A hydro-geochemical study of Nahr-Ibrahim catchment area: Fluvial metal transport

International Nuclear Information System (INIS)

Korfali, Samira

2004-01-01

Author.Metals enter water bodies geological weathering, soil erosion, industrial and domestic waste discharges, as well as atmospheric deposition. The metal content in sediments is a reflection of the nature of their background whether of geologic and/or anthropogenic origin. The depositional process of metals in sediment are controlled by river discharge, turbulence of river, morphology and river geometry, as well as the geochemical phases of sediment and soils. Thus a study of metal content in river and /or metal transport with a water body should include a hydrological study of the river, types of minerals in sediment and soil, sediment and soil textures, and metal speciation in the different geochemical phases of sediment, bank and soils. A contaminated flood plain is a temporary storage system for pollutants and an understanding of soil-sediment-interactions is important prerequisite for modeling fluvial pollutant transport. The determination of metal speciation in sediment and soil chemical fraction can provide information on the way in which these metals are bound to sediment and soil, their mobilization potential, bioavailability and possible mechanism of fluvial pollutant transport. Sequential extraction techniques yielding operationally defined chemical pools have been used by many workers to examine the partitioning of metals among the various geochemical phases of sediment or soil. The sequential extraction method specifies metals in sediment fractions as: exchangeable, specifically sorbed, easily reducible, moderately reducible, organic, residual. Previously, I have conducted a study on speciation of metals (Fe, Mn, Zn, Cu, Pb and Cd) in the dry season bed-load sediments only at five sites 13 km stretch upstream from the mouth of Nahr Ibrahim. The reported data revealed that the specifically sorbed sediment fraction was the prime fraction for deposition of Mn, Z, CU, Pb and Cd metals in sediments. X-ray diffraction analysis of bed sediments showed

Development of thermodynamically-based models for simulation of hydrogeochemical processes coupled to channel flow processes in abandoned underground mines

Energy Technology Data Exchange (ETDEWEB)

Kruse, N.A., E-mail: natalie.kruse@ncl.ac.uk [Sir Joseph Swan Institute for Energy Research, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom); Younger, P.L. [Sir Joseph Swan Institute for Energy Research, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom)

2009-07-15

Accurate modeling of changing geochemistry in mine water can be an important tool in post-mining site management. The Pollutant Sources and Sinks in Underground Mines (POSSUM) model and Pollutant Loadings Above Average Pyrite Influenced Geochemistry POSSUM (PLAYING POSSUM) model were developed using object-oriented programming techniques to simulate changing geochemistry in abandoned underground mines over time. The conceptual model was created to avoid significant simplifying assumptions that decrease the accuracy and defensibility of model solutions. POSSUM and PLAYING POSSUM solve for changes in flow rate and depth of flow using a finite difference hydrodynamics model then, subsequently, solve for geochemical changes at distinct points along the flow path. Geochemical changes are modeled based on a suite of 28 kinetically controlled mineral weathering reactions. Additional geochemical transformations due to reversible sorption, dissolution and precipitation of acid generating salts and mineral precipitation are also simulated using simplified expressions. Contaminant transport is simulated using a novel application of the Random-Walk method. By simulating hydrogeochemical changes with a physically and thermodynamically controlled model, the 'state of the art' in post-mining management can be advanced.

Predictive hydrogeochemical modelling of bauxite residue sand in field conditions.

Science.gov (United States)

Wissmeier, Laurin; Barry, David A; Phillips, Ian R

2011-07-15

The suitability of residue sand (the coarse fraction remaining from Bayer's process of bauxite refining) for constructing the surface cover of closed bauxite residue storage areas was investigated. Specifically, its properties as a medium for plant growth are of interest to ensure residue sand can support a sustainable ecosystem following site closure. The geochemical evolution of the residue sand under field conditions, its plant nutrient status and soil moisture retention were studied by integrated modelling of geochemical and hydrological processes. For the parameterization of mineral reactions, amounts and reaction kinetics of the mineral phases natron, calcite, tricalcium aluminate, sodalite, muscovite and analcime were derived from measured acid neutralization curves. The effective exchange capacity for ion adsorption was measured using three independent exchange methods. The geochemical model, which accounts for mineral reactions, cation exchange and activity corrected solution speciation, was formulated in the geochemical modelling framework PHREEQC, and partially validated in a saturated-flow column experiment. For the integration of variably saturated flow with multi-component solute transport in heterogeneous 2D domains, a coupling of PHREEQC with the multi-purpose finite-element solver COMSOL was established. The integrated hydrogeochemical model was applied to predict water availability and quality in a vertical flow lysimeter and a cover design for a storage facility using measured time series of rainfall and evaporation from southwest Western Australia. In both scenarios the sand was fertigated and gypsum-amended. Results show poor long-term retention of fertilizer ions and buffering of the pH around 10 for more than 5 y of leaching. It was concluded that fertigation, gypsum amendment and rainfall leaching alone were insufficient to render the geochemical conditions of residue sand suitable for optimal plant growth within the given timeframe. The

Assessing anthropogenic impact on boreal lakes with historical fish species distribution data and hydrogeochemical modeling.

Science.gov (United States)

Valinia, Salar; Englund, Göran; Moldan, Filip; Futter, Martyn N; Köhler, Stephan J; Bishop, Kevin; Fölster, Jens

2014-09-01

Quantifying the effects of human activity on the natural environment is dependent on credible estimates of reference conditions to define the state of the environment before the onset of adverse human impacts. In Europe, emission controls that aimed at restoring ecological status were based on hindcasts from process-based models or paleolimnological reconstructions. For instance, 1860 is used in Europe as the target for restoration from acidification concerning biological and chemical parameters. A more practical problem is that the historical states of ecosystems and their function cannot be observed directly. Therefore, we (i) compare estimates of acidification based on long-term observations of roach (Rutilus rutilus) populations with hindcast pH from the hydrogeochemical model MAGIC; (ii) discuss policy implications and possible scope for use of long-term archival data for assessing human impacts on the natural environment and (iii) present a novel conceptual model for interpreting the importance of physico-chemical and ecological deviations from reference conditions. Of the 85 lakes studied, 78 were coherently classified by both methods. In 1980, 28 lakes were classified as acidified with the MAGIC model, however, roach was present in 14 of these. In 2010, MAGIC predicted chemical recovery in 50% of the lakes, however roach only recolonized in five lakes after 1990, showing a lag between chemical and biological recovery. Our study is the first study of its kind to use long-term archival biological data in concert with hydrogeochemical modeling for regional assessments of anthropogenic acidification. Based on our results, we show how the conceptual model can be used to understand and prioritize management of physico-chemical and ecological effects of anthropogenic stressors on surface water quality. © 2014 The Authors Global Change Biology Published by John Wiley & Sons Ltd.

The Aespoe Hard Rock Laboratory: Final evaluation of the hydrogeochemical pre-investigations in relation to existing geologic and hydraulic conditions

International Nuclear Information System (INIS)

Smellie, J.; Laaksoharju, M.

1992-11-01

The Swedish Nuclear Fuel and Management Company (SKB) is currently excavating the access tunnel to an underground experimental laboratory, the Aespoe Hard Rock Laboratory, planned to be located some 500 m below the island of Aespoe which is located in the Simpevarp area, southeast Sweden. The construction of an underground laboratory forms part of the overall SKB strategy to test, not only the construction techniques for deep excavation, but also the various methods and protocols required to obtain a three-dimensional model of the geology and groundwater flow and chemistry, within a fractured crystalline bedrock similar to that envisaged for the final disposal of spent fuel. Aespoe was chosen because it geologically represents a variety of typical crystalline bedrock environments. The hydrogeochemical activities described and interpreted in this report form part of the initial pre-investigation phase (from the surface to around 1000 metres depth) aimed at siting the laboratory, describing the natural hydrogeological and hydrogeochemical conditions in the bedrock and predicting the changes that will occur during excavation and construction of the laboratory. Hydrogeochemical interpretation has therefore been closely integrated with the hydrogeological investigations and other disciplines of major influence, in particular, bedrock geology and geochemistry and fracture mineralogy and chemistry. A large section of this report has been devoted to the detailed investigation of each individual zone hydraulically selected, tested and sampled for hydrogeochemical characterization. The data have been used to describe the chemistry and origin of the Aespoe groundwaters, models have been developed to illustrate groundwater mixing and standard geochemical modelling approaches have been employed to understand rock/water interaction processes. An attempt has been made to integrate the hydrogeochemical information with known geological and hydrogeological parameters to construct a

Analysis of the Erosion Law of Karst Groundwater Using Hydrogeochemical Theory in Liulin Spring Area, North China

Directory of Open Access Journals (Sweden)

Xiuqing Zheng

2018-05-01

Full Text Available The comprehensive geological, hydrogeological and hydrogeochemical model of the Liulin karstic spring area in the eastern limb of the Ordos syncline was established by a combination of chemical thermodynamics, chemical kinetics and hydrogeology. The study area was divided into four zones based on the saturation indices of calcite, dolomite and gypsum, which were computed by the groundwater-chemical simulation software PHREEQC (a computer program for speciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations, with consideration of the geological and hydrogeological conditions and hydro-geochemical reactions. The weight and volume modulus of carbonate rocks and sulphate rocks in each zone were calculated by the method of correlation analysis to evaluate the dissolution law of karst groundwater. The results showed that in the zone I (saturation index of calcite βc ≤ 1 the dissolution of calcite was the major geochemical reaction, the weight modulus of calcite was higher than that of dolomite and gypsum, and the pore space generated by the dissolution of calcite was one order of magnitude larger than that of dolomite and gypsum. In zone II (saturation index of calcite βc > 1 to saturation index of dolomite βd ≤ 1 the corrosion moduli were all smaller than that in zone I, the solubility of dolomite and gypsum increased, and calcite reached saturation. The space occupied by the calcite sediment was less than that dissolved by dolomite and gypsum. In zone III (saturation index of dolomite βd > 1 to saturation index of gypsum βg ≤ 1, calcite and dolomite had reached saturation, accompanied by dedolomitization, and the amount of gypsum dissolution increased obviously. The conclusions indicate that the hydrogeochemical environment plays an important role in mineral dissolution.

Hydro-geochemical paths of multi-layer groundwater system in coal mining regions - Using multivariate statistics and geochemical modeling approaches.

Science.gov (United States)

Liu, Pu; Hoth, Nils; Drebenstedt, Carsten; Sun, Yajun; Xu, Zhimin

2017-12-01

Groundwater is an important drinking water resource that requires protection in North China. Coal mining industry in the area may influence the water quality evolution. To provide primary characterization of the hydrogeochemical processes and paths that control the water quality evolution, a complex multi-layer groundwater system in a coal mining area is investigated. Multivariate statistical methods involving hierarchical cluster analysis (HCA) and principal component analysis (PCA) are applied, 6 zones and 3 new principal components are classified as major reaction zones and reaction factors. By integrating HCA and PCA with hydrogeochemical correlations analysis, potential phases, reactions and connections between various zones are presented. Carbonates minerals, gypsum, clay minerals as well as atmosphere gases - CO 2 , H 2 O and NH 3 are recognized as major reactants. Mixtures, evaporation, dissolution/precipitation of minerals and cation exchange are potential reactions. Inverse modeling is finally used, and it verifies the detailed processes and diverse paths. Consequently, 4 major paths are found controlling the variations of groundwater chemical properties. Shallow and deep groundwater is connected primarily by the flow of deep groundwater up through fractures and faults into the shallow aquifers. Mining does not impact the underlying aquifers that represent the most critical groundwater resource. But controls should be taken to block the mixing processes from highly polluted mine water. The paper highlights the complex hydrogeochemical evolution of a multi-layer groundwater system under mining impact, which could be applied to further groundwater quality management in the study area, as well as most of the other coalfields in North China. Copyright © 2017 Elsevier B.V. All rights reserved.

Hydrogeochemical analysis for Tasuj plain aquifer, Iran

Indian Academy of Sciences (India)

This study investigated the hydrogeochemical processes of groundwater in the .... sis was also applied for investigating groundwater ... (Tasuj climatological station, 2000–2009) (Research .... location of the sample sites is shown in figure 1.

Hydrological and hydrogeochemical investigations in boreholes

International Nuclear Information System (INIS)

Carlsson, L.; Olsson, T.

1985-07-01

Underground investigations in boreholes are presumed to be an important investigation technique for the detailed design of a final repository for nuclear waste. The siting of the repository will be based on surface investigations, but for detailed investigations when the access shafts are sunk, investigations in underground boreholes from the initial shafts and tunnels will be of importance. The hydrogeological investigations in boreholes aimed at testing and developing of hydrogeological techniques and instruments for use in an underground environment in order to reflect actual working and testing conditions. This report is the final report from the hydrogeological investigations in boreholes, and it summarizes the different activities carried out during the course of the program. Most of the included activities are reported in separate internal reports, and therefore only the most important results are included, together with the experiences and conclusions gained during the investigations. The hydrogeochemical part of the program is in a separate final report, consequently no hydrogeochemical information is in the current report. (Author)

Evaluation of conceptual, mathematical and physical-and-chemical models for describing subsurface radionuclide transport at the Lake Karachai Waste Disposal Site

International Nuclear Information System (INIS)

Rumynin, V.G.; Mironenko, V.A.; Sindalovsky, L.N.; Boronina, A.V.; Konosavsky, P.K.; Pozdniakov, S.P.

1998-01-01

The goal of this work was to develop the methodology and to improve understanding of subsurface radionuclide transport for application to the Lake Karachai Site and to identify the influence of the processes and interactions involved into transport and fate of the radionuclides. The report is focused on two sets of problems, which have to do both with, hydrodynamic and hydrogeochemical aspects of the contaminant transport

Hydrogeochemical evaluation for Simpevarp model version 1.2. Preliminary site description of the Simpevarp area

Energy Technology Data Exchange (ETDEWEB)

Laaksoharju, Marcus (ed.) [Geopoint AB, Stockholm (Sweden)

2004-12-01

process. It controls chloride concentration that, in turn, determines the re-equilibrium path (water-rock interaction) triggered by mixing. Coupled transport modelling was used to model the groundwater age, tritium content and calcite dissolution/precipitation processes at shallow groundwater depths at both Laxemar and Simpevarp. The modelled results provide additional support to hydrogeological models by using independent hydrochemical information and added support to the general hydrogeochemical understanding of the site. In this evaluation the groundwater model has been updated, the salinity distribution, mixing processes and the major reactions altering the groundwaters have been modelled down to a depth of 1000 m, and an updated Hydrogeochemical Site Descriptive Model version 1.2 has been produced. More groundwater and isotopic data, together with microbial information, colloids and gases, provided additional site descriptive information. Finally, the introduction of coupled modelling provided additional possibilities to address independently the various processes in question.

Constraining groundwater flow model with geochemistry in the FUA and Cabril sites. Use in the ENRESA 2000 PA exercise

International Nuclear Information System (INIS)

Samper, J.; Carrera, J.; Bajos, C.; Astudillo, J.; Santiago, J.L.

1999-01-01

Hydrogeochemical activities have been a key factor for the verification and constraining of the groundwater flow model developed for the safety assessment of the FUA Uranium mill tailings restoration and the Cabril L/ILW disposal facility. The lesson learned in both sites will be applied to the ground water transport modelling in the current PA exercises (ENRESA 2000). The groundwater flow model in the Cabril site, represents a low permeability fractured media, and was performed using the TRANSIN code series developed by UPC-ENRESA. The hydrogeochemical data obtained from systematic yearly sampling and analysis campaigns were successfully applied to distinguish between local and regional flow and young and old groundwater. The salinity content, mainly the chlorine anion content, was the most critical hydrogeochemical data for constraining the groundwater flow model. (author)

Tritium tracing in hydrogeochemical studies using model-lysimeters

International Nuclear Information System (INIS)

Matthess, G.; Pekdeger, A.; Schulz, H.D.; Rast, H.; Rauert, W.

1978-01-01

Tritium was used as a reference tracer for hydrogeochemical studies in the unsaturated zone. The investigators used different lysimeter types (25, 50, 100 cm), with and without suction plates filled with undisturbed soil monoliths of sandy podsol and loamy lessive. The tritium loss was greater than the evaporation amount determined. Water logging takes place in lysimeter bottoms increasing the evaporation in up to 100 cm lysimeters filled with loamy lessive and 25 cm with sandy podsol. After a 20 mm rain event seepage characteristics indicate 'by-passing' water besides intergranular seepage. Dispersion coefficients (8.5 x 10 -5 cm 2 s -1 ) are higher than molecular diffusion coefficient. Dispersion takes place mainly in top soil with wide ranging pore size distribution. Distribution coefficients of tritium in soil are rather low. Concentrations of anions and dissolved organic substance are different depending on residence time of seepage water in soil. Even a short residence time of seepage water in unsaturated soil is enough for cation exchange reactions to take place. (orig.) [de

Hydrogeochemical evaluation of the Simpevarp area, model version 1.1

Energy Technology Data Exchange (ETDEWEB)

Laaksoharju, Marcus (ed.) [Geopoint AB, Stockholm (Sweden); Smellie, John [Conterra AB, Uppsala (Sweden); Gimeno, Maria; Auque, Luis; Gomez, Javier [Univ. of Zaragoza (Spain). Dept. of Earth Sciences; Tullborg, Eva-Lena [Terralogica AB, Graabo (Sweden); Gurban, Ioana [3D-Terra (Sweden)

2004-02-01

Siting studies for SKB's programme of deep geological disposal of nuclear fuel waste currently involves the investigation of two locations, Simpevarp and Forsmark, on the eastern coast of Sweden to determine their geological, hydrogeochemical and hydrogeological characteristics. Present work completed has resulted in model version 1.1 which represents the first evaluation of the available Simpevarp groundwater analytical data collected up to July 1st, 2003 (i.e. the first 'data freeze' of the site). The HAG (Hydrochemical Analytical Group) group had access to a total of 535 water samples collected from the surface and sub-surface environment (e.g. soil pipes in the overburden, streams and lakes); only a few samples were collected from drilled boreholes. The deepest fracture groundwater samples with sufficient analytical data reflected depths down to 250 m. Furthermore, most of the waters sampled (79%) lacked crucial analytical information that restricted the evaluation. Consequently, model version 1.1 focussed on the processes taking place in the uppermost part of the bedrock rather than at repository levels. The complex groundwater evolution and patterns at Simpevarp are a result of many factors such as: a) the flat topography and proximity to the Baltic Sea, b) changes in hydrogeology related to glaciation/deglaciation and land uplift, c) repeated marine/lake water regressions/transgressions, and d) organic or inorganic alteration of the groundwater composition caused by microbial processes or water/rock interactions. The sampled groundwaters reflect to various degrees of modern or ancient water/rock interactions and mixing processes. Higher topography to the west of Simpevarp has resulted in hydraulic gradients which have partially flushed out old water types. Except for sea waters, most surface waters and some groundwaters from percussion boreholes are fresh, non-saline waters according to the classification used for Aespoe groundwaters. The rest

Hydrogeochemical signatures and evolution of groundwater impacted by the Bayan Obo tailing pond in northwest China

Energy Technology Data Exchange (ETDEWEB)

Huang, Xiang [Institute of Water Sciences and College of Engineering, Peking University, Beijing (China); Shaanxi Key Laboratory of Comprehensive Utilization of Tailing Resources, Shangluo University, Shaanxi (China); Deng, Hailin, E-mail: hailin.deng@gmail.com [CSIRO Land and Water, Private Bag No. 5, Wembley, WA 6913 (Australia); Zheng, Chunmiao [Institute of Water Sciences and College of Engineering, Peking University, Beijing (China); School of Environmental Science and Engineering, South University of Science and Technology of China, Shenzhen (China); Department of Geological Science, University of Alabama, Tuscaloosa, AL (United States); Cao, Guoliang [Institute of Water Sciences and College of Engineering, Peking University, Beijing (China)

2016-02-01

Uncontrolled leakage from mine tailing ponds can pose a serious environmental threat. Groundwater quality in a semi-arid region with extensive worries about the leakage from one of world's largest tailing ponds is studied herein through an integrated hydrogeochemical analysis and multivariate statistical analysis. Results show that elevated concentrations of NO{sub 2}{sup −}, B, Mn, NH{sub 4}{sup +}, F{sup −}, and SO{sub 4}{sup 2−} in groundwater were probably caused by leakage from the tailing pond and transported with the regional groundwater flow towards downstream Yellow River. While NO{sub 2}{sup −} contamination is only limited to areas close to the pond, high B concentrations persist within the contaminated plume originating from the tailing pond. Our current study shows that there is no geochemical evidence for U and Th contamination in groundwater due to leakage from the Bayan Obo tailing pond. Combining effects which includes regional variations, pond leaking and downstream mixing, mineral precipitation and dissolution, redox processes, ion exchange processes and agricultural activities, controlled groundwater hydrogeochemical signatures in the studied area. This study demonstrate that an increase in knowledge of evolution of groundwater quality by integrating field hydrochemical data and multivariate statistical analysis will help understand major water–rock interactions and provide a scientific basis for protection and rational utilization of groundwater resources in this and other tailing-impacted areas. - Highlights: • Combining hydrogeochemical methods and multivariate statistical analysis. • First reporting geochemical processes in aquifers nearby Bayan Obo REE tailing pond. • No geochemical evidence for uranium and thorium contamination in shallow groundwater.

Preliminary Hydrogeochemical Site Description SFR (version 0.2)

Energy Technology Data Exchange (ETDEWEB)

Nilsson, Ann-Chatrin (Geosigma AB, Uppaala (Sweden)); Tullborg, Eva-Lena (Terralogica AB, Graabo (Sweden)); Smellie, John (Conterra AB, Partille (Sweden))

2010-05-15

The final repository for low and intermediate level radioactive operational waste, SFR, located about 150 km north of Stockholm, is to undergo a future extension. The present on-going project, scheduled from 2007 to 2011, is to define and characterise a suitable bedrock volume for the extended repository. This will include the drilling and geoscientific evaluation of seven core-drilled and four percussion boreholes as well as subsequent interpretation and modelling based on the obtained results in order to provide the necessary information for safety assessment and repository design. This report presents a preliminary hydrogeochemical site description for the SFR site and should be considered as an early progress report rather than a complete hydrochemical site descriptive model. The completed hydrogeochemical field investigations have yielded chemical data from a total of 12 borehole sections in five boreholes and additional data from the entire length of two open boreholes in connection with hydraulic tests. These data, together with data from a total of 18 early boreholes in the present SFR tunnel system, were used in the interpretation work. The main part of the data consisted of basic groundwater analyses including major ions and isotopes. Some sporadic gas, microbe and measured redox data are available, but these are either not treated in this report, or are only briefly discussed. This was due to time constraints since special care is needed when interpreting few data of varying quality. The groundwaters in the SFR dataset cover a maximum depth down to about .400 masl and represent a relatively limited salinity range (1,500 to 5,500 mg/L chloride). However, the delta18O values show a wide variation (-1.55 to -0.75% V-SMOW) similar to that reported from the Forsmark site investigations. At the SFR, marine indicators such as Mg/Cl, K/Cl and Br/Cl also show relatively large variations considering the limited salinity range. From very few measured Eh values, and

Preliminary Hydrogeochemical Site Description SFR (version 0.2)

International Nuclear Information System (INIS)

Nilsson, Ann-Chatrin; Tullborg, Eva-Lena; Smellie, John

2010-05-01

The final repository for low and intermediate level radioactive operational waste, SFR, located about 150 km north of Stockholm, is to undergo a future extension. The present on-going project, scheduled from 2007 to 2011, is to define and characterise a suitable bedrock volume for the extended repository. This will include the drilling and geoscientific evaluation of seven core-drilled and four percussion boreholes as well as subsequent interpretation and modelling based on the obtained results in order to provide the necessary information for safety assessment and repository design. This report presents a preliminary hydrogeochemical site description for the SFR site and should be considered as an early progress report rather than a complete hydrochemical site descriptive model. The completed hydrogeochemical field investigations have yielded chemical data from a total of 12 borehole sections in five boreholes and additional data from the entire length of two open boreholes in connection with hydraulic tests. These data, together with data from a total of 18 early boreholes in the present SFR tunnel system, were used in the interpretation work. The main part of the data consisted of basic groundwater analyses including major ions and isotopes. Some sporadic gas, microbe and measured redox data are available, but these are either not treated in this report, or are only briefly discussed. This was due to time constraints since special care is needed when interpreting few data of varying quality. The groundwaters in the SFR dataset cover a maximum depth down to about .400 masl and represent a relatively limited salinity range (1,500 to 5,500 mg/L chloride). However, the δ 18 O values show a wide variation (-1.55 to -0.75% V-SMOW) similar to that reported from the Forsmark site investigations. At the SFR, marine indicators such as Mg/Cl, K/Cl and Br/Cl also show relatively large variations considering the limited salinity range. From very few measured Eh values, and

Hydrogeochemical methods for studying uranium mineralization in sedimentary rocks

International Nuclear Information System (INIS)

Lisitsin, A.K.

1985-01-01

The role of hydrogeochemical studies of uranium deposits is considered, which permits to obtain data on ore forming role of water solutions. The hydrogeochemistry of ore formation is determined as a result of physicochemical analysis of mineral paragenesis. Analysis results of the content of primary and secondary gaseous - liquid inclusions into the minerals are of great importance. Another way to determine the main features of ore formation hydrogeochemistry envisages simultaneous analysis of material from a number of deposits of one genetic type but in different periods of their geochemical life: being formed, formed and preserved, and being destructed. Comparison of mineralogo-geochemical zonation and hydrogeochemical one in water-bearing horizon is an efficient method, resulting in the objective interpretation of the facts. The comparison is compulsory when determining deposit genesis

Hydrogeochemical and Isotopic Studies of Groundwater in the Central Region of Ghana

Energy Technology Data Exchange (ETDEWEB)

Ganyaglo, S. Y.; Osae, S.; Fianko, J.R., E-mail: sganyaglo@yahoo.co.uk [National Nuclear Research Institute, Ghana Atomic Energy Commission and School of Nuclear Allied Sciences, University of Ghana, Legon-Accra (Ghana); Gibrilla, A.; Bam, E. [National Nuclear Research Institute, Ghana Atomic Energy Commission, Legon-Accra (Ghana)

2013-07-15

The hydrogeochemical and isotopic evolution of groundwater in the Central Region of Ghana has been studied in order to examine how hydrogeochemical processes control the overall groundwater chemistry in the study area. Two major hydrochemical facies have been identified as the Na-Cl and NaHCO{sub 3} water types. The Na/Cl molar ratio indicates that silicate weathering is one of the major hydrogeochemical processes controlling groundwater water chemistry in the area. This is further confirmed by a plot of TDS against the Na/Na+Ca ratio. The Br/Cl ratio ranges from 0.00148 to 0.7087, suggesting minimal seawater intrusion in the area. Stable isotope values of the groundwater samples ({sup 18}O and {sup 2}H) are found around the global meteoric water line (GMWL), suggesting a direct infiltration of rainwater into the groundwater system. Elevated Cl- concentrations of the groundwater is probably due to sea spray and marine aerosols deposited on the top soil, though further studies are needed to determine the cause. (author)

Hydrogeochemical and stream sediment detailed geochemical survey for Edgemont, South Dakota; Wyoming

International Nuclear Information System (INIS)

1981-01-01

An area on the Long Mountain Structure Zone was chosen for examination of hydrogeochemical data. The data suggest the presence of a hydrogeochemical boundary approximately 5 to 7 km (3-1/2 to 4-1/2 mi) downdip of exposed mines and prospects in the Inyan Kara Group. Based on studies by Gatt, et al (1974) the hydrogeochemical boundary is interpreted to represent a zone of ion exchange favorable for precipitation of uranium. Updip of the boundary, the groundwater is of a calcium sulfate type. Uranium concentrations range from <0.2 to 32 ppB (mean = 13 ppB), calcium concentrations range from 85 to 320 ppB (mean = 158 ppB), and sulfate concentrations range from 600 to 1800 ppM (mean = 708 ppM). Sodium concentrations range from 43 to 363 ppM (mean = 168 ppM) and total alkalinity values range from 130 to 330 ppM (mean = 244 ppM). Downdip of the boundary, the groundwater is of a sodium bicarbonate type. Uranium concentrations range from < 0.2 to 0.54 ppB (mean = .28 ppB), calcium concentrations range from 1.0 to 45 ppB (mean = 8.4 ppB), and sulfate concentrations range from 41 to 1400 ppM (mean = 266 ppM). Sodium concentrations range from 176 to 744 ppM (mean = 296 ppM) and total alkalinity values range from 140 to 920 ppM (mean = 596 ppM). The maximum uranium value observed (32 ppB) occurs near the hydrogeochemical boundary

Conceptual model for regional radionuclide transport from a basalt repository site. Final draft, technical memorandum

International Nuclear Information System (INIS)

Walton, W.C.; Voorhees, M.L.; Prickett, T.A.

1980-01-01

This technical memorandum was prepared to: (1) describe a typical basalt radionuclide repository site, (2) describe geologic and hydrologic processes associated with regional radionuclide transport in basalts, (3) define the parameters required to model regional radionuclide transport from a basalt repository site, and (4) develop a ''conceptual model'' of radionuclide transport from a basalt repository site. In a general hydrological sense, basalts may be described as layered sequences of aquifers and aquitards. The Columbia River Basalt, centered near the semi-arid Pasco Basin, is considered by many to be typical basalt repository host rock. Detailed description of the flow system including flow velocities with high-low hydraulic conductivity sequences are not possible with existing data. However, according to theory, waste-transport routes are ultimately towards the Columbia River and the lengths of flow paths from the repository to the biosphere may be relatively short. There are many physical, chemical, thermal, and nuclear processes with associated parameters that together determine the possible pattern of radionuclide migration in basalts and surrounding formations. Brief process descriptions and associated parameter lists are provided. Emphasis has been placed on the use of the distribution coefficient in simulating ion exchange. The use of the distribution coefficient approach is limited because it takes into account only relatively fast mass transfer processes. In general, knowledge of hydrogeochemical processes is primitive

Conceptual model for regional radionuclide transport from a basalt repository site. Final draft, technical memorandum

Energy Technology Data Exchange (ETDEWEB)

Walton, W.C.; Voorhees, M.L.; Prickett, T.A.

1980-05-23

This technical memorandum was prepared to: (1) describe a typical basalt radionuclide repository site, (2) describe geologic and hydrologic processes associated with regional radionuclide transport in basalts, (3) define the parameters required to model regional radionuclide transport from a basalt repository site, and (4) develop a ''conceptual model'' of radionuclide transport from a basalt repository site. In a general hydrological sense, basalts may be described as layered sequences of aquifers and aquitards. The Columbia River Basalt, centered near the semi-arid Pasco Basin, is considered by many to be typical basalt repository host rock. Detailed description of the flow system including flow velocities with high-low hydraulic conductivity sequences are not possible with existing data. However, according to theory, waste-transport routes are ultimately towards the Columbia River and the lengths of flow paths from the repository to the biosphere may be relatively short. There are many physical, chemical, thermal, and nuclear processes with associated parameters that together determine the possible pattern of radionuclide migration in basalts and surrounding formations. Brief process descriptions and associated parameter lists are provided. Emphasis has been placed on the use of the distribution coefficient in simulating ion exchange. The use of the distribution coefficient approach is limited because it takes into account only relatively fast mass transfer processes. In general, knowledge of hydrogeochemical processes is primitive.

Geochemical tracing and hydrogeochemical modelling of water-rock interactions during salinization of alluvial groundwater (Upper Rhine Valley, France)

Energy Technology Data Exchange (ETDEWEB)

Lucas, Y., E-mail: yann.lucas@eost.u-strasbg.fr [Universite de Strasbourg et CNRS, Laboratoire d' Hydrologie et de Geochimie de Strasbourg, Ecole et Observatoire des Sciences de la Terre, 1, rue Blessig, 67084 Strasbourg Cedex (France); Schmitt, A.D., E-mail: anne-desiree.schmitt@univ-fcomte.fr [Universite de Strasbourg et CNRS, Laboratoire d' Hydrologie et de Geochimie de Strasbourg, Ecole et Observatoire des Sciences de la Terre, 1, rue Blessig, 67084 Strasbourg Cedex (France)] [Universite de Franche-Comte et CNRS-UMR 6249, Chrono-Environnement, 16, Route de Gray, 25030 Besancon Cedex (France); Chabaux, F., E-mail: francois.chabaux@eost.u-strasbg.fr [Universite de Strasbourg et CNRS, Laboratoire d' Hydrologie et de Geochimie de Strasbourg, Ecole et Observatoire des Sciences de la Terre, 1, rue Blessig, 67084 Strasbourg Cedex (France); Clement, A.; Fritz, B. [Universite de Strasbourg et CNRS, Laboratoire d' Hydrologie et de Geochimie de Strasbourg, Ecole et Observatoire des Sciences de la Terre, 1, rue Blessig, 67084 Strasbourg Cedex (France); Elsass, Ph. [BRGM, GEODERIS, 1, rue Claude Chappe, 57070 Metz (France); Durand, S. [Universite de Strasbourg et CNRS, Laboratoire d' Hydrologie et de Geochimie de Strasbourg, Ecole et Observatoire des Sciences de la Terre, 1, rue Blessig, 67084 Strasbourg Cedex (France)

2010-11-15

Research highlights: {yields} Major and trace elements along with strontium and uranium isotopic ratios show that groundwater geochemical characteristics along the saline plumes cannot reflect a conservative mixing. {yields} A coupled hydrogeochemical model demonstrates that cationic exchange between alkalis from polluted waters and alkaline-earth elements from montmorillonite present in the host rock of the aquifer is the primary process. {yields} The model requires only a small amount of montmorillonite. {yields} It is necessary to consider the pollution history to explain the important chloride, sodium and calcium concentration modifications. {yields} The model shows that the rapidity of the cationic exchange reactions insures a reversibility of the cation fixation on clays in the aquifer. - Abstract: In the southern Upper Rhine Valley, groundwater has undergone intensive saline pollution caused by the infiltration of mining brines, a consequence of potash extraction carried out during the 20th century. Major and trace elements along with Sr and U isotopic ratios show that groundwater geochemical characteristics along the saline plumes cannot reflect conservative mixing between saline waters resulting from the dissolution of waste heaps and one or more unpolluted end-members. The results imply the occurrence of interactions between host rocks and polluted waters, and they suggest that cationic exchange mechanisms are the primary controlling process. A coupled hydrogeochemical model has been developed with the numerical code KIRMAT, which demonstrates that cationic exchange between alkalis from polluted waters and alkaline-earth elements from montmorillonite present in the host rock of the aquifer is the primary process controlling the geochemical evolution of the groundwater. The model requires only a small amount of montmorillonite (between 0.75% and 2.25%), which is in agreement with the observed mineralogical composition of the aquifer. The model also proves

Factors affecting the distribution of hydrocarbon contaminants and hydrogeochemical parameters in a shallow sand aquifer

Science.gov (United States)

Lee, Jin-Yong; Cheon, Jeong-Yong; Lee, Kang-Kun; Lee, Seok-Young; Lee, Min-Hyo

2001-07-01

The distributions of hydrocarbon contaminants and hydrogeochemical parameters were investigated in a shallow sand aquifer highly contaminated with petroleum hydrocarbons leaked from solvent storage tanks. For these purposes, a variety of field investigations and studies were performed, which included installation of over 100 groundwater monitoring wells and piezometers at various depths, soil logging and analyses during well and piezometer installation, chemical analysis of groundwater, pump tests, and slug tests. Continuous water level monitoring at three selected wells using automatic data-logger and manual measuring at other wells were also conducted. Based on analyses of the various investigations and tests, a number of factors were identified to explain the distribution of the hydrocarbon contaminants and hydrogeochemical parameters. These factors include indigenous biodegradation, hydrostratigraphy, preliminary pump-and-treat remedy, recharge by rainfall, and subsequent water level fluctuation. The permeable sandy layer, in which the mean water table elevation is maintained, provided a dominant pathway for contaminant transport. The preliminary pump-and-treat action accelerated the movement of the hydrocarbon contaminants and affected the redox evolution pattern. Seasonal recharge by rain, together with indigenous biodegradation, played an important role in the natural attenuation of the petroleum hydrocarbons via mixing/dilution and biodegradation. The water level fluctuations redistributed the hydrocarbon contaminants by partitioning them into the soil and groundwater. The identified factors are not independent but closely inter-correlated.

Hydrogeochemical evaluation. Preliminary site description Laxemar subarea - version 1.2

International Nuclear Information System (INIS)

Laaksoharju, Marcus

2006-04-01

groups of groundwaters have been identified. Characterisation of pore water in core samples from the Laxemar borehole, KLX03, shows that chemical and isotopic pore water signatures have a characteristic variation of groundwater composition with rock type and depth that is in close agreement with the general trends in hydrochemistry of the adjacent formation (fracture) groundwaters. There is little apparent evidence of a glacial melt signature in the pore waters. Pore waters at depth show an affinity with deep brine evolution. Steady state conditions between pore water and formation groundwaters in the fractures are essentially only developed in the shallow zone of the Aevroe granite, while at depths greater than 450 m the chemical and isotopic composition of the pore water differs markedly from that of the fracture groundwaters in fractures. Diffusion between rock pore water and adjacent fracture groundwaters is identified as the dominant transport process; calculated diffusion coefficients agree well with current knowledge of conditions in the Laxemar site. In this report the models and the site understanding have been consolidated. Despite relatively few new data from depth, the models have been updated and the further understanding gained of groundwater origin, groundwater evolution, reactions, studies of interaction between shallow and deep groundwater, pore water composition in bedrock, microbial depth variation, uncertainties of the mixing calculations, tritium variations with time and 3D visualisation of the spatial variability of groundwater properties. An updated Hydrogeochemical Site Descriptive Model version 1.2 for Laxemar subarea has evolved. The resulting description has improved compared with the 1.2 version for Simpevarp subarea by producing a more detailed process modelling, uncertainty analysis and 3D visualisation. The microbial characterisation gives direct support to, for example, the redox modelling. The coupled transport modelling can address

Hydrogeochemical evaluation. Preliminary site description Laxemar subarea - version 1.2

Energy Technology Data Exchange (ETDEWEB)

Laaksoharju, Marcus (ed.) [Geopoint AB, Stockholm (Sweden)

2006-04-15

hydrochemical groups of groundwaters have been identified. Characterisation of pore water in core samples from the Laxemar borehole, KLX03, shows that chemical and isotopic pore water signatures have a characteristic variation of groundwater composition with rock type and depth that is in close agreement with the general trends in hydrochemistry of the adjacent formation (fracture) groundwaters. There is little apparent evidence of a glacial melt signature in the pore waters. Pore waters at depth show an affinity with deep brine evolution. Steady state conditions between pore water and formation groundwaters in the fractures are essentially only developed in the shallow zone of the Aevroe granite, while at depths greater than 450 m the chemical and isotopic composition of the pore water differs markedly from that of the fracture groundwaters in fractures. Diffusion between rock pore water and adjacent fracture groundwaters is identified as the dominant transport process; calculated diffusion coefficients agree well with current knowledge of conditions in the Laxemar site. In this report the models and the site understanding have been consolidated. Despite relatively few new data from depth, the models have been updated and the further understanding gained of groundwater origin, groundwater evolution, reactions, studies of interaction between shallow and deep groundwater, pore water composition in bedrock, microbial depth variation, uncertainties of the mixing calculations, tritium variations with time and 3D visualisation of the spatial variability of groundwater properties. An updated Hydrogeochemical Site Descriptive Model version 1.2 for Laxemar subarea has evolved. The resulting description has improved compared with the 1.2 version for Simpevarp subarea by producing a more detailed process modelling, uncertainty analysis and 3D visualisation. The microbial characterisation gives direct support to, for example, the redox modelling. The coupled transport modelling can

New insight into unstable hillslopes hydrology from hydrogeochemical modelling.

Science.gov (United States)

Bertrand, C.; Marc, V.; Malet, J.-P.

2010-05-01

In the black marl outcrops of the French South Alps, sub surface flow conditions are considered as the main triggering factor for initiation and reactivation of landslides. The problem is traditionally addressed in term of hydrological processes (how does percolation to the water table occur?) but in some cases the origin of water is also in question. Direct rainfall is generally assumed as the only water source for groundwater recharge in shallow hillslope aquifers. The bedrock is also supposed impervious and continuous. Yet the geological environment of the study area is very complex owing to the geological history of this alpine sector. The autochthonous callovo-oxfordian black marl bedrock is highly tectonized (Maquaire et al., 2003) and may be affected by large, possibly draining discontinuities. A deep water inflow at the slip surface may at least locally result in increase the pore pressure and decrease the effective shearing resistance of the landslide material. In the active slow-moving landslide of Super-Sauze (Malet and Maquaire, 2003), this question has been addressed using hydrochemical investigations. The groundwater was sampled during five field campaigns uniformly spread out over the year from a network of boreholes. Water chemistry data were completed by geochemical and mineralogical analyses of the marl material. The major hydro-geochemical processes over area proved (1) mixing processes, (2) pyrite alteration, (3) dissolution/precipitation of carbonates and (4) cations exchange (de Montety et al., 2007). A geochemical modelling was carried out using the model Phreeqc (Parkhurst and Appelo, version 2.15, 2008) to check how suitable was observed water chemistry with the reservoir characteristics. The modelling exercise was based on a kinetics approach of soil-water interactions. The model simulates the rock alteration by the dissolution of the primary minerals and the precipitation of new phases. Initial parameters were obtained from geochemical

Application of factor analysis in identification of dominant hydrogeochemical processes of some nitrogenous groundwater of Serbia

Directory of Open Access Journals (Sweden)

Stojković Jana

2013-01-01

Full Text Available Multivariate statistical analyses are used for reducing large datasets to a smaller number of variables, which explain main hydrogeochemical processes that control water geochemistry. Factor analysis (FA allows discovering intercorrelations inside the data matrix and grouping of similar variables, i.e. chemical parameters. In this way new variables are extracted, which are called factors, and each factor is explained by some hydrogeochemical process. Applying FA to a dataset that consists of 15 chemical parameters measured on 40 groundwater samples from Serbia, four factors were extracted, which explain 73.9% of total variance in the analyzed dataset. Interpretation of obtained factors indicated several hydrogeochemical processes: the impact of sea water intrusions and volatiles in previous geological periods, solutes diffusion from the marine clay, cation exchange and dissolution of carbonate and silicate minerals. [Projekat Ministarstva nauke Republike Srbije, br. 43004

Predictability of the evolution of hydrogeological and hydrogeochemical systems; geological disposal of nuclear waste in crystalline rocks

International Nuclear Information System (INIS)

Murphy, W.M.; Diodato, D.M.

2009-01-01

Confidence in long-term geologic isolation of high-level nuclear waste and spent nuclear fuel requires confidence in predictions of the evolution of hydrogeological and hydrogeochemical systems. Prediction of the evolution of hydrogeological and hydrogeochemical systems is based on scientific understanding of those systems in the present - an understanding that can be tested with data from the past. Crystalline rock settings that have been geologically stable for millions of years and longer offer the potential of predictable, long-term waste isolation. Confidence in predictions of geologic isolation of radioactive waste can measured by evaluating the extent to which those predictions and their underlying analyses are consistent with multiple independent lines of evidence identified in the geologic system being analysed, as well as with evidence identified in analogs to that geologic system. The proposed nuclear waste repository at Yucca Mountain, Nevada, United States, differs in significant ways from potential repository sites being considered by other nations. Nonetheless, observations of hydrogeological and hydrogeochemical systems of Yucca Mountain and Yucca Mountain analogs present multiple independent lines of evidence that can be used in evaluating long-term predictions of the evolution of hydrogeological and hydrogeochemical systems at Yucca Mountain. (authors)

HYDROGEOCHEMICAL CHARACTERISTICS OF THE ST. IVAN SPRING IN ISTRIA, CROATIA

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Tatjana Vlahović

2000-12-01

Full Text Available In addition to geological, hydrogeological investigations and groundwater tracing, detailed surveying of the groundwater quality is becoming particularly important for environmental impact monitoring on karst aquifers. Groundwater quality data contain two types of information i.e. the natural chemistry of water and its modifications caused by antropogenic impacts. The method of results presentation as well as the importance of water quality surveying particularly with respect to the indicators showing its natural chemistry, are shown here exemplified by the St. Ivan spring in Istria, Croatia. Natural chemistry of the groundwater is a consequence of hydrogeochemical facies, and it is used here for interpretation of spring generating conditions and the origin of groundwater. Results obtained so far confirm that the extent of recharge area of the spring change in dependence of the hydrological conditions. Hydrogeochemical characteristics of the spring are presented graphically in the form of correlation diagrams showing major groundwater parameters, saturation conditions and trends of particular parameters as a function of time.

Characterising flow regime and interrelation between surface-water and ground-water in the Fuente de Piedra salt lake basin by means of stable isotopes, hydrogeochemical and hydraulic data

Science.gov (United States)

Kohfahl, Claus; Rodriguez, Miguel; Fenk, Cord; Menz, Christian; Benavente, Jose; Hubberten, Hans; Meyer, Hanno; Paul, Liisa; Knappe, Andrea; López-Geta, Juan Antonio; Pekdeger, Asaf

2008-03-01

SummaryThis research reports the characterisation of ground- and surface-water interaction in the Fuente de Piedra Salt lake basin in southern Spain by a combined approach using hydraulic, hydrogeochemical and stable isotope data. During three sampling campaigns (February 2004, 2005 and October 2005) ground- and surface-water samples were collected for stable isotope studies ( 18O, D) and for major and minor ion analysis. Hydraulic measurements at multilevel piezometers were carried out at four different locations around the lake edge. Conductivity logs were performed at four piezometers located along a profile at the northern lake border and at two deeper piezometers in the Miocene basin at a greater distance from the lake. To describe processes that control the brine evolution different hydrogeochemical simulations were performed. Hydrogeochemical data show a variety of brines related to thickness variations of lacustrine evaporites around the lake. Salinity profiles in combination with stable isotope and hydraulic data indicate the existence of convection cells and recycled brines. Furthermore restricted ground-water inflow into the lake was detected. Dedolomitisation processes were identified by hydrogeochemical simulations and different brine origins were reproduced by inverse modelling approaches.

Water-rock interaction modelling and uncertainties of mixing modelling. SDM-Site Forsmark

Energy Technology Data Exchange (ETDEWEB)

Gimeno, Maria J.; Auque, Luis F.; Gomez, Javier B.; Acero, Patricia (Univ. of Zaragoza, Zaragoza (Spain))

2008-08-15

The overall objectives of the hydrogeochemical description for Forsmark are to establish a detailed understanding of the hydrogeochemical conditions at the site and to develop models that fulfil the needs identified by the safety assessment groups during the site investigation phase. Issues of concern to safety assessment are radionuclide transport and technical barrier behaviour, both of which are dependent on the chemistry of groundwater and pore water and their evolution with time. The work has involved the development of descriptive and mathematical models for groundwaters in relation to rock domains, fracture domains and deformation zones. Past climate changes are one of the major driving forces for hydrogeochemical changes and therefore of fundamental importance for understanding the palaeohydrogeological, palaeohydrogeochemical and present evolution of groundwater in the crystalline bedrock of the Fennoscandian Shield. Understanding current undisturbed hydrochemical conditions at the proposed repository site is important when predicting future changes in groundwater chemistry. The causes behind of copper corrosion and/or bentonite degradation are of particular interest as they may jeopardise the long-term integrity of the planned SKB repository system. Thus, the following variables are considered for the hydrogeochemical site descriptive modelling: pH, Eh, sulphur species, iron, manganese, carbonate, phosphate, nitrogen species, total dissolved solids (TDS), isotopes, colloids, fulvic and humic acids and microorganisms. In addition, dissolved gases (e.g. carbon dioxide, methane and hydrogen) are of interest because of their likely participation in microbial reactions. In this series of reports, the final hydrogeochemical evaluation work of the site investigation at the Forsmark site, is presented. The work was conducted by SKB's hydrogeochemical project group, ChemNet, which consists of independent consultants and university researchers with expertise

Water-rock interaction modelling and uncertainties of mixing modelling. SDM-Site Forsmark

International Nuclear Information System (INIS)

Gimeno, Maria J.; Auque, Luis F.; Gomez, Javier B.; Acero, Patricia

2008-08-01

The overall objectives of the hydrogeochemical description for Forsmark are to establish a detailed understanding of the hydrogeochemical conditions at the site and to develop models that fulfil the needs identified by the safety assessment groups during the site investigation phase. Issues of concern to safety assessment are radionuclide transport and technical barrier behaviour, both of which are dependent on the chemistry of groundwater and pore water and their evolution with time. The work has involved the development of descriptive and mathematical models for groundwaters in relation to rock domains, fracture domains and deformation zones. Past climate changes are one of the major driving forces for hydrogeochemical changes and therefore of fundamental importance for understanding the palaeohydrogeological, palaeohydrogeochemical and present evolution of groundwater in the crystalline bedrock of the Fennoscandian Shield. Understanding current undisturbed hydrochemical conditions at the proposed repository site is important when predicting future changes in groundwater chemistry. The causes behind of copper corrosion and/or bentonite degradation are of particular interest as they may jeopardise the long-term integrity of the planned SKB repository system. Thus, the following variables are considered for the hydrogeochemical site descriptive modelling: pH, Eh, sulphur species, iron, manganese, carbonate, phosphate, nitrogen species, total dissolved solids (TDS), isotopes, colloids, fulvic and humic acids and microorganisms. In addition, dissolved gases (e.g. carbon dioxide, methane and hydrogen) are of interest because of their likely participation in microbial reactions. In this series of reports, the final hydrogeochemical evaluation work of the site investigation at the Forsmark site, is presented. The work was conducted by SKB's hydrogeochemical project group, ChemNet, which consists of independent consultants and university researchers with expertise in

Hydrogeochemical and Isotopic Study of Groundwaters from the Gañuelas-Mazarrón Tertiary Basin (Murcia, Spain)

International Nuclear Information System (INIS)

Rodrigo-Naharro, J.; Delgado, A.; Clemente-Jul, C.; Pérez del Villar, L.

2015-01-01

The hydrogeochemical characterisation of groundwaters from the Gañuelas-Mazarrón Tertiary Basin included: i) to establish the different hydrofacies present in the basin; ii) to perform a cluster analysis in order to reduce the water samples, grouping them according to their physicochemical characteristics; and iii) to determine the most relevant ion ratios for understanding the water/ rock interaction processes that regulate the main features and evolution of groundwaters. It has also been discussed the origin and concentration of the minor and trace elements to evaluate the capability of groundwaters to transport heavy elements, toxic or innocuous, towards the surface, thus determining their suitability for human consumption. Besides, the hydrogeochemical modeling has allowed determining the degree of groundwaters saturation with respect to the most representative mineral phases of the aquifers, which, in turn, it has been used to calculate their theoretical temperature in depth. The isotopic characterisation of groundwaters has included the isotopic signatures of the stable (δ18O, δ2H, δ13C-DIC, δ34S(SO4 2-) and δ18O(SO4 2-)) and radioactive (238U, 234U and 226Ra) isotopes. The first have been used to distinguish the groundwaters origin, as well as the origin of the dissolved C and SO4 2-. The radioactive isotopes have been used to determine the water/rock interaction processes involving 238U radioactive series, as well as to explain the origin of the dissolved 222Rn in groundwaters. The most important hydrogeochemical results obtained from groundwaters are: i) a large variety of hydrofacies is represented in them, corroborated by the cluster analysis; ii) they are not suitable for human consumption; iii) they have remained, apparently, over-saturated with respect to calcite and aragonite, and under-saturated with respect to gypsum, anhydrite and halite, over time; iv) they present theoretical temperatures in depth much higher than in the surface; v) they

Hydrogeochemical radioactive features and prospecting in granopegmatite type uranium ore district in Danfeng area

International Nuclear Information System (INIS)

Feng Zhangsheng

2011-01-01

Hydrochemical radioactive prospecting plays an important role in the all stages of grano-pegmatite type uranium deposit exploration in Danfeng area dut to its fast, simple, economic and high effective advantage. Radioactive anomalous halo in the shallow underground water has identical distribution scopes with the ore-bearing biotite granite-pegmatite, which can be used to delineate uranium ore-forming prospective area, reconnaissance area and detailed prospecting area. Deep underground water close to the ore is characterized by hydrogeochemical radioactive features with high uranium and radon content. Through prospecting engineering of radioactive hydrogeochemical, the situation of blind ore bodies can be used to guide the layout. (authors)

Hydrogeochemical characteristics and bacterial community diversity in leachate from animal carcass disposal

Science.gov (United States)

Kaown, D.; Kim, H.; Lee, S.; Hyun, Y.; Moon, H.; Ko, K.; Lee, K.

2012-12-01

The release of leachate from animal carcass disposal can potentially contaminate soil and groundwater. During the Korea's foot-and-mouth disease (FMD) outbreak in 2010-2011, about 3.53 million of pigs and cattle were slaughtered and 4,538 burial sites were constructed. The objectives of this study are to determine the hydrogeochemical characteristics and bacterial community diversity in leachate from animal carcass disposal. Hydrogeochemical characteristics and bacterial community diversity in leachate from animal carcass burial facilities were monitored to prevent further soil and groundwater contamination and to build effective plans for stabilization of the burial site. Two burial sites were investigated in this study. An animal carcass disposal site is located in a flat area and another disposal site is found in mountain area. The hydrogeochemical and hydrogeological characteristics were analyzed to identify groundwater contamination by leachate from livestock burial sites. After 5-6 months of burial, the concentrations of NH4+, Cl-, and HCO3- in leachate were decreased since the leachate was regularly pumped and treated. However, high concentrations of major contaminants (NH4+, Cl-, and HCO3-) were still observed in landfill leachate of mountain area even though pumping and treatment of leachate were continuously conducted. Bacterial community diversity over time in leachate from animal carcass disposal was analyzed using 16S rRNA gene-based pyrosequencing. The impact of landfill leachate on change of bacterial community in soil and groundwater were monitored for a year.

Application of inverse modeling technique to describe hydrogeochemical processes responsible to spatial distribution of groundwater quality along flowpath

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Tjahyo NugrohoAdji

2013-07-01

The result shows that firstly, the aquifer within the research area can be grouped into several aquifer systems (i.e. denudational hill, colluvial plain, alluvial plain, and beach ridges from recharge to discharge which generally have potential groundwater resources in terms of the depth and fluctuation of groundwater table. Secondly, flownets analysis gives three flowpaths that are plausible to be modeled in order to describe their hydrogeochemical reactions. Thirdly, the Saturation Indices (SI analysis shows that there are a positive correlation between the mineral occurrence and composition and the value of SI from recharge to discharge. In addition, The Mass Balance Model indicates that dissolution and precipitation of aquifer minerals is dominantly change the chemical composition along flowpath and the rate of the mass transfer between two wells shows a discrepancy and be certain of the percentage of the nature of aquifer mineral. Lastly, there is an interesting characteristic of mass balance chemical reaction occurs which is the entire chemical reaction shows that the sum of smallest mineral fmmol/litre will firstly always totally be reacted.

