WorldWideScience

Sample records for models deposition studies

  1. NURE uranium deposit model studies

    International Nuclear Information System (INIS)

    Crew, M.E.

    1981-01-01

    The National Uranium Resource Evaluation (NURE) Program has sponsored uranium deposit model studies by Bendix Field Engineering Corporation (Bendix), the US Geological Survey (USGS), and numerous subcontractors. This paper deals only with models from the following six reports prepared by Samuel S. Adams and Associates: GJBX-1(81) - Geology and Recognition Criteria for Roll-Type Uranium Deposits in Continental Sandstones; GJBX-2(81) - Geology and Recognition Criteria for Uraniferous Humate Deposits, Grants Uranium Region, New Mexico; GJBX-3(81) - Geology and Recognition Criteria for Uranium Deposits of the Quartz-Pebble Conglomerate Type; GJBX-4(81) - Geology and Recognition Criteria for Sandstone Uranium Deposits in Mixed Fluvial-Shallow Marine Sedimentary Sequences, South Texas; GJBX-5(81) - Geology and Recognition Criteria for Veinlike Uranium Deposits of the Lower to Middle Proterozoic Unconformity and Strata-Related Types; GJBX-6(81) - Geology and Recognition Criteria for Sandstone Uranium Deposits of the Salt Wash Type, Colorado Plateau Province. A unique feature of these models is the development of recognition criteria in a systematic fashion, with a method for quantifying the various items. The recognition-criteria networks are used in this paper to illustrate the various types of deposits

  2. Model boiler studies on deposition and corrosion

    International Nuclear Information System (INIS)

    Balakrishnan, P.V.; McVey, E.G.

    1977-09-01

    Deposit formation was studied in a model boiler, with sea-water injections to simulate the in-leakage which could occur from sea-water cooled condensers. When All Volatile Treatment (AVT) was used for chemistry control the deposits consisted of the sea-water salts and corrosion products. With sodium phosphate added to the boiler water, the deposits also contained the phosphates derived from the sea-water salts. The deposits were formed in layers of differing compositions. There was no significant corrosion of the Fe-Ni-Cr alloy boiler tube under deposits, either on the open area of the tube or in crevices. However, carbon steel that formed a crevice around the tube was corroded severely when the boiler water did not contain phosphate. The observed corrosion of carbon steel was caused by the presence of acidic, highly concentrated chloride solution produced from the sea-water within the crevice. Results of theoretical calculations of the composition of the concentrated solution are presented. (author)

  3. Experimental Study of Aerosol Deposition in a Realistic Lung Model

    Directory of Open Access Journals (Sweden)

    František LÍZAL

    2010-12-01

    Full Text Available The inhalation route for administration of medicaments is becoming more and more popular in recent years. The reason is non-invasiveness of the method and instantaneous absorption of drugs to the blood circulation. It is necessary to deliver exact amount of drug to the specific segment because of occurrence of diverse diseases in different segments of lungs. The aim of our work is to contribute to better understanding of transport and deposition of aerosolized drugs in lungs and hence to more effective treatment of respiratory diseases due to the targeted drug delivery. We provided measurements of aerosol deposition in segmented realistic model of lungs without a mouth cavity. Monodisperse particles marked with fluorescein were supplied to the model. The model was then disassembled to segments and each segment was rinsed with isopropanol, whereby fluorescent samples were created. Each sample was analysed by fluorometer and an amount of aerosol deposited in the segment was calculated. Experiences obtained by this study were used for creation of a new model with the mouth cavity. This model will be used for future studies with porous and fiber aerosols.

  4. Stratiform chromite deposit model

    Science.gov (United States)

    Schulte, Ruth F.; Taylor, Ryan D.; Piatak, Nadine M.; Seal, Robert R.

    2010-01-01

    Stratiform chromite deposits are of great economic importance, yet their origin and evolution remain highly debated. Layered igneous intrusions such as the Bushveld, Great Dyke, Kemi, and Stillwater Complexes, provide opportunities for studying magmatic differentiation processes and assimilation within the crust, as well as related ore-deposit formation. Chromite-rich seams within layered intrusions host the majority of the world's chromium reserves and may contain significant platinum-group-element (PGE) mineralization. This model of stratiform chromite deposits is part of an effort by the U.S. Geological Survey's Mineral Resources Program to update existing models and develop new descriptive mineral deposit models to supplement previously published models for use in mineral-resource and mineral-environmental assessments. The model focuses on features that may be common to all stratiform chromite deposits as a way to gain insight into the processes that gave rise to their emplacement and to the significant economic resources contained in them.

  5. Modeling study of deposition locations in the 291-Z plenum

    International Nuclear Information System (INIS)

    Mahoney, L.A.; Glissmeyer, J.A.

    1994-06-01

    The TEMPEST (Trent and Eyler 1991) and PART5 computer codes were used to predict the probable locations of particle deposition in the suction-side plenum of the 291-Z building in the 200 Area of the Hanford Site, the exhaust fan building for the 234-5Z, 236-Z, and 232-Z buildings in the 200 Area of the Hanford Site. The Tempest code provided velocity fields for the airflow through the plenum. These velocity fields were then used with TEMPEST to provide modeling of near-floor particle concentrations without particle sticking (100% resuspension). The same velocity fields were also used with PART5 to provide modeling of particle deposition with sticking (0% resuspension). Some of the parameters whose importance was tested were particle size, point of injection and exhaust fan configuration

  6. Atmospheric Deposition Modeling Results

    Data.gov (United States)

    U.S. Environmental Protection Agency — This asset provides data on model results for dry and total deposition of sulfur, nitrogen and base cation species. Components include deposition velocities, dry...

  7. Sulfur deposition simulations over China, Japan, and Korea: a model intercomparison study for abating sulfur emission.

    Science.gov (United States)

    Kim, Cheol-Hee; Chang, Lim-Seok; Meng, Fan; Kajino, Mizuo; Ueda, Hiromasa; Zhang, Yuanhang; Son, Hye-Young; Lee, Jong-Jae; He, Youjiang; Xu, Jun; Sato, Keiichi; Sakurai, Tatsuya; Han, Zhiwei; Duan, Lei; Kim, Jeong-Soo; Lee, Suk-Jo; Song, Chang-Keun; Ban, Soo-Jin; Shim, Shang-Gyoo; Sunwoo, Young; Lee, Tae-Young

    2012-11-01

    In response to increasing trends in sulfur deposition in Northeast Asia, three countries in the region (China, Japan, and Korea) agreed to devise abatement strategies. The concepts of critical loads and source-receptor (S-R) relationships provide guidance for formulating such strategies. Based on the Long-range Transboundary Air Pollutants in Northeast Asia (LTP) project, this study analyzes sulfur deposition data in order to optimize acidic loads over the three countries. The three groups involved in this study carried out a full year (2002) of sulfur deposition modeling over the geographic region spanning the three countries, using three air quality models: MM5-CMAQ, MM5-RAQM, and RAMS-CADM, employed by Chinese, Japanese, and Korean modeling groups, respectively. Each model employed its own meteorological numerical model and model parameters. Only the emission rates for SO(2) and NO(x) obtained from the LTP project were the common parameter used in the three models. Three models revealed some bias from dry to wet deposition, particularly the latter because of the bias in annual precipitation. This finding points to the need for further sensitivity tests of the wet removal rates in association with underlying cloud-precipitation physics and parameterizations. Despite this bias, the annual total (dry plus wet) sulfur deposition predicted by the models were surprisingly very similar. The ensemble average annual total deposition was 7,203.6 ± 370 kt S with a minimal mean fractional error (MFE) of 8.95 ± 5.24 % and a pattern correlation (PC) of 0.89-0.93 between the models. This exercise revealed that despite rather poor error scores in comparison with observations, these consistent total deposition values across the three models, based on LTP group's input data assumptions, suggest a plausible S-R relationship that can be applied to the next task of designing cost-effective emission abatement strategies.

  8. Development of a Zealand white rabbit deposition model to study inhalation anthrax

    Energy Technology Data Exchange (ETDEWEB)

    Asgharian, Bahman; Price, Owen; Kabilan, Senthil; Jacob, Richard E.; Einstein, Daniel R.; Kuprat, Andrew P.; Corley, Richard A.

    2016-01-28

    Despite using rabbits in several inhalation exposure experiments to study diseases such as anthrax, there is a lack of understanding regarding deposition characteristics and fate of inhaled particles (bio-aerosols and viruses) in the respiratory tracts of rabbits. Such information allows dosimetric extrapolation to humans to inform human outcomes. The lung geometry of the New Zealand white rabbit (referred to simply as rabbits throughout the article) was constructed using recently acquired scanned images of the conducting airways of rabbits and available information on its acinar region. In addition, functional relationships were developed for the lung and breathing parameters of rabbits as a function of body weight. The lung geometry and breathing parameters were used to extend the existing deposition model for humans and several other species to rabbits. Evaluation of the deposition model for rabbits was made by comparing predictions with available measurements in the literature. Deposition predictions in the lungs of rabbits indicated smaller deposition fractions compared to those found in humans across various particle diameter ranges. The application of the deposition model for rabbits was demonstrated by extrapolating deposition predictions in rabbits to find equivalent human exposure concentrations assuming the same dose-response relationship between the two species. Human equivalent exposure concentration levels were found to be much smaller than those for rabbits.

  9. 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...

  10. Solution processed deposition of electron transport layers on perovskite crystal surface—A modeling based study

    Energy Technology Data Exchange (ETDEWEB)

    Mortuza, S.M.; Taufique, M.F.N.; Banerjee, Soumik, E-mail: soumik.banerjee@wsu.edu

    2017-02-01

    Highlights: • The model determined the surface coverage of solution-processed film on perovskite. • Calculated surface density map provides insight into morphology of the monolayer. • Carbonyl oxygen atom of PCBM strongly attaches to the (110) surface of perovskite. • Uniform distribution of clusters on perovskite surface at lower PCBM concentration. • Deposition rate of PCBM on the surface is very high at initial stage of film growth. - Abstract: The power conversion efficiency (PCE) of planar perovskite solar cells (PSCs) has reached up to ∼20%. However, structural and chemicals defects that lead to hysteresis in the perovskite based thin film pose challenges. Recent work has shown that thin films of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) deposited on the photo absorption layer, using solution processing techniques, minimize surface pin holes and defects thereby increasing the PCE. We developed and employed a multiscale model based on molecular dynamics (MD) and kinetic Monte Carlo (kMC) to establish a relationship between deposition rate and surface coverage on perovskite surface. The MD simulations of PCBMs dispersed in chlorobenzene, sandwiched between (110) perovskite substrates, indicate that PCBMs are deposited through anchoring of the oxygen atom of carbonyl group to the exposed lead (Pb) atom of (110) perovskite surface. Based on rates of distinct deposition events calculated from MD, kMC simulations were run to determine surface coverage at much larger time and length scales than accessible by MD alone. Based on the model, a generic relationship is established between deposition rate of PCBMs and surface coverage on perovskite crystal. The study also provides detailed insights into the morphology of the deposited film.

  11. Solution processed deposition of electron transport layers on perovskite crystal surface—A modeling based study

    International Nuclear Information System (INIS)

    Mortuza, S.M.; Taufique, M.F.N.; Banerjee, Soumik

    2017-01-01

    Highlights: • The model determined the surface coverage of solution-processed film on perovskite. • Calculated surface density map provides insight into morphology of the monolayer. • Carbonyl oxygen atom of PCBM strongly attaches to the (110) surface of perovskite. • Uniform distribution of clusters on perovskite surface at lower PCBM concentration. • Deposition rate of PCBM on the surface is very high at initial stage of film growth. - Abstract: The power conversion efficiency (PCE) of planar perovskite solar cells (PSCs) has reached up to ∼20%. However, structural and chemicals defects that lead to hysteresis in the perovskite based thin film pose challenges. Recent work has shown that thin films of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) deposited on the photo absorption layer, using solution processing techniques, minimize surface pin holes and defects thereby increasing the PCE. We developed and employed a multiscale model based on molecular dynamics (MD) and kinetic Monte Carlo (kMC) to establish a relationship between deposition rate and surface coverage on perovskite surface. The MD simulations of PCBMs dispersed in chlorobenzene, sandwiched between (110) perovskite substrates, indicate that PCBMs are deposited through anchoring of the oxygen atom of carbonyl group to the exposed lead (Pb) atom of (110) perovskite surface. Based on rates of distinct deposition events calculated from MD, kMC simulations were run to determine surface coverage at much larger time and length scales than accessible by MD alone. Based on the model, a generic relationship is established between deposition rate of PCBMs and surface coverage on perovskite crystal. The study also provides detailed insights into the morphology of the deposited film.

  12. Modeling of asphaltene particle deposition from turbulent oil flow in tubing: Model validation and a parametric study

    Directory of Open Access Journals (Sweden)

    Peyman Kor

    2016-12-01

    Full Text Available The deposition of asphaltenes on the inner wall of oil wells and pipelines causes flow blockage and significant production loss in these conduits. The major underlying mechanism(s for the deposition of asphaltene particles from the oil stream are still under investigation as an active research topic in the literature. In this work, a new deposition model considering both diffusional and inertial transport of asphaltene toward the tubing surface was developed. Model predictions were compared and verified with two sound experimental data available in the literature to evaluate the model's performance. A parametric study was done using the validated model in order to investigate the effect of the asphaltene particle size, flow velocity and oil viscosity on the magnitude of asphaltene deposition rate. Results of the study revealed that increasing the oil velocity causes more drag force on wall's inner surface; consequently, particles tend to transport away from the surface and the rate of asphaltene deposition is decreased. In addition, the developed model predicts that at low fluid velocity (∼0.7 m/s, the less viscous oil is more prone to asphaltene deposition problem.

  13. Experimental Study and Mathematical Modeling of Asphaltene Deposition Mechanism in Core Samples

    Directory of Open Access Journals (Sweden)

    Jafari Behbahani T.

    2015-11-01

    Full Text Available In this work, experimental studies were conducted to determine the effect of asphaltene deposition on the permeability reduction and porosity reduction of carbonate, sandstone and dolomite rock samples using an Iranian bottom hole live oil sample which is close to reservoir conditions, whereas in the majority of previous work, a mixture of recombined oil (a mixture of dead oil and associated gas was injected into a core sample which is far from reservoir conditions. The effect of the oil injection rate on asphaltene deposition and permeability reduction was studied. The experimental results showed that an increase in the oil injection flow rate can result in an increase in asphaltene deposition and permeability reduction. Also, it can be observed that at lower injection flow rates, a monotonic decrease in permeability of the rock samples can be attained upon increasing the injection flow rate, while at higher injection rates, after a decrease in rock permeability, an increasing trend is observed before a steady-state condition can be reached. The experimental results also showed that the rock type can affect the amount of asphaltene deposition, and the asphaltene deposition has different mechanisms in sandstone and carbonate core samples. It can be seen that the adsorption and plugging mechanisms have a more important role in asphaltene deposition in carbonate core samples than sandstone core samples. From the results, it can be observed that the pore volumes of the injected crude oil are higher for sandstone cores compared with the carbonate cores. Also, it can be inferred that three depositional types may take place during the crude oil injection, i.e., continuous deposition for low-permeability cores, slow, steady plugging for high-permeability cores and steady deposition for medium-permeability cores. It can be seen from the experimental results that damage to the core samples was found to increase when the production pressures were

  14. Impacts of climate and emission changes on nitrogen deposition in Europe: a multi-model study

    Directory of Open Access Journals (Sweden)

    D. Simpson

    2014-07-01

    Full Text Available The impact of climate and emissions changes on the deposition of reactive nitrogen (Nr over Europe was studied using four offline regional chemistry transport models (CTMs driven by the same global projection of future climate over the period 2000–2050. Anthropogenic emissions for the years 2005 and 2050 were used for simulations of both present and future periods in order to isolate the impact of climate change, hemispheric boundary conditions and emissions, and to assess the robustness of the results across the different models. The results from these four CTMs clearly show that the main driver of future N-deposition changes is the specified emission change. Under the specified emission scenario for 2050, emissions of oxidised nitrogen were reduced substantially, whereas emissions of NH3 increase to some extent, and these changes are largely reflected in the modelled concentrations and depositions. The lack of sulfur and oxidised nitrogen in the future atmosphere results in a much larger fraction of NHx being present in the form of gaseous ammonia. Predictions for wet and total deposition were broadly consistent, although the three fine-scale models resolve European emission areas and changes better than the hemispheric-scale model. The biggest difference in the models is for predictions of individual N compounds. One model (EMEP was used to explore changes in critical loads, also in conjunction with speculative climate-induced increases in NH3 emissions. These calculations suggest that the area of ecosystems that exceeds critical loads is reduced from 64% for year 2005 emissions levels to 50% for currently estimated 2050 levels. A possible climate-induced increase in NH3 emissions could worsen the situation, with areas exceeded increasing again to 57% (for a 30% NH3 emission increase.

  15. A generic Froude scale model study of massive bedload deposition in a debris basin

    Science.gov (United States)

    Piton, Guillaume; Recking, Alain

    2017-04-01

    Sediment trapping structures, such as gravel deposition basins, are regularly implemented in mountainous context for flood hazard mitigation. These structures should ultimately trap gravels when their excess may aggravate the downstream flood hazard, while, the remaining time, allowing a suitable background sediment continuity. Such optimized designs require a sufficient knowledge of the flow features and geomorphic processes implied in gravel trapping. A generic Froude scale model of a 10%-steep, bedload deposition basin, with a slit dam and without outlet structure, is presented in this work. Accurate photogrammetry and large scale particle image velocimetry (LS-PIV) were combined to study the geomorphic patterns and to reconstruct the flows. The emergence of self induced cycles of braided and channelized flows, with intense grain size sorting, is described. It sheds light on the similarity of bedload trapping with alluvial fan formation or fluvial delta development. The deposition slope, a key parameter in the structure design, is more precisely studied. The measurements are correctly estimated by a new simple equation, which is developed from prior works dedicated to steep slope stream hydraulics and bedload transport. The analysis demonstrates additionally that, despite the steepness of the studied conditions, most flows are subcritical due to roughness adjustment. We finally highlight that morphologically-active flows, i.e., with dimensionless shear stress higher than the threshold for motion, have Froude number ≈ 1; i.e., that a critical flow hypothesis seems reasonable, as a first approximation, to describe flows over massive bedload depositions. This new dataset, with complete geomorphic and flow measurements, in diverse conditions, may be used as reference to try and test numerical approaches of the phenomena.

  16. Study on particle deposition in vertical square ventilation duct flows by different models

    International Nuclear Information System (INIS)

    Zhang Jinping; Li Angui

    2008-01-01

    A proper representation of the air flow in a ventilation duct is crucial for adequate prediction of the deposition velocity of particles. In this paper, the mean turbulent air flow fields are predicted by two different numerical models (the Reynolds stress transport model (RSM) and the realizable k-εmodel). Contours of mean streamwise velocity deduced from the k-ε model are compared with those obtained from the Reynolds stress transport model. Dimensionless deposition velocities of particles in downward and upward ventilation duct flows are also compared based on the flow fields presented by the two different numerical models. Trajectories of the particles are tracked using a one way coupling Lagrangian eddy-particle interaction model. Thousands of individual particles are released in the represented flow, and dimensionless deposition velocities are evaluated for the vertical walls in fully developed smooth vertical downward and upward square duct flows generated by the RSM and realizable k-ε model. The effects of particle diameter, dimensionless relaxation time, flow direction and air speed in vertical upward and downward square duct flows on the particle deposition velocities are discussed. The effects of lift and gravity on the particle deposition velocities are evaluated in vertical flows presented by the RSM. It is shown that the particle deposition velocities based on the RSM and realizable k-εmodel have subtle differences. The flow direction and the lift force significantly affect the particle deposition velocities in vertical duct flows. The simulation results are compared with earlier experimental data and the numerical results for fully developed duct flows. It is shown that the deposition velocities predicted are in agreement with the experimental data and the numerical results

  17. Modelling study of regional deposition of inhaled aerosols with special reference to effects of ventilation asymmetry

    International Nuclear Information System (INIS)

    Nixon, W.; Egan, M.J.

    1987-01-01

    The paper presents the mathematical modelling of aerosol transport and deposition of inhaled aerosols in the lung. Two mathematical models are considered, one assumes the lung to be completely symmetrical, the second incorporates a measure of ventilation inhomogeneity. Both models include the influence of effective axial dispersion. The asymmetrical model is used in the simulations of the radio-bolus inhalation experiments performed by Stahlhofen et al [J. Aerosol Sci. 17, 33], which involved the injection of a bolus at a pre-defined volume towards the end of an inspiration. The impact of the simulation results on regional deposition estimates are discussed. (U.K.)

  18. Modelling and tracer studies of atmospheric dispersion and deposition in regions of complex topography

    International Nuclear Information System (INIS)

    Norden, C.E.

    1981-11-01

    An indium tracer aerosol generating apparatus based on an alcohol/oxygen burner, and an analytical procedure by which filter samples containing tracer material could be analysed quantitatively by means of neutron activation analysis, were developed for use in atmospheric dispersion and deposition studies. A number of series of atmospheric dispersion experiments were conducted in the Richards Bay and Koeberg- Cape Town areas. The results are given, comparing the airbone tracer concentrations measured at ground level with values predicted by means of a numerical model, utilising two to three schemes, varying in sophistication, for calculating the dispersion coefficients. Recommendations are given regarding a dispersion model and dispersion coefficients for regular use in the Koeberg area, and ways for estimating plume trajectories

  19. Model study on acidifying wet deposition in East Asia during wintertime

    Science.gov (United States)

    Han, Zhiwei; Ueda, Hiromasa; Sakurai, Tatsuya

    A regional air quality model (RAQM) has been developed and applied together with an aerosol model to investigate the states and characteristics of wet deposition in East Asia in December 2001. Model simulation is performed with monthly based emission inventory [Streets, D.G., Bond, T.C., Carmichael, G.R., Fernandes, S.D., Fu, Q., He, D., Klimont, Z., Nelson, S. M., Tsai, N.Y., Wang, M.Q., Woo, J.-H., Yarber, K.F., 2003. An inventory of gaseous and primary emissions in Asia in the year 2000. Journal of Geophysical Research 108(D21), 8809] and meteorological fields derived from MM5. Model results are compared with extensive monitoring data including relevant gaseous species and ions in precipitation. The validation demonstrates that this model system is able to represent most of the major physical and chemical processes involved in acid deposition and reproduces concentrations reasonably well, within a factor of 2 of observations in general. The study shows that the regions with pH less than 4.5 are mainly located in southwestern China, parts of the Yangtze Delta, the Yellow Sea and the Korean peninsula, indicating wide regions of acid precipitation in East Asia in wintertime. Japan islands mainly exhibit pH values of 4.5-5.0, whereas over wide areas of northern China, pH values are relatively high (⩾5.0) due to neutralization by alkaline materials such as calcium-laden particles and ammonia, which are more abundant in northern China than that in southern China. While acid rain over most of China is still characterized by sulfur-induced type, considerable areas of eastern China and the western Pacific Rim are found to be more affected by nitric acid than sulfuric acid in acidification of precipitation, which is supposed to result from a combined effect of variations in photochemistry and emission, suggesting the increasing importance of NO x emission in these regions.

  20. Numerical modeling study of the momentum deposition of small amplitude gravity waves in the thermosphere

    Directory of Open Access Journals (Sweden)

    X. Liu

    2013-01-01

    Full Text Available We study the momentum deposition in the thermosphere from the dissipation of small amplitude gravity waves (GWs within a wave packet using a fully nonlinear two-dimensional compressible numerical model. The model solves the nonlinear propagation and dissipation of a GW packet from the stratosphere into the thermosphere with realistic molecular viscosity and thermal diffusivity for various Prandtl numbers. The numerical simulations are performed for GW packets with initial vertical wavelengths (λz ranging from 5 to 50 km. We show that λz decreases in time as a GW packet dissipates in the thermosphere, in agreement with the ray trace results of Vadas and Fritts (2005 (VF05. We also find good agreement for the peak height of the momentum flux (zdiss between our simulations and VF05 for GWs with initial λz ≤ 2π H in an isothermal, windless background, where H is the density scale height. We also confirm that zdiss increases with increasing Prandtl number. We include eddy diffusion in the model, and find that the momentum deposition occurs at lower altitudes and has two separate peaks for GW packets with small initial λz. We also simulate GW packets in a non-isothermal atmosphere. The net λz profile is a competition between its decrease from viscosity and its increase from the increasing background temperature. We find that the wave packet disperses more in the non-isothermal atmosphere, and causes changes to the momentum flux and λz spectra at both early and late times for GW packets with initial λz ≥ 10 km. These effects are caused by the increase in T in the thermosphere, and the decrease in T near the mesopause.

  1. The Sophia Anatomical Infant Nose-Throat (Saint) model: a valuable tool to study aerosol deposition in infants

    NARCIS (Netherlands)

    Janssens, H. M.; de Jongste, J. C.; Fokkens, W. J.; Robben, S. G.; Wouters, K.; Tiddens, H. A.

    2001-01-01

    Relatively little is known about the variables that influence lung deposition of inhaled aerosols in children. A model of the upper airways of an infant could be a useful tool to study these variables in vitro. The objective of this study was to construct an anatomically correct model of the upper

  2. Dry Lung as a Physical Model in Studies of Aerosol Deposition.

    Science.gov (United States)

    Morozov, Victor N; Kanev, Igor L

    2015-10-01

    A new physical model was developed to evaluate the deposition of micro- and nanoaerosol particles (NAPs) into the lungs as a function of size and charges. The model was manufactured of a dry, inflated swine lung produced by Nasco company (Fort Atkinson, WI). The dry lung was cut into two lobes and a conductive tube was glued into the bronchial tube. The upper 1-2-mm-thick layer of the lung lobe was removed with a razor blade to expose the alveoli. The lobe was further enclosed into a plastic bag and placed within a metalized plastic box. The probability of aerosol deposition was calculated by comparing the size distribution of NAPs passed through the lung with that of control, where aerosol passed through a box bypassing the lung. Using this new lung model, it was demonstrated that charged NAPs are deposited inside the lung substantially more efficiently than neutral ones. It was also demonstrated that deposition of neutral NAPs well fits prediction of the Multiple-Path Particle Dosimetry (MPPD) model developed by the Applied Research Associates, Inc. (ARA).

  3. PATTERN DEVELOPMENT FOR MANUFACTURING APPLICATIONS WITH FUSED DEPOSITION MODELLING – A CASE STUDY

    Directory of Open Access Journals (Sweden)

    H. K. Garg

    2013-06-01

    Full Text Available The purpose of this paper is to examine the suitability of fused deposition modelling (FDM, for the production of a pattern that can be used in direct manufacturing applications. In this work, the benchmark was identified and its best part orientation in a FDM machine was located through experimentation. Control charts and process capability histogram were drawn to assess the process capability of the FDM process. The micro hardness of the prepared sample was measured to check the suitability of the process for investment casting applications. Further dimensional accuracy of patterns was established by IT grades as per the ISO standard UNI EN 20286-I (1995. It was observed that the performance indices for all the dimensions in the present study are greater than 1. The study of photo micrographs using SEM gave an insight into the properties of the component (produced by FDM. This study highlights that the tolerance grades for ABS plastics are consistent with the permissible range of tolerance grades as per the ISO standard UNI EN 20286-I (1995 and DIN16901 standard.

  4. An Experimental Model to Study the Impact of Lipid Oxidation on Contact Lens Deposition In Vitro.

    Science.gov (United States)

    Schuett, Burkhardt S; Millar, Thomas J

    2017-09-01

    This study was to establish a controlled in vitro test system to study the effect of lipid oxidation on lipid deposition on contact lenses. Fatty acids with varying degree of unsaturation were oxidized using the Fenton reaction. The degree of lipid oxidation and the lipid moieties formed during the oxidation were identified and estimated by various lipid staining techniques following separation with thin-layer chromatography, and by measuring thiobarbituric acid reactive substances or peroxides in solution. Two different silicone hydrogel-based contact lenses (Balafilcon A and Senofilcon A) were incubated with fatty acids laced with radioactive tracer oxidized to varying degrees, and the amount of lipid deposition was measured using unoxidized lipid samples as controls. The Fenton reaction together with the analytical methods to analyze the lipid oxidation can be used to control oxidation of lipids to a desired amount. In general, saturated fatty acids are not oxidized, the monounsaturated oleic acid produced peroxides while poly-unsaturated lipids initially produced peroxides and then fragmented into reactive aldehydes. Incubation with mildly oxidized lipids (most likely lipid peroxides) resulted in increased lipid deposition on Balafilcon A lenses compared to unoxidized lipids, but this was not observed for Senofilcon A lenses. Further oxidation of the lipids (carbon chain breakup) on the other hand resulted in diminished lipid deposition for both contact lens types. This study provides a method for inducing and controlling lipid oxidation so that the effect of lipid oxidation on contact lens binding can be compared. It could be shown that the degree of lipid oxidation has different effects on the lipid deposition on different contact lens types.

  5. TiOx deposited by magnetron sputtering: a joint modelling and experimental study

    Science.gov (United States)

    Tonneau, R.; Moskovkin, P.; Pflug, A.; Lucas, S.

    2018-05-01

    This paper presents a 3D multiscale simulation approach to model magnetron reactive sputter deposition of TiOx⩽2 at various O2 inlets and its validation against experimental results. The simulation first involves the transport of sputtered material in a vacuum chamber by means of a three-dimensional direct simulation Monte Carlo (DSMC) technique. Second, the film growth at different positions on a 3D substrate is simulated using a kinetic Monte Carlo (kMC) method. When simulating the transport of species in the chamber, wall chemistry reactions are taken into account in order to get the proper content of the reactive species in the volume. Angular and energy distributions of particles are extracted from DSMC and used for film growth modelling by kMC. Along with the simulation, experimental deposition of TiOx coatings on silicon samples placed at different positions on a curved sample holder was performed. The experimental results are in agreement with the simulated ones. For a given coater, the plasma phase hysteresis behaviour, film composition and film morphology are predicted. The used methodology can be applied to any coater and any films. This paves the way to the elaboration of a virtual coater allowing a user to predict composition and morphology of films deposited in silico.

  6. Laboratory measurements and model sensitivity studies of dust deposition ice nucleation

    Directory of Open Access Journals (Sweden)

    G. Kulkarni

    2012-08-01

    Full Text Available We investigated the ice nucleating properties of mineral dust particles to understand the sensitivity of simulated cloud properties to two different representations of contact angle in the Classical Nucleation Theory (CNT. These contact angle representations are based on two sets of laboratory deposition ice nucleation measurements: Arizona Test Dust (ATD particles of 100, 300 and 500 nm sizes were tested at three different temperatures (−25, −30 and −35 °C, and 400 nm ATD and kaolinite dust species were tested at two different temperatures (−30 and −35 °C. These measurements were used to derive the onset relative humidity with respect to ice (RHice required to activate 1% of dust particles as ice nuclei, from which the onset single contact angles were then calculated based on CNT. For the probability density function (PDF representation, parameters of the log-normal contact angle distribution were determined by fitting CNT-predicted activated fraction to the measurements at different RHice. Results show that onset single contact angles vary from ~18 to 24 degrees, while the PDF parameters are sensitive to the measurement conditions (i.e. temperature and dust size. Cloud modeling simulations were performed to understand the sensitivity of cloud properties (i.e. ice number concentration, ice water content, and cloud initiation times to the representation of contact angle and PDF distribution parameters. The model simulations show that cloud properties are sensitive to onset single contact angles and PDF distribution parameters. The comparison of our experimental results with other studies shows that under similar measurement conditions the onset single contact angles are consistent within ±2.0 degrees, while our derived PDF parameters have larger discrepancies.

  7. Computational study of wax deposition in pipeline

    Science.gov (United States)

    Duan, Jimiao; Gong, Jing; Liu, Huishu

    2013-07-01

    Wax deposition in subsea pipelines is one of the flow assurance problems for oil and gas production. In contrast to many studies about single phase wax deposition, gas-oil wax deposition studies are very limited. The wax deposition mechanism and model prediction are restricted by many factors such as hydrodynamic and thermal when multiphase flow is involved. Wax deposition modeling becomes complicated under multiphase flowing conditions. wax deposition is depended by the flow pattern. The stratified flow is one of the most common flow patterns in the actual subsea gas-oil flowing conditions. In this work, numerical methods are used to study wax deposition in oil-gas stratified flow through a pipe. Based on the flow analysis about stratified flow, the non-isothermal heat and mass transfer is calculated. The temperature profile of the oil and the concentration profile of wax in oil are obtained. The change of the oil-gas interface i.e. the liquid holdup throughout the pipe must be taken into the heat and mass balance. The valid wax deposition surface must be taken into the wax deposition modeling by establishing function of the liquid holdup and the wetted area by oil. The molecular diffusion is as the deposition mechanism. The increase of the wax fraction in the deposit as a function of time depends on the mass flux from the oil deposit interface into the gel and the growth of the deposit thickness depends on the difference between the mass flux from the bulk oil to the oil deposit interface and the mass flux from the interface into the deposit. In addition, the growth of the wax deposit as a function of time along with the effect oil flow rate, gas flow rate and the inlet temperature are discussed. The presence of gas significantly reduces the severity of wax deposition by altering the heat and mass transfer characteristics.

  8. Calcium pyrophosphate crystal deposition. An in vitro study using a gelatin matrix model.

    Science.gov (United States)

    Mandel, N S; Mandel, G S; Carroll, D J; Halverson, P B

    1984-07-01

    Deposition of crystalline triclinic (t) and monoclinic (m) calcium pyrophosphate dihydrate (CPPD) in fibrocartilage and articular cartilage is the hallmark of chondrocalcinosis. Using biologic grade gelatin to model this crystal growth process, t-CPPD, m-CPPD, amorphous calcium pyrophosphate, orthorhombic calcium pyrophosphate tetrahydrate (o-CPPT), and 3 mixed calcium/sodium pyrophosphate salts were grown at physiologic pH. Amorphous and o-CPPT appeared to be kinetic precursor crystals in the formation of t-CPPD and m-CPPD. Optimal concentration ranges for the different crystals were determined.

  9. A coupled modelling effort to study the fate of contaminated sediments downstream of the Coles Hill deposit, Virginia, USA

    Directory of Open Access Journals (Sweden)

    C. F. Castro-Bolinaga

    2015-03-01

    Full Text Available This paper presents the preliminary results of a coupled modelling effort to study the fate of tailings (radioactive waste-by product downstream of the Coles Hill uranium deposit located in Virginia, USA. The implementation of the overall modelling process includes a one-dimensional hydraulic model to qualitatively characterize the sediment transport process under severe flooding conditions downstream of the potential mining site, a two-dimensional ANSYS Fluent model to simulate the release of tailings from a containment cell located partially above the local ground surface into the nearby streams, and a one-dimensional finite-volume sediment transport model to examine the propagation of a tailings sediment pulse in the river network located downstream. The findings of this investigation aim to assist in estimating the potential impacts that tailings would have if they were transported into rivers and reservoirs located downstream of the Coles Hill deposit that serve as municipal drinking water supplies.

  10. The feasibility study on fabrication customized orthotic insole using fused deposition modelling (FDM)

    Science.gov (United States)

    Yarwindran, M.; Ibrahim, M.; Raveverma, P.

    2017-04-01

    There are many important roles of the orthotic insoles, such as for the convenience purpose of diabetic patient's foot problem, and also to enhance athlete's performance in sports. Therefore, highly customised insoles were in demand, where it has to be fabricated by moulding plaster of Paris on the person's leg to customise the insole. The main purpose of the paper is to study the ability to implement additive manufacturing technology in the fabrication process of customised orthotics insole. The recent invention of flexible material (Filaflex) in Fused Deposition Modelling is the most significant reason that makes this fabrication process possible. By implementing a new approach to the 3D scanning of the foot, we produced the computer-aided drafting (CAD) drawing which was able to modify to desired shape and dimension. After the editing has been completed, the file was converted to Stereolithography format file (STL) as to enable it to be printed using Makerware or any other related software by sending command (G-code) to Flashforge 3D printer. The printed insole was tested its fit, form and function (also known as 3F). In the end, printed insole performs the function test which measures the plantar pressure of the foot compared with bare foot. The results show that the insole distributes pressure well throughout the foot surface, in which it reduced the peak pressure to half from 218KPa to 109KPa. Hence, it is concluded that the method proposed in this paper can produce a functional insole so that it can be the alternative way to make customised orthotic insoles.

  11. Monte Carlo study of radial energy deposition from primary and secondary particles for narrow and large proton beamlet source models

    International Nuclear Information System (INIS)

    Peeler, Christopher R; Titt, Uwe

    2012-01-01

    In spot-scanning intensity-modulated proton therapy, numerous unmodulated proton beam spots are delivered over a target volume to produce a prescribed dose distribution. To accurately model field size-dependent output factors for beam spots, the energy deposition at positions radial to the central axis of the beam must be characterized. In this study, we determined the difference in the central axis dose for spot-scanned fields that results from secondary particle doses by investigating energy deposition radial to the proton beam central axis resulting from primary protons and secondary particles for mathematical point source and distributed source models. The largest difference in the central axis dose from secondary particles resulting from the use of a mathematical point source and a distributed source model was approximately 0.43%. Thus, we conclude that the central axis dose for a spot-scanned field is effectively independent of the source model used to calculate the secondary particle dose. (paper)

  12. A multi-model study of the hemispheric transport and deposition of oxidised nitrogen

    International Nuclear Information System (INIS)

    Sanderson, M.G.; Pringle, K.J.; Dentener, F.J.; Cuvelier, C.; Marmer, E.; Fiore, A.M.; Horowitz, L.W.; Keating, T.J.; Zuber, A.; Atherton, C.S.; Bergmann, D.J.; Diehl, T.; Duncan, B.N.; Doherty, R. M.; MacKenzie, I.A.; Hess, P.; Jacob, D.J.; Park, R.; Jonson, J.E.; Wind, P.; Kaminski, J.W.; Lupu, A.; Mancini, E.; Pitari, G.; Prather, M.J.; Schroeder, S.; Schultz, M.G.; Shindell, D.T.; Shindell, D.T.; Szopa, S.; Wild, O.

    2008-01-01

    Fifteen chemistry-transport models are used to quantify, for the first time, the export of oxidised nitrogen (NOy) to and from four regions (Europe, North America, South Asia, and East Asia), and to estimate the uncertainty in the results. Between 12 and 24% of the NOx emitted is exported from each region annually. The strongest impact of each source region on a foreign region is: Europe on East Asia, North America on Europe, South Asia on East Asia, and East Asia on North America. Europe exports the most NOy, and East Asia the least. East Asia receives the most NOy from the other regions. Between 8 and 15% of NOx emitted in each region is transported over distances larger than 1000 km, with 3-10% ultimately deposited over the foreign regions. (authors)

  13. Scenario and parameter studies on global deposition of radioactivity using the computer model GLODEP2

    International Nuclear Information System (INIS)

    Shapiro, C.S.

    1984-08-01

    The GLODEP2 computer code was utilized to determine biological impact to humans on a global scale using up-to-date estimates of biological risk. These risk factors use varied biological damage models for assessing effects. All the doses reported are the unsheltered, unweathered, smooth terrain, external gamma dose. We assume the unperturbed atmosphere in determining injection and deposition. Effects due to ''nuclear winter'' may invalidate this assumption. The calculations also include scenarios that attempt to assess the impact of the changing nature of the nuclear stockpile. In particular, the shift from larger to smaller yield nuclear devices significantly changes the injection pattern into the atmosphere, and hence significantly affects the radiation doses that ensue. We have also looked at injections into the equatorial atmosphere. In total, we report here the results for 8 scenarios. 10 refs., 6 figs., 11 tabs

  14. Erosion, Transportation, and Deposition on Outer Solar System Satellites: Landform Evolution Modeling Studies

    Science.gov (United States)

    Moore, Jeffrey Morgan; Howard, Alan D.; Schenk, Paul M.

    2013-01-01

    Mass movement and landform degradation reduces topographic relief by moving surface materials to a lower gravitational potential. In addition to the obvious role of gravity, abrasive mechanical erosion plays a role, often in combination with the lowering of cohesion, which allows disaggregation of the relief-forming material. The identification of specific landform types associated with mass movement and landform degradation provides information about local sediment particle size and abundance and transportation processes. Generally, mass movements can be classified in terms of the particle sizes of the transported material and the speed the material moved during transport. Most degradation on outer planet satellites appears consistent with sliding or slumping, impact erosion, and regolith evolution. Some satellites, such as Callisto and perhaps Hyperion and Iapetus, have an appearance that implies that some additional process is at work, most likely sublimation-driven landform modification and mass wasting. A variant on this process is thermally driven frost segregation as seen on all three icy Galilean satellites and perhaps elsewhere. Titan is unique among outer planet satellites in that Aeolian and fluvial processes also operate to erode, transport, and deposit material. We will evaluate the sequence and extent of various landform-modifying erosional and volatile redistribution processes that have shaped these icy satellites using a 3-D model that simulates the following surface and subsurface processes: 1) sublimation and re-condensation of volatiles; 2) development of refractory lag deposits; 3) disaggregation and downward sloughing of surficial material; 4) radiative heating/cooling of the surface (including reflection, emission, and shadowing by other surface elements); 5) thermal diffusion; and 6) vapor diffusion. The model will provide explicit simulations of landform development and thusly predicts the topographic and volatile evolution of the surface

  15. Laboratory model study of newly deposited dredger fills using improved multiple-vacuum preloading technique

    Directory of Open Access Journals (Sweden)

    Jingjin Liu

    2017-10-01

    Full Text Available Problems continue to be encountered concerning the traditional vacuum preloading method in field during the treatment of newly deposited dredger fills. In this paper, an improved multiple-vacuum preloading method was developed to consolidate newly dredger fills that are hydraulically placed in seawater for land reclamation in Lingang Industrial Zone of Tianjin City, China. With this multiple-vacuum preloading method, the newly deposited dredger fills could be treated effectively by adopting a novel moisture separator and a rapid improvement technique without sand cushion. A series of model tests was conducted in the laboratory for comparing the results from the multiple-vacuum preloading method and the traditional one. Ten piezometers and settlement plates were installed to measure the variations in excess pore water pressures and moisture content, and vane shear strength was measured at different positions. The testing results indicate that water discharge–time curves obtained by the traditional vacuum preloading method can be divided into three phases: rapid growth phase, slow growth phase, and steady phase. According to the process of fluid flow concentrated along tiny ripples and building of larger channels inside soils during the whole vacuum loading process, the fluctuations of pore water pressure during each loading step are divided into three phases: steady phase, rapid dissipation phase, and slow dissipation phase. An optimal loading pattern which could have a best treatment effect was proposed for calculating the water discharge and pore water pressure of soil using the improved multiple-vacuum preloading method. For the newly deposited dredger fills at Lingang Industrial Zone of Tianjin City, the best loading step was 20 kPa and the loading of 40–50 kPa produced the highest drainage consolidation. The measured moisture content and vane shear strength were discussed in terms of the effect of reinforcement, both of which indicate

  16. Sediment transport and deposition on a river-dominated tidal flat: An idealized model study

    Science.gov (United States)

    Sherwood, Christopher R.; Chen, Shih-Nan; Geyer, W. Rockwell; Ralston, David K.

    2010-01-01

    A 3-D hydrodynamic model is used to investigate how different size classes of river-derived sediment are transported, exported and trapped on an idealized, river-dominated tidal flat. The model is composed of a river channel flanked by sloping tidal flats, a configuration motivated by the intertidal region of the Skagit River mouth in Washington State, United States. It is forced by mixed tides and a pulse of freshwater and sediment with various settling velocities. In this system, the river not only influences stratification but also contributes a significant cross-shore transport. As a result, the bottom stress is strongly ebb-dominated in the channel because of the seaward advance of strong river flow as the tidal flats drain during ebbs. Sediment deposition patterns and mass budgets are sensitive to settling velocity. The lateral sediment spreading scales with an advective distance (settling time multiplied by lateral flow speed), thereby confining the fast settling sediment classes in the channel. Residual sediment transport is landward on the flats, because of settling lag, but is strongly seaward in the channel. The seaward transport mainly occurs during big ebbs and is controlled by a length scale ratio Ld/XWL, where Ld is a cross-shore advective distance (settling time multiplied by river outlet velocity), and XWL is the immersed cross-shore length of the intertidal zone. Sediment trapping requires Ld/XWL stratification and reducing tidal range both favor sediment trapping, whereas varying channel geometries and asymmetry of tides has relatively small impacts. Implications of the modeling results on the south Skagit intertidal region are discussed.

  17. Advanced deposition model for thermal activated chemical vapor deposition

    Science.gov (United States)

    Cai, Dang

    Thermal Activated Chemical Vapor Deposition (TACVD) is defined as the formation of a stable solid product on a heated substrate surface from chemical reactions and/or dissociation of gaseous reactants in an activated environment. It has become an essential process for producing solid film, bulk material, coating, fibers, powders and monolithic components. Global market of CVD products has reached multi billions dollars for each year. In the recent years CVD process has been extensively used to manufacture semiconductors and other electronic components such as polysilicon, AlN and GaN. Extensive research effort has been directed to improve deposition quality and throughput. To obtain fast and high quality deposition, operational conditions such as temperature, pressure, fluid velocity and species concentration and geometry conditions such as source-substrate distance need to be well controlled in a CVD system. This thesis will focus on design of CVD processes through understanding the transport and reaction phenomena in the growth reactor. Since the in situ monitor is almost impossible for CVD reactor, many industrial resources have been expended to determine the optimum design by semi-empirical methods and trial-and-error procedures. This approach has allowed the achievement of improvements in the deposition sequence, but begins to show its limitations, as this method cannot always fulfill the more and more stringent specifications of the industry. To resolve this problem, numerical simulation is widely used in studying the growth techniques. The difficulty of numerical simulation of TACVD crystal growth process lies in the simulation of gas phase and surface reactions, especially the latter one, due to the fact that very limited kinetic information is available in the open literature. In this thesis, an advanced deposition model was developed to study the multi-component fluid flow, homogeneous gas phase reactions inside the reactor chamber, heterogeneous surface

  18. Particle Tracking and Deposition from CFD Simulations using a Viscoelastic Particle Model

    NARCIS (Netherlands)

    Losurdo, M.

    2009-01-01

    In the present dissertation the mathematical modelling of particle deposition is studied and the solution algorithms for particle tracking, deposition and deposit growth are developed. Particle deposition is modelled according to mechanical impact and contact mechanics taking into account the

  19. Studies on Effect of Fused Deposition Modelling Process Parameters on Ultimate Tensile Strength and Dimensional Accuracy of Nylon

    Science.gov (United States)

    Basavaraj, C. K.; Vishwas, M.

    2016-09-01

    This paper discusses the process parameters for fused deposition modelling (FDM). Layer thickness, Orientation angle and shell thickness are the process variables considered for studies. Ultimate tensile strength, dimensional accuracy and manufacturing time are the response parameters. For number of experimental runs the taguchi's L9 orthogonal array is used. Taguchis S/N ratio was used to identify a set of process parameters which give good results for respective response characteristics. Effectiveness of each parameter is investigated by using analysis of variance. The material used for the studies of process parameter is Nylon.

  20. The polar layered deposits on Mars: Inference from thermal inertia modeling and geologic studies

    Science.gov (United States)

    Herkenhoff, K. E.

    1992-01-01

    It is widely believed that the Martian polar layered deposits record climate variations over at least the last 10 to 100 m.y., but the details of the processes involved and their relative roles in layer formation and evolution remain obscure. Weathering of the Martian layered deposits by sublimation of water ice can account for the thermal inertias, water vapor abundances, and geologic relationships observed in the Martian polar regions. The nonvolatile components of the layered deposits appears to consist mainly of bright red dust, with small amounts of dark dust. Dark dust, perhaps similar to the magnetic material found at the Viking Lander sites, may preferentially form filamentary residue particles upon weathering of the deposits. Once eroded, these particles may saltate to form the dark dunes found in both polar regions. This scenario for the origin and evolution of the dark material within the polar layered deposits is consistent with the available imaging and thermal data. Further experimental measurements of the thermophysical properties of magnetite and maghemite under Martian conditions are needed to better test this hypothesis.

  1. Econometrics Models for Copper Recovery: A Case Study of North Waziristan-Copper Deposits

    International Nuclear Information System (INIS)

    Ali, S.; Khan, M.M.

    2010-01-01

    Fourteen econometrics models have been developed to evaluate the effects of various flotation process variables like, Propyl xanthate (X/sub 1/g/tonne), pH (X/sub 2/,) Sodium Cyanide (X/sub 3/ g/tonne), Sodium sulphide (X/sub 4/ g/tonne), Frother (X/sub 5/ g/tonne), Pulp density (X/sub 6/ w/vol), and Conditioning time (X/sub 7/ minute) on the copper recovery YR North Waziristan-NWFP Pakistan. Ordinary Least Square OLS method has been applied as an analytical technique for regression analysis. It has been concluded in this study that model given in equation 7 is best model among all. This equation shows that with the increase of one unit of X/sub 1/, Y/sub R/ will increase 0.05 units keeping all other variables constant. (author)

  2. Spatiotemporal Dispersal and Deposition of Fish Farm Wastes: A Model Study from Central Norway

    Directory of Open Access Journals (Sweden)

    Ole J. Broch

    2017-06-01

    Full Text Available A spatially explicit coupled hydrodynamic-mass transport model system was used to simulate dispersal of particulate organic matter from Atlantic salmon (Salmo salar farming in central Norway. Model setups of 32 m horizontal resolution were run for periods of up to 650 days for 3 sites of different oceanographic characteristics: one fjord location, one medium-exposed location influenced by fjord water, and one coastal location. Records on feed used for each cage at each location were converted to feces released based on a published mass balance model. The results from the simulations were compared with scores from corresponding mandatory benthic surveys (MOM-B of the sediment layer beneath the farms. The correspondence between simulated and measured thickness of the sediment layer was good, and improved with the inclusion of resuspension processes. At all sites the distribution of organic matter in the bottom layer was non-homogeneous, with significant temporal variation and transport and settling of matter up to at least 0.5 km away from one of the farms. Our results indicate that the monitoring practice used in Norway until now, with a few sediment grab samples taken mainly within the fish farm, may not adequately determine the areal impacts of all salmon farming operations. The patchy distribution of organic matter and the correspondence between simulation and survey results is attributed to the use of full 3D current fields of a high spatiotemporal resolution and a good model for resuspension processes that some previous model studies have failed to properly account for.

  3. Modeling transport and deposition of contaminants to ecosystems of concern: a case study for the Laurentian Great Lakes

    International Nuclear Information System (INIS)

    MacLeod, Matthew; Mackay, Don

    2004-01-01

    Transfer efficiency (TE) is introduced as a model output that can be used to characterize the relative ability of chemicals to be transported in the environment and deposited to specific target ecosystems. We illustrate this concept by applying the Berkeley-Trent North American contaminant fate model (BETR North America) to identify organic chemicals with properties that result in efficient atmospheric transport and deposition to the Laurentian Great Lakes. By systematically applying the model to hypothetical organic chemicals that span a wide range of environmental partitioning properties, we identify combinations of properties that favor efficient transport and deposition to the Lakes. Five classes of chemicals are identified based on dominant transport and deposition pathways, and specific examples of chemicals in each class are identified and discussed. The role of vegetation in scavenging chemicals from the atmosphere is assessed, and found to have a negligible influence on transfer efficiency to the Great Lakes. Results indicate chemicals with octanol-water (K ow ) and air-water (K aw ) partition coefficients in the range of 10 5 -10 7 and 10 -4 -10 -1 combine efficient transport and deposition to the Great Lakes with potential for biaccumulation in the aquatic food web once they are deposited. A method of estimating the time scale for atmospheric transport and deposition process is suggested, and the effects of degrading reactions in the atmosphere and meteorological conditions on transport efficiency of different classes of chemicals are discussed. In total, this approach provides a method of identifying chemicals that are subject to long-range transport and deposition to specific target ecosystems as a result of their partitioning and persistence characteristics. Supported by an appropriate contaminant fate model, the approach can be applied to any target ecosystem of concern. - Transfer Efficiency is defined as a model-based measure of sources of POPs to

  4. Modeling transport and deposition of contaminants to ecosystems of concern: a case study for the Laurentian Great Lakes.

    Science.gov (United States)

    MacLeod, Matthew; Mackay, Don

    2004-01-01

    Transfer efficiency (TE) is introduced as a model output that can be used to characterize the relative ability of chemicals to be transported in the environment and deposited to specific target ecosystems. We illustrate this concept by applying the Berkeley-Trent North American contaminant fate model (BETR North America) to identify organic chemicals with properties that result in efficient atmospheric transport and deposition to the Laurentian Great Lakes. By systematically applying the model to hypothetical organic chemicals that span a wide range of environmental partitioning properties, we identify combinations of properties that favor efficient transport and deposition to the Lakes. Five classes of chemicals are identified based on dominant transport and deposition pathways, and specific examples of chemicals in each class are identified and discussed. The role of vegetation in scavenging chemicals from the atmosphere is assessed, and found to have a negligible influence on transfer efficiency to the Great Lakes. Results indicate chemicals with octanol-water (K(ow)) and air-water (K(aw)) partition coefficients in the range of 10(5)-10(7) and 10(-4)-10(-1) combine efficient transport and deposition to the Great Lakes with potential for biaccumulation in the aquatic food web once they are deposited. A method of estimating the time scale for atmospheric transport and deposition process is suggested, and the effects of degrading reactions in the atmosphere and meteorological conditions on transport efficiency of different classes of chemicals are discussed. In total, this approach provides a method of identifying chemicals that are subject to long-range transport and deposition to specific target ecosystems as a result of their partitioning and persistence characteristics. Supported by an appropriate contaminant fate model, the approach can be applied to any target ecosystem of concern.

  5. Experimental Study of ABS Material Shrinkage and Deformation Based on Fused Deposition Modeling

    OpenAIRE

    Xu Yaodong

    2016-01-01

    The CAD model can be directly converted into physical model by rapid prototyping , which provides more convenient means for concurrent design in physical verification. However, the deformation of the material shrinkage can cause large deviation of the molding size in CAD model transforming to physical model. In order to ensure the reasonable assembly of the rapid prototyping part, the forming experiment of ABS material was carried out by the principle of FDM. Through regression analysis, a li...

  6. Respiratory trace deposition models. Final report

    International Nuclear Information System (INIS)

    Yeh, H.C.

    1980-03-01

    Respiratory tract characteristics of four mammalian species (human, dog, rat and Syrian hamster) were studied, using replica lung casts. An in situ casting techniques was developed for making the casts. Based on an idealized branch model, over 38,000 records of airway segment diameters, lengths, branching angles and gravity angles were obtained from measurements of two humans, two Beagle dogs, two rats and one Syrian hamster. From examination of the trimmed casts and morphometric data, it appeared that the structure of the human airway is closer to a dichotomous structure, whereas for dog, rat and hamster, it is monopodial. Flow velocity in the trachea and major bronchi in living Beagle dogs was measured using an implanted, subminiaturized, heated film anemometer. A physical model was developed to simulate the regional deposition characteristics proposed by the Task Group on Lung Dynamics of the ICRP. Various simulation modules for the nasopharyngeal (NP), tracheobronchial (TB) and pulmonary (P) compartments were designed and tested. Three types of monodisperse aerosols were developed for animal inhalation studies. Fifty Syrian hamsters and 50 rats were exposed to five different sizes of monodisperse fused aluminosilicate particles labeled with 169 Yb. Anatomical lung models were developed for four species (human, Beagle dog, rat and Syrian hamster) that were based on detailed morphometric measurements of replica lung casts. Emphasis was placed on developing a lobar typical-path lung model and on developing a modeling technique which could be applied to various mammalian species. A set of particle deposition equations for deposition caused by inertial impaction, sedimentation, and diffusion were developed. Theoretical models of particle deposition were developed based on these equations and on the anatomical lung models

  7. Localized Carbon Deposition in Solid Oxide Electrolysis Cells Studied By Multiphysics Modeling

    DEFF Research Database (Denmark)

    Navasa, Maria; Graves, Christopher R.; Frandsen, Henrik Lund

    2016-01-01

    Modeling for optimizing performance has attracted substantial research efforts in the last twenty years with special focus on solid oxide fuel cells (SOFCs). However, limited amount of the modeling work has been focused on the solid oxide electrolysis cell (SOEC) operation mode and even less...

  8. Experimental Study of ABS Material Shrinkage and Deformation Based on Fused Deposition Modeling

    Directory of Open Access Journals (Sweden)

    Xu Yaodong

    2016-01-01

    Full Text Available The CAD model can be directly converted into physical model by rapid prototyping , which provides more convenient means for concurrent design in physical verification. However, the deformation of the material shrinkage can cause large deviation of the molding size in CAD model transforming to physical model. In order to ensure the reasonable assembly of the rapid prototyping part, the forming experiment of ABS material was carried out by the principle of FDM. Through regression analysis, a linear relationship with the molding shrinkage and model size was found Meanwhile, deforming mechanism of prototyping parts was analyzed. The rationality of assembly and quality of print parts can be ensured by these law of pre-process.

  9. Dry deposition models for radionuclides dispersed in air: a new approach for deposition velocity evaluation schema

    Science.gov (United States)

    Giardina, M.; Buffa, P.; Cervone, A.; De Rosa, F.; Lombardo, C.; Casamirra, M.

    2017-11-01

    In the framework of a National Research Program funded by the Italian Minister of Economic Development, the Department of Energy, Information Engineering and Mathematical Models (DEIM) of Palermo University and ENEA Research Centre of Bologna, Italy are performing several research activities to study physical models and mathematical approaches aimed at investigating dry deposition mechanisms of radioactive pollutants. On the basis of such studies, a new approach to evaluate the dry deposition velocity for particles is proposed. Comparisons with some literature experimental data show that the proposed dry deposition scheme can capture the main phenomena involved in the dry deposition process successfully.

  10. Deposition and flux of sediment from the Po River, Italy: An idealized and wintertime numerical modeling study

    Science.gov (United States)

    Bever, A.J.; Harris, C.K.; Sherwood, C.R.; Signell, R.P.

    2009-01-01

    Recent studies of sediment dynamics and clinoform development in the northern Adriatic Sea focused on winter 2002-2003 and provided the data and motivation for development of a detailed sediment-transport model for the area near the Po River delta. We used both idealized test cases and more realistic simulations to improve our understanding of seasonal sediment dynamics there. We also investigated the relationship between physical processes and the observed depositional products; e.g. the accumulation of sediment very near the Po River distributary mouths. Sediment transport near the Po River was evaluated using a three-dimensional ocean model coupled to sediment-transport calculations that included wave- and current-induced resuspension, suspended-sediment transport, multiple grain classes, and fluvial input from the Po River. High-resolution estimates from available meteorological and wave models were used to specify wind, wave, and meteorological forcing. Model results indicated that more than half of the discharged sediment remained within 15??km of the Po River distributary mouths, even after two months of intensive reworking by winter storms. During floods of the Po River, transport in the middle to upper water column dominated sediment fluxes. Otherwise, sediment fluxes from the subaqueous portion of the delta were confined to the bottom few meters of the water column, and correlated with increases in current speed and wave energy. Spatial and temporal variation in wind velocities determined depositional patterns and the directions of sediment transport. Northeasterly Bora winds produced relatively more eastward transport, while southwesterly Sirocco winds generated fluxes towards both the north and the south. Eastward transport accounted for the majority of the sediment exported from the subaqueous delta, most likely due to the frequent occurrence of Bora conditions. Progradation of the Po River delta into the Adriatic Sea may restrict the formation of the

  11. Field, model, and computer simulation study of some aspects of the origin and distribution of Colorado Plateau-type uranium deposits

    Science.gov (United States)

    Ethridge, F.G.; Sunada, D.K.; Tyler, Noel; Andrews, Sarah

    1982-01-01

    Numerous hypotheses have been proposed to account for the nature and distribution of tabular uranium and vanadium-uranium deposits of the Colorado Plateau. In one of these hypotheses it is suggested that the deposits resulted from geochemical reactions at the interface between a relatively stagnant groundwater solution and a dynamic, ore-carrying groundwater solution which permeated the host sandstones (Shawe, 1956; Granger, et al., 1961; Granger, 1968, 1976; and Granger and Warren, 1979). The study described here was designed to investigate some aspects of this hypothesis, particularly the nature of fluid flow in sands and sandstones, the nature and distribution of deposits, and the relations between the deposits and the host sandstones. The investigation, which was divided into three phases, involved physical model, field, and computer simulation studies. During the initial phase of the investigation, physical model studies were conducted in porous-media flumes. These studies verified the fact that humic acid precipitates could form at the interface between a humic acid solution and a potassium aluminum sulfate solution and that the nature and distribution of these precipitates were related to flow phenomena and to the nature and distribution of the host porous-media. During the second phase of the investigation field studies of permeability and porosity patterns in Holocene stream deposits were investigated and the data obtained were used to design more realistic porous media models. These model studies, which simulated actual stream deposits, demonstrated that precipitates possess many characteristics, in terms of their nature and relation to host sandstones, that are similar to ore deposits of the Colorado Plateau. The final phase of the investigation involved field studies of actual deposits, additional model studies in a large indoor flume, and computer simulation studies. The field investigations provided an up-to-date interpretation of the depositional

  12. Modelling asphaltene deposition in turbulent pipeline flows

    Energy Technology Data Exchange (ETDEWEB)

    Eskin, D.; Ratulowski, J.; Akbarzadeh, K.; Pan, S. [Schlumberg DBR Technology Center (Canada)

    2011-06-15

    Asphaltene deposition is one of the important problems of oil production that requires accurate predictive modeling. A model of asphaltene deposition in a turbulent pipe flow is introduced in this paper. A Couette device is employed to perform experiments. There are two major modules in this model. (1) A model of particle size distribution evolution along a pipe - the concept of 'critical particle size' is introduced. Only particles smaller than the critical particle size may deposit. (2) A model of particle transport to the wall. The major mechanism of particle transport to the wall is the Brownian motion. The model developed contains three major tuning parameters that are determined experimentally using a Couette device: particle-particle collision efficiency, particle-wall sticking efficiency, and particle critical size. Performance of the deposition model for a pipeline with the coefficients obtained using a laboratory Couette device is also illustrated in this paper.

  13. Stratiform chromite deposit model: Chapter E in Mineral deposit models for resource assessment

    Science.gov (United States)

    Schulte, Ruth F.; Taylor, Ryan D.; Piatak, Nadine M.; Seal, Robert R.

    2012-01-01

    A new descriptive stratiform chromite deposit model was prepared which will provide a framework for understanding the characteristics of stratiform chromite deposits worldwide. Previous stratiform chromite deposit models developed by the U.S. Geological Survey (USGS) have been referred to as Bushveld chromium, because the Bushveld Complex in South Africa is the only stratified, mafic-ultramafic intrusion presently mined for chromite and is the most intensely researched. As part of the on-going effort by the USGS Mineral Resources Program to update existing deposit models for the upcoming national mineral resource assessment, this revised stratiform chromite deposit model includes new data on the geological, mineralogical, geophysical, and geochemical attributes of stratiform chromite deposits worldwide. This model will be a valuable tool in future chromite resource and environmental assessments and supplement previously published models used for mineral resource evaluation.

  14. A Review of Variable Slicing in Fused Deposition Modeling

    Science.gov (United States)

    Nadiyapara, Hitesh Hirjibhai; Pande, Sarang

    2017-06-01

    The paper presents a literature survey in the field of fused deposition of plastic wires especially in the field of slicing and deposition using extrusion of thermoplastic wires. Various researchers working in the field of computation of deposition path have used their algorithms for variable slicing. In the study, a flowchart has also been proposed for the slicing and deposition process. The algorithm already been developed by previous researcher will be used to be implemented on the fused deposition modelling machine. To demonstrate the capabilities of the fused deposition modeling machine a case study has been taken. It uses a manipulated G-code to be fed to the fused deposition modeling machine. Two types of slicing strategies, namely uniform slicing and variable slicing have been evaluated. In the uniform slicing, the slice thickness has been used for deposition is varying from 0.1 to 0.4 mm. In the variable slicing, thickness has been varied from 0.1 in the polar region to 0.4 in the equatorial region Time required and the number of slices required to deposit a hemisphere of 20 mm diameter have been compared with that using the variable slicing.

  15. Study of materials and machines for 3D printed large-scale, flexible electronic structures using fused deposition modeling

    Science.gov (United States)

    Hwang, Seyeon

    The 3 dimensional printing (3DP), called to additive manufacturing (AM) or rapid prototyping (RP), is emerged to revolutionize manufacturing and completely transform how products are designed and fabricated. A great deal of research activities have been carried out to apply this new technology to a variety of fields. In spite of many endeavors, much more research is still required to perfect the processes of the 3D printing techniques especially in the area of the large-scale additive manufacturing and flexible printed electronics. The principles of various 3D printing processes are briefly outlined in the Introduction Section. New types of thermoplastic polymer composites aiming to specified functional applications are also introduced in this section. Chapter 2 shows studies about the metal/polymer composite filaments for fused deposition modeling (FDM) process. Various metal particles, copper and iron particles, are added into thermoplastics polymer matrices as the reinforcement filler. The thermo-mechanical properties, such as thermal conductivity, hardness, tensile strength, and fracture mechanism, of composites are tested to figure out the effects of metal fillers on 3D printed composite structures for the large-scale printing process. In Chapter 3, carbon/polymer composite filaments are developed by a simple mechanical blending process with an aim of fabricating the flexible 3D printed electronics as a single structure. Various types of carbon particles consisting of multi-wall carbon nanotube (MWCNT), conductive carbon black (CCB), and graphite are used as the conductive fillers to provide the thermoplastic polyurethane (TPU) with improved electrical conductivity. The mechanical behavior and conduction mechanisms of the developed composite materials are observed in terms of the loading amount of carbon fillers in this section. Finally, the prototype flexible electronics are modeled and manufactured by the FDM process using Carbon/TPU composite filaments and

  16. Uranium deposits of Gabon and Oklo reactors. Metallogenic model for rich deposits of the lower proterozoic

    International Nuclear Information System (INIS)

    Gauthier-Lafaye, F.

    1986-05-01

    The geology of the Franceville basin (Gabon) is examined: stratigraphy, tectonics and geodynamics. The mobile zone of the Ogooue is specially studied: lithology, metamorphism and tectonics, isotopic geochronologic data are given. The different uranium deposits are described. A whole chapter is devoted to the study of Oklo natural nuclear reactor. A metallogenic model is proposed evidencing conditions required for deposit genesis. Tectonics, microstructures sedimentology, organic matter, diagenesis and uraniferous mineralizations are examined [fr

  17. Accuracy of three-dimensional dental resin models created by fused deposition modeling, stereolithography, and Polyjet prototype technologies:A comparative study.

