WorldWideScience

Sample records for deposition models volume

  1. U3O8 production cost analysis study. Sandstone deposit mine model EA-730, Volume 1

    International Nuclear Information System (INIS)

    1978-08-01

    Objective was the development and testing of a model for estimating the production cost of conventional uranium mining. The model used evolved from a base case underground mine of 1000 tons per day output at a nominal depth of 900 feet, and from base-case open pit mines of 2000 tons per day output at 30-, 120-, and 240-foot depths. In addition, an alternate production method employing heap leaching was partially investigated, to be merged with similar work performed by another contractor. The model was internally structured into component submodels capable of reflecting the contributory factors which aggregate into the computed production cost. A financial submodel based on last-quarter 1976 prices used conventional accounting practices to generate a cash flow and profit-and-loss record over the mine life. From this a selling price was obtained based on a desired discounted cash flow return on equity. This submodel is also capable of accepting input inflation rates so that costs in current dollars for future years can be estimated. A Monte Carlo method of the analysis of variance was applied to 50 model runs to obtain a statistical estimate for the expected variance in production cost

  2. 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...

  3. Modeled Wet Nitrate Deposition

    Data.gov (United States)

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

  4. Anisotropy and humidity effect on tensile properties and electrical volume resistivity of fused deposition modeled acrylonitrile butadiene styrene composites

    OpenAIRE

    Almenara Cueto, Carlos Ignacio

    2017-01-01

    En la presente tesis, se estudió la influencia de la anisotropía y la humedad en las propiedades mecánicas a la tracción y la resistividad volumétrica de los compuestos de Acrilonitrilo Butadieno Estireno reforzado con Nano Tubos de Carbono y Acrilonitrilo Butadieno Estireno reforzado con Micro Fibras de Carbono impresos en 3D de por Deposición de Material Fundido. Para estudiar la influencia de la anisotropía, tres diferentes orientaciones de impresión de capa fueron compar...

  5. 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

  6. A radon progeny deposition model

    International Nuclear Information System (INIS)

    Rielage, Keith; Elliott, Steven R.; Hime, Andrew; Guiseppe, Vincent E.; Westerdale, S.

    2010-01-01

    The next generation low-background detectors operating underground aim for unprecedented low levels of radioactive backgrounds. Although the radioactive decays of airborne radon (particularly 222 Rn) and its subsequent progeny present in an experiment are potential backgrounds, also problematic is the deposition of radon progeny on detector materials. Exposure to radon at any stage of assembly of an experiment can result in surface contamination by progeny supported by the long half life (22 y) of 210 Pb on sensitive locations of a detector. An understanding of the potential surface contamination from deposition will enable requirements of radon-reduced air and clean room environments for the assembly of low background experiments. It is known that there are a number of environmental factors that govern the deposition of progeny onto surfaces. However, existing models have not explored the impact of some environmental factors important for low background experiments. A test stand has been constructed to deposit radon progeny on various surfaces under a controlled environment in order to develop a deposition model. Results from this test stand and the resulting deposition model are presented.

  7. A Radon Progeny Deposition Model

    International Nuclear Information System (INIS)

    Guiseppe, V. E.; Elliott, S. R.; Hime, A.; Rielage, K.; Westerdale, S.

    2011-01-01

    The next generation low-background detectors operating underground aim for unprecedented low levels of radioactive backgrounds. Although the radioactive decays of airborne radon (particularly 222 Rn) and its subsequent progeny present in an experiment are potential backgrounds, also problematic is the deposition of radon progeny on detector materials. Exposure to radon at any stage of assembly of an experiment can result in surface contamination by progeny supported by the long half life (22 y) of 210 Pb on sensitive locations of a detector. An understanding of the potential surface contamination from deposition will enable requirements of radon-reduced air and clean room environments for the assembly of low background experiments. It is known that there are a number of environmental factors that govern the deposition of progeny onto surfaces. However, existing models have not explored the impact of some environmental factors important for low background experiments. A test stand has been constructed to deposit radon progeny on various surfaces under a controlled environment in order to develop a deposition model. Results from this test stand and the resulting deposition model are presented.

  8. Lagrangian-similarity diffusion-deposition model

    International Nuclear Information System (INIS)

    Horst, T.W.

    1979-01-01

    A Lagrangian-similarity diffusion model has been incorporated into the surface-depletion deposition model. This model predicts vertical concentration profiles far downwind of the source that agree with those of a one-dimensional gradient-transfer model

  9. Arc-related porphyry molybdenum deposit model: Chapter D in Mineral deposit models for resource assessment

    Science.gov (United States)

    Taylor, Ryan D.; Hammarstrom, Jane M.; Piatak, Nadine M.; Seal, Robert R.

    2012-01-01

    This report provides a descriptive model for arc-related porphyry molybdenum deposits. Presented within are geological, geochemical, and mineralogical characteristics that differentiate this deposit type from porphyry copper and alkali-feldspar rhyolite-granite porphyry molybdenum deposits. The U.S. Geological Survey's effort to update existing mineral deposit models spurred this research, which is intended to supplement previously published models for this deposit type that help guide mineral-resource and mineral-environmental assessments.

  10. A Hierarchical Agency Model of Deposit Insurance

    OpenAIRE

    Jonathan Carroll; Shino Takayama

    2010-01-01

    This paper develops a hierarchical agency model of deposit insurance. The main purpose is to undertake a game theoretic analysis of the consequences of deposit insurance schemes and their effects on monitoring incentives for banks. Using this simple framework, we analyze both risk- independent and risk-dependent premium schemes along with reserve requirement constraints. The results provide policymakers with not only a better understanding of the effects of deposit insurance on welfare and th...

  11. 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

  12. Integrated prospecting model in Jinguanchong uranium deposit

    International Nuclear Information System (INIS)

    Xie Yongjian

    2006-01-01

    Jinguanchong uranium deposit is large in scale, which brings difficulties to prospecting and researches. Based on conditions of mineral-formation, geophysics and geochemistry, this paper summarizes a few geophysical and geochemical prospecting methods applied to this deposit. The principles, characteristics, application condition and exploration phases of these prospecting methods are discussed and some prospecting examples are also given in the prospecting for Jinguanchong uranium deposit. Based on summarizing the practice and effects of different methods such as gamma and electromagnetic method, soil emanation prospecting, track etch technique and polonium method used in uranium prospecting, the author finally puts forward a primary uranium prospecting model for the further prospecting in Jinguanchong uranium deposit through combining the author's experience with practice. (authors)

  13. Crud deposition modeling on BWR fuel rods

    International Nuclear Information System (INIS)

    Kucuk, Aylin; Cheng, Bo; Potts, Gerald A.; Shiralkar, Bharat; Morgan, Dave; Epperson, Kenny; Gose, Garry

    2014-01-01

    Deposition of boiling water reactor (BWR) system corrosion products (crud) on operating fuel rods has resulted in performance-limiting conditions in a number of plants. The operational impact of performance-limiting conditions involving crud deposition can be detrimental to a BWR operator, resulting in unplanned or increased frequency of fuel inspections, fuel failure and associated radiological consequences, operational restrictions including core power derate and/or forced shutdowns to remove failed fuel, premature discharge of individual bundles or entire reloads, and/or undesirable core design restrictions. To facilitate improved management of crud-related fuel performance risks, EPRI has developed the CORAL (Crud DepOsition Risk Assessment ModeL) tool. This paper presents a summary of the CORAL elements and benchmarking results. Applications of CORAL as a tool for fuel performance risk assessment are also discussed. (author)

  14. 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)

  15. 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

  16. Facts and fallacies in wet deposition modelling

    International Nuclear Information System (INIS)

    ApSimon, H.M.; Goddard, A.J.H.; Manning, P.M.; Simms, K.

    1987-01-01

    Following a reactor accident, relatively high contamination at ground level can occur, even at quite long distances from the source, if the pollutant cloud encounters intense precipitation. To estimate such contamination and its extent properly, it is necessary to take into account the spatial and temporal structure of rain patterns and their motion. Currently, models of wet deposition are rather crude. Source meteorology is usually used and is clearly inadequate. Furthermore, no allowance is made for the dynamic nature of rainfall, which occurs as a result of vertical air motions and convergence; nor for the different scavenging mechanism operating in and below cloud. Meteorological information available on these aspects of wet deposition is reviewed, and their importance and inclusion in modelling and prediction of resulting ground contamination is indicated. Some of the pitfalls of simple modelling procedures are illustrated. (author)

  17. 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)

  18. 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)

  19. Probabilistic accident consequence uncertainty analysis -- Uncertainty assessment for deposited material and external doses. Volume 2: Appendices

    Energy Technology Data Exchange (ETDEWEB)

    Goossens, L.H.J.; Kraan, B.C.P.; Cooke, R.M. [Delft Univ. of Technology (Netherlands); Boardman, J. [AEA Technology (United Kingdom); Jones, J.A. [National Radiological Protection Board (United Kingdom); Harper, F.T.; Young, M.L. [Sandia National Labs., Albuquerque, NM (United States); Hora, S.C. [Univ. of Hawaii, Hilo, HI (United States)

    1997-12-01

    The development of two new probabilistic accident consequence codes, MACCS and COSYMA, was completed in 1990. These codes estimate the consequence from the accidental releases of radiological material from hypothesized accidents at nuclear installations. In 1991, the US Nuclear Regulatory Commission and the Commission of the European Communities began cosponsoring a joint uncertainty analysis of the two codes. The ultimate objective of this joint effort was to systematically develop credible and traceable uncertainty distributions for the respective code input variables. A formal expert judgment elicitation and evaluation process was identified as the best technology available for developing a library of uncertainty distributions for these consequence parameters. This report focuses on the results of the study to develop distribution for variables related to the MACCS and COSYMA deposited material and external dose models. This volume contains appendices that include (1) a summary of the MACCS and COSYMA consequence codes, (2) the elicitation questionnaires and case structures, (3) the rationales and results for the panel on deposited material and external doses, (4) short biographies of the experts, and (5) the aggregated results of their responses.

  20. 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

  1. 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....

  2. A MULTILAYER BIOCHEMICAL DRY DEPOSITION MODEL 1. MODEL FORMULATION

    Science.gov (United States)

    A multilayer biochemical dry deposition model has been developed based on the NOAA Multilayer Model (MLM) to study gaseous exchanges between the soil, plants, and the atmosphere. Most of the parameterizations and submodels have been updated or replaced. The numerical integration ...

  3. A MULTILAYER BIOCHEMICAL DRY DEPOSITION MODEL 2. MODEL EVALUATION

    Science.gov (United States)

    The multilayer biochemical dry deposition model (MLBC) described in the accompanying paper was tested against half-hourly eddy correlation data from six field sites under a wide range of climate conditions with various plant types. Modeled CO2, O3, SO2<...

  4. 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...

  5. PRISM -- A tool for modelling proton energy deposition in semiconductor materials

    International Nuclear Information System (INIS)

    Oldfield, M.K.; Underwood, C.I.

    1996-01-01

    This paper presents a description of, and test results from, a new PC based software simulation tool PRISM (Protons in Semiconductor Materials). The model describes proton energy deposition in complex 3D sensitive volumes of semiconductor materials. PRISM is suitable for simulating energy deposition in surface-barrier detectors and semiconductor memory devices, the latter being susceptible to Single-Event Upset (SEU) and Multiple-Bit Upset (MBU). The design methodology on which PRISM is based, together with the techniques used to simulate ion transport and energy deposition, are described. Preliminary test results used to analyze the PRISM model are presented

  6. FURTHER STUDIES ON THE VARIATION OF SPRAY DEPOSITS IN VINEYARDS WITH AIRFLOW RATE AND VOLUME RATE

    Directory of Open Access Journals (Sweden)

    Emanuele Cerruto

    2007-03-01

    Full Text Available The present research, continuing that reported in [2], deals with the spray application subject, so to investigate as volume rate and airflow rate, forward speed being equal, affect the foliar deposition in an espalier vineyard. Experimental trials were carried out by means of an air assisted towed sprayer, equipped with “Albuz ATR” nozzles. To take into account the influence of the development of the trees, the field trials were replicated in two phenological stages with an interval of about one month: “Inflorescences fully developed” (stage 1 and “Beginning of berry touch” (stage 2. A full factorial experiment was carried out for each growth stage, with two airflow rates (3.9 and 7.5 m3/s, three volume rates (103, 216, and 276 L/ha in the first growth stage and 154, 330 and 432 L/ha in the second growth stage, and four replicates, arranged according to a randomised complete block design. Working pressure (1.2 MPa and forward speed (1.4 m/s were kept unchanged for all the trials. The foliar deposition was measured by means of a spectrophotometric technique. The leaves were sampled on two depth layers and two or three heights, according to the trees’ development. The results showed that volume rate did not significantly influence the mean foliar deposition in both the two growth stages, while the highest deposits were obtained with the lowest airflow rate. The airflow rate × volume rate interaction, though not statistically significant, showed that low volume rates together with high airflow rates, result in a noticeable reduction in foliar deposition (29% with respect the grand mean, due to an increase of the spry drift, especially at the first growth stage, when the foliar development is little. These second tests, unlike those described in [2], did not show any positive influence of the airflow rate on the foliar deposition in the inner part of the canopy, so further investigations could be necessary to better understand the

  7. 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)

  8. 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.

  9. 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.

  10. Probabilistic accident consequence uncertainty analysis: Dispersion and deposition uncertainty assessment. Volume 3, Appendices C, D, E, F, and G

    Energy Technology Data Exchange (ETDEWEB)

    Harper, F.T.; Young, M.L.; Miller, L.A. [Sandia National Labs., Albuquerque, NM (United States)] [and others

    1995-01-01

    The development of two new probabilistic accident consequence codes, MACCS and COSYMA, completed in 1990, estimate the risks presented by nuclear installations based on postulated frequencies and magnitudes of potential accidents. In 1991, the US Nuclear Regulatory Commission (NRC) and the Commission of the European Communities (CEC) began a joint uncertainty analysis of the two codes. The objective was to develop credible and traceable uncertainty distributions for the input variables of the codes. Expert elicitation, developed independently, was identified as the best technology available for developing a library of uncertainty distributions for the selected consequence parameters. The study was formulated jointly and was limited to the current code models and to physical quantities that could be measured in experiments. To validate the distributions generated for the wet deposition input variables, samples were taken from these distributions and propagated through the wet deposition code model along with the Gaussian plume model (GPM) implemented in the MACCS and COSYMA codes. Resulting distributions closely replicated the aggregated elicited wet deposition distributions. Project teams from the NRC and CEC cooperated successfully to develop and implement a unified process for the elaboration of uncertainty distributions on consequence code input parameters. Formal expert judgment elicitation proved valuable for synthesizing the best available information. Distributions on measurable atmospheric dispersion and deposition parameters were successfully elicited from experts involved in the many phenomenological areas of consequence analysis. This volume is the third of a three-volume document describing the project and contains descriptions of the probability assessment principles; the expert identification and selection process; the weighting methods used; the inverse modeling methods; case structures; and summaries of the consequence codes.

  11. Probabilistic accident consequence uncertainty analysis: Dispersion and deposition uncertainty assessment. Volume 3, Appendices C, D, E, F, and G

    International Nuclear Information System (INIS)

    Harper, F.T.; Young, M.L.; Miller, L.A.

    1995-01-01

    The development of two new probabilistic accident consequence codes, MACCS and COSYMA, completed in 1990, estimate the risks presented by nuclear installations based on postulated frequencies and magnitudes of potential accidents. In 1991, the US Nuclear Regulatory Commission (NRC) and the Commission of the European Communities (CEC) began a joint uncertainty analysis of the two codes. The objective was to develop credible and traceable uncertainty distributions for the input variables of the codes. Expert elicitation, developed independently, was identified as the best technology available for developing a library of uncertainty distributions for the selected consequence parameters. The study was formulated jointly and was limited to the current code models and to physical quantities that could be measured in experiments. To validate the distributions generated for the wet deposition input variables, samples were taken from these distributions and propagated through the wet deposition code model along with the Gaussian plume model (GPM) implemented in the MACCS and COSYMA codes. Resulting distributions closely replicated the aggregated elicited wet deposition distributions. Project teams from the NRC and CEC cooperated successfully to develop and implement a unified process for the elaboration of uncertainty distributions on consequence code input parameters. Formal expert judgment elicitation proved valuable for synthesizing the best available information. Distributions on measurable atmospheric dispersion and deposition parameters were successfully elicited from experts involved in the many phenomenological areas of consequence analysis. This volume is the third of a three-volume document describing the project and contains descriptions of the probability assessment principles; the expert identification and selection process; the weighting methods used; the inverse modeling methods; case structures; and summaries of the consequence codes

  12. International Nuclear Model. Volume 3. Program description

    International Nuclear Information System (INIS)

    Andress, D.

    1985-01-01

    This is Volume 3 of three volumes of documentation of the International Nuclear Model (INM). This volume presents the Program Description of the International Nuclear Model, which was developed for the Nuclear and Alternate Fuels Division (NAFD), Office of Coal, Nuclear, Electric and Alternate Fuels, Energy Information Administration (EIA), US Department of Energy (DOE). The International Nuclear Model (INM) is a comprehensive model of the commercial nuclear power industry. It simulates economic decisions for reactor deployment and fuel management decision based on an input set of technical economic and scenario parameters. The technical parameters include reactor operating characteristics, fuel cycle timing and mass loss factors, and enrichment tails assays. Economic parameters include fuel cycle costs, financial data, and tax alternatives. INM has a broad range of scenario options covering, for example, process constraints, interregional activities, reprocessing, and fuel management selection. INM reports reactor deployment schedules, electricity generation, and fuel cycle requirements and costs. It also has specialized reports for extended burnup and permanent disposal. Companion volumes to Volume 3 are: Volume 1 - Model Overview, and Volume 2 - Data Base Relationships

  13. 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.

  14. Computational Model for Spacecraft/Habitat Volume

    Data.gov (United States)

    National Aeronautics and Space Administration — Please note that funding to Dr. Simon Hsiang, a critical co-investigator for the development of the Spacecraft Optimization Layout and Volume (SOLV) model, was...

  15. Development of a Guinea Pig Lung Deposition Model

    Science.gov (United States)

    2016-01-01

    Development of a Guinea Pig Lung Deposition Model Distribution Statement A. Approved for public release; distribution is unlimited. January...4 Figure 2. Particle deposition in the lung of the guinea pig via endotracheal breathing...Particle deposition in the lungs of guinea pigs via nasal breathing. ......................................... 12 v PREFACE The research work

  16. 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

  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. An earth system model for evaluation of dry deposition

    Energy Technology Data Exchange (ETDEWEB)

    Arritt, R.W. [Iowa State Univ., Ames, IA (United States)

    1994-12-31

    A coupled model of atmosphere, soil, and vegetation showed that interactions among the various components can have important effects on dry deposition of SO{sub 2}. In particular, dry soil (near or below the wilting point) leads to an increase of stomatal resistance and a decrease in deposition. Once the soil moisture is at least twice the wilting point, the model results indicate that additional moisture has little effect on the accumulated daytime dry deposition.

  19. 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.

  20. Acidic precipitation. Volume 3: Sources, deposition, and canopy interactions. Advances in environmental science

    Energy Technology Data Exchange (ETDEWEB)

    Lindberg, S.E.; Page, A.L.; Norton, S.A. (eds.)

    1990-01-01

    As has been the case with many environmental issues of the twentieth century, acidic precipitation has its origin in emissions to the atmosphere of numerous compounds from both natural and man-made sources. This volume emphasizes the atmospheric aspects of acidic precipitation and all that this term has come to include (e.g. toxic gases such as ozone, trace metals, aluminum, and oxides of nitrogen). It progresses from emissions of the precursors of acidic precipitation to their eventual deposition on environmental surfaces. The chapters describe the sources of acidic and basic airborne substances, their interactions in the atmosphere and with rain droplets, and their reactions with other airborne constituents such as aluminum and other metals. Also discussed are the use of metals as tracers of sources of the precursors of acidic precipitation and as tracers of historical deposition rates, the processes controlling the removal of airborne material as dry deposition and deposition interactions with the forest canopy, and past and future trends in atmospheric emissions and options for their abatement.

  1. Characterization of space radiation environment in terms of the energy deposition in functionally important volumes

    International Nuclear Information System (INIS)

    Braby, L.A.; Metting, N.F.; Wilson, W.E.; Ratcliffe, C.A.

    1988-01-01

    Since the damage which initiates detrimental effects occurs in a small site (semiconductor junctions, or biological cell nuclei), these differences in spatial distribution of ionization maybe the relevant factor controlling the effectiveness of different radiations. Again, when the appropriate cross section data are available Monte Carlo methods can be used to simulate the positions of all ionizations and excitations produced by a typical charged particle. This calculated track structure must interact with the biological or electronic entity in which it occurs to produce the effect. However, we do not know the mechanisms of this interaction and thus cannot specify which characteristics of the charged particle track are responsible for the relevant damage. From track structure we can obtain the spectrum of energy deposition in small volumes which may be relevant to the processes of concern. This has lead to a new approach to dosimetry, one which emphasizes the stochastic nature of energy deposition in small sites, known as microdosimetry. 6 refs., 4 figs

  2. 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

  3. Modeling the economics of LLW volume reduction

    International Nuclear Information System (INIS)

    Voth, M.H.; Witzig, W.F.

    1986-01-01

    Generators of low-level (radioactive) waste (LLW) are under pressure to implement volume reduction (VR) programs for political and economic reasons. Political reasons include the appearance of generating less waste or meeting quotas. Economic reasons include avoiding high disposal costs and associated surcharges. Volume reduction results in less total volume over which fixed disposal costs are allocated and therefore higher unit costs for disposal. As numerous small compacts are developed, this often overlooked effect becomes more pronounced. The described model presents two unique significant features. First, a feedback loop considers the impact of VR on disposal rates, and second, it appeals to logic without extensive knowledge of VR technology or computer modeling. The latter feature is especially useful in conveying information to students and nontechnical decision makers, demonstrating the impact of each of a complicated set of variables with reproducible results

  4. 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

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

    International Nuclear Information System (INIS)

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

    1995-01-01

    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

  6. 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.

  7. Effect of spray volume on the deposition, viability and infectivity of entomopathogenic nematodes in a foliar spray on vegetables.

    Science.gov (United States)

    Brusselman, Eva; Beck, Bert; Pollet, Sabien; Temmerman, Femke; Spanoghe, Pieter; Moens, Maurice; Nuyttens, David

    2012-10-01

    Spray volume can influence the amount of free water on the leaf surface and subsequently the ability of entomopathogenic nematodes (EPNs) to move. In this study, an investigation was made of the effect of spray volume (548, 730 and 1095 L ha(-1) ) on the deposition, viability and infectivity of EPNs against Galleria mellonella on savoy cabbage, cauliflower and leek. Increasing spray volume decreased nematode deposition on 7.1 cm2 leek leaf discs at a 15° angle with the spray nozzle. Although the number of living nematodes observed on leek after 240 min of exposure was not significantly different between the low-volume application (548 L ha(-1) ) and the high-volume application (1095 L ha(-1) ), a greater infectivity was obtained in the latter application. The higher number of droplets deposited on the leek discs in the high-volume application may have stimulated nematode movement. No significant effect of spray volume was observed on the relative deposition of Steinernema carpocapsae on the bottom side of cauliflower and savoy cabbage leaf discs. In spite of the low S. carpocapsae deposition on the bottom side of the savoy cabbage discs, high infectivity was obtained against G. mellonella. Using the lowest spray volume on savoy cabbage, infectivity decreased with increasing exposure time, while infectivity was not affected by exposure time when a spray volume of 730 L ha(-1) or more was used. Spray volume is an important application parameter, as it affects nematode infectivity. Future research should investigate the effect of spray volume in the field and its influence on the effect of adjuvants. Copyright © 2012 Society of Chemical Industry.

  8. Deposition to forests in Europe: most important factors influencing dry deposition and models used for generalisation

    International Nuclear Information System (INIS)

    Erisman, Jan Willem; Draaijers, Geert

    2003-01-01

    The influence of forest characteristics on deposition can be modelled reasonably well; forest edge effects and dynamical processes are still uncertain. - Dry deposition of gases and particles to forests is influenced by factors influencing the turbulent transport, such as wind speed, tree height, canopy closure, LAI, etc. as well as by factors influencing surface condition, such as precipitation, relative humidity, global radiation, etc. In this paper, an overview of these factors is given and it is shown which are the most important determining temporal and spatial variation of dry deposition of sodium and sulphur. Furthermore, it is evaluated how well current deposition models are able to describe the temporal and spatial variation in dry deposition. It is concluded that the temporal variation is not modelled well enough, because of limited surface-wetness exchange parameterisations. The influence of forest characteristics are modelled reasonably well, provided enough data describing the forests and the spatial variation in concentration is available. For Europe these data are not available. The means to decrease the atmospheric deposition through forest management is discussed

  9. 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

  10. EARTHWORK VOLUME CALCULATION FROM DIGITAL TERRAIN MODELS

    Directory of Open Access Journals (Sweden)

    JANIĆ Milorad

    2015-06-01

    Full Text Available Accurate calculation of cut and fill volume has an essential importance in many fields. This article shows a new method, which has no approximation, based on Digital Terrain Models. A relatively new mathematical model is developed for that purpose, which is implemented in the software solution. Both of them has been tested and verified in the praxis on several large opencast mines. This application is developed in AutoLISP programming language and works in AutoCAD environment.

  11. Quartz-pebble-conglomerate gold deposits: Chapter P in Mineral deposit models for resource assessment

    Science.gov (United States)

    Taylor, Ryan D.; Anderson, Eric D.

    2018-05-17

    Quartz-pebble-conglomerate gold deposits represent the largest repository of gold on Earth, largely due to the deposits of the Witwatersrand Basin, which account for nearly 40 percent of the total gold produced throughout Earth’s history. This deposit type has had a controversial history in regards to genetic models. However, most researchers conclude that they are paleoplacer deposits that have been modified by metamorphism and hydrothermal fluid flow subsequent to initial sedimentation.The deposits are found exclusively within fault-bounded depositional basins. The periphery of these basins commonly consists of granite-greenstone terranes, classic hosts for lode gold that source the detrital material infilling the basin. The gold reefs are typically located along unconformities or, less commonly, at the top of sedimentary beds. Large quartz pebbles and heavy-mineral concentrates are found associated with the gold. Deposits that formed prior to the Great Oxidation Event (circa 2.4 giga-annum [Ga]) contain pyrite, whereas younger deposits contain iron oxides. Uranium minerals and hydrocarbons are also notable features of some deposits.Much of the gold in these types of deposits forms crystalline features that are the product of local remobilization. However, some gold grains preserve textures that are undoubtedly of detrital origin. Other heavy minerals, such as pyrite, contain growth banding that is truncated along broken margins, which indicates that they were transported into place as opposed to forming by in situ growth in a hydrothermal setting.The ore tailings associated with these deposits commonly contain uranium-rich minerals and sulfides. Oxidation of the sulfides releases sulfuric acid and mobilizes various metals into the environment. The neutralizing potential of the tailings is minimal, since carbonate minerals are rare. The continuity of the tabular ore bodies, such as those of the Witwatersrand Basin, has allowed these mines to be the deepest in

  12. Modelled transport and deposition of sulphur over Southern Africa

    CSIR Research Space (South Africa)

    Zunckel, M

    2000-01-01

    Full Text Available Ambient SO2 concentrations and atmospheric deposition of sulphur resulting from emissions on the industrialised highveld region of South Africa are estimated using the multi-scale atmospheric transport and chemistry (MATCH) modelling system...

  13. 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.

  14. 1988 DOE model conference proceedings: Volume 4

    International Nuclear Information System (INIS)

    1988-01-01

    These Proceedings of the October 3-7, 1988, DOE Model Conference are a compilation of the papers that were presented in the technical or poster sessions at the conference. Papers and posters not submitted for publication are not included in the Proceedings. The Table of Contents lists the titles of papers as well as the names of the presenters. These individuals are not, in all cases, the primary authors of the papers published. The actual title pages, appearing later with the papers, show the primary author(s) and all co-authors. The papers in all three volumes of the Proceedings appear as they were originally submitted for publication and have not been edited or changed in any way. Topics discussed in Volume 4 include site characterization and remediation projects, environmental monitoring and modeling; disposal site selection and facility design, risk assessment, safety and health issues, and site remediation technology

  15. 1988 DOE model conference proceedings: Volume 4

    Energy Technology Data Exchange (ETDEWEB)

    1988-01-01

    These Proceedings of the October 3-7, 1988, DOE Model Conference are a compilation of the papers that were presented in the technical or poster sessions at the conference. Papers and posters not submitted for publication are not included in the Proceedings. The Table of Contents lists the titles of papers as well as the names of the presenters. These individuals are not, in all cases, the primary authors of the papers published. The actual title pages, appearing later with the papers, show the primary author(s) and all co-authors. The papers in all three volumes of the Proceedings appear as they were originally submitted for publication and have not been edited or changed in any way. Topics discussed in Volume 4 include site characterization and remediation projects, environmental monitoring and modeling; disposal site selection and facility design, risk assessment, safety and health issues, and site remediation technology.

  16. A nonhuman primate aerosol deposition model for toxicological and pharmaceutical studies

    Energy Technology Data Exchange (ETDEWEB)

    Martonen, T.B.; Katz, I.M.; Musante, C.J. [US EPA, Research Triangle Park, NC (USA)

    2001-07-01

    Nonhuman primates may be used as human surrogates in inhalation exposure studies to assess either the (1) adverse health effects of airborne particulate matter or (2) therapeutic effects of aerosolized drugs and proteins. Mathematical models describing the behavior and fate of inhaled aerosols may be used to complement such laboratory investigations. In this work a mathematical description of the rhesus monkey (Macaca mulatta) lung is presented for use with an aerosol deposition model. Deposition patterns of 0.01- to 5-{mu}m-diameter monodisperse aerosols within lungs were calculated for 3 monkey lung models (using different descriptions of alveolated regions) and compared to human lung results obtained using a previously validated mathematical model of deposition physics. The findings suggest that there are significant differences between deposition patterns in monkeys and humans. The nonhuman primates had greater exposures to inhaled substances, particularly on the basis of deposition per unit airway surface area. However, the different alveolar volumes in the rhesus monkey models had only minor effects on aerosol dosimetry within those lungs. By being aware of such quantitative differences, investigators can employ the respective primate models (human and nonhuman) to more effectively design and interpret the results of future inhalation exposure experiments.

  17. Effects of uncertainty in model predictions of individual tree volume on large area volume estimates

    Science.gov (United States)

    Ronald E. McRoberts; James A. Westfall

    2014-01-01

    Forest inventory estimates of tree volume for large areas are typically calculated by adding model predictions of volumes for individual trees. However, the uncertainty in the model predictions is generally ignored with the result that the precision of the large area volume estimates is overestimated. The primary study objective was to estimate the effects of model...

  18. Droplet model of pyrocarbon deposition from the gas phase. [HTGR

    Energy Technology Data Exchange (ETDEWEB)

    Linke, J; Koizlik, K; Luhleich, H; Nickel, H

    1975-01-15

    Based on extensive earlier work a model has been developed to describe the formation of carbon by pyrolysis of gaseous hydrocarbons. One of the central statements of this model is the assumption of the existence of a quasi liquid carbon phase during deposition process.This model is described and is discussed as are the consequences for the material properties and structural parameters which arise from it. To review the droplet model, statically deposited pyrocarbon is examined by characterization methods suitable to analyze just these structural parameters.The results prove the model conceptions to be realistic.

  19. Deposition of inhaled radionuclides in bronchial airways: Implications for extrapolation modeling

    International Nuclear Information System (INIS)

    Balashazy, I.; Hofmann, W.; Heistracher, T.

    1996-01-01

    The laboratory rat has frequently been used as a human surrogate to estimate potential health effects following the inhalation of radioactive aerosol particles. Interspecies differences in biological response are commonly related to interspecies differences in particle deposition efficiencies. In addition, the documented site selectivity of bronchial carcinomas suggests that localized particle deposition patterns within bronchial airway bifurcations may have important implications for inhalation risk assessments. Interspecies differences in particle deposition patterns may be related primarily to differences in airway morphometries. Thus the validity of extrapolating rat deposition data to human inhalation conditions depends on their morphometric similarities and differences. It is well known that there are significant structural differences between the human - rather symmetric - and the rat - monopodial - airway systems. In the present approach, we focus on localized deposition patterns and deposition efficiencies in selected asymmetric bronchial airway bifurcations, whose diameters, lengths and branching angles were derived from the stochastic airway models of human and rat lungs (Koblinger and Hofmann, 1985;1988), which are based on the morphometric data of Raabe et al. (1976). The effects of interspecies differences in particle deposition patterns are explored in this study for two asymmetric bifurcation geometries in segmental bronchi and terminal bronchioles of both the human and rat lungs at different particle sizes. In order to examine the effect of flow rate on particle deposition in the human lung, we selected two different minute volumes, i.e., 10 and 60 1 min -1 , which are representative of low and heavy physical activity breathing conditions. In the case of the rat we used a minute volume of 0.234 1 min -1 (Hofmann et al., 1993)

  20. Analytic model of heat deposition in spallation neutron target

    International Nuclear Information System (INIS)

    Findlay, D.J.S.

    2015-01-01

    A simple analytic model for estimating deposition of heat in a spallation neutron target is presented—a model that can readily be realised in an unambitious spreadsheet. The model is based on simple representations of the principal underlying physical processes, and is intended largely as a ‘sanity check’ on results from Monte Carlo codes such as FLUKA or MCNPX.

  1. Analytic model of heat deposition in spallation neutron target

    Energy Technology Data Exchange (ETDEWEB)

    Findlay, D.J.S.

    2015-12-11

    A simple analytic model for estimating deposition of heat in a spallation neutron target is presented—a model that can readily be realised in an unambitious spreadsheet. The model is based on simple representations of the principal underlying physical processes, and is intended largely as a ‘sanity check’ on results from Monte Carlo codes such as FLUKA or MCNPX.

  2. 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...

  3. 1988 DOE model conference proceedings: Volume 2

    International Nuclear Information System (INIS)

    1988-01-01

    These Proceedings of the October 3 - 7, 1988, DOE Model Conference are a compilation of the papers that were presented in the technical or poster sessions at the conference. Papers and posters not submitted for publication are not included in the proceedings. The Table of Contents lists the titles of papers as well as the names of the presenters. These individuals are not, in all cases, the primary authors of the papers published. The actual title pages, appearing later with the papers, show the primary author(s) and all co-authors. The papers in all three volumes of the Proceedings appear as they were originally submitted for publication and have not been edited or changed in any way. Volume 2 contains information on environmental restoration at federal facilities, waste disposal technology, quality assurance, contingency planning and emergency response, decontamination and decommissioning, environmental restoration, and public involvement in waste management

  4. 1988 DOE model conference proceedings: Volume 5

    Energy Technology Data Exchange (ETDEWEB)

    1988-01-01

    These Proceedings of the October 3--7, 1988 DOE Model Conference are a compilation of the papers that were presented in the technical or poster sessions at the conference papers and posters not submitted for publication are not included in the Proceedings. The Table of Contents lists the titles of papers as well as the names of the presenters. These individuals are not, in all cases, the primary authors of the papers published. The actual title pages, appearing later with the papers, show the primary author(s) and all co-authors. The papers in all three volumes of the Proceedings appear as they were originally submitted for publication and have not been edited or changed in any way. Topics discussed in Volume 5 include environmental assessments and program strategies, waste treatment technologies, and regulations and compliance studies.

  5. 1988 DOE model conference proceedings: Volume 1

    International Nuclear Information System (INIS)

    1988-01-01

    These Proceedings of the October 3-7, 1988, DOE Model Conference are a compilation of the papers that were presented in the technical or poster sessions at the conference. Papers and posters not submitted for publication are not included in the Proceedings. The Table of Contents lists the titles of papers as well as the names of the presenters. These individuals are not, in all cases, the primary authors of the papers published. The actual title pages, appearing later with the papers, show the primary author(s) and all co-authors. The papers in all three volumes of the Proceedings appear as they were originally submitted for publication and have not been edited or changed in any way. Topics included in Volume 1 are Environmental Data Management, Site characterization technology, Wastewater treatment, Waste management in foreign countries, Transuranic waste management, and Groundwater characterization and treatment

  6. 1988 DOE model conference proceedings: Volume 3

    International Nuclear Information System (INIS)

    1988-01-01

    These Proceedings of the October 3 - 7, 1988, DOE Model Conference are a compilation of the papers that were presented in the technical or poster sessions at the conference. Papers and posters not submitted for publication are not included in the Proceedings. The Table of Contents lists the titles of papers as well as the names of the presenters. These individuals are not, in all cases, the primary authors of the papers published. The actual title pages, appearing later with the papers, show the primary author(s) and all co-authors. The papers in all three volumes of the proceedings appear as they were originally submitted for publication and have not been edited or changed in any way. Topics included in Volume 3 include treatment of soils, waste characterization and certification, waste minimization site remediation management plans and programs, and training programs

  7. 1988 DOE model conference proceedings: Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    1988-01-01

    These Proceedings of the October 3-7, 1988, DOE Model Conference are a compilation of the papers that were presented in the technical or poster sessions at the conference. Papers and posters not submitted for publication are not included in the Proceedings. The Table of Contents lists the titles of papers as well as the names of the presenters. These individuals are not, in all cases, the primary authors of the papers published. The actual title pages, appearing later with the papers, show the primary author(s) and all co-authors. The papers in all three volumes of the Proceedings appear as they were originally submitted for publication and have not been edited or changed in any way. Topics included in Volume 1 are Environmental Data Management, Site characterization technology, Wastewater treatment, Waste management in foreign countries, Transuranic waste management, and Groundwater characterization and treatment.

  8. 1988 DOE model conference proceedings: Volume 5

    International Nuclear Information System (INIS)

    1988-01-01

    These Proceedings of the October 3--7, 1988 DOE Model Conference are a compilation of the papers that were presented in the technical or poster sessions at the conference papers and posters not submitted for publication are not included in the Proceedings. The Table of Contents lists the titles of papers as well as the names of the presenters. These individuals are not, in all cases, the primary authors of the papers published. The actual title pages, appearing later with the papers, show the primary author(s) and all co-authors. The papers in all three volumes of the Proceedings appear as they were originally submitted for publication and have not been edited or changed in any way. Topics discussed in Volume 5 include environmental assessments and program strategies, waste treatment technologies, and regulations and compliance studies

  9. A dynamical model on deposit and loan of banking: A bifurcation analysis

    Science.gov (United States)

    Sumarti, Novriana; Hasmi, Abrari Noor

    2015-09-01

    A dynamical model, which is one of sophisticated techniques using mathematical equations, can determine the observed state, for example bank profits, for all future times based on the current state. It will also show small changes in the state of the system create either small or big changes in the future depending on the model. In this research we develop a dynamical system of the form: d/D d t =f (D ,L ,rD,rL,r ), d/L d t =g (D ,L ,rD,rL,r ), Here D and rD are the volume of deposit and its rate, L and rL are the volume of loan and its rate, and r is the interbank market rate. There are parameters required in this model which give connections between two variables or between two derivative functions. In this paper we simulate the model for several parameters values. We do bifurcation analysis on the dynamics of the system in order to identify the appropriate parameters that control the stability behaviour of the system. The result shows that the system will have a limit cycle for small value of interest rate of loan, so the deposit and loan volumes are fluctuating and oscillating extremely. If the interest rate of loan is too high, the loan volume will be decreasing and vanish and the system will converge to its carrying capacity.

  10. 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.

  11. Application of concentration-volume fractal method in induced polarization and resistivity data interpretation for Cu-Mo porphyry deposits exploration, case study: Nowchun Cu-Mo deposit, SE Iran

    Directory of Open Access Journals (Sweden)

    L. Daneshvar Saein

    2012-08-01

    Full Text Available The aim of this study is the utilization of the concentration-volume (C-V fractal method based on geoelectrical data including induced polarization (IP and resistivity (RS in targeting areas hosting different sulfidic mineralization zones in Nowchun Cu-Mo porphyry deposit, SE Iran. The C-V fractal model employed in this research in order to separate high and moderate sulfidic zones from low sulfidic zone and barren wall rocks in the deposit is corresponding to chargeability and resistivity. Results obtained from the C-V method indicate that there is a positive correlation between subsurface mineralization and sulfide mineralized zones; additionally, use of the C-V method based on geophysical data is recognized as an accurate approach for delineation of various mineralization zones in the depth for optimization of mineral exploration operation, particularly in porphyry deposits.

  12. 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...... parts to subsequently use in a Lost Wax Casting process, multi-material Additive Manufacturing and the use of wax as support material during the production of complicated parts. Moreover it is believed that including waxes among the materials usable in FDM would promote new ways of using and exploring...

  13. 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....

  14. Application of Rqd-Number and Rqd-Volume Multifractal Modelling to Delineate Rock Mass Characterisation in Kahang Cu-Mo Porphyry Deposit, Central Iran / Zastosowanie Metod Modelowania Numerycznego Oraz Modelowania Fraktalnego do Analizy JAKOŚCI SKAŁ W Celu OKREŚLENIA Charakterystyki GÓROTWORU W Obszarze ZŁOŻA Cu-Mo W Kahang, ŚRODKOWY Iran

    Science.gov (United States)

    Yasrebi, Amir Bijan; Wetherelt, Andrew; Foster, Patrick J.; Afzal, Peyman; Coggan, John; Ahangaran, Dariush Kaveh

    2013-12-01

    Identification of rock mass properties in terms of Rock Quality Designation (RQD) plays a significant role in mine planning and design. This study aims to separate the rock mass characterisation based on RQD data analysed from 48 boreholes in Kahang Cu-Mo porphyry deposit situated in the central Iran utilising RQD-Volume (RQD-V) and RQD-Number (RQD-N) fractal models. The log-log plots for RQD-V and RQD-N models show four rock mass populations defined by RQD thresholds of 3.55, 25.12 and 89.12% and 10.47, 41.68 and 83.17% respectively which represent very poor, poor, good and excellent rocks based on Deere and Miller rock classification. The RQD-V and RQD-N models indicate that the excellent rocks are situated in the NW and central parts of this deposit however, the good rocks are located in the most parts of the deposit. The results of validation of the fractal models with the RQD block model show that the RQD-N fractal model of excellent rock quality is better than the RQD-V fractal model of the same rock quality. Correlation between results of the fractal and the geological models illustrates that the excellent rocks are associated with porphyric quartz diorite (PQD) units. The results reveal that there is a multifractal nature in rock characterisation with respect to RQD for the Kahang deposit. The proposed fractal model can be intended for the better understanding of the rock quality for purpose of determination of the final pit slope. Identyfikacja właściwości górotworu odgrywa zasadniczą rolę w planowaniu wydobycia i projektowaniu kopalni. Praca niniejsza ma na celu określenie charakterystyki górotworu w oparciu o dane o jakości skał zebrane na podstawie próbek uzyskanych z 48 odwiertów wykonanych w złożu porfiru Cu-Mo w Kahang, zalegającym w środkowym Iranie przy użyciu modeli fraktalnych RQD-V - Rock Quality Determination-Volume [Określenie jakości skał-objętość]) i RQD-N (Rock Quality Determination-Number [Określenie jakości ska

  15. Molecular Models for DSMC Simulations of Metal Vapor Deposition

    OpenAIRE

    Venkattraman, A; Alexeenko, Alina A

    2010-01-01

    The direct simulation Monte Carlo (DSMC) method is applied here to model the electron‐beam (e‐beam) physical vapor deposition of copper thin films. A suitable molecular model for copper‐copper interactions have been determined based on comparisons with experiments for a 2D slit source. The model for atomic copper vapor is then used in axi‐symmetric DSMC simulations for analysis of a typical e‐beam metal deposition system with a cup crucible. The dimensional and non‐dimensional mass fluxes obt...

  16. Advances in the exploration model for Athabasca unconformity uranium deposits

    International Nuclear Information System (INIS)

    Wheatley, K.; Murphy, J.; Leppin, M.; Cutts, C.; Climie, J.A.