The characteristics of hydrogeochemical zonation of groundwater in inland plain

Science.gov (United States)

Xin-yu, HOU; Li-ting, XING; Yi, YANG; Wen-jing, ZHANG; Guang-yao, CHI

2018-05-01

To find out the hydrochemical zoning of groundwaterin the inland plain, taking Jiyang plain as an example, based on mathematical statistics, ion ratio coefficient and isotopic analysis method, the characteristics of water chemical composition and its zoning at different depths of 500m were studied. The result shows: ①The groundwater flow system in the study area can be divided into local flow system, intermediate flow system and regional flow system. ②The hydrochemical type of shallow groundwater is complex. The hydrochemical types of middle confined water are mainly ClṡSO4—MgṡNa and SO4ṡCl—NaṡMg. The deep confined water is mainly HCO3. ③The TDS of shallow groundwater increases gradually along the direction of groundwater flow. ④The shallow saltwater and freshwater are alternately distributed in horizontal direction, and saltwater is distributed sporadically in the interfluve area with sporadic punctate or banded, and hydrochemical types are mainly ClṡSO4—NaṡMgṡCa. Conclusion: Groundwater in the study area is affected by complicated hydrogeochemical action, mainly in the form of filtration, cation exchange and evaporation. The inland plain area is characterized by hydrogeochemical zonation in horizontal and vertical.

Hydrogeochemical exploration for uranium in parts of Bhiwani district, Haryana, India - a preliminary study

International Nuclear Information System (INIS)

Pande, Dheeraj; Verma, A.K.; Srinivasan, S.; Bangroo, P.N.; Manjeet Kumar; Singh, Diwakar

1998-01-01

Hydrogeochemical exploration was carried out in the soil covered areas with isolated outcrops of metaquartzites of middle-Proterozoic Alwar group (Delhi supergroup) in parts of Bhiwani district of Haryana for identifying suitable locales for uranium mineralisation and also for establishing the sub-surface extensions of outcropping mineralisation. The preliminary evaluation of hydrogeochemical data indicates that the ground waters have dominantly surface water characteristics and are modified to some extent by agricultural fertilisers. Three hydrogeochemical anomalous zones, one each of uranium, uranium-vanadium and vanadium have been identified in the area. Anomalous content of uranium in the uranium zone is most likely to be due to very high sulphate content which may be a result of either heavy application of fertilisers or presence of gypsum-like horizons. The uranium-vanadium zone lies in close proximity to surface radiometric anomalies identified in the area and show little effect of agricultural contamination. The vanadium zone exhibits the least agricultural contamination and is related to ground waters of deeper origin. The uranium-vanadium and vanadium zones are found to be significant from the point of view of uranium mineralisation. The close association of uranium and vanadium in the area and the proximity of the uranium-vanadium zone to the surface radiometric anomalies suggest that the surface anomalies may have deeper extensions. (author)

Batch and column studies of adsorption of Li, Ni and Br by a reference sand for contaminant transport experiments

International Nuclear Information System (INIS)

Seigel, M.D.; Ward, D.B.; Bryan, C.R.

1995-09-01

A processed quartz sand (Wedron 510), mined from the St. Peter sandstone, has been characterized by a variety of chemical and physical methods for use as a reference porous media in transport model validation experiments. Wedron 510 sand was used in an intermediate-scale experiment involving migration of Ni, Li and Br through a 6-m high x 3-m diameter caisson. Ni and Li adsorption/desorption, and Li/Ni site-competition experiments yielded information on the importance of the trace mineral phases to adsorption of Li and Ni by the sand. The presence of an iron hydroxide coating similar to goethite on the sand grains is suggested by visual observation and leaching experiments. Kaolinite was identified by SEM and XRD as a significant trace mineral phase in the sand and occurs as small particles coating the sand grains. Quartz, the predominant constituent of the sand by weight, does not appear to contribute significantly to the adsorption properties of the sand. Qualitatively, the adsorption properties of the sand can be adequately modeled as a two-mineral system (goethite and kaolinite). The studies described in this report should provide a basis for understanding transport of Ni, Li and Br through porous media similar to the reference sand. Techniques were developed for obtaining parameter values for surface complexation and kinetic adsorption models for the sand and its mineral components. These constants can be used directly in coupled hydrogeochemical transport codes. The techniques should be useful for characterization of other natural materials and elements in high-level nuclear waste in support of coupled hydrogeochemical transport calculations for Yucca Mountain

Hydrogeochemical Modelling for Groundwater in Neyveli Aquifer, Tamil Nadu, India, Using PHREEQC: A Case Study

Energy Technology Data Exchange (ETDEWEB)

Chidambaram, S.; Anandhan, P. [Annamalai University, Department of Earth Sciences (India); Prasanna, M. V., E-mail: geoprasanna@gmail.com [Curtin University, Department of Applied Geology, School of Engineering and Science (Malaysia); Ramanathan, AL. [Jawaharlal Nehru University, School of Environmental Sciences (India); Srinivasamoorthy, K. [Pondicherry University, Department of Earth Sciences, School of Physical, Chemical and Applied Sciences (India); Senthil Kumar, G. [HNB Garwhal University, Department of Geology (India)

2012-09-15

Sophisticated geochemical models have been used to describe and predict the chemical behaviour of complex natural waters and also to protect the groundwater resources from future contamination. One such model is used to study the hydrogeochemical complexity in a mine area. Extraction of groundwater from the coastal aquifer has been in progress for decades to mine lignite in Neyveli. This extraction has developed a cone of depression around the mine site. This cone of depression is well established by the geochemical nature of groundwater in the region. 42 groundwater samples were collected in a definite pattern and they were analysed for major cations, anions and trace elements. The saturation index (SI) of the groundwater for carbonate, sulphate and silica minerals was studied and it has been correlated with the recharge and the discharge regions. The SI of alumino silicates has been used to decipher the stage of weathering. The SI{sub Gibbsite} - SI{sub K-feldspar} has been spatially distributed and the regions of discharge and recharge were identified. Then two flow paths A1 and A2 were identified and inverse modelling using PHREEQC were carried out to delineate the geochemical process that has taken place from recharge to discharge. The initial and final solutions in both the flow paths were correlated with the thermodynamic silicate stability diagrams of groundwater and it was found that the state of thermodynamic stability of the end solutions along the flow path were approaching similar states of equilibrium at the discharge.

Application of Environmental Isotope and Hydrogeochemical Techniques in Investigating the Geothermal Resources

International Nuclear Information System (INIS)

Kamarudin Samuding; Noor Akhmal Kamarudin; Mohd Shahrizal Mohamed Sharifodin; Azrul Arifin; Kamaruzaman Mohamad

2016-01-01

An investigation of geothermal resources at Ulu Slim has been carried out using integrated environmental isotope and hydro-geochemical techniques. Environmental isotope Oxygen-18 ("1"8O) and Deuterium ("2H) and Tritium ("3H) were used to identify the recharge zones and origin of the water, whereas the hydro-geochemical technique is used to determine the water type and the level of solutes in the geothermal waters out flowing at the surface as well as in shallow and deep groundwater system. The sampling programme includes precipitations, surface waters, hot springs, groundwater for isotopes and hydro-geochemical analyses. The plot graph of (δ"1"8O vs δ"2H) show that the stable isotope composition of hot spring is relatively depleted as compared to surface water and groundwater. This indicates that the recharge of the hot spring is likely to occur from farther and higher elevation areas of the geothermal system. Tritium content in hot spring, groundwater and surface water is ranged between 0.85 - 0.92 TU, 0.81- 1.05 TU, 1.60-2.07 TU respectively. The values of TU in hot spring and groundwater is seen similar suggests that these samples are older than the surface water. Based on the plot of Ternary Major Anion diagram (Cl-SO_4- HCO_3) and Tri-linear Piper diagram, all the water samples are identified from the type of bicarbonate (HCO_3). Nevertheless, the content of sodium (Na) in hot spring is detected relatively higher as compared to surface water. Tri-linear Piper diagram also shows that there is no mixing process between hot spring and surface water. (author)

Task force on modelling of groundwater flow and transport of solutes. Task 5 Summary report

International Nuclear Information System (INIS)

Rhen, Ingvar; Smellie, John

2003-02-01

The Aespoe Hard Rock Laboratory is located in the Simpevarp area, southeast Sweden, some 35 km north of Oskarshamn. Construction of the underground laboratory commenced in 1990 and was completed in 1995, consisting of a 3.6 km. long tunnel excavated in crystalline rock to a depth of approximately 460 m. Prior to, during and subsequent to completion, research concerning the deep geological disposal of nuclear waste in fractured crystalline rock has been carried out. Central to this research has been the characterisation of the groundwater flow system and the chemistry of the groundwaters at Aespoe prior to excavation (Pre-investigation Phase) and subsequently to monitor changes in these parameters during the evolution of laboratory construction (Construction Phase). The principle aim of the Aespoe Task 5 modelling exercise has been to compare and ultimately integrate hydrogeochemistry and hydrogeology using the input data from the pre-investigation and construction phases. The main objectives were: to assess the consistency of groundwater-flow models and hydrogeochemical mixing-reaction models through integration and comparison of hydraulic and hydrogeochemical data obtained before and during tunnel construction, and to develop a procedure for integration of hydrological and hydrogeochemical information which could be used for disposal site assessments. Task 5 commenced in 1998 and was finalised in 2002. Participating modelling teams in the project represented ANDRA (France; three modelling teams - ANTEA, ITASCA, CEA), BMWi/BGR (Germany), ENRESA (Spain), JNC (Japan), CRIEPI (Japan), Posiva (Finland) and SKB (Sweden; two modelling teams - CFE and Intera (now GeoPoint)). Experience from Task 5 has highlighted several important aspects for site investigations facilitating the possibilities for mathematically integrated modelling and consistency checks that should be taken into account for future repository performance assessments. Equally important is that Task 5 has

Task force on modelling of groundwater flow and transport of solutes. Task 5 Summary report

Energy Technology Data Exchange (ETDEWEB)

Rhen, Ingvar [SWECO VIAK AB, Goeteborg (Sweden); Smellie, John [Conterra AB, Uppsala (Sweden)

2003-02-01

The Aespoe Hard Rock Laboratory is located in the Simpevarp area, southeast Sweden, some 35 km north of Oskarshamn. Construction of the underground laboratory commenced in 1990 and was completed in 1995, consisting of a 3.6 km. long tunnel excavated in crystalline rock to a depth of approximately 460 m. Prior to, during and subsequent to completion, research concerning the deep geological disposal of nuclear waste in fractured crystalline rock has been carried out. Central to this research has been the characterisation of the groundwater flow system and the chemistry of the groundwaters at Aespoe prior to excavation (Pre-investigation Phase) and subsequently to monitor changes in these parameters during the evolution of laboratory construction (Construction Phase). The principle aim of the Aespoe Task 5 modelling exercise has been to compare and ultimately integrate hydrogeochemistry and hydrogeology using the input data from the pre-investigation and construction phases. The main objectives were: to assess the consistency of groundwater-flow models and hydrogeochemical mixing-reaction models through integration and comparison of hydraulic and hydrogeochemical data obtained before and during tunnel construction, and to develop a procedure for integration of hydrological and hydrogeochemical information which could be used for disposal site assessments. Task 5 commenced in 1998 and was finalised in 2002. Participating modelling teams in the project represented ANDRA (France; three modelling teams - ANTEA, ITASCA, CEA), BMWi/BGR (Germany), ENRESA (Spain), JNC (Japan), CRIEPI (Japan), Posiva (Finland) and SKB (Sweden; two modelling teams - CFE and Intera (now GeoPoint)). Experience from Task 5 has highlighted several important aspects for site investigations facilitating the possibilities for mathematically integrated modelling and consistency checks that should be taken into account for future repository performance assessments. Equally important is that Task 5 has

A fission track technique used for hydrogeochemical prospecting in Northern India

International Nuclear Information System (INIS)

Singh, N.P.; Singh, S.; Virk, H.S.

1988-01-01

A fission track technique is employed to determine the uranium content of water samples collected from different locations of the middle and outer Himalayas. The regional threshold for the uranium content is determined for water samples of different areas. The identification of anomalies in an area of uranium mineralization confirmed that the hydrogeochemical technique could successfully be used for uranium exploration. (author)

Groundwater flow and hydrogeochemical evolution in the Jianghan Plain, central China

Science.gov (United States)

Gan, Yiqun; Zhao, Ke; Deng, Yamin; Liang, Xing; Ma, Teng; Wang, Yanxin

2018-05-01

Hydrogeochemical analysis and multivariate statistics were applied to identify flow patterns and major processes controlling the hydrogeochemistry of groundwater in the Jianghan Plain, which is located in central Yangtze River Basin (central China) and characterized by intensive surface-water/groundwater interaction. Although HCO3-Ca-(Mg) type water predominated in the study area, the 457 (21 surface water and 436 groundwater) samples were effectively classified into five clusters by hierarchical cluster analysis. The hydrochemical variations among these clusters were governed by three factors from factor analysis. Major components (e.g., Ca, Mg and HCO3) in surface water and groundwater originated from carbonate and silicate weathering (factor 1). Redox conditions (factor 2) influenced the geogenic Fe and As contamination in shallow confined groundwater. Anthropogenic activities (factor 3) primarily caused high levels of Cl and SO4 in surface water and phreatic groundwater. Furthermore, the factor score 1 of samples in the shallow confined aquifer gradually increased along the flow paths. This study demonstrates that enhanced information on hydrochemistry in complex groundwater flow systems, by multivariate statistical methods, improves the understanding of groundwater flow and hydrogeochemical evolution due to natural and anthropogenic impacts.

Integration and consistency testing of groundwater flow models with hydro-geochemistry in site investigations in Finland

International Nuclear Information System (INIS)

Pitkaenen, P.; Loefman, J.; Korkealaakso, J.; Koskinen, L.; Ruotsalainen, P.; Hautojaervi, A.; Aeikaes, T.

1999-01-01

In the assessment of the suitability and safety of a geological repository for radioactive waste the understanding of the fluid flow at a site is essential. In order to build confidence in the assessment of the hydrogeological performance of a site in various conditions, integration of hydrological and hydrogeochemical methods and studies provides the primary method for investigating the evolution that has taken place in the past, and for predicting future conditions at the potential disposal site. A systematic geochemical sampling campaign was started since the beginning of 1990's in the Finnish site investigation programme. This enabled the initiating of integration and evaluation of site scale hydrogeochemical and groundwater flow models. Hydrogeochemical information has been used to screen relevant external processes and variables for definition of the initial and boundary conditions in hydrological simulations. The results obtained from interpretation and modelling hydrogeochemical evolution have been employed in testing the hydrogeochemical consistency of conceptual flow models. Integration and testing of flow models with hydrogeochemical information are considered to improve significantly the hydrogeological understanding of a site and increases confidence in conceptual hydrogeological models. (author)

Modelling freight transport

NARCIS (Netherlands)

Tavasszy, L.A.; Jong, G. de

2014-01-01

Freight Transport Modelling is a unique new reference book that provides insight into the state-of-the-art of freight modelling. Focusing on models used to support public transport policy analysis, Freight Transport Modelling systematically introduces the latest freight transport modelling

Review of the analytical techniques used in the hydrogeochemical prospecting of uranium

International Nuclear Information System (INIS)

Grimbert, A.; Berthollet, P.

1959-01-01

This report examines the methods recommended for the estimation of uranium in water. The advantages and disadvantages of these methods are studied with respect to the qualities necessary for the hydrogeochemical prospecting of uranium sensitivity of the order of 1/5 ppb with an accuracy of 15 to 20 per cent, high fidelity, rapidity, simplicity and low cost. (author) [fr

Hydrogeological and Hydrogeochemical Modelling of the Alicun de las Torres Termal System (Province of Granada). Isotope Hydrochemistry and Gases in Groundwaters

International Nuclear Information System (INIS)

Prado Perez, A. J.; Delgado, A.; Crespo, M. T.; Martin, A.; Vaselli, O.; Perez del Villar, L.

2010-01-01

In the framework of a Singular Strategic Project entitled: A dvanced Technologies of Carbon, Capture and Storage (CCS) , supported by the MICINN (Spain) and the FEDER founds (EU), specifically in the Carbon Storage Task, a comprehensive study on the CO 2 leakage as DIC (Dissolved Inorganic Carbon) in the Alicun de Las Torres (Prov. of Granada) natural analogue thermal system was envisaged. This analogous system is characterised by the presence of a very important travertine formation, which can be considered as a permanent and stable sink for CO 2 . In order to explain the formation of these travertine mass an hydrogeological and hydrogeochemical model of the area has been established by using the hydrochemical data, the stable and radioactive isotope characteristics, the dissolved inorganic carbon, as well as the chemical and isotopic composition of the free and dissolved gases of the above mentioned Thermal System. (Author) 11 refs.

Water-rock interaction modelling and uncertainties of mixing modelling. SDM-Site Laxemar

International Nuclear Information System (INIS)

Gimeno, Maria J.; Auque, Luis F.; Gomez, Javier B.; Acero, Patricia

2009-01-01

The overall objectives of hydrogeochemical description for Laxemar are to establish a detailed understanding of the hydrogeochemical conditions at the site and to develop models that fulfil the needs identified by the safety assessment groups during the site investigation phase. Issues of concern to safety assessment are radionuclide transport and technical barrier behaviour, both of which are dependent on the chemistry of groundwater and pore water and their evolution with time. The work has involved the development of descriptive and mathematical models for groundwaters in relation to rock domains, fracture domains and deformation zones. Past climate changes are the major driving force for hydrogeochemical changes and therefore of fundamental importance for understanding the palaeohydrogeological, palaeohydrogeochemical and present evolution of groundwater in the crystalline bedrock of the Fennoscandian Shield. Understanding current undisturbed hydrochemical conditions at the proposed repository site is important when predicting future changes in groundwater chemistry. The causes of copper corrosion and/or bentonite degradation are of particular interest as they may jeopardise the long-term integrity of the planned SKB repository system. Thus, the following variables are considered for the hydrogeochemical site descriptive modelling: pH, Eh, sulphur species, iron, manganese, carbonate, phosphate, nitrogen species, total dissolved solids (TDS), isotopes, colloids, fulvic and humic acids and microorganisms. In addition, dissolved gases (e.g. carbon dioxide, methane and hydrogen) are of interest because of their likely participation in microbial reactions. In this series of reports, the final hydrogeochemical evaluation work of the site investigation at the Laxemar site, is presented. The work was conducted by SKB's hydrogeochemical project group, ChemNet, which consists of independent consultants and Univ. researchers with expertise in geochemistry, hydrochemistry

Water-rock interaction modelling and uncertainties of mixing modelling. SDM-Site Laxemar

Energy Technology Data Exchange (ETDEWEB)

Gimeno, Maria J.; Auque, Luis F.; Gomez, Javier B.; Acero, Patricia (Univ. of Zaragoza, Zaragoza (Spain))

2009-01-15

The overall objectives of hydrogeochemical description for Laxemar are to establish a detailed understanding of the hydrogeochemical conditions at the site and to develop models that fulfil the needs identified by the safety assessment groups during the site investigation phase. Issues of concern to safety assessment are radionuclide transport and technical barrier behaviour, both of which are dependent on the chemistry of groundwater and pore water and their evolution with time. The work has involved the development of descriptive and mathematical models for groundwaters in relation to rock domains, fracture domains and deformation zones. Past climate changes are the major driving force for hydrogeochemical changes and therefore of fundamental importance for understanding the palaeohydrogeological, palaeohydrogeochemical and present evolution of groundwater in the crystalline bedrock of the Fennoscandian Shield. Understanding current undisturbed hydrochemical conditions at the proposed repository site is important when predicting future changes in groundwater chemistry. The causes of copper corrosion and/or bentonite degradation are of particular interest as they may jeopardise the long-term integrity of the planned SKB repository system. Thus, the following variables are considered for the hydrogeochemical site descriptive modelling: pH, Eh, sulphur species, iron, manganese, carbonate, phosphate, nitrogen species, total dissolved solids (TDS), isotopes, colloids, fulvic and humic acids and microorganisms. In addition, dissolved gases (e.g. carbon dioxide, methane and hydrogen) are of interest because of their likely participation in microbial reactions. In this series of reports, the final hydrogeochemical evaluation work of the site investigation at the Laxemar site, is presented. The work was conducted by SKB's hydrogeochemical project group, ChemNet, which consists of independent consultants and Univ. researchers with expertise in geochemistry

Bedrock hydrogeochemistry Forsmark. Site descriptive modelling SDM-Site Forsmark

Energy Technology Data Exchange (ETDEWEB)

Laaksoharju, Marcus [Geopoint AB, Sollentuna (Sweden); Smellie, John [Conterra AB, Partille (Sweden); Tullborg, Eva-Lena [Terralogica, Graabo (Sweden); Gimeno, Maria [Univ. of Zaragoza, Zaragoza (Spain); Hallbeck, Lotta [Microbial Analytics, Goeteborg (Sweden); Molinero, Jorge [Amphos XXI Consulting S.L., Barcelona (Spain); Waber, Nick [Univ. of Bern, Bern (Switzerland)

2008-12-15

The overall objectives of the hydrogeochemical site description for Forsmark are to establish a detailed understanding of the hydrogeochemical conditions at the site, and to use this understanding to develop models that address the needs identified by the safety assessment groups during the site investigation phase. Issues of concern to safety assessment are radionuclide transport and technical barrier behaviour, both of which are dependent on the chemistry of groundwater and porewater and their evolution with time. The specific aims of the hydrogeochemical work were: To document the hydrogeochemistry at the Forsmark site with focus on the development of conceptual models to describe and visualise the site. To provide relevant parameter values to be used for safety assessment calculations. To provide the hydrogeochemical basis for the modelling work by other teams, in particular hydrogeology. To take account of the feedback from the SR-Can safety assessment work that bears relevance to the hydrogeochemical modelling work. The work has involved the development of descriptive and mathematical models for groundwaters in relation to rock domains, fracture domains and deformation zones. In this report, the groundwaters have been interpreted in relation to their origin, evolution and composition, which require close integration with geological, climatological and hydrogeological information. Past climate changes are one of the major driving forces for long-term hydrogeochemical changes (hundreds to thousands of years) and are, therefore, of fundamental importance for understanding the palaeohydrogeological, palaeohydrogeochemical and present evolution of groundwater in the Fennoscandian crystalline bedrock. In contrast, redox buffer capacity of the bedrock will minimise the effects on changes in alkalinity and redox at repository depths, therefore limiting the variations in pH and Eh significantly, regardless of major changes in groundwater composition. There is

Bedrock hydrogeochemistry Forsmark. Site descriptive modelling SDM-Site Forsmark

International Nuclear Information System (INIS)

Laaksoharju, Marcus; Smellie, John; Tullborg, Eva-Lena; Gimeno, Maria; Hallbeck, Lotta; Molinero, Jorge; Waber, Nick

2008-12-01

The overall objectives of the hydrogeochemical site description for Forsmark are to establish a detailed understanding of the hydrogeochemical conditions at the site, and to use this understanding to develop models that address the needs identified by the safety assessment groups during the site investigation phase. Issues of concern to safety assessment are radionuclide transport and technical barrier behaviour, both of which are dependent on the chemistry of groundwater and porewater and their evolution with time. The specific aims of the hydrogeochemical work were: To document the hydrogeochemistry at the Forsmark site with focus on the development of conceptual models to describe and visualise the site. To provide relevant parameter values to be used for safety assessment calculations. To provide the hydrogeochemical basis for the modelling work by other teams, in particular hydrogeology. To take account of the feedback from the SR-Can safety assessment work that bears relevance to the hydrogeochemical modelling work. The work has involved the development of descriptive and mathematical models for groundwaters in relation to rock domains, fracture domains and deformation zones. In this report, the groundwaters have been interpreted in relation to their origin, evolution and composition, which require close integration with geological, climatological and hydrogeological information. Past climate changes are one of the major driving forces for long-term hydrogeochemical changes (hundreds to thousands of years) and are, therefore, of fundamental importance for understanding the palaeohydrogeological, palaeohydrogeochemical and present evolution of groundwater in the Fennoscandian crystalline bedrock. In contrast, redox buffer capacity of the bedrock will minimise the effects on changes in alkalinity and redox at repository depths, therefore limiting the variations in pH and Eh significantly, regardless of major changes in groundwater composition. There is

Hydrogeochemical evaluation of the Forsmark site, model version 1.1

Energy Technology Data Exchange (ETDEWEB)

Laaksoharju, Marcus (ed.) [GeoPoint AB, Sollentuna (Sweden); Gimeno, Maria; Auque, Luis; Gomez, Javier [Univ. of Zaragoza (Spain). Dept. of Earth Sciences; Smellie, John [Conterra AB, Uppsala (Sweden); Tullborg, Eva-Lena [Terralogica AB, Graabo (Sweden); Gurban, Ioana [3D-Terra, Montreal (Canada)

2004-01-01

values below detection limit). The meteoric water is found at the surface and at shallow depths and the marine water is found closer to the coast and at depths affected by Baltic Sea water and probably old Litorina Sea water. The present state of knowledge of the reactive system is that the main water-rock interaction processes that affects the chemistry in the fresh meteoric waters are: 1) decomposition of organic matter, 2) calcite, plagioclase, biotite and sulphide dissolution, 3) Na-Ca ion exchange, and 4) phyllosilicate precipitation probably extremely slow in the present environment. For the brackish-saline groundwaters in contrast, the water/rock interaction processes seem to be less important although this has not been established because of a lack of data. At the moment multiple end-member mixing between marine water, glacial melt water and a deeper saline water seem to play a significant role. Based on presently available data, the groundwater sample at 115 m depth, i.e. not representative of repository depths, met the groundwater criterion established by SKB concerning the measured Eh, pH, TDS and Ca+Mg values. The redox system at this depth is controlled by the presence of iron oxides, hydroxides or by sulphide minerals. In this evaluation the post glacial groundwater scenario model has been updated, the salinity distribution, mixing processes and the major reactions altering the groundwaters have been modelled down to a depth of 200 m and a new Hydrogeochemical Site Descriptive Model version 1.1 has been produced. A 3D groundwater description of the site was not produced at this stage due to a lack of observations reflecting spatial variations. The possibilities to compare and integrate future hydrochemical modelling with hydrogeological modelling has improved due to major development in constructing hydrogeological site models. The salinity distribution in fractures and the rock matrix together with mixing proportions can be compared from two independent

Sample collection: an overview of the Hydrogeochemical and Stream Sediment Reconnaissance Program

International Nuclear Information System (INIS)

Bolivar, S.L.

1979-01-01

A Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) for uranium is currently being conducted throughout the conterminous United States and Alaska. The HSSR is part of the National Uranium Resource Evaluation sponsored by the US Department of Energy. This ambitious geochemical reconnaissance program is conducted by four national laboratories: Los Alamos Scientific Laboratory, Lawrence Livermore Laboratory, Oak Ridge Gaseous Diffusion Plant, and Savannah River Laboratory. The program is based on an extensive review of world literature, reconnaissance work done in other countries, and pilot studies conducted by each laboratory. Sample-collection methods and sample density are determined to optimize the probability of detecting potential uranium mineralization. To achieve this aim, each laboratory has developed independent standardized field collection procedures that are designed for its section of the country. Field parameters such as pH, conductivity, climate, geography, and geology are recorded at each site. Most samples are collected at densities of one sample site per 10 to 23 km 2 . The HSSR program has helped to improve existing hydrogeochemical reconnaissance exploration techniques. In addition to providing industry with data that may help to identify potential uranium districts and to extend known uranium provinces, the HSSR also provides multi-element analytical data, which can be used in water quality, soil, sediment, environmental, and base-metal exploration studies

One hundred prime references on hydrogeochemical and stream sediment surveying for uranium as internationally practiced, including 60 annotated references

International Nuclear Information System (INIS)

Sharp, R.R. Jr.; Bolivar, S.L.

1981-04-01

The United States Department of Energy (DOE), formerly the US ERDA, has initiated a nationwide Hydrogeochemical and Stream Sediment Reconnaissance (HSSR). This program is part of the US National Uranium Resource Evaluation, designed to provide an improved estimate for the availability and economics of nuclear fuel resources and make available to industry information for use in exploration and development of uranium resources. The Los Alamos National Laboratory is responsible for completing the HSSR in Rocky Mountain states of New Mexico, Colorado, Wyoming, and Montana and in the state of Alaska. This report contains a compilation of 100 prime references on uranium hydrogeochemical and stream sediment reconnaissance as internationally practiced prior to 1977. The major emphasis in selection of these references was directed toward constructing a HSSR program with the purpose of identifying uranium in the Los Alamos National Laboratory area of responsibility. The context of the annotated abstracts are the authors' concept of what the respective article contains relative to uranium geochemistry and hydrogeochemical and stream sediment surveying. Consequently, in many cases, significant portions of the original articles are not discussed. The text consists of two parts. Part I contains 100 prime references, alphabetically arranged. Part II contains 60 select annotated abstracts, listed in chronological order

Hydrogeochemical and stream-sediment reconnaissance program at LLL

International Nuclear Information System (INIS)

Tinney, J.F.

1977-03-01

The Lawrence Livermore Laboratory (LLL) is conducting a Hydrogeochemical and Stream-Sediment Reconnaissance (HSSR) survey in support of ERDA's National Uranium Resource Evaluation (NURE) program. Included in the LLL portion of this survey are seven western states (Arizona, California, Idaho, Nevada, Oregon, Utah, and Washington). Similar surveys are being carried out in the rest of the continental United States, including Alaska, as part of a systematic nationwide study of the distribution of uranium in surface water, groundwater, and stream sediment. The overall objective is to identify favorable areas for uranium exploration. This paper describes the program being conducted by LLL to complete our portion of the survey by 1981. The topics discussed are geology and sample acquisition, sample preparation and analysis, and data-base management

Influence of Humic Acid on the Transport and Deposition of Colloidal Silica under Different Hydrogeochemical Conditions

Directory of Open Access Journals (Sweden)

Jingjing Zhou

2016-12-01

Full Text Available The transport and deposition of colloids in aquifers plays an important role in managed aquifer recharge (MAR schemes. Here, the processes of colloidal silica transport and deposition were studied by displacing groundwater with recharge water. The results showed that significant amounts of colloidal silica transport occurred when native groundwater was displaced by HA solution. Solution contains varying conditions of ionic strength and ion valence. The presence of humic acid could affect the zeta potential and size of the colloidal silica, which led to obvious colloidal silica aggregation in the divalent ion solution. Humic acid increased colloidal silica transport by formation of non-adsorbing aqueous phase silica–HA complexes. The experimental and modeling results showed good agreement, indicating that the essential physics were accurately captured by the model. The deposition rates were less than 10−8 s−1 in deionized water and monovalent ion solution. Moreover, the addition of Ca2+ and increase of IS resulted in the deposition rates increasing by five orders of magnitude to 10−4 s−1. In all experiments, the deposition rates decreased in the presence of humic acid. Overall, the promotion of humic acid in colloidal silica was strongly associated with changes in water quality, indicating that they should receive greater attention during MAR.

Data management and analysis systems for large-scale hydrogeochemical reconnaissance

International Nuclear Information System (INIS)

Ferguson, R.B.; Maddox, J.H.; Wren, H.F.

1976-01-01

The Savannah River Laboratory has developed a versatile, computerized data recording, processing, updating, and retrieval system for handling an expected 150 million bytes of hydrogeochemical data from 150,000 to 200,000 sample sites over the next four years. A sub-system accounts for the movements of samples from initial receipt through final storage. Approximately 6 million sample movements are expected. Two- and three-dimensional plots of sampled geographic areas showing concentrations and locations of individual chemical elements are displayed and reproduced photographically. Pattern recognition techniques enable multivariate data to be categorized into ''clusters'' which indicate sites favorable for uranium exploration

Advanced transport modeling of toroidal plasmas with transport barriers

International Nuclear Information System (INIS)

Fukuyama, A.; Murakami, S.; Honda, M.; Izumi, Y.; Yagi, M.; Nakajima, N.; Nakamura, Y.; Ozeki, T.

2005-01-01

Transport modeling of toroidal plasmas is one of the most important issue to predict time evolution of burning plasmas and to develop control schemes in reactor plasmas. In order to describe the plasma rotation and rapid transition self-consistently, we have developed an advanced scheme of transport modeling based on dynamical transport equation and applied it to the analysis of transport barrier formation. First we propose a new transport model and examine its behavior by the use of conventional diffusive transport equation. This model includes the electrostatic toroidal ITG mode and the electromagnetic ballooning mode and successfully describes the formation of internal transport barriers. Then the dynamical transport equation is introduced to describe the plasma rotation and the radial electric field self-consistently. The formation of edge transport barriers is systematically studied and compared with experimental observations. The possibility of kinetic transport modeling in velocity space is also examined. Finally the modular structure of integrated modeling code for tokamaks and helical systems is discussed. (author)

Hydrogeochemical Evolution of the Laxemar Site

Energy Technology Data Exchange (ETDEWEB)

Gimeno, Maria J.; Auque, Luis F.; Gomez, Javier B. (Univ. of Zaragoza (Spain)); Salas, Joaquin; Molinero, Jorge (Amphos 21, Barcelona (Spain))

2010-11-15

induce changes in the geochemical composition of groundwater around the repository. In this way, the present report summarizes the results obtained by the geochemical simulations performed to simulate the hydrogeochemical evolution of groundwaters in the Laxemar area. In the safety assessment of the candidate repository site, a series of functions and parameters must be evaluated. From a geochemical point of view, the most important are redox properties, pH and concentration of solutes. Other factors to be considered are the groundwater content of potassium, sulphide and iron, as they might affect the chemical stability of the buffer and the canister. Additionally, the effects of grouting in the geosphere and cement materials in the engineered barriers could affect groundwater's pH. Discussions of the results will be focused on these aspects. The starting point of the geochemical calculations is a series of hydrological models (using ConnectFlow and DarcyTools), which, based on the understanding of the palaeohydrogeological history of the sites (which assumes the presence of different water mixing events due to the input of different reference waters over the time), have provided information on (1) the transport of fractions of selected reference waters (deep saline, old meteoric, glacial, marine and present meteoric waters), in the case of the temperate period, or (2) the transport of salts, in the case of the glacial cycle. In the latter case, the rock volume initially contains a mixture of two reference waters: a deep saline groundwater and a dilute water from meteoric origin. The proportion of these two waters can be obtained from the salinity at any point in the rock volume. With the advancement and retreat of the glacier, the proportion of a third mixing end-member is calculated from the decrease of salinity at any point in the rock volume (a newly incoming glacial melt-water), changing the proportions of the other two reference waters correspondingly. Finally

Hydrogeochemical Evolution of the Laxemar Site

International Nuclear Information System (INIS)

Gimeno, Maria J.; Auque, Luis F.; Gomez, Javier B.; Salas, Joaquin; Molinero, Jorge

2010-11-01

induce changes in the geochemical composition of groundwater around the repository. In this way, the present report summarizes the results obtained by the geochemical simulations performed to simulate the hydrogeochemical evolution of groundwaters in the Laxemar area. In the safety assessment of the candidate repository site, a series of functions and parameters must be evaluated. From a geochemical point of view, the most important are redox properties, pH and concentration of solutes. Other factors to be considered are the groundwater content of potassium, sulphide and iron, as they might affect the chemical stability of the buffer and the canister. Additionally, the effects of grouting in the geosphere and cement materials in the engineered barriers could affect groundwater's pH. Discussions of the results will be focused on these aspects. The starting point of the geochemical calculations is a series of hydrological models (using ConnectFlow and DarcyTools), which, based on the understanding of the palaeohydrogeological history of the sites (which assumes the presence of different water mixing events due to the input of different reference waters over the time), have provided information on (1) the transport of fractions of selected reference waters (deep saline, old meteoric, glacial, marine and present meteoric waters), in the case of the temperate period, or (2) the transport of salts, in the case of the glacial cycle. In the latter case, the rock volume initially contains a mixture of two reference waters: a deep saline groundwater and a dilute water from meteoric origin. The proportion of these two waters can be obtained from the salinity at any point in the rock volume. With the advancement and retreat of the glacier, the proportion of a third mixing end-member is calculated from the decrease of salinity at any point in the rock volume (a newly incoming glacial melt-water), changing the proportions of the other two reference waters correspondingly. Finally

Application of factor analysis to the hydrogeochemical study of a coastal aquifer

OpenAIRE

Ruiz Beviá, Francisco; Gomis Yagües, Vicente; Blasco Alemany, Pilar

1989-01-01

The use of numerical values for the chemical components of waters from an aquifer as input data for factor analysis is shown to be sometimes more convenient than the use of the logarithms of these figures. Factor analysis was applied to the hydrogeochemical study of a coastal aquifer located in Javea, Alicante (Spain). A set of factors was found which explained the source of the ions in the water and even certain chemical processes which accompany the intrusion of seawater, such as the strong...

Hydrogeochemical and spectroscopic studies of radioactive materials in Ayrakan and Cheshmeh Shotori areas, northeastern Isfahan province

Directory of Open Access Journals (Sweden)

Mostafa Esmaeili Vardanjani

2011-11-01

Full Text Available Groundwaters hydrochemistry of Ayrakan and Cheshmeh Shotori areas and geochemistry of rare earth elements, indicate Ayrakan alkali granite as the origin of uranium and other dissolved elements in groundwaters of these areas. Geochemical and hydrogeochemical studies as well as the trend of uranium and thorium transition and mobility in aqueous environments of these areas indicate uranium adsorption by iron hydroxide (goethite as the deterrent agent against uranium transition and mobility from depth to surface. Gamma-ray spectroscopic study of sediments from Cheshmeh Shotori area by HPGe detector indicates the presence of 226Ra in high contents and as the radioactive nuclide that is the reason for high activity of these sediments. Production of 226Ra from 238U decay, shorter half-life of 226Ra compared to 238U, radium transition by groundwaters from depth to surface as well as hydrogeochemical evidences, all suggest the possibility of existence of hidden uranium deposit and uranium mineralization in depth and the distance between Ayrakan and Cheshmeh Shotori areas.

UZ Colloid Transport Model

International Nuclear Information System (INIS)

McGraw, M.

2000-01-01

The UZ Colloid Transport model development plan states that the objective of this Analysis/Model Report (AMR) is to document the development of a model for simulating unsaturated colloid transport. This objective includes the following: (1) use of a process level model to evaluate the potential mechanisms for colloid transport at Yucca Mountain; (2) Provide ranges of parameters for significant colloid transport processes to Performance Assessment (PA) for the unsaturated zone (UZ); (3) Provide a basis for development of an abstracted model for use in PA calculations

Overview of the National Uranium Resource Evaluation Hydrogeochemical and Stream Sediment Reconnaissance Program

International Nuclear Information System (INIS)

Bolivar, S.L.

1980-01-01

A Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) for uranium is currently being conducted throughout the conterminous United States and Alaska. The HSSR is part of the National Uranium Resource Evaluation sponsored by the US Department of Energy. This ambitious geochemical reconnaissance program is conducted by four Department of Energy laboratories: Los Alamos Scientific Laboratory, Lawrence Livermore Laboratory, Oak Ridge Gaseous Diffusion Plant, and Savannah River Laboratory. The program is based on an extensive review of world literature, reconnaissance work done in other countries, and pilot studies conducted by each laboratory. Sample-collection methods and sample density are determined to optimize the probability of detecting potential uranium mineralization. To achieve this aim, each laboratory has developed independent standardized field collection procedures that are designed for its section of the country. Field parameters such as pH, conductivity, climate, geography, and geology are recorded at each site. Most areas are sampled at densities of one sample site per 10 to 23 km 2 . The HSSR program has helped to improve existing hydrogeochemical reconnaissance exploration techniques. In addition to providing industry with data that may help to identify potential uranium districts and to extend known uranium provinces, the HSSR also provides multielement analytical data that can be used in water quality, soil, sediment, environmental, and base-metal exploration studies

Overview of the National Uranium Resource Evaluation Hydrogeochemical and Stream Sediment Reconnaissance Program

International Nuclear Information System (INIS)

Bolivar, S.L.

1980-07-01

A Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) for uranium is currently being conducted throughout the conterminous United States and Alaska. The HSSR is part of the National Uranium Resource Evaluation sponsored by the US Department of Energy. This ambitious geochemical reconnasissance program is conducted by four Department of Energy Laboratories: Los Alamos Scientific Laboratory, Lawrence Livermore Laboratory, Oak Ridge Gaseous Diffusion Plant, and Savannah River Laboratory. Each laboratory was assigned a geographic region of the United States. The program is based on an extensive review of world literature, reconnaissance work done in other countries, and pilot studies conducted by each laboratory. Sample-collection methods and sample density are determined to optimize the probability of detecting potential uranium mineralization. To achieve this aim, each laboratory has developed independent standardized field collection procedures that are designed for its section of the country. Field parameters such as pH, conductivity, climate, geography, and geology are recorded at each site. Most areas are sampled at densities of one sample site per 10 to 23 km 2 . The HSSR program has helped to improve existing hydrogeochemical reconnaissance exploration techniques. In addition to providing industry with data that may help to identify potential uranium districts and to extend known uranium provinces, the HSSR also provides multielement analytical data that can be used in water quality, soil, sediment, environmental, and base-metal exploration studies

A Process-Based Transport-Distance Model of Aeolian Transport

Science.gov (United States)

Naylor, A. K.; Okin, G.; Wainwright, J.; Parsons, A. J.

2017-12-01

We present a new approach to modeling aeolian transport based on transport distance. Particle fluxes are based on statistical probabilities of particle detachment and distributions of transport lengths, which are functions of particle size classes. A computational saltation model is used to simulate transport distances over a variety of sizes. These are fit to an exponential distribution, which has the advantages of computational economy, concordance with current field measurements, and a meaningful relationship to theoretical assumptions about mean and median particle transport distance. This novel approach includes particle-particle interactions, which are important for sustaining aeolian transport and dust emission. Results from this model are compared with results from both bulk- and particle-sized-specific transport equations as well as empirical wind tunnel studies. The transport-distance approach has been successfully used for hydraulic processes, and extending this methodology from hydraulic to aeolian transport opens up the possibility of modeling joint transport by wind and water using consistent physics. Particularly in nutrient-limited environments, modeling the joint action of aeolian and hydraulic transport is essential for understanding the spatial distribution of biomass across landscapes and how it responds to climatic variability and change.

Hydrogeochemical evaluation. Preliminary site description Forsmark area - version 1.2

International Nuclear Information System (INIS)

Laaksoharju, Marcus

2005-03-01

Siting studies for SKB's programme of deep geological disposal of nuclear fuel waste currently involves the investigation of two locations, Forsmark and Laxemar-Simpevarp, on the eastern coast of Sweden to determine their geological, hydrogeochemical and hydrogeological characteristics. Present work completed has resulted in Model version 1.2 which represents the second evaluation of the available Forsmark groundwater analytical data collected up to June, 2004. The Hydrochemical Analytical Group (HAG) had access to data where a total of 1,131 water samples had been collected from the surface and sub-surface environment; 252 samples were collected from drilled boreholes. The deepest fracture groundwater samples with sufficient analytical data reflected depths down to 1 km. Most of the waters sampled (66%) lacked crucial analytical information that restricted the evaluation. Model version 1.2 focuses on geochemical and mixing processes affecting the groundwater composition in the uppermost part of the bedrock, down to repository levels, and eventually extending to 1,000 m depth. The complex groundwater evolution and patterns at Forsmark are a result of many factors such as: a) the present-day topography and proximity to the Baltic Sea, b) past changes in hydrogeology related to glaciation/deglaciation, land uplift and repeated marine/lake water regressions/ transgressions, and c) organic or inorganic alteration of the groundwater composition caused by microbial processes or water/rock interactions. The sampled groundwaters reflect to various degrees processes relating to modern or ancient water/rock interactions and mixing. The groundwater flow regimes at Forsmark are considered local and extend down to depths of around 600 m depending on hydraulic conditions. Close to the Baltic Sea coastline where topographical variation is even less, groundwater flow penetration to depth will subsequently be less marked and such areas will tend to be characterised by groundwater

Hydrogeochemical evaluation. Preliminary site description Forsmark area - version 1.2

Energy Technology Data Exchange (ETDEWEB)

Laaksoharju, Marcus (ed.) [Geopoint AB, Stockholm (Sweden)

2005-03-15

Siting studies for SKB's programme of deep geological disposal of nuclear fuel waste currently involves the investigation of two locations, Forsmark and Laxemar-Simpevarp, on the eastern coast of Sweden to determine their geological, hydrogeochemical and hydrogeological characteristics. Present work completed has resulted in Model version 1.2 which represents the second evaluation of the available Forsmark groundwater analytical data collected up to June, 2004. The Hydrochemical Analytical Group (HAG) had access to data where a total of 1,131 water samples had been collected from the surface and sub-surface environment; 252 samples were collected from drilled boreholes. The deepest fracture groundwater samples with sufficient analytical data reflected depths down to 1 km. Most of the waters sampled (66%) lacked crucial analytical information that restricted the evaluation. Model version 1.2 focuses on geochemical and mixing processes affecting the groundwater composition in the uppermost part of the bedrock, down to repository levels, and eventually extending to 1,000 m depth. The complex groundwater evolution and patterns at Forsmark are a result of many factors such as: a) the present-day topography and proximity to the Baltic Sea, b) past changes in hydrogeology related to glaciation/deglaciation, land uplift and repeated marine/lake water regressions/ transgressions, and c) organic or inorganic alteration of the groundwater composition caused by microbial processes or water/rock interactions. The sampled groundwaters reflect to various degrees processes relating to modern or ancient water/rock interactions and mixing. The groundwater flow regimes at Forsmark are considered local and extend down to depths of around 600 m depending on hydraulic conditions. Close to the Baltic Sea coastline where topographical variation is even less, groundwater flow penetration to depth will subsequently be less marked and such areas will tend to be characterised by

Explorative analysis of major components and isotopes. SDM-Site Forsmark

Energy Technology Data Exchange (ETDEWEB)

Smellie, John (Conterra AB (Sweden)); Tullborg, Eva-Lena (Terralogica AB (Sweden)); Nilsson, Ann-Chatrin (Geosigma AB (Sweden)); Sandstroem, Bjoern (Goeteborg Univ. (Sweden)); Waber, Niklaus (Univ. of Bern (Switzerland)); Gimeno, Maria (Univ. of Zaragoza (Spain)); Gascoyne, Mel (GGP Inc. (United Kingdom))

2008-09-15

The overall objectives of the hydrogeochemical description for Forsmark are to establish a detailed understanding of the hydrogeochemical conditions at the site and to develop models that fulfil the needs identified by the safety assessment groups during the site investigation phase. Issues of concern to safety assessment are radionuclide transport and technical barrier behaviour, both of which are dependent on the chemistry of groundwater and pore water and their evolution with time. The work has involved the development of descriptive and mathematical models for groundwaters in relation to rock domains, fracture domains and deformation zones. Past climate events are the major driving force for hydrogeochemical changes and therefore are of fundamental importance for understanding the palaeohydrogeological, palaeohydrogeochemical and present evolution of groundwater in the crystalline bedrock of the Fennoscandian Shield. Understanding current undisturbed hydrochemical conditions at the proposed repository site is important when predicting future changes in groundwater chemistry. The causes behind copper corrosion and/or bentonite degradation are of particular interest as they may jeopardise the long-term integrity of the planned SKB repository system. Thus, the following variables are considered for the hydrogeochemical site descriptive modelling: pH, Eh, sulphur species, iron, manganese, carbonate, phosphate, nitrogen species, total dissolved solids (TDS), isotopes, colloids, fulvic and humic acids and microorganisms. In addition, dissolved gases (e.g. carbon dioxide, methane and hydrogen) are of interest because of their likely participation in microbial reactions. In this series of reports, the final hydrogeochemical evaluation work of the site investigation at the Forsmark site, is presented. The work was conducted by SKB's hydrogeochemical project group, ChemNet, which consists of independent consultants and university researchers with expertise in

Explorative analysis of major components and isotopes. SDM-Site Forsmark

International Nuclear Information System (INIS)

Smellie, John; Tullborg, Eva-Lena; Nilsson, Ann-Chatrin; Sandstroem, Bjoern; Waber, Niklaus; Gimeno, Maria; Gascoyne, Mel

2008-09-01

The overall objectives of the hydrogeochemical description for Forsmark are to establish a detailed understanding of the hydrogeochemical conditions at the site and to develop models that fulfil the needs identified by the safety assessment groups during the site investigation phase. Issues of concern to safety assessment are radionuclide transport and technical barrier behaviour, both of which are dependent on the chemistry of groundwater and pore water and their evolution with time. The work has involved the development of descriptive and mathematical models for groundwaters in relation to rock domains, fracture domains and deformation zones. Past climate events are the major driving force for hydrogeochemical changes and therefore are of fundamental importance for understanding the palaeohydrogeological, palaeohydrogeochemical and present evolution of groundwater in the crystalline bedrock of the Fennoscandian Shield. Understanding current undisturbed hydrochemical conditions at the proposed repository site is important when predicting future changes in groundwater chemistry. The causes behind copper corrosion and/or bentonite degradation are of particular interest as they may jeopardise the long-term integrity of the planned SKB repository system. Thus, the following variables are considered for the hydrogeochemical site descriptive modelling: pH, Eh, sulphur species, iron, manganese, carbonate, phosphate, nitrogen species, total dissolved solids (TDS), isotopes, colloids, fulvic and humic acids and microorganisms. In addition, dissolved gases (e.g. carbon dioxide, methane and hydrogen) are of interest because of their likely participation in microbial reactions. In this series of reports, the final hydrogeochemical evaluation work of the site investigation at the Forsmark site, is presented. The work was conducted by SKB's hydrogeochemical project group, ChemNet, which consists of independent consultants and university researchers with expertise in

Investigations in hydrogeochemical samples for uranium exploration

International Nuclear Information System (INIS)

Krishnakumar, M.

2015-01-01

The primary mandate of Atomic Minerals Directorate for Exploration and Research (AMD) is to explore and establish the uranium and other atomic mineral resources required for the country's nuclear power programme. During the geochemical exploration, a large number of ground, surface, spring, stream and lake water samples are collected and analysed for various parameters. These include physical parameters such as temperature, pH, Eh, electrical conductivity etc., and concentrations of uranium and multi-ions at mg/L to ng/L using state-of-the-art instrumental analytical techniques. Hydrogeochemical analysis is considered to be a cost effective and rapid exploration tool for getting sub-surface information leading to finding of concealed uranium deposits. Water samples from a bore well, dug well, stream, spring which is in dynamic equilibrium with the rocks are collected in a white, thick walled, non-transparent, non-recycled and air-tight container, stored and analysed within eight hours if possible to avoid change in Eh-pH conditions and precipitation-dissolution of trace elements

Groundwater Mixing Process Identification in Deep Mines Based on Hydrogeochemical Property Analysis

Directory of Open Access Journals (Sweden)

Bo Liu

2016-12-01

Full Text Available Karst collapse columns, as a potential water passageway for mine water inrush, are always considered a critical problem for the development of deep mining techniques. This study aims to identify the mixing process of groundwater deriving two different limestone karst-fissure aquifer systems. Based on analysis of mining groundwater hydrogeochemical properties, hydraulic connection between the karst-fissure objective aquifer systems was revealed. In this paper, piper diagram was used to calculate the mixing ratios at different sampling points in the aquifer systems, and PHREEQC Interactive model (Version 2.5, USGS, Reston, VA, USA, 2001 was applied to modify the mixing ratios and model the water–rock interactions during the mixing processes. The analysis results show that the highest mixing ratio is 0.905 in the C12 borehole that is located nearest to the #2 karst collapse column, and the mixing ratio decreases with the increase of the distance from the #2 karst collapse column. It demonstrated that groundwater of the two aquifers mixed through the passage of #2 karst collapse column. As a result, the proposed Piper-PHREEQC based method can provide accurate identification of karst collapse columns’ water conductivity, and can be applied to practical applications.

Development of cloud point extraction - UV-visible spectrophotometric method for vanadium (V) determination in hydrogeochemical samples

International Nuclear Information System (INIS)

Durani, Smeer; Mathur, Neerja; Chowdary, G.S.

2007-01-01

The cloud point extraction behavior (CPE) of vanadium (V) using 5,7 dibromo 8-hydroxyquinoline (DBHQ) and triton X 100 was investigated. Vanadium (V) was extracted with 4 ml of 0.5 mg/ml DBHQ and 6 ml of 8% (V/V) triton X 100 at the pH 3.7. A few hydrogeochemical samples were analysed for vanadium using the above method. (author)

Geochemical modelling study on the age and evolution of the groundwater at the Romuvaara site

International Nuclear Information System (INIS)

Pitkaenen, P.; Vuorinen, U.; Leino-Forsman, H.; Snellman, M.

1996-09-01

The objective of the study was to interpret the processes and factors which control the hydrogeochemistry (e.g. pH and redox conditions) in the radioactive waste disposal environment. A model of the hydrogeochemical evolution and the chemical flowpaths in different parts of the bedrock at the Romuvaara (in Finland) site has been created. The significance of chemical reactions along different flowpaths is calculated. Furthermore, the consistency of the hydrogeochemical model and the hydrogeological model is examined. (107 refs.)

Geochemical modelling study on the age and evolution of the groundwater at the Romuvaara site

Energy Technology Data Exchange (ETDEWEB)

Pitkaenen, P; Vuorinen, U; Leino-Forsman, H [Technical Research Centre of Finland, Espoo (Finland); Snellman, M [Imatran Voima Oy, Helsinki (Finland)

1996-09-01

The objective of the study was to interpret the processes and factors which control the hydrogeochemistry (e.g. pH and redox conditions) in the radioactive waste disposal environment. A model of the hydrogeochemical evolution and the chemical flowpaths in different parts of the bedrock at the Romuvaara (in Finland) site has been created. The significance of chemical reactions along different flowpaths is calculated. Furthermore, the consistency of the hydrogeochemical model and the hydrogeological model is examined. (107 refs.).

Provenance and fate of arsenic and other solutes in the Chaco-Pampean Plain of the Andean foreland, Argentina: From perspectives of hydrogeochemical modeling and regional tectonic setting

Science.gov (United States)

Raychowdhury, Nilasree; Mukherjee, Abhijit; Bhattacharya, Prosun; Johannesson, Karen; Bundschuh, Jochen; Sifuentes, Gabriela Bejarano; Nordberg, Erika; Martin, Raúl A.; Storniolo, Angel del Rosario

2014-10-01

Extensive arsenic (As) enriched groundwater is known to occur in the aquifers of the Chaco-Pampean Plain of Argentina. Previous studies speculated that the As mobilization in these groundwaters was a direct result of their elevated pH and oxidative conditions. The volcanic glass layers present in the aquifer matrix were hypothesized as one of the possible sources of As to the groundwaters. Here, we examine the groundwater chemistry of the Santiago del Estero province of Chaco-Pampean Plains of Argentina, and test these hypotheses by using hydrogeochemical modeling within the framework of the regional geologic-tectonic setting. The study area is located in the active foreland of the Andean orogenic belt, which forms a continental arc setting, and is dotted with several hot springs. Rhyolitic volcanic glass fragments derived from arc volcanism are abundant within the aeolian-fluvial aquifer sediments, and are related to the paleo-igneous extrusion in the vicinity. Hydrogeochemical analyses show that the groundwater is in predominantly oxidative condition. In addition, some of the groundwaters exhibit very high Na, Cl- and SO42- concentrations. It is hypothesized in this study that the groundwater chemistry has largely evolved by dissolution of rhyolitic volcanic glass fragments contained within the aquifer sediments along with mixing with saline surface waters from, adjoining salinas, which are thought to be partially evaporated remnants of a paleo inland sea. Flow path modeling, stability diagrams, and thermodynamic analyses undertaken in this study indicate that the dominant evolutionary processes include ion exchange reactions, chemical weathering of silicate and evaporites, in monosialitization-dominated weathering. Geochemical modeling predicts that plagioclase feldspar and volcanic glass are the major solids phases that contribute metal cations and dissolved silica to the local groundwaters. Co-influxed oxyanions, with similar ionic radii and structure (e.g. Mo

Modelling raw water quality: development of a drinking water management tool.

