WorldWideScience

Sample records for dry deposition

  1. DRY DEPOSITION OF POLLUTANTS TO FORESTS

    Science.gov (United States)

    We report on the results of an extensive field campaign to measure dry deposition of ozone and sulfur dioxide to a sample of forest types in the United States. Measurements were made for full growing seasons over a deciduous forest in Pennsylvania and a mixed deciduous-conifer...

  2. On the dry deposition of submicron particles

    Energy Technology Data Exchange (ETDEWEB)

    Wesely, M. L.

    1999-10-08

    The air-surface exchange of particles can have a strong role in determining the amount, size, and chemical composition of particles in the troposphere. Here the authors consider only dry processes (deposition processes not directly aided by precipitation) and mostly address particles less than about 2 {micro}m in diameter (often referred to as submicron particles because most of such particles are less than 1 {micro}m in diameter). The processes that control the dry exchange of particulate material between the atmosphere and the surface of the Earth are numerous, highly varied, and sometimes poorly understood. As a result, determining which of the surface processes to parameterize or simulate in modeling the tropospheric mass budget of a particulate substance can be a significant challenge. Dry deposition, for example, can be controlled by a combination of Brownian diffusion, impaction, interception, and gravitational settling, depending on the size of the particles, the roughness of the surface on both micrometeorological and microscopic scales, the geometrical structure of vegetative canopies, and other surface characteristics such as wetness. Particles can be added to the lower atmosphere by resuspension from land surfaces and sea spray. The roles of rapid gas-to-particle conversion and growth or shrinkage of particles as a result of water condensation or evaporation in the lower few meters of the atmosphere can also have a significant impact on particle concentrations in the lower atmosphere. Here, a few micrometeorological observations and inferences on particle air-surface exchange are briefly addressed.

  3. Dry deposition of sulfur to forests in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Akira; Sato, Kazuo; Fujita, Shin-ichi [Central Research Institute of Electric Power Industry, Tokyo (Japan)

    1996-12-31

    Dry deposition is an important input process of acidifying compounds to forest ecosystem. However, dry deposition to forest was largely unstudied in Japan, despite the fact that about 70% of the land is covered with forest. To assess the contribution of dry deposition to the total (wet + dry) input of sulfur to forest, we estimated dry deposition velocities and fluxes of sulfur to three different forest stands (cedar [Cryptomeria japonica], pine [Pinus densiflora], and oak [Quercus serrata]) located at Mt. Akagi in Gumma Prefecture, Japan. Micro meteorology above canopies, atmospheric concentrations, and throughfall fluxes were measured from October 1994 to September 1995. Deposition velocities of sulfur dioxide and particulate sulfate were determined by using the inferential method, based on the result of meteorological measurements. Dry deposition fluxes were calculated from the estimated deposition velocities and the result of concentration measurements. Dry deposition fluxes of sulfate for cedar, pine, and oak were estimated at 164 eq/ha/y, 143 eq/ha/y, and 131 eq/ha/y, respectively. The relative contribution of dry deposition ranged from 20% to 22% of the total sulfur deposition. However, these results might be underestimated because estimated fluxes were about 30% lower than observed net throughfall fluxes ([throughfall + stemflow] - precipitation) in cedar and pine forest stands.

  4. Simulated dry deposition of nitric acid near forest edges

    NARCIS (Netherlands)

    DeJong, JJM; Klaassen, W; Jong, J.J.M. de

    1997-01-01

    Dry deposition is simulated to understand and generalize observations of enhanced deposition of air pollution near forest edges. Nitric acid is taken as an example as its deposition velocity is often assumed to be determined by turbulent transport only. The simulations are based on the micro-meteoro

  5. Sulfate dry deposition to red oak and tulip poplar leaves

    Energy Technology Data Exchange (ETDEWEB)

    Vandenberg, J.J. (US Environmental Protection Agency Research Triangle Park, NC (USA)); Knoerr, K.R. (Duke Univ Durham, NC (USA))

    1988-01-01

    Measurement of rates of atmospheric sulfate dry deposition to vegetation is necessary to assess biophysical relationships. However, micrometeorological measurement techniques have stringent site and equipment requirements and direct estimation techniques have procedural and contamination difficulties. This paper describes the development and testing of a leaf washing technique to directly measure the rate of sulfate dry deposition to hardwood forest vegetation. The leaf washing technique was developed by comparing the rate of removal of sulfur dry deposited to leaf surfaces with the rate and extent of leaching from the internal sulfur pool.

  6. MEASUREMENT AND MODELING OF THE DRY DEPOSITION OF PEROXIDES

    Science.gov (United States)

    Measurements of the dry deposition velocity (Vd) of hydrogen peroxide (H2O2) and total organic peroxides (ROOH) were made during four experiments at three forested sites. Details and uncertainties associated with the measurement of peroxide...

  7. Dry deposition modelling of air pollutants over urban areas

    Science.gov (United States)

    Cherin, N.; Roustan, Y.; Seigneur, C.; Musson Genon, L.

    2012-04-01

    More than one-half of the world's inhabitants lives in urban areas. Consequently, the evolution of pollutants inside these urban areas are problems of great concern in air quality studies. Though the dry deposition fluxes of air pollutants, which are known to be significant in the neighborhood of sources of pollution, like urban areas, have not been modeled precisely until recently within urban areas. By reviewing the physics of the processes leading to the dry deposition of air pollutants, it is clear that atmosphere turbulence is crucial for dry deposition. Urban areas, and particularly buildings, are known to significantly impact flow fields and then by extension the dry deposition fluxes. Numerous urban schemes have been developed in the past decades to approximate the effect of the local scale urban elements on drag, heat flux and radiative budget. The most recent urban canopy models are based on quite simple geometries, but sufficiently close to represent the aerodynamic and thermal characteristics of cities. These canopy models are generally intended to parameterize aerodynamic and thermal fields, but not dry deposition. For dry deposition, the current classical "roughness" approach, uses only two representative parameters, z0 and d, namely the roughness length and the zero-plane displacement height to represent urban areas. In this work, an innovative dry deposition model based on the urban canyon concept, is proposed. It considers a single road, bordered by two facing buildings, which are treated separately. It accounts for sub-grid effects of cities, especially a better parameterization of the turbulence scheme, through the use of local mixing length and a more detailled description of the urban area and key parameters within the urban canopy. Three different flow regimes are distinguished in the urban canyon according to the height-to-width ratio: isolated roughness flow, wake interference flow and skimming flow regime. The magnitude of differences in

  8. Dry Deposition from Sahara Sources Regions of Western Africa

    Directory of Open Access Journals (Sweden)

    B. Douaiba

    2014-01-01

    Full Text Available Sahara dust storms during March 2004 have attracted much attention from the dust-research community due to their intensity, wide coverage, and endurance. In the present work, the dry deposition mechanisms of mineral dust are analysed during an event on the 3 March 2004 over the Northwest African coast. This particular case was chosen based on the strong dry removal that occurred, rendering it ideal for examining the deposition processes. The simulation of synoptic conditions and dry deposition of four dust particles including clay, small silt, large silt, and sand was performed with Eta model, coupled with a desert dust cycle module. The results have been compared with surface data from weather stations in North Africa, data of dry metals from stations located in Gran Canaria, and various satellite images such as European Organization for the Exploitation of Meteorological Satellites and Moderate Resolution Imaging Spectroradiometer for the period in question.

  9. Effects of the climate change on regional ozone dry deposition

    OpenAIRE

    Kolozsi-Komjáthy, E.; Mészáros, R.; Lagzi, I.

    2011-01-01

    This impact study investigates connections between the regional climate change and the tropospheric ozone deposition over different vegetations in Hungary due to the possible changes of atmospheric and environmental properties. The spatial and temporal variability of the dry deposition velocity of ozone was estimated for different time periods (1961–1990 for reference period and two future scenarios: 2021–2050 and 2071–2100). Simulations were performed with...

  10. Organic sedimentary deposits in Titan's dry lakebeds: Probable evaporite

    Science.gov (United States)

    Barnes, J.W.; Bow, J.; Schwartz, J.; Brown, R.H.; Soderblom, J.M.; Hayes, A.G.; Vixie, G.; Le, Mouelic S.; Rodriguez, S.; Sotin, C.; Jaumann, R.; Stephan, K.; Soderblom, L.A.; Clark, R.N.; Buratti, B.J.; Baines, K.H.; Nicholson, P.D.

    2011-01-01

    We report the discovery of organic sedimentary deposits at the bottom of dry lakebeds near Titan's north pole in observations from the Cassini Visual and Infrared Mapping Spectrometer (VIMS). We show evidence that the deposits are evaporitic, making Titan just the third known planetary body with evaporitic processes after Earth and Mars, and is the first that uses a solvent other than water. ?? 2011 Elsevier Inc.

  11. Litterfall mercury dry deposition in the eastern USA

    Science.gov (United States)

    Martin R. Risch; John F. DeWild; David P. Krabbenhoft; Randall K. Kolka; Leiming. Zhang

    2012-01-01

    Mercury (Hg) in autumn litterfall frompredominately deciduous forestswas measured in 3 years of samples from 23 Mercury Deposition Network sites in 15 states across the eastern USA. Annual litterfall Hg dry depositionwas significantly higher (median 12.3 micrograms per square meter (µg/m2), range 3.5-23.4 µg/m2...

  12. Aerosol dry deposition on canopies of plane obstacles

    Science.gov (United States)

    Petroff, A.; Zhang, L.

    2007-12-01

    A new model to describe aerosol transport and dry deposition on vegetative canopies has been proposed recently by Petroff et al. and applied to canopies of cylindrical obstacles such as coniferous forest (Petroff et al., 2007, Aerosol dry deposition on vegetative canopies. Part II: A new modeling approach and applications, submitted to Atmospheric Environment). In the present study, the approach is extended to canopies of plane obstacles such as grass, crop or broadleaf forest. The model takes into account the characteristics of the canopy, the aerosol and the aerodynamics. Deposition terms are modeled following an up-scaling procedure, which is based on the knowledge of collection dynamics on each individual obstacle and on the statistical distribution of these collecting elements. The statistical description applies to geometrical properties such as leaf characteristic length and orientation. Deposition mechanisms considered in this model include Brownian diffusion, interception, inertial impaction, turbulent impaction and gravitational settling. For interception, no adequate parameterisation is available in the literature to describe the collection on individual obstacle. Thus, an original parameterisation is derived for plane obstacle and is based on potential flow theory. Aerosol transport is described in a mono-dimensional configuration and neutral stratification of the atmosphere is assumed. Preliminary results indicate that the present model agrees with existing measurements data obtained both in wind-tunnel and on site.

  13. Dry deposition of large, airborne particles onto a surrogate surface

    Science.gov (United States)

    Kim, Eugene; Kalman, David; Larson, Timothy

    Simultaneous measurements of particle dry deposition flux and airborne number concentration in the open atmosphere were made using three different types of artificially generated particles in the size range 10-100 μm - perlite, diatomaceous earth and glass beads. A combination of gravimetric analysis, automated microscopy and sonic anemometry provided size-resolved estimates of both the inertial and gravitational components of the quasi-laminar layer particle deposition velocity, ( Vd) b, as a function of size. Eddy inertial deposition efficiency ( ηdI) was determined as a function of dimensionless eddy Stokes number (Stk e). In the range 3PNL-SA-6721, Pacific Northwest Laboratories, Richland, WA), used in several regulatory models, significantly under-predicted (up to seven times) ( Vd) b for large particles ( da>10 μm).

  14. Estimation of dry deposition fluxes of major inorganic species by canopy throughfall approach

    Institute of Scientific and Technical Information of China (English)

    JIN Lei; SHAO Min; ZENG Limin; ZHAO Dawei; TANG Dagang

    2006-01-01

    Dry deposition in China has not yet been intensively studied even though it constitutes an important pathway for acid deposition. The total deposition was monitored at Tieshanping catchment, a regional remote site in Chongqing City. The dry deposition loads of sulphur, calcium and nitrogen are estimated by using a canopy throughfall approach. The results indicate that the annual dry deposition loads of sulphur and calcium at Tieshanping site are much higher than those measured in forestry areas in other countries, while the dry deposition flux of nitrogen is at a comparable level. The dry deposition loads of sulphur, calcium and nitrogen are all higher than the wet deposition loads. Applying a canopy budget model has proven that the routine, simplified canopy throughfall approach may underestimate the dry deposition flux of nitrogen-containing species.

  15. Effect of SO2 Dry Deposition on Porous Dolomitic Limestones

    Science.gov (United States)

    Olaru, Mihaela; Aflori, Magdalena; Simionescu, Bogdana; Doroftei, Florica; Stratulat, Lacramioara

    2010-01-01

    The present study is concerned with the assessment of the relative resistance of a monumental dolomitic limestone (Laspra – Spain) used as building material in stone monuments and submitted to artificial ageing by SO2 dry deposition in the presence of humidity. To investigate the protection efficiency of different polymeric coatings, three commercially available siloxane-based oligomers (Lotexan-N, Silres BS 290 and Tegosivin HL 100) and a newly synthesized hybrid nanocomposite with silsesquioxane units (TMSPMA) were used. A comparative assessment of the data obtained in this study underlines that a better limestone protection was obtained when treated with the hybrid nanocomposite with silsesquioxane units.

  16. Effect of SO2 Dry Deposition on Porous Dolomitic Limestones

    Directory of Open Access Journals (Sweden)

    Florica Doroftei

    2010-01-01

    Full Text Available The present study is concerned with the assessment of the relative resistance of a monumental dolomitic limestone (Laspra – Spain used as building material in stone monuments and submitted to artificial ageing by SO2 dry deposition in the presence of humidity. To investigate the protection efficiency of different polymeric coatings, three commercially available siloxane-based oligomers (Lotexan-N, Silres BS 290 and Tegosivin HL 100 and a newly synthesized hybrid nanocomposite with silsesquioxane units (TMSPMA were used. A comparative assessment of the data obtained in this study underlines that a better limestone protection was obtained when treated with the hybrid nanocomposite with silsesquioxane units.

  17. Particle dry deposition to water surfaces: Processes and consequences

    DEFF Research Database (Denmark)

    Pryor, S.C.; Barthelmie, R.J.

    2000-01-01

    's oceans and seas is most significantly impacted by human activities. More than half of the world's population lives within 100 km of a coast and hence the overwhelming majority of anthropogenic fluxes to aquatic systems occur in the coastal zone. We discuss the particular challenges that arise from...... measurement requirements represent significant barriers to application to measurement of particle dry deposition fluxes although, as discussed, innovative solutions are now becoming available. In the final section, we examine meteorological controls on deposition to the coastal zone. This region of the world...... flux to coastal waters, atmosphere-surface exchange represents a significant component of the total flux and may be particularly critical during the summertime when both the riverine input and ambient nutrient concentrations are often at a minimum. In this chapter, we present an overview...

  18. Simulating ozone dry deposition at a boreal forest with a multi-layer canopy deposition model

    Science.gov (United States)

    Zhou, Putian; Ganzeveld, Laurens; Rannik, Üllar; Zhou, Luxi; Gierens, Rosa; Taipale, Ditte; Mammarella, Ivan; Boy, Michael

    2017-01-01

    A multi-layer ozone (O3) dry deposition model has been implemented into SOSAA (a model to Simulate the concentrations of Organic vapours, Sulphuric Acid and Aerosols) to improve the representation of O3 concentration and flux within and above the forest canopy in the planetary boundary layer. We aim to predict the O3 uptake by a boreal forest canopy under varying environmental conditions and analyse the influence of different factors on total O3 uptake by the canopy as well as the vertical distribution of deposition sinks inside the canopy. The newly implemented dry deposition model was validated by an extensive comparison of simulated and observed O3 turbulent fluxes and concentration profiles within and above the boreal forest canopy at SMEAR II (Station to Measure Ecosystem-Atmosphere Relations II) in Hyytiälä, Finland, in August 2010. In this model, the fraction of wet surface on vegetation leaves was parametrised according to the ambient relative humidity (RH). Model results showed that when RH was larger than 70 % the O3 uptake onto wet skin contributed ˜ 51 % to the total deposition during nighttime and ˜ 19 % during daytime. The overall contribution of soil uptake was estimated about 36 %. The contribution of sub-canopy deposition below 4.2 m was modelled to be ˜ 38 % of the total O3 deposition during daytime, which was similar to the contribution reported in previous studies. The chemical contribution to O3 removal was evaluated directly in the model simulations. According to the simulated averaged diurnal cycle the net chemical production of O3 compensated up to ˜ 4 % of dry deposition loss from about 06:00 to 15:00 LT. During nighttime, the net chemical loss of O3 further enhanced removal by dry deposition by a maximum ˜ 9 %. Thus the results indicated an overall relatively small contribution of airborne chemical processes to O3 removal at this site.

  19. Characterizing dry deposition of mercury in urban runoff

    Science.gov (United States)

    Fulkerson, M.; Nnadi, F.N.; Chasar, L.S.

    2007-01-01

    Stormwater runoff from urban surfaces often contains elevated levels of toxic metals. When discharged directly into water bodies, these pollutants degrade water quality and impact aquatic life and human health. In this study, the composition of impervious surface runoff and associated rainfall was investigated for several storm events at an urban site in Orlando, Florida. Total mercury in runoff consisted of 58% particulate and 42% filtered forms. Concentration comparisons at the start and end of runoff events indicate that about 85% of particulate total mercury and 93% of particulate methylmercury were removed from the surface before runoff ended. Filtered mercury concentrations showed less than 50% reduction of both total and methylmercury from first flush to final flush. Direct comparison between rainfall and runoff at this urban site indicates dry deposition accounted for 22% of total inorganic mercury in runoff. ?? 2007 Springer Science+Business Media B.V.

  20. Monitoring dry deposition of gases and particles over a forest

    Science.gov (United States)

    Mennen, M. G.; van Putten, E. M.; Uiterwijk, J. W.; Hogenkamp, J. E. M.; Wiese, C. J.; Draaijers, G.; Erisman, J. W.; Otjes, R. P.; Wyers, G. P.

    1996-12-01

    Dry deposition fluxes of acidifying and eutrophying compounds are continuously determined at Speulder forest, a Douglas fir site in the centre of the Netherlands. The monitoring equipment, installed on a 36-m high tower, consists of a sonic anemometer, a cup anemometer, a wind vane, a Bowen ratio system, three temperature/r.h. sensors, and gas analyzers to measure gradients of SO 2, NO x and NH 3 and concentrations of HCl, HNO 2 and HNO 3. Particles are sampled in two size ranges (<2.5 mm and 2.5-10 mm) on filters, which are analysed for acidifying components and basic cations. Fluxes of SO 2, NO x and NH 3 are determined with the gradient method, while fluxes of the other components are estimated with the inferential method. Parameterizations of the surface resistance ( Rc) for gases are derived from measurements obtained during periods that meet criteria with respect to homogeneous fetch, stationary flow, etc. Parameterized Rc values are used to estimate fluxes during periods that don't fulfil these demands. In this way, yearly average fluxes can be determined. In 1995, the total deposition fluxes of SO x(=SO 2+SO 42-), NO y(=NO x+NO 3-+HNO 2+HNO 3) and NH x, (=NH 3+NH 4+) were 450, 630 and 1620 eq. ha -1 a -1, respectively.

  1. Accuracy of cuticular resistance parameterizations in ammonia dry deposition models

    Science.gov (United States)

    Schrader, Frederik; Brümmer, Christian; Richter, Undine; Fléchard, Chris; Wichink Kruit, Roy; Erisman, Jan Willem

    2016-04-01

    Accurate representation of total reactive nitrogen (Nr) exchange between ecosystems and the atmosphere is a crucial part of modern air quality models. However, bi-directional exchange of ammonia (NH3), the dominant Nr species in agricultural landscapes, still poses a major source of uncertainty in these models, where especially the treatment of non-stomatal pathways (e.g. exchange with wet leaf surfaces or the ground layer) can be challenging. While complex dynamic leaf surface chemistry models have been shown to successfully reproduce measured ammonia fluxes on the field scale, computational restraints and the lack of necessary input data have so far limited their application in larger scale simulations. A variety of different approaches to modelling dry deposition to leaf surfaces with simplified steady-state parameterizations have therefore arisen in the recent literature. We present a performance assessment of selected cuticular resistance parameterizations by comparing them with ammonia deposition measurements by means of eddy covariance (EC) and the aerodynamic gradient method (AGM) at a number of semi-natural and grassland sites in Europe. First results indicate that using a state-of-the-art uni-directional approach tends to overestimate and using a bi-directional cuticular compensation point approach tends to underestimate cuticular resistance in some cases, consequently leading to systematic errors in the resulting flux estimates. Using the uni-directional model, situations where low ratios of total atmospheric acids to NH3 concentration occur lead to fairly high minimum cuticular resistances, limiting predicted downward fluxes in conditions usually favouring deposition. On the other hand, the bi-directional model used here features a seasonal cycle of external leaf surface emission potentials that can lead to comparably low effective resistance estimates under warm and wet conditions, when in practice an expected increase in the compensation point due to

  2. Evaluation and intercomparison of five major dry deposition algorithms in North America

    Science.gov (United States)

    Dry deposition of various pollutants needs to be quantified in air quality monitoring networks as well as in chemical transport models. The inferential method is the most commonly used approach in which the dry deposition velocity (Vd) is empirically parameterized as a function o...

  3. 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.

  4. Influence of Rough Flow over Sea Surface on Dry Atmospheric Deposition Velocities

    Directory of Open Access Journals (Sweden)

    Yan Zhang

    2013-01-01

    Full Text Available A Meteorological model and a dry deposition module were used to estimate the effects of sea surface rough flow (SSRF over the sea surface on dry deposition velocities. The dry deposition turbulence resistance, Ra, and sub-layer resistance, Rb, decreased more than 10% and 5% due to SSRF, respectively. For example, for HNO3, the mean dry deposition velocities (Vd were 0.51 cm s-1 in January, 0.58 in April, 0.65 cm s-1 in July and 0.79 cm s-1 in October with only smooth flow over the sea surface. However, the SSRF increased the Vd of HNO3 by 5 - 20% in the east China seas. These results show that SSRF is an important factor in estimating surface roughness to further improve calculation of the dry deposition velocities over the ocean. Improvements in parameterization of sea roughness length will be a worthwhile effort in related future studies.

  5. The impact of drought on ozone dry deposition over eastern Texas

    Science.gov (United States)

    Huang, Ling; McDonald-Buller, Elena C.; McGaughey, Gary; Kimura, Yosuke; Allen, David T.

    2016-02-01

    Dry deposition represents a critical pathway through which ground-level ozone is removed from the atmosphere. Understanding the effects of drought on ozone dry deposition is essential for air quality modeling and management in regions of the world with recurring droughts. This work applied the widely used Zhang dry deposition algorithm to examine seasonal and interannual changes in estimated ozone dry deposition velocities and component resistances/conductances over eastern Texas during years with drought (2006 and 2011) as well as a year with slightly cooler temperatures and above average rainfall (2007). Simulated area-averaged daytime ozone dry deposition velocities ranged between 0.26 and 0.47 cm/s. Seasonal patterns reflected the combined seasonal variations in non-stomatal and stomatal deposition pathways. Daytime ozone dry deposition velocities during the growing season were consistently larger during 2007 compared to 2006 and 2011. These differences were associated with differences in stomatal conductances and were most pronounced in forested areas. Reductions in stomatal conductances under drought conditions were highly sensitive to increases in vapor pressure deficit and warmer temperatures in Zhang's algorithm. Reductions in daytime ozone deposition velocities and deposition mass during drought years were associated with estimates of higher surface ozone concentrations.

  6. Speciated particle dry deposition to the sea surface: Results from ASEPS '97

    DEFF Research Database (Denmark)

    Pryor, S.C.; Barthelmie, R.J.; Geernaert, L.L.S.

    1999-01-01

    It has been postulated that atmospheric pathways may comprise a significant source of nitrogen for aquatic ecosystems and excess atmospheric deposition to coastal areas may be a major cause of eutrophication. Dry deposition of nitrogen containing particles is a potential, but poorly quantified...... on Precipitation Scavenging and Atmosphere-Surface Exchange Processes. AMS, Richland, Washington, USA, 12pp.) model to calculate size-segregated dry deposition of particle inorganic nitrogen compounds to the western Baltic during the late Spring of 1997 based on data collected as part of the Air-Sea Exchange...... Process Study (ASEPS). The results show that over a 15 d period in April and May dry deposition fluxes varied between 30 and 400 mu g m(-2) d(-1) for nitrate and 1 and 120 mu g m(-2) d(-1) for ammonium. Sensitivity analyses run to assess the potential bounds on actual dry deposition indicate that...

  7. 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

  8. Atmospheric trace elements at Enewetak Atoll: 2. Transport to the ocean by wet and dry deposition

    Science.gov (United States)

    Arimoto, R.; Duce, R. A.; Ray, B. J.; Unni, C. K.

    1985-02-01

    The concentrations of trace elements in precipitation and dry deposition are presented for samples collected at Enewetak Atoll (11°N, 162° E) during SEAREX experiments in 1979. The concentrations of Al, Sc, Mn, Fe, Co, and Th in rain are dominated by crustal material, and for these elements, wet deposition evidently exceeds dry deposition. For most of these elements the present rates of atmospheric deposition at Enewetak are similar to their mean rate of accumulation in sediments over the past 5-10,000 years, suggesting that the air-to-sea exchange of particles is closely tied to the sedimentary cycle of the mid-Pacific. Noncrustal sources govern the concentrations of Pb, Zn, Cu, Se, and Cd in wet and dry deposition samples. Analyses of dry deposition collected from a flat plastic plate indicate that the amount of material recycled from the sea surface varies markedly between samples, and even though these estimates do not necessarily reflect the dry deposition to the ocean surface, the results suggest that recycled sea spray often amounts to more than 50% of the total dry deposition of the enriched elements. Recycled sea spray also makes up a significant fraction of the total wet deposition of the enriched elements. The net deposition rates of elements such as Cu and Zn are greater than or equal to their inputs from vertical mixing, but the net deposition of Pb clearly exceeds the input from upwelling. The current net deposition rates of the enriched elements are also similar to their rates of removal to sediments. These results indicate that air-sea exchange processes may significantly affect the chemistry of trace metals in the open ocean.

  9. The estimated six-year mercury dry deposition across North America

    Science.gov (United States)

    Zhang, Leiming; Wu, Zhiyong; Cheng, Irene; Wright, L. Paige; Olson, Mark L.; Gay, David A.; Risch, Martin R.; Brooks, Steven; Castro, Mark S.; Conley, Gary D.; Edgerton, Eric S.; Holsen, Thomas M.; Luke, Winston; Tordon, Robert; Weiss-Penzias, Peter

    2016-01-01

    Dry deposition of atmospheric mercury (Hg) to various land covers surrounding 24 sites in North America was estimated for the years 2009 to 2014. Depending on location, multiyear mean annual Hg dry deposition was estimated to range from 5.1 to 23.8 μg m–2 yr–1 to forested canopies, 2.6 to 20.8 μg m–2 yr–1 to nonforest vegetated canopies, 2.4 to 11.2 μg m–2 yr–1 to urban and built up land covers, and 1.0 to 3.2 μg m–2 yr–1 to water surfaces. In the rural or remote environment in North America, annual Hg dry deposition to vegetated surfaces is dominated by leaf uptake of gaseous elemental mercury (GEM), contrary to what was commonly assumed in earlier studies which frequently omitted GEM dry deposition as an important process. Dry deposition exceeded wet deposition by a large margin in all of the seasons except in the summer at the majority of the sites. GEM dry deposition over vegetated surfaces will not decrease at the same pace, and sometimes may even increase with decreasing anthropogenic emissions, suggesting that Hg emission reductions should be a long-term policy sustained by global cooperation.

  10. Foliar loading and metabolic assimilation of dry deposited nitric acid air pollutants by trees.

    Science.gov (United States)

    Padgett, Pamela E; Cook, Hillary; Bytnerowicz, Andrzej; Heath, Robert L

    2009-01-01

    Dry deposition of nitric acid vapor (HNO(3)) is a major contributor to eutrophication of natural ecosystems. Although soil fertilization by nitrogen deposition is considered to be the primary pathway for changes in plant nutrient status and shifts in ecological structure, the aerial portion of plants offer many times the surface area in which to collect atmospheric HNO(3). As much as 60% of deposited nitrogen may be retained in the canopy and not land on the soil surface below. Although uptake and assimilation appears to contribute to retention, only a small percentage of dry deposition is recovered in assimilated N pools. To test the importance of biological activity on the process and measurements of dry deposition, we used controlled environmental chambers to compare deposition to living and freeze-dried foliage of four tree species using (15)N-labeled HNO(3). In living trees, assimilation was determined by (15)N incorporation into free amino acids and proteins in leaves and roots. From 10% to 60% of the retained HNO(3) was incorporated into the biologically active nitrogen pool. The remainder was bound to foliar surfaces in an insoluble form in either living or freeze-dried foliage. The importance of the boundary layer conditions emerged as a primary factor controlling dry deposition characteristics and measurements.Trade names and commercial enterprises or products are mentioned solely for information. No endorsements by the U.S. Department of Agriculture are implied.

  11. Dry deposition of sulphur on the Mpumalanga highveld: a pilot study using the inferential method

    CSIR Research Space (South Africa)

    Zunckel, M

    1996-10-01

    Full Text Available A pilot study which uses the inferential method to estimate dry deposition of sulphur on the central Mpumalanga highveld is discussed in this paper. Ambient concentrations of sulphur dioxide, particulates and micro-meteorological measurements from 2...

  12. Dry 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 dry deposition of reduced nitrogen in the Pacific Northwest region...

  13. Dry deposition velocity of total suspended particles and meteorological influence in four locations in Guangzhou, China

    Institute of Scientific and Technical Information of China (English)

    Leifu Chen; Shaolin Peng; Jingang Liu; Qianqian Hou

    2012-01-01

    Dry deposition velocity of total suspended particles (TSP) is an effective parameter that describes the speed of atmospheric particulate matter deposit to the natural surface.It is also an important indicator to the capacity of atmosphere self-depuration.However,the spatial and temporal variations in dry deposition velocity of TSP at different urban landscapes and the relationship between dry deposition velocity and the meteorological parameters are subject to large uncertainties.We concurrently investigated this relationship at four different landscapes of Guangzhou,from October to December of 2009.The result of the average dry deposition velocity is (1.49 ±0.77),(1.44 ± 0.77),(1.13 ± 0.53) and (1.82 ± 0.82) cm/sec for urban commercial landscape,urban forest landscape,urban residential landscape and country landscape,respectively.This spatial variation can be explained by the difference of both particle size composition of TSP and meteorological parameters of sampling sites.Dry deposition velocity of TSP has a positive correlation with wind speed,and a negative correlation with temperature and relative humidity.Wind speed is the strongest factor that affects the magnitude of TSP dry deposition velocity,and the temperature is another considerable strong meteorological factor.We also find out that the relative humidity brings less impact,especially during the dry season.It is thus implied that the current global warming and urban heat island effect may lead to correlative changes in TSP dry deposition velocity,especially in the urban areas.

  14. Improved Formulations for Air-Surface Exchanges Related to National Security Needs: Dry Deposition Models

    Energy Technology Data Exchange (ETDEWEB)

    Droppo, James G.

    2006-07-01

    The Department of Homeland Security and others rely on results from atmospheric dispersion models for threat evaluation, event management, and post-event analyses. The ability to simulate dry deposition rates is a crucial part of our emergency preparedness capabilities. Deposited materials pose potential hazards from radioactive shine, inhalation, and ingestion pathways. A reliable characterization of these potential exposures is critical for management and mitigation of these hazards. A review of the current status of dry deposition formulations used in these atmospheric dispersion models was conducted. The formulations for dry deposition of particulate materials from am event such as a radiological attack involving a Radiological Detonation Device (RDD) is considered. The results of this effort are applicable to current emergency preparedness capabilities such as are deployed in the Interagency Modeling and Atmospheric Assessment Center (IMAAC), other similar national/regional emergency response systems, and standalone emergency response models. The review concludes that dry deposition formulations need to consider the full range of particle sizes including: 1) the accumulation mode range (0.1 to 1 micron diameter) and its minimum in deposition velocity, 2) smaller particles (less than .01 micron diameter) deposited mainly by molecular diffusion, 3) 10 to 50 micron diameter particles deposited mainly by impaction and gravitational settling, and 4) larger particles (greater than 100 micron diameter) deposited mainly by gravitational settling. The effects of the local turbulence intensity, particle characteristics, and surface element properties must also be addressed in the formulations. Specific areas for improvements in the dry deposition formulations are 1) capability of simulating near-field dry deposition patterns, 2) capability of addressing the full range of potential particle properties, 3) incorporation of particle surface retention/rebound processes, and

  15. Dry deposition and resuspension of particle-associated metals near a freeway in Los Angeles

    Science.gov (United States)

    Sabin, Lisa D.; Hee Lim, Jeong; Teresa Venezia, Maria; Winer, Arthur M.; Schiff, Kenneth C.; Stolzenbach, Keith D.

    Dry atmospheric deposition represents a potentially large source of pollutant metal contamination in urban stormwater runoff, yet there is a limited amount of research on the relationship between atmospheric emissions and water quality problems in urban areas. In Los Angeles, with air quality that ranks among the worst in the United States, significant quantities of toxic materials are released into the atmosphere every day, and paved road dust represents the largest source of particle-associated metal emissions to the atmosphere. In order to better understand the role of roadways as a source of localized metal deposition, we characterized the horizontal dry deposition patterns of chromium, copper, lead, nickel and zinc upwind and at increasing distances downwind of the I-405 Freeway in coastal Los Angeles. Dry deposition fluxes and atmospheric concentrations of these metals were highest at the site closest to the freeway, and reduced to approximately urban background concentrations between 10 and 150 m downwind of the freeway. Compared with urban background, atmospheric particle size distributions indicated the freeway was a significant source of these metals on large particles >6 μm in diameter, which deposit close to their source and account for the increased dry deposition flux rates observed near the freeway. The spatial pattern of measured deposition flux was well predicted by a relatively simple line-source Gaussian plume model modified to include particle deposition and resuspension. The model results indicated dilution by vertical dispersion of the plume was the most important mechanism regulating downwind concentrations and deposition.

  16. 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

  17. Wet and dry deposition of atmospheric nitrogen at ten sites in Northern China

    Directory of Open Access Journals (Sweden)

    Y. P. Pan

    2012-01-01

    Full Text Available Emissions of reactive nitrogen (N species can affect surrounding ecosystems via atmospheric deposition. However, few long-term and multi-site measurements have focused on both the wet and the dry deposition of individual N species in large areas of Northern China. Thus, the magnitude of atmospheric deposition of various N species in Northern China remains uncertain. In this study, the wet and dry atmospheric deposition of different N species was investigated during a three-year observation campaign at ten selected sites in Northern China. The results indicate that N deposition levels in Northern China were high with a ten-site, three-year average of 60.6 kg N ha−1 yr−1. The deposition levels showed spatial and temporal variation in the range of 28.5–100.4 kg N ha−1 yr−1. Of the annual total deposition, 40% was deposited via precipitation, and the remaining 60% was comprised of dry-deposited forms. Compared with gaseous N species, particulate N species were not the major contributor of dry-deposited N; they contributed approximately 10% to the total flux. On an annual basis, oxidized species accounted for 21% of total N deposition, thereby implying that other forms of gaseous N, such as NH3, comprised a dominant portion of the total flux. The contribution of NO3 to N deposition was enhanced in certain urban and industrial areas. As expected, the total N deposition in Northern China was significantly larger than the values reported by national scale monitoring networks in Europe, North America and East Asia because of high rates of wet deposition and gaseous NH3 dry deposition. The results have three important implications. First, atmospheric N deposition in Northern China falls within the range of critical loads for temperate forests and grasslands, a threshold above which harmful ecological effects to specified parts of temperate ecosystems often

  18. Dry deposition parameterization of sulfur oxides in a chemistry and general circulation

    NARCIS (Netherlands)

    Ganzeveld, L.N.; Lelieveld, J.; Roelofs, G.J.

    1998-01-01

    A dry deposition scheme, originally developed to calculate the deposition velocities for the trace gases O3, NO2, NO, and HNO3 in the chemistry and general circulation European Centre Hamburg Model (ECHAM), is extended to sulfur dioxide (SO2) and sulfate (SO42-). In order to reduce some of the short

  19. Phenological controls on inter-annual variability in ozone dry deposition velocity

    Science.gov (United States)

    Clifton, Olivia; Fiore, Arlene; Munger, J. William; Shevliakova, Elena; Horowitz, Larry; Malyshev, Sergey; Griffin, Kevin

    2016-04-01

    Our understanding of ozone removal by northern mid-latitude temperate deciduous forests is largely based on short-term observational studies, and thus year-to-year variations of this sink have received little attention. The specific pathways for ozone dry deposition include stomatal uptake and other non-stomatal processes that are poorly understood. Given the importance of ozone dry deposition to model accurately the tropospheric ozone budget and regional air quality, an improved mechanistic understanding of this ozone sink is needed. We investigate here the physical and biological controls on inter-annual variations in seasonal and diurnal cycles of ozone dry deposition velocity using nine years of hourly observations of eddy covariance ozone flux and concentration measurements at Harvard Forest, a northern mid-latitude temperate deciduous forest. We also use coincident eddy covariance water vapor flux and sensible heat flux and other micrometeorological measurements to infer stomatal conductance in order to separate the impacts of stomatal versus non-stomatal pathways on ozone deposition. There is a difference of approximately a factor of two between minimum and maximum monthly daytime mean ozone dry deposition velocities at Harvard Forest. The highest summertime mean ozone dry deposition velocities occur during 1998 and 1999 (0.72 cm/s), and similar seasonal and diurnal cycles occur in both years. The similar dry deposition velocities during these two years, however, may reflect compensation between different processes as mean daytime summertime stomatal conductance during 1998 is roughly 1.5 times higher than for 1999, suggesting large year-to-year variations in non-stomatal as well as stomatal uptake of ozone. We partition the onset and decline of the growing season each year into different periods using spring and fall phenology observations at Harvard Forest. Combining the dry deposition velocities across years during each phenological period, we find that

  20. Modeling dry deposition of reactive nitrogen in China with RAMS-CMAQ

    Science.gov (United States)

    Han, Xiao; Zhang, Meigen; Skorokhod, Andrei; Kou, Xingxia

    2017-10-01

    China has the world highest production of reactive nitrogen (Nr), and the Nr consumption increased sharply during the last decade. However, the potential environmental influence of dry nitrogen (N) deposition in China remains uncertain due to that the long-term measurement or remote sensing of various N species are difficult. This requires a better understanding of dry N deposition over China in its various forms and including magnitude and distribution features. Thus, the air quality modeling system RAMS-CMAQ was applied to simulate dry deposition of Nr over China from 2010 to 2014. The model results were then analyzed to investigate the long-term spatial and temporal distributions of major inorganic nitrogen (N) components (10 species) and selected organic N components (5 species). Comparisons between modeled and observed deposition rates and surface mass concentrations showed generally good agreement. Model results indicated a total dry N deposition budget of 9.31 Tg N yr-1 in China, including 4.29 Tg N yr-1 as NOy and 4.43 Tg N yr-1 as NH3. NOy was the main component of dry N deposition in the Beijing-Tianjin-Hebei area (0.31 Tg N yr-1), the Yangtze River Delta (0.29 Tg N yr-1), and the Pearl River Delta (0.09 Tg N yr-1), where the major megacity clusters of China are located. NH3 was the main component of dry N deposition in Shandong province (0.24 Tg N yr-1), Northeast China (0.46 Tg N yr-1), the Sichuan Basin (0.48 Tg N yr-1), and central China (0.95 Tg N yr-1), where the major agricultural regions are located. The highest values of the deposition flux for NH3 occurred in Shandong province (19.40 kg N ha-1 yr-1) and Beijing-Tianjin-Hebei (17.20 kg N ha-1 yr-1). The seasonal variation of total dry N deposition was obvious in the east part of China, and was higher in July and lower in January. The spatio-temporal variations and major sources of dry N deposition were strongly heterogeneous, implying that the comprehensive pollution control strategies should be

  1. Magma ascent, fragmentation and depositional characteristics of "dry" maar volcanoes: Similarities with vent-facies kimberlite deposits

    Science.gov (United States)

    Berghuijs, Jaap F.; Mattsson, Hannes B.

    2013-02-01

    Several maar craters within the Lake Natron-Engaruka monogenetic volcanic field (LNE-MVF) of northern Tanzania show compelling evidence for magmatic fragmentation and dry deposition. This is in contradiction of the common belief that most maars are formed through the explosive interaction between ascending magma and ground- or surface water. We here present a detailed study on the eruptive and depositional characteristics of the Loolmurwak and Eledoi maar volcanoes, two of the largest craters in the LNE-MVF, focusing on high-resolution stratigraphy, sedimentology, grain size distribution, pyroclast textures and morphologies, bulk geochemistry and mineral chemistry. At both maars, ejected material has been emplaced by a combination of pyroclastic surges and fallout. Indicators of phreatomagmatic fragmentation and wet deposition, such as impact sags, accretionary lapilli, vesiculated tuffs and plastering against obstacles, are absent in the deposits. Juvenile material predominantly occurs as fluidal-shaped vesicular melt droplets and contains no glass shards produced by the breakage of bubble walls. The Eledoi deposits comprise a large amount of inversely graded beds and lenses, which result from grain flow in a dry depositional environment. Preferential deposition of fine material toward the northern side of its crater can be related to effective wind winnowing in a dry eruption plume. This large variety of observations testifies to the dominance of magmatic fragmentation as well as dry deposition at the Loolmurwak and Eledoi maars, which is in line with what has been found for other structures in the LNE-MVF but contrasts with current ideas on maar formation. We infer that a volatile-rich, olivine melilitic magma was formed by small amounts of partial melting at upper mantle depths. With minimum average ascent rates of 5.3 m s- 1 for Loolmurwak and 26.2 m s- 1 for Eledoi, this magma rapidly moved toward the surface and exsolved a substantial amount of volatiles

  2. Dry deposition of particulate matter at an urban forest, wetland and lake surface in Beijing

    Science.gov (United States)

    Liu, Jiakai; Zhu, Lijuan; Wang, Huihui; Yang, Yilian; Liu, Jiatong; Qiu, Dongdong; Ma, Wu; Zhang, Zhenming; Liu, Jinglan

    2016-01-01

    The dry deposition of particular matters from atmosphere to ecosystems is an undesirable consequence of this pollution while the deposition process is also influenced by different land use types. In current study, concentration of fine particles, coarse particles and meteorological data were collected during the daytime in an artificial forest, wetland and a water surface in the Beijing Olympic Park. Dry deposition velocity, fluxes and vegetation collection were calculated by different models and the results were compared. The results show: (1) the deposition velocity onto the forest canopy was higher than which onto the wetland and the water surface and the velocity varied in different seasons; (2) the fine particles deposited most in the winter while the coarse particles was in the spring; (3) the vegetation collection rates of fine particles were lower than coarse particles, and the forest collected more PMs than the wetland plants.

  3. Modelling atmospheric dry deposition in urban areas using an urban canopy approach

    Directory of Open Access Journals (Sweden)

    N. Cherin

    2014-12-01

    Full Text Available Atmospheric dry deposition is typically modelled using an average roughness length, which depends on land use. This classical roughness-length approach cannot account for the spatial variability of dry deposition in complex settings such as urban areas. Urban canopy models have been developed to parametrise momentum and heat transfer. We extend this approach here to mass transfer and a new dry deposition model based on the urban canyon concept is presented. It uses a local mixing length parametrisation of turbulence within the canopy, and a description of the urban canopy via key parameters to provide spatially-distributed dry deposition fluxes. Three different flow regimes are distinguished in the urban canyon depending on the height-to-width ratio of built areas: isolated roughness flow, wake interference flow and skimming flow. Differences between the classical roughness-length model and the model developed here are investigated. Sensitivity to key parameters are discussed. This approach provides spatially-distributed dry deposition fluxes that depend on surfaces (streets, walls, roofs and flow regimes (recirculation and ventilation within the urban area.

  4. Modelling atmospheric dry deposition in urban areas using an urban canopy approach

    Directory of Open Access Journals (Sweden)

    N. Cherin

    2015-03-01

    Full Text Available Atmospheric dry deposition is typically modelled using an average roughness length, which depends on land use. This classical roughness-length approach cannot account for the spatial variability of dry deposition in complex settings such as urban areas. Urban canopy models have been developed to parametrise momentum and heat transfer. We extend this approach here to mass transfer, and a new dry deposition model based on the urban canyon concept is presented. It uses a local mixing-length parametrisation of turbulence within the canopy, and a description of the urban canopy via key parameters to provide spatially distributed dry deposition fluxes. Three different flow regimes are distinguished in the urban canyon depending on the height-to-width ratio of built areas: isolated roughness flow, wake interference flow and skimming flow. Differences between the classical roughness-length model and the model developed here are investigated. Sensitivity to key parameters are discussed. This approach provides spatially distributed dry deposition fluxes that depend on surfaces (streets, walls, roofs and flow regimes (recirculation and ventilation within the urban area.

  5. Dispersion and dry and wet deposition of PAHs in an atmospheric environment.

    Science.gov (United States)

    Ozaki, N; Nitta, K; Fukushima, T

    2006-01-01

    The atmospheric concentration and dry and wet deposition were measured for particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) from August to December in Higashi-Hiroshima City, Japan. PM concentration of fine particles (0.6-7 microm) was 5.7-75.1 micro m(-3), and coarse particles (> 7 microm) was 2.2-22.3 microg m(-3). Total PAHs concentration of fine particles was 0.14-16.3 ng m(-3), and coarse particles was 0.01-0.77 ng m(-3). Their concentration increased on non-rainy days and decreased rapidly on rainy days. For seasonal fluctuations of PAHs, their concentrations decreased from summer to winter, and the rate of decrease was more distinct for fine particles. For total (dry + wet) depositions, the PM flux was 1.9-11.2 mg m(-2) d(-1), and the total PAHs flux was 1.9-97.2 ng m(-3) d(-1). From these measurements, the yearly total loading of PAHs was estimated for the particle phase. Total loading was 28 microg m(-2) y(-1) for the dry deposition and 52 mg m(-2) y(-1) for the wet deposition. The loading of the wet deposition was comparable to those of the dry deposition for all ring numbers.

  6. Dry Deposition of Polycyclic Aromatic Hydrocarbons (PAHs) at a Suburban Site in Beijing, China

    Science.gov (United States)

    Zhang, Xincheng; Wang, Weiyu; Zhu, Xianlei

    2017-04-01

    A great amount of polycyclic aromatic hydrocarbons (PAHs) have been generated by industrial production, waste incineration and landfill, traffic and road dust etc. They are emitted into atmosphere and afterwards enter into water body and soil through deposition, resulting in wide distribution of PAHs in environment. However, the dry deposition of PAHs from atmosphere has not been well studied, especially in the aspects of its characteristics, environmental and health effects, sources and mechanism. This study measured PAHs dry deposition in the northwest suburban area of Beijing. Dry deposition samples (i.e. dustfall samples) were collected at the sampling site located in China University of Petroleum - Beijing in 2012-2016. And PAHs in the samples were determined by GC/MS. The dry deposition flux of 16 US EPA priority PAHs (ΣPAH16) was 2.58 μg/(m^2·d), which was lower than those in other regions of North China. Its seasonal variability was more significant than annual variability (p spring > autumn > summer. The amount of ΣPAH16 removed from the atmosphere by dry deposition process accounted for only 1.2% of their emissions, indicating that the atmosphere self-purification capacity was quite limited and emission reduction measures would play a key role in controlling PAHs air pollution. However, PAHs dry deposition would deteriorate soil quality since the content of ΣPAH16 in dustfall was 1-2 orders of magnitude higher than that in soil in the same area. Dermal exposure resulting from PAHs dry deposition was not the major route. The sources of PAHs dry deposition varied with seasons. The profile and specific ratios of PAHs showed that in winter, domestic coal combustion was the main source of PAHs with the contribution up to 77%; in spring and summer, the impact of coal combustion decreased and the contribution of vehicle exhaust increased to 30% - 45%; in fall, in addition to coal combustion and vehicle exhaust, the impact of biomass burning was observed

  7. Wet and dry nitrogen deposition in the central Sichuan Basin of China

    Science.gov (United States)

    Kuang, Fuhong; Liu, Xuejun; Zhu, Bo; Shen, Jianlin; Pan, Yuepeng; Su, Minmin; Goulding, Keith

    2016-10-01

    Reactive nitrogen (Nr) plays a key role in the atmospheric environment and its deposition has induced large negative impacts on ecosystem health and services. Five-year continuous in-situ monitoring of N deposition, including wet (total nitrogen (WTN), total dissolved nitrogen (WTDN), dissolved organic nitrogen (WDON), ammonium nitrogen (WAN) and nitrate nitrogen (WNN)) and dry (DNH3, DHNO3, DpNH4+, DpNO3- and DNO2) deposition, had been conducted since August 2008 to December 2013 (wet) and May 2011 to December 2013 (dry) in Yan-ting, China, a typical agricultural area in the central Sichuan Basin. Mean annual total N deposition from 2011 to 2013 was 30.8 kg N ha-1 yr-1, and speculated that of 2009 and 2010 was averaged 28.2 kg N ha-1 yr-1, respectively. Wet and dry N deposition accounted for 76.3% and 23.7% of annual N deposition, respectively. Reduced N (WAN, DNH3 and DpNH4+) was 1.7 times of oxidized N (WNN, DHNO3, DNO2 and DpNO3-) which accounted for 50.9% and 30.3% of TN, respectively. Maximum loadings of all N forms of wet deposition, gaseous NH3, HNO3 and particulate NH4+ in dry deposition occurred in summer and minimum loadings in winter. Whether monthly, seasonal or annual averaged, dissolved N accounted for more than 70% of the total. N deposition in the central Sichuan Basin increased during the sampling period, especially that of ammonium compounds, and has become a serious threat to local aquatic ecosystems, the surrounding forest and other natural or semi-natural ecosystems in the upper reaches of the Yangtze River.

  8. Observation- and model-based estimates of particulate dry nitrogen deposition to the oceans

    Science.gov (United States)

    Baker, Alex R.; Kanakidou, Maria; Altieri, Katye E.; Daskalakis, Nikos; Okin, Gregory S.; Myriokefalitakis, Stelios; Dentener, Frank; Uematsu, Mitsuo; Sarin, Manmohan M.; Duce, Robert A.; Galloway, James N.; Keene, William C.; Singh, Arvind; Zamora, Lauren; Lamarque, Jean-Francois; Hsu, Shih-Chieh; Rohekar, Shital S.; Prospero, Joseph M.

    2017-07-01

    Anthropogenic nitrogen (N) emissions to the atmosphere have increased significantly the deposition of nitrate (NO3-) and ammonium (NH4+) to the surface waters of the open ocean, with potential impacts on marine productivity and the global carbon cycle. Global-scale understanding of the impacts of N deposition to the oceans is reliant on our ability to produce and validate models of nitrogen emission, atmospheric chemistry, transport and deposition. In this work, ˜ 2900 observations of aerosol NO3- and NH4+ concentrations, acquired from sampling aboard ships in the period 1995-2012, are used to assess the performance of modelled N concentration and deposition fields over the remote ocean. Three ocean regions (the eastern tropical North Atlantic, the northern Indian Ocean and northwest Pacific) were selected, in which the density and distribution of observational data were considered sufficient to provide effective comparison to model products. All of these study regions are affected by transport and deposition of mineral dust, which alters the deposition of N, due to uptake of nitrogen oxides (NOx) on mineral surfaces. Assessment of the impacts of atmospheric N deposition on the ocean requires atmospheric chemical transport models to report deposition fluxes; however, these fluxes cannot be measured over the ocean. Modelling studies such as the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP), which only report deposition flux, are therefore very difficult to validate for dry deposition. Here, the available observational data were averaged over a 5° × 5° grid and compared to ACCMIP dry deposition fluxes (ModDep) of oxidised N (NOy) and reduced N (NHx) and to the following parameters from the Tracer Model 4 of the Environmental Chemical Processes Laboratory (TM4): ModDep for NOy, NHx and particulate NO3- and NH4+, and surface-level particulate NO3- and NH4+ concentrations. As a model ensemble, ACCMIP can be expected to be more robust than

  9. Atmospheric dry deposition in the vicinity of the Salton Sea, California - I: Air pollution and deposition in a desert environment

    Science.gov (United States)

    Alonso, R.; Bytnerowicz, A.; Boarman, W.I.

    2005-01-01

    Air pollutant concentrations and atmospheric dry deposition were monitored seasonally at the Salton Sea, southern California. Measurements of ozone (O 3), nitric acid vapor (HNO3), ammonia (NH3), nitric oxide (NO), nitrogen dioxide (NO2) and sulfur dioxide (SO 2) were performed using passive samplers. Deposition rates of NO 3-, NH4+, Cl-, SO 42-, Na+, K+ and Ca2+ to creosote bush branches and nylon filters as surrogate surfaces were determined for one-week long exposure periods. Maximum O3 values were recorded in spring with 24-h average values of 108.8 ??g m-3. Concentrations of NO and NO2 were low and within ranges of the non-urban areas in California (0.4-5.6 and 3.3-16.2 ??g m-3 ranges, respectively). Concentrations of HNO3 (2.0-6.7 ??g m-3) and NH 3 (6.4-15.7 ??g m-3) were elevated and above the levels typical for remote locations in California. Deposition rates of Cl-, SO42-, Na+, K+ and Ca2+ were related to the influence of sea spray or to suspended soil particles, and no strong enrichments caused by ions originated by human activities were detected. Dry deposition rates of NO3- and NH4+ were similar to values registered in areas where symptoms of nitrogen saturation and changes in species composition have been described. Deposition of nitrogenous compounds might be contributing to eutrophication processes at the Salton Sea. ?? 2005 Elsevier Ltd. All rights reserved.

  10. Dry and wet deposition of polycyclic aromatic hydrocarbons and comparison with typical media in urban system of Shanghai, China

    Science.gov (United States)

    Wang, Qing; Liu, Min; Li, Ye; Liu, Yankun; Li, Shuwen; Ge, Rongrong

    2016-11-01

    Polycyclic aromatic hydrocarbons (PAHs) were studied in dry and wet deposition samples collected at urban and suburban sites of Shanghai, China from April 2014 to April 2015. Average wet deposition fluxes of PAHs were higher than dry deposition (62.6 ± 41.5 vs. 26.9 ± 14.4 μg/m2/day). However, dry deposition removed more PAHs than wet deposition (69% vs. 31%) due to much shorter durations of wet deposition. The highest dry and wet deposition fluxes were in fall and winter, respectively. The highest amount of dry deposition was in fall and the highest of wet deposition was in summer. The contribution of wet deposition to total deposited PAHs in Shanghai, East China was higher than that in northern China and lower than that in southern China. The difference can be explained by both precipitation amount and removal efficiency (washout ratio). Average dry deposition velocity and washout ratio of particle-associated PAHs were 5.2 cm/s and 5.8 × 104, respectively. Four sources of deposited PAHs were unraveled by positive matrix factorization (PMF) model: traffic, coal combustion, coking and volatilization, contributing 28.7%, 24.6%, 23.7% and 23.0%, respectively. More contribution of traffic and less coal combustion and volatilization were found at urban than at suburban site. As the connection between aerosol and surface soil, deposition had a different PAH composition from those in the two sides, containing more low MW PAHs. That arose the concern that dry deposition velocity and particle washout ratio could be overestimated if coarse particulate matter was excluded from the calculation. Although deposition has been considered as the predominant pathway of PAHs to urban surface system, the PAH composition in street dust differed drastically from that in deposition. This indicated that other sources (e.g. traffic) in urban system could have a greater contribution to PAHs than it had been identified in deposition samples.

  11. Optimized plasma-deposited fluorocarbon coating for dry release and passivation of thin SU-8 cantilevers

    DEFF Research Database (Denmark)

    Keller, Stephan Urs; Häfliger, Daniel; Boisen, Anja

    2008-01-01

    Plasma-deposited fluorocarbon coatings are introduced as a convenient method for the dry release of polymer structures. In this method, the passivation process in a deep reactive ion etch reactor was used to deposit hydrophobic fluorocarbon films. Standard photolithography with the negative epoxy......-based photoresist SU-8 was used to fabricate polymer structures such as cantilevers and membranes on top of the nonadhesive release layer. The authors identify the plasma density as the main parameter determining the surface properties of the deposited fluorocarbon films. They show that by modifying the pressure...

  12. Effect of atmospheric electricity on dry deposition of airborne particles from atmosphere

    Science.gov (United States)

    Tammet, H.; Kimmel, V.; Israelsson, S.

    The electric mechanism of dry deposition is well known in the case of unattached radon daughter clusters that are unipolar charged and of high mobility. The problematic role of the electric forces in deposition of aerosol particles is theoretically examined by comparing the fluxes of particles carried by different deposition mechanisms in a model situation. The electric mechanism of deposition appears essential for particles of diameter 10-200 nm in conditions of low wind speed. The electric flux of fine particles can be dominant on the tips of leaves and needles even in a moderate atmospheric electric field of a few hundred V m -1 measured over the plane ground surface. The electric deposition is enhanced under thunderclouds and high voltage power lines. Strong wind suppresses the relative role of the electric deposition when compared with aerodynamic deposition. When compared with diffusion deposition the electric deposition appears less uniform: the precipitation particulate matter on the tips of leaves and especially on needles of top branches of conifer trees is much more intensive than on the ground surface and electrically shielded surfaces of plants. The knowledge of deposition geometry could improve our understanding of air pollution damage to plants.

  13. Modeling of Ammonia Dry Deposition to a Pocosin Landscape Downwind of a Large Poultry Facility

    Science.gov (United States)

    A semi-empirical bi-directional flux modeling approach is used to estimate NH3 air concentrations and dry deposition fluxes to a portion of the Pocosin Lakes National Wildlife Refuge (PLNWR) downwind of a large poultry facility. Meteorological patterns at PLNWR are such that som...

  14. Measurement of the dry deposition flux of NH3 on to coniferous forest

    NARCIS (Netherlands)

    Duyzer, J.H.; Verhagen, H.L.M.; Weststrate, J.H.; Bosveld, F.C.

    1992-01-01

    The dry deposition flux of NH3 to coniferous forest was determined by the micrometeorological gradient method using a 36m high tower. Aerodynamic characteristics of the site were studied, using a second tower erected in the forest 100m from the first. Fluxes and gradients of heat and momentum measur

  15. Micrometeorological measurement of the dry deposition flux of sulphate and nitrate aerosols to coniferous forest

    NARCIS (Netherlands)

    Wyers, G.P.; Duyzer, J.H.

    1997-01-01

    Dry deposition fluxes of sulphate and nitrate have been determined over a coniferous canopy using the aerodynamic gradient technique. Vertical concentration gradients of sulphate and nitrate were measured with filters; the gradient of ammonium bisulphate was measured with thermodenuders. Filter meas

  16. Modeling of Ammonia Dry Deposition to a Pocosin Landscape Downwind of a Large Poultry Facility

    Science.gov (United States)

    A semi-empirical bi-directional flux modeling approach is used to estimate NH3 air concentrations and dry deposition fluxes to a portion of the Pocosin Lakes National Wildlife Refuge (PLNWR) downwind of a large poultry facility. Meteorological patterns at PLNWR are such that som...

  17. Aerosol dynamics within and above forest in relation to turbulent transport and dry deposition

    DEFF Research Database (Denmark)

    Rannik, Üllar; Zhou, Luxi; Zhou, Putian;

    2016-01-01

    of 10 days in May 2013 to a pine forest site in southern Finland. The period was characterized by frequent new particle formation events and simultaneous intensive aerosol transformation. The aim of the study was to analyze and quantify the role of aerosol and ABL dynamics in the vertical transport...... of aerosols. It was of particular interest to what extent the fluxes above the canopy deviate from the particle dry deposition on the canopy foliage due to the above-mentioned processes. The model simulations revealed that the particle concentration change due to aerosol dynamics frequently exceeded...... the effect of particle deposition by even an order of magnitude or more. The impact was, however, strongly dependent on particle size and time. In spite of the fact that the timescale of turbulent transfer inside the canopy is much smaller than the timescales of aerosol dynamics and dry deposition, leading...

  18. Atmospheric deposition of nitrogen over Czech forests: refinement of estimation of dry deposition for unmeasured nitrogen species

    Science.gov (United States)

    Hunova, Iva; Stoklasova, Petra; Kurfurst, Pavel; Vlcek, Ondrej; Schovankova, Jana

    2014-05-01

    The accurate quantification of atmospheric deposition is very important for assessment of ambient air pollution impacts on ecosystems. Our contribution presents an advanced approach to improved quantification of atmospheric deposition of nitrogen over Czech forests, merging available measured data and model results. The ambient air quality monitoring in the Czech Republic is paid an appreciable attention (Hůnová, 2001) due to the fact, that in the recent past its territory belonged to the most polluted parts of Europe (Moldan and Schnoor, 1992). The time trends and spatial patterns of atmospheric deposition were published (Hůnová et al. 2004, Hůnová et al. 2014). Nevertheless, it appears that the atmospheric deposition of nitrogen, particularly the dry deposition, is likely to be underestimated due to unavailability of data of certain nitrogen species as HNO3(g) and NH3. It is known that HNO3(g) may contribute significantly to the dry deposition of nitrogen even in regions with relatively low concentrations (Flechard et al., 2011). We attempted to substitute unmeasured nitrogen species using an Eulerian photochemical dispersion model CAMx, the Comprehensive Air Quality Model with extensions (ESSS, 2011), coupled with a high resolution regional numeric weather prediction model Aladin (Vlček, Corbet, 2011). Preliminary results for 2008 indicate that dry deposition of nitrogen, so far based on detailed monitoring of ambient NOx levels, is underestimated substantially. The dry deposition of N/NOx in 2008 reported by Ostatnická (2009) was about 0.5 g.m-2.year-1 over 99.5 % of the nation-wide area, while the contribution of unmeasured nitrogen species estimated by CAMx model were much higher. To be specific, the dry deposition of N/HNO3(g) accounted for 1.0 g.m-2.year-1, and N/NH3 for 1.6 g.m-2.year-1. In contrast, the deposition of N/HONO (g) with 0.001 g.m-2.year-1, N/PAN with 0.007 g.m-2.year-1, particulate N/NO3- with 0.002 g.m-2.year-1, and particulate N/NH4

  19. The Measurement of Dry Deposition and Surface Runoff to Quantify Urban Road Pollution in Taipei, Taiwan

    Directory of Open Access Journals (Sweden)

    Jen-Yang Lin

    2013-10-01

    Full Text Available Pollutants deposited on road surfaces and distributed in the environment are a source of nonpoint pollution. Field data are traditionally hard to collect from roads because of constant traffic. In this study, in cooperation with the traffic administration, the dry deposition on and road runoff from urban roads was measured in Taipei City and New Taipei City, Taiwan. The results showed that the dry deposition is 2.01–5.14 g/m2·day and 78–87% of these solids are in the 75–300 µm size range. The heavy metals in the dry deposited particles are mainly Fe, Zn, and Na, with average concentrations of 34,978, 1,519 and 1,502 ppm, respectively. Elevated express roads show the highest heavy metal concentrations. Not only the number of vehicles, but also the speed of the traffic should be considered as factors that influence road pollution, as high speeds may accelerate vehicle wear and deposit more heavy metals on road surfaces. In addition to dry deposition, the runoff and water quality was analyzed every five minutes during the first two hours of storm events to capture the properties of the first flush road runoff. The sample mean concentration (SMC from three roads demonstrated that the first flush runoff had a high pollution content, notably for suspended solid (SS, chemical oxygen demand (COD, oil and grease, Pb, and Zn. Regular sweeping and onsite water treatment facilities are suggested to minimize the pollution from urban roads.