    1997-01-01

    This paper covers the genetic model of ore formation and exploration techniques Uranerz Exploration and Mining is presently using to explore for unconformity uranium deposits in the deeper parts of the Athabasca Basin. The main objectives of this paper are: 1) to present a genetic model for unconformity uranium deposits which is being used in our current exploration strategy, and 2) to present the sequence of exploration techniques used by Uranerz to explore for uranium in areas of the Athabasca Basin with up to 1000 m of sandstone cover. The Athabasca unconformity deposits are located in northern Saskatchewan, Canada. Within the Precambrian Athabasca Basin, exploration companies have discovered 18 uranium deposits. These contain more than 500 million kilograms of uranium, with average grades ranging from 0.3 to 12%. Uranerz discovered the Key Lake deposits in 1975, currently the largest and richest open pit uranium mine in the world. Uranerz also holds interests in the Rabbit Lake, Midwest Lake and McArthur River deposits, all in Saskatchewan, and is also actively exploring for uranium worldwide. The first discovery in the eastern Athabasca Basin was in 1968 at Rabbit Lake, followed by Key Lake in 1975. Both deposits had surficial indicators, such as radioactive boulders, strong geochemical anomalies in the surrounding lakes and swamps, and well-defined geophysical signatures. After the Key Lake discovery, an exploration model was devised which incorporated the underlying graphitic horizon and its strong electro-magnetic signature. Since then, there have been numerous new discoveries made by systematically drilling along these electro-magnetic conductors. The advancements in geophysical and geochemical techniques have led to discoveries at increasing depths. In 1988, the McArthur River deposit was discovered at a depth of 500 m. (author). 6 refs

  17. Modelling of diamond deposition microwave cavity generated plasmas

    International Nuclear Information System (INIS)

    Hassouni, K; Silva, F; Gicquel, A

    2010-01-01

    Some aspects of the numerical modelling of diamond deposition plasmas generated using microwave cavity systems are discussed. The paper mainly focuses on those models that allow (i) designing microwave cavities in order to optimize the power deposition in the discharge and (ii) estimating the detailed plasma composition in the vicinity of the substrate surface. The development of hydrogen plasma models that may be used for the self-consistent simulation of microwave cavity discharge is first discussed. The use of these models for determining the plasma configuration, composition and temperature is illustrated. Examples showing how to use these models in order to optimize the cavity structure and to obtain stable process operations are also given. A transport model for the highly reactive H 2 /CH 4 moderate pressure discharges is then presented. This model makes possible the determination of the time variation of plasma composition and temperature on a one-dimensional domain located on the plasma axis. The use of this model to analyse the transport phenomena and the chemical process in diamond deposition plasmas is illustrated. The model is also utilized to analyse pulsed mode discharges and the benefit they can bring as far as diamond growth rate and quality enhancement are concerned. We, in particular, show how the model can be employed to optimize the pulse waveform in order to improve the deposition process. Illustrations on how the model can give estimates of the species density at the growing substrate surface over a wide domain of deposition conditions are also given. This brings us to discuss the implication of the model prediction in terms of diamond growth rate and quality. (topical review)

  18. A Lagrangian Approach for Calculating Microsphere Deposition in a One-Dimensional Lung-Airway Model.

    Science.gov (United States)

    Vaish, Mayank; Kleinstreuer, Clement

    2015-09-01

    Using the open-source software openfoam as the solver, a novel approach to calculate microsphere transport and deposition in a 1D human lung-equivalent trumpet model (TM) is presented. Specifically, for particle deposition in a nonlinear trumpetlike configuration a new radial force has been developed which, along with the regular drag force, generates particle trajectories toward the wall. The new semi-empirical force is a function of any given inlet volumetric flow rate, micron-particle diameter, and lung volume. Particle-deposition fractions (DFs) in the size range from 2 μm to 10 μm are in agreement with experimental datasets for different laminar and turbulent inhalation flow rates as well as total volumes. Typical run times on a single processor workstation to obtain actual total deposition results at comparable accuracy are 200 times less than that for an idealized whole-lung geometry (i.e., a 3D-1D model with airways up to 23rd generation in single-path only).

  19. Modeling of gas flow and deposition profile in HWCVD processes

    Energy Technology Data Exchange (ETDEWEB)

    Pflug, Andreas; Höfer, Markus; Harig, Tino; Armgardt, Markus; Britze, Chris; Siemers, Michael; Melzig, Thomas; Schäfer, Lothar

    2015-11-30

    Hot wire chemical vapor deposition (HWCVD) is a powerful technology for deposition of high quality films on large area, where drawbacks of plasma based technology such as defect generation by ion bombardment and high equipment costs are omitted. While processes for diamond coatings using H{sub 2} and CH{sub 4} as precursor have been investigated in detail since 1990 and have been transferred to industry, research also focuses on silicon based coatings with H{sub 2}, SiH{sub 4} and NH{sub 3} as process gases. HWCVD of silicon based coatings is a promising alternative for state-of-the-art radiofrequency-plasma enhanced chemical vapor deposition reactors. The film formation in HWCVD results from an interaction of several concurrent chemical reactions such as gas phase chemistry, film deposition, abstraction of surplus hydrogen bonds and etching by atomic hydrogen. Since there is no easy relation between process parameters and resulting deposition profiles, substantial experimental effort is required to optimize the process for a given film specification and the desired film uniformity. In order to obtain a deeper understanding of the underlying mechanisms and to enable an efficient way of process optimization, simulation methods come into play. While diamond deposition occurs at pressures in the range of several kPa HWCVD deposition of Si based coatings operates at pressures in the 0.1–30 Pa range. In this pressure regime, particle based simulation methods focused on solving the Boltzmann equation are computationally feasible. In comparison to computational fluid dynamics this yields improved accuracy even near small gaps or orifices, where characteristic geometric dimensions approach the order of the mean free path of gas molecules. At Fraunhofer IST, a parallel implementation of the Direct Simulation Monte Carlo (DSMC) method extended by a reactive wall chemistry model is developed. To demonstrate the feasibility of three-dimensional simulation of HWCVD processes

  20. Compilation of information on uncertainties involved in deposition modeling

    International Nuclear Information System (INIS)

    Lewellen, W.S.; Varma, A.K.; Sheng, Y.P.

    1985-04-01

    The current generation of dispersion models contains very simple parameterizations of deposition processes. The analysis here looks at the physical mechanisms governing these processes in an attempt to see if more valid parameterizations are available and what level of uncertainty is involved in either these simple parameterizations or any more advanced parameterization. The report is composed of three parts. The first, on dry deposition model sensitivity, provides an estimate of the uncertainty existing in current estimates of the deposition velocity due to uncertainties in independent variables such as meteorological stability, particle size, surface chemical reactivity and canopy structure. The range of uncertainty estimated for an appropriate dry deposition velocity for a plume generated by a nuclear power plant accident is three orders of magnitude. The second part discusses the uncertainties involved in precipitation scavenging rates for effluents resulting from a nuclear reactor accident. The conclusion is that major uncertainties are involved both as a result of the natural variability of the atmospheric precipitation process and due to our incomplete understanding of the underlying process. The third part involves a review of the important problems associated with modeling the interaction between the atmosphere and a forest. It gives an indication of the magnitude of the problem involved in modeling dry deposition in such environments. Separate analytics have been done for each section and are contained in the EDB

  1. 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.

  2. 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)

  3. 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)

  4. 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.

  5. Numerical modelling of laser rapid prototyping by fusion wire deposit

    OpenAIRE

    Arbaoui , Larbi; Masse , J.E.; Barrallier , Laurent; Mocellin , Katia

    2010-01-01

    International audience; A finite element model has been developed to simulate an innovative laser rapid prototyping process. Several numerical developments have been implemented in order to simulate the main steps of the rapid prototyping process: injection, heating, phase change and deposit. The numerical model also takes into account different phenomena: surface tension in the liquid state, asborptivity and plasma effects during materiallaser interaction. The threedimensional model is based...

  6. Modeling Subgrid Scale Droplet Deposition in Multiphase-CFD

    Science.gov (United States)

    Agostinelli, Giulia; Baglietto, Emilio

    2017-11-01

    The development of first-principle-based constitutive equations for the Eulerian-Eulerian CFD modeling of annular flow is a major priority to extend the applicability of multiphase CFD (M-CFD) across all two-phase flow regimes. Two key mechanisms need to be incorporated in the M-CFD framework, the entrainment of droplets from the liquid film, and their deposition. Here we focus first on the aspect of deposition leveraging a separate effects approach. Current two-field methods in M-CFD do not include appropriate local closures to describe the deposition of droplets in annular flow conditions. As many integral correlations for deposition have been proposed for lumped parameters methods applications, few attempts exist in literature to extend their applicability to CFD simulations. The integral nature of the approach limits its applicability to fully developed flow conditions, without geometrical or flow variations, therefore negating the scope of CFD application. A new approach is proposed here that leverages local quantities to predict the subgrid-scale deposition rate. The methodology is first tested into a three-field approach CFD model.

  7. 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.

  8. 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

  9. 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...

  10. 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....

  11. 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

  12. 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

  13. True Volumes of Slope Failure Estimated From a Quaternary Mass-Transport Deposit in the Northern South China Sea

    Science.gov (United States)

    Sun, Qiliang; Alves, Tiago M.; Lu, Xiangyang; Chen, Chuanxu; Xie, Xinong

    2018-03-01

    Submarine slope failure can mobilize large amounts of seafloor sediment, as shown in varied offshore locations around the world. Submarine landslide volumes are usually estimated by mapping their tops and bases on seismic data. However, two essential components of the total volume of failed sediments are overlooked in most estimates: (a) the volume of subseismic turbidites generated during slope failure and (b) the volume of shear compaction occurring during the emplacement of failed sediment. In this study, the true volume of a large submarine landslide in the northern South China Sea is estimated using seismic, multibeam bathymetry and Ocean Drilling Program/Integrated Ocean Drilling Program well data. The submarine landslide was evacuated on the continental slope and deposited in an ocean basin connected to the slope through a narrow moat. This particular character of the sea floor provides an opportunity to estimate the amount of strata remobilized by slope instability. The imaged volume of the studied landslide is 1035 ± 64 km3, 406 ± 28 km3 on the slope and 629 ± 36 km3 in the ocean basin. The volume of subseismic turbidites is 86 km3 (median value), and the volume of shear compaction is 100 km3, which are 8.6% and 9.7% of the landslide volume imaged on seismic data, respectively. This study highlights that the original volume of the failed sediments is significantly larger than that estimated using seismic and bathymetric data. Volume loss related to the generation of landslide-related turbidites and shear compaction must be considered when estimating the total volume of failed strata in the submarine realm.

  14. 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

  15. 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

  16. 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.

  17. Characteristics of debris avalanche deposits inferred from source volume estimate and hummock morphology around Mt. Erciyes, central Turkey

    Science.gov (United States)

    Hayakawa, Yuichi S.; Yoshida, Hidetsugu; Obanawa, Hiroyuki; Naruhashi, Ryutaro; Okumura, Koji; Zaiki, Masumi; Kontani, Ryoichi

    2018-02-01

    Debris avalanches caused by volcano sector collapse often form characteristic depositional landforms such as hummocks. Sedimentological and geomorphological analyses of debris avalanche deposits (DADs) are crucial to clarify the size, mechanisms, and emplacement of debris avalanches. We describe the morphology of hummocks on the northeastern flank of Mt. Erciyes in Kayseri, central Turkey, likely formed in the late Pleistocene. Using a remotely piloted aircraft system (RPAS) and the structure-from-motion and multi-view stereo (SfM-MVS) photogrammetry, we obtained high-definition digital elevation model (DEM) and orthorectified images of the hummocks to investigate their geometric features. We estimated the source volume of the DAD by reconstructing the topography of the volcano edifice using a satellite-based DEM. We examined the topographic cross sections based on the slopes around the scar regarded as remnant topography. Spatial distribution of hummocks is anomalously concentrated at a certain distance from the source, unlike those that follow the distance-size relationship. The high-definition land surface data by RPAS and SfM revealed that many of the hummocks are aligned toward the flow direction of the debris avalanche, suggesting that the extensional regime of the debris avalanche was dominant. However, some displaced hummocks were also found, indicating that the compressional regime of the flow contributed to the formation of hummocks. These indicate that the flow and emplacement of the avalanche were constrained by the topography. The existing caldera wall forced the initial eastward flow to move northward, and the north-side caldera wall forced the flow into the narrow and steepened outlet valley where the sliding debris underwent a compressional regime, and out into the unconfined terrain where the debris was most likely emplaced on an extensional regime. Also, the estimated volume of 12-15 × 108 m3 gives a mean thickness of 60-75 m, which is much

  18. Characteristics of debris avalanche deposits inferred from source volume estimate and hummock morphology around Mt. Erciyes, central Turkey

    Directory of Open Access Journals (Sweden)

    Y. S. Hayakawa

    2018-02-01

    Full Text Available Debris avalanches caused by volcano sector collapse often form characteristic depositional landforms such as hummocks. Sedimentological and geomorphological analyses of debris avalanche deposits (DADs are crucial to clarify the size, mechanisms, and emplacement of debris avalanches. We describe the morphology of hummocks on the northeastern flank of Mt. Erciyes in Kayseri, central Turkey, likely formed in the late Pleistocene. Using a remotely piloted aircraft system (RPAS and the structure-from-motion and multi-view stereo (SfM–MVS photogrammetry, we obtained high-definition digital elevation model (DEM and orthorectified images of the hummocks to investigate their geometric features. We estimated the source volume of the DAD by reconstructing the topography of the volcano edifice using a satellite-based DEM. We examined the topographic cross sections based on the slopes around the scar regarded as remnant topography. Spatial distribution of hummocks is anomalously concentrated at a certain distance from the source, unlike those that follow the distance–size relationship. The high-definition land surface data by RPAS and SfM revealed that many of the hummocks are aligned toward the flow direction of the debris avalanche, suggesting that the extensional regime of the debris avalanche was dominant. However, some displaced hummocks were also found, indicating that the compressional regime of the flow contributed to the formation of hummocks. These indicate that the flow and emplacement of the avalanche were constrained by the topography. The existing caldera wall forced the initial eastward flow to move northward, and the north-side caldera wall forced the flow into the narrow and steepened outlet valley where the sliding debris underwent a compressional regime, and out into the unconfined terrain where the debris was most likely emplaced on an extensional regime. Also, the estimated volume of 12–15 × 108 m3 gives a mean thickness of

  19. 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.

  20. Stem biomass and volume models of selected tropical tree species ...

    African Journals Online (AJOL)

    Stem biomass and stem volume were modelled as a function of diameter (at breast height; Dbh) and stem height (height to the crown base). Logarithmic models are presented that utilise Dbh and height data to predict tree component biomass and stem volumes. Alternative models are given that afford prediction based on ...

  1. Relationships between sleep quality and brain volume, metabolism, and amyloid deposition in late adulthood.

    Science.gov (United States)

    Branger, Pierre; Arenaza-Urquijo, Eider M; Tomadesso, Clémence; Mézenge, Florence; André, Claire; de Flores, Robin; Mutlu, Justine; de La Sayette, Vincent; Eustache, Francis; Chételat, Gaël; Rauchs, Géraldine

    2016-05-01

    Recent studies in mouse models of Alzheimer's disease (AD) and in humans suggest that sleep disruption and amyloid-beta (Aβ) accumulation are interrelated, and may, thus, exacerbate each other. We investigated the association between self-reported sleep variables and neuroimaging data in 51 healthy older adults. Participants completed a questionnaire assessing sleep quality and quantity and underwent positron emission tomography scans using [18F]florbetapir and [18F]fluorodeoxyglucose and an magnetic resonance imaging scan to measure Aβ burden, hypometabolism, and atrophy, respectively. Longer sleep latency was associated with greater Aβ burden in prefrontal areas. Moreover, the number of nocturnal awakenings was negatively correlated with gray matter volume in the insular region. In asymptomatic middle-aged and older adults, lower self-reported sleep quality was associated with greater Aβ burden and lower volume in brain areas relevant in aging and AD, but not with glucose metabolism. These results highlight the potential relevance of preserving sleep quality in older adults and suggest that sleep may be a factor to screen for in individuals at risk for AD. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. 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).

  3. Mesorad dose assessment model. Volume 1. Technical basis

    International Nuclear Information System (INIS)

    Scherpelz, R.I.; Bander, T.J.; Athey, G.F.; Ramsdell, J.V.

    1986-03-01

    MESORAD is a dose assessment model for emergency response applications. Using release data for as many as 50 radionuclides, the model calculates: (1) external doses resulting from exposure to radiation emitted by radionuclides contained in elevated or deposited material; (2) internal dose commitment resulting from inhalation; and (3) total whole-body doses. External doses from airborne material are calculated using semi-infinite and finite cloud approximations. At each stage in model execution, the appropriate approximation is selected after considering the cloud dimensions. Atmospheric processes are represented in MESORAD by a combination of Lagrangian puff and Gaussian plume dispersion models, a source depletion (deposition velocity) dry deposition model, and a wet deposition model using washout coefficients based on precipitation rates

  4. Environmental fate model for ultra-low-volume insecticide applications used for adult mosquito management

    Science.gov (United States)

    Schleier, Jerome J.; Peterson, Robert K.D.; Irvine, Kathryn M.; Marshall, Lucy M.; Weaver, David K.; Preftakes, Collin J.

    2012-01-01

    One of the more effective ways of managing high densities of adult mosquitoes that vector human and animal pathogens is ultra-low-volume (ULV) aerosol applications of insecticides. The U.S. Environmental Protection Agency uses models that are not validated for ULV insecticide applications and exposure assumptions to perform their human and ecological risk assessments. Currently, there is no validated model that can accurately predict deposition of insecticides applied using ULV technology for adult mosquito management. In addition, little is known about the deposition and drift of small droplets like those used under conditions encountered during ULV applications. The objective of this study was to perform field studies to measure environmental concentrations of insecticides and to develop a validated model to predict the deposition of ULV insecticides. The final regression model was selected by minimizing the Bayesian Information Criterion and its prediction performance was evaluated using k-fold cross validation. Density of the formulation and the density and CMD interaction coefficients were the largest in the model. The results showed that as density of the formulation decreases, deposition increases. The interaction of density and CMD showed that higher density formulations and larger droplets resulted in greater deposition. These results are supported by the aerosol physics literature. A k-fold cross validation demonstrated that the mean square error of the selected regression model is not biased, and the mean square error and mean square prediction error indicated good predictive ability.

  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. Measured and modeled dry deposition velocities over the ESCOMPTE area

    Science.gov (United States)

    Michou, M.; Laville, P.; Serça, D.; Fotiadi, A.; Bouchou, P.; Peuch, V.-H.

    2005-03-01

    Measurements of the dry deposition velocity of ozone have been made by the eddy correlation method during ESCOMPTE (Etude sur Site pour COntraindre les Modèles de Pollution atmosphérique et de Transport d'Emissions). The strong local variability of natural ecosystems was sampled over several weeks in May, June and July 2001 for four sites with varying surface characteristics. The sites included a maize field, a Mediterranean forest, a Mediterranean shrub-land, and an almost bare soil. Measurements of nitrogen oxide deposition fluxes by the relaxed eddy correlation method have also been carried out at the same bare soil site. An evaluation of the deposition velocities computed by the surface module of the multi-scale Chemistry and Transport Model MOCAGE is presented. This module relies on a resistance approach, with a detailed treatment of the stomatal contribution to the surface resistance. Simulations at the finest model horizontal resolution (around 10 km) are compared to observations. If the seasonal variations are in agreement with the literature, comparisons between raw model outputs and observations, at the different measurement sites and for the specific observing periods, are contrasted. As the simulated meteorology at the scale of 10 km nicely captures the observed situations, the default set of surface characteristics (averaged at the resolution of a grid cell) appears to be one of the main reasons for the discrepancies found with observations. For each case, sensitivity studies have been performed in order to see the impact of adjusting the surface characteristics to the observed ones, when available. Generally, a correct agreement with the observations of deposition velocities is obtained. This advocates for a sub-grid scale representation of surface characteristics for the simulation of dry deposition velocities over such a complex area. Two other aspects appear in the discussion. Firstly, the strong influence of the soil water content to the plant

  7. 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

  8. Geologic characteristics of sediment- and volcanic-hosted disseminated gold deposits - Search for an occurrence model

    Science.gov (United States)

    White, Donald E.; Fournier, Robert O.; Rytuba, James J.; Rye, Robert O.; Cunningham, Charles G.; Berger, Byron R.; Silberman, Miles L.; Bonham, Harold F.; Strachan, Donald G.; Birak, Donald J.; Hawkins, Robert J.; Tooker, Edwin W.; Tooker, Edwin W.

    1985-01-01

    in those data); and (3) assessment of current understanding (as presented in objective 2) toward formulating an empirical ore-occurrence model for this type of deposit. As such, this volume represents a preliminary first step at classification and provides a source of pertinent background information.Readers of this volume will soon discover, however, that full agreement has not yet been achieved in the interpretation of some of the geologic evidence. The resulting variations in tentative occurrence models for these controversial deposits ultimately will be resolved by filling the gaps in information that have already been identified. Thus, this volume does not report a U.S. Geological Survey consensus; the conclusions expressed in each chapter represent the particular interpretations of the various workshop participants.

  9. Application of Concentration-Number and Concentration-Volume Fractal Models to Recognize Mineralized Zones in North Anomaly Iron Ore Deposit, Central Iran / Zastosowanie Modeli Fraktalnych Typu K-L (Koncentracja-Liczba), Oraz K-O (Koncentracja Objętość) Do Rozpoznawania Stref Występowania Surowców Mineralnych W Regionie Złóż Rud Żelaza North Anomaly, W Środkowym Iranie

    Science.gov (United States)

    Afzal, Peyman; Ghasempour, Reza; Mokhtari, Ahmad Reza; Haroni, Hooshang Asadi

    2015-09-01

    Identification of various mineralized zones in an ore deposit is essential for mine planning and design. This study aims to distinguish the different mineralized zones and the wall rock in the Central block of North Anomaly iron ore deposit situated in Bafq (Central Iran) utilizing the concentration-number (C-N) and concentration-volume (C-V) fractal models. The C-N model indicates four mineralized zones described by Fe thresholds of 8%, 21%, and 50%, with zones 50% Fe representing wall rocks and highly mineralized zone, respectively. The C-V model reveals geochemical zones defined by Fe thresholds of 12%, 21%, 43% and 57%, with zones 50% zawartości żelaza, co odpowiada pasmu skalnemu oraz strefie o wysokim stopniu zawartości rudy. Model koncentracja-objętość wskazuje na istnienie stref geochemicznych określonych poprzez progowe wartości zawartości żelaza: 12%, 21%, 43% i 57 % oraz strefy <12%, co odpowiada ścianie skalnej. Obydwa modele stwierdzają obecność stref o wysokim stopniu zawartości surowca w środkowej i zachodniej części złoża. Wyniki walidacji modeli fraktalnych przy użyciu modeli geologicznych wskazują, ze model fraktalny koncentracja-liczba lepiej odwzorowuje obecność stref o wysokiej zawartości rud niż model fraktalny typu koncentracja-objętość.

  10. Total tree, merchantable stem and branch volume models for ...

    African Journals Online (AJOL)

    Total tree, merchantable stem and branch volume models for miombo woodlands of Malawi. Daud J Kachamba, Tron Eid. Abstract. The objective of this study was to develop general (multispecies) models for prediction of total tree, merchantable stem and branch volume including options with diameter at breast height (dbh) ...

  11. Comparison of actual tidal volume in neonatal lung model volume control ventilation using three ventilators.

    Science.gov (United States)

    Toyama, H; Endo, Y; Ejima, Y; Matsubara, M; Kurosawa, S

    2011-07-01

    In neonates, small changes in tidal volumes (V(T)) may lead to complications. Previous studies have shown a significant difference between ventilator-measured tidal volume and tidal volume delivered (actual V(T)). We evaluated the accuracy of three different ventilators to deliver small V(T) during volume-controlled ventilation. We tested Servo 300, 840 ventilator and Evita 4 Neoflow ventilators with lung models simulating normal and injured neonatal lung compliance models. Gas volume delivered from the ventilator into the test circuit (V(TV)) and actual V(T) to the test lung were measured using Ventrak respiration monitors at set V(T) (30 ml). The gas volume increase of the breathing circuit was then calculated. Tidal volumes of the SV300 and PB840 in both lung models were similar to the set V(T) and the actual tidal volumes in the injured model (20.7 ml and 19.8 ml, respectively) were significantly less than that in the normal model (27.4 ml and 23.4 ml). PB840 with circuit compliance compensation could not improve the actual V(T). V(TV) of the EV4N in the normal and the injured models (37.8 ml and 46.6 ml) were markedly increased compared with set V(T), and actual V(T) were similar to set V(T) in the normal and injured model (30.2 ml and 31.9 ml, respectively). EV4N measuring V(T) close to the lung could match actual V(T) to almost the same value as the set V(T) however the gas volume of the breathing circuit was increased. If an accurate value for the patient's actual V(T) is needed, this V(T) must be measured by a sensor located between the Y-piece and the tracheal tube.

  12. Spectral Unmixing Modeling of the Aristarchus Pyroclastic Deposit: Assessing the Eruptive History of Glass-Rich Regional Lunar Pyroclastic Deposits

    Science.gov (United States)

    Jawin, E. R.; Head, J. W., III; Cannon, K.

    2017-12-01

    The Aristarchus pyroclastic deposit in central Oceanus Procellarum is understood to have formed in a gas-rich explosive volcanic eruption, and has been observed to contain abundant volcanic glass. However, the interpreted color (and therefore composition) of the glass has been debated. In addition, previous analyses of the pyroclastic deposit have been performed using lower resolution data than are currently available. In this work, a nonlinear spectral unmixing model was applied to Moon Mineralogy Mapper (M3) data of the Aristarchus plateau to investigate the detailed mineralogic and crystalline nature of the Aristarchus pyroclastic deposit by using spectra of laboratory endmembers including a suite of volcanic glasses returned from the Apollo 15 and 17 missions (green, orange, black beads), as well as synthetic lunar glasses (orange, green, red, yellow). Preliminary results of the M3 unmixing model suggest that spectra of the pyroclastic deposit can be modeled by a mixture composed predominantly of a featureless endmember approximating space weathering and a smaller component of glass. The modeled spectra were most accurate with a synthetic orange glass endmember, relative to the other glasses analyzed in this work. The results confirm that there is a detectable component of glass in the Aristarchus pyroclastic deposit which may be similar to the high-Ti orange glass seen in other regional pyroclastic deposits, with only minimal contributions of other crystalline minerals. The presence of volcanic glass in the pyroclastic deposit, with the low abundance of crystalline material, would support the model that the Aristarchus pyroclastic deposit formed in a long-duration, hawaiian-style fire fountain eruption. No significant detection of devitrified black beads in the spectral modeling results (as was observed at the Apollo 17 landing site in the Taurus-Littrow pyroclastic deposit), suggests the optical density of the eruptive plume remained low throughout the

  13. Coordination number constraint models for hydrogenated amorphous Si deposited by catalytic chemical vapour deposition

    Science.gov (United States)

    Kawahara, Toshio; Tabuchi, Norikazu; Arai, Takashi; Sato, Yoshikazu; Morimoto, Jun; Matsumura, Hideki

    2005-02-01

    We measured structure factors of hydrogenated amorphous Si by x-ray diffraction and analysed the obtained structures using a reverse Monte Carlo (RMC) technique. A small shoulder in the measured structure factor S(Q) was observed on the larger Q side of the first peak. The RMC results with an unconstrained model did not clearly show the small shoulder. Adding constraints for coordination numbers 2 and 3, the small shoulder was reproduced and the agreement with the experimental data became better. The ratio of the constrained coordination numbers was consistent with the ratio of Si-H and Si-H2 bonds which was estimated by the Fourier transformed infrared spectra of the same sample. This shoulder and the oscillation of the corresponding pair distribution function g(r) at large r seem to be related to the low randomness of cat-CVD deposited a-Si:H.

  14. Coordination number constraint models for hydrogenated amorphous Si deposited by catalytic chemical vapour deposition

    International Nuclear Information System (INIS)

    Kawahara, Toshio; Tabuchi, Norikazu; Arai, Takashi; Sato, Yoshikazu; Morimoto, Jun; Matsumura, Hideki

    2005-01-01

    We measured structure factors of hydrogenated amorphous Si by x-ray diffraction and analysed the obtained structures using a reverse Monte Carlo (RMC) technique. A small shoulder in the measured structure factor S(Q) was observed on the larger Q side of the first peak. The RMC results with an unconstrained model did not clearly show the small shoulder. Adding constraints for coordination numbers 2 and 3, the small shoulder was reproduced and the agreement with the experimental data became better. The ratio of the constrained coordination numbers was consistent with the ratio of Si-H and Si-H 2 bonds which was estimated by the Fourier transformed infrared spectra of the same sample. This shoulder and the oscillation of the corresponding pair distribution function g(r) at large r seem to be related to the low randomness of cat-CVD deposited a-Si:H

  15. Airflow structures and nano-particle deposition in a human upper airway model

    Science.gov (United States)

    Zhang, Z.; Kleinstreuer, C.

    2004-07-01

    Considering a human upper airway model, or equivalently complex internal flow conduits, the transport and deposition of nano-particles in the 1-150 nm diameter range are simulated and analyzed for cyclic and steady flow conditions. Specifically, using a commercial finite-volume software with user-supplied programs as a solver, the Euler-Euler approach for the fluid-particle dynamics is employed with a low-Reynolds-number k- ω model for laminar-to-turbulent airflow and the mass transfer equation for dispersion of nano-particles or vapors. Presently, the upper respiratory system consists of two connected segments of a simplified human cast replica, i.e., the oral airways from the mouth to the trachea (Generation G0) and an upper tracheobronchial tree model of G0-G3. Experimentally validated computational fluid-particle dynamics results show the following: (i) transient effects in the oral airways appear most prominently during the decelerating phase of the inspiratory cycle; (ii) selecting matching flow rates, total deposition fractions of nano-size particles for cyclic inspiratory flow are not significantly different from those for steady flow; (iii) turbulent fluctuations which occur after the throat can persist downstream to at least Generation G3 at medium and high inspiratory flow rates (i.e., Qin⩾30 l/min) due to the enhancement of flow instabilities just upstream of the flow dividers; however, the effects of turbulent fluctuations on nano-particle deposition are quite minor in the human upper airways; (iv) deposition of nano-particles occurs to a relatively greater extent around the carinal ridges when compared to the straight tubular segments in the bronchial airways; (v) deposition distributions of nano-particles vary with airway segment, particle size, and inhalation flow rate, where the local deposition is more uniformly distributed for large-size particles (say, dp=100 nm) than for small-size particles (say, dp=1 nm); (vi) dilute 1 nm particle

  16. 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

  17. Atmospheric Energy Deposition Modeling and Inference for Varied Meteoroid Structures

    Science.gov (United States)

    Wheeler, Lorien; Mathias, Donovan; Stokan, Edward; Brown, Peter

    2018-01-01

    Asteroids populations are highly diverse, ranging from coherent monoliths to loosely-bound rubble piles with a broad range of material and compositional properties. These different structures and properties could significantly affect how an asteroid breaks up and deposits energy in the atmosphere, and how much ground damage may occur from resulting blast waves. We have previously developed a fragment-cloud model (FCM) for assessing the atmospheric breakup and energy deposition of asteroids striking Earth. The approach represents ranges of breakup characteristics by combining progressive fragmentation with releases of variable fractions of debris and larger discrete fragments. In this work, we have extended the FCM to also represent asteroids with varied initial structures, such as rubble piles or fractured bodies. We have used the extended FCM to model the Chelyabinsk, Benesov, Kosice, and Tagish Lake meteors, and have obtained excellent matches to energy deposition profiles derived from their light curves. These matches provide validation for the FCM approach, help guide further model refinements, and enable inferences about pre-entry structure and breakup behavior. Results highlight differences in the amount of small debris vs. discrete fragments in matching the various flare characteristics of each meteor. The Chelyabinsk flares were best represented using relatively high debris fractions, while Kosice and Benesov cases were more notably driven by their discrete fragmentation characteristics, perhaps indicating more cohesive initial structures. Tagish Lake exhibited a combination of these characteristics, with lower-debris fragmentation at high altitudes followed by sudden disintegration into small debris in the lower flares. Results from all cases also suggest that lower ablation coefficients and debris spread rates may be more appropriate for the way in which debris clouds are represented in FCM, offering an avenue for future model refinement.

  18. Growth fluctuations in a class of deposition models

    CERN Document Server

    Balazs, M

    2003-01-01

    We compute the growth fluctuations in equilibrium of a wide class of deposition models. These models also serve as general frame to several nearest-neighbor particle jump processes, e.g. the simple exclusion or the zero range process, where our result turns to current fluctuations of the particles. We use martingale technique and coupling methods to show that, rescaled by time, the variance of the growth as seen by a deterministic moving observer has the form |V-C|*D, where V and C is the speed of the observer and the second class particle, respectively, and D is a constant connected to the equilibrium distribution of the model. Our main result is a generalization of Ferrari and Fontes' result for simple exclusion process. Law of large numbers and central limit theorem are also proven. We need some properties of the motion of the second class particle, which are known for simple exclusion and are partly known for zero range processes, and which are proven here for! a type of deposition models and also for a t...

  19. 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.

  20. 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.

  1. Time-specific measurements of energy deposition from radiation fields in simulated sub-micron tissue volumes

    International Nuclear Information System (INIS)

    Famiano, M.A.

    1997-01-01

    A tissue-equivalent spherical proportional counter is used with a modified amplifier system to measure specific energy deposited from a uniform radiation field for short periods of time (∼1 micros to seconds) in order to extrapolate to dose in sub-micron tissue volumes. The energy deposited during these time intervals is compared to biological repair processes occurring within the same intervals after the initial energy deposition. The signal is integrated over a variable collection time which is adjusted with a square-wave pulse. Charge from particle passages is collected on the anode during the period in which the integrator is triggered, and the signal decays quickly to zero after the integrator feedback switch resets; the process repeats for every triggering pulse. Measurements of energy deposited from x rays, 137 Cs gamma rays, and electrons from a 90 Sr/ 90 Y source for various time intervals are taken. Spectral characteristics as a function of charge collection time are observed and frequency plots of specific energy and collection time-interval are presented. In addition, a threshold energy flux is selected for each radiation type at which the formation of radicals (based on current measurements) in mammalian cells equals the rate at which radicals are repaired

  2. Analytical model for a cooperative ballistic deposition in one dimension

    Science.gov (United States)

    Hassan, M. Kamrul; Wessel, Niels; Kurths, Jürgen

    2003-06-01

    We formulate a model for a cooperative ballistic deposition (CBD) process whereby the incoming particles are correlated with those already adsorbed via attractive force. The strength of the correlation is controlled by a tunable parameter a that interpolates the classical car parking problem at a=0, the ballistic deposition at a=1, and the CBD model at a>1. The effects of the correlation in the CBD model are as follows. The jamming coverage q(a) increases with the strength of attraction a due to an ever-increasing tendency of cluster formation. The system almost reaches the closest packing structure as a→∞ but never forms a percolating cluster, which is typical of one-dimensional systems. In the large a regime, the mean cluster size k increases as a1/2. Furthermore, the asymptotic approach towards the closest packing is purely algebraic both with a as q(∞)-q(a)˜a-1/2 and with k as q(∞)-q(k)˜k-1, where q(∞)≃1.

  3. RANS modeling for particle transport and deposition in turbulent duct flows: Near wall model uncertainties

    International Nuclear Information System (INIS)

    Jayaraju, S.T.; Sathiah, P.; Roelofs, F.; Dehbi, A.

    2015-01-01

    Highlights: • Near-wall modeling uncertainties in the RANS particle transport and deposition are addressed in a turbulent duct flow. • Discrete Random Walk (DRW) model and Continuous Random Walk (CRW) model performances are tested. • Several near-wall anisotropic model accuracy is assessed. • Numerous sensitivity studies are performed to recommend a robust, well-validated near-wall model for accurate particle deposition predictions. - Abstract: Dust accumulation in the primary system of a (V)HTR is identified as one of the foremost concerns during a potential accident. Several numerical efforts have focused on the use of RANS methodology to better understand the complex phenomena of fluid–particle interaction at various flow conditions. In the present work, several uncertainties relating to the near-wall modeling of particle transport and deposition are addressed for the RANS approach. The validation analyses are performed in a fully developed turbulent duct flow setup. A standard k − ε turbulence model with enhanced wall treatment is used for modeling the turbulence. For the Lagrangian phase, the performance of a continuous random walk (CRW) model and a discrete random walk (DRW) model for the particle transport and deposition are assessed. For wall bounded flows, it is generally seen that accounting for near wall anisotropy is important to accurately predict particle deposition. The various near-wall correlations available in the literature are either derived from the DNS data or from the experimental data. A thorough investigation into various near-wall correlations and their applicability for accurate particle deposition predictions are assessed. The main outcome of the present work is a well validated turbulence model with optimal near-wall modeling which provides realistic particle deposition predictions

  4. Modeling Accumulated Volume of Landslides Using Remote Sensing and DTM Data

    Directory of Open Access Journals (Sweden)

    Zhengchao Chen

    2014-02-01

    Full Text Available Landslides, like other natural hazards, such as avalanches, floods, and debris flows, may result in a lot of property damage and human casualties. The volume of landslide deposits is a key parameter for landslide studies and disaster relief. Using remote sensing and digital terrain model (DTM data, this paper analyzes errors that can occur in calculating landslide volumes using conventional models. To improve existing models, the mechanisms and laws governing the material deposited by landslides are studied and then the mass balance principle and mass balance line are defined. Based on these ideas, a novel and improved model (Mass Balance Model, MBM is proposed. By using a parameter called the “height adaptor”, MBM translates the volume calculation into an automatic search for the mass balance line within the scope of the landslide. Due to the use of mass balance constraints and the height adaptor, MBM is much more effective and reliable. A test of MBM was carried out for the case of a typical landslide, triggered by the Wenchuan Earthquake of 12 May 2008.

  5. 1987 Oak Ridge model conference: Proceedings: Volume 2, Environmental protection

    International Nuclear Information System (INIS)

    1987-01-01

    See the abstract for Volume I for general information on the conference. Topics discussed in Volume II include data management techiques for environmental protection efforts, the use of models in environmental auditing, in emergency plans, chemical accident emergency response, risk assessment, monitoring of waste sites, air and water monitoring of waste sites, and in training programs

  6. 1987 Oak Ridge model conference: Proceedings: Volume 2, Environmental protection

    Energy Technology Data Exchange (ETDEWEB)

    1987-01-01

    See the abstract for Volume I for general information on the conference. Topics discussed in Volume II include data management techiques for environmental protection efforts, the use of models in environmental auditing, in emergency plans, chemical accident emergency response, risk assessment, monitoring of waste sites, air and water monitoring of waste sites, and in training programs. (TEM)

  7. 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.

  8. Analysis of potential combustion source impacts on acid deposition using an independently derived inventory. Volume I

    Energy Technology Data Exchange (ETDEWEB)

    1983-12-01

    This project had three major objectives. The first objective was to develop a fossil fuel combustion source inventory (NO/sub x/, SO/sub x/, and hydrocarbon emissions) that would be relatively easy to use and update for analyzing the impact of combustion emissions on acid deposition in the eastern United States. The second objective of the project was to use the inventory data as a basis for selection of a number of areas that, by virtue of their importance in the acid rain issue, could be further studied to assess the impact of local and intraregional combustion sources. The third objective was to conduct an analysis of wet deposition monitoring data in the areas under study, along with pertinent physical characteristics, meteorological conditions, and emission patterns of these areas, to investigate probable relationships between local and intraregional combustion sources and the deposition of acidic material. The combustion source emissions inventory has been developed for the eastern United States. It characterizes all important area sources and point sources on a county-by-county basis. Its design provides flexibility and simplicity and makes it uniquely useful in overall analysis of emission patterns in the eastern United States. Three regions with basically different emission patterns have been identified and characterized. The statistical analysis of wet deposition monitoring data in conjunction with emission patterns, wind direction, and topography has produced consistent results for each study area and has demonstrated that the wet deposition in each area reflects the characteristics of the localized area around the monitoring sites (typically 50 to 150 miles). 8 references, 28 figures, 39 tables.

  9. Disc volume reduction with percutaneous nucleoplasty in an animal model.

    Directory of Open Access Journals (Sweden)

    Richard Kasch

    Full Text Available STUDY DESIGN: We assessed volume following nucleoplasty disc decompression in lower lumbar spines from cadaveric pigs using 7.1Tesla magnetic resonance imaging (MRI. PURPOSE: To investigate coblation-induced volume reductions as a possible mechanism underlying nucleoplasty. METHODS: We assessed volume following nucleoplastic disc decompression in pig spines using 7.1-Tesla MRI. Volumetry was performed in lumbar discs of 21 postmortem pigs. A preoperative image data set was obtained, volume was determined, and either disc decompression or placebo therapy was performed in a randomized manner. Group 1 (nucleoplasty group was treated according to the usual nucleoplasty protocol with coblation current applied to 6 channels for 10 seconds each in an application field of 360°; in group 2 (placebo group the same procedure was performed but without coblation current. After the procedure, a second data set was generated and volumes calculated and matched with the preoperative measurements in a blinded manner. To analyze the effectiveness of nucleoplasty, volumes between treatment and placebo groups were compared. RESULTS: The average preoperative nucleus volume was 0.994 ml (SD: 0.298 ml. In the nucleoplasty group (n = 21 volume was reduced by an average of 0.087 ml (SD: 0.110 ml or 7.14%. In the placebo group (n = 21 volume was increased by an average of 0.075 ml (SD: 0.075 ml or 8.94%. The average nucleoplasty-induced volume reduction was 0.162 ml (SD: 0.124 ml or 16.08%. Volume reduction in lumbar discs was significant in favor of the nucleoplasty group (p<0.0001. CONCLUSIONS: Our study demonstrates that nucleoplasty has a volume-reducing effect on the lumbar nucleus pulposus in an animal model. Furthermore, we show the volume reduction to be a coblation effect of nucleoplasty in porcine discs.

  10. 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)

  11. Fixed site neutralization model programmer's manual. Volume II

    International Nuclear Information System (INIS)

    Engi, D.; Chapman, L.D.; Judnick, W.; Blum, R.; Broegler, L.; Lenz, J.; Weinthraub, A.; Ballard, D.

    1979-12-01

    This report relates to protection of nuclear materials at nuclear facilities. This volume presents the source listings for the Fixed Site Neutralization Model and its supporting modules, the Plex Preprocessor and the Data Preprocessor

  12. 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.

  13. 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

  14. Mathematical modelling for dose deposition in photon-therapy

    International Nuclear Information System (INIS)

    Pichard, Teddy

    2016-01-01

    Radiotherapy treatments consists in irradiating the patient with beams of energetic particles (typically photons) targeting the tumor. Such particles are transported through the medium and deposit energy in the medium. This deposited energy is the so called dose, responsible for the biological effect of the radiations. The present work aim to develop numerical methods for dose computation and optimization that are competitive in terms of computational cost and accuracy compared to reference method. The motion of particles is first studied through a system of linear transport equations at the kinetic level. However, solving directly such systems is numerically too costly for medical application. Instead, the moment method is used with a special focus on the Mn models. Those moment equations are non-linear and valid under a condition called realizability. Standard numerical schemes for moment equations are constrained by stability conditions which happen to be very restrictive when the medium contains low density regions. Inconditionally stable numerical schemes adapted to moment equations (preserving the realizability property) are developed. Those schemes are shown to be competitive in terms of computational costs compared to reference approaches. Finally they are applied to in an optimization procedure aiming to maximize the dose in the tumor and to minimize the dose in healthy tissues. (author) [fr

  15. In-Situ Patterning: Selective Area Deposition and Etching. Materials Research Society Symposium Proceedings. Volume 158

    Science.gov (United States)

    1990-11-21

    microelectronics fabriL ...on. Chemical vapor deposition of metals using carbonyls as film precursors has been studied carefully in recent years. For...temperature range that can be studied. For example, it would be difficult to pinpoint a deviation from the Arrhenius law at high temperature as being the...pressure range, the increase of I as a function of p seems to follow a logarithmic law . As a matter of fact, by changing the pressure by two orders of

  16. Atomic layer deposition for semiconductors

    CERN Document Server

    Hwang, Cheol Seong

    2014-01-01

    This edited volume discusses atomic layer deposition (ALD) for all modern semiconductor devices, moving from the basic chemistry of ALD and modeling of ALD processes to sections on ALD for memories, logic devices, and machines.

  17. Modelling deposition of dioxin in Denmark; Modellering af dioxindeposition i Danmark

    Energy Technology Data Exchange (ETDEWEB)

    Mantzius Hansen, K.; Christensen, Jesper H.

    2008-06-15

    We have estimated the deposition of dioxin in Denmark for the years 1970, 1975, 1980, 1985, 1990, 1995, 2000 and 2004 as well as the contribution to air concentrations and depositions from Danish sources relative to the contribution from other European sources. The estimate is based on model simulations with the high-resolution atmospheric chemistry transport model DEHM, where dioxin is modelled as one compound in form of particles. Two different expert emission estimates from EMEP's Meteorological Synthesizing Centre East were used as model input. There are large differences in estimated emissions for some countries from 1990 and onwards, which has a large influence on the simulated depositions. However, it has not been possible to determine which estimate is the most realistic. The concentrations of dioxin in air as well as the depositions increase slightly up to 1980, from where they decrease until 2004. The simulated air concentrations in 2004 are 3,2 fg I-TEQ/m3 and 0,8 fg I-TEQ/m3 for the two emission estimates. The deposited amount of dioxin to Danish land surfaces are 36 g I-TEQ and 9 g I-TEQ for the two emission estimates for 2004. The relative contribution from Danish sources to the deposition of dioxin to Danish land surfaces are 14% and 15% for the two emission estimates for 2004. Despite of large differences in emissions and simulated air concentrations and depositions between the two applied emission estimates, the relative contribution of the Danish sources to the deposition in Denmark does not differ much between the two emission estimates. The contribution of Danish sources to the deposition to Danish land surfaces is estimated to be between 10% and 20%, although there is a large regional variation, from less than 5% to more than 40%. It should be kept in mind that there are sources that are not included in this estimate, such as sources outside Europe and re-emission from previously deposited dioxin, which potentially can give a large

  18. 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)

  19. Model documentation Natural Gas Transmission and Distribution Model of the National Energy Modeling System. Volume 1

    International Nuclear Information System (INIS)

    1996-01-01

    The Natural Gas Transmission and Distribution Model (NGTDM) of the National Energy Modeling System is developed and maintained by the Energy Information Administration (EIA), Office of Integrated Analysis and Forecasting. This report documents the archived version of the NGTDM that was used to produce the natural gas forecasts presented in the Annual Energy Outlook 1996, (DOE/EIA-0383(96)). The purpose of this report is to provide a reference document for model analysts, users, and the public that defines the objectives of the model, describes its basic approach, and provides detail on the methodology employed. Previously this report represented Volume I of a two-volume set. Volume II reported on model performance, detailing convergence criteria and properties, results of sensitivity testing, comparison of model outputs with the literature and/or other model results, and major unresolved issues

  20. Model documentation Natural Gas Transmission and Distribution Model of the National Energy Modeling System. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-02-26

    The Natural Gas Transmission and Distribution Model (NGTDM) of the National Energy Modeling System is developed and maintained by the Energy Information Administration (EIA), Office of Integrated Analysis and Forecasting. This report documents the archived version of the NGTDM that was used to produce the natural gas forecasts presented in the Annual Energy Outlook 1996, (DOE/EIA-0383(96)). The purpose of this report is to provide a reference document for model analysts, users, and the public that defines the objectives of the model, describes its basic approach, and provides detail on the methodology employed. Previously this report represented Volume I of a two-volume set. Volume II reported on model performance, detailing convergence criteria and properties, results of sensitivity testing, comparison of model outputs with the literature and/or other model results, and major unresolved issues.

