WorldWideScience

Sample records for contaminant transport experimental

  1. 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.

  2. Experimental investigation of airborne contaminant transport by a human wake moving in a ventilated aircraft cabin

    Science.gov (United States)

    Poussou, Stephane B.

    The air ventilation system in jetliners provides a comfortable and healthy environment for passengers. Unfortunately, the increase in global air traffic has amplified the risks presented by infectious aerosols or noxious material released during flight. Inside the cabin, air typically flows continuously from overhead outlets into sidewall exhausts in a circular pattern that minimizes secondary flow between adjacent seat rows. However, disturbances frequently introduced by individuals walking along an aisle may alter air distribution, and contribute to spreading of contaminants. Numerical simulation of these convoluted transient flow phenomena is difficult and complex, and experimental assessment of contaminant distribution in real cabins often impractical. A fundamental experimental study was undertaken to examine the transport phenomena, to validate computations and to improve air monitoring systems. A finite moving body was modeled in a 10:1 scale simplified aircraft cabin equipped with ventilation, at a Reynolds number (based on body diameter) of the order of 10,000. An experimental facility was designed and constructed to permit measurements of the ventilation and wake velocity fields using particle image velocimetry (PIV). Contaminant migration was imaged using the planar laser induced fluorescence (PLIF) technique. The effect of ventilation was estimated by comparison with a companion baseline study. Results indicate that the evolution of a downwash predominant behind finite bodies of small aspect ratio is profoundly perturbed by the ventilation flow. The reorganization of vortical structures in the near-wake leads to a shorter longitudinal recirculation region. Furthermore, mixing in the wake is modified and contaminant is observed to convect to higher vertical locations corresponding to seated passenger breathing level.

  3. Transportation cask contamination weeping

    International Nuclear Information System (INIS)

    Bennett, P.C.; Doughty, D.H.; Chambers, W.B.

    1993-01-01

    This paper describes the problem of cask contamination weeping, and efforts to understand the phenomenon and to eliminate its occurrence during spent nuclear fuel transport. The paper summarizes analyses of field experience and scoping experiments, and concentrates on current modelling and experimental validation efforts. (J.P.N.)

  4. Experimental Model of Contaminant Transport by a Moving Wake Inside an Aircraft Cabin

    Science.gov (United States)

    Poussou, Stephane; Sojka, Paul; Plesniak, Michael

    2008-11-01

    The air cabin environment in jetliners is designed to provide comfortable and healthy conditions for passengers. The air ventilation system produces a recirculating pattern designed to minimize secondary flow between seat rows. However, disturbances are frequently introduced by individuals walking along the aisle and may significantly modify air distribution and quality. Spreading of infectious aerosols or biochemical agents presents potential health hazards. A fundamental study has been undertaken to understand the unsteady transport phenomena, to validate numerical simulations and to improve air monitoring systems. A finite moving body is modeled experimentally in a 10:1 scale simplified aircraft cabin equipped with ventilation, at a Reynolds number (based on body height) of the order of 10,000. Measurements of the ventilation and wake velocity fields are obtained using PIV and PLIF. Results indicate that the evolution of the typical downwash behind the body is profoundly perturbed by the ventilation flow. Furthermore, the interaction between wake and ventilation flow significantly alters scalar contaminant migration.

  5. Monitoring of transport contamination

    International Nuclear Information System (INIS)

    Turkin, N.F.

    1980-01-01

    Organization of monitoring of transport contamination is considered. A particularly thorough monitoring is recommended to be carried out in loading-unloading operations. The monitoring is performed when leaving loading-unloading site and zone under control and prior to preventive examination, technical service or repair. The method of monitoring of auto transport contamination with high-energy β-emitters by means of a special stand permitting the automation of the monitoring process is described [ru

  6. Comparison of Experimental Methods for Estimating Matrix Diffusion Coefficients for Contaminant Transport Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Telfeyan, Katherine Christina [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ware, Stuart Douglas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reimus, Paul William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Birdsell, Kay Hanson [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-11-06

    Diffusion cell and diffusion wafer experiments were conducted to compare methods for estimating matrix diffusion coefficients in rock core samples from Pahute Mesa at the Nevada Nuclear Security Site (NNSS). A diffusion wafer method, in which a solute diffuses out of a rock matrix that is pre-saturated with water containing the solute, is presented as a simpler alternative to the traditional through-diffusion (diffusion cell) method. Both methods yielded estimates of matrix diffusion coefficients that were within the range of values previously reported for NNSS volcanic rocks. The difference between the estimates of the two methods ranged from 14 to 30%, and there was no systematic high or low bias of one method relative to the other. From a transport modeling perspective, these differences are relatively minor when one considers that other variables (e.g., fracture apertures, fracture spacings) influence matrix diffusion to a greater degree and tend to have greater uncertainty than diffusion coefficients. For the same relative random errors in concentration measurements, the diffusion cell method yields diffusion coefficient estimates that have less uncertainty than the wafer method. However, the wafer method is easier and less costly to implement and yields estimates more quickly, thus allowing a greater number of samples to be analyzed for the same cost and time. Given the relatively good agreement between the methods, and the lack of any apparent bias between the methods, the diffusion wafer method appears to offer advantages over the diffusion cell method if better statistical representation of a given set of rock samples is desired.

  7. Comparison of experimental methods for estimating matrix diffusion coefficients for contaminant transport modeling

    Science.gov (United States)

    Telfeyan, Katherine; Ware, S. Doug; Reimus, Paul W.; Birdsell, Kay H.

    2018-02-01

    Diffusion cell and diffusion wafer experiments were conducted to compare methods for estimating effective matrix diffusion coefficients in rock core samples from Pahute Mesa at the Nevada Nuclear Security Site (NNSS). A diffusion wafer method, in which a solute diffuses out of a rock matrix that is pre-saturated with water containing the solute, is presented as a simpler alternative to the traditional through-diffusion (diffusion cell) method. Both methods yielded estimates of effective matrix diffusion coefficients that were within the range of values previously reported for NNSS volcanic rocks. The difference between the estimates of the two methods ranged from 14 to 30%, and there was no systematic high or low bias of one method relative to the other. From a transport modeling perspective, these differences are relatively minor when one considers that other variables (e.g., fracture apertures, fracture spacings) influence matrix diffusion to a greater degree and tend to have greater uncertainty than effective matrix diffusion coefficients. For the same relative random errors in concentration measurements, the diffusion cell method yields effective matrix diffusion coefficient estimates that have less uncertainty than the wafer method. However, the wafer method is easier and less costly to implement and yields estimates more quickly, thus allowing a greater number of samples to be analyzed for the same cost and time. Given the relatively good agreement between the methods, and the lack of any apparent bias between the methods, the diffusion wafer method appears to offer advantages over the diffusion cell method if better statistical representation of a given set of rock samples is desired.

  8. Contaminated sediment transport during floods

    International Nuclear Information System (INIS)

    Fontaine, T.A.

    1992-01-01

    Over the past 48 years, operations and waste disposal activities at Oak Ridge National Laboratory have resulted in the contamination of parts of the White Oak Creek catchment. The contaminants presenting the highest risk to human health and the environment are particle reactive and are associated with the soils and sediments in the White Oak Creek drainage system. The erosion of these sediments during floods can result in the transport of contaminants both within the catchment and off-site into the Clinch River. A data collection program and a modeling investigation are being used to evaluate the probability of contaminated sediment transport during floods and to develop strategies for controlling off-site transport under present and future conditions

  9. 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.)

  10. Contaminant transport in Massachusetts Bay

    Science.gov (United States)

    Butman, Bradford

    Construction of a new treatment plant and outfall to clean up Boston Harbor is currently one of the world's largest public works projects, costing about $4 billion. There is concern about the long-term impact of contaminants on Massachusetts Bay and adjacent Gulf of Maine because these areas are used extensively for transportation, recreation, fishing, and tourism, as well as waste disposal. Public concern also focuses on Stellwagen Bank, located on the eastern side of Massachusetts Bay, which is an important habitat for endangered whales. Contaminants reach Massachusetts Bay not only from Boston Harbor, but from other coastal communities on the Gulf of Maine, as well as from the atmosphere. Knowledge of the pathways, mechanisms, and rates at which pollutants are transported throughout these coastal environments is needed to address a wide range of management questions.

  11. Experimental constraints on transport

    International Nuclear Information System (INIS)

    Luce, T.C.; Petty, K.H.; Burrell, K.H.; Forest, C.B.; Gohil, P.; Groebner, R.J.; De Haas, J.C.M.; James, R.A.; Makowski, M.A.

    1994-12-01

    Characterization of the cross-field energy transport in magnetic confinement experiments in a manner applicable to the accurate assessment of future machine performance continues to be a challenging goal. Experimental results from the DIII-D tokamak in the areas of dimensionless scaling and non-diffusive transport represent progress toward this goal. Dimensionless scaling shows how beneficial the increase in machine size and magnetic field is for future devices. The experiments on DIII-D are the first to determine separately the electron and ion scaling with normalized gyroradius ρ * ; the electrons scale as expected from gyro-Bohm class theories, while the ions scale consistent with the Goldston empirical scaling. This result predicts an increase in transport relative to Bohm diffusion as ρ * decreases in future devices. The existence of distinct ρ * scalings for ions and electrons cautions against a physical interpretation of one-fluid or global analysis. The second class of experiments reported here are the first to demonstrate the existence of non-diffusive energy transport. Electron cyclotron heating was applied at the half radius; the electron temperature profile remains substantially peaked. Power balance analysis indicates that heat must flow in the direction of increasing temperature, which is inconsistent with purely diffusive transport. The dynamics of electron temperature perturbations indicate the presence in the heat flux of a term dependent on temperature rather than its gradient. These two observations strongly constrain the types of models which can be applied to cross-field heat transport

  12. 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...

  13. Contaminant transport at a waste residue deposit

    DEFF Research Database (Denmark)

    Engesgaard, Peter Knudegaard; Traberg, Rikke

    1996-01-01

    Contaminant transport in an aquifer at an incinerator waste residue deposit in Denmark is simulated. A two-dimensional, geochemical transport code is developed for this purpose and tested by comparison to results from another code, The code is applied to a column experiment and to the field site...

  14. Analytical methods for predicting contaminant transport

    International Nuclear Information System (INIS)

    Pigford, T.H.

    1989-09-01

    This paper summarizes some of the previous and recent work at the University of California on analytical solutions for predicting contaminate transport in porous and fractured geologic media. Emphasis is given here to the theories for predicting near-field transport, needed to derive the time-dependent source term for predicting far-field transport and overall repository performance. New theories summarized include solubility-limited release rate with flow backfill in rock, near-field transport of radioactive decay chains, interactive transport of colloid and solute, transport of carbon-14 as carbon dioxide in unsaturated rock, and flow of gases out of and a waste container through cracks and penetrations. 28 refs., 4 figs

  15. Nonisothermal hydrologic transport experimental plan

    International Nuclear Information System (INIS)

    Rasmussen, T.C.; Evans, D.D.

    1992-09-01

    A field heater experimental plan is presented for investigating hydrologic transport processes in unsaturated fractured rock related to the disposal of high-level radioactive waste (HLW) in an underground repository. The experimental plan provides a methodology for obtaining data required for evaluating conceptual and computer models related to HLW isolation in an environment where significant heat energy is produced. Coupled-process models are currently limited by the lack of validation data appropriate for field scales that incorporate relevant transport processes. Presented in this document is a discussion of previous nonisothermal experiments. Processes expected to dominate heat-driven liquid, vapor, gas, and solute flow during the experiment are explained, and the conceptual model for nonisothermal flow and transport in unsaturated, fractured rock is described. Of particular concern is the ability to confirm the hypothesized conceptual model specifically, the establishment of higher water saturation zones within the host rock around the heat source, and the establishment of countercurrent flow conditions within the host rock near the heat source. Field experimental plans are presented using the Apache Leap Tuff Site to illustrate the implementation of the proposed methodology. Both small-scale preliminary experiments and a long-term experiment are described

  16. A study on contaminant transport in indoor air

    International Nuclear Information System (INIS)

    Pujala, Usha; Sen, Soubhadra; Subramanian, V.; Srinivas, C.V.; Baskaran, R.; Venkatraman, B.

    2016-01-01

    In case of an accidental release of radioactive contaminant inside a well-ventilated room, the same will be transported to the different parts of the room due to the circulation of indoor air. To ensure safety of the operating personnel, it is important to identify the ideal locations for keeping the warning alarm systems. To address the problem, a detailed study is required where numerical simulation has to be supported by experimental verification. A computational methodology has already been verified for this purpose (IGC report-no.323). In this work, a study on the transport of an inert aerosol inside a well-ventilated isolated room has been carried out

  17. Flow and contaminant transport in fractured rocks

    International Nuclear Information System (INIS)

    Bear, J.; Tsang, C.F.; Marsily, G. de

    1993-01-01

    This book is a compilation of nine articles dealing with various aspect of flow in fractured media. Articles range from radionuclide waste to multiphase flow in petroleum reservoirs to practical field test methods. Each chapter contains copious figures to aid the reader, but is also a detailed in-depth analysis of some major flow problem. The subjects covered are as follows: an introduction to flow and transport models; solute transport in fractured rock with application to radioactive waste repositories; solute transport models through fractured networks; theoretical view of stochastic models of fracture systems; numerical models of tracers; multiphase flow models in fractured systems and petroleum reservoirs; unsaturated flow modeling; comparative analysis of various flow modeling techniques in fractured media; and, a summary of field methods for measuring transfers of mass, heat, contaminant, momentum, and electrical charge in fractured media

  18. Intermediate-field transport of contaminants

    International Nuclear Information System (INIS)

    Ahn, J.; Kim, C.L.; Chambre, P.L.; Pigford, T.H.; Lee, W.W.L.

    1989-06-01

    This report is about ''intermediate-field'' transport or the migration of contaminants from arrays of discrete waste packages or sources. In constructing nuclear waste repositories in rock, it may be necessary to place a waste package across a rock fracture, or a rock fracture may develop some time after waste packages have been emplaced. To predict the spatial and temporal distribution of contaminant species from a line of waste packages facing a rock fracture may be important, because such fractures may now be considered a preferential pathway for released radionuclides to re-enter the biosphere. In land disposal of hazardous wastes, individual barrels may contain especially toxic material whose dispersion special attention. We have published analytic solutions for the multidimensional advective transport of contaminants from arrays of waste packages and multiple areal sources into a planar fracture. The results show a near region in which the concentrations vary greatly in the direction transverse to ground-water flow, an intermediate region in which the array can be treated as an infinite plane source of dissolving species, and a far-field region in which the array can be treated as a plane source of finite extent. The array equations have been developed for both porous and fractured media. In this paper we summarize and compare the work with multiple areal sources facing a planar fracture and an array of point sources in porous media. 5 refs., 5 figs

  19. In-stream contaminant interaction and transport

    International Nuclear Information System (INIS)

    Whelan, G.

    1983-07-01

    In order to assess contaminant exposure levels in biotic and abiotic pathways from waste-disposal sites, a comprehensive Multimedia Contaminant Environmental Exposure Assessment (MCEA) methodology using several mathematical models is being developed. Prior to a full development of the proposed methodology, a scaled-down version involving terrestrial plants, overland, and in-stream compartments was applied to an actual shallow land waste-disposal site. The purpose was to evaluate and demonstrate the attributes of the methodology. The in-stream component of the abbreviated methodology as it relates to Mortandad Canyon in Los Alamos, New Mexico is discussed herein. A two-year period was simulated consisting of six major runoff events which possessed a variety of distributions and magnitudes. The in-stream component of the methodology was composed of two models integrated to simulate the migration of radionuclides: DKWAV and TODAM. DKWAV is an unsteady, one-dimensional, second-order, explicit, finite difference, channel flow code which simulates the hydrodynamics in dendritric river systems and includes point and/or continuous lateral inflow and channel seepage. TODAM is an unsteady, one-dimensional, finite element, sediment-contaminant transport code which simulates the migration and fate of sediment and radionuclides in their dissolved and particulate phases by solving the general advection/diffusion equation with sink and source terms

  20. Low-Rank Kalman Filtering in Subsurface Contaminant Transport Models

    KAUST Repository

    El Gharamti, Mohamad

    2010-12-01

    Understanding the geology and the hydrology of the subsurface is important to model the fluid flow and the behavior of the contaminant. It is essential to have an accurate knowledge of the movement of the contaminants in the porous media in order to track them and later extract them from the aquifer. A two-dimensional flow model is studied and then applied on a linear contaminant transport model in the same porous medium. Because of possible different sources of uncertainties, the deterministic model by itself cannot give exact estimations for the future contaminant state. Incorporating observations in the model can guide it to the true state. This is usually done using the Kalman filter (KF) when the system is linear and the extended Kalman filter (EKF) when the system is nonlinear. To overcome the high computational cost required by the KF, we use the singular evolutive Kalman filter (SEKF) and the singular evolutive extended Kalman filter (SEEKF) approximations of the KF operating with low-rank covariance matrices. The SEKF can be implemented on large dimensional contaminant problems while the usage of the KF is not possible. Experimental results show that with perfect and imperfect models, the low rank filters can provide as much accurate estimates as the full KF but at much less computational cost. Localization can help the filter analysis as long as there are enough neighborhood data to the point being analyzed. Estimating the permeabilities of the aquifer is successfully tackled using both the EKF and the SEEKF.

  1. Low-Rank Kalman Filtering in Subsurface Contaminant Transport Models

    KAUST Repository

    El Gharamti, Mohamad

    2010-01-01

    Understanding the geology and the hydrology of the subsurface is important to model the fluid flow and the behavior of the contaminant. It is essential to have an accurate knowledge of the movement of the contaminants in the porous media in order to track them and later extract them from the aquifer. A two-dimensional flow model is studied and then applied on a linear contaminant transport model in the same porous medium. Because of possible different sources of uncertainties, the deterministic model by itself cannot give exact estimations for the future contaminant state. Incorporating observations in the model can guide it to the true state. This is usually done using the Kalman filter (KF) when the system is linear and the extended Kalman filter (EKF) when the system is nonlinear. To overcome the high computational cost required by the KF, we use the singular evolutive Kalman filter (SEKF) and the singular evolutive extended Kalman filter (SEEKF) approximations of the KF operating with low-rank covariance matrices. The SEKF can be implemented on large dimensional contaminant problems while the usage of the KF is not possible. Experimental results show that with perfect and imperfect models, the low rank filters can provide as much accurate estimates as the full KF but at much less computational cost. Localization can help the filter analysis as long as there are enough neighborhood data to the point being analyzed. Estimating the permeabilities of the aquifer is successfully tackled using both the EKF and the SEEKF.

  2. Packaging and transportation of radioactively contaminated lead

    International Nuclear Information System (INIS)

    Gleason, Eugene; Holden, Gerard

    2007-01-01

    Under the management of the Nuclear Decommissioning Authority (NDA) the government of the United Kingdom has launched an ambitious program to remediate the nation's nuclear waste legacy. Over a twenty-five year period NDA plans to decommission several first generation nuclear power plants and other radioactive facilities. The use innovative, safe 'fit for purpose' technologies will be a major part of this complex program. This paper will present a case study of a recently completed project undertaken in support of the nuclear decommissioning activities at the Sellafield site in the United Kingdom. The focus is on an innovative application of new packaging technology developed for the safe transportation of radioactively contaminated lead objects. Several companies collaborated on the project and contributed to its safe and successful conclusion. These companies include British Nuclear Group, Gravatom Engineering, W. F. Bowker Transport, Atlantic Container Lines, MHF Logistical Solutions and Energy Solutions. New containers and a new innovative inter-modal packaging system to transport the radioactive lead were developed and demonstrated during the project. The project also demonstrated the potential contribution of international nuclear recycling activities as a safe, economic and feasible technical option for nuclear decommissioning in the United Kingdom. (authors)

  3. Lesions in Broiler Chicks Following Experimental Contamination ...

    African Journals Online (AJOL)

    SH

    Average daily food intake (ADFI), average daily gain (ADG), and ... that contamination of feed for broilers chicks beyond 0.5% is detrimental to the performance of broiler chicks. Introduction ... nearly all manufacturing industries. Disposal of ...

  4. Contaminant transport modeling studies of Russian sites

    International Nuclear Information System (INIS)

    Tsang, Chin-Fu

    1993-01-01

    Lawrence Berkeley Laboratory (LBL) established mechanisms that promoted cooperation between U.S. and Russian scientists in scientific research as well as environmental technology transfer. Using Russian experience and U.S technology, LBL developed approaches for field investigations, site evaluation, waste disposal, and remediation at Russian contaminated sites. LBL assessed a comprehensive database as well as an actual, large-scale contaminated site to evaluate existing knowledge of and test mathematical models used for the assessment of U.S. contaminated sites

  5. Lesions in Broiler Chicks Following Experimental Contamination ...

    African Journals Online (AJOL)

    The objective of the present study was to investigate the effect of feed contamination with battery waste on the performance, organs weights as well as the histology of some internal organs of broiler chicks. A total of 120 1- d old broiler chicks were allotted to four dietary treatments in a completely randomized design.

  6. 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

  7. Evaluation of soil flushing of complex contaminated soil: An experimental and modeling simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Sung Mi; Kang, Christina S. [Department of Environmental Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143-701 (Korea, Republic of); Kim, Jonghwa [Department of Industrial Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143-701 (Korea, Republic of); Kim, Han S., E-mail: hankim@konkuk.ac.kr [Department of Environmental Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143-701 (Korea, Republic of)

    2015-04-28

    Highlights: • Remediation of complex contaminated soil achieved by sequential soil flushing. • Removal of Zn, Pb, and heavy petroleum oils using 0.05 M citric acid and 2% SDS. • Unified desorption distribution coefficients modeled and experimentally determined. • Nonequilibrium models for the transport behavior of complex contaminants in soils. - Abstract: The removal of heavy metals (Zn and Pb) and heavy petroleum oils (HPOs) from a soil with complex contamination was examined by soil flushing. Desorption and transport behaviors of the complex contaminants were assessed by batch and continuous flow reactor experiments and through modeling simulations. Flushing a one-dimensional flow column packed with complex contaminated soil sequentially with citric acid then a surfactant resulted in the removal of 85.6% of Zn, 62% of Pb, and 31.6% of HPO. The desorption distribution coefficients, K{sub Ubatch} and K{sub Lbatch}, converged to constant values as C{sub e} increased. An equilibrium model (ADR) and nonequilibrium models (TSNE and TRNE) were used to predict the desorption and transport of complex contaminants. The nonequilibrium models demonstrated better fits with the experimental values obtained from the column test than the equilibrium model. The ranges of K{sub Ubatch} and K{sub Lbatch} were very close to those of K{sub Ufit} and K{sub Lfit} determined from model simulations. The parameters (R, β, ω, α, and f) determined from model simulations were useful for characterizing the transport of contaminants within the soil matrix. The results of this study provide useful information for the operational parameters of the flushing process for soils with complex contamination.

  8. A transportable system for radioactivity contaminated water treatment

    International Nuclear Information System (INIS)

    2013-01-01

    Contaminated water treatment system called SARRY for retrieval and recovery of water in operation at the site of Fukushima Daiichi Nuclear Power Plant since August 2011 has been modified by compacting the system size to develop a mobile system SARRY-Aqua that can process Cs-contaminated water (one ton/hour) to the level of 10 Bq/kg. Installing the system in a small container with dimensions conforming to the international standards facilitates transportation by truck and enables the contaminated water treatment occurring in a variety of locations. (S. Ohno)

  9. Sediment and contaminant transport in a marine environment

    International Nuclear Information System (INIS)

    Onishi, Y.; Thompson, F.L.

    1986-01-01

    The finite-element model FETRA is an unsteady, verically averaged two-dimensional model to simulate the transport of sediment and contaminants (radionuclides, heavy metals, pesticides, etc.) in coastal and estuarine water. The model, together with the hydrodynamic model CAFE-I, was applied to the Irish Sea to predict the migration and accumulation of sediment (both cohesive and noncohesive) and of a radionuclide (dissolved and sediment-sorbed) in a tide- and wind-driven system. The study demonstrated that FETRA is a useful tool for assessing sediment and toxic contaminant transport in a marine environment

  10. Modelling contaminant transport in saturated aquifers

    International Nuclear Information System (INIS)

    Lakshminarayana, V.; Nayak, T.R.

    1990-01-01

    With the increase in population and industrialization the problem of pollution of groundwater has become critical. The present study deals with modelling of pollutant transport through saturated aquifers. Using this model it is possible to predict the concentration distribution, spatial as well as temporal, in the aquifer. The paper also deals with one of the methods of controlling the pollutant movement, namely by pumping wells. A simulation model is developed to determine the number, location and rate of pumping of a number of wells near the source of pollution so that the concentration is within acceptable limits at the point of interest. (Author) (18 refs., 14 figs., tab.)

  11. Transport of contaminated groundwater to a river

    International Nuclear Information System (INIS)

    Zeevaert, T.

    1990-09-01

    Scenario B7 deals with the discharges of Cs-137, Sr-90, Pu-239 and Np-237 with the groundwater from an aquifer into a river, through the river sediment. The contamination of agricultural soil, brought about through the dredging of top sediment from the river, was also considered. Four models participated in this exercise, providing best estimate values. Only one model supplied uncertainty estimates. Brief descriptions of the models and their aims are given. the modelling of the processes taken into account for the computation of the radionuclide concentrations in river and soil compartments are described and the input parameter values are given. The model results are discussed and the reasons for the differences between the models are explained. Important discrepancies were observed. As far as the steady-state concentrations are concerned they were due to differences in the parameter values and transfer processes considered. The time-dependent concentration values depended strongly on the approach adopted for the modelling of the migration of the nuclides through the deep sediment in the source region. The major source of uncertainty pointed out by the model which performed an uncertainty analysis, was the distribution coefficient in the deep sediment. The conclusions and recommendations for improvement of the models, given at the end of the report, accentuate the lack of understanding of the phenomena occurring at the geosphere-biosphere interface and the importance of good communications between scientists of different disciplines. (au)

  12. Simulation of contaminated sediment transport in White Oak Creek basin

    International Nuclear Information System (INIS)

    Bao, Y.; Clapp, R.B.; Brenkert, A.L.; Moore, T.D.; Fontaine, T.A.

    1995-01-01

    This paper presents a systematic approach to management of the contaminated sediments in the White Oak Creek watershed at Oak Ridge National Laboratory near Oak Ridge, Tennessee. The primary contaminant of concern is radioactive cesium-137 ( 137 Cs), which binds to soil and sediment particles. The key components in the approach include an intensive sampling and monitoring system for flood events; modeling of hydrological processes, sediment transport, and contaminant flux movement; and a decision framework with a detailed human health risk analysis. Emphasis is placed on modeling of watershed rainfall-runoff and contaminated sediment transport during flooding periods using the Hydrologic Simulation Program- Fortran (HSPF) model. Because a large number of parameters are required in HSPF modeling, the major effort in the modeling process is the calibration of model parameters to make simulation results and measured values agree as closely as possible. An optimization model incorporating the concepts of an expert system was developed to improve calibration results and efficiency. Over a five-year simulation period, the simulated flows match the observed values well. Simulated total amount of sediment loads at various locations during storms match with the observed values within a factor of 1.5. Simulated annual releases of 137 Cs off-site locations match the data within a factor of 2 for the five-year period. The comprehensive modeling approach can provide a valuable tool for decision makers to quantitatively analyze sediment erosion, deposition, and transport; exposure risk related to radionuclides in contaminated sediment; and various management strategies

  13. Modeling uranium transport in acidic contaminated groundwater with base addition

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Fan [Institute of Tibetan Plateau Research, Chinese Academy of Sciences; Luo, Wensui [ORNL; Parker, Jack C. [University of Tennessee, Knoxville (UTK); Brooks, Scott C [ORNL; Watson, David B [ORNL; Jardine, Philip [University of Tennessee, Knoxville (UTK); Gu, Baohua [ORNL

    2011-01-01

    This study investigates reactive transport modeling in a column of uranium(VI)-contaminated sediments with base additions in the circulating influent. The groundwater and sediment exhibit oxic conditions with low pH, high concentrations of NO{sub 3}{sup -}, SO{sub 4}{sup 2-}, U and various metal cations. Preliminary batch experiments indicate that additions of strong base induce rapid immobilization of U for this material. In the column experiment that is the focus of the present study, effluent groundwater was titrated with NaOH solution in an inflow reservoir before reinjection to gradually increase the solution pH in the column. An equilibrium hydrolysis, precipitation and ion exchange reaction model developed through simulation of the preliminary batch titration experiments predicted faster reduction of aqueous Al than observed in the column experiment. The model was therefore modified to consider reaction kinetics for the precipitation and dissolution processes which are the major mechanism for Al immobilization. The combined kinetic and equilibrium reaction model adequately described variations in pH, aqueous concentrations of metal cations (Al, Ca, Mg, Sr, Mn, Ni, Co), sulfate and U(VI). The experimental and modeling results indicate that U(VI) can be effectively sequestered with controlled base addition due to sorption by slowly precipitated Al with pH-dependent surface charge. The model may prove useful to predict field-scale U(VI) sequestration and remediation effectiveness.

  14. Modeling uranium transport in acidic contaminated groundwater with base addition

    International Nuclear Information System (INIS)

    Zhang Fan; Luo Wensui; Parker, Jack C.; Brooks, Scott C.; Watson, David B.; Jardine, Philip M.; Gu Baohua

    2011-01-01

    This study investigates reactive transport modeling in a column of uranium(VI)-contaminated sediments with base additions in the circulating influent. The groundwater and sediment exhibit oxic conditions with low pH, high concentrations of NO 3 - , SO 4 2- , U and various metal cations. Preliminary batch experiments indicate that additions of strong base induce rapid immobilization of U for this material. In the column experiment that is the focus of the present study, effluent groundwater was titrated with NaOH solution in an inflow reservoir before reinjection to gradually increase the solution pH in the column. An equilibrium hydrolysis, precipitation and ion exchange reaction model developed through simulation of the preliminary batch titration experiments predicted faster reduction of aqueous Al than observed in the column experiment. The model was therefore modified to consider reaction kinetics for the precipitation and dissolution processes which are the major mechanism for Al immobilization. The combined kinetic and equilibrium reaction model adequately described variations in pH, aqueous concentrations of metal cations (Al, Ca, Mg, Sr, Mn, Ni, Co), sulfate and U(VI). The experimental and modeling results indicate that U(VI) can be effectively sequestered with controlled base addition due to sorption by slowly precipitated Al with pH-dependent surface charge. The model may prove useful to predict field-scale U(VI) sequestration and remediation effectiveness.

  15. Modeling uranium transport in acidic contaminated groundwater with base addition

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Fan, E-mail: zhangfan@itpcas.ac.cn [Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, P.O. Box 2871, Beijing, 100085 (China); Luo Wensui [Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021 (China); Parker, Jack C. [Institute for a Secure and Sustainable Environment, Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Brooks, Scott C.; Watson, David B. [Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Jardine, Philip M. [Biosystems Engineering and Soil Science Department, University of Tennessee, Knoxville, TN 37996 (United States); Gu Baohua [Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2011-06-15

    This study investigates reactive transport modeling in a column of uranium(VI)-contaminated sediments with base additions in the circulating influent. The groundwater and sediment exhibit oxic conditions with low pH, high concentrations of NO{sub 3}{sup -}, SO{sub 4}{sup 2-}, U and various metal cations. Preliminary batch experiments indicate that additions of strong base induce rapid immobilization of U for this material. In the column experiment that is the focus of the present study, effluent groundwater was titrated with NaOH solution in an inflow reservoir before reinjection to gradually increase the solution pH in the column. An equilibrium hydrolysis, precipitation and ion exchange reaction model developed through simulation of the preliminary batch titration experiments predicted faster reduction of aqueous Al than observed in the column experiment. The model was therefore modified to consider reaction kinetics for the precipitation and dissolution processes which are the major mechanism for Al immobilization. The combined kinetic and equilibrium reaction model adequately described variations in pH, aqueous concentrations of metal cations (Al, Ca, Mg, Sr, Mn, Ni, Co), sulfate and U(VI). The experimental and modeling results indicate that U(VI) can be effectively sequestered with controlled base addition due to sorption by slowly precipitated Al with pH-dependent surface charge. The model may prove useful to predict field-scale U(VI) sequestration and remediation effectiveness.

  16. Software for modelling groundwater transport and contaminant migration

    International Nuclear Information System (INIS)

    Gishkelyuk, I.A.

    2008-01-01

    Facilities of modern software for modeling of groundwater transport and process of contaminant distribution are considered. Advantages of their application are discussed. The comparative analysis of mathematical modeling software of 'Groundwater modeling system' and 'Earth Science Module' from 'COMSOL Multiphysics' is carried out. (authors)

  17. Mechanisms of hydrologic transport of soil contaminants in Mortandad Canyon

    International Nuclear Information System (INIS)

    Hakonson, T.E.; White, G.C.

    1981-01-01

    The initial focus of this research will be on the selective sorting and transport of soil particles as they relate to altering the distribution of contaminants in soils and sediments. Several field experiments employing radionuclide-labeled soil particle size fractions are planned to accomplish research objectives

  18. OSPW contamination transport through peat soils : laboratory and greenhouse study

    Energy Technology Data Exchange (ETDEWEB)

    Rezanezhad, F.; Price, J.S. [Waterloo Univ., ON (Canada). Dept. of Geography; Rochefort, L.; Pouliot, R. [Laval Univ., Quebec City, PQ (Canada). Dept. of Phytology; Andersen, R. [Laval Univ., Quebec City, PQ (Canada). Dept. of Phytology; Macaulay Land Use Research Inst., Aberdeen (United Kingdom); Daly, C. [Suncor Energy, Fort McMurray, AB (Canada)

    2010-07-01

    Large portions of northern Canada are covered by peatlands, and the majority of post-mined landscapes have increased salinity, heavy metals and naphthenic acids (NA). This PowerPoint presentation discussed laboratory and greenhouse studies conducted to determine oil sands process water (OSPW) contamination transport through peat soils. Peat is a highly complex porous media. The presence of sodium and NA has a toxic effect on aquatic life. Greenhouse studies were conducted to determine the changes caused by OSPW in the microbial community of a peat matrix over 2 growing seasons. The study showed that peat has an exceptional ability to absorb the contaminants in OSPW water. NA and sodium transport through peat was significantly delayed by sorption, and by diffusion into immobile water contained in the peat matrix. The vegetation in the study was healthy and tolerant to the contaminants in the OSPW. tabs., figs.

  19. Color image analysis of contaminants and bacteria transport in porous media

    Science.gov (United States)

    Rashidi, Mehdi; Dehmeshki, Jamshid; Daemi, Mohammad F.; Cole, Larry; Dickenson, Eric

    1997-10-01

    Transport of contaminants and bacteria in aqueous heterogeneous saturated porous systems have been studied experimentally using a novel fluorescent microscopic imaging technique. The approach involves color visualization and quantification of bacterium and contaminant distributions within a transparent porous column. By introducing stained bacteria and an organic dye as a contaminant into the column and illuminating the porous regions with a planar sheet of laser beam, contaminant and bacterial transport processes through the porous medium can be observed and measured microscopically. A computer controlled color CCD camera is used to record the fluorescent images as a function of time. These images are recorded by a frame accurate high resolution VCR and are then analyzed using a color image analysis code written in our laboratories. The color images are digitized this way and simultaneous concentration and velocity distributions of both contaminant and bacterium are evaluated as a function of time and pore characteristics. The approach provides a unique dynamic probe to observe these transport processes microscopically. These results are extremely valuable in in-situ bioremediation problems since microscopic particle-contaminant- bacterium interactions are the key to understanding and optimization of these processes.

  20. 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)

  1. 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.)

  2. Efficient Bayesian experimental design for contaminant source identification

    Science.gov (United States)

    Zhang, Jiangjiang; Zeng, Lingzao; Chen, Cheng; Chen, Dingjiang; Wu, Laosheng

    2015-01-01

    In this study, an efficient full Bayesian approach is developed for the optimal sampling well location design and source parameters identification of groundwater contaminants. An information measure, i.e., the relative entropy, is employed to quantify the information gain from concentration measurements in identifying unknown parameters. In this approach, the sampling locations that give the maximum expected relative entropy are selected as the optimal design. After the sampling locations are determined, a Bayesian approach based on Markov Chain Monte Carlo (MCMC) is used to estimate unknown parameters. In both the design and estimation, the contaminant transport equation is required to be solved many times to evaluate the likelihood. To reduce the computational burden, an interpolation method based on the adaptive sparse grid is utilized to construct a surrogate for the contaminant transport equation. The approximated likelihood can be evaluated directly from the surrogate, which greatly accelerates the design and estimation process. The accuracy and efficiency of our approach are demonstrated through numerical case studies. It is shown that the methods can be used to assist in both single sampling location and monitoring network design for contaminant source identifications in groundwater.

  3. Monitoring Potential Transport of Radioactive Contaminants in Shallow Ephemeral Channels

    International Nuclear Information System (INIS)

    Miller Julianne J.; Mizell Steve A.; Nikolich George; Campbell Scott A.

    2012-01-01

    The U.S. Department of Energy (DOE) National Nuclear Security Administration (NNSA), Nevada Site Office (NSO), Environmental Restoration Soils Activity has authorized the Desert Research Institute (DRI) to conduct field assessments of potential sediment transport of contaminated soil from Corrective Action Unit (CAU) 550, Area 8 Smoky Contamination Area (CA), during precipitation runoff events. CAU 550 includes Corrective Action Sites (CASs) 08-23-03, 08-23-04, 08-23-06, and 08-23-07; these CASs are associated with tests designated Ceres, Smoky, Oberon, and Titania, respectively.

  4. Contaminant geochemistry. Interactions and transport in the subsurface environment

    Energy Technology Data Exchange (ETDEWEB)

    Berkowitz, Brian; Dror, Ishai; Yaron, Bruno [Weizmann Institute of Science, Rehovot (Israel). Dept. of Environmental Sciences and Energy Research

    2008-07-01

    This book combines earth science, subsurface hydrology and environmental geochemistry, providing a comprehensive background for specialists interested in the protection and sustainable management of the subsurface environment. The reader is introduced to the chemistry of contaminants, which usually disturb the natural equilibrium in the subsurface as a result of human activity. The major focus of the book is on contaminant reactions in soil solutions, groundwater and porous media solid phases, accounting for their persistence and transformation in the subsurface, as they are transported from the land surface into groundwater. Discussions on selected case studies are provided. (orig.)

  5. Sensitivity analyses of a colloid-facilitated contaminant transport model for unsaturated heterogeneous soil conditions.

    Science.gov (United States)

    Périard, Yann; José Gumiere, Silvio; Rousseau, Alain N.; Caron, Jean

    2013-04-01

    effects and the one-at-a-time approach (O.A.T); and (ii), we applied Sobol's global sensitivity analysis method which is based on variance decompositions. Results illustrate that ψm (maximum sorption rate of mobile colloids), kdmc (solute desorption rate from mobile colloids), and Ks (saturated hydraulic conductivity) are the most sensitive parameters with respect to the contaminant travel time. The analyses indicate that this new module is able to simulate the colloid-facilitated contaminant transport. However, validations under laboratory conditions are needed to confirm the occurrence of the colloid transport phenomenon and to understand model prediction under non-saturated soil conditions. Future work will involve monitoring of the colloidal transport phenomenon through soil column experiments. The anticipated outcome will provide valuable information on the understanding of the dominant mechanisms responsible for colloidal transports, colloid-facilitated contaminant transport and, also, the colloid detachment/deposition processes impacts on soil hydraulic properties. References: Šimůnek, J., C. He, L. Pang, & S. A. Bradford, Colloid-Facilitated Solute Transport in Variably Saturated Porous Media: Numerical Model and Experimental Verification, Vadose Zone Journal, 2006, 5, 1035-1047 Šimůnek, J., M. Šejna, & M. Th. van Genuchten, The C-Ride Module for HYDRUS (2D/3D) Simulating Two-Dimensional Colloid-Facilitated Solute Transport in Variably-Saturated Porous Media, Version 1.0, PC Progress, Prague, Czech Republic, 45 pp., 2012.

  6. 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.

  7. Analysis of contamination in liquids hydrocarbons transport for pipes

    Directory of Open Access Journals (Sweden)

    Eddy Ricardo Zárate Neira

    2003-01-01

    Full Text Available Pipeline contamination is usually understood to mean both the mixing effect produced when two different products transported by the same pipeline come into contact qith each other and often product of such mixing as well. This product os often referred to as "contamination" or as "interface" Cleary such intermixing is generally less serious in crude carrying, pipelines where each batch can become somewhat polluted by the batches inmediately preceding and immediately following without significant damage. However, the situation is different in a finished products pipeline, which may carry products as different as aircraft gasoline and light fuel oils. This article presents a brief description of the main factors influencing contamination with the objective of optimize conditions operating and to drive the more important respects about them.

  8. Contaminant plume configuration and movement: an experimental model

    Science.gov (United States)

    Alencoao, A.; Reis, A.; Pereira, M. G.; Liberato, M. L. R.; Caramelo, L.; Amraoui, M.; Amorim, V.

    2009-04-01

    The relevance of Science and Technology in our daily routines makes it compulsory to educate citizens who have both scientific literacy and scientific knowledge. These will allow them to be intervening citizens in a constantly changing society. Thus, physical and natural sciences are included in school curricula, both in primary and secondary education, with the fundamental aim of developing in the students the skills, attitudes and knowledge needed for the understanding of the planet Earth and its real problems. On the other hand, teaching in Geosciences is more and more based on practical methodologies which use didactic material, sustaining teachers' pedagogical practices and facilitating students' learning tasks suggested on the syllabus defined for each school level. Themes related to exploring the different components of the Hydrological Cycle and themes related to natural environment protection and preservation, namely water resources and soil contamination by industrial and urban sewage are examples of subject matters included on the Portuguese syllabus. These topics motivated the conception and construction of experimental models for the study of the propagation of pollutants on a porous medium. The experimental models allow inducing a horizontal flux of water though different kinds of permeable substances (e.g. sand, silt), with contamination spots on its surface. These experimental activities facilitate the student to understand the flow path of contaminating substances on the saturated zone and to observe the contaminant plume configuration and movement. The activities are explored in a teaching and learning process perspective where the student builds its own knowledge through real question- problem based learning which relate Science, Technology and Society. These activities have been developed in the framework of project ‘Water in the Environment' (CV/PVI/0854) of the POCTI Program (Programa Operacional "Ciência, Tecnologia, Inovação") financed

  9. Simplified model for radioactive contaminant transport: the TRANSS code

    International Nuclear Information System (INIS)

    Simmons, C.S.; Kincaid, C.T.; Reisenauer, A.E.

    1986-09-01

    A simplified ground-water transport model called TRANSS was devised to estimate the rate of migration of a decaying radionuclide that is subject to sorption governed by a linear isotherm. Transport is modeled as a contaminant mass transmitted along a collection of streamlines constituting a streamtube, which connects a source release zone with an environmental arrival zone. The probability-weighted contaminant arrival distribution along each streamline is represented by an analytical solution of the one-dimensional advection-dispersion equation with constant velocity and dispersion coefficient. The appropriate effective constant velocity for each streamline is based on the exact travel time required to traverse a streamline with a known length. An assumption used in the model to facilitate the mathematical simplification is that transverse dispersion within a streamtube is negligible. Release of contaminant from a source is described in terms of a fraction-remaining curve provided as input information. However, an option included in the code is the calculation of a fraction-remaining curve based on four specialized release models: (1) constant release rate, (2) solubility-controlled release, (3) adsorption-controlled release, and (4) diffusion-controlled release from beneath an infiltration barrier. To apply the code, a user supplies only a certain minimal number of parameters: a probability-weighted list of travel times for streamlines, a local-scale dispersion coefficient, a sorption distribution coefficient, total initial radionuclide inventory, radioactive half-life, a release model choice, and size dimensions of the source. The code is intended to provide scoping estimates of contaminant transport and does not predict the evolution of a concentration distribution in a ground-water flow field. Moreover, the required travel times along streamlines must be obtained from a prior ground-water flow simulation

  10. Contamination transfers during fuel transport cask loading. A concrete situation

    International Nuclear Information System (INIS)

    Fournel, B.; Turchet, J.P.; Faure, S.; Allinei, P.G.; Briquet, L.; Baubet, D.

    2002-01-01

    In 1998, a number of contamination cases detected during fuel shipments have been pointed out by the french nuclear safety authority. Wagon and casks external surfaces were partly contaminated upon arrival in Valognes railway terminal. Since then, measures taken by nuclear power plants operators in France and abroad solved the problem. In Germany, a report analyzing the situation in depth has been published in which correctives actions have been listed. In France, EDF launched a large cleanliness program (projet proprete radiologique) in order to better understand contamination transfers mechanisms during power plants exploitation and to list remediation actions to avoid further problems. In this context, CEA Department for Wastes Studies at Cadarache (CEA/DEN/DED) was in charge of a study about contamination transfers during fuel elements loading operations. It was decided to lead experiments for a concrete case. The loading of a transport cask at Tricastin-PWR-1 was followed in november 2000 and different analysis comprising water analysis and smear tests analysis were carried out and are detailed in this paper. Results are discussed and qualitatively compared to those obtained in Philippsburg-BWR, Germany for a similar set of tests. (authors)

  11. Experimental study on source efficiencies for estimating surface contamination level

    International Nuclear Information System (INIS)

    Ichiji, Takeshi; Ogino, Haruyuki

    2008-01-01

    Source efficiency was measured experimentally for various materials, such as metals, nonmetals, flooring materials, sheet materials and other materials, contaminated by alpha and beta emitter radioactive nuclides. Five nuclides, 147 Pm, 60 Co, 137 Cs, 204 Tl and 90 Sr- 90 Y, were used as the beta emitters, and one nuclide 241 Am was used as the alpha emitter. The test samples were prepared by placing drops of the radioactive standardized solutions uniformly on the various materials using an automatic quantitative dispenser system from Musashi Engineering, Inc. After placing drops of the radioactive standardized solutions, the test materials were allowed to dry for more than 12 hours in a draft chamber with a hood. The radioactivity of each test material was about 30 Bq. Beta rays or alpha rays from the test materials were measured with a 2-pi gas flow proportional counter from Aloka Co., Ltd. The source efficiencies of the metals, nonmetals and sheet materials were higher than 0.5 in the case of contamination by the 137 Cs, 204 Tl and 90 Sr- 90 Y radioactive standardized solutions, higher than 0.4 in the case of contamination by the 60 Co radioactive standardized solution, and higher than 0.25 in the case of contamination by the alpha emitter the 241 Am radioactive standardized solution. These values were higher than those given in Japanese Industrial Standards (JIS) documents. In contrast, the source efficiencies of some permeable materials were lower than those given in JIS documents, because source efficiency varies depending on whether the materials or radioactive sources are wet or dry. This study provides basic data on source efficiency, which is useful for estimating the surface contamination level of materials. (author)

  12. Experimental and modelling studies of radionuclide migration from contaminated groundwaters

    International Nuclear Information System (INIS)

    Tompkins, J. A.; Butler, A. P.; Wheater, H. S.; Shaw, G.; Wadey, P.; Bell, J. N. B.

    1994-01-01

    Lysimeter-based studies of radionuclide uptake by winter wheat are being undertaken to investigate soil-to-plant transfer processes. A five year multi-disciplinary research project has concentrated on the upward migration of contaminants from near surface water-tables and their subsequent uptake by a winter wheat crop. A weighted transfer factor approach and a physically based modelling methodology, for the simulation and prediction of radionuclide uptake, have been developed which offer alternatives to the traditional transfer factor approach. Integrated hydrological and solute transport models are used to simulate contaminant movement and subsequent root uptake. This approach enables prediction of radionuclide transport for a wide range of soil, plant and radionuclide types. This paper presents simulated results of 22 Na plant uptake and soil activity profiles, which are verified with respect to lysimeter data. The results demonstrate that a simple modelling approach can describe the variability in radioactivity in both the harvested crop and the soil profile, without recourse to a large number of empirical parameters. The proposed modelling technique should be readily applicable to a range of scales and conditions, since it embodies an understanding of the underlying physical processes of the system. This work constitutes part of an ongoing research programme being undertaken by UK Nirex Ltd., to assess the long term safety of a deep level repository for low and intermediate level nuclear waste. (author)

  13. One-dimensional contaminant transport model for the design of soil-bentonite slurry walls

    International Nuclear Information System (INIS)

    Khandelwal, A.; Rabideau, A.; Su, J.

    1997-01-01

    A user oriented computer model (TRANS1D) was developed for application to the analysis and design of vertical soil-bentonite barriers. TRANS1D is a collection of analytical and numerical solutions to the one dimensional advective-dispersive-reactive (ADR) equation. The primary objective in developing TRANS1D was to enable the designer of a barrier system to evaluate the potential system performance with respect to contaminant transport, without performing difficult and time consuming field or laboratory experiments. Several issues related to model application are discussed, including identification of governing transport processes, specification of boundary conditions, and parameter estimation. Model predictions are compared with the results of laboratory column experiments conducted with soil bentonite barrier material under diffusion-dominated conditions. Good agreement between model calibrations and experimental results was noted, with calibrated diffusion coefficients for organic contaminants consistent with literature values

  14. 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

  15. Contaminant transport at a waste residue deposit: 1. Inverse flow and non-reactive transport modelling

    DEFF Research Database (Denmark)

    Sonnenborg, Torben Obel; Engesgaard, Peter Knudegaard; Rosbjerg, Dan

    1996-01-01

    An application of an inverse flow and transport model to a contaminated aquifer is presented. The objective of the study is to identify physical and nonreactive flow and transport parameters through an optimization approach. The approach can be classified as a statistical procedure, where a flow...... to steady state versus transient flow conditions and to the amount of hydraulic and solute data used is investigated. The flow parameters, transmissivity and leakage factor, are estimated simultaneously with the transport parameters: source strength, porosity, and longitudinal dispersivity. This paper...

  16. A deterministic-probabilistic model for contaminant transport. User manual

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, F W; Crowe, A

    1980-08-01

    This manual describes a deterministic-probabilistic contaminant transport (DPCT) computer model designed to simulate mass transfer by ground-water movement in a vertical section of the earth's crust. The model can account for convection, dispersion, radioactive decay, and cation exchange for a single component. A velocity is calculated from the convective transport of the ground water for each reference particle in the modeled region; dispersion is accounted for in the particle motion by adding a readorn component to the deterministic motion. The model is sufficiently general to enable the user to specify virtually any type of water table or geologic configuration, and a variety of boundary conditions. A major emphasis in the model development has been placed on making the model simple to use, and information provided in the User Manual will permit changes to the computer code to be made relatively easily for those that might be required for specific applications. (author)

  17. Benchmarking of a Markov multizone model of contaminant transport.

    Science.gov (United States)

    Jones, Rachael M; Nicas, Mark

    2014-10-01

    A Markov chain model previously applied to the simulation of advection and diffusion process of gaseous contaminants is extended to three-dimensional transport of particulates in indoor environments. The model framework and assumptions are described. The performance of the Markov model is benchmarked against simple conventional models of contaminant transport. The Markov model is able to replicate elutriation predictions of particle deposition with distance from a point source, and the stirred settling of respirable particles. Comparisons with turbulent eddy diffusion models indicate that the Markov model exhibits numerical diffusion in the first seconds after release, but over time accurately predicts mean lateral dispersion. The Markov model exhibits some instability with grid length aspect when turbulence is incorporated by way of the turbulent diffusion coefficient, and advection is present. However, the magnitude of prediction error may be tolerable for some applications and can be avoided by incorporating turbulence by way of fluctuating velocity (e.g. turbulence intensity). © The Author 2014. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

  18. Modeling Groundwater-Surface Water Interaction and Contaminant Transport of Chlorinated Solvent Contaminated Site

    Science.gov (United States)

    Yimer Ebrahim, Girma; Jonoski, Andreja; van Griensven, Ann; Dujardin, Juliette; Baetelaan, Okke; Bronders, Jan

    2010-05-01

    Chlorinated-solvent form one of the largest groups of environmental chemicals. Their use and misuse in industry have lead to a large entry of these chemicals into the environment, resulting in widespread dissemination and oftentimes environmental contamination. Chlorinated solvent contamination of groundwater resources has been widely reported. For instance, there has been much interest in the assessment of these contaminant levels and their evolutions with time in the groundwater body below the Vilvoorde-Machelen industrial area (Belgium). The long industrial history of the area has lead to complex patterns of pollution from multiple sources and the site has been polluted to the extent that individual plumes are not definable any more. Understanding of groundwater/surface water interaction is a critical component for determining the fate of contaminant both in streams and ground water due to the fact that groundwater and surface water are in continuous dynamic interaction in the hydrologic cycle. The interaction has practical consequences in the quantity and quality of water in either system in the sense that depletion and/or contamination of one of the system will eventually affect the other one. The transition zone between a stream and its adjacent aquifer referred to as the hyporheic zone plays a critical role in governing contaminant exchange and transformation during water exchange between the two water bodies. The hyporheic zone of Zenne River ( the main receptor ) is further complicated due to the fact that the river banks are artificially trained with sheet piles along its reach extending some 12 m below the surface. This study demonstrates the use of MODFLOW, a widely used modular three-dimensional block-centred finite difference, saturated flow model for simulating the flow and direction of movement of groundwater through aquifer and stream-aquifer interaction and the use of transport model RT3D, a three-dimensional multi-species reactive transport model

  19. Release of Aged Contaminants from weathered sediments: Effects of sorbate speciation on scaling of reactive transport

    Energy Technology Data Exchange (ETDEWEB)

    Chorover, Jon [Univ. of Arizona, Tucson, AZ (United States); Perdrial, Nico [Univ. of Arizona, Tucson, AZ (United States); Mueller, Karl [Pennsylvania State Univ., University Park, PA (United States); Strepka, Caleb [Pennsylvania State Univ., University Park, PA (United States); O' Day, Peggy [Univ. of California, Merced, CA (United States); Rivera, Nelson [Univ. of California, Merced, CA (United States); Um, Wooyong [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chang, Hyun-Shik [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Steefel, Carl [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Thompson, Aaron [Univ. of Georgia, Athens, GA (United States)

    2012-08-14

    Hanford sediments impacted by hyperalkaline high level radioactive waste have undergone incongruent silicate mineral weathering concurrent with contaminant uptake (Chorover et al., 2008). In this project, we studied the impact of background pore water (BPW) on strontium, cesium and iodine desorption and transport in Hanford sediments that were experimentally weathered by contact with simulated hyperalkaline tank waste leachate (STWL) solutions. Using those lab-weathered Hanford sediments (HS) and model precipitates formed during nucleation from homogeneous STWL solutions (HN), we (i) provided thorough characterization of reaction products over a matrix of field-relevant gradients in contaminant concentration, PCO2, and reaction time; (ii) improved molecular-scale understanding of how sorbate speciation controls contaminant desorption from weathered sediments upon removal of caustic sources; and (iii) developed a mechanistic, predictive model of meso- to field-scale contaminant reactive transport under these conditions. Below, we provide some detailed descriptions of our results from this three year study, recently completed following a one-year no cost extension.