  20. Source-receptor relationship of wet and dry depositions of PAHs in Northeast Asia

    Science.gov (United States)

    Inomata, Yayoi; Kajino, Mizuo; Sato, Keiichi; Kurokawa, Junichi; Tang, Ning; Ohara, Toshimasa; Hayakawa, Kazuichi; Ueda, Hiromasa

    2016-04-01

    The spatial distribution of polycyclic aromatic hydrocarbons (PAHs) deposition by the source-receptor analysis over Northeast Asia was investigated by using an Eulerian regional-scale aerosol chemical model denoted as Regional Air Quality Model 2 for Persistent Organic Pollutants (RAQM2-POP version) at the year of 2005. We confirmed that the simulation was reproduced the PAH concentrations in precipitation based on comparison with observed and simulated concentrations. In this research, the domain was divided into six-source regions (Northern China, NCHN; Central China, CCHN; South China, SCHN; eastern Russia, ERUS; South Korea, SKOR; Japan, JPN) and three-receptor regions (Yellow Sea and East China Sea, ECS; the Sea of Japan, SOJ; northwestern Pacific Ocean, NWP). We focus on benzo[a]pyrene (BaP), which is the most carcinogenic species. The largest emission occurs on CCHN, following SCHN, NCHN, ERUS, SKOR, JPN. In the three Chinese domains and ERUS, the largest contribution to the dry and wet deposition is the domestic origin. In these domains, the wet deposition amount of BaP was 2-16 times larger than those of the dry deposition amount. The total deposition (wet+dry) amount was lower than those of the emission amount. In contrast, the total depositions are larger than the emissions from their own domains in the downwind region (SKOR, JPN), indicating a signature of long-range transport of PAH to the downwind regions. The relative contributions from the three Chinese domains and ERUS to the downwind region (KOR, JPN) are evaluated. For wet deposition in winter, the relative contribution from NCHN and CCHN (20-69%) are larger, whereas the relative contribution from CCHN, SCHN, RUS (13-57%) are larger in summer. These are controlled by the distribution of precipitation. For dry deposition, the relative contribution from NCHN and CCHN (28-49%) are large in winter season, whereas the relative contribution from the three Chinese domains and ERUS are decrease in summer

  1. Assessment of dry and wet atmospheric deposits of radioactive aerosols: application to Fukushima radiocaesium fallout.

    Science.gov (United States)

    Gonze, Marc-André; Renaud, Philippe; Korsakissok, Irène; Kato, Hiroaki; Hinton, Thomas G; Mourlon, Christophe; Simon-Cornu, Marie

    2014-10-07

    The Fukushima Dai-ichi nuclear accident led to massive atmospheric deposition of radioactive substances onto the land surfaces. The spatial distribution of deposits has been estimated by Japanese authorities for gamma-emitting radionuclides through either airborne monitoring surveys (since April 2011) or in situ gamma-ray spectrometry of bare soil areas (since summer 2011). We demonstrate that significant differences exist between the two surveys for radiocaesium isotopes and that these differences can be related to dry deposits through the use of physically based relationships involving aerosol deposition velocities. The methodology, which has been applied to cesium-134 and cesium-137 deposits within 80-km of the nuclear site, provides reasonable spatial estimations of dry and wet deposits that are discussed and compared to atmospheric numerical simulations from the Japanese Atomic Energy Agency and the French Institute of Radioprotection and Nuclear Safety. As a complementary approach to numerical simulations, this field-based analysis has the possibility to contribute information that can be applied to the understanding and assessment of dose impacts to human populations and the environment around Fukushima.

  2. Investigating sources of gaseous oxidized mercury in dry deposition at three sites across Florida, USA

    Directory of Open Access Journals (Sweden)

    M. Sexauer Gustin

    2012-07-01

    Full Text Available During 2009–2010, the State of Florida established a series of air quality monitoring stations to collect data for development of a statewide total maximum daily load (TMDL for mercury (Hg. At three of these sites, located near Ft. Lauderdale (DVE, Pensacola (OLF, and Tampa Bay (TPA, passive samplers for the measurement of air Hg concentrations and surrogate surfaces for measurement of Hg dry deposition were deployed. While it is known that Hg in wet deposition in Florida is high compared to the rest of the United States, there is little information on Hg dry deposition. The objectives of the work were to: (1 investigate the utility of passive sampling systems for Hg in an area with low and consistent air concentrations as measured by the Tekran® mercury measurement system, (2 estimate dry deposition of gaseous oxidized Hg, and (3 investigate potential sources. This paper focuses on Objective 3. All sites were situated within 15 km of 1000 MW electricity generating plants (EGPs and major highways. Bi-weekly dry deposition and passive sampler Hg uptake were not directly correlated with the automated Tekran® system measurements, and there was limited agreement between these systems for periods of high deposition. Using diel, biweekly, and seasonal Hg observations, and ancillary data collected at each site, the potential sources of Hg deposited to surrogate surfaces were investigated. With this information, we conclude that there are three major processes/sources contributing to Hg dry deposition in Florida, with these varying as a function of location and time of year. These include: (1 in situ oxidation of locally and regionally derived Hg facilitated by mobile source emissions, (2 indirect and direct inputs of Hg from local EGPs, and (3 direct input of Hg associated with long range transport of air from the Northeastern United States. We also suggest based on the data collected with the Tekran® and passive sampling systems that different

  3. Enhanced dry deposition of nitrogen pollution near coastlines: A case study covering the Chesapeake Bay estuary and Atlantic Ocean coastline

    Science.gov (United States)

    Loughner, Christopher P.; Tzortziou, Maria; Shroder, Shulamit; Pickering, Kenneth E.

    2016-12-01

    Atmospheric deposition of nitrogen pollution is one of the major sources of nitrogen to many terrestrial and aquatic ecosystems, worldwide. This modeling study suggests that coastlines frequently experience disproportionally high dry deposition of reactive nitrogen. High concentrations of air pollution from coastal cities often accumulate over adjacent estuaries and coastal waters due to low dry deposition rates over the water and a shallow marine boundary layer trapping marine emissions. As high concentrations of pollutants over the water are transported inland, enhanced dry deposition occurs onshore along the coastlines. Large spatial gradients in air pollutants and deposition totals are simulated along the coastline with decreasing concentrations/deposition as the distance from the water increases. As pollutants are transported onshore, air pollution mixing ratios near the surface decrease due to removal by dry deposition, vertical dilution due to deeper mixing layer heights, and decrease in friction velocity as a function of distance inland from the coastline. Ammonium nitrate formation near agricultural ammonia sources, sodium nitrate formation near coastal areas with atmospheric sea-salt loadings, and particulate growth via water uptake also contribute to large nitrate dry deposition totals at the coastline. Gradients in dry N deposition are evident over a monthly time scale and are enhanced during sea and bay breeze events. Current existing N-deposition monitoring networks do not capture the large spatial gradients of ammonium, nitrate, and nitric acid concentrations near coastlines predicted by the model due to the coarse spatial density distribution of monitoring sites.

  4. Wet and dry atmospheric depositions of inorganic nitrogen during plant growing season in the coastal zone of Yellow River Delta.

    Science.gov (United States)

    Yu, Junbao; Ning, Kai; Li, Yunzhao; Du, Siyao; Han, Guangxuan; Xing, Qinghui; Wu, Huifeng; Wang, Guangmei; Gao, Yongjun

    2014-01-01

    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 SO4 (2-) 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.

  5. The sources of trace element pollution of dry depositions nearby a drinking water source.

    Science.gov (United States)

    Guo, Xinyue; Ji, Hongbing; Li, Cai; Gao, Yang; Ding, Huaijian; Tang, Lei; Feng, Jinguo

    2017-02-01

    Miyun Reservoir is one of the most important drinking water sources for Beijing. Thirteen atmospheric PM sampling sites were established around this reservoir to analyze the mineral composition, morphological characteristics, element concentration, and sources of atmospheric PM pollution, using transmission electron microscope, X-ray diffraction, and inductively coupled plasma mass spectrometry analyses. The average monthly dry deposition flux of aerosols was 15.18 g/m(2), with a range of 5.78-47.56 g/m(2). The maximum flux season was winter, followed by summer, autumn, and spring. Zn and Pb pollution in this area was serious, and some of the sample sites had Cr, Co, Ni, and Cu pollution. Deposition fluxes of Zn/Pb in winter and summer reached 99.77/143.63 and 17.04/33.23 g/(hm(2) month), respectively. Principal component analysis showed two main components in the dry deposition; the first was Cr, Co, Ni, Cu, and Zn, and the other was Pb and Cd. Principal sources of the trace elements were iron mining and other anthropogenic activities in the surrounding areas and mountainous area north of the reservoir. Mineralogy analysis and microscopic conformation results showed many iron minerals and some unweathered minerals in dry deposition and atmospheric particulate matter, which came from an iron ore yard in the northern mountainous area of Miyun County. There was possible iron-rich dry deposition into Miyun Reservoir, affecting its water quality and harming the health of people living in areas around the reservoir and Beijing.

  6. Evaluating the relationship between wildfire extent and nitrogen dry deposition in a boreal forest in interior Alaska

    Science.gov (United States)

    Nagano, Hirohiko; Iwata, Hiroki

    2017-03-01

    Alaska wildfires may play an important role in nitrogen (N) dry deposition in Alaskan boreal forests. Here we used annual N dry deposition data measured by CASTNET at Denali National Park (DEN417) during 1999-2013, to evaluate the relationships between wildfire extent and N dry deposition in Alaska. We established six potential factors for multiple regression analysis, including burned area within 100 km of DEN417 (BA100km) and in other distant parts of Alaska (BAAK), the sum of indexes of North Atlantic Oscillation and Arctic Oscillation (OI), number of days with negative OI (OIday), precipitation (PRCP), and number of days with PRCP (PRCPday). Multiple regression analysis was conducted for both time scales, annual (using only annual values of factors) and six-month (using annual values of BAAK and BA100km, and fire and non-fire seasons' values of other four factors) time scales. Together, BAAK, BA100km, and OIday, along with PRCPday in the case of the six-month scale, explained more than 92% of the interannual variation in N dry deposition. The influence of BA100km on N dry deposition was ten-fold greater than from BAAK; the qualitative contribution was almost zero, however, due to the small BA100km. BAAK was the leading explanatory factor, with a 15 ± 14% contribution. We further calculated N dry deposition during 1950-2013 using the obtained regression equation and long-term records for the factors. The N dry deposition calculated for 1950-2013 revealed that an increased occurrence of wildfires during the 2000s led to the maximum N dry deposition exhibited during this decade. As a result, the effect of BAAK on N dry deposition remains sufficiently large, even when large possible uncertainties (>40%) in the measurement of N dry deposition are taken into account for the multiple regression analysis.

  7. Erosion and deposition in depth-averaged models of dense, dry, inclined, granular flows

    Science.gov (United States)

    Jenkins, James T.; Berzi, Diego

    2016-11-01

    We derive expressions for the rates of erosion and deposition at the interface between a dense, dry, inclined granular flow and an erodible bed. In obtaining these, we assume that the interface between the flowing grains and the bed moves with the speed of a pressure wave in the flow, for deposition, or with the speed of a disturbance through the contacting particles in the bed, for erosion. We employ the expressions for the rates of erosion and deposition to show that after an abrupt change in the angle of inclination of the bed the characteristic time for the motion of the interface is much shorter than the characteristic time of the flow. This eliminates the need for introducing models of erosion and deposition rate in the mass balance; and the instantaneous value of the particle flux is the same function of the instantaneous value of the flow depth as in a steady, uniform flow.

  8. Measurements of ammonia concentrations, fluxes and dry deposition velocities to a spruce forest 1991-1995

    DEFF Research Database (Denmark)

    Andersen, H.V.; Hovmand, M.F.; Hummelshøj, P.;

    1999-01-01

    at conditions with easterly winds, the air have passed central Jutland with large emission areas. Some of the relatively low deposition velocities or emissions were observed during conditions with low ammonia concentration and westerly winds. These observations might relate to a compensation point of the forest...... measuring period characterized by easterly winds with dry conditions and high ammonia concentrations, and the emissions might relate to evaporation from ammonia saturated surfaces or emission from mineralization in the forest soil. In general, relatively high net deposition velocities were observed during...

  9. Pharmaceutical aerosols deposition patterns from a Dry Powder Inhaler: Euler Lagrangian prediction and validation.

    Science.gov (United States)

    Ravi Kannan, Ravishekar; Przekwas, A J; Singh, Narender; Delvadia, Renishkumar; Tian, Geng; Walenga, Ross

    2017-04-01

    This study uses Computational Fluid Dynamics (CFD) to predict, analyze and validate the deposition patterns in a human lung for a Budesonide drug delivered from the Novolizer Dry Powder Inhaler device. We used a test case of known deposition patterns to validate our computational Euler Lagrangian-based deposition predictions. Two different lung models are used: (i) a basic ring-less trachea model and (ii) an advanced Human Zygote5 model. Unlike earlier attempts, the current simulations do not include the device in the computational domain. This greatly reduces the computational effort. To mimic the device, we model the inlet particle jet stream from the device as a spray entering the mouth in a conical fashion. Deposition studies in the various lung regions were performed. We were able to computationally predict and then demonstrate the enhanced deposition in the tracheal and first generation rings/ridges. The enhanced vorticity creation due to the ring structure and the geometrical design contributes to larger deposition in the Zygote5 model. These are in accord with existing data, unlike the ring-less model. Our validated results indicate the need to (i) introduce the ridges in the experimental casts and the CFD surface meshes to be anatomically consistent and obtain physiologically consistent depositions; (ii) introduce a factor to account for the recirculating lighter particles in empirical models.

  10. Lung deposition of salbutamol in healthy human subjects from the MAGhaler dry powder inhaler.

    Science.gov (United States)

    Newman, S; Malik, S; Hirst, R; Pitcairn, G; Heide, A; Pabst, J; Dinkelaker, A; Fleischer, W

    2002-12-01

    The MAGhaler (Mundipharma GmbH) is a multidose dry powder inhaler (DPI) containing a novel formulation of drug and lactose compacted by an isostatic pressing technique (GGU GmbH). On actuation, a precise dose is metered from a compacted ring-shaped drug tablet. In this study, the lung deposition of salbutamol from this device has been assessed. Ten healthy non-smoking subjects completed a two-way cross-over study assessing the pulmonary deposition of salbutamol (200 microg) from the MAGhaler at high (60 l/min) and low (30 l/min) peak inhaled flow rates (PIFRs), representing maximal and sub-maximal inspiratory efforts. The formulation was radiolabelled with 99mTc, and lung and oropharyngeal depositions were quantified by gamma scintigraphyThe mean (SD)% ofthe delivered dose deposited in the lungs was 26.4 (4.3)% at 60 l/min and 21.1 (5.1)% at 30 l/min (P < 0.05), corresponding to mean lung depositions of 52.8 and 42.2 microg salbutamol, respectively. The distribution of drug within different lung regions did not vary significantly with inhaled flow rate. The data provided proof of concept for the novel inhaler device and the innovative drug formulation. In comparison with previous deposition data obtained with other DPIs, the lung deposition was relatively high, relatively reproducible (coefficient of variation 16% at 60 l/min) and relatively insensitive to the change in peak inhaled flow rate.

  11. Atmospheric dry deposition of trace elements measured around the urban and industrially impacted NY-NJ harbor

    Science.gov (United States)

    Yi, Seung-Muk; Totten, Lisa A.; Thota, Sathyapriya; Yan, Shu; Offenberg, John H.; Eisenreich, Steven J.; Graney, Joseph; Holsen, Thomas M.

    Long-term direct trace metal dry deposition measurements were made during 2001 and 2002 at two sites near the NY/NJ Harbor Estuary in New Jersey: Jersey City (JC) and New Brunswick (NB). In addition intensive dry deposition and atmospheric size distribution (ASD) measurements were made between September 2001 and June 2002. Dry deposition samples were obtained using modified MIC-B wet deposition samplers which deployed knife-edge surrogate surfaces during dry periods. ASDs were measured with micro-orifice uniform deposit impactors (MOUDI) and coarse particle rotary impactors (CPRI). The fluxes of trace metals were found to be highest at the JC site and lowest at the NB site. The dry deposition fluxes ranged from 0.030 (Cd) to 3800 (Al) μg m -2 d -1 and 0.14 (Cd) to 8100 (Al) μg m -2 d -1at NB and JC sites, respectively. Metals of crustal origin were found mostly in the coarse particle fraction and anthropogenic metals were found mostly in the fine particle fraction. For the intensive experiments, overall dry deposition velocities of several trace metals were determined by dividing measured fluxes by measured concentrations in different particle size ranges. For most of the elements, the flux was highly correlated with PM 10 and coarse particle concentrations. The overall dry deposition velocities of crustal elements (Al and Mg) varied from 3.7 to 8.7 cm s -1 with correlation coefficients ranging from 0.50 to 0.84. The best-fit dry deposition velocities for anthropogenic elements (Cr, Mn, Zn, and Pb; Cu, Mo, and Ba; V and Ni) varied more than those for crustal elements (0.52-25 vs. 3.7-8.7 cm s -1). The dry deposition velocities for most elements obtained using three size ranges were statistically significant with R2 values ranging from 0.37 to 0.84 except for V and Ni (0.12).

  12. Influence of agricultural biomass burning on aerosol size distribution and dry deposition in southeastern Brazil.

    Science.gov (United States)

    Rocha, Gisele O; Allen, Andrew G; Cardoso, Arnaldo A

    2005-07-15

    The size distributed composition of ambient aerosols is used to explore seasonal differences in particle chemistry and to show that dry deposition fluxes of soluble species, including important plant nutrients, increase during periods of biomass (sugar cane trash) burning in São Paulo State, Brazil. Measurements were made at a single site centrally located in the State's sugar cane growing region but away from the immediate vicinity of burns, so that the airsampled was representative of the regional background. Calculation of ion equivalent balances showed that during burning periods smaller particles (Aitken and accumulation modes) were more acidic, containing higher concentrations of SO4(2-), oxalate, NO3-, HCOO-, CH3COO-, and CI-, but insufficient NH4+ and K+ to achieve neutrality. Larger particles showed an anion deficit due to the presence of unmeasured ions and comprised resuspended dusts modified by accumulation of nitrate, chloride, and organic anions. Increases of resuspended particles during the burning season were attributed to release of earlier deposits from the surfaces of burning vegetation as well as increased vehicle movement on unsurfaced roads. During winter months the relative contribution of combined emissions from road transport and industry diminished due to increased emissions from biomass combustion and other activities specifically associated with the harvest period. Positive increments in annual particulate dry deposition fluxes due to higher fluxes during the sugar cane harvest were 44.3% (NH4+), 42.1% (K+), 31.8% (Mg2+), 30.4% (HCOO-), 12.8% (CI-), 6.6% (CH3COO-), 5.2% (Ca2+), 3.8% (SO4(2-)), and 2.3% (NO3-). Na+ and oxalate fluxes were seasonally invariant. Annual aerosol dry deposition fluxes (kg ha(-1)) were 0.5 (Na+), 0.25 (NH4+), 0.39 (K+), 0.51 (Mg2+), 3.19 (Ca2+), 1.34 (Cl-), 4.47 (NO3-), 3.59 (SO4(2-)), 0.58 (oxalate), 0.71 (HCOO-), and 1.38 (CH3COO-). Contributions of this mechanism to combined aerosol dry deposition and

  13. Drying, phase separation, and deposition in droplets of sunset yellow chromonic liquid crystal

    Science.gov (United States)

    Gross, Adam; Davidson, Zoey S.; Huang, Yongyang; Still, Tim; Zhou, Chao; Yodh, A. G.

    We investigate the drying process and the final deposition patterns of multi-phase sessile droplets containing aqueous lyotropic chromonic liquid crystal (LC). The experiments employ a variety of optical techniques including profilometry, polarization optical microscopy and optical coherence microscopy. An unusual hierarchical LC assembly is observed during drying; in particular, LC mesogens are first formed at the start of drying and then compartments of isotropic, nematic and columnar phases arise. Nonuniform evaporation creates concentration gradients in droplets such that LC phases emerge from the outer edge of the drop and advance to the center over the course of drying. Distinct outward flows associated with the ``coffee-ring effect'' are seen initially, but the assembly of the mesogens creates viscosity, density, and surface tension gradients that effectively introduce new convective flows and complex LC phase boundaries within the drop. Finally, we show that the final deposit shape of chromonic materials changes with rate of evaporation. We gratefully acknowledge financial support through NSF DMR12-05463, MRSEC DMR11-20901, NASA NNX08AO0G, and NSF DBI-1455613.

  14. Observation- and model-based estimates of particulate dry nitrogen deposition to the oceans

    Directory of Open Access Journals (Sweden)

    A. R. Baker

    2017-07-01

    Full Text Available Anthropogenic nitrogen (N emissions to the atmosphere have increased significantly the deposition of nitrate (NO3− and ammonium (NH4+ to the surface waters of the open ocean, with potential impacts on marine productivity and the global carbon cycle. Global-scale understanding of the impacts of N deposition to the oceans is reliant on our ability to produce and validate models of nitrogen emission, atmospheric chemistry, transport and deposition. In this work,  ∼  2900 observations of aerosol NO3− and NH4+ concentrations, acquired from sampling aboard ships in the period 1995–2012, are used to assess the performance of modelled N concentration and deposition fields over the remote ocean. Three ocean regions (the eastern tropical North Atlantic, the northern Indian Ocean and northwest Pacific were selected, in which the density and distribution of observational data were considered sufficient to provide effective comparison to model products. All of these study regions are affected by transport and deposition of mineral dust, which alters the deposition of N, due to uptake of nitrogen oxides (NOx on mineral surfaces. Assessment of the impacts of atmospheric N deposition on the ocean requires atmospheric chemical transport models to report deposition fluxes; however, these fluxes cannot be measured over the ocean. Modelling studies such as the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP, which only report deposition flux, are therefore very difficult to validate for dry deposition. Here, the available observational data were averaged over a 5° × 5° grid and compared to ACCMIP dry deposition fluxes (ModDep of oxidised N (NOy and reduced N (NHx and to the following parameters from the Tracer Model 4 of the Environmental Chemical Processes Laboratory (TM4: ModDep for NOy, NHx and particulate NO3− and NH4+, and surface-level particulate NO3− and NH4+ concentrations. As a model ensemble, ACCMIP can be

  15. Combined effects of iron and copper from atmospheric dry deposition on ocean productivity

    Science.gov (United States)

    Wang, F. J.; Chen, Y.; Guo, Z. G.; Gao, H. W.; Mackey, K. R.; Yao, X. H.; Zhuang, G. S.; Paytan, A.

    2017-03-01

    Atmospheric deposition can provide nutrients and potential toxicants to marine ecosystem, hence affecting ocean net primary productivity (NPP). Nonetheless, the interactive effects of mixed aerosol components on phytoplankton have rarely been reported. Here we explored the combined effects of iron (Fe) and copper (Cu) on NPP over the East China Sea. In aerosol addition mesocosm experiments, phytoplankton growth was suppressed under high aerosol Cu but was increased when high Cu was accompanied by high Fe in aerosols. A time series of soluble aerosol Fe and Cu deposition was obtained and compared to regional chlorophyll a (Chl a) abundances from Moderate Resolution Imaging Spectroradiometer/Aqua. Strong positive correlations were observed between the dry flux ratios of soluble Fe/Cu and Chl a abundances in the large offshore area, whereas these variables were uncoupled in coastal regions where riverine input and upwelling dominated the biogeochemistry. Current work provides insight into the complex linkage between atmospheric deposition and marine productivity.

  16. Aerosol dry deposition on vegetative canopies. Part II: A new modelling approach and applications

    Science.gov (United States)

    Petroff, Alexandre; Mailliat, Alain; Amielh, Muriel; Anselmet, Fabien

    2008-05-01

    This paper presents a new approach for the modelling of aerosol dry deposition on vegetation. It follows a companion article, in which a review of the current knowledge highlights the need for a better description of the aerosol behaviour within the canopy [Petroff, A., Mailliat, A., Amielh, M., Anselmet, F., 2008. Aerosol dry deposition on vegetative canopies. Part I: Review of present knowledge. Atmospheric Environment, in press, doi:10.1016/j.atmosenv.2007.09.043]. Concepts from multi-phase flow studies are used for describing the canopy medium and deriving a time and space-averaged aerosol balance equation and the associated deposition terms. The closure of the deposition terms follows an up-scaling procedure based on the statistical distribution of the collecting elements. This aerosol transport model is then applied in a stationary and mono-dimensional configuration and takes into account the properties of the vegetation, the aerosol and the turbulent flow. Deposition mechanisms are Brownian diffusion, interception, inertial and turbulent impactions, and gravitational settling. For each of them, a parameterisation of the particle collection is derived and the quality of their predictions is assessed by comparison with wind-tunnel deposition measurements on coniferous twigs [Belot, Y., Gauthier, D., 1975. Transport of micronic particles from atmosphere to foliar surfaces. In: De Vries, D.A., Afgan, N.H. (Eds.), Heat and Mass Transfer in the Biosphere. Scripta Book, Washington, DC, pp. 583-591; Belot, Y., 1977. Etude de la captation des polluants atmosphériques par les végétaux. CEA, R-4786, Fontenay-aux-Roses; Belot, Y., Camus, H., Gauthier, D., Caput, C., 1994. Uptake of small particles by canopies. The Science of the Total Environment 157, 1-6]. Under a real canopy configuration, the predictions of the aerosol transport model compare reasonably well with detailed on-site deposition measurements of Aitken mode particles [Buzorius, G., Rannik, Ü., M

  17. Impact of future land cover changes on HNO3 and O3 surface dry deposition

    Directory of Open Access Journals (Sweden)

    T. Verbeke

    2015-07-01

    Full Text Available Dry deposition is a key component of surface–atmosphere exchange of compounds, acting as a sink for several chemical species. Meteorological factors, chemical properties of the trace gas considered and land surface properties are strong drivers of dry deposition efficiency and variability. Under both climatic and anthropogenic pressure, the vegetation distribution over the Earth has been changing a lot over the past centuries, and could be significantly altered in the future. In this study, we perform a modeling investigation of the potential impact of land-cover changes between present-day (2006 and the future (2050 on dry deposition rates, with special interest for ozone (O3 and nitric acid vapor (HNO3, two compounds which are characterized by very different physico-chemical properties. The 3-D chemistry transport model LMDz-INCA is used, considering changes in vegetation distribution based on the three future projections RCPs 2.6, 4.5 and 8.5. The 2050 RCP 8.5 vegetation distribution leads to a rise up to 7 % (+0.02 cm s−1 in VdO3 and a decrease of −0.06 cm s−1 in VdHNO3 relative to the present day values in tropical Africa, and up to +18 and −15 % respectively in Australia. When taking into account the RCP 4.5 scenario, which shows dramatic land cover change in Eurasia, VdHNO3 increases by up to 20 % (annual-mean value and reduces VdO3 by the same magnitude in this region. When analyzing the impact of dry deposition change on atmospheric chemical composition, our model calculates that the effect is lower than 1 ppb on annual mean surface ozone concentration, for both for the RCP8.5 and RCP2.6 scenarios. The impact on HNO3 surface concentrations is more disparate between the two scenarios, regarding the spatial repartition of effects. In the case of the RCP 4.5 scenario, a significant increase of the surface O3 concentration reaching locally up to 5 ppb (+5 % is calculated on average during the June–August period. This scenario

  18. Characteristics Of Atmospheric Dry Deposition Of Metals To The Region Of Lake Asan And Sapgyo, Korea

    Science.gov (United States)

    Han, J.; Shin, H.; Lee, M.; Lim, Y.; Seo, M.; Jung, I.

    2008-12-01

    Environment includes a multi-media such as air, surface water, soil, underground water and ecosystem. Some pollutants transfer among a multi-media, posing serious threat to humans, animals and plants. Pollutants released into the environment remain for long times and transport long distances while going through physical and chemical interactions such as transports between multi-media ; air, water and soil, deposition, and absorption and release from organisms. This study assessed the amount of heavy metals transferred from air to water and soil using dry deposition plate and water surface sampler during spring (June 13 ~ 21, 2007) and winter (October 23 ~ 30 in 2007) at 9 locations including Dangjin, Pyeongtaek and Asan. Micro-Orifice Uniform Deposit Impactor, MOUDI was used to confirm the size distribution. The measured heavy metal deposition flux was compared with the expectation obtained with deposition model. In addition, amount of heavy metal deposition at Asan and Sapgyo lakes were evaluated to verify the water pollution state driven by atmospheric deposition. Atmospheric dry deposition flux of metals are 133.92 microgram m-2 day-1, 44.01 microgram m-2 day-1, 0.915 microgram m-2 day-1, and 0.175 microgram m-2 day-1 during spring, and 72.86 microgram m-2 day- 1, 88.14 microgram m-2 day-1, 0.991 microgram m-2 day-1, and 0.189 microgram m-2 day-1 during fall, for lead, nickel, arsenic, and cadmium, respectively. It is required to re- calculation the dry deposition flux by land use type due to possibility of underestimating the flux in case of using grease surrogate surface having low surface roughness. The cadmium, lead, and arsenic size distribution was mono-modal with the peaks in the 0.65 ~ 1.1 micrometer size range in the fine mode showing sharp peak in the condensation submode especially for cadmium and lead because of effect of primary emission. The nickel size distribution was bimodal, a typical size distribution for an urban atmosphere, showing sharp

  19. Dry deposition of gaseous radioiodine and particulate radiocaesium onto leafy vegetables

    Energy Technology Data Exchange (ETDEWEB)

    Tschiersch, Jochen, E-mail: tschiersch@helmholtz-muenchen.de [Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Institute of Radiation Protection, Ingolstaedter Landstr. 1, 85764 Neuherberg (Germany); Shinonaga, Taeko [Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Institute of Radiation Protection, Ingolstaedter Landstr. 1, 85764 Neuherberg (Germany); Heuberger, Heidi [TU Muenchen, Center of Life and Food Sciences Weihenstephan, Duernast 2, 85350 Freising (Germany)

    2009-10-15

    Radionuclides released to the atmosphere during dry weather (e.g. after a nuclear accident) may contaminate vegetable foods and cause exposure to humans via the food chain. To obtain experimental data for an appropriate assessment of this exposure path, dry deposition of radionuclides to leafy vegetables was studied under homogeneous and controlled greenhouse conditions. Gaseous {sup 131}I-tracer in predominant elemental form and particulate {sup 134}Cs-tracer at about 1 {mu}m diameter were used to identify susceptible vegetable species with regard to contamination by these radionuclides. The persistence was examined by washing the harvested product with water. The vegetables tested were spinach (Spinacia oleracea), butterhead lettuce (Lactuca sativa var. capitata), endive (Cichorium endivia), leaf lettuce (Lactuca sativa var. crispa), curly kale (Brassica oleracea convar. acephala) and white cabbage (Brassica oleracea convar. capitata). The variation of radionuclides deposited onto each vegetable was evaluated statistically using the non-parametric Kruskal-Wallis Test and the U-test of Mann-Whitney. Significant differences in deposited {sup 131}I and {sup 134}Cs activity concentration were found among the vegetable species. For {sup 131}I, the deposition velocity to spinach normalized to the biomass of the vegetation was 0.5-0.9 cm{sup 3} g{sup -1} s{sup -1} which was the highest among all species. The particulate {sup 134}Cs deposition velocity of 0.09 cm{sup 3} g{sup -1} s{sup -1} was the highest for curly kale, which has rough and structured leaves. The lowest deposition velocity was onto white cabbage: 0.02 cm{sup 3} g{sup -1} s{sup -1} (iodine) and 0.003 cm{sup 3} g{sup -1} s{sup -1} (caesium). For all species, the gaseous iodine deposition was significantly higher compared to the particulate caesium deposition. The deposition depends on the sensitive parameters leaf area, stomatal aperture, and plant morphology. Decontamination by washing with water was very

  20. A corrected formulation of the Multilayer Model (MLM) for inferring gaseous dry deposition to vegetated surfaces

    Science.gov (United States)

    Saylor, Rick D.; Wolfe, Glenn M.; Meyers, Tilden P.; Hicks, Bruce B.

    2014-08-01

    The Multilayer Model (MLM) has been used for many years to infer dry deposition fluxes from measured trace species concentrations and standard meteorological measurements for national networks in the U.S., including the U.S. Environmental Protection Agency's Clean Air Status and Trends Network (CASTNet). MLM utilizes a resistance analogy to calculate deposition velocities appropriate for whole vegetative canopies, while employing a multilayer integration to account for vertically varying meteorology, canopy morphology and radiative transfer within the canopy. However, the MLM formulation, as it was originally presented and as it has been subsequently employed, contains a non-physical representation related to the leaf-level quasi-laminar boundary layer resistance that affects the calculation of the total canopy resistance. In this note, the non-physical representation of the canopy resistance as originally formulated in MLM is discussed and a revised, physically consistent, formulation is suggested as a replacement. The revised canopy resistance formulation reduces estimates of HNO3 deposition velocities by as much as 38% during mid-day as compared to values generated by the original formulation. Inferred deposition velocities for SO2 and O3 are not significantly altered by the change in formulation (<3%). Inferred deposition loadings of oxidized and total nitrogen from CASTNet data may be reduced by 10-20% and 5-10%, respectively, for the Eastern U. S. when employing the revised formulation of MLM as compared to the original formulation.

  1. A Corrected Formulation of the Multilayer Model (MLM) for Inferring Gaseous Dry Deposition to Vegetated Surfaces

    Science.gov (United States)

    Saylor, Rick D.; Wolfe, Glenn M.; Meyers, Tilden P.; Hicks, Bruce B.

    2014-01-01

    The Multilayer Model (MLM) has been used for many years to infer dry deposition fluxes from measured trace species concentrations and standard meteorological measurements for national networks in the U.S., including the U.S. Environmental Protection Agency's Clean Air Status and Trends Network (CASTNet). MLM utilizes a resistance analogy to calculate deposition velocities appropriate for whole vegetative canopies, while employing a multilayer integration to account for vertically varying meteorology, canopy morphology and radiative transfer within the canopy. However, the MLM formulation, as it was originally presented and as it has been subsequently employed, contains a non-physical representation related to the leaf-level quasi-laminar boundary layer resistance that affects the calculation of the total canopy resistance. In this note, the non-physical representation of the canopy resistance as originally formulated in MLM is discussed and a revised, physically consistent, formulation is suggested as a replacement. The revised canopy resistance formulation reduces estimates of HNO3 deposition velocities by as much as 38% during mid-day as compared to values generated by the original formulation. Inferred deposition velocities for SO2 and O3 are not significantly altered by the change in formulation (less than 3%). Inferred deposition loadings of oxidized and total nitrogen from CASTNet data may be reduced by 10-20% and 5-10%, respectively, for the Eastern U. S. when employing the revised formulation of MLM as compared to the original formulation.

  2. Dry deposition profile of small particles within a model spruce canopy

    Energy Technology Data Exchange (ETDEWEB)

    Ould-Dada, Zitouni [Centre for Analytical Research in the Environment, (now EAS T.H. Huxley School), Imperial College of Science Technology and Medicine, Silwood Park, Ascot, SL57TE Berkshire (United Kingdom)

    2002-03-08

    Data on dry deposition of 0.82 {mu}m MMAD uranium particles to a small scale, 'model' Norway spruce (Picea abies) canopy have been determined by means of wind tunnel experiments. These are presented for both the total canopy and for five horizontal layers within the canopy. The results show a complex pattern of deposition within the canopy. The highest deposition velocity V{sub g} (0.19 cm s{sup -1}) was recorded for the topmost layer within the canopy (i.e. the layer in direct contact with the boundary layer) whereas the lowest V{sub g} (0.02 cm s{sup -1}) occurred at the soil surface. Vertical penetration of depositing aerosol through the canopy was influenced by variations in biomass, wind velocity and turbulence within the canopy. A total canopy V{sub g} of 0.5 cm s{sup -1} was obtained and this is in line with field measurements of V{sub g} reported in literature for both anthropogenic and radionuclide aerosols of similar size ranges. Extrapolation of wind tunnel data to 'real' forest canopies is discussed. The information presented here is of importance in predicting the likely contribution of dry deposition of aerosols to pollutant inputs to forest ecosystems, particularly in the context of radioactive aerosol releases from nuclear installations. The application of the present data may also be appropriate for other pollutant aerosols such as SO{sub 4}, NO{sub 3} and NH{sub 4}, which are characterised by particle sizes in the range used in this study.

  3. Emission characters of particulate concentrations and dry deposition studies for incense burning at a Taiwanese temple.

    Science.gov (United States)

    Fang, Guor-Cheng; Chu, Chia-Chium; Wu, Yuh-Shen; Fu, Peter Pi-Cheng

    2002-05-01

    Suspended particulate concentrations were measured at the Tzu Yun Yen temple in the Taichung region of Taiwan. The temple performs traditional incense burning. A universal sampler and a micro-orifice uniform deposited impactor (MOUDI) sampler with a dry deposition plate were used to measure the particulate concentrations. The results show that the average PM2.5/PM10 ratio was 74% during the incense burning period at this temple. In addition, the average suspended particulate (PM10) element concentration of anthropogenic element Zn (495 ng/m3) was higher than the other anthropogenic elements (Pb, Mn, Ni, and Cd). Furthermore, the average mass size distribution was bimodal with major peaks occurring at 0.32-0.56 microm and 5.6-10 microm during the incense burning period. The dry deposition velocities of Cd used fine particulates (PM2.5) and suspended particulate (PM10) mode were 1.86 and 0.99 cm/s in this study, respectively.

  4. Homogeneous matrix deposition on dried agar for MALDI imaging mass spectrometry of microbial cultures.

    Science.gov (United States)

    Hoffmann, Thomas; Dorrestein, Pieter C

    2015-11-01

    Matrix deposition on agar-based microbial colonies for MALDI imaging mass spectrometry is often complicated by the complex media on which microbes are grown. This Application Note demonstrates how consecutive short spray pulses of a matrix solution can form an evenly closed matrix layer on dried agar. Compared with sieving dry matrix onto wet agar, this method supports analyte cocrystallization, which results in significantly more signals, higher signal-to-noise ratios, and improved ionization efficiency. The even matrix layer improves spot-to-spot precision of measured m/z values when using TOF mass spectrometers. With this technique, we established reproducible imaging mass spectrometry of myxobacterial cultures on nutrient-rich cultivation media, which was not possible with the sieving technique. Graphical Abstract ᅟ.

  5. Homogeneous Matrix Deposition on Dried Agar for MALDI Imaging Mass Spectrometry of Microbial Cultures

    Science.gov (United States)

    Hoffmann, Thomas; Dorrestein, Pieter C.

    2015-11-01

    Matrix deposition on agar-based microbial colonies for MALDI imaging mass spectrometry is often complicated by the complex media on which microbes are grown. This Application Note demonstrates how consecutive short spray pulses of a matrix solution can form an evenly closed matrix layer on dried agar. Compared with sieving dry matrix onto wet agar, this method supports analyte cocrystallization, which results in significantly more signals, higher signal-to-noise ratios, and improved ionization efficiency. The even matrix layer improves spot-to-spot precision of measured m/z values when using TOF mass spectrometers. With this technique, we established reproducible imaging mass spectrometry of myxobacterial cultures on nutrient-rich cultivation media, which was not possible with the sieving technique.

  6. Measurements and modeling of emissions, dispersion and dry deposition of ammonia from swine facilities

    Science.gov (United States)

    Bajwa, Kanwardeep Singh

    Ammonia has recently gained importance for its increasing atmospheric concentrations and its role in the formation of aerosols. Studies have shown increasing atmospheric concentration levels of NH3 and NH 4+, especially in the regions of concentrated animal feeding operations. Atmospheric inputs of reduced nitrogen as ammonia and ammonium by dry and wet deposition may represent a substantial contribution to the acidification of semi natural ecosystems and could also affect sensitive coastal ecosystems and estuaries. The anaerobic lagoon and spray method, commonly used for waste storage and disposal in confined animal feeding operations (CAFO), is a significant source of ammonia emissions. An accurate emission model for ammonia from aqueous surfaces can help in the development of emission factors. Study of dispersion and dry deposition patterns of ammonia downwind of a hog farm will help us to understand how much ammonia gets dry deposited near the farm, and how remaining ammonia gets transported farther away. An experimental and modeling study is conducted of emissions, dispersion and dry deposition of ammonia taking one swine farm as a unit. Measurements of ammonia flux were made at 11 swine facilities in North Carolina using dynamic flow-through chamber system over the anaerobic waste treatment lagoons. Continuous measurements of ammonia flux, meteorological and lagoon parameters were made for 8-10 days at each farm during each of the warm and cold seasons. Ammonia concentrations were continuously measured in the chamber placed over the lagoon using a Thermo Environmental Instrument Incorporated (TECO) Model 17c chemiluminescnce ammonia analyzer. A similar ammonia analyzer was used to measure ammonia concentrations at selected locations on the farm. Barn emissions were measured using open-path Fourier transform infrared (OP-FTIR) spectroscopy. A 10 m meteorological tower was erected at each site to measure wind speed and direction, temperature, relative humidity

  7. 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.

  8. Proceedings of the NAPAP (National Acid Precipitation Assessment Program) workshop on dry deposition

    Energy Technology Data Exchange (ETDEWEB)

    Hicks, B.B.; Wesely, M.L.; Lindberg, S.E.; Bromberg, S.M. (eds.)

    1986-01-01

    Knowledge of dry deposition is limited by the inability to make the necessary measurements in other than special circumstances. The need to generate confidence in the available measurement techniques was emphasized. There is need for more frequent collocation of experiments and for more collaboration of researchers. Discussions among the specialist groups focused attention on the greatly dissimilar experimental constraints associated with different techniques. A summary of relevant considerations is given. Extreme difficulties arise when trying to conduct a side-by-side comparison of all of the available methods. In all cases there is need to improve measurement methods. This developmental effort is presently underway, but augmentation is required. The present focus on questions regarding so-called acidic deposition is too confining to permit a broad-based attack on the overall problem of air pollution in the context of energy and agricultural options. A program developed in response to questions concerning acidic deposition should not be expected to address questions arising in other contexts. The acid deposition concern is real and immediate, and if carefully arranged the research program generated to provide the most urgently desired answers could also constitute an entry into a longer-term investigation of broader issues. 34 refs., 3 tabs.

  9. Dry deposition model for a microscale aerosol dispersion solver based on the moment method

    CERN Document Server

    Šíp, Viktor

    2016-01-01

    A dry deposition model suitable for use in the moment method has been developed. Contributions from five main processes driving the deposition - Brownian diffusion, interception, impaction, turbulent impaction, and sedimentation - are included in the model. The deposition model was employed in the moment method solver implemented in the OpenFOAM framework. Applicability of the developed expression and the moment method solver was tested on two example problems of particle dispersion in the presence of a vegetation on small scales: a flow through a tree patch in 2D and a flow through a hedgerow in 3D. Comparison with the sectional method showed that the moment method using the developed deposition model is able to reproduce the shape of the particle size distribution well. The relative difference in terms of the third moment of the distribution was below 10\\% in both tested cases, and decreased away from the vegetation. Main source of this difference is a known overprediction of the impaction efficiency. When ...

  10. An Artificial Turf-Based Surrogate Surface Collector for the Direct Measurement of Atmospheric Mercury Dry Deposition

    Science.gov (United States)

    This paper describes the development of a new artificial turf surrogate surface (ATSS) sampler for use in the measurement of mercury (Hg) dry deposition. In contrast to many existing surrogate surface designs, the ATSS utilizes a three-dimensional deposition surface that may more...

  11. Quantifying particulate matter deposition in Niwot Ridge, Colorado: Collection of dry deposition using marble inserts and particle imaging using the FlowCAM

    Science.gov (United States)

    Goss, Natasha R.; Mladenov, Natalie; Seibold, Christine M.; Chowanski, Kurt; Seitz, Leslie; Wellemeyer, T. Barret; Williams, Mark W.

    2013-12-01

    Atmospheric wet and dry deposition are important sources of carbon for remote alpine lakes and soils. The carbon inputs from dry deposition in alpine National Atmospheric Deposition Program (NADP) collectors, including aeolian dust and biological material, are not well constrained due to difficulties in retaining particulate matter in the collectors. Here, we developed and tested a marble insert for dry deposition collection at the Niwot Ridge Long Term Ecological Research Station (NWT LTER) Soddie site (3345 m) between 24 May and 8 November 2011. We conducted laboratory tests of the insert's effect on particulate matter (PM) mass and non-purgeable organic carbon (DOC) and found that the insert did not significantly change either measurement. Thus, the insert may enable dry deposition collection of PM and DOC at NADP sites. We then developed a method for enumerating the collected wet and dry deposition with the Flow Cytometer and Microscope (FlowCAM), a dynamic-image particle analysis tool. The FlowCAM has the potential to establish morphology, which affects particle settling and retention, through particle diameter and aspect ratio. Particle images were used to track the abundance of pollen grains over time. Qualitative image examination revealed that most particles were biological in nature, such as intact algal cells and pollen. Dry deposition loading to the Soddie site as determined by FlowCAM measurements was highly variable, ranging from 100 to >230 g ha-1 d-1 in June-August 2011 and peaking in late June. No significant difference in diameter or aspect ratio was found between wet and dry deposition, suggesting fundamental similarities between those deposition types. Although FlowCAM statistics and identification of particle types proved insightful, our total-particle enumeration method had a high variance and underestimated the total number of particles when compared to imaging of relatively large volumes (60-125 mL) from a single sample. We recommend use of

  12. Heavy metals determination in dry surrogate depositions, characterization of an urban and a natural site

    Energy Technology Data Exchange (ETDEWEB)

    Barilli, L.; Olivieri, P. [ENEA, Centro Ricerche Ezio Clementel, Bologna (Italy). Dipt. Ambiente; Morselli, L.; Cecchini, M. [Bologna Univ., Bologna (Italy). Dipt. di Chmica Industriale e dei Materiali; Amorolo, R.; Di Carlo, V.; Francacaviglia, R.; Gataleta, L. [Istituto Sperimentale per la Nutrizione delle Piante, Rome (Italy)

    1999-10-01

    The present work describes a methodological approach for the assessment of the amount of several toxic heavy metals (Cd, Cr, Cu, Ni, Pb, Zn) associated with atmospheric particulate matter in surrogate dry deposition. The aim of the study is the evaluation of heavy metal fluxes at ground level in surrogate dry deposition and the comparison between their estimated in two different stations over the period February-December 1997. A description is given of the complete procedure from sampling to data elaboration and results are reported with special attention to the comparative aspects of the two stations. [Italian] Nella presente nota viene descritto un approccio metodologico per la valutazione delle quantita' di alcuni metalli pesanti tossici (Cd, Cr, Cu, Ni, Pb, Zn) associati al particolato atmosferico, nella deposizione secca surrogata a livello del suolo allo scopo di valutare i flussi di metalli pesanti nella deposizione indicata e il confronto tra le due stazioni dal febbraio al dicembre 1997. Viene riportata la descrizione dell'intera procedura, dal campionamento all'elaborazione dei dati, e vengono riportati i risultati.

  13. A modified micrometeorological gradient method for estimating O3 dry deposition over a forest canopy

    Directory of Open Access Journals (Sweden)

    Z. Y. Wu

    2015-01-01

    Full Text Available Small pollutant concentration gradients between levels above a plant canopy result in large uncertainties in estimated air–surface exchange fluxes when using existing micrometeorological gradient methods, including the aerodynamic gradient method (AGM and the modified Bowen-Ratio method (MBR. A modified micrometeorological gradient method (MGM is proposed in this study for estimating O3 dry deposition fluxes over a forest canopy using concentration gradients between a level above and a level below the canopy top, taking advantage of relatively large gradients between these levels due to significant pollutant uptake at top layers of the canopy. The new method is compared with the AGM and MBR methods and is also evaluated using eddy-covariance (EC flux measurements collected at the Harvard Forest Environmental Measurement Site, Massachusetts during 1993–2000. All the three gradient methods (AGM, MBR and MGM produced similar diurnal cycles of O3 dry deposition velocity (Vd(O3 to the EC measurements, with the MGM method being the closest in magnitude to the EC measurements. The multi-year average Vd(O3 differed significantly between these methods, with the AGM, MBR and MGM method being 2.28, 1.45 and 1.18 times of that of the EC. Sensitivity experiments identified several input parameters for the MGM method as first-order parameters that affect the estimated Vd(O3. A 10% uncertainty in the wind speed attenuation coefficient or canopy displacement height can cause about 10% uncertainty in the estimated Vd(O3. An unrealistic leaf area density vertical profile can cause an uncertainty of a factor of 2.0 in the estimated Vd(O3. Other input parameters or formulas for stability functions only caused an uncertainly of a few percent. The new method provides an alternative approach in monitoring/estimating long-term deposition fluxes of similar pollutants over tall canopies.

  14. Atmospheric dry deposition of mineral dust to the Gulf of Aqaba, Red Sea: rate and trace elements.

    Science.gov (United States)

    Al-Taani, Ahmed A; Rashdan, Maen; Khashashneh, Safaa

    2015-03-15

    Atmospheric dry deposition to the Gulf of Aqaba (GoA) is particularly a significant source of trace elements. Amid desert regions, the Gulf receives high fluxes of mineral dust with an average rate of 34.68 g/m(2)/year measured in 2012. Patterns of dry deposition showed seasonal fluxes with highest rates observed in summer and lowest in winter. The observed variations were attributed to wind direction, timing of deposition and sources of dust. The average dry fluxes of Al, Fe, Mn, Cr, Cd, Cu, Pb and Zn were 551, 440, 10.29, 1.42, 0.04, 0.68, 1.42 and 4.02 mg/m(2)/year, respectively. While the dry deposition fluxes were enriched in Cd, Cu, Pb and Zn indicating their dominant anthropogenic sources, they appeared to be less influenced compared to the neighboring Mediterranean area and other industrial countries, but were similar to or slightly higher than those in remote areas. The enrichment values for Fe and Mn were low, consistent with their crustal origin. The fluxes of all elements suggested the impacts of both crustal (due to climate change) and anthropogenic sources became stronger in this region. The Sahara dust was probably a minor contributor to dry deposition in the GoA.

  15. Construction of a methodologically consistent time series of substance loads and their impacts in Germany. Pt. 1. Comparison of the calculated dry deposition fluxes for 2005 and 2020; Erstellung einer methodenkonsistenten Zeitreihe von Stoffeintraegen und ihren Wirkungen in Deutschland. T. 1. Comparison of the calculated dry deposition fluxes for 2005 and 2020. Genfer Luftreinhaltekonvention der UNECE

    Energy Technology Data Exchange (ETDEWEB)

    Wichink Kruit, Roy; Boersen, Gerbrand; Schaap, Martijn; Builtjes, Peter [TNO Niederlande, Utrecht (Netherlands)

    2013-01-15

    The LOTOS-EUROS model is used to determine the dry deposition flux. A comparison is made between the calculated dry deposition using the projected emissions in 2020 for Germany, accounting for the reductions under the current legislation, and the calculated dry deposition fluxes using the PAREST 2005 emission database.

  16. Dry Deposition Velocity Estimation for the Savannah River Site: Part 1 – Parametric Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Napier, Bruce A.

    2012-01-16

    Values for the dry deposition velocity of airborne particles were estimated with the GENII Version 2.10 computer code for the Savannah River site using assumptions about surface roughness parameters and particle size and density. Use of the GENII code is recommended by the U.S. Department of Energy for this purpose. Meteorological conditions evaluated include atmospheric stability classes D, E, and F and wind speeds of 0.5, 1.0, 1.5, and 3.0 m/s. Local surface roughness values ranging from 0.03 to 2 meters were evaluated. Particles with mass mean diameters of 1, 5, and 10 microns and densities of 1, 3, and 5 g/cm3 were evaluated.

  17. Dry Deposition, Surface Production and Dynamics of Aerosols in the Marine Boundary Layer

    DEFF Research Database (Denmark)

    Fairall, C.W.; Larsen, Søren Ejling

    1984-01-01

    A model of downward aerosol panicle flux characterized by dry deposition velocity, Vd, due to Slinn and Slinn (1980) is generalized to the case of nonzero surface concentration (absorbing surface with a surface source). A more general expression for the flux at some reference height is developed...... which includes Vd and an effective surface source strength, Si, which is a function of the true surface source strength, Si, and the particle transport properties below the reference height. The general expression for the surface flux is incorporated into a dynamic mixed layer model of the type...... developed by Davidson et al. (1983). This three layer model (diffusion sublayer, turbulent surface layer and mixed layer) is applied to an open ocean marine regime where boundary layer advection is ignored. The aerosol concentration in the boundary layer is considered to consist of sea salt particles...

  18. Depositing nanoparticles on a silicon substrate using a freeze drying technique

    Science.gov (United States)

    Sigehuzi, Tomoo

    2017-08-01

    For the microscopic observation of nanoparticles, an adequate sample preparation is an essential part of this task. Much research has been performed for usable preparation methods that will yield aggregate-free samples. A freeze drying technique, which only requires a -80 °C freezer and a freeze dryer, is shown to provide an on-substrate dispersion of mostly isolated nanoparticles. The particle density could be made sufficiently high for efficient observations using atomic force microscopy. Since this sandwich method is purely physical, it could be applied to deposit various nanoparticles independent of their surface chemical properties. Suspension film thickness, or the dimensionality of the suspension film, was shown to be crucial for the isolation of the particles. Silica nanoparticles were dispersed on a silicon substrate using this method and the sample properties were examined using atomic force microscopy.

  19. Dry deposition velocity of atmospheric nitrogen in a typical red soil agro-ecosystem in Southeastern China.

    Science.gov (United States)

    Zhou, Jing; Cui, Jian; Fan, Jian-ling; Liang, Jia-ni; Wang, Ti-jian

    2010-08-01

    Atmospheric dry deposition is an important nitrogen (N) input to farmland ecosystems. The main nitrogen compounds in the atmosphere include gaseous N (NH3, NO2, HNO3) and aerosol N (NH4+/NO3-). With the knowledge of increasing agricultural effects by dry deposition of nitrogen, researchers have paid great attention to this topic. Based on the big-leaf resistance dry deposition model, dry N deposition velocities (Vd) in a typical red soil agro-ecosystem, Yingtan, Jiangxi, Southeastern China, were estimated with the data from an Auto-Meteorological Experiment Station during 2004-2007. The results show that hourly deposition velocities (Vdh) were in the range of 0.17-0.34, 0.05-0.24, 0.57-1.27, and 0.05-0.41 cm/s for NH3, NO2, HNO3, and aerosol N, respectively, and the Vdh were much higher in daytime than in nighttime and had a peak value around noon. Monthly dry deposition velocities (Vdm) were in the range of 0.14-0.36, 0.06-0.18, and 0.07-0.25 cm/s for NH3, NO2, and aerosol N, respectively. Their minimum values appeared from June to August, while their maximum values occurred from February to March each year. The maximum value for HNO3 deposition velocities appeared in July each year, and Vdm(HNO3) ranged from 0.58 to 1.31 cm/s during the 4 years. As for seasonal deposition velocities (Vds), Vds(NH3), Vds(NO2), and Vds(aerosol N) in winter or spring were significantly higher than those in summer or autumn, while Vds(HNO3) in summer were higher than that in winter. In addition, there is no significant difference among all the annual means for deposition velocities (Vda). The average values for NH3, NO2, HNO3, and aerosol N deposition velocities in the 4 years were 0.26, 0.12, 0.81, and 0.16 cm/s, respectively. The model is convenient and feasible to estimate dry deposition velocity of atmospheric nitrogen in the typical red soil agro-ecosystem.

  20. The interconnection of wet and dry deposition and the alteration of deposition budgets due to incorporation of new process understanding in regional models

    Science.gov (United States)

    Dennis, R. L.; Bash, J. O.; Foley, K. M.; Gilliam, R.; Pinder, R. W.

    2013-12-01

    Deposition is affected by the chemical and physical processes represented in the regional models as well as source strength. The overall production and loss budget (wet and dry deposition) is dynamically connected and adjusts internally to changes in process representation. In addition, the scrubbing of pollutants from the atmosphere by precipitation is one of several processes that remove pollutants, creating a coupling with the atmospheric aqueous and gas phase chemistry that can influence wet deposition rates in a nonlinear manner. We explore through model sensitivities with the regional Community Multiscale Air Quality (CMAQ) model the influence on wet and dry deposition, and the overall continental nitrogen budget, of changes in three process representations in the model: (1) incorporation of lightning generated NO, (2) improved representation of convective precipitation, and (3) replacement of the typical unidirectional dry deposition of NH3 with a state of the science representation of NH3 bi-directional air-surface exchange. Results of the sensitivity studies will be presented. (1) Incorporation of lightning generated NO significantly reduces a negative bias in summer wet nitrate deposition, but is sensitive to the choice of convective parameterization. (2) Use of a less active trigger of convective precipitation in the WRF meteorological model to reduce summertime precipitation over prediction bias reduces the generation of NO from lightning. It also reduces the wet deposition of nitrate and increases the dry deposition of oxidized nitrogen, as well as changing (reducing) the surface level exposure to ozone. Improvements in the convective precipitation processes also result in more non-precipitating clouds leading to an increase in SO4 production through the aqueous pathway resulting in improvements in summertime SO4 ambient aerosol estimates.(3) Incorporation of state of the science ammonia bi-directional air surface exchange affects both the dry

  1. Spatial and seasonal variations of atmospheric sulfur concentrations and dry deposition at 16 rural and suburban sites in China

    Science.gov (United States)

    Luo, Xiaosheng; Pan, Yuepeng; Goulding, Keith; Zhang, Lin; Liu, Xuejun; Zhang, Fusuo

    2016-12-01

    The large emissions of sulfur dioxide (SO2) in China have raised worldwide concerns due to its contribution to acid rain and particulate pollution. Monitoring sulfur (S) concentrations and estimating its deposition are important for evaluating air quality and its effects on ecosystems and human health. To date atmospheric dry S deposition in China remains unclear due to the paucity of measurements, especially in rural regions where the ecosystems are sensitive to acid deposition. In this study, we monitored both SO2 and particulate SO42- (pSO42-) concentrations at 8 sites south and 8 sites north of the Huai River in rural and suburban parts of China between 2010 and 2012. The measured concentration of SO2 and pSO42- were combined with GEOS-Chem modeled dry deposition velocities to estimate dry S deposition inputs to the surfaces. SO2 and pSO42- concentrations were high from October/November to next March/April and they (esp. SO2) decreased sharply since March/April at the northern sites, reflecting elevated SO2 emissions by winter heating (which normally starts in October/November and ends in March/April in the north of the Huai River). However the southern sites did not show this trend. Annual dry deposition of SO2 plus pSO42- in this study ranged from 3.1 to 27.1 kg S ha-1 across all the sites in the year 2011 (except one site from May 2011 to April 2012) and showed large spatial variation. The sites in northern China had greater dry deposition due to the higher S concentrations compared with sites in southern China. We also found relatively low pSO42-/pNO3- ratios at most sites, reflecting NOx emissions had a larger influence than SO2 emissions on particle composition during the 2010-2012 period at the measurement sites. Our results suggest that dry S deposition is still important input to ecosystems in spite of slow reduction of Chinese national SO2 emissions since 2005. More research on both wet and dry S deposition and their impacts on the environment and

  2. Projecting Ammonia Dry Deposition Using Passive Samplers and a Bi-Directional Exchange Model

    Science.gov (United States)

    Robarge, W. P.; Walker, J. T.; Austin, R. E.

    2011-12-01

    Animal agriculture within the United States is known to be a source of ammonia (NH3) emissions. Dry deposition of NH3 to terrestrial ecosystems immediately surrounding large local sources of NH3 emissions (e.g. animal feeding operations) is difficult to measure, and is best estimated via models. Presented here are results for a semi-empirical modeling approach for estimating air-surface exchange fluxes of NH3 downwind of a large poultry facility (~ 3.5 million layers) using a bi-directional air-surface exchange model. The modeling domain is the western section of the Pocosin Lakes National Wildlife Refuge in Tyrrell, Washington, and Hyde Counties of eastern North Carolina in the South Atlantic Coastal Plain physiographic region. Vegetation within the modeling domain is primarily pocosin wetlands, characterized by acid (pH 3.6) peat soils and a thick canopy of shrub vegetation (leatherwood (Cyrilla racemiflora), inkberry (Ilex glabra), wax myrtle (Morella cerifera)). Land surrounding the refuge is primarily used for crop production: ~ 28%, 24%, and 45% agricultural in Tyrell, Hyde, and Washington counties, respectively. Ammonia air-surface exchange (flux) was calculated using a two-layer canopy compensation point model developed by Nemitz et al. (2001. Quart. J. Roy. Met. Soc. 127, 815 - 833.) as implemented by Walker et al. (2008. Atmos. Environ., 42, 3407 - 3418.), in which the competing processes of emission and deposition within the foliage-soil system were taken into account by relating the net canopy-scale NH3 flux to the net emission potential of the canopy (i.e., foliage and soil). Ammonia air concentrations were measured using ALPHA passive samplers (Center for Ecology and Hydrology, Edinburgh) along transects to the north and northeast of the poultry facility at distances of 800, 2000 and 3200 m, respectively. Samplers were deployed in duplicate at each location at a height of 5.8 m from July 2008 to July 2010 weekly during warm months and bi-weekly curing

  3. Emission and dry deposition of accumulation mode particles in the Amazon Basin

    Directory of Open Access Journals (Sweden)

    L. Ahlm

    2010-11-01

    Full Text Available Size-resolved vertical aerosol number fluxes of particles in the diameter range 0.25–2.5 μm were measured with the eddy covariance method from a 53 m high tower over the Amazon rain forest, 60 km NNW of Manaus, Brazil. This study focuses on data measured during the relatively clean wet season, but a shorter measurement period from the more polluted dry season is used as a comparison.