Science.gov (United States)

Kübeck, Ch; van Berk, W; Bergmann, A

2009-01-01

Ensuring future drinking water supply requires a tough management of groundwater resources. However, recent practices of economic resource control often does not involve aspects of the hydrogeochemical and geohydraulical groundwater system. In respect of analysing the available quantity and quality of future raw water, an effective resource management requires a full understanding of the hydrogeochemical and geohydraulical processes within the aquifer. For example, the knowledge of raw water quality development within the time helps to work out strategies of water treatment as well as planning finance resources. On the other hand, the effectiveness of planed measurements reducing the infiltration of harmful substances such as nitrate can be checked and optimized by using hydrogeochemical modelling. Thus, within the framework of the InnoNet program funded by Federal Ministry of Economics and Technology, a network of research institutes and water suppliers work in close cooperation developing a planning and management tool particularly oriented on water management problems. The tool involves an innovative material flux model that calculates the hydrogeochemical processes under consideration of the dynamics in agricultural land use. The program integrated graphical data evaluation is aligned on the needs of water suppliers.

Probabilistic transport models for fusion

International Nuclear Information System (INIS)

Milligen, B.Ph. van; Carreras, B.A.; Lynch, V.E.; Sanchez, R.

2005-01-01

A generalization of diffusive (Fickian) transport is considered, in which particle motion is described by probability distributions. We design a simple model that includes a critical mechanism to switch between two transport channels, and show that it exhibits various interesting characteristics, suggesting that the ideas of probabilistic transport might provide a framework for the description of a range of unusual transport phenomena observed in fusion plasmas. The model produces power degradation and profile consistency, as well as a scaling of the confinement time with system size reminiscent of the gyro-Bohm/Bohm scalings observed in fusion plasmas, and rapid propagation of disturbances. In the present work we show how this model may also produce on-axis peaking of the profiles with off-axis fuelling. It is important to note that the fluid limit of a simple model like this, characterized by two transport channels, does not correspond to the usual (Fickian) transport models commonly used for modelling transport in fusion plasmas, and behaves in a fundamentally different way. (author)

Stable isotope and hydrogeochemical studies of Beaver Lake and Lake Radok, MacRobertson Land, East Antarctica

International Nuclear Information System (INIS)

Wand, U.; Hermichen, W.D.; Hoefling, R.; Muehle, K.

1987-01-01

Beaver Lake and Lake Radok, the largest known epishelf and the deepest freshwater lake on the Antarctic continent, respectively, were isotopically (δ 2 H, δ 18 O) and hydrogeochemically studied. Lake Radok is an isothermal and non-stratified, i.e. homogeneous water body, while Beaver Lake is stratified with respect to temperature, salinity and isotopic composition. The results for the latter attest to freshwater (derived from snow and glacier melt) overlying seawater. (author)

Stable isotope and hydrogeochemical studies of Beaver Lake and Radok Lake, MacRobertson Land, East Antarctica

International Nuclear Information System (INIS)

Wand, U.; Hermichen, W.D.

1988-01-01

Beaver Lake and Radok Lake, the largest known epishelf lake and the deepest freshwater lake on the Antarctic continent, respectively, were isotopically (δ 2 H, δ 18 O) and hydrogeochemically studied. Radok Lake is an isothermal and nonstratified, i.e. homogeneous water body, while Beaver Lake is stratified with respect to temperature, salinity and isotopic composition. The results for the latter attest to freshwater (derived from snow and glacier melt) overlying seawater. (author)

Modelling of transport phenomena

International Nuclear Information System (INIS)

Itoh, Kimitaka; Itoh, Sanae; Fukuyama, Atsushi.

1993-09-01

In this review article, we discuss key features of the transport phenomena and theoretical modelling to understand them. Experimental observations have revealed the nature of anomalous transport, i.e., the enhancement of the transport coefficients by the gradients of the plasma profiles, the pinch phenomena, the radial profile of the anomalous transport coefficients, the variation of the transport among the Bohm diffusion, Pseudo-classical confinement, L-mode and variety of improved confinement modes, and the sudden jumps such as L-H transition. Starting from the formalism of the transport matrix, the modelling based on the low frequency instabilities are reviewed. Theoretical results in the range of drift wave frequency are examined. Problems in theories based on the quasilinear and mixing-length estimates lead to the renewal of the turbulence theory, and the physics picture of the self-sustained turbulence is discussed. The theory of transport using the fluid equation of plasma is developed, showing that the new approach is very promising in explaining abovementioned characteristics of anomalous transport in both L-mode and improved confinement plasmas. The interference of the fluxes is the key to construct the physics basis of the bifurcation theory for the L-H transition. The present status of theories on the mechanisms of improved confinement is discussed. Modelling on the nonlocal nature of transport is briefly discussed. Finally, the impact of the anomalous transport on disruptive phenomena is also described. (author) 95 refs

FORTRAN computer programs to process Savannah River Laboratory hydrogeochemical and stream-sediment reconnaissance data

International Nuclear Information System (INIS)

Zinkl, R.J.; Shettel, D.L. Jr.; D'Andrea, R.F. Jr.

1980-03-01

FORTRAN computer programs have been written to read, edit, and reformat the hydrogeochemical and stream-sediment reconnaissance data produced by Savannah River Laboratory for the National Uranium Resource Evaluation program. The data are presorted by Savannah River Laboratory into stream sediment, ground water, and stream water for each 1 0 x 2 0 quadrangle. Extraneous information is eliminated, and missing analyses are assigned a specific value (-99999.0). Negative analyses are below the detection limit; the absolute value of a negative analysis is assumed to be the detection limit

Explorative analysis of microbes, colloids and gases together with microbial modelling. Site description model SDM-Site Laxemar

International Nuclear Information System (INIS)

Hallbeck, Lotta; Pedersen, Karsten

2008-08-01

The work has involved the development of descriptive and mathematical models for groundwaters in relation to rock domains, fracture domains and deformation zones. Past climate changes are the major driving force for hydrogeochemical changes and therefore of fundamental importance for understanding the palaeohydrogeological, palaeohydrogeochemical and present evolution of groundwater in the crystalline bedrock of the Fennoscandian Shield. Understanding current undisturbed hydrochemical conditions at the proposed repository site is important when predicting future changes in groundwater chemistry. The causes of copper corrosion and/or bentonite degradation are of particular interest as they may jeopardise the long-term integrity of the planned SKB repository system. Thus, the following variables are considered for the hydrogeochemical site descriptive modelling: pH, Eh, sulphur species, iron, manganese, carbonate, phosphate, nitrogen species, total dissolved solids (TDS), isotopes, colloids, fulvic and humic acids and microorganisms. In addition, dissolved gases (e.g. carbon dioxide, methane and hydrogen) are of interest because of their likely participation in microbial reactions. In this series of reports, the final hydrogeochemical evaluation work of the site investigation at the Laxemar site, is presented. The work was conducted by SKB's hydrogeochemical project group, ChemNet, which consists of independent consultants and Univ. researchers with expertise in geochemistry, hydrochemistry, hydrogeochemistry, microbiology, geomicrobiology, analytical chemistry etc. The resulting site descriptive model version, mainly based on available primary data from the extended data freeze L2.3 (Nov 2007). This report focuses on microbiology, colloids and gases. Several methods must be used to characterise active microbial communities in groundwater. Microbial parameters of interest are the total number of cells (TNC) and the presence of various metabolic groups of

Hydrogeochemical assessment of mine-impacted water and sediment of iron ore mining

Science.gov (United States)

Nur Atirah Affandi, Fatin; Kusin, Faradiella Mohd; Aqilah Sulong, Nur; Madzin, Zafira

2018-04-01

This study was carried out to evaluate the hydrogeochemical behaviour of mine-impacted water and sediment of a former iron ore mining area. Sampling of mine water and sediment were carried out at selected locations within the mine including the former mining ponds, mine tailings and the nearby stream. The water samples were analysed for their hydrochemical facies, major and trace elements including heavy metals. The water in the mining ponds and the mine tailings was characterised as highly acidic (pH 2.54-3.07), but has near-neutral pH in the nearby stream. Results indicated that Fe and Mn in water have exceeded the recommended guidelines values and was also supported by the results of geochemical modelling. The results also indicated that sediments in the mining area were contaminated with Cd and As as shown by the potential ecological risk index values. The total risk index of heavy metals in the sediment were ranked in the order of Cd>As>Pb>Cu>Zn>Cr. Overall, the extent of potential ecological risks of the mining area were categorised as having low to moderate ecological risk.

Stochastic models of intracellular transport

KAUST Repository

Bressloff, Paul C.

2013-01-09

The interior of a living cell is a crowded, heterogenuous, fluctuating environment. Hence, a major challenge in modeling intracellular transport is to analyze stochastic processes within complex environments. Broadly speaking, there are two basic mechanisms for intracellular transport: passive diffusion and motor-driven active transport. Diffusive transport can be formulated in terms of the motion of an overdamped Brownian particle. On the other hand, active transport requires chemical energy, usually in the form of adenosine triphosphate hydrolysis, and can be direction specific, allowing biomolecules to be transported long distances; this is particularly important in neurons due to their complex geometry. In this review a wide range of analytical methods and models of intracellular transport is presented. In the case of diffusive transport, narrow escape problems, diffusion to a small target, confined and single-file diffusion, homogenization theory, and fractional diffusion are considered. In the case of active transport, Brownian ratchets, random walk models, exclusion processes, random intermittent search processes, quasi-steady-state reduction methods, and mean-field approximations are considered. Applications include receptor trafficking, axonal transport, membrane diffusion, nuclear transport, protein-DNA interactions, virus trafficking, and the self-organization of subcellular structures. © 2013 American Physical Society.

Hydrogeochemical assessment of crystaline rock for radioactive waste disposal: the Stripa experience

International Nuclear Information System (INIS)

Andrews, J.; Fontes, J.C.; Fritz, P.; Nordstroem, K.

1988-08-01

This report presents a program for the hydro-geochemical assessment of a crystalline rock site for radioactive waste disposal. It is based upon experience gained during the international program of hydrochemical work at the Stripa mine. The important result of this work are summarized in this report and fuller details may be found in the separate final reports of the Phase 1 and Phase 2 geochemical investigations of the Stripa groundwaters. The present report summarizes the general sampling requirements for a successful hydrochecmical investigation; the isotopic and chemical parameters which should be determined an the geochemical characterization of the rock matrix necessary for the interpretation of hydrochemistry. A general strategy for site evaluation by geochemical methods is presented. (authors)

Transport of Escherichia coli phage through saturated porous media considering managed aquifer recharge.

Science.gov (United States)

Zhang, Wenjing; Li, Shuo; Wang, Shuang; Lei, Liancheng; Yu, Xipeng; Ma, Tianyi

2018-03-01

Virus is one of the most potentially harmful microorganisms in groundwater. In this paper, the effects of hydrodynamic and hydrogeochemical conditions on the transportation of the colloidal virus considering managed aquifer recharge were systematically investigated. Escherichia coli phage, vB_EcoM-ep3, has a broad host range and was able to lyse pathogenic Escherichia coli. Bacteriophage with low risk to infect human has been found extensively in the groundwater environment, so it is considered as a representative model of groundwater viruses. Laboratory studies were carried out to analyze the transport of the Escherichia coli phage under varying conditions of pH, ionic strength, cation valence, flow rate, porous media, and phosphate buffer concentration. The results indicated that decreasing the pH will increase the adsorption of Escherichia coli phage. Increasing the ionic strength, either Na + or Ca 2+ , will form negative condition for the migration of Escherichia coli phage. A comparison of different cation valence tests indicated that changes in transport and deposition were more pronounced with divalent Ca 2+ than monovalent Na + . As the flow rate increases, the release of Escherichia coli phage increases and the retention of Escherichia coli phage in the aquifer medium reduces. Changes in porous media had a significant effect on Escherichia coli phage migration. With increase of phosphate buffer concentration, the suspension stability and migration ability of Escherichia coli phage are both increased. Based on laboratory-scale column experiments, a one-dimensional transport model was established to quantitatively describe the virus transport in saturated porous medium.

Application of Kriging to hydrogeochemical data from the National Uranium Resource Evaluation Program

International Nuclear Information System (INIS)

Myers, D.E.; Begovich, C.L.; Butz, T.R.; Kane, V.E.

1980-12-01

The Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) Program is an important part of the data collection segment of the NURE Program. This report presents the preliminary results of applying a new geostatistical tool, known as Kriging, to HSSR data from the Plainview Quadrangle in Texas. The essential conclusion of this report is that Kriging can be useful in characterizing geochemical data and identification of the anomalous geographic regions used in resource appraisal. Computer codes were prepared for use either on other variables or stream sediment data and/or data from other quadrangles. Several ways of using Kriging to enhance HSSR data for the purpose of identifying favorable areas were identified

SATURATED ZONE FLOW AND TRANSPORT MODEL ABSTRACTION

International Nuclear Information System (INIS)

B.W. ARNOLD

2004-01-01

The purpose of the saturated zone (SZ) flow and transport model abstraction task is to provide radionuclide-transport simulation results for use in the total system performance assessment (TSPA) for license application (LA) calculations. This task includes assessment of uncertainty in parameters that pertain to both groundwater flow and radionuclide transport in the models used for this purpose. This model report documents the following: (1) The SZ transport abstraction model, which consists of a set of radionuclide breakthrough curves at the accessible environment for use in the TSPA-LA simulations of radionuclide releases into the biosphere. These radionuclide breakthrough curves contain information on radionuclide-transport times through the SZ. (2) The SZ one-dimensional (I-D) transport model, which is incorporated in the TSPA-LA model to simulate the transport, decay, and ingrowth of radionuclide decay chains in the SZ. (3) The analysis of uncertainty in groundwater-flow and radionuclide-transport input parameters for the SZ transport abstraction model and the SZ 1-D transport model. (4) The analysis of the background concentration of alpha-emitting species in the groundwater of the SZ

The hydrogeochemical characteristics of the certain uranium deposit and their relationship with uranium mineralization

International Nuclear Information System (INIS)

Li Huanguang

2010-01-01

On the basis of previous work, this paper studies characteristics of the stratum,lithology,structure, ore bodies, ore and wall rocks and the relations between hydrochemical characteristics and uranium mineraliztion are stressed and anaysed.The environmental index of hydrogeochemisty is closely related with the uranium form, migration,and precipitation. According to negative ion, the ground water is classified into HCO3-,SO42-, HCO3--SO42-and HCO3-Cl-. For deposit genesis, uranium source comes from two parts; there are five mineralizations such as leaching, adsorption, hydrogeochemistry, palaeo-climatology and geothermal mineralization. Hydrogeochemical mineralization is the key process.. (authors)

Hydrogeochemical characteristics of the River Idrijca (Slovenia

Directory of Open Access Journals (Sweden)

Tjaša Kanduč

2008-06-01

Full Text Available The hydrogeochemical and isotope characteristics of the River Idrijca, Slovenia, where the world’s second largest mercury (Hg mine is located, were investigated. The River Idrijca, a typical steep mountain river has an HCO3- - Ca2+ - Mg2+ chemical composition. Its Ca2+/Mg2+ molar ratio indicates that dolomite weathering prevails in the watershed. The River Idrijca and its tributaries are over saturated with respect to calcite and dolomite. The pCO2 pressure is up to 13 times over atmospheric pressure and represents a source of CO2 to the atmosphere. δ18O values in river water indicate primary control from precipitation and enrichment of the heavy oxygen isotope of infiltrating water recharging the River Idrijca from its slopes.The δ13 CDIC values range from −10.8 to −6.6 ‰ and are controlled by biogeochemical processes in terrestrial environments and in the stream: 1 exchange with atmospheric CO2, 2 degradation of organic matter, 3 dissolution of carbonates, and 4 tributaries. The contributions of these inputs were calculated according to steady state equations and are estimated to be -11 %: 19 %: 31 %: 61 % in the autumn and 0 %: 6 %: 9 %: 35 % in the spring sampling seasons.

Solute transport in coupled inland-coastal water systems. General conceptualisation and application to Forsmark

Energy Technology Data Exchange (ETDEWEB)

Jarsjoe, Jerker; Destouni, Georgia; Persson, Klas; Prieto, Carmen (Dept. of Physical Geography, Quaternary Geology, Stockholm Univ., Stockholm (Sweden))

2007-12-15

diffuse and occurring through SGD, small transient streams and/or coastal wetlands. Regarding transport quantifications, hydrogeochemical characteristics and pollution source loads may generally differ between larger, monitored catchments and smaller unmonitored coastal catchments. Since national hydrological monitoring data systematically exclude smaller, coastal catchments, they may not be representative for conditions in Forsmark (or Laxemar-Simpevarp). This emphasises the importance of extending in time the recently started hydrological and hydrogeochemical data series in the Forsmark and Laxemar-Simpevarp coastal catchment areas, since they are in effect unmonitored from a hydrological viewpoint, due to the lack of extended discharge time series. In the performed initial demonstration analysis of solute transport pathways from deep groundwater to recipients at the surface, we considered the main scenarios: (I) transport in the Quaternary deposits-bedrock interface zone only, and (II) transport in the coupled groundwater-surface water system. Considering mean travel times from each model cell to the coast, and disregarding travel times in the deep bedrock domain itself (which may be added to the here presented values), results show that travel times in scenario (II) were less than 4 years in 90% of the considered model area. Travel times were longer in scenario (I) with values higher than 10 years in 40% of the catchment area. These results are based on the assumption that the pathways do not go through zones of near-stagnant groundwater. If they would do so (and the above assumption is violated), results show that travel times can be considerably longer, for instance exceeding 400 years in half of the model area in scenario (I). Considering possible solute attenuation (caused by e.g. biogeochemical reactions or decay) along the hydrological transport pathways to inland surface waters and to the coast, we estimate solute mass delivery factors, representing the

Transport properties site descriptive model. Guidelines for evaluation and modelling

International Nuclear Information System (INIS)

Berglund, Sten; Selroos, Jan-Olof

2004-04-01

This report describes a strategy for the development of Transport Properties Site Descriptive Models within the SKB Site Investigation programme. Similar reports have been produced for the other disciplines in the site descriptive modelling (Geology, Hydrogeology, Hydrogeochemistry, Rock mechanics, Thermal properties, and Surface ecosystems). These reports are intended to guide the site descriptive modelling, but also to provide the authorities with an overview of modelling work that will be performed. The site descriptive modelling of transport properties is presented in this report and in the associated 'Strategy for the use of laboratory methods in the site investigations programme for the transport properties of the rock', which describes laboratory measurements and data evaluations. Specifically, the objectives of the present report are to: Present a description that gives an overview of the strategy for developing Site Descriptive Models, and which sets the transport modelling into this general context. Provide a structure for developing Transport Properties Site Descriptive Models that facilitates efficient modelling and comparisons between different sites. Provide guidelines on specific modelling issues where methodological consistency is judged to be of special importance, or where there is no general consensus on the modelling approach. The objectives of the site descriptive modelling process and the resulting Transport Properties Site Descriptive Models are to: Provide transport parameters for Safety Assessment. Describe the geoscientific basis for the transport model, including the qualitative and quantitative data that are of importance for the assessment of uncertainties and confidence in the transport description, and for the understanding of the processes at the sites. Provide transport parameters for use within other discipline-specific programmes. Contribute to the integrated evaluation of the investigated sites. The site descriptive modelling of

Progress in transport modelling of internal transport barrier plasmas in JET

International Nuclear Information System (INIS)

Tala, T.; Bourdelle, C.; Imbeaux, F.; Moreau, D.; Garbet, X.; Joffrin, E.; Laborde, L.; Litaudon, X.; Mazon, D.; Parail, V.; Corrigan, G.; Heading, D.; Crisanti, F.; Mantica, P.; Salmi, A.; Strand, P.; Weiland, J.

2005-01-01

This paper will report on the recent progress in transport modelling of Internal Transport Barrier (ITB) plasmas. Two separate issues will be covered, fully predictive transport modelling of ITBs in the multi-tokamak database, including micro-stability analyses of ITBs, and predictive closed-loop (i.e. real-time control) transport simulations of the q-profile and ITBs. For the first time, the predictive capabilities of the mixed Bohm/GyroBohm and Weiland transport models are investigated with discharges from the ITPA ITB database by fully predictive transport simulations. The predictive transport simulations with the Bohm/GyroBohm model agree very well with experimental results from JET and JT-60U. In order to achieve a good agreement in DIII-D, the stabilisation had to be included into the model, showing the significant role played by the stabilisation in governing the physics of the ITBs. The significant role of the stabilisation is also emphasised by the gyrokinetic analysis. The Weiland transport model shows only limited agreement between the model predictions and experimental results with respect to the formation and location of the ITB. The fully predictive closed-loop simulations with real-time control of the q-profile and ITB show that it is possible to reach various set-point profiles for q and ITB and control them for longer than a current diffusion time in JET using the same real-time control technique as in the experiments. (author)

Using hydrogeochemical data from natural environments to improve models of radionuclide speciation in groundwaters

International Nuclear Information System (INIS)

Read, D.; Hooker, P.

1991-01-01

It is essential that computer-based models used in the safety assessment of radioactive waste repositories accurately represent the processes occurring in real field systems. Confidence in long-term predictions of radionuclide migration will then depend upon the completeness of data available, particularly those obtained from the disposal site, and correct implementation of the model. The study of natural geochemical systems provides information on the adequacy of the underlying generic database and enhances our understanding of the transport mechanisms which form the basis of performance assessment. This paper concentrates on speciation-solubility modelling and describes four natural occurrences of uranium, each of which displays a different facet of uranium migration behaviour. The attributes of each site and the means by which uranium is immobilised are described. Retardation is highly species specific and this is illustrated through the use of site data in equilibrium speciation and coupled chemical transport calculations. Oxidation of U(IV) to U(VI) species promotes leaching of uranium ore at all the locations studied, emphasising the need to ensure that reducing conditions persist in a repository dominated by its actinide inventory. 5 figs., 46 refs

Simplified models of transport and reactions in conditions of CO2 storage in saline aquifers

Science.gov (United States)

Suchodolska, Katarzyna; Labus, Krzysztof

2016-04-01

Simple hydrogeochemical models may serve as tools of preliminary assessment of CO2 injection and sequestraton impact on the aquifer and cap-rocks. In order to create models of reaction and transport in conditions of CO2 injection and storage, the TOUGHREACT simulator, and the Geochemist's Workbench software were applied. The chemical composition of waters for kinetic transport models based on the water - rock equilibrium calculations. Analyses of reaction and transport of substances during CO2 injection and storage period were carried out in three scenarios: one-dimensional radial model, and two-dimensional model of CO2 injection and sequestration, and one-dimensional model of aquifer - cap-rock interface. Modeling was performed in two stages. The first one simulated the immediate changes in the aquifer and insulating rocks impacted by CO2 injection (100 days in case of reaction model and 30 years in transport and reaction model), the second - enabled assessment of long-term effects of sequestration (20000 years). Reactions' quality and progress were monitored and their effects on formation porosity and sequestration capacity in form of mineral, residual and free phase of CO2 were calculated. Calibration of numerical models (including precipitation of secondary minerals, and correction of kinetics parameters) describing the initial stage of injection, was based on the experimental results. Modeling allowed to evaluate the pore space saturation with gas, changes in the composition and pH of pore waters, relationships between porosity and permeability changes and crystallization or dissolution minerals. We assessed the temporal and spatial extent of crystallization processes, and the amount of carbonates trapping. CO2 in mineral form. The calculated sequestration capacity of analyzed formations reached n·100 kg/m3 for the: dissolved phase - CO(aq), gas phase - CO2(g) and mineral phase, but as much as 101 kg/m3 for the supercritical phase - SCCO2. Processes of gas

Transport modelling for ergodic configurations

International Nuclear Information System (INIS)

Runov, A.; Kasilov, S.V.; McTaggart, N.; Schneider, R.; Bonnin, X.; Zagorski, R.; Reiter, D.

2004-01-01

The effect of ergodization, either by additional coils like in TEXTOR-dynamic ergodic divertor (DED) or by intrinsic plasma effects like in W7-X, defines the need for transport models that are able to describe the ergodic configuration properly. A prerequisite for this is the concept of local magnetic coordinates allowing a correct discretization with minimized numerical errors. For these coordinates the appropriate full metric tensor has to be known. To study the transport in complex edge geometries (in particular for W7-X) two possible methods are used. First, a finite-difference discretization of the transport equations on a custom-tailored grid in local magnetic coordinates is used. This grid is generated by field-line tracing to guarantee an exact discretization of the dominant parallel transport (thus also minimizing the numerical diffusion problem). The perpendicular fluxes are then interpolated in a plane (a toroidal cut), where the interpolation problem for a quasi-isotropic system has to be solved by a constrained Delaunay triangulation (keeping the structural information for magnetic surfaces if they exist) and discretization. All toroidal terms are discretized by finite differences. Second, a Monte Carlo transport model originally developed for the modelling of the DED configuration of TEXTOR is used. A generalization and extension of this model was necessary to be able to handle W7-X. The model solves the transport equations with Monte Carlo techniques making use of mappings of local magnetic coordinates. The application of this technique to W7-X in a limiter-like configuration is presented. The decreasing dominance of parallel transport with respect to radial transport for electron heat, ion heat and particle transport results in increasingly steep profiles for the respective quantities within the islands. (author)

Hydrogeochemical investigations of groundwater in Ziarat valley, Baluchistan

International Nuclear Information System (INIS)

Akram, W.; Ahmad, M.; Rafiq, M.

2010-03-01

Present study was undertaken in Ziarat Valley, Baluchistan to investigate recent trends of groundwater chemistry (geochemical facies, geochemical evolution) and assess the groundwater quality for drinking and irrigation purposes. For this purpose samples of groundwater (open wells, tube wells, karezes, springs) were periodically collected from different locations and analyzed for dissolved chemical constituents such as sodium, potassium, magnesium, calcium, carbonate, bicarbonate, chloride and sulphate. The data indicated that concentrations of sodium, potassium, calcium and magnesium vary from 5 to 113,0.3 to 3,18 to 62 and 27 to 85 mg/l respectively. Values of anions i. e. bicarbonate, chloride and sulphate lie in the range of 184 to 418, 14 to 77 and 8 to 318 mg/l respectively. Hydrogeochemical facies revealed that groundwater in the study area belongs to Mg-HCO/sub 3/ type at 72% surveyed locations. Dissolution and calcite precipitation were found to be the main processes controlling the groundwater chemistry. Chemical quality was assessed for drinking use by comparing with WHO, Indian and proposed national standards, and for irrigation use using empirical indices such as SAR and RSC. The results show that groundwater is quite suitable for irrigation and drinking purposes. (author)

Explorative analysis of microbes, colloids and gases together with microbial modelling. Site description model SDM-Site Laxemar

Energy Technology Data Exchange (ETDEWEB)

Hallbeck, Lotta; Pedersen, Karsten (Microbial Analytics Sweden AB, Goeteborg (Sweden))

2008-08-15

The work has involved the development of descriptive and mathematical models for groundwaters in relation to rock domains, fracture domains and deformation zones. Past climate changes are the major driving force for hydrogeochemical changes and therefore of fundamental importance for understanding the palaeohydrogeological, palaeohydrogeochemical and present evolution of groundwater in the crystalline bedrock of the Fennoscandian Shield. Understanding current undisturbed hydrochemical conditions at the proposed repository site is important when predicting future changes in groundwater chemistry. The causes of copper corrosion and/or bentonite degradation are of particular interest as they may jeopardise the long-term integrity of the planned SKB repository system. Thus, the following variables are considered for the hydrogeochemical site descriptive modelling: pH, Eh, sulphur species, iron, manganese, carbonate, phosphate, nitrogen species, total dissolved solids (TDS), isotopes, colloids, fulvic and humic acids and microorganisms. In addition, dissolved gases (e.g. carbon dioxide, methane and hydrogen) are of interest because of their likely participation in microbial reactions. In this series of reports, the final hydrogeochemical evaluation work of the site investigation at the Laxemar site, is presented. The work was conducted by SKB's hydrogeochemical project group, ChemNet, which consists of independent consultants and Univ. researchers with expertise in geochemistry, hydrochemistry, hydrogeochemistry, microbiology, geomicrobiology, analytical chemistry etc. The resulting site descriptive model version, mainly based on available primary data from the extended data freeze L2.3 (Nov 2007). This report focuses on microbiology, colloids and gases. Several methods must be used to characterise active microbial communities in groundwater. Microbial parameters of interest are the total number of cells (TNC) and the presence of various metabolic groups of

Electronic transport in VO2—Experimentally calibrated Boltzmann transport modeling

International Nuclear Information System (INIS)

Kinaci, Alper; Rosenmann, Daniel; Chan, Maria K. Y.; Kado, Motohisa; Ling, Chen; Zhu, Gaohua; Banerjee, Debasish

2015-01-01

Materials that undergo metal-insulator transitions (MITs) are under intense study, because the transition is scientifically fascinating and technologically promising for various applications. Among these materials, VO 2 has served as a prototype due to its favorable transition temperature. While the physical underpinnings of the transition have been heavily investigated experimentally and computationally, quantitative modeling of electronic transport in the two phases has yet to be undertaken. In this work, we establish a density-functional-theory (DFT)-based approach with Hubbard U correction (DFT + U) to model electronic transport properties in VO 2 in the semiconducting and metallic regimes, focusing on band transport using the Boltzmann transport equations. We synthesized high quality VO 2 films and measured the transport quantities across the transition, in order to calibrate the free parameters in the model. We find that the experimental calibration of the Hubbard correction term can efficiently and adequately model the metallic and semiconducting phases, allowing for further computational design of MIT materials for desirable transport properties

Biological transportation networks: Modeling and simulation

KAUST Repository

Albi, Giacomo

2015-09-15

We present a model for biological network formation originally introduced by Cai and Hu [Adaptation and optimization of biological transport networks, Phys. Rev. Lett. 111 (2013) 138701]. The modeling of fluid transportation (e.g., leaf venation and angiogenesis) and ion transportation networks (e.g., neural networks) is explained in detail and basic analytical features like the gradient flow structure of the fluid transportation network model and the impact of the model parameters on the geometry and topology of network formation are analyzed. We also present a numerical finite-element based discretization scheme and discuss sample cases of network formation simulations.

Model Comparison for Electron Thermal Transport

Science.gov (United States)

Moses, Gregory; Chenhall, Jeffrey; Cao, Duc; Delettrez, Jacques

2015-11-01

Four electron thermal transport models are compared for their ability to accurately and efficiently model non-local behavior in ICF simulations. Goncharov's transport model has accurately predicted shock timing in implosion simulations but is computationally slow and limited to 1D. The iSNB (implicit Schurtz Nicolai Busquet electron thermal transport method of Cao et al. uses multigroup diffusion to speed up the calculation. Chenhall has expanded upon the iSNB diffusion model to a higher order simplified P3 approximation and a Monte Carlo transport model, to bridge the gap between the iSNB and Goncharov models while maintaining computational efficiency. Comparisons of the above models for several test problems will be presented. This work was supported by Sandia National Laboratory - Albuquerque and the University of Rochester Laboratory for Laser Energetics.

X-ray CT-Derived Soil Characteristics Explain Varying Air, Water, and Solute Transport Properties across a Loamy Field

DEFF Research Database (Denmark)

Paradelo Pérez, Marcos; Katuwal, Sheela; Møldrup, Per

2016-01-01

-derived parameters by using a best subsets regression analysis. The regression coefficients improved using CTmatrix, limiting macroporosity, and genus density, while the best model for t0.05 used CTmatrix only. The scanning resolution and the time for soil structure development after mechanical activities could......The characterization of soil pore space geometry is important for explaining fluxes of air, water, and solutes through soil and understanding soil hydrogeochemical functions. X-ray computed tomography (CT) can be applied for this characterization, and in this study CT-derived parameters were used...... to explain water, air, and solute transport through soil. Forty-five soil columns (20 by 20 cm) were collected from an agricultural field in Estrup, Denmark, and subsequently scanned using a medical CT scanner. Nonreactive tracer leaching experiments were performed in the laboratory along with measurements...

Vadose Zone Transport Field Study: Summary Report

Energy Technology Data Exchange (ETDEWEB)

Ward, Andy L.; Conrad, Mark E.; Daily, William D.; Fink, James B.; Freedman, Vicky L.; Gee, Glendon W.; Hoversten, Gary M.; Keller, Jason M.; Majer, Ernest L.; Murray, Christopher J.; White, Mark D.; Yabusaki, Steven B.; Zhang, Z. F.

2006-07-31

migration (e.g. BC Cribs and Trenches). The improved models have been also coupled with inverse models and newly-developed parameter scaling techniques to allow estimation of field-scale and effective transport parameters for the vadose zone. The development and utility of pedotransfer functions for describing fine-scale hydrogeochemical heterogeneity and for incorporating this heterogeneity into reactive transport models was explored. An approach based on grain-size statistics appears feasible and has been used to describe heterogeneity in hydraulic properties and sorption properties, such as the cation exchange capacity and the specific surface area of Hanford sediments. This work has also led to the development of inverse modeling capabilities for time-dependent, subsurface, reactive transport with transient flow fields using an automated optimization algorithm. In addition, a number of geophysical techniques investigated for their potential to provide detailed information on the subtle changes in lithology and bedding surfaces; plume delineation, leak detection. High-resolution resistivity is now being used for detecting saline plumes at several waste sites at Hanford, including tank farms. Results from the field studies and associated analysis have appeared in more than 46 publications generated over the past 4 years. These publications include test plans and status reports, in addition to numerous technical notes and peer reviewed papers.

Hydrogeochemical And Isotopic Investigation Of Nasrettin Hoca Springs, Eskisehir, Turkey

Directory of Open Access Journals (Sweden)

Mehmet ÇELİK

2013-06-01

Full Text Available The aims of this study are to investigate the water quality, the contamination and water-rock interaction of the Nasrettin Hoca springs, with an ultimate aim of establishing protection measures. Within the scope of this study, the springs in and around the catchment area, Bağbaşı springs, Hatip spring, Ali spring, Saracık Fountain and Babadat spring, were investigated. The springs are of Ca-Mg-HCO3 type when basic hydrogeochemical features are considered, are under the influence of marble-limestone and meta ophiolitic units located in the recharge area and are of shallow circulation. The trace element contents of the springs show the influence of the carbonate rocks comprising the reservoir (Sr and the basement rocks (Ni, Al. The protection areas of Nasrettin Hoca springs against contamination are determined as three different zones by considering the hydrogeologic and topographical features of the region and the Turkish Standards

Linking air and water transport in intact soils to macropore characteristics inferred from X-ray computed tomography

DEFF Research Database (Denmark)

Katuwal, S.; Nørgaard, Trine; Møldrup, Per

2015-01-01

Soil macropores often control fluid flow and solute transport, and quantification of macropore characteristics including their variability in space and time are essential to predict soil hydraulic and hydrogeochemical functions. In this study, measurements of air and solute transport properties...... and direct macropore visualization by X-ray CT scanning were carried out on 17 large (19-cm diam.; 20-cm length) undisturbed soil columns sampled across a field site (Silstrup, Denmark) with natural gradients in texture and density. Air permeability (ka) at in-situ water content and -20 hPa of matric......-porosity, suggesting that density is the main control of functional soil structure and gas and solute transport at the Silstrup site. Linking gas transport and chemical tracer experiments with X-ray CT based visualization and quantification of macro-porosity was found to be a powerful method to understand field scale...

Radionuclide Transport Models Under Ambient Conditions

International Nuclear Information System (INIS)

Moridis, G.; Hu, Q.

2000-01-01

The purpose of this Analysis/Model Report (AMR) is to evaluate (by means of 2-D semianalytical and 3-D numerical models) the transport of radioactive solutes and colloids in the unsaturated zone (UZ) under ambient conditions from the potential repository horizon to the water table at Yucca Mountain (YM), Nevada. This is in accordance with the ''AMR Development Plan U0060, Radionuclide Transport Models Under Ambient Conditions'' (CRWMS M and O 1999a). This AMR supports the UZ Flow and Transport Process Model Report (PMR). This AMR documents the UZ Radionuclide Transport Model (RTM). This model considers: the transport of radionuclides through fractured tuffs; the effects of changes in the intensity and configuration of fracturing from hydrogeologic unit to unit; colloid transport; physical and retardation processes and the effects of perched water. In this AMR they document the capabilities of the UZ RTM, which can describe flow (saturated and/or unsaturated) and transport, and accounts for (a) advection, (b) molecular diffusion, (c) hydrodynamic dispersion (with full 3-D tensorial representation), (d) kinetic or equilibrium physical and/or chemical sorption (linear, Langmuir, Freundlich or combined), (e) first-order linear chemical reaction, (f) radioactive decay and tracking of daughters, (g) colloid filtration (equilibrium, kinetic or combined), and (h) colloid-assisted solute transport. Simulations of transport of radioactive solutes and colloids (incorporating the processes described above) from the repository horizon to the water table are performed to support model development and support studies for Performance Assessment (PA). The input files for these simulations include transport parameters obtained from other AMRs (i.e., CRWMS M and O 1999d, e, f, g, h; 2000a, b, c, d). When not available, the parameter values used are obtained from the literature. The results of the simulations are used to evaluate the transport of radioactive solutes and colloids, and

Synthesizing Earth's geochemical data for hydrogeochemical analysis

Science.gov (United States)

Brantley, S. L.; Kubicki, J.; Miller, D.; Richter, D.; Giles, L.; Mitra, P.

2007-12-01

For over 200 years, geochemical, microbiological, and chemical data have been collected to describe the evolution of the surface earth. Many of these measurements are data showing variations in time or in space. To forward predict hydrologic response to changing tectonic, climatic, or anthropogenic forcings requires synthesis of these data and utilization in hydrogeochemical models. Increasingly, scientists are attempting to synthesize such data in order to make predictions for new regions or for future time periods. However, to make such complex geochemical data accessible requires development of sophisticated cyberinfrastructures that both invite uploading as well as usage of data. Two such cyberinfrastructure (CI) initiatives are currently developing, one to invite and promote the use of environmental kinetics data (laboratory time course data) through ChemxSeer, and the other to invite and promote the use of spatially indexed geochemical data for the Earth's Critical Zone through CZEN.org. The vision of these CI initiatives is to provide cyber-enhanced portals that encourage domain scientists to upload their data before publication (in private cyberspace), and to make these data eventually publicly accessible (after an embargo period). If the CI can be made to provide services to the domain specialist - e.g. to provide data analysis services or data comparison services - we envision that scientists will upload data. In addition, the CI can promote the use and comparison of datasets across disciplines. For example, the CI can facilitate the use of spatially indexed geochemical data by scientists more accustomed to dealing with time-course data for hydrologic flow, and can provide user-friendly interfaces with CI established to facilitate the use of hydrologic data. Examples of the usage of synthesized data to predict soil development over the last 13ky and its effects on active hydrological flow boundaries in surficial systems will be discussed for i) a N

Optimal transportation networks models and theory

CERN Document Server

Bernot, Marc; Morel, Jean-Michel

2009-01-01

The transportation problem can be formalized as the problem of finding the optimal way to transport a given measure into another with the same mass. In contrast to the Monge-Kantorovitch problem, recent approaches model the branched structure of such supply networks as minima of an energy functional whose essential feature is to favour wide roads. Such a branched structure is observable in ground transportation networks, in draining and irrigation systems, in electrical power supply systems and in natural counterparts such as blood vessels or the branches of trees. These lectures provide mathematical proof of several existence, structure and regularity properties empirically observed in transportation networks. The link with previous discrete physical models of irrigation and erosion models in geomorphology and with discrete telecommunication and transportation models is discussed. It will be mathematically proven that the majority fit in the simple model sketched in this volume.

Identification of the Hydrogeochemical Processes in Groundwater Using Classic Integrated Geochemical Methods and Geostatistical Techniques, in Amol-Babol Plain, Iran

Science.gov (United States)

Sheikhy Narany, Tahoora; Ramli, Mohammad Firuz; Aris, Ahmad Zaharin; Sulaiman, Wan Nor Azmin; Juahir, Hafizan; Fakharian, Kazem

2014-01-01

Hydrogeochemical investigations had been carried out at the Amol-Babol Plain in the north of Iran. Geochemical processes and factors controlling the groundwater chemistry are identified based on the combination of classic geochemical methods with geographic information system (GIS) and geostatistical techniques. The results of the ionic ratios and Gibbs plots show that water rock interaction mechanisms, followed by cation exchange, and dissolution of carbonate and silicate minerals have influenced the groundwater chemistry in the study area. The hydrogeochemical characteristics of groundwater show a shift from low mineralized Ca-HCO3, Ca-Na-HCO3, and Ca-Cl water types to high mineralized Na-Cl water type. Three classes, namely, C1, C2, and C3, have been classified using cluster analysis. The spatial distribution maps of Na+/Cl−, Mg2+/Ca2+, and Cl−/HCO3 − ratios and electrical conductivity values indicate that the carbonate and weathering of silicate minerals played a significant role in the groundwater chemistry on the southern and western sides of the plain. However, salinization process had increased due to the influence of the evaporation-precipitation process towards the north-eastern side of the study area. PMID:24523640

Dileptons from transport and hydrodynamical models

International Nuclear Information System (INIS)

Huovinen, P.; Koch, V.

2000-01-01

Transport and hydrodynamical models used to describe the expansion stage of a heavy-ion collision at the CERN SPS give different dilepton spectrum even if they are tuned to reproduce the observed hadron spectra. To understand the origin of this difference we compare the dilepton emission from transport and hydrodynamical models using similar initial states in both models. We find that the requirement of pion number conservation in a hydrodynamical model does not change the dilepton emission. Also the mass distribution from the transport model indicates faster cooling and longer lifetime of the fireball

Assessment of applications of transport models on regional scale solute transport

Science.gov (United States)

Guo, Z.; Fogg, G. E.; Henri, C.; Pauloo, R.

2017-12-01

Regional scale transport models are needed to support the long-term evaluation of groundwater quality and to develop management strategies aiming to prevent serious groundwater degradation. The purpose of this study is to evaluate the capacity of previously-developed upscaling approaches to accurately describe main solute transport processes including the capture of late-time tails under changing boundary conditions. Advective-dispersive contaminant transport in a 3D heterogeneous domain was simulated and used as a reference solution. Equivalent transport under homogeneous flow conditions were then evaluated applying the Multi-Rate Mass Transfer (MRMT) model. The random walk particle tracking method was used for both heterogeneous and homogeneous-MRMT scenarios under steady state and transient conditions. The results indicate that the MRMT model can capture the tails satisfactorily for plume transported with ambient steady-state flow field. However, when boundary conditions change, the mass transfer model calibrated for transport under steady-state conditions cannot accurately reproduce the tailing effect observed for the heterogeneous scenario. The deteriorating impact of transient boundary conditions on the upscaled model is more significant for regions where flow fields are dramatically affected, highlighting the poor applicability of the MRMT approach for complex field settings. Accurately simulating mass in both mobile and immobile zones is critical to represent the transport process under transient flow conditions and will be the future focus of our study.

Mathematical modeling plasma transport in tokamaks

Energy Technology Data Exchange (ETDEWEB)

Quiang, Ji [Univ. of Illinois, Urbana-Champaign, IL (United States)

1997-01-01

In this work, the author applied a systematic calibration, validation and application procedure based on the methodology of mathematical modeling to international thermonuclear experimental reactor (ITER) ignition studies. The multi-mode plasma transport model used here includes a linear combination of drift wave branch and ballooning branch instabilities with two a priori uncertain constants to account for anomalous plasma transport in tokamaks. A Bayesian parameter estimation method is used including experimental calibration error/model offsets and error bar rescaling factors to determine the two uncertain constants in the transport model with quantitative confidence level estimates for the calibrated parameters, which gives two saturation levels of instabilities. This method is first tested using a gyroBohm multi-mode transport model with a pair of DIII-D discharge experimental data, and then applied to calibrating a nominal multi-mode transport model against a broad database using twelve discharges from seven different tokamaks. The calibrated transport model is then validated on five discharges from JT-60 with no adjustable constants. The results are in a good agreement with experimental data. Finally, the resulting class of multi-mode tokamak plasma transport models is applied to the transport analysis of the ignition probability in a next generation machine, ITER. A reference simulation of basic ITER engineering design activity (EDA) parameters shows that a self-sustained thermonuclear burn with 1.5 GW output power can be achieved provided that impurity control makes radiative losses sufficiently small at an average plasma density of 1.2 X 10²⁰/m³ with 50 MW auxiliary heating. The ignition probability of ITER for the EDA parameters, can be formally as high as 99.9% in the present context. The same probability for concept design activity (CDA) parameters of ITER, which has smaller size and lower current, is only 62.6%.

Mathematical modeling plasma transport in tokamaks

International Nuclear Information System (INIS)

Quiang, Ji

1995-01-01

In this work, the author applied a systematic calibration, validation and application procedure based on the methodology of mathematical modeling to international thermonuclear experimental reactor (ITER) ignition studies. The multi-mode plasma transport model used here includes a linear combination of drift wave branch and ballooning branch instabilities with two a priori uncertain constants to account for anomalous plasma transport in tokamaks. A Bayesian parameter estimation method is used including experimental calibration error/model offsets and error bar rescaling factors to determine the two uncertain constants in the transport model with quantitative confidence level estimates for the calibrated parameters, which gives two saturation levels of instabilities. This method is first tested using a gyroBohm multi-mode transport model with a pair of DIII-D discharge experimental data, and then applied to calibrating a nominal multi-mode transport model against a broad database using twelve discharges from seven different tokamaks. The calibrated transport model is then validated on five discharges from JT-60 with no adjustable constants. The results are in a good agreement with experimental data. Finally, the resulting class of multi-mode tokamak plasma transport models is applied to the transport analysis of the ignition probability in a next generation machine, ITER. A reference simulation of basic ITER engineering design activity (EDA) parameters shows that a self-sustained thermonuclear burn with 1.5 GW output power can be achieved provided that impurity control makes radiative losses sufficiently small at an average plasma density of 1.2 X 10 20 /m 3 with 50 MW auxiliary heating. The ignition probability of ITER for the EDA parameters, can be formally as high as 99.9% in the present context. The same probability for concept design activity (CDA) parameters of ITER, which has smaller size and lower current, is only 62.6%

A disaggregate freight transport model of transport chain and shipment size choice

NARCIS (Netherlands)

Windisch, E.; De Jong, G.C.; Van Nes, R.; Hoogendoorn, S.P.

2010-01-01

The field of freight transport modelling is relatively young compared to passenger transport modelling. However, some key issues in freight policy, like growing freight shares on the road, advanced logistics concepts or emerging strict freight transport regulations, have been creating increasing

System Convergence in Transport Modelling

DEFF Research Database (Denmark)

Rich, Jeppe; Nielsen, Otto Anker; Cantarella, Guilio E.

2010-01-01

A fundamental premise of most applied transport models is the existence and uniqueness of an equilibrium solution that balances demand x(t) and supply t(x). The demand consists of the people that travel in the transport system and on the defined network, whereas the supply consists of the resulting...... level-of-service attributes (e.g., travel time and cost) offered to travellers. An important source of complexity is the congestion, which causes increasing demand to affect travel time in a non-linear way. Transport models most often involve separate models for traffic assignment and demand modelling...... iterating between a route-choice (demand) model and a time-flow (supply) model. It is generally recognised that a simple iteration scheme where the level-of-service level is fed directly to the route-choice and vice versa may exhibit an unstable pattern and lead to cyclic unstable solutions. It can be shown...

Modeling pollutant transport using a meshless-lagrangian particle model

International Nuclear Information System (INIS)

Carrington, D.B.; Pepper, D.W.

2002-01-01

A combined meshless-Lagrangian particle transport model is used to predict pollutant transport over irregular terrain. The numerical model for initializing the velocity field is based on a meshless approach utilizing multiquadrics established by Kansa. The Lagrangian particle transport technique uses a random walk procedure to depict the advection and dispersion of pollutants over any type of surface, including street and city canyons

Uncertainty calculation in transport models and forecasts

DEFF Research Database (Denmark)

Manzo, Stefano; Prato, Carlo Giacomo

Transport projects and policy evaluations are often based on transport model output, i.e. traffic flows and derived effects. However, literature has shown that there is often a considerable difference between forecasted and observed traffic flows. This difference causes misallocation of (public...... implemented by using an approach based on stochastic techniques (Monte Carlo simulation and Bootstrap re-sampling) or scenario analysis combined with model sensitivity tests. Two transport models are used as case studies: the Næstved model and the Danish National Transport Model. 3 The first paper...... in a four-stage transport model related to different variable distributions (to be used in a Monte Carlo simulation procedure), assignment procedures and levels of congestion, at both the link and the network level. The analysis used as case study the Næstved model, referring to the Danish town of Næstved2...

Highway and interline transportation routing models

International Nuclear Information System (INIS)

Joy, D.S.; Johnson, P.E.

1994-01-01

The potential impacts associated with the transportation of hazardous materials are important issues to shippers, carriers, and the general public. Since transportation routes are a central characteristic in most of these issues, the prediction of likely routes is the first step toward the resolution of these issues. In addition, US Department of Transportation requirements (HM-164) mandate specific routes for shipments of highway controlled quantities of radioactive materials. In response to these needs, two routing models have been developed at Oak Ridge National Laboratory under the sponsorship of the U.S. Department of Energy (DOE). These models have been designated by DOE's Office of Environmental Restoration and Waste Management, Transportation Management Division (DOE/EM) as the official DOE routing models. Both models, HIGHWAY and INTERLINE, are described

Up-gradient transport in a probabilistic transport model

DEFF Research Database (Denmark)

Gavnholt, J.; Juul Rasmussen, J.; Garcia, O.E.

2005-01-01

The transport of particles or heat against the driving gradient is studied by employing a probabilistic transport model with a characteristic particle step length that depends on the local concentration or heat gradient. When this gradient is larger than a prescribed critical value, the standard....... These results supplement recent works by van Milligen [Phys. Plasmas 11, 3787 (2004)], which applied Levy distributed step sizes in the case of supercritical gradients to obtain the up-gradient transport. (c) 2005 American Institute of Physics....

Modelling of radon transport in porous media

NARCIS (Netherlands)

van der Graaf, E.R.; de Meijer, R.J.; Katase, A; Shimo, M

1998-01-01

This paper aims to describe the state of the art of modelling radon transport in soil on basis of multiphase radon transport equations. Emphasis is given to methods to obtain a consistent set of input parameters needed For such models. Model-measurement comparisons with the KVI radon transport

Monte Carlo impurity transport modeling in the DIII-D transport

International Nuclear Information System (INIS)

Evans, T.E.; Finkenthal, D.F.

1998-04-01

A description of the carbon transport and sputtering physics contained in the Monte Carlo Impurity (MCI) transport code is given. Examples of statistically significant carbon transport pathways are examined using MCI's unique tracking visualizer and a mechanism for enhanced carbon accumulation on the high field side of the divertor chamber is discussed. Comparisons between carbon emissions calculated with MCI and those measured in the DIII-D tokamak are described. Good qualitative agreement is found between 2D carbon emission patterns calculated with MCI and experimentally measured carbon patterns. While uncertainties in the sputtering physics, atomic data, and transport models have made quantitative comparisons with experiments more difficult, recent results using a physics based model for physical and chemical sputtering has yielded simulations with about 50% of the total carbon radiation measured in the divertor. These results and plans for future improvement in the physics models and atomic data are discussed

Coal supply and transportation model (CSTM)

International Nuclear Information System (INIS)

1991-11-01

The Coal Supply and Transportation Model (CSTM) forecasts annual coal supply and distribution to domestic and foreign markets. The model describes US coal production, national and international coal transportation industries. The objective of this work is to provide a technical description of the current version of the model

Transport Choice Modeling for the Evaluation of New Transport Policies

Directory of Open Access Journals (Sweden)

Ander Pijoan

2018-04-01

Full Text Available Quantifying the impact of the application of sustainable transport policies is essential in order to mitigate effects of greenhouse gas emissions produced by the transport sector. One of the most common approaches used for this purpose is that of traffic modelling and simulation, which consists of emulating the operation of an entire road network. This article presents the results of fitting 8 well known data science methods for transport choice modelling, the area in which more research is needed. The models have been trained with information from Biscay province in Spain in order to match as many of its commuters as possible. Results show that the best models correctly forecast more than 51% of the trips recorded. Finally, the results have been validated with a second data set from the Silesian Voivodeship in Poland, showing that all models indeed maintain their forecasting ability.

Radioactive hydrogeochemical processes in the Chihuahua-Sacramento Basin, Mexico

Energy Technology Data Exchange (ETDEWEB)

Burillo, J. C.; Reyes C, M.; Montero C, M. E.; Renteria V, M.; Herrera P, E. F. [Centro de Investigacion en Materiales Avanzados, S. C., Miguel de Cervantes No. 120, Complejo Industrial Chihuahua, 31109 Chihuahua (Mexico); Reyes, I.; Espino, M. S., E-mail: elena.montero@cimav.edu.mx [Universidad Autonoma de Chihuahua, Facultad de Ingenieria, Nuevo Campus Universitario, Chihuahua (Mexico)

2012-06-15

The Chihuahua Basin is divided by its morphology into three main sub basins: Chihuahua-Sacramento sub basin, Chihuahua Dam sub basin and Chuviscar River sub basin. In the aquifers at the Sacramento sub basin, specific concentrations of uranium in groundwater range from 460 to 1260 Bq / m{sup 3}. The presence of strata and sandy clay lenses with radiometric anomalies in the N W of Chihuahua Valley was confirmed by a litostatigraphic study and gamma spectrometry measurements of drill cuttings. High uranium activity values found in the water of some deep wells may correspond to the presence of fine material bodies of carbonaceous material, possible forming pa leo-sediment of flooding or pa leo-soils. It is suggested that these clay horizons are uranyl ion collectors. Uranyl may suffer a reduction process by organic material. Furthermore the groundwater, depending on its ph and Eh, oxidizes and re-dissolves uranium. The hydrogeochemical behavior of San Marcos dam and the N W Valley area is the subject of studies that should help to clarify the origin of the radioactive elements and their relationships with other pollutants in the watershed. (Author)

Radioactive hydrogeochemical processes in the Chihuahua-Sacramento Basin, Mexico

International Nuclear Information System (INIS)

Burillo, J. C.; Reyes C, M.; Montero C, M. E.; Renteria V, M.; Herrera P, E. F.; Reyes, I.; Espino, M. S.