  20. Release of aged contaminants from weathered sediments: Effects of sorbate speciation on scaling of reactive transport

    Energy Technology Data Exchange (ETDEWEB)

    Chorover, Jon; Perdrial, Nico; Mueller, Karl; Strepka, Caleb; O’Day, Peggy; Rivera, Nelson; Um, Wooyong; Chang, Hyun-Shik; Steefel, Carl; Thompson, Aaron

    2012-11-05

    Hanford sediments impacted by hyperalkaline high level radioactive waste have undergone incongruent silicate mineral weathering concurrent with contaminant uptake. In this project, we studied the impact of background pore water (BPW) on strontium, cesium and iodine desorption and transport in Hanford sediments that were experimentally weathered by contact with simulated hyperalkaline tank waste leachate (STWL) solutions. Using those lab-weathered Hanford sediments (HS) and model precipitates formed during nucleation from homogeneous STWL solutions (HN), we (i) provided thorough characterization of reaction products over a matrix of field-relevant gradients in contaminant concentration, partial pressure of carbon dioxide, and reaction time; (ii) improved molecular-scale understanding of how sorbate speciation controls contaminant desorption from weathered sediments upon removal of caustic sources; and (iii) developed a mechanistic, predictive model of meso- to field-scale contaminant reactive transport under these conditions. In this final report, we provide detailed descriptions of our results from this three-year study, completed in 2012 following a one-year no cost extension.

  1. Low-rank Kalman filtering for efficient state estimation of subsurface advective contaminant transport models

    KAUST Repository

    El Gharamti, Mohamad; Hoteit, Ibrahim; Sun, Shuyu

    2012-01-01

    Accurate knowledge of the movement of contaminants in porous media is essential to track their trajectory and later extract them from the aquifer. A two-dimensional flow model is implemented and then applied on a linear contaminant transport model

  2. Final Project Report: Release of aged contaminants from weathered sediments: Effects of sorbate speciation on scaling of reactive transport

    Energy Technology Data Exchange (ETDEWEB)

    Jon Chorover, University of Arizona; Peggy O' €™Day, University of California, Merced; Karl Mueller, Penn State University; Wooyong Um, Pacific Northwest National Laboratory; Carl Steefel, Lawrence Berkeley National Laboratory

    2012-10-01

    Hanford sediments impacted by hyperalkaline high level radioactive waste have undergone incongruent silicate mineral weathering concurrent with contaminant uptake. In this project, we studied the impact of background pore water (BPW) on strontium, cesium and iodine desorption and transport in Hanford sediments that were experimentally weathered by contact with simulated hyperalkaline tank waste leachate (STWL) solutions. Using those lab-weathered Hanford sediments (HS) and model precipitates formed during nucleation from homogeneous STWL solutions (HN), we (i) provided detailed characterization of reaction products over a matrix of field-relevant gradients in contaminant concentration, PCO2, and reaction time; (ii) improved molecular-scale understanding of how sorbate speciation controls contaminant desorption from weathered sediments upon removal of caustic sources; and (iii) developed a mechanistic, predictive model of meso- to field-scale contaminant reactive transport under these conditions.

  3. Monitoring Potential Transport of Radioactive Contaminants in Shallow Ephemeral Channels: FY2015 and FY2016

    Energy Technology Data Exchange (ETDEWEB)

    Mizell, Steve A [Desert Research Inst. (DRI), Las Vegas, NV (United States); Miller, Julianne J [Desert Research Inst. (DRI), Las Vegas, NV (United States); McCurdy, Greg [Desert Research Inst. (DRI), Las Vegas, NV (United States); Campbell, Scott A [Desert Research Inst. (DRI), Las Vegas, NV (United States)

    2017-10-01

    The Desert Research Institute (DRI) is conducting a field assessment of the potential for contaminated soil to be transported from the Smoky Contamination Area (CA) as a result of storm runoff. This activity supports Nevada Nuclear Security Administration (NNSA) efforts to complete regulatory closure of the Soils Corrective Action Unit (CAU) contamination areas. The work is intended to confirm the likely mechanism of transport and determine the meteorological conditions that might cause movement of contaminated soils, as well as determine the particle size fraction that is most closely associated with transported radionuclide-contaminated soils. These data will facilitate the appropriate closure design and post-closure monitoring program.

  4. Monitoring Potential Transport of Radioactive Contaminants in Shallow Ephemeral Channels: FY2013 and FY2014 (revised)

    Energy Technology Data Exchange (ETDEWEB)

    Mizell, Steve A. [Desert Research Inst. (DRI), Las Vegas, NV (United States); Miller, Julianne J. [Desert Research Inst. (DRI), Las Vegas, NV (United States); McCurdy, Greg D. [Desert Research Inst. (DRI), Reno, NV (United States); Campbell, Scott A. [Desert Research Inst. (DRI), Las Vegas, NV (United States)

    2017-06-01

    The Desert Research Institute (DRI) is conducting a field assessment of the potential for contaminated soil to be transported from the Smoky Contamination Area (CA) as a result of storm runoff, which supports National Nuclear Security Administration (NNSA) efforts to complete regulatory closure of the Soils Corrective Action Unit (CAU) contamination areas. The work is intended to confirm the likely mechanism of transport and determine the meteorological conditions that might cause movement of contaminated soils, as well as determine the particle size fraction that is most closely associated with transported radionuclide-contaminated soils. These data will facilitate the appropriate closure design and post-closure monitoring program.

  5. Contaminant Attenuation and Transport Characterization of 200-DV-1 Operable Unit Sediment Samples

    Energy Technology Data Exchange (ETDEWEB)

    Truex, Michael J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Szecsody, James E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Qafoku, Nikolla [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Strickland, Christopher E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Moran, James J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lee, Brady D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Snyder, Michelle M.V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lawter, Amanda R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Resch, Charles T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Gartman, Brandy N. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zhong, Lirong [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Nims, Megan K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Saunders, Danielle L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Williams, Benjamin D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Horner, Jacob A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Leavy, Ian I. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Baum, Steven R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Christiansen, Beren B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Clayton, Ray E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McElroy, Erin M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Appriou, Delphine [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Tyrrell, Kimberly J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Striluk, Miranda L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2017-05-15

    A laboratory study was conducted to quantify contaminant attenuation processes and associated contaminant transport parameters that are needed to evaluate transport of contaminants through the vadose zone to the groundwater. The laboratory study information, in conjunction with transport analyses, can be used as input to evaluate the feasibility of Monitored Natural Attenuation and other remedies for the 200-DV-1 Operable Unit at the Hanford Site.

  6. Semianalytical solutions for contaminant transport under variable velocity field in a coastal aquifer

    Science.gov (United States)

    Koohbor, Behshad; Fahs, Marwan; Ataie-Ashtiani, Behzad; Simmons, Craig T.; Younes, Anis

    2018-05-01

    Existing closed-form solutions of contaminant transport problems are limited by the mathematically convenient assumption of uniform flow. These solutions cannot be used to investigate contaminant transport in coastal aquifers where seawater intrusion induces a variable velocity field. An adaptation of the Fourier-Galerkin method is introduced to obtain semi-analytical solutions for contaminant transport in a confined coastal aquifer in which the saltwater wedge is in equilibrium with a freshwater discharge flow. Two scenarios dealing with contaminant leakage from the aquifer top surface and contaminant migration from a source at the landward boundary are considered. Robust implementation of the Fourier-Galerkin method is developed to efficiently solve the coupled flow, salt and contaminant transport equations. Various illustrative examples are generated and the semi-analytical solutions are compared against an in-house numerical code. The Fourier series are used to evaluate relevant metrics characterizing contaminant transport such as the discharge flux to the sea, amount of contaminant persisting in the groundwater and solute flux from the source. These metrics represent quantitative data for numerical code validation and are relevant to understand the effect of seawater intrusion on contaminant transport. It is observed that, for the surface contamination scenario, seawater intrusion limits the spread of the contaminant but intensifies the contaminant discharge to the sea. For the landward contamination scenario, moderate seawater intrusion affects only the spatial distribution of the contaminant plume while extreme seawater intrusion can increase the contaminant discharge to the sea. The developed semi-analytical solution presents an efficient tool for the verification of numerical models. It provides a clear interpretation of the contaminant transport processes in coastal aquifers subject to seawater intrusion. For practical usage in further studies, the full

  7. Contaminant Attenuation and Transport Characterization of 200-UP-1 Operable Unit Sediment Samples

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Brady D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Szecsody, James E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Qafoku, Nikolla [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McElroy, Erin M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Baum, Steven R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Snyder, Michelle MV [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lawter, Amanda R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Resch, Charles T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Gartman, Brandy N. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zhong, Lirong [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Saunders, Danielle L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Williams, Benjamin D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Horner, Jacob A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Leavy, Ian I. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Christiansen, Beren B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Clayton, Ray E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Johnson, Kayla C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2017-09-27

    Contaminants disposed of at the land surface migrate through the vadose zone, forming plumes in groundwater. Processes that occur in the groundwater can attenuate contaminant concentrations during transport through the aquifer. For this reason, quantifying contaminant attenuation and contaminant transport processes in the aquifer, in support of the conceptual site model (CSM) and fate and transport modeling, are important for assessing the need for, and type of, remediation in the groundwater, including monitored natural attenuation (MNA). The framework to characterize attenuation and transport processes provided in U.S. Environmental Protection Agency (EPA) guidance documents was used to guide the laboratory effort reported herein.

  8. Neural Networks Simulation of the Transport of Contaminants in Groundwater

    Directory of Open Access Journals (Sweden)

    Enrico Zio

    2009-12-01

    Full Text Available The performance assessment of an engineered solution for the disposal of radioactive wastes is based on mathematical models of the disposal system response to predefined accidental scenarios, within a probabilistic approach to account for the involved uncertainties. As the most significant potential pathway for the return of radionuclides to the biosphere is groundwater flow, intensive computational efforts are devoted to simulating the behaviour of the groundwater system surrounding the waste deposit, for different values of its hydrogeological parameters and for different evolution scenarios. In this paper, multilayered neural networks are trained to simulate the transport of contaminants in monodimensional and bidimensional aquifers. The results obtained in two case studies indicate that the approximation errors are within the uncertainties which characterize the input data.

  9. Coliform contamination of a coastal embayment: Sources and transport pathways

    Science.gov (United States)

    Weiskel, P.K.; Howes, B.L.; Heufelder, G.R.

    1996-01-01

    Fecal bacterial contamination of nearshore waters has direct economic impacts to coastal communities through the loss of shellfisheries and restrictions of recreational uses. We conducted seasonal measurements of fecal coliform (FC) sources and transport pathways contributing to FC contamination of Buttermilk Bay, a shallow embayment adjacent to Buzzards Bay, MA. Typical of most coastal embayments, there were no direct sewage discharges (i.e., outfalls), and fecal bacteria from human, domestic animal, and wildlife pools entered open waters primarily through direct deposition or after transport through surface waters or groundwaters. Direct fecal coliform inputs to bay waters occurred primarily in winter (December-March) from waterfowl, ~33 x 1012 FC yr-1 or ~67% of the total annual loading. Effects of waterfowl inputs on bay FC densities were mitigated by their seasonality, wide distribution across the bay surface, and the apparent limited dispersal from fecal pellets. On-site disposal of sewage by septic systems was the single largest FC source in the watershed-embayment system, 460 x 1012 FC yr-1, but due to attenuation during subsurface transport only a minute fraction, rain events with discharge concentrated in nearshore zones, wet-weather flows were found to have a disproportionately high impact on nearshore FC levels. Elution of FC from shoreline deposits of decaying vegetation (wrack) comprised an additional coliform source. Both laboratory and field experiments suggest significant elution of bacteria from wrack, ~3 x 1012 FC yr-1 on a bay-wide basis (6% of annual input), primarily by periodic tidal flooding and possibly by major rain events. Release of coliforms during resuspension of subtidal sediments was estimated to be a minor source in this system (<1.5 x 1012 FC yr-1 or < 3% of annual input), primarily associated with large storm events in the fall and winter. Based upon the relative source strengths and the spatial and temporal patterns of FC input

  10. Deterministic sensitivity analysis for the numerical simulation of contaminants transport

    International Nuclear Information System (INIS)

    Marchand, E.

    2007-12-01

    The questions of safety and uncertainty are central to feasibility studies for an underground nuclear waste storage site, in particular the evaluation of uncertainties about safety indicators which are due to uncertainties concerning properties of the subsoil or of the contaminants. The global approach through probabilistic Monte Carlo methods gives good results, but it requires a large number of simulations. The deterministic method investigated here is complementary. Based on the Singular Value Decomposition of the derivative of the model, it gives only local information, but it is much less demanding in computing time. The flow model follows Darcy's law and the transport of radionuclides around the storage site follows a linear convection-diffusion equation. Manual and automatic differentiation are compared for these models using direct and adjoint modes. A comparative study of both probabilistic and deterministic approaches for the sensitivity analysis of fluxes of contaminants through outlet channels with respect to variations of input parameters is carried out with realistic data provided by ANDRA. Generic tools for sensitivity analysis and code coupling are developed in the Caml language. The user of these generic platforms has only to provide the specific part of the application in any language of his choice. We also present a study about two-phase air/water partially saturated flows in hydrogeology concerning the limitations of the Richards approximation and of the global pressure formulation used in petroleum engineering. (author)

  11. Evaluation of Triple Containment Method for Air Transport of Contaminated Human

    National Research Council Canada - National Science Library

    Neville, J

    2003-01-01

    A triple containment system intended for transport of biologically contaminated human remains was tested for its ability to maintain integrity during exposure to altitude changes representative of air transport...

  12. Solid waste leach characteristics and contaminant-sediment interactions Volume 2: Contaminant transport under unsaturated moisture contents

    International Nuclear Information System (INIS)

    Lindenmeier, C.W.; Serne, R.J.; Conca, J.L.

    1995-09-01

    The objectives of this report and subsequent volumes include describing progress on (1) development and optimization of experimental methods to quantify the release of contaminants from solid wastes and their subsequent interactions with unsaturated sediments and (2) the creation of empirical data that become input parameters to performance assessment (PA) analyses for future Hanford Site disposal units and baseline risk assessments for inactive and existing solid waste disposal units. For this report, efforts focused on developing methodologies to evaluate contaminant transport in Trench 8 (W-5 Burial Ground) sediments under unsaturated (vadose zone) conditions. To accomplish this task, a series of flow-through column tests were run using standard saturated column systems, Wierenga unsaturated column systems (both commercial and modified), and the Unsaturated Flow Apparatus (UFA). The reactants investigated were 85 Sr, 236 U, and 238 U as reactive tracers, and tritium as a non-reactive tracer. Results indicate that for moderately unsaturated conditions (volumetric water contents >50 % of saturation), the Wierenga system performed reasonably well such that long water residence times (50-147 h) were achieved, and reasonably good steady-state flow conditions were maintained. The major drawbacks in using this system for reactive tracer work included (1) the inability to achieve reproducible and constant moisture content below 50% of saturation, (2) the four to six month time required to complete a single test, and (3) the propensity for mechanical failure resulting from laboratory power outages during the prolonged testing period

  13. Chemical Contaminants in the Wadden Sea: sources, transport, fate and effects

    NARCIS (Netherlands)

    Laane, R.W.P.M.; Vethaak, A.D.; Gandrass, J.; Vorkamp, K.; Köhler, A.; Larsen, M.M.; Strand, J.

    2013-01-01

    The Wadden Sea receives contaminants from various sources and via various transport routes. The contaminants described in this overview are various metals (Cd, Cu, Hg, Pb and Zn) and various organic contaminants (polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and lindane

  14. EVALUATION OF THE STATE-OF-THE-ART CONTAMINATED SEDIMENT TRANSPORT AND FATE MODELING SYSTEM

    Science.gov (United States)

    Modeling approaches for evaluating the transport and fate of sediment and associated contaminants are briefly reviewed. The main emphasis is on: 1) the application of EFDC (Environmental Fluid Dynamics Code), the state-of-the-art contaminated sediment transport and fate public do...

  15. 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

  16. Contaminant transport in aquifers: improving the determination of model parameters

    International Nuclear Information System (INIS)

    Sabino, C.V.S.; Moreira, R.M.; Lula, Z.L.; Chausson, Y.; Magalhaes, W.F.; Vianna, M.N.

    1998-01-01

    Parameters conditioning the migration behavior of cesium and mercury are measured with their tracers 137 Cs and 203 Hg in the laboratory, using both batch and column experiments. Batch tests were used to define the sorption isotherm characteristics. Also investigated were the influences of some test parameters, in particular those due to the volume of water to mass of soil ratio (V/m). A provisional relationship between V/m and the distribution coefficient, K d , has been advanced, and a procedure to estimate K d 's valid for environmental values of the ratio V/m has been suggested. Column tests provided the parameters for a transport model. A major problem to be dealt with in such tests is the collimation of the radioactivity probe. Besides mechanically optimizing the collimator, a deconvolution procedure has been suggested and tested, with statistical criteria, to filter off both noise and spurious tracer signals. Correction procedures for the integrating effect introduced by sampling at the exit of columns have also been developed. These techniques may be helpful in increasing the accuracy required in the measurement of parameters conditioning contaminant migration in soils, thus allowing more reliable predictions based on mathematical model applications. (author)

  17. Monte Carlo simulation of the turbulent transport of airborne contaminants

    International Nuclear Information System (INIS)

    Watson, C.W.; Barr, S.

    1975-09-01

    A generalized, three-dimensional Monte Carlo model and computer code (SPOOR) are described for simulating atmospheric transport and dispersal of small pollutant clouds. A cloud is represented by a large number of particles that we track by statistically sampling simulated wind and turbulence fields. These fields are based on generalized wind data for large-scale flow and turbulent energy spectra for the micro- and mesoscales. The large-scale field can be input from a climatological data base, or by means of real-time analyses, or from a separate, subjectively defined data base. We introduce the micro- and mesoscale wind fluctuations through a power spectral density, to include effects from a broad spectrum of turbulent-energy scales. The role of turbulence is simulated in both meander and dispersal. Complex flow fields and time-dependent diffusion rates are accounted for naturally, and shear effects are simulated automatically in the ensemble of particle trajectories. An important adjunct has been the development of computer-graphics displays. These include two- and three-dimensional (perspective) snapshots and color motion pictures of particle ensembles, plus running displays of differential and integral cloud characteristics. The model's versatility makes it a valuable atmospheric research tool that we can adapt easily into broader, multicomponent systems-analysis codes. Removal, transformation, dry or wet deposition, and resuspension of contaminant particles can be readily included

  18. experimental investigation of sand minimum transport velocity

    African Journals Online (AJOL)

    user

    The production of reservoir fluid through long tiebacks/pipelines has emerged as one of ... transport in multiphase flows, the investigation of the ... Nigerian Journal of Technology ... associated with water-gas-oil-solid flow in pipeline in ... The mixture was well agitated using a .... operational conditions the limit deposit velocity.

  19. A nonequilibrium model for reactive contaminant transport through fractured porous media: Model development and semianalytical solution

    Science.gov (United States)

    Joshi, Nitin; Ojha, C. S. P.; Sharma, P. K.

    2012-10-01

    In this study a conceptual model that accounts for the effects of nonequilibrium contaminant transport in a fractured porous media is developed. Present model accounts for both physical and sorption nonequilibrium. Analytical solution was developed using the Laplace transform technique, which was then numerically inverted to obtain solute concentration in the fracture matrix system. The semianalytical solution developed here can incorporate both semi-infinite and finite fracture matrix extent. In addition, the model can account for flexible boundary conditions and nonzero initial condition in the fracture matrix system. The present semianalytical solution was validated against the existing analytical solutions for the fracture matrix system. In order to differentiate between various sorption/transport mechanism different cases of sorption and mass transfer were analyzed by comparing the breakthrough curves and temporal moments. It was found that significant differences in the signature of sorption and mass transfer exists. Applicability of the developed model was evaluated by simulating the published experimental data of Calcium and Strontium transport in a single fracture. The present model simulated the experimental data reasonably well in comparison to the model based on equilibrium sorption assumption in fracture matrix system, and multi rate mass transfer model.

  20. Wind-induced contaminant transport in near-surface soils with application to radon entry into buildings

    Energy Technology Data Exchange (ETDEWEB)

    Riley, William Jowett [Univ. of California, Berkeley, CA (United States)

    1996-05-01

    Indoor air exposures to gaseous contaminants originating in soil can cause large human health risks. To predict and control these exposures, the mechanisms that affect vapor transport in near-surface soils need to be understood. In particular, radon exposure is a concern since average indoor radon concentrations lead to much higher risks than are generally accepted for exposure to other environmental contaminants. This dissertation examines an important component of the indoor radon problem: the impacts of wind on soil-gas and radon transport and entry into buildings. The research includes experimental and modeling studies of wind`s interactions with a building`s superstructure and the resulting soil-gas and radon flows in the surrounding soil. In addition to exploring the effects of steady winds, a novel modeling technique is developed to examine the impacts of fluctuating winds on soil-gas and radon transport.

  1. Wind-induced contaminant transport in near-surface soils with application to radon entry into buildings

    International Nuclear Information System (INIS)

    Riley, W.J.

    1996-05-01

    Indoor air exposures to gaseous contaminants originating in soil can cause large human health risks. To predict and control these exposures, the mechanisms that affect vapor transport in near-surface soils need to be understood. In particular, radon exposure is a concern since average indoor radon concentrations lead to much higher risks than are generally accepted for exposure to other environmental contaminants. This dissertation examines an important component of the indoor radon problem: the impacts of wind on soil-gas and radon transport and entry into buildings. The research includes experimental and modeling studies of wind's interactions with a building's superstructure and the resulting soil-gas and radon flows in the surrounding soil. In addition to exploring the effects of steady winds, a novel modeling technique is developed to examine the impacts of fluctuating winds on soil-gas and radon transport

  2. Low-rank Kalman filtering for efficient state estimation of subsurface advective contaminant transport models

    KAUST Repository

    El Gharamti, Mohamad

    2012-04-01

    Accurate knowledge of the movement of contaminants in porous media is essential to track their trajectory and later extract them from the aquifer. A two-dimensional flow model is implemented and then applied on a linear contaminant transport model in the same porous medium. Because of different sources of uncertainties, this coupled model might not be able to accurately track the contaminant state. Incorporating observations through the process of data assimilation can guide the model toward the true trajectory of the system. The Kalman filter (KF), or its nonlinear invariants, can be used to tackle this problem. To overcome the prohibitive computational cost of the KF, the singular evolutive Kalman filter (SEKF) and the singular fixed Kalman filter (SFKF) are used, which are variants of the KF operating with low-rank covariance matrices. Experimental results suggest that under perfect and imperfect model setups, the low-rank filters can provide estimates as accurate as the full KF but at much lower computational effort. Low-rank filters are demonstrated to significantly reduce the computational effort of the KF to almost 3%. © 2012 American Society of Civil Engineers.

  3. Transport and degradation of contaminants in the vadose zone

    NARCIS (Netherlands)

    Schotanus, D.

    2013-01-01

    Leaching of contaminants from the vadose zone to the groundwater depends on the soil properties and the infiltration rate. In this thesis, organic degradable contaminants were studied, such as de-icing chemicals (consisting of propylene glycol, PG) and pesticides. Heterogeneous soil properties

  4. Radioactive contamination level of vehicles resulted from transporting fine rare-earth minerals by rail

    International Nuclear Information System (INIS)

    Han Kaichun; Yu Boyong; Gao Shengwei

    1997-01-01

    This paper presents monitoring results of radioactive contamination level of steel open wagon surface resulted from transporting fine rare-earth minerals. Under promising transport conditions (the packaging consists of two layers of plastic bags and two layers of plastic net sacks, each package contains 50 kg of minerals, each vehicle carries 60 t), the surface radioactivity (total α and total β) of 16 vehicles on two lines from Baotou to Wujiachuan (924 km) and from Baotou to Sankeshu (2236 km) was measured before loading, after unloading and washing, using α and β surface contamination detector. The results showed that the radioactive contamination level of the vehicle surface after unloading appeared significantly different. The contamination level of vehicle bases was higher than that of both sides, long distance vehicles was higher than that of short distance vehicles. The radioactive contamination level of vehicles surface after washing was below the standard limits, these vehicles can be used for ordinary goods transport

  5. Chaotic-Dynamical Conceptual Model to Describe Fluid Flow and Contaminant Transport in a Fractured Vadose Zone

    International Nuclear Information System (INIS)

    Faybishenko, Boris; Doughty, Christine; Geller, Jil T.

    1999-01-01

    DOE faces the remediation of numerous contaminated sites, such as those at Hanford, INEEL, LLNL, and LBNL, where organic and/or radioactive wastes were intentionally or accidentally released to the vadose zone from surface spills, underground tanks, cribs, shallow ponds, and deep wells. Migration of these contaminants through the vadose zone has led to the contamination of (or threatens to contaminate) underlying groundwater. A key issue in choosing a corrective action plan to clean up contaminated sites is the determination of the location, total mass, mobility and travel time to receptors for contaminants moving in the vadose zone. These problems are difficult to solve in a technically defensible and accurate manner because contaminants travel downward intermittently, through narrow pathways, driven by variations in environmental conditions. These preferential flow pathways can be difficult to find and predict. The primary objective of this project is to determine if and when dynamical chaos theory can be used to investigate infiltration of fluid and contaminant transport in heterogeneous soils and fractured rocks. The objective of this project is being achieved through the following activities: Development of multi scale conceptual models and mathematical and numerical algorithms for flow and transport, which incorporate both (a) the spatial variability of heterogeneous porous and fractured media and (b) the temporal dynamics of flow and transport; Development of appropriate experimental field and laboratory techniques needed to detect diagnostic parameters for chaotic behavior of flow; Evaluation of chaotic behavior of flow in laboratory and field experiments using methods from non-linear dynamics; Evaluation of the impact these dynamics may have on contaminant transport through heterogeneous fractured rocks and soils and remediation efforts. This approach is based on the consideration of multi scale spatial heterogeneity and flow phenomena that are affected by

  6. Experimental increase in availability of a PAH complex organic contamination from an aged contaminated soil: Consequences on biodegradation

    International Nuclear Information System (INIS)

    Cébron, Aurélie; Faure, Pierre; Lorgeoux, Catherine; Ouvrard, Stéphanie; Leyval, Corinne

    2013-01-01

    Although high PAH content and detection of PAH-degraders, the PAH biodegradation is limited in aged-contaminated soils due to low PAH availability (i.e., 1%). Here, we tried to experimentally increase the soil PAH availability by keeping both soil properties and contamination composition. Organic extract was first removed and then re-incorporated in the raw soil as fresh contaminants. Though drastic, this procedure only allowed a 6-time increase in the PAH availability suggesting that the organic constituents more than ageing were responsible for low availability. In the re-contaminated soil, the mineralization rate was twice more important, the proportion of 5–6 cycles PAH was higher indicating a preferential degradation of lower molecular weight PAH. The extraction treatment induced bacterial and fungal community structures modifications, Pseudomonas and Fusarium solani species were favoured, and the relative quantity of fungi increased. In re-contaminated soil the percentage of PAH-dioxygenase gene increased, with 10 times more Gram negative representatives. -- Highlights: ► Re-incorporation of soil organic extract increased 6-times the PAH availability. ► Complexity of organic contamination is the main driver of PAH availability. ► Biodegradation of PAH with less than 5-cycles increased with increasing PAH availability. ► Pseudomonas and Fusarium species are favoured when PAH availability increased. -- More than ageing, the complexity of organic contamination is the main driver of PAH availability

  7. Microbial behaviour and cross contamination between cargoes in containerized transportation of food

    DEFF Research Database (Denmark)

    Abban, Stephen

    Transportation is central to the global food and feed supply chain. Thus issues of safety, especially cross contamination with pathogens during food transit should be important in food handling operations. A large proportion of the worlds’ food cargo is moved using intermodal cargo containers...... chain, its role in food safety cannot be ignored. Unfortunately not much effort has been put, scientifically, into understanding the role of the various features of the transportation links in food cross contamination (compared to studies for homes, processing factories and farm yards). The PhD project...... has attempted to shed light on containerized food transport and some of its important attributes as regards hygiene and cross contamination. The overall aim of the study was to ‘identify possible microbial hazards and ways of cross contamination during containerized transportation of foods...

  8. Performance testing of the sediment-contaminant transport model, SERATRA, at different rivers

    International Nuclear Information System (INIS)

    Onishi, Y.; Yabusaki, S.B.; Kincaid, C.T.

    1982-04-01

    Mathematical models of sediment-contaminant migration in surface water must account for transport, intermedia transfer, decay and degradation, and transformation processes. The unsteady, two dimensional, sediment-contaminant transport code, SERATRA (Onishi, Schreiber and Codell 1980) includes these mechanisms. To assess the accuracy of SERATRA to simulate the sediment-contaminant transport and fate processes, the code was tested against one-dimensional analytical solutions, checked for its mass balance, and applied to field sites. The field application cases ranged from relatively simple, steady conditions to unsteady, nonuniform conditions for large, intermediate, and small rivers. It was found that SERATRA is capable of simulating sediment-contaminant transport under a wide range of conditions

  9. Configuration Management Plan for Long Length Contaminated Equipment Receiver and Transport Trailers

    International Nuclear Information System (INIS)

    DALE, R.N.

    2000-01-01

    Long Length Contaminated Equipment Removal System Receiver Trailer and Transport Trailer require a configuration management plan for design, requirements and operations baseline documents. This report serves as the plan for the Trailers

  10. Effects of lag and maximum growth in contaminant transport and biodegradation modeling

    International Nuclear Information System (INIS)

    Wood, B.D.; Dawson, C.N.

    1992-06-01

    The effects of time lag and maximum microbial growth on biodegradation in contaminant transport are discussed. A mathematical model is formulated that accounts for these effects, and a numerical case study is presented that demonstrates how lag influences biodegradation

  11. How historical copper contamination affects soil structure and mobilization and transport of colloids

    DEFF Research Database (Denmark)

    Paradelo, Marcos; Møldrup, Per; Holmstrup, Martin

    between 0.01 to 0.43 pore volumes, with longer times for the most contaminated point, likely related with its higher soil density and lower air permeability. The copper pollution affected colloid and tracer transport in the soil columns. The release of colloids especially in the most contaminated points...

  12. Flow and contaminant transport in an airliner cabin induced by a moving body: Model experiments and CFD predictions

    Science.gov (United States)

    Poussou, Stephane B.; Mazumdar, Sagnik; Plesniak, Michael W.; Sojka, Paul E.; Chen, Qingyan

    2010-08-01

    The effects of a moving human body on flow and contaminant transport inside an aircraft cabin were investigated. Experiments were performed in a one-tenth scale, water-based model. The flow field and contaminant transport were measured using the Particle Image Velocimetry (PIV) and Planar Laser-Induced Fluorescence (PLIF) techniques, respectively. Measurements were obtained with (ventilation case) and without (baseline case) the cabin environmental control system (ECS). The PIV measurements show strong intermittency in the instantaneous near-wake flow. A symmetric downwash flow was observed along the vertical centerline of the moving body in the baseline case. The evolution of this flow pattern is profoundly perturbed by the flow from the ECS. Furthermore, a contaminant originating from the moving body is observed to convect to higher vertical locations in the presence of ventilation. These experimental data were used to validate a Computational Fluid Dynamic (CFD) model. The CFD model can effectively capture the characteristic flow features and contaminant transport observed in the small-scale model.

  13. Experimental studies on decontamination in first aid for contaminated wounds

    International Nuclear Information System (INIS)

    Kusama, Tomoko; Ogaki, Kazushi; Yoshizawa, Yasuo

    1982-01-01

    The present study was designed to investigate the decontamination procedures in first aid for wounds contaminated with radionuclides. Abrasion of mouse skin was contaminated with 58 CoCl 2 . Irrigation by decontamination fluids began at 2 min after administration of the radionuclide and continued for 14 min. Tap water, 0.5% Hyamine solution or 10% Ca-DTPA solution were used as the decontamination fluids. Radioactivities of whole body, wounded skin surface and washed solution were measured with an animal counter with 5 cm NaI(Tl) and a well-type auto-gamma-counter. Decontamination effectiveness were expressed as follows: (1) absorption rate of radionuclide through the wound and (2) residual rate of radionuclide on the wound. More than 20% of the radionuclide applied on the wounded skin was absorbed in 15 min after contamination. The absorption rate decreased to 2% by the decontamination procedures. The Ca-DTPA solution reduced the residual rate of radionuclide on the wounds. The results suggested that the decontamination for the contaminated wounds should begin as soon as possible. Irrigation with 0.5% Hyamine solution has been advocated for the decontamination in the first aid. (author)

  14. A model for the derivation of new transport limits for non-fixed contamination

    International Nuclear Information System (INIS)

    Thierfeldt, S.; Lorenz, B.; Hesse, J.

    2004-01-01

    The IAEA Regulations for the Safe Transport of Radioactive Material contain requirements for contamination limits on packages and conveyances used for the transport of radioactive material. Current contamination limits for packages and conveyances under routine transport conditions have been derived from a model proposed by Fairbairn more than 40 years ago. This model has proven effective if used with pragmatism, but is based on very conservative as well as extremely simple assumptions which is in no way appropriate any more and which is not compatible with ICRP recommendations regarding radiation protection standards. Therefore, a new model has now been developed which reflects all steps of the transport process. The derivation of this model has been fostered by the IAEA by initiating a Co-ordinated Research Project. The results of the calculations using this model could be directly applied as new nuclide specific transport limits for the non-fixed contamination

  15. A model for the derivation of new transport limits for non-fixed contamination

    Energy Technology Data Exchange (ETDEWEB)

    Thierfeldt, S. [Brenk Systemplanung GmbH, Aachen (Germany); Lorenz, B. [GNS Gesellschaft fuer Nuklearservice, Essen (Germany); Hesse, J. [RWE Power AG, Essen (Germany)

    2004-07-01

    The IAEA Regulations for the Safe Transport of Radioactive Material contain requirements for contamination limits on packages and conveyances used for the transport of radioactive material. Current contamination limits for packages and conveyances under routine transport conditions have been derived from a model proposed by Fairbairn more than 40 years ago. This model has proven effective if used with pragmatism, but is based on very conservative as well as extremely simple assumptions which is in no way appropriate any more and which is not compatible with ICRP recommendations regarding radiation protection standards. Therefore, a new model has now been developed which reflects all steps of the transport process. The derivation of this model has been fostered by the IAEA by initiating a Co-ordinated Research Project. The results of the calculations using this model could be directly applied as new nuclide specific transport limits for the non-fixed contamination.

  16. Preliminary Experimental Analysis of Soil Stabilizers for Contamination Control

    International Nuclear Information System (INIS)

    Lagos, L.; Varona, J.; Zidan, A.; Gudavalli, R.; Wu, Kuang-His

    2006-01-01

    A major focus of Department of Energy's (DOE's) environmental management mission at the Hanford site involves characterizing and remediating contaminated soil and groundwater; stabilizing contaminated soil; remediating disposal sites; decontaminating and decommissioning structures, and demolishing former plutonium production process buildings, nuclear reactors, and separation plants; maintaining inactive waste sites; transitioning facilities into the surveillance and maintenance program; and mitigating effects to biological and cultural resources from site development and environmental cleanup and restoration activities. For example, a total of 470,914 metric tons of contaminated soil from 100 Areas remediation activities were disposed at the Environmental Restoration Disposal Facility (ERDF) during 2004. The Applied Research Center (ARC) at Florida International University (FIU) is supporting the Hanford's site remediation program by analyzing the effectiveness of several soil stabilizers (fixatives) for contamination control during excavation activities. The study is focusing on determining the effects of varying soil conditions, temperature, humidity and wind velocity on the effectiveness of the candidate stabilizers. The test matrix consists of a soil penetration-depth study, wind tunnel experiments for determination of threshold velocity, and temperature and moisture-controlled drying/curing experiments. These three set of experiments are designed to verify performance metrics, as well as provide insight into what fundamental forces are altered by the use of the stabilizer. This paper only presents the preliminary results obtained during wind tunnel experiments using dry Hanford soil samples (with 2.7% moisture by weight). These dry soil samples were exposed to varying wind speeds from 2.22 m/sec to 8.88 m/sec. Furthermore, airborne particulate data was collected for the dry Hanford soil experiments using an aerosol analyzer instrument. (authors)

  17. Experimental Challenges to Stiffness as a Transport Paradigm

    Science.gov (United States)

    Luce, T. C.

    2017-10-01

    Transport in plasmas is treated experimentally as a relationship between gradients and fluxes in analogy to the random-walk problem. Gyrokinetic models often predict strong increases in local flux for small increases in local gradient when above a threshold, holding all other parameters fixed. This has been named `stiffness'. The radial scalelength is then expected to vary little with source strength as a result of high stiffness. To probe the role of ExB shearing on stiffness in the DIII-D tokamak, two neutral beam injection power scans in H-mode plasmas were specially crafted-one with constant, low torque and one with increasing torque. The ion heat, electron heat, and ion toroidal momentum transport do not show expected signatures of stiffness, while the ion particle transport does. The ion heat transport shows the clearest discrepancy; the normalized heat flux drops with increasing inverse ion temperature scalelength. ExB shearing affects the transport magnitude, but not the scalelength dependence. Linear gyrofluid (TGLF) and nonlinear gyrokinetic (GYRO) predictions show stiff ion heat transport around the experimental profiles. The ion temperature gradient required to match the ion heat flux with increasing auxiliary power is not correctly described by TGLF, even when parameters are varied within the experimental uncertainties. TGLF also underpredicts transport at smaller radii, but overpredicts transport at larger radii. Independent of the theory/experiment comparison, it is not clear that the theoretical definition of stiffness yields any prediction about parameter scans such as the power scans here, because the quantities that must be held fixed to quantify stiffness are varied. A survey of recent literature indicated that profile resilience is routinely attributed to stiffness, but simple model calculations show profile resilience does not imply stiffness. Taken together, these observations challenge the use of local stiffness as a paradigm for explaining

  18. Feed gas contaminant removal in ion transport membrane systems

    Science.gov (United States)

    Carolan, Michael Francis [Allentown, PA; Miller, Christopher Francis [Macungie, PA

    2008-09-16

    Method for gas purification comprising (a) obtaining a feed gas stream containing one or more contaminants selected from the group consisting of volatile metal oxy-hydroxides, volatile metal oxides, and volatile silicon hydroxide; (b) contacting the feed gas stream with a reactive solid material in a guard bed and reacting at least a portion of the contaminants with the reactive solid material to form a solid reaction product in the guard bed; and (c) withdrawing from the guard bed a purified gas stream.

  19. Innovative alpha radioactivity monitor for clearance level inspection based on ionized air transport technology (2). CFD-simulated and experimental ion transport efficiencies for uranium-attached pipes

    International Nuclear Information System (INIS)

    Hirata, Yosuke; Nakahara, Katsuhiko; Sano, Akira; Sato, Mitsuyoshi; Aoyama, Yoshio; Miyamoto, Yasuaki; Yamaguchi, Hiromi; Nanbu, Kenichi; Takahashi, Hiroyuki; Oda, Akinori

    2007-01-01

    An innovative alpha radioactivity monitor for clearance level inspection has been developed. This apparatus measures an ion current resulting from air ionization by alpha particles. Ions generated in the measurement chamber of about 1 m 3 in volume are transported by airflow to a sensor and measured. This paper presents computational estimation of ion transport efficiencies for two pipes with different lengths, the inner surfaces of which were covered with a thin layer of uranium. These ion transport efficiencies were compared with those experimentally obtained for the purpose of our model validation. Good agreement was observed between transport efficiencies from simulations and those experimentally estimated. Dependence of the transport efficiencies on the region of uranium coating was also examined, based on which anticipated errors arising from unclear positions of contamination are also discussed. (author)

  20. Subsurface contaminant transport from the liquid disposal area, CRNL

    International Nuclear Information System (INIS)

    Killey, R.W.D.; Munch, J.H.

    1984-01-01

    This report summarizes geologic, hydrogeologic and geochemical information obtained from a detailed study of the aquifer receiving contaminated waste-waters from the Chemical Pit. Geologically, the study area features wind-deposited sand overlying a continuous lacustrine clayey silt and a bouldery basal till. Medium to coarse sands locally found at the base of the sand sequence appear to represent stream channel deposits following a buried drainage course towards Perch Lake. These channel sands significantly influence groundwater flow; 3-dimensional models will be required to mathematically simulate the system. Based on the subsurface data, calculated groundwater residence times between the infiltration pit and points of discharge to surface into the East Swamp range from 4 to 22 months. The shortest observed residence time for a non-reactive radio-nuclide is 5 months. Tritium data confirm that contamination is confined to the sands, but show that within the sand aquifer there is considerable heterogeneity in the distribution and rates of groundwater flow. Samples of contaminated groundwaters collected during this study featured increased redox potentials, increased acidity, and minor increases in some major ions relative to local uncontaminated groundwater. Extensive oxidation of the sands in contaminated portions of the aquifer may reflect much greater chemical differences in plume groundwaters in the past

  1. Experimental study on mass transfer of contaminants through an enthalpy recovery unit with polymer membrane foils

    DEFF Research Database (Denmark)

    Nie, Jinzhe; Fang, Lei

    2014-01-01

    Laboratory experimental studies were conducted to investigate the mass transfer of contaminants through a total heat recovery unit with polymer membranes foils. The studies were conducted in twin climate chambers which simulated outdoor and indoor thermal climates. One manufacturd total heat...... chemical gases were used to simulate air contaminants. The concentrations of dosed contaminants in the supply and exhaust air upstream and downstream of the total heat recovery unit were measured with Multi-Gas Monitor Innova 1316 in real time. Experiment results showed that 5% to 9% of dosed contaminants...... could transfer from exhaust air to supply air through the enthalpy recovery unit. The mass transfer efficiency of contaminants was independent of the hygro-thermal differences between indoor and outdoor climate conditions. The mass transfer ratio of the chemical contaminants in the total heat recovery...

  2. Methane Bubbles Transport Particles From Contaminated Sediment to a Lake Surface

    Science.gov (United States)

    Delwiche, K.; Hemond, H.

    2017-12-01

    Methane bubbling from aquatic sediments has long been known to transport carbon to the atmosphere, but new evidence presented here suggests that methane bubbles also transport particulate matter to a lake surface. This transport pathway is of particular importance in lakes with contaminated sediments, as bubble transport could increase human exposure to toxic metals. The Upper Mystic Lake in Arlington, MA has a documented history of methane bubbling and sediment contamination by arsenic and other heavy metals, and we have conducted laboratory and field studies demonstrating that methane bubbles are capable of transporting sediment particles over depths as great as 15 m in Upper Mystic Lake. Methane bubble traps were used in-situ to capture particles adhered to bubble interfaces, and to relate particle mass transport to bubble flux. Laboratory studies were conducted in a custom-made 15 m tall water column to quantify the relationship between water column height and the mass of particulate transport. We then couple this particle transport data with historical estimates of ebullition from Upper Mystic Lake to quantify the significance of bubble-mediated particle transport to heavy metal cycling within the lake. Results suggest that methane bubbles can represent a significant pathway for contaminated sediment to reach surface waters even in relatively deep water bodies. Given the frequent co-occurrence of contaminated sediments and high bubble flux rates, and the potential for human exposure to heavy metals, it will be critical to study the significance of this transport pathway for a range of sediment and contaminant types.

  3. Study on Contaminant Transportation of a Typical Chemical Industry Park Based on GMS Software

    Science.gov (United States)

    Huang, LinXian; Liu, GuoZhen; Xing, LiTing; Liu, BenHua; Xu, ZhengHe; Yang, LiZhi; Zhu, HebgHua

    2018-03-01

    The groundwater solute transport model can effectively simulated the transport path, the transport scope, and the concentration of contaminant which can provide quantitative data for groundwater pollution repair and groundwater resource management. In this study, we selected biological modern technology research base of Shandong province as research objective and simulated the pollution characteristic of typicalcontaminant cis-1, 3-dichloropropene under different operating conditions by using GMS software.

  4. Experimental study of the longitudinal instability for beam transport

    International Nuclear Information System (INIS)

    Reiser, M.; Wang, J.G.; Guo, W.M.; Wang, D.X.

    1990-01-01

    Theoretical model for beam longitudinal instability in a transport pipe with general wall impedance is considered. The result shows that a capacitive wall tends to stabilize the beam. The experimental study of the instability for a pure resistive-wall is presented, including the design parameters, setup and components for the experiment. 6 refs., 3 figs

  5. Spent Fuel Transportation Package Performance Study - Experimental Design Challenges

    International Nuclear Information System (INIS)

    Snyder, A. M.; Murphy, A. J.; Sprung, J. L.; Ammerman, D. J.; Lopez, C.

    2003-01-01

    Numerous studies of spent nuclear fuel transportation accident risks have been performed since the late seventies that considered shipping container design and performance. Based in part on these studies, NRC has concluded that the level of protection provided by spent nuclear fuel transportation package designs under accident conditions is adequate. [1] Furthermore, actual spent nuclear fuel transport experience showcase a safety record that is exceptional and unparalleled when compared to other hazardous materials transportation shipments. There has never been a known or suspected release of the radioactive contents from an NRC-certified spent nuclear fuel cask as a result of a transportation accident. In 1999 the United States Nuclear Regulatory Commission (NRC) initiated a study, the Package Performance Study, to demonstrate the performance of spent fuel and spent fuel packages during severe transportation accidents. NRC is not studying or testing its current regulations, a s the rigorous regulatory accident conditions specified in 10 CFR Part 71 are adequate to ensure safe packaging and use. As part of this study, NRC currently plans on using detailed modeling followed by experimental testing to increase public confidence in the safety of spent nuclear fuel shipments. One of the aspects of this confirmatory research study is the commitment to solicit and consider public comment during the scoping phase and experimental design planning phase of this research

  6. Experimental transport phenomena and optimization strategies for thermoelectrics

    Energy Technology Data Exchange (ETDEWEB)

    Ehrlich, A C; Gillespie, D J

    1997-07-01

    When a new and promising thermoelectric material is discovered, an effort is undertaken to improve its figure of merit. If the effort is to be more efficient than one of trial and error with perhaps some rule of thumb guidance then it is important to be able to make the connection between experimental data and the underlying material characteristics, electronic and phononic, that influence the figure of merit. Transport and fermiology experimental data can be used to evaluate these material characteristics and thus establish trends as a function of some controllable parameter, such as composition. In this paper some of the generic-materials characteristics, generally believed to be required for a high figure of merit, will be discussed in terms of the experimental approach to their evaluation and optimization. Transport and fermiology experiments will be emphasized and both will be outlined in what they can reveal and what can be obscured by the simplifying assumptions generally used in their interpretation.

  7. Experimental and Numerical Investigations on Colloid-facilitated Plutonium Reactive Transport in Fractured Tuffaceous Rocks

    Science.gov (United States)

    Dai, Z.; Wolfsberg, A. V.; Zhu, L.; Reimus, P. W.

    2017-12-01

    Colloids have the potential to enhance mobility of strongly sorbing radionuclide contaminants in fractured rocks at underground nuclear test sites. This study presents an experimental and numerical investigation of colloid-facilitated plutonium reactive transport in fractured porous media for identifying plutonium sorption/filtration processes. The transport parameters for dispersion, diffusion, sorption, and filtration are estimated with inverse modeling for minimizing the least squares objective function of multicomponent concentration data from multiple transport experiments with the Shuffled Complex Evolution Metropolis (SCEM). Capitalizing on an unplanned experimental artifact that led to colloid formation and migration, we adopt a stepwise strategy to first interpret the data from each experiment separately and then to incorporate multiple experiments simultaneously to identify a suite of plutonium-colloid transport processes. Nonequilibrium or kinetic attachment and detachment of plutonium-colloid in fractures was clearly demonstrated and captured in the inverted modeling parameters along with estimates of the source plutonium fraction that formed plutonium-colloids. The results from this study provide valuable insights for understanding the transport mechanisms and environmental impacts of plutonium in fractured formations and groundwater aquifers.

  8. Influence of particle sorting in transport of sediment-associated contaminants

    International Nuclear Information System (INIS)

    Lane, L.J.; Hakonson, T.E.

    1982-01-01

    Hydrologic and sediment transport models are developed to route the flow of water and sediment (by particle size classes) in alluvial stream channels. A simplified infiltration model is used to compute runoff from upland areas and flow is routed in ephemeral stream channels to account for infiltration or transmission losses in the channel alluvium. Hydraulic calculations, based on the normal flow assumption and an approximating hydrograph, are used to compute sediment transport by particle size classes. Contaminants associated with sediment particles are routed in the stream channels to predict contaminatant transport by particle size classes. An empirical adjustment factor, the enrichment ratio, is shown to be a function of the particle size distribution of stream bed sediments, contaminant concentrations by particle size, differential sediment transport rates, and the magnitude of the runoff event causing transport of sediment and contaminants. This analysis and an example application in a liquid effluent-receiving area illustrate the significance of particle sorting in transport of sediment associated contaminants

  9. Transport and repair of contaminated nuclear components - liabilities and insurance

    International Nuclear Information System (INIS)

    Brunego, C.; Deprimoz, J.; Engelhard, M.

    1983-01-01

    The nuclear park has been constructed fairly recently and has not yet required large-scale maintenance efforts; however account should now be taken of the fact that periodic checks of nuclear power plants will imply systematic transfers of irradiated or contaminated materials outside the plants. In this context, the paper reviews the nuclear third party liability regime under the Paris Convention and the Euratom directives on radiation protection. It then describes the cover offered by insurance pools in several European countries. (NEA) [fr

  10. Contaminant flow and transport simulation in cracked porous media using locally conservative schemes

    KAUST Repository

    Song, Pu

    2012-10-25

    The purpose of this paper is to analyze some features of contaminant flow passing through cracked porous medium, such as the influence of fracture network on the advection and diffusion of contaminant species, the impact of adsorption on the overall transport of contaminant wastes. In order to precisely describe the whole process, we firstly build the mathematical model to simulate this problem numerically. Taking into consideration of the characteristics of contaminant flow, we employ two partial differential equations to formulate the whole problem. One is flow equation; the other is reactive transport equation. The first equation is used to describe the total flow of contaminant wastes, which is based on Darcy law. The second one will characterize the adsorption, diffusion and convection behavior of contaminant species, which describes most features of contaminant flow we are interested in. After the construction of numerical model, we apply locally conservative and compatible algorithms to solve this mathematical model. Specifically, we apply Mixed Finite Element (MFE) method to the flow equation and Discontinuous Galerkin (DG) method for the transport equation. MFE has a good convergence rate and numerical accuracy for Darcy velocity. DG is more flexible and can be used to deal with irregular meshes, as well as little numerical diffusion. With these two numerical means, we investigate the sensitivity analysis of different features of contaminant flow in our model, such as diffusion, permeability and fracture density. In particular, we study K d values which represent the distribution of contaminant wastes between the solid and liquid phases. We also make omparisons of two different schemes and discuss the advantages of both methods. © 2012 Global Science Press.

  11. Analysis of heat transfer and contaminant transport in fume hoods

    International Nuclear Information System (INIS)

    Pathanjali, C.; Rahman, M.M.