    Science.gov (United States)

    Rebong, Raymund E; Stewart, Kelton T; Utreja, Achint; Ghoneima, Ahmed A

    2018-03-06

    The aim of this study was to assess the dimensional accuracy of fused deposition modeling (FDM)-, Polyjet-, and stereolithography (SLA)-produced models by comparing them to traditional plaster casts. A total of 12 maxillary and mandibular posttreatment orthodontic plaster casts were selected from the archives of the Orthodontic Department at the Indiana University School of Dentistry. Plaster models were scanned, saved as stereolithography files, and printed as physical models using three different three-dimensional (3D) printers: Makerbot Replicator (FDM), 3D Systems SLA 6000 (SLA), and Objet Eden500V (Polyjet). A digital caliper was used to obtain measurements on the original plaster models as well as on the printed resin models. Comparison between the 3D printed models and the plaster casts showed no statistically significant differences in most of the parameters. However, FDM was significantly higher on average than were plaster casts in maxillary left mixed plane (MxL-MP) and mandibular intermolar width (Md-IMW). Polyjet was significantly higher on average than were plaster casts in maxillary intercanine width (Mx-ICW), mandibular intercanine width (Md-ICW), and mandibular left mixed plane (MdL-MP). Polyjet was significantly lower on average than were plaster casts in maxillary right vertical plane (MxR-vertical), maxillary left vertical plane (MxL-vertical), mandibular right anteroposterior plane (MdR-AP), mandibular right vertical plane (MdR-vertical), and mandibular left vertical plane (MdL-vertical). SLA was significantly higher on average than were plaster casts in MxL-MP, Md-ICW, and overbite. SLA was significantly lower on average than were plaster casts in MdR-vertical and MdL-vertical. Dental models reconstructed by FDM technology had the fewest dimensional measurement differences compared to plaster models.

  18. Experimental Research and Modeling of Particle Deposition in Ventilation Ducts

    Directory of Open Access Journals (Sweden)

    Hongming Fan

    2013-01-01

    Full Text Available The model to predict particle deposition velocity on rough walls in fully developed turbulent duct flows has been developed in previous studies. For particle deposition model boundary conditions, it is assumed that the concentration of the particle is zero on the surface and the resuspension velocity is constant. However, the resuspension velocity may not be constant with the increase in mass of the deposited dust. To analyze the behavior of resuspension in air flow, a set of experiments were designed and conducted. Results showed that there was a linear relationship between the mass of resuspension and deposited dust. Also, the particle deposition model was improved by adding a resuspension item to the equation, and the steady-state equation was developed into a time-varying equation. The analysis results are presented in this paper.

  19. The impact of black carbon deposition on snowpack and streamflow in the Wasatch mountains in Utah: A study using MODIS albedo data, statistical modeling and machine learning

    Science.gov (United States)

    Panthail, Jai Kanth

    Salt Lake City, located at the base of the Wasatch mountain range in Utah, receives a majority of its potable water from a system of mountain creeks. Snowmelt runoff from mountain watersheds provides the city a clean and relatively inexpensive water supply, and has been a key driver in the city's growth and prosperity. There has been keen interest recently on the possible impact of the deposition of darkening matter, such as dust and black carbon (BC) on the snow, which might lead to a decrease in its 'albedo' or reflective capacity. Such a decrease is expected to result in faster melting of the snow, shifting springtime streamflows to winter. This study aimed to develop a modeling framework to estimate the impact on snowmelt-driven runoff due to various BC deposition scenarios. An albedo simulation model, Snow, Ice, and Aerosol Radiation (SNICAR) model, was used to understand the evolution of albedo under different BC loadings. An Albedo-Snow Water Equivalent (A-SWE) model was developed using a machine learning technique, 'Random Forests', to quantify the effect on the state of snowpack under various albedo-change scenarios. An Albedo-Snow Water Equivalent-Streamflow (A-SWE-S) model was designed using an advanced statistical modeling technique, 'Generalized Additive Models (GAMs)', to extend the analysis to streamflow variations. All models were tested and validated using robust k-fold cross-validation. Albedo data were obtained from NASA's MODIS satellite platform. The key results found the snowpack to be depleted 2-3 weeks later with an albedo increase between 5-10% above current conditions, and 1-2 weeks earlier under albedo decrease of 5-10% below current conditions. Future work will involve improving the A-SWE-S model by better accounting for lagged effects, and the use of results from both models in a city-wide systems model to understand water supply reliability under combined deposition and climate change scenarios.

  20. Examining Asphaltene Solubility on Deposition in Model Porous Media.

    Science.gov (United States)

    Lin, Yu-Jiun; He, Peng; Tavakkoli, Mohammad; Mathew, Nevin Thunduvila; Fatt, Yap Yit; Chai, John C; Goharzadeh, Afshin; Vargas, Francisco M; Biswal, Sibani Lisa

    2016-08-30

    Asphaltenes are known to cause severe flow assurance problems in the near-wellbore region of oil reservoirs. Understanding the mechanism of asphaltene deposition in porous media is of great significance for the development of accurate numerical simulators and effective chemical remediation treatments. Here, we present a study of the dynamics of asphaltene deposition in porous media using microfluidic devices. A model oil containing 5 wt % dissolved asphaltenes was mixed with n-heptane, a known asphaltene precipitant, and flowed through a representative porous media microfluidic chip. Asphaltene deposition was recorded and analyzed as a function of solubility, which was directly correlated to particle size and Péclet number. In particular, pore-scale visualization and velocity profiles, as well as three stages of deposition, were identified and examined to determine the important convection-diffusion effects on deposition.

  1. Modeling free convective gravitational effects in chemical vapor deposition

    Science.gov (United States)

    Stinespring, C. D.; Annen, K. D.

    1987-01-01

    In this paper, a combined fluid-mechanics, mass-transport, and chemistry model describing CVD in an open-tube atmospheric-pressure flow reactor is developed. The model allows gas-phase reactions to proceed to equilibrium and accounts for finite reaction rates at the surface of the deposition substrate. This model is a useful intermediate step toward a model employing fully rate-limited chemistry. The model is used to predict the effects of free convection on flow patterns, temperature and species-concentration profiles, and local deposition rates for silicon deposited by silane pyrolysis. These results are discussed in terms of implications for CVD of silicon and other compounds, microgravity studies, and techniques for testing and validating the model.

  2. A geostatical model for USA uranium deposits

    International Nuclear Information System (INIS)

    Drew, M.W.

    1979-01-01

    Evidence exists which suggests that the frequency distributions of both grade and size of metal deposits may be well approximated by lognormal distribution functions. Using data on presently viable deposits and a simplified function which links production cost to deposit grade and size, a bivariate lognormal deposit grade/size distribution may be calibrated for a given geological environment. Exploration is introduced by assuming that the proportion discovered of the potential uranium reserve available at or below a given production can be represented by a fraction of the average deposit size and the limit exploration expenditure. As output, the model derives estimates of total reserves linked to maximum production costs and to exploration expenditure where the latter may be expressed either as expenditure per lb of mineral discovered or as a given percentage of operating profit. Reserve/price functions have been derived for the USA based on USAEC data. Tentative conclusions which may be drawn from the results are: (1) Assuming that a similar proportion of profits continues to be allocated to exploration in the future, then the USA should be able to meet its own national demand for uranium up to the end of the century (say 2 M tons U) at prices up to US$35/lb U 3 O 8 (1.1.75$ values). (2) If instead of all exploration being funded from a fixed maximum proportion of mining company profits, consumers were to fund additional exploration separately, then it is possible that the total unit cost of uranium to the consumers would thereby be reduced. It should be stressed that these conclusions are tentative and are only as reliable as the input data and assumptions of the model. In particular no account is taken of commercial or political forces which could artificially restrict supplies or raise prices. The model should be regarded as a first attempt and is offered as a basis for discussion leading to further development. (author)

  3. Theoretical modelling of carbon deposition processes

    International Nuclear Information System (INIS)

    Marsh, G.R.; Norfolk, D.J.; Skinner, R.F.

    1985-01-01

    Work based on capsule experiments in the BNL Gamma Facility, aimed at elucidating the chemistry involved in the formation of carbonaceous deposit on CAGR fuel pin surfaces is described. Using a data-base derived from capsule experiments together with literature values for the kinetics of the fundamental reactions, a chemical model of the gas-phase processes has been developed. This model successfully reproduces the capsule results, whilst preliminary application to the WAGR coolant circuit indicates the likely concentration profiles of various radical species within the fuel channels. (author)

  4. Energy deposition model for I-125 photon radiation in water

    Energy Technology Data Exchange (ETDEWEB)

    Fuss, M.C.; Garcia, G. [Instituto de Fisica Fundamental, Consejo Superior de Investigaciones Cientificas (CSIC), Madrid (Spain); Munoz, A.; Oller, J.C. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Madrid (Spain); Blanco, F. [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid (Spain); Limao-Vieira, P. [Laboratorio de Colisoes Atomicas e Moleculares, Departamento de Fisica, CEFITEC, FCT-Universidade Nova de Lisboa, Caparica (Portugal); Williart, A.; Garcia, G. [Departamento de Fisica de los Materiales, Universidad Nacional de Educacion a Distancia, Madrid (Spain); Huerga, C.; Tellez, M. [Hospital Universitario La Paz, Madrid (Spain)

    2010-10-15

    In this study, an electron-tracking Monte Carlo algorithm developed by us is combined with established photon transport models in order to simulate all primary and secondary particle interactions in water for incident photon radiation. As input parameters for secondary electron interactions, electron scattering cross sections by water molecules and experimental energy loss spectra are used. With this simulation, the resulting energy deposition can be modelled at the molecular level, yielding detailed information about localization and type of single collision events. The experimental emission spectrum of I-125 seeds, as used for radiotherapy of different tumours, was used for studying the energy deposition in water when irradiating with this radionuclide. (authors)

  5. Energy deposition model for I-125 photon radiation in water

    International Nuclear Information System (INIS)

    Fuss, M.C.; Garcia, G.; Munoz, A.; Oller, J.C.; Blanco, F.; Limao-Vieira, P.; Williart, A.; Garcia, G.; Huerga, C.; Tellez, M.

    2010-01-01

    In this study, an electron-tracking Monte Carlo algorithm developed by us is combined with established photon transport models in order to simulate all primary and secondary particle interactions in water for incident photon radiation. As input parameters for secondary electron interactions, electron scattering cross sections by water molecules and experimental energy loss spectra are used. With this simulation, the resulting energy deposition can be modelled at the molecular level, yielding detailed information about localization and type of single collision events. The experimental emission spectrum of I-125 seeds, as used for radiotherapy of different tumours, was used for studying the energy deposition in water when irradiating with this radionuclide. (authors)

  6. Modelling of stomatal conductance and ozone deposition flux of Norway Spruce using deposition model

    Czech Academy of Sciences Publication Activity Database

    Zapletal, M.; Chroust, P.; Večeřa, Zbyněk; Mikuška, Pavel; Cudlín, Pavel; Urban, Otmar; Pokorný, Radek; Czerný, Radek; Janouš, Dalibor; Taufarová, Klára

    2009-01-01

    Roč. 12, 2-3 (2009), s. 75-81 ISSN 1335-339X R&D Projects: GA MŽP SP/1B7/189/07 Institutional research plan: CEZ:AV0Z60870520; CEZ:AV0Z40310501 Keywords : ozone concentration * ozone deposition * stomatal conductance * deposition velocity * resistance model * tropo-spheric ozone Subject RIV: DG - Athmosphere Sciences, Meteorology

  7. Surface growth of two kinds of particles deposition models

    International Nuclear Information System (INIS)

    Wei Wang; Cerdeira, H.A.

    1993-10-01

    The surface kinetics with diffusion of two kinds of particles (A and C) deposition models, randomlike and ballisticlike depositing on a (1 + 1)-dimensional substrate, has been studied in this paper. The scaling behaviour of the surface width for these two models is obtained for various deposition probability P of particle C (the probability of particle A, being 1 - P). We found that both models have a scaling behaviour: the surface width growth only depends on the time, W ∼ t α(p) for the early stage and W ∼ t β(P) for the intermediate time, as well as W ∼ L z for the later time with different exponents α(P) and β(P) and z for two models. In addition, there is a phase transition when the saturation surface widths are scaled to the deposition probability P for both models W(t = ∞) ∼ P γ : before and after the transition the scaling exponent γ is different. This transition is interpreted as that there are different morphologic structures when the depositing probability for one kind of particle, particle C, is larger than a critical value P c . (author). 16 refs, 5 figs, 2 tabs

  8. Data integration modeling applied to drill hole planning through semi-supervised learning: A case study from the Dalli Cu-Au porphyry deposit in the central Iran

    Science.gov (United States)

    Fatehi, Moslem; Asadi, Hooshang H.

    2017-04-01

    In this study, the application of a transductive support vector machine (TSVM), an innovative semi-supervised learning algorithm, has been proposed for mapping the potential drill targets at a detailed exploration stage. The semi-supervised learning method is a hybrid of supervised and unsupervised learning approach that simultaneously uses both training and non-training data to design a classifier. By using the TSVM algorithm, exploration layers at the Dalli porphyry Cu-Au deposit in the central Iran were integrated to locate the boundary of the Cu-Au mineralization for further drilling. By applying this algorithm on the non-training (unlabeled) and limited training (labeled) Dalli exploration data, the study area was classified in two domains of Cu-Au ore and waste. Then, the results were validated by the earlier block models created, using the available borehole and trench data. In addition to TSVM, the support vector machine (SVM) algorithm was also implemented on the study area for comparison. Thirty percent of the labeled exploration data was used to evaluate the performance of these two algorithms. The results revealed 87 percent correct recognition accuracy for the TSVM algorithm and 82 percent for the SVM algorithm. The deepest inclined borehole, recently drilled in the western part of the Dalli deposit, indicated that the boundary of Cu-Au mineralization, as identified by the TSVM algorithm, was only 15 m off from the actual boundary intersected by this borehole. According to the results of the TSVM algorithm, six new boreholes were suggested for further drilling at the Dalli deposit. This study showed that the TSVM algorithm could be a useful tool for enhancing the mineralization zones and consequently, ensuring a more accurate drill hole planning.

  9. Deposition of intranasal glucocorticoids--preliminary study.

    Science.gov (United States)

    Rapiejko, Piotr; Sosnowski, Tomasz R; Sova, Jarosław; Jurkiewicz, Dariusz

    2015-01-01

    Intranasal glucocorticoids are the treatment of choice in the therapy of rhinitis. The differences in efficiency of particular medications proven by therapeutic index may result from differences in composition of particular formulations as well as from diverse deposition in nasal cavities. Intranasal formulations of glucocorticoids differ in volume of a single dose in addition to variety in density, viscosity and dispenser nozzle structure. The aim of this report was to analyze the deposition of most often used intranasal glucocorticoids in the nasal cavity and assessment of the usefulness of a nose model from a 3D printer reflecting anatomical features of a concrete patient. Three newest and most often used in Poland intranasal glucocorticoids were chosen to analysis; mometasone furoate (MF), fluticasone propionate (FP) and fluticasone furoate (FF). Droplet size distribution obtained from the tested formulations was determined by use of a laser aerosol spectrometer Spraytec (Malvern Instruments, UK). The model of the nasal cavity was obtained using a 3D printer. The printout was based upon a tridimensional reconstruction of nasal cavity created on the basis of digital processing of computed tomography of paranasal sinuses. The deposition of examined medications was established by a method of visualization combined with image analysis using commercial substance which colored itself intensively under the influence of water being the dominant ingredient of all tested preparations. On the basis of obtained results regions of dominating deposition of droplets of intranasal medication on the wall and septum of the nasal cavity were compared. Droplet size of aerosol of tested intranasal medications typically lies within the range of 25-150 µm. All tested medications deposited mainly on the anterior part of inferior turbinate. FP preparation deposited also on the anterior part of the middle nasal turbinate, marginally embracing a fragment of the central part of this

  10. A predictive model for dimensional errors in fused deposition modeling

    DEFF Research Database (Denmark)

    Stolfi, A.

    2015-01-01

    This work concerns the effect of deposition angle (a) and layer thickness (L) on the dimensional performance of FDM parts using a predictive model based on the geometrical description of the FDM filament profile. An experimental validation over the whole a range from 0° to 177° at 3° steps and two...... values of L (0.254 mm, 0.330 mm) was produced by comparing predicted values with external face-to-face measurements. After removing outliers, the results show that the developed two-parameter model can serve as tool for modeling the FDM dimensional behavior in a wide range of deposition angles....

  11. EPR studies of a red wine bottle deposit, and the precipitates from a 'model' wine , and a white wine, both artificially aged

    International Nuclear Information System (INIS)

    Mitri, M.

    2003-01-01

    Full text: A red wine waxy bottle deposit is known to be an anthocyanin-protein compound. The EPR signal shows the presence of a free radical signal, and a Cu(2+) signal with N superhyperfme structure. Subsequently, EPR study of a model wine, catechin being the only phenol, showed a Cu(2+) signal and a free radical signal. The precipitate thrown by the model wine after artificial aging for 3 months at 45C showed a Cu(2+) signal of different bonding, and a free radical signal. All the previously mentioned Cu(2+) signals showed (differing) hyperfine structures. The precipitate thrown by a similarly artificially aged Chardonnay showed a free radical signal, and a Cu(2+) signal without hyperfine structure: no Cu(2+) signal was detected in the mother liquor. The Cu(2+) bonding in each case will be discussed

  12. A predictive model for dimensional errors in fused deposition modeling

    DEFF Research Database (Denmark)

    Stolfi, A.

    2015-01-01

    values of L (0.254 mm, 0.330 mm) was produced by comparing predicted values with external face-to-face measurements. After removing outliers, the results show that the developed two-parameter model can serve as tool for modeling the FDM dimensional behavior in a wide range of deposition angles....

  13. 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.

  14. Multiwalled Carbon Nanotube Deposition on Model Environmental Surfaces

    Science.gov (United States)

    Deposition of multiwalled carbon nanotubes (MWNTs) on model environmental surfaces was investigated using a quartz crystal microbalance with dissipation monitoring (QCM-D). Deposition behaviors of MWNTs on positively and negatively charged surfaces were in good agreement with Der...

  15. A new simulation model for electrochemical metal deposition

    International Nuclear Information System (INIS)

    Schmickler, W.; Poetting, K.; Mariscal, M.

    2006-01-01

    A new atomistic simulation model for electrochemical systems is presented. It combines microcanonical molecular dynamics for the electrode with stochastic dynamics for the solution, and allows the simulation of electrochemical deposition and dissolution for specific electrode potentials. As first applications the deposition of silver and platinum on Au(1 1 1) have been studied; both flat surfaces and surfaces with islands have been considered. The two systems behave quite differently: Ag on Au(1 1 1) grows layer by layer, while Pt forms a surface alloy on Au(1 1 1), which is followed by three-dimensional growth

  16. Delineating the structural controls on iron oxide-Cu-Au deposit genesis through implicit modeling: A case study from the E1 Group, Cloncurry 3 District, Australia

    OpenAIRE

    Case, George; Blenkinsop, Thomas; Chang, Zhaoshan; Huizenga, Jan Marten; Lilly, Richard; McLellan, John

    2017-01-01

    Iron oxide–Cu–Au (IOCG) deposits encompass a range of ore body shapes, including strata-bound replacement ores and hydrothermal breccias. We use the implicit method to make a detailed three-dimensional geological model of a strata-bound IOCG in the Cloncurry District, the E1 Group, to elucidate structural controls on mineralization. This model is compared with the nearby, world-class, Ernest Henry breccia-hosted IOCG deposit. Cu–Au mineralization in the E1 Group occurs as structurally control...

  17. Understanding error generation in fused deposition modeling

    International Nuclear Information System (INIS)

    Bochmann, Lennart; Transchel, Robert; Wegener, Konrad; Bayley, Cindy; Helu, Moneer; Dornfeld, David

    2015-01-01

    Additive manufacturing offers completely new possibilities for the manufacturing of parts. The advantages of flexibility and convenience of additive manufacturing have had a significant impact on many industries, and optimizing part quality is crucial for expanding its utilization. This research aims to determine the sources of imprecision in fused deposition modeling (FDM). Process errors in terms of surface quality, accuracy and precision are identified and quantified, and an error-budget approach is used to characterize errors of the machine tool. It was determined that accuracy and precision in the y direction (0.08–0.30 mm) are generally greater than in the x direction (0.12–0.62 mm) and the z direction (0.21–0.57 mm). Furthermore, accuracy and precision tend to decrease at increasing axis positions. The results of this work can be used to identify possible process improvements in the design and control of FDM technology. (paper)

  18. Understanding error generation in fused deposition modeling

    Science.gov (United States)

    Bochmann, Lennart; Bayley, Cindy; Helu, Moneer; Transchel, Robert; Wegener, Konrad; Dornfeld, David

    2015-03-01

    Additive manufacturing offers completely new possibilities for the manufacturing of parts. The advantages of flexibility and convenience of additive manufacturing have had a significant impact on many industries, and optimizing part quality is crucial for expanding its utilization. This research aims to determine the sources of imprecision in fused deposition modeling (FDM). Process errors in terms of surface quality, accuracy and precision are identified and quantified, and an error-budget approach is used to characterize errors of the machine tool. It was determined that accuracy and precision in the y direction (0.08-0.30 mm) are generally greater than in the x direction (0.12-0.62 mm) and the z direction (0.21-0.57 mm). Furthermore, accuracy and precision tend to decrease at increasing axis positions. The results of this work can be used to identify possible process improvements in the design and control of FDM technology.

  19. Carbonate rock depositional models: A microfacies approach

    Energy Technology Data Exchange (ETDEWEB)

    Carozzi, A.V.

    1988-01-01

    Carbonate rocks contain more than 50% by weight carbonate minerals such as calcite, dolomite, and siderite. Understanding how these rocks form can lead to more efficient methods of petroleum exploration. Micofacies analysis techniques can be used as a method of predicting models of sedimentation for carbonate rocks. Micofacies in carbonate rocks can be seen clearly only in thin sections under a microscope. This section analysis of carbonate rocks is a tool that can be used to understand depositional environments, diagenetic evolution of carbonate rocks, and the formation of porosity and permeability in carbonate rocks. The use of micofacies analysis techniques is applied to understanding the origin and formation of carbonate ramps, carbonate platforms, and carbonate slopes and basins. This book will be of interest to students and professionals concerned with the disciplines of sedimentary petrology, sedimentology, petroleum geology, and palentology.

  20. Overview of mercury dry deposition, litterfall, and throughfall studies

    Directory of Open Access Journals (Sweden)

    L. P. Wright

    2016-10-01

    Full Text Available The current knowledge concerning mercury dry deposition is reviewed, including dry-deposition algorithms used in chemical transport models (CTMs and at monitoring sites and related deposition calculations, measurement methods and studies for quantifying dry deposition of gaseous oxidized mercury (GOM and particulate bound mercury (PBM, and measurement studies of litterfall and throughfall mercury. Measured median GOM plus PBM dry deposition in Asia (10.7 µg m−2 yr−1 is almost double that in North America (6.1 µg m−2 yr−1 due to the higher anthropogenic emissions in Asia. The measured mean GOM plus PBM dry deposition in Asia (22.7 µg m−2 yr−1, however, is less than that in North America (30.8 µg m−2 yr−1. The variations between the median and mean values reflect the influences that single extreme measurements can have on the mean of a data set. Measured median litterfall and throughfall mercury are, respectively, 34.8 and 49.0 µg m−2 yr−1 in Asia, 12.8 and 16.3 µg m−2 yr−1 in Europe, and 11.9 and 7.0 µg m−2 yr−1 in North America. The corresponding measured mean litterfall and throughfall mercury are, respectively, 42.8 and 43.5 µg m−2 yr−1 in Asia, 14.2 and 19.0 µg m−2 yr−1 in Europe, and 12.9 and 9.3 µg m−2 yr−1 in North America. The much higher litterfall mercury than GOM plus PBM dry deposition suggests the important contribution of gaseous elemental mercy (GEM to mercury dry deposition to vegetated canopies. Over all the regions, including the Amazon, dry deposition, estimated as the sum of litterfall and throughfall minus open-field wet deposition, is more dominant than wet deposition for Hg deposition. Regardless of the measurement or modelling method used, a factor of 2 or larger uncertainties in GOM plus PBM dry deposition need to be kept in mind when using these numbers for mercury impact studies.

  1. COMPARING OF DEPOSIT MODEL AND LIFE INSURANCE MODEL IN MACEDONIA

    Directory of Open Access Journals (Sweden)

    TATJANA ATANASOVA-PACHEMSKA

    2016-02-01

    Full Text Available In conditions of the continuous decline of the interest rates for bank deposits, and at a time when uncertainty about the future is increasing, physical and legal persons have doubts how to secure their future or how and where to invest their funds and thus to “fertilize” and increase their savings. Individuals usually choose to put their savings in the bank for a certain period, and for that period to receive certain interest, or decide to invest their savings in different types of life insurance and thus to "take care" of their life, their future and the future of their families. In mathematics are developed many models that relate to the compounding and the insurance. This paper is a comparison of the deposit model and the model of life insurance

  2. Calcium pyrophosphate crystal deposition: the effect of soluble iron in a kinetic study using a gelatin matrix model.

    Science.gov (United States)

    Mandel, G S; Halverson, P B; Mandel, N S

    1988-06-01

    The kinetics of calcium pyrophosphate dihydrate (CPPD) crystal growth was studied by allowing calcium and pyrophosphate (PPi-4) ions to diffuse through a denatured collagen matrix (biological grade gelatin) in the presence of either ferric or ferrous ions. Ferric and, to some extent, ferrous ions blocked the migration of the PPi-4 diffusion gradient. This retardation in the [PPi-4] gradient led to numerous changes in the patterns of CPPD crystal formation. At the initial stages of crystal growth, the iron ions induced more crystal growth compared to control. At later incubation times, ferrous and ferric ions enhanced crystal growth at the expense of crystal nucleation. The presence of both ferrous and ferric ions resulted in the more rapid formation of the two crystals observed in vivo, triclinic CPPD and monoclinic CPPD. Further, both ferrous and ferric ions also reduced the solubility of the crystalline material in the broad diffuse band which formed when the Ca+2 and PPi-4 gradients first met. In this system, the presence of either ferrous or ferric ions increased the amount of hydroxyproline included in the crystalline precipitates. Iron was also incorporated into the crystals, particularly into the triclinic CPPD and monoclinic CPPD crystals.

  3. MIDDLE MIOCENE DEPOSITIONAL MODEL IN THE DRAVA DEPRESSION DESCRIBED BY GEOSTATISTICAL POROSITY AND THICKNESS MAPS (CASE STUDY: STARI GRADAC-BARCS NYUGAT FIELD

    Directory of Open Access Journals (Sweden)

    Tomislav Malvić

    2006-12-01

    Full Text Available Neogene depositional environments in the Drava depression can be classified in two groups. One group is of local alluvial fans, which were active during the period of Middle Miocene (Badenian extension through the entire Pannonian Basin. The second group is represented by continuous Pannonian and Pontian sedimentation starting with lacustrine environment of partly deep water and partly prodelta (turbidity fans and terminating at the delta plain sedimentation. The coarse-grained sediments of alluvial fans have the great hydrocarbon potential, because they often comprise reservoir rocks. Reservoir deposits are mostly overlain (as result of fan migration by pelitic seal deposits and sometimes including organic rich source facies. That Badenian sequences are often characterised by complete petroleum systems, what is confirmed by large number of oil and gas discoveries in such sediments in the Drava and other Croatian depressions. Alluvial environments are characterised by frequent changes of petrophysical properties, due to local character of depositional mechanism and material sources. In the presented paper, Stari Gradac-Barcs Nyugat field is selected as a case study for demonstrating the above mentioned heterogenic features of the Badenian sequences. Structural solutions are compared by maps of parameters related to depositional environment, i.e. porosity and thickness maps. Geostatistics were used for spatial extension of input dataset. The spatial variability of porosity values, i.e. reservoir quality, is interpreted by transition among different sub-environments (facies in the alluvial fan system.

  4. Application of natural analog studies to exploration for ore deposits

    International Nuclear Information System (INIS)

    Gustafson, D.L.

    1995-01-01

    Natural analogs are viewed as similarities in nature and are routinely utilized by exploration geologists in their search for economic mineral deposits. Ore deposit modeling is undertaken by geologists to direct their exploration activities toward favorable geologic environments and, therefore, successful programs. Two types of modeling are presented: (i) empirical model development based on the study of known ore deposit characteristics, and (ii) concept model development based on theoretical considerations and field observations that suggest a new deposit type, not known to exist in nature, may exist and justifies an exploration program. Key elements that are important in empirical model development are described, and examples of successful applications of these natural analogs to exploration are presented. A classical example of successful concept model development, the discovery of the McLaughlin gold mine in California, is presented. The utilization of natural analogs is an important facet of mineral exploration. Natural analogs guide explorationists in their search for new discoveries, increase the probability of success, and may decrease overall exploration expenditure

  5. A new approach for modeling dry deposition velocity of particles

    Science.gov (United States)

    Giardina, M.; Buffa, P.

    2018-05-01

    The dry deposition process is recognized as an important pathway among the various removal processes of pollutants in the atmosphere. In this field, there are several models reported in the literature useful to predict the dry deposition velocity of particles of different diameters but many of them are not capable of representing dry deposition phenomena for several categories of pollutants and deposition surfaces. Moreover, their applications is valid for specific conditions and if the data in that application meet all of the assumptions required of the data used to define the model. In this paper a new dry deposition velocity model based on an electrical analogy schema is proposed to overcome the above issues. The dry deposition velocity is evaluated by assuming that the resistances that affect the particle flux in the Quasi-Laminar Sub-layers can be combined to take into account local features of the mutual influence of inertial impact processes and the turbulent one. Comparisons with the experimental data from literature indicate that the proposed model allows to capture with good agreement the main dry deposition phenomena for the examined environmental conditions and deposition surfaces to be determined. The proposed approach could be easily implemented within atmospheric dispersion modeling codes and efficiently addressing different deposition surfaces for several particle pollution.

  6. Mathematical geology studies of deposit prospect types

    International Nuclear Information System (INIS)

    Liu Guangping

    1998-08-01

    Exact certainty prospect type of uranium deposit, not only can assure the quality of deposit prospects, but also increase economic benefits. Based on the standard of geological prospect of uranium deposit, the author introduces a method of Fuzzy Synthetical Comment for dividing prospect type of uranium deposit. The practical applications demonstrate that the regression accuracy, discriminated by Zadeh operator, of 15 known deposits is 100%

  7. Acute health effects of desktop 3D printing (fused deposition modeling) using acrylonitrile butadiene styrene and polylactic acid materials: An experimental exposure study in human volunteers.

    Science.gov (United States)

    Gümperlein, I; Fischer, E; Dietrich-Gümperlein, G; Karrasch, S; Nowak, D; Jörres, R A; Schierl, R

    2018-03-03

    3D printers are increasingly run at home. Nanoparticle emissions from those printers have been reported, which raises the question whether adverse health effects from ultrafine particles (UFP) can be elicited by 3D printers. We exposed 26 healthy adults in a single-blinded, randomized, cross-over design to emissions of a desktop 3D printer using fused deposition modeling (FDM) for 1 hour (high UFP-emitting acrylonitrile butadiene styrene [ABS] vs low-emitting polylactic acid [PLA]). Before and after exposures, cytokines (IL-1β, IL-6, TNF-α, INF-γ) and ECP in nasal secretions, exhaled nitric oxide (FeNO), urinary 8-isoprostaglandin F 2α (8-iso PGF 2α ), and self-reported symptoms were assessed. The exposures had no significant differential effect on 8-iso PGF 2α and nasal biomarkers. However, there was a difference (P printer emissions had no acute effect on inflammatory markers in nasal secretions and urine. The slight relative increase in FeNO after ABS printing compared to PLA might be due to eosinophilic inflammation from inhaled UFP particles. This possibility should be investigated in further studies using additional biomarkers and longer observation periods. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  8. Calcium pyrophosphate crystal deposition: the effect of monosodium urate and apatite crystals in a kinetic study using a gelatin matrix model.

    Science.gov (United States)

    Mandel, G S; Halverson, P B; Mandel, N S

    1988-06-01

    The kinetics of calcium pyrophosphate dihydrate (CPPD) crystal growth was studied by allowing calcium and pyrophosphate (PPi-4) ions to diffuse through a denatured collagen matrix (biological grade gelatin) in the presence of either monosodium urate monohydrate (MSU) or hydroxyapatite (HA) crystals. In this in vitro model system, MSU crystals significantly altered the kinetics of PPi-4 ionic diffusion through the gelatin matrix by allowing the [PPi-4] gradient to fall off much more rapidly, suggesting an increased level of scavenging of PPi-4 ions into crystalline materials. Even more significantly, the presence of MSU crystals markedly influenced the crystal growth morphology of triclinic CPPD, producing that observed in vivo. A large number of epitaxially dimensional matches between MSU and triclinic (t) and monoclinic (m) CPPD were identified, suggesting that MSU crystals can epitaxially induce CPPD crystal growth. This finding supports the hypothesis that the association of urate gout and CPPD crystal deposition disease is based on the nucleating potential of MSU crystals for CPPD crystal growth. In contrast, the HA crystal structure did not appear to serve as a nucleating agent for CPPD crystals. However, HA crystals did serve as effective traps for PPi-4 ions and their presence led to more stable CPPD crystal growth.

  9. Modelling atmospheric deposition flux of Cadmium and Lead in urban areas

    International Nuclear Information System (INIS)

    Cherin, Nicolas

    2017-01-01

    According to WHO, air pollution is responsible for more than 3.7 million premature deaths each year (OMS, 2014). Moreover, among these deaths, more than 70 within urban areas. Consequently, the health and environmental impacts of pollutants within these urban areas are of great concern in air quality studies. The deposition fluxes of air pollutants, which can be significant near sources of pollution, have rarely been modeled within urban areas. Historically, atmospheric deposition studies have focused mostly on remote areas to assess the potential impacts on ecosystems of acid deposition and nitrogen loading. Therefore, current atmospheric deposition models may not be suitable to simulate deposition fluxes in urban areas, which include complex surface geometries and diverse land use types. Atmospheric dry deposition is typically modeled 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 parameterize 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 parameterization of turbulence within the canopy, and a description of the urban canopy via key parameters to provide spatially distributed dry deposition fluxes. This approach provides spatially distributed dry deposition fluxes depending on surfaces (streets, walls, roofs) and flow regimes (recirculation and ventilation) within the urban area. (author) [fr

  10. A discussion of remote sensing geologic image model of a uranium deposit

    International Nuclear Information System (INIS)

    Qiao Rui

    1998-12-01

    Based on the geologic study on the uranium deposit, the items about remote sensing images of the mineral deposit were discussed, such as the best choice of temporal, the best compose of band, the image characteristics and image model. It is considered that the mineral deposit was controlled by the line, ring and arc through the interpretation of color-composite images. The geologic image model of the mineral deposit is annular fault block controlled by northeast and northwest structures. It is recommended that much attentions should be paid to mineralized regions being similar with this image model in long-range forecast

  11. A New Occurrence Model for National Assessment of Undiscovered Volcanogenic Massive Sulfide Deposits

    Science.gov (United States)

    Shanks, W.C. Pat; Dusel-Bacon, Cynthia; Koski, Randolph; Morgan, Lisa A.; Mosier, Dan; Piatak, Nadine M.; Ridley, Ian; Seal, Robert R.; Schulz, Klaus J.; Slack, John F.; Thurston, Roland

    2009-01-01

    Volcanogenic massive sulfide (VMS) deposits are very significant current and historical resources of Cu-Pb-Zn-Au-Ag, are active exploration targets in several areas of the United States and potentially have significant environmental effects. This new USGS VMS deposit model provides a comprehensive review of deposit occurrence and ore genesis, and fully integrates recent advances in the understanding of active seafloor VMS-forming environments, and integrates consideration of geoenvironmental consequences of mining VMS deposits. Because VMS deposits exhibit a broad range of geological and geochemical characteristics, a suitable classification system is required to incorporate these variations into the mineral deposit model. We classify VMS deposits based on compositional variations in volcanic and sedimentary host rocks. The advantage of the classification method is that it provides a closer linkage between tectonic setting and lithostratigraphic assemblages, and an increased predictive capability during field-based studies.

  12. Development of a Parafin Wax deposition Unit for Fused Deposition Modelling (FDM)

    OpenAIRE

    D'Angelo, Greta; Hansen, Hans Nørgaard; Pedersen, David Bue

    2014-01-01

    During the last decade Additive Manufacturing (AM) witnessed a big development in terms of technologies, processes and possibilities. However of materials and their use still represents a big challenge. In fact availability of materials is rather limited if compared to conventional manufacturing. This project illustrates the redesign of an extrusion unit for the deposition of paraffin wax in Fused Deposition Modelling (FDM) instead of the conventional polymeric materials. Among the benefits a...

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

    NARCIS (Netherlands)

    Zhou, Putian; Ganzeveld, Laurens; Rannik, Ullar; 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

  14. A stochastic model for colloid transport and deposition.

    Science.gov (United States)

    Bradford, S A; Toride, N

    2007-01-01

    Profiles of retained colloids in porous media have frequently been observed to be hyper-exponential or non-monotonic with transport depth under unfavorable attachment conditions, whereas filtration theory predicts an exponential profile. In this work we present a stochastic model for colloid transport and deposition that allows various hypotheses for such deviations to be tested. The model is based on the conventional advective dispersion equation that accounts for first-order kinetic deposition and release of colloids. One or two stochastic parameters can be considered in this model, including the deposition coefficient, the release coefficient, and the average pore water velocity. In the case of one stochastic parameter, the probability density function (PDF) is characterized using log-normal, bimodal log-normal, or a simple two species/region formulation. When two stochastic parameters are considered, then a joint log-normal PDF is employed. Simulation results indicated that variations in the deposition coefficient and the average pore water velocity can both produce hyper-exponential deposition profiles. Bimodal formulations for the PDF were also able to produce hyper-exponential profiles, but with much lower variances in the deposition coefficient. The shape of the deposition profile was found to be very sensitive to the correlation of deposition and release coefficients, and to the correlation of pore water velocity and deposition coefficient. Application of the developed stochastic model to a particular set of colloid transport and deposition data indicated that chemical heterogeneity of the colloid population could not fully explain the observed behavior. Alternative interpretations were therefore proposed based on variability of the pore size and the water velocity distributions.

  15. Polymer Matrix Composites using Fused Deposition Modeling Technology Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Fused deposition modeling (FDM) is an additive manufacturing technology that allows fabrication of complex three-dimensional geometries layer-by-layer. The goal of...

  16. Modeling and mapping of atmospheric mercury deposition in adirondack park, new york.

    Science.gov (United States)

    Yu, Xue; Driscoll, Charles T; Huang, Jiaoyan; Holsen, Thomas M; Blackwell, Bradley D

    2013-01-01

    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).

  17. Development of a distributed air pollutant dry deposition modeling framework

    International Nuclear Information System (INIS)

    Hirabayashi, Satoshi; Kroll, Charles N.; Nowak, David J.

    2012-01-01

    A distributed air pollutant dry deposition modeling system was developed with a geographic information system (GIS) to enhance the functionality of i-Tree Eco (i-Tree, 2011). With the developed system, temperature, leaf area index (LAI) and air pollutant concentration in a spatially distributed form can be estimated, and based on these and other input variables, dry deposition of carbon monoxide (CO), nitrogen dioxide (NO 2 ), sulfur dioxide (SO 2 ), and particulate matter less than 10 microns (PM10) to trees can be spatially quantified. Employing nationally available road network, traffic volume, air pollutant emission/measurement and meteorological data, the developed system provides a framework for the U.S. city managers to identify spatial patterns of urban forest and locate potential areas for future urban forest planting and protection to improve air quality. To exhibit the usability of the framework, a case study was performed for July and August of 2005 in Baltimore, MD. - Highlights: ► A distributed air pollutant dry deposition modeling system was developed. ► The developed system enhances the functionality of i-Tree Eco. ► The developed system employs nationally available input datasets. ► The developed system is transferable to any U.S. city. ► Future planting and protection spots were visually identified in a case study. - Employing nationally available datasets and a GIS, this study will provide urban forest managers in U.S. cities a framework to quantify and visualize urban forest structure and its air pollution removal effect.

  18. Deposition

    International Nuclear Information System (INIS)

    1984-01-01

    Monitoring of radionuclide contents in rainwater is a useful way to keep a check on any change in the external radiation dose caused by the deposited material. Thus analuses of 3 H, 89 Sr and 90 Sr as well as 137 Cs and other gamma radionuclide contents in deposition were continued both nationwide and in the vicinities of the nuclear power stations at Loviisa and Olkiluoto. The deposition of 90 Sr and 137 Cs was lower than in previous years, being only a small fraction of the highest deposition values measured in 1983. The tritium concentrations were also lower than in 1982. The total annual deposition of tritium at different sampling stations varied from 1.7 kBq/m 2 to 2.9 kBq/m 2

  19. Modelling topographic potential for erosion and deposition using GIS

    Science.gov (United States)

    Helena Mitasova; Louis R. Iverson

    1996-01-01

    Modelling of erosion and deposition in complex terrain within a geographical information system (GIS) requires a high resolution digital elevation model (DEM), reliable estimation of topographic parameters, and formulation of erosion models adequate for digital representation of spatially distributed parameters. Regularized spline with tension was integrated within a...

  20. An Evaluation of Ozone Dry Deposition in Global Scale Chemistry Climate Models

    Science.gov (United States)

    Hardacre, C.; Wild, O.; Emberson, L.

    2014-12-01

    Dry deposition of atmospheric oxidants to the Earth's surface or vegetation is important as both a major removal pathway governing their atmospheric abundance and as a key input of oxidants and nutrients to sensitive vegetation surfaces. By linking the atmosphere and biosphere, dry deposition processes contribute to wider climate and Earth system feedbacks which need to be adequately quantified for a full understanding of Earth system responses. In addition, they have immediate policy-relevant implications for air quality, ecosystem health and crop productivity that need to be assessed on local, regional and global scales. In this study we use results from the recent Task Force on Hemispheric Transport of Air Pollution (HTAP) model intercomparison to explore how dry deposition of ozone varies across 15 current atmospheric chemistry and transport models. While most models take a similar, resistances-based approach to parameterising dry deposition, there are substantial differences across the models in the magnitude and variability of the annual and monthly ozone deposition fluxes which contribute to the differences in modelled surface ozone and in the global tropospheric ozone budget. We find that the range in global ozone deposition flux over the HTAP model ensemble spans about 30% with deposition to ocean, grass land and tropical forests being particularly variable. Further, we compare modelled dry deposition of ozone to measurements made at a variety of locations in Europe and North America, noting differences of up to a factor of two but no clear systematic bias over the sites examined. We extend this analysis by running sensitivity studies to determine the importance of key parameters in the ozone dry deposition process, including soil moisture and leaf area index. This study provides an important first step towards quantifying the uncertainty in ozone dry deposition and permitting a more thorough, observation-based evaluation of this important process.

  1. Podiform chromite deposits--database and grade and tonnage models

    Science.gov (United States)

    Mosier, Dan L.; Singer, Donald A.; Moring, Barry C.; Galloway, John P.

    2012-01-01

    Chromite ((Mg, Fe++)(Cr, Al, Fe+++)2O4) is the only source for the metallic element chromium, which is used in the metallurgical, chemical, and refractory industries. Podiform chromite deposits are small magmatic chromite bodies formed in the ultramafic section of an ophiolite complex in the oceanic crust. These deposits have been found in midoceanic ridge, off-ridge, and suprasubduction tectonic settings. Most podiform chromite deposits are found in dunite or peridotite near the contact of the cumulate and tectonite zones in ophiolites. We have identified 1,124 individual podiform chromite deposits, based on a 100-meter spatial rule, and have compiled them in a database. Of these, 619 deposits have been used to create three new grade and tonnage models for podiform chromite deposits. The major podiform chromite model has a median tonnage of 11,000 metric tons and a mean grade of 45 percent Cr2O3. The minor podiform chromite model has a median tonnage of 100 metric tons and a mean grade of 43 percent Cr2O3. The banded podiform chromite model has a median tonnage of 650 metric tons and a mean grade of 42 percent Cr2O3. Observed frequency distributions are also given for grades of rhodium, iridium, ruthenium, palladium, and platinum. In resource assessment applications, both major and minor podiform chromite models may be used for any ophiolite complex regardless of its tectonic setting or ophiolite zone. Expected sizes of undiscovered podiform chromite deposits, with respect to degree of deformation or ore-forming process, may determine which model is appropriate. The banded podiform chromite model may be applicable for ophiolites in both suprasubduction and midoceanic ridge settings.

  2. Variable fused deposition modelling - concept design and tool path generation

    OpenAIRE

    Brooks, Hadley Laurence

    2011-01-01

    Current Fused Deposition Modelling (FDM) techniques use fixed diameter nozzles to deposit a filament of plastic layer by layer. The consequence is that the same small nozzle, essential for fine details, is also used to fill in relatively large volumes. In practice a Pareto-optimal nozzle diameter is chosen that attempts to maximise resolution while minimising build time. This paper introduces a concept for adapting an additive manufacturing system, which exploits a variable diameter nozzle fo...

  3. Development of a Parafin Wax deposition Unit for Fused Deposition Modelling (FDM)

    DEFF Research Database (Denmark)

    D'Angelo, Greta; Hansen, Hans Nørgaard; Pedersen, David Bue

    2014-01-01

    . This project illustrates the redesign of an extrusion unit for the deposition of paraffin wax in Fused Deposition Modelling (FDM) instead of the conventional polymeric materials. Among the benefits and brought by the use of paraffin wax in such system are: the possibility to make highly complex and precise...... the technology and opening to new challenges. The design presented in this paper represents a step towards the development of a multi material deposition unit, able to selectively depose specific materials on demand in the same product, according to needs. In order to achieve that, waxes and respectivedesigns...... extruder principles of modularity and reconfigurability are also taken into account in order to ease up a subsequent integration with a more complex system....

  4. Numerical Modelling of Suspended Transport and Deposition of Highway Deposited Sediments

    DEFF Research Database (Denmark)

    Bentzen, Thomas Ruby; Larsen, Torben; Bach, Christine

    Good data for calibration and validation of numerical models are of high importance. In the natural environment data can be hard to archive and the stochastic nature have governing influence on the data archived. Hence for modelling of suspended transport and deposition of particles, originating...... from the highway surfaces, in highway detention ponds, four experiments are carried out. To simplify the complexity of a real pond and for easy control and measurement the sediment transports where carried out in two rectangular channels....

  5. RETADD: a Regional Trajectory And Diffusion-Deposition model

    Energy Technology Data Exchange (ETDEWEB)

    Begovich, C. L.; Murphy, B. D.; Nappo, Jr., C. J.

    1978-06-01

    The Regional Trajectory and Diffusion-Deposition Model (RETADD) is based upon a version of the National Oceanic and Atmospheric Administration Air Resources Laboratory's Regional-Continental Scale Transport, Diffusion, and Deposition Model. The FORTRAN IV computer model uses a trajectory analysis technique for estimating the transport and long-range diffusion of material emitted from a point source. The wind trajectory portion of the code uses observed upper air winds to compute the transport of the material. Ground level concentrations and depositions are computed by using the Gaussian plume equation for wind trajectories projected forward in time. Options are included to specify an upper bound for the mixed layer and a chemical decomposition rate for the effluent. The limitations to the technique are discussed, the equations and model are described, and listings of the program, input, and output are included.

  6. Magnetospheric ion deposition on Titan's ionosphere in hybrid model

    Science.gov (United States)

    Sillanpaa, I.; Johnson, R. E.; Crary, F. J.; Young, D. T.; Kallio, E. J.; Jarvinen, R.

    2010-12-01

    Hybrid modelling allows tracking ion particle in self-consist electromagnetic fields. Titan is a specific case where ion gyromotion plays a significant role in the interaction with the ambient plasma flow. We present hybrid simulation results from a medium-strength magnetospheric flow case. The water-group ions are shown to dominate the energy deposition by particles into Titan's ionosphere, while incident protons and pickup ions deposit about a total of a third of the water-group energy. Neutral collisions for the incident ions were taken into account via stopping cross sections. We show that Titan's neutral exosphere reduces the flux and energy deposit of especially lighter flow ions into Titan's atmosphere. Distribution of impacts and energy deposit by incident watergroup ions onto Titan's exobase.

  7. Nickel-cobalt laterites: a deposit model: Chapter H in Mineral deposit models for resource assessment

    Science.gov (United States)

    Marsh, Erin; Anderson, Eric J.; Gray, Floyd

    2013-01-01

    Nickel-cobalt (Ni-Co) laterite deposits are supergene enrichments of Ni±Co that form from intense chemical and mechanical weathering of ultramafic parent rocks. These regolith deposits typically form within 26 degrees of the equator, although there are a few exceptions. They form in active continental margins and stable cratonic settings. It takes as little as one million years for a laterite profile to develop. Three subtypes of Ni-Co laterite deposits are classified according to the dominant Ni-bearing mineralogy, which include hydrous magnesium (Mg)-silicate, smectite, and oxide. These minerals form in weathering horizons that begin with the unweathered protolith at the base, saprolite next, a smectite transition zone only in profiles where drainage is very poor, followed by limonite, and then capped with ferricrete at the top. The saprolite contains Ni-rich hydrous Mg-silicates, the Ni-rich clays occur in the transition horizon, and Ni-rich goethite occurs in the limonite. Although these subtypes of deposits are the more widely used terms for classification of Ni-Co laterite deposits, most deposits have economic concentrations of Ni in more than one horizon. Because of their complex mineralogy and heterogeneous concentrations, mining of these metallurgically complex deposits can be challenging. Deposits range in size from 2.5 to about 400 million tonnes, with Ni and Co grades of 0.66–2.4 percent (median 1.3) and 0.01–0.15 percent (median 0.08), respectively. Modern techniques of ore delineation and mineralogical identification are being developed to aid in streamlining the Ni-Co laterite mining process, and low-temperature and low-pressure ore processing techniques are being tested that will treat the entire weathered profile. There is evidence that the production of Ni and Co from laterites is more energy intensive than that of sulfide ores, reflecting the environmental impact of producing a Ni-Co laterite deposit. Tailings may include high levels of

  8. Thermal Modeling of Direct Digital Melt-Deposition Processes

    Science.gov (United States)

    Cooper, K. P.; Lambrakos, S. G.

    2011-02-01

    Additive manufacturing involves creating three-dimensional (3D) objects by depositing materials layer-by-layer. The freeform nature of the method permits the production of components with complex geometry. Deposition processes provide one more capability, which is the addition of multiple materials in a discrete manner to create "heterogeneous" objects with locally controlled composition and microstructure. The result is direct digital manufacturing (DDM) by which dissimilar materials are added voxel-by-voxel (a voxel is volumetric pixel) following a predetermined tool-path. A typical example is functionally gradient material such as a gear with a tough core and a wear-resistant surface. The inherent complexity of DDM processes is such that process modeling based on direct physics-based theory is difficult, especially due to a lack of temperature-dependent thermophysical properties and particularly when dealing with melt-deposition processes. In order to overcome this difficulty, an inverse problem approach is proposed for the development of thermal models that can represent multi-material, direct digital melt deposition. This approach is based on the construction of a numerical-algorithmic framework for modeling anisotropic diffusivity such as that which would occur during energy deposition within a heterogeneous workpiece. This framework consists of path-weighted integral formulations of heat diffusion according to spatial variations in material composition and requires consideration of parameter sensitivity issues.

  9. Geological modeling of a stratified deposit with CAD-Based solid model automation

    Directory of Open Access Journals (Sweden)

    Ayten Eser

    Full Text Available Abstract The planning stages of mining activities require many comprehensive and detailed analyses. Determining the correct orebody model is the first stage and one of the most important. Three-dimensional solid modeling is one of the significant methods that can examine the position and shape of the ore deposit. Although there are many different types of mining software for determining a solid model, many users try to build geological models in the computer without knowing how these software packages work. As researchers on the subject, we wanted to answer the question "How would we do it". For this purpose, a system was developed for generating solid models using data obtained from boreholes. Obtaining this model in an AutoCAD environment will be important for geologists and engineers. Developed programs were first tested with virtual borehole data belonging to a virtual deposit. Then the real borehole data of a cement raw material site were successfully applied. This article allows readers not only to see a clear example of the programming approach to layered deposits but also to produce more complicated software in this context. Our study serves as a window to understanding the geological modeling process.

  10. Solid Organic Deposition During Gas Injection Studies

    DEFF Research Database (Denmark)

    Dandekar, Abhijit Y.; Andersen, Simon Ivar; Stenby, Erling Halfdan

    2000-01-01

    was also evident as oil fractions expelled from the top to bottom of the PVT cell were observed to vary in density, molecular weight, as well as darkness of color. The change in stability of the oil samples before and after the contact with gas was analyzed using flocculation threshold titration....... The asphaltene content of the different oil samples were determined by the TP 143 method. The standard asphaltenes and the solid organic deposit recovered from the swelling tests were analyzed using FTIR, HPLC-SEC and H-1 NMR. The aim of these analyses is to reveal the molecular nature of the deposits formed...

  11. Alternate slicing and deposition strategies for fused deposition modelling of light curved parts

    OpenAIRE

    B. Huang; S. Singamneni

    2012-01-01

    Fused deposition modeling (FDM), as one of the additive manufacturing (AM) techniques, has been widely used in the manufacturing industry from the 1990s. It is relatively cheaper than other AM methods and there are other advantages such as being able to process a variety of other polymers. Currently, FDM is more likely to be suitable for direct production of the terminal-use parts, in some cases challenging traditional process such as injection molding. Research evidences indicate that change...

  12. Study on the classification of uranium deposits in China (Ⅱ)

    International Nuclear Information System (INIS)

    Tong Hangshou

    2014-01-01

    Study on the changes of the deposit classification remains one important part in uranium metallogenesis, and much attention has been paid by the uranium geologists. Study on the deposit classification in China from the introduction to the development has already experienced nearly 60 years and a large amount of information has been accumulated and need to summarize. Much attention has been paid on the study on the uranium deposit classification by the author since 1960's, more than 80 examples of uranium deposit classifications have been accumulated, in which about 50 examples are uranium deposit types schemes in China. much inspiration has been obtained. By summarizing and rethinking the study on the uranium deposit types in China, a brand-new classification scheme has been raised, which will be divided into two parts to discuss in brief, this paper is the first part. (author)

  13. Study on the classification of uranium deposits in China (Ⅰ)

    International Nuclear Information System (INIS)

    Tong Hangshou

    2014-01-01

    Study on the changes of the deposit classification remains one important part in uranium metallogenesis, and much attention has been paid by the uranium geologists. Study on the deposit classification in China from the introduction to the development has already experienced nearly 60 years and a large amount of information has been accumulated and need to summarize. Much attention has been paid on the study on the uranium deposit classification by the author since 1960's, more than 80 examples of uranium deposit classifications have been accumulated, in which about 50 examples are uranium deposit types schemes in China. much inspiration has been obtained. By summarizing and rethinking the study on the uranium deposit types in China, a brand-new classification scheme has been raised, which will be divided into two parts to discuss in brief, this paper is the first part. (author)

  14. Dust deposition: iron source or sink? A case study

    Directory of Open Access Journals (Sweden)

    Y. Ye

    2011-08-01

    Full Text Available A significant decrease of dissolved iron (DFe concentration has been observed after dust addition into mesocosms during the DUst experiment in a low Nutrient low chlorophyll Ecosystem (DUNE, carried out in the summer of 2008. Due to low biological productivity at the experiment site, biological consumption of iron can not explain the magnitude of DFe decrease. To understand processes regulating the observed DFe variation, we simulated the experiment using a one-dimensional model of the Fe biogeochemical cycle, coupled with a simple ecosystem model. Different size classes of particles and particle aggregation are taken into account to describe the particle dynamics. DFe concentration is regulated in the model by dissolution from dust particles and adsorption onto particle surfaces, biological uptake, and photochemical mobilisation of particulate iron.

    The model reproduces the observed DFe decrease after dust addition well. This is essentially explained by particle adsorption and particle aggregation that produces a high export within the first 24 h. The estimated particle adsorption rates range between the measured adsorption rates of soluble iron and those of colloidal iron, indicating both processes controlling the DFe removal during the experiment. A dissolution timescale of 3 days is used in the model, instead of an instantaneous dissolution, underlining the importance of dissolution kinetics on the short-term impact of dust deposition on seawater DFe.

    Sensitivity studies reveal that initial DFe concentration before dust addition was crucial for the net impact of dust addition on DFe during the DUNE experiment. Based on the balance between abiotic sinks and sources of DFe, a critical DFe concentration has been defined, above which dust deposition acts as a net sink of DFe, rather than a source. Taking into account the role of excess iron binding ligands and biotic processes, the critical DFe concentration might be applied to

  15. Predictive models for deposit accumulation and corrosion on secondary side of steam generators

    International Nuclear Information System (INIS)

    Choi, Samuel; Moroney, Velvet; Marks, Chuck; Kreider, Marc

    2012-09-01

    Experience demonstrates that deposit accumulation in steam generators (SGs) can lead to corrosion of tubes. To minimize the probability of this corrosion, utilities employ a variety of deposit control strategies. However, these processes can involve significant costs and potentially affect outage critical paths. Since there has been no model that quantifies tube degradation as a function of deposit accumulation, utilities have had to make decisions regarding deposit control strategies without a reliable quantitative basis. The objective of this study is to develop methods that utilities can use to quantify benefits of SG deposit control strategies with regard to rates of secondary-side tube corrosion. Two different methodologies are employed in this work. The first methodology is empirical and is involved an attempt to correlate degradation rates with deposit accumulation as indicated by sludge pile height. Because there has been relatively little tube degradation in currently operating steam generators, this correlation is developed using data for Alloy 600MA SG tubes. To increase the number of units that could be used for defect/deposit correlations, a method to relate the sludge pile deposit mass and the number of tubes with non-zero sludge height is developed. The second methodology is theoretical and is based on the use of calculated differences in temperature and chemistry to predict the effect of deposits on corrosion rates. Computational fluid dynamics (CFD) models are developed to simulate thermal-hydraulic conditions representative of conditions that are present within porous deposits formed at the top of tube sheet. This paper will discuss the development and application of the predictive models for deposit accumulation and corrosion on the secondary side of steam generators. (authors)

  16. Modeling airflow and particle transport/deposition in pulmonary airways.

    Science.gov (United States)

    Kleinstreuer, Clement; Zhang, Zhe; Li, Zheng

    2008-11-30

    A review of research papers is presented, pertinent to computer modeling of airflow as well as nano- and micron-size particle deposition in pulmonary airway replicas. The key modeling steps are outlined, including construction of suitable airway geometries, mathematical description of the air-particle transport phenomena and computer simulation of micron and nanoparticle depositions. Specifically, diffusion-dominated nanomaterial deposits on airway surfaces much more uniformly than micron particles of the same material. This may imply different toxicity effects. Due to impaction and secondary flows, micron particles tend to accumulate around the carinal ridges and to form "hot spots", i.e., locally high concentrations which may lead to tumor developments. Inhaled particles in the size range of 20nm< or =dp< or =3microm may readily reach the deeper lung region. Concerning inhaled therapeutic particles, optimal parameters for mechanical drug-aerosol targeting of predetermined lung areas can be computed, given representative pulmonary airways.

  17. Fused deposition modelling of sodium caseinate dispersions

    NARCIS (Netherlands)

    Schutyser, M.A.I.; Houlder, S.; Wit, de Martin; Buijsse, C.A.P.; Alting, A.C.

    2018-01-01

    Only recently, researchers have started experimenting with 3D printing of foods. The aim of this study was to investigate 3D printed objects from sodium caseinate dispersions, exhibiting reversible gelation behaviour. Gelation and dispensing behaviour were explored and structures of different

  18. 3D Modelling of Transport, Deposition and Resuspension of Highway Deposited Sediments in wet Detention Ponds

    DEFF Research Database (Denmark)

    Bentzen, Thomas Ruby

    2010-01-01

    concrete channel with width of 0.8m and a water depth of approximately 0.8m and in circular flume experiments in order to reproduce near-bed specific processes such as resuspension and consolidation. With a fairly good agreement with measurements, modelling of hydrodynamics, transport of dissolved...... pollutants and particles in wet detention ponds is possible with application of a three dimensional RANS model and the advection/dispersion equation taken physical phenomena like wind, waves, deposition, erosion and consolidation of the bottom sediment into account....

  19. Development of a distributed air pollutant dry deposition modeling framework

    Science.gov (United States)

    Satoshi Hirabayashi; Charles N. Kroll; David J. Nowak

    2012-01-01

    A distributed air pollutant dry deposition modeling systemwas developed with a geographic information system (GIS) to enhance the functionality of i-Tree Eco (i-Tree, 2011). With the developed system, temperature, leaf area index (LAI) and air pollutant concentration in a spatially distributed form can be estimated, and based on these and other input variables, dry...

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

    International Nuclear Information System (INIS)

    Brandt, J.; Christensen, J.H.; Frohn, L.M.; Frydendall, J.; Geels, C.; Hansen, K.M.

    2006-01-01

    Full text: 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 MM5v2 model is used as a meteorological driver. 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 137 Cs, 134 Cs and 131 I 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

  1. Modeling atmospheric nitrogen deposition and transport in the Chesapeake Bay watershed.

    Science.gov (United States)

    Sheeder, Scott A; Lynch, James A; Grimm, Jeffrey

    2002-01-01

    Atmospheric deposition of nitrate nitrogen and ammonium nitrogen has been identified as a major factor in the decline of water quality in the Chesapeake Bay. Reports have indicated that atmospheric deposition may account for 25 to 80% of the total nitrogen load entering the bay. However, uncertainties exist regarding the accuracy of the atmospheric deposition inputs, nitrogen retention coefficients, and in-stream nutrient uptake rates used in these studies. This project was designed to reassess the potential inputs of atmospheric nitrogen deposition to the bay through the use of a high-resolution wet deposition model, improved wet and dry deposition and nutrient retention estimates, existing soils and land use data, and geographic information systems software. Model results indicate that the methods used in previous studies may overestimate the contribution of atmospheric nitrate and ammonium deposition to the Chesapeake Bay watershed (CBW). Wet and dry atmospheric nitrate and ammonium nitrogen deposition estimates to the CBW ranged from 52.7 to 141.9 and 41.9 to 60.1 million kg/yr, respectively, between 1984 and 1996. Dry and total atmospheric deposition loads to the watershed are substantially less than previous estimates. Estimates of the percent contribution of atmospherically deposited nitrogen to the Chesapeake Bay represent between 20 and 32% of the total nitrate and ammonium nitrogen load to the watershed from all nitrogen sources. While these estimates are lower than many other published estimates, regression analysis of model parameters, nitrogen retention coefficients, output, and measured in-stream nitrogen loads indicate that the calculated nitrogen loads may still be too high.

  2. Linking nitrogen deposition to nitrate concentrations in groundwater below nature areas : modelling approach and data requirements

    NARCIS (Netherlands)

    Bonten, L.T.C.; Mol-Dijkstra, J.P.; Wieggers, H.J.J.; Vries, de W.; Pul, van W.A.J.; Hoek, van den K.W.

    2009-01-01

    This study determines the most suitable model and required model improvements to link atmospheric deposition of nitrogen and other elements in the Netherlands to measurements of nitrogen and other elements in the upper groundwater. The deterministic model SMARTml was found to be the most suitable

  3. Occurrence model for volcanogenic beryllium deposits: Chapter F in Mineral deposit models for resource assessment

    Science.gov (United States)

    Foley, Nora K.; Hofstra, Albert H.; Lindsey, David A.; Seal, Robert R.; Jaskula, Brian W.; Piatak, Nadine M.

    2012-01-01

    Current global and domestic mineral resources of beryllium (Be) for industrial uses are dominated by ores produced from deposits of the volcanogenic Be type. Beryllium deposits of this type can form where hydrothermal fluids interact with fluorine and lithophile-element (uranium, thorium, rubidium, lithium, beryllium, cesium, tantalum, rare earth elements, and tin) enriched volcanic rocks that contain a highly reactive lithic component, such as carbonate clasts. Volcanic and hypabyssal high-silica biotite-bearing topaz rhyolite constitutes the most well-recognized igneous suite associated with such Be deposits. The exemplar setting is an extensional tectonic environment, such as that characterized by the Basin and Range Province, where younger topaz-bearing igneous rock sequences overlie older dolomite, quartzite, shale, and limestone sequences. Mined deposits and related mineralized rocks at Spor Mountain, Utah, make up a unique economic deposit of volcanogenic Be having extensive production and proven and probable reserves. Proven reserves in Utah, as reported by the U.S. Geological Survey National Mineral Information Center, total about 15,900 tons of Be that are present in the mineral bertrandite (Be4Si2O7(OH)2). At the type locality for volcanogenic Be, Spor Mountain, the tuffaceous breccias and stratified tuffs that host the Be ore formed as a result of explosive volcanism that brought carbonate and other lithic fragments to the surface through vent structures that cut the underlying dolomitic Paleozoic sedimentary rock sequences. The tuffaceous sediments and lithic clasts are thought to make up phreatomagmatic base surge deposits. Hydrothermal fluids leached Be from volcanic glass in the tuff and redeposited the Be as bertrandite upon reaction of the hydrothermal fluid with carbonate clasts in lithic-rich sections of tuff. The localization of the deposits in tuff above fluorite-mineralized faults in carbonate rocks, together with isotopic evidence for the

  4. Solid Organic Deposition During Gas Injection Studies

    DEFF Research Database (Denmark)

    Dandekar, Abhijit Y.; Andersen, Simon Ivar; Stenby, Erling Halfdan

    2000-01-01

    was also evident as oil fractions expelled from the top to bottom of the PVT cell were observed to vary in density, molecular weight, as well as darkness of color. The change in stability of the oil samples before and after the contact with gas was analyzed using flocculation threshold titration......Recently a series of first contact miscibility (swelling) experiments have been performed on undersaturated light and heavy oils using LPG rich and methane rich injection gases, in which solid organic deposition was observed. A compositional gradient in the oils during the gas injection process...... during the gas injection process in comparison with the standard asphaltenes in order to understand the mechanisms involved in asphaltene deposition....

  5. Mechanistic study of aerosol dry deposition on vegetated canopies

    International Nuclear Information System (INIS)

    Petroff, A.

    2005-04-01

    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)

  6. 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

  7. Modeling of flame assisted chemical vapor deposition of silicon films

    Energy Technology Data Exchange (ETDEWEB)

    Masi, M.; Cavallotti, C.; Raffa, E. [Dipartimento di Chimica, Materiali e Ingegneria Chimica, Politecnico di Milano, via Mancinelli 7, 20131 Milano (Italy)

    2011-08-15

    The simulation of a flame assisted chemical vapor deposition (FACVD) process is here proposed with reference to the growth of silicon thin films through the silane/chlorosilanes/hydrogen/chlorine route. The goal is to design a reactor able to deposit micromorphous or multicrystalline films at the high growth rates necessary for photovoltaic applications. In fact, since FACVD processes can operate in atmospheric conditions and in auto-thermal mode, they present significant energetic advantages with respect to the plasma assisted technology used today. This work is in particular devoted to illustrate the multi-hierarchical modeling procedure adopted to determine the process optimal operating conditions and to design the deposition chamber. Different burner geometries (single, porous or multiple nozzles burner) were investigated in order to exploit the advantages of the two classical stagnation flow and Bunsen stretched flames. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. Modeling of thermophoretic deposition of aerosols in nuclear reactor containments

    International Nuclear Information System (INIS)

    Fernandes, A.; Loyalka, S.K.