2012-01-01

The Chihuahua Basin is divided by its morphology into three main sub basins: Chihuahua-Sacramento sub basin, Chihuahua Dam sub basin and Chuviscar River sub basin. In the aquifers at the Sacramento sub basin, specific concentrations of uranium in groundwater range from 460 to 1260 Bq / m 3 . The presence of strata and sandy clay lenses with radiometric anomalies in the N W of Chihuahua Valley was confirmed by a litostatigraphic study and gamma spectrometry measurements of drill cuttings. High uranium activity values found in the water of some deep wells may correspond to the presence of fine material bodies of carbonaceous material, possible forming pa leo-sediment of flooding or pa leo-soils. It is suggested that these clay horizons are uranyl ion collectors. Uranyl may suffer a reduction process by organic material. Furthermore the groundwater, depending on its ph and Eh, oxidizes and re-dissolves uranium. The hydrogeochemical behavior of San Marcos dam and the N W Valley area is the subject of studies that should help to clarify the origin of the radioactive elements and their relationships with other pollutants in the watershed. (Author)

Biological transportation networks: Modeling and simulation

KAUST Repository

Albi, Giacomo; Artina, Marco; Foransier, Massimo; Markowich, Peter A.

2015-01-01

We present a model for biological network formation originally introduced by Cai and Hu [Adaptation and optimization of biological transport networks, Phys. Rev. Lett. 111 (2013) 138701]. The modeling of fluid transportation (e.g., leaf venation

RADIONUCLIDE TRANSPORT MODELS UNDER AMBIENT CONDITIONS

Energy Technology Data Exchange (ETDEWEB)

S. Magnuson

2004-11-01

The purpose of this model report is to document the unsaturated zone (UZ) radionuclide transport model, which evaluates, by means of three-dimensional numerical models, the transport of radioactive solutes and colloids in the UZ, under ambient conditions, from the repository horizon to the water table at Yucca Mountain, Nevada.

Hydrogeochemical and Isotopic Study of Groundwaters from the Gañuelas-Mazarrón Tertiary Basin (Murcia, Spain); Estudio Hidrogeoquímico e Isotópico de las Aguas de la Cuenca Terciaria de Gañuelas-Mazarrón (Murcia, España)

Energy Technology Data Exchange (ETDEWEB)

Rodrigo-Naharro, J.; Delgado, A.; Clemente-Jul, C.; Pérez del Villar, L.

2015-07-01

The hydrogeochemical characterisation of groundwaters from the Gañuelas-Mazarrón Tertiary Basin included: i) to establish the different hydrofacies present in the basin; ii) to perform a cluster analysis in order to reduce the water samples, grouping them according to their physicochemical characteristics; and iii) to determine the most relevant ion ratios for understanding the water/ rock interaction processes that regulate the main features and evolution of groundwaters. It has also been discussed the origin and concentration of the minor and trace elements to evaluate the capability of groundwaters to transport heavy elements, toxic or innocuous, towards the surface, thus determining their suitability for human consumption. Besides, the hydrogeochemical modeling has allowed determining the degree of groundwaters saturation with respect to the most representative mineral phases of the aquifers, which, in turn, it has been used to calculate their theoretical temperature in depth. The isotopic characterisation of groundwaters has included the isotopic signatures of the stable (δ18O, δ2H, δ13C-DIC, δ34S(SO4 2-) and δ18O(SO4 2-)) and radioactive (238U, 234U and 226Ra) isotopes. The first have been used to distinguish the groundwaters origin, as well as the origin of the dissolved C and SO4 2-. The radioactive isotopes have been used to determine the water/rock interaction processes involving 238U radioactive series, as well as to explain the origin of the dissolved 222Rn in groundwaters. The most important hydrogeochemical results obtained from groundwaters are: i) a large variety of hydrofacies is represented in them, corroborated by the cluster analysis; ii) they are not suitable for human consumption; iii) they have remained, apparently, over-saturated with respect to calcite and aragonite, and under-saturated with respect to gypsum, anhydrite and halite, over time; iv) they present theoretical temperatures in depth much higher than in the surface; v) they

An exploration hydrogeochemical study at the giant Pebble porphyry Cu-Au-Mo deposit, Alaska, USA, using high-resolution ICP-MS

Science.gov (United States)

Eppinger, Robert G.; Fey, David L.; Giles, Stuart A.; Kelley, Karen D.; Smith, Steven M.

2012-01-01

A hydrogeochemical study using high resolution ICP-MS was undertaken at the giant Pebble porphyry Cu-Au-Mo deposit and surrounding mineral occurrences. Surface water and groundwater samples from regional background and the deposit area were collected at 168 sites. Rigorous quality control reveals impressive results at low nanogram per litre (ng/l) levels. Sites with pH values below 5.1 are from ponds in the Pebble West area, where sulphide-bearing rubble crop is thinly covered. Relative to other study area waters, anomalous concentrations of Cu, Cd, K, Ni, Re, the REE, Tl, SO42− and F− are present in water samples from Pebble West. Samples from circum-neutral waters at Pebble East and parts of Pebble West, where cover is much thicker, have anomalous concentrations of Ag, As, In, Mn, Mo, Sb, Th, U, V, and W. Low-level anomalous concentrations for most of these elements were also found in waters surrounding nearby porphyry and skarn mineral occurrences. Many of these elements are present in low ng/l concentration ranges and would not have been detected using traditional quadrupole ICP-MS. Hydrogeochemical exploration paired with high resolution ICP-MS is a powerful new tool in the search for concealed deposits.

Hydrogeochemical and stream sediment sampling for uranium in the sandstone environment

International Nuclear Information System (INIS)

Wenrich, K.J.

1985-01-01

Sandstone terranes commonly host uranium occurrences in the western United States. In addition, because sedimentary terranes, particularly shales and immature, not well cemented sandstone, contribute more sediment and soluble material than do plutonic, volcanic, or metamorphic terranes they are an excellent regime for hydrogeochemical and stream-sediment prospecting. Because of higher conductivity, and hence higher uranium content, of waters draining such environments the sampling need not be as precise nor the analytical detection limit as low as in other terranes to yield a successful survey. Nevertheless, reasonable preparation and care of the samples is recommended: (1) The water samples should be filtered through 0.45 μm membranes and acidified to a pH of less than 1. (2) Because the adsorption of uranium by organic material is so significant it is recommended that the reasonable finest stream-sediment fraction, 4 , conductivity, etc.) are useful in the data reduction towards the elimination of false anomalies. (author)

Electronic transport in VO{sub 2}—Experimentally calibrated Boltzmann transport modeling

Energy Technology Data Exchange (ETDEWEB)

Kinaci, Alper; Rosenmann, Daniel; Chan, Maria K. Y., E-mail: debasish.banerjee@toyota.com, E-mail: mchan@anl.gov [Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Kado, Motohisa [Higashifuji Technical Center, Toyota Motor Corporation, Susono, Shizuoka 410-1193 (Japan); Ling, Chen; Zhu, Gaohua; Banerjee, Debasish, E-mail: debasish.banerjee@toyota.com, E-mail: mchan@anl.gov [Materials Research Department, Toyota Motor Engineering and Manufacturing North America, Inc., Ann Arbor, Michigan 48105 (United States)

2015-12-28

Materials that undergo metal-insulator transitions (MITs) are under intense study, because the transition is scientifically fascinating and technologically promising for various applications. Among these materials, VO{sub 2} has served as a prototype due to its favorable transition temperature. While the physical underpinnings of the transition have been heavily investigated experimentally and computationally, quantitative modeling of electronic transport in the two phases has yet to be undertaken. In this work, we establish a density-functional-theory (DFT)-based approach with Hubbard U correction (DFT + U) to model electronic transport properties in VO{sub 2} in the semiconducting and metallic regimes, focusing on band transport using the Boltzmann transport equations. We synthesized high quality VO{sub 2} films and measured the transport quantities across the transition, in order to calibrate the free parameters in the model. We find that the experimental calibration of the Hubbard correction term can efficiently and adequately model the metallic and semiconducting phases, allowing for further computational design of MIT materials for desirable transport properties.

Cumulus parameterizations in chemical transport models

Science.gov (United States)

Mahowald, Natalie M.; Rasch, Philip J.; Prinn, Ronald G.

1995-12-01

Global three-dimensional chemical transport models (CTMs) are valuable tools for studying processes controlling the distribution of trace constituents in the atmosphere. A major uncertainty in these models is the subgrid-scale parametrization of transport by cumulus convection. This study seeks to define the range of behavior of moist convective schemes and point toward more reliable formulations for inclusion in chemical transport models. The emphasis is on deriving convective transport from meteorological data sets (such as those from the forecast centers) which do not routinely include convective mass fluxes. Seven moist convective parameterizations are compared in a column model to examine the sensitivity of the vertical profile of trace gases to the parameterization used in a global chemical transport model. The moist convective schemes examined are the Emanuel scheme [Emanuel, 1991], the Feichter-Crutzen scheme [Feichter and Crutzen, 1990], the inverse thermodynamic scheme (described in this paper), two versions of a scheme suggested by Hack [Hack, 1994], and two versions of a scheme suggested by Tiedtke (one following the formulation used in the ECMWF (European Centre for Medium-Range Weather Forecasting) and ECHAM3 (European Centre and Hamburg Max-Planck-Institut) models [Tiedtke, 1989], and one formulated as in the TM2 (Transport Model-2) model (M. Heimann, personal communication, 1992). These convective schemes vary in the closure used to derive the mass fluxes, as well as the cloud model formulation, giving a broad range of results. In addition, two boundary layer schemes are compared: a state-of-the-art nonlocal boundary layer scheme [Holtslag and Boville, 1993] and a simple adiabatic mixing scheme described in this paper. Three tests are used to compare the moist convective schemes against observations. Although the tests conducted here cannot conclusively show that one parameterization is better than the others, the tests are a good measure of the

Modelling radionuclide transport in the geosphere: a review of the models available

International Nuclear Information System (INIS)

Cacas, M.C.; Cordier, E.; Coudrain-Ribstein, A.; Fargue, D.; Goblet, P.; Jamet, Ph.; Ledoux, E.; Marsily, G. de; Vinsot, A.; Brun, Ch.; Cernes, A.; Jacquier, Ph.; Lewi, J.; Priem, Th.

1990-01-01

Over the last twelve years, several models have been developed to simulate the transport of radionuclides in the environment of a radioactive waste repository: - continuous equivalent porous media flow and transport models using the finite element method in 1, 2 or 3 dimensions and taking into account various coupled mechanisms; - discontinuous stochastic fracture network models in 3 dimensions representing flow, transport, matrix diffusion, heat flow and mechanical stress; - geochemical models representing interactions between transported elements and a solid matrix; - transport process models coupling non dominant phenomena such as thermo-diffusion or thermo-gravitation. This paper reviews the role that each of these models can play in safety analyses. 3 refs [fr

Methods for testing transport models

International Nuclear Information System (INIS)

Singer, C.; Cox, D.

1993-01-01

This report documents progress to date under a three-year contract for developing ''Methods for Testing Transport Models.'' The work described includes (1) choice of best methods for producing ''code emulators'' for analysis of very large global energy confinement databases, (2) recent applications of stratified regressions for treating individual measurement errors as well as calibration/modeling errors randomly distributed across various tokamaks, (3) Bayesian methods for utilizing prior information due to previous empirical and/or theoretical analyses, (4) extension of code emulator methodology to profile data, (5) application of nonlinear least squares estimators to simulation of profile data, (6) development of more sophisticated statistical methods for handling profile data, (7) acquisition of a much larger experimental database, and (8) extensive exploratory simulation work on a large variety of discharges using recently improved models for transport theories and boundary conditions. From all of this work, it has been possible to define a complete methodology for testing new sets of reference transport models against much larger multi-institutional databases

Uranium hydrogeochemical and stream sediment reconnaissance of the Valdez NTMS Quadrangle, Alaska

Energy Technology Data Exchange (ETDEWEB)

1981-05-01

This report presents results of a Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) of the Valdez NTMS quadrangle, Alaska. In addition to this abbreviated data release, more complete data are available to the public in machine-readable form through the Grand Junction Office Information System (GJOIS) at Oak Ridge National Laboratory (ORNL). Presented in this data release are location data, field analyses, and laboratory analyses of several different sample media. For the sake of brevity, many field site observations have not been included in this volume. These data are, however, available on the magnetic tape. Appendices A to D describe the sample media and summarize the analytical results for each medium. The data were subsetted by one of the Los Alamos National Laboratory (LANL) sorting programs of Zinkl and others (1981a) into groups of stream sediment, lake sediment, stream water, lake water, and ground water samples.

Uranium hydrogeochemical and stream sediment reconnaissance of the Chandalar NTMS quadrangle, Alaska

International Nuclear Information System (INIS)

1981-09-01

Results of a hydrogeochemical and stream sediment reconnaissance of the Chandalar NTMS quadrangle, Alaska are presented. In addition to this abbreviated data release, more complete data are available to the public in machine-readable form. In this data release are location data, field analyses, and laboratory analyses of several different sample media. For the sake of brevity, may field site observations have not been included in this volume. These data are, however, available on the magnetic tape. Appendices A and B describe the sample media and summarize the analytical results for each medium. The data were subsetted by one of the Los Alamos National Laboratory (LANL) sorting programs into groups of stream sediment and lake sediment samples. For each group which contains a sufficient number of observations, statistical tables, tables of raw data, and 1:1000000 scale maps of pertinent elements have been included in this report

Evaluation of Groundwater for Arsenic Contamination Using Hydrogeochemical Properties and Multivariate Statistical Methods in Saudi Arabia

Directory of Open Access Journals (Sweden)

Abdullah S. Al-Farraj

2013-01-01

Full Text Available The aim of this research is to evaluate arsenic distribution and associated hydrogeochemical parameters in 27 randomly selected boreholes representing aquifers in the Al-Kharj geothermal fields of Saudi Arabia. Arsenic was detected at all sites, with 92.5% of boreholes yielding concentrations above the WHO permissible limit of 10 μg/L. The maximum concentration recorded was 122 μg/L (SD = 29 μg/L skewness = 1.87. The groundwater types were mainly Ca+2-Mg+2-SO4-2-Cl− and Na+-Cl−-SO4-2, accounting for 67% of the total composition. Principal component analysis (PCA showed that the main source of arsenic release was geothermal in nature and was linked to processes similar to those involved in the release of boron. The PCA yielded five components, which accounted for 44.1%, 17.0%, 10.1%, 08.4%, and 06.5% of the total variance. The first component had positive loadings for arsenic and boron along with other hydrogeochemical parameters, indicating the primary sources of As mobilization are derived from regional geothermal systems and weathering of minerals. The remaining principal components indicated reductive dissolution of iron oxyhydroxides as a possible mechanism. Spatial evaluation of the PCA results indicated that this secondary mechanism of arsenic mobilization may be active and correlates positively with total organic carbon. The aquifers were found to be contaminated to a high degree with organic carbon ranging from 0.57 mg/L to 21.42 mg/L and showed high concentrations of NO3- ranging from 8.05 mg/L to 248.2 mg/L.

Hydrogeochemical attributes and ground water quality of Ngbo Community in Ohaukwu Area Council, Ebonyi State, Nigeria

Directory of Open Access Journals (Sweden)

Omaka Ndukaku Omaka

2015-01-01

Full Text Available This study evaluated the hydrogeochemical attributes and quality of groundwater resources in Ngbo, Ohaukwu Area Council of Ebonyi State, Nigeria in order to determine whether boreholes in the area were suitable for potable uses. Eleven groundwater samples were collected from hand-dug boreholes between February and March, 2013. The physiochemical parameters of the samples were then analyzed to determine electrical conductivity, total dissolved solids, total alkalinity, major cations and anions, and trace metals. The quality of these characteristics was evaluated by comparing them to the Nigerian Institute of Standards, the Bureau of Indian Standards and the World Health Organization standards for drinking water quality. Mass abundance of the major ions was in the order of Mg2+ > Ca2+ for cations, Cl- > SO4 2 - > NO3 - > PO4 3 - for anions and Fe > As > Mn > Cu > Zn > Cr > Ni > Pb > Cd for trace metals. Correlation analysis revealed both positive and negative correlations among the parameters. Also, one-way ANOVA tests revealed that no significant differences existed between physiochemical parameters (F = 1.004 < Fcrit =1.977, major cations and anions (F =0.547 < Fcrit =2.008 and trace metals (F = 0.772 < Fcrit = 1.940 regardless of the sampling location. Groundwater in the area was generally hard, alkaline and highly mineralized, making it unsuitable for drinking in some places due to high total hardness and TDS; but it was generally suitable for irrigation purposes. It is recommended that boreholes be flushed regularly to aid in the removal of mineralized deposits, and that regular hydrogeochemical studies be conducted in order to detect future deterioration of water quality

Modelling dust transport in tokamaks

International Nuclear Information System (INIS)

Martin, J.D.; Martin, J.D.; Bacharis, M.; Coppins, M.; Counsell, G.F.; Allen, J.E.; Counsell, G.F.

2008-01-01

The DTOKS code, which models dust transport through tokamak plasmas, is described. The floating potential and charge of a dust grain in a plasma and the fluxes of energy to and from it are calculated. From this model, the temperature of the dust grain can be estimated. A plasma background is supplied by a standard tokamak edge modelling code (B2SOLPS5.0), and dust transport through MAST (the Mega-Amp Spherical Tokamak) and ITER plasmas is presented. We conclude that micron-radius tungsten dust can reach the separatrix in ITER. (authors)

The european Trans-Tools transport model

NARCIS (Netherlands)

Rooijen, T. van; Burgess, A.

2008-01-01

The paper presents the use of ArcGIS in the Transtools Transport Model, TRANS-TOOLS, created by an international consortium for the European Commission. The model describe passenger as well as freight transport in Europe with all medium and long distance modes (cars, vans, trucks, train, inland

Two-point model for divertor transport

International Nuclear Information System (INIS)

Galambos, J.D.; Peng, Y.K.M.

1984-04-01

Plasma transport along divertor field lines was investigated using a two-point model. This treatment requires considerably less effort to find solutions to the transport equations than previously used one-dimensional (1-D) models and is useful for studying general trends. It also can be a valuable tool for benchmarking more sophisticated models. The model was used to investigate the possibility of operating in the so-called high density, low temperature regime

A Mercury Model of Atmospheric Transport

Energy Technology Data Exchange (ETDEWEB)

Christensen, Alex B. [Oregon State Univ., Corvallis, OR (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chodash, Perry A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Procassini, R. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2018-01-19

Using the particle transport code Mercury, accurate models were built of the two sources used in Operation BREN, a series of radiation experiments performed by the United States during the 1960s. In the future, these models will be used to validate Mercury’s ability to simulate atmospheric transport.

Relationship between tectonic structures and hydrogeochemical compartmentalization in aquifers: Example of the “Jeffara de Medenine” system, south–east Tunisia

Directory of Open Access Journals (Sweden)

Hayet Chihi

2015-09-01

The kriged maps of major-ion concentrations and of total dissolved solids in the aquifers were then analyzed and compared with the reservoir facies distribution for each compartment, the geometric characteristics of the aquifer, and the piezometric level trends. This allowed to characterize the hydraulic behavior of the Medenine fault and to understand the underlying physical and chemical processes having led to the spatial distribution of the geochemical properties, and thus, the hydrogeochemical functioning of the aquifers.

Investigation research on the evaluation of a coupled thermo-hydro-mechanical-chemical phenomena. Outline report

International Nuclear Information System (INIS)

Chijimatsu, Masakazu; Amemiya, Kiyoshi; Neyama, Atsushi; Iwata, Hiroshi; Nakagawa, Koichi; Ishihara, Yoshinao; Shiozaki, Isao; Sagawa, Hiroshi

2002-02-01

In order to realize a coupling analysis in the near field of the geological disposal system, this study has been studied on the addition of the mass transport model to the coupled thermo-hydro-mechanical analysis code (THAMES) and preliminary coupling analysis by using development environmental tool (Diffpack) for numerical analysis. (1) In order to prepare the strategy on the addition of the mass transport model to the coupled thermo-hydro-mechanical analysis code (THAMES), we have studied on the requirement of THAMES-Transport and methodology of coupling analysis. After that we set out modification plan by the Eulerian-Lagrangian (EL) method. (2) Based on the document of modification plan, we have done addition of the mass transport model to the coupled thermo-hydro-mechanical analysis code (THAMES) and carried out verification analysis in order to confirm on the accuracy of THAMES-Transport. (3) In order to understand on the behavior of NaCl in the porewater under the coupled thermo-hydro-mechanical phenomena in the HLW engineered barrier system, we have calculated coupling phenomenon by using THAMES-Transport. Transportation and concentration phenomena of NaCl are calculated but precipitation of NaCl is not occurred under the analysis conditions in this report. (4) In order to confirm about feasibility of coupling analysis under the development environmental tool (Diffpack) for numerical analysis, we have carried out on the design work and writing program of the preliminary coupling system. In this study, we have adopted existing transport model (HYDROGEOCHEM) and geochemical model (phreeqe60) for preliminary coupling system. (5) In order to confirm program correctness of preliminary coupling system, we have carried out benchmarking analysis by using existing reactive-transport analysis code (HYDROGEOCHEM). (6) We have been prepared short-range development plan based on through the modification study of THAMES and writing program of the preliminary coupling

Investigation research on the evaluation of a coupled thermo-hydro-mechanical-chemical phenomena. Result report

International Nuclear Information System (INIS)

Chijimatsu, Masakazu; Amemiya, Kiyoshi; Shiozaki, Isao; Neyama, Atsushi; Iwata, Hiroshi; Nakagawa, Koichi; Ishihara, Yoshinao; Sagawa, Hiroshi

2002-02-01

In order to realize a coupling analysis in the near field of the geological disposal system, this study has been studied on the addition of the mass transport model to the coupled thermo-hydro-mechanical analysis code (THAMES) and preliminary coupling analysis by using development environmental tool (Diffpack) for numerical analysis. (1) In order to prepare the strategy on the addition of the mass transport model to the coupled thermo-hydro-mechanical analysis code (THAMES), we have studied on the requirement of THAMES-Transport and methodology of coupling analysis. After that we set out modification plan by the Eulerian-Lagrangian (EL) method. (2) Based on the document of modification plan, we have done addition of the mass transport model to the coupled thermo-hydro-mechanical analysis code (THAMES) and carried out verification analysis in order to confirm on the accuracy of THAMES-Transport. (3) In order to understand on the behavior of NaCl in the porewater under the coupled thermo-hydro-mechanical phenomena in the HLW engineered barrier system, we have calculated coupling phenomenon by using THAMES-Transport. Transportation and concentration phenomena of NaCl are calculated but precipitation of NaCl is not occurred under the analysis conditions in this report. (4) In order to confirm about feasibility of coupling analysis under the development environmental tool (Diffpack) for numerical analysis, we have carried out on the design work and writing program of the preliminary coupling system. In this study, we have adopted existing transport model (HYDROGEOCHEM) and geochemical model (phreeqe 60) for preliminary coupling system. (5) In order to confirm program correctness of preliminary coupling system, we have carried out benchmarking analysis by using existing reactive-transport analysis code (HYDROGEOCHEM). (6) We have been prepared short-range development plan based on through the modification study of THAMES and writing program of the preliminary coupling

Solute transport in coupled inland-coastal water systems. General conceptualisation and application to Forsmark

International Nuclear Information System (INIS)

Jarsjoe, Jerker; Destouni, Georgia; Persson, Klas; Prieto, Carmen

2007-12-01

diffuse and occurring through SGD, small transient streams and/or coastal wetlands. Regarding transport quantifications, hydrogeochemical characteristics and pollution source loads may generally differ between larger, monitored catchments and smaller unmonitored coastal catchments. Since national hydrological monitoring data systematically exclude smaller, coastal catchments, they may not be representative for conditions in Forsmark (or Laxemar-Simpevarp). This emphasises the importance of extending in time the recently started hydrological and hydrogeochemical data series in the Forsmark and Laxemar-Simpevarp coastal catchment areas, since they are in effect unmonitored from a hydrological viewpoint, due to the lack of extended discharge time series. In the performed initial demonstration analysis of solute transport pathways from deep groundwater to recipients at the surface, we considered the main scenarios: (I) transport in the Quaternary deposits-bedrock interface zone only, and (II) transport in the coupled groundwater-surface water system. Considering mean travel times from each model cell to the coast, and disregarding travel times in the deep bedrock domain itself (which may be added to the here presented values), results show that travel times in scenario (II) were less than 4 years in 90% of the considered model area. Travel times were longer in scenario (I) with values higher than 10 years in 40% of the catchment area. These results are based on the assumption that the pathways do not go through zones of near-stagnant groundwater. If they would do so (and the above assumption is violated), results show that travel times can be considerably longer, for instance exceeding 400 years in half of the model area in scenario (I). Considering possible solute attenuation (caused by e.g. biogeochemical reactions or decay) along the hydrological transport pathways to inland surface waters and to the coast, we estimate solute mass delivery factors, representing the

Regional transport model of atmospheric sulfates

International Nuclear Information System (INIS)

Rao, K.S.; Thomson, I.; Egan, B.A.

1977-01-01

As part of the Sulfate Regional Experiment (SURE) Design Project, a regional transport model of atmospheric sulfates has been developed. This quasi-Lagrangian three-dimensional grid numerical model uses a detailed SO 2 emission inventory of major anthropogenic sources in the Eastern U.S. region, and observed meteorological data during an episode as inputs. The model accounts for advective transport and turbulent diffusion of the pollutants. The chemical transformation of SO 2 and SO 4 /sup =/ and the deposition of the species at the earth's surface are assumed to be linear processes at specified constant rates. The numerical model can predict the daily average concentrations of SO 2 and SO 4 /sup =/ at all receptor locations in the grid region during the episode. Because of the spatial resolution of the grid, this model is particularly suited to investigate the effect of tall stacks in reducing the ambient concentration levels of sulfur pollutants. This paper presents the formulations and assumptions of the regional sulfate transport model. The model inputs and results are discussed. Isopleths of predicted SO 2 and SO 4 /sup =/ concentrations are compared with the observed ground level values. The bulk of the information in this paper is directed to air pollution meteorologists and environmental engineers interested in the atmospheric transport modeling studies of sulfur oxide pollutants

Centrifuge modelling of contaminant transport processes

OpenAIRE

Culligan, P. J.; Savvidou, C.; Barry, D. A.

1996-01-01

Over the past decade, research workers have started to investigate problems of subsurface contaminant transport through physical modelling on a geotechnical centrifuge. A major advantage of this apparatus is its ability to model complex natural systems in a controlled laboratory environment In this paper, we discusses the principles and scaling laws related to the centrifugal modelling of contaminant transport, and presents four examples of recent work that has bee...

Development of the Transport Class Model (TCM) Aircraft Simulation From a Sub-Scale Generic Transport Model (GTM) Simulation

Science.gov (United States)

Hueschen, Richard M.

2011-01-01

A six degree-of-freedom, flat-earth dynamics, non-linear, and non-proprietary aircraft simulation was developed that is representative of a generic mid-sized twin-jet transport aircraft. The simulation was developed from a non-proprietary, publicly available, subscale twin-jet transport aircraft simulation using scaling relationships and a modified aerodynamic database. The simulation has an extended aerodynamics database with aero data outside the normal transport-operating envelope (large angle-of-attack and sideslip values). The simulation has representative transport aircraft surface actuator models with variable rate-limits and generally fixed position limits. The simulation contains a generic 40,000 lb sea level thrust engine model. The engine model is a first order dynamic model with a variable time constant that changes according to simulation conditions. The simulation provides a means for interfacing a flight control system to use the simulation sensor variables and to command the surface actuators and throttle position of the engine model.

Transperitoneal transport of creatinine. A comparison of kinetic models

DEFF Research Database (Denmark)

Fugleberg, S; Graff, J; Joffe, P

1994-01-01

Six kinetic models of transperitoneal creatinine transport were formulated and validated on the basis of experimental results obtained from 23 non-diabetic patients undergoing peritoneal dialysis. The models were designed to elucidate the presence or absence of diffusive, non-lymphatic convective...... including all three forms of transport is superior to other models. We conclude that the best model of transperitoneal creatinine transport includes diffusion, non-lymphatic convective transport and lymphatic convective transport....

Particle Tracking Model and Abstraction of Transport Processes

Energy Technology Data Exchange (ETDEWEB)

B. Robinson

2004-10-21

The purpose of this report is to document the abstraction model being used in total system performance assessment (TSPA) model calculations for radionuclide transport in the unsaturated zone (UZ). The UZ transport abstraction model uses the particle-tracking method that is incorporated into the finite element heat and mass model (FEHM) computer code (Zyvoloski et al. 1997 [DIRS 100615]) to simulate radionuclide transport in the UZ. This report outlines the assumptions, design, and testing of a model for calculating radionuclide transport in the UZ at Yucca Mountain. In addition, methods for determining and inputting transport parameters are outlined for use in the TSPA for license application (LA) analyses. Process-level transport model calculations are documented in another report for the UZ (BSC 2004 [DIRS 164500]). Three-dimensional, dual-permeability flow fields generated to characterize UZ flow (documented by BSC 2004 [DIRS 169861]; DTN: LB03023DSSCP9I.001 [DIRS 163044]) are converted to make them compatible with the FEHM code for use in this abstraction model. This report establishes the numerical method and demonstrates the use of the model that is intended to represent UZ transport in the TSPA-LA. Capability of the UZ barrier for retarding the transport is demonstrated in this report, and by the underlying process model (BSC 2004 [DIRS 164500]). The technical scope, content, and management of this report are described in the planning document ''Technical Work Plan for: Unsaturated Zone Transport Model Report Integration'' (BSC 2004 [DIRS 171282]). Deviations from the technical work plan (TWP) are noted within the text of this report, as appropriate. The latest version of this document is being prepared principally to correct parameter values found to be in error due to transcription errors, changes in source data that were not captured in the report, calculation errors, and errors in interpretation of source data.

Particle Tracking Model and Abstraction of Transport Processes

International Nuclear Information System (INIS)

Robinson, B.

2004-01-01

The purpose of this report is to document the abstraction model being used in total system performance assessment (TSPA) model calculations for radionuclide transport in the unsaturated zone (UZ). The UZ transport abstraction model uses the particle-tracking method that is incorporated into the finite element heat and mass model (FEHM) computer code (Zyvoloski et al. 1997 [DIRS 100615]) to simulate radionuclide transport in the UZ. This report outlines the assumptions, design, and testing of a model for calculating radionuclide transport in the UZ at Yucca Mountain. In addition, methods for determining and inputting transport parameters are outlined for use in the TSPA for license application (LA) analyses. Process-level transport model calculations are documented in another report for the UZ (BSC 2004 [DIRS 164500]). Three-dimensional, dual-permeability flow fields generated to characterize UZ flow (documented by BSC 2004 [DIRS 169861]; DTN: LB03023DSSCP9I.001 [DIRS 163044]) are converted to make them compatible with the FEHM code for use in this abstraction model. This report establishes the numerical method and demonstrates the use of the model that is intended to represent UZ transport in the TSPA-LA. Capability of the UZ barrier for retarding the transport is demonstrated in this report, and by the underlying process model (BSC 2004 [DIRS 164500]). The technical scope, content, and management of this report are described in the planning document ''Technical Work Plan for: Unsaturated Zone Transport Model Report Integration'' (BSC 2004 [DIRS 171282]). Deviations from the technical work plan (TWP) are noted within the text of this report, as appropriate. The latest version of this document is being prepared principally to correct parameter values found to be in error due to transcription errors, changes in source data that were not captured in the report, calculation errors, and errors in interpretation of source data

Change in cap rock porosity triggered by pressure and temperature dependent CO2–water–rock interactions in CO2 storage systems

Directory of Open Access Journals (Sweden)

Christina Hemme

2017-03-01

Full Text Available Carbon capture and storage in deep geological formations is a method to reduce greenhouse gas emissions. Supercritical CO2 is injected into a reservoir and dissolves in the brine. Under the impact of pressure and temperature (P–T the aqueous species of the CO2-acidified brine diffuse through the cap rock where they trigger CO2–water–rock interactions. These geochemical reactions result in mineral dissolution and precipitation along the CO2 migration path and are responsible for a change in porosity and therefore for the sealing capacity of the cap rock. This study focuses on the diffusive mass transport of CO2 along a gradient of decreasing P–T conditions. The process is retraced with a one-dimensional hydrogeochemical reactive mass transport model. The semi-generic hydrogeochemical model is based on chemical equilibrium thermodynamics. Based on a broad variety of scenarios, including different initial mineralogical, chemical and physical parameters, the hydrogeochemical parameters that are most sensitive for safe long-term CO2 storage are identified. The results demonstrate that P–T conditions have the strongest effect on the change in porosity and the effect of both is stronger at high P–T conditions because the solubility of the mineral phases involved depends on P–T conditions. Furthermore, modeling results indicate that the change in porosity depends strongly on the initial mineralogical composition of the reservoir and cap rock as well as on the brine compositions. Nevertheless, a wide range of conditions for safe CO2 storage is identified.

Ground-water solute transport modeling using a three-dimensional scaled model

International Nuclear Information System (INIS)

Crider, S.S.

1987-01-01

Scaled models are used extensively in current hydraulic research on sediment transport and solute dispersion in free surface flows (rivers, estuaries), but are neglected in current ground-water model research. Thus, an investigation was conducted to test the efficacy of a three-dimensional scaled model of solute transport in ground water. No previous results from such a model have been reported. Experiments performed on uniform scaled models indicated that some historical problems (e.g., construction and scaling difficulties; disproportionate capillary rise in model) were partly overcome by using simple model materials (sand, cement and water), by restricting model application to selective classes of problems, and by physically controlling the effect of the model capillary zone. Results from these tests were compared with mathematical models. Model scaling laws were derived for ground-water solute transport and used to build a three-dimensional scaled model of a ground-water tritium plume in a prototype aquifer on the Savannah River Plant near Aiken, South Carolina. Model results compared favorably with field data and with a numerical model. Scaled models are recommended as a useful additional tool for prediction of ground-water solute transport

Sediment transport modelling in a distributed physically based hydrological catchment model

Directory of Open Access Journals (Sweden)

M. Konz

2011-09-01

Full Text Available Bedload sediment transport and erosion processes in channels are important components of water induced natural hazards in alpine environments. A raster based distributed hydrological model, TOPKAPI, has been further developed to support continuous simulations of river bed erosion and deposition processes. The hydrological model simulates all relevant components of the water cycle and non-linear reservoir methods are applied for water fluxes in the soil, on the ground surface and in the channel. The sediment transport simulations are performed on a sub-grid level, which allows for a better discretization of the channel geometry, whereas water fluxes are calculated on the grid level in order to be CPU efficient. Several transport equations as well as the effects of an armour layer on the transport threshold discharge are considered. Flow resistance due to macro roughness is also considered. The advantage of this approach is the integrated simulation of the entire basin runoff response combined with hillslope-channel coupled erosion and transport simulation. The comparison with the modelling tool SETRAC demonstrates the reliability of the modelling concept. The devised technique is very fast and of comparable accuracy to the more specialised sediment transport model SETRAC.

Numerical Modelling Approaches for Sediment Transport in Sewer Systems

DEFF Research Database (Denmark)

Mark, Ole

A study of the sediment transport processes in sewers has been carried out. Based on this study a mathematical modelling system has been developed to describe the transport processes of sediments and dissolved matter in sewer systems. The modelling system consists of three sub-models which...... constitute the basic modelling system necessary to give a discription of the most dominant physical transport processes concerning particles and dissolved matter in sewer systems: A surface model. An advection-dispersion model. A sediment transport model....

Uranium hydrogeochemical and stream sediment reconnaissance of the Healy NTMS quadrangle, Alaska

International Nuclear Information System (INIS)

1981-05-01

Results of a hydrogeochemical and stream sediment reconnaissance of the Healy NTMS quadrangle, Alaska are presented. In addition to this abbreviated data release, more complete data are available to the public in machine-readable form. In this data release are location data, field analyses, and laboratory analyses of several different sample media. For the sake of brevity, many field site observations have not been included in this volume. These data are, however, available on the magnetic tape. Appendices A to D describe the sample media and summarize the analytical results for each medium. The data were subsetted by one of the Los Alamos National Laboratory (LANL) sorting programs into groups of stream sediment, lake sediment, stream water, lake water, and ground water samples. For each group which contains a sufficient number of observations, statistical tables, tables of raw data, and 1:1000000 scale maps of pertinent elements multivariate statistical analyses have been included

Uranium hydrogeochemical and stream sediment reconnaissance of the Seldovia NTMS quadrangle, Alaska

International Nuclear Information System (INIS)

1981-05-01

Results of a hydrogeochemical and stream sediment reconnaissance of the Seldovia NTMS quadrangle, Alaska are presented. In addition to this abbreviated data release, more complete data are available to the public in machine-readable form. In this data release are location data, field analyses, and laboratory analyses of several different sample media. For the sake of brevity, many field site observations have not been included in this volume. These data are, however, available on the magnetic tape. Appendices A to D describe the sample media and summarize the analytical results for each medium. The data were subsetted by one of the Los Alamos National Laboratory (LANL) sorting programs into groups of stream sediment, lake sediment, stream water, lake water, and ground water samples. For each group which contains a sufficient number of observations, statistical tables, tables of raw data, and 1:1000000 scale maps of pertinent elements have been included in this report

Transport simulations TFTR: Theoretically-based transport models and current scaling

International Nuclear Information System (INIS)

Redi, M.H.; Cummings, J.C.; Bush, C.E.; Fredrickson, E.; Grek, B.; Hahm, T.S.; Hill, K.W.; Johnson, D.W.; Mansfield, D.K.; Park, H.; Scott, S.D.; Stratton, B.C.; Synakowski, E.J.; Tang, W.M.; Taylor, G.

1991-12-01

In order to study the microscopic physics underlying observed L-mode current scaling, 1-1/2-d BALDUR has been used to simulate density and temperature profiles for high and low current, neutral beam heated discharges on TFTR with several semi-empirical, theoretically-based models previously compared for TFTR, including several versions of trapped electron drift wave driven transport. Experiments at TFTR, JET and D3-D show that I p scaling of τ E does not arise from edge modes as previously thought, and is most likely to arise from nonlocal processes or from the I p -dependence of local plasma core transport. Consistent with this, it is found that strong current scaling does not arise from any of several edge models of resistive ballooning. Simulations with the profile consistent drift wave model and with a new model for toroidal collisionless trapped electron mode core transport in a multimode formalism, lead to strong current scaling of τ E for the L-mode cases on TFTR. None of the theoretically-based models succeeded in simulating the measured temperature and density profiles for both high and low current experiments

Transportation Sector Model of the National Energy Modeling System. Volume 1

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-01-01

This report documents the objectives, analytical approach and development of the National Energy Modeling System (NEMS) Transportation Model (TRAN). The report catalogues and describes the model assumptions, computational methodology, parameter estimation techniques, model source code, and forecast results generated by the model. The NEMS Transportation Model comprises a series of semi-independent models which address different aspects of the transportation sector. The primary purpose of this model is to provide mid-term forecasts of transportation energy demand by fuel type including, but not limited to, motor gasoline, distillate, jet fuel, and alternative fuels (such as CNG) not commonly associated with transportation. The current NEMS forecast horizon extends to the year 2010 and uses 1990 as the base year. Forecasts are generated through the separate consideration of energy consumption within the various modes of transport, including: private and fleet light-duty vehicles; aircraft; marine, rail, and truck freight; and various modes with minor overall impacts, such as mass transit and recreational boating. This approach is useful in assessing the impacts of policy initiatives, legislative mandates which affect individual modes of travel, and technological developments. The model also provides forecasts of selected intermediate values which are generated in order to determine energy consumption. These elements include estimates of passenger travel demand by automobile, air, or mass transit; estimates of the efficiency with which that demand is met; projections of vehicle stocks and the penetration of new technologies; and estimates of the demand for freight transport which are linked to forecasts of industrial output. Following the estimation of energy demand, TRAN produces forecasts of vehicular emissions of the following pollutants by source: oxides of sulfur, oxides of nitrogen, total carbon, carbon dioxide, carbon monoxide, and volatile organic compounds.

Conceptual and Numerical Models for UZ Flow and Transport

International Nuclear Information System (INIS)

Liu, H.

2000-01-01

The purpose of this Analysis/Model Report (AMR) is to document the conceptual and numerical models used for modeling of unsaturated zone (UZ) fluid (water and air) flow and solute transport processes. This is in accordance with ''AMR Development Plan for U0030 Conceptual and Numerical Models for Unsaturated Zone (UZ) Flow and Transport Processes, Rev 00''. The conceptual and numerical modeling approaches described in this AMR are used for models of UZ flow and transport in fractured, unsaturated rock under ambient and thermal conditions, which are documented in separate AMRs. This AMR supports the UZ Flow and Transport Process Model Report (PMR), the Near Field Environment PMR, and the following models: Calibrated Properties Model; UZ Flow Models and Submodels; Mountain-Scale Coupled Processes Model; Thermal-Hydrologic-Chemical (THC) Seepage Model; Drift Scale Test (DST) THC Model; Seepage Model for Performance Assessment (PA); and UZ Radionuclide Transport Models

Particle Tracking Model and Abstraction of Transport Processes

International Nuclear Information System (INIS)

Robinson, B.

2000-01-01

The purpose of the transport methodology and component analysis is to provide the numerical methods for simulating radionuclide transport and model setup for transport in the unsaturated zone (UZ) site-scale model. The particle-tracking method of simulating radionuclide transport is incorporated into the FEHM computer code and the resulting changes in the FEHM code are to be submitted to the software configuration management system. This Analysis and Model Report (AMR) outlines the assumptions, design, and testing of a model for calculating radionuclide transport in the unsaturated zone at Yucca Mountain. In addition, methods for determining colloid-facilitated transport parameters are outlined for use in the Total System Performance Assessment (TSPA) analyses. Concurrently, process-level flow model calculations are being carrier out in a PMR for the unsaturated zone. The computer code TOUGH2 is being used to generate three-dimensional, dual-permeability flow fields, that are supplied to the Performance Assessment group for subsequent transport simulations. These flow fields are converted to input files compatible with the FEHM code, which for this application simulates radionuclide transport using the particle-tracking algorithm outlined in this AMR. Therefore, this AMR establishes the numerical method and demonstrates the use of the model, but the specific breakthrough curves presented do not necessarily represent the behavior of the Yucca Mountain unsaturated zone

SVM models for analysing the headstreams of mine water inrush

Energy Technology Data Exchange (ETDEWEB)

Yan Zhi-gang; Du Pei-jun; Guo Da-zhi [China University of Science and Technology, Xuzhou (China). School of Environmental Science and Spatial Informatics

2007-08-15

The support vector machine (SVM) model was introduced to analyse the headstrean of water inrush in a coal mine. The SVM model, based on a hydrogeochemical method, was constructed for recognising two kinds of headstreams and the H-SVMs model was constructed for recognising multi- headstreams. The SVM method was applied to analyse the conditions of two mixed headstreams and the value of the SVM decision function was investigated as a means of denoting the hydrogeochemical abnormality. The experimental results show that the SVM is based on a strict mathematical theory, has a simple structure and a good overall performance. Moreover the parameter W in the decision function can describe the weights of discrimination indices of the headstream of water inrush. The value of the decision function can denote hydrogeochemistry abnormality, which is significant in the prevention of water inrush in a coal mine. 9 refs., 1 fig., 7 tabs.

A Sediment Transport Model for Sewers

DEFF Research Database (Denmark)

Mark, Ole; Larsson, Johan; Larsen, Torben

1993-01-01

This paper describes a mathematical model for transport processes in sewers. The model consists of three sub models, a surface model for the description of the buildup and the washoff of sediment particles from the surface area, a morphological model and an advection-dispersion model. The model i...... is being developed as a part of a study being carried out at the University of Aalborg, Denmark and VBB VIAK, Sweden. The project is funded by the Swedish Water and Waste Water Works Association and the Nordic Industrial Foundation.......This paper describes a mathematical model for transport processes in sewers. The model consists of three sub models, a surface model for the description of the buildup and the washoff of sediment particles from the surface area, a morphological model and an advection-dispersion model. The model...

Modeling electrokinetic transport in phenol contaminated soils

Energy Technology Data Exchange (ETDEWEB)

Zorn, R.; Haus, R.; Czurda, K. [Dept. of Applied Geology, Univ. Karlsruhe (Germany)

2001-07-01

Numerical simulations are compared to laboratory experiments of electroremediation in soils contaminated by phenolic pollutants. The developing pH affects the electrokinetic transport behaviour of phenol. It is found that a water chemistry model must be included in an electrokinetic mass transport model to describe the process of electroremediation more accurately, if no buffering system is used at the electrodes. In the case of controlling the pH at the electrode compartments only a simplified chemical reaction model must be included in the numerical code to match the experimental phenolic transport. (orig.)

Abstracts of the symposium on unsaturated flow and transport modeling

International Nuclear Information System (INIS)

1982-03-01

Abstract titles are: Recent developments in modeling variably saturated flow and transport; Unsaturated flow modeling as applied to field problems; Coupled heat and moisture transport in unsaturated soils; Influence of climatic parameters on movement of radionuclides in a multilayered saturated-unsaturated media; Modeling water and solute transport in soil containing roots; Simulation of consolidation in partially saturated soil materials; modeling of water and solute transport in unsaturated heterogeneous fields; Fluid dynamics and mass transfer in variably-saturated porous media; Solute transport through soils; One-dimensional analytical transport modeling; Convective transport of ideal tracers in unsaturated soils; Chemical transport in macropore-mesopore media under partially saturated conditions; Influence of the tension-saturated zone on contaminant migration in shallow water regimes; Influence of the spatial distribution of velocities in porous media on the form of solute transport; Stochastic vs deterministic models for solute movement in the field; and Stochastic analysis of flow and solute transport

Modeling the fate transport of cesium in crushed granite

International Nuclear Information System (INIS)

Lee, C.B.; Kuo, Y.M.; Hsu, C.N.; Li, M.H.; Cheng, H.P.; Teng, S.P.

2005-01-01

Full text of publication follows: In order to assess the safety of a underground radwaste repository, reactive transport models suitable for evaluating the fate and transport of radionuclides need to be established based on experimental observation and analysis. The goal of this study is to construct adequate models simulating the reactive transport of cesium (Cs) in crushed granite through a systematic analysis, where synthetic groundwater (SGW) and synthetic seawater (SSW) were employed as the liquid phase. To build such models, this study applied N 2 -BET, x-ray diffraction (XRD), polar-microscopy/ auto-radiography, and solid-phase digestion for the analysis of granite, kinetic batch tests for the characterization of sorption/desorption of Cs, and multi-stage advection-dispersion column tests for the determination of major transport processes and the calibration/validation of hypothesized reactive transport models. Based on the results of solid phase analysis and batch tests, a two-site Langmuir kinetic model has been determined capable of appropriately describing Cs sorption/desorption under test conditions. From the results of non-reactive HTO column tests, a mobile/immobile transport model was proposed to capture the major transport processes in our column system. However, the combination of the two-site Langmuir model and the mobile/immobile transport model failed to provide numerical breakthrough curves matching the Cs experimental breakthroughs. It implied that our model needs to be further refined. To achieve this, the setup of our column test needs to be modified first to reduce the volume of column connecting space, so that the effect of extra diffusion/dispersion on breakthroughs would be minimized and major transport characteristics can be clearly revealed. Moreover, more investigations on the reaction mechanisms and transport processes of the reactive transport system must be conducted. (authors)

ATTILA - Atmospheric Tracer Transport In a Langrangian Model

Energy Technology Data Exchange (ETDEWEB)

Reithmeier, C.; Sausen, R.

2000-07-01

The Lagrangian model ATTILA (atmospheric tracer transport in a Lagrangian model) has been developed to treat the global-scale transport of passive trace species in the atmosphere within the framework of a general circulation model (GCM). ATTILA runs online within the GCM ECHAM4 and uses the GCM produced wind field to advect the centrois of 80.000 to 180.000 constant mass air parcels into which the model atmosphere is divided. Each trace constituent is thereby represented by a mass mixing ratio in each parcel. ATTILA contains state-of-the-art parameterizations of convection, turbulent boundary layer mixing, and interparcel transport and provides an algorithm to map the tracer concentrations from the trajectories to the ECHAM model grid. We use two experiments to evaluate the transport characteristics of ATTILA against observations and the standard semiLagrangian transport scheme of ECHAM. In the first experiment we simulate the distribution of the short-lived tracer Radon ({sup 222}Rn) in order to examine fast vertical transport over continents, and long-range transport from the continents to remote areas. In the second experiment, we simulate the distribution of radiocarbon ({sup 14}C) that was injected into the northern stratosphere during the nuclear weapon tests in the early 60ties, in order to examine upper tropospheric and stratospheric transport characteristics. ATTILA compares well to the observations and in many respects to the semiLagrangian scheme. However, contrary to the semiLagrangian scheme, ATTILA shows a greatly reduced meridional transport in the upper troposphere and lower stratosphere, and a reduced downward flux from the stratosphere to the troposphere, especially in midlatitudes. Since both transport schemes use the same model meteorology, we conclude that the often cited enhanced meridional transport and overestimated downward flux in ECHAM as described above is rather due to the numerical properties of the semiLagrangian scheme than due to an

Limitations of sorption isotherms on modeling groundwater contaminant transport

International Nuclear Information System (INIS)

Silva, Eduardo Figueira da

2007-01-01

Design and safety assessment of radioactive waste repositories, as well as remediation of radionuclide contaminated groundwater require the development of models capable of accurately predicting trace element fate and transport. Adsorption of trace radionuclides onto soils and groundwater is an important mechanism controlling near- and far- field transport. Although surface complexation models (SCMs) can better describe the adsorption mechanisms of most radionuclides onto mineral surfaces by directly accounting for variability of system properties and mineral surface properties, isotherms are still used to model contaminant transport in groundwater, despite the much higher system dependence. The present work investigates differences between transport model results based on these two approaches for adsorption modeling. A finite element transport model is used for the isotherm model, whereas the computer program PHREEQC is used for the SCM approach. Both models are calibrated for a batch experiment, and one-dimensional transport is simulated using the calibrated parameters. At the lower injected concentrations there are large discrepancies between SCM and isotherm transport predictions, with the SCM presenting much longer tails on the breakthrough curves. Isotherms may also provide non-conservative results for time to breakthrough and for maximum concentration in a contamination plume. Isotherm models are shown not to be robust enough to predict transport behavior of some trace elements, thus discouraging their use. The results also illustrate the promise of the SCM modeling approach in safety assessment and environmental remediation applications, also suggesting that independent batch sorption measurements can be used, within the framework of the SCM, to produce a more versatile and realistic groundwater transport model for radionuclides which is capable of accounting more accurately for temporal and spatial variations in geochemical conditions. (author)

Hydrogen recycle modeling in transport codes

International Nuclear Information System (INIS)

Howe, H.C.

1979-01-01

The hydrogen recycling models now used in Tokamak transport codes are reviewed and the method by which realistic recycling models are being added is discussed. Present models use arbitrary recycle coefficients and therefore do not model the actual recycling processes at the wall. A model for the hydrogen concentration in the wall serves two purposes: (1) it allows a better understanding of the density behavior in present gas puff, pellet, and neutral beam heating experiments; and (2) it allows one to extrapolate to long pulse devices such as EBT, ISX-C and reactors where the walls are observed or expected to saturate. Several wall models are presently being studied for inclusion in transport codes

Logistics and Transport - a conceptual model

DEFF Research Database (Denmark)

Jespersen, Per Homann; Drewes, Lise

2004-01-01

This paper describes how the freight transport sector is influenced by logistical principles of production and distribution. It introduces new ways of understanding freight transport as an integrated part of the changing trends of mobility. By introducing a conceptual model for understanding...... the interaction between logistics and transport, it points at ways to over-come inherent methodological difficulties when studying this relation...

Modelling of activity transport in PHWR

International Nuclear Information System (INIS)

Veena, S.N.; Rangarajan, S.; Narasimhan, S.V.; Horvath, G.L.

2000-01-01

The modelling of mass and activity transport in PHWR is of importance in predicting the build up of radiation field in and around the Primary Heat Transport system which will consequently help in planning the Dilute Chemical Decontamination and man rem budgeting. Modeling also helps in understanding the different parameters controlling the transport behaviour. Some of the important parameters include coolant chemistry like pH, physical parameters like temperature, the nature of the corrosion film and hence the effect of passivation techniques. VVER code for activity transport uses six nodes for the primary system and is essentially devised for stainless steel system. In the present work though based on this model, major modifications have been incorporated to suit the PHWR conditions. In the code, the PHT system of PHWR is suitably divided into 14 nodes, 5 in-core and 9 out of core nodes based on material and heat transfer properties. This paper describes the mechanisms involved in the various processes like generation of corrosion products, their release as well as their transport into the primary coolant, the activation of inactive corrosion product nuclides and the build up of radiation field due to 60 Co around the PHT system. (author)

Transport lattice models of heat transport in skin with spatially heterogeneous, temperature-dependent perfusion

Directory of Open Access Journals (Sweden)

Martin Gregory T

2004-11-01

Full Text Available Abstract Background Investigation of bioheat transfer problems requires the evaluation of temporal and spatial distributions of temperature. This class of problems has been traditionally addressed using the Pennes bioheat equation. Transport of heat by conduction, and by temperature-dependent, spatially heterogeneous blood perfusion is modeled here using a transport lattice approach. Methods We represent heat transport processes by using a lattice that represents the Pennes bioheat equation in perfused tissues, and diffusion in nonperfused regions. The three layer skin model has a nonperfused viable epidermis, and deeper regions of dermis and subcutaneous tissue with perfusion that is constant or temperature-dependent. Two cases are considered: (1 surface contact heating and (2 spatially distributed heating. The model is relevant to the prediction of the transient and steady state temperature rise for different methods of power deposition within the skin. Accumulated thermal damage is estimated by using an Arrhenius type rate equation at locations where viable tissue temperature exceeds 42°C. Prediction of spatial temperature distributions is also illustrated with a two-dimensional model of skin created from a histological image. Results The transport lattice approach was validated by comparison with an analytical solution for a slab with homogeneous thermal properties and spatially distributed uniform sink held at constant temperatures at the ends. For typical transcutaneous blood gas sensing conditions the estimated damage is small, even with prolonged skin contact to a 45°C surface. Spatial heterogeneity in skin thermal properties leads to a non-uniform temperature distribution during a 10 GHz electromagnetic field exposure. A realistic two-dimensional model of the skin shows that tissue heterogeneity does not lead to a significant local temperature increase when heated by a hot wire tip. Conclusions The heat transport system model of the

An optimization model for transportation of hazardous materials

International Nuclear Information System (INIS)

Seyed-Hosseini, M.; Kheirkhah, A. S.

