Modeling of Groundwater Flow and Radionuclide Transport at the Climax Mine sub-CAU, Nevada Test Site

International Nuclear Information System (INIS)

K. Pohlmann; M. Ye; D. Reeves; M. Zavarin; D. Decker; J. Chapman

2007-01-01

The Yucca Flat-Climax Mine Corrective Action Unit (CAU) on the Nevada Test Site comprises 747 underground nuclear detonations, all but three of which were conducted in alluvial, volcanic, and carbonate rocks in Yucca Flat. The remaining three tests were conducted in the very different hydrogeologic setting of the Climax Mine granite stock located in Area 15 at the northern end of Yucca Flat. As part of the Corrective Action Investigation (CAI) for the Yucca Flat-Climax Mine CAU, models of groundwater flow and radionuclide transport will be developed for Yucca Flat. However, two aspects of these CAU-scale models require focused modeling at the northern end of Yucca Flat beyond the capability of these large models. First, boundary conditions and boundary flows along the northern reaches of the Yucca Flat-Climax Mine CAU require evaluation to a higher level of detail than the CAU-scale Yucca Flat model can efficiently provide. Second, radionuclide fluxes from the Climax tests require analysis of flow and transport in fractured granite, a unique hydrologic environment as compared to Yucca Flat proper. This report describes the Climax Mine sub-CAU modeling studies conducted to address these issues, with the results providing a direct feed into the CAI for the Yucca Flat-Climax Mine CAU. Three underground nuclear detonations were conducted for weapons effects testing in the Climax stock between 1962 and 1966: Hard Hat, Pile Driver, and Tiny Tot. Though there is uncertainty regarding the position of the water table in the stock, it is likely that all three tests were conducted in the unsaturated zone. In the early 1980s, the Spent Fuel Test-Climax (SFT-C) was constructed to evaluate the feasibility of retrievable, deep geologic storage of commercial nuclear reactor wastes. Detailed mapping of fractures and faults carried out for the SFT-C studies greatly expanded earlier data sets collected in association with the nuclear tests and provided invaluable information for

Modeling of Groundwater Flow and Radionuclide Transport at the Climax Mine sub-CAU, Nevada Test Site

Energy Technology Data Exchange (ETDEWEB)

K. Pohlmann; M. Ye; D. Reeves; M. Zavarin; D. Decker; J. Chapman

2007-09-28

The Yucca Flat-Climax Mine Corrective Action Unit (CAU) on the Nevada Test Site comprises 747 underground nuclear detonations, all but three of which were conducted in alluvial, volcanic, and carbonate rocks in Yucca Flat. The remaining three tests were conducted in the very different hydrogeologic setting of the Climax Mine granite stock located in Area 15 at the northern end of Yucca Flat. As part of the Corrective Action Investigation (CAI) for the Yucca Flat-Climax Mine CAU, models of groundwater flow and radionuclide transport will be developed for Yucca Flat. However, two aspects of these CAU-scale models require focused modeling at the northern end of Yucca Flat beyond the capability of these large models. First, boundary conditions and boundary flows along the northern reaches of the Yucca Flat-Climax Mine CAU require evaluation to a higher level of detail than the CAU-scale Yucca Flat model can efficiently provide. Second, radionuclide fluxes from the Climax tests require analysis of flow and transport in fractured granite, a unique hydrologic environment as compared to Yucca Flat proper. This report describes the Climax Mine sub-CAU modeling studies conducted to address these issues, with the results providing a direct feed into the CAI for the Yucca Flat-Climax Mine CAU. Three underground nuclear detonations were conducted for weapons effects testing in the Climax stock between 1962 and 1966: Hard Hat, Pile Driver, and Tiny Tot. Though there is uncertainty regarding the position of the water table in the stock, it is likely that all three tests were conducted in the unsaturated zone. In the early 1980s, the Spent Fuel Test-Climax (SFT-C) was constructed to evaluate the feasibility of retrievable, deep geologic storage of commercial nuclear reactor wastes. Detailed mapping of fractures and faults carried out for the SFT-C studies greatly expanded earlier data sets collected in association with the nuclear tests and provided invaluable information for

Modeling Groundwater Flow and Transport of Radionuclides at Amchitka Island's Underground Nuclear Tests: Milrow, Long Shot, and Cannikin

Energy Technology Data Exchange (ETDEWEB)

Ahmed Hassan; Karl Pohlmann; Jenny Chapman

2002-11-19

Since 1963, all United States nuclear tests have been conducted underground. A consequence of this testing has been the deposition of large amounts of radioactive material in the subsurface, sometimes in direct contact with groundwater. The majority of this testing occurred on the Nevada Test Site (NTS), but a limited number of experiments were conducted in other locations. One of these locations, Amchitka Island, Alaska is the subject of this report. Three underground nuclear tests were conducted on Amchitka Island. Long Shot was an 80-kiloton-yield test conducted at a depth of 700 meters (m) on October 29, 1965 (DOE, 2000). Milrow had an announced yield of about 1,000 kilotons, and was detonated at a depth of 1,220 m on October 2, 1969. Cannikin had an announced yield less than 5,000 kilotons, and was conducted at a depth of 1,790 m on November 6, 1971. The purpose of this work is to provide a portion of the information needed to conduct a human-health risk assessment of the potential hazard posed by the three underground nuclear tests on Amchitka Island. Specifically, the focus of this work is the subsurface transport portion, including the release of radionuclides from the underground cavities and their movement through the groundwater system to the point where they seep out of the ocean floor and into the marine environment. This requires a conceptual model of groundwater flow on the island using geologic, hydrologic, and chemical information, a numerical model for groundwater flow, a conceptual model of contaminant release and transport properties from the nuclear test cavities, and a numerical model for contaminant transport. Needed for the risk assessment are estimates of the quantity of radionuclides (in terms of mass flux) from the underground tests on Amchitka that could discharge to the ocean, the time of possible discharge, and the location in terms of distance from shoreline. The radionuclide data presented here are all reported in terms of normalized

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.

Experimental tests of transport models using modulated ECH

International Nuclear Information System (INIS)

DeBoo, J.C.; Kinsey, J.E.; Bravenec, R.

1998-12-01

Both the dynamic and equilibrium thermal responses of an L-mode plasma to repetitive ECH heat pulses were measured and compared to predictions from several thermal transport models. While no model consistently agreed with all observations, the GLF23 model was most consistent with the perturbated electron and ion temperature responses for one of the cases studied which may indicate a key role played by electron modes in the core of these discharges. Generally, the IIF and MM models performed well for the perturbed electron response while the GLF23 and IFS/PPPL models agreed with the perturbed ion response for all three cases studied. No single model agreed well with the equilibrium temperature profiles measured

Phase II Transport Model of Corrective Action Unit 98: Frenchman Flat, Nevada Test Site, Nye County, Nevada, Revision 1

Energy Technology Data Exchange (ETDEWEB)

Gregg Ruskuaff

2010-01-01

This document, the Phase II Frenchman Flat transport report, presents the results of radionuclide transport simulations that incorporate groundwater radionuclide transport model statistical and structural uncertainty, and lead to forecasts of the contaminant boundary (CB) for a set of representative models from an ensemble of possible models. This work, as described in the Federal Facility Agreement and Consent Order (FFACO) Underground Test Area (UGTA) strategy (FFACO, 1996; amended 2010), forms an essential part of the technical basis for subsequent negotiation of the compliance boundary of the Frenchman Flat corrective action unit (CAU) by Nevada Division of Environmental Protection (NDEP) and National Nuclear Security Administration Nevada Site Office (NNSA/NSO). Underground nuclear testing via deep vertical shafts was conducted at the Nevada Test Site (NTS) from 1951 until 1992. The Frenchman Flat area, the subject of this report, was used for seven years, with 10 underground nuclear tests being conducted. The U.S. Department of Energy (DOE), NNSA/NSO initiated the UGTA Project to assess and evaluate the effects of underground nuclear tests on groundwater at the NTS and vicinity through the FFACO (1996, amended 2010). The processes that will be used to complete UGTA corrective actions are described in the “Corrective Action Strategy” in the FFACO Appendix VI, Revision No. 2 (February 20, 2008).

Transport Modeling Analysis to Test the Efficiency of Fish Markets in Oman

Directory of Open Access Journals (Sweden)

Khamis S. Al-Abri

2009-01-01

Full Text Available Oman’s fish exports have shown an increasing trend while supplies to the domestic market have declined, despite increased domestic demand caused by population growth and income. This study hypothesized that declining fish supplies to domestic markets were due to inefficiency of the transport function of the fish marketing system in Oman. The hypothesis was tested by comparing the observed prices of several fish species at several markets with optimal prices. The optimal prices were estimated by the dual of a fish transport cost- minimizing linear programming model. Primary data on market prices and transportation costs and quantities transported were gathered through a survey of a sample of fish transporters. The quantity demanded at market sites was estimated using secondary data. The analysis indicated that the differences between the observed prices and the estimated optimal prices were not significantly different showing that the transport function of fish markets in Oman is efficient. This implies that the increasing trend of fish exports vis-à-vis the decreasing trend of supplies to domestic markets is rational and will continue. This may not be considered to be equitable but it is efficient and may have long-term implications for national food security and have an adverse impact on the nutritional and health status of the rural poor population. Policy makers may have to recognize the trade off between the efficiency and equity implications of the fish markets in Oman and make policy decisions accordingly in order to ensure national food security.

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

Development and testing of radionuclide transport models for fractured crystalline rock. An overview of the Nagra/JNC radionuclide retardation programme

International Nuclear Information System (INIS)

Ota, Kunio; Alexander, W.R.

2001-01-01

The joint Nagra/JNC radionuclide Retardation Programme has now been ongoing for more thean 10 years with the main aim of direct testing of radionuclide transport models for fractured crystalline rocks in as realistic a manner as possible. A large programme of field, laboratory and natural analogue studies has been carried out at the Grimsel Test Site in the central Swiss Alps. The understanding and modelling of both the processes and the structures influencing radionuclide transport in fractured crystalline rocks have matured as has the experimental technology, which has contributed to develop confidence in the applicability of the underlying research models in a repository performance assessment. In this report, the successes and set-backs of this programme are discussed as is the general approach to the thorough testing of the process models and of model assumptions. (author)

Hybrid advection scheme for 3-dimensional atmospheric models. Testing and application for a study of NO{sub x} transport

Energy Technology Data Exchange (ETDEWEB)

Zubov, V.A.; Rozanov, E.V. [Main Geophysical Observatory, St.Petersburg (Russian Federation); Schlesinger, M.E.; Andronova, N.G. [Illinois Univ., Urbana-Champaign, IL (United States). Dept. of Atmospheric Sciences

1997-12-31

The problems of ozone depletion, climate change and atmospheric pollution strongly depend on the processes of production, destruction and transport of chemical species. A hybrid transport scheme was developed, consisting of the semi-Lagrangian scheme for horizontal advection and the Prather scheme for vertical transport, which have been used for the Atmospheric Chemical Transport model to calculate the distributions of different chemical species. The performance of the new hybrid scheme has been evaluated in comparison with other transport schemes on the basis of specially designed tests. The seasonal cycle of the distribution of N{sub 2}O simulated by the model, as well as the dispersion of NO{sub x} exhausted from subsonic aircraft, are in a good agreement with published data. (author) 8 refs.

Hybrid advection scheme for 3-dimensional atmospheric models. Testing and application for a study of NO{sub x} transport

Energy Technology Data Exchange (ETDEWEB)

Zubov, V A; Rozanov, E V [Main Geophysical Observatory, St.Petersburg (Russian Federation); Schlesinger, M E; Andronova, N G [Illinois Univ., Urbana-Champaign, IL (United States). Dept. of Atmospheric Sciences

1998-12-31

The problems of ozone depletion, climate change and atmospheric pollution strongly depend on the processes of production, destruction and transport of chemical species. A hybrid transport scheme was developed, consisting of the semi-Lagrangian scheme for horizontal advection and the Prather scheme for vertical transport, which have been used for the Atmospheric Chemical Transport model to calculate the distributions of different chemical species. The performance of the new hybrid scheme has been evaluated in comparison with other transport schemes on the basis of specially designed tests. The seasonal cycle of the distribution of N{sub 2}O simulated by the model, as well as the dispersion of NO{sub x} exhausted from subsonic aircraft, are in a good agreement with published data. (author) 8 refs.

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...

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

Vadose zone transport field study: Detailed test plan for simulated leak tests

International Nuclear Information System (INIS)

AL Ward; GW Gee

2000-01-01

: identify mechanisms controlling transport processes in soils typical of the hydrogeologic conditions of Hanford's waste disposal sites; reduce uncertainty in conceptual models; develop a detailed and accurate database of hydraulic and transport parameters for validation of three-dimensional numerical models; identify and evaluate advanced, cost-effective characterization methods with the potential to assess changing conditions in the vadose zone, particularly as surrogates of currently undetectable high-risk contaminants. This plan provides details for conducting field tests during FY 2000 to accomplish these objectives. Details of additional testing during FY 2001 and FY 2002 will be developed as part of the work planning process implemented by the Integration Project

Overall evaluation of the modelling of the TRUE-1 tracer tests - Task 4. The Aespoe Task Force on Modelling of Groundwater Flow and Transport of Solutes

International Nuclear Information System (INIS)

Marschall, Paul; Elert, Mark

2003-09-01

The Aespoe Task Force on Modelling of Groundwater Flow and Transport of Solutes is a forum for the international organisations supporting the Aespoe HRL Project. The purpose of the Task Force is to interact in the area of conceptual and numerical modelling of groundwater flow and solute transport in fractured rock. Task 4 of the Aespoe Modelling Task Force consists of modelling exercises in support of the TRUE-1 tracer tests. The task was carried out in 1995-2000 and consisted of several modelling exercises in support of the TRUE-1 tracer tests, including predictive modelling where experimental results were not available beforehand. This report presents an overall evaluation of the achievements of Task 4. The specific objectives of the overall evaluation were to highlight innovative and successful modelling approaches developed, to assess the stages of the task which proved most beneficial for conceptual understanding of transport processes at the TRUE-1 site and to assess the success of various steering tools. A concise summary of scientific achievements is given and conclusions drawn with respect to unresolved technical issues. Recommendations are presented that can optimise the management of future modelling tasks

Assessment of the announced North Korean nuclear test using long-range atmospheric transport and dispersion modelling.

Science.gov (United States)

De Meutter, Pieter; Camps, Johan; Delcloo, Andy; Termonia, Piet

2017-08-18

On 6 January 2016, the Democratic People's Republic of Korea announced to have conducted its fourth nuclear test. Analysis of the corresponding seismic waves from the Punggye-ri nuclear test site showed indeed that an underground man-made explosion took place, although the nuclear origin of the explosion needs confirmation. Seven weeks after the announced nuclear test, radioactive xenon was observed in Japan by a noble gas measurement station of the International Monitoring System. In this paper, atmospheric transport modelling is used to show that the measured radioactive xenon is compatible with a delayed release from the Punggye-ri nuclear test site. An uncertainty quantification on the modelling results is given by using the ensemble method. The latter is important for policy makers and helps advance data fusion, where different nuclear Test-Ban-Treaty monitoring techniques are combined.

PORFLO - a continuum model for fluid flow, heat transfer, and mass transport in porous media. Model theory, numerical methods, and computational tests

International Nuclear Information System (INIS)

Runchal, A.K.; Sagar, B.; Baca, R.G.; Kline, N.W.

1985-09-01

Postclosure performance assessment of the proposed high-level nuclear waste repository in flood basalts at Hanford requires that the processes of fluid flow, heat transfer, and mass transport be numerically modeled at appropriate space and time scales. A suite of computer models has been developed to meet this objective. The theory of one of these models, named PORFLO, is described in this report. Also presented are a discussion of the numerical techniques in the PORFLO computer code and a few computational test cases. Three two-dimensional equations, one each for fluid flow, heat transfer, and mass transport, are numerically solved in PORFLO. The governing equations are derived from the principle of conservation of mass, momentum, and energy in a stationary control volume that is assumed to contain a heterogeneous, anisotropic porous medium. Broad discrete features can be accommodated by specifying zones with distinct properties, or these can be included by defining an equivalent porous medium. The governing equations are parabolic differential equations that are coupled through time-varying parameters. Computational tests of the model are done by comparisons of simulation results with analytic solutions, with results from other independently developed numerical models, and with available laboratory and/or field data. In this report, in addition to the theory of the model, results from three test cases are discussed. A users' manual for the computer code resulting from this model has been prepared and is available as a separate document. 37 refs., 20 figs., 15 tabs

Long-term reactive transport modelling of stabilized/solidified waste: from dynamic leaching tests to disposal scenarios

Energy Technology Data Exchange (ETDEWEB)

Windt, Laurent de [Ecole des Mines de Paris, CG-Hydrodynamics and Reaction Group, 35 R. St-Honore, 77300 Fontainebleau (France)]. E-mail: laurent.dewindt@ensmp.fr; Badreddine, Rabia [INERIS, Direction des Risques Chroniques, Unite Dechets et Sites Pollues, Parc Technologique Alata BP 2, 60550 Verneuil-en-Halatte (France); Lagneau, Vincent [Ecole des Mines de Paris, CG-Hydrodynamics and Reaction Group, 35 R. St-Honore, 77300 Fontainebleau (France)

2007-01-31

Environmental impact assessment of hazardous waste disposal relies, among others, on standardized leaching tests characterized by a strong coupling between diffusion and chemical processes. In that respect, this study shows that reactive transport modelling is a useful tool to extrapolate laboratory results to site conditions characterized by lower solution/solid (L/S) ratios, site specific geometry, infiltration, etc. A cement solidified/stabilized (S/S) waste containing lead is investigated as a typical example. The reactive transport model developed in a previous study to simulate the initial state of the waste as well as laboratory batch and dynamic tests is first summarized. Using the same numerical code (HYTEC), this model is then integrated to a simplified waste disposal scenario assuming a defective cover and rain water infiltration. The coupled evolution of the S/S waste chemistry and the pollutant plume migration are modelled assessing the importance of the cracking state of the monolithic waste. The studied configurations correspond to an undamaged and fully sealed system, a few main fractures between undamaged monoliths and, finally, a dense crack-network in the monoliths. The model considers the potential effects of cracking, first the increase of rain water and carbon dioxide infiltration and, secondly, the increase of L/S ratio and reactive surfaces, using either explicit fracture representation or dual porosity approaches.

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%

Fire test of container for radioactive materials under the condition of transportation state

International Nuclear Information System (INIS)

Miyazaki, Sanae; Shimada, Hirohisa

1986-01-01

To secure the safe transportation of container for radioactive materials, furnace and open fire test for the thermal test of container are provided. Therefore, we have carried out furnace and open fire test using test model simulating a transportation state. Test model used in this test is made of stainless steel with diameter of 200 mm and length of 400 mm, and is set on the rest as in the case of transportation state. From the data on temperature measurement, some interesting results are obtained as follows. Near the surface of model, the temperature gradient in the direction perpendicular to the surface of model with the rest is greater than that without the rest. The temperature rise at the center of the model with the rest is less than that without the rest. In the experiment, temperature distributions are measured in the three radial directions. The temperature differences among three distributions in the model with rest are greater than that without rest. On the other hand, in the furnace test, the heat transfer coefficient on the surface of test model with the rest is 90 - 140 kcal/m 2 h · K for the range of furnace temperature from 700 to 950 deg C and this value is almost equal to the value without the rest. (author)

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

Analysis and model testing of a Super Tiger Type B waste transport system in accident environments

International Nuclear Information System (INIS)

May, R.A.; Yoshimura, H.R.; Romesberg, L.E.; Joseph, B.J.

1980-01-01

Sandia National Laboratories is investigating the response of a Type B packaging containing drums of contact-handled transuranic waste (CH-TRU) as a part of a program to evaluate the adequacy of experimental and analytical methods for assessing the safety of waste transport systems in accident environments. A US NRC certified Type B package known as the Super Tiger was selected for the study. This overpack consists of inner and outer steel shells separated by rigid polyurethane foam and can be used for either highway or rail transportation. Tests using scale models of the vehicular system are being conducted in conjunction with computer analyses

Evaluation of modelling of the TRUE-1 radially converging tests with sorbing tracers. The Aespoe task force on modelling of groundwater flow and transport of solutes. Tasks 4E and 4F

Energy Technology Data Exchange (ETDEWEB)

Elert, M.; Svensson, Haakan [Kemakta Konsult AB, Stockholm (Sweden)

2001-05-01

The Aespoe Task Force on Modelling of Groundwater Flow and Transport of Solutes is a forum for the international organisations supporting the Aespoe HRL Project. The purpose of the Task Force is to interact in the area of conceptual and numerical modelling of groundwater flow and solute transport in fractured rock. Task 4 of the Aespoe Modelling Task Force consists of modelling exercises in support of the TRUE-1 tracer tests. In this report, the modelling work performed within Tasks 4E and 4F is evaluated, which comprised predictive modelling of the tracer tests (STT-1, STT-1b and STT-2) performed within the TRUE-1 project using sorbing and non-sorbing tracers. The tests were made between packed off boreholes penetrating a water-conducting geological feature with a simple structure (Feature A). Nine modelling teams representing eight organisations have performed predictive modelling of the tracer tests using different modelling approaches and models. The modelling groups were initially given data from the site characterisation, data from preliminary tracer tests performed with non-sorbing tracers and data on the experimental set-up of the sorbing tracer tests. Based on this information, model predictions were made of drawdown, tracer mass recovery and tracer breakthrough. For the predictions of the STT-1b and STT-2 tests results from previous tracer tests with sorbing tracer were also available. The predictions of the sorbing tracer breakthrough in the initial tracer test (STT-1) generally underestimated the breakthrough time, suggesting the need to include additional processes and evaluate the application of the laboratory data. As a result of model calibration and modification the predictions were considerably improved for the latter tracer tests (STT-1b and STT-2). Task 4E and 4F have proved to be very valuable in increasing the understanding of non-sorbing tracer transport in fractured rock. There is a general consensus on the major processes responsible for

Test of models for electron transport in laser produced plasmas

International Nuclear Information System (INIS)

Colombant, D.G.; Manheimer, W.M.; Busquet, M.

2005-01-01

This paper examines five different models of electron thermal transport in laser produced spherical implosions. These are classical, classical with a flux limit f, delocalization, beam deposition model, and Fokker-Planck solutions. In small targets, the results are strongly dependent on f for flux limit models, with small f's generating very steep temperature gradients. Delocalization models are characterized by large preheat in the center of the target. The beam deposition model agrees reasonably well with the Fokker-Planck simulation results. For large, high gain fusion targets, the delocalization model shows the gain substantially reduced by the preheat. However, flux limitation models show gain largely independent of f, with the beam deposition model also showing the same high gain

Lessons in the Design and Characterization Testing of the Semi-Span Super-Sonic Transport (S4T) Wind-Tunnel Model

Science.gov (United States)

2012-01-01

This paper focuses on some of the more challenging design processes and characterization tests of the Semi-Span Super-Sonic Transport (S4T)-Active Controls Testbed (ACT). The model was successfully tested in four entries in the National Aeronautics and Space Administration Langley Transonic Dynamics Tunnel to satisfy the goals and objectives of the Fundamental Aeronautics Program Supersonic Project Aero-Propulso-Servo-Elastic effort. Due to the complexity of the S4T-ACT, only a small sample of the technical challenges for designing and characterizing the model will be presented. Specifically, the challenges encountered in designing the model include scaling the Technology Concept Airplane to model scale, designing the model fuselage, aileron actuator, and engine pylons. Characterization tests included full model ground vibration tests, wing stiffness measurements, geometry measurements, proof load testing, and measurement of fuselage static and dynamic properties.

Report on stages 3 and 4: testing of coupled chemical transport models

International Nuclear Information System (INIS)

Read, D.

1991-01-01

Chemval is an international exercise aimed at the verification and validation of predictive models describing groundwater speciation and geochemical transport. As a component of the CEC Mirage project (Migration of radionuclides in the geosphere) - second phase, Chemval is being carried out within the framework of the third Community R and D programme on radioactive waste management and storage (1985-89). This report describes the methodology employed and results obtained for 15 verification tests of varying complexity. The outcome of validation studies against two well-characterized experimental systems is also assessed in terms of the requirements for radiological risk assessment. Chemval is funded jointly by the Commission of the European Communities and Her majesty's Inspectorate of Pollution - UK Department of the Environment. 75 refs., 67 figs; 21 tabs

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.

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.)

An experimental program for testing the validity of flow and transport models in unsaturated tuff: The Yucca Mountain Project

International Nuclear Information System (INIS)

Shephard, L.E.; Glass, R.J.; Siegel, M.D.; Tidwell, V.C.

1990-01-01

Groundwater flow and contaminant transport through the unsaturated zone are receiving increased attention as options for waste disposal in saturated media continue to be considered as a potential means for resolving the nation's waste management concerns. An experimental program is being developed to test the validity of conceptual flow and transport models that are being formulated to predict the long-term performance at Yucca Mountain. This program is in the developmental stage and will continue to evolve as information is acquired and knowledge is improved with reference to flow and transport in unsaturated fractured media. The general approach for directing the validation effort entails identifying those processes which may cause the site to fail relative to imposed regulatory requirements, evaluating the key assumptions underlying the conceptual models used or developed to describe these processes, and developing new conceptual models as needed. Emphasis is currently being placed in four general areas: flow and transport in unsaturated fractures; fracture-matrix interactions; infiltration flow instability; and evaluation of scale effects in heterogeneous fractured media. Preliminary results and plans or each of these areas for both the laboratory and field investigation components will be presented in the manuscript. 1 ref

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)

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

Validation Analysis of the Groundwater Flow and Transport Model of the Central Nevada Test Area

Energy Technology Data Exchange (ETDEWEB)

A. Hassan; J. Chapman; H. Bekhit; B. Lyles; K. Pohlmann

2006-09-30

The Central Nevada Test Area (CNTA) is a U.S. Department of Energy (DOE) site undergoing environmental restoration. The CNTA is located about 95 km northeast of Tonopah, Nevada, and 175 km southwest of Ely, Nevada (Figure 1.1). It was the site of the Faultless underground nuclear test conducted by the U.S. Atomic Energy Commission (DOE's predecessor agency) in January 1968. The purposes of this test were to gauge the seismic effects of a relatively large, high-yield detonation completed in Hot Creek Valley (outside the Nevada Test Site [NTS]) and to determine the suitability of the site for future large detonations. The yield of the Faultless underground nuclear test was between 200 kilotons and 1 megaton (DOE, 2000). A three-dimensional flow and transport model was created for the CNTA site (Pohlmann et al., 1999) and determined acceptable by DOE and the Nevada Division of Environmental Protection (NDEP) for predicting contaminant boundaries for the site.

Multiple-tracer tests for contaminant transport process identification in saturated municipal solid waste

International Nuclear Information System (INIS)

Woodman, N.D.; Rees-White, T.C.; Stringfellow, A.M.; Beaven, R.P.; Hudson, A.P.

2015-01-01

Highlights: • Multiple tracers were applied to saturated MSW to test dual-porosity properties. • Lithium demonstrated to be non-conservative as a tracer. • 260 mm diameter column too small to test transport properties of MSW. • The classical advection-dispersion mode was rejected due to high dispersivity. • Characteristic diffusion times did not vary with the tracer. - Abstract: Two column tests were performed in conditions emulating vertical flow beneath the leachate table in a biologically active landfill to determine dominant transport mechanisms occurring in landfills. An improved understanding of contaminant transport process in wastes is required for developing better predictions about potential length of the long term aftercare of landfills, currently measured in timescales of centuries. Three tracers (lithium, bromide and deuterium) were used. Lithium did not behave conservatively. Given that lithium has been used extensively for tracing in landfill wastes, the tracer itself and the findings of previous tests which assume that it has behaved conservatively may need revisiting. The smaller column test could not be fitted with continuum models, probably because the volume of waste was below a representative elemental volume. Modelling compared advection-dispersion (AD), dual porosity (DP) and hybrid AD–DP models. Of these models, the DP model was found to be the most suitable. Although there is good evidence to suggest that diffusion is an important transport mechanism, the breakthrough curves of the different tracers did not differ from each other as would be predicted based on the free-water diffusion coefficients. This suggested that solute diffusion in wastes requires further study

Multiple-tracer tests for contaminant transport process identification in saturated municipal solid waste

Energy Technology Data Exchange (ETDEWEB)

Woodman, N.D., E-mail: n.d.woodman@soton.ac.uk; Rees-White, T.C.; Stringfellow, A.M.; Beaven, R.P.; Hudson, A.P.