    1996-01-01

    The paper presents the analysis of three-dimensional flow patterns and the associated heat and mass transfer mechanisms in a fume hood enclosure. The flow enters the hood through the front window opening (positive x-direction) and leaves the cupboard through an opening on the top of the hood (positive z-direction). The flow was assumed to be fully turbulent. The flow pattern for different sash openings were studied. The flow pattern around an object located at the bottom of the hood was studied for different locations of the object. It was found that air entering the hood proceeds directly to the back wall, impinges it and turns upward toward the top wall and exits through the outlet. The flow finds its way around any object forming a recirculating region at its training surface. With an increase in the sash opening, the velocity becomes higher and the fluid traces the path to the outlet more quickly. The volume occupied by recirculating flow decreases with increase in sash opening. Both temperature and concentration were found to be maximum near the source and gradually decreased as the heated air or gaseous contaminant entrained with incoming air. The local concentration decreased with increase in sash opening area. The results will be very useful to design experiments with optimum sash opening providing adequate disposal of contaminants with minimum use of conditioned air inside the room

  12. Comparison of different modeling approaches to simulate contaminant transport in a fractured limestone aquifer

    DEFF Research Database (Denmark)

    Mosthaf, Klaus; Rosenberg, L.; Balbarini, Nicola

    . Given available field data and model purpose, this paper therefore aims to develop, examine and compare modeling approaches for transport of contaminants in fractured limestone aquifers. The model comparison was conducted for a contaminated site in Denmark, where a plume of a dissolved contaminant (PCE...... was combined with an analysis of heterogeneities and fractures from a nearby excavation (analog site). Methods for translating the geological information and fracture mapping into each of the model concepts were examined. Each model was compared with available field data, considering both model fit...... of field data is the determination of relevant hydraulic properties and interpretation of aqueous and solid phase contaminant concentration sampling data. Traditional water sampling has a bias towards fracture sampling, however concentrations in the limestone matrix are needed for assessing contaminant...

  13. THEORETICAL AND EXPERIMENTAL MODELING OF MULTI-SPECIES TRANSPORT IN SOILS UNDER ELECTRIC FIELDS

    Science.gov (United States)

    Electrokinetics employs the use of electrodes implanted in soils-contaminated media. Electrodes are supplied with direct current (dc) facilitating ionic transport and subsequent removal. This project investigates the feasibility and efficiency of electrokinetic transport of lea...

  14. Modelling water and contaminant transport in the Rum Jungle Mine overburden heaps

    International Nuclear Information System (INIS)

    Pantelis, G.

    1987-04-01

    An outline is given of a computer model for water and contaminant transport in and around overburden heaps, with those at the Rum Jungle mine site as a specific example. The model assumes the heaps to lie on a sloping shallow aquifer with identical hydraulic properties. The simulation is carried out for a 40 year period. After the first 20 years a cover which is effectively impermeable to infiltrating rainwater and air is introduced on the heap. The restriction of oxygen supply to the heap terminates contaminant production which results from oxidation of pyrite. Leaching of contaminants from the heap in the following 20-year period is examined

  15. Modeling the emission, transport and deposition of contaminated dust from a mine tailing site.

    Science.gov (United States)

    Stovern, Michael; Betterton, Eric A; Sáez, A Eduardo; Villar, Omar Ignacio Felix; Rine, Kyle P; Russell, Mackenzie R; King, Matt

    2014-01-01

    Mining operations are potential sources of airborne particulate metal and metalloid contaminants through both direct smelter emissions and wind erosion of mine tailings. The warmer, drier conditions predicted for the Southwestern US by climate models may make contaminated atmospheric dust and aerosols increasingly important, due to potential deleterious effects on human health and ecology. Dust emissions and dispersion of contaminants from the Iron King Mine tailings in Dewey-Humboldt, Arizona, a Superfund site, are currently being investigated through in situ field measurements and computational fluid dynamics modeling. These tailings are significantly contaminated with lead and arsenic with an average soil concentration of 1616 and 1420 ppm, respectively. Similar levels of these contaminants have also been measured in soil samples taken from the area surrounding the mine tailings. Using a computational fluid dynamics model, we have been able to model dust transport from the mine tailings to the surrounding region. The model includes a distributed Eulerian model to simulate fine aerosol transport and a Lagrangian approach to model fate and transport of larger particles. In order to improve the accuracy of the dust transport simulations both regional topographical features and local weather patterns have been incorporated into the model simulations.

  16. Impacts of Spatio-Variability of Source Morphology on Field-Scale Predictions of Subsurface Contaminant Transport

    National Research Council Canada - National Science Library

    Hatfield, Kirk

    1998-01-01

    ... (organic immiscible liquids distribution and composition) and aquifer properties on predicting solute transport in saturated groundwater systems contaminated with residual Organic Immiscible Liquids (OIL's...

  17. Organic contaminant transport and fate in the subsurface: evolution of knowledge and understanding

    Science.gov (United States)

    Essaid, Hedeff I.; Bekins, Barbara A.; Cozzarelli, Isabelle M.

    2015-01-01

    Toxic organic contaminants may enter the subsurface as slightly soluble and volatile nonaqueous phase liquids (NAPLs) or as dissolved solutes resulting in contaminant plumes emanating from the source zone. A large body of research published in Water Resources Research has been devoted to characterizing and understanding processes controlling the transport and fate of these organic contaminants and the effectiveness of natural attenuation, bioremediation, and other remedial technologies. These contributions include studies of NAPL flow, entrapment, and interphase mass transfer that have advanced from the analysis of simple systems with uniform properties and equilibrium contaminant phase partitioning to complex systems with pore-scale and macroscale heterogeneity and rate-limited interphase mass transfer. Understanding of the fate of dissolved organic plumes has advanced from when biodegradation was thought to require oxygen to recognition of the importance of anaerobic biodegradation, multiple redox zones, microbial enzyme kinetics, and mixing of organic contaminants and electron acceptors at plume fringes. Challenges remain in understanding the impacts of physical, chemical, biological, and hydrogeological heterogeneity, pore-scale interactions, and mixing on the fate of organic contaminants. Further effort is needed to successfully incorporate these processes into field-scale predictions of transport and fate. Regulations have greatly reduced the frequency of new point-source contamination problems; however, remediation at many legacy plumes remains challenging. A number of fields of current relevance are benefiting from research advances from point-source contaminant research. These include geologic carbon sequestration, nonpoint-source contamination, aquifer storage and recovery, the fate of contaminants from oil and gas development, and enhanced bioremediation.

  18. Experimental constraints on transport from dimensionless parameter scaling studies

    International Nuclear Information System (INIS)

    Petty, C.C.; Luce, T.C.; Baker, D.R.

    1998-02-01

    The scalings of heat transport with safety factor (q), normalized collisionality (v), plasma beta (β), and relative gyroradius (ρ*) have been measured on the DIII-D tokamak. The measured ρ* β and v scalings of heat transport indicate that E x B transport from drive wave turbulence is a plausible basis for anomalous transport. For high confinement (H) mode plasmas where the safety factor was varied at fixed magnetic shear, the effective (or one-fluid) thermal diffusivity was found to scale like χ eff ∝ q 2.3±0.64 , with the ion and electron fluids having the same q scaling to within the experimental errors except near the plasma edge. The scaling of the thermal confinement time with safety factor was in good agreement with this local transport dependence, τ th ∝ q -2.42±0.31 ; however, when the magnetic shear was allowed to vary to keep q 0 fixed during the (edge) safety factor scan, a weaker global dependence was observed, τ th ∝ q 95 -1.43±0.23 . This weaker dependence was mainly due to the change in the local value of q between the two types of scans. The combined ρ*, β, v and q scalings of heat transport for H-mode plasmas on DIII-D reproduce the empirical confinement scaling using physical (dimensionless) parameters with the exception of weaker power degradation

  19. Experimental constraints on transport from dimensionless parameter scaling studies

    International Nuclear Information System (INIS)

    Petty, C.C.; Luce, T.C.; Baker, D.R.; Ballet, B.; Carlstrom, T.N.; Cordey, J.G.; DeBoo, J.C.; Gohil, P.; Groebner, R.J.; Rice, B.W.; Thomas, D.M.; Wade, M.R.; Waltz, R.E.

    1998-01-01

    The scalings of heat transport with safety factor (q), normalized collisionality (ν), plasma beta (β), and relative gyroradius (ρ * ) have been measured on the DIII-D tokamak [Fusion Technol. 8, 441 (1985)]. The measured ρ * , β and ν scalings of heat transport indicate that ExB transport from drift wave turbulence is a plausible basis for anomalous transport. For high confinement (H) mode plasmas where the safety factor was varied at fixed magnetic shear, the effective (or one-fluid) thermal diffusivity was found to scale like χ eff ∝q 2.3±0.64 , with the ion and electron fluids having the same q scaling to within the experimental errors except near the plasma edge. The scaling of the thermal confinement time with safety factor was in good agreement with this local transport dependence, τ th ∝q -2.42±0.31 ; however, when the magnetic shear was allowed to vary to keep q 0 fixed during the (edge) safety factor scan, a weaker global dependence was observed, τ th ∝q 95 -1.43±0.23 . This weaker dependence was mainly due to the change in the local value of q between the two types of scans. The combined ρ * , β , ν and q scalings of heat transport for H-mode plasmas on DIII-D reproduce the empirical confinement scaling using physical (dimensional) parameters with the exception of weaker power degradation. copyright 1998 American Institute of Physics

  20. Feed gas contaminant control in ion transport membrane systems

    Science.gov (United States)

    Carolan, Michael Francis [Allentown, PA; Minford, Eric [Laurys Station, PA; Waldron, William Emil [Whitehall, PA

    2009-07-07

    Ion transport membrane oxidation system comprising an enclosure having an interior and an interior surface, inlet piping having an internal surface and adapted to introduce a heated feed gas into the interior of the enclosure, and outlet piping adapted to withdraw a product gas from the interior of the enclosure; one or more planar ion transport membrane modules disposed in the interior of the enclosure, each membrane module comprising mixed metal oxide material; and a preheater adapted to heat a feed gas to provide the heated feed gas to the inlet piping, wherein the preheater comprises an interior surface. Any of the interior surfaces of the enclosure, the inlet piping, and the preheater may be lined with a copper-containing metal lining. Alternatively, any of the interior surfaces of the inlet piping and the preheater may be lined with a copper-containing metal lining and the enclosure may comprise copper.

  1. DNA-labeled micro- and nanoparticles: a new approach to study contaminant transport in the subsurface

    Science.gov (United States)

    McNew, C.; Wang, C.; Kocis, T. N.; Murphy, N. P.; Dahlke, H. E.

    2017-12-01

    Though our understanding of contaminant behavior in the subsurface has improved, our ability to measure and predict complex contaminant transport pathways at hillslope to watershed scales is still lacking. By utilizing bio-molecular nanotechnology developed for nano-medicines and drug delivery, we are able to produce DNA-labeled micro- and nanoparticles for use in a myriad of environmental systems. Control of the fabrication procedure allows us to produce particles of custom size, charge, and surface functionality to mimic the transport properties of the particulate contaminant or colloid of interest. The use of custom sequenced DNA allows for the fabrication of an enormous number of unique particle labels (approximately 1.61 x 1060 unique sequences) and the ability to discern between varied spatial and temporal applications, or the transport effect of varied particle size, charge, or surface properties. To date, this technology has been utilized to study contaminant transport from lab to field scales, including surface and open channel flow applications, transport in porous media, soil retention, and even subglacial flow pathways. Here, we present the technology for production and detection of the DNA-labeled particles along with the results from a current hillslope study at the Sierra Foothills Research and Extension Center (SFREC). This field study utilizes spatial and temporal variations in DNA-labeled particle applications to identify subsurface pollutant transport pathways through the four distinct soil horizons present at the SFREC site. Results from this and previous studies highlight the tremendous potential of the DNA-labeled particle technology for studying contaminant transport through the subsurface.

  2. Field validation of the contaminant transport model, FEMA

    International Nuclear Information System (INIS)

    Wong, K.-F.V.

    1986-01-01

    The work describes the validation with field data of a finite element model of material transport through aquifers (FEMA). Field data from the Idaho Chemical Processing Plant, Idaho, USA and from the 58th Street landfill in Miami, Florida, USA are used. In both cases the model was first calibrated and then integrated over a span of eight years to check on the predictive capability of the model. Both predictive runs gave results that matched well with available data. (author)

  3. Evaluation of Different Modeling Approaches to Simulate Contaminant Transport in a Fractured Limestone Aquifer

    Science.gov (United States)

    Mosthaf, K.; Rosenberg, L.; Balbarini, N.; Broholm, M. M.; Bjerg, P. L.; Binning, P. J.

    2014-12-01

    It is important to understand the fate and transport of contaminants in limestone aquifers because they are a major drinking water resource. This is challenging because they are highly heterogeneous; with micro-porous grains, flint inclusions, and being heavily fractured. Several modeling approaches have been developed to describe contaminant transport in fractured media, such as the discrete fracture (with various fracture geometries), equivalent porous media (with and without anisotropy), and dual porosity models. However, these modeling concepts are not well tested for limestone geologies. Given available field data and model purpose, this paper therefore aims to develop, examine and compare modeling approaches for transport of contaminants in fractured limestone aquifers. The model comparison was conducted for a contaminated site in Denmark, where a plume of a dissolved contaminant (PCE) has migrated through a fractured limestone aquifer. Multilevel monitoring wells have been installed at the site and available data includes information on spill history, extent of contamination, geology and hydrogeology. To describe the geology and fracture network, data from borehole logs was combined with an analysis of heterogeneities and fractures from a nearby excavation (analog site). Methods for translating the geological information and fracture mapping into each of the model concepts were examined. Each model was compared with available field data, considering both model fit and measures of model suitability. An analysis of model parameter identifiability and sensitivity is presented. Results show that there is considerable difference between modeling approaches, and that it is important to identify the right one for the actual scale and model purpose. A challenge in the use of field data is the determination of relevant hydraulic properties and interpretation of aqueous and solid phase contaminant concentration sampling data. Traditional water sampling has a bias

  4. THE INTERPLAY BETWEEN GEOCHEMICAL REACTIONS AND ADVECTION-DISPERSION IN CONTAMINANT TRANSPORT AT A URANIUM MILL TAILINGS SITE

    Science.gov (United States)

    It is well known that the fate and transport of contaminants in the subsurface are controlled by complex processes including advection, dispersion-diffusion, and chemical reactions. However, the interplay between the physical transport processes and chemical reactions, and their...

  5. Contaminant fate and transport in the Venice Lagoon: results from a multi-segment multimedia model.

    Science.gov (United States)

    Sommerfreund, J K; Gandhi, N; Diamond, M L; Mugnai, C; Frignani, M; Capodaglio, G; Gerino, M; Bellucci, L G; Giuliani, S

    2010-03-01

    Contaminant loadings to the Venice Lagoon peaked from 1950s-1980s and although they have since declined, contaminant concentrations remain elevated in sediment and seafood. In order to identify the relative importance of contaminant sources, inter-media exchange and removal pathways, a modified 10-segment fugacity/aquivalence-based model was developed for octachlorodibenzodioxin/furan (OCDD/F), PCB-180, Pb and Cu in the Venice Lagoon. Results showed that in-place pollution nearby the industrial area, current industrial discharges, and tributary loadings were the main sources of contaminants to the lagoon, with negligible contributions from the atmosphere. The fate of these contaminants was governed by sediment-water exchange with simultaneous advective transport by water circulation. Contaminants circulated amongst the northern and central basins with a small fraction reaching the far southern basin and the Chioggia inlet. As a consequence, we estimated limited contaminant transfer to the Adriatic Sea, trapping the majority of contaminants in the sediment in this "average" circulation scenario which does not account for periodic flooding events. (c) 2009 Elsevier Inc. All rights reserved.

  6. A system for the study of molecular contamination. [experimental vacuum chambers

    Science.gov (United States)

    Dillow, C. F.; Allen, T. H.; Linford, R. M. F.; Richmond, R. G.

    1975-01-01

    An experimental vacuum chambers was designed and fabricated to provide a wide range of experimental capability. This work chamber assembly (WCA) was conceived to establish the proof-of-principle of various techniques for studying the kinetics of contaminants and their effects. It incorporates the capability for depositing both optical and contaminant films on temperature-controlled samples, and for in-situ measurements of the vacuum ultraviolet reflectance. Ellipsometer optics are mounted on the chamber for film thickness determinations, and other features include access ports for radiation sources and instrumentation.

  7. Mathematical simulation of sediment and contaminant transport in surface waters. Annual report, October 1977--September 1978

    International Nuclear Information System (INIS)

    Onishi, Y.; Arnold, E.M.; Serne, R.J.; Cowan, C.E.; Thompson, F.L.; Mayer, D.W.

    1979-01-01

    Various pathways exist for exposure of humans and biota to radioactive materials released from nuclear facilities. Hydrologic transport (liquid pathway) is one element in the evaluation of the total radiation dose to man. Mathematical models supported by well-planned field data collection programs can be useful tools in assessing the hydrologic transport and ultimate fate of radionuclides. Radionuclides with high distribution coefficients or radionuclides in surface waters with high suspended sediment concentrations are, to a great extent, adsorbed by river and marine sediments. Thus, otherwise dilute contaminants are concentrated. Contaminated sediments may be deposited on the river and ocean beds creating a significant pathway to man. Contaminated bed sediment in turn may become a long-term source of pollution through desorption and resuspension. In order to assess migration and accumulation of radionuclides in surface waters, mathematical models must correctly simulate essential mechanisms of radionuclide transport. The objectives of this study were: (1) to conduct a critical review of (a) radionuclide transport models as well as sediment transport and representative water quality models in rivers, estuaries, oceans, lakes, and reservoirs, and (b) adsorption and desorption mechanisms of radionuclides with sediments in surface waters; (2) to synthesize a mathematical model capable of predicting short- and long-term transport and accumulation of radionuclides in marine environments

  8. CFD Simulations of Contaminant Transport between two Breathing Persons

    DEFF Research Database (Denmark)

    Bjørn, Erik; Nielsen, Peter V.

    Experiments have shown that exhalation from one person is able to penetrate the breathing zone of another person at a distance. Computational Fluid Dynamics (CFD) is used to investigate the dependency of the personal exposure on some physical parameters, namely: Pulmonary ventilation rate......, convective heat output, exhalation temperature, and crosssectional exhalation area. Full-scale experimental results are used to calibrate/validate the CFD model....

  9. Anthropogenic contamination of a phreatic drinking water winning: 3-dimensional reactive transport modelling

    NARCIS (Netherlands)

    Griffioen, J.|info:eu-repo/dai/nl/091129265; van der Grift, B.|info:eu-repo/dai/nl/373433484; Maas, D.; van den Brink, C.|info:eu-repo/dai/nl/187443416; Zaadnoordijk, J. W.

    2003-01-01

    Groundwater is contaminated at the regional scale by agricultural activities and atmospheric deposition. A 3-D transport model was set-up for a phreatic drinking water winning, where the groundwater composition was monitored accurately. The winning is situated at an area with unconsolidated

  10. Sensitivity Analysis of Unsaturated Flow and Contaminant Transport with Correlated Parameters

    Science.gov (United States)

    Relative contributions from uncertainties in input parameters to the predictive uncertainties in unsaturated flow and contaminant transport are investigated in this study. The objectives are to: (1) examine the effects of input parameter correlations on the sensitivity of unsaturated flow and conta...

  11. Transport from diffuse sources of contamination and its application to a coupled unsaturated - saturated system

    NARCIS (Netherlands)

    Ommen, van H.C.

    1988-01-01

    A simple theory to predict groundwater quality upon contamination from diffuse sources was developed. It appeared that an analogy exists between the predominant transport phenomena and the reaction of a reservoir, in which perfect mixing takes place. Such an analogy enables a simple

  12. Techniques to better understand complex epikarst hydrogeology and contaminant transport in telogenetic karst settings

    Science.gov (United States)

    The movement of autogenic recharge through the shallow epikarstic zone in soil-mantled karst aquifers is important in understanding recharge areas and rates, groundwater storage, and contaminant transport processes. The groundwater flow in agricultural karst areas, such as Kentucky’s Pennyroyal Plat...

  13. Grand challenge problems in environmental modeling and remediation: groundwater contaminant transport

    Energy Technology Data Exchange (ETDEWEB)

    Todd Arbogast; Steve Bryant; Clint N. Dawson; Mary F. Wheeler

    1998-08-31

    This report describes briefly the work of the Center for Subsurface Modeling (CSM) of the University of Texas at Austin (and Rice University prior to September 1995) on the Partnership in Computational Sciences Consortium (PICS) project entitled Grand Challenge Problems in Environmental Modeling and Remediation: Groundwater Contaminant Transport.

  14. Importance of hydrological parameters in contaminant transport modeling in a terrestrial environment

    International Nuclear Information System (INIS)

    Tsuduki, Katsunori; Matsunaga, Takeshi

    2007-01-01

    A grid type multi-layered distributed parameter model for calculating discharge in a watershed was described. Model verification with our field observation resulted in different sets of hydrological parameter values, all of which reproduced the observed discharge. The effect of those varied hydrological parameters on contaminant transport calculation was examined and discussed by simulation of event water transfer. (author)

  15. Contaminant transport in soils and its significance in the design of waste management facilities

    International Nuclear Information System (INIS)

    Barbour, S.L.; Krahn, J.

    1984-01-01

    Transport of contaminants in soils is governed by advection, dispersion, geochemical mass transfer and decay in the case of radioactive materials. Advection is the process whereby the contaminant is being carried along by moving water. Dispersion arises from mechanical mixing due to velocity distributions between soil particles and molecular diffusion. Geochemical mass transfer retards the migration because of adsorption and/or precipitation. Decay results in a decrease of contaminant concentrations for radioactive materials. Studies on the effectiveness of a cutoff wall in granular soils beneath a tailings dyke show that the most important parameter is the groundwater flow velocity. It not only controls the advective transport but also directly affects the dispersive component and the attenuation that may be obtained through adsorption and decay

  16. 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

  17. 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.

  18. A cellular automaton simulation of contaminant transport in porous media

    International Nuclear Information System (INIS)

    Freed, D.M.; Simonson, S.A.

    1995-01-01

    A simulation tool to investigate radionuclide transport in porous groundwater flow is described. The flow systems of interest are those important in determining the fate of radionuclides emplaced in an underground repository, such as saturated matrix flow, matrix and fracture flow in the unsaturated zone, and viscous fingering in porous fractures. The work discussed here is confined to consideration of saturated flow in porous media carrying a dilute, sorptive species. The simulation technique is based on a special class of cellular automata known as lattice gas automata (LGA) which are capable of predicting hydrodynamic behavior. The original two-dimensional scheme (that of Frisch et. al. known as the FHP model) used particles of unit mass traveling on a triangular lattice with unit velocity and undergoing simple collisions which conserve mass and momentum at each node. These microscopic rules go over to the incompressible Navier-Stokes equations in the macroscopic limit. One of the strengths of this technique is the natural way that heterogeneities, such as boundaries, are accommodated. Complex geometries such as those associated with porous microstructures can be modeled effectively. Several constructions based on the FHP model have been devised, including techniques to eliminate statistical noise, extension to three dimensions, and the addition of surface tension which leads to multiphase flow

  19. Recent developments on surface contamination limits for packages and conveyances in transport regulations

    International Nuclear Information System (INIS)

    Thierfeldt, S.; Woerlen, S.; Lorenz, B.; Schwarz, W.

    2009-01-01

    The IAEA Regulations for the Safe Transport of Radioactive Material [1] contain requirements for contamination limits on packages and conveyances used for the transport of radioactive material. Current contamination limits for packages and conveyances under routine transport conditions have been derived from a model proposed by Fairbairn nearly 50 years ago [3]. This model has proven effective if used with pragmatism, but is based on very conservative as well as extremely simple assumptions which is in no way appropriate any more and which is not compatible with ICRP recommendations regarding radiation protection standards. Therefore, a new model has been developed over the last 8 years which reflects all steps of the transport process. The derivation of this model has been fostered by the IAEA by initiating a Co-ordinated Research Project (see section 2). The results of the calculations using this model could be directly applied as new nuclide specific transport limits for the non-fixed contamination. A corresponding regulatory text has been drafted by an IAEA technical meeting TM-36514, which was held in Tokyo November 10-14, 2008 (see section 4). (orig.)

  20. Recent developments on surface contamination limits for packages and conveyances in transport regulations

    Energy Technology Data Exchange (ETDEWEB)

    Thierfeldt, S.; Woerlen, S. [Brenk Systemplanung GmbH, Aachen (Germany); Lorenz, B. [GNS Gesellschaft fuer Nuklear-Service mbH, Essen (Germany); Schwarz, W. [VGB PowerTech e.V., Essen (Germany)

    2009-07-01

    The IAEA Regulations for the Safe Transport of Radioactive Material [1] contain requirements for contamination limits on packages and conveyances used for the transport of radioactive material. Current contamination limits for packages and conveyances under routine transport conditions have been derived from a model proposed by Fairbairn nearly 50 years ago [3]. This model has proven effective if used with pragmatism, but is based on very conservative as well as extremely simple assumptions which is in no way appropriate any more and which is not compatible with ICRP recommendations regarding radiation protection standards. Therefore, a new model has been developed over the last 8 years which reflects all steps of the transport process. The derivation of this model has been fostered by the IAEA by initiating a Co-ordinated Research Project (see section 2). The results of the calculations using this model could be directly applied as new nuclide specific transport limits for the non-fixed contamination. A corresponding regulatory text has been drafted by an IAEA technical meeting TM-36514, which was held in Tokyo November 10-14, 2008 (see section 4). (orig.)

  1. Disposition of TA-33-21, a plutonium contaminated experimental facility

    International Nuclear Information System (INIS)

    Cox, E.J.; Garde, R.; Valentine, A.M.

    1975-01-01

    The report discusses the decontamination, demolition and disposal of a plutonium contaminated experimental physics facility which housed physics experiments with plutonium from 1951 until 1960. The results of preliminary decontamination efforts in 1960 are reported along with health physics, waste management, and environmental aspects of final disposition work accomplished during 1974 and 1975. (auth)

  2. Simplified estimation technique for organic contaminant transport in ground water

    Energy Technology Data Exchange (ETDEWEB)

    Piver, W T; Lindstrom, F T

    1984-05-01

    The analytical solution for one-dimensional dispersive-advective transport of a single solute in a saturated soil accompanied by adsorption onto soil surfaces and first-order reaction rate kinetics for degradation can be used to evaluate the suitability of potential sites for burial of organic chemicals. The technique can be used to the greatest advantage with organic chemicals that are present in ground waters in small amounts. The steady-state solution provides a rapid method for chemical landfill site evaluation because it contains the important variables that describe interactions between hydrodynamics and chemical transformation. With this solution, solute concentration, at a specified distance from the landfill site, is a function of the initial concentration and two dimensionless groups. In the first group, the relative weights of advective and dispersive variables are compared, and in the second group the relative weights of hydrodynamic and degradation variables are compared. The ratio of hydrodynamic to degradation variables can be rearranged and written as (a/sub L lambda)/(q/epsilon), where a/sub L/ is the dispersivity of the soil, lambda is the reaction rate constant, q is ground water flow velocity, and epsilon is the soil porosity. When this term has a value less than 0.01, the degradation process is occurring at such a slow rate relative to the hydrodynamics that it can be neglected. Under these conditions the site is unsuitable because the chemicals are unreactive, and concentrations in ground waters will change very slowly with distance away from the landfill site.

  3. The effect of precipitation on contaminant dissolution and transport: Analytic solutions

    International Nuclear Information System (INIS)

    Light, W.B.; Chambre, P.L.; Pigford, T.H.; Lee, W.W.L.

    1988-09-01

    We analysed the effect of precipitation on the dissolution and transport rates of a nondecaying contaminant. Precipitation near the waste surface can have a profound effect on dissolution and transport rates. The mass-transfer rate at the waste surface is controlled by the solid-liquid reaction rate to an extent determined by the modified reaction-rate modulus, α. At later times extending to steady state, the mass-transfer rate depends on the location of the precipitation front r/sub p/ and on the solubility ratio C/sub o//C/sub p/. A precipitation front very near the waste surface can change the dissolution mechanism from solubility-diffusion-controlled to chemical-reaction-rate controlled. Precipitation limits the concentration of the contaminant at r > r/sub p/ to C/sub p/, steepening the concentration gradient for dissolution on the waste package side of the front and flattening the gradient for transport in the region outside the front. This increases the rate of contaminant transport from the waste to the front while decreasing the rate of transport away from the front, when compared to the situation without precipitation. The difference in the transport rates at the front is the rate of precipitation. For large changes in solubility, most of the contaminant is immobilized by precipitation, as was observed in a parallel study. The effect of a precipitation front located nearby in surrounding rock is to increase the release rate at the waste surface/rock interface. The increase in release rate at the waste surface is greater the closer the precipitation and the larger the ratio C/sub o//C/sub p/, also observed by others. The release rates of other waste constituents that dissolve congruently with the solubility-controlling matrix can be increased by a local high-solubility region between the waste surface and the precipitation front. 10 refs., 5 figs

  4. The shielding properties of the newly developed container for transport of samples contaminated with CBRN substances

    International Nuclear Information System (INIS)

    Fisera, O.; Kares, J.

    2014-01-01

    A container for transport of environmental samples to the analytical laboratory is being developed as part of the development of system for collection and transport of samples contaminated with chemical, biological, radioactive and nuclear (CBRN) substances after CBRN incidents. The proposed system corresponds with current requirements of NATO publication AEP-66. The proposed container will meet the requirements of mechanical stability and tightness for the packaging of the chemical, biological and radioactive substances. Verification of shielding properties and satisfaction of requirements of radiation protection during transport of potentially relatively high active samples was the aim of this part of research. The results, together with a wall thickness of the inner steel container, the inner lining and the outer transport package, give excellent assumption that the radiation protection requirements for the proposed container and transport package will be satisfied. (authors)

  5. Contaminant transport, revegetation, and trace element studies at inactive uranium mill tailings piles

    International Nuclear Information System (INIS)

    Dreesen, D.R.; Marple, M.L.; Kelley, N.E.

    1978-01-01

    The stabilization of inactive uranium mill tailings piles is presently under study. These studies have included investigations of stabilizing tailings by attempting to establish native vegetation without applying irrigation. Examination of processes which transport tailings or associated contaminants into the environment has been undertaken to better understand the containment provided by various stabilization methods. The uptake of toxic trace elements and radionuclides by vegetation has been examined as a mechanism of contaminant transport. The source terms of 222 Rn from inactive piles have been determined as well as the attenuation of radon flux provided by shallow soil covers. The possibility of shallow ground water contamination around an inactive pile has been examined to determine the significance of ground water transport as a mode of contaminant migration. The rationale in support of trace element studies related to uranium milling activities is presented including the enrichment, migration, and toxicities of trace elements often associated with uranium deposits. Some concepts for the stabilization of inactive piles are presented to extrapolate from research findings to practical applications. 25 references, 8 tables

  6. Behavioral response to contamination risk information in a spatially explicit groundwater environment: Experimental evidence

    Science.gov (United States)

    Li, Jingyuan; Michael, Holly A.; Duke, Joshua M.; Messer, Kent D.; Suter, Jordan F.

    2014-08-01

    This paper assesses the effectiveness of aquifer monitoring information in achieving more sustainable use of a groundwater resource in the absence of management policy. Groundwater user behavior in the face of an irreversible contamination threat is studied by applying methods of experimental economics to scenarios that combine a physics-based, spatially explicit, numerical groundwater model with different representations of information about an aquifer and its risk of contamination. The results suggest that the threat of catastrophic contamination affects pumping decisions: pumping is significantly reduced in experiments where contamination is possible compared to those where pumping cost is the only factor discouraging groundwater use. The level of information about the state of the aquifer also affects extraction behavior. Pumping rates differ when information that synthesizes data on aquifer conditions (a "risk gauge") is provided, despite invariant underlying economic incentives, and this result does not depend on whether the risk information is location-specific or from a whole aquifer perspective. Interestingly, users increase pumping when the risk gauge signals good aquifer status compared to a no-gauge treatment. When the gauge suggests impending contamination, however, pumping declines significantly, resulting in a lower probability of contamination. The study suggests that providing relatively simple aquifer condition guidance derived from monitoring data can lead to more sustainable use of groundwater resources.

  7. Metal Contamination of the Natural Environment in Norway from Long Range Atmospheric Transport

    International Nuclear Information System (INIS)

    Steinnes, E.

    2001-01-01

    Long range atmospheric transport is the most important source of contamination to the natural environment in Norway with many heavy metals. Investigations based on aerosol studies, bulk deposition measurements and moss analysis show that airborne transport from other parts of Europe is the major mode for supply of vanadium, zinc, arsenic, selenium, molybdenum, cadmium, tin,antimony, tellurium, thallium, lead, and bismuth, whereas metals such as chromium, nickel, and copper are mainly derived from point sources within Norway and in northwestern Russia close to the Norwegian border. Elements associated with long range transport show substantial enrichment in the humus horizon of natural soils in southern Norway, sometimes to levels suspected to cause effects on soil microbial processes. E.g. lead concentration values of 150-200 ppm are observed in the most contaminated areas in the south as compared to about 5 ppm in the far north. Elements such as lead and cadmium also show enrichment in some terrestrial food chains. These elements also show considerably elevated levels over background concentrations in the water and sediment of small lakes in the southern part of the country. Retrospective studies based on ombrogenous peatcores indicate that long range transport has been a significant source of heavy metal contamination in southern Norway for the last couple of centuries. The deposition of most heavy metals in Norway has been considerably reduced over the last 20 yr, with the exception of contributions in the north from Russian smelters

  8. Experimental Studies of the Transport Parameters of Warm Dense Matter

    Energy Technology Data Exchange (ETDEWEB)

    Chouffani, Khalid [Idaho State Univ., Pocatello, ID (United States)

    2014-12-01

    There is a need to establish fundamental properties of matter and energy under extreme physical conditions. Although high energy density physics (HEDP) research spans a wide range of plasma conditions, there is one unifying regime that is of particular importance and complexity: that of warm dense matter, the transitional state between solid state condensed matter and energetic plasmas. Most laboratory experimental conditions, including inertial confinement implosion, fall into this regime. Because all aspects of laboratory-created high-energy-density plasmas transition through the warm dense matter regime, understanding the fundamental properties to determine how matter and energy interact in this regime is an important aspect of major research efforts in HEDP. Improved understanding of warm dense matter would have significant and wide-ranging impact on HEDP science, from helping to explain wire initiation studies on the Sandia Z machine to increasing the predictive power of inertial confinement fusion modeling. The central goal or objective of our proposed research is to experimentally determine the electrical resistivity, temperature, density, and average ionization state of a variety of materials in the warm dense matter regime, without the use of theoretical calculations. Since the lack of an accurate energy of state (EOS) model is primarily due to the lack of experimental data, we propose an experimental study of the transport coefficients of warm dense matter.

  9. Reduction of spatial distribution of risk factors for transportation of contaminants released by coal mining activities.

    Science.gov (United States)

    Karan, Shivesh Kishore; Samadder, Sukha Ranjan

    2016-09-15

    It is reported that water-energy nexus composes two of the biggest development and human health challenges. In the present study we presented a Risk Potential Index (RPI) model which encapsulates Source, Vector (Transport), and Target risks for forecasting surface water contamination. The main aim of the model is to identify critical surface water risk zones for an open cast mining environment, taking Jharia Coalfield, India as the study area. The model also helps in feasible sampling design. Based on spatial analysis various risk zones were successfully delineated. Monthly RPI distribution revealed that the risk of surface water contamination was highest during the monsoon months. Surface water samples were analysed to validate the model. A GIS based alternative management option was proposed to reduce surface water contamination risk and observed 96% and 86% decrease in the spatial distribution of very high risk areas for the months June and July respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Packaging, Transportation, and Disposal Logistics for Large Radioactively Contaminated Reactor Decommissioning Components

    International Nuclear Information System (INIS)

    Lewis, Mark S.

    2008-01-01

    The packaging, transportation and disposal of large, retired reactor components from operating or decommissioning nuclear plants pose unique challenges from a technical as well as regulatory compliance standpoint. In addition to the routine considerations associated with any radioactive waste disposition activity, such as characterization, ALARA, and manifesting, the technical challenges for large radioactively contaminated components, such as access, segmentation, removal, packaging, rigging, lifting, mode of transportation, conveyance compatibility, and load securing require significant planning and execution. In addition, the current regulatory framework, domestically in Titles 49 and 10 and internationally in TS-R-1, does not lend itself to the transport of these large radioactively contaminated components, such as reactor vessels, steam generators, reactor pressure vessel heads, and pressurizers, without application for a special permit or arrangement. This paper addresses the methods of overcoming the technical and regulatory challenges. The challenges and disposition decisions do differ during decommissioning versus component replacement during an outage at an operating plant. During decommissioning, there is less concern about critical path for restart and more concern about volume reduction and waste minimization. Segmentation on-site is an available option during decommissioning, since labor and equipment will be readily available and decontamination activities are routine. The reactor building removal path is also of less concern and there are more rigging/lifting options available. Radionuclide assessment is necessary for transportation and disposal characterization. Characterization will dictate the packaging methodology, transportation mode, need for intermediate processing, and the disposal location or availability. Characterization will also assist in determining if the large component can be transported in full compliance with the transportation

  11. Analytical analysis of soil-moisture and trace-contaminant transport

    International Nuclear Information System (INIS)

    Larson, N.M.; Reeves, M.

    1976-03-01

    A transport model is presented which predicts the coupled movement of both water and trace contaminants through a layered and unsaturated soil-moisture zone. In order to achieve computation speeds suitable for watershed implementations, moisture properties are approximated as exponential functions of pressure head, and lateral flows are treated as sinks in a basically vertical one-dimensional analysis. In addition, only advection by the Darcy-flow velocities and linear adsorption by the soil matrix are considered in depicting movement of the trace contaminant. Formal solution of the resulting transport equations is obtained through use of both eigenfunction-expansion and coordinate-transformation methods. Numerical solution is effected by means of a program written in FORTRAN IV and implemented on an IBM 360/91 computer. Two example calculations illustrate both strengths and weaknesses of our model

  12. Metropol: A computer code for the simulation of transport of contaminants with groundwater

    International Nuclear Information System (INIS)

    Sauter, F.J.; Hassanizadeh, S.M.; Leijnse, A.; Glasbergen, P.; Slot, A.F.M.

    1990-01-01

    In this report a description is given of the computer code Metropol. This code simulates the three-dimensional flow of groundwater with varying density and the simultaneous transport of contaminants in low concentration and is based on the finite element method. The basic equations for groundwater flow and transport are described as well as the mathematical techniques used to solve these equations. Pre-processing facilities for mesh generation and post-processing facilities such as particle tracking are also discussed. This work was part of the Community Mirage project Second phase, research area Calculation tools

  13. The transport of contaminants during storms in the White Oak Creek and Melton Branch Watersheds

    International Nuclear Information System (INIS)

    Solomon, D.K.; Marsh, J.D.; Wickliff, D.S.; Larsen, I.L.; Clapp, R.B.

    1989-03-01

    This report documents are transport of contaminants from SWSA 5 along two principle pathways: the saturated groundwater system and the intermittently saturated stormflow system. The results of a baseflow sampling effort and a dye tracer study, indicated that much of the transport through the saturated groundwater system occurs along discrete geologic features. These features appear to be related to the contact between the Maryville and Nolichucky members of the Conasauga shale. Three discrete sources of tritium to Melton Branch Stream (MBS) were identified and traced to SWSA 5 by measuring soil moisture and evapotranspiration along transects between MBS and SWSA 5

  14. 3-dimensional self-calibrating coastal oil spill trajectory tracking and contaminant transport using HF radar

    International Nuclear Information System (INIS)

    Ojo, T.O.; Bonner, J.S.

    2002-01-01

    A study was conducted to demonstrate the dynamic behaviour of the turbulent mixing process in coastal environments for both advection and dispersion transport. The spatial variability of the coefficients that characterize the process was also examined. Every transport model should be calibrated to include specific information regarding geomorphology and climatic conditions. HF-radar equipment eliminates the need for model-recalibration and validation for transport models of coefficients which have spatial-temporal variations. The HF-radar has a grid resolution of 1000 m, providing real-time velocity coefficients by measuring surface currents. Dispersion coefficients can be derived from velocity time-series using the principle of Autocorrelation Functions (ACF) for time series. This concept was applied to two Gulf of Mexico bays in Texas, Corpus Christi and Matagorda. It was determined that the within-bay spatial variability of dispersion coefficients were many orders of magnitude higher than between-bay variability. The proposed model effectively reduced model complexity. The results of a 3-D dimensional contaminant transport model was presented. It was successfully used in the simulation of a contaminant spill scenario in the two bays using spatially distributed time-dependent transport coefficients. 5 refs., 8 figs

  15. Testing of a benchscale Reverse Osmosis/Coupled Transport system for treating contaminated groundwater

    International Nuclear Information System (INIS)

    Hodgson, K.M.; Lunsford, T.R.; Panjabi, G.

    1994-01-01

    The Reverse Osmosis/Coupled Transport process is a innovative means of removing radionuclides from contaminated groundwater at the Hanford Site. Specifically, groundwater in the 200 West Area of the Hanford Site has been contaminated with uranium, technetium, and nitrate. Investigations are proceeding to determine the most cost effective method to remove these contaminants. The process described in this paper combines three different membrane technologies (reverse osmosis, coupled transport, and nanofiltration to purify the groundwater while extracting and concentrating uranium, technetium, and nitrate into separate solutions. This separation allows for the future use of the radionuclides, if needed, and reduces the amount of waste that will need to be disposed of. This process has the potential to concentrate the contaminants into solutions with volumes in a ratio of 1/10,000 of the feed volume. This compares to traditional volume reductions of 10 to 100 for ion exchange and stand-alone reverse osmosis. The successful demonstration of this technology could result in significant savings in the overall cost of decontaminating the groundwater

  16. Safety analysis report for packaging onsite long-length contaminated equipment transport system

    International Nuclear Information System (INIS)

    McCormick, W.A.

    1997-01-01

    This safety analysis report for packaging describes the components of the long-length contaminated equipment (LLCE) transport system (TS) and provides the analyses, evaluations, and associated operational controls necessary for the safe use of the LLCE TS on the Hanford Site. The LLCE TS will provide a standardized, comprehensive approach for the disposal of approximately 98% of LLCE scheduled to be removed from the 200 Area waste tanks

  17. Safety analysis report for packaging, onsite, long-length contaminated equipment transport system

    Energy Technology Data Exchange (ETDEWEB)

    McCormick, W.A.

    1997-05-09

    This safety analysis report for packaging describes the components of the long-length contaminated equipment (LLCE) transport system (TS) and provides the analyses, evaluations, and associated operational controls necessary for the safe use of the LLCE TS on the Hanford Site. The LLCE TS will provide a standardized, comprehensive approach for the disposal of approximately 98% of LLCE scheduled to be removed from the 200 Area waste tanks.

  18. Characterization of Contaminant Transport using Naturally-Occurring U-Series Disequilibria - Final Report

    International Nuclear Information System (INIS)

    Murrell, Michael T.; Ku, Teh-Lung

    2001-01-01

    The interactions of mixed wastes containing radionuclides with solid rock surface and the mobility of the radionuclides in aquifer systems depend not only on the chemistry of the nuclides and the physico-chemical effects of radioactive decay, but also on the site-specific hydrogeology. Thus, to characterize contaminant transport, it is best to cross-check figures derived from any small-scale laboratory experiments over limited times with that obtained from field-oriented, natural analog studies. We propose such a study using the naturally-occurring U and Th decay-series disequilibria. The work of ours and other researchers have shown that the parent/daughter disequilibrium patterns existing in groundwater systems can be modeled in terms of local nuclide mass balance to arrive at such information as the rock-water contact time (fluid flow) and rates of contaminant transport, taking into account the retardation effect due to nuclide/rock interaction contaminants at INEL by grouping them into three categories, represented by isotopes of (1) Th and Pa, (2) U and (3) Ra. Mass spectrometric measurements of these elements will be emphasized in order to minimize sample size requirements and to maximize precision. Results will form the data base for a model code for computing: (1) Fluid residence time (transport rates) in the basalt aquifers at various locations, (2) The in-situ adsorption and desorption rate constants, as well as the retardation factors, of various radionuclide wastes, and (3) Rock dissolution rate and its relation to preferential flow and contamination transport in the fractured rock

  19. Transport from diffuse sources of contamination and its application to a coupled unsaturated - saturated system

    OpenAIRE

    Ommen, van, H.C.

    1988-01-01

    A simple theory to predict groundwater quality upon contamination from diffuse sources was developed. It appeared that an analogy exists between the predominant transport phenomena and the reaction of a reservoir, in which perfect mixing takes place. Such an analogy enables a simple incorporation of physico-chemical processes (decomposition, adsorption), as was shown by an illustrative response of the quality of groundwater to an input of a radio-active decaying solute (and its decay...

  20. Uncertainty quantification and experimental design based on unsupervised machine learning identification of contaminant sources and groundwater types using hydrogeochemical data

    Science.gov (United States)

    Vesselinov, V. V.

    2017-12-01

    Identification of the original groundwater types present in geochemical mixtures observed in an aquifer is a challenging but very important task. Frequently, some of the groundwater types are related to different infiltration and/or contamination sources associated with various geochemical signatures and origins. The characterization of groundwater mixing processes typically requires solving complex inverse models representing groundwater flow and geochemical transport in the aquifer, where the inverse analysis accounts for available site data. Usually, the model is calibrated against the available data characterizing the spatial and temporal distribution of the observed geochemical species. Numerous geochemical constituents and processes may need to be simulated in these models which further complicates the analyses. As a result, these types of model analyses are typically extremely challenging. Here, we demonstrate a new contaminant source identification approach that performs decomposition of the observation mixtures based on Nonnegative Matrix Factorization (NMF) method for Blind Source Separation (BSS), coupled with a custom semi-supervised clustering algorithm. Our methodology, called NMFk, is capable of identifying (a) the number of groundwater types and (b) the original geochemical concentration of the contaminant sources from measured geochemical mixtures with unknown mixing ratios without any additional site information. We also demonstrate how NMFk can be extended to perform uncertainty quantification and experimental design related to real-world site characterization. The NMFk algorithm works with geochemical data represented in the form of concentrations, ratios (of two constituents; for example, isotope ratios), and delta notations (standard normalized stable isotope ratios). The NMFk algorithm has been extensively tested on synthetic datasets; NMFk analyses have been actively performed on real-world data collected at the Los Alamos National

  1. Modeling hydrology and reactive transport in roads: The effect of cracks, the edge, and contaminant properties

    International Nuclear Information System (INIS)

    Apul, Defne S.; Gardner, Kevin H.; Eighmy, T. Taylor

    2007-01-01

    The goal of this research was to provide a tool for regulators to evaluate the groundwater contamination from the use of virgin and secondary materials in road construction. A finite element model, HYDRUS2D, was used to evaluate generic scenarios for secondary material use in base layers. Use of generic model results for particular applications was demonstrated through a steel slag example. The hydrology and reactive transport of contaminants were modeled in a two-dimensional cross section of a road. Model simulations showed that in an intact pavement, lateral velocities from the edge towards the centerline may transport contaminants in the base layer. The dominant transport mechanisms are advection closer to the edge and diffusion closer to the centerline. A shoulder joint in the pavement allows 0.03 to 0.45 m 3 /day of infiltration per meter of joint length as a function of the base and subgrade hydrology and the rain intensity. Scenario simulations showed that salts in the base layer of pavements are depleted by 99% in the first 20 years, whereas the metals may not reach the groundwater in 20 years at any significant concentrations if the pavement is built on adsorbing soils

  2. Approach to uncertainty assessment for fluid flow and contaminant transport modeling in heterogeneous groundwater systems

    International Nuclear Information System (INIS)

    Nelson, R.W.; Jacobson, E.A.; Conbere, W.

    1985-06-01

    There is a growing awareness of the need to quantify uncertainty in groundwater flow and transport model results. Regulatory organizations are beginning to request the statistical distributions of predicted contaminant arrival to the biosphere, so that realistic confidence intervals can be obtained for the modeling results. To meet these needs, methods are being developed to quantify uncertainty in the subsurface flow and transport analysis sequence. A method for evaluating this uncertainty, described in this paper, considers uncertainty in material properties and was applied to an example field problem. Our analysis begins by using field measurements of transmissivity and hydraulic head in a regional, parameter estimation method to obtain a calibrated fluid flow model and a covariance matrix of the parameter estimation errors. The calibrated model and the covariance matrix are next used in a conditional simulation mode to generate a large number of 'head realizations.' The specific pore water velocity distribution for each realization is calculated from the effective porosity, the aquifer parameter realization, and the associated head values. Each velocity distribution is used to obtain a transport solution for a contaminant originating from the same source for all realizations. The results are the statistical distributions for the outflow arrival times. The confidence intervals for contamination reaching the biosphere are obtained from the outflow statistical distributions. 20 refs., 12 figs

  3. Experimental analysis of the environmental contamination of electrical equipment; Analisis experimental de la contaminacion ambiental en equipos electricos

    Energy Technology Data Exchange (ETDEWEB)

    Campillo Ruiz, Maria Teresa; Ponce Velez, Marco Antonio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1996-12-31

    This paper is a summary of the main causes that originate the contamination problems in insulating materials. This as the result of different studies performed in experimental testing stations, as well as in transmission, distribution and laboratory power lines by the Departamento de Materiales of the Instituto de Investigaciones Electricas (IIE). [Espanol] En el presente trabajo se muestra un resumen de los principales factores que originan los problemas de contaminacion en aislamientos. Esto, como resultado de diversos estudios realizados tanto en estaciones de prueba experimentales como en lineas de transmision, distribucion y laboratorio por el Departamento de Materiales del Instituto de Investigaciones Electricas (IIE).

  4. Experimental analysis of the environmental contamination of electrical equipment; Analisis experimental de la contaminacion ambiental en equipos electricos

    Energy Technology Data Exchange (ETDEWEB)

    Campillo Ruiz, Maria Teresa; Ponce Velez, Marco Antonio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1997-12-31

    This paper is a summary of the main causes that originate the contamination problems in insulating materials. This as the result of different studies performed in experimental testing stations, as well as in transmission, distribution and laboratory power lines by the Departamento de Materiales of the Instituto de Investigaciones Electricas (IIE). [Espanol] En el presente trabajo se muestra un resumen de los principales factores que originan los problemas de contaminacion en aislamientos. Esto, como resultado de diversos estudios realizados tanto en estaciones de prueba experimentales como en lineas de transmision, distribucion y laboratorio por el Departamento de Materiales del Instituto de Investigaciones Electricas (IIE).

  5. Selection of distribution coefficients for contaminant fate and transport calculations: Strontium as a case study

    International Nuclear Information System (INIS)

    Kaplan, D.I.; Krupka, K.M.; Serne, R.J.

    1997-01-01

    As part of an ongoing project funded by a cooperative effort involving the Office of Radiation and Indoor Air (ORIA) of the U.S. Environmental Protection Agency (EPA), the Office of Environmental Restoration (EM-40) of the Department of Energy (DOE), and the Nuclear Regulatory Agency (NRC), distribution coefficient (K d ) values are being compiled from the literature to develop provisional tables for cadmium, cesium, chromium, lead, plutonium, strontium, thorium, and uranium. The tables are organized according to important aqueous- and solid-phase parameters affecting the sorption of these contaminants. These parameters, which vary with contaminant, include pH and redox conditions; cation exchange capacity (CEC); presence of iron-oxide, aluminum-oxide, clay, and mica minerals; organic matter content; and solution concentrations of contaminants, competing ions, and complexing ligands. Sorption information compiled for strontium is used to illustrate our approach. The strontium data show how selected geochemical parameters (i.e., CEC, pH, and clay content) affect Strontium K d values and the selection of open-quote default close-quote K d values needed for modeling contaminant transport and risks at sites for which site specific data are lacking. Results of our evaluation may be used by site management and technical staff to assess contaminant fate, migration, and risk calculations in support of site remediation and waste management decisions

  6. Transport of contaminants by Arctic sea ice and surface ocean currents

    International Nuclear Information System (INIS)

    Pfirman, S.

    1995-01-01

    Sea ice and ocean currents transport contaminants in the Arctic from source areas on the shelves, to biologically active regions often more than a thousand kilometers away. Coastal regions along the Siberian margin are polluted by discharges of agricultural, industrial and military wastes in river runoff, from atmospheric deposition and ocean dumping. The Kara Sea is of particular concern because of deliberate dumping of radioactive waste, as well as the large input of polluted river water. Contaminants are incorporated in ice during suspension freezing on the shelves, and by atmospheric deposition during drift. Ice releases its contaminant load through brine drainage, surface runoff of snow and meltwater, and when the floe disintegrates. The marginal ice zone, a region of intense biological activity, may also be the site of major contaminant release. Potentially contaminated ice from the Kara Sea is likely to influence the marginal ice zones of the Barents and Greenland seas. From studies conducted to date it appears that sea ice from the Kara Sea does not typically enter the Beaufort Gyre, and thus is unlikely to affect the northern Canadian and Alaskan margins

  7. Tolerance of negative emotion moderates the amplification of mental contamination following an evoking task: A randomized experimental study.