    Size-resolved net particle fluxes of the five lowest size bins, representing 0.25–0.45 μm in diameter, were in general dominated by deposition in more or less all wind sectors in the wet season. This is an indication that the source of primary biogenic aerosol particles may be small in this particle size range. Transfer velocities within this particle size range were observed to increase linearly with increasing friction velocity and increasing particle diameter.

    In the diameter range 0.5–2.5 μm, vertical particle fluxes were highly dependent on wind direction. In wind sectors where anthropogenic influence was low, net upward fluxes were observed. However, in wind sectors associated with higher anthropogenic influence, deposition fluxes dominated. The net upward fluxes were interpreted as a result of primary biogenic aerosol emission, but deposition of anthropogenic particles seems to have masked this emission in wind sectors with higher anthropogenic influence. The net emission fluxes were at maximum in the afternoon when the mixed layer is well developed, and were best correlated with horizontal wind speed according to the equation

    log10 F=0.48 · U+2.21

    where F is the net emission number flux of 0.5–2.5 μm particles [m−2 s−1] and U is the horizontal wind speed [ms−1] at the top of the tower.

  4. Carbonaceous species in atmospheric aerosols from the Krakow area (Malopolska District: carbonaceous species dry deposition analysis

    Directory of Open Access Journals (Sweden)

    Szramowiat Katarzyna

    2016-01-01

    Full Text Available Organic and elemental carbon content in PM10 was studied at three sites in Malopolska District representing the city centre (Krakow, rural/residential (Bialka and residential/industrial environments (Krakow. The PM10 samples were collected during the winter time study. The highest concentrations of carbonaceous species were observed in Skawina (36.9 μg·m-3 of OC and 9.6 μg·m-3 of EC. The lowest OC and EC concentrations were reported in Krakow (15.2 μg·m-3 and 3.9 μg·m-3, respectively. The highest concentration of carbonaceous species and the highest wind velocities in Skawina influenced the highest values of the dry deposition fluxes. Correlations between OC, EC and chemical constituents and meteorological parameters suggest that a Krakow was influenced by local emission sources and temperature inversion occurrence; b Bialka was under the influence of local emission sources and long-range transport of particles; c Skawina was impacted by local emission sources.

  5. Wear mechanism for spray deposited Al-Si/SiCp composites under dry sliding condition

    Institute of Scientific and Technical Information of China (English)

    滕杰; 李华培; 陈刚

    2015-01-01

    Al-Si/15%SiCp (volume fraction) composites with different silicon contents were fabricated by spray deposition technique, and typical microstructures of these composites were studied by optical microscopy (OM). Dry sliding wear tests were carried out using a block-on-ring wear machine to investigate the effect of applied load range of 10−220 N on the wear and friction behavior of these composites sliding against SAE 52100 grade bearing steel. Scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDAX) were utilized to examine the morphologies of the worn surfaces in order to observe the wear characteristics and investigate the wear mechanism. The results show that the wear behavior of these composites is dependent on the silicon content in the matrix alloy and the applied load. Al-Si/15%SiCp composites with higher silicon content exhibit better wear resistance in the applied load range. Under lower loads, the major wear mechanisms are oxidation wear and abrasive wear for all tested composites. Under higher loads, severe adhesive wear becomes the main wear mechanisms for Al-7Si/15%SiCp and Al-13Si/15%SiCp composites, while Al-20Si/15%SiCp presents a compound wear mechanism, consisting of oxidation, abrasive wear and adhesion wear.

  6. 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

  7. 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

  8. Field measurements of dry deposition to spruce foliage and petri dishes in the black forest, F.R.G.

    Science.gov (United States)

    Shanley, James B.

    Dry deposition fluxes of Ca 2+, Mg 2+ , K +, Mn 2+, Pb 2+ and SO 2-4 to spruce foliage and petri dishes were measured in two high-elevation sites ( > 900 m) in the southern Black Forest, F.R.G., during 12 periods (2-7 days, each) from mid-September to mid-November, 1983, In situ extraction of deposited material from small spruce branches allowed repeated use of the same foliar collecting surfaces for a direct comparison of deposition between periods. Fluxes were corrected for leaching of internally cycled constituents using factors determined from serial extraction experiments. The ratio of flux to petri dishes vs foliage ( P/F) was > 1.0 for Ca 2+, Pb 2+ and SO 2-4, and somewhat < 1.0 but more constant for Mg 2+ . Temporal variations in dry deposition fluxes at an exposed site near the industrialized Rhine Valley correlated with variations in total air particulate concentrations at a nearby air quality station. Deposition rates were comparable in magnitude but different in temporal pattern at a remote site in the Black Forest interior. Fluxes at each site reached a minimum during the period of 4-9 November when a regional air inversion confined pollutants to the Rhine Valley below the study sites. High fluxes accompanied the inversion break-up.

  9. A Review on Modeling and Monitoring of Dust Dry Deposition%粉尘干沉降研究

    Institute of Scientific and Technical Information of China (English)

    李卓群; 张洁; 黄宁; 邵亚平; 郑晓静

    2011-01-01

    粉尘在地球系统中的循环是一个受到广泛关注的研究领域,而粉尘干沉降是该循环中的关键一环.从粉尘干沉降的基本特征入手,分析粉尘在大气边界层中的运动规律和地表收集粉尘的物理过程;结合颗粒性质,地表特征以及流场条件等因素,对粉尘干沉降的研究工作进行了简要的回顾;分析并比较了现有的粉尘干沉降方案和实验结果,对影响粉尘干沉降过程的主要因素进行了讨论.通过对已有工作的总结和分析,指出了粉尘干沉降研究中存在的主要问题及其发展趋势.%Dust dry deposition is a key component of the dust cycle in the earth system. In this review paper, we first outline the basic characteristics of dust motion in the atmospheric boundary layer and the dust collection processes at the surface. The effect of the physical features of the surface on the efficiency of dust collection is discussed. The dust dry deposition schemes are reviewed, considering dust property, surface character and wind field conditions. A summary of dry deposition schemes, measurements and model-measurement comparisons is then presented. The remaining challenges in dry deposition modeling and monitoring are discussed.

  10. Quantification of Gaseous Elemental Mercury Dry Deposition to Environmental Surfaces using Mercury Stable Isotopes in a Controlled Environment

    Science.gov (United States)

    Rutter, A. P.; Schauer, J. J.; Shafer, M. M.; Olson, M.; Robinson, M.; Vanderveer, P.; Creswell, J. E.; Parman, A.; Mallek, J.; Gorski, P.

    2009-12-01

    Andrew P. Rutter (1) * *, James J, Schauer (1,2) *, Martin M. Shafer(1,2), Michael R. Olson (1), Michael Robinson (1), Peter Vanderveer (3), Joel Creswell (1), Justin L. Mallek (1), Andrew M. Parman (1) (1) Environmental Chemistry and Technology Program, 660 N. Park St, Madison, WI 53705. (2) Wisconsin State Laboratory of Hygiene, 2601 Agriculture Drive, Madison, WI 53718. (3) Biotron, University of Wisconsin - Madison, 2115 Observatory Drive, Madison, WI 53706 * Correspond author(jjschauer@wisc.edu) * *Presenting author (aprutter@wisc.edu) Abstract Gaseous elemental mercury (GEM) is the predominant component of atmospheric mercury outside of arctic depletion events, and locations where anthropogenic point sources are not influencing atmospheric concentrations. GEM constitutes greater than 99% of the mercury mass in most rural and remote locations. While dry and wet deposition of atmospheric mercury is thought to be dominated by oxidized mercury (a.k.a. reactive mercury), only small GEM uptake to environmental surfaces could impact the input of mercury to terrestrial and aquatic ecosystems. Dry deposition and subsequent re-emission of gaseous elemental mercury is a pathway from the atmosphere that remains only partially understood from a mechanistic perspective. In order to properly model GEM dry deposition and re-emission an understanding of its dependence on irradiance, temperature, and relative humidity must be measured and parameterized for a broad spectrum of environmental surfaces colocated with surrogate deposition surfaces used to make field based dry deposition measurements. Measurements of isotopically enriched GEM dry deposition were made with a variety of environmental surfaces in a controlled environment room at the University of Wisconsin Biotron. The experimental set up allowed dry deposition components which are not easily separated in the field to be decoupled. We were able to isolate surface transfer processes from variabilities caused by

  11. A Blue Spectral Shift of the Hemoglobin Soret Band Correlates with the Age (Time Since Deposition) of Dried Bloodstains

    Science.gov (United States)

    Hanson, Erin K.; Ballantyne, Jack

    2010-01-01

    The ability to determine the time since deposition of a bloodstain found at a crime scene could prove invaluable to law enforcement investigators, defining the time frame in which the individual depositing the evidence was present. Although various methods of accomplishing this have been proposed, none has gained widespread use due to poor time resolution and weak age correlation. We have developed a method for the estimation of the time since deposition (TSD) of dried bloodstains using UV-VIS spectrophotometric analysis of hemoglobin (Hb) that is based upon its characteristic oxidation chemistry. A detailed study of the Hb Soret band (λmax = 412 nm) in aged bloodstains revealed a blue shift (shift to shorter wavelength) as the age of the stain increases. The extent of this shift permits, for the first time, a distinction to be made between bloodstains that were deposited minutes, hours, days and weeks prior to recovery and analysis. The extent of the blue shift was found to be a function of ambient relative humidity and temperature. The method is extremely sensitive, requiring as little as a 1 µl dried bloodstain for analysis. We demonstrate that it might be possible to perform TSD measurements at the crime scene using a portable low-sample-volume spectrophotometer. PMID:20877468

  12. 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

    2008-03-01

    VWM concentrations around the mean (1994–2005 presents fluctuations between ±5% and ±30% mainly attributed to the variations of sources strength associated with rainfall spatio-temporal distribution. From 1994 to 2005, the total mean wet deposition flux in the Sahelian region is 60.1 mmol.m−2.yr−1 and fluctuates around ±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 loadings presents a strong negative gradient from the dry savanna to the forest (143.7, 100.2 to 86.6 μeq.l–1, associated with the gradient of terrigeneous compounds sources. The wet deposition fluxes present an opposite gradient, 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 the rainfall gradient along the ecosystems transect.

  13. 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.

  14. Dry deposition of acidic air pollutants to tree leaves, determined by a modified leaf-washing technique

    Science.gov (United States)

    Watanabe, Mirai; Takamatsu, Takejiro; Koshikawa, Masami K.; Yamamura, Shigeki; Inubushi, Kazuyuki

    Dry deposition fluxes ( FL) of NO 3- and SO 42- to leaf surfaces were measured for Japanese red pine ( Pinus densiflora), Japanese cedar ( Cryptomeria japonica), Japanese cypress ( Chamaecyparis obtusa), and Japanese white oak ( Quercus myrsinaefolia), together with atmospheric concentrations ( CL) of NO x (NO + NO 2), T-NO 3 (gaseous HNO 3 + particulate NO 3-) and SO x (gaseous SO 2 + particulate SO 42-) around the leaves in a suburban area of Japan, using a modified leaf-washing technique. FL of NO 3- and SO 42- decreased as follows: pine >> cedar > cypress ≥ oak and pine >> cedar > oak ≥ cypress, respectively. FL of NO 3- for all tree species fluctuated synchronously with CL of T-NO 3. FL of SO 42- fluctuated with CL of SO x, but the dominant pollutant deposited (SO 2 or SO 42-) appeared to differ for different tree species. Dry deposition conductance ( KL) of T-NO 3 and SO x was derived as an FL/ CL ratio. Seasonal variations of KL likely reflect the gas/particle ratios of T-NO 3 and SO x, which were affected by meteorological conditions such as temperature. Dry deposition velocities ( Vd) of T-NO 3 and SO x were obtained as the mathematical product of annual mean KL and the total leaf surface areas in the forests. The comparison of Vd among tree species indicated that the loads of acidic air pollutants were higher to coniferous forests than broad-leaved forest because of the higher KL and/or larger leaf surface areas.

  15. Photocatalytic evaluation of self-assembled porous network structure of ferric oxide film fabricated by dry deposition process

    Energy Technology Data Exchange (ETDEWEB)

    Park, Yunchan; Kim, Hyungsub; Lee, Geon-Yong; Pawar, Rajendra C.; Lee, Jai-Sung; Lee, Caroline Sunyong, E-mail: sunyonglee@hanyang.ac.kr

    2016-09-15

    Ferric oxide powder in the alpha phase (α-Fe{sub 2}O{sub 3}) was deposited on an aluminum oxide (Al{sub 2}O{sub 3}) substrate by a nanoparticle deposition system using the dry deposition method. X-ray diffraction (XRD) images confirmed that the phase of the deposited α-Fe{sub 2}O{sub 3} did not change. The deposited α-Fe{sub 2}O{sub 3} was characterized in terms of its microstructure using scanning electron microscopy (SEM). A porous network microstructure formed when small agglomerates of Fe{sub 2}O{sub 3} (SAF) were deposited. The deposition and formation mechanism of the microstructure were investigated using SEM and three-dimensional (3D) profile analysis. First, a dense coating layer formed when the film was thinner than the particle size. After that, as the film thickness increased to over 5 μm, the porous network structure formed by excavating the surface of the coating layer as it was bombarded by particles. Rhodamine B (RhB) was degraded after 6 h of exposure to the Fe{sub 2}O{sub 3} coating layer with SAF, which has good photocatalytic activity and a high porous network structure. The kinetic rate constants of the SAF and large agglomerates of Fe{sub 2}O{sub 3} (LAF) were calculated to be 0.197(h{sup −1}) and 0.128(h{sup −1}), respectively, based on the absorbance results. Using linear sweep voltammetry, we confirmed that the photoelectric effect occurred in the coating layer by measuring the resulting current under illuminated and dark conditions. - Graphical abstract: Self-assembled porous photocatalytic film fabricated by dry deposition method for water purification. - Highlights: • Different sizes of Fe{sub 2}O{sub 3} agglomerates were used to form porous network structure. • Fe{sub 2}O{sub 3} agglomerate particles were deposited using solvent-free process. • Self-assembled porous network microstructure formed better with small agglomerates of Fe{sub 2}O{sub 3}. • Fabricated porous network structure showed its potential to be used

  16. Dry-spray deposition of TiO2 for a flexible dye-sensitized solar cell (DSSC) using a nanoparticle deposition system (NPDS).

    Science.gov (United States)

    Kim, Min-Saeng; Chun, Doo-Man; Choi, Jung-Oh; Lee, Jong-Cheon; Kim, Yang Hee; Kim, Kwang-Su; Lee, Caroline Sunyong; Ahn, Sung-Hoon

    2012-04-01

    TiO2 powders were deposited on indium tin oxide (ITO) coated polyethylene terephthalate (PET) substrates for application to the photoelectrode of a dye-sensitized solar cell (DSSC). In the conventional DSSC manufacturing process, a semiconductor oxide such as TiO2 powder requires a sintering process at higher temperature than the glass transition temperature (T(g)) of polymers, and thus utilization of flexible polymer substrates in DSSC research has been constrained. To overcome this restriction related to sintering, we used a nanoparticle deposition system (NPDS) that could produce a thin coating layer through a dry-spray method under atmospheric pressure at room temperature. The powder was sprayed through a slit-type nozzle having a 0.4 x 10 mm2 rectangular outlet. In order to determine the deposited TiO2 thickness, five kinds of TiO2 layered specimens were prepared, where the specimens have single and double layer structures. Deposited powders on the ITO coated PET substrates were observed using FE-SEM and a scan profiler The thicker TiO2 photoelectrode with a DSSC having a double layer structure showed higher energy efficiency than the single layer case. The highest fabricated flexible DSSC displayed a short circuit current density J(sc) = 1.99 mA cm(-2), open circuit voltage V(oc) = 0.71 V, and energy efficiency eta = 0.94%. These results demonstrate the possibility of utilizing the dry-spray method to fabricate a TiO2 layer on flexible polymer substrates at room temperature under atmospheric pressure.

  17. 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

    2014-12-01

    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 deposition fluxes of PBDEs, respectively.

  18. Error estimations of dry deposition velocities of air pollutants using bulk sea surface temperature under common assumptions

    Science.gov (United States)

    Lan, Yung-Yao; Tsuang, Ben-Jei; Keenlyside, Noel; Wang, Shu-Lun; Arthur Chen, Chen-Tung; Wang, Bin-Jye; Liu, Tsun-Hsien

    2010-07-01

    It is well known that skin sea surface temperature (SSST) is different from bulk sea surface temperature (BSST) by a few tenths of a degree Celsius. However, the extent of the error associated with dry deposition (or uptake) estimation by using BSST is not well known. This study tries to conduct such an evaluation using the on-board observation data over the South China Sea in the summers of 2004 and 2006. It was found that when a warm layer occurred, the deposition velocities using BSST were underestimated within the range of 0.8-4.3%, and the absorbed sea surface heat flux was overestimated by 21 W m -2. In contrast, under cool skin only conditions, the deposition velocities using BSST were overestimated within the range of 0.5-2.0%, varying with pollutants and the absorbed sea surface heat flux was underestimated also by 21 W m -2. Scale analysis shows that for a slightly soluble gas (e.g., NO 2, NO and CO), the error in the solubility estimation using BSST is the major source of the error in dry deposition estimation. For a highly soluble gas (e.g., SO 2), the error in the estimation of turbulent heat fluxes and, consequently, aerodynamic resistance and gas-phase film resistance using BSST is the major source of the total error. In contrast, for a medium soluble gas (e.g., O 3 and CO 2) both the errors from the estimations of the solubility and aerodynamic resistance are important. In addition, deposition estimations using various assumptions are discussed. The largest uncertainty is from the parameterizations for chemical enhancement factors. Other important areas of uncertainty include: (1) various parameterizations for gas-transfer velocity; (2) neutral-atmosphere assumption; (3) using BSST as SST, and (4) constant pH value assumption.

  19. The impact of atmospheric dry deposition associated microbes on the southeastern Mediterranean Sea surface water following an intense dust storm

    Directory of Open Access Journals (Sweden)

    Eyal Rahav

    2016-07-01

    Full Text Available This study explores the potential impacts of microbes deposited into the surface seawater of the southeastern Mediterranean Sea (SEMS along with atmospheric particles on marine autotrophic and heterotrophic production. We compared in situ changes in autotrophic and heterotrophic microbial abundance and production rates before and during an intense dust storm event in early September 2015. Additionally, we measured the activity of microbes associated with atmospheric dry deposition (also referred to as airborne microbes in sterile SEMS water using the same particles collected during the dust storm. A high diversity of prokaryotes and a low diversity of autotrophic eukaryotic algae were delivered to surface SEMS waters by the storm. Autotrophic airborne microbial abundance and activity were low, contributing ~1% of natural abundance in SEMS water and accounting for 1-4% to primary production. Airborne heterotrophic bacteria comprised 30-50% of the cells and accounted for 13-42% of bacterial production. Our results demonstrate that atmospheric dry deposition may supply not only chemical constitutes but also microbes that can affect ambient microbial populations and their activity in the surface ocean. Airborne microbes may play a greater role in ocean biogeochemistry in the future in light of the expected enhancement of dust storm durations and frequencies due to climate change and desertification processes.

  20. An improved parameterisation of ozone dry deposition to the ocean and its impact in a global climate-chemistry model

    Science.gov (United States)

    Luhar, Ashok K.; Galbally, Ian E.; Woodhouse, Matthew T.; Thatcher, Marcus

    2017-03-01

    Schemes used to parameterise ozone dry deposition velocity at the oceanic surface mainly differ in terms of how the dominant term of surface resistance is parameterised. We examine three such schemes and test them in a global climate-chemistry model that incorporates meteorological nudging and monthly-varying reactive-gas emissions. The default scheme invokes the commonly used assumption that the water surface resistance is constant. The other two schemes, named the one-layer and two-layer reactivity schemes, include the simultaneous influence on the water surface resistance of ozone solubility in water, waterside molecular diffusion and turbulent transfer, and a first-order chemical reaction of ozone with dissolved iodide. Unlike the one-layer scheme, the two-layer scheme can indirectly control the degree of interaction between chemical reaction and turbulent transfer through the specification of a surface reactive layer thickness. A comparison is made of the modelled deposition velocity dependencies on sea surface temperature (SST) and wind speed with recently reported cruise-based observations. The default scheme overestimates the observed deposition velocities by a factor of 2-4 when the chemical reaction is slow (e.g. under colder SSTs in the Southern Ocean). The default scheme has almost no temperature, wind speed, or latitudinal variations in contrast with the observations. The one-layer scheme provides noticeably better variations, but it overestimates deposition velocity by a factor of 2-3 due to an enhancement of the interaction between chemical reaction and turbulent transfer. The two-layer scheme with a surface reactive layer thickness specification of 2.5 µm, which is approximately equal to the reaction-diffusive length scale of the ozone-iodide reaction, is able to simulate the field measurements most closely with respect to absolute values as well as SST and wind-speed dependence. The annual global oceanic deposition of ozone determined using this

  1. Atmospheric total gaseous mercury (TGM concentrations and wet and dry deposition of mercury at a high-altitude mountain peak in south China

    Directory of Open Access Journals (Sweden)

    H. Zhang

    2009-11-01

    Full Text Available China is regarded as the largest contributor of mercury (Hg to the global atmospheric Hg budget. However, concentration levels and depositions of atmospheric Hg in China are poorly known. Continuous measurements of atmospheric total gaseous mercury (TGM were carried out from May 2008 to May 2009 at the summit of Mt. Leigong in south China. Wet and dry deposition fluxes of Hg were also calculated following collection of precipitation, throughfall and litterfall. Atmospheric TGM concentrations averaged 2.80±1.51 ng m−3, which was highly elevated compared to global background values but much lower than semi-rural and industrial/urban areas in China, indicating great emissions of Hg in central, south and southwest China. Seasonal and diurnal variations of TGM were observed, which reflected variations in source intensity, deposition processes and meteorological factors. Wet deposition of Hg was quite low, while its dry deposition of Hg (litterfall + throughfall-direct wet deposition constituted a major portion of total deposition (~88% for total mercury (THg and 84% for methyl mercury (MeHg. This highlights the importance of vegetation to Hg atmospheric cycling. In a remote forest ecosystem of China, dry deposition of TGM, especially gaseous elemental mercury (GEM, was very important for the depletion of atmospheric Hg. Elevated TGM level in ambient air may accelerate the foliar uptake of Hg through air which may partly explain the elevated Hg dry deposition fluxes observed in Mt. Leigong.

  2. Parameterization of gaseous dry deposition in atmospheric chemistry models: Sensitivity to aerodynamic resistance formulations under statically stable conditions

    Science.gov (United States)

    Toyota, Kenjiro; Dastoor, Ashu P.; Ryzhkov, Andrei

    2016-12-01

    Turbulence controls the vertical transfer of momentum, heat and trace constituents in the atmospheric boundary layer. In the lowest 10% of this layer lies the surface boundary layer (SBL) where the vertical fluxes of transferred quantities have been successfully parameterized using the Monin-Obukhov similarity theory in weather forecast, climate and atmospheric chemistry models. However, there is a large degree of empiricism in the stability-correction parameterizations used to formulate eddy diffusivity and aerodynamic resistance particularly under strongly stable ambient conditions. Although the influence of uncertainties in stability-correction parameterizations on eddy diffusivity is actively studied in boundary-layer meteorological modeling, its impact on dry deposition in atmospheric chemistry modeling is not well characterized. In this study, we address this gap by providing the mathematical basis for the relationship between the formulations of vertical surface flux used in meteorological and atmospheric chemistry modeling communities, and by examining the sensitivity of the modeled dry deposition velocities in statically stable SBL to the choice of stability-correction parameterizations used in three operational and/or research environmental models (GEM/GEM-MACH, ECMWF IFS and CMAQ-MM5). Aerodynamic resistances (ra) calculated by the three sets of parameterizations are notably different from each other and are also different from those calculated by a "z-less" scaling formulation under strongly stable conditions (the bulk Richardson number > 0.2). Furthermore, we show that many atmospheric chemistry models calculate ra using formulations which are inconsistent with the derivation of micro-meteorological parameters. Finally, practical implications of the differences in stability-correction algorithms are discussed for the computations of dry deposition velocities of SO2, O3 and reactive bromine compounds for specific cases of stable SBL.

  3. Dry Deposition Velocity Estimation for the Savannah River Site: Part 2 -- Parametric and Site-Specific Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Napier, Bruce A.; Rishel, Jeremy P.; Cook, Kary M.

    2013-09-12

    Values for the dry deposition velocity of airborne particles were estimated with the GENII Version 2.10.1 computer code for the Savannah River site using assumptions about surface roughness parameters and particle size and density. Use of the GENII code is recommended by the U.S. Department of Energy for this purpose. Meteorological conditions evaluated include atmospheric stability classes D, E, and F and wind speeds of 0.5, 1.0, 1.5, and 2.0 m/s. Local surface roughness values ranging from 0.03 to 2 meters were evaluated. Particles with mass mean diameters of 1, 5, and 10 microns and densities of 1, 3, 4, and 5 g/cm3 were evaluated. Site specific meteorology was used to predict deposition velocity for Savannah River conditions for a range of distances from 670 to 11,500 meters.

  4. Quantifying the dry deposition of ammonia in ammonia-rich and ammonia-poor environments using a surrogate surface approach

    Science.gov (United States)

    Moumen, Nadjoua; Yi, Seung-Muk; Raymond, Heather A.; Han, YoungJi; Holsen, Thomas M.

    In this study, dry deposition samples were collected with both an aerodynamically smooth water surface (WSS) and a knife-edge surrogate surface (KSS) in Potsdam, NY, Solomons, MD, and at a farm in upstate NY intermittently between March 2000 and August 2001. The WSS and the citric acid-coated paper filter on the KSS were used to measure total ammonium deposition (NH 3 and p-NH 4+), while a greased Mylar disk on the KSS was used to measure particulate NH 4+ (p-NH 4+) deposition. An annular denuder system (ADS) was used to measure NH 3 gas phase and particulate NH 4+ concentrations. In side-by-side experiments with two WSSs, no statistical difference was found between simultaneously measured total ammonium deposition at any of the sites. Average total NH 3 fluxes measured with the WSS in Potsdam, Solomons, and at the farm were 3.1, 2.1, and 310 mg NH 4+ m -2 day -1, respectively. Similarly gaseous NH 3 fluxes measured with the citric acid-coated paper on the KSS were 3.6, 2.1, and 500 mg NH 4+m -2 day -1, respectively. The p-NH 4+ fluxes to the KSS-greased strip were negligible at all three locations. Fluxes measured by the citric acid paper filters were slightly greater than those measured with the WSS suggesting that the acidic dry surfaces had a higher affinity for ammonia than the water in the WSS. The average gas-phase ammonia concentrations in Potsdam, Solomons, MD and at the farm were 0.60×10 -3, 2.1×10 -3, and 0.25 mg NH 4+ m -3, respectively. The average ammonium concentrations were 0.50×10 -3, 1.2×10 -3, and 14×10 -3 mg NH 4+ m -3, respectively.

  5. The influence of regional circulation patterns on wet and dry mineral dust and sea salt deposition over Greenland

    Energy Technology Data Exchange (ETDEWEB)

    Hutterli, M.A. [University of Bern, Physics Institute, Bern (Switzerland); British Antarctic Survey, Physical Sciences Division, Cambridge (United Kingdom); Crueger, T. [Max-Planck-Institute for Meteorology, Hamburg (Germany); Fischer, H. [Alfred-Wegener-Institute for Polar and Marine Research, Bremerhaven (Germany); Andersen, K.K.; Siggaard-Andersen, M.L. [University of Copenhagen, Niels Bohr Institute, Copenhagen (Denmark); Raible, C.C.; Stocker, T.F. [University of Bern, Physics Institute, Bern (Switzerland); McConnell, J.R. [Desert Research Institute, Reno, NV (United States); Bales, R.C.; Burkhart, J.F. [University of California, Merced, Atwater, CA (United States)

    2007-05-15

    Annually resolved ice core records from different regions over the Greenland ice sheet (GrIS) are used to investigate the spatial and temporal variability of calcium (Ca{sup 2+}, mainly from mineral dust) and sodium (Na{sup +}, mainly from sea salt) deposition. Cores of high common inter-annual variability are grouped with an EOF analysis, resulting in regionally representative Ca{sup 2+} and Na{sup +} records for northeastern and central Greenland. Utilizing a regression and validation method with ERA-40 reanalysis data, these common records are associated with distinct regional atmospheric circulation patterns over the North American Arctic, Greenland, and Central to Northern Europe. These patterns are interpreted in terms of transport and deposition of the impurities. In the northeastern part of the GrIS sea salt records reflect the intrusion of marine air masses from southeasterly flow. A large fraction of the Ca{sup 2+} variability in this region is connected to a circulation pattern suggesting transport from the west and dry deposition. This pattern is consistent with the current understanding of a predominantly Asian source of the dust deposited over the GrIS. However, our results also indicate that a significant fraction of the inter-annual dust variability in NE and Central Greenland is determined by the frequency and intensity of wet deposition during the season of high atmospheric dust loading, rather than representing the variability of the Asian dust source and/or long-range transport to Greenland. The variances in the regional proxy records explained by the streamfunction patterns are high enough to permit reconstructions of the corresponding regional deposition regimes and the associated circulation patterns. (orig.)

  6. Dry deposition of sulphur at a high-altitude background station in South Africa

    CSIR Research Space (South Africa)

    Zunckel, M

    1999-10-01

    Full Text Available and cool nights were experienced during the summer campaign with convective afternoon or evening showers on six occasions. No rain fell during the typically dry winter campaign when cool days and cold nights were experienced. Mean global radiation for the 2...

  7. SEASONAL CHARACTERIZATION OF DUST DAYS,MASS CONCENTRATION AND DRY DEPOSITION OF ATMOSPHERIC AEROSOLS OVER QINGDAO, CHINA

    Institute of Scientific and Technical Information of China (English)

    Renjian Zhang; Mingxing Wang; Lifang Sheng; Yutaka Kanai; Atsuyuki Ohta

    2004-01-01

    The seasonal characterization of dust days, mass concentration and dry deposition of atmospheric aerosols were investigated using the historical data of dust days observed over Qingdao during the period from 1961 to 2001and ground-based aerosol sampling data collected in the period from May 2001 to November 2002. In Qingdao most of the dust days occurred in spring and in winter and no dust days existed in summer. The seasonal variation of the uplifting dust day over Qingdao was in phase with that analyzed over North China. The mean mass concentration of the total values and phase of the seasonal oscillation for fine particles were very similar to those for coarse particles except for the month March, during which the concentration of the coarse particles was about 4 times as high as that of the fine particles. Comparison between seasonal variation of mass concentration of aerosols and dust days indicated that high frequency of uplifting dust day was accompanied by high TSP mass concentration. The TSP mass concentration measured by the low-volume instrument was about 30% lower than that measured by high-volume instrument, though the two data sets are highly correlated (correlation coefficient=0.89). The dry deposition flux during the observation period from as that over Beijing.

  8. Neutral and ionic per- and polyfluoroalkyl substances (PFASs) in atmospheric and dry deposition samples over a source region (Tianjin, China).

    Science.gov (United States)

    Yao, Yiming; Chang, Shuai; Sun, Hongwen; Gan, Zhiwei; Hu, Hongwei; Zhao, Yangyang; Zhang, Yufen

    2016-05-01

    Per- and polyfluoroalkyl substances (PFASs) were detected in the atmosphere of a source region in Tianjin, China. Fluorotelomer alcohols (FTOHs) were the dominant neutral PFASs in the atmosphere with total concentrations of 93.6-131 pg/m(3) and 8:2 FTOH contributing the most, whereas perfluorooctane sulfonamide derivatives (PFOSAs) were two magnitudes lower or undetected. In comparison, ionic PFASs (perfluoroalkyl carboxyl acids (PFCAs)) in the atmosphere were detected at similar or even higher levels. At wastewater treatment plants (WWTPs), the air over influent was found with higher levels of FTOHs than over aeration tank and effluent; whereas in the air over the aeration tank, the concentrations of PFOSAs and nonvolatile ionic PFASs substantially increased, suggesting a possible direct release of ionic PFASs to the atmosphere besides the atmospheric conversion from volatile precursors. In the air phase, a low proportion (1-5%) of PFCAs was subjected to dry deposition in the source region. Interestingly, the dry-deposition-to-bulk-air ratios of PFCA analogues were the lowest at medium chain lengths (C8 and C9) and increased with either shorter or longer chain length. The extraordinary affinity of shorter-chain PFCAs (C6-C7) to particles was presumed to be due to their smaller molecular size favoring the interactions between the carboxyl head groups and specific sorption sites on particulate matter.

  9. 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.

  10. Estimation of the Total Dust Column and Dry Deposition Flux over the Yellow Sea, China Based on Shipboard Sun Photometer Measurements: Case Study

    Institute of Scientific and Technical Information of China (English)

    YANG Dong-Xu; LIU Yi; CHEN Wen-Zhong

    2010-01-01

    The total dust column and the dry deposition flux were calculated based on the optical properties that were measured by a shipboard sun photometer POM-01 MK Ⅱ in a cloud-free and nonfrontal dust condition on 24 April 2006. The total dust column was calculated by using an integration method of the particle size distribution; the mean value was 1.42±0.30 g m-2. A linear correlation between the total dust column and the aerosol optical depth (AOD) with a linear factor of 2.7 g m-2 over the Sahara was applied to calculate the total dust column in this study; the results were lower than these calculated by the integration method. A reasonable factor of 3.2 g m-2 was achieved by minimizing the standard deviation (SD) of the two methods. The two layers model, which includes the deposition processes of turbulent transfer, Brownian diffusion, impaction and gravitational settling over the sea's surface, was used to calculate the dry deposition flux; the mean value was 5.05±2.49 μg m-2 s-1. A correlation among the total dust column, dry deposition flux, AOD, and effective radius was discussed. The correlation between the total dust column and the AOD was better than that between the total dust column and the effective radius; however, the correlation between the dry deposition flux and the effective radius was better than that between the dry deposition flux and the AOD.

  11. Three air quality studies: Great Lakes ozone formation and nitrogen dry deposition; and Tucson aerosol chemical characterization

    Science.gov (United States)

    Foley, Theresa

    (arsenic, beryllium, cadmium, chromium, cobalt, lead, manganese, and nickel) in the southern Tucson metropolitan area. A Tucson company that uses beryllium oxide to manufacture thermally conductive ceramics has prompted strong citizen concern. This study found that the study area has good air quality with respect to PM10 and metals, with ambient concentrations meeting US Environmental Protection Agency and World Health Organization standards. Beryllium was detected only once (during a dust storm) and was ascribed to naturally-occurring beryllium in the suspended soil. The third paper (to be submitted to the Journal of Great Lakes Research) studies nitrogen dry deposition over Lake Michigan and Lake Superior. Numerous studies have shown that wet and dry deposition of nitrogen has contributed to the eutrophication of coastal waters and declining productivity of marine fisheries. Nitrogen dry deposition over the Great Lakes themselves, as opposed to the shorelines, has not been documented in the peer-reviewed literature. This paper calculates nitrogen dry deposition over Lake Michigan and Lake Superior, using aircraft measurements from the LADCO Aircraft Study, and finds that over-water, nitrogen dry deposition is a significant source of nitrogen to Lake Michigan and Lake Superior.

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

    NARCIS (Netherlands)

    Remke, E.; Brouwer, E.; Kooijman, A.; Blindow, I.; Esselink, H.; Roelofs, J.G.M.

    2009-01-01

    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 3-8 kg N ha−1 yr−1. The nitrogen content of Cladonia portentosa appeared to be a suitab

  13. Effect of dry air on interface smoothening in reactive sputter deposited Co/Ti multilayer

    Science.gov (United States)

    Biswas, A.; Porwal, A.; Bhattacharya, Debarati; Prajapat, C. L.; Ghosh, Arnab; Nand, Mangla; Nayak, C.; Rai, S.; Jha, S. N.; Singh, M. R.; Bhattacharyya, D.; Basu, S.; Sahoo, N. K.

    2017-09-01

    Top surface roughness and interface roughness are one of the key elements which determine the performance of X-ray and neutron thin film multilayer devices. It has been observed that by mixing air with argon in sputtering ambience during deposition of Co layers, polarized neutron reflectivity (PNR) of Co/Ti supermirror polarizers can be improved substantially. Cross-sectional HRTEM measurement reveals that sharper interfaces in the supermirror can be achieved in case of deposition of the multilayer under mixed ambience of argon and air. In order to investigate this interface modification mechanism further, in this communication two sets of tri-layer Co/Ti/Co samples and 20-layer Co/Ti periodic multilayer samples have been prepared; in one set all the layers are deposited only under argon ambience and in the other set, Co layers are deposited under a mixed ambience of argon and air. These samples have been characterized by measuring specular and non-specular X-ray reflectivities (GIXR) with X-rays of 1.54 Å wavelength and polarized neutron reflectivity (PNR) with neutron of 2.5 Å wavelength at grazing angle of incidence. It has been observed that the X-ray and neutron specular reflectivities at Bragg peaks of 20 layer periodic multilayer increase when Co layers are deposited under mixed ambience of argon and air. The detail information regarding the effect of air on the interfaces and magnetic properties has been obtained by fitting the measured spectra. The above information has subsequently been supplemented by XRD and magnetic measurements on the samples. XPS and XANES measurements have also been carried out to investigate whether cobalt oxide or cobalt nitride layers are being formed due to use of air in sputtering ambience.

  14. Ring deposition of drying suspension droplets%溶液液滴蒸发变干的环状沉积

    Institute of Scientific and Technical Information of China (English)

    张文彬; 廖龙光; 于同旭; 纪爱玲

    2013-01-01

    Deposition of colloidal particles in a drying droplet is important in many scientific researches and technological applications. In this work, the ring deposition of drying droplets on a solid substrate is investigated experimentally at a microscopic level. A ring deposition is formed at the contact line as the water solution droplet containing SiO2 particles is drying, just like the formation of coffee ring. Contact line pinning is crucial to the ring deposition formation. There will be a replenish flow in the droplet towards the edge, and the particles are driven to the contact line, deposited on the substrate. As the particle mass fraction is large, the particles which are left inside the spot, when the droplet dries out, may form a single particle layer, packing in order. The contact angle of the droplet on glass substrate is very small, the SiO2 particles will gather at the rim of the droplet, which initially form a chain along the contact line. As more particles come to the rim, they are deposited in a line by line way to form a 2D close packing. Since the contact angle decreases with evaporation when the contact line is pinned, a capillary force between liquid surface and particles arises once the height of droplet surface near the contact line is lower than that of the particle, pushing the particles to move inward. The effect on the larger particles is more pronounced-it even leads to a separation of the particles, with the smaller ones at the outer side.%液体蒸发驱动的颗粒自组装现象在许多的工业技术中有重要应用。本文利用显微镜观测含有颗粒物质的液滴变干后留在固体表面的颗粒形成的环状沉积图案。采用微米粒径的SiO2小球水溶液液滴蒸发变干模拟咖啡环的形成过程,结果发现液滴蒸发过程中接触线的钉扎是环状沉积的必要条件。在液滴蒸发过程中颗粒随着补偿流不断的向液滴边缘移动,聚集在接触线处形成环。液滴蒸发变

  15. Development and validation of a size-resolved particle dry deposition scheme for application in aerosol transport models

    Directory of Open Access Journals (Sweden)

    A. Petroff

    2010-12-01

    Full Text Available A size-resolved particle dry deposition scheme is developed for inclusion in large-scale air quality and climate models where the size distribution and fate of atmospheric aerosols is of concern. The "resistance" structure is similar to what is proposed by Zhang et al. (2001, while a new "surface" deposition velocity (or surface resistance is derived by simplification of a one-dimensional aerosol transport model (Petroff et al., 2008b, 2009. Compared to Zhang et al.'s model, the present model accounts for the leaf size, shape and area index as well as the height of the vegetation canopy. Consequently, it is more sensitive to the change of land covers, particularly in the accumulation mode (0.1–1 micron. A drift velocity is included to account for the phoretic effects related to temperature and humidity gradients close to liquid and solid water surfaces. An extended comparison of this model with experimental evidence is performed over typical land covers such as bare ground, grass, coniferous forest, liquid and solid water surfaces and highlights its adequate prediction. The predictions of the present model differ from Zhang et al.'s model in the fine mode, where the latter tends to over-estimate in a significant way the particle deposition, as measured by various investigators or predicted by the present model. The present development is thought to be useful to modellers of the atmospheric aerosol who need an adequate parameterization of aerosol dry removal to the earth surface, described here by 26 land covers. An open source code is available in Fortran90.

  16. Plant hydraulic responses to long-term dry season nitrogen deposition alter drought tolerance in a Mediterranean-type ecosystem.

    Science.gov (United States)

    Pivovaroff, Alexandria L; Santiago, Louis S; Vourlitis, George L; Grantz, David A; Allen, Michael F

    2016-07-01

    Anthropogenic nitrogen (N) deposition represents a significant N input for many terrestrial ecosystems. N deposition can affect plants on scales ranging from photosynthesis to community composition, yet few studies have investigated how changes in N availability affect plant water relations. We tested the effects of N addition on plant water relations, hydraulic traits, functional traits, gas exchange, and leaf chemistry in a semi-arid ecosystem in Southern California using long-term experimental plots fertilized with N for over a decade. The dominant species were Artemisia california and Salvia mellifera at Santa Margarita Ecological Reserve and Adenostoma fasciculatum and Ceanothus greggii at Sky Oaks Field Station. All species, except Ceanothus, showed increased leaf N concentration, decreased foliar carbon to N ratio, and increased foliar N isotopic composition with fertilization, indicating that added N was taken up by study species, yet each species had a differing physiological response to long-term N addition. Dry season predawn water potentials were less negative with N addition for all species except Adenostoma, but there were no differences in midday water potentials, or wet season water potentials. Artemisia was particularly responsive, as N addition increased stem hydraulic conductivity, stomatal conductance, and leaf carbon isotopic composition, and decreased wood density. The alteration of water relations and drought resistance parameters with N addition in Artemisia, as well as Adenostoma, Ceanothus, and Salvia, indicate that N deposition can affect the ability of native Southern California shrubs to respond to drought.

  17. High concentrations and dry deposition of reactive nitrogen species at two sites in the North China Plain

    Energy Technology Data Exchange (ETDEWEB)

    Shen, J.L.; Tang, A.H.; Liu, X.J.; Fangmeier, A.; Goulding, K.T.W.; Zhang, F.S. [China Agricultural University, Beijing (China)

    2009-11-15

    Atmospheric concentrations of major reactive nitrogen (N{sub r}) species were quantified using passive samplers, denuders, and particulate samplers at Dongbeiwang and Quzhou, North China Plain (NCP) in a two-year study. Average concentrations of NH{sub 3}, NO{sub 2}, HNO{sub 3}, pNH{sub 4}{sup +} and pNO{sub 3}{sup -} were 12.0, 12.9, 0.6, 10.3, and 4.7 {mu} g N m{sup -3} across the two sites, showing different seasonal patterns of these N, species. For example, the highest NH{sub 3} concentration occurred in summer while NO{sub 2} concentrations were greater in winter, both of which reflected impacts of N fertilization (summer) and coal-fueled home heating (winter). Based on measured N{sub r} concentrations and their deposition velocities taken from the literature, annual N dry deposition was up to 55 kg N ha{sup -1}. Such high concentrations and deposition rates of N{sub r} species in the NCP indicate very serious air pollution from anthropogenic sources and significant atmospheric N input to crops.

  18. Development and validation of a size-resolved particle dry deposition scheme for applications in aerosol transport models

    Directory of Open Access Journals (Sweden)

    A. Petroff

    2010-08-01

    Full Text Available A size-resolved particle dry deposition scheme is developed, which has been designed for inclusion in large-scale air quality and climate models, where the size distribution and fate of the atmospheric aerosol is of concern. The "resistance" structure is similar to what is proposed by Zhang et al. (2001, 2003, while a new "surface" deposition velocity (or surface resistance is derived by simplification of a one-dimensional aerosol transport model (Petroff et al., 2008b, 2009. Collection efficiencies are given for the 26 Land Use Categories that decribe the earth surface. Validation of this model with existing measurements is performed on desert, grass, coniferous forest and liquid water surfaces. A comparison of this model with measurements on snow and ice is also given. Even though a qualitative agreement is reached, further size-segegated measurements are needed in order to confirm the model accuracy on this surface. The present analytical model provides more accurate predictions of the aerosol deposition on these surfaces than previous models.

  19. Mechanism of carbon deposit/removal in methane dry reforming on supported metal catalysts

    NARCIS (Netherlands)

    Nagaoka, K.; Seshan, K.; Lercher, J.A.; Aika, A.; Iglesia, E.; Spivey, J.J.; Fleisc, T.H.

    2001-01-01

    The greater resistance to coke deposition for Pt/ZrO2 compared to Pt/Al2O3 in the CH4/CO2 reaction has been attributed to the higher reactivity of coke with CO2 on Pt/ZrO2 [1]. Hence, in this communication, the reaction of coke derived from methane (CHx: which is an intermediated in the reforming re

  20. Mechanism of carbon deposit - removal in methane dry reforming on supported metal catalysts

    NARCIS (Netherlands)

    Nagaoka, K.; Nagaoka, K.; Seshan, Kulathuiyer; Lercher, J.A.; Aika, A.; Iglesia, E.; Spivey, J.J.; Fleisc, T.H.

    2001-01-01

    The greater resistance to coke deposition for Pt/ZrO2 compared to Pt/Al2O3 in the CH4/CO2 reaction has been attributed to the higher reactivity of coke with CO2 on Pt/ZrO2 [1]. Hence, in this communication, the reaction of coke derived from methane (CHx: which is an intermediated in the reforming re

  1. A multipoint (49 points) study of dry deposition of polycyclic aromatic hydrocarbons (PAHs) in Erzurum, Turkey by using surrogated snow surface samplers.

    Science.gov (United States)

    Bayraktar, Hanefi; Paloluoğlu, Cihan; Turalioğlu, Fatma S; Gaga, Eftade O

    2016-06-01

    Dry deposition of atmospheric 18 polycyclic aromatic hydrocarbon (PAH) components was investigated in the scope of the study by using surrogate snow samplers at 49 different sampling points in and around the city center of Erzurum, Turkey. Snow was sampled twice, the first of which was taken immediately after the first fresh snow cover and placed into aluminum trays to obtain dry deposition surface while the second sample was taken from the snow cover (accumulated snow) exposed to an 8-day dry deposition period and then analyzed and extracted. All the samples taken from the samplers were extracted using solid and liquid phase extraction and analyzed through GC-MS. It was observed that at the end of an 8-day dry period, snow samples enriched 5.5 times more in PAH components than the baseline. PAH deposition was determined to be influenced mainly by coal, mixed source, traffic, diesel fuel, and petrol fuel at 43, 27, 20, 8, and 2 % of sampling points, respectively. Local polluting sources were found to be effective on the spatial distribution of dry deposition of PAH components in urban area.

  2. Partitioning and granulometric distribution of metal leachate from urban traffic dry deposition particulate matter subject to acidic rainfall and runoff retention.

    Science.gov (United States)

    Sansalone, J; Ying, G

    2008-09-01

    Vehicular transportation coupled with urban hydrology is a significant source as well as vector of particulate matter (PM) and particulate-bound metal inventories in urban systems. This study examines the granulometric distribution of metals from dry deposition PM generated from 17 dryfall periods and equilibrium metal partitioning with runoff PM distribution from eight rainfall-runoff events at an urban inter-state watershed in Baton Rouge, LA. Dry deposition PM is a coarse non-uniform gradation with a d(50 m)=304 microm and a peak surface area at 106 microm. Results indicate acid rain is not a significant metal contributor to runoff but is capable of leaching metals from PM to runoff. Retained runoff partitioning resulted in particulate-bound predominance for As, Cd, Cr, Cu, Pb, and Zn while Ca and Mg remained predominately dissolved. The finer PM fraction (75 microm). This coarse fraction is also the most labile when exposed to acidic rainfall; generating up to 90% of the total metal mass leached from the entire PM gradation. Comparing dry deposition and runoff PM of equal mass and size gradation, retained runoff PM is enriched with metals (except Pb). Results indicate the labile coarse fraction of dry deposition PM can be a significant source of metal leaching while runoff PM (mobilized dry deposition PM) stored in a BMP can be metal-enriched with the potential for re-leaching or scour.

  3. Friction and wear behavior of nitrogen-doped ZnO thin films deposited via MOCVD under dry contact

    Directory of Open Access Journals (Sweden)

    U.S. Mbamara

    2016-06-01

    Full Text Available Most researches on doped ZnO thin films are tilted toward their applications in optoelectronics and semiconductor devices. Research on their tribological properties is still unfolding. In this work, nitrogen-doped ZnO thin films were deposited on 304 L stainless steel substrate from a combination of zinc acetate and ammonium acetate precursor by MOCVD technique. Compositional and structural studies of the films were done using Rutherford Backscattering Spectroscopy (RBS and X-ray Diffraction (XRD. The frictional behavior of the thin film coatings was evaluated using a ball-on-flat configuration in reciprocating sliding under dry contact condition. After friction test, the flat and ball counter-face surfaces were examined to assess the wear dimension and failure mechanism. Both friction behavior and wear (in the ball counter-face were observed to be dependent on the crystallinity and thickness of the thin film coatings.

  4. Lecithin/TPGS-based spray-dried self-microemulsifying drug delivery systems: In vitro pulmonary deposition and cytotoxicity.

    Science.gov (United States)

    Ishak, Rania A H; Osman, Rihab

    2015-05-15

    The aim of the present work was to develop a new solid self-microemulsifying drug delivery system (SMEDDS) for the pulmonary delivery of the poorly water-soluble anti-cancer drug atorvastatin (AVT). Microemulsion (ME) was first developed using isopropyl myristate (IPM), a combination of 2 biocompatible surfactants: lecithin/d-α-tocopheryl polyethylene glycol succinate (TPGS) and ethanol as co-surfactant. Two types of lecithin with different phosphatidylcholine (PC) contents were compared. Phase diagram, physico-chemical characterization and stability studies were used to investigate ME region. Solid SMEDDS were then prepared by spray-drying the selected ME using a combination of carriers composed of sugars, leucine as dispersibility enhancer with or without polyethylene glycol (PEG) 6000. Yield, flow properties, particle size and in vitro pulmonary deposition were used to characterize the spray-dried powders. Reconstituted MEs were characterized in terms of morphology, particle size and size distribution. In vitro cytotoxicity study was undertaken on lung cancer cell line for the selected MEs and SD-SMEDDS formulae. Results showed that the most satisfactory MEs properties were obtained with 1:3 lecithin/TPGS, 1:1 lecithin/oil and 1:1 surfactant/co-surfactant ratios. A larger ME area was obtained with lecithin containing 100% PC compared to the less expensive lecithin containing 20% PC. By manipulating spray drying parameters, carrier composition and ratio of ME lipids to carrier, microparticles with more than 70% of respirable fraction could be prepared. The ME was efficiently recovered in simulated lung fluid even after removal of alcohol. The concurrent delivery of AVT with TPGS in solid SMEDDS greatly enhanced the cytotoxic activity on lung cancer cells. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Spreading and Deposit Characteristics of a Rapid Dry Granular Avalanche Across 3D Topography: Experimental Study

    Science.gov (United States)

    Wang, Yu-Feng; Xu, Qiang; Cheng, Qian-Gong; Li, Yan; Luo, Zhong-Xu

    2016-11-01

    Aiming to understand the propagation and deposit behaviours of a granular avalanche along a 3D complex basal terrain, a new 3D experimental platform in 1/400 scale was developed according to the natural terrain of the Xiejiadianzi rock avalanche, with a series of laboratory experiments being conducted. Through the conduction of these tests, parameters, including the morphological evolution of sliding mass, run-outs and velocities of surficial particles, thickness contour and centre of final deposit, equivalent frictional coefficient, and energy dissipation, are documented and analysed, with the geomorphic control effect, material grain size effect, drop angle effect, and drop distance effect on rock avalanche mobility being discussed primarily. From the study, some interesting conclusions for a better understanding of rock avalanche along a 3D complex basal topography are reached. (1) For the granular avalanche tested in this study, great differences between the evolutions of the debris along the right and left branch valleys were observed, with an obvious geomorphic control effect on avalanche mobility presented. In addition, some other interesting features, including groove-like trough and superelevation, were also observed under the control of the topographic interferences. (2) The equivalent frictional coefficients of the granular avalanches tested here range from 0.48 to 0.57, which is lower than that reached with a set-up composed of an inclined chute and horizontal plate and higher than that reached using a set-up composed of only an inclined chute. And the higher the drop angle and fine particle content, the higher the equivalent frictional coefficient. The effect of drop distance on avalanche mobility is minor. (3) For a granular avalanche, momentum transfer plays an important role in the motion of mass, which can accelerate the mobility of the front part greatly through delivering the kinetic energy of the rear part to the front.

  6. Dry-deposition measurements of sulfur dioxide to a spruce-fir forest in the Black Forest: a data report. Technical memo

    Energy Technology Data Exchange (ETDEWEB)

    McMillen, R.T.; Matt, D.R.; Hicks, B.B.; Womack, J.D.

    1987-02-01

    Measurements of dry deposition of SO/sub 2/ are reported for a forested site in the Black Forest of West Germany. The measurements were made using the eddy-correlation method about 10 meters above the top of a spruce forest that was already affected by Waldsterben. These measurements were conducted as one component of TULLA, a large sulfur mass-balance experiment. The dry-deposition measurements were successful during times when SO/sub 2/ concentrations were greater than 5 micro grams/cu m.

  7. ADVECTION - DIFFUSION NUMERICAL MODEL OF AN AIR POLLUTANT EMITTED FROM AN AREA SOURCE OF PRIMARY POLLUTANT WITH CHEMICAL REACTION AND DRY DEPOSITION

    Directory of Open Access Journals (Sweden)

    SUDHEER PAI K L

    2012-01-01

    Full Text Available A time dependent two dimensional advection-diffusion numerical model for primary pollutant with chemical reaction and dry deposition for an urban area is presented. The proposed numerical model takes into account of realistic form of variable wind velocity and eddy diffusivity profiles. The partial differential equation of primarypollutant is solved by using Crank-Nicolson implicit finite difference technique. The results are plotted for concentration of primary pollutant and the effect of chemical reaction and dry deposition on the dispersion of pollutant are analysed extensively.

  8. Deposition of nanostructured YSZ coating from spray-dried particles with no heat treatment

    Science.gov (United States)

    Zhao, Yan; Gao, Yang

    2015-08-01

    Ytrria stabilized zirconia (YSZ) nanoparticle agglomerates were fabricated by a spray dry method and were directly sprayed using atmospheric plasma spraying (APS) with a current of 300 A and 500 A. A commercially supplied nanostructured YSZ powder (sintered) was also sprayed under the same conditions for comparison. A scanning electron microscope (SEM), an optical microscope (OM) and X-ray diffraction (XRD) were utilized to characterize the feedstock powder and coatings. Weibull plots were used to analyze the performance of the nanostructured coatings. The lower 300 A operating current resulted in a higher portion of nanostructure retention at the expense of coating quality. An approximate 10% increase in porosity and a noticeable decrease in grain size (∼104 nm) were obtained by spraying non-heat treated agglomerates with a 500 A current. The thermal conductivity (400-600 °C) was evaluated using the one-dimensional, steady state Fourier's law of heat conduction. Next, lower thermal conductivity (∼1.3 W m-1 K-1 at 600 °C) was identified in coatings engineered at 500 A from agglomerated powder with no heat treatment.

  9. An Artificial Turf-Based Surrogate Surface Collector for the Direct Measurement of Atmospheric Mercury Dry Deposition

    Directory of Open Access Journals (Sweden)

    Naima L. Hall

    2017-02-01

    Full Text Available This paper describes the development of a new artificial turf surrogate surface (ATSS sampler for use in the measurement of mercury (Hg dry deposition. In contrast to many existing surrogate surface designs, the ATSS utilizes a three-dimensional deposition surface that may more closely mimic the physical structure of many natural surfaces than traditional flat surrogate surface designs (water, filter, greased Mylar film. The ATSS has been designed to overcome several complicating factors that can impact the integrity of samples with other direct measurement approaches by providing a passive system which can be deployed for both short and extended periods of time (days to weeks, and is not contaminated by precipitation and/or invalidated by strong winds. Performance characteristics including collocated precision, in-field procedural and laboratory blanks were evaluated. The results of these performance evaluations included a mean collocated precision of 9%, low blanks (0.8 ng, high extraction efficiency (97%–103%, and a quantitative matrix spike recovery (100%.

  10. An Artificial Turf-Based Surrogate Surface Collector for the Direct Measurement of Atmospheric Mercury Dry Deposition

    Science.gov (United States)

    Hall, Naima L.; Dvonch, Joseph Timothy; Marsik, Frank J.; Barres, James A.; Landis, Matthew S.

    2017-01-01

    This paper describes the development of a new artificial turf surrogate surface (ATSS) sampler for use in the measurement of mercury (Hg) dry deposition. In contrast to many existing surrogate surface designs, the ATSS utilizes a three-dimensional deposition surface that may more closely mimic the physical structure of many natural surfaces than traditional flat surrogate surface designs (water, filter, greased Mylar film). The ATSS has been designed to overcome several complicating factors that can impact the integrity of samples with other direct measurement approaches by providing a passive system which can be deployed for both short and extended periods of time (days to weeks), and is not contaminated by precipitation and/or invalidated by strong winds. Performance characteristics including collocated precision, in-field procedural and laboratory blanks were evaluated. The results of these performance evaluations included a mean collocated precision of 9%, low blanks (0.8 ng), high extraction efficiency (97%–103%), and a quantitative matrix spike recovery (100%). PMID:28208603

  11. Effects of texture on salt precipitation dynamics and deposition patterns in drying porous media

    Science.gov (United States)

    Norouzi Rad, Mansoureh; Shokri, Nima

    2015-04-01

    Understanding the physics of water evaporation from saline porous media is important in many natural and engineering applications such as durability of building materials and preservation of monuments, CO2 sequestration and water quality. Also excess of salt accumulation in soil may result in soil salinization which is a global problem adversely affecting vegetation, plant growth and crop production. Thus it is important to understand the parameters affecting salt transport and precipitation in porous media. We applied X-ray micro-tomography to investigate the dynamics of salt precipitation during evaporation from porous media as influenced by the particle and pore sizes. The packed beds were saturated with NaCl solution of 3 Molal and the time-lapse X-ray imaging was continued for one day. The results show that the presence of preferential evaporation sites (associated with fine pores) on the surface of the sand columns influences significantly the patterns and dynamics of NaCl precipitation (Norouzi Rad et al., 2013; Norouzi Rad and Shokri, 2014). They confirm the formation of an increasingly thick and discrete salt crust with increasing grain size in the sand column due to the presence of fewer fine pores (preferential precipitation sites) at the surface compared to the sand packs with finer grains. Fewer fine pores on the surface also results in shorter stage-1 precipitation for the columns with larger grain sizes. A simple model for the evolution of salt crust thickness based on this principle shows a good agreement with our experiments. Our results provide new insights regarding the physics of salt precipitation and its complex dynamics in porous media during evaporation. References Norouzi Rad, M., Shokri, N., Sahimi, M. (2013), Pore-Scale Dynamics of Salt Precipitation in Drying Porous Media, Phys. Rev. E, 88, 032404. Norouzi Rad, M., Shokri, N. (2014), Effects of grain angularity on NaCl precipitation in porous media during evaporation, Water Resour. Res

  12. Boring of full scale deposition holes using a novel dry blind boring method

    Energy Technology Data Exchange (ETDEWEB)

    Autio, J.; Kirkkomaeki, T. [Saanio and Riekkola Oy, Helsinki (Finland)

    1996-10-01

    Three holes the size of deposition holes (depth 7.5 m and diameter 1.5 m) were bored in the Research Tunnel at Olkiluoto, Finland. A novel full-face boring technique was used based on rotary crushing of rock and removal of crushed rock by vacuum flushing through the drill string. The purpose of the work was to demonstrate the feasibility of the technique. During the boring test procedures were carried out in order to determine the effect of changes in operating parameters on the performance of the boring machine and the quality of the hole. The boring method was found to be technically feasible and efficient. Evaluation of the quality of the hole included studies of the geometry of the hole, measurements of the surface roughness using a laser profilometer and study of excavation disturbances in the zone adjacent to the surface of the holes using two novel methods, He-gas diffusion and the {sup 14}C-polymethylmethacrylate methods. 43 refs.

  13. Climate sensitivity of gaseous elemental mercury dry deposition to plants: impacts of temperature, light intensity, and plant species.

    Science.gov (United States)

    Rutter, Andrew P; Schauer, James J; Shafer, Martin M; Creswell, Joel; Olson, Michael R; Clary, Alois; Robinson, Michael; Parman, Andrew M; Katzman, Tanya L

    2011-01-15

    .3-3.7 μg m(-2) of one-sided leaf area; OSLA) when compared to total mercury wet deposition (1.2 μg m(-2) OSLA) and estimates of reactive mercury dry deposition (0.1-6 μg m(-2) OSLA). Resistance-Temperature-Irradiance relationships are provided for use in models.

  14. Mechanistic study of aerosol dry deposition on vegetated canopies; Etude mecaniste du depot sec d'aerosols sur les couverts vegetaux

    Energy Technology Data Exchange (ETDEWEB)

    Petroff, A

    2005-04-15

    The dry deposition of aerosols onto vegetated canopies is modelled through a mechanistic approach. The interaction between aerosols and vegetation is first formulated by using a set of parameters, which are defined at the local scale of one surface. The overall deposition is then deduced at the canopy scale through an up-scaling procedure based on the statistic distribution parameters. This model takes into account the canopy structural and morphological properties, and the main characteristics of the turbulent flow. Deposition mechanisms considered are Brownian diffusion, interception, initial and turbulent impaction, initially with coniferous branches and then with entire canopies of different roughness, such as grass, crop field and forest. (author)

  15. A macroscale mixture theory analysis of deposition and sublimation rates during heat and mass transfer in dry snow

    Directory of Open Access Journals (Sweden)

    A. C. Hansen

    2015-09-01

    Full Text Available The microstructure of a dry alpine snowpack is a dynamic environment where microstructural evolution is driven by seasonal density profiles and weather conditions. Notably, temperature gradients on the order of 10–20 K m−1, or larger, are known to produce a faceted snow microstructure exhibiting little strength. However, while strong temperature gradients are widely accepted as the primary driver for kinetic growth, they do not fully account for the range of experimental observations. An additional factor influencing snow metamorphism is believed to be the rate of mass transfer at the macroscale. We develop a mixture theory capable of predicting macroscale deposition and/or sublimation in a snow cover under temperature gradient conditions. Temperature gradients and mass exchange are tracked over periods ranging from 1 to 10 days. Interesting heat and mass transfer behavior is observed near the ground, near the surface, as well as immediately above and below dense ice crusts. Information about deposition (condensation and sublimation rates may help explain snow metamorphism phenomena that cannot be accounted for by temperature gradients alone. The macroscale heat and mass transfer analysis requires accurate representations of the effective thermal conductivity and the effective mass diffusion coefficient for snow. We develop analytical models for these parameters based on first principles at the microscale. The expressions derived contain no empirical adjustments, and further, provide self consistent values for effective thermal conductivity and the effective diffusion coefficient for the limiting cases of air and solid ice. The predicted values for these macroscale material parameters are also in excellent agreement with numerical results based on microscale finite element analyses of representative volume elements generated from X-ray tomography.