2015-04-15

Highlights: • Multiple tracers were applied to saturated MSW to test dual-porosity properties. • Lithium demonstrated to be non-conservative as a tracer. • 260 mm diameter column too small to test transport properties of MSW. • The classical advection-dispersion mode was rejected due to high dispersivity. • Characteristic diffusion times did not vary with the tracer. - Abstract: Two column tests were performed in conditions emulating vertical flow beneath the leachate table in a biologically active landfill to determine dominant transport mechanisms occurring in landfills. An improved understanding of contaminant transport process in wastes is required for developing better predictions about potential length of the long term aftercare of landfills, currently measured in timescales of centuries. Three tracers (lithium, bromide and deuterium) were used. Lithium did not behave conservatively. Given that lithium has been used extensively for tracing in landfill wastes, the tracer itself and the findings of previous tests which assume that it has behaved conservatively may need revisiting. The smaller column test could not be fitted with continuum models, probably because the volume of waste was below a representative elemental volume. Modelling compared advection-dispersion (AD), dual porosity (DP) and hybrid AD–DP models. Of these models, the DP model was found to be the most suitable. Although there is good evidence to suggest that diffusion is an important transport mechanism, the breakthrough curves of the different tracers did not differ from each other as would be predicted based on the free-water diffusion coefficients. This suggested that solute diffusion in wastes requires further study.

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

Ion and solvent Transport in Polypyrrole: Experimental Test of Osmotic Model

DEFF Research Database (Denmark)

Velmurugu, Yogambigai; Skaarup, Steen

2005-01-01

Ion and solvent transport in the conjugated polymer actuator material, polypyrrole, doped with the immobile anion dodecyl benzene sulphonate, has been investigated by simultaneous cyclic voltammetry and Electrochemical Quartz Crystal Microbalance measurements. The purpose was to elucidate the pre...... from almost pure cation transport to ca. equal amount of anion transport; exchanging Br- for Cl- ions has only negligible effect at lower concentrations at equal osmotic pressures. Ca. 4 H2O molecules are tightly bound to each Na+ ion at concentrations ... the precise nature of the mobile species during redox cycling, and to seek confirmation for the osmotic mechanism of actuation. Three testable aspects of the model were confirmed: The number of inserted H2O molecules decreases with electrolyte concentration; at the same time the mechanism gradually changes...

Reconstructing solar magnetic fields from historical observations: Testing the surface flux transport model

Science.gov (United States)

Virtanen, Iiro; Virtanen, Ilpo; Pevtsov, Alexei; Yeates, Anthony; Mursula, Kalevi

2017-04-01

We aim to use the surface flux transport model to simulate the long-term evolution of the photospheric magnetic field from historical observations. In this work we study the accuracy of the model and its sensitivity to uncertainties in its main parameters and the input data. We test the model by running simulations with different values of meridional circulation and supergranular diffusion parameters, and study how the flux distribution inside active regions and the initial magnetic field affect the simulation. We compare the results to assess how sensitive the simulation is to uncertainties in meridional circulation speed, supergranular diffusion and input data. We also compare the simulated magnetic field with observations. We find that there is generally good agreement between simulations and observations. While the model is not capable of replicating fine details of the magnetic field, the long-term evolution of the polar field is very similar in simulations and observations. Simulations typically yield a smoother evolution of polar fields than observations, that often include artificial variations due to observational limitations. We also find that the simulated field is fairly insensitive to uncertainties in model parameters or the input data. Due to the decay term included in the model the effects of the uncertainties are rather minor or temporary, lasting typically one solar cycle.

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

Transport simulations of TFTR experiments to test theoretical models for χe and χi

International Nuclear Information System (INIS)

Redi, M.H.; Bateman, G.

1990-08-01

1-1/2-d BALDUR transport code predictions using recent theoretically-based models for thermal and particle transport are compared to measured profiles of electron plasma density and electron and ion temperatures for TFTR ohmic, L-mode and supershot discharges. The profile consistent drift wave model is found to overestimate ion temperatures at high heating powers, so that a third mode or loss process is needed in addition to drift wave transport (TEM, η i ) and an edge loss model. None of several versions of local multiple mode models, using the 1989 Carreras-Diamond resistive ballooning model, gives T e , T i within 20% for all three TFTR regimes studied. 36 refs., 7 figs., 4 tabs

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.

Evaluation of modelling of the TRUE-1 radially converging and dipole tests with conservative tracers. The Aespoe task force on modelling of groundwater flow and transport of solutes. Tasks 4C and 4D

International Nuclear Information System (INIS)

Elert, M.

1999-05-01

The 'Aespoe task force on modelling of groundwater flow and transport of solutes' is a forum for the international organisations supporting the Aespoe HRL Project. The purpose of the Task Force is to interact in the area of conceptual and numerical modelling of groundwater flow and solute transport in fractured rock. Task 4 of the Aespoe Modelling Task Force consists of modelling exercises in support of the TRUE-1 tracer tests. In this report, the modelling work performed within Tasks 4C and 4D is evaluated, which comprised predictive modelling of the radially converging tracer tests and dipole tracer tests performed within the TRUE-1 tests using non-sorbing tracers. The tests were performed between packed off boreholes penetrating a water-conducting geological feature with a simple structure (Feature A). These tests are to a great extent preparatory steps for the subsequent tests with sorbing radioactive tracers. In Tasks 4E and 4F of the Aespoe Modelling Task Force predictive modelling of the sorbing tracer tests is performed. Eight modelling teams representing seven organisations have performed predictive modelling using different modelling approaches and models. The modelling groups were initially given data from the site characterisation and data on the experimental set-up of the tracer tests. Based on this information model predictions were performed of drawdown, tracer mass recovery and tracer breakthrough. The performed predictions shows that the concept of Feature A as a singular well-connected feature with limited connectivity to its surroundings is quite adequate for predictions of drawdown in boreholes and conservative tracer breakthrough. Reasonable estimates were obtained using relatively simple models. However, more elaborate models with calibration or conditioning of transmissivities and transport apertures are required for more accurate predictions. The general flow and transport processes are well understood, but the methodology to derive the

Evaluation of modelling of the TRUE-1 radially converging and dipole tests with conservative tracers. The Aespoe task force on modelling of groundwater flow and transport of solutes. Tasks 4C and 4D

Energy Technology Data Exchange (ETDEWEB)

Elert, M. [Kemakta Konsult AB, Stockholm (Sweden)

1999-05-01

The `Aespoe task force on modelling of groundwater flow and transport of solutes` is a forum for the international organisations supporting the Aespoe HRL Project. The purpose of the Task Force is to interact in the area of conceptual and numerical modelling of groundwater flow and solute transport in fractured rock. Task 4 of the Aespoe Modelling Task Force consists of modelling exercises in support of the TRUE-1 tracer tests. In this report, the modelling work performed within Tasks 4C and 4D is evaluated, which comprised predictive modelling of the radially converging tracer tests and dipole tracer tests performed within the TRUE-1 tests using non-sorbing tracers. The tests were performed between packed off boreholes penetrating a water-conducting geological feature with a simple structure (Feature A). These tests are to a great extent preparatory steps for the subsequent tests with sorbing radioactive tracers. In Tasks 4E and 4F of the Aespoe Modelling Task Force predictive modelling of the sorbing tracer tests is performed. Eight modelling teams representing seven organisations have performed predictive modelling using different modelling approaches and models. The modelling groups were initially given data from the site characterisation and data on the experimental set-up of the tracer tests. Based on this information model predictions were performed of drawdown, tracer mass recovery and tracer breakthrough. The performed predictions shows that the concept of Feature A as a singular well-connected feature with limited connectivity to its surroundings is quite adequate for predictions of drawdown in boreholes and conservative tracer breakthrough. Reasonable estimates were obtained using relatively simple models. However, more elaborate models with calibration or conditioning of transmissivities and transport apertures are required for more accurate predictions. The general flow and transport processes are well understood, but the methodology to derive the

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.

Transport processes in partially saturate concrete: Testing and liquid properties

Science.gov (United States)

Villani, Chiara

The measurement of transport properties of concrete is considered by many to have the potential to serve as a performance criterion that can be related to concrete durability. However, the sensitivity of transport tests to several parameters combined with the low permeability of concrete complicates the testing. Gas permeability and diffusivity test methods are attractive due to the ease of testing, their non-destructive nature and their potential to correlate to in-field carbonation of reinforced concrete structures. This work was aimed at investigating the potential of existing gas transport tests as a way to reliably quantify transport properties in concrete. In this study gas permeability and diffusivity test methods were analyzed comparing their performance in terms of repeatability and variability. The influence of several parameters was investigated such as moisture content, mixture proportions and gas flow. A closer look to the influence of pressure revealed an anomalous trend of permeability with respect to pressure. An alternative calculation is proposed in an effort to move towards the determination of intrinsic material properties that can serve as an input for service life prediction models. The impact of deicing salts exposure was also analyzed with respect to their alteration of the degree of saturation as this may affect gas transport in cementitious materials. Limited information were previously available on liquid properties over a wide range of concentrations. To overcome this limitation, this study quantified surface tension, viscosity in presence of deicing salts in a broad concentration range and at different temperatures. Existing models were applied to predict the change of fluid properties during drying. Vapor desorption isotherms were obtained to investigate the influence of deicing salts presence on the non-linear moisture diffusion coefficient. Semi-empirical models were used to quantify the initiation and the rate of drying using liquid

Test for radioactive material transport package safety

International Nuclear Information System (INIS)

Li Guoqiang; Zhao Bing; Zhang Jiangang; Wang Xuexin; Ma Anping

2012-01-01

Regulations on radioactive material transport in China were introduced. Test facilities and data acquiring instruments for radioactive material package in China Institute for Radiation Protection were also introduced in this paper, which were used in drop test and thermal test. Test facilities were constructed according to the requirements of IAEA's 'Regulations for the Safe Transport of Radioactive Material' (TS-R-l) and Chinese 'Regulations for the Safe Transport of Radioactive Material' (GB 11806-2004). Drop test facilities were used in free drop test, penetration test, mechanical test (free drop test Ⅰ, free drop test Ⅱ and free drop test Ⅲ) of type A and type B packages weighing less than thirteen tons. Thermal test of type B packages can be carried out in the thermal test facilities. Certification tests of type FCo70-YQ package, type 30A-HB-01 package, type SY-I package and type XAYT-I package according to regulations were done using these facilities. (authors)

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.

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.

Testing of a transport cask for research reactor spent fuel

International Nuclear Information System (INIS)

Mourao, Rogerio P.; Silva, Luiz Leite da; Miranda, Carlos A.; Mattar Neto, Miguel; Quintana, Jose F.A.; Saliba, Roberto O.; Novara, Oscar E.

2011-01-01

Since the beginning of the last decade three Latin American countries which operate research reactors - Argentina, Brazil and Chile - have been joining efforts to improve the regional capability in the management of spent fuel elements from the reactors operated in the region. As a step in this direction, a packaging for the transport of irradiated fuel from research reactors was designed by a tri-national team and a half-scale model for MTR fuel constructed in Argentina and tested in Brazil. Two test campaigns have been carried out so far, covering both normal conditions of transportation and hypothetical accident conditions. Although the specimen has not successfully performed the tests, its overall performance was considered very satisfactory, and improvements are being introduced to the design. A third test sequence is planned for 2011. (author)

Thermal simulations and tests in the development of a helmet transport spent fuel elements Research Reactor

International Nuclear Information System (INIS)

Saliba, R.; Quintana, F.; Márquez Turiello, R.; Furnari, J.C.; Pimenta Mourão, R.

2013-01-01

A packaging for the transport of irradiated fuel from research reactors was designed by a group of researchers to improve the capability in the management of spent fuel elements from the reactors operated in the region. Two half-scale models for MTR fuel were constructed and tested so far and a third one for both MTR and TRIGA fuels will be constructed and tested next. Four test campaigns have been carried out, covering both normal and hypothetical accident conditions of transportation. The thermal test is part of the requirements for the qualification of transportation packages for nuclear reactors spent fuel elements. In this paper both the numerical modelling and experimental thermal tests performed are presented and discussed. The cask is briefly described as well as the finite element model developed and the main adopted hypotheses for the thermal phenomena. The results of both numerical runs and experimental tests are discussed as a tool to validate the thermal modelling. The impact limiters, attached to the cask for protection, were not modelled. (author) [es

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

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

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.

Testing of materials and scale models for impact limiters

International Nuclear Information System (INIS)

Maji, A.K.; Satpathi, D.; Schryer, H.L.

1991-01-01

Aluminum Honeycomb and Polyurethane foam specimens were tested to obtain experimental data on the material's behavior under different loading conditions. This paper reports the dynamic tests conducted on the materials and on the design and testing of scale models made out of these open-quotes Impact Limiters,close quotes as they are used in the design of transportation casks. Dynamic tests were conducted on a modified Charpy Impact machine with associated instrumentation, and compared with static test results. A scale model testing setup was designed and used for preliminary tests on models being used by current designers of transportation casks. The paper presents preliminary results of the program. Additional information will be available and reported at the time of presentation of the paper

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

Changes of peritoneal transport parameters with time on dialysis: assessment with sequential peritoneal equilibration test.

Science.gov (United States)

Waniewski, Jacek; Antosiewicz, Stefan; Baczynski, Daniel; Poleszczuk, Jan; Pietribiasi, Mauro; Lindholm, Bengt; Wankowicz, Zofia

2017-10-27

Sequential peritoneal equilibration test (sPET) is based on the consecutive performance of the peritoneal equilibration test (PET, 4-hour, glucose 2.27%) and the mini-PET (1-hour, glucose 3.86%), and the estimation of peritoneal transport parameters with the 2-pore model. It enables the assessment of the functional transport barrier for fluid and small solutes. The objective of this study was to check whether the estimated model parameters can serve as better and earlier indicators of the changes in the peritoneal transport characteristics than directly measured transport indices that depend on several transport processes. 17 patients were examined using sPET twice with the interval of about 8 months (230 ± 60 days). There was no difference between the observational parameters measured in the 2 examinations. The indices for solute transport, but not net UF, were well correlated between the examinations. Among the estimated parameters, a significant decrease between the 2 examinations was found only for hydraulic permeability LpS, and osmotic conductance for glucose, whereas the other parameters remained unchanged. These fluid transport parameters did not correlate with D/P for creatinine, although the decrease in LpS values between the examinations was observed mostly for patients with low D/P for creatinine. We conclude that changes in fluid transport parameters, hydraulic permeability and osmotic conductance for glucose, as assessed by the pore model, may precede the changes in small solute transport. The systematic assessment of fluid transport status needs specific clinical and mathematical tools beside the standard PET tests.

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

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

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

Characteristics of Control Laws Tested on the Semi-Span Super-Sonic Transport (S4T) Wind-Tunnel Model

Science.gov (United States)

Christhilf, David M.; Moulin, Boris; Ritz, Erich; Chen, P. C.; Roughen, Kevin M.; Perry, Boyd

2012-01-01

The Semi-Span Supersonic Transport (S4T) is an aeroelastically scaled wind-tunnel model built to test active controls concepts for large flexible supersonic aircraft in the transonic flight regime. It is one of several models constructed in the 1990's as part of the High Speed Research (HSR) Program. Control laws were developed for the S4T by M4 Engineering, Inc. and by Zona Technologies, Inc. under NASA Research Announcement (NRA) contracts. The model was tested in the NASA-Langley Transonic Dynamics Tunnel (TDT) four times from 2007 to 2010. The first two tests were primarily for plant identification. The third entry was used for testing control laws for Ride Quality Enhancement, Gust Load Alleviation, and Flutter Suppression. Whereas the third entry only tested FS subcritically, the fourth test demonstrated closed-loop operation above the open-loop flutter boundary. The results of the third entry are reported elsewhere. This paper reports on flutter suppression results from the fourth wind-tunnel test. Flutter suppression is seen as a way to provide stability margins while flying at transonic flight conditions without penalizing the primary supersonic cruise design condition. An account is given for how Controller Performance Evaluation (CPE) singular value plots were interpreted with regard to progressing open- or closed-loop to higher dynamic pressures during testing.

Large Payload Ground Transportation and Test Considerations

Science.gov (United States)

Rucker, Michelle A.

2016-01-01

Many spacecraft concepts under consideration by the National Aeronautics and Space Administration’s (NASA’s) Evolvable Mars Campaign take advantage of a Space Launch System payload shroud that may be 8 to 10 meters in diameter. Large payloads can theoretically save cost by reducing the number of launches needed--but only if it is possible to build, test, and transport a large payload to the launch site in the first place. Analysis performed previously for the Altair project identified several transportation and test issues with an 8.973 meters diameter payload. Although the entire Constellation Program—including Altair—has since been canceled, these issues serve as important lessons learned for spacecraft designers and program managers considering large payloads for future programs. A transportation feasibility study found that, even broken up into an Ascent and Descent Module, the Altair spacecraft would not fit inside available aircraft. Ground transportation of such large payloads over extended distances is not generally permitted, so overland transportation alone would not be an option. Limited ground transportation to the nearest waterway may be possible, but water transportation could take as long as 67 days per production unit, depending on point of origin and acceptance test facility; transportation from the western United States would require transit through the Panama Canal to access the Kennedy Space Center launch site. Large payloads also pose acceptance test and ground processing challenges. Although propulsion, mechanical vibration, and reverberant acoustic test facilities at NASA’s Plum Brook Station have been designed to accommodate large spacecraft, special handling and test work-arounds may be necessary, which could increase cost, schedule, and technical risk. Once at the launch site, there are no facilities currently capable of accommodating the combination of large payload size and hazardous processing such as hypergolic fuels

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

Concept on groundwater flow and mass transport through heterogeneous porous media and application to in-situ test analysis

International Nuclear Information System (INIS)

Hatanaka, Koichiro; Umeki, Hiroyuki.

1995-01-01

Generally, geological media is modelled as porous or fractured media depending on their characteristics. Since the channels of groundwater flow and the transport paths are determined by the heterogeneity of the geological media, quantitative understanding of the heterogeneity is an important issue for modelling flow and transport processes through them. Therefore, it becomes popular way to develop statistical identification approaches of the heterogeneous field by using data from in-situ test and conduct validation studies of flow and transport models through the field by comparing with observed data. In this report, the theories of the identification approach and the concept on groundwater flow and mass transport are explained briefly and the application to tracer tests conducted at Grimsel test site, Switzerland, are described. (author)

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.

Mathematical model of statistical identification of information support of road transport

Directory of Open Access Journals (Sweden)

V. G. Kozlov

2016-01-01

Full Text Available In this paper based on the statistical identification method using the theory of self-organizing systems, built multifactor model the relationship of road transport and training system. Background information for the model represented by a number of parameters of average annual road transport operations and information provision, including training complex system parameters (inputs, road management and output parameters. Ask two criteria: stability criterion model and test correlation. The program determines their minimum, and is the only model of optimal complexity. The predetermined number of parameters established mathematical relationship of each output parameter with the others. To improve the accuracy and regularity of the forecast of the interpolation nodes allocated in the test data sequence. Other data form the training sequence. Decision model based on the principle of selection. Running it with the gradual complication of the mathematical description and exhaustive search of all possible variants of the models on the specified criteria. Advantages of the proposed model: adequately reflects the actual process, allows you to enter any additional input parameters and determine their impact on the individual output parameters of the road transport, allows in turn change the values of key parameters in a certain ratio and to determine the appropriate changes the output parameters of the road transport, allows to predict the output parameters road transport operations.

GRRR. The EXPECT groundwater model for transport of solutes

NARCIS (Netherlands)

Meijers R; Sauter FJ; Veling EJM; van Grinsven JJM; Leijnse A; Uffink GJM; MTV; CWM; LBG

1994-01-01

In this report the design and first test results are presented of the EXPECT groundwater module for transport of solutes GRRR (GRoundwater source Receptor Relationships). This model is one of the abiotic compartment modules of the EXPECT model. The EXPECT model is a tool for scenario development

Hydride transport vessel vibration and shock test report

Energy Technology Data Exchange (ETDEWEB)

Tipton, D.G.

1998-06-01

Sandia National Laboratories performed vibration and shock testing on a Savannah River Hydride Transport Vessel (HTV) which is used for bulk shipments of tritium. This testing is required to qualify the HTV for transport in the H1616 shipping container. The main requirement for shipment in the H1616 is that the contents (in this case the HTV) have a tritium leak rate of less than 1x10{sup {minus}7} cc/sec after being subjected to shock and vibration normally incident to transport. Helium leak tests performed before and after the vibration and shock testing showed that the HTV remained leaktight under the specified conditions. This report documents the tests performed and the test results.

Hydride transport vessel vibration and shock test report

International Nuclear Information System (INIS)

Tipton, D.G.

1998-06-01

Sandia National Laboratories performed vibration and shock testing on a Savannah River Hydride Transport Vessel (HTV) which is used for bulk shipments of tritium. This testing is required to qualify the HTV for transport in the H1616 shipping container. The main requirement for shipment in the H1616 is that the contents (in this case the HTV) have a tritium leak rate of less than 1x10 -7 cc/sec after being subjected to shock and vibration normally incident to transport. Helium leak tests performed before and after the vibration and shock testing showed that the HTV remained leaktight under the specified conditions. This report documents the tests performed and the test results

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)

Modeling of radiocesium transport kinetics in system water-aquatic plants

International Nuclear Information System (INIS)

Svadlenkova, M.

1988-01-01

Compartment models were used to describe the kinetics of the transport of radionuclides in the system water-biomass of aquatic plants. Briefly described are linear models and models with time variable parameters. The model was tested using data from a locality in the environs of the Bohunice nuclear power plant. Cladophora glomerata algae were the monitored plants, 137 Cs the monitored radionuclide. The models may be used when aquatic plants serve as bioindicators of the radioactive contamination of surface waters, for monitoring the transport of radionuclides in food chains. (M.D.). 10 refs

Design and tests of a package for the transport of radioactive sources; Projeto e testes de uma embalagem para o transporte de fontes radioativas

Energy Technology Data Exchange (ETDEWEB)

Santos, Paulo de Oliveira, E-mail: pos@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2011-10-26

The Type A package was designed for transportation of seven cobalt-60 sources with total activity of 1 GBq. The shield thickness to accomplish the dose rate and the transport index established by the radioactive transport regulation was calculated by the code MCNP (Monte Carlo N-Particle Transport Code Version 5). The sealed cobalt-60 sources were tested for leakages. according to the regulation ISO 9978:1992 (E). The package was tested according to regulation Radioactive Material Transport CNEN. The leakage tests results pf the sources, and the package tests demonstrate that the transport can be safe performed from the CDTN to the steelmaking industries

The Couplex test cases: models and lessons

International Nuclear Information System (INIS)

Bourgeat, A.; Kern, M.; Schumacher, S.; Talandier, J.

2003-01-01

The Couplex test cases are a set of numerical test models for nuclear waste deep geological disposal simulation. They are centered around the numerical issues arising in the near and far field transport simulation. They were used in an international contest, and are now becoming a reference in the field. We present the models used in these test cases, and show sample results from the award winning teams. (authors)

Conducting field studies for testing pesticide leaching models

Science.gov (United States)

Smith, Charles N.; Parrish, Rudolph S.; Brown, David S.

1990-01-01

A variety of predictive models are being applied to evaluate the transport and transformation of pesticides in the environment. These include well known models such as the Pesticide Root Zone Model (PRZM), the Risk of Unsaturated-Saturated Transport and Transformation Interactions for Chemical Concentrations Model (RUSTIC) and the Groundwater Loading Effects of Agricultural Management Systems Model (GLEAMS). The potentially large impacts of using these models as tools for developing pesticide management strategies and regulatory decisions necessitates development of sound model validation protocols. This paper offers guidance on many of the theoretical and practical problems encountered in the design and implementation of field-scale model validation studies. Recommendations are provided for site selection and characterization, test compound selection, data needs, measurement techniques, statistical design considerations and sampling techniques. A strategy is provided for quantitatively testing models using field measurements.

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

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

Reconstructing solar magnetic fields from historical observations. II. Testing the surface flux transport model

Science.gov (United States)

Virtanen, I. O. I.; Virtanen, I. I.; Pevtsov, A. A.; Yeates, A.; Mursula, K.

2017-07-01

Aims: We aim to use the surface flux transport model to simulate the long-term evolution of the photospheric magnetic field from historical observations. In this work we study the accuracy of the model and its sensitivity to uncertainties in its main parameters and the input data. Methods: We tested the model by running simulations with different values of meridional circulation and supergranular diffusion parameters, and studied how the flux distribution inside active regions and the initial magnetic field affected the simulation. We compared the results to assess how sensitive the simulation is to uncertainties in meridional circulation speed, supergranular diffusion, and input data. We also compared the simulated magnetic field with observations. Results: We find that there is generally good agreement between simulations and observations. Although the model is not capable of replicating fine details of the magnetic field, the long-term evolution of the polar field is very similar in simulations and observations. Simulations typically yield a smoother evolution of polar fields than observations, which often include artificial variations due to observational limitations. We also find that the simulated field is fairly insensitive to uncertainties in model parameters or the input data. Due to the decay term included in the model the effects of the uncertainties are somewhat minor or temporary, lasting typically one solar cycle.

LCLS-II CRYOMODULE TRANSPORT SYSTEM TESTING

Energy Technology Data Exchange (ETDEWEB)

Huque, Naeem [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Daly, Edward F. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); McGee, Michael W. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

2018-04-01

The Cryomodules (CM) for the Linear Coherent Light Source II (LCLS-II) will be shipped to SLAC (Menlo Park, California) from JLab (Newport News, Virginia) and FNAL (Batavia, Illinois). A transportation system has been designed and built to safely transport the CMs over the road. It uses an array of helical isolator springs to attenuate shocks on the CM to below 1.5g in all directions. The system rides on trailers equipped with Air-Ride suspension, which attenuates vibration loads. The prototype LCLS-II CM (pCM) was driven 750 miles to test the transport system; shock loggers recorded the shock attenuation on the pCM and vacuum gauges were used to detect any compromises in beamline vacuum. Alignment measurements were taken before and after the trip to check whether cavity positions had shifted beyond the ± 0.2mm spec. Passband frequencies and cavity gradients were measured at 2K at the Cryomodule Test Facility (CMTF) at JLab to identify any degradation of CM performance after transportation. The transport system was found to have safely carried the CM and is cleared to begin shipments from JLab and FNAL to SLAC.

Testing of a Transport Cask for Research Reactor Spent Fuel - 13003

International Nuclear Information System (INIS)

Mourao, Rogerio P.; Leite da Silva, Luiz; Miranda, Carlos A.; Mattar Neto, Miguel; Quintana, Jose F.A.; Saliba, Roberto O.; Novara, Oscar E.

2013-01-01

Since the beginning of the last decade three Latin American countries that operate research reactors - Argentina, Brazil and Chile - have been joining efforts to improve the regional capability in the management of spent fuel elements from the TRIGA and MTR reactors operated in the region. A main drive in this initiative, sponsored by the International Atomic Energy Agency, is the fact that no definite solution regarding the back end of the research reactor fuel cycle has been taken by any of the participating country. However, any long-term solution - either disposition in a repository or storage away from reactor - will involve at some stage the transportation of the spent fuel through public roads. Therefore, a licensed cask that provides adequate shielding, assurance of subcriticality, and conformance to internationally accepted safety, security and safeguards regimes is considered a strategic part of any future solution to be adopted at a regional level. As a step in this direction, a packaging for the transport of irradiated fuel for MTR and TRIGA research reactors was designed by the tri-national team and a half-scale model equipped with the MTR version of the internal basket was constructed in Argentina and Brazil and tested in Brazil. Three test campaigns have been carried out so far, covering both normal conditions of transportation and hypothetical accident conditions. After failing the tests in the first two test series, the specimen successfully underwent the last test sequence. A second specimen, incorporating the structural improvements in view of the previous tests results, will be tested in the near future. Numerical simulations of the free drop and thermal tests are being carried out in parallel, in order to validate the computational modeling that is going to be used as a support for the package certification. (authors)

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

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

Assessment of hydrologic transport of radionuclides from the Rio Blanco underground nuclear test site, Colorado

International Nuclear Information System (INIS)

Chapman, J.; Earman, S.; Andricevic, R.