  1. Modeling truck traffic volume growth congestion.

    Science.gov (United States)

    2009-05-01

    Modeling of the statewide transportation system is an important element in understanding issues and programming of funds to thwart potential congestion. As Alabama grows its manufacturing economy, the number of heavy vehicles traversing its highways ...

  2. 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

  3. 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

  4. Spatial Economics Model Predicting Transport Volume

    Directory of Open Access Journals (Sweden)

    Lu Bo

    2016-10-01

    Full Text Available It is extremely important to predict the logistics requirements in a scientific and rational way. However, in recent years, the improvement effect on the prediction method is not very significant and the traditional statistical prediction method has the defects of low precision and poor interpretation of the prediction model, which cannot only guarantee the generalization ability of the prediction model theoretically, but also cannot explain the models effectively. Therefore, in combination with the theories of the spatial economics, industrial economics, and neo-classical economics, taking city of Zhuanghe as the research object, the study identifies the leading industry that can produce a large number of cargoes, and further predicts the static logistics generation of the Zhuanghe and hinterlands. By integrating various factors that can affect the regional logistics requirements, this study established a logistics requirements potential model from the aspect of spatial economic principles, and expanded the way of logistics requirements prediction from the single statistical principles to an new area of special and regional economics.

  5. Increased brain iron deposition is a risk factor for brain atrophy in patients with haemodialysis: a combined study of quantitative susceptibility mapping and whole brain volume analysis.

    Science.gov (United States)

    Chai, Chao; Zhang, Mengjie; Long, Miaomiao; Chu, Zhiqiang; Wang, Tong; Wang, Lijun; Guo, Yu; Yan, Shuo; Haacke, E Mark; Shen, Wen; Xia, Shuang

    2015-08-01

    To explore the correlation between increased brain iron deposition and brain atrophy in patients with haemodialysis and their correlation with clinical biomarkers and neuropsychological test. Forty two patients with haemodialysis and forty one age- and gender-matched healthy controls were recruited in this prospective study. 3D whole brain high resolution T1WI and susceptibility weighted imaging were scanned on a 3 T MRI system. The brain volume was analyzed using voxel-based morphometry (VBM) in patients and to compare with that of healthy controls. Quantitative susceptibility mapping was used to measure and compare the susceptibility of different structures between patients and healthy controls. Correlation analysis was used to investigate the relationship between the brain volume, iron deposition and neuropsychological scores. Stepwise multiple regression analysis was used to explore the effect of clinical biomarkers on the brain volumes in patients. Compared with healthy controls, patients with haemodialysis showed decreased volume of bilateral putamen and left insular lobe (All P brain iron deposition is negatively correlated with the decreased volume of bilateral putamen (P brain iron deposition and dialysis duration was risk factors for brain atrophy in patients with haemodialysis. The decreased gray matter volume of the left insular lobe was correlated with neurocognitive impairment.

  6. Biological modelling of fuzzy target volumes in 3D radiotherapy

    International Nuclear Information System (INIS)

    Levegruen, S.; Kampen, M. van; Waschek, T.; Engenhart, R.; Schlegel, W.

    1995-01-01

    Purpose/Objective: The outcome of each radiotherapy depends critically on the optimal choice of the target volume. The goal of the radiotherapist is to include all tumor spread at the same time as saving as much healthy tissue as possible. Even when the information of all imaging modalities is combined, the diagnostic techniques are not sensitive and specific enough to visualize all microscopic tumor cell spread. Due to this lack of information there is room for different interpretations concerning the extend of the target volume, leading to a fuzzy target volume. The aim of this work is to develop a model to score different target volume boundaries within the region of diagnostic uncertainty in terms of tumor control probability (TCP) and normal tissue complication probabilities (NTCP). Materials and Methods: In order to assess the region of diagnostic uncertainty, the radiotherapist defines interactively a minimal planning target volume that absolutely must be irradiated according to the diagnostic information available and a maximal planning target volume outside which no tumor cell spread is expected. For the NTCP calculation we use the Lyman 4 parameter model to estimate the response of an organ at risk to a uniform partial volume irradiation. The TCP calculation is based on the Poisson model of cell killing. The TCP estimation depends not only on volume, dose, clonogenic cell density and the α parameter of the linear quadratic model but also on the probability to find clonogenic cells in the considered volume. Inside the minimal PTV this probability is 1, outside the maximal PTV it is 0. Therefore all voxels inside the minimal PTV are assigned the value of 1 with respect to the target volume, all voxels outside the maximal PTV the value of 0. For voxels in the region of uncertainty in between, a 3D linear interpolation is performed. Here we assume the probability to follow the interpolated values. Starting with the minimal PTV, the expected gain in TCP and

  7. Mathematical models for volume rendering and neutron transport

    International Nuclear Information System (INIS)

    Max, N.

    1994-09-01

    This paper reviews several different models for light interaction with volume densities of absorbing, glowing, reflecting, or scattering material. They include absorption only, glow only, glow and absorption combined, single scattering of external illumination, and multiple scattering. The models are derived from differential equations, and illustrated on a data set representing a cloud. They are related to corresponding models in neutron transport. The multiple scattering model uses an efficient method to propagate the radiation which does not suffer from the ray effect

  8. The relationship between open volume defects and deposition conditions of superconducting thin-film YBa sub 2 Cu sub 3 O sub 7 sub - sub x

    CERN Document Server

    Zhou, X Y; Jiang, H; Bauer-Kugelmann, W; Duffy, J A; Koegel, G; Triftshaeuser, W

    1997-01-01

    The relationship between the open volume defects and the deposition conditions of superconducting thin-film YBa sub 2 Cu sub 3 O sub 7 sub - sub x was studied by the position lifetime technique. Using a low-energy pulsed positron system, positron lifetime as a function of implantation energy was measured on epitaxial superconducting thin-film YBa sub 2 Cu sub 3 O sub 7 sub - sub x deposited on yttrium stabilized cubic zirconia substrates (YSZ) with pulsed laser deposition in a partial pressure of air under different conditions. The results show that the type of open volume defect is independent of deposition conditions such as the substrate temperature, T sub s , and the air pressure, P sub a. The defect concentration increases with decreasing T sub s and increasing P sub a. (author). Letter-to-the-editor

  9. Morphological modeling of terrains and volume data

    CERN Document Server

    Comic, Lidija; Magillo, Paola; Iuricich, Federico

    2014-01-01

    This book describes the mathematical background behind discrete approaches to morphological analysis of scalar fields, with a focus on Morse theory and on the discrete theories due to Banchoff and Forman. The algorithms and data structures presented are used for terrain modeling and analysis, molecular shape analysis, and for analysis or visualization of sensor and simulation 3D data sets. It covers a variety of application domains including geography, geology, environmental sciences, medicine and biology. The authors classify the different approaches to morphological analysis which are all ba

  10. Development of an ash particle deposition model considering build-up and removal mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Strandstroem, Kjell; Mueller, Christian; Hupa, Mikko [Aabo Akademi Process Chemistry Centre, Biskopsgatan 8, FI-20500 Aabo (Finland)

    2007-12-15

    Slagging and fouling on heat exchanger surfaces in power boilers fired with fossil fuels and fuel mixtures has a significant influence on boiler efficiency and availability. Mathematical modelling is since long considered a suitable method to assist boiler operators to determine optimized operating conditions for an existing furnace. The ultimate goal in ash deposition prediction is hereby the determination of the total amount of material deposited and hence the determination of the total reduction in efficiency. Depending on the fuels fired the total deposited mass is a combination of ash particle deposition and ash particle erosion due to non-sticky particles. The novel ash particle deposition model presented in this work considers deposition of sticky ash particles, cleansing of deposit by non-sticky sand particles and sticking of sand due to contact with sticky ash. The steady-state modelling results for the total amount of ash deposited on the deposition probe of an entrained flow reactor presented in this work agree well with the experimental data. Only at very high fractions of sand added as non-sticky material, a significant influence of the sand on the overall mass deposited was found. Since the model considers sticking of non-sticking sand due to contact with sticky ash, the fraction of sand deposited on the probe was especially studied. Using a correction factor to consider the influence of operating time on the steady-state simulations led to good agreement between simulations and experimental data. (author)

  11. Development of an ash particle deposition model considering build-up and removal mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Kjell Strandstroem; Christian Muellera; Mikko Hupa [Abo Akademi Process Chemistry Centre, Abo (Finland)

    2007-12-15

    Slagging and fouling on heat exchanger surfaces in power boilers fired with fossil fuels and fuel mixtures has a significant influence on boiler efficiency and availability. Mathematical modelling has long been considered a suitable method to assist boiler operators to determine optimized operating conditions for an existing furnace. The ultimate goal in ash deposition prediction is hereby the determination of the total amount of material deposited and hence the determination of the total reduction in efficiency. Depending on the fuels fired the total deposited mass is a combination of ash particle deposition and ash particle erosion due to non-sticky particles. The novel ash particle deposition model presented in this work considers deposition of sticky ash particles, cleansing of deposit by non-sticky sand particles and sticking of sand due to contact with sticky ash. The steady-state modelling results for the total amount of ash deposited on the deposition probe of an entrained flow reactor presented in this work agree well with the experimental data. Only at very high fractions of sand added as non-sticky material, a significant influence of the sand on the overall mass deposited was found. Since the model considers sticking of non-sticking sand due to contact with sticky ash, the fraction of sand deposited on the probe was especially studied. Using a correction factor to consider the influence of operating time on the steady-state simulations led to good agreement between simulations and experimental data. 12 refs., 10 figs.

  12. Sediment-Hosted Zinc-Lead Deposits of the World - Database and Grade and Tonnage Models

    Science.gov (United States)

    Singer, Donald A.; Berger, Vladimir I.; Moring, Barry C.

    2009-01-01

    This report provides information on sediment-hosted zinc-lead mineral deposits based on the geologic settings that are observed on regional geologic maps. The foundation of mineral-deposit models is information about known deposits. The purpose of this publication is to make this kind of information available in digital form for sediment-hosted zinc-lead deposits. Mineral-deposit models are important in exploration planning and quantitative resource assessments: Grades and tonnages among deposit types are significantly different, and many types occur in different geologic settings that can be identified from geologic maps. Mineral-deposit models are the keystone in combining the diverse geoscience information on geology, mineral occurrences, geophysics, and geochemistry used in resource assessments and mineral exploration. Too few thoroughly explored mineral deposits are available in most local areas for reliable identification of the important geoscience variables, or for robust estimation of undiscovered deposits - thus, we need mineral-deposit models. Globally based deposit models allow recognition of important features because the global models demonstrate how common different features are. Well-designed and -constructed deposit models allow geologists to know from observed geologic environments the possible mineral-deposit types that might exist, and allow economists to determine the possible economic viability of these resources in the region. Thus, mineral-deposit models play the central role in transforming geoscience information to a form useful to policy makers. This publication contains a computer file of information on sediment-hosted zinc-lead deposits from around the world. It also presents new grade and tonnage models for nine types of these deposits and a file allowing locations of all deposits to be plotted in Google Earth. The data are presented in FileMaker Pro, Excel and text files to make the information available to as many as possible. The

  13. An operator calculus for surface and volume modeling

    Science.gov (United States)

    Gordon, W. J.

    1984-01-01

    The mathematical techniques which form the foundation for most of the surface and volume modeling techniques used in practice are briefly described. An outline of what may be termed an operator calculus for the approximation and interpolation of functions of more than one independent variable is presented. By considering the linear operators associated with bivariate and multivariate interpolation/approximation schemes, it is shown how they can be compounded by operator multiplication and Boolean addition to obtain a distributive lattice of approximation operators. It is then demonstrated via specific examples how this operator calculus leads to practical techniques for sculptured surface and volume modeling.

  14. 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

  15. 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.

  16. 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.

  17. Metallogenic model for continental volcanic-type rich and large uranium deposits

    International Nuclear Information System (INIS)

    Chen Guihua

    1998-01-01

    A metallogenic model for continental volcanic-type rich and large/super large uranium deposits has been established on the basis of analysis of occurrence features and ore-forming mechanism of some continental volcanic-type rich and large/super large uranium deposits in the world. The model proposes that uranium-enriched granite or granitic basement is the foundation, premetallogenic polycyclic and multistage volcanic eruptions are prerequisites, intense tectonic-extensional environment is the key for the ore formation, and relatively enclosed geologic setting is the reliable protection condition of the deposit. By using the model the author explains the occurrence regularities of some rich and large/super large uranium deposits such as Strelichof uranium deposit in Russia, Dornot uranium deposit in Mongolia, Olympic Dam Cu-U-Au-REE deposit in Australia, uranium deposit No.460 and Zhoujiashan uranium deposit in China, and then compares the above deposits with a large poor uranium deposit No.661 as well

  18. Geology of proximal, small-volume trachyte-trachyandesite pyroclastic flows and associated surge deposits, Roccamonfina volcano, Italy

    Science.gov (United States)

    Giannetti, Bernardino

    1998-01-01

    This paper describes the 232 ka B.P. MTTT trachyte-trachyandesite pyroclastic succession of Roccamonfina volcano. This small-volume, proximal sequence crops out along Mulino di Sotto, Paratone, and Pisciariello ravines in the southwest sector of the central caldera, and covers a minimum extent of 3.5 km 2 area. It is made up of seven pyroclastic flows and pyroclastic surge units consisting of trachytic ash matrix containing juvenile trachyandesitic scoria and dense lava fragments, pumice clasts of uncertain trachyandesite, and a foreign trachyandesitic lithic facies. Two stratigraphic markers allow correlation of the units. No paleosoils and Plinian fallout have been observed at the base and within the succession. Some lateral grading of scoria and lithic clasts suggests that MTTT derived from three distinct source vents. The sequence consists of a basal ash flow passing laterally to laminated surge deposits (Unit A). This is overlain by a reversely graded scoria and pumice lapilli flow (Unit B) which is in turn overlain by a thinly cross-stratified scoria lapilli surge (Unit C). Unit C is capped by a prominent ash-and-scoria flow (Unit D). A ground layer (Marker MK1) divides Unit D from a massive ignimbrite which grades upcurrent to sand-wave surge deposits (Unit E). Another ground layer (Marker MK2) separates Unit E from Unit F. This unit consists of a basal ignimbrite passing laterally to bedded surge deposits with convolute structures (subunit Fl), and grading upcurrent to a subhorizontally plane-laminated ash cloud (subunit F2) containing near the top a layer of millimetric lithic clasts embedded in fine ash. The succession is closed by the pyroclastic flow Unit G. Surge Unit C can be interpreted in terms of vertical gradients in turbulence, particle concentration, and velocity during flowage, whereas the bedded surge parts present in the massive deposits of Units A and E-F1 can be related to abrupt changes of velocity down the steep slopes of ravines. Reverse

  19. Multi-model study of HTAP II on sulfur and nitrogen deposition

    Science.gov (United States)

    Tan, Jiani; Fu, Joshua S.; Dentener, Frank; Sun, Jian; Emmons, Louisa; Tilmes, Simone; Sudo, Kengo; Flemming, Johannes; Eiof Jonson, Jan; Gravel, Sylvie; Bian, Huisheng; Davila, Yanko; Henze, Daven K.; Lund, Marianne T.; Kucsera, Tom; Takemura, Toshihiko; Keating, Terry

    2018-05-01

    This study uses multi-model ensemble results of 11 models from the second phase of Task Force Hemispheric Transport of Air Pollution (HTAP II) to calculate the global sulfur (S) and nitrogen (N) deposition in 2010. Modeled wet deposition is evaluated with observation networks in North America, Europe and East Asia. The modeled results agree well with observations, with 76-83 % of stations being predicted within ±50 % of observations. The models underestimate SO42-, NO3- and NH4+ wet depositions in some European and East Asian stations but overestimate NO3- wet deposition in the eastern United States. Intercomparison with previous projects (PhotoComp, ACCMIP and HTAP I) shows that HTPA II has considerably improved the estimation of deposition at European and East Asian stations. Modeled dry deposition is generally higher than the inferential data calculated by observed concentration and modeled velocity in North America, but the inferential data have high uncertainty, too. The global S deposition is 84 Tg(S) in 2010, with 49 % in continental regions and 51 % in the ocean (19 % of which coastal). The global N deposition consists of 59 Tg(N) oxidized nitrogen (NOy) deposition and 64 Tg(N) reduced nitrogen (NHx) deposition in 2010. About 65 % of N is deposited in continental regions, and 35 % in the ocean (15 % of which coastal). The estimated outflow of pollution from land to ocean is about 4 Tg(S) for S deposition and 18 Tg(N) for N deposition. Comparing our results to the results in 2001 from HTAP I, we find that the global distributions of S and N deposition have changed considerably during the last 10 years. The global S deposition decreases 2 Tg(S) (3 %) from 2001 to 2010, with significant decreases in Europe (5 Tg(S) and 55 %), North America (3 Tg(S) and 29 %) and Russia (2 Tg(S) and 26 %), and increases in South Asia (2 Tg(S) and 42 %) and the Middle East (1 Tg(S) and 44 %). The global N deposition increases by 7 Tg(N) (6 %), mainly contributed by South Asia

  20. Depositional sequence analysis and sedimentologic modeling for improved prediction of Pennsylvanian reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Watney, W.L.

    1994-12-01

    Reservoirs in the Lansing-Kansas City limestone result from complex interactions among paleotopography (deposition, concurrent structural deformation), sea level, and diagenesis. Analysis of reservoirs and surface and near-surface analogs has led to developing a {open_quotes}strandline grainstone model{close_quotes} in which relative sea-level stabilized during regressions, resulting in accumulation of multiple grainstone buildups along depositional strike. Resulting stratigraphy in these carbonate units are generally predictable correlating to inferred topographic elevation along the shelf. This model is a valuable predictive tool for (1) locating favorable reservoirs for exploration, and (2) anticipating internal properties of the reservoir for field development. Reservoirs in the Lansing-Kansas City limestones are developed in both oolitic and bioclastic grainstones, however, re-analysis of oomoldic reservoirs provides the greatest opportunity for developing bypassed oil. A new technique, the {open_quotes}Super{close_quotes} Pickett crossplot (formation resistivity vs. porosity) and its use in an integrated petrophysical characterization, has been developed to evaluate extractable oil remaining in these reservoirs. The manual method in combination with 3-D visualization and modeling can help to target production limiting heterogeneities in these complex reservoirs and moreover compute critical parameters for the field such as bulk volume water. Application of this technique indicates that from 6-9 million barrels of Lansing-Kansas City oil remain behind pipe in the Victory-Northeast Lemon Fields. Petroleum geologists are challenged to quantify inferred processes to aid in developing rationale geologically consistent models of sedimentation so that acceptable levels of prediction can be obtained.

  1. 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.

  2. Temporal validation for landsat-based volume estimation model

    Science.gov (United States)

    Renaldo J. Arroyo; Emily B. Schultz; Thomas G. Matney; David L. Evans; Zhaofei Fan

    2015-01-01

    Satellite imagery can potentially reduce the costs and time associated with ground-based forest inventories; however, for satellite imagery to provide reliable forest inventory data, it must produce consistent results from one time period to the next. The objective of this study was to temporally validate a Landsat-based volume estimation model in a four county study...

  3. The Utilization of Remotely Sensed Data to Analyze the Estimated Volume of Pyroclastic Deposits and Morphological Changes Caused by the 2010-2015 Eruption of Sinabung Volcano, North Sumatra, Indonesia

    Science.gov (United States)

    Yulianto, Fajar; Suwarsono; Sofan, Parwati

    2016-08-01

    In this research, remotely sensed data has been used to estimate the volume of pyroclastic deposits and analyze morphological changes that have resulted from the eruption of Sinabung volcano. Topographic information was obtained from these data and used for rapid mapping to assist in the emergency response. Topographic information and change analyses (pre- and syn- eruption) were conducted using digital elevation models (DEMs) for the period 2010-2015. Advanced spaceborne thermal emission and reflection radiometer (ASTER) global digital elevation model (GDEM) data from 2009 were used to generate the initial DEMs for the condition prior to the eruption of 2010. Satellite pour l'observation de la terre 6 (SPOT 6) stereo images acquired on 21 June 2015 and were used to make a DEM for that time. The results show that the estimated total volume of lava and pyroclastic deposits, produced during the period 2010 to mid-2015 is approximately 2.8 × 108 m3. This estimated volume of pyroclastic deposits can be used to predict the magnitude of future secondary lahar hazards, which are also related to the capacity of rivers in the area. Morphological changes are illustrated using cross-sectional analysis of the deposits, which are currently deposited to the east, southeast and south of the volcano. Such analyses can also help in forecasting the direction of the future flow hazards. The remote sensing and analysis methods used at Sinabung can also be applied at other volcanoes and to assess the threats of other types of hazards such as landslides and land subsidence.

  4. A climatological model for risk computations incorporating site- specific dry deposition influences

    International Nuclear Information System (INIS)

    Droppo, J.G. Jr.

    1991-07-01

    A gradient-flux dry deposition module was developed for use in a climatological atmospheric transport model, the Multimedia Environmental Pollutant Assessment System (MEPAS). The atmospheric pathway model computes long-term average contaminant air concentration and surface deposition patterns surrounding a potential release site incorporating location-specific dry deposition influences. Gradient-flux formulations are used to incorporate site and regional data in the dry deposition module for this atmospheric sector-average climatological model. Application of these formulations provide an effective means of accounting for local surface roughness in deposition computations. Linkage to a risk computation module resulted in a need for separate regional and specific surface deposition computations. 13 refs., 4 figs., 2 tabs

  5. A comprehensive mathematical model of microscopic dose deposition in photodynamic therapy

    International Nuclear Information System (INIS)

    Kang-Hsin Wang, Ken; Mitra, Soumya; Foster, Thomas H.

    2007-01-01

    vessels and shows that treatment-limiting 3 O 2 depletion is induced at fluence rates as low as 10 mW cm -2 . These calculations also demonstrate that intercapillary heterogeneity of photosensitizer contributes significantly to the distribution of photodynamic dose. This more rigorous mathematical model enables comparison with experimentally observable, volume-averaged quantities such as SO 2 and the loss of sensitizer fluorescence through bleaching that have not been included in previous analyses. Further, it establishes some of the intrinsic limitations of such measurements. Specifically, our simulations demonstrate that tissue measurements of SO 2 and of photobleaching are necessarily insensitive to microscopic heterogeneity of photodynamic dose deposition and are sensitive to intercapillary spacing. Because prior knowledge of intercapillary distances in tumors is generally unavailable, these measurements must be interpreted with caution. We anticipate that this model will make useful dosimetry predictions that should inform optimal treatment conditions and improve current clinical protocols

  6. Computationally efficient analysis of particle transport and deposition in a human whole-lung-airway model. Part I: Theory and model validation.

    Science.gov (United States)

    Kolanjiyil, Arun V; Kleinstreuer, Clement

    2016-12-01

    Computational predictions of aerosol transport and deposition in the human respiratory tract can assist in evaluating detrimental or therapeutic health effects when inhaling toxic particles or administering drugs. However, the sheer complexity of the human lung, featuring a total of 16 million tubular airways, prohibits detailed computer simulations of the fluid-particle dynamics for the entire respiratory system. Thus, in order to obtain useful and efficient particle deposition results, an alternative modeling approach is necessary where the whole-lung geometry is approximated and physiological boundary conditions are implemented to simulate breathing. In Part I, the present new whole-lung-airway model (WLAM) represents the actual lung geometry via a basic 3-D mouth-to-trachea configuration while all subsequent airways are lumped together, i.e., reduced to an exponentially expanding 1-D conduit. The diameter for each generation of the 1-D extension can be obtained on a subject-specific basis from the calculated total volume which represents each generation of the individual. The alveolar volume was added based on the approximate number of alveoli per generation. A wall-displacement boundary condition was applied at the bottom surface of the first-generation WLAM, so that any breathing pattern due to the negative alveolar pressure can be reproduced. Specifically, different inhalation/exhalation scenarios (rest, exercise, etc.) were implemented by controlling the wall/mesh displacements to simulate realistic breathing cycles in the WLAM. Total and regional particle deposition results agree with experimental lung deposition results. The outcomes provide critical insight to and quantitative results of aerosol deposition in human whole-lung airways with modest computational resources. Hence, the WLAM can be used in analyzing human exposure to toxic particulate matter or it can assist in estimating pharmacological effects of administered drug-aerosols. As a practical

  7. An analytical model for particulate deposition on vertical heat transfer surfaces in a boiling environment

    International Nuclear Information System (INIS)

    Keefer, R.H.; Rider, J.L.; Waldman, L.A.

    1993-01-01

    A frequent problem in heat exchange equipment is the deposition of particulates entrained in the working fluid onto heat transfer surfaces. These deposits increase the overall heat transfer resistance and can significantly degrade the performance of the heat exchanger. Accurate prediction of the deposition rate is necessary to ensure that the design and specified operating conditions of the heat exchanger adequately address the effects of this deposit layer. Although the deposition process has been studied in considerable detail, much of the work has focused on investigating individual aspects of the deposition process. This paper consolidates this previous research into a mechanistically based analytical prediction model for particulate deposition from a boiling liquid onto vertical heat transfer surfaces. Consistent with the well known Kern-Seaton approach, the model postulates net particulate accumulation to depend on the relative contributions of deposition and reentrainment processes. Mechanisms for deposition include boiling, momentum, and diffusion effects. Reentrainment is presumed to occur via an intermittent erosion process, with the energy for particle removal being supplied by turbulent flow instabilities. The contributions of these individual mechanisms are integrated to obtain a single equation for the deposit thickness versus time. The validity of the resulting model is demonstrated by comparison with data published in the open literature. Model estimates show good agreement with data obtained over a range of thermal-hydraulic conditions in both flow and pool boiling environments. The utility of the model in performing parametric studies (e.g. to determine the effect of flow velocity on net deposition) is also demonstrated. The initial success of the model suggests that it could prove useful in establishing a range of heat exchanger. operating conditions to minimize deposition

  8. 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.

  9. PREDICTIONS OF DISPERSION AND DEPOSITION OF FALLOUT FROM NUCLEAR TESTING USING THE NOAA-HYSPLIT METEOROLOGICAL MODEL

    Science.gov (United States)

    Moroz, Brian E.; Beck, Harold L.; Bouville, André; Simon, Steven L.

    2013-01-01

    The NOAA Hybrid Single-Particle Lagrangian Integrated Trajectory Model (HYSPLIT) was evaluated as a research tool to simulate the dispersion and deposition of radioactive fallout from nuclear tests. Model-based estimates of fallout can be valuable for use in the reconstruction of past exposures from nuclear testing, particularly, where little historical fallout monitoring data is available. The ability to make reliable predictions about fallout deposition could also have significant importance for nuclear events in the future. We evaluated the accuracy of the HYSPLIT-predicted geographic patterns of deposition by comparing those predictions against known deposition patterns following specific nuclear tests with an emphasis on nuclear weapons tests conducted in the Marshall Islands. We evaluated the ability of the computer code to quantitatively predict the proportion of fallout particles of specific sizes deposited at specific locations as well as their time of transport. In our simulations of fallout from past nuclear tests, historical meteorological data were used from a reanalysis conducted jointly by the National Centers for Environmental Prediction (NCEP) and the National Center for Atmospheric Research (NCAR). We used a systematic approach in testing the HYSPLIT model by simulating the release of a range of particles sizes from a range of altitudes and evaluating the number and location of particles deposited. Our findings suggest that the quantity and quality of meteorological data are the most important factors for accurate fallout predictions and that when satisfactory meteorological input data are used, HYSPLIT can produce relatively accurate deposition patterns and fallout arrival times. Furthermore, when no other measurement data are available, HYSPLIT can be used to indicate whether or not fallout might have occurred at a given location and provide, at minimum, crude quantitative estimates of the magnitude of the deposited activity. A variety of

  10. Predictions of dispersion and deposition of fallout from nuclear testing using the NOAA-HYSPLIT meteorological model.

    Science.gov (United States)

    Moroz, Brian E; Beck, Harold L; Bouville, André; Simon, Steven L

    2010-08-01

    The NOAA Hybrid Single-Particle Lagrangian Integrated Trajectory Model (HYSPLIT) was evaluated as a research tool to simulate the dispersion and deposition of radioactive fallout from nuclear tests. Model-based estimates of fallout can be valuable for use in the reconstruction of past exposures from nuclear testing, particularly where little historical fallout monitoring data are available. The ability to make reliable predictions about fallout deposition could also have significant importance for nuclear events in the future. We evaluated the accuracy of the HYSPLIT-predicted geographic patterns of deposition by comparing those predictions against known deposition patterns following specific nuclear tests with an emphasis on nuclear weapons tests conducted in the Marshall Islands. We evaluated the ability of the computer code to quantitatively predict the proportion of fallout particles of specific sizes deposited at specific locations as well as their time of transport. In our simulations of fallout from past nuclear tests, historical meteorological data were used from a reanalysis conducted jointly by the National Centers for Environmental Prediction (NCEP) and the National Center for Atmospheric Research (NCAR). We used a systematic approach in testing the HYSPLIT model by simulating the release of a range of particle sizes from a range of altitudes and evaluating the number and location of particles deposited. Our findings suggest that the quantity and quality of meteorological data are the most important factors for accurate fallout predictions and that, when satisfactory meteorological input data are used, HYSPLIT can produce relatively accurate deposition patterns and fallout arrival times. Furthermore, when no other measurement data are available, HYSPLIT can be used to indicate whether or not fallout might have occurred at a given location and provide, at minimum, crude quantitative estimates of the magnitude of the deposited activity. A variety of

  11. 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

  12. A volume flexible inventory model with trapezoidal demand under inflation

    Directory of Open Access Journals (Sweden)

    kapil mehrotra

    2014-02-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Abstract   This article experiment. Further, the effects of different parameters are analysed by performing sensitivity analyses on the optimal policy. explores an economic production quantity model (EPQ model for deteriorating items with time-dependent demand following trapezoidal pattern taking the volume flexibility into account. We have also considered the inflation and time value of money. The solution of the model aims at determining the optimal production run-time in order to maximize the profit. The model is also illustrated by means of numerical

  13. Model for the radionuclide measurement of ascitic fluid volumes

    International Nuclear Information System (INIS)

    Kaplan, W.D.; Davis, M.A.; Uren, R.F.; Wisotsky, T.; LaTegola, M.

    1978-01-01

    Technetium-99m phytate colloids formed in vitro and in vivo were examined as radioindicators for estimation of the volume of third-space fluid in an ovarian ascites model using C3HeB/FeJ mice. In double-label experiments, the accuracy of the colloids for dilution analysis was found to be equal or superior to that of I-125 HSA. Sampling times 3 to 5 min after intraperitoneal administration were found to produce the best volume estimates. Four needle-stopcock assemblies inserted sequentially into the quadrants of the peritoneal cavity were used for administration and sampling of the radioindicators. The stopcocks could be closed to prevent leakage of ascitic fluid during the procedure. In contrast to radiolabeled albumin, Tc-99m phytate colloids have clinical use for simultaneous imaging of radiotracer migration to assess potential occlusion of diaphragmatic lymphatics by neoplastic cells, and for dilution analysis to estimate volume of ascitic fluid

  14. Development of a hip joint model for finite volume simulations.

    Science.gov (United States)

    Cardiff, P; Karač, A; FitzPatrick, D; Ivanković, A

    2014-01-01

    This paper establishes a procedure for numerical analysis of a hip joint using the finite volume method. Patient-specific hip joint geometry is segmented directly from computed tomography and magnetic resonance imaging datasets and the resulting bone surfaces are processed into a form suitable for volume meshing. A high resolution continuum tetrahedral mesh has been generated, where a sandwich model approach is adopted; the bones are represented as a stiffer cortical shells surrounding more flexible cancellous cores. Cartilage is included as a uniform thickness extruded layer and the effect of layer thickness is investigated. To realistically position the bones, gait analysis has been performed giving the 3D positions of the bones for the full gait cycle. Three phases of the gait cycle are examined using a finite volume based custom structural contact solver implemented in open-source software OpenFOAM.

  15. 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.

  16. Reconstruction of eroded and deposited sediment volumes in the floodplains of the embanked River Waal, the Netherlands, for the period 1650 - 1850 AD

    Science.gov (United States)

    Hobo, Noortje; Makaske, Bart; Middelkoop, Hans

    2010-05-01

    The embanked floodplains of the River Waal developed as a result of stepwise downstream migration of meander bends between confining dykes. Accretion in the upstream limb of the outer bend - enhanced by groynes and trees - and erosion in the downstream limb have resulted in a series of successively developed sand bars, separated by secondary channels. On top of the sand bars and the secondary channel fills, fine-grained overbank sediments were deposited. Downstream migration ceased around 1850 AD, when the river bed was fixed by large-scale construction of groynes, and only overbank deposition continued. Eroded and deposited sediment volumes associated with downstream migration are affected by human activities. Goal of the present research is to estimate a sediment budget for a 12-km-long section along the River Waal, by quantifying the amount of erosion and deposition. We estimated these volumes for time slices of 50 years, between 1650 and 1850 AD, in order to be able to assess the variable impact of human interference during this period. To estimate erosion, we created geomorphological maps for all time slices, based on maps dating from the 17th century to present. In these maps, distinction is made between sand bars, residual channels, and older deposits (all sediments deposited before 1650 AD). Comparison between all maps allowed us to calculate the eroded area per time slice. Eroded volumes were hence estimated by multiplying the eroded area by the average river depth at that period, which is assumed to be the erosion depth. For estimation of deposition we used lithological cross-sections. These cross-sections are positioned such that every sand bar and every residual channel is represented in at least one cross-section. In every cross-section isochrones were drawn, based on OSL datings, chronologic interpretation of heavy metal profiles, and the historical maps. These isochrones are used to calculate the thickness of the sand bars, the residual channel fills

  17. Lung dynamics of aerosol particles with special reference to deposition model

    International Nuclear Information System (INIS)

    Takahashi, Kanji

    1977-01-01

    A movement of aerosol particles in the lungs, which was inhaled into the respiratory organ was given an outline by means of technological deposition model. The respiratory organ was considered to be one airway system, and was divided into nasopharyngeal part, trachea-bronchial part, and pulmonary part. The transport of particles in the respiratory tract was explained by mentioning structual model of the airway system, standard respiratory flow, and distribution of flow speed in the respiratory tract. It was explained that particle deposition in the respiratory tract seemed to be caused by inertia impact at bifurcation, gravity deposition and scattering deposition at tubular wall, interruption effect in nasopharyngeal part, and scattering phoresis effect in the upper respiratory tract or gas exchange part. Furthermore, an outline of calculation of the deposition amount of particles was described from a standpoint of the above-mentioned structure, breathing air flow, and deposition structure of particles. (Kanao, N.)

  18. Control volume based modelling of compressible flow in reciprocating machines

    DEFF Research Database (Denmark)

    Andersen, Stig Kildegård; Thomsen, Per Grove; Carlsen, Henrik

    2004-01-01

    , and multidimensional effects must be calculated using empirical correlations; correlations for steady state flow can be used as an approximation. A transformation that assumes ideal gas is presented for transforming equations for masses and energies in control volumes into the corresponding pressures and temperatures......An approach to modelling unsteady compressible flow that is primarily one dimensional is presented. The approach was developed for creating distributed models of machines with reciprocating pistons but it is not limited to this application. The approach is based on the integral form of the unsteady...... conservation laws for mass, energy, and momentum applied to a staggered mesh consisting of two overlapping strings of control volumes. Loss mechanisms can be included directly in the governing equations of models by including them as terms in the conservation laws. Heat transfer, flow friction...

  19. 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.

  20. Modeling the energy deposition in the Aurora KrF laser amplifier chain

    International Nuclear Information System (INIS)

    Comly, J.C.; Czuchlewski, S.J.; Greene, D.P.; Hanson, D.E.; Krohn, B.J.; McCown, A.W.

    1988-01-01

    Monte Carlo calculations model the energy depositions by highly energetic electron beams into the cavities of the four KrF laser amplifiers in the Aurora chain. Deposited energy density distributions are presented and studied as functions of e-beam energy and gas pressure. Results are useful for analyzing small signal gain (SSG) measurements and optimizing deposition in future experiments. 7 refs., 7 figs., 1 tab

  1. 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

  2. 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.

  3. Carbonatites of the World, Explored Deposits of Nb and REE - Database and Grade and Tonnage Models

    Science.gov (United States)

    Berger, Vladimir I.; Singer, Donald A.; Orris, Greta J.

    2009-01-01

    This report is based on published tonnage and grade data on 58 Nb- and rare-earth-element (REE)-bearing carbonatite deposits that are mostly well explored and are partially mined or contain resources of these elements. The deposits represent only a part of the known 527 carbonatites around the world, but they are characterized by reliable quantitative data on ore tonnages and grades of niobium and REE. Grade and tonnage models are an important component of mineral resource assessments. Carbonatites present one of the main natural sources of niobium and rare-earth elements, the economic importance of which grows consistently. A purpose of this report is to update earlier publications. New information about known deposits, as well as data on new deposits published during the last decade, are incorporated in the present paper. The compiled database (appendix 1; linked to right) contains 60 explored Nb- and REE-bearing carbonatite deposits - resources of 55 of these deposits are taken from publications. In the present updated grade-tonnage model we have added 24 deposits comparing with the previous model of Singer (1998). Resources of most deposits are residuum ores in the upper part of carbonatite bodies. 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 are present 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 the grade and tonnage models allow economists to

  4. Pancreas Volume and Fat Deposition in Diabetes and Normal Physiology: Consideration of the Interplay Between Endocrine and Exocrine Pancreas.

    Science.gov (United States)

    Saisho, Yoshifumi

    2016-01-01

    The pancreas is comprised of exocrine and endocrine components. Despite the fact that they are derived from a common origin in utero, these two compartments are often studied individually because of the different roles and functions of the exocrine and endocrine pancreas. Recent studies have shown that not only type 1 diabetes (T1D), but also type 2 diabetes (T2D), is characterized by a deficit in beta-cell mass, suggesting that pathological changes in the pancreas are critical events in the natural history of diabetes. In both patients with T1D and those with T2D, pancreas mass and exocrine function have been reported to be reduced. On the other hand, pancreas volume and pancreatic fat increase with obesity. Increased beta-cell mass with increasing obesity has also been observed in humans, and ectopic fat deposits in the pancreas have been reported to cause beta-cell dysfunction. Moreover, neogenesis and transdifferentiation from the exocrine to the endocrine compartment in the postnatal period are regarded as a source of newly formed beta-cells. These findings suggest that there is important interplay between the endocrine and exocrine pancreas throughout life. This review summarizes the current knowledge on physiological and pathological changes in the exocrine and endocrine pancreas (i.e., beta-cell mass), and discusses the potential mechanisms of the interplay between the two compartments in humans to understand the pathophysiology of diabetes better.

  5. Pancreas Volume and Fat Deposition in Diabetes and Normal Physiology: Consideration of the Interplay Between Endocrine and Exocrine Pancreas

    Science.gov (United States)

    Saisho, Yoshifumi

    2016-01-01

    The pancreas is comprised of exocrine and endocrine components. Despite the fact that they are derived from a common origin in utero, these two compartments are often studied individually because of the different roles and functions of the exocrine and endocrine pancreas. Recent studies have shown that not only type 1 diabetes (T1D), but also type 2 diabetes (T2D), is characterized by a deficit in beta-cell mass, suggesting that pathological changes in the pancreas are critical events in the natural history of diabetes. In both patients with T1D and those with T2D, pancreas mass and exocrine function have been reported to be reduced. On the other hand, pancreas volume and pancreatic fat increase with obesity. Increased beta-cell mass with increasing obesity has also been observed in humans, and ectopic fat deposits in the pancreas have been reported to cause beta-cell dysfunction. Moreover, neogenesis and transdifferentiation from the exocrine to the endocrine compartment in the postnatal period are regarded as a source of newly formed beta-cells. These findings suggest that there is important interplay between the endocrine and exocrine pancreas throughout life. This review summarizes the current knowledge on physiological and pathological changes in the exocrine and endocrine pancreas (i.e., beta-cell mass), and discusses the potential mechanisms of the interplay between the two compartments in humans to understand the pathophysiology of diabetes better. PMID:28012279

  6. Model of modern dynamic deposition in the east China Sea

    Science.gov (United States)

    Zhou, Fugen

    1989-09-01

    Since the last rising of sea level, two branches of the Kuroshio, the Huanghai (Yellow Sea) coastal current (HCC; mainly cold water mass) and the Changjiang River outflow have controlled the modern dynamic deposition in the East China Sea. There are three depositing areas on the sea-bed under the above currents: a relict sand area un der the Taiwan Warm Current and the Huanghai Warm Current at the south-eastern area, the about 60 km2 round mud bank under the Huanghai Coastal Current at the northern area and the large subaqueous delta of mainly fine sand and silt under the Changjiang discharge flow in its estuary and the large narrow mud bank under the Zhejiang-Fujian Coastal Current, another round mud bank under the Changjiang discharge flow off Hangzhou Bay. The relict sand area has a coarsesand block under the Taiwan Warm Current bypassing Taiwan at the northern part of the island. The two round mud banks were formed in relatively static states by an anticlockwise converging cyclonic eddy. The coarsesand block was formed by a clockwise diverging cyclonic eddy. This new dynamic deposition theory can be used to explain not only the dynamic deposition process of clay, but also the patchy distribution of sediments on the shelves of the world ocean s.

  7. 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)

  8. 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

  9. 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....

  10. Model documentation: Natural Gas Transmission and Distribution Model of the National Energy Modeling System; Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-02-24

    The Natural Gas Transmission and Distribution Model (NGTDM) is a component of the National Energy Modeling System (NEMS) used to represent the domestic natural gas transmission and distribution system. NEMS is the third in a series of computer-based, midterm energy modeling systems used since 1974 by the Energy Information Administration (EIA) and its predecessor, the Federal Energy Administration, to analyze domestic energy-economy markets and develop projections. This report documents the archived version of NGTDM that was used to produce the natural gas forecasts used in support of the Annual Energy Outlook 1994, DOE/EIA-0383(94). The purpose of this report is to provide a reference document for model analysts, users, and the public that defines the objectives of the model, describes its basic design, provides detail on the methodology employed, and describes the model inputs, outputs, and key assumptions. It is intended to fulfill the legal obligation of the EIA to provide adequate documentation in support of its models (Public Law 94-385, Section 57.b.2). This report represents Volume 1 of a two-volume set. (Volume 2 will report on model performance, detailing convergence criteria and properties, results of sensitivity testing, comparison of model outputs with the literature and/or other model results, and major unresolved issues.) Subsequent chapters of this report provide: (1) an overview of the NGTDM (Chapter 2); (2) a description of the interface between the National Energy Modeling System (NEMS) and the NGTDM (Chapter 3); (3) an overview of the solution methodology of the NGTDM (Chapter 4); (4) the solution methodology for the Annual Flow Module (Chapter 5); (5) the solution methodology for the Distributor Tariff Module (Chapter 6); (6) the solution methodology for the Capacity Expansion Module (Chapter 7); (7) the solution methodology for the Pipeline Tariff Module (Chapter 8); and (8) a description of model assumptions, inputs, and outputs (Chapter 9).

  11. Metallogenesis and metallogenic model of Nuheting uranium deposit in Erlian Basin

    International Nuclear Information System (INIS)

    Li Hongjun; Kuang Wenzhan

    2010-01-01

    Based on the study on geological characteristics, metallogesis and geochemical features in Nuheting uranium deposit, it is considered that the deposit belongs to syn-sedimentary and epigenetic reworking type. The deposit position was controlled by the lake area developed during Erlian period in Late Cretaceous. The metallognesis has experienced three stages, they are syn-sedimentary metallogenesis, epigenetic reworking metallogenesis and exogenic metallogenesis. The ore-forming ages are respectively 85 Ma, (41±5)Ma and 6-13 Ma. Based on the summary of metallogenic geological features,metallogenesis and geochemical features, the metallogenic model of Nuheting uranium deposit has been established. (authors)

  12. Characteristics and model of sandstone type uranium deposit in south of Songliao basin

    International Nuclear Information System (INIS)

    Yu Wenbin; Yu Zhenqing

    2010-01-01

    Through analyzing the uranium deposit tectonic environment, upper cretaceous sequence stratigraphy, depositional system, evolutionary characteristics of sand bodies, the effect of subsequent transformation and the characteristic of uranium deposit, the sandstone type uranium deposit in southern basin is different from typical interlayer oxidation zone sandstone type uranium deposit. The formation and evolution of sandstone-type uranium deposit are controlled by structure fensters; the favorable sedimentary facies type is braided river facies, and the ore body is braided river sand body. The size of uranium deposits is controlled by the local oxidation zone with the characteristics of sandstone type uranium deposit in partial oxidation zone. Uranium ore bodies which distribute in the roof wings of structure fenstes, and occur in gray layers between the upper and lower oxidation zone, showing tabular, and the plate of uranium ore body is controlled by the local oxidation zone. Based on the geological features of sandstone-type uranium deposits, the metallogenic model of local oxidation zones sandstone-type uranium deposits has been set up in the south of Songliao Baisn. (authors)

  13. 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.

  14. Recent developments in modelling of nitrogen deposition. Realization of nature targets under pressure

    International Nuclear Information System (INIS)

    Verhees, L.; Erbrink, H.; De Wolff, J.