    1996-01-01

    Aerosol released in postulated or real nuclear reactor accidents can deposit on containment surfaces via motion induced by temperature gradients in addition to the motion due to diffusion and gravity. The deposition due to temperature gradients is known as thermophoretic deposition, and it is currently modeled in codes such as CONTAIN in direct analogy with heat transfer, but there have been questions about such analogies. This paper focuses on a numerical solution of the particle continuity equation in laminar flow condition characteristics of natural convection. First, the thermophoretic deposition rate is calculated as a function of the Prandtl and Schmidt numbers, the thermophoretic coefficient K, and the temperature difference between the atmosphere and the wall. Then, the cases of diffusion alone and a boundary-layer approximation (due to Batchelor and Shen) to the full continuity equation are considered. It is noted that an analogy with heat transfer does not hold, but for the circumstances considered in this paper, the deposition rates from the diffusion solution and the boundary-layer approximation can be added to provide reasonably good agreement (maximum deviation 30%) with the full solution of the particle continuity equation. Finally, correlations useful for implementation in the reactor source term codes are provided

  9. A dynamic compartment model for assessing the transfer of radionuclide deposited onto flooded rice-fields

    International Nuclear Information System (INIS)

    Keum, Dong-Kwon; Lee, Han-Soo; Choi, Heui-Ju; Kang, Hee-Seok; Lim, Kwang-Muk; Choi, Young-Ho; Lee, Chang-Woo

    2004-01-01

    A dynamic compartment model has been studied to estimate the transfer of radionuclides deposited onto flooded rice-fields after an accidental release. In the model, a surface water compartment and a direct shoot-base absorption from the surface water to the rice-plant, which are major features discriminating the present model from the existing model, has been introduced to account for the flooded condition of rice-fields. The model has been applied to the deposition experiments of 137 Cs on rice-fields that were performed at three different times to simulate the deposition before transplanting (May 2) and during the growth of the rice (June 1 and August 12), respectively. In the case of the deposition of May 2, the root-uptake is the most predominant process for transferring 137 Cs to the rice-body and grain. When the radionuclide is applied just after transplanting (June 1), the activity of the body is controlled by the shoot-base absorption and the activity of the grain by the root-uptake. The deposition just before ear-emergence (August 12) shows that the shoot-base absorption contributes entirely to the increase of both the activities of the body and grain. The model prediction agrees within one or two factors with the experimental results obtained for a respective deposition experiment

  10. A fragment-cloud model for asteroid breakup and atmospheric energy deposition

    Science.gov (United States)

    Wheeler, Lorien F.; Register, Paul J.; Mathias, Donovan L.

    2017-10-01

    As asteroids break up during atmospheric entry, they deposit energy that can be seen in flares of light and, if substantial enough, can produce damaging blast waves. Analytic models of asteroid breakup and energy deposition processes are needed in order to assess potential airburst hazards, and to enable inferences about asteroid properties or breakup physics to be made from comparisons with observed meteors. This paper presents a fragment-cloud model (FCM) that is able to represent a broad range of breakup behaviors and the resulting variations in energy deposition in ways that make it a useful tool for both applications. Sensitivity studies are performed to investigate how variations the model's fragmentation parameters affect the energy deposition results for asteroids 20-500 m in diameter. The model is also used to match observational data from the Chelyabinsk meteor and infer potential asteroid properties and representative modeling parameter ranges. Results illustrate how the model's fragmentation parameters can introduce different energy deposition features, and how much they affect the overall energy deposition rates, magnitudes, and altitudes that would drive ground damage for risk assessment applications.

  11. Computational fluid dynamics modeling of Bacillus anthracis spore deposition in rabbit and human respiratory airways

    Energy Technology Data Exchange (ETDEWEB)

    Kabilan, S.; Suffield, S. R.; Recknagle, K. P.; Jacob, R. E.; Einstein, D. R.; Kuprat, A. P.; Carson, J. P.; Colby, S. M.; Saunders, J. H.; Hines, S. A.; Teeguarden, J. G.; Straub, T. M.; Moe, M.; Taft, S. C.; Corley, R. A.

    2016-09-01

    Three-dimensional computational fluid dynamics and Lagrangian particle deposition models were developed to compare the deposition of aerosolized Bacillus anthracis spores in the respiratory airways of a human with that of the rabbit, a species commonly used in the study of anthrax disease. The respiratory airway geometries for each species were derived respectively from computed tomography (CT) and µCT images. Both models encompassed airways that extended from the external nose to the lung with a total of 272 outlets in the human model and 2878 outlets in the rabbit model. All simulations of spore deposition were conducted under transient, inhalation–exhalation breathing conditions using average species-specific minute volumes. Two different exposure scenarios were modeled in the rabbit based upon experimental inhalation studies. For comparison, human simulations were conducted at the highest exposure concentration used during the rabbit experimental exposures. Results demonstrated that regional spore deposition patterns were sensitive to airway geometry and ventilation profiles. Due to the complex airway geometries in the rabbit nose, higher spore deposition efficiency was predicted in the nasal sinus compared to the human at the same air concentration of anthrax spores. In contrast, higher spore deposition was predicted in the lower conducting airways of the human compared to the rabbit lung due to differences in airway branching pattern. This information can be used to refine published and ongoing biokinetic models of inhalation anthrax spore exposures, which currently estimate deposited spore concentrations based solely upon exposure concentrations and inhaled doses that do not factor in species-specific anatomy and physiology for deposition.

  12. Subalpine Pyrenees received higher nitrogen deposition than predicted by EMEP and CHIMERE chemistry-transport models

    Science.gov (United States)

    Boutin, Marion; Lamaze, Thierry; Couvidat, Florian; Pornon, André

    2015-08-01

    Deposition of reactive nitrogen (N) from the atmosphere is expected to be the third greatest driver of biodiversity loss by the year 2100. Chemistry-transport models are essential tools to estimate spatially explicit N deposition but the reliability of their predictions remained to be validated in mountains. We measured N deposition and air concentration over the subalpine Pyrenees. N deposition was found to range from 797 to 1,463 mg N m-2 year-1. These values were higher than expected from model predictions, especially for nitrate, which exceeded the estimations of EMEP by a factor of 2.6 and CHIMERE by 3.6. Our observations also displayed a reversed reduced-to-oxidized ratio in N deposition compared with model predictions. The results highlight that the subalpine Pyrenees are exposed to higher levels of N deposition than expected according to standard predictions and that these levels exceed currently recognized critical loads for most high-elevation habitats. Our study reveals a need to improve the evaluation of N deposition in mountains which are home to a substantial and original part of the world’s biodiversity.

  13. Modeling transport and deposition of the Mekong River sediment

    Science.gov (United States)

    Xue, Zuo; He, Ruoying; Liu, J. Paul; Warner, John C.

    2012-01-01

    A Coupled Wave–Ocean–SedimentTransport Model was used to hindcast coastal circulation and fine sedimenttransport on the Mekong shelf in southeastern Asian in 2005. Comparisons with limited observations showed that the model simulation captured the regional patterns and temporal variability of surface wave, sea level, and suspended sediment concentration reasonably well. Significant seasonality in sedimenttransport was revealed. In summer, a large amount of fluvial sediments was delivered and deposited near the MekongRiver mouth. In the following winter, strong ocean mixing, and coastal current lead to resuspension and southwestward dispersal of a small fraction of previously deposited sediments. Model sensitivity experiments (with reduced physics) were performed to investigate the impact of tides, waves, and remotely forced ambient currents on the transport and dispersal of the fluvial sediment. Strong wave mixing and downwelling-favorable coastal current associated with the more energetic northeast monsoon in the winter season are the main factors controlling the southwestward along-shelf transport.

  14. Structural, electrical and optical studies on spray-deposited ...

    Indian Academy of Sciences (India)

    Structural, electrical and optical studies on spray-deposited ZnO. Table 1. Spray parameters for film deposition. Spray parameter. Value. Concentration of zinc acetate solution. 0.1 M. Nozzle–substrate ..... [13] F Paraguay, D M Miki-Yoshida, J Morales, J Solis and W Estrada, Thin Solid Films 373, 137. (2000). [14] B Baruwati ...

  15. Deposit model for heavy-mineral sands in coastal environments: Chapter L in Mineral deposit models for resource assessment

    Science.gov (United States)

    Van Gosen, Bradley S.; Fey, David L.; Shah, Anjana K.; Verplanck, Philip L.; Hoefen, Todd M.

    2014-01-01

    This report provides a descriptive model of heavy-mineral sands, which are sedimentary deposits of dense minerals that accumulate with sand, silt, and clay in coastal environments, locally forming economic concentrations of the heavy minerals. This deposit type is the main source of titanium feedstock for the titanium dioxide (TiO2) pigments industry, through recovery of the minerals ilmenite (Fe2+TiO3), rutile (TiO2), and leucoxene (an alteration product of ilmenite). Heavy-mineral sands are also the principal source of zircon (ZrSiO4) and its zirconium oxide; zircon is often recovered as a coproduct. Other heavy minerals produced as coproducts from some deposits are sillimanite/kyanite, staurolite, monazite, and garnet. Monazite [(Ce,La,Nd,Th)PO4] is a source of rare earth elements as well as thorium, which is used in thorium-based nuclear power under development in India and elsewhere.

  16. A fundamental study of fission product deposition on the wall surface

    International Nuclear Information System (INIS)

    Ishiguro, R.; Sakashita, H.; Sugiyama, K.

    1987-01-01

    Deposition of soluble matters on wall surfaces is studied in the present report for the purpose to understand a mechanism of fission product deposition on the wall surface in a molten salt reactor. Calcium carbonate solution is used to observe the fundamental mechanism of deposition. The experiments are performed under conditions of turbulent flow of the solution over a heated wall. According to the experimental results a model is proposed to estimate deposition rate. The model consists of two parts, one is the initial nucleus formation on a clean wall surface and the other is the constant increase of deposition succeeding to the first stage. The model is assessed by comparing it with the experimental results. Both results coincide well in some parameters, but not so well in others. (author)

  17. Reactive physical vapor deposition of TixAlyN: Integrated plasma-surface modeling characterization

    International Nuclear Information System (INIS)

    Zhang Da; Schaeffer, J.K.

    2004-01-01

    Reactive physical vapor deposition (RPVD) has been widely applied in the microelectronic industry for producing thin films. Fundamental understanding of RPVD mechanisms is needed for successful process development due to the high sensitivity of film properties on process conditions. An integrated plasma equipment-target nitridation modeling infrastructure for RPVD has therefore been developed to provide mechanistic insights and assist optimal process design. The target nitridation model computes target nitride coverage based on self-consistently derived plasma characteristics from the plasma equipment model; target sputter yields needed in the plasma equipment model are also self-consistently derived taking into account the yield-suppressing effect from nitridation. The integrated modeling infrastructure has been applied to investigating RPVD processing with a Ti 0.8 Al 0.2 compound target and an Ar/N 2 gas supply. It has been found that the process produces athermal metal neutrals as the primary deposition precursor. The metal stoichiometry in the deposited film is close to the target composition due to the predominance of athermal species in the flux that reaches the substrate. Correlations between process parameters (N 2 flow, target power), plasma characteristics, surface conditions, and deposition kinetics have been studied with the model. The deposition process is characterized by two regimes when the N 2 flow rate is varied. When N 2 is dilute relative to argon, target nitride coverage increases rapidly with increasing N 2 flow. The sputter yield and deposition rate consequently decrease. For less dilute N 2 mixtures, the sputter yield and deposition rate are stable due to the saturation of target nitridation. With increasing target power, the electron density increases nearly linearly while the variation of N generation is much smaller. Target nitridation and its suppression of the sputter yield saturate at high N 2 flow rendering these parameters

  18. Sediment-hosted gold deposits of the world: database and grade and tonnage models

    Science.gov (United States)

    Berger, Vladimir I.; Mosier, Dan L.; Bliss, James D.; Moring, Barry C.

    2014-01-01

    recommend using the appropriate grade and tonnage model presented in this study for mineral resource assessments depending on the geologic and mineralogical data available for a region. Tonnage and contained gold within the general sediment-hosted gold model are analyzed based on major geologic features such as tectonic setting and magmatic (dikes, sills, and stocks) or amagmatic environment. The results show a significant difference in tonnage and contained gold, with higher median values in deposits spatially associated with igneous rocks, regardless of structural style of the deposit. These results suggest that magmatic environments control mineralization intensity—an important consideration in the regional assessment of prospective areas for sediment-hosted gold deposits.

  19. Low-Volatility Model Demonstrates Humidity Affects Environmental Toxin Deposition on Plastics at a Molecular Level.

    Science.gov (United States)

    Hankett, Jeanne M; Collin, William R; Yang, Pei; Chen, Zhan; Duhaime, Melissa

    2016-02-02

    Despite the ever-increasing prevalence of plastic debris and endocrine disrupting toxins in aquatic ecosystems, few studies describe their interactions in freshwater environments. We present a model system to investigate the deposition/desorption behaviors of low-volatility lake ecosystem toxins on microplastics in situ and in real time. Molecular interactions of gas-phase nonylphenols (NPs) with the surfaces of two common plastics, poly(styrene) and poly(ethylene terephthalate), were studied using quartz crystal microbalance and sum frequency generation vibrational spectroscopy. NP point sources were generated under two model environments: plastic on land and plastic on a freshwater surface. We found the headspace above calm water provides an excellent environment for NP deposition and demonstrate significant NP deposition on plastic within minutes at relevant concentrations. Further, NP deposits and orders differently on both plastics under humid versus dry environments. We attributed the unique deposition behaviors to surface energy changes from increased water content during the humid deposition. Lastly, nanograms of NP remained on microplastic surfaces hours after initial NP introduction and agitating conditions, illustrating feasibility for plastic-bound NPs to interact with biota and surrounding matter. Our model studies reveal important interactions between low-volatility environmental toxins and microplastics and hold potential to correlate the environmental fate of endocrine disrupting toxins in the Great Lakes with molecular behaviors.

  20. Modelling annual pasture dynamics: Application to stomatal ozone deposition

    Science.gov (United States)

    González-Fernández, Ignacio; Bermejo, Victoria; Elvira, Susana; Sanz, Javier; Gimeno, Benjamín S.; Alonso, Rocío

    2010-07-01

    Modelling ozone (O 3) deposition for impact risk assessment is still poorly developed for herbaceous vegetation, particularly for Mediterranean annual pastures. High inter-annual climatic variability in the Mediterranean area makes it difficult to develop models characterizing gas exchange behaviour and air pollutant absorption suitable for risk assessment. This paper presents a new model to estimate stomatal conductance (g s) of Trifolium subterraneum, a characteristic species of dehesa pastures. The MEDPAS (MEDiterranean PAStures) model couples 3 modules estimating soil water content (SWC), vegetation growth and gs. The gs module is a reparameterized version of the stomatal component of the EMEP DO 3SE O 3 deposition model. The MEDPAS model was applied to two contrasting years representing typical dry and humid springs respectively and with different O 3 exposures. The MEDPAS model reproduced realistically the gs seasonal and inter-annual variations observed in the field. SWC was identified as the major driver of differences across years. Despite the higher O 3 exposure in the dry year, meteorological conditions favoured 2.1 times higher gs and 56 day longer growing season in the humid year compared to the dry year. This resulted in higher ozone fluxes absorbed by T. subterraneum in the humid year. High inter-family variability was found in gas exchange rates, therefore limiting the relevance of single species O 3 deposition flux modelling for dehesa pastures. Stomatal conductance dynamics at the canopy level need to be considered for more accurate O 3 flux modelling for present and future climate scenarios in the Mediterranean area.

  1. A deposit model for magmatic iron-titanium-oxide deposits related to Proterozoic massif anorthosite plutonic suites: Chapter K in Mineral Deposit Models for Resource Assessment

    Science.gov (United States)

    Woodruff, Laurel G.; Nicholson, Suzanne W.; Fey, David L.

    2013-01-01

    This descriptive model for magmatic iron-titanium-oxide (Fe-Ti-oxide) deposits hosted by Proterozoic age massif-type anorthosite and related rock types presents their geological, mineralogical, geochemical, and geoenvironmental attributes. Although these Proterozoic rocks are found worldwide, the majority of known deposits are found within exposed rocks of the Grenville Province, stretching from southwestern United States through eastern Canada; its extension into Norway is termed the Rogaland Anorthosite Province. This type of Fe-Ti-oxide deposit dominated by ilmenite rarely contains more than 300 million tons of ore, with between 10- to 45-percent titanium dioxide (TiO2), 32- to 45-percent iron oxide (FeO), and less than 0.2-percent vanadium (V).

  2. Development of a dust deposition forecast model for a mine tailings impoundment

    Science.gov (United States)

    Stovern, Michael

    Wind erosion, transport and deposition of particulate matter can have significant impacts on the environment. It is observed that about 40% of the global land area and 30% of the earth's population lives in semiarid environments which are especially susceptible to wind erosion and airborne transport of contaminants. With the increased desertification caused by land use changes, anthropogenic activities and projected climate change impacts windblown dust will likely become more significant. An important anthropogenic source of windblown dust in this region is associated with mining operations including tailings impoundments. Tailings are especially susceptible to erosion due to their fine grain composition, lack of vegetative coverage and high height compared to the surrounding topography. This study is focused on emissions, dispersion and deposition of windblown dust from the Iron King mine tailings in Dewey-Humboldt, Arizona, a Superfund site. The tailings impoundment is heavily contaminated with lead and arsenic and is located directly adjacent to the town of Dewey-Humboldt. The study includes in situ field measurements, computational fluid dynamic modeling and the development of a windblown dust deposition forecasting model that predicts deposition patterns of dust originating from the tailings impoundment. Two instrumented eddy flux towers were setup on the tailings impoundment to monitor the aeolian and meteorological conditions. The in situ observations were used in conjunction with a computational fluid dynamic (CFD) model to simulate the transport of windblown dust from the mine tailings to the surrounding region. The CFD model simulations include gaseous plume dispersion to simulate the transport of the fine aerosols, while individual particle transport was used to track the trajectories of larger particles and to monitor their deposition locations. The CFD simulations were used to estimate deposition of tailings dust and identify topographic mechanisms

  3. Distributed Modeling of soil erosion and deposition affected by buffer strips

    DEFF Research Database (Denmark)

    Khademalrasoul, Ataalah; Heckrath, Goswin Johann; Iversen, Bo Vangsø

    bodies. Buffer zones can be efficient in terms of retaining sediment and phosphorus transported by water erosion. This study aimed at parameterizing a spatial distributed erosion model to evaluate the effect of different buffer zone properties and dimension. It was our hypothesis that the placement...... and dimension of buffer zones in the landscape can be optimized by means of spatially distributed erosion and deposition modeling. During the period from 1998 to 2000 field campaigns were done on a range of agricultural land in Denmark. On 21 slope units and adjacent buffer zones, rill erosion and deposition...... was surveyed during the runoff season. In addition, organic carbon and phosphorous contents as well as bulk density were determined in soils of eroding and depositional sites. General buffer zone properties were recorded. Here we present results from scenario analyses comparing measured sediment deposition...

  4. Modeling and simulation of NiO dissolution and Ni deposition in molten carbonate fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Suk Woo; Choi, Hyung-Joon; Lim, Tae Hoon [Korea Institute of Science & Technology, Seoul (Korea, Republic of)] [and others

    1996-12-31

    Dissolution of NiO cathode into the electrolyte matrix is an important phenomena limiting the lifetime of molten carbonate fuel cell (MCFC). The dissolved nickel diffuses into the matrix and is reduced by dissolved hydrogen leading to the formation of metallic nickel films in the pores of the matrix. The growth of Ni films in the electrolyte matrix during the continuous cell operation results eventually in shorting between cathode and anode. Various mathematical and empirical models have been developed to describe the NiO dissolution and Ni deposition processes, and these models have some success in estimating the lifetime of MCFC by correlating the amount of Ni deposited in the matrix with shorting time. Since the exact mechanism of Ni deposition was not well understood, deposition reaction was assumed to be very fast in most of the models and the Ni deposition region was limited around a point in the matrix. In fact, formation of Ni films takes place in a rather broad region in the matrix, the location and thickness of the film depending on operating conditions as well as matrix properties. In this study, we assumed simple reaction kinetics for Ni deposition and developed a mathematical model to get the distribution of nickel in the matrix.

  5. Short communication: fused deposition models from CT scans.

    Science.gov (United States)

    Meakin, J R; Shepherd, D E T; Hukins, D W L

    2004-06-01

    Fused deposition modelling (FDM) is a new method for rapid prototyping, a technique that produces models of objects from computer files. The most commonly used rapid prototyping technique for medical applications is stereolithography, but FDM has several potential advantages. This paper is concerned with the accuracy of an FDM model of a sheep lumbar vertebra using data from a CT scan. The model and the original vertebra were compared by making measurements with vernier callipers and by laser scanning. Visually, the model reproduced the features of the original object; this conclusion was supported by a comparison of the laser scans. Discrepancies in measurements were comparable with those of models produced using other rapid prototyping techniques, demonstrating that FDM is a viable method for making models for clinical use.

  6. 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

  7. The Manufacture of Honeycomb Cores using Fused Deposition Modelling

    OpenAIRE

    Pollard, Dave; Ward, Carwyn; Herrmann, Guido; Etches, Julie

    2016-01-01

    Sandwich panels are used in many industries, for the advantageous properties of high stiffness, good strength to weight ratio, and impact resistance. Modern manufacturing methods are dominated by manual layup; secondary structure panels often contain multiple core components, complex geometries, and tight placement tolerances. This paper compares cores manufactured using Fused Deposition Modelling (FDM) with conventional Nomex core. FDM is a process of creating complex components from extrude...

  8. Testing of Materials for Rapid Prototyping Fused Deposition Modelling Technology

    OpenAIRE

    L. Novakova-Marcincinova; J. Novak-Marcincin

    2012-01-01

    Paper presents knowledge about types of test in area of materials properties of selected methods of rapid prototyping technologies. In today used rapid prototyping technologies for production of models and final parts are used materials in initial state as solid, liquid or powder material structure. In solid state are used various forms such as pellets, wire or laminates. Basic range materials include paper, nylon, wax, resins, metals and ceramics. In Fused Deposition Mod...

  9. A predictive model for the chemical vapor deposition of polysilicon in a cold wall, rapid thermal system

    Energy Technology Data Exchange (ETDEWEB)

    Toprac, A.J.; Trachtenberg, I.; Edgar, T.F. (Univ. of Texas, Austin, TX (United States). Dept. of Chemical Engineering)

    1994-06-01

    The chemical vapor deposition of polysilicon from thermally activated silane in a cold wall, single-wafer rapid thermal system was studied by experimentation at a variety of low pressure conditions, including very high temperatures. The effect of diluent gas on polysilicon deposition rates was examined using hydrogen, helium, and krypton. A mass-transfer model for the chemical vapor deposition of polysilicon in a cold wall, rapid thermal system was developed. This model was used to produce an empirical rate expression for silicon deposition from silane by regressing kinetic parameters to fit experimental data. The resulting model provided accurate predictions over widely varying conditions in the experimental data.

  10. A Study of Deposition Coatings Formed by Electroformed Metallic Materials.

    Directory of Open Access Journals (Sweden)

    Shoji Hayashi

    Full Text Available Major joining methods of dental casting metal include brazing and laser welding. However, brazing cannot be applied for electroformed metals since heat treatment could affect the fit, and, therefore, laser welding is used for such metals. New methods of joining metals that do not impair the characteristics of electroformed metals should be developed. When new coating is performed on the surface of the base metal, surface treatment is usually performed before re-coating. The effect of surface treatment is clinically evaluated by peeling and flex tests. However, these testing methods are not ideal for deposition coating strength measurement of electroformed metals. There have been no studies on the deposition coating strength and methods to test electroformed metals. We developed a new deposition coating strength test for electroformed metals. The influence of the negative electrolytic method, which is one of the electrochemical surface treatments, on the strength of the deposition coating of electroformed metals was investigated, and the following conclusions were drawn: 1. This process makes it possible to remove residual deposits on the electrodeposited metal surface layer. 2. Cathode electrolysis is a simple and safe method that is capable of improving the surface treatment by adjustments to the current supply method and current intensity. 3. Electrochemical treatment can improve the deposition coating strength compared to the physical or chemical treatment methods. 4. Electro-deposition coating is an innovative technique for the deposition coating of electroformed metal.

  11. Computational Fluid Dynamics Modeling of Bacillus anthracis Spore Deposition in Rabbit and Human Respiratory Airways

    Energy Technology Data Exchange (ETDEWEB)

    Kabilan, Senthil; Suffield, Sarah R.; Recknagle, Kurtis P.; Jacob, Rick E.; Einstein, Daniel R.; Kuprat, Andrew P.; Carson, James P.; Colby, Sean M.; Saunders, James H.; Hines, Stephanie; Teeguarden, Justin G.; Straub, Tim M.; Moe, M.; Taft, Sarah; Corley, Richard A.

    2016-09-30

    Three-dimensional computational fluid dynamics and Lagrangian particle deposition models were developed to compare the deposition of aerosolized Bacillus anthracis spores in the respiratory airways of a human with that of the rabbit, a species commonly used in the study of anthrax disease. The respiratory airway geometries for each species were derived from computed tomography (CT) or µCT images. Both models encompassed airways that extended from the external nose to the lung with a total of 272 outlets in the human model and 2878 outlets in the rabbit model. All simulations of spore deposition were conducted under transient, inhalation-exhalation breathing conditions using average species-specific minute volumes. The highest exposure concentration was modeled in the rabbit based upon prior acute inhalation studies. For comparison, human simulation was also conducted at the same concentration. Results demonstrated that regional spore deposition patterns were sensitive to airway geometry and ventilation profiles. Due to the complex airway geometries in the rabbit nose, higher spore deposition efficiency was predicted in the upper conducting airways compared to the human at the same air concentration of anthrax spores. As a result, higher particle deposition was predicted in the conducting airways and deep lung of the human compared to the rabbit lung due to differences in airway branching pattern. This information can be used to refine published and ongoing biokinetic models of inhalation anthrax spore exposures, which currently estimate deposited spore concentrations based solely upon exposure concentrations and inhaled doses that do not factor in species-specific anatomy and physiology.

  12. Nopal I uranium deposit: A study of radionuclide migration

    International Nuclear Information System (INIS)

    Wong, V.; Anthony, E.; Goodell, P.

    1996-01-01

    This summary reports on activities of naturally-occurring radionuclides for the Nopal I uranium deposit located in the Pena Blanca Uranium District, Chihuahua, Mexico. Activities were determined using gamma-ray spectroscopy. In addition, data reduction procedures and sample preparation (for Rn retention) will be discussed here. Nopal I uranium deposit has been identified as one of the most promising sites for analogue studies to the proposed high-level nuclear waste repository at Yucca Mountain, Nevada. The objective of this research is to study the potential for radionuclide migration by testing whether any portion of the deposit is in secular equilibrium

  13. Evaluation of the various biokinetic models of liberation from characteristic deposition fraction of brazilian population sample

    International Nuclear Information System (INIS)

    Reis, Arlene A. dos; Cardoso, Joaquim C.S.; Lourenco, Maria Cristina

    2005-01-01

    The Publication 66 of International Commission of Radiological Protection (ICRP, 1994) presented the Human Respiratory tract Model that simulates the deposition and translocation of radioactive material in the air that penetrates in the body by inhalation. The main objective of this study is to evaluate the variation in fractional activity absorbed into blood when physiological and morphological parameters from Brazilian population are applied in the deposition model. The clearance model was implemented in the software Excel (version 2000) using a system of differential equations to solve simultaneous process of translocation and absorption of material deposited. After implementation were applied in the model fractional deposition calculated by deposition model using physiological and morphological parameters from Brazilian population. The results show that the variation in the clearance model depends on the material dissolution. For materials of rapid absorption, the variations calculated are not significant. Materials of moderate and slow absorption, presented variation greater than 20% in fractional activity absorbed into blood, depending on levels of exercise. (author)

  14. Multiscale Modeling of Chemical Vapor Deposition (CVD Apparatus: Simulations and Approximations

    Directory of Open Access Journals (Sweden)

    Juergen Geiser

    2013-02-01

    Full Text Available We are motivated to compute delicate chemical vapor deposition (CVD processes. Such processes are used to deposit thin films of metallic or ceramic materials, such as SiC or a mixture of SiC and TiC. For practical simulations and for studying the characteristics in the deposition area, we have to deal with delicate multiscale models. We propose a multiscale model based on two different software packages. The large scales are simulated with computational fluid dynamics (CFD software based on the transportreaction model (or macroscopic model, and the small scales are simulated with ordinary differential equations (ODE software based on the reactive precursor gas model (or microscopic model. Our contribution is to upscale the correlation of the underlying microscale species to the macroscopic model and reformulate the fast reaction model. We obtain a computable model and apply a standard CFD software code without losing the information of the fast processes. For the multiscale model, we present numerical results of a real-life deposition process.

  15. Regional deposition of thoron progeny in models of the human tracheobronchial tree

    Energy Technology Data Exchange (ETDEWEB)

    Smith, S.M.; Cheng, Yung-Sung; Yeh, Hsu-Chi

    1995-12-01

    Models of the human tracheobronchial tree have been used to determine total and regional aerosol deposition of inhaled particles. Particle sizes measured in these studies have all been > 40 nm in diameter. The deposition of aerosols < 40 nm in diameter has not been measured. Particles in the ultrafine aerosol size range include some combustion aerosols and indoor radon progeny. Also, the influence of reduced lung size and airflow rates on particle deposition in young children has not been determined. With their smaller lung size and smaller minute volumes, children may be at increased risk from ultrafine pollutants. In order to accurately determine dose of inhaled aerosols, the effects of particle size, minute volume, and age at exposure must be quantified. The purpose of this study was to determine the deposition efficiency of ultrafine aerosols smaller than 40 nm in diameter in models of the human tracheobronchia tree. This study demonstrates that the deposition efficiency of aerosols in the model of the child`s tracheobronchial tree may be slightly higher than in the adult models.

  16. A model for human calcium pyrophosphate crystal deposition disease: crystallization kinetics in a gelatin matrix.

    Science.gov (United States)

    Mandel, N S; Mandel, G S

    1984-01-01

    A model for the deposition of calcium pyrophosphate dihydrate (CPPD) crystals in cartilage observed in human CPPD crystal deposition disease has been developed using diffusion of calcium and pyrophosphate ions through a denatured collagen matrix environment at physiologic pH. This model system uses biological grade gelatin and has allowed for the study of crystal deposition over a wide range of calcium and pyrophosphate concentrations, including physiologic levels. The model has reproducibly formed the two crystallographic dimorphs observed clinically: triclinic and monoclinic calcium pyrophosphate dihydrate. In addition, amorphous calcium pyrophosphate has been identified, and is the first species to form in the crystallization process and transforms to orthorhombic calcium pyrophosphate tetrahydrate. This in turn dissolves with a very localized increase in available pyrophosphate leading to the formation of triclinic and monoclinic calcium pyrophosphate dihydrate. The denatured collagen matrix has allowed for the formation of the two in vivo crystals at pyrophosphate concentrations lower than previously reported in solution studies.

  17. Numerical modelling of the erosion and deposition of sand inside a filter layer

    DEFF Research Database (Denmark)

    Jacobsen, Niels Gjøl; van Gent, Marcel R. A.; Fredsøe, Jørgen

    2017-01-01

    This paper treats the numerical modelling of the behaviour of a sand core covered by rocks and exposed to waves. The associated displacement of the rock is also studied. A design that allows for erosion and deposition of the sand core beneath a rock layer in a coastal structure requires an accurate...... prediction method to assure that the amount of erosion remains within acceptable limits. This work presents a numerical model that is capable of describing the erosion and deposition patterns inside of an open filter of rock on top of sand. The hydraulic loading is that of incident irregular waves...... additional data sets on the erosion and deposition patterns inside of an open filter. A few cases are defined to study the effect of the sinking of the filter into the erosion hole. The numerical model is also applied to several application cases. The response of the core material (sand) to changes...

  18. Modelling of the aerosol deposition in a hydrogen catalytic recombiner

    International Nuclear Information System (INIS)

    Vendel, J.; Studer, E.; Zavaleta, P.; Hadida, Ph.

    1997-01-01

    Catalytic recombiners are used to remove the hydrogen released in case of a severe accident in a nuclear power plant, so as to reduce the risk of deflagration or detonation. H 2 PAR experiments are carried out to precise the behaviour of recombiners in term of poisoning by aerosols. Firstly, some calculations have been done with the Trio-EF code to assess the structure of convection loops in the experimental tent. We note that when the recombiner is active, it may have a strong influence on the flow inside the tent and may even interact with an other heat source such as a furnace. In the second part, we study the deposition of aerosols on catalytic plates for a given recombiner, when it is active or passive. We list the different mechanisms and quantify them by introducing the deposition velocity. In fact, thermophoresis appears to be the main mechanism, compared to brownian diffusion or difrusiophoresis, which governs aerosols deposition. It favours deposition on > plates and acts against it for > plates. (author)

  19. Kinetic growth of random-like and ballistic-like deposition models

    International Nuclear Information System (INIS)

    Wei Wang; Cerdeira, H.A.

    1993-03-01

    The pattern structure and the scaling behaviour of the surface width for two deposition models of two kinds of particles, particle-A with a probability 1-P and particle-C with a probability P, depositing on a (1+1)-dimensional substrate are studied. For model I, a random-like deposition model, the pattern has a compact structure, and the surface width growth only depends on the time, W ∼ t 1/2 for the early stage and W ∼ t β(P) for the intermediate time where β is a function of P, as well as W ∼ P -γ for the later time. For model II, a ballistic-like deposition model, the pattern and scaling behaviour are similar to the ballistic deposition. The scaling of the surface width is W ∼ t β(P) for the early stage of growth, and W ∼ L α for later stage. The exponent β is of function of P while α is independent of P. (author). 13 refs, 5 figs, 2 tabs

  20. Phenomenological study of aerosol dry deposition in urban area: surface properties, turbulence and local meteorology influences

    International Nuclear Information System (INIS)

    Roupsard, P.

    2013-01-01

    Aerosol dry deposition is not much known for urban areas due to the lack of data. Knowledge on this phenomenon is necessary to understand pollutant fluxes in cities and to estimate inhabitant exposition to ionizing radiation of radioactive aerosols. A data providing could enable to enhance dry deposition models for these areas. An original experimental approach is performed to study submicron aerosol dry deposition on urban surfaces. Wind tunnel coupled to in situ experiments give results to study different physical phenomenon governing dry deposition. Dry deposition velocities are measured using aerosol tracers. These data are associated to turbulent and meteorological measured conditions. This database permits to classify the principal physical phenomenon for each experiment type. Finally, different phenomenon must be considered for chronic and acute exposition of urban surfaces to atmospheric particles. (author)

  1. An analytical kinetic model for chemical-vapor deposition of pureB layers from diborane

    NARCIS (Netherlands)

    Mohammadi, V.; De Boer, W.B.; Nanver, L.K.

    2012-01-01

    In this paper, an analytical model is established to describe the deposition kinetics and the deposition chamber characteristics that determine the deposition rates of pure boron (PureB-) layers grown by chemical-vapor deposition (CVD) from diborane (B2H6) as gas source on a non-rotating silicon

  2. Study of heat flux deposition in the Tore Supra Tokamak

    International Nuclear Information System (INIS)

    Carpentier, S.

    2009-02-01

    Accurate measurements of heat loads on internal tokamak components is essential for protection of the device during steady state operation. The optimisation of experimental scenarios also requires an in depth understanding of the physical mechanisms governing the heat flux deposition on the walls. The objective of this study is a detailed characterisation of the heat flux to plasma facing components (PFC) of the Tore Supra tokamak. The power deposited onto Tore Supra PFCs is calculated using an inverse method, which is applied to both the temperature maps measured by infrared thermography and to the enthalpy signals from calorimetry. The derived experimental heat flux maps calculated on the toroidal pumped limiter (TPL) are then compared with theoretical heat flux density distributions from a standard SOL-model. They are two experimental observations that are not consistent with the model: significant heat flux outside the theoretical wetted area, and heat load peaking close to the tangency point between the TPL and the last closed field surface (LCFS). An experimental analysis for several discharges with variable security factors q is made. In the area consistent with the theoretical predictions, this parametric study shows a clear dependence between the heat flux length λ q (estimated in the SOL (scrape-off layer) from the IR measurements) and the magnetic configuration. We observe that the spreading of heat fluxes on the component is compensated by a reduction of the power decay length λ q in the SOL when q decreases. On the other hand, in the area where the derived experimental heat loads are not consistent with the theoretical predictions, we observe that the spreading of heat fluxes outside the theoretical boundary increases when q decreases, and is thus not counterbalanced. (author)

  3. Fogwater deposition modeling for terrestrial ecosystems: A review of developments and measurements

    Science.gov (United States)

    Katata, Genki

    2014-07-01

    Recent progress in modeling fogwater (and low cloud water) deposition over terrestrial ecosystems during fogwater droplet interception by vegetative surfaces is reviewed. Several types of models and parameterizations for fogwater deposition are discussed with comparing assumptions, input parameter requirements, and modeled processes. The relationships among deposition velocity of fogwater (Vd) in model results, wind speed, and plant species structures associated with literature values are gathered for model validation. Quantitative comparisons between model results and observations in forest environments revealed differences as large as 2 orders of magnitude, which are likely caused by uncertainties in measurement techniques over heterogeneous landscapes. Results from the literature review show that Vd values ranged from 2.1 to 8.0 cm s-1 for short vegetation, whereas Vd = 7.7-92 cm s-1 and 0-20 cm s-1 for forests measured by throughfall-based methods and the eddy covariance method, respectively. This review also discusses the current understanding of the impacts of fogwater deposition on atmosphere-land interactions and over complex terrain based on results from numerical studies. Lastly, future research priorities in innovative modeling and observational approaches for model validation are outlined.

  4. Mechanistic Model for Ash Deposit Formation in Biomass Suspension Firing. Part 1: Model Verification by Use of Entrained Flow Reactor Experiments

    DEFF Research Database (Denmark)

    Hansen, Stine Broholm; Jensen, Peter Arendt; Jappe Frandsen, Flemming

    2017-01-01

    Two models for deposit formation in suspension firing of biomass have been developed. Both models describe deposit buildup by diffusion and subsequent condensation of vapors, thermophoresis of aerosols, convective diffusion of small particles, impaction of large particles, and reaction. The models...... stronger influence of this parameter. Model #2 was able to provide a reasonable description of the influence of temperature on the deposit buildup rates observed in the EFR experiments. A parametric study was conducted to examine the influence of some physical parameters, including ash concentration...... used to describe the deposit formation rates and deposit chemistry observed in a series of entrained flow reactor (EFR) experiments using straw and wood as fuels. It was found that model #1 was not able to describe the observed influence of temperature on the deposit buildup rates, predicting a much...

  5. A model to explain joint patterns found in ignimbrite deposits

    Science.gov (United States)

    Tibaldi, A.; Bonali, F. L.

    2018-03-01

    The study of fracture systems is of paramount importance for economic applications, such as CO2 storage in rock successions, geothermal and hydrocarbon exploration and exploitation, and also for a better knowledge of seismogenic fault formation. Understanding the origin of joints can be useful for tectonic studies and for a geotechnical characterisation of rock masses. Here, we illustrate a joint pattern discovered in ignimbrite deposits of South America, which can be confused with conjugate tectonic joint sets but which have another origin. The pattern is probably common, but recognisable only in plan view and before tectonic deformation obscures and overprints it. Key sites have been mostly studied by field surveys in Bolivia and Chile. The pattern is represented by hundreds-of-meters up to kilometre-long swarms of master joints, which show circular to semi-circular geometries and intersections that have "X" and "Y" patterns. Inside each swarm, joints are systematic, rectilinear or curvilinear in plan view, and as much as 900 m long. In section view, they are from sub-vertical to vertical and do not affect the underlying deposits. Joints with different orientation mostly interrupt each other, suggesting they have the same age. This joint architecture is here interpreted as resulting from differential contraction after emplacement of the ignimbrite deposit above a complex topography. The set of the joint pattern that has suitable orientation with respect to tectonic stresses may act to nucleate faults.

  6. Ellipsometric study of nanostructured carbon films deposited by pulsed laser deposition

    International Nuclear Information System (INIS)

    Bereznai, M.; Budai, J.; Hanyecz, I.; Kopniczky, J.; Veres, M.; Koos, M.; Toth, Z.

    2011-01-01

    When depositing carbon films by plasma processes the resulting structure and bonding nature strongly depends on the plasma energy and background gas pressure. To produce different energy plasma, glassy carbon targets were ablated by laser pulses of different excimer lasers: KrF (248 nm) and ArF (193 nm). To modify plume characteristics argon atmosphere was applied. The laser plume was directed onto Si substrates, where the films were grown. To evaluate ellipsometric measurements first a combination of the Tauc-Lorentz oscillator and the Sellmeier formula (TL/S) was applied. Effective Medium Approximation models were also used to investigate film properties. Applying argon pressures above 10 Pa the deposits became nanostructured as indicated by high resolution scanning electron microscopy. Above ∼ 100 and ∼ 20 Pa films could not be deposited by KrF and ArF laser, respectively. Our ellipsometric investigations showed, that with increasing pressure the maximal refractive index of both series decreased, while the optical band gap starts with a decrease, but shows a non monotonous course. Correlation between the size of the nanostructures, bonding structure, which was followed by Raman spectroscopy and optical properties were also investigated.

  7. Modeling the Sulfate Deposition to the Greenland Ice Sheet From the Laki Eruption

    Science.gov (United States)

    Oman, L.; Robock, A.; Stenchikov, G.; Thordarson, T.; Gao, C.

    2005-12-01

    Using the state of the art Goddard Institute for Space Studies (GISS) modelE general circulation model, simulations were conducted of the chemistry and transport of aerosols resulting from the 1783-84 Laki (64°N) flood lava eruption. A set of 3 ensemble simulations from different initial conditions were conducted by injecting our estimate of the SO2 gas into the atmosphere by the 10 episodes of the eruption and allowing the sulfur chemistry model to convert this gas into sulfate aerosol. The SO2 gas and sulfate aerosol is transported by the model and wet and dry deposition is calculated over each grid box during the simulation. We compare the resulting sulfate deposition to the Greenland Ice Sheet in the model to 23 ice core measurements and find very good agreement. The model simulation deposits a range of 169 to over 300 kg/km2 over interior Greenland with much higher values along the coastal areas. This compares to a range of 62 to 324 kg/km2 for the 23 ice core measurements with an average value of 158 kg/km2. This comparison is one important model validation tool. Modeling and observations show fairly large spatial variations in the deposition of sulfate across the Greenland Ice Sheet for the Laki eruption, but the patterns are similar to those we modeled for the 1912 Katmai and 1991 Pinatubo eruptions. Estimates of sulfate loading based on single ice cores can show significant differences, so ideally several ice cores should be combined in reconstructing the sulfate loading of past volcanic eruptions, taking into account the characteristic spatial variations in the deposition pattern.

  8. Studies on geneses of Lianshanguan granites and Lianshanguan uranium ore deposit

    International Nuclear Information System (INIS)

    Zhang Jiafu; Xu Guoqing; Wang Wenguang

    1994-02-01

    Based on the field work, and through the studies of thin-sections, minerals fluid inclusions, isotope geology, rare-earth elements and U-content in rocks and minerals, it is suggested that Lianshanguan granites are of magmatization genesis with multistage. The genetic model of mineralization of Lianshanguan uranium ore deposit is the magmatization-hydrothermal-filled uranium type. The role of mineralization of uranium ore deposit in that area is discussed. Furthermore, the direction of prospecting and following prospecting criteria for similar deposits in this area are also given

  9. Electrophoretic deposition: a quantitative model for particle deposition and binder formation from alcohol-based suspensions

    NARCIS (Netherlands)

    Beer, De E.; Duval, J.F.L.; Meulenkamp, E.A.

    2000-01-01

    We investigated electrophoretic deposition from a suspension containing positively charged particles, isopropanol, water, and Mg(NO3)2, with the aim of describing the deposition rates of the particles and Mg(OH)2, which is formed due to chemical reactions at the electrode, in terms of quantitative

  10. Response of Sphagnum fuscum to Nitrogen Deposition: A Case Study of Ombrogenous Peatlands in Alberta, Canada

    Science.gov (United States)

    Vitt, D.H.; Wieder, K.; Halsey, L.A.; Turetsky, M.

    2003-01-01

    Peatlands cover about 30% of northeastern Alberta and are ecosystems that are sensitive to nitrogen deposition. In polluted areas of the UK, high atmospheric N deposition (as a component of acid deposition) has been considered among the causes of Sphagnum decline in bogs (ombrogenous peatlands). In relatively unpolluted areas of western Canada and northern Sweden, short-term experimental studies have shown that Sphagnum responds quickly to nutrient loading, with uptake and retention of nitrogen and increased production. Here we examine the response of Sphagnum fuscum to enhanced nitrogen deposition generated during 34 years of oil sands mining through the determination of net primary production (NPP) and nitrogen concentrations in the upper peat column. We chose six continental bogs receiving differing atmospheric nitrogen loads (modeled using a CALPUFF 2D dispersion model). Sphagnum fuscum net primary production (NPP) at the high deposition site (Steepbank - mean of 600 g/m2; median of 486 g/m2) was over three times as high than at five other sites with lower N deposition. Additionally, production of S. fuscum may be influenced to some extent by distance of the moss surface from the water table. Across all sites, peat nitrogen concentrations are highest at the surface, decreasing in the top 3 cm with no significant change with increasing depth. We conclude that elevated N deposition at the Steepbank site has enhanced Sphagnum production. Increased N concentrations are evident only in the top 1-cm of the peat profile. Thus, 34 years after mine startup, increased N-deposition has increased net primary production of Sphagnum fuscum without causing elevated levels of nitrogen in the organic matter profile. A response to N-stress for Sphagnum fuscum is proposed at 14-34 kg ha-1 yr-1. A review of N-deposition values reveals a critical N-deposition value of between 14.8 and 15.7 kg ha -1 yr-1 for NPP of Sphagnum species.

  11. CFD Modeling of Sodium-Oxide Deposition in Sodium-Cooled Fast Reactor Compact Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Tatli, Emre; Ferroni, Paolo; Mazzoccoli, Jason

    2015-09-02

    The possible use of compact heat exchangers (HXs) in sodium-cooled fast reactors (SFR) employing a Brayton cycle is promising due to their high power density and resulting small volume in comparison with conventional shell-and-tube HXs. However, the small diameter of their channels makes them more susceptible to plugging due to Na2O deposition during accident conditions. Although cold traps are designed to reduce oxygen impurity levels in the sodium coolant, their failure, in conjunction with accidental air ingress into the sodium boundary, could result in coolant oxygen levels that are above the saturation limit in the cooler parts of the HX channels. This can result in Na2O crystallization and the formation of solid deposits on cooled channel surfaces, limiting or even blocking coolant flow. The development of analysis tools capable of modeling the formation of these deposits in the presence of sodium flow will allow designers of SFRs to properly size the HX channels so that, in the scenario mentioned above, the reactor operator has sufficient time to detect and react to the affected HX. Until now, analytical methodologies to predict the formation of these deposits have been developed, but never implemented in a high-fidelity computational tool suited to modern reactor design techniques. This paper summarizes the challenges and the current status in the development of a Computational Fluid Dynamics (CFD) methodology to predict deposit formation, with particular emphasis on sensitivity studies on some parameters affecting deposition.

  12. 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

  13. Nanoimprint Lithography on curved surfaces prepared by fused deposition modelling

    International Nuclear Information System (INIS)

    Köpplmayr, Thomas; Häusler, Lukas; Bergmair, Iris; Mühlberger, Michael

    2015-01-01

    Fused deposition modelling (FDM) is an additive manufacturing technology commonly used for modelling, prototyping and production applications. The achievable surface roughness is one of its most limiting aspects. It is however of great interest to create well-defined (nanosized) patterns on the surface for functional applications such as optical effects, electronics or bio-medical devices. We used UV-curable polymers of different viscosities and flexible stamps made of poly(dimethylsiloxane) (PDMS) to perform Nanoimprint Lithography (NIL) on FDM-printed curved parts. Substrates with different roughness and curvature were prepared using a commercially available 3D printer. The nanoimprint results were characterized by optical light microscopy, profilometry and atomic force microscopy (AFM). Our experiments show promising results in creating well-defined microstructures on the 3D-printed parts. (paper)

  14. Development of a Computational Chemical Vapor Deposition Model: Applications to Indium Nitride and Dicyanovinylaniline

    Science.gov (United States)

    Cardelino, Carlos

    1999-01-01

    A computational chemical vapor deposition (CVD) model is presented, that couples chemical reaction mechanisms with fluid dynamic simulations for vapor deposition experiments. The chemical properties of the systems under investigation are evaluated using quantum, molecular and statistical mechanics models. The fluid dynamic computations are performed using the CFD-ACE program, which can simulate multispecies transport, heat and mass transfer, gas phase chemistry, chemistry of adsorbed species, pulsed reactant flow and variable gravity conditions. Two experimental setups are being studied, in order to fabricate films of: (a) indium nitride (InN) from the gas or surface phase reaction of trimethylindium and ammonia; and (b) 4-(1,1)dicyanovinyl-dimethylaminoaniline (DCVA) by vapor deposition. Modeling of these setups requires knowledge of three groups of properties: thermodynamic properties (heat capacity), transport properties (diffusion, viscosity, and thermal conductivity), and kinetic properties (rate constants for all possible elementary chemical reactions). These properties are evaluated using computational methods whenever experimental data is not available for the species or for the elementary reactions. The chemical vapor deposition model is applied to InN and DCVA. Several possible InN mechanisms are proposed and analyzed. The CVD model simulations of InN show that the deposition rate of InN is more efficient when pulsing chemistry is used under conditions of high pressure and microgravity. An analysis of the chemical properties of DCVA show that DCVA dimers may form under certain conditions of physical vapor transport. CVD simulations of the DCVA system suggest that deposition of the DCVA dimer may play a small role in the film and crystal growth processes.

  15. Modelling of deposited black carbon with the Lagrangian particle dispersion model FLEXPART in backward mode

    Science.gov (United States)

    Eckhardt, Sabine; Cassiani, Massimo; Sollum, Espen; Evangeliou, Nikolaos; Stohl, Andreas

    2017-04-01

    Lagrangian particle dispersion models are popular tools to simulate the dispersion of trace gases, aerosols or radionuclides in the atmosphere. If they consider only linear processes, they are self-adjoint, i.e., they can be run forward and backward in time without changes to the source code. Backward simulations are very efficient if the number of receptors is smaller than the number of sources, and they are well suited to establish source-receptor (s-r) relationships for measurements of various trace substances in air. However, not only the air concentrations are of interest, but also the s-r relationships for deposition are important for interpreting measurement data. E.g., deposition of dust is measured regularly in ice cores, partly also as a proxy to understand changes in aridity in dust source regions. Contamination of snow by black carbon (BC) aerosols has recently become a hot topic because of the potential impact of BC on the snow albedo. To interpret such deposition measurements and study the sources of the deposited substance, it would be convenient to have a model that is capable of efficient s-r relationship calculations for such types of measurements. We present here the implementation of such an algorithm into the Lagrangian particle dispersion model FLEXPART, and test the new scheme by comparisons with results from forward simulations as well as comparisons with measurements. As an application, we analyse source regions for elemental carbon (EC) measured in snow over the years 2014-2016 in the Russian Arctic. Simulations using an annual constant black carbon inventory based on ECLIPSE V5 and GFED (Global Fire Emission Database), have been performed. The meteorological data used in the simulation are 3 hourly operational data from the European Centre of Medium Range Weather Forecast (ECMWF) on a 1 degree grid resolution and 138 vertical levels. The model is able to capture very well the measured concentrations. Gas flaring and residential

  16. Experimental Validation of Plastic Mandible Models Produced by a ?Low-Cost? 3-Dimensional Fused Deposition Modeling Printer

    OpenAIRE

    Maschio, Federico; Pandya, Mirali; Olszewski, Raphael

    2016-01-01

    Background The objective of this study was to investigate the accuracy of 3-dimensional (3D) plastic (ABS) models generated using a low-cost 3D fused deposition modelling printer. Material/Methods Two human dry mandibles were scanned with a cone beam computed tomography (CBCT) Accuitomo device. Preprocessing consisted of 3D reconstruction with Maxilim software and STL file repair with Netfabb software. Then, the data were used to print 2 plastic replicas with a low-cost 3D fused deposition mo...

  17. Study on the electrical properties of ITO films deposited by facing target sputter deposition

    International Nuclear Information System (INIS)

    Kim, Youn J; Jin, Su B; Kim, Sung I; Choi, Yoon S; Choi, In S; Han, Jeon G

    2009-01-01

    This study examined the mechanism for the change in the electrical properties (carrier concentration (n) and mobility (μ)) of tin-doped indium oxide (ITO) films deposited by magnetron sputtering in a confined facing magnetic field. The relationship between the carrier concentration and the mobility was significantly different from the results reported for ITO films deposited by other magnetron sputtering processes. The lowest resistivity obtained for ITO films deposited in a confined facing magnetic field at low substrate temperatures (approximately 120 0 C) was 4.26 x 10 -4 Ω cm at a power density of 3 W cm -2 . Crystalline ITO films were obtained at a low power density range from 3 to 5 W cm -2 due to the increase in the substrate temperature from 120 to 162 0 C. This contributed to the increased carrier concentration and decreased electrical resistivity. X-ray photoelectron spectroscopy revealed an increase in the concentration of the Sn 4+ states. This was attributed to the formation of a crystalline ITO film, which effectively enhanced the carrier concentration and reduced the carrier mobility.

  18. Comparison of Aerodynamic Resistance Parameterizations and Implications for Dry Deposition Modeling

    Science.gov (United States)

    Nitrogen deposition data used to support the secondary National Ambient Air Quality Standards and critical loads research derives from both measurements and modeling. Data sets with spatial coverage sufficient for regional scale deposition assessments are currently generated fro...

  19. Modelling gaseous dry deposition in AURAMS: a unified regional air-quality modelling system

    International Nuclear Information System (INIS)

    Zhang, L.; Moran, M.D.; Makar, P.A.; Brook, J.R.; Gong, S.

    2002-01-01

    An upgraded parameterization scheme for gaseous dry-deposition velocities has been developed for a new regional air-quality model with a 91-species gas-phase chemistry mechanism, of which 48 species are ''transported'' species. The well-known resistance analogy to dry deposition is adopted in the present scheme, with both O 3 and SO 2 taken as base species. Stomatal resistances are calculated for all dry-depositing species using a ''sunlit/shaded big-leaf'' canopy stomatal resistance submodel. Dry-ground, wet-ground, dry-cuticle, and wet-cuticle resistances for O 3 and SO 2 , and parameters for calculating canopy stomatal resistance and aerodynamic resistance for these two base species are given as input parameters for each of the 15 land-use categories and/or five seasonal categories considered by the scheme. Dry-ground, wet-ground, dry-cuticle, and wet-cuticle resistances for the other 29 model species for which dry deposition is considered to be a significant process are scaled to the resistances of O 3 and SO 2 based on published measurements of their dry deposition and/or their aqueous solubility and oxidizing capacity. Mesophyll resistances are treated as dependent only on chemical species. Field experimental data have then been used to evaluate the scheme's performance for O 3 and SO 2 . Example sets of modelled dry-deposition velocities have also been calculated for all 31 dry-deposited species and 15 land-use categories for different environmental conditions. This new scheme incorporates updated information on dry-deposition measurements and is able to predict deposition velocities for 31 gaseous species for different land-use types, seasons, and meteorological conditions. (author)

  20. Localization of gastrointestinal deposition of mercuric chloride studied in vivo

    International Nuclear Information System (INIS)

    Nielsen, J.B.; Andersen, H.L.; Soerensen, J.A.; Andersen, O.

    1992-01-01

    During the last 5 years, the site of gastrointestinal absorption of inorganic mercury has been attempted identified mainly by experiments using perfused intestinal segments in vitro or in situ. The present investigation will discuss the localization of the absorption site for mercuric chloride based on a completely undisturbed in vivo experimental model in mice. As the mice were allowed to eat their normal diet during the experimental period, the present results would independently add to existing knowledge on intestinal absorption sites for inorganic mercury. The mice were given 203 Hg labelled mercuric chloride orally, either through stomach tube or in the drinking water, and were killed after various time intervals. Mercury was localized and quantified in various segments of the gastrointestinal tract by gamma-counting. Time course analysis of the segmental deposition of mercury demonstrated that the deposition mainly takes place in the proximal jejunum and suggested that a larger part of the jejunum than previously reported is involved in absorption of mercury. Using this in vivo model, tetraethylthiuram disulfide was demonstrated to increase the intestinal deposition and absorption without changing the site of deposition. (au)

  1. Study of the acidic deposition phenomenon over Alexandria city.

    Science.gov (United States)

    Noweir, Kamal H; El-Marakby, Fadia A; Zaki, Gihan R; Ibrahim, Alaa K

    2008-01-01

    Acid deposition commonly occurs due to conversion of primary acidic pollutants (SO2 & NO2) into secondary pollutants (H2SO4 & HNO3 and their salts). The main natural sources of acid deposition in Alexandria include lightening and microbial processes. Anthropogenic sources include traffic, industrial, fuel burning, and incineration activities. Acid deposition has ecological and economic effects in addition to health effects. The objective of this study is to assess acidity of dry and wet depositions in the atmosphere of Alexandria. Dry samples were collected as settled dust using plastic jar. Wet samples were collected as rain water using polyethylene bottle. All samples were analyzed for pH, sulfates, and nitrates. The relatively high pH values observed in depositions of Alexandria city (6.95+/-0.22) and (7.14+/-0.49) for settled dust and rain water respectively indicating the conversion of the formed acids (H2SO4 & HNO3) into their salts. This explanation was confirmed by the relatively high concentrations of sulfates and nitrates. The average values were (14.3+/-4.21 g/km2/month and 20.5+/-9.5mg/L for sulfates), and (22.6+/-10.6 g/km2/month and 0.5+/-0.32 mg/L for nitrates) for settled dust and rainwater samples respectively. It can be concluded that Alexandria is a lucky city regarding acidity of the atmosphere due to its geographic, topographic, and meteorological features. Building up acid deposition monitoring network that covers all Egyptian cities to be a nucleus for African network, using new technologies that reduce emission of acid deposition precursors and alternative sources of energy, implementing and enforcing regulations and standards for major pollutants, and increasing public awareness are recommended.

  2. Laboratory Deposition Apparatus to Study the Effects of Wax Deposition on Pipe Magnetic Field Leakage Signals

    Directory of Open Access Journals (Sweden)

    Karim Mohd Fauzi Abd

    2014-07-01

    Full Text Available Accurate technique for wax deposition detection and severity measurement on cold pipe wall is important for pipeline cleaning program. Usually these techniques are validated by conventional techniques on laboratory scale wax deposition flow loop. However conventional techniques inherent limitations and it is difficult to reproduce a predetermine wax deposit profile and hardness at designated location in flow loop. An alternative wax deposition system which integrates modified pour casting method and cold finger method is presented. This system is suitable to reproduce high volume of medium hard wax deposit in pipe with better control of wax deposit profile and hardness.

  3. Interlaboratory model comparisons of atmospheric concentrations with and without deposition

    International Nuclear Information System (INIS)

    Kern, C.D.; Cooper, R.E.

    1978-01-01

    To calculate the dose to the regional and U.S. populations, the pollutant concentration both with and without deposition and the amount of material deposited on the ground and watersheds around such a facility must be known. The following report (Article 50) of this document contains some initial estimates of population exposure from atmospheric effluents. The expertise of laboratories supported by U.S. Department of Energy funds ensures that the latest methods and data are available. Lawrence Livermore Laboratory (LLL) performed regional calculations (out to distances of the order of 200 km from a hypothetical fuel reprocessing plant). The Air Resources Laboratory (ARL) of the National Oceanic and Atmospheric Administration (NOAA), and Battelle Pacific Northwest Laboratories (PNL) performed U.S. scale calculations, and ARL also did the global calculations. Data from a winter and summer period were used to make comparisons of calculations by LLL, ARL, and PNL to determine which model should be used for the final calculations and to determine if a 200-km square area centered on the site would be large enough for dose calculations via the water and food pathways

  4. A dermal model for spray painters. Part I: subjective exposure modelling of spray paint deposition.

    Science.gov (United States)

    Brouwer, D H; Semple, S; Marquart, J; Cherrie, J W

    2001-01-01

    The discriminative power of existing dermal exposure models is limited. Most models only allow occupational hygienists to rank workers between and within workplaces according to broad bands of dermal exposure. No allowance is made for the work practices of different individuals. In this study a process-based, structured approach has been used to estimate dermal exposure from overspray generated by a spray painting process. Factors for spray technique, object shape and workers' individual work practices involved in the processes of droplet formation and deposition were incorporated into the model. The model was applied to predict dermal exposure of airless spray painters and the results were compared with exposure data. The predicted levels of exposure showed reasonable rank correlation with the measured exposure, although the model tended to over-predict the actual level of exposure. It was concluded that a structured, process-based approach has the potential to produce reliable estimates of dermal exposure. The reliability of exposure models of this type should be explored further and the relationship between the determinants of exposure should be validated by additional field studies.

  5. A study on particle deposition of an evaporating colloidal droplet

    Energy Technology Data Exchange (ETDEWEB)

    Wee, Sang Kwon; Lee, Jung Yong [Samsung Advanced Institute of Technology, Yongin (Korea, Republic of)

    2006-07-15

    The presented study aims to investigate the colloidal droplet deposition caused by evaporation of the liquid. In the numerical analysis, the evaporation is carried out by using different evaporation function intended to obtain different shape of solute deposition. In the experiment, the colloidal droplets of different solvents are placed on a glass plate and the surface profiles are measured after drying the solvents of the droplets to investigate the effect of the solvent evaporation on the final deposition profile. Comparing the surface profiles obtained under different conditions, the optimum drying conditions of colloidal droplets are determined to obtain uniform surface profiles. The numerical results showed that ring-shaped deposition of solute was formed at the edge of the droplet due to the coffee stain effect and the height of the ring was reduced at the lower evaporation rate. The experiments showed that the boiling point of a solvent was critical to the surface uniformity of the deposition profile and the mixture of solvents with different boiling points influenced the uniformity as well.

  6. Proton microprobe study of tin-polymetallic deposits

    Energy Technology Data Exchange (ETDEWEB)

    Murao, S. [Geological Survey of Japan, Tsukuba, Ibaraki (Japan); Sie, S.H.; Suter, G.F. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience

    1996-12-31

    Tin-polymetallic vein type deposits are a complex mixture of cassiterite and sulfides and they are the main source of technologically important rare metals such as indium and bismuth. Constituent minerals are usually fine grained having wide range of chemical composition and often the elements of interest occur as trace elements not amenable to electron microprobe analysis. PIXE with a proton microprobe can be an effective tool to study such deposits by delineating the distribution of trace elements among carrier minerals. Two representative indium-bearing deposits of tin- polymetallic type, Tosham of India (Cu-ln-Bi-Sn-W-Ag), and Mount Pleasant of Canada (Zn-Cu-In-Bi-Sn-W), were studied to delineate the distribution of medical/high-tech rare metals and to examine the effectiveness of the proton probe analysis of such ore. One of the results of the study indicated that indium and bismuth are present in chalcopyrite in the deposits. In addition to these important rare metals, zinc, copper, arsenic, antimony, selenium, and tin are common in chalcopyrite and pyrite. Arsenopyrite contains nickel, copper, zinc, silver, tin, antimony and bismuth. In chalcopyrite and pyrite, zinc, arsenic, indium, bismuth and lead are richer in Mount Pleasant ore, but silver is higher at Tosham. Also thallium and gold were found only in Tosham pyrite. The Tosham deposit is related to S-type granite, while Mount Pleasant to A-type. It appears that petrographic character of the source magma is one of the factors to determine the trace element distribution in tin-polymetallic deposit. 6 refs., 2 figs.

  7. Proton microprobe study of tin-polymetallic deposits

    International Nuclear Information System (INIS)

    Murao, S.; Sie, S.H.; Suter, G.F.

    1996-01-01

    Tin-polymetallic vein type deposits are a complex mixture of cassiterite and sulfides and they are the main source of technologically important rare metals such as indium and bismuth. Constituent minerals are usually fine grained having wide range of chemical composition and often the elements of interest occur as trace elements not amenable to electron microprobe analysis. PIXE with a proton microprobe can be an effective tool to study such deposits by delineating the distribution of trace elements among carrier minerals. Two representative indium-bearing deposits of tin- polymetallic type, Tosham of India (Cu-ln-Bi-Sn-W-Ag), and Mount Pleasant of Canada (Zn-Cu-In-Bi-Sn-W), were studied to delineate the distribution of medical/high-tech rare metals and to examine the effectiveness of the proton probe analysis of such ore. One of the results of the study indicated that indium and bismuth are present in chalcopyrite in the deposits. In addition to these important rare metals, zinc, copper, arsenic, antimony, selenium, and tin are common in chalcopyrite and pyrite. Arsenopyrite contains nickel, copper, zinc, silver, tin, antimony and bismuth. In chalcopyrite and pyrite, zinc, arsenic, indium, bismuth and lead are richer in Mount Pleasant ore, but silver is higher at Tosham. Also thallium and gold were found only in Tosham pyrite. The Tosham deposit is related to S-type granite, while Mount Pleasant to A-type. It appears that petrographic character of the source magma is one of the factors to determine the trace element distribution in tin-polymetallic deposit. 6 refs., 2 figs

  8. New developments in fused deposition modeling of ceramics

    DEFF Research Database (Denmark)

    Bellini, Anna; Shor, L.; Guceri, S.I.

    2005-01-01

    of a novel extrusion system, based on the FDM technology. The new set-up, consisting of a mini-extruder mounted on a high-precision positioning system, is fed with bulk material in granulated form, instead that with the more common filament. Findings - Previous research showed that the applications of new...... materials with specific characteristics in a commercial FDM system are limited by the use of intermediate precursors, i.e. a filament. The new design described in this paper overcomes the problem thanks to the new feeding system. Research limitations/implications - The work presented in this paper is only......Purpose - To shift from rapid prototyping (RP) to agile fabrication by broadening the material selection, e.g. using ceramics, hence improving the properties (e.g. mechanical properties) of fused deposition modeling (FDM) products. Design/methodology/approach - This paper presents the development...