1996-10-01

DOE is operating an environmental restoration program to characterize, remediate, and close non-Nevada Test Site locations used for nuclear testing. Evaluation of radionuclide transport by groundwater is part of preliminary risk analysis. These evaluations allow prioritization of test areas in terms of risk, provide a basis for discussions with regulators and the public about future work, and provide a framework for assessing site characterization data needs. The Rio Blanco site in Colorado was the location of the simultaneous detonation of three 30-kiloton nuclear devices. The devices were located 1780, 1899, and 2039 below ground surface in the Fort Union and Mesaverde formations. Although all the bedrock formations at the site are thought to contain water, those below the Green River Formation (below 1000 in depth) are also gas-bearing, and have very low permeabilities. The transport scenario evaluated was the migration of radionuclides from the blast-created cavity through the Fort Union Formation. Transport calculations were performed using the solute flux method, with input based on the limited data available for the site. Model results suggest that radionuclides from the test are contained entirely within the area currently administered by DOE. This modeling was performed to investigate how the uncertainty in various physical parameters affect radionuclide transport at the site, and to serve as a starting point for discussion regarding further investigation; it was not intended to be a definitive simulation of migration pathways or radionuclide concentration values. Given the sparse data, the modeling results may differ significantly from reality. Confidence in transport predictions can be increased by obtaining more site data, including the amount of radionuclides which would have been available for transport (i.e., not trapped in melt glass or vented during gas flow testing), and the hydraulic properties of the formation. 38 refs., 6 figs., 1 tab

A Fano cavity test for Monte Carlo proton transport algorithms

International Nuclear Information System (INIS)

Sterpin, Edmond; Sorriaux, Jefferson; Souris, Kevin; Vynckier, Stefaan; Bouchard, Hugo

2014-01-01

Purpose: In the scope of reference dosimetry of radiotherapy beams, Monte Carlo (MC) simulations are widely used to compute ionization chamber dose response accurately. Uncertainties related to the transport algorithm can be verified performing self-consistency tests, i.e., the so-called “Fano cavity test.” The Fano cavity test is based on the Fano theorem, which states that under charged particle equilibrium conditions, the charged particle fluence is independent of the mass density of the media as long as the cross-sections are uniform. Such tests have not been performed yet for MC codes simulating proton transport. The objectives of this study are to design a new Fano cavity test for proton MC and to implement the methodology in two MC codes: Geant4 and PENELOPE extended to protons (PENH). Methods: The new Fano test is designed to evaluate the accuracy of proton transport. Virtual particles with an energy ofE 0 and a mass macroscopic cross section of (Σ)/(ρ) are transported, having the ability to generate protons with kinetic energy E 0 and to be restored after each interaction, thus providing proton equilibrium. To perform the test, the authors use a simplified simulation model and rigorously demonstrate that the computed cavity dose per incident fluence must equal (ΣE 0 )/(ρ) , as expected in classic Fano tests. The implementation of the test is performed in Geant4 and PENH. The geometry used for testing is a 10 × 10 cm 2 parallel virtual field and a cavity (2 × 2 × 0.2 cm 3 size) in a water phantom with dimensions large enough to ensure proton equilibrium. Results: For conservative user-defined simulation parameters (leading to small step sizes), both Geant4 and PENH pass the Fano cavity test within 0.1%. However, differences of 0.6% and 0.7% were observed for PENH and Geant4, respectively, using larger step sizes. For PENH, the difference is attributed to the random-hinge method that introduces an artificial energy straggling if step size is not

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)

Sediment and radionuclide transport in rivers: radionuclide transport modeling for Cattaraugus and Buttermilk Creeks, New York

International Nuclear Information System (INIS)

Onishi, Y.; Yabusaki, S.B.; Kincaid, C.T.; Skaggs, R.L.; Walters, W.H.

1982-12-01

SERATRA, a transient, two-dimensional (laterally-averaged) computer model of sediment-contaminant transport in rivers, satisfactorily resolved the distribution of sediment and radionuclide concentrations in the Cattaraugus Creek stream system in New York. By modeling the physical processes of advection, diffusion, erosion, deposition, and bed armoring, SERATRA routed three sediment size fractions, including cohesive soils, to simulate three dynamic flow events. In conjunction with the sediment transport, SERATRA computed radionuclide levels in dissolved, suspended sediment, and bed sediment forms for four radionuclides ( 137 Cs, 90 Sr, 239 240 Pu, and 3 H). By accounting for time-dependent sediment-radionuclide interaction in the water column and bed, SERATA is a physically explicit model of radionuclide fate and migration. Sediment and radionuclide concentrations calculated by SERATA in the Cattaraugus Creek stream system are in reasonable agreement with measured values. SERATRA is in the field performance phase of an extensive testing program designed to establish the utility of the model as a site assessment tool. The model handles not only radionuclides but other contaminants such as pesticides, heavy metals and other toxic chemicals. Now that the model has been applied to four field sites, including the latest study of the Cattaraugus Creek stream system, it is recommended that a final model be validated through comparison of predicted results with field data from a carefully controlled tracer test at a field site. It is also recommended that a detailed laboratory flume be tested to study cohesive sediment transport, deposition, and erosion characteristics. The lack of current understanding of these characteristics is one of the weakest areas hindering the accurate assessment of the migration of radionuclides sorbed by fine sediments of silt and clay

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.

Test Report for Perforated Metal Air Transportable Package (PMATO) Prototype.

Energy Technology Data Exchange (ETDEWEB)

Bobbe, Jeffery G.; Pierce, Jim Dwight

2003-06-01

A prototype design for a plutonium air transport package capable of carrying 7.6 kg of plutonium oxide and surviving a ''worst-case'' plane crash has been developed by Sandia National Laboratories (SNL) for the Japan Nuclear Cycle Development Institute (JNC). A series of impact tests were conducted on half-scale models of this design for side, end, and comer orientations at speeds close to 282 m/s onto a target designed to simulate weathered sandstone. These tests were designed to evaluate the performance of the overpack concept and impact-limiting materials in critical impact orientations. The impact tests of the Perforated Metal Air Transportable Package (PMATP) prototypes were performed at SNL's 10,000-ft rocket sled track. This report describes test facilities calibration and environmental testing methods of the PMATP under specific test conditions. The tests were conducted according to the test plan and procedures that were written by the authors and approved by SNL management and quality assurance personnel. The result of these tests was that the half-scale PMATP survived the ''worst-case'' airplane crash conditions, and indicated that a full-scale PMATP, utilizing this overpack concept and these impact-limiting materials, would also survive these crash conditions.

Implementation and testing of a multivariate inverse radiation transport solver

International Nuclear Information System (INIS)

Mattingly, John; Mitchell, Dean J.

2012-01-01

Detection, identification, and characterization of special nuclear materials (SNM) all face the same basic challenge: to varying degrees, each must infer the presence, composition, and configuration of the SNM by analyzing a set of measured radiation signatures. Solutions to this problem implement inverse radiation transport methods. Given a set of measured radiation signatures, inverse radiation transport estimates properties of the source terms and transport media that are consistent with those signatures. This paper describes one implementation of a multivariate inverse radiation transport solver. The solver simultaneously analyzes gamma spectrometry and neutron multiplicity measurements to fit a one-dimensional radiation transport model with variable layer thicknesses using nonlinear regression. The solver's essential components are described, and its performance is illustrated by application to benchmark experiments conducted with plutonium metal. - Highlights: ► Inverse problems, specifically applied to identifying and characterizing radiation sources . ► Radiation transport. ► Analysis of gamma spectroscopy and neutron multiplicity counting measurements. ► Experimental testing of the inverse solver against measurements of plutonium.

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.

Neptunium Transport Behavior in the Vicinity of Underground Nuclear Tests at the Nevada Test Site

Energy Technology Data Exchange (ETDEWEB)

Zhao, P; Tinnacher, R M; Zavarin, M; Williams, R W; Kersting, A B

2010-12-03

We used short lived {sup 239}Np as a yield tracer and state of the art magnetic sector ICP-MS to measure ultra low levels of {sup 237}Np in a number of 'hot wells' at the Nevada National Security Site (NNSS), formerly known as the Nevada Test Site (NTS). The results indicate that {sup 237}Np concentrations at the Almendro, Cambric, Dalhart, Cheshire and Chancellor sites, are in the range of 3 x 10{sup -5} to 7 x 10{sup -2} pCi/L and well below the MCL for alpha emitting radionuclides (15 pCi/L) (EPA, 2009). Thus, while Np transport is believed to occur at the NNSS, activities are expected to be well below the regulatory limits for alpha-emitting radionuclides. We also compared {sup 237}Np concentration data to other radionuclides, including tritium, {sup 14}C, {sup 36}Cl, {sup 99}Tc, {sup 129}I, and plutonium, to evaluate the relative {sup 237}Np transport behavior. Based on isotope ratios relative to published unclassified Radiologic Source Terms (Bowen et al., 1999) and taking into consideration radionuclide distribution between melt glass, rubble and groundwater (IAEA, 1998), {sup 237}Np appears to be substantially less mobile than tritium and other non-sorbing radionuclides, as expected. However, this analysis also suggests that {sup 237}Np mobility is surprisingly similar to that of plutonium. The similar transport behavior of Np and Pu can be explained by one of two possibilities: (1) Np(IV) and Pu(IV) oxidation states dominate under mildly reducing NNSS groundwater conditions resulting in similar transport behavior or (2) apparent Np transport is the result of transport of its parent {sup 241}Pu and {sup 241}Am isotopes and subsequent decay to {sup 237}Np. Finally, measured {sup 237}Np concentrations were compared to recent Hydrologic Source Term (HST) models. The 237Np data collected from three wells in Frenchman Flat (RNM-1, RNM-2S, and UE-5n) are in good agreement with recent HST transport model predictions (Carle et al., 2005). The agreement

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

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.

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

Conceptual model for transport processes in the Culebra Dolomite Member, Rustler Formation

International Nuclear Information System (INIS)

Holt, R.M.

1997-08-01

The Culebra Dolomite Member of the Rustler Formation represents a possible pathway for contaminants from the Waste Isolation Pilot Plant underground repository to the accessible environment. The geologic character of the Culebra is consistent with a double-porosity, multiple-rate model for transport in which the medium is conceptualized as consisting of advective porosity, where solutes are carried by the groundwater flow, and fracture-bounded zones of diffusive porosity, where solutes move through slow advection or diffusion. As the advective travel length or travel time increases, the nature of transport within a double-porosity medium changes. This behavior is important for chemical sorption, because the specific surface area per unit mass of the diffusive porosity is much greater than in the advective porosity. Culebra transport experiments conducted at two different length scales show behavior consistent with a multiple-rate, double-porosity conceptual model for Culebra transport. Tracer tests conducted on intact core samples from the Culebra show no evidence of significant diffusion, suggesting that at the core scale the Culebra can be modeled as a single-porosity medium where only the advective porosity participates in transport. Field tracer tests conducted in the Culebra show strong double-porosity behavior that is best explained using a multiple-rate model

Development of Phenomenological Models of Underground Nuclear Tests on Pahute Mesa, Nevada Test Site - BENHAM and TYBO

Energy Technology Data Exchange (ETDEWEB)

Pawloski, G.A.

1999-09-21

Although it is well accepted that underground nuclear explosions modify the in situ geologic media around the explosion point, the details of these changes are neither well understood nor well documented. As part of the engineering and containment process before a nuclear test, the physical environment is characterized to some extent to predict how the explosion will interact with the in situ media. However, a more detailed characterization of the physical environment surrounding an expended site is needed to successfully model radionuclide transport in the groundwater away from the detonation point. It is important to understand how the media have been altered and where the radionuclides are deposited. Once understood, this information on modified geologic media can be incorporated into a phenomenological model that is suitable for input to computer simulations of groundwater flow and radionuclide transport. The primary goals of this study are to (1) identify the modification of the media at a pertinent scale, and (2) provide this information to researchers modeling radionuclide transport in groundwater for the US Department of Energy (DOE) Nevada Operations Office Underground Test Area (UGTA) Project. Results from this study are most applicable at near-field scale (a model domain of about 500 m) and intermediate-field scale (a model domain of about 5 km) for which detailed information can be maximized as it is incorporated in the modeling grids. UGTA collected data on radionuclides in groundwater during recent drilling at the ER-20-5 site, which is near BENHAM and TYBO on Pahute Mesa at the Nevada Test Site (NTS). Computer simulations are being performed to better understand radionuclide transport. The objectives of this modeling effort include: evaluating site-specific information from the BENHAM and TYBO tests on Pahute Mesa; augmenting the above data set with generalized containment data; and developing a phenomenological model suitable for input to

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)

MIGFRAC - a code for modelling of radionuclide transport in fracture media

International Nuclear Information System (INIS)

Satyanarayana, S.V.M.; Mohankumar, N.; Sasidhar, P.

2002-05-01

Radionuclides migrate through diffusion process from radioactive waste disposal facilities into fractures present in the host rock. The transport phenomenon is aided by the circulating ground waters. To model the transport of radionuclides in the charnockite rock formations present at Kalpakkam, a numerical code - MIGFRAC has been developed at SHINE Group, IGCAR. The code has been subjected to rigorous tests and the results of the build up of radionuclide concentrations are validated with a test case up to a distance of 100 meter along the fracture. The report discusses the model, code features and the results obtained up to a distance of 400 meter are presented. (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

9 m side drop test of scale model

International Nuclear Information System (INIS)

Ku, Jeong-Hoe; Chung, Seong-Hwan; Lee, Ju-Chan; Seo, Ki-Seog

1993-01-01

A type B(U) shipping cask had been developed in KAERI for transporting PWR spent fuel. Since the cask is to transport spent PWR fuel, it must be designed to meet all of the structural requirements specified in domestic packaging regulations and IAEA safety series No.6. This paper describes the side drop testing of a one - third scale model cask. The crush and deformations of the shock absorbing covers directly control the deceleration experiences of the cask during the 9 m side drop impact. The shock absorbing covers greatly mitigated the inertia forces of the cask body due to the side drop impact. Compared with the side drop test and finite element analysis, it was verified that the 1/3 scale model cask maintain its structural integrity of the model cask under the side drop impact. The test and analysis results could be used as the basic data to evaluate the structural integrity of the real cask. (J.P.N.)

Simulation of reactive geochemical transport in groundwater using a semi-analytical screening model

Science.gov (United States)

McNab, Walt W.

1997-10-01

A reactive geochemical transport model, based on a semi-analytical solution to the advective-dispersive transport equation in two dimensions, is developed as a screening tool for evaluating the impact of reactive contaminants on aquifer hydrogeochemistry. Because the model utilizes an analytical solution to the transport equation, it is less computationally intensive than models based on numerical transport schemes, is faster, and it is not subject to numerical dispersion effects. Although the assumptions used to construct the model preclude consideration of reactions between the aqueous and solid phases, thermodynamic mineral saturation indices are calculated to provide qualitative insight into such reactions. Test problems involving acid mine drainage and hydrocarbon biodegradation signatures illustrate the utility of the model in simulating essential hydrogeochemical phenomena.

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)

Extended numerical modeling of impurity neoclassical transport in tokamak edge plasmas

International Nuclear Information System (INIS)

Inoue, H.; Yamoto, S.; Hatayama, A.; Homma, Y.

2016-01-01

Understanding of impurity transport in tokamaks is an important issue in order to reduce the impurity contamination in fusion core plasmas. Recently, a new kinetic numerical scheme of impurity classical/neoclassical transport has been developed. This numerical scheme makes it possible to include classical self-diffusion (CL SD), classical inward pinch (CL IWP), and classical temperature screening effect (CL TSE) of impurity ions. However, impurity neoclassical transport has been modeled only in the case where background plasmas are in the Pfirsch-Schluter (PS) regime. The purpose of this study is to extend our previous model to wider range of collisionality regimes, i.e., not only the PS regime, but also the plateau regime. As in the previous study, a kinetic model with Binary Collision Monte-Carlo Model (BMC) has been adopted. We focus on the modeling of the neoclassical self-diffusion (NC SD) and the neoclassical inward pinch (NC IWP). In order to simulate the neoclassical transport with the BCM, velocity distribution of background plasma ions has been modeled as a deformed Maxwell distribution which includes plasma density gradient. Some test simulations have been done. As for NC SD of impurity ions, our scheme reproduces the dependence on the collisionality parameter in wide range of collisionality regime. As for NC IWP, in cases where test impurity ions and background ions are in the PS and plateau regimes, parameter dependences have been reproduced. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Extended numerical modeling of impurity neoclassical transport in tokamak edge plasmas

Energy Technology Data Exchange (ETDEWEB)

Inoue, H.; Yamoto, S.; Hatayama, A. [Graduate School of Science and Technology, Keio University, Hiyoshi, Yokohama (Japan); Homma, Y. [Graduate School of Science and Technology, Keio University, Hiyoshi, Yokohama (Japan); Research Fellow of Japan Society for the Promotion of Science, Tokyo (Japan)

2016-08-15

Understanding of impurity transport in tokamaks is an important issue in order to reduce the impurity contamination in fusion core plasmas. Recently, a new kinetic numerical scheme of impurity classical/neoclassical transport has been developed. This numerical scheme makes it possible to include classical self-diffusion (CL SD), classical inward pinch (CL IWP), and classical temperature screening effect (CL TSE) of impurity ions. However, impurity neoclassical transport has been modeled only in the case where background plasmas are in the Pfirsch-Schluter (PS) regime. The purpose of this study is to extend our previous model to wider range of collisionality regimes, i.e., not only the PS regime, but also the plateau regime. As in the previous study, a kinetic model with Binary Collision Monte-Carlo Model (BMC) has been adopted. We focus on the modeling of the neoclassical self-diffusion (NC SD) and the neoclassical inward pinch (NC IWP). In order to simulate the neoclassical transport with the BCM, velocity distribution of background plasma ions has been modeled as a deformed Maxwell distribution which includes plasma density gradient. Some test simulations have been done. As for NC SD of impurity ions, our scheme reproduces the dependence on the collisionality parameter in wide range of collisionality regime. As for NC IWP, in cases where test impurity ions and background ions are in the PS and plateau regimes, parameter dependences have been reproduced. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

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)

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

Directory of Open Access Journals (Sweden)

J. Brandt

2002-01-01

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

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

The effects of transport by car on coagulation tests.

Science.gov (United States)

Ergin, Merve; Erdogan, Serpil; Akturk, Onur; Erel, Ozcan

2017-10-26

This research investigated the effects of the transport of blood samples between centers/laboratories by car on coagulation tests. Five tubes of blood samples were taken from 20 healthy volunteers. The samples consisted of a baseline (control) group, centrifuged and noncentrifuged transported samples; centrifuged and noncentrifuged untransported samples. The groups of centrifuged and noncentrifuged samples were transported by car for 2 h. The centrifuged and noncentrifuged untransported samples were incubated in the laboratory until the transported samples arrived. Prothrombin time (PT) and activated partial thromboplastin time (APTT) tests were conducted for all samples. Significant differences between the baseline group and the centrifuged and noncentrifuged transported samples and the noncentrifuged untransported samples were found for APTT levels (pcar.

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.

Physical modelling and testing in environmental geotechnics

Energy Technology Data Exchange (ETDEWEB)

Garnier, J.; Thorel, L.; Haza, E. [Laboratoire Central des Ponts et Chaussees a Nantes, 44 - Nantes (France)

2000-07-01

The preservation of natural environment has become a major concern, which affects nowadays a wide range of professionals from local communities administrators to natural resources managers (water, wildlife, flora, etc) and, in the end, to the consumers that we all are. Although totally ignored some fifty years ago, environmental geotechnics has become an emergent area of study and research which borders on the traditional domains, with which the geo-technicians are confronted (soil and rock mechanics, engineering geology, natural and anthropogenic risk management). Dedicated to experimental approaches (in-situ investigations and tests, laboratory tests, small-scale model testing), the Symposium fits in with the geotechnical domains of environment and transport of soil pollutants. These proceedings report some progress of developments in measurement techniques and studies of transport of pollutants in saturated and unsaturated soils in order to improve our understanding of such phenomena within multiphase environments. Experimental investigations on decontamination and isolation methods for polluted soils are discussed. The intention is to assess the impact of in-situ and laboratory tests, as well as small-scale model testing, on engineering practice. One paper has been analyzed in INIS data base for its specific interest in nuclear industry.

Testing the effects of in-stream sediment sources and sinks on simulated watershed sediment yield using the coupled U.S. Army Corps of Engineers GSSHA Model and SEDLIB Sediment Transport Library

Science.gov (United States)

Floyd, I. E.; Downer, C. W.; Brown, G.; Pradhan, N. R.

2017-12-01

The Gridded Surface Subsurface Hydrologic Analysis (GSSHA) model is the US Army Corps of Engineers' (USACE)'s only fully coupled overland/in-stream sediment transport model. While the overland sediment transport formulation in GSSHA is considered state of the art, the existing in-stream sediment transport formulation is less robust. A major omission in the formulation of the existing GSSHA in-stream model is the lack of in-stream sources of fine materials. In this effort, we enhanced the in-stream sediment transport capacity of GSSHA by linking GSSHA to the SEDLIB sediment transport library. SEDLIB was developed at the Coastal and Hydraulics Laboratory (CHL) under the System Wide Water Resources Program (SWWRP) and Flood and Coastal (F&C) research program. It is designed to provide a library of sediment flux formulations for hydraulic and hydrologic models, such as GSSHA. This new version of GSSHA, with the updated in-stream sediment transport simulation capability afforded by the linkage to SEDLIB, was tested in against observations in an experimental watershed that had previously been used as a test bed for GSSHA. The results show a significant improvement in the ability to model in-stream sources of fine sediment. This improved capability will broaden the applicability of GSSHA to larger watersheds and watersheds with complex sediment dynamics, such as those subjected to fire hydrology.

Radon transport modelling: User's guide to RnMod3d

DEFF Research Database (Denmark)

Andersen, Claus Erik

2000-01-01

RnMod3d is a numerical computer model of soil-gas and radon transport in porous media. It can be used, for example, to study radon entry from soil into houses in response to indoor-outdoor pressure differences or changes in atmospheric pressure. It canalso be used for flux calculations of radon...... decay, diffusion and advection of radon can be solved. Moisture is included in the model, and partitioning ofradon between air, water and soil grains (adsorption) is taken into account. Most parameters can change in time and space, and transport parameters (diffusivity and permeability) may...... be anisotropic. This guide includes benchmark tests based on simpleproblems with known solutions. RnMod3d has also been part of an international model intercomparison exercise based on more complicated problems without known solutions. All tests show that RnMod3d gives results of good quality....

Busted Butte Unsaturated Zone Transport Test: Fiscal Year 1998 Status Report Yucca Mountain Site Characterization Program Deliverable SPU85M4

International Nuclear Information System (INIS)

Bussod, G.Y.; Turin, H.J.; Lowry, W.E.

1999-01-01

This report describes the status of the Busted Butte Unsaturated Zone Transport Test (UZTT) and documents the progress of construction activities and site and laboratory characterization activities undertaken in fiscal year 1998. Also presented are predictive flow-and-transport simulations for Test Phases 1 and 2 of testing and the preliminary results and status of these test phases. Future anticipated results obtained from unsaturated-zone (UZ) transport testing in the Calico Hills Formation at Busted Butte are also discussed in view of their importance to performance assessment (PA) needs to build confidence in and reduce the uncertainty of site-scale flow-and-transport models and their abstractions for performance for license application. The principal objectives of the test are to address uncertainties associated with flow and transport in the UZ site-process models for Yucca Mountain, as identified by the PA working group in February 1997. These include but are not restricted to: (1) The effect of heterogeneities on flow and transport in unsaturated and partially saturated conditions in the Calico Hills Formation. In particular, the test aims to address issues relevant to fracture-matrix interactions and permeability contrast boundaries; (2) The migration behavior of colloids in fractured and unfractured Calico Hills rocks; (3) The validation through field testing of laboratory sorption experiments in unsaturated Calico Hills rocks; (4) The evaluation of the 3-D site-scale flow-and-transport process model (i.e., equivalent-continuum/dual-permeability/discrete-fracture-fault representations of flow and transport) used in the PA abstractions for license application; and (5) The effect of scaling from lab scale to field scale and site scale

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

Contaminant transport model validation: The Oak Ridge Reservation

International Nuclear Information System (INIS)

Lee, R.R.; Ketelle, R.H.

1988-09-01

In the complex geologic setting on the Oak Ridge Reservation, hydraulic conductivity is anisotropic and flow is strongly influenced by an extensive and largely discontinuous fracture network. Difficulties in describing and modeling the aquifer system prompted a study to obtain aquifer property data to be used in a groundwater flow model validation experiment. Characterization studies included the performance of an extensive suite of aquifer test within a 600-square-meter area to obtain aquifer property values to describe the flow field in detail. Following aquifer test, a groundwater tracer test was performed under ambient conditions to verify the aquifer analysis. Tracer migration data in the near-field were used in model calibration to predict tracer arrival time and concentration in the far-field. Despite the extensive aquifer testing, initial modeling inaccurately predicted tracer migration direction. Initial tracer migration rates were consistent with those predicted by the model; however, changing environmental conditions resulted in an unanticipated decay in tracer movement. Evaluation of the predictive accuracy of groundwater flow and contaminant transport models on the Oak Ridge Reservation depends on defining the resolution required, followed by field testing and model grid definition at compatible scales. The use of tracer tests, both as a characterization method and to verify model results, provides the highest level of resolution of groundwater flow characteristics. 3 refs., 4 figs

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

Directory of Open Access Journals (Sweden)

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

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

Variable amplitude fatigue, modelling and testing

International Nuclear Information System (INIS)

Svensson, Thomas.

1993-01-01

Problems related to metal fatigue modelling and testing are here treated in four different papers. In the first paper different views of the subject are summarised in a literature survey. In the second paper a new model for fatigue life is investigated. Experimental results are established which are promising for further development of the mode. In the third paper a method is presented that generates a stochastic process, suitable to fatigue testing. The process is designed in order to resemble certain fatigue related features in service life processes. In the fourth paper fatigue problems in transport vibrations are treated

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.