    2010-01-01

    The objective of Natura 2000 is to reverse the decline in biodiversity. Nitrogen deposition is one of the main problems in implementation in the Netherlands. This article explains how nitrogen deposition is calculated with computer models and how contributions from various sources including dairy farming, road traffic and industry are related to each other, paying specific attention to the large local differences. [nl

  15. MODEL PERUBAHAN VOLUME KERIPIK BUAH SELAMA PROSES PENGGORENGAN SECARA VAKUM [Model for Volume Changes in Fruit Chips during Vacuum Frying

    Directory of Open Access Journals (Sweden)

    Jamaluddin1*

    2011-06-01

    Full Text Available Expansion and puffing are specific characteristics of fried products critical for consumer preferences. To obtain expanded and puffed dried products that fit well with consumer acceptance criteria, it is necessary to pay attention to the process conditions which change the raw material characteristics during frying. The important changes include volume and density ratio of the products during frying. Hypothetically, these changes are due to water vaporization and the decrease dry matter in the products. The objective of this research is to develop a mathematical model of volume and density ratio changes for jack fruit during vacuum frying as a function of water and starch content reductions. Samples were vacuum fried at 70–100OC and pressure of 80-90 kPa for 15–60 min. The parameters observed were volume and density as well as water and starch contents of samples before and after vacuum frying. The results showed that the developed model can be used to predict changes in volume and density ratio of jack fruit during vacuum frying.

  16. 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

    is configured entirely through a graphical user interface integrated in the standard FLUENTe interface. The model considers fine and coarse mode ash deposition and sticking mechanisms for the complete deposit growth, as well as an influence on the local boundary conditions for heat transfer due to thermal...... in the reminder of the paper. The growth of deposits on furnace walls and super heater tubes is treated including the impact on heat transfer rates determined by the CFD code. Based on the commercial CFD code FLUENTe, the overall model is fully implemented through the User Defined Functions. The model...

  17. The impact of atmospheric deposition and climate on forest growth in Europe using two empirical modelling approaches

    Science.gov (United States)

    Dobbertin, M.; Solberg, S.; Laubhann, D.; Sterba, H.; Reinds, G. J.; de Vries, W.

    2009-04-01

    Most recent studies show increasing forest growth in central Europe, rather than a decline as was expected due to negative effects of air pollution. While nitrogen deposition, increasing temperature and change in forest management are discussed as possible causes, quantification of the various environmental factors has rarely been undertaken. In our study, we used data from several hundreds of intensive monitoring plots from the ICP Forests network in Europe, ranging from northern Finland to Spain and southern Italy. Five-year growth data for the period 1994-1999 were available from roughly 650 plots to examine the influence of environmental factors on forest growth. Evaluations focused on the influence of nitrogen, sulphur and acid deposition, temperature, precipitation and drought. Concerning the latter meteorological variables we used the deviation from the long-term (30 years) mean. The study included the main tree species common beech (Fagus sylvatica), sessile or pedunculate oak (Quercus petraea and Q. robur), Scots pine (Pinus sylvestris) and Norway spruce (Picea abies). Two very different approaches were used. In the first approach an individual tree-based regression model was applied (Laubhahn et al., 2009), while in the second approach a stand-based model was applied (Solberg et al., 2009). The individual tree-based model had measured basal area increment of each individual tree as a growth response variable and tree size (diameter at breast height), tree competition (basal area of larger trees and stand density index), site factors (e.g. soil C/N ratio, temperature), and environmental factors (e.g. temperature change compared to long-term average, nitrogen and sulphur deposition) as influencing parameters. In the stand-growth model, stem volume increment was used as the growth response variable, after filtering out the expected growth. Expected growth was modelled as a function of site productivity, stand age and a stand density index. Relative volume

  18. 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.

  19. Modeling of atomic layer deposition on nanoparticle agglomerates

    NARCIS (Netherlands)

    Jin, W.

    2017-01-01

    Nanoparticles are increasingly applied in a range of fields, such as electronics, catalysis, energy and medicine, due to their small sizes and consequent high surface-volume ratio. In many applications, it is attractive to coat the nanoparticles with a layer of different materials in order to gain

  20. A Computational Model of Hydraulic Volume Displacement Drive

    Directory of Open Access Journals (Sweden)

    V. N. Pil'gunov

    2014-01-01

    Full Text Available The paper offers a computational model of industrial-purpose hydraulic drive with two hydraulic volume adjustable working chamber machines (pump and motor. Adjustable pump equipped with the pressure control unit can be run together with several adjustable hydraulic motors on the principle of three-phase hydraulic socket-outlet with high-pressure lines, drain, and drainage system. The paper considers the pressure-controlled hydrostatic transmission with hydraulic motor as an output link. It shows a possibility to create a saving hydraulic drive using a functional tie between the adjusting parameters of the pump and hydraulic motor through the pressure difference, torque, and angular rate of the hydraulic motor shaft rotation. The programmable logic controller can implement such tie. The Coulomb and viscous frictions are taken into consideration when developing a computational model of the hydraulic volume displacement drive. Discharge balance considers external and internal leakages in equivalent clearances of hydraulic machines, as well as compression loss volume caused by hydraulic fluid compressibility and deformation of pipe walls. To correct dynamic properties of hydraulic drive, the paper offers that in discharge balance are included the additional regulated external leakages in the open circuit of hydraulic drive and regulated internal leakages in the closed-loop circuit. Generalized differential equations having functional multipliers and multilinked nature have been obtained to describe the operation of hydraulic positioning and speed drive with two hydraulic volume adjustable working chamber machines. It is shown that a proposed computational model of hydraulic drive can be taken into consideration in development of LS («Load-Sensing» drives, in which the pumping pressure is tuned to the value required for the most loaded slave motor to overcome the load. Results attained can be used both in designing the industrial-purpose heavy

  1. 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)

  2. Modelling and Simulation of Volume Controlled Mechanical Ventilation System

    Directory of Open Access Journals (Sweden)

    Yan Shi

    2014-01-01

    Full Text Available Volume controlled mechanical ventilation system is a typical time-delay system, which is applied to ventilate patients who cannot breathe adequately on their own. To illustrate the influences of key parameters of the ventilator on the dynamics of the ventilated respiratory system, this paper firstly derived a new mathematical model of the ventilation system; secondly, simulation and experimental results are compared to verify the mathematical model; lastly, the influences of key parameters of ventilator on the dynamics of the ventilated respiratory system are carried out. This study can be helpful in the VCV ventilation treatment and respiratory diagnostics.

  3. Development of modelling and forecasting in geology. (Volume 2)

    International Nuclear Information System (INIS)

    Seguin, J.J.; Fourniguet, J.; Peaudecerf, P.

    1990-01-01

    To access the long-term safety of radioactive waste disposal systems, validation of predictive models is essential and large efforts should be given to barriers, particularly geologic barriers. This work appears in the form of four volumes, the subject of the second part is described below. HERODE (calculation of relief altitude under erosion process from 0 to 100000 years) is a weathering and erosion computerized simulation. The model describes materials and rocks transport and also substratum weathering process. FORTRAN 77 is the software language. 31 figs., 6 tabs., 40 refs

  4. Particle deposition modeling in the secondary side of a steam generator bundle model

    Energy Technology Data Exchange (ETDEWEB)

    Mukin, Roman, E-mail: roman.mukin@psi.ch; Dehbi, Abdel, E-mail: abdel.dehbi@psi.ch

    2016-04-01

    A steam generator (SG) tube rupture (SGTR) model is studied in this paper. This model based on a experimental facility called Aerosol Trapping In a Steam Generator (ARTIST), which is a model of a scaled steam generator tube bundle consisting of 270 tubes and a guillotine tube to address aerosol deposition phenomena on two different scales: near the tube break, where the gas velocities and turbulence are very intensive, and far away from the break, where the flow velocities are three orders of magnitude lower. Owing to complexity of the flow, 3D simulations with highly resolved computational mesh near the break were done. First, the flow inside an isolated tube with a guillotine tube break has been studied in the framework of Reynolds Averaged Navier Stokes (RANS) approach. The next part is devoted to the simulation of an inclined gas jet entering the SG tube bundle via the guillotine tube breach with more advanced CFD tools. In particular, Detached Eddy Simulation (DES) and RANS are applied to tackle the wide range of flow scales. Flow field velocity comparison showed that DES results are reproducing wavy structure of the flow field in far field from the break observed in experiment. Particle transport and deposition is modelled by Lagrangian continuous random walk (CRW) model, which has been developed and validated previously. It is found that the DES combined with the CRW to supply fluctuating velocity components predicts deposition rates that are generally within the scatter of the measured data. Monodisperse, spherical SiO{sub 2} particles with AMMD = 1.4 μm were used as aerosol particles in simulations. To be economically feasible, the computations were made with the open source CFD code OpenFOAM. Comparison of the calculated flow with the experimental axial velocity distribution data at different vertical levels has been performed.

  5. Alkali deposits found in biomass boilers: The behavior of inorganic material in biomass-fired power boilers -- Field and laboratory experiences. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, L.L. [Sandia National Labs., Livermore, CA (United States). Combustion Research Facility; Miles, T.R.; Miles, T.R. Jr. [Miles (Thomas R.), Portland, OR (United States); Jenkins, B.M. [California Univ., Davis, CA (United States); Dayton, D.C.; Milne, T.A. [National Renewable Energy Lab., Golden, CO (United States); Bryers, R.W. [Foster Wheeler Development Corp., Livingston, NJ (United States); Oden, L.L. [Bureau of Mines, Albany, OR (United States). Albany Research Center

    1996-03-01

    This report documents the major findings of the Alkali Deposits Investigation, a collaborative effort to understand the causes of unmanageable ash deposits in biomass-fired electric power boilers. Volume 1 of this report provide an overview of the project, with selected highlights. This volume provides more detail and discussion of the data and implications. This document includes six sections. The first, the introduction, provides the motivation, context, and focus for the investigation. The remaining sections discuss fuel properties, bench-scale combustion tests, a framework for considering ash deposition processes, pilot-scale tests of biomass fuels, and field tests in commercially operating biomass power generation stations. Detailed chemical analyses of eleven biomass fuels representing a broad cross-section of commercially available fuels reveal their properties that relate to ash deposition tendencies. The fuels fall into three broad categories: (1) straws and grasses (herbaceous materials); (2) pits, shells, hulls and other agricultural byproducts of a generally ligneous nature; and (3) woods and waste fuels of commercial interest. This report presents a systematic and reasonably detailed analysis of fuel property, operating condition, and boiler design issues that dictate ash deposit formation and property development. The span of investigations from bench-top experiments to commercial operation and observations including both practical illustrations and theoretical background provide a self-consistent and reasonably robust basis to understand the qualitative nature of ash deposit formation in biomass boilers. While there remain many quantitative details to be pursued, this project encapsulates essentially all of the conceptual aspects of the issue. It provides a basis for understanding and potentially resolving the technical and environmental issues associated with ash deposition during biomass combustion. 81 refs., 124 figs., 76 tabs.

  6. 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

  7. Puff-plume atmospheric deposition model for use at SRP in emergency-response situations

    International Nuclear Information System (INIS)

    Garrett, A.J.; Murphy, C.E. Jr.

    1981-05-01

    An atmospheric transport and diffusion model developed for real-time calculation of the location and concentration of toxic or radioactive materials during an accidental release was improved by including deposition calculations

  8. Assessment of a numerical model to reproduce event‐scale erosion and deposition distributions in a braided river

    Science.gov (United States)

    Measures, R.; Hicks, D. M.; Brasington, J.

    2016-01-01

    Abstract Numerical morphological modeling of braided rivers, using a physics‐based approach, is increasingly used as a technique to explore controls on river pattern and, from an applied perspective, to simulate the impact of channel modifications. This paper assesses a depth‐averaged nonuniform sediment model (Delft3D) to predict the morphodynamics of a 2.5 km long reach of the braided Rees River, New Zealand, during a single high‐flow event. Evaluation of model performance primarily focused upon using high‐resolution Digital Elevation Models (DEMs) of Difference, derived from a fusion of terrestrial laser scanning and optical empirical bathymetric mapping, to compare observed and predicted patterns of erosion and deposition and reach‐scale sediment budgets. For the calibrated model, this was supplemented with planform metrics (e.g., braiding intensity). Extensive sensitivity analysis of model functions and parameters was executed, including consideration of numerical scheme for bed load component calculations, hydraulics, bed composition, bed load transport and bed slope effects, bank erosion, and frequency of calculations. Total predicted volumes of erosion and deposition corresponded well to those observed. The difference between predicted and observed volumes of erosion was less than the factor of two that characterizes the accuracy of the Gaeuman et al. bed load transport formula. Grain size distributions were best represented using two φ intervals. For unsteady flows, results were sensitive to the morphological time scale factor. The approach of comparing observed and predicted morphological sediment budgets shows the value of using natural experiment data sets for model testing. Sensitivity results are transferable to guide Delft3D applications to other rivers. PMID:27708477

  9. Assessment of a numerical model to reproduce event-scale erosion and deposition distributions in a braided river.

    Science.gov (United States)

    Williams, R D; Measures, R; Hicks, D M; Brasington, J

    2016-08-01

    Numerical morphological modeling of braided rivers, using a physics-based approach, is increasingly used as a technique to explore controls on river pattern and, from an applied perspective, to simulate the impact of channel modifications. This paper assesses a depth-averaged nonuniform sediment model (Delft3D) to predict the morphodynamics of a 2.5 km long reach of the braided Rees River, New Zealand, during a single high-flow event. Evaluation of model performance primarily focused upon using high-resolution Digital Elevation Models (DEMs) of Difference, derived from a fusion of terrestrial laser scanning and optical empirical bathymetric mapping, to compare observed and predicted patterns of erosion and deposition and reach-scale sediment budgets. For the calibrated model, this was supplemented with planform metrics (e.g., braiding intensity). Extensive sensitivity analysis of model functions and parameters was executed, including consideration of numerical scheme for bed load component calculations, hydraulics, bed composition, bed load transport and bed slope effects, bank erosion, and frequency of calculations. Total predicted volumes of erosion and deposition corresponded well to those observed. The difference between predicted and observed volumes of erosion was less than the factor of two that characterizes the accuracy of the Gaeuman et al. bed load transport formula. Grain size distributions were best represented using two φ intervals. For unsteady flows, results were sensitive to the morphological time scale factor. The approach of comparing observed and predicted morphological sediment budgets shows the value of using natural experiment data sets for model testing. Sensitivity results are transferable to guide Delft3D applications to other rivers.

  10. 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

  11. 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

  12. Modeling of Cementitious Representative Volume Element with Additives

    Science.gov (United States)

    Shahzamanian, M. M.; Basirun, W. J.

    CEMHYD3D has been employed to simulate the representative volume element (RVE) of cementitious systems (Type I cement) containing fly ash (Class F) through a voxel-based finite element analysis (FEA) approach. Three-dimensional microstructures composed of voxels are generated for a heterogeneous cementitious material consisting of various constituent phases. The primary focus is to simulate a cementitious RVE containing fly ash and to present the homogenized macromechanical properties obtained from its analysis. Simple kinematic uniform boundary conditions as well as periodic boundary conditions were imposed on the RVE to obtain the principal and shear moduli. Our current work considers the effect of fly ash percentage on the elastic properties based on the mass and volume replacements. RVEs with lengths of 50, 100 and 200μm at different degrees of hydration are generated, and the elastic properties are modeled and simulated. In general, the elastic properties of a cementitious RVE with fly ash replacement for cement based on mass and volume differ from each other. Moreover, the finite element (FE) mesh density effect is studied. Results indicate that mechanical properties decrease with increasing mesh density.

  13. 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.

  14. Development of a Zealand White Rabbit Deposition Model to Study Inhalation Anthrax

    Science.gov (United States)

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

    2016-01-01

    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. PMID:26895308

  15. 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

    All sediment-hosted gold deposits (as a single population) share one characteristic—they all have disseminated micron-sized invisible gold in sedimentary rocks. Sediment-hosted gold deposits are recognized in the Great Basin province of the western United States and in China along with a few recognized deposits in Indonesia, Iran, and Malaysia. Three new grade and tonnage models for sediment-hosted gold deposits are presented in this paper: (1) a general sediment-hosted gold type model, (2) a Carlin subtype model, and (3) a Chinese subtype model. These models are based on grade and tonnage data from a database compilation of 118 sediment-hosted gold deposits including a total of 123 global deposits. The new general grade and tonnage model for sediment-hosted gold deposits (n=118) has a median tonnage of 5.7 million metric tonnes (Mt) and a gold grade of 2.9 grams per tonne (g/t). This new grade and tonnage model is remarkable in that the estimated parameters of the resulting grade and tonnage distributions are comparable to the previous model of Mosier and others (1992). A notable change is in the reporting of silver in more than 10 percent of deposits; moreover, the previous model had not considered deposits in China. From this general grade and tonnage model, two significantly different subtypes of sediment-hosted gold deposits are differentiated: Carlin and Chinese. The Carlin subtype includes 88 deposits in the western United States, Indonesia, Iran, and Malaysia, with median tonnage and grade of 7.1 Mt and 2.0 g/t Au, respectively. The silver grade is 0.78 g/t Ag for the 10th percentile of deposits. The Chinese subtype represents 30 deposits in China, with a median tonnage of 3.9 Mt and medium grade of 4.6 g/t Au. Important differences are recognized in the mineralogy and alteration of the two sediment-hosted gold subtypes such as: increased sulfide minerals in the Chinese subtype and decalcification alteration dominant in the Carlin type. We therefore

  16. Energy deposition patterns within limb models heated with a mini annular phased array (MAPA) applicator

    International Nuclear Information System (INIS)

    Guerquin-Kern, J.L.; Hagmann, M.J.; Charny, C.K.; Levin, R.L.

    1986-01-01

    A series of experiments has been carried out in order to characterize a MAPA applicator prior to possible clinical implementation. The energy deposition patterns were determined in several human limb models of different complexities. The maximum energy deposition observed in a homogeneous cylindrical phantom was found to be at the middle of the applicator. For more realistically shaped, homogeneous limb models, the point of maximum energy deposition was shifted towards a smaller cross-sectional region; this was also the case for isolated human legs. Furthermore, significant heating was observed in the bone of the isolated legs. Such phenomena illustrate the limitation of using classical 2-D numerical models for predicting the energy deposition patterns in heterogeneous bodies

  17. High performance W-AIN cermet solar coatings designed by modelling calculations and deposited by DC magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Qi-Chu Zhang [The University of Sydney (Australia). School of Physics; Shen, Y.G. [City University of Hong Kong (Hong Kong). Department of Manufacturing Engineering and Engineering Management

    2004-01-25

    High solar performance W-AIN cermet solar coatings were designed using a numerical computer model and deposited experimentally. In the numerical calculations aluminium oxynitride (AlON) was used as ceramic component. The dielectric functions and then complex refractive index of W-AlON cermet materials were calculated using the Sheng's approximation. The layer thickness and W metal volume fraction were optimised to achieve maximum photo-thermal conversion efficiency for W-AlON cermet solar coatings on an Al reflector with a surface AlON ceramic anti-reflection layer. Optimisation calculations show that the W-AlON cermet solar coatings with two and three cermet layers have nearly identical solar absorptance, emittance and photo-thermal conversion efficiency that are much better than those for films with one cermet layer. The optimised calculated AlON/W-AlON/Al solar coating film with two cermet layers has a high solar absorptance of 0.953 and a low hemispherical emittance of 0.051 at 80{sup o}C for a concentration factor of 2. The AlN/W-AlN/Al solar selective coatings with two cermet layers were deposited using two metal target direct current magnetron sputtering technology. During the deposition of W-AlN cermet layer, both Al and W targets were run simultaneously in a gas mixture of argon and nitrogen. By substrate rotation a multi-sub-layer system consisting of alternating AlN ceramic and W metallic sub-layers was deposited that can be considered as a macro-homogeneous W-AlN cermet layer. A solar absorptance of 0.955 and nearly normal emittance of 0.056 at 80{sup o}C have been achieved for deposited W-AlN cermet solar coatings. (author)

  18. High performance W-AlN cermet solar coatings designed by modelling calculations and deposited by DC magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Qi-Chu [School of Physics, The University of Sydney, Sydney, NSW 2006 (Australia); Shen, Y.G. [Department of Manufacturing Engineering and Engineering Management, City University of Hong Kong (Hong Kong)

    2004-01-25

    High solar performance W-AlN cermet solar coatings were designed using a numerical computer model and deposited experimentally. In the numerical calculations aluminium oxynitride (AlON) was used as ceramic component. The dielectric function and then complex refractive index of W-AlON cermet materials were calculated using the Sheng's approximation. The layer thickness and W metal volume fraction were optimised to achieve maximum photo-thermal conversion efficiency for W-AlON cermet solar coatings on an Al reflector with a surface AlON ceramic anti-reflection layer. Optimisation calculations show that the W-AlON cermet solar coatings with two and three cermet layers have nearly identical solar absorptance, emittance and photo-thermal conversion efficiency that are much better than those for films with one cermet layer. The optimised calculated AlON/W-AlON/Al solar coating film with two cermet layers has a high solar absorptance of 0.953 and a low hemispherical emittance of 0.051 at 80C for a concentration factor of 2. The AlN/W-AlN/Al solar selective coatings with two cermet layers were deposited using two metal target direct current magnetron sputtering technology. During the deposition of W-AlN cermet layer, both Al and W targets were run simultaneously in a gas mixture of argon and nitrogen. By substrate rotation a multi-sub-layer system consisting of alternating AlN ceramic and W metallic sub-layers was deposited that can be considered as a macro-homogeneous W-AlN cermet layer. A solar absorptance of 0.955 and nearly normal emittance of 0.056 at 80C have been achieved for deposited W-AlN cermet solar coatings.

  19. Volume Dynamics Propulsion System Modeling for Supersonics Vehicle Research

    Science.gov (United States)

    Kopasakis, George; Connolly, Joseph W.; Paxson, Daniel E.; Ma, Peter

    2010-01-01

    Under the NASA Fundamental Aeronautics Program the Supersonics Project is working to overcome the obstacles to supersonic commercial flight. The proposed vehicles are long slim body aircraft with pronounced aero-servo-elastic modes. These modes can potentially couple with propulsion system dynamics; leading to performance challenges such as aircraft ride quality and stability. Other disturbances upstream of the engine generated from atmospheric wind gusts, angle of attack, and yaw can have similar effects. In addition, for optimal propulsion system performance, normal inlet-engine operations are required to be closer to compressor stall and inlet unstart. To study these phenomena an integrated model is needed that includes both airframe structural dynamics as well as the propulsion system dynamics. This paper covers the propulsion system component volume dynamics modeling of a turbojet engine that will be used for an integrated vehicle Aero-Propulso-Servo-Elastic model and for propulsion efficiency studies.

  20. Finite volume model for two-dimensional shallow environmental flow

    Science.gov (United States)

    Simoes, F.J.M.

    2011-01-01

    This paper presents the development of a two-dimensional, depth integrated, unsteady, free-surface model based on the shallow water equations. The development was motivated by the desire of balancing computational efficiency and accuracy by selective and conjunctive use of different numerical techniques. The base framework of the discrete model uses Godunov methods on unstructured triangular grids, but the solution technique emphasizes the use of a high-resolution Riemann solver where needed, switching to a simpler and computationally more efficient upwind finite volume technique in the smooth regions of the flow. Explicit time marching is accomplished with strong stability preserving Runge-Kutta methods, with additional acceleration techniques for steady-state computations. A simplified mass-preserving algorithm is used to deal with wet/dry fronts. Application of the model is made to several benchmark cases that show the interplay of the diverse solution techniques.

  1. 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

  2. Modeling the global atmospheric transport and deposition of mercury to the Great Lakes

    Directory of Open Access Journals (Sweden)

    Mark D. Cohen

    2016-07-01

    Full Text Available Abstract Mercury contamination in the Great Lakes continues to have important public health and wildlife ecotoxicology impacts, and atmospheric deposition is a significant ongoing loading pathway. The objective of this study was to estimate the amount and source-attribution for atmospheric mercury deposition to each lake, information needed to prioritize amelioration efforts. A new global, Eulerian version of the HYSPLIT-Hg model was used to simulate the 2005 global atmospheric transport and deposition of mercury to the Great Lakes. In addition to the base case, 10 alternative model configurations were used to examine sensitivity to uncertainties in atmospheric mercury chemistry and surface exchange. A novel atmospheric lifetime analysis was used to characterize fate and transport processes within the model. Model-estimated wet deposition and atmospheric concentrations of gaseous elemental mercury (Hg(0 were generally within ∼10% of measurements in the Great Lakes region. The model overestimated non-Hg(0 concentrations by a factor of 2–3, similar to other modeling studies. Potential reasons for this disagreement include model inaccuracies, differences in atmospheric Hg fractions being compared, and the measurements being biased low. Lake Erie, downwind of significant local/regional emissions sources, was estimated by the model to be the most impacted by direct anthropogenic emissions (58% of the base case total deposition, while Lake Superior, with the fewest upwind local/regional sources, was the least impacted (27%. The U.S. was the largest national contributor, followed by China, contributing 25% and 6%, respectively, on average, for the Great Lakes. The contribution of U.S. direct anthropogenic emissions to total mercury deposition varied between 46% for the base case (with a range of 24–51% over all model configurations for Lake Erie and 11% (range 6–13% for Lake Superior. These results illustrate the importance of atmospheric

  3. 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

  4. Hydromechanical modelling with application in sealing for underground waste deposition

    Energy Technology Data Exchange (ETDEWEB)

    Hasal, Martin, E-mail: martin.hasal@vsb.cz; Michalec, Zdeněk; Blaheta, Radim [Institute of Geonics AS CR, Studentska 1768, 70800 Ostrava-Poruba (Czech Republic)

    2015-03-10

    Hydro-mechanical models appear in simulation of many environmental problems related to construction of engineering barriers for contaminant spreading. The presented work aims in modelling bentonite-sand barriers, which can be used for nuclear waste isolation and similar problems. Particularly, we use hydro-mechanical model coupling unsaturated flow and (nonlinear) elasticity, implement such model in COMSOL software and show application in simulation of an infiltration test (2D axisymmetric model) and the SEALEX Water test WT1 experiment (3D model). Finally, we discuss the needs and possibilities of parallel high performance computing.

  5. 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)

  6. 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

  7. Sources and processes contributing to nitrogen deposition: an adjoint model analysis applied to biodiversity hotspots worldwide.

    Science.gov (United States)

    Paulot, Fabien; Jacob, Daniel J; Henze, Daven K

    2013-04-02

    Anthropogenic enrichment of reactive nitrogen (Nr) deposition is an ecological concern. We use the adjoint of a global 3-D chemical transport model (GEOS-Chem) to identify the sources and processes that control Nr deposition to an ensemble of biodiversity hotspots worldwide and two U.S. national parks (Cuyahoga and Rocky Mountain). We find that anthropogenic sources dominate deposition at all continental sites and are mainly regional (less than 1000 km) in origin. In Hawaii, Nr supply is controlled by oceanic emissions of ammonia (50%) and anthropogenic sources (50%), with important contributions from Asia and North America. Nr deposition is also sensitive in complicated ways to emissions of SO2, which affect Nr gas-aerosol partitioning, and of volatile organic compounds (VOCs), which affect oxidant concentrations and produce organic nitrate reservoirs. For example, VOC emissions generally inhibit deposition of locally emitted NOx but significantly increase Nr deposition downwind. However, in polluted boreal regions, anthropogenic VOC emissions can promote Nr deposition in winter. Uncertainties in chemical rate constants for OH + NO2 and NO2 hydrolysis also complicate the determination of source-receptor relationships for polluted sites in winter. Application of our adjoint sensitivities to the representative concentration pathways (RCPs) scenarios for 2010-2050 indicates that future decreases in Nr deposition due to NOx emission controls will be offset by concurrent increases in ammonia emissions from agriculture.

  8. A theoretical model for prediction of deposition efficiency in cold spraying

    International Nuclear Information System (INIS)

    Li Changjiu; Li Wenya; Wang Yuyue; Yang Guanjun; Fukanuma, H.

    2005-01-01

    The deposition behavior of a spray particle stream with a particle size distribution was theoretically examined for cold spraying in terms of deposition efficiency as a function of particle parameters and spray angle. The theoretical relation was established between the deposition efficiency and spray angle. The experiments were conducted by measuring deposition efficiency at different driving gas conditions and different spray angles using gas-atomized copper powder. It was found that the theoretically estimated results agreed reasonably well with the experimental ones. Based on the theoretical model and experimental results, it was revealed that the distribution of particle velocity resulting from particle size distribution influences significantly the deposition efficiency in cold spraying. It was necessary for the majority of particles to achieve a velocity higher than the critical velocity in order to improve the deposition efficiency. The normal component of particle velocity contributed to the deposition of the particle under the off-nomal spray condition. The deposition efficiency of sprayed particles decreased owing to the decrease of the normal velocity component as spray was performed at off-normal angle

  9. Application of Physiographic Soil Erosion–Deposition Model in ...

    Indian Academy of Sciences (India)

    69

    8 estimate the efficiency of empty flushing. The model was verified using data ... concern, as evidenced by the large number of reservoir sedimentation management .... the PSED model with the sediment flushing of the empty storage operation ...

  10. 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

  11. Modelling the impact of climate change and atmospheric N deposition on French forests biodiversity

    International Nuclear Information System (INIS)

    Rizzetto, Simon; Belyazid, Salim; Gégout, Jean-Claude; Nicolas, Manuel; Alard, Didier; Corcket, Emmanuel; Gaudio, Noémie; Sverdrup, Harald; Probst, Anne

    2016-01-01

    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. - Highlights: • The effects of N atmospheric deposition and climate change on vegetation were simulated. • The model ForSAFE-Veg was calibrated and validated carefully for three forests in France. • Climate has a greater influence on vegetation than N deposition in conifer forests. • N-poor ecosystems are, however, more sensitive to N deposition than to climate change. - Compared to nitrogen atmospheric deposition, climate appears to be the main driver of change in forest plant biodiversity on a century scale, except in N-poor ecosystems.

  12. 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.

  13. Deposition behaviour of model biofuel ash in mixtures with quartz sand. Part 1: Experimental data

    Energy Technology Data Exchange (ETDEWEB)

    Mischa Theis; Christian Mueller; Bengt-Johan Skrifvars; Mikko Hupa; Honghi Tran [Aabo Akademi Process Chemistry Centre, Aabo (Finland). Combustion and Materials Chemistry

    2006-10-15

    Model biofuel ash of well-defined size and melting properties was fed into an entrained flow reactor (EFR) to simulate the deposition behaviour of commercially applied biofuel mixtures in large-scale boilers. The aim was to obtain consistent experimental data that can be used for validation of computational fluid dynamics (CFD)-based deposition models. The results showed that while up to 80 wt% of the feed was lost to the EFR wall, the composition of the model ash particles collected at the reactor exit did not change. When model ashes were fed into the reactor individually, the ash particles were found to be sticky when they contained more than 15 wt% molten phase. When model ashes were fed in mixtures with silica sand, it was found that only a small amount of sand particles was captured in the deposits; the majority rebounded upon impact. The presence of sand in the feed mixture reduced the deposit buildup by more than could be expected from linear interpolation between the model ash and the sand. The results suggested that sand addition to model ash may prevent deposit buildup through erosion. 22 refs., 6 figs., 3 tabs.

  14. Effect of spray angle and spray volume on deposition of a medium droplet spray with air support in ivy pot plants.

    Science.gov (United States)

    Foqué, Dieter; Pieters, Jan G; Nuyttens, David

    2014-03-01

    Spray boom systems, an alternative to the predominantly-used spray guns, have the potential to considerably improve crop protection management in glasshouses. Based on earlier experiments, the further optimization of the deposits of a medium spray quality extended range flat fan nozzle type using easy adjustable spray boom settings was examined. Using mineral chelate tracers and water sensitive papers, the spray results were monitored at three plant levels, on the upper side and the underside of the leaves, and on some off-target collectors. In addition, the deposition datasets of all tree experiments were compared. The data showed that the most efficient spray distribution with the medium spray quality flat fan nozzles was found with a 30° forward angled spray combined with air support and an application rate of 1000 L ha(-1) . This technique resulted in a more uniform deposition in the dense canopy and increased spray deposition on the lower side of the leaves compared with the a standard spray boom application. Applying 1000 L ha(-1) in two subsequent runs instead of one did not seem to show any added value. Spray deposition can be improved hugely simply by changing some spray boom settings like nozzle type, angling the spray, using air support and adjusting the spray volume to the crop. © 2013 Society of Chemical Industry.

  15. 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.

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

    DEFF Research Database (Denmark)

    Yuan, Hao; Shapiro, Alexander

    2011-01-01

    A mathematical model for suspension/colloid flow in porous media and non-monotonic deposition is proposed. It accounts for the migration of particles associated with the pore walls via the second energy minimum (surface associated phase). The surface associated phase migration is characterized...... 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....... 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...

  17. Fixed site neutralization model programmer's manual. Volume 1

    International Nuclear Information System (INIS)

    Engi, D.; Chapman, L.; Judnick, W.; Blum, R.; Broegler, L.; Lenz, J.; Weinthraub, A.; Ballard, D.

    1979-12-01

    The Fixed Site Neutralization Model (FSNM) is a stochastic, time-stepped simulation of an engagement process whereby an adversary force attempts to steal or sabotage sensitive (e.g., nuclear) materials being guarded by a security force on a fixed site and a response force that is off-site. FSNM will assist regulatory bodies of the US Government in evaluating fixed site physical protection systems at various installations in a variety of scenarios. Most data input to the Fixed Site Neutralization Model are in binary form. The user's data are transformed into binary form by two supporting modules, the Data Preprocessor (DPP) and the Plex Preprocessor (PPP). Both preprocessors and the FSNM itself are written in FORTRAN. This volume of the program maintenance program contains: introduction, logic descriptions, PLEX data structure, PLEX records, dictionaries, and error conditions and comments

  18. Development of modelling and forecasting in geology (Volume 4)

    International Nuclear Information System (INIS)

    Courbouleix, S.; Colleau, A.; Defaut, B.; Fourniguet, J.; Peaudecerf, P.

    1990-01-01

    To access the long-term safety of radioactive waste disposal systems, validation of predictive models is essential and large efforts should be given to barriers, particularly geologic barriers. This work appears in the form of four volumes, the subject of the fourth part is described below. The purpose of this study is to find actual climates which can represent past climates in Europe, during Plio-Quaternary Palynology technics is the most adapted to restore ancient climates. A climatic index, Q n is defined as a function of yearly rainfalls, monthly extreme temperatures and aridity. A climatic diagram is built with climatic index Q n along X axis and a function of the yearly mean temperature along Y axis. This original method can ensure vegetation determination from climate and vice versa. Erosion and Weathering values may be determined after model calibration. 23 figs., 21 refs

  19. Estimating dual deposit insurance premium rates and forecasting non-performing loans: Two new models

    OpenAIRE

    Yoshino, Naoyuki; Taghizadeh-Hesary, Farhad; Nili, Farhad

    2015-01-01

    Risky banks that endanger the stability of the financial system should pay higher deposit insurance premiums than healthy banks and other financial institutions that have shown good financial performance. It is necessary, therefore, to have at least a dual fair premium rate system. In this paper, we develop a model for calculating dual fair premium rates. Our definition of a fair premium rate in this paper is a rate that could cover the operational expenditures of the deposit insuring organiz...

  20. 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)

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

    Science.gov (United States)

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

    2016-04-01

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

  2. 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.)

  3. Modeling of the Effect of Path Planning on Thermokinetic Evolutions in Laser Powder Deposition Process

    Science.gov (United States)

    Foroozmehr, Ehsan; Kovacevic, Radovan

    2011-07-01

    A thermokinetic model coupling finite-element heat transfer with transformation kinetics is developed to determine the effect of deposition patterns on the phase-transformation kinetics of laser powder deposition (LPD) process of a hot-work tool steel. The finite-element model is used to define the temperature history of the process used in an empirical-based kinetic model to analyze the tempering effect of the heating and cooling cycles of the deposition process. An area is defined to be covered by AISI H13 on a substrate of AISI 1018 with three different deposition patterns: one section, two section, and three section. The two-section pattern divides the area of the one-section pattern into two sections, and the three-section pattern divides that area into three sections. The results show that dividing the area under deposition into smaller areas can influence the phase transformation kinetics of the process and, consequently, change the final hardness of the deposited material. The two-section pattern shows a higher average hardness than the one-section pattern, and the three-section pattern shows a fully hardened surface without significant tempered zones of low hardness. To verify the results, a microhardness test and scanning electron microscope were used.

  4. Theoretical modeling of fine-particle deposition in 3-dimensional bronchial bifurcations

    International Nuclear Information System (INIS)

    Shaw, D.T.; Rajendran, N.; Liao, N.S.

    1978-01-01

    A theoretical model is developed for the prediction of the peak to average particle deposition flux in the human bronchial airways. The model involves the determination of the peak flux by a round-nose 2-dimensional bifurcation channel and the average deposition flux by a curved-tube model. The ''hot-spot'' effect for all generations in the human respiratory system is estimated. Hot spots are usually associated with the sites of bronchoconstriction or even chronic bronchitis and lung cancer. Recent studies indicate that lung cancer in smokers may be caused by the deposition of radioactive particles produced by the burning of tobacco leaves. High local concentrations of Po-210 have been measured in epithelium from bronchial bifurcations of smokes. This Po-210 is the radioactive daughter of Pb-210 which is produced from a long chain of radioactive decay starting from uranium in the fertilizer-enriched soil. It is found that the peak deposition flux is higher than the average deposition flux by a factor ranging between 5 and 30, depending on the generation number. The importance of this peak to average deposition flux ratio on consideration of environmental safety studies is discussed

  5. 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

  6. 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.

  7. 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

    2018-05-01

    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.

  8. Comparison of Statistically Modeled Contaminated Soil Volume Estimates and Actual Excavation Volumes at the Maywood FUSRAP Site - 13555

    Energy Technology Data Exchange (ETDEWEB)

    Moore, James [U.S. Army Corps of Engineers - New York District 26 Federal Plaza, New York, New York 10278 (United States); Hays, David [U.S. Army Corps of Engineers - Kansas City District 601 E. 12th Street, Kansas City, Missouri 64106 (United States); Quinn, John; Johnson, Robert; Durham, Lisa [Argonne National Laboratory, Environmental Science Division 9700 S. Cass Ave., Argonne, Illinois 60439 (United States)

    2013-07-01

    As part of the ongoing remediation process at the Maywood Formerly Utilized Sites Remedial Action Program (FUSRAP) properties, Argonne National Laboratory (Argonne) assisted the U.S. Army Corps of Engineers (USACE) New York District by providing contaminated soil volume estimates for the main site area, much of which is fully or partially remediated. As part of the volume estimation process, an initial conceptual site model (ICSM) was prepared for the entire site that captured existing information (with the exception of soil sampling results) pertinent to the possible location of surface and subsurface contamination above cleanup requirements. This ICSM was based on historical anecdotal information, aerial photographs, and the logs from several hundred soil cores that identified the depth of fill material and the depth to bedrock under the site. Specialized geostatistical software developed by Argonne was used to update the ICSM with historical sampling results and down-hole gamma survey information for hundreds of soil core locations. The updating process yielded both a best guess estimate of contamination volumes and a conservative upper bound on the volume estimate that reflected the estimate's uncertainty. Comparison of model results to actual removed soil volumes was conducted on a parcel-by-parcel basis. Where sampling data density was adequate, the actual volume matched the model's average or best guess results. Where contamination was un-characterized and unknown to the model, the actual volume exceeded the model's conservative estimate. Factors affecting volume estimation were identified to assist in planning further excavations. (authors)

  9. Hydraulic experiment on formation mechanism of tsunami deposit and verification of sediment transport model for tsunamis

    Science.gov (United States)

    Yamamoto, A.; Takahashi, T.; Harada, K.; Sakuraba, M.; Nojima, K.

    2017-12-01

    An underestimation of the 2011 Tohoku tsunami caused serious damage in coastal area. Reconsideration for tsunami estimation needs knowledge of paleo tsunamis. The historical records of giant tsunamis are limited, because they had occurred infrequently. Tsunami deposits may include many of tsunami records and are expected to analyze paleo tsunamis. However, present research on tsunami deposits are not able to estimate the tsunami source and its magnitude. Furthermore, numerical models of tsunami and its sediment transport are also important. Takahashi et al. (1999) proposed a model of movable bed condition due to tsunamis, although it has some issues. Improvement of the model needs basic data on sediment transport and deposition. This study investigated the formation mechanism of tsunami deposit by hydraulic experiment using a two-dimensional water channel with slope. In a fixed bed condition experiment, velocity, water level and suspended load concentration were measured at many points. In a movable bed condition, effects of sand grains and bore wave on the deposit were examined. Yamamoto et al. (2016) showed deposition range varied with sand grain sizes. In addition, it is revealed that the range fluctuated by number of waves and wave period. The measurements of velocity and water level showed that flow was clearly different near shoreline and in run-up area. Large velocity by return flow was affected the amount of sand deposit near shoreline. When a cutoff wall was installed on the slope, the amount of sand deposit repeatedly increased and decreased. Especially, sand deposit increased where velocity decreased. Takahashi et al. (1999) adapted the proposed model into Kesennuma bay when the 1960 Chilean tsunami arrived, although the amount of sand transportation was underestimated. The cause of the underestimation is inferred that the velocity of this model was underestimated. A relationship between velocity and sediment transport has to be studied in detail, but

  10. Modelling heavy-ion energy deposition in extended media

    International Nuclear Information System (INIS)

    Mishustin, I.; Pshenichnov, I.; Greiner, W.; Mishustin, I.; Pshenichnov, I.

    2010-01-01

    We present recent developments of the Monte Carlo model for heavy-ion therapy (MCHIT), which is currently based on the Geant4 tool-kit of version 9.2. The major advancement of the model concerns the modelling of violent fragmentation reactions by means of the Fermi break-up model, which is used to simulate decays of hot fragments created after the first stage of nucleus-nucleus collisions. By means of MCHIT we study the dose distributions from therapeutic beams of carbon nuclei in tissue-like materials, like water and PMMA. The contributions to the total dose from primary beam nuclei and from charged secondary fragments produced in nuclear fragmentation reactions are calculated. The build-up of secondary fragments along the beam axis is calculated and compared with available experimental data. Finally, we demonstrate the impact of violent multifragment decays on energy distributions of secondary neutrons produced by carbon nuclei in water. (authors)

  11. Modelling heavy-ion energy deposition in extended media

    Energy Technology Data Exchange (ETDEWEB)

    Mishustin, I.; Pshenichnov, I.; Greiner, W. [Frankfurt Institute for Advanced Studies, J.-W. Goethe University, Frankfurt am Main (Germany); Mishustin, I. [Kurchatov Institute, Russian Research Center, Moscow (Russian Federation); Pshenichnov, I. [Institute for Nuclear Research, Russian Academy of Science, Moscow (Russian Federation)

    2010-10-15

    We present recent developments of the Monte Carlo model for heavy-ion therapy (MCHIT), which is currently based on the Geant4 tool-kit of version 9.2. The major advancement of the model concerns the modelling of violent fragmentation reactions by means of the Fermi break-up model, which is used to simulate decays of hot fragments created after the first stage of nucleus-nucleus collisions. By means of MCHIT we study the dose distributions from therapeutic beams of carbon nuclei in tissue-like materials, like water and PMMA. The contributions to the total dose from primary beam nuclei and from charged secondary fragments produced in nuclear fragmentation reactions are calculated. The build-up of secondary fragments along the beam axis is calculated and compared with available experimental data. Finally, we demonstrate the impact of violent multifragment decays on energy distributions of secondary neutrons produced by carbon nuclei in water. (authors)

  12. Alkali deposits found in biomass power plants: A preliminary investigation of their extent and nature. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Miles, T.R.; Miles, T.R. Jr. [Miles (Thomas R.), Portland, OR (United States); Baxter, L.L. [Sandia National Labs., Livermore, CA (United States). Combustion Research Facility; Bryers, R.W. [Foster Wheeler Development Corp., Livingston, NJ (United States); Jenkins, B.M. [California Univ., Davis, CA (United States); Oden, L.L. [Bureau of Mines, Albany, OR (United States). Albany Research Center

    1995-04-15

    Alkali in the ash of annual crop biomass fuels creates serious fouling and slagging in conventional boilers. Even with the use of sorbents and other additives, power plants can only fire limited amounts of these fuels in combination with wood. The National Renewable Energy Laboratory (NREL), US Department of Energy, and the biomass power industry carried out eight full-scale firing tests and several laboratory experiments to study the nature and occurrence of deposits with the goal of increasing the quantities of these biofuels that can be used. This report describes the results of the laboratory and power plant tests that included: tracking and analyzing fuels and deposits by various methods; recording operating conditions; and extensive laboratory testing. The paper describes the occurrence of deposits, fuel and deposit analyses, boiler design and operation, fouling and slagging indicators, and recommendations. 37 refs., 41 figs., 17 tabs.

  13. Stability of phase transformation models for Ti-6Al-4V under cyclic thermal loading imposed during laser metal deposition

    Science.gov (United States)

    Klusemann, Benjamin; Bambach, Markus

    2018-05-01

    Processing conditions play a crucial role for the resulting microstructure and properties of the material. In particular, processing materials under non-equilibrium conditions can lead to a remarkable improvement of the final properties [1]. Additive manufacturing represents a specific process example considered in this study. Models for the prediction of residual stresses and microstructure in additive manufacturing processes, such as laser metal deposition, are being developed with huge efforts to support the development of materials and processes as well as to support process design [2-4]. Since the microstructure predicted after each heating and cooling cycle induced by the moving laser source enters the phase transformation kinetics and microstucture evolution of the subsequent heating and cooling cycle, a feed-back loop for the microstructure calculation is created. This calculation loop may become unstable so that the computed microstructure and related properties become very sensitive to small variations in the input parameters, e.g. thermal conductivity. In this paper, a model for phase transformation in Ti-6Al-4V, originally proposed by Charles Murgau et al. [5], is adopted and minimal adjusted concerning the decomposition of the martensite phase are made. This model is subsequently used to study the changes in the predictions of the different phase volume fractions during heating and cooling under the conditions of laser metal deposition with respect to slight variations in the thermal process history.

  14. Models for estimation of tree volume in the miombo woodlands of ...

    African Journals Online (AJOL)

    Volume of trees is an important parameter in forest management, but only volume models with limited geographical and tree size coverage have previously been developed for Tanzanian miombo woodlands. This study developed models for estimating total, merchantable stem and branches volume applicable for the entire ...