  9. Design and Analysis of a Fused Deposition Modelling Manufactured Part

    Science.gov (United States)

    Diaconescu, Claudiu; Tabacu, Stefan; Oltean, Alexandru

    2017-10-01

    Fused deposition modelling (FDM) technology was investigated in order to produce a part designed to support a test load without permanent deformation. A topology optimization script was developed in order to define the final shape of the part. The solver used for the numerical analysis is LS-Dyna (implicit formulation). The algorithm follows the element removal based on the stress state and it can be very simply implemented. This solution of developing a custom code was adopted because plastic strain state was monitored and this is not yet implemented in other topology optimization applications. The results of the traction test were assembled and investigated in order to outline some of the typical parameters used for mechanical characterization. As a general overview of the results it was found that the parts manufactured using a 45°/45° stacking configuration are stronger that the ones manufactured using 0°/90° stacking configuration.

  10. New developments in fused deposition modeling of ceramics

    DEFF Research Database (Denmark)

    Bellini, Anna; Shor, L.; Guceri, S.I.

    2005-01-01

    Purpose - To shift from rapid prototyping (RP) to agile fabrication by broadening the material selection, e.g. using ceramics, hence improving the properties (e.g. mechanical properties) of fused deposition modeling (FDM) products. Design/methodology/approach - This paper presents the development...... of a novel extrusion system, based on the FDM technology. The new set-up, consisting of a mini-extruder mounted on a high-precision positioning system, is fed with bulk material in granulated form, instead that with the more common filament. Findings - Previous research showed that the applications of new...... materials with specific characteristics in a commercial FDM system are limited by the use of intermediate precursors, i.e. a filament. The new design described in this paper overcomes the problem thanks to the new feeding system. Research limitations/implications - The work presented in this paper is only...

  11. Evaluation of DUSTRAN Software System for Modeling Chloride Deposition on Steel Canisters

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Tracy T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jensen, Philip J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fritz, Brad G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Rutz, Frederick C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Devanathan, Ram [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-07-29

    The degradation of steel by stress corrosion cracking (SCC) when exposed to atmospheric conditions for decades is a significant challenge in the fossil fuel and nuclear industries. SCC can occur when corrosive contaminants such as chlorides are deposited on a susceptible material in a tensile stress state. The Nuclear Regulatory Commission has identified chloride-induced SCC as a potential cause for concern in stainless steel used nuclear fuel (UNF) canisters in dry storage. The modeling of contaminant deposition is the first step in predictive multiscale modeling of SCC that is essential to develop mitigation strategies, prioritize inspection, and ensure the integrity and performance of canisters, pipelines, and structural materials. A multiscale simulation approach can be developed to determine the likelihood that a canister would undergo SCC in a certain period of time. This study investigates the potential of DUSTRAN, a dust dispersion modeling system developed by Pacific Northwest National Laboratory, to model the deposition of chloride contaminants from sea salt aerosols on a steel canister. Results from DUSTRAN simulations run with historical meteorological data were compared against measured chloride data at a coastal site in Maine. DUSTRAN’s CALPUFF model tended to simulate concentrations higher than those measured; however, the closest estimations were within the same order of magnitude as the measured values. The decrease in discrepancies between measured and simulated values as the level of abstraction in wind speed decreased suggest that the model is very sensitive to wind speed. However, the influence of other parameters such as the distinction between open-ocean and surf-zone sources needs to be explored further. Deposition values predicted by the DUSTRAN system were not in agreement with concentration values and suggest that the deposition calculations may not fully represent physical processes. Overall, results indicate that with parameter

  12. A simple model to estimate deposition based on a statistical reassessment of global fallout data.

    Science.gov (United States)

    Pálsson, S E; Howard, B J; Bergan, T D; Paatero, J; Isaksson, M; Nielsen, S P

    2013-07-01

    Atmospheric testing of nuclear weapons began in 1945 and largely ceased in 1963. Monitoring of the resulting global fallout was carried out globally by the Environmental Measurements Laboratory and the UK Atomic Energy Research Establishment as well as at national level by some countries. A correlation was identified between fallout deposition and precipitation and an uneven distribution with latitude. In this study, the available data from 1954 to 1976 for (90)Sr and (137)Cs were reanalysed using analysis of covariance (ANCOVA) and logarithmically transformed values of the monthly deposition density as the response variable. Generalized additive models (GAM) were used to explore the relationship of different variables to the response variable and quantify the explanatory power that could be achieved. The explanatory variables which consistently explained most of the variability were precipitation at each site, latitude and change with time and a simple linear model was produced with similar explanatory power as the GAM. The estimates improved as the temporal resolution of the precipitation data increased. A good log-log fit could be obtained if a bias of about 1-6 mm precipitation per month was added, this could be interpreted as dry deposition which is not otherwise accounted for in the model. The deposition rate could then be explained as a simple non-linear power function of the precipitation rate (r(0.2-0.6) depending on latitude band). A similar non-linear power function relationship has been the outcome of some studies linking wash-out and rain-out coefficients with rain intensity. Our results showed that the precipitation rate was an important parameter, not just the total amount. The simple model presented here allows the recreation of the deposition history at a site, allowing comparison with time series of activity concentrations for different environmental compartments, which is important for model validation. Copyright © 2012 Elsevier Ltd. All rights

  13. Structural, electrical and optical studies on spray-deposited ...

    Indian Academy of Sciences (India)

    76, No. 1. — journal of. January 2011 physics pp. 153–163. Structural, electrical and optical studies on spray-deposited aluminium-doped ZnO thin films. S TEWARI1 and A BHATTACHARJEE2,∗ ... It is a versatile material with good electrical and optical ... applications for detecting hazardous gases, including LPG [13,14]. 2.

  14. Deposition and removal of fugitive dust in the arid southwestern United States: measurements and model results.

    Science.gov (United States)

    Etyemezian, Vic; Ahonen, Sean; Nikolic, Djordje; Gillies, John; Kuhns, Hampden; Gillette, Dale; Veranth, John

    2004-09-01

    This work was motivated by the need to better reconcile emission factors for fugitive dust with the amount of geologic material found on ambient filter samples. The deposition of particulate matter with aerodynamic diameter less than or equal to 10 microm (PM10), generated by travel over an unpaved road, over the first 100 m of transport downwind of the road was examined at Ft. Bliss, near El Paso, TX. The field conditions, typical for warm days in the arid southwestern United States, represented sparsely vegetated terrain under neutral to unstable atmospheric conditions. Emission fluxes of PM10 dust were obtained from towers downwind of the unpaved road at 7, 50, and 100 m. The horizontal flux measurements at the 7 m and 100 m towers indicated that PM10 deposition to the vegetation and ground was too small to measure. The data indicated, with 95% confidence, that the loss of PM10 between the source of emission at the unpaved road, represented by the 7 m tower, and a point 100 m downwind was less than 9.5%. A Gaussian model was used to simulate the plume. Values of the vertical standard deviation sigma(z) and the deposition velocity Vd were similar to the U.S. Environmental Protection Agency (EPA) ISC3 model. For the field conditions, the model predicted that removal of PM10 unpaved road dust by deposition over the distance between the point of emission and 100 m downwind would be less than 5%. However, the model results also indicated that particles larger than 10 microm (aerodynamic diameter) would deposit more appreciably. The model was consistent with changes observed in size distributions between 7 m and 100 m downwind, which were measured with optical particle counters. The Gaussian model predictions were also compared with another study conducted over rough terrain and stable atmospheric conditions. Under such conditions, measured PM10 removal rates over 95 m of downwind transport were reported to be between 86% and 89%, whereas the Gaussian model predicted

  15. Volcanogenic Massive Sulfide Deposits of the World - Database and Grade and Tonnage Models

    Science.gov (United States)

    Mosier, Dan L.; Berger, Vladimir I.; Singer, Donald A.

    2009-01-01

    Grade and tonnage models are useful in quantitative mineral-resource assessments. The models and database presented in this report are an update of earlier publications about volcanogenic massive sulfide (VMS) deposits. These VMS deposits include what were formerly classified as kuroko, Cyprus, and Besshi deposits. The update was necessary because of new information about some deposits, changes in information in some deposits, such as grades, tonnages, or ages, revised locations of some deposits, and reclassification of subtypes. In this report we have added new VMS deposits and removed a few incorrectly classified deposits. This global compilation of VMS deposits contains 1,090 deposits; however, it was not our intent to include every known deposit in the world. The data was recently used for mineral-deposit density models (Mosier and others, 2007; Singer, 2008). In this paper, 867 deposits were used to construct revised grade and tonnage models. Our new models are based on a reclassification of deposits based on host lithologies: Felsic, Bimodal-Mafic, and Mafic volcanogenic massive sulfide deposits. Mineral-deposit models are important in exploration planning and quantitative resource assessments for two reasons: (1) grades and tonnages among deposit types vary significantly, and (2) deposits of different types occur in distinct geologic settings that can be identified from geologic maps. Mineral-deposit models combine the diverse geoscience information on geology, mineral occurrences, geophysics, and geochemistry used in resource assessments and mineral exploration. Globally based deposit models allow recognition of important features and demonstrate how common different features are. Well-designed deposit models allow geologists to deduce possible mineral-deposit types in a given geologic environment and economists to determine the possible economic viability of these resources. Thus, mineral-deposit models play a central role in presenting geoscience

  16. Research study concerning the 3D printing adittion (FDM-fused deposition modeling) to design UAV (UAV-unconventional aerial vehicle) structures

    Science.gov (United States)

    Pascu, Nicoleta Elisabeta; CǎruÅ£aşu, Nicoleta LuminiÅ£a.; Geambaşu, Gabriel George; Adîr, Victor Gabriel; Arion, Aurel Florin; Ivaşcu, Laura

    2018-02-01

    Aerial vehicles have become indispensable. There are in this field UAV (Unconventional Aerial vehicle) and transportation airplanes and other aerospace vehicles for spatial tourism. Today, the research and development activity in aerospace industry is focused to obtain a good and efficient design for airplanes, to solve the problem of high pollution and to reduce the noise. For these goals are necessary to realize light and resistant components. The aerospace industry products are, generally, very complex concerning geometric shapes and the costs are high, usually. Due to the progress in this field (products obtained using FDM) was possible to reduce the number of used tools, welding belts, and, of course, to eliminate a lot of machine tools. In addition, the complex shapes are easier product using this high technology, the cost is more attractive and the time is lower. This paper allows to present a few aspects about FDM technology and the obtained structures using it, as follows: computer geometric modeling (different designing softs) to design and redesign complex structures using 3D printing, for this kind of vehicles; finite element analysis to identify what is the influence of design for different structures; testing the structures.

  17. Cenozoic unconformities and depositional supersequences of North Atlantic continental margins: testing the Vail model

    Science.gov (United States)

    Poag, C. Wylie; Ward, Lauck W.

    1987-01-01

    Integrated outcrop, borehole, and seismic reflection stratigraphy from the U.S. and Irish margins of the North Atlantic basin reveals a framework of Cenozoic depositional supersequences and interregional unconformities that resembles the Vail depositional model. Paleo-bathymetric and paleoceanographic analyses of associated microfossil assemblages indicate a genetic link between the depositional framework and the relative position of sea level.

  18. Vegetation succession as affected by decreasing nitrogen deposition, soil characteristics and site management: A modelling approach

    NARCIS (Netherlands)

    Wamelink, G.W.W.; Dobben, van H.F.; Berendse, F.

    2009-01-01

    After many years of increasing nitrogen deposition, the deposition rates are now decreasing. A major question is whether this will result in the expected positive effects on plant species diversity. Long-term experiments that investigate the effects of decreasing deposition are not available. Model

  19. New approaches in geological studies of tsunami deposits

    Science.gov (United States)

    Szczucinski, Witold

    2017-04-01

    During the last dozen of years tsunamis have appeared to be the most disastrous natural process worldwide. The dramatic, large tsunamis on Boxing Day, 2004 in the Indian Ocean and on March 11, 2011 offshore Japan caused catastrophes listed as the worst in terms of the number of victims and the economic losses, respectively. In the aftermath, they have become a topic of high public and scientific interest. The record of past tsunamis, mainly in form of tsunami deposits, is often the only way to identify tsunami risk at a particular coast due to relatively low frequency of their occurrence. The identification of paleotsunami deposits is often difficult mainly because the tsunami deposits are represented by various sediment types, may be similar to storm deposits or altered by post-depositional processes. There is no simple universal diagnostic set of criteria that can be applied to interpret tsunami deposits with certainty. Thus, there is a need to develop new methods, which would enhance 'classical', mainly sedimentological and stratigraphic approach. The objective of the present contribution is to show recent progress and application of new approaches including geochemistry (Chagué-Goff et al. 2017) and paleogenetics (Szczuciński et al. 2016) in studies of geological impacts of recent tsunamis from various geographical regions, namely in monsoonal-tropical, temperate and polar zones. It is mainly based on own studies of coastal zones affected by 2004 Indian Ocean Tsunami in Thailand, 2011 Tohoku-oki tsunami and older paleotsunamis in Japan, catastrophic saltwater inundations at the coasts of Baltic Sea and 2000 landslide-generated tsunami in Vaigat Strait (west Greenland). The study was partly funded by Polish National Science Centre grant No. 2011/01/B/ST10/01553. Chagué-Goff C., Szczuciński W., Shinozaki T., 2017. Applications of geochemistry in tsunami research: A review. Earth-Science Reviews 165: 203-244. Szczuciński W., Pawłowska J., Lejzerowicz F

  20. The computerized semi-quantitative comprehensive identification-evaluation model for the large-sized in-situ leachable sandstone type uranium deposits in Northern Xinjiang, China

    International Nuclear Information System (INIS)

    Wang Zhengbang; Qin Mingkuan; Zhao Ruiquan; Tang Shenghuang; Wang Baoqun; Lin Shuangxing

    2001-01-01

    The process of establishment of the model includes following steps: (1) Systematically studying a known typical in-situ leachable sandstone type uranium deposit--Deposit No. 512 in Yili basin, analyzing its controlling factors and establishing its metallogenetic model; (2) Establishing the metallogenetic models of this type of uranium deposit and uranium-bearing area on the basis of comparison study on the deposit No. 512 with the same type uranium deposits in the world; (3) Creating the computerized semi-quantitative comprehensive identification-evaluation model for the large-sized in-situ leachable sandstone type uranium deposits in northern Xinjiang; (4) Determining the standards of giving a evaluation-mark for each controlling factor of in-situ leachable sandstone type uranium deposit and uranium-bearing area; (5) Evaluating uranium potential and prospect of the unknown objective target

  1. Dynamic scaling in a ballistic deposition model for a binary system

    International Nuclear Information System (INIS)

    El-Nashar, H.F.; Cerdeira, H.A.

    2000-04-01

    A ballistic deposition model for the kinetic of surface growth for two species is introduced as a description of the evolution of a surface under vapor deposition. We used a tunable parameter P to control the deposition of the particles such that one type is deposited with probability P while the other is deposited with 1 - P. Simulations in 2 + 1 dimensions using local surface diffusion lead to the formation of a rough surface whose dynamical evolution is not that of the Kardar-Parisi-Zhang universality class. Also, when surface diffusion becomes dominant, the model moves away from the Edwards-Wilkinson universality. (author)

  2. Modeling of magnetic properties of iron thin films deposited by RF magnetron sputtering using Preisach model

    Directory of Open Access Journals (Sweden)

    Bendjerad Adel

    2016-01-01

    Full Text Available Iron thin films were deposited on glass substrates using RF magnetron sputtering and their optimal deposition conditions were determined. The structure properties were analyzed using x-ray diffraction (XRD and their magnetic hysteresis loops were obtained by Vibrating Sample Magnetometer (VSM at room temperature. In this situation, the magnetic field is either parallel or perpendicular to the substrate plane. The main contribution of this work is to characterize the thin layers and present a mathematical model that can get best fit of the characteristics B(H. By using Preisach model, good agreement was obtained between theoretical and experimental results in both cases.

  3. 3D modeling of surface quarries and deposits of mined materials and the monitoring of slopes

    OpenAIRE

    Ivan Maňas

    2007-01-01

    The application of computer technology by simulating opencast mining and deposits of raw materials. The mathematic principles of three-dimensional probabilistic models of raw materials deposits and a familiarization with the user interface software GEOLOGICKY MODEL. The principles of the simulation of opencast mines, generation intersections with models of raw materials deposits, computation of mining materials with the quality scaling,and the design of advanced mining with the software BANSK...

  4. Raman microscopic studies of PVD deposited hard ceramic coatings

    International Nuclear Information System (INIS)

    Constable, C.P.

    2000-01-01

    PVD hard ceramic coatings grown via the combined cathodic arc/unbalance magnetron deposition process were studied using Raman microscopy. Characteristic spectra from binary, multicomponent, multilayered and superlattice coatings were acquired to gain knowledge of the solid-state physics associated with Raman scattering from polycrystalline PVD coatings and to compile a comprehensive spectral database. Defect-induced first order scattering mechanisms were observed which gave rise to two pronounced groups of bands related to the acoustical (150- 300cm -1 ) and optical (400-7 50cm -1 ) parts of the phonon spectrum. Evidence was gathered to support the theory that the optic modes were mainly due to the vibrations of the lighter elements and the acoustic modes due to the vibrations of the heavier elements within the lattice. A study into the deformation and disordering on the Raman spectral bands of PVD coatings was performed. TiAIN and TiZrN coatings were intentionally damaged via scratching methods. These scratches were then analysed by Raman mapping, both across and along, and a detailed spectral interpretation performed. Band broadening occurred which was related to 'phonon relaxation mechanisms' as a direct result of the breaking up of coating grains resulting in a larger proportion of grain boundaries per-unit-volume. A direct correlation of the amount of damage with band width was observed. Band shifts were also found to occur which were due to the stresses caused by the scratching process. These shifts were found to be the largest at the edges of scratches. The Raman mapping of 'droplets', a defect inherent to PVD deposition processes, found that higher compressive stresses and large amounts of disorder occurred for coating growth onto droplets. Strategies designed to evaluate the ability of Raman microscopy to monitor the extent of real wear on cutting tools were evaluated. The removal of a coating layer and subsequent detection of a base layer proved

  5. Subsidence estimation of breakwater built on loosely deposited sandy seabed foundation: Elastic model or elasto-plastic model

    Directory of Open Access Journals (Sweden)

    Jianhua Shen

    2017-07-01

    Full Text Available In offshore area, newly deposited Quaternary loose seabed soils are widely distributed. There are a great number of offshore structures has been built on them in the past, or will be built on them in the future due to the fact that there would be no very dense seabed soil foundation could be chosen at planed sites sometimes. However, loosely deposited seabed foundation would bring great risk to the service ability of offshore structures after construction. Currently, the understanding on wave-induced liquefaction mechanism in loose seabed foundation has been greatly improved; however, the recognition on the consolidation characteristics and settlement estimation of loose seabed foundation under offshore structures is still limited. In this study, taking a semi-coupled numerical model FSSI-CAS 2D as the tool, the consolidation and settlement of loosely deposited sandy seabed foundation under an offshore breakwater is investigated. The advanced soil constitutive model Pastor-Zienkiewics Mark III (PZIII is used to describe the quasi-static behavior of loose sandy seabed soil. The computational results show that PZIII model is capable of being used for settlement estimation problem of loosely deposited sandy seabed foundation. For loose sandy seabed foundation, elastic deformation is the dominant component in consolidation process. It is suggested that general elastic model is acceptable for subsidence estimation of offshore structures on loose seabed foundation; however, Young's modulus E must be dependent on the confining effective stress, rather than a constant in computation.

  6. Inverse modeling of the Chernobyl source term using atmospheric concentration and deposition measurements

    Directory of Open Access Journals (Sweden)

    N. Evangeliou

    2017-07-01

    Full Text Available This paper describes the results of an inverse modeling study for the determination of the source term of the radionuclides 134Cs, 137Cs and 131I released after the Chernobyl accident. The accident occurred on 26 April 1986 in the Former Soviet Union and released about 1019 Bq of radioactive materials that were transported as far away as the USA and Japan. Thereafter, several attempts to assess the magnitude of the emissions were made that were based on the knowledge of the core inventory and the levels of the spent fuel. More recently, when modeling tools were further developed, inverse modeling techniques were applied to the Chernobyl case for source term quantification. However, because radioactivity is a sensitive topic for the public and attracts a lot of attention, high-quality measurements, which are essential for inverse modeling, were not made available except for a few sparse activity concentration measurements far from the source and far from the main direction of the radioactive fallout. For the first time, we apply Bayesian inversion of the Chernobyl source term using not only activity concentrations but also deposition measurements from the most recent public data set. These observations refer to a data rescue attempt that started more than 10 years ago, with a final goal to provide available measurements to anyone interested. In regards to our inverse modeling results, emissions of 134Cs were estimated to be 80 PBq or 30–50 % higher than what was previously published. From the released amount of 134Cs, about 70 PBq were deposited all over Europe. Similar to 134Cs, emissions of 137Cs were estimated as 86 PBq, on the same order as previously reported results. Finally, 131I emissions of 1365 PBq were found, which are about 10 % less than the prior total releases. The inversion pushes the injection heights of the three radionuclides to higher altitudes (up to about 3 km than previously assumed (≈ 2.2 km in order

  7. Inverse modeling of the Chernobyl source term using atmospheric concentration and deposition measurements

    Science.gov (United States)

    Evangeliou, Nikolaos; Hamburger, Thomas; Cozic, Anne; Balkanski, Yves; Stohl, Andreas

    2017-07-01

    This paper describes the results of an inverse modeling study for the determination of the source term of the radionuclides 134Cs, 137Cs and 131I released after the Chernobyl accident. The accident occurred on 26 April 1986 in the Former Soviet Union and released about 1019 Bq of radioactive materials that were transported as far away as the USA and Japan. Thereafter, several attempts to assess the magnitude of the emissions were made that were based on the knowledge of the core inventory and the levels of the spent fuel. More recently, when modeling tools were further developed, inverse modeling techniques were applied to the Chernobyl case for source term quantification. However, because radioactivity is a sensitive topic for the public and attracts a lot of attention, high-quality measurements, which are essential for inverse modeling, were not made available except for a few sparse activity concentration measurements far from the source and far from the main direction of the radioactive fallout. For the first time, we apply Bayesian inversion of the Chernobyl source term using not only activity concentrations but also deposition measurements from the most recent public data set. These observations refer to a data rescue attempt that started more than 10 years ago, with a final goal to provide available measurements to anyone interested. In regards to our inverse modeling results, emissions of 134Cs were estimated to be 80 PBq or 30-50 % higher than what was previously published. From the released amount of 134Cs, about 70 PBq were deposited all over Europe. Similar to 134Cs, emissions of 137Cs were estimated as 86 PBq, on the same order as previously reported results. Finally, 131I emissions of 1365 PBq were found, which are about 10 % less than the prior total releases. The inversion pushes the injection heights of the three radionuclides to higher altitudes (up to about 3 km) than previously assumed (≈ 2.2 km) in order to better match both concentration

  8. 3D geological modeling for mineral resource assessment of the Tongshan Cu deposit, Heilongjiang Province, China

    Directory of Open Access Journals (Sweden)

    Gongwen Wang

    2012-07-01

    Full Text Available Three-dimensional geological modeling (3DGM assists geologists to quantitatively study in three-dimensional (3D space structures that define temporal and spatial relationships between geological objects. The 3D property model can also be used to infer or deduce causes of geological objects. 3DGM technology provides technical support for extraction of diverse geoscience information, 3D modeling, and quantitative calculation of mineral resources. Based on metallogenic concepts and an ore deposit model, 3DGM technology is applied to analyze geological characteristics of the Tongshan Cu deposit in order to define a metallogenic model and develop a virtual borehole technology; a BP neural network and a 3D interpolation technique were combined to integrate multiple geoscience information in a 3D environment. The results indicate: (1 on basis of the concept of magmatic-hydrothermal Cu polymetallic mineralization and a porphyry Cu deposit model, a spatial relational database of multiple geoscience information for mineralization in the study area (geology, geophysics, geochemistry, borehole, and cross-section data was established, and 3D metallogenic geological objects including mineralization stratum, granodiorite, alteration rock, and magnetic anomaly were constructed; (2 on basis of the 3D ore deposit model, 23,800 effective surveys from 94 boreholes and 21 sections were applied to establish 3D orebody models with a kriging interpolation method; (3 combined 23,800 surveys involving 21 sections, using VC++ and OpenGL platform, virtual borehole and virtual section with BP network, and an improved inverse distance interpolation (IDW method were used to predict and delineate mineralization potential targets (Cu-grade of cell not less than 0.1%; (4 comparison of 3D ore bodies, metallogenic geological objects of mineralization, and potential targets of mineralization models in the study area, delineated the 3D spatial and temporal relationship and causal

  9. Cloud diagnosis impact on deposition modelling applied to the Fukushima accident

    Science.gov (United States)

    Quérel, Arnaud; Quélo, Denis; Roustan, Yelva; Mathieu, Anne

    2017-04-01

    The accident at the Fukushima Daiichi Nuclear Power Plant in Japan in March 2011 resulted in the release of several hundred PBq of activity into the environment. Most of the radioactivity was released in a time period of about 40 days. Radioactivity was dispersed in the atmosphere and the ocean and subsequently traces of radionuclides were detected all over Japan. At the Fukushima airport for instance, a deposit as large as 36 kBq/m2 of Cs-137 was measured resulting of an atmospheric deposition of the plume. Both dry and wet deposition were probably involved since a raining event occurred on the 15th of March when the plume was passing nearby. The accident scenario have given rise to a number of scientific investigations. Atmospheric deposition, for example, was studied by utilizing atmospheric transport models. In atmospheric transport models, some parameters, such as cloud diagnosis, are derived from meteorological data. This cloud diagnosis is a key issue for wet deposition modelling since it allows to distinguish between two processes: in-cloud scavenging which corresponds to the collection of radioactive particles into the cloud and below-cloud scavenging consequent to the removal of radioactive material due to the falling drops. Several parametrizations of cloud diagnosis exist in the literature, using different input data: relative humidity, liquid water content, also. All these diagnosis return a large range of cloud base heights and cloud top heights. In this study, computed cloud diagnostics are compared to the observations at the Fukushima airport. Atmospheric dispersion simulations at Japan scale are then performed utilizing the most reliable ones. Impact on results are discussed.

  10. Modelled transport and deposition of sulphur over Southern Africa

    CSIR Research Space (South Africa)

    Zunckel, M

    2000-01-01

    Full Text Available province, and the remote site at Ben MacDhui. and plant physiology to infer the deposition velocity. As a result, the inferred deposition velocity takes daily and seasonal meteorological and plant physiological vari- ations into account. On summer days over...

  11. Study of lead isotopes for investigating the origin of endogenic deposits with special reference to some ore deposits from India

    International Nuclear Information System (INIS)

    Chernyshev, I.V.; Safonov, Yu. G.; Radhakrishna, B.P.; Vasudev, V.N.; Krishna Rao, B.; Deb, M.

    1980-01-01

    The isotope composition of leads from ore deposits in general reflects the age of ore mineralisation and its genetical features. Calculations of the model age from lead isotope data form the basis for genetic reconstructions of Precambrain deposits. Radical improvement in the accuracy of mass spectrometric isotope lead analysis has made possible the employment of two-stage and in some cases more complicated models for genetic reconstructions. Fifteen galena samples from five sulphide and gold-sulphide deposits of the Indian Shield have been selected and determination of lead isotope composition has been carried out in the USSR using recently developed M.I.1320 Mass Spectrometer. The isotopic ratios of galena from Ingaldhal copper deposit are the most primitive among the analysed ores of the Indian Shield. The results of lead isotopic determination have been interpreted in terms of the general theory of 'plumbotectonics'. (auth.)

  12. Study of hydrogeological and engineering-geological conditions of deposits

    International Nuclear Information System (INIS)

    1985-01-01

    Methods for hydrogeological and engineering-geological studies are considered as a part of the complex works dUring eXploration of hydrogenic uranium deposits to develop them by Underground ieaching (UL). Problems are enumerated and peculiarities Of hydrogeologic and engipeering-geological works at different stages are outlined (prospeccing - evaluating works, preliminary and detailed survey). Attention is paid to boring and equipment for hydrogeological and engineering - geological boreholes. Testing-filtering works are described, the latter includes: evacuations, fulnesses ( forcings), and tests of fulness-evacuation. The problem on steady-state observations in boreholes and laboratory studies of rocks and underground waters is discussed. Geological and geophysical methods for evaluation of rock and ore filtering properties are presented. Necessity of hydrogeological zonation of deposits as applied to UL is marked

  13. Kinetic Study of the Chemical Vapor Deposition of Tantalum in Long Narrow Channels

    DEFF Research Database (Denmark)

    Mugabi, James Atwoki; Eriksen, Søren; Petrushina, Irina

    2016-01-01

    A kinetic study of the chemical vapor deposition of tantalum in long narrow channels is done to optimize the industrial process for the manufacture of tantalum coated plate heat exchangers. The developed model fits well at temperatures between 750 and 850 °C, and in the pressure range of25–990 mbar...

  14. Investigation of Properties of Nanocomposite Polyimide Samples Obtained by Fused Deposition Modeling

    Science.gov (United States)

    Polyakov, I. V.; Vaganov, G. V.; Yudin, V. E.; Ivan'kova, E. M.; Popova, E. N.; Elokhovskii, V. Yu.

    2018-03-01

    Nanomodified polyimide samples were obtained by fused deposition modeling (FDM) using an experimental setup for 3D printing of highly heat-resistant plastics. The mechanical properties and structure of these samples were studied by viscosimetry, differential scanning calorimetry, and scanning electron microscopy. A comparative estimation of the mechanical properties of laboratory samples obtained from a nanocomposite based on heat-resistant polyetherimide by FDM and injection molding is presented.

  15. Mechanistic Study on the Degradation of Thermal Barrier Coatings Induced by Volcanic Ash Deposition

    Science.gov (United States)

    Arai, Masayuki

    2017-08-01

    Thermal stress generated on thermal barrier coatings (TBCs) by volcanic ash (VA) deposition was assessed measuring the tip deflection of a multilayered beam structure as a function of temperature. The TBC in this study was deposited onto the surface of a blade utilized in a land-based gas turbine which is composed of 8 wt.%Y2O3-ZrO2/CoNiCrAlY on a Ni-based superalloy. The VA-deposited TBC sample was heated at 1453 K, and the effect of VA deposition on TBC delamination was examined in comparison with a TBC sample without VA deposition as a reference. On the basis of the VA attack damage mechanism which was investigated via the tip deflection measurement and a comprehensive microstructure examination, a damage-coupled constitutive model was proposed. The proposed model was based on the infiltration of the molten VA inside pores and phase transformations of yttria -tabilized zirconia in the TBC system. The numerical analysis results, which were simulated utilizing the finite element code installing the developed constitutive model, showed us that VA attack on the TBC sample induced near-interfacial cracks because of a significant increasing in the coating stress.

  16. Modeling and control of diffusion and low-pressure chemical vapor deposition furnaces

    Science.gov (United States)

    De Waard, H.; De Koning, W. L.

    1990-03-01

    In this paper a study is made of the heat transfer inside cylindrical resistance diffusion and low-pressure chemical vapor deposition furnaces, aimed at developing an improved temperature controller. A model of the thermal behavior is derived which also covers the important class of furnaces equipped with semitransparent quartz process tubes. The model takes into account the thermal behavior of the thermocouples. It is shown that currently used temperature controllers are highly inefficient for very large scale integration applications. Based on the model an alternative temperature controller of the linear-quadratic-Gaussian type is proposed which features direct wafer temperature control. Some simulation results are given.

  17. Geology and Mineralogy of Uranium Deposits from Mount Isa, Australia: Implications for Albitite Uranium Deposit Models

    Directory of Open Access Journals (Sweden)

    Nick Wilson

    2013-06-01

    Full Text Available New geological, bulk chemical and mineralogical (QEMSCAN and FEG-EPMA data are presented for albitite-type uranium deposits of the Mount Isa region of Queensland, Australia. Early albitisation of interbedded metabasalt and metasiltstone predated intense deformation along D2 high strain (mylonite zones. The early sodic alteration paragenetic stage includes albite, riebeckite, aegirine, apatite, zircon and magnetite. This paragenetic stage was overprinted by potassic microveins, containing K-feldspar, biotite, coffinite, brannerite, rare uraninite, ilmenite and rutile. An unusual U-Zr phase has also been identified which exhibits continuous solid solution with a uranium silicate possibly coffinite or nenadkevite. Calcite, epidote and sulphide veinlets represent the latest stage of mineralisation. This transition from ductile deformation and sodic alteration to vein-controlled uranium is mirrored in other examples of the deposit type. The association of uranium with F-rich minerals and a suite of high field strength elements; phosphorous and zirconium is interpreted to be indicative of a magmatic rather than metamorphic or basinal fluid source. No large intrusions of appropriate age outcrop near the deposits; but we suggest a relationship with B- and Be-rich pegmatites and quartz-tourmaline veins.

  18. Laser Energy Deposition Model for the ICF3D Code

    Science.gov (United States)

    Kaiser, Thomas B.; Byers, Jack A.

    1996-11-01

    We have built a laser deposition module for the new ICF physics design code, ICF3D(``3D Unstructured Mesh ALE Hydrodynamics with the Upwind Discontinuous Finite Element Method,'' D. S. Kershaw, M. K. Prasad and M. J. Shaw,'' LLNL Report UCRL-JC-122104, (1995)), being developed at LLNL. The code uses a 3D unstructured grid on which hydrodynamic quantities are represented in terms of discontinuous linear finite elements (hexahedrons, prisms, tetrahedrons or pyramids). Because of the complex mesh geometry and (in general) non-uniform index of refraction (i.e., plasma density), the geometrical-optical ray-tracing problem is quite complicated. To solve it we have developed a grid-cell-face-crossing detection algorithm, an integrator for the ray equations of motion and a path-length calculator that are encapsulated in a C++ class that is used to create ray-bundle objects. Additional classes are being developed for inverse-bremsstrahlung and resonance-absorption heating models. A quasi-optical technique will be used to include diffractive effects. We use the ICF3D Python shell, a very flexible interface that allows command-line invocation of member functions.

  19. Plasticized protein for 3D printing by fused deposition modeling

    Science.gov (United States)

    Chaunier, Laurent; Leroy, Eric; Della Valle, Guy; Lourdin, Denis

    2016-10-01

    The developments of Additive Manufacturing (AM) by Fused Deposition Modeling (FDM) now target new 3D printable materials, leading to novel properties like those given by biopolymers such as proteins: degradability, biocompatibility and edibility. Plasticized materials from zein, a storage protein issued from corn, present interesting thermomechanical and rheological properties, possibly matching with AM-FDM specifications. Thus commercial zein plasticized with 20% glycerol has a glass transition temperature (Tg) at about 42°C, after storage at intermediate relative humidity (RH=59%). Its principal mechanical relaxation at Tα ≈ 50°C leads to a drop of the elastic modulus from about 1.1 GPa, at ambient temperature, to 0.6 MPa at Tα+100°C. These values are in the same range as values obtained in the case of standard polymers for AM-FDM processing, as PLA and ABS, although relaxation mechanisms are likely different in these materials. Such results lead to the setting up of zein-based compositions printable by AM-FDM and allow processing bioresorbable printed parts, with designed 3D geometry and structure.

  20. Interdiffusion of Polycarbonate in Fused Deposition Modeling Welds

    Science.gov (United States)

    Seppala, Jonathan; Forster, Aaron; Satija, Sushil; Jones, Ronald; Migler, Kalman

    2015-03-01

    Fused deposition modeling (FDM), a now common and inexpensive additive manufacturing method, produces 3D objects by extruding molten polymer layer-by-layer. Compared to traditional polymer processing methods (injection, vacuum, and blow molding), FDM parts have inferior mechanical properties, surface finish, and dimensional stability. From a polymer processing point of view the polymer-polymer weld between each layer limits the mechanical strength of the final part. Unlike traditional processing methods, where the polymer is uniformly melted and entangled, FDM welds are typically weaker due to the short time available for polymer interdiffusion and entanglement. To emulate the FDM process thin film bilayers of polycarbonate/d-polycarbonate were annealed using scaled times and temperatures accessible in FDM. Shift factors from Time-Temperature Superposition, measured by small amplitude oscillatory shear, were used to calculate reasonable annealing times (min) at temperatures below the actual extrusion temperature. The extent of interdiffusion was then measured using neutron reflectivity. Analogous specimens were prepared to characterize the mechanical properties. FDM build parameters were then related to interdiffusion between welded layers and mechanical properties. Understating the relationship between build parameters, interdiffusion, and mechanical strength will allow FDM users to print stronger parts in an intelligent manner rather than using trial-and-error and build parameter lock-in.

  1. Modeled subalpine plant community response to climate change and atmospheric nitrogen deposition in Rocky Mountain National Park, USA

    International Nuclear Information System (INIS)

    McDonnell, T.C.; Belyazid, S.; Sullivan, T.J.; Sverdrup, H.; Bowman, W.D.; Porter, E.M.

    2014-01-01

    To evaluate potential long-term effects of climate change and atmospheric nitrogen (N) deposition on subalpine ecosystems, the coupled biogeochemical and vegetation community competition model ForSAFE-Veg was applied to a site at the Loch Vale watershed of Rocky Mountain National Park, Colorado. Changes in climate and N deposition since 1900 resulted in pronounced changes in simulated plant species cover as compared with ambient and estimated future community composition. The estimated critical load (CL) of N deposition to protect against an average future (2010–2100) change in biodiversity of 10% was between 1.9 and 3.5 kg N ha −1  yr −1 . Results suggest that the CL has been exceeded and vegetation at the study site has already undergone a change of more than 10% as a result of N deposition. Future increases in air temperature are forecast to cause further changes in plant community composition, exacerbating changes in response to N deposition alone. - Highlights: • A novel calibration step was introduced for modeling biodiversity with ForSAFE-Veg. • Modeled increases in tree cover are consistent with empirical studies. • Reductions in N deposition decreased future graminoid percent cover. • Critical loads of N to protect biodiversity should consider climate change effects. - Subalpine plant biodiversity in Rocky Mountain National Park has already been impacted by N deposition and climate change and is expected to experience significant future effects

  2. Computational model for microstructure and effective thermal conductivity of ash deposits in utility boilers

    Science.gov (United States)

    Kweon, Soon-Cheol

    The ash deposits formed in pulverized-coal fired power plants reduce heat transfer rate to furnace wall, super heater tubes, and other heat transfer surfaces. The thermal properties that influence strongly on this heat transfer depend mainly on the microstructure of the ash deposit. This dissertation examines three issues associated with the ash deposits in utility boilers: (1) the three-dimensional model for characterization of the ash deposit microstructures from the sample ash deposits, (2) the computational model for effective thermal conductivity of sintered packed beds with low conductive stagnant fluids, and (3) the application of thermal resistor network model for the effective thermal conductivity of ash deposits in utility boilers. The SEM image analysis was conducted on two sample ash deposits to characterize three-dimensional microstructure of the ash deposit with several structural parameters using stereology. A ballistic deposition model was adopted to simulate the deposit structure defined by the structural parameters. The inputs for the deposition model were chosen from the predicted and measured physical parameters, such as the size distribution, the probability of the particle rolling, and the degree of the particle sintering. The difference between the microstructure of the sample deposits and the simulated deposits was investigated and compared quantitatively based on the structural parameters defined. Both the sample and the simulated deposits agree in terms of the structural parameters. The computational model for predicting the effective thermal conductivity of sintered packed beds with low conductive stagnant fluid was built and the heat conduction through the contact area among sintered particles is the dominant mode of heat transfer. A thermal resistor network is used to model the heat conduction among the sintered particles and the thermal resistance among the contacting particles is estimated from both the contact area and the contact

  3. Model for transfer of cesium and strontium to domestic animal products as a consequence of accidental deposition on ground

    International Nuclear Information System (INIS)

    Suolanen, V.

    1994-02-01

    In the study the contamination of domestic animal products (milk, beef, pork) and grain is predicted applying a compartment model approach to simulate the dynamic behaviour of radionuclides in the biosphere after an accidental atmospheric deposition. Further, the radionuclide intakes into human body by consumption of the contaminated domestic animal products and the arising internal doses, are studied. The contamination of domestic animal products and grain are predicted by considering three representative deposition cases. The considered deposition timepoints are: spring (1st of May), summer (1st of July) and autumn (1st of September). The nuclides considered are 137 Cs, 134 Cs and 90 Sr. (18 refs., 14 figs., 8 tabs.)

  4. A computational study of odorant transport and deposition in the canine nasal cavity: implications for olfaction.

    Science.gov (United States)

    Lawson, M J; Craven, B A; Paterson, E G; Settles, G S

    2012-07-01

    Olfaction begins when an animal draws odorant-laden air into its nasal cavity by sniffing, thus transporting odorant molecules from the external environment to olfactory receptor neurons (ORNs) in the sensory region of the nose. In the dog and other macrosmatic mammals, ORNs are relegated to a recess in the rear of the nasal cavity that is comprised of a labyrinth of scroll-like airways. Evidence from recent studies suggests that nasal airflow patterns enhance olfactory sensitivity by efficiently delivering odorant molecules to the olfactory recess. Here, we simulate odorant transport and deposition during steady inspiration in an anatomically correct reconstructed model of the canine nasal cavity. Our simulations show that highly soluble odorants are deposited in the front of the olfactory recess along the dorsal meatus and nasal septum, whereas moderately soluble and insoluble odorants are more uniformly deposited throughout the entire olfactory recess. These results demonstrate that odorant deposition patterns correspond with the anatomical organization of ORNs in the olfactory recess. Specifically, ORNs that are sensitive to a particular class of odorants are located in regions where that class of odorants is deposited. The correlation of odorant deposition patterns with the anatomical organization of ORNs may partially explain macrosmia in the dog and other keen-scented species.

  5. Computational Modelling of a Tangentially Fired Boiler With Deposit Formation Phenomena

    OpenAIRE

    Modliński Norbert J.

    2014-01-01

    Any complete CFD model of pulverised coal-fired boiler needs to consider ash deposition phenomena. Wall boundary conditions (temperature and emissivity) should be temporally corrected to account for the effects of deposit growth on the combustion conditions. At present voluminous publications concerning ash related problems are available. The current paper presents development of an engineering tool integrating deposit formation models with the CFD code. It was then applied to two tangentiall...

  6. Experimental study on the particles deposition in the sampling duct

    Energy Technology Data Exchange (ETDEWEB)

    Vendel, J.; Charuau, J. [Institut de Protection et de Surete Nucleaire, Yvette (France)

    1995-02-01

    A high standard of protection against the harmful effects of radioactive aerosol dissemination requires a measurement, as representative as possible, of their concentration. This measurement depends on the techniques used for aerosol sampling and transfer to the detector, as well as on the location of the latter with respect to the potential sources. The aeraulic design of the apparatus is also an important factor. Once collected the aerosol particles often have to travel through a variably shaped duct to the measurement apparatus. This transport is responsible for losses due to the particles deposition on the walls, leading to a distortion on the concentration measurements and a change in the particle size distribution. To estimate and minimize measurement errors it is important to determine the optimal transport conditions when designing a duct; its diameter and material, the radius of curvature of the bends and the flow conditions must be defined in particular. This paper presents an experimental study in order to determine, for each deposition mechanism, the retained fraction, or the deposition velocity for different flow regimes. This study has pointed out that it exists a favourable flow regime for the particle transport through the sampling ducts (2 500 < Re < 5 000). It has been established, for any particle diameters, equations to predict the aerosol penetration in smooth-walled cylindrical metal ducts.

  7. Experimental study on the particles deposition in the sampling duct

    International Nuclear Information System (INIS)

    Vendel, J.; Charuau, J.

    1995-01-01

    A high standard of protection against the harmful effects of radioactive aerosol dissemination requires a measurement, as representative as possible, of their concentration. This measurement depends on the techniques used for aerosol sampling and transfer to the detector, as well as on the location of the latter with respect to the potential sources. The aeraulic design of the apparatus is also an important factor. Once collected the aerosol particles often have to travel through a variably shaped duct to the measurement apparatus. This transport is responsible for losses due to the particles deposition on the walls, leading to a distortion on the concentration measurements and a change in the particle size distribution. To estimate and minimize measurement errors it is important to determine the optimal transport conditions when designing a duct; its diameter and material, the radius of curvature of the bends and the flow conditions must be defined in particular. This paper presents an experimental study in order to determine, for each deposition mechanism, the retained fraction, or the deposition velocity for different flow regimes. This study has pointed out that it exists a favourable flow regime for the particle transport through the sampling ducts (2 500 < Re < 5 000). It has been established, for any particle diameters, equations to predict the aerosol penetration in smooth-walled cylindrical metal ducts

  8. Characterization, modeling and simulation of fused deposition modeling fabricated part surfaces

    Science.gov (United States)

    Taufik, Mohammad; Jain, Prashant K.

    2017-12-01

    Surface roughness is generally used for characterization, modeling and simulation of fused deposition modeling (FDM) fabricated part surfaces. But the average surface roughness is not able to provide the insight of surface characteristics with sharp peaks and deep valleys. It deals in the average sense for all types of surfaces, including FDM fabricated surfaces with distinct surface profile features. The present research work shows that kurtosis and skewness can be used for characterization, modeling and simulation of FDM surfaces because these roughness parameters have the ability to characterize a surface with sharp peaks and deep valleys. It can be critical in certain application areas in tribology and biomedicine, where the surface profile plays an important role. Thus, in this study along with surface roughness, skewness and kurtosis are considered to show a novel strategy to provide new transferable knowledge about FDM fabricated part surfaces. The results suggest that the surface roughness, skewness and kurtosis are significantly different at 0° and in the range (0°, 30°], [30°, 90°] of build orientation.

  9. INFLUENCE OF PROCESS PARAMETERS ON DIMENSIONAL ACCURACY OF PARTS MANUFACTURED USING FUSED DEPOSITION MODELLING TECHNOLOGY

    Directory of Open Access Journals (Sweden)

    Filip Górski

    2013-09-01

    Full Text Available The paper presents the results of experimental study – part of research of additive technology using thermoplastics as a build material, namely Fused Deposition Modelling (FDM. Aim of the study was to identify the relation between basic parameter of the FDM process – model orientation during manufacturing – and a dimensional accuracy and repeatability of obtained products. A set of samples was prepared – they were manufactured with variable process parameters and they were measured using 3D scanner. Significant differences in accuracy of products of the same geometry, but manufactured with different set of process parameters were observed.

  10. Sediment Deposition Risk Analysis and PLSR Model Research for Cascade Reservoirs Upstream of the Yellow River

    Directory of Open Access Journals (Sweden)

    Jie Yang

    2015-01-01

    Full Text Available It is difficult to effectively identify and eliminate the multiple correlation influence among the independent factors by least-squares regression. Focusing on this insufficiency, the sediment deposition risk of cascade reservoirs and fitting model of sediment flux into the reservoir are studied. The partial least-squares regression (PLSR method is adopted for modeling analysis; the model fitting is organically combined with the non-model-style data content analysis, so as to realize the regression model, data structure simplification, and multiple correlations analysis among factors; meanwhile the accuracy of the model is ensured through cross validity check. The modeling analysis of sediment flux into the cascade reservoirs of Long-Liu section upstream of the Yellow River indicates that partial least-squares regression can effectively overcome the multiple correlation influence among factors, and the isolated factor variables have better ability to explain the physical cause of measured results.

  11. Validating modelled data on major and trace element deposition in southern Germany using Sphagnum moss

    Science.gov (United States)

    Kempter, Heike; Krachler, Michael; Shotyk, William; Zaccone, Claudio

    2017-10-01

    Sphagnum mosses were collected from four ombrotrophic bogs in two regions of southern Germany: Upper Bavaria (Oberbayern, OB) and the Northern Black Forest (Nordschwarzwald, NBF). Surfaces of Sphagnum carpets were marked with plastic mesh and, one year later, plant matter was harvested and productivity determined. Major and trace element concentrations (Ag, Al, As, Ba, Bi, Cd, Co, Cr, Cu, Fe, Mn, Mo, Pb, Rb, Sb, Sc, Sr, Th, Ti, Tl, U, V, Zn) were determined in acid digests using sector field ICP-MS. Up to 12 samples (40 × 40 cm) were collected per site, and 6-10 sites investigated per bog. Variation in element accumulation rates within a bog is mostly the result of the annual production rate of the Sphagnum mosses which masks not only the impact of site effects, such as microtopography and the presence of dwarf trees, but also local and regional conditions, including land use in the surrounding area, topography, etc. The difference in productivity between peat bogs results in distinctly higher element accumulation rates at the NBF bogs compared to those from OB for all studied elements. The comparison with the European Monitoring and Evaluation Program (EMEP; wet-only and total deposition) and Modelling of Air Pollutants and Ecosystem Impact (MAPESI; total deposition) data shows that accumulation rates obtained using Sphagnum are in the same range of published values for direct measurements of atmospheric deposition of As, Cd, Cu, Co, Pb, and V in both regions. The accordance is very dependent on how atmospheric deposition rates were obtained, as different models to calculate the deposition rates may yield different fluxes even for the same region. In future studies of atmospheric deposition of trace metals, both Sphagnum moss and deposition collectors have to be used on the same peat bog and results compared. Antimony, however, shows considerable discrepancy, because it is either under-estimated by Sphagnum moss or over-estimated by both atmospheric deposition

  12. Some Causative Factors in Bank Deposit Supply Model in Nigeria: A ...

    African Journals Online (AJOL)

    In this study, we examined some of the factors that influence the commercial bank deposit supply behaviour in Nigeria. Specifically, we examined the impact of deposit interest rate, foreign exchange rate, Treasury bill rate and Growth rate of Gross Domestic Product on the deposit output behaviour of commercial banks.

  13. The OML-SprayDrift model for predicting pesticide drift and deposition from ground boom sprayers

    DEFF Research Database (Denmark)

    Løfstrøm, Per; Bruus, Marianne; Andersen, Helle Vibeke

    2013-01-01

    In order to predict the exposure of hedgerows and other neighboring biotopes to pesticides from field-spray applications, an existing Gaussian atmospheric dispersion and deposition model was developed to model the changes in droplet size due to evaporation affecting the deposition velocity. The G...

  14. Critique of the use of deposition velocity in modeling indoor air quality

    International Nuclear Information System (INIS)

    Nazaroff, W.W.; Weschler, C.J.

    1993-01-01

    Among the potential fates of indoor air pollutants are a variety of physical and chemical interactions with indoor surfaces. In deterministic mathematical models of indoor air quality, these interactions are usually represented as a first-order loss process, with the loss rate coefficient given as the product of the surface-to-volume ratio of the room times a deposition velocity. In this paper, the validity of this representation of surface-loss mechanisms is critically evaluated. From a theoretical perspective, the idea of a deposition velocity is consistent with the following representation of an indoor air environment. Pollutants are well-mixed throughout a core region which is separated from room surfaces by boundary layers. Pollutants migrate through the boundary layers by a combination of diffusion (random motion resulting from collisions with surrounding gas molecules), advection (transport by net motion of the fluid), and, in some cases, other transport mechanisms. The rate of pollutant loss to a surface is governed by a combination of the rate of transport through the boundary layer and the rate of reaction at the surface. The deposition velocity expresses the pollutant flux density (mass or moles deposited per area per time) to the surface divided by the pollutant concentration in the core region. This concept has substantial value to the extent that the flux density is proportional to core concentration. Published results from experimental and modeling studies of fine particles, radon decay products, ozone, and nitrogen oxides are used as illustrations of both the strengths and weaknesses of deposition velocity as a parameter to indicate the rate of indoor air pollutant loss on surfaces. 66 refs., 5 tabs

  15. Rheological characterization of plasticized corn proteins for fused deposition modeling

    Science.gov (United States)

    Chaunier, Laurent; Dalgalarrondo, Michèle; Della Valle, Guy; Lourdin, Denis; Marion, Didier; Leroy, Eric

    2017-10-01

    Additive Manufacturing (AM) of tailored natural biopolymer-based objects by Fused Deposition Modeling (FDM) opens new perspectives for applications such as biomedical temporary devices, or pharmaceutical tablets. This exploits the biocompatibility, resorbability and edibility properties of biopolymers. When adequately plasticized, zeins, storage proteins from endosperm of maize kernels, displayed thermomechanical properties possibly matching FDM processing requirements at a convenient temperature Tprinting=130°C. Indeed, with 20% glycerol added (Tg=42°C), plasticized zeins present a high modulus, E'>1GPa, at ambient conditions, which drops below 0.6 MPa at the processing temperature T=130°C, before flowing in the molten state. The rheological characterization shows that the processing window is limited by a progressive increase of viscosity linked to proteins aggregation and crosslinking by S-S bonding between cysteine amino acid residues, which can lead to gelation. However, for short residence time typical of FDM, the viscosity of plasticized zeins is comparable to the one of standard polymers, like ABS or PLA in their FDM processing conditions: indeed, in presence of glycerol, the molten zeins show a shear-thinning behavior with |η*|≈3kPa.s at 1s-1, decreasing to |η*|≈0.3kPa.s at 100s-1, at 130°C. Moreover, zeins presenting both hydrophilic and hydrophobic domains, amphiphilic plasticizers can be used supplementary to tune their rheological behavior. With 20% oleic acid added to the previous composition, the viscosity is divided down to a ratio about 1/2 at 100s-1 at 130°C, below the value of a standard polymer as PLA at its printing temperature. These results show the possible enhancement of the printability of zein-based materials in the molten state, by combining polar and amphiphilic plasticizers.

  16. Studies of Physicochemical Processes in Atmospheric Particles and Acid Deposition.

    Science.gov (United States)

    Pandis, Spyros N.

    A comprehensive chemical mechanism for aqueous -phase atmospheric chemistry was developed and its detailed sensitivity analysis was performed. The main aqueous-phase reaction pathways for the system are the oxidation of S(IV) to S(VI) by H_2O_2 , OH, O_2 (catalysed by Fe ^{3+} and Mn^ {2+}), O_3 and HSO_sp{5}{-}. The gas-phase concentrations of SO_2, H_2O_2, HO _2, OH, O_3 HCHO, NH_3, HNO_3 and HCl and the liquid water content of the cloud are of primary importance. The Lagrangian model predictions for temperature profile, fog development, liquid water content, gas-phase concentrations of SO_2 , HNO_3, and NH_3 , pH, aqueous-phase concentrations of SO _sp{4}{2-}, NH _sp{4}{+} and NO _sp{3}{-}, and finally deposition rates of the above ions match well the observed values. A third model was developed to study the distribution of acidity and solute concentration among the various droplet sizes in a fog or a cloud. Significant solute concentration differences can occur in aqueous droplets inside a fog or a cloud. Fogs in polluted environments have the potential to increase aerosol sulfate concentrations, but at the same time to cause reductions in the aerosol concentration of nitrate, chloride, ammonium and sodium as well as in the total aerosol mass concentration. The sulfate producd during fog episodes favors the aerosol particles that have access to most of the fog liquid water. Aerosol scavenging efficiencies of around 80% were calculated for urban fogs. Sampling and subsequent mixing of fog droplets of different sizes may result in measured concentrations that are not fully representative of the fogwater chemical composition. Isoprene and beta-pinene, at concentration levels ranging from a few ppb to a few ppm were reacted photochemically with NO_ {x} in the Caltech outdoor smog chamber facility. Aerosol formation from the isoprene photooxidation was found to be negligible even under extreme ambient conditions due to the relatively high vapor pressure of its

  17. Solar Energy Deposition Rates in the Mesosphere Derived from Airglow Measurements: Implications for the Ozone Model Deficit Problem

    Science.gov (United States)

    Mlynczak, Martin G.; Garcia, Rolando R.; Roble, Raymond G.; Hagan, Maura

    2000-01-01

    We derive rates of energy deposition in the mesosphere due to the absorption of solar ultraviolet radiation by ozone. The rates are derived directly from measurements of the 1.27-microns oxygen dayglow emission, independent of knowledge of the ozone abundance, the ozone absorption cross sections, and the ultraviolet solar irradiance in the ozone Hartley band. Fifty-six months of airglow data taken between 1982 and 1986 by the near-infrared spectrometer on the Solar-Mesosphere Explorer satellite are analyzed. The energy deposition rates exhibit altitude-dependent annual and semi-annual variations. We also find a positive correlation between temperatures and energy deposition rates near 90 km at low latitudes. This correlation is largely due to the semiannual oscillation in temperature and ozone and is consistent with model calculations. There is also a suggestion of possible tidal enhancement of this correlation based on recent theoretical and observational analyses. The airglow-derived rates of energy deposition are then compared with those computed by multidimensional numerical models. The observed and modeled deposition rates typically agree to within 20%. This agreement in energy deposition rates implies the same agreement exists between measured and modeled ozone volume mixing ratios in the mesosphere. Only in the upper mesosphere at midlatitudes during winter do we derive energy deposition rates (and hence ozone mixing ratios) consistently and significantly larger than the model calculations. This result is contrary to previous studies that have shown a large model deficit in the ozone abundance throughout the mesosphere. The climatology of solar energy deposition and heating presented in this paper is available to the community at the Middle Atmosphere Energy Budget Project web site at http://heat-budget.gats-inc.com.

  18. Depositional sequence analysis and sedimentologic modeling for improved prediction of Pennsylvanian reservoirs (Annex 1)

    Energy Technology Data Exchange (ETDEWEB)

    Watney, W.L.

    1992-01-01

    Interdisciplinary studies of the Upper Pennsylvanian Lansing and Kansas City groups have been undertaken in order to improve the geologic characterization of petroleum reservoirs and to develop a quantitative understanding of the processes responsible for formation of associated depositional sequences. To this end, concepts and methods of sequence stratigraphy are being used to define and interpret the three-dimensional depositional framework of the Kansas City Group. The investigation includes characterization of reservoir rocks in oil fields in western Kansas, description of analog equivalents in near-surface and surface sites in southeastern Kansas, and construction of regional structural and stratigraphic framework to link the site specific studies. Geologic inverse and simulation models are being developed to integrate quantitative estimates of controls on sedimentation to produce reconstructions of reservoir-bearing strata in an attempt to enhance our ability to predict reservoir characteristics.

  19. Magma Emplacement Rates and Porphyry Copper Deposits: Thermal Modelling of the Yerington Batholith, Nevada, USA

    Science.gov (United States)

    Schöpa, Anne; Annen, Catherine; Dilles, John H.; Sparks, R. Stephen J.; Blundy, Jon D.

    2017-04-01

    Many porphyry copper deposits are associated with granitoid plutons. Their genesis is attributed to the degassing of pluton-forming intermediate to silicic magma chambers. These plutons are commonly envisioned as resulting from the slow cooling and crystallization of large magma chambers. Most of the models combine the formation of ore deposits and the cooling of a magma chamber. However, they do not consider neither how typically hundreds of cubic kilometres of magma were emplaced into the upper crust, nor the prolonged growth of plutons involving simultaneous cooling and crystallization together with the release of exsolved volatiles, which may contribute to ore formation. We use numerical simulations of thermal evolution due to pluton growth to investigate the links between pluton construction, magma accumulation, solidification, volatile exsolution, volatile release and porphyry copper formation. The Jurassic Yerington batholith in western Nevada, USA, is used as a case study because it is associated with economic porphyry copper deposits, it shows an exceptional exposure revealing the geometry of the intrusion, and petrological and geochronological analysis have shed light on its emplacement style and duration. Our conductive heat flow model simulates the growth of the ˜1000 km3 batholith emplaced at 2-8 km crustal depth by step-wise intrusions of vertically stacked sills. Different emplacement rates and repose times of no melt injection between the three main Yerington intrusions were tested. Our numerical simulations show that to comply with the conceptual model linking porphyry copper deposits with the presence of large, highly molten magma chambers, magmas must be emplaced at a high rate of several cm/yr. In plutonic records, such high rates are uncommon. It follows that either the current conceptual model is incorrect or that porphyry copper deposits are only produced by the rare, rapidly emplaced plutons. The fact that many granitoid plutons are barren

  20. A deposit model for carbonatite and peralkaline intrusion-related rare earth element deposits: Chapter J in Mineral deposit models for resource assessment

    Science.gov (United States)

    Verplanck, Philip L.; Van Gosen, Bradley S.; Seal, Robert R.; McCafferty, Anne E.

    2014-01-01

    Carbonatite and alkaline intrusive complexes, as well as their weathering products, are the primary sources of rare earth elements. A wide variety of other commodities have been exploited from carbonatites and alkaline igneous rocks including niobium, phosphate, titanium, vermiculite, barite, fluorite, copper, calcite, and zirconium. Other elements enriched in these deposits include manganese, strontium, tantalum, thorium, vanadium, and uranium. Carbonatite and peralkaline intrusion-related rare earth element deposits are presented together in this report because of the spatial, and potentially genetic, association between carbonatite and alkaline rocks. Although these rock types occur together at many locations, carbonatite and peralkaline intrusion-related rare earth element deposits are not generally found together.

  1. Application of fused deposition modeling rapid prototyping system to the development of microchannels

    Science.gov (United States)

    Wang, Hengzi; Masood, Syed; Iovenitti, Pio; Harvey, Erol C.

    2001-11-01

    Conventional methods of producing micro-scale components for BioMEMS applications such as microfluidic devices are limited to relatively simple geometries and are inefficient for prototype production. Rapid prototyping techniques may be applied to overcome these limitations. Fused Deposition Modelling is one such rapid prototyping process, which can build parts using layer by layer deposition technique with layers as low as 0.178 mm thick and using a select group of thermoplastic building materials. This paper presents the potential of Fused Deposition Modelling (FDM) system, available at IRIS, in building prototypes of scaled microchannels for experimental study and verification of fluid flow in microfluidic devices. The scope and application of FDM system as a powerful and flexible rapid prototyping device is described. Microchannels of different geometries are produced in ABS material on the FDM3000 rapid prototyping system and a methodology is presented for experimental study of the mixing of fluids in microchannels in conjunction with the theoretical analysis using FlumeCAD system.

  2. Modelling hydrologic impacts of light absorbing aerosol deposition on snow at the catchment scale

    Science.gov (United States)

    Matt, Felix N.; Burkhart, John F.; Pietikäinen, Joni-Pekka

    2018-01-01

    Light absorbing impurities in snow and ice (LAISI) originating from atmospheric deposition enhance snowmelt by increasing the absorption of shortwave radiation. The consequences are a shortening of the snow duration due to increased snowmelt and, at the catchment scale, a temporal shift in the discharge generation during the spring melt season. In this study, we present a newly developed snow algorithm for application in hydrological models that allows for an additional class of input variable: the deposition mass flux of various species of light absorbing aerosols. To show the sensitivity of different model parameters, we first use the model as a 1-D point model forced with representative synthetic data and investigate the impact of parameters and variables specific to the algorithm determining the effect of LAISI. We then demonstrate the significance of the radiative forcing by simulating the effect of black carbon (BC) deposited on snow of a remote southern Norwegian catchment over a 6-year period, from September 2006 to August 2012. Our simulations suggest a significant impact of BC in snow on the hydrological cycle. Results show an average increase in discharge of 2.5, 9.9, and 21.4 %, depending on the applied model scenario, over a 2-month period during the spring melt season compared to simulations where radiative forcing from LAISI is not considered. The increase in discharge is followed by a decrease in discharge due to a faster decrease in the catchment's snow-covered fraction and a trend towards earlier melt in the scenarios where radiative forcing from LAISI is applied. Using a reasonable estimate of critical model parameters, the model simulates realistic BC mixing ratios in surface snow with a strong annual cycle, showing increasing surface BC mixing ratios during spring melt as a consequence of melt amplification. However, we further identify large uncertainties in the representation of the surface BC mixing ratio during snowmelt and the subsequent

  3. Modelling loans and deposits during electoral years i n Romania

    Directory of Open Access Journals (Sweden)

    Nicolae - Marius JULA

    2015-06-01

    Full Text Available This paper analyzes the effect of electoral years on loans and deposits for population in Romania. Using monthly data regarding the total loans and deposits, we identify the significance of the electoral timing on population´s behavior regarding financial decisions. We estimate that there are small changes in population´s affinity for increase in the indebtedness or for savings. We use dummy variables for electoral periods, and when these are econometrically significant there is an evidence of the influence of the electoral timings in population´s financial decisions.

  4. Comparative study on Pulsed Laser Deposition and Matrix Assisted Pulsed Laser Evaporation of urease thin films

    International Nuclear Information System (INIS)

    Smausz, Tomi; Megyeri, Gabor; Kekesi, Renata; Vass, Csaba; Gyoergy, Eniko; Sima, Felix; Mihailescu, Ion N.; Hopp, Bela

    2009-01-01

    Urease thin films were produced by Matrix Assisted Pulsed Laser Evaporation (MAPLE) and Pulsed Laser Deposition from two types of targets: frozen water solutions of urease with different concentrations (1-10% m/v) and pure urease pellets. The fluence of the ablating KrF excimer laser was varied between 300 and 2200 mJ/cm 2 . Fourier transform infrared spectra of the deposited films showed no difference as compared to the original urease. Morphologic studies proved that the films consist of a smooth 'base' layer with embedded micrometer-sized droplets. Absorption-coefficient measurements contradicted the traditional 'absorptive matrix' model for MAPLE deposition. The laser energy was absorbed by urease clusters leading to a local heating-up and evaporation of the frozen matrix from the uppermost layer accompanied by the release of dissolved urease molecules. Significant enzymatic activity of urease was preserved only during matrix assisted transfer.

  5. Land Use Specific Ammonia Deposition Velocities: a Review of Recent Studies (2004-2013).

    Science.gov (United States)

    Schrader, Frederik; Brümmer, Christian

    2014-01-01

    Land use specific deposition velocities of atmospheric trace gases and aerosols-particularly of reactive nitrogen compounds-are a fundamental input variable for a variety of deposition models. Although the concept is known to have shortcomings-especially with regard to bi-directional exchange-the often limited availability of concentration data and meteorological input variables make it a valuable simplification for regional modeling of deposition fluxes. In order to meet the demand for an up-to-date overview of recent publications on measurements and modeling studies, we compiled a database of ammonia (NH 3 ) deposition velocities published from 2004 to 2013. Observations from a total of 42 individual studies were averaged using an objective weighing scheme and classified into seven land use categories. Weighted average and median deposition velocities are 2.2 and 2.1 cm s -1 for coniferous forests, 1.5 and 1.2 cm s -1 for mixed forests, 1.1 and 0.9 cm s -1 for deciduous forests, 0.9 and 0.7 cm s -1 for semi-natural sites, 0.7 and 0.8 cm s -1 for urban sites, 0.7 and 0.6 cm s -1 for water surfaces, and 1.0 and 0.4 cm s -1 for agricultural sites, respectively. Thus, values presented in this compilation were considerably lower than those found in former studies (e.g., VDI 2006). Reasons for the mismatch were likely due to different land use classification, different averaging methods, choices of measurement locations, and improvements in measurement and in modeling techniques. Both data and code used for processing are made available as supplementary material to this article.

  6. A deposit model for magmatic iron-titanium-oxide deposits related to Proterozoic massif anorthosite plutonic suites

    Science.gov (United States)

    Woodruff, Laurel G.; Nicholson, Suzanne W.; Fey, David L.