Statistical atmospheric inversion of local gas emissions by coupling the tracer release technique and local-scale transport modelling: a test case with controlled methane emissions

Directory of Open Access Journals (Sweden)

S. Ars

2017-12-01

Full Text Available This study presents a new concept for estimating the pollutant emission rates of a site and its main facilities using a series of atmospheric measurements across the pollutant plumes. This concept combines the tracer release method, local-scale atmospheric transport modelling and a statistical atmospheric inversion approach. The conversion between the controlled emission and the measured atmospheric concentrations of the released tracer across the plume places valuable constraints on the atmospheric transport. This is used to optimise the configuration of the transport model parameters and the model uncertainty statistics in the inversion system. The emission rates of all sources are then inverted to optimise the match between the concentrations simulated with the transport model and the pollutants' measured atmospheric concentrations, accounting for the transport model uncertainty. In principle, by using atmospheric transport modelling, this concept does not strongly rely on the good colocation between the tracer and pollutant sources and can be used to monitor multiple sources within a single site, unlike the classical tracer release technique. The statistical inversion framework and the use of the tracer data for the configuration of the transport and inversion modelling systems should ensure that the transport modelling errors are correctly handled in the source estimation. The potential of this new concept is evaluated with a relatively simple practical implementation based on a Gaussian plume model and a series of inversions of controlled methane point sources using acetylene as a tracer gas. The experimental conditions are chosen so that they are suitable for the use of a Gaussian plume model to simulate the atmospheric transport. In these experiments, different configurations of methane and acetylene point source locations are tested to assess the efficiency of the method in comparison to the classic tracer release technique in coping

Statistical atmospheric inversion of local gas emissions by coupling the tracer release technique and local-scale transport modelling: a test case with controlled methane emissions

Science.gov (United States)

Ars, Sébastien; Broquet, Grégoire; Yver Kwok, Camille; Roustan, Yelva; Wu, Lin; Arzoumanian, Emmanuel; Bousquet, Philippe

2017-12-01

This study presents a new concept for estimating the pollutant emission rates of a site and its main facilities using a series of atmospheric measurements across the pollutant plumes. This concept combines the tracer release method, local-scale atmospheric transport modelling and a statistical atmospheric inversion approach. The conversion between the controlled emission and the measured atmospheric concentrations of the released tracer across the plume places valuable constraints on the atmospheric transport. This is used to optimise the configuration of the transport model parameters and the model uncertainty statistics in the inversion system. The emission rates of all sources are then inverted to optimise the match between the concentrations simulated with the transport model and the pollutants' measured atmospheric concentrations, accounting for the transport model uncertainty. In principle, by using atmospheric transport modelling, this concept does not strongly rely on the good colocation between the tracer and pollutant sources and can be used to monitor multiple sources within a single site, unlike the classical tracer release technique. The statistical inversion framework and the use of the tracer data for the configuration of the transport and inversion modelling systems should ensure that the transport modelling errors are correctly handled in the source estimation. The potential of this new concept is evaluated with a relatively simple practical implementation based on a Gaussian plume model and a series of inversions of controlled methane point sources using acetylene as a tracer gas. The experimental conditions are chosen so that they are suitable for the use of a Gaussian plume model to simulate the atmospheric transport. In these experiments, different configurations of methane and acetylene point source locations are tested to assess the efficiency of the method in comparison to the classic tracer release technique in coping with the distances

Safety Evaluation of Radioactive Material Transport Package under Stacking Test Condition

International Nuclear Information System (INIS)

Lee, Ju Chan; Seo, Ki Seog; Yoo, Seong Yeon

2012-01-01

Radioactive waste transport package was developed to transport eight drums of low and intermediate level waste(LILW) in accordance with the IAEA and domestic related regulations. The package is classified with industrial package IP-2. IP-2 package is required to undergo a free drop test and a stacking test. After free drop and stacking tests, it should prevent the loss or dispersal of radioactive contents, and loss of shielding integrity which would result in more than 20 % increase in the radiation level at any external surface of the package. The objective of this study is to establish the safety test method and procedure for stacking test and to prove the structural integrities of the IP-2 package. Stacking test and analysis were performed with a compressive load equal to five times the weight of the package for a period of 24 hours using a full scale model. Strains and displacements were measured at the corner fitting of the package during the stacking test. The measured strains and displacements were compared with the analysis results, and there were good agreements. It is very difficult to measure the deflection at the container base, so the maximum deflection of the container base was calculated by the analysis method. The maximum displacement at the corner fitting and deflection at the container base were less than their allowable values. Dimensions of the test model, thickness of shielding material and bolt torque were measured before and after the stacking test. Throughout the stacking test, it was found that there were no loss or dispersal of radioactive contents and no loss of shielding integrity. Thus, the package was shown to comply with the requirements to maintain structural integrity under the stacking condition.

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.

Tracer water transport and subgrid precipitation variation within atmospheric general circulation models

Science.gov (United States)

Koster, Randal D.; Eagleson, Peter S.; Broecker, Wallace S.

1988-03-01

A capability is developed for monitoring tracer water movement in the three-dimensional Goddard Institute for Space Science Atmospheric General Circulation Model (GCM). A typical experiment with the tracer water model follows water evaporating from selected grid squares and determines where this water first returns to the Earth's surface as precipitation or condensate, thereby providing information on the lateral scales of hydrological transport in the GCM. Through a comparison of model results with observations in nature, inferences can be drawn concerning real world water transport. Tests of the tracer water model include a comparison of simulated and observed vertically-integrated vapor flux fields and simulations of atomic tritium transport from the stratosphere to the oceans. The inter-annual variability of the tracer water model results is also examined.

Tracer water transport and subgrid precipitation variation within atmospheric general circulation models

Science.gov (United States)

Koster, Randal D.; Eagleson, Peter S.; Broecker, Wallace S.

1988-01-01

A capability is developed for monitoring tracer water movement in the three-dimensional Goddard Institute for Space Science Atmospheric General Circulation Model (GCM). A typical experiment with the tracer water model follows water evaporating from selected grid squares and determines where this water first returns to the Earth's surface as precipitation or condensate, thereby providing information on the lateral scales of hydrological transport in the GCM. Through a comparison of model results with observations in nature, inferences can be drawn concerning real world water transport. Tests of the tracer water model include a comparison of simulated and observed vertically-integrated vapor flux fields and simulations of atomic tritium transport from the stratosphere to the oceans. The inter-annual variability of the tracer water model results is also examined.

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

Modeling variably saturated multispecies reactive groundwater solute transport with MODFLOW-UZF and RT3D

Science.gov (United States)

Bailey, Ryan T.; Morway, Eric D.; Niswonger, Richard G.; Gates, Timothy K.

2013-01-01

A numerical model was developed that is capable of simulating multispecies reactive solute transport in variably saturated porous media. This model consists of a modified version of the reactive transport model RT3D (Reactive Transport in 3 Dimensions) that is linked to the Unsaturated-Zone Flow (UZF1) package and MODFLOW. Referred to as UZF-RT3D, the model is tested against published analytical benchmarks as well as other published contaminant transport models, including HYDRUS-1D, VS2DT, and SUTRA, and the coupled flow and transport modeling system of CATHY and TRAN3D. Comparisons in one-dimensional, two-dimensional, and three-dimensional variably saturated systems are explored. While several test cases are included to verify the correct implementation of variably saturated transport in UZF-RT3D, other cases are included to demonstrate the usefulness of the code in terms of model run-time and handling the reaction kinetics of multiple interacting species in variably saturated subsurface systems. As UZF1 relies on a kinematic-wave approximation for unsaturated flow that neglects the diffusive terms in Richards equation, UZF-RT3D can be used for large-scale aquifer systems for which the UZF1 formulation is reasonable, that is, capillary-pressure gradients can be neglected and soil parameters can be treated as homogeneous. Decreased model run-time and the ability to include site-specific chemical species and chemical reactions make UZF-RT3D an attractive model for efficient simulation of multispecies reactive transport in variably saturated large-scale subsurface systems.

Design and tests of a package for the transport of radioactive sources

International Nuclear Information System (INIS)

Santos, Paulo de Oliveira

2011-01-01

The Type A package was designed for transportation of seven cobalt-60 sources with total activity of 1 GBq. The shield thickness to accomplish the dose rate and the transport index established by the radioactive transport regulation was calculated by the code MCNP (Monte Carlo N-Particle Transport Code Version 5). The sealed cobalt-60 sources were tested for leakages. according to the regulation ISO 9978:1992 (E). The package was tested according to regulation Radioactive Material Transport CNEN. The leakage tests results pf the sources, and the package tests demonstrate that the transport can be safe performed from the CDTN to the steelmaking industries

MODEL CAR TRANSPORT SYSTEM - MODERN ITS EDUCATION TOOL

Directory of Open Access Journals (Sweden)

Karel Bouchner

2017-12-01

Full Text Available The model car transport system is a laboratory intended for a practical development in the area of the motor traffic. It is also an important education tool for students’ hands-on training, enabling students to test the results of their own studies. The main part of the model car transportation network is a model in a ratio 1:87 (HO, based on component units of FALLER Car system, e.g. cars, traffic lights, carriage way, parking spaces, stop sections, branch-off junctions, sensors and control sections. The model enables to simulate real traffic situations. It includes a motor traffic in a city, in a small village, on a carriageway between a city and a village including a railway crossing. The traffic infrastructure includes different kinds of intersections, such as T-junctions, a classic four-way crossroad and four-way traffic circle, with and without traffic lights control. Another important part of the model is a segment of a highway which includes an elevated crossing with highway approaches and exits.

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 VOC transport in simulated waste drums

International Nuclear Information System (INIS)

Liekhus, K.J.; Gresham, G.L.; Peterson, E.S.; Rae, C.; Hotz, N.J.; Connolly, M.J.

1993-06-01

A volatile organic compound (VOC) transport model has been developed to describe unsteady-state VOC permeation and diffusion within a waste drum. Model equations account for three primary mechanisms for VOC transport from a void volume within the drum. These mechanisms are VOC permeation across a polymer boundary, VOC diffusion across an opening in a volume boundary, and VOC solubilization in a polymer boundary. A series of lab-scale experiments was performed in which the VOC concentration was measured in simulated waste drums under different conditions. A lab-scale simulated waste drum consisted of a sized-down 55-gal metal drum containing a modified rigid polyethylene drum liner. Four polyethylene bags were sealed inside a large polyethylene bag, supported by a wire cage, and placed inside the drum liner. The small bags were filled with VOC-air gas mixture and the VOC concentration was measured throughout the drum over a period of time. Test variables included the type of VOC-air gas mixtures introduced into the small bags, the small bag closure type, and the presence or absence of a variable external heat source. Model results were calculated for those trials where the VOC permeability had been measured. Permeabilities for five VOCs [methylene chloride, 1,1,2-trichloro-1,2,2-trifluoroethane (Freon-113), 1,1,1-trichloroethane, carbon tetrachloride, and trichloroethylene] were measured across a polyethylene bag. Comparison of model and experimental results of VOC concentration as a function of time indicate that model accurately accounts for significant VOC transport mechanisms in a lab-scale waste drum

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 tritium transport in the environment

International Nuclear Information System (INIS)

Murphy, C.E. Jr.

1986-01-01

A model of tritium transport in the environment near an atmospheric source of tritium is presented in the general context of modeling material cycling in ecosystems. The model was developed to test hypotheses about the process involved in tritium cycling. The temporal and spatial scales of the model were picked to allow comparison to environmental monitoring data collected in the vicinity of the Savannah River Plant. Initial simulations with the model showed good agreement with monitoring data, including atmospheric and vegetation tritium concentrations. The model can also simulate values of tritium in vegetation organic matter if the key parameter distributing the source of organic hydrogen is varied to fit the data. However, because of the lack of independent conformation of the distribution parameter, there is still uncertainty about the role of organic movement of tritium in the food chain, and its effect on the dose to man

Automatic modeling for the Monte Carlo transport code Geant4

International Nuclear Information System (INIS)

Nie Fanzhi; Hu Liqin; Wang Guozhong; Wang Dianxi; Wu Yican; Wang Dong; Long Pengcheng; FDS Team

2015-01-01

Geant4 is a widely used Monte Carlo transport simulation package. Its geometry models could be described in Geometry Description Markup Language (GDML), but it is time-consuming and error-prone to describe the geometry models manually. This study implemented the conversion between computer-aided design (CAD) geometry models and GDML models. This method has been Studied based on Multi-Physics Coupling Analysis Modeling Program (MCAM). The tests, including FDS-Ⅱ model, demonstrated its accuracy and feasibility. (authors)

Design of an intermediate-scale experiment to validate unsaturated- zone transport models

International Nuclear Information System (INIS)

Siegel, M.D.; Hopkins, P.L.; Glass, R.J.; Ward, D.B.

1991-01-01

An intermediate-scale experiment is being carried out to evaluate instrumentation and models that might be used for transport-model validation for the Yucca Mountain Site Characterization Project. The experimental test bed is a 6-m high x 3-m diameter caisson filled with quartz sand with a sorbing layer at an intermediate depth. The experiment involves the detection and prediction of the migration of fluid and tracers through an unsaturated porous medium. Pre-test design requires estimation of physical properties of the porous medium such as the relative permeability, saturation/pressure relations, porosity, and saturated hydraulic conductivity as well as geochemical properties such as surface complexation constants and empircial K d 'S. The pre-test characterization data will be used as input to several computer codes to predict the fluid flow and tracer migration. These include a coupled chemical-reaction/transport model, a stochastic model, and a deterministic model using retardation factors. The calculations will be completed prior to elution of the tracers, providing a basis for validation by comparing the predictions to observed moisture and tracer behavior

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

Lab-scale tests on ISV vapor transport phenomena

International Nuclear Information System (INIS)

Farnsworth, R.K.; Gardner, B.M.

1996-01-01

In situ vitrification (ISV) is a promising technology for remediating buried waste sites and contaminated soil sites. However, concerns exist that low soil permeabilities may limit vapor transport away from the advancing melt front and cause a melt expulsion that breaches ISV containment. As a result, two ISV lab tests were conducted at the Idaho National Engineering Laboratory (INEL) using INEL soil (permeability: 10 -6 cm/s) and a low permeability (10 -10 cm/s) clay material. The clay test also had a ceramic tube inserted vertically through the center of the area being melted to provide one-dimensional data on vapor transport. Results confirm that low soil permeabilities can limit vapor transport away from the advancing ISV melt front. In addition, peak pressures inside the ceramic tube were significantly greater than those outside the tube, indicating the importance of horizontal vapor transport around the advancing ISV melt front

Physical modelling and testing in environmental geotechnics

International Nuclear Information System (INIS)

Garnier, J.; Thorel, L.; Haza, E.

2000-01-01

The preservation of natural environment has become a major concern, which affects nowadays a wide range of professionals from local communities administrators to natural resources managers (water, wildlife, flora, etc) and, in the end, to the consumers that we all are. Although totally ignored some fifty years ago, environmental geotechnics has become an emergent area of study and research which borders on the traditional domains, with which the geo-technicians are confronted (soil and rock mechanics, engineering geology, natural and anthropogenic risk management). Dedicated to experimental approaches (in-situ investigations and tests, laboratory tests, small-scale model testing), the Symposium fits in with the geotechnical domains of environment and transport of soil pollutants. These proceedings report some progress of developments in measurement techniques and studies of transport of pollutants in saturated and unsaturated soils in order to improve our understanding of such phenomena within multiphase environments. Experimental investigations on decontamination and isolation methods for polluted soils are discussed. The intention is to assess the impact of in-situ and laboratory tests, as well as small-scale model testing, on engineering practice. One paper is analysed in INIS data base for its specific interest in nuclear industry. The other ones, concerning the energy, are analyzed in ETDE data base

Metallic insulation transport and strainer clogging tests

International Nuclear Information System (INIS)

Hyvaerinen, J.; Hongisto, O.

1994-06-01

Experiments to probe the transport and clogging properties of metallic (metal reflective) insulation have been carried out in order to provide data for evaluation of their influence on the emergency core cooling and containment spray systems of the Finnish boiling water reactors in the event of a design basis accident. The specific metallic insulation tested was DARMET, provided by Darchem Engineering Ltd. The inner foils of Darmet are dimped. Available literature on the metallic insulation performance under design basis accident conditions has been reviewed. On the basis of the review a parametric approach has been chosen for the transport and clogging experiments. This approach involves testing a wide size range of various shapes of foil pieces. Five sets of experiments have been carried out. The first three sets investigate transport properties of the foil pieces, starting from sedimentation in stagnant waste pool and proceeding to transport in horizontal and vertically circulating flows. The clogging experiments have been addressed the differential pressures obtained due to accumulation of both pure and metallic and a mixture of metallic and fibrous (mineral wool) depris. (4 refs., 24 figs., 2 tabs.)

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....

Gray and multigroup radiation transport models for two-dimensional binary stochastic media using effective opacities

International Nuclear Information System (INIS)

Olson, Gordon L.

2016-01-01

One-dimensional models for the transport of radiation through binary stochastic media do not work in multi-dimensions. Authors have attempted to modify or extend the 1D models to work in multidimensions without success. Analytic one-dimensional models are successful in 1D only when assuming greatly simplified physics. State of the art theories for stochastic media radiation transport do not address multi-dimensions and temperature-dependent physics coefficients. Here, the concept of effective opacities and effective heat capacities is found to well represent the ensemble averaged transport solutions in cases with gray or multigroup temperature-dependent opacities and constant or temperature-dependent heat capacities. In every case analyzed here, effective physics coefficients fit the transport solutions over a useful range of parameter space. The transport equation is solved with the spherical harmonics method with angle orders of n=1 and 5. Although the details depend on what order of solution is used, the general results are similar, independent of angular order. - Highlights: • Gray and multigroup radiation transport is done through 2D stochastic media. • Approximate models for the mean radiation field are found for all test problems. • Effective opacities are adjusted to fit the means of stochastic media transport. • Test problems include temperature dependent opacities and heat capacities • Transport solutions are done with angle orders n=1 and 5.

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

Modeling variably saturated subsurface solute transport with MODFLOW-UZF and MT3DMS

Science.gov (United States)

Morway, Eric D.; Niswonger, Richard G.; Langevin, Christian D.; Bailey, Ryan T.; Healy, Richard W.

2013-01-01

The MT3DMS groundwater solute transport model was modified to simulate solute transport in the unsaturated zone by incorporating the unsaturated-zone flow (UZF1) package developed for MODFLOW. The modified MT3DMS code uses a volume-averaged approach in which Lagrangian-based UZF1 fluid fluxes and storage changes are mapped onto a fixed grid. Referred to as UZF-MT3DMS, the linked model was tested against published benchmarks solved analytically as well as against other published codes, most frequently the U.S. Geological Survey's Variably-Saturated Two-Dimensional Flow and Transport Model. Results from a suite of test cases demonstrate that the modified code accurately simulates solute advection, dispersion, and reaction in the unsaturated zone. Two- and three-dimensional simulations also were investigated to ensure unsaturated-saturated zone interaction was simulated correctly. Because the UZF1 solution is analytical, large-scale flow and transport investigations can be performed free from the computational and data burdens required by numerical solutions to Richards' equation. Results demonstrate that significant simulation runtime savings can be achieved with UZF-MT3DMS, an important development when hundreds or thousands of model runs are required during parameter estimation and uncertainty analysis. Three-dimensional variably saturated flow and transport simulations revealed UZF-MT3DMS to have runtimes that are less than one tenth of the time required by models that rely on Richards' equation. Given its accuracy and efficiency, and the wide-spread use of both MODFLOW and MT3DMS, the added capability of unsaturated-zone transport in this familiar modeling framework stands to benefit a broad user-ship.

Modeling biogechemical reactive transport in a fracture zone

Energy Technology Data Exchange (ETDEWEB)

Molinero, Jorge; Samper, Javier; Yang, Chan Bing, and Zhang, Guoxiang; Guoxiang, Zhang

2005-01-14

A coupled model of groundwater flow, reactive solute transport and microbial processes for a fracture zone of the Aspo site at Sweden is presented. This is the model of the so-called Redox Zone Experiment aimed at evaluating the effects of tunnel construction on the geochemical conditions prevailing in a fracture granite. It is found that a model accounting for microbially-mediated geochemical processes is able to reproduce the unexpected measured increasing trends of dissolved sulfate and bicarbonate. The model is also useful for testing hypotheses regarding the role of microbial processes and evaluating the sensitivity of model results to changes in biochemical parameters.

Modeling biogeochemical reactive transport in a fracture zone

International Nuclear Information System (INIS)

Molinero, Jorge; Samper, Javier; Yang, Chan Bing; Zhang, Guoxiang; Guoxiang, Zhang

2005-01-01

A coupled model of groundwater flow, reactive solute transport and microbial processes for a fracture zone of the Aspo site at Sweden is presented. This is the model of the so-called Redox Zone Experiment aimed at evaluating the effects of tunnel construction on the geochemical conditions prevailing in a fracture granite. It is found that a model accounting for microbially-mediated geochemical processes is able to reproduce the unexpected measured increasing trends of dissolved sulfate and bicarbonate. The model is also useful for testing hypotheses regarding the role of microbial processes and evaluating the sensitivity of model results to changes in biochemical parameters

Transport Network Technologies – Study and Testing

DEFF Research Database (Denmark)

Bozorgebrahimi, K.; Channegowda, M.; Colmenero, A.

Following on from the theoretical research into Carrier Class Transport Network Technologies (CCTNTs) documented in DJ1.1.1, this report describes the extensive testing performed by JRA1 Task 1. The tests covered EoMPLS, Ethernet OAM, Synchronous Ethernet, PBB-TE, MPLS-TP, OTN and GMPLS...

Pressure distribution data from tests of 2.29 M (7.5 feet) span EET high-lift transport aircraft model in the Ames 12-foot pressure tunnel

Science.gov (United States)

Kjelgaard, S. O.; Morgan, H. L., Jr.

1983-01-01

A high-lift transport aircraft model equipped with full-span leading-edge slat and part-span double-slotted trailing-edge flap was tested in the Ames 12-ft pressure tunnel to determine the low-speed performance characteristics of a representative high-aspect-ratio supercritical wing. These tests were performed in support of the Energy Efficient Transport (EET) program which is one element of the Aircraft Energy Efficiency (ACEE) project. Static longitudinal forces and moments and chordwise pressure distributions at three spanwise stations were measured for cruise, climb, two take-off flap, and two landing flap wing configurations. The tabulated and plotted pressure distribution data is presented without analysis or discussion.

Cosmic-Ray Transport in Heliospheric Magnetic Structures. II. Modeling Particle Transport through Corotating Interaction Regions

Energy Technology Data Exchange (ETDEWEB)

Kopp, Andreas [Université Libre de Bruxelles, Service de Physique Statistique et des Plasmas, CP 231, B-1050 Brussels (Belgium); Wiengarten, Tobias; Fichtner, Horst [Institut für Theoretische Physik IV, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Effenberger, Frederic [Department of Physics and KIPAC, Stanford University, Stanford, CA 94305 (United States); Kühl, Patrick; Heber, Bernd [Institut für Experimentelle und Angewandte Physik, Christian-Albrecht-Universität zu Kiel, D-24098 Kiel (Germany); Raath, Jan-Louis; Potgieter, Marius S. [Centre for Space Research, North-West University, 2520 Potchefstroom (South Africa)

2017-03-01

The transport of cosmic rays (CRs) in the heliosphere is determined by the properties of the solar wind plasma. The heliospheric plasma environment has been probed by spacecraft for decades and provides a unique opportunity for testing transport theories. Of particular interest for the three-dimensional (3D) heliospheric CR transport are structures such as corotating interaction regions (CIRs), which, due to the enhancement of the magnetic field strength and magnetic fluctuations within and due to the associated shocks as well as stream interfaces, do influence the CR diffusion and drift. In a three-fold series of papers, we investigate these effects by modeling inner-heliospheric solar wind conditions with the numerical magnetohydrodynamic (MHD) framework Cronos (Wiengarten et al., referred as Paper I), and the results serve as input to a transport code employing a stochastic differential equation approach (this paper). While, in Paper I, we presented results from 3D simulations with Cronos, the MHD output is now taken as an input to the CR transport modeling. We discuss the diffusion and drift behavior of Galactic cosmic rays using the example of different theories, and study the effects of CIRs on these transport processes. In particular, we point out the wide range of possible particle fluxes at a given point in space resulting from these different theories. The restriction of this variety by fitting the numerical results to spacecraft data will be the subject of the third paper of this series.

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

INTRAVAL Phase 2: Modeling testing at the Las Cruces Trench Site

International Nuclear Information System (INIS)

Hills, R.G.; Rockhold, M.; Xiang, J.; Scanlon, B.; Wittmeyer, G.

1994-01-01

Several field experiments have been performed by scientists from the University of Arizona and New Mexico State University at the Las Cruces Trench Site to provide data tc test deterministic and stochastic models for water flow and solute transport. These experiments were performed in collaboration with INTRAVAL, an international effort toward validation of geosphere models for the transport of radionuclides. During Phase I of INTRAVAL, qualitative comparisons between experimental data and model predictions were made using contour plots of water contents and solute concentrations. Detailed quantitative comparisons were not made. To provide data for more rigorous model testing, a third Las Cruces Trench experiment was designed by scientists from the University of Arizona and New Mexico State University. Modelers from the Center for Nuclear Waste Regulatory Analysis, Massachusetts Institute of Technology, New Mexico State University, Pacific Northwest Laboratory, and the University of Texas provided predictions of water flow and tritium transport to New Mexico State University for analysis. The corresponding models assumed soil characterizations ranging from uniform to deterministically heterogeneous to stochastic. This report presents detailed quantitative comparisons to field data

Directory of transport packaging test facilities

International Nuclear Information System (INIS)

1983-08-01

Radioactive materials are transported in packagings or containers which have to withstand certain tests depending on whether they are Type A or Type B packagings. In answer to a request by the International Atomic Energy Agency, 13 Member States have provided information on the test facilities and services existing in their country which can be made available for use by other states by arrangement for testing different kinds of packagings. The directory gives the technical information on the facilities, the services, the tests that can be done and in some cases even the financial arrangement is included

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

Assessment of hydrologic transport of radionuclides from the Rulison Underground Nuclear Test Site, Colorado

International Nuclear Information System (INIS)

Earman, S.; Chapman, J.; Andricevic, R.

1996-09-01

The U.S. Department of Energy (DOE) is operating an environmental restoration program to characterize, remediate, and close non-Nevada Test Site locations that were used for nuclear testing. Evaluation of radionuclide transport by groundwater from these sites is an important part of the preliminary risk analysis. These evaluations are undertaken to allow prioritization of the test areas in terms of risk, provide a quantitative basis for discussions with regulators and the public about future work at the sites, and provide a framework for assessing data needs to be filled by site characterization. The Rulison site in west-central Colorado was the location of an underground detonation of a 40-kiloton nuclear device in 1969. The test took place 2,568 m below ground surface in the Mesaverde Formation. Though located below the regional water table, none of the bedrock formations at the site yielded water during hydraulic tests, indicating extremely low permeability conditions. The scenario evaluated was the migration of radionuclides from the blast-created cavity through the Mesaverde Formation. Transport calculations were performed using the solute flux method, with input based on the limited data available for the site. Model results suggest that radionuclides from the test are contained entirely within the area currently administered by DOE. The transport calculations are most sensitive to changes in the mean groundwater velocity and the correlation scale of hydraulic conductivity, with transport of strontium and cesium also sensitive to the sorption coefficient

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.

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.

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.

HMPT: Hazardous Waste Transportation Live 27928, Test 27929

Energy Technology Data Exchange (ETDEWEB)

Simpson, Lewis Edward [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-03-17

HMPT: Hazardous Waste Transportation (Live 27928, suggested one time and associated Test 27929, required initially and every 36 months) addresses the Department of Transportation (DOT) function-specific training requirements of the hazardous materials packagings and transportation (HMPT) Los Alamos National Laboratory (LANL) lab-wide training. This course addresses the requirements of the DOT that are unique to hazardous waste shipments. Appendix B provides the Title 40 Code of Federal Regulations (CFR) reference material needed for this course.

Comparison of low confinement mode transport simulations using the mixed Bohm/gyro-Bohm and the Multi-Mode-95 transport model

International Nuclear Information System (INIS)

Onjun, Thawatchai; Bateman, Glenn; Kritz, Arnold H.; Hannum, David

2001-01-01

Predictive transport simulations using the mixed Bohm/gyro-Bohm (JET) transport model [M. Erba , Plasma Phys. Controlled Fusion 39, 261 (1997)] are compared with simulations using the Multi-Mode-95 (MMM95) transport model [G. Bateman , Phys. Plasmas 5, 1793 (1998)]. Temperature and density profiles from these simulations are compared with experimental data for 13 low confinement mode (L-mode) discharges from the Doublet III-D Tokamak (DIII-D) [J. L. Luxon and L. G. Davis, Fusion Technol. 8, 441 (1985)] and the Tokamak Fusion Test Reactor (TFTR) [D. Grove and D. M. Meade, Nucl. Fusion 25, 1167 (1985)]. The selected discharges include systematic scans over gyro-radius, plasma power, current, and density. It is found that simulations using the two models match experimental data equally well, in spite of the fact that the JET model has predominantly Bohm scaling (proportional to gyro-radius) while the MMM95 model has a purely gyro-Bohm scaling (proportional to gyro-radius squared)

A time dependent mixing model to close PDF equations for transport in heterogeneous aquifers

Science.gov (United States)

Schüler, L.; Suciu, N.; Knabner, P.; Attinger, S.

2016-10-01

Probability density function (PDF) methods are a promising alternative to predicting the transport of solutes in groundwater under uncertainty. They make it possible to derive the evolution equations of the mean concentration and the concentration variance, used in moment methods. The mixing model, describing the transport of the PDF in concentration space, is essential for both methods. Finding a satisfactory mixing model is still an open question and due to the rather elaborate PDF methods, a difficult undertaking. Both the PDF equation and the concentration variance equation depend on the same mixing model. This connection is used to find and test an improved mixing model for the much easier to handle concentration variance. Subsequently, this mixing model is transferred to the PDF equation and tested. The newly proposed mixing model yields significantly improved results for both variance modelling and PDF modelling.