  16. Simulating Dry Deposition Fluxes of PM10 and Particulate Inorganic Nitrogen over the Eastern China Seas During a Severe Asian Dust Event Using WRF-Chem Model

    Institute of Scientific and Technical Information of China (English)

    YAN Han; GAO Huiwang; YAO Xiaohong; WANG Zifa

    2012-01-01

    A WRF-Chem model including a comprehensive gas-phase nitrogen chemistry module was used to simulate a severe dust event appearing in the eastern China on 19-25 March,2002.The modeling result well reproduced PM10 concentrations in various distances from the dust sources and the transport pathway of the dust strom.The results showed that both the concentrations and the dry deposition fluxes of PM10 increased over the China seas during the dust event following the passage of a cold front system.The maximum fluxes of PM10 in the Yellow Sea and the East China Sea during the dust event were 5.5 and 8.4 times of those before the event,respectively.However,the temporal variations of the dry deposition fluxes of particulate inorganic nitrogen differed over the Yellow Sea from those over the East China Sea.Nitrate and ammonium in the whole northern China rapidly decreased because of the intrusion of dust-loaded air on 19 March.The dust plume arrived in the Yellow Sea on 20 March,decreasing the particulate inorganic nitrogen in mass concentration accordingly.The minimum dry deposition fluxes of nitrate and ammonium in the Yellow Sea were about 3/5 and 1/6 of those before the dust arrival,respectively.In contrast,when the dust plume crossed over the Yangtze Delta area,it became abundant in nitrate and ammonium and increased the concentrations and dry deposition fluxes of particulate inorganic nitrogen over the East China Sea,where the maximum dry deposition fluxes of nitrate and ammonium increased approximately by 4.1 and 2.6 times of those prior to the dust arrival.

  17. Comparison of Mercury Mass Loading in Streams to Wet and Dry Atmospheric Deposition in Watersheds of the Western US: Evidence for Non-Atmospheric Mercury Sources

    Science.gov (United States)

    Domagalski, J. L.; Majewski, M. S.; Alpers, C. N.; Eckley, C.

    2015-12-01

    Many streams in the western United States (US) are listed as impaired by mercury (Hg), and it is important to understand the magnitudes of the various sources in order to implement management strategies. Atmospheric deposition of Hg and can be a major source of aquatic contamination, along with mine wastes, and other sources. Prior studies in the eastern US have shown that streams deliver less than 50% of the atmospherically deposited Hg on an annual basis. In this study, we compared annual stream Hg loads for 20 watersheds in the western US to measured wet and modeled dry deposition. Land use varies from undisturbed to mixed (agricultural, urban, forested, mining). Data from the Mercury Deposition Network was used to estimate Hg input from precipitation. Dry deposition was not directly measured, but can be modeled using the Community Multi-scale Air Quality model. At an undeveloped watershed in the Rocky Mountains, the ratio of stream Hg load to atmospheric deposition was 0.2 during a year of average precipitation. In contrast, at the Carson River in Nevada, with known Hg contamination from historical silver mining with Hg amalgamation, stream export exceeded atmospheric deposition by a factor of 60, and at a small Sierran watershed with gold mining, the ratio was 70. Larger watersheds with mixed land uses, tend to have lower ratios of stream export relative to atmospheric deposition suggesting storage of Hg. The Sacramento River was the largest watershed for which Hg riverine loads were available with an average ratio of stream Hg export to atmospheric deposition of 0.10. Although Hg was used in upstream historical mining operations, the downstream river Hg load is partially mitigated by reservoirs, which trap sediment. This study represents the first compilation of riverine Hg loads in comparison to atmospheric deposition on a regional scale; the approach may be useful in assessing the relative importance of atmospheric and non-atmospheric Hg sources.

  18. 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)

  19. Biotoxicity of Mars soils: 1. Dry deposition of analog soils on microbial colonies and survival under Martian conditions

    Science.gov (United States)

    Schuerger, Andrew C.; Golden, D. C.; Ming, Doug W.

    2012-11-01

    Six Mars analog soils were created to simulate a range of potentially biotoxic geochemistries relevant to the survival of terrestrial microorganisms on Mars, and included basalt-only (non-toxic control), salt, acidic, alkaline, aeolian, and perchlorate rich geochemistries. Experiments were designed to simulate the dry-deposition of Mars soils onto spacecraft surfaces during an active descent landing scenario with propellant engines. Six eubacteria were initially tested for tolerance to desiccation, and the spore-former Bacillus subtilis HA101 and non-spore former Enterococcus faecalis ATCC 29212 were identified to be strongly resistant (HA101) and moderately resistant (29212) to desiccation at 24 °C. Furthermore, tests with B. subtilis and E. faecalis demonstrated that at least 1 mm of Mars analog soil was required to fully attenuate the biocidal effects of a simulated Mars-normal equatorial UV flux. Biotoxicity experiments were conducted under simulated Martian conditions of 6.9 mbar, -10 °C, CO2-enriched anoxic atmosphere, and a simulated equatorial solar spectrum (200-1100 nm) with an optical depth of 0.1. For B. subtilis, the six analog soils were found, in general, to be of low biotoxicity with only the high salt and acidic soils exhibiting the capacity to inactivate a moderate number of spores (<1 log reductions) exposed 7 days to the soils under simulated Martian conditions. In contrast, the overall response of E. faecalis to the analog soils was more dramatic with between two and three orders of magnitude reductions in viable cells for most soils, and between six and seven orders of magnitude reductions observed for the high-salt soil. Results suggest that Mars soils are likely not to be overtly biotoxic to terrestrial microorganisms, and suggest that the soil geochemistries on Mars will not preclude the habitability of the Martian surface.

  20. Dry deposition and canopy uptake in Mediterranean holm-oak forests estimated with a canopy budget model: A focus on N estimations

    Science.gov (United States)

    Aguillaume, L.; Izquieta-Rojano, S.; García-Gómez, H.; Elustondo, D.; Santamaría, J. M.; Alonso, R.; Avila, A.

    2017-03-01

    Bulk/wet and throughfall fluxes of major compounds were measured from June 2011 to June 2013 at four Mediterranean holm-oak (Quercus ilex) forests in the Iberian Peninsula. Regression analysis between net throughfall fluxes and precipitation indicated that the best defined canopy process was leaching for K+ and uptake for NH4+ at all sites. A more variable response between sites was found for Na+, Ca2+, SO42- and Cl-, which suggests that the interplay of dry deposition, leaching and uptake at the canopy was different depending on site climate and air quality characteristics. A canopy budget model (CBM) was used to try to discriminate between the canopy processes and enable to estimate dry deposition and uptake fluxes at three of the sites that complied with the model specifications. To derive N uptake, an efficiency factor of NH4+vs. NO3- uptake (xNH4) corresponding to moles of NH4+ taken up for each NO3- mol, has to be determined. Up to now, a value of 6 has been proposed for temperate forests, but we lack information for Mediterranean forests. Experimental determination of N absorption on Quercus ilex seedlings in Spain suggests efficiency factors from 1 to 6. Based on these values, a sensitivity analysis for xNH4 was performed and the NH4sbnd N and NO3sbnd N modeled dry deposition was compared with dry deposition estimated with independent methods (inferential modeling and washing of branches). At two sites in NE Spain under a milder Mediterranean climate, the best match was obtained for xNH4 = 6, corroborating results from European temperate forests. Based on this value, total DIN deposition was 12-13 kg N ha-1 y-1 at these sites. However, for a site in central Spain under drier conditions, variation of the NH4+ efficiency factor had little effect on DD estimates (which ranged from 2 to 2.6 kg N ha-1 y-1 with varying xNH4); when added to wet deposition, this produced a total N deposition in the range 2.6-3.4 kg N ha-1 y-1. Dry deposition was the predominant

  1. Synthesis and Electrochemical Evaluation of Carbon Supported Pt-Co Bimetallic Catalysts Prepared by Electroless Deposition and Modified Charge Enhanced Dry Impregnation

    OpenAIRE

    John Meynard M. Tengco; Bahareh Alsadat Tavakoli Mehrabadi; Yunya Zhang; Akkarat Wongkaew; John R. Regalbuto; Weidner, John W.; John R. Monnier

    2016-01-01

    Carbon-supported bimetallic Pt-Co cathode catalysts have been previously identified as higher activity alternatives to conventional Pt/C catalysts for fuel cells. In this work, a series of Pt-Co/C catalysts were synthesized using electroless deposition (ED) of Pt on a Co/C catalyst prepared by modified charge enhanced dry impregnation. X-ray diffraction (XRD) and scanning transmission electron microscopy (STEM) characterization of the base catalyst showed highly dispersed particles. A basic E...

  2. Parallel measurements of organic and elemental carbon dry (PM1, PM2.5) and wet (rain, snow, mixed) deposition into the Baltic Sea.

    Science.gov (United States)

    Witkowska, Agnieszka; Lewandowska, Anita; Falkowska, Lucyna M

    2016-03-15

    Parallel studies on organic and elemental carbon in PM1 and PM2.5 aerosols and in wet deposition in various forms of its occurrence were conducted in the urbanised coastal zone of the Baltic Sea. The carbon load introduced into the sea water was mainly affected by the form of precipitation. Dry deposition load of carbon was on average a few orders of magnitude smaller than wet deposition. The suspended organic carbon was more effectively removed from the air with rain than snow, while an inverse relationship was found for elemental carbon. However the highest flux of water insoluble organic carbon was recorded in precipitation of a mixed nature. The atmospheric cleaning of highly dissolved organic carbon was observed to be the most effective on the first day of precipitation, while the hydrophobic elemental carbon was removed more efficiently when the precipitation lasted longer than a day.

  3. Microbial ecology of á-Proteobacteria ammonia-oxidizers along a concentration gradient of dry atmospheric nitrogen deposition in the San Bernadino Mountain Range.

    Science.gov (United States)

    Jordan, F. L.; Fenn, M. E.; Stein, L. Y.

    2002-12-01

    The fate of atmospherically-deposited nitrogen from industrial pollution is of major concern in the montane ecosystems bordering the South Coast California Air Basin. Nitrogen deposition rates in the more exposed regions of the San Bernardino Mountains (SBM) are among the highest in North America often exceeding 40 kg ha-1 year-1 in throughfall deposition of nitrate and ammonium (Fenn and Poth, 1999). Forest ecosystems with elevated N deposition generally exhibit elevated accumulation of soil nitrate, leaching and runoff, elevated emissions of nitrogenous gases, increased nitrification, and decreased litter decomposition rates. The role of nitrifying microbial populations, especially those taxonomically associated with the beta-Proteobacteria ammonia-oxidizers (AOB), will provide insight into nitrogen-cycling in these extremely N-saturated environments. Using 16S ribosomal DNA-based molecular techniques (16S rDNA clone library construction and Restriction Fragment Length Polymorphism), we are comparing AOB community diversity at 3 different locations along a natural atmospheric N-deposition concentration gradient in the SBM: from high at Camp Paviaka (CP), medium at Strawberry Peak (SP) to low at Dogwood (DW). As observed for wet N-deposition systems on the east coast, we hypothesized a negative correlation between AOB community diversity, abundance and function with nitrogen loading in the dry N deposition system of SBM. Nitrification potentials determined for the 3 sites along the N-deposition gradient were in the order of CP less than SP less than DW. Preliminary results indicate no correlation between diversity of AOB and increased nitrogen loading. Shannon-Weiner diversity indices calculated for ammonia-oxidizer RFLP group units were 2.22, 2.66 and 1.80 for CP, SP and DW, respectively.

  4. Climate-driven exceedance of total (wet + dry) nitrogen (N) + sulfur (S) deposition to forest soil over the conterminous U.S

    Science.gov (United States)

    Sun, Jian; Fu, Joshua S.; Lynch, Jason A.; Huang, Kan; Gao, Yang

    2017-06-01

    Nitrogen (N) and sulfur (S) depositions are much mitigated over the conterminous U.S. (CONUS) but deposition exceedance still exists on forest soil. In addition, the empirical approach is usually used but only provides a spatially constant critical load (CL). Therefore, the CL derived from steady-state mass balance equation is used to study the CL exceedance on forest soil over the CONUS. The multimodel mean (MMM) of global climate-chemistry models in 2000s indicates that total (wet + dry) N deposition alone over 10.32% of forest soil exceeds the CL, but a higher percent (30.16%) is observed by the N + S deposition, which highlights the necessity of considering S deposition. In 2050s, less CL-exceeded forest soil is projected and the exceedance amount is lower as well, mainly attributed to the strong reduction of projected NOX and SO2 emissions. By first projecting the future CL due to the climate change, the CL exceedance could further decrease as the air temperature is projected to increase rapidly and lead to higher CL in the future. The CL exceedance by N deposition alone is likely to be dominated by NOy in 2000s but NHX in 2050s because of the enhanced NH3 emission. Moreover, both in 2000s and 2050s, using the CL generated by different aggregation methods can cause up to 33 times difference between the corresponding CL exceedance. This suggests that several regions are under the marginal threat of either N or N + S deposition and different CL can influence the results significantly.

  5. Assessment of mobility and bio-availability of heavy metals in dry depositions of Asian dust and implications for environmental risk.

    Science.gov (United States)

    Lee, Pyeong-Koo; Choi, Byoung-Young; Kang, Min-Ju

    2015-01-01

    We assess the potential mobility and bio-availability of selected metals (As, Cd, Co, Cr, Cu, Ni, Mo, Pb, S, Zn, and Zr) in the dry depositions of Asian and non-Asian dust from the city of Daejeon, Korea. For this study, we applied Pb isotopes, total extraction and chemical sequential extraction methods to the dry depositions. In addition, microscopic analysis was performed using X-ray diffraction (XRD) and focused ion beam (FIB)-scanning electron microscopy (SEM-EDS). FIB-SEM cross-section observations and Pb isotope data showed a black carbon is an important carrier of associated heavy metals originating from China. A five-step sequential extraction performed on the dry depositions showed that S and Cd are the most abundant elements in the water-soluble and cation-exchangeable fraction. In addition, Zn and Pb appeared predominantly in the carbonate and reducible fractions. On the other hand, Cu, Mo and, to a lesser degree, As were significantly associated with the organic fraction, while Co, Ni, Cr and Zr were bound to the residual fraction. These results showed that S, Cd, Zn and Pb, which were highly concentrated in potentially mobile fractions, have potential environmental risk because potential changes in redox state and pH may remobilize these metals. In addition, the estimated remobilization concentrations of these metals were significant. Thus, this study shows that frequent and careful monitoring of S, Cd, Z, Pb and, to a lesser degree, Cu, Mo and As is very important for assessing environmental risk in Korea. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Monitoring ambient air pollutants and apply Woods' model in the prediction seasonal dry deposition at Chang-Hua (urban) and Kao-Mei (wetland) county, Taiwan.

    Science.gov (United States)

    Fang, Guor-Cheng; Chang, Chia-Ying

    2014-09-01

    The main purpose for this study was to monitor ambient air particles and metallic elements (Mn, Fe, Zn, Cr, Cu and Pb) in total suspended particulate (TSP) concentration and dry deposition. In addition, the calculated/measured dry deposition flux ratios of ambient air particles and metallic elements (Mn, Fe, Zn, Cr, Cu and Pb) were evaluated using Woods' model at urban and wetland areas for the 2009-2010 period. The results indicated that the mean highest concentrations of metallic elements Mn, Fe, Zn, Cr, Cu and Pb in TSP were found in Chang-Hua (urban) sampling site. And as for the two characteristic sampling sites, the Woods' model exhibits better dry deposition of particulates of 18 µm particle size than the rest of the other particle sizes at any sampling site in this study. The average calculated/measured flux ratios for two seasons (summer and fall) by using Woods model at 2.5, 10 and 18 µm particles sizes were also studied. The results indicated that the average calculated/measured flux ratios orders for two seasons of various particles sizes were all displayed as Fe > Mn > Zn > Cu > Cr > Pb > particle. And these calculated/measured flux ratios orders were Fe > Mn > Cu > Zn > Cr > Pb > particle and were Fe > Mn > Zn > Cu > Cr > particle > Pb, during spring and winter seasons, respectively. Finally, in the spring and summer seasons of Gao-Mei (wetland) sampling site, the average calculated/measured flux ratios using Woods' model was found to be 2.5, 10 and 18 µm, showing the order of the calculated/measured flux ratios to be Fe > Cu > Zn > Mn > Cr > Pb > particle. And the calculated/measured flux ratio orders were Fe > Zn > Mn > Cu > Cr > particle > Pb and were Fe > Cu > Zn > Mn > Cr > particle > Pb for fall and winter season, respectively.

  7. Influence of atmospheric dry deposition of inorganic nutrients on phytoplankton biomass in the coastal Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Yadav, K.; Sarma, V.V.S.S.; Rao, D.B.; DileepKumar, M.

    suggests that atmospheric deposition of nutrients enhances phytoplankton biomass in waters along the central east coast of India during the winter monsoon period, in particular, supporting the hypothesis stated above...

  8. Synthesis and Electrochemical Evaluation of Carbon Supported Pt-Co Bimetallic Catalysts Prepared by Electroless Deposition and Modified Charge Enhanced Dry Impregnation

    Directory of Open Access Journals (Sweden)

    John Meynard M. Tengco

    2016-06-01

    Full Text Available Carbon-supported bimetallic Pt-Co cathode catalysts have been previously identified as higher activity alternatives to conventional Pt/C catalysts for fuel cells. In this work, a series of Pt-Co/C catalysts were synthesized using electroless deposition (ED of Pt on a Co/C catalyst prepared by modified charge enhanced dry impregnation. X-ray diffraction (XRD and scanning transmission electron microscopy (STEM characterization of the base catalyst showed highly dispersed particles. A basic ED bath containing PtCl62− as the Pt precursor, dimethylamine borane as reducing agent, and ethylenediamine as stabilizing agent successfully targeted deposition of Pt on Co particles. Simultaneous action of galvanic displacement and ED resulted in Pt-Co alloy formation observed in XRD and energy dispersive X-ray spectroscopy (XEDS mapping. In addition, fast deposition kinetics resulted in hollow shell Pt-Co alloy particles while particles with Pt-rich shell and Co-rich cores formed with controlled Pt deposition. Electrochemical evaluation of the Pt-Co/C catalysts showed lower active surface but much higher mass and surface activities for oxygen reduction reaction compared to a commercial Pt/C fuel cell catalyst.

  9. Atmospheric particle dry deposition of major ions to the South Atlantic coastal area observed at Baía de Todos os Santos, Brazil

    Directory of Open Access Journals (Sweden)

    STELYUS L. MKOMA

    2014-03-01

    Full Text Available The coastal atmosphere adjacent to large urban areas can be strongly affected by the emission of air pollutants, among them, major ions species. In this study, the chemical composition and sources of carboxylates and other water-soluble ions in fine and coarse aerosols as well as estimates of particle dry deposition fluxes were studied at a tropical coastal site affected by an urban environment. The mean concentrations of the total carboxylates were 78 ng m–3 in fine fraction and 81 ng m–3 in coarse fraction of particulate matter (PM. The corresponding values for the total inorganic ions were 2143 ng m–3 and 4880 ng m–3 respectively. Main sources for fine particles were: (i photochemical formation of carboxylic acids in vapor phase and a posterior gas-to-particle conversion onto sea salt particles; (ii emissions from anthropic sources with long range transportation processes; and (iii the interchanging of volatile species among atmospheric phases. In turn, for coarse particles, the predominant sources were: (i gas-phase species and ab/adsorbed onto pre-existing particles afterwards; (ii primary emission of coarse particles from anthropogenic sources; and (iii sea salt spray and/or soil resuspension. Finally, particle dry deposition was a very important mechanism representing air-to-sea fluxes of major species.

  10. Quantifying the dry deposition of reactive nitrogen and sulfur containing species in remote areas using a surrogate surface analysis approach

    Science.gov (United States)

    Raymond, Heather A.; Yi, Seung-Muk; Moumen, Nadjoua; Han, YoungJi; Holsen, Thomas M.

    In this study, the fluxes of gaseous (HNO 3 and SO 2) and particulate (NO 3- and SO 42-) species were measured using two recently developed surrogate surfaces, the water surface sampler (WSS) and the knife-edge surrogate surface (KSS). Sampling was conducted in Potsdam, NY, Solomons, MD, and at a farm in upstate NY intermittently between March 2000 and August 2001. The KSS contained both Nylasorb filters and greased Mylar disks. No statistical difference was found between measured total nitrate and sulfate deposition in side-by-side experiments with two WSSs. Average total nitrate fluxes measured with the WSS and Nylasorb filter on the KSS in Potsdam, Solomons, and at the farm were 3.6, 6.2, 2.9 mg m -2 day -1 and 2.5, 6.7, 2.3 mg m -2 day -1, respectively. Solomons had the highest total nitrate flux probably due to its proximity to large urban industrialized areas including Washington, DC, and Baltimore, MD. Average gaseous HNO 3 fluxes measured with the WSS and Nylasorb filter on the KSS in Potsdam, Solomons, and at the farm (calculated by subtracting the fraction of particles deposited to the Mylar disk from the total deposition to the WSS and Nylasorb filter) were 2.4, 4.9, 1.9 mg m -2 day -1 and 1.3, 5.6, 1.3 mg m -2 day -1, respectively. In Potsdam, total nitrate deposition to the WSS was greater than to the Nylasorb filter whereas in Solomons the opposite was true. This increased flux at Solomons may be because nitrate salts were formed on the surface of the Nylasorb filter by reaction of HNO 3 with previously deposited sea salt aerosols. Average p-NO 3- fluxes to the greased Mylar for the three sampling sites were 1.3, 1.3, and 1.0 mg m -2 day -1. The measured SO 2 deposition velocity to the WSS in Potsdam and Solomons was 2.1 and 1.5 cm s -1, respectively, and agreed well with other studies. The deposition velocity for HNO 3 to the WSS measured in Potsdam (8.1 cm s -1) was greater than to the Nylasorb filter (4.6 cm s -1) whereas in Solomons the opposite

  11. High N, dry: Experimental nitrogen deposition exacerbates native shrub loss and nonnative plant invasion during extreme drought.

    Science.gov (United States)

    Valliere, Justin M; Irvine, Irina C; Santiago, Louis; Allen, Edith B

    2017-03-20

    Hotter, longer, and more frequent global change-type drought events may profoundly impact terrestrial ecosystems by triggering widespread vegetation mortality. However, severe drought is only one component of global change, and ecological effects of drought may be compounded by other drivers, such as anthropogenic nitrogen (N) deposition and nonnative plant invasion. Elevated N deposition, for example, may reduce drought tolerance through increased plant productivity, thereby contributing to drought-induced mortality. High N availability also often favors invasive, nonnative plant species, and the loss of woody vegetation due to drought may create a window of opportunity for these invaders. We investigated the effects of multiple levels of simulated N deposition on a Mediterranean-type shrubland plant community in southern California from 2011 to 2016, a period coinciding with an extreme, multi-year drought in the region. We hypothesized that N addition would increase native shrub productivity, but that this would increase susceptibility to drought and result in increased shrub loss over time. We also predicted that N addition would favor nonnatives, especially annual grasses, leading to higher biomass and cover of these species. Consistent with these hypotheses, we found that high N availability increased native shrub canopy loss and mortality, likely due to the higher productivity and leaf area and reduced water-use efficiency we observed in shrubs subject to N addition. As native shrub cover declined, we also observed a concomitant increase in cover and biomass of nonnative annuals, particularly under high levels of experimental N deposition. Together, these results suggest that the impacts of extended drought on shrubland ecosystems may be more severe under elevated N deposition, potentially contributing to the widespread loss of native woody species and vegetation type-conversion. This article is protected by copyright. All rights reserved.

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

    Science.gov (United States)

    Xie, Yuanyun; Chi, Yunping

    2016-04-01

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

  13. Atmospheric dry deposition of inorganic and organic nitrogen to the Bay of Bengal: Impact of continental outflow

    Digital Repository Service at National Institute of Oceanography (India)

    Srinivas, B.; Sarin, M.M.; Sarma, V.V.S.S.

    of nitrate in coarse continental aerosols. . Atmospheric Environment,, 18: 977-981. Zhang, Q. and Anastasio, C., 2003a. Conversion of Fogwater and Aerosol Organic Nitrogen to Ammonium, Nitrate, and NOx during Exposure to Simulated Sunlight and Ozone.... Chem., vol.127; 2011; 170–179 Atmospheric Deposition of Inorganic and Organic Nitrogen to the Bay of Bengal: Impact of Continental Outflow Bikkina Srinivas 1 , * M. M. Sarin 1 and V.V.S.S. Sarma 2 1 Physical Research Laboratory, Ahmedabad – 380...

  14. Estimation of air to grass -dry and wet deposition rates, velocities, and mass interception factors for iodine for a postulated accidental scenario

    Energy Technology Data Exchange (ETDEWEB)

    Karunakara, N.; Ujwal, P.; Yashodhara, I.; Sudeep Kumara, K. [University Science Instrumentation Centre, Mangalore University (India); Geetha, P.V. [Nuclear Power Corporation of India Limited (India); Dileep, B.N.; Joshi, P.J. [Environmental Survey Laboratory, Kaiga Generating Station (India); Ravi, P.M. [Health Physics Division, Bhabha Atomic Research Centre (India)

    2014-07-01

    Air to grass radionuclide transfer parameters such as dry and wet deposition rates, velocities, and mass interception factors are important basic input parameters for the estimation of radiation dose to the public around a nuclear power plant. We have carried out a study on air to grass transfer of iodine for a postulated emergency situation. A walk-in environmental chamber was designed and fabricated with facilities for exposing the plants grown in pots to controlled levels of radionuclides/stable elements. The temperature, humidity, and airflow inside the environmental chamber can be controlled to required values. The chamber has the facility for generating artificial rainfall. Grass grown in pots was kept inside the environmental chamber. Stable iodine (elemental form) was sublimed and injected into the environmental chamber suddenly to generate known concentration of iodine in the air inside the chamber. This simulated an accidental release of iodine to the environment. The concentration of iodine in the air inside the chamber was monitored continuously by drawing air from the environmental chamber through a bubbling setup (bubbling air through 1% sodium carbonate solution) and the iodine was then separated chemically and the concentration was measured by UV-VIS spectrometry. The concentration of iodine inside the chamber was monitored for every 30 min. The grass was exposed to iodine for 3 h after which the leaves were sampled and analysed for iodine concentration. From the concentration values of iodine in air and grass - the dry deposition rate, deposition velocity, and mass interception rates were estimated. The dry deposition velocity of iodine varied in the range of 0.5x10{sup -5}-3.3x10{sup -5} m s{sup -1} with a mean value of 1.7x10{sup -5} m s{sup -1}. The mass interception factor varied in the range of 0.25-13 m{sup 2} kg{sup -1} with a mean value of 4.2 m{sup 2} kg{sup -1} with respect to fresh weight. The wet deposition velocity varied in the range

  15. Growth, Mineral Deposition, and Physiological Responses of Broiler Chickens Offered Honey in Drinking Water during Hot-Dry Season

    Directory of Open Access Journals (Sweden)

    Monsuru Oladimeji Abioja

    2012-01-01

    Full Text Available Growing broilers were offered either 0 (0H, 10 (10H, 20 mL (20H honey, or 0.5 g vitamin C/litre water (AA during hot-dry season. Honey had no significant (>0.05 effect on feed intake (FI, weight gain (WG, feed conversion ratio (FCR, water intake (WI, survival (SURV, dressed percentage (DRE, breast meat (BRE, gizzard (GIZ, drumstick (DRU, shank (SHA, thigh (THI, tibia volume (VOL, and magnesium (MAG. Effect of honey was significant (0.005. Higher dose of honey lowered PR and HR. Honey significantly (0.05 affected. 20H broilers had higher THY than 0H and 10H groups. In conclusion, honey did not affect growth but might improve broilers’ welfare when offered up to 20H during hot periods.

  16. Direct and Dry Deposited Single-Walled Carbon Nanotube Films Doped with MoO(x) as Electron-Blocking Transparent Electrodes for Flexible Organic Solar Cells.

    Science.gov (United States)

    Jeon, Il; Cui, Kehang; Chiba, Takaaki; Anisimov, Anton; Nasibulin, Albert G; Kauppinen, Esko I; Maruyama, Shigeo; Matsuo, Yutaka

    2015-07-01

    Organic solar cells have been regarded as a promising electrical energy source. Transparent and conductive carbon nanotube film offers an alternative to commonly used ITO in photovoltaics with superior flexibility. This communication reports carbon nanotube-based indium-free organic solar cells and their flexible application. Direct and dry deposited carbon nanotube film doped with MoO(x) functions as an electron-blocking transparent electrode, and its performance is enhanced further by overcoating with PSS. The single-walled carbon nanotube organic solar cell in this work shows a power conversion efficiency of 6.04%. This value is 83% of the leading ITO-based device performance (7.48%). Flexible application shows 3.91% efficiency and is capable of withstanding a severe cyclic flex test.

  17. Radial line-scans as representative sampling strategy in dried-droplet laser ablation of liquid samples deposited on pre-cut filter paper disks

    Energy Technology Data Exchange (ETDEWEB)

    Nischkauer, Winfried [Institute of Chemical Technologies and Analytics, Vienna University of Technology, Vienna (Austria); Department of Analytical Chemistry, Ghent University, Ghent (Belgium); Vanhaecke, Frank [Department of Analytical Chemistry, Ghent University, Ghent (Belgium); Bernacchi, Sébastien; Herwig, Christoph [Institute of Chemical Engineering, Vienna University of Technology, Vienna (Austria); Limbeck, Andreas, E-mail: Andreas.Limbeck@tuwien.ac.at [Institute of Chemical Technologies and Analytics, Vienna University of Technology, Vienna (Austria)

    2014-11-01

    conventional liquid measurements, and by analyzing IAEA-153 reference material (Trace Elements in Milk Powder); a good agreement with the certified value for phosphorus was obtained. - Highlights: • Sample preparation via deposition of liquids on pre-cut filter disks. • Sample introduction via laser ablation of dried filters. • Representative sampling avoids bias. • Signal quantification via external calibration and aqueous standard solutions. • Alternative approach for quantifying P in challenging matrix.

  18. Dry powders based on PLGA nanoparticles for pulmonary delivery of antibiotics: modulation of encapsulation efficiency, release rate and lung deposition pattern by hydrophilic polymers.

    Science.gov (United States)

    Ungaro, Francesca; d'Angelo, Ivana; Coletta, Ciro; d'Emmanuele di Villa Bianca, Roberta; Sorrentino, Raffaella; Perfetto, Brunella; Tufano, Maria Antonietta; Miro, Agnese; La Rotonda, Maria Immacolata; Quaglia, Fabiana

    2012-01-10

    Although few experimental studies have been handled so far to exploit the potential of poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) in the production of dry powders for antibiotic inhalation, there has been no comprehensive study on the role played by NP composition. In this work, we try to shed light on this aspect by designing and developing a pulmonary delivery system for antibiotics, such as tobramycin (Tb), based on PLGA NPs embedded in an inert microcarrier made of lactose, referred to as nano-embedded micro-particles (NEM). At nanosize level, helper hydrophilic polymers were used to impart the desired surface, bulk and release properties to PLGA NPs prepared by a modified emulsion-solvent diffusion technique. Results showed that poly(vinyl alcohol) (PVA) and chitosan (CS) are essential to optimise the size and modulate the surface properties of Tb-loaded PLGA NPs, whereas the use of alginate (Alg) allows efficient Tb entrapment within NPs and its release up to one month. Optimized formulations display good in vitro antimicrobial activity against P. aeruginosa planktonic cells. Furthermore, spray-drying of the NPs with lactose yielded NEM with peculiar but promising flow and aerosolization properties, while preserving the peculiar NP features. Nonetheless, in vivo biodistribution studies showed that PVA-modified Alg/PLGA NPs reached the deep lung, while CS-modified NPs were found in great amounts in the upper airways, lining lung epithelial surfaces. In conclusion, PLGA NP composition appears to play a crucial role in determining not only the technological features of NPs but, once processed in the form of NEM, also their in vitro/in vivo deposition pattern.

  19. Chemistry, transport and dry deposition of trace gases in the boundary layer over the tropical Atlantic Ocean and the Guyanas during the GABRIEL field campaign

    Directory of Open Access Journals (Sweden)

    A. Stickler

    2007-07-01

    Full Text Available We present a comparison of different Lagrangian and chemical box model calculations with measurement data obtained during the GABRIEL campaign over the tropical Atlantic Ocean and the Amazon rainforest in the Guyanas, October 2005. Lagrangian modelling of boundary layer (BL air constrained by measurements is used to derive a horizontal gradient (≈5.6 pmol/mol km−1 of CO from the ocean to the rainforest (east to west. This is significantly smaller than that derived from the measurements (16–48 pmol/mol km−1, indicating that photochemical production from organic precursors alone cannot explain the observed strong gradient. It appears that HCHO is overestimated by the Lagrangian and chemical box models, which include dry deposition but not exchange with the free troposphere (FT. The relatively short lifetime of HCHO implies substantial BL-FT exchange. The mixing-in of FT air affected by African and South American biomass burning at an estimated rate of 0.12 h−1 increases the CO and decreases the HCHO mixing ratios, improving agreement with measurements. A mean deposition velocity of 1.35 cm/s for H2O2 over the ocean as well as over the rainforest is deduced assuming BL-FT exchange adequate to the results for CO. The measured increase of the organic peroxides from the ocean to the rainforest (≈0.66 nmol/mol d−1 is significantly overestimated by the Lagrangian model, even when using high values for the deposition velocity and the entrainment rate. Our results point at either heterogeneous loss of organic peroxides and/or their radical precursors, underestimated photodissociation or missing reaction paths of peroxy radicals not forming peroxides in isoprene chemistry. We calculate a mean integrated daytime net ozone production (NOP in the BL of (0.2±5.9 nmol/mol (ocean and (2.4±2.1 nmol/mol (rainforest. The NOP strongly correlates with NO and has a positive tendency in

  20. Extrinsic lactose fines improve dry powder inhaler formulation performance of a cohesive batch of budesonide via agglomerate formation and consequential co-deposition.

    Science.gov (United States)

    Kinnunen, Hanne; Hebbink, Gerald; Peters, Harry; Huck, Deborah; Makein, Lisa; Price, Robert

    2015-01-15

    The aim of the study was to investigate how the fine particle content of lactose carriers prepared with different types of lactose fines regulates dry powder inhaler (DPI) formulation performance of a cohesive batch of micronised budesonide. Budesonide formulations (0.8 wt%) were prepared with three different lactose carriers (Lactohale (LH) LH100, 20 wt% LH210 in LH100 and 20 wt% LH300 in LH100). Fine particle fraction of emitted dose (FPFED) and mean mass aerodynamic diameter (MMAD) of budesonide was assessed with a Next Generation Impactor (NGI) using a Cyclohaler at 90 l/min. Morphological and chemical characteristics of particles deposited on Stage 2 were determined using a Malvern Morphologi G3-ID. The results indicate that increasing concentration of lactose fines (lactose particles were available the more agglomerates of budesonide and lactose were delivered to Stage 2. These results suggest drug-fines agglomerate formation is an important mechanism for how lactose fines improve and regulate DPI formulation performance.

  1. Dry Eye

    Science.gov (United States)

    ... Eye > Facts About Dry Eye Facts About Dry Eye This information was developed by the National Eye ... the best person to answer specific questions. Dry Eye Defined What is dry eye? Dry eye occurs ...

  2. Influences of land use and antecedent dry-weather period on pollution level and ecological risk of heavy metals in road-deposited sediment.

    Science.gov (United States)

    Zhang, Jin; Hua, Pei; Krebs, Peter

    2017-09-01

    Road-deposited sediment and its adsorbed pollutants have been regarded as significant sources of urban diffuse pollution. In this study, the solid-phase concentrations (mg/g), surface load (mg/m(2)) and chemical fractionation of zinc (Zn), copper (Cu) and cadmium (Cd) were determined. Geo-accumulation (Igeo) and ecological risk (RI) indexes were employed for metal risk assessment. Results show that the highest solid-phase concentrations of Zn and Cu were usually found at an industrial area. However, Cd had the highest solid-phase concentrations at a rural area, followed by a commercial area. The surface loads of Zn and Cu decreased along the city centre to city border gradient. However, Cd was distributed irregularly. In terms of chemical fractionation, the predominant components of Zn and Cd were identified in the unstable exchangeable fractions, indicating high potential ecological risks to the aquatic environments. Cu posed a comparably low risk due to the high proportions of the stable components of residual and oxidisable fractions. According to a two-dimensional hierarchical cluster analysis, Zn and Cu surface loads were dominantly influenced by the antecedent dry-weather period; Cd contents were strongly land-use type dependent. In addition, the enrichment capability was ranked as Zn > Cu > Cd determined by Igeo index. The sampling site dependent potential ecological risk was determined as rural area (R) > commercial city centre (W) > federal highway (B) > industrial area (I) > main road (S) > secondary road (A) by the RI index. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Fluid flow in drying drops

    NARCIS (Netherlands)

    Gelderblom, H.

    2013-01-01

    When a suspension drop evaporates, it leaves behind a drying stain. Examples of these drying stains encountered in daily life are coffee or tea stains on a table top, mineral rings on glassware that comes out of the dishwasher, or the salt deposits on the streets in winter. Drying stains are also pr

  4. 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

  5. Dry and Wet Atmospheric Deposition of Nitrogen into Shaoguan, Guangdong Province%广东韶关地区大气氮干湿沉降特征研究

    Institute of Scientific and Technical Information of China (English)

    刘思言; 陈瑾; 卢平; 李来胜; 陈中颖

    2014-01-01

    2012年4月─2013年9月利用自动分离干湿沉降的采样器对广东省韶关市降雨和干沉降进行采集,分析样品降雨量、降尘量及氮营养盐干湿沉降浓度,计算各指标干湿沉降通量,利用沉降通量分析其影响因素及季节性变化趋势,为该地区大气氮沉降的通量预测及其环境管理提供支持,并为其生态环境中污染物的控制与减排提供科学依据。结果表明,观测期间总氮干沉降通量、湿沉降通量和总沉降通量平均值分别为47.73、295.7和310.5 kg·km-2·month-1。氨态氮、硝酸盐氮与有机氮干沉降通量平均值分别为17.39、12.98和17.37 kg·km-2·month-1,其湿沉降通量平均值分别为132.4、117.0和46.23 kg·km-2·month-1。总氮湿沉降通量占总氮总沉降通量平均比例为83.19%,说明总氮沉降通量以湿沉降为主。影响因素方面,总氮干沉降通量与降尘量无相关性;湿沉降受降雨量影响较大,所以受雨季影响,韶关地区4─6月总氮湿沉降负荷较大。成分组成上,干沉降中氨态氮平均占总氮比例35.48%,硝酸盐氮平均占27.96%,有机氮平均占36.55%,因此该地区氮营养盐干沉降中以氨态氮和有机氮为主;氮营养盐湿沉降以氨态氮和硝酸盐氮为主,氨态氮平均占总氮比例46.87%,硝酸盐氮平均占40.64%,有机氮平均比例为12.49%,说明该地区湿沉降同时受到农业活动和工业活动的影响。季节变化上,氮营养盐干沉降通量由大到小依次为冬季、春季、秋季、夏季,湿沉降通量春季较高,夏秋两季较低。%To help predicate the atmospheric nitrogen deposition fluxes and provide scientific basises for ecological environment pollution control and abatement assist environmental, the characteristics of atmospheric nitrogen deposition in Shaoguan, Guangdong Province were investigated. In the study, the dry and wet atmospheric nitrogen deposition samples

  6. Dielectric properties of Al2O3 coatings deposited via atmospheric plasma spraying and dry-ice blasting correlated with microstructural characteristics

    Science.gov (United States)

    Dong, Shujuan; Song, Bo; Liao, Hanlin; Coddet, Christian

    2015-01-01

    In this work, atmospheric plasma spraying combined with dry-ice blasting have been used to prepare alumina (Al2O3) coatings designed for insulating applications. The microstructural characteristics and dielectric properties of Al2O3 coatings were presented. The electrical insulating properties, i.e., dielectric strength and breakdown voltage, were investigated by dielectric breakdown test using direct current and alternating current. Relationships between dielectric properties and coating characteristics were discussed. The results showed that dry-ice blasting used during atmospheric plasma spray process allowed the production of coatings with better dielectric properties than those prepared without dry-ice blasting. The dielectric properties were correlated with the microstructural characteristics, not with phase composition.

  7. Radial line-scans as representative sampling strategy in dried-droplet laser ablation of liquid samples deposited on pre-cut filter paper disks

    Science.gov (United States)

    Nischkauer, Winfried; Vanhaecke, Frank; Bernacchi, Sébastien; Herwig, Christoph; Limbeck, Andreas

    2014-11-01

    Nebulising liquid samples and using the aerosol thus obtained for further analysis is the standard method in many current analytical techniques, also with inductively coupled plasma (ICP)-based devices. With such a set-up, quantification via external calibration is usually straightforward for samples with aqueous or close-to-aqueous matrix composition. However, there is a variety of more complex samples. Such samples can be found in medical, biological, technological and industrial contexts and can range from body fluids, like blood or urine, to fuel additives or fermentation broths. Specialized nebulizer systems or careful digestion and dilution are required to tackle such demanding sample matrices. One alternative approach is to convert the liquid into a dried solid and to use laser ablation for sample introduction. Up to now, this approach required the application of internal standards or matrix-adjusted calibration due to matrix effects. In this contribution, we show a way to circumvent these matrix effects while using simple external calibration for quantification. The principle of representative sampling that we propose uses radial line-scans across the dried residue. This compensates for centro-symmetric inhomogeneities typically observed in dried spots. The effectiveness of the proposed sampling strategy is exemplified via the determination of phosphorus in biochemical fermentation media. However, the universal viability of the presented measurement protocol is postulated. Detection limits using laser ablation-ICP-optical emission spectrometry were in the order of 40 μg mL- 1 with a reproducibility of 10 % relative standard deviation (n = 4, concentration = 10 times the quantification limit). The reported sensitivity is fit-for-purpose in the biochemical context described here, but could be improved using ICP-mass spectrometry, if future analytical tasks would require it. Trueness of the proposed method was investigated by cross-validation with

  8. Influence of the diameter of single-walled carbon nanotube bundles on the optoelectronic performance of dry-deposited thin films

    Directory of Open Access Journals (Sweden)

    Kimmo Mustonen

    2012-10-01

    Full Text Available The optoelectronic performance of thin films of single-walled carbon nanotubes (SWCNTs was studied with respect to the properties of both individual nanotubes and their bundles. The SWCNTs were synthesized in a hot wire generator aerosol reactor, collected by gas filtration and dry-transferred onto various substrates. By thus completely avoiding liquid dispersion steps, we were able to avoid any artifacts from residual surfactants or sonication. We found that bundle lengths determined the thin-film performance, as would be expected for highly resistive bundle–bundle junctions. However, we found no evidence that contact resistances were affected by the bundle diameters, although they did play a secondary role by simply affecting the absorption. The individual SWCNT diameters and their graphitization level as gauged by the Raman D band intensity did not show any clear correlation with the overall performance.

  9. Influence of the diameter of single-walled carbon nanotube bundles on the optoelectronic performance of dry-deposited thin films.

    Science.gov (United States)

    Mustonen, Kimmo; Susi, Toma; Kaskela, Antti; Laiho, Patrik; Tian, Ying; Nasibulin, Albert G; Kauppinen, Esko I

    2012-01-01

    The optoelectronic performance of thin films of single-walled carbon nanotubes (SWCNTs) was studied with respect to the properties of both individual nanotubes and their bundles. The SWCNTs were synthesized in a hot wire generator aerosol reactor, collected by gas filtration and dry-transferred onto various substrates. By thus completely avoiding liquid dispersion steps, we were able to avoid any artifacts from residual surfactants or sonication. We found that bundle lengths determined the thin-film performance, as would be expected for highly resistive bundle-bundle junctions. However, we found no evidence that contact resistances were affected by the bundle diameters, although they did play a secondary role by simply affecting the absorption. The individual SWCNT diameters and their graphitization level as gauged by the Raman D band intensity did not show any clear correlation with the overall performance.

  10. Spatially Modeling the Impact of Terrain on Wind Speed and Dry Particle Deposition Across Lake Perris in Southern California to Determine In Situ Sensor Placement

    Science.gov (United States)

    Brooks, A. N.

    2014-12-01

    While developed countries have implemented engineering techniques and sanitation technologies to keep water resources clean from runoff and ground contamination, air pollution and its contribution of harmful contaminants to our water resources has yet to be fully understood and managed. Due to the large spatial and temporal extent and subsequent computational intensity required to understand atmospheric deposition as a pollutant source, a geographic information system (GIS) was utilized. This project developed a multi-step workflow to better define the placement of in situ sensors on Lake Perris in Southern California. Utilizing a variety of technologies including ArcGIS 10.1 with 3D and Spatial Analyst extensions and WindNinja, the impact of terrain on wind speed and direction was simulated and the spatial distribution of contaminant deposition across Lake Perris was calculated as flux. Specifically, the flux of particulate matter (PM10) at the air - water interface of a lake surface was quantified by season for the year of 2009. Integrated Surface Hourly (ISH) wind speed and direction data and ground station air quality measurements from the California Air Resources Board were processed and integrated for use within ModelBuilder. Results indicate that surface areas nearest Alessandro Island and the dam of Lake Perris should be avoided when placing in situ sensors. Furthermore, the location of sensor placement is dependent on seasonal fluctuations of PM10 which can be modeled using the techniques used in this study.

  11. Sessile nanofluid droplet drying.

    Science.gov (United States)

    Zhong, Xin; Crivoi, Alexandru; Duan, Fei

    2015-03-01

    Nanofluid droplet evaporation has gained much audience nowadays due to its wide applications in painting, coating, surface patterning, particle deposition, etc. This paper reviews the drying progress and deposition formation from the evaporative sessile droplets with the suspended insoluble solutes, especially nanoparticles. The main content covers the evaporation fundamental, the particle self-assembly, and deposition patterns in sessile nanofluid droplet. Both experimental and theoretical studies are presented. The effects of the type, concentration and size of nanoparticles on the spreading and evaporative dynamics are elucidated at first, serving the basis for the understanding of particle motion and deposition process which are introduced afterward. Stressing on particle assembly and production of desirable residue patterns, we express abundant experimental interventions, various types of deposits, and the effects on nanoparticle deposition. The review ends with the introduction of theoretical investigations, including the Navier-Stokes equations in terms of solutions, the Diffusion Limited Aggregation approach, the Kinetic Monte Carlo method, and the Dynamical Density Functional Theory. Nanoparticles have shown great influences in spreading, evaporation rate, evaporation regime, fluid flow and pattern formation of sessile droplets. Under different experimental conditions, various deposition patterns can be formed. The existing theoretical approaches are able to predict fluid dynamics, particle motion and deposition patterns in the particular cases. On the basis of further understanding of the effects of fluid dynamics and particle motion, the desirable patterns can be obtained with appropriate experimental regulations.

  12. Accumulation of heavy metals in dietary vegetables and cultivated soil horizon in organic farming system in relation to atmospheric deposition in a seasonally dry tropical region of India.

    Science.gov (United States)

    Pandey, J; Pandey, Usha

    2009-01-01

    Increasing consciousness about future sustainable agriculture and hazard free food production has lead organic farming to be a globally emerging alternative farm practice. We investigated the accumulation of air-borne heavy metals in edible parts of vegetables and in cultivated soil horizon in organic farming system in a low rain fall tropical region of India. The factorial design of whole experiment consisted of six vegetable crops (tomato, egg plant, spinach, amaranthus, carrot and radish) x two treatments (organic farming in open field and organic farming in glasshouse (OFG)) x seven independent harvest of each crop. The results indicated that except for Pb, atmospheric deposition of heavy metals increased consistently on time scale. Concentrations of heavy metals in cultivated soil horizon and in edible parts of open field grown vegetables increased over time and were significantly higher than those recorded in OFG plots. Increased contents of heavy metals in open field altered soil porosity, bulk density, water holding capacity, microbial biomass carbon, substrate-induced respiration, alkaline phosphatase and fluorescein diacetate hydrolytic activities. Vegetable concentrations of heavy metal appeared in the order Zn > Pb > Cu > Ni > Cd and were maximum in leaves (spinach and amaranths) followed by fruits (tomato and egg plant) and minimum in roots (carrot and radish). Multiple regression analysis indicated that the major contribution of most heavy metals to vegetable leaves was from atmosphere. For roots however, soil appeared to be equally important. The study suggests that if the present trend of atmospheric deposition is continued, it will lead to a destabilizing effect on this sustainable agricultural practice and will increase the dietary intake of toxic metals.

  13. Estimates of power deposited via cesium/barium beta and gamma radiation captured in components of a Hanford cesium chloride capsule and by components of overpacked capsules placed in an interim dry storage facility

    Energy Technology Data Exchange (ETDEWEB)

    Roetman, V.E., Westinghouse Hanford

    1996-12-23

    The deposition of power in Hanford cesium chloride capsules and in the components of design concepts for overpacking and interim storage were determined as requested (Randklev, 1996a). The power deposition results from the selective capture of gamma and beta radiation coming from the decay of the 137CS isotope in the CsCl contained in the capsules. The following three cases were analyzed: (a) a single CsCl capsule, (b) an overpack containing eight CsCl capsules, and (c) an infinite square array of such overpacks as placed in tubes of a interim dry storage facility. The power deposition was expressed as watts per gram for each of the respective physical design components in these three cases. Per the analyses request and guidance (Randklev 1996a), the primary analysis objective was to characterize, for each case, the power deposition across the radial cross-section at the expected axial position of maximum deposition. As requested, this primary part of the analysis work was done using choices for component dimension and material properties that would reasonably characterize the maximum deposition profile across the salt (CsCl) and the inner capsule barrier of the double walled metal capsule system used to construct the Hanford capsules. The secondary objective was to further evaluate the deposition behavior relative to the influence of axial position. The guidance (Randklev 1996a) also requested 1797 an analysis case that involved a lag-storage pit in a hot-cell, in which a cylindrical metal basket from a transportation cask would be used to position several capsules in the lag-storage pit. Although the basic model for the lag storage concept evaluation was essentially completed by the end of FY-96, the analysis was not run because of the need to prioritize and limit the work scope due to funding limitations for FY-97. The specific purpose for performing the subject set of analyses (Randklev 1996a) is to obtain power deposition values (i.e., per the decay of T37cs

  14. An ozone budget for the UK: using measurements from the national ozone monitoring network; measured and modelled meteorological data, and a 'big-leaf' resistance analogy model of dry deposition

    Energy Technology Data Exchange (ETDEWEB)

    Coyle, M.; Smith, R.; Fowler, D

    2003-05-01

    A method of calculating a mass budget for O{sub 3} in the UK boundary layer is presented which shows that the spatial scale of the UK is small relative to the footprint of the atmosphere influenced by UK emissions. - Data from the UK national air-quality monitoring network are used to calculate an annual mass budget for ozone (O{sub 3}) production and loss in the UK boundary layer during 1996. Monthly losses by dry deposition are quantified from 1 kmx1 km scale maps of O{sub 3} concentration and O{sub 3} deposition velocities based on a 'big-leaf' resistance analogy. The quantity of O{sub 3} deposition varies from {approx}50 Gg-O{sub 3} month{sup -1} in the winter to over 200 Gg-O{sub 3} month{sup -1} in the summer when vegetation is actively absorbing O{sub 3}. The net O{sub 3} production or loss in the UK boundary layer is found by selecting days when the UK is receiving 'clean' Atlantic air from the SW to NW. In these conditions, the difference in O{sub 3} concentration observed at Mace Head and a rural site on the east coast of the UK indicates the net O{sub 3} production or loss within the UK boundary layer. A simple box model is then used to convert the concentration difference into a mass. The final budget shows that for most of the year the UK is a net sink for O{sub 3} (-25 to -800 Gg-O{sub 3} month{sup -1}) with production only exceeding losses in the photochemically active summer months (+45 Gg-O{sub 3} month{sup -1})

  15. Dry and wet atmospheric deposition of organic carbon in coastal and water areas of the northeastern part of the Sea of Azov

    Science.gov (United States)

    Sorokina, V. V.; Soier, V. G.

    2016-09-01

    The paper reports on new data focusing on organic carbon contained in aeolian material and precipitation falling on coastal and water areas of the northeastern part of the Sea of Azov. Atmospheric deposition was sampled in 2006-2014. The particulate organic carbon content varied from 4 to 27% in aeolian dust samples. The concentration of the organic carbon dissolved in rainwater was from 1.6 to 4.3 mg C/L, and from 0.9 to 16.6 mg C/L in snow. The particulate organic carbon content varied from 2 to 43% in snow. Intensity of aeolian dust settling decreased from 178 to 33 mg/m2 per day with distance from a source of dust; in contrast, the relative content of organic matter increased. In a spring-summer season the aeolian organic carbon fluxes varied from 12 to 18 mg C/m2 per day in Rostov-on-Don, from 28 to 48 mg C/m2 per day on the Gulf of Taganrog coast, and from 20 to 80 mg C/m2 per day in the water area of the Gulf of Taganrog.

  16. The influence of carrier roughness on adhesion, content uniformity and the in vitro deposition of terbutaline sulphate from dry powder inhalers.

    Science.gov (United States)

    Flament, Marie-Pierre; Leterme, Pierre; Gayot, Anne

    2004-05-01

    The aim of this study was to establish a correlation between carrier characteristics and the dispersibility of drug from the blend. The influence of the roughness of a commonly used carrier material, lactose monohydrate, on the adhesion, dose uniformity, and aerodynamic properties of a model drug, terbutaline sulphate was investigated. Evaluation of adhesion was carried out with a mechanical sieve and an Alpine air-jet sieve. For the characterisation of lactose roughness, we used image analysis software. Aerodynamic evaluation of fine particle dose and emitted dose was obtained using a twin stage impinger. The study with the mechanical sieve demonstrated that at least 60% of drug adheres to lactose. The Alpine air-jet sieve assays showed there was a correlation between drug separation from a carrier by sieving and that obtained from longer in vitro deposition studies. Adhesion, blend homogeneity and stability are related to the surface roughness of the lactose used as carrier. There is a linear relationship between the parameters "fine particle fraction" and "roughness". A compromise between homogeneity and drug liberation must be found: a certain roughness is necessary to allow for drug adhesion and blend homogeneity, but if too high it will prevent drug liberation after inhalation.

  17. Dry Etching

    DEFF Research Database (Denmark)

    Stamate, Eugen; Yeom, Geun Young

    2016-01-01

    Production of large-area flat panel displays (FPDs) involves several pattern transfer and device fabrication steps that can be performed with dry etching technologies. Even though the dry etching using capacitively coupled plasma is generally used to maintain high etch uniformity, due to the need...... for the higher processing rates in FPDs, high-density plasma processing tools that can handle larger-area substrate uniformly are more intensively studied especially for the dry etching of polysilicon thin films. In the case of FPD processing, the current substrate size ranges from 730 × 920 mm (fourth...... generation) to 2,200 × 2,500 mm (eighth generation), and the substrate size is expected to increase further within a few years. This chapter aims to present relevant details on dry etching including the phenomenology, materials to be etched with the different recipes, plasma sources fulfilling the dry...

  18. Analysis on Input of Atmospheric Nitrogen Dry Deposition in Urumqi%乌鲁木齐市区大气氮素干沉降的输入性分析

    Institute of Scientific and Technical Information of China (English)

    张伟; 刘学军; 胡玉昆; 李凯辉; 沈健林; 骆晓声; 宋韦

    2011-01-01

    Atmospheric concentrations of NH3,NO2,particulate NH+4(PNH+4) and NO-3(PNO-3) were measured from the samples collected with passive samplers and particulate samplers in Urumqi and its suburbs during the period from August 2009 to March 2010 to estimate atmospheric dry deposition of nitrogen(N) in this region.The results show that NH3 concentration at the Institute of Soil and Fertilizer Research(ISFR,suburban site) was higher than that at the Xinjiang Institute of Ecology and Geography(XIEG,urban site),while the concentrations of other atmospheric reactive N compositions(NO2,particulate NH+4 and NO-3) were higher at XIEG than those at ISFR.The mean concentrations of NH3-N,NO2-N,PNH+4-N,PNO-3-N and PM10(particulate matters with aerodynamic diameter less than 10 μm) at XIEG were 4.49,4.31,2.52,11.84 and 225 μg/m3,and those at ISFR were 4.63,2.32,2.34,7.59 and 188 μg/m3,respectively.Based on the measured concentrations and the dry deposition velocities cited from the references,it was estimated that the atmospheric dry deposition of N was 28.7 kg/(hm2·a) during the sampling period at XIEG and 21.6 kg/(hm2·a) at ISFR,in which the proportion of NHx(NH3+ PNH+4) accounted for 65.7% at XIEG and 69.4% at ISFR,NH3 was dominant during the period from August to November,and PNH+4 was dominant during the period from December to next March.%2009年8月至2010年3月在乌鲁木齐市及城郊,通过大气颗粒物采样器、气体被动采样器对大气氮素干沉降进行连续性监测。结果表明:除NH3浓度值ISFR(土肥所)高于XIEG(生地所)外,其他活性氮成分的浓度XIEG均大于ISFR。NO2-N,NH3-N(气态),PNO 3--N,PNH 4+-N(气溶胶态)和PM10(空气动力学当量直径在10μm以下的颗粒物)在监测点XIEG的平均浓度为4.31,4.49,2.52,11.84,224.66μg/m3,在ISFR的监测值为2.32,4.63,2.34,7.

  19. century drying

    Science.gov (United States)

    Cook, Benjamin I.; Smerdon, Jason E.; Seager, Richard; Coats, Sloan

    2014-11-01

    Global warming is expected to increase the frequency and intensity of droughts in the twenty-first century, but the relative contributions from changes in moisture supply (precipitation) versus evaporative demand (potential evapotranspiration; PET) have not been comprehensively assessed. Using output from a suite of general circulation model (GCM) simulations from phase 5 of the Coupled Model Intercomparison Project, projected twenty-first century drying and wetting trends are investigated using two offline indices of surface moisture balance: the Palmer Drought Severity Index (PDSI) and the Standardized Precipitation Evapotranspiration Index (SPEI). PDSI and SPEI projections using precipitation and Penman-Monteith based PET changes from the GCMs generally agree, showing robust cross-model drying in western North America, Central America, the Mediterranean, southern Africa, and the Amazon and robust wetting occurring in the Northern Hemisphere high latitudes and east Africa (PDSI only). The SPEI is more sensitive to PET changes than the PDSI, especially in arid regions such as the Sahara and Middle East. Regional drying and wetting patterns largely mirror the spatially heterogeneous response of precipitation in the models, although drying in the PDSI and SPEI calculations extends beyond the regions of reduced precipitation. This expansion of drying areas is attributed to globally widespread increases in PET, caused by increases in surface net radiation and the vapor pressure deficit. Increased PET not only intensifies drying in areas where precipitation is already reduced, it also drives areas into drought that would otherwise experience little drying or even wetting from precipitation trends alone. This PET amplification effect is largest in the Northern Hemisphere mid-latitudes, and is especially pronounced in western North America, Europe, and southeast China. Compared to PDSI projections using precipitation changes only, the projections incorporating both

  20. 沙尘传输路径上气溶胶浓度与干沉降通量的粒径分布特征%Size-Dependent Mass and Dry Deposition Fluxes of Atmospheric Aerosols along Dust Transport Routes

    Institute of Scientific and Technical Information of China (English)

    闫涵; 高会旺; 姚小红; 石金辉; 于超

    2012-01-01

    Using the size-segregated measurements of atmospheric aerosols collected in Beijing and Qingdao in China and Fukuoka in Japan during the spring of 2002, the size distributions of the mass of atmospheric aerosols with aerodynamic diameter (Dp) ≤ 11 μm (PM11) along dust transport routes are investigated. The size distribution of these aerosols in mass concentration during non-dust periods exhibits a bimodal pattern, i. e. , a fine modes with Dp< 2.1 μm and a coarse mode between 2.1 μm and 11 μm. On the other hand, the size distribution of these aerosols in mass concentration during dust periods attempts to exhibit a uni-modal pattern in the coarse particle size range. The coarse mode diameter decreases with the distance from the dust source zone to the west and east coast oi the Yellow Sea during the heavy dust periods. It is not case in regular dust periods. The size-dependent dry deposition fluxes oi the aerosols over the Yellow Sea in springtime are estimated using an improved Williams' modeL The dry deposition fluxes increase with the increasing size in the coarse particle size range during the non-dust and dust periods. It appears that no evident variations occurred in the fine mode. The estimated PM11 fluxes over the Yellow Sea during the dust and non-dust periods range from 31.70 to 58.59 mg m-2d-1 and ranged from 8. 33 to 15.94 mg · m-2 · d-1, respectively. Although the dry deposition fluxes of the coarse particles increase evidently during dust periods, the relative contributions of the coarse particles to that of PM11 do not change significantly regardless of the occurrence of and absence of dust events. The authors find that coarse particles are the main contributor to the PM11 dry deposition in springtime over the Yellow Sea, the percentage reaches over 94. 2%.%利用2002年春季中国北京、青岛和日本福冈3个地区的分级气溶胶浓度资料,结合改进的Williams模型,分析了沙尘传输路径上空气动力学直径≤11

  1. Dry cell battery poisoning

    Science.gov (United States)

    Batteries - dry cell ... Acidic dry cell batteries contain: Manganese dioxide Ammonium chloride Alkaline dry cell batteries contain: Sodium hydroxide Potassium hydroxide Lithium dioxide dry cell batteries ...