    Science.gov (United States)

    Fergus, Thomas A

    2018-06-01

    Contamination is a near universal feeling, with mental contamination representing a contamination feeling in the absence of direct physical contact with a source. Extant research indicates that tolerance of negative emotion is important for understanding emotional reactions to images, thoughts, and memories, all of which are common sources of mental contamination. Extending research linking distress tolerance to mental contamination, this study examined if individual differences in the tolerance of negative emotion moderates the amplification of mental contamination following an evoking task. Unselected participants completed a self-report measure of tolerance of negative emotion during an online session. They later attended an in-person session and were randomized to an experimental scenario group: betrayal (n = 49) or control (n = 49). Participants imagined themselves in a scenario, with the betrayal scenario designed to evoke mental contamination. Mental contamination was assessed by self-report before and after the scenario. The betrayal, but not control, scenario caused an increase in mental contamination. Tolerance for negative emotion moderated the effect of group on mental contamination. Group differences in mental contamination evidenced at low, but not high, distress tolerance. A novel experimental manipulation and an unselected sample were used. Future research could assess tolerance of negative emotion using a behavioral task. These results indicate that tolerance of negative emotion may be important for understanding when individuals experience mental contamination. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Characterization of Uranium Contamination, Transport, and Remediation at Rocky Flats - Across Remediation into Post-Closure

    Science.gov (United States)

    Janecky, D. R.; Boylan, J.; Murrell, M. T.

    2009-12-01

    The Rocky Flats Site is a former nuclear weapons production facility approximately 16 miles northwest of Denver, Colorado. Built in 1952 and operated by the Atomic Energy Commission and then Department of Energy, the Site was remediated and closed in 2005, and is currently undergoing long-term surveillance and monitoring by the DOE Office of Legacy Management. Areas of contamination resulted from roughly fifty years of operation. Of greatest interest, surface soils were contaminated with plutonium, americium, and uranium; groundwater was contaminated with chlorinated solvents, uranium, and nitrates; and surface waters, as recipients of runoff and shallow groundwater discharge, have been contaminated by transport from both regimes. A region of economic mineralization that has been referred to as the Colorado Mineral Belt is nearby, and the Schwartzwalder uranium mine is approximately five miles upgradient of the Site. Background uranium concentrations are therefore elevated in many areas. Weapons-related activities included work with enriched and depleted uranium, contributing anthropogenic content to the environment. Using high-resolution isotopic analyses, Site-related contamination can be distinguished from natural uranium in water samples. This has been instrumental in defining remedy components, and long-term monitoring and surveillance strategies. Rocky Flats hydrology interlinks surface waters and shallow groundwater (which is very limited in volume and vertical and horizontal extent). Surface water transport pathways include several streams, constructed ponds, and facility surfaces. Shallow groundwater has no demonstrated connection to deep aquifers, and includes natural preferential pathways resulting primarily from porosity in the Rocky Flats alluvium, weathered bedrock, and discontinuous sandstones. In addition, building footings, drains, trenches, and remedial systems provide pathways for transport at the site. Removal of impermeable surfaces (buildings

  9. Transport Limits for Non-Fixed Contamination: A Hazard to Optimization in Radioprotection

    International Nuclear Information System (INIS)

    Theis, S.; Lorenz, B.; Schwarz, W.

    2004-01-01

    Current contamination limits for packages and conveyances under routine transport conditions have been derived from the Fairbairn model more than 40 years ago. This model has proved to be effective if used with pragmatism, but conservative. In some countries the limits are handled as action levels. Actions are taken if contamination levels are exceeded, but instant reporting to authorities is only necessary if the excess is higher than a certain factor of e.g. 10. In countries like Germany the limits are regarded as strictly binding. As could be seen after contamination incidents with transport casks for spent fuel assembly, the reporting by the media and perception by the public was not in accordance with the real radiation risk, which could in any case be neglected. However, exceeding the limits by only one percent lead in some cases immediately to legal actions. To avoid such actions, any practice with relevance for possible contamination or decontamination must consider an additional safety margin which is usually a factor of 10. This results -by the definition of TS-R1 recommendations- in a complete removal of non fixed contamination. For two examples the tremendous amount of decontamination work as well as measurements, which are necessary to reach this aim, is quantified. The first example focuses on the clearance measurements of 20' standard ISO-containers, (which are used exclusively for the transport of radioactive materials,) as conveyances for shipment of radioactive packages. In the second example (a loaded cask awaiting shipment) such actions lead to a real operational exposure which -according to good health physics practice- should otherwise be subject to minimization. These information is compared with the results of an IAEA working group, which was set up in 2000 with the aim of remodeling the exposure conditions for all persons involved in the transport of radioactive material, even members of the public. This international group combined members

  10. Transport Limits for Non-Fixed Contamination: A Hazard to Optimization in Radioprotection

    Energy Technology Data Exchange (ETDEWEB)

    Theis, S.; Lorenz, B.; Schwarz, W.

    2004-07-01

    Current contamination limits for packages and conveyances under routine transport conditions have been derived from the Fairbairn model more than 40 years ago. This model has proved to be effective if used with pragmatism, but conservative. In some countries the limits are handled as action levels. Actions are taken if contamination levels are exceeded, but instant reporting to authorities is only necessary if the excess is higher than a certain factor of e.g. 10. In countries like Germany the limits are regarded as strictly binding. As could be seen after contamination incidents with transport casks for spent fuel assembly, the reporting by the media and perception by the public was not in accordance with the real radiation risk, which could in any case be neglected. However, exceeding the limits by only one percent lead in some cases immediately to legal actions. To avoid such actions, any practice with relevance for possible contamination or decontamination must consider an additional safety margin which is usually a factor of 10. This results -by the definition of TS-R1 recommendations- in a complete removal of non fixed contamination. For two examples the tremendous amount of decontamination work as well as measurements, which are necessary to reach this aim, is quantified. The first example focuses on the clearance measurements of 20' standard ISO-containers, (which are used exclusively for the transport of radioactive materials,) as conveyances for shipment of radioactive packages. In the second example (a loaded cask awaiting shipment) such actions lead to a real operational exposure which -according to good health physics practice- should otherwise be subject to minimization. These information is compared with the results of an IAEA working group, which was set up in 2000 with the aim of remodeling the exposure conditions for all persons involved in the transport of radioactive material, even members of the public. This international group combined

  11. Computational modeling and experimental characterization of indoor aerosol transport

    International Nuclear Information System (INIS)

    Konecni, Snezana; Whicker, Jeffrey J.; Martin, Richard A.

    2002-01-01

    When a hazardous aerosol or gas is inadvertently or deliberately released in an occupied facility, the airborne material presents a hazard to people. Inadvertent accidents and exposures continue to occur in Los Alamos and other nuclear facilities despite state-of-art engineering and administrative controls, and heightened diligence. Despite the obvious need in occupational settings and for homeland defense, the body of research in hazardous aerosol dispersion and control in large, complex, ventilated enclosures is extremely limited. The science governing generation, transport, inhalation, and detection of airborne hazards is lacking and must be developed to where it can be used by engineers or safety professionals in the prediction of worker exposure, in the prevention of accidents, or in the mitigation of terrorist actions. In this study, a commercial computational fluid dynamics (CFD) code, CFX5.4, and experiments were used to assess flow field characteristics, and to investigate aerosol release and transport in a large, ventilated workroom in a facility at Savannah River Site. Steady state CFD results illustrating a complex, ventilation-induced, flow field with vortices, velocity gradients, and quiet zones are presented, as are time-dependent CFD and experimental aerosol dispersion results. The comparison of response times between CFD and experimental results was favorable. It is believed that future applications of CFD and experiments can have a favorable impact on the design of ventilation (HVAC) systems and worker safety with consideration to facility costs. Ultimately, statistical methods will be used in conjunction with CFD calculations to determine the optimal number and location of detectors, as well as optimal egress routes in event of a release.

  12. Deregulated Renal Calcium and Phosphate Transport during Experimental Kidney Failure.

    Directory of Open Access Journals (Sweden)

    Wilco P Pulskens

    Full Text Available Impaired mineral homeostasis and inflammation are hallmarks of chronic kidney disease (CKD, yet the underlying mechanisms of electrolyte regulation during CKD are still unclear. Here, we applied two different murine models, partial nephrectomy and adenine-enriched dietary intervention, to induce kidney failure and to investigate the subsequent impact on systemic and local renal factors involved in Ca(2+ and Pi regulation. Our results demonstrated that both experimental models induce features of CKD, as reflected by uremia, and elevated renal neutrophil gelatinase-associated lipocalin (NGAL expression. In our model kidney failure was associated with polyuria, hypercalcemia and elevated urinary Ca(2+ excretion. In accordance, CKD augmented systemic PTH and affected the FGF23-αklotho-vitamin-D axis by elevating circulatory FGF23 levels and reducing renal αklotho expression. Interestingly, renal FGF23 expression was also induced by inflammatory stimuli directly. Renal expression of Cyp27b1, but not Cyp24a1, and blood levels of 1,25-dihydroxy vitamin D3 were significantly elevated in both models. Furthermore, kidney failure was characterized by enhanced renal expression of the transient receptor potential cation channel subfamily V member 5 (TRPV5, calbindin-D28k, and sodium-dependent Pi transporter type 2b (NaPi2b, whereas the renal expression of sodium-dependent Pi transporter type 2a (NaPi2a and type 3 (PIT2 were reduced. Together, our data indicates two different models of experimental kidney failure comparably associate with disturbed FGF23-αklotho-vitamin-D signalling and a deregulated electrolyte homeostasis. Moreover, this study identifies local tubular, possibly inflammation- or PTH- and/or FGF23-associated, adaptive mechanisms, impacting on Ca(2+/Pi homeostasis, hence enabling new opportunities to target electrolyte disturbances that emerge as a consequence of CKD development.

  13. Charge Transport in LDPE Nanocomposites Part I—Experimental Approach

    Directory of Open Access Journals (Sweden)

    Anh T. Hoang

    2016-03-01

    Full Text Available This work presents results of bulk conductivity and surface potential decay measurements on low-density polyethylene and its nanocomposites filled with uncoated MgO and Al2O3, with the aim to highlight the effect of the nanofillers on charge transport processes. Material samples at various filler contents, up to 9 wt %, were prepared in the form of thin films. The performed measurements show a significant impact of the nanofillers on reduction of material’s direct current (dc conductivity. The investigations thus focused on the nanocomposites having the lowest dc conductivity. Various mechanisms of charge generation and transport in solids, including space charge limited current, Poole-Frenkel effect and Schottky injection, were utilized for examining the experimental results. The mobilities of charge carriers were deduced from the measured surface potential decay characteristics and were found to be at least two times lower for the nanocomposites. The temperature dependencies of the mobilities were compared for different materials.

  14. Characterization of contaminant transport by gravity, capilliarity and barometric pumping in heterogeneous vadose regimes. 1997 annual progress report

    International Nuclear Information System (INIS)

    Carrigan, C.R.

    1997-01-01

    'Vadose regimes can be the sites of complex interactions between the atmosphere and groundwater. When a volatile contaminant exists as free product or in dissolved form in the vadose environment, upward transport can occur with the contaminant ultimately being vented as a vapor into the atmosphere. This transport happens naturally and can be enhanced by anisotropy resulting from heterogenities in the vadose regime. Several stages in the transport process are involved in going from a volatile, liquid state contaminant to a contaminant vapor vented at the surface. In a three-year effort, called the Vadose Zone Transport Study, the authors are investigating, with the aid of existing data, new field studies involving dissolved tracer gases and 3-D diagnostic computer simulations that provide a framework to interpret the observations, the detailed nature of each of these stages of transport in several different kinds of vadose regimes. They are emphasizing the impact of features specific to a site, that is, the local geology and hydrology, on each stage of the transport process. In particular they want to better understand how the time scales for (1) partitioning contaminants from the liquid to the vapor states and then (2) transporting the vapor out of the vadose regime are dependent on the specific character of a site. Such time-scale information will be important for evaluating the potential of contaminant sources as well as remediation strategies including natural remediation approaches.'

  15. Application of SPARROW modeling to understanding contaminant fate and transport from uplands to streams

    Science.gov (United States)

    Ator, Scott; Garcia, Ana Maria.

    2016-01-01

    Understanding spatial variability in contaminant fate and transport is critical to efficient regional water-quality restoration. An approach to capitalize on previously calibrated spatially referenced regression (SPARROW) models to improve the understanding of contaminant fate and transport was developed and applied to the case of nitrogen in the 166,000 km2 Chesapeake Bay watershed. A continuous function of four hydrogeologic, soil, and other landscape properties significant (α = 0.10) to nitrogen transport from uplands to streams was evaluated and compared among each of the more than 80,000 individual catchments (mean area, 2.1 km2) in the watershed. Budgets (including inputs, losses or net change in storage in uplands and stream corridors, and delivery to tidal waters) were also estimated for nitrogen applied to these catchments from selected upland sources. Most (81%) of such inputs are removed, retained, or otherwise processed in uplands rather than transported to surface waters. Combining SPARROW results with previous budget estimates suggests 55% of this processing is attributable to denitrification, 23% to crop or timber harvest, and 6% to volatilization. Remaining upland inputs represent a net annual increase in landscape storage in soils or biomass exceeding 10 kg per hectare in some areas. Such insights are important for planning watershed restoration and for improving future watershed models.

  16. A generalized model for transport of contaminants in soil by electric fields.

    Science.gov (United States)

    Paz-Garcia, Juan Manuel; Baek, Kitae; Alshawabkeh, Iyad D; Alshawabkeh, Akram N

    2012-01-01

    A generalized model applicable to soils contaminated with multiple species under enhanced boundary conditions during treatment by electric fields is presented. The partial differential equations describing species transport are developed by applying the law of mass conservation to their fluxes. Transport, due to migration, advection and diffusion, of each aqueous component and complex species are combined to produce one partial differential equation that describes transport of the total analytical concentrations of component species which are the primary dependent variables. This transport couples with geochemical reactions such as aqueous equilibrium, sorption, precipitation and dissolution. The enhanced model is used to simulate electrokinetic cleanup of lead and copper contaminants at an Army Firing Range. Acid enhancement is achieved by the use of adipic acid to neutralize the basic front produced for the cathode electrochemical reaction. The model is able to simulate enhanced application of the process by modifying the boundary conditions. The model showed that kinetics of geochemical reactions, such as metals dissolution/leaching and redox reactions, may be significant for realistic prediction of enhanced electrokinetic extraction of metals in real-world applications.

  17. Evaluation of wastewater contaminant transport in surface waters using verified Lagrangian sampling

    Science.gov (United States)

    Antweiler, Ronald C.; Writer, Jeffrey H.; Murphy, Sheila F.

    2014-01-01

    Contaminants released from wastewater treatment plants can persist in surface waters for substantial distances. Much research has gone into evaluating the fate and transport of these contaminants, but this work has often assumed constant flow from wastewater treatment plants. However, effluent discharge commonly varies widely over a 24-hour period, and this variation controls contaminant loading and can profoundly influence interpretations of environmental data. We show that methodologies relying on the normalization of downstream data to conservative elements can give spurious results, and should not be used unless it can be verified that the same parcel of water was sampled. Lagrangian sampling, which in theory samples the same water parcel as it moves downstream (the Lagrangian parcel), links hydrologic and chemical transformation processes so that the in-stream fate of wastewater contaminants can be quantitatively evaluated. However, precise Lagrangian sampling is difficult, and small deviations – such as missing the Lagrangian parcel by less than 1 h – can cause large differences in measured concentrations of all dissolved compounds at downstream sites, leading to erroneous conclusions regarding in-stream processes controlling the fate and transport of wastewater contaminants. Therefore, we have developed a method termed “verified Lagrangian” sampling, which can be used to determine if the Lagrangian parcel was actually sampled, and if it was not, a means for correcting the data to reflect the concentrations which would have been obtained had the Lagrangian parcel been sampled. To apply the method, it is necessary to have concentration data for a number of conservative constituents from the upstream, effluent, and downstream sites, along with upstream and effluent concentrations that are constant over the short-term (typically 2–4 h). These corrections can subsequently be applied to all data, including non-conservative constituents. Finally, we

  18. Evaluation of wastewater contaminant transport in surface waters using verified Lagrangian sampling.

    Science.gov (United States)

    Antweiler, Ronald C; Writer, Jeffrey H; Murphy, Sheila F

    2014-02-01

    Contaminants released from wastewater treatment plants can persist in surface waters for substantial distances. Much research has gone into evaluating the fate and transport of these contaminants, but this work has often assumed constant flow from wastewater treatment plants. However, effluent discharge commonly varies widely over a 24-hour period, and this variation controls contaminant loading and can profoundly influence interpretations of environmental data. We show that methodologies relying on the normalization of downstream data to conservative elements can give spurious results, and should not be used unless it can be verified that the same parcel of water was sampled. Lagrangian sampling, which in theory samples the same water parcel as it moves downstream (the Lagrangian parcel), links hydrologic and chemical transformation processes so that the in-stream fate of wastewater contaminants can be quantitatively evaluated. However, precise Lagrangian sampling is difficult, and small deviations - such as missing the Lagrangian parcel by less than 1h - can cause large differences in measured concentrations of all dissolved compounds at downstream sites, leading to erroneous conclusions regarding in-stream processes controlling the fate and transport of wastewater contaminants. Therefore, we have developed a method termed "verified Lagrangian" sampling, which can be used to determine if the Lagrangian parcel was actually sampled, and if it was not, a means for correcting the data to reflect the concentrations which would have been obtained had the Lagrangian parcel been sampled. To apply the method, it is necessary to have concentration data for a number of conservative constituents from the upstream, effluent, and downstream sites, along with upstream and effluent concentrations that are constant over the short-term (typically 2-4h). These corrections can subsequently be applied to all data, including non-conservative constituents. Finally, we show how data

  19. Experimental study of fast electron transport in dense plasmas

    International Nuclear Information System (INIS)

    Vaisseau, Xavier

    2014-01-01

    The framework of this PhD thesis is the inertial confinement fusion for energy production, in the context of the electron fast ignition scheme. The work consists in a characterization of the transport mechanisms of fast electrons, driven by intense laser pulses (10 19 - 10 20 W/cm 2 ) in both cold-solid and warm-dense matter. The first goal was to study the propagation of a fast electron beam, characterized by a current density ≥ 10 11 A/cm 2 , in aluminum targets initially heated close to the Fermi temperature by a counter-propagative planar shock. The planar compression geometry allowed us to discriminate the energy losses due to the resistive mechanisms from collisional ones by comparing solid and compressed targets of the same initial areal densities. We observed for the first time a significant increase of resistive energy losses in heated aluminum samples. The confrontation of the experimental data with the simulations, including a complete characterization of the electron source, of the target compression and of the fast electron transport, allowed us to study the time-evolution of the material resistivity. The estimated resistive electron stopping power in a warm-compressed target is of the same order as the collisional one. We studied the transport of the fast electrons generated in the interaction of a high-contrast laser pulse with a hollow copper cone, buried into a carbon layer, compressed by a counter-propagative planar shock. A X-ray imaging system allowed us to visualize the coupling of the laser pulse with the cone at different moments of the compression. This diagnostic, giving access to the fast electron spatial distribution, showed a fast electron generation in the entire volume of the cone for late times of compression, after shock breakout from the inner cone tip. For earlier times, the interaction at a high-contrast ensured that the source was contained within the cone tip, and the fast electron beam was collimated into the target depth by

  20. Chaotic-dynamical conceptual model to describe fluid flow and contaminant transport in a fractured vadose zone. 1998 annual progress report

    International Nuclear Information System (INIS)

    Doughty, C.; Dragila, M.I.; Faybishenko, B.; Podgorney, R.K.; Stoops, T.M.; Wheatcraft, S.W.; Wood, T.R.

    1998-01-01

    'DOE faces the remediation of numerous contaminated sites, such as those at Hanford, INEEL, LLNL, and LBNL, where organic and/or radioactive wastes were intentionally or accidentally released to the vadose zone from surface spills, underground tanks, cribs, shallow ponds, and deep wells. Migration of these contaminants through the vadose zone has lead to the contamination of or threatens to contaminate underlying groundwater. A key issue in choosing a corrective action plan to clean up contaminated sites is to determine the location, total mass, mobility and travel time to receptors for contaminants moving in the vadose zone. These problems are difficult to solve in a technically defensible and accurate manner because contaminants travel downward intermittently through narrow pathways driven by variations in environmental conditions. These preferential pathways can be difficult to find and predict. The primary objective of this project is to determine if and when dynamical chaos theory can be used to investigate infiltration of fluid and contaminant transport in heterogeneous soils and fractured rocks. The objective of this project is being achieved through the following Activities (1) Evaluation of chaotic behavior of flow in laboratory and field experiments using methods from non-linear dynamics; (2) Evaluation of the impact these dynamics may have on contaminant transport through heterogeneous fractured rocks and soils, and how it can be used to guide remediation efforts; (3) Development of a conceptual model and mathematical and numerical algorithms for flow and transport, which incorporate both: (a) the spatial variability of heterogeneous porous and fractured media, and (b) the description of the temporal dynamics of flow and transport, which may be chaotic; and (4) Development of appropriate experimental field and laboratory techniques needed to detect diagnostic parameters for chaotic behavior of flow. This approach is based on the assumption that spatial

  1. Experience with contamination protection of spent fuel transport packages in Germany since 2000/2001

    International Nuclear Information System (INIS)

    Krinninger, H.; Bach, R.; Seidel, J.; Jung, P.

    2004-01-01

    On April 30, 1998 just a few days before the PATRAM 1998 conference at Paris, the French Nuclear Installations Safety Directorate (DSIN now DGSNR) published a press release, that during the year before some 35% of the spent fuel transports to the reprocessing plant of COGEMA at La Hague have non-fixed surface contamination in excess of the regulatory standard. A few day in advance DSIN informed in French Ministries and the competent foreign authorities of the customer countries of COGEMA. The consequences of this publication were multi-fold and perceived by the public as an act negligence of the nuclear industry. Because of concerns about additional radiation exposure to the railway workers by the unions the French Railway company SNCF suspended all transports by May 6, 1998 until implementation of corrective measures. This decision of SNF interupted also the spent fuel transports from continental Europe to the reprocessing plant of BNFL at Sellafield all performed across France to the port of Dunkirk. Furthermore on May 25, 1998 the German Federal Ministry of Environment, Nature Protection and Nuclear Safety (BMU) imposed a transport ban for shipment of spent fuel from commercial power plants and for high active waste returned from La Hague to the Gorleben site. The conditions for resumption of these transports were outlined by NMU in a 10-point programme. In response to these publications on contamination findings competent German State and Federal Authorities commissioned investigations by independent experts dealing with the identification of the causes, the proposal of counter measures, the investigation of shortcomings in the transport system in general and recommendations for retification of it

  2. Using Contaminant Transport Modeling to Determine Historical Discharges at the Surface

    Science.gov (United States)

    Fogwell, T. W.

    2013-12-01

    When it is determined that a contaminated site needs to be remediated, the issue of who is going to pay for that remediation is an immediate concern. This means that there needs to be a determination of who the responsible parties are for the existing contamination. Seldom is it the case that records have been made and kept of the surface contaminant discharges. In many cases it is possible to determine the relative amount of contaminant discharge at the surface of the various responsible parties by employing a careful analysis of the history of contaminant transport through the surface, through the vadose zone, and within the saturated zone. The process begins with the development of a dynamic conceptual site model that takes into account the important features of the transport of the contaminants through the vadose zone and in the groundwater. The parameters for this model can be derived from flow data available for the site. The resulting contaminant transport model is a composite of the vadose zone transport model, together with the saturated zone (groundwater) flow model. Any calibration of the model should be carefully employed in order to avoid using information about the conclusions of the relative discharge amounts of the responsible parties in determining the calibrated parameters. Determination of the leading edge of the plume is an important first step. It is associated with the first discharges from the surface of the site. If there were several discharging parties at the same time, then it is important to establish a chemical or isotopic signature of the chemicals that were discharged. The time duration of the first discharger needs to be determined as accurately as possible in order to establish the appropriate characterization of the leading portion of the resulting plume in the groundwater. The information about the first discharger and the resulting part of the plume associated with this discharger serves as a basis for the determination of the

  3. Monte Carlo simulation of nonlinear reactive contaminant transport in unsaturated porous media

    International Nuclear Information System (INIS)

    Giacobbo, F.; Patelli, E.

    2007-01-01

    In the current proposed solutions of radioactive waste repositories, the protective function against the radionuclide water-driven transport back to the biosphere is to be provided by an integrated system of engineered and natural geologic barriers. The occurrence of several nonlinear interactions during the radionuclide migration process may render burdensome the classical analytical-numerical approaches. Moreover, the heterogeneity of the barriers' media forces approximations to the classical analytical-numerical models, thus reducing their fidelity to reality. In an attempt to overcome these difficulties, in the present paper we adopt a Monte Carlo simulation approach, previously developed on the basis of the Kolmogorov-Dmitriev theory of branching stochastic processes. The approach is here extended for describing transport through unsaturated porous media under transient flow conditions and in presence of nonlinear interchange phenomena between the liquid and solid phases. This generalization entails the determination of the functional dependence of the parameters of the proposed transport model from the water content and from the contaminant concentration, which change in space and time during the water infiltration process. The corresponding Monte Carlo simulation approach is verified with respect to a case of nonreactive transport under transient unsaturated flow and to a case of nonlinear reactive transport under stationary saturated flow. Numerical applications regarding linear and nonlinear reactive transport under transient unsaturated flow are reported

  4. Origins and transport of aquatic dioxins in the Japanese watershed: soil contamination, land use, and soil runoff events.

    Science.gov (United States)

    Kanematsu, Masakazu; Shimizu, Yoshihisa; Sato, Keisuke; Kim, Suejin; Suzuki, Tasuma; Park, Baeksoo; Saino, Reiko; Nakamura, Masafumi

    2009-06-15

    Significant dioxins accumulations in Japanese forests and paddy fields have been observed, and surface soil runoff caused by rainfall and irrigation (i.e., soil puddling in paddy fields) results in dioxins input into the aquatic environment. An extensive investigation into the origins and transport of aquatic dioxins in the Yasu watershed, Japan was conducted considering surface soil contamination level, land use, and type of soil runoff event (i.e., irrigation runoff [IR], rainfall runoff [RR], and base flow [BF]). Combined use of the chemically activated luciferase expression (CALUX) assay together with high-resolution gas chromatography and high-resolution mass spectrometry (HRGC/HRMS) efficiently enabled this study, so that origins, transport, and dynamic movement of aquatic dioxins in the watershed were revealed. The particulate organic carbon normalized particulate-dioxins WHO-toxic equivalent (TEQ) concentration predicted by the CALUX assay (Spar) was found to be a convenient molecular marker to indicate origins of aquatic dioxins and clearly reflect surface soil contamination level, land use, and soil runoff events. Using experimental results and theoretical modeling, the annual loading amount of dioxins at the middle reach of the river was estimated to be 0.458 mg WHO-TEQ in 2004. More than 96.6% of the annual loading amount was attributed to RR and derived almost evenly from forest and paddy fields at the study location. Because the annual loading amount at the middle reach is less than 0.5% of the total dioxins accumulated in the upper basin, dioxins runoff from the Japanese watershed will continue. This study shows that the combined use of the bioassay with HRGC/HRMS can provide new insights into dioxins transport and fate in the environment.

  5. Long Length Contaminated Equipment Retrieval System Receiver Trailer and Transport Trailer Operations and Maintenance Manual

    International Nuclear Information System (INIS)

    DALE, R.N.

    2000-01-01

    A system to accommodate the removal of long-length contaminated equipment (LLCE) from Hanford underground radioactive waste storage tanks was designed, procured, and demonstrated, via a project activity during the 1990s. The system is the Long Length Contaminated Equipment Removal System (LLCERS). LLCERS will be maintained and operated by Tank Farms Engineering and Operations organizations and other varied projects having a need for the system. The responsibility for the operation and maintenance of the LLCERS Receiver Trailer (RT) and Transport Trailer (TT) resides with the RPP Characterization Project Operations organization. The purpose of this document is to provide vendor supplied operating and maintenance (O and M) information for the RT and TT in a readily retrievable form. This information is provided this way instead of in a vendor information (VI) file to maintain configuration control of the operations baseline as described in RPP-6085, ''Configuration Management Plan for Long Length Contaminated Equipment Receiver and Transport Trailers''. Additional Operations Baseline documents are identified in RPP-6085

  6. Long Length Contaminated Equipment Retrieval System Receiver Trailer and Transport Trailer Operations and Maintenance Manual

    Energy Technology Data Exchange (ETDEWEB)

    DALE, R.N.

    2000-05-01

    A system to accommodate the removal of long-length contaminated equipment (LLCE) from Hanford underground radioactive waste storage tanks was designed, procured, and demonstrated, via a project activity during the 1990s. The system is the Long Length Contaminated Equipment Removal System (LLCERS). LLCERS will be maintained and operated by Tank Farms Engineering and Operations organizations and other varied projects having a need for the system. The responsibility for the operation and maintenance of the LLCERS Receiver Trailer (RT) and Transport Trailer (TT) resides with the RPP Characterization Project Operations organization. The purpose of this document is to provide vendor supplied operating and maintenance (O & M) information for the RT and TT in a readily retrievable form. This information is provided this way instead of in a vendor information (VI) file to maintain configuration control of the operations baseline as described in RPP-6085, ''Configuration Management Plan for Long Length Contaminated Equipment Receiver and Transport Trailers''. Additional Operations Baseline documents are identified in RPP-6085.

  7. Assessment of Contaminated Brine Fate and Transport in MB139 at WIPP

    Energy Technology Data Exchange (ETDEWEB)

    Kuhlman, Kristopher L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Applied Systems Analysis and Research Dept.; Malama, Bwalya [Sandia National Lab., Carlsbad, NM (United States). Performance Assessment Dept.

    2014-07-01

    Following the radionuclide release event of February 14, 2014 at the Waste Isolation Pilot Plant (WIPP), actinide contamination has been found on the walls and floor in Panel 7 as a result of a release in Room 7 of Panel 7. It has been proposed to decontaminate Panel 7 at the WIPP by washing contaminated surfaces in the underground with fresh water. A cost-effective cleanup of this contamination would allow for a timely return to waste disposal operations at WIPP. It is expected that the fresh water used to decontaminate Panel 7 will flow as contaminated brine down into the porosity of the materials under the floor – the run-of-mine (ROM) salt above Marker Bed 139 (MB139) and MB139 itself – where its fate will be controlled by the hydraulic and transport properties of MB139. Due to the structural dip of MB139, it is unlikely that this brine would migrate northward towards the Waste-Handling Shaft sump. A few strategically placed shallow small-diameter observation boreholes straddling MB139 would allow for monitoring the flow and fate of this brine after decontamination. Additionally, given that flow through the compacted ROM salt floor and in MB139 would occur under unsaturated (or two-phase) conditions, there is a need to measure the unsaturated flow properties of crushed WIPP salt and salt from the disturbed rock zone (DRZ).

  8. Time-lapse electrical resistivity anomalies due to contaminant transport around landfills

    Directory of Open Access Journals (Sweden)

    J. Yang

    2007-06-01

    Full Text Available The extent of landfill leachate can be delineated by geo-electrical imaging as a response to the varying electrical resistivity in the contaminated area. This research was based on a combination of hydrogeological numerical simulation followed by geophysical forward and inversion modeling performed to evaluate the migration of a contaminant plume from a landfill. As a first step, groundwater flow and contaminant transport was simulated using the finite elements numerical modeling software FEFLOW. The extent of the contaminant plume was acquired through a hydrogeological model depicting the distributions of leachate concentration in the system. Next, based on the empirical relationship between the concentration and electrical conductivity of the leachate in the porous media, the corresponding geo-electrical structure was derived from the hydrogeological model. Finally, forward and inversion computations of geo-electrical anomalies were performed using the finite difference numerical modeling software DCIP2D/DCIP3D. The image obtained by geophysical inversion of the electric data was expected to be consistent with the initial hydrogeological model, as described by the distribution of leachate concentration. Numerical case studies were conducted for various geological conditions, hydraulic parameters and electrode arrays, from which conclusions were drawn regarding the suitability of the methodology to assess simple to more complex geo-electrical models. Thus, optimal mapping and monitoring configurations were determined.

  9. Experimental study of particle transport and density fluctuation in LHD

    International Nuclear Information System (INIS)

    Tanaka, K.; Morita, S.; Sanin, A.; Michael, C.; Kawahata, K.; Yamada, H.; Miyazawa, J.; Tokuzawa, T.; Akiyama, T.; Goto, M.; Ida, K.; Yoshinuma, M.; Narihara, K.; Yamada, I.; Yokoyama, M.; Masuzaki, S.; Morisaki, T.; Sakamoto, R.; Funaba, H.; Komori, A.; Vyacheslavov, L.N.; Murakami, S.; Wakasa, A.

    2005-01-01

    A variety of electron density (n e ) profiles have been observed in Large Helical Device (LHD). The density profiles change dramatically with heating power and toroidal magnetic field (B t ) under the same line averaged density. The particle transport coefficients, i.e., diffusion coefficient (D) and convection velocity (V) are experimentally obtained from density modulation experiments in the standard configuration. The values of D and V are estimated separately at the core and edge. The diffusion coefficients are strong function of electron temperature (T e ) and are proportional to T e 1.7±0.9 in core and T e 1.1±0.14 in edge. And edge diffusion coefficients are proportional to B t -2.08 . It is found that the scaling of D in edge is close to gyro-Bohm-like in nature. The existence of non-zero V is observed. It is observed that the electron temperature (T e ) gradient can drive particle convection. This is particularly clear in the core region. The convection velocity in the core region reverses direction from inward to outward as the T e gradient increases. In the edge, the convection is inward directed in the most of the case of the present data set. And it shows modest tendency, whose value is proportional to T e gradient keeping inward direction. However, the toroidal magnetic field also significantly affects value and direction of V. The spectrum of density fluctuation changes at different heating power suggesting that it has an influence on particle transport. The peak wavenumber is around 0.1 times the inversed ion Larmor radius, as is expected from gyro-Bohm diffusion. The peaks of fluctuation intensity are localized at the plasma edge, where density gradient becomes negative and diffusion contributes most to the particle flux. These results suggest a qualitative correlation of fluctuations with particle diffusion. (author)

  10. Experimental study of particle transport and density fluctuation in LHD

    International Nuclear Information System (INIS)

    Tanaka, K.; Michael, C.; Sanin, A.

    2005-01-01

    A variety of electron density (n e ) profiles have been observed in Large Helical Device (LHD). The density profiles change dramatically with heating power and toroidal magnetic field (B t ) under the same line averaged density. The particle transport coefficients, i.e., diffusion coefficient (D) and convection velocity (V) are experimentally obtained in the standard configuration from density modulation experiments. The values of D and V are estimated separately in the core and edge. The diffusion coefficients are found to be a strong function of electron temperature (T e ) and are proportional to T e 1.7±0.9 in the core and T e 1.1±0.14 in the edge. Edge diffusion coefficients are proportional to B t -2.08 . It is found that the scaling of D in the edge is close to gyro-Bohm-like in nature. Non-zero V is observed and it is found that the electron temperature gradient can drive particle convection, particularly in the core region. The convection velocity in the core reverses direction from inward to outward as the T e gradient increases. In the edge, convection is inward directed in most cases of the present data set. It shows a modest tendency, being proportional to T e gradient and remaining inward directed. However, the toroidal magnetic field also significantly affects the value and direction of V. The density fluctuation spectrum varies with heating power suggesting that it has an influence on particle transport. The value of K sub(perpendicular) ρ i is around 0.1, as expected for gyro-Bohm diffusion. Fluctuations are localized in both positive and negative density gradient regions of the hollow density profiles. The fluctuation power in each region is clearly distinguished having different phase velocity profiles. (author)

  11. Transport of short lived radioactive contaminants with prologed half-lives of daughters through river water

    International Nuclear Information System (INIS)

    Metwally, S.M.; Prohl, G.

    2005-01-01

    One of the main pathways for transporting contaminants to other parts in the environment, are rivers. This work is devoted for deriving and assessment the concentration of soluble radio contaminants along a river at any time after discharge, including the short-lived radionuclides in comparison with the discharge time interval, and prolonged half-life of the produced daughter nuclei. The assumed boundary conditions and deduced formulas can be applied either in case of accidental release or discharge under authority control. The formulas determining the produced daughter nuclei concentration require inequality of the parent and daughter nuclei half-lives. Because of the regional variation of river morphology, the assumed constancy of the flow velocity and dispersion coefficient requires dividing the river path into zones of similar hydrologic characteristics

  12. FLAME: A finite element computer code for contaminant transport n variably-saturated media

    International Nuclear Information System (INIS)

    Baca, R.G.; Magnuson, S.O.

    1992-06-01

    A numerical model was developed for use in performance assessment studies at the INEL. The numerical model referred to as the FLAME computer code, is designed to simulate subsurface contaminant transport in a variably-saturated media. The code can be applied to model two-dimensional contaminant transport in an and site vadose zone or in an unconfined aquifer. In addition, the code has the capability to describe transport processes in a porous media with discrete fractures. This report presents the following: description of the conceptual framework and mathematical theory, derivations of the finite element techniques and algorithms, computational examples that illustrate the capability of the code, and input instructions for the general use of the code. The development of the FLAME computer code is aimed at providing environmental scientists at the INEL with a predictive tool for the subsurface water pathway. This numerical model is expected to be widely used in performance assessments for: (1) the Remedial Investigation/Feasibility Study process and (2) compliance studies required by the US Department of energy Order 5820.2A

  13. Development and applications of two finite element groundwater flow and contaminant transport models: FEWA and FEMA

    International Nuclear Information System (INIS)

    Yeh, G.T.; Wong, K.V.; Craig, P.M.; Davis, E.C.

    1985-01-01

    This paper presents the construction, verification, and application of two groundwater flow and contaminant transport models: A Finite Element Model of Water Flow through Aquifers (FEWA) and A Finite Element Model of Material Transport through Aquifers (FEMA). The construction is based on the finite element approximation of partial differential equations of groundwater flow (FEWA) and of solute movement (FEMA). The particular features of FEWA and FEMA are their versatility and flexibility for dealing with nearly all vertically integrated two-dimensional problems. The models were verified against both analytical solutions and widely used US Geological Survey finite difference approximations. They were then applied for calibration and validation, using data obtained in experiments at the Engineering Test Facility at Oak Ridge National Laboratory. Results indicated that the models are valid for this specific site. To demonstrate the versatility anf flexibility of the models, they were applied to two hypothetical, but realistic, complex problems and three field sites across the United States. In these applications the models yielded good agreement with the field data for all three sites. Finally, the predictive capabilities of the models were demonstrated using data obtained at the Hialeah Preston site in Florida. This case illustrates the capability of FEWA and FEMA as predictive tools and their usefulness in the management of groundwater flow and contaminant transport. 25 refs

  14. FLAME: A finite element computer code for contaminant transport n variably-saturated media

    Energy Technology Data Exchange (ETDEWEB)

    Baca, R.G.; Magnuson, S.O.

    1992-06-01

    A numerical model was developed for use in performance assessment studies at the INEL. The numerical model referred to as the FLAME computer code, is designed to simulate subsurface contaminant transport in a variably-saturated media. The code can be applied to model two-dimensional contaminant transport in an and site vadose zone or in an unconfined aquifer. In addition, the code has the capability to describe transport processes in a porous media with discrete fractures. This report presents the following: description of the conceptual framework and mathematical theory, derivations of the finite element techniques and algorithms, computational examples that illustrate the capability of the code, and input instructions for the general use of the code. The development of the FLAME computer code is aimed at providing environmental scientists at the INEL with a predictive tool for the subsurface water pathway. This numerical model is expected to be widely used in performance assessments for: (1) the Remedial Investigation/Feasibility Study process and (2) compliance studies required by the US Department of energy Order 5820.2A.

  15. Reactive dispersive contaminant transport in coastal aquifers: Numerical simulation of a reactive Henry problem

    KAUST Repository

    Nick, H.M.

    2013-02-01

    The reactive mixing between seawater and terrestrial water in coastal aquifers influences the water quality of submarine groundwater discharge. While these waters come into contact at the seawater groundwater interface by density driven flow, their chemical components dilute and react through dispersion. A larger interface and wider mixing zone may provide favorable conditions for the natural attenuation of contaminant plumes. It has been claimed that the extent of this mixing is controlled by both, porous media properties and flow conditions. In this study, the interplay between dispersion and reactive processes in coastal aquifers is investigated by means of numerical experiments. Particularly, the impact of dispersion coefficients, the velocity field induced by density driven flow and chemical component reactivities on reactive transport in such aquifers is studied. To do this, a hybrid finite-element finite-volume method and a reactive simulator are coupled, and model accuracy and applicability are assessed. A simple redox reaction is considered to describe the degradation of a contaminant which requires mixing of the contaminated groundwater and the seawater containing the terminal electron acceptor. The resulting degradation is observed for different scenarios considering different magnitudes of dispersion and chemical reactivity. Three reactive transport regimes are found: reaction controlled, reaction-dispersion controlled and dispersion controlled. Computational results suggest that the chemical components\\' reactivity as well as dispersion coefficients play a significant role on controlling reactive mixing zones and extent of contaminant removal in coastal aquifers. Further, our results confirm that the dilution index is a better alternative to the second central spatial moment of a plume to describe the mixing of reactive solutes in coastal aquifers. © 2012 Elsevier B.V.

  16. Experimental Study of Airborne Contaminant Migration in an Aircraft Cabin Model

    Science.gov (United States)

    Poussou, Stephane; Sojka, Paul; Plesniak, Michael

    2007-11-01

    The cabin air ventilation system in wide body jetliners is designed to provide a comfortable and controlled environment for passengers. Inside the cabin, the air flows continuously from overhead vents into sidewall exhausts, forming a circular pattern designed to minimize cross flow between adjacent seat rows. However, spreading of gaseous or particulate contaminants is possible when flight attendants or passengers walk along an aisle, perturbing the ventilation flow. Such unsteady flow perturbations have been found to alter the cabin air distribution and quality. A better fundamental understanding of the turbulent transport phenomena is needed to improve air quality monitoring and control systems and to validate numerical simulations. The velocity field in a 15:1 model of a simplified aircraft cabin is probed to investigate the wake of a rectangular body moving through a steady two-dimensional flow at a Reynolds number (based on body height) of the order of 50,000. Planar Laser Induced Fluorescence is used to visualize wake structure and scalar contaminant transport. The interaction between the wake and the ventilation flow is measured with PIV. The data are compared to numerical studies of cabin airflows in the literature.

  17. Experimental Evaluation of Actinide Transport in a Fractured Granodiorite

    Energy Technology Data Exchange (ETDEWEB)

    Dittrich, Timothy M. [Los Alamos National Laboratory; Reimus, Paul W. [Los Alamos National Laboratory

    2015-03-16

    The objective of this study was to demonstrate and evaluate new experimental methods for quantifying the potential for actinide transport in deep fractured crystalline rock formations. We selected a fractured granodiorite at the Grimsel Test Site (GTS) in Switzerland as a model system because field experiments have already been conducted with uranium and additional field experiments using other actinides are planned at the site. Thus, working on this system provides a unique opportunity to compare lab experiment results with fieldscale observations. Rock cores drilled from the GTS were shipped to Los Alamos National Laboratory, characterized by x-ray diffraction and microscopy, and used in batch sorption and column breakthrough experiments. Solutions with pH 6.8 and 8.8 were tested. Solutions were switched to radionuclide-free synthetic Grimsel groundwater after near-steady actinide/colloid breakthrough occurred in column experiments. We are currently evaluating actinide adsorption/desorption rates as a function of water chemistry (initial focus on pH), with future testing planned to evaluate the influence of carbonate concentrations, flow rates, and mineralogy in solutions and suspensions with bentonite colloids. (auth)

  18. Experimental study of tungsten transport properties in T-10 plasma

    Science.gov (United States)

    Krupin, V. A.; Nurgaliev, M. R.; Klyuchnikov, L. A.; Nemets, A. R.; Zemtsov, I. A.; Dnestrovskij, A. Yu.; Sarychev, D. V.; Lisitsa, V. S.; Shurygin, V. A.; Leontiev, D. S.; Borschegovskij, A. A.; Grashin, S. A.; Ryjakov, D. V.; Sergeev, D. S.; Mustafin, N. A.; Trukhin, V. M.; Solomatin, R. Yu.; Tugarinov, S. N.; Naumenko, N. N.

    2017-06-01

    First experimental results of tungsten transport investigation in OH and ECRH plasmas in the T-10 tokamak with W-limiter and movable Li-limiter are presented. It is shown that tungsten tends to accumulate (a joint process of cumulation and peaking) near the plasma axis in ohmic regimes. The cumulation of W is enhanced in discharges with high values of the parameter γ ={{\\bar{n}}\\text{e}}\\centerdot {{\\bar{Z}}\\text{eff}}\\centerdot I\\text{pl}-1.5 that coincides with accumulation conditions of light and medium impurities in T-10 plasmas. Experiments with Li-limiter show the immeasurable level of Li3+ (0.3-0.5% of n e) of T-10 CXRS diagnostics because of the low inflow of Li with respect to other light impurities. Nevertheless, the strong influence of lithium on inflow of light and tungsten impurities is observed. In discharges with lithized walls, vanishing of light impurities occurs and values of {{Z}\\text{eff}}≈ 1 are obtained. It is also shown that the tungsten density in the plasma center decreases by 15 to 20 times while the W inflow reduces only by 2 to 4 times. In lithized discharges with high γ, the flattening of the tungsten density profile occurs and its central concentration decreases up to 10 times during the on-axis ECRH. This effect is observed together with the increase of the W inflow by 3 to 4 times at the ECRH stage.

  19. Generalizing Source Geometry of Site Contamination by Simulating and Analyzing Analytical Solution of Three-Dimensional Solute Transport Model

    Directory of Open Access Journals (Sweden)

    Xingwei Wang

    2014-01-01

    Full Text Available Due to the uneven distribution of pollutions and blur edge of pollutant area, there will exist uncertainty of source term shape in advective-diffusion equation model of contaminant transport. How to generalize those irregular source terms and deal with those uncertainties is very critical but rarely studied in previous research. In this study, the fate and transport of contaminant from rectangular and elliptic source geometry were simulated based on a three-dimensional analytical solute transport model, and the source geometry generalization guideline was developed by comparing the migration of contaminant. The result indicated that the variation of source area size had no effect on pollution plume migration when the plume migrated as far as five times of source side length. The migration of pollution plume became slower with the increase of aquifer thickness. The contaminant concentration was decreasing with scale factor rising, and the differences among various scale factors became smaller with the distance to field increasing.

  20. Development of one-dimensional computational fluid dynamics code 'GFLOW' for groundwater flow and contaminant transport analysis

    International Nuclear Information System (INIS)

    Rahatgaonkar, P. S.; Datta, D.; Malhotra, P. K.; Ghadge, S. G.

    2012-01-01

    Prediction of groundwater movement and contaminant transport in soil is an important problem in many branches of science and engineering. This includes groundwater hydrology, environmental engineering, soil science, agricultural engineering and also nuclear engineering. Specifically, in nuclear engineering it is applicable in the design of spent fuel storage pools and waste management sites in the nuclear power plants. Ground water modeling involves the simulation of flow and contaminant transport by groundwater flow. In the context of contaminated soil and groundwater system, numerical simulations are typically used to demonstrate compliance with regulatory standard. A one-dimensional Computational Fluid Dynamics code GFLOW had been developed based on the Finite Difference Method for simulating groundwater flow and contaminant transport through saturated and unsaturated soil. The code is validated with the analytical model and the benchmarking cases available in the literature. (authors)

  1. FACT (Version 2.0) - Subsurface Flow and Contaminant Transport Documentation and User's Guide

    Energy Technology Data Exchange (ETDEWEB)

    Aleman, S.E.

    2000-05-05

    This report documents a finite element code designed to model subsurface flow and contaminant transport, named FACT. FACT is a transient three-dimensional, finite element code designed to simulate isothermal groundwater flow, moisture movement, and solute transport in variably saturated and fully saturated subsurface porous media.

  2. Experimental Study and Reactive Transport Modeling of Boric Acid Leaching of Concrete

    Directory of Open Access Journals (Sweden)

    Chiang K.-T. K.

    2013-07-01

    Full Text Available Borated water leakage through spent fuel pools (SFPs at pressurized water reactors is a concern because it could cause corrosion of reinforcement steel in the concrete structure, compromise the integrity of the structure, or cause unmonitored releases of contaminated water to the environment. Experimental data indicate that pH is a critical parameter that determines the corrosion susceptibility of rebar in borated water and the degree of concrete degradation by boric acid leaching. In this study, reactive transport modeling of concrete leaching by borated water was performed to provide information on the solution pH in the concrete crack or matrix and the degree of concrete degradation at different locations of an SFP concrete structure exposed to borated water. Simulations up to 100 years were performed using different boric acid concentrations, crack apertures, and solution flow rates. Concrete cylinders were immersed in boric acid solutions for several months and the mineralogical changes and boric acid penetration in the concrete cylinder were evaluated as a function of time. The depths of concrete leaching by boric acid solution derived from the reactive transport simulations were compared with the measured boric acid penetration depth.

  3. Subsurface Flow and Contaminant Transport Documentation and User's Guide

    Energy Technology Data Exchange (ETDEWEB)

    Aleman, S.E.

    1999-07-28

    This report documents a finite element code designed to model subsurface flow and contaminant transport, named FACT. FACT is a transient three-dimensional, finite element code designed to simulate isothermal groundwater flow, moisture movement, and solute transport in variably saturated and fully saturated subsurface porous media. The code is designed specifically to handle complex multi-layer and/or heterogeneous aquifer systems in an efficient manner and accommodates a wide range of boundary conditions. Additionally, 1-D and 2-D (in Cartesian coordinates) problems are handled in FACT by simply limiting the number of elements in a particular direction(s) to one. The governing equations in FACT are formulated only in Cartesian coordinates.

  4. Real time simulation of the release and transport of radioactive contaminants

    International Nuclear Information System (INIS)

    Popa, F.; Weber, M.

    1991-01-01

    Calculating the responses of the radiation monitoring system (RMS) remains one of the most difficult aspects of nuclear power plant simulation to bring into the post-TMI, first principles simulator era. This task requires the simulation of the transport of radioactive contaminants, the transport of the radiation itself, and the instrument channel including the detector. The complex physics and lack of knowledge of input parameters have made these models lag the general simulator trend away from logical/heuristic modeling of physical systems. This paper describes a series of advances to the modeling methodology to change this situation. The objective in the design of this real time simulation model was to always calculate qualitatively reasonable radiation detector readings

  5. Experimental analysis on removal factor of smear method in measurement of surface contamination

    International Nuclear Information System (INIS)

    Sugiura, Nobuyuki; Taira, Junichi; Takenaka, Keisuke; Yamanaka, Kazuo; Sugai, Kenji; Kosako, Toshiso

    2007-01-01

    The smear test is one of the important ways to measure surface contamination. The loose contamination under the high background radiation, which is more significant in handling non-sealed radioisotopes, can be evaluated by this method. The removal factor is defined as the ratio of the activity removed from the surface by one smear to the whole activity of the removable surface contamination. The removal factor is greatly changed by the quality and condition of surface materials. In this study, the values of removal factor at several typical surface conditions were evaluated experimentally and the practical application of those values was considered. It is required the smear should be pressed by moderate pressure when wiping the surface. The pressure from 1.0 kg to 1.5 kg per filter paper was recommended. The removal factor showed lower value in wiping by the pressure below 1.0 kg. The value of 0.5 for the removal factor could be applied to the smooth surface of linoleum, concrete coated with paint or epoxy resin, stainless steel and glass with the statistical allowance. (author)

  6. Microbiological quality control of single-walled carbon-nanotubes-coated surfaces experimentally contaminated

    International Nuclear Information System (INIS)

    Natalizi, T.; Frioni, A.; Passeri, D.; Pantanella, F.

    2013-01-01

    The emergence of new nanotechnologies involves the spreading of nanoparticles in various fields of human life. Nanoparticles in general and, more specifically, carbon nanotubes have been adopted for many practical approaches i.e.: coatings for medical devices, food process industry and drug delivery. Humans will be increasingly exposed to nanoparticles but the susceptibility of nanostructured materials to microbial colonization in process of manufacturing and storage has not been thoroughly considered. Therefore, the microbiological quality control of nanoparticles plays a pivotal role. Different analytical methods have been attempted for detecting bacterial population contaminating a surface, but no one can be considered fully appropriate. Here, BioTimer Assay (BTA) and conventional sonication followed by colony forming units method (S-CFU) were applied for microbiological quality control of single-walled carbon nanotubes (SWCNTs)-coated surfaces experimentally contaminated with Streptococcus mutans and Pseudomonas aeruginosa. Our results demonstrated that S-CFU is unreliable to actually determine the number of bacteria, contaminating abiotic surfaces, as it does not detach all adherent bacteria and kills part of the bacterial population. Instead, BTA is a reliable method to enumerate bacteria colonizing SWCNTs-coated surfaces and can be considered a useful tool for microbiological quality control of nanomaterials for human use.