Representation of tropical deep convection in atmospheric models – Part 2: Tracer transport

Directory of Open Access Journals (Sweden)

C. R. Hoyle

2011-08-01

Full Text Available The tropical transport processes of 14 different models or model versions were compared, within the framework of the SCOUT-O3 (Stratospheric-Climate Links with Emphasis on the Upper Troposphere and Lower Stratosphere project. The tested models range from the regional to the global scale, and include numerical weather prediction (NWP, chemical transport, and chemistry-climate models. Idealised tracers were used in order to prevent the model's chemistry schemes from influencing the results substantially, so that the effects of modelled transport could be isolated. We find large differences in the vertical transport of very short-lived tracers (with a lifetime of 6 h within the tropical troposphere. Peak convective outflow altitudes range from around 300 hPa to almost 100 hPa among the different models, and the upper tropospheric tracer mixing ratios differ by up to an order of magnitude. The timing of convective events is found to be different between the models, even among those which source their forcing data from the same NWP model (ECMWF. The differences are less pronounced for longer lived tracers, however they could have implications for modelling the halogen burden of the lowermost stratosphere through transport of species such as bromoform, or short-lived hydrocarbons into the lowermost stratosphere. The modelled tracer profiles are strongly influenced by the convective transport parameterisations, and different boundary layer mixing parameterisations also have a large impact on the modelled tracer profiles. Preferential locations for rapid transport from the surface into the upper troposphere are similar in all models, and are mostly concentrated over the western Pacific, the Maritime Continent and the Indian Ocean. In contrast, models do not indicate that upward transport is highest over western Africa.

Finite element modeling of contaminant transport in soils including the effect of chemical reactions.

Science.gov (United States)

Javadi, A A; Al-Najjar, M M

2007-05-17

The movement of chemicals through soils to the groundwater is a major cause of degradation of water resources. In many cases, serious human and stock health implications are associated with this form of pollution. Recent studies have shown that the current models and methods are not able to adequately describe the leaching of nutrients through soils, often underestimating the risk of groundwater contamination by surface-applied chemicals, and overestimating the concentration of resident solutes. Furthermore, the effect of chemical reactions on the fate and transport of contaminants is not included in many of the existing numerical models for contaminant transport. In this paper a numerical model is presented for simulation of the flow of water and air and contaminant transport through unsaturated soils with the main focus being on the effects of chemical reactions. The governing equations of miscible contaminant transport including advection, dispersion-diffusion and adsorption effects together with the effect of chemical reactions are presented. The mathematical framework and the numerical implementation of the model are described in detail. The model is validated by application to a number of test cases from the literature and is then applied to the simulation of a physical model test involving transport of contaminants in a block of soil with particular reference to the effects of chemical reactions. Comparison of the results of the numerical model with the experimental results shows that the model is capable of predicting the effects of chemical reactions with very high accuracy. The importance of consideration of the effects of chemical reactions is highlighted.

Tritium transport calculations for the IFMIF Tritium Release Test Module

Energy Technology Data Exchange (ETDEWEB)

Freund, Jana, E-mail: jana.freund@kit.edu; Arbeiter, Frederik; Abou-Sena, Ali; Franza, Fabrizio; Kondo, Keitaro

2014-10-15

Highlights: • Delivery of material data for the tritium balance in the IFMIF Tritium Release Test Module. • Description of the topological models in TMAP and the adapted fusion-devoted Tritium Permeation Code (FUS-TPC). • Computation of release of tritium from the breeder solid material into the purge gas. • Computation of the loss of tritium over the capsule wall, rig hull, container wall and purge gas return line. - Abstract: The IFMIF Tritium Release Test Module (TRTM) is projected to measure online the tritium release from breeder ceramics and beryllium pebble beds under high energy neutron irradiation. Tritium produced in the pebble bed of TRTM is swept out continuously by a purge gas flow, but can also permeate into the module's metal structures, and can be lost by permeation to the environment. According analyses on the tritium inventory are performed to support IFMIF plant safety studies, and to support the experiment planning. This paper describes the necessary elements for calculation of the tritium transport in the Tritium Release Test Module as follows: (i) applied equations for the tritium balance, (ii) material data from literature and (iii) the topological models and the computation of the five different cases; namely release of tritium from the breeder solid material into the purge gas, loss of tritium over the capsule wall, rig hull, container wall and purge gas return line in detail. The problem of tritium transport in the TRTM has been studied and analyzed by the Tritium Migration Analysis Program (TMAP) and the adapted fusion-devoted Tritium Permeation Code (FUS-TPC). TMAP has been developed at INEEL and now exists in Version 7. FUS-TPC Code was written in MATLAB with the original purpose to study the tritium transport in Helium Cooled Lead Lithium (HCLL) blanket and in a later version the Helium Cooled Pebble Bed (HCPB) blanket by [6] (Franza, 2012). This code has been further modified to be applicable to the TRTM. Results from the

Tritium transport calculations for the IFMIF Tritium Release Test Module

International Nuclear Information System (INIS)

Freund, Jana; Arbeiter, Frederik; Abou-Sena, Ali; Franza, Fabrizio; Kondo, Keitaro

2014-01-01

Highlights: • Delivery of material data for the tritium balance in the IFMIF Tritium Release Test Module. • Description of the topological models in TMAP and the adapted fusion-devoted Tritium Permeation Code (FUS-TPC). • Computation of release of tritium from the breeder solid material into the purge gas. • Computation of the loss of tritium over the capsule wall, rig hull, container wall and purge gas return line. - Abstract: The IFMIF Tritium Release Test Module (TRTM) is projected to measure online the tritium release from breeder ceramics and beryllium pebble beds under high energy neutron irradiation. Tritium produced in the pebble bed of TRTM is swept out continuously by a purge gas flow, but can also permeate into the module's metal structures, and can be lost by permeation to the environment. According analyses on the tritium inventory are performed to support IFMIF plant safety studies, and to support the experiment planning. This paper describes the necessary elements for calculation of the tritium transport in the Tritium Release Test Module as follows: (i) applied equations for the tritium balance, (ii) material data from literature and (iii) the topological models and the computation of the five different cases; namely release of tritium from the breeder solid material into the purge gas, loss of tritium over the capsule wall, rig hull, container wall and purge gas return line in detail. The problem of tritium transport in the TRTM has been studied and analyzed by the Tritium Migration Analysis Program (TMAP) and the adapted fusion-devoted Tritium Permeation Code (FUS-TPC). TMAP has been developed at INEEL and now exists in Version 7. FUS-TPC Code was written in MATLAB with the original purpose to study the tritium transport in Helium Cooled Lead Lithium (HCLL) blanket and in a later version the Helium Cooled Pebble Bed (HCPB) blanket by [6] (Franza, 2012). This code has been further modified to be applicable to the TRTM. Results from 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

A fully resolved active musculo-mechanical model for esophageal transport

Science.gov (United States)

Kou, Wenjun; Bhalla, Amneet Pal Singh; Griffith, Boyce E.; Pandolfino, John E.; Kahrilas, Peter J.; Patankar, Neelesh A.

2015-10-01

Esophageal transport is a physiological process that mechanically transports an ingested food bolus from the pharynx to the stomach via the esophagus, a multi-layered muscular tube. This process involves interactions between the bolus, the esophagus, and the neurally coordinated activation of the esophageal muscles. In this work, we use an immersed boundary (IB) approach to simulate peristaltic transport in the esophagus. The bolus is treated as a viscous fluid that is actively transported by the muscular esophagus, and the esophagus is modeled as an actively contracting, fiber-reinforced tube. Before considering the full model of the esophagus, however, we first consider a standard benchmark problem of flow past a cylinder. Next a simplified version of our model is verified by comparison to an analytic solution to the tube dilation problem. Finally, three different complex models of the multi-layered esophagus, which differ in their activation patterns and the layouts of the mucosal layers, are extensively tested. To our knowledge, these simulations are the first of their kind to incorporate the bolus, the multi-layered esophagus tube, and muscle activation into an integrated model. Consistent with experimental observations, our simulations capture the pressure peak generated by the muscle activation pulse that travels along the bolus tail. These fully resolved simulations provide new insights into roles of the mucosal layers during bolus transport. In addition, the information on pressure and the kinematics of the esophageal wall resulting from the coordination of muscle activation is provided, which may help relate clinical data from manometry and ultrasound images to the underlying esophageal motor function.

Radiation transport analyses for IFMIF design by the Attila software using a Monte-Carlo source model

International Nuclear Information System (INIS)

Arter, W.; Loughlin, M.J.

2009-01-01

Accurate calculation of the neutron transport through the shielding of the IFMIF test cell, defined by CAD, is a difficult task for several reasons. The ability of the powerful deterministic radiation transport code Attila, to do this rapidly and reliably has been studied. Three models of increasing geometrical complexity were produced from the CAD using the CADfix software. A fourth model was produced to represent transport within the cell. The work also involved the conversion of the Vitenea-IEF database for high energy neutrons into a format usable by Attila, and the conversion of a particle source specified in MCNP wssaformat to a form usable by Attila. The final model encompassed the entire test cell environment, with only minor modifications. On a state-of-the-art PC, Attila took approximately 3 h to perform the calculations, as a consequence of a careful mesh 'layering'. The results strongly suggest that Attila will be a valuable tool for modelling radiation transport in IFMIF, and for similar problems

Characterization of Gas Transport Properties of Fractured Rocks By Borehole and Chamber Tests.

Science.gov (United States)

Shimo, M.; Shimaya, S.; Maejima, T.

2014-12-01

Gas transport characteristics of fractured rocks is a great concern to variety of engineering applications such as underground storage of LPG, nuclear waste disposal, CCS and gas flooding in the oil field. Besides absolute permeability, relative permeability and capillary pressure as a function of water saturation have direct influences to the results of two phase flow simulation. However, number of the reported gas flow tests for fractured rocks are limited, therefore, the applicability of the conventional two-phase flow functions used for porous media, such as Mualem-van Genuchten model, to prediction of the gas transport in the fractured rock mass are not well understood. The authors conducted the two types of in-situ tests, with different scales, a borehole gas-injection test and a chamber gas-injection test in fractured granitic rock. These tests were conducted in the Cretaceous granitic rocks at the Namikata underground LPG storage cavern construction site in Ehime Prefecture in Japan, preceding to the cavern scale gas-tightness test. A borehole injection test was conducted using vertical and sub-vertical boreholes drilled from the water injection tunnel nearly at the depth of the top of the cavern, EL-150m. A new type downhole gas injection equipment that is capable to create a small 'cavern' within a borehole was developed. After performing a series of preliminary tests to investigate the hydraulic conductivity and gas-tightness, i.e. threshold pressure, gas injection tests were conducted under different gas pressure. Fig.1 shows an example of the test results From a chamber test using a air pressurizing chamber with volume of approximately166m3, the gas-tightness was confirmed within the uncertainty of 22Pa under the storage pressure of 0.7MPa, however, significant air leakage occurred possibly through an open fracture intersecting the chamber just after cavern pressure exceeds the initial hydrostatic pressure at the ceiling level of the chamber. Anomalies

Validation of transport models using additive flux minimization technique

Energy Technology Data Exchange (ETDEWEB)

Pankin, A. Y.; Kruger, S. E. [Tech-X Corporation, 5621 Arapahoe Ave., Boulder, Colorado 80303 (United States); Groebner, R. J. [General Atomics, San Diego, California 92121 (United States); Hakim, A. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543-0451 (United States); Kritz, A. H.; Rafiq, T. [Department of Physics, Lehigh University, Bethlehem, Pennsylvania 18015 (United States)

2013-10-15

A new additive flux minimization technique is proposed for carrying out the verification and validation (V and V) of anomalous transport models. In this approach, the plasma profiles are computed in time dependent predictive simulations in which an additional effective diffusivity is varied. The goal is to obtain an optimal match between the computed and experimental profile. This new technique has several advantages over traditional V and V methods for transport models in tokamaks and takes advantage of uncertainty quantification methods developed by the applied math community. As a demonstration of its efficiency, the technique is applied to the hypothesis that the paleoclassical density transport dominates in the plasma edge region in DIII-D tokamak discharges. A simplified version of the paleoclassical model that utilizes the Spitzer resistivity for the parallel neoclassical resistivity and neglects the trapped particle effects is tested in this paper. It is shown that a contribution to density transport, in addition to the paleoclassical density transport, is needed in order to describe the experimental profiles. It is found that more additional diffusivity is needed at the top of the H-mode pedestal, and almost no additional diffusivity is needed at the pedestal bottom. The implementation of this V and V technique uses the FACETS::Core transport solver and the DAKOTA toolkit for design optimization and uncertainty quantification. The FACETS::Core solver is used for advancing the plasma density profiles. The DAKOTA toolkit is used for the optimization of plasma profiles and the computation of the additional diffusivity that is required for the predicted density profile to match the experimental profile.

Validation of transport models using additive flux minimization technique

International Nuclear Information System (INIS)

Pankin, A. Y.; Kruger, S. E.; Groebner, R. J.; Hakim, A.; Kritz, A. H.; Rafiq, T.

2013-01-01

A new additive flux minimization technique is proposed for carrying out the verification and validation (V and V) of anomalous transport models. In this approach, the plasma profiles are computed in time dependent predictive simulations in which an additional effective diffusivity is varied. The goal is to obtain an optimal match between the computed and experimental profile. This new technique has several advantages over traditional V and V methods for transport models in tokamaks and takes advantage of uncertainty quantification methods developed by the applied math community. As a demonstration of its efficiency, the technique is applied to the hypothesis that the paleoclassical density transport dominates in the plasma edge region in DIII-D tokamak discharges. A simplified version of the paleoclassical model that utilizes the Spitzer resistivity for the parallel neoclassical resistivity and neglects the trapped particle effects is tested in this paper. It is shown that a contribution to density transport, in addition to the paleoclassical density transport, is needed in order to describe the experimental profiles. It is found that more additional diffusivity is needed at the top of the H-mode pedestal, and almost no additional diffusivity is needed at the pedestal bottom. The implementation of this V and V technique uses the FACETS::Core transport solver and the DAKOTA toolkit for design optimization and uncertainty quantification. The FACETS::Core solver is used for advancing the plasma density profiles. The DAKOTA toolkit is used for the optimization of plasma profiles and the computation of the additional diffusivity that is required for the predicted density profile to match the experimental profile

Spatial-temporal data model and fractal analysis of transportation network in GIS environment

Science.gov (United States)

Feng, Yongjiu; Tong, Xiaohua; Li, Yangdong

2008-10-01

How to organize transportation data characterized by multi-time, multi-scale, multi-resolution and multi-source is one of the fundamental problems of GIS-T development. A spatial-temporal data model for GIS-T is proposed based on Spatial-temporal- Object Model. Transportation network data is systemically managed using dynamic segmentation technologies. And then a spatial-temporal database is built to integrally store geographical data of multi-time for transportation. Based on the spatial-temporal database, functions of spatial analysis of GIS-T are substantively extended. Fractal module is developed to improve the analyzing in intensity, density, structure and connectivity of transportation network based on the validation and evaluation of topologic relation. Integrated fractal with GIS-T strengthens the functions of spatial analysis and enriches the approaches of data mining and knowledge discovery of transportation network. Finally, the feasibility of the model and methods are tested thorough Guangdong Geographical Information Platform for Highway Project.

Activity transport models for PWR primary circuits; PWR-ydinvoimalaitoksen primaeaeripiirin aktiivisuuskulkeutumismallit

Energy Technology Data Exchange (ETDEWEB)

Tanner, V; Rosenberg, R [VTT Chemical Technology, Otaniemi (Finland)

1995-03-01

The corrosion products activated in the primary circuit form a major source of occupational radiation dose in the PWR reactors. Transport of corrosion activity is a complex process including chemistry, reactor physics, thermodynamics and hydrodynamics. All the mechanisms involved are not known and there is no comprehensive theory for the process, so experimental test loops and plant data are very important in research efforts. Several activity transport modelling attempts have been made to improve the water chemistry control and to minimise corrosion in PWR`s. In this research report some of these models are reviewed with special emphasis on models designed for Soviet VVER type reactors. (51 refs., 16 figs., 4 tabs.).

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

Higher-fidelity yet efficient modeling of radiation energy transport through three-dimensional clouds

International Nuclear Information System (INIS)

Hall, M.L.; Davis, A.B.

2005-01-01

Accurate modeling of radiative energy transport through cloudy atmospheres is necessary for both climate modeling with GCMs (Global Climate Models) and remote sensing. Previous modeling efforts have taken advantage of extreme aspect ratios (cells that are very wide horizontally) by assuming a 1-D treatment vertically - the Independent Column Approximation (ICA). Recent attempts to resolve radiation transport through the clouds have drastically changed the aspect ratios of the cells, moving them closer to unity, such that the ICA model is no longer valid. We aim to provide a higher-fidelity atmospheric radiation transport model which increases accuracy while maintaining efficiency. To that end, this paper describes the development of an efficient 3-D-capable radiation code that can be easily integrated into cloud resolving models as an alternative to the resident 1-D model. Applications to test cases from the Intercomparison of 3-D Radiation Codes (I3RC) protocol are shown

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

Coupled hydrogeological and reactive transport modelling of the Simpevarp area (Sweden)

International Nuclear Information System (INIS)

Molinero, Jorge; Raposo, Juan R.; Galindez, Juan M.; Arcos, David; Guimera, Jordi

2008-01-01

The Simpevarp area is one of the alternative sites being considered for the deep geological disposal of high level radioactive waste in Sweden. In this paper, a coupled regional groundwater flow and reactive solute transport model of the Simpevarp area is presented that integrates current hydrogeological and hydrochemical data of the area. The model simulates the current hydrochemical pattern of the groundwater system in the area. To that aim, a conceptual hydrochemical model was developed in order to represent the dominant chemical processes. Groundwater flow conditions were reproduced by taking into account fluid-density-dependent groundwater flow and regional hydrogeologic boundary conditions. Reactive solute transport calculations were performed on the basis of the velocity field so obtained. The model was calibrated and sensitivity analyses were carried out in order to investigate the effects of heterogeneities of hydraulic conductivity in the subsurface medium. Results provided by the reactive transport model are in good agreement with much of the measured hydrochemical data. This paper emphasizes the appropriateness of the use of reactive solute transport models when water-rock interaction reactions are involved, and demonstrates what powerful tools they are for the interpretation of hydrogeological and hydrochemical data from site geological repository characterization programs, by providing a qualitative framework for data analysis and testing of conceptual assumptions in a process-oriented approach

Intra-site Secure Transport Vehicle test and evaluation

International Nuclear Information System (INIS)

Scott, S.

1995-01-01

In the past many DOE and DoD facilities involved in handling nuclear material realized a need to enhance the safely and security for movement of sensitive materials within their facility, or ''intra-site''. There have been prior efforts to improve on-site transportation; however, there remains a requirement for enhanced on-site transportation at a number of facilities. The requirements for on-site transportation are driven by security, safety, and operational concerns. The Intra-site Secure Transport Vehicle (ISTV) was designed to address these concerns specifically for DOE site applications with a standardized vehicle design. This paper briefly reviews the ISTV design features providing significant enhancement of onsite transportation safety and security, and also describes the test and evaluation activities either complete of underway to validate the vehicle design and operation

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.

Rail-Cask Tests: Normal-Conditionsof- Transport Tests of Surrogate PWR Fuel Assemblies in an ENSA ENUN 32P Cask.

Energy Technology Data Exchange (ETDEWEB)

McConnell, Paul E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ross, Steven [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Grey, Carissa Ann [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Uncapher, William Leonard [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Arviso, Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Garmendia, Rafael [Equipos Nucleares Sociedad Anonima, Madrid (Spain); Fernandez Perez, Ismael [Equipos Nucleares Sociedad Anonima, Madrid (Spain); Palacio, Alejandro [Equipos Nucleares Sociedad Anonima, Madrid (Spain); Calleja, Guillermo [Equipos Nucleares Sociedad Anonima, Madrid (Spain); Garrido, David [COORDINADORA, Madrid (Spain); Rodriguez Casas, Ana [COORDINADORA, Madrid (Spain); Gonzalez Garcia, Luis [COORDINADORA, Madrid (Spain); Chilton, Lyman Wes [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ammerman, Douglas J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Walz, Jacob [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gershon, Sabina [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Saltzstein, Sylvia J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sorenson, Ken [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Klymyshyn, Nicholas [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hanson, Brady [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Pena, Ruben [Transportation Technology Center, Inc., Pueblo, CO (United States); Walker, Russell [Transportation Technology Center, Inc., Pueblo, CO (United States)

2018-01-01

This report describes tests conducted using a full-size rail cask, the ENSA ENUN 32P, involving handling of the cask and transport of the cask via truck, ships, and rail. The purpose of the tests was to measure strains and accelerations on surrogate pressurized water reactor fuel rods when the fuel assemblies were subjected to Normal Conditions of Transport within the rail cask. In addition, accelerations were measured on the transport platform, the cask cradle, the cask, and the basket within the cask holding the assemblies. These tests were an international collaboration that included Equipos Nucleares S.A., Sandia National Laboratories, Pacific Northwest National Laboratory, Coordinadora Internacional de Cargas S.A., the Transportation Technology Center, Inc., the Korea Radioactive Waste Agency, and the Korea Atomic Energy Research Institute. All test results in this report are PRELIMINARY – complete analyses of test data will be completed and reported in FY18. However, preliminarily: The strains were exceedingly low on the surrogate fuel rods during the rail-cask tests for all the transport and handling modes. The test results provide a compelling technical basis for the safe transport of spent fuel.

Flight Test Maneuvers for Efficient Aerodynamic Modeling

Science.gov (United States)

Morelli, Eugene A.

2011-01-01

Novel flight test maneuvers for efficient aerodynamic modeling were developed and demonstrated in flight. Orthogonal optimized multi-sine inputs were applied to aircraft control surfaces to excite aircraft dynamic response in all six degrees of freedom simultaneously while keeping the aircraft close to chosen reference flight conditions. Each maneuver was designed for a specific modeling task that cannot be adequately or efficiently accomplished using conventional flight test maneuvers. All of the new maneuvers were first described and explained, then demonstrated on a subscale jet transport aircraft in flight. Real-time and post-flight modeling results obtained using equation-error parameter estimation in the frequency domain were used to show the effectiveness and efficiency of the new maneuvers, as well as the quality of the aerodynamic models that can be identified from the resultant flight data.

The Grimsel radionuclide migration experiment - a contribution to raising confidence in the validity of solute transport models used in performance assessment

International Nuclear Information System (INIS)

Frick, U.

1995-01-01

The safety assessment of radioactive waste repositories is to provide confidence that the predictive models utilized are applicable for the specific repository systems. Nagra has carried out radionuclide migration experiments at the Grimsel underground test site (Switzerland) for testing of currently used methodologies, data bases, conceptual approaches and codes for modeling radionuclide transport through fractured host rocks. Specific objectives included: identification of the relevant transport processes, to test the extrapolation of laboratory sorption data to field conditions, and to demonstrate the applicability of currently used methodology for conceptualizing or building realistic transport models. Field tests and transport modeling work are complemented by an extensive laboratory program. The field experimental activities focused predominantly on establishing appropriate conditions for identifying relevant transport mechanisms on the scale of a few meters, aiming at full recovery of injected tracers, simple geometry and long-term stability of induced dipole flow fields. A relatively simple homogeneous, dual-porosity advection/diffusion model was built with input from a state of the art petrographic characterisation of the water conducting feature. It was possible to calibrate the model from conservative tracer breakthrough curves. (J.S.). 21 refs., 14 figs., 4 tabs

A hybrid model to predict the entrainment and subsurface transport of oil

International Nuclear Information System (INIS)

Spaulding, M.L.; Odulo, A.; Kolluru, V.S.

1992-01-01

The entrainment of surface oil into the water column and its subsequent subsurface transport and dispersion are predicted by a hybrid analytic-numerical solution to the advective diffusion equation. Total oil or selected hydrocarbon component concentrations in the water column are predicted. Assuming that the principal mechanism for entrainment is due to breaking waves, the oil entrainment rate is specified using the empirically based algorithm of Delvigne and Sweeney (1988). The subsurface transport model explicitly accounts for buoyant forces on dispersed oil by droplet size. Application of the model to an analytic test case and several hypothetical scenarios illustrates the model's utility. 35 refs., 8 figs., 2 tabs

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....

Time-Varying Hydraulic Gradient Model of Paste-Like Tailings in Long-Distance Pipeline Transportation

Directory of Open Access Journals (Sweden)

Li Yang

2017-01-01

Full Text Available Paste-like tailings slurry (PTLS is always simplified as a Bingham plastic fluid, leading to excessive computational errors in the calculation of the hydraulic gradient. In the case of paste-like tailings in long-distance pipeline transportation, to explore a high-precision and reliable hydraulic gradient formula, the rheological behavior of paste-like tailings slurry was analyzed, a time-varying hydraulic gradient model was constructed, and a series of laboratory shear tests were conducted. The results indicate that the PTLS shows noticeable shear-thinning characteristics in constant shear tests; the calculated hydraulic gradient declined by about 56%, from 4.44 MPa·km−1 to 1.95 MPa·km−1 within 253 s, and remained constant for the next four hours during the pipeline transportation. Comparing with the balance hydraulic gradient obtained in a semi-industrial loop test, the computational errors of those calculated by using the time-varying hydraulic gradient model, Jinchuan formula, and Shanxi formula are 15%, 78%, and 130%, respectively. Therefore, our model is a feasible and high-precision solution for the calculation of the hydraulic gradient of paste-like tailings in long-distance pipeline transportation.

Stable isotope reactive transport modeling in water-rock interactions during CO2 injection

Science.gov (United States)

Hidalgo, Juan J.; Lagneau, Vincent; Agrinier, Pierre

2010-05-01

Stable isotopes can be of great usefulness in the characterization and monitoring of CO2 sequestration sites. Stable isotopes can be used to track the migration of the CO2 plume and identify leakage sources. Moreover, they provide unique information about the chemical reactions that take place on the CO2-water-rock system. However, there is a lack of appropriate tools that help modelers to incorporate stable isotope information into the flow and transport models used in CO2 sequestration problems. In this work, we present a numerical tool for modeling the transport of stable isotopes in groundwater reactive systems. The code is an extension of the groundwater single-phase flow and reactive transport code HYTEC [2]. HYTEC's transport module was modified to include element isotopes as separate species. This way, it is able to track isotope composition of the system by computing the mixing between the background water and the injected solution accounting for the dependency of diffusion on the isotope mass. The chemical module and database have been expanded to included isotopic exchange with minerals and the isotope fractionation associated with chemical reactions and mineral dissolution or precipitation. The performance of the code is illustrated through a series of column synthetic models. The code is also used to model the aqueous phase CO2 injection test carried out at the Lamont-Doherty Earth Observatory site (Palisades, New York, USA) [1]. References [1] N. Assayag, J. Matter, M. Ader, D. Goldberg, and P. Agrinier. Water-rock interactions during a CO2 injection field-test: Implications on host rock dissolution and alteration effects. Chemical Geology, 265(1-2):227-235, July 2009. [2] Jan van der Lee, Laurent De Windt, Vincent Lagneau, and Patrick Goblet. Module-oriented modeling of reactive transport with HYTEC. Computers & Geosciences, 29(3):265-275, April 2003.

Modeling unsteady-state VOC transport in simulated waste drums

International Nuclear Information System (INIS)

Liekhus, K.J.; Gresham, G.L.; Peterson, E.S.; Rae, C.; Hotz, N.J.; Connolly, M.J.

1994-01-01

This report is a revision of an EG ampersand G Idaho informal report originally titled Modeling VOC Transport in Simulated Waste Drums. A volatile organic compound (VOC) transport model has been developed to describe unsteady-state VOC permeation and diffusion within a waste drum. Model equations account for three primary mechanisms for VOC transport from a void volume within the drum. These mechanisms are VOC permeation across a polymer boundary, VOC diffusion across an opening in a volume boundary, and VOC solubilization in a polymer boundary. A series of lab-scale experiments was performed in which the VOC concentration was measured in simulated waste drums under different conditions. A lab-scale simulated waste drum consisted of a sized-down 55-gal metal drum containing a modified rigid polyethylene drum liner. Four polyethylene bags were sealed inside a large polyethylene bag, supported by a wire cage, and placed inside the drum liner. The small bags were filled with VOC-air gas mixture and the VOC concentration was measured throughout the drum over a period of time. Test variables included the type of VOC-air gas mixtures introduced into the small bags, the small bag closure type, and the presence or absence of a variable external heat source. Model results were calculated for those trials where the permeability had been measured

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.

Collaborative testing of turbulence models

Science.gov (United States)

Bradshaw, P.

