± 0.03 N). Treatments with droplets of water distributed across the surface were more variable and did not differ from treatments where the surface was dry (4.72 ± 1.59 N misted glass; 9.76 ± 2.81 N dry glass), except after the gecko took multiple steps. These findings suggest that surface water and the wetting of a gecko's adhesive toe pads may have significant consequences for the ecology and behavior of geckos living in tropical environments.

  4. Modelling the system behaviour of wet snow avalanches using an expert system approach for risk management on high alpine traffic roads

    Directory of Open Access Journals (Sweden)

    A. Zischg

    2005-01-01

    Full Text Available The presented approach describes a model for a rule-based expert system calculating the temporal variability of the release of wet snow avalanches, using the assumption of avalanche triggering without the loading of new snow. The knowledge base of the model is created by using investigations on the system behaviour of wet snow avalanches in the Italian Ortles Alps, and is represented by a fuzzy logic rule-base. Input parameters of the expert system are numerical and linguistic variables, measurable meteorological and topographical factors and observable characteristics of the snow cover. Output of the inference method is the quantified release disposition for wet snow avalanches. Combining topographical parameters and the spatial interpolation of the calculated release disposition a hazard index map is dynamically generated. Furthermore, the spatial and temporal variability of damage potential on roads exposed to wet snow avalanches can be quantified, expressed by the number of persons at risk. The application of the rule base to the available data in the study area generated plausible results. The study demonstrates the potential for the application of expert systems and fuzzy logic in the field of natural hazard monitoring and risk management.

  5. Source, flux and balance of atmospheric deposition of metals at Ile-de-France; Source, flux et bilan des retombees atmospheriques de metaux en Ile de France

    Energy Technology Data Exchange (ETDEWEB)

    Azimi, S.

    2004-07-15

    The urban atmosphere is submitted to large inputs of anthropogenic contaminants arising from both stationary (power plants, industries, etc.) and mobile (road traffic) sources. These small particles may be transported over long distances and affect ecosystems. Significant dry and wet atmospheric deposition also occurs locally and contributes to the contamination of urban runoff. The aim of this study is to compare heavy metal and hydrocarbon atmospheric deposition fluxes to other input ways on agricultural and urban areas to assess their importance. Moreover, a source investigation has been done to identify the main origins of these pollutants. Before the quantification of pollutant fluxes, a comparison of several sampling procedures was performed. As a result, the sampling of total atmospheric deposition is not affected by the funnel material (Teflon and polyethylene) or by the sampling duration (7 and 28 days). However, the rinsing step of the funnel walls showed a higher relative importance during short sampling periods. The relative amount contained in these solutions reached 24 to 40 % of the total flux during weekly sampling periods and 8 to 18 % during monthly sampling periods, whatever the element considered. The temporal evolution of atmospheric deposition showed no seasonal influence on flux variations during the 2001-2002 period. Considering an 8-year period behaviour, between 1994 and 2002, a significant decrease of the deposition fluxes of Cd, Cu, Pb and Zn occurred at the Creteil site which is placed in an industrialized area of the Paris suburb. The decreasing factor reached 16, 2.5, 4 and 7.5 for these elements respectively. At the Ile-de-France scale, the deposition flux levels on urban and semi-urban areas were of the same order of magnitude (?20 tonnes per year for Ba, Cu, Pb and Sr). Since semi-urban surface area is four times higher than urban ones, the important influence of anthropogenic activities on atmospheric deposition of urban areas is

  6. A simulation study of atmospheric mercury and its deposition in the Great Lakes

    Science.gov (United States)

    Grant, Shanique L.; Kim, Myoungwoo; Lin, Peng; Crist, Kevin C.; Ghosh, Saikat; Kotamarthi, V. Rao

    2014-09-01

    The Great Lakes eco-region is one of the largest sources of fresh water in North America; however it is chronically exposed to heavy metal loadings such as mercury. In this study a comprehensive model evaluation was conducted to determine mercury loadings to the Great Lakes. The study also evaluated the relative impact of anthropogenic mercury emissions from China, regional and global sources on deposition to the Great Lakes. For the 2005 study period, CMAQ 4.7.1 model estimated a total of 6.4 ± 0.5 metric tons of mercury deposited in the Great Lakes. The total deposition breakdown showed a net loading for Lake Superior of 1906 ± 246 kg/year which is the highest of all the lakes. Lake Michigan followed with 1645 ± 203 kg/year and 1511 ± 107 kg/year in Lake Huron. The lowest total deposition was seen in Lakes Erie and Ontario amassing annual totals of 837 ± 107 kg and 506 ± 63 kg, respectively. Wet and dry deposition of mercury were both significant pathways and exhibited strong seasonal variability with higher deposition occurring in the warmer months (June-November) and the lowest in winter. Wet deposition of RGM significantly influenced the deposition proportions accounting for roughly 90% of all mercury deposited. Of the three emission sources (global background, integrated planning management (IPM) and Chinese), global background concentrations represented the maximum impact to deposition loading in the Great Lakes, except for Lake Erie and parts of Lake Michigan. There was minimal seasonality for the global background, but differences in percentage contribution between dry (28-97%) and wet deposition (43-98%) was predicted. The contributions were seen mainly in the northern sections of the Great Lakes further away from IPM point sources. These findings suggest strong localized impact of IPM sources on the southernmost lakes. Deposition as a result of emissions from China exhibited seasonality in both wet and dry deposition and showed significant