2005-01-01

In this paper, the optimal routing problem for transportation of hazardous materials is studied. Routing for the purpose of reducing the risk of transportation of hazardous materials has been studied and formulated by many researcher and several routing models have been presented up to now. These models can be classified into the categories: the models for routing a single movement and the models for routing multiple movements. In this paper, according to the current rules and regulations of road transportations of hazardous materials in Iran, a routing problem is designed. In this problem, the routs for several independent movements are simultaneously determined. To examine the model, the problem the transportations of two different dangerous materials in the road network of Mazandaran province in the north of Iran is formulated and solved by applying Integer programming model

Multi-compartment Aerosol Transport Model

Energy Technology Data Exchange (ETDEWEB)

Hubbard, Joshua Allen; Santarpia, Joshua; Brotherton, Christopher M.; Omana, Michael Alexis; Rivera, Danielle; Lucero, Gabriel Anthony

2017-06-01

A simple aerosol transport model was developed for a multi-compartmented cleanroom. Each compartment was treated as a well-mixed volume with ventilating supply and return air. Gravitational settling, intercompartment transport, and leakage of exterior air into the system were included in the model. A set of first order, coupled, ordinary differential equations was derived from the conservation equations of aerosol mass and air mass. The system of ODEs was then solved in MATLAB using pre-existing numerical methods. The model was verified against cases of (1) constant inlet-duct concentration, and (2) exponentially decaying inlet-duct concentration. Numerical methods resulted in normalized error of less than 10 -9 when model solutions were compared to analytical solutions. The model was validated against experimental measurements from a single field test and showed good agreement in the shape and magnitude of the aerosol concentration profile with time.

Probabilistic finite-size transport models for fusion: Anomalous transport and scaling laws

International Nuclear Information System (INIS)

Milligen, B.Ph. van; Sanchez, R.; Carreras, B.A.

2004-01-01

Transport in fusion plasmas in the low confinement mode is characterized by several remarkable properties: the anomalous scaling of transport with system size, stiff (or 'canonical') profiles, power degradation, and rapid transport phenomena. The present article explores the possibilities of constructing a unified transport model, based on the continuous-time random walk, in which all these phenomena are handled adequately. The resulting formalism appears to be sufficiently general to provide a sound starting point for the development of a full-blown plasma transport code, capable of incorporating the relevant microscopic transport mechanisms, and allowing predictions of confinement properties

How Sensitive Are Transdermal Transport Predictions by Microscopic Stratum Corneum Models to Geometric and Transport Parameter Input?

Science.gov (United States)

Wen, Jessica; Koo, Soh Myoung; Lape, Nancy

2018-02-01

While predictive models of transdermal transport have the potential to reduce human and animal testing, microscopic stratum corneum (SC) model output is highly dependent on idealized SC geometry, transport pathway (transcellular vs. intercellular), and penetrant transport parameters (e.g., compound diffusivity in lipids). Most microscopic models are limited to a simple rectangular brick-and-mortar SC geometry and do not account for variability across delivery sites, hydration levels, and populations. In addition, these models rely on transport parameters obtained from pure theory, parameter fitting to match in vivo experiments, and time-intensive diffusion experiments for each compound. In this work, we develop a microscopic finite element model that allows us to probe model sensitivity to variations in geometry, transport pathway, and hydration level. Given the dearth of experimentally-validated transport data and the wide range in theoretically-predicted transport parameters, we examine the model's response to a variety of transport parameters reported in the literature. Results show that model predictions are strongly dependent on all aforementioned variations, resulting in order-of-magnitude differences in lag times and permeabilities for distinct structure, hydration, and parameter combinations. This work demonstrates that universally predictive models cannot fully succeed without employing experimentally verified transport parameters and individualized SC structures. Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

A mobile-mobile transport model for simulating reactive transport in connected heterogeneous fields

Science.gov (United States)

Lu, Chunhui; Wang, Zhiyuan; Zhao, Yue; Rathore, Saubhagya Singh; Huo, Jinge; Tang, Yuening; Liu, Ming; Gong, Rulan; Cirpka, Olaf A.; Luo, Jian

2018-05-01

Mobile-immobile transport models can be effective in reproducing heavily tailed breakthrough curves of concentration. However, such models may not adequately describe transport along multiple flow paths with intermediate velocity contrasts in connected fields. We propose using the mobile-mobile model for simulating subsurface flow and associated mixing-controlled reactive transport in connected fields. This model includes two local concentrations, one in the fast- and the other in the slow-flow domain, which predict both the concentration mean and variance. The normalized total concentration variance within the flux is found to be a non-monotonic function of the discharge ratio with a maximum concentration variance at intermediate values of the discharge ratio. We test the mobile-mobile model for mixing-controlled reactive transport with an instantaneous, irreversible bimolecular reaction in structured and connected random heterogeneous domains, and compare the performance of the mobile-mobile to the mobile-immobile model. The results indicate that the mobile-mobile model generally predicts the concentration breakthrough curves (BTCs) of the reactive compound better. Particularly, for cases of an elliptical inclusion with intermediate hydraulic-conductivity contrasts, where the travel-time distribution shows bimodal behavior, the prediction of both the BTCs and maximum product concentration is significantly improved. Our results exemplify that the conceptual model of two mobile domains with diffusive mass transfer in between is in general good for predicting mixing-controlled reactive transport, and particularly so in cases where the transfer in the low-conductivity zones is by slow advection rather than diffusion.

Hydrogeochemical Impact of CO₂ Leakage from Geological Sequestration on Shallow Potable Aquifers

DEFF Research Database (Denmark)

Cahill, Aaron Graham

. Although considered highly unlikely following appropriate site selection, leakage of CO2 from CCGS forms a major concern for both scientists and the public. Leakage would potentially occur through faults or abandoned boreholes and ultimately result in upward migration and discharge to the atmosphere....... During migration CO2 would dissolve into groundwater forming carbonic acid, induce water-rock reactions and thus change groundwater chemistry. Therefore prior to implementation of this potentially necessary technology, environmental risks associated with leakage must be understood. Over the past 10 years...... it be detected geochemically? Some common hydrochemical development is apparent from the literature however many aspects of hydrogeological and hydrogeochemical impact of leakage into shallow aquifers used in water supply remain unclear. In this Ph.D. study an integrated approach was employed in order to answer...

Modelling of sediment transport at Muria peninsula coastal, Jepara

International Nuclear Information System (INIS)

Heni Susiati; Yarianto SBS; Wahyu Pandoe; Eko Kusratmoko; Aris Poniman

2010-01-01

Modelling of transport sediment modelling at Muria Peninsula have been done. In this study we had been used mathematical model that consist of hydrodynamics and sediment transport . Data input for modelling has been used tidal, monsoon wind, and river debit. Simulation result of sediment transport modelling showed that tides pattern and seasonal variations are the main causes of variations in the suspended sediment distribution in Muria Peninsula. (author)

Modeling and analysis of transport in the mammary glands

Science.gov (United States)

Quezada, Ana; Vafai, Kambiz

2014-08-01

The transport of three toxins moving from the blood stream into the ducts of the mammary glands is analyzed in this work. The model predictions are compared with experimental data from the literature. The utility of the model lies in its potential to improve our understanding of toxin transport as a pre-disposing factor to breast cancer. This work is based on a multi-layer transport model to analyze the toxins present in the breast milk. The breast milk in comparison with other sampling strategies allows us to understand the mass transport of toxins once inside the bloodstream of breastfeeding women. The multi-layer model presented describes the transport of caffeine, DDT and cimetidine. The analysis performed takes into account the unique transport mechanisms for each of the toxins. Our model predicts the movement of toxins and/or drugs within the mammary glands as well as their bioaccumulation in the tissues.

Uranium hydrogeochemical and stream sediment reconnaissance of the Mt. Hayes NTMS quadrangle, Alaska

International Nuclear Information System (INIS)

1981-05-01

Results of a hydrogeochemical and stream sediment reconnaissance of the Mt. Hayes quadrangle, Alaska, are presented. In addition to this abbreviated data release, more complete data are available to the public in machine-readable form. In this data release are location data, field analyses, and Laboratory analyses of several different sample media. For the sake of brevity, many field site observations have not been included in this volume. These data are, however, available on the magnetic tape. Appendices A to D describe the sample media and summarize the analytical results for each medium. The data were subsetted by one of the Los Alamos National Laboratory (LANL) sorting programs into groups of stream sediment, lake sediment, stream water, lake water, and ground water samples. For each group which contains a sufficient number of observations, statistical tables, tables of raw data, and 1:1000000 scale maps of pertinent elements have been included in this report

Composite Transport Model and Water and Solute Transport across Plant Roots: An Update.

Science.gov (United States)

Kim, Yangmin X; Ranathunge, Kosala; Lee, Seulbi; Lee, Yejin; Lee, Deogbae; Sung, Jwakyung

2018-01-01

The present review examines recent experimental findings in root transport phenomena in terms of the composite transport model (CTM). It has been a well-accepted conceptual model to explain the complex water and solute flows across the root that has been related to the composite anatomical structure. There are three parallel pathways involved in the transport of water and solutes in roots - apoplast, symplast, and transcellular paths. The role of aquaporins (AQPs), which facilitate water flows through the transcellular path, and root apoplast is examined in terms of the CTM. The contribution of the plasma membrane bound AQPs for the overall water transport in the whole plant level was varying depending on the plant species, age of roots with varying developmental stages of apoplastic barriers, and driving forces (hydrostatic vs. osmotic). Many studies have demonstrated that the apoplastic barriers, such as Casparian bands in the primary anticlinal walls and suberin lamellae in the secondary cell walls, in the endo- and exodermis are not perfect barriers and unable to completely block the transport of water and some solute transport into the stele. Recent research on water and solute transport of roots with and without exodermis triggered the importance of the extension of conventional CTM adding resistances that arrange in series (epidermis, exodermis, mid-cortex, endodermis, and pericycle). The extension of the model may answer current questions about the applicability of CTM for composite water and solute transport of roots that contain complex anatomical structures with heterogeneous cell layers.

Uncertainty associated with selected environmental transport models

International Nuclear Information System (INIS)

Little, C.A.; Miller, C.W.

1979-11-01

A description is given of the capabilities of several models to predict accurately either pollutant concentrations in environmental media or radiological dose to human organs. The models are discussed in three sections: aquatic or surface water transport models, atmospheric transport models, and terrestrial and aquatic food chain models. Using data published primarily by model users, model predictions are compared to observations. This procedure is infeasible for food chain models and, therefore, the uncertainty embodied in the models input parameters, rather than the model output, is estimated. Aquatic transport models are divided into one-dimensional, longitudinal-vertical, and longitudinal-horizontal models. Several conclusions were made about the ability of the Gaussian plume atmospheric dispersion model to predict accurately downwind air concentrations from releases under several sets of conditions. It is concluded that no validation study has been conducted to test the predictions of either aquatic or terrestrial food chain models. Using the aquatic pathway from water to fish to an adult for 137 Cs as an example, a 95% one-tailed confidence limit interval for the predicted exposure is calculated by examining the distributions of the input parameters. Such an interval is found to be 16 times the value of the median exposure. A similar one-tailed limit for the air-grass-cow-milk-thyroid for 131 I and infants was 5.6 times the median dose. Of the three model types discussed in this report,the aquatic transport models appear to do the best job of predicting observed concentrations. However, this conclusion is based on many fewer aquatic validation data than were availaable for atmospheric model validation

One-Dimensional Transport with Equilibrium Chemistry (OTEQ) - A Reactive Transport Model for Streams and Rivers

Science.gov (United States)

Runkel, Robert L.

2010-01-01

OTEQ is a mathematical simulation model used to characterize the fate and transport of waterborne solutes in streams and rivers. The model is formed by coupling a solute transport model with a chemical equilibrium submodel. The solute transport model is based on OTIS, a model that considers the physical processes of advection, dispersion, lateral inflow, and transient storage. The equilibrium submodel is based on MINTEQ, a model that considers the speciation and complexation of aqueous species, acid-base reactions, precipitation/dissolution, and sorption. Within OTEQ, reactions in the water column may result in the formation of solid phases (precipitates and sorbed species) that are subject to downstream transport and settling processes. Solid phases on the streambed may also interact with the water column through dissolution and sorption/desorption reactions. Consideration of both mobile (waterborne) and immobile (streambed) solid phases requires a unique set of governing differential equations and solution techniques that are developed herein. The partial differential equations describing physical transport and the algebraic equations describing chemical equilibria are coupled using the sequential iteration approach. The model's ability to simulate pH, precipitation/dissolution, and pH-dependent sorption provides a means of evaluating the complex interactions between instream chemistry and hydrologic transport at the field scale. This report details the development and application of OTEQ. Sections of the report describe model theory, input/output specifications, model applications, and installation instructions. OTEQ may be obtained over the Internet at http://water.usgs.gov/software/OTEQ.

Reactive Transport Modeling of the Yucca Mountain Site, Nevada

International Nuclear Information System (INIS)

G. Bodvarsson

2004-01-01

The Yucca Mountain site has a dry climate and deep water table, with the repository located in the middle of an unsaturated zone approximately 600 m thick. Radionuclide transport processes from the repository to the water table are sensitive to the unsaturated zone flow field, as well as to sorption, matrix diffusion, radioactive decay, and colloid transport mechanisms. The unsaturated zone flow and transport models are calibrated against both physical and chemical data, including pneumatic pressure, liquid saturation, water potential, temperature, chloride, and calcite. The transport model predictions are further compared with testing specific to unsaturated zone transport: at Alcove 1 in the Exploratory Studies Facility (ESF), at Alcove 8 and Niche 3 of the ESF, and at the Busted Butte site. The models are applied to predict the breakthroughs at the water table for nonsorbing and sorbing radionuclides, with faults shown as the important paths for radionuclide transport. Daughter products of some important radionuclides, such as 239 Pu and 241 Am, have faster transport than the parents and must be considered in the unsaturated zone transport model. Colloid transport is significantly affected by colloid size, but only negligibly affected by lunetic declogging (reverse filtering) mechanisms. Unsaturated zone model uncertainties are discussed, including the sensitivity of breakthrough to the active fracture model parameter, as an example of uncertainties related to detailed flow characteristics and fracture-matrix interaction. It is expected that additional benefits from the unsaturated zone barrier for transport can be achieved by full implementation of the shadow zone concept immediately below the radionuclide release points in the waste emplacement drifts

Modeling and analysis of transport in the mammary glands

International Nuclear Information System (INIS)

Quezada, Ana; Vafai, Kambiz

2014-01-01

The transport of three toxins moving from the blood stream into the ducts of the mammary glands is analyzed in this work. The model predictions are compared with experimental data from the literature. The utility of the model lies in its potential to improve our understanding of toxin transport as a pre-disposing factor to breast cancer. This work is based on a multi-layer transport model to analyze the toxins present in the breast milk. The breast milk in comparison with other sampling strategies allows us to understand the mass transport of toxins once inside the bloodstream of breastfeeding women. The multi-layer model presented describes the transport of caffeine, DDT and cimetidine. The analysis performed takes into account the unique transport mechanisms for each of the toxins. Our model predicts the movement of toxins and/or drugs within the mammary glands as well as their bioaccumulation in the tissues. (paper)

Modeling Fate and Transport of Rotavirus in Surface Flow by Integrating WEPP and a Pathogen Transport Model

Science.gov (United States)

Bhattarai, R.; Kalita, P. K.; Davidson, P. C.; Kuhlenschmidt, M. S.

2012-12-01

More than 3.5 million people die each year from a water related diseases in this world. Every 20 seconds, a child dies from a water-related illness. Even in a developed country like the United States, there have been at least 1870 outbreaks associated with drinking water during the period of 1920 to 2002, causing 883,806 illnesses. Most of these outbreaks are resulted due to the presence of microbial pathogens in drinking water. Rotavirus infection has been recognized as the most common cause of diarrhea in young children throughout the world. Laboratory experiments conducted at the University of Illinois have demonstrated that recovery of rotavirus has been significantly affected by climatic and soil-surface conditions like slope, soil types, and ground cover. The objective of this study is to simulate the fate and transport of Rotavirus in overland and near-surface flow using a process-based model. In order to capture the dynamics of sediment-bound pathogens, the Water Erosion Prediction Project (WEPP) is coupled with the pathogen transport model. Transport of pathogens in overland flow can be simulated mathematically by including terms for the concentration of the pathogens in the liquid phase (in suspension or free-floating) and the solid phase (adsorbed to the fine solid particles like clay and silt). Advection, adsorption, and decay processes are considered. The mass balance equations are solved using numerical technique to predict spatial and temporal changes in pathogen concentrations in two phases. Outputs from WEPP simulations (flow velocity, depth, saturated conductivity and the soil particle fraction exiting in flow) are transferred as input for the pathogen transport model. Three soil types and three different surface cover conditions have been used in the experimental investigations. Results from these conditions have been used in calibrating and validating the simulation results. Bare surface conditions have produced very good agreement between

Integration of computational modeling with membrane transport studies reveals new insights into amino acid exchange transport mechanisms

Science.gov (United States)

Widdows, Kate L.; Panitchob, Nuttanont; Crocker, Ian P.; Please, Colin P.; Hanson, Mark A.; Sibley, Colin P.; Johnstone, Edward D.; Sengers, Bram G.; Lewis, Rohan M.; Glazier, Jocelyn D.

2015-01-01

Uptake of system L amino acid substrates into isolated placental plasma membrane vesicles in the absence of opposing side amino acid (zero-trans uptake) is incompatible with the concept of obligatory exchange, where influx of amino acid is coupled to efflux. We therefore hypothesized that system L amino acid exchange transporters are not fully obligatory and/or that amino acids are initially present inside the vesicles. To address this, we combined computational modeling with vesicle transport assays and transporter localization studies to investigate the mechanisms mediating [14C]l-serine (a system L substrate) transport into human placental microvillous plasma membrane (MVM) vesicles. The carrier model provided a quantitative framework to test the 2 hypotheses that l-serine transport occurs by either obligate exchange or nonobligate exchange coupled with facilitated transport (mixed transport model). The computational model could only account for experimental [14C]l-serine uptake data when the transporter was not exclusively in exchange mode, best described by the mixed transport model. MVM vesicle isolates contained endogenous amino acids allowing for potential contribution to zero-trans uptake. Both L-type amino acid transporter (LAT)1 and LAT2 subtypes of system L were distributed to MVM, with l-serine transport attributed to LAT2. These findings suggest that exchange transporters do not function exclusively as obligate exchangers.—Widdows, K. L., Panitchob, N., Crocker, I. P., Please, C. P., Hanson, M. A., Sibley, C. P., Johnstone, E. D., Sengers, B. G., Lewis, R. M., Glazier, J. D. Integration of computational modeling with membrane transport studies reveals new insights into amino acid exchange transport mechanisms. PMID:25761365

The Importance of Protons in Reactive Transport Modeling

Science.gov (United States)

McNeece, C. J.; Hesse, M. A.

2014-12-01

The importance of pH in aqueous chemistry is evident; yet, its role in reactive transport is complex. Consider a column flow experiment through silica glass beads. Take the column to be saturated and flowing with solution of a distinct pH. An instantaneous change in the influent solution pH can yield a breakthrough curve with both a rarefaction and shock component (composite wave). This behavior is unique among aqueous ions in transport and is more complex than intuition would tell. Analysis of the hyperbolic limit of this physical system can explain these first order transport phenomenon. This analysis shows that transport behavior is heavily dependent on the shape of the adsorption isotherm. Hence it is clear that accurate surface chemistry models are important in reactive transport. The proton adsorption isotherm has nonconstant concavity due to the proton's ability to partition into hydroxide. An eigenvalue analysis shows that an inflection point in the adsorption isotherm allows the development of composite waves. We use electrostatic surface complexation models to calculate realistic proton adsorption isotherms. Surface characteristics such as specific surface area, and surface site density were determined experimentally. We validate the model by comparison against silica glass bead flow through experiments. When coupled to surface complexation models, the transport equation captures the timing and behavior of breakthrough curves markedly better than with commonly used Langmuir assumptions. Furthermore, we use the adsorption isotherm to predict, a priori, the transport behavior of protons across pH composition space. Expansion of the model to multicomponent systems shows that proton adsorption can force composite waves to develop in the breakthrough curves of ions that would not otherwise exhibit such behavior. Given the abundance of reactive surfaces in nature and the nonlinearity of chemical systems, we conclude that building a greater understanding of

The Potential for Criticality Following Disposal of Uranium at Low-Level-Waste Facilities. Containerized Disposal

International Nuclear Information System (INIS)

Colten-Bradley, V.A.; Hopper, C.M.; Parks, C.V.; Toran, L.E.

1999-01-01

The purpose of this study was to evaluate whether or not fissile uranium in low-level-waste (LLW) facilities can be concentrated by hydrogeochemical processes to permit nuclear criticality. A team of experts in hydrology, geology, geochemistry, soil chemistry, and criticality safety was formed to develop and test some reasonable scenarios for hydrogeochemical increases in concentration of special nuclear material (SNM) and to use these scenarios to aid in evaluating the potential for nuclear criticality. The team's approach was to perform simultaneous hydrogeochemical and nuclear criticality studies to (1) identify some possible scenarios for uranium migration and concentration increase at LLW disposal facilities, (2) model groundwater transport and subsequent concentration increase via precipitation of uranium, and (3) evaluate the potential for nuclear criticality resulting from potential increase in uranium concentration over disposal limits. The analysis of SNM was restricted to 235 U in the present scope of work. The work documented in this report indicates that the potential for a criticality safety concern to arise in an LLW facility is extremely remote, but not impossible. Theoretically, conditions that lead to a potential criticality safety concern might arise. However, study of the hydrogeochemical mechanisms, the associated time frames, and the factors required for an actual criticality event indicate that proper emplacement of the SNM at the site can eliminate practical concerns relative to the occurrence and possible consequences of a criticality event

Uranium hydrogeochemical and stream sediment reconnaissance of the Philip Smith Mountains NTMS quadrangle, Alaska

International Nuclear Information System (INIS)

1981-09-01

Results of a hydrogeochemical and stream sediment reconnaissance of the Philip Smith Mountains NTMS quadrangle, Alaska are presented. In addition to this abbreviated data release, more complete data are available to the public in machine-readable form. In this data release are location data, field analyses, and laboratory analyses of several different sample media. For the sake of brevity, many field site observations have not been included in this volume. These data are, however, available on the magnetic tape. Appendices A and B describe the sample media and summarize the analytical results for each medium. The data were subsetted by one of the Los Alamos National Laboratory (LANL) sorting programs into groups of stream sediment and lake sediment samples. For each group which contains a sufficient number of observations, statistical tables, tables of raw data, and 1:1000000 scale maps of pertinent elements have been included in this report

Uranium hydrogeochemical and stream sediment reconnaissance of the Philip Smith Mountains NTMS quadrangle, Alaska

Energy Technology Data Exchange (ETDEWEB)

1981-09-01

Results of a hydrogeochemical and stream sediment reconnaissance of the Philip Smith Mountains NTMS quadrangle, Alaska are presented. In addition to this abbreviated data release, more complete data are available to the public in machine-readable form. In this data release are location data, field analyses, and laboratory analyses of several different sample media. For the sake of brevity, many field site observations have not been included in this volume. These data are, however, available on the magnetic tape. Appendices A and B describe the sample media and summarize the analytical results for each medium. The data were subsetted by one of the Los Alamos National Laboratory (LANL) sorting programs into groups of stream sediment and lake sediment samples. For each group which contains a sufficient number of observations, statistical tables, tables of raw data, and 1:1000000 scale maps of pertinent elements have been included in this report.

Impact of Transport Zone Number in Simulation Models on Cost-Benefit Analysis Results in Transport Investments

Science.gov (United States)

Chmielewski, Jacek

2017-10-01

Nowadays, feasibility studies need to be prepared for all planned transport investments, mainly those co-financed with UE grants. One of the fundamental aspect of feasibility study is the economic justification of an investment, evaluated in an area of so called cost-benefit analysis (CBA). The main goal of CBA calculation is to prove that a transport investment is really important for the society and should be implemented as economically efficient one. It can be said that the number of hours (PH - passengers hours) in trips and travelled kilometres (PK - passengers kilometres) are the most important for CBA results. The differences between PH and PK calculated for particular investment scenarios are the base for benefits calculation. Typically, transport simulation models are the best source for such data. Transport simulation models are one of the most powerful tools for transport network planning. They make it possible to evaluate forecast traffic volume and passenger flows in a public transport system for defined scenarios of transport and area development. There are many different transport models. Their construction is often similar, and they mainly differ in the level of their accuracy. Even models for the same area may differ in this matter. Typically, such differences come from the accuracy of supply side representation: road and public transport network representation. In many cases only main roads and a public transport network are represented, while local and service roads are eliminated as a way of reality simplification. This also enables a faster and more effective calculation process. On the other hand, the description of demand part of these models based on transport zones is often stable. Difficulties with data collection, mainly data on land use, resulted in the lack of changes in the analysed land division into so called transport zones. In this paper the author presents an influence of land division on the results of traffic analyses, and hence

Composite Transport Model and Water and Solute Transport across Plant Roots: An Update

Directory of Open Access Journals (Sweden)

Yangmin X. Kim

2018-02-01

Full Text Available The present review examines recent experimental findings in root transport phenomena in terms of the composite transport model (CTM. It has been a well-accepted conceptual model to explain the complex water and solute flows across the root that has been related to the composite anatomical structure. There are three parallel pathways involved in the transport of water and solutes in roots – apoplast, symplast, and transcellular paths. The role of aquaporins (AQPs, which facilitate water flows through the transcellular path, and root apoplast is examined in terms of the CTM. The contribution of the plasma membrane bound AQPs for the overall water transport in the whole plant level was varying depending on the plant species, age of roots with varying developmental stages of apoplastic barriers, and driving forces (hydrostatic vs. osmotic. Many studies have demonstrated that the apoplastic barriers, such as Casparian bands in the primary anticlinal walls and suberin lamellae in the secondary cell walls, in the endo- and exodermis are not perfect barriers and unable to completely block the transport of water and some solute transport into the stele. Recent research on water and solute transport of roots with and without exodermis triggered the importance of the extension of conventional CTM adding resistances that arrange in series (epidermis, exodermis, mid-cortex, endodermis, and pericycle. The extension of the model may answer current questions about the applicability of CTM for composite water and solute transport of roots that contain complex anatomical structures with heterogeneous cell layers.

Commercial Consolidation Model Applied to Transport Infrastructure

Energy Technology Data Exchange (ETDEWEB)

Guilherme de Aragão, J.J.; Santos Fontes Pereira, L. dos; Yamashita, Y.

2016-07-01

Since the 1990s, transport concessions, including public-private partnerships (PPPs), have been increasingly adopted by governments as an alternative for financing and operations in public investments, especially in transport infrastructure. The advantage pointed out by proponents of these models lies in merging the expertise and capital of the private sector to the public interest. Several arrangements are possible and have been employed in different cases. After the duration of the first PPP contracts in transportation, many authors have analyzed the success and failure factors of partnerships. The occurrence of failures in some stages of the process can greatly encumber the public administration, incurring losses to the fiscal responsibility of the competent bodies. This article aims to propose a new commercial consolidation model applied to transport infrastructure to ensure fiscal sustainability and overcome the weaknesses of current models. Initially, a systematic review of the literature covering studies on transport concessions between 1990 and 2015 is offered, where the different approaches between various countries are compared and the critical success factors indicated in the studies are identified. In the subsequent part of the paper, an approach for the commercial consolidation of the infrastructure concessions is presented, where the concessionary is paid following a finalistic performance model, which includes the overall fiscal balance of regional growth. Finally, the papers analyses the usefulness of the model in coping with the critical success factors explained before. (Author)

Modelling of Transport Projects Uncertainties

DEFF Research Database (Denmark)

Salling, Kim Bang; Leleur, Steen

2009-01-01

This paper proposes a new way of handling the uncertainties present in transport decision making based on infrastructure appraisals. The paper suggests to combine the principle of Optimism Bias, which depicts the historical tendency of overestimating transport related benefits and underestimating...... to supplement Optimism Bias and the associated Reference Class Forecasting (RCF) technique with a new technique that makes use of a scenario-grid. We tentatively introduce and refer to this as Reference Scenario Forecasting (RSF). The final RSF output from the CBA-DK model consists of a set of scenario......-based graphs which function as risk-related decision support for the appraised transport infrastructure project....

Fractional diffusion models of nonlocal transport

International Nuclear Information System (INIS)

Castillo-Negrete, D. del

2006-01-01

A class of nonlocal models based on the use of fractional derivatives (FDs) is proposed to describe nondiffusive transport in magnetically confined plasmas. FDs are integro-differential operators that incorporate in a unified framework asymmetric non-Fickian transport, non-Markovian ('memory') effects, and nondiffusive scaling. To overcome the limitations of fractional models in unbounded domains, we use regularized FDs that allow the incorporation of finite-size domain effects, boundary conditions, and variable diffusivities. We present an α-weighted explicit/implicit numerical integration scheme based on the Grunwald-Letnikov representation of the regularized fractional diffusion operator in flux conserving form. In sharp contrast with the standard diffusive model, the strong nonlocality of fractional diffusion leads to a linear in time response for a decaying pulse at short times. In addition, an anomalous fractional pinch is observed, accompanied by the development of an uphill transport region where the 'effective' diffusivity becomes negative. The fractional flux is in general asymmetric and, for steady states, it has a negative (toward the core) component that enhances confinement and a positive component that increases toward the edge and leads to poor confinement. The model exhibits the characteristic anomalous scaling of the confinement time, τ, with the system's size, L, τ∼L α , of low-confinement mode plasma where 1<α<2 is the order of the FD operator. Numerical solutions of the model with an off-axis source show that the fractional inward transport gives rise to profile peaking reminiscent of what is observed in tokamak discharges with auxiliary off-axis heating. Also, cold-pulse perturbations to steady sates in the model exhibit fast, nondiffusive propagation phenomena that resemble perturbative experiments

Numerical Modelling of Sediment Transport in Combined Sewer Systems

DEFF Research Database (Denmark)

Schlütter, Flemming

A conceptual sediment transport model has been developed. Through a case study a comparison with other numerical models is performed.......A conceptual sediment transport model has been developed. Through a case study a comparison with other numerical models is performed....

A model for development of freight transport; En model for godstransportens udvikling

Energy Technology Data Exchange (ETDEWEB)

Kveiborg, O. [National Environmental Res., Systems Analysis Dept. Roskilde (Denmark)

2001-01-01

This report describes the results of a large project conducted in a corporation between Statistics Denmark and the Danish National Environmental Research Institute. The main objective of the project has been to analyse the possibilities of prescribing the development in the Danish freight transport in a more appropriate and precise way than it is done by existing models. A secondary objective of the project was to develop a model based on the findings of the analysis. The intention was to be able to describe all areas of freight transport. The analysis has proven it impossible to improve the existing calculations in some areas of transport. Hence, the project has been narrowed down to focus exclusively on road freight transport. The developed model distinguishes itself from existing models by a much higher level of detail in the calculations. This enables the model to describe the structural relations between transport and economic activity, which has previously been subsumed in the aggregate calculations of existing models. The work carried out in the process of developing a model for the freight transport has encountered many difficulties. The findings described in this report are merely one step towards a better understanding of the relation between economic development and transport. The descriptions on the following pages will describe some of the difficulties we have had in achieving an appropriate statistical description of the different linkages. Furthermore, the calculations carried out with the model point at other unsolved problems. There is an indication that the model tends to overestimate the developments in freight transport. In this respect, the very disaggregate calculations of the model can be seen as both an advantage and as a disadvantage because each extra calculation gives rise to further uncertainties in the overall result. Even though we have had great difficulties finding adequate descriptions of the development in the factors in the model

Concept Layout Model of Transportation Terminals

Directory of Open Access Journals (Sweden)

Li-ya Yao

2012-01-01

Full Text Available Transportation terminal is the key node in transport systems. Efficient terminals can improve operation of passenger transportation networks, adjust the layout of public transportation networks, provide a passenger guidance system, and regulate the development of commercial forms, as well as optimize the assembly and distribution of modern logistic modes, among others. This study aims to clarify the relationship between the function and the structure of transportation terminals and establish the function layout design. The mapping mechanism of demand, function, and structure was analyzed, and a quantitative relationship between function and structure was obtained from a design perspective. Passenger demand and terminal structure were decomposed into several demand units and structural elements following the principle of reverse engineering. The relationship maps between these two kinds of elements were then analyzed. Function-oriented concept layout model of transportation terminals was established using the previous method. Thus, a technique in planning and design of transportation structures was proposed. Meaningful results were obtained from the optimization of transportation terminal facilities, which guide the design of the functional layout of transportation terminals and improve the development of urban passenger transportation systems.

Fractional diffusion models of transport in magnetically confined plasmas

International Nuclear Information System (INIS)

Castillo-Negrete, D. del; Carreras, B. A.; Lynch, V. E.

2005-01-01

Experimental and theoretical evidence suggests that transport in magnetically confined fusion plasmas deviates from the standard diffusion paradigm. Some examples include the confinement time scaling in L-mode plasmas, rapid pulse propagation phenomena, and inward transport in off-axis fueling experiments. The limitations of the diffusion paradigm can be traced back to the restrictive assumptions in which it is based. In particular, Fick's law, one of the cornerstones of diffusive transport, assumes that the fluxes only depend on local quantities, i. e. the spatial gradient of the field (s). another key issue is the Markovian assumption that neglects memory effects. Also, at a microscopic level, standard diffusion assumes and underlying Gaussian, uncorrelated stochastic process (i. e. a Brownian random walk) with well defined characteristic spatio-temporal scales. Motivated by the need to develop models of non-diffusive transport, we discuss here a class of transport models base on the use of fractional derivative operators. The models incorporates in a unified way non-Fickian transport, non-Markovian processes or memory effects, and non-diffusive scaling. At a microscopic level, the models describe an underlying stochastic process without characteristic spatio-temporal scales that generalizes the Brownian random walk. As a concrete case study to motivate and test the model, we consider transport of tracers in three-dimensional, pressure-gradient-driven turbulence. We show that in this system transport is non-diffusive and cannot be described in the context of the standard diffusion parading. In particular, the probability density function (pdf) of the radial displacements of tracers is strongly non-Gaussian with algebraic decaying tails, and the moments of the tracer displacements exhibit super-diffusive scaling. there is quantitative agreement between the turbulence transport calculations and the proposed fractional diffusion model. In particular, the model

Modeling of capacitated transportation systems for integral scheduling

NARCIS (Netherlands)

Ebben, Mark; van der Heijden, Matthijs C.; Hurink, Johann L.; Schutten, Johannes M.J.

2003-01-01

Motivated by a planned automated cargo transportation network, we consider transportation problems in which the finite capacity of resources has to be taken into account. We present a flexible modeling methodology which allows to construct, evaluate, and improve feasible solutions. The modeling is

Modeling of capacitated transportation systems for integral scheduling

NARCIS (Netherlands)

Ebben, Mark; van der Heijden, Matthijs C.; Hurink, Johann L.; Schutten, Johannes M.J.

2003-01-01

Motivated by a planned automated cargo transportation network, we consider transportation problems in which the finite capacity of resources has to be taken nto account. We present a flexible modeling methodology which allows to construct, evaluate, and improve feasible solutions. The modeling is

Modeling of Sediment Transport and Self-Cleansing in Sea Outfalls

DEFF Research Database (Denmark)

Larsen, Torben; Ibro, I.

2011-01-01

The paper describes an on-going project on modeling of sediment transport in outfalls with special focus on the self-cleansing problem occurring due to the daily flow variations seen in outfalls. The two central elements of the project is the development of the numerical model and a matching...... physical model in the laboratory. The numerical model covers both sediment transport over bed accumulations as well as transport over clean bottom. The physical modeling emphasizes on measurement of the non-steady removal and transport of welldefined and limited accumulations along the pipe. The paper...

Methods for testing transport models

International Nuclear Information System (INIS)

Singer, C.; Cox, D.

1991-01-01

Substantial progress has been made over the past year on six aspects of the work supported by this grant. As a result, we have in hand for the first time a fairly complete set of transport models and improved statistical methods for testing them against large databases. We also have initial results of such tests. These results indicate that careful application of presently available transport theories can reasonably well produce a remarkably wide variety of tokamak data

Uranium hydrogeochemical and stream sediment reconnaissance data release for the Wyoming portions of the Driggs, Preston, and Ogden NTMS Quadrangles

International Nuclear Information System (INIS)

Broxton, D.E.; Nunes, H.P.

1978-04-01

This report describes work done in the Wyoming portions of the Driggs and Preston, Wyoming/Idaho, and the Ogden, Wyoming/Utah, National Topographic Map Series (NTMS) quadrangles (1 : 250,000 scale) by the Los Alamos Scientific Laboratory (LASL) as part of the nationwide Hydrogeochemical and Stream Sediment Reconnaissance (HSSR). The HSSR is designed to identify areas having higher than normal concentrations of uranium in ground waters, surface waters, and water-transported sediments. During the fall of 1976, 1108 water samples and 1956 sediment samples were taken from 1999 locations by a private contractor within the Wyoming portion of Driggs, Preston, and Ogden quadrangles. An additional 108 water samples and 128 sediment samples were collected in the Grand Teton National Park during the fall of 1977 by staff members from the LASL. All of the samples were collected and treated according to standard specifications described in Appendix A. Uranium concentrations were determined at the LASL using standard analytical methods and procedures, also described briefly in Appendix A. Appendixes B-I through B-III and C-I through C-III are listings of all field and analytical data for the water and sediment samples, respectively. Appendixes D-I and D-II provide keys to codes used in the data listings. Statistical data describing the mean, range, and standard deviations of uranium concentrations are summarized by quadrangle and sample source-type in Tables I through III

Transport modeling of sorbing tracers in artificial fractures

International Nuclear Information System (INIS)

Keum, Dong Kwon; Baik, Min Hoon; Park, Chung Kyun; Cho, Young Hwan; Hahn, Phil Soo.

1998-02-01

This study was performed as part of a fifty-man year attachment program between AECL (Atomic Energy Canada Limited) and KAERI. Three kinds of computer code, HDD, POMKAP and VAMKAP, were developed to predict transport of contaminants in fractured rock. MDDM was to calculate the mass transport of contaminants in a single fracture using a simple hydrodynamic dispersion diffusion model. POMKAP was to predict the mass transport of contaminants by a two-dimensional variable aperture model. In parallel with modeling, the validation of models was also performed through the analysis of the migration experimental data obtained in acrylic plastic and granite artificial fracture system at the Whiteshell laboratories, AECL, Canada. (author). 34 refs., 11 tabs., 76 figs

Transport modeling of sorbing tracers in artificial fractures

Energy Technology Data Exchange (ETDEWEB)

Keum, Dong Kwon; Baik, Min Hoon; Park, Chung Kyun; Cho, Young Hwan; Hahn, Phil Soo

1998-02-01

This study was performed as part of a fifty-man year attachment program between AECL (Atomic Energy Canada Limited) and KAERI. Three kinds of computer code, HDD, POMKAP and VAMKAP, were developed to predict transport of contaminants in fractured rock. MDDM was to calculate the mass transport of contaminants in a single fracture using a simple hydrodynamic dispersion diffusion model. POMKAP was to predict the mass transport of contaminants by a two-dimensional variable aperture model. In parallel with modeling, the validation of models was also performed through the analysis of the migration experimental data obtained in acrylic plastic and granite artificial fracture system at the Whiteshell laboratories, AECL, Canada. (author). 34 refs., 11 tabs., 76 figs.

Coupling between solute transport and chemical reactions models

International Nuclear Information System (INIS)

Samper, J.; Ajora, C.

1993-01-01

During subsurface transport, reactive solutes are subject to a variety of hydrodynamic and chemical processes. The major hydrodynamic processes include advection and convection, dispersion and diffusion. The key chemical processes are complexation including hydrolysis and acid-base reactions, dissolution-precipitation, reduction-oxidation, adsorption and ion exchange. The combined effects of all these processes on solute transport must satisfy the principle of conservation of mass. The statement of conservation of mass for N mobile species leads to N partial differential equations. Traditional solute transport models often incorporate the effects of hydrodynamic processes rigorously but oversimplify chemical interactions among aqueous species. Sophisticated chemical equilibrium models, on the other hand, incorporate a variety of chemical processes but generally assume no-flow systems. In the past decade, coupled models accounting for complex hydrological and chemical processes, with varying degrees of sophistication, have been developed. The existing models of reactive transport employ two basic sets of equations. The transport of solutes is described by a set of partial differential equations, and the chemical processes, under the assumption of equilibrium, are described by a set of nonlinear algebraic equations. An important consideration in any approach is the choice of primary dependent variables. Most existing models cannot account for the complete set of chemical processes, cannot be easily extended to include mixed chemical equilibria and kinetics, and cannot handle practical two and three dimensional problems. The difficulties arise mainly from improper selection of the primary variables in the transport equations. (Author) 38 refs

Los Alamos Scientific Laboratory approach to hydrogeochemical and stream sediment reconnaissance for uranium in the United States

International Nuclear Information System (INIS)

Bolivar, S.L.

1981-01-01

The Los Alamos Scientific Laboratory of the United States is conducting a geochemical survey for uranium in the Rocky Mountain states of New Mexico, Colorado, Wyoming, and Montana and in Alaska. This survey is part of a national hydrogeochemical and stream sediment reconnaissance in which four Department of Energy laboratories will study the uranium resources of the United States to provide data for the National Uranium Resource Evaluation program. The reconnaissance will identify areas having higher than background concentrations of uranium in ground waters, surface waters, and water-transported sediments. Water and sediment samples are collected at a nominal density of one sample location per 10 km 2 except for lake areas of Alaska where the density is one sample location per 23 km 2 . Water samples are analyzed for uranium by fluorometry which has a 0.02 parts per billion lower limit of detection. Concentrations of 12 additional elements in water are determined by plasma-source emission spectrography. All sediments are analyzed for uranium by delayed-neutron counting with a 20 parts per billion lower limit of detection, which is well below the range of uranium concentrations in natural sediment samples. Elemental concentrations in sediments are also determined by neutron activation analysis for 31 elements by x-ray fluorescence for 9 elements, and by arc-source emission spectrography for 2 elements. The multielement analyses provide valuable data for studies concerning pathfinder elements, environmental pollution, elemental distributions, dispersion halos, and economic ore deposits other than uranium. To date, all of four Rocky Mountain states and about 80% of Alaska have been sampled. About 220,000 samples have been collected from an area of nearly 2,500,000 km 2

Coupling between a geochemical model and a transport model of dissolved elements

International Nuclear Information System (INIS)

Jacquier, P.

1988-10-01

In order to assess the safety analysis of an underground repository, the transport of radioelements in groundwater and their interactions with the geological medium are modelled. The objective of this work is the setting up and experimental validation of the coupling of a geochemical model with a transport model of dissolved elements. A laboratory experiment was developed at the CEA center of Cadarache. Flow-through experiments were carried out on columns filled with crushed limestone, where several inflow conditions were taken into account as the temperature, the presence of a pollutant (strontium chloride) at different concentrations. The results consist of the evolution of the chemical composition of the water at the outlet of the column. The final aim of the study is to explain these results with a coupled model where geochemical and transport phenomena are modelled in a two-step procedure. This code, called STELE, was built by introducing a geochemical code, CHIMERE, into an existing transport code, METIS. At this stage, the code CHIMERE can take into account: any chemical reaction in aqueous phase (complexation, acid-base reaction, redox equilibrium), dissolution-precipitation of minerals and solid phases, dissolution-degassing of gas. The paper intends to describe the whole process leading to the coupling which can be forecasted over the next years between geochemical and transport models

Hydrogeochemical Investigations of Historic Mining Districts, Central Western Slope of Colorado, Including Influence on Surface-Water Quality

Science.gov (United States)

Nash, J. Thomas

2002-01-01

This report describes reconnaissance hydrogeochemical investigations of 22 mining districts on the Western Slope of Colorado in the Gunnison and Uncompahgre National Forests and adjacent public lands administered by the Bureau of Land Management. Sources and fates of contaminants from historic mines, mine waste, and mill tailings are interpreted from chemical analyses for 190 samples of surface waters; 185 samples of mined rocks, mill tailings, and altered rocks; and passive leach analyses of 116 samples of those mineralized materials. Short reaches of several headwater streams show relatively low level effects of historic mining; the headwaters of the Uncompahgre River are highly contaminated by mines and unmined altered rocks in the Red Mountain district. There is encouraging evidence that natural processes attenuate mine-related contamination in most districts.

GEOS-5 Chemistry Transport Model User's Guide

Science.gov (United States)

Kouatchou, J.; Molod, A.; Nielsen, J. E.; Auer, B.; Putman, W.; Clune, T.

2015-01-01

The Goddard Earth Observing System version 5 (GEOS-5) General Circulation Model (GCM) makes use of the Earth System Modeling Framework (ESMF) to enable model configurations with many functions. One of the options of the GEOS-5 GCM is the GEOS-5 Chemistry Transport Model (GEOS-5 CTM), which is an offline simulation of chemistry and constituent transport driven by a specified meteorology and other model output fields. This document describes the basic components of the GEOS-5 CTM, and is a user's guide on to how to obtain and run simulations on the NCCS Discover platform. In addition, we provide information on how to change the model configuration input files to meet users' needs.

Sediment Transport Model for a Surface Irrigation System

Directory of Open Access Journals (Sweden)

Damodhara R. Mailapalli

2013-01-01

Full Text Available Controlling irrigation-induced soil erosion is one of the important issues of irrigation management and surface water impairment. Irrigation models are useful in managing the irrigation and the associated ill effects on agricultural environment. In this paper, a physically based surface irrigation model was developed to predict sediment transport in irrigated furrows by integrating an irrigation hydraulic model with a quasi-steady state sediment transport model to predict sediment load in furrow irrigation. The irrigation hydraulic model simulates flow in a furrow irrigation system using the analytically solved zero-inertial overland flow equations and 1D-Green-Ampt, 2D-Fok, and Kostiakov-Lewis infiltration equations. Performance of the sediment transport model was evaluated for bare and cropped furrow fields. The results indicated that the sediment transport model can predict the initial sediment rate adequately, but the simulated sediment rate was less accurate for the later part of the irrigation event. Sensitivity analysis of the parameters of the sediment module showed that the soil erodibility coefficient was the most influential parameter for determining sediment load in furrow irrigation. The developed modeling tool can be used as a water management tool for mitigating sediment loss from the surface irrigated fields.

A Lagrangian mixing frequency model for transported PDF modeling

Science.gov (United States)

Turkeri, Hasret; Zhao, Xinyu

2017-11-01

In this study, a Lagrangian mixing frequency model is proposed for molecular mixing models within the framework of transported probability density function (PDF) methods. The model is based on the dissipations of mixture fraction and progress variables obtained from Lagrangian particles in PDF methods. The new model is proposed as a remedy to the difficulty in choosing the optimal model constant parameters when using conventional mixing frequency models. The model is implemented in combination with the Interaction by exchange with the mean (IEM) mixing model. The performance of the new model is examined by performing simulations of Sandia Flame D and the turbulent premixed flame from the Cambridge stratified flame series. The simulations are performed using the pdfFOAM solver which is a LES/PDF solver developed entirely in OpenFOAM. A 16-species reduced mechanism is used to represent methane/air combustion, and in situ adaptive tabulation is employed to accelerate the finite-rate chemistry calculations. The results are compared with experimental measurements as well as with the results obtained using conventional mixing frequency models. Dynamic mixing frequencies are predicted using the new model without solving additional transport equations, and good agreement with experimental data is observed.

Understanding transport barriers through modelling

International Nuclear Information System (INIS)

Rozhansky, V

2004-01-01

Models of radial electric field formation are discussed and compared with the results of numerical simulations from fluid transport codes and Monte Carlo codes. A comparison of the fluid and Monte Carlo codes is presented. A conclusion is arrived at that all the simulations do not predict any bifurcation of the electric field, i.e. no bifurcation of poloidal rotation from low to high Mach number values is obtained. In most of the simulations, the radial electric field is close to the neoclassical electric field. The deviation from neoclassical electric field at the separatrix due to the existence of a transitional viscous layer is discussed. Scalings for the shear of the poloidal rotation are checked versus simulation results. It is demonstrated that assuming the critical shear to be of the order of 10 5 s -1 , it is possible to obtain a L-H transition power scaling close to that observed in the experiment. The dependence of the threshold on the magnetic field direction, pellet injection, aspect ratio and other factors are discussed on the basis of existing simulations. Transport codes where transport coefficients depend on the turbulence level and scenario simulations of L-H transition are analysed. However, the details of gyrofluid and gyrokinetic modelling should be discussed elsewhere. Simulations of internal transport barrier (ITB) formation are discussed as well as factors responsible for ITB formation

Global vertical mass transport by clouds - A two-dimensional model study

International Nuclear Information System (INIS)

Olofsson, Mats

1988-05-01

A two-dimensional global dispersion model, where vertical transport in the troposphere carried out by convective as well as by frontal cloud systems is explicitly treated, is developed from an existing diffusion model. A parameterization scheme for the cloud transport, based on global cloud statistics, is presented. The model has been tested by using Kr-85, Rn-222 and SO 2 as tracers. Comparisons have been made with observed distributions of these tracers, but also with model results without the cloud transport, using eddy diffusion as the primary means of vertical transport. The model results indicate that for trace species with a turnover time of days to weeks, the introduction of cloud-transport gives much more realistic simulations of their vertical distribution. Layers of increased mixing ratio with height, which can be found in real atmosphere, are reproduced in our cloud-transport model profiles, but can never be simulated with a pure eddy diffusion model. The horizontal transport in the model, by advection and eddy diffusion, gives a realistic distribution between the hemispheres of the more long-lived tracers (Kr-85). A combination of vertical transport by convective and frontal cloud systems is shown to improve the model simulations, compared to limiting it to convective transport only. The importance of including cumulus clouds in the convective transport scheme, in addition to the efficient transport by cumulonimbus clouds, is discussed. The model results are shown to be more sensitive to the vertical detrainment distribution profile than to the absolute magnitude of the vertical mass transport. The scavenging processes for SO 2 are parameterized without the introduction of detailed chemistry. An enhanced removal, due to the increased contact with droplets in the in-cloud lifting process, is introduced in the model. (author)

The role of mineral heterogeneity on the hydrogeochemical response of two fractured reservoir rocks in contact with dissolved CO2

Science.gov (United States)

Garcia Rios, Maria; Luquot, Linda; Soler, Josep M.; Cama, Jordi

2017-04-01

In this study we compare the hydrogeochemical response of two fractured reservoir rocks (limestone composed of 100 wt.% calcite and sandstone composed of 66 wt.% calcite, 28 wt.% quartz and 6 wt.% microcline) in contact with CO2-rich sulfate solutions. Flow-through percolation experiments were performed using artificially fractured limestone and sandstone cores and injecting a CO2-rich sulfate solution under a constant volumetric flow rate (from 0.2 to 60 mL/h) at P = 150 bar and T = 60 °C. Measurements of the pressure difference between the inlet and the outlet of the samples and of the aqueous chemistry enabled the determination of fracture permeability changes and net reaction rates. Additionally, X-ray computed microtomography (XCMT) was used to characterize and localized changes in fracture volume induced by dissolution and precipitation reactions. In all reacted cores an increase in fracture permeability and in fracture volume was always produced even when gypsum precipitation happened. The presence of inert silicate grains in sandstone samples favored the occurrence of largely distributed dissolution structures in contrast to localized dissolution in limestone samples. This phenomenon promoted greater dissolution and smaller precipitation in sandstone than in limestone experiments. As a result, in sandstone reservoirs, the larger increase in fracture volume as well as the more extended distribution of the created volume would favor the CO2 storage capacity. The different distribution of created volume between limestone and sandstone experiments led to a different variation in fracture permeability. The progressive stepped permeability increase for sandstone would be preferred to the sharp permeability increase for limestone to minimize risks related to CO2 injection, favor capillary trapping and reduce energetic storage costs. 2D reactive transport simulations that reproduce the variation in aqueous chemistry and the fracture geometry (dissolution pattern

Transport parameters for the modelling of water transport in ionomer membranes for PEM-fuel cells

International Nuclear Information System (INIS)

Meier, Frank; Eigenberger, Gerhart

2004-01-01

The water transport number (drag coefficient) and the hydraulic permeability were measured for Nafion. The results show a significant increase of both parameters with increasing water content indicating that they are strongly influenced by the membrane microstructure. Based on these experimental studies a new model approach to describe water transport in the H 2 -PEFC membrane is presented. This approach considers water transport by electro-osmosis caused by the proton flux through the membrane and by osmosis caused by a gradient in the chemical potential of water. It is parametrized by the measured data for the water transport number and the hydraulic permeability of Nafion. First simulation results applying this approach to a one-dimensional model of the H 2 -PEFC show good agreement with experimental data. Therefore, the developed model can be used for a new insight into the dominating mechanisms of water transport in the membrane

Mathematical modeling of solute transport in the subsurface

International Nuclear Information System (INIS)

Naymik, T.G.

1987-01-01

A review of key works on solute transport models indicates that solute transport processes with the exception of advection are still poorly understood. Solute transport models generally do a good job when they are used to test scientific concepts and hypotheses, investigate natural processes, systematically store and manage data, and simulate mass balance of solutes under certain natural conditions. Solute transport models generally are not good for predicting future conditions with a high degree of certainty, or for determining concentrations precisely. The mathematical treatment of solute transport far surpasses their understanding of the process. Investigations of the extent of groundwater contamination and methods to remedy existing problems show the along-term nature of the hazard. Industrial organic compounds may be immiscible in water, highly volatile, or complexed with inorganic as well as other organic compounds; many remain stable in nature almost indefinitely. In the worst case, future disposal of hazardous waste may be restricted to deep burial, as is proposed for radioactive wastes. For investigations pertinent to transport of radionuclides from a geologic repository, the process cannot be fully understood without adequate thermodynamic and kinetic data bases

Theoretical modeling of transport barriers in helical plasmas

International Nuclear Information System (INIS)

Toda, S.; Itoh, K.; Ohyabu, N.

2008-10-01

A unified transport modelling to explain electron Internal Transport Barriers (e-ITB) in helical plasmas and Internal Diffusion Barriers (IDB) observed in Large Helical Device (LHD) is proposed. The e-ITB can be predicted with the effect of zonal flows to obtain the e-ITB in the low collisional regime when the radial variation of the particle anomalous diffusivity is included. Transport analysis in this article can newly show that the particle fuelling induces the IDB formation when this unified transport modelling is used in the high collisional regime. The density limit for the IDB in helical plasmas is also examined including the effect of the radiation loss. (author)

Uranium transport around the reactor zone at Okelobondo (Oklo). Data evaluation with M3 and HYTEC

International Nuclear Information System (INIS)

Gurban, I.; Laaksoharju, M.; Made, B.; Ledoux, E.