1992-12-01

This project, funded by AFOSR, ARO, NASA, and ONR, was run by the writer with Profs. Brian E. Launder, University of Manchester, England, and John L. Lumley, Cornell University. Statistical data on turbulent flows, from lab. experiments and simulations, were circulated to modelers throughout the world. This is the first large-scale project of its kind to use simulation data. The modelers returned their predictions to Stanford, for distribution to all modelers and to additional participants ('experimenters')--over 100 in all. The object was to obtain a consensus on the capabilities of present-day turbulence models and identify which types most deserve future support. This was not completely achieved, mainly because not enough modelers could produce results for enough test cases within the duration of the project. However, a clear picture of the capabilities of various modeling groups has appeared, and the interaction has been helpful to the modelers. The results support the view that Reynolds-stress transport models are the most accurate.

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....

Computerized transportation model for the NRC Physical Protection Project. Versions I and II

International Nuclear Information System (INIS)

Anderson, G.M.

1978-01-01

Details on two versions of a computerized model for the transportation system of the NRC Physical Protection Project are presented. The Version I model permits scheduling of all types of transport units associated with a truck fleet, including truck trailers, truck tractors, escort vehicles and crews. A fixed-fleet itinerary construction process is used in which iterations on fleet size are required until the service requirements are satisfied. The Version II model adds an aircraft mode capability and provides for a more efficient non-fixed-fleet itinerary generation process. Test results using both versions are included

Development of Numerical Grids for UZ Flow and Transport Modeling

International Nuclear Information System (INIS)

Hinds, J.

2001-01-01

This Analysis/Model Report (AMR) describes the methods used to develop numerical grids of the unsaturated hydrogeologic system beneath Yucca Mountain. Numerical grid generation is an integral part of the development of a complex, three-dimensional (3-D) model, such as the Unsaturated-Zone Flow and Transport Model (UZ Model) of Yucca Mountain. The resulting numerical grids, developed using current geologic, hydrogeologic, and mineralogic data, provide the necessary framework to: (1) develop calibrated hydrogeologic property sets and flow fields, (2) test conceptual hypotheses of flow and transport, and (3) predict flow and transport behavior under a variety of climatic and thermal loading conditions. Revision 00 of the work described herein follows the planning and work direction outlined in the ''Development of Numerical Grids for UZ Flow and Transport Modeling'' (CRWMS M and O 1999c). The technical scope, content, and management of ICN 01 of this AMR is currently controlled by the planning document, ''Technical Work Plan for Unsaturated Zone (UZ) Flow and Transport Process Model Report'' (BSC 2001a). The scope for the TBV resolution actions in this ICN is described in the ''Technical Work Plan for: Integrated Management of Technical Product Input Department'' (BSC 2001 b, Addendum B, Section 4.1). The steps involved in numerical grid development include: (1) defining the location of important calibration features, (2) determining model grid layers and fault geometry based on the Geologic Framework Model (GFM), the Integrated Site Model (ISM), and definition of hydrogeologic units (HGUs), (3) analyzing and extracting GFM and ISM data pertaining to layer contacts and property distributions, (4) discretizing and refining the two-dimensional (2-D), plan-view numerical grid, (5) generating the 3-D grid with finer resolution at the repository horizon and within the Calico Hills nonwelded (CHn) hydrogeologic unit, and (6) formulating the dual-permeability mesh. The

Inverse modeling of multicomponent reactive transport through single and dual porosity media

Science.gov (United States)

Samper, Javier; Zheng, Liange; Fernández, Ana María; Montenegro, Luis

2008-06-01

Compacted bentonite is foreseen as buffer material for high-level radioactive waste in deep geological repositories because it provides hydraulic isolation, chemical stability, and radionuclide sorption. A wide range of laboratory tests were performed within the framework of FEBEX ( Full-scale Engineered Barrier EXperiment) project to characterize buffer properties and develop numerical models for FEBEX bentonite. Here we present inverse single and dual-continuum multicomponent reactive transport models of a long-term permeation test performed on a 2.5 cm long sample of FEBEX bentonite. Initial saline bentonite porewater was flushed with 5.5 pore volumes of fresh granitic water. Water flux and chemical composition of effluent waters were monitored during almost 4 years. The model accounts for solute advection and diffusion and geochemical reactions such as aqueous complexation, acid-base, cation exchange, protonation/deprotonation by surface complexation and dissolution/precipitation of calcite, chalcedony and gypsum. All of these processes are assumed at local equilibrium. Similar to previous studies of bentonite porewater chemistry on batch systems which attest the relevance of protonation/deprotonation on buffering pH, our results confirm that protonation/deprotonation is a key process in maintaining a stable pH under dynamic transport conditions. Breakthrough curves of reactive species are more sensitive to initial porewater concentration than to effective diffusion coefficient. Optimum estimates of initial porewater chemistry of saturated compacted FEBEX bentonite are obtained by solving the inverse problem of multicomponent reactive transport. While the single-continuum model reproduces the trends of measured data for most chemical species, it fails to match properly the long tails of most breakthrough curves. Such limitation is overcome by resorting to a dual-continuum reactive transport model.

Modified finite element transport model, FETRA, for sediment and radionuclide migration in open coastal waters

International Nuclear Information System (INIS)

Onishi, Y.; Arnold, E.M.; Mayer, D.W.

1979-08-01

The finite element model, FETRA, simulates transport of sediment and radionuclides (and other contaminants, such as heavy metals, pesticides, and other toxic substances) in surface water bodies. The model is an unsteady, two-dimensional (longitudinal and lateral) model which consists of the following three submodels coupled to include sediment-contaminant interactions: (1) sediment transport submodel, (2) dissolved contaminant transport submodel, and (3) particulate contaminant (contaminant adsorbed by sediment) transport submodel. Under the current phase of the study, FETRA was modified to include sediment-wave interaction in order to extend the applicability of the model to coastal zones and large lakes (e.g., the Great Lakes) where wave actions can be one of the dominant mechanisms to transport sediment and toxic contaminant. FETRA was further modified to handle both linear and quadratic approximations to velocity and depth distributions in order to be compatible with various finite element hydrodynamic models (e.g., RMA II and CAFE) which supply hydrodynamic input data to FETRA. The next step is to apply FETRA to coastal zones to simulate transport of sediment and radionuclides with their interactions in order to test and verify the model under marine and large lacustrine environments

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

An evaluation of twelve nested models of transperitoneal transport of urea

DEFF Research Database (Denmark)

Graff, J; Fugleberg, S; Joffe, P

1995-01-01

the mechanism(s) of transperitoneal urea transport and to test the one-compartment assumption for urea. A total of 12 nested models were formulated and validated on the basis of experimental results obtained from 23 non-diabetic patients undergoing peritoneal dialysis. The validation procedure demonstrated...

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.

Development of numerical Grids for UZ Flow and Transport Modeling

International Nuclear Information System (INIS)

P. Dobson

2004-01-01

This report describes the methods used to develop numerical grids of the unsaturated hydrogeologic system beneath Yucca Mountain, Nevada. Numerical grid generation is an integral part of the development of the unsaturated zone (UZ) flow and transport model, a complex, three-dimensional (3-D) model of Yucca Mountain. This revision contains changes made to improve the clarity of the description of grid generation. The numerical grids, developed using current geologic, hydrogeologic, and mineralogic data, provide the necessary framework to: (1) develop calibrated hydrogeologic property sets and flow fields, (2) test conceptual hypotheses of flow and transport, and (3) predict flow and transport behavior under a variety of climatic and thermal-loading conditions. The technical scope, content, and management for the current revision of this report are described in the planning document ''Technical Work Plan for: Unsaturated Zone Flow Analysis and Model Report Integration'' (BSC 2004 [DIRS 169654], Section 2). Grids generated and documented in this report supersede those documented in Revision 00 of this report, ''Development of Numerical Grids for UZ Flow and Transport Modeling'' (BSC 2001 [DIRS 159356]). The grids presented in this report are the same as those developed in Revision 01 (BSC 2003 [DIRS 160109]); however, the documentation of the development of the grids in Revision 02 has been updated to address technical inconsistencies and achieve greater transparency, readability, and traceability. The constraints, assumptions, and limitations associated with this report are discussed in the appropriate sections that follow

Thermal test and analysis for transporting vitrified high-level radioactive wastes

International Nuclear Information System (INIS)

Yamakawa, H.; Gomi, Y.; Ozaki, S.; Kato, O.; Tamaki, H.

1993-01-01

As a part of the safety demonstration tests for transport casks of high level radioactive vitrified wastes, the thermal tests of the cask (left unattended at an ambient temperature of 38degC for a period of one week) were executed before and after the side free drop test (from height of 30 cm). This condition was set according to the prospect of the damage of contents (baskets, etc.) by the impact force at the drop test. It was shown that the cask temperatures at the representative parts, such as the vitrified wastes, the containment system, and the protection wire net, were lower than allowable values. From the result of measured temperatures it was considered that no damages and no large deformations could happen to the contents in this drop test. Thermal analysis was also done to establish the analysis model. (J.P.N.)

STRATAQ: A three-dimensional Chemical Transport Model of the stratosphere

Directory of Open Access Journals (Sweden)

B. Grassi

2002-06-01

Full Text Available A three-dimensional (3-D Chemical Transport Model (CTM of the stratosphere has been developed and used for a test study of the evolution of chemical species in the arctic lower stratosphere during winter 1996/97. This particular winter has been chosen for testing the model’s capabilities for its remarkable dynamical situation (very cold and strong polar vortex along with the availability of sparse chlorine, HNO3 and O3 data, showing also very low O3 values in late March/April. Due to those unusual features, the winter 1996/97 can be considered an excellent example of the impact of both dynamics and heterogeneous reactions on the chemistry of the stratosphere. Model integration has been performed from January to March 1997 and the resulting long-lived and short-lived tracer fields compared with available measurements. The model includes a detailed gas phase chemical scheme and a parameterization of the heterogeneous reactions occurring on liquid aerosol and polar stratospheric cloud (PSC surfaces. The transport is calculated using a semi-lagrangian flux scheme, forced by meteorological analyses. In such form, the STRATAQ CTM model is suitable for short-term integrations to study transport and chemical evolution related to "real" meteorological situations. Model simulation during the chosen winter shows intense PSC formation, with noticeable local HNO3 capture by PSCs, and the activation of vortex air leading to chlorine production and subsequent O3 destruction. The resulting model fields show generally good agreement with satellite data (MLS and TOMS, although the available observations, due to their limited number and time/space sparse nature, are not enough to effectively constraint the model. In particular, the model seems to perform well in reproducing the rapid processing of air inside the polar vortex on PSC converting reservoir species in active chlorine. In addition, it satisfactorily reproduces the morphology of the continuous O3

STRATAQ: A three-dimensional Chemical Transport Model of the stratosphere

Directory of Open Access Journals (Sweden)

B. Grassi

Full Text Available A three-dimensional (3-D Chemical Transport Model (CTM of the stratosphere has been developed and used for a test study of the evolution of chemical species in the arctic lower stratosphere during winter 1996/97. This particular winter has been chosen for testing the model’s capabilities for its remarkable dynamical situation (very cold and strong polar vortex along with the availability of sparse chlorine, HNO₃ and O₃ data, showing also very low O₃ values in late March/April. Due to those unusual features, the winter 1996/97 can be considered an excellent example of the impact of both dynamics and heterogeneous reactions on the chemistry of the stratosphere. Model integration has been performed from January to March 1997 and the resulting long-lived and short-lived tracer fields compared with available measurements. The model includes a detailed gas phase chemical scheme and a parameterization of the heterogeneous reactions occurring on liquid aerosol and polar stratospheric cloud (PSC surfaces. The transport is calculated using a semi-lagrangian flux scheme, forced by meteorological analyses. In such form, the STRATAQ CTM model is suitable for short-term integrations to study transport and chemical evolution related to "real" meteorological situations. Model simulation during the chosen winter shows intense PSC formation, with noticeable local HNO₃ capture by PSCs, and the activation of vortex air leading to chlorine production and subsequent O₃ destruction. The resulting model fields show generally good agreement with satellite data (MLS and TOMS, although the available observations, due to their limited number and time/space sparse nature, are not enough to effectively constraint the model. In particular, the model seems to perform well in reproducing the rapid processing of air inside the polar vortex on PSC converting reservoir species in active chlorine. In addition, it

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...

Transport rankings of non-steroidal antiinflammatory drugs across blood-brain barrier in vitro models.

Directory of Open Access Journals (Sweden)

Iveta Novakova

Full Text Available The aim of this work was to conduct a comprehensive study about the transport properties of NSAIDs across the blood-brain barrier (BBB in vitro. Transport studies with celecoxib, diclofenac, ibuprofen, meloxicam, piroxicam and tenoxicam were accomplished across Transwell models based on cell line PBMEC/C1-2, ECV304 or primary rat brain endothelial cells. Single as well as group substance studies were carried out. In group studies substance group compositions, transport medium and serum content were varied, transport inhibitors verapamil and probenecid were added. Resulted permeability coefficients were compared and normalized to internal standards diazepam and carboxyfluorescein. Transport rankings of NSAIDs across each model were obtained. Single substance studies showed similar rankings as corresponding group studies across PBMEC/C1-2 or ECV304 cell layers. Serum content, glioma conditioned medium and inhibitors probenecid and verapamil influenced resulted permeability significantly. Basic differences of transport properties of the investigated NSAIDs were similar comparing all three in vitro BBB models. Different substance combinations in the group studies and addition of probenecid and verapamil suggested that transporter proteins are involved in the transport of every tested NSAID. Results especially underlined the importance of same experimental conditions (transport medium, serum content, species origin, cell line for proper data comparison.

Automatic modeling for the Monte Carlo transport code Geant4 in MCAM

International Nuclear Information System (INIS)

Nie Fanzhi; Hu Liqin; Wang Guozhong; Wang Dianxi; Wu Yican; Wang Dong; Long Pengcheng; FDS Team

2014-01-01

Geant4 is a widely used Monte Carlo transport simulation package. Its geometry models could be described in geometry description markup language (GDML), but it is time-consuming and error-prone to describe the geometry models manually. This study implemented the conversion between computer-aided design (CAD) geometry models and GDML models. The conversion program was integrated into Multi-Physics Coupling Analysis Modeling Program (MCAM). The tests, including FDS-Ⅱ model, demonstrated its accuracy and feasibility. (authors)

Thermodynamic Modeling of Gas Transport in Glassy Polymeric Membranes.

Science.gov (United States)

Minelli, Matteo; Sarti, Giulio Cesare

2017-08-19

Solubility and permeability of gases in glassy polymers have been considered with the aim of illustrating the applicability of thermodynamically-based models for their description and prediction. The solubility isotherms are described by using the nonequilibrium lattice fluid (NELF) (model, already known to be appropriate for nonequilibrium glassy polymers, while the permeability isotherms are described through a general transport model in which diffusivity is the product of a purely kinetic factor, the mobility coefficient, and a thermodynamic factor. The latter is calculated from the NELF model and mobility is considered concentration-dependent through an exponential relationship containing two parameters only. The models are tested explicitly considering solubility and permeability data of various penetrants in three glassy polymers, PSf, PPh and 6FDA-6FpDA, selected as the reference for different behaviors. It is shown that the models are able to calculate the different behaviors observed, and in particular the permeability dependence on upstream pressure, both when it is decreasing as well as when it is increasing, with no need to invoke the onset of additional plasticization phenomena. The correlations found between polymer and penetrant properties with the two parameters of the mobility coefficient also lead to the predictive ability of the transport 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.)

PTC test bed upgrades to provide ACSES testing support capabilities at transportation technology center.

Science.gov (United States)

2015-06-01

FRA Task Order 314 upgraded the Positive Train Control (PTC) Test Bed at the Transportation Technology Center to support : testing of PTC systems, components, and related equipment associated with the Advanced Civil Speed Enforcement System : (ACSES)...

Radon transport modelling: User's guide to RnMod3d

International Nuclear Information System (INIS)

Andersen, C.E.

2000-08-01

RnMod3d is a numerical computer model of soil-gas and radon transport in porous media. It can be used, for example, to study radon entry from soil into houses in response to indoor-outdoor pressure differences or changes in atmospheric pressure. It can also be used for flux calculations of radon from the soil surface or to model radon exhalation from building materials such as concrete. The finite-volume model is a technical research tool, and it cannot be used meaningfully without good understanding of the involved physical equations. Some understanding of numerical mathematics and the programming language Pascal is also required. Originally, the code was developed for internal use at Risoe only. With this guide, however, it should be possible for others to use the model. Three-dimensional steady-state or transient problems with Darcy flow of soil gas and combined generation, radioactive decay, diffusion and advection of radon can be solved. Moisture is included in the model, and partitioning of radon between air, water and soil grains (adsorption) is taken into account. Most parameters can change in time and space, and transport parameters (diffusivity and permeability) may be anisotropic. This guide includes benchmark tests based on simple problems with known solutions. RnMod3d has also been part of an international model intercomparison exercise based on more complicated problems without known solutions. All tests show that RnMod3d gives results of good quality. (au)

Transport of fluid and solutes in the body I. Formulation of a mathematical model.

Science.gov (United States)

Gyenge, C C; Bowen, B D; Reed, R K; Bert, J L

1999-09-01

A compartmental model of short-term whole body fluid, protein, and ion distribution and transport is formulated. The model comprises four compartments: a vascular and an interstitial compartment, each with an embedded cellular compartment. The present paper discusses the assumptions on which the model is based and describes the equations that make up the model. Fluid and protein transport parameters from a previously validated model as well as ionic exchange parameters from the literature or from statistical estimation [see companion paper: C. C. Gyenge, B. D. Bowen, R. K. Reed, and J. L. Bert. Am. J. Physiol. 277 (Heart Circ. Physiol. 46): H1228-H1240, 1999] are used in formulating the model. The dynamic model has the ability to simulate 1) transport across the capillary membrane of fluid, proteins, and small ions and their distribution between the vascular and interstitial compartments; 2) the changes in extracellular osmolarity; 3) the distribution and transport of water and ions associated with each of the cellular compartments; 4) the cellular transmembrane potential; and 5) the changes of volume in the four fluid compartments. The validation and testing of the proposed model against available experimental data are presented in the companion paper.

Optimization of atmospheric transport models on HPC platforms

Science.gov (United States)

de la Cruz, Raúl; Folch, Arnau; Farré, Pau; Cabezas, Javier; Navarro, Nacho; Cela, José María

2016-12-01

The performance and scalability of atmospheric transport models on high performance computing environments is often far from optimal for multiple reasons including, for example, sequential input and output, synchronous communications, work unbalance, memory access latency or lack of task overlapping. We investigate how different software optimizations and porting to non general-purpose hardware architectures improve code scalability and execution times considering, as an example, the FALL3D volcanic ash transport model. To this purpose, we implement the FALL3D model equations in the WARIS framework, a software designed from scratch to solve in a parallel and efficient way different geoscience problems on a wide variety of architectures. In addition, we consider further improvements in WARIS such as hybrid MPI-OMP parallelization, spatial blocking, auto-tuning and thread affinity. Considering all these aspects together, the FALL3D execution times for a realistic test case running on general-purpose cluster architectures (Intel Sandy Bridge) decrease by a factor between 7 and 40 depending on the grid resolution. Finally, we port the application to Intel Xeon Phi (MIC) and NVIDIA GPUs (CUDA) accelerator-based architectures and compare performance, cost and power consumption on all the architectures. Implications on time-constrained operational model configurations are discussed.

SedFoam-2.0: a 3-D two-phase flow numerical model for sediment transport

Directory of Open Access Journals (Sweden)

J. Chauchat

2017-11-01

Full Text Available In this paper, a three-dimensional two-phase flow solver, SedFoam-2.0, is presented for sediment transport applications. The solver is extended from twoPhaseEulerFoam available in the 2.1.0 release of the open-source CFD (computational fluid dynamics toolbox OpenFOAM. In this approach the sediment phase is modeled as a continuum, and constitutive laws have to be prescribed for the sediment stresses. In the proposed solver, two different intergranular stress models are implemented: the kinetic theory of granular flows and the dense granular flow rheology μ(I. For the fluid stress, laminar or turbulent flow regimes can be simulated and three different turbulence models are available for sediment transport: a simple mixing length model (one-dimensional configuration only, a k − ε, and a k − ω model. The numerical implementation is demonstrated on four test cases: sedimentation of suspended particles, laminar bed load, sheet flow, and scour at an apron. These test cases illustrate the capabilities of SedFoam-2.0 to deal with complex turbulent sediment transport problems with different combinations of intergranular stress and turbulence models.

SedFoam-2.0: a 3-D two-phase flow numerical model for sediment transport

Science.gov (United States)

Chauchat, Julien; Cheng, Zhen; Nagel, Tim; Bonamy, Cyrille; Hsu, Tian-Jian

2017-11-01

In this paper, a three-dimensional two-phase flow solver, SedFoam-2.0, is presented for sediment transport applications. The solver is extended from twoPhaseEulerFoam available in the 2.1.0 release of the open-source CFD (computational fluid dynamics) toolbox OpenFOAM. In this approach the sediment phase is modeled as a continuum, and constitutive laws have to be prescribed for the sediment stresses. In the proposed solver, two different intergranular stress models are implemented: the kinetic theory of granular flows and the dense granular flow rheology μ(I). For the fluid stress, laminar or turbulent flow regimes can be simulated and three different turbulence models are available for sediment transport: a simple mixing length model (one-dimensional configuration only), a k - ɛ, and a k - ω model. The numerical implementation is demonstrated on four test cases: sedimentation of suspended particles, laminar bed load, sheet flow, and scour at an apron. These test cases illustrate the capabilities of SedFoam-2.0 to deal with complex turbulent sediment transport problems with different combinations of intergranular stress and turbulence models.

Phase I Hydrologic Data for the Groundwater Flow and Contaminant Transport Model of Corrective Action Unit 97: Yucca Flat/Climax Mine, Nevada Test Site, Nye County, Nevada, Rev. No.: 0

Energy Technology Data Exchange (ETDEWEB)

John McCord

2006-06-01

The U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Site Office (NNSA/NSO) initiated the Underground Test Area (UGTA) Project to assess and evaluate the effects of the underground nuclear weapons tests on groundwater beneath the Nevada Test Site (NTS) and vicinity. The framework for this evaluation is provided in Appendix VI, Revision No. 1 (December 7, 2000) of the Federal Facility Agreement and Consent Order (FFACO, 1996). Section 3.0 of Appendix VI ''Corrective Action Strategy'' of the FFACO describes the process that will be used to complete corrective actions specifically for the UGTA Project. The objective of the UGTA corrective action strategy is to define contaminant boundaries for each UGTA corrective action unit (CAU) where groundwater may have become contaminated from the underground nuclear weapons tests. The contaminant boundaries are determined based on modeling of groundwater flow and contaminant transport. A summary of the FFACO corrective action process and the UGTA corrective action strategy is provided in Section 1.5. The FFACO (1996) corrective action process for the Yucca Flat/Climax Mine CAU 97 was initiated with the Corrective Action Investigation Plan (CAIP) (DOE/NV, 2000a). The CAIP included a review of existing data on the CAU and proposed a set of data collection activities to collect additional characterization data. These recommendations were based on a value of information analysis (VOIA) (IT, 1999), which evaluated the value of different possible data collection activities, with respect to reduction in uncertainty of the contaminant boundary, through simplified transport modeling. The Yucca Flat/Climax Mine CAIP identifies a three-step model development process to evaluate the impact of underground nuclear testing on groundwater to determine a contaminant boundary (DOE/NV, 2000a). The three steps are as follows: (1) Data compilation and analysis that provides the necessary modeling

Modelling contaminant transport using site specific data from Vaalputs

International Nuclear Information System (INIS)

Botha, J.F.

1986-01-01

The transport of a contaminant through the upper layers of the earth's surface is a complex phenomenon. To develop a model for this, requires a good understanding of the physical nature of the phenomenon. This paper discusses two difficulties frequently encountered in developing such a model - the nature of the subsurface and the mathematical representation of the unsaturated hydraulic parameters. It is proposed that information obtained from pump- and packer tests be used to circumvent the first difficulty, and that the unsaturated flow parameters be approximated by C -∞ continuous function

Significance of flow clustering and sequencing on sediment transport: 1D sediment transport modelling

Science.gov (United States)

Hassan, Kazi; Allen, Deonie; Haynes, Heather

2016-04-01

This paper considers 1D hydraulic model data on the effect of high flow clusters and sequencing on sediment transport. Using observed flow gauge data from the River Caldew, England, a novel stochastic modelling approach was developed in order to create alternative 50 year flow sequences. Whilst the observed probability density of gauge data was preserved in all sequences, the order in which those flows occurred was varied using the output from a Hidden Markov Model (HMM) with generalised Pareto distribution (GP). In total, one hundred 50 year synthetic flow series were generated and used as the inflow boundary conditions for individual flow series model runs using the 1D sediment transport model HEC-RAS. The model routed graded sediment through the case study river reach to define the long-term morphological changes. Comparison of individual simulations provided a detailed understanding of the sensitivity of channel capacity to flow sequence. Specifically, each 50 year synthetic flow sequence was analysed using a 3-month, 6-month or 12-month rolling window approach and classified for clusters in peak discharge. As a cluster is described as a temporal grouping of flow events above a specified threshold, the threshold condition used herein is considered as a morphologically active channel forming discharge event. Thus, clusters were identified for peak discharges in excess of 10%, 20%, 50%, 100% and 150% of the 1 year Return Period (RP) event. The window of above-peak flows also required cluster definition and was tested for timeframes 1, 2, 10 and 30 days. Subsequently, clusters could be described in terms of the number of events, maximum peak flow discharge, cumulative flow discharge and skewness (i.e. a description of the flow sequence). The model output for each cluster was analysed for the cumulative flow volume and cumulative sediment transport (mass). This was then compared to the total sediment transport of a single flow event of equivalent flow volume

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

Transport Assessment - Arid Task: model verification studies - FY 1983. Annual report

International Nuclear Information System (INIS)

Jones, T.L.; Kirkham, R.R.; Gibson, D.

1983-08-01

The current focus of the Transport Assessment- Arid Task is the evaluation of evaporation and transpiration submodels used in water flow models. Models will be evaluated by how accurately they simulate field water balance data. To date we have: (1) selected four evaporation models to be tested, (2) constructed an evaporation test case, and (3) started collection of data for a transpiration test case. Evaluation of the evaporation models will be completed during FY83, with results published in September. The evaporation test case contains data describing soil water content, water storage, as well as drainage rates observed in the unvegetated lysimeters of the BWTF. For example, data show deep drainage accounted for 8% of the natural precipitation, but rose to 25% after irrigation doubled total precipitation. This year, deep drainage was also observed in vegetated soils. These results refute a commonly held assumption that evapotranspiration eliminates deep drainage in arid soils

Decision-Making in Pediatric Transport Team Dispatch Using Script Concordance Testing.

Science.gov (United States)

Rajapreyar, Prakadeshwari; Marcdante, Karen; Zhang, Liyun; Simpson, Pippa; Meyer, Michael T

2017-11-01

Our objective was to compare decision-making in dispatching pediatric transport teams by Medical Directors of pediatric transport teams (serving as experts) to that of Pediatric Intensivists and Critical Care fellows who often serve as Medical Control physicians. Understanding decision-making around team composition and dispatch could impact clinical management, cost effectiveness, and educational needs. Survey was developed using Script Concordance Testing guidelines. The survey contained 15 transport case vignettes covering 20 scenarios (45 questions). Eleven scenarios assessed impact of intrinsic patient factors (e.g., procedural needs), whereas nine assessed extrinsic factors (e.g., weather). Pediatric Critical Care programs accredited by the Accreditation Council for Graduate Medical Education (the United States). Pediatric Intensivists and senior Critical Care fellows at Pediatric Critical Care programs were the target population with Transport Medical Directors serving as the expert panel. None. Survey results were scored per Script Concordance Testing guidelines. Concordance within groups was assessed using simple percentage agreement. There was little concordance in decision-making by Transport Medical Directors (median Script Concordance Testing percentage score [interquartile range] of 33.9 [30.4-37.3]). In addition, there was no statistically significant difference between the median Script Concordance Testing scores among the senior fellows and Pediatric Intensivists (31.1 [29.6-33.2] vs 29.7 [28.3-32.3], respectively; p = 0.12). Transport Medical Directors were more concordant on reasoning involving intrinsic patient factors rather than extrinsic factors (10/21 vs 4/24). Our study demonstrates pediatric transport team dispatch decision-making discordance by pediatric critical care physicians of varying levels of expertise and experience. Script Concordance Testing at a local level may better elucidate standards in medical decision-making within

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)

Numerical Modelling and Measurement in a Test Secondary Settling Tank

DEFF Research Database (Denmark)

Dahl, C.; Larsen, Torben; Petersen, O.