  7. A simulation study of atmospheric mercury and its deposition in the Great Lakes

    Energy Technology Data Exchange (ETDEWEB)

    Grant, Shanique L.; Kim, Myoungwoo; Lin, Peng; Crist, Kevin C.; Ghosh, Saikat; Kotamarthi, V. Rao

    2014-09-01

    The Great Lakes eco-region is one of the largest sources of fresh water in North America; however it is chronically exposed to heavy metal loadings such as mercury. In this study a comprehensive model evaluation was conducted to determine mercury loadings to the Great Lakes. The study also evaluated the relative impact of anthropogenic mercury emissions from China, regional and global sources on deposition to the Great Lakes. For the 2005 study period, CMAQ 4.7.1 model estimated a total of 6.4 ± 0.5 metric tons of mercury deposited in the Great Lakes. The total deposition breakdown showed a net loading for Lake Superior of 1906 ± 246 kg/year which is the highest of all the lakes. Lake Michigan followed with 1645 ± 203 kg/year and 1511 ± 107 kg/year in Lake Huron. The lowest total deposition was seen in Lakes Erie and Ontario amassing annual totals of 837 ± 107 kg and 506 ± 63 kg, respectively. Wet and dry deposition of mercury were both significant pathways and exhibited strong seasonal variability with higher deposition occurring in the warmer months (June–November) and the lowest in winter. Wet deposition of RGM significantly influenced the deposition proportions accounting for roughly 90% of all mercury deposited. Of the three emission sources (global background, integrated planning management (IPM) and Chinese), global background concentrations represented the maximum impact to deposition loading in the Great Lakes, except for Lake Erie and parts of Lake Michigan. There was minimal seasonality for the global background, but differences in percentage contribution between dry (28–97%) and wet deposition (43–98%) was predicted. The contributions were seen mainly in the northern sections of the Great Lakes further away from IPM point sources. These findings suggest strong localized impact of IPM sources on the southernmost lakes. Deposition as a result of emissions from China exhibited seasonality in both wet and dry deposition and showed significant

  8. Temporal compressive sensing systems

    Energy Technology Data Exchange (ETDEWEB)

    Reed, Bryan W.

    2017-12-12

    Methods and systems for temporal compressive sensing are disclosed, where within each of one or more sensor array data acquisition periods, one or more sensor array measurement datasets comprising distinct linear combinations of time slice data are acquired, and where mathematical reconstruction allows for calculation of accurate representations of the individual time slice datasets.

  9. Temporal Concurrent Constraint Programming

    DEFF Research Database (Denmark)

    Nielsen, Mogens; Palamidessi, Catuscia; Valencia, Frank Dan

    2002-01-01

    The ntcc calculus is a model of non-deterministic temporal concurrent constraint programming. In this paper we study behavioral notions for this calculus. In the underlying computational model, concurrent constraint processes are executed in discrete time intervals. The behavioral notions studied...

  10. Temporal Concurrent Constraint Programming

    DEFF Research Database (Denmark)

    Valencia, Frank Dan

    Concurrent constraint programming (ccp) is a formalism for concurrency in which agents interact with one another by telling (adding) and asking (reading) information in a shared medium. Temporal ccp extends ccp by allowing agents to be constrained by time conditions. This dissertation studies...

  11. Mesial temporal sclerosis

    African Journals Online (AJOL)

    Kurt

    2005-07-29

    Jul 29, 2005 ... Introduction. Mesial temporal sclerosis is the commonest cause of partial complex seizures. The aetiology of this condi- tion is controversial, but it is postulat- ed that both acquired and develop- mental processes may be involved. Familial cases have also been reported. Magnetic resonance imaging. (MRI) ...

  12. Temporal bone imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lemmerling, Marc [Algemeen Ziekenhuis Sint-Lucas, Gent (Belgium). Dept. of Radiology; Foer, Bert de (ed.) [Sint-Augustinus Ziekenhuis, Wilrijk (Belgium). Dept. of Radiology

    2015-04-01

    Complete overview of imaging of normal and diseased temporal bone. Straightforward structure to facilitate learning. Detailed consideration of newer imaging techniques, including the hot topic of diffusion-weighted imaging. Includes a chapter on anatomy that will be of great help to the novice interpreter of imaging findings. Excellent illustrations throughout. This book provides a complete overview of imaging of normal and diseased temporal bone. After description of indications for imaging and the cross-sectional imaging anatomy of the area, subsequent chapters address the various diseases and conditions that affect the temporal bone and are likely to be encountered regularly in clinical practice. The classic imaging methods are described and discussed in detail, and individual chapters are included on newer techniques such as functional imaging and diffusion-weighted imaging. There is also a strong focus on postoperative imaging. Throughout, imaging findings are documented with the aid of numerous informative, high-quality illustrations. Temporal Bone Imaging, with its straightforward structure based essentially on topography, will prove of immense value in daily practice.