1999-12-01

The Swedish Nuclear Fuel and Waste Management Company (SKB) is conducting and participating in Natural Analogue activities as part of various studies regarding the final disposal of high level nuclear waste (HLW). The aim of this study is to use the hydrogeological and hydrochemical data from Okelobondo (Oklo Natural Analogue) to compare the outcome of two independent modelling approaches (HYTEC and M3). The modelling helps to evaluate the processes associated with nuclear natural reactors such as redox, adsorption/desorption and dissolution/precipitation of the uranium and to develop more realistic codes which can be used for site investigations and data evaluation. HYTEC (1D and 2D) represents a deterministic, transport and multi-solutes reactive coupled code developed at Ecole des Mines de Paris. M3 (Multivariate Mixing and Mass balance calculations) is a mathematical-statistical concept code developed for SKB. M3 can relatively easily be used to calculate mixing portions and to identify sinks or sources of element concentrations that may exist in a geochemical system. M3 helped to address the reactions in the coupled code HYTEC. Thus, the major flow-paths and reaction paths were identified and used for transport evaluation. The reactive transport results (one-dimensional and two-dimensional simulations) are in good agreement with the statistical approach using the M3 model. M3 and HYTEC show a dissolution of the uranium layer in contact with upwardly oxidising waters. M3 and HYTEC show a gain of manganese rich minerals downstream the reactor. A comparison of the U and Mn plots for M3 deviation and HYTEC results showed an almost mirror behaviour. The U transport stops when the Mn gain increases. Thus, HYTEC and M3 modelling predict that a possible reason for not having U transport up to the surface in Okelobondo is due to an inorganic trap which may hinder the uranium transport. The two independent modelling approaches can be used to complement each other and to

Plasma transport simulation modeling for helical confinement systems

International Nuclear Information System (INIS)

Yamazaki, K.; Amano, T.

1991-08-01

New empirical and theoretical transport models for helical confinement systems are developed based on the neoclassical transport theory including the effect of radial electric field and multi-helicity magnetic components, and the drift wave turbulence transport for electrostatic and electromagnetic modes, or the anomalous semi-empirical transport. These electron thermal diffusivities are compared with CHS (Compact Helical System) experimental data, which indicates that the central transport coefficient of the ECH plasma agrees with the neoclassical axi-symmetric value and the transport outside the half radius is anomalous. On the other hand, the transport of NBI-heated plasmas is anomalous in the whole plasma region. This anomaly is not explained by the electrostatic drift wave turbulence models in these flat-density-profile discharges. For the detailed prediction of plasma parameters in LHD (Large Helical Device), 3-D(dimensional) equilibrium/1-D transport simulations including empirical or drift wave turbulence models are carried out, which suggests that the global confinement time of LHD is determined mainly by the electron anomalous transport near the plasma edge region rather than the helical ripple transport in the core region. Even if the ripple loss can be eliminated, the increase of the global confinement is 10%. However, the rise in the central ion temperature is more than 20%. If the anomalous loss can be reduced to the half level of the present scaling, like so-called 'H-mode' of the tokamak discharge, the neoclassical ripple loss through the ion channel becomes important even in the plasma core. The 5% radial inward shift of the plasma column with respect to the major radius is effective for improving plasma confinement and raising more than 50% of the fusion product by reducing this neoclassical asymmetric ion transport loss and increasing 10% in the plasma radius. (author)

Evaluation of cloud convection and tracer transport in a three-dimensional chemical transport model

Directory of Open Access Journals (Sweden)

W. Feng

2011-06-01

Full Text Available We investigate the performance of cloud convection and tracer transport in a global off-line 3-D chemical transport model. Various model simulations are performed using different meteorological (reanalyses (ERA-40, ECMWF operational and ECMWF Interim to diagnose the updraft mass flux, convective precipitation and cloud top height.

The diagnosed upward mass flux distribution from TOMCAT agrees quite well with the ECMWF reanalysis data (ERA-40 and ERA-Interim below 200 hPa. Inclusion of midlevel convection improves the agreement at mid-high latitudes. However, the reanalyses show strong convective transport up to 100 hPa, well into the tropical tropopause layer (TTL, which is not captured by TOMCAT. Similarly, the model captures the spatial and seasonal variation of convective cloud top height although the mean modelled value is about 2 km lower than observed.

The ERA-Interim reanalyses have smaller archived upward convective mass fluxes than ERA-40, and smaller convective precipitation, which is in better agreement with satellite-based data. TOMCAT captures these relative differences when diagnosing convection from the large-scale fields. The model also shows differences in diagnosed convection with the version of the operational analyses used, which cautions against using results of the model from one specific time period as a general evaluation.

We have tested the effect of resolution on the diagnosed modelled convection with simulations ranging from 5.6° × 5.6° to 1° × 1°. Overall, in the off-line model, the higher model resolution gives stronger vertical tracer transport, however, it does not make a large change to the diagnosed convective updraft mass flux (i.e., the model results using the convection scheme fail to capture the strong convection transport up to 100 hPa as seen in the archived convective mass fluxes. Similarly, the resolution of the forcing winds in the higher resolution CTM does not make a

Modelling Emission of Pollutants from transportation using mobile sensing data

DEFF Research Database (Denmark)

Lehmann, Anders

The advent and the proliferation of the smartphone has promised new possibilities for researchers to gain knowledge about the habits and behaviour of people, as the ubiqui- tous smartphone with an array of sensors is capable of deliver a wealth of information. This dissertation addresses methods...... to use data acquired from smartphones to im- prove transportation related air quality models and models for climate gas emission from transportation. These models can be used for planning of transportation net- works, monitoring of air quality, and automate transport related green accounting. More...... database imple- mentations are a subfield of computer science. I have worked to bring these diverse research fields together to solve the challenge of improving modelling of transporta- tion related air quality emissions as well as modelling of transportation related climate gas emissions. The main...

A mathematical model of inter-terminal transportation

DEFF Research Database (Denmark)

Tierney, Kevin; Voß, Stefan; Stahlbock, Robert

2014-01-01

contains special structures to model the long term loading and unloading of vehicles, and our model is general enough to model a number of important real-world aspects of ITT, such as traffic congestion, penalized late container delivery, multiple ITT transportation modes, and port infrastructure...... modifications. We show that our model can scale to real-world sizes and provide ports with important information for their long term decision making.......We present a novel integer programming model for analyzing inter-terminal transportation (ITT) in new and expanding sea ports. ITT is the movement of containers between terminals (sea, rail or otherwise) within a port. ITT represents a significant source of delay for containers being transshipped...

Modelling of Transport Projects Uncertainties

DEFF Research Database (Denmark)

Salling, Kim Bang; Leleur, Steen

2012-01-01

This paper proposes a new way of handling the uncertainties present in transport decision making based on infrastructure appraisals. The paper suggests to combine the principle of Optimism Bias, which depicts the historical tendency of overestimating transport related benefits and underestimating...... to supplement Optimism Bias and the associated Reference Class Forecasting (RCF) technique with a new technique that makes use of a scenario-grid. We tentatively introduce and refer to this as Reference Scenario Forecasting (RSF). The final RSF output from the CBA-DK model consists of a set of scenario......-based graphs which functions as risk-related decision support for the appraised transport infrastructure project. The presentation of RSF is demonstrated by using an appraisal case concerning a new airfield in the capital of Greenland, Nuuk....

Variational multiscale models for charge transport.

Science.gov (United States)

Wei, Guo-Wei; Zheng, Qiong; Chen, Zhan; Xia, Kelin

2012-01-01

This work presents a few variational multiscale models for charge transport in complex physical, chemical and biological systems and engineering devices, such as fuel cells, solar cells, battery cells, nanofluidics, transistors and ion channels. An essential ingredient of the present models, introduced in an earlier paper (Bulletin of Mathematical Biology, 72, 1562-1622, 2010), is the use of differential geometry theory of surfaces as a natural means to geometrically separate the macroscopic domain from the microscopic domain, meanwhile, dynamically couple discrete and continuum descriptions. Our main strategy is to construct the total energy functional of a charge transport system to encompass the polar and nonpolar free energies of solvation, and chemical potential related energy. By using the Euler-Lagrange variation, coupled Laplace-Beltrami and Poisson-Nernst-Planck (LB-PNP) equations are derived. The solution of the LB-PNP equations leads to the minimization of the total free energy, and explicit profiles of electrostatic potential and densities of charge species. To further reduce the computational complexity, the Boltzmann distribution obtained from the Poisson-Boltzmann (PB) equation is utilized to represent the densities of certain charge species so as to avoid the computationally expensive solution of some Nernst-Planck (NP) equations. Consequently, the coupled Laplace-Beltrami and Poisson-Boltzmann-Nernst-Planck (LB-PBNP) equations are proposed for charge transport in heterogeneous systems. A major emphasis of the present formulation is the consistency between equilibrium LB-PB theory and non-equilibrium LB-PNP theory at equilibrium. Another major emphasis is the capability of the reduced LB-PBNP model to fully recover the prediction of the LB-PNP model at non-equilibrium settings. To account for the fluid impact on the charge transport, we derive coupled Laplace-Beltrami, Poisson-Nernst-Planck and Navier-Stokes equations from the variational principle

Variational multiscale models for charge transport

Science.gov (United States)

Wei, Guo-Wei; Zheng, Qiong; Chen, Zhan; Xia, Kelin

2012-01-01

This work presents a few variational multiscale models for charge transport in complex physical, chemical and biological systems and engineering devices, such as fuel cells, solar cells, battery cells, nanofluidics, transistors and ion channels. An essential ingredient of the present models, introduced in an earlier paper (Bulletin of Mathematical Biology, 72, 1562-1622, 2010), is the use of differential geometry theory of surfaces as a natural means to geometrically separate the macroscopic domain from the microscopic domain, meanwhile, dynamically couple discrete and continuum descriptions. Our main strategy is to construct the total energy functional of a charge transport system to encompass the polar and nonpolar free energies of solvation, and chemical potential related energy. By using the Euler-Lagrange variation, coupled Laplace-Beltrami and Poisson-Nernst-Planck (LB-PNP) equations are derived. The solution of the LB-PNP equations leads to the minimization of the total free energy, and explicit profiles of electrostatic potential and densities of charge species. To further reduce the computational complexity, the Boltzmann distribution obtained from the Poisson-Boltzmann (PB) equation is utilized to represent the densities of certain charge species so as to avoid the computationally expensive solution of some Nernst-Planck (NP) equations. Consequently, the coupled Laplace-Beltrami and Poisson-Boltzmann-Nernst-Planck (LB-PBNP) equations are proposed for charge transport in heterogeneous systems. A major emphasis of the present formulation is the consistency between equilibrium LB-PB theory and non-equilibrium LB-PNP theory at equilibrium. Another major emphasis is the capability of the reduced LB-PBNP model to fully recover the prediction of the LB-PNP model at non-equilibrium settings. To account for the fluid impact on the charge transport, we derive coupled Laplace-Beltrami, Poisson-Nernst-Planck and Navier-Stokes equations from the variational principle

Modeling of pollutant emissions from road transport; Modelisation des emissions de polluants par le transport routier

Energy Technology Data Exchange (ETDEWEB)

NONE

2003-07-01

COPERT III (computer programme to calculate emissions from road transport) is the third version of an MS Windows software programme aiming at the calculation of air pollutant emissions from road transport. COPERT estimates emissions of all regulated air pollutants (CO, NO{sub x}, VOC, PM) produced by different vehicle categories as well as CO{sub 2} emissions on the basis of fuel consumption. This research seminar was organized by the French agency of environment and energy mastery (Ademe) around the following topics: the uncertainties and sensitiveness analysis of the COPERT III model, the presentation of case studies that use COPERT III for the estimation of road transport emissions, and the future of the modeling of road transport emissions: from COPERT III to ARTEMIS (assessment and reliability of transport emission models and inventory systems). This document is a compilation of 8 contributions to this seminar and dealing with: the uncertainty and sensitiveness analysis of the COPERT III model; the road mode emissions of the ESCOMPTE program: sensitivity study; the sensitivity analysis of the spatialized traffic at the time-aggregation level: application in the framework of the INTERREG project (Alsace); the road transport aspect of the regional air quality plan of Bourgogne region: exhaustive consideration of the road network; intercomparison of tools and methods for the inventory of emissions of road transport origin; evolution of the French park of vehicles by 2025: new projections; application of COPERT III to the French context: a new version of IMPACT-ADEME; the European ARTEMIS project: new structural considerations for the modeling of road transport emissions. (J.S.)

Using Transport Diagnostics to Understand Chemistry Climate Model Ozone Simulations

Science.gov (United States)

Strahan, S. E.; Douglass, A. R.; Stolarski, R. S.; Akiyoshi, H.; Bekki, S.; Braesicke, P.; Butchart, N.; Chipperfield, M. P.; Cugnet, D.; Dhomse, S.;

Modelling an Ammonium Transporter with SCLS

Directory of Open Access Journals (Sweden)

Angelo Troina

2009-10-01

Full Text Available The Stochastic Calculus of Looping Sequences (SCLS is a recently proposed modelling language for the representation and simulation of biological systems behaviour. It has been designed with the aim of combining the simplicity of notation of rewrite systems with the advantage of compositionality. It also allows a rather simple and accurate description of biological membranes and their interactions with the environment.In this work we apply SCLS to model a newly discovered ammonium transporter. This transporter is believed to play a fundamental role for plant mineral acquisition, which takes place in the arbuscular mycorrhiza, the most wide-spread plant-fungus symbiosis on earth. Due to its potential application in agriculture this kind of symbiosis is one of the main focuses of the BioBITs project. In our experiments the passage of NH3 / NH4+ from the fungus to the plant has been dissected in known and hypothetical mechanisms; with the model so far we have been able to simulate the behaviour of the system under different conditions. Our simulations confirmed some of the latest experimental results about the LjAMT2;2 transporter. The initial simulation results of the modelling of the symbiosis process are promising and indicate new directions for biological investigations.

Mathematical Model of Ion Transport in Electrodialysis Process

Directory of Open Access Journals (Sweden)

F.S. Rohman

2010-10-01

Full Text Available Mathematical models of ion transport in electrodialysis process is reviewed and their basics concept is discussed. Three scales of ion transport reviewed are: 1 ion transport in the membrane, where two approaches are used, the irreversible thermodynamics and modeling of the membrane material; 2 ion transport in a three-layer system composed of a membrane with two adjoining diffusion layers; and 3 coupling with hydraulic flow system in an electrodialysis 2D and 3D cell, where the differential equation of convectivediffusion is used. Most of the work carried out in the past implemented NP equations since relatively easily coupled with other equations describing hydrodynamic conditions and ion transport in the surrounding solutions, chemical reactions in the solutions and the membrane, boundary and other conditions. However, it is limited to point ionic transport in homogenous and uniformly - grainy phases of structure. © 2008 BCREC UNDIP. All rights reserved.[Received: 21 January 2008, Accepted: 10 March 2008][How to Cite: F.S. Rohman, N. Aziz (2008. Mathematical Model of Ion Transport in Electrodialysis Process. Bulletin of Chemical Reaction Engineering and Catalysis, 3(1-3: 3-8. doi:10.9767/bcrec.3.1-3.7122.3-8][How to Link/DOI: http://dx.doi.org/10.9767/bcrec.3.1-3.7122.3-8 || or local: http://ejournal.undip.ac.id/index.php/bcrec/article/view/7122 ] 

The potential for criticality following disposal of uranium at low-level waste facilities: Uranium blended with soil

Energy Technology Data Exchange (ETDEWEB)

Toran, L.E.; Hopper, C.M.; Naney, M.T. [and others

1997-06-01

The purpose of this study was to evaluate whether or not fissile uranium in low-level-waste (LLW) facilities can be concentrated by hydrogeochemical processes to permit nuclear criticality. A team of experts in hydrology, geology, geochemistry, soil chemistry, and criticality safety was formed to develop achievable scenarios for hydrogeochemical increases in concentration of special nuclear material (SNM), and to use these scenarios to aid in evaluating the potential for nuclear criticality. The team`s approach was to perform simultaneous hydrogeochemical and nuclear criticality studies to (1) identify some achievable scenarios for uranium migration and concentration increase at LLW disposal facilities, (2) model groundwater transport and subsequent concentration increase via sorption or precipitation of uranium, and (3) evaluate the potential for nuclear criticality resulting from potential increases in uranium concentration over disposal limits. The analysis of SNM was restricted to {sup 235}U in the present scope of work. The outcome of the work indicates that criticality is possible given established regulatory limits on SNM disposal. However, a review based on actual disposal records of an existing site operation indicates that the potential for criticality is not a concern under current burial practices.

The potential for criticality following disposal of uranium at low-level waste facilities: Uranium blended with soil

International Nuclear Information System (INIS)

Toran, L.E.; Hopper, C.M.; Naney, M.T.

1997-06-01

The purpose of this study was to evaluate whether or not fissile uranium in low-level-waste (LLW) facilities can be concentrated by hydrogeochemical processes to permit nuclear criticality. A team of experts in hydrology, geology, geochemistry, soil chemistry, and criticality safety was formed to develop achievable scenarios for hydrogeochemical increases in concentration of special nuclear material (SNM), and to use these scenarios to aid in evaluating the potential for nuclear criticality. The team's approach was to perform simultaneous hydrogeochemical and nuclear criticality studies to (1) identify some achievable scenarios for uranium migration and concentration increase at LLW disposal facilities, (2) model groundwater transport and subsequent concentration increase via sorption or precipitation of uranium, and (3) evaluate the potential for nuclear criticality resulting from potential increases in uranium concentration over disposal limits. The analysis of SNM was restricted to 235 U in the present scope of work. The outcome of the work indicates that criticality is possible given established regulatory limits on SNM disposal. However, a review based on actual disposal records of an existing site operation indicates that the potential for criticality is not a concern under current burial practices

Clinton River Sediment Transport Modeling Study

Science.gov (United States)

The U.S. ACE develops sediment transport models for tributaries to the Great Lakes that discharge to AOCs. The models developed help State and local agencies to evaluate better ways for soil conservation and non-point source pollution prevention.

Atmospheric transport of persistent organic pollutants - development of a 3-d dynamical transport model covering the northern hemisphere

Science.gov (United States)

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

2003-04-01

The Danish Eulerian Hemispheric Model (DEHM) is a 3-D dynamical atmospheric transport model originally developed to describe the atmospheric transport of sulphur, lead, and mercury to the Arctic. The model has been validated carefully for these compounds. A new version of DEHM is currently being developed to describe the atmospheric transport of persistent organic pollutants (POPs) which are toxic, lipophilic and bio-accumulating compounds showing great persistence in the environment. The model has a horizontal resolution of 150 km x 150 km and 18 vertical layers, and it is driven by meteorological data from the numerical weather prediction model MM5V2. During environmental cycling POPs can be deposited and re-emitted several times before reaching a final destination. A description of the exchange processes between the land/ocean surfaces and the atmosphere is included in the model to account for this multi-hop transport. The present model version describes the atmospheric transport of the pesticide alpha-hexachlorocyclohexane (alpha-HCH). Other POPs may be included when proper data on emissions and physical-chemical parameters becomes available. The model-processes and the first model results are presented. The atmospheric transport of alpha-HCH for the 1990s is well described by the model.

A new turbulence-based model for sand transport

Science.gov (United States)

Mayaud, Jerome; Wiggs, Giles; Bailey, Richard

2016-04-01

Knowledge of the changing rate of sediment flux in space and time is essential for quantifying surface erosion and deposition in desert landscapes. While many aeolian studies have relied on time-averaged parameters such as wind velocity (U) and wind shear velocity (u*) to determine sediment flux, there is increasing evidence that high-frequency turbulence is an important driving force behind the entrainment and transport of sand. However, turbulence has yet to be incorporated into a functional sand transport model that can be used for predictive purposes. In this study we present a new transport model (the 'turbulence model') that accounts for high-frequency variations in the horizontal (u) and vertical (w) components of wind flow. The turbulence model is fitted to wind velocity and sediment transport data from a field experiment undertaken in Namibia's Skeleton Coast National Park, and its performance at three temporal resolutions (10 Hz, 1 Hz, 1 min) is compared to two existing models that rely on time-averaged wind velocity data (Radok, 1977; Dong et al., 2003). The validity of the three models is analysed under a variety of saltation conditions, using a 2-hour (1 Hz measurement resolution) dataset from the Skeleton Coast and a 5-hour (1 min measurement resolution) dataset from the southwestern Kalahari Desert. The turbulence model is shown to outperform the Radok and Dong models when predicting total saltation count over the three experimental periods. For all temporal resolutions presented in this study (10 Hz-10 min), the turbulence model predicted total saltation count to within at least 0.34%, whereas the Radok and Dong models over- or underestimated total count by up to 5.50% and 20.53% respectively. The strong performance of the turbulence model can be attributed to a lag in mass flux response built into its formulation, which can be adapted depending on the temporal resolution of investigation. This accounts for the inherent lag within the physical

Model for radionuclide transport in running waters

International Nuclear Information System (INIS)

Jonsson, Karin; Elert, Mark

2005-11-01

Two sites in Sweden are currently under investigation by SKB for their suitability as places for deep repository of radioactive waste, the Forsmark and Simpevarp/Laxemar area. As a part of the safety assessment, SKB has formulated a biosphere model with different sub-models for different parts of the ecosystem in order to be able to predict the dose to humans following a possible radionuclide discharge from a future deep repository. In this report, a new model concept describing radionuclide transport in streams is presented. The main difference from the previous model for running water used by SKB, where only dilution of the inflow of radionuclides was considered, is that the new model includes parameterizations also of the exchange processes present along the stream. This is done in order to be able to investigate the effect of the retention on the transport and to be able to estimate the resulting concentrations in the different parts of the system. The concentrations determined with this new model could later be used for order of magnitude predictions of the dose to humans. The presented model concept is divided in two parts, one hydraulic and one radionuclide transport model. The hydraulic model is used to determine the flow conditions in the stream channel and is based on the assumption of uniform flow and quasi-stationary conditions. The results from the hydraulic model are used in the radionuclide transport model where the concentration is determined in the different parts of the stream ecosystem. The exchange processes considered are exchange with the sediments due to diffusion, advective transport and sedimentation/resuspension and uptake of radionuclides in biota. Transport of both dissolved radionuclides and sorbed onto particulates is considered. Sorption kinetics in the stream water phase is implemented as the time scale of the residence time in the stream water probably is short in comparison to the time scale of the kinetic sorption. In the sediment

Model for radionuclide transport in running waters

Energy Technology Data Exchange (ETDEWEB)

Jonsson, Karin; Elert, Mark [Kemakta Konsult AB, Stockholm (Sweden)

2005-11-15

Two sites in Sweden are currently under investigation by SKB for their suitability as places for deep repository of radioactive waste, the Forsmark and Simpevarp/Laxemar area. As a part of the safety assessment, SKB has formulated a biosphere model with different sub-models for different parts of the ecosystem in order to be able to predict the dose to humans following a possible radionuclide discharge from a future deep repository. In this report, a new model concept describing radionuclide transport in streams is presented. The main difference from the previous model for running water used by SKB, where only dilution of the inflow of radionuclides was considered, is that the new model includes parameterizations also of the exchange processes present along the stream. This is done in order to be able to investigate the effect of the retention on the transport and to be able to estimate the resulting concentrations in the different parts of the system. The concentrations determined with this new model could later be used for order of magnitude predictions of the dose to humans. The presented model concept is divided in two parts, one hydraulic and one radionuclide transport model. The hydraulic model is used to determine the flow conditions in the stream channel and is based on the assumption of uniform flow and quasi-stationary conditions. The results from the hydraulic model are used in the radionuclide transport model where the concentration is determined in the different parts of the stream ecosystem. The exchange processes considered are exchange with the sediments due to diffusion, advective transport and sedimentation/resuspension and uptake of radionuclides in biota. Transport of both dissolved radionuclides and sorbed onto particulates is considered. Sorption kinetics in the stream water phase is implemented as the time scale of the residence time in the stream water probably is short in comparison to the time scale of the kinetic sorption. In the sediment

Sustainable logistics and transportation optimization models and algorithms

CERN Document Server

Gakis, Konstantinos; Pardalos, Panos

2017-01-01

Focused on the logistics and transportation operations within a supply chain, this book brings together the latest models, algorithms, and optimization possibilities. Logistics and transportation problems are examined within a sustainability perspective to offer a comprehensive assessment of environmental, social, ethical, and economic performance measures. Featured models, techniques, and algorithms may be used to construct policies on alternative transportation modes and technologies, green logistics, and incentives by the incorporation of environmental, economic, and social measures. Researchers, professionals, and graduate students in urban regional planning, logistics, transport systems, optimization, supply chain management, business administration, information science, mathematics, and industrial and systems engineering will find the real life and interdisciplinary issues presented in this book informative and useful.

Transport energy demand modeling of South Korea using artificial neural network

International Nuclear Information System (INIS)

Geem, Zong Woo

2011-01-01

Artificial neural network models were developed to forecast South Korea's transport energy demand. Various independent variables, such as GDP, population, oil price, number of vehicle registrations, and passenger transport amount, were considered and several good models (Model 1 with GDP, population, and passenger transport amount; Model 2 with GDP, number of vehicle registrations, and passenger transport amount; and Model 3 with oil price, number of vehicle registrations, and passenger transport amount) were selected by comparing with multiple linear regression models. Although certain regression models obtained better R-squared values than neural network models, this does not guarantee the fact that the former is better than the latter because root mean squared errors of the former were much inferior to those of the latter. Also, certain regression model had structural weakness based on P-value. Instead, neural network models produced more robust results. Forecasted results using the neural network models show that South Korea will consume around 37 MTOE of transport energy in 2025. - Highlights: → Transport energy demand of South Korea was forecasted using artificial neural network. → Various variables (GDP, population, oil price, number of registrations, etc.) were considered. → Results of artificial neural network were compared with those of multiple linear regression.

Nonstationary porosity evolution in mixing zone in coastal carbonate aquifer using an alternative modeling approach.

Science.gov (United States)

Laabidi, Ezzeddine; Bouhlila, Rachida

2015-07-01

In the last few decades, hydrogeochemical problems have benefited from the strong interest in numerical modeling. One of the most recognized hydrogeochemical problems is the dissolution of the calcite in the mixing zone below limestone coastal aquifer. In many works, this problem has been modeled using a coupling algorithm between a density-dependent flow model and a geochemical model. A related difficulty is that, because of the high nonlinearity of the coupled set of equations, high computational effort is needed. During calcite dissolution, an increase in permeability can be identified, which can induce an increase in the penetration of the seawater into the aquifer. The majority of the previous studies used a fully coupled reactive transport model in order to model such problem. Romanov and Dreybrodt (J Hydrol 329:661-673, 2006) have used an alternative approach to quantify the porosity evolution in mixing zone below coastal carbonate aquifer at steady state. This approach is based on the analytic solution presented by Phillips (1991) in his book Flow and Reactions in Permeable Rock, which shows that it is possible to decouple the complex set of equation. This equation is proportional to the square of the salinity gradient, which can be calculated using a density driven flow code and to the reaction rate that can be calculated using a geochemical code. In this work, this equation is used in nonstationary step-by-step regime. At each time step, the quantity of the dissolved calcite is quantified, the change of porosity is calculated, and the permeability is updated. The reaction rate, which is the second derivate of the calcium equilibrium concentration in the equation, is calculated using the PHREEQC code (Parkhurst and Apello 1999). This result is used in GEODENS (Bouhlila 1999; Bouhlila and Laabidi 2008) to calculate change of the porosity after calculating the salinity gradient. For the next time step, the same protocol is used but using the updated porosity

Modelling activity transport behavior in PWR plant

International Nuclear Information System (INIS)

Henshaw, Jim; McGurk, John; Dickinson, Shirley; Burrows, Robert; Hinds, Kelvin; Hussey, Dennis; Deshon, Jeff; Barrios Figueras, Joan Pau; Maldonado Sanchez, Santiago; Fernandez Lillo, Enrique; Garbett, Keith

2012-09-01

The activation and transport of corrosion products around a PWR circuit is a major concern to PWR plant operators as these may give rise to high personnel doses. The understanding of what controls dose rates on ex-core surfaces and shutdown releases has improved over the years but still several questions remain unanswered. For example the relative importance of particle and soluble deposition in the core to activity levels in the plant is not clear. Wide plant to plant and cycle to cycle variations are noted with no apparent explanations why such variations are observed. Over the past few years this group have been developing models to simulate corrosion product transport around a PWR circuit. These models form the basis for the latest version of the BOA code and simulate the movement of Fe and Ni around the primary circuit. Part of this development is to include the activation and subsequent transport of radioactive species around the circuit and this paper describes some initial modelling work in this area. A simple model of activation, release and deposition is described and then applied to explain the plant behaviour at Sizewell B and Vandellos II. This model accounts for activation in the core, soluble and particulate activity movement around the circuit and for activity capture ex-core on both the inner and outer oxides. The model gives a reasonable comparison with plant observations and highlights what controls activity transport in these plants and importantly what factors can be ignored. (authors)

The thermoballistic transport model a novel approach to charge carrier transport in semiconductors

CERN Document Server

Lipperheide, Reinhard

2014-01-01

The book presents a comprehensive survey of the thermoballistic approach to charge carrier transport in semiconductors. This semi-classical approach, which the authors have developed over the past decade, bridges the gap between the opposing drift-diffusion and ballistic  models of carrier transport. While incorporating basic features of the latter two models, the physical concept underlying the thermoballistic approach constitutes a novel, unifying scheme. It is based on the introduction of "ballistic configurations" arising from a random partitioning of the length of a semiconducting sample into ballistic transport intervals. Stochastic averaging of the ballistic carrier currents over the ballistic configurations results in a position-dependent thermoballistic current, which is the key element of the thermoballistic concept and forms  the point of departure for the calculation of all relevant transport properties. In the book, the thermoballistic concept and its implementation are developed in great detai...

Numerical modelling of ion transport in flames

KAUST Repository

Han, Jie

2015-10-20

This paper presents a modelling framework to compute the diffusivity and mobility of ions in flames. The (n, 6, 4) interaction potential is adopted to model collisions between neutral and charged species. All required parameters in the potential are related to the polarizability of the species pair via semi-empirical formulas, which are derived using the most recently published data or best estimates. The resulting framework permits computation of the transport coefficients of any ion found in a hydrocarbon flame. The accuracy of the proposed method is evaluated by comparing its predictions with experimental data on the mobility of selected ions in single-component neutral gases. Based on this analysis, the value of a model constant available in the literature is modified in order to improve the model\\'s predictions. The newly determined ion transport coefficients are used as part of a previously developed numerical approach to compute the distribution of charged species in a freely propagating premixed lean CH4/O2 flame. Since a significant scatter of polarizability data exists in the literature, the effects of changes in polarizability on ion transport properties and the spatial distribution of ions in flames are explored. Our analysis shows that changes in polarizability propagate with decreasing effect from binary transport coefficients to species number densities. We conclude that the chosen polarizability value has a limited effect on the ion distribution in freely propagating flames. We expect that the modelling framework proposed here will benefit future efforts in modelling the effect of external voltages on flames. Supplemental data for this article can be accessed at http://dx.doi.org/10.1080/13647830.2015.1090018. © 2015 Taylor & Francis.

Hydrogeochemical and stream-sediment reconnaissance, orientation study, Ouachita Mountain area, Arkansas. National Uranium Resource Evaluation Program

International Nuclear Information System (INIS)

Steele, K.F.

1982-08-01

A hydrogeochemical ground water orientation study was conducted in the multi-mineralized area of the Ouachita Mountains, Arkansas in order to evaluate the usefulness of ground water as a sampling medium for uranium exploration in similar areas. Ninety-three springs and nine wells were sampled in Clark, Garland, Hot Springs, Howard, Montgomery, Pike, Polk, and Sevier Counties. Manganese, barite, celestite, cinnabar, stibnite, copper, lead, and zinc are present. The following parameters were determined: pH, conductivity, alkalinity, U, Br, Cl, F, He, Mn, Na, V, Al, Dy, NO 3 , NH 3 , SO 4 , and PO 4 . The minerals appear to significantly affect the chemistry of the ground water. This report is issued in draft form, without detailed technical and copy editing. This was done to make the report available to the public before the end of the National Uranium Resource Evaluation

Hydrogeochemical characterization and groundwater quality assessment in intruded coastal brine aquifers (Laizhou Bay, China).

Science.gov (United States)

Zhang, Xiaoying; Miao, Jinjie; Hu, Bill X; Liu, Hongwei; Zhang, Hanxiong; Ma, Zhen

2017-09-01

The aquifer in the coastal area of the Laizhou Bay is affected by salinization processes related to intense groundwater exploitation for brine resource and for agriculture irrigation during the last three decades. As a result, the dynamic balances among freshwater, brine, and seawater have been disturbed and the quality of groundwater has deteriorated. To fully understand the groundwater chemical distribution and evolution in the regional aquifers, hydrogeochemical and isotopic studies have been conducted based on the water samples from 102 observation wells. Groundwater levels and salinities in four monitoring wells are as well measured to inspect the general groundwater flow and chemical patterns and seasonal variations. Chemical components such as Na + , K + , Ca 2+ , Mg 2+ , Sr 2+ , Cl - , SO 4 2- , HCO 3 - , NO 3 - , F - , and TDS during the same period are analyzed to explore geochemical evolution, water-rock interactions, sources of salt, nitrate, and fluoride pollution in fresh, brackish, saline, and brine waters. The decreased water levels without typical seasonal variation in the southeast of the study area confirm an over-exploitation of groundwater. The hydrogeochemical characteristics indicate fresh-saline-brine-saline transition pattern from inland to coast where evaporation is a vital factor to control the chemical evolution. The cation exchange processes are occurred at fresh-saline interfaces of mixtures along the hydraulic gradient. Meanwhile, isotopic data indicate that the brine in aquifers was either originated from older meteoric water with mineral dissolution and evaporation or repeatedly evaporation of retained seawater with fresher water recharge and mixing in geological time. Groundwater suitability for drinking is further evaluated according to water quality standard of China. Results reveal high risks of nitrate and fluoride contamination. The elevated nitrate concentration of 560 mg/L, which as high as 28 times of the standard content

Coupling of transport and geochemical models

International Nuclear Information System (INIS)

Noy, D.J.

1986-01-01

This report considers mass transport in the far-field of a radioactive waste repository, and detailed geochemical modelling of the ground-water in the near-field. A parallel approach to this problem of coupling transport and geochemical codes is the subject of another CEC report (ref. EUR 10226). Both studies were carried out in the framework of the CEC project MIRAGE. (Migration of radionuclides in the geosphere)

Posiva safety case hydrogeochemical evolution of the Olkiluoto site

Energy Technology Data Exchange (ETDEWEB)

Trinchero, P.; Roman-Ross, G.; Maia, F.; Molinero, J. [Amphos 21 Consulting S.L., Barcelona (Spain)

2014-03-15

The goal of the present work is to assess the hydrochemical evolution and related changes in the buffering capacity of the Olkiluoto site using reactive transport models. The analysis covers a number of operational-related and climatic-related modelling periods that take place during a glacial cycle; namely, the present conditions with the open repository (Operational Period), the post-closure conditions (Temperate Period) and a stage of the glacial cycle representative of the ice sheet retreat phase (Melting Period). With the aim of reproducing the interplay between the hydrodynamic and geochemical processes, the reactive transport calculations summarised in this document integrate the results of a hydrogeological model with a number of geochemical reactions whose parameterisation relies on previous site investigation studies. The conceptual model on which the study is based, assumes that the hydrochemical evolution of the groundwater at repository depth is the result of infiltration processes from the surface of the domain to the repository. The infiltration occurs along flowpaths through deformation zones and fractures in the bedrock. The infiltrating water, in turn, undergo geochemical reactions with the rock and minerals, namely calcite and iron sulphide precipitation/dissolution, kinetic dissolution of aluminosilicates, cation exchange and aqueous redox reactions. Mass exchange between the transmissive fractures and the low permeability matrix is simulated using a dual porosity approach for the Temperate and Melting Periods. On the contrary, the Operational Period, which is characterised by high hydraulic gradients with advection being the dominant transport mechanism, is simulated using a single porosity model. In all the reactive transport simulations denoted as 'Base Case', pyrite is assumed to be the main iron sulphide mineral in the fracture filling. A set of sensitivity simulations, denoted as 'Variant Case', has been defined where

Hydrogeochemical contrast between brown and grey sand aquifers in shallow depth of Bengal Basin: consequences for sustainable drinking water supply.

Science.gov (United States)

Biswas, Ashis; Nath, Bibhash; Bhattacharya, Prosun; Halder, Dipti; Kundu, Amit K; Mandal, Ujjal; Mukherjee, Abhijit; Chatterjee, Debashis; Mörth, Carl-Magnus; Jacks, Gunnar

2012-08-01

Delineation of safe aquifer(s) that can be targeted by cheap drilling technology for tubewell (TW) installation becomes highly imperative to ensure access to safe and sustainable drinking water sources for the arsenic (As) affected population in Bengal Basin. This study investigates the potentiality of brown sand aquifers (BSA) as a safe drinking water source by characterizing its hydrogeochemical contrast to grey sand aquifers (GSA) within shallow depth (water guidelines, which warrants rigorous assessment of attendant health risk for Mn prior to considering mass scale exploitation of the BSA for possible sustainable drinking water supply. Copyright © 2012 Elsevier B.V. All rights reserved.

Instantaneous sediment transport model for asymmetric oscillatory sheet flow.

Directory of Open Access Journals (Sweden)

Xin Chen

Full Text Available On the basis of advanced concentration and velocity profiles above a mobile seabed, an instantaneous analytical model is derived for sediment transport in asymmetric oscillatory flow. The applied concentration profile is obtained from the classical exponential law based on mass conservation, and asymmetric velocity profile is developed following the turbulent boundary layer theory and the asymmetric wave theory. The proposed model includes two parts: the basic part that consists of erosion depth and free stream velocity, and can be simplified to the total Shields parameter power 3/2 in accordance with the classical empirical models, and the extra vital part that consists of phase-lead, boundary layer thickness and erosion depth. The effects of suspended sediment, phase-lag and asymmetric boundary layer development are considered particularly in the model. The observed instantaneous transport rate proportional to different velocity exponents due to phase-lag is unified and summarised by the proposed model. Both instantaneous and half period empirical formulas are compared with the developed model, using extensive data on a wide range of flow and sediment conditions. The synchronous variation in instantaneous transport rate with free stream velocity and its decrement caused by increased sediment size are predicted correctly. Net transport rates, especially offshore transport rates with large phase-lag under velocity skewed flows, which existing instantaneous type formulas failed to predict, are predicted correctly in both direction and magnitude by the proposed model. Net sediment transport rates are affected not only by suspended sediment and phase-lag, but also by the boundary layer difference between onshore and offshore.

CEMENT TRANSPORTATION LIMITED-FLEET MODELING AND ASSIGNING TO RATED DEMANDS

Directory of Open Access Journals (Sweden)

Narjes MASHHADI BANDANI

2017-04-01

Full Text Available Transportation is an inseparable part of the supply chain, with a key role in product distribution. This role is highlighted when ratio of “the cost of transportation” to “the value of goods” such as cement is significant. Iran has recently become one of the main centers of cement production in the world. However, transportation is the most important challenge in cement distribution because of weak structure of the transportation fleet and its independent action. Independence of and lack of commitment on the part of transportation fleets to cement companies as well as lack of timely delivery due to shortage of transportation in some routes and seasons lead to customers` dissatisfaction and even market loss or lack of market development. One of the significant differences between the transportation system in Iran and that in developed countries is lack of complete productivity of the transportation fleet. It means that trucks are driver-based in Iran. This paper introduces a model considering some issues such as driver-based trucks, size of the transportation fleet based on the number of active trucks, and demand priorities in the cement company. Taking the relation between the number of active trucks and the cement company into account, this model assigns weekly demands to the transportation fleet. It also tries to minimize the delay to respond to demands and increases the efficiency of the transportation fleet. Finally, this current condition-based model is compared with two other models including “no constraints on different routes of trucks” as well as single-route model for trucks.

Integrating wildfire plume rises within atmospheric transport models

Science.gov (United States)

Mallia, D. V.; Kochanski, A.; Wu, D.; Urbanski, S. P.; Krueger, S. K.; Lin, J. C.

2016-12-01

Wildfires can generate significant pyro-convection that is responsible for releasing pollutants, greenhouse gases, and trace species into the free troposphere, which are then transported a significant distance downwind from the fire. Oftentimes, atmospheric transport and chemistry models have a difficult time resolving the transport of smoke from these wildfires, primarily due to deficiencies in estimating the plume injection height, which has been highlighted in previous work as the most important aspect of simulating wildfire plume transport. As a result of the uncertainties associated with modeled wildfire plume rise, researchers face difficulties modeling the impacts of wildfire smoke on air quality and constraining fire emissions using inverse modeling techniques. Currently, several plume rise parameterizations exist that are able to determine the injection height of fire emissions; however, the success of these parameterizations has been mixed. With the advent of WRF-SFIRE, the wildfire plume rise and injection height can now be explicitly calculated using a fire spread model (SFIRE) that is dynamically linked with the atmosphere simulated by WRF. However, this model has only been tested on a limited basis due to computational costs. Here, we will test the performance of WRF-SFIRE in addition to several commonly adopted plume parameterizations (Freitas, Sofiev, and Briggs) for the 2013 Patch Springs (Utah) and 2012 Baker Canyon (Washington) fires, for both of which observations of plume rise heights are available. These plume rise techniques will then be incorporated within a Lagrangian atmospheric transport model (STILT) in order to simulate CO and CO2 concentrations during NASA's CARVE Earth Science Airborne Program over Alaska during the summer of 2012. Initial model results showed that STILT model simulations were unable to reproduce enhanced CO concentrations produced by Alaskan fires observed during 2012. Near-surface concentrations were drastically

Hybrid transport and diffusion modeling using electron thermal transport Monte Carlo SNB in DRACO

Science.gov (United States)

Chenhall, Jeffrey; Moses, Gregory

2017-10-01

The iSNB (implicit Schurtz Nicolai Busquet) multigroup diffusion electron thermal transport method is adapted into an Electron Thermal Transport Monte Carlo (ETTMC) transport method to better model angular and long mean free path non-local effects. Previously, the ETTMC model had been implemented in the 2D DRACO multiphysics code and found to produce consistent results with the iSNB method. Current work is focused on a hybridization of the computationally slower but higher fidelity ETTMC transport method with the computationally faster iSNB diffusion method in order to maximize computational efficiency. Furthermore, effects on the energy distribution of the heat flux divergence are studied. Work to date on the hybrid method will be presented. This work was supported by Sandia National Laboratories and the Univ. of Rochester Laboratory for Laser Energetics.

Development and evaluation of global radon transport model

International Nuclear Information System (INIS)

Kojima, H.; Nagano, K.

2003-01-01

The radioactive noble gas Radon-222 ( 222 Rn) is chemically inert and is removed only by radioactive decay (T1/2=3.8 d). Its primary source is uniformly distributed over the continents and the ocean represents a secondary source of atmospheric 222 Rn. The strong contrast in source strength between continents and the ocean makes 222 Rn an ideal marker of continental air masses. Because of its simple properties, the temporal and spatial distribution of 222 Rn in the troposphere is straightforward to simulate by means of atmospheric transport models. The simulation provides an intuitive visualization of the complex transport characteristics and more definite proof of phenomenon. In this paper, we present the results of an exploratory study, in which we investigated the performance of a three-dimensional transport model of the global troposphere in simulating the long range transport of 222 Rn. The transport equation has been solved by a numerical procedure based on some boundary conditions. The model structure which we have originally developed, has a horizontal resolution of 2.5deg in latitude and 2.5deg in longitude, and 10 layers in the vertical dimension. The basic computational time step used in the model runs was set to 5 min. The simulations described in this article were performed by means of a transport model driven by global objective analytical data of a time resolution of 6 h, supplied by the Japan Meteorological Agency. We focus on the west of North Pacific Ocean, were the influence of air pollution from an Asian Continent and the Japan Islands was received. For simulation experiments, radon data from some shipboard measurements on the North Pacific Ocean have been used in the present study. Figure shows time series of model prediction with different latitude distributions of radon exhalation rate and measured radon data. We find that our model consistently produce the observation. We will discuss the characteristics of the temporal and special

Modeling spin magnetization transport in a spatially varying magnetic field

Energy Technology Data Exchange (ETDEWEB)

Picone, Rico A.R., E-mail: rpicone@stmartin.edu [Department of Mechanical Engineering, University of Washington, Seattle (United States); Garbini, Joseph L. [Department of Mechanical Engineering, University of Washington, Seattle (United States); Sidles, John A. [Department of Orthopædics, University of Washington, Seattle (United States)

2015-01-15

We present a framework for modeling the transport of any number of globally conserved quantities in any spatial configuration and apply it to obtain a model of magnetization transport for spin-systems that is valid in new regimes (including high-polarization). The framework allows an entropy function to define a model that explicitly respects the laws of thermodynamics. Three facets of the model are explored. First, it is expressed as nonlinear partial differential equations that are valid for the new regime of high dipole-energy and polarization. Second, the nonlinear model is explored in the limit of low dipole-energy (semi-linear), from which is derived a physical parameter characterizing separative magnetization transport (SMT). It is shown that the necessary and sufficient condition for SMT to occur is that the parameter is spatially inhomogeneous. Third, the high spin-temperature (linear) limit is shown to be equivalent to the model of nuclear spin transport of Genack and Redfield (1975) [1]. Differences among the three forms of the model are illustrated by numerical solution with parameters corresponding to a magnetic resonance force microscopy (MRFM) experiment (Degen et al., 2009 [2]; Kuehn et al., 2008 [3]; Sidles et al., 2003 [4]; Dougherty et al., 2000 [5]). A family of analytic, steady-state solutions to the nonlinear equation is derived and shown to be the spin-temperature analog of the Langevin paramagnetic equation and Curie's law. Finally, we analyze the separative quality of magnetization transport, and a steady-state solution for the magnetization is shown to be compatible with Fenske's separative mass transport equation (Fenske, 1932 [6]). - Highlights: • A framework for modeling the transport of conserved magnetic and thermodynamic quantities in any spatial configuration. • A thermodynamically grounded model of spin magnetization transport valid in new regimes, including high-polarization. • Analysis of the separative quality of

Modeling spin magnetization transport in a spatially varying magnetic field

International Nuclear Information System (INIS)

Picone, Rico A.R.; Garbini, Joseph L.; Sidles, John A.

2015-01-01

We present a framework for modeling the transport of any number of globally conserved quantities in any spatial configuration and apply it to obtain a model of magnetization transport for spin-systems that is valid in new regimes (including high-polarization). The framework allows an entropy function to define a model that explicitly respects the laws of thermodynamics. Three facets of the model are explored. First, it is expressed as nonlinear partial differential equations that are valid for the new regime of high dipole-energy and polarization. Second, the nonlinear model is explored in the limit of low dipole-energy (semi-linear), from which is derived a physical parameter characterizing separative magnetization transport (SMT). It is shown that the necessary and sufficient condition for SMT to occur is that the parameter is spatially inhomogeneous. Third, the high spin-temperature (linear) limit is shown to be equivalent to the model of nuclear spin transport of Genack and Redfield (1975) [1]. Differences among the three forms of the model are illustrated by numerical solution with parameters corresponding to a magnetic resonance force microscopy (MRFM) experiment (Degen et al., 2009 [2]; Kuehn et al., 2008 [3]; Sidles et al., 2003 [4]; Dougherty et al., 2000 [5]). A family of analytic, steady-state solutions to the nonlinear equation is derived and shown to be the spin-temperature analog of the Langevin paramagnetic equation and Curie's law. Finally, we analyze the separative quality of magnetization transport, and a steady-state solution for the magnetization is shown to be compatible with Fenske's separative mass transport equation (Fenske, 1932 [6]). - Highlights: • A framework for modeling the transport of conserved magnetic and thermodynamic quantities in any spatial configuration. • A thermodynamically grounded model of spin magnetization transport valid in new regimes, including high-polarization. • Analysis of the separative quality of

Plasma transport simulation modelling for helical confinement systems

International Nuclear Information System (INIS)

Yamazaki, K.; Amano, T.

1992-01-01

New empirical and theoretical transport models for helical confinement systems are developed on the basis of the neoclassical transport theory, including the effect of the radial electric field and of multi-helicity magnetic components as well as the drift wave turbulence transport for electrostatic and electromagnetic modes or the anomalous semi-empirical transport. These electron thermal diffusivities are compared with experimental data from the Compact Helical System which indicate that the central transport coefficient of a plasma with electron cyclotron heating agrees with neoclassical axisymmetric value and the transport outside the half-radius is anomalous. On the other hand, the transport of plasmas with neutral beam injection heating is anomalous in the whole plasma region. This anomaly is not explained by the electrostatic drift wave turbulence models in these discharges with flat density profiles. For a detailed prediction of the plasma parameters in the Large Helical Device (LHD), 3-D equilibrium/1-D transport simulations including empirical or drift wave turbulence models are performed which suggest that the global confinement time of the LHD is determined mainly by the electron anomalous transport in the plasma edge region rather than by the helical ripple transport in the core region. Even if the ripple loss can be eliminated, the increase in global confinement is 10%. However, the rise in the central ion temperature is more than 20%. If the anomalous loss can be reduced to half of the value used in the present scaling, as is the case in the H-mode of tokamak discharges, the neoclassical ripple loss through the ion channel becomes important even in the plasma core. The 5% radial inward shift of the plasma column with respect to the major radius improves the plasma confinement and increases the fusion product by more than 50% by reducing the neoclassical asymmetric ion transport loss and increasing the plasma radius (10%). (author). 32 refs, 7 figs

Modeling of Coastal Effluent Transport: an Approach to Linking of Far-field and Near-field Models

International Nuclear Information System (INIS)

Yang, Zhaoqing; Khangaonkar, Tarang P.

2008-01-01

One of the challenges in effluent transport modeling in coastal tidal environments is the proper calculation of initial dilution in connection with the far-field transport model. In this study, an approach of external linkage of far-field and near-field effluent transport models is presented, and applied to simulate the effluent transport in the Port Angeles Harbor, Washington in the Strait of Juan de Fuca. A near-field plume model was used to calculate the effluent initial dilution and a three-dimensional (3-D) hydrodynamic model was developed to simulate the tidal circulation and far-field effluent transport in the Port Angeles Harbor. In the present study, the hydrodynamic model was driven by tides and surface winds. Observed water surface elevation and velocity data were used to calibrate the model over a period covering the neap-spring tidal cycle. The model was also validated with observed surface drogue trajectory data. The model successfully reproduced the tidal dynamics in the study area and good agreements between model results and observed data were obtained. This study demonstrated that the linkage between the near-field and far-field models in effluent transport modeling can be achieved through iteratively adjusting the model grid sizes such that the far-field modeled dilution ratio and effluent concentration in the effluent discharge model grid cell match the concentration calculated by the near-field plume model

Directions in Radiation Transport Modelling

Directory of Open Access Journals (Sweden)

P Nicholas Smith

2016-12-01

More exciting advances are on the horizon to increase the power of simulation tools. The advent of high performance computers is allowing bigger, higher fidelity models to be created, if the challenges of parallelization and memory management can be met. 3D whole core transport modelling is becoming possible. Uncertainty quantification is improving with large benefits to be gained from more accurate, less pessimistic estimates of uncertainty. Advanced graphical displays allow the user to assimilate and make sense of the vast amounts of data produced by modern modelling tools. Numerical solvers are being developed that use goal-based adaptivity to adjust the nodalisation of the system to provide the optimum scheme to achieve the user requested accuracy on the results, thus removing the need to perform costly convergence studies in space and angle etc. More use is being made of multi-physics methods in which radiation transport is coupled with other phenomena, such as thermal-hydraulics, structural response, fuel performance and/or chemistry in order to better understand their interplay in reactor cores.

Internal fracture heterogeneity in discrete fracture network modelling: Effect of correlation length and textures with connected and disconnected permeability field

Science.gov (United States)

Frampton, A.; Hyman, J.; Zou, L.

2017-12-01

Analysing flow and transport in sparsely fractured media is important for understanding how crystalline bedrock environments function as barriers to transport of contaminants, with important applications towards subsurface repositories for storage of spent nuclear fuel. Crystalline bedrocks are particularly favourable due to their geological stability, low advective flow and strong hydrogeochemical retention properties, which can delay transport of radionuclides, allowing decay to limit release to the biosphere. There are however many challenges involved in quantifying and modelling subsurface flow and transport in fractured media, largely due to geological complexity and heterogeneity, where the interplay between advective and dispersive flow strongly impacts both inert and reactive transport. A key to modelling transport in a Lagrangian framework involves quantifying pathway travel times and the hydrodynamic control of retention, and both these quantities strongly depend on heterogeneity of the fracture network at different scales. In this contribution, we present recent analysis of flow and transport considering fracture networks with single-fracture heterogeneity described by different multivariate normal distributions. A coherent triad of fields with identical correlation length and variance are created but which greatly differ in structure, corresponding to textures with well-connected low, medium and high permeability structures. Through numerical modelling of multiple scales in a stochastic setting we quantify the relative impact of texture type and correlation length against network topological measures, and identify key thresholds for cases where flow dispersion is controlled by single-fracture heterogeneity versus network-scale heterogeneity. This is achieved by using a recently developed novel numerical discrete fracture network model. Furthermore, we highlight enhanced flow channelling for cases where correlation structure continues across

Fluid transport and ion fluxes in mammalian kidney proximal tubule: a model analysis of isotonic transport

DEFF Research Database (Denmark)

Larsen, E.H.; Møbjerg, N.; Sørensen, Jens Nørkær

2006-01-01

transport similar to rat proximal tubule. Na+ recirculation is required for truly isotonic transport. The tonicity of the absorbate and the recirculation flux depend critically on ion permeabilities of interspace basement membrane. Conclusion: Our model based on solute-solvent coupling in lateral space......Aim: By mathematical modelling, we analyse conditions for near-isotonic and isotonic transport by mammalian kidney proximal tubule. Methods: The model comprises compliant lateral intercellular space (lis) and cells, and infinitely large luminal and peritubular compartments with diffusible species......: Na+, K+, Cl and an intracellular non-diffusible anion. Unknown model variables are solute concentrations, electrical potentials, volumes and hydrostatic pressures in cell and lis, and transepithelial potential. We used data mainly from rat proximal tubule to model epithelial cells and interspace...

Modelling the Transport Process in Marine Container Technology

Directory of Open Access Journals (Sweden)

Serđo Kos

2003-01-01

Full Text Available The paper introduces a mathematical problem that occursin marine container technology when programming the transportof a beforehand established number of ISO containers effectedby a full container ship from several ports of departure toseveral ports of destination at the minimum distance (time innavigation or at minimum transport costs. The application ofthe proposed model may have an effect on cost reduction incontainer transport thereby improving the operation process inmarine transport technology. The model has been tested by usinga numerical example with real data. In particular, it describesthe application of the dual variables in the analysis ofoptimum solution.

Thermal model of spent fuel transport cask

International Nuclear Information System (INIS)

Ahmed, E.E.M.; Rahman, F.A.; Sultan, G.F.; Khalil, E.E.

1996-01-01

The investigation provides a theoretical model to represent the thermal behaviour of the spent fuel elements when transported in a dry shipping cask under normal transport conditions. The heat transfer process in the spent fuel elements and within the cask are modeled which include the radiant heat transfer within the cask and the heat transfer by thermal conduction within the spent fuel element. The model considers the net radiant method for radiant heat transfer process from the inner most heated element to the surrounding spent elements. The heat conduction through fuel interior, fuel-clad interface and on clad surface are also presented. (author) 6 figs., 9 refs

Empirical particle transport model for tokamaks

International Nuclear Information System (INIS)

Petravic, M.; Kuo-Petravic, G.