1994-01-01

sludge. Phenomena as free and hindered settling and the Bingham plastic characteristic of activated sludge suspensions are included in the numerical model. Further characterisation and test tank experiments are described. The characterisation experiments were designed to measure calibration parameters...... for model description of settling and density differences. In the test tank experiments, flow velocities and suspended sludge concentrations were measured with different tank inlet geomotry and hydraulic and sludge loads. The test tank experiments provided results for the calibration of the numerical model......A numerical model and measurements of flow and settling in activated sludge suspension is presented. The numerical model is an attempt to describe the complex and interrelated hydraulic and sedimentation phenomena by describing the turbulent flow field and the transport/dispersion of suspended...

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

Modeling to Support Groundwater Contaminant Boundaries for the Shoal Underground Nuclear Test

Energy Technology Data Exchange (ETDEWEB)

K. Pohlmann; G. Pohll; J. Chapman; A. Hassan; R. Carroll; C. Shirley

2004-03-01

Groundwater flow and radionuclide transport at the Shoal underground nuclear test are characterized using three-dimensional numerical models, based on site-specific hydrologic data. The objective of this modeling is to provide the flow and transport models needed to develop a contaminant boundary defining the extent of radionuclide-contaminated groundwater at the site throughout 1,000 years at a prescribed level of confidence. This boundary will then be used to manage the Project Shoal Area for the protection of the public and the environment.

A Dual Regime Reactive Transport Model for Simulation of High Level Waste Tank Closure Scenarios - 13375

International Nuclear Information System (INIS)

Sarkar, Sohini; Kosson, David S.; Brown, Kevin; Garrabrants, Andrew C.; Meeussen, Hans; Van der Sloot, Hans

2013-01-01

A numerical simulation framework is presented in this paper for estimating evolution of pH and release of major species from grout within high-level waste tanks after closure. This model was developed as part of the Cementitious Barriers Partnership. The reactive transport model consists of two parts - (1) transport of species, and (2) chemical reactions. The closure grout can be assumed to have varying extents of cracking and composition for performance assessment purposes. The partially or completely degraded grouted tank is idealized as a dual regime system comprising of a mobile region having solid materials with cracks and macro-pores, and an immobile/stagnant region having solid matrix with micropores. The transport profiles of the species are calculated by incorporating advection of species through the mobile region, diffusion of species through the immobile/stagnant region, and exchange of species between the mobile and immobile regions. A geochemical speciation code in conjunction with the pH dependent test data for a grout material is used to obtain a mineral set that best describes the trends in the test data of the major species. The dual regime reactive transport model predictions are compared with the release data from an up-flow column percolation test. The coupled model is then used to assess effects of crack state of the structure, rate and composition of the infiltrating water on the pH evolution at the grout-waste interface. The coupled reactive transport model developed in this work can be used as part of the performance assessment process for evaluating potential risks from leaching of a cracked tank containing elements of human health and environmental concern. (authors)

A Dual Regime Reactive Transport Model for Simulation of High Level Waste Tank Closure Scenarios - 13375

Energy Technology Data Exchange (ETDEWEB)

Sarkar, Sohini; Kosson, David S.; Brown, Kevin; Garrabrants, Andrew C. [Consortium for Risk Assessment with Stakeholder Participation - CRESP, Vanderbilt University, Nashville, TN (United States); Meeussen, Hans [Consortium for Risk Assessment with Stakeholder Participation - CRESP, Nuclear Research and Consultancy Group, Petten (Netherlands); Van der Sloot, Hans [Consortium for Risk Assessment with Stakeholder Participation - CRESP, Hans Van der Sloot Consultancy (Netherlands)

2013-07-01

A numerical simulation framework is presented in this paper for estimating evolution of pH and release of major species from grout within high-level waste tanks after closure. This model was developed as part of the Cementitious Barriers Partnership. The reactive transport model consists of two parts - (1) transport of species, and (2) chemical reactions. The closure grout can be assumed to have varying extents of cracking and composition for performance assessment purposes. The partially or completely degraded grouted tank is idealized as a dual regime system comprising of a mobile region having solid materials with cracks and macro-pores, and an immobile/stagnant region having solid matrix with micropores. The transport profiles of the species are calculated by incorporating advection of species through the mobile region, diffusion of species through the immobile/stagnant region, and exchange of species between the mobile and immobile regions. A geochemical speciation code in conjunction with the pH dependent test data for a grout material is used to obtain a mineral set that best describes the trends in the test data of the major species. The dual regime reactive transport model predictions are compared with the release data from an up-flow column percolation test. The coupled model is then used to assess effects of crack state of the structure, rate and composition of the infiltrating water on the pH evolution at the grout-waste interface. The coupled reactive transport model developed in this work can be used as part of the performance assessment process for evaluating potential risks from leaching of a cracked tank containing elements of human health and environmental concern. (authors)

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...

1/3-scale model testing program

International Nuclear Information System (INIS)

Yoshimura, H.R.; Attaway, S.W.; Bronowski, D.R.; Uncapher, W.L.; Huerta, M.; Abbott, D.G.

1989-01-01

This paper describes the drop testing of a one-third scale model transport cask system. Two casks were supplied by Transnuclear, Inc. (TN) to demonstrate dual purpose shipping/storage casks. These casks will be used to ship spent fuel from DOEs West Valley demonstration project in New York to the Idaho National Engineering Laboratory (INEL) for long term spent fuel dry storage demonstration. As part of the certification process, one-third scale model tests were performed to obtain experimental data. Two 9-m (30-ft) drop tests were conducted on a mass model of the cask body and scaled balsa and redwood filled impact limiters. In the first test, the cask system was tested in an end-on configuration. In the second test, the system was tested in a slap-down configuration where the axis of the cask was oriented at a 10 degree angle with the horizontal. Slap-down occurs for shallow angle drops where the primary impact at one end of the cask is followed by a secondary impact at the other end. The objectives of the testing program were to (1) obtain deceleration and displacement information for the cask and impact limiter system, (2) obtain dynamic force-displacement data for the impact limiters, (3) verify the integrity of the impact limiter retention system, and (4) examine the crush behavior of the limiters. This paper describes both test results in terms of measured deceleration, post test deformation measurements, and the general structural response of the system

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)

Testing of LWR fuel rods to support criticality safety analysis of transport accident conditions

Energy Technology Data Exchange (ETDEWEB)

Purcell, P.C. [BNFL International Transport, Spent Fuel Services (United Kingdom); Dallongeville, M. [COGEMA Logistics (AREVA Group) (France)

2004-07-01

For the transport of low enriched materials, criticality safety may be demonstrated by applying pessimistic modelling assumptions that bound any realistic case. Where Light Water Reactor (LWR) fuel is being transported, enrichment levels are usually too high to permit this approach and more realistic data is needed. This requires a method by which the response of LWR fuel under impact accident conditions can be approximated or bounded. In 2000, BNFL and COGEMA LOGISTICS jointly commenced the Fuel Integrity Project (FIP) whose objective was to develop such methods. COGEMA LOGISTICS were well advanced with a method for determining the impact response of unirradiated fuel, but required further test data before acceptance by the Transport Regulators. The joint project team extensively discussed the required inputs to the FIP, from which it was agreed that BNFL would organise new tests on both unirradiated and irradiated fuel samples and COGEMA LOGISTICS would take major responsibility for evaluating the test results. Tests on unirradiated fuel rod samples involved both dynamic and quasi-static loading on fuel samples. PWR fuel rods loaded with uranium pellets were dropped vertically from 9m onto a rigid target and this was repeated on BWR fuel rods, similar tests on empty fuel rods were also conducted. Quasi-static tests were conducted on 530 mm long PWR and BWR fuel specimens under axial loading. Tests on irradiated fuel samples were conducted on high burn-up fuel rods of both PWR and BWR types. These were believed original to the FIP project and involved applying bending loads to simply supported pressurised rod specimens. In one test the fuel rod was heated to nearly 500oC during loading, all specimens were subject to axial impact before testing. Considerable experience of fuel rod testing and new data was gained from this test programme.

Testing of LWR fuel rods to support criticality safety analysis of transport accident conditions

International Nuclear Information System (INIS)

Purcell, P.C.; Dallongeville, M.

2004-01-01

For the transport of low enriched materials, criticality safety may be demonstrated by applying pessimistic modelling assumptions that bound any realistic case. Where Light Water Reactor (LWR) fuel is being transported, enrichment levels are usually too high to permit this approach and more realistic data is needed. This requires a method by which the response of LWR fuel under impact accident conditions can be approximated or bounded. In 2000, BNFL and COGEMA LOGISTICS jointly commenced the Fuel Integrity Project (FIP) whose objective was to develop such methods. COGEMA LOGISTICS were well advanced with a method for determining the impact response of unirradiated fuel, but required further test data before acceptance by the Transport Regulators. The joint project team extensively discussed the required inputs to the FIP, from which it was agreed that BNFL would organise new tests on both unirradiated and irradiated fuel samples and COGEMA LOGISTICS would take major responsibility for evaluating the test results. Tests on unirradiated fuel rod samples involved both dynamic and quasi-static loading on fuel samples. PWR fuel rods loaded with uranium pellets were dropped vertically from 9m onto a rigid target and this was repeated on BWR fuel rods, similar tests on empty fuel rods were also conducted. Quasi-static tests were conducted on 530 mm long PWR and BWR fuel specimens under axial loading. Tests on irradiated fuel samples were conducted on high burn-up fuel rods of both PWR and BWR types. These were believed original to the FIP project and involved applying bending loads to simply supported pressurised rod specimens. In one test the fuel rod was heated to nearly 500oC during loading, all specimens were subject to axial impact before testing. Considerable experience of fuel rod testing and new data was gained from this test programme

A proposed strategy for the validation of ground-water flow and solute transport models

International Nuclear Information System (INIS)

Davis, P.A.; Goodrich, M.T.

1991-01-01

Ground-water flow and transport models can be thought of as a combination of conceptual and mathematical models and the data that characterize a given system. The judgment of the validity or invalidity of a model depends both on the adequacy of the data and the model structure (i.e., the conceptual and mathematical model). This report proposes a validation strategy for testing both components independently. The strategy is based on the philosophy that a model cannot be proven valid, only invalid or not invalid. In addition, the authors believe that a model should not be judged in absence of its intended purpose. Hence, a flow and transport model may be invalid for one purpose but not invalid for another. 9 refs

A multimedia fate and chemical transport modeling system for pesticides: I. Model development and implementation

International Nuclear Information System (INIS)

Li Rong; Yang Fuquan; Sloan, James J; Scholtz, M Trevor

2011-01-01

We have combined the US EPA MM5/MCIP/SMOKE/CMAQ modeling system with a dynamic soil model, the pesticide emission model (PEM), to create a multimedia chemical transport model capable of describing the important physical and chemical processes involving pesticides in the soil, in the atmosphere, and on the surface of vegetation. These processes include: agricultural practices (e.g. soil tilling and pesticide application mode); advection and diffusion of pesticides, moisture, and heat in the soil; partitioning of pesticides between soil organic carbon and interstitial water and air; emissions from the soil to the atmosphere; gas-particle partitioning and transport in the atmosphere; and atmospheric chemistry and dry and wet deposition of pesticides to terrestrial and water surfaces. The modeling system was tested by simulating toxaphene in a domain that covers most of North America for the period from 1 January 2000 to 31 December 2000. The results show obvious transport of the pesticide from the heavily contaminated soils in the southern United States and Mexico to water bodies including the Atlantic Ocean, the Gulf of Mexico and the Great Lakes, leading to significant dry and wet deposition into these ecosystems. The spatial distributions of dry and wet depositions differ because of their different physical mechanisms; the former follows the distribution of air concentrations whereas the latter is more biased to the North East due to the effect of precipitation.

A multimedia fate and chemical transport modeling system for pesticides: I. Model development and implementation

Energy Technology Data Exchange (ETDEWEB)

Li Rong; Yang Fuquan; Sloan, James J [Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, ON N2L 3G1 (Canada); Scholtz, M Trevor, E-mail: sloanj@connect.uwaterloo.ca [ORTECH Environmental, 2395 Speakman Drive, Mississauga, ON L5K 1B3 (Canada)

2011-07-15

We have combined the US EPA MM5/MCIP/SMOKE/CMAQ modeling system with a dynamic soil model, the pesticide emission model (PEM), to create a multimedia chemical transport model capable of describing the important physical and chemical processes involving pesticides in the soil, in the atmosphere, and on the surface of vegetation. These processes include: agricultural practices (e.g. soil tilling and pesticide application mode); advection and diffusion of pesticides, moisture, and heat in the soil; partitioning of pesticides between soil organic carbon and interstitial water and air; emissions from the soil to the atmosphere; gas-particle partitioning and transport in the atmosphere; and atmospheric chemistry and dry and wet deposition of pesticides to terrestrial and water surfaces. The modeling system was tested by simulating toxaphene in a domain that covers most of North America for the period from 1 January 2000 to 31 December 2000. The results show obvious transport of the pesticide from the heavily contaminated soils in the southern United States and Mexico to water bodies including the Atlantic Ocean, the Gulf of Mexico and the Great Lakes, leading to significant dry and wet deposition into these ecosystems. The spatial distributions of dry and wet depositions differ because of their different physical mechanisms; the former follows the distribution of air concentrations whereas the latter is more biased to the North East due to the effect of precipitation.

A multimedia fate and chemical transport modeling system for pesticides: I. Model development and implementation

Science.gov (United States)

Li, Rong; Scholtz, M. Trevor; Yang, Fuquan; Sloan, James J.

2011-07-01

We have combined the US EPA MM5/MCIP/SMOKE/CMAQ modeling system with a dynamic soil model, the pesticide emission model (PEM), to create a multimedia chemical transport model capable of describing the important physical and chemical processes involving pesticides in the soil, in the atmosphere, and on the surface of vegetation. These processes include: agricultural practices (e.g. soil tilling and pesticide application mode); advection and diffusion of pesticides, moisture, and heat in the soil; partitioning of pesticides between soil organic carbon and interstitial water and air; emissions from the soil to the atmosphere; gas-particle partitioning and transport in the atmosphere; and atmospheric chemistry and dry and wet deposition of pesticides to terrestrial and water surfaces. The modeling system was tested by simulating toxaphene in a domain that covers most of North America for the period from 1 January 2000 to 31 December 2000. The results show obvious transport of the pesticide from the heavily contaminated soils in the southern United States and Mexico to water bodies including the Atlantic Ocean, the Gulf of Mexico and the Great Lakes, leading to significant dry and wet deposition into these ecosystems. The spatial distributions of dry and wet depositions differ because of their different physical mechanisms; the former follows the distribution of air concentrations whereas the latter is more biased to the North East due to the effect of precipitation.

Models for impurity production and transport in tokamaks

International Nuclear Information System (INIS)

Hogan, J.T.

1976-01-01

Models for the edge conditions which are commonly used in tokamak transport codes have been kept simple partly because of a lack of data. A report is presented on an improved model for the particle and energy balance of e - , H 1 + , H 1 0 , H 2 + , H 2 0 , O 0 , O/sup (1 yields 8) + / in the plasma scrape-off region. Experiments should yield the needed data in the near future, and allow one to test the model. The diffusion of impurities has been studied with a neoclassical model. The role of 'anomalous spreading' of the impurity distribution has been studied for the case of Fe. A model is presented for the expulsion of low-Z (oxygen) impurities for cases where q(0) greater than 1, but in which a large shear-free region is produced in the plasma core

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

A computerized coal-water slurry transportation model

Energy Technology Data Exchange (ETDEWEB)

Ljubicic, B.R.; Trostad, B. [Univ. of North Dakota, Grand Forks, ND (United States); Bukurov, Z.; Cvijanovic, P. [Univ. of Novi Sad (Yugoslavia)

1995-12-01

Coal-water fuel (CWF) technology has been developed to the point where full-scale commercialization is just a matter of gaining sufficient market confidence in the price stability of alternate fossil fuels. In order to generalize alternative fuel cost estimates for the desired combinations of processing and/or transportation, a great deal of flexibility is required owing to the understood lack of precision in many of the newly emerging coal technologies. Previously, decisions regarding the sequential and spatial arrangement of the various process steps were made strictly on the basis of experience, simplified analysis, and intuition. Over the last decade, computer modeling has progressed from empirically based correlation to that of intricate mechanistic analysis. Nomograms, charts, tables, and many simple rules of thumb have been made obsolete by the availability of complex computer models. Given the ability to view results graphically in real or near real time, the engineer can immediately verify, from a practical standpoint, whether the initial assumptions and inputs were indeed valid. If the feasibility of a project is being determined in the context of a lack of specific data, the ability to provide a dynamic software-based solution is crucial. Furthermore, the resulting model can be used to establish preliminary operating procedures, test control logic, and train plant/process operators. Presented in this paper is a computerized model capable of estimating the delivered cost of CWF. The model uses coal-specific values, process and transport requirements, terrain factors, and input costs to determine the final operating configuration, bill of materials, and, ultimately, the capital, operating, and unit costs.

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

Particle modeling of transport of α-ray generated ion clusters in air

International Nuclear Information System (INIS)

Tong, Lizhu; Nanbu, Kenichi; Hirata, Yosuke; Izumi, Mikio; Miyamoto, Yasuaki; Yamaguchi, Hiromi

2006-01-01

A particle model is developed using the test-particle Monte Carlo method to study the transport properties of α-ray generated ion clusters in a flow of air. An efficient ion-molecule collision model is proposed to simulate the collisions between ion and air molecule. The simulations are performed for a steady state of ion transport in a circular pipe. In the steady state, generation of ions is balanced with such losses of ions as absorption of the measuring sensor or pipe wall and disappearance by positive-negative ion recombination. The calculated ion current to the measuring sensor agrees well with the previous measured data. (author)

Transportability Testing of the Family of Medium Tactical Vehicles (FMTV) 10-Ton Dump Truck, TP-94-01, Rev. 2, June 2004, "Transportability Testing Procedures"

National Research Council Canada - National Science Library

Barickman, Philip W

2007-01-01

... (FMTV) 10-ton dump truck manufactured by Stewart and Stevenson Systems, Inc., Sealy, Texas. The testing was conducted in accordance with TP-94-01, Revision 2, June 2004 "Transportability Testing Procedures...

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

Experimental and AI-based numerical modeling of contaminant transport in porous media

Science.gov (United States)

Nourani, Vahid; Mousavi, Shahram; Sadikoglu, Fahreddin; Singh, Vijay P.

2017-10-01

This study developed a new hybrid artificial intelligence (AI)-meshless approach for modeling contaminant transport in porous media. The key innovation of the proposed approach is that both black box and physically-based models are combined for modeling contaminant transport. The effectiveness of the approach was evaluated using experimental and real world data. Artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS) were calibrated to predict temporal contaminant concentrations (CCs), and the effect of noisy and de-noised data on the model performance was evaluated. Then, considering the predicted CCs at test points (TPs, in experimental study) and piezometers (in Myandoab plain) as interior conditions, the multiquadric radial basis function (MQ-RBF), as a meshless approach which solves partial differential equation (PDE) of contaminant transport in porous media, was employed to estimate the CC values at any point within the study area where there was no TP or piezometer. Optimal values of the dispersion coefficient in the advection-dispersion PDE and shape coefficient of MQ-RBF were determined using the imperialist competitive algorithm. In temporal contaminant transport modeling, de-noised data enhanced the performance of ANN and ANFIS methods in terms of the determination coefficient, up to 6 and 5%, respectively, in the experimental study and up to 39 and 18%, respectively, in the field study. Results showed that the efficiency of ANFIS-meshless model was more than ANN-meshless model up to 2 and 13% in the experimental and field studies, respectively.

Brittle fracture tests at low temperature for transport cask materials

International Nuclear Information System (INIS)

Kosaki, Akio; Ito, Chihiro; Arai, Taku; Saegusa, Toshiari

1993-01-01

The IAEA Regulations for the Safe Transport of Radioactive Material were revised in 1985, and brittle fracture assessment at low temperature for transport packages are now required. This report discusses the applicability of the actual method for brittle fracture assessment of type-B transport cask materials used in JAPAN. The necessity of brittle fracture assessment at low temperature was estimated for each material of type-B transport casks used in Japan and the applicability was investigated. Dynamic fracture toughness values, K Id (J Id ), and RT NDT values of Low-Mn Carbon Steels, that are SA 350 Gr.LF1 Modify and SA 516 Gr.70 material which used in type-B transport cask body, were also obtained to check whether or not an easier and conventional test method, that prescribed in ASME CODE SECTION III, can be substituted for the dynamic fracture test method. And for bolt materials, which include 1.8Ni-0.8Cr-0.3Mo Carbon Steel and type 630 H Stainless Steel, toughness data were obtained for reference. (J.P.N.)

Evaluation of groundwater flow and transport at the Shoal underground nuclear test: An interim report

International Nuclear Information System (INIS)

Pohll, G.; Chapman, J.; Hassan, A.; Papelis, C.; Andricevic, R.; Shirley, C.

1998-07-01

Since 1962, all United States nuclear tests have been conducted underground. A consequence of this testing has been the deposition of large amounts of radioactive materials in the subsurface, sometimes in direct contact with groundwater. The majority of this testing occurred on the Nevada Test Site, but a limited number of experiments were conducted in other locations. One of these is the subject of this report, the Project Shoal Area (PSA), located about 50 km southeast of Fallon, Nevada. The Shoal test consisted of a 12-kiloton-yield nuclear detonation which occurred on October 26, 1963. Project Shoal was part of studies to enhance seismic detection of underground nuclear tests, in particular, in active earthquake areas. Characterization of groundwater contamination at the Project Shoal Area is being conducted by the US Department of Energy (DOE) under the Federal Facility Agreement and Consent Order (FFACO) with the State of Nevada Department of Environmental Protection and the US Department of Defense (DOD). This order prescribes a Corrective Action Strategy (Appendix VI), which, as applied to underground nuclear tests, involves preparing a Corrective Action Investigation Plan (CAIP), Corrective Action Decision Document (CADD), Corrective Action Plan, and Closure Report. The scope of the CAIP is flow and transport modeling to establish contaminant boundaries that are protective of human health and the environment. This interim report describes the current status of the flow and transport modeling for the PSA

Evaluation of groundwater flow and transport at the Shoal underground nuclear test: An interim report

Energy Technology Data Exchange (ETDEWEB)

Pohll, G.; Chapman, J.; Hassan, A.; Papelis, C.; Andricevic, R.; Shirley, C.

1998-07-01

Since 1962, all United States nuclear tests have been conducted underground. A consequence of this testing has been the deposition of large amounts of radioactive materials in the subsurface, sometimes in direct contact with groundwater. The majority of this testing occurred on the Nevada Test Site, but a limited number of experiments were conducted in other locations. One of these is the subject of this report, the Project Shoal Area (PSA), located about 50 km southeast of Fallon, Nevada. The Shoal test consisted of a 12-kiloton-yield nuclear detonation which occurred on October 26, 1963. Project Shoal was part of studies to enhance seismic detection of underground nuclear tests, in particular, in active earthquake areas. Characterization of groundwater contamination at the Project Shoal Area is being conducted by the US Department of Energy (DOE) under the Federal Facility Agreement and Consent Order (FFACO) with the State of Nevada Department of Environmental Protection and the US Department of Defense (DOD). This order prescribes a Corrective Action Strategy (Appendix VI), which, as applied to underground nuclear tests, involves preparing a Corrective Action Investigation Plan (CAIP), Corrective Action Decision Document (CADD), Corrective Action Plan, and Closure Report. The scope of the CAIP is flow and transport modeling to establish contaminant boundaries that are protective of human health and the environment. This interim report describes the current status of the flow and transport modeling for the PSA.

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

International Nuclear Information System (INIS)

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

2015-01-01

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

Containment performance of transportable storage casks at 9m drop test

Energy Technology Data Exchange (ETDEWEB)

Tobita, H. [Hitachi Zosen Corp., Osaka (Japan); Araki, K. [Hitachi Zosen Diesel and Engineering Co., Ltd., Tokyo (Japan)

2004-07-01

Spent fuel transportable storage casks usually have a double lid closure system, which consists of primary and secondary lids, and gaskets, to keep the containment function during transportation and storage, and to monitor a leakage or containment function during storage. Metal gasket is planning to be used not only during storage but transportation of both before and after storage. As metal gasket will degrade its containment function by creep during storage period of 50 years, relative displacement such as opening and slide displacement between the flange of the containment vessel and the lid should be restricted to a small range. To maintain the containment performance, we provisionally adopted the maximum opening limit of 0.1mm and the maximum slide displacement limit of 3.0mm in the full-scale cask design based on the report of the fundamental experiment on the metal gasket which examines the relation between leakage rate and sealing gap. The purpose of this study is to analyse the behaviour of the sealed parts (lid and vessel body) under 9m-drop impact test conditions and to establish some analytical method to evaluate this behaviour. In this study, the drop test of 1/3scale model of Hitz-B69 cask with the double lids closure system was carried out, the behaviours of the seal part were measured by displacement sensors, and they were compared with the result of the numerical analysis carried out separateley.

Design and Test Space Exploration of Transport-Triggered Architectures

NARCIS (Netherlands)

Zivkovic, V.; Tangelder, R.J.W.T.; Kerkhoff, Hans G.

2000-01-01

This paper describes a new approach in the high level design and test of transport-triggered architectures (TTA), a special type of application specific instruction processors (ASIP). The proposed method introduces the test as an additional constraint, besides throughput and circuit area. The

Aspheric surface testing by irradiance transport equation

Science.gov (United States)

Shomali, Ramin; Darudi, Ahmad; Nasiri, Sadollah; Asgharsharghi Bonab, Armir

2010-10-01

In this paper a method for aspheric surface testing is presented. The method is based on solving the Irradiance Transport Equation (ITE).The accuracy of ITE normally depends on the amount of the pick to valley of the phase distribution. This subject is investigated by a simulation procedure.

Gas transport during in vitro and in vivo preclinical testing of inert gas therapies

Directory of Open Access Journals (Sweden)

Ira Katz

2016-01-01

Full Text Available New gas therapies using inert gases such as xenon and argon are being studied, which require in vitro and in vivo preclinical experiments. Examples of the kinetics of gas transport during such experiments are analyzed in this paper. Using analytical and numerical models, we analyze an in vitro experiment for gas transport to a 96 cell well plate and an in vivo delivery to a small animal chamber, where the key processes considered are the wash-in of test gas into an apparatus dead volume, the diffusion of test gas through the liquid media in a well of a cell test plate, and the pharmacokinetics in a rat. In the case of small animals in a chamber, the key variable controlling the kinetics is the chamber wash-in time constant that is a function of the chamber volume and the gas flow rate. For cells covered by a liquid media the diffusion of gas through the liquid media is the dominant mechanism, such that liquid depth and the gas diffusion constant are the key parameters. The key message from these analyses is that the transport of gas during preclinical experiments can be important in determining the true dose as experienced at the site of action in an animal or to a cell.

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.

The emerging role of transport systems in liver function tests

NARCIS (Netherlands)

Stieger, Bruno; Heger, Michal; de Graaf, Wilmar; Paumgartner, Gustav; van Gulik, Thomas

2012-01-01

Liver function tests are of critical importance for the management of patients with severe or terminal liver disease. They are also used as prognostic tools for planning liver resections. In recent years many transport systems have been identified that also transport substances employed in liver

Plutonium air transportable package Model PAT-1. Safety analysis report

International Nuclear Information System (INIS)

1978-02-01

The document is a Safety Analysis Report for the Plutonium Air Transportable Package, Model PAT-1, which was developed by Sandia Laboratories under contract to the Nuclear Regulatory Commission (NRC). The document describes the engineering tests and evaluations that the NRC staff used as a basis to determine that the package design meets the requirements specified in the NRC ''Qualification Criteria to Certify a Package for Air Transport of Plutonium'' (NUREG-0360). By virtue of its ability to meet the NRC Qualification Criteria, the package design is capable of safely withstanding severe aircraft accidents. The document also includes engineering drawings and specifications for the package. 92 figs, 29 tables

75 FR 38422 - Procedures for Transportation Workplace Drug and Alcohol Testing Programs

Science.gov (United States)

2010-07-02

... 2105-AD84 Procedures for Transportation Workplace Drug and Alcohol Testing Programs AGENCY: Office of..., 2011. DATES: This rule is effective July 2, 2010. FOR FURTHER INFORMATION CONTACT: For program issues... Federal Regulations, as follows: PART 40--PROCEDURES FOR TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING...