  13. Inhibition and deactivation effects in catalytic wet oxidation of high-strength alcohol-distillery liquors

    Energy Technology Data Exchange (ETDEWEB)

    Belkacemi, K.; Larachi, F.; Hamoudi, S.; Turcotte, G.; Sayari, A. [Laval Univ., Sainte-Foy, Quebec (Canada)

    1999-06-01

    The removal efficiency of total organic carbon (TOC) from raw high-strength alcohol-distillery waste liquors was evaluated using three different treatments: thermolysis (T), noncatalytic wet oxidation (WO), and solid-catalyzed wet oxidation (CWO). The distillery liquors (TOC = 22,500 mg/l, sugars = 18,000 mg/l, and proteins = 13,500 mg/l) were produced by alcoholic fermentation of enzymatic hydrolyzates from steam-exploded timothy grass. TOC-abatement studies were conducted batchwise in a stirred autoclave to evaluate the influence of the catalyst (7:3, MnO{sub 2}/CeO{sub 2} mixed oxide), oxygen partial pressure (0.5--2.5 MPa), and temperature (453--523 K) on T, WO, and CWO processes. Although CWO outperformed T and WO, TOC conversions did not exceed {approximately}60% at the highest temperature used. Experiments provided prima facie evidence for a gradual fouling of the catalyst and a developing inhibition in the liquors which impaired deep TOC removals. Occurrence of catalyst deactivation by carbonaceous deposits was proven experimentally through quantitative and qualitative experiments such as elemental analysis and X-ray photoelectron spectroscopy. Inhibition toward further degradation of the liquors was ascribed to the occurrence of highly stable antioxidant intermediates via the Maillard reactions between dissolved sugars and proteins. A lumping kinetic model involving both reaction inhibition by dissolved intermediates and catalyst deactivation by carbonaceous deposits was proposed to account for the distribution of carbon in the liquid, solid, and the vapor phases.

  14. Episode analysis of deposition of radiocesium from the Fukushima Daiichi nuclear power plant accident.

    Science.gov (United States)

    Morino, Yu; Ohara, Toshimasa; Watanabe, Mirai; Hayashi, Seiji; Nishizawa, Masato

    2013-03-05

    Chemical transport models played key roles in understanding the atmospheric behaviors and deposition patterns of radioactive materials emitted from the Fukushima Daiichi nuclear power plant after the nuclear accident that accompanied the great Tohoku earthquake and tsunami on 11 March 2011. However, model results could not be sufficiently evaluated because of limited observational data. We assess the model performance to simulate the deposition patterns of radiocesium ((137)Cs) by making use of airborne monitoring survey data for the first time. We conducted ten sensitivity simulations to evaluate the atmospheric model uncertainties associated with key model settings including emission data and wet deposition modules. We found that simulation using emissions estimated with a regional-scale (∼ 500 km) model better reproduced the observed (137)Cs deposition pattern in eastern Japan than simulation using emissions estimated with local-scale (∼ 50 km) or global-scale models. In addition, simulation using a process-based wet deposition module reproduced the observations well, whereas simulation using scavenging coefficients showed large uncertainties associated with empirical parameters. The best-available simulation reproduced the observed (137)Cs deposition rates in high-deposition areas (≥ 10 kBq m(-2)) within 1 order of magnitude and showed that deposition of radiocesium over land occurred predominantly during 15-16, 20-23, and 30-31 March 2011.

  15. Climate-change signals in national atmospheric deposition program precipitation data

    Science.gov (United States)

    Wetherbee, Gregory A.; Mast, M. Alisa

    2016-01-01

    National Atmospheric Deposition Program (NADP)/National Trends Network precipitation type, snow-season duration, and annual timing of selected chemical wet-deposition maxima vary with latitude and longitude within a 35-year (1979–2013) data record for the contiguous United States and Alaska. From the NADP data collected within the region bounded by 35.6645°–48.782° north latitude and 124°–68° west longitude, similarities in latitudinal and longitudinal patterns of changing snow-season duration, fraction of annual precipitation recorded as snow, and the timing of chemical wet-deposition maxima, suggest that the chemical climate of the atmosphere is linked to physical changes in climate. Total annual precipitation depth has increased 4–6 % while snow season duration has decreased from approximately 7 to 21 days across most of the USA, except in higher elevation regions where it has increased by as much as 21 days. Snow-season precipitation is increasingly comprised of snow, but annually total precipitation is increasingly comprised of liquid precipitation. Meanwhile, maximum ammonium deposition occurs as much as 27 days earlier, and the maximum nitrate: sulfate concentration ratio in wet-deposition occurs approximately 10–21 days earlier in the year. The maximum crustal (calcium + magnesium + potassium) cation deposition occurs 2–35 days earlier in the year. The data suggest that these shifts in the timing of atmospheric wet deposition are linked to a warming climate, but the ecological consequences are uncertain.