  7. Experimental investigation of focusing and transport of heavy-current electron beams

    International Nuclear Information System (INIS)

    Baranchikov, E.I.; Gordeev, A.V.; Koba, Yu.V.; Korolev, V.D.; Pen'kina, V.S.; Rudakov, L.I.; Smirnov, V.P.; Sukhov, A.D.; Tarumov, E.Z.

    The results of an experimental and theoretical study of beam transfer through transverse magnetic fields are outlined. The injection and transport of an annular relativistic electron beam due to a magnetic trap of acute-angle geometry are experimentally studied

  8. A reactive transport model for mercury fate in contaminated soil--sensitivity analysis.

    Science.gov (United States)

    Leterme, Bertrand; Jacques, Diederik

    2015-11-01

    We present a sensitivity analysis of a reactive transport model of mercury (Hg) fate in contaminated soil systems. The one-dimensional model, presented in Leterme et al. (2014), couples water flow in variably saturated conditions with Hg physico-chemical reactions. The sensitivity of Hg leaching and volatilisation to parameter uncertainty is examined using the elementary effect method. A test case is built using a hypothetical 1-m depth sandy soil and a 50-year time series of daily precipitation and evapotranspiration. Hg anthropogenic contamination is simulated in the topsoil by separately considering three different sources: cinnabar, non-aqueous phase liquid and aqueous mercuric chloride. The model sensitivity to a set of 13 input parameters is assessed, using three different model outputs (volatilized Hg, leached Hg, Hg still present in the contaminated soil horizon). Results show that dissolved organic matter (DOM) concentration in soil solution and the binding constant to DOM thiol groups are critical parameters, as well as parameters related to Hg sorption to humic and fulvic acids in solid organic matter. Initial Hg concentration is also identified as a sensitive parameter. The sensitivity analysis also brings out non-monotonic model behaviour for certain parameters.

  9. A Review of Removable Surface Contamination on Radioactive Materials Transportation Containers

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, Jr, W. E.; Watson, E. C.; Murphy, D. W.; Harrer, B. J.; Harty, R.; Aldrich, J. M.

    1981-05-01

    This report contains the results of a study sponsored by the U.S. Nuclear Regulatory Commission (NRC) of removable surface contamination on radioactive materials transportation containers. The purpose of the study is to provide information to the NRC during their review of existing regulations. Data was obtained from both industry and literature on three major topics: 1) radiation doses, 2) economic costs, and 3) contamination frequencies. Containers for four categories of radioactive materials are considered including radiopharmaceuticals, industrial sources, nuclear fuel cycle materials, and low-level radioactive waste. Assumptions made in this study use current information to obtain realistic yet conservative estimates of radiation dose and economic costs. Collective and individual radiation doses are presented for each container category on a per container basis. Total doses, to workers and the public, are also presented for spent fuel cask and low-level waste drum decontamination. Estimates of the additional economic costs incurred by lowering current limits by factors of 10 and 100 are presented. Current contamination levels for each category of container are estimated from the data collected. The information contained in this report is designed to be useful to the NRC in preparing their recommendations for new regulations.

  10. Transport of contaminants from energy-process-waste leachates through subsurface soils and soil components: laboratory experiments

    International Nuclear Information System (INIS)

    Wangen, L.E.; Stallings, E.A.; Walker, R.D.

    1982-08-01

    The subsurface transport and attenuation of inorganic contaminants common to a variety of energy process waste leachates are being studied using laboratory column methods. Anionic species currently being emphasized are As, B, Mo, and Se. Transport of the cations Cd and Ni is also being studied. The solid adsorbents consist of three soil mineral components (silica sand, kaolinite, and goethite), and four subsurface soils (a dunal sand, an oxidic sandy clay loam, an acidic clay loam, and an alkaline clay loam). Breakthrough patterns of these species from packed soil columns are followed by monitoring eluent concentrations vs time under carefully controlled laboratory conditions. This report describes the experimental methods being used, the results of preliminary batch adsorption studies, and the results of column experiments completed through calendar year 1981. Using column influent concentrations of about 10 mg/l, adsorption (mmoles/100 g) has been determined from the eluent volume corresponding to 50% breakthrough. On silica sand, kaolinite, dunal sand, and goethite, respectively, these are 2.0 x 10 -4 , 0.020, 0.013, and 0.31 for cadmium, 4.4 x 10 -4 , 0.039, 0.020, and 0.98 for nickel. On kaolinite, dunal sand, and goethite, respectively, adsorption values (mmoles/100 g) are As (0.24, 0.019, and 20.5), B (0.041, 0.0019, and 1.77), Mo (0.048, 0.0010, and 5.93), and Se (0.029, 0.00048, and 1.30). Arsenic is the most highly adsorbed contaminant species and goethite has the largest adsorption capacity of the adsorbents

  11. Method of processing dismantled products of radiation-contaminated equipments and transportation container therefor

    International Nuclear Information System (INIS)

    Komura, Shiro; Heki, Hideaki.

    1991-01-01

    In a method of decontaminating dismantled products of radiation-contaminated equipments removed at nuclear power facilities and classifying the dismantled products depending on their remaining radioactivity levels measured at a processing facility, the dismantled products are contained in a transportation container, to which decontamination liquids are injected and they are transferred to the processing facility. The decontaminated liquid wastes are drained from the transportation container, the dismantled products are washed while being contained in the transportation container as they are. Then, they are transferred to a step for measuring their remaining radioactivity level. This can shorten the time from the containment of the dismantled products to the transportation container to the completion of the decontamination, to improve the efficiency for the decontamination processing. Further, by separately containing the dismantled products on every kind of materials to respective containers, the processing time can be appropriately controlled respectively even if the dissolving efficiency to the decontamination liquids is different depending on the materials. (T.M.)

  12. Transport of Aquatic Contaminant and Assessment of Radioecological Exposure with Spatial and Temporal Effects

    Science.gov (United States)

    Feng, Ying

    1995-01-01

    A comprehensive study of the radioecological exposure assessment for a contaminated aquatic ecosystem has been performed in this dissertation. The primary objectives of this research were to advance the understanding of radiation exposure in nature and to increase current capabilities for estimating aquatic radiation exposure with the consideration of spatial and temporal effect in nature. This was accomplished through the development of a two-dimensional aquatic exposure assessment framework and by applying the framework to the contaminated Chernobyl cooling lake (pond). This framework integrated spatial and temporal heterogeneity effects of contaminant concentration, abundance and distribution of ecosystem populations, spatial- and temporal-dependent (or density-dependent) radionuclide ingestion, and alternative food web structures. The exposure model was built on the population level to allow for the integration of density dependent population regulation into the exposure assessment. Plankton population dynamics have been integrated into the hydrodynamic-transport model to determine plankton biomass density changes and distributions. The distribution of contaminant in water was also calculated using a hydrodynamic-transport model. The significance of adding spatial and temporal effects, spatial and temporal related ecological functions, and hydrodynamics in the exposure assessment was illustrated through a series of case studies. The results suggested that the spatial and temporal heterogeneity effects of radioactive environments were substantial. Among the ecological functions considered, the food web structure was the most important contributor to the variations of fish exposure. The results obtained using a multiple prey food web structure differed by a factor of 20 from the equilibrium concentration, and by a factor of 2.5 from the concentration obtained using a single-prey food web. Impacts of changes in abundance and distribution of biomass on contaminant

  13. The use of tracer techniques in the study of soil water flows and contaminant transport

    International Nuclear Information System (INIS)

    Reeves, A.D.; Beven, K.J.

    1990-04-01

    This report reviews the use of different types of tracers in the characterisation of soil water flows and the implications of tracer studies for modelling contaminant transport. The tracers considered are a number of different anions, stable isotopes, radioactive tracers, organic dyes, fluorocarbons, gases, solid particles and water temperature. The theoretical basis for modelling the results of tracer experiments in terms of the traditional convective-dispersion equation (CDE) is outlined. A number of alternative modelling strategies are reviewed: the mobile/immobile water extension of the CDE; the Jury Transfer Function Model (TFM); the Aggregated Mixing Zone (AMZ) model and Random Particle Tracking models. The first will form the basis of the Systeme Hydrologique Europeen (SHE) contaminant transport component. The Jury and AMZ models are both linear models and are consequently limited to applications in which the flows may be considered to be quasi-steady or repeatable. Random particle tracking models have the advantage of both flexibility and applicability to transient and spatially variable flow domains. A random particle model is being implemented on a transputer workstation at Lancaster and will be used to explore the effect of sub-grid scale complexities on effective grid-scale parameter values for distributed models such as SHE. (author)

  14. Campylobacter genotypes from poultry transportation crates indicate a source of contamination and transmission.

    Science.gov (United States)

    Hastings, R; Colles, F M; McCarthy, N D; Maiden, M C J; Sheppard, S K

    2011-01-01

    Crates used to transport live poultry can be contaminated with Campylobacter, despite periodic sanitization, and are potential vectors for transmission between flocks. We investigated the microbial contamination of standard and silver ion containing crates in normal use and the genetic structure of associated Campylobacter populations. Bacteria from crates were enumerated by appropriate culture techniques, and multilocus sequence typing (MLST) was used to determine the genetic structure of Campylobacters isolated from standard and silver ion containing crates. Compared to standard crates, counts of bacteria, including Campylobacter, were consistently lower on silver ion containing crates throughout the decontamination process. In total, 16 different sequence types were identified from 89 Campylobacter jejuni isolates from crates. These were attributed to putative source population (chicken, cattle, sheep, the environment, wild bird) using the population genetic model, structure. Most (89%) were attributed to chicken, with 22% attribution to live chicken and 78% to retail poultry meat. MLST revealed a progressive shift in allele frequencies through the crate decontamination process. Campylobacter on crates survived for at least 3 h after sanitization, a period of time equivalent to the journey from the processing plant to the majority of farms in the catchment, showing the potential for involvement of crates in transmission. Inclusion of a silver ion biocide in poultry transportation crates to levels demonstrating acceptable antibacterial activity in vitro reduces the level of bacterial contamination during normal crate use compared to standard crates. Molecular analysis of Campylobacter isolates indicated a change in genetic structure of the population with respect to the poultry-processing plant sanitization practice. The application of a sustainable antimicrobial to components of poultry processing may contribute to reducing the levels of Campylobacter

  15. Surfactant-enhanced flushing enhances colloid transport and alters macroporosity in diesel-contaminated soil.

    Science.gov (United States)

    Guan, Zhuo; Tang, Xiang-Yu; Nishimura, Taku; Katou, Hidetaka; Liu, Hui-Yun; Qing, Jing

    2018-02-01

    Soil contamination by diesel has been often reported as a result of accidental spillage, leakage and inappropriate use. Surfactant-enhanced soil flushing is a common remediation technique for soils contaminated by hydrophobic organic chemicals. In this study, soil flushing with linear alkylbenzene sulfonates (LAS, an anionic surfactant) was conducted for intact columns (15cm in diameter and 12cm in length) of diesel-contaminated farmland purple soil aged for one year in the field. Dynamics of colloid concentration in column outflow during flushing, diesel removal rate and resulting soil macroporosity change by flushing were analyzed. Removal rate of n-alkanes (representing the diesel) varied with the depth of the topsoil in the range of 14%-96% while the n-alkanes present at low concentrations in the subsoil were completely removed by LAS-enhanced flushing. Much higher colloid concentrations and larger colloid sizes were observed during LAS flushing in column outflow compared to water flushing. The X-ray micro-computed tomography analysis of flushed and unflushed soil cores showed that the proportion of fine macropores (30-250μm in diameter) was reduced significantly by LAS flushing treatment. This phenomenon can be attributed to enhanced clogging of fine macropores by colloids which exhibited higher concentration due to better dispersion by LAS. It can be inferred from this study that the application of LAS-enhanced flushing technique in the purple soil region should be cautious regarding the possibility of rapid colloid-associated contaminant transport via preferential pathways in the subsurface and the clogging of water-conducting soil pores. Copyright © 2017. Published by Elsevier B.V.

  16. Studies Related to the Role of Colloids on the Transport of Some Radio Contaminants in Groundwater

    International Nuclear Information System (INIS)

    Mekhemar, H.S.A.

    2012-01-01

    The safety of a radioactive waste repository is related to its capacity to confine radioactivity and isolate it from biosphere. The most likely process that can lead to the release of radionuclides from a repository to the geosphere is transport by groundwater. The transport and distribution of radionuclides in groundwater or through geologic media depend on the radioactive source, the physicochemical forms of radionuclides and interactions of radionuclides with other components present in the groundwater. Colloids naturally exist in groundwater aquifers and can significantly impact contaminant migration rate. The presence of colloids affects contaminant transport in aquifers either by facilitation or retardation. The effect of the presence of colloid (Al 2 O 3 ) on the sorption characteristics of Co 2+ and Cs + , as two of the most important radionuclides commonly encountered in the Egyptian waste streams, onto yellow sand and clay taken from Inshas site was studied. Based on the obtained results, the maximum sorption capacity of Cs + and Co 2+ in presence of colloid was higher than sorption in absence of colloid but the sorption capacity of clay was found to be greater than that of yellow sand for both ions in absence and presence of colloid. Sorption capacity (q) increased by increasing initial metal ion concentration. The increasing temperature from 25 to 65 degree C leads to slight decrease in the sorption of Cs ions while lead to increase in sorption of Co ions. The kinetic data could be successfully interpreted by simplified second order kinetic expression. The rate constants and the theoretical equilibrium Sorption capacities were calculated for studied cases. It was demonstrated from column experiments that colloid presence influences radionuclides transport through fixed bed yellow sand column. Al 2 O 3 and Fe 2 O 3 colloids reduce the migration of Cs + and Co 2+ ions in all studied cases. From the results of desorption experiments it can be concluded

  17. Improving estimates of subsurface gas transport in unsaturated fractured media using experimental Xe diffusion data and numerical methods

    Science.gov (United States)

    Ortiz, J. P.; Ortega, A. D.; Harp, D. R.; Boukhalfa, H.; Stauffer, P. H.

    2017-12-01

    Gas transport in unsaturated fractured media plays an important role in a variety of applications, including detection of underground nuclear explosions, transport from volatile contaminant plumes, shallow CO2 leakage from carbon sequestration sites, and methane leaks from hydraulic fracturing operations. Gas breakthrough times are highly sensitive to uncertainties associated with a variety of hydrogeologic parameters, including: rock type, fracture aperture, matrix permeability, porosity, and saturation. Furthermore, a couple simplifying assumptions are typically employed when representing fracture flow and transport. Aqueous phase transport is typically considered insignificant compared to gas phase transport in unsaturated fracture flow regimes, and an assumption of instantaneous dissolution/volatilization of radionuclide gas is commonly used to reduce computational expense. We conduct this research using a twofold approach that combines laboratory gas experimentation and numerical modeling to verify and refine these simplifying assumptions in our current models of gas transport. Using a gas diffusion cell, we are able to measure air pressure transmission through fractured tuff core samples while also measuring Xe gas breakthrough measured using a mass spectrometer. We can thus create synthetic barometric fluctuations akin to those observed in field tests and measure the associated gas flow through the fracture and matrix pore space for varying degrees of fluid saturation. We then attempt to reproduce the experimental results using numerical models in PLFOTRAN and FEHM codes to better understand the importance of different parameters and assumptions on gas transport. Our numerical approaches represent both single-phase gas flow with immobile water, as well as full multi-phase transport in order to test the validity of assuming immobile pore water. Our approaches also include the ability to simulate the reaction equilibrium kinetics of dissolution

  18. Experimental investigation of concentration and stable isotopes signals during organic contaminants back diffusion

    DEFF Research Database (Denmark)

    Jin, Biao; Nika, Chrysanthi-Elisabeth; Rolle, Massimo

    2017-01-01

    -dichloroethene (cis-DCE) as model contaminant and we investigated its back diffusion from an impermeable source into a permeable saturated layer, in which advection-dominated flow conditions were established. We used concentration and stable chlorine isotope measurements to investigate the plumes originated by cis...... and stable isotope gradients in the flow-through setup. In particular, steep concentration and stable isotope gradients were observed at the outlet. Lateral isotope gradients corresponding to chlorine isotope fractionation up to 20‰ were induced by cis-DCE back diffusion and subsequent advection......-dominated transport in all flow-through experiments. A numerical modeling approach, tracking individually all chlorine isotopologues, based on the accurate parameterization of local dispersion, as well as on the values of aqueous diffusion coefficients and diffusion-induced isotope fractionation from a previous study...

  19. The Effects of Subsurface Bioremediation on Soil Structure, Colloid Formation, and Contaminant Transport

    Science.gov (United States)

    Wang, Y.; Liang, X.; Zhuang, J.; Radosevich, M.

    2016-12-01

    Anaerobic bioremediation is widely applied to create anaerobic subsurface conditions designed to stimulate microorganisms that degrade organic contaminants and immobilize toxic metals in situ. Anaerobic conditions that accompany such techniques also promotes microbially mediated Fe(III)-oxide mineral reduction. The reduction of Fe(III) could potentially cause soil structure breakdown, formation of clay colloids, and alternation of soil surface chemical properties. These processes could then affect bioremediation and the migration of contaminants. Column experiments were conducted to investigate the impact of anaerobic bioreduction on soil structure, hydraulic properties, colloid formation, and transport of three tracers (bromide, DFBA, and silica shelled silver nanoparticles). Columns packed with inoculated water stable soil aggregates were placed in anaerobic glovebox, and artificial groundwater media was pumped into the columns to simulate anaerobic bioreduction process for four weeks. Decent amount of soluble Fe(II) accompanied by colloids were detected in the effluent from bioreduction columns a week after initiation of bioreduction treatment, which demonstrated bioreduction of Fe(III) and formation of colloids. Transport experiments were performed in the columns before and after bioreduction process to assess the changes of hydraulic and surface chemical properties through bioreduction treatment. Earlier breakthrough of bromide and DFBA after treatment indicated alterations in flow paths (formation of preferential flow paths). Less dispersion of bromide and DFBA, and less tailing of DFBA after treatment implied breakdown of soil aggregates. Dramatically enhanced transport and early breakthrough of silica shelled silver nanoparticles after treatment supported the above conclusion of alterations in flow paths, and indicated changes of soil surface chemical properties.

  20. Determination of correlation and scaling factors of radionuclides in the contaminated soils from experimental lysimetric field

    International Nuclear Information System (INIS)

    Dulanska, S.

    2009-04-01

    Correlation and regression analyses are often confused in evaluations of experimental results. However, the correlation analysis describes the influence of one variable level changes to changes of the other variable levels and holds for the variables measured quantitatively. It detects the existence and nature of dependencies, measures the goodness-of-fit of an actual model and tests the hypotheses of statistical significance of the model proposed. The y variable does not depend on the x variable but two random variables, x and y, vary jointly. The regression model, however, takes the independent variable x as a non-random variable and the dependent variable y as a random one, in contrast to the correlation model. There are a number of common difficulties associated with real datasets. The first involves the detection and elimination of outliers in the original data. We think of data as being divided into two classes (1) good observations (the majority of data) reflecting population scatter of data and (2) the outliers (if any) being a part of the so-called influential fatal points or noise. The goal of any outlier detection is to find this true partition and, thus, separate good from outlying observations. Regression diagnostics represent procedures for an examination of the regression triplet (data, model, method) for identification of (a) the data quality for a proposed model; (b) the model quality for a given set of data; (c) a fulfillment of all least-squares assumptions. Scheme and statistical evaluation of suitable scaling models for the monitoring of observed radionuclides 241 Am, 238 Pu and 239 , 240 Pu in real contaminated soils of experimental lysimetric field on the basis of experimental results were the objectives. Suitable scaling models for 241 Am, 238 Pu and 239 , 240 Pu radionuclide monitoring in contaminated soil samples placed in an experimental lysimeter have been proven by a regression triplet analysis. Estimates of and parameters for all

  1. Experimental challenges to stiffness as a transport paradigm

    Science.gov (United States)

    Luce, T. C.; Burrell, K. H.; Holland, C.; Marinoni, A.; Petty, C. C.; Smith, S. P.; Austin, M. E.; Grierson, B. A.; Zeng, L.

    2018-02-01

    Two power scans were carried out in H-mode plasmas in DIII-D; one employed standard co-current neutral beam injection (NBI), while the other used a mixture of co-current and counter-current NBI to scan power while holding the torque to a low fixed value. Analysis of the ion and electron heat transport, ion toroidal angular momentum transport, and thermal deuterium transport from these scans is presented. Invariance of the gradients or gradient scalelengths, as might be expected from stiff transport, was not generally observed. When invariance was seen, it was not accompanied by a strong increase in transport, except in the case of the absolute deuterium ion transport. Conduction in the ion channel is the dominant energy loss mechanism. The variation of the ion heat transport with applied power is similar for the co-injection and fixed torque scans, indicating that E  ×  B shearing is not determining the plasma response to additional power. There is however, a quantitative difference in the transport between the two scans, indicating E  ×  B shearing does play a role in the transport. Comparison of these results with a previous experiment that directly probed stiffness at a single radius leads to the following conclusion: while local stiffness as formally defined may hold, invariance of the gradients or normalized scalelengths does not follow from stiff transport in more practical scaling experiments, such as the power scans discussed here. Possible reasons for the lack of correspondence between the local picture and the global expectations are discussed.

  2. Understanding transport pathways in a river system - Monitoring sediments contaminated by an incident

    Science.gov (United States)

    Dietrich, S.; Kleisinger, C.; Hillebrand, G.; Claus, E.; Schwartz, R.; Carls, I.; Winterscheid, A.; Schubert, B.

    2016-12-01

    Experiments to trace transport of sediments and suspended particulate matter on a river scale are an expensive and difficult venture, since it causes a lot of official requirements. In spring 2015, polychlorinated biphenyls (PCB) were released during restoration works at a bridge in the upper part of the Elbe River, near the Czech-German border. In this study, the particle-bound PCB-transport is applied as a tracer for monitoring transport pathways of suspended solids (SS) along a whole river stretch over 700 km length. The incident was monitored by concentration measurements of seven indicator PCB congeners along the inland part of the Elbe River as well as in the Elbe estuary. Data from 15 monitoring stations (settling tanks) as well as from two longitudinal campaigns (grab samples) along the river in July and August 2015 are considered. The total PCB load is calculated for all stations on the basis of monthly contaminant concentrations and daily suspended sediment concentrations. Monte-Carlo simulations assess the uncertainties of the calculated load. 1D water levels and GIS analysis were used to locate temporal storage areas for the SS. It is shown that the ratio of high versus low chlorinated PCB congeners is a suitable tracer to distinguish the PCB load of the incident from the long-term background signal. Furthermore, the reduction of total PCB load within the upper Elbe indicates that roughly 24% of the SS were transported with the water by wash load. Approximately 600 km downstream of the incident site, the PCB-marked wash load was first identified in July 2015. PCB load transported intermittently in suspension was detected roughly 400 km downstream of the incident site by August 2015. In the Elbe Estuary, PCB-marked SS were only found upstream of the steep slope of water depth (approx. 4 to 15 m) within Hamburg harbor that acts as a major sediment sink. Here, SS from the inland Elbe are mixed with lowly contaminated marine material, which may mask the

  3. Montmorillonite dissolution kinetics: Experimental and reactive transport modeling interpretation

    Science.gov (United States)

    Cappelli, Chiara; Yokoyama, Shingo; Cama, Jordi; Huertas, F. Javier

    2018-04-01

    The dissolution kinetics of K-montmorillonite was studied at 25 °C, acidic pH (2-4) and 0.01 M ionic strength by means of well-mixed flow-through experiments. The variations of Si, Al and Mg over time resulted in high releases of Si and Mg and Al deficit, which yielded long periods of incongruent dissolution before reaching stoichiometric steady state. This behavior was caused by simultaneous dissolution of nanoparticles and cation exchange between the interlayer K and released Ca, Mg and Al and H. Since Si was only involved in the dissolution reaction, it was used to calculate steady-state dissolution rates, RSi, over a wide solution saturation state (ΔGr ranged from -5 to -40 kcal mol-1). The effects of pH and the degree of undersaturation (ΔGr) on the K-montmorillonite dissolution rate were determined using RSi. Employing dissolution rates farthest from equilibrium, the catalytic pH effect on the K-montmorillonite dissolution rate was expressed as Rdiss = k·aH0.56±0.05 whereas using all dissolution rates, the ΔGr effect was expressed as a non-linear f(ΔGr) function Rdiss = k · [1 - exp(-3.8 × 10-4 · (|ΔGr|/RT)2.13)] The functionality of this expression is similar to the equations reported for dissolution of Na-montmorillonite at pH 3 and 50 °C (Metz, 2001) and Na-K-Ca-montmorillonite at pH 9 and 80 °C (Cama et al., 2000; Marty et al., 2011), which lends support to the use of a single f(ΔGr) term to calculate the rate over the pH range 0-14. Thus, we propose a rate law that also accounts for the effect of pOH and temperature by using the pOH-rate dependence and the apparent activation energy proposed by Rozalén et al. (2008) and Amram and Ganor (2005), respectively, and normalizing the dissolution rate constant with the edge surface area of the K-montmorillonite. 1D reactive transport simulations of the experimental data were performed using the Crunchflow code (Steefel et al., 2015) to quantitatively interpret the evolution of the released cations

  4. Toward a better understanding of the complex geochemical processes governing subsurface contaminant transport

    International Nuclear Information System (INIS)

    Puls, R.W.

    1990-01-01

    Identification and understanding of the geochemical processes, including ion exchange, precipitation, organic partitioning, chemisorption, aqueous complexation, and colloidal stability and transport, controlling subsurface contamination is essential for making accurate predictions of the fate and transport of these constituents. Current approaches to quantify the effect of these processes primarily involve laboratory techniques, including the use of closed static systems (batch experiments) where small amounts of aquifer solids or minerals are contacted with an aqueous phase containing the components of interest for relatively short durations; and dynamic systems (column experiments) where a larger segment of the aquifer is investigated by analyzing the breakthrough profiles of reactive and non-reactive species. Both approaches are constrained by differences in scale, alteration of media during sample collection and use, and spatial variability. More field reactivity studies are needed to complement established laboratory approaches for the determination of retardation factors and scaling factors, corroboration of batch and column results, and validation of sampling techniques. These studies also serve to accentuate areas of geochemical process research where data deficiencies exist, such as the kinetics of adsorption-desorption, metal-organic-mineral interactions, and colloidal mobility. The advantages and disadvantages of the above approaches are discussed in the context of achieving a more completely integrated approach to geochemical transport experiments, with supportive data presented from selected studies. (Author) (16 refs., 4 figs., 2 tabs.)

  5. Characterization of contaminant transport by gravity, capillarity and barometric pumping in heterogeneous vadose regimes. 1998 annual progress report

    International Nuclear Information System (INIS)

    Carrigan, C.R.; Hudson, G.B.

    1998-01-01

    'The intent of this research program is to obtain an improved understanding of vadose zone transport processes and to develop field and modeling techniques required to characterize contaminant transport in the unsaturated zone at DOE sites. For surface spills and near-surface leaks of chemicals, the vadose zone may well become a long-term source of contamination for the underlying water table. Transport of contaminants can occur in both the liquid and gas phases of the unsaturated zone. This transport occurs naturally as a result of diffusion, buoyancy forces (gravity), capillarity and barometric pressure variations. In some cases transport can be enhanced by anisotropies present in hydrologic regimes. This is particularly true for gas-phase transport which may be subject to vertical pumping resulting from atmospheric pressure changes. For liquid-phase flows, heterogeneity may enhance the downward transport of contaminants to the water table depending on soil properties and the scale of the surface spill or near-surface leak. Characterization techniques based upon the dynamics of transport processes are likely to yield a better understanding of the potential for contaminant transport at a specific site than methods depending solely on hydrologic properties derived from a borehole. Such dynamic-characterization techniques can be useful for evaluating sites where contamination presently exists as well as for providing an objective basis to evaluate the efficacy of proposed as well as implemented clean-up technologies. The real-time monitoring of processes that may occur during clean-up of tank waste and the mobility of contaminants beneath the Hanford storage tanks during sluicing operations is one example of how techniques developed in this effort can be applied to current remediation problems. In the future, such dynamic-characterization methods might also be used as part of the site-characterization process for determining suitable locations of new DOE facilities

  6. Accumulation and transport of microbial-size particles in a pressure protected model burn unit: CFD simulations and experimental evidence

    Directory of Open Access Journals (Sweden)

    Mimoun Maurice

    2011-03-01

    Full Text Available Abstract Background Controlling airborne contamination is of major importance in burn units because of the high susceptibility of burned patients to infections and the unique environmental conditions that can accentuate the infection risk. In particular the required elevated temperatures in the patient room can create thermal convection flows which can transport airborne contaminates throughout the unit. In order to estimate this risk and optimize the design of an intensive care room intended to host severely burned patients, we have relied on a computational fluid dynamic methodology (CFD. Methods The study was carried out in 4 steps: i patient room design, ii CFD simulations of patient room design to model air flows throughout the patient room, adjacent anterooms and the corridor, iii construction of a prototype room and subsequent experimental studies to characterize its performance iv qualitative comparison of the tendencies between CFD prediction and experimental results. The Electricité De France (EDF open-source software Code_Saturne® (http://www.code-saturne.org was used and CFD simulations were conducted with an hexahedral mesh containing about 300 000 computational cells. The computational domain included the treatment room and two anterooms including equipment, staff and patient. Experiments with inert aerosol particles followed by time-resolved particle counting were conducted in the prototype room for comparison with the CFD observations. Results We found that thermal convection can create contaminated zones near the ceiling of the room, which can subsequently lead to contaminate transfer in adjacent rooms. Experimental confirmation of these phenomena agreed well with CFD predictions and showed that particles greater than one micron (i.e. bacterial or fungal spore sizes can be influenced by these thermally induced flows. When the temperature difference between rooms was 7°C, a significant contamination transfer was observed to

  7. Simulation of contaminant transport in fractured porous media on triangular meshes

    KAUST Repository

    Dong, Chen

    2010-12-01

    A mathematical model for contaminant species passing through fractured porous media is presented. In the numerical model, we combine two locally conservative methods, i.e. mixed finite element (MFE) and the finite volume (FV) methods. Adaptive triangle mesh is used for effective treatment of the fractures. A hybrid MFE method is employed to provide an accurate approximation of velocities field for both the fractures and matrix which are crucial to the convection part of the transport equation. The FV method and the standard MFE method are used to approximate the convection and dispersion terms respectively. Numerical examples in a medium containing fracture network illustrate the robustness and efficiency of the proposed numerical model. © 2010 IEEE.

  8. Savannah River Laboratory DOSTOMAN code: a compartmental pathways computer model of contaminant transport

    International Nuclear Information System (INIS)

    King, C.M.; Wilhite, E.L.; Root, R.W. Jr.

    1985-01-01

    The Savannah River Laboratory DOSTOMAN code has been used since 1978 for environmental pathway analysis of potential migration of radionuclides and hazardous chemicals. The DOSTOMAN work is reviewed including a summary of historical use of compartmental models, the mathematical basis for the DOSTOMAN code, examples of exact analytical solutions for simple matrices, methods for numerical solution of complex matrices, and mathematical validation/calibration of the SRL code. The review includes the methodology for application to nuclear and hazardous chemical waste disposal, examples of use of the model in contaminant transport and pathway analysis, a user's guide for computer implementation, peer review of the code, and use of DOSTOMAN at other Department of Energy sites. 22 refs., 3 figs

  9. Vadose Zone Contaminant Fate and Transport Analysis for the 216-B-26 Trench

    Energy Technology Data Exchange (ETDEWEB)

    Ward, Andy L.; Gee, Glendon W.; Zhang, Z. F.; Keller, Jason M.

    2004-10-14

    The BC Cribs and Trenches, part of the 200 TW 1 OU waste sites, received about 30 Mgal of scavenged tank waste, with possibly the largest inventory of 99Tc ever disposed to the soil at Hanford and site remediation is being accelerated. The purpose of this work was to develop a conceptual model for contaminant fate and transport at the 216-B-26 Trench site to support identification and development and evaluation of remediation alternatives. Large concentrations of 99Tc high above the water table implicated stratigraphy in the control of the downward migration. The current conceptual model accounts for small-scale stratigraphy; site-specific changes soil properties; tilted layers; and lateral spreading. It assumes the layers are spatially continuous causing water and solutes to move laterally across the boundary if conditions permit. Water influx at the surface is assumed to be steady. Model parameters were generated with pedotransfer functions; these were coupled high resolution neutron moisture logs that provided information on the underlying heterogeneity on a scale of 3 inches. Two approaches were used to evaluate the impact of remedial options on transport. In the first, a 1-D convolution solution to the convective-dispersive equation was used, assuming steady flow. This model was used to predict future movement of the existing plume using the mean and depth dependent moisture content. In the second approach, the STOMP model was used to first predict the current plume distribution followed by its future migration. Redistribution of the 99Tc plume was simulated for the no-action alternative and on-site capping. Hypothetical caps limiting recharge to 1.0, 0.5, and 0.1 mm yr-1 were considered and assumed not to degrade in the long term. Results show that arrival time of the MCLs, the peak arrival time, and the arrival time of the center of mass increased with decreasing recharge rate. The 1-D convolution model is easy to apply and can easily accommodate initial

  10. Simulation of contaminant transport in fractured porous media on triangular meshes

    KAUST Repository

    Dong, Chen; Sun, Shuyu

    2010-01-01

    A mathematical model for contaminant species passing through fractured porous media is presented. In the numerical model, we combine two locally conservative methods, i.e. mixed finite element (MFE) and the finite volume (FV) methods. Adaptive triangle mesh is used for effective treatment of the fractures. A hybrid MFE method is employed to provide an accurate approximation of velocities field for both the fractures and matrix which are crucial to the convection part of the transport equation. The FV method and the standard MFE method are used to approximate the convection and dispersion terms respectively. Numerical examples in a medium containing fracture network illustrate the robustness and efficiency of the proposed numerical model. © 2010 IEEE.

  11. Monitoring Potential Transport of Radioactive Contaminants in Shallow Ephemeral Channels: FY2017

    Energy Technology Data Exchange (ETDEWEB)

    Mizell, Steve A. [Desert Research Inst. (DRI), Las Vegas, NV (United States); Campbell, Scott A. [Desert Research Inst. (DRI), Las Vegas, NV (United States); McCurdy, Greg [Desert Research Inst. (DRI), Las Vegas, NV (United States); Miller, Julianne J. [Desert Research Inst. (DRI), Las Vegas, NV (United States)

    2018-04-01

    The Desert Research Institute (DRI) is conducting a field assessment of the potential for contaminated soil to be transported from the Smoky Site Contamination Area (CA) as a result of storm runoff. This activity supports U.S. Department of Energy (DOE) Environmental Management Nevada Program (EM-NV) efforts to establish post-closure monitoring plans for the Smoky Site Soils Corrective Action Unit (CAU) 550. The work is intended to confirm the likely mechanism of transport and determine the meteorological conditions that might cause the movement of contaminated soils, as well as determine the particle size fraction that is most closely associated with transported radionuclide-contaminated soils. These data will facilitate the design of the appropriate post-closure monitoring program. In 2011, DRI installed a meteorological monitoring station on the west side of the Smoky Site CA and a hydrologic (runoff) monitoring station within the CA, near the east side. Air temperature, wind speed, wind direction, relative humidity, precipitation, solar radiation, barometric pressure, soil temperature, and soil water content are collected at the meteorological station. The maximum, minimum, and average or total values (as appropriate) for each of these parameters are recorded for each 10-minute interval. The maximum, minimum, and average water depth in the flume installed at the hydrology station are also recorded for every 10-minute interval. This report presents data collected from these stations during fiscal year (FY) 2017. During the FY2017 reporting period, the warmest months were June, July, and August and the coldest were December and January. Solar radiation showed the same seasonal trend, although the months with the most solar radiation were May and June. Monthly mean wind speeds were highest in the spring (April and May). Winds were generally from the southwest during the summer and from the northwest throughout the remainder of the year. The monthly average

  12. Use of Short Chained Alkylphenols (SCAP in Analysis of Transport Behaviour of Oil Contaminated Groundwater

    Directory of Open Access Journals (Sweden)

    M. Sauter

    2002-06-01

    Full Text Available Shortchained alkylphenols (SCAP represent a main constituent of crude oil and coal liquefaction products. Due to their specific oil/water partitioning behaviour and high aqueous solubility they can be detected in oil exploitation waters and groundwaters affected by various spills near oil pipelines, oil exploitation sites and coal liquefaction plants. New efficient and powerful analytical techniques have been developed that allow the identification of all 34 individual compounds (C0-C3 without derivatisation and in complex matrices. Due to the different physico-chemical properties of the SCAP, differential transport behaviour in groundwater can be observed, changing the relative concentrations of SCAP downgradient in space and time. These characteristic ratios can be employed to derive information on migration direction and the ageing of the source of contamination. A case study is presented to illustrate the use of this new tool.

  13. Stubborn contaminants: influence of detergents on the purity of the multidrug ABC transporter BmrA.

    Science.gov (United States)

    Wiseman, Benjamin; Kilburg, Arnaud; Chaptal, Vincent; Reyes-Mejia, Gina Catalina; Sarwan, Jonathan; Falson, Pierre; Jault, Jean-Michel

    2014-01-01

    Despite the growing interest in membrane proteins, their crystallization remains a major challenge. In the course of a crystallographic study on the multidrug ATP-binding cassette transporter BmrA, mass spectral analyses on samples purified with six selected detergents revealed unexpected protein contamination visible for the most part on overloaded SDS-PAGE. A major contamination from the outer membrane protein OmpF was detected in purifications with Foscholine 12 (FC12) but not with Lauryldimethylamine-N-oxide (LDAO) or any of the maltose-based detergents. Consequently, in the FC12 purified BmrA, OmpF easily crystallized over BmrA in a new space group, and whose structure is reported here. We therefore devised an optimized protocol to eliminate OmpF during the FC12 purification of BmrA. On the other hand, an additional band visible at ∼110 kDa was detected in all samples purified with the maltose-based detergents. It contained AcrB that crystallized over BmrA despite its trace amounts. Highly pure BmrA preparations could be obtained using either a ΔacrAB E. coli strain and n-dodecyl-β-D-maltopyranoside, or a classical E. coli strain and lauryl maltose neopentyl glycol for the overexpression and purification, respectively. Overall our results urge to incorporate a proteomics-based purity analysis into quality control checks prior to commencing crystallization assays of membrane proteins that are notoriously arduous to crystallize. Moreover, the strategies developed here to selectively eliminate obstinate contaminants should be applicable to the purification of other membrane proteins overexpressed in E. coli.

  14. Stubborn contaminants: influence of detergents on the purity of the multidrug ABC transporter BmrA.

    Directory of Open Access Journals (Sweden)

    Benjamin Wiseman

    Full Text Available Despite the growing interest in membrane proteins, their crystallization remains a major challenge. In the course of a crystallographic study on the multidrug ATP-binding cassette transporter BmrA, mass spectral analyses on samples purified with six selected detergents revealed unexpected protein contamination visible for the most part on overloaded SDS-PAGE. A major contamination from the outer membrane protein OmpF was detected in purifications with Foscholine 12 (FC12 but not with Lauryldimethylamine-N-oxide (LDAO or any of the maltose-based detergents. Consequently, in the FC12 purified BmrA, OmpF easily crystallized over BmrA in a new space group, and whose structure is reported here. We therefore devised an optimized protocol to eliminate OmpF during the FC12 purification of BmrA. On the other hand, an additional band visible at ∼110 kDa was detected in all samples purified with the maltose-based detergents. It contained AcrB that crystallized over BmrA despite its trace amounts. Highly pure BmrA preparations could be obtained using either a ΔacrAB E. coli strain and n-dodecyl-β-D-maltopyranoside, or a classical E. coli strain and lauryl maltose neopentyl glycol for the overexpression and purification, respectively. Overall our results urge to incorporate a proteomics-based purity analysis into quality control checks prior to commencing crystallization assays of membrane proteins that are notoriously arduous to crystallize. Moreover, the strategies developed here to selectively eliminate obstinate contaminants should be applicable to the purification of other membrane proteins overexpressed in E. coli.

  15. Precipitation of metals in produced water : influence on contaminant transport and toxicity

    International Nuclear Information System (INIS)

    Azetsu-Scott, K.; Wohlgeschaffen, G.; Yeats, P.; Dalziel, J.; Niven, S.; Lee, K.

    2006-01-01

    Produced water contains a number of compounds of environmental concern and is the largest volume waste stream from oil and gas production activities. Recent studies have shown that chemicals dissolved in waste water from oil platforms stunted the growth of North Sea cod and affected their breeding patterns. Scientific research is needed to identify the impact of produced water discharges on the environment as well as to identify acceptable disposal limits for produced water. This presentation provided details of a study to characterize produced water discharged within the Atlantic regions of Canada. The study included dose response biological effect studies; research on processes controlling the transport and transformation of contaminants associated with produced water discharges and the development of risk assessment models. The sample location for the study was a site near Sable Island off the coast of Nova Scotia. Chemical analysis of the produced water was conducted as well as toxicity tests. Other tests included a time-series particulate matter sedimentation test; time-series metal and toxicity analysis; time-series change in metal precipitates tests and a produced water/seawater layering experiment. Dissolved and particulate fractions were presented, and the relationship between toxicity and particulate concentrations was examined. Results of the study suggested that produced water contaminants are variable over spatial and temporal scales due to source variations and changes in discharge rates. Chemical changes occur within 24 hours of produced water being mixed with seawater and facilitate contaminant partitioning between the surface micro layer, water column and sediments. Changes in the toxicity of the produced water are correlated with the partitioning of chemical components. The impact zone may be influenced by chemical kinetics that control the distribution of potential toxic metals. Further research is needed to investigate the effects of low level

  16. Direct uptake of cobalt 60 by the carp (Cyprinus carpio L.) following experimental chronic or cyclical contamination of water

    International Nuclear Information System (INIS)

    Amiard-Triquet, C.; Foulquier, L.

    1978-01-01

    Irrespective of the nature of experimental cobalt 60 contamination (chronic or cyclical), the activity level in the carp was highest after 32 or 35 days when the concentration factor reached 3. An analysis of cobalt 60 distribution shows preferential uptake by the kidneys. It therefore seems unlikely that the discharge rate of effluents from the nuclear industry and the resulting variations of radioactivity levels in the water significantly modify the impact of contamination on aquatic organisms [fr

  17. Source identification of hydrocarbon contaminants and their transportation over the Zonguldak shelf, Turkish Black Sea

    Science.gov (United States)

    Unlu, S.; Alpar, B.

    2009-04-01

    Under great anthropogenic pressure due to the substantial freshwater input from the surrounding industrial and agricultural areas, especially central and middle-Eastern Europe, the Black Sea basin is ranked among the most ecologically threatened water bodies of the world. Oil levels are unacceptable in many coastal areas perilously close to polluted harbors and many river mouths; the places presenting the highest levels of bio-diversity and having a high socio-economic importance due to human use of coastal resources. There are about sixty sources of pollution which resulted in "hot spots" having disastrous impacts on sensitive marine and coastal areas and needing immediate priorities for action. Beyond such land-based sources, trans-boundary pollution sources from Black Sea riparian countries, heavy maritime traffic, particularly involving petroleum transports and fishing boats, and the improper disposal of ballast and bilge waters and solid waste are also important marine sources of pollution. Found in fossil fuels such as Polycyclic Aromatic Hydrocarbons are generated by incomplete combustion of organic matter. In order to estimate their distribution in sediment and their sources, they were monitored from the bottom samples offshore the Zonguldak industry region, one of the most polluted spots in the Turkish Black Sea. There the budget of pollutants via rivers is not precisely known due to an evident lack of data on chemical and granulometric composition of the river runoff and their fluxes. Therefore the marine sediments, essential components of marine ecosystems, are very important in our estimating the degree of the damage given to the ecosystem by such inputs. Realization of the sources and transport of these contaminants will be a critical tool for future management of the Zonguldak industry region and its watershed. The sea bottom in study area is composed of mainly sand and silt mixtures with small amount of clay. Geochemical analyses have shown that oil

  18. Application of multiple tracers (SF6 and chloride) to identify the transport by characteristics of contaminant at two separate contaminated sites

    Science.gov (United States)

    Lee, K. K.; Lee, S. S.; Kim, H. H.; Koh, E. H.; Kim, M. O.; Lee, K.; Kim, H. J.

    2016-12-01

    Multiple tracers were applied for source and pathway detection at two different sites. CO2 gas injected in the subsurface for a shallow-depth CO2 injection and leak test can be regarded as a potential contaminant source. Therefore, it is necessary to identify the migration pattern of CO2 gas. Also, at a DNAPL contaminated site, it is important to figure out the characteristics of plume evolution from the source zone. In this study, multiple tracers (SF6 and chloride) were used to evaluate the applicability of volatile and non-volatile tracers and to identify the characteristics of contaminant transport at each CO2 injection and leak test site and DNAPL contaminated site. Firstly, at the CO2 test site, multiple tracers were used to perform the single well push-drift-pull tracer test at total 3 specific depth zones. As results of tests, volatile and non-volatile tracers showed different mass recovery percentage. Most of chloride mass was recovered but less than half of SF6 mass was recovered due to volatile property. This means that only gaseous SF6 leak out to unsaturated zone. However, breakthrough curves of both tracers indicated similar peak time, effective porosity, and regional groundwater velocity. Also, at both contaminated sites, natural gradient tracer tests were performed with multiple tracers. With the results of natural gradient tracer test, it was possible to confirm the applicability of multiple tracers and to understand the contaminant transport in highly heterogeneous aquifer systems through the long-term monitoring of tracers. Acknowledgement: financial support was provided by the R&D Project on Environmental Management of Geologic CO2 Storage)" from the KEITI (Project Number: 2014001810003) and Korea Ministry of Environment as "The GAIA project (2014000540010)".

  19. Surface contamination of spent fuel convoys - resumption of transport in France

    International Nuclear Information System (INIS)

    Pertuis, V.

    2000-01-01

    In France, 1998 was marked by the transport of spent fuel from EDF plants being suspended and then resumed. From the time the first inspections were carried out by the Nuclear Installations Safety Directorate (NISD), in charge of monitoring radioactive and fissile material for civil use since June 1997, surface contamination was found in a high percentage of packages and/or wagons containing spent fuel. The different expert appraisals showed that this had no consequences for the health of the public or of workers. Aiming at the resumption of transport, EDF and Cogema presented to the safety authority a plan of action including an increase in monitoring (number of points and cross-checking by SGS Qualitest), more widespread observance of good practices resulting from analyses by EDF and conclusions of its nuclear inspectorate, and an improvement in radiological cleanliness in the area where casks were loaded. During the inspections carried out at EDF plants, the NISD verified the application of this plan. Several observations were, nevertheless, made regarding maintenance of equipment, failure to apply procedures on a corporate level and the traceability of certain operations. The measures taken to sufficiently inform the public were applied. The NISD is continuing its monitoring actions to ensure that all EDF plants adopt best practices. However, the overall clean-up of EDF plants is a long-term operation. Finally, the NISD is continuing its monitoring of the different stages of spent fuel transport as well as other types of transport of radioactive materials associated with nuclear activities. (author)

  20. 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

  1. 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.

  2. The effects of a perturbed source on contaminant transport near the Weldon Spring quarry

    International Nuclear Information System (INIS)

    Tomasko, D.

    1989-03-01

    The effects of a perturbed contamination source at the Weldon Spring quarry in St. Charles County, Missouri, on downstream solute concentrations were investigated using one-dimensional analytical solutions to an advection-dispersion equation developed for both constant-strength and multiple-stepped source functions. A sensitivity study using parameter base-case values and ranges consistent with the geologic conceptualization of the quarry area indicates that the parameters having the greatest effect on predicted concentrations are the distance from the quarry to the point of interest, the average linear groundwater velocity, the contaminant retardation coefficient, and the amplitude and duration of the source perturbation caused by response action activities. Use of base-case parameter value and realistic values for the amplitude and duration of the source perturbation produced a small effect on solute concentrations near the western extremity of the nearby municipal well field, as well as small uncertainties in the predicted results for the assumed model. The effect of simplifying assumptions made in deriving the analytic solution is unknown: use of a multidimensional flow and transport model and additional field work are needed to validate the model. 13 refs., 18 figs

  3. Transport and deposition of plutonium-contaminated sediments by fluvial processes, Los Alamos Canyon, New Mexico

    International Nuclear Information System (INIS)

    Graf, W.L.

    1996-01-01

    Between 1945 and 1952 the development of nuclear weapons at Los Alamos National Laboratory, New Mexico, resulted in the disposal of plutonium into the alluvium of nearby Acid and (to a lesser degree) DP Canyons. The purpose of this paper is to explore the connection between the disposal sites and the main river, a 20 km link formed by the fluvial system of Acid, Pueblo, DP, and Los Alamos Canyons. Empirical data from 15 yr of annual sediment sampling throughout the canyon system has produced 458 observations of plutonium concentration in fluvial sediments. These data show that, overall, mean plutonium concentrations in fluvial sediment decline from 10,000 fCi/g near the disposal area to 100 fCi/g at the confluence of the canyon system and the Rio Grande. Simulations using a computer model for water, sediment, and plutonium routing in the canyon system show that discharges as large as the 25 yr event would fail to develop enough transport capacity to completely remove the contaminated sediments from Pueblo Canyon. Lesser flows would move some materials to the Rio Grande by remobilization of stored sediments. The simulations also show that the deposits and their contaminants have a predictable geography because they occur where stream power is low, hydraulic resistance is high, and the geologic and/or geomorphic conditions provide enough space for storage. 38 refs., 13 figs., 1 tab

  4. Atmospheric transport of contaminants to remote arctic wilderness areas: A pilot study

    International Nuclear Information System (INIS)

    Crayton, W.M.; Talbot, S.

    1993-01-01

    The Alaska Maritime National Wildlife Refuge includes the Tuxedni Wilderness Area (WA), which is required to meet the Class 1 air quality requirements of the Clean Air Act (42 CFT 7401 et seq.). The Act specifically protects such areas from significant deterioration; however, most Class 1 Wilderness monitoring focuses on visual impairment and traditional atmospheric pollutants such as NOx. This study was designed to assess the feasibility of also measuring atmospheric transport of potentially toxic elemental and organic contaminants to remote areas as a pilot for subsequent monitoring of Service lands to be undertaken through the Biomonitoring of Environmental Status and Trends (BEST) Program. Located on the western shore of Cook Inlet, the Tuxedni WA lies about 80 km downwind of a major petroleum complex that the City of Anchorage. Elemental contaminants emanating from the city will be studied in two species of widely distributed alpine vegetation (Cladina rangiferina, a lichen; and Hylocomium splendens, a moss) collected from elevated windward slopes on Chisik Island, a remote site in the WA. Vegetation samples will be analyzed for a suite of potentially toxic elements by inductively coupled plasma emission spectrometry and atomic absorption spectrophotometry. Polycyclic aromatic compounds originating from petroleum-related and urban sources will be studied through the deployment of lipid-containing passive accumulators and analysis by gas chromatography with photoionization detection. Reference areas will also be selected and monitored

  5. UNCERT: geostatistics, uncertainty analysis and visualization software applied to groundwater flow and contaminant transport modeling

    International Nuclear Information System (INIS)

    Wingle, W.L.; Poeter, E.P.; McKenna, S.A.

    1999-01-01

    UNCERT is a 2D and 3D geostatistics, uncertainty analysis and visualization software package applied to ground water flow and contaminant transport modeling. It is a collection of modules that provides tools for linear regression, univariate statistics, semivariogram analysis, inverse-distance gridding, trend-surface analysis, simple and ordinary kriging and discrete conditional indicator simulation. Graphical user interfaces for MODFLOW and MT3D, ground water flow and contaminant transport models, are provided for streamlined data input and result analysis. Visualization tools are included for displaying data input and output. These include, but are not limited to, 2D and 3D scatter plots, histograms, box and whisker plots, 2D contour maps, surface renderings of 2D gridded data and 3D views of gridded data. By design, UNCERT's graphical user interface and visualization tools facilitate model design and analysis. There are few built in restrictions on data set sizes and each module (with two exceptions) can be run in either graphical or batch mode. UNCERT is in the public domain and is available from the World Wide Web with complete on-line and printable (PDF) documentation. UNCERT is written in ANSI-C with a small amount of FORTRAN77, for UNIX workstations running X-Windows and Motif (or Lesstif). This article discusses the features of each module and demonstrates how they can be used individually and in combination. The tools are applicable to a wide range of fields and are currently used by researchers in the ground water, mining, mathematics, chemistry and geophysics, to name a few disciplines. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  6. Experimental evaluation of enthalpy efficiency and gas-phase contaminant transfer in an enthalpy recovery unit with polymer membrane foils

    DEFF Research Database (Denmark)

    Nie, Jinzhe; Yang, Jianrong; Fang, Lei

    2015-01-01

    Experimental studies were conducted in a laboratory setting to investigate the enthalpy efficiency and gas-phase contaminant transfer in a polymer membrane enthalpy recovery unit. One commercially available polymer membrane enthalpy recovery unit was used as a reference unit. Simulated indoor air...... and outdoor air by twin chambers was connected to the unit. Three chemical gases were dosed to the indoor exhaust air to mimic indoor air contaminants. Based on the measurements of temperature, humidity ratio, and contaminant concentrations of the indoor exhaust air and outdoor air supply upstream...