    2013-01-01

    This descriptive model for magmatic iron-titanium-oxide (Fe-Ti-oxide) deposits hosted by Proterozoic age massif-type anorthosite and related rock types presents their geological, mineralogical, geochemical, and geoenvironmental attributes. Although these Proterozoic rocks are found worldwide, the majority of known deposits are found within exposed rocks of the Grenville Province, stretching from southwestern United States through eastern Canada; its extension into Norway is termed the Rogaland Anorthosite Province. This type of Fe-Ti-oxide deposit dominated by ilmenite rarely contains more than 300 million tons of ore, with between 10- to 45-percent titanium dioxide (TiO2), 32- to 45-percent iron oxide (FeO), and less than 0.2-percent vanadium (V). The origin of these typically discordant ore deposits remains as enigmatic as the magmatic evolution of their host rocks. The deposits clearly have a magmatic origin, hosted by an age-constrained unique suite of rocks that likely are the consequence of a particular combination of tectonic circumstances, rather than any a priori temporal control. Principal ore minerals are ilmenite and hemo-ilmenite (ilmenite with extensive hematite exsolution lamellae); occurrences of titanomagnetite, magnetite, and apatite that are related to this deposit type are currently of less economic importance. Ore-mineral paragenesis is somewhat obscured by complicated solid solution and oxidation behavior within the Fe-Ti-oxide system. Anorthosite suites hosting these deposits require an extensive history of voluminous plagioclase crystallization to develop plagioclase-melt diapirs with entrained Fe-Ti-rich melt rising from the base of the lithosphere to mid- and upper-crustal levels. Timing and style of oxide mineralization are related to magmatic and dynamic evolution of these diapiric systems and to development and movement of oxide cumulates and related melts. Active mines have developed large open pits with extensive waste-rock piles, but

  7. A Mathematical Model for Non-monotonic Deposition Profiles in Deep Bed Filtration Systems

    DEFF Research Database (Denmark)

    Yuan, Hao; Shapiro, Alexander

    2011-01-01

    . The numerical modeling results highly agree with the experimental observations, which proves the ability of the model to catch a non-monotonic deposition profile in practice. An additional equation describing a mobile population behaving differently from the injected population seems to be a sufficient...... by advection and diffusion/dispersion. The proposed model is able to produce a nonmonotonic deposition profile. A set of methods for estimating the modeling parameters is provided in the case of minimal particle release. The estimation can be easily performed with available experimental information...... condition for producing non-monotonic deposition profiles. The described physics by the additional equation may be different in different experimental settings....

  8. 3D modeling of surface quarries and deposits of mined materials and the monitoring of slopes

    Directory of Open Access Journals (Sweden)

    Ivan Maňas

    2007-06-01

    Full Text Available The application of computer technology by simulating opencast mining and deposits of raw materials. The mathematic principles of three-dimensional probabilistic models of raw materials deposits and a familiarization with the user interface software GEOLOGICKY MODEL. The principles of the simulation of opencast mines, generation intersections with models of raw materials deposits, computation of mining materials with the quality scaling,and the design of advanced mining with the software BANSKY MODEL.The monitoring the potential of dynamic movements’ of unstable slopes with the automatic total station and a following interpretation in general time intervals by means of the software MONITORING.

  9. Acidic deposition: State of science and technology. Report 5. Evaluation of regional acidic deposition models (Part 1) and selected applications of RADM (Part 2). Final report

    International Nuclear Information System (INIS)

    Dennis, R.L.; Barchet, W.R.; Clark, T.L.; Seilkop, S.K.; Roth, P.M.

    1990-09-01

    The State-of-Science/Technology report describes the scientific community's current knowledge regarding the evaluation of regional acidic deposition models. The report summarizes this knowledge by describing the process, as well as the history, of evaluating acidic deposition models and by providing the results obtained from the recent evaluations of such models. The concepts of model evaluation, in general, are discussed in early sections of the report, but particular emphasis is placed on Eulerian-style evaluations. The two Eulerian models covered are the Regional Acid Deposition Model (RADM), which was developed for the United States, and the Acid Deposition and Oxidant Model (ADOM), developed for Canada. The results of evaluating several versions of RADM and ADOM have provided model evaluators with the most current assessment of how reliably these models can address several key issues posed by the National Acid Precipitation Assessment Program (NAPAP). That is, how well can the models predict the change in regional acidic deposition that would result from changes in precursor emissions; the influence of sources in one region on acidic deposition in other sensitive receptor regions; the levels of acidic deposition at certain sensitive receptor regions; and the acidic deposition due to emissions transported across geographical/political boundaries, including the United States-Canadian border

  10. NRPB volunteer study: deposition and clearance of inhaled particles

    International Nuclear Information System (INIS)

    Etherington, G.; Smith, J.

    1996-01-01

    At the Board Meeting of the National Radiological Protection Board held on 15 February 1996, approval was given for an experimental study of the deposition and clearance of inhaled particles in the human nasal passage. This is the latest in a series of volunteer biokinetic studies that have been conducted at NRPB since its formation. This article explains the purpose of the study, how ethical approval was obtained, how the study will be performed, what volunteers will be asked to do, and what doses they will receive. Doses will of course be carefully controlled, and will be well below the annual limits set for such experiments. The success of the study is of course crucially dependent on recruitment of a sufficient number of volunteers. The aim of this article is to provide information to anyone who might be interested in volunteering. (UK)

  11. Modeling Dry Deposition of Aerosol Particles on Rough Surfaces

    Czech Academy of Sciences Publication Activity Database

    Hussein, T.; Smolík, Jiří; Kerminen, V.-M.; Kulmala, M.

    2012-01-01

    Roč. 46, č. 1 (2012), s. 44-59 ISSN 0278-6826 Institutional research plan: CEZ:AV0Z40720504 Keywords : aerosol particles * dry deposition * transport Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.780, year: 2012

  12. 3D Numerical Modelling of Transport, Deposition and Resuspension of Highway Deposited Sediments in Wet Detention Ponds

    DEFF Research Database (Denmark)

    Bentzen, Thomas Ruby

    2009-01-01

    concrete channel with width of 0.8 m and a water depth of approximately 0.8 m and in circular flume experiments in order to reproduce near-bed specific processes such as resuspension and consolidation. With good agreement with measurements, modelling of hydrodynamics, transport of dissolved pollutants...... and particles in wet detention ponds is possible with application of a three dimensional RANS model and the advection/dispersion equation taken physical phenomena like wind, waves, deposition, erosion and consolidation of the bottom sediment into account....

  13. The use of sediment deposition maps as auxiliary data for hydraulic model calibration

    Science.gov (United States)

    Mukolwe, Micah; Di Baldassarre, Giuliano; Solomatine, Dimitri

    2013-04-01

    One aspect of the French disaster mitigation setup is the statutory Risk Prevention Plans (PPR, Plans de Prévention des Risques); i.e. spatial identification of potential disasters and mitigation measures. The maps are categorised into three zones depicting increasing disaster severity and potential mitigation measures (RTM, 1999). Taking the example of the city of Barcelonnette, in South France (French Alps), floods have been the most frequent occurring natural hazard (Flageollet et al., 1996). Consequently, a case is put forward for the need for accurate flood extent delineation to support the decision making process. For this study, the Barcelonnette case study was considered, whereby the last devastating flooding was in June 1957 (Weber, 1994). Contrary to the recent advances in the proliferation of data to support flood inundation studies (Bates, 2012; Bates, 2004; Di Baldassarre and Uhlenbrook, 2012; Schumann et al., 2009), constraints are faced when analysing flood inundation events that occurred before the 1970's. In absence of frequent flooding, the analysis of historical flood extents may play an important role in shaping the awareness of local stakeholders and support land-use and urban planning. This study is part of a probabilistic flood mapping (e.g. Di Baldassarre et al., 2010, Horrit, 2006) of the valley carried out in a Monte-Carlo framework, while taking into account the peak flow and the parametric uncertainty. The simulations were carried out using the sub-grid channel model extension of the LISFLOOD-FP hydraulic model (Bates et al, 2010; Neal et al., 2012). Sediment deposition maps (Lecarpentier, 1963) were used to analyse the model performance, additionally the graduation of the sediment deposition sizes showed the flood propagation and was used to analyse the model runs. However, there still remains the challenge of quantifying the uncertainty in the sediment deposition map and the actual flood extent.

  14. A study of naturally occurring, radionuclide bearing deposits at Portland Creek, Newfoundland

    International Nuclear Information System (INIS)

    1985-01-01

    A small uraniferous peat deposit located near Portland Creek, Newfoundland was investigated as part of the National Uranium Tailings Program (NUTP). The purpose of the investigation was to provide data on naturally occurring uranium series radionuclides at a surface location that could be used to compare with the predictions of mathematical models. The investigation was carried out between August 18 and 30, 1984 by CBCL Limited with the assistance of Golder Associates, SENES Consultants Limited, Environmental Design Group and Monenco Analytical Laboratories. The investigation involved the determination of the geological and hydrogeological conditions of the deposit site and collection of soil, water and biological samples. The samples were analyzed for major element chemistry, uranium and its various decay series radionuclides including radium-226 and the ratio of uranium-234 to uranium-238. The uranium mineralization was found to be associated with a peat deposit that has accumulated in post-glacial time. The deposit is situated within a groundwater discharge zone at the toe of a granitic talus pile that extends downward from the Long Range Mountains. The concentration of uranium within the peat deposit was found to vary from 100 to 28000 ppm, however, the activities of the uranium decay series radionuclides were comparatively very low. Radium-226 activities were found to vary from 0.5 Bq/g to 15.0 Bq/g. Little influence from the deposit was noted in the surrounding water bodies, fish samples and vegetation. Based on the results of the study the uranium mineralization within the peat is considered to be the result of precipitation or adsorption from groundwater that had previously leached uranium from the granitic talus which forms the groundwater recharge zone. The major geochemical mechanism for deposition is considered to be associated with the strong reducing conditions encountered within the peat. Being a recent deposit (i.e. less than 10,000-15,000 years old

  15. Integration of rock physical signatures with depositional environments: A case study from East Coast of India

    Science.gov (United States)

    Mondal, Samit; Yadav, Ashok; Chatterjee, Rima

    2018-01-01

    Rock physical crossplots from different geological setup along eastern continental margin of India (ECMI) represent diversified signatures. To characterize the reservoirs in rock physics domain (velocity/modulus versus porosity) and then connecting the interpretation with geological model has been the objectives of the present study. Petrophysical logs (total porosity and volume of shale) from five wells located at sedimentary basins of ECMI have been analyzed to quantify the types of shale such as: laminated, dispersed and structural in reservoir. Presence of various shale types belonging to different depositional environments is coupled to define distinct rock physical crossplot trends for different geological setup. Wells from three different basins in East Coast of India have been used to capture diversity in depositional environments. Contact model theory has been applied to the crossplot to examine the change in rock velocity with change in reservoir properties like porosity and volume of shale. The depositional and diagenetic trends have been shown in the crossplot to showcase the prime controlling factor which reduces the reservoir porosity. Apart from that, the effect of geological factors like effective stress, sorting, packing, grain size uniformity on reservoir properties have also been focused. The rock physical signatures for distinct depositional environments, effect of crucial geological factors on crossplot trends coupled with established sedimentological models in drilled area are investigated to reduce the uncertainties in reservoir characterization for undrilled potentials.

  16. Reactive ballistic deposition of nanostructured model materials for electrochemical energy conversion and storage.

    Science.gov (United States)

    Flaherty, David W; Hahn, Nathan T; May, R Alan; Berglund, Sean P; Lin, Yong-Mao; Stevenson, Keith J; Dohnalek, Zdenek; Kay, Bruce D; Mullins, C Buddie

    2012-03-20

    Porous, high surface area materials have critical roles in applications including catalysis, photochemistry, and energy storage. In these fields, researchers have demonstrated that the nanometer-scale structure modifies mechanical, optical, and electrical properties of the material, greatly influencing its behavior and performance. Such complex chemical systems can involve several distinct processes occurring in series or parallel. Understanding the influence of size and structure on the properties of these materials requires techniques for producing clean, simple model systems. In the fields of photoelectrochemistry and lithium storage, for example, researchers need to evaluate the effects of changing the electrode structure of a single material or producing electrodes of many different candidate materials while maintaining a distinctly favorable morphology. In this Account, we introduce our studies of the formation and characterization of high surface area, porous thin films synthesized by a process called reactive ballistic deposition (RBD). RBD is a simple method that provides control of the morphology, porosity, and surface area of thin films by manipulating the angle at which a metal-vapor flux impinges on the substrate during deposition. This approach is largely independent of the identity of the deposited material and relies upon limited surface diffusion during synthesis, which enables the formation of kinetically trapped structures. Here, we review our results for the deposition of films from a number of semiconductive materials that are important for applications such as photoelectrochemical water oxidation and lithium ion storage. The use of RBD has enabled us to systematically control individual aspects of both the structure and composition of thin film electrodes in order to probe the effects of each on the performance of the material. We have evaluated the performance of several materials for potential use in these applications and have identified

  17. Studies of tritiated co-deposited layers in TFTR

    Energy Technology Data Exchange (ETDEWEB)

    SKINNER,C.H.; GENTILE,C.A.; ASCIONE,G.; CAUSEY,R.A.; HAYASKI,T.; HOGAN,J.; NISHI,M.; SHU,W.M.; WAMPLER,WILLIAM R.; YOUNG,K.M.

    2000-05-30

    Plasma facing components in TFTR contain an important record of plasma wall interactions in reactor grade DT plasmas. Tiles, flakes, wall coupons and dust samples have been retrieved from the TFTR vessel for analysis. Selected samples have been baked to release tritium and assay the tritium content. The in-vessel tritium inventory is estimated to be 0.5 g and is consistent with the in-vessel tritium inventory derived from the difference between tritium fueling and tritium exhaust. Relatively high concentrations of tritium were found at the top and bottom of the bumper limiter, as predicted by earlier BBQ modeling. The distribution of tritium on the limiter and vessel wall showed complex patterns of co-deposition.

  18. Studies of tritiated co-deposited layers in TFTR

    Energy Technology Data Exchange (ETDEWEB)

    Skinner, C.H. E-mail: cskinner@pppl.gov; Gentile, C.A.; Ascione, G.; Carpe, A.; Causey, R.A.; Hayashi, T.; Hogan, J.; Langish, S.; Nishi, M.; Shu, W.M.; Wampler, W.R.; Young, K.M

    2001-03-01

    Plasma facing components in TFTR contain an important record of plasma wall interactions in reactor grade DT plasmas. Tiles, flakes, wall coupons, a stainless steel shutter and dust samples have been retrieved from the TFTR vessel for analysis. Selected samples have been baked to release tritium and assay the tritium content. The in-vessel tritium inventory is estimated to be 0.56 g and is consistent with the in-vessel tritium inventory derived from the difference between tritium fueling and tritium exhaust. The distribution of tritium on the limiter and vessel wall showed complex patterns of co-deposition. Relatively high concentrations of tritium were found at the top and bottom of the bumper limiter, as predicted by earlier BBQ modeling.

  19. Studies of tritiated co-deposited Layers in TFTR

    Energy Technology Data Exchange (ETDEWEB)

    Skinner, C.H.; Gentile, C.A.; Ascione, G.; Carpe, A.; Causey, R.A.; Hayashi, T.; Hogan, J.; Langish, S.W.; Nishi, M.F.; Shu, W.M.; Wampler, W.R.; Young, K.M.

    2000-05-22

    Plasma facing components in TFTR contain an important record of plasma wall interactions in reactor grade DT plasmas. Tiles, flakes, wall coupons, a stainless steel shutter and dust samples have been retrieved from the TFTR vessel for analysis. Selected samples have been baked to release tritium and assay the tritium content. The in-vessel tritium inventory is estimated to be 0.56 g and is consistent with the in-vessel tritium inventory derived from the difference between tritium fueling and tritium exhaust. The distribution of tritium on the limiter and vessel wall showed complex patterns of co-deposition. Relatively high concentrations of tritium were found at the top and bottom of the bumper limiter, as predicted by earlier BBQ modeling.

  20. Studies of tritiated co-deposited layers in TFTR

    Energy Technology Data Exchange (ETDEWEB)

    C.H. Skinner; C.A. Gentile; G. Ascione; A. Carpe; R.A. Causey; T. Hayashi; J. Hogan; S. Langish; M. Nishi; W.M. Shu; W.R. Wampler; K. M. Young

    2000-06-28

    Plasma facing components in TFTR contain an important record of plasma wall interactions in reactor grade DT plasmas. Tiles, flakes, wall coupons, a stainless steel shutter and dust samples have been retrieved from the TFTR vessel for analysis. Selected samples have been baked to release tritium and assay the tritium content. The in-vessel tritium inventory is estimated to be 0.56 g and is consistent with the in-vessel tritium inventory derived from the difference between tritium fueling and tritium exhaust. The distribution of tritium on the limiter and vessel wall showed complex patterns of co-deposition. Relatively high concentrations of tritium were found at the top and bottom of the bumper limiter, as predicted by earlier BBQ modeling.

  1. Studies of tritiated co-deposited layers in TFTR

    International Nuclear Information System (INIS)

    Skinner, C.H.; Gentile, C.A.; Ascione, G.; Carpe, A.; Causey, R.A.; Hayashi, T.; Hogan, J.; Langish, S.; Nishi, M.; Shu, W.M.; Wampler, W.R.; Young, K.M.

    2000-01-01

    Plasma facing components in TFTR contain an important record of plasma wall interactions in reactor grade DT plasmas. Tiles, flakes, wall coupons, a stainless steel shutter and dust samples have been retrieved from the TFTR vessel for analysis. Selected samples have been baked to release tritium and assay the tritium content. The in-vessel tritium inventory is estimated to be 0.56 g and is consistent with the in-vessel tritium inventory derived from the difference between tritium fueling and tritium exhaust. The distribution of tritium on the limiter and vessel wall showed complex patterns of co-deposition. Relatively high concentrations of tritium were found at the top and bottom of the bumper limiter, as predicted by earlier BBQ modeling

  2. Studies of tritiated co-deposited layers in TFTR

    International Nuclear Information System (INIS)

    Skinner, C.H.; Gentile, C.A.; Ascione, G.; Causey, R.A.; Hayaski, T.; Hogan, J.; Nishi, M.; Shu, W.M.; Wampler, William R.; Young, K.M.

    2000-01-01

    Plasma facing components in TFTR contain an important record of plasma wall interactions in reactor grade DT plasmas. Tiles, flakes, wall coupons and dust samples have been retrieved from the TFTR vessel for analysis. Selected samples have been baked to release tritium and assay the tritium content. The in-vessel tritium inventory is estimated to be 0.5 g and is consistent with the in-vessel tritium inventory derived from the difference between tritium fueling and tritium exhaust. Relatively high concentrations of tritium were found at the top and bottom of the bumper limiter, as predicted by earlier BBQ modeling. The distribution of tritium on the limiter and vessel wall showed complex patterns of co-deposition

  3. Studies of tritiated co-deposited Layers in TFTR

    International Nuclear Information System (INIS)

    Skinner, C.H.; Gentile, C.A.; Ascione, G.; Carpe, A.; Causey, R.A.; Hayashi, T.; Hogan, J.; Langish, S.W.; Nishi, M.F.; Shu, W.M.; Wampler, W.R.; Young, K.M.

    2000-01-01

    Plasma facing components in TFTR contain an important record of plasma wall interactions in reactor grade DT plasmas. Tiles, flakes, wall coupons, a stainless steel shutter and dust samples have been retrieved from the TFTR vessel for analysis. Selected samples have been baked to release tritium and assay the tritium content. The in-vessel tritium inventory is estimated to be 0.56 g and is consistent with the in-vessel tritium inventory derived from the difference between tritium fueling and tritium exhaust. The distribution of tritium on the limiter and vessel wall showed complex patterns of co-deposition. Relatively high concentrations of tritium were found at the top and bottom of the bumper limiter, as predicted by earlier BBQ modeling

  4. Multi-elements atmospheric deposition study in Albania.

    Science.gov (United States)

    Qarri, Flora; Lazo, Pranvera; Stafilov, Trajce; Frontasyeva, Marina; Harmens, Harry; Bekteshi, Lirim; Baceva, Katerina; Goryainova, Zoya

    2014-02-01

    For the first time, the moss biomonitoring technique and inductively coupled plasma-atomic emission spectrometric (ICP-AES) analytical technique were applied to study multi-element atmospheric deposition in Albania. Moss samples (Hypnum cupressiforme) were collected during the summer of 2011 and September-October 2010 from 62 sites, evenly distributed over the country. Sampling was performed in accordance with the LRTAP Convention-ICP Vegetation protocol and sampling strategy of the European Programme on Biomonitoring of Heavy Metal Atmospheric Deposition. ICP-AES analysis made it possible to determine concentrations of 19 elements including key toxic metals such as Pb, Cd, As, and Cu. Cluster and factor analysis with varimax rotation was applied to distinguish elements mainly of anthropogenic origin from those predominantly originating from natural sources. Geographical distribution maps of the elements over the sampled territory were constructed using GIS technology. The median values of the elements in moss samples of Albania were high for Al, Cr, Ni, Fe, and V and low for Cd, Cu, and Zn compared to other European countries, but generally were of a similar level as some of the neighboring countries such as Bulgaria, Croatia, Kosovo, Macedonia, and Romania. This study was conducted in the framework of ICP Vegetation in order to provide a reliable assessment of air quality throughout Albania and to produce information needed for better identification of contamination sources and improving the potential for assessing environmental and health risks in Albania, associated with toxic metals.

  5. Influence of the Flexible Liposomes on the Skin Deposition of a Hydrophilic Model Drug, Carboxyfluorescein: Dependency on Their Composition

    Directory of Open Access Journals (Sweden)

    Mohamed Badran

    2012-01-01

    Full Text Available This study focuses on the effect of different flexible liposomes containing sodium cholate, Tween 80, or cineol on skin deposition of carboxyfluorescein (CF. Size distribution, morphology, zeta potential, and stability of the prepared vesicles were evaluated. The influence of these systems on the skin deposition of CF utilizing rat skin as membrane model was investigated. Results showed that all of the investigated liposomes had almost spherical shapes with low polydispersity (PDI < 0.3 and particles size range from 83 to 175 nm. All liposomal formulations exhibited negative zeta potential, good drug entrapment efficiency, and stability. In vitro skin deposition data showed that flexible liposomes gave significant deposition of CF on the skin compared to conventional liposomes and drug solutions. This study revealed that flexible liposomes, containing cineole, were able to deliver higher amount of CF suggesting that the hydrophilic drugs delivery to the skin was strictly correlated to the vesicle composition.

  6. Dependence of ECH deposition profile on the modeling of incident wave energy

    International Nuclear Information System (INIS)

    Kritz, A.H.; Hsuan, H.; Matsuda, K.

    1986-06-01

    The ray tracing code, TORAY, is used to investigate the importance of modeling assumptions utilized in describing Electron Cyclotron Heating (ECH). In particular, we examine the dependence of the ECH deposition profile on the antenna pattern. We demonstrate that different assumptions for representing the incident wave energy by a finite number of rays lead to significantly different results for the energy deposition profile

  7. Concurrent Modeling of Hydrodynamics and Interaction Forces Improves Particle Deposition Predictions.

    Science.gov (United States)

    Jin, Chao; Ren, Carolyn L; Emelko, Monica B

    2016-04-19

    It is widely believed that media surface roughness enhances particle deposition-numerous, but inconsistent, examples of this effect have been reported. Here, a new mathematical framework describing the effects of hydrodynamics and interaction forces on particle deposition on rough spherical collectors in absence of an energy barrier was developed and validated. In addition to quantifying DLVO force, the model includes improved descriptions of flow field profiles and hydrodynamic retardation functions. This work demonstrates that hydrodynamic effects can significantly alter particle deposition relative to expectations when only the DLVO force is considered. Moreover, the combined effects of hydrodynamics and interaction forces on particle deposition on rough, spherical media are not additive, but synergistic. Notably, the developed model's particle deposition predictions are in closer agreement with experimental observations than those from current models, demonstrating the importance of inclusion of roughness impacts in particle deposition description/simulation. Consideration of hydrodynamic contributions to particle deposition may help to explain discrepancies between model-based expectations and experimental outcomes and improve descriptions of particle deposition during physicochemical filtration in systems with nonsmooth collector surfaces.

  8. New Functions to Model Measured Deposition and Resuspension Rates of Particles

    DEFF Research Database (Denmark)

    Lengweiler, P.; Moser, A.; Nielsen, Peter V.

    New functions to model deposition and resuspension rates based on experimental data are introduced. Deposition and resuspension are presented in dependence on the surface orientation as well as on the turbulent kinetic energy of the air. Moreover, the development of the dust building up on the su...

  9. Multi-model Mean Nitrogen and Sulfur Deposition from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP): Evaluation Historical and Projected Changes

    Science.gov (United States)

    Lamarque, J.-F.; Dentener, F.; McConnell, J.; Ro, C.-U.; Shaw, M.; Vet, R.; Bergmann, D.; Cameron-Smith, P.; Doherty, R.; Faluvegi, G.; hide

    2013-01-01

    We present multi-model global datasets of nitrogen and sulfate deposition covering time periods from 1850 to 2100, calculated within the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP). The computed deposition fluxes are compared to surface wet deposition and ice-core measurements. We use a new dataset of wet deposition for 2000-2002 based on critical assessment of the quality of existing regional network data. We show that for present-day (year 2000 ACCMIP time-slice), the ACCMIP results perform similarly to previously published multi-model assessments. For this time slice, we find a multi-model mean deposition of 50 Tg(N) yr1 from nitrogen oxide emissions, 60 Tg(N) yr1 from ammonia emissions, and 83 Tg(S) yr1 from sulfur emissions. The analysis of changes between 1980 and 2000 indicates significant differences between model and measurements over the United States but less so over Europe. This difference points towards misrepresentation of 1980 NH3 emissions over North America. Based on ice-core records, the 1850 deposition fluxes agree well with Greenland ice cores but the change between 1850 and 2000 seems to be overestimated in the Northern Hemisphere for both nitrogen and sulfur species. Using the Representative Concentration Pathways to define the projected climate and atmospheric chemistry related emissions and concentrations, we find large regional nitrogen deposition increases in 2100 in Latin America, Africa and parts of Asia under some of the scenarios considered. Increases in South Asia are especially large, and are seen in all scenarios, with 2100 values more than double 2000 in some scenarios and reaching 1300 mg(N) m2 yr1 averaged over regional to continental scale regions in RCP 2.6 and 8.5, 3050 larger than the values in any region currently (2000). The new ACCMIP deposition dataset provides novel, consistent and evaluated global gridded deposition fields for use in a wide range of climate and ecological studies.

  10. Three-dimensional sedimentary architecture of Quaternary deposits; a case study of environmental sedimentology (Bam, Iran)

    Science.gov (United States)

    Rezaei, K.; Guest, B.; Friedrich, A.; Fayazi, F.; Nakhaei, M.; Bakhtiari, H.; Nouri, L.

    2009-04-01

    Detailed 3-D analysis of the sedimentary structure and stratigraphy of these deposits allows for an accurate understand of sedimentary model of basin. This paper presents a case study in Bam (SE Iran) reconstructing the 3-D distribution of fluvial sediments based on a high resolution, process-orientated sedimentary facies classification and lithostratigraphy. We investigated the mean grain size with vertical and horizontal change of it, clay mineralogy, sediment texture, sedimentary structures, petrology and petrography and determination of paleo-environments and finally, we prepared two cross sections in S-N and W-E directions and a 3D block diagram for the situation of changes in subsurface sediments and compare them with the destruction rate map of earthquake in Bam city. Quaternary alluvial sediments are characterized by lithofacies deposited by braided river channels, debris flows and hyperconcentrated flows. The channel flow deposits constitute relatively well sorted, well imbricated and clast-supported gravels with coarse to medium sand matrix. Mostly poorly sorted, weakly imbricated to disorganized matrix supported pebble to boulder gravels with silty sand represent debris flow deposits. Hyperconcentrated flow deposits consist of clast-supported, poorly developed sorted polymodal gravel facies with poorly developed imbricated fabric, and generally occupy the lower parts of the terrace and fan sequences. The alternation from hyperconcentrated flow to channel flow deposits is predominant in the sequence, and is possibly the response to different climate modes. The high discharge and supply of sediments as well as the dispersal and deposition of these materials in the trunk stream is attributed to climatic perturbations during the Quaternary. These models allow quantifying the thickness and volume distribution of sandy gravel and clay deposits. We correlate these sedimentary units on the basis of lithofacies similarities, stratigraphic position. These

  11. Heavy metal atmospheric deposition study in the South Ural Mountains

    International Nuclear Information System (INIS)

    Frontasyeva, M.V.; Smirnov, L.I.; Lyapunov, S.M.

    2004-01-01

    Samples of the mosses Hylocomium splendens and Pleurozium schreberi, collected in the summer of 1998, were used to study the atmospheric deposition of heavy metals and other toxic elements in the Chelyabinsk Region situated in the South Urals, one of the most heavily polluted industrial areas of the Russian Federation. Samples of natural soils were collected simultaneously with moss at the same 30 sites in order to investigate surface accumulation of heavy metals and to examine the correlation of elements in moss and soil samples in order to separate contributions from atmospheric deposition and from soil minerals. A total of 38 elements (Na, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, As, Se, Rb, Sr, Zr, Mo, Sb, Cs, Ba, La, Ce, Nd, Sm, Eu, Gd, Tb, Dy, Yb, Hf, Ta, W, Au, Th, U) in soil and 33 elements Na, Mg, Al, Cl, K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni, Zn, As, Se, Br, Rb, Ag, Sb, Cs, Ba, La, Ce, Sm, Tb, Yb, Hf, Ta, W, Au, Th, U) were determined by epithermal neutron activation analysis. The elements Cu, Cd and Pb (in moss samples only) were obtained by atomic absorption spectrometry. VARIMAX rotated principal component analysis was used to identify and characterize different pollution sources and to point out the most polluted areas. (author)

  12. Experimental and numerical study of deposit formation in secondary side SG TSP by electrokinetic approach

    International Nuclear Information System (INIS)

    Guillodo, Michael; Foucault, Marc; Ryckelynck, Natacha; Chahma, Farah; Guingo, Mathieu; Mansour, Carine; Alos-Ramos, Olga; Corredera, Geraldine

    2012-09-01

    Corrosion products deposit formation observed in PWR steam generators (SGs) - related to SG free span fouling and SG clogging - is now reported since several years. SG clogging is a localized phenomenon observed between the leading edge of the Tube Support Plate (TSP) and SG tubing materials. Based on visual inspections, it was found that the gaps between SG tubing material and TSP at the lower part of the broached holes were getting progressively blocked. Therefore, for safe operation, most affected PWRs had to be operated at reduced power. TSP blockage was mainly observed for low-pH water chemistry conditioning, which directly depends on the operating water chemistry. The TSP blockage mechanism is complex due to the localized conditions in which flow pattern change, chemistry and electrochemical conditions are not well understood. Electrokinetic considerations could be pointed out to explain the coupling of chemistry, materials and thermohydraulic (T/H) conditions. In this frame AREVA and EDF have launched a long-term R and D program in order to understand the mechanisms driving the formation of SG clogging. This study based on parametric laboratory tests aims to assess the role of secondary water chemistry, material and T/H conditions on deposit formation. The experimental approach focused on electrokinetic measurements of metallic substrates and on the assessment of oxidation properties of materials in secondary side chemistry. An overall analysis of recent results is presented to address SG deposit formation in secondary water chemistry for various conditioning amines - morpholine, ethanolamine and dimethylamine. To complete the study, the experimental results have been correlated to CFD simulations of particle deposition, by means of stochastic Lagrangian models. These calculations have in particular reproduced correctly the location of the most important particle deposit (the leading edge of the test tube), and have stressed the influence of the

  13. Studies on structure and organization of calcium carbonate deposits in algae

    Digital Repository Service at National Institute of Oceanography (India)

    Kerkar, V.; Untawale, A.G.

    The structure and organization of calcium carbonate deposits is studied in species of Halimeda, Udotea, Neomeris (Chlorophyta) and Padina (Phaeophyta). It was found that in Halimeda aragonite deposition takes place outside the cell wall...

  14. DESIGNING THE DEPOSITS MANAGEMENT MODEL IN FUNCTION OF BANKING ACTIVITIES OPTIMIZATION

    Directory of Open Access Journals (Sweden)

    Ticijan Peruško

    2011-02-01

    Full Text Available The purpose of this paper is to improve the banks deposits’ management process that will ultimately result in the collection of deposits at lowest costs. In order to achieve the aforementioned purpose, the authors have derived model using statistical and mathematical methods. Statistical method of double logarithmic regression was applied in order to determine the relations between the costs and amount of funds collected from each deposit product, while in the process of deposit assortment optimization nonlinear programming was applied, as the correlation between costs and the amount of collected funds from the sale of deposits products is nonlinear what is shown in the selected regression model too. In order to present the usefulness and wide possibilities of its use, the deposits management model was employed on the example of one large bank that operates in the Croatian banking market. The model is applicable both to the retail sector and corporate sector deposits. Information derived from the model application help banks management in making appropriate decisions regarding planning and managing the sales of deposits and, along with other existing instruments, complements the database of banks management information system.

  15. 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

  16. Plasma and process characterization of high power magnetron physical vapor deposition with integrated plasma equipment--feature profile model

    International Nuclear Information System (INIS)

    Zhang Da; Stout, Phillip J.; Ventzek, Peter L.G.

    2003-01-01

    High power magnetron physical vapor deposition (HPM-PVD) has recently emerged for metal deposition into deep submicron features in state of the art integrated circuit fabrication. However, the plasma characteristics and process mechanism are not well known. An integrated plasma equipment-feature profile modeling infrastructure has therefore been developed for HPM-PVD deposition, and it has been applied to simulating copper seed deposition with an Ar background gas for damascene metalization. The equipment scale model is based on the hybrid plasma equipment model [M. Grapperhaus et al., J. Appl. Phys. 83, 35 (1998); J. Lu and M. J. Kushner, ibid., 89, 878 (2001)], which couples a three-dimensional Monte Carlo sputtering module within a two-dimensional fluid model. The plasma kinetics of thermalized, athermal, and ionized metals and the contributions of these species in feature deposition are resolved. A Monte Carlo technique is used to derive the angular distribution of athermal metals. Simulations show that in typical HPM-PVD processing, Ar + is the dominant ionized species driving sputtering. Athermal metal neutrals are the dominant deposition precursors due to the operation at high target power and low pressure. The angular distribution of athermals is off axis and more focused than thermal neutrals. The athermal characteristics favor sufficient and uniform deposition on the sidewall of the feature, which is the critical area in small feature filling. In addition, athermals lead to a thick bottom coverage. An appreciable fraction (∼10%) of the metals incident to the wafer are ionized. The ionized metals also contribute to bottom deposition in the absence of sputtering. We have studied the impact of process and equipment parameters on HPM-PVD. Simulations show that target power impacts both plasma ionization and target sputtering. The Ar + ion density increases nearly linearly with target power, different from the behavior of typical ionized PVD processing. The

  17. Deposition of magnetic particles: a computer simulation study

    International Nuclear Information System (INIS)

    Santos, F de los; Tasinkevych, M; Tavares, J M; Teixeira, P I C

    2003-01-01

    We report a Monte Carlo simulation of deposition of magnetic particles on a one-dimensional substrate. Incoming particles interact with those that are already part of the deposit via a dipole-dipole potential. The strength of the dipolar interaction is controlled by an effective temperature T*, the case of pure diffusion-limited deposition being recovered in the limit T* → ∞. Preliminary results suggest that the fractal dimension of the deposits does not change with temperature but that there is a (temperature-dependent) crossover from regimes of temperature-dependent to universal behaviour. Furthermore, it was found that dipoles tend to align with the local direction of growth

  18. Comparative study of tantalum deposition by chemical vapor deposition and electron beam vacuum evaporation

    International Nuclear Information System (INIS)

    Spitz, J.; Chevallier, J.

    1975-01-01

    The coating by tantalum of steel parts has been carried out by the two following methods: chemical vapor deposition by hydrogen reduction of TaCl 5 (temperature=1100 deg C, pressure=200 mmHg, H 2 /TaCl 5 =10); electron beam vacuum evaporation. In this case Ta was firstly condensed by ion plating (P(Ar)=5x10 -3 up to 2x10 -2 mmHg; U(c)=3 to -4kV and J(c)=0.2 to 1mAcm -2 ) in order to ensure a good adhesion between deposit and substrate; then by vacuum condensation (substrate temperature: 300 to 650 deg C) to ensure that the coating is impervious to HCl an H 2 SO 4 acids. The advantages and inconveniences of each method are discussed [fr

  19. Preliminary Investigation of Poly-Ether-Ether-Ketone Based on Fused Deposition Modeling for Medical Applications

    Directory of Open Access Journals (Sweden)

    Feng Zhao

    2018-02-01

    Full Text Available Poly-ether-ether-ketone (PEEK fabricated by fused deposition modeling for medical applications was evaluated in terms of mechanical strength and in vitro cytotoxicity in this study. Orthogonal experiments were firstly designed to investigate the significant factors on tensile strength. Nozzle temperature, platform temperature, and the filament diameter were tightly controlled for improved mechanical strength performance. These sensitive parameters affected the interlayer bonding and solid condition in the samples. Fourier transform infrared (FTIR spectrometry analysis was secondly conducted to compare the functional groups in PEEK granules, filaments, and printed parts. In vitro cytotoxicity test was carried out at last, and no toxic substances were introduced during the printing process.

  20. Comprehensive impedance model of cobalt deposition in sulfate solutions accounting for homogeneous reactions and adsorptive effects

    International Nuclear Information System (INIS)

    Vazquez-Arenas, Jorge; Pritzker, Mark

    2011-01-01

    A comprehensive physicochemical model for cobalt deposition onto a cobalt rotating disk electrode in sulfate-borate (pH 3) solutions is derived and statistically fit to experimental EIS spectra obtained over a range of CoSO 4 concentrations, overpotentials and rotation speeds. The model accounts for H + and water reduction, homogeneous reactions and mass transport within the boundary layer. Based on a thermodynamic analysis, the species CoSO 4(aq) , B(OH) 3(aq) , B 3 O 3 (OH) 4 - , H + and OH - and two homogeneous reactions (B(OH) 3(aq) hydrolysis and water dissociation) are included in the model. Kinetic and transport parameters are estimated by minimizing the sum-of-squares error between the model and experimental measurements using a simplex method. The electrode response is affected most strongly by parameters associated with the first step of Co(II) reduction, reflecting its control of the rate of Co deposition, and is moderately sensitive to the parameters for H + reduction and the Co(II) diffusion coefficient. Water reduction is found not to occur to any significant extent under the conditions studied. These trends are consistent with that obtained by fitting equivalent electrical circuits to the experimental spectra. The simplest circuit that best fits the data consists of two RQ elements (resistor-constant phase element) in parallel or series with the solution resistance.

  1. A study of the deposition process of multilayer coatings on the inner tube surface with the pulsed laser deposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Lozovan, A.A., E-mail: loz-plasma@ya.ru; Alexandrova, S.S.; Mishnev, M.A.; Prishepov, S.V.

    2014-02-15

    Highlights: • Submitted laser bench for coatings, deposited on the inner surfaces of tubes by PLD. • Sprayed multilayered Ti/TiN coatings on the inner surfaces of tubes of small diameter. • We study this of coatings by method RBS and X-ray fluorescence spectroscopy (TXRF). • Shown a significant mixing of the layers thickness of 90 μm. -- Abstract: The multilayer Ti/TiN/Ti coatings (consisting of nano-scale layers) on the inner surface of stainless steel tubes of small diameter were studied. The coatings were deposited by using the pulsed laser deposition (PLD) technique (in the reactive and non-reactive deposition modes). The coatings were analyzed using the X-ray fluorescence analysis with total external reflection (TXRF) and the Rutherford backscattering spectroscopy (RBS). It was found that the deposition of multilayer Ti/TiN/Ti coatings leads to the essential mixing of coating layers due to sputtering of coatings with fast atoms and ions from the laser plume and the evaporation of the coating under the laser radiation reflected from the target surface.

  2. Defect studies of thin ZnO films prepared by pulsed laser deposition

    International Nuclear Information System (INIS)

    Vlček, M; Čížek, J; Procházka, I; Novotný, M; Bulíř, J; Lančok, J; Anwand, W; Brauer, G; Mosnier, J-P

    2014-01-01

    Thin ZnO films were grown by pulsed laser deposition on four different substrates: sapphire (0 0 0 1), MgO (1 0 0), fused silica and nanocrystalline synthetic diamond. Defect studies by slow positron implantation spectroscopy (SPIS) revealed significantly higher concentration of defects in the studied films when compared to a bulk ZnO single crystal. The concentration of defects in the films deposited on single crystal sapphire and MgO substrates is higher than in the films deposited on amorphous fused silica substrate and nanocrystalline synthetic diamond. Furthermore, the effect of deposition temperature on film quality was investigated in ZnO films deposited on synthetic diamond substrates. Defect studies performed by SPIS revealed that the concentration of defects firstly decreases with increasing deposition temperature, but at too high deposition temperatures it increases again. The lowest concentration of defects was found in the film deposited at 450° C.

  3. Modeling chemical vapor deposition of silicon dioxide in microreactors at atmospheric pressure

    NARCIS (Netherlands)

    Konakov, S.A.; Krzhizhanovskaya, V.V.

    2015-01-01

    We developed a multiphysics mathematical model for simulation of silicon dioxide Chemical Vapor Deposition (CVD) from tetraethyl orthosilicate (TEOS) and oxygen mixture in a microreactor at atmospheric pressure. Microfluidics is a promising technology with numerous applications in chemical synthesis

  4. The respiratory tract deposition model proposed by the ICRP Task Group

    International Nuclear Information System (INIS)

    James, A.C.; Briant, J.K.; Stahlhofen, W.; Rudolf, G.; Gehr, P.

    1990-11-01

    The Task Group has developed a new model of the deposition of inhaled aerosols in each anatomical region of the respiratory tract. The model is used to evaluate the fraction of airborne activity that is deposited in respiratory regions having distinct retention characteristics and clearance pathways: the anterior nares, the extrathoracic airways of the naso- and oropharynx and larynx, the bronchi, the bronchioles, and the alveolated airways of the lung. Drawn from experimental data on total and regional deposition in human subjects, the model is based on extrapolation of these data by means of a detailed theoretical model of aerosol transport and deposition within the lung. The Task Group model applies to all practical conditions, and for aerosol particles and vapors from atomic size up to very coarse aerosols with an activity median aerodynamic diameter of 100 μm. The model is designed to predict regional deposition in different subjects, including adults of either sex, children of various ages, and infants, and also to account for anatomical differences among Caucasian and non-Caucasian subjects. The Task Group model represents aerosol inhalability and regional deposition in different subjects by algebraic expressions of aerosol size, breathing rates, standard lung volumes, and scaling factors for airway dimensions. 35 refs., 13 figs., 2 tabs

  5. Numerical modeling of an alloy droplet deposition with non-equilibrium solidification

    Science.gov (United States)

    Ramanuj, Vimal

    Droplet deposition is a process of extensive relevance to the microfabrication industry. Various bonding and film deposition methods utilize single or multiple droplet impingements on a substrate with subsequent splat formation through simultaneous spreading and solidification. Splat morphology and solidification characteristics play vital roles in determining the final outcome. Experimental methods have limited reach in studying such phenomena owing to the extremely small time and length scales involved. Fundamental understanding of the governing principles of fluid flow, heat transfer and phase change provide effective means of studying such processes through computational techniques. The present study aims at numerically modeling and analyzing the phenomenon of splat formation and phase change in an alloy droplet deposition process. Phase change in alloys occurs non-isothermally and its formulation poses mathematical challenges. A highly non-linear flow field in conjunction with multiple interfaces and convection-diffusion governed phase transition are some of the highlighting features involved in the numerical formulation. Moreover, the non-equilibrium solidification behavior in eutectic systems is of prime concern. The peculiar phenomenon requires special treatments in terms of modeling solid phase species diffusion, liquid phase enrichment during solute partitioning and isothermal eutectic transformation. The flow field is solved using a two-step projection algorithm coupled with enhanced interface modeling schemes. The free surface tracking and reconstruction is achieved through two approaches: VOF-PLIC and CLSVOF to achieve optimum interface accuracy with minimal computational resources. The energy equation is written in terms of enthalpy with an additional source term to account for the phase change. The solidification phenomenon is modeled using a coupled temperature-solute scheme that reflects the microscopic effects arising due to dendritic growth

  6. Computational Modelling of a Tangentially Fired Boiler With Deposit Formation Phenomena

    Directory of Open Access Journals (Sweden)

    Modliński Norbert J.

    2014-09-01

    Full Text Available Any complete CFD model of pulverised coal-fired boiler needs to consider ash deposition phenomena. Wall boundary conditions (temperature and emissivity should be temporally corrected to account for the effects of deposit growth on the combustion conditions. At present voluminous publications concerning ash related problems are available. The current paper presents development of an engineering tool integrating deposit formation models with the CFD code. It was then applied to two tangentially-fired boilers. The developed numerical tool was validated by comparing it with boiler evaporator power variation based on the on-line diagnostic system with the results from the full CFD simulation.

  7. Dynamic Modeling for the Design and Cyclic Operation of an Atomic Layer Deposition (ALD) Reactor

    OpenAIRE

    Travis, Curtisha; Adomaitis, Raymond

    2013-01-01

    A laboratory-scale atomic layer deposition (ALD) reactor system model is derived for alumina deposition using trimethylaluminum and water as precursors. Model components describing the precursor thermophysical properties, reactor-scale gas-phase dynamics and surface reaction kinetics derived from absolute reaction rate theory are integrated to simulate the complete reactor system. Limit-cycle solutions defining continuous cyclic ALD reactor operation are computed with a fixed point algorithm ...

  8. RHEED study of titanium dioxide with pulsed laser deposition

    DEFF Research Database (Denmark)

    Rasmussen, Inge Lise; Pryds, Nini; Schou, Jørgen

    2009-01-01

    Reflection high-energy electron diffraction (RHEED) operated at high pressure has been used to monitor the growth of thin films of titanium dioxide (TiO2) on (1 0 0) magnesium oxide (MgO) substrates by pulsed laser deposition (PLD). The deposition is performed with a synthetic rutile TiO2 target...

  9. A study of wet deposition of atmospheric tritium releases at the Ontario Power Generation, Pickering Nuclear Generating Station

    International Nuclear Information System (INIS)

    Crooks, G.; DeWilde, J.; Yu, L.

    2001-01-01

    The Ontario Power Generation,Pickering Nuclear Generating Station (PNGS) has been investigating deposition of atmospheric releases of tritium on their site. This study has included numerical dispersion modelling studies conducted over the past three years, as well as an ongoing field monitoring study. The following paper will present results of the field monitoring study and make comparisons to the numerical modelling. The results of this study could be of potential use to nuclear stations in quantifying tritium deposition in near field regions where building wake effects dominate pollutant dispersion

  10. Discussion on geochemical characteristics, mechanism and prospecting model of gluey type sandstone uranium mineralization--taking Redwell uranium deposit as an example

    International Nuclear Information System (INIS)

    Wang Jinping

    1998-01-01

    Redwell uranium deposit hosted in the red clastic rock formation, is a typical example of gluey type uranium mineralization, which has not been reported so far in China. Based on the study of geochemical characteristics of Redwell deposit, the author discusses the genetic mechanism of this type deposits, and proposes the prospecting model of 4 in 1 of red bed-fault-oil gas-uranium source

  11. European and Mediterranean mercury modelling: Local and long-range contributions to the deposition flux

    Science.gov (United States)

    Gencarelli, Christian N.; De Simone, Francesco; Hedgecock, Ian M.; Sprovieri, Francesca; Yang, Xin; Pirrone, Nicola

    2015-09-01

    Mercury (Hg) is a global pollutant that is known to have adverse effects on human health, and most human exposure to toxic methylmercury is through fish consumption. Soluble Hg compounds in the marine environment can be methylated in the water column and enter the base of the food chain. Atmospheric deposition is the most important pathway by which Hg enters marine ecosystems. The atmospheric chemistry of Hg has been simulated over Europe and the Mediterranean for the year 2009, using the WRF/Chem model and employing two different gas phase Hg oxidation mechanisms. The contributions to the marine deposition flux from dry deposition, synoptic scale wet deposition and convective wet deposition have been determined. The Hg deposition fluxes resulting from transcontinental transport and local/regional emission sources has been determined using both Br/BrO and O3/OH atmospheric oxidation mechanisms. The two mechanisms give significantly different annual deposition fluxes (129 Mg and 266 Mg respectively) over the modelling domain. Dry deposition is more significant using the O3/OH mechanism, while proportionally convective wet deposition is enhanced using the Br/BrO mechanism. The simulations using the Br/BrO oxidation compared best with observed Hg fluxes in precipitation. Local/regional Hg emissions have the most impact within the model domain during the summer. A comparison of simulations using the 2005 and 2010 AMAP/UNEP Hg emission inventories show that although there is a decrease of 33% in anthropogenic emissions between the two reference years, the total simulated deposition in the regions diminishes by only 12%. Simulations using the 2010 inventory reproduce observations somewhat better than those using the 2005 inventory for 2009.

  12. Joint analysis of deposition fluxes and atmospheric concentrations of inorganic nitrogen and sulphur compounds predicted by six chemistry transport models in the frame of the EURODELTAIII project

    Science.gov (United States)

    Vivanco, M. G.; Bessagnet, B.; Cuvelier, C.; Theobald, M. R.; Tsyro, S.; Pirovano, G.; Aulinger, A.; Bieser, J.; Calori, G.; Ciarelli, G.; Manders, A.; Mircea, M.; Aksoyoglu, S.; Briganti, G.; Cappelletti, A.; Colette, A.; Couvidat, F.; D'Isidoro, M.; Kranenburg, R.; Meleux, F.; Menut, L.; Pay, M. T.; Rouïl, L.; Silibello, C.; Thunis, P.; Ung, A.

    2017-02-01

    In the framework of the UNECE Task Force on Measurement and Modelling (TFMM) under the Convention on Long-range Transboundary Air Pollution (LRTAP), the EURODELTAIII project is evaluating how well air quality models are able to reproduce observed pollutant air concentrations and deposition fluxes in Europe. In this paper the sulphur and nitrogen deposition estimates of six state-of-the-art regional models (CAMx, CHIMERE, EMEP MSC-W, LOTOS-EUROS, MINNI and CMAQ) are evaluated and compared for four intensive EMEP measurement periods (25 Feb-26 Mar 2009; 17 Sep-15 Oct 2008; 8 Jan-4 Feb 2007 and 1-30 Jun 2006). For sulphur, this study shows the importance of including sea salt sulphate emissions for obtaining better model results; CMAQ, the only model considering these emissions in its formulation, was the only model able to reproduce the high measured values of wet deposition of sulphur at coastal sites. MINNI and LOTOS-EUROS underestimate sulphate wet deposition for all periods and have low wet deposition efficiency for sulphur. For reduced nitrogen, all the models underestimate both wet deposition and total air concentrations (ammonia plus ammonium) in the summer campaign, highlighting a potential lack of emissions (or incoming fluxes) in this period. In the rest of campaigns there is a general underestimation of wet deposition by all models (MINNI and CMAQ with the highest negative bias), with the exception of EMEP, which underestimates the least and even overestimates deposition in two campaigns. This model has higher scavenging deposition efficiency for the aerosol component, which seems to partly explain the different behaviour of the models. For oxidized nitrogen, CMAQ, CAMx and MINNI predict the lowest wet deposition and the highest total air concentrations (nitric acid plus nitrates). Comparison with observations indicates a general underestimation of wet oxidized nitrogen deposition by these models, as well as an overestimation of total air concentration for

  13. Clinical and MRI models predicting amyloid deposition in progressive aphasia and apraxia of speech

    Directory of Open Access Journals (Sweden)

    Jennifer L. Whitwell

    2016-01-01

    Full Text Available Beta-amyloid (Aβ deposition can be observed in primary progressive aphasia (PPA and progressive apraxia of speech (PAOS. While it is typically associated with logopenic PPA, there are exceptions that make predicting Aβ status challenging based on clinical diagnosis alone. We aimed to determine whether MRI regional volumes or clinical data could help predict Aβ deposition. One hundred and thirty-nine PPA (n = 97; 15 agrammatic, 53 logopenic, 13 semantic and 16 unclassified and PAOS (n = 42 subjects were prospectively recruited into a cross-sectional study and underwent speech/language assessments, 3.0 T MRI and C11-Pittsburgh Compound B PET. The presence of Aβ was determined using a 1.5 SUVR cut-point. Atlas-based parcellation was used to calculate gray matter volumes of 42 regions-of-interest across the brain. Penalized binary logistic regression was utilized to determine what combination of MRI regions, and what combination of speech and language tests, best predicts Aβ (+ status. The optimal MRI model and optimal clinical model both performed comparably in their ability to accurately classify subjects according to Aβ status. MRI accurately classified 81% of subjects using 14 regions. Small left superior temporal and inferior parietal volumes and large left Broca's area volumes were particularly predictive of Aβ (+ status. Clinical scores accurately classified 83% of subjects using 12 tests. Phonological errors and repetition deficits, and absence of agrammatism and motor speech deficits were particularly predictive of Aβ (+ status. In comparison, clinical diagnosis was able to accurately classify 89% of subjects. However, the MRI model performed well in predicting Aβ deposition in unclassified PPA. Clinical diagnosis provides optimum prediction of Aβ status at the group level, although regional MRI measurements and speech and language testing also performed well and could have advantages in predicting Aβ status in unclassified

  14. Clinical and MRI models predicting amyloid deposition in progressive aphasia and apraxia of speech.

    Science.gov (United States)

    Whitwell, Jennifer L; Weigand, Stephen D; Duffy, Joseph R; Strand, Edythe A; Machulda, Mary M; Senjem, Matthew L; Gunter, Jeffrey L; Lowe, Val J; Jack, Clifford R; Josephs, Keith A

    2016-01-01

    Beta-amyloid (Aβ) deposition can be observed in primary progressive aphasia (PPA) and progressive apraxia of speech (PAOS). While it is typically associated with logopenic PPA, there are exceptions that make predicting Aβ status challenging based on clinical diagnosis alone. We aimed to determine whether MRI regional volumes or clinical data could help predict Aβ deposition. One hundred and thirty-nine PPA (n = 97; 15 agrammatic, 53 logopenic, 13 semantic and 16 unclassified) and PAOS (n = 42) subjects were prospectively recruited into a cross-sectional study and underwent speech/language assessments, 3.0 T MRI and C11-Pittsburgh Compound B PET. The presence of Aβ was determined using a 1.5 SUVR cut-point. Atlas-based parcellation was used to calculate gray matter volumes of 42 regions-of-interest across the brain. Penalized binary logistic regression was utilized to determine what combination of MRI regions, and what combination of speech and language tests, best predicts Aβ (+) status. The optimal MRI model and optimal clinical model both performed comparably in their ability to accurately classify subjects according to Aβ status. MRI accurately classified 81% of subjects using 14 regions. Small left superior temporal and inferior parietal volumes and large left Broca's area volumes were particularly predictive of Aβ (+) status. Clinical scores accurately classified 83% of subjects using 12 tests. Phonological errors and repetition deficits, and absence of agrammatism and motor speech deficits were particularly predictive of Aβ (+) status. In comparison, clinical diagnosis was able to accurately classify 89% of subjects. However, the MRI model performed well in predicting Aβ deposition in unclassified PPA. Clinical diagnosis provides optimum prediction of Aβ status at the group level, although regional MRI measurements and speech and language testing also performed well and could have advantages in predicting Aβ status in unclassified PPA subjects.

  15. 3D modelling of the Plavitsa Au -Cu polymetallic deposit, Republic of Macedonia

    International Nuclear Information System (INIS)

    Ivanovski, Igor; Serafimovski, Dalibor

    2015-01-01

    The latest exploration and study of the high sulfidation epithermal deposit of Plavitsa displayed significant progress in understanding the geology and definition of the particular ore body. The results from boreholes made by Genesis Resources International DOOEL Skopje, Republic of Macedonia, in 2011, 2012 and 2013 were: 51 m interval with 3.9 g/t Au in oxidation zone, 65 m interval with 3.1 g/t Au in oxidation zone, 51 m interval with 3.7 g/t Au, 2.8% Cu and 16 g/t Ag in sulfide zone. For this 3D model all 195 boreholes made by the Genesis Re- sources International were used. The boreholes were made in the period of 2011-2013, with total length of 47295.8 m of which 74 boreholes were performed by diamond core method and total length of 23908.3 m while the other 121 boreholes were performed by rotary circulation (RC) with total length of 23387.5 m. Using professional ArcGIS software were prepared 3D models of the ore body for gold and copper, at respective resolution of 30 m and 10 m, for each element, which have defined mineralization extent from 1305 m to 600 m of the hypsometric level. These models should improve our understanding of the ore mineralization and complement the geological data of the Plavitsa ore deposit. (author)

  16. Accuracy of medical models made by consumer-grade fused deposition modelling printers.

    Science.gov (United States)

    Petropolis, Christian; Kozan, Daniel; Sigurdson, Leif

    2015-01-01

    Additive manufacturing using fused deposition modelling (FDM) has become widely available with the development of consumer-grade three-dimensional printers. To be useful in maxillofacial surgery, models created by these printers must accurately reproduce the craniofacial skeleton. To determine the accuracy of consumer-grade FDM printers in the production of medical models compared with industrial selective laser sintering (SLS) printers. Computed tomography images of a dry skull were manipulated using OsiriX (OsiriX, Switzerland) and ZBrush (Pixologic, USA) software. Models were fabricated using a consumer-grade FDM printer at 100 μm, 250 μm and 500 μm layer heights and an industrial SLS printer. Seven linear measurements were made on the models and compared with the corresponding dry skull measurements using an electronic caliper. A dimensional error of 0.30% was observed for the SLS models and 0.44%, 0.52% and 1.1% for the 100 μm, 250 μm and 500 μm FDM models, respectively. Consumer-grade FDM printers can produce medical models with sufficient dimensional accuracy for use in maxillofacial surgery. With this technology, surgeons can independently produce low-cost maxillofacial models in an office setting.

  17. Accuracy of medical models made by consumer-grade fused deposition modelling printers

    Science.gov (United States)

    Petropolis, Christian; Kozan, Daniel; Sigurdson, Leif

    2015-01-01

    BACKGROUND: Additive manufacturing using fused deposition modelling (FDM) has become widely available with the development of consumer-grade three-dimensional printers. To be useful in maxillofacial surgery, models created by these printers must accurately reproduce the craniofacial skeleton. OBJECTIVE: To determine the accuracy of consumer-grade FDM printers in the production of medical models compared with industrial selective laser sintering (SLS) printers. METHODS: Computed tomography images of a dry skull were manipulated using OsiriX (OsiriX, Switzerland) and ZBrush (Pixologic, USA) software. Models were fabricated using a consumer-grade FDM printer at 100 μm, 250 μm and 500 μm layer heights and an industrial SLS printer. Seven linear measurements were made on the models and compared with the corresponding dry skull measurements using an electronic caliper. RESULTS: A dimensional error of 0.30% was observed for the SLS models and 0.44%, 0.52% and 1.1% for the 100 μm, 250 μm and 500 μm FDM models, respectively. CONCLUSION: Consumer-grade FDM printers can produce medical models with sufficient dimensional accuracy for use in maxillofacial surgery. With this technology, surgeons can independently produce low-cost maxillofacial models in an office setting. PMID:26090349

  18. Spectral and multispectral imaging studies of lunar mantled mare deposits

    Science.gov (United States)

    Blewett, D. T.; Hawke, B. R.; Lucey, P. G.; Bell, J. F., III; Jaumann, R.; Hiesinger, H.; Neukum, G.; Spudis, P. D.

    1993-01-01

    Near-IR reflectance spectra (0.6-2.5 microns) and CCD images in the extended visible range (0.4-1.0 microns) obtained with Earth-based telescopes have been used to investigate the composition and origin of formations in the Schiller-Schickard region of the Moon. Of particular interest are the Schickard light plains, which represent an area of mantled mare basalt, or cryptomare. Here local pre-existing mare basalts were eroded and incorporated into a highlands-rich deposit by eject a from the Orientale Basin. Spectra observations of mature and immature highland and mare surfaces, as well as dark-halo crater materials provide information on the mafic mineralogy of features in the area. Analyses of the '1 micron' absorption band and spectral mixing models indicate that selected spots in the light plains contain on the order of 50 percent mare basalt. CCD image cubes can be used to map the amount of basalt in the light plains and evaluate changes with radial distance from Orientale.

  19. Integrative evaluation of data derived from biomonitoring and models indicating atmospheric deposition of heavy metals.

    Science.gov (United States)

    Nickel, Stefan; Schröder, Winfried

    2017-05-01

    Atmospheric deposition of heavy metals (HM) can be determined by use of numeric models, technical devices and biomonitors. Mainly focussing on Germany, this paper aims at evaluating data from deposition modelling and biomonitoring programmes. The model LOTOS-EUROS (LE) yielded data on HM deposition at a spatial resolution of 25 km by 25 km throughout Europe. The European Monitoring and Evaluation Programme (EMEP) provided model calculations on 50 km by 50 km grids. Corresponding data on HM concentration in moss, leaves and needles and soil were derived from the European Moss Survey (EMS), the German Environmental Specimen Bank (ESB) and the International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (iCP Forests). The modelled HM deposition and respective concentrations in moss (EMS), leaves and needles (ESB, iCP Forests) and soil (iCP Forests) were investigated for their statistical relationships. Regression equations were applied on geostatistical surface estimations of HM concentration in moss and then the residuals were interpolated by use of kriging interpolation. Both maps were summed up to a map of cadmium (Cd) and lead (Pb) deposition across Germany. Biomonitoring data were strongly correlated to LE than to EMEP. For HM concentrations in moss, the highest correlations were found for the association between geostatistical surface estimations of HM concentration in moss and deposition (LE).

  20. Novel Optical Diagnostic Techniques for Studying Particle Deposition Upon Large Cylinders in a Sheared Suspension

    Science.gov (United States)

    Yoda, M.; Bailey, B. C.

    2000-01-01

    On a twelve-month voyage to Mars, one astronaut will require at least two tons of potable water and two tons of pure oxygen. Efficient, reliable fluid reclamation is therefore necessary for manned space exploration. Space habitats require a compact, flexible, and robust apparatus capable of solid-fluid mechanical separation over a wide range of fluid and particle densities and particle sizes. In space, centrifugal filtration, where particles suspended in fluid are captured by rotating fixed-fiber mat filters, is a logical candidate for mechanical separation. Non-colloidal particles are deposited on the fibers due to inertial impaction or direct interception. Since rotation rates are easily adjustable, inertial effects are the most practical way to control separation rates for a wide variety of multiphase mixtures in variable gravity environments. Understanding how fluid inertia and differential fluid-particle inertia, characterized by the Reynolds and Stokes numbers, respectively, affect deposition is critical in optimizing filtration in a microgravity environment. This work will develop non-intrusive optical diagnostic techniques for directly visualizing where and when non-colloidal particles deposit upon, or contact, solid surfaces: 'particle proximity sensors'. To model particle deposition upon a single filter fiber, these sensors will be used in ground-based experiments to study particle dynamics as in the vicinity of a large (compared with the particles) cylinder in a simply sheared (i.e., linearly-varying, zero-mean velocity profile) neutrally-buoyant, refractive-index matched solid-liquid suspension.

  1. Simulation and growing study of Cu–Al–S thin films deposited by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Duclaux, L., E-mail: loraine-externe.duclaux@edf.fr [Institute of Research and Development on Photovoltaic Energy (IRDEP), EDF R& D/CNRS/ChimieParistech, UMR 7174, 6 quai Watier, 78401 Chatou (France); Donsanti, F.; Vidal, J. [Institute of Research and Development on Photovoltaic Energy (IRDEP), EDF R& D/CNRS/ChimieParistech, UMR 7174, 6 quai Watier, 78401 Chatou (France); Bouttemy, M. [Lavoisier Institute of Versailles, UMR 8180, 45 avenue des Etats-Unis, 78035 Versailles cedex (France); Schneider, N.; Naghavi, N. [Institute of Research and Development on Photovoltaic Energy (IRDEP), EDF R& D/CNRS/ChimieParistech, UMR 7174, 6 quai Watier, 78401 Chatou (France)

    2015-11-02

    In this paper, we have explored the potential of Cu–Al–S compounds as p-type transparent conducting material by means of atomistic simulation using CuAlS{sub 2} as a reference ternary compound and atomic layer deposition (ALD) growth. We have identified key intrinsic point defects acting either as shallow acceptor or deep donor which define the conductivity of CuAlS{sub 2}. Higher p-type conductivity was found to be achievable under metal-poor and chalcogen-rich growth conditions. According to this precept, ALD growth of Cu{sub x}Al{sub y}S{sub z} was attempted using Cu(acac){sub 2} and Al(CH{sub 3}){sub 3} as precursors for Cu and Al respectively and under H{sub 2}S atmosphere. While as grown thin films present low content of Al, it influences the band gap values as well as the obtained structures. - Highlights: • Ab-initio investigation of CuAlS{sub 2} • Indentification of two opposite main-contributive intrinsic defects on the conductivity: V{sub Cu} and Al{sub Cu} • Synthesis of Cu-Al-S ternary compound using atomic layer deposition • Impact of aluminum insertion on the optical and structural properties of the films.

  2. Model catalysis by size-selected cluster deposition

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Scott [Univ. of Utah, Salt Lake City, UT (United States)

    2015-11-20

    This report summarizes the accomplishments during the last four years of the subject grant. Results are presented for experiments in which size-selected model catalysts were studied under surface science and aqueous electrochemical conditions. Strong effects of cluster size were found, and by correlating the size effects with size-dependent physical properties of the samples measured by surface science methods, it was possible to deduce mechanistic insights, such as the factors that control the rate-limiting step in the reactions. Results are presented for CO oxidation, CO binding energetics and geometries, and electronic effects under surface science conditions, and for the electrochemical oxygen reduction reaction, ethanol oxidation reaction, and for oxidation of carbon by water.