  16. Communication, Technology, Temporality

    Directory of Open Access Journals (Sweden)

    Mark A. Martinez

    2012-08-01

    Full Text Available This paper proposes a media studies that foregrounds technological objects as communicative and historical agents. Specifically, I take the digital computer as a powerful catalyst of crises in communication theories and certain key features of modernity. Finally, the computer is the motor of “New Media” which is at once a set of technologies, a historical epoch, and a field of knowledge. As such the computer shapes “the new” and “the future” as History pushes its origins further in the past and its convergent quality pushes its future as a predominate medium. As treatment of information and interface suggest, communication theories observe computers, and technologies generally, for the mediated languages they either afford or foreclose to us. My project describes the figures information and interface for the different ways they can be thought of as aspects of communication. I treat information not as semantic meaning, formal or discursive language, but rather as a physical organism. Similarly an interface is not a relationship between a screen and a human visual intelligence, but is instead a reciprocal, affective and physical process of contact. I illustrate that historically there have been conceptions of information and interface complimentary to mine, fleeting as they have been in the face of a dominant temporality of mediation. I begin with a theoretically informed approach to media history, and extend it to a new theory of communication. In doing so I discuss a model of time common to popular, scientific, and critical conceptions of media technologies especially in theories of computer technology. This is a predominate model with particular rules of temporal change and causality for thinking about mediation, and limits the conditions of possibility for knowledge production about communication. I suggest a new model of time as integral to any event of observation and analysis, and that human mediation does not exhaust the

  17. Deposition and Resuspension Section

    Energy Technology Data Exchange (ETDEWEB)

    Slinn, W. G.N.; Horst, T. W.; Sehmel, G. A.; Hodgson, W. H.; Lloyd, F. D.; Orgill, M. M.; Bander, T. J.; Thorp, J. M.; Schwendiman, L. C.; Young, J. A.; Tanner, T. M.; Thomas, C. W.; Wogman, N. A.; Petersen, M. R.; Hadlock, R. K.; Droppo, J. G.; Woodruff, R. K.

    1976-03-01

    Nineteen papers are covered in this section. Significant contributions were made in 1975 in both the theoretical and the more practical experimental measurements of particle deposition and resuspension. Solutions of theoretical deposition-resuspension equations were formulated and nondimensionalized air and ground concentrations were predicted as a function of distance. In other theoretical studies assumptions and analyses regarding surface boundary conditions were investigated and methods presented whereby they can be fitted together within a single theoretical framework. Deposition in vegetation canopies was considered; formulations were developed and conclusions drawn regarding canopy filtration efficiency. Dry deposition of gases was shown to be rate-limited by many processes, and experiments and equipment were designed to measure gradients of SO/sub 2/ and deposition fluxes. A computer model was improved and used to predict downwind concentrations for a generalized area source. A dimensional analysis correlation was formulated from experimental particle deposition velocity data, but was found to show insignificant improvement when compared statistically with an earlier derived correlation. Wind tunnel measurements of deposition velocities to gravel beds and scaled trees showed that particles will penetrate very significantly to underlying surfaces. Initial field experiments measured deposition velocity to sagebrush canopies. Other controlled field studies were initiated for measuring resuspension, including resuspension from truck traffic. Suspension of soil and the size distribution of particles airborne under various air regimes were studied. In the large METROMEX study done near St. Louis, several pollutants were sampled and analyzed as a function of distance. These studies gave insight into the relative inportance of dry deposition and atmospheric dispersion as mechanisms for reducing air concentrations. (auth)

  18. Improved hydrogen sorption kinetics in wet ball milled Mg hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Li

    2011-05-04

    In this work, wet ball milling method is used in order to improve hydrogen sorption behaviour due to its improved microstructure of solid hydrogen materials. Compared to traditional ball milling method, wet ball milling has benefits on improvement of MgH{sub 2} microstructure and further influences on its hydrogen sorption behavior. With the help of solvent tetrahydrofuran (THF), wet ball milled MgH{sub 2} powder has much smaller particle size and its specific surface area is 7 times as large as that of dry ball milled MgH{sub 2} powder. Although after ball milling the grain size is decreased a lot compared to as-received MgH{sub 2} powder, the grain size of wet ball milled MgH{sub 2} powder is larger than that of dry ball milled MgH{sub 2} powder due to the lubricant effect of solvent THF during wet ball milling. The improved particle size and specific surface area of wet ball milled MgH{sub 2} powder is found to be determining its hydrogen sorption kinetics especially at relatively low temperatures. And it also shows good cycling sorption behavior, which decides on its industrial applicability. With three different catalysts MgH{sub 2} powder shows improved hydrogen sorption behavior as well as the cyclic sorption behavior. Among them, the Nb{sub 2}O{sub 5} catalyst is found to be the most effective one in this work. Compared to the wet ball milled MgH{sub 2} powder, the particle size and specific surface area of the MgH{sub 2} powder with catalysts are similar to the previous ones, while the grain size of the MgH{sub 2} with catalysts is much finer. In this case, two reasons for hydrogen sorption improvement are suggested: one is the reduction of the grain size. The other may be as pointed out in some literatures that formation of new oxidation could enhance the hydrogen sorption kinetics, which is also the reason why its hydrogen capacity is decreased compared to without catalysts. After further ball milling, the specific surface area of wet ball milled Mg