  7. Field research program for unsaturated flow and transport experimentation

    International Nuclear Information System (INIS)

    Tidwell, V.C.; Rautman, C.A.; Glass, R.J.

    1992-01-01

    As part of the Yucca Mountain Site Characterization Project, a field research program has been developed to refine and validate models for flow and transport through unsaturated fractured rock. Validation of these models within the range of their application for performance assessment requires a more sophisticated understanding of the processes that govern flow and transport within fractured porous media than currently exists. In particular, our research is prioritized according to understanding and modeling processes that, if not accurately incorporated into performance assessment models, would adversely impact the project's ability to evaluate repository performance. For this reason, we have oriented our field program toward enhancing our understanding of scaling processes as they relate to effective media property modeling, as well as to the conceptual modeling of complex flow and transport phenomena

  8. A risk-informed basis for establishing non-fixed surface contamination limits for spent fuel transportation casks

    International Nuclear Information System (INIS)

    Rawl, R.R.; Eckerman, K.F.; Bogard, J.S.; Cook, J.R.

    2004-01-01

    The current limits for non-fixed contamination on packages used to transport radioactive materials were introduced in the 1961 edition of the International Atomic Energy Agency (IAEA) transport regulations and were based on radiation protection guidance and practices in use at that time. The limits were based on exposure scenarios leading to intakes of radionuclides by inhalation and external irradiation of the hands. These considerations are collectively referred to as the Fairbairn model. Although formulated over 40 years ago, the model remains unchanged and is still the basis of current regulatory-derived limits on package non-fixed surface contamination. There can also be doses that while not resulting directly from the contamination, are strongly influenced by and attributable to transport regulatory requirements for contamination control. For example, actions necessary to comply with the current derived limits for light-water-reactor (LWR) spent nuclear fuel (SNF) casks can result in significant external doses to workers. This is due to the relatively high radiation levels around the loaded casks, where workers must function during the measurement of contamination levels and while decontaminating the cask. In order to optimize the total dose received due to compliance with cask contamination levels, it is necessary to take into account all the doses that vary as a result of the regulatory limit. Limits for non-fixed surface contamination on spent fuel casks should be established by using a model that considers and optimizes the appropriate exposure scenarios both in the workplace and in the public environment. A risk-informed approach is needed to ensure optimal use of personnel and material resources for SNF-based packaging operations. This paper is a summary of a study sponsored by the US Nuclear Regulatory Commission and performed by Oak Ridge National Laboratory that examined the dose implications for removable surface contamination limits on spent fuel

  9. Characterizing, for packaging and transport, large objects contaminated by radioactive material having a limited A2 value

    International Nuclear Information System (INIS)

    Pope, R.B.; Shappert, L.B.; Michelhaugh, R.D.; Cash, J.M.; Best, R.E.

    1998-02-01

    The International Atomic Energy Agency (IAEA) Regulations for the safe packaging and transportation of radioactive materials follow a graded approach to the requirements for both packaging and controls during transport. The concept is that, the lower the risk posed to the people and the environment by the contents, (1) the less demanding are the packaging requirements and (2) the smaller in number are the controls imposed on the transport of the material. There are likely to be a great number of situations arising in coming years when large objects, contaminated with radioactive material having unlimited A 2 values will result from various decommissioning and decontamination (D and D) activities and will then require shipment from the D and D site to a disposal site. Such situations may arise relatively frequently during the cleanup of operations involving mining, milling, feedstock, and uranium enrichment processing facilities. Because these objects are contaminated with materials having an unlimited A 2 value they present a low radiological risk to worker and public safety and to the environment during transport. However, when these radioactive materials reside on the surfaces of equipment and other large objects, where the equipment and objects themselves are not radioactive, the radioactive materials appear as surface contamination and, if the contaminated object is categorized as a surface contaminated object, it would need to be packaged for shipment according to the requirements of the Regulations for SCO. Despite this categorization, alternatives may be available which will allow these contaminants, when considered by themselves for packaging and transport, to be categorized as either (1) a limited quantity of radioactive material to be shipped in an excepted package or (2) low specific activity (LSA) materials to be shipped in an IP-1 package or possibly even shipped unpackaged. These options are discussed in this paper

  10. Assessment of risks and costs associated with transportation of US Department of Energy radioactively contaminated carbon steel

    International Nuclear Information System (INIS)

    Chen, S.-Y.; Arnish, J.J.; Nieves, L.A.; Folga, S.M.

    1996-09-01

    This report provides a preliminary assessment of potential human health risks and develops unit risks and costs for transporting radioactively contaminated carbon steel (RCCS) scrap between U.S. Department of Energy (DOE) sites. The RCCS would be generated from DOE activities (current or future) and from decontamination and decommissioning of DOE facilities. The estimates of transportation system risk reflect preliminary information regarding the quantities of RCCS at some sites and the spectrum of activity in RCCS at various types of DOE facilities

  11. Tracking the origin and dispersion of contaminated sediments transported by rivers draining the Fukushima radioactive contaminant plume

    Directory of Open Access Journals (Sweden)

    H. Lepage

    2015-03-01

    Full Text Available This study was conducted in several catchments draining the main Fukushima Dai-ichi Power Plant contaminant plume in Fukushima prefecture, Japan. We collected soils and sediment drape deposits (n = 128 and investigated the variation in 137Cs enrichment during five sampling campaigns, conducted every six months, which typically occurred after intense erosive events such as typhoons and snowmelt. We show that upstream contaminated soils are eroded during summer typhoons (June–October before being exported during the spring snowmelt (March–April. However, this seasonal cycle of sediment dispersion is further complicated by the occurrence of dam releases that may discharge large amounts of contaminants to the coastal plains during the coming years.

  12. Experimental transport analysis code system in JT-60

    International Nuclear Information System (INIS)

    Hirayama, Toshio; Shimizu, Katsuhiro; Tani, Keiji; Shirai, Hiroshi; Kikuchi, Mitsuru

    1988-03-01

    Transport analysis codes have been developed in order to study confinement properties related to particle and energy balance in ohmically and neutral beam heated plasmas of JT-60. The analysis procedure is divided into three steps as follows: 1) LOOK ; The shape of the plasma boundary is identified with a fast boundary identification code of FBI by using magnetic data, and flux surfaces are calculated with a MHD equilibrium code of SELENE. The diagnostic data are mapped to flux surfaces for neutral beam heating calculation and/or for radial transport analysis. 2) OFMC ; On the basis of transformed data, an orbit following Monte Carlo code of OFMC calculates both profiles of power deposition and particle source of neutral beam injected into a plasma. 3) SCOOP ; In the last stage, a one dimensional transport code of SCOOP solves particle and energy balance for electron and ion, in order to evaluate transport coefficients as well as global parameters such as energy confinement time and the stored energy. The analysis results are provided to a data bank of DARTS that is used to find an overview of important consideration on confinement with a regression analysis code of RAC. (author)

  13. Evidence for the 'grasshopper' effect and fractionation during long-range atmospheric transport of organic contaminants

    International Nuclear Information System (INIS)

    Gouin, T.; Mackay, D.; Jones, K.C.; Harner, T.; Meijer, S.N.

    2004-01-01

    Although there is indisputable evidence that long-range atmospheric transport (LRAT) of organic contaminants occurs on a global scale, uncertainties remain about the detailed mechanism and extent of this phenomenon as well as the physical-chemical properties which facilitate LRAT. In this study, we discuss how mass balance models and monitoring data can contribute to a fuller understanding of the mechanism and extent of LRAT. Specifically we address the issues of 'grasshopping' or 'hopping' (the extent to which molecules are subject to multiple hops as distinct from a single emission-deposition event) and 'global fractionation' (the differing behavior of chemicals as they are transported). It is shown that simple mass balance models can be used to assist the interpretation of monitoring data while also providing an instrument that can be used to assess the LRAT potential and the extent of hopping that organic substances may experience. The available evidence supports the notion that many persistent organic pollutants experience varying degrees of 'hopping' during their environmental journey and as a consequence become fractionated with distance from source. - Evidence for global scale fractionation and hopping of POPs is reviewed

  14. Stochastic analysis of contaminant transport in porous media: analysis of a two-member radionuclide chain

    International Nuclear Information System (INIS)

    Bonano, E.J.; Shipers, L.R.

    1987-01-01

    In this study the authors extend previous stochastic analyses of contaminant transport in geologic media for a single species to a chain of two species. The authors particular application is the quantification of uncertainties due to lack of characterization of the spatial variability of hydrologic parameters on transport of radionuclides from a high-level waste repository to the biosphere. Radionuclide chains can have a significant impact on demonstrating compliance (or violation) of standards regulating the release to the environment accessible to humans. Two approaches for determining the cross-covariance terms in the mean concentration equations are presented. One uses a Taylor expansion to obtain the cross-covariance between the velocity and concentration fluctuations, while the other is based on a Fourier-Laplace double transform method. For the conditions of interest here, the difference between these two approaches are expected to be small. In addition, the variances are calculated in a unique way by solving another associated partial differential equation. A parametric study is carried out to examine the sensitivity of the mean concentration of the two species and their corresponding variances and cross-covariance on the parameters associated with the structure of the stochastic velocity field. It is found that the dependent variables are most sensitive to the intensity and correlation length of the velocity fluctuations. The magnitude of the variances and cross-covariance of the concentrations are proportional to the magnitude of the mean concentrations which depend on inlet concentration boundary conditions

  15. IAEA co-ordinated research programme on the transport of low specific activity materials and surface contaminated objects

    International Nuclear Information System (INIS)

    Gray, I.L.S.

    2000-01-01

    The International Atomic Energy Agency (IAEA) prepares regulations for the safe transport of radioactive material, and periodically revised editions of these are published. These regulations are adopted by individual countries across the world and by international organisations concerned with transport. Whilst it is desirable to have a stable framework of regulatory requirements, there is also a need to take account of technical advances and operational experience and revise the regulations. From time to time Co-ordinated Research Programmes (CRP) are established to investigate particular areas of the regulations that are giving concern. In 1996 the IAEA Standing Advisory Group on the Transport of Radioactive Material (SAGSTRAM) concluded that the requirements for classification, packaging and transport of low specific activity (LSA) material and surface contaminated objects (SCO) did not always have a strong radiation protection basis. Accordingly SAGSTRAM established a CRP with an overall objective to develop a dose-based approach for establishing LSA/SCO requirements. Six countries are participating in this CRP. Brazil, Canada, France, Germany, United Kingdom and United States. Each country is carrying out work that is outlined in agreements with the IAEA, with the work aimed at meeting the specific objective of the agreement and also contributing to achieving the overall objective of the CRP. Completion of the CRP usually involves the preparation of an IAEA TECDOC by a Consultant Services Meeting (CSM), and this TECDOC will summarise the work performed under the CRP and include any recommendations made by the CRP. Following the establishment of the CRP in 1997, the first Research Co-ordination Meeting (RCM) was held in December 1997. The second RCM was held in March 1999, with the final RCM planned for the end of 2000. The work being carried out by Brazil and Canada is focused upon the transport of uranium and thorium ores, and is a mixture of theoretical and

  16. Understanding Contaminant Transport Pathways at Rocky Flats - A Basis for the Remediation Strategy

    International Nuclear Information System (INIS)

    Paton, Ian

    2008-01-01

    The Rocky Flats Environmental Technology Site (RFETS) is a Department of Energy facility located approximately 16 miles northwest of Denver, Colorado. Processing and fabrication of nuclear weapons components occurred at Rocky Flats from 1952 through 1989. Operations at the Site included the use of several radionuclides, including plutonium-239/240 (Pu), americium-241 (Am), and various uranium (U) isotopes, as well as several types of chlorinated solvents. The historic operations resulted in legacy contamination, including contaminated facilities, process waste lines, buried wastes and surface soil contamination. Decontamination and removal of buildings at the site was completed in late 2005, culminating more than ten years of active environmental remediation work. The Corrective Action Decision/Record of Decision was subsequently approved in 2006, signifying regulatory approval and closure of the site. The use of RFETS as a National Wildlife Refuge is scheduled to be in full operation by 2012. To develop a plan for remediating different types of radionuclide contaminants present in the RFETS environment required understanding the different environmental transport pathways for the various actinides. Developing this understanding was the primary objective of the Actinide Migration Evaluation (AME) project. Findings from the AME studies were used in the development of RFETS remediation strategies. The AME project focused on issues of actinide behavior and mobility in surface water, groundwater, air, soil and biota at RFETS. For the purposes of the AME studies, actinide elements addressed included Pu, Am, and U. The AME program, funded by DOE, brought together personnel with a broad range of relevant expertise in technical investigations. The AME advisory panel identified research investigations and approaches that could be used to solve issues related to actinide migration at the Site. An initial step of the AME was to develop a conceptual model to provide a

  17. Experimental study of contamination by inhalation of radioactive iodine aerosols. Biological balance

    International Nuclear Information System (INIS)

    Marble, G.

    1968-01-01

    Several articles have been published concerning research into contamination produced by inhalation of radioactive iodine aerosols in monkeys. Results dealing with the biological balance of this contamination are presented and discussed in this report. (author) [fr

  18. Contaminant transport and accumulation in Massachusetts Bay and Boston Harbor; a summary of U.S. Geological Survey studies

    Science.gov (United States)

    Butman, Bradford; Bothner, Michael H.; Hathaway, J.C.; Jenter, H.L.; Knebel, H.J.; Manheim, F.T.; Signell, R.P.

    1992-01-01

    The U.S. Geological Survey (USGS) is conducting studies in Boston Harbor, Massachusetts Bay, and Cape Cod Bay designed to define the geologic framework of the region and to understand the transport and accumulation of contaminated sediments. The region is being studied because of environmental problems caused by the introduction of wastes for a long time, because a new ocean outfall (to begin operation in 1995) will change the location for disposal of treated Boston sewage from Boston Harbor into Massachusetts Bay, and because of the need to understand the transport of sediments and associated contaminants in order to address a wide range of management questions. The USGS effort complements and is closely coordinated with the research and monitoring studies supported by the Massachusetts Environmental Trust, the Massachusetts Bays Program, and by the Massachusetts Water Resources Authority. The USGS study includes (1) geologic mapping, (2) circulation studies, (3) long-term current and sediment transport observations, (4) measurements of contaminant inventories and rates of sediment mixing and accumulation, (5) circulation modeling, (6) development of a contaminated sediments data base, and (7) information exchange. A long-term objective of the program is to develop a predictive capability for sediment transport and accumulation.

  19. Impact of runoff infiltration on contaminant accumulation and transport in the soil/filter media of Sustainable Urban Drainage Systems: A literature review.

    Science.gov (United States)

    Tedoldi, Damien; Chebbo, Ghassan; Pierlot, Daniel; Kovacs, Yves; Gromaire, Marie-Christine

    2016-11-01

    The increasing use of Sustainable Urban Drainage Systems (SUDS) for stormwater management raises some concerns about the fate of ubiquitous runoff micropollutants in soils and their potential threat to groundwater. This question may be addressed either experimentally, by sampling and analyzing SUDS soil after a given operating time, or with a modeling approach to simulate the fate and transport of contaminants. After briefly reminding the processes responsible for the retention, degradation, or leaching of several urban-sourced contaminants in soils, this paper presents the state of the art about both experimental and modeling assessments. In spite of noteworthy differences in the sampling protocols, the soil parameters chosen as explanatory variables, and the methods used to evaluate the site-specific initial concentrations, most investigations undoubtedly evidenced a significant accumulation of metals and/or hydrocarbons in SUDS soils, which in the majority of the cases appears to be restricted to the upper 10 to 30cm. These results may suggest that SUDS exhibit an interesting potential for pollution control, but antinomic observations have also been made in several specific cases, and the inter-site concentration variability is still difficult to appraise. There seems to be no consensus regarding the level of complexity to be used in models. However, the available data deriving from experimental studies is generally limited to the contamination profiles and a few parameters of the soil, as a result of which "complex" models (including colloid-facilitated transport for example) appear to be difficult to validate before using them for predictive evaluations. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Outcomes of experimental researches on stainless steel decontamination from radioactive contamination using electric slag remelting method

    International Nuclear Information System (INIS)

    Vurim, A.D.; Pakhnitz, A.V.; Trukhachev, A.G.; Bukhtoyarov, O.I.; Goncharov, A.Ye.

    2003-01-01

    Full text: Institute of Atomic Energy prepared and conducted the experiments the purpose of researching a possibility of applying of stainless steel electric slag remelting for its decontamination from radioactive contamination. The activities were conducted at participating of the specialists of Kurgan State University, Kurgan (Russian Federation). A stand, which includes the electroslag furnace (power - 150 kW, current - to 3000 A) and auxiliary equipment (the system of common and special ventilation, system of remote control, system of parameters measuring and registering and others) was created to conduct the experiments. The properties of slag compositions were researched in the course of experiments preparation. Oxide (CaO-Al 2 O 3 - CaO-SiO 2 - MgO-B 2 O 3 ) and fluoride-oxide (CaF 2 -SiO 2 - MgF 2 -SiO 2 ) slag systems and some their modifications were chosen to research physical and chemical properties. Physical and chemical properties of the slag systems were experimentally researched and it included: measuring of surface tension using the method of maximum pressure in a gas bubble (at the same time density was measured); measuring of slag alloys electrical conductivity; measuring of melt volt-ampere characteristics. The flue tubes of high temperature reactor gas cooling KET technological channels were chosen as a source of radioactive contaminated stainless steel. This reactor is meant for testing of the fuel pin and FA of the nuclear pulse propulsion. Decontamination effect for all the remelted flue tubes was indirectly confirmed by the outcomes of measuring of radioactive radiation dose rate of the materials, extracted of the crystallizer after experiments finishing. The outcomes of the experiments show that the following processes pass at electroslag remelting of radioactively contaminated steel: uranium extraction from steel; uranium transfer from steel to slag; saving or insignificant modification of steel initial composition; radionuclides deposing

  1. Simulations of groundwater flow, transport, and age in Albuquerque, New Mexico, for a study of transport of anthropogenic and natural contaminants (TANC) to public-supply wells

    Science.gov (United States)

    Heywood, Charles E.

    2013-01-01

    Vulnerability to contamination from manmade and natural sources can be characterized by the groundwater-age distribution measured in a supply well and the associated implications for the source depths of the withdrawn water. Coupled groundwater flow and transport models were developed to simulate the transport of the geochemical age-tracers carbon-14, tritium, and three chlorofluorocarbon species to public-supply wells in Albuquerque, New Mexico. A separate, regional-scale simulation of transport of carbon-14 that used the flow-field computed by a previously documented regional groundwater flow model was calibrated and used to specify the initial concentrations of carbon-14 in the local-scale transport model. Observations of the concentrations of each of the five chemical species, in addition to water-level observations and measurements of intra-borehole flow within a public-supply well, were used to calibrate parameters of the local-scale groundwater flow and transport models. The calibrated groundwater flow model simulates the mixing of “young” groundwater, which entered the groundwater flow system after 1950 as recharge at the water table, with older resident groundwater that is more likely associated with natural contaminants. Complexity of the aquifer system in the zone of transport between the water table and public-supply well screens was simulated with a geostatistically generated stratigraphic realization based upon observed lithologic transitions at borehole control locations. Because effective porosity was simulated as spatially uniform, the simulated age tracers are more efficiently transported through the portions of the simulated aquifer with relatively higher simulated hydraulic conductivity. Non-pumping groundwater wells with long screens that connect aquifer intervals having different hydraulic heads can provide alternate pathways for contaminant transport that are faster than the advective transport through the aquifer material. Simulation of

  2. An Iterative Ensemble Kalman Filter with One-Step-Ahead Smoothing for State-Parameters Estimation of Contaminant Transport Models

    KAUST Repository

    Gharamti, M. E.; Ait-El-Fquih, Boujemaa; Hoteit, Ibrahim

    2015-01-01

    Numerical experiments are conducted with a two-dimensional synthetic subsurface transport model simulating the migration of a contaminant plume in a heterogenous aquifer domain. Contaminant concentration data are assimilated to estimate both the contaminant state and the hydraulic conductivity field. Assimilation runs are performed under imperfect modeling conditions and various observational scenarios. Simulation results suggest that the proposed scheme efficiently recovers both the contaminant state and the aquifer conductivity, providing more accurate estimates than the standard Joint and Dual EnKFs in all tested scenarios. Iterating on the update step of the new scheme further enhances the proposed filter’s behavior. In term of computational cost, the new Joint-EnKF is almost equivalent to that of the Dual-EnKF, but requires twice more model integrations than the standard Joint-EnKF.

  3. Zinc and lead transfer in a contaminated roadside soil: Experimental study and modeling

    International Nuclear Information System (INIS)

    Hanna, K.; Lassabatere, L.; Bechet, B.

    2009-01-01

    The application of a surface complexation model to simulate the sorption of metals on single sorbents is very well investigated, but very little is known regarding the use of surface complexation modeling to simulate the metal mobility in contaminated roadside soils. The overall objective of this study was to examine whether the use of the surface complexation model (SCM) could correctly describe the migration of zinc and lead in roadside soil under various physicochemical conditions. The release and transport of Zn and Pb was studied by means of batch reactors and saturated chromatography columns. Soil batch experiments were conducted to evaluate the effects of pH variation and ionic strength on the metal mobility from soil. Elution of Pb and Zn was examined in column experiments by using acetic acid at pH5 and EDTA at pH7. The modeling work has focused on the development of a SCM using MINTEQ2 database incorporated in PHREEQC-2 to describe the interactions between trace metals and the main mineral soil components (quartz, iron and aluminum oxides). In this study, it was found that the SCM was able to simulate the mobility of metals from soil by assuming one mononuclear surface reaction between one solution species (Me 2+ ) and one type of site on the surface of soil dominant sorbents

  4. Phase I Contaminant Transport Parameters for the Groundwater Flow and Contaminant Transport Model of Corrective Action Unit 97: Yucca Flat/Climax Mine, Nevada Test Site, Nye County, Nevada, Revision 0

    International Nuclear Information System (INIS)

    John McCord

    2007-01-01

    This report documents transport data and data analyses for Yucca Flat/Climax Mine CAU 97. The purpose of the data compilation and related analyses is to provide the primary reference to support parameterization of the Yucca Flat/Climax Mine CAU transport model. Specific task objectives were as follows: (1) Identify and compile currently available transport parameter data and supporting information that may be relevant to the Yucca Flat/Climax Mine CAU. (2) Assess the level of quality of the data and associated documentation. (3) Analyze the data to derive expected values and estimates of the associated uncertainty and variability. The scope of this document includes the compilation and assessment of data and information relevant to transport parameters for the Yucca Flat/Climax Mine CAU subsurface within the context of unclassified source-term contamination. Data types of interest include mineralogy, aqueous chemistry, matrix and effective porosity, dispersivity, matrix diffusion, matrix and fracture sorption, and colloid-facilitated transport parameters

  5. Phase I Contaminant Transport Parameters for the Groundwater Flow and Contaminant Transport Model of Corrective Action Unit 97: Yucca Flat/Climax Mine, Nevada Test Site, Nye County, Nevada, Revision 0

    Energy Technology Data Exchange (ETDEWEB)

    John McCord

    2007-09-01

    This report documents transport data and data analyses for Yucca Flat/Climax Mine CAU 97. The purpose of the data compilation and related analyses is to provide the primary reference to support parameterization of the Yucca Flat/Climax Mine CAU transport model. Specific task objectives were as follows: • Identify and compile currently available transport parameter data and supporting information that may be relevant to the Yucca Flat/Climax Mine CAU. • Assess the level of quality of the data and associated documentation. • Analyze the data to derive expected values and estimates of the associated uncertainty and variability. The scope of this document includes the compilation and assessment of data and information relevant to transport parameters for the Yucca Flat/Climax Mine CAU subsurface within the context of unclassified source-term contamination. Data types of interest include mineralogy, aqueous chemistry, matrix and effective porosity, dispersivity, matrix diffusion, matrix and fracture sorption, and colloid-facilitated transport parameters.

  6. Perched aquifers - their potential impact on contaminant transport in the southern High Plains, Texas

    International Nuclear Information System (INIS)

    Mullican, W.F. III; Fryar, A.E.; Johns, N.D.

    1993-01-01

    Understanding the hydrogeology and hydrochemistry of perched aquifers at potential and known contaminated waste sites has become increasingly important because of the impact these aquifers may have on contaminant transport independent of regional aquifer processes. Investigations of a perched aquifer above the Ogallala aquifer are being conducted in the region of the U.S. Department of Energy's Pantex Plant, a proposed Superfund site, located approximately 20 mi northeast of Amarillo, Texas. Since the early 1950s, a small playa basin located on the Pantex Plant has been used as a waste-water discharge pond with daily discharge rates ranging from 400,000 to 1 million gal. The focus of this investigation is an unconfined, perched aquifer that overlies a thick silty clay sequence within the upper, mostly unsaturated part of the Ogallala Formation (Neogene). In the area of the Pantex Plant, measured depths to the perched aquifer range from 200 to 300 ft below land surface, whereas depth to the regional Ogallala aquifer ranges from 375 to 500 ft. The potentiometric surface of the perched aquifer typically represents groundwater mounds proximal to the playas and thins into trough in the interplaya areas. Hydrologic gradients of the primary mound under investigation are relatively high, ranging from 28 to 45 ft/mi. Calculated transmissivities have a geometric mean of 54 ft 2 /day, with saturated thicknesses ranging from 4 to 1000 ft. Modeling of the perched aquifer was designed to determine how much, if any, discharge to the small playa basin has enhanced recharge to the perched aquifers and increased the vertical and lateral extent of the perched aquifer. Preliminary results indicate that measurements of vertical conductance through the perching silty-clay sequence and recharge rates through playas are critical for calibrating the model. Accurate delineation of rates and flow directions in the perched aquifer is critical to any successful remediation effort

  7. Notification determining details of technical standards concerning transport of radioisotopes or goods contaminated by radioisotopes in works or enterprises

    International Nuclear Information System (INIS)

    1981-01-01

    This rule is established under the provisions of the regulation for the execution of the law on the prevention of radiation injuries by radioisotopes. Terms are used in this rule for the same meanings as in the regulation. The limit of the concentration of radioisotopes in the goods contaminated by these isotopes which are not required to be sealed in containers defined by the Director General of the Science and Technology Agency is 1/10,000 of the value A 2 under the notification determining the details of technical standards concerning the transport of radioisotopes or the goods contaminated by radioisotopes outside works or enterprises. The application for the permission of transporting the goods which are highly difficult to be sealed in containers shall list names and addresses, the kinds, quantities, shapes and properties of the transported goods contaminated by radioisotopes, etc. The radiation dose rate of transported goods and vehicles under the regulation is 200 milli-rem an hour on the surfaces of these goods, vehicles and containers, and 10 milli-rem an hour at the distance of 1 meter from their surfaces. The permissible exposure dose of the persons engaging in transport is 1.5 rem a year. Dangerous goods, signs, and the application for the approval of special measures are specified, respectively. (Okada, K.)

  8. 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

  9. Modeling the Influence of Variable Tributary Inflow on Circulation and Contaminant Transport in a Water Supply Reservoir

    Science.gov (United States)

    Nguyen, L. H.; Wildman, R.

    2012-12-01

    This study characterizes quantitatively the flow and mixing regimes of a water supply reservoir, while also conducting numerical tracer experiments on different operation scenarios. We investigate the effects of weather events on water quality via storm water inflows. Our study site the Kensico Reservoir, New York, the penultimate reservoir of New York City's water supply, is never filtered and thus dependent on stringent watershed protection. This reservoir must meet federal drinking water standards under changing conditions such as increased suburban, commercial, and highway developments that are much higher than the rest of the watershed. Impacts from these sources on water quality are magnified by minor tributary flows subject to contaminants from development projects as other tributaries providing >99% of water to this reservoir are exceedingly clean due to management practices upstream. These threats, coupled with possible changes in the frequency/intensity of weather events due to climate change, increase the potential for contaminants to enter the reservoir and drinking water intakes. This situation provides us with the unique ability to study the effects of weather events on water quality via insignificant storm water inflows, without influence from the major tributaries due to their pristine water quality characteristics. The concentration of contaminants at the drinking water intake depends partially on transport from their point of entry in the reservoir. Thus, it is crucial to understand water circulation in this reservoir and to estimate residence times and water ages at different locations and under different hydrologic scenarios. We described water age, residence time, thermal structure, and flow dynamics of tributary plumes in Kensico Reservoir during a 22-year simulation period using a two-dimensional hydrodynamic and water quality model (CE-QUAL-W2). Our estimates of water age can reach a maximum of ~300 days in deep-reservoir-cells, with

  10. Experimental study of electron temperature gradient influence on impurity turbulent transport in fusion plasmas

    International Nuclear Information System (INIS)

    Villegas, D.

    2010-01-01

    Understanding impurity transport is a key to an optimal regime for a future fusion device. In this thesis, the theoretical and experimental influence of the electron temperature gradient R/L Te on heavy impurity transport is analyzed both in Tore Supra and ASDEX Upgrade. The electron temperature profile is modified locally by heating the plasma with little ECRH power deposited at two different radii. Experimental results have been obtained with the impurity transport code (ITC) which has been completed with a genetic algorithm allowing to determine the transport coefficient profiles with more accuracy. Transport coefficient profiles obtained by a quasilinear gyrokinetic code named QuaLiKiz are consistent with the experimental ones despite experimental uncertainties on gradients. In the core dominated by electron modes, the lower R/L Te the lower the nickel diffusion coefficient. The latter tends linearly to the neoclassical level when the instability threshold is approached. The experimental threshold is in agreement with the one computed by QuaLiKiz. Further out, where the plasma is dominated by ITG, which are independent of R/L Te , both experimental and simulated results show no modification in the diffusion coefficient profile. Furthermore, the convection velocity profile is not modified. This is attributed to a very small contribution of the thermodiffusion (1/Z dependence) in the total convection. On ASDEX, the preliminary results, very different from the Tore Supra ones, show a internal transport barrier for impurities located at the same radius as the strong ECRH power deposit. (author) [fr

  11. Combined local and systemic antibiotic delivery improves eradication of wound contamination: An animal experimental model of contaminated fracture.

    Science.gov (United States)

    Rand, B C C; Penn-Barwell, J G; Wenke, J C

    2015-10-01

    Systemic antibiotics reduce infection in open fractures. Local delivery of antibiotics can provide higher doses to wounds without toxic systemic effects. This study investigated the effect on infection of combining systemic with local antibiotics via polymethylmethacrylate (PMMA) beads or gel delivery. An established Staphylococcus aureus contaminated fracture model in rats was used. Wounds were debrided and irrigated six hours after contamination and animals assigned to one of three groups, all of which received systemic antibiotics. One group had local delivery via antibiotic gel, another PMMA beads and the control group received no local antibiotics. After two weeks, bacterial levels were quantified. Combined local and systemic antibiotics were superior to systemic antibiotics alone at reducing the quantity of bacteria recoverable from each group (p = 0.002 for gel; p = 0.032 for beads). There was no difference in the bacterial counts between bead and gel delivery (p = 0.62). These results suggest that local antibiotics augment the antimicrobial effect of systemic antibiotics. Although no significant difference was found between vehicles, gel delivery offers technical advantages with its biodegradable nature, ability to conform to wound shape and to deliver increased doses. Further study is required to see if the gel delivery system has a clinical role. ©2015 The British Editorial Society of Bone & Joint Surgery.

  12. On indoor radon contamination monitoring with SSNTDs: Experimental results concerning plate-out and self-plate-out effects

    International Nuclear Information System (INIS)

    Bigazzi, G.; Hadler, J.C.; Paulo, S.R.

    1989-01-01

    Measurements of the alpha activities of 222 Rn and its daughters were performed, both inside a glass recipient and in closed rooms, employing SSNTDs (CR-39 and nuclear emulsion). The experimental results presented here show that plate-out and self-plate-out effects should be taken into account when SSNTDs are employed in indoor radon contamination monitoring. (orig.)

  13. Impact of porosity variation on diffusive transport: experimentation vs simulation

    International Nuclear Information System (INIS)

    Fatnassi, Ikram

    2015-01-01

    Reactions induced by the diffusion of reactants from different sources may alter rock confinement properties, and are therefore critical processes to assess short-term and long-term behaviour of rocks displaying a low permeability, such as argillites which are used as barriers in underground storage installation. In order to test transport-chemistry codes based on a continuous approach, the author of this research thesis reports the development and performance of simplest as possible experiments of sealing/dissolution diffusion, by using porous media of increasing complexity: compact sand, sintered glass, stoneware, chalk, until a material close to that envisaged within the frame of a storage like a Tournemire argillite. The principle of these experiments relies on the characterisation of the diffusive behaviour of an inert tracer within a porous medium submitted to dissolution reactions (attack of a carbonate matrix by an acid solution) and/or precipitation of mineral compounds (calcium oxalate, gypsum or barite) which results in an evolution of porosity and a modification of the diffusive transport of the studied tracer. At the end of the experiment, porous media and precipitates are characterised by SEM-EDS [fr

  14. EVALUATION OF BIOAEROSOL COMPONENTS, GENERATION FACTORS, AND AIRBORNE TRANSPORT ASSOCIATED WITH LIME TREATMENT OF CONTAMINATED SEDIMENT

    Science.gov (United States)

    Lime treatment has been used in contaminated sediment management activities for many purposes such as dewatering, improvement of physical properties, and reducing contaminant mobility. Exothermic volatilization of volatile organic compounds from lime-treated sediment is well kno...

  15. Contaminant flow and transport simulation in cracked porous media using locally conservative schemes

    KAUST Repository

    Song, Pu; Sun, Shuyu

    2012-01-01

    The purpose of this paper is to analyze some features of contaminant flow passing through cracked porous medium, such as the influence of fracture network on the advection and diffusion of contaminant species, the impact of adsorption on the overall

  16. Contamination of an arctic terrestrial food web with marine-derived persistent organic pollutants transported by breeding seabirds

    International Nuclear Information System (INIS)

    Choy, Emily S.; Kimpe, Linda E.; Mallory, Mark L.; Smol, John P.; Blais, Jules M.

    2010-01-01

    At Cape Vera, Devon Island (Nunavut, Canada), a colony of northern fulmars (Fulmarus glacialis) concentrates and releases contaminants through their guano to the environment. We determined whether persistent organic pollutants (POPs) from seabirds were transferred to coastal food webs. Snow buntings (Plectrophenax nivalis) were the most contaminated species, with ΣPCB and ΣDDT (mean: 168, 106 ng/g ww) concentrations surpassing environmental guidelines for protecting wildlife. When examined collectively, PCB congeners and DDT in jewel lichen (Xanthoria elegans) were lower in samples taken farther from the seabird colony, and increased with increasing δ 15 N values. However, only concentrations of p'p-DDE:ΣDDT and PCB-95 were significantly correlated inversely with distance from the seabird cliffs. Linkages between marine-derived POPs and their concentrations in terrestrial mammals were less clear. Our study provides novel contaminant data for these species and supports biovector transport as a source of organic contaminants to certain components of the terrestrial food web. - This study provides evidence of contaminant transport by seabirds to a coastal Arctic food web.

  17. An adaptive hybrid EnKF-OI scheme for efficient state-parameter estimation of reactive contaminant transport models

    KAUST Repository

    El Gharamti, Mohamad; Valstar, Johan R.; Hoteit, Ibrahim

    2014-01-01

    Reactive contaminant transport models are used by hydrologists to simulate and study the migration and fate of industrial waste in subsurface aquifers. Accurate transport modeling of such waste requires clear understanding of the system's parameters, such as sorption and biodegradation. In this study, we present an efficient sequential data assimilation scheme that computes accurate estimates of aquifer contamination and spatially variable sorption coefficients. This assimilation scheme is based on a hybrid formulation of the ensemble Kalman filter (EnKF) and optimal interpolation (OI) in which solute concentration measurements are assimilated via a recursive dual estimation of sorption coefficients and contaminant state variables. This hybrid EnKF-OI scheme is used to mitigate background covariance limitations due to ensemble under-sampling and neglected model errors. Numerical experiments are conducted with a two-dimensional synthetic aquifer in which cobalt-60, a radioactive contaminant, is leached in a saturated heterogeneous clayey sandstone zone. Assimilation experiments are investigated under different settings and sources of model and observational errors. Simulation results demonstrate that the proposed hybrid EnKF-OI scheme successfully recovers both the contaminant and the sorption rate and reduces their uncertainties. Sensitivity analyses also suggest that the adaptive hybrid scheme remains effective with small ensembles, allowing to reduce the ensemble size by up to 80% with respect to the standard EnKF scheme. © 2014 Elsevier Ltd.

  18. Contamination of an arctic terrestrial food web with marine-derived persistent organic pollutants transported by breeding seabirds

    Energy Technology Data Exchange (ETDEWEB)

    Choy, Emily S., E-mail: echoy087@uottawa.c [Program for Chemical and Environmental Toxicology, Department of Biology, University of Ottawa, Ottawa, ON, K1N 6N5 (Canada); Kimpe, Linda E., E-mail: linda.kimpe@uottawa.c [Program for Chemical and Environmental Toxicology, Department of Biology, University of Ottawa, Ottawa, ON, K1N 6N5 (Canada); Mallory, Mark L., E-mail: mark.mallory@ec.gc.c [Canadian Wildlife Service, Environment Canada, Iqaluit, NU, X0A 0H0 (Canada); Smol, John P., E-mail: smolj@queensu.c [Paleoecological Environmental Assessment and Research Lab (PEARL), Department of Biology, Queen' s University, Kingston, ON, K7L 3N6 (Canada); Blais, Jules M., E-mail: jules.blais@uottawa.c [Program for Chemical and Environmental Toxicology, Department of Biology, University of Ottawa, Ottawa, ON, K1N 6N5 (Canada)

    2010-11-15

    At Cape Vera, Devon Island (Nunavut, Canada), a colony of northern fulmars (Fulmarus glacialis) concentrates and releases contaminants through their guano to the environment. We determined whether persistent organic pollutants (POPs) from seabirds were transferred to coastal food webs. Snow buntings (Plectrophenax nivalis) were the most contaminated species, with {Sigma}PCB and {Sigma}DDT (mean: 168, 106 ng/g ww) concentrations surpassing environmental guidelines for protecting wildlife. When examined collectively, PCB congeners and DDT in jewel lichen (Xanthoria elegans) were lower in samples taken farther from the seabird colony, and increased with increasing {delta}{sup 15}N values. However, only concentrations of p'p-DDE:{Sigma}DDT and PCB-95 were significantly correlated inversely with distance from the seabird cliffs. Linkages between marine-derived POPs and their concentrations in terrestrial mammals were less clear. Our study provides novel contaminant data for these species and supports biovector transport as a source of organic contaminants to certain components of the terrestrial food web. - This study provides evidence of contaminant transport by seabirds to a coastal Arctic food web.

  19. An adaptive hybrid EnKF-OI scheme for efficient state-parameter estimation of reactive contaminant transport models

    KAUST Repository

    El Gharamti, Mohamad

    2014-09-01

    Reactive contaminant transport models are used by hydrologists to simulate and study the migration and fate of industrial waste in subsurface aquifers. Accurate transport modeling of such waste requires clear understanding of the system\\'s parameters, such as sorption and biodegradation. In this study, we present an efficient sequential data assimilation scheme that computes accurate estimates of aquifer contamination and spatially variable sorption coefficients. This assimilation scheme is based on a hybrid formulation of the ensemble Kalman filter (EnKF) and optimal interpolation (OI) in which solute concentration measurements are assimilated via a recursive dual estimation of sorption coefficients and contaminant state variables. This hybrid EnKF-OI scheme is used to mitigate background covariance limitations due to ensemble under-sampling and neglected model errors. Numerical experiments are conducted with a two-dimensional synthetic aquifer in which cobalt-60, a radioactive contaminant, is leached in a saturated heterogeneous clayey sandstone zone. Assimilation experiments are investigated under different settings and sources of model and observational errors. Simulation results demonstrate that the proposed hybrid EnKF-OI scheme successfully recovers both the contaminant and the sorption rate and reduces their uncertainties. Sensitivity analyses also suggest that the adaptive hybrid scheme remains effective with small ensembles, allowing to reduce the ensemble size by up to 80% with respect to the standard EnKF scheme. © 2014 Elsevier Ltd.

  20. Modelling the transport of solid contaminants originated from a point source

    Science.gov (United States)

    Salgueiro, Dora V.; Conde, Daniel A. S.; Franca, Mário J.; Schleiss, Anton J.; Ferreira, Rui M. L.

    2017-04-01

    The solid phases of natural flows can comprise an important repository for contaminants in aquatic ecosystems and can propagate as turbidity currents generating a stratified environment. Contaminants can be desorbed under specific environmental conditions becoming re-suspended, with a potential impact on the aquatic biota. Forecasting the distribution of the contaminated turbidity current is thus crucial for a complete assessment of environmental exposure. In this work we validate the ability of the model STAV-2D, developed at CERIS (IST), to simulate stratified flows such as those resulting from turbidity currents in complex geometrical environments. The validation involves not only flow phenomena inherent to flows generated by density imbalance but also convective effects brought about by the complex geometry of the water basin where the current propagates. This latter aspect is of paramount importance since, in real applications, currents may propagate in semi-confined geometries in plan view, generating important convective accelerations. Velocity fields and mass distributions obtained from experiments carried out at CERIS - (IST) are used as validation data for the model. The experimental set-up comprises a point source in a rectangular basin with a wall placed perpendicularly to the outer walls. Thus generates a complex 2D flow with an advancing wave front and shocks due to the flow reflection from the walls. STAV-2D is based on the depth- and time-averaged mass and momentum equations for mixtures of water and sediment, understood as continua. It is closed in terms of flow resistance and capacity bedload discharge by a set of classic closure models and a specific high concentration formulation. The two-layer model is derived from layer-averaged Navier-Stokes equations, resulting in a system of layer-specific non-linear shallow-water equations, solved through explicit first or second-order schemes. According to the experimental data for mass distribution, the

  1. Growth Inhibition of Cronobacter sakazakii in Experimentally Contaminated Powdered Infant Formula by Kefir Supernatant.

    Science.gov (United States)

    Kim, Dong-Hyeon; Chon, Jung-Whan; Kang, Il-Byeong; Kim, Hyunsook; Kim, Hong-Seok; Song, Kwang-Young; Seo, Kun-Ho

    2015-09-01

    Kefir is a type of fermented milk containing lactic and acetic acid bacteria and yeast. In this study, we evaluated the antimicrobial activity of kefir supernatant against Cronobacter sakazakii in powdered infant formula (PIF). In a spot-on-lawn test, the growth of 20 C. sakazakii strains, including 10 clinical and 10 food isolates, was completely inhibited in the presence of kefir supernatant. Significant differences in the diameters of inhibition zones were observed upon treatment with kefir compared with the results for Lactobacillus kefiri and Candida kefyr culture supernatants or solutions of lactic and acetic acid and ethyl alcohol in the agar well diffusion test (P < 0.05). The addition of 100 μl of kefir supernatant to 1 ml of nutrient broth completely inhibited the growth of C. sakazakii, as evaluated by spectrophotometry. The antimicrobial activity of kefir supernatant in experimentally contaminated PIF was also tested; we found no viable C. sakazakii cells remaining in PIF rehydrated with 30% kefir supernatant solution for 1 h, demonstrating that the antimicrobial activity of kefir supernatant against C. sakazakii could be applied in real food samples.

  2. Experimental investigation on blood magnetic contamination in the presence of drug molecules

    International Nuclear Information System (INIS)

    Creanga, D E; Nadejde, C; Iacob, G H

    2009-01-01

    The purpose of the present project was to study the interference of magnetic nanoparticles with drug molecules - rifampicin, used in lung infectious disease and respectively, sodium diclofenac, an antiinflammatory steroid. The controlled magnetic contamination was accomplished using colloidal nanoparticles supplied from diluted magnetic fluids. Various concentrations of diluted aqueous magnetic fluids, based on magnetite cores coated with citric acid and respectively sodium oleate, were tested. The experiment was focused on the capacity of the magnetic nanoparticles to form reversible complexes with the drug molecules, as well as on the monitoring of the nanoparticle-drug complex dynamics, under the action of external magnetic field. The level of released rifampicin ranged between 4 mg/100 ml and 7 mg/100 ml for the magnetic exposure of 20 mT, while the sodium diclofenac decomplexation level was not higher than 2.5 mg/100 ml under magnetic exposure of 60 mT. The experimental arrangement was proved to be an adequate model for the dynamical study of magnetite reversible complexation with drug molecules, evidencing certain specific values of drug concentration and magnetic field induction that favour such interactions.

  3. Experimental investigation on blood magnetic contamination in the presence of drug molecules

    Energy Technology Data Exchange (ETDEWEB)

    Creanga, D E; Nadejde, C [' Al. I. Cuza' University, Faculty of Physics, 11A Blvd. Carol I, RO-700506, Iasi (Romania); Iacob, G H [' Gr. T. Popa' University, Faculty of Biomedical Engineering, Kogalniceanu Street, No. 9-13, RO-700454, Iasi (Romania)], E-mail: nadej_dia@yahoo.com

    2009-05-01

    The purpose of the present project was to study the interference of magnetic nanoparticles with drug molecules - rifampicin, used in lung infectious disease and respectively, sodium diclofenac, an antiinflammatory steroid. The controlled magnetic contamination was accomplished using colloidal nanoparticles supplied from diluted magnetic fluids. Various concentrations of diluted aqueous magnetic fluids, based on magnetite cores coated with citric acid and respectively sodium oleate, were tested. The experiment was focused on the capacity of the magnetic nanoparticles to form reversible complexes with the drug molecules, as well as on the monitoring of the nanoparticle-drug complex dynamics, under the action of external magnetic field. The level of released rifampicin ranged between 4 mg/100 ml and 7 mg/100 ml for the magnetic exposure of 20 mT, while the sodium diclofenac decomplexation level was not higher than 2.5 mg/100 ml under magnetic exposure of 60 mT. The experimental arrangement was proved to be an adequate model for the dynamical study of magnetite reversible complexation with drug molecules, evidencing certain specific values of drug concentration and magnetic field induction that favour such interactions.

  4. Sources of Salmonella on broiler carcasses during transportation and processing: modes of contamination and methods of control.

    Science.gov (United States)

    Corry, Janet E L; Allen, V M; Hudson, W R; Breslin, M F; Davies, R H

    2002-01-01

    The prevalence and types of salmonella in broiler chickens during transportation and during slaughter and dressing were studied. This was part of a comprehensive investigation of salmonellas in two UK poultry companies, which aimed to find the origins and mechanisms of salmonella contamination. Salmonellas were isolated using cultural methods. Serovars of Salmonella detected during rearing were usually also found in a small proportion of birds on the day of slaughter and on the carcasses at various points during processing. There was little evidence of salmonellas spreading to large numbers of carcasses during processing. Many serovars found in the feedmills or hatcheries were also detected in the birds during rearing and/or slaughter. Transport crates were contaminated with salmonellas after washing and disinfection. Prevalence of salmonellas fell in the two companies during this survey. A small number of serovars predominated in the processing plants of each company. These serovars originated from the feed mills. Reasons for transport crate contamination were: (1) inadequate cleaning, resulting in residual faecal soiling; (2) disinfectant concentration and temperature of disinfectant too low; (3) contaminated recycled flume water used to soak the crates. Efforts to control salmonella infection in broilers need to concentrate on crate cleaning and disinfection and hygiene in the feed mills.

  5. 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

  6. HZETRN radiation transport validation using balloon-based experimental data

    Science.gov (United States)

    Warner, James E.; Norman, Ryan B.; Blattnig, Steve R.

    2018-05-01

    The deterministic radiation transport code HZETRN (High charge (Z) and Energy TRaNsport) was developed by NASA to study the effects of cosmic radiation on astronauts and instrumentation shielded by various materials. This work presents an analysis of computed differential flux from HZETRN compared with measurement data from three balloon-based experiments over a range of atmospheric depths, particle types, and energies. Model uncertainties were quantified using an interval-based validation metric that takes into account measurement uncertainty both in the flux and the energy at which it was measured. Average uncertainty metrics were computed for the entire dataset as well as subsets of the measurements (by experiment, particle type, energy, etc.) to reveal any specific trends of systematic over- or under-prediction by HZETRN. The distribution of individual model uncertainties was also investigated to study the range and dispersion of errors beyond just single scalar and interval metrics. The differential fluxes from HZETRN were generally well-correlated with balloon-based measurements; the median relative model difference across the entire dataset was determined to be 30%. The distribution of model uncertainties, however, revealed that the range of errors was relatively broad, with approximately 30% of the uncertainties exceeding ± 40%. The distribution also indicated that HZETRN systematically under-predicts the measurement dataset as a whole, with approximately 80% of the relative uncertainties having negative values. Instances of systematic bias for subsets of the data were also observed, including a significant underestimation of alpha particles and protons for energies below 2.5 GeV/u. Muons were found to be systematically over-predicted at atmospheric depths deeper than 50 g/cm2 but under-predicted for shallower depths. Furthermore, a systematic under-prediction of alpha particles and protons was observed below the geomagnetic cutoff, suggesting that

  7. Phase II Contaminant Transport Parameters for the Groundwater Flow and Contaminant Transport Model of Corrective Action Unit 98: Frenchman Flat, Nye County, Nevada, Rev. No.: 0

    Energy Technology Data Exchange (ETDEWEB)

    DeNovio, Nicole M.; Bryant, Nathan; King, Chrissi B.; Bhark, Eric; Drellack, Sigmund L.; Pickens, John F.; Farnham, Irene; Brooks, Keely M.; Reimus, Paul; Aly, Alaa

    2005-04-01

    This report documents pertinent transport data and data analyses as part of the Phase II Corrective Action Investigation (CAI) for Frenchman Flat (FF) Corrective Action Unit (CAU) 98. The purpose of this data compilation and related analyses is to provide the primary reference to support parameterization of the Phase II FF CAU transport model.

  8. Dynamics of Coupled Contaminant and Microbial Transport in Heterogeneous Porous Media: Purdue Component

    Energy Technology Data Exchange (ETDEWEB)

    Cushman, J.H.; Madilyn Fletcher

    2000-06-01

    Dynamic microbial attachment/detachment occurs in subsurface systems in response to changing environmental conditions caused by contaminant movement and degradation. Understanding the environmental conditions and mechanisms by which anaerobic bacteria partition between aqueous and solid phases is a critical requirement for designing and evaluating in situ bioremediation efforts. This interdisciplinary research project, of which we report only the Purdue contribution, provides fundamental information on the attachment/detachment dynamics of bacteria in heterogeneous porous media. Fundamental results from the Purdue collaboration are: (a) development of a matched-index method for obtaining 3-D Lagrangian trajectories of microbial sized particles transporting within porous media or microflow cells, (b) application of advanced numerical methods to optimally design a microflow cell for studying anaerobic bacterial attachment/detachment phenomena, (c) development of two types of models for simulating bacterial movement and attachment/detachment in microflow cells and natural porous media, (d) application of stochastic analysis to upscale pore scale microbial attachment/detachment models to natural heterogeneous porous media, and (e) evaluation of the role nonlocality plays in microbial dynamics in heterogeneous porous media

  9. Dynamics of Coupled Contaminant and Microbial Transport in Heterogeneous Porous Media: Purdue Component. Final report

    International Nuclear Information System (INIS)

    Cushman, J.H.

    2000-01-01

    Dynamic microbial attachment/detachment occurs in subsurface systems in response to changing environmental conditions caused by contaminant movement and degradation. Understanding the environmental conditions and mechanisms by which anaerobic bacteria partition between aqueous and solid phases is a critical requirement for designing and evaluating in situ bioremediation efforts. This interdisciplinary research project, of which we report only the Purdue contribution, provides fundamental information on the attachment/detachment dynamics of bacteria in heterogeneous porous media. Fundamental results from the Purdue collaboration are: (a) development of a matched-index method for obtaining 3-D Lagrangian trajectories of microbial sized particles transporting within porous media or microflow cells, (b) application of advanced numerical methods to optimally design a microflow cell for studying anaerobic bacterial attachment/detachment phenomena, (c) development of two types of models for simulating bacterial movement and attachment/detachment in microflow cells and natural porous media, (d) application of stochastic analysis to upscale pore scale microbial attachment/detachment models to natural heterogeneous porous media, and (e) evaluation of the role nonlocality plays in microbial dynamics in heterogeneous porous media

  10. Leaching and soil/groundwater transport of contaminants from coal combustion residues

    International Nuclear Information System (INIS)

    Hjelmar, O.; Hansen, E.A.; Larsen, F.; Thomassen, H.