  3. Iron deposition is independent of cellular inflammation in a cerebral model of multiple sclerosis.

    Science.gov (United States)

    Williams, Rachel; Rohr, Aaron M; Wang, Wen-Tung; Choi, In-Young; Lee, Phil; Berman, Nancy E J; Lynch, Sharon G; LeVine, Steven M

    2011-06-23

    Perivenular inflammation is a common early pathological feature in multiple sclerosis (MS). A recent hypothesis stated that CNS inflammation is induced by perivenular iron deposits that occur in response to altered blood flow in MS subjects. In order to evaluate this hypothesis, an animal model was developed, called cerebral experimental autoimmune encephalomyelitis (cEAE), which presents with CNS perivascular iron deposits. This model was used to investigate the relationship of iron deposition to inflammation. In order to generate cEAE, mice were given an encephalitogen injection followed by a stereotactic intracerebral injection of TNF-α and IFN-γ. Control animals received encephalitogen followed by an intracerebral injection of saline, or no encephalitogen plus an intracerebral injection of saline or cytokines. Laser Doppler was used to measure cerebral blood flow. MRI and iron histochemistry were used to localize iron deposits. Additional histological procedures were used to localize inflammatory cell infiltrates, microgliosis and astrogliosis. Doppler analysis revealed that cEAE mice had a reduction in cerebral blood flow compared to controls. MRI revealed T2 hypointense areas in cEAE animals that spatially correlated with iron deposition around vessels and at some sites of inflammation as detected by iron histochemistry. Vessels with associated iron deposits were distributed across both hemispheres. Mice with cEAE had more iron-labeled vessels compared to controls, but these vessels were not commonly associated with inflammatory cell infiltrates. Some iron-laden vessels had associated microgliosis that was above the background microglial response, and iron deposits were observed within reactive microglia. Vessels with associated astrogliosis were more commonly observed without colocalization of iron deposits. The findings indicate that iron deposition around vessels can occur independently of inflammation providing evidence against the hypothesis that iron

  4. Iron deposition is independent of cellular inflammation in a cerebral model of multiple sclerosis

    Directory of Open Access Journals (Sweden)

    Lee Phil

    2011-06-01

    Full Text Available Abstract Background Perivenular inflammation is a common early pathological feature in multiple sclerosis (MS. A recent hypothesis stated that CNS inflammation is induced by perivenular iron deposits that occur in response to altered blood flow in MS subjects. In order to evaluate this hypothesis, an animal model was developed, called cerebral experimental autoimmune encephalomyelitis (cEAE, which presents with CNS perivascular iron deposits. This model was used to investigate the relationship of iron deposition to inflammation. Methods In order to generate cEAE, mice were given an encephalitogen injection followed by a stereotactic intracerebral injection of TNF-α and IFN-γ. Control animals received encephalitogen followed by an intracerebral injection of saline, or no encephalitogen plus an intracerebral injection of saline or cytokines. Laser Doppler was used to measure cerebral blood flow. MRI and iron histochemistry were used to localize iron deposits. Additional histological procedures were used to localize inflammatory cell infiltrates, microgliosis and astrogliosis. Results Doppler analysis revealed that cEAE mice had a reduction in cerebral blood flow compared to controls. MRI revealed T2 hypointense areas in cEAE animals that spatially correlated with iron deposition around vessels and at some sites of inflammation as detected by iron histochemistry. Vessels with associated iron deposits were distributed across both hemispheres. Mice with cEAE had more iron-labeled vessels compared to controls, but these vessels were not commonly associated with inflammatory cell infiltrates. Some iron-laden vessels had associated microgliosis that was above the background microglial response, and iron deposits were observed within reactive microglia. Vessels with associated astrogliosis were more commonly observed without colocalization of iron deposits. Conclusion The findings indicate that iron deposition around vessels can occur independently of

  5. A Fluid Inclusion Study of the Brookbank Deposit, Northwestern Ontario: A Transition from Mesothermal to Epithermal Gold Deposition

    Directory of Open Access Journals (Sweden)

    Barbara Kowalski

    2018-03-01

    Full Text Available The Brookbank and Cherbourg Zone gold deposits are located in the Beardmore–Geraldton greenstone belt of the Wabigoon Subprovince of the Archean Superior Province of the Canadian Shield. Brookbank is a shear zone deposit, whereas the Cherbourg Zone, joined by a shear zone to the Brookbank, is a fissure vein deposit, presumably formed by the same ore-depositing fluid. A total of 375 fluid inclusions, all with low salinity (generally <1 °C freezing point depression and presence of CO2, from the two deposits were studied. Cross-cutting relationships delineated three stages of vein formation: (1 pre-ore, (2 ore stage and (3 post-ore. Stage 1 inclusions homogenized at ca. 230 °C with low salinity, although at Brookbank a high temperature episode at ca. 360 °C was noted. Stage 2 homogenized at ca. 266 °C at the Cherbourg Zone and over a range 258–269 °C with somewhat higher salinity. Eutectic temperatures indicate that the fluid composition was within the MgCl2-NaCl-H2O system. Fluid immiscibility was prominent in that inclusions homogenized to liquid and vapor at the same temperature were observed. The majority of inclusions from Brookbank homogenized to vapor, whereas those from the Cherbourg Zone homogenized to liquid, marking the transition from mesothermal to epithermal lode gold deposition. Stage 3 fluid inclusions from the Cherbourg Zone homogenized at slightly elevated temperatures and contained fluid possibly representing metastable hydrates of KCl. These post-ore fluids may have been the source of potassium feldspar alteration that overprinted earlier alteration assemblages.

  6. Meso-scale modeling of air pollution transport/chemistry/deposition and its application

    International Nuclear Information System (INIS)

    Kitada, Toshihiro

    2007-01-01

    Transport/chemistry/deposition model for atmospheric trace chemical species is now regarded as an important tool for an understanding of the effects of various human activities, such as fuel combustion and deforestation, on human health, eco-system, and climate and for planning of appropriate control of emission sources. Several 'comprehensive' models have been proposed such as RADM (Chang, et al., 1987), STEM-II (Carmichael, et al., 1986), and CMAQ (Community Multi-scale Air Quality model, e.g., EPA website, 2003); the 'comprehensive' models include not only gas/aerosol phase chemistry but also aqueous phase chemistry in cloud/rain water in addition to the processes of advection, diffusion, wet deposition (mass transfer between aqueous and gas/aerosol phases), and dry deposition. The target of the development of the 'comprehensive' model will be that the model can correctly reproduce mass balance of various chemical species in the atmosphere with keeping adequate accuracy for calculated concentration distributions of chemical species. For the purpose, one of the important problems is a reliable wet deposition modeling, and here, we introduce two types of methods of 'cloud-resolving' and 'non-cloud-resolving' modeling for the wet deposition of pollutants. (author)

  7. A Generic Model for the Resuspension of Multilayer Aerosol Deposits by Turbulent Flow

    International Nuclear Information System (INIS)

    Friess, H.; Yadigaroglu, G.

    2001-01-01

    An idealized lattice structure is considered of multilayer aerosol deposits, where every particle at the deposit surface is associated with a resuspension rate constant depending on a statistically distributed particle parameter and on flow conditions. The response of this generic model is represented by a set of integrodifferential equations. As a first application of the general formalism, the behavior of Fromentin's multilayer model is analyzed, and the model parameters are adapted to experimental data. In addition, improved relations between model parameters and physical input parameters are proposed. As a second application, a method is proposed for building multilayer models by using resuspension rate constants of existing monolayer models. The method is illustrated by a sample of monolayer data resulting from the model of Reeks, Reed, and Hall. Also discussed is the error to be expected if a monolayer resuspension model, which works well for thin aerosol deposits, is applied to thick deposits under the classical monolayer assumption that all deposited particles interact with the fluid at all times

  8. Stratigraphic model deposit Ofi Inf SDZ-2X A1, Jun in block in Orinoco Oil belt

    International Nuclear Information System (INIS)

    Martinez, E.; Sandoval, D.

    2010-01-01

    This work is about the Stratigraphic model deposit O fi I nf SDZ-2X A1, Junin block in Orinoco Oil belt.This model was based on a chrono stratigraphic interpretation and was defined the correlation between the main and secondary surfaces. The wells of the study area pass through the Cambrian, Cretaceous and Miocene sediments. The last is more interesting for the study because of the stratigraphic and sand body surface presence

  9. Mass Deposition Fluxes of Asian Dust to the Bohai Sea and Yellow Sea from Geostationary Satellite MTSAT: A Case Study

    Directory of Open Access Journals (Sweden)

    Qianguang Tu

    2015-11-01

    Full Text Available Windblown dust aerosol plays an important role in marine ecosystems once they are deposited and dissolved. At present, methods for estimating the deposition flux are mainly limited to direct measurements or model outputs. Additionally, satellite remote sensing was often used to estimate the integral dust column concentration (DCC. In this paper, an algorithm is developed to estimate the mass deposition fluxes of Asian dust by satellite. The dust aerosol is identified firstly and then the DCC is derived based on the relationships between the pre-calculated lookup table (LUT and observations from Japanese geostationary Multi-functional Transport Satellites (MTSAT. The LUT is built on the dust cloud and surface parameters by a radiation transfer model Streamer. The average change rate of deposition is derived, which shows an exponential decay dependence on transport time along the pathway. Thus, the deposition flux is acquired via integrating the hourly deposition. This simple algorithm is applied to a dust storm that occurred in the Bohai Sea and Yellow Sea from 1 to 3 March 2008. Results indicate that the properties of the dust cloud over the study area changed rapidly and the mass deposition flux is estimated to be 2.59 Mt.

  10. Simulation study of depositing the carbon film on nanoparticles in the magnetized methane plasma

    Science.gov (United States)

    Mohammadzadeh, Hosein; Pourali, Nima; Ebadi, Zahra

    2018-03-01

    Plasma coating of nanoparticles in low-temperature magnetized methane plasma is studied by a simulation approach. To this end, by using the global model, the electron temperature and concentration of different species considered in this plasma are determined in the center of a capacitively coupled discharge. Then, the plasma-wall transition region in the presence of an oblique magnetic field is simulated by the multi-component fluid description. Nanoparticles with different radii are injected into the transition region and surface deposition and heating models, as well as dynamics and charging models, are employed to examine the coating process. The results of the simulation show that the non-spherical growth of nanoparticles is affected by the presence of the magnetic field, as with passing time, an oscillating increase is seen in the thickness of the film deposited on nanoparticles. Also, it is shown that the uniformity of the deposited film is dependent on the rotation velocity of nanoparticles. Generally, the obtained results imply that the sphericity of nanoparticles and uniformity of the film coated on them are controllable by the magnitude and orientation of the magnetic field.

  11. Modelling photochemical oxidant formation, transport, deposition and exposure of terrestrial ecosystems.

    Science.gov (United States)

    Fowler, D; Cape, J N; Coyle, M; Smith, R I; Hjellbrekke, A G; Simpson, D; Derwent, R G; Johnson, C E

    1999-01-01

    The chemical processes responsible for production of photochemical oxidants within the troposphere have been the subject of laboratory and field study throughout the last three decades. During the same period, models to simulate the atmospheric chemistry, transport and deposition of ozone (O(3)) from individual urban sources and from regions have been developed. The models differ greatly in the complexity of chemical schemes, in the underlying meteorology and in spatial and temporal resolution. Input information from land use, spatial and temporally disaggregated emission inventories and meteorology have all improved considerably in recent years and are not fully implemented in current models. The development of control strategies in both North America and Europe to close the gaps between current exceedances of environmental limits, guide values, critical levels or loads and full compliance with these limits provides the focus for policy makers and the support agencies for the research. The models represent the only method of testing a range of control options in advance of implementation. This paper describes currently applied models of photochemical oxidant production and transport at global and regional scales and their ability to simulate individual episodes as well as photochemical oxidant climatology. The success of current models in quantifying the exposure of terrestrial surfaces and the population to potentially damaging O(3) concentrations (and dose) is examined. The analysis shows the degree to which the underlying processes and their application within the models limit the quality of the model products.

  12. [3D printing personalized implant manufactured via fused deposition modeling: an accuracy research].

    Science.gov (United States)

    Wang, Ning; Li, Jie; Wang, Xiaolong; Liu, Gang; Liu, Bin

    2015-10-01

    The aim of this study was to determine the accuracy of personalized implant fabricated via 3D printing and fused deposition modeling technique (FDM) and to compare the results with a real tooth. Six prepared extracted orthodontic teeth (in vivo) were scanned via cone beam computed tomography (CBCT) to obtain 3D data and to build the data models by using Mimics 15.0 software. The extracted orthodontic teeth (in vitro) and the personalized implants designed via 3D printing and FDM were scanned via CBCT to obtain data and to build the data models at the same parameters. The 3D deviations were compared among the in vivo teeth data models, in vitro teeth data models, and printing personalized implant data models by using the Geomagic studio software. The average deviations of high and low areas between date models of in vivo teeth and personalized implants were 0.19 mm and -0.16 mm, respectively, and the average deviations between in vitro and in vivo teeth were 0.14 mm and -0.07 mm, respectively. The independent t test showed that no statistically significant difference was observed between the two groups (P>0.05). 1) The personalized dental implants were manufactured via 3D printing and FDM with a high degree of precision. 2) Errors between the data models of in vitro and in vivo teeth were observed at the same CBCT parameters.

  13. Experimental Validation of Plastic Mandible Models Produced by a “Low-Cost” 3-Dimensional Fused Deposition Modeling Printer

    Science.gov (United States)

    Maschio, Federico; Pandya, Mirali; Olszewski, Raphael

    2016-01-01

    Background The objective of this study was to investigate the accuracy of 3-dimensional (3D) plastic (ABS) models generated using a low-cost 3D fused deposition modelling printer. Material/Methods Two human dry mandibles were scanned with a cone beam computed tomography (CBCT) Accuitomo device. Preprocessing consisted of 3D reconstruction with Maxilim software and STL file repair with Netfabb software. Then, the data were used to print 2 plastic replicas with a low-cost 3D fused deposition modeling printer (Up plus 2®). Two independent observers performed the identification of 26 anatomic landmarks on the 4 mandibles (2 dry and 2 replicas) with a 3D measuring arm. Each observer repeated the identifications 20 times. The comparison between the dry and plastic mandibles was based on 13 distances: 8 distances less than 12 mm and 5 distances greater than 12 mm. Results The mean absolute difference (MAD) was 0.37 mm, and the mean dimensional error (MDE) was 3.76%. The MDE decreased to 0.93% for distances greater than 12 mm. Conclusions Plastic models generated using the low-cost 3D printer UPplus2® provide dimensional accuracies comparable to other well-established rapid prototyping technologies. Validated low-cost 3D printers could represent a step toward the better accessibility of rapid prototyping technologies in the medical field. PMID:27003456

  14. Experimental Validation of Plastic Mandible Models Produced by a "Low-Cost" 3-Dimensional Fused Deposition Modeling Printer.

    Science.gov (United States)

    Maschio, Federico; Pandya, Mirali; Olszewski, Raphael

    2016-03-22

    The objective of this study was to investigate the accuracy of 3-dimensional (3D) plastic (ABS) models generated using a low-cost 3D fused deposition modelling printer. Two human dry mandibles were scanned with a cone beam computed tomography (CBCT) Accuitomo device. Preprocessing consisted of 3D reconstruction with Maxilim software and STL file repair with Netfabb software. Then, the data were used to print 2 plastic replicas with a low-cost 3D fused deposition modeling printer (Up plus 2®). Two independent observers performed the identification of 26 anatomic landmarks on the 4 mandibles (2 dry and 2 replicas) with a 3D measuring arm. Each observer repeated the identifications 20 times. The comparison between the dry and plastic mandibles was based on 13 distances: 8 distances less than 12 mm and 5 distances greater than 12 mm. The mean absolute difference (MAD) was 0.37 mm, and the mean dimensional error (MDE) was 3.76%. The MDE decreased to 0.93% for distances greater than 12 mm. Plastic models generated using the low-cost 3D printer UPplus2® provide dimensional accuracies comparable to other well-established rapid prototyping technologies. Validated low-cost 3D printers could represent a step toward the better accessibility of rapid prototyping technologies in the medical field.

  15. Organic geochemical study of domanik deposits, Tatarstan Republic.

    Science.gov (United States)

    Nosova, F. F.; Pronin, N. V.

    2010-05-01

    High-bituminous argillo-siliceous carbonate deposits of domanik formation (DF) occurring within pale depressions and down warps in the east of the Russian platform are treated by many investigators as a main source of oil and gas in the Volga-Ural province. In this study a special attention was turned to organic-rich rocks DF witch outcrop in the central part (Uratminskaya area 792, 806 boreholes) and in the west part (Sviyagskaya, 423) of the Tatarstan Republic. The aim of the present paper is to characterize the organic matter: origin, depositional environments, thermal maturity and biodegradation-weathering effects. Nowadays the most informative geochemical parameters are some biomarkers which qualitatively and are quantitatively defined from distributions of n-alkanes and branched alkanes. Biomarkers - it's original fingerprints of biomass of organic matter, that reflect molecular hydrocarbonic structure. The bulk, molecular composition of oil is initially a function of the type and maturity of the source rock from which it has been expelled, while the source rock type reflects both the nature of precursor organisms and the conditions of its deposition. Methodology used in this study included sampling, bitumen extraction, liquid-column chromatography and gas chromatography/mass spectrometry analyses. The bitumen was fractionated by column chromatography on silica gel. Non-aromatic or alifatics, aromatics and polar compounds were obtained. Alifatic were analysed by gas chromatography/mass spectrometry Percin Elmer. The hydrocarbons present in the sediments of DF and have a carbon numbers ranging from 12 through 38. The samples contain variably inputs from both terrigenous and non-terrigenous (probably marine algal) organic matter as evident in bimodal GC fingerprints of some samples. Pristane and phytane, also, occur in very high concentration in sample extracts. The relatively low Pr/Ph ratios, CPI and OEPbiomarkers distribution of the domanic samples generally

  16. The giant Jiaodong gold province: The key to a unified model for orogenic gold deposits?

    Directory of Open Access Journals (Sweden)

    David I. Groves

    2016-05-01

    Full Text Available Although the term orogenic gold deposit has been widely accepted for all gold-only lode-gold deposits, with the exception of Carlin-type deposits and rare intrusion-related gold systems, there has been continuing debate on their genesis. Early syngenetic models and hydrothermal models dominated by meteoric fluids are now clearly unacceptable. Magmatic-hydrothermal models fail to explain the genesis of orogenic gold deposits because of the lack of consistent spatially – associated granitic intrusions and inconsistent temporal relationships. The most plausible, and widely accepted, models involve metamorphic fluids, but the source of these fluids is hotly debated. Sources within deeper segments of the supracrustal successions hosting the deposits, the underlying continental crust, and subducted oceanic lithosphere and its overlying sediment wedge all have their proponents. The orogenic gold deposits of the giant Jiaodong gold province of China, in the delaminated North China Craton, contain ca. 120 Ma gold deposits in Precambrian crust that was metamorphosed over 2000 million years prior to gold mineralization. The only realistic source of fluid and gold is a subducted oceanic slab with its overlying sulfide-rich sedimentary package, or the associated mantle wedge. This could be viewed as an exception to a general metamorphic model where orogenic gold has been derived during greenschist- to amphibolite-facies metamorphism of supracrustal rocks: basaltic rocks in the Precambrian and sedimentary rocks in the Phanerozoic. Alternatively, if a holistic view is taken, Jiaodong can be considered the key orogenic gold province for a unified model in which gold is derived from late-orogenic metamorphic devolatilization of stalled subduction slabs and oceanic sediments throughout Earth history. The latter model satisfies all geological, geochronological, isotopic and geochemical constraints but the precise mechanisms of auriferous fluid release, like many

  17. Modelling and optimization of film thickness variation for plasma enhanced chemical vapour deposition processes

    Science.gov (United States)

    Waddell, Ewan; Gibson, Des; Lin, Li; Fu, Xiuhua

    2011-09-01

    This paper describes a method for modelling film thickness variation across the deposition area within plasma enhanced chemical vapour deposition (PECVD) processes. The model enables identification and optimization of film thickness uniformity sensitivities to electrode configuration, temperature, deposition system design and gas flow distribution. PECVD deposition utilizes a co-planar 300mm diameter electrodes with separate RF power matching to each electrode. The system has capability to adjust electrode separation and electrode temperature as parameters to optimize uniformity. Vacuum is achieved using dry pumping with real time control of butterfly valve position for active pressure control. Comparison between theory and experiment is provided for PECVD of diamond-like-carbon (DLC) deposition onto flat and curved substrate geometries. The process utilizes butane reactive feedstock with an argon carrier gas. Radiofrequency plasma is used. Deposited film thickness sensitivities to electrode geometry, plasma power density, pressure and gas flow distribution are demonstrated. Use of modelling to optimise film thickness uniformity is demonstrated. Results show DLC uniformity of 0.30% over a 200 mm flat zone diameter within overall electrode diameter of 300mm. Thickness uniformity of 0.75% is demonstrated over a 200mm diameter for a non-conformal substrate geometry. Use of the modelling method for PECVD using metal-organic chemical vapour deposition (MOCVD) feedstock is demonstrated, specifically for deposition of silica films using metal-organic tetraethoxy-silane. Excellent agreement between experimental and theory is demonstrated for conformal and non-conformal geometries. The model is used to explore scalability of PECVD processes and trade-off against film thickness uniformity. Application to MEMS, optical coatings and thin film photovoltaics is discussed.

  18. Atmospheric Nitrogen Deposition to the Oceans: Observation- and Model-Based Estimates

    Science.gov (United States)

    Baker, Alex

    2016-04-01

    The reactive nitrogen (Nr) burden of the atmosphere has been increased by a factor of 3-4 by anthropogenic activity since the Industrial Revolution. This has led to large increases in the deposition of nitrate and ammonium to the surface waters of the open ocean, particularly downwind of major human population centres, such as those in North America, Europe and Southeast Asia. In oligotrophic waters, this deposition has the potential to significantly impact marine productivity and the global carbon cycle. Global-scale understanding of N deposition to the oceans is reliant on our ability to produce effective models of reactive nitrogen emission, atmospheric chemistry, transport and deposition (including deposition to the land surface). Over land, N deposition models can be assessed using comparisons to regional monitoring networks of precipitation chemistry (notably those located in North America, Europe and Southeast Asia). No similar datasets exist which would allow observation - model comparisons of wet deposition for the open oceans, because long-term wet deposition records are available for only a handful of remote island sites and rain collection over the open ocean itself is logistically very difficult. In this work we attempt instead to use ~2800 observations of aerosol nitrate and ammonium concentrations, acquired from sampling aboard ships in the period 1995 - 2012, to assess the performance of modelled N deposition fields over the remote ocean. This database is non-uniformly distributed in time and space. We selected three ocean regions (the eastern tropical North Atlantic, the northern Indian Ocean and northwest Pacific) where we considered the density and distribution of observational data is sufficient to provide effective comparison to the model ensemble. Our presentation will focus on the eastern tropical North Atlantic region, which has the best data coverage of the three. We will compare dry deposition fluxes calculated from the observed nitrate

  19. Analyzing the Deposition of Titanium Dioxide Nanoparticles at Model Rough Mineral Surfaces Using a Quartz Crystal Microbalance with Dissipation Monitoring

    Science.gov (United States)

    Li, Y.; Kananizadeh, N.; Rodenhausen, K. B.; Schubert, M.; Bartelt-Hunt, S.

    2015-12-01

    Titanium dioxide nanoparticles (nTiO2) is the most extensively manufactured engineered materials. nTiO2 from sunscreens was found to enter sediments after released into a lake. nTiO2 may also enter the subsurface via irrigation using effluents from wastewater treatment plants. Interaction of nTiO2 with soils and sediments will largely influence their fate, transport, and ecotoxicity. Measuring the interaction between nTiO2 and natural substrates (e.g. such as sands) is particularly challenging due to highly heterogeneous and rough natural sand surfaces. In this study, an engineered controllable rough surface known as three dimensional nanostructured sculptured columnar thin films (SCTFs) has been used to mimic surface roughness. SCTFs were fabricated by glancing angle deposition (GLAD), a physical vapor deposition technique facilitated by electron beam evaporation. Interaction between nTiO2 and SCTF coated surfaces was investigated using a quartz crystal microbalance with dissipation monitoring (QCM-D). In parallel, a Generalized Ellipsometry (GE) was coupled with the QCM-D to measure the deposition of nTiO2. We found that the typical QCM-D modeling approach, e.g. viscoelastic model, would largely overestimate the mass of deposited nTiO2, because the frequency drops due to particle deposition or water entrapment in rough areas were not differentiated. Here, we demonstrate a new approach to model QCM-D data for nTiO2 deposition on rough surfaces, which couples the viscoelastic model with a model of flow on the non-uniform surface.

  20. Model predictions of long-lived storage of organic carbon in river deposits

    Directory of Open Access Journals (Sweden)

    M. A. Torres

    2017-11-01

    Full Text Available The mass of carbon stored as organic matter in terrestrial systems is sufficiently large to play an important role in the global biogeochemical cycling of CO2 and O2. Field measurements of radiocarbon-depleted particulate organic carbon (POC in rivers suggest that terrestrial organic matter persists in surface environments over millennial (or greater timescales, but the exact mechanisms behind these long storage times remain poorly understood. To address this knowledge gap, we developed a numerical model for the radiocarbon content of riverine POC that accounts for both the duration of sediment storage in river deposits and the effects of POC cycling. We specifically target rivers because sediment transport influences the maximum amount of time organic matter can persist in the terrestrial realm and river catchment areas are large relative to the spatial scale of variability in biogeochemical processes.Our results show that rivers preferentially erode young deposits, which, at steady state, requires that the oldest river deposits are stored for longer than expected for a well-mixed sedimentary reservoir. This geometric relationship can be described by an exponentially tempered power-law distribution of sediment storage durations, which allows for significant aging of biospheric POC. While OC cycling partially limits the effects of sediment storage, the consistency between our model predictions and a compilation of field data highlights the important role of storage in setting the radiocarbon content of riverine POC. The results of this study imply that the controls on the terrestrial OC cycle are not limited to the factors that affect rates of primary productivity and respiration but also include the dynamics of terrestrial sedimentary systems.

  1. Thermal analysis of fused deposition modeling process using infrared thermography imaging and finite element modeling

    Science.gov (United States)

    Zhou, Xunfei; Hsieh, Sheng-Jen

    2017-05-01

    After years of development, Fused Deposition Modeling (FDM) has become the most popular technique in commercial 3D printing due to its cost effectiveness and easy-to-operate fabrication process. Mechanical strength and dimensional accuracy are two of the most important factors for reliability of FDM products. However, the solid-liquid-solid state changes of material in the FDM process make it difficult to monitor and model. In this paper, an experimental model was developed to apply cost-effective infrared thermography imaging method to acquire temperature history of filaments at the interface and their corresponding cooling mechanism. A three-dimensional finite element model was constructed to simulate the same process using element "birth and death" feature and validated with the thermal response from the experimental model. In 6 of 9 experimental conditions, a maximum of 13% difference existed between the experimental and numerical models. This work suggests that numerical modeling of FDM process is reliable and can facilitate better understanding of bead spreading and road-to-road bonding mechanics during fabrication.

  2. Effects of generation time on spray aerosol transport and deposition in models of the mouth-throat geometry.

    Science.gov (United States)

    Worth Longest, P; Hindle, Michael; Das Choudhuri, Suparna

    2009-06-01

    For most newly developed spray aerosol inhalers, the generation time is a potentially important variable that can be fully controlled. The objective of this study was to determine the effects of spray aerosol generation time on transport and deposition in a standard induction port (IP) and more realistic mouth-throat (MT) geometry. Capillary aerosol generation (CAG) was selected as a representative system in which spray momentum was expected to significantly impact deposition. Sectional and total depositions in the IP and MT geometries were assessed at a constant CAG flow rate of 25 mg/sec for aerosol generation times of 1, 2, and 4 sec using both in vitro experiments and a previously developed computational fluid dynamics (CFD) model. Both the in vitro and numerical results indicated that extending the generation time of the spray aerosol, delivered at a constant mass flow rate, significantly reduced deposition in the IP and more realistic MT geometry. Specifically, increasing the generation time of the CAG system from 1 to 4 sec reduced the deposition fraction in the IP and MT geometries by approximately 60 and 33%, respectively. Furthermore, the CFD predictions of deposition fraction were found to be in good agreement with the in vitro results for all times considered in both the IP and MT geometries. The numerical results indicated that the reduction in deposition fraction over time was associated with temporal dissipation of what was termed the spray aerosol "burst effect." Based on these results, increasing the spray aerosol generation time, at a constant mass flow rate, may be an effective strategy for reducing deposition in the standard IP and in more realistic MT geometries.

  3. Modeling of stable and metastable structures of Co, Cr, or Fe deposited on Ag(100) substrates

    Energy Technology Data Exchange (ETDEWEB)

    Canzian, A. [Grupo de Caracterizacion y Modelacion de Materiales, UTN, FRGP, H. Yrigoyen 288, (B1617FRP) Gral. Pacheco (Argentina); Bozzolo, G., E-mail: guille_bozzolo@yahoo.co [Loyola University of Maryland, 4501 N. Charles St, Baltimore, MD 21210 (United States); Mosca, H.O. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica, Av. Gral. Paz 1499 (B1650KNA), San Martin (Argentina)

    2011-01-31

    Atomistic modeling of the deposition of Co, Cr, or Fe on a Ag(100) substrate is performed using the Bozzolo-Ferrante-Smith method for alloys, in order to describe the similarities and differences between the three cases. An atom-by-atom description of the deposition process explains the growth patterns from an early stage, establishing a criterion for the determination of the ensuing growth modes.

  4. Control of remediation of uranium deposit Straz with use of numerical modelling approach

    International Nuclear Information System (INIS)

    Novak, J.; Muzak, J.; Smetana, R.

    2002-01-01

    The chemical mining of uranium on the deposit Straz has caused large contamination of groundwater of cretaceous collectors in Straz block of Northbohemian cretaceous table. The low cenomanian aquifer where the uranium deposit is placed is mainly afflicted. In the cenomanian collector there is now more than 4.8 mil. t dissolved solids mainly SO 4 2- , Al, Fe, NH 4 + etc. The total salinity reaches up to 80 g/l. The upper laying turonian collector is drinking water reservoir for larger region. Its contamination is weaker than in cenomanian collector. Use of complex 3D Transport - Reaction Model can be divided into two separate parts. First modelling step is a quantification of overflow between individual mesh elements calculated out of calibrated mixed-hybrid flow model. Two different types of mathematical models are used to accomplish the task: Flow model based on a primary formulation of finite element method, which calculates spatial distribution of piezometric head and flow velocity vectors in selected points of area considered (finite element mesh nodes). This model exactly describes hydraulic situation in area studied; Flow model based on mixed-hybrid formulation of finite element method. This model strictly complies with exact water balance at inter-element faces. In the second part transport-reaction model based on finite volume method is used for calculations using pre-calculated advective velocity field in the area considered. The finite-element mesh covering about 40 km 2 consists of about 16,000 spatial elements. In the leaching fields area the length of the triangular edge is 100-150 meters, vertically the horizon is split into 9-13 layers. The geological boundary-lines were constructed from a database containing information about almost 10 thousand wells. Permeability parameters are defined on the bases of hydrogeological model calculations (calibration) and their vertical distribution is defined more precisely using the GTIS (Geotechnological

  5. Comparison of Modeled and Observed Sulfur Wet Depositions in China; Higashiajia no tairiku chiiki wo taisho to shita iosankabutsu no shisseichinchaku shumyureshon to jissokuchi tono hikaku

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, Takahisa; Hayashi, Masayasu [Environmental Assessment Dept., Tokyo (Japan). Inter-spheic Environment Div.; Wang, Zifa. [Chinese Academy of Sciences, Tokyo (Japan). Institute of Atmospheric Physics

    1999-02-25

    A modeling of the transport and wt deposition of sulfur oxides in the continental areas of East Asia has been introduced. The calculated wet depositions have been compared with the monthly averaged SO{sub 4}{sup 2-} concentrations in precipitation observed at 69 locations widely covering China from July through December of 1992. Calculated values including temporal variations was in reasonable agreement with the observations at most locations except in winter, when he wet depositions were overestimated especially in northern areas. A sensitivity study has been introduced to investigate the reason of the overestimation. A total overview of the distribution of the calculated wet deposition was also indicated. (author)

  6. Tracing contaminant pathways in sandy heterogeneous glaciofluvial sediments using a sedimentary depositional model

    International Nuclear Information System (INIS)

    Webb, E.K.; Anderson, M.P.

    1990-01-01

    Heterogeneous sedimentary deposits present complications for tracking contaminant movement by causing a complex advective flow field. Connected areas of high conductivity produce so-called fast paths that control movement of solutes. Identifying potential fast paths and describing the variation in hydraulic properties was attempted through simulating the deposition of a glaciofluvial deposit (outwash). Glaciofluvial deposits usually consist of several depositional facies, each of which has different physical characteristics, depositional structures and hydraulic properties. Therefore, it is unlikely that the property of stationarity (a constant mean hydraulic conductivity and a mono-modal probability distribution) holds for an entire glaciofluvial sequence. However, the process of dividing an outwash sequence into geologic facies presumably identifies units of material with similar physical characteristics. It is proposed that patterns of geologic facies determined by field observation can be quantified by mathematical simulation of sediment deposition. Subsequently, the simulated sediment distributions can be used to define the distribution of hydrogeologic parameters and locate possible fast paths. To test this hypothesis, a hypothetical glacial outwash deposit based on geologic facies descriptions contained in the literature was simulated using a sedimentary depositional model, SEDSIM, to produce a three-dimensional description of sediment grain size distributions. Grain size distributions were then used to estimate the spatial distribution of hydraulic conductivity. Subsequently a finite-difference flow model and linked particle tracking algorithm were used to trace conservative transport pathways. This represents a first step in describing the spatial heterogeneity of hydrogeologic characteristics for glaciofluvial and other braided stream environments. (Author) (39 refs., 7 figs.)

  7. Simulation study on insoluble granular corrosion products deposited in PWR core

    International Nuclear Information System (INIS)

    Yang Xu; Zhou Tao; Ru Xiaolong; Lin Daping; Fang Xiaolu

    2014-01-01

    In the operation of reactor, such as fuel rods, reactor vessel internals etc. will be affected by corrosion erosion of high pressure coolant. It will produce many insoluble corrosion products. The FLUENT software is adopted to simulate insoluble granular corrosion products deposit distribution in the reactor core. The fluid phase uses the standard model to predict the flow field in the channel and forecast turbulence variation in the near-wall region. The insoluble granular corrosion products use DPM (Discrete Phase Model) to track the trajectory of the particles. The discrete phase model in FLUENT follows the Euler-Lagrange approach. The fluid phase is treated as a continuum by solving the Navier-Stokes equations, while the dispersed phase is solved by tracking a large number of particles through the calculated flow field. Through the study found, Corrosion products particles form high concentration area near the symmetry, and the entrance section of the corrosion products particles concentration is higher than export section. Corrosion products particles deposition attached on large area for the entrance of the cladding, this will change the core neutron flux distribution and the thermal conductivity of cladding material, and cause core axial offset anomaly (AOA). Corrosion products particles dot deposit in the outlet of cladding, which can lead to pitting phenomenon in a sheath. Pitting area will cause deterioration of heat transfer, destroy the cladding integrity. In view of the law of corrosion products deposition and corrosion characteristics of components in the reactor core. this paper proposes regular targeted local cleanup and other mitigation measures. (authors)

  8. A CFD STUDY OF DEPOSITION OF PHARMACEUTICAL AEROSOLS UNDER DIFFERENT RESPIRATORY CONDITIONS

    Directory of Open Access Journals (Sweden)

    L. L. X. Augusto

    Full Text Available Abstract Respiratory diseases have received increasing attention in recent decades. Airway bifurcations are difficult regions to study, and computational fluid dynamics (CFD offers an alternative way of evaluating the behavior of pharmaceutical aerosols used in the treatment of respiratory disorders. In this work, particle deposition was analyzed using a three-dimensional model with four ramifications (three bifurcations, under different respiratory conditions: inhalation, exhalation, and breath holding. The main aim of the work was to verify the medical recommendation to hold one's breath during a few seconds after inhaling pharmaceutical aerosols, rather than exhaling immediately after the inhalation. The deposition of particles with 5 µm diameter was considered. The results showed that the number of aerosols collected on the airway walls was higher for the situation of breath holding, which supported the medical recommendation.

  9. Influence of the Flexible Liposomes on the Skin Deposition of a Hydrophilic Model Drug, Carboxyfluorescein: Dependency on Their Composition

    Science.gov (United States)

    Badran, Mohamed; Shalaby, Khaled; Al-Omrani, Abdullah

    2012-01-01

    This study focuses on the effect of different flexible liposomes containing sodium cholate, Tween 80, or cineol on skin deposition of carboxyfluorescein (CF). Size distribution, morphology, zeta potential, and stability of the prepared vesicles were evaluated. The influence of these systems on the skin deposition of CF utilizing rat skin as membrane model was investigated. Results showed that all of the investigated liposomes had almost spherical shapes with low polydispersity (PDI cineole, were able to deliver higher amount of CF suggesting that the hydrophilic drugs delivery to the skin was strictly correlated to the vesicle composition. PMID:22536120

  10. Outcrop - core correlation and seismic modeling of the Athabasca Oil Sands Deposit, Fort McMurray area, northeast Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Hein, F.J. [Alberta Geological Survey, Calgary, AB (Canada); Langenberg, C.W.; Cotterill, D.C.; Berhane, H. [Alberta Geological Survey, Edmonton, AB (Canada); Lawton, D.; Cunningham, J. [Calgary Univ., AB (Canada)

    1999-11-01

    A joint study between the Alberta Geological Survey and the University of Calgary was conducted which involved a detailed facies analysis of cores and outcrops from the Athabasca Oil Sands Deposit in Alberta`s Steepbank area. A unified facies classification for the deposit was developed. Larger scale facies associations were also determined, as well as proxy sonic logs for outcrops used in seismic modeling. The cores which were displayed exhibited detailed sedimentological and stratigraphic analysis of 10 outcrops in the area. 7 refs.

  11. Predictive modeling capabilities from incident powder and laser to mechanical properties for laser directed energy deposition

    Science.gov (United States)

    Shin, Yung C.; Bailey, Neil; Katinas, Christopher; Tan, Wenda

    2018-01-01

    This paper presents an overview of vertically integrated comprehensive predictive modeling capabilities for directed energy deposition processes, which have been developed at Purdue University. The overall predictive models consist of vertically integrated several modules, including powder flow model, molten pool model, microstructure prediction model and residual stress model, which can be used for predicting mechanical properties of additively manufactured parts by directed energy deposition processes with blown powder as well as other additive manufacturing processes. Critical governing equations of each model and how various modules are connected are illustrated. Various illustrative results along with corresponding experimental validation results are presented to illustrate the capabilities and fidelity of the models. The good correlations with experimental results prove the integrated models can be used to design the metal additive manufacturing processes and predict the resultant microstructure and mechanical properties.

  12. Mineral-deposit model for lithium-cesium-tantalum pegmatites

    Science.gov (United States)

    Bradley, Dwight C.; McCauley, Andrew D.; Stillings, Lisa L.

    2017-06-20

    Lithium-cesium-tantalum (LCT) pegmatites comprise a compositionally defined subset of granitic pegmatites. The major minerals are quartz, potassium feldspar, albite, and muscovite; typical accessory minerals include biotite, garnet, tourmaline, and apatite. The principal lithium ore minerals are spodumene, petalite, and lepidolite; cesium mostly comes from pollucite; and tantalum mostly comes from columbite-tantalite. Tin ore as cassiterite and beryllium ore as beryl also occur in LCT pegmatites, as do a number of gemstones and high-value museum specimens of rare minerals. Individual crystals in LCT pegmatites can be enormous: the largest spodumene was 14 meters long, the largest beryl was 18 meters long, and the largest potassium feldspar was 49 meters long.Lithium-cesium-tantalum pegmatites account for about one-fourth of the world’s lithium production, most of the tantalum production, and all of the cesium production. Giant deposits include Tanco in Canada, Greenbushes in Australia, and Bikita in Zimbabwe. The largest lithium pegmatite in the United States, at King’s Mountain, North Carolina, is no longer being mined although large reserves of lithium remain. Depending on size and attitude of the pegmatite, a variety of mining techniques are used, including artisanal surface mining, open-pit surface mining, small underground workings, and large underground operations using room-and-pillar design. In favorable circumstances, what would otherwise be gangue minerals (quartz, potassium feldspar, albite, and muscovite) can be mined along with lithium and (or) tantalum as coproducts.Most LCT pegmatites are hosted in metamorphosed supracrustal rocks in the upper greenschist to lower amphibolite facies. Lithium-cesium-tantalum pegmatite intrusions generally are emplaced late during orogeny, with emplacement being controlled by pre-existing structures. Typically, they crop out near evolved, peraluminous granites and leucogranites from which they are inferred to be

  13. Multi-model mean nitrogen and sulfur deposition from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP: evaluation of historical and projected future changes

    Directory of Open Access Journals (Sweden)

    J.-F. Lamarque

    2013-08-01

    all the RCPs. The new ACCMIP multi-model deposition dataset provides state-of-the-science, consistent and evaluated time slice (spanning 1850–2100 global gridded deposition fields for use in a wide range of climate and ecological studies.

  14. Multi-model mean nitrogen and sulfur deposition from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP): evaluation of historical and projected future changes

    Science.gov (United States)

    Lamarque, J.-F.; Dentener, F.; McConnell, J.; Ro, C.-U.; Shaw, M.; Vet, R.; Bergmann, D.; Cameron-Smith, P.; Dalsoren, S.; Doherty, R.; Faluvegi, G.; Ghan, S. J.; Josse, B.; Lee, Y. H.; MacKenzie, I. A.; Plummer, D.; Shindell, D. T.; Skeie, R. B.; Stevenson, D. S.; Strode, S.; Zeng, G.; Curran, M.; Dahl-Jensen, D.; Das, S.; Fritzsche, D.; Nolan, M.

    2013-08-01

    ACCMIP multi-model deposition dataset provides state-of-the-science, consistent and evaluated time slice (spanning 1850-2100) global gridded deposition fields for use in a wide range of climate and ecological studies.

  15. Defects study of hydrogenated amorphous silicon samples and their relation with the substrate and deposition conditions

    International Nuclear Information System (INIS)

    Darwich, R.

    2009-07-01

    The goal of this work is to study the properties of the defects aiming to explore the types of defects and the effect of various deposition parameters such as substrate temperature, the kind of the substrate, gas pressure and deposition rate. Two kinds of samples have been used; The first one was a series of Schottky diodes, and the second one a series of solar cells (p-i-n junction) deposited on crystalline silicon or on corning glass substrates with different deposition parameters. The deposition parameters were chosen to obtain materials whose their structures varying from amorphous to microcrystalline silicon including polymorphous silicon. Our results show that the polymorphous silicon samples deposited at high deposition rates present the best photovoltaic properties in comparison with those deposited at low rates. Also we found that the defects concentration in high deposition rate samples is less at least by two orders than that obtained in low deposition rate polymorphous, microcrystalline and amorphous samples. This study shows also that there is no effect of the substrate, or the thin films of highly doped amorphous silicon deposited on the substrate, on the creation and properties of these defects. Finally, different experimental methods have been used; a comparison between their results has been presented. (author)

  16. Global deposition and transport efficiencies of radioactive species with respect to modelling credibility after Fukushima (Japan, 2011)

    International Nuclear Information System (INIS)

    Evangeliou, Nikolaos; Balkanski, Yves; Florou, Heleni; Eleftheriadis, Konstantinos; Cozic, Anne; Kritidis, Panayotis

    2015-01-01

    In this study we conduct a detailed comparison of the modelling response of the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident with global and local observations. We use five different model versions characterized by different horizontal and vertical resolutions of the same General Circulation Model (GCM). Transport efficiencies of 137 Cs across the world are presented as an indication of the expected radioactive impact. Activity concentrations were well represented showing lower Normalized Mean Biases (NMBs) when the better resolved versions of the GCM were used. About 95% of the results using the zoom configuration over Europe (zEur) remained within a factor of 10 from the observations. Close to Japan, the model reproduced well 137 Cs concentrations using the zoom version over Asia (zAsia) showing high correlations, while more than 64% of the modelling results were found within a factor of two from the observations and more than 92% within a factor of 10. Labile and refractory rare radionuclides calculated indirectly showed larger deviations, with about 60% of the simulated concentrations within a factor of 10 from the observations. We estimate that around 23% of the released 137 Cs remained into Japan, while 76% deposited in the oceans. Around 163 TBq deposited over North America, among which 95 TBq over USA, 40 TBq over Canada and 5 TBq over Greenland). About 14 TBq deposited over Europe (mostly in the European part of Russia, Sweden and Norway) and 47 TBq over Asia (mostly in the Asian part of Russia, Philippines and South Korea), while traces were observed over Africa, Oceania and Antarctica. Since the radioactive plume followed a northward direction before its arrival to USA and then to Europe, a significant amount of about 69 TBq deposited in the Arctic, as well. These patterns of deposition are fully consistent with the most recent reports for the accident. - Highlights: • 5 versions of an Eulerian model were used to simulate the Fukushima

  17. Modelling the effects of atmospheric sulphur and nitrogen deposition on selected lakes and streams of the Central Alps (Italy

    Directory of Open Access Journals (Sweden)

    M. Rogora

    2003-01-01

    Full Text Available The dynamic model MAGIC was calibrated and applied to selected sites in north-western Italy (3 rivers, 10 alpine lakes to predict the future response of surface water to different scenarios of atmospheric deposition of S and N compounds. Results at the study sites suggest that several factors other than atmospheric deposition may influence the long-term changes in surface water chemistry. At present the lumped approach of dynamic models such as MAGIC cannot represent all the processes occurring at the catchment scale. Climate warming in particular and its effects on surface water chemistry proved to be important in the study area. Furthermore the river catchments considered here showed clear signs of N saturation. This condition and the increasing concentrations of NO3 in river water were simulated using N dynamics recently included in MAGIC. The modelling performed in this study represents the first application of MAGIC to Italian sites. The results show that inclusion of other factors specific to the Mediterranean area, such as dust deposition and climate change, may improve the fit to observed data and the reliability of the model forecast. Despite these limitations, the model captured well the main trends in chemical data in both rivers and lakes. The outputs clearly demonstrate the benefits of achieving the emission reductions in both S and N compounds as agreed under the Gothenburg Protocol rather than making no further emission reductions. It was also clear that, besides the substantial reduction of SO4 deposition from the peak levels of the 1980s, N deposition must also be reduced in the near future to protect freshwaters from further acidification. Keywords: MAGIC, northern Italy, acidification, recovery, nitrogen saturation

  18. 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

  19. A MECHANISTIC MODEL FOR PARTICLE DEPOSITION IN DIESEL PARTICLUATE FILTERS USING THE LATTICE-BOLTZMANN TECHNIQUE

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, Mark L.; Rector, David R.; Muntean, George G.; Maupin, Gary D.

    2004-08-01

    Cordierite diesel particulate filters (DPFs) offer one of the most promising aftertreatment technologies to meet the quickly approaching EPA 2007 heavy-duty emissions regulations. A critical, yet poorly understood, component of particulate filter modeling is the representation of soot deposition. The structure and distribution of soot deposits upon and within the ceramic substrate directly influence many of the macroscopic phenomenon of interest, including filtration efficiency, back pressure, and filter regeneration. Intrinsic soot cake properties such as packing density and permeability coefficients remain inadequately characterized. The work reported in this paper involves subgrid modeling techniques which may prove useful in resolving these inadequacies. The technique involves the use of a lattice Boltzmann modeling approach. This approach resolves length scales which are orders of magnitude below those typical of a standard computational fluid dynamics (CFD) representation of an aftertreatment device. Individual soot particles are introduced and tracked as they move through the flow field and are deposited on the filter substrate or previously deposited particles. Electron micrographs of actual soot deposits were taken and compared to the model predictions. Descriptions of the modeling technique and the development of the computational domain are provided. Preliminary results are presented, along with some comparisons with experimental observations.

  20. SEM and XPS study of layer-by-layer deposited polypyrrole thin films

    Science.gov (United States)

    Pigois-Landureau, E.; Nicolau, Y. F.; Delamar, M.

    1996-01-01

    Layer-by-layer deposition of thin films (a few nm) of polypyrrole was carried out on various substrates such as silver, platinum, electrochemically oxidized aluminum and pretreated glass. SEM micrographs showed that the deposited layers nucleate by an island-type mechanism on hydrated alumina and KOH-pretreated (hydrophilic) glass before forming a continuous film. However, continuous thin films are obtained on chromic acid pretreated (hydrophobic) glass and sputtered Ag or Pt on glass after only 3-4 deposition cycles. The mean deposition rate evaluated by XPS for the first deposition cycles on Ag and Pt is 3 and 4 nm/cycle, respectively, in agreement with previous gravimetric determinations on thicker films, proving the constancy of the deposition rate. The XPS study of the very thin films obtained by a few deposition cycles shows that the first polypyrrole layers are dedoped by hydroxydic (basic) substrate surfaces.

  1. SEM and XPS study of layer-by-layer deposited polypyrrole thin films

    International Nuclear Information System (INIS)

    Pigois-Landureau, E.; Nicolau, Y.F.; Delamar, M.

    1996-01-01

    Layer-by-layer deposition of thin films (a few nm) of polypyrrole was carried out on various substrates such as silver, platinum, electrochemically oxidized aluminum and pretreated glass. SEM micrographs showed that the deposited layers nucleate by an island-type mechanism on hydrated alumina and KOH-pretreated (hydrophilic) glass before forming a continuous film. However, continuous thin films are obtained on chromic acid pretreated (hydrophobic) glass and sputtered Ag or Pt on glass after only 3 endash 4 deposition cycles. The mean deposition rate evaluated by XPS for the first deposition cycles on Ag and Pt is 3 and 4 nm/cycle, respectively, in agreement with previous gravimetric determinations on thicker films, proving the constancy of the deposition rate. The XPS study of the very thin films obtained by a few deposition cycles shows that the first polypyrrole layers are dedoped by hydroxydic (basic) substrate surfaces. copyright 1996 American Institute of Physics

  2. ELLIPSOMETRIC STUDY OF SEMITRANSPARENT SILVER LAYERS DEPOSITED ON GLASS

    Directory of Open Access Journals (Sweden)

    Víctor Toranzos

    2014-12-01

    Full Text Available Using ellipsometry, the film structure is characterized by optical indices n, k (visible region, 450 nm <  < 580 nm and the thickness (15 < d < 35 nm. The optical indices change with the quantity of silver deposited, obtaining effective indices of 1.0 < n < 1.8 and 1.6 < k < 2.6 to the smaller deposits that belong to a volumetric fraction between 0.35 and 0.5 of silver in the air. An effective optical thickness film decrease is observed when the silver volumetric fraction increases, and a thickness increase with close indices to solid silver when the deposited silver increases. Optical and effective medium theory indices are compared.

  3. Modelling nitrogen saturation and carbon accumulation in heathland soils under elevated nitrogen deposition

    International Nuclear Information System (INIS)

    Evans, C.D.; Caporn, S.J.M.; Carroll, J.A.; Pilkington, M.G.; Wilson, D.B.; Ray, N.; Cresswell, N.

    2006-01-01

    A simple model of nitrogen (N) saturation, based on an extension of the biogeochemical model MAGIC, has been tested at two long-running heathland N manipulation experiments. The model simulates N immobilisation as a function of organic soil C/N ratio, but permits a proportion of immobilised N to be accompanied by accumulation of soil carbon (C), slowing the rate of C/N ratio change and subsequent N saturation. The model successfully reproduced observed treatment effects on soil C and N, and inorganic N leaching, for both sites. At the C-rich upland site, N addition led to relatively small reductions in soil C/N, low inorganic N leaching, and a substantial increase in organic soil C. At the C-poor lowland site, soil C/N ratio decreases and N leaching increases were much more dramatic, and soil C accumulation predicted to be smaller. The study suggests that (i) a simple model can effectively simulate observed changes in soil and leachate N; (ii) previous model predictions based on a constant soil C pool may overpredict future N leaching; (iii) N saturation may develop most rapidly in dry, organic-poor, high-decomposition systems; and (iv) N deposition may lead to significantly enhanced soil C sequestration, particularly in wet, nutrient-poor, organic-rich systems. - Enhanced carbon sequestration may slow the rate of nitrogen saturation in heathlands

  4. Comparing i-Tree modeled ozone deposition with field measurements in a periurban Mediterranean forest

    Science.gov (United States)

    A. Morani; D. Nowak; S. Hirabayashi; G. Guidolotti; M. Medori; V. Muzzini; S. Fares; G. Scarascia Mugnozza; C. Calfapietra

    2014-01-01

    Ozone flux estimates from the i-Tree model were compared with ozone flux measurements using the Eddy Covariance technique in a periurban Mediterranean forest near Rome (Castelporziano). For the first time i-Tree model outputs were compared with field measurements in relation to dry deposition estimates. Results showed generally a...

  5. Boiling of water in flow restricted areas modeled by colloidal silica deposits

    International Nuclear Information System (INIS)

    Peixinho, Jorge; Lefevre, Gregory; Coudert, Francois-Xavier; Hurisse, Olivier

    2012-09-01

    Understanding the effects of particle deposits on evaporation and boiling of water represents an important issue for EDF because it causes a severe reduction in efficiency particularly in steam generators of pressurized water reactor. These deposits are made of oxide metallic particles and the deposition process depends on multiple factors. Here we mimic deposits using a simple system made of hydrophilic silica particles. The present study reports experiments on evaporation or boiling of water confined in the pores of colloidal mono-dispersed silica micro-sphere deposits. The boiling of water confined in the pores of the colloidal crystal is studied using optical microscopy, scanning electron microscopy, nitrogen adsorption, water adsorption through infrared attenuated total reflectance spectroscopy, differential scanning calorimetry and thermal gravimetric analysis. By comparison of the results with silica deposits and alumina membranes with cylindrical pores, our study shows that the morphology of the pores contributes to the evaporation and boiling of water. The measurements suggest that particle resuspension and crust formation take place during drying at elevated temperature and are responsible for cracks formation within the deposit film. (authors)

  6. Deposition of reactive nitrogen during the Rocky Mountain Airborne Nitrogen and Sulfur (RoMANS) study

    International Nuclear Information System (INIS)

    Beem, Katherine B.; Raja, Suresh; Schwandner, Florian M.; Taylor, Courtney; Lee, Taehyoung; Sullivan, Amy P.; Carrico, Christian M.; McMeeking, Gavin R.; Day, Derek; Levin, Ezra; Hand, Jenny; Kreidenweis, Sonia M.; Schichtel, Bret; Malm, William C.; Collett, Jeffrey L.

    2010-01-01

    Increases in reactive nitrogen deposition are a growing concern in the U.S. Rocky Mountain west. The Rocky Mountain Airborne Nitrogen and Sulfur (RoMANS) study was designed to improve understanding of the species and pathways that contribute to nitrogen deposition in Rocky Mountain National Park (RMNP). During two 5-week field campaigns in spring and summer of 2006, the largest contributor to reactive nitrogen deposition in RMNP was found to be wet deposition of ammonium (34% spring and summer), followed by wet deposition of nitrate (24% spring, 28% summer). The third and fourth most important reactive nitrogen deposition pathways were found to be wet deposition of organic nitrogen (17%, 12%) and dry deposition of ammonia (14%, 16%), neither of which is routinely measured by air quality/deposition networks operating in the region. Total reactive nitrogen deposition during the spring campaign was determined to be 0.45 kg ha -1 and more than doubled to 0.95 kg ha -1 during the summer campaign. - The reactive nitrogen deposition budget for Rocky Mountain National Park.

  7. Study of ion implantation in grown layers of multilayer coatings under ion-plasma vacuum deposition

    International Nuclear Information System (INIS)

    Voevodin, A.A.; Erokhin, A.L.

    1993-01-01

    The model of ion implantation into growing layers of a multilayer coating produced with vacuum ion-plasma deposition was developed. The model takes into account a possibility for ions to pass through the growing layer and alloys to find the distribution of implanted atoms over the coating thickness. The experimental vitrification of the model was carried out on deposition of Ti and TiN coatings

  8. Modeling film uniformity and symmetry in ionized metal physical vapor deposition with cylindrical targets

    International Nuclear Information System (INIS)

    Lu Junqing; Yang Lin; Yoon, Jae Hong; Cho, Tong Yul; Tao Guoqing

    2008-01-01

    Severe asymmetry of the metal deposits on the trench sidewalls occurs near the wafer edge during low pressure ionized metal physical vapor deposition of Cu seed layer for microprocessor interconnects. To investigate this process and mitigate the asymmetry, an analytical view factor model based on the analogy between metal sputtering and diffuse thermal radiation was constructed to investigate deposition uniformity and symmetry for cylindrical target sputtering in low pressure (below 0.1 Pa) ionized Cu physical vapor deposition. The model predictions indicate that as the distance from the cylindrical target to wafer increases, the metal film thickness becomes more uniform across the wafer and the asymmetry of the metal deposits at the wafer edge increases significantly. These trends are similar to those for planar targets. To minimize the asymmetry, the height of the cylindrical target should be kept at a minimum. For cylindrical targets, the outward-facing sidewall of the trench could receive more direct Cu fluxes than the inward-facing one when the target to wafer distance is short. The predictions also indicate that increasing the diameter of the cylindrical target could significantly reduce the asymmetry in metal deposits at the wafer edge and make the film thickness more uniform across the wafer

  9. The integrated forest study on effects of atmospheric deposition; A status report

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, D.W.; Lindberg, S.E.; Bondietti, E.A. (Oak Ridge National Lab., TN (USA)); Cole, D.W. (Washington Univ., Seattle, WA (USA)); Lovett, G.M. (Cary Aboretum, Millbrook, NY (US)); Mitchell, M. (State Univ. of New York, Syracuse, NY (USA)); Ragsdale, L.H. (Emory Univ., Atlanta, GA (USA))

    1987-01-01

    The principal objective of the Integrated Forest Study on Effects of Atmospheric Deposition is to determine the effects of atmospheric deposition at sulfur and nitrogen on forest nutrient cycling. The study integrates a field monitoring component, involving quantification of atmospheric deposition and nutrient cycling in a variety of forest sites, and experimental research, including laboratory and field studies to investigate selected atmospheric and soil processes in great detail. The research is being conducted at forested sites in the northwestern, northeastern, and southeastern United States and in Norway. The sites selected for this study represent a range of conditions in climate, air quality, soils, and vegetation, which will facilitate testing hypotheses about the effects of atmospheric sulfur and nitrogen deposition on forest nutrient cycles. Preliminary results show a wide range in atmospheric sulfur and nitrogen deposition and in ecosystem responses to such deposition, some of which are consistent with previous predictions.

  10. Characterization and Optimization of Mechanical Properties of ABS Parts Manufactured by the Fused Deposition Modelling Process

    Directory of Open Access Journals (Sweden)

    Godfrey C. Onwubolu

    2014-01-01

    Full Text Available While fused deposition modelling (FDM is one of the most used additive manufacturing (AM techniques today due to its ability to manufacture very complex geometries, the major research issues have been to balance ability to produce aesthetically appealing looking products with functionality. In this study, five important process parameters such as layer thickness, part orientation, raster angle, raster width, and air gap have been considered to study their effects on tensile strength of test specimen, using design of experiment (DOE. Using group method of data handling (GMDH, mathematical models relating the response with the process parameters have been developed. Using differential evolution (DE, optimal process parameters have been found to achieve good strength simultaneously for the response. The optimization of the mathematical model realized results in maximized tensile strength. Consequently, the additive manufacturing part produced is improved by optimizing the process parameters. The predicted models obtained show good correlation with the measured values and can be used to generalize prediction for process conditions outside the current study. Results obtained are very promising and hence the approach presented in this paper has practical applications for design and manufacture of parts using additive manufacturing technologies.

  11. Comparison of methods for evaluation of aerosol deposition in the model of human lungs

    Directory of Open Access Journals (Sweden)

    Belka Miloslav

    2014-03-01

    Full Text Available It seems to be very convenient to receive a medicine by inhalation instead of injection. Unfortunately transport of particles and targeted delivery of a drug in human respiratory airways is very complicated task. Therefore we carried out experiments and tested different methods for evaluation of particle deposition in a model of human lungs. The model included respiratory airways from oral cavity to 7th generation of branching. Particles were dispersed by TSI Small-scale Powder Disperser 3433 and delivered to the model. The model was disassembled into segments after the deposition of the particles and local deposition was measured. Two methods were used to analyse the samples, fluorescence spectroscopy and optical microscopy. The first method was based on measuring the intensity of luminescence, which represented the particle deposition. The second method used the optical microscope with phase-contrast objective. A dispersion of isopropanol and particles was filtrated using a vacuum filtration unit, a filter was placed on glass slide and made transparent. The particles on the filter were counted manually and the deposition was calculated afterwards. The results of the methods were compared and both methods proved to be useful.

  12. Application of Physiographic Soil Erosion–Deposition Model in ...

    Indian Academy of Sciences (India)

    69

    2. Ching-Nuo Chen. 3. International Master Program in Soil and Water Engineering, National Pingtung ... technique because of the lack of suitable dam sites, high cost of dam construction, and strict. 29 environmental .... Ziegler et al. 76. (2001) successfully applied the KINEOS2 model to simulate field and road rainfall in. 77.

  13. Application of Physiographic Soil Erosion–Deposition Model in ...

    Indian Academy of Sciences (India)

    69

    University of Science and Technology, Pingtung 912, Taiwan;. 5. Correspondence:; Tel.: (ext .... In recent years, several numerical models considering rainfall runoff and sediment. 75 transport to simulate soil .... cells or river cells. The. 116 physiographic and hydrological data of each cell were obtained through GIS analysis.

  14. Magmatic sulfide-rich nickel-copper deposits related to picrite and (or) tholeiitic basalt dike-sill complexes-A preliminary deposit model

    Science.gov (United States)

    Schulz, Klaus J.; Chandler, Val W.; Nicholson, Suzanne W.; Piatak, Nadine M.; Seal, Robert R.; Woodruff, Laurel G.; Zientek, Michael L.

    2010-01-01

    Magmatic sulfide deposits containing nickel (Ni) and copper (Cu), with or without (?) platinum-group elements (PGEs), account for approximately 60 percent of the world's Ni production and are active exploration targets in the United States and elsewhere. On the basis of their principal metal production, magmatic sulfide deposits in mafic rocks can be divided into two major types: those that are sulfide-rich, typically with 10 to 90 percent sulfide minerals, and have economic value primarily because of their Ni and Cu contents; and those that are sulfide-poor, typically with 0.5 to 5 percent sulfide minerals, and are exploited principally for PGE. Because the purpose of this deposit model is to facilitate the assessment for undiscovered, potentially economic magmatic Ni-Cu?PGE sulfide deposits in the United States, it addresses only those deposits of economic significance that are likely to occur in the United States on the basis of known geology. Thus, this model focuses on deposits hosted by small- to medium-sized mafic and (or) ultramafic dikes and sills that are related to picrite and tholeiitic basalt magmatic systems generally emplaced in continental settings as a component of large igneous provinces (LIPs). World-class examples (those containing greater than 1 million tons Ni) of this deposit type include deposits at Noril'sk-Talnakh (Russia), Jinchuan (China), Pechenga (Russia), Voisey's Bay (Canada), and Kabanga (Tanzania). In the United States, this deposit type is represented by the Eagle deposit in northern Michigan, currently under development by Kennecott Minerals.

  15. Development Of Advanced Sandwich Core Topologies Using Fused Deposition Modeling And Electroforming Processes

    Science.gov (United States)

    Storck, Steven M.

    New weight efficient materials are needed to enhance the performance of vehicle systems allowing increased speed, maneuverability and fuel economy. This work leveraged a multi-length-scale composite approach combined with hybrid material methodology to create new state-of-the-art additive manufactured sandwich core material. The goal of the research was to generate a new material to expands material space for strength versus density. Fused-Deposition-Modeling (FDM) was used to remove geometric manufacturing constraints, and electrodepositing was used to generate a high specific-strength, bio-inspired hybrid material. Microtension samples (3mm x 1mm with 250mum x 250mum gage) were used to investigate the electrodeposited coatings in the transverse (TD) and growth (GD) directions. Three bath chemistries were tested: copper, traditional nickel sulfamate (TNS) nickel, and nickel deposited with a platinum anode (NDPA). NDPA shows tensile strength exceeding 1600 MPa, significantly beyond the literature reported values of 60MPa. This strengthening was linked to grain size refinement into the sub-30nm range, in addition to grain texture refinement resulting in only 17% of the slip systems for nickel being active. Anisotropy was observed in nickel deposits, which was linked to texture evolution inside of the coating. Microsample testing guided the selection of 15mum layer of copper deposition followed by a 250 mum NDPA layer. Classical formulas for structural collapse were used to guide an experimental parametric study to establish a weight/volume efficient strut topology. Length, diameter and thickness were all investigated to determine the optimal column topology. The most optimal topology exists when Eulerian buckling, shell micro buckling and yielding failure modes all exist in a single geometric topology. Three macro-scale sandwich topologies (pyramidal, tetrahedral, and strut-reinforced-tetrahedral (SRT) were investigated with respect to strength-per-unit-weight. The

  16. Comparative studies of spray pyrolysis deposited copper sulfide ...

    Indian Academy of Sciences (India)

    Abstract. CuxS thin films with different Cu to S molar ratios (0·33 and 0·43) have been deposited by spray pyro- lysis method on glass and FTO coated glass substrates using an aqueous solution of copper (II) acetate and thiourea at a substrate temperature of 285◦C. The structural, surface morphological, optical and ...

  17. Comparative studies of spray pyrolysis deposited copper sulfide ...

    Indian Academy of Sciences (India)

    CuS thin films with different Cu to S molar ratios (0.33 and 0.43) have been deposited by spray pyrolysis method on glass and FTO coated glass substrates using an aqueous solution of copper (II) acetate and thiourea at a substrate temperature of 285°C. The structural, surface morphological, optical and electrical ...

  18. New simple deposition model based on reassessment of global fallout data 1954 - 1976

    Energy Technology Data Exchange (ETDEWEB)

    Palsson, S.E. [Icelandic Radiation Safety Authority, Reykjavik (Iceland); Bergan, T.D. [Directorate for Civil Protection and Emergency Planning, Toensberg (Norway); Howard, B.J. [Centre for Ecology and Hydrology, Lancaster Environment Centre, Lancaster (United Kingdom); Ikaeheimonen, T.K. [STUK - Radiation and Nuclear Safety Authority, Helsinki (Finland); Isaksson, M. [Univ. of Gothenburg. Dept. of Radiation Physics, Institute of Clinical Sciences, Sahlgren Academy, Gothenburg (Sweden); Nielsen, Sven P. [Technical Univ. of Denmark. DTU Nutech, Roskilde (Denmark); Paatero, J. [Finnish Meteorological Institute. Observation Services, Helsinki (Finland)

    2012-12-15

    Atmospheric testing of nuclear weapons began in 1945 and largely ceased in 1963. This testing is the major cause of distribution of man-made radionuclides over the globe and constitutes a background that needs to be considered when effects of other sources are estimated. The main radionuclides of long term (after the first months) concern are generally assumed to be {sup 137}Cs and {sup 90}Sr. It has been known for a long time that the deposition density of {sup 137}Cs and {sup 90}Sr is approximately proportional to the amount of precipitation. But the use of this proportional relationship raised some questions such as (a) over how large area can it be assumed that the concentration in precipitation is the same at any given time; (b) how does this agree with the observed latitude dependency of deposition density and (c) are the any other parameters that could be of use in a simple model describing global fallout? These issues were amongst those taken up in the NKS-B EcoDoses activity. The preliminary results for {sup 137}Cs and {sup 90}Sr showed for each that the measured concentration had been similar at many European and N-American sites at any given time and that the change with time had been similar. These finding were followed up in a more thorough study in this (DepEstimates) activity. Global data (including the US EML and UK AERE data sets) from 1954 - 1976 for {sup 90}Sr and {sup 137}Cs were analysed testing how well different potential explanatory variables could describe the deposition density. The best fit was obtained by not assuming the traditional proportional relationship, but instead a non-linear power function. The predictions obtained using this new model may not be significantly different from those obtained using the traditional model, when using a limited data set such as from one country as a test in this report showed. But for larger data sets and understanding of underlying processes the new model should be an improvement. (Author)

  19. Depositional Model for a Beaver Pond Complex in a Piedmont Stream Valley

    Science.gov (United States)

    Rachide, S. P.; Diemer, J. A.