  19. Electroless atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, David Bruce; Cappillino, Patrick J.; Sheridan, Leah B.; Stickney, John L.; Benson, David M.

    2017-10-31

    A method of electroless atomic layer deposition is described. The method electrolessly generates a layer of sacrificial material on a surface of a first material. The method adds doses of a solution of a second material to the substrate. The method performs a galvanic exchange reaction to oxidize away the layer of the sacrificial material and deposit a layer of the second material on the surface of the first material. The method can be repeated for a plurality of iterations in order to deposit a desired thickness of the second material on the surface of the first material.

  20. Aroma recovery from roasted coffee by wet grinding.

    Science.gov (United States)

    Baggenstoss, J; Thomann, D; Perren, R; Escher, F

    2010-01-01

    Aroma recovery as determined by solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) was compared in coffees resulting from conventional grinding processes, and from wet grinding with cold and hot water. Freshly roasted coffee as well as old, completely degassed coffee was ground in order to estimate the relationship of internal carbon dioxide pressure in freshly roasted coffee with the aroma loss during grinding. The release of volatile aroma substances during grinding was found to be related to the internal carbon dioxide pressure, and wet grinding with cold water was shown to minimize losses of aroma compounds by trapping them in water. Due to the high solubility of roasted coffee in water, the use of wet-grinding equipment is limited to processes where grinding is followed by an extraction step. Combining grinding and extraction by the use of hot water for wet grinding resulted in considerable losses of aroma compounds because of the prolonged heat impact. Therefore, a more promising two-step process involving cold wet grinding and subsequent hot extraction in a closed system was introduced. The yield of aroma compounds in the resulting coffee was substantially higher compared to conventionally ground coffee. © 2010 Institute of Food Technologists®

  1. Physicochemical properties and combustion behavior of duckweed during wet torrefaction.

    Science.gov (United States)

    Zhang, Shuping; Chen, Tao; Li, Wan; Dong, Qing; Xiong, Yuanquan

    2016-10-01

    Wet torrefaction of duckweed was carried out in the temperature range of 130-250°C to evaluate the effects on physicochemical properties and combustion behavior. The physicochemical properties of duckweed samples were investigated by ultimate analysis, proximate analysis, FTIR, XRD and SEM techniques. It was found that wet torrefaction improved the fuel characteristics of duckweed samples resulting from the increase in fixed carbon content, HHVs and the decrease in nitrogen and sulfur content and atomic ratios of O/C and H/C. It can be seen from the results of FTIR, XRD and SEM analyses that the dehydration, decarboxylation, solid-solid conversion, and condensation polymerization reactions were underwent during wet torrefaction. In addition, the results of thermogravimetric analysis (TGA) in air indicated that wet torrefaction resulted in significant changes on combustion behavior and combustion kinetics parameters. Duckweed samples after wet torrefaction behaved more char-like and gave better combustion characteristics than raw sample. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Experimental and Theoretical Investigations of Wet Flue Gas Desulphurisation

    DEFF Research Database (Denmark)

    Kiil, Søren

    This thesis describes experimental and theoretical investigations of wet flue gas desulphurisa-tion (FGD). A review of the current knowledge of the various rate determining steps in wet FGD plants is presented. The experimental work covers laboratory studies as well as pilot- and full-scale exper......This thesis describes experimental and theoretical investigations of wet flue gas desulphurisa-tion (FGD). A review of the current knowledge of the various rate determining steps in wet FGD plants is presented. The experimental work covers laboratory studies as well as pilot- and full...... degree of desulphuri-sation and absorber pH profile for the two limestone types using a holding tank pH of 5.5, but the residual limestone in the gypsum was significantly lower for the chalk. Furthermore, simulations showed that between 10 and 30 % of the limestone dissolves in the absorber de......-pending on the process conditions. A typical holding tank pH of 5-5.5 (also used in full-scale wet FGD packed towers) was found to be a reasonable compromise between residual lime-stone in the gypsum and the degree of desulphurisation. Simulations were only slightly sensi-tive to the temperature in the interval 313...