    1992-01-01

    In this project the results of accelerated laboratory leaching tests on coal fly ash and flue gas desulfurization (FGD) products from the spray dryer absorption process (SDA) were evaluated by comparison to the results of large scale lysimeter leaching tests on the same residues. The mobility of chromium and molybdenum - two of the kev contaminants of coal combustion residue leachates - in various typical soil types was investigated by batch and column methods in the laboratory. Some of the results were confirmed by field observations at an old coal fly ash disposal site and by a lysimeter attenuation test with coal fly ash leachate on a clayed till. A large number of groundwater transport models and geochemical models were reviewed, and two of the models (Gove-Stollenwerk and CHMTRNS) were modified and adjusted and used to simulate column attenuation tests performed in the laboratory. One of the models (Grove-Stollenwerk) was used to illustrate a recommended method of environmental impact assessment, using lysimeter leaching data and laboratory column attenuation data to describe the emission and migration of Mo from a coal fly ash disposal site

  11. Dynamics of Coupled Contaminant and Microbial Transport in Heterogeneous Porous Media: Purdue Component

    Energy Technology Data Exchange (ETDEWEB)

    Cushman, J.H.

    2000-06-01

    Dynamic microbial attachment/detachment occurs in subsurface systems in response to changing environmental conditions caused by contaminant movement and degradation. Understanding the environmental conditions and mechanisms by which anaerobic bacteria partition between aqueous and solid phases is a critical requirement for designing and evaluating in situ bioremediation efforts. This interdisciplinary research project, of which we report only the Purdue contribution, provides fundamental information on the attachment/detachment dynamics of bacteria in heterogeneous porous media. Fundamental results from the Purdue collaboration are: (a) development of a matched-index method for obtaining 3-D Lagrangian trajectories of microbial sized particles transporting within porous media or microflow cells, (b) application of advanced numerical methods to optimally design a microflow cell for studying anaerobic bacterial attachment/detachment phenomena, (c) development of two types of models for simulating bacterial movement and attachment/detachment in microflow cells and natural porous media, (d) application of stochastic analysis to upscale pore scale microbial attachment/detachment models to natural heterogeneous porous media, and (e) evaluation of the role nonlocality plays in microbial dynamics in heterogeneous porous media.

  12. Preliminary assessment for dust contamination of ITER In-Vessel Transporter

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Makiko, E-mail: saito.makiko@jaea.go.jp [Japan Atomic Energy Agency, Fusion Research and Development Directorate, Naka, Ibaraki-ken 311-0193 (Japan); Ueno, Kenichi; Maruyama, Takahito; Murakami, Shin; Takeda, Nobukazu; Kakudate, Satoshi [Japan Atomic Energy Agency, Fusion Research and Development Directorate, Naka, Ibaraki-ken 311-0193 (Japan); Nakahira, Masataka; Tesini, Alessandro [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance (France)

    2014-10-15

    Highlights: •To assess the exposure to the maintenance workers, we calculated the effective dose rate. •To reduce the effective dose rate, the IVT was decontaminated and underwent a design change. •The effective dose rate at each maintenance point was also calculated. -- Abstract: After plasma operations of ITER, radioactive dust will have accumulated in the vacuum vessel (VV). The In-Vessel Transporter (IVT) will be introduced into the VV to remove the shield blanket modules for maintenance or replacement and later reinstall them. The IVT itself also needs to undergo regular maintenance in the Hot Cell Facility (HCF). It is assumed that maintenance workers will be exposed to radioactive dust that has adhered to the surfaces of the IVT. In this study, the areas of the IVT that may be contaminated by dust are evaluated to assess the level of exposure to workers during maintenance work in the HCF. Decontamination processes for the IVT, such as a combination of vacuuming and brushing, were investigated and the dose rate after these processes was evaluated. Even though dust was removed from surfaces where decontamination was possible, the dose rate was very high at some assessment points. To decrease the dose rate in accordance with ALARA policy, a decontamination plan and a maintenance plan, which includes the removal of dust, a radiation shield system, and a reduction in working time are proposed.

  13. The role of rivers in transporting organic contaminants in the marine environment of Greece

    Science.gov (United States)

    Hatzianestis, Ioannis

    2013-04-01

    The study of trace organic contaminants in coastal marine environments and especially in estuarine systems is of great importance, since these areas, being biologically productive and receiving considerable pollutant inputs from land-based sources via river runoff, act as a transit zone in which contaminants are transported to the sea. The aim of this work is to identify the significance of estuarine export of organic pollution in the marine environment of Greece. For this reason, the distribution, composition and sources of hydrocarbon mixtures were investigated in sediments collected from eight major Greek estuarine systems, by using a molecular marker approach and several diagnostic criteria and indices. Surface sediment samples were collected from the estuaries of five rivers in Northern Greece flowing into Aegean sea (Axios, Aliakmonas, Strymon, Nestos, Evros), one river in Central Greece (Asopos) also flowing into Aegean Sea and two rivers in Western Greece flowing into Ionian sea (Acheloos, Acherontas). The highest aliphatic hydrocarbon concentrations (>100 μg/g), indicative of petroleum pollution, were recorded in Asopos estruaries, followed by Aliakmonas, Axios, Strymon and Evros estuaries (50-100 μg/g). On the contrary, in Nestos delta, as well as in Acheloos and Acherontas estuaries, hydrocarbon values were found low and similar to those measured in open sea (marine environment. The unresolved complex mixture (UCM) was the main component of the aliphatic fraction in most cases demonstrating some petroleum inputs in all areas, but high values of the ratio unresolved to resolved compounds (U/R), which are clearly indicative of petroleum residues, were measured only in Asopos, Axios and Evros estuary (U/R: 5.1-10.4). The n-alkane distribution was generally similar with that of total aliphatics. The high molecular weight n-alkanes (>C23) predominated in most cases, showing an important odd/even carbon number preference (mean CPI values above 5) which is

  14. 134Cs-transport in an experimental ecological system

    International Nuclear Information System (INIS)

    Mocsy, Ildiko; Uray, Ildiko; Salagean, Stefania

    1986-01-01

    An experimental aquatic ecosystem was developed consisting of river water, slurry, algae and crustaceans. The change of the cesium concentration factor (F c ) of two alga species were measured using 20 Bq/ml of 134 CsCl. Measurements were performed in the 6th, 12th, 24th, 48th and 72nd hour after irradiation. F c in crustaceans was found to be 1300 in the 12th hr, then decreased rapidly down to 275. The temporal dependence of cesium accumulation in slurry increased consistently. It was found that algae accumulated cesium variously. Owing to its high accumulation, Cladophora glomerata can be used as a biological indicator of cesium concentration in surface waters. (K.I.)

  15. Contaminant Transport Parameters for the Groundwater Flow and Contaminant Transport Model of Corrective Action Units 101 and 102: Central and Western Pahute Mesa, Nye County, Nevada, Revision 0

    Energy Technology Data Exchange (ETDEWEB)

    Drici, Warda [International Technologies Corporation, Las Vegas, NV (United States)

    2003-08-01

    This report documents the analysis of the available transport parameter data conducted in support of the development of a Corrective Action Unit (CAU) groundwater flow model for Central and Western Pahute Mesa: CAUs 101 and 102.

  16. Research on establishment of emergency transportation of heavy-injured and radiation-exposed and contaminated patients. Toward rapid, contamination-preventive and safe land and air transportion

    International Nuclear Information System (INIS)

    Haraguchi, Yoshikura; Tomoyasu, Y.; Yamamoto, Yasuhiro; Ishihara, Toru

    2004-01-01

    The authors has continued researches on countermeasures against various disasters including nuclear or radiation accident. Present paper deals with the following items; (1) Significance of preparation of a manual on countermeasures against disasters in relation to medical drills, (2) Status and prospects of disaster simulations and disaster drills, (3) Promotion and education on medical knowledge when nuclear disasters occur, (4) Network system study of broad area medicines throughout the country. (5) Study on how to approach mental an psychological cares, (6) Specialities of radioactive contamination in the general contamination of NBC (Nuclear, Biological and Chemical) disasters, (7) New concept and preparation of triage tags, and (8) Queueing theory application to many patients in a hospital. (H. Yokoo)

  17. Experimental results on transport and focusing of laser accelerated protons

    Energy Technology Data Exchange (ETDEWEB)

    Busold, Simon; Deppert, Oliver; Roth, Markus [TU Darmstadt, IKP, Schlossgartenstr. 9, 64289 Darmstadt (Germany); Schumacher, Dennis; Blazevic, Abel; Zielbauer, Bernhard; Hofmann, Ingo; Bagnoud, Vincent [GSI Helmholtzzentrum fuer Schwerionenforschung, Planckstr. 1, 64291 Darmstadt (Germany); Brabetz, Christian; Al-Omari, Husam [JWG Universitaet Frankfurt, IAP, Max von Laue Str. 1, 60438 Frankfurt am Main (Germany); Joost, Martin; Kroll, Florian; Cowan, Tom [Helmholtzzentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328 Dresden (Germany); Collaboration: LIGHT-Collaboration

    2013-07-01

    Irradiation of thin foils with high-intensity laser pulses became a reliable tool during the last decade for producing high-intensity proton bunches in about a pico-second from a sub-millimeter source. However, the energy distribution is of an exponential shape with a currently achievable cut-off energy <100 MeV (TNSA mechanism) and the beam is highly divergent with an energy-dependent envelope-divergence of up to 60 deg. Thus, for most applications it is necessary to be able to capture and control these protons as well as select a specific energy. In the frame of the LIGHT collaboration, experimental studies were done at the PHELIX laser at GSI Darmstadt using a pulsed high-field solenoid and alternatively a permanent magnet quadrupole triplet in order to match the beam for injection into a RF cavity. The beam was characterized at several distances after the source and the results are compared to particle tracking simulations.

  18. Microbial responses to polycyclic aromatic hydrocarbon contamination in temporary river sediments: Experimental insights.

    Science.gov (United States)

    Zoppini, Annamaria; Ademollo, Nicoletta; Amalfitano, Stefano; Capri, Silvio; Casella, Patrizia; Fazi, Stefano; Marxsen, Juergen; Patrolecco, Luisa

    2016-01-15

    Temporary rivers are characterized by dry-wet phases and represent an important water resource in semi-arid regions worldwide. The fate and effect of contaminants have not been firmly established in temporary rivers such as in other aquatic environments. In this study, we assessed the effects of sediment amendment with Polycyclic Aromatic Hydrocarbons (PAHs) on benthic microbial communities. Experimental microcosms containing natural (Control) and amended sediments (2 and 20 mg PAHs kg(-1) were incubated for 28 days. The PAH concentrations in sediments were monitored weekly together with microbial community structural (biomass and phylogenetic composition by TGGE and CARD-FISH) and functional parameters (ATP concentration, community respiration rate, bacterial carbon production rate, extracellular enzyme activities). The concentration of the PAH isomers did not change significantly with the exception of phenanthrene. No changes were observed in the TGGE profiles, whereas the occurrence of Alpha- and Beta-Proteobacteria was significantly affected by the treatments. In the amended sediments, the rates of carbon production were stimulated together with aminopeptidase enzyme activity. The community respiration rates showed values significantly lower than the Control after 1 day from the amendment then recovering the Control values during the incubation. A negative trend between the respiration rates and ATP concentration was observed only in the amended sediments. This result indicates a potential toxic effect on the oxidative phosphorylation processes. The impoverishment of the energetic resources that follows the PAH impact may act as a domino on the flux of energy from prokaryotes to the upper level of the trophic chain, with the potential to alter the temporary river functioning.

  19. Zero-tension lysimeters: An improved design to monitor colloid-facilitated contaminant transport in the vadose zone

    International Nuclear Information System (INIS)

    Thompson, M.L.; Scharf, R.L.; Shang, C.

    1995-01-01

    There is increasing evidence that mobile colloids facilitate the long-distance transport of contaminants. The mobility of fine particles and macromolecules has been linked to the movement of actinides, organic contaminants, and heavy metals through soil. Direct evidence for colloid mobility includes the presence of humic materials in deep aquifers as well as coatings of accumulated clay, organic matter, or sesquioxides on particle or aggregate surfaces in subsoil horizons of many soils. The potential for colloid-facilitated transport of contaminants from hazardous-waste sites requires adequate monitoring before, during, and after in-situ remediation treatments. Zero-tension lysimeters (ZTLs) are especially appropriate for sampling water as it moves through saturated soil, although some unsaturated flow events may be sampled as well. Because no ceramic barrier or fiberglass wick is involved to maintain tension on the water (as is the case with other lysimeters), particles suspended in the water as well as dissolved species may be sampled with ZTLs. In this report, a ZTL design is proposed that is more suitable for monitoring colloid-facilitated contaminant migration. The improved design consists of a cylinder made of polycarbonate or polytetrafluoroethylene (PTFE) that is placed below undisturbed soil material. In many soils, a hydraulically powered tube may be used to extract an undisturbed core of soil before placement of the lysimeter. In those cases, the design has significant advantages over conventional designs with respect to simplicity and speed of installation. Therefore, it will allow colloid-facilitated transport of contaminants to be monitored at more locations at a given site

  20. Ammonia gas transport and reactions in unsaturated sediments: Implications for use as an amendment to immobilize inorganic contaminants

    International Nuclear Information System (INIS)

    Zhong, L.; Szecsody, J.E.; Truex, M.J.; Williams, M.D.; Liu, Y.

    2015-01-01

    Highlights: • Ammonia transport can be predicted from gas movement and equilibrium partitioning. • Ammonia diffusion rate in unsaturated sediment is a function of water contents. • High pH induced by ammonia causes mineral dissolution and sequential precipitation. • Ammonia treatment effectively immobilized uranium from contaminated sediments. - Abstract: Use of gas-phase amendments for in situ remediation of inorganic contaminants in unsaturated sediments of the vadose zone may be advantageous, but there has been limited development and testing of gas remediation technologies. Treatment with ammonia gas has a potential for use in treating inorganic contaminants (such as uranium) because it induces a high pore-water pH, causing mineral dissolution and subsequent formation of stable precipitates that decrease the mobility of some contaminants. For field application of this treatment, further knowledge of ammonia transport in porous media and the geochemical reactions induced by ammonia treatment is needed. Laboratory studies were conducted to support calculations needed for field treatment design, to quantify advective and diffusive ammonia transport in unsaturated sediments, to evaluate inter-phase (gas/sediment/pore water) reactions, and to study reaction-induced pore-water chemistry changes as a function of ammonia delivery conditions, such as flow rate, gas concentration, and water content. Uranium-contaminated sediment was treated with ammonia gas to demonstrate U immobilization. Ammonia gas quickly partitions into sediment pore water and increases the pH up to 13.2. Injected ammonia gas advection front movement can be reasonably predicted by gas flow rate and equilibrium partitioning. The ammonia gas diffusion rate is a function of the water content in the sediment. Sodium, aluminum, and silica pore-water concentrations increase upon exposure to ammonia and then decline as aluminosilicates precipitate when the pH declines due to buffering. Up to 85% of

  1. An Integrated Experimental-Modelling Procedure Applied to the Design of a Field Scale Goethite Nanoparticle Injection for the Remediation of Contaminated Sites

    Science.gov (United States)

    Bianco, C.; Tosco, T.; Sethi, R.

    2017-12-01

    Nanoremediation is a promising in-situ technology for the reclamation of contaminated aquifers. It consists in the subsurface injection of a reactive colloidal suspension for the in-situ treatment of pollutants. The overall success of this technology at the field scale is strictly related to the achievement of an effective and efficient emplacement of the nanoparticles (NP) inside the contaminated area. Mathematical models can be used to support the design of nanotechnology-based remediation by effectively assessing the expected NP mobility at the field scale. Several analytical and numerical tools have been developed in recent years to model the transport of NPs in simplified geometry and boundary conditions. The numerical tool MNMs was developed by the authors of this work to simulate colloidal transport in 1D Cartesian and radial coordinates. A new modelling tool, MNM3D (Micro and Nanoparticle transport Model in 3D geometries), was also proposed for the simulation of injection and transport of NP suspensions in generic complex scenarios. MNM3D accounts for the simultaneous dependency of NP transport on water ionic strength and velocity. The software was developed to predict the NP mobility at different stages of a nanoremediation application, from the design stage to the prediction of the long-term fate after injection. In this work an integrated experimental-modelling procedure is applied to support the design of a field scale injection of goethite NPs carried out in the framework of the H2020 European project Reground. Column tests are performed at different injection flowrates using natural sand collected at the contaminated site as porous medium. The tests are interpreted using MNMs to characterize the NP mobility and derive the constitutive equations describing the suspension behavior in the natural porous medium. MNM3D is then used to predict NP behavior during the field scale injection and to assess the long-term mobility of the injected slurry. Finally

  2. Auxiliary analyses in support of performance assessment of a hypothetical low-level waste facility: Two-phase flow and contaminant transport in unsaturated soils with application to low-level radioactive waste disposal. Volume 2

    International Nuclear Information System (INIS)

    Binning, P.; Celia, M.A.; Johnson, J.C.

    1995-05-01

    A numerical model of multiphase air-water flow and contaminant transport in the unsaturated zone is presented. The multiphase flow equations are solved using the two-pressure, mixed form of the equations with a modified Picard linearization of the equations and a finite element spatial approximation. A volatile contaminant is assumed to be transported in either phase, or in both phases simultaneously. The contaminant partitions between phases with an equilibrium distribution given by Henry's Law or via kinetic mass transfer. The transport equations are solved using a Galerkin finite element method with reduced integration to lump the resultant matrices. The numerical model is applied to published experimental studies to examine the behavior of the air phase and associated contaminant movement under water infiltration. The model is also used to evaluate a hypothetical design for a low-level radioactive waste disposal facility. The model has been developed in both one and two dimensions; documentation and computer codes are available for the one-dimensional flow and transport model

  3. Classification of the Group Invariant Solutions for Contaminant Transport in Saturated Soils under Radial Uniform Water Flows

    Directory of Open Access Journals (Sweden)

    M. M. Potsane

    2014-01-01

    Full Text Available The transport of chemicals through soils to the groundwater or precipitation at the soils surfaces leads to degradation of these resources. Serious consequences may be suffered in the long run. In this paper, we consider macroscopic deterministic models describing contaminant transport in saturated soils under uniform radial water flow backgrounds. The arising convection-dispersion equation given in terms of the stream functions is analyzed using classical Lie point symmetries. A number of exotic Lie point symmetries are admitted. Group invariant solutions are classified according to the elements of the one-dimensional optimal systems. We analyzed the group invariant solutions which satisfy the physical boundary conditions.

  4. Measuring and predicting the transport of actinides and fission product contaminants in unsaturated prairie soil

    Science.gov (United States)

    Sims, D. J.

    Soil samples have been taken in 2001 from the area of a 1951 release from an underground storage tank of 6.7 L of an aqueous solution of irradiated uranium (360 GBq). A simulation of the dispersion of the actinides and fission products was conducted in the laboratory using irradiated natural uranium, non-irradiated natural uranium and metal standards dissolved in acidic aqueous solutions and added to soil columns containing uncontaminated prairie soil. The lab soil columns were allowed 12 to 14 months for contaminant transport. Soil samples were analyzed using gamma-ray spectroscopy, neutron activation analysis (NAA) and liquid scintillation counting (LSC) to determine the elemental concentrations of U, Cs and Sr. Diffusion coefficients from the 50 year soil samples and the lab soil samples were determined. The measured diffusion coefficients from the field samples were 3.0 x 10-4 cm2 s-1 (Cs-137), 1.8 x 10-5 cm2 s-1 (U-238) and 2.6 x 10-3 cm2 s-1 (Sr-90) and the values determined from lab simulation were 5 x 10-6 cm 2 s-1 (Cs-137), 3 x 10-5 cm2 s-1 (U-238) and 1.9 x 10-5 cm 2 s-1 (Sr-90). The differences between the sets of diffusion coefficients can be attributed to differences in retardation effects, weather effects and changes in the soil characteristics when transporting, such as porosity. The analytical work showed that Cs-137 content of soil can be determined effectively using gamma-ray spectroscopy; U-238 content can be measured using NAA; and Sr-90 content can be measured using LSC. For non- and low-radioactive species, it was shown that both flame atomic absorption spectrometry (FAAS) and inductively-coupled plasma-mass spectrometry (ICP-MS) gave comparable results for Sr, Cs and Sm, with the average values ranging from 0.5 to 4.5 ppm of each other. The U-238 content results from NAA and from ICP-MS showed general agreement with an average difference of 81.3 ppm on samples having concentrations up to 988.2 ppm. The difference may have been due to matrix

  5. The deterioration during transport and storage of tomato fruits by microorganisms contaminating the surface and latent infected tissue

    OpenAIRE

    河野, 又四; 寺下, 隆夫

    1988-01-01

    [Author abstract]Deterioration during transport and storage of tomato fruits is generally thought to be caused by microorganisms contaminating the surface and latent infected tissue of apparently healthy fruit. Counts of viable airborne microorganisms showed that there were more in plastic greenhouses than in open culure of tomatoes. Altemaria, Aspergillus niger, Asp. oryzae, Cladosporium, Fusarium, Mucor, Penicillium, Trichoderma, Trichothecium, Bacillus, Erwinia and Pseudomonas were among t...

  6. Microbial diversity in contaminated soils along the T22 trench of the Chernobyl experimental platform

    Energy Technology Data Exchange (ETDEWEB)

    Chapon, Virginie [CEA, DSV, IBEB, SBVME, LIPM, F-13108 Saint-Paul-lez-Durance (France); CNRS, UMR 6191, F-13108 Saint-Paul-lez-Durance (France); Universite d' Aix-Marseille, F-13108 Saint-Paul-lez-Durance (France); Piette, Laurie [CEA, DSV, IBEB, SBVME, LIPM, F-13108 Saint-Paul-lez-Durance (France); CNRS, UMR 6191, F-13108 Saint-Paul-lez-Durance (France); Universite d' Aix-Marseille, F-13108 Saint-Paul-lez-Durance (France); Vesvres, Marie-Helene [Universite de Bordeaux 1/CNRS-IN2P3, UMR 5797, CENBG, POB 120, F-33175 Gradignan cedex (France); Coppin, Frederic [IRSN, DEI/SECRE/LRE-Bat 186, B.P.3, Cadarache Center, F-13115 Saint-Paul-lez-Durance cedex (France); Marrec, Claire Le [ISVV, UMR 1219, Institut Polytechnique de Bordeaux/INRA, POB 50008, F-33882 Villenave d' Ornon (France); Christen, Richard [Universite de Nice-Sophia-Antipolis, Centre de Biochimie, Parc Valrose, F-06108 Nice (France); CNRS, UMR 6543, Centre de Biochimie, Parc Valrose, F-06108 Nice (France); Theodorakopoulos, Nicolas [CEA, DSV, IBEB, SBVME, LIPM, F-13108 Saint-Paul-lez-Durance (France); CNRS, UMR 6191, F-13108 Saint-Paul-lez-Durance (France); Universite d' Aix-Marseille, F-13108 Saint-Paul-lez-Durance (France); Universite de Bordeaux 1/CNRS-IN2P3, UMR 5797, CENBG, POB 120, F-33175 Gradignan cedex (France); IRSN, DEI/SECRE/LRE-Bat 186, B.P.3, Cadarache Center, F-13115 Saint-Paul-lez-Durance cedex (France); Fevrier, Laureline [IRSN, DEI/SECRE/LRE-Bat 186, B.P.3, Cadarache Center, F-13115 Saint-Paul-lez-Durance cedex (France); others, and

    2012-07-15

    The diversity of bacterial communities exposed to radioactive contamination in Chernobyl soils was examined by a combination of molecular and culture-based approaches. A set of six radioactive soil samples, exhibiting high levels of {sup 137}Cs contamination, were collected from the T22 trench. Three samples were also collected in nearby soils with low contamination. Complex bacterial community structures were observed in both highly and weakly contaminated samples, using a molecular approach targeting the 16S rRNA gene. However, the presence of specific populations within samples from highly contaminated soils could not be revealed by statistical analysis of the DGGE profiles. More than 200 culturable isolates, representative of dominant morphotypes, were grouped into 83 Operational Taxonomic Units (OTUs) and affiliated to Firmicutes, Actinobacteria, Alpha-, Beta-, Gamma-Proteobacteria and Bacteroiedetes. No specific pattern linked to contamination was observed for these culturable bacteria. The results show that both highly and weakly contaminated soils host a wide diversity of bacteria, suggesting that long term exposure to radionuclides does not lead to the extinction of bacterial diversity.

  7. Microbial diversity in contaminated soils along the T22 trench of the Chernobyl experimental platform

    International Nuclear Information System (INIS)

    Chapon, Virginie; Piette, Laurie; Vesvres, Marie-Hélène; Coppin, Frédéric; Marrec, Claire Le; Christen, Richard; Theodorakopoulos, Nicolas; Février, Laureline

    2012-01-01

    The diversity of bacterial communities exposed to radioactive contamination in Chernobyl soils was examined by a combination of molecular and culture-based approaches. A set of six radioactive soil samples, exhibiting high levels of 137 Cs contamination, were collected from the T22 trench. Three samples were also collected in nearby soils with low contamination. Complex bacterial community structures were observed in both highly and weakly contaminated samples, using a molecular approach targeting the 16S rRNA gene. However, the presence of specific populations within samples from highly contaminated soils could not be revealed by statistical analysis of the DGGE profiles. More than 200 culturable isolates, representative of dominant morphotypes, were grouped into 83 Operational Taxonomic Units (OTUs) and affiliated to Firmicutes, Actinobacteria, Alpha-, Beta-, Gamma-Proteobacteria and Bacteroïdetes. No specific pattern linked to contamination was observed for these culturable bacteria. The results show that both highly and weakly contaminated soils host a wide diversity of bacteria, suggesting that long term exposure to radionuclides does not lead to the extinction of bacterial diversity.

  8. A novel modeling tool with multi-stressor functionality for organic contaminant transport and fate in the Baltic Sea

    Energy Technology Data Exchange (ETDEWEB)

    Undeman, E., E-mail: emma.undeman@itm.su.se [Baltic Nest Institute, Baltic Sea Centre, Stockholm University, 10691 Stockholm (Sweden); Department of Applied Environmental Science, Stockholm University, 11418 Stockholm (Sweden); Gustafsson, E., E-mail: erik.gustafsson@su.se [Baltic Nest Institute, Baltic Sea Centre, Stockholm University, 10691 Stockholm (Sweden); Gustafsson, B.G., E-mail: bo.gustafsson@su.se [Baltic Nest Institute, Baltic Sea Centre, Stockholm University, 10691 Stockholm (Sweden)

    2014-11-01

    The coupled physical–biogeochemical model BALTSEM, previously used to assess nutrient/carbon cycles and eutrophication in the Baltic Sea, has been expanded to include algorithms for calculations of organic contaminant environmental transport and fate. This novel model version (BALTSEM-POP) is evaluated for polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) and hexachlorobenzene (HCB) in Baltic Sea surface water and sediment. Modeled dissolved concentrations are usually within a factor of 2–4 of observed concentrations, however with larger deviations for furans. Calculated concentrations in particulate organic matter are less accurate (within factors of 1–700), likely due to errors in estimated pelagic biomass, particulate matter–water partitioning, and large natural variability in field data. Concentrations in sediments are usually predicted within a factor of 6. The good performance of the model illustrates its usefulness for exploration of contaminant fate in response to variations in nutrient input and climatic conditions in the Baltic Sea marine environment. - Highlights: • A new model for organic chemical transport and fate in the Baltic Sea is presented. • Physical and biogeochemical processes are linked to organic contaminant transport. • The model is evaluated for PCBs, HCB and PCDD/Fs. • The model can predict dissolved concentrations within a factor of ca 2–4. • Predictions for concentrations in particulate matter and sediment are less accurate.

  9. Determinación experimental de los coeficientes locales de transporte de humedad en almacenes soterrados. // Experimental determination of local humidity transport coefficients in underground warehouses.

    Directory of Open Access Journals (Sweden)

    Ma. D. Andrade Gregori

    2006-05-01

    Full Text Available En el trabajo se fundamentan los mecanismos de transporte de humedad que tienen lugar en almacenes soterrados dadas lascaracterísticas climáticas y geohidrològicas de Cuba. Se establece una analogía con la ley de Fick y se propone un modeloteórico que describe este mecanismo de transporte hacia las cavidades. Se determinó experimentalmente los coeficienteslocales de transporte de humedad para diferentes tipos de recubrimiento en paredes y diferentes formas geométricas de losalmacenes.Palabras claves: Almacenes, soterrado, humedad, conservación, coeficientes._______________________________________________________________________________Abstract.In this paper the mechanisms of humidity transport are explained. These mechanisms have place in underground warehousesaccording to the climatic and geohydrological characteristics of Cuba. An analogy with the Fick´s law is stated and it intends atheoretical model that describes this mechanism of transport toward the cavities. It was determined the local coefficients oftransport of humidity experimentally for different recover types in walls and different geometric forms of the warehouses.Key words: Store, buried, humidity, conservation, and coefficients.

  10. Experimentally determined distribution of granular-flow characteristics in collisional bed load transport

    Directory of Open Access Journals (Sweden)

    Matoušek Václav

    2018-01-01

    Full Text Available A series of laboratory experiments on turbulent open-channel two-phase flow in a form of intense bed load transport is reported. Measurements in a laboratory tilting flume included camera based imaging techniques to identify the structure of the flow at the local level. Obtained experimental distributions of two-phase flow related parameters - granular velocity, concentration, and temperature - across a collisional transport layer are discussed. The results are analysed together with additional measured quantities (discharges of mixture and grains, flow depth, bed slope etc. Our major goal is to evaluate the distribution of granular stresses across the transport layer with a special attention paid to the interface between the transport layer and the bed. Furthermore, comparisons are discussed between the experimental results and predictions produced by suitable kinetic-theory based models.

  11. Colloid facilitated transport in fractured rocks: parameter estimation and comparison with experimental data

    International Nuclear Information System (INIS)

    Viswanthan, H.S.; Wolfsberg, A.V.; Reimus, P.W.; Ware, D.; Lu, G.

    2003-01-01

    Colloid-facilitated migration of plutonium in fractured rock has been implicated in both field and laboratory studies. Other reactive radionuclides may also experience enhanced mobility due to groundwater colloids. Model prediction of this process is necessary for assessment of contaminant boundaries in systems for which radionuclides are already in the groundwater and for performance assessment of potential repositories for radioactive waste. Therefore, a reactive transport model is developed and parameterized using results from controlled laboratory fracture column experiments. Silica, montmorillonite and clinoptilolite colloids are used in the experiments along with plutonium and Tritium. The goal of the numerical model is to identify and parameterize the physical and chemical processes that affect the colloid-facilitated transport of plutonium in the fractures. The parameters used in this model are similar in form to those that might be used in a field-scale transport model

  12. Absorption and transport of radioactive 57Co-vitamin B12 in experimental giardiasis in rats

    International Nuclear Information System (INIS)

    Deka, N.C.; Sehgal, A.K.; Chnuttani, P.N.

    1981-01-01

    Giardiasis was produced in weanling albino rats by feeding suspension of Giardia lamblia cysts isolated from human stool. Experiments were carried out to assess the absorption and transport through intestinal wall of 57 Co-vitamin B 12 in these rats. The results showed a significant impairment of the absorption of the vitamin in the rats with experimental giardiasis. However, the transport of the vitamin B 12 was unimpaired. (author)

  13. Sodium cleaning from sodium contaminated components and operation for experimental equipment

    Energy Technology Data Exchange (ETDEWEB)

    Kim, B. H.; Kim, J. M.; Kim, T. J.; Nam, H. Y.; Jeong, J. Y.; Choi, B. H.; Choi, J. H

    2007-11-15

    An objective of washing technology development for sodium contaminated equipment is to clean and reuse safely and effectively the used equipment through a washing and maintenance, and recovery of the sodium wastes generated during washing.

  14. Development of RWHet to Simulate Contaminant Transport in Fractured Porous Media

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yong; LaBolle, Eric; Reeves, Donald M; Russell, Charles

    2012-07-01

    Accurate simulation of matrix diffusion in regional-scale dual-porosity and dual-permeability media is a critical issue for the DOE Underground Test Area (UGTA) program, given the prevalence of fractured geologic media on the Nevada National Security Site (NNSS). Contaminant transport through regional-scale fractured media is typically quantified by particle-tracking based Lagrangian solvers through the inclusion of dual-domain mass transfer algorithms that probabilistically determine particle transfer between fractures and unfractured matrix blocks. UGTA applications include a wide variety of fracture aperture and spacing, effective diffusion coefficients ranging four orders of magnitude, and extreme end member retardation values. This report incorporates the current dual-domain mass transfer algorithms into the well-known particle tracking code RWHet [LaBolle, 2006], and then tests and evaluates the updated code. We also develop and test a direct numerical simulation (DNS) approach to replace the classical transfer probability method in characterizing particle dynamics across the fracture/matrix interface. The final goal of this work is to implement the algorithm identified as most efficient and effective into RWHet, so that an accurate and computationally efficient software suite can be built for dual-porosity/dual-permeability applications. RWHet is a mature Lagrangian transport simulator with a substantial user-base that has undergone significant development and model validation. In this report, we also substantially tested the capability of RWHet in simulating passive and reactive tracer transport through regional-scale, heterogeneous media. Four dual-domain mass transfer methodologies were considered in this work. We first developed the empirical transfer probability approach proposed by Liu et al. [2000], and coded it into RWHet. The particle transfer probability from one continuum to the other is proportional to the ratio of the mass entering the other

  15. Experimental studies of influence of different electrodes on bridging in contaminated transformer oil

    OpenAIRE

    Mahmud, S.; Chen, G.; Golosnoy, I.O.; Wilson, G.; Jarman, P.

    2015-01-01

    Contaminated transformer oil has been tested under non uniform electric fields and the effect of different electrode systems presented in this paper. Three different electric fields were examined i.e. DC, AC and DC biased AC. These experiments revealed that with all the different electrodes arrangements, contaminated particles always formed bridges between electrodes under DC electric field. The bridges were thicker and more particles were attracted with more uniform electric field (spherical...

  16. Current transport modeling and experimental study of THz room temperature ballistic deflection transistors

    Energy Technology Data Exchange (ETDEWEB)

    Kaushal, Vikas; Margala, Martin [Department of Electrical and Computer Engineering, University of Massachusetts Lowell, MA, 01854 (United States); Yu Qiaoyan; Ampadu, Paul; Guarino, Gregg; Sobolewski, Roman, E-mail: vikas_kaushal@student.uml.ed [Department of Electrical and Computer Engineering, University of Rochester, NY, 14627 (United States)

    2009-11-15

    In this paper, two different theoretical models, Comsol Multiphysics{sup TM} (a Finite Element Analysis tool), and a field solver Atlas/Blaze from Silvaco, are compared qualitatively to study the effect of the deflector position, its size and electric field on the charge transport and its distribution along the channel, resulting in current outputs and leakages in ballistic deflection transistors (BDT). Silvaco simulations and experimental results were then used to study the lateral charge transport as a result of variation in electric field distribution, which controls the charge current along the channel in BDT. The electric field dependence of gain is also studied with experimental and theoretical results.

  17. Current transport modeling and experimental study of THz room temperature ballistic deflection transistors

    International Nuclear Information System (INIS)

    Kaushal, Vikas; Margala, Martin; Yu Qiaoyan; Ampadu, Paul; Guarino, Gregg; Sobolewski, Roman

    2009-01-01

    In this paper, two different theoretical models, Comsol Multiphysics TM (a Finite Element Analysis tool), and a field solver Atlas/Blaze from Silvaco, are compared qualitatively to study the effect of the deflector position, its size and electric field on the charge transport and its distribution along the channel, resulting in current outputs and leakages in ballistic deflection transistors (BDT). Silvaco simulations and experimental results were then used to study the lateral charge transport as a result of variation in electric field distribution, which controls the charge current along the channel in BDT. The electric field dependence of gain is also studied with experimental and theoretical results.

  18. EFFECTS OF PORE STRUCTURE CHANGE AND MULTI-SCALE HETEROGENEITY ON CONTAMINANT TRANSPORT AND REACTION RATE UPSCALING

    Energy Technology Data Exchange (ETDEWEB)

    Lindquist, W. Brent; Jones, Keith W.; Um, Wooyong; Rockhold, mark; Peters, Catherine A.; Celia, Michael A.

    2013-02-15

    This project addressed the scaling of geochemical reactions to core and field scales, and the interrelationship between reaction rates and flow in porous media. We targeted reactive transport problems relevant to the Hanford site - specifically the reaction of highly caustic, radioactive waste solutions with subsurface sediments, and the immobilization of 90Sr and 129I through mineral incorporation and passive flow blockage, respectively. We addressed the correlation of results for pore-scale fluid-soil interaction with field-scale fluid flow, with the specific goals of (i) predicting attenuation of radionuclide concentration; (ii) estimating changes in flow rates through changes of soil permeabilities; and (iii) estimating effective reaction rates. In supplemental work, we also simulated reactive transport systems relevant to geologic carbon sequestration. As a whole, this research generated a better understanding of reactive transport in porous media, and resulted in more accurate methods for reaction rate upscaling and improved prediction of permeability evolution. These scientific advancements will ultimately lead to better tools for management and remediation of DOE’s legacy waste problems. We established three key issues of reactive flow upscaling, and organized this project in three corresponding thrust areas. 1) Reactive flow experiments. The combination of mineral dissolution and precipitation alters pore network structure and the subsequent flow velocities, thereby creating a complex interaction between reaction and transport. To examine this phenomenon, we conducted controlled laboratory experimentation using reactive flow-through columns. Results and Key Findings: Four reactive column experiments (S1, S3, S4, S5) have been completed in which simulated tank waste leachage (STWL) was reacted with pure quartz sand, with and without Aluminum. The STWL is a caustic solution that dissolves quartz. Because Al is a necessary element in the formation of

  19. Numerical and Experimental Investigation of Turbulent Transport Control via Shaping of Radial Plasma Flow Profiles

    International Nuclear Information System (INIS)

    Gilmore, Mark Allen

    2017-01-01

    Turbulence, and turbulence-driven transport are ubiquitous in magnetically confined plasmas, where there is an intimate relationship between turbulence, transport, instability driving mechanisms (such as gradients), plasma flows, and flow shear. Though many of the detailed physics of the interrelationship between turbulence, transport, drive mechanisms, and flow remain unclear, there have been many demonstrations that transport and/or turbulence can be suppressed or reduced via manipulations of plasma flow profiles. This is well known in magnetic fusion plasmas [e.g., high confinement mode (H-mode) and internal transport barriers (ITB's)], and has also been demonstrated in laboratory plasmas. However, it may be that the levels of particle transport obtained in such cases [e.g. H-mode, ITB's] are actually lower than is desirable for a practical fusion device. Ideally, one would be able to actively feedback control the turbulent transport, via manipulation of the flow profiles. The purpose of this research was to investigate the feasibility of using both advanced model-based control algorithms, as well as non-model-based algorithms, to control cross-field turbulence-driven particle transport through appropriate manipulation of radial plasma flow profiles. The University of New Mexico was responsible for the experimental portion of the project, while our collaborators at the University of Montana provided plasma transport modeling, and collaborators at Lehigh University developed and explored control methods.

  20. Numerical and Experimental Investigation of Turbulent Transport Control via Shaping of Radial Plasma Flow Profiles

    Energy Technology Data Exchange (ETDEWEB)

    Gilmore, Mark Allen [Univ. of New Mexico, Albuquerque, NM (United States)

    2017-02-05

    Turbulence, and turbulence-driven transport are ubiquitous in magnetically confined plasmas, where there is an intimate relationship between turbulence, transport, instability driving mechanisms (such as gradients), plasma flows, and flow shear. Though many of the detailed physics of the interrelationship between turbulence, transport, drive mechanisms, and flow remain unclear, there have been many demonstrations that transport and/or turbulence can be suppressed or reduced via manipulations of plasma flow profiles. This is well known in magnetic fusion plasmas [e.g., high confinement mode (H-mode) and internal transport barriers (ITB’s)], and has also been demonstrated in laboratory plasmas. However, it may be that the levels of particle transport obtained in such cases [e.g. H-mode, ITB’s] are actually lower than is desirable for a practical fusion device. Ideally, one would be able to actively feedback control the turbulent transport, via manipulation of the flow profiles. The purpose of this research was to investigate the feasibility of using both advanced model-based control algorithms, as well as non-model-based algorithms, to control cross-field turbulence-driven particle transport through appropriate manipulation of radial plasma flow profiles. The University of New Mexico was responsible for the experimental portion of the project, while our collaborators at the University of Montana provided plasma transport modeling, and collaborators at Lehigh University developed and explored control methods.

  1. Experimental investigations of the neutron contamination in high-energy photon fields at medical linear accelerators

    International Nuclear Information System (INIS)

    Brunckhorst, Elin

    2009-01-01

    The scope of this thesis was to develop a device for the detection of the photoneutron dose inside the high-energy photon field. The photoneutron contamination of a Siemens PRIMUS linear accelerator was investigated in detail in its 15 MV photon mode. The experimental examinations were performed with three ionisation chambers (a tissue equivalent chamber, a magnesium chamber and a 10 B-coated magnesium chamber) and two types of thermoluminescence detectors (enriched with 6 Li and 7 Li, respectively). The detectors have different sensitivities to photons and neutrons and their combination allows the dose separation in a mixed neutron/photon field. The application of the ionisation chamber system, as well as the present TLD system for photoneutron detection in high-energy photon beams is a new approach. The TLD neutron sensitivity was found to be too low for a measurement inside the open photon field and the further investigation focused on the ionisation chambers. The three ionisation chambers were calibrated at different photon and neutron sources and a the borated magnesium chamber showed a very high response to thermal neutrons. For a cross check of the calibration, the three chambers were also used for dose separation of a boron neutron capture therapy beam where the exact determination of the thermal neutron dose is essential. Very accurate results were achieved for the thermal neutron dose component. At the linear accelerator the chamber system was reduced to a paired chamber system utilising the two magnesium chambers, since the fast neutron component was to small to be separated. The neutron calibration of the three chambers could not be applied, instead a conversion of measured thermal neutron signal by the borated chamber to Monte Carlo simulated total neutron dose was performed. Measurements for open fields in solid water and liquid water were performed with the paired chamber system. In larger depths the neutron dose could be determined with an

  2. Experimental investigations of the neutron contamination in high-energy photon fields at medical linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Brunckhorst, Elin

    2009-02-26

    The scope of this thesis was to develop a device for the detection of the photoneutron dose inside the high-energy photon field. The photoneutron contamination of a Siemens PRIMUS linear accelerator was investigated in detail in its 15 MV photon mode. The experimental examinations were performed with three ionisation chambers (a tissue equivalent chamber, a magnesium chamber and a {sup 10}B-coated magnesium chamber) and two types of thermoluminescence detectors (enriched with {sup 6}Li and {sup 7}Li, respectively). The detectors have different sensitivities to photons and neutrons and their combination allows the dose separation in a mixed neutron/photon field. The application of the ionisation chamber system, as well as the present TLD system for photoneutron detection in high-energy photon beams is a new approach. The TLD neutron sensitivity was found to be too low for a measurement inside the open photon field and the further investigation focused on the ionisation chambers. The three ionisation chambers were calibrated at different photon and neutron sources and a the borated magnesium chamber showed a very high response to thermal neutrons. For a cross check of the calibration, the three chambers were also used for dose separation of a boron neutron capture therapy beam where the exact determination of the thermal neutron dose is essential. Very accurate results were achieved for the thermal neutron dose component. At the linear accelerator the chamber system was reduced to a paired chamber system utilising the two magnesium chambers, since the fast neutron component was to small to be separated. The neutron calibration of the three chambers could not be applied, instead a conversion of measured thermal neutron signal by the borated chamber to Monte Carlo simulated total neutron dose was performed. Measurements for open fields in solid water and liquid water were performed with the paired chamber system. In larger depths the neutron dose could be determined

  3. A 3D FINITE ELEMENT ANALYSIS OF INCOMPRESSIBLE FLUID FLOW AND CONTAMINANT TRANSPORT THROUGH A POROUS LANDFILL

    Directory of Open Access Journals (Sweden)

    ADEGUN, I. K.

    2014-08-01

    Full Text Available The paper investigated the flow of incompressible fluid and contaminant transport through a Porous Landfill using a numerical technique. A threedimensional finite element analysis technique was adopted for the solution. The problem was based on the Darcy’s Law and the Advection-Dispersion equation. The solutions of the Darcy’s and Advection-Dispersion equations were generated using Finite Element Analysis Software known as COMSOL Multiphysics. This simulation tool tracked the contaminant transport in the Landfill for 360 days at 10 days interval. It first modeled steady-state fluid flow by employing the Darcy’s Law Application Mode and then followed up with a transient solute-transport simulation by employing the Solute-Transport Application Mode from the Earth Science Module of COMSOL. The solution results obtained from this model were found to be in close agreement with reallife data obtained at the 130- million ton Bukit Tagar Mega Sanitary Landfill site, Selangor near Kuala Lumpur, Malaysia. This showed that the model can effectively predict the trends in the distributions of pollutants from a Municipal Solid Waste Landfill into nearby land and water sources. The model is thus applicable to the issues of environmental protection and safety of groundwater.

  4. Biogeochemical Attributes That Affect the Fate and Transport of Military Relevant Contaminants Under Freeze-thaw Conditions

    Science.gov (United States)

    LeMonte, J.; Price, C. L.; Seiter, J.; Crocker, F. H.; Douglas, T.; Chappell, M. A.

    2017-12-01

    The roles and missions that the U.S. Department of Defense (DoD) undertakes in the Arctic are being reshaped by significant changes in the operational environment as a result of rising global temperatures and increased development of the vast training ranges available in Alaska. The Arctic is warming faster than any other region on Earth resulting in changing seasonality and precipitation patterns that, in turn, are leading to alterations in above ground vegetation, permafrost stability and summer sea ice extent. Collectively, these poorly defined ecosystem changes play critical roles in affecting the transport and eventual fate of persistent military relevant contaminants through unique Arctic and Subarctic terrestrial environments. As a result, management of military contaminants in a changing Arctic represents a unique and potentially significant liability to the Army and the DoD. The United States footprint in the Arctic region falls within the state of Alaska and U.S. Army Alaska manages 10% of all active Army training lands worldwide, which cover nearly 2,500 square miles in total land area. Primary recalcitrant contaminants of concern at active training ranges and at legacy sites include energetics (i.e. RDX and 2,4-dinitrotoluene) and heavy metals (i.e. antimony and lead). Through a series of field sampling and laboratory experiments, the objectives of this work are to: 1) quantify soil biogeochemical attributes that effect the physical fate and transport of military relevant contaminants in Arctic and subarctic soils under freeze-thaw conditions with a focus on near surface processes, and 2) quantify microbial diversity in Arctic and subarctic soils and the environmental constraints on community activity while exploring the effects of amendments on community function as they relate to contaminant transformation.

  5. Long-term environmental and health implications of morphological change and sediment transport with respect to contaminants

    Science.gov (United States)

    Sneddon, Christopher; Copplestone, David; Tyler, Andrew; Hunter, Peter; Smith, Nick

    2014-05-01

    The EPSRC-funded Adaptation and Resilience of Coastal Energy Supply (ARCoES) project encompasses four research strands, involving 14 institutions and six PhD studentships. ARCoES aims to determine the threats posed to future energy generation and the distribution network by flooding and erosion, changing patterns of coastal sedimentation, water temperature and the distribution of plants and animals in the coastal zone. Whilst this research has direct benefits for the operation of coastal power stations, ARCoES aims to have a wider stakeholder engagement through assessing how the resilience of coastal communities may be altered by five hundred years of coastal evolution. Coastal evolution will have substantial implications for the energy sector of the North West of England as former waste storage sites are eroded and remobilised within the intertidal environment. The current intertidal environmental stores of radioactivity will also experience reworking as ocean chemistry changes and saltmarsh chronologies are reworked in response to rising sea levels. There is a duel requirement to understand mass sediment movement along the North West coast of England as understanding the sediment transport dynamics is key to modelling long term coastal change and understanding how the environmental store of radioactivity will be reworked. The University of Stirling is researching the long-term environmental and health implications of remobilisation and transport of contaminated sediments around the UK coastline. Using a synergy of hyperspectral and topographic information the mobilisation of sediment bound contaminants within the coastal environment will be investigated. Potential hazards posed by contaminants are determined by a set of environmental impact test criteria which evaluate the bio-accessibility and ionising dose of contaminants. These test criteria will be used to comment on the likely environmental impact of modelled sediment transport and anticipated changes in

  6. Contaminant geochemistry. Interactions and transport in the subsurface environment. 2. ed.

    Energy Technology Data Exchange (ETDEWEB)

    Berkowitz, Brian; Dror, Ishai; Yaron, Bruno [Weizmann Institute of Science, Rehovot (Israel). Dept. of Earth and Planetary Sciences

    2014-07-01

    In this updated and expanded second edition, new literature has been added on contaminant fate in the soil-subsurface environment. In particular, more data on the behavior of inorganic contaminants and on engineered nanomaterials were included, the latter comprising a group of ''emerging contaminants'' that may reach the soil and subsurface zones. New chapters are devoted to a new perspective of contaminant geochemistry, namely irreversible changes in pristine land and subsurface systems following chemical contamination. Two chapters were added on this topic, focusing attention on the impact of chemical contaminants on the matrix and properties of both liquid and solid phases of soil and subsurface domains. Contaminant impacts on irreversible changes occurring in groundwater are discussed and their irreversible changes on the porous medium solid phase are surveyed. In contrast to the geological time scale controlling natural changes of porous media liquid and solid phases, the time scale associated with chemical pollutant induced changes is far shorter and extends over a ''human lifetime scale''.

  7. Transport and transformation of pharmaceuticals and other contaminants of emerging concern from wastewater discharge through surface water to drinking water intake and treatment

    Science.gov (United States)

    The ubiquitous presence of pharmaceuticals, hormones, and other contaminants of emerging concern (CECs) in surface-water resources have necessitated research that better elucidates pathways of transport and transformation for these compounds from their discharged wastewater, thro...

  8. Isolation of HIV-1 from experimentally contaminated multidose local anaesthetic vials.

    Science.gov (United States)

    Druce, J D; Locarnini, S A; Birch, C J

    1995-05-15

    To investigate the hypothesis that HIV can be transmitted via contamination of multidose vials of local anaesthetic solution through reuse of needles and syringes. Laboratory study. (1) By experiments with multidose vials and disposable needles and syringes, we identified a sequence of events in which HIV could contaminate the anaesthetic solution. (2) Three anaesthetic solutions were contaminated with a laboratory strain of HIV and tested by viral culture and p24 enzyme immunoassay one, two and four hours later to see how long the virus remained active. (1) Needles and syringes retained small volumes of fluid after use (mean, 25 microL; in syringe alone, mean 16 microL) which could be transferred to multidose vials of local anaesthetic. (2) 10 mL of anaesthetic solution contaminated with 8 microL of HIV-infected solution (equivalent to 1% infected lymphocytes in vivo) contained active virus one hour later. In some settings, HIV could be isolated four hours after exposure. When inadvertently contaminated with HIV, multidose solutions represent a potential source of transmissible virus.

  9. Experimental study of the complex resistivity and dielectric constant of chrome-contaminated soil

    Science.gov (United States)

    Liu, Haorui; Yang, Heli; Yi, Fengyan

    2016-08-01

    Heavy metals such as arsenic and chromium often contaminate soils near industrialized areas. Soil samples, made with different water content and chromate pollutant concentrations, are often needed to test soil quality. Because complex resistivity and complex dielectric characteristics of these samples need to be measured, the relationship between these measurement results and chromium concentration as well as water content was studied. Based on soil sample observations, the amplitude of the sample complex resistivity decreased with an increase of contamination concentration and water content. The phase of complex resistivity takes on a tendency of initially decrease, and then increase with the increasing of contamination concentration and water content. For a soil sample with the same resistivity, the higher the amplitude of complex resistivity, the lower the water content and the higher the contamination concentration. The real and imaginary parts of the complex dielectric constant increase with an increase in contamination concentration and water content. Note that resistivity and complex resistivity methods are necessary to adequately evaluate pollution at various sites.