1986-08-01

A simple empirical particle transport model has been constructed with the purpose of gaining insight into the L- to H-mode transition in tokamaks. The aim was to construct the simplest possible model which would reproduce the measured density profiles in the L-regime, and also produce a qualitatively correct transition to the H-regime without having to assume a completely different transport mode for the bulk of the plasma. Rather than using completely ad hoc constructions for the particle diffusion coefficient, we assume D = 1/5 chi/sub total/, where chi/sub total/ ≅ chi/sub e/ is the thermal diffusivity, and then use the κ/sub e/ = n/sub e/chi/sub e/ values derived from experiments. The observed temperature profiles are then automatically reproduced, but nontrivially, the correct density profiles are also obtained, for realistic fueling rates and profiles. Our conclusion is that it is sufficient to reduce the transport coefficients within a few centimeters of the surface to produce the H-mode behavior. An additional simple assumption, concerning the particle mean-free path, leads to a convective transport term which reverses sign a few centimeters inside the surface, as required by the H-mode density profiles

Los Alamos Scientific Laboratory approach to hydrogeochemical and stream sediment reconnaissance for uranium in the United States

International Nuclear Information System (INIS)

Bolivar, S.L.

1980-01-01

The Los Alamos Scientific Laboratory of the United States is conducting a geochemical survey for uranium in the Rocky Mountain states of New Mexico, Colorado, Wyoming, and Montana and in Alaska. This survey is part of a national hydrogeochemical and stream sediment reconnaissance in which four Department of Energy laboratories will study the uranium resources of the United States to provide data for the National Uranium Resource Evaluation program. The reconnaissance will identify areas having higher than background concentrations of uranium in ground waters, surface waters, and water-transported sediments. The reconnaissance data will be combined with data from airborne radiometric surveys and geological and geophysical investigations to provide an improved estimate for the economics and availability of nuclear fuel resources in the United States and to make information available to industry for use in the exploration and development of uranium resources. Water samples are analyzed for uranium by fluorometry which has a 0.02 parts per billion lower limit of detection. Concentrations of 12 additional elements in water are determined by plasma-source emission spectrography. All sediments are analyzed for uranium by delayed-neutron counting and a 20 parts per billion lower limit of detection. Elemental concentrations in sediments are also determined by neutron activation analysis, x-ray fluorescence, and by arc-source emission spectrography. To date, all of four Rocky Mountain states and about 80% of Alaska have been sampled. About 220,000 samples have been collected from an area of nearly 2,500,000 km 2 . The philosophy, sampling methodology, analytical techniques, and progress of the reconnaissance are described in several published pilot study, reconnaissance, and technical reports. The Los Alamos program was designed to maximize the identification of uranium in terrains of varied geography, geology, and climate

Los Alamos Scientific Laboratory approach to hydrogeochemical and stream sediment reconnaissance for uranium in the United States

Energy Technology Data Exchange (ETDEWEB)

Bolivar, S.L.

1981-01-01

The Los Alamos Scientific Laboratory of the United States is conducting a geochemical survey for uranium in the Rocky Mountain states of New Mexico, Colorado, Wyoming, and Montana and in Alaska. This survey is part of a national hydrogeochemical and stream sediment reconnaissance in which four Department of Energy laboratories will study the uranium resources of the United States to provide data for the National Uranium Resource Evaluation program. The reconnaissance will identify areas having higher than background concentrations of uranium in ground waters, surface waters, and water-transported sediments. Water and sediment samples are collected at a nominal density of one sample location per 10 km/sup 2/ except for lake areas of Alaska where the density is one sample location per 23 km/sup 2/. Water samples are analyzed for uranium by fluorometry which has a 0.02 parts per billion lower limit of detection. Concentrations of 12 additional elements in water are determined by plasma-source emission spectrography. All sediments are analyzed for uranium by delayed-neutron counting with a 20 parts per billion lower limit of detection, which is well below the range of uranium concentrations in natural sediment samples. Elemental concentrations in sediments are also determined by neutron activation analysis for 31 elements by x-ray fluorescence for 9 elements, and by arc-source emission spectrography for 2 elements. The multielement analyses provide valuable data for studies concerning pathfinder elements, environmental pollution, elemental distributions, dispersion halos, and economic ore deposits other than uranium. To date, all of four Rocky Mountain states and about 80% of Alaska have been sampled. About 220,000 samples have been collected from an area of nearly 2,500,000 km/sup 2/.

Global transportation cost modeling for long range planning

International Nuclear Information System (INIS)

Pope, R.B.; Michelhaugh, R.D.; Singley, P.T.; Lester, P.B.

1998-01-01

The U.S. Department of Energy (DOE) is preparing to perform significant remediation activities of the sites for which it is responsible. To accomplish this, it is preparing a corporate global plan focused on activities over the next decade. Significant in these planned activities is the transportation of the waste arising from the remediation. The costs of this transportation are expected to be large. To support the initial assessment of the plan, a cost-estimating model was developed, peer-reviewed against other available packaging and transportation cost data, and applied to significant number of shipping campaigns of radioactive waste. This cost-estimating model, known as the TEn-year Plan TRAnsportation cost Model (TEPTRAM), can be used to model radioactive material shipments between DOE sites or from DOE sites to non-DOE destinations. The model considers the costs for recovering and processing of the wastes, packaging the wastes for transport, and the carriage of the waste. It also provides a rough order-of-magnitude estimate of labor costs associated with preparing nd undertaking the shipments. At the user's direction, the model can also consider the cost of DOE's interactions with its external stakeholders (e.g., state and local governments and tribal entities) and the cost associated with tracking and communicating with the shipments. By considering all of these sources of costs, it provides a mechanism for assessing and comparing the costs of various waste processing and shipping campaign alternatives to help guide decision-making. Recent analyses of specific planned shipments of transuranic (TRU) waste which consider alternative packaging options are described. These analyses show that options are available for significantly reducing total costs while still satisfying regulatory requirements. (authors)

Application of rrm as behavior mode choice on modelling transportation

Science.gov (United States)

Surbakti, M. S.; Sadullah, A. F.

2018-03-01

Transportation mode selection, the first step in transportation planning process, is probably one of the most important planning elements. The development of models that can explain the preference of passengers regarding their chosen mode of public transport option will contribute to the improvement and development of existing public transport. Logit models have been widely used to determine the mode choice models in which the alternative are different transport modes. Random Regret Minimization (RRM) theory is a theory developed from the behavior to choose (choice behavior) in a state of uncertainty. During its development, the theory was used in various disciplines, such as marketing, micro economy, psychology, management, and transportation. This article aims to show the use of RRM in various modes of selection, from the results of various studies that have been conducted both in north sumatera and western Java.

Three dimensional transport model for toroidal plasmas

International Nuclear Information System (INIS)

Copenhauer, C.

1980-12-01

A nonlinear MHD model, developed for three-dimensional toroidal geometries (asymmetric) and for high β (β approximately epsilon), is used as a basis for a three-dimensional transport model. Since inertia terms are needed in describing evolving magnetic islands, the model can calculate transport, both in the transient phase before nonlinear saturation of magnetic islands and afterwards on the resistive time scale. In the β approximately epsilon ordering, the plasma does not have sufficient energy to compress the parallel magnetic field, which allows the Alfven wave to be eliminated in the reduced nonlinear equations, and the model then follows the slower time scales. The resulting perpendicular and parallel plasma drift velocities can be identified with those of guiding center theory

Interfacial and Wall Transport Models for SPACE-CAP Code

International Nuclear Information System (INIS)

Hong, Soon Joon; Choo, Yeon Joon; Han, Tae Young; Hwang, Su Hyun; Lee, Byung Chul; Choi, Hoon; Ha, Sang Jun

2009-01-01

The development project for the domestic design code was launched to be used for the safety and performance analysis of pressurized light water reactors. And CAP (Containment Analysis Package) code has been also developed for the containment safety and performance analysis side by side with SPACE. The CAP code treats three fields (gas, continuous liquid, and dispersed drop) for the assessment of containment specific phenomena, and is featured by its multidimensional assessment capabilities. Thermal hydraulics solver was already developed and now under testing of its stability and soundness. As a next step, interfacial and wall transport models was setup. In order to develop the best model and correlation package for the CAP code, various models currently used in major containment analysis codes, which are GOTHIC, CONTAIN2.0, and CONTEMPT-LT, have been reviewed. The origins of the selected models used in these codes have also been examined to find out if the models have not conflict with a proprietary right. In addition, a literature survey of the recent studies has been performed in order to incorporate the better models for the CAP code. The models and correlations of SPACE were also reviewed. CAP models and correlations are composed of interfacial heat/mass, and momentum transport models, and wall heat/mass, and momentum transport models. This paper discusses on those transport models in the CAP code

Interfacial and Wall Transport Models for SPACE-CAP Code

Energy Technology Data Exchange (ETDEWEB)

Hong, Soon Joon; Choo, Yeon Joon; Han, Tae Young; Hwang, Su Hyun; Lee, Byung Chul [FNC Tech., Seoul (Korea, Republic of); Choi, Hoon; Ha, Sang Jun [Korea Electric Power Research Institute, Daejeon (Korea, Republic of)

2009-10-15

The development project for the domestic design code was launched to be used for the safety and performance analysis of pressurized light water reactors. And CAP (Containment Analysis Package) code has been also developed for the containment safety and performance analysis side by side with SPACE. The CAP code treats three fields (gas, continuous liquid, and dispersed drop) for the assessment of containment specific phenomena, and is featured by its multidimensional assessment capabilities. Thermal hydraulics solver was already developed and now under testing of its stability and soundness. As a next step, interfacial and wall transport models was setup. In order to develop the best model and correlation package for the CAP code, various models currently used in major containment analysis codes, which are GOTHIC, CONTAIN2.0, and CONTEMPT-LT, have been reviewed. The origins of the selected models used in these codes have also been examined to find out if the models have not conflict with a proprietary right. In addition, a literature survey of the recent studies has been performed in order to incorporate the better models for the CAP code. The models and correlations of SPACE were also reviewed. CAP models and correlations are composed of interfacial heat/mass, and momentum transport models, and wall heat/mass, and momentum transport models. This paper discusses on those transport models in the CAP code.

Water quality modeling based on landscape analysis: Importance of riparian hydrology

Science.gov (United States)

Thomas Grabs

2010-01-01

Several studies in high-latitude catchments have demonstrated the importance of near-stream riparian zones as hydrogeochemical hotspots with a substantial influence on stream chemistry. An adequate representation of the spatial variability of riparian-zone processes and characteristics is the key for modeling spatiotemporal variations of stream-water quality. This...

Conceptual Model and Numerical Approaches for Unsaturated Zone Flow and Transport

International Nuclear Information System (INIS)

H.H. Liu

2004-01-01

The purpose of this model report is to document the conceptual and numerical models used for modeling unsaturated zone (UZ) fluid (water and air) flow and solute transport processes. This work was planned in ''Technical Work Plan for: Unsaturated Zone Flow Model and Analysis Report Integration'' (BSC 2004 [DIRS 169654], Sections 1.2.5, 2.1.1, 2.1.2 and 2.2.1). The conceptual and numerical modeling approaches described in this report are mainly used for models of UZ flow and transport in fractured, unsaturated rock under ambient conditions. Developments of these models are documented in the following model reports: (1) UZ Flow Model and Submodels; (2) Radionuclide Transport Models under Ambient Conditions. Conceptual models for flow and transport in unsaturated, fractured media are discussed in terms of their applicability to the UZ at Yucca Mountain. The rationale for selecting the conceptual models used for modeling of UZ flow and transport is documented. Numerical approaches for incorporating these conceptual models are evaluated in terms of their representation of the selected conceptual models and computational efficiency; and the rationales for selecting the numerical approaches used for modeling of UZ flow and transport are discussed. This report also documents activities to validate the active fracture model (AFM) based on experimental observations and theoretical developments. The AFM is a conceptual model that describes the fracture-matrix interaction in the UZ of Yucca Mountain. These validation activities are documented in Section 7 of this report regarding use of an independent line of evidence to provide additional confidence in the use of the AFM in the UZ models. The AFM has been used in UZ flow and transport models under both ambient and thermally disturbed conditions. Developments of these models are documented

Water-borne radon and hydrogeochemical based uranium exploration in Rajamundry sandstone, W. Godavari district, Andhra Pradesh

International Nuclear Information System (INIS)

Jeyagopal, A.V.; Rajaraman, H.S.; Som, Anjan

2010-01-01

The lithology and sedimentary structures of the Rajamundry Formation of the Mio-Pliocene age covering an area of 1100 sq.km. indicate that it may be a typical valley fill sediment. It is about 600 m thick comprising sandstone and clay with lignite as the main lithounits. It is continental in onshore and marine in the offshore and is in contact with Gondwana sediments and Rajamundry traps. Tertiary sandstones are important hosts for uranium mineralisation. The reducing gas (Methane or other volatile hydrocarbon) moving to uraniferous oxidising water has precipitated uranium in the sediments in South Texas and Northwest Colorado, USA: (a) along faults, (b) above petroliferous aquifers, (c) vertically above hydrocarbon accumulations and (d) oil-water interface at hydrocarbon accumulations i.e., at the points of introduction of reducent into oxidising ground waters. In this context, Rajamundry sandstone lying above the natural gas and petroleum bearing Krishna Godavari basin with faults is an important geological setting for uranium mineralisation. The exploration strategies of hydrogeochemical survey and water-borne Radon (Rn) surveys were selected in this soil-covered area. Hydrogeochemical survey carried out in the Rajamundry sandstone has brought out four hydro-uranium anomalous zones with water samples (10-45ppb) falling around Kadiyadda, Madhavaram, Erramalla and Chinna Malapalle areas of West Godavari district, Andhra Pradesh. The zones vary from 9 to 24 sq km area. Water-borne Radon was utilized as a tool for exploration of uranium in this soil covered terrain. Rn contours cluster around two zones around Kadiyadda and SW of Gollagudem wherein the Rn value is >60 counts/50 sec/500 ml. These Rn anomalies fall within the above mentioned hydrouranium anomalous zones. Gamma-ray logging of private bore wells has recorded relatively higher radioactivity in Kommugudem, which also falls in the high hydrouranium - high waterborne radon zone. These data and

Routing and Scheduling Optimization Model of Sea Transportation

Science.gov (United States)

barus, Mika debora br; asyrafy, Habib; nababan, Esther; mawengkang, Herman

2018-01-01

This paper examines the routing and scheduling optimization model of sea transportation. One of the issues discussed is about the transportation of ships carrying crude oil (tankers) which is distributed to many islands. The consideration is the cost of transportation which consists of travel costs and the cost of layover at the port. Crude oil to be distributed consists of several types. This paper develops routing and scheduling model taking into consideration some objective functions and constraints. The formulation of the mathematical model analyzed is to minimize costs based on the total distance visited by the tanker and minimize the cost of the ports. In order for the model of the problem to be more realistic and the cost calculated to be more appropriate then added a parameter that states the multiplier factor of cost increases as the charge of crude oil is filled.

Site descriptive modelling Forsmark, stage 2.2. A fracture domain concept as a basis for the statistical modelling of fractures and minor deformation zones, and interdisciplinary coordination

Energy Technology Data Exchange (ETDEWEB)

Olofsson, Isabelle; Simeonov, Assen [Swedish Nuclear Fuel and Waste Manageme nt Co., Stockholm (Sweden); Stephens, Michael [Geological Survey of Sweden (SGU), U ppsala (Sweden); Follin, Sven [SF GeoLogic AB, Taeby (Sweden); Nilsson, Ann-Chatrin [G eosigma AB, Uppsala (Sweden); Roeshoff, Kennert; Lindberg, Ulrika; Lanaro, Flavio [Bergbygg konsult AB, Haesselby (Sweden); Fredriksson, Anders; Persson, Lars [Golder Associat es AB (Sweden)

2007-04-15

The Swedish Nuclear Fuel and Waste Management Company (SKB) is undertaking site characterization at two different locations, Forsmark and Simpevarp/Laxemar, with the objective of siting a final waste repository at depth for spent nuclear fuel. The programme is built upon the development of site descriptive models after each data freeze. This report describes the first attempt to define fracture domains for the Forsmark site modelling in stage 2.2. Already during model version 1.2 at Forsmark, significant spatial variability in the fracture pattern was observed. The variability appeared to be so significant that it provoked the need for a subdivision of the model volume for the treatment of geological and hydrogeological data into sub-volumes. Subsequent analyses of data collected up to data freeze 2.1 led to a better understanding of the site and a concept for the definition of fracture domains based on geological characteristics matured. The main objectives of this report are to identify and describe fracture domains at the site on the basis of geological data and to compile hydrogeological, hydrogeochemical and rock mechanics data within each fracture domain and address the implications of this integration activity. On the basis of borehole data, six fracture domains (FFM01-FFM06) have been recognized inside and immediately around the candidate volume. Three of these domains (FFM01, FFM02 and FFM06) lie inside the target volume for a potential repository in the northwestern part of the candidate area, and need to be addressed in the geological DFN modelling work. The hydrogeological data support the subdivision of the bedrock into fracture domains FFM01, FFM02 and FFM03. Few or no data are available for the other three domains. The hydrogeochemical data also support the subdivision into fracture domains FFM01 and FFM02. Since few data are available from the bedrock between deformation zones inside FFM03, there is little information on the hydrogeochemical

Worldwide transportation/energy demand, 1975-2000. Revised Variflex model projections

Energy Technology Data Exchange (ETDEWEB)

Ayres, R.U.; Ayres, L.W.

1980-03-01

The salient features of the transportation-energy relationships that characterize the world of 1975 are reviewed, and worldwide (34 countries) long-range transportation demand by mode to the year 2000 is reviewed. A worldwide model is used to estimate future energy demand for transportation. Projections made by the forecasting model indicate that in the year 2000, every region will be more dependent on petroleum for the transportation sector than it was in 1975. This report is intended to highlight certain trends and to suggest areas for further investigation. Forecast methodology and model output are described in detail in the appendices. The report is one of a series addressing transportation energy consumption; it supplants and replaces an earlier version published in October 1978 (ORNL/Sub-78/13536/1).

UNCERTAINTY SUPPLY CHAIN MODEL AND TRANSPORT IN ITS DEPLOYMENTS

Directory of Open Access Journals (Sweden)

Fabiana Lucena Oliveira

2014-05-01

Full Text Available This article discusses the Model Uncertainty of Supply Chain, and proposes a matrix with their transportation modes best suited to their chains. From the detailed analysis of the matrix of uncertainty, it is suggested transportation modes best suited to the management of these chains, so that transport is the most appropriate optimization of the gains previously proposed by the original model, particularly when supply chains are distant from suppliers of raw materials and / or supplies.Here we analyze in detail Agile Supply Chains, which is a result of Uncertainty Supply Chain Model, with special attention to Manaus Industrial Center. This research was done at Manaus Industrial Pole, which is a model of industrial agglomerations, based in Manaus, State of Amazonas (Brazil, which contemplates different supply chains and strategies sharing same infrastructure of transport, handling and storage and clearance process and uses inbound for suppliers of raw material.  The state of art contemplates supply chain management, uncertainty supply chain model, agile supply chains, Manaus Industrial Center (MIC and Brazilian legislation, as a business case, and presents concepts and features, of each one. The main goal is to present and discuss how transport is able to support Uncertainty Supply Chain Model, in order to complete management model. The results obtained confirms the hypothesis of integrated logistics processes are able to guarantee attractivity for industrial agglomerations, and open discussions when the suppliers are far from the manufacturer center, in a logistics management.

A turbulent transport network model in MULTIFLUX coupled with TOUGH2

International Nuclear Information System (INIS)

Danko, G.; Bahrami, D.; Birkholzer, J.T.

2011-01-01

A new numerical method is described for the fully iterated, conjugate solution of two discrete submodels, involving (a) a transport network model for heat, moisture, and airflows in a high-permeability, air-filled cavity; and (b) a variably saturated fractured porous medium. The transport network submodel is an integrated-parameter, computational fluid dynamics solver, describing the thermal-hydrologic transport processes in the flow channel system of the cavity with laminar or turbulent flow and convective heat and mass transport, using MULTIFLUX. The porous medium submodel, using TOUGH2, is a solver for the heat and mass transport in the fractured rock mass. The new model solution extends the application fields of TOUGH2 by integrating it with turbulent flow and transport in a discrete flow network system. We present demonstrational results for a nuclear waste repository application at Yucca Mountain with the most realistic model assumptions and input parameters including the geometrical layout of the nuclear spent fuel and waste with variable heat load for the individual containers. The MULTIFLUX and TOUGH2 model elements are fully iterated, applying a programmed reprocessing of the Numerical Transport Code Functionalization model-element in an automated Outside Balance Iteration loop. The natural, convective airflow field and the heat and mass transport in a representative emplacement drift during postclosure are explicitly solved in the new model. The results demonstrate that the direction and magnitude of the air circulation patterns and all transport modes are strongly affected by the heat and moisture transport processes in the surrounding rock, justifying the need for a coupled, fully iterated model solution such as the one presented in the paper.

Discrete element modelling of bedload transport

Science.gov (United States)

Loyer, A.; Frey, P.

2011-12-01

Discrete element modelling (DEM) has been widely used in solid mechanics and in granular physics. In this type of modelling, each individual particle is taken into account and intergranular interactions are modelled with simple laws (e.g. Coulomb friction). Gravity and contact forces permit to solve the dynamical behaviour of the system. DEM is interesting to model configurations and access to parameters not directly available in laboratory experimentation, hence the term "numerical experimentations" sometimes used to describe DEM. DEM was used to model bedload transport experiments performed at the particle scale with spherical glass beads in a steep and narrow flume. Bedload is the larger material that is transported on the bed on stream channels. It has a great geomorphic impact. Physical processes ruling bedload transport and more generally coarse-particle/fluid systems are poorly known, arguably because granular interactions have been somewhat neglected. An existing DEM code (PFC3D) already computing granular interactions was used. We implemented basic hydrodynamic forces to model the fluid interactions (buoyancy, drag, lift). The idea was to use the minimum number of ingredients to match the experimental results. Experiments were performed with one-size and two-size mixtures of coarse spherical glass beads entrained by a shallow turbulent and supercritical water flow down a steep channel with a mobile bed. The particle diameters were 4 and 6mm, the channel width 6.5mm (about the same width as the coarser particles) and the channel inclination was typically 10%. The water flow rate and the particle rate were kept constant at the upstream entrance and adjusted to obtain bedload transport equilibrium. Flows were filmed from the side by a high-speed camera. Using image processing algorithms made it possible to determine the position, velocity and trajectory of both smaller and coarser particles. Modelled and experimental particle velocity and concentration depth

Erosion and Sediment Transport Modelling in Shallow Waters: A Review on Approaches, Models and Applications

Directory of Open Access Journals (Sweden)

Mohammad Hajigholizadeh

2018-03-01

Full Text Available The erosion and sediment transport processes in shallow waters, which are discussed in this paper, begin when water droplets hit the soil surface. The transport mechanism caused by the consequent rainfall-runoff process determines the amount of generated sediment that can be transferred downslope. Many significant studies and models are performed to investigate these processes, which differ in terms of their effecting factors, approaches, inputs and outputs, model structure and the manner that these processes represent. This paper attempts to review the related literature concerning sediment transport modelling in shallow waters. A classification based on the representational processes of the soil erosion and sediment transport models (empirical, conceptual, physical and hybrid is adopted, and the commonly-used models and their characteristics are listed. This review is expected to be of interest to researchers and soil and water conservation managers who are working on erosion and sediment transport phenomena in shallow waters. The paper format should be helpful for practitioners to identify and generally characterize the types of available models, their strengths and their basic scope of applicability.

Erosion and Sediment Transport Modelling in Shallow Waters: A Review on Approaches, Models and Applications.

Science.gov (United States)

Hajigholizadeh, Mohammad; Melesse, Assefa M; Fuentes, Hector R

2018-03-14

The erosion and sediment transport processes in shallow waters, which are discussed in this paper, begin when water droplets hit the soil surface. The transport mechanism caused by the consequent rainfall-runoff process determines the amount of generated sediment that can be transferred downslope. Many significant studies and models are performed to investigate these processes, which differ in terms of their effecting factors, approaches, inputs and outputs, model structure and the manner that these processes represent. This paper attempts to review the related literature concerning sediment transport modelling in shallow waters. A classification based on the representational processes of the soil erosion and sediment transport models (empirical, conceptual, physical and hybrid) is adopted, and the commonly-used models and their characteristics are listed. This review is expected to be of interest to researchers and soil and water conservation managers who are working on erosion and sediment transport phenomena in shallow waters. The paper format should be helpful for practitioners to identify and generally characterize the types of available models, their strengths and their basic scope of applicability.

Uranium hydrogeochemical and stream sediment reconnaissance of the White Sulfur Springs NTMS quadrangle, Montana

International Nuclear Information System (INIS)

1981-11-01

This report presents results of a Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) of the White Sulphur Springs NTMS quadrangle, Montana. In addition to this abbreviated data release, more complete data are available to the public in machine-readable form. Presented in this data release are location data, field analyses, and laboratory analyses of several different sample media. For the sake of brevity, many field site observations have not been included in this volume; these data are, however, available on the magnetic tape. Appendices A through C describe the sample media and summarize the analytical results for each medium. The data have been subdivided by one of the Los Alamos National Laboratory sorting programs of Zinkl and others (1981a) into groups of stream-sediment, stream-water, and ground-water samples. For each group which contains a sufficient number of observations, statistical tables, tables of raw data, and 1:1,000,000 scale maps of pertinent elements have been included in this report. Also included are maps showing results of multivariate statistical analyses

Multiscale modeling of transport of grains through granular assemblies

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Tejada Ignacio G

2017-01-01

Full Text Available We investigate the transport of moderately large passive particles through granular assemblies caused by seeping flows. This process can only be described by highly nonlinear continuum models, since the local permeability, the advection and dispersion mechanisms are strongly determined by the concentration of transported particles. Particles may sometimes get temporally trapped and thus proper kinetic mass transfer models are required. The mass transfer depends on the complexity of the porous medium, the kind of interaction forces and the concentration of transported particles. We study these two issues by means of numerical and laboratory experiments. In the laboratory we use an oedo-permeameter to force sand grains to move through a gravel bed under conditions of constant hydraulic pressure drop. To understand the process, numerical experiments were performed to approach particle transport at the grain scale with a fully coupled method. The DEM-PFV combines the discrete element method with a pore scale finite volume formulation to solve the interstitial fluid flow and particle transport problems. These experiments help us to set up a continuum transport model that can be used in a boundary value problem.

Critical review: Radionuclide transport, sediment transport, and water quality mathematical modeling; and radionuclide adsorption/desorption mechanisms

Energy Technology Data Exchange (ETDEWEB)

Onishi, Y.; Serne, R.J.; Arnold, E.M.; Cowan, C.E.; Thompson, F.L. [Pacific Northwest Lab., Richland, WA (United States)

1981-01-01

This report describes the results of a detailed literature review of radionuclide transport models applicable to rivers, estuaries, coastal waters, the Great Lakes, and impoundments. Some representatives sediment transport and water quality models were also reviewed to evaluate if they can be readily adapted to radionuclide transport modeling. The review showed that most available transport models were developed for dissolved radionuclide in rivers. These models include the mechanisms of advection, dispersion, and radionuclide decay. Since the models do not include sediment and radionuclide interactions, they are best suited for simulating short-term radionuclide migration where: (1) radionuclides have small distribution coefficients; (2) sediment concentrations in receiving water bodies are very low. Only 5 of the reviewed models include full sediment and radionuclide interactions: CHMSED developed by Fields; FETRA SERATRA, and TODAM developed by Onishi et al, and a model developed by Shull and Gloyna. The 5 models are applicable to cases where: (1) the distribution coefficient is large; (2) sediment concentrations are high; or (3) long-term migration and accumulation are under consideration. The report also discusses radionuclide absorption/desorption distribution ratios and addresses adsorption/desorption mechanisms and their controlling processes for 25 elements under surface water conditions. These elements are: Am, Sb, C, Ce, Cm, Co, Cr, Cs, Eu, I, Fe, Mn, Np, P, Pu, Pm, Ra, Ru, Sr, Tc, Th, {sup 3}H, U, Zn and Zr.

Global transportation cost modeling for long-range planning

International Nuclear Information System (INIS)

Pope, R.B.; Michelhaugh, R.D.; Singley, P.T.; Lester, P.B.

1998-02-01

The US Department of Energy (DOE) is preparing to perform significant remediation activities of the sites for which it is responsible. To accomplish this, it is preparing a corporate global plan focused on activities over the next decade. Significant in these planned activities is the transportation of the waste arising from the remediation. The costs of this transportation are expected to be large. To support the initial assessment of the plan, a cost estimating model was developed, peer-reviewed against other available packaging and transportation cost data, and applied to a significant number of shipping campaigns of radioactive waste. This cost estimating model, known as the Ten-year Plan Transportation Cost Model (TEPTRAM), can be used to model radioactive material shipments between DOE sites or from DOE sites to non-DOE destinations. The model considers the costs for (a) recovering and processing of the wastes, (b)packaging the wastes for transport, and (c) the carriage of the waste. It also provides a rough order of magnitude estimate of labor costs associated with preparing and undertaking the shipments. At the user's direction, the model can also consider the cost of DOE's interactions with its external stakeholders (e.g., state and local governments and tribal entities) and the cost associated with tracking and communicating with the shipments. By considering all of these sources of costs, it provides a mechanism for assessing and comparing the costs of various waste processing and shipping campaign alternatives to help guide decision-making. Recent analyses of specific planned shipments of transuranic (TRU) waste which consider alternative packaging options are described. These analyses show that options are available for significantly reducing total costs while still satisfying regulatory requirements

Paving the road from transport models to “new mobilities” models

DEFF Research Database (Denmark)

Wind, Simon; Jensen, Ole B.; Kaplan, Sigal

2012-01-01

For half a century, tremendous efforts have been invested in developing transport models as a decision aid for policy makers in designing effective policy interventions and deciding among costly public projects for the benefit of the population. Transport and activity-based models are often...... criticized for neglecting the “new mobilities” turn (Urry 2007, Cresswell 2006), namely multiple mobility aspects and rationales, including social, cultural, material, aesthetic and affective, in analyzing travel behavior. This paper aims at taking a tentative first step in bridging the gap between...

Impact of transport model errors on the global and regional methane emissions estimated by inverse modelling

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R. Locatelli

2013-10-01

Full Text Available A modelling experiment has been conceived to assess the impact of transport model errors on methane emissions estimated in an atmospheric inversion system. Synthetic methane observations, obtained from 10 different model outputs from the international TransCom-CH4 model inter-comparison exercise, are combined with a prior scenario of methane emissions and sinks, and integrated into the three-component PYVAR-LMDZ-SACS (PYthon VARiational-Laboratoire de Météorologie Dynamique model with Zooming capability-Simplified Atmospheric Chemistry System inversion system to produce 10 different methane emission estimates at the global scale for the year 2005. The same methane sinks, emissions and initial conditions have been applied to produce the 10 synthetic observation datasets. The same inversion set-up (statistical errors, prior emissions, inverse procedure is then applied to derive flux estimates by inverse modelling. Consequently, only differences in the modelling of atmospheric transport may cause differences in the estimated fluxes. In our framework, we show that transport model errors lead to a discrepancy of 27 Tg yr−1 at the global scale, representing 5% of total methane emissions. At continental and annual scales, transport model errors are proportionally larger than at the global scale, with errors ranging from 36 Tg yr−1 in North America to 7 Tg yr−1 in Boreal Eurasia (from 23 to 48%, respectively. At the model grid-scale, the spread of inverse estimates can reach 150% of the prior flux. Therefore, transport model errors contribute significantly to overall uncertainties in emission estimates by inverse modelling, especially when small spatial scales are examined. Sensitivity tests have been carried out to estimate the impact of the measurement network and the advantage of higher horizontal resolution in transport models. The large differences found between methane flux estimates inferred in these different configurations highly

Uranium Hydrogeochemical and Stream Sediment Reconnaissance in southwestern Montana

Energy Technology Data Exchange (ETDEWEB)

Broxton, D.E.

1978-02-01

The Los Alamos Scientific Laboratory conducted a Hydrogeochemical and Stream Sediment Reconnaissance in southwestern Montana from early August to mid-October of 1976. A total of 1240 water and 1933 sediment samples were collected from 1994 locations at a nominal density of one location per 10 km/sup 2/. The water samples were collected from streams, wells, and springs; sediment samples were taken at streams and springs. All samples were analyzed at Los Alamos for total uranium by fluorometry or delayed-neutron counting. The uranium content of water samples ranges from below the detection limit (less than 0.3 ppB) to 45.30 ppB and has a mean value of 1.40 ppB. The uranium content of the sediment samples ranges between 0.20 and 206.80 ppM and averages 6.12 ppM. The chosen uranium anomaly threshold value was 7 ppB for surface waters (streams), 9 ppB for groundwaters (wells and springs), and 25 ppM for all sediment samples. The study area consists of the following lithologic groups: Precambrian basement complex, Precambrian Belt metasediments, Paleozoic and Mesozoic shelf sediments, Cretaceous and early Tertiary volcanic and plutonic rocks, Laramide orogenic clastic sediments, and middle to late Tertiary volcanic rocks and intermontane basin sediments. Most of the anomalous water and sediment samples with well-developed dispersion trains occur in areas underlain by or adjacent to silicic plutonic rocks of the Idaho and Boulder batholiths. These anomalies may indicate the presence of uraniferous veins and pegmatites similar to those already known to exist in the area. Fewer anomalous water samples occur in areas underlain by Precambrian basement complex and Tertiary basin fill.

Uranium Hydrogeochemical and Stream Sediment Reconnaissance in southwestern Montana

International Nuclear Information System (INIS)

Broxton, D.E.

1978-02-01

The Los Alamos Scientific Laboratory conducted a Hydrogeochemical and Stream Sediment Reconnaissance in southwestern Montana from early August to mid-October of 1976. A total of 1240 water and 1933 sediment samples were collected from 1994 locations at a nominal density of one location per 10 km 2 . The water samples were collected from streams, wells, and springs; sediment samples were taken at streams and springs. All samples were analyzed at Los Alamos for total uranium by fluorometry or delayed-neutron counting. The uranium content of water samples ranges from below the detection limit (less than 0.3 ppB) to 45.30 ppB and has a mean value of 1.40 ppB. The uranium content of the sediment samples ranges between 0.20 and 206.80 ppM and averages 6.12 ppM. The chosen uranium anomaly threshold value was 7 ppB for surface waters (streams), 9 ppB for groundwaters (wells and springs), and 25 ppM for all sediment samples. The study area consists of the following lithologic groups: Precambrian basement complex, Precambrian Belt metasediments, Paleozoic and Mesozoic shelf sediments, Cretaceous and early Tertiary volcanic and plutonic rocks, Laramide orogenic clastic sediments, and middle to late Tertiary volcanic rocks and intermontane basin sediments. Most of the anomalous water and sediment samples with well-developed dispersion trains occur in areas underlain by or adjacent to silicic plutonic rocks of the Idaho and Boulder batholiths. These anomalies may indicate the presence of uraniferous veins and pegmatites similar to those already known to exist in the area. Fewer anomalous water samples occur in areas underlain by Precambrian basement complex and Tertiary basin fill

Molecular modeling of auxin transport inhibitors

International Nuclear Information System (INIS)

Gardner, G.; Black-Schaefer, C.; Bures, M.G.

1990-01-01

Molecular modeling techniques have been used to study the chemical and steric properties of auxin transport inhibitors. These bind to a specific site on the plant plasma membrane characterized by its affinity for N-1-naphthylphthalamic acid (NPA). A three-dimensional model was derived from critical features of ligands for the NPA receptor, and a suggested binding conformation is proposed. This model, along with three-dimensional structural searching techniques, was then used to search the Abbott corporate database of chemical structures. Of the 467 compounds that satisfied the search criteria, 77 representative molecules were evaluated for their ability to compete for [ 3 H]NPA binding to corn microsomal membranes. Nineteen showed activity that ranged from 16 to 85% of the maximum NPA binding. Four of the most active of these, from chemical classes not included in the original compound set, also inhibited polar auxin transport through corn coleoptile sections

Combining Inverse and Transport Modeling to Estimate Bacterial Loading and Transport in a Tidal Embayment

Directory of Open Access Journals (Sweden)

Mac Sisson

2016-11-01

Full Text Available Poquoson River is a tidal coastal embayment located along the Western Shore of the Chesapeake Bay about 4 km south of the York River mouth in the City of Poquoson and in York County, Virginia. Its drainage area has diversified land uses, including high densities of residence, agricultural, salt marsh land uses, as well as a National Wildlife Refuge. This embayment experiences elevated bacterial concentration due to excess bacterial inputs from storm water runoff, nonpoint sources, and wash off from marshes due to tide and wind-induced set-up and set-down. Bacteria can also grow in the marsh and small tributaries. It is difficult to use a traditional watershed model to simulate bacterial loading, especially in this low-lying marsh area with abundant wildlife, while runoff is not solely driven by precipitation. An inverse approach is introduced to estimate loading from unknown sources based on observations in the embayment. The estimated loadings were combined with loadings estimated from different sources (human, wildlife, agriculture, pets, etc. and input to the watershed model. The watershed model simulated long-term flow and bacterial loading and discharged to a three-dimensional transport model driven by tide, wind, and freshwater discharge. The transport model efficiently simulates the transport and fate of the bacterial concentration in the embayment and is capable of determining the loading reduction needed to improve the water quality condition of the embayment. Combining inverse, watershed, and transport models is a sound approach for simulating bacterial transport correctly in the coastal embayment with complex unknown bacterial sources, which are not solely driven by precipitation.

The secret to successful solute-transport modeling

Science.gov (United States)

Konikow, Leonard F.

2011-01-01

Modeling subsurface solute transport is difficult—more so than modeling heads and flows. The classical governing equation does not always adequately represent what we see at the field scale. In such cases, commonly used numerical models are solving the wrong equation. Also, the transport equation is hyperbolic where advection is dominant, and parabolic where hydrodynamic dispersion is dominant. No single numerical method works well for all conditions, and for any given complex field problem, where seepage velocity is highly variable, no one method will be optimal everywhere. Although we normally expect a numerically accurate solution to the governing groundwater-flow equation, errors in concentrations from numerical dispersion and/or oscillations may be large in some cases. The accuracy and efficiency of the numerical solution to the solute-transport equation are more sensitive to the numerical method chosen than for typical groundwater-flow problems. However, numerical errors can be kept within acceptable limits if sufficient computational effort is expended. But impractically long

Evaluation and modelling of a potential repository site - Olkiluoto case study

International Nuclear Information System (INIS)

Saksa, P.; Ahokas, H.; Loefman, J.; Pitkaenen, P.; Paulamaeki, S.; Snellman, M.

1998-01-01

The observations, interpretations and estimates resulting from site investigations were developed into conceptual bedrock model of the Olkiluoto area. Model development has been an interdisciplinary process and three major iterations have occurred. Geochemical sampling and a programme of electromagnetic and electrical soundings were carried out and interpreted to model occurrences of groundwater types. The parametrisation and modifications needed between geological models and ground-water flow simulation model is discussed. The latest groundwater flow modelling effort comprises the transient flow analysis taking into account the effects of density variations, the repository, post-glacial land uplift and global sea level rise. The main flow modeling result quantities (the amount, direction, velocity and routes as well as concentration of water) are used for evaluation of the investigation sites and of the preconditions for safe final disposal of spent nuclear fuel. Integration of hydrological and hydrogeochemical methods and studies has provided the primary method for investigating the evolution. Testing of flow models with hydro-geochemical information is considered to improve the hydrogeological understanding of a site and increases confidence in conceptual hydrogeological models. Bedrock model allows also comparisons to be made between its time-varying versions. The evolution of fracture frequency, fracture zone structures and hydraulic conductivity has been studied. A prediction-outcome comparison was made in selected boreholes and showed that the rock type was the easiest parameter to predict

Sediment and toxic contaminant transport modeling in coastal waters

International Nuclear Information System (INIS)

Onishi, Yasuo; Mayer, D.W.; Argo, R.S.

1982-01-01

Models are presented to estimate the migration of toxic contaminants in coastal waters. Ocean current is simulated by the vertically-averaged, finite element, two-demensional model known as CAFE-I with the Galerkin weighted residual technique. The refraction of locally generated waves or swells is simulated by the wave refraction model, LO3D. Using computed current, depth, and wave characteristics, the finite element model, FETRA, simulated sediment and contaminant transport in coastal waters, estuaries and rivers. Prior to the application of these models to the Irish Sea and other coastal waters, the finite element model, FETRA, was tested to demonstrate its ability to simulate sediment and contaminant interaction, and the mechanism governing the transport, deposition, and resuspension of contaminated sediment. Several simple equations such as the unsteady, advection-diffusion equation, the equation for noncohesive-sediment load due to wind-induced waves in offshore and surf zones, and the equation for sediment-radionuclide transport simulation were solved during the preliminary testing of the model. (Kato, T.)

Modelling transport-limited discharge capacity of lithium-sulfur cells

International Nuclear Information System (INIS)

Zhang, Teng; Marinescu, Monica; Walus, Sylwia; Offer, Gregory J.

2016-01-01

Highlights: • We modelled the rate capability of a Li-S cell based on mass-transport limitation • The model predicts a discharged Li-S cell to regain capacity upon short relaxation • Modelled rate capability and capacity recovery effect validated with measurements - Abstract: Lithium-sulfur (Li-S) battery could bring a step-change in battery technology with a potential specific energy density of 500 - 600 Wh/kg. A key challenge for further improving the specific energy-density of Li-S cells is to understand the mechanisms behind reduced sulfur utilisation at low electrolyte loadings and high discharge currents. While several Li-S models have been developed to explore the discharge mechanisms of Li-S cells, they so far fail to capture the discharge profiles at high currents. In this study, we propose that the slow ionic transport in concentrated electrolyte is limiting the rate capability of Li-S cells. This transport-limitation mechanism is demonstrated through a one-dimensional Li-S model which qualitatively captures the discharge capacities of a sulfolane-based Li-S cell at different currents. Furthermore, our model predicts that a discharged Li-S cell is able regain some capacity with a short period of relaxation. This capacity recovery phenomenon is validated experimentally for different discharge currents and relaxation durations. The transport-limited discharge behavior of Li-S cells highlights the importance of optimizing the electrolyte loading and electrolyte transport property in Li-S cells.

Modeling sheet-flow sand transport under progressive surface waves

NARCIS (Netherlands)

Kranenburg, Wouter

2013-01-01

In the near-shore zone, energetic sea waves generate sheet-flow sand transport. In present day coastal models, wave-induced sheet-flow sand transport rates are usually predicted with semi-empirical transport formulas, based on extensive research on this phenomenon in oscillatory flow tunnels.

A consistent transported PDF model for treating differential molecular diffusion

Science.gov (United States)

Wang, Haifeng; Zhang, Pei

2016-11-01

Differential molecular diffusion is a fundamentally significant phenomenon in all multi-component turbulent reacting or non-reacting flows caused by the different rates of molecular diffusion of energy and species concentrations. In the transported probability density function (PDF) method, the differential molecular diffusion can be treated by using a mean drift model developed by McDermott and Pope. This model correctly accounts for the differential molecular diffusion in the scalar mean transport and yields a correct DNS limit of the scalar variance production. The model, however, misses the molecular diffusion term in the scalar variance transport equation, which yields an inconsistent prediction of the scalar variance in the transported PDF method. In this work, a new model is introduced to remedy this problem that can yield a consistent scalar variance prediction. The model formulation along with its numerical implementation is discussed, and the model validation is conducted in a turbulent mixing layer problem.

Transport Routes Optimization Model Through Application of Fuzzy Logic

Directory of Open Access Journals (Sweden)

Ivan Bortas

2018-03-01

Full Text Available The transport policy of the European Union is based on the mission of restructuring road traffic into other and energy-favourable transport modes which have not been sufficiently represented yet. Therefore, the development of the inland waterway and rail transport, and connectivity in the intermodal transport network are development planning priorities of the European transport strategy. The aim of this research study was to apply the scientific methodology and thus analyse the factors that affect the distribution of the goods flows and by using the fuzzy logic to make an optimization model, according to the criteria of minimizing the costs and negative impact on the environment, for the selection of the optimal transport route. Testing of the model by simulation, was performed on the basis of evaluating the criteria of the influential parameters with unprecise and indefinite input parameters. The testing results show that by the distribution of the goods flow from road transport network to inland waterways or rail transport, can be predicted in advance and determine the transport route with optimal characteristics. The results of the performed research study will be used to improve the process of planning the transport service, with the aim of reducing the transport costs and environmental pollution.

NURE [National Uranium Resource Evaluation] HSSR [Hydrogeochemical and Stream Sediment Reconnaissance] Data Summary Tables, United States: Volume 2

International Nuclear Information System (INIS)

1985-01-01

This volume presents a summary of the distribution of elemental concentrations for water and sediment samples across states. Hawaii is missing from all tables since no sampling was done in that state. The following section briefly outlines the approach used by ISP in preparing these data tables. The third section contains the summary tables organized by sample type (water and sediment) and displaying elements within states and states within elements. These data summary tables show the general ranges of values present in the NURE Hydrogeochemical and Stream Sediment Reconnaissance sample data in each quadrangle or state. As with all summaries, they represent the data according to the best judgement of the professionals doing the analysis. This section gives a general description of the procedures used to produce the quadrangle summary percentiles

An Updated Site Scale Saturated Zone Ground Water Transport Model For Yucca Mountain

International Nuclear Information System (INIS)

S. Kelkar; H. Viswanathan; A. Eddebbarrh; M. Ding; P. Reimus; B. Robinson; B. Arnold; A. Meijer

2006-01-01

The Yucca Mountain site scale saturated zone transport model has been revised to incorporate the updated flow model based on a hydrogeologic framework model using the latest lithology data, increased grid resolution that better resolves the geology within the model domain, updated Kd distributions for radionuclides of interest, and updated retardation factor distributions for colloid filtration. The resulting numerical transport model is used for performance assessment predictions of radionuclide transport and to guide future data collection and modeling activities. The transport model results are validated by comparing the model transport pathways with those derived from geochemical data, and by comparing the transit times from the repository footprint to the compliance boundary at the accessible environment with those derived from 14 C-based age estimates. The transport model includes the processes of advection, dispersion, fracture flow, matrix diffusion, sorption, and colloid-facilitated transport. The transport of sorbing radionuclides in the aqueous phase is modeled as a linear, equilibrium process using the Kd model. The colloid-facilitated transport of radionuclides is modeled using two approaches: the colloids with irreversibly embedded radionuclides undergo reversible filtration only, while the migration of radionuclides that reversibly sorb to colloids is modeled with modified values for sorption coefficient and matrix diffusion coefficients. Model breakthrough curves for various radionuclides at the compliance boundary are presented along with their sensitivity to various parameters

Toward a comprehensive model of chemical transport in porous media

International Nuclear Information System (INIS)

Miller, C.W.

1983-02-01

A chemical transport model, CHEMTRN, that includes advection, dispersion/diffusion, complexation, sorption, precipitation or dissolution of solids, and the dissociation of water has been written. The transport, mass action and site constraint equations are written in a differential/algebraic form and solved simultaneously. The sorption process is modelled by either ion-exchange or surface complexation. The model has been used to investigate the applicability of a k/sub D/ model for simulating the transport of chemical species in groundwater systems, to simulate precipitation/dissolution of minerals, and to consider the effect of surface complexation on sorption

Modelling the transport system in China and evaluating the current strategies towards the sustainable transport development

DEFF Research Database (Denmark)

Liu, W.; Lund, H.; Mathiesen, B.V.

2013-01-01

in China. With this purpose in mind, a Chinese transport model has been created and three current transport strategies which are high speed railway (HSR), urban rail transit (URT) and electric vehicle (EV) were evaluated together with a reference transport system in 2020. As conservative results, 13...

Radionuclide Transport Models Under Ambient Conditions

International Nuclear Information System (INIS)

Moridis, G.; Hu, Q.

2001-01-01

The purpose of Revision 00 of this Analysis/Model Report (AMR) is to evaluate (by means of 2-D semianalytical and 3-D numerical models) the transport of radioactive solutes and colloids in the unsaturated zone (UZ) under ambient conditions from the potential repository horizon to the water table at Yucca Mountain (YM), Nevada

Three-dimensional two-phase mass transport model for direct methanol fuel cells

International Nuclear Information System (INIS)

Yang, W.W.; Zhao, T.S.; Xu, C.

2007-01-01

A three-dimensional (3D) steady-state model for liquid feed direct methanol fuel cells (DMFC) is presented in this paper. This 3D mass transport model is formed by integrating five sub-models, including a modified drift-flux model for the anode flow field, a two-phase mass transport model for the porous anode, a single-phase model for the polymer electrolyte membrane, a two-phase mass transport model for the porous cathode, and a homogeneous mist-flow model for the cathode flow field. The two-phase mass transport models take account the effect of non-equilibrium evaporation/ condensation at the gas-liquid interface. A 3D computer code is then developed based on the integrated model. After being validated against the experimental data reported in the literature, the code was used to investigate numerically transport behaviors at the DMFC anode and their effects on cell performance

Dynamic model of ion and water transport in ionic polymer-metal composites

Directory of Open Access Journals (Sweden)

Zicai Zhu

2011-12-01

Full Text Available In the process of electro-mechanical transduction of ionic polymer-metal composites (IPMCs, the transport of ion and water molecule plays an important role. In this paper, the theoretical transport models of IPMCs are critically reviewed, with particular emphasis on the recent developments in the latest decade. The models can be divided into three classes, thermodynamics of irreversible process model, frictional model and Nernst-Planck (NP equation model. To some extent the three models can be transformed into each other, but their differences are also obvious arising from the various mechanisms that considered in different models. The transport of ion and water molecule in IPMCs is compared with that in membrane electrode assembly and electrodialysis membrane to identify and clarify the fundamental transport mechanisms in IPMCs. And an improved transport model is proposed and simplified for numerical analysis. The model considers the convection effect rather than the diffusion as the major transport mechanism, and both the self-diffusion and the electroosmosis drag are accounted for in the water flux equation.

Sediment and toxic contaminant transport modeling in coastal waters

International Nuclear Information System (INIS)

Onishi, Y.; Mayer, D.W.; Argo, R.S.

1982-02-01

A hydrodynamic model, CAFE-I, a wave refraction model, LO3D, and a sediment and contaminant transport model, FETRA, were selected as tools for evaluating exposure levels of radionuclides, heavy metals, and other toxic chemicals in coastal waters. Prior to the application of these models to the Irish Sea and other coastal waters, the finite element model, FETRA, was tested to demonstrate its ability to simulate sediment and contaminant interactions (e.g., adsorption and desorption), and the mechanisms governing the transport, deposition, and resuspension of contaminated sediments

Modelling the transport system in China and evaluating the current strategies towards the sustainable transport development

International Nuclear Information System (INIS)

Liu, Wen; Lund, Henrik; Mathiesen, Brian Vad

2013-01-01

Transport is one of the most challenge sectors when addressing energy security and climate change due to its high reliance on oil products and lack of the alternative fuels. This paper explores the ability of three transport strategies to contribute to the development of a sustainable transport in China. With this purpose in mind, a Chinese transport model has been created and three current transport strategies which are high speed railway (HSR), urban rail transit (URT) and electric vehicle (EV) were evaluated together with a reference transport system in 2020. As conservative results, 13% of the energy saving and 12% of the CO 2 emission reduction can be attained by accomplishing three strategies compared with the reference transport system. However, the energy demand of transport in 2020 with the implementation of three strategies will be about 1.7 times as much as today. The three strategies show the potential of drawing the transport demand to the more energy efficient vehicles; however, more initiatives are needed if the sustainable transport is the long term objective, such as the solutions to stabilise the private vehicle demands, to continuously improve the vehicle efficiency and to boost the alternative fuels produced from the renewable energy sources. - Highlights: • A Chinese transport model was created and three transport strategies were evaluated • Transport is the biggest driver of the oil demand in China not the industry • The energy demand of transport in 2020 will be twice as much as today • Strategies contribute 13% energy saving and 12% CO 2 emission reduction • More initiatives are needed if a sustainable transport is the long-term objective

Radon transport in fractured soil. Laboratory experiments and modelling

International Nuclear Information System (INIS)

Hoff, A.

1997-10-01

Radon (Rn-222) transport in fractured soil has been investigated by laboratory experiments and by modelling. Radon transport experiments have been performed with two sand columns (homogeneous and inhomogeneous) and one undisturbed clayey till column containing a net of preferential flow paths (root holes). A numerical model (the finite-element model FRACTRAN) and an analytic model (a pinhole model) have been applied in simulations if soil gas and radon transport in fractured soil. Experiments and model calculations are included in a discussion of radon entry rates into houses placed on fractured soil. The main conclusion is, that fractures does not in general alter transport of internally generated radon out of soil, when the pressure and flow conditions in the soil is comparable to the conditions prevailing under a house. This indicates the important result, that fractures in soil have no impact on radon entry into a house beyond that of an increased gas permeability, but a more thorough investigation of this subject is needed. Only in the case where the soil is exposed to large pressure gradients, relative to gradients induced by a house, may it be possible to observe effects of radon exchange between fractures and matrix. (au) 52 tabs., 60 ill., 5 refs

Radon transport in fractured soil. Laboratory experiments and modelling

Energy Technology Data Exchange (ETDEWEB)

Hoff, A

1997-10-01

Radon (Rn-222) transport in fractured soil has been investigated by laboratory experiments and by modelling. Radon transport experiments have been performed with two sand columns (homogeneous and inhomogeneous) and one undisturbed clayey till column containing a net of preferential flow paths (root holes). A numerical model (the finite-element model FRACTRAN) and an analytic model (a pinhole model) have been applied in simulations if soil gas and radon transport in fractured soil. Experiments and model calculations are included in a discussion of radon entry rates into houses placed on fractured soil. The main conclusion is, that fractures does not in general alter transport of internally generated radon out of soil, when the pressure and flow conditions in the soil is comparable to the conditions prevailing under a house. This indicates the important result, that fractures in soil have no impact on radon entry into a house beyond that of an increased gas permeability, but a more thorough investigation of this subject is needed. Only in the case where the soil is exposed to large pressure gradients, relative to gradients induced by a house, may it be possible to observe effects of radon exchange between fractures and matrix. (au) 52 tabs., 60 ill., 5 refs.