  2. Dry release of suspended nanostructures

    DEFF Research Database (Denmark)

    Forsén, Esko Sebastian; Davis, Zachary James; Dong, M.;

    2004-01-01

    A dry release method for fabrication of suspended nanostructures is presented. The technique has been combined with an anti-stiction treatment for fabrication of nanocantilever based nanoelectromechanical systems (NEMS). The process combines a dry release method, using a supporting layer of photo......A dry release method for fabrication of suspended nanostructures is presented. The technique has been combined with an anti-stiction treatment for fabrication of nanocantilever based nanoelectromechanical systems (NEMS). The process combines a dry release method, using a supporting layer......, the technique enables long time storage and transportation of produced devices without the risk of stiction. By combining the dry release method with a plasma deposited anti-stiction coating both fabrication induced stiction, which is mainly caused by capillary forces originating from the dehydration...

  3. Dry Mouth

    Science.gov (United States)

    ... Use a fluoride rinse or brush-on fluoride gel before bedtime. See your dentist at least twice yearly to have your teeth examined and plaque removed, to help prevent tooth decay. Several herbal remedies have been used historically to treat dry ...

  4. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Causes of Dry Eye Dry Eye Treatment What Is Dry Eye? Written By: Kierstan Boyd Reviewed By: ... your eyes do not produce enough tears, it is called dry eye. Dry eye is also when ...

  5. Characteristics and Source Apportionment of Water-soluble Ions in Dry Deposition in the Summer and Autumn of Nanjing%南京夏秋季节大气干沉降水溶性离子特征及来源分析

    Institute of Scientific and Technical Information of China (English)

    秦阳; 朱彬; 邹嘉南; 庞博

    2016-01-01

    A total of 84 effective dry deposition samples were collected from July to October, 2014 in Nanjing, and the chemical composition and source apportionment of water-soluble ions dry deposition in the summer and autumn season were discussed. The results indicated that the average pH was 6. 2, and the dry deposition samples usually appeared neutral. Ca2 + and NH +4 were the major cations and their average daily concentrations were 115. 7 μeq•L - 1 and 31. 2 μeq•L - 1 ,accounting for 68. 3% and 18. 6% of total cations, respectively. SO2 -4 , Cl - and NO2 -3 were the main anions, and their average daily concentrations were 30. 4, 20. 7 and 18. 7μeq•L - 1 , a total of 89. 2% of the total anions, respectively. High temperature and humidity of meteorological factors and contaminated air mass affected dry deposition. Local air mass had greater impact on dry deposition pollution, which indicated that dry deposition pollution had local property. In summer and autumn seasons in Nanjing, the stationary sources had more contributions to atmospheric dry deposition of water-soluble ions than mobile sources, while the environmental control measures for the Nanjing Youth Olympic Games had greater effect on stationary sources than mobile sources. Studies of the origins of major ions indicated that SO2 -4 and NO2 -3 were mostly attributed by the anthropogenic activities, and Cl - was mainly from ocean sources, while K + and Mg2 + were mostly from the terrestrial input.%本研究利用采集的2014年7~10月南京地区84个有效干沉降样品,探讨了南京夏秋季节大气干沉降中水溶性离子的化学组成及其来源.结果表明南京夏秋季干沉降样品平均 pH 为6.2,干沉降偏中性. Ca2+和 NH +4是主要的阳离子,日均浓度分别为115.7μeq•L -1和31.2μeq•L -1,分别占阳离子总量的68.3%和18.6%.阴离子以 SO2-4、 Cl -和 NO2-3为主,日均浓度为30.4、20.7和18.7μeq•L -1,共占总阴离子的89.2%.干沉降浓度变

  6. A Micrometeorological Perspective on Deposition

    DEFF Research Database (Denmark)

    Jensen, Niels Otto

    1981-01-01

    An expression for the dry deposition velocity is given in terms of constant flux layer scaling. Numerical values of upper bounds on the deposition velocity is given for a typical situation. Some remarks are then offered on the relative merits of various ways in which the combined diffusion...

  7. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Eye Symptoms Causes of Dry Eye Dry Eye Treatment What Is Dry Eye? Written By: Kierstan Boyd ... your vision. Privacy Policy Related New Dry Eye Treatment is a Tear-Jerker Jul 21, 2017 Three ...

  8. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Español Eye Health / Eye Health A-Z Dry Eye Sections What Is Dry Eye? Dry Eye Symptoms ... Dry Eye Dry Eye Treatment What Is Dry Eye? Written By: Kierstan Boyd Reviewed By: Brenda Pagan- ...

  9. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Español Eye Health / Eye Health A-Z Dry Eye Sections What Is Dry Eye? Dry Eye Symptoms ... Dry Eye Dry Eye Treatment What Is Dry Eye? Leer en Español: ¿Qué Es el Ojo Seco? ...

  10. [Monitoring nitrogen deposition on temperate grassland in Inner Mongolia].

    Science.gov (United States)

    Zhang, Ju; Kang, Rong-hua; Zhao, Bin; Huang, Yong-mei; Ye, Zhi-xiang; Duan, Lei

    2013-09-01

    Nitrogen deposition on temperate steppe was monitored from November 2011 to October 2012 in Taipusi County, Inner Mongolia. The dry deposition of gaseous nitrogen compounds was calculated based on online-monitored atmospheric concentrations of NH3 and NO2 and dry deposition velocity simulated by CMAQ model. The wet deposition, dry deposition of particle, and throughfall deposition were also estimated by collecting rainfall, dust fall, and throughfall samples and the chemical analysis of NH4+ and NO3-concentrations. Results showed that the total deposition of nitrogen was up to 3.43 g x (m2 x a)(-1), which might be harmful to the ecosystem. The wet deposition accounted for about 44% of the total deposition, while dry deposition of gases and particle accounted for 38% and 18%, respectively. Since the deposition contributed more than wet deposition, a great attention should be paid on dry deposition monitoring. However, the very simple method for total deposition monitoring based on throughfall seemed not suitable for grassland because the monitored throughfall deposition was much lower than the total deposition. In addition, reduced nitrogen (NH4+ and NH3) contributed to 71% of the total deposition, while oxidation nitrogen (NO3- and NO2) was only 29%. Therefore, NH3 emission reduction should be considered as important as nitrogen oxides (NO3x) for controlling nitrogen deposition.

  11. Short-term post-wildfire dry-ravel processes in a chaparral fluvial system

    Science.gov (United States)

    Florsheim, Joan L.; Chin, Anne; O'Hirok, Linda S.; Storesund, Rune

    2016-01-01

    Dry ravel, the transport of sediment by gravity, transfers material from steep hillslopes to valley bottoms during dry conditions. Following wildfire, dry ravel greatly increases in the absence of vegetation on hillslopes, thereby contributing to sediment supply at the landscape scale. Dry ravel has been documented as a dominant hillslope erosion mechanism following wildfire in chaparral environments in southern California. However, alteration after initial deposition is not well understood, making prediction of post-fire flood hazards challenging. The majority of Big Sycamore Canyon burned during the May 2013 Springs Fire leaving ash and a charred layer that covered hillslopes and ephemeral channels. Dry-ravel processes following the fire produced numerous deposits in the hillslope-channel transition zone. Field data focus on: 1) deposition from an initial post-wildfire dry-ravel pulse; and 2) subsequent alteration of dry ravel deposits over a seven-month period between September 2013 and April 2014. We quantify geomorphic responses in dry ravel deposits including responses during the one small winter storm that generated runoff following the fire. Field measurements document volumetric changes after initial post-wildfire deposition of sediment derived from dry ravel. Erosion and deposition mechanisms that occurred within dry-ravel deposits situated in the hillslope-channel transition zone included: 1) mobilization and transport of a portion or the entire deposit by fluvial erosion; 2) rilling on the surface of the unconsolidated deposits; 3) deposition on deposits via continued hillslope sediment supply; and 4) mass wasting that transfers sediment within deposits where surface profiles are near the angle of repose. Terrestrial LiDAR scanning point clouds were analyzed to generate profiles quantifying depth of sediment erosion or deposition over remaining dry ravel deposits after the first storm season. This study contributes to the understanding of potential

  12. Hirabayashi, Satoshi; Kroll, Charles N.; Nowak, David J. 2011. Component-based development and sensitivity analyses of an air pollutant dry deposition model. Environmental Modelling & Software. 26(6): 804-816.

    Science.gov (United States)

    Satoshi Hirabayashi; Chuck Kroll; David Nowak

    2011-01-01

    The Urban Forest Effects-Deposition model (UFORE-D) was developed with a component-based modeling approach. Functions of the model were separated into components that are responsible for user interface, data input/output, and core model functions. Taking advantage of the component-based approach, three UFORE-D applications were developed: a base application to estimate...

  13. METALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    <正>20070291 Gong Ping (Northern Fujian Geological Party, Shaozou 354000) Discussion on Geological Characteristics and Control Factors of the Shimen Au-polymetallic Deposit in Zhenghe County, Fujian Province (Geology of Fujian, ISSN1001-3970, CN38-1080/P, 25(1), 2006, p.18-24, 2 illus., 2 tables, 1 ref.) Key words: gold deposits, polymetallic deposits, Fujian Province

  14. Contribution of Atmospheric Nitrogen Compounds to N Deposition in a Broadleaf Forest of Southern China

    Institute of Scientific and Technical Information of China (English)

    HU Zheng-Yi; XU Cheng-Kai; ZHOU Li-Na; SUN Ben-Hua; HE Yuan-Qiu; ZHOU Jing; CAO Zhi-Hong

    2007-01-01

    A one-year study in a typical red soil region of southern China was conducted to determine atmospheric nitrogen (N) fluxes of typical N compounds (NH3, NH4-N, NO3-N, and NO2) and contribution of three sources (gas, rainwater, and particles) to N deposition. From July 2003 to June 2004, the total atmospheric N deposition was 70.7 kg N ha-1, with dry deposition accounting for 75% of the total deposition. Dry NH3 deposition accounted for 73% of the dry deposition and 55% of the total deposition. Moreover, NO2 contributed 11% of the dry deposition and 8% of the total deposition. Reduced N compounds (NH+4 and NH3) were the predominate contributors, accounting for 66% of the total deposition. Therefore, atmospheric N deposition should be considered when soil acidification and critical loads of atmospheric deposition on soils are estimated.

  15. 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...

  16. 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...

  17. 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...

  18. ROE Total Sulfur Deposition 2011-2013

    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 2011 to 2013 at a set of point locations across the...

  19. Solubility of deposited airborne heavy metals

    Science.gov (United States)

    Cizmecioglu, Sibel C.; Muezzinoglu, Aysen

    2008-09-01

    Toxic effects of heavy metals in water and soil environments are important. Quantifying the heavy metal concentrations and their solubilities in dry and wet deposition samples is part of atmospheric research. Soluble fractions of the deposited air pollutants are important in food chain mechanisms as heavy metals may cause ecotoxic impacts. In this study, the solubilities of Cr, Cd, Pb, Cu, Zn, and Ni were investigated in deposition samples for total, dissolved, and suspended fractions after collection in a surrogate, water-surface sampler in Izmir, Turkey, during October 2003 to June 2004. To find overall solubility of each metal in dry and wet deposition samples, concentrations in soluble and suspended phases of aqueous solutions were analyzed separately. Ratios between total and dissolved forms and the metals in the same forms were analyzed and evaluated statistically. It was found that the deposited metal fluxes were significantly correlated in wet deposition with the highest correlation between Cd and Pb in the soluble and total forms. Comparatively smaller correlations were found between these metal fluxes in dry deposition samples. Results of this study showed the importance of metal pollution, especially ecotoxic properties of heavy metals in wet deposition far more than dry deposition.

  20. Effect of Soil texture on Photosynthetic traits and the deposition of Dry matter accumulation of peanut%土壤质地对花生光合特性及干物质积累分配的影响

    Institute of Scientific and Technical Information of China (English)

    贾立华; 王月福; 陈安余; 冯锴

    2013-01-01

    The paper explored the effect of soil texture on photosynthetic traits and detribution of dry matter accumulation of peanut,in order to explicit the suitable soil texture appropriated for high-yielding peanut cultivation.The soil texture including Sandy soil,Clay and Loam,and the experiment were implemented in box plant method.The results showed that the early period of peanut growth and development is Sandy soil>Loam>Clay and the later period is Loam>Sandy soil>Clay on Leaf area per plant,Functional leaf chlorophyll content,Net photosynthetic rate and Distribution of dry matter accumulation of peanut.Sandy soil is in favor of early period of photosynthetic matter accumulation,Loam is in favor of whole period,and Clay is not conductive to the whole period.Loam is more suitable than Clay and Sandy soil on distribution ratio of peanut organ dry matter accumulation.Loam has a higher pod yield than Sandy soil and Clay.%为了明确适合花生生长获得高产的土壤类型,采用箱栽的方法,研究了不同质地土壤(砂土、壤土、粘土)对花生光合特性及干物质积累分配的影响.结果表明,花生单株叶面积、功能叶叶绿素SPAD值、净光合速率和植株总干物质重在生育前期表现为砂土>壤土>粘土,在生育后期则表现为壤土>砂土>粘土.砂土有利于花生前期光合物质积累,壤土则在整个生育期内均有利于花生光合物质积累,而粘土则在整个生育期内均不利于花生光合物质积累.壤土花生各器官干物质分配比例较粘土和砂土合理.壤土的荚果产量显著高于砂土和粘土.

  1. Energy Efficient Textile Drying

    OpenAIRE

    Brunzell, Lena

    2006-01-01

    Traditionally, textiles were dried outdoors with the wind and the sun enhancing the drying process. Tumble dryers offer a fast and convenient way of drying textiles independent of weather conditions. Tumble dryers, however, consume large amounts of electrical energy. Over 4 million tumble dryers are sold each year in Europe and a considerable amount of energy is used for drying of clothes. Increasing energy costs and the awareness about environmental problems related to a large energy use has...

  2. Review of Gaussian diffusion-deposition models

    Energy Technology Data Exchange (ETDEWEB)

    Horst, T.W.

    1979-01-01

    The assumptions and predictions of several Gaussian diffusion-deposition models are compared. A simple correction to the Chamberlain source depletion model is shown to predict ground-level airborne concentrations and dry deposition fluxes in close agreement with the exact solution of Horst.

  3. Review:Resuspension of wall deposits in spray dryers

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Wall deposition occurs in spray dryers when dried or partially dried particles contact and adhere to the walls during operation, thus reducing the yield of product collected. Wall deposits also present a product contamination risk and a fire or explosion risk when spray drying products that oxidize exothermically, such as milk powder. Re-entrainment is the resuspension of spray dryer wall deposits into the main gas stream for collection as product. Literature suggests that the process for re-entrainment of particles from spray dryer wall deposits is strongly dependent on particle size and gas velocity.

  4. Dry vacuum pumps

    Science.gov (United States)

    Sibuet, R.

    2008-05-01

    For decades and for ultimate pressure below 1 mbar, oil-sealed Rotary Vane Pumps have been the most popular solution for a wide range of vacuum applications. In the late 80ies, Semiconductor Industry has initiated the development of the first dry roughing pumps. Today SC applications are only using dry pumps and dry pumping packages. Since that time, pumps manufacturers have developed dry vacuum pumps technologies in order to make them attractive for other applications. The trend to replace lubricated pumps by dry pumps is now spreading over many other market segments. For the Semiconductor Industry, it has been quite easy to understand the benefits of dry pumps, in terms of Cost of Ownership, process contamination and up-time. In this paper, Technology of Dry pumps, its application in R&D/industries, merits over conventional pumps and future growth scope will be discussed.

  5. Deposição e acúmulo de matéria seca e nutrientes em serapilheira em um bosque de sabiá (Mimosa caesalpiniifolia Benth. Litter dry mass and nutrient deposition and accumulation in a sabiá (Mimosa caesalpiniifolia Benth. woodlot

    Directory of Open Access Journals (Sweden)

    Rinaldo Luiz Caraciolo Ferreira

    2007-02-01

    collected monthly from October 2000 to September 2001, and separated into leaves, twigs, flowers, pods and mixed portions. Undecomposed organic mantle was randomly sampled nearby collector boxes, to a total of 20 monthly samples, from which a 0.30 x 0.30 m composed sample was collected. The collected material was also hand separated into leaves, twigs, flowers, pods and mixed portions. All collected material was dried at 60°C until constant weight was achieved. Highest monthly litter deposition and leaf and pod fractions occurred in October, probably due to initiation of dry period. Litter deposition and stock were estimated at 7830.44 kg.ha-1.year-1 and 8906.9 kg.ha-1, respectively, with the leaf fraction dominating. Leaf fraction was the richest in nutrient content.

  6. NONMETALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    <正>20102406 Chen Gang(China University of Geosciences,Beijing 100083,China);Li Fengming Discussion on Geological Characteristics and Genesis of Yuquanshan Graphite Deposit of Xinjiang(Xinjiang Geology,ISSN1000-8845,CN65-1092/P,27(4),2009,p.325-329,4 illus.,4 tables,5 refs.)Key words:graphite deposit,XinjiangYuquanshan graphite deposit of Xinjiang occurs in mica-quartz schist of Xingeer Information which belongs to Xinditate Group of Lower Pt in Kuluketage Block of Tarim paleo-continent,and experiences two mineralizing periods of

  7. Drying and energy technologies

    CERN Document Server

    Lima, A

    2016-01-01

    This book provides a comprehensive overview of essential topics related to conventional and advanced drying and energy technologies, especially motivated by increased industry and academic interest. The main topics discussed are: theory and applications of drying, emerging topics in drying technology, innovations and trends in drying, thermo-hydro-chemical-mechanical behaviors of porous materials in drying, and drying equipment and energy. Since the topics covered are inter- and multi-disciplinary, the book offers an excellent source of information for engineers, energy specialists, scientists, researchers, graduate students, and leaders of industrial companies. This book is divided into several chapters focusing on the engineering, science and technology applied in essential industrial processes used for raw materials and products.

  8. NONMETALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    <正>20140876 Gao Junbo(College of Resources and Environmental Engineering,Guizhou University,Guiyang 550025,China);Yang Ruidong Study on the Strontium Isotopic Composition of Large Devonian Barite Deposits from Zhenning,Guizhou Province(Geochimica,

  9. Ambient Dried Aerogels

    Science.gov (United States)

    Jones, Steven M.; Paik, Jong-Ah

    2013-01-01

    A method has been developed for creating aerogel using normal pressure and ambient temperatures. All spacecraft, satellites, and landers require the use of thermal insulation due to the extreme environments encountered in space and on extraterrestrial bodies. Ambient dried aerogels introduce the possibility of using aerogel as thermal insulation in a wide variety of instances where supercritically dried aerogels cannot be used. More specifically, thermoelectric devices can use ambient dried aerogel, where the advantages are in situ production using the cast-in ability of an aerogel. Previously, aerogels required supercritical conditions (high temperature and high pressure) to be dried. Ambient dried aerogels can be dried at room temperature and pressure. This allows many materials, such as plastics and certain metal alloys that cannot survive supercritical conditions, to be directly immersed in liquid aerogel precursor and then encapsulated in the final, dried aerogel. Additionally, the metalized Mylar films that could not survive the previous methods of making aerogels can survive the ambient drying technique, thus making multilayer insulation (MLI) materials possible. This results in lighter insulation material as well. Because this innovation does not require high-temperature or high-pressure drying, ambient dried aerogels are much less expensive to produce. The equipment needed to conduct supercritical drying costs many tens of thousands of dollars, and has associated running expenses for power, pressurized gasses, and maintenance. The ambient drying process also expands the size of the pieces of aerogel that can be made because a high-temperature, high-pressure system typically has internal dimensions of up to 30 cm in diameter and 60 cm in height. In the case of this innovation, the only limitation on the size of the aerogels produced would be in the ability of the solvent in the wet gel to escape from the gel network.

  10. Ocean Dynamics: Vietnam DRI

    Science.gov (United States)

    2014-09-30

    Dynamics: Vietnam DRI Robert Pinkel Marine Physical Laboratory Scripps Institution of Oceanography La Jolla California 92093-0213 Phone: (858) 534...DATES COVERED 00-00-2014 to 00-00-2014 4. TITLE AND SUBTITLE Ocean Dynamics: Vietnam DRI 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM...cycle.. The Thorpe-scale estimates are local to Site III. South China Sea Process Cruise 2014 Under Vietnam DRI funding, Researcher Drew Lucas

  11. NONMETALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>20122457 Cai Jianshe ( Fujian Institute of Geological Survey and Drawing,Fuzhou 350011,China ) On the Geologic Characteristics and Genesis of the Longtangsi Fluorite Deposit in Pucheng County,Fujian Province ( Geology of Fujian,ISSN1001-3970,CN35-1080 / P,30 ( 4 ), 2011,p.301-306,3illus.,1table,6 refs.,with English abstract ) Key words:fluorspar deposit,Fujian Province

  12. Dry etching for microelectronics

    CERN Document Server

    Powell, RA

    1984-01-01

    This volume collects together for the first time a series of in-depth, critical reviews of important topics in dry etching, such as dry processing of III-V compound semiconductors, dry etching of refractory metal silicides and dry etching aluminium and aluminium alloys. This topical format provides the reader with more specialised information and references than found in a general review article. In addition, it presents a broad perspective which would otherwise have to be gained by reading a large number of individual research papers. An additional important and unique feature of this book

  13. Atmospheric nitrogen budget in Sahelian dry savannas

    Directory of Open Access Journals (Sweden)

    C. Delon

    2010-03-01

    Full Text Available The atmospheric nitrogen budget depends on emission and deposition fluxes both as reduced and oxidized nitrogen compounds. In this study, a first attempt at estimating the Sahel nitrogen budget for the year 2006 is made, through measurements and simulations at three stations from the IDAF network situated in dry savanna ecosystems. Dry deposition fluxes are estimated from measurements of NO2, HNO3 and NH3 gaseous concentrations and from simulated dry deposition velocities, and wet deposition fluxes are calculated from NH4+ and NO3 concentrations in samples of rain. Emission fluxes are estimated including biogenic emission of NO from soils (an Artificial Neural Network module has been inserted into the ISBA-SURFEX surface model, emission of NOx and NH3 from domestic fires and biomass burning, and volatilization of NH3 from animal excreta. Uncertainties are calculated for each contribution of the budget.

    This study uses original and unique data from remote and hardly-ever-explored regions.The monthly evolution of oxidized N compounds shows that emission and deposition increase at the beginning of the rainy season because of large emissions of biogenic NO (pulse events. Emission of oxidized compounds is dominated by biogenic emission from soils (domestic fires and biomass burning of oxidized compounds account for 0 to 13% at the most at the annual scale, depending on the station, whereas emission of NH3 is dominated by the process of volatilization from soils. At the annual scale, the average gaseous dry deposition accounts for 47% of the total estimated deposition flux, for both oxidized and reduced compounds. The average estimated wet plus dry deposition flux in dry savanna ecosystems is 7.5±1.8 kgN ha−1 yr−1, with approximately 30% attributed to oxidized compounds, and the rest attributed

  14. Dry-Mass Sensing for Microfluidics

    CERN Document Server

    Müller, T; Knowles, T P J

    2014-01-01

    We present an approach for interfacing an electromechanical sensor with a microfluidic device for the accurate quantification of the dry mass of analytes within microchannels. We show that depositing solutes onto the active surface of a quartz crystal microbalance by means of an on-chip microfluidic spray nozzle and subsequent solvent removal provides the basis for the real-time determination of dry solute mass. Moreover, this detection scheme does not suffer from the decrease in the sensor quality factor and the viscous drag present if the measurement is performed in a liquid environment, yet allows solutions to be analysed. We demonstrate the sensitivity and reliability of our approach by controlled deposition of nanogram levels of salt and protein from a micrometer-sized channel.

  15. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Tips & Prevention News Ask an Ophthalmologist Patient Stories Español Eye Health / Eye Health A-Z Dry Eye ... Eye Treatment What Is Dry Eye? Leer en Español: ¿Qué Es el Ojo Seco? Written By: Kierstan ...

  16. NONMETALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>20110947 Chen Xinglong(Guizhou Bureau of Nonferrous Metal and Nuclear Geology,Guiyang 550005,China);Gong Heqiang Endowment Factors and Development & Utilization Strategy of Bauxite Resource in North Guizhou Province(Guizhou Geology,ISSN1000-5943,CN52-1059/P,27(2),2010,p.106-110,6 refs.,with English abstract)Key words:bauxite deposit,Guizhou Province20110948 Dang Yanxia(Mineral Resource & Reservoir Evaluation Center,Urumiq 830000,China);Fan Wenjun Geological Features and a Primary Study of Metallogenesis of the Wucaiwang Zeolite Deposit,Fuyun County(Xinjiang Geology,ISSN1000-8845,CN65-1092/P,28(2),2010,p.167-170,2 illus.,1 table,5 refs.)Key words:zeolite deposit,Xinjiang Nearly all zeolite deposits in the world result from low-temperature-alteration of glass-bearing volcanic rocks.The southern slope of the Kalamali Mountain is one of the regions where medium to acid volcanics are major lithological type,thus it is a preferred area to look for zeolite deposit.The Wucaiwang zeolite ore district consists of mainly acid volcanic-clastic rocks.

  17. Dry imaging cameras

    Directory of Open Access Journals (Sweden)

    I K Indrajit

    2011-01-01

    Full Text Available Dry imaging cameras are important hard copy devices in radiology. Using dry imaging camera, multiformat images of digital modalities in radiology are created from a sealed unit of unexposed films. The functioning of a modern dry camera, involves a blend of concurrent processes, in areas of diverse sciences like computers, mechanics, thermal, optics, electricity and radiography. Broadly, hard copy devices are classified as laser and non laser based technology. When compared with the working knowledge and technical awareness of different modalities in radiology, the understanding of a dry imaging camera is often superficial and neglected. To fill this void, this article outlines the key features of a modern dry camera and its important issues that impact radiology workflow.

  18. Atmospheric Sulfur Deposition for a Red Soil Broadleaf Forest in Southern China

    Institute of Scientific and Technical Information of China (English)

    XU Cheng-Kai; HU Zheng-Yi; CAI Zu-Cong; WANG Ti-Jian; HE Yuan-Qiu; CAO Zhi-Hong

    2004-01-01

    A two-year study in a typical red soil region of Southern China was conducted to determine 1) the dry deposition velocity (Vd) for SO2 and particulate SO2 4- above a broadleaf forest, and 2) atmospheric sulfur fluxes so as to estimate the contribution of various fractions in the total. Using a resistance model based on continuous hourly meteorological data, atmospheric dry sulfur deposition in a forest was estimated according to Vd and concentrations of both atmospheric SO2 and particulate SO24-. Meanwhile, wet S deposition was estimated based on rainfall and sulfate concentrations in the rainwater. Results showed that about 99% of the dry sulfur deposition flux in the forest resulted from SO2 dry deposition.In addition, the observed dry S deposition was greater in 2002 than in 2000 because of a higher average concentration of SO2 in 2002 than in 2000 and not because of the average dry deposition velocity which was lower for SO2 in 2002. Also,dry SO2 deposition was the dominant fraction of deposited atmospheric sulfur in forests, contributing over 69% of the total annual sulfur deposition. Thus, dry SO2 deposition should be considered when estimating sulfur balance in forest ecological systems.

  19. Scale formation in deluged dry cooling systems

    Energy Technology Data Exchange (ETDEWEB)

    Pratt, D.R.

    1976-05-01

    Deluging of air-cooled heat exchangers with water during warm periods holds the promise of increasing heat rejection capability and reducing the cost of dry cooling. One of the principal uncertainties in the use of the deluge concept is the tendency toward deposition of solids from the delugate. Small amounts of calcium carbonate scale may significantly reduce the cooling efficiency of a deluged system by reducing the heat transfer coefficient and interfering with delugate flow. Thus the question of delugate water quality is of major importance in evaluating scale formation and its effect on heat transfer in the deluged dry cooling system. The paper discusses, in relation to the deluged dry cooling system, the importance of scale prevention, the theory of scale formation and application of this theory to the deluged system, the problems of delugate evaporation, and delugate treatment required to prevent scaling.

  20. METALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    <正>20091594 Bao Yafan(The Third Geologic Survey of Jilin Province,Siping 136000,China);Liu Yanjun Relations between Bashenerxi Granite,West Dongkunlun and Baiganhu Tungsten-Tin Deposit(Jilin Geology,ISSN1001-2427,CN22-1099/P,27(3),2008,p.56-59,67,5 illus.,2 tables,7 refs.,with English abstract)Key words:tungsten ores,tin ores,monzogranite,Kunlun Mountains20091595 Chen Fuwen(Yichang Institute of Geology and Mineral Resources,China Geological Survey,Yichang 443003,China);Dai Pingyun Metallogenetic and Isotopic Chronological Study on the Shenjiaya Gold Deposit in Xuefeng Mountains,Hunan Province(Acta Geologica Sinica,ISSN0001-5717,CN11-1951/P,82(7),2008,p.906-911,3 illus.,2 tables,30 refs.)Key words:gold ores,HunanThe Shenjiaya gold deposit is a representative one

  1. Atmospheric Sulfur Deposition on Farmland in East China

    Institute of Scientific and Technical Information of China (English)

    WANG Ti-Jian; YANG Hao-Ming; GAO Li-Jie; ZHANG Yan; HU Zheng-Yi; XU Cheng-Kai

    2005-01-01

    Atmospheric sulfur deposition onto typical farmland in East China was investigated using both field measurements and numerical modeling. The field measurements were conducted at the Experiment Station of Red Soil Ecology, Chinese Academy of Sciences, 10 km from Yingtan, Jiangxi Province, East China, between November 1998 and October 1999, and at the Changshu Ecological Experiment Station, Chinese Academy of Sciences, in a rapidly developing region of Jiangsu Province, East China, between April 2001 and March 2002. The regional acid deposition model system (RegADMS), in which the dry deposition velocities of SO2 and sulfate aerosols (SO42-) were estimated using a big-leaf resistance analogy model, was applied to simulate air sulfur deposition over East China and sulfur deposition onto lands of different use types in East China. The wet scavenging coefficients were parameterized in terms of precipitation rate, and the effect of sub-grid processes due to inhomogeneous land use on dry deposition velocity was also included. Results of the field measurements showed that over 83% of the total sulfur deposition at the Yingtan site was dry deposition, while at the Changshu site42% was dry deposition. The total sulfur deposition was much larger at the Yingtan site than at the Changshu site, which suggested contrasting air pollution and meteorological situations. The modeling results revealed that the total annual sulfur deposition over East China was 1.88 Mt, of which 72.8% was deposited onto farmland, and dry deposition accounted for 43% of the total sulfur deposited. The modeling results were generally in agreement with those from the observations.Overall, this study suggested that atmospheric sulfur deposition played an important role in the soil sulfur balance, which could have a significant effect on agricultural ecosystems in the study region.

  2. METALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>20111705 An Junbo(Team 603,Bureau of Nonferrous Metals Geological Exploration of Jilin Province,Hunchun 133300,China);Xu Renjie Geological Features and Ore Genesis of Baishilazi Scheelite Deposit in Yanbian Area(Jilin Geology,ISSN1001-2427,CN22-1099/P,29(3),2010,p.39-43,2 illus.,2 tables,7 refs.)Key words:tungsten ores,Jilin ProvinceThe Baishilazi scheelite deposit is located in contacting zone between the marble of the Late Palaeozoic Qinglongcun Group and the Hercynian biotite granite.The vein and lenticular major ore body is obviously controlled by NE-extending faults and con

  3. Atmospheric nitrogen budget in Sahelian dry savannas

    Directory of Open Access Journals (Sweden)

    C. Delon

    2009-06-01

    Full Text Available The atmospheric nitrogen budget depends on emission and deposition fluxes both as reduced and oxidized nitrogen compounds. In this study, a first attempt at estimating the Sahel nitrogen budget for the year 2006 is made, through measurements and simulations at three stations from the IDAF network situated in dry savanna ecosystems. Dry deposition fluxes are estimated from measurements of NO2, HNO3 and NH3 gaseous concentrations, and wet deposition fluxes are calculated from NH4+ and NO3 concentrations in samples of rain. Emission fluxes are estimated including biogenic emission of NO from soils (an Artificial Neural Network module has been inserted into the ISBA-SURFEX surface model, emission of NOx and NH3 from domestic fires and biomass burning, and volatilization of NH3 from animal excreta.

    This study uses original and unique data from remote and hardly-ever-explored regions. The monthly evolution of oxidized N compounds shows that deposition increases at the beginning of the rainy season because of large emissions of biogenic NO (pulse events. Emission of oxidized compounds is dominated by biogenic emission from soils (domestic fires and biomass burning account for 27% at the most, depending on the station, whereas emission of NH3 is dominated by the process of volatilization. Deposition fluxes are dominated by gaseous dry deposition processes (58% of the total, for both oxidized and reduced compounds. The average deposition flux in dry savanna ecosystems ranges from 8.6 to 10.9 kgN ha−1 yr−1, with 30% attributed to oxidized compounds, and the other 70% attributed to NHx. The average emission flux ranges from 7.8 to 9.7 kgN ha−1 yr−1, dominated by NH3 volatilization (67% and biogenic emission from soils (24%. The annual budget is then

  4. METALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    <正>20090243 Chen Zhibin (Hebei Institute of Geological Survey, Shijiazhuang 050081, China) Ore-Controlling Factors of the Beichagoumen Ag-Polymetallic Deposits in Northern Hebei Province (Geological Survey and Research, ISSN1672-4135, CN12-1353/P, 31(1), 2008, p.1-5, 3 illus., 10 refs.)

  5. METALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>20131565 Cai Lianyou(No.332 Geological Team,Bureau of Geology and Mineral Resources Exploration of Anhui Province,Huangshan 245000,China);Weng Wangfei Geological Characteristics and Genesis Analysis of Guocun Navajoite Deposit in South Anhui Province(Mineral Resources and Geology,

  6. METALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    <正>20102341 Bao Peisheng(Institute of Geology,Chinese Academy of Geological Science,Beijing 100037,China)Further Discussion on the Genesis of the Podiform Chromite Deposits in the Ophiolites-Questioning about the Rock:Melt Interaction Metallogeny(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,28(12),2009,p.1741-1761

  7. NONMETALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>20131601 Gao Junbo(College of Resources and Environmental Engineering,Guizhou University,Guiyang 550003,China);Yang Ruidong Hydrothermal Venting-Flowing Sedimentation Characteristics of Devonian Barite Deposits from Leji,Zhenning County,Guizhou Province(Acta Sedimentologica Sinica,ISSN1000-0550,CN62-1038/P,30(3),

  8. Stripping with dry ice

    Science.gov (United States)

    Malavallon, Olivier

    1995-04-01

    Mechanical-type stripping using dry ice (solid CO2) consists in blasting particles of dry ice onto the painted surface. This surface can be used alone or in duplex according to type of substrate to be treated. According to operating conditions, three physical mechanisms may be involved when blasting dry ice particles onto a paint system: thermal shock, differential thermal contraction, and mechanical shock. The blast nozzle, nozzle travel speed, blast angle, stripping distance, and compressed air pressure and media flow rate influence the stripping quality and the uniformity and efficiency obtained.

  9. 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

  10. [Little Dry Creek Drainage

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Map of the drainage boundary, direction of flow, canals and ditches, and streets for the drainage study plan and profile for Little Dry Creek sub area in the North...

  11. What Is Dry Eye?

    Medline Plus

    Full Text Available ... information about eye health and preserving your vision. Privacy Policy Related New Dry Eye Treatment is a ... the Academy Financial Relationships with Industry Medical Disclaimer Privacy Policy Terms of Service For Advertisers For Media ...

  12. Cold Vacuum Drying Facility

    Data.gov (United States)

    Federal Laboratory Consortium — Located near the K-Basins (see K-Basins link) in Hanford's 100 Area is a facility called the Cold Vacuum Drying Facility (CVDF).Between 2000 and 2004, workers at the...

  13. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Pediatric Ophthalmology Education Center Oculofacial Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center Global Ophthalmology Guide Eye ... What Is Dry Eye? Leer en Español: ¿Qué ...

  14. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Dry Eye Symptoms Related Ask an Ophthalmologist Answers Can a six-month dissolvable punctal plug be removed ... insert a permanent punctal plug? Sep 12, 2017 Can you explain why I have halos and blurry ...

  15. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Pediatric Ophthalmology Education Center Oculofacial Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center Global Ophthalmology Guide ... What Is Dry Eye? Written By: Kierstan Boyd ...

  16. What Is Dry Eye?

    Medline Plus

    Full Text Available ... about eye health and preserving your vision. Privacy Policy Related New Dry Eye Treatment is a Tear- ... Academy Financial Relationships with Industry Medical Disclaimer Privacy Policy Terms of Service For Advertisers For Media Ophthalmology ...

  17. Electro-dry-adhesion.

    Science.gov (United States)

    Krahn, Jeffrey; Menon, Carlo

    2012-03-27

    This work presents novel conductive bioinspired dry adhesives with mushroom caps that enable the use of a synergistic combination of electrostatic and van der Waals forces (electro-dry-adhesion). An increase in shear adhesion bond strength of up to 2046% on a wide range of materials is measured when a maximum electrical field of 36.4 V μm(-1) is applied. A suction effect, due to the shape of the dry adhesive fibers, on overall adhesion was not noted for electro-dry-adhesives when testing was performed at both atmospheric and reduced pressure. Utilization of electrostatics to apply a preloading force to dry adhesive fiber arrays allows increased adhesion even after electrostatic force generation has been halted by ensuring the close contact necessary for van der Waals forces to be effective. A comparison is made between self-preloading of the electro-dry-adhesives and the direct application of a normal preloading pressure resulting in nearly the same shear bond strength with an applied voltage of 3.33 kV on the same sample.

  18. 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...

  19. 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...

  20. Mechanical Details for Construction of a Dry Aerosol Deposition Device

    Science.gov (United States)

    2014-07-22

    DISTRIBUTION/AVAILABILITY STATEMENT 13. SUPPLEMENTARY NOTES 14. ABSTRACT 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: a. REPORT b. ABSTRACT...mechanism for rapid and highly reproducible loading of microorganisms onto surfaces. The DADD was tested with Bacillus atrophaeus spores and

  1. Autochthonous "Bjelovars dried cheese"

    Directory of Open Access Journals (Sweden)

    Slavko Kirin

    2006-12-01

    Full Text Available «Dried cheese» is in autochthonous group of Bjelovar region cheeses which is still produced in rural domestic scale. The name of cheese originates from production procedure - drying for longer or shorter period in airy place after which the cheese is smoked, or is smoked only without drying. This type of cheese is produced in whole central region of Croatia which includes Međimurje, Podravina, Bilogora; Moslavina, Posavina and region around the capital. The aim of this paper is to describe and determine sensory, chemical and microbiological composition to determine its characteristics and production standards. As standards for sensory properties following characteristics can be used: a Outer shape: dimensions: diameter: 140-145 mm, height: 58-61 mm, mass: 700-750 g, equal, rounded shape, smooth skin, equal colour; b Consistency: easily cut, elastic, soft; c Cut: nicely combined white body, few improper holes of equal size; d Odour: pleasant milky acid odour, fairly smoky; e Taste: Fairly milky acidic taste, medium salty, fairly smoky taste. Depending on fat in dry matter content and water content in non fat dry matter, analyzed samples can be characterized as quarter fat, soft and semidry cheese. Higher acidity and saltiness was determined in some samples, microbiological analyses has shown that the most common contaminants are yeasts and moulds.

  2. Drying of Malaysian Capsicum annuum L. (Red Chili) Dried by Open and Solar Drying

    OpenAIRE

    Ahmad Fudholi; Mohd Yusof Othman; Mohd Hafidz Ruslan; Kamaruzzaman Sopian

    2013-01-01

    This study evaluated the performance of solar drying in the Malaysian red chili (Capsicum annuum L.). Red chilies were dried down from approximately 80% (wb) to 10% (wb) moisture content within 33 h. The drying process was conducted during the day, and it was compared with 65 h of open sun drying. Solar drying yielded a 49% saving in drying time compared with open sun drying. At the average solar radiation of 420 W/m2 and air flow rate of 0.07 kg/s, the collector, drying system, and pickup de...

  3. METALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>20122389 Cai Lianyou ( No.332 Geological Team,Bureau of Geology and Mineral Resources Exploration of Anhui Province,Huangshan 245000,China );Weng Wangfei Geologic Characteristic and Ore-Control Factors of the Nanshan W-Mo Polymetallic Ore Deposit in South Anhui Province ( Geological Survey and Research,ISSN1672-4135,CN12-1353 / P,34 ( 4 ), 2011,p.290-298,3 illus.,1table,14refs. ) Key words:tungsten ores,molybdenum ores,ore guide of prospecting,Anhui Province

  4. METALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>20110165 Chen Jiawei(The 3rd Geological Team,Henan Bureau of Geology and Mineral Resources,Xinyang 464000,China)Ore Control Conditions and Genetic Model for the Bodaoling Ag-Au Deposit in Guangshan,Henan Province(Acta Geologica Sichuan,ISSN1006-0995,CN51-1273/P,30(1),2010,p.28-30,5 illus.,1 ref.,with English abstract)Key words:gold ores,Henan Province20110166 Chen Mingquan(Geological Team 306,Yunnan Bureau of Nonferrous Geology,Kunming 650216,Ch

  5. Drying of Concrete

    DEFF Research Database (Denmark)

    Hansen, Kurt Kielsgaard; Geiker, Mette Rica; Nygaard, Peter Vagn;

    2002-01-01

    Estimated and measured relative humidity (RH) change during drying are compared for two concretes, 1: w/c=0.46 and 2: w/(c+0.5fa+2sf)=0.50. The estimations were undertaken by means of the Swedish program TorkaS 1.0. Measurements were performed by RH-sensors type Humi-Guard. Drying of 150 mm thick...... samples from sides at 60% RH and 22 °C took place from 4 to 56 days after casting. At the end of the drying period the measured RH was about 4% lower than the estimated RH at 1/5th depth from the exposed surface for both concretes. In the middle of the samples, the measured RH of concretes 1 and 2 were 2...

  6. Drying of Concrete

    DEFF Research Database (Denmark)

    Hansen, Kurt Kielsgaard; Geiker, Mette Rica; Nygaard, Peter Vagn

    2002-01-01

    Estimated and measured relative humidity (RH) change during drying are compared for two concretes, 1: w/c=0.46 and 2: w/(c+0.5fa+2sf)=0.50. The estimations were undertaken by means of the Swedish program TorkaS 1.0. Measurements were performed by RH-sensors type Humi-Guard. Drying of 150 mm thick...... samples from sides at 60% RH and 22 °C took place from 4 to 56 days after casting. At the end of the drying period the measured RH was about 4% lower than the estimated RH at 1/5th depth from the exposed surface for both concretes. In the middle of the samples, the measured RH of concretes 1 and 2 were 2...

  7. Trigger Point Dry Needling.

    Science.gov (United States)

    2017-03-01

    Increasingly, physical therapists in the United States and throughout the world are using dry needling to treat musculoskeletal pain, even though this treatment has been a controversial addition to practice. To better generalize to physical therapy practice the findings about dry needling thus far, the authors of a study published in the March 2017 issue of JOSPT identified the need for a systematic review examining the effectiveness of dry needling performed by physical therapists on people with musculoskeletal pain. Their review offers a meta-analysis of data from several included studies and assesses the evidence for risks of bias. J Orthop Sports Phys Ther 2017;47(3):150. doi:10.2519/jospt.2017.0502.

  8. Magnetically responsive dry fluids

    Science.gov (United States)

    Sousa, Filipa L.; Bustamante, Rodney; Millán, Angel; Palacio, Fernando; Trindade, Tito; Silva, Nuno J. O.

    2013-07-01

    Ferrofluids and dry magnetic particles are two separate classes of magnetic materials with specific niche applications, mainly due to their distinct viscosity and interparticle distances. For practical applications, the stability of these two properties is highly desirable but hard to achieve. Conceptually, a possible solution to this problem would be encapsulating the magnetic particles but keeping them free to rotate inside a capsule with constant interparticle distances and thus shielded from changes in the viscosity of the surrounding media. Here we present an example of such materials by the encapsulation of magnetic ferrofluids into highly hydrophobic silica, leading to the formation of dry ferrofluids, i.e., a material behaving macroscopically as a dry powder but locally as a ferrofluid where magnetic nanoparticles are free to rotate in the liquid.Ferrofluids and dry magnetic particles are two separate classes of magnetic materials with specific niche applications, mainly due to their distinct viscosity and interparticle distances. For practical applications, the stability of these two properties is highly desirable but hard to achieve. Conceptually, a possible solution to this problem would be encapsulating the magnetic particles but keeping them free to rotate inside a capsule with constant interparticle distances and thus shielded from changes in the viscosity of the surrounding media. Here we present an example of such materials by the encapsulation of magnetic ferrofluids into highly hydrophobic silica, leading to the formation of dry ferrofluids, i.e., a material behaving macroscopically as a dry powder but locally as a ferrofluid where magnetic nanoparticles are free to rotate in the liquid. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr01784b

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

    CERN Document Server

    Boulogne, François; Stone, Howard A

    2016-01-01

    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 dynamic...

  10. Properties of Spray Dried Food and Spray Drying Characteristics

    Science.gov (United States)

    Katoh, Fumio

    The following conclusions are obtained, studying properties of spray dried food and drying characteristics. (a) Dried particles are similar to spray droplets in size distribution (y=2.5), and particle count distribution is arranged as (dn/dx = ae-bx). (b) The ratio of the particle diameters before and after drying is calculated with moisture before and after drying, and porosity is given as (εp = ww4). (c) The standard drying method is presented to evaluate accurately drying problems at a certain standard. (d) Equilibrium moisture at 20 up to 100°C are summarized in terms of adsorption potential. (e) It makes clear that calulation based on the theory of residence time and drying time represents well complex spray drying characteristics.

  11. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Tips & Prevention News Ask an Ophthalmologist Patient Stories Español Eye Health / Eye Health A-Z Dry Eye ... when I sleep? Feb 10, 2016 Leer en Español: ¿Qué Es el Ojo Seco? Find an Ophthalmologist ...

  12. Biogeochemical stoichiometry of Antarctic Dry Valley ecosystems

    Science.gov (United States)

    Barrett, J. E.; Virginia, R. A.; Lyons, W. B.; McKnight, D. M.; Priscu, J. C.; Doran, P. T.; Fountain, A. G.; Wall, D. H.; Moorhead, D. L.

    2007-03-01

    Among aquatic and terrestrial landscapes of the McMurdo Dry Valleys, Antarctica, ecosystem stoichiometry ranges from values near the Redfield ratios for C:N:P to nutrient concentrations in proportions far above or below ratios necessary to support balanced microbial growth. This polar desert provides an opportunity to evaluate stoichiometric approaches to understand nutrient cycling in an ecosystem where biological diversity and activity are low, and controls over the movement and mass balances of nutrients operate over 10-106 years. The simple organisms (microbial and metazoan) comprising dry valley foodwebs adhere to strict biochemical requirements in the composition of their biomass, and when activated by availability of liquid water, they influence the chemical composition of their environment according to these ratios. Nitrogen and phosphorus varied significantly in terrestrial and aquatic ecosystems occurring on landscape surfaces across a wide range of exposure ages, indicating strong influences of landscape development and geochemistry on nutrient availability. Biota control the elemental ratio of stream waters, while geochemical stoichiometry (e.g., weathering, atmospheric deposition) evidently limits the distribution of soil invertebrates. We present a conceptual model describing transformations across dry valley landscapes facilitated by exchanges of liquid water and biotic processing of dissolved nutrients. We conclude that contemporary ecosystem stoichiometry of Antarctic Dry Valley soils, glaciers, streams, and lakes results from a combination of extant biological processes superimposed on a legacy of landscape processes and previous climates.

  13. A dry electrode for EEG recording.

    Science.gov (United States)

    Taheri, B A; Knight, R T; Smith, R L

    1994-05-01

    This paper describes the design, fabrication and testing of a prototype dry surface electrode for EEG signal recording. The new dry electrode has the advantages of no need for skin preparation or conductive paste, potential for reduced sensitivity to motion artifacts and an enhanced signal-to-noise ratio. The electrode's sensing element is a 3 mm stainless steel disk which has a 2000 A (200 nm) thick nitride coating deposited onto one side. The back side of the disk is attached to an impedance converting amplifier. The prototype electrode was mounted on a copper plate attached to the scalp by a Velcro strap. The performance of this prototype dry electrode was compared to commercially available wet electrodes in 3 areas of electroencephalogram (EEG) recording: (1) spontaneous EEG, (2) sensory evoked potentials, and (3) cognitive evoked potentials. In addition to the raw EEG, the power spectra of the signals from both types of electrodes were also recorded. The results suggest that the dry electrode performs comparably to conventional electrodes for all types of EEG signal analysis. This new electrode may be useful for the production of high resolution surface maps of brain activity where a large number of electrodes or prolonged recording times are required.

  14. Infrared Drying Parameter Optimization

    Science.gov (United States)

    Jackson, Matthew R.

    In recent years, much research has been done to explore direct printing methods, such as screen and inkjet printing, as alternatives to the traditional lithographic process. The primary motivation is reduction of the material costs associated with producing common electronic devices. Much of this research has focused on developing inkjet or screen paste formulations that can be printed on a variety of substrates, and which have similar conductivity performance to the materials currently used in the manufacturing of circuit boards and other electronic devices. Very little research has been done to develop a process that would use direct printing methods to manufacture electronic devices in high volumes. This study focuses on developing and optimizing a drying process for conductive copper ink in a high volume manufacturing setting. Using an infrared (IR) dryer, it was determined that conductive copper prints could be dried in seconds or minutes as opposed to tens of minutes or hours that it would take with other drying devices, such as a vacuum oven. In addition, this study also identifies significant parameters that can affect the conductivity of IR dried prints. Using designed experiments and statistical analysis; the dryer parameters were optimized to produce the best conductivity performance for a specific ink formulation and substrate combination. It was determined that for an ethylene glycol, butanol, 1-methoxy 2- propanol ink formulation printed on Kapton, the optimal drying parameters consisted of a dryer height of 4 inches, a temperature setting between 190 - 200°C, and a dry time of 50-65 seconds depending on the printed film thickness as determined by the number of print passes. It is important to note that these parameters are optimized specifically for the ink formulation and substrate used in this study. There is still much research that needs to be done into optimizing the IR dryer for different ink substrate combinations, as well as developing a

  15. Quality of dry ginger (Zingiber officinale) by different drying methods.

    Science.gov (United States)

    E, Jayashree; R, Visvanathan; T, John Zachariah

    2014-11-01

    Ginger rhizomes sliced to various lengths of 5, 10, 15, 20, 30, 40, 50 mm and whole rhizomes were dried from an initial moisture content of 81.3 % to final moisture content of less than 10 % by various drying methods like sun drying, solar tunnel drying and cabinet tray drying at temperatures of 50, 55, 60 and 65 °C. Slicing of ginger rhizomes significantly reduced the drying time of ginger in all the drying methods. It was observed that drying of whole ginger rhizomes under sun took the maximum time (9 days) followed by solar tunnel drying (8 days). Significant reduction in essential oil and oleoresin content of dry ginger was found as the slice length decreased. The important constituents of ginger essential oil like zingiberene, limonene, linalool, geraniol and nerolidol as determined using a gas chromatography was also found to decrease during slicing and as the drying temperature increased. The pungency constituents in the oleoresin of ginger like total gingerols and total shogoals as determined using a reverse phase high performance liquid chromatography also showed a decreasing trend on slicing and with the increase in drying temperature. It was observed from the drying studies that whole ginger rhizomes dried under sun drying or in a solar tunnel drier retained the maximum essential oil (13.9 mg/g) and oleoresin content (45.2 mg/g) of dry ginger. In mechanical drying, the drying temperature of 60 °C was considered optimum however there was about 12.2 % loss in essential oil at this temperature.

  16. Dry release of all-polymer structures

    DEFF Research Database (Denmark)

    Haefliger, D.; Nordstrøm, M.; Rasmussen, Peter Andreas

    2005-01-01

    We present a simple dry release technique which uses a thin fluorocarbon film for efficient removal of plastic microdevices from a mould or a handling substrate by reducing the adhesion between the two. This fluorocarbon film is deposited on the substrate in an advanced Si dry etch device utilising...... the C4F8 passivation plasma. Micromachined polymer chips made of SU-8 are removed from the handling substrate by lifting them off using mechanical tweezers. Effective release of chips of several mm(2) size within a few seconds and the lift-off of fragile, 5.5-mu m-thin cantilevers at a yield of almost...... 100% were demonstrated on wafer-scale. The fluorocarbon film showed excellent compatibility with metal etch processes and polymer baking and curing steps. It further facilitates demoulding of polydimethylsiloxane stamps suitable for soft-lithography....

  17. Properties of electrodeposited amorphous Fe-Ni-W alloy deposits

    Institute of Scientific and Technical Information of China (English)

    HE Feng-jiao; WANG Miao; LU Xin

    2006-01-01

    A new technique of electroplating amorphous Fe-Ni-W alloy deposits was proposed. The structure and morphology of Fe-Ni-W alloy deposit were detected by XRD and SEM. The friction and wear behavior of Fe-Ni-W alloy deposit were studied and compared with that of chromium deposit. The corrosion properties against 5% sodium chloride, 5% sulfuric acid and 5% sodium hydroxide were also discussed. The experimental results indicate that Fe-Ni-W alloy deposits have superior properties against wear than hard chromium deposits under dry sliding condition. Under oil sliding condition, except their better wear resistance, the deposits can protect their counterparts against wear. The deposits plated on brass and AISI 1045 steel show good behavior against corrosion of 5% sodium chloride, 5% sulfuric acid and 5% sodium hydroxide. The bath of electroplating amorphous Fe-Ni-W alloy deposits is environmentally friendly and would find widely use in industry.

  18. OXIDATION OF DRY HYDROCARBONS AT HIGH-POWER DENSITY ANODES

    Energy Technology Data Exchange (ETDEWEB)

    K.Krist; O. Spaldon-Stewart; R. Remick

    2004-03-01

    This work builds upon discoveries by the University of Pennsylvania and others pertaining to the oxidation of dry hydrocarbon fuels in high temperature solid oxide fuel cells. The work reported here was restricted primarily to dry methane and confirms that YSZ-based cells, having ceria in the anode as a catalyst and copper in the anode as a current collector, can operate on dry methane for extended periods. Thirty-three lab-scale cells of various designs were fabricated and operated under a variety of conditions. The longest-lived cell gave stable performance on dry methane at 800 C for over 305 hours. Only slight carbon deposition was noted at the completion of the test. A corresponding nickel/YSZ-based anode would have lasted for less than an hour under these test conditions (which included open circuit potential measurements) before carbon fouling essentially destroyed the cell. The best performing cell achieved 112 mW/cm{sub 2} on dry methane at 800 C. Several problems were encountered with carbon fouling and declining open circuit voltages in many of the test cells after switching from operation on hydrogen to dry methane. Although not rigorously confirmed by experimentation, the results suggested that air infiltration through less than perfect perimeter seals or pinholes in the electrolytes, or both gave rise to conditions that caused the carbon fouling and OCV decline. Small amounts of air reacting with methane in a partial oxidation reaction could produce carbon monoxide that, in turn, would deposit the carbon. If this mechanism is confirmed, it implies that near perfect hardware is required for extended operation. Some evidence was also found for the formation of electrical shorts, probably from carbon deposits bridging the electrolyte. Work with odorized methane and with methane containing 100-ppm hydrogen sulfide confirmed that copper is stable at 800 C in dry hydrocarbon fuels in the presence of sulfur. In a number of cases, but not exclusively, the

  19. NONMETALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>20111761 Chen Hua(115 Geological Party,Guizhou Bureau of Geology and Mineral Exploration & Development,Guiyang 551400,China);Deng Chao Analysis on the Metallogenic Environment of Maochang Bauxite in Guizhou Province(Guizhou Geology,ISSN1000-5943,CN52-1059/P,27(3),2010,p.198-201,2 illus.,1 table,8 refs.)Key words:bauxite deposit,Guizhou Province By long time physical and chemical process,the carbonate rock after Central Guizhou uplidft,becomes red clay,after further weathering,the red clay decomposed into the oxide,hydroxide of Al and Fe,in the dissolution hole and depression,it concentrates primary fragmentary tight and earthy karst bauxite ore.Because the variation of landform,it decomposes and cracks again,affords the material source

  20. Dry powder formulation in the twincertm for bronchial challenge testing

    NARCIS (Netherlands)

    Lexmond, A.J.; Hagedoorn, P.; Frijlink, H.W.; Ten Hacken, N.H.T.; Steckel, H.; De Boer, A.H.

    2013-01-01

    Summary Background: In bronchial challenge testing lung deposition of the stimulus may be poorly controlled due to incorrect use of nebulisers. Furthermore, the need for freshly prepared solutions burdens personnel and budget. In this study we aim to develop a dry powder alternative with higher repr

  1. Study on drying rate in contact drying with flexible screen

    Institute of Scientific and Technical Information of China (English)

    王伟宏; 陆仁书; 张显权

    2000-01-01

    The moisture contents (MC) of popular veneers were tested in Composition Board Laboratory of Northeast Forestry University by contact drying with flexible screen. The influence factors considered included temperature, initial moisture contents (IMC), and veneer thickness. Veneer-drying laws under different hot press conditions were analyzed. The results showed that the drying rate increased with temperature rising. 160℃ was considered to be more efficient than 140℃ and 180℃ because excessive high temperature has no significant contribution to drying rate. IMC had significant effect on drying rate. The veneer with high IMC had a higher drying rate at above fiber saturation point (FSP) and a lower drying rate at below FSP, compared to the veneer with low IMC. Average drying rate also varied with thickness in power law.

  2. Dry alcohol 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 dry alcohol production 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 with a capacity of 40 m3/y was manufactured, at "Zorka Pharma", Šabac in 1995-1996. The product meets all quality demands, as well as environmental regulations. The dry alcohol production process is fully automatized. There is no waste in the process, neither gaseous, nor liquid. The chosen process provides safe operation according to temperature regime and resistance in the pipes, air purification columns and filters. Working at increased pressure is suitable for evaporation and condensation at increased temperatures. The production process can be controlled manually, which is necessary during start-up, and repairs.

  3. An unusually dry story

    Directory of Open Access Journals (Sweden)

    Srinivas Rajagopala

    2015-01-01

    Full Text Available We present a middle-aged woman with a prior history of central nervous system (CNS demyelinating disorder who presented with an acute onset quadriparesis and respiratory failure. The evaluation revealed distal renal tubular acidosis with hypokalemia and medullary nephrocalcinosis. Weakness persisted despite potassium correction, and ongoing evaluation confirmed recurrent CNS and long-segment spinal cord demyelination with anti-aquaporin-4 antibodies. There was no history of dry eyes or dry mouth. Anti-Sjogren′s syndrome A antigen antibodies were elevated, and there was reduced salivary flow on scintigraphy. Coexistent antiphospholipid antibody syndrome with inferior vena cava thrombosis was also found on evaluation. The index patient highlights several rare manifestations of primary Sjogren′s syndrome (pSS as the presenting features and highlights the differential diagnosis of the clinical syndromes in which pSS should be considered in the Intensive Care Unit.

  4. Drying characteristics and kinetics of fluidized bed dried potato

    OpenAIRE

    S.B. BAKAL; K.H. GEDAM; Sharma, G. P.

    2008-01-01

    In developed countries, more than 50% potatoes are consumed as processed products. As drying is the vital phenomenon in processing, it is necessary to investigate the drying characteristics and its kinetics. In this experimental study, drying kinetics of Potato in two different shape of cuboidal & cylindrical with three aspect ratio was investigated as a function of drying conditions. Experiments were conducted using air temperatures of 50, 60 and 70 ºC, at velocity of 7 ms-1. The experimenta...

  5. Dry Eye Syndrome

    Directory of Open Access Journals (Sweden)

    Mohammad-Ali Javadi

    2011-01-01

    Full Text Available Our understanding of keratoconjunctivitis sicca (KCS, also known as dry eye syndrome, has been changed over recent years. Until lately, the condition was thought to be merely due to aqueous tear insufficiency. Today, it is understood that KCS is a multifactorial disorder due to inflammation of the ocular surface and lacrimal gland, neurotrophic deficiency and meibomian gland dysfunction. This change in paradigm has led to the development of new and more effective medications.

  6. Drying of complex suspensions

    OpenAIRE

    Xu, Lei; Bergés, Alexis; Lu, Peter J.; Studart, André R.; Schofield, Andrew B.; Oki, Hidekazu; Davies, Simon; Weitz, David A.

    2010-01-01

    We investigate the 3D structure and drying dynamics of complex mixtures of emulsion droplets and colloidal particles, using confocal microscopy. Air invades and rapidly collapses large emulsion droplets, forcing their contents into the surrounding porous particle pack at a rate proportional to the square of the droplet radius. By contrast, small droplets do not collapse, but remain intact and are merely deformed. A simple model coupling the Laplace pressure to Darcy's law correctly estimates ...

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

    Directory of Open Access Journals (Sweden)

    W. Xu

    2015-07-01

    Full Text Available 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.

  8. Dry mouth during cancer treatment

    Science.gov (United States)

    ... gov/ency/patientinstructions/000032.htm Dry mouth during cancer treatment To use the sharing features on this page, please enable JavaScript. Some cancer treatments and medicines can cause dry mouth. Symptoms you ...

  9. Nitramine Drying & Fine Grinding Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Nitramine Drying and Fine Grinding Facility provides TACOM-ARDEC with a state-of-the-art facility capable of drying and grinding high explosives (e.g., RDX and...

  10. Total atmospheric mercury deposition in forested areas in South Korea

    Science.gov (United States)

    Han, Jin-Su; Seo, Yong-Seok; Kim, Moon-Kyung; Holsen, Thomas M.; Yi, Seung-Muk

    2016-06-01

    In this study, mercury (Hg) was sampled weekly in dry and wet deposition and throughfall and monthly in litterfall, and as it was volatilized from soil from August 2008 to February 2010 to identify the factors influencing the amount of atmospheric Hg deposited to forested areas in a temperate deciduous forest in South Korea. For this location there was no significant correlation between the estimated monthly dry deposition flux (litterfall + throughfall - wet deposition) (6.7 µg m-2 yr-1) and directly measured dry deposition (9.9 µg m-2 yr-1) likely due primarily to Hg losses from the litterfall collector. Dry deposition fluxes in cold seasons (fall and winter) were lower than in warmer seasons (spring and summer). The volume-weighted mean (VWM) Hg concentrations in both precipitation and throughfall were highest in winter, likely due to increased scavenging by snow events. Since South Korea experiences abundant rainfall in summer, VWM Hg concentrations in summer were lower than in other seasons. Litterfall fluxes were highest in the late fall to early winter, when leaves were dropped from the trees (September to November). The cumulative annual Hg emission flux from soil was 6.8 µg m-2 yr-1. Based on these data, the yearly deposition fluxes of Hg calculated using two input approaches (wet deposition + dry deposition or throughfall + litterfall) were 6.8 and 3.6 µg m-2 yr-1, respectively. This is the first reported study which measured the amount of atmospheric Hg deposited to forested areas in South Korea, and thus our results provide useful information to compare against data related to Hg fate and transport in this part of the world.