  3. Dust deposition: the best way to constrain the simulated dust mass budget?

    Science.gov (United States)

    Bergametti, Gilles

    2010-05-01

    Dust deposition is a key process of the dust cycle. In term of mass, deposition is equal to emissions and dust deposition being a size dependent process, the evolution of the size distribution during transport is in a large part controlled by the intensity of the deposition pathways. Moreover, the dust material removed from the atmosphere is a key component of many biogeochemical cycles: far from the source regions, atmospheric dust deposition supplies surface seawater with soil-derived elements, many of them (Fe, P. . .) being suspected to be limiting nutrients for oceanic ecosystems while in the continental areas, deposition contributes to soil formation in many surrounding desert areas. Finally, dust archives from deep ocean sediments, ice cores, lakes or continental loess deposits are used as proxies of past environmental and climate conditions. Thus, dust deposition is of high environmental interest and a special attention should be given to properly assess its intensity and spatio-temporal fields. Despite the major role and the various impacts of dust deposition, little attention was given to both deposition measurements and modelling. However, a better knowledge of the spatial and temporal distribution of the deposition field would greatly help to better constrain the dust cycle. Indeed, even if recent progresses have been made in dust emission modelling, it could remain large uncertainties on the intensity of the simulated dust emissions. Having a good estimate of the deposition will contribute to better assess the relevance of simulated dust emissions.

  4. Modeling investigation of light-absorbing aerosols in the Amazon Basin during the wet season

    Directory of Open Access Journals (Sweden)

    Q. Wang

    2016-11-01

    Full Text Available We use a global chemical transport model (GEOS-Chem to interpret observed light-absorbing aerosols in Amazonia during the wet season. Observed aerosol properties, including black carbon (BC concentration and light absorption, at the Amazon Tall Tower Observatory (ATTO site in the central Amazon have relatively low background levels but frequently show high peaks during the study period of January–April 2014. With daily temporal resolution for open fire emissions and modified aerosol optical properties, our model successfully captures the observed variation in fine/coarse aerosol and BC concentrations as well as aerosol light absorption and its wavelength dependence over the Amazon Basin. The source attribution in the model indicates the important influence of open fire on the observed variances of aerosol concentrations and absorption, mainly from regional sources (northern South America and from northern Africa. The contribution of open fires from these two regions is comparable, with the latter becoming more important in the late wet season. The analysis of correlation and enhancement ratios of BC versus CO suggests transport times of < 3 days for regional fires and  ∼  11 days for African plumes arriving at ATTO during the wet season. The model performance of long-range transport of African plumes is also evaluated with observations from AERONET, MODIS, and CALIOP. Simulated absorption aerosol optical depth (AAOD averaged over the wet season is lower than 0.0015 over the central Amazon, including the ATTO site. We find that more than 50 % of total absorption at 550 nm is from BC, except for the northeastern Amazon and the Guianas, where the influence of dust becomes significant (up to 35 %. The brown carbon contribution is generally between 20 and 30 %. The distribution of absorption Ångström exponents (AAE suggests more influence from fossil fuel combustion in the southern part of the basin (AAE  ∼  1 but more

  5. Fog collection and deposition modelling - EcoCatch Lunz

    Science.gov (United States)

    Koller, M. W.; Ramírez-Santa Cruz, C.; Leder, K.; Bauer, H.; Dorninger, M.; Hofhansl, F.; Wanek, W.; Kasper-Giebl, A.

    2010-07-01

    The area of Lunz am See (N 047.855°, E 015.068°, 650 m a.s.l.) in Lower Austria has been subject to long term monitoring of meteorological parameters as well as wet deposition. Even though Lunz is known for its good air quality, with about 200 days of precipitation per year reaching an annual average of 1500 mm deposition, immission fluxes reach levels of critical loads. For instance, nitrogen input from wet deposition of nitrate and ammonium is > 14 kg ha-1 a-1, and sulphur input from sulphate is 5 kg ha-1 a-1. In the framework of the EcoCatch project1) wet, dry and occult deposition have been investigated in detail in an alluvial forest near the Biological Station (Lunz/See) since September 2008. The overall contribution of dry and occult deposition was expected to be comparably low and only of importance in times of decreased wet deposition. Collection of fog samples was performed with an active fog sampler, regulated by a Vaisala PWD-12 sensor monitoring visibility. Temperature, relative humidity, wind speed and direction were logged by a HOBO weather station. Filter stacks were used for sampling of aerosol particles and gaseous components and a Wet And Dry Only Sampler (WADOS) was used to sample precipitation. Solute analysis was carried out via ion chromatography. Alkali and earth alkali metals, chloride as well as ammonium, sulphate and nitrate were quantified in rain, aerosol and fog samples on an event basis. In addition dry deposition included nitrogen oxide and dioxide, sulphur dioxide and ammonia measurements. A site specific relation of liquid water content (LWC) to visibility was established using the collection rate and the known collection efficiency of the fog sampler. A modified version of the fog deposition resistance model devised by G.M. Lovett was used to quantify occult deposition onto the alluvial forest. The surface area index of local vegetation was measured with a SunScan System and tree height was determined using a Vertex IV

  6. Can I Stop Myself From Having a Wet Dream? (For Teens)

    Science.gov (United States)

    ... Can I Stop Myself From Having a Wet Dream? KidsHealth > For Teens > Can I Stop Myself From Having a Wet Dream? Print A A A Can I stop myself from having a wet dream? – Tom* You really can't stop wet dreams, ...