    2016-12-01

    The North American beaver (Castor canadensis) often construct closely-spaced ponds on suitable sections of streams. Over time avulsive processes form an intricate network of shallow anabranching streams that connect a multitude of ponds, referred to here as a beaver pond complex (BPC). According to Polvi and Wohl (2012), BPCs evolve through four stages. Their model, resulting from the study of an alpine stream dominated by meltwater, focused on changes in valley planform, increased channel complexity, and the effects of floodplain sediment storage during the growth of a BPC. A revised depositional model for a multi-generation BPC is presented here, based on data collected at Mill Creek, in the Piedmont of North Carolina. The field data, comprising geolocated maps, cores and probes, were collected between March 2011 and October 2014 and were supplemented by 12 aerial images of the field area taken from January 1993 to October 2014. The revised BPC depositional model comprises several stages of development that include initial beaver occupation, followed by an interval of fast-paced pond creation and increasing channel complexity, a stage of slowing growth of the BPC, followed by cycles of dam breaching and repair, and an abandonment phase. An additional stage may include later reoccupation of an abandoned BPC to produce a multi-generation BPC. The areas affected by, and durations of, these stages are likely dictated by several variables including: geologic controls, local climate, hydrologic regime, beaver population size, and resource availability. Rare large precipitation events that led to the breaching of dams were likely the most impactful variable in the evolution of the Mill Creek BPC. Field observations indicate that beaching events affected the Mill Creek BPC more frequently than could be inferred from the 12 aerial images of the site. Therefore, aerial imagery should be used in conjunction with field-based investigations in order to more accurately

  20. New simple deposition model based on reassessment of global fallout data 1954 - 1976

    International Nuclear Information System (INIS)

    Palsson, S.E.; Bergan, T.D.; Howard, B.J.; Ikaeheimonen, T.K.; Isaksson, M.; Nielsen, Sven P.; Paatero, J.

    2012-12-01

    Atmospheric testing of nuclear weapons began in 1945 and largely ceased in 1963. This testing is the major cause of distribution of man-made radionuclides over the globe and constitutes a background that needs to be considered when effects of other sources are estimated. The main radionuclides of long term (after the first months) concern are generally assumed to be 137 Cs and 90 Sr. It has been known for a long time that the deposition density of 137 Cs and 90 Sr is approximately proportional to the amount of precipitation. But the use of this proportional relationship raised some questions such as (a) over how large area can it be assumed that the concentration in precipitation is the same at any given time; (b) how does this agree with the observed latitude dependency of deposition density and (c) are the any other parameters that could be of use in a simple model describing global fallout? These issues were amongst those taken up in the NKS-B EcoDoses activity. The preliminary results for 137 Cs and 90 Sr showed for each that the measured concentration had been similar at many European and N-American sites at any given time and that the change with time had been similar. These finding were followed up in a more thorough study in this (DepEstimates) activity. Global data (including the US EML and UK AERE data sets) from 1954 - 1976 for 90 Sr and 137 Cs were analysed testing how well different potential explanatory variables could describe the deposition density. The best fit was obtained by not assuming the traditional proportional relationship, but instead a non-linear power function. The predictions obtained using this new model may not be significantly different from those obtained using the traditional model, when using a limited data set such as from one country as a test in this report showed. But for larger data sets and understanding of underlying processes the new model should be an improvement. (Author)

  1. 3D Printing of Intracranial Aneurysms Using Fused Deposition Modeling Offers Highly Accurate Replications.

    Science.gov (United States)

    Frölich, A M J; Spallek, J; Brehmer, L; Buhk, J-H; Krause, D; Fiehler, J; Kemmling, A

    2016-01-01

    As part of a multicenter cooperation (Aneurysm-Like Synthetic bodies for Testing Endovascular devices in 3D Reality) with focus on implementation of additive manufacturing in neuroradiologic practice, we systematically assessed the technical feasibility and accuracy of several additive manufacturing techniques. We evaluated the method of fused deposition modeling for the production of aneurysm models replicating patient-specific anatomy. 3D rotational angiographic data from 10 aneurysms were processed to obtain volumetric models suitable for fused deposition modeling. A hollow aneurysm model with connectors for silicone tubes was fabricated by using acrylonitrile butadiene styrene. Support material was dissolved, and surfaces were finished by using NanoSeal. The resulting models were filled with iodinated contrast media. 3D rotational angiography of the models was acquired, and aneurysm geometry was compared with the original patient data. Reproduction of hollow aneurysm models was technically feasible in 8 of 10 cases, with aneurysm sizes ranging from 41 to 2928 mm(3) (aneurysm diameter, 3-19 mm). A high level of anatomic accuracy was observed, with a mean Dice index of 93.6% ± 2.4%. Obstructions were encountered in vessel segments of modeling is a promising technique, which allows rapid and precise replication of cerebral aneurysms. The porosity of the models can be overcome by surface finishing. Models produced with fused deposition modeling may serve as educational and research tools and could be used to individualize treatment planning. © 2016 by American Journal of Neuroradiology.

  2. CuFeO2 formation using fused deposition modeling 3D printing and sintering technique

    Science.gov (United States)

    Salea, A.; Dasaesamoh, A.; Prathumwan, R.; Kongkaew, T.; Subannajui, K.

    2017-09-01

    CuFeO2 is a metal oxide mineral material which is called delafossite. It can potentially be used as a chemical catalyst, and gas sensing material. There are methods to fabricate CuFeO2 such as chemical synthesis, sintering, sputtering, and chemical vapor deposition. In our work, CuFeO2 is prepared by Fused Deposition Modeling (FDM) 3D printing. The composite filament which composed of Cu and Fe elements is printed in three dimensions, and then sintered and annealed at high temperature to obtain CuFeO2. Suitable polymer blend and maximum percent volume of metal powder are studied. When percent volume of metal powder is increased, melt flow rate of polymer blend is also increased. The most suitable printing condition is reported and the properties of CuFeO2 are observed by Scanning Electron Microscopy, and Dynamic Scanning Calorimeter, X-ray diffraction. As a new method to produce semiconductor, this technique has a potential to allow any scientist or students to design and print a catalyst or sensing material by the most conventional 3D printing machine which is commonly used around the world.

  3. Development of a Guinea Pig Lung Deposition Model

    Science.gov (United States)

    2016-01-01

    lung airways are not feasible due to the large number of airways, complexity of the lung geometry, and lack of data on pleural pressure distribution...modeling each airway as a cylindrical tube and the lung as a dichotomous branching network of airways, representative, typical-path, dichotomous and...pressure between the atmosphere and pleural pressure in the lung cavity during inhalation. While inhalation is initiated by the expansion of the lung

  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 I. Base case model results.

    Science.gov (United States)

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

    2015-11-01

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

  5. Distribution and Orientation of Carbon Fibers in Polylactic Acid Parts Produced by Fused Deposition Modeling

    DEFF Research Database (Denmark)

    Hofstätter, Thomas; W. Gutmann, Ingomar; Koch, Thomas

    2016-01-01

    The aim of this paper is the understanding of the fiber orientation by investigations in respect to the inner configuration of a polylactic acid matrix reinforced with short carbon fibers after a fused deposition modeling extrusion process. The final parts were analyzed by X-ray, tomography......, and magnetic resonance imaging allowing a resolved orientation of the fibers and distribution within the part. The research contributes to the understanding of the fiber orientation and fiber reinforcement of fused deposition modeling parts in additive manufacturing....

  6. Energy deposition model based on electron scattering cross section data from water molecules

    Energy Technology Data Exchange (ETDEWEB)

    Munoz, A; Oiler, J C [Centra de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Avenida Complutense 22, 28040 Madrid (Spain); Blanco, F [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid, Avenida Complutense s.n., 28040 Madrid (Spain); Gorfinkiel, J D [Department of Physiscs and Astronomy, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Limao-Vieira, P [Departamento de Fisica, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Maira-Vidal, A; Borge, M J G; Tengblad, O [Instituto de Estructura de la Materia, Consejo Superior de Investigaciones Cientificas (CSIC), Serrano 113-bis, 28006 Madrid, Spam (Spain); Huerga, C; Tellez, M [Hospital Universitario La Paz, paseo de la Castellana 261, 28046 Madrid (Spain); Garcia, G [Instituto de Matematicas y Fisica Fundamental, Consejo Superior de Investigaciones CientifIcas (CSIC), Serrano 113-bis, 28006 Madrid (Spain)], E-mail: g.garcia@imaff.cfmac.csic.es

    2008-10-01

    A complete set of electrons scattering cross sections by water molecules over a broad energy range, from the me V to the Me V ranges, is presented in this study. These data have been obtained by combining experiments and calculations and cover most relevant processes, both elastic and inelastic, which can take place in the considered energy range. A new Monte Carlo simulation programme has been developed using as input parameter these cross sectional data as well as experimental energy loss spectra. The simulation procedure has been applied to obtain electron tracks and energy deposition plots in water when irradiated by a Ru-106 plaque as those used for brachytherapy of ocular tumours. Finally, the low energy electron tracks provided by the present model have been compared with those obtained with other codes available in the literature.

  7. Evaluating Ammonia Deposition Rates for Deciduous Forest using Measurements and Modelling

    DEFF Research Database (Denmark)

    Hansen, Kristina; Geels, Camilla; Hertel, Ole

    -agricultural areas (Skjøth et al. 2011, ACPD). New atmospheric NH3 flux measurements for Lille Bøgeskov have been conducted throughout 2011 and these data are presented and discussed in relation to the 2010 data of atmospheric NH3. Future studies aim to improve the description of dry deposition of NH3 for vegetative...... atmospheric mean concentrations of NH3 agreed well within the range of 0.56-0.68 g NH3-N m-3, however, observed emission fluxes of up to app. 0.8 g NH3-N m-2 s-1 after leaf fall were not represented by DAMOS because the model system does not consider vegetative and soil NH3 emissions from non...

  8. Investigation of dimensional variation in parts manufactured by fused deposition modeling using Gauge Repeatability and Reproducibility

    Science.gov (United States)

    Mohamed, Omar Ahmed; Hasan Masood, Syed; Lal Bhowmik, Jahar

    2018-02-01

    In the additive manufacturing (AM) market, the question is raised by industry and AM users on how reproducible and repeatable the fused deposition modeling (FDM) process is in providing good dimensional accuracy. This paper aims to investigate and evaluate the repeatability and reproducibility of the FDM process through a systematic approach to answer this frequently asked question. A case study based on the statistical gage repeatability and reproducibility (gage R&R) technique is proposed to investigate the dimensional variations in the printed parts of the FDM process. After running the simulation and analysis of the data, the FDM process capability is evaluated, which would help the industry for better understanding the performance of FDM technology.

  9. Study of Polymer Crystallization by Physical Vapor Deposition

    Science.gov (United States)

    Jeong, Hyuncheol

    When a polymer is confined under the submicron length scale, confinement size and interfaces can significantly impact the crystallization kinetics and resulting morphology. The ability to tune the morphology of confined polymer systems is of critical importance for the development of high-performance polymer microelectronics. The wisdom from the research on confined crystallization suggests that it would be beneficial to have a processing route in which the crystallization of polymers is driven by interface and temperature effects at a nanometer-scale confinement. In practice, for atomic and small-molecular systems, physical vapor deposition (PVD) has been recognized as the most successful processing route for the precise control of the film structure at surface utilizing confinement effects. While standard PVD technologies are not generally applicable to the deposition of the chemically fragile macromolecules, the development of matrix-assisted pulsed laser evaporation (MAPLE) now enables the non-destructive PVD of high-molecular weight polymers. In this thesis work, we investigated the use of MAPLE for the precise control of the crystallization of polymer films at a molecular level. We also sought to decipher the rules governing the crystallization of confined polymers, by using MAPLE as a tool to form confined polymer systems onto substrates with a controlled temperature. We first explored the early stages of film growth and crystallization of poly(ethylene oxide) (PEO) at the substrate surface formed by MAPLE. The unique mechanism of film formation in MAPLE, the deposition of submicron-sized polymer droplets, allowed for the manifestation of confinement and substrate effects in the crystallization of MAPLE-deposited PEO. Furthermore, we also focused on the property of the amorphous PEO film formed by MAPLE, showing the dependence of polymer crystallization kinetics on the thermal history of the amorphous phase. Lastly, we probed how MAPLE processing affected

  10. Acid Deposition Simulations for Alberta, Saskatchewan, and the Canadian Oil Sands, using the Global Environmental Multiscale - Modelling Air-quality and CHemistry (GEM-MACH) System

    Science.gov (United States)

    Makar, Paul; Akingunola, Ayodeji; Moran, Michael; Wong, Isaac; Aherne, Julian; Hayden, Katherine; Li, Shao-Meng; Zhang, Junhua; Baratzedah, Pegha; Pabla, Balbir; Cheung, Philip; Cole, Amanda; Kirk, Jane; Scott, Ken

    2017-04-01

    carried out for this period, in order to study the effect of the use of successively more advanced emissions data on model predictions of deposition, as well as the relative impact of employing 12 versus 2 bins for the model's aerosol size distribution. These model scenarios were compared to aircraft-based estimates of SO2 and particulate sulphate deposition.

  11. A study of U-Pb isotopic evolutionary system in Chanziping uranium deposit

    International Nuclear Information System (INIS)

    Xu Weichang; Huang Shijie; Xia Yuliang.

    1988-01-01

    Chanziping uranium deposit occurred in the black siliceous slate of Lower cambrian. The uranium mineralization was controlled by both interstratified fault belt and the ore-bearing beds. Based on the study of the U-Pb isotopic system of the various rocks, ores and minerals in the ore-bearing beds, the authors find out the obvious disequilibrium of U-Pb isotopic composition in most rock samples which indicates the loss of uranium form the ore-bearing beds and surrounding granite. Its counting loss ranges from 30 to 80%. The age of rich ores of the U-Pb concordance diagram and the U-Pb three stage model are t 1 = 523 ± 19M. Y. , t 2 = 22 ± 2 M.Y.. The isochronal ages for pitchblend are 75 ± 4 M.Y., 43 ± 7 M.Y., and for rock is 416 M.y.. These data shows that the uranium in ore-bearing beds was mainly derived from the ore-bearing beds itself and partly from the surrounding granite. The ore deposit can be considered to be of stratabound uranium deposit of sedimentation and late transformation type

  12. Melt flow behaviour of poly-epsilon-caprolactone in fused deposition modelling.

    Science.gov (United States)

    Ramanath, H S; Chua, C K; Leong, K F; Shah, K D

    2008-07-01

    Fused deposition modelling (FDM) is an extrusion based Rapid prototyping (RP) technique which can be used to fabricate tissue engineering scaffolds. The present work focuses on the study of the melt flow behaviour (MFB) of Poly-epsilon-caprolactone (PCL) as a representative biomaterial, on the FDM. The MFB significantly affects the quality of the scaffold which depends not only on the pressure gradient, its velocity, and the temperature gradients but also physical properties like the melt temperature and rheology. The MFB is studied using two methods: mathematical modelling and finite element analysis (FEA) using Ansys(R). The MFB is studied using accurate channel geometry by varying filament velocity at the entry and by varying nozzle diameters and angles at the exit. The comparative results of both mathematical modelling and FEA suggest that the pressure drop and the velocities of the melt flow depend on the flow channel parameters. One inference of particular interest is the temperature gradient of the PCL melt, which shows that it liquefies within 35% of the channel length. These results are invaluable to better understand the MFB of biomaterials that affects the quality of the scaffold built via FDM and can also be used to predict the MFB of other biomaterials.

  13. New models of droplet deposition and entrainment for prediction of CHF in cylindrical rod bundles

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Haibin, E-mail: hb-zhang@xjtu.edu.cn [School of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an 710049 (China); Department of Chemical Engineering, Imperial College, London SW7 2BY (United Kingdom); Hewitt, G.F. [Department of Chemical Engineering, Imperial College, London SW7 2BY (United Kingdom)

    2016-08-15

    Highlights: • New models of droplet deposition and entrainment in rod bundles is developed. • A new phenomenological model to predict the CHF in rod bundles is described. • The present model is well able to predict CHF in rod bundles. - Abstract: In this paper, we present a new set of model of droplet deposition and entrainment in cylindrical rod bundles based on the previously proposed model for annuli (effectively a “one-rod” bundle) (2016a). These models make it possible to evaluate the differences of the rates of droplet deposition and entrainment for the respective rods and for the outer tube by taking into account the geometrical characteristics of the rod bundles. Using these models, a phenomenological model to predict the CHF (critical heat flux) for upward annular flow in vertical rod bundles is described. The performance of the model is tested against the experimental data of Becker et al. (1964) for CHF in 3-rod and 7-rod bundles. These data include tests in which only the rods were heated and data for simultaneous uniform and non-uniform heating of the rods and the outer tube. It was shown that the predicted CHFs by the present model agree well with the experimental data and with the experimental observation that dryout occurred first on the outer rods in 7-rod bundles. It is expected that the methodology used will be generally applicable in the prediction of CHF in rod bundles.

  14. In-vitro evaluation of Polylactic acid (PLA) manufactured by fused deposition modeling.

    Science.gov (United States)

    Wurm, Matthias C; Möst, Tobias; Bergauer, Bastian; Rietzel, Dominik; Neukam, Friedrich Wilhelm; Cifuentes, Sandra C; Wilmowsky, Cornelius von

    2017-01-01

    With additive manufacturing (AM) individual and biocompatible implants can be generated by using suitable materials. The aim of this study was to investigate the biological effects of polylactic acid (PLA) manufactured by Fused Deposition Modeling (FDM) on osteoblasts in vitro according to European Norm / International Organization for Standardization 10,993-5. Human osteoblasts (hFOB 1.19) were seeded onto PLA samples produced by FDM and investigated for cell viability by fluorescence staining after 24 h. Cell proliferation was measured after 1, 3, 7 and 10 days by cell-counting and cell morphology was evaluated by scanning electron microscopy. For control, we used titanium samples and polystyrene (PS). Cell viability showed higher viability on PLA (95,3% ± 2.1%) than in control (91,7% ±2,7%). Cell proliferation was highest in the control group (polystyrene) and higher on PLA samples compared to the titanium samples. Scanning electron microscopy revealed homogenous covering of sample surface with regularly spread cells on PLA as well as on titanium. The manufacturing of PLA discs from polylactic acid using FDM was successful. The in vitro investigation with human fetal osteoblasts showed no cytotoxic effects. Furthermore, FDM does not seem to alter biocompatibility of PLA. Nonetheless osteoblasts showed reduced growth on PLA compared to the polystyrene control within the cell experiments. This could be attributed to surface roughness and possible release of residual monomers. Those influences could be investigated in further studies and thus lead to improvement in the additive manufacturing process. In addition, further research focused on the effect of PLA on bone growth should follow. In summary, PLA processed in Fused Deposition Modelling seems to be an attractive material and method for reconstructive surgery because of their biocompatibility and the possibility to produce individually shaped scaffolds.

  15. Simulation of nitrogen deposition in the North China Plain by the FRAME model

    Directory of Open Access Journals (Sweden)

    Y. Zhang

    2011-11-01

    Full Text Available Simulation of atmospheric nitrogen (N deposition in the North China Plain (NCP at high resolution, 5 × 5 km2, was conducted for the first time by the Fine Resolution Atmospheric Multi-pollutant Exchange (FRAME model. The total N deposition budget was 1481 Gg in this region, with 77 % from reduced N and 23 % from oxidized N, and the annual deposition rate (47 kg N ha−1 was much higher than previously reported values for other parts of the world such as the UK (13 kg N ha−1, Poland (7.3 kg N ha−1 and EU27 (8.6 kg N ha−1. The exported N component (1981 Gg was much higher than the imported N component (584 Gg, suggesting that the NCP is an important net emission source of N pollutants. Contributions of N deposition budgets from the seven provinces in this region were proportional to their area ratios. The calculated spatial distributions of N deposition displayed high rates of reduced N deposition in the south and of oxidized N deposition in the eastern part. The N deposition exceeded an upper limit of 30 kg N ha−1 for natural ecosystems over more than 90 % of the region, resulting in terrestrial ecosystem deterioration, impaired air quality and coastal eutrophication not only in the NCP itself but also in surrounding areas including the Bohai Sea and the Yellow Sea.

  16. A COMPARISON OF THE TENSILE STRENGTH OF PLASTIC PARTS PRODUCED BY A FUSED DEPOSITION MODELING DEVICE

    OpenAIRE

    Juraj Beniak; Peter Križan; Miloš Matúš

    2015-01-01

    Rapid Prototyping systems are nowadays increasingly used in many areas of industry, not only for producing design models but also for producing parts for final use. We need to know the properties of these parts. When we talk about the Fused Deposition Modeling (FDM) technique and FDM devices, there are many possible settings for devices and models which could influence the properties of a final part. In addition, devices based on the same principle may use different operational software for c...

  17. Comparative studies of spray pyrolysis deposited copper sulfide ...

    Indian Academy of Sciences (India)

    Optical measurements showed that all these materials have a relatively high absorption coefficient (∼5 ×. 104–2·3 × 105 cm−1) in the visible ... The deposition of co- pper sulfide thin films was carried out with two Cu to S molar ratios of 1:3 = 0·33 and 1:2·28 = 0·43 at a substrate tem- perature of 285. ◦. C on glass substrate ...

  18. A field study of pollutant deposition in radiation fog

    Energy Technology Data Exchange (ETDEWEB)

    Waldman, J.M.; Jacob, D.J.; Munger, J.W.; Hoffman, M.R.

    1986-04-01

    Deposition during fog episodes can make a significant contribution to the overall flux of pollutants in certain ecosystems. Furthermore, when atmospheric stagnation prevents normal ventilation in a region, fog deposition may become the main route of pollutant removal. Fogs can consequently exert dominant control over pollutant levels in certain atmospheres. The southern San Joaquin Valley (SJV) of California is a region prone to wintertime episodes of atmospheric stagnation. These lead to elevated pollutant concentrations and/or dense, widespread fogs. Major oil-recovery operations plus widespread agricultural and livestock feeding activities are important sources of SO/sub 2/, NO/sub X/ and NH/sub 3/ in the valley. A multifaceted program of field monitoring was conducted in the SJV during the winter 1984-1985, focusing on aspects of pollutant scavenging and removal in the fog-laden atmosphere. Concentrations of major species were measured in gas, dry aerosol and fogwater phases. In addition, depositional fluxes were monitored by surrogate-surface methods. These measurements were employed to directly assess the magnitude of removal enhancement by fog.

  19. Multi-model mean nitrogen and sulfur deposition from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP): evaluation historical and projected changes

    Science.gov (United States)

    Lamarque, J.-F.; Dentener, F.; McConnell, J.; Ro, C.-U.; Shaw, M.; Vet, R.; Bergmann, D.; Cameron-Smith, P.; Doherty, R.; Faluvegi, G.; Ghan, S. J.; Josse, B.; Lee, Y. H.; MacKenzie, I. A.; Plummer, D.; Shindell, D. T.; Stevenson, D. S.; Strode, S.; Zeng, G.

    2013-03-01

    We present multi-model global datasets of nitrogen and sulfate deposition covering time periods from 1850 to 2100, calculated within the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP). The computed deposition fluxes are compared to surface wet deposition and ice-core measurements. We use a new dataset of wet deposition for 2000-2002 based on critical assessment of the quality of existing regional network data. We show that for present-day (year 2000 ACCMIP time-slice), the ACCMIP results perform similarly to previously published multi-model assessments. For this time slice, we find a multi-model mean deposition of 50 Tg(N) yr-1 from nitrogen oxide emissions, 60 Tg(N) yr-1 from ammonia emissions, and 83 Tg(S) yr-1 from sulfur emissions. The analysis of changes between 1980 and 2000 indicates significant differences between model and measurements over the United States but less so over Europe. This difference points towards misrepresentation of 1980 NH3 emissions over North America. Based on ice-core records, the 1850 deposition fluxes agree well with Greenland ice cores but the change between 1850 and 2000 seems to be overestimated in the Northern Hemisphere for both nitrogen and sulfur species. Using the Representative Concentration Pathways to define the projected climate and atmospheric chemistry related emissions and concentrations, we find large regional nitrogen deposition increases in 2100 in Latin America, Africa and parts of Asia under some of the scenarios considered. Increases in South Asia are especially large, and are seen in all scenarios, with 2100 values more than double 2000 in some scenarios and reaching > 1300 mg(N) m-2 yr-1 averaged over regional to continental scale regions in RCP 2.6 and 8.5, ~30-50 % larger than the values in any region currently (2000). The new ACCMIP deposition dataset provides novel, consistent and evaluated global gridded deposition fields for use in a wide range of climate and ecological studies.

  20. Atmospheric Breakup and Energy Deposition Modeling for Asteroid Impact Risk Assessmen

    Science.gov (United States)

    Wheeler, L.; Mathias, D.

    2016-12-01

    The Asteroid Threat Assessment Project (ATAP) team at NASA Ames Research Center is developing physics-based models to assess the risk posed by potential asteroid strikes on Earth. As part of this effort, an analytic asteroid fragmentation model has been developed to model the atmospheric energy deposition of asteroids with a range of compositional properties and entry conditions. The resulting energy deposition profiles are used to estimate airburst altitudes and blast overpressure damage on the ground. The model approach combines successive fragmentation of larger independent pieces with the release of aggregate clouds of debris. A wide range of potential breakup behaviors can be assessed by varying the number and masses of fragments produced, the fraction of mass released as debris clouds, and the size-strength scaling used to increase the durability of smaller fragments. The initial asteroid body can also be seeded with a distribution of independent fragment sizes and remaining debris mass to represent a variety of structural types, from rubble piles to coherent monoliths. The model is able to reproduce key energy deposition features, such as multiple flares, high-altitude regolith blow-off, or initial disruption of loosely bound conglomerations followed by more energetic breakup of the constituent boulders. These capabilities provide a means to investigate sensitivities of energy deposition to potential variations in asteroid structure, while also maintaining a level of fidelity appropriate for the large numbers of cases needed for statistical risk assessment.

  1. A study of the sand and gravel deposits around the permanent site ...

    African Journals Online (AJOL)

    A geophysical investigation of the sand and gravel deposits at the Federal University of Technology Owerri was carried out using the vertical electrical sounding (VES) approach. The aim of the study was to determine the occurrences and depths of sand and gravel deposits at the study area. This was done using the ...

  2. Modelling of local carbon deposition on rough test limiter exposed to the edge plasma of TEXTOR

    International Nuclear Information System (INIS)

    Dai Shuyu; Sun Jizhong; Wang Dezhen; Kirschner, A.; Matveev, D.; Borodin, D.; Bjoerkas, C.

    2013-01-01

    A Monte-Carlo code called SURO has been developed to study the influence of surface roughness on the impurity deposition characteristic in fusion experiments. SURO uses the test particle approach to describe the impact of background plasma and the deposition of impurity particles on a sinusoidal surface. The local impact angle and dynamic change of surface roughness as well as surface concentrations of different species due to erosion and deposition are taken into account. Coupled with 3D Monte-Carlo code ERO, SURO was used to study the impact of surface roughness on 13 C deposition in 13 CH 4 injection experiments in TEXTOR. The simulations showed that the amount of net deposited 13 C species increases with surface roughness. Parameter studies with varying 12 C and 13 C fluxes were performed to gain insight into impurity deposition characteristic on the rough surface. Calculations of the exposure time needed for surface smoothing for TEXTOR and ITER were also carried out for different scenarios. (author)

  3. Vacuum fused deposition modelling system to improve tensile ...

    African Journals Online (AJOL)

    This paper presents a possible solution to this problem by incorporating vacuum technology in FDM system to improve tensile strength of 3D printed specimens. In this study, a desktop FDM machine was placed and operated inside a low pressure vacuum chamber. The results obtained show an improvement of 12.83 % of ...

  4. A diagnostic evaluation of modeled mercury wet depositions in Europe using atmospheric speciated high-resolution observations.

    Science.gov (United States)

    Bieser, J; De Simone, F; Gencarelli, C; Geyer, B; Hedgecock, I; Matthias, V; Travnikov, O; Weigelt, A

    2014-01-01

    This study is part of the Global Mercury Observation System (GMOS), a European FP7 project dedicated to the improvement and validation of mercury models to assist in establishing a global monitoring network and to support political decisions. One key question about the global mercury cycle is the efficiency of its removal out of the atmosphere into other environmental compartments. So far, the evaluation of modeled wet deposition of mercury was difficult because of a lack of long-term measurements of oxidized and elemental mercury. The oxidized mercury species gaseous oxidized mercury (GOM) and particle-bound mercury (PBM) which are found in the atmosphere in typical concentrations of a few to a few tens pg/m(3) are the relevant components for the wet deposition of mercury. In this study, the first European long-term dataset of speciated mercury taken at Waldhof/Germany was used to evaluate deposition fields modeled with the chemistry transport model (CTM) Community Multiscale Air Quality (CMAQ) and to analyze the influence of the governing parameters. The influence of the parameters precipitation and atmospheric concentration was evaluated using different input datasets for a variety of CMAQ simulations for the year 2009. It was found that on the basis of daily and weekly measurement data, the bias of modeled depositions could be explained by the bias of precipitation fields and atmospheric concentrations of GOM and PBM. A correction of the modeled wet deposition using observed daily precipitation increased the correlation, on average, from 0.17 to 0.78. An additional correction based on the daily average GOM and PBM concentration lead to a 50% decrease of the model error for all CMAQ scenarios. Monthly deposition measurements were found to have a too low temporal resolution to adequately analyze model deficiencies in wet deposition processes due to the nonlinear nature of the scavenging process. Moreover, the general overestimation of atmospheric GOM by the CTM

  5. A chemical and fluid dynamic study of the chemical vapor deposition of aluminum nitride in a vertical reactor

    Science.gov (United States)

    Bather, Wayne Anthony

    The metalorganic chemical vapor deposition (MOCVD) growth of compound semiconductors has become important in producing many high performance electronic and optoelectronic devices from the wide bandgaps III-V nitrides, for example, aluminum nitride (AlN). A systematic theoretical and experimental investigation of the chemistry and mass transport process in a MOCVD system can yield predictive models of the deposition process. The chemistries and fluid dynamics of the MOCVD growth of AlN in a vertical reactor is analyzed and characterized in order to parameterize and model the deposition process. A Fourier Transform Infrared (FTIR) spectroscopic study of the predeposition reactions between trimethylaluminum (TMAl) and ammonia (NHsb3) is carried out in a static gas cell to examine the primary homogeneous gas phase reactions, pyrolysis of the reactants, and adduct formation, possibly accompanied by elimination reactions. A series of reactions, based on laboratory studies and literature review, is then proposed to model the deposition process. All pertinent kinetic, thermochemical, and transport properties were obtained. Utilizing a mass transport model, we performed computational fluid dynamics calculations using the FLUENT software package. We determined temperature, velocity, and concentration profiles, along with deposition rates inside the experimental vertical CVD reactor in the Howard University Material Science Research Center of Excellence. Experimental deposition rate data were found to be in good agreement with those predicted from the simulations, thus validating the proposed model. The control of the homogeneous gas phase reaction leading to the formation and subsequent decomposition of the adduct is critical to the formation of device-grade AlN films. Many basic processes occurring during MOCVD of AlN are still not completely understood, and none of the detailed surface reaction mechanisms are known.

  6. AFM investigation and optical band gap study of chemically deposited PbS thin films

    Science.gov (United States)

    Zaman, S.; Mansoor, M.; Abubakar; Asim, M. M.

    2016-08-01

    The interest into deposition of nanocrystalline PbS thin films, the potential of designing and tailoring both the topographical features and the band gap energy (Eg) by controlling growth parameters, has significant technological importance. Nanocrystalline thin films of lead sulfide were grown onto glass substrates by chemical bath deposition (CBD) method. The experiments were carried out by varying deposition temperature. We report on the modification of structural and optical properties as a function of deposition temperature. The morphological changes of the films were analyzed by using SEM and AFM. AFM was also used to calculate average roughness of the films. XRD spectra indicated preferred growth of cubic phase of PbS films in (200) direction with increasing deposition time. Optical properties have been studied by UV-Spectrophotometer. From the diffused reflectance spectra we have calculated the optical Eg shift from 0.649-0.636 eV with increasing deposition time.

  7. Acid deposition modelling and the interpretation of the United Kingdom secondary precipitation network data

    Science.gov (United States)

    Metcalfe, S. E.; Atkins, D. H. F.; Derwent, R. G.

    Acid deposition modelling calculations have been compared against the data obtained during the first year's operation of the United Kingdom Secondary Precipitation Network. The model adopted employed a single level trajectory approach to describe the coupled atmospheric chemistry and deposition of SO x NO y and NH x species. For the precipitation sulphate concentrations, the model results over the 47 network sites correlated well with the observations. When corrections were applied within the model calculations for background deposition and for dry deposition into the bulk collector, then the model results overestimated the precipitation sulphate observations by about 27%. For the precipitation nitrate concentrations, again the model results correlated well with the observations. Over the whole network, the model underestimated the observations by about 6% and no significant background correction was required for background sources. For the precipitation ammonium concentrations, good agreement with the observations could only be obtained if an additional ammonia source over and above that from animal manure was included in the model. One possibility investigated was exhalation from agricultural soils with an emission rate of 50-100 kg NH x ha -1 a -1. The model was able to reproduce the main features of the distributions of NO 2 and NH 3 in terms of gradients across the U.K. and in the location of the respective maxima. However, in both cases, severe underestimation by the model was apparent. The source of this underestimation was found to involve the assumption of complete vertical mixing in the model and the neglect of nocturnal stable layers.

  8. Uranium metallogenic model related to CO2 and hydrocarbon in granite type uranium deposits

    International Nuclear Information System (INIS)

    Ou Guangxi; Chen Anfu; Cui Jianyong; Xu Yinhuan; Wang Chunhua; Xu Yan

    2001-01-01

    The report is concerned with the inseparable connections between the uranium migration, enrichment rule and the geochemical characteristics of CO 2 and hydrocarbon gas, as well as the relations between the deposit locations and the gas abnormal distribution in rocky body, which are based on the analysis of some data and phenomena in 11 typical deposits in 2 granite type uranium ore fields, including the observations of 250 rocky fluid inclusion sections and the analyzed data of which 2470 are in gas composition, 200 in uranium content, 50 in thermometry. All the conclusions are drawn from different angles for the first time and this new exploration and advancement fills up the blank of gas geochemistry study in uranium deposits or other metal deposits

  9. Study of the deposition process of vinpocetine on the surface of porous silicon

    Science.gov (United States)

    Lenshin, A. S.; Polkovnikova, Yu. A.; Seredin, P. V.

    Currently the most prospective way in pharmacotherapy is the obtaining of nanoparticles involving pharmaceutical substances. Application of porous inorganic materials on the basis of silicon is among the main features in solving of this problem. The present work is concerned with the problem of the deposition of pharmaceutical drug with nootropic activity - vinpocetine - into porous silicon. Silicon nanoparticles were obtained by electrochemical anodic etching of Si plates. The process of vinpocetine deposition was studied in dependence of the deposition time. As a result of the investigations it was found that infrared transmission spectra of porous silicon with the deposited vinpocetine revealed the absorption bands characteristic of vinpocetine substance.

  10. Kinetic Monte-Carlo modeling of hydrogen retention and re-emission from Tore Supra deposits

    International Nuclear Information System (INIS)

    Rai, A.; Schneider, R.; Warrier, M.; Roubin, P.; Martin, C.; Richou, M.

    2009-01-01

    A multi-scale model has been developed to study the reactive-diffusive transport of hydrogen in porous graphite [A. Rai, R. Schneider, M. Warrier, J. Nucl. Mater. (submitted for publication). http://dx.doi.org/10.1016/j.jnucmat.2007.08.013.]. The deposits found on the leading edge of the neutralizer of Tore Supra are multi-scale in nature, consisting of micropores with typical size lower than 2 nm (∼11%), mesopores (∼5%) and macropores with a typical size more than 50 nm [C. Martin, M. Richou, W. Sakaily, B. Pegourie, C. Brosset, P. Roubin, J. Nucl. Mater. 363-365 (2007) 1251]. Kinetic Monte-Carlo (KMC) has been used to study the hydrogen transport at meso-scales. Recombination rate and the diffusion coefficient calculated at the meso-scale was used as an input to scale up and analyze the hydrogen transport at macro-scale. A combination of KMC and MCD (Monte-Carlo diffusion) method was used at macro-scales. Flux dependence of hydrogen recycling has been studied. The retention and re-emission analysis of the model has been extended to study the chemical erosion process based on the Kueppers-Hopf cycle [M. Wittmann, J. Kueppers, J. Nucl. Mater. 227 (1996) 186].

  11. Considerations on thermic and mechanic processes that appear when 3D printing using ABS fused deposition modelling technology

    Science.gov (United States)

    Amza, Catalin Gheorghe; Niţoi, Dan Florin

    2018-02-01

    3D printers are of recent history, but with an extremely rapid evolution both in technology and hardware involved. At present excellent performances are reached in applications such as 3D printing of various Acrylonitrile butadiene styrene (ABS) plastic parts for house building using Fused Deposition Modelling technology. Nevertheless, the thermic and mechanic processes that appear when manufacturing such plastic components are quite complex. This aspect is very important, especially when one wants to optimize the manufacturing of parts with certain geometrical complexity. The Finite Element Analysis/Modelling (FEA/FEM) is among the few methods that can study the thermic transfer processes and shape modifications that can appear due to non-seamar behavior that takes place when the ABS plastic material is cooling down. The current papers present such an analysis when simulating the deposition of several strings of materials. A thermic analysis is made followed by a study of deformations that appear when the structure cools down.

  12. 3D Hatching : Linear halftoning for dual extrusion fused deposition modeling

    NARCIS (Netherlands)

    Kuipers, Tim; Doubrovski, E.L.; Verlinden, J.C.

    2017-01-01

    This work presents halftoning techniques to manufacture 3D objects with the appearance of full grayscale imagery for Fused Deposition Modeling (FDM) printers. While droplet-based dithering is a common halftoning technique, this is not applicable to FDM printing, since FDM builds up objects by

  13. Modelling the impact of climate change and atmospheric N deposition on French forests biodiversity.

    Science.gov (United States)

    Rizzetto, Simon; Belyazid, Salim; Gégout, Jean-Claude; Nicolas, Manuel; Alard, Didier; Corcket, Emmanuel; Gaudio, Noémie; Sverdrup, Harald; Probst, Anne

    2016-06-01

    A dynamic coupled biogeochemical-ecological model was used to simulate the effects of nitrogen deposition and climate change on plant communities at three forest sites in France. The three sites had different forest covers (sessile oak, Norway spruce and silver fir), three nitrogen loads ranging from relatively low to high, different climatic regions and different soil types. Both the availability of vegetation time series and the environmental niches of the understory species allowed to evaluate the model for predicting the composition of the three plant communities. The calibration of the environmental niches was successful, with a model performance consistently reasonably high throughout the three sites. The model simulations of two climatic and two deposition scenarios showed that climate change may entirely compromise the eventual recovery from eutrophication of the simulated plant communities in response to the reductions in nitrogen deposition. The interplay between climate and deposition was strongly governed by site characteristics and histories in the long term, while forest management remained the main driver of change in the short term. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Comparisons of measured and modelled ozone deposition to forests in northern Europe

    DEFF Research Database (Denmark)

    Touvinen, J. P.; Simpson, D.; Mikkelsen, Teis Nørgaard

    2001-01-01

    The performance of a new dry deposition module, developedfor the European-scale mapping and modelling of ozone flux to vegetation, was tested against micrometeorological ozone and water vapour flux measurements. The measurement data are for twoconiferous (Scots pine in Finland, Norway spruce...

  15. Fused Deposition Modeling 3D Printing for (Bio)analytical Device Fabrication : Procedures, Materials, and Applications

    NARCIS (Netherlands)

    Salentijn, Gert Ij; Oomen, Pieter E; Grajewski, Maciej; Verpoorte, Elisabeth

    2017-01-01

    In this work, the use of fused deposition modeling (FDM) in a (bio)analytical/lab-on-a-chip research laboratory is described. First, the specifications of this 3D printing method that are important for the fabrication of (micro)devices were characterized for a benchtop FDM 3D printer. These include

  16. The APO(*)E3-Leiden mouse as an animal model for basal laminar deposit

    NARCIS (Netherlands)

    Kliffen, M.; Lutgens, E.; Daemen, M. J.; de Muinck, E. D.; Mooy, C. M.; de Jong, P. T.

    2000-01-01

    To investigate the APO(*)E3-Leiden mouse as an animal model for age related maculopathy (ARM) related extracellular deposits. Eyes were obtained from APO(*)E3-Leiden transgenic mice on a high fat/cholesterol (HFC) diet (n=12) or on a normal mouse chow (n=6), for 9 months. As controls, eyes were

  17. The APO(*)E3-Leiden mouse as an animal model for basal laminar deposit

    NARCIS (Netherlands)

    M. Kliffen (Mike); E. Lutgens; M.J. Daemen (Mat); E.D. de Muinck; C.M. Mooy (Cornelia); P.T.V.M. de Jong (Paulus)

    2000-01-01

    textabstractAIM: To investigate the APO(*)E3-Leiden mouse as an animal model for age related maculopathy (ARM) related extracellular deposits. METHODS: Eyes were obtained from APO(*)E3-Leiden transgenic mice on a high fat/cholesterol (HFC) diet (n=12) or on a normal mouse chow

  18. Modeling grain size variations of aeolian gypsum deposits at White Sands, New Mexico, using AVIRIS imagery

    Science.gov (United States)

    Ghrefat, H.A.; Goodell, P.C.; Hubbard, B.E.; Langford, R.P.; Aldouri, R.E.

    2007-01-01

    also show that there are no significant differences between modeled and laboratory-measured grain size values. Hyperspectral grain size modeling can help to determine dynamic processes shaping the formation of the dunes such as wind directions, and the relative strengths of winds through time. This has implications for studying such processes on other planetary landforms that have mineralogy with unique absorption bands in VNIR-SWIR hyperspectral data. ?? 2006 Elsevier B.V. All rights reserved.

  19. Morphological Study Of Palladium Thin Films Deposited By Sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Salcedo, K L; Rodriguez, C A [Grupo Plasma Laser y Aplicaciones, Ingenieria Fisica, Universidad Tecnologica de Pereira (Colombia); Perez, F A [WNANO, West Virginia University (United States); Riascos, H [Grupo Plasma Laser y Aplicaciones, Departamento de Fisica, Universidad Tecnologica de Pereira (Colombia)

    2011-01-01

    This paper presents a morphological analysis of thin films of palladium (Pd) deposited on a substrate of sapphire (Al{sub 2}O{sub 3}) at a constant pressure of 3.5 mbar at different substrate temperatures (473 K, 523 K and 573 K). The films were morphologically characterized by means of an Atomic Force Microscopy (AFM); finding a relation between the roughness and the temperature. A morphological analysis of the samples through AFM was carried out and the roughness was measured by simulating the X-ray reflectivity curve using GenX software. A direct relation between the experimental and simulation data of the Palladium thin films was found.

  20. Effects of build parameters on linear wear loss in plastic part produced by fused deposition modeling

    Science.gov (United States)

    Mohamed, Omar Ahmed; Masood, Syed Hasan; Bhowmik, Jahar Lal

    2017-07-01

    Fused Deposition Modeling (FDM) is one of the prominent additive manufacturing technologies for producing polymer products. FDM is a complex additive manufacturing process that can be influenced by many process conditions. The industrial demands required from the FDM process are increasing with higher level product functionality and properties. The functionality and performance of FDM manufactured parts are greatly influenced by the combination of many various FDM process parameters. Designers and researchers always pay attention to study the effects of FDM process parameters on different product functionalities and properties such as mechanical strength, surface quality, dimensional accuracy, build time and material consumption. However, very limited studies have been carried out to investigate and optimize the effect of FDM build parameters on wear performance. This study focuses on the effect of different build parameters on micro-structural and wear performance of FDM specimens using definitive screening design based quadratic model. This would reduce the cost and effort of additive manufacturing engineer to have a systematic approachto make decision among the manufacturing parameters to achieve the desired product quality.

  1. Size- and concentration-dependent deposition of fluorescent silica colloids in saturated sand columns: transport experiments and modeling.

    Science.gov (United States)

    Vitorge, Elsa; Szenknect, Stéphanie; Martins, Jean M F; Gaudet, Jean-Paul

    2013-08-01

    This study investigates the size and concentration effects on the transport of silica colloids in columns of sandy aquifer material. Colloid transport experiments were performed with specifically developed fluorescent labeled silica colloids in columns of a repacked natural porous medium under hydro-geochemical conditions representative of sandy aquifers. Breakthrough curves and vertical deposition profiles of colloids were measured for various colloid concentrations and sizes. The results showed that for a given colloid concentration injected, deposition increased when increasing the size of the colloids. For a given colloid size, retention was also shown to be highly concentration-dependent with a non-monotonous pattern presenting low and high concentration specificities. Deposition increases when increasing both size and injected concentration, until a threshold concentration is reached, above which retention decreases, thus increasing colloid mobility. Results observed above the threshold concentration agree with a classical blocking mechanism typical of a high concentration regime. Results observed at lower colloid concentrations were not modeled with a classical blocking model and a depth- and time-dependent model with a second order kinetic law was necessary to correctly fit the experimental data in the entire range of colloid concentrations with a single set of parameters for each colloidal size. The colloid deposition mechanisms occuring at low concentrations were investigated through a pore structure analysis carried out with Mercury Intrusion Porosimetry and image analysis. The determined pore size distribution permitted estimation of the maximal retention capacity of the natural sand as well as some low flow zones. Altogether, these results stress the key role of the pore space geometry of the sand in controlling silica colloids deposition under hydro-geochemical conditions typical of sandy aquifers. Our results also showed originally that colloid

  2. Combined time-lapse magnetic resonance imaging and modeling to investigate colloid deposition and transport in porous media.

    Science.gov (United States)

    Lehoux, Alizée P; Faure, Pamela; Lafolie, François; Rodts, Stéphane; Courtier-Murias, Denis; Coussot, Philippe; Michel, Eric

    2017-10-15

    Colloidal particles can act as vectors of adsorbed pollutants in the subsurface, or be themselves pollutants. They can reach the aquifer and impair groundwater quality. The mechanisms of colloid transport and deposition are often studied in columns filled with saturated porous media. Time-lapse profiles of colloid concentration inside the columns have occasionally been derived from magnetic resonance imaging (MRI) data recorded in transport experiments. These profiles are valuable, in addition to particle breakthrough curves (BTCs), for testing and improving colloid transport models. We show that concentrations could not be simply computed from MRI data when both deposited and suspended colloids contributed to the signal. We propose a generic method whereby these data can still be used to quantitatively appraise colloid transport models. It uses the modeled suspended and deposited particle concentrations to compute modeled MRI data that are compared to the experimental data. We tested this method by performing transport experiments with sorbing colloids in sand, and assessed for the first time the capacity of the model calibrated from BTCs to reproduce the MRI data. Interestingly, the dispersion coefficient and deposition rate calibrated from the BTC were respectively overestimated and underestimated compared with those calibrated from the MRI data, suggesting that these quantities, when determined from BTCs, need to be interpreted with care. In a broader perspective, we consider that combining MRI and modeling offers great potential for the quantitative analysis of complex MRI data recorded during transport experiments in complex environmentally relevant porous media, and can help improve our understanding of the fate of colloids and solutes, first in these media, and later in soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Error analysis: How precise is fused deposition modeling in fabrication of bone models in comparison to the parent bones?

    Directory of Open Access Journals (Sweden)

    M V Reddy

    2018-01-01

    Full Text Available Background: Rapid prototyping (RP is used widely in dental and faciomaxillary surgery with anecdotal uses in orthopedics. The purview of RP in orthopedics is vast. However, there is no error analysis reported in the literature on bone models generated using office-based RP. This study evaluates the accuracy of fused deposition modeling (FDM using standard tessellation language (STL files and errors generated during the fabrication of bone models. Materials and Methods: Nine dry bones were selected and were computed tomography (CT scanned. STL files were procured from the CT scans and three-dimensional (3D models of the bones were printed using our in-house FDM based 3D printer using Acrylonitrile Butadiene Styrene (ABS filament. Measurements were made on the bone and 3D models according to data collection procedures for forensic skeletal material. Statistical analysis was performed to establish interobserver co-relation for measurements on dry bones and the 3D bone models. Statistical analysis was performed using SPSS version 13.0 software to analyze the collected data. Results: The inter-observer reliability was established using intra-class coefficient for both the dry bones and the 3D models. The mean of absolute difference is 0.4 that is very minimal. The 3D models are comparable to the dry bones. Conclusions: STL file dependent FDM using ABS material produces near-anatomical 3D models. The high 3D accuracy hold a promise in the clinical scenario for preoperative planning, mock surgery, and choice of implants and prostheses, especially in complicated acetabular trauma and complex hip surgeries.

  4. Modeling of gas-phase chemistry in the chemical vapor deposition of polysilicon in a cold wall system

    Energy Technology Data Exchange (ETDEWEB)

    Toprac, A.J.; Edgar, T.F.; Trachtenberg, I. (Univ. of Texas, Austin, TX (United States). Dept. of Chemical Engineering)

    1993-06-01

    The relative contribution of gas-phase chemistry to deposition processes is an important issue both from the standpoint of operation and modeling of these processes. In polysilicon deposition from thermally activated silane in a cold wall rapid thermal chemical vapor deposition (RTCVD) system, the relative contribution of gas-phase chemistry to the overall deposition rate was examined by a mass-balance model. Evaluating the process at conditions examined experimentally, the model indicated that gas-phase reactions may be neglected to good accuracy in predicting polysilicon deposition rate. The model also provided estimates of the level of gas-phase generated SiH[sub 2] associated with deposition on the cold-process chamber walls.

  5. Study of the Implications of Whitecap Intermittency on the Uniform Sea-salt Aerosol Source Approximation and Deposition Velocity

    National Research Council Canada - National Science Library

    Hoppel, William A; Caffrey, Peter F

    2007-01-01

    The source function and deposition velocity of sea-salt particles used in large-scale models assumes that the source and deposition is uniform over areas large compared to the horizontal grid spacing...

  6. A COMPARISON OF THE TENSILE STRENGTH OF PLASTIC PARTS PRODUCED BY A FUSED DEPOSITION MODELING DEVICE

    Directory of Open Access Journals (Sweden)

    Juraj Beniak

    2015-12-01

    Full Text Available Rapid Prototyping systems are nowadays increasingly used in many areas of industry, not only for producing design models but also for producing parts for final use. We need to know the properties of these parts. When we talk about the Fused Deposition Modeling (FDM technique and FDM devices, there are many possible settings for devices and models which could influence the properties of a final part. In addition, devices based on the same principle may use different operational software for calculating the tool path, and this may have a major impact. The aim of this paper is to show the tensile strength value for parts produced from different materials on the Fused Deposition Modeling device when the horizontal orientation of the specimens is changed.

  7. Which measurement strategies to improve spatial erosion and deposition patterns modelling?

    Science.gov (United States)

    Pineux, Nathalie; Maugnard, Alexandre; Swerts, Gilles; Bielders, Charles; Degré, Aurore

    2014-05-01

    Validation of the erosion models requires field data. To date, many authors continue to highlight the paucity of accurate field observations and long-term enough studies. The fields observations are often put aside because these measures are difficult to obtain: weighty experimental devices, climatic dependence, … Hence the models are evolving and propose refined calculation procedures including for instance the calculation of landscape evolution. The need of field data therefore increases and new measuring strategies should arise. In the centre of Belgium we choose an agricultural watershed quite representative of the local context. It covers 124 ha of loamy soil with more than 90% of arable land and a weak proportion of forest and artificial lands. The slope ranges between 0 and 9%. Instrumentation on the watershed includes meteorological observations and discharge measurement coupled with water sampling at different outlets. The weather data (radiation, temperature, wind velocity, relative humidity and rainfall) and discharge measurement (comparison between Doppler and pressure sensors) will allow us to model the hydrological behaviour of the catchment. Rainfall readings (tipping buckets) are completed with erosivity readings (disdrometer). Erosivity, together with soil data, land use and agricultural practices observations on field, will be used as entry in the Landsoil model. The sediment samplings at 3 points in the catchment will give an insight of the sediment delivery of 3 subcatchments. The Landsoil model calculates the evolution of the DTM through time. This cannot be compared to measurements at the outlet and requires further data collection. Older elevation data and/or archaeological data are a possible source of information even if their precision remains scarce in our context. 1950's soil surveys are on the contrary really informative since they detail the horizons depth in a spatial way and can be compared to new observation across the watershed

  8. 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.

  9. Reactive flow models of the Anarraaq Zn-Pb-Ag deposit, Red Dog district, Alaska

    Science.gov (United States)

    Schardt, Christian; Garven, Grant; Kelley, Karen D.; Leach, David L.

    2008-09-01

    The Red Dog ore deposit district in the Brooks Range of northern Alaska is host to several high-grade, shale-hosted Zn + Pb deposits. Due to the complex history and deformation of these ore deposits, the geological and hydrological conditions at the time of formation are poorly understood. Using geological observations and fluid inclusion data as constraints, numerical heat and fluid flow simulations of the Anarraaq ore deposit environment and coupled reactive flow simulations of a section of the ore body were conducted to gain more insight into the conditions of ore body formation. Results suggest that the ore body and associated base metal zonation may have formed by the mixing of oxidized, saline, metal-bearing hydrothermal fluids (<200°C) with reducing, HS-rich pore fluids within radiolarite-rich host rocks. Sphalerite and galena concentrations and base metal sulfide distribution are primarily controlled by the nature of the pore fluids, i.e., the extent and duration of the HS- source. Forward modeling results also predict the distribution of pyrite and quartz in agreement with field observations and indicate a reaction front moving from the initial mixing interface into the radiolarite rocks. Heuristic mass calculations suggest that ore grades and base metal accumulation comparable to those found in the field (18% Zn, 5% Pb) are predicted to be reached after about 0.3 My for initial conditions (30 ppm Zn, 3 ppm Pb; 20% deposition efficiency).

  10. Study of nozzle deposit formation mechanism for direct injection gasoline engines; Chokufun gasoline engine yo nozzle no deposit seisei kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Kinoshita, M.; Saito, A. [Toyota Central Research and Development Labs., Inc., Aichi (Japan); Matsushita, S. [Toyota Motor Corp., Aichi (Japan); Shibata, H. [Nippon Soken, Inc., Tokyo (Japan); Niwa, Y. [Denso Corp., Aichi (Japan)

    1997-10-01

    Nozzles in fuel injectors for direct injection gasoline engines are exposed to high temperature combustion gases and soot. In such a rigorous environment, it is a fear that fuel flow rate changes in injectors by deposit formation on nozzles. Fundamental factors of nozzle deposit formation were investigated through injector bench tests and engine dynamometer tests. Deposit formation processes were observed by SEM through engine dynamometer tests. The investigation results reveal nozzle deposit formation mechanism and how to suppress the deposit. 4 refs., 8 figs., 3 tabs.

  11. Operational Efficiency of Bank Loans and Deposits: A Case Study of Vietnamese Banking System

    Directory of Open Access Journals (Sweden)

    Tram Nguyen

    2018-01-01

    Full Text Available This paper examines whether there is a causal relationship between bank loans and deposits in the Vietnamese banking system and the efficiency of the use of loans and deposits by the Vietnamese banks. In a country such as Vietnam, where inter-bank money markets are relatively underdeveloped, one would expect a reasonably strong relationship between deposits and loans. A pooled cross-sectional sample of financial ratios is collected from annual reports of 44 Vietnamese banks covering the period 2008–2015. The explanatory power of instrumental variables in relation to the endogenous variables is tested. A deterministic frontier model based on corrected ordinary least squares, estimated by three-stage least squares on a simultaneous equations model, is employed to derive the frontiers for the sampled banks as well as to estimate the causality between bank loans and deposits. Our findings suggest that, in an underdeveloped banking system such as Vietnam, bank deposits have a positive and significant impact on bank loans, but the reverse relationship is not significant. It is further suggested that in deposit-taking and loan-creating activities, Vietnamese banks performed moderately well over the period examined; however, in the near future, they should start to focus more on deposit-taking activities.

  12. Field Measurements and Modeling of Dust Transport and Deposition on a Hawaiian Volcano

    Science.gov (United States)

    Douglas, M.; Stock, J. D.; Cerovski-Darriau, C.; Bishaw, K.; Bedford, D.

    2017-12-01

    The western slopes of Hawaii's Mauna Kea volcano are mantled by fine-grained soils that record volcanic airfall and eolian deposition. Where exposed, strong winds transport this sediment across west Hawaii, affecting tourism and local communities by decreasing air and water quality. Operations on US Army's Ke'amuku Maneuver Area (KMA) have the potential to increase dust flux from these deposits. To understand regional dust transport and composition, the USGS established 18 ground monitoring sites and sampling locations surrounding KMA. For over three years, each station measured vertical and horizontal dust flux while co-located anemometers measured wind speed and direction. We use these datasets to develop a model for dust supply and transport to assess whether KMA is a net dust sink or source. We find that horizontal dust flux rates are most highly correlated with entrainment threshold wind speeds of 8 m/s. Using a dust model that partitions measured horizontal dust flux into inward- and outward-directed components, we predict that KMA is currently a net dust sink. Geochemical analysis of dust samples illustrates that organics and pedogenic carbonate make up to 70% of their mass. Measured vertical dust deposition rates of 0.005 mm/m2/yr are similar to deposition rates of 0.004 mm/m2/yr predicted from the divergence of dust across KMA's boundary. These rates are low compared to pre-historic rates of 0.2-0.3 mm/yr estimated from radiocarbon dating of buried soils. Therefore, KMA's soils record persistent deposition both over past millennia and at present at rates that imply infrequent, large dust storms. Such events led to soil-mantled topography in an otherwise rocky Pleistocene volcanic landscape. A substantial portion of fine-grained soils in other leeward Hawaiian Island landscapes may have formed from similar eolian deposition, and not direct weathering of parent rock.

  13. Fused Deposition Modeling (FDM) 3D Printed Tablets for Intragastric Floating Delivery of Domperidone.

    Science.gov (United States)

    Chai, Xuyu; Chai, Hongyu; Wang, Xiaoyu; Yang, Jingjing; Li, Jin; Zhao, Yan; Cai, Weimin; Tao, Tao; Xiang, Xiaoqiang

    2017-06-06

    The aim of this study was to explore the feasibility of fused deposition modeling (FDM) 3D printing to prepare intragastric floating sustained release (FSR) tablets. Domperidone (DOM), an insoluble weak base, was chosen as a model drug to investigate the potential of FSR in increasing its oral bioavailability and reducing its administration frequency. DOM was successfully loaded into hydroxypropyl cellulose (HPC) filaments using hot melt extrusion (HME). The filaments were then printed into hollow structured tablets through changing the shell numbers and the infill percentages. Physical characterization results indicated that the majority of DOM gradually turned into the amorphous form during the fabrication process. The optimized formulation (contain 10% DOM, with 2 shells and 0% infill) exhibited the sustained release characteristic and was able to float for about 10 h in vitro. Radiographic images showed that the BaSO 4 -labeled tablets were retained in the stomach of rabbits for more than 8 h. Furthermore, pharmacokinetic studies showed the relative bioavailability of the FSR tablets compared with reference commercial tablets was 222.49 ± 62.85%. All the results showed that FDM based 3D printing might be a promising way to fabricate hollow tablets for the purpose of intragastric floating drug delivery.

  14. PCL/PLA Polymer Composite Filament Fabrication using Full Factorial Design (DOE) for Fused Deposition Modelling

    Science.gov (United States)

    Haq, R. H. A.; Khairilhijra, K. Rd.; Wahab, M. S.; Sa’ude, N.; Ibrahim, M.; Marwah, O. M. F.; Yusof, M. S.; Rahman, M. N. A.; Ariffin, A. M. T.; Hassan, M. F.; Yunos, M. Z.; Adzila, S.

    2017-10-01

    In this study, Polycaprolactone / Polylactice Acid (PCL/PLA) composite are used to fabricate filament wire with the specific diameter, which is in the range of 1.75 to 1.80 mm. Full factorial experimental design technique was used to study the main effects and the interaction effects between operational parameter which is (A) die temperature, (B) roller puller speed, (C) spindle speed and (D) inlet temperature. Besides that, there are two levels (-1 and +1) and the response are filament wire diameter. There are 16 numbers of runs and plus 8 centre points per blocks which makes the runs into 24 runs. From the experiment it shows that there are four factor that are significant effects on the filament wire diameter which is A, B, C and BC. The optimum parameter setting are also determined and there are 10 suggestions to achieve the target with different setting of parameter. The margin error for confirmation run is below than 15% when the parameter set at 6 Hz spindle speed, 4.99 rpm roller puller, 100.31 °C die temperature and 79.65 °C inlet temperature which can be noted that the confirmation run result is acceptable. The optimization parameter setting can use to continue in Fused Deposition Modelling (FDM). Filament wire from PCL/PLA are succesfully fabricated with acceptable diameter size and ready to be used for Fused Depotion Modelling process (FDM).

  15. Two depositional models for Pliocene coastal plain fluvial systems, Goliad Formation, south Texas Gulf Coastal plain

    International Nuclear Information System (INIS)

    Hoel, H.D.; Galloway, W.E.

    1983-01-01

    The Goliad Formation consists of four depositional systems-the Realitos and Mathis bed-load fluvial systems in the southwest and the Cuero and Eagle Lake mixed-load fluvial systems in the northeast. Five facies are recognized in the Realitos and Mathis bed-load fluvial systems: (1) primary channel-fill facies, (2) chaotic flood channel-fill facies, (3) complex splay facies, (4) flood plain facies, and (5) playa facies. A model for Realitos-Mathis depositional environments shows arid-climate braided stream complexes with extremely coarse sediment load, highly variable discharge, and marked channel instability. Broad, shallow, straight to slightly sinuous primary channels were flanked by wide flood channels. Flood channels passed laterally into broad, low-relief flood plains. Small playas occupied topographic lows near large channel axes. Three facies are recognized in the Cuero and Eagle Lake mixed-load fluvial systems: (1) channel-fill facies, (2) crevasse splay facies, and (3) flood plain facies. A model for Cuero-Eagle Lake depositional environments shows coarse-grained meander belts in a semi-arid climate. Slightly to moderately sinuous meandering streams were flanked by low, poorly developed natural levees. Crevasse splays were common, but tended to be broad and ill-defined. Extensive, low-relief flood plains occupied interaxial areas. The model proposed for the Realitos and Mathis fluvial systems may aid in recognition of analogous ancient depositional systems. In addition, since facies characteristics exercise broad controls on Goliad uranium mineralization, the proposed depositional models aid in defining target zones for Goliad uranium exploration

  16. Studies on deposition of gadolinium from its nitrate solution of zircaloy-2 surfaces

    International Nuclear Information System (INIS)

    Shah, G.C.; Unny, V.K.P.; Vartak, D.G.

    1981-01-01

    Gadolinium nitrate solution (25000 ppm) is proposed as a neutron poison in tertiary shut down system of R-5 reactor at Trombay, Bombay. The gadolinium nitrate solution when in contact with the zircaloy tube can get deposited and thus, affect the reactivity of the reactor during operation. Experiments were conducted to evaluate the rate of deposition of gadolinium on zircaloy-2 surfaces at various temperatures and at different periods of time. Studies were also conducted to determine the deposition of gadolinium when exposed to various 60 Co γ-ray irradiation doses. The studies indicated that deposition of gadolinium increases with increase in temperature while there was no increase in rate of deposition by 60 Co γ-ray irradiation upto 440 Mrads. (author)

  17. An oxygen isotope study on hydrothermal sources of granite-type uranium deposits in South China

    International Nuclear Information System (INIS)

    Yongfei, Z.