  11. 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.

  12. 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.

  13. Terrestrial Planets Accreted Dry

    Science.gov (United States)

    Albarede, F.; Blichert-Toft, J.

    2007-12-01

    Plate tectonics shaped the Earth, whereas the Moon is a dry and inactive desert. Mars probably came to rest within the first billion years of its history, and Venus, although internally very active, has a dry inferno for its surface. The strong gravity field of a large planet allows for an enormous amount of gravitational energy to be released, causing the outer part of the planetary body to melt (magma ocean), helps retain water on the planet, and increases the pressure gradient. The weak gravity field and anhydrous conditions prevailing on the Moon stabilized, on top of its magma ocean, a thick buoyant plagioclase lithosphere, which insulated the molten interior. On Earth, the buoyant hydrous phases (serpentines) produced by reactions between the terrestrial magma ocean and the wet impactors received from the outer Solar System isolated the magma and kept it molten for some few tens of million years. The elemental distributions and the range of condensation temperatures show that the planets from the inner Solar System accreted dry. The interior of planets that lost up to 95% of their K cannot contain much water. Foundering of their wet surface material softened the terrestrial mantle and set the scene for the onset of plate tectonics. This very same process may have removed all the water from the surface of Venus 500 My ago and added enough water to its mantle to make its internal dynamics very strong and keep the surface very young. Because of a radius smaller than that of the Earth, not enough water could be drawn into the Martian mantle before it was lost to space and Martian plate tectonics never began. The radius of a planet therefore is the key parameter controlling most of its evolutional features.

  14. Electrohydrodynamic drying of carrot slices.

    Directory of Open Access Journals (Sweden)

    Changjiang Ding

    Full Text Available Carrots have one of the highest levels of carotene, and they are rich in vitamins, fiber and minerals. However, since fresh carrots wilt rapidly after harvest under inappropriate storage conditions, drying has been used to improve their shelf life and retain nutritional quality. Therefore, to further investigate the potential of this method, carrot slices were dried in an EHD system in order to study the effect of different voltages on drying rate. As measures of quality, carotene content and rehydration ratio were, respectively, compared against the conventional oven drying regime. Carotene, the main component of the dried carrot, and rehydration characteristics of the dried product can both indicate quality by physical and chemical changes during the drying process. Mathematical modeling and simulation of drying curves were also performed, using root mean square error, reduced mean square of the deviation and modeling efficiency as the primary criteria to select the equation that best accounts for the variation in the drying curves of the dried samples. Theoretically, the Page model was best suited for describing the drying rate curve of carrot slices at 10kV to 30kV. Experimentally, the drying rate of carrots was notably greater in the EHD system when compared to control, and quality, as determined by carotene content and rehydration ratio, was also improved when compared to oven drying. Therefore, this work presents a facile and effective strategy for experimentally and theoretically determining the drying properties of carrots, and, as a result, it provides deeper insight into the industrial potential of the EHD drying technique.

  15. Dry EEG Electrodes

    Directory of Open Access Journals (Sweden)

    M. A. Lopez-Gordo

    2014-07-01

    Full Text Available Electroencephalography (EEG emerged in the second decade of the 20th century as a technique for recording the neurophysiological response. Since then, there has been little variation in the physical principles that sustain the signal acquisition probes, otherwise called electrodes. Currently, new advances in technology have brought new unexpected fields of applications apart from the clinical, for which new aspects such as usability and gel-free operation are first order priorities. Thanks to new advances in materials and integrated electronic systems technologies, a new generation of dry electrodes has been developed to fulfill the need. In this manuscript, we review current approaches to develop dry EEG electrodes for clinical and other applications, including information about measurement methods and evaluation reports. We conclude that, although a broad and non-homogeneous diversity of approaches has been evaluated without a consensus in procedures and methodology, their performances are not far from those obtained with wet electrodes, which are considered the gold standard, thus enabling the former to be a useful tool in a variety of novel applications.

  16. Solar drying and agribusiness

    Directory of Open Access Journals (Sweden)

    Sebastiana del Monserrate Ruiz Cedeño

    2016-07-01

    Full Text Available Agribusinesses are the livelihoods of rural populations, but when production increase, many products are damaged and lose their commercial value due to lack of conservation treatments at a local level. Agricultural production represents the foundation of economic development of the province of Manabi. A significant level of agricultural products is lost due to lack of conservation technologies. Solar drying is a way of conserving by dehydration of some products such as: vegetables, fruits, aromatic and medicinal plants. This can be achieved by a process of proper conservation that is conducive to reduce losses using technologies easy to build, as are the different types of solar dryers which are already used in different parts of the South American region. This article proposes to introduce solar-drying technology in agricultural areas of the province of Manabi. And thereby achieve the regaining of different products that today are lost, incorporating new and attractive, marketable lines based on agricultural products naturally dehydrated with a high nutritionalvalue, capable of contributing to human health not only in the province but also in the country.

  17. 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.

  18. Base cation deposition in Europe - Part I. Model description, results and uncertainties

    NARCIS (Netherlands)

    Draaijers, G.P.J.; Leeuwen, E.P. van; Jong, P.G.H. de; Erisman, J.W.

    1997-01-01

    Deposition of base cations (Na+, Mg2+, Ca2+, K+) in Europe was mapped for 1989 with a spatial resolution of 10 x 20 km using the so-called inferential modeling technique. Deposition fields resembled the geographic variability of sources, land-use and climate. Dry deposition constituted on average 45

  19. ECONOMIC GEOLOGY (2)NONMETALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    <正>20071073 Huang Tiedong(No.1 Geological Team of Xinjiang Bureau of Exploration and Mining,Changji,Xinjiang 831100,China) Formation of the Salt Lake and KNO3 Ore in the Kumishi Block-Falling Basin in Xin- jiang(Hydrogeology & Engineering Geology, ISSN1000-3665,CN11-2202/P,32(6), 2005,p.20-24,4 illus.,3 tables,8 refs.) Key words:niter,salt deposits,Xinjiang The Kumishi Basin,a Cenozoic block- falling basin,has been controlled by a dry continental climate and continuously under- went a concentration process due to evapora- tion.The rock salt began to form in the late Pliocene to Pleistocene(35 ka B.P.).The thick rock salt bodies assembled in the late Holocene(4.5 ka B.P.)because of the stable crust and the continuous dry climate.With the evolution into the dry salt lake stage,the brines occurring in the crystals further con- centrated and the liquid-phase KNO3 formed,which is overlain by K-rich rock salt.

  20. Deposition parameterizations for the Industrial Source Complex (ISC3) model

    Energy Technology Data Exchange (ETDEWEB)

    Wesely, Marvin L. [Argonne National Lab. (ANL), Argonne, IL (United States); Doskey, Paul V. [Argonne National Lab. (ANL), Argonne, IL (United States); Shannon, J. D. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2002-06-01

    Improved algorithms have been developed to simulate the dry and wet deposition of hazardous air pollutants (HAPs) with the Industrial Source Complex version 3 (ISC3) model system. The dry deposition velocities (concentrations divided by downward flux at a specified height) of the gaseous HAPs are modeled with algorithms adapted from existing dry deposition modules. The dry deposition velocities are described in a conventional resistance scheme, for which micrometeorological formulas are applied to describe the aerodynamic resistances above the surface. Pathways to uptake at the ground and in vegetative canopies are depicted with several resistances that are affected by variations in air temperature, humidity, solar irradiance, and soil moisture. The role of soil moisture variations in affecting the uptake of gases through vegetative plant leaf stomata is assessed with the relative available soil moisture, which is estimated with a rudimentary budget of soil moisture content. Some of the procedures and equations are simplified to be commensurate with the type and extent of information on atmospheric and surface conditions available to the ISC3 model system user. For example, standardized land use types and seasonal categories provide sets of resistances to uptake by various components of the surface. To describe the dry deposition of the large number of gaseous organic HAPS, a new technique based on laboratory study results and theoretical considerations has been developed providing a means of evaluating the role of lipid solubility in uptake by the waxy outer cuticle of vegetative plant leaves.

  1. Dry aging of beef; Review.

    Science.gov (United States)

    Dashdorj, Dashmaa; Tripathi, Vinay Kumar; Cho, Soohyun; Kim, Younghoon; Hwang, Inho

    2016-01-01

    The present review has mainly focused on the specific parameters including aging (aging days, temperature, relative humidity, and air flow), eating quality (flavor, tenderness and juiciness), microbiological quality and economic (shrinkage, retail yields and cost) involved beef dry aging process. Dry aging is the process where beef carcasses or primal cuts are hanged and aged for 28 to 55 d under controlling environment conditions in a refrigerated room with 0° to 4 °C and with relative humidity of 75 to 80 %. However there are various opinions on dry aging procedures and purveyors of such products are passionate about their programs. Recently, there has been an increased interest in dry aging process by a wider array of purveyors and retailers in the many countries. Dry aging process is very costly because of high aging shrinkage (6 to15 %), trims loss (3 to 24 %), risk of contamination and the requirement of highest grades meat with. The packaging in highly moisture-permeable bag may positively impact on safety, quality and shelf stability of dry aged beef. The key effect of dry aging is the concentration of the flavor that can only be described as "dry-aged beef". But the contribution of flavor compounds of proteolysis and lipolysis to the cooked dry aged beef flavor is not fully known. Also there are limited scientific studies of aging parameters on the quality and palatability of dry aged beef.

  2. Dry ice blasting

    Science.gov (United States)

    Lonergan, Jeffrey M.

    1992-04-01

    As legal and societal pressures against the use of hazardous waste generating materials has increased, so has the motivation to find safe, effective, and permanent replacements. Dry ice blasting is a technology which uses CO2 pellets as a blasting medium. The use of CO2 for cleaning and stripping operations offers potential for significant environmental, safety, and productivity improvements over grit blasting, plastic media blasting, and chemical solvent cleaning. Because CO2 pellets break up and sublime upon impact, there is no expended media to dispose of. Unlike grit or plastic media blasting which produce large quantities of expended media, the only waste produced by CO2 blasting is the material removed. The quantity of hazardous waste produced, and thus the cost of hazardous waste disposal is significantly reduced.

  3. Dried fruit and dental health.

    Science.gov (United States)

    Sadler, Michèle Jeanne

    2016-12-01

    A comprehensive review of the literature has found that the common perceptions that dried fruits are "sticky", adhere to teeth, and are detrimental to dental health on account of their sugar content are based on weak evidence. There is a lack of good quality scientific data to support restrictive advice for dried fruit intake on the basis of dental health parameters and further research is required. A number of potentially positive attributes for dental health, such as the need to chew dried fruits which encourages salivary flow, and the presence of anti-microbial compounds and of sorbitol, also require investigation to establish the extent of their effects and whether they balance against any potentially negative attributes of dried fruit. Advice on dried fruit consumption should also take account of the nutritional benefits of dried fruit, being high in fibre, low in fat and containing useful levels of micronutrients.

  4. Nitrogen deposition in California forests: a review.

    Science.gov (United States)

    Bytnerowicz, A; Fenn, M E

    1996-01-01

    Atmospheric concentrations and deposition of the major nitrogenous (N) compounds and their biological effects in California forests are reviewed. Climatic characteristics of California are summarized in light of their effects on pollutant accumulation and transport. Over large areas of the state dry deposition is of greater magnitude than wet deposition due to the arid climate. However, fog deposition can also be significant in areas where seasonal fogs and N pollution sources coincide. The dominance of dry deposition is magnified in airsheds with frequent temperature inversions such as occur in the Los Angeles Air Basin. Most of the deposition in such areas occurs in summer as a result of surface deposition of nitric acid vapor (HNO3) as well as particulate nitrate (NO3-) and ammonium (NH4+). Internal uptake of gaseous N pollutants such as nitrogen dioxide (NO2), nitric oxide (NO), HNO3, peroxyacetyl nitrate (PAN), ammonia (NH3), and others provides additional N to forests. However, summer drought and subsequent lower stomatal conductance of plants tend to limit plant utilization of gaseous N. Nitrogen deposition is much greater than S deposition in California. In locations close to photochemical smog source areas, concentrations of oxidized forms of N (NO2, HNO3, PAN) dominate, while in areas near agricultural activities the importance of reduced N forms (NH3, NH4+) significantly increases. Little data from California forests are available for most of the gaseous N pollutants. Total inorganic N deposition in the most highly-exposed forests in the Los Angeles Air Basin may be as high as 25-45 kg ha(-1) year(-1). Nitrogen deposition in these highly-exposed areas has led to N saturation of chaparral and mixed conifer stands. In N saturated forests high concentrations of NO3- are found in streamwater, soil solution, and in foliage. Nitric oxide emissions from soil and foliar N:P ratios are also high in N saturated sites. Further research is needed to determine the

  5. Convective drying of sludge cake

    Science.gov (United States)

    Chen, Jianbo; Peng, Xiaofeng; Xue, Yuan; Lee, Duujong; Chu, Chingping

    2002-08-01

    This paper presented an experimental study on convective drying of waste water sludge collected from Beijing GaoBeiDian Sewage Treatment Plant, particularly on the correlation between the observed shrinkage dynamics of sludge cake and the drying curve. During the initial stage of drying the process resembles to that of a particulate bed, in which moisture diffuses and evaporates at the upper surface. Conventional drying theory assuming a diffusion-evaporating front interprets this period of drying. Consequently, owing to the very large shrinkage ratio of the dried cake, cracks emerges and propagates on and within the cake body, whence inducing evaporating channel that facilitates the water removal. This occurrence compensates the reduction of surface area for evaporation, whence extending the constant-rate period during the test. Afterwards, the cracks meet with each other and form isolated cake piles, while the subsequent drying occur mainly within these piles and the conventional theory fails. The transition between the drying on a plain cake layer and that on the isolated piles demonstrates the need to adopt distinct descriptions on these two regimes of drying for the sludge cake.

  6. Dust deposits on Mars: The 'parna' analog

    Science.gov (United States)

    Greeley, Ronald; Williams, Steven H.

    1994-07-01

    Parna is an Australian aboriginal word meaning 'sandy dust'. It has been applied to deposits of clay, silt, and sand which were initially transported by the wind as aggregates, or pellets, of sand size. Parna is distinguished by its silt and clay content, which in some cases exceeds 85% of the total volume of the deposit. Much of the fine-grained playa silt and clay is incorporated into the parna as sand-sized aggregates, which greatly facilitate their transportation and reworking by the wind. Rain following aggregate emplacement can cause their disintegration, rendering the parna immobile by the wind, yet some pellets can survive several wetting/drying episodes. Parna deposits on Earth occur both as dune forms and as sheet deposits which mantle older terrains. In both cases the deposits are typically derived from lacustrine (lake) beds, such as playas. There is substantial evidence to suggest that bodies of water existed on Mars in the past. Thus, the potential is high for lacustrine deposits and the formation of parna on Mars. Although no parna dunes have been identified, it is suggested that the deposits derived from White Rock (-8 deg, 335 deg W), near Mamers Valles (34 deg, 343 deg W), and elsewhere on Mars may represent sheet parna. Data obtained from Mars-94/96 missions and potential landed spacecraft may provide additional evidence for the existence of parna on Mars.

  7. Drying Spirulina with Foam Mat Drying at Medium Temperature

    Directory of Open Access Journals (Sweden)

    Aji Prasetyaningrum

    2012-10-01

    Full Text Available Spirulina is a single cell blue green microalgae (Cyanobacteria containing many Phytonutrients (Beta-carotene, Chlorophyl, Xanthophyl, Phyocianin using as anti-carcinogen in food. Producing dry spirulina by quick drying process at medium temperature is very important to retain the Phytonutrient quality. Currently, the work is still challenging due to the gel formation that block the water diffusion from inside to the surface.  This research studies the performance of foam-mat drying on production of dry spirulina. In this method the spirulina was mixed with foaming agent (glair/egg albumen, popular as white egg at 2.5% by weight at air velocity 2.2 m/sec. Here, the effect of spirulina thickness and operational temperature on drying time and quality (Beta-carotene and color were observed. The drying time was estimated based on the measurement of water content in spirulina versus time. Result showed that the thicker spirulina, the longer drying time. Conversely, the higher operational temperature, faster drying time. At thickness ranging 1-3 mm and operational temperature below 70oC, the quality of spirulina can fit the market requirement

  8. Carrageenan drying with dehumidified air: drying characteristics and product quality

    NARCIS (Netherlands)

    Djaeni, M.; Sasongko, S.B.; Prasetyaningrum, Aji A A.A.; Jin, X.; Boxtel, van A.J.B.

    2012-01-01

    Applying dehumidified air is considered as an option to retain quality in carrageenan drying. This work concerns the effects of operational temperature, air velocity, and carrageenan thickness on the progress of drying and product quality when using dehumidified air. Final product quality and progre

  9. Staying dry under water

    Science.gov (United States)

    Jones, Paul; Cruz-Chu, Eduardo; Megaridis, Constantine; Walther, Jens; Koumoutsakos, Petros; Patankar, Neelesh

    2012-11-01

    Lotus leaves are known for their non-wetting properties due to the presence of surface texture. The superhydrophobic behavior arises because of the prevention of liquid water from entering the pores of the roughness. Present superhydrophobic materials rely on air trapped within the surface pores to avoid liquid permeation. This is typically unsustainable for immersed bodies due to dissolution of the air, especially under elevated pressures. Here, molecular dynamics simulations are used to demonstrate the non-wetting behavior of an immersed ten-nanometer pore. This is accomplished by establishing thermodynamically sustained vapor pockets of the surrounding liquid medium. Over 300,000 atoms were used to construct the nanopore geometry and simulate SPC/E water molecules. Ambient pressure was varied along two isotherms (300 K, and 500 K). This approach for vapor-stabilization could offer valuable guidance for maintaining surfaces dry even in a submerged state without relying on trapped air. The approach may be extended to control general phase behavior of water adjacent to textured surfaces. ISEN support is gratefully acknowledged.

  10. Forward Osmosis Brine Drying

    Science.gov (United States)

    Flynn, Michael; Shaw, Hali; Hyde, Deirdre; Beeler, David; Parodi, Jurek

    2015-01-01

    The Forward Osmosis Brine Drying (FOBD) system is based on a technique called forward osmosis (FO). FO is a membrane-based process where the osmotic potential between brine and a salt solution is equalized by the movement of water from the brine to the salt solution. The FOBD system is composed of two main elements, the FO bag and the salt regeneration system. This paper discusses the results of testing of the FO bag to determine the maximum water recovery ratio that can be attained using this technology. Testing demonstrated that the FO bag is capable of achieving a maximum brine water recovery ratio of the brine of 95%. The equivalent system mass was calculated to be 95 kg for a feed similar to the concentrated brine generated on the International Space Station and 86 kg for an Exploration brine. The results have indicated that the FOBD can process all the brine for a one year mission for between 11% to 10% mass required to bring the water needed to make up for water lost in the brine if not recycled. The FOBD saves 685 kg and when treating the International Space Station brine and it saves 829 kg when treating the Exploration brine. It was also demonstrated that saturated salt solutions achieve a higher water recovery ratios than solids salts do and that lithium chloride achieved a higher water recovery ratio than sodium chloride.

  11. Viscous property of dried clay

    Institute of Scientific and Technical Information of China (English)

    XU Li-sheng; LI Jian-zhong

    2006-01-01

    One dimensional and triaxial compression tests of air-dried and oven-dried Fujinomori clay and Pisa clay were carried out. Water content is less than 4.5 % and 1.0% for air-dried and oven-dried clay specimens, respectively. In all tests, axial strain rate was changed stepwise many times and drained creep tests were performed several times during monotonic loading at a constant strain rate. Global unloading (and also reloading in some tests) was applied during which creep loading tests were performed several times. Cyclic loading with small stress amplitude and several cycles was also performed to calculate the modulus of elasticity of the clay in tests. Local displacement transducer was used in triaxial compression test to increase measuring accuracy of axial strain. The results show that air-dried and oven-dried clay have noticeable viscous properties; during global unloading, creep deformation changes from positive to negative, i.e. there exist neutral points (zero creep deformation or no creep deformation point) in global unloading part of strain-stress curve; viscous property of Fujinomori clay decreases when water content decreases, i.e. viscous property of air-dried Fujinomori clay is more significant than that of oven-dried Fujinomori clay.

  12. Microwave Drying of Moist Coals

    Science.gov (United States)

    Salomatov, Vl. V.; Karelin, V. A.; Sladkov, S. O.; Salomatov, Vas. V.

    2017-03-01

    Physical principles and examples of practical implementation of drying large bodies of coal by microwave radiation are considered. It is shown that energy consumption in microwave drying of brown coals decreases to 1.5-1.8 (kW·h)/ kg as compared with traditional types of drying, for which the expenditures of energy amount to 3.0 (kW·h)/kg. In using microwave drying, the technological time of drying decreases to 4 h, whereas the time of convective drying, with other things being equal, comes to 8-20 h. Parallel with microwave radiation drying, grinding of a fuel takes place, as well as entrainment of such toxic and ecologically harmful elements as mercury, chlorine, phosphorus, sulfur, and nitrogen. An analysis of the prospects of using a microwave energy for drying coal fuel has shown that microwave radiation makes it possible to considerably economize in energy, increase explosional safety, improve the ecological situation, and reduce the metal content and overall dimensions of the equipment.

  13. Atmospheric Deposition of Copper and Zinc in Maramures County (Romania

    Directory of Open Access Journals (Sweden)

    Buteana Claudia

    2014-12-01

    Full Text Available The need to reduce pollution to levels that minimize adverse effects on human health involve the monitoring of air quality, including dry depositions and their metal content. The analysis of these parameters aims to investigate the air quality in Maramures County (with nonferrous mining activities and in the Romanian - Ukraine transboundary area. The paper presents the experimental results obtained for dry atmospheric deposition of copper and zinc using flame atomic absorption spectrometry (FAAS. The samples were collected from four location/cities of Maramures County (Baia Mare, Sighetu Marmatiei, Viseu de Sus and Borsa during May-October 2014. The highest average values of copper concentration in the dry depositions were found in Baia Mare (199.88 μg/g, that is the most important industrial centre in Maramures County, followed by Borsa (111.49 μg/g, that used to be a nonferrous mining centre. In Viseu de Sus and Sighetu Marmatiei the average concentrations of copper in the dry depositions were lower: 75.63 μg/g and 64.26 μg/g, respectively. Zn average concentrations in dry depositions were 6.4-12 times higher than Cu concentrations. In Viseu de Sus and Borsa relative high values of Pearson correlation coefficients between the logarithm of Cu and Zn content in the dry deposition were found (0.702 and 0.737, respectively estimating that both pollutants in the ambient air have the same sources, probably the re-suspension of the dust from the tailing ponds. This study is implemented within the frame of ENPI Cross-border Cooperation Programme Hungary-Slovakia-Romania-Ukraine 2007-2013, in the project Clean Air Management in the Romania-Ukraine Transboundary Area - (CLAMROUA, financed by the European Union

  14. Factors Controlling Black Carbon Deposition in Snow in the Arctic

    Science.gov (United States)

    Qi, L.; Li, Q.; He, C.; Li, Y.

    2015-12-01

    This study evaluates the sensitivity of black carbon (BC) concentration in snow in the Arctic to BC emissions, dry deposition and wet scavenging efficiency using a 3D global chemical transport model GEOS-Chem driven by meteorological field GEOS-5. With all improvements, simulated median BC concentration in snow agrees with observation (19.2 ng g-1) within 10%, down from -40% in the default GEOS-Chem. When the previously missed gas flaring emissions (mainly located in Russia) are included, the total BC emission in the Arctic increases by 70%. The simulated BC in snow increases by 1-7 ng g-1, with the largest improvement in Russia. The discrepancy of median BC in snow in the whole Arctic reduces from -40% to -20%. In addition, recent measurements of BC dry deposition velocity suggest that the constant deposition velocity of 0.03 cm s-1 over snow and ice used in the GEOS-Chem is too low. So we apply resistance-in-series method to calculate the dry deposition velocity over snow and ice and the resulted dry deposition velocity ranges from 0.03 to 0.24 cm s-1. However, the simulated total BC deposition flux in the Arctic and BC in snow does not change, because the increased dry deposition flux has been compensated by decreased wet deposition flux. However, the fraction of dry deposition to total deposition increases from 16% to 25%. This may affect the mixing of BC and snow particles and further affect the radative forcing of BC deposited in snow. Finally, we reduced the scavenging efficiency of BC in mixed-phase clouds to account for the effect of Wegener-Bergeron-Findeisen (WBF) process based on recent observations. The simulated BC concentration in snow increases by 10-100%, with the largest increase in Greenland (100%), Tromsø (50%), Alaska (40%), and Canadian Arctic (30%). Annual BC loading in the Arctic increases from 0.25 to 0.43 mg m-2 and the lifetime of BC increases from 9.2 to 16.3 days. This indicates that BC simulation in the Arctic is really sensitive to

  15. Switchable Adhesion in Vacuum Using Bio-Inspired Dry Adhesives

    OpenAIRE

    Purtov, Julia; Frensemeier, Mareike; Kroner, Elmar

    2015-01-01

    Suction based attachment systems for pick and place handling of fragile objects like glass plates or optical lenses are energy-consuming and noisy and fail at reduced air pressure, which is essential, e.g., in chemical and physical vapor deposition processes. Recently, an alternative approach toward reversible adhesion of sensitive objects based on bioinspired dry adhesive structures has emerged. There, the switching in adhesion is achieved by a reversible buckling of adhesive pillar structur...

  16. Drying Characteristics of Garcinia atroviridis

    Directory of Open Access Journals (Sweden)

    Waigoon RITTIRUT

    2006-01-01

    Full Text Available Some physical and chemical properties of fresh garcinia fruits are reported. The most suitable drying conditions for garcinia material in a tray dryer based on the final moisture content were determined by extensive testing. It was found that for the material thickness of 2, 4 and 6 mm, a temperature of 55 °C and air velocity of 1.2 m/s are suitable for drying. The most suitable time where the final moisture content met the commercial standard was found to be 199, 256 and 427 min, respectively. The higher the temperature, the shorter the drying time. It was also observed that the suitable drying time for 2-mm thick material and air velocity of 1.2 m/s was 199, 159 and 99 min for drying temperature of 55, 65 and 75 °C, respectively. Drying characteristics are also reported. Most of the drying rate curves appear in a falling rate period except at low temperature and low velocity of operation parameters i.e. 55 °C and 0.5 m/s for 4-mm thick material, where the constant drying rate is approximately 0.09 kg water/min.m2. The sorption isotherm is sigmoidal shape at 30 °C and monolayer moisture content is 14.78 kg water/100 kg dry solid. Soaking material in 1.5 and 3.0 %w/w sodium chloride did not affect the drying rate. Effective moisture diffusivities were evaluated to be  5.57´10-10, 6.94´10-10 and 1.11´10-9 m2/s at temperatures 55, 65 and 75 °C, respectively.

  17. Space and Industrial Brine Drying Technologies

    Science.gov (United States)

    Jones, Harry W.; Wisniewski, Richard S.; Flynn, Michael; Shaw, Hali

    2014-01-01

    This survey describes brine drying technologies that have been developed for use in space and industry. NASA has long considered developing a brine drying system for the International Space Station (ISS). Possible processes include conduction drying in many forms, spray drying, distillation, freezing and freeze drying, membrane filtration, and electrical processes. Commercial processes use similar technologies. Some proposed space systems combine several approaches. The current most promising candidates for use on the ISS use either conduction drying with membrane filtration or spray drying.

  18. Drying of α-amylase by spray drying and freeze-drying - a comparative study

    Directory of Open Access Journals (Sweden)

    S. S. de Jesus

    2014-09-01

    Full Text Available This study is aimed at comparing two traditional methods of drying of enzymes and at verifying the efficiency of each one and their advantages and disadvantages. The experiments were performed with a laboratory spray dryer and freeze-dryer using α-amylase as the model enzyme. An experimental design in star revealed that spray drying is mainly influenced by the inlet air temperature and feed flow rate, which were considered to be the main factors influencing the enzymatic activity and water activity; the long period of material exposure to high temperatures causes a partial activity loss. In the experiments of freeze drying, three methods of freezing were used (freezer, acetone and dry ice, and liquid nitrogen and samples subsequently freeze-dried for times ranging between 0-24 hours. The product obtained from the two techniques showed high enzymatic activity and low water activity. For the drying of heat-resistant enzymes, in which the product to be obtained does not have high added value, spray drying may be more economically viable because, in the freeze drying process, the process time can be considered as a limiting factor when choosing a technique.

  19. Homogeneous deposition of particles on hydrogels by absorption

    Science.gov (United States)

    Boulogne, François; Ingremeau, François; Dervaux, Julien; Limat, Laurent; Stone, Howard

    2016-11-01

    A drying drop containing solid particles, such as coffee, leaves a ring stain resulting from the accumulation of the particles near a contact line. In many industrial applications such as printing, coating or biological microtechnologies, these inhomogeneities must be avoided. To suppress the coffee stain effect, different strategies have been developed.In the present work, we propose to substitute the drying by absorption in hydrogels to extract the solvent of a colloidal drop. We study the deposition mechanisms of micrometer-sized particles on the surface of swelling hydrogels. To the best of our knowledge, we show for the first time that the particle deposition on these gels is homogeneous. Using fluorescence microscopy coupled with particle tracking techniques, we record the flow field inside the droplet and analyze the particle deposition mechanism. We rationalize our findings with a theoretical model for the absorption and the particle deposition dynamics that enables the measurement of the diffusion coefficient in the gels.

  20. Drying of thin colloidal films

    Science.gov (United States)

    Routh, Alexander F.

    2013-04-01

    When thin films of colloidal fluids are dried, a range of transitions are observed and the final film profile is found to depend on the processes that occur during the drying step. This article describes the drying process, initially concentrating on the various transitions. Particles are seen to initially consolidate at the edge of a drying droplet, the so-called coffee-ring effect. Flow is seen to be from the centre of the drop towards the edge and a front of close-packed particles passes horizontally across the film. Just behind the particle front the now solid film often displays cracks and finally the film is observed to de-wet. These various transitions are explained, with particular reference to the capillary pressure which forms in the solidified region of the film. The reasons for cracking in thin films is explored as well as various methods to minimize its effect. Methods to obtain stratified coatings through a single application are considered for a one-dimensional drying problem and this is then extended to two-dimensional films. Different evaporative models are described, including the physical reason for enhanced evaporation at the edge of droplets. The various scenarios when evaporation is found to be uniform across a drying film are then explained. Finally different experimental techniques for examining the drying step are mentioned and the article ends with suggested areas that warrant further study.

  1. No Heat Spray Drying Technology

    Energy Technology Data Exchange (ETDEWEB)

    Beetz, Charles [ZoomEssence, Inc., Hebron, KY (United States)

    2016-06-15

    No Heat Spray Drying Technology. ZoomEssence has developed our Zooming™ spray drying technology that atomizes liquids to powders at ambient temperature. The process of drying a liquid into a powder form has been traditionally achieved by mixing a heated gas with an atomized (sprayed) fluid within a vessel (drying chamber) causing the solvent to evaporate. The predominant spray drying process in use today employs air heated up to 400° Fahrenheit to dry an atomized liquid into a powder. Exposing sensitive, volatile liquid ingredients to high temperature causes molecular degradation that negatively impacts solubility, stability and profile of the powder. In short, heat is detrimental to many liquid ingredients. The completed award focused on several areas in order to advance the prototype dryer to a commercial scale integrated pilot system. Prior to the award, ZoomEssence had developed a prototype ‘no-heat’ dryer that firmly established the feasibility of the Zooming™ process. The award focused on three primary areas to improve the technology: (1) improved ability to formulate emulsions for specific flavor groups and improved understanding of the relationship of emulsion properties to final dry particle properties, (2) a new production atomizer, and (3) a dryer controls system.

  2. Cascadia Tsunami Deposit Database

    Science.gov (United States)

    Peters, Robert; Jaffe, Bruce; Gelfenbaum, Guy; Peterson, Curt

    2003-01-01

    The Cascadia Tsunami Deposit Database contains data on the location and sedimentological properties of tsunami deposits found along the Cascadia margin. Data have been compiled from 52 studies, documenting 59 sites from northern California to Vancouver Island, British Columbia that contain known or potential tsunami deposits. Bibliographical references are provided for all sites included in the database. Cascadia tsunami deposits are usually seen as anomalous sand layers in coastal marsh or lake sediments. The studies cited in the database use numerous criteria based on sedimentary characteristics to distinguish tsunami deposits from sand layers deposited by other processes, such as river flooding and storm surges. Several studies cited in the database contain evidence for more than one tsunami at a site. Data categories include age, thickness, layering, grainsize, and other sedimentological characteristics of Cascadia tsunami deposits. The database documents the variability observed in tsunami deposits found along the Cascadia margin.

  3. Cassava Sun Drying Performance on Various Surfaces and Drying ...

    African Journals Online (AJOL)

    a raw material in the production of starch, tapioca and snack foods ... The material was dried for 8 hours daily after which it was kept indoors overnight. The surface with .... statistical package (MS Office, 2007). .... preservation and marketing.

  4. EFFECT OF DRYING CONDITIONS ON MUSHROOM QUALITY

    Directory of Open Access Journals (Sweden)

    MANOJ KULSHRESHTHA

    2009-03-01

    Full Text Available Fluidized bed drying of mushroom was undertaken to study the drying characteristics and quality of the dried mushrooms. Drying was done at drying air temperatures of 50, 70, and 90oC and air velocities of 1.71 and 2.13 m/s. Two batch sizes, namely, 0.5 kg and 1 kg of sliced milky mushrooms were dried. Drying characteristics and the quality of dried mushrooms were analyzed. The results indicated that the drying time decreased only marginally with increase in air velocity. Drying air temperature of 50oC was better as it resulted in a dried product having better rehydration characteristics, lesser shrinkage and lighter color. Highest energy efficiency (79.74% was observed while drying a batch size of 1 kg at a drying air temperature of 50oC, using an air velocity of 1.7 m/s.

  5. Picoliter solution deposition for total reflection X-ray fluorescence analysis of semiconductor samples

    Energy Technology Data Exchange (ETDEWEB)

    Sparks, Chris M., E-mail: chris.sparks@svtc.co [Analytical Services, SVTC Technologies, Austin, TX 78741 (United States); Fittschen, Ursula E.A. [Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Institute of Inorganic and Applied Chemistry, University of Hamburg, 20146 Hamburg (Germany); Havrilla, George J. [Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2010-09-15

    A deposition system capable of delivering picoliter quantities of solution in programmable arrays was investigated as a method for sample preparation for total reflection X-ray fluorescence (TXRF) spectroscopy. Arrays of trace metals in solution were deposited on Si wafers. The array deposits provide a capability of depositing closely spaced (100 {mu}m or less), typically 5-20 {mu}m diameter droplets in an area that can be matched to the analysis spot of the TXRF detector. The dried depositions were physically characterized and the effect of deposition type and matrix on the TXRF signal was investigated.

  6. Natural wind drying of willow stems

    NARCIS (Netherlands)

    Gigler, J.K.; Loon, van W.K.P.; Berg, van den J.V.; Sonneveld, C.; Meerdink, G.

    2000-01-01

    The process of natural wind drying of willow (Salix viminalis) stems in large piles was investigated. A simple drying model was developed for stems. Large-scale drying experiments were conducted and drying data were statistically analysed. Whether drying in a pile of willow stems was uniform was inv

  7. A Mathematical Model for Freeze-Drying

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Based on the experiments on freeze-drying carrot and potato slabs, the effects of some parameters, such as heating temperature and pressure on the freeze-drying process are examined. A simple model of freeze-drying is established to predict drying time and the mass variations of materials during the drying. The experimental results agree well with those calculated by the model.

  8. Dry powder platform for pulmonary drug delivery

    Institute of Scientific and Technical Information of China (English)

    Derek Ivan Daniher; Jesse Zhu

    2008-01-01

    The phenomenon of particle interaction involved in pulmonary drug delivery belongs to a wide variety of disciplines of particle technology, in particular, fluidization. This paper reviews the basic concepts of pulmonary drug delivery with references to fluidization research, in particular, studies on Geldart group C powders. Dry powder inhaler device-formulation combination has been shown to be an effective method for delivering drugs to the lung for treatment of asthma, chronic obstructive pulmonary disease and cystic fibrosis. Even with advanced designs, however, delivery efficiency is still poor mainly due to powder dispersion problems which cause poor lung deposition and high dose variability. Drug particles used in current inhalers must be 1-5 μm in diameter for effective deposition in small-diameter airways and alveoli. These powders are very cohesive, have poor flowability, and are difficult to disperse into aerosol due to cohesion arising from van tier Waals attraction. These problems are well known in fluidization research, much of which is highly relevant to pulmonary drug delivery.

  9. 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...

  10. 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...

  11. 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...

  12. Thermal energy in dry snow avalanches

    Science.gov (United States)

    Steinkogler, W.; Sovilla, B.; Lehning, M.

    2015-09-01

    Avalanches can exhibit many different flow regimes from powder clouds to slush flows. Flow regimes are largely controlled by the properties of the snow released and entrained along the path. Recent investigations showed the temperature of the moving snow to be one of the most important factors controlling the mobility of the flow. The temperature of an avalanche is determined by the temperature of the released and entrained snow but also increases by frictional processes with time. For three artificially released avalanches, we conducted snow profiles along the avalanche track and in the deposition area, which allowed quantifying the temperature of the eroded snow layers. This data set allowed to calculate the thermal balance, from release to deposition, and to discuss the magnitudes of different sources of thermal energy of the avalanches. For the investigated dry avalanches, the thermal energy increase due to friction was mainly depending on the effective elevation drop of the mass of the avalanche with a warming of approximately 0.3 °C per 100 vertical metres. Contrarily, the temperature change due to entrainment varied for the individual avalanches, from -0.08 to 0.3 °C, and depended on the temperature of the snow along the path and the erosion depth. Infrared radiation thermography (IRT) was used to assess the surface temperature before, during and just after the avalanche with high spatial resolution. This data set allowed to identify the warmest temperatures to be located in the deposits of the dense core. Future research directions, especially for the application of IRT, in the field of thermal investigations in avalanche dynamics are discussed.

  13. Thermal energy in dry snow avalanches

    Directory of Open Access Journals (Sweden)

    W. Steinkogler

    2014-11-01

    Full Text Available Avalanches can exhibit many different flow regimes from powder clouds to slush flows. Flow regimes are largely controlled by the properties of the snow released and entrained along the path. Recent investigations showed the temperature of the moving snow to be one of the most important factors controlling the mobility of the flow. The temperature of an avalanche is determined by the temperature of the released and entrained snow but also increases by frictional and collisional processes with time. For three artificially released avalanches, we conducted snow profiles along the avalanche track and in the deposition area, which allowed quantifying the temperature of the eroded snow layers. Infrared radiation thermography (IRT was used to assess the surface temperature before, during and just after the avalanche with high spatial resolution. This data set allowed to calculate the thermal balance, from release to deposition, and to discuss the magnitudes of different sources of thermal energy of the avalanches. We could confirm that, for the investigated dry avalanches, the thermal energy increase due to friction was mainly depending on the elevation drop of the avalanche with a warming of approximately 0.5 °C per 100 height meters. Contrary, warming due to entrainment was very specific to the individual avalanche and depended on the temperature of the snow along the path and the erosion depth ranging from nearly no warming to a maximum observed warming of 1 °C. Furthermore, we could observe the warmest temperatures are located in the deposits of the dense core. Future research directions, especially for the application of IRT, in the field of thermal investigations in avalanche dynamics are discussed.

  14. Sustaining dry surfaces under water

    DEFF Research Database (Denmark)

    Jones, Paul R.; Hao, Xiuqing; Cruz-Chu, Eduardo R.

    2015-01-01

    Rough surfaces immersed under water remain practically dry if the liquid-solid contact is on roughness peaks, while the roughness valleys are filled with gas. Mechanisms that prevent water from invading the valleys are well studied. However, to remain practically dry under water, additional...... mechanisms need consideration. This is because trapped gas (e.g. air) in the roughness valleys can dissolve into the water pool, leading to invasion. Additionally, water vapor can also occupy the roughness valleys of immersed surfaces. If water vapor condenses, that too leads to invasion. These effects have...... not been investigated, and are critically important to maintain surfaces dry under water.In this work, we identify the critical roughness scale, below which it is possible to sustain the vapor phase of water and/or trapped gases in roughness valleys – thus keeping the immersed surface dry. Theoretical...

  15. 10-minute consultation Dry mouth

    Institute of Scientific and Technical Information of China (English)

    Mark Taubert; Eleanor M R Davies; Ian Back

    2007-01-01

    @@ A 67 year old man presents with a six week history of dry mouth (xerostomia). He has prostate cancer, which has spread to his spine, and he takes opiates for pain relief. Recently, he started taking an antidepressant.

  16. Sustaining dry surfaces under water

    Science.gov (United States)

    Jones, Paul R.; Hao, Xiuqing; Cruz-Chu, Eduardo R.; Rykaczewski, Konrad; Nandy, Krishanu; Schutzius, Thomas M.; Varanasi, Kripa K.; Megaridis, Constantine M.; Walther, Jens H.; Koumoutsakos, Petros; Espinosa, Horacio D.; Patankar, Neelesh A.

    2015-08-01

    Rough surfaces immersed under water remain practically dry if the liquid-solid contact is on roughness peaks, while the roughness valleys are filled with gas. Mechanisms that prevent water from invading the valleys are well studied. However, to remain practically dry under water, additional mechanisms need consideration. This is because trapped gas (e.g. air) in the roughness valleys can dissolve into the water pool, leading to invasion. Additionally, water vapor can also occupy the roughness valleys of immersed surfaces. If water vapor condenses, that too leads to invasion. These effects have not been investigated, and are critically important to maintain surfaces dry under water. In this work, we identify the critical roughness scale, below which it is possible to sustain the vapor phase of water and/or trapped gases in roughness valleys - thus keeping the immersed surface dry. Theoretical predictions are consistent with molecular dynamics simulations and experiments.

  17. Dry skin - self-care

    Science.gov (United States)

    ... moisture Hot, dry air in desert environments Air conditioners that cool the air and remove moisture Taking ... scrubbing your skin. Shave right after bathing, when hair is soft. Wear soft, comfortable clothing next to ...

  18. 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

  19. Biomimetic thin film deposition

    Science.gov (United States)

    Rieke, P. C.; Campbell, A. A.; Tarasevich, B. J.; Fryxell, G. E.; Bentjen, S. B.

    1991-04-01

    Surfaces derivatized with organic functional groups were used to promote the deposition of thin films of inorganic minerals. These derivatized surfaces were designed to mimic the nucleation proteins that control mineral deposition during formation of bone, shell, and other hard tissues in living organisms. By the use of derivatized substrates control was obtained over the phase of mineral deposited, the orientation of the crystal lattice and the location of deposition. These features are of considerable importance in many technically important thin films, coatings, and composite materials. Methods of derivatizing surfaces are considered and examples of controlled mineral deposition are presented.

  20. Dry aging of beef; Review

    OpenAIRE

    Dashdorj, Dashmaa; Tripathi, Vinay Kumar; Cho, Soohyun; Kim, Younghoon; Hwang, Inho

    2016-01-01

    The present review has mainly focused on the specific parameters including aging (aging days, temperature, relative humidity, and air flow), eating quality (flavor, tenderness and juiciness), microbiological quality and economic (shrinkage, retail yields and cost) involved beef dry aging process. Dry aging is the process where beef carcasses or primal cuts are hanged and aged for 28 to 55 d under controlling environment conditions in a refrigerated room with 0° to 4 °C and with relative humid...

  1. Dry PMR-15 Resin Powders

    Science.gov (United States)

    Vannucci, Raymond D.; Roberts, Gary D.

    1988-01-01

    Shelf lives of PMR-15 polymides lengthened. Procedure involves quenching of monomer reactions by vacuum drying of PRM-15 resin solutions at 70 to 90 degree F immediately after preparation of solutions. Absence of solvent eliminates formation of higher esters and reduces formation of imides to negligible level. Provides fully-formulated dry PMR-15 resin powder readily dissolvable in solvent at room temperature immediately before use. Resins used in variety of aerospace, aeronautical, and commercial applications.

  2. Whole wafer critical point drying of MEMS devices

    Science.gov (United States)

    Resnick, Paul J.; Clews, Peggy J.

    2001-10-01

    Stiction induced by capillary forces during the post-release drying step of MEMS fabrication can substantially limit the functional yield of complex devices. Supercritical CO2 drying provides a method to remove liquid from the device surface without creating a liquid/vapor interface, thereby mitigating stiction. We show that a continuous stirred-tank reactor (CSTR) model can be applied as a method to estimate the volume of liquid CO2 required to effectively displace the post release solvent. The CSTR model predicts that about 8 volume exchanges is sufficient to effectively displace the methanol to a concentration below the saturation point. Experimental data indicate that about 10 exchanges are adequate for repeatable drying of complex devices, which is in reasonable agreement to the model prediction. In addition to drying devices without inducing stiction, the process must be inherently non-contaminating. Data indicate that the majority of contaminants deposited during the drying process can be attributed to contaminants originating in the post-release solvent, rather than the supercritical CO2 process.

  3. Advantages on dry interim storage for spent nuclear fuel

    Energy Technology Data Exchange (ETDEWEB)

    Romanato, L.S. [Centro Tecnologico da Marinha em Sao Paulo, Av. Professor Lineu Prestes 2468, 05508-900 Sao Paulo (Brazil); Rzyski, B.M. [IPEN/ CNEN-SP, 05508-000 Sao Paulo (Brazil)]. e-mail: romanato@ctmsp.mar.mil.br

    2006-07-01

    When the nuclear fuel lose its ability to efficiently create energy it is removed from the core reactor and moved to a storage unit waiting for a final destination. Generally, the spent nuclear fuel (SNF) remains inside concrete basins with water within the reactors facility for the radioactive activity decay. Water cools the generated heat and shields radioactivity emissions. After some period of time in water basins the SNF can be sent to a definitive deposition in a geological repository and handled as radioactive waste or to reprocessing installations, or still wait for a future solution. Meanwhile, SNF remains stored for a period of time in dry or wet installations, depending on the method adopted by the nuclear power plant or other plans of the country. In many SNF wet storage sites the capacity can be fulfilled very quickly. If so, additional area or other alternative storage system should be given. There are many options to provide capacity increase in the wet storage area, but dry storages are worldwide preferred since it reduces corrosion concerns. In the wet storage the temperature and water purity should be constantly controlled whereas in the dry storage the SNF stands protected in specially designed canisters. Dry interim storages are practical and approved in many countries especially that have the 'wait and see' philosophy (wait to see new technologies development). This paper shows the advantages of dry interim storages sites in comparison with the wet ones and the nowadays problems as terrorism. (Author)

  4. 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.

  5. Dry adhesives with sensing features

    Science.gov (United States)

    Krahn, J.; Menon, C.

    2013-08-01

    Geckos are capable of detecting detachment of their feet. Inspired by this basic observation, a novel functional dry adhesive is proposed, which can be used to measure the instantaneous forces and torques acting on an adhesive pad. Such a novel sensing dry adhesive could potentially be used by climbing robots to quickly realize and respond appropriately to catastrophic detachment conditions. The proposed torque and force sensing dry adhesive was fabricated by mixing Carbon Black (CB) and Polydimethylsiloxane (PDMS) to form a functionalized adhesive with mushroom caps. The addition of CB to PDMS resulted in conductive PDMS which, when under compression, tension or torque, resulted in a change in the resistance across the adhesive patch terminals. The proposed design of the functionalized dry adhesive enables distinguishing an applied torque from a compressive force in a single adhesive pad. A model based on beam theory was used to predict the change in resistance across the terminals as either a torque or compressive force was applied to the adhesive patch. Under a compressive force, the sensing dry adhesive was capable of measuring compression stresses from 0.11 Pa to 20.9 kPa. The torque measured by the adhesive patch ranged from 2.6 to 10 mN m, at which point the dry adhesives became detached. The adhesive strength was 1.75 kPa under an applied preload of 1.65 kPa for an adhesive patch with an adhesive contact area of 7.07 cm2.

  6. Morphology of drying blood pools

    Science.gov (United States)

    Laan, Nick; Smith, Fiona; Nicloux, Celine; Brutin, David; D-Blood project Collaboration

    2016-11-01

    Often blood pools are found on crime scenes providing information concerning the events and sequence of events that took place on the scene. However, there is a lack of knowledge concerning the drying dynamics of blood pools. This study focuses on the drying process of blood pools to determine what relevant information can be obtained for the forensic application. We recorded the drying process of blood pools with a camera and measured the weight. We found that the drying process can be separated into five different: coagulation, gelation, rim desiccation, centre desiccation, and final desiccation. Moreover, we found that the weight of the blood pool diminishes similarly and in a reproducible way for blood pools created in various conditions. In addition, we verify that the size of the blood pools is directly related to its volume and the wettability of the surface. Our study clearly shows that blood pools dry in a reproducible fashion. This preliminary work highlights the difficult task that represents blood pool analysis in forensic investigations, and how internal and external parameters influence its dynamics. We conclude that understanding the drying process dynamics would be advancement in timeline reconstitution of events. ANR funded project: D-Blood Project.

  7. Dry Eyes and Glaucoma: Double Trouble

    Science.gov (United States)

    ... News About Us Donate In This Section Dry Eyes and Glaucoma: Double Trouble email Send this article ... disease bothers the patient more. What Causes Dry Eye Syndrome? Dry eye can be caused by many ...

  8. Bauxite Deposits in China

    Institute of Scientific and Technical Information of China (English)

    杨化洲

    1989-01-01

    Bauxite deposits in China,rangin in age from Late Paleozoic to Cenozoic ,are distributed mainly in Shanxi,Shandong Henan,Guizhou,Guangxi and Yunnan.Based on stratigraphic relations they can be clas-sified as 6 types:inter-system marine,inter-system continental,intra-system marine,intra-system continent-tal,weathering lateritic and weathering accumulation types.But in terms of depositional environments,only four types are distinguished,I.e.the marine deposits,continental deposits,lateritic deposits and weath-ering-accumulation deposits.These deposits have been formed in two steps:firstly,the depression of paraplatform or front basin margins in paleocontinents and secondly,the development of littoral-lagoons on the eroded surface of karstified carbonate bedrocks.The aluminum may have been derived from the carbonate rocks with which the ores are associated,or from adjacent aluminosilicate rocks.

  9. 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

  10. Recent advances in liposomal dry powder formulations: preparation and evaluation.

    Science.gov (United States)

    Misra, Ambikanandan; Jinturkar, Kaustubh; Patel, Deepa; Lalani, Jigar; Chougule, Mahavir

    2009-01-01

    Liposomal drug dry powder formulations have shown many promising features for pulmonary drug administration, such as selective localization of drug within the lung, controlled drug release, reduced local and systemic toxicities, propellant-free nature, patient compliance, high dose carrying capacity, stability and patent protection. Critical review of the recent developments will provide a balanced view on benefits of liposomal encapsulation while developing dry powder formulations and will help researchers to update themselves and focus their research in more relevant areas. In liposomal dry powder formulations (LDPF), drug encapsulated liposomes are homogenized, dispersed into the carrier and converted into dry powder form by using freeze drying, spray drying and spray freeze drying. Alternatively, LDPF can also be formulated by supercritical fluid technologies. On inhalation with a suitable inhalation device, drug encapsulated liposomes get rehydrated in the lung and release the drug over a period of time. The prepared LDPF are evaluated in vitro and in vivo for lung deposition behavior and drug disposition in the lung using a suitable inhaler device. The most commonly used liposomes are composed of lung surfactants and synthetic lipids. Delivery of anticancer agents for lung cancer, corticosteroids for asthma, immunosuppressants for avoiding lung transplantation rejection, antifungal drugs for lung fungal infections, antibiotics for local pulmonary infections and cystic fibrosis and opioid analgesics for pain management using liposome technology are a few examples. Many liposomal formulations have reached the stage of clinical trials for the treatment of pulmonary distress, cystic fibrosis, lung fungal infection and lung cancer. These formulations have given very promising results in both in vitro and in vivo studies. However, modifications to new therapies for respiratory diseases and systemic delivery will provide new challenges in conducting well

  11. High-intensity drying processes-impulse drying

    Energy Technology Data Exchange (ETDEWEB)

    Orloff, D.I.

    1991-06-01

    Impulse drying is an innovative process for drying paper that holds great promise for reducing the energy consumed during the manufacture of paper and similar web products. impulse drying occurs when a wet paper web passes through a press nip in which one of the rolls is heated to a high temperature. A steam layer adjacent to the heated surface grows and displaces water from the sheet in a very efficient manner. The energy required for water removal is very much less than that required for conventional evaporative drying. To eliminate sheet delamination, low thermal mass ceramic press roll coatings were developed to reduce heat transfer to the sheet, while maintaining high heat flux during early stages of the process. In so doing, most of the transferred energy is used to form steam that displaces liquid water, rather than in excessively heating the sheet. During this period, a prototype ceramic coating was developed and its impulse drying performance was compared to that of steel surfaces. It was observed that ceramic platens can be operated at higher temperatures and pressures resulting in improved water removal and physical properties without inducing sheet delamination. Heat flux measurement techniques were developed to provide a mechanistic explanation for the superior performance of the prototype. The work confirmed that the prototype ceramic coating is more energy efficient than the steel surface.

  12. High-intensity drying processes-impulse drying. Yearly report

    Energy Technology Data Exchange (ETDEWEB)

    Orloff, D.I.

    1991-06-01

    Impulse drying is an innovative process for drying paper that holds great promise for reducing the energy consumed during the manufacture of paper and similar web products. impulse drying occurs when a wet paper web passes through a press nip in which one of the rolls is heated to a high temperature. A steam layer adjacent to the heated surface grows and displaces water from the sheet in a very efficient manner. The energy required for water removal is very much less than that required for conventional evaporative drying. To eliminate sheet delamination, low thermal mass ceramic press roll coatings were developed to reduce heat transfer to the sheet, while maintaining high heat flux during early stages of the process. In so doing, most of the transferred energy is used to form steam that displaces liquid water, rather than in excessively heating the sheet. During this period, a prototype ceramic coating was developed and its impulse drying performance was compared to that of steel surfaces. It was observed that ceramic platens can be operated at higher temperatures and pressures resulting in improved water removal and physical properties without inducing sheet delamination. Heat flux measurement techniques were developed to provide a mechanistic explanation for the superior performance of the prototype. The work confirmed that the prototype ceramic coating is more energy efficient than the steel surface.

  13. The use of a large-strain consolidation model to optimise multilift tailing deposits

    NARCIS (Netherlands)

    Vardon, P.J.; Yao, Y.; Van Paassen, L.A.; Van Tol, A.F.

    2015-01-01

    Thin-lift atmospheric fine drying (AFD) is a technique used to dewater mine and oil sand tailings, which utilises both self-weight consolidation and atmospheric evaporation. The disposed layers undergo a cyclic drying and rewetting process due to precipitation and deposition of additional lifts on

  14. Rapid deposition of oxidized biogenic compounds to a temperate forest

    Science.gov (United States)

    Nguyen, Tran B.; Crounse, John D.; Teng, Alex P.; St. Clair, Jason M.; Paulot, Fabien; Wolfe, Glenn M.; Wennberg, Paul O.

    2015-02-01

    We report fluxes and dry deposition velocities for 16 atmospheric compounds above a southeastern United States forest, including: hydrogen peroxide (H2O2), nitric acid (HNO3), hydrogen cyanide (HCN), hydroxymethyl hydroperoxide, peroxyacetic acid, organic hydroxy nitrates, and other multifunctional species derived from the oxidation of isoprene and monoterpenes. The data suggest that dry deposition is the dominant daytime sink for small, saturated oxygenates. Greater than 6 wt %C emitted as isoprene by the forest was returned by dry deposition of its oxidized products. Peroxides account for a large fraction of the oxidant flux, possibly eclipsing ozone in more pristine regions. The measured organic nitrates comprise a sizable portion (15%) of the oxidized nitrogen input into the canopy, with HNO3 making up the balance. We observe that water-soluble compounds (e.g., strong acids and hydroperoxides) deposit with low surface resistance whereas compounds with moderate solubility (e.g., organic nitrates and hydroxycarbonyls) or poor solubility (e.g., HCN) exhibited reduced uptake at the surface of plants. To first order, the relative deposition velocities of water-soluble compounds are constrained by their molecular diffusivity. From resistance modeling, we infer a substantial emission flux of formic acid at the canopy level (∼1 nmol m-2ṡs-1). GEOS-Chem, a widely used atmospheric chemical transport model, currently underestimates dry deposition for most molecules studied in this work. Reconciling GEOS-Chem deposition velocities with observations resulted in up to a 45% decrease in the simulated surface concentration of trace gases.

  15. Rapid Deposition of Oxidized Biogenic Compounds to a Temperate Forest

    Science.gov (United States)

    Nguyen, Tran B.; Crounse, John D.; Teng, Alex P.; St. Clair, Jason M.; Paulot, Fabien; Wolfe, Glenn M.; Wennberg, Paul O.

    2015-01-01

    We report fluxes and dry deposition velocities for 16 atmospheric compounds above a southeastern United States forest, including: hydrogen peroxide (H2O2), nitric acid (HNO3), hydrogen cyanide (HCN), hydroxymethyl hydroperoxide, peroxyacetic acid, organic hydroxy nitrates, and other multifunctional species derived from the oxidation of isoprene and monoterpenes. The data suggest that dry deposition is the dominant daytime sink for small, saturated oxygenates. Greater than 6 wt %C emitted as isoprene by the forest was returned by dry deposition of its oxidized products. Peroxides account for a large fraction of the oxidant flux, possibly eclipsing ozone in more pristine regions. The measured organic nitrates comprise a sizable portion (15%) of the oxidized nitrogen input into the canopy, with HNO3 making up the balance. We observe that water-soluble compounds (e.g., strong acids and hydroperoxides) deposit with low surface resistance whereas compounds with moderate solubility (e.g., organic nitrates and hydroxycarbonyls) or poor solubility (e.g., HCN) exhibited reduced uptake at the surface of plants. To first order, the relative deposition velocities of water-soluble compounds are constrained by their molecular diffusivity. From resistance modeling, we infer a substantial emission flux of formic acid at the canopy level (approx. 1 nmol m(exp.-2)·s(exp.-1)). GEOS-Chem, awidely used atmospheric chemical transport model, currently underestimates dry deposition for most molecules studied in this work. Reconciling GEOS-Chem deposition velocities with observations resulted in up to a 45% decrease in the simulated surface concentration of trace gases.

  16. Gas storage in "dry water" and "dry gel" clathrates.

    Science.gov (United States)

    Carter, Benjamin O; Wang, Weixing; Adams, Dave J; Cooper, Andrew I

    2010-03-02

    "Dry water" (DW) is a free-flowing powder prepared by mixing water, hydrophobic silica particles, and air at high speeds. We demonstrated recently that DW can be used to dramatically enhance methane uptake rates in methane gas hydrate (MGH). Here, we expand on our initial work, demonstrating that DW can be used to increase the kinetics of formation of gas clathrates for gases other than methane, such as CO(2) and Kr. We also show that the stability of the system toward coalescence can be increased via the inclusion of a gelling agent to form a "dry gel", thus dramatically improving the recyclability of the material. For example, the addition of gellan gum allows effective reuse over at least eight clathration cycles without the need for reblending. DW and its "dry gel" modification may represent a potential platform for recyclable gas storage or gas separation on a practicable time scale in a static, unmixed system.

  17. PREBIOTICS AS DRYING AIDS FOR SPRAY DRYING FRUIT JUICES

    Directory of Open Access Journals (Sweden)

    R. FREIXO

    2016-10-01

    Full Text Available Natural fruit juices are difficult to transform into powder because they are rich in sugars and acids with low glass transition temperatures, resulting in a sticky behaviour during spray drying. The present research work aimed to test the prebiotics maltodextrin and arabic gum as drying agents in order to be able to produce dehydrated powder from pineapple, strawberry and apple juices. 2 % of maltodextrin and an inlet air temperature of 130 °C are recommended to spray dry apple juice, reaching 60 % yield of powder with a water activity below 0.40. For strawberry juice, 2 % of this carrier is recommended and the inlet air temperature, 120 °C or 130 °C, did not seem relevant. For pineapple, neither the concentration of the carrier nor the inlet air temperature seemed to be relevant.

  18. Deposition of carbonyl sulphide to soils

    Science.gov (United States)

    Kluczewski, S. M.; Brown, K. A.; Bel, J. N. B.

    Carbonyl sulphide (COS) is a trace constituent of the atmosphere and is also the main form in which 35S is released from CO 2-cooled nuclear reactors. Measurements of its deposition velocity ( Vg) are therefore important for validating radiological dose models and for interpreting the role of COS in the global S cycle. The Vg of [ 35S]COS to thin layers of several contrasting soils was measured in a through-flow fumigation system. Deposition velocity was not significantly affected by soil type, although deposition to moist soil was significantly greater ( P dried soils, mean values being 5.71 × 10 -6 ms -1 and 3.06 × 10 -6 ms -1, respectively. The results obtained are about three orders of magnitude smaller than published Vg values for SO 2 to similar soils, which suggests that uptake by soils is not a major sink for atmospheric COS. The results are consistent with the hypothesis that deposition to soil of [ 35S]COS from nuclear reactors is unlikely to contribute significantly to radiation dose from the food chain pathway. The reduction in Vg observed in heat-treated soils indicates a microbial involvement in uptake. However, it seems unlikely that microbial metabolism is the rate-controlling step, since stimulation of the microflora by the addition of nutrients did not increase COS deposition.

  19. Impact of gaseous nitrogen deposition on plant functioning

    NARCIS (Netherlands)

    Stulen, I.; Perez-Soba, M; De Kok, LJ; Van der Eerden, L

    1998-01-01

    Dry deposition of NH3 and NOx (NO and NO2) can affect plant metabolism at the cellular and whole-plant level. Gaseous pollutants enter the plant mainly through the stomata, and once in the apoplast NH3 dissolves to form NH4+, whereas NO2 dissolves to form NO3- and NO2-. The latter compound can also

  20. Potential evapotranspiration and continental drying

    Science.gov (United States)

    Milly, P. C. D.; Dunne, K. A.