Hydrogeochemical characteristics and assessment of water quality in the Al-Saad Lake, Abha Saudi Arabia

Science.gov (United States)

Mallick, Javed

2017-10-01

Hydrogeochemical characteristics and assessment of water quality investigations have been carried out at Abha, located in Saudi Arabia, where Al-Saad Lake represents a rare example of natural endorheic lake. The ecosystem within and around the Al-Saad Lake including catchment area is of great social, cultural, aesthetic, environmental and economic values to Abha. Sampling and experiments of lake water has been carried out with the aim of characterizing the main physico-chemical parameters, such as DO, EC, TDS, Mg2+, Ca2+, Na+, K+, SO4 2-, Cl-, HCO3, NO3 - and F- concentration. The ordinary kriging (OK) method was used to produce the spatial patterns of water quality. The Result of DO (mean 5.38 mg/L) trend in Al-Saad Lake is not very encouraging as majority of the lake area is under DO stress or marginally above it. So, proper management strategies are needed to be formulated to protect flora and fauna of the lake. Furthermore, the chemical analysis results show the abundance of the major cations in the order Mg2+ > Ca2+ > Na+ > K+ whereas the abundance of anions are in the order SO4 2- > Cl- > HCO3 > NO3 - > F-. The result obtained in this investigation inferred that the cations in water i.e. sodium and iron are within the permissible limits but magnesium and potassium have exceeded the permissible limit. Whereas anions such as nitrate and fluoride are within the permissible range but chloride and sulphate have exceeded the permissible limits. The concentration of cation, magnesium (Mg) and potassium (K) in the lake water has exceeded the desirable range (30, 10 mg/L, respectively). This may be due to weathering and transported from rocks and particularly from sulphate deposits such as gypsum and anhydride and subsequently ends up in water. The concentration of anion, Sulphate (SO4) and chloride are above the desirable limit. The major source of bicarbonate are the carbonate rocks containing calcite (CaCO3) and dolomite (CaMg (CO3)2), Calcium (Ca) and Magnesium

Modeling spin magnetization transport in a spatially varying magnetic field

Science.gov (United States)

Picone, Rico A. R.; Garbini, Joseph L.; Sidles, John A.

2015-01-01

We present a framework for modeling the transport of any number of globally conserved quantities in any spatial configuration and apply it to obtain a model of magnetization transport for spin-systems that is valid in new regimes (including high-polarization). The framework allows an entropy function to define a model that explicitly respects the laws of thermodynamics. Three facets of the model are explored. First, it is expressed as nonlinear partial differential equations that are valid for the new regime of high dipole-energy and polarization. Second, the nonlinear model is explored in the limit of low dipole-energy (semi-linear), from which is derived a physical parameter characterizing separative magnetization transport (SMT). It is shown that the necessary and sufficient condition for SMT to occur is that the parameter is spatially inhomogeneous. Third, the high spin-temperature (linear) limit is shown to be equivalent to the model of nuclear spin transport of Genack and Redfield (1975) [1]. Differences among the three forms of the model are illustrated by numerical solution with parameters corresponding to a magnetic resonance force microscopy (MRFM) experiment (Degen et al., 2009 [2]; Kuehn et al., 2008 [3]; Sidles et al., 2003 [4]; Dougherty et al., 2000 [5]). A family of analytic, steady-state solutions to the nonlinear equation is derived and shown to be the spin-temperature analog of the Langevin paramagnetic equation and Curie's law. Finally, we analyze the separative quality of magnetization transport, and a steady-state solution for the magnetization is shown to be compatible with Fenske's separative mass transport equation (Fenske, 1932 [6]).

Numerical modelling of solute transport at Forsmark with MIKE SHE. Site descriptive modelling SDM-Site Forsmark

Energy Technology Data Exchange (ETDEWEB)

Gustafsson, Lars-Goeran; Sassner, Mona (DHI Sverige AB, Stockholm (Sweden)); Bosson, Emma (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden))

2008-12-15

The Swedish Nuclear Fuel and Waste Management Company (SKB) is performing site investigations at two different locations in Sweden, referred to as the Forsmark and Laxemar areas, with the objective of siting a final repository for high-level radioactive waste. Data from the site investigations are used in a variety of modelling activities. This report presents model development and results of numerical transport modelling based on the numerical flow modelling of surface water and near-surface groundwater at the Forsmark site. The numerical modelling was performed using the modelling tool MIKE SHE and is based on the site data and conceptual model of the Forsmark areas. This report presents solute transport applications based on both particle tracking simulations and advection-dispersion calculations. The MIKE SHE model is the basis for the transport modelling presented in this report. Simulation cases relevant for the transport from a deep geological repository have been studied, but also the pattern of near surface recharge and discharge areas. When the main part of the modelling work presented in this report was carried out, the flow modelling of the Forsmark site was not finalised. Thus, the focus of this work is to describe the sensitivity to different transport parameters, and not to point out specific areas as discharge areas from a future repository (this is to be done later, within the framework of the safety assessment). In the last chapter, however, results based on simulations with the re-calibrated MIKE SHE flow model are presented. The results from the MIKE SHE water movement calculations were used by cycling the calculated transient flow field for a selected one-year period as many times as needed to achieve the desired simulation period. The solute source was located either in the bedrock or on top of the model. In total, 15 different transport simulation cases were studied. Five of the simulations were particle tracking simulations, whereas the rest

A self-organized criticality model for plasma transport

International Nuclear Information System (INIS)

Carreras, B.A.; Newman, D.; Lynch, V.E.

1996-01-01

Many models of natural phenomena manifest the basic hypothesis of self-organized criticality (SOC). The SOC concept brings together the self-similarity on space and time scales that is common to many of these phenomena. The application of the SOC modelling concept to the plasma dynamics near marginal stability opens new possibilities of understanding issues such as Bohm scaling, profile consistency, broad band fluctuation spectra with universal characteristics and fast time scales. A model realization of self-organized criticality for plasma transport in a magnetic confinement device is presented. The model is based on subcritical resistive pressure-gradient-driven turbulence. Three-dimensional nonlinear calculations based on this model show the existence of transport under subcritical conditions. This model that includes fluctuation dynamics leads to results very similar to the running sandpile paradigm

Evaluate transport processes in MERRA driven chemical transport models using updated 222Rn emission inventories and global observations

Science.gov (United States)

Zhang, B.; Liu, H.; Crawford, J. H.; Fairlie, T. D.; Chen, G.; Chambers, S. D.; Kang, C. H.; Williams, A. G.; Zhang, K.; Considine, D. B.; Payer Sulprizio, M.; Yantosca, R.

2015-12-01

Convective and synoptic processes play a major role in determining the transport and distribution of trace gases and aerosols in the troposphere. The representation of these processes in global models (at ~100-1000 km horizontal resolution) is challenging, because convection is a sub-grid process and needs to be parameterized, while synoptic processes are close to the grid scale. Depending on the parameterization schemes used in climate models, the role of convection in transporting trace gases and aerosols may vary from model to model. 222Rn is a chemically inert and radioactive gas constantly emitted from soil and has a half-life (3.8 days) comparable to synoptic timescale, which makes it an effective tracer for convective and synoptic transport. In this study, we evaluate the convective and synoptic transport in two chemical transport models (GMI and GEOS-Chem), both driven by the NASA's MERRA reanalysis. Considering the uncertainties in 222Rn emissions, we incorporate two more recent scenarios with regionally varying 222Rn emissions into GEOS-Chem/MERRA and compare the simulation results with those using the relatively uniform 222Rn emissions in the standard model. We evaluate the global distribution and seasonality of 222Rn concentrations simulated by the two models against an extended collection of 222Rn observations from 1970s to 2010s. The intercomparison will improve our understanding of the spatial variability in global 222Rn emissions, including the suspected excessive 222Rn emissions in East Asia, and provide useful feedbacks on 222Rn emission models. We will assess 222Rn vertical distributions at different latitudes in the models using observations at surface sites and in the upper troposphere and lower stratosphere. Results will be compared with previous models driven by other meteorological fields (e.g., fvGCM and GEOS4). Since the decay of 222Rn is the source of 210Pb, a useful radionuclide tracer attached to submicron aerosols, improved

Improving the theoretical foundations of the multi-mode transport model

International Nuclear Information System (INIS)

Bateman, G.; Kritz, A.H.; Redd, A.J.; Erba, M.; Rewoldt, G.; Weiland, J.; Strand, P.; Kinsey, J.E.; Scott, B.

1999-01-01

A new version of the Multi-Mode transport model, designated MMM98, is being developed with improved theoretical foundations, in an ongoing effort to predict the temperature and density profiles in tokamaks. For transport near the edge of the plasma, MMM98 uses a new model based on 3-D nonlinear simulations of drift Alfven mode turbulence. Flow shear stabilization effects have been added to the Weiland model for Ion Temperature Gradient and Trapped Electron Modes, which usually dominates in most of the plasma core. For transport near the magnetic axis at high beta, a new kinetic ballooning mode model has been constructed based on FULL stability code computations. (author)

Improving the theoretical foundations of the multi-mode transport model

International Nuclear Information System (INIS)

Bateman, G.; Kritz, A.H.; Redd, A.J.; Erba, M.; Rewoldt, G.; Weiland, J.; Strand, P.; Kinsey, J.E.; Scott, B.

2001-01-01

A new version of the Multi-Mode transport model, designated MMM98, is being developed with improved theoretical foundations, in an ongoing effort to predict the temperature and density profiles in tokamaks. For transport near the edge of the plasma, MMM98 uses a new model based on 3-D nonlinear simulations of drift Alfven mode turbulence. Flow shear stabilization effects have been added to the Weiland model for Ion Temperature Gradient and Trapped Electron Modes, which usually dominates in most of the plasma core. For transport near the magnetic axis at high beta, a new kinetic ballooning mode model has been constructed based on FULL stability code computations. (author)

Data-based mathematical modeling of vectorial transport across double-transfected polarized cells.

Science.gov (United States)

Bartholomé, Kilian; Rius, Maria; Letschert, Katrin; Keller, Daniela; Timmer, Jens; Keppler, Dietrich

2007-09-01

Vectorial transport of endogenous small molecules, toxins, and drugs across polarized epithelial cells contributes to their half-life in the organism and to detoxification. To study vectorial transport in a quantitative manner, an in vitro model was used that includes polarized MDCKII cells stably expressing the recombinant human uptake transporter OATP1B3 in their basolateral membrane and the recombinant ATP-driven efflux pump ABCC2 in their apical membrane. These double-transfected cells enabled mathematical modeling of the vectorial transport of the anionic prototype substance bromosulfophthalein (BSP) that has frequently been used to examine hepatobiliary transport. Time-dependent analyses of (3)H-labeled BSP in the basolateral, intracellular, and apical compartments of cells cultured on filter membranes and efflux experiments in cells preloaded with BSP were performed. A mathematical model was fitted to the experimental data. Data-based modeling was optimized by including endogenous transport processes in addition to the recombinant transport proteins. The predominant contributions to the overall vectorial transport of BSP were mediated by OATP1B3 (44%) and ABCC2 (28%). Model comparison predicted a previously unrecognized endogenous basolateral efflux process as a negative contribution to total vectorial transport, amounting to 19%, which is in line with the detection of the basolateral efflux pump Abcc4 in MDCKII cells. Rate-determining steps in the vectorial transport were identified by calculating control coefficients. Data-based mathematical modeling of vectorial transport of BSP as a model substance resulted in a quantitative description of this process and its components. The same systems biology approach may be applied to other cellular systems and to different substances.

Use of artificial neural networks for transport energy demand modeling

International Nuclear Information System (INIS)

Murat, Yetis Sazi; Ceylan, Halim

2006-01-01

The paper illustrates an artificial neural network (ANN) approach based on supervised neural networks for the transport energy demand forecasting using socio-economic and transport related indicators. The ANN transport energy demand model is developed. The actual forecast is obtained using a feed forward neural network, trained with back propagation algorithm. In order to investigate the influence of socio-economic indicators on the transport energy demand, the ANN is analyzed based on gross national product (GNP), population and the total annual average veh-km along with historical energy data available from 1970 to 2001. Comparing model predictions with energy data in testing period performs the model validation. The projections are made with two scenarios. It is obtained that the ANN reflects the fluctuation in historical data for both dependent and independent variables. The results obtained bear out the suitability of the adopted methodology for the transport energy-forecasting problem

Hydrogeological and Hydrogeochemical Modelling of the Alicun de las Torres Termal System (Province of Granada). Isotope Hydrochemistry and Gases in Groundwaters; Modelizacion Hidrogeologica e Hidrogeoquimica del Sistema Termal de Alicun de Las Torres (Provincia de Granada). Hidroquimica Isotopica y Gases en Aguas

Energy Technology Data Exchange (ETDEWEB)

Prado Perez, A. J.; Delgado, A.; Crespo, M. T.; Martin, A.; Vaselli, O.; Perez del Villar, L.

2010-11-17

In the framework of a Singular Strategic Project entitled: {sup A}dvanced Technologies of Carbon, Capture and Storage (CCS){sup ,} supported by the MICINN (Spain) and the FEDER founds (EU), specifically in the Carbon Storage Task, a comprehensive study on the CO{sub 2} leakage as DIC (Dissolved Inorganic Carbon) in the Alicun de Las Torres (Prov. of Granada) natural analogue thermal system was envisaged. This analogous system is characterised by the presence of a very important travertine formation, which can be considered as a permanent and stable sink for CO{sub 2}. In order to explain the formation of these travertine mass an hydrogeological and hydrogeochemical model of the area has been established by using the hydrochemical data, the stable and radioactive isotope characteristics, the dissolved inorganic carbon, as well as the chemical and isotopic composition of the free and dissolved gases of the above mentioned Thermal System. (Author) 11 refs.

A one-dimensional plasma and impurity transport model for reversed field pinches

International Nuclear Information System (INIS)

Veerasingam, R.

1991-11-01

In this thesis a one-dimensional (1-D) plasma and impurity transport model is developed to address issues related to impurity behavior in Reversed Field Pinch (RFP) fusion plasmas. A coronal non-equilibrium model is used for impurities. The impurity model is incorporated into an existing one dimensional plasma transport model creating a multi-species plasma transport model which treats the plasma and impurity evolution self-consistently. Neutral deuterium particles are treated using a one-dimensional (slab) model of neutral transport. The resulting mode, RFPBI, is then applied to existing RFP devices such as ZT-40M and MST, and also to examine steady state behavior of ZTH based on the design parameters. A parallel algorithm for the impurity transport equations is implemented and tested to determine speedup and efficiency

An intermodal transportation geospatial network modeling for containerized soybean shipping

Directory of Open Access Journals (Sweden)

Xiang Liu

2017-06-01

Full Text Available Containerized shipping is a growing market for agricultural exports, particularly soybeans. In order to understand the optimal strategies for improving the United States’ economic competitiveness in this emerging market, this research develops an intermodal transportation network modeling framework, focusing on U.S. soybean container shipments. Built upon detailed modal cost analyses, a Geospatial Intermodal Freight Transportation (GIFT model has been developed to understand the optimal network design for U.S. soybean exports. Based on market demand and domestic supply figures, the model is able to determine which domestically produced soybeans should go to which foreign markets, and by which transport modes. This research and its continual studies, will provide insights into future policies and practices that can improve the transportation efficiency of soybean logistics.

Distribution of pollutant transport at landfill site, Taiping, Perak, Malaysia

International Nuclear Information System (INIS)

Roslanzairi Mostapa; Kamarudin Samuding; Mohd Tadza Abdul Rahman; Mohd Rifaie Mohd Murtadza; Ismail Abustan; Mohd Suhaimi Hamzah; Shamsiah Abdul Rahman; Nazaratul Ashifa Abdullah Salim

2004-01-01

This paper describes the preliminary report on the distribution of pollutant transport at Taiping municipal waste disposal site, Perak. This study involved the sampling of surface water and groundwater at various locations within the area. The hydrogeochemical method was used to determine the concentration of heavy metals i.e. Cr, Mn, Zn, As, Cd, Pb, and Fe. In-situ conductivity measurement was taken as a screening method for preliminary analysis purpose. Most of the groundwater at several boreholes contains high concentration of heavy metals. This indicates that some of the groundwater has been contaminated. The presence of heavy metals concentration in the surface water (river and pond) seems to be relatively low compared to maximum contaminant level (MCL) allowed in drinking water. Heavy metals that show significant changes and exceed the MCL are Mn, Zn, Pb and Fe. The conductivity value for the first sampling at various locations on December 2003 ranges from 60 - 12830 μS/cm and the these values were relatively increased on the second sampling in February 2004 which ranges from 155 - 13760 μS/cm. The sampling will be continued to obtain several series of complete data so that a conclusive evaluation of pollutant transport can be made. (Author)

How uncertainty in socio-economic variables affects large-scale transport model forecasts

DEFF Research Database (Denmark)

Manzo, Stefano; Nielsen, Otto Anker; Prato, Carlo Giacomo

2015-01-01

A strategic task assigned to large-scale transport models is to forecast the demand for transport over long periods of time to assess transport projects. However, by modelling complex systems transport models have an inherent uncertainty which increases over time. As a consequence, the longer...... the period forecasted the less reliable is the forecasted model output. Describing uncertainty propagation patterns over time is therefore important in order to provide complete information to the decision makers. Among the existing literature only few studies analyze uncertainty propagation patterns over...

Test of 1-D transport models, and their predictions for ITER

International Nuclear Information System (INIS)

Mikkelsen, D.; Bateman, G.; Boucher, D.

2001-01-01

A number of proposed tokamak thermal transport models are tested by comparing their predictions with measurements from several tokamaks. The necessary data have been provided for a total of 75 discharges from C-mod, DIII-D, JET, JT-60U, T10, and TFTR. A standard prediction methodology has been developed, and three codes have been benchmarked; these 'standard' codes have been relied on for testing most of the transport models. While a wide range of physical transport processes has been tested, no single model has emerged as clearly superior to all competitors for simulating H-mode discharges. In order to winnow the field, further tests of the effect of sheared flows and of the 'stiffness' of transport are planned. Several of the models have been used to predict ITER performance, with widely varying results. With some transport models ITER's predicted fusion power depends strongly on the 'pedestal' temperature, but ∼ 1GW (Q=10) is predicted for most models if the pedestal temperature is at least 4 keV. (author)

Tests of 1-D transport models, and their predictions for ITER

International Nuclear Information System (INIS)

Mikkelsen, D.R.; Bateman, G.; Boucher, D.

1999-01-01

A number of proposed tokamak thermal transport models are tested by comparing their predictions with measurements from several tokamaks. The necessary data have been provided for a total of 75 discharges from C-mod, DIII-D, JET, JT-60U, T10, and TFTR. A standard prediction methodology has been developed, and three codes have been benchmarked; these 'standard' codes have been relied on for testing most of the transport models. While a wide range of physical transport processes has been tested, no single model has emerged as clearly superior to all competitors for simulating H-mode discharges. In order to winnow the field, further tests of the effect of sheared flows and of the 'stiffness' of transport are planned. Several of the models have been used to predict ITER performance, with widely varying results. With some transport models ITER's predicted fusion power depends strongly on the 'pedestal' temperature, but ∼ 1GW (Q=10) is predicted for most models if the pedestal temperature is at least 4 keV. (author)

Models in Planning Urban Public Passenger Transport

Directory of Open Access Journals (Sweden)

Gordana Štefančić

2007-07-01

Full Text Available The solving of complex problems in public transport requiresthe usage of models that are based on the estimate of demandin planning the transport routes. The intention is to predictwhat is going to happen in the future, if the proposed solutionsare implemented. In the majority of cases, the publictransport system is formed as a network and stored in the computermemory in order to start the evaluation process by specifYingthe number of trip origins and destinations in each zone.The trip distribution model which is used to calculate the numberof trips between each pair in the zone is based on the overalltravel frictions from zone to zone.

Modeling sediment transport with an integrated view of the biofilm effects

Science.gov (United States)

Fang, H. W.; Lai, H. J.; Cheng, W.; Huang, L.; He, G. J.

2017-09-01

Most natural sediment is invariably covered by biofilms in reservoirs and lakes, which have significant influence on bed form dynamics and sediment transport, and also play a crucial role in natural river evolution, pollutant transport, and habitat changes. However, most models for sediment transport are based on experiments using clean sediments without biological materials. In this study, a three-dimensional mathematical model of hydrodynamics and sediment transport is presented with a comprehensive consideration of the biofilm effects. The changes of the bed resistance mainly due to the different bed form dynamics of the biofilm-coated sediment (biosediment), which affect the hydrodynamic characteristics, are considered. Moreover, the variations of parameters related to sediment transport after the biofilm growth are integrated, including the significant changes of the incipient velocity, settling velocity, reference concentration, and equilibrium bed load transport rate. The proposed model is applied to evaluate the effects of biofilms on the hydrodynamic characteristics and sediment transport in laboratory experiments. Results indicate that the mean velocity increases after the biofilm growth, and the turbulence intensity near the river bed decreases under the same flow condition. Meanwhile, biofilm inhibits sediment from moving independently. Thus, the moderate erosion is observed for biosediment resulting in smaller suspended sediment concentrations. The proposed model can reasonably reflect these sediment transport characteristics with biofilms, and the approach to integration of the biological impact could also be used in other modeling of sediment transport, which can be further applied to provide references for the integrated management of natural aqueous systems.

Time-dependent Perpendicular Transport of Energetic Particles for Different Turbulence Configurations and Parallel Transport Models

Energy Technology Data Exchange (ETDEWEB)

Lasuik, J.; Shalchi, A., E-mail: andreasm4@yahoo.com [Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB R3T 2N2 (Canada)

2017-09-20

Recently, a new theory for the transport of energetic particles across a mean magnetic field was presented. Compared to other nonlinear theories the new approach has the advantage that it provides a full time-dependent description of the transport. Furthermore, a diffusion approximation is no longer part of that theory. The purpose of this paper is to combine this new approach with a time-dependent model for parallel transport and different turbulence configurations in order to explore the parameter regimes for which we get ballistic transport, compound subdiffusion, and normal Markovian diffusion.

Interactive 4D Visualization of Sediment Transport Models

Science.gov (United States)

Butkiewicz, T.; Englert, C. M.

2013-12-01

Coastal sediment transport models simulate the effects that waves, currents, and tides have on near-shore bathymetry and features such as beaches and barrier islands. Understanding these dynamic processes is integral to the study of coastline stability, beach erosion, and environmental contamination. Furthermore, analyzing the results of these simulations is a critical task in the design, placement, and engineering of coastal structures such as seawalls, jetties, support pilings for wind turbines, etc. Despite the importance of these models, there is a lack of available visualization software that allows users to explore and perform analysis on these datasets in an intuitive and effective manner. Existing visualization interfaces for these datasets often present only one variable at a time, using two dimensional plan or cross-sectional views. These visual restrictions limit the ability to observe the contents in the proper overall context, both in spatial and multi-dimensional terms. To improve upon these limitations, we use 3D rendering and particle system based illustration techniques to show water column/flow data across all depths simultaneously. We can also encode multiple variables across different perceptual channels (color, texture, motion, etc.) to enrich surfaces with multi-dimensional information. Interactive tools are provided, which can be used to explore the dataset and find regions-of-interest for further investigation. Our visualization package provides an intuitive 4D (3D, time-varying) visualization of sediment transport model output. In addition, we are also integrating real world observations with the simulated data to support analysis of the impact from major sediment transport events. In particular, we have been focusing on the effects of Superstorm Sandy on the Redbird Artificial Reef Site, offshore of Delaware Bay. Based on our pre- and post-storm high-resolution sonar surveys, there has significant scour and bedform migration around the

Coupled models in porous media: reactive transport and fractures

International Nuclear Information System (INIS)

Amir, L.

2008-12-01

This thesis deals with numerical simulation of coupled models for flow and transport in porous media. We present a new method for coupling chemical reactions and transport by using a Newton-Krylov method, and we also present a model of flow in fractured media, based on a domain decomposition method that takes into account the case of intersecting fractures. This study is composed of three parts: the first part contains an analysis, and implementation, of various numerical methods for discretizing advection-diffusion problems, in particular by using operator splitting methods. The second part is concerned with a fully coupled method for modeling transport and chemistry problems. The coupled transport-chemistry model is described, after discretization in time, by a system of nonlinear equations. The size of the system, namely the number of grid points times the number a chemical species, precludes a direct solution of the linear system. To alleviate this difficulty, we solve the system by a Newton-Krylov method, so as to avoid forming and factoring the Jacobian matrix. In the last part, we present a model of flow in 3D for intersecting fractures, by using a domain decomposition method. The fractures are treated as interfaces between sub-domains. We show existence and uniqueness of the solution, and we validate the model by numerical tests. (author)

Transport modelling including radial electric field and plasma rotation

International Nuclear Information System (INIS)

Fukuyama, A.; Fuji, Y.; Itoh, S.-I.

1994-01-01

Using a simple turbulent transport model with a constant diffusion coefficient and a fixed temperature profile, the density profile in a steady state and the transient behaviour during the co and counter neutral beam injection are studied. More consistent analysis has been initiated with a turbulent transport model based on the current diffusive high-n ballooning mode. The enhancement of the radial electric field due to ion orbit losses and the reduction of the transport due to the poloidal rotation shear are demonstrated. The preliminary calculation indicates a sensitive temperature dependence of the density profile. (author)

Application of transport demand modeling in pollution estimation of a street network

Directory of Open Access Journals (Sweden)

Jović Jadranka J.

2009-01-01

Full Text Available The importance of transportation modeling, especially personal car flow modeling, is well recognized in transportation planning. Modern software tools give the possibility of generating many development scenarios of transport system, which can be tested quickly. Transportation models represent a good (and necessary basis in the procedure of environmental traffic impacts and energy emission estimation. Research in this paper deals with the possibility of using transportation modeling as a tool for estimation of some air pollution and global warming indicators on street network, produced by personal cars with internal combustion engines. These indicators could be the basis for defining planning and management solutions for transport system with respect to their environmental impacts. All the analyses are based on several years of research experience in Belgrade. According to the emissions of gases from the model, the values of other green house gases can be estimated using the known relations between the pollutants. There is a possibility that all these data can be used to calculate the transportation systems impact on temperature increase in urban areas.

Collection and preparation of water samples for hydrogeochemical reconnaissance

International Nuclear Information System (INIS)

Baucom, E.I.; Ferguson, R.B.; Wallace, R.M.

1977-01-01

A method based on ion exchange and neutron activation analysis (NAA) was developed and field-tested to determine uranium over the range 0.02 to 10,000 ppb in natural water using a single procedure. Water samples are filtered in the field using a specially-designed one-liter filter apparatus pressurized to 40 psig with an inert gas. The filtered water is treated with a high purity, mixed cation-anion resin in the hydronium-hydroxide form. All ions are removed from solution under the strong driving force of the neutralization reaction. Anionic, cationic, and natural complexes of uranium can be concentrated with this method. Field tests showed greater than 95 percent recovery of 13 elements analyzed (including greater than 99 percent recovery of uranium) and greater than or equal to 90 percent recovery of 4 other elements. Uranium collected on the resin was quantitatively determined by NAA. Coefficient of variation for sampling plus analysis was less than 20 percent for samples containing more than 0.1 ppb uranium. Advantages of this method include: (1) wide dynamic range, (2) low detection limit for uranium (0.02 ppb), (3) high precision and accuracy, (4) relatively low cost, (5) high-yield recovery from low-level aqueous samples without risk of loss to containers, (6) decreased risk of significant sample contamination compared with other low-level methods, (7) production of stable samples suitable for retrievable storage, and(8) concentration of other ions that can be determined by NAA. This paper presents (1) background regarding development of procedures for sample collection and preparation, (2) results of development programs, (3) description of equipment and field procedures, and (4) preliminary conclusions regarding use of this technology for hydrogeochemical reconnaissance for uranium

Multi-scale modelling and numerical simulation of electronic kinetic transport

International Nuclear Information System (INIS)

Duclous, R.

2009-11-01

This research thesis which is at the interface between numerical analysis, plasma physics and applied mathematics, deals with the kinetic modelling and numerical simulations of the electron energy transport and deposition in laser-produced plasmas, having in view the processes of fuel assembly to temperature and density conditions necessary to ignite fusion reactions. After a brief review of the processes at play in the collisional kinetic theory of plasmas, with a focus on basic models and methods to implement, couple and validate them, the author focuses on the collective aspect related to the free-streaming electron transport equation in the non-relativistic limit as well as in the relativistic regime. He discusses the numerical development and analysis of the scheme for the Vlasov-Maxwell system, and the selection of a validation procedure and numerical tests. Then, he investigates more specific aspects of the collective transport: the multi-specie transport, submitted to phase-space discontinuities. Dealing with the multi-scale physics of electron transport with collision source terms, he validates the accuracy of a fast Monte Carlo multi-grid solver for the Fokker-Planck-Landau electron-electron collision operator. He reports realistic simulations for the kinetic electron transport in the frame of the shock ignition scheme, the development and validation of a reduced electron transport angular model. He finally explores the relative importance of the processes involving electron-electron collisions at high energy by means a multi-scale reduced model with relativistic Boltzmann terms

Simulation of internal transport barriers by means of the canonical profile transport model

International Nuclear Information System (INIS)

Dnestrovskij, Yu. N.; Cherkasov, S. V.; Dnestrovskij, A. Yu.; Lysenko, S. E.; Walsh, M. J.

2006-01-01

Models with critical gradients are widely used to describe energy balance in L-mode discharges. The so-called first critical gradient can be found from the canonical temperature profile. Here, it is suggested that discharge regimes with transport barriers can be described based on the idea of the second critical gradient. If, in a certain plasma region, the pressure gradient exceeds the second critical gradient, then the plasma bifurcates into a new state and a transport barrier forms in this region. This idea was implemented in a modified canonical profile transport model that makes it possible to describe the energy and particle balance in tokamak plasmas with arbitrary cross sections and aspect ratios. The magnitude of the second critical gradient was chosen by comparing the results calculated for several tokamak discharges with the experimental data. It is found that the second critical gradient is related to the magnetic shear s. The criterion of the transport barrier formation has the form (a 2 /r)d/drln(p/p c ) > z 0 (r), where r is the radial coordinate, a is the plasma minor radius, p is the plasma pressure, p c is the canonical pressure profile, and the dimensionless function z O (r) = C O + C 1 s (with C 0i ∼1, C 0e ∼3, and C 1i,e ∼2) describes the difference between the first and second critical gradients. Simulations show that this criterion is close to that obtained experimentally in JET. The model constructed here is used to simulate internal transport barriers in the JET, TFTR, DIII-D, and MAST tokamaks. The possible dependence of the second critical gradient on the plasma parameters is discussed

Dynamic modeling of interfacial structures via interfacial area transport equation

International Nuclear Information System (INIS)

Seungjin, Kim; Mamoru, Ishii

2005-01-01

The interfacial area transport equation dynamically models the two-phase flow regime transitions and predicts continuous change of the interfacial area concentration along the flow field. Hence, when employed in the numerical thermal-hydraulic system analysis codes, it eliminates artificial bifurcations stemming from the use of the static flow regime transition criteria. Accounting for the substantial differences in the transport phenomena of various sizes of bubbles, the two-group interfacial area transport equations have been developed. The group 1 equation describes the transport of small-dispersed bubbles that are either distorted or spherical in shapes, and the group 2 equation describes the transport of large cap, slug or churn-turbulent bubbles. The source and sink terms in the right-hand-side of the transport equations have been established by mechanistically modeling the creation and destruction of bubbles due to major bubble interaction mechanisms. In the present paper, the interfacial area transport equations currently available are reviewed to address the feasibility and reliability of the model along with extensive experimental results. These include the data from adiabatic upward air-water two-phase flow in round tubes of various sizes, from a rectangular duct, and from adiabatic co-current downward air-water two-phase flow in round pipes of two sizes. (authors)

Recommended direct simulation Monte Carlo collision model parameters for modeling ionized air transport processes

Energy Technology Data Exchange (ETDEWEB)

Swaminathan-Gopalan, Krishnan; Stephani, Kelly A., E-mail: ksteph@illinois.edu [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)

2016-02-15

A systematic approach for calibrating the direct simulation Monte Carlo (DSMC) collision model parameters to achieve consistency in the transport processes is presented. The DSMC collision cross section model parameters are calibrated for high temperature atmospheric conditions by matching the collision integrals from DSMC against ab initio based collision integrals that are currently employed in the Langley Aerothermodynamic Upwind Relaxation Algorithm (LAURA) and Data Parallel Line Relaxation (DPLR) high temperature computational fluid dynamics solvers. The DSMC parameter values are computed for the widely used Variable Hard Sphere (VHS) and the Variable Soft Sphere (VSS) models using the collision-specific pairing approach. The recommended best-fit VHS/VSS parameter values are provided over a temperature range of 1000-20 000 K for a thirteen-species ionized air mixture. Use of the VSS model is necessary to achieve consistency in transport processes of ionized gases. The agreement of the VSS model transport properties with the transport properties as determined by the ab initio collision integral fits was found to be within 6% in the entire temperature range, regardless of the composition of the mixture. The recommended model parameter values can be readily applied to any gas mixture involving binary collisional interactions between the chemical species presented for the specified temperature range.

Numerical modelling of solute transport at Forsmark with MIKE SHE. Site descriptive modelling SDM-Site Forsmark

International Nuclear Information System (INIS)

Gustafsson, Lars-Goeran; Sassner, Mona; Bosson, Emma

2008-12-01

The Swedish Nuclear Fuel and Waste Management Company (SKB) is performing site investigations at two different locations in Sweden, referred to as the Forsmark and Laxemar areas, with the objective of siting a final repository for high-level radioactive waste. Data from the site investigations are used in a variety of modelling activities. This report presents model development and results of numerical transport modelling based on the numerical flow modelling of surface water and near-surface groundwater at the Forsmark site. The numerical modelling was performed using the modelling tool MIKE SHE and is based on the site data and conceptual model of the Forsmark areas. This report presents solute transport applications based on both particle tracking simulations and advection-dispersion calculations. The MIKE SHE model is the basis for the transport modelling presented in this report. Simulation cases relevant for the transport from a deep geological repository have been studied, but also the pattern of near surface recharge and discharge areas. When the main part of the modelling work presented in this report was carried out, the flow modelling of the Forsmark site was not finalised. Thus, the focus of this work is to describe the sensitivity to different transport parameters, and not to point out specific areas as discharge areas from a future repository (this is to be done later, within the framework of the safety assessment). In the last chapter, however, results based on simulations with the re-calibrated MIKE SHE flow model are presented. The results from the MIKE SHE water movement calculations were used by cycling the calculated transient flow field for a selected one-year period as many times as needed to achieve the desired simulation period. The solute source was located either in the bedrock or on top of the model. In total, 15 different transport simulation cases were studied. Five of the simulations were particle tracking simulations, whereas the rest

Unified computational model of transport in metal-insulating oxide-metal systems

Science.gov (United States)

Tierney, B. D.; Hjalmarson, H. P.; Jacobs-Gedrim, R. B.; Agarwal, Sapan; James, C. D.; Marinella, M. J.

2018-04-01

A unified physics-based model of electron transport in metal-insulator-metal (MIM) systems is presented. In this model, transport through metal-oxide interfaces occurs by electron tunneling between the metal electrodes and oxide defect states. Transport in the oxide bulk is dominated by hopping, modeled as a series of tunneling events that alter the electron occupancy of defect states. Electron transport in the oxide conduction band is treated by the drift-diffusion formalism and defect chemistry reactions link all the various transport mechanisms. It is shown that the current-limiting effect of the interface band offsets is a function of the defect vacancy concentration. These results provide insight into the underlying physical mechanisms of leakage currents in oxide-based capacitors and steady-state electron transport in resistive random access memory (ReRAM) MIM devices. Finally, an explanation of ReRAM bipolar switching behavior based on these results is proposed.

Surrogate model approach for improving the performance of reactive transport simulations

Science.gov (United States)

Jatnieks, Janis; De Lucia, Marco; Sips, Mike; Dransch, Doris

2016-04-01

Reactive transport models can serve a large number of important geoscientific applications involving underground resources in industry and scientific research. It is common for simulation of reactive transport to consist of at least two coupled simulation models. First is a hydrodynamics simulator that is responsible for simulating the flow of groundwaters and transport of solutes. Hydrodynamics simulators are well established technology and can be very efficient. When hydrodynamics simulations are performed without coupled geochemistry, their spatial geometries can span millions of elements even when running on desktop workstations. Second is a geochemical simulation model that is coupled to the hydrodynamics simulator. Geochemical simulation models are much more computationally costly. This is a problem that makes reactive transport simulations spanning millions of spatial elements very difficult to achieve. To address this problem we propose to replace the coupled geochemical simulation model with a surrogate model. A surrogate is a statistical model created to include only the necessary subset of simulator complexity for a particular scenario. To demonstrate the viability of such an approach we tested it on a popular reactive transport benchmark problem that involves 1D Calcite transport. This is a published benchmark problem (Kolditz, 2012) for simulation models and for this reason we use it to test the surrogate model approach. To do this we tried a number of statistical models available through the caret and DiceEval packages for R, to be used as surrogate models. These were trained on randomly sampled subset of the input-output data from the geochemical simulation model used in the original reactive transport simulation. For validation we use the surrogate model to predict the simulator output using the part of sampled input data that was not used for training the statistical model. For this scenario we find that the multivariate adaptive regression splines

Dynamic modeling of interfacial structures via interfacial area transport equation

International Nuclear Information System (INIS)

Seungjin, Kim; Mamoru, Ishii

2004-01-01

Full text of publication follows:In the current thermal-hydraulic system analysis codes using the two-fluid model, the empirical correlations that are based on the two-phase flow regimes and regime transition criteria are being employed as closure relations for the interfacial transfer terms. Due to its inherent shortcomings, however, such static correlations are inaccurate and present serious problems in the numerical analysis. In view of this, a new dynamic approach employing the interfacial area transport equation has been studied. The interfacial area transport equation dynamically models the two-phase flow regime transitions and predicts continuous change of the interfacial area concentration along the flow field. Hence, when employed in the thermal-hydraulic system analysis codes, it eliminates artificial bifurcations stemming from the use of the static flow regime transition criteria. Therefore, the interfacial area transport equation can make a leapfrog improvement in the current capability of the two-fluid model from both scientific and practical point of view. Accounting for the substantial differences in the transport phenomena of various sizes of bubbles, the two-group interfacial area transport equations have been developed. The group 1 equation describes the transport of small-dispersed bubbles that are either distorted or spherical in shapes, and the group 2 equation describes the transport of large cap, slug or churn-turbulent bubbles. The source and sink terms in the right hand-side of the transport equations have been established by mechanistically modeling the creation and destruction of bubbles due to major bubble interaction mechanisms. The coalescence mechanisms include the random collision driven by turbulence, and the entrainment of trailing bubbles in the wake region of the preceding bubble. The disintegration mechanisms include the break-up by turbulence impact, shearing-off at the rim of large cap bubbles and the break-up of large cap

Comparative study of boron transport models in NRC Thermal-Hydraulic Code Trace

Energy Technology Data Exchange (ETDEWEB)

Olmo-Juan, Nicolás; Barrachina, Teresa; Miró, Rafael; Verdú, Gumersindo; Pereira, Claubia, E-mail: nioljua@iqn.upv.es, E-mail: tbarrachina@iqn.upv.es, E-mail: rmiro@iqn.upv.es, E-mail: gverdu@iqn.upv.es, E-mail: claubia@nuclear.ufmg.br [Institute for Industrial, Radiophysical and Environmental Safety (ISIRYM). Universitat Politècnica de València (Spain); Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear

2017-07-01

Recently, the interest in the study of various types of transients involving changes in the boron concentration inside the reactor, has led to an increase in the interest of developing and studying new models and tools that allow a correct study of boron transport. Therefore, a significant variety of different boron transport models and spatial difference schemes are available in the thermal-hydraulic codes, as TRACE. According to this interest, in this work it will be compared the results obtained using the different boron transport models implemented in the NRC thermal-hydraulic code TRACE. To do this, a set of models have been created using the different options and configurations that could have influence in boron transport. These models allow to reproduce a simple event of filling or emptying the boron concentration in a long pipe. Moreover, with the aim to compare the differences obtained when one-dimensional or three-dimensional components are chosen, it has modeled many different cases using only pipe components or a mix of pipe and vessel components. In addition, the influence of the void fraction in the boron transport has been studied and compared under close conditions to BWR commercial model. A final collection of the different cases and boron transport models are compared between them and those corresponding to the analytical solution provided by the Burgers equation. From this comparison, important conclusions are drawn that will be the basis of modeling the boron transport in TRACE adequately. (author)

Formulating Fine to Medium Sand Erosion for Suspended Sediment Transport Models

Directory of Open Access Journals (Sweden)

François Dufois

2015-08-01

Full Text Available The capacity of an advection/diffusion model to predict sand transport under varying wave and current conditions is evaluated. The horizontal sand transport rate is computed by vertical integration of the suspended sediment flux. A correction procedure for the near-bed concentration is proposed so that model results are independent of the vertical resolution. The method can thus be implemented in regional models with operational applications. Simulating equilibrium sand transport rates, when erosion and deposition are balanced, requires a new empirical erosion law that involves the non-dimensional excess shear stress and a parameter that depends on the size of the sand grain. Comparison with several datasets and sediment transport formulae demonstrated the model’s capacity to simulate sand transport rates for a large range of current and wave conditions and sand diameters in the range 100–500 μm. Measured transport rates were predicted within a factor two in 67% of cases with current only and in 35% of cases with both waves and current. In comparison with the results obtained by Camenen and Larroudé (2003, who provided the same indicators for several practical transport rate formulations (whose means are respectively 72% and 37%, the proposed approach gives reasonable results. Before fitting a new erosion law to our model, classical erosion rate formulations were tested but led to poor comparisons with expected sediment transport rates. We suggest that classical erosion laws should be used with care in advection/diffusion models similar to ours, and that at least a full validation procedure for transport rates involving a range of sand diameters and hydrodynamic conditions should be carried out.

Modeling emissions for three-dimensional atmospheric chemistry transport models.

Science.gov (United States)

Matthias, Volker; Arndt, Jan A; Aulinger, Armin; Bieser, Johannes; Denier Van Der Gon, Hugo; Kranenburg, Richard; Kuenen, Jeroen; Neumann, Daniel; Pouliot, George; Quante, Markus

2018-01-24

Poor air quality is still a threat for human health in many parts of the world. In order to assess measures for emission reductions and improved air quality, three-dimensional atmospheric chemistry transport modeling systems are used in numerous research institutions and public authorities. These models need accurate emission data in appropriate spatial and temporal resolution as input. This paper reviews the most widely used emission inventories on global and regional scale and looks into the methods used to make the inventory data model ready. Shortcomings of using standard temporal profiles for each emission sector are discussed and new methods to improve the spatio-temporal distribution of the emissions are presented. These methods are often neither top-down nor bottom-up approaches but can be seen as hybrid methods that use detailed information about the emission process to derive spatially varying temporal emission profiles. These profiles are subsequently used to distribute bulk emissions like national totals on appropriate grids. The wide area of natural emissions is also summarized and the calculation methods are described. Almost all types of natural emissions depend on meteorological information, which is why they are highly variable in time and space and frequently calculated within the chemistry transport models themselves. The paper closes with an outlook for new ways to improve model ready emission data, for example by using external databases about road traffic flow or satellite data to determine actual land use or leaf area. In a world where emission patterns change rapidly, it seems appropriate to use new types of statistical and observational data to create detailed emission data sets and keep emission inventories up-to-date. Emission data is probably the most important input for chemistry transport model (CTM) systems. It needs to be provided in high temporal and spatial resolution and on a grid that is in agreement with the CTM grid. Simple

Anomalous solute transport in saturated porous media: Relating transport model parameters to electrical and nuclear magnetic resonance properties

Science.gov (United States)

Swanson, Ryan D; Binley, Andrew; Keating, Kristina; France, Samantha; Osterman, Gordon; Day-Lewis, Frederick D.; Singha, Kamini

2015-01-01

The advection-dispersion equation (ADE) fails to describe commonly observed non-Fickian solute transport in saturated porous media, necessitating the use of other models such as the dual-domain mass-transfer (DDMT) model. DDMT model parameters are commonly calibrated via curve fitting, providing little insight into the relation between effective parameters and physical properties of the medium. There is a clear need for material characterization techniques that can provide insight into the geometry and connectedness of pore spaces related to transport model parameters. Here, we consider proton nuclear magnetic resonance (NMR), direct-current (DC) resistivity, and complex conductivity (CC) measurements for this purpose, and assess these methods using glass beads as a control and two different samples of the zeolite clinoptilolite, a material that demonstrates non-Fickian transport due to intragranular porosity. We estimate DDMT parameters via calibration of a transport model to column-scale solute tracer tests, and compare NMR, DC resistivity, CC results, which reveal that grain size alone does not control transport properties and measured geophysical parameters; rather, volume and arrangement of the pore space play important roles. NMR cannot provide estimates of more-mobile and less-mobile pore volumes in the absence of tracer tests because these estimates depend critically on the selection of a material-dependent and flow-dependent cutoff time. Increased electrical connectedness from DC resistivity measurements are associated with greater mobile pore space determined from transport model calibration. CC was hypothesized to be related to length scales of mass transfer, but the CC response is unrelated to DDMT.

Uranium hydrogeochemical and stream sediment reconnaissance of the Kenai NTMS quadrangle, Alaska

International Nuclear Information System (INIS)

1981-08-01

This report presents results of a Hydrogeochemical and Stream Sediment Reconnaissance of the Kenai NTMS quadrangle, Alaska. In addition to this abbreviated data release, more complete data are available to the public in machine-readable form. These machine-readable data, as well as quarterly or semiannual program progress reports containing further information on the HSSR program in general, or on the Los Alamos National Laboratory portion of the program in particular, are available from DOE's Technical Library at its Grand Junction Area Office. Presented in this data release are location data, field analyses, and laboratory analyses of several different sample media. For the sake of brevity, many field site observations have not been included in this volume; these data are, however, available on the magnetic tape. Appendices A through D describe the sample media and summarize the analytical results for each medium. The data have been subdivided by one of the Los Alamos National Laboratory sorting programs of Zinkl and others (1981a) into groups of stream-sediment, lake-sediment, stream-water, lake-water, and ground-water samples. For each group which contains a sufficient number of observations, statistical tables, tables of raw data, and 1:1,000,000 scale maps of pertinent elements have been included in this report. Also included are maps showing results of multivariate statistical analyses

Uranium hydrogeochemical and stream sediment reconnaissance of the Atlin NTMS Quadrangle, Alaska

International Nuclear Information System (INIS)

Zinkl, R.J.; Shettel, D.L. Jr.; Langfeldt, S.L.; Hardy, L.C.; D'Andrea, R.F. Jr.

1982-01-01

This report presents results of a Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) of the Altin NTMS Quadrangle, Alaska. In addition to this abbreviated data release, more complete data are available to the public in machine-readable form. These machine-readable data, as well as quarterly or semiannual program progress reports containing further information on the HSSR program in general, or on the Los Alamos National Laboratory (LANL) portion of the program in particular, are available from DOE's Technical Library at its Grand Junction Area Office. Only 6 samples were taken in the Atlin Quadrangle. Appendix A describes the sample media and summarizes the analytical results for each medium. The data have been subdivided by one of the Los Alamos National Laboratory sorting programs of Zinkl and others (1981a) into stream-sediment samples. For each group which contains a sufficient number of observations, statistical tables, tables of raw data, and 1:1,000,000 scale maps of pertinent elements have been included in this report. Information on the field and analytical procedures used by the Los Alamos National laboratory during sample collection and analysis may be found in any HSSR data release prepared by the Laboratory and will not be included in this report. Chemical analysis and field data for water samples from this quadrangle were open filed by the DOE Grand Junction Office as GJX-166

Uranium hydrogeochemical and stream sediment reconnaissance of the Denver NTMS quadrangle, Colorado

International Nuclear Information System (INIS)

1981-11-01

This report presents results of a Hydrogeochemical and Stream Sediment Reconnaissance of the Denver NTMS quadrangle, Colorado. In addition to this abbreviated data release, more complete data are available to the public in machine-readable form. These machine-readable data, as well as quarterly or semiannual program progress reports containing further information on the HSSR program in general, or on the Los Alamos National Laboratory portion of the program in particular, are available from DOE's Technical Library at its Grand Junction Area Office. Presented in this data release are location data, field analyses, and laboratory analyses of several different sample media. For the sake of brevity, many field site observations have not been included in this volume; these data are, however, available on the magnetic tape. Appendices A through E describe the sample media and summarize the analytical results for each medium. The data have been subdivided by one of the Los Alamos National Laboratory sorting programs of Zinkl and others (1981a) into groups of stream-sediment, lake-sediment, stream-water, lake-water, and ground-water samples. For each group which contains a sufficient number of observations, statistical tables, tables of raw data, and 1:1,000,000 scale maps of pertinent elements have been included in this report. Also included are maps showing results of multivariate statistical analyses

Hydrogeochemical investigation of groundwater in shallow coastal aquifer of Khulna District, Bangladesh

Science.gov (United States)

Islam, S. M. Didar-Ul; Bhuiyan, Mohammad Amir Hossain; Rume, Tanjena; Azam, Gausul

2017-12-01

Groundwater acts as a lifeline in the coastal regions to meet out the domestic, drinking, irrigational and industrial needs. To investigate the hydrogeochemical characteristics of groundwater and its suitability, twenty samples were collected from the shallow tubewells of study area having screen depth 21-54 m. The water quality assessment has been carried out by evaluating the physicochemical parameters such as temperature, pH, EC, TDS and major ions i.e., Na+, K+, Ca2+, Mg2+, Cl-, SO4 2-, NO3 -, HCO3 -. Results found that, the water is slightly alkaline and brackish in nature. The trends of cations and anions are Na+ > Ca2+ > Mg2+ > K+ and Cl- > HCO3 - > SO4 2- > NO3 -, respectively and Na-Cl-HCO3 is the dominant groundwater type. The analyzed samples were also characterized with different indices, diagram and permissible limit i.e., electric conductivity (EC), total dissolved solids (TDS), chloride content (Cl), soluble sodium percentage (SSP), sodium adsorption ratio (SAR), residual sodium carbonate (RSC), magnesium adsorption ratio (MAR), Kelley's ratio (KR), Wilcox diagram and USSL diagram, and results showed that groundwater are not suitable for drinking and irrigational use. The factors responsible for the geochemical characterization were also attempted by using standard plot and it was found that mixing of seawater with entrapped water plays a significant role in the study area.

A Coupled Chemical and Mass Transport Model for Concrete Durability

DEFF Research Database (Denmark)

Jensen, Mads Mønster; Johannesson, Björn; Geiker, Mette Rica

2012-01-01

In this paper a general continuum theory is used to evaluate the service life of cement based materials, in terms of mass transport processes and chemical degradation of the solid matrix. The model established is a reactive mass transport model, based on an extended version of the Poisson-Nernst-...

ANALYTICAL AND SIMULATION PLANNING MODEL OF URBAN PASSENGER TRANSPORT

Directory of Open Access Journals (Sweden)

Andrey Borisovich Nikolaev

2017-09-01

Full Text Available The article described the structure of the analytical and simulation models to make informed decisions in the planning of urban passenger transport. Designed UML diagram that describes the relationship of classes of the proposed model. A description of the main agents of the model developed in the simulation AnyLogic. Designed user interface integration with GIS map. Also provides simulation results that allow concluding about her health and the possibility of its use in solving planning problems of urban passenger transport.

Application of isotopic and hydro-geochemical methods in identifying sources of mine inrushing water

Institute of Scientific and Technical Information of China (English)

Dou Huiping; Ma Zhiyuan; Cao Haidong; Liu Feng; Hu Weiwei; Li Ting

2011-01-01

Isotopic and hydro-geochemical surveys were carried out to identify the source of mine inrushing water at the #73003 face in the Laohutai Mine.Based on the analysis of isotopes and hydro-chemical features of surface water,groundwater from different levels and the inrushing water,a special relationship between water at the #73003 face and cretaceous water has been found.The results show that the isotopic and hydro-chemical features of the inrushing water are completely different from those of other groundwater bodies,except for the cretaceous water.The isotopic and hydrochemical characteristics of cretaceous water are similar to the inrushing water of the #73003 face,which aided with obtaining the evidence for the possible source of the inrushing water at the #73003 face.The isotope calculations show that the inrushing water at the #73003 face is a mixture of cretaceous water and Quaternary water,water from the cretaceous conglomerate is the main source,accounting for 67％ of the inrushing water,while the Quaternary water accounts for 33％.The conclusion is also supported by a study of inrushing-water channels and an active fault near the inrushing-water plot on the #73003 face.

Colloid transport in model fracture filling materials

Science.gov (United States)

Wold, S.; Garcia-Garcia, S.; Jonsson, M.

2010-12-01

Colloid transport in model fracture filling materials Susanna Wold*, Sandra García-García and Mats Jonsson KTH Chemical Science and Engineering Royal Institute of Technology, SE-100 44 Stockholm, Sweden *Corresponding author: E-mail: wold@kth.se Phone: +46 8 790 6295 In colloid transport in water-bearing fractures, the retardation depends on interactions with the fracture surface by sorption or filtration. These mechanisms are difficult to separate. A rougher surface will give a larger area available for sorption, and also when a particle is physically hindered, it approaches the surface and enables further sorption. Sorption can be explained by electrostatics were the strongest sorption on minerals always is observed at pH below pHpzc (Filby et al., 2008). The adhesion of colloids to mineral surfaces is related to the surface roughness according to a recent study (Darbha et al., 2010). There is a large variation in the characteristics of water-bearing fractures in bedrock in terms of aperture distribution, flow velocity, surface roughness, mineral distributions, presence of fracture filling material, and biological and organic material, which is hard to implement in modeling. The aim of this work was to study the transport of negatively charged colloids in model fracture filling material in relation to flow, porosity, mineral type, colloid size, and surface charge distribution. In addition, the impact on transport of colloids of mixing model fracture filling materials with different retention and immobilization capacities, determined by batch sorption experiments, was investigated. The transport of Na-montmorillonite colloids and well-defined negatively charged latex microspheres of 50, 100, and 200 nm diameter were studied in either columns containing quartz or quartz mixed with biotite. The ionic strength in the solution was exclusively 0.001 and pH 6 or 8.5. The flow rates used were 0.002, 0.03, and 0.6 mL min-1. Sorption of the colloids on the model fracture

National Uranium Resource Evaluation Program: the Hydrogeochemical Stream Sediment Reconnaissance Program at LLNL

International Nuclear Information System (INIS)

Higgins, G.H.

1980-08-01

From early 1975 to mid 1979, Lawrence Livermore National Laboratory (LLNL) participated in the Hydrogeochemical Stream Sediment Reconnaissance (HSSR), part of the National Uranium Resource Evaluation (NURE) program sponsored by the Department of Energy (DOE). The Laboratory was initially responsible for collecting, analyzing, and evaluating sediment and water samples from approximately 200,000 sites in seven western states. Eventually, however, the NURE program redefined its sampling priorities, objectives, schedules, and budgets, with the increasingly obvious result that LLNL objectives and methodologies were not compatible with those of the NURE program office, and the LLNL geochemical studies were not relevant to the program goal. The LLNL portion of the HSSR program was consequently terminated, and all work was suspended by June 1979. Of the 38,000 sites sampled, 30,000 were analyzed by instrumental neutron activation analyses (INAA), delayed neutron counting (DNC), optical emission spectroscopy (OES), and automated chloride-sulfate analyses (SC). Data from about 13,000 sites have been formally reported. From each site, analyses were published of about 30 of the 60 elements observed. Uranium mineralization has been identified at several places which were previously not recognized as potential uranium source areas, and a number of other geochemical anomalies were discovered