    1987-01-01

    The usefulness of oxygen isotope measurements in solving problems of hydrothermal sources has been demonstrated in a number of detailed studies of the granite type uranium deposits in this paper. Remarkly the granite-type uranium deposits in Southr China have been shown to have formed from magmatic water, meteoric water, of mixtures of both the above, and origin of waters in the ore-forming fluid may be different for differing uranium deposits ore differing stages of the mineralization. Consequences obtained in this study for typical uranium deposits of different age and geologic sitting agree well with that obtained by other geologic-geochemical investigation. Furthermore, not only meteoric water is of importance to origin and evolution of the ore-forming fluid, but also mixing of waters from different sources is considered to be one of the most characteristic features of many hydrothermal uranium deposits related to granitoids or volcanics. (C.D.G.) [pt

  18. Physical and mathematical modeling of transient infiltration through shallow layered pyroclastic deposits

    Science.gov (United States)

    Damiano, Emilia; Greco, Roberto; Guida, Andrea; Olivares, Lucio; Picarelli, Luciano

    2017-04-01

    Layered pyroclastic deposits covering steep slopes, characteristic of large mountainous areas of Campania (southern Italy), are often affected by shallow landslides triggered by heavy rainfall events. In fact, the equilibrium of such deposits is usually guaranteed by the contribution to soil shear strength offered by soil suction, which decreases during wetting. As the return period of the triggering events has been in many cases not extreme, other factors concur to establish triggering conditions. In this respect, heterogeneities, strongly affecting transient infiltration, may in some cases play a crucial role. In this study, the effect of the presence of soil layers, characterized by markedly different hydraulic properties, on the rainwater infiltration process is investigated. In fact, the pyroclastic covers of Campania, being the result of the deposition of materials originated by several eruptions of the nearby volcanic complexes, usually consist of alternating layers of ashes (silty sands) and pumices (gravel with sand). The presence of coarse-textured pumices between finer ashes strongly affects the infiltration process. In fact, the pumices, which are characterized by saturated hydraulic conductivity larger than ashes, are capable of retaining less water than ashes in unsaturated conditions, so that their unsaturated hydraulic conductivity is usually very small. Hence, depending on the water potential distribution throughout the cover at the onset of rainfall, pumices may act as a barrier to the propagation of the wet front (the so-called capillary barrier effect), or, approaching saturation, let the water pass through them very quickly. Such a complex behavior has been studied by means of a series of infiltration experiments carried out in an instrumented flume in the Geotechnical Laboratory of the University of Campania (http://www.dicdea.unina2.it/it/dipartimento/laboratori/laboratorio-di-geotecnica). Starting from different initial moisture conditions

  19. A Computational Study of Nasal Spray Deposition Pattern in Four Ethnic Groups.

    Science.gov (United States)

    Keeler, Jarrod A; Patki, Aniruddha; Woodard, Charles R; Frank-Ito, Dennis O

    2016-04-01

    Very little is known about the role of nasal morphology due to ethnic variation on particle deposition pattern in the sinonasal cavity. This preliminary study utilizes computational fluid dynamics (CFD) modeling to investigate sinonasal airway morphology and deposition patterns of intranasal sprayed particles in the nose and sinuses of individuals from four different ethnic groups: African American (Black); Asian; Caucasian; and Latin American. Sixteen subjects (four from each ethnic group) with "normal" sinus protocol computed tomography (CT) were selected for CFD analysis. Three-dimensional reconstruction of each subject's sinonasal cavity was created from their personal CT images. CFD simulations were carried out in ANSYS Fluent(™) in two phases: airflow phase was done by numerically solving the Navier-Stokes equations for steady state laminar inhalation; and particle dispersed phase was solved by tracking injected (sprayed) particles through the calculated airflow field. A total of 10,000 particle streams were released from each nostril, 1000 particles per diameter ranging from 5 μm to 50 μm, with size increments of 5 μm. As reported in the literature, Caucasians (5.31 ± 0.42 cm(-1)) and Latin Americans (5.16 ± 0.40cm(-1)) had the highest surface area to volume ratio, while African Americans had highest nasal index (95.91 ± 2.22). Nasal resistance (NR) was highest among Caucasians (0.046 ± 0.008 Pa.s/mL) and Asians (0.042 ± 0.016Pa.s/mL). Asians and African Americans had the most regions with particle deposition for small (5 μm-15 μm) and large (20 μm-50 μm) particle sizes, respectively. Asians and Latin Americans individuals had the most consistent regional particle deposition pattern in the main nasal cavities within their respective ethnic groups. Preliminary results from these ethnic groups investigated showed that Caucasians and Latin Americans had the least patent nasal cavity. Furthermore, Caucasians

  20. Pilot‐scale investigation and CFD modeling of particle deposition in low‐dust monolithic SCR DeNOx catalysts

    DEFF Research Database (Denmark)

    Heiredal, Michael Lykke; Jensen, Anker Degn; Thøgersen, Joakim Reimer

    2013-01-01

    Deposition of particles in selective catalytic reduction DeNOx monolithic catalysts was studied by low‐dust pilot‐scale experiments. The experiments showed a total deposition efficiency of about 30%, and the deposition pattern was similar to that observed in full‐scale low‐dust applications. On e...

  1. Predictive modeling of slope deposits and comparisons of two small areas in Northern Germany

    Science.gov (United States)

    Shary, Peter A.; Sharaya, Larisa S.; Mitusov, Andrew V.

    2017-08-01

    Methods for correct quantitative comparison of several terrains are important in the development and use of quantitative landscape evolution models, and they need to introduce specific modeling parameters. We introduce such parameters and compare two small terrains with respect to the link slope-valley for the description of slope deposits (colluvium) in them. We show that colluvium accumulation in small areas cannot be described by linear models and thus introduce non-linear models. Two small areas, Perdoel (0.29 ha) and Bornhöved (3.2 ha), are studied. Slope deposits in the both are mainly in dry valleys, with a total thickness Mtotal up to 2.0 m in Perdoel and up to 1.2 m in Bornhöved. Parent materials are mainly Pleistocene sands aged 30 kyr BP. Exponential models of multiple regression that use a 1-m LiDAR DEM (digital elevation model) explained 70-93% of spatial variability in Mtotal. Parameters DH12 and DV12 of horizontal and vertical distances are introduced that permit to characterize and compare conditions of colluvium formation for various terrains. The study areas differ 3.7 times by the parameter DH12 that describes a horizontal distance from thalwegs at which Mtotal diminishes 2.72 times. DH12 is greater in Bornhöved (29.7 m) than in Perdoel (8.12 m). We relate this difference in DH12 to the distinction between types of the link slope-valley: a regional type if catchment area of a region outside a given small area plays an important role, and a local type when accumulation of colluvium from valley banks within a small area is of more importance. We argue that the link slope-valley is regional in Perdoel and local in Bornhöved. Peaks of colluvium thickness were found on thalwegs of three studied valleys by both direct measurements in a trench, and model surfaces of Mtotal. A hypothesis on the formation mechanism of such peaks is discussed. The parameter DV12 describes a vertical distance from a peak of colluvium thickness along valley bottom at

  2. Fundamental studies of the mechanisms of slag deposit formation: Studies on initiation, growth and sintering in the formation of utility boiler deposits: Topical technical report

    Energy Technology Data Exchange (ETDEWEB)

    Tangsathitkulchai, M.; Austin, L.G.

    1986-03-01

    Three laboratory-scale devices were utilized to investigate the mechanisms of the initiation, growth and sintering process involved in the formation of boiler deposits. Sticking apparatus investigations were conducted to study deposit initiation by comparing the adhesion behavior of the ash drops on four types of steel-based heat exchanger materials under the conditions found in a utility boiler and an entrained slagging gasifier. In addition, the adhesion behavior of the ash drops on a reduced steel surface were investigated. All the ash drops studied in this investigation were produced from bituminous coals.

  3. Modelling Deposition and Erosion rates with RadioNuclides (MODERN) - Part 1: A new conversion model to derive soil redistribution rates from inventories of fallout radionuclides.

    Science.gov (United States)

    Arata, Laura; Meusburger, Katrin; Frenkel, Elena; A'Campo-Neuen, Annette; Iurian, Andra-Rada; Ketterer, Michael E; Mabit, Lionel; Alewell, Christine

    2016-10-01

    The measurement of fallout radionuclides (FRN) has become one of the most commonly used tools to quantify sediment erosion or depositional processes. The conversion of FRN inventories into soil erosion and deposition rates is done with a variety of models, which suitability is dependent on the selected FRN, soil cultivation (ploughed or unploughed) and movement (erosion or deposition). The authors propose a new conversion model, which can be easily and comprehensively used for different FRN, land uses and soil redistribution processes. The new model MODERN (Modelling Deposition and Erosion rates with RadioNuclides) considers the precise depth distribution of any FRN at the reference site, and allows adapting it for any specific site conditions. MODERN adaptability and performance in converting different FRN inventories is discussed for a theoretical case as well as for two already published case studies i.e. a 137 Cs study in an alpine and unploughed area in the Aosta valley (Italy) and a 210 Pb ex study on a ploughed area located in the Transylvanian Plain (Romania). The tests highlight a highly significant correspondence (i.e. correlation factor of 0.91) between the results of MODERN and the published results of other models currently used by the FRN scientific community (i.e. the Profile Distribution Model and the Mass Balance Model). The development and the cost free accessibility of MODERN (see modern.umweltgeo.unibas.ch) will ensure the promotion of wider application of FRNs for tracing soil erosion and sedimentation. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. The rudist buildup depositional model, reservoir architecture and development strategy of the cretaceous Sarvak formation of Southwest Iran

    Directory of Open Access Journals (Sweden)

    Yang Du

    2015-03-01

    Full Text Available This paper studies the lithofacies, sedimentary facies, depositional models and reservoir architecture of the rudist-bearing Sar-3 zone of Cretaceous Sarvak in the Southwest of Iran by utilizing coring, thin section, XRD data of five coring wells and 3D seismic data. Research results include the following: According to lithofacies features and their association, the rudist-mound and tidal flat are the main microfacies in the Sar-3 depositional time. By investigating the regional tectonic setting and seismic interpretation, a depositional model was built for the Sar-3 zone, which highlights four key points: 1 The distribution of the rudist-buildup is controlled by the paleo-high. 2 The build-up outside of the wide colonize stage but reached the wave-base level in a short time by regression and formation uplift, and was destroyed by the high energy current, then forming the moundy allochthonous deposition after being dispersed and redeposited. 3 The tidal flat develops widely in the upper Sar-3, and the deposition thickness depends on the paleo-structure. The tidal channel develops in the valley and fringe of the Paleo-structure. 4 The exposure within the leaching effect by the meteoric water of the top of Sar-3 is the main controlling factor of the reservoir vertical architecture. The Sar-3 zone featured as the dualistic architecture consists of two regions: the lower is the rudist reef limestone reservoir and the upper is the tidal condense limestone interlayer. The thickness of each is controlled by the paleo-structure. The Paleo-high zone is the preferential development zone. Based on reservoir characteristics of the different zones, a targeted development strategy has been proposed. Keeping the trajectory in the middle of the oil-layer in the paleo-high, and in the paleo-low, make the trajectory crossing the oil-zone and then keep it in the lower.

  5. Use of regression‐based models to map sensitivity of aquatic resources to atmospheric deposition in Yosemite National Park, USA

    Science.gov (United States)

    Clow, David W.; Nanus, Leora; Huggett, Brian

    2010-01-01

    An abundance of exposed bedrock, sparse soil and vegetation, and fast hydrologic flushing rates make aquatic ecosystems in Yosemite National Park susceptible to nutrient enrichment and episodic acidification due to atmospheric deposition of nitrogen (N) and sulfur (S). In this study, multiple linear regression (MLR) models were created to estimate fall‐season nitrate and acid neutralizing capacity (ANC) in surface water in Yosemite wilderness. Input data included estimated winter N deposition, fall‐season surface‐water chemistry measurements at 52 sites, and basin characteristics derived from geographic information system layers of topography, geology, and vegetation. The MLR models accounted for 84% and 70% of the variance in surface‐water nitrate and ANC, respectively. Explanatory variables (and the sign of their coefficients) for nitrate included elevation (positive) and the abundance of neoglacial and talus deposits (positive), unvegetated terrain (positive), alluvium (negative), and riparian (negative) areas in the basins. Explanatory variables for ANC included basin area (positive) and the abundance of metamorphic rocks (positive), unvegetated terrain (negative), water (negative), and winter N deposition (negative) in the basins. The MLR equations were applied to 1407 stream reaches delineated in the National Hydrography Data Set for Yosemite, and maps of predicted surface‐water nitrate and ANC concentrations were created. Predicted surface‐water nitrate concentrations were highest in small, high‐elevation cirques, and concentrations declined downstream. Predicted ANC concentrations showed the opposite pattern, except in high‐elevation areas underlain by metamorphic rocks along the Sierran Crest, which had relatively high predicted ANC (>200 μeq L−1). Maps were created to show where basin characteristics predispose aquatic resources to nutrient enrichment and acidification effects from N and S deposition. The maps can be used to help guide

  6. Use of regression-based models to map sensitivity of aquatic resources to atmospheric deposition in Yosemite National Park, USA

    Science.gov (United States)

    Clow, D. W.; Nanus, L.; Huggett, B. W.

    2010-12-01

    An abundance of exposed bedrock, sparse soil and vegetation, and fast hydrologic flushing rates make aquatic ecosystems in Yosemite National Park susceptible to nutrient enrichment and episodic acidification due to atmospheric deposition of nitrogen (N) and sulfur (S). In this study, multiple-linear regression (MLR) models were created to estimate fall-season nitrate and acid neutralizing capacity (ANC) in surface water in Yosemite wilderness. Input data included estimated winter N deposition, fall-season surface-water chemistry measurements at 52 sites, and basin characteristics derived from geographic information system layers of topography, geology, and vegetation. The MLR models accounted for 84% and 70% of the variance in surface-water nitrate and ANC, respectively. Explanatory variables (and the sign of their coefficients) for nitrate included elevation (positive) and the abundance of neoglacial and talus deposits (positive), unvegetated terrain (positive), alluvium (negative), and riparian (negative) areas in the basins. Explanatory variables for ANC included basin area (positive) and the abundance of metamorphic rocks (positive), unvegetated terrain (negative), water (negative), and winter N deposition (negative) in the basins. The MLR equations were applied to 1407 stream reaches delineated in the National Hydrography Dataset for Yosemite, and maps of predicted surface-water nitrate and ANC concentrations were created. Predicted surface-water nitrate concentrations were highest in small, high-elevation cirques, and concentrations declined downstream. Predicted ANC concentrations showed the opposite pattern, except in high-elevation areas underlain by metamorphic rocks along the Sierran Crest, which had relatively high predicted ANC (>200 µeq L-1). Maps were created to show where basin characteristics predispose aquatic resources to nutrient enrichment and acidification effects from N and S deposition. The maps can be used to help guide development of

  7. A dermal model for spray painters, part I : subjective exposure modelling of spray paint deposition

    NARCIS (Netherlands)

    Brouwer, D.H.; Semple, S.; Marquart, J.; Cherrie, J.W.

    2001-01-01

    The discriminative power of existing dermal exposure models is limited. Most models only allow occupational hygienists to rank workers between and within workplaces according to broad bands of dermal exposure. No allowance is made for the work practices of different individuals. In this study a

  8. Modelling stomatal ozone flux and deposition to grassland communities across Europe

    Energy Technology Data Exchange (ETDEWEB)

    Ashmore, M.R. [Environment Department, University of York, Heslington, York YO10 5DD (United Kingdom)]. E-mail: ma512@york.ac.uk; Bueker, P. [Stockholm Environment Institute at York, University of York, York YO10 5DD (United Kingdom); Emberson, L.D. [Stockholm Environment Institute at York, University of York, York YO10 5DD (United Kingdom); Terry, A.C. [Environment Department, University of York, Heslington, York YO10 5DD (United Kingdom); Toet, S. [Environment Department, University of York, Heslington, York YO10 5DD (United Kingdom)

    2007-04-15

    Regional scale modelling of both ozone deposition and the risk of ozone impacts is poorly developed for grassland communities. This paper presents new predictions of stomatal ozone flux to grasslands at five different locations in Europe, using a mechanistic model of canopy development for productive grasslands to generate time series of leaf area index and soil water potential as inputs to the stomatal component of the DO{sub 3}SE ozone deposition model. The parameterisation of both models was based on Lolium perenne, a dominant species of productive pasture in Europe. The modelled seasonal time course of stomatal ozone flux to both the whole canopy and to upper leaves showed large differences between climatic zones, which depended on the timing of the start of the growing season, the effect of soil water potential, and the frequency of hay cuts. Values of modelled accumulated flux indices and the AOT40 index showed a five-fold difference between locations, but the locations with the highest flux differed depending on the index used; the period contributing to the accumulation of AOT40 did not always coincide with the modelled period of active ozone canopy uptake. Use of a fixed seasonal profile of leaf area index in the flux model produced very different estimates of annual accumulated total canopy and leaf ozone flux when compared with the flux model linked to a simulation of canopy growth. Regional scale model estimates of both the risks of ozone impacts and of total ozone deposition will be inaccurate unless the effects of climate and management in modifying grass canopy growth are incorporated. - Modelled stomatal flux of ozone to productive grasslands in Europe shows different spatial and temporal variation to AOT40, and is modified by management and soil water status.

  9. MESOI Version 2.0: an interactive mesoscale Lagrangian puff dispersion model with deposition and decay

    International Nuclear Information System (INIS)

    Ramsdell, J.V.; Athey, G.F.; Glantz, C.S.

    1983-11-01

    MESOI Version 2.0 is an interactive Lagrangian puff model for estimating the transport, diffusion, deposition and decay of effluents released to the atmosphere. The model is capable of treating simultaneous releases from as many as four release points, which may be elevated or at ground-level. The puffs are advected by a horizontal wind field that is defined in three dimensions. The wind field may be adjusted for expected topographic effects. The concentration distribution within the puffs is initially assumed to be Gaussian in the horizontal and vertical. However, the vertical concentration distribution is modified by assuming reflection at the ground and the top of the atmospheric mixing layer. Material is deposited on the surface using a source depletion, dry deposition model and a washout coefficient model. The model also treats the decay of a primary effluent species and the ingrowth and decay of a single daughter species using a first order decay process. This report is divided into two parts. The first part discusses the theoretical and mathematical bases upon which MESOI Version 2.0 is based. The second part contains the MESOI computer code. The programs were written in the ANSI standard FORTRAN 77 and were developed on a VAX 11/780 computer. 43 references, 14 figures, 13 tables

  10. MESOI Version 2. 0: an interactive mesoscale Lagrangian puff dispersion model with deposition and decay

    Energy Technology Data Exchange (ETDEWEB)

    Ramsdell, J.V.; Athey, G.F.; Glantz, C.S.

    1983-11-01

    MESOI Version 2.0 is an interactive Lagrangian puff model for estimating the transport, diffusion, deposition and decay of effluents released to the atmosphere. The model is capable of treating simultaneous releases from as many as four release points, which may be elevated or at ground-level. The puffs are advected by a horizontal wind field that is defined in three dimensions. The wind field may be adjusted for expected topographic effects. The concentration distribution within the puffs is initially assumed to be Gaussian in the horizontal and vertical. However, the vertical concentration distribution is modified by assuming reflection at the ground and the top of the atmospheric mixing layer. Material is deposited on the surface using a source depletion, dry deposition model and a washout coefficient model. The model also treats the decay of a primary effluent species and the ingrowth and decay of a single daughter species using a first order decay process. This report is divided into two parts. The first part discusses the theoretical and mathematical bases upon which MESOI Version 2.0 is based. The second part contains the MESOI computer code. The programs were written in the ANSI standard FORTRAN 77 and were developed on a VAX 11/780 computer. 43 references, 14 figures, 13 tables.

  11. The metallogenic model of sandstone-type uranium deposits in interlayer oxidation zone in Yili basin

    International Nuclear Information System (INIS)

    Chen Daisheng; Wang Ruiying; Li Shengxiang; Zhang Kefang

    1997-08-01

    On the basis of comprehensive analysis on various sedimentary environmental criteria, the authors establish a depositional facies model of wet fan formed by alluvial fan's fast pouring into lake for the ore-bearing rocks, and point out favourable horizons and facies for the formation of uranium mineralizations. Deep researches are also done to uranium mineralization characteristics in interlayer oxidation zone, zonation features of ore bodies and spatial distribution regularities of uranium mineralizations. Three sets of data on ore-formation ages (19 Ma, 12 Ma, 1.0 Ma) are obtained with U-Pb isotope method. Various ore-controlling factors of the sandstone-type uranium mineralizations are expounded in detail. Ore-formation mechanism and metallogenic model of sandstone-type uranium deposit in the basin are summarized. Finally, the authors propose some detailed suggestions for the delimitation of prospective areas and future work in the basin, and emphasize that the southwest margin of the basin, especially the area between deposit No.511 and deposit No.512 should be a key prospecting area in the future. (4 refs., 6 figs., 3 tabs.)

  12. Radionuclides in fruit systems: Model-model intercomparison study

    Energy Technology Data Exchange (ETDEWEB)

    Linkov, I. [Cambridge Environmental, 58 Charles Street, Cambridge, MA 02141 (United States)]. E-mail: linkov@cambridgeenvironmental.com; Carini, F. [Universita Cattolica del Sacro Cuore, Faculty of Agricultural Sciences, Institute of Agricultural and Environmental Chemistry, Via Emilia Parmense, 84, I-29100 Piacenza (Italy); Collins, C. [T.H. Huxley School of Environment, Earth Sciences and Engineering (United Kingdom); Eged, K. [Department of Radiochemistry, University of Veszprem, P.O. Box 158 H-8201, H-8200 Veszprem (Hungary); Mitchell, N.G. [Mouchel Consulting Ltd., West Hall, Parvis Road, West Byfleet, Surrey, KT14 6EZ (United Kingdom); Mourlon, C. [Institute of Protection and Nuclear Safety (IPSN)/Division of Environmental Protection (DPRE), Laboratory of Environmental Modelling - LMODE, CE/Cadarache, 13 108 St Paul-lez-Durance Cedex (France); Ould-Dada, Z. [Food Standards Agency, Radiological Protection and Research Management Division, Aviation House, 125 Kingsway, Room 715B, London WC2B 6NH (United Kingdom); Robles, B. [CIEMAT, Dept. de Impacto Ambiental (DIAE), Edif. 3A, Avenida Complutense 22, E-28040 Madrid (Spain); Sweeck, L. [SCK.CEN, Boeretang 200, 2400 Mol (Belgium); Venter, A. [Enviros Consulting Ltd., Telegraphic House, Waterfront Quay, Salford Quays, Greater Manchester, M50 3XW (United Kingdom)

    2006-07-01

    Modeling is widely used to predict radionuclide distribution following accidental radionuclide releases. Modeling is crucial in emergency response planning and risk communication, and understanding model uncertainty is important not only in conducting analysis consistent with current regulatory guidance, but also in gaining stakeholder and decision-maker trust in the process and confidence in the results. However, while methods for dealing with parameter uncertainty are fairly well developed, an adequate representation of uncertainties associated with models remains rare. This paper addresses uncertainty about a model's structure (i.e., the relevance of simplifying assumptions and mathematical equations) that is seldom addressed in practical applications of environmental modeling. The use of several alternative models to derive a range of model outputs or risks is probably the only available technique to assess consistency in model prediction. Since each independent model requires significant resources for development and calibration, multiple models are not generally applied to the same problem. This study uses results from one such model intercomparison conducted by the Fruits Working Group, which was created under the International Atomic Energy Agency (IAEA) BIOMASS (BIOsphere Modelling and ASSessment) Program. Model-model intercomparisons presented in this study were conducted by the working group for two different scenarios (acute or continuous deposition), one radionuclide ({sup 137}Cs), and three fruit-bearing crops (strawberries, apples, and blackcurrants). The differences between models were as great as five orders of magnitude for short-term predictions following acute radionuclide deposition. For long-term predictions and for the continuous deposition scenario, the differences between models were about two orders of magnitude. The difference between strawberry, apple, and blackcurrant contamination predicted by one model is far less than the

  13. Radionuclides in fruit systems. Model-model intercomparison study

    Energy Technology Data Exchange (ETDEWEB)

    Linkov, I. [Cambridge Environmental, 58 Charles Street, Cambridge, MA 02141 (United States); Carini, F. [Universita Cattolica del Sacro Cuore, Faculty of Agricultural Sciences, Institute of Agricultural and Environmental Chemistry, Via Emilia Parmense, 84, I-29100 Piacenza (Italy); Collins, C. [T.H. Huxley School of Environment, Earth Sciences and Engineering (United Kingdom); Eged, K. [Department of Radiochemistry, University of Veszprem, P.O. Box 158 H-8201, H-8200 Veszprem (Hungary); Mitchell, N.G. [Mouchel Consulting Ltd., West Hall, Parvis Road, West Byfleet, Surrey, KT14 6EZ (United Kingdom); Mourlon, C. [Institute of Protection and Nuclear Safety IPSN, Division of Environmental Protection (DPRE), Laboratory of Environmental Modelling LMODE, CE/Cadarache, 13 108 St Paul-lez-Durance (France); Ould-Dada, Z. [Food Standards Agency, Radiological Protection and Research Management Division, Aviation House, 125 Kingsway, Room 715B, London WC2B 6NH (United Kingdom); Robles, B. [CIEMAT, Dept. de Impacto Ambiental (DIAE), Edif. 3A, Avenida Complutense 22, E-28040 Madrid (Spain); Sweeck, L. [SCK-CEN, Boeretang 200, 2400 Mol (Belgium); Venter, A. [Enviros Consulting Ltd., Telegraphic House, Waterfront Quay, Salford Quays, Greater Manchester, M50 3XW (United Kingdom)

    2006-07-01

    Modeling is widely used to predict radionuclide distribution following accidental radionuclide releases. Modeling is crucial in emergency response planning and risk communication, and understanding model uncertainty is important not only in conducting analysis consistent with current regulatory guidance, but also in gaining stakeholder and decision-maker trust in the process and confidence in the results. However, while methods for dealing with parameter uncertainty are fairly well developed, an adequate representation of uncertainties associated with models remains rare. This paper addresses uncertainty about a model's structure (i.e., the relevance of simplifying assumptions and mathematical equations) that is seldom addressed in practical applications of environmental modeling. The use of several alternative models to derive a range of model outputs or risks is probably the only available technique to assess consistency in model prediction. Since each independent model requires significant resources for development and calibration, multiple models are not generally applied to the same problem. This study uses results from one such model intercomparison conducted by the Fruits Working Group, which was created under the International Atomic Energy Agency (IAEA) BIOMASS (BIOsphere Modelling and ASSessment) Program. Model-model intercomparisons presented in this study were conducted by the working group for two different scenarios (acute or continuous deposition), one radionuclide ({sup 137}Cs), and three fruit-bearing crops (strawberries, apples, and blackcurrants). The differences between models were as great as five orders of magnitude for short-term predictions following acute radionuclide deposition. For long-term predictions and for the continuous deposition scenario, the differences between models were about two orders of magnitude. The difference between strawberry, apple, and blackcurrant contamination predicted by one model is far less than the

  14. Modelling impacts of atmospheric deposition and temperature on long-term DOC trends.

    Science.gov (United States)

    Sawicka, K; Rowe, E C; Evans, C D; Monteith, D T; E I Vanguelova; Wade, A J; J M Clark

    2017-02-01

    It is increasingly recognised that widespread and substantial increases in Dissolved organic carbon (DOC) concentrations in remote surface, and soil, waters in recent decades are linked to declining acid deposition. Effects of rising pH and declining ionic strength on DOC solubility have been proposed as potential dominant mechanisms. However, since DOC in these systems is derived mainly from recently-fixed carbon, and since organic matter decomposition rates are considered sensitive to temperature, uncertainty persists over the extent to which other drivers that could influence DOC production. Such potential drivers include fertilisation by nitrogen (N) and global warming. We therefore ran the dynamic soil chemistry model MADOC for a range of UK soils, for which time series data are available, to consider the likely relative importance of decreased deposition of sulphate and chloride, accumulation of reactive N, and higher temperatures, on soil DOC production in different soils. Modelled patterns of DOC change generally agreed favourably with measurements collated over 10-20years, but differed markedly between sites. While the acidifying effect of sulphur deposition appeared to be the predominant control on the observed soil water DOC trends in all the soils considered other than a blanket peat, the model suggested that over the long term, the effects of nitrogen deposition on N-limited soils may have been sufficient to raise the "acid recovery DOC baseline" significantly. In contrast, reductions in non-marine chloride deposition and effects of long term warming appeared to have been relatively unimportant. The suggestion that future DOC concentrations might exceed preindustrial levels as a consequence of nitrogen pollution has important implications for drinking water catchment management and the setting and pursuit of appropriate restoration targets, but findings still require validation from reliable centennial-scale proxy records, such as those being developed

  15. Modelling impacts of temperature, and acidifying and eutrophying deposition on DOC trends

    Science.gov (United States)

    Sawicka, Kasia; Rowe, Ed; Evans, Chris; Monteith, Don; Vanguelova, Elena; Wade, Andrew; Clark, Joanna

    2017-04-01

    Surface water dissolved organic carbon (DOC) concentrations in large parts of the northern hemisphere have risen over the past three decades, raising concern about enhanced contributions of carbon to the atmosphere and seas and oceans. The effect of declining acid deposition has been identified as a key control on DOC trends in soil and surface waters, since pH and ionic strength affect sorption and desorption of DOC. However, since DOC is derived mainly from recently-fixed carbon, and organic matter decomposition rates are considered sensitive to temperature, uncertainty persists regarding the extent to the relative importance of different drivers that affect these upward trends. We ran the dynamic model MADOC (Model of Acidity and Soil Organic Carbon) for a range of UK soils (podzols, gleysols and peatland), for which the time-series were available, to consider the likely relative importance of decreased deposition of sulphate and chloride, accumulation of reactive N, and higher temperatures, on DOC production in different soils. Modelled patterns of DOC change generally agreed favourably with measurements collated over 10-20 years, but differed markedly between sites. While the acidifying effect of sulphur deposition appeared to be the predominant control on the observed soil water DOC trends in all the soils considered other than a blanket peat, the model suggested that over the long term, the effects of nitrogen deposition on N-limited soils may have been sufficient to elevate the DOC recovery trajectory significantly. The second most influential cause of rising DOC in the model simulations was N deposition in ecosystems that are N-limited and respond with stimulated plant growth. Although non-marine chloride deposition made some contribution to acidification and recovery, it was not amongst the main drivers of DOC change. Warming had almost no effect on modelled historic DOC trends, but may prove to be a significant driver of DOC in future via its influence

  16. Comparison of Spheroidal Carbonaceous Particle Data with Modelled Atmospheric Black Carbon Concentration and Deposition and Air Mass Sources in Northern Europe, 1850–2010

    Directory of Open Access Journals (Sweden)

    Meri Ruppel

    2013-01-01

    Full Text Available Spheroidal carbonaceous particles (SCP are a well-defined fraction of black carbon (BC, produced only by the incomplete combustion of fossil fuels such as coal and oil. Their past concentrations have been studied using environmental archives, but, additionally, historical trends of BC concentration and deposition can be estimated by modelling. These models are based on BC emission inventories, but actual measurements of BC concentration and deposition play an essential role in their evaluation and validation. We use the chemistry transport model OsloCTM2 to model historical time series of BC concentration and deposition from energy and industrial sources and compare these to sedimentary measurements of SCPs obtained from lake sediments in Northern Europe from 1850 to 2010. To determine the origin of SCPs we generated back trajectories of air masses to the study sites. Generally, trends of SCP deposition and modelled results agree reasonably well, showing rapidly increasing values from 1950, to a peak in 1980, and a decrease towards the present. Empirical SCP data show differences in deposition magnitude between the sites that are not captured by the model but which may be explained by different air mass transport patterns. The results highlight the need for numerous observational records to reliably validate model results.

  17. Models of WO x films growth during pulsed laser deposition at elevated pressures of reactive gas

    Science.gov (United States)

    Gnedovets, A. G.; Fominski, V. Y.; Nevolin, V. N.; Romanov, R. I.; Fominski, D. V.; Soloviev, A. A.

    2017-12-01

    The films of tungsten oxides were prepared by pulsed laser ablation of W target in a reactive gas atmosphere (air of laboratory humidity). Optical analysis and ion signal measurements for the laser plume allowed to recognise a threshold gas pressure that suppresses the deposition of non-scattered atomic flux from the plume. When the pressure exceeds about 40 Pa, the films grow due to the deposition of species that could be formed in collisions of W atoms with reactive molecules (e.g., O2). Kinetic Monte Carlo method was used for modelling film growth. Comparison of the model structures with the experimentally prepared films has shown that the growth mechanism of ballistic deposition at a pressure of 40 Pa could be changed on the diffusion limited aggregation at a pressure of ~100 Pa. Thus, a cauliflower structure of the film transformed to a web-like structure. For good correlation of experimental and model structures of WO x , a dimension of structural elements in the model should coincide with W-O cluster size.

  18. Studies on methods and techniques of weak information extraction and integrated evaluation for sandstone-type uranium deposits

    International Nuclear Information System (INIS)

    Han Shaoyang; Ke Dan; Hou Huiqun; Hu Shuiqing

    2004-01-01

    Weak information extraction and integrated evaluation for sandstone-type uranium deposits are currently one of the important research contents in uranium exploration. Through several years researches, the authors put forward the meaning of aeromagnetic and aeroradioactive weak information extraction, study the formation theories of aeromagnetic and aeroradioactive weak information and establish effective mathematic models for weak information extraction. Based on GIS software, models of weak information extraction are actualized and the expert-grading model for integrated evaluation is developed. The trial of aeromagnetic and aeroradioactive weak information and integrated evaluation of uranium resources are completed by using GIS software in the study area. The researchful results prove that techniques of weak information extraction and integrated evaluation may further delineate the prospective areas of sandstone-type uranium deposits rapidly and improve the predicitive precision. (authors)

  19. 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.

  20. Towards a CFD-based mechanistic deposit formation model for straw-fired boilers

    DEFF Research Database (Denmark)

    Kær, Søren Knudsen; Rosendahl, Lasse Aistrup; Baxter, L.L.

    2006-01-01

    This paper discusses the application of FLUENTe in the analysis of grate-fired biomass boilers. A short description of the concept used to model fuel conversion on the grate and the coupling to the CFD code is offered. The development and implementation of a CFD-based deposition model is presented...... resistance changes. The model is applied to the straw-fired Masnedø boiler. Results are in good qualitative agreement with both measurements and observations at the plants. q 2005 Elsevier Ltd. All rights reserved....

  1. A comparative study of transfer factors of water, iodine and strontium on rye-grass and clover. Development of a model of evaluation of the limits of foliar contamination by wet deposit

    International Nuclear Information System (INIS)

    Angeletti, Livio; Levi, Emilio.

    1977-07-01

    Transfer factors of water, iodine ( 131 I) and strontium ( 85 Sr) on above-ground parts of rye-grass and clover were determined as a function of aspersion intensities. An analysis of the results showed the effect of aspersion intensities, nature of the chemical element and plant species on the values of transfer factors of iodine and strontium. It also made it possible to propose a simple method of evaluation of contamination limits of the aerial parts of plants by wet deposit, based on transfer values of water on plants only [fr

  2. Advanced Computational Modeling of Vapor Deposition in a High-Pressure Reactor

    Science.gov (United States)

    Cardelino, Beatriz H.; Moore, Craig E.; McCall, Sonya D.; Cardelino, Carlos A.; Dietz, Nikolaus; Bachmann, Klaus

    2004-01-01

    In search of novel approaches to produce new materials for electro-optic technologies, advances have been achieved in the development of computer models for vapor deposition reactors in space. Numerical simulations are invaluable tools for costly and difficult processes, such as those experiments designed for high pressures and microgravity conditions. Indium nitride is a candidate compound for high-speed laser and photo diodes for optical communication system, as well as for semiconductor lasers operating into the blue and ultraviolet regions. But InN and other nitride compounds exhibit large thermal decomposition at its optimum growth temperature. In addition, epitaxy at lower temperatures and subatmospheric pressures incorporates indium droplets into the InN films. However, surface stabilization data indicate that InN could be grown at 900 K in high nitrogen pressures, and microgravity could provide laminar flow conditions. Numerical models for chemical vapor deposition have been developed, coupling complex chemical kinetics with fluid dynamic properties.

  3. Estimation of aerial deposition and foliar uptake of xenobiotics: Assessment of current models

    Energy Technology Data Exchange (ETDEWEB)

    Link, S.O.; Fellows, R.J.; Cataldo, D.A.; Droppo, J.G.; Van Voris, P.

    1987-10-01

    This report reviews existing mathematical and/or computer simulation models that estimate xenobiotic deposition to and transport through (both curricular and stomatal) vegetative surfaces. The report evaluates the potential for coupling the best of those models to the existing Uptake, Translocation, Accumulation, and Biodegradation model to be used for future xenobiotic exposure assessments. Here xenobiotic compounds are defined as airborne contaminants, both organic and gaseous pollutants, that are introduced into the environment by man. Specifically this document provides a detailed review of the state-of-the-art models that addressed aerial deposition of particles and gases to foliage; foliar and cuticular transport, metabolism, and uptake of organic xenobiotics; and stomatal transport of gaseous and volatile organic xenobiotic pollutants. Where detailed information was available, parameters for each model are provided on a chemical by chemical as well as species by species basis. Sufficient detail is provided on each model to assess the potential for adapting or coupling the model to the existing UTAB plant exposure model. 126 refs., 6 figs., 10 tabs.

  4. Investigation on deposition condition, sedimentary environment and genesis of Mandan and Deh-Now bauxite deposits, Dehdasht area, Kohgiloye and Boyer-Ahmad province: using mineralogical studies

    Directory of Open Access Journals (Sweden)

    Alireza Zarasvandi

    2011-04-01

    Full Text Available The Mandan and Deh-Now bauxite deposits are located 40 km northeast of Dehdasht in Kohgiloye and Boyer-Ahmad province in the Zagros simply folded belt. The deposits were formed in the oldest rocks of the area of late Cretaceous age. The bauxite horizon is situated between Sarvak and Ilam formations. The aim of this study is to determine the mineralogy and texture relations of the deposits in order to determine the environment and status of bauxite mineralization. In this way, samples were selected from these bauxite deposits for mineralogical studies based on microscopic and XRD techniques. The bauxite horizon in the Mandan deposit consists of white, gray, black, pisolitic, red and yellow bauxites. The sequence was repeated in the Deh-Now without black and gray bauxites. Mineralogy is similar in all bauxitic layers and the main textures are pisolitic-ooide, ooide-spheroid, pisolitic, pelitomorphic and pseoudomorphic. Bohmite, diaspore, kaolinite and calcite are the most important minerals in both bauxitic layers of the Mandan and Deh-Now deposits. Due to bohmite mineralization in the study area, erosional and intense weathering environment in the Touronian-Cenomanian could be suggested for the deposition of bauxite in these deposits. Existence of interclasts in the pisolites and ooides indicate that these bauxites were transformed from the primary in situ environment to karstic sedimentary basin as authigenic origin. These studies indicate that there are two mineralized facies with different environmental status: (1 oxidation facies with bohmite, diaspore, kaolinite and hematite minerals and (2 reduced facies with pyrite, diaspore and chlorite mineralization. The lack of reduced condition at the Deh-Now deposit shows that the deposit formed only in oxidation status.

  5. Skin cell culture on an ear-shaped scaffold created by fused deposition modelling.

    Science.gov (United States)

    Cai, H; Azangwe, G; Shepherd, D E T

    2005-01-01

    Tissue engineering, where cells attach and grow on a scaffold, has the potential to produce replacement ears made from natural tissues and replace the need for rubber prosthetic ears. This study investigated the feasibility of using the rapid prototyping technique of Fused Deposition Modelling (FDM) to produce an ear-shaped scaffold. A three-dimensional image of the ear was used to manufacture ear-shaped scaffolds from ABS (acrylonitrile/butadiene/styrene) plastic using FDM. Human dermal fibroblasts were seeded on the scaffold (coated with fibronectin) to attach and grow in culture medium in an incubator for two weeks. Human keratinocytes were then seeded on to the fibroblast layer to attempt to produce a more realistic skin covering. The morphology of the cells were observed using scanning electron microscopy. The results show that a realistic ear-shaped scaffold can be made using FDM. Human fibroblasts were found to attach and grow. Human keratinocytes were successfully attached and grown on top of the fibroblasts and this resulted in a skin covering over the scaffold. This study shows that FDM has great potential as a manufacturing technique for ear-shaped scaffolds for tissue engineering.

  6. Numerical evaluation of ABS parts fabricated by fused deposition modeling and vapor smoothing

    Directory of Open Access Journals (Sweden)

    Sung-Uk Zhang

    2017-12-01

    Full Text Available The automotive industry has focused to use polymer materials in order to increase energy efficiency. So, the industry pays attention to use 3D printing technologies using several polymers. Among several 3D printer technologies, fused deposition modeling (FDM is one of the popular 3D printing technologies due to an inexpensive extrusion machine and multi-material printing. FDM could use thermoplastics such as ABS, PLA, ULTEM so on. However, it has a problem related to the post-processing because FDM has relatively poor layer resolution. In this study, the mechanical properties of ABS parts fabricated by FDM were measured. The ABS parts were divided into one with vapor smoothing process and the other without the vapor smoothing process which is one of the post-processing methods. Using dynamic mechanical analysis (DMA and dilatometer, temperature-dependent storage modulus and CTE for ABS specimens were measured. Based on the measured thermo-mechanical properties of ABS parts, finite element analysis was performed for an automotive bumper made of ABS. Moreover, response surface methodology was applied to study relationships among design parameters of thickness of the bumper, ambient temperature, and application of the vapor smoothing process. In result, a design guideline for a ABS product could be provided without time-consuming experiments

  7. Geodynamical model of development the gold ore deposit Muruntau in Central Kyzylkums /Western Uzbekistan/

    Science.gov (United States)

    Sidorova, I. P.

    2004-12-01

    Recent advances in geology and sciences dealing with planets resulted in ever-growing information on the internal structure and composition of upper and lower mantle and its role in the development of mineral deposits. Thus, the analysis of geologic-geophysical velocity sections on DSS-MOVZ profiles, that cross Central Kyzylkum, has revealed a number of features, which are characteristic of the upper mantle rocks, related to morphology of bodies, their physical properties, consisting mainly in their contrasting values for contiquous blocks, and general increased velocity and density of the rocks they contain. Petrologic-geophysical analysis of the same profiles proved the previous conclusions, and besides it allowed us to create the geodinamical model of development of a complicated continental lithosphere within Central Kyzylkum Ore Magmatic Concenter (CKOMC). CKOMC is a part of Western Uzbekistan's territory, that has maximum concentration of gold ore deposits of different scale, including the gigantic one- Muruntau. There are two main factors, that condition the area of the concenter: 1.Obduction of crust of the ocean to continental one during the Upper Paleozoic collision of Kyrgiz-Kazakh and Karakum-Tadjik microcontinents; 2.Geochemical gold specialization of Turkestan paleo-ocean's lithosphere. As a result of obduction of doubled, and sometimes even trebled crust of the ocean to continental, the front of rock granitization shifted to the sphere of ocean sediments development, and granite-gneiss layer of the continental crust went down to granulite zone. The latter factor provoked mass penetration of fluids from the former granite-gneiss and sedimentary-metamorphic layers, which due to their uprush to the surface, formed fluid-hydrothermal system , enriched with gold, in the new upper crust. This, in its turn, conditioned the formation of numerous gold ore deposits of different facies and formations observed in Central Kyzylkums. Abrupt increase in the crust

  8. Proceedings for a Workshop on Deposit Modeling, Mineral Resource Assessment, and Their Role in Sustainable Development

    Science.gov (United States)

    Briskey, Joseph A.; Schulz, Klaus J.

    2007-01-01

    The world's use of nonfuel mineral resources continues to increase to support a growing population and increasing standards of living. The ability to meet this increasing demand is affected especially by concerns about possible environmental degradation associated with minerals production and by competing land uses. What information does the world need to support global minerals development in a sustainable way?Informed planning and decisions concerning sustainability and future mineral resource supply require a long–term perspective and an integrated approach to resource, land use, economic, and environmental management worldwide. Such perspective and approach require unbiased information on the global distribution of identified and especially undiscovered resources, the economic and political factors influencing their development, and the potential environmental consequences of their exploitation.The U.S. Geological Survey and the former Deposit Modeling Program of the International Union of Geological Sciences (IUGS) of the United Nations Educational, Scientific and Cultural Organization (UNESCO) sponsored a workshop on "Deposit Modeling, Mineral Resource Assessment, and Their Role in Sustainable Development" at the 31st International Geological Congress (IGC) in Rio de Janeiro, Brazil, on August 18–19, 2000. The purpose of the workshop was to review the state-of-the-art in mineral deposit modeling and resource assessment and to examine the role of global assessments of nonfuel mineral resources in sustainable development.The workshop addressed questions such as the following: Which of the available mineral deposit models and assessment methods are best suited for predicting the locations, deposit types, and amounts of undiscovered nonfuel mineral resources remaining in the world? What is the availability of global geologic, mineral deposit, and mineral exploration information? How can mineral resource assessments be used to address economic and

  9. Modeling potential tsunami sources for deposits near Unalaska Island, Aleutian Islands

    Science.gov (United States)

    La Selle, S.; Gelfenbaum, G. R.

    2013-12-01

    In regions with little seismic data and short historical records of earthquakes, we can use preserved tsunami deposits and tsunami modeling to infer if, when and where tsunamigenic earthquakes have occurred. The Aleutian-Alaska subduction zone in the region offshore of Unalaska Island is one such region where the historical and paleo-seismicity is poorly understood. This section of the subduction zone is not thought to have ruptured historically in a large earthquake, leading some to designate the region as a seismic gap. By modeling various historical and synthetic earthquake sources, we investigate whether or not tsunamis that left deposits near Unalaska Island were generated by earthquakes rupturing through Unalaska Gap. Preliminary field investigations near the eastern end of Unalaska Island have identified paleotsunami deposits well above sea level, suggesting that multiple tsunamis in the last 5,000 years have flooded low-lying areas over 1 km inland. Other indicators of tsunami inundation, such as a breached cobble beach berm and driftwood logs stranded far inland, were tentatively attributed to the March 9, 1957 tsunami, which had reported runup of 13 to 22 meters on Umnak and Unimak Islands, to the west and east of Unalaska. In order to determine if tsunami inundation could have reached the runup markers observed on Unalaska, we modeled the 1957 tsunami using GeoCLAW, a numerical model that simulates tsunami generation, propagation, and inundation. The published rupture orientation and slip distribution for the MW 8.6, 1957 earthquake (Johnson et al., 1994) was used as the tsunami source, which delineates a 1200 km long rupture zone along the Aleutian trench from Delarof Island to Unimak Island. Model results indicate that runup and inundation from this particular source are too low to account for the runup markers observed in the field, because slip is concentrated in the western half of the rupture zone, far from Unalaska. To ascertain if any realistic

  10. Modeling of Temperature Field Evolution During Multilayered Direct Laser Metal Deposition

    Science.gov (United States)

    Zhang, DongYun; Feng, Zhe; Wang, ChengJie; Liu, Zhen; Dong, DongDong; Zhou, Yan; Wu, Rui

    2017-06-01

    It is of great importance to thoroughly explore the evolving temperature fields of direct laser metal deposition (abbreviated as LMD) in vertical thin wall manufacturing. It is helpful to control the temperature gradient, and even to adjust to forming microstructures and accumulation of residual stress. In this paper, a comprehensive three-dimensional transient model is developed for evolving temperature fields. The manufactured material is DS superalloy Rene80. The laser-powder interaction during the powder flowing process is simulated first, and its possible effect on the temperature field of the melting pool is analyzed. Then a 3D numerical simulation for the evolving temperature field is carried out based on considering transport phenomena during LMD such as the change in phase, powder injection and liquid flow. The applied deposition parameters are derived from experimental investigation with optimized vertical wall manufacturing. The simulated results explain why a balance between heat input and dissipation could form inside the vertical thin wall. These reconstruct the instability at an early phase of the building process without any temperature control unit and exhibit the influence of parameters such as laser power, deposition velocity and laser beam deposition pattern. The simulation results of temperature evolution are consistent with experimental investigation.

  11. A Bioeconomic Model of Cattle Stocking on Rangeland Threatened by Invasive Plants and Nitrogen Deposition

    OpenAIRE

    David Finnoff; Aaron Strong; John Tschirhart

    2008-01-01

    Across western North America, invasive plant species and elevated levels of nitrogen are threatening the productivity of rangelands. A bioeconomic model of stocking cattle on these rangelands is used to show that optimal stocking depends on the competition between native grasses and the invaders. However, nitrogen deposition is important in determining the ultimate rangeland species composition. Endogenous changes in plant successional thresholds are due to the interplay of nitrogen depositio...

  12. 3D Hatching: Linear halftoning for dual extrusion fused deposition modeling

    OpenAIRE

    Kuipers, Tim; Doubrovski, E.L.; Verlinden, J.C.

    2017-01-01

    This work presents halftoning techniques to manufacture 3D objects with the appearance of full grayscale imagery for Fused Deposition Modeling (FDM) printers. While droplet-based dithering is a common halftoning technique, this is not applicable to FDM printing, since FDM builds up objects by extruding material in semi-continuous paths. A set of three methods is presented which apply a linear halftoning principle called 'hatching' to horizontal, vertical and diagonal surfaces. These methods a...

  13. Comparative study of ice nucleating efficiency of K-feldspar in immersion and deposition freezing modes

    Science.gov (United States)

    Hiron, T.; Hoffmann, N.; Peckhaus, A.; Kiselev, A. A.; Leisner, T.; Flossmann, A. I.

    2016-12-01

    One of the main challenges in understanding the evolution of Earth's climate resides in the understanding the role of ice nucleation on the development of tropospheric clouds as well as its initiation. K-feldspar is known to be a very active ice nucleating particle and this study focuses on the characterization of its activity in two heterogeneous nucleation modes, immersion and deposition freezing.We use a newly built humidity-controlled cold stage allowing the simultaneous observation of up to 2000 identical 0.6-nanoliter droplets containing suspension of mineral dust particles. The droplets are first cooled down to observe immersion freezing, the obtained ice crystals are then evaporated and finally, the residual particles are exposed to the water vapor supersaturated with respect to ice.The ice nucleation abilities for the individual residual particles are then compared for the different freezing modes and correlation between immersion ice nuclei and deposition ice nuclei is investigated.Based on the electron microscopy analysis of the residual particles, we discuss the possible relationship between the ice nucleation properties of feldspar and its microstructure. Finally, we discuss the atmospheric implications of our experimental results, using DESCAM, a 1.5D bin-resolved microphysics model.

  14. Monte-Carlo study of energy deposition by heavy charged particles in sub-cellular volumes

    International Nuclear Information System (INIS)

    Emfietzoglou, D.; Papamichael, G.; Pathak, A.; Fotopoulos, A.; Nikjoo, H.

    2007-01-01

    Detailed-history Monte-Carlo code is used to study the energy deposition from proton and alpha particle tracks at the sub-cellular level. Inelastic cross sections for both the vapour and liquid phases of water have been implemented into the code in order to explore the influence of non-linear density effects associated with the condensed-phase cellular environment. Results of energy deposition and its straggling for 0.5 to 5 MeV amu -1 protons and alpha particles traversing or passing near spherical volumes of 2-200 nm in diameter relevant to DNA- and chromosome-size targets are presented. It is shown that the explicit account of δ-ray transport reduces the dose by as much as 10-60%, whereas stochastic fluctuations lead to a relative uncertainty ranging from 20% to more than 100%. Protons and alpha particles of the same velocity exhibit a similar δ-ray effect, whereas the relative uncertainty of the alphas is almost half that of protons. The effect of the phase is noticeable (10-15%) mainly through differences on the transport of δ-rays, which in liquid water have higher penetration distances. It is expected that the implementation of such results into multi-scale biophysical models of radiation effects will lead to a more realistic predictions on the efficacy of new radiotherapeutic modalities that employ either external proton beam irradiation or internal alpha-emitting radionuclides. (authors)

  15. Optimal Substrate Preheating Model for Thermal Spray Deposition of Thermosets onto Polymer Matrix Composites

    Science.gov (United States)

    Ivosevic, M.; Knight, R.; Kalidindi, S. R.; Palmese, G. R.; Tsurikov, A.; Sutter, J. K.

    2003-01-01

    High velocity oxy-fuel (HVOF) sprayed, functionally graded polyimide/WC-Co composite coatings on polymer matrix composites (PMC's) are being investigated for applications in turbine engine technologies. This requires that the polyimide, used as the matrix material, be fully crosslinked during deposition in order to maximize its engineering properties. The rapid heating and cooling nature of the HVOF spray process and the high heat flux through the coating into the substrate typically do not allow sufficient time at temperature for curing of the thermoset. It was hypothesized that external substrate preheating might enhance the deposition behavior and curing reaction during the thermal spraying of polyimide thermosets. A simple analytical process model for the deposition of thermosetting polyimide onto polymer matrix composites by HVOF thermal spray technology has been developed. The model incorporates various heat transfer mechanisms and enables surface temperature profiles of the coating to be simulated, primarily as a function of substrate preheating temperature. Four cases were modeled: (i) no substrate preheating; (ii) substrates electrically preheated from the rear; (iii) substrates preheated by hot air from the front face; and (iv) substrates electrically preheated from the rear and by hot air from the front.

  16. FALL3D: A computational model for transport and deposition of volcanic ash

    Science.gov (United States)

    Folch, A.; Costa, A.; Macedonio, G.

    2009-06-01

    FALL3D is a 3-D time-dependent Eulerian model for the transport and deposition of volcanic ashes and lapilli. The model solves the advection-diffusion-sedimentation (ADS) equation on a structured terrain-following grid using a second-order finite differences (FD) explicit scheme. Different parameterizations for the eddy diffusivity tensor and for the particle terminal settling velocities can be used. The code, written in FORTRAN 90, is available in both serial and parallel versions for Windows and Unix/Linux/Mac X operating systems (OS). A series of pre- and post-process utility programs and OS-dependent scripts to launch them are also included in the FALL3D distribution package. Although the model has been designed to forecast volcanic ash concentration in the atmosphere and ash loading at ground, it can also be used to model the transport of any kind of airborne solid particles. The model inputs are meteorological data, topography, grain-size distribution, shape and density of particles, and mass rate of particle injected into the atmosphere. Optionally, FALL3D can be coupled with the output of the meteorological processor CALMET, a diagnostic model which generates 3-D time-dependent zero-divergence wind fields from mesoscale forecasts incorporating local terrain effects. The FALL3D model can be a tool for short-term ash deposition forecasting and for volcanic fallout hazard assessment. As an example, an application to the 22 July 1998 Etna eruption is also presented.

  17. The Development and Validation of an In Vitro Airway Model to Assess Realistic Airway Deposition and Drug Permeation Behavior of Orally Inhaled Products Across Synthetic Membranes.

    Science.gov (United States)

    Huynh, Bao K; Traini, Daniela; Farkas, Dale R; Longest, P Worth; Hindle, Michael; Young, Paul M

    2018-04-01

    Current in vitro approaches to assess lung deposition, dissolution, and cellular transport behavior of orally inhaled products (OIPs) have relied on compendial impactors to collect drug particles that are likely to deposit in the airway; however, the main drawback with this approach is that these impactors do not reflect the airway and may not necessarily represent drug deposition behavior in vivo. The aim of this article is to describe the development and method validation of a novel hybrid in vitro approach to assess drug deposition and permeation behavior in a more representative airway model. The medium-sized Virginia Commonwealth University (VCU) mouth-throat (MT) and tracheal-bronchial (TB) realistic upper airway models were used in this study as representative models of the upper airway. The TB model was modified to accommodate two Snapwell ® inserts above the first TB airway bifurcation region to collect deposited nebulized ciprofloxacin-hydrochloride (CIP-HCL) droplets as a model drug aerosol system. Permeation characteristics of deposited nebulized CIP-HCL droplets were assessed across different synthetic membranes using the Snapwell test system. The Snapwell test system demonstrated reproducible and discriminatory drug permeation profiles for already dissolved and nebulized CIP-HCL droplets through a range of synthetic permeable membranes under different test conditions. The rate and extent of drug permeation depended on the permeable membrane material used, presence of a stirrer in the receptor compartment, and, most importantly, the drug collection method. This novel hybrid in vitro approach, which incorporates a modified version of a realistic upper airway model, coupled with the Snapwell test system holds great potential to evaluate postairway deposition characteristics, such as drug permeation and particle dissolution behavior of OIPs. Future studies will expand this approach using a cell culture-based setup instead of synthetic membranes, within a

  18. Numerical study on increasing mass flow ratio by energy deposition of high frequency pulsed laser

    International Nuclear Information System (INIS)

    Wang Diankai; Hong Yanji; Li Qian

    2013-01-01

    The mass flow ratio (MFR) of air breathing ramjet inlet would be decreased, when the Mach number is lower than the designed value. High frequency pulsed laser energy was deposited upstream of the cowl lip to reflect the stream so as to increase the MFR. When the Mach number of the flow was 5.0, and the static pressure and temperature of the flow were 2 551.6 Pa and 116.7 K, respectively, two-dimensional non-stationary compressible RANS equations were solved with upwind format to study the mechanisms of increasing MFR by high frequency pulsed laser energy deposition. The laser deposition frequency was 100 kHz and the average power was 500 W. The crossing point of the first forebody oblique shock and extension line of cowl lip was selected as the expected point. Then the deposition position was optimized by searching near the expected point. The results indicate that with the optimization of laser energy deposition position, the MFR would be increased from 63% to 97%. The potential value of increasing MFR by high frequency pulsed laser energy deposition was proved. The method for selection of the energy deposition position was also presented. (authors)

  19. Induction of complement proteins in a mouse model for cerebral microvascular Aβ deposition

    Directory of Open Access Journals (Sweden)

    DeFilippis Kelly

    2007-09-01

    Full Text Available Abstract The deposition of amyloid β-protein (Aβ in cerebral vasculature, known as cerebral amyloid angiopathy (CAA, is a common pathological feature of Alzheimer's disease and related disorders. In familial forms of CAA single mutations in the Aβ peptide have been linked to the increase of vascular Aβ deposits accompanied by a strong localized activation of glial cells and elevated expression of neuroinflammatory mediators including complement proteins. We have developed human amyloid-β precursor protein transgenic mice harboring two CAA Aβ mutations (Dutch E693Q and Iowa D694N that mimic the prevalent cerebral microvascular Aβ deposition observed in those patients, and the Swedish mutations (K670N/M671L to increase Aβ production. In these Tg-SwDI mice, we have reported predominant fibrillar Aβ along microvessels in the thalamic region and diffuse plaques in cortical region. Concurrently, activated microglia and reactive astrocytes have been detected primarily in association with fibrillar cerebral microvascular Aβ in this model. Here we show that three native complement components in classical and alternative complement pathways, C1q, C3, and C4, are elevated in Tg-SwDI mice in regions rich in fibrillar microvascular Aβ. Immunohistochemical staining of all three proteins was increased in thalamus, hippocampus, and subiculum, but not frontal cortex. Western blot analysis showed significant increases of all three proteins in the thalamic region (with hippocampus as well as the cortical region, except C3 that was below detection level in cortex. Also, in the thalamic region (with hippocampus, C1q and C3 mRNAs were significantly up-regulated. These complement proteins appeared to be expressed largely by activated microglial cells associated with the fibrillar microvascular Aβ deposits. Our findings demonstrate that Tg-SwDI mice exhibit elevated complement protein expression in response to fibrillar vascular Aβ deposition that is

  20. MEAD: an interdisciplinary study of the marine effects of atmospheric deposition in the Kattegat.

    Science.gov (United States)

    Spokes, L; Jickells, T; Weston, K; Gustafsson, B G; Johnsson, M; Liljebladh, B; Conley, D; Ambelas-Skjødth, C; Brandt, J; Carstensen, J; Christiansen, T; Frohn, L; Geernaert, G; Hertel, O; Jensen, B; Lundsgaard, C; Markager, S; Martinsen, W; Møller, B; Pedersen, B; Sauerberg, K; Sørensen, L L; Hasager, C C; Sempreviva, A M; Pryor, S C; Lund, S W; Larsen, S; Tjernström, M; Svensson, G; Zagar, M

    2006-04-01

    This paper summarises the results of the EU funded MEAD project, an interdisciplinary study of the effects of atmospheric nitrogen deposition on the Kattegat Sea between Denmark and Sweden. The study considers emissions of reactive nitrogen gases, their transport, transformations, deposition and effects on algal growth together with management options to reduce these effects. We conclude that atmospheric deposition is an important source of fixed nitrogen to the region particularly in summer, when nitrogen is the limiting nutrient for phytoplankton growth, and contributes to the overall eutrophication pressures in this region. However, we also conclude that it is unlikely that atmospheric deposition can, on its own, induce algal blooms in this region. A reduction of atmospheric nitrogen loads to this region will require strategies to reduce emissions of ammonia from local agriculture and Europe wide reductions in nitrous oxide emissions.

  1. Low temperature fused deposition modeling (FDM) 3D printing of thermolabile drugs.

    Science.gov (United States)

    Kollamaram, Gayathri; Croker, Denise M; Walker, Gavin M; Goyanes, Alvaro; Basit, Abdul W; Gaisford, Simon

    2018-04-26

    Fused deposition modelling (FDM) is the most commonly investigated 3D printing technology for the manufacture of personalized medicines, however, high temperatures associated with the process limit its wider application. The objective of this study was to print low-melting and thermolabile drugs by reducing the FDM printing temperature. Two immediate release polymers, Kollidon VA64 and Kollidon 12PF were investigated as potential candidates for low-temperature FDM printing. Ramipril was used as the model low melting temperature drug (109°C); to the authors' knowledge this is the lowest melting point drug investigated to date by FDM printing. Filaments loaded with 3% drug were obtained by hot melt extrusion at 70°C and ramipril printlets with a dose equivalent of 8.9 mg were printed at 90°C. HPLC analysis confirmed that the drug was stable with no signs of degradation and dissolution studies revealed that drug release from the printlets reached 100% within 20 to 30 mins. Variable temperature Raman and solid state nuclear magnetic resonance (SSNMR) spectroscopy techniques were used to evaluate drug stability over the processing temperature range. These data indicated that ramipril did not undergo degradation below its melting point (which is above the processing temperature range: 70-90 °C) but it was transformed into the impurity diketopiperazine upon exposure to temperatures higher than its melting point. The use of the excipients Kollidon VA64 and Kollidon 12PF in FDM was further validated by printing with the drug 4-aminosalicylic acid (4-ASA), which in previous work was reported to undergo degradation in FDM printing, but here it was found to be stable. This work demonstrates that the selection and use of new excipients can overcome one of the major disadvantages in FDM printing, drug degradation due thermal heating, making this technology suitable for drugs with lower melting temperatures. Copyright © 2018. Published by Elsevier B.V.

  2. Performance evaluation of paper embossing tools produced by fused deposition modelling additive manufacturing technology

    Directory of Open Access Journals (Sweden)

    Gordana Delić

    2017-12-01

    Full Text Available From its beginnings, up to a few years ago, additive manufacturing technology was able to produce models or prototypes which have limited use, because of materials mechanical properties. With advancement and invention of new materials, this is changing. Now, it is possible to create 3D prints that can be used as final products or functional tools, using technology and materials with low environmental impact. The goal of this study was to examine opportunities for production of paper embossing tools by fused deposition modelling (FDM 3D printing. This study emphasises the use of environmentally friendly poly-lactic acid (PLA materials in FDM technology, contrary to the conventional method using metal alloys and acids. Embossing of line elements and letters using 3D printed embossing tools was done on six different types of paper. Embossing force was applied using SHIMADZU EZ-LX Compact Tabletop Testing Machine. Each type of paper was repeatedly embossed using different values of embossing force (in 250 N increments, starting at 1000 N to determine the optimal embossing force for each specific paper type. When determined, the optimal embossing force was used on ten samples for each paper type. Results of embossing were analysed and evaluated. The analysis consisted of investigating the effects of the applied embossing force and characteristics such as paper basis weight, paper structure, surface characteristic and fibre direction of the paper. Results show that paper characteristics determine the embossing force required for achieving a good embossing result. This means that with the right amount of embossing force, letters and borderlines can be equally well formed by the embossing process regardless of paper weight, surface characteristics, etc. Embossing tools produced in this manner can be used in case of the embossing elements that are not complex. The reason for this is the limitation of FDM technology and lack of precision needed for fine

  3. Palaeomagnetic dating method accounting for post-depositional remanence and its application to geomagnetic field modelling

    Science.gov (United States)

    Nilsson, A.; Suttie, N.

    2016-12-01

    Sedimentary palaeomagnetic data may exhibit some degree of smoothing of the recorded field due to the gradual processes by which the magnetic signal is `locked-in' over time. Here we present a new Bayesian method to construct age-depth models based on palaeomagnetic data, taking into account and correcting for potential lock-in delay. The age-depth model is built on the widely used "Bacon" dating software by Blaauw and Christen (2011, Bayesian Analysis 6, 457-474) and is designed to combine both radiocarbon and palaeomagnetic measurements. To our knowledge, this is the first palaeomagnetic dating method that addresses the potential problems related post-depositional remanent magnetisation acquisition in age-depth modelling. Age-depth models, including site specific lock-in depth and lock-in filter function, produced with this method are shown to be consistent with independent results based on radiocarbon wiggle match dated sediment sections. Besides its primary use as a dating tool, our new method can also be used specifically to identify the most likely lock-in parameters for a specific record. We explore the potential to use these results to construct high-resolution geomagnetic field models based on sedimentary palaeomagnetic data, adjusting for smoothing induced by post-depositional remanent magnetisation acquisition. Potentially, this technique could enable reconstructions of Holocene geomagnetic field with the same amplitude of variability observed in archaeomagnetic field models for the past three millennia.

  4. Integrated geophysical imaging of a concealed mineral deposit: a case study of the world-class Pebble porphyry deposit in southwestern Alaska

    Science.gov (United States)

    Shah, Anjana K.; Bedrosian, Paul A.; Anderson, Eric D.; Kelley, Karen D.; Lang, James

    2013-01-01

    We combined aeromagnetic, induced polarization, magnetotelluric, and gravity surveys as well as drillhole geologic, alteration, magnetic susceptibility, and density data for exploration and characterization of the Cu-Au-Mo Pebble porphyry deposit. This undeveloped deposit is almost completely concealed by postmineralization sedimentary and volcanic rocks, presenting an exploration challenge. Individual geophysical methods primarily assist regional characterization. Positive chargeability and conductivity anomalies are observed over a broad region surrounding the deposit, likely representing sulfide minerals that accumulated during multiple stages of hydrothermal alteration. The mineralized area occupies only a small part of the chargeability anomaly because sulfide precipitation was not unique to the deposit, and mafic rocks also exhibit strong chargeability. Conductivity anomalies similarly reflect widespread sulfides as well as water-saturated glacial sediments. Mineralogical and magnetic susceptibility data indicate magnetite destruction primarily within the Cu-Au-Mo mineralized area. The magnetic field does not show a corresponding anomaly low but the analytic signal does in areas where the deposit is not covered by postmineralization igneous rocks. The analytic signal shows similar lows over sedimentary rocks outside of the mineralized area, however, and cannot uniquely distinguish the deposit. We find that the intersection of positive chargeability anomalies with analytic signal lows, indicating elevated sulfide concentrations but low magnetite at shallow depths, roughly delineates the deposit where it is covered only by glacial sediments. Neither chargeability highs nor analytic signal lows are present where the deposit is covered by several hundred meters of sedimentary and volcanic rocks, but a 3D resistivity model derived from magnetotelluric data shows a corresponding zone of higher conductivity. Gravity data highlight geologic features within the

  5. Toward an integrated genetic model for vent-distal SEDEX deposits

    Science.gov (United States)

    Sangster, D. F.

    2018-04-01

    Although genetic models have been proposed for vent-proximal SEDEX deposits, an equivalent model for vent-distal deposits has not yet appeared. In view of this, it is the object of this paper to present a preliminary integrated vent-distal genetic model through exploration of four major components: (i) nature of the ore-forming fluid, (ii) role of density of the unconsolidated host sediments, (iii) dynamics of sulfate reduction and (iv) depositional environment. Two sub-groups of SEDEX Pb-Zn deposits, vent-proximal and vent-distal, are widely recognized today. Of the two, the latter is by far the largest in terms of metal content with each of the 13 largest containing in excess of 7.5 M (Zn+Pb) metal. In contrast, only one vent-proximal deposit (Sullivan) falls within this size range. Vent-proximal deposits are characteristically underlain by local networks of sulfide-filled veins (commonly regarded as feeder veins) surrounded by a discordant complex of host rock alteration. These attributes are missing in vent-distal deposits, which has led to the widespread view that vent-distal ore-forming fluids have migrated unknown distances away from their vent sites. Because of the characteristic fine grain size of ore minerals, critical fluid inclusion data are lacking for vent-distal ore-stage sulfides. Consequently, hypothetical fluids such as those which formed MVT deposits (120 °C, 20% NaCl equiv.) are considered to represent vent-distal fluids as well. Such high-salinity fluids are capable of carrying significant concentrations of Pb and Zn as chloride complexes whil