    2016-10-01

    By various measures (drought area and intensity, climatic aridity index, and climatic water deficits), some observational analyses have suggested that much of the Earth’s land has been drying during recent decades, but such drying seems inconsistent with observations of dryland greening and decreasing pan evaporation. `Offline’ analyses of climate-model outputs from anthropogenic climate change (ACC) experiments portend continuation of putative drying through the twenty-first century, despite an expected increase in global land precipitation. A ubiquitous increase in estimates of potential evapotranspiration (PET), driven by atmospheric warming, underlies the drying trends, but may be a methodological artefact. Here we show that the PET estimator commonly used (the Penman-Monteith PET for either an open-water surface or a reference crop) severely overpredicts the changes in non-water-stressed evapotranspiration computed in the climate models themselves in ACC experiments. This overprediction is partially due to neglect of stomatal conductance reductions commonly induced by increasing atmospheric CO2 concentrations in climate models. Our findings imply that historical and future tendencies towards continental drying, as characterized by offline-computed runoff, as well as other PET-dependent metrics, may be considerably weaker and less extensive than previously thought.

  1. Bioaerosol deposition on an air-conditioning cooling coil

    Science.gov (United States)

    Wu, Yan; Chen, Ailu; Luhung, Irvan; Gall, Elliott T.; Cao, Qingliang; Chang, Victor Wei-Chung; Nazaroff, William W.

    2016-11-01

    This study is concerned with the role of a fin-and-tube heat exchanger in modifying microbial indoor air quality. Specifically, depositional losses of ambient bioaerosols and particles onto dry (not cooled) and wet (cool) coil surfaces were measured for different airspeeds passing through the test coil. Total, bacterial and fungal DNA concentrations in condensate water produced by a wet coil were also quantified by means of fluorescent dsDNA-binding dye and qPCR assays. Results revealed that the deposition of bioaerosols and total particles is substantial on coil surfaces, especially when wet and cool. The average deposition fraction was 0.14 for total DNA, 0.18 for bacterial DNA and 0.22 for fungal DNA on the dry coil, increasing to 0.51 for total DNA, 0.50 for bacterial DNA and 0.68 for fungal DNA on the wet coil. Overall, as expected, deposition fractions increased with increasing particle size and increasing airspeed. Deposited DNA was removed from the cooling coil surfaces through the flow of condensing water at a rate comparable to the rate of direct deposition from air. A downward trend of bacterial and fungal DNA measured in condensate water over time provides suggestive evidence of biological growth on heat exchangers during nonoperational times of a ventilation system. This investigation provides new information about bioaerosol deposition onto a conventional fin-and-tube cooling coil, a potentially important factor influencing indoor exposure to microbial aerosols in air-conditioned buildings.

  2. 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...

  3. ElectroSpark Deposition

    Science.gov (United States)

    2007-01-25

    ElectroSpark Deposition Hard Chrome Alternatives Team Joint Cadmium Alternatives Team Canadian Hard Chrome Alternatives Team Joint Group on Pollution...00-2007 to 00-00-2007 4. TITLE AND SUBTITLE ElectroSpark Deposition 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S...Processes, Inc. ElectroSpark Deposition (ESD) Results of Materials Testing and Technology Insertion January 25, 2007 Advanced Surfaces And Processes, Inc. 3

  4. Doping suppression and mobility enhancement of graphene transistors fabricated using an adhesion promoting dry transfer process

    Energy Technology Data Exchange (ETDEWEB)

    Cheol Shin, Woo; Hun Mun, Jeong; Yong Kim, Taek; Choi, Sung-Yool; Jin Cho, Byung, E-mail: bjcho@kaist.edu, E-mail: tskim1@kaist.ac.kr [Department of Electrical Engineering, Graphene Research Center, KAIST, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Yoon, Taeshik; Kim, Taek-Soo, E-mail: bjcho@kaist.edu, E-mail: tskim1@kaist.ac.kr [Department of Mechanical Engineering, Graphene Research Center, KAIST, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

    2013-12-09

    We present the facile dry transfer of graphene synthesized via chemical vapor deposition on copper film to a functional device substrate. High quality uniform dry transfer of graphene to oxidized silicon substrate was achieved by exploiting the beneficial features of a poly(4-vinylphenol) adhesive layer involving a strong adhesion energy to graphene and negligible influence on the electronic and structural properties of graphene. The graphene field effect transistors (FETs) fabricated using the dry transfer process exhibit excellent electrical performance in terms of high FET mobility and low intrinsic doping level, which proves the feasibility of our approach in graphene-based nanoelectronics.

  5. Doping suppression and mobility enhancement of graphene transistors fabricated using an adhesion promoting dry transfer process

    Science.gov (United States)

    Cheol Shin, Woo; Yoon, Taeshik; Hun Mun, Jeong; Yong Kim, Taek; Choi, Sung-Yool; Kim, Taek-Soo; Jin Cho, Byung

    2013-12-01

    We present the facile dry transfer of graphene synthesized via chemical vapor deposition on copper film to a functional device substrate. High quality uniform dry transfer of graphene to oxidized silicon substrate was achieved by exploiting the beneficial features of a poly(4-vinylphenol) adhesive layer involving a strong adhesion energy to graphene and negligible influence on the electronic and structural properties of graphene. The graphene field effect transistors (FETs) fabricated using the dry transfer process exhibit excellent electrical performance in terms of high FET mobility and low intrinsic doping level, which proves the feasibility of our approach in graphene-based nanoelectronics.

  6. Aerosol Deposition and Solar Panel Performance

    Science.gov (United States)

    Arnott, W. P.; Rollings, A.; Taylor, S. J.; Parks, J.; Barnard, J.; Holmes, H.

    2015-12-01

    Passive and active solar collector farms are often located in relatively dry desert regions where cloudiness impacts are minimized. These farms may be susceptible to reduced performance due to routine or episodic aerosol deposition on collector surfaces. Intense episodes of wind blown dust deposition may negatively impact farm performance, and trigger need to clean collector surfaces. Aerosol deposition rate depends on size, morphology, and local meteorological conditions. We have developed a system for solar panel performance testing under real world conditions. Two identical 0.74 square meter solar panels are deployed, with one kept clean while the other receives various doses of aerosol deposition or other treatments. A variable load is used with automation to record solar panel maximum output power every 10 minutes. A collocated sonic anemometer measures wind at 10 Hz, allowing for both steady and turbulent characterization to establish a link between wind patterns and particle distribution on the cells. Multispectral photoacoustic instruments measure aerosol light scattering and absorption. An MFRSR quantifies incoming solar radiation. Solar panel albedo is measured along with the transmission spectra of particles collected on the panel surface. Key questions are: At what concentration does aerosol deposition become a problem for solar panel performance? What are the meteorological conditions that most strongly favor aerosol deposition, and are these predictable from current models? Is it feasible to use the outflow from an unmanned aerial vehicle hovering over solar panels to adequately clean their surface? Does aerosol deposition from episodes of nearby forest fires impact performance? The outlook of this research is to build a model that describes environmental effects on solar panel performance. Measurements from summer and fall 2015 will be presented along with insights gleaned from them.

  7. Saharan dust transport and deposition towards the Tropical Northern Atlantic

    Directory of Open Access Journals (Sweden)

    K. Schepanski

    2008-08-01

    Full Text Available We present a study of Saharan dust export towards the tropical North Atlantic using the regional dust emission, transport and deposition model LM-MUSCAT. Horizontal and vertical distribution of dust optical thickness, concentration, and dry and wet deposition rates are used to describe seasonality of dust export and deposition towards the eastern Atlantic for three exemplary months in different seasons. Deposition rates strongly depend on the vertical dust distribution, which differs with seasons. Furthermore the contribution of dust originating from the Bodélé Depression to Saharan dust over the Atlantic is investigated. A maximum contribution of Bodélé dust transported towards the Cape Verde Islands is evident in winter when the Bodélé source area is most active and dominant with regard activation frequency and dust emission. Limitations of using satellite retrievals to estimate dust deposition are highlighted.

  8. Linking enhanced deposition agent functionality with aesthetic performance.

    Science.gov (United States)

    Erazo-Majewicz, Paquita; Roberts-Howard, Cathleen; Oldham, Eugene; Lynch, Craig; Graham, John; Usher, Courtney R; Joneja, Surendra

    2011-01-01

    This study examines the cationic polymers 1) guar hydroxypropyltrimonium chloride polymers (GHPTC), 2) acrylamidopropyltrimonium chloride/acrylamide copolymer (APTAC/Acm), 3) polyquaternium polymers (PQ-10, PQ-7, PQ-67), and 4) a new polymer system approach for their a) deposition efficiency (as measured by quantifying oils deposited on virgin hair) and b) ability to deliver good wet and dry lubricity to the hair from a cleansing formulation as measured by comb energy and friction characteristics of the hair samples. Conditioning polymer technology approaches 1) acrylamidopropyltrimonium chloride/acrylamide copolymer, 2) a guar hydroxypropyltrimonium chloride polymer, and 3) the new polymer system approach deliver superior deposition of natural conditioning oils and dimethicone materials from anionic/amphoteric surfactant cleansing formulations. These new polymer technologies offer formulators the ability to improve uniformity of deposition as well as deposition efficiency of conditioning agents onto hair, and target the desired hair lubricity.

  9. 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.

  10. Nitrogen deposition effects on Mediterranean-type ecosystems: An ecological assessment

    Science.gov (United States)

    R. Ochoa-Hueso; E.B. Allen; C. Branquinho; C. Cruz; T. Dias; Mark Fenn; E. Manrique; M.E. Pérez-Corona; L.J. Sheppard; W.D. Stock

    2011-01-01

    We review the ecological consequences of N deposition on the five Mediterranean regions of the world. Seasonality of precipitation and fires regulate the N cycle in these water-limited ecosystems, where dry N deposition dominates. Nitrogen accumulation in soils and on plant surfaces results in peaks of availability with the first winter rains. Decoupling between N...

  11. Drying characteristics and kinetics of fluidized bed dried potato

    Directory of Open Access Journals (Sweden)

    S.B. BAKAL

    2008-12-01

    Full Text Available In developed countries, more than 50% potatoes are consumed as processed products. As drying is the vital phenomenon in processing, it is necessary to investigate the drying characteristics and its kinetics. In this experimental study, drying kinetics of Potato in two different shape of cuboidal & cylindrical with three aspect ratio was investigated as a function of drying conditions. Experiments were conducted using air temperatures of 50, 60 and 70 ºC, at velocity of 7 ms-1. The experimental moisture data were fitted to Page and simple models available in the literature, and a good agreement was observed. The Page model gave better fit than simple model. In the ranges covered, the values of the effective moisture diffusivity, Deff were obtained between 2.278 × 10-9 to 3.314 × 10-8 m2s-1 from the Fick's diffusion model. Using Deff, the value of activation energy (Ea was determined assuming the Arrhenius-type temperature relationship.

  12. Solar Drying of Red Mud

    Science.gov (United States)

    Chandler, John L.

    Solar drying of thickened red mud is the latest method for its disposal in an economical and environmentally acceptable way. Two years full scale experience with this method in Jamaica has shown that its success depends on accurate grading of the solar drying area and accurate control of the pre-dewatering of the mud in the alumina plant. Experience with the use of deep thickening for pre-dewatering is described, together with a novel method for measurement and control of thickened mud rheology.

  13. Development of freeze dried vegetables

    Science.gov (United States)

    Larson, R. W.

    1970-01-01

    The development of freeze dried vegetables to be used in the Apollo food system is discussed. After the initial selection and screening of vegetables, several types of freeze dried vegetables were prepared in small batches. From these small batches, two vegetables were judged satisfactory for further testing and evaluation. These vegetables, mashed potatoes and asparagus, were subjected to storage at 100 deg plus or minus 5 F. for two weeks and then taste tested. The vegetables were also tested to determine if they complied with the microbiological requirements for Apollo food. The space food prototype production guide for the vegetables is submitted.

  14. Dry technologies and community bureaucracies

    DEFF Research Database (Denmark)

    Rasmussen, Mattias Borg

    2014-01-01

    Irrigation channels criss-cross the Andes, bringing water to the dry soils of the peasants' fields. To obtain water, people must deal not only with the amount of water and the physical terrain, but also with concerns of others and matters of the social terrain.......Irrigation channels criss-cross the Andes, bringing water to the dry soils of the peasants' fields. To obtain water, people must deal not only with the amount of water and the physical terrain, but also with concerns of others and matters of the social terrain....

  15. Fundamentals of freeze-drying.

    Science.gov (United States)

    Nail, Steven L; Jiang, Shan; Chongprasert, Suchart; Knopp, Shawn A

    2002-01-01

    Given the increasing importance of reducing development time for new pharmaceutical products, formulation and process development scientists must continually look for ways to "work smarter, not harder." Within the product development arena, this means reducing the amount of trial and error empiricism in arriving at a formulation and identification of processing conditions which will result in a quality final dosage form. Characterization of the freezing behavior of the intended formulation is necessary for developing processing conditions which will result in the shortest drying time while maintaining all critical quality attributes of the freeze-dried product. Analysis of frozen systems was discussed in detail, particularly with respect to the glass transition as the physical event underlying collapse during freeze-drying, eutectic mixture formation, and crystallization events upon warming of frozen systems. Experiments to determine how freezing and freeze-drying behavior is affected by changes in the composition of the formulation are often useful in establishing the "robustness" of a formulation. It is not uncommon for seemingly subtle changes in composition of the formulation, such as a change in formulation pH, buffer salt, drug concentration, or an additional excipient, to result in striking differences in freezing and freeze-drying behavior. With regard to selecting a formulation, it is wise to keep the formulation as simple as possible. If a buffer is needed, a minimum concentration should be used. The same principle applies to added salts: If used at all, the concentration should be kept to a minimum. For many proteins a combination of an amorphous excipient, such as a disaccharide, and a crystallizing excipient, such as glycine, will result in a suitable combination of chemical stability and physical stability of the freeze-dried solid. Concepts of heat and mass transfer are valuable in rational design of processing conditions. Heat transfer by conduction

  16. 7 CFR 58.813 - Dry whey.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Dry whey. 58.813 Section 58.813 Agriculture... Products Bearing Usda Official Identification § 58.813 Dry whey. The quality requirements for dry whey shall be in accordance with the U.S. Standards for Dry Whey. Supplemental Specifications for...

  17. Dry Sintered Metal Coating of Halloysite Nanotubes

    Directory of Open Access Journals (Sweden)

    James C. Nicholson

    2016-09-01

    Full Text Available Halloysite nanotubes (HNTs are a naturally-occurring aluminosilicate whose dimensions measure microns in length and tens of nanometers in diameter. Bonding defects between the alumina and silica lead to net negative and positive charges on the exterior and interior lumen, respectively. HNTs have been shown to enhance the material properties of polymer matrices and enable the sustained release of loaded chemicals, drugs, and growth factors. Due to the net charges, these nanotubes can also be readily coated in layered-depositions using the HNT exterior lumen’s net negative charge as the basis for assembly. These coatings are primarily done through wet chemical processes, the majority of which are limited in their use of desired chemicals, due to the polarity of the halloysite. Furthermore, this restriction in the type of chemicals used often requires the use of more toxic chemicals in place of greener options, and typically necessitates the use of a significantly longer chemical process to achieve the desired coating. In this study, we show that HNTs can be coated with metal acetylacetonates—compounds primarily employed in the synthesis of nanoparticles, as metal catalysts, and as NMR shift reagents—through a dry sintering process. This method was capable of thermally decaying the metal acetylacetonate, resulting in a free positively-charged metal ion that readily bonded to the negatively-charged HNT exterior, resulting in metallic coatings forming on the HNT surface. Our coating method may enable greater deposition of coated material onto these nanotubes as required for a desired application. Furthermore, the use of chemical processes using toxic chemicals is not required, thus eliminating exposure to toxic chemicals and costs associated with the disposal of the resultant chemical waste.

  18. MAPLE deposition of nanomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Caricato, A.P., E-mail: annapaola.caricato@le.infn.it [Department of Mathematics and Physics “E. De Giorgi”, University of Salento, Via Arnesano, I-73100 Lecce (Italy); Arima, V.; Catalano, M. [National Nanotechnology Laboratory (NNL), CNR Istituto Nanoscienze, c/o Distretto Tecnologico, Via Arnesano n. 16, I-73100 Lecce (Italy); Cesaria, M. [Department of Mathematics and Physics “E. De Giorgi”, University of Salento, Via Arnesano, I-73100 Lecce (Italy); Cozzoli, P.D. [Department of Mathematics and Physics “E. De Giorgi”, University of Salento, Via Arnesano, I-73100 Lecce (Italy); National Nanotechnology Laboratory (NNL), CNR Istituto Nanoscienze, c/o Distretto Tecnologico, Via Arnesano n. 16, I-73100 Lecce (Italy); Martino, M. [Department of Mathematics and Physics “E. De Giorgi”, University of Salento, Via Arnesano, I-73100 Lecce (Italy); Taurino, A.; Rella, R. [Institute for Microelectronics and Microsystems, IMM-CNR, Via Monteroni, I-73100 Lecce (Italy); Scarfiello, R. [National Nanotechnology Laboratory (NNL), CNR Istituto Nanoscienze, c/o Distretto Tecnologico, Via Arnesano n. 16, I-73100 Lecce (Italy); Tunno, T. [Department of Mathematics and Physics “E. De Giorgi”, University of Salento, Via Arnesano, I-73100 Lecce (Italy); Zacheo, A. [Department of Mathematics and Physics “E. De Giorgi”, University of Salento, Via Arnesano, I-73100 Lecce (Italy); National Nanotechnology Laboratory (NNL), CNR Istituto Nanoscienze, c/o Distretto Tecnologico, Via Arnesano n. 16, I-73100 Lecce (Italy)

    2014-05-01

    The matrix-assisted pulsed laser evaporation (MAPLE) has been recently exploited for depositing films of nanomaterials by combining the advantages of colloidal inorganic nanoparticles and laser-based techniques. MAPLE-deposition of nanomaterials meeting applicative purposes demands their peculiar properties to be taken into account while planning depositions to guarantee a congruent transfer (in terms of crystal structure and geometric features) and explain the deposition outcome. In particular, since nanofluids can enhance thermal conductivity with respect to conventional fluids, laser-induced heating can induce different ablation thermal regimes as compared to the MAPLE-treatment of soft materials. Moreover, nanoparticles exhibit lower melting temperatures and can experience pre-melting phenomena as compared to their bulk counterparts, which could easily induce shape and or crystal phase modification of the material to be deposited even at very low fluences. In this complex scenario, this review paper focuses on examples of MAPLE-depositions of size and shape controlled nanoparticles for different applications highlights advantages and challenges of the MAPLE-technique. The influence of the deposition parameters on the physical mechanisms which govern the deposition process is discussed.

  19. Hybrid Rice for Dry Regions

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Luo Lijun, director of the Shanghai Agrobiological Gene Center, recently announced that Hanyou No. 3 - a genetically modified rice capable of producing high yields in dry areas - has been developed at the center.The hybrid yields 7,571 kilograms per hectare, about the same as ordinary rice.

  20. Apparatus for drying sugar cubes

    NARCIS (Netherlands)

    Derckx, H.A.J.; Torringa, H.M.

    1999-01-01

    Device for drying sugar cubes containing a heating apparatus for heating and dehumidifying the sugar cubes, a conditioning apparatus for cooling off and possibly further dehumidifying the sugar cubes and a conveying apparatus for conveying the sugar cubes through the heating apparatus and the condit

  1. Apparatus for drying sugar cubes

    NARCIS (Netherlands)

    Derckx, H.A.J.; Torringa, H.M.

    1999-01-01

    Device for drying sugar cubes containing a heating apparatus for heating and dehumidifying the sugar cubes, a conditioning apparatus for cooling off and possibly further dehumidifying the sugar cubes and a conveying apparatus for conveying the sugar cubes through the heating apparatus and the

  2. Longevity Of Dry Film Lubricants

    Science.gov (United States)

    Kannel, J. W.; Stockwell, R. D.

    1993-01-01

    Report describes evaluation of dry film lubricants candidate for use in rotary joints of proposed Space Station. Study included experiments and theoretical analyses focused on longevity of sputtered molybdenum disulfide films and ion-plated lead films under conditions partially simulating rolling contact.

  3. Apparatus for drying sugar cubes

    NARCIS (Netherlands)

    Derckx, H.A.J.; Torringa, H.M.

    1999-01-01

    Device for drying sugar cubes containing a heating apparatus for heating and dehumidifying the sugar cubes, a conditioning apparatus for cooling off and possibly further dehumidifying the sugar cubes and a conveying apparatus for conveying the sugar cubes through the heating apparatus and the condit

  4. Flavour release from dried vegetables.

    NARCIS (Netherlands)

    Ruth, van S.M.

    1995-01-01

    The research described in this thesis was focused on the development of an in vitro model system for isolation of volatile compounds from dried vegetables under mouth conditions, such as volume of the mouth, temperature, salivation and mastication. Instrumental analysis of these volatile compoun

  5. Solid on liquid deposition

    Energy Technology Data Exchange (ETDEWEB)

    Charmet, J., E-mail: jerome.charmet@he-arc.c [Institut des Microtechnologies Appliquees ARC, HES-SO Arc, Eplatures-Grise 17, 2300 La Chaux-de-Fonds (Switzerland); Banakh, O.; Laux, E.; Graf, B.; Dias, F.; Dunand, A.; Keppner, H. [Institut des Microtechnologies Appliquees ARC, HES-SO Arc, Eplatures-Grise 17, 2300 La Chaux-de-Fonds (Switzerland); Gorodyska, G.; Textor, M. [BioInterface group, ETHZ, Wolfgang-Pauli-Strasse 10, ETH Hoenggerberg HCI H 525 8093 Zuerich (Switzerland); Noell, W.; Rooij, N.F. de [Ecole Polytechnique Federale de Lausanne, Institute of Microengineering, Sensors, Actuators and Microsystems laboratory, Rue Jaquet Droz 1, 2000 Neuchatel (Switzerland); Neels, A.; Dadras, M.; Dommann, A.; Knapp, H. [Centre Suisse d' Electronique et de Microtechnique SA, Rue Jacquet-Droz 1, 2002 Neuchatel (Switzerland); Borter, Ch.; Benkhaira, M. [COMELEC SA, Rue de la Paix 129, 2300 La Chaux-de-Fonds (Switzerland)

    2010-07-01

    A process for the deposition of a solid layer onto a liquid is presented. The polymer poly-di-chloro-para-xylylene, also known as Parylene C, was grown on low vapour pressure liquids using the conventional low pressure chemical vapour deposition process. A reactor was built and a process developed to enable the deposition of Parylene C at atmospheric pressure over high vapour pressure liquids. It was used to deposit Parylene C over water among others. In all cases Parylene C encapsulated the liquid without influencing its initial shape. The results presented here show also that the Parylene C properties are not affected by its growth on liquid templates and the roughness of the Parylene C surface in contact with the liquid during the deposition is extremely low.

  6. 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.

  7. Determination of drying characteristics and quality properties of eggplant in different drying conditions

    Directory of Open Access Journals (Sweden)

    Gözde Bayraktaroglu Urun

    2015-12-01

    Full Text Available Drying is the most traditional process used for preserving eggplant a long time. The aim of this study was to determining drying characteristics and quality properties of eggplant dried by sun drying, hot air convective drying and infrared assisted convective drying. Convective drying and infrared assisted convective were carried out in a convective dryer at three different temperatures(40°, 50°, 60°C and air velocity at 5 m/s.The increasing of temperatures during the drying of eggplant led to a significant reduction of the drying time. However loss of nutrition was observed in eggplant samples dried at higher temperature.The biggest change in colour parameters was observed in samples dried with sun drying.So it was thought that sun drying had a negative effect on quality properties of eggplant samples.

  8. Tsunami Deposit Data Base

    Science.gov (United States)

    Keating, B. H.; Wanink, M.

    2007-05-01

    A digital database has been established describing tsunami deposits around the world (3 phases; 15 months). The projects involved the review and tabulation of data derived from books, catalogs, journals, preprints, citations and abstracts (currently 1000 references), into a database designed to provide a comprehensive review of the types of tsunami deposits, their geographic distribution and location, sedimentary characteristics, fossil content, age, preservation, run-up, wave height and inundation observations, etc. (34 parameters). The tsunami occurrences can be divided into many subjects, e.g., Volcanogenic (N=375), Seismites (N=49), Co-seismic (N=258), K/T Boundary Impact-triggered debris flows (N=97), Landslides (N=43), etc. Numerous publications compare tsunami deposits to storm deposits (N=38), or analyze the origin of megaboulders (N=22). Tsunami deposits occur throughout geologic time (Pre-Cambrian to present day), and because of plate tectonics, they occur along plate margins (primarily subduction zones) as well as interior to plates. In addition, they occur in epi-continental seas, fjords, etc. Few publications describe depositional processes. Deposits generated by tsunamis occur in multiple environments such as the marine, fresh water, and subaerial. Common characteristics of tsunami deposits include: 1) Deposition of thin sand sheets (can be normal, massive, inversely graded, chaotic or bimodal). 2) Erosional: basal uncomformity, mud balls, rip-up clasts, reworked fossils produced by scouring. 3) Lithology: Stacks of couplets reflecting marine incursions (often sands) into fresh water or subaerial environments (mud, soil, peat). 4) Fossil: Couplets reflects marine fossils, fresh water fossils or a mixed assemblage. 5) Geomorphology: The sand sheets taper landward and can rise in elevation. 6) Deformation: syn-depositional (soft sediments) and intraformational (stiff sediments).

  9. 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.

  10. Deposition of radionuclides and stable elements in Tokai-mura

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, Takashi; Amano, Hikaru [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    This report presents the data of deposition of radionuclides (Sep. 1993-March 2001) and stable elements (Sep. 1993-Oct. 1995) in Tokai-mura. To evaluate the migration of radionuclides and stable elements from the atmosphere to the ground surface, atmospheric deposition samples were collected from Sep. 1993 to March 2001 with three basins (distance to grand surface were 1.5 m, 4 m, 10 m) set up in the enclosure of JAERI in Tokai-mura, Ibaraki-ken, Japan. Monthly samples were evaporated to dryness to obtain residual samples and measured with a well type Ge detector for {sup 7}Be, {sup 40}K, {sup 137}Cs and {sup 210}Pb. According to the analysis of radioactivity, clear seasonal variations with spring peaks of deposition weight (dry) and deposition amounts of all objective radionuclides were found. Correlation analysis of deposition data also showed that these radionuclides can be divided into two groups. A part of dried sample was irradiated to reactor neutrons at JRR-4 for determination of stable element's deposition. (author)

  11. e‑MALDI: An Electrowetting-Enhanced Drop Drying Method for

    NARCIS (Netherlands)

    Kudina, O.; Eral, H.B.; Mugele, F.

    2016-01-01

    The performance of matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) is frequently compromised by the heterogeneous distribution of matrix and analyte deposits on the target plate arising during the conventional drop-drying sample preparation procedure. It was recently shown t

  12. e‑MALDI: An Electrowetting-Enhanced Drop Drying Method for MALDI Mass Spectrometry

    NARCIS (Netherlands)

    Kudina, Olena; Eral, Burak; Mugele, Frieder

    2016-01-01

    The performance of matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) is frequently compromised by the heterogeneous distribution of matrix and analyte deposits on the target plate arising during the conventional drop-drying sample preparation procedure. It was recently shown t

  13. Design and evaluation of a new dry powder inhaler

    Directory of Open Access Journals (Sweden)

    "Rouholamini Najafabadi AH

    2001-08-01

    Full Text Available Three versions of a new dry powder inhaler (DPI, RG-haler, were designed using two kinds of grid inserts. Salbutamol sulfate/lactose blend (Ventolin Rotacaps® was selected as a model formulation to analyze the performance of all inhalers and compare their efficiency with three marketed devices (Rotahaler®, Spinhaler® and ISF inhalator® using the twin impinger (TI. Deposition of the drug in device was significantly (P<0.05 lower for ISF inhalator® and all kinds of RG-halers in comparison with those of Rotahaler® and Spinhaler®. The amount of drug deposited in the stage 2 and the respirable dose for RG-halers were similar to those of ISF inhalator® and significantly (P<0.05 higher than those of Rotahaler® and Spinhaler®. The results suggest efficient aerosol generating capability of the RG-haler.

  14. CFD modelling of condensers for freeze-drying processes

    Indian Academy of Sciences (India)

    Miriam Petitti; Antonello A Barresi; Daniele L Marchisio

    2013-12-01

    The aim of the present research is the development of a computational tool for investigating condensation processes and equipment with particular attention to freeze-dryers. These condensers in fact are usually operated at very low pressures, making it difficult to experimentally acquire quantitative knowledge of all the variables involved. Mathematical modelling and CFD (Computational Fluid Dynamics) simulations are used here to achieve a better comprehension of the flow dynamics and of the process of ice condensation and deposition in the condenser, in order to evaluate condenser efficiency and gain deeper insights of the process to be used for the improvement of its design. Both a complete laboratory-scale freeze-drying apparatus and an industrial-scale condenser have been investigated in this work, modelling the process of water vapour deposition. Different operating conditions have been considered and the influence exerted by the inert gas as well as other parameters has been investigated.

  15. Acid deposition in the United Kingdom 1992-1994. Fourth report of the Review Group on Acid Rain

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-06-01

    The fourth report in the series examines the nature and extent of acid deposition throughout the United Kingdom. Topics are covered under the following headings: emissions of air pollutants leading to acidification, atmospheric transport and chemical conversion of acidifying air pollutants; wet deposition; concentrations of gases and particles; dry deposition processes, spatial patterns and recent trends; cloud droplet interception; total deposition; modelling of acid deposition in the United Kingdom; changes in concentrations and deposition of acidifying pollutants over the United Kingdom; and conclusions and recommendations. While emissions of SO{sub 2} are falling, emissions of nitrogen oxides have remained fairly constant since 1970. 240 refs., 128 figs., 34 tabs., 5 apps.

  16. Solar drying of jack fruit almonds

    OpenAIRE

    Alexandre J. de M. Queiroz; Dantas,Hermeval J; Figueirêdo,Rossana M. F. de; Karla dos S Melo

    2011-01-01

    Dryers heated by solar energy have been constructed and used in drying whole and half jack fruit almonds. The samples were dried during the day in direct sun and in the conventional solar dryer prepared for this purpose. Another piece of equipment was built for reception and accumulation of sun energy in a body of water, which was used as a heat source for night drying. The drying with the sun energy was compared with artificial drying. The jack fruit almonds were dried whole, half, with pell...

  17. Magnetic field switchable dry adhesives.

    Science.gov (United States)

    Krahn, Jeffrey; Bovero, Enrico; Menon, Carlo

    2015-02-01

    A magnetic field controllable dry adhesive device is manufactured. The normal adhesion force can be increased or decreased depending on the presence of an applied magnetic field. If the magnetic field is present during the entire normal adhesion test cycle which includes both applying a preloading force and measuring the pulloff pressure, a decrease in adhesion is observed when compared to when there is no applied magnetic field. Similarly, if the magnetic field is present only during the preload portion of the normal adhesion test cycle, a decrease in adhesion is observed because of an increased stiffness of the magnetically controlled dry adhesive device. When the applied magnetic field is present during only the pulloff portion of the normal adhesion test cycle, either an increase or a decrease in normal adhesion is observed depending on the direction of the applied magnetic field.

  18. Drying characteristics of ultrasound assisted hot air drying of Flos Lonicerae

    OpenAIRE

    LIU, YUNHONG; Sun, Yue; Miao, Shuai; Li, Fang; Luo, Denglin

    2014-01-01

    Ultrasound assisted hot air drying of Flos Lonicerae was investigated in this study. The effects of drying parameters such as ultrasonic radiation distance, ultrasonic power and drying temperature on drying characteristics were discussed. The results showed that ultrasound application has positive and significant effects on hot air drying. Shortening ultrasonic radiation distance is beneficial to improve both ultrasonic energy efficiency and drying rate. Higher ultrasonic power had more posit...

  19. Drying poly(ethylene glycol)

    OpenAIRE

    sprotocols

    2015-01-01

    Authors: Lucas Kinard, Kurtis Kasper & Antonios Mikos ### Abstract This protocol describes the drying of poly(ethylene glycol) (PEG) by a simple 6 step procedure. One can implement this protocol using common lab glass and lab equipment. Water is removed from PEG by azeotropic distillation in toluene. The two components are mixed and toluene and water are distilled off by heating the solution to 170°C. This procedure can be implemented in ~2 h. ### Introduction In many ...

  20. 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.

  1. 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...

  2. 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...

  3. 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...

  4. Chemically deposited tin sulphide

    Energy Technology Data Exchange (ETDEWEB)

    Akkari, A., E-mail: anis.akkari@ies.univ-montp2.f [Laboratoire de Physique de la Matiere Condensee, Faculte des Sciences de Tunis El Manar, Tunisie 2092 (Tunisia); Institut d' Electronique du Sud, Unite Mixte de Recherche 5214 UM2-CNRS (ST2i), Universite Montpellier 2, Place Eugene Bataillon, CC 082, 34095 Montpellier Cedex 5 (France); Guasch, C. [Institut d' Electronique du Sud, Unite Mixte de Recherche 5214 UM2-CNRS (ST2i), Universite Montpellier 2, Place Eugene Bataillon, CC 082, 34095 Montpellier Cedex 5 (France); Kamoun-Turki, N. [Laboratoire de Physique de la Matiere Condensee, Faculte des Sciences de Tunis El Manar, Tunisie 2092 (Tunisia)

    2010-02-04

    SnS thin films were deposited on glass substrates after multi-deposition runs by chemical bath deposition from aqueous solution containing 30 ml triethanolamine (TEA) (C{sub 6}H{sub 15}NO{sub 3}) (50%), 10 ml thioacetamide (CH{sub 3}CSNH{sub 2}), 8 ml ammonia (NH{sub 3}) solution and 10 ml of Sn{sup 2+}(0.1 M). These films were characterised with X-ray diffraction (XRD), with scanning electron microscopy, and with spectrophotometric measurements. The obtained thin films exhibit the zinc blend structure, the crystallinity seems to be improved as the film thickness increases and the band gap energy is found to be about 1.76 eV for film prepared after six depositions runs.

  5. Long-term assessment of nitrogen deposition at remote EANET sites in Japan

    Science.gov (United States)

    Ban, Satomi; Matsuda, Kazuhide; Sato, Keiichi; Ohizumi, Tsuyoshi

    2016-12-01

    Atmospheric emissions of reactive nitrogen have increased significantly on a global scale due to increases of the use of artificial fertilizer and the burning of fossil fuels. The Asian region has been identified as a high-risk area for nitrogen deposition effects on ecosystems. This paper describes a measurement-based assessment of nitrogen deposition carried out in cooperation with the Acid Deposition Monitoring Network in East Asia (EANET). The investigation aimed to understand the status and variability of dry, wet and total deposition of oxidized and reduced nitrogen over a 10-year period (2003-2012) at 8 remote sites in Japan (Rishiri, Tappi, Sado-seki, Happo, Oki, Yusuhara, Ogasawara and Hedo). Dry deposition amounts were estimated by the inferential method. All of the sites except Rishiri and Ogasawara had high mean annual total nitrogen deposition amounts of approximately 10 kg N ha-1 year-1 or more, over the 10-year period. The high contribution of oxidized nitrogen deposition in the central area is mainly caused by domestic emissions, especially for dry deposition processes. An increase in reduced nitrogen deposition originating from regional emissions was found, and is likely to result in a subsequent increase in the total nitrogen deposition in Japan. Since neither a clear increasing nor decreasing trend in total nitrogen deposition was found at any site during the 10-year period, the nitrogen deposition amounts remained high thorough the long period in Japanese remote area. The spatial distribution of nitrogen deposition was found to be significant when uncertainties were accounted for.

  6. Uniaxial tension of drying sieves

    Directory of Open Access Journals (Sweden)

    Bojić Nada V.

    2013-01-01

    Full Text Available Although the literature contains numerous studies that have been developed to describe the nonlinear behavior of drying sieves' operation, there are no papers in this which report deeper investigation of the drying sieve behavior when exposed to tension and thermo stabilization. The aim of this paper is to provide insight into the elastoplastic behavior of the thermo stabilized and not stabilized sieves subjected to the tensile force. Within this work both theoretical and experimental investigations were performed. The sieves were joined by using a spiral. In separate experiments tests of wire base and weft of the weave mesh were performed, both for thermo stabilized and not thermo stabilized sieves, sieves joining and the sieve thermo stabilization itself. It was established that the thermo stabilization of sieves provides for stability of sieves' dimensions and that open thermo stabilized drying sieve exhibits better mechanical properties and exploitation characteristics then the sieves joining. [Projekat Ministarstva nauke Republike Srbije, br. ON174004: Micromechanics criteria of damage and fracture and br. TR 32036: Development of software for solving the coupled multi-physical problems

  7. Evaluating urban runoff pollution: sediments deposited on a road surface

    Directory of Open Access Journals (Sweden)

    Carlos Alfonso Zafra Mejía

    2010-11-01

    Full Text Available The pollution caused by runoff water continues being a great problem in urban areas. Studying the behavior of sediments depo-sited on a road surface serves to determine the characteristics of their build-up during dry times and wash-off during rainy pe-riods. It will also lead to establishing pollution control mechanisms associated with the sediment deposited on particular types of road surfaces. This paper presents data regarding the sediment accumulating on a road surface in the city of Torrelavega in northern Spain during a 65-day period, during which time 132 samples were collected. Two types of sediment collection samples were obtained: vacuumed dry samples (free load and those swept up following vacuuming (fixed load. Sediment loading, particle size distribution and moisture were determined for each type of sample. The data showed that the sediment loading (gm−2 and vacuumed availability of the load which adhered most strongly to the surface (fixed load increased with the number of dry days. Collected sediment particle size distribution tended to be finer with the increase in the number of dry days. <125 μm particle sizes presented the greatest rate of build-up during dry time and those which were <500 μm had the greatest susceptibi-lity to being washed off during rain.

  8. Electrospark deposition coatings

    Science.gov (United States)

    Sheely, W. F.

    1986-11-01

    Hard surfacing for wear resistant and low-friction coatings has been improved by means of advances in the computer controls in electronic circuitry of the electrospark deposition (ESD) process. coatings of nearly any electrically conductive metal alloy or cermet can be deposited on conductive materials. Thickness is usually two mils or less, but can be as high as 10 mils. ESD coatings can quadrupole cutting tool life.

  9. Gemstone deposits of Serbia

    Science.gov (United States)

    Miladinović, Zoran; Simić, Vladimir; Jelenković, Rade; Ilić, Miloje

    2016-06-01

    Gemstone minerals in Serbia have never been regarded as an interesting and significant resource. Nevertheless, more than 150 deposits and occurrences have been recorded and some of them preliminarily explored in the last 50 years. The majority of deposits and occurrences are located within the Serbo-Macedonian metallogenic province and the most significant metallogenic units at the existing level of knowledge are the Fruska Gora ore district, Cer ore district, Sumadija metallogenic zone, Kopaonik metallogenic zone and Lece-Halkidiki metallogenic zone. The most important genetic type of deposits is hydrothermal, particularly in case of serpentinite/peridotite as host/parent rock. Placer deposits are also economically important. The dominant gemstones are silica minerals: chalcedony (Chrysoprase, carnelian, bluish chalcedony etc.), jasper (picture, landscape, red etc.), common opal (dendritic, green, milky white etc.), silica masses (undivided), and quartz (rock crystal, amethyst etc.). Beside silica minerals significant gemstones in Serbia include also beryl (aquamarine), garnet (almandine and pyrope), tourmaline, fluorite, rhodochrosite, carbonate-silica breccia, carbonate-silica onyx, silicified wood, howlite, serpentinite, marble onyx, and kyanite. This paper aims to present an overview of Serbian gemstone deposits and occurrences and their position based on a simplified gemstone metallogenic map of Serbia, as well as genetic-industrial classification of gemstone deposits and gemstone varieties.

  10. Gemstone deposits of Serbia

    Directory of Open Access Journals (Sweden)

    Miladinović Zoran

    2016-06-01

    Full Text Available Gemstone minerals in Serbia have never been regarded as an interesting and significant resource. Nevertheless, more than 150 deposits and occurrences have been recorded and some of them preliminarily explored in the last 50 years. The majority of deposits and occurrences are located within the Serbo-Macedonian metallogenic province and the most significant metallogenic units at the existing level of knowledge are the Fruska Gora ore district, Cer ore district, Sumadija metallogenic zone, Kopaonik metallogenic zone and Lece-Halkidiki metallogenic zone. The most important genetic type of deposits is hydrothermal, particularly in case of serpentinite/peridotite as host/parent rock. Placer deposits are also economically important. The dominant gemstones are silica minerals: chalcedony (Chrysoprase, carnelian, bluish chalcedony etc., jasper (picture, landscape, red etc., common opal (dendritic, green, milky white etc., silica masses (undivided, and quartz (rock crystal, amethyst etc.. Beside silica minerals significant gemstones in Serbia include also beryl (aquamarine, garnet (almandine and pyrope, tourmaline, fluorite, rhodochrosite, carbonate-silica breccia, carbonate-silica onyx, silicified wood, howlite, serpentinite, marble onyx, and kyanite. This paper aims to present an overview of Serbian gemstone deposits and occurrences and their position based on a simplified gemstone metallogenic map of Serbia, as well as genetic-industrial classification of gemstone deposits and gemstone varieties.

  11. Heavy metal atmospheric deposition and biomonitoring

    Science.gov (United States)

    Ayrault, S.; Clocchiatti, R.; Carrot, F.; Michel, A.; Gaudry, A.; Moskura, M.

    2003-05-01

    The atmospheric fluxes of heavy metals were measured continuously in the Paris area. The dry depositions were collected on quartz fiber filters, after comparison between clogging capacities and blank levels on commercial filters. Rain was collected in a polyethylene gauge. Two transplanted biomonitors, the epiphytic lichen Evernia prunastri, and the pleurocarpeous moss Scleropodium purum, were exposed simultaneously. These two common biomonitors have been used in previous passive biomonitoring campaigns [Galsomies 1999, Grasso 1999]. This work attempts to produce data on heavy metal exposure of this populated area near Paris, and to compare these two cryptogamic species behaviour. The results on bioaccumulation were compared to those given by a previous work in Italy [Bargagli, 2002] comparing the moss Hypnum cupressiforme and the lichen Parmelia caperata. In our study, the transplanted lichens were exposed in different conditions: to the rain or protected from rain, in vertical, horizontal or oblique position. Dry (filters) and wet (rain) depositions and biomonitors were analysed by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) and Neutron Activation Analysis (NAA) for more than 30elements [Ayrault, 2001]. The individual particle composition (on filters and cryptogams) was determined by nuclear microprobe (PIXE) and electron microprobe. The lichens displayed different accumulation rates, depending on exposition conditions. In particular, the inclination influenced the bulk concentrations in the lichen. Relation was made between fluxes and concentration accumulated by the biomonitors. The enrichment factors were spectacular for some elements, e.g. lead.

  12. DRYING WITH SOLAR COLLECTOR BY HEAT PIPE

    Directory of Open Access Journals (Sweden)

    Hikmet DOĞAN

    1999-01-01

    Full Text Available In this research, heating pipe was used in the solar collector in order to take better advantage of the solar energy. The energy obtained from the sun was transferred to the drying air by means of heating pipes and this hot air was blown on the material to be dried. The water on the material to be dried vaporised with the effect of the hot air and drying took place. Because drying took place in the shade, distant from the direct radiation effects of the sun, some of the disadvantages seen in drying outside, under the sun were eliminated. Additionally, it was observed that it took less time to dry in this method than it takes to dry under the open sun.

  13. ENVIRONMENTAL ASPECTS OF THE INTENSIFICATION CONVECTIVE DRYING

    Directory of Open Access Journals (Sweden)

    A. M. Gavrilenkov

    2012-01-01

    Full Text Available Identified and analyzed the relationship of the intensity convective drying and air pollution emissions of heat. The ways to reduce the thermal pollution of the atmosphere at convective drying.

  14. Dry needling — peripheral and central considerations

    OpenAIRE

    Dommerholt, Jan

    2011-01-01

    Dry needling is a common treatment technique in orthopedic manual physical therapy. Although various dry needling approaches exist, the more common and best supported approach targets myofascial trigger points. This article aims to place trigger point dry needling within the context of pain sciences. From a pain science perspective, trigger points are constant sources of peripheral nociceptive input leading to peripheral and central sensitization. Dry needling cannot only reverse some aspects...

  15. Atmospheric deposition of polycyclic aromatic hydrocarbons (PAHs) in Shanghai: the spatio-temporal variation and source identification

    Science.gov (United States)

    Cheng, Chen; Bi, Chunjuan; Wang, Dongqi; Yu, Zhongjie; Chen, Zhenlou

    2017-01-01

    This study investigated the dry and wet deposition fluxes of atmospheric polycyclic aromatic hydrocarbons (PAHs) in Shanghai, China. The flux sources were traced based on composition and spatio-temporal variation. The results show that wet deposition concentrations of PAHs ranged from 0.07 to 0.67 mg·L-1 and were correlated with temperature (PPAHs concentrations ranged from 3.60-92.15 mg·L-1 and were higher in winter and spring than in summer and autumn. The annual PAH average fluxes were 0.631 mg·m-2·d-1 and 4.06 mg·m-2·d-1 for wet and dry deposition, respectively. The highest wet deposition of PAH fluxes was observed in summer, while dry deposition fluxes were higher in winter and spring. Atmospheric PAHs were deposited as dry deposition in spring and winter, yet wet deposition was the dominant pathway during summer. Total atmospheric PAH fluxes were higher in the northern areas than in the southern areas of Shanghai, and were also observed to be higher in winter and spring. Annual deposition of atmospheric PAHs was about 10.8 t in across all of Shanghai. Wet deposition of PAHs was primarily composed of two, three, or four rings, while dry deposition of PAHs was composed of four, five, or six rings. The atmospheric PAHs, composed of four, five, or six rings, primarily existed in the form of particulates. Coal combustion and vehicle emissions were the dominant sources of PAH in the observed area of downtown Shanghai. In suburban areas, industrial pollution, from sources such as coke oven, incinerator, and oil fired power plant, was as significant as vehicle emissions in contributing to the deposition of PAHs.

  16. Atmospheric inorganic nitrogen deposition to a typical red soil forestland in southeastern China.

    Science.gov (United States)

    Fan, Jian-Ling; Hu, Zheng-Yi; Wang, Ti-Jian; Zhou, Jing; Wu, Cong-Yang-Hui; Xia, Xu

    2009-12-01

    A 2-year monitoring study was conducted to estimate nitrogen deposition to a typical red soil forestland in southeastern China. The dry deposition velocities (V(d)) were estimated using big leaf resistance analogy model. Atmospheric nitrogen dry deposition was estimated by combing V(d) and nitrogen compounds concentrations, and the wet deposition was calculated via rainfall and nitrogen concentrations in rainwater. The total inorganic nitrogen deposition was 83.7 kg ha(-1) a(-1) in 2004 and 81.3 kg ha(-1) a(-1) in 2005, respectively. The dry deposition contributed 78.6% to total nitrogen deposition, in which ammonia was the predominant contributor that accounted for 86.1%. Reduced nitrogen compounds were the predominant contributors, accounting for 78.3% of total nitrogen deposition. The results suggested that atmospheric inorganic nitrogen could be attributed to intensive agricultural practices such as excessive nitrogen fertilization and livestock production. Therefore, impacts of atmospheric nitrogen originated from agriculture practices on nearby forest ecosystems should be evaluated.

  17. Nitrogen deposition effects on Mediterranean-type ecosystems: An ecological assessment

    Energy Technology Data Exchange (ETDEWEB)

    Ochoa-Hueso, Raul, E-mail: raul.ochoa@ccma.csic.es [Department of Plant Physiology and Ecology, Centro de Ciencias Medioambientales, Consejo Superior de Investigaciones Cientificas, C/Serrano 115 Dpdo., 28006 Madrid (Spain); Allen, Edith B. [Department of Botany and Plant Sciences and Center for Conservation Biology, University of California, Riverside, CA 92521 (United States); Branquinho, Cristina; Cruz, Cristina; Dias, Teresa [Universidade de Lisboa, Faculdade de Ciencias, Centro de Biologia Ambiental, Campo Grande, Bloco C4, 1749-016 Lisboa (Portugal); Fenn, Mark E. [US Department of Agriculture (USDA) Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Drive, Riverside, CA 92507 (United States); Manrique, Esteban [Department of Plant Physiology and Ecology, Centro de Ciencias Medioambientales, Consejo Superior de Investigaciones Cientificas, C/Serrano 115 Dpdo., 28006 Madrid (Spain); Perez-Corona, M. Esther [Department of Ecology, Faculty of Biology, Universidad Complutense de Madrid, C/Jose Antonio Novais 2, 28040 Madrid (Spain); Sheppard, Lucy J. [Centre of Ecology and Hydrology, Bush Estate, Penicuik EH26 0QB (United Kingdom); Stock, William D. [Centre for Ecosystem Management, School of Natural Sciences, Edith Cowan University, 100 Joondalup Drive, Joondalup, Perth, WA 6027 (Australia)

    2011-10-15

    We review the ecological consequences of N deposition on the five Mediterranean regions of the world. Seasonality of precipitation and fires regulate the N cycle in these water-limited ecosystems, where dry N deposition dominates. Nitrogen accumulation in soils and on plant surfaces results in peaks of availability with the first winter rains. Decoupling between N flushes and plant demand promotes losses via leaching and gas emissions. Differences in P availability may control the response to N inputs and susceptibility to exotic plant invasion. Invasive grasses accumulate as fuel during the dry season, altering fire regimes. California and the Mediterranean Basin are the most threatened by N deposition; however, there is limited evidence for N deposition impacts outside of California. Consequently, more research is needed to determine critical loads for each region and vegetation type based on the most sensitive elements, such as changes in lichen species composition and N cycling. - Highlights: > N deposition impacts are understudied in Mediterranean ecosystems out of California. > Dry N deposition is dominant and N flushes are common after rainless periods. > Water availability and P fertility regulate ecosystem responses to N deposition. > Research is needed to determine critical loads for each region and vegetation type. - Nitrogen deposition threatens the Mediterranean regions of the world.

  18. Drying and color characteristics of coriander foliage using convective thin-layer and microwave drying.

    Science.gov (United States)

    Shaw, Mark; Meda, Venkatesh; Tabil, Lope; Opoku, Anthony

    2007-01-01

    Heat sensitive properties (aromatic, medicinal, color) provide herbs and spices with their high market value. In order to prevent extreme loss of heat sensitive properties when drying herbs, they are normally dried at low temperatures for longer periods of time to preserve these sensory properties. High energy consumption often results from drying herbs over a long period. Coriander (Coriandrum sativum L., Umbelliferae) was dehydrated in two different drying units (thin layer convection and microwave dryers) in order to compare the drying and final product quality (color) characteristics. Microwave drying of the coriander foliage was faster than convective drying. The entire drying process took place in the falling rate period for both microwave and convective dried samples. The drying rate for the microwave dried samples ranged from 42.3 to 48.2% db/min and that of the convective dried samples ranged from 7.1 to 12.5% db/min. The fresh sample color had the lowest L value at 26.83 with higher L values for all dried samples. The results show that convective thin layer dried coriander samples exhibited a significantly greater color change than microwave dried coriander samples. The color change index values for the microwave dried samples ranged from 2.67 to 3.27 and that of the convective dried samples varied from 4.59 to 6.58.

  19. energetic performance analysis of drying agricultural products ...

    African Journals Online (AJOL)

    user

    1,2,3,4DEPARTMENT OF MECHANICAL ENGINEERING, UNIVERSITY OF ILORIN, P.M.B. 1515, ILORIN, ... drying and moldy food [9]. ... solar drying systems diversely in operation are ... 2.1 Useful Energy Required for Drying A Unit Amount.

  20. 21 CFR 131.149 - Dry cream.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Dry cream. 131.149 Section 131.149 Food and Drugs... CONSUMPTION MILK AND CREAM Requirements for Specific Standardized Milk and Cream § 131.149 Dry cream. (a) Description. Dry cream is the product obtained by removal of water only from pasteurized milk or cream or...

  1. Drying of willow biomass in supply chains

    NARCIS (Netherlands)

    Gigler, J.K.

    2000-01-01

    The drying process of willow ( Salix viminalis ) in biomass supply chains to energy plants is quantitatively described. Drying at particle level was modelled for chips and stems by a diffusion equation linked to the mass transfer of moisture to the air. Drying at bulk level is described by a deep be

  2. Drying of willow biomass in supply chains

    NARCIS (Netherlands)

    Gigler, J.

    2000-01-01

    The drying process of willow ( Salix viminalis ) in biomass supply chains to energy plants is quantitatively described. Drying at particle level was modelled for chips and stems by a diffusion equation linked to the mass transfer of moisture to the air. Drying at bulk

  3. Increasing importance of deposition of reduced nitrogen in the United States.

    Science.gov (United States)

    Li, Yi; Schichtel, Bret A; Walker, John T; Schwede, Donna B; Chen, Xi; Lehmann, Christopher M B; Puchalski, Melissa A; Gay, David A; Collett, Jeffrey L

    2016-05-24

    Rapid development of agriculture and fossil fuel combustion greatly increased US reactive nitrogen emissions to the atmosphere in the second half of the 20th century, resulting in excess nitrogen deposition to natural ecosystems. Recent efforts to lower nitrogen oxides emissions have substantially decreased nitrate wet deposition. Levels of wet ammonium deposition, by contrast, have increased in many regions. Together these changes have altered the balance between oxidized and reduced nitrogen deposition. Across most of the United States, wet deposition has transitioned from being nitrate-dominated in the 1980s to ammonium-dominated in recent years. Ammonia has historically not been routinely measured because there are no specific regulatory requirements for its measurement. Recent expansion in ammonia observations, however, along with ongoing measurements of nitric acid and fine particle ammonium and nitrate, permit new insight into the balance of oxidized and reduced nitrogen in the total (wet + dry) US nitrogen deposition budget. Observations from 37 sites reveal that reduced nitrogen contributes, on average, ∼65% of the total inorganic nitrogen deposition budget. Dry deposition of ammonia plays an especially key role in nitrogen deposition, contributing from 19% to 65% in different regions. Future progress toward reducing US nitrogen deposition will be increasingly difficult without a reduction in ammonia emissions.

  4. Pulsed laser deposition: Prospects for commercial deposition of epitaxial films

    Energy Technology Data Exchange (ETDEWEB)

    Muenchausen, R.E.

    1999-03-01

    Pulsed laser deposition (PLD) is a physical vapor deposition (PVD) technique for the deposition of thin films. The vapor source is induced by the flash evaporation that occurs when a laser pulse of sufficient intensity (about 100 MW/cm{sup 2}) is absorbed by a target. In this paper the author briefly defines pulsed laser deposition, current applications, research directed at gaining a better understanding of the pulsed laser deposition process, and suggests some future directions to enable commercial applications.

  5. ZrN coatings deposited by high power impulse magnetron sputtering and cathodic arc techniques

    Energy Technology Data Exchange (ETDEWEB)

    Purandare, Yashodhan, E-mail: Y.Purandare@shu.ac.uk; Ehiasarian, Arutiun; Hovsepian, Papken [Nanotechnology Centre for PVD Research, Materials and Engineering Research Institute, Sheffield Hallam University, Sheffield S1 1WB (United Kingdom); Santana, Antonio [Ionbond AG Olten, Industriestrasse 211, CH-4600 Olten (Switzerland)

    2014-05-15

    Zirconium nitride (ZrN) coatings were deposited on 1 μm finish high speed steel and 316L stainless steel test coupons. Cathodic Arc (CA) and High Power Impulse Magnetron Sputtering (HIPIMS) + Unbalanced Magnetron Sputtering (UBM) techniques were utilized to deposit coatings. CA plasmas are known to be rich in metal and gas ions of the depositing species as well as macroparticles (droplets) emitted from the arc sports. Combining HIPIMS technique with UBM in the same deposition process facilitated increased ion bombardment on the depositing species during coating growth maintaining high deposition rate. Prior to coating deposition, substrates were pretreated with Zr{sup +} rich plasma, for both arc deposited and HIPIMS deposited coatings, which led to a very high scratch adhesion value (L{sub C2}) of 100 N. Characterization results revealed the overall thickness of the coatings in the range of 2.5 μm with hardness in the range of 30–40 GPa depending on the deposition technique. Cross-sectional transmission electron microscopy and tribological experiments such as dry sliding wear tests and corrosion studies have been utilized to study the effects of ion bombardment on the structure and properties of these coatings. In all the cases, HIPIMS assisted UBM deposited coating fared equal or better than the arc deposited coatings, the reasons being discussed in this paper. Thus H+U coatings provide a good alternative to arc deposited where smooth, dense coatings are required and macrodroplets cannot be tolerated.

  6. Single droplet drying for optimal spray drying of enzymes and probiotics

    NARCIS (Netherlands)

    Schutyser, M.A.I.; Perdana, J.A.; Boom, R.M.

    2012-01-01

    Spray drying is a mild and cost-effective convective drying method. It can be applied to stabilise heat sensitive ingredients, such as enzymes and probiotic bacteria, albeit in industrial practice for example freeze drying or freezing are often preferred. The reason is that optimum drying conditions

  7. Dry Transfer Systems for Used Nuclear Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Brett W. Carlsen; Michaele BradyRaap

    2012-05-01

    The potential need for a dry transfer system (DTS) to enable retrieval of used nuclear fuel (UNF) for inspection or repackaging will increase as the duration and quantity of fuel in dry storage increases. This report explores the uses for a DTS, identifies associated general functional requirements, and reviews existing and proposed systems that currently perform dry fuel transfers. The focus of this paper is on the need for a DTS to enable transfer of bare fuel assemblies. Dry transfer systems for UNF canisters are currently available and in use for transferring loaded canisters between the drying station and storage and transportation casks.

  8. Friction and wear behavior of electrodeposited amorphous Fe-Co-W alloy deposits

    Institute of Scientific and Technical Information of China (English)

    何凤姣; 雷惊天; 陆欣; 黄宇宁

    2004-01-01

    The microstructures, friction and wear behavior under dry sliding condition of electrodeposited amorphous Fe-Co-W alloy deposits heat treated at different temperatures were studied. A comparative study of hard chrome deposit under the same testing condition was also made. The experimental results show that the hardness and wear resistance of amorphous Fe-Co-W alloy deposits are improved with the increasing of heat treatment temperature, and reach the maximum value at 800 ℃, then decrease above 800 ℃. Under 40 N load, the wear resistance properties of the alloy deposits heat treated at 800 ℃ are superior to those of hard chrome deposit. The main wear mechanisms of amorphous Fe-Co-W alloy deposits heat treated below 600 ℃ are peeling, plastic and flowing deformation; when the deposits are heat treated above 700 ℃, they are plastic and flowing deformation. While the main wear mechanisms of hard chrome are abrasive wear, fatigue and peeling.

  9. Modeling multiple resource limitation in tropical dry forests

    Science.gov (United States)

    Medvigy, D.; Xu, X.; Zarakas, C.

    2015-12-01

    Tropical dry forests (TDFs) are characterized by a long dry season when little rain falls. At the same time, many neotropical soils are highly weathered and relatively nutrient poor. Because TDFs are often subject to both water and nutrient constraints, the question of how they will respond to environmental perturbations is both complex and highly interesting. Models, our basic tools for projecting ecosystem responses to global change, can be used to address this question. However, few models have been specifically parameterized for TDFs. Here, we present a new version of the Ecosystem Demography 2 (ED2) model that includes a new parameterization of TDFs. In particular, we focus on the model's framework for representing limitation by multiple resources (carbon, water, nitrogen, and phosphorus). Plant functional types are represented in terms of a dichotomy between "acquisitive" and "conservative" resource acquisition strategies. Depending on their resource acquisition strategy and basic stoichiometry, plants can dynamically adjust their allocation to organs (leaves, stem, roots), symbionts (e.g. N2-fixing bacteria), and mycorrhizal fungi. Several case studies are used to investigate how resource acquisition strategies affect ecosystem responses to environmental perturbations. Results are described in terms of the basic setting (e.g., rich vs. poor soils; longer vs. shorter dry season), and well as the type and magnitude of environmental perturbation (e.g., changes in precipitation or temperature; changes in nitrogen deposition). Implications for ecosystem structure and functioning are discussed.

  10. Drying grain using a hydrothermally treated liquid lignite fuel

    Energy Technology Data Exchange (ETDEWEB)

    Bukurov, Z.; Cvijanovic, P.; Bukurov, M. [Univ. of Novi Sad (Yugoslavia); Ljubicic, B.R. [Univ. of North Dakota, Grand Forks, ND (United States)

    1995-12-01

    A shortage of domestic oil and natural gas resources in Yugoslavia, particularly for agricultural and industrial purposes, has motivated the authors to explore the possibility of using liquid lignite as an alternate fuel for drying grain. This paper presents a technical and economic assessment of the possibility of retrofitting grain-drying plants currently fueled by oil or natural gas to liquid lignite fuel. All estimates are based on lignite taken from the Kovin deposit. Proposed technology includes underwater mining techniques, aqueous ash removal, hydrothermal processing, solids concentration, pipeline transport up to 120 km, and liquid lignite direct combustion. For the characterization of Kovin lignite, standard ASTM procedures were used: proximate, ultimate, ash, heating value, and Theological analyses were performed. Results from an extensive economic analysis indicate a delivered cost of US$20/ton for the liquid lignite. For the 70 of the grain-drying plants in the province of Vojvodina, this would mean a total yearly saving of about US $2,500,000. The advantages of this concept are obvious: easy to transport and store, nonflammable, nonexplosive, nontoxic, 30%-40% cheaper than imported oil and gas, domestic fuel is at hand. The authors believe that liquid lignite, rather than an alternative, is becoming more and more an imperative.

  11. Pulsed laser deposition of lysozyme: the dependence on shot numbers and the angular distribution

    DEFF Research Database (Denmark)

    Constantinescu, C.; Matei, A.; Schou, Jørgen

    2013-01-01

    . This was verified by matrix-assisted laser desorption ionization (MALDI) spectrometry of thin films deposited on silicon substrates. The deposition rate of lysozyme was found to decrease with the number of shots and was correlated with increasing thermal damage of the lysozyme. This was monitored by measurements...... of the optical reflectivity of dry lysozyme. The angular distribution of the mass deposition can be fitted well by Anisimov’s hydrodynamic model. The total deposited yield over the entire hemisphere from direct laser ablation of lysozyme was estimated from this model and found to be three orders of magnitude...