Modeling water flow and solute transport in unsaturated zone inside NSRAWD project

International Nuclear Information System (INIS)

Constantin, A.; Diaconu, D.; Bucur, C.; Genty, A.

2015-01-01

The NSRAWD project (2010-2013) - Numerical Simulations for Radioactive Waste Disposal was initiated under a collaboration agreement between the Institute for Nuclear Research and the French Alternative Energies and Atomic Energy Commission (CEA). The context of the project was favorable to combine the modeling activities with an experimental part in order to improve and validate the numerical models used so far to simulate water flow and solute transport at Saligny site, Romania. The numerical models developed in the project were refined and validated on new hydrological data gathered between 2010-2012 by a monitoring station existent on site which performs automatic determination of soil water content and matrix potential, as well as several climate parameters (wind, temperature and precipitations). Water flow and solute transport was modeled in transient conditions, by taking into consideration, as well as neglecting the evapotranspiration phenomenon, on the basis of a tracer test launched on site. The determination of dispersivities for solute transport was targeted from the solute plume. The paper presents the main results achieved in the NSRAWD project related to water flow and solute transport in the unsaturated area of the Saligny site. The results indicated satisfactory predictions for the simulation of water flow in the unsaturated area, in steady state and transient conditions. In the case of tracer transport modeling, dispersivity coefficients could not be finally well fitted for the data measured on site and in order to obtain a realistic preview over the values of these parameters, further investigations are recommended. The article is followed by the slides of the presentation

Towards a realistic approach to validation of reactive transport models for performance assessment

International Nuclear Information System (INIS)

Siegel, M.D.

1993-01-01

Performance assessment calculations are based on geochemical models that assume that interactions among radionuclides, rocks and groundwaters under natural conditions, can be estimated or bound by data obtained from laboratory-scale studies. The data include radionuclide distribution coefficients, measured in saturated batch systems of powdered rocks, and retardation factors measured in short-term column experiments. Traditional approaches to model validation cannot be applied in a straightforward manner to the simple reactive transport models that use these data. An approach to model validation in support of performance assessment is described in this paper. It is based on a recognition of different levels of model validity and is compatible with the requirements of current regulations for high-level waste disposal. Activities that are being carried out in support of this approach include (1) laboratory and numerical experiments to test the validity of important assumptions inherent in current performance assessment methodologies,(2) integrated transport experiments, and (3) development of a robust coupled reaction/transport code for sensitivity analyses using massively parallel computers

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.

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.

Agglomeration of a comprehensive model for the wind-driven sand transport at the Belgian Coast

Science.gov (United States)

Strypsteen, Glenn; Rauwoens, Pieter

2016-04-01

Although a lot of research has been done in the area of Aeolian transport, it is only during the last years that attention has been drawn to Aeolian transport in coastal areas. In these areas, the physical processes are more complex, due to a large number of transport limiting parameters. In this PhD-project, which is now in its early stage, a model will be developed which relates the wind-driven sand transport at the Belgian coast with physical parameters such as the wind speed, humidity and grain size of the sand, and the slope of beach and dune surface. For the first time, the interaction between beach and dune dynamics is studied at the Belgian coast. The Belgian coastline is only 67km long, but densely populated and therefore subject to coastal protection and safety. The coast mostly consists of sandy beaches and dikes. Although, still 33km of dunes exist, whose dynamics are far less understood. The overall research approach consists of three pathways: (i) field measurements, (ii) physical model tests, and (iii) numerical simulations. Firstly and most importantly, several field campaigns will provide accurate data of meteo-marine conditions, morphology, and sand transport events on a wide beach at the Belgian Coastline. The experimental set-up consists of a monitoring station, which will provide time series of vegetation cover, shoreline position, fetch distances, surficial moisture content, wind speed and direction and transport processes. The horizontal and vertical variability of the event scale Aeolian sand transport is analyzed with 8 MWAC sand traps. Two saltiphones register the intensity and variations of grain impacts over time. Two meteo-masts, each with four anemometers and one wind vane, provide quantitative measurements of the wind flow at different locations on the beach. Surficial moisture is measured with a moisture sensor. The topography measurements are typically done with laser techniques. To start, two sites are selected for measurement

Test facilities for radioactive material transport packages (AEA Technology plc, Winfrith,UK)

International Nuclear Information System (INIS)

Gillard, J.E.

2001-01-01

Transport containers for radioactive materials are tested to demonstrate compliance with national and international standards. Transport package design, testing, assessment and approval requires a wide range of skills and facilities. The comprehensive capability of AEA Technology in these areas is described. The facilities described include drop-test cranes and targets (up to 700 tonne); pool fires, furnaces and rigs for thermal tests, including heat dissipation on prototype flasks; shielding facilities; criticality simulations and leak test techniques. These are illustrated with photographs demonstrating the comprehensive nature of package testing services supplied to customers. (author)

Test facilities for radioactive material transport packages (AEA Technology plc, Winfrith,UK)

Energy Technology Data Exchange (ETDEWEB)

Gillard, J.E

2001-07-01

Transport containers for radioactive materials are tested to demonstrate compliance with national and international standards. Transport package design, testing, assessment and approval requires a wide range of skills and facilities. The comprehensive capability of AEA Technology in these areas is described. The facilities described include drop-test cranes and targets (up to 700 tonne); pool fires, furnaces and rigs for thermal tests, including heat dissipation on prototype flasks; shielding facilities; criticality simulations and leak test techniques. These are illustrated with photographs demonstrating the comprehensive nature of package testing services supplied to customers. (author)

Modelling of radionuclide transport in forests: Review and future perspectives

International Nuclear Information System (INIS)

Shaw, G.; Schell, W.; Linkov, I.

1997-01-01

Ecological modeling is a powerful tool which can be used to synthesize information on the dynamic processes which occur in ecosystems. Models of radionuclide transport in forests were first constructed in the mid-1960's, when the consequences of global fallout from nuclear weapons tests and waste disposal in the environment were of great concern. Such models were developed based on site-specific experimental data and were designed to address local needs. These models had a limited applicability in evaluating distinct ecosystems and deposition scenarios. Given the scarcity of information, the same experimental data sets were often used both for model calibration and validation, an approach which clearly constitutes a methodological error. Even though the carry modeling attempts were far from being faultless, they established a useful conceptual approach in that they tried to capture general processes in ecosystems and thus had a holistic nature. Later, radioecological modeling attempted to reveal ecosystem properties by separating the component parts from the whole system, as an approach to simplification. This method worked well for radionuclide transport in agricultural ecosystems, in which the biogeochemistry of radionuclide cycling is relatively well understood and can be influenced by fertilization. Several models have been successfully developed and applied to human dose evaluation and emergency response to contaminating events in agricultural lands

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

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

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

Airline Transport Pilot-Airplane (Air Carrier) Written Test Guide.

Science.gov (United States)

Federal Aviation Administration (DOT), Washington, DC. Flight Standards Service.

Presented is information useful to applicants who are preparing for the Airline Transport Pilot-Airplane (Air Carrier) Written Test. The guide describes the basic aeronautical knowledge and associated requirements for certification, as well as information on source material, instructions for taking the official test, and questions that are…

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)

Electron Temperature Fluctuation Measurements and Transport Model Validation at Alcator C-Mod

Energy Technology Data Exchange (ETDEWEB)

White, Anne [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

2017-06-22

testing and validating predictive models for the transport of heat and particles in fusion plasmas due to turbulence. Once validated, the models are used to predict performance in ITER and other burning plasmas, such as the MIT ARC design. Most recently, data from the newly developed, so-called “CECE diagnostic” [Cima 1995, White 2008] and “nT phase angle measurements” [Haese 1999, White 2010] ]will be combined with data from density fluctuation diagnostics at ASDEX Upgrade to support a long-term program of physics research in turbulence and transport that will allow for more stringent testing and validation of gyrokinetic turbulent-transport codes. This work directly impacts the development of predictive transport models in the U.S. FES program, such as TGLF, developed by General Atomics, which are used to predict performance in ITER and other burning plasma devices as part of advancing the development of fusion energy sciences.

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....

Mechanical Fatigue Testing of High Burnup Fuel for Transportation Applications

Energy Technology Data Exchange (ETDEWEB)

Wang, Jy-An John [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wang, Hong [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2015-05-01

This report describes testing designed to determine the ability of high burnup (HBU) (>45 GWd/MTU) spent fuel to maintain its integrity under normal conditions of transportation. An innovative system, Cyclic Integrated Reversible-bending Fatigue Tester (CIRFT), has been developed at Oak Ridge National Laboratory (ORNL) to test and evaluate the mechanical behavior of spent nuclear fuel (SNF) under conditions relevant to storage and transportation. The CIRFT system is composed of a U-frame equipped with load cells for imposing the pure bending loads on the SNF rod test specimen and measuring the in-situ curvature of the fuel rod during bending using a set up with three linear variable differential transformers (LVDTs).

Mechanical Fatigue Testing of High-Burnup Fuel for Transportation Applications

Energy Technology Data Exchange (ETDEWEB)

Wang, Jy-An John [ORNL; Wang, Hong [ORNL

2015-05-01

This report describes testing designed to determine the ability of high burnup (HBU) (>45 GWd/MTU) spent fuel to maintain its integrity under normal conditions of transportation. An innovative system, Cyclic Integrated Reversible-bending Fatigue Tester (CIRFT), has been developed at Oak Ridge National Laboratory (ORNL) to test and evaluate the mechanical behavior of spent nuclear fuel (SNF) under conditions relevant to storage and transportation. The CIRFT system is composed of a U-frame equipped with load cells for imposing the pure bending loads on the SNF rod test specimen and measuring the in-situ curvature of the fuel rod during bending using a set up with three linear variable differential transformers (LVDTs).

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

Shock Wave Propagation and Gas-Debris Transport into a Vacuum: A Novel Computational Model - TEXAS-NCV

International Nuclear Information System (INIS)

Utschig, Tristan T.; Corradini, Michael L.

2003-01-01

Pulsed power experiments for basic physics investigations as well as inertial confinement fusion designs have developed Z-pinch technologies that produce terawatt level power using multiwire arrays. The energy released from such pulsed power tests results in fragmentation and vaporization of structures at the central wire array as well as shock wave propagation to the chamber boundaries. Practical design and safety considerations require that tracking of this shock front and the associated gas-debris field be done for a variety of experimental configurations to predict the arrival time of hazardous or radioactive debris at fast closure valve locations. A novel computational model has been developed to handle gas expansion into vacuum using a computer model (TEXAS) operating on a Eulerian mesh. Upon expansion of a high-pressure gas into a region of hard vacuum where free molecular transport dominates, the transport model switches between a traditional Eulerian continuum mechanics model and a free molecular transport model across the interface between the two regions. The interface location then propagates along the mesh as the gas expands. This new quasi-one-dimensional model (TEXAS-NCV) has been implemented and tested for two benchmark cases. Such a model can be useful in the design of inertial fusion systems

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

Science.gov (United States)

Xu, Yongbin; Xie, Haihong; Wu, Liuyi

2018-05-01

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

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.

A lattice Boltzmann model for solute transport in open channel flow

Science.gov (United States)

Wang, Hongda; Cater, John; Liu, Haifei; Ding, Xiangyi; Huang, Wei

2018-01-01

A lattice Boltzmann model of advection-dispersion problems in one-dimensional (1D) open channel flows is developed for simulation of solute transport and pollutant concentration. The hydrodynamics are calculated based on a previous lattice Boltzmann approach to solving the 1D Saint-Venant equations (LABSVE). The advection-dispersion model is coupled with the LABSVE using the lattice Boltzmann method. Our research recovers the advection-dispersion equations through the Chapman-Enskog expansion of the lattice Boltzmann equation. The model differs from the existing schemes in two points: (1) the lattice Boltzmann numerical method is adopted to solve the advection-dispersion problem by meso-scopic particle distribution; (2) and the model describes the relation between discharge, cross section area and solute concentration, which increases the applicability of the water quality model in practical engineering. The model is verified using three benchmark tests: (1) instantaneous solute transport within a short distance; (2) 1D point source pollution with constant velocity; (3) 1D point source pollution in a dam break flow. The model is then applied to a 50-year flood point source pollution accident on the Yongding River, which showed good agreement with a MIKE 11 solution and gauging data.

Relevance of IAEA tests to severe accidents in nuclear fuel cycle transport

International Nuclear Information System (INIS)

Wilkinson, W.L.

2004-01-01

The design and performance standards for packages used for the transport of nuclear fuel cycle materials, are defined in the IAEA Regulations for the Safe Transport of Radioactive Materials, TS-R-1, in order to ensure safety under both normal and accident conditions of transport. The underlying philosophy is that safety is vested principally in the package and the design and performance criteria are related to the potential hazard. Type B packages are high duty packages which are used for the transport of the more radioactive materials, notably spent fuel and vitrified high-level waste (VHLW). Tests are specified in the IAEA Regulations to ensure the integrity of these packages in potential transport accidents involving impacts, fires or immersion in water. The mechanical tests for Type B packages include drop tests onto an unyielding surface without giving rise to a significant release of radioactivity. The objects which a package could impact in real life transport accidents, such as concrete roads, bridge abutments and piers, will yield to some extent and absorb some of the energy of the moving package. Impact tests onto an unyielding surface are therefore relevant to impacts onto real-life objects at much higher speeds. The thermal test specifies that Type B packages should be able to withstand a fully engulfing fire of 8000 C for 30 minutes. Analytical studies backed up by experimental tests have shown that these packages can withstand such conditions without significant release of radioactivity. The Regulations also specify immersion tests for Type B packages; 15 metres for 8 hours without significant release of radioactivity and, in addition for spent fuel and VHLW packages, 200 metres for 1 hour without rupture of the containment. Studies have shown that spent fuel and VHLW casks would meet these conditions. Therefore, there is a large body of evidence to show that the current IAEA Type B test requirements are severe and cover all the situations which can

Two dimensional model study of atmospheric transport using carbon-14 and strontium-90 as inert tracers

International Nuclear Information System (INIS)

Kinnison, D.E.; Wuebbles, D.J.; Johnston, H.S.

1992-02-01

This study tests the transport processes in the LLNL two-dimensional chemical-radiative-transport model using recently reanalyzed carbon-14 and strontium-90 data. These radioactive tracers were produced bythe atmospheric nuclear bomb tests of 1952--58 and 1961--62, and they were measured at a few latitudes up to 35 kilometers over the period 1955--1970. Selected horizontal and vertical eddy diffusion coefficients were varied in the model to test their sensitivity to short and long term transpose of carbon-14. A sharp transition of K zz and K yy through the tropopause, as opposed to a slow transition between the same limiting values, shows a distinct improvement in the calculated carbon-14 distributions, a distinct improvement in the calculated seasonal and latitudinal distribution of ozone columns (relative to TOMS observations), and a very large difference in the calculated ozone reduction by a possible fleet of High Speed Civil Transports. Calculated northern hemisphere carbon-14 is more sensitive to variation of K yy than are global ozone columns. Strontium-90 was used to test the LLNL tropopause height at four different latitudes. Starting with the 1960 background distribution of carbon-14, we calculate the input of carbon-14 as the sum of each nuclear test of the 1961--62 series, using two bomb-cloud rise models. With the Seitz bomb-rise formulation in the LLNL model, we find good agreement between calculated and observedcarbon-14 (with noticeable exceptions at the north polar tropopause and the short-term mid-latitude mid-stratosphere) between 1963 and 1970

Test facilities for radioactive material transport packages (AEA Technology, Winfrith, UK)

International Nuclear Information System (INIS)

Burgess, M.H.

1991-01-01

Transport packages for radioactive materials are tested to demonstrate compliance with national and international regulations. The involvement of AEA Technology is traced from the establishment of the early IAEA Regulations. Transport package design, testing, assessment and approval requires a wide variety of skills and facilities. The comprehensive capability of AEA Technology in these areas is described with references to practical experience in the form of a short bibliography. The facilities described include drop-test cranes and targets (up to 700te); air guns for impacts up to sonic velocities; pool fires, furnaces and rigs for thermal tests including heat dissipation on prototype flasks; shielding facilities and instruments; criticality simulations and leak test instruments. These are illustrated with photographs demonstrating the comprehensive nature of package testing services supplied to customers. (author)

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...

Simulating Landscape Sediment Transport Capacity by Using a Modified SWAT Model.

Science.gov (United States)

Bonumá, Nadia B; Rossi, Colleen G; Arnold, Jeffrey G; Reichert, José M; Minella, Jean P; Allen, Peter M; Volk, Martin

2014-01-01

Sediment delivery from hillslopes to rivers is spatially variable and may lead to long-term delays between initial erosion and related sediment yield at the watershed outlet. Consideration of spatial variability is important for developing sound strategies for water quality improvement and soil protection at the watershed scale. Hence, the Soil and Water Assessment Tool (SWAT) was modified and tested in this study to simulate the landscape transport capacity of sediment. The study area was the steeply sloped Arroio Lino watershed in southern Brazil. Observed sediment yield data at the watershed outlet were used to calibrate and validate a modified SWAT model. For the calibration period, the modified model performed better than the unaltered SWAT2009 version; the models achieved Nash-Sutcliffe efficiency (NSE) values of 0.7 and -0.1, respectively. Nash-Sutcliffe efficiencies were less for the validation period, but the modified model's NSE was higher than the unaltered model (-1.4 and -12.1, respectively). Despite the relatively low NSE values, the results of this first test are promising because the model modifications lowered the percent bias in sediment yield from 73 to 18%. Simulation results for the modified model indicated that approximately 60% of the mobilized soil is deposited along the landscape before it reaches the river channels. This research demonstrates the modified model's ability to simulate sediment yield in watersheds with steep slopes. The results suggest that integration of the sediment deposition routine in SWAT increases accuracy in steeper areas while significantly improving its ability to predict the spatial distribution of sediment deposition areas. Further work is needed regarding (i) improved strategies for spatially distributed sediment transport measurements (for improving process knowledge and model evaluation) and (ii) extensive model tests in other well instrumented experimental watersheds with differing topographic configurations

Integrating Norm Activation Model and Theory of Planned Behavior to Understand Sustainable Transport Behavior: Evidence from China.

Science.gov (United States)

Liu, Yuwei; Sheng, Hong; Mundorf, Norbert; Redding, Colleen; Ye, Yinjiao

2017-12-18

With increasing urbanization in China, many cities are facing serious environmental problems due to continuous and substantial increase in automobile transportation. It is becoming imperative to examine effective ways to reduce individual automobile use to facilitate sustainable transportation behavior. Empirical, theory-based research on sustainable transportation in China is limited. In this research, we propose an integrated model based on the norm activation model and the theory of planned behavior by combining normative and rational factors to predict individuals' intention to reduce car use. Data from a survey of 600 car drivers in China's three metropolitan areas was used to test the proposed model and hypotheses. Results showed that three variables, perceived norm of car-transport reduction, attitude towards reduction, and perceived behavior control over car-transport reduction, significantly affected the intention to reduce car-transport. Personal norms mediated the relationship between awareness of consequences of car-transport, ascription of responsibility of car-transport, perceived subjective norm for car-transport reduction, and intention to reduce car-transport. The results of this research not only contribute to theory development in the area of sustainable transportation behavior, but also provide a theoretical frame of reference for relevant policy-makers in urban transport management.

Integrating Norm Activation Model and Theory of Planned Behavior to Understand Sustainable Transport Behavior: Evidence from China

Directory of Open Access Journals (Sweden)

Yuwei Liu

2017-12-01

Full Text Available With increasing urbanization in China, many cities are facing serious environmental problems due to continuous and substantial increase in automobile transportation. It is becoming imperative to examine effective ways to reduce individual automobile use to facilitate sustainable transportation behavior. Empirical, theory-based research on sustainable transportation in China is limited. In this research, we propose an integrated model based on the norm activation model and the theory of planned behavior by combining normative and rational factors to predict individuals’ intention to reduce car use. Data from a survey of 600 car drivers in China’s three metropolitan areas was used to test the proposed model and hypotheses. Results showed that three variables, perceived norm of car-transport reduction, attitude towards reduction, and perceived behavior control over car-transport reduction, significantly affected the intention to reduce car-transport. Personal norms mediated the relationship between awareness of consequences of car-transport, ascription of responsibility of car-transport, perceived subjective norm for car-transport reduction, and intention to reduce car-transport. The results of this research not only contribute to theory development in the area of sustainable transportation behavior, but also provide a theoretical frame of reference for relevant policy-makers in urban transport management.

Assessment of hydrologic transport of radionuclides from the Gasbuggy underground nuclear test site, New Mexico

International Nuclear Information System (INIS)

Earman, S.; Chapman, J.; Andricevic, R.

1996-09-01

The U.S. Department of Energy (DOE) is operating an environmental restoration program to characterize, remediate, and close non-Nevada Test Site locations that were used for nuclear testing. Evaluation of radionuclide transport by groundwater from these sites is an important part of the preliminary risk analysis. These evaluations are undertaken to allow prioritization of the test areas in terms of risk, provide a quantitative basis for discussions with regulators and the public about future work at the sites, and provide a framework for assessing data needs to be filled by site characterization. The Gasbuggy site in northwestern New Mexico was the location of an underground detonation of a 29-kiloton nuclear device in 1967. The test took place in the Lewis Shale, approximately 182 m below the Ojo Alamo Sandstone, which is the aquifer closest to the detonation horizon. The conservative assumption was made that tritium was injected from the blast-created cavity into the Ojo Alamo Sandstone by the force of the explosion, via fractures created by the shot. Model results suggest that if radionuclides produced by the shot entered the Ojo Alamo, they are most likely contained within the area currently administered by DOE. The transport calculations are most sensitive to changes in the mean groundwater velocity, followed by the variance in hydraulic conductivity, the correlation scale of hydraulic conductivity, the transverse hydrodynamic dispersion coefficient, and uncertainty in the source size. This modeling was performed to investigate how the uncertainty in various physical parameters affects calculations of radionuclide transport at the Gasbuggy site, and to serve as a starting point for discussion regarding further investigation at the site; it was not intended to be a definitive simulation of migration pathways or radionuclide concentration values

75 FR 59105 - Procedures for Transportation Workplace Drug and Alcohol Testing Programs: Federal Drug Testing...

Science.gov (United States)

2010-09-27

... 2105-AE03 Procedures for Transportation Workplace Drug and Alcohol Testing Programs: Federal Drug... the Federal workplace drug testing program but also pointed out that ``* * * the Department of.... Executive Order 12866 and Regulatory Flexibility Act This Interim Final Rule is not significant for purposes...

Modelling of transport and biogeochemical processes in pollution plumes: Literature review of model development

DEFF Research Database (Denmark)

Brun, A.; Engesgaard, Peter Knudegaard

2002-01-01

A literature survey shows how biogeochemical (coupled organic and inorganic reaction processes) transport models are based on considering the complete biodegradation process as either a single- or as a two-step process. It is demonstrated that some two-step process models rely on the Partial...... Equilibrium Approach (PEA). The PEA assumes the organic degradation step, and not the electron acceptor consumption step, is rate limiting. This distinction is not possible in one-step process models, where consumption of both the electron donor and acceptor are treated kinetically. A three-dimensional, two......-step PEA model is developed. The model allows for Monod kinetics and biomass growth, features usually included only in one-step process models. The biogeochemical part of the model is tested for a batch system with degradation of organic matter under the consumption of a sequence of electron acceptors...

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

Vapor Transport Through Fractures and Other High-Permeability Paths: Its Role in the Drift Scale Test at Yucca Mountain, Nevada

Science.gov (United States)

Mukhopadhyay, S.; Tsang, Y. W.

2001-12-01

-permeability wing heater boreholes and escapes the test block through an open bulkhead that connects the HD to the outside world. We show that this vapor transport makes a significant difference in the validation of numerical models against TH processes in the DST. A huge volume of data, including changes in temperature and saturation of the rock, has been collected from the DST. Sophisticated conceptual and numerical models, based on the TOUGH2 simulator, have been developed to analyze these data and to help develop a better understanding of various aspects of coupled TH processes in unsaturated fractured tuff. In general, these models have predicted a close match between measured and simulated results, indicating a good representation of the underlying physical processes. However, there are subtle differences in the predictions from these models. Of particular interest here are two models: One in which vapor transport was considered through the natural fractures only, and the other in which vapor transport through the boreholes housing the wing heaters was included in addition to that through natural fractures. Direct statistical comparison of simulated and measured temperatures from more than 1,700 sensors yielded a mean error of 3-4oC for the first model, indicating that less heat was retained in the test block than that predicted by the model. On the other hand, a similar statistical comparison yielded a mean error of 1-2oC for the second model, suggesting that inclusion of vapor loss through the boreholes produces results closer to the measured data.

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

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

Flight Test of L1 Adaptive Control Law: Offset Landings and Large Flight Envelope Modeling Work

Science.gov (United States)

Gregory, Irene M.; Xargay, Enric; Cao, Chengyu; Hovakimyan, Naira

2011-01-01

This paper presents new results of a flight test of the L1 adaptive control architecture designed to directly compensate for significant uncertain cross-coupling in nonlinear systems. The flight test was conducted on the subscale turbine powered Generic Transport Model that is an integral part of the Airborne Subscale Transport Aircraft Research system at the NASA Langley Research Center. The results presented include control law evaluation for piloted offset landing tasks as well as results in support of nonlinear aerodynamic modeling and real-time dynamic modeling of the departure-prone edges of the flight envelope.

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

Constraining performance assessment models with tracer test results: a comparison between two conceptual models

Science.gov (United States)

McKenna, Sean A.; Selroos, Jan-Olof

Tracer tests are conducted to ascertain solute transport parameters of a single rock feature over a 5-m transport pathway. Two different conceptualizations of double-porosity solute transport provide estimates of the tracer breakthrough curves. One of the conceptualizations (single-rate) employs a single effective diffusion coefficient in a matrix with infinite penetration depth. However, the tracer retention between different flow paths can vary as the ratio of flow-wetted surface to flow rate differs between the path lines. The other conceptualization (multirate) employs a continuous distribution of multiple diffusion rate coefficients in a matrix with variable, yet finite, capacity. Application of these two models with the parameters estimated on the tracer test breakthrough curves produces transport results that differ by orders of magnitude in peak concentration and time to peak concentration at the performance assessment (PA) time and length scales (100,000 years and 1,000 m). These differences are examined by calculating the time limits for the diffusive capacity to act as an infinite medium. These limits are compared across both conceptual models and also against characteristic times for diffusion at both the tracer test and PA scales. Additionally, the differences between the models are examined by re-estimating parameters for the multirate model from the traditional double-porosity model results at the PA scale. Results indicate that for each model the amount of the diffusive capacity that acts as an infinite medium over the specified time scale explains the differences between the model results and that tracer tests alone cannot provide reliable estimates of transport parameters for the PA scale. Results of Monte Carlo runs of the transport models with varying travel times and path lengths show consistent results between models and suggest that the variation in flow-wetted surface to flow rate along path lines is insignificant relative to variability in

Qualification test of packages for transporting radioactive materials and wastes

International Nuclear Information System (INIS)

Oliveira Santos, P. de; Miaw, S.T.W.

1990-01-01

Since 1979 the Waste Treatment Division of Nuclear Tecnology Development Center has been developed and tested packagings for transporting radioactive materials and wastes. The Division has designed facilities for testing Type A packages in accordance with the adopted regulations. The Division has tested several packages for universities, research centers, industries, INB, FURNAS, etc. (author) [pt

Modeling to Support Groundwater Contaminant Boundaries for the Shoal Underground Nuclear Test

Energy Technology Data Exchange (ETDEWEB)

K. Pohlmann; G. Pohll; J. Chapman; A. Hassan; R. Carroll; C. Shirley

2004-03-01

The purpose of this work is to characterize groundwater flow and contaminant transport at the Shoal underground nuclear test through numerical modeling using site-specific hydrologic data. The ultimate objective is the development of a contaminant boundary, a model-predicted perimeter defining the extent of radionuclide-contaminated groundwater from the underground test throughout 1,000 years at a prescribed level of confidence. This boundary will be developed using the numerical models described here, after they are approved for that purpose by DOE and NDEP.