  15. INTRA/Mod3.2. Manual and Code Description. Volume I - Physical Modelling

    International Nuclear Information System (INIS)

    Andersson, Jenny; Edlund, O.; Hermann, J.; Johansson, Lise-Lotte

    1999-01-01

    The INTRA Manual consists of two volumes. Volume I of the manual is a thorough description of the code INTRA, the Physical modelling of INTRA and the ruling numerical methods and volume II, the User's Manual is an input description. This document, the Physical modelling of INTRA, contains code characteristics, integration methods and applications

  16. INTRA/Mod3.2. Manual and Code Description. Volume I - Physical Modelling

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Jenny; Edlund, O; Hermann, J; Johansson, Lise-Lotte

    1999-01-01

    The INTRA Manual consists of two volumes. Volume I of the manual is a thorough description of the code INTRA, the Physical modelling of INTRA and the ruling numerical methods and volume II, the User`s Manual is an input description. This document, the Physical modelling of INTRA, contains code characteristics, integration methods and applications

  17. The effects of the forward speed and air volume of an air-assisted sprayer on spray deposition in tendone trained vineyards

    Directory of Open Access Journals (Sweden)

    Simone Pascuzzi

    2013-12-01

    Full Text Available This paper reports the results of spray application trials in a tendone trained vineyard in order to evaluate the influence of forward speed and air volume on the foliar deposition of plant protection products (PPPs, maintaining roughly constant the volume applied. The trials used an air-assisted sprayer with a centrifugal fan and 4+4 adjustable fan-shaped diffusers, each with a nozzle-holder group. A full factorial experimental design was implemented, with three forward speeds and two airflow rates, organised with a randomised complete block design including three replicates. In order to consider the influence of canopy development, the tests (one spray application for each replicate of a mixture containing a water-soluble food dye as a tracer were replicated during two phenological stages: i the end of flowering; and ii berry touch. Leaves were picked at random from the canopy after each spray treatment, and foliar PPP deposition was evaluated using a spectrophotometer. This analysis of foliar deposition showed that the airflow rates produced by the fan were unsuitable for the dense canopy typical of this type of vineyard. However, the special shape of the diffusers may make this sprayer effective if the main objective of pesticide applications in tendone trained table grape vineyards is to control bunch diseases.

  18. Volume-based geometric modeling for radiation transport calculations

    International Nuclear Information System (INIS)

    Li, Z.; Williamson, J.F.

    1992-01-01

    Accurate theoretical characterization of radiation fields is a valuable tool in the design of complex systems, such as linac heads and intracavitary applicators, and for generation of basic dose calculation data that is inaccessible to experimental measurement. Both Monte Carlo and deterministic solutions to such problems require a system for accurately modeling complex 3-D geometries that supports ray tracing, point and segment classification, and 2-D graphical representation. Previous combinatorial approaches to solid modeling, which involve describing complex structures as set-theoretic combinations of simple objects, are limited in their ease of use and place unrealistic constraints on the geometric relations between objects such as excluding common boundaries. A new approach to volume-based solid modeling has been developed which is based upon topologically consistent definitions of boundary, interior, and exterior of a region. From these definitions, FORTRAN union, intersection, and difference routines have been developed that allow involuted and deeply nested structures to be described as set-theoretic combinations of ellipsoids, elliptic cylinders, prisms, cones, and planes that accommodate shared boundaries. Line segments between adjacent intersections on a trajectory are assigned to the appropriate region by a novel sorting algorithm that generalizes upon Siddon's approach. Two 2-D graphic display tools are developed to help the debugging of a given geometric model. In this paper, the mathematical basis of our system is described, it is contrasted to other approaches, and examples are discussed

  19. Simulation of size-dependent aerosol deposition in a realistic model of the upper human airways

    NARCIS (Netherlands)

    Frederix, E.M.A.; Kuczaj, Arkadiusz K.; Nordlund, Markus; Belka, M.; Lizal, F.; Elcner, J.; Jicha, M.; Geurts, Bernardus J.

    An Eulerian internally mixed aerosol model is used for predictions of deposition inside a realistic cast of the human upper airways. The model, formulated in the multi-species and compressible framework, is solved using the sectional discretization of the droplet size distribution function to

  20. 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...

  1. 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.

  2. 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

  3. Development of modelling and forecasting in geology. (Volume 1)

    International Nuclear Information System (INIS)

    Afzali, H.; Fourniguet, J.; Peaudecerf, P.

    1990-01-01

    To assess the long-term safety of radioactive waste disposal systems, validation of predictive models is essential and large efforts should be given to barriers, particularly geologic barriers. This work appears in the form of four volumes, the subject of the first part is described below. Soils and rocks erosion depends upon climate, relief, lithology and human activities (deforesting). In the world, mechanical erosion is evaluated from 5 to 8 cm per 1000 years (mean denudation ratio). Rocks weathering solubilize chemical elements in the running water and rocks fracturation becomes more easily under erosion effects. Alteration front progress is 0.3-3 cm per 1000 years in temperate zones and 4-7 cm per 1000 years in tropical zones. 5 figs., 14 tabs., 80 refs

  4. Thermokinetic Modeling of Phase Transformation in the Laser Powder Deposition Process

    Science.gov (United States)

    Foroozmehr, Ehsan; Kovacevic, Radovan

    2009-08-01

    A finite element model coupled with a thermokinetic model is developed to predict the phase transformation of the laser deposition of AISI 4140 on a substrate with the same material. Four different deposition patterns, long-bead, short-bead, spiral-in, and spiral-out, are used to cover a similar area. Using a finite element model, the temperature history of the laser powder deposition (LPD) process is determined. The martensite transformation as well as martensite tempering is considered to calculate the final fraction of martensite, ferrite, cementite, ɛ-carbide, and retained austenite. Comparing the surface hardness topography of different patterns reveals that path planning is a critical parameter in laser surface modification. The predicted results are in a close agreement with the experimental results.

  5. A refined methodology for modeling volume quantification performance in CT

    Science.gov (United States)

    Chen, Baiyu; Wilson, Joshua; Samei, Ehsan

    2014-03-01

    The utility of CT lung nodule volume quantification technique depends on the precision of the quantification. To enable the evaluation of quantification precision, we previously developed a mathematical model that related precision to image resolution and noise properties in uniform backgrounds in terms of an estimability index (e'). The e' was shown to predict empirical precision across 54 imaging and reconstruction protocols, but with different correlation qualities for FBP and iterative reconstruction (IR) due to the non-linearity of IR impacted by anatomical structure. To better account for the non-linearity of IR, this study aimed to refine the noise characterization of the model in the presence of textured backgrounds. Repeated scans of an anthropomorphic lung phantom were acquired. Subtracted images were used to measure the image quantum noise, which was then used to adjust the noise component of the e' calculation measured from a uniform region. In addition to the model refinement, the validation of the model was further extended to 2 nodule sizes (5 and 10 mm) and 2 segmentation algorithms. Results showed that the magnitude of IR's quantum noise was significantly higher in structured backgrounds than in uniform backgrounds (ASiR, 30-50%; MBIR, 100-200%). With the refined model, the correlation between e' values and empirical precision no longer depended on reconstruction algorithm. In conclusion, the model with refined noise characterization relfected the nonlinearity of iterative reconstruction in structured background, and further showed successful prediction of quantification precision across a variety of nodule sizes, dose levels, slice thickness, reconstruction algorithms, and segmentation software.

  6. 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.

  7. Modeling Approach for Estimating Co-Produced Water Volumes and Saltwater Disposal Volumes in Oklahoma

    Science.gov (United States)

    Murray, K. E.

    2016-12-01

    Management of produced fluids has become an important issue in Oklahoma because large volumes of saltwater are co-produced with oil and gas, and disposed into saltwater disposal wells at high rates. Petroleum production increased from 2009-2015, especially in central and north-central Oklahoma where the Mississippian and Hunton zones were redeveloped using horizontal wells and dewatering techniques that have led to a disproportional increase in produced water volumes. Improved management of co-produced water, including desalination for beneficial reuse and decreased saltwater disposal volumes, is only possible if spatial and temporal trends can be defined and related to the producing zones. It is challenging to quantify the volumes of co-produced water by region or production zone because co-produced water volumes are generally not reported. Therefore, the goal of this research is to estimate co-produced water volumes for 2008-present with an approach that can be replicated as petroleum production shifts to other regions. Oil and gas production rates from subsurface zones were multiplied by ratios of H2O:oil and H2O:gas for the respective zones. Initial H2O:oil and H2O:gas ratios were adjusted/calibrated, by zone, to maximize correlation of county-scale produced H2O estimates versus saltwater disposal volumes from 2013-2015. These calibrated ratios were then used to compute saltwater disposal volumes from 2008-2012 because of apparent data gaps in reported saltwater disposal volumes during that timeframe. This research can be used to identify regions that have the greatest need for produced water treatment systems. The next step in management of produced fluids is to explore optimal energy-efficient strategies that reduce deleterious effects.

  8. The Limit Deposit Velocity model, a new approach

    Directory of Open Access Journals (Sweden)

    Miedema Sape A.

    2015-12-01

    Full Text Available In slurry transport of settling slurries in Newtonian fluids, it is often stated that one should apply a line speed above a critical velocity, because blow this critical velocity there is the danger of plugging the line. There are many definitions and names for this critical velocity. It is referred to as the velocity where a bed starts sliding or the velocity above which there is no stationary bed or sliding bed. Others use the velocity where the hydraulic gradient is at a minimum, because of the minimum energy consumption. Most models from literature are one term one equation models, based on the idea that the critical velocity can be explained that way.

  9. Modeled Urea Distribution Volume and Mortality in the HEMO Study

    Science.gov (United States)

    Greene, Tom; Depner, Thomas A.; Levin, Nathan W.; Chertow, Glenn M.

    2011-01-01

    Summary Background and objectives In the Hemodialysis (HEMO) Study, observed small decreases in achieved equilibrated Kt/Vurea were noncausally associated with markedly increased mortality. Here we examine the association of mortality with modeled volume (Vm), the denominator of equilibrated Kt/Vurea. Design, setting, participants, & measurements Parameters derived from modeled urea kinetics (including Vm) and blood pressure (BP) were obtained monthly in 1846 patients. Case mix–adjusted time-dependent Cox regressions were used to relate the relative mortality hazard at each time point to Vm and to the change in Vm over the preceding 6 months. Mixed effects models were used to relate Vm to changes in intradialytic systolic BP and to other factors at each follow-up visit. Results Mortality was associated with Vm and change in Vm over the preceding 6 months. The association between change in Vm and mortality was independent of vascular access complications. In contrast, mortality was inversely associated with V calculated from anthropometric measurements (Vant). In case mix–adjusted analysis using Vm as a time-dependent covariate, the association of mortality with Vm strengthened after statistical adjustment for Vant. After adjustment for Vant, higher Vm was associated with slightly smaller reductions in intradialytic systolic BP and with risk factors for mortality including recent hospitalization and reductions in serum albumin concentration and body weight. Conclusions An increase in Vm is a marker for illness and mortality risk in hemodialysis patients. PMID:21511841

  10. Alligator Rivers Analogue project. Hydrogeological modelling. Final Report - Volume 6

    International Nuclear Information System (INIS)

    Townley, L.R.; Trefry, M.G.; Barr, A.D.; Braumiller, S.

    1992-01-01

    This volume describes hydrogeological modelling carried out as part of the Alligator Rivers Analogue Project. Hydrogeology has played a key integrating role in the Project, largely because water movement is believed to have controlled the evolution of the Koongarra uranium Orebody and therefore affects field observations of all types at all scales. Aquifer testing described uses the concept of transmissivity in its interpretation of aquifer response to pumping. The concept of an aquifer, a layer transmitting significant quantities of water in a mainly horizontal direction, seems hard to accept in an environment as heterogeneous as that at Koongarra. But modelling of aquifers both in one dimension and two dimensionally in plan has contributed significantly to our understanding of the site. A one-dimensional model with three layers (often described as a quasi two dimensional model) was applied to flow between the Fault and Koongarra Creek. Being a transient model, this model was able to show that reverse flows can indeed occur back towards the Fault, but only if there is distributed recharge over the orebody as well as a mechanism for the Fault, or a region near the Fault, to remove water from the simulated cross-section. The model also showed clearly that the response of the three-layered system, consisting of a highly weathered zone, a fractured transmissive zone and a less conductive lower schist zone, is governed mainly by the transmissivity and storage coefficient of the middle layer. The storage coefficient of the higher layer has little effect. A two-dimensional model in plan used a description of anisotropy to show that reverse flows can also occur even without a conducting Fault. Modelling of a three-dimensional region using discrete fractures showed that it is certainly possible to simulate systems like that observed at Koongarra, but that large amounts of data are probably needed to obtain realistic descriptions of the fracture networks. Inverse modelling

  11. Alligator Rivers Analogue project. Hydrogeological modelling. Final Report - Volume 6

    Energy Technology Data Exchange (ETDEWEB)

    Townley, L R; Trefry, M G; Barr, A D [CSIRO Div of Water Resources, PO Wembley, WA (Australia); Braumiller, S [Univ of Arizona, Tucson, AZ (United States). Dept of Hydrology and Water Resources; Kawanishi, M [Central Research Institute of Electric Power Industry, Abiko-Shi, Chiba-Ken (Japan); and others

    1993-12-31

    This volume describes hydrogeological modelling carried out as part of the Alligator Rivers Analogue Project. Hydrogeology has played a key integrating role in the Project, largely because water movement is believed to have controlled the evolution of the Koongarra uranium Orebody and therefore affects field observations of all types at all scales. Aquifer testing described uses the concept of transmissivity in its interpretation of aquifer response to pumping. The concept of an aquifer, a layer transmitting significant quantities of water in a mainly horizontal direction, seems hard to accept in an environment as heterogeneous as that at Koongarra. But modelling of aquifers both in one dimension and two dimensionally in plan has contributed significantly to our understanding of the site. A one-dimensional model with three layers (often described as a quasi two dimensional model) was applied to flow between the Fault and Koongarra Creek. Being a transient model, this model was able to show that reverse flows can indeed occur back towards the Fault, but only if there is distributed recharge over the orebody as well as a mechanism for the Fault, or a region near the Fault, to remove water from the simulated cross-section. The model also showed clearly that the response of the three-layered system, consisting of a highly weathered zone, a fractured transmissive zone and a less conductive lower schist zone, is governed mainly by the transmissivity and storage coefficient of the middle layer. The storage coefficient of the higher layer has little effect. A two-dimensional model in plan used a description of anisotropy to show that reverse flows can also occur even without a conducting Fault. Modelling of a three-dimensional region using discrete fractures showed that it is certainly possible to simulate systems like that observed at Koongarra, but that large amounts of data are probably needed to obtain realistic descriptions of the fracture networks. Inverse modelling

  12. Maintenance Personnel Performance Simulation (MAPPS) model: description of model content, structure, and sensitivity testing. Volume 2

    International Nuclear Information System (INIS)

    Siegel, A.I.; Bartter, W.D.; Wolf, J.J.; Knee, H.E.

    1984-12-01

    This volume of NUREG/CR-3626 presents details of the content, structure, and sensitivity testing of the Maintenance Personnel Performance Simulation (MAPPS) model that was described in summary in volume one of this report. The MAPPS model is a generalized stochastic computer simulation model developed to simulate the performance of maintenance personnel in nuclear power plants. The MAPPS model considers workplace, maintenance technician, motivation, human factors, and task oriented variables to yield predictive information about the effects of these variables on successful maintenance task performance. All major model variables are discussed in detail and their implementation and interactive effects are outlined. The model was examined for disqualifying defects from a number of viewpoints, including sensitivity testing. This examination led to the identification of some minor recalibration efforts which were carried out. These positive results indicate that MAPPS is ready for initial and controlled applications which are in conformity with its purposes

  13. Development and test of models in the natural analogue studies of the Cigar Lake uranium deposit

    Energy Technology Data Exchange (ETDEWEB)

    Liu Jinsong

    1995-06-01

    In the model of steady-state near-field mass transport, the model concepts are essentially the same as those in the models developed for a nuclear waste repository. The validity of the model is tested against known helium release. The models shows that the release of Uranium is negligibly low, the release of sulfate is roughly balanced by the release of dissolved hydrogen, indicating possible water radiolysis. The release of radionuclides is in agreement with field observations. In the model of radiation energy deposition, the issue of water radiolysis is addressed directly by calculating the radiation energy deposited in the pore water in the ore body. In the test of the models of coupled solute transport with geochemical reactions, the observed hematisation in the clay halo adjacent to the ore is simulated. The model results show that, at a certain rate of oxidant production, hematite can possibly precipitate in the clay adjacent to the ore body, as observed. The model results also reveal a threshold of oxidant production rate for hematisation. In general, the three models are capable of predicting the most prominent features observed in the deposit. All models point to a certain extent of water radiolysis in the ore body. In addition, the existence of a negligibly permeable clay halo and the presence of reducing minerals like pyrite in the ore and nearby are of vital importance for the preservation of the Uranium ore. 107 refs, 7 figs, 5 tabs.

  14. Development and test of models in the natural analogue studies of the Cigar Lake uranium deposit

    International Nuclear Information System (INIS)

    Liu Jinsong.

    1995-06-01

    In the model of steady-state near-field mass transport, the model concepts are essentially the same as those in the models developed for a nuclear waste repository. The validity of the model is tested against known helium release. The models shows that the release of Uranium is negligibly low, the release of sulfate is roughly balanced by the release of dissolved hydrogen, indicating possible water radiolysis. The release of radionuclides is in agreement with field observations. In the model of radiation energy deposition, the issue of water radiolysis is addressed directly by calculating the radiation energy deposited in the pore water in the ore body. In the test of the models of coupled solute transport with geochemical reactions, the observed hematisation in the clay halo adjacent to the ore is simulated. The model results show that, at a certain rate of oxidant production, hematite can possibly precipitate in the clay adjacent to the ore body, as observed. The model results also reveal a threshold of oxidant production rate for hematisation. In general, the three models are capable of predicting the most prominent features observed in the deposit. All models point to a certain extent of water radiolysis in the ore body. In addition, the existence of a negligibly permeable clay halo and the presence of reducing minerals like pyrite in the ore and nearby are of vital importance for the preservation of the Uranium ore. 107 refs, 7 figs, 5 tabs

  15. 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....

  16. 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.

  17. 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.

  18. Sensitivity of the modelled deposition of Caesium-137 from the Fukushima Dai-ichi nuclear power plant to the wet deposition parameterisation in NAME

    International Nuclear Information System (INIS)

    Leadbetter, Susan J.; Hort, Matthew C.; Jones, Andrew R.; Webster, Helen N.; Draxler, Roland R.

    2015-01-01

    This paper describes an investigation into the impact of different meteorological data sets and different wet scavenging coefficients on the model predictions of radionuclide deposits following the accident at the Fukushima Dai-ichi nuclear power plant in March 2011. Three separate operational meteorological data sets, the UK Met Office global meteorology, the ECMWF global meteorology and the Japan Meteorological Agency (JMA) mesoscale meteorology as well as radar rainfall analyses from JMA were all used as inputs to the UK Met Office's dispersion model NAME (the Numerical Atmospheric-dispersion Modelling Environment). The model predictions of Caesium-137 deposits based on these meteorological models all showed good agreement with observations of deposits made in eastern Japan with correlation coefficients ranging from 0.44 to 0.80. Unexpectedly the NAME run using radar rainfall data had a lower correlation coefficient (R = 0.66), when compared to observations, than the run using the JMA mesoscale model rainfall (R = 0.76) or the run using ECMWF met data (R = 0.80). Additionally the impact of modifying the wet scavenging coefficients used in the parameterisation of wet deposition was investigated. The results showed that modifying the scavenging parameters had a similar impact to modifying the driving meteorology on the rank calculated from comparing the modelled and observed deposition

  19. 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

  20. Subretinal Pigment Epithelial Deposition of Drusen Components Including Hydroxyapatite in a Primary Cell Culture Model.

    Science.gov (United States)

    Pilgrim, Matthew G; Lengyel, Imre; Lanzirotti, Antonio; Newville, Matt; Fearn, Sarah; Emri, Eszter; Knowles, Jonathan C; Messinger, Jeffrey D; Read, Russell W; Guidry, Clyde; Curcio, Christine A

    2017-02-01

    Extracellular deposits containing hydroxyapatite, lipids, proteins, and trace metals that form between the basal lamina of the RPE and the inner collagenous layer of Bruch's membrane are hallmarks of early AMD. We examined whether cultured RPE cells could produce extracellular deposits containing all of these molecular components. Retinal pigment epithelium cells isolated from freshly enucleated porcine eyes were cultured on Transwell membranes for up to 6 months. Deposit composition and structure were characterized using light, fluorescence, and electron microscopy; synchrotron x-ray diffraction and x-ray fluorescence; secondary ion mass spectroscopy; and immunohistochemistry. Apparently functional primary RPE cells, when cultured on 10-μm-thick inserts with 0.4-μm-diameter pores, can produce sub-RPE deposits that contain hydroxyapatite, lipids, proteins, and trace elements, without outer segment supplementation, by 12 weeks. The data suggest that sub-RPE deposit formation is initiated, and probably regulated, by the RPE, as well as the loss of permeability of the Bruch's membrane and choriocapillaris complex associated with age and early AMD. This cell culture model of early AMD lesions provides a novel system for testing new therapeutic interventions against sub-RPE deposit formation, an event occurring well in advance of the onset of vision loss.

  1. Comparison of a model vapor deposited glass films to equilibrium glass films

    Science.gov (United States)

    Flenner, Elijah; Berthier, Ludovic; Charbonneau, Patrick; Zamponi, Francesco

    Vapor deposition of particles onto a substrate held at around 85% of the glass transition temperature can create glasses with increased density, enthalpy, kinetic stability, and mechanical stability compared to an ordinary glass created by cooling. It is estimated that an ordinary glass would need to age thousands of years to reach the kinetic stability of a vapor deposited glass, and a natural question is how close to the equilibrium is the vapor deposited glass. To understand the process, algorithms akin to vapor deposition are used to create simulated glasses that have a higher kinetic stability than their annealed counterpart, although these glasses may not be well equilibrated either. Here we use novel models optimized for a swap Monte Carlo algorithm in order to create equilibrium glass films and compare their properties with those of glasses obtained from vapor deposition algorithms. This approach allows us to directly assess the non-equilibrium nature of vapor-deposited ultrastable glasses. Simons Collaboration on Cracking the Glass Problem and NSF Grant No. DMR 1608086.

  2. EXPURT - a model for evaluating exposure from radioactive material deposited in the urban environment

    International Nuclear Information System (INIS)

    Crick, M.J.; Brown, J.

    1990-06-01

    This model, EXPURT (EXPosure from Urban Radionuclide Transfer), is described in detail. The model simulates the movement of activity deposited on various surfaces in the urban environment and, by taking into account the shielding properties of buildings and the habits of the population, evaluates the external doses to members of the population living in such urban environments, as a function of time after deposition. One of the other advantages of EXPURT over simpler models is that it can be used to assess the possible dose reductions that might be achieved by various decontamination techniques; for example, it can estimate the effectiveness of decontaminating roof surfaces alone in reducing exposure to individuals living in an urban environment. Sensitivity/uncertainty studies have been performed whereby those parameters contributing most to remaining uncertainty in the model's predictions of dose and dose rates were identified. Predictions of the EXPURT model were compared with those from a simpler external dose model in use at NRPB. (author)

  3. 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.

  4. 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.

  5. 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.

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

    Directory of Open Access Journals (Sweden)

    Curtisha D. Travis

    2013-08-01

    Full Text Available 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 based on collocation discretization in time, resulting in an unambiguous definition of film growth-per-cycle (gpc. A key finding of this study is that unintended chemical vapor deposition conditions can mask regions of operation that would otherwise correspond to ideal saturating ALD operation. The use of the simulator for assisting in process design decisions is presented.

  7. An analytical–numerical model of laser direct metal deposition track and microstructure formation

    International Nuclear Information System (INIS)

    Ahsan, M Naveed; Pinkerton, Andrew J

    2011-01-01

    Multiple analytical and numerical models of the laser metal deposition process have been presented, but most rely on sequential solution of the energy and mass balance equations or discretization of the problem domain. Laser direct metal deposition is a complex process involving multiple interdependent processes which can be best simulated using a fully coupled mass-energy balance solution. In this work a coupled analytical–numerical solution is presented. Sub-models of the powder stream, quasi-stationary conduction in the substrate and powder assimilation into the area of the substrate above the liquidus temperature are combined. An iterative feedback loop is used to ensure mass and energy balances are maintained at the melt pool. The model is verified using Ti–6Al–4V single track deposition, produced with a coaxial nozzle and a diode laser. The model predictions of local temperature history, the track profile and microstructure scale show good agreement with the experimental results. The model is a useful industrial aid and alternative to finite element methods for selecting the parameters to use for laser direct metal deposition when separate geometric and microstructural outcomes are required

  8. Carbonatite and alkaline intrusion-related rare earth element deposits–A deposit model

    Science.gov (United States)

    Verplanck, Philip L.; Van Gosen, Bradley S.

    2011-01-01

    The rare earth elements are not as rare in nature as their name implies, but economic deposits with these elements are not common and few deposits have been large producers. In the past 25 years, demand for rare earth elements has increased dramatically because of their wide and diverse use in high-technology applications. Yet, presently the global production and supply of rare earth elements come from only a few sources. China produces more than 95 percent of the world's supply of rare earth elements. Because of China's decision to restrict exports of these elements, the price of rare earth elements has increased and industrial countries are concerned about supply shortages. As a result, understanding the distribution and origin of rare earth elements deposits, and identifying and quantifying our nation's rare earth elements resources have become priorities. Carbonatite and alkaline intrusive complexes, as well as their weathering products, are the primary sources of rare earth elements. The general mineral deposit model summarized here 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. Carbonatite and alkaline intrusion-related REE deposits are discussed together because of their spatial association, common enrichment in incompatible elements, and similarities in genesis. A wide variety of commodities have been exploited from carbonatites and alkaline igneous rocks, such as rare earth elements, niobium, phosphate, titanium, vermiculite, barite, fluorite, copper, calcite, and zirconium. Other enrichments include manganese, strontium, tantalum, thorium, vanadium, and uranium.

  9. Chemical vapor deposition. Volume 2. 1975--July, 1978 (a bibliography with abstracts). Report for 1975--July 1978

    International Nuclear Information System (INIS)

    Smith, M.F.

    1978-07-01

    Research on chemical vapor deposition of carbon, carbides, ceramics, metals, and glasses are cited. Applications of this process include optical coatings, semiconducting films, laser materials, solar cells, composite fabrication, and nuclear reactor material fabrication. The physical, mechanical, and chemical properties of these coatings are covered

  10. Modeling of thermal, electronic, hydrodynamic, and dynamic deposition processes for pulsed-laser deposition of thin films

    International Nuclear Information System (INIS)

    Liu, C.L.; LeBoeuf, J.N.; Wood, R.F.; Geohegan, D.B.; Donato, J.M.; Chen, K.R.; Puretzky, A.A.

    1994-11-01

    Various physical processes during laser ablation of solids for pulsed-laser deposition (PLD) are studied using a variety of computational techniques. In the course of the authors combined theoretical and experimental effort, they have been trying to work on as many aspects of PLD processes as possible, but with special focus on the following areas: (a) the effects of collisional interactions between the particles in the plume and in the background on the evolving flow field and on thin film growth, (b) interactions between the energetic particles and the growing thin films and their effects on film quality, (c) rapid phase transformations through the liquid and vapor phases under possibly nonequilibrium thermodynamic conditions induced by laser-solid interactions, (d) breakdown of the vapor into a plasma in the early stages of ablation through both electronic and photoionization processes, (c) hydrodynamic behavior of the vapor/plasma during and after ablation. The computational techniques used include finite difference (FD) methods, particle-in-cell model, and atomistic simulations using molecular dynamics (MD) techniques

  11. 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 Gaussian tilting plume principle was applied inside the stayed track. The model was developed on one set of field experiments using a flat-fan nozzle and validated against another set of field experiments using an air-induction nozzle. The vertical spray-drift profile was measured using hair curlers...... at increasing distances. The vertical concentration profile downwind has a maximum just above the ground in our observations and calculations. The model accounts for the meteorological conditions, droplet ejection velocity and size spectrum. Model validation led to an R2 value of 0.78, and 91% of the calculated...

  12. In vitro surfactant and perfluorocarbon aerosol deposition in a neonatal physical model of the upper conducting airways.

    Directory of Open Access Journals (Sweden)

    Estibalitz Goikoetxea

    Full Text Available OBJECTIVE: Aerosol delivery holds potential to release surfactant or perfluorocarbon (PFC to the lungs of neonates with respiratory distress syndrome with minimal airway manipulation. Nevertheless, lung deposition in neonates tends to be very low due to extremely low lung volumes, narrow airways and high respiratory rates. In the present study, the feasibility of enhancing lung deposition by intracorporeal delivery of aerosols was investigated using a physical model of neonatal conducting airways. METHODS: The main characteristics of the surfactant and PFC aerosols produced by a nebulization system, including the distal air pressure and air flow rate, liquid flow rate and mass median aerodynamic diameter (MMAD, were measured at different driving pressures (4-7 bar. Then, a three-dimensional model of the upper conducting airways of a neonate was manufactured by rapid prototyping and a deposition study was conducted. RESULTS: The nebulization system produced relatively large amounts of aerosol ranging between 0.3±0.0 ml/min for surfactant at a driving pressure of 4 bar, and 2.0±0.1 ml/min for distilled water (H2Od at 6 bar, with MMADs between 2.61±0.1 µm for PFD at 7 bar and 10.18±0.4 µm for FC-75 at 6 bar. The deposition study showed that for surfactant and H2Od aerosols, the highest percentage of the aerosolized mass (∼65% was collected beyond the third generation of branching in the airway model. The use of this delivery system in combination with continuous positive airway pressure set at 5 cmH2O only increased total airway pressure by 1.59 cmH2O at the highest driving pressure (7 bar. CONCLUSION: This aerosol generating system has the potential to deliver relatively large amounts of surfactant and PFC beyond the third generation of branching in a neonatal airway model with minimal alteration of pre-set respiratory support.

  13. Modelling pollutant deposition to vegetation: scaling down from the canopy to the biochemical level

    International Nuclear Information System (INIS)

    Taylor, G.E. Jr.; Constable, J.V.H.

    1994-01-01

    In the atmosphere, pollutants exist in either the gas, particle or liquid (rain and cloud water) phase. The most important gas-phase pollutants from a biological or ecological perspective are oxides of nitrogen (nitrogen dioxide, nitric acid vapor), oxides of sulfur (sulfur dioxide), ammonia, tropospheric ozone and mercury vapor. For liquid or particle phase pollutants, the suite of pollutants is varied and includes hydrogen ion, multiple heavy metals, and select anions. For many of these pollutants, plant canopies are a major sink within continental landscapes, and deposition is highly dependent on the (i) physical form or phase of the pollutant, (ii) meteorological conditions above and within the plant canopy, and (iii) physiological or biochemical properties of the leaf, both on the leaf surface and within the leaf interior. In large measure, the physical and chemical processes controlling deposition at the meteorological and whole-canopy levels are well characterized and have been mathematically modelled. In contrast, the processes operating on the leaf surface and within the leaf interior are not well understood and are largely specific for individual pollutants. The availability of process-level models to estimate deposition is discussed briefly at the canopy and leaf level; however, the majority of effort is devoted to modelling deposition at the leaf surface and leaf interior using the two-layer stagnant film model. This model places a premium on information of a physiological and biochemical nature, and highlights the need to distinguish clearly between the measurements of atmospheric chemistry and the physiologically effective exposure since the two may be very dissimilar. A case study of deposition in the Los Angeles Basin is used to demonstrate the modelling approach, to present the concept of exposure dynamics in the atmosphere versus that in the leaf interior, and to document the principle that most forest canopies are exposed to multiple chemical

  14. 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

  15. Main geologic characteristics and metallogenic models of uranium deposits in Zhejiang

    International Nuclear Information System (INIS)

    Tang Qitao

    2000-01-01

    Uranium resources in Zhejiang is abundant with numerous mineralization types. According to the genesis they can be classified into: sedimentary-reworking type, hydrothermal type and infiltration type. The author briefly describes main geologic characteristics and metallogenic models of different type uranium deposits

  16. 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.

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

    Science.gov (United States)

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

  18. 3D printing of CNT- and graphene-based conductive polymer nanocomposites by fused deposition modeling

    NARCIS (Netherlands)

    Gnanasekaran, K.; Heijmans, T.; van Bennekom, S.; Woldhuis, H.; Wijnia, S.; de With, G.; Friedrich, H.

    2017-01-01

    Fused deposition modeling (FDM) is limited by the availability of application specific functional materials. Here we illustrate printing of non-conventional polymer nanocomposites (CNT- and graphene-based polybutylene terephthalate (PBT)) on a commercially available desktop 3D printer leading toward

  19. Impact of enhanced ozone deposition and halogen chemistry on model performance

    Science.gov (United States)

    In this study, an enhanced ozone deposition scheme due to the interaction of iodide in sea-water and atmospheric ozone and the detailed chemical reactions of organic and inorganic halogen species are incorporated into the hemispheric Community Multiscale Air Quality model. Prelim...

  20. 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...

  1. 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

  2. The field experiments and model of the natural dust deposition effects on photovoltaic module efficiency.

    Science.gov (United States)

    Jaszczur, Marek; Teneta, Janusz; Styszko, Katarzyna; Hassan, Qusay; Burzyńska, Paulina; Marcinek, Ewelina; Łopian, Natalia

    2018-04-20

    The maximisation of the efficiency of the photovoltaic system is crucial in order to increase the competitiveness of this technology. Unfortunately, several environmental factors in addition to many alterable and unalterable factors can significantly influence the performance of the PV system. Some of the environmental factors that depend on the site have to do with dust, soiling and pollutants. In this study conducted in the city centre of Kraków, Poland, characterised by high pollution and low wind speed, the focus is on the evaluation of the degradation of efficiency of polycrystalline photovoltaic modules due to natural dust deposition. The experimental results that were obtained demonstrated that deposited dust-related efficiency loss gradually increased with the mass and that it follows the exponential. The maximum dust deposition density observed for rainless exposure periods of 1 week exceeds 300 mg/m 2 and the results in efficiency loss were about 2.1%. It was observed that efficiency loss is not only mass-dependent but that it also depends on the dust properties. The small positive effect of the tiny dust layer which slightly increases in surface roughness on the module performance was also observed. The results that were obtained enable the development of a reliable model for the degradation of the efficiency of the PV module caused by dust deposition. The novelty consists in the model, which is easy to apply and which is dependent on the dust mass, for low and moderate naturally deposited dust concentration (up to 1 and 5 g/m 2 and representative for many geographical regions) and which is applicable to the majority of cases met in an urban and non-urban polluted area can be used to evaluate the dust deposition-related derating factor (efficiency loss), which is very much sought after by the system designers, and tools used for computer modelling and system malfunction detection.

  3. Volume dependence of the melting temperature for alkali metals with Debye's model

    International Nuclear Information System (INIS)

    Soma, T.; Kagaya, H.M.; Nishigaki, M.

    1983-01-01

    Using the volume dependence of the Grueneisen constant at higher temperatures, the volume effect on the melting temperature of alkali metals is studied by Lindeman's melting law and Debye's model. The obtained melting curve increases as a function of the compressed volume and shows the maximum of the melting point at the characteristic volume. The resultant data are qualitatively in agreement with the observed tendency for alkali metals. (author)

  4. A preliminary deposit model for lithium-cesium-tantalum (LCT) pegmatites

    Science.gov (United States)

    Bradley, Dwight; McCauley, Andrew

    2013-01-01

    This report is part of an effort by the U.S. Geological Survey to update existing mineral deposit models and to develop new ones. We emphasize practical aspects of pegmatite geology that might directly or indirectly help in exploration for lithium-cesium-tantalum (LCT) pegmatites, or for assessing regions for pegmatite-related mineral resource potential. These deposits are an important link in the world’s supply chain of rare and strategic elements, accounting for about one-third of world lithium production, most of the tantalum, and all of the cesium.

  5. System of the creation of a model for the coal deposit, and the subsequent

    Directory of Open Access Journals (Sweden)

    Staněk František

    1996-09-01

    Full Text Available In the paper, methodics of creating a model for different type of the coal deposit is described, including the processing of reserves text and graphic outputs. It is also useful in cases of the deposit with a great number of seams of various thicknesses that is heavily tectonically disturbed and divided into tectonic blocks. The development of seams is variable in both the thickness and quality. Splitting of the seams occurs, separate benches are formed and, on the contrary, connected into one seam.

  6. 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.

  7. Charge deposition model for investigating SE-microdose effect in trench power MOSFETs

    International Nuclear Information System (INIS)

    Wan Xin; Zhou Weisong; Liu Daoguang; Bo Hanliang; Xu Jun

    2015-01-01

    It was demonstrated that heavy ions can induce large current—voltage (I–V) characteristics shift in commercial trench power MOSFETs, named single event microdose effect (SE-microdose effect). A model is presented to describe this effect. This model calculates the charge deposition by a single heavy ion hitting oxide and the subsequent charge transport under an electric field. Holes deposited at the SiO 2 /Si interface by a Xe ion are calculated by using this model. The calculated results were then used in Sentaurus TCAD software to simulate a trench power MOSFET's I–V curve shift after a Xe ion has hit it. The simulation results are consistent with the related experiment's data. In the end, several factors which affect the SE-microdose effect in trench power MOSFETs are investigated by using this model. (paper)

  8. Charge deposition model for investigating SE-microdose effect in trench power MOSFETs

    Science.gov (United States)

    Xin, Wan; Weisong, Zhou; Daoguang, Liu; Hanliang, Bo; Jun, Xu

    2015-05-01

    It was demonstrated that heavy ions can induce large current—voltage (I-V) characteristics shift in commercial trench power MOSFETs, named single event microdose effect (SE-microdose effect). A model is presented to describe this effect. This model calculates the charge deposition by a single heavy ion hitting oxide and the subsequent charge transport under an electric field. Holes deposited at the SiO2/Si interface by a Xe ion are calculated by using this model. The calculated results were then used in Sentaurus TCAD software to simulate a trench power MOSFET's I-V curve shift after a Xe ion has hit it. The simulation results are consistent with the related experiment's data. In the end, several factors which affect the SE-microdose effect in trench power MOSFETs are investigated by using this model.

  9. 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.

  10. Statistical shape modeling based renal volume measurement using tracked ultrasound

    Science.gov (United States)

    Pai Raikar, Vipul; Kwartowitz, David M.

    2017-03-01

    Autosomal dominant polycystic kidney disease (ADPKD) is the fourth most common cause of kidney transplant worldwide accounting for 7-10% of all cases. Although ADPKD usually progresses over many decades, accurate risk prediction is an important task.1 Identifying patients with progressive disease is vital to providing new treatments being developed and enable them to enter clinical trials for new therapy. Among other factors, total kidney volume (TKV) is a major biomarker predicting the progression of ADPKD. Consortium for Radiologic Imaging Studies in Polycystic Kidney Disease (CRISP)2 have shown that TKV is an early, and accurate measure of cystic burden and likely growth rate. It is strongly associated with loss of renal function.3 While ultrasound (US) has proven as an excellent tool for diagnosing the disease; monitoring short-term changes using ultrasound has been shown to not be accurate. This is attributed to high operator variability and reproducibility as compared to tomographic modalities such as CT and MR (Gold standard). Ultrasound has emerged as one of the standout modality for intra-procedural imaging and with methods for spatial localization has afforded us the ability to track 2D ultrasound in physical space which it is being used. In addition to this, the vast amount of recorded tomographic data can be used to generate statistical shape models that allow us to extract clinical value from archived image sets. In this work, we aim at improving the prognostic value of US in managing ADPKD by assessing the accuracy of using statistical shape model augmented US data, to predict TKV, with the end goal of monitoring short-term changes.

  11. 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.

  12. A Theoretically Consistent Framework for Modelling Lagrangian Particle Deposition in Plant Canopies

    Science.gov (United States)

    Bailey, Brian N.; Stoll, Rob; Pardyjak, Eric R.

    2018-06-01

    We present a theoretically consistent framework for modelling Lagrangian particle deposition in plant canopies. The primary focus is on describing the probability of particles encountering canopy elements (i.e., potential deposition), and provides a consistent means for including the effects of imperfect deposition through any appropriate sub-model for deposition efficiency. Some aspects of the framework draw upon an analogy to radiation propagation through a turbid medium with which to develop model theory. The present method is compared against one of the most commonly used heuristic Lagrangian frameworks, namely that originally developed by Legg and Powell (Agricultural Meteorology, 1979, Vol. 20, 47-67), which is shown to be theoretically inconsistent. A recommendation is made to discontinue the use of this heuristic approach in favour of the theoretically consistent framework developed herein, which is no more difficult to apply under equivalent assumptions. The proposed framework has the additional advantage that it can be applied to arbitrary canopy geometries given readily measurable parameters describing vegetation structure.

  13. In-Swath Spray Deposition Characteristics of a Low Drift Nozzle for Low Volume Aerial Application - Preliminary Results.

    Science.gov (United States)

    CP flat-fan nozzles with selectable tips were evaluated for droplet spectra and coverage using water sensitive papers placed in the spray swath. This study used low application volumes (1, 2, and 3 GPA) at a certain spray application height as measured precisely by laser mounted in the aircraft. No...

  14. 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.

  15. Multiscale modeling, simulations, and experiments of coating growth on nanofibers. Part II. Deposition

    International Nuclear Information System (INIS)

    Buldum, A.; Clemons, C.B.; Dill, L.H.; Kreider, K.L.; Young, G.W.; Zheng, X.; Evans, E.A.; Zhang, G.; Hariharan, S.I.

    2005-01-01

    This work is Part II of an integrated experimental/modeling investigation of a procedure to coat nanofibers and core-clad nanostructures with thin-film materials using plasma-enhanced physical vapor deposition. In the experimental effort, electrospun polymer nanofibers are coated with aluminum materials under different operating conditions to observe changes in the coating morphology. This procedure begins with the sputtering of the coating material from a target. Part I [J. Appl. Phys. 98, 044303 (2005)] focused on the sputtering aspect and transport of the sputtered material through the reactor. That reactor level model determines the concentration field of the coating material. This field serves as input into the present species transport and deposition model for the region surrounding an individual nanofiber. The interrelationships among processing factors for the transport and deposition are investigated here from a detailed modeling approach that includes the salient physical and chemical phenomena. Solution strategies that couple continuum and atomistic models are used. At the continuum scale, transport dynamics near the nanofiber are described. At the atomic level, molecular dynamics (MD) simulations are used to study the deposition and sputtering mechanisms at the coating surface. Ion kinetic energies and fluxes are passed from the continuum sheath model to the MD simulations. These simulations calculate sputtering and sticking probabilities that in turn are used to calculate parameters for the continuum transport model. The continuum transport model leads to the definition of an evolution equation for the coating-free surface. This equation is solved using boundary perturbation and level set methods to determine the coating morphology as a function of operating conditions

  16. 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.

  17. RESEARCH OF COMPETITION IN DEPOSIT MARKET OF UKRAINE BASED ON THE PANZAR-ROSSE MODEL

    Directory of Open Access Journals (Sweden)

    Iryna Didenko

    2016-11-01

    Full Text Available The problem in an adequate assessment of the level of competition in the banking market has prompted researchers to search constantly some new methods. The most famous of them were later successfully adapted to the banking market, are a models of Bresnahan, Panzar-Rosse, Bertrand, Iwat, Monti-Klein-Modesto Barros and others. In Ukraine, the process of assessing the level of competition in the banking sector is very relevant, in line with the recent reforms of particular relevance and distribution. Regarding the domestic deposit market, there is a shortage of qualitative analysis of this issue, unlike foreign practice. Therefore this study we try to solve this problem. The key goal of researchers in this study is in a detailed analysis to identify the important factors which make influence on the allocated markets, in particular on lending and deposit rates. Based on these factors there could be implemented internal adjustment processes taking place in the markets. The purpose of the article is to determine the level of competition in the deposit market of Ukraine in 2006-2015 basing on nonstructural Panzar- Rosse model and identify key factors that affect this level. Methodology. To research the level of competition in the deposit market of Ukraine the Panzar-Rosse model was used, in which separate 11 models were built using the integrated tool “Multiple regression” in the software package of statistics analysis STATISTICA. The input data in the model was presented with the information on financial performance of Ukrainian banks during ten years from 01.01.2005 till 01.01.2015. Results of this research showed that in Ukrainian deposit market there is a monopolistic competition, as proved by the calculated values of H-statistics index. The year of 2008, in the context of the global economic crisis, was marked as an unbalanced period for deposit market of Ukraine. Practical implications. Knowing the current state of competition level in the

  18. Indoor aerosol modeling for assessment of exposure and respiratory tract deposited dose

    Science.gov (United States)

    Hussein, Tareq; Wierzbicka, Aneta; Löndahl, Jakob; Lazaridis, Mihalis; Hänninen, Otto

    2015-04-01

    Air pollution is one of the major environmental problems that influence people's health. Exposure to harmful particulate matter (PM) occurs both outdoors and indoors, but while people spend most of their time indoors, the indoor exposures tend to dominate. Moreover, higher PM concentrations due to indoor sources and tightness of indoor environments may substantially add to the outdoor originating exposures. Empirical and real-time assessment of human exposure is often impossible; therefore, indoor aerosol modeling (IAM) can be used as a superior method in exposure and health effects studies. This paper presents a simple approach in combining available aerosol-based modeling techniques to evaluate the real-time exposure and respiratory tract deposited dose based on particle size. Our simple approach consists of outdoor aerosol data base, IAM simulations, time-activity pattern data-base, physical-chemical properties of inhaled aerosols, and semi-empirical deposition fraction of aerosols in the respiratory tract. These modeling techniques allow the characterization of regional deposited dose in any metric: particle mass, particle number, and surface area. The first part of this presentation reviews recent advances in simple mass-balance based modeling methods that are needed in analyzing the health relevance of indoor exposures. The second part illustrates the use of IAM in the calculations of exposure and deposited dose. Contrary to previous methods, the approach presented is a real-time approach and it goes beyond the exposure assessment to provide the required information for the health risk assessment, which is the respiratory tract deposited dose. This simplified approach is foreseen to support epidemiological studies focusing on exposures originating from both indoor and outdoor sources.