  7. Alluvial Deposits in Iowa

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — This coverage maps alluvial deposits throughout Iowa. This generally would include areas of alluvial soils associated with modern streams that are identified on...

  8. Speleothem (Cave Deposit) Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Records of past temperature, precipitation, and other aspects of climate derived from mineral deposits found in caves. Parameter keywords describe what was measured...

  9. Automatic Payroll Deposit System.

    Science.gov (United States)

    Davidson, D. B.

    1979-01-01

    The Automatic Payroll Deposit System in Yakima, Washington's Public School District No. 7, directly transmits each employee's salary amount for each pay period to a bank or other financial institution. (Author/MLF)

  10. Podiform chromite deposits

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Location and characteristics of 1,124 individual mineral deposits of this type, with grade and tonnage models for chromium as well as several related elements.

  11. Modeling of GPS tropospheric delay wet Neill mapping function (NMF)

    Science.gov (United States)

    Sakidin, Hamzah; Ahmad, Asmala; Bugis, Ismadi

    2014-10-01

    The modeling of the GPS tropospheric delay mapping function should be revised by modifying or simplify its mathematical model. Some current mapping functions models are separated into hydrostatic and the wet part. The current tropospheric delay models use mapping functions in the form of continued fractions. This model is quite complex and need to be simplified. By using regression method, the wet mapping function models has been selected to be simplified. There are eleven operations for wet mapping function component of Neill Mapping Function (NMF), to be carried out before getting the mapping function scale factor. So, there is a need to simplify the mapping function models to allow faster calculation and also better understanding of the models.

  12. Drying and wetting of building materials and components

    CERN Document Server

    2014-01-01

    This book, Drying and Wetting of Building Materials and Components, provides a collection of recent contributions in the field of drying and wetting in porous building materials. The main benefit of the book is that it discusses some of the most important topics related to the drying and wetting processes, namely, innovations and trends in drying science and technology, drying mechanism and theory, equipment, advanced modelling, complex simulation and experimentation. At the same time, these topics will be going to the encounter of a variety of scientific and engineering disciplines. The book is divided in several chapters that intend to be a resume of the current state of knowledge for benefit of professional colleagues.

  13. Development of the Internet Watershed Educational Tool (InterWET

    Directory of Open Access Journals (Sweden)

    Shane Parson

    2000-01-01

    Full Text Available Watershed educational and informational efforts have largely neglected to inform one important group of decision-makers: local government officials. The Internet Watershed Educational Tool (InterWET was developed to help inform local officials about water resources, using as a case study the Spring Creek Watershed in central Pennsylvania. Utilizing the "microworlds" concept, InterWET consists of a set of web pages that present water resource issues and components from different perspectives. Specifically, the components of surface runoff, groundwater flow, detached and delivered sediment, in-stream nutrients, and fish populations are presented from the perspectives of a researcher, a conservationist, and a local official. In addition to informing local officials, InterWET can also be used as a stand-alone informational resource or as part of larger watershed educational efforts.

  14. In situ transesterification of highly wet microalgae using hydrochloric acid.

    Science.gov (United States)

    Kim, Bora; Im, Hanjin; Lee, Jae W

    2015-06-01

    This study addresses in situ transesterification of highly wet microalgae with hydrochloric acid (HCl) as a catalyst. In situ transesterification was performed by heating the mixture of wet algal cells, HCl, methanol, and solvent in one pot, resulting in the fatty acid methyl ester (FAME) yield over 90% at 95°C. The effects of reaction variables of temperature, amounts of catalyst, reactant, and solvent, and type of solvents on the yield were investigated. Compared with the catalytic effect of H2SO4, in situ transesterification using HCl has benefits of being less affected by moisture levels that are as high as or above 80%, and requiring less amounts of catalyst and solvent. For an equimolar amount of catalyst, HCl showed 15wt.% higher FAME yield than H2SO4. This in situ transesterification using HCl as a catalyst would help to realize a feasible way to produce biodiesel from wet microalgae. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Wetting and Spreading of Molten Volcanic Ash in Jet Engines.

    Science.gov (United States)

    Song, Wenjia; Lavallée, Yan; Wadsworth, Fabian B; Hess, Kai-Uwe; Dingwell, Donald B

    2017-04-20

    A major hazard to jet engines posed by volcanic ash is linked to the wetting and spreading of molten ash droplets on engine component surfaces. Here, using the sessile drop method, we study the evolution of the wettability and spreading of volcanic ash. We employ rapid temperature changes up to 1040-1450 °C, to replicate the heating conditions experienced by volcanic ash entering an operating jet engine. In this scenario, samples densify as particles coalesce under surface tension until they form a large system-sized droplet (containing remnant gas bubbles and crystals), which subsequently spreads on the surface. The data exhibit a transition from a heterogeneous to a homogeneous wetting regime above 1315 °C as crystals in the drops are dissolved in the melt. We infer that both viscosity and microstructural evolution are key controls on the attainment of equilibrium in the wetting of molten volcanic ash droplets.