  12. Impregnation of leather during "freeze-drying"

    DEFF Research Database (Denmark)

    Storch, Mikkel; Vestergaard Poulsen Sommer, Dorte; Hovmand, Ida

    2016-01-01

    Freeze-drying is a recognized method for the preservation of waterlogged objects. Naturally, freeze-drying has also been used for waterlogged archaeological leather often after treatment with Na2.EDTA and impregnation with PEG; but the treated leather sometimes suffers from “excessive drying......” becoming too stiff and brittle. The aim of this study was to examine the effect of a conventional freeze-drying method against an alternative freeze-drying method that preserves the natural moisture content of the leather. Both new and archaeological waterlogged leather were included in the study...... suggest that the process which takes place within the leather during the freeze-drying in not actual freeze-drying, but rather a sophisticated way of distributing the impregnating agent. The pure ice phase freezes out, but the impregnating agent remains liquid as the temperature does not become low enough...

  13. Characteristic Drying Curve of Oil Palm Fibers

    Directory of Open Access Journals (Sweden)

    Ifa Puspasari

    2014-03-01

    Full Text Available The drying of crushed oil palm fronds was studied in a fluidized bed dryer assisted with mechanical agitation at different inlet air temperature, superficial air velocity, bed loading and agitation speed. The drying kinetics of the fibers under various drying conditions could be described by a single characteristic drying curve. A combined exponential and power law model is proposed to represent the characteristic drying curve which described both the increasing rate and the falling rate periods. The proposed model is also tested for drying kinetics of oil palm empty fruit bunch from previous researcher. It was found that the characteristic curve for both oil palm fronds and empty fruit bunch fibers has similar shape and that the proposed model is acceptable for describing the complete drying characteristics of the fibers.

  14. Dry spell frequency in West Java, Indonesia

    Science.gov (United States)

    Purnaningtyas, V. I.; Boer, R.; Faqih, A.

    2017-03-01

    The climatology and variability of dry spells are valuable information for scientists, engineers, planners, and managers working in water-related sectors such as agriculture, ecology, hydrology, and water resources. The dry spell concerns consecutive dry days which are the largest number of consecutive days with less than 1 mm of daily precipitation within a year. The objective of this study is to analyse the spatial and temporal characteristics of dry spells and also specifically investigate the frequency patterns of the dry spell distribution based on historical observed daily precipitation from 1981 to 2010. The longest dry spell occured at Pasirukem with the length of 252 days. The northern coast of West Java have higher probabilities of dry spells more than 5, 10, 15, and 20 days.

  15. Acousto-Convective Drying of Pine Nuts

    Science.gov (United States)

    Zhilin, A. A.; Fedorov, A. V.

    2014-07-01

    An experimental investigation of the process of drying pine nut grains has been carried out by three methods: acousto-convective, thermoconvective, and thermal. A qualitative and a quantitative comparison of the dynamics of the processes of moisture extraction from the nut grains for the considered drying methods have been made. To elucidate the mechanism of moisture extraction from the pine nut grains, we carried out a separate investigation of the process of drying the nut shell and the kernel. The obtained experimental data on the acousto-convective drying of nuts are well described by the relaxation model, the data on the thermoconvective drying are well described by the bilinear law, and the data on the thermal drying are well described by the combined method consisting of three time steps characterized by different kinetic regimes of drying.

  16. Dry etching technology for semiconductors

    CERN Document Server

    Nojiri, Kazuo

    2015-01-01

    This book is a must-have reference to dry etching technology for semiconductors, which will enable engineers to develop new etching processes for further miniaturization and integration of semiconductor integrated circuits.  The author describes the device manufacturing flow, and explains in which part of the flow dry etching is actually used. The content is designed as a practical guide for engineers working at chip makers, equipment suppliers and materials suppliers, and university students studying plasma, focusing on the topics they need most, such as detailed etching processes for each material (Si, SiO2, Metal etc) used in semiconductor devices, etching equipment used in manufacturing fabs, explanation of why a particular plasma source and gas chemistry are used for the etching of each material, and how to develop etching processes.  The latest, key technologies are also described, such as 3D IC Etching, Dual Damascene Etching, Low-k Etching, Hi-k/Metal Gate Etching, FinFET Etching, Double Patterning ...

  17. Feasibility of spray drying bacteriophages into respirable powders to combat pulmonary bacterial infections.

    Science.gov (United States)

    Vandenheuvel, Dieter; Singh, Abhishek; Vandersteegen, Katrien; Klumpp, Jochen; Lavigne, Rob; Van den Mooter, Guy

    2013-08-01

    The use of bacterial viruses for antibacterial treatment (bacteriophage therapy) is currently being reevaluated. In this study, we analyze the potential of processing bacteriophages in a dry powder formulation, using a laboratory spray dryer. The phages were dried in the presence of lactose, trehalose or dextran 35, serving as an excipient to give the resulting powder the necessary bulk mass and offer protection to the delicate phage structure. Out of the three excipients tested, trehalose was found to be the most efficient in protecting the phages from temperature and shear stress throughout the spray drying process. A low inlet air temperature and atomizing force appeared to be the best parameter conditions for phage survival. Pseudomonas podovirus LUZ19 was remarkably stable, suffering less than 1 logarithmic unit reduction in phage titer. The phage titer of Staphyloccus phage Romulus-containing powders, a member of the Myoviridae family, showed more than 2.5 logarithmic units reduction. On the other hand, Romulus-containing powders showed more favorable characteristics for pulmonary delivery, with a high percentage of dry powder particles in the pulmonary deposition fraction (1-5 μm particle diameter). Even though the parameters were not optimized for spray drying all phages, it was demonstrated that spray drying phages with this industrial relevant and scalable set up was possible. The resulting powders had desirable size ranges for pulmonary delivery of phages with dry powder inhalers (DPIs).

  18. Reactive polymer fused deposition manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Kunc, Vlastimil; Rios, Orlando; Love, Lonnie J.; Duty, Chad E.; Johs, Alexander

    2017-05-16

    Methods and compositions for additive manufacturing that include reactive or thermosetting polymers, such as urethanes and epoxies. The polymers are melted, partially cross-linked prior to the depositing, deposited to form a component object, solidified, and fully cross-linked. These polymers form networks of chemical bonds that span the deposited layers. Application of a directional electromagnetic field can be applied to aromatic polymers after deposition to align the polymers for improved bonding between the deposited layers.

  19. Total phenolics, antioxidant capacity, colour and drying characteristics of date fruit dried with different methods

    Directory of Open Access Journals (Sweden)

    Gökçen İZLİ

    2016-01-01

    Full Text Available Abstract Date slices were dried with the three drying methods convective (60, 70 and 80 °C, microwave (120 W and freeze drying to determine drying characteristics and to compare the dried fruit quality. All colour parameters changed depending on the drying method and colours closest to the fresh sample were obtained with freeze drying. It is interesting to note that the total phenolic content and antioxidant capacity in each sample rose when looked at in relation to the fresh sample. In particular, microwave-dried samples were recorded as having the highest total phenolic content and the highest antioxidant capacity. To explain the drying kinetics of the date slices, nine thin-layer drying models were also attempted. Based on statistical tests, the model developed by Midilli et al. model was found to be the best model for convective and microwave drying, but the Two Term model was the best for freeze drying. This study shows that microwave drying can produce high quality date slices with the additional advantage of reduced drying times compared to convective and freeze drying.

  20. Atmospheric deposition of organic carbon via precipitation

    Science.gov (United States)

    Iavorivska, Lidiia; Boyer, Elizabeth W.; DeWalle, David R.

    2016-12-01

    Atmospheric deposition is the major pathway for removal of organic carbon (OC) from the atmosphere, affecting both atmospheric and landscape processes. Transfers of OC from the atmosphere to land occur as wet deposition (via precipitation) and as dry deposition (via surface settling of particles and gases). Despite current understanding of the significance of organic carbon inputs with precipitation to carbon budgets, transfers of organic matter between the atmosphere and land are not explicitly included in most carbon cycle models due to limited data, highlighting the need for further information. Studies regarding the abundance of OC in precipitation are relatively sparse, in part due to the fact that concentrations of organics in precipitation and their associated rates of atmospheric deposition are not routinely measured as a part of major deposition monitoring networks. Here, we provide a new data synthesis from 83 contemporary studies published in the peer reviewed literature where organic matter in precipitation was measured around the world. We compiled data regarding the concentrations of organic carbon in precipitation and associated rates of atmospheric deposition of organic carbon. We calculated summary statistics in a common set of units, providing insights into the magnitude and regional variability of OC in precipitation. A land to ocean gradient is evident in OC concentrations, with marine sites generally showing lower values than continental sites. Our synthesis highlights gaps in the data and challenges for data intercomparison. There is a need to concentrate sampling efforts in areas where anthropogenic OC emissions are on the rise (Asia, South America), as well as in remote sites suggesting background conditions, especially in Southern Hemisphere. It is also important to acquire more data for marine rainwater at various distances from the coast in order to assess a magnitude of carbon transfer between the land and the ocean. Our integration of

  1. Improvement in the properties of plasma-sprayed metallic, alloy and ceramic coatings using dry-ice blasting

    Science.gov (United States)

    Dong, Shujuan; Song, Bo; Hansz, Bernard; Liao, Hanlin; Coddet, Christian

    2011-10-01

    Dry-ice blasting, as an environmental-friendly method, was introduced into atmospheric plasma spraying for improving properties of metallic, alloy and ceramic coatings. The deposited coatings were then compared with coatings plasma-sprayed using conventional air cooling in terms of microstructure, temperature, oxidation, porosity, residual stress and adhesion. It was found that a denser steel or CoNiCrAlY alloy coating with a lower content of oxide can be achieved with the application of dry-ice blasting during the plasma spraying. In addition, the adhesive strength of Al 2O 3 coating deposited with dry-ice blasting exceeded 60 MPa, which was nearly increased by 30% compared with that of the coating deposited with conventional air cooling. The improvement in properties of plasma-sprayed metallic, alloy and ceramic coatings caused by dry-ice blasting was attributed to the decrease of annulus-ringed disk like splats, the better cooling efficiency of dry-ice pellets and even the mechanical effect of dry-ice impact.

  2. Atmospheric deposition of nitrogen and sulfur and preferential canopy consumption of nitrate in forests of the Pacific Northwest, USA

    Science.gov (United States)

    Mark E. Fenn; Christopher S. Ross; Susan L. Schilling; William D. Baccus; Michael A. Larrabee; Rebecca A. Lofgren

    2013-01-01

    Wet,dry and throughfall deposition of N and S were measured for 2 years in three national parks in Washington State:Olympic,Mount Rainier,and North Cascades.Throughfall was measured using ion exchange resin (IER) collectors. A major objective of the study was to evaluate the effectiveness of IER throughfall measurements for monitoring deposition inputs,including...

  3. Towards a better spatial quantification of nitrogen deposition: A case study for Czech forests.

    Science.gov (United States)

    Hůnová, Iva; Kurfürst, Pavel; Vlček, Ondřej; Stráník, Vojtěch; Stoklasová, Petra; Schovánková, Jana; Srbová, Daša

    2016-06-01

    The quantification of atmospheric deposition flux is essential for assessment of its impact on ecosystems. We present an advanced approach for the estimation of the spatial pattern of atmospheric nitrogen deposition flux over the Czech forests, collating all available measured data and model results. The aim of the presented study is to provide an improved, more complete, more reliable and more realistic estimate of the spatial pattern of nitrogen deposition flux over one country. This has so far usually been based on measurements of ambient NOx concentrations as dry deposition proxy, and [Formula: see text] and [Formula: see text] in precipitation as wet deposition proxy. For estimation of unmeasured species contributing to dry deposition, we used the CAMx Eulerian photochemical dispersion model, coupled with the Aladin regional numeric weather prediction model. The contribution of fog and dissolved organic nitrogen was estimated using a geostatistical data driven model. We prepared individual maps for particular components applying the most relevant approach and then merged all layers to obtain a final map representing the best estimate of nitrogen deposition over the Czech Republic. Final maps accounting for unmeasured species clearly indicate that the approach used so far may result in a substantial underestimation of nitrogen deposition flux. Our results showed that nitrogen deposition over the Czech forested area in 2008 was well above 2 g N m(-2) yr(-1), with almost 70% of forested area receiving 3-4 g N m(-2) yr(-1). NH3 and gaseous HNO3, contributing about 80%, dominated the dry nitrogen deposition. Estimating the unmeasured nitrogen species by modeled values provides realistic approximations of total nitrogen deposition that also result in more realistic spatial patterns that could be used as input for further studies of likely nitrogen impacts on ecosystems.

  4. Variations of weekly atmospheric deposition for multiple collectors at a site on the shore of Lake Okeechobee, Florida

    Science.gov (United States)

    Peters, N.E.; Reese, R.S.

    1995-01-01

    Eight wet/dry precipitation collectors were modified to house four additional dryfall collectors and one bulk precipitation collector to sample atmospheric deposition for 12 weeks in a small area on the southwestern shore of Lake Okeechobee; sample contamination, primarily by insects, reduced the comparison to the last nine weeks. The deposition was determined for Ca2+, Na+, Cl-, and SO42- and nutrients including total phosphorus, orthophosphate, total ammonia plus organic nitrogen, and nitrite plus nitrate. In general, deposition was lower and less variable in wet precipitation than in bulk precipitation. The higher variability of the bulk precipitation was attributed to local contamination, particularly by dust and insects. Each wet/dry precipitation collector was fitted with dryfall collectors that consisted of the dry-side bucket on a wet/dry collector, which was preloaded with distilled and deionized water, and four glass dish collectors; two of the glass dishes were preloaded with water and the other two remained dry. The deposition to the dry dish collectors was not comparable in adjacent collectors for any constituent; however, the deposition in the adjacent water-loaded dishes was comparable for most major constituents, except nutrients. A comparison of Ortho-P deposition with Total-P indicated that the P collected by the dryfall collectors was predominantly reactive, which also was reflected in the bulk deposition, whereas that in the wet deposition was mostly nonreactive. The large variability in deposition of P among the bulk and dryfall collectors suggests that alternative methods must be used to evaluate the P sources and processes of atmospheric transfer.

  5. Hot dry rock geothermal energy

    Science.gov (United States)

    Heiken, G.; Murphy, H.; Nunz, G.; Potter, R.

    1981-08-01

    Man-made geothermal systems are discussed which make it possible to extract heat from hot rocks in areas where natural fluids are insufficient for the development of hydrothermal energy. The location and magnitude of high- and low-temperature geothermal resources in the USA for such hot dry rock (HDR) systems are examined. An HDR concept is described in which water is injected into one of two nearly parallel wells connected at depth by man-made fractures; the injected water circulates through the fracture system, where it is heated by conduction from the hot rock, and hot fluid, which can be used for heating or for electric power generation, rises through the second well. Some heat-extraction experiments using the described concept are reviewed which are being conducted in a complex volcanic field in New Mexico. The economics of HDR energy is evaluated.

  6. Thermoplastic dry polymer powder prepregging

    Energy Technology Data Exchange (ETDEWEB)

    Bucher, R.A.; Loos, A.C.; Meyer, G. [Virginia Polytechnic Institute and State Univ., Blacksburg, VA (United States)] [and others

    1995-12-01

    Thermoplastic resin systems have shown potential for reducing the manufacturing costs and improving the damage tolerance of composite structures. Current methods for thermoplastic resin impregnation of fiber bundles are limited by various difficulties and thus produce poor quality prepregs. The emerging technology of fiber is one of the most promising options, producing excellent matrix drape, and feasibility for a wide variety of matrix systems. An electrostatic dry polymer powder prepregging system was developed at the NSF Science and Technology Center at Virginia Tech, and has been used to produce high quality thermoplastic towpreg from a wide variety o polymer matrices. Additionally, a modification of the system allows for the production of towpreg from 15 gram polymer samples. This is ideal for the production of composites from resin systems under development, allowing early feedback concerning processing and composite mechanical performance.

  7. Dry fermentation of agricultural residues

    Science.gov (United States)

    Jewell, W. J.; Chandler, J. A.; Dellorto, S.; Fanfoni, K. J.; Fast, S.; Jackson, D.; Kabrick, R. M.

    1981-09-01

    A dry fermentation process is discussed which converts agricultural residues to methane, using the residues in their as produced state. The process appears to simplify and enhance the possibilities for using crop residues as an energy source. The major process variables investigated include temperature, the amount and type of inoculum, buffer requirements, compaction, and pretreatment to control the initial available organic components that create pH problems. A pilot-scale reactor operation on corn stover at a temperature of 550 C, with 25 percent initial total solids, a seed-to-feed ratio of 2.5 percent, and a buffer-to-feed ratio of 8 percent achieved 33 percent total volatile solids destruction in 60 days. Volumetric biogas yields from this unit were greater than 1 vol/vol day for 12 days, and greater than 0.5 vol/vol day for 32 days, at a substrate density of 169 kg/m (3).

  8. Will salt repositories be dry?

    Science.gov (United States)

    Bredehoeft, John D.

    The National Academy of Science committee that considered geologic disposal of nuclear waste in the mid-1950s recommended salt as a repository medium, partly because of its high thermal conductivity and because it was believed to be “dry” (perhaps the appropriate thought is “impermeable”). Certainly, the fact that Paleozoic salt deposits exist in many parts of t h e world is evidence for very low rates of dissolution by moving groundwater. The fact that the dissolution rates were so small led many scientists to the conclusion that the salt beds were nearly impermeable. The major source of brine within the salt beds was thought to be fluid inclusions within salt crystals, which could migrate through differential solution toward a source of high heat. The idea that salt was uniformly “dry” was revised when exploratory drilling in the vicinity of the Waste Isolation Pilot Plant (WIPP) in New Mexico encountered brines within the Castile Formation, an evaporite deposit below the Salado Formation. The brine reservoirs were thought to be isolated pockets of brine in an otherwise “impermeable” salt section.

  9. Setting up the drying regimes based on the theory of moisture migration during drying

    Science.gov (United States)

    Vasić, M.; Radojević, Z.

    2016-08-01

    Drying is energy intensive process which has important effect on the quality of the clay tiles that are dried commercially. Chamber and tunnel dryers are constantly improving. Better technical equipment and operational strategies have lead to higher quality of the dried clay products. The moisture migration during isothermal drying process can be visually traced on the curve that represents the relationship between variable effective moisture diffusivity (MR) with time (t). Proposed non isothermal drying regimes were consisted from several isothermal segments. For the first time, the choice of isothermal segments specification and its duration was not specified by experience or by trial-and-error method. It was detected from the isothermal curves Deff - MR in accordance with the theory of moisture migration during drying. Proposed drying regimes were tested. Clay roofing tiles were dried without cracks. Dried clay roofing tiles has satisfied all requirements defined in EN 1304 norm related to the shape regularity and mechanical properties.

  10. A statistical approach to optimize the spray drying of starch particles: application to dry powder coating.

    Science.gov (United States)

    Bilancetti, Luca; Poncelet, Denis; Loisel, Catherine; Mazzitelli, Stefania; Nastruzzi, Claudio

    2010-09-01

    This article describes the preparation of starch particles, by spray drying, for possible application to a dry powder coating process. Dry powder coating consists of spraying a fine powder and a plasticizer on particles. The efficiency of the coating is linked to the powder morphological and dimensional characteristics. Different experimental parameters of the spray-drying process were analyzed, including type of solvent, starch concentration, rate of polymer feeding, pressure of the atomizing air, drying air flow, and temperature of drying air. An optimization and screening of the experimental parameters by a design of the experiment (DOE) approach have been done. Finally, the produced spray-dried starch particles were conveniently tested in a dry coating process, in comparison to the commercial initial starch. The obtained results, in terms of coating efficiency, demonstrated that the spray-dried particles led to a sharp increase of coating efficiency value.

  11. The Urban Function of the Infraordinary: Dry Cleaners as Social Vertexes

    DEFF Research Database (Denmark)

    Lunde Nielsen, Espen

    2015-01-01

    of social coexistence that has ‘a function that is separate from their practical use’ (Jorn 1954). A London dry cleaner serves as testing ground, employing critical spatial practices and creative writing as research tools. The dry cleaner does not simply clean clothes, but is a social vertex and physical...... interface through which (non-)events unfold, trajectories thickens and people of the neighbourhood coexists as familiar strangers (Milgram 2010; Paulos and Goodman 2004) through events in real-time and deposits over time. It is a semi-public space and an implosion of the external neighbourhood, partly...

  12. CO2 (dry ice) cleaning system

    Science.gov (United States)

    Barnett, Donald M.

    1995-03-01

    Tomco Equipment Company has participated in the dry ice (solid carbon dioxide, CO2) cleaning industry for over ten years as a pioneer in the manufacturer of high density, dry ice cleaning pellet production equipment. For over four years Tomco high density pelletizers have been available to the dry ice cleaning industry. Approximately one year ago Tomco introduced the DI-250, a new dry ice blast unit making Tomco a single source supplier for sublimable media, particle blast, cleaning systems. This new blast unit is an all pneumatic, single discharge hose device. It meters the insertion of 1/8 inch diameter (or smaller), high density, dry ice pellets into a high pressure, propellant gas stream. The dry ice and propellant streams are controlled and mixed from the blast cabinet. From there the mixture is transported to the nozzle where the pellets are accelerated to an appropriate blasting velocity. When directed to impact upon a target area, these dry ice pellets have sufficient energy to effectively remove most surface coatings through dry, abrasive contact. The meta-stable, dry ice pellets used for CO2 cleaning, while labeled 'high density,' are less dense than alternate, abrasive, particle blast media. In addition, after contacting the target surface, they return to their equilibrium condition: a superheated gas state. Most currently used grit blasting media are silicon dioxide based, which possess a sharp tetrahedral molecular structure. Silicon dioxide crystal structures will always produce smaller sharp-edged replicas of the original crystal upon fracture. Larger, softer dry ice pellets do not share the same sharp-edged crystalline structures as their non-sublimable counterparts when broken. In fact, upon contact with the target surface, dry ice pellets will plastically deform and break apart. As such, dry ice cleaning is less harmful to sensitive substrates, workers and the environment than chemical or abrasive cleaning systems. Dry ice cleaning system

  13. Dry needling - peripheral and central considerations.

    Science.gov (United States)

    Dommerholt, Jan

    2011-11-01

    Dry needling is a common treatment technique in orthopedic manual physical therapy. Although various dry needling approaches exist, the more common and best supported approach targets myofascial trigger points. This article aims to place trigger point dry needling within the context of pain sciences. From a pain science perspective, trigger points are constant sources of peripheral nociceptive input leading to peripheral and central sensitization. Dry needling cannot only reverse some aspects of central sensitization, it reduces local and referred pain, improves range of motion and muscle activation pattern, and alters the chemical environment of trigger points. Trigger point dry needling should be based on a thorough understanding of the scientific background of trigger points, the differences and similarities between active and latent trigger points, motor adaptation, and central sensitize application. Several outcome studies are included, as well as comments on dry needling and acupuncture.

  14. Dry needling — peripheral and central considerations

    Science.gov (United States)

    Dommerholt, Jan

    2011-01-01

    Dry needling is a common treatment technique in orthopedic manual physical therapy. Although various dry needling approaches exist, the more common and best supported approach targets myofascial trigger points. This article aims to place trigger point dry needling within the context of pain sciences. From a pain science perspective, trigger points are constant sources of peripheral nociceptive input leading to peripheral and central sensitization. Dry needling cannot only reverse some aspects of central sensitization, it reduces local and referred pain, improves range of motion and muscle activation pattern, and alters the chemical environment of trigger points. Trigger point dry needling should be based on a thorough understanding of the scientific background of trigger points, the differences and similarities between active and latent trigger points, motor adaptation, and central sensitize application. Several outcome studies are included, as well as comments on dry needling and acupuncture. PMID:23115475

  15. Thin layer convection-drying of mushrooms

    Energy Technology Data Exchange (ETDEWEB)

    Pal, U.S.; Chakraverty, A. [Indian Inst. of Tech., Kharagpur (India). Dept. of Agricultural Engineering

    1997-06-01

    Dehydration characteristics of the Oyster Pleurotus variety of mushroom were studied. Both untreated and treated (steam blanching followed by sulphiting and citric acid pretreatment before drying) mushrooms were dried in the thin layer experimental equipment at each of the drying air temperatures of 45, 50 and 60{sup o}C with air velocities of 0.9 and 1.6 m/s. Studies on the equilibrium moisture content (EMC) of both untreated and treated dehydrated mushrooms were performed at different relative humidities ranging from 11.2 to 86.3% at 30{sup o}C. Taking drying time and quality of the dehydrated product into account, a combination of a drying air temperature of 50{sup o}C and an air velocity of 0.9 m/s appears to be suitable for drying of both untreated and treated mushrooms for a good dehydrated product. (author)

  16. Granitoid intrusions and related deposits

    Institute of Scientific and Technical Information of China (English)

    孟良义; 李绪俊

    1996-01-01

    Taking the Bainaimiao copper and gold deposits, Inner Mongolia and the Wushan copper deposits, Jiangxi Province as examples, a discussion is devoted to the relationship between the granitoid intrusions and related deposits from different lines of evidence: the spatial distribution, country rocks and alteration of the deposits, trace element contents and vertical zoning of elements in deposits, the metallogenic preference of granitoid intrusions, the metallogenic models and stable isotopic geology. It is concluded that the ore-bearing fluids mainly come from granitoid magmas and granitoid intrusions are closely associated with the related deposits in space.

  17. Developmental Tendency of Dry Land Farming Technologies

    Institute of Scientific and Technical Information of China (English)

    SHAN Lun

    2002-01-01

    The developmental tendency of dry land farming technologies in the semiarid area of China were reviewed based on the overview of recent progress in dry land farming researches from China and oversea. It was emphasized that conservation tillage, limited irrigation, genetic modification and chemical control are the important aspects for the dry land farming research and development of the future. In addition, some considerations and suggestions on above-mentioned aspects were proposed in this paper.

  18. Wood colour related to kiln drying

    OpenAIRE

    Sundqvist, Bror

    2000-01-01

    Raised temperature in artificial drying has led to some changes of wood products such as colour and strength etc. For special treatment of wood-products with clearly modified properties, among them colour, is often high temperature and steam used industrially. Knowledge about the colour rendering from wood that is subjected to heat under humid conditions and/or artificial drying, especially kiln drying, is thus of interest. It is also of interest to understand the chemical background, for the...

  19. Thin layer drying of tomato slices.

    Science.gov (United States)

    Das Purkayastha, Manashi; Nath, Amit; Deka, Bidyut Chandra; Mahanta, Charu Lata

    2013-08-01

    The hot air convective drying characteristics of blanched tomato (Lycopersicon esculantum L.) slices have been investigated. Drying experiments were carried out at four different temperatures (50, 60, 65 and 70 °C). The effect of drying temperatures on the drying behavior of the tomato slices was evaluated. All drying experiments had only falling rate period. The average effective diffusivity values varied from 0.5453 × 10(-9) to 2.3871 × 10(-9) m(2)/s over the temperature range studied and the activation energy was estimated to be 61.004 kJ/mol. In order to select a suitable form of the drying curve, six different thin layer drying models (Henderson-Pabis, Page, Diamante et al., Wang and Singh, Logarithmic and Newton models) were fitted to the experimental data. The goodness of fit tests indicated that the Logarithmic model gave the best fit to experimental results, which was closely followed by the Henderson-Pabis model. The influence of varied drying temperatures on quality attributes of the tomato slices viz. Hunter color parameters, ascorbic acid, lycopene, titratable acidity, total sugars, reducing sugars and sugar/acid ratio of dried slices was also studied. Slices dried at 50 and 60 °C had high amount of total sugars, lycopene, sugar/acid ratio, Hunter L- and a-values. Drying of slices at 50 °C revealed optimum retention of ascorbic acid, sugar/acid ratio and red hue, whereas, drying at higher temperature (65 and 70 °C) resulted in a considerable decrease in nutrients and colour quality of the slices.

  20. MODELLING OF THIN LAYER DRYING KINETICS OF COCOA BEANS DURING ARTIFICIAL AND NATURAL DRYING

    Directory of Open Access Journals (Sweden)

    C.L. HII

    2008-04-01

    Full Text Available Drying experiments were conducted using air-ventilated oven and sun dryer to simulate the artificial and natural drying processes of cocoa beans. The drying data were fitted with several published thin layer drying models. A new model was introduced which is a combination of the Page and two-term drying model. Selection of the best model was investigated by comparing the determination of coefficient (R2, reduced chi-square (2 and root mean square error (RMSE between the experimental and predicted values. The results showed that the new model was found best described the artificial and natural drying kinetics of cocoa under the conditions tested.

  1. High-efficiency filtration in dry/semi-dry FGD plants

    Energy Technology Data Exchange (ETDEWEB)

    Popovici, Florin [Evonik Fibres GmbH, Monza (Italy)

    2012-07-01

    Dry/semi-dry FGD plants are associated, in general, with a fabric filter plant. The paper highlights the importance of specific fibre properties like cross section and titre associated with the filtration requirements and the filter material chemical resistance for dry/semi-dry FGD process conditions in coal-fired boiler bag houses. References related to dry/semi-dry FGD plants applied to coal-fired boilers around the world are presented and include the performance evaluation of these plants, the type of filter media, plant design specifications, process parameters and particulate emission efficiency. (orig.)

  2. MODEL REPRESENTATION OF THE SPRAY DRYING PROCESS OF THE DISTILLERY STILLAGE FILTRATE BASED ON NAVIERSTOKES EQUATIONS

    Directory of Open Access Journals (Sweden)

    A. A. Shevtsov

    2015-01-01

    Full Text Available Spray drying of solutions and suspensions is among the most common methods of producing a wide range of powdered products in chemical, food and pharmaceutical industries. For the drying of heat-sensitive materials, which is fully applicable to the distillery stillage filtrate continuous-flow type of contact of drying agent and the solution droplets is examined. Two-phase simulation method of computational hydrodynamics in a stationary state for studying the process of drying of the distillery stillage filtrate in the pilot spray dryer under the following assumptions was used. The components form an ideal mixture, the properties of which are calculated directly from the properties of the components and their proportions. The droplets were presented in spherical form. The density and specific heat of the solution and the coefficient of vapors diffusion in the gas phase remained unchanged. To solve the heat exchange equations between the drying agent and the drops by the finite volume method the software package ANSYS CFX was used. The bind between the two phases was established by Navier-Stokes equations. The continuous phase (droplets of the distillery stillage filtrate was described by the k-ε turbulence model. The results obtained showed that the interaction of "drop-wall" causes a significant change of velocity, temperature and humidity both of a drying agent and the product particles. The behavior of the particles by spraying, collision with walls and deposition of the finished product allowed to determine the dependence of physical parameters of the drying process, of the geometric dimensions of the dryer. Comparison of simulation results with experimental data showed satisfactory convergence of the results: for the temperature of the powder 10% its humidity of 12% and temperature of the spent drying agent at the outlet from the drier of 13%. The possibility of using the model in the spray dryers designing, and control of the drying process

  3. 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.

  4. FINAL REPORT: Transformational electrode drying process

    Energy Technology Data Exchange (ETDEWEB)

    Claus Daniel, C.; Wixom, M.(A123 Systems, Inc.)

    2013-12-19

    This report includes major findings and outlook from the transformational electrode drying project performance period from January 6, 2012 to August 1, 2012. Electrode drying before cell assembly is an operational bottleneck in battery manufacturing due to long drying times and batch processing. Water taken up during shipment and other manufacturing steps needs to be removed before final battery assembly. Conventional vacuum ovens are limited in drying speed due to a temperature threshold needed to avoid damaging polymer components in the composite electrode. Roll to roll operation and alternative treatments can increase the water desorption and removal rate without overheating and damaging other components in the composite electrode, thus considerably reducing drying time and energy use. The objective of this project was the development of an electrode drying procedure, and the demonstration of processes with no decrease in battery performance. The benchmark for all drying data was an 80°C vacuum furnace treatment with a residence time of 18 – 22 hours. This report demonstrates an alternative roll to roll drying process with a 500-fold improvement in drying time down to 2 minutes and consumption of only 30% of the energy compared to vacuum furnace treatment.

  5. Cold vacuum drying facility design requirements

    Energy Technology Data Exchange (ETDEWEB)

    IRWIN, J.J.

    1999-07-01

    This document provides the detailed design requirements for the Spent Nuclear Fuel Project Cold Vacuum Drying Facility. Process, safety, and quality assurance requirements and interfaces are specified.

  6. Drying kinetics of some building materials

    Directory of Open Access Journals (Sweden)

    A. Moropoulou

    2005-06-01

    Full Text Available Moisture is one of the most deteriorating factors of buildings. The deteriorating effect of moisture occurs mainly during the drying phase, and not in the wetting phase. Appropriate parameters of the drying kinetics are required for the building materials. Environmental factors, such as air temperature, air humidity, and air velocity affect drying. An experimental air dryer of controlled drying air conditions was used to investigate the drying performance of 4 stone materials, 2 bricks and 7 plasters. Drying kinetics was examined at 4 air temperatures, 6 air humidities, and 3 air velocities. A first-order kinetics model was obtained, in which the drying time constant was a function of the drying conditions, and the equilibrium material moisture content was described by the Oswin equation. The parameters of the proposed model were found to be affected strongly by the material and the drying air conditions. The results obtained are very useful in selecting the appropriate plaster to protect existing historic buildings.

  7. Morphological Characteristics of Korean Dried Ginseng Products

    National Research Council Canada - National Science Library

    Hee-Do Hong; Chang-Woon Cho; Young-Chan Kim; Eunyoung Kim; Young-Kyung Rhee; Jeonghae Rho; Seung-Hoe Choi

    2012-01-01

    The purpose of this study was to determine a standard quality characteristic through the evaluation and statistical analysis of the morphological characteristics of dried ginseng (white ginseng) products...

  8. Liquid Crystal Research Shows Deformation By Drying

    Science.gov (United States)

    2003-01-01

    These images, from David Weitz's liquid crystal research, show ordered uniform sized droplets (upper left) before they are dried from their solution. After the droplets are dried (upper right), they are viewed with crossed polarizers that show the deformation caused by drying, a process that orients the bipolar structure of the liquid crystal within the droplets. When an electric field is applied to the dried droplets (lower left), and then increased (lower right), the liquid crystal within the droplets switches its alignment, thereby reducing the amount of light that can be scattered by the droplets when a beam is shone through them.

  9. Dry Mouth? Don't Delay Treatment

    Science.gov (United States)

    ... American Dental Association: Dry Mouth Related Consumer Updates Depression: FDA-Approved Medications May Help More in Consumer Updates Animal & Veterinary Children's Health Cosmetics Dietary Supplements Drugs Food ...

  10. Recent developments in drying of food products

    Science.gov (United States)

    Valarmathi, T. N.; Sekar, S.; Purushothaman, M.; Sekar, S. D.; Rama Sharath Reddy, Maddela; Reddy, Kancham Reddy Naveen Kumar

    2017-05-01

    Drying is a dehydration process to preserve agricultural products for long period usage. The most common and cheapest method is open sun drying in which the products are simply laid on ground, road, mats, roof, etc. But the open sun drying has some disadvantages like dependent on good weather, contamination by dust, birds and animals consume a considerable quantity, slow drying rate and damages due to strong winds and rain. To overcome these difficulties solar dryers are developed with closed environment for drying agricultural products effectively. To obtain good quality food with reduced energy consumption, selection of appropriate drying process and proper input parameters is essential. In recent years several researchers across the world have developed new drying systems for improving the product quality, increasing the drying rate, decreasing the energy consumption, etc. Some of the new systems are fluidized bed, vibrated fluidized bed, desiccant, microwave, vacuum, freeze, infrared, intermittent, electro hydrodynamic and hybrid dryers. In this review the most recent progress in the field of drying of agricultural food products such as new methods, new products and modeling and optimization techniques has been presented. Challenges and future directions are also highlighted. The review will be useful for new researchers entering into this ever needed and ever growing field of engineering.

  11. Antioxidant Properties of Some Dried Fruits

    Directory of Open Access Journals (Sweden)

    Bilge Ertekin Filiz

    2014-03-01

    Full Text Available In this study, total phenolic content and antioxidant capacity of various dried fruits were investigated. Total phenolic content of dried fruits (apple, quince, peach, orange, grapefruit, kiwi, banana, watermelon, cantaloupe, strawberries and tomatoes were between 219-5386 mg GAE/kg in dry matter (dm. TEAC and ORAC values of the samples were between 7.01-126 µmol TE/g dm and 11.69-211 µmol TE/g dm, respectively. Dried fruits can be considered as an important source of antioxidant components in diet with the higher antioxidant properties.

  12. Drying of Pigment-Cellulose Nanofibril Substrates

    Directory of Open Access Journals (Sweden)

    Oleg Timofeev

    2014-10-01

    Full Text Available A new substrate containing cellulose nanofibrils and inorganic pigment particles has been developed for printed electronics applications. The studied composite structure contains 80% fillers and is mechanically stable and flexible. Before drying, the solids content can be as low as 20% due to the high water binding capacity of the cellulose nanofibrils. We have studied several drying methods and their effects on the substrate properties. The aim is to achieve a tight, smooth surface keeping the drying efficiency simultaneously at a high level. The methods studied include: (1 drying on a hot metal surface; (2 air impingement drying; and (3 hot pressing. Somewhat surprisingly, drying rates measured for the pigment-cellulose nanofibril substrates were quite similar to those for the reference board sheets. Very high dewatering rates were observed for the hot pressing at high moisture contents. The drying method had significant effects on the final substrate properties, especially on short-range surface smoothness. The best smoothness was obtained with a combination of impingement and contact drying. The mechanical properties of the sheets were also affected by the drying method and associated temperature.

  13. Solar drying of uruguayan red gum

    Directory of Open Access Journals (Sweden)

    Andrés Ono

    2011-04-01

    Full Text Available he use of solar energy as an alternative to non-renewable energy sources has been widely researched in the last decades. Compared to air drying, solar drying kilns can better control the drying process, resulting in a higher quality of the dry wood and lower final wood moisture content values. Investment and running costs for a solar drying kiln are lower than those of a conventional kiln. Moreover, the solar drying process can be advantageous for drying hardwoods which are traditionally considered difficult to dry such as eucalyptus wood of medium and high density (Red gums, known in Spanish as “Eucaliptos colorados”. The solar drying kiln naturally incorporates a daily high relative humidity period that can be similar to a conditioning or steaming step, although at a lower temperature.This results in fewer defects due to the drying process.A pilot scale 2.5 m3 semi-greenhouse type solar wood drying kiln was constructed at LATU (Uruguay Technological Laboratory in Montevideo, Uruguay. The operating conditions and the results from two drying runs are presented. Two species of red gum (Eucalyptus tereticornis Sm., ADD 870 kg/m3, and Eucalyptus camaldulensis Dehnh., ADD 800 kg/m3 were dried from initial average moisture contents (WMC of around 60% down to 10.0% and 12.7% in 108 days and 76 days, respectively. Boards were provided by the Grupo Forestal San Gregorio from trees harvested at Tacuarembo and Paysandu Departments from cattle shelter forests 60 and 70 years old.Mean volume shrinkage was 18% for E. tereticornis, and 16% for E. camaldulensis, and the level of defects was moderate. Residual stresses and moisture content gradients were observed for both species. Final moisture content values were similar compared to those obtained in conventional drying kilns but with longer drying periods and lower operating costs. This would make the solar drying process attractive to small and medium sized forest products industries in a small country

  14. Evaluating the Age of Buried Ice in Antarctica Using Ashfall Deposits: New Insights from Deposit Morphology, Grain Shape, and LA-ICP-MS Trace-Element Geochemistry

    Science.gov (United States)

    Lewis, A. R.; Marchant, D. R.

    2003-12-01

    Dating of buried ice in the western Dry Valleys region relies on 40Ar/39Ar analysis of ashfall deposits within sublimation tills that rest directly on stagnant glacier ice. The oldest ice so dated is >8.1 Ma. The fundamental assumption is that dated ashes are in-situ and have not been transported from surface deposits elsewhere in the Dry Valleys region. Given that the surface of sublimation tills shows well-developed patterned ground, the presumption of ground stability and long-term preservation of in-situ ashfall is questioned. As a test of ground stability, we examined ash-deposit morphology, grain shape, and glass-shard trace-element geochemistry from several ashfall deposits used to provide limiting ages on buried ice and tills in the western Dry Valleys. Detailed field analyses show that ashfall that collects in sublimation tills over buried ice occurs in one of three morphologic settings: surface troughs that delineate sand-wedge polygons, void spaces in gravel-and-cobble lags that overlie active sand wedges, and 1 to 2-cm-wide thermal contraction cracks. Post-depositional sublimation of underlying ice may distort initial deposit morphology through uneven surface lowering. Microscopic analyses of concentrated ashfall deposits that lack detrital sand grains show highly angular glass shards that preserve delicate hair-like spires and thin bubble-wall vesicles. Grain edges are sharp with no chipped, fractured, or pitted surfaces. In contrast, ash deposits containing detrital sand grains show subangular to subrounded shard morphologies with concave fractures and pits on grain edges, all of which are suggestive of abrasion during transport. In such deposits, grains preserving delicate bubble walls and hair-like spires are conspicuously absent. Laser ablation-inductively coupled plasma-mass spectrometry shows that glass shards within each ashfall deposit have uniform trace-element geochemical signatures. If ashfall were eroded and transported after initial

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

    Directory of Open Access Journals (Sweden)

    J. Brandt

    2002-06-01

    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 deposition of 137Cs, 134Cs and 131I from the Chernobyl accident, using different relatively simple and comprehensive parameterizations. The performance, compared to measurements, of different combinations of parameterizations of wet and dry deposition schemes has been evaluated, using different statistical tests.

  16. 20 CFR 703.306 - Kinds of negotiable securities that may be deposited; conditions of deposit; acceptance of deposits.

    Science.gov (United States)

    2010-04-01

    ... the Act in the amount fixed by the Office under the regulations in this part shall deposit any... deposited; conditions of deposit; acceptance of deposits. 703.306 Section 703.306 Employees' Benefits... negotiable securities that may be deposited; conditions of deposit; acceptance of deposits. A self-insurer or...

  17. COMPARISON BETWEEN WOOD DRYING DEFECT SCORES: SPECIMEN TESTING X ANALYSIS OF KILN-DRIED BOARDS

    Directory of Open Access Journals (Sweden)

    Djeison Cesar Batista

    2015-04-01

    Full Text Available It is important to develop drying technologies for Eucalyptus grandis lumber, which is one of the most planted species of this genus in Brazil and plays an important role as raw material for the wood industry. The general aim of this work was to assess the conventional kiln drying of juvenile wood of three clones of Eucalyptus grandis. The specific aims were to compare the behavior between: i drying defects indicated by tests with wood specimens and conventional kiln-dried boards; and ii physical properties and the drying quality. Five 11-year-old trees of each clone were felled, and only flatsawn boards of the first log were used. Basic density and total shrinkage were determined, and the drying test with wood specimens at 100 °C was carried out. Kiln drying of boards was performed, and initial and final moisture content, moisture gradient in thickness, drying stresses and drying defects were assessed. The defect scoring method was used to verify the behavior between the defects detected by specimen testing and the defects detected in kiln-dried boards. As main results, the drying schedule was too severe for the wood, resulting in a high level of boards with defects. The behavior between the defects in the drying test with specimens and the defects of kiln-dried boards was different, there was no correspondence, according to the defect scoring method.

  18. Inkjet deposited circuit components

    Science.gov (United States)

    Bidoki, S. M.; Nouri, J.; Heidari, A. A.

    2010-05-01

    All-printed electronics as a means of achieving ultra-low-cost electronic circuits has attracted great interest in recent years. Inkjet printing is one of the most promising techniques by which the circuit components can be ultimately drawn (i.e. printed) onto the substrate in one step. Here, the inkjet printing technique was used to chemically deposit silver nanoparticles (10-200 nm) simply by ejection of silver nitrate and reducing solutions onto different substrates such as paper, PET plastic film and textile fabrics. The silver patterns were tested for their functionality to work as circuit components like conductor, resistor, capacitor and inductor. Different levels of conductivity were achieved simply by changing the printing sequence, inks ratio and concentration. The highest level of conductivity achieved by an office thermal inkjet printer (300 dpi) was 5.54 × 105 S m-1 on paper. Inkjet deposited capacitors could exhibit a capacitance of more than 1.5 nF (parallel plate 45 × 45 mm2) and induction coils displayed an inductance of around 400 µH (planar coil 10 cm in diameter). Comparison of electronic performance of inkjet deposited components to the performance of conventionally etched items makes the technique highly promising for fabricating different printed electronic devices.

  19. Aligned deposition and electrical measurements on single DNA molecules

    DEFF Research Database (Denmark)

    Eidelshtein, Gennady; Kotlyar, Alexander; Hashemi, Mohtadin

    2015-01-01

    bound to the surface, while the DNA counterpart interacts with the substrates much more weakly and can be lifted from the surface and realigned in any direction. Using this technique, avidin–DNA complexes were deposited across platinum electrodes on a silicon substrate. Electrical measurements......A reliable method of deposition of aligned individual dsDNA molecules on mica, silicon, and micro/nanofabricated circuits is presented. Complexes of biotinylated double stranded poly(dG)–poly(dC) DNA with avidin were prepared and deposited on mica and silicon surfaces in the absence of Mg2+ ions....... Due to its positive charge, the avidin attached to one end of the DNA anchors the complex to negatively charged substrates. Subsequent drying with a directional gas flow yields DNA molecules perfectly aligned on the surface. In the avidin–DNA complex only the avidin moiety is strongly and irreversibly...

  20. Deposition of YBCO Thin Film by Aerosol Assisted Spray Pyrolysis Method using Nitrate Precursors

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Byeong Joo; Hong, Seok Kwan; Lee, Jong Beom; Lee, Hee Gyoun; Hong, Gye Won [Korea Polytechnic University, Siheung (Korea, Republic of); Kim, Jae Geun [ISEM, University of Wollongong, Wollongong (Korea, Republic of)

    2010-10-15

    Y123 films have been deposited on (100) single-crystal and IBAD substrates by spray pyrolysis method using nitrate precursors. Ultrasonic atomization was adopted to decrease the droplet size, spraying angle and its moving velocity toward substrate for introducing the preheating tube furnace in appropriate location. A small preheating tube furnace was installed between spraying nozzle and substrate for fast drying and enhanced decomposition of precursors. C-axis oriented films were obtained on both LAO and IBAD substrates at deposition temperature of around and working pressures of 10-15 torr. Thick c-axis epitaxial film with the thickness of was obtained on LAO single-crystal by 10 min deposition. But the XRD results of the film deposited on IBAD template at same deposition condition showed that the buffer layers of the IBAD metal substrate was affected by long residence of metal substrate at high temperature for YBCO deposition.

  1. Atmospheric deposition of organic and black carbon to the global oceans

    Science.gov (United States)

    Jurado, Elena; Dachs, Jordi; Duarte, Carlos M.; Simó, Rafel

    Atmospheric deposition of total organic carbon (OC) and black carbon (BC) is lacking or not fully accounted in most current models of the global carbon cycling, specially those fluxes related to gas phase OC. Here, we develop and apply a methodology to estimate wet and dry deposition of total OC to the oceans, based on monthly satellite measurements of aerosol size distributions, wind speed, etc., and estimates of deposition for aerosols and organic compounds. The parameterization of dry deposition velocities account for the dependence of turbulent transport with aerosol diameter, wind speed and the formation of marine aerosol, etc. Gravitational settling is estimated as a function of wet particle diameter, thus including hygroscopic growth due to ambient humidity. Global dry deposition of aerosol OC is estimated to be 11 Tg C y -1 and wet deposition of particle and gaseous OC are estimated as 47 and 187 Tg C y -1, respectively. Due to their pulsing variability, wet deposition fluxes can be important locally and as a temporal source of OC to surface waters. Dry and wet deposition of black carbon to the global ocean are estimated to be 2 and 10 Tg C yr -1, respectively, with higher fluxes in the northern hemisphere and for inter-tropical regions. Finally, considerations on the potential magnitude of the hitherto neglected gross air-sea diffusive exchange fluxes of OC are discussed. Even though the magnitude and direction of these cannot be constrained here, evidence of its important role is given. This study, thus, shows that there is an important spatial and temporal variability in atmosphere-ocean exchanges of OC and BC at different scales, and calls for the need for further research on the important role that these exchanges play in the global carbon cycle.

  2. Rapid Ammonia Deposition Measured Near Concentrated Animal Feeding Operations

    Science.gov (United States)

    Stanton, L. G.; Pan, D.; Sun, K.; Golston, L.; Tao, L.; Zondlo, M. A.

    2014-12-01

    Concentrated animal feeding operations (CAFOs) emit massive amounts of ammonia (NH3) to the atmosphere. Current measurements of NH3 are generally conducted far away from the sources (satellites, airplanes, etc.). There is insufficient knowledge about the dry deposition rate of NH3 near the sources, which might contribute to the large discrepancies between measured concentrations at CAFOs and those from models. During the 2014 NASA DISCOVER-AQ campaign, we designed a series of tests to measure the deposition rate of NH3 by utilizing a suite of sensors, including a LICOR LI-7700 methane sensor and Princeton University's custom open path NH3 sensor, which was mounted on top of a small SUV. Our mobile sampling technique enables us to follow feedlot emission plumes to see how ambient NH3 concentration decays as gases moves away from the CAFO. The mobile platform is used to perform upwind and downwind sampling to characterize the NH3 emission source. We tracked the change of the enhancement of NH3 concentration relative to the enhancement of CH4 concentration (ΔNH3:ΔCH4), while transecting the plume of individual cattle feedlots. Measured data shows that the high concentration of NH3 seen at the source decreases quickly as one moves further downwind from it. A time constant of approximately ten minutes has been calculated from the decay of the ΔNH3:ΔCH4 ratios while moving away from the sources. We also will compare our measurements with those of NASA's P-3B aerosol measurements to show that the majority must be lost to dry deposition. This rapid deposition suggests that large amounts of NH3 are being deposited in very close proximity to these CAFOs, which is consistent with previous findings of locally high soil pH near NH3 sources. Our results will be used to better characterize nitrogen deposition from cattle feedlots and estimate NH3 lifetime.

  3. Cleaning properties of dry adhesives

    Institute of Scientific and Technical Information of China (English)

    J.; P.; DíAZ; TéLLEZ; D.; SAMEOTO; C.; MENON

    2010-01-01

    In this paper we present a study into the cleaning properties of synthetic dry adhesives. We have manufactured the adhesive micro-fibres through a low-cost, high yield fabrication method using Sylgard 184 Polydimethylsiloxane (PDMS) as the structural material. We deliberately contaminated the adhesive samples with different sized particles in the micro and macro scales and tested different cleaning methods for their efficacy with respect to each particle size. We investigated different cleaning methods, which included the use of wax moulding, vibration and pressure sensitive adhesives. For adhesion testing we used a custom system with a linear stage and a force sensor indenting a hemispherical probe into the adhesive surface and measuring the pull-off force. To characterize the cleaning efficacy we visually inspected each sample in a microscope and weighed the samples with a microgram-accuracy analytical balance. Results showed that the moulding method induced adhesion recovery in a greater percentage than the other cleaning methods and even helped with the recovery of collapsed posts in some cases. On the other hand pressure sensitive adhesives seem to have the upper hand with regards to certain particle sizes that can potentially pose problems with the moulding method.

  4. Market Discipline and Deposit Insurance

    OpenAIRE

    Peresetsky,Anatoly

    2008-01-01

    The paper examines Russian banks’ household deposit interest rates for the transition period of setting up the deposit insurance system. Monthly observations of Russian banks’ interest rates and balance sheets are used in a fixed effects panel data model. It is shown market discipline has been significantly diminished after switching to the deposit insurance.

  5. The investigation of atmospheric deposition distribution of organochlorine pesticides (OCPs) in Turkey

    Science.gov (United States)

    Cindoruk, S. Sıddık; Tasdemir, Yücel

    2014-04-01

    Atmospheric deposition is a significant pollution source leading to contamination of remote and clean sites, surface waters and soils. Since persistent organic pollutants (POPs) stay in atmosphere without any degradation, they can be transported and deposited to clean surfaces. Organochlorine pesticides are an important group of POPs which have toxic and harmful effects to living organisms and environment. Therefore, atmospheric deposition levels and characteristics are of importance to determine the pollution quantity of water and soil surfaces in terms of POPs. This study reports the distribution quantities of atmospheric deposition including bulk, dry, wet and air-water exchange of particle and gas phase OCPs as a result of 1-year sampling campaign. Atmospheric deposition distribution showed that the main mechanism for OCPs deposition is wet processes with percentage of 69 of total deposition. OCP compounds' deposition varied according to atmospheric concentration and deposition mechanism. HCH compounds were dominant pesticide species for all deposition mechanisms. HCH deposition constituted the 65% of Σ10OCPs.

  6. Spray drying technique. I: Hardware and process parameters.

    Science.gov (United States)

    Cal, Krzysztof; Sollohub, Krzysztof

    2010-02-01

    Spray drying is a transformation of feed from a fluid state into a dried particulate form by spraying the feed into a hot drying medium. The main aim of drying by this method in pharmaceutical technology is to obtain dry particles with desired properties. This review presents the hardware and process parameters that affect the properties of the dried product. The atomization devices, drying chambers, air-droplet contact systems, the collection of dried product, auxiliary devices, the conduct of the spray drying process, and the significance of the individual parameters in the drying process, as well as the obtained product, are described and discussed.

  7. 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

  8. Investigation of Solar Drying of Ginger (Zingiber officinale): Emprical Modelling, Drying Characteristics, and Quality Study

    OpenAIRE

    A. Waheed Deshmukh; Mahesh N. Varma; Chang Kyoo Yoo; Wasewar, Kailas L.

    2014-01-01

    Drying is a simultaneous heat and mass transfer energy intensive operation, widely used as a food preservation technique. In view of improper postharvest methods, energy constraint, and environmental impact of conventional drying methods, solar drying could be a practical, economical, and environmentally reliable alternative. In the present paper applicability of mixed mode solar cabinet dryer was investigated for drying of commercially important and export oriented ginger. Freshly harvested ...

  9. Cold vacuum drying facility 90% design review

    Energy Technology Data Exchange (ETDEWEB)

    O`Neill, C.T.

    1997-05-02

    This document contains review comment records for the CVDF 90% design review. Spent fuels retrieved from the K Basins will be dried at the CVDF. It has also been recommended that the Multi-Conister Overpacks be welded, inspected, and repaired at the CVD Facility before transport to dry storage.

  10. Control of fluidized bed tea drying

    NARCIS (Netherlands)

    Temple, S.J.

    2000-01-01

    Tea is a product made from the leaf of the tea bush by several processes, including drying. The drying stage is the most energy intensive, and has tight performance criteria. This project investigated the options for the control of a fluidized bed tea dryer. The work included establishing some of th

  11. Dry phase reactor for generating medical isotopes

    Science.gov (United States)

    Mackie, Thomas Rockwell; Heltemes, Thad Alexander

    2016-05-03

    An apparatus for generating medical isotopes provides for the irradiation of dry-phase, granular uranium compounds which are then dissolved in a solvent for separation of the medical isotope from the irradiated compound. Once the medical isotope is removed, the dissolved compound may be reconstituted in dry granular form for repeated irradiation.

  12. Hot-dry-rock feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    1981-08-01

    The hot-dry-rock project tasks are covered as follows: hot-dry-rock reservoir; generation facilities; water resources; transmission requirements; environmental issues; government and community institutional factors; leasing, ownership and management of facilities; regulations, permits, and laws; and financial considerations. (MHR)

  13. Reflectance characteristics of dry plant materials

    Science.gov (United States)

    Elvidge, Christopher D.

    1987-01-01

    Chlorophyll and water obscure the absorption features of all other leaf constituents in the spectra of green leaves. The predominant near-IR and thermal IR spectral features of dry plant materials originate from lignin, cellulose, and hemicellulose. These compounds account for 80 to 98 percent of the dry weight in most plant materials.

  14. 7 CFR 58.220 - Drying systems.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Drying systems. 58.220 Section 58.220 Agriculture....220 Drying systems. (a) Spray dryers. Spray dryers shall be of a continuous discharge type and all... filter system shall comply with the applicable requirements of the 3-A Accepted Practices for Milk and...

  15. 27 CFR 24.202 - Dried fruit.

    Science.gov (United States)

    2010-04-01

    ... reduce the density to 22 degrees Brix. If the dried fruit liquid after restoration is found to be... degrees Brix. After addition of water to the dried fruit, the resulting liquid may be ameliorated with... Brix. (26 U.S.C. 5387)...

  16. Application of Dry Air Drying Techniques on West-East Gas Pipeline Project

    Institute of Scientific and Technical Information of China (English)

    GaoJianguo; XieLigong; DaiZongyu

    2004-01-01

    Based on the pre-eommissioning requirements of gas pipeline, the basic principles and influential factors of dry air drying adopted in long distance gas pipelines, and states in detail the technological flow and the equipment required, etc. are introduced, which will have practical significance in drying operation on gas pipeline.

  17. Desorption isotherms, drying characteristics and qualities of glace tropical fruits undergoing forced convection solar drying

    Energy Technology Data Exchange (ETDEWEB)

    Jamradloedluk, Jindaporn; Wiriyaumpaiwong, Songchai [Mahasarakham Univ. Khamriang, Kantarawichai, Mahasarakham (Thailand)

    2008-07-01

    Solar energy, a form of sustainable energy, has a great potential for a wide variety of applications because it is abundant and accessible, especially for countries located in the tropical region. Drying process is one of the prominent techniques for utilization of solar energy. This research work proposes a forced convection solar drying of osmotically pretreated fruits viz. mango, guava, and pineapple. The fruit cubes with a dimension of 1cm x 1cm x 1cm were immersed in 35% w./w. sucrose solution prior to the drying process. Drying kinetics, color and hardness of the final products obtained from solar drying were investigated and compared with those obtained from open air-sun drying. Desorption isotherms of the osmosed fruits were also examined and five mathematical models were used to fit the desorption curves. Experimental results revealed that solar drying provided higher drying rate than natural sun drying. Color of glace fruit processed by solar drying was more intense, indicated by lower value of lightness and higher value of yellowness, than that processed by sun drying. Hardness of the products dehydrated by both drying methods, however, was not significantly different (p>0.05). Validation of the mathematical models developed showed that the GAB model was most effective for describing desorption isotherms of osmotically pretreated mango and pineapple whereas Peleg's model was most effective for describing desorption isotherms of osmotically pretreated guava. (orig.)

  18. Optimization of a solar-assisted drying system for drying bananas

    Energy Technology Data Exchange (ETDEWEB)

    Smitabhindu, R. [Department of Industrial Engineering, Kasetsart University, Bangkok 10900 (Thailand); Janjai, S. [Department of Physics, Faculty of Science, Silpakorn University, Nakhon Pathom 73000 (Thailand); Chankong, V. [Department of Electrical Engineering and Computer Science, Case Western Reserve University, Cleveland, OH (United States)

    2008-07-15

    This paper presents a mathematical model for optimal design of a solar-assisted drying system for drying bananas. The optimization model consists of a simulation model of a solar-assisted drying system combined with an economic model. The simulation model is composed of two systems of differential equations: one for the collector and other for the drying cabinet. These systems of the differential equation were solved using the finite difference method. Values of the model parameters were determined experimentally. A computer program in FORTRAN was developed to simulate the performance of the drying system. The model was validated by comparing the simulation results with the experimental results and they were in good agreement. This simulation model was used for the optimization of the solar-assisted drying system. An economic model was formulated to calculate the annual drying cost. The optimization problem was defined as the optimization of the geometry and operational parameters of the drying system so as to minimize the drying cost per unit of dried product. Currently used collector area and the air recycle factor were considered as the parameters for basic mode of operation of the drying system. The adaptive pattern search technique was adopted to find the optimum values of the solar collector area and the recycle factor. The optimum values of the collector area and the recycle factor were found to be 26 m{sup 2} and 90%, respectively. The computer program developed in this study can be used to optimize similar drying systems. (author)

  19. Drying kinetics and quality aspects during heat pump drying of onion (Allium cepa L.

    Directory of Open Access Journals (Sweden)

    Nihar Ranjan Sahoo

    2012-10-01

    Full Text Available Normal 0 false false false MicrosoftInternetExplorer4 A prototype heat pump dryer has been developed for drying of fruits and vegetables at low temperature and relative humidity to maintain the quality of dried product. Onions, of Nasik red variety were peeled, trimmed and sliced to 2 mm thickness. The onion slices were dried in the heat pump dryer at 35ºC (32 % R.H., 40ºC (26 % R.H., 45ºC (19 % R.H. and 50ºC (15 % R.H.. Samples were also dried in a hot air dryer at 50ºC (52 % R.H. for comparison. The drying rate increased with increase in drying air temperature, associated with reduced R.H., in the heat pump dryer. Drying took place mainly under the falling rate period. The Page equation, resulting in a higher coefficient of determination and lower root mean square error, better described the thin-layer drying of onion slices than the Henderson and Pabis equation. Heat pump drying took less drying time of 360 min and yielded better quality dried product, with higher retention of ascorbic acid and pyruvic acid and lower colour change, as compared to a hot air dryer at the same drying air temperature of 50ºC.

  20. Investigation of effects of varying model inputs on mercury deposition estimates in the Southwest US

    Directory of Open Access Journals (Sweden)

    T. Myers

    2012-04-01

    Full Text Available The Community Multiscale Air Quality (CMAQ model version 4.7.1 was used to simulate mercury wet and dry deposition for a domain covering the contiguous United States (US. The simulations used MM5-derived meteorological input fields and the US Environmental Protection Agency (EPA Clear Air Mercury Rule (CAMR emissions inventory. Using sensitivity simulations with different boundary conditions and tracer simulations, this investigation focuses on the contributions of boundary concentrations to deposited mercury in the Southwest (SW US. Concentrations of oxidized mercury species along the boundaries of the domain, in particular the upper layers of the domain, can make significant contributions to the simulated wet and dry deposition of mercury in the SW US. In order to better understand the contributions of boundary conditions to deposition, inert tracer simulations were conducted to quantify the relative amount of an atmospheric constituent transported across the boundaries of the domain at various altitudes and to quantify the amount that reaches and potentially deposits to the land surface in the SW US. Simulations using alternate sets of boundary concentrations, including estimates from global models (Goddard Earth Observing System-Chem (GEOS-Chem and the Global/Regional Atmospheric Heavy Metals (GRAHM model, and alternate meteorological input fields (for different years are analyzed in this paper. CMAQ dry deposition in the SW US is sensitive to differences in the atmospheric dynamics and atmospheric mercury chemistry parameterizations between the global models used for boundary conditions.