  19. 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

  20. Volcanogenic massive sulfide occurrence model: Chapter C in Mineral deposit models for resource assessment

    Science.gov (United States)

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

    2012-01-01

    Volcanogenic massive sulfide deposits, also known as volcanic-hosted massive sulfide, volcanic-associated massive sulfide, or seafloor massive sulfide deposits, are important sources of copper, zinc, lead, gold, and silver (Cu, Zn, Pb, Au, and Ag). These deposits form at or near the seafloor where circulating hydrothermal fluids driven by magmatic heat are quenched through mixing with bottom waters or porewaters in near-seafloor lithologies. Massive sulfide lenses vary widely in shape and size and may be podlike or sheetlike. They are generally stratiform and may occur as multiple lenses.

  1. Modeling high-density-plasma deposition of SiO{sub 2} in SiH{sub 4}/O{sub 2}/Ar

    Energy Technology Data Exchange (ETDEWEB)

    Meeks, E.; Larson, R.S. [Sandia National Labs., Livermore, CA (United States); Ho, P.; Apblett, C. [Sandia National Labs., Albuquerque, NM (United States); Han, S.M.; Edelberg, E.; Aydil, E. [Univ. of California, Santa Barbara, CA (United States)

    1997-03-01

    The authors have compiled sets of gas-phase and surface reactions for use in modeling plasma-enhanced chemical vapor deposition of silicon dioxide from silane, oxygen and argon gas mixtures in high-density-plasma reactors. They have applied the reaction mechanisms to modeling three different kinds of high-density plasma deposition chambers, and tested them by comparing model predictions to a variety of experimental measurements. The model simulates a well mixed reactor by solving global conservation equations averaged across the reactor volume. The gas-phase reaction mechanism builds from fundamental electron-impact cross section data available in the literature, and also includes neutral-molecule, ion-ion, and ion-molecule reaction paths. The surface reaction mechanism is based on insight from attenuated total-reflection Fourier-transform infrared spectroscopy experiments. This mechanism describes the adsorption of radical species on an oxide surface, ion-enhanced reactions leading to species desorption from the surface layer, radical abstractions competing for surface sites, and direct energy-dependent ion sputtering of the oxide material. Experimental measurements of total ion densities, relative radical densities as functions of plasma operating conditions, and net deposition-rate have been compared to model predictions to test and modify the chemical kinetics mechanisms. Results show good quantitative agreement between model predictions and experimental measurements.

  2. Adjusting particle-size distributions to account for aggregation in tephra-deposit model forecasts

    Science.gov (United States)

    Mastin, Larry G.; Van Eaton, Alexa; Durant, A.J.

    2016-01-01

    Volcanic ash transport and dispersion (VATD) models are used to forecast tephra deposition during volcanic eruptions. Model accuracy is limited by the fact that fine-ash aggregates (clumps into clusters), thus altering patterns of deposition. In most models this is accounted for by ad hoc changes to model input, representing fine ash as aggregates with density ρagg, and a log-normal size distribution with median μagg and standard deviation σagg. Optimal values may vary between eruptions. To test the variance, we used the Ash3d tephra model to simulate four deposits: 18 May 1980 Mount St. Helens; 16–17 September 1992 Crater Peak (Mount Spurr); 17 June 1996 Ruapehu; and 23 March 2009 Mount Redoubt. In 192 simulations, we systematically varied μagg and σagg, holding ρagg constant at 600 kg m−3. We evaluated the fit using three indices that compare modeled versus measured (1) mass load at sample locations; (2) mass load versus distance along the dispersal axis; and (3) isomass area. For all deposits, under these inputs, the best-fit value of μagg ranged narrowly between  ∼  2.3 and 2.7φ (0.20–0.15 mm), despite large variations in erupted mass (0.25–50 Tg), plume height (8.5–25 km), mass fraction of fine ( discrete process that is insensitive to eruptive style or magnitude. This result offers the potential for a simple, computationally efficient parameterization scheme for use in operational model forecasts. Further research may indicate whether this narrow range also reflects physical constraints on processes in the evolving cloud.

  3. Partial molar volume of proteins studied by the three-dimensional reference interaction site model theory.

    Science.gov (United States)

    Imai, Takashi; Kovalenko, Andriy; Hirata, Fumio

    2005-04-14

    The three-dimensional reference interaction site model (3D-RISM) theory is applied to the analysis of hydration effects on the partial molar volume of proteins. For the native structure of some proteins, the partial molar volume is decomposed into geometric and hydration contributions using the 3D-RISM theory combined with the geometric volume calculation. The hydration contributions are correlated with the surface properties of the protein. The thermal volume, which is the volume of voids around the protein induced by the thermal fluctuation of water molecules, is directly proportional to the accessible surface area of the protein. The interaction volume, which is the contribution of electrostatic interactions between the protein and water molecules, is apparently governed by the charged atomic groups on the protein surface. The polar atomic groups do not make any contribution to the interaction volume. The volume differences between low- and high-pressure structures of lysozyme are also analyzed by the present method.

  4. 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

  5. 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

  6. DIAPARK. A theoretical model for radiological assessments after short-term release and deposition of radionuclides

    International Nuclear Information System (INIS)

    Eklund, J.; Mueller, H.; Proehl, G.; Jacob, P.

    1995-05-01

    The DIAPARK program package is an enhancement of the ECOSYS-87 model for radioecological assessment, developed by GSF. The program version of the ECOSYS-87 model covers primarily the results and information derived from measurements performed after the Chernobyl reactor accident. Much importance has been attached to making the model fit for customized adjustment by modification of model parameters in order to be able to take into account the various conditions in various regions. The program package allows calculation of the deposition and interception, food contamination (as determined by plant contamination, contamination of animal products, radioactivity levels changed by storage and processing), doses resulting from ingestion and inhalation, and external exposure. (HP) [de

  7. 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...... and the open filters are surface piercing. Due to the few experimental data sets on sediment transport inside of rock layers, a sediment transport formulation has been proposed based on a matching between the numerical model and experimental data on the profile deformation inside an open filter. The rock layer...

  8. Evaluating Ammonia Deposition Rates for Deciduous Forest using Measurements and Modelling

    DEFF Research Database (Denmark)

    Hansen, Kristina; Geels, Camilla; Hertel, Ole

    ). However, there are relatively few datasets of atmospheric NH3 fluxes available for forests which can contribute verifying model results. The atmospheric dry deposition of NH3 for the beech (Fagus sylvatica) forest, Lille Bøgeskov, in Sorø, Denmark, is investigated using the high resolution...... these impacts, quantifying the magnitude of the NH3 flux in the biosphere atmosphere system is essential. Model simulations using the Danish Ammonia Modelling System (DAMOS) have recently indicated that particular forest ecosystems are exposed to critical load exceedances of N (Geels et al., not yet submitted......-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...

  9. Differential Deposition of Fluorescently Tagged Cholesterol on Commercial Contact Lenses Using a Novel In Vitro Eye Model.

    Science.gov (United States)

    Walther, Hendrik; Phan, Chau-Minh; Subbaraman, Lakshman N; Jones, Lyndon

    2018-04-01

    We evaluate the differences in lipid uptake and penetration in daily disposable (DD) contact lenses (CL) using a conventional "in-vial" method compared to a novel in vitro eye model. The penetration of fluorescently labelled 22-(N-(7-Nitrobenz-2-Oxa-1,3-Diazol-4-yl)Amino)-23,24-Bisnor-5-Cholen-3beta-Ol (NBD)-cholesterol on three silicone hydrogel (SH) and four conventional hydrogel (CH) DD CLs were investigated. CLs were incubated for 4 and 12 hours in a vial, containing 3.5 mL artificial tear solution (ATS), or were mounted on an in vitro eye-blink platform designed to simulate physiologic tear flow (2 mL/24 hours), tear volume and "simulated" blinking. Subsequently, CLs were analyzed using laser scanning confocal microscopy and ImageJ. Penetration depth and fluorescence intensities of NBD-cholesterol varied between the incubation methods as well as lens materials. Using the traditional vial incubation method, NBD-cholesterol uptake occurred equally on both sides of all lens materials. However, using our eye-blink model, cholesterol penetration was observed primarily on the anterior surface of the CLs. In general, SH lenses showed higher intensities of NBD-cholesterol than CH materials. The traditional "in-vial" incubation method exposes the CLs to an excessively high amount of ATS, which results in an overestimation for cholesterol deposition. Our model, which incorporates important ocular factors, such as intermittent air exposure, small tear volume, and physiological tear flow between blinks, provides a more natural environment for in vitro lens incubation. In vitro measurements of CLs are a common approach to predict their interactions and performance on the eye. Traditional methods, however, are rudimentary. Therefore, this study presents a novel in vitro model to evaluate CLs, which consequently will enhance elucidations of the interactions between CLs and the eye.

  10. Itataia ore deposit - Caracterization of the massif according alteration/argilization and estimation of material volume inside a pit

    International Nuclear Information System (INIS)

    Alcantara e Silva, J.R. de.

    1986-01-01

    This paper sumarizes the geotechnically characterization of the Itataia ore deposit according to the relationship rock alteration/argilization. Through this charaterization it was defined three types of material related to the degree of alteration and argillization: Type I (fresh or pratically fresh and little or monargillized material); Type II (partially altered and argillized material). The new geological syntesis and iformation, together with seismic parameters allowed to a material classification according to the scarificability, and important factor in the costs of an open pit mine. (author) [pt

  11. Modelling stomatal ozone flux and deposition to grassland communities across Europe

    International Nuclear Information System (INIS)

    Ashmore, M.R.; Bueker, P.; Emberson, L.D.; Terry, A.C.; Toet, S.

    2007-01-01

    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 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

  12. 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

  13. Lacustrine-humate model for primary uranium ore deposits, Grants Uranium Region, New Mexico

    International Nuclear Information System (INIS)

    Turner-Peterson, C.E.

    1985-01-01

    Two generations of uranium ore, primary and redistributed, occur in fluvial sandstones of the Upper Jurassic Morrison Formation in the San Juan basin; the two stages of ore formation can be related to the hydrologic history of the basin. Primary ore formed soon after Morrison deposition, in the Late Jurassic to Early Cretaceous, and a model, the lacustrine-humate model, is offered that views primary mineralization as a diagenetic event related to early pore fluid evolution. The basic premise is that the humate, a pore-filling organic material closely associated with primary ore, originated as humic acids dissolved in pore waters of greenish-gray lacustrine mudstones deposited in the mud-flat facies of the Brushy Basin Member and similar K shale beds in the Westwater Canyon Member. During compaction associated with early burial, formation water expelled from lacustrine mudstone units carried these humic acids into adjacent sandstone beds where the organics precipitated, forming the humate deposits that concentrated uranium. During the Tertiary, much later in the hydrologic history of the basin, when Jurassic sediments were largely compacted, oxygenated ground water flowed basinward from uplifted basin margins. This invasion of Morrison sandstone beds by oxidizing ground waters redistributed uranium from primary ores along redox boundaries, forming ore deposits that resemble roll-front-type uranium ores. 11 figures

  14. 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.

  15. 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

  16. Micron-sized and submicron-sized aerosol deposition in a new ex vivo preclinical model.

    Science.gov (United States)

    Perinel, Sophie; Leclerc, Lara; Prévôt, Nathalie; Deville, Agathe; Cottier, Michèle; Durand, Marc; Vergnon, Jean-Michel; Pourchez, Jérémie

    2016-07-07

    The knowledge of where particles deposit in the respiratory tract is crucial for understanding the health effects associated with inhaled drug particles. An ex vivo study was conducted to assess regional deposition patterns (thoracic vs. extrathoracic) of radioactive polydisperse aerosols with different size ranges [0.15 μm-0.5 μm], [0.25 μm-1 μm] and [1 μm-9 μm]. SPECT/CT analyses were performed complementary in order to assess more precisely the regional deposition of aerosols within the pulmonary tract. Experiments were set using an original respiratory tract model composed of a human plastinated head connected to an ex vivo porcine pulmonary tract. The model was ventilated by passive expansion, simulating pleural depressions. Aerosol was administered during nasal breathing. Planar scintigraphies allowed to calculate the deposited aerosol fractions for particles in the three size ranges from sub-micron to micron The deposited fractions obtained, for thoracic vs. extra-thoracic regions respectively, were 89 ± 4 % vs. 11 ± 4 % for [0.15 μm-0.5 μm], 78 ± 5 % vs. 22 ± 5 % for [0.25 μm-1 μm] and 35 ± 11 % vs.65 ± 11 % for [1 μm-9 μm]. Results obtained with this new ex vivo respiratory tract model are in good agreement with the in vivo data obtained in studies with baboons and humans.

  17. 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.

  18. Uncertainty modelling and analysis of volume calculations based on a regular grid digital elevation model (DEM)

    Science.gov (United States)

    Li, Chang; Wang, Qing; Shi, Wenzhong; Zhao, Sisi

    2018-05-01

    The accuracy of earthwork calculations that compute terrain volume is critical to digital terrain analysis (DTA). The uncertainties in volume calculations (VCs) based on a DEM are primarily related to three factors: 1) model error (ME), which is caused by an adopted algorithm for a VC model, 2) discrete error (DE), which is usually caused by DEM resolution and terrain complexity, and 3) propagation error (PE), which is caused by the variables' error. Based on these factors, the uncertainty modelling and analysis of VCs based on a regular grid DEM are investigated in this paper. Especially, how to quantify the uncertainty of VCs is proposed by a confidence interval based on truncation error (TE). In the experiments, the trapezoidal double rule (TDR) and Simpson's double rule (SDR) were used to calculate volume, where the TE is the major ME, and six simulated regular grid DEMs with different terrain complexity and resolution (i.e. DE) were generated by a Gauss synthetic surface to easily obtain the theoretical true value and eliminate the interference of data errors. For PE, Monte-Carlo simulation techniques and spatial autocorrelation were used to represent DEM uncertainty. This study can enrich uncertainty modelling and analysis-related theories of geographic information science.

  19. 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

  20. The relationship between trading volumes, number of transactions, and stock volatility in GARCH models

    Science.gov (United States)

    Takaishi, Tetsuya; Chen, Ting Ting

    2016-08-01

    We examine the relationship between trading volumes, number of transactions, and volatility using daily stock data of the Tokyo Stock Exchange. Following the mixture of distributions hypothesis, we use trading volumes and the number of transactions as proxy for the rate of information arrivals affecting stock volatility. The impact of trading volumes or number of transactions on volatility is measured using the generalized autoregressive conditional heteroscedasticity (GARCH) model. We find that the GARCH effects, that is, persistence of volatility, is not always removed by adding trading volumes or number of transactions, indicating that trading volumes and number of transactions do not adequately represent the rate of information arrivals.

  1. Applying ARIMA model for annual volume time series of the Magdalena River

    Directory of Open Access Journals (Sweden)

    Gloria Amaris

    2017-04-01

    Conclusions: The simulated results obtained with the ARIMA model compared to the observed data showed a fairly good adjustment of the minimum and maximum magnitudes. This allows concluding that it is a good tool for estimating minimum and maximum volumes, even though this model is not capable of simulating the exact behaviour of an annual volume time series.

  2. Open Burn/Open Detonation Dispersion Model (OBODM) User's Guide. Volume I. User's Instructions

    National Research Council Canada - National Science Library

    Bjorklund, Jay

    1998-01-01

    ...) of obsolete munitions and solid propellants. OBODM uses loud/plume rise, dispersion, and deposition algorithms taken from existing models for instantaneous and quasi-continuous sources to predict the downwind transport and dispersion...

  3. 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.

  4. 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

  5. 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)

    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.

  6. Identification of mineralized zones in the Zardu area, Kushk SEDEX deposit (Central Iran, based on geological and multifractal modeling

    Directory of Open Access Journals (Sweden)

    Dahooei Ahmad Heidari

    2016-02-01

    Full Text Available The aim of this paper is to delineate the different lead–zinc mineralized zones in the Zardu area of the Kushk zinc–lead stratabound SEDEX deposit, Central Iran, through concentration–volume (C–V modeling of geological and lithogeochemical drillcore data. The geological model demonstrated that the massive sulfide and pyrite+dolomite ore types as main rock types hosting mineralization. The C–V fractal modeling used lead, zinc and iron geochemical data to outline four types of mineralized zones, which were then compared to the mineralized rock types identified in the geological model. ‘Enriched’ mineralized zones contain lead and zinc values higher than 6.93% and 19.95%, respectively, with iron values lower than 12.02%. Areas where lead and zinc values were higher than 1.58% and 5.88%, respectively, and iron grades lower than 22% are labelled “high-grade” mineralized zones, and these zones are linked to massive sulfide and pyrite+dolomite lithologies of the geological model. Weakly mineralized zones, labelled ‘low-grade’ in the C– V model have 0–0.63% lead, 0–3.16% zinc and > 30.19% iron, and are correlated to those lithological units labeled as gangue in the geological model, including shales and dolomites, pyritized dolomites. Finally, a log-ratio matrix was employed to validate the results obtained and check correlations between the geological and fractal modeling. Using this method, a high overall accuracy (OA was confirmed for the correlation between the enriched and high-grade mineralized zones and two lithological units — the massive sulfide and pyrite+dolomite ore types.

  7. 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.

  8. 2D modeling of direct laser metal deposition process using a finite particle method

    Science.gov (United States)

    Anedaf, T.; Abbès, B.; Abbès, F.; Li, Y. M.

    2018-05-01

    Direct laser metal deposition is one of the material additive manufacturing processes used to produce complex metallic parts. A thorough understanding of the underlying physical phenomena is required to obtain a high-quality parts. In this work, a mathematical model is presented to simulate the coaxial laser direct deposition process tacking into account of mass addition, heat transfer, and fluid flow with free surface and melting. The fluid flow in the melt pool together with mass and energy balances are solved using the Computational Fluid Dynamics (CFD) software NOGRID-points, based on the meshless Finite Pointset Method (FPM). The basis of the computations is a point cloud, which represents the continuum fluid domain. Each finite point carries all fluid information (density, velocity, pressure and temperature). The dynamic shape of the molten zone is explicitly described by the point cloud. The proposed model is used to simulate a single layer cladding.

  9. 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.

  10. 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

  11. Three dimensional modeling of depositional geometries. A case study from Tofane Group (Dolomites, Italy).

    Science.gov (United States)

    Gattolin, G.; Franceschi, M.; Breda, A.; Teza, G.; Preto, N.

    2012-04-01

    At the end of the Early Carnian, the Carnian Pluvial Event (CPE) resulted in a major crisis of carbonate factories. The sharp change in carbonate production lead to a dramatic modifications in depositional geometries. Steep clinoforms of the high-relief pre-crisis carbonate platforms were replaced by low-angle ramps. Spatial characters of depositional geometries can be decisive in identifying the genesis of geological bodies. We here show how 3D modeling techniques can be applied to help in quantifying and highlighting their variations. As case study we considered two outcrops in the Tofane Group (Dolomites, Italy). The first outcrop (bottom of southern walls of Tofana di Rozes) exposes a platform-to-basin transect of pre- and post-crisis platforms, the second (Dibona hut) a clinostratified carbonate body deposited during the Carnian crisis. Outcrop conditions at both sites, with vertical and hardly accessible walls, make the field tracing of depositional geometries particularly challenging. Line drawing on high resolution pictures can help (e.g. for clinoforms), but its use for quantification is hampered by perspective deformation. Three dimensional acquisition and modeling allow to retrieve the true spatial characters of sedimentary bodies in these outcrops. The geometry of the carbonate body at Dibona (~ 15000 sqm) was acquired with terrestrial LiDAR, while for Tofana photogrammetric techniques were applied because of the extension of the outcrop itself (~ 240000 sqm) and the lack of suitable points of view for terrestrial laser scanning. At Tofana, field observations reveal the presence of tens-hundreds m large carbonate mounds grown on a pre-existing inclined surface, intercalated with skeletal carbonates and siltites-arenites. This system rapidly evolves into a carbonate-clastic ramp. Photogrammetric topography acquisition permitted to place and visualize geological features in a three dimensional frame, thus obtaining a conceptual sedimentological model. A 3

  12. Experimental Setup for Ultrasonic-Assisted Desktop Fused Deposition Modeling System

    OpenAIRE

    Maidin, S.; Muhamad, M. K.; Pei, Eujin

    2014-01-01

    Fused deposition modeling (FDM) is an additive manufacturing (AM) process that has been used in various manufacturing fields. However, the drawback of FDM is poor surface finish of part produced, leading to surface roughness and requires hand finishing. In this study, ultrasonic technology will be integrated into a desktop FDM system. Ultrasound has been applied in various conventional machining process and shows good machined surface finish. However, very little research regarding the applic...

  13. Improvement of Surface Finish by Multiple Piezoelectric Transducers in Fused Deposition Modelling

    OpenAIRE

    A. S. Mohamed; S. Maidin; S. B. Mohamed; M. K. Muhamad; J.H. U. Wong; W. F. A. Romlee

    2016-01-01

    Additive Manufacturing (AM) which embrace as a new range technology of creating and producing end user parts in term of adding material layer by layer to create solid object from 3D CAD data. AM in particular Fused Deposition Modelling (FDM) used (ABS) thermoplastic have shown the most popular among the industry as its technology can print complex geometrical part without human intervention and tools. However, FDM fierce enemy whereas the common problem of stair-stepping, which means that sea...

  14. 3D printing of CNT- and graphene-based conductive polymer nanocomposites by fused deposition modeling

    OpenAIRE

    Gnanasekaran, K.; Heijmans, T.; van Bennekom, S.; Woldhuis, H.; Wijnia, S.; de With, G.; Friedrich, H.

    2017-01-01

    Fused deposition modeling (FDM) is limited by the availability of application specific functional materials. Here we illustrate printing of non-conventional polymer nanocomposites (CNT- and graphene-based polybutylene terephthalate (PBT)) on a commercially available desktop 3D printer leading toward printing of electrically conductive structures. The printability, electrical conductivity and mechanical stability of the polymer nanocomposites before and after 3D printing was evaluated. The res...

  15. Modeling of Atmospheric Transport and Deposition of Heavy Metals in the Katowice Province

    OpenAIRE

    Uliasz, M.; Olendrzynski, K.

    1996-01-01

    A large part of Poland's heavy industry, notably hard coal mining, ferrous and nonferrous metallurgy and power generation, is located in the Katowice province. Therefore, this heavy industrialized region, which is populated by four million people, experiences considerable problems with air pollution. In the METKAT study launched by the International Institute for Applied Systems Analysis we attempt to model atmospheric depositions of arsenic (As), cadmium (Cd), lead (Pb) and zinc (Zn) which a...

  16. Carbon footprint estimator, phase II : volume I - GASCAP model & volume II - technical appendices [technical brief].

    Science.gov (United States)

    2014-03-01

    This study resulted in the development of the GASCAP model (the Greenhouse Gas Assessment : Spreadsheet for Transportation Capital Projects). This spreadsheet model provides a user-friendly interface for determining the greenhouse gas (GHG) emissions...

  17. How relevant is the deposition of mercury onto snowpacks? – Part 2: A modeling study

    Directory of Open Access Journals (Sweden)

    D. Durnford

    2012-10-01

    Full Text Available An unknown fraction of mercury that is deposited onto snowpacks is revolatilized to the atmosphere. Determining the revolatilized fraction is important since mercury that enters the snowpack meltwater may be converted to highly toxic bioaccumulating methylmercury. In this study, we present a new dynamic physically-based snowpack/meltwater model for mercury that is suitable for large-scale atmospheric models for mercury. It represents the primary physical and chemical processes that determine the fate of mercury deposited onto snowpacks. The snowpack/meltwater model was implemented in Environment Canada's atmospheric mercury model GRAHM. For the first time, observed snowpack-related mercury concentrations are used to evaluate and constrain an atmospheric mercury model. We find that simulated concentrations of mercury in both snowpacks and the atmosphere's surface layer agree closely with observations. The simulated concentration of mercury in both in the top 30 cm and the top 150 cm of the snowpack, averaged over 2005–2009, is predominantly below 6 ng L−1 over land south of 66.5° N but exceeds 18 ng L−1 over sea ice in extensive areas of the Arctic Ocean and Hudson Bay. The average simulated concentration of mercury in snowpack meltwater runoff tends to be higher on the Russian/European side (>20 ng L−1 of the Arctic Ocean than on the Canadian side (<10 ng L−1. The correlation coefficient between observed and simulated monthly mean atmospheric surface-level gaseous elemental mercury (GEM concentrations increased significantly with the inclusion of the new snowpack/meltwater model at two of the three stations (midlatitude, subarctic studied and remained constant at the third (arctic. Oceanic emissions are postulated to produce the observed summertime maximum in concentrations of surface-level atmospheric GEM at Alert in the Canadian Arctic and to generate the summertime volatility observed in

  18. 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.

  19. RELAP5/MOD3 code manual. Volume 4, Models and correlations

    International Nuclear Information System (INIS)

    1995-08-01

    The RELAP5 code has been developed for best-estimate transient simulation of light water reactor coolant systems during postulated accidents. The code models the coupled behavior of the reactor coolant system and the core for loss-of-coolant accidents and operational transients such as anticipated transient without scram, loss of offsite power, loss of feedwater, and loss of flow. A generic modeling approach is used that permits simulating a variety of thermal hydraulic systems. Control system and secondary system components are included to permit modeling of plant controls, turbines, condensers, and secondary feedwater systems. RELAP5/MOD3 code documentation is divided into seven volumes: Volume I presents modeling theory and associated numerical schemes; Volume II details instructions for code application and input data preparation; Volume III presents the results of developmental assessment cases that demonstrate and verify the models used in the code; Volume IV discusses in detail RELAP5 models and correlations; Volume V presents guidelines that have evolved over the past several years through the use of the RELAP5 code; Volume VI discusses the numerical scheme used in RELAP5; and Volume VII presents a collection of independent assessment calculations

  20. Transportation Sector Model of the National Energy Modeling System. Volume 2 -- Appendices: Part 3

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-01-01

    This Appendix consists of two unpublished reports produced by Energy and Environmental Analysis, Inc., under contract to Oak Ridge National Laboratory. These two reports formed the basis for the subsequent development of the Fuel Economy Model described in Volume 1. They are included in order to document more completely the efforts undertaken to construct a comprehensive model of automobile fuel economy. The supplemental reports are as follows: Supplement 1--Documentation Attributes of Technologies to Improve Automotive Fuel Economy; Supplement 2--Analysis of the Fuel Economy Boundary for 2010 and Comparison to Prototypes.

  1. Diameter structure modeling and the calculation of plantation volume of black poplar clones

    Directory of Open Access Journals (Sweden)

    Andrašev Siniša

    2004-01-01

    Full Text Available A method of diameter structure modeling was applied in the calculation of plantation (stand volume of two black poplar clones in the section Aigeiros (Duby: 618 (Lux and S1-8. Diameter structure modeling by Weibull function makes it possible to calculate the plantation volume by volume line. Based on the comparison of the proposed method with the existing methods, the obtained error of plantation volume was less than 2%. Diameter structure modeling and the calculation of plantation volume by diameter structure model, by the regularity of diameter distribution, enables a better analysis of the production level and assortment structure and it can be used in the construction of yield and increment tables.

  2. 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.

  3. Multiphysics modeling of two-phase film boiling within porous corrosion deposits

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Miaomiao, E-mail: mmjin@mit.edu; Short, Michael, E-mail: hereiam@mit.edu

    2016-07-01

    Porous corrosion deposits on nuclear fuel cladding, known as CRUD, can cause multiple operational problems in light water reactors (LWRs). CRUD can cause accelerated corrosion of the fuel cladding, increase radiation fields and hence greater exposure risk to plant workers once activated, and induce a downward axial power shift causing an imbalance in core power distribution. In order to facilitate a better understanding of CRUD's effects, such as localized high cladding surface temperatures related to accelerated corrosion rates, we describe an improved, fully-coupled, multiphysics model to simulate heat transfer, chemical reactions and transport, and two-phase fluid flow within these deposits. Our new model features a reformed assumption of 2D, two-phase film boiling within the CRUD, correcting earlier models' assumptions of single-phase coolant flow with wick boiling under high heat fluxes. This model helps to better explain observed experimental values of the effective CRUD thermal conductivity. Finally, we propose a more complete set of boiling regimes, or a more detailed mechanism, to explain recent CRUD deposition experiments by suggesting the new concept of double dryout specifically in thick porous media with boiling chimneys. - Highlights: • A two-phase model of CRUD's effects on fuel cladding is developed and improved. • This model eliminates the formerly erroneous assumption of wick boiling. • Higher fuel cladding temperatures are predicted when accounting for two-phase flow. • Double-peaks in thermal conductivity vs. heat flux in experiments are explained. • A “double dryout” mechanism in CRUD is proposed based on the model and experiments.

  4. Three Software Tools for Viewing Sectional Planes, Volume Models, and Surface Models of a Cadaver Hand.

    Science.gov (United States)

    Chung, Beom Sun; Chung, Min Suk; Shin, Byeong Seok; Kwon, Koojoo

    2018-02-19

    The hand anatomy, including the complicated hand muscles, can be grasped by using computer-assisted learning tools with high quality two-dimensional images and three-dimensional models. The purpose of this study was to present up-to-date software tools that promote learning of stereoscopic morphology of the hand. On the basis of horizontal sectioned images and outlined images of a male cadaver, vertical planes, volume models, and surface models were elaborated. Software to browse pairs of the sectioned and outlined images in orthogonal planes and software to peel and rotate the volume models, as well as a portable document format (PDF) file to select and rotate the surface models, were produced. All of the software tools were downloadable free of charge and usable off-line. The three types of tools for viewing multiple aspects of the hand could be adequately employed according to individual needs. These new tools involving the realistic images of a cadaver and the diverse functions are expected to improve comprehensive knowledge of the hand shape. © 2018 The Korean Academy of Medical Sciences.

  5. Finite element modelling of stress development during deposition of ion assisted coatings

    International Nuclear Information System (INIS)

    Ward, D.J.; Arnell, R.D.

    2002-01-01

    Ion assisted physical vapour deposited (IAPVD) films typically have a high state of residual stress. This residual stress comprises two components: a thermal stress, which forms as the system cools to room temperature; and an intrinsic stress which is caused by the processes of deposition. Much work has been published on the tribology and mechanical behaviour of surface coatings without consideration of the residual stress. It was therefore considered desirable to develop a finite element (FE) simulation to be used either as a precursor to any realistic mechanical study of the behaviour of such surface coatings, or to be used as a tool to study the effects of varying the deposition parameters. Previous experimental work has shown that the residual stress is related to deposition parameters, such as incident ion and atom fluxes and energies, and recent molecular dynamics studies have indicated that trapped inert gas species may play a major role in the mechanism for creation of the intrinsic stress. The FE simulation assumes that the processes of ion bombardment and material deposition are consecutive, but as the analysis time step tends to zero this assumption approximates the simultaneity of the processes. Suitable mathematical descriptions are employed in the bombarded region of the growing coating to simulate the macroscopic effects of the microscopic atomic collision phenomena and diffusion processes. Two finite element simulations are presented. The first is based on an analytical model, which has gained popular acceptance and this was presented in a previous year at this conference. The second builds on this to simulate wider aspects of known behaviour and is presented in this follow-up paper. The predicted trends of mean stress and its distribution are similar to those observed in published experimental work

  6. 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

  7. Evaluation of the stomatal conductance formulation in the EMEP ozone deposition model for Picea abies

    Science.gov (United States)

    Wieser, G.; Emberson, L. D.

    It is widely acknowledged that the possible impacts of ozone on forest trees are more closely related to ozone flux through the stomata than to external ozone exposure. However, the application of the flux approach on a European scale requires the availability of appropriate models, such as the European Monitoring and Evaluation Programme (EMEP) ozone deposition model, for estimating ozone flux and cumulative ozone uptake. Within this model stomatal conductance is the key variable, since it determines the amount of ozone absorbed by the leaves. This paper describes the suitability of the existing EMEP ozone deposition model parameterisation and formulation to represent stomatal behaviour determined from field measurements on adult Norway spruce ( Picea abies (L.) Karst.) trees in the Central European Alps. Parameters affecting maximum stomatal conductance (e.g. seasonal phenology, needle position, needle age, nutrient deficiency and ozone itself) and stomatal response functions to temperature, irradiance, vapour pressure deficit, and soil water content are investigated. Finally, current limitations and possible alterations of the EMEP model will be discussed with respect to spatial scales of available input data for future flux modelling.

  8. 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.

  9. Climatological variability in modeling of long-term regional transport and deposition of air pollutants

    International Nuclear Information System (INIS)

    Shannon, J.D.

    1984-01-01

    In a growing number of emission policy analyses, regulatory proceedings, and cost/benefit assessments, numerical models of long-range transport and deposition of air pollutants have been exercised to estimate source-receptor (S-R) relationships--for the particular meteorological conditions input to the model. The representativeness of the meteorological conditions, or the variability of the model estimates with climatological input from different years or corresponding seasons from different years, is seldom evaluated. Here, two full years (1980 and 1981) of meteorological data, as well as data from January and July of 1978, are used in the Advanced Statistical Trajectory Regional Air Pollution (ASTRAP) model (Shannon, 1981), one of the eight Memorandum of Intent (MOI) models, to estimate deposition for the S-R matrix combination of eleven source regions and nine receptors used in the MOI reports. (S-R matrices of dimensions 40 by 9 were also examined in the MOI reports.) Improvements in the ASTRAP model and in the emission inventory since the earlier work require recalculation of the two-month 1978 simulation in order for the comparison to isolate the effect of meteorological variability. The source regions are listed, and the receptor regions are provide. For completeness, an additional source region, the western states and provinces, has been added, as well as a total for the 48 contiguous states and 10 provinces. 4 references, 9 tables

  10. 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 while the relatively low temperatures preclude high Cu contents. Densities of such metalliferous brines result in bottom-hugging fluids that collect in shallow saucer-shaped depressions (collector basins). Lateral metal zoning in several deposits reveals the direction from which the brines came. Relative densities of the ore-forming fluid and sediment determine whether the ore-forming fluid stabilizes on top

  11. Geological 3-D modelling and resources estimation of the Budenovskoye uranium deposit (Kazakhstan)

    International Nuclear Information System (INIS)

    Boytsov, A.; Heyns, M.; Seredkin, M.

    2014-01-01

    The Budenovskoye deposit is the biggest sandstone-hosted, roll front type uranium deposit in Kazakhstan and in the world. Uranium mineralization occurs in the unconsolidated lacustrine-alluvial sediments of Late Cretaceous Mynkuduk and Inkuduk horizons. The Budenovskoye deposit was split into four areas for development with the present Karatau ISL Mine operating No. 2 area and Akbastau ISL Mine Nos. 1, 3 and 4 areas. Mines are owned by Kazatomprom and Uranium One in equal shares. CSA Global was retained by Uranium One to update in accordance with NI 43-101 the Mineral Resource estimates for the Karatau and Akbastau Mines. The modelling Reports shows a significant increase in total uranium resources tonnage at both mines when compared to the March 2012 NI 43-101 resource estimate: at Karartau measured and indicated resources increased by 586% while at Akbastau by 286%. It has also added a 55,766 tonnes U to the Karatau Inferred Mineral Resource category.The new estimates result from the application of 3-D modelling techniques to the extensive database of drilling information, new exploration activities.

  12. TSUNAMI DEPOSITS AT QUEEN’S BEACH, OAHU, HAWAII – INITIALRESULTS AND WAVE MODELING

    Directory of Open Access Journals (Sweden)

    Dr. Barbara Keating

    2004-01-01

    Full Text Available Photographs taken immediately after the 1946 Aleutian Tsunami inundated Queen’s Beach, southeastern Oahu, show the major highway around the island was inundated and the road bed was destroyed. That road bed remains visible today, in an undeveloped coastline that shows like change in sedimentary deposits between 1946 and today (based on photographic evidence. Tsunami catalog records however indicate that the beach was repeatedly inundated by tsunami in 1946, 1952, 1957, and 1960. Tsunami runup was reported to have reached between 3 and 11 m elevation. Eyewitness accounts however indicate inundations of up to 20 m in Kealakipapa Valley (Makapu’u Lookout during 1946 and photographic evidence indicated inundation reached 9 m in 1957. The inundation of Kealakipapa Valley has been successfully modeled using a 10-m tsunami wave model.A comparison of the modern beach deposits to those near the remains of the destroyed highway demonstrate that the sedimentary deposits within the two areas have very different rock characteristics. We conclude the modern beach is dominated by the rounding of rocks (mostly coral by wave activity. However, in the area that has experienced prior tsunami inundations, the rocks are characterized by fracturing and a high component of basaltic material. We conclude the area near the destroyed highway reflects past tsunami inundations combined with inevitable anthropogenic alteration.

  13. The model of atmospheric diffusion and deposition adopted for the German reactor risk study (phase A)

    International Nuclear Information System (INIS)

    Huebschmann, W.G.; Vogt, S.

    1980-01-01

    The consequence model of the German reactor risk study comprises the release of radioactivity and thermal energy from the containment, the atmospheric diffusion, and the deposition of activity on the ground, the calculation of dose equivalents induced via the main exposure pathways, and the calculation of early and late health effects to the population, taking into account emergency actions for the protection of the public. The following exposure pathways are included in the model: external irradiation from the passing cloud and from the activity deposited on the ground, inhalation of the cloud activity and of resuspended material, and ingestion of contaminated food. Account is taken of the following effects: building wake, plume rise to thermal energy release, dynamic change of diffusion parameters, and plume depletion due to radioactive decay, dry and wet deposition. The calculations are performed for 115 weather sequences with starting times evenly distributed over one year. It is shown that such a choice of weather sequences reflects the total variety of meteorological situations, including precipitation, in a statistically adequate way. The area of the Federal Republic of Germany is divided into four meteorological site-regions, each with typical meteorological characteristics. Each power reactor site is assigned to one of the meteorological site-regions

  14. FALL3D: A Computational Model for Trans-port and Deposition of Volcanic Ash

    OpenAIRE

    Folch, A.; Costa, A.; Macedonio, G.

    2008-01-01

    FALL3D is a 3-D time-dependent Eulerian model for the transport and deposition of 8 volcanic ash. The model solves the advection-diffusion-sedimentation (ADS) equa- 9 tion on a structured terrain-following grid using a second-order Finite Differences 10 (FD) explicit scheme. Different parameterizations for the eddy diffusivity tensor 11 and for the particle terminal settling velocities can be used. The code, written 12 in FORTRAN 90, is available in both serial and parallel ver...

  15. Model of depositing layer on cylindrical surface produced by induction-assisted laser cladding process

    Directory of Open Access Journals (Sweden)

    Kotlan Václav

    2017-12-01

    Full Text Available A model of hybrid cladding on a cylindrical surface is built and numerically solved. Heating of both substrate and the powder material to be deposited on its surface is realized by laser beam and preheating inductor. The task represents a hard-coupled electromagnetic-thermal problem with time-varying geometry. Two specific algorithms are developed to incorporate this effect into the model, driven by local distribution of temperature and its gradients. The algorithms are implemented into the COMSOL Multiphysics 5.2 code that is used for numerical computations of the task. The methodology is illustrated with a typical example whose results are discussed.

  16. Modeling Non-Fickian Transport and Hyperexponential Deposition for Deep Bed Filtration

    DEFF Research Database (Denmark)

    Yuan, Hao; Shapiro, Alexander

    2010-01-01

    An integral model of the deep bed filtration process has been developed. It incorporates pore and particle size distributions, as well as the particle residence time distribution in the framework of the continuous time random walk theory. Numerical modeling is carried out to study the factors...... influencing breakthrough curves and deposition profiles for the deep bed filtration systems. Results are compared with a large set of experimental observations. Our findings show that highly dispersed breakthrough curves, e.g. those with early arrivals and large ending tails, correspond to large dispersion...

  17. Metallogenic characteristics, model and exploration prospect for the paleo-interlayer-oxidation type sandstone-hosted uranium deposits in China

    International Nuclear Information System (INIS)

    Huang Jingbai; Li Shengxiang

    2007-01-01

    In this paper, the paleo-interlayer-oxidation type sandstone-hosted uranium deposits occurred in the Meso-Cenozoic continental basins in China are divided into 3 subtype, they are stratum over lapping buried subtype, structure-uplifting destroy subtype and faulted-folding conserved subtype. The metallogenic characteristics, metallogenic model and exploration prospect for these 3 subtypes uranium deposits are discussed. It is proposed that the paleo-interlayer-oxidation type sandstone-hosted uranium deposits, besides the recent interlayer oxidation type sandstone-hosted uranium deposits, are of great prospecting potential in the Meso-Cenozoic continental basins in China. Therefore, the metallogenic theory of these types uranium deposits should be conscientiously summarized and replenished continuously so as to propel forward the exploration of the sandstone-hosted uranium deposits in China. (authors)

  18. Sediment depositions upstream of open check dams: new elements from small scale models

    Science.gov (United States)

    Piton, Guillaume; Le Guern, Jules; Carbonari, Costanza; Recking, Alain

    2015-04-01

    numbers that the flows tend to adopt? New small scale model experiments have been undertaken focusing on depositions processes and their related hydraulics. Accurate photogrammetric measurements allowed us to better describe the deposition processes3. Large Scale Particle Image Velocimetry (LS-PIV) was performed to determine surface velocity fields in highly active channels with low grain submersion4. We will present preliminary results of our experiments showing the new elements we observed in massive deposit dynamics. REFERENCES 1.Armanini, A., Dellagiacoma, F. & Ferrari, L. From the check dam to the development of functional check dams. Fluvial Hydraulics of Mountain Regions 37, 331-344 (1991). 2.Piton, G. & Recking, A. Design of sediment traps with open check dams: a review, part I: hydraulic and deposition processes. (Accepted by the) Journal of Hydraulic Engineering 1-23 (2015). 3.Le Guern, J. Ms Thesis: Modélisation physique des plages de depot : analyse de la dynamique de remplissage.(2014) . 4.Carbonari, C. Ms Thesis: Small scale experiments of deposition processes occuring in sediment traps, LS-PIV measurments and geomorphological descriptions. (in preparation).

  19. Mathematical Modelling of Waveguiding Techniques and Electron Transport. Volume 1.

    Science.gov (United States)

    1984-01-01

    II& 100 ,,.,,hi , ""%’. "-.. v -.. , ., - , , .. . . . . . .. .. . . . . .. w ,, lit ( Hit -~~ ~ (i7(2J- LKI-r~p T (4\\ 01I10T J~n Ks~ (EL 1011 -A...at the end of each output time step. The difficulty here is that the last working time step is then simply what is required to hit the output time... Tabata (2 2 ) curve fit algorithm. The comparison of the energy deposition profiles for the 1.0 MeV case is given in Table 4. More complete tables are

  20. An Optimal Investment Strategy and Multiperiod Deposit Insurance Pricing Model for Commercial Banks

    Directory of Open Access Journals (Sweden)

    Grant E. Muller

    2018-01-01

    Full Text Available We employ the method of stochastic optimal control to derive the optimal investment strategy for maximizing an expected exponential utility of a commercial bank’s capital at some future date T>0. In addition, we derive a multiperiod deposit insurance (DI pricing model that incorporates the explicit solution of the optimal control problem and an asset value reset rule comparable to the typical practice of insolvency resolution by insuring agencies. By way of numerical simulations, we study the effects of changes in the DI coverage horizon, the risk associated with the asset portfolio of the bank, and the bank’s initial leverage level (deposit-to-asset ratio on the DI premium while the optimal investment strategy is followed.

  1. Application of Fused Deposition Modelling (FDM) Method of 3D Printing in Drug Delivery.

    Science.gov (United States)

    Long, Jingjunjiao; Gholizadeh, Hamideh; Lu, Jun; Bunt, Craig; Seyfoddin, Ali

    2017-01-01

    Three-dimensional (3D) printing is an emerging manufacturing technology for biomedical and pharmaceutical applications. Fused deposition modelling (FDM) is a low cost extrusion-based 3D printing technique that can deposit materials layer-by-layer to create solid geometries. This review article aims to provide an overview of FDM based 3D printing application in developing new drug delivery systems. The principle methodology, suitable polymers and important parameters in FDM technology and its applications in fabrication of personalised tablets and drug delivery devices are discussed in this review. FDM based 3D printing is a novel and versatile manufacturing technique for creating customised drug delivery devices that contain accurate dose of medicine( s) and provide controlled drug released profiles. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  2. 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...... 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......Soil degradation and environmental impacts due to water erosion are a growing concern globally. Large parts of Denmark are covered by gently rolling moraine landscape with moderately to locally highly erodible soils where water erosion causes off-site problems in the form of eutrophication of water...

  3. Transportation Sector Model of the National Energy Modeling System. Volume 2 -- Appendices: Part 2

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-01-01

    The attachments contained within this appendix provide additional details about the model development and estimation process which do not easily lend themselves to incorporation in the main body of the model documentation report. The information provided in these attachments is not integral to the understanding of the model`s operation, but provides the reader with opportunity to gain a deeper understanding of some of the model`s underlying assumptions. There will be a slight degree of replication of materials found elsewhere in the documentation, made unavoidable by the dictates of internal consistency. Each attachment is associated with a specific component of the transportation model; the presentation follows the same sequence of modules employed in Volume 1. The following attachments are contained in Appendix F: Fuel Economy Model (FEM)--provides a discussion of the FEM vehicle demand and performance by size class models; Alternative Fuel Vehicle (AFV) Model--describes data input sources and extrapolation methodologies; Light-Duty Vehicle (LDV) Stock Model--discusses the fuel economy gap estimation methodology; Light Duty Vehicle Fleet Model--presents the data development for business, utility, and government fleet vehicles; Light Commercial Truck Model--describes the stratification methodology and data sources employed in estimating the stock and performance of LCT`s; Air Travel Demand Model--presents the derivation of the demographic index, used to modify estimates of personal travel demand; and Airborne Emissions Model--describes the derivation of emissions factors used to associate transportation measures to levels of airborne emissions of several pollutants.