  16. Some specificities of wetting by cyanobiphenyl liquid crystals

    Energy Technology Data Exchange (ETDEWEB)

    Delabre, U; Richard, C; Cazabat, A M, E-mail: cazabat@lps.ens.f [Laboratoire de Physique Statistique, Ecole Normale Superieure, Universite Pierre et Marie Curie, CNRS, 24 rue Lhomond, 75231 Paris Cedex 05 (France)

    2009-11-18

    The present paper provides an up to date restatement of the wetting behaviour of the series of cyanobiphenyl liquid crystals (LCs) on usual substrates, i.e. oxidized silicon wafers, water and glycerol, at both the macroscopic and microscopic scale, in the nematic range of temperature. We show that on water the systems are close to a wetting transition, especially 5CB and 7CB. In that case, the wetting behaviour is controlled by the presence of impurities. On a mesoscopic scale, we observe for all our (thin LC film-substrate) systems an identical, complex, but well defined general scenario, not accounted for by the available models. In the last part, we present a study on line tension which results from the specific organization of LCs at the edge of the nematic film. We report preliminary results on two-dimensional film coalescence where this line tension plays a major role.

  17. Liquid Metal Phagocytosis: Intermetallic Wetting Induced Particle Internalization.

    Science.gov (United States)

    Tang, Jianbo; Zhao, Xi; Li, Jing; Zhou, Yuan; Liu, Jing

    2017-05-01

    A biomimetic cellular-eating phenomenon in gallium-based liquid metal to realize particle internalization in full-pH-range solutions is reported. The effect, which is called liquid metal phagocytosis, represents a wet-processing strategy to prepare various metallic liquid metal-particle mixtures through introducing excitations such as an electrical polarization, a dissolving medium, or a sacrificial metal. A nonwetting-to-wetting transition resulting from surface transition and the reactive nature of the intermetallic wetting between the two metallic phases are found to be primarily responsible for such particle-eating behavior. Theoretical study brings forward a physical picture to the problem, together with a generalized interpretation. The model developed here, which uses the macroscopic contact angle between the two metallic phases as a criterion to predict the particle internalization behavior, shows good consistency with experimental results.

  18. Helminths in rodents from Wet Markets in Thailand

    Directory of Open Access Journals (Sweden)

    Ribas A.

    2016-12-01

    Full Text Available Only a few surveys have ever been carried out of the helminths of the commensal rodents found in the traditional wet markets that play such an important part of daily life in South-east Asia. The potential of rodents as reservoirs of zoonoses including helminths is of great interest since in these markets humans and rodents come into closer contact than in other environments and food may be indirectly contaminated via rodent faeces. Helminths in a total of 98 rats belonging to two species (Rattus norvegicus and Rattus exulans were surveyed in eight traditional wet markets in Udon Thani, Thailand. Thirteen species of helminths were recovered, seven of which are potentially zoo-notic, with an overall prevalence of 89.8 %. Our results show that rodents in wet markets could pose a threat to human health as potential reservoirs of zoonotic helminthiases.

  19. Tailoring the microstructure of particle-stabilized wet foams.

    Science.gov (United States)

    Gonzenbach, Urs T; Studart, André R; Tervoort, Elena; Gauckler, Ludwig J

    2007-01-30

    Inorganic colloidal particles which are in situ hydrophobized upon adsorption of short-chain amphiphilic molecules can be used as foam stabilizers. In this study, we tailor the microstructure of particle-stabilized wet foams, namely, the foam air content, average bubble size, and bubble size distribution, by changing the composition of the initial colloidal suspension. Wet foams featuring average bubble sizes between 10 and 200 microm and air contents between 45% and 90% were obtained by adjusting the amphiphile and particle concentration, pH, ionic strength, and particle size in the initial suspension. The influence of these parameters on the bubble size was satisfactorily described in terms of a balance between the shear stress applied during mixing and the counteracting Laplace pressure of the air bubbles. This model, originally developed for oil droplets in emulsions, can therefore be used to deliberately tailor the microstructure of particle-stabilized wet foams.

  20. Psychiatric disturbance, urgency, and bacteriuria in children with day and night wetting.

    Science.gov (United States)

    Berg, I; Fielding, D; Meadow, R

    1977-01-01

    Forty children with day and night wetting were compared with 46 with night wetting only to see if day wetting was then associated with particular clinical features. Interviews with mothers, questionnaries completed by teachers, physical investigations, and measurement of functional bladder capacities were used. Day wetting combined with bed wetting occurred equally in boys and girls and was associated with daytime urgency and greater frequency of psychiatric disturbance. In boys, soiling was also associated. In girls, bacteriuria, which appeared to be caused by the day wetting, occurred in about 50%. Neither daytime frequency nor small functional bladder capacity were specifically related to day wetting. PMID:921313