  4. Fused deposition modeling (FDM) fabricated part behavior under tensile stress, thermal cycling, and fluid pressure

    Science.gov (United States)

    Hossain, Mohammad Shojib

    Material extrusion based additive manufacturing (AM) technology, such as fused deposition modeling (FDM), is gaining popularity with the numerous 3D printers available worldwide. FDM technology is advancing from exclusively prototype construction to achieving production-grade quality. Today, FDM-fabricated parts are widely used in the aerospace industries, biomedical applications, and other industries that may require custom fabricated, low volume parts. These applications are and were possible because of the different production grade material options (e.g., acrylonitrile butadiene styrene (ABS), polycarbonate (PC), polyphenylsulfone (PPSF), etc.) available to use in FDM systems. Recent researchers are exploring other material options including polycaprolactone (PCL), polymethylmethacrylate (PMMA), composites containing ceramic, glass and metal fillers, and even metals which depict the diversified materials and possibility of new material options using FDM technology. The understanding of the behavior and mechanical properties of the finished FDM-fabricated parts is of utmost importance in the advancement of this technology. The processing parameters, e.g., build orientation, raster width (RW), contour width (CW), raster angle (RA), and raster to raster air gap (RRAG) are important factors in determining the mechanical properties of FDM fabricated parts. The work presented here focused on the mechanical properties improvement by modifying those build parameters. The main concentration is on how modifying those parameters can improve ultimate tensile stress (UTS), Young's modulus, and tensile strain of the final product. In this research, PC parts were fabricated using three build methods: 1) default method, 2) Insight revision method, and 3) visual feedback method. By modifying build parameters, the highest average UTS obtained for PC was 63.96 MPa which was 7% higher than that of 59.73 MPa obtained using the default build parameters. The parameter modification

  5. On the non-equilibrium phase transition in evaporation–deposition models

    International Nuclear Information System (INIS)

    Connaughton, Colm; Zaboronski, Oleg; Rajesh, R

    2010-01-01

    We study a system of diffusing–aggregating particles with deposition and evaporation of monomers. By combining theoretical and numerical methods, we establish a clearer understanding of the non-equilibrium phase transition known to occur in such systems. The transition is between a growing phase in which the total mass increases for all time and a non-growing phase in which the total mass is bounded. In addition to deriving rigorous bounds on the position of the transition point, we show that the growing phase is in the same universality class as diffusion–aggregation models with deposition but no evaporation. In this regime, the flux of mass in mass space becomes asymptotically constant (as a function of mass) at large times. The magnitude of this flux depends on the evaporation rate but the fact that it is asymptotically constant does not. The associated constant flux relation exactly determines the scaling of the two-point mass correlation function with mass in all dimensions while higher order mass correlation functions exhibit nonlinear multi-scaling in dimension less than two. If the deposition rate is below some critical value, a different stationary state is reached at large times characterized by a global balance between evaporation and deposition with a scale-by-scale balance between the mass fluxes due to aggregation and evaporation. Both the mass distribution and the flux decay exponentially in this regime. Finally, we develop a scaling theory of the model near the critical point, which yields non-trivial scaling laws for the critical two-point mass correlation function with mass. These results are well supported by numerical measurements

  6. Variation in Measurements of Transtibial Stump Model Volume A Comparison of Five Methods

    NARCIS (Netherlands)

    Bolt, A.; de Boer-Wilzing, V. G.; Geertzen, J. H. B.; Emmelot, C. H.; Baars, E. C. T.; Dijkstra, P. U.

    Objective: To determine the right moment for fitting the first prosthesis, it is necessary to know when the volume of the stump has stabilized. The aim of this study is to analyze variation in measurements of transtibial stump model volumes using the water immersion method, the Design TT system, the

  7. 1987 Oak Ridge model conference: Proceedings: Volume 3, Health and safety

    International Nuclear Information System (INIS)

    1987-01-01

    See the abstract for Volume I for general information on the conference. Topics discussed in Volume III include the use of models in handling hazardous materials, communication at waste sites, asbestos, regulatory decisions, emergency planning, training programs, occupational hazards, and protection of subcontractors

  8. Estimating tree bole volume using artificial neural network models for four species in Turkey.

    Science.gov (United States)

    Ozçelik, Ramazan; Diamantopoulou, Maria J; Brooks, John R; Wiant, Harry V

    2010-01-01

    Tree bole volumes of 89 Scots pine (Pinus sylvestris L.), 96 Brutian pine (Pinus brutia Ten.), 107 Cilicica fir (Abies cilicica Carr.) and 67 Cedar of Lebanon (Cedrus libani A. Rich.) trees were estimated using Artificial Neural Network (ANN) models. Neural networks offer a number of advantages including the ability to implicitly detect complex nonlinear relationships between input and output variables, which is very helpful in tree volume modeling. Two different neural network architectures were used and produced the Back propagation (BPANN) and the Cascade Correlation (CCANN) Artificial Neural Network models. In addition, tree bole volume estimates were compared to other established tree bole volume estimation techniques including the centroid method, taper equations, and existing standard volume tables. An overview of the features of ANNs and traditional methods is presented and the advantages and limitations of each one of them are discussed. For validation purposes, actual volumes were determined by aggregating the volumes of measured short sections (average 1 meter) of the tree bole using Smalian's formula. The results reported in this research suggest that the selected cascade correlation artificial neural network (CCANN) models are reliable for estimating the tree bole volume of the four examined tree species since they gave unbiased results and were superior to almost all methods in terms of error (%) expressed as the mean of the percentage errors. 2009 Elsevier Ltd. All rights reserved.

  9. Design and Analysis of Fused Deposition Modeling 3D Printer Nozzle for Color Mixing

    Directory of Open Access Journals (Sweden)

    Shanling Han

    2017-01-01

    Full Text Available Fused deposition modeling (FDM has been one of the most widely used rapid prototyping (RP technologies leading to the increase in market attention. Obviously it is desirable to print 3D objects; however, existing FDM printers are restricted to printing only monochrome objects because of the entry-level nozzle structure, and literature on the topic is also sparse. In this paper, the CAD model of the nozzle is established first by UG (Unigraphics NX software to show the structure of fused deposition modeling 3D printer nozzle for color mixing. Second, the flow channel model of the nozzle is extracted and simplified. Then, the CAD and finite element model are established by UG and ICEM CFD software, respectively, to prepare for the simulation. The flow field is simulated by Fluent software. The nozzle’s suitable temperature at different extrusion speeds is obtained, and the reason for the blockage at the intersection of the heating block is revealed. Finally, test verification of the nozzle is performed, which can produce mixed-color artifacts stably.

  10. Literature review of models for estimating soil erosion and deposition from wind stresses on uranium-mill-tailings covers

    Energy Technology Data Exchange (ETDEWEB)

    Bander, T.J.

    1982-11-01

    Pacific Northwest Laboratory (PNL) is investigating the use of a rock armoring blanket (riprap) to mitigate wind and water erosion of an earthen radon-suppression cover applied to uranium-mill tailings. The mechanics of wind erosion, as well as of soil deposition, are discussed in this report. Several wind erosion models are reviewed to determine if they can be used to estimate the erosion of soil from a mill-tailings cover. One model, developed by W.S. Chepil, contains the most-important factors that describe variables that influence wind erosion. Particular features of other models are also discussed, as well as the application of Chepil's model to a particular tailings pile. For this particular tailings pile, the estimated erosion was almost one inch per year for an unprotected tailings soil surface. Wide variability in the deposition velocity and lack of adequate deposition models preclude reliable estimates of the rate at which airborne particles are deposited.

  11. Literature review of models for estimating soil erosion and deposition from wind stresses on uranium-mill-tailings covers

    International Nuclear Information System (INIS)

    Bander, T.J.

    1982-11-01

    Pacific Northwest Laboratory (PNL) is investigating the use of a rock armoring blanket (riprap) to mitigate wind and water erosion of an earthen radon-suppression cover applied to uranium-mill tailings. The mechanics of wind erosion, as well as of soil deposition, are discussed in this report. Several wind erosion models are reviewed to determine if they can be used to estimate the erosion of soil from a mill-tailings cover. One model, developed by W.S. Chepil, contains the most-important factors that describe variables that influence wind erosion. Particular features of other models are also discussed, as well as the application of Chepil's model to a particular tailings pile. For this particular tailings pile, the estimated erosion was almost one inch per year for an unprotected tailings soil surface. Wide variability in the deposition velocity and lack of adequate deposition models preclude reliable estimates of the rate at which airborne particles are deposited

  12. Numerical modeling of carrier gas flow in atomic layer deposition vacuum reactor: A comparative study of lattice Boltzmann models

    International Nuclear Information System (INIS)

    Pan, Dongqing; Chien Jen, Tien; Li, Tao; Yuan, Chris

    2014-01-01

    This paper characterizes the carrier gas flow in the atomic layer deposition (ALD) vacuum reactor by introducing Lattice Boltzmann Method (LBM) to the ALD simulation through a comparative study of two LBM models. Numerical models of gas flow are constructed and implemented in two-dimensional geometry based on lattice Bhatnagar–Gross–Krook (LBGK)-D2Q9 model and two-relaxation-time (TRT) model. Both incompressible and compressible scenarios are simulated and the two models are compared in the aspects of flow features, stability, and efficiency. Our simulation outcome reveals that, for our specific ALD vacuum reactor, TRT model generates better steady laminar flow features all over the domain with better stability and reliability than LBGK-D2Q9 model especially when considering the compressible effects of the gas flow. The LBM-TRT is verified indirectly by comparing the numerical result with conventional continuum-based computational fluid dynamics solvers, and it shows very good agreement with these conventional methods. The velocity field of carrier gas flow through ALD vacuum reactor was characterized by LBM-TRT model finally. The flow in ALD is in a laminar steady state with velocity concentrated at the corners and around the wafer. The effects of flow fields on precursor distributions, surface absorptions, and surface reactions are discussed in detail. Steady and evenly distributed velocity field contribute to higher precursor concentration near the wafer and relatively lower particle velocities help to achieve better surface adsorption and deposition. The ALD reactor geometry needs to be considered carefully if a steady and laminar flow field around the wafer and better surface deposition are desired

  13. Numerical modeling of carrier gas flow in atomic layer deposition vacuum reactor: A comparative study of lattice Boltzmann models

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Dongqing; Chien Jen, Tien [Department of Mechanical Engineering, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201 (United States); Li, Tao [School of Mechanical Engineering, Dalian University of Technology, Dalian 116024 (China); Yuan, Chris, E-mail: cyuan@uwm.edu [Department of Mechanical Engineering, University of Wisconsin-Milwaukee, 3200 North Cramer Street, Milwaukee, Wisconsin 53211 (United States)

    2014-01-15

    This paper characterizes the carrier gas flow in the atomic layer deposition (ALD) vacuum reactor by introducing Lattice Boltzmann Method (LBM) to the ALD simulation through a comparative study of two LBM models. Numerical models of gas flow are constructed and implemented in two-dimensional geometry based on lattice Bhatnagar–Gross–Krook (LBGK)-D2Q9 model and two-relaxation-time (TRT) model. Both incompressible and compressible scenarios are simulated and the two models are compared in the aspects of flow features, stability, and efficiency. Our simulation outcome reveals that, for our specific ALD vacuum reactor, TRT model generates better steady laminar flow features all over the domain with better stability and reliability than LBGK-D2Q9 model especially when considering the compressible effects of the gas flow. The LBM-TRT is verified indirectly by comparing the numerical result with conventional continuum-based computational fluid dynamics solvers, and it shows very good agreement with these conventional methods. The velocity field of carrier gas flow through ALD vacuum reactor was characterized by LBM-TRT model finally. The flow in ALD is in a laminar steady state with velocity concentrated at the corners and around the wafer. The effects of flow fields on precursor distributions, surface absorptions, and surface reactions are discussed in detail. Steady and evenly distributed velocity field contribute to higher precursor concentration near the wafer and relatively lower particle velocities help to achieve better surface adsorption and deposition. The ALD reactor geometry needs to be considered carefully if a steady and laminar flow field around the wafer and better surface deposition are desired.

  14. Assessment of nasal spray deposition pattern in a silicone human nose model using a color-based method.

    Science.gov (United States)

    Kundoor, Vipra; Dalby, Richard N

    2010-01-01

    To develop a simple and inexpensive method to visualize and quantify droplet deposition patterns. Deposition pattern was determined by uniformly coating the nose model with Sar-Gel (a paste that changes from white to purple on contact with water) and subsequently discharging sprays into the nose model. The color change was captured using a digital camera and analyzed using Adobe Photoshop. Several tests were conducted to validate the method. Deposition patterns of different nasal sprays (Ayr, Afrin, and Zicam) and different nasal drug delivery devices (Afrin nasal spray and PARI Sinustar nasal nebulizer) were compared. We also used the method to evaluate the effect of inhaled flow rate on nasal spray deposition. There was a significant difference in the deposition area for Ayr, Afrin, and Zicam. The deposition areas of Afrin nasal spray and PARI Sinustar nasal nebulizer (2 min and 5 min) were significantly different. Inhaled flow rate did not have a significant effect on the deposition pattern. Lower viscosity formulations (Ayr, Afrin) provided greater coverage than the higher viscosity formulation (Zicam). The nebulizer covered a greater surface area than the spray pump we evaluated. Aerosol deposition in the nose model was not affected by air flow conditions.

  15. Modelling of marine base cation emissions, concentrations and deposition in the UK

    Directory of Open Access Journals (Sweden)

    M. Werner

    2011-02-01

    Full Text Available Base cations exert a large impact on various geochemical and geophysical processes both in the atmosphere and at the Earth surface. One of the essential roles of these compounds is impact on surface pH causing an increase in alkalinity and neutralizing the effects of acidity generated by sulphur and nitrogen deposition. During recent years anthropogenic emissions of base cations in the UK have decreased substantially, by about 70%, 78%, 75% and 48% for Na+, Mg2+, Ca2+ and K+, respectively, over the period 1990–2006. For the island regions, such as the UK, the main source of base cation particles is the aerosol produced from the sea surface. Here, the sea salt aerosol (SSA emissions are calculated with parameterisations proposed by Mårtensson et al. (2003 for ultra fine particles, Monahan et al. (1986 for fine particles and Smith and Harisson (1998 for coarse particles continuously with a 0.1 μm size step using WRF-modelled wind speed data at a 5 km × 5 km grid square resolution with a 3 h time step for two selected years 2003 and 2006. SSA production has been converted into base cation emissions, with the assumption that the chemical composition of the particle emitted from the sea surface is equal to the chemical composition of sea water, and used as input data in the Fine Resolution Atmospheric Multi-pollutant Exchange Model (FRAME. FRAME model annual mean concentrations and total wet deposition at a 5 km × 5 km grid resolution, are compared with concentrations in air and wet deposition from the National Monitoring Network and measurements based estimates of UK deposition budget. The correlation coefficient for wet deposition achieves high values (R = 0.8 for Na+ and Mg2+, whereas for Ca2+ the correlation is poor (R < 0.3. Base cation concentrations are also represented well, with some overestimations on the west coast and underestimations in the

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

    Science.gov (United States)

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

    2011-04-01

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

  17. Estuarine Sediment Deposition during Wetland Restoration: A GIS and Remote Sensing Modeling Approach

    Science.gov (United States)

    Newcomer, Michelle; Kuss, Amber; Kentron, Tyler; Remar, Alex; Choksi, Vivek; Skiles, J. W.

    2011-01-01

    Restoration of the industrial salt flats in the San Francisco Bay, California is an ongoing wetland rehabilitation project. Remote sensing maps of suspended sediment concentration, and other GIS predictor variables were used to model sediment deposition within these recently restored ponds. Suspended sediment concentrations were calibrated to reflectance values from Landsat TM 5 and ASTER using three statistical techniques -- linear regression, multivariate regression, and an Artificial Neural Network (ANN), to map suspended sediment concentrations. Multivariate and ANN regressions using ASTER proved to be the most accurate methods, yielding r2 values of 0.88 and 0.87, respectively. Predictor variables such as sediment grain size and tidal frequency were used in the Marsh Sedimentation (MARSED) model for predicting deposition rates for three years. MARSED results for a fully restored pond show a root mean square deviation (RMSD) of 66.8 mm (<1) between modeled and field observations. This model was further applied to a pond breached in November 2010 and indicated that the recently breached pond will reach equilibrium levels after 60 months of tidal inundation.

  18. Uncertainty and Sensitivity Analysis of Filtration Models for Non-Fickian transport and Hyperexponential deposition

    DEFF Research Database (Denmark)

    Yuan, Hao; Sin, Gürkan

    2011-01-01

    Uncertainty and sensitivity analyses are carried out to investigate the predictive accuracy of the filtration models for describing non-Fickian transport and hyperexponential deposition. Five different modeling approaches, involving the elliptic equation with different types of distributed...... filtration coefficients and the CTRW equation expressed in Laplace space, are selected to simulate eight experiments. These experiments involve both porous media and colloid-medium interactions of different heterogeneity degrees. The uncertainty of elliptic equation predictions with distributed filtration...... coefficients is larger than that with a single filtration coefficient. The uncertainties of model predictions from the elliptic equation and CTRW equation in Laplace space are minimal for solute transport. Higher uncertainties of parameter estimation and model outputs are observed in the cases with the porous...

  19. Review of air quality modeling techniques. Volume 8

    International Nuclear Information System (INIS)

    Rosen, L.C.

    1977-01-01

    Air transport and diffusion models which are applicable to the assessment of the environmental effects of nuclear, geothermal, and fossil-fuel electric generation are reviewed. The general classification of models and model inputs are discussed. A detailed examination of the statistical, Gaussian plume, Gaussian puff, one-box and species-conservation-of-mass models is given. Representative models are discussed with attention given to the assumptions, input data requirement, advantages, disadvantages and applicability of each

  20. NATO Reference Mobility Model. Edition I. Users Guide. Volume I

    Science.gov (United States)

    1979-10-01

    C TOTAL ERAKING FCRCE - SCIL /SLOPE/VEHICLE C --- ----.----------- C 275 R-2WJ58# VCLUIJE I PAGE A-103 APPEND-IX A - LISTING CF O.CFAt’ NRtPM C 1...sGCW vN1RAV ,SFTYPC 9TBF I- c r-------------------------~e e C tPAXIMUP BRAKING FCRCE * SCIL /SL OP E/V ENICLE/ DRIVER C --------------------- C C 1. VAR...CONTINUE GO TC 2160 ,ýObO IFl IST ,NE, 21 GC TG 2110i 317 R-20358, VOLUME I PAGE A-145 APPENDIX A - LISTING CF FRGG/iAM NAMM C 8. COARSE GRAINED SCIL IF

  1. Imaging Quaternary glacial deposits and basement topography using the transient electromagnetic method for modeling aquifer environments

    Science.gov (United States)

    Simard, Patrick Tremblay; Chesnaux, Romain; Rouleau, Alain; Daigneault, Réal; Cousineau, Pierre A.; Roy, Denis W.; Lambert, Mélanie; Poirier, Brigitte; Poignant-Molina, Léo

    2015-08-01

    Aquifer formations along the northern shore of the Saint-Lawrence River in Quebec (Canada) mainly consist of glacial and coastal deposits of variable thickness overlying Precambrian bedrock. These deposits are important because they provide the main water supply for many communities. As part of a continuing project aimed at developing an inventory of the groundwater resources in the Charlevoix and Haute-Côte-Nord (CHCN) regions of the province of Quebec in Canada, the central loop transient electromagnetic (TEM) method was used to map the principal hydrogeological environments in these regions. One-dimensional smooth inversion models of the TEM soundings have been used to construct two-dimensional electrical resistivity sections, which provided images for hydrogeological validation. Electrical contour lines of aquifer environments were compared against available well logs and Quaternary surface maps in order to interpret TEM soundings. A calibration table was achieved to represent common deposits and basements. The calibration table was then exported throughout the CHCN region. This paper presents three case studies; one in the Forestville site, another in the Les Escoumins site and the other in the Saint-Urbain site. These sites were selected as targets for geophysical surveys because of the general lack of local direct hydrogeological data related to them.

  2. Macrophage Depletion Attenuates Extracellular Matrix Deposition and Ductular Reaction in a Mouse Model of Chronic Cholangiopathies

    Science.gov (United States)

    Syn, Wing-Kin; Lagaisse, Kimberly; van Hul, Noemi; Heindryckx, Femke; Sowa, Jan-Peter; Peeters, Liesbeth; Van Vlierberghe, Hans; Leclercq, Isabelle A.; Canbay, Ali

    2016-01-01

    Chronic cholangiopathies, such as primary and secondary sclerosing cholangitis, are progressive disease entities, associated with periportal accumulation of inflammatory cells, encompassing monocytes and macrophages, peribiliary extracellular matrix (ECM) deposition and ductular reaction (DR). This study aimed to elucidate the relevance of macrophages in the progression of chronic cholangiopathies through macrophage depletion in a 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) mouse model. One group of mice received a single i.p. injection of Clodronate encapsulated liposomes (CLOLipo) at day 7 of a 14 day DDC treatment, while control animals were co-treated with PBSLipo instead. Mice were sacrificed after 7 or respectively 14 days of treatment for immunohistochemical assessment of macrophage recruitment (F4/80), ECM deposition (Sirius Red, Laminin) and DR (CK19). Macrophage depletion during a 14 day DDC treatment resulted in a significant inhibition of ECM deposition. Porto-lobular migration patterns of laminin-rich ECM and ductular structures were significantly attenuated and a progression of DR was effectively inhibited by macrophage depletion. CLOLipo co-treatment resulted in a confined DR to portal regions without amorphous cell clusters. This study suggests that therapeutic options selectively directed towards macrophages might represent a feasible treatment for chronic cholestatic liver diseases. PMID:27618307

  3. VIPRE-01. a thermal-hydraulic analysis code for reactor cores. Volume 1. Mathematical modeling

    International Nuclear Information System (INIS)

    Stewart, C.W.; Cuta, J.M.; Koontz, A.S.; Kelly, J.M.; Basehore, K.L.; George, T.L.; Rowe, D.S.

    1983-04-01

    VIPRE (Versatile Internals and Component Program for Reactors; EPRI) has been developed for nuclear power utility thermal-hydraulic analysis applications. It is designed to help evaluate nuclear reactor core safety limits including minimum departure from nucleate boiling ratio (MDNBR), critical power ratio (CPR), fuel and clad temperatures, and coolant state in normal operation and assumed accident conditions. This volume (Volume 1: Mathematical Modeling) explains the major thermal hydraulic models and supporting correlations in detail

  4. Effects of experimental nitrogen deposition on peatland carbon pools and fluxes: a modeling analysis

    Science.gov (United States)

    Wu, Y.; Blodau, C.; Moore, T. R.; Bubier, J. L.; Juutinen, S.; Larmola, T.

    2014-07-01

    Nitrogen (N) pollution of peatlands alters their carbon (C) balances, yet long-term effects and controls are poorly understood. We applied the model PEATBOG to analyze impacts of long-term nitrogen (N) fertilization on C cycling in an ombrotrophic bog. Simulations of summer gross ecosystem production (GEP), ecosystem respiration (ER) and net ecosystem exchange (NEE) were evaluated against 8 years of observations and extrapolated for 80 years to identify potential effects of N fertilization and factors influencing model behavior. The model successfully simulated moss decline and raised GEP, ER and NEE on fertilized plots. GEP was systematically overestimated in the model compared to the field data due to high tolerance of Sphagnum to N deposition in the model. Model performance regarding the 8 year response of GEP and NEE to N was improved by introducing an N content threshold shifting the response of photosynthesis capacity to N content in shrubs and graminoids from positive to negative at high N contents. Such changes also eliminated the competitive advantages of vascular species and led to resilience of mosses in the long-term. Regardless of the large changes of C fluxes over the short-term, the simulated GEP, ER and NEE after 80 years depended on whether a graminoid- or shrub-dominated system evolved. When the peatland remained shrub-Sphagnum dominated, it shifted to a C source after only 10 years of fertilization at 6.4 g N m-2 yr-1, whereas this was not the case when it became graminoid-dominated. The modeling results thus highlight the importance of ecosystem adaptation and reaction of plant functional types to N deposition, when predicting the future C balance of N-polluted cool temperate bogs.

  5. Effects of experimental nitrogen deposition on peatland carbon pools and fluxes: a modelling analysis

    Science.gov (United States)

    Wu, Y.; Blodau, C.; Moore, T. R.; Bubier, J.; Juutinen, S.; Larmola, T.

    2015-01-01

    Nitrogen (N) pollution of peatlands alters their carbon (C) balances, yet long-term effects and controls are poorly understood. We applied the model PEATBOG to explore impacts of long-term nitrogen (N) fertilization on C cycling in an ombrotrophic bog. Simulations of summer gross ecosystem production (GEP), ecosystem respiration (ER) and net ecosystem exchange (NEE) were evaluated against 8 years of observations and extrapolated for 80 years to identify potential effects of N fertilization and factors influencing model behaviour. The model successfully simulated moss decline and raised GEP, ER and NEE on fertilized plots. GEP was systematically overestimated in the model compared to the field data due to factors that can be related to differences in vegetation distribution (e.g. shrubs vs. graminoid vegetation) and to high tolerance of vascular plants to N deposition in the model. Model performance regarding the 8-year response of GEP and NEE to N input was improved by introducing an N content threshold shifting the response of photosynthetic capacity (GEPmax) to N content in shrubs and graminoids from positive to negative at high N contents. Such changes also eliminated the competitive advantages of vascular species and led to resilience of mosses in the long-term. Regardless of the large changes of C fluxes over the short-term, the simulated GEP, ER and NEE after 80 years depended on whether a graminoid- or shrub-dominated system evolved. When the peatland remained shrub-Sphagnum-dominated, it shifted to a C source after only 10 years of fertilization at 6.4 g N m-2 yr-1, whereas this was not the case when it became graminoid-dominated. The modelling results thus highlight the importance of ecosystem adaptation and reaction of plant functional types to N deposition, when predicting the future C balance of N-polluted cool temperate bogs.

  6. Evaluation of five dry particle deposition parameterizations for incorporation into atmospheric transport models

    Science.gov (United States)

    Khan, Tanvir R.; Perlinger, Judith A.

    2017-10-01

    Despite considerable effort to develop mechanistic dry particle deposition parameterizations for atmospheric transport models, current knowledge has been inadequate to propose quantitative measures of the relative performance of available parameterizations. In this study, we evaluated the performance of five dry particle deposition parameterizations developed by Zhang et al. (2001) (Z01), Petroff and Zhang (2010) (PZ10), Kouznetsov and Sofiev (2012) (KS12), Zhang and He (2014) (ZH14), and Zhang and Shao (2014) (ZS14), respectively. The evaluation was performed in three dimensions: model ability to reproduce observed deposition velocities, Vd (accuracy); the influence of imprecision in input parameter values on the modeled Vd (uncertainty); and identification of the most influential parameter(s) (sensitivity). The accuracy of the modeled Vd was evaluated using observations obtained from five land use categories (LUCs): grass, coniferous and deciduous forests, natural water, and ice/snow. To ascertain the uncertainty in modeled Vd, and quantify the influence of imprecision in key model input parameters, a Monte Carlo uncertainty analysis was performed. The Sobol' sensitivity analysis was conducted with the objective to determine the parameter ranking from the most to the least influential. Comparing the normalized mean bias factors (indicators of accuracy), we find that the ZH14 parameterization is the most accurate for all LUCs except for coniferous forest, for which it is second most accurate. From Monte Carlo simulations, the estimated mean normalized uncertainties in the modeled Vd obtained for seven particle sizes (ranging from 0.005 to 2.5 µm) for the five LUCs are 17, 12, 13, 16, and 27 % for the Z01, PZ10, KS12, ZH14, and ZS14 parameterizations, respectively. From the Sobol' sensitivity results, we suggest that the parameter rankings vary by particle size and LUC for a given parameterization. Overall, for dp = 0.001 to 1.0 µm, friction velocity was one of

  7. Evaluation of five dry particle deposition parameterizations for incorporation into atmospheric transport models

    Directory of Open Access Journals (Sweden)

    T. R. Khan

    2017-10-01

    Full Text Available Despite considerable effort to develop mechanistic dry particle deposition parameterizations for atmospheric transport models, current knowledge has been inadequate to propose quantitative measures of the relative performance of available parameterizations. In this study, we evaluated the performance of five dry particle deposition parameterizations developed by Zhang et al. (2001 (Z01, Petroff and Zhang (2010 (PZ10, Kouznetsov and Sofiev (2012 (KS12, Zhang and He (2014 (ZH14, and Zhang and Shao (2014 (ZS14, respectively. The evaluation was performed in three dimensions: model ability to reproduce observed deposition velocities, Vd (accuracy; the influence of imprecision in input parameter values on the modeled Vd (uncertainty; and identification of the most influential parameter(s (sensitivity. The accuracy of the modeled Vd was evaluated using observations obtained from five land use categories (LUCs: grass, coniferous and deciduous forests, natural water, and ice/snow. To ascertain the uncertainty in modeled Vd, and quantify the influence of imprecision in key model input parameters, a Monte Carlo uncertainty analysis was performed. The Sobol' sensitivity analysis was conducted with the objective to determine the parameter ranking from the most to the least influential. Comparing the normalized mean bias factors (indicators of accuracy, we find that the ZH14 parameterization is the most accurate for all LUCs except for coniferous forest, for which it is second most accurate. From Monte Carlo simulations, the estimated mean normalized uncertainties in the modeled Vd obtained for seven particle sizes (ranging from 0.005 to 2.5 µm for the five LUCs are 17, 12, 13, 16, and 27 % for the Z01, PZ10, KS12, ZH14, and ZS14 parameterizations, respectively. From the Sobol' sensitivity results, we suggest that the parameter rankings vary by particle size and LUC for a given parameterization. Overall, for dp  =  0.001 to 1.0

  8. Modeling of phase transformations of Ti6Al4 V during laser metal deposition

    Science.gov (United States)

    Suárez, A.; Tobar, M. J.; Yáñez, A.; Pérez, I.; Sampedro, J.; Amigó, V.; Candel, J. J.

    The low density, excellent high temperature mechanical properties and good corrosion resistance of titanium and its alloys have led to a diversified range of successful applications. As a consequence, there is a demand of increasing the capabilities of processing such alloys. The laser cladding technique allows direct metal deposition with an excellent metallurgical bond and a pore free fine grained microstructure. A nonlinear transient thermo-metallurgical model was developed to study the technique with titanium alloys to get a better understanding of the thermal and metallurgical underlying aspects. The calculated temperatures and phase transformations are compared with experimental tests.

  9. 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.

  10. Constitutive Modelling in Thermomechanical Processes, Using The Control Volume Method on Staggered Grid

    DEFF Research Database (Denmark)

    Thorborg, Jesper

    , however, is constituted by the implementation of the $J_2$ flow theory in the control volume method. To apply the control volume formulation on the process of hardening concrete viscoelastic stress-strain models has been examined in terms of various rheological models. The generalized 3D models are based...... on two different suggestions in the literature, that is compressible or incompressible behaviour of the viscos response in the dashpot element. Numerical implementation of the models has shown very good agreement with corresponding analytical solutions. The viscoelastic solid mechanical model is used...

  11. Underground Test Area Subproject Phase I Data Analysis Task. Volume VII - Tritium Transport Model Documentation Package

    Energy Technology Data Exchange (ETDEWEB)

    None

    1996-12-01

    Volume VII of the documentation for the Phase I Data Analysis Task performed in support of the current Regional Flow Model, Transport Model, and Risk Assessment for the Nevada Test Site Underground Test Area Subproject contains the tritium transport model documentation. Because of the size and complexity of the model area, a considerable quantity of data was collected and analyzed in support of the modeling efforts. The data analysis task was consequently broken into eight subtasks, and descriptions of each subtask's activities are contained in one of the eight volumes that comprise the Phase I Data Analysis Documentation.

  12. Statistical Modeling of Ultrawideband Body-Centric Wireless Channels Considering Room Volume

    Directory of Open Access Journals (Sweden)

    Miyuki Hirose

    2012-01-01

    Full Text Available This paper presents the results of a statistical modeling of onbody ultrawideband (UWB radio channels for wireless body area network (WBAN applications. Measurements were conducted in five different rooms. A measured delay profile can be divided into two domains; in the first domain (04 ns has multipath components that are dominant and dependent on room volume. The first domain was modeled with a conventional power decay law model, and the second domain with a modified Saleh-Valenzuela model considering the room volume. Realizations of the impulse responses are presented based on the composite model and compared with the measured average power delay profiles.

  13. A study of uniformity of elements deposition on glass fiber filters after collection of airborne particulate matter (PM-10), using a high-volume sampler.

    Science.gov (United States)

    Marrero, Julieta; Rebagliati, Raúl Jiménez; Gómez, Darío; Smichowski, Patricia

    2005-12-15

    A study was conducted to evaluate the homogeneity of the distribution of metals and metalloids deposited on glass fiber filters collected using a high-volume sampler equipped with a PM-10 sampling head. The airborne particulate matter (APM)-loaded glass fiber filters (with an active surface of about 500cm(2)) were weighed and then each filter was cut in five small discs of 6.5cm of diameter. Each disk was mineralized by acid-assisted microwave (MW) digestion using a mixture of nitric, perchloric and hydrofluoric acids. Analysis was performed by axial view inductively coupled plasma optical emission spectrometry (ICP OES) and the elements considered were: Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Sb, Ti and V. The validation of the procedure was performed by the analysis of the standard reference material NIST 1648, urban particulate matter. As a way of comparing the possible variability in trace elements distribution in a particular filter, the mean concentration for each element over the five positions (discs) was calculated and each element concentration was normalized to this mean value. Scatter plots of the normalized concentrations were examined for all elements and all sub-samples. We considered that an element was homogeneously distributed if its normalized concentrations in the 45 sub-samples were within +/-15% of the mean value ranging between 0.85 and 1.15. The study demonstrated that the 12 elements tested showed different distribution pattern. Aluminium, Cu and V showed the most homogeneous pattern while Cd and Ni exhibited the largest departures from the mean value in 13 out of the 45 discs analyzed. No preferential deposition was noticed in any sub-sample.

  14. Zr-ZrO sub 2 cermet solar coatings designed by modelling calculations and deposited by dc magnetron sputtering

    CERN Document Server

    Zhang Qi Chu; Lee, K D; Shen, Y G

    2003-01-01

    High solar performance Zr-ZrO sub 2 cermet solar coatings were designed using a numerical computer model and deposited experimentally. The layer thickness and Zr metal volume fraction for the Zr-ZrO sub 2 cermet solar selective coatings on a Zr or Al reflector with a surface ZrO sub 2 or Al sub 2 O sub 3 anti-reflection layer were optimized to achieve maximum photo-thermal conversion efficiency at 80 deg. C under concentration factors of 1-20 using the downhill simplex method in multi-dimensions in the numerical calculation. The dielectric function and the complex refractive index of Zr-ZrO sub 2 cermet materials were calculated using Sheng's approximation. Optimization calculations show that Al sub 2 O sub 3 /Zr-ZrO sub 2 /Al solar coatings with two cermet layers and three cermet layers have nearly identical solar absorptance, emittance and photo-thermal conversion efficiency that are much better than those for films with one cermet layer. The optimized Al sub 2 O sub 3 /Zr-ZrO sub 2 /Al solar coating film w...

  15. Functionally graded material of 304L stainless steel and inconel 625 fabricated by directed energy deposition: Characterization and thermodynamic modeling

    International Nuclear Information System (INIS)

    Carroll, Beth E.; Otis, Richard A.; Borgonia, John Paul; Suh, Jong-ook; Dillon, R. Peter; Shapiro, Andrew A.; Hofmann, Douglas C.; Liu, Zi-Kui; Beese, Allison M.

    2016-01-01

    Many engineering applications, particularly in extreme environments, require components with properties that vary with location in the part. Functionally graded materials (FGMs), which possess gradients in properties such as hardness or density, are a potential solution to address these requirements. The laser-based additive manufacturing process of directed energy deposition (DED) can be used to fabricate metallic parts with a gradient in composition by adjusting the volume fraction of metallic powders delivered to the melt pool as a function of position. As this is a fusion process, secondary phases may develop in the gradient zone during solidification that can result in undesirable properties in the part. This work describes experimental and thermodynamic studies of a component built from 304L stainless steel incrementally graded to Inconel 625. The microstructure, chemistry, phase composition, and microhardness as a function of position were characterized by microscopy, energy dispersive spectroscopy, X-ray diffraction, and microindentation. Particles of secondary phases were found in small amounts within cracks in the gradient zone. These were ascertained to consist of transition metal carbides by experimental results and thermodynamic calculations. The study provides a combined experimental and thermodynamic computational modeling approach toward the fabrication and evaluation of a functionally graded material made by DED additive manufacturing.

  16. A modeling study of the effect of gravity on airflow distribution and particle deposition in the lung.

    Science.gov (United States)

    Asgharian, Bahman; Price, Owen; Oberdörster, Gunter

    2006-06-01

    Inhalation of particles generated as a result of thermal degradation from fire or smoke, as may occur on spacecraft, is of major health concern to space-faring countries. Knowledge of lung airflow and particle transport under different gravity environments is required to addresses this concern by providing information on particle deposition. Gravity affects deposition of particles in the lung in two ways. First, the airflow distribution among airways is changed in different gravity environments. Second, particle losses by sedimentation are enhanced with increasing gravity. In this study, a model of airflow distribution in the lung that accounts for the influence of gravity was used for a mathematical description of particle deposition in the human lung to calculate lobar, regional, and local deposition of particles in different gravity environments. The lung geometry used in the mathematical model contained five lobes that allowed the assessment of lobar ventilation distribution and variation of particle deposition. At zero gravity, it was predicted that all lobes of the lung expanded and contracted uniformly, independent of body position. Increased gravity in the upright position increased the expansion of the upper lobes and decreased expansion of the lower lobes. Despite a slight increase in predicted deposition of ultrafine particles in the upper lobes with decreasing gravity, deposition of ultrafine particles was generally predicted to be unaffected by gravity. Increased gravity increased predicted deposition of fine and coarse particles in the tracheobronchial region, but that led to a reduction or even elimination of deposition in the alveolar region for coarse particles. The results from this study show that existing mathematical models of particle deposition at 1 G can be extended to different gravity environments by simply correcting for a gravity constant. Controlled studies in astronauts on future space missions are needed to validate these predictions.

  17. Total deposition of inhaled particles related to age: comparison with age-dependent model calculations

    International Nuclear Information System (INIS)

    Becquemin, M.H.; Bouchikhi, A.; Yu, C.P.; Roy, M.

    1991-01-01

    To compare experimental data with age-dependent model calculations, total airway deposition of polystyrene aerosols (1, 2.05 and 2.8 μm aerodynamic diameter) was measured in ten adults, twenty children aged 12 to 15 years, ten children aged 8 to 12, and eleven under 8 years old. Ventilation was controlled, and breathing patterns were appropriate for each age, either at rest or at light exercise. Individually, deposition percentages increased with particle size and also from rest to exercise, except in children under 12 years, in whom they decreased from 20-21.5 to 14-14.5 for 1 μm particles and from 36.8-36.9 to 32.2-33.1 for 2.05 μm particles. Comparisons with the age-dependent model showed that, at rest, the observed data concerning children agreed with those predicted and were close to the adults' values, when the latter were higher than predicted. At exercise, child data were lower than predicted and lower than adult experimental data, when the latter agreed fairly well with the model. (author)

  18. Modeling of Paleo Heat-and-Mass Trasport for Prognosys of Mineral Deposits Using GIS

    International Nuclear Information System (INIS)

    Cherkasov, Sergei; Vishnevskaya, Natalia; Cassard, Daniel; Sterligov, Boris; Arbuzova, Ekaterina

    2008-01-01

    The heat-and-mass flow from the mantle to the surface can be characterized by the three basic models. The first one represents just a convective heating of the crust by the hot mantle. Two other kinds of the heat-and-mass flow system are rather anomalous and sometimes serve as an engine for launching ore-forming processes. The second model describes a pipe-like conductive heat-and-flow system reasoning appearance of mafic-ultramafic intrusions coming to the surface directly from the upper mantle. The third model corresponds with a complicated convective-conductive process involving melting of crustal rocks, and forming magmatic chambers inside the crust. Analysis of gravimetric and seismic data using geographic informational systems allows us to locate elements of the anomalous heat-and-flow systems. Some of the elements (their projection on the surface) correlate with position of the known deposits of gold, silver, tungsten, tin, sometimes--molybdenum and base metals. The results of studies conducted by the Russian-French Metallogenic Laboratory in the frames of crystalline shields of Russia demonstrate location of 87% of the known gold-bearing deposits inside the zones defined by such analysis

  19. Increasing dimension of structures by 4D printing shape memory polymers via fused deposition modeling

    Science.gov (United States)

    Hu, G. F.; Damanpack, A. R.; Bodaghi, M.; Liao, W. H.

    2017-12-01

    The main objective of this paper is to introduce a 4D printing method to program shape memory polymers (SMPs) during fabrication process. Fused deposition modeling (FDM) as a filament-based printing method is employed to program SMPs during depositing the material. This method is implemented to fabricate complicated polymeric structures by self-bending features without need of any post-programming. Experiments are conducted to demonstrate feasibility of one-dimensional (1D)-to 2D and 2D-to-3D self-bending. It is shown that 3D printed plate structures can transform into masonry-inspired 3D curved shell structures by simply heating. Good reliability of SMP programming during printing process is also demonstrated. A 3D macroscopic constitutive model is established to simulate thermo-mechanical features of the printed SMPs. Governing equations are also derived to simulate programming mechanism during printing process and shape change of self-bending structures. In this respect, a finite element formulation is developed considering von-Kármán geometric nonlinearity and solved by implementing iterative Newton-Raphson scheme. The accuracy of the computational approach is checked with experimental results. It is demonstrated that the theoretical model is able to replicate the main characteristics observed in the experiments. This research is likely to advance the state of the art FDM 4D printing, and provide pertinent results and computational tool that are instrumental in design of smart materials and structures with self-bending features.

  20. Modeling of liquid-metal corrosion/deposition in a fusion reactor blanket

    International Nuclear Information System (INIS)

    Malang, S.; Smith, D.L.

    1984-04-01

    A model has been developed for the investigation of the liquid-metal corrosion and the corrosion product transport in a liquid-metal-cooled fusion reactor blanket. The model describes the two-dimensional transport of wall material in the liquid-metal flow and is based on the following assumptions: (1) parallel flow in a straight circular tube; (2) transport of wall material perpendicular to the flow direction by diffusion and turbulent exchange; in flow direction by the flow motion only; (3) magnetic field causes uniform velocity profile with thin boundary layer and suppresses turbulent mass exchange; and (4) liquid metal at the interface is saturated with wall material. A computer code based on this model has been used to analyze the corrosion of ferritic steel by lithium lead and the deposition of wall material in the cooler part of a loop. Three cases have been investigated: (1) ANL forced convection corrosion experiment (without magnetic field); (2) corrosion in the MARS liquid-metal-cooled blanket (with magnetic field); and (3) deposition of wall material in the corrosion product cleanup system of the MARS blanket loop

  1. Lanchester-Type Models of Warfare, Volume II

    OpenAIRE

    Taylor, James G.

    1980-01-01

    This monograph is a comprehensive treatist on Lanchester-type models of warfare, i.e. differential-equation models of attrition in force-on-force combat operations. Its goal is to provide both an introduction to and current-state-of-the-art overview of Lanchester-type models of warfare as well as a comprehensive and unified in-depth treatment of them. Both deterministic as well as stochastic models are considered. Such models have been widely used in the United States and elsewhere for the...

  2. Feature scale modeling for etching and deposition processes in semiconductor manufacturing

    International Nuclear Information System (INIS)

    Pyka, W.

    2000-04-01

    Simulation of etching and deposition processes as well as three-dimensional geometry generation are important issues in state of the art TCAD applications. Three-dimensional effects are gaining importance for semiconductor devices and for their interconnects. Therefore a strictly physically based simulation of their topography is required. Accurate investigation of single etching and deposition processes has become equally important as process integration. Within this context several aspects of three-dimensional topography simulation have been covered by this thesis and new and interesting results have been achieved in various areas. The algorithmic core of the cell-based structuring element surface propagation method has been optimized and has been eliminated from its position as factor which predominantly determines the required CPU time. In parallel with investigated optimization techniques and required by various process models, the implementation of the surface normal calculation and the special handling of voids and unconnected parts of the geometry has been completed in three dimensions. A process-step-based solid modeling tool which incorporates layout data as well as aerial image simulation has been supplied. It can be coupled with the topography simulation and includes simple geometrically based models for CMP and oxidation. In the presented combination, the tool makes use of the design information stored in the layout file, combines it with the manufacturing recipe, and hence is extremely helpful for the automatic generation of three-dimensional structures. Its usefulness has been proven with several interconnect examples. Regarding topography models, resist development not only turned out to be very helpful for predicting exposed and etched resist profiles within a rigorous lithography simulation, but, by means of benchmark examples, also demonstrated the extraordinary stability of the proposed cellular surface movement algorithm. With respect to

  3. Finite element modeling of deposition of ceramic material during SLM additive manufacturing

    Directory of Open Access Journals (Sweden)

    Chen Qiang

    2016-01-01

    Full Text Available A three dimensional model for material deposition in Selective Laser Melting (SLM with application to Al2O3-ZrO2 eutectic ceramic is presented. As the material is transparent to laser, dopants are added to increase the heat absorption efficiency. Based on Beer-Lambert law, a volumetric heat source model taking into account the material absorption is derived. The Level Set method with multiphase homogenization is used to track the shape of deposed bead and the thermodynamic is coupled to calculate the melting-solidification path. The shrinkage during consolidation from powder to compact medium is modeled by a compressible Newtonian constitutive law. A semi-implicit formulation of surface tension is used, which permits a stable resolution to capture the gas-liquid interface. The formation of droplets is obtained and slight waves of melt pool are observed. The influence of different process parameters on temperature distribution, melt pool profiles and bead shapes is discussed.

  4. Modelling the ecosystem effects of nitrogen deposition: Model of Ecosystem Retention and Loss of Inorganic Nitrogen (MERLIN

    Directory of Open Access Journals (Sweden)

    B. J. Cosby

    1997-01-01

    Full Text Available A catchment-scale mass-balance model of linked carbon and nitrogen cycling in ecosystems has been developed for simulating leaching losses of inorganic nitrogen. The model (MERLIN considers linked biotic and abiotic processes affecting the cycling and storage of nitrogen. The model is aggregated in space and time and contains compartments intended to be observable and/or interpretable at the plot or catchment scale. The structure of the model includes the inorganic soil, a plant compartment and two soil organic compartments. Fluxes in and out of the ecosystem and between compartments are regulated by atmospheric deposition, hydrological discharge, plant uptake, litter production, wood production, microbial immobilization, mineralization, nitrification, and denitrification. Nitrogen fluxes are controlled by carbon productivity, the C:N ratios of organic compartments and inorganic nitrogen in soil solution. Inputs required are: 1 temporal sequences of carbon fluxes and pools- 2 time series of hydrological discharge through the soils, 3 historical and current external sources of inorganic nitrogen; 4 current amounts of nitrogen in the plant and soil organic compartments; 5 constants specifying the nitrogen uptake and immobilization characteristics of the plant and soil organic compartments; and 6 soil characteristics such as depth, porosity, bulk density, and anion/cation exchange constants. Outputs include: 1 concentrations and fluxes of NO3 and NH4 in soil solution and runoff; 2 total nitrogen contents of the organic and inorganic compartments; 3 C:N ratios of the aggregated plant and soil organic compartments; and 4 rates of nitrogen uptake and immobilization and nitrogen mineralization. The behaviour of the model is assessed for a combination of land-use change and nitrogen deposition scenarios in a series of speculative simulations. The results of the simulations are in broad agreement with observed and hypothesized behaviour of nitrogen

  5. Stimulation model for lenticular sands: Volume 2, Users manual

    Energy Technology Data Exchange (ETDEWEB)

    Rybicki, E.F.; Luiskutty, C.T.; Sutrick, J.S.; Palmer, I.D.; Shah, G.H.; Tomutsa, L.

    1987-07-01

    This User's Manual contains information for four fracture/proppant models. TUPROP1 contains a Geertsma and de Klerk type fracture model. The section of the program utilizing the proppant fracture geometry data from the pseudo three-dimensional highly elongated fracture model is called TUPROPC. The analogous proppant section of the program that was modified to accept fracture shape data from SA3DFRAC is called TUPROPS. TUPROPS also includes fracture closure. Finally there is the penny fracture and its proppant model, PENNPROP. In the first three chapters, the proppant sections are based on the same theory for determining the proppant distribution but have modifications to support variable height fractures and modifications to accept fracture geometry from three different fracture models. Thus, information about each proppant model in the User's Manual builds on information supplied in the previous chapter. The exception to the development of combined treatment models is the penny fracture and its proppant model. In this case, a completely new proppant model was developed. A description of how to use the combined treatment model for the penny fracture is contained in Chapter 4. 2 refs.

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

    Directory of Open Access Journals (Sweden)

    M. Kajino

    2012-11-01

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

  7. 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

    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...... differ in the description of the sticking probability of impacted particles: model #1 employs a reference viscosity in the description of the sticking probability, while model #2 combines impaction of viscoelastic particles on a solid surface with particle capture by a viscous surface. Both models were...

  8. Phenomenological modelling of CHF in annular flow in annuli using new models of droplet deposition and entrainment

    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., E-mail: g.hewitt@imperial.ac.uk [Department of Chemical Engineering, Imperial College, London SW7 2BY (United Kingdom)

    2016-08-15

    Highlights: • A phenomenological model to predict the CHF for flows in annuli is described. • New correlations of droplet entrainment and deposition are used. • The present model has good predictive capability in predicting CHF in annuli. - Abstract: In this paper, we present a phenomenological model to predict the CHF (critical heat flux) for upward annular flow in heated vertical annuli. In present model, a new set of correlations of droplet deposition and entrainment in annuli was used which were verified by comparison with the data of Moeck (1970) for developing liquid films in adiabatic annuli. In the results presented here, these new correlations have been used to predict 2249 independent data on critical heat flux (CHF) obtained both regarding internal heating of the rod as well as simultaneous heating of the rod and the outer tube in six heated vertical annuli under various mass flow rate, pressure and inlet quality and where the conditions were such that (as is most common) the CHF condition occurred in the annular flow regime. The comparisons between the calculated and measured CHFs showed that the present model has good predictive capability in predicting CHF.

  9. Optimal models of extreme volume-prices are time-dependent

    International Nuclear Information System (INIS)

    Rocha, Paulo; Boto, João Pedro; Raischel, Frank; Lind, Pedro G

    2015-01-01

    We present evidence that the best model for empirical volume-price distributions is not always the same and it strongly depends in (i) the region of the volume-price spectrum that one wants to model and (ii) the period in time that is being modelled. To show these two features we analyze stocks of the New York stock market with four different models: Γ, Γ-inverse, log-normal, and Weibull distributions. To evaluate the accuracy of each model we use standard relative deviations as well as the Kullback-Leibler distance and introduce an additional distance particularly suited to evaluate how accurate are the models for the distribution tails (large volume-price). Finally we put our findings in perspective and discuss how they can be extended to other situations in finance engineering

  10. 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-09-15

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

  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. PREDICTION OF THE MIXING ENTHALPIES OF BINARY LIQUID ALLOYS BY MOLECULAR INTERACTION VOLUME MODEL

    Institute of Scientific and Technical Information of China (English)

    H.W.Yang; D.P.Tao; Z.H.Zhou

    2008-01-01

    The mixing enthalpies of 23 binary liquid alloys are calculated by molecular interaction volume model (MIVM), which is a two-parameter model with the partial molar infinite dilute mixing enthalpies. The predicted values are in agreement with the experimental data and then indicate that the model is reliable and convenient.

  14. A model for vented deflagration of hydrogen in a volume

    International Nuclear Information System (INIS)

    Mulpuru, S.R.; Wilkin, G.B.

    1982-02-01

    A simple model was constructed to predict the property transients resulting from the deflagration of a combustible mixture in a sphere or cylinder with venting of the gas mixture to the environment. A computer program VENT, was written to solve the model equation. The model will be particularly useful for studying hydrogen burning effects in loss-of-coolant plus losss of emergency coolant accidents in CANDU reactors

  15. 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.

  16. Accounting for Field-Scale Dry Deposition in Backward Lagrangian Stochastic Dispersion Modelling of NH3 Emissions

    Directory of Open Access Journals (Sweden)

    Christoph Häni

    2018-04-01

    Full Text Available A controlled ammonia (NH3 release experiment was performed at a grassland site. The aim was to quantify the effect of dry deposition between the source and the receptors (NH3 measurement locations on emission rate estimates by means of inverse dispersion modelling. NH3 was released for three hours at a constant rate of Q = 6.29 mg s−1 from a grid of 36 orifices spread over an area of 250 m2. The increase in line-integrated NH3 concentration was measured with open-path optical miniDOAS devices at different locations downwind of the artificial source. Using a backward Lagrangian stochastic (bLS dispersion model (bLSmodelR, the fraction of the modelled release rate to the emitted NH3 ( Q bLS / Q was calculated from the measurements of the individual instruments. Q bLS / Q was found to be systematically lower than 1, on average between 0.69 and 0.91, depending on the location of the receptor. We hypothesized that NH3 dry deposition to grass and soil surfaces was the main factor responsible for the observed depletion of NH3 between source and receptor. A dry deposition algorithm based on a deposition velocity approach was included in the bLS modelling. Model deposition velocities were evaluated from a ‘big-leaf’ canopy resistance analogy. Canopy resistances (generally termed R c that provided Q bLS / Q = 1 ranged from 75 to 290 s m−1, showing that surface removal of NH3 by dry deposition can plausibly explain the original underestimation of Q bLS / Q . The inclusion of a dry deposition process in dispersion modelling is crucial for emission estimates, which are based on concentration measurements of depositing tracers downwind of homogeneous area sources or heterogeneously-distributed hot spots, such as, e.g., urine patches on pastures in the case of NH3.

  17. Mechanistic Fluid Transport Model to Estimate Gastrointestinal Fluid Volume and Its Dynamic Change Over Time.

    Science.gov (United States)

    Yu, Alex; Jackson, Trachette; Tsume, Yasuhiro; Koenigsknecht, Mark; Wysocki, Jeffrey; Marciani, Luca; Amidon, Gordon L; Frances, Ann; Baker, Jason R; Hasler, William; Wen, Bo; Pai, Amit; Sun, Duxin

    2017-11-01

    Gastrointestinal (GI) fluid volume and its dynamic change are integral to study drug disintegration, dissolution, transit, and absorption. However, key questions regarding the local volume and its absorption, secretion, and transit remain unanswered. The dynamic fluid compartment absorption and transit (DFCAT) model is proposed to estimate in vivo GI volume and GI fluid transport based on magnetic resonance imaging (MRI) quantified fluid volume. The model was validated using GI local concentration of phenol red in human GI tract, which was directly measured by human GI intubation study after oral dosing of non-absorbable phenol red. The measured local GI concentration of phenol red ranged from 0.05 to 168 μg/mL (stomach), to 563 μg/mL (duodenum), to 202 μg/mL (proximal jejunum), and to 478 μg/mL (distal jejunum). The DFCAT model characterized observed MRI fluid volume and its dynamic changes from 275 to 46.5 mL in stomach (from 0 to 30 min) with mucus layer volume of 40 mL. The volumes of the 30 small intestine compartments were characterized by a max of 14.98 mL to a min of 0.26 mL (0-120 min) and a mucus layer volume of 5 mL per compartment. Regional fluid volumes over 0 to 120 min ranged from 5.6 to 20.38 mL in the proximal small intestine, 36.4 to 44.08 mL in distal small intestine, and from 42 to 64.46 mL in total small intestine. The DFCAT model can be applied to predict drug dissolution and absorption in the human GI tract with future improvements.

  18. Improvement and Validation of an Aerosol Deposition Model in the GAMMA-FP, a Fission Product Analysis Module for VHTRs

    International Nuclear Information System (INIS)

    Yoon, Churl; Lim, Hong Sik

    2013-01-01

    GAMMA-FP (GAs Multicomponent Mixture Analysis-Fission Products module), consists of gaseous and aerosol fission product analysis modules. The aerosol FP module adopts a multi-component and multi-sectional aerosol analysis model that has been developed based on the MAEROS model. For the first work of FP module development, the MAEROS model has been implemented and examined against some analytic solutions and experimental data by Yoo et al. An aerosol transport model was developed and implemented in the GAMMA-FP code, and verified. In this study, the aerosol deposition model in the GAMMA-FP code was improved by adopting recent achievements, and was validated against an experimental data available. The aerosol deposition model in the GAMMA-FP code has been improved and successfully validated against the STORM SR-11 deposition test. The simulation with the improved deposition model predicted the matched results with the experimental data well. For future studies, the aerosol deposition model by flow irregularities will be implemented and validated against the TRANSAT bend effect test

  19. Improvement and Validation of an Aerosol Deposition Model in the GAMMA-FP, a Fission Product Analysis Module for VHTRs

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Churl; Lim, Hong Sik [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    GAMMA-FP (GAs Multicomponent Mixture Analysis-Fission Products module), consists of gaseous and aerosol fission product analysis modules. The aerosol FP module adopts a multi-component and multi-sectional aerosol analysis model that has been developed based on the MAEROS model. For the first work of FP module development, the MAEROS model has been implemented and examined against some analytic solutions and experimental data by Yoo et al. An aerosol transport model was developed and implemented in the GAMMA-FP code, and verified. In this study, the aerosol deposition model in the GAMMA-FP code was improved by adopting recent achievements, and was validated against an experimental data available. The aerosol deposition model in the GAMMA-FP code has been improved and successfully validated against the STORM SR-11 deposition test. The simulation with the improved deposition model predicted the matched results with the experimental data well. For future studies, the aerosol deposition model by flow irregularities will be implemented and validated against the TRANSAT bend effect test.

  20. 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.

  1. A depositional model for the Taylor coal bed, Martin and Johnson counties, eastern Kentucky

    Science.gov (United States)

    Andrews, W.M.; Hower, J.C.; Ferm, J.C.; Evans, S.D.; Sirek, N.S.; Warrell, M.; Eble, C.F.

    1996-01-01

    This study investigated the Taylor coal bed in Johnson and Martin counties, eastern Kentucky, using field and petrographic techniques to develop a depositional model of the coal bed. Petrography and chemistry of the coal bed were examined. Multiple benches of the Taylor coal bed were correlated over a 10 km distance. Three sites were studied in detail. The coal at the western and eastern sites were relatively thin and split by thick clastic partings. The coal at the central site was the thickest and unsplit. Two major clastic partings are included in the coal bed. Each represents a separate and distinct fluvial splay. The Taylor is interpreted to have developed on a coastal plain with periodic flooding from nearby, structurally-controlled fluvial systems. Doming is unlikely due to the petrographic and chemical trends, which are inconsistent with modern Indonesian models. The depositional history and structural and stratigraphic setting suggest contemporaneous structural influence on thickness and quality of the Taylor coal bed in this area.

  2. Combining electrospinning and fused deposition modeling for the fabrication of a hybrid vascular graft

    International Nuclear Information System (INIS)

    Centola, M; Rainer, A; Trombetta, M; Spadaccio, C; Genovese, J A; De Porcellinis, S

    2010-01-01

    Tissue engineering of blood vessels is a promising strategy in regenerative medicine with a broad spectrum of potential applications. However, many hurdles for tissue-engineered vascular grafts, such as poor mechanical properties, thrombogenicity and cell over-growth inside the construct, need to be overcome prior to the clinical application. To surmount these shortcomings, we developed a poly-l-lactide (PLLA)/poly-ε-caprolactone (PCL) scaffold releasing heparin by a combination of electrospinning and fused deposition modeling technique. PLLA/heparin scaffolds were produced by electrospinning in tubular shape and then fused deposition modeling was used to armor the tube with a single coil of PCL on the outer layer to improve mechanical properties. Scaffolds were then seeded with human mesenchymal stem cells (hMSCs) and assayed in terms of morphology, mechanical tensile strength, cell viability and differentiation. This particular scaffold design allowed the generation of both a drug delivery system amenable to surmount thrombogenic issues and a microenvironment able to induce endothelial differentiation. At the same time, the PCL external coiling improved mechanical resistance of the microfibrous scaffold. By the combination of two notable techniques in biofabrication-electrospinning and FDM-and exploiting the biological effects of heparin, we developed an ad hoc differentiating device for hMSCs seeding, able to induce differentiation into vascular endothelium.

  3. Combining electrospinning and fused deposition modeling for the fabrication of a hybrid vascular graft

    Energy Technology Data Exchange (ETDEWEB)

    Centola, M; Rainer, A; Trombetta, M [Laboratory of Chemistry and Biomaterials, CIR-Center of Integrated Research, University Campus Bio-Medico of Rome (Italy); Spadaccio, C; Genovese, J A [Area of Cardiovascular Surgery, CIR-Center of Integrated Research, University Campus Bio-Medico of Rome (Italy); De Porcellinis, S, E-mail: m.trombetta@unicampus.i [Complex Systems and Security Laboratory, CIR-Center of Integrated Research, University Campus Bio-Medico of Rome (Italy)

    2010-03-15

    Tissue engineering of blood vessels is a promising strategy in regenerative medicine with a broad spectrum of potential applications. However, many hurdles for tissue-engineered vascular grafts, such as poor mechanical properties, thrombogenicity and cell over-growth inside the construct, need to be overcome prior to the clinical application. To surmount these shortcomings, we developed a poly-l-lactide (PLLA)/poly-epsilon-caprolactone (PCL) scaffold releasing heparin by a combination of electrospinning and fused deposition modeling technique. PLLA/heparin scaffolds were produced by electrospinning in tubular shape and then fused deposition modeling was used to armor the tube with a single coil of PCL on the outer layer to improve mechanical properties. Scaffolds were then seeded with human mesenchymal stem cells (hMSCs) and assayed in terms of morphology, mechanical tensile strength, cell viability and differentiation. This particular scaffold design allowed the generation of both a drug delivery system amenable to surmount thrombogenic issues and a microenvironment able to induce endothelial differentiation. At the same time, the PCL external coiling improved mechanical resistance of the microfibrous scaffold. By the combination of two notable techniques in biofabrication-electrospinning and FDM-and exploiting the biological effects of heparin, we developed an ad hoc differentiating device for hMSCs seeding, able to induce differentiation into vascular endothelium.

  4. Quantitative analysis of CT brain images: a statistical model incorporating partial volume and beam hardening effects

    International Nuclear Information System (INIS)

    McLoughlin, R.F.; Ryan, M.V.; Heuston, P.M.; McCoy, C.T.; Masterson, J.B.

    1992-01-01

    The purpose of this study was to construct and evaluate a statistical model for the quantitative analysis of computed tomographic brain images. Data were derived from standard sections in 34 normal studies. A model representing the intercranial pure tissue and partial volume areas, with allowance for beam hardening, was developed. The average percentage error in estimation of areas, derived from phantom tests using the model, was 28.47%. We conclude that our model is not sufficiently accurate to be of clinical use, even though allowance was made for partial volume and beam hardening effects. (author)

  5. Regional air-quality and acid-deposition modeling and the role for visualization

    International Nuclear Information System (INIS)

    Novak, J.H.; Dennis, R.L.

    1991-11-01

    The U.S. Environmental Protection Agency (EPA) uses air quality and deposition models to advance the scientific understanding of basic physical and chemical processes related to air pollution, and to assess the effectiveness of alternative emissions control strategies. The paper provides a brief technical description of several regional scale atmospheric models, their current use within EPA, and related data analysis issues. Spatial analysis is a key component in the evaluation and interpretation of the model predictions. Thus, the authors highlight several types of analysis enhancements focusing on those related to issues of spatial scale, user access to models and analysis tools, and consolidation of air quality modeling and graphical analysis capabilities. They discuss their initial experience with a Geographical Information System (GIS) pilot project that generated the initial concepts for the design of an integrated modeling and analysis environment. And finally, they present current plans to evolve this modeling/visualization approach to a distributed, heterogeneous computing environment which enables any research scientist or policy analyst to use high performance visualization techniques from his/her desktop

  6. A stochastic model of solid state thin film deposition: Application to chalcopyrite growth

    Directory of Open Access Journals (Sweden)

    Robert J. Lovelett

    2016-04-01

    Full Text Available Developing high fidelity quantitative models of solid state reaction systems can be challenging, especially in deposition systems where, in addition to the multiple competing processes occurring simultaneously, the solid interacts with its atmosphere. In this work, we develop a model for the growth of a thin solid film where species from the atmosphere adsorb, diffuse, and react with the film. The model is mesoscale and describes an entire film with thickness on the order of microns. Because it is stochastic, the model allows us to examine inhomogeneities and agglomerations that would be impossible to characterize with deterministic methods. We demonstrate the modeling approach with the example of chalcopyrite Cu(InGa(SeS2 thin film growth via precursor reaction, which is a common industrial method for fabricating thin film photovoltaic modules. The model is used to understand how and why through-film variation in the composition of Cu(InGa(SeS2 thin films arises and persists. We believe that the model will be valuable as an effective quantitative description of many other materials systems used in semiconductors, energy storage, and other fast-growing industries.

  7. 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

  8. 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.

  9. A hybrid ARIMA and neural network model applied to forecast catch volumes of Selar crumenophthalmus

    Science.gov (United States)

    Aquino, Ronald L.; Alcantara, Nialle Loui Mar T.; Addawe, Rizavel C.

    2017-11-01

    The Selar crumenophthalmus with the English name big-eyed scad fish, locally known as matang-baka, is one of the fishes commonly caught along the waters of La Union, Philippines. The study deals with the forecasting of catch volumes of big-eyed scad fish for commercial consumption. The data used are quarterly caught volumes of big-eyed scad fish from 2002 to first quarter of 2017. This actual data is available from the open stat database published by the Philippine Statistics Authority (PSA)whose task is to collect, compiles, analyzes and publish information concerning different aspects of the Philippine setting. Autoregressive Integrated Moving Average (ARIMA) models, Artificial Neural Network (ANN) model and the Hybrid model consisting of ARIMA and ANN were developed to forecast catch volumes of big-eyed scad fish. Statistical errors such as Mean Absolute Errors (MAE) and Root Mean Square Errors (RMSE) were computed and compared to choose the most suitable model for forecasting the catch volume for the next few quarters. A comparison of the results of each model and corresponding statistical errors reveals that the hybrid model, ARIMA-ANN (2,1,2)(6:3:1), is the most suitable model to forecast the catch volumes of the big-eyed scad fish for the next few quarters.

  10. Modeling surface area to volume effects on borosilicate glass dissolution

    International Nuclear Information System (INIS)

    Bourcier, W.L.; Ebert, W.L.; Feng, X.

    1992-11-01

    We simulated the reaction of SRL-131 glass with equilibrated J-13 water in order to investigate the effects of surface area to volume ratio (SA/V) on glass dissolution. We show that glass-fluid ion exchange causes solution pH to rise to progressively higher values as SA/V increases. Because the ion exchange is rapid relative to the duration of the glass dissolution experiment, the pH effect does not scale with (SA/V)*time. Experiments compared at the same (SA/V)*time value therefore have different pHs, with higher pHs at higher SA/V ratios. Both experimental data and our simulation results show similar trends of increasing reaction rate as a function of SA/V ratio when scaled to (SA/V)*time. Glasses which react in systems of differing SA/V ratio therefore follow different reaction paths and high SA/V ratios cannot be used to generate data which accurately scales to long time periods unless the ion exchange effect is taken into account. We suggest some simple test designs which enable more reliable high. SA/V accelerated tests

  11. Measurement and modeling of advanced coal conversion processes, Volume III

    Energy Technology Data Exchange (ETDEWEB)

    Ghani, M.U.; Hobbs, M.L.; Hamblen, D.G. [and others

    1993-08-01

    A generalized one-dimensional, heterogeneous, steady-state, fixed-bed model for coal gasification and combustion is presented. The model, FBED-1, is a design and analysis tool that can be used to simulate a variety of gasification, devolatilization, and combustion processes. The model considers separate gas and solid temperatures, axially variable solid and gas flow rates, variable bed void fraction, coal drying, devolatilization based on chemical functional group composition, depolymerization, vaporization and crosslinking, oxidation, and gasification of char, and partial equilibrium in the gas phase.

  12. Measurement and modeling of advanced coal conversion processes, Volume II

    Energy Technology Data Exchange (ETDEWEB)

    Solomon, P.R.; Serio, M.A.; Hamblen, D.G. [and others

    1993-06-01

    A two dimensional, steady-state model for describing a variety of reactive and nonreactive flows, including pulverized coal combustion and gasification, is presented. The model, referred to as 93-PCGC-2 is applicable to cylindrical, axi-symmetric systems. Turbulence is accounted for in both the fluid mechanics equations and the combustion scheme. Radiation from gases, walls, and particles is taken into account using a discrete ordinates method. The particle phase is modeled in a lagrangian framework, such that mean paths of particle groups are followed. A new coal-general devolatilization submodel (FG-DVC) with coal swelling and char reactivity submodels has been added.

  13. Estimating volume of deposits associated with landslides on volcanic landscapes in the SW flank of the volcano Pico de Orizaba, Puebla-Veracruz

    Directory of Open Access Journals (Sweden)

    Gabriel Legorreta Paulín

    2017-03-01

    dangerous situation for more than 360 000 people living on the southern flank of the volcano Pico de Orizaba, where landslides along the hillslopes and the river system threaten towns like Cordova, Orizaba, Rio Blanco, Nogales and Ciudad Mendoza. Today the most common and dangerous landslides are associated with unconsolidated volcanic deposits and heavy seasonal rains. In this paper, the cause, distribution, and link between landslides and the volcanic landscape relief susceptibility are analyzed. Similarly, the volume of displaced material is estimated in order to characterize the landslide instability in volcanic terrains. The Río El Estado watershed on the southwestern flank of Pico de Orizaba volcano is selected to describe and analyze susceptible areas of gravitational processes. The study area allows to show a systematic methodology for landslide mapping and volume calculation in areas with scarce information. The methodology encompasses three main stages of analysis. In the first stage, background information is collected to provide context and establish a generalized characterization of landslide processes, landsforms and volumes within the study area. Background information includes the following maps: topographic, geologic, land use, climate, slope, slope curvature, contributing area, flow direction, saturation, reclassified hypsomety, reclassified slope, and morphography. By retrieval and on-off switching of the background information in the GIS, a base map is created to assist in the digitizing of landslides. The base map and the theoretical aspects of the geomorphological mapping help to develop a conceptual base of support for mapping landslides. Landslides are digitized directly into a geographic information system (GIS, and in parallel, a spatial geodatabase of landslides attributes (eg. size, volume, activity, landslide type, etc. is constructed. Previous landslide mapping in the study area is verified and new landslides are added to the landslide

  14. Volume and aboveground biomass models for dry Miombo woodland in Tanzania

    DEFF Research Database (Denmark)

    Mwakalukwa, Ezekiel Edward; Meilby, Henrik; Treue, Thorsten

    2014-01-01

    Tools to accurately estimate tree volume and biomass are scarce for most forest types in East Africa, including Tanzania. Based on a sample of 142 trees and 57 shrubs from a 6,065 ha area of dry miombo woodland in Iringa rural district in Tanzania, regression models were developed for volume...... and biomass of three important species, Brachystegia spiciformis Benth. (n=40), Combretum molle G. Don (n=41), and Dalbergia arbutifolia Baker (n=37) separately, and for broader samples of trees (28 species, n=72), shrubs (16 species, n=31), and trees and shrubs combined (44 species, n=104). Applied...... of the predictions tended to increase from general to species-specific models. Except for a few volume and biomass models developed for shrubs, all models had R2 values of 96–99%. Thus, the models appear robust and should be applicable to forests with similar site conditions, species, and diameter ranges....

  15. Predictive Software Cost Model Study. Volume I. Final Technical Report.

    Science.gov (United States)

    1980-06-01

    development phase to identify computer resources necessary to support computer programs after transfer of program manangement responsibility and system... classical model development with refinements specifically applicable to avionics systems. The refinements are the result of the Phase I literature search

  16. Meteorological modeling of arrival and deposition of fallout at intermediate distances downwind of the Nevada Test Site

    International Nuclear Information System (INIS)

    Cederwall, R.T.; Peterson, K.R.

    1990-01-01

    A three-dimensional atmospheric transport and diffusion model is used to calculate the arrival and deposition of fallout from 13 selected nuclear tests at the Nevada Test Site (NTS) in the 1950s. Results are used to extend NTS fallout patterns to intermediate downwind distances (300 to 1200 km). The radioactive cloud is represented in the model by a population of Lagrangian marker particles, with concentrations calculated on an Eulerian grid. Use of marker particles, with fall velocities dependent on particle size, provides a realistic simulation of fallout as the debris cloud travels downwind. The three-dimensional wind field is derived from observed data, adjusted for mass consistency. Terrain is represented in the grid, which extends up to 1200 km downwind of NTS and has 32-km horizontal resolution and 1-km vertical resolution. Ground deposition is calculated by a deposition-velocity approach. Source terms and relationships between deposition and exposure rate are based on work by Hicks. Uncertainty in particle size and vertical distributions within the debris cloud (and stem) allow for some model tuning to better match measured ground-deposition values. Particle trajectories representing different sizes and starting heights above ground zero are used to guide source specification. An hourly time history of the modeled fallout pattern as the debris cloud moves downwind provides estimates of fallout arrival times. Results for event HARRY illustrate the methodology. The composite deposition pattern for all 13 tests is characterized by two lobes extending out to the north-northeast and east-northeast, respectively, at intermediate distances from NTS. Arrival estimates, along with modeled deposition values, augment measured deposition data in the development of data bases at the county level

  17. LOGAM (Logistic Analysis Model). Volume 2. Users Manual.

    Science.gov (United States)

    1982-08-01

    as opposed to simulation models which represent a system’s behavior as a function of time. These latter classes of models are often complex. They...includes the cost of ammunition and missiles comsumed by the system being costed during unit training. Excluded is the cost of ammunition consumed during...data. The results obtained from sensitivity testing may be used to construct graphs which display the behavior of the maintenance concept over the range

  18. Energy and nutrient deposition and excretion in the reproducing sow: model development and evaluation

    DEFF Research Database (Denmark)

    Hansen, A V; Strathe, A B; Theil, Peter Kappel

    2014-01-01

    requirements for maintenance, and fetal and maternal growth were described. In the lactating module, a factorial approach was used to estimate requirements for maintenance, milk production, and maternal growth. The priority for nutrient partitioning was assumed to be in the order of maintenance, milk...... production, and maternal growth with body tissue losses constrained within biological limits. Global sensitivity analysis showed that nonlinearity in the parameters was small. The model outputs considered were the total protein and fat deposition, average urinary and fecal N excretion, average methane...... emission, manure carbon excretion, and manure production. The model was evaluated using independent data sets from the literature using root mean square prediction error (RMSPE) and concordance correlation coefficients. The gestation module predicted body fat gain better than body protein gain, which...

  19. Modeling and optimization of atomic layer deposition processes on vertically aligned carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Nuri Yazdani

    2014-03-01

    Full Text Available Many energy conversion and storage devices exploit structured ceramics with large interfacial surface areas. Vertically aligned carbon nanotube (VACNT arrays have emerged as possible scaffolds to support large surface area ceramic layers. However, obtaining conformal and uniform coatings of ceramics on structures with high aspect ratio morphologies is non-trivial, even with atomic layer deposition (ALD. Here we implement a diffusion model to investigate the effect of the ALD parameters on coating kinetics and use it to develop a guideline for achieving conformal and uniform thickness coatings throughout the depth of ultra-high aspect ratio structures. We validate the model predictions with experimental data from ALD coatings of VACNT arrays. However, the approach can be applied to predict film conformality as a function of depth for any porous topology, including nanopores and nanowire arrays.

  20. Modeling and optimization of atomic layer deposition processes on vertically aligned carbon nanotubes.

    Science.gov (United States)

    Yazdani, Nuri; Chawla, Vipin; Edwards, Eve; Wood, Vanessa; Park, Hyung Gyu; Utke, Ivo

    2014-01-01

    Many energy conversion and storage devices exploit structured ceramics with large interfacial surface areas. Vertically aligned carbon nanotube (VACNT) arrays have emerged as possible scaffolds to support large surface area ceramic layers. However, obtaining conformal and uniform coatings of ceramics on structures with high aspect ratio morphologies is non-trivial, even with atomic layer deposition (ALD). Here we implement a diffusion model to investigate the effect of the ALD parameters on coating kinetics and use it to develop a guideline for achieving conformal and uniform thickness coatings throughout the depth of ultra-high aspect ratio structures. We validate the model predictions with experimental data from ALD coatings of VACNT arrays. However, the approach can be applied to predict film conformality as a function of depth for any porous topology, including nanopores and nanowire arrays.

  1. Experimental study and modelling of deuterium thermal release from Be-D co-deposited layers

    Science.gov (United States)

    Baldwin, M. J.; Schwarz-Selinger, T.; Doerner, R. P.

    2014-07-01

    A study of the thermal desorption of deuterium from 1 µm thick co-deposited Be-(0.1)D layers formed at 330 K by a magnetron sputtering technique is reported. A range of thermal desorption rates 0 ⩽ β ⩽ 1.0 K s-1 are explored with a view to studying the effectiveness of the proposed ITER wall and divertor bake procedure (β = 0 K s-1) to be carried out at 513 and 623 K. Fixed temperature bake durations up to 24 h are examined. The experimental thermal release data are used to validate a model input into the Tritium Migration and Analysis Program (TMAP-7). Good agreement with experiment is observed for a TMAP-7 model incorporating trap populations of activation energies for D release of 0.80 and 0.98 eV, and a dynamically computed surface D atomic to molecular recombination rate.

  2. 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

  3. Prediction of resource volumes at untested locations using simple local prediction models

    Science.gov (United States)

    Attanasi, E.D.; Coburn, T.C.; Freeman, P.A.

    2006-01-01

    This paper shows how local spatial nonparametric prediction models can be applied to estimate volumes of recoverable gas resources at individual undrilled sites, at multiple sites on a regional scale, and to compute confidence bounds for regional volumes based on the distribution of those estimates. An approach that combines cross-validation, the jackknife, and bootstrap procedures is used to accomplish this task. Simulation experiments show that cross-validation can be applied beneficially to select an appropriate prediction model. The cross-validation procedure worked well for a wide range of different states of nature and levels of information. Jackknife procedures are used to compute individual prediction estimation errors at undrilled locations. The jackknife replicates also are used with a bootstrap resampling procedure to compute confidence bounds for the total volume. The method was applied to data (partitioned into a training set and target set) from the Devonian Antrim Shale continuous-type gas play in the Michigan Basin in Otsego County, Michigan. The analysis showed that the model estimate of total recoverable volumes at prediction sites is within 4 percent of the total observed volume. The model predictions also provide frequency distributions of the cell volumes at the production unit scale. Such distributions are the basis for subsequent economic analyses. ?? Springer Science+Business Media, LLC 2007.

  4. A physical multifield model predicts the development of volume and structure in the human brain

    Science.gov (United States)

    Rooij, Rijk de; Kuhl, Ellen

    2018-03-01

    The prenatal development of the human brain is characterized by a rapid increase in brain volume and a development of a highly folded cortex. At the cellular level, these events are enabled by symmetric and asymmetric cell division in the ventricular regions of the brain followed by an outwards cell migration towards the peripheral regions. The role of mechanics during brain development has been suggested and acknowledged in past decades, but remains insufficiently understood. Here we propose a mechanistic model that couples cell division, cell migration, and brain volume growth to accurately model the developing brain between weeks 10 and 29 of gestation. Our model accurately predicts a 160-fold volume increase from 1.5 cm3 at week 10 to 235 cm3 at week 29 of gestation. In agreement with human brain development, the cortex begins to form around week 22 and accounts for about 30% of the total brain volume at week 29. Our results show that cell division and coupling between cell density and volume growth are essential to accurately model brain volume development, whereas cell migration and diffusion contribute mainly to the development of the cortex. We demonstrate that complex folding patterns, including sinusoidal folds and creases, emerge naturally as the cortex develops, even for low stiffness contrasts between the cortex and subcortex.

  5. 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.)

  6. Parameters for modelling the interception and retention of deposits from atmosphere by grain and leafy vegetables

    International Nuclear Information System (INIS)

    Simmonds, J.R.; Linsley, G.S.

    1982-01-01

    The Normalised Specific Activity (NSA), a quantity which relates the concentration of a contaminant per unit mass of vegetation to its daily rate of ground deposition, has been used as the basis for determining interception factors and retention half-lives for radioactive contaminants deposited on grain and leafy vegetables. The values are for use in assessing contamination levels on crops at harvest during condition of continuous deposition. The approach implicitly takes account of other processes which influence foliar contamination, namely, translocation and dilution due to plant growth. The respective NSA values for grain and prepared leafy vegetables determined from several separate experimental studies are fairly constant and are of about the same level for fall-out strontium and caesium. There is evidence from previous studies on herbage to suggest that similar NSA values might be expected for other contaminants on grain and leafy vegetables. Plutonium is an exception in that NSA values for grain and prepared leafy vegetables are lower than those for the fission products by factors of between 5 and 10 depending upon the source of the contaminant. Consideration has been given to determining the most appropriate value of the fraction of activity transferred from grain to flour during refining. This is an element dependent parameter and the values estimated for strontium, caesium and plutonium are respectively 0.15, 0.5 and 0.1. The study has indicated the need for data in several areas in order to improve the capability to model interception and retention on field crops in continuous and acute release conditions. (author)

  7. Physiological Modeling of Responses to Upper vs Lower Lobe Lung Volume Reduction in Homogeneous Emphysema

    Directory of Open Access Journals (Sweden)

    Arschang eValipour

    2012-10-01

    Full Text Available Rationale: In clinical trials, homogeneous emphysema patients have responded well to upper lobe volume reduction but not lower lobe volume reduction. Materials/Methods: To understand the physiological basis for this observation, a computer model was developed to simulate the effects of upper and lower lobe lung volume reduction on RV/TLC and lung recoil in homogeneous emphysema.Results: Patients with homogeneous emphysema received either upper or lower lobe volume reduction therapy based on findings of radionucleotide scintigraphy scanning. CT analysis of lobar volumes showed that patients undergoing upper (n=18; -265 mL/site and lower lobe treatment (n=11; -217 mL/site experienced similar reductions in lung volume. However, only upper lobe treatment improved FEV1 (+11.1±14.7% vs -4.4±15.8% and RV/TLC (-5.4± 8.1% vs -2.4±8.6%. Model simulations provided an unexpected explanation for this response. Increases in transpulmonary pressure subsequent to volume reduction increased RV/TLC in upper lobe alveoli, while caudal shifts in airway closure decreased RV/TLC in lower lobe alveoli. Upper lobe treatment, which eliminates apical alveoli with high RV/TLC values, lowers the average RV/TLC of the lung. Conversely, lower lobe treatment, which eliminates caudal alveoli with low RV/TLC values, has less effect. Conclusions: Lower lobe treatment in homogeneous emphysema is uniformly less effective than upper lobe treatment.

  8. Determination of bone mineral volume fraction using impedance analysis and Bruggeman model

    Energy Technology Data Exchange (ETDEWEB)

    Ciuchi, Ioana Veronica; Olariu, Cristina Stefania, E-mail: oocristina@yahoo.com; Mitoseriu, Liliana, E-mail: lmtsr@uaic.ro

    2013-11-20

    Highlights: • Mineral volume fraction of a bone sample was determined. • Dielectric properties for bone sample and for the collagen type I were determined by impedance spectroscopy. • Bruggeman effective medium approximation was applied in order to evaluate mineral volume fraction of the sample. • The computed values were compared with ones derived from a histogram test performed on SEM micrographs. -- Abstract: Measurements by impedance spectroscopy and Bruggeman effective medium approximation model were employed in order to determine the mineral volume fraction of dry bone. This approach assumes that two or more phases are present into the composite: the matrix (environment) and the other ones are inclusion phases. A fragment of femur diaphysis dense bone from a young pig was investigated in its dehydrated state. Measuring the dielectric properties of bone and its main components (hydroxyapatite and collagen) and using the Bruggeman approach, the mineral volume filling factor was determined. The computed volume fraction of the mineral volume fraction was confirmed by a histogram test analysis based on the SEM microstructures. In spite of its simplicity, the method provides a good approximation for the bone mineral volume fraction. The method which uses impedance spectroscopy and EMA modeling can be further developed by considering the conductive components of the bone tissue as a non-invasive in situ impedance technique for bone composition evaluation and monitoring.

  9. Determination of bone mineral volume fraction using impedance analysis and Bruggeman model

    International Nuclear Information System (INIS)

    Ciuchi, Ioana Veronica; Olariu, Cristina Stefania; Mitoseriu, Liliana

    2013-01-01

    Highlights: • Mineral volume fraction of a bone sample was determined. • Dielectric properties for bone sample and for the collagen type I were determined by impedance spectroscopy. • Bruggeman effective medium approximation was applied in order to evaluate mineral volume fraction of the sample. • The computed values were compared with ones derived from a histogram test performed on SEM micrographs. -- Abstract: Measurements by impedance spectroscopy and Bruggeman effective medium approximation model were employed in order to determine the mineral volume fraction of dry bone. This approach assumes that two or more phases are present into the composite: the matrix (environment) and the other ones are inclusion phases. A fragment of femur diaphysis dense bone from a young pig was investigated in its dehydrated state. Measuring the dielectric properties of bone and its main components (hydroxyapatite and collagen) and using the Bruggeman approach, the mineral volume filling factor was determined. The computed volume fraction of the mineral volume fraction was confirmed by a histogram test analysis based on the SEM microstructures. In spite of its simplicity, the method provides a good approximation for the bone mineral volume fraction. The method which uses impedance spectroscopy and EMA modeling can be further developed by considering the conductive components of the bone tissue as a non-invasive in situ impedance technique for bone composition evaluation and monitoring

  10. Developing a stochastic traffic volume prediction model for public-private partnership projects

    Science.gov (United States)

    Phong, Nguyen Thanh; Likhitruangsilp, Veerasak; Onishi, Masamitsu

    2017-11-01

    Transportation projects require an enormous amount of capital investment resulting from their tremendous size, complexity, and risk. Due to the limitation of public finances, the private sector is invited to participate in transportation project development. The private sector can entirely or partially invest in transportation projects in the form of Public-Private Partnership (PPP) scheme, which has been an attractive option for several developing countries, including Vietnam. There are many factors affecting the success of PPP projects. The accurate prediction of traffic volume is considered one of the key success factors of PPP transportation projects. However, only few research works investigated how to predict traffic volume over a long period of time. Moreover, conventional traffic volume forecasting methods are usually based on deterministic models which predict a single value of traffic volume but do not consider risk and uncertainty. This knowledge gap makes it difficult for concessionaires to estimate PPP transportation project revenues accurately. The objective of this paper is to develop a probabilistic traffic volume prediction model. First, traffic volumes were estimated following the Geometric Brownian Motion (GBM) process. Monte Carlo technique is then applied to simulate different scenarios. The results show that this stochastic approach can systematically analyze variations in the traffic volume and yield more reliable estimates for PPP projects.

  11. Dynamic Monte-Carlo modeling of hydrogen retention and chemical erosion from Tore Supra deposits

    International Nuclear Information System (INIS)

    Rai, A.; Schneider, R.; Warrier, M.; Roubin, P.; Martin, C.

    2009-01-01

    A multi-scale model has been developed to study the hydrogen retention [A. Rai, R. Schneider, M. Warrier, J. Nucl. Mater. 374 (2008) 304] and chemical erosion of porous graphite. To model the chemical erosion process due to thermal hydrogen ions, Kueppers cycle [J. Kueppers, Surf. Sci. Rep. 22 (1995) 249; M. Wittmann, J. Kueppers, J. Nucl. Mater. 227 (1996) 186] has been introduced. The model is applied to study hydrogen transport in deposits collected from the leading edge of neutralizers of Tore Supra. The effect of internal structure on chemical erosion is studied. The MD study [E. Salonen et al., J. Nucl. Mater. 290-293 (2001) 144] shows that the experimentally observed decrease of erosion yield at higher fluxes is due to the decrease of carbon collision cross-section at a surface due to shielding by hydrogen atom already present on the surface. Inspired by this study, a simple multi-scale model is developed to describe the flux dependence of chemical erosion. The idea is to use the local chemistry effect from the Kueppers model to calculate the hydrocarbon molecule formation process and then to find the release probability of the produced hydrocarbon based on the purely geometrical constraints. The model represents quite well the trends in experimental data.

  12. 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

  13. Comparisons between a gas-phase model of silane chemical vapor deposition and laser-diagnostic measurements

    International Nuclear Information System (INIS)

    Breiland, W.G.; Coltrin, M.E.; Ho, P.

    1986-01-01

    Theoretical modeling and experimental measurements have been used to study gas-phase chemistry in the chemical vapor deposition (CVD) of silicon from silane. Pulsed laser Raman spectroscopy was used to obtain temperature profiles and to obtain absolute density profiles of silane during deposition at atmospheric and 6-Torr total pressures for temperatures ranging from 500 to 800 0 C. Laser-excited fluorescence was used to obtain relative density profiles of Si 2 during deposition at 740 0 C in helium with 0-12 Torr added hydrogen. These measurements are compared to predictions from the theoretical model of Coltrin, Kee, and Miller. The predictions agree qualitatively with experiment. These studies indicate that fluid mechanics and gas-phase chemical kinetics are important considerations in understanding the chemical vapor deposition process

  14. Analysis and forecast of railway coal transportation volume based on BP neural network combined forecasting model

    Science.gov (United States)

    Xu, Yongbin; Xie, Haihong; Wu, Liuyi

    2018-05-01

    The share of coal transportation in the total railway freight volume is about 50%. As is widely acknowledged, coal industry is vulnerable to the economic situation and national policies. Coal transportation volume fluctuates significantly under the new economic normal. Grasp the overall development trend of railway coal transportation market, have important reference and guidance significance to the railway and coal industry decision-making. By analyzing the economic indicators and policy implications, this paper expounds the trend of the coal transportation volume, and further combines the economic indicators with the high correlation with the coal transportation volume with the traditional traffic prediction model to establish a combined forecasting model based on the back propagation neural network. The error of the prediction results is tested, which proves that the method has higher accuracy and has practical application.

  15. 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)

  16. Comparisons of calculated respiratory tract deposition of particles based on the NCRP/ITRI model and the new ICRP66 model

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, Hsu-Chi; Phalen, R.F. [Univ. of California, Irvine, CA (United States); Chang, I. [Lovelace Inst., Albuquerque, NM (United States)] [and others

    1995-12-01

    The National Council on Radiation Protection and Measurements (NCRP) in the United States and the International Commission on Radiological Protection (ICRP) have been independently reviewing and revising respiratory tract dosimetry models for inhaled radioactive aerosols. The newly proposed NCRP respiratory tract dosimetry model represents a significant change in philosophy from the old ICRP Task Group model. The proposed NCRP model describes respiratory tract deposition, clearance, and dosimetry for radioactive substances inhaled by workers and the general public and is expected to be published soon. In support of the NCRP prop