  10. Interaction of environmental contaminants with zebrafish organic anion transporting polypeptide, Oatp1d1 (Slco1d1)

    Energy Technology Data Exchange (ETDEWEB)

    Popovic, Marta; Zaja, Roko [Laboratory for Molecular Ecotoxicology, Division for Marine and Environmental Research, Rudjer Boskovic Institute, Bijenicka 54, 10 000 Zagreb (Croatia); Fent, Karl [University of Applied Sciences Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz (Switzerland); Swiss Federal Institute of Technology (ETH Zürich), Department of Environmental System Sciences, Institute of Biogeochemistry and Pollution Dynamics, CH-8092 Zürich (Switzerland); Smital, Tvrtko, E-mail: smital@irb.hr [Laboratory for Molecular Ecotoxicology, Division for Marine and Environmental Research, Rudjer Boskovic Institute, Bijenicka 54, 10 000 Zagreb (Croatia)

    2014-10-01

    Polyspecific transporters from the organic anion transporting polypeptide (OATP/Oatp) superfamily mediate the uptake of a wide range of compounds. In zebrafish, Oatp1d1 transports conjugated steroid hormones and cortisol. It is predominantly expressed in the liver, brain and testes. In this study we have characterized the transport of xenobiotics by the zebrafish Oatp1d1 transporter. We developed a novel assay for assessing Oatp1d1 interactors using the fluorescent probe Lucifer yellow and transient transfection in HEK293 cells. Our data showed that numerous environmental contaminants interact with zebrafish Oatp1d1. Oatp1d1 mediated the transport of diclofenac with very high affinity, followed by high affinity towards perfluorooctanesulfonic acid (PFOS), nonylphenol, gemfibrozil and 17α-ethinylestradiol; moderate affinity towards carbaryl, diazinon and caffeine; and low affinity towards metolachlor. Importantly, many environmental chemicals acted as strong inhibitors of Oatp1d1. A strong inhibition of Oatp1d1 transport activity was found by perfluorooctanoic acid (PFOA), chlorpyrifos-methyl, estrone (E1) and 17β-estradiol (E2), followed by moderate to low inhibition by diethyl phthalate, bisphenol A, 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4 tetrahydronapthalene and clofibrate. In this study we identified Oatp1d1 as a first Solute Carrier (SLC) transporter involved in the transport of a wide range of xenobiotics in fish. Considering that Oatps in zebrafish have not been characterized before, our work on zebrafish Oatp1d1 offers important new insights on the understanding of uptake processes of environmental contaminants, and contributes to the better characterization of zebrafish as a model species. - Highlights: • We optimized a novel assay for determination of Oatp1d1 interactors • Oatp1d1 is the first SLC characterized fish xenobiotic transporter • PFOS, nonylphenol, diclofenac, EE2, caffeine are high affinity Oatp1d1substrates • PFOA, chlorpyrifos

  11. Interaction of environmental contaminants with zebrafish organic anion transporting polypeptide, Oatp1d1 (Slco1d1)

    International Nuclear Information System (INIS)

    Popovic, Marta; Zaja, Roko; Fent, Karl; Smital, Tvrtko

    2014-01-01

    Polyspecific transporters from the organic anion transporting polypeptide (OATP/Oatp) superfamily mediate the uptake of a wide range of compounds. In zebrafish, Oatp1d1 transports conjugated steroid hormones and cortisol. It is predominantly expressed in the liver, brain and testes. In this study we have characterized the transport of xenobiotics by the zebrafish Oatp1d1 transporter. We developed a novel assay for assessing Oatp1d1 interactors using the fluorescent probe Lucifer yellow and transient transfection in HEK293 cells. Our data showed that numerous environmental contaminants interact with zebrafish Oatp1d1. Oatp1d1 mediated the transport of diclofenac with very high affinity, followed by high affinity towards perfluorooctanesulfonic acid (PFOS), nonylphenol, gemfibrozil and 17α-ethinylestradiol; moderate affinity towards carbaryl, diazinon and caffeine; and low affinity towards metolachlor. Importantly, many environmental chemicals acted as strong inhibitors of Oatp1d1. A strong inhibition of Oatp1d1 transport activity was found by perfluorooctanoic acid (PFOA), chlorpyrifos-methyl, estrone (E1) and 17β-estradiol (E2), followed by moderate to low inhibition by diethyl phthalate, bisphenol A, 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4 tetrahydronapthalene and clofibrate. In this study we identified Oatp1d1 as a first Solute Carrier (SLC) transporter involved in the transport of a wide range of xenobiotics in fish. Considering that Oatps in zebrafish have not been characterized before, our work on zebrafish Oatp1d1 offers important new insights on the understanding of uptake processes of environmental contaminants, and contributes to the better characterization of zebrafish as a model species. - Highlights: • We optimized a novel assay for determination of Oatp1d1 interactors • Oatp1d1 is the first SLC characterized fish xenobiotic transporter • PFOS, nonylphenol, diclofenac, EE2, caffeine are high affinity Oatp1d1substrates • PFOA, chlorpyrifos

  12. Experimental Research Regarding the Application of Electro-Flushing Method on Diesel Contaminated Soils

    Directory of Open Access Journals (Sweden)

    Streche Constantin

    2014-05-01

    Full Text Available In 2011, as a result of the inventory conducted at the national level, The Ministry Of Environment concluded that the largest number of contaminated sites with hydrocarbons are due to the petroleum products distribution (nearly 400 sites, followed by the hydrocarbons extraction (about 310 sites. So, soil contamination with liquid petroleum products resulting from many industrial activities became an important issue of environment protection. Unfortunately not all local governments have provided a list of contaminated sites, which means that there is a possibility to have a bigger problem at the national level. All these surfaces are in a continuous growth due to industrial and social development and that is why it is necessary to study and improve decontamination methods of contaminated sites in order to regain one of our most important resources - the soil. In this paper, the main results obtained during a research that aimed to study two different treatment methods of contaminated soil in a combined solution, are presented. The newly developed method is called electro-flushing. Results proved that combining the two nominated methods could be a viable solution for treating diesel polluted soil with better performances comparing with using them separately. Concerning the electrochemical treatment of diesel contaminated soils an efficiency of 35-40 % could be obtained after 28 days; while using the flushing method up to 15-20% efficiency could be reached. On the other hand, if we combine these two methods, we can reach remediation efficiency up to 50%. So, the main interesting results of the present research is given by the fact that combining two known remediation methods, better performances could be achieved.

  13. Sediment Capping and Natural Recovery, Contaminant Transport Fundamentals With Applications to Sediment Caps

    National Research Council Canada - National Science Library

    Petrovski, David M; Corcoran, Maureen K; May, James H; Patrick, David M

    2005-01-01

    Engineered sediment caps and natural recovery are in situ remedial alternatives for contaminated sediments, which consist of the artificial or natural placement of a layer of material over a sediment...

  14. Experimental evaluation of washing for treatment of combustible plutonium-contaminated materials

    International Nuclear Information System (INIS)

    Wilkins, J.D.; Wisbey, S.J.

    1983-03-01

    Laboratory scale experiments have been carried out in order to assess the potential of washing as a method for removing plutonium from contaminated combustible wastes. A wide range of aqueous (eg 1 M HNO 3 , 1 M NaOH) and organic (1,1,2-trichlorotrifluoroethane) reagents have been investigated. Both synthetically contaminated and real wastes have been investigated. The preferred wash reagent has been identified as 1 M sodium hydroxide solution; plutonium recoveries of ca.80 to 90% can be achieved. (author)

  15. Deterministic sensitivity analysis for the numerical simulation of contaminants transport; Analyse de sensibilite deterministe pour la simulation numerique du transfert de contaminants

    Energy Technology Data Exchange (ETDEWEB)

    Marchand, E

    2007-12-15

    The questions of safety and uncertainty are central to feasibility studies for an underground nuclear waste storage site, in particular the evaluation of uncertainties about safety indicators which are due to uncertainties concerning properties of the subsoil or of the contaminants. The global approach through probabilistic Monte Carlo methods gives good results, but it requires a large number of simulations. The deterministic method investigated here is complementary. Based on the Singular Value Decomposition of the derivative of the model, it gives only local information, but it is much less demanding in computing time. The flow model follows Darcy's law and the transport of radionuclides around the storage site follows a linear convection-diffusion equation. Manual and automatic differentiation are compared for these models using direct and adjoint modes. A comparative study of both probabilistic and deterministic approaches for the sensitivity analysis of fluxes of contaminants through outlet channels with respect to variations of input parameters is carried out with realistic data provided by ANDRA. Generic tools for sensitivity analysis and code coupling are developed in the Caml language. The user of these generic platforms has only to provide the specific part of the application in any language of his choice. We also present a study about two-phase air/water partially saturated flows in hydrogeology concerning the limitations of the Richards approximation and of the global pressure formulation used in petroleum engineering. (author)

  16. On the Dielectric Constant for Acetanilide: Experimental Measurements and Effect on Energy Transport

    Science.gov (United States)

    Careri, G.; Compatangelo, E.; Christiansen, P. L.; Halding, J.; Skovgaard, O.

    1987-01-01

    Experimental measurements of the dielectric constant for crystalline acetanilide powder for temperatures ranging from - 140°C to 20°C and for different hydration levels are presented. A Davydov-soliton computer model predicts dramatic changes in the energy transport and storage for typically increased values of the dielectric constant.

  17. Bacterial contamination on touch surfaces in the public transport system and in public areas of a hospital in London.

    Science.gov (United States)

    Otter, J A; French, G L

    2009-12-01

    To investigate bacterial contamination on hand-touch surfaces in the public transport system and in public areas of a hospital in central London. Dipslides were used to sample 118 hand-touch surfaces in buses, trains, stations, hotels and public areas of a hospital in central London. Total aerobic counts were determined, and Staphylococcus aureus isolates were identified and characterized. Bacteria were cultured from 112 (95%) of sites at a median concentration of 12 CFU cm(-2). Methicillin-susceptible Staph. aureus (MSSA) was cultured from nine (8%) of sites; no sites grew methicillin-resistant Staph. aureus (MRSA). Hand-touch sites in London are frequently contaminated with bacteria and can harbour MSSA, but none of the sites tested were contaminated with MRSA. Hand-touch sites can become contaminated with staphylococci and may be fomites for the transmission of bacteria between humans. Such sites could provide a reservoir for community-associated MRSA (CA-MRSA) in high prevalence areas but were not present in London, a geographical area with a low incidence of CA-MRSA.

  18. Predicting soil, water and air concentrations of environmental contaminants locally and regionally; multimedia transport and transformation models

    International Nuclear Information System (INIS)

    McKone, T.E.; Daniels, J.I.

    1991-01-01

    Environmental scientists recognize that the environment functions as a complex, interconnected system. A realistic risk-management strategy for many contaminants requires a comprehensive and integrated assessment of local and regional transport and transformation processes. In response to this need, we have developed multimedia models that simulate the movement and transformation of chemicals as they spread through air, water, biota, soils, sediments, surface water and ground water. Each component of the environment is treated as a homogeneous subsystem that can exchange water, nutrients, and chemical contaminants with other adjacent compartments. In this paper, we illustrate the use of multimedia models and measurements as tools for screening the potential risks of contaminants released to air and deposited onto soil and plants. The contaminant list includes the volatile organic compounds (VOCs) tetrachloroethylene (PCE) and trichloroethylene (TCE), the semi-volatile organic compound benzo(a)pyrene, and the radionuclides tritium and uranium-238. We examine how chemical properties effect both the ultimate route and quantity of human and ecosystem contact and identify sensitivities and uncertainties in the model results. We consider the advantages of multimedia models relative to environmental monitoring data. (au)

  19. Predicting soil, water, and air concentrations of environmental contaminants locally and regionally: Multimedia transport and transformation models

    International Nuclear Information System (INIS)

    McKone, T.E.; Daniels, J.I.

    1991-10-01

    Environmental scientists recognize that the environment functions as a complex, interconnected system. A realistic risk-management strategy for many contaminants requires a comprehensive and integrated assessment of local and regional transport and transformation processes. In response to this need, we have developed multimedia models that simulate the movement and transformation of chemicals as they spread through air, water, biota, soils, sediments, surface water, and ground water. Each component of the environment is treated as a homogeneous subsystem that can exchange water, nutrients, and chemical contaminants with other adjacent compartments. In this paper, we illustrate the use of multimedia models and measurements as tools for screening the potential risks of contaminants released to air and deposited onto soil and plants. The contaminant list includes the volatile organic compounds (VOCs) tetrachloroethylene (PCE) and trichloroethylene (TCE), the semi-volatile organic compound benzo(a)pyrene, and the radionuclides tritium and uranium-238. We examine how chemical properties effect both the ultimate route and quantity of human and ecosystem contact and identify sensitivities and uncertainties in the model results

  20. Interfacial Reduction-Oxidation Mechanisms Governing Fate and Transport of Contaminants in the Vadose Zone

    Energy Technology Data Exchange (ETDEWEB)

    Principal Investigator: Baolin Deng, University of Missouri, Columbia, MO; Co-Principal Investigator: Silvia Sabine Jurisson, University of Missouri, Columbia, MO; Co-Principal Investigator: Edward C. Thornton, Pacific Northwest National Laboratory Richland, WA; Co-Principal Investigator: Jeff Terry, Illinois Institute of Technology, Chicago, IL

    2008-05-12

    There are many soil contamination sites at the Department of Energy (DOE) installations that contain radionuclides and toxic metals such as uranium (U), technetium (Tc), and chromium (Cr). Since these contaminants are the main 'risk drivers' at the Hanford site (WA) and some of them also pose significant risk at other DOE facilities (e.g., Oak Ridge Reservation - TN; Rocky Flats - CO), development of technologies for cost effective site remediation is needed. Current assessment indicates that complete removal of these contaminants for ex-situ disposal is infeasible, thus in-situ stabilization through reduction to insoluble species is considered one of the most important approaches for site remediation. In Situ Gaseous Reduction (ISGR) is a technology developed by Pacific Northwest National Laboratory (PNNL) for vadose zone soil remediation. The ISGR approach uses hydrogen sulfide (H{sub 2}S) for reductive immobilization of contaminants that show substantially lower mobility in their reduced forms (e.g., Tc, U, and Cr). The technology can be applied in two ways: (i) to immobilize or stabilize pre-existing contaminants in the vadose zone soils by direct H{sub 2}S treatment, or (ii) to create a permeable reactive barrier (PRB) that prevents the migration of contaminants. Direct treatment involves reduction of the contaminants by H{sub 2}S to less mobile species. Formation of a PRB is accomplished through reduction of ferric iron species in the vadose zone soils by H{sub 2}S to iron sulfides (e.g., FeS), which provides a means for capturing the contaminants entering the treated zone. Potential future releases may occur during tank closure activities. Thus, the placement of a permeable reactive barrier by ISGR treatment can be part of the leak mitigation program. Deployment of these ISGR approaches, however, requires a better understanding of the immobilization kinetics and mechanisms, and a better assessment of the long-term effectiveness of treatment. The

  1. Experimental Investigation of Phenanthrene Pollutant Removal Efficiency for Contaminated Sandy Soil by Enhanced Soil Washing

    Directory of Open Access Journals (Sweden)

    Saif salah Alquzweeni

    2016-12-01

    Full Text Available Polycyclic aromatic hydrocarbons (PAHs are environmental concerns that must be removed to acceptable level. This research assesses two agents (Na2EDTA and SDS to remediate contaminated sandy soil, spiked with 500mg/kg phenanthrene. Five sets of experiments (batch are applied to investigate the optimal of five influencing factors on soil remediation: Na2EDTA-SDS concentration, liquid/Solid ratio, stirring speed, pH value of flushing solution and mixing time. The results of batch experiments showed that SDS has high phenanthrene removal efficiency (90%, while Na2EDTA shows no phenanthrene removal. pH has no effect on phenanthrene removal. To study the influence of flow rates on the removal efficiency of contaminants, two column tests with hydraulic gradient of 0.2 and 1.2 conducted by SDS solution. The results illustrate that high phenanthrene removal from soil obtained by 1.2 hydraulic gradient condition. The SDS flushing solution removed approximately 69% and 81% of phenanthrene from soil under low and high hydraulic gradients, respectively. It was concluded that phenanthrene removal depend on surfactant micelles formation. Overall, the study showed that soil flushing removal efficiency for contaminants depends on the flushing agents selectivity and affinity to the contaminants and the condition of hydraulic gradient.

  2. Leaching of heavy metals from contaminated soils: An experimental and modeling study

    NARCIS (Netherlands)

    Dijkstra, J.J.; Meeussen, J.C.L.; Comans, R.N.J.

    2004-01-01

    In this paper, we characterize the leaching of heavy metals (Ni, Cu, Zn, Cd, and Pb) from eight contaminated soils over a wide range of pH (pH 0.4-12) using an original approach based on batch pH-static leaching experiments in combination with selective chemical extractions and geochemical modeling.

  3. Experimental validation of GADRAS's coupled neutron-photon inverse radiation transport solver

    International Nuclear Information System (INIS)

    Mattingly, John K.; Mitchell, Dean James; Harding, Lee T.

    2010-01-01

    Sandia National Laboratories has developed an inverse radiation transport solver that applies nonlinear regression to coupled neutron-photon deterministic transport models. The inverse solver uses nonlinear regression to fit a radiation transport model to gamma spectrometry and neutron multiplicity counting measurements. The subject of this paper is the experimental validation of that solver. This paper describes a series of experiments conducted with a 4.5 kg sphere of α-phase, weapons-grade plutonium. The source was measured bare and reflected by high-density polyethylene (HDPE) spherical shells with total thicknesses between 1.27 and 15.24 cm. Neutron and photon emissions from the source were measured using three instruments: a gross neutron counter, a portable neutron multiplicity counter, and a high-resolution gamma spectrometer. These measurements were used as input to the inverse radiation transport solver to evaluate the solver's ability to correctly infer the configuration of the source from its measured radiation signatures.

  4. Experimental and analytical study of interfacial area transport phenomena in a vertical two-phase flow

    International Nuclear Information System (INIS)

    Huh, Byung-Gil; Euh, Dong-Jin; Yun, Byong-Jo; Youn, Young-Jung; Yoon, Han-Yeong; Song, Chul-Hwa

    2005-03-01

    The number density transport equations for various bubble groups are used to predict the void fraction and the interfacial area concentration. As the closure relations for number density transport equation, the coalescence due to random collisions and the breakup due to the impact of turbulent eddies is modified based on the previous studies and the bubble expansion term due to the pressure reduction is considered. Also, the coalescence due to a wake entrainment is modeled newly to apply to the number density transport equation. In order to predict the local experimental data, the code is developed that the two-fluid model is coupled systematically with the number density transport equation for each bubble group. As for the results of the numerical analysis, the void fraction and interfacial area concentration are predicted well by the developed code and models although some deviations exist in the values between the prediction and experiment, especially, for the high void fraction conditions

  5. Experimental and analytical study of interfacial area transport phenomena in a vertical two-phase flow

    Energy Technology Data Exchange (ETDEWEB)

    Huh, Byung-Gil; Euh, Dong-Jin; Yun, Byong-Jo; Youn, Young-Jung; Yoon, Han-Yeong; Song, Chul-Hwa

    2005-03-01

    The number density transport equations for various bubble groups are used to predict the void fraction and the interfacial area concentration. As the closure relations for number density transport equation, the coalescence due to random collisions and the breakup due to the impact of turbulent eddies is modified based on the previous studies and the bubble expansion term due to the pressure reduction is considered. Also, the coalescence due to a wake entrainment is modeled newly to apply to the number density transport equation. In order to predict the local experimental data, the code is developed that the two-fluid model is coupled systematically with the number density transport equation for each bubble group. As for the results of the numerical analysis, the void fraction and interfacial area concentration are predicted well by the developed code and models although some deviations exist in the values between the prediction and experiment, especially, for the high void fraction conditions.

  6. An Iterative Ensemble Kalman Filter with One-Step-Ahead Smoothing for State-Parameters Estimation of Contaminant Transport Models

    KAUST Repository

    Gharamti, M. E.

    2015-05-11

    The ensemble Kalman filter (EnKF) is a popular method for state-parameters estimation of subsurface flow and transport models based on field measurements. The common filtering procedure is to directly update the state and parameters as one single vector, which is known as the Joint-EnKF. In this study, we follow the one-step-ahead smoothing formulation of the filtering problem, to derive a new joint-based EnKF which involves a smoothing step of the state between two successive analysis steps. The new state-parameters estimation scheme is derived in a consistent Bayesian filtering framework and results in separate update steps for the state and the parameters. This new algorithm bears strong resemblance with the Dual-EnKF, but unlike the latter which first propagates the state with the model then updates it with the new observation, the proposed scheme starts by an update step, followed by a model integration step. We exploit this new formulation of the joint filtering problem and propose an efficient model-integration-free iterative procedure on the update step of the parameters only for further improved performances. Numerical experiments are conducted with a two-dimensional synthetic subsurface transport model simulating the migration of a contaminant plume in a heterogenous aquifer domain. Contaminant concentration data are assimilated to estimate both the contaminant state and the hydraulic conductivity field. Assimilation runs are performed under imperfect modeling conditions and various observational scenarios. Simulation results suggest that the proposed scheme efficiently recovers both the contaminant state and the aquifer conductivity, providing more accurate estimates than the standard Joint and Dual EnKFs in all tested scenarios. Iterating on the update step of the new scheme further enhances the proposed filter’s behavior. In term of computational cost, the new Joint-EnKF is almost equivalent to that of the Dual-EnKF, but requires twice more model

  7. Experimental and theoretical study of particle transport in the TCV Tokamak

    International Nuclear Information System (INIS)

    Fable, E.

    2009-06-01

    The main scope of this thesis work is to compare theoretical models with experimental observations on particle transport in particular regimes of plasma operation from the Tokamak à Configuration Variable (TCV) located at CRPP–EPFL in Lausanne. We introduce the main topics in Tokamak fusion research and the challenging problems in the first Chapter. A particular attention is devoted to the modelling of heat and particle transport. In the second Chapter the experimental part is presented, including an overview of TCV capabilities, a brief review of the relevant diagnostic systems, and a discussion of the numerical tools used to analyze the experimental data. In addition, the numerical codes that are used to interpret the experimental data and to compare them with theoretical predictions are introduced. The third Chapter deals with the problem of understanding the mechanisms that regulate the transport of energy in TCV plasmas, in particular in the electron Internal Transport Barrier (eITB) scenario. A radial transport code, integrated with an external module for the calculation of the turbulence-induced transport coefficients, is employed to reproduce the experimental scenario and to understand the physics at play. It is shown how the sustainment of an improved confinement regime is linked to the presence of a reversed safety factor profile. The improvement of confinement in the eITB regime is visible in the energy channel and in the particle channel as well. The density profile shows strong correlation with the temperature profile and has a large local logarithmic gradient. This is an important result obtained from the TCV eITB scenario analysis and is presented in the fourth Chapter. In the same chapter we present the estimate of the particle diffusion and convection coefficients obtained from density transient experiments performed in the eITB scenario. The theoretical understanding of the strong correlation between density and temperature observed in the e

  8. Transport of microbial tracers in clean and organically contaminated silica sand in laboratory columns compared with their transport in the field

    International Nuclear Information System (INIS)

    Weaver, Louise; Sinton, Lester W.; Pang, Liping; Dann, Rod; Close, Murray

    2013-01-01

    Waste disposal on land and the consequent transport of bacterial and viral pathogens in soils and aquifers are of major concern worldwide. Pathogen transport can be enhanced in the presence of organic matter due to occupation of attachment sites in the aquifer materials thus preventing pathogen attachment leading to their faster transport for longer distances. Laboratory column studies were carried out to investigate the effect of organic matter, in the form of dissolved organic carbon (DOC), on the transport of Escherichia coli and MS2 phage in saturated clean silica sand. Transport rates of these microbial tracers were also studied in a contaminated field site. Laboratory column studies showed that low concentrations (0.17 mg L −1 ) of DOC had little effect on E. coli J6-2 removal and slightly reduced the attachment of MS2 phage. After progressive conditioning of the column with DOC (1.7 mg L −1 and 17 mg L −1 ), neither E. coli J6-2 nor MS2 phage showed any attachment and recovery rates increased dramatically (up to 100%). The results suggest that DOC can affect the transport rates of microbial contaminants. For E. coli J6-2 the predominant effect appeared to be an increase in the secondary energy minimum leading to an increase in E. coli attachment initially. However, after 17 mg L −1 DOC conditioning of the silica sand no attachment of E. coli was observed as the DOC took up attachment sites in the porous media. MS2 phage appeared to be affected predominantly by out-competition of binding sites in the clean silica sand and a steady reduction in attachment was observed as the DOC conditioning increased. Field study showed a high removal of both E. coli and MS2 phage, although E. coli was removed at a lower rate than MS2 phage. In the field it is likely that a combination of effects are seen as the aquifer material will be heterogeneous in its surface nanoscale properties, demonstrated by the differing removal of E. coli and MS2 phage compared to the

  9. Factors influencing aquatic-to-terrestrial contaminant transport to terrestrial arthropod consumers in a multiuse river system.

    Science.gov (United States)

    Alberts, Jeremy M; Sullivan, S Mažeika P

    2016-06-01

    Emerging aquatic insects are important vectors of contaminant transfer from aquatic to terrestrial food webs. However, the environmental factors that regulate contaminant body burdens in nearshore terrestrial consumers remain largely unexplored. We investigated the relative influences of riparian landscape composition (i.e., land use and nearshore vegetation structure) and contaminant flux via the emergent aquatic insect subsidy on selenium (Se) and mercury (Hg) body burdens of riparian ants (Formica subsericea) and spiders of the family Tetragnathidae along 11 river reaches spanning an urban-rural land-use gradient in Ohio, USA. Model-selection results indicated that fine-scale land cover (e.g., riparian zone width, shrub cover) in the riparian zone was positively associated with reach-wide body burdens of Se and Hg in both riparian F. subsericea and tetragnathid spiders (i.e., total magnitude of Hg and Se concentrations in ant and spider populations, respectively, for each reach). River distance downstream of Columbus, Ohio - where study reaches were impounded and flow through a large urban center - was also implicated as an important factor. Although stable-isotope analysis suggested that emergent aquatic insects were likely vectors of Se and Hg to tetragnathid spiders (but not to F. subsericea), emergent insect contaminant flux did not emerge as a significant predictor for either reach-wide body burdens of spider Hg or Se. Improved understanding of the pathways and influences that control aquatic-to-terrestrial contaminant transport will be critical for effective risk management and remediation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Experimental characterization of solid particle transport by slug flow using Particle Image Velocimetry

    International Nuclear Information System (INIS)

    Goharzadeh, A; Rodgers, P

    2009-01-01

    This paper presents an experimental study of gas-liquid slug flow on solid particle transport inside a horizontal pipe with two types of experiments conducted. The influence of slug length on solid particle transportation is characterized using high speed photography. Using combined Particle Image Velocimetry (PIV) with Refractive Index Matching (RIM) and fluorescent tracers (two-phase oil-air loop) the velocity distribution inside the slug body is measured. Combining these experimental analyses, an insight is provided into the physical mechanism of solid particle transportation due to slug flow. It was observed that the slug body significantly influences solid particle mobility. The physical mechanism of solid particle transportation was found to be discontinuous. The inactive region (in terms of solid particle transport) upstream of the slug nose was quantified as a function of gas-liquid composition and solid particle size. Measured velocity distributions showed a significant drop in velocity magnitude immediately upstream of the slug nose and therefore the critical velocity for solid particle lifting is reached further upstream.

  11. Experimental bifurcation analysis—Continuation for noise-contaminated zero problems

    DEFF Research Database (Denmark)

    Schilder, Frank; Bureau, Emil; Santos, Ilmar Ferreira

    2015-01-01

    Noise contaminated zero problems involve functions that cannot be evaluated directly, but only indirectly via observations. In addition, such observations are affected by a non-deterministic observation error (noise). We investigate the application of numerical bifurcation analysis for studying...... the solution set of such noise contaminated zero problems, which is highly relevant in the context of equation-free analysis (coarse grained analysis) and bifurcation analysis in experiments, and develop specialized algorithms to address challenges that arise due to the presence of noise. As a working example......, we demonstrate and test our algorithms on a mechanical nonlinear oscillator experiment using control based continuation, which we used as a main application and test case for development of the Coco compatible Matlab toolbox Continex that implements our algorithms....

  12. Chemical disinfection of non-porous inanimate surfaces experimentally contaminated with four human pathogenic viruses.

    OpenAIRE

    Sattar, S. A.; Springthorpe, V. S.; Karim, Y.; Loro, P.

    1989-01-01

    The chemical disinfection of virus-contaminated non-porous inanimate surfaces was investigated using coxsackievirus B3, adenovirus type 5, parainfluenza virus type 3 and coronavirus 229E as representatives of important nosocomial viral pathogens. A 10 microliter amount of the test virus, suspended in either faeces or mucin, was placed onto each stainless steel disk (about 1 cm in diameter) and the inoculum allowed to dry for 1 h under ambient conditions. Sixteen disinfectant formulations were...

  13. Designing the ideal model for assessment of wound contamination after gunshot injuries: a comparative experimental study

    Directory of Open Access Journals (Sweden)

    von See Constantin

    2012-04-01

    Full Text Available Abstract Background Modern high-velocity projectiles produce temporary cavities and can thus cause extensive tissue destruction along the bullet path. It is still unclear whether gelatin blocks, which are used as a well-accepted tissue simulant, allow the effects of projectiles to be adequately investigated and how these effects are influenced by caliber size. Method Barium titanate particles were distributed throughout a test chamber for an assessment of wound contamination. We fired .22-caliber Magnum bullets first into gelatin blocks and then into porcine hind limbs placed behind the chamber. Two other types of bullets (.222-caliber bullets and 6.5 × 57 mm cartridges were then shot into porcine hind limbs. Permanent and temporary wound cavities as well as the spatial distribution of barium titanate particles in relation to the bullet path were evaluated radiologically. Results A comparison of the gelatin blocks and hind limbs showed significant differences (p Conclusion Gelatin is only of limited value for evaluating the path of high-velocity projectiles and the contamination of wounds by exogenous particles. There is a direct relationship between the presence of gas cavities in the tissue along the bullet path and caliber size. These cavities, however, are only mildly contaminated by exogenous particles.

  14. Removal of polycyclic aromatic hydrocarbons from aged-contaminated soil using cyclodextrins: Experimental study

    International Nuclear Information System (INIS)

    Viglianti, Christophe; Hanna, Khalil; Brauer, Christine de; Germain, Patrick

    2006-01-01

    The removal of polycyclic aromatic hydrocarbons (PAHs) from soil using water as flushing agent is relatively ineffective due to their low aqueous solubility. However, addition of cyclodextrin (CD) in washing solutions has been shown to increase the removal efficiency several times. Herein are investigated the effectiveness of cyclodextrin to remove PAH occurring in industrially aged-contaminated soil. β-Cyclodextrin (BCD), hydroxypropyl-β-cyclodextrin (HPCD) and methyl-β-cyclodextrin (MCD) solutions were used for soil flushing in column test to evaluate some influent parameters that can significantly increase the removal efficiency. The process parameters chosen were CD concentration, ratio of washing solution volume to soil weight, and temperature of washing solution. These parameters were found to have a significant and almost linear effect on PAH removal from the contaminated soil, except the temperature where no significant enhancement in PAH extraction was observed for temperature range from 5 to 35 o C. The PAHs extraction enhancement factor compared to water was about 200. - An innovative method using a biodegradable and non-toxic flushing agent for the depollution of industrially aged-contaminated soil

  15. Impact of airflow interaction on inhaled air quality and transport of contaminants in rooms with personalized and total volume ventilation

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor; Cermak, Radim; Kovar, O.

    2003-01-01

    The impact of airflow interaction on inhaled air quality and transport of contaminants between occupants was studied in regard to pollution from floor covering, human bioeffluents and exhaled air, with combinations of two personalized ventilation systems (PV) with mixing and displacement...... quality with personalized and mixing ventilation was higher or at least similar compared to mixing ventilation alone. In the case of PV combined with displacement ventilation, the interaction caused mixing of the room air, an increase in the transport of bioeffluents and exhaled air between occupants and...... ventilation. In total, 80 L/s of clean air supplied at 20°C was distributed between the ventilation systems at different combinations of personalized airflow rate. Two breathing thermal manikins were used to simulate occupants in a full-scale test room. Regardless of the airflow interaction, the inhaled air...

  16. Applicability of the Linear Sorption Isotherm Model to Represent Contaminant Transport Processes in Site Wide Performance Assessments

    International Nuclear Information System (INIS)

    FOGWELL, T.W.; LAST, G.V.

    2003-01-01

    The estimation of flux of contaminants through the vadose zone to the groundwater under varying geologic, hydrologic, and chemical conditions is key to making technically credible and sound decisions regarding soil site characterization and remediation, single-shell tank retrieval, and waste site closures (DOE 2000). One of the principal needs identified in the science and technology roadmap (DOE 2000) is the need to improve the conceptual and numerical models that describe the location of contaminants today, and to provide the basis for forecasting future movement of contaminants on both site-specific and site-wide scales. The State of Knowledge (DOE 1999) and Preliminary Concepts documents describe the importance of geochemical processes on the transport of contaminants through the Vadose Zone. These processes have been identified in the international list of Features, Events, and Processes (FEPs) (NEA 2000) and included in the list of FEPS currently being developed for Hanford Site assessments (Soler et al. 2001). The current vision for Hanford site-wide cumulative risk assessments as performed using the System Assessment Capability (SAC) is to represent contaminant adsorption using the linear isotherm (empirical distribution coefficient, K d ) sorption model. Integration Project Expert Panel (PEP) comments indicate that work is required to adequately justify the applicability of the linear sorption model, and to identify and defend the range of K d values that are adopted for assessments. The work plans developed for the Science and Technology (S and T) efforts, SAC, and the Core Projects must answer directly the question of ''Is there a scientific basis for the application of the linear sorption isotherm model to the complex wastes of the Hanford Site?'' This paper is intended to address these issues. The reason that well documented justification is required for using the linear sorption (K d ) model is that this approach is strictly empirical and is often

  17. Aluminum-contaminant transport by surface runoff and bypass flow from an acid sulphate soil

    NARCIS (Netherlands)

    Minh, L.Q.; Tuong, T.P.; Mensvoort, van M.E.F.; Bouma, J.

    2002-01-01

    Quantifying the process and the amount of acid-contaminant released to the surroundings is important in assessing the environmental hazards associated with reclaiming acid sulphate soils (ASS). The roles of surface runoff and bypass flow (i.e. the rapid downward flow of free water along macropores

  18. Experimental study of contamination by inhalation of radioactive iodine aerosols. Biological balance; Etude experimentale de la contamination par inhalation d'aerosols d'iode radioactif bilan biologique

    Energy Technology Data Exchange (ETDEWEB)

    Marble, G [Commissariat a l' Energie Atomique, 92 - Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1968-07-01

    Several articles have been published concerning research into contamination produced by inhalation of radioactive iodine aerosols in monkeys. Results dealing with the biological balance of this contamination are presented and discussed in this report. (author) [French] L'etude experimentale de la contamination par inhalation d'aerosols d'iode radioactif effectuee chez le singe a fait l'objet de plusieurs publications. Les resultats concernant le bilan biologique de cette contamination sont presentes et discutes dans ce rapport. (auteur)

  19. A compartmentalized solute transport model for redox zones in contaminated aquifers: 1. Theory and development

    Science.gov (United States)

    Abrams , Robert H.; Loague, Keith

    2000-01-01

    This paper, the first of two parts [see Abrams and Loague, this issue], takes the compartmentalized approach for the geochemical evolution of redox zones presented by Abrams et al. [1998] and embeds it within a solute transport framework. In this paper the compartmentalized approach is generalized to facilitate the description of its incorporation into a solute transport simulator. An equivalent formulation is developed which removes any discontinuities that may occur when switching compartments. Rate‐limited redox reactions are modeled with a modified Monod relationship that allows either the organic substrate or the electron acceptor to be the rate‐limiting reactant. Thermodynamic constraints are used to inhibit lower‐energy redox reactions from occurring under infeasible geochemical conditions without imposing equilibrium on the lower‐energy reactions. The procedure used allows any redox reaction to be simulated as being kinetically limited or thermodynamically limited, depending on local geochemical conditions. Empirical reaction inhibition methods are not needed. The sequential iteration approach (SIA), a technique which allows the number of solute transport equations to be reduced, is adopted to solve the coupled geochemical/solute transport problem. When the compartmentalized approach is embedded within the SIA, with the total analytical concentration of each component as the dependent variable in the transport equation, it is possible to reduce the number of transport equations even further than with the unmodified SIA. A one‐dimensional, coupled geochemical/solute transport simulation is presented in which redox zones evolve dynamically in time and space. The compartmentalized solute transport (COMPTRAN) model described in this paper enables the development of redox zones to be simulated under both kinetic and thermodynamic constraints. The modular design of COMPTRAN facilitates the use of many different, preexisting solute transport and

  20. Preliminary description of hydrologic characteristics and contaminant transport potential of rocks in the Pasco Basin, south-central Washington

    International Nuclear Information System (INIS)

    Deju, R.A.; Fecht, K.R.

    1979-03-01

    This report aims at consolidating existing data useful in defining the hydrologic characteristics of the Pasco Basin within south-central Washington. It also aims at compiling the properties required to evaluate contaminant transport potential within individual subsurface strata in this basin. The Pasco Basin itself is a tract of semi-arid land covering about 2,000 square miles in south-central Washington. The regional geology of this basin is dominated by tholeiitic flood basalts of the Columbia Plateau. The surface hydrology of the basin is dominated by the Yakima, Snake, and Columbia rivers. Short-lived ephemeral streams may flow for a short period of time after a heavy rainfall or snowmelt. The subsurface hydrology of the Pasco Basin is characterized by an unconfined aquifer carrying the bulk of the water discharged within the basin. This aquifer overlies a series of confined aquifers carrying progressively smaller amounts of groundwater as a function of depth. The hydraulic properties of the various aquifers and non-water-bearing strata are characterized and reported. A summary of the basic properties is tabulated. The hydrochemical data obtained are summarized. The contaminant transport properties of the rocks in the Pasco Basin are analyzed with emphasis on the dispersion and sorption coefficients and the characteristics of the potential reactions between emplaced waste and the surrounding medium. Some basic modeling considerations of the hydrogeologic systems in the basin with a brief discussion of model input requirements and their relationship to available data are presented

  1. Unit environmental transport assessment of contaminants from Hanford's past-practice waste sites. Hanford Remedial Action Environmental Impact Statement

    International Nuclear Information System (INIS)

    Whelan, G.; Buck, J.W.; Castleton, K.J.

    1995-06-01

    The US Department of Energy, Richland Operations Office (DOE-RL) contracted Pacific Northwest Laboratory (PNL) to provide support to Advanced Sciences, Incorporated (ASI) in implementing tile regional no-action risk assessment in the Hanford Remedial Action Environmental Impact Statement. Researchers at PNL were charged with developing unit concentrations for soil, groundwater, surface water, and air at multiple locations within an 80-km radius from the center of tile Hanford installation. Using the Multimedia Environmental Pollutant Assessment System (MEPAS), PNL simulated (1) a unit release of one ci for each radionuclide and one kg for each chemical from contaminated soils and ponded sites, (2) transport of the contaminants in and through various environmental media and (3) exposure/risk of four exposure scenarios, outlined by the Hanford Site Baseline Remedial Action Methodology. These four scenarios include residential, recreational, industrial, and agricultural exposures. Spacially and temporally distributed environmental concentrations based on unit releases of radionuclides and chemicals were supported to ASI in support of the HRA-EIS. Risk for the four exposure scenarios, based on unit environment concentrations in air, water, and soil. were also supplied to ASI. This report outlines the procedure that was used to implement the unit transport portion of the HRA-EIS baseline risk assessment. Deliverables include unit groundwater, surface water, air, and soil concentrations at multiple locations within an 80-km radius from the center of the Hanford installation

  2. Modeling Human Nonalcoholic Steatohepatitis-Associated Changes in Drug Transporter Expression Using Experimental Rodent Models

    OpenAIRE

    Canet, Mark J.; Hardwick, Rhiannon N.; Lake, April D.; Dzierlenga, Anika L.; Clarke, John D.; Cherrington, Nathan J.

    2014-01-01

    Nonalcoholic fatty liver disease is a prevalent form of chronic liver disease that can progress to the more advanced stage of nonalcoholic steatohepatitis (NASH). NASH has been shown to alter drug transporter regulation and may have implications in the development of adverse drug reactions. Several experimental rodent models have been proposed for the study of NASH, but no single model fully recapitulates all aspects of the human disease. The purpose of the current study was to determine whic...

  3. A chromate-contaminated site in southern Switzerland – Part 2: Reactive transport modeling to optimize remediation options

    International Nuclear Information System (INIS)

    Wanner, Christoph; Eggenberger, Urs; Mäder, Urs

    2012-01-01

    A 2D horizontal reactive transport model of a chromate-contaminated site near Rivera, Switzerland, was developed using the computer code CrunchFlow to evaluate site remediation strategies. Transport processes were defined according to the results of an existing hydrological model, and the definition of geochemical (reactive) processes is based on the results of a detailed mineralogical and geochemical site characterization leading to a comprehensive conceptual site model. Kinetics of naturally occurring Cr(VI) reduction by Fe(II) and natural solid organic matter is quantified by fitting measured Cr isotope ratios to a modeled 1D section along the best constrained flow line. The simulation of Cr isotope fractionation was also incorporated into the 2D model. Simulation of the measured present day Cr(VI) plume and δ 53 Cr value distribution was used for the 2D model calibration and corresponds to a situation where only monitored natural attenuation (MNA) is occurring. Other 2D model runs simulate alternate excavation scenarios. The simulations show that with an excavation of the top 2–4 m the groundwater Cr(VI) plume can be minimized, and that a deeper excavation depth only diminishes the plume if all the contaminants can be removed. A combination of an excavation of the top 2–4 m and monitoring of the ongoing natural Cr(VI) reduction is suggested as the most ecological and economical remediation strategy, even though a remaining time period with ongoing subsoil Cr(VI) contamination in the order of 1 ka is predicted.

  4. Numerical simulation of seasonal heat storage in a contaminated shallow aquifer - Temperature influence on flow, transport and reaction processes

    Science.gov (United States)

    Popp, Steffi; Beyer, Christof; Dahmke, Andreas; Bauer, Sebastian

    2015-04-01

    The energy market in Germany currently faces a rapid transition from nuclear power and fossil fuels towards an increased production of energy from renewable resources like wind or solar power. In this context, seasonal heat storage in the shallow subsurface is becoming more and more important, particularly in urban regions with high population densities and thus high energy and heat demand. Besides the effects of increased or decreased groundwater and sediment temperatures on local and large-scale groundwater flow, transport, geochemistry and microbiology, an influence on subsurface contaminations, which may be present in the urban surbsurface, can be expected. Currently, concerns about negative impacts of temperature changes on groundwater quality are the main barrier for the approval of heat storage at or close to contaminated sites. The possible impacts of heat storage on subsurface contamination, however, have not been investigated in detail yet. Therefore, this work investigates the effects of a shallow seasonal heat storage on subsurface groundwater flow, transport and reaction processes in the presence of an organic contamination using numerical scenario simulations. A shallow groundwater aquifer is assumed, which consists of Pleistoscene sandy sediments typical for Northern Germany. The seasonal heat storage in these scenarios is performed through arrays of borehole heat exchangers (BHE), where different setups with 6 and 72 BHE, and temperatures during storage between 2°C and 70°C are analyzed. The developing heat plume in the aquifer interacts with a residual phase of a trichloroethene (TCE) contamination. The plume of dissolved TCE emitted from this source zone is degraded by reductive dechlorination through microbes present in the aquifer, which degrade TCE under anaerobic redox conditions to the degradation products dichloroethene, vinyl chloride and ethene. The temperature dependence of the microbial degradation activity of each degradation step is

  5. Estimation of transport parameters of phenolic compounds and inorganic contaminants through composite landfill liners using one-dimensional mass transport model

    International Nuclear Information System (INIS)

    Varank, Gamze; Demir, Ahmet; Yetilmezsoy, Kaan; Bilgili, M. Sinan; Top, Selin; Sekman, Elif

    2011-01-01

    Highlights: → We conduct 1D advection-dispersion modeling to estimate transport parameters. → We examine fourteen phenolic compounds and three inorganic contaminants. → 2-MP, 2,4-DCP, 2,6-DCP, 2,4,5-TCP, 2,3,4,6-TeCP have the highest coefficients. → Dispersion coefficients of Cu are determined to be higher than Zn and Fe. → Transport of phenolics can be prevented by zeolite and bentonite in landfill liners. - Abstract: One-dimensional (1D) advection-dispersion transport modeling was conducted as a conceptual approach for the estimation of the transport parameters of fourteen different phenolic compounds (phenol, 2-CP, 2-MP, 3-MP, 4-MP, 2-NP, 4-NP, 2,4-DNP, 2,4-DCP, 2,6-DCP, 2,4,5-TCP, 2,4,6-TCP, 2,3,4,6-TeCP, PCP) and three different inorganic contaminants (Cu, Zn, Fe) migrating downward through the several liner systems. Four identical pilot-scale landfill reactors (0.25 m 3 ) with different composite liners (R1: 0.10 + 0.10 m of compacted clay liner (CCL), L e = 0.20 m, k e = 1 x 10 -8 m/s, R2: 0.002-m-thick damaged high-density polyethylene (HDPE) geomembrane overlying 0.10 + 0.10 m of CCL, L e = 0.20 m, k e = 1 x 10 -8 m/s, R3: 0.002-m-thick damaged HDPE geomembrane overlying a 0.02-m-thick bentonite layer encapsulated between 0.10 + 0.10 m CCL, L e = 0.22 m, k e = 1 x 10 -8 m/s, R4: 0.002-m-thick damaged HDPE geomembrane overlying a 0.02-m-thick zeolite layer encapsulated between 0.10 + 0.10 m CCL, L e = 0.22 m, k e = 4.24 x 10 -7 m/s) were simultaneously run for a period of about 540 days to investigate the nature of diffusive and advective transport of the selected organic and inorganic contaminants. The results of 1D transport model showed that the highest molecular diffusion coefficients, ranging from 4.77 x 10 -10 to 10.67 x 10 -10 m 2 /s, were estimated for phenol (R4), 2-MP (R1), 2,4-DNP (R2), 2,4-DCP (R1), 2,6-DCP (R2), 2,4,5-TCP (R2) and 2,3,4,6-TeCP (R1). For all reactors, dispersion coefficients of Cu, ranging from 3.47 x 10 -6 m 2 /s to 5

  6. Evaluation of modeling approaches to simulate contaminant transport in a fractured limestone aquifer

    DEFF Research Database (Denmark)

    Mosthaf, Klaus; Fjordbøge, Annika Sidelmann; Broholm, Mette Martina

    in fractured limestone aquifers. The model comparison is conducted for a contaminated site in Denmark, where a plume of dissolved PCE has migrated through a fractured limestone aquifer. Field data includes information on spill history, distribution of the contaminant (multilevel sampling), geology...... and hydrogeology. To describe the geology and fracture system, data from borehole logs and cores was combined with an analysis of heterogeneities and fractures from a nearby excavation and pump test data. We present how field data is integrated into the different model concepts. A challenge in the use of field...... and remediation strategies. Each model is compared with field data, considering both model fit and model suitability. Results show a considerable difference between the approaches, and that it is important to select the right one for the actual modeling purpose. The comparison with data showed how much...

  7. Monte Carlo simulation of radioactive contaminant transport in unsaturated porous media

    International Nuclear Information System (INIS)

    Giacobbo, F.; Patelli, E.; Zio, E.

    2005-01-01

    In the current proposed solutions of radioactive waste repositories, the protective function against the radionuclide water-driven transport back to the biosphere is to be provided by an integrated system of artificial and natural geologic barriers. The complexity of the transport process in the barriers' heterogeneous media forces approximations to the classical analytical-numerical models, thus reducing their adherence to reality. In an attempt to overcome these difficulties, in the present paper we adopt a Monte Carlo simulation approach, previously developed on the basis of the Kolmogorov and Dmitriev theory of branching stochastic processes. The approach is here extended for describing transport through unsaturated porous media under unsteady flow conditions. This generalization entails the determination of the functional dependence of the parameters of the proposed transport model from the water content, which changes in space and time during the water infiltration process. The approach is verified with respect to a case of non-reactive transport under transient unsaturated field conditions by a comparison with a standard code based on the classical advection-dispersion equations. An application regarding linear reactive transport is then presented. (authors)

  8. Dose reconstruction in radioactively contaminated areas based on radiation transport calculations and measurements

    International Nuclear Information System (INIS)

    Hiller, Mauritius Michael

    2015-01-01

    The external radiation exposure at the former village of Metlino, Russia, was reconstructed. The Techa river in Metlino was contaminated by water from the Majak plant. The village was evacuated in 1956 and a reservoir lake created. Absorbed doses in bricks were measured and a model of the present-day and the historic Metlino was created for Monte Carlo calculations. By combining both, the air kerma at shoreline could be reconstructed to evaluate the Techa River Dosimetry System.

  9. A chaotic-dynamical conceptual model to describe fluid flow and contaminant transport in a fractured vadose zone. 1997 progress report and presentations at the annual meeting, Ernest Orlando Lawrence Berkeley National Laboratory, December 3-4, 1997

    International Nuclear Information System (INIS)

    Faybishenko, B.; Doughty, C.; Geller, J.

    1998-07-01

    Understanding subsurface flow and transport processes is critical for effective assessment, decision-making, and remediation activities for contaminated sites. However, for fluid flow and contaminant transport through fractured vadose zones, traditional hydrogeological approaches are often found to be inadequate. In this project, the authors examine flow and transport through a fractured vadose zone as a deterministic chaotic dynamical process, and develop a model of it in these terms. Initially, the authors examine separately the geometric model of fractured rock and the flow dynamics model needed to describe chaotic behavior. Ultimately they will put the geometry and flow dynamics together to develop a chaotic-dynamical model of flow and transport in a fractured vadose zone. They investigate water flow and contaminant transport on several scales, ranging from small-scale laboratory experiments in fracture replicas and fractured cores, to field experiments conducted in a single exposed fracture at a basalt outcrop, and finally to a ponded infiltration test using a pond of 7 by 8 m. In the field experiments, they measure the time-variation of water flux, moisture content, and hydraulic head at various locations, as well as the total inflow rate to the subsurface. Such variations reflect the changes in the geometry and physics of water flow that display chaotic behavior, which they try to reconstruct using the data obtained. In the analysis of experimental data, a chaotic model can be used to predict the long-term bounds on fluid flow and transport behavior, known as the attractor of the system, and to examine the limits of short-term predictability within these bounds. This approach is especially well suited to the need for short-term predictions to support remediation decisions and long-term bounding studies. View-graphs from ten presentations made at the annual meeting held December 3--4, 1997 are included in an appendix to this report

  10. A laboratory based experimental study of mercury emission from contaminated soils in the River Idrijca catchment

    Directory of Open Access Journals (Sweden)

    D. Kocman

    2010-02-01

    Full Text Available Results obtained by a laboratory flux measurement system (LFMS focused on investigating the kinetics of the mercury emission flux (MEF from contaminated soils of the Idrija Hg-mine region, Slovenia are presented. Representative soil samples with respect to total Hg concentrations (4–417 μg g−1 and land cover (forest, meadow and alluvial soil alongside the River Idrijca were analysed to determine the variation in MEF versus distance from the source, regulating three major environmental parameters comprising soil temperature, soil moisture and solar radiation. MEFs ranged from less than 2 to 530 ng m−2 h−1, with the highest emissions from contaminated alluvial soils and soils near the mining district in the town of Idrija. A significant decrease of MEF was then observed with increasing distance from these sites. The results revealed a strong positive effect of all three parameters investigated on momentum MEF. The light-induced flux was shown to be independent of the soil temperature, while the soil aqueous phase seems to be responsible for recharging the pool of mercury in the soil available for both the light- and thermally-induced flux. The overall flux response to simulated environmental conditions depends greatly on the form of Hg in the soil. Higher activation energies are required for the overall process to occur in soils where insoluble cinnabar prevails compared to soils where more mobile Hg forms and forms available for transformation processes are dominant.

  11. Effectiveness of ceramic filters in capturing Giardia duodenalis cysts in experimentally contaminated water

    Directory of Open Access Journals (Sweden)

    Larissa Imaculada da Costa Sobrinho

    2016-04-01

    Full Text Available Giardia duodenalis is the main water-transmitted protozoan in developing countries. This study evaluated the effectiveness of ceramic filters in capturing G. duodenalis cysts and verified the porosity size needed to remove cysts from contaminated water. The study was conducted in the Laboratory of Parasitology at the University of Taubaté, where each filter unit was made by joining two Pet gallons, latex hose and a ceramic filter. Two porosity sizes were selected: 0.5-1.0 μm and 5-15 μm with or without activated carbon, and the assays were run in triplicate. Approximately 60 μL (53 cysts of G. duodenalis cysts were placed in 2 liters of distilled water. After the preparation of the contaminated water, this solution was run through the filter until the completely filtered. Afterwards, the filtrate was processed according to the methodology described by De Faria (2006, in order to concentrate parasitic elements. The results were statistically evaluated using ANOVA and Tukey tests, showing that the 0.5- 1,0 μm porosity filter candles (with and without activated carbon were able to retain 100% of cysts of G. duodenalis. This is a result significantly superior to the results obtained in the control group (p<0.05. On the other hand, for the candles with porosity of 5 15 μm, total retention occurred only in candles with activated carbon. Based upon our results, it can be concluded that, in candles with both porosity sizes with activated carbon, all filters showed a satisfactory efficacy for filtration of G. duodenalis cysts.

  12. Experimental study on unsteady open channel flow and bedload transport based on a physical model

    Science.gov (United States)

    Cao, W.

    2015-12-01

    Flow in a nature river are usually unsteady, while nearly all the theories about bedload transport are on the basis of steady, uniform flow, and also with supposed equilibrium state of sediment transport. This is may be one of the main reasons why the bedload transport formulas are notoriously poor accuracy to predict the bedload. The aim of this research is to shed light on the effect of unsteadiness on the bedload transport based on experimental studies. The novel of this study is that the experiments were not carried out in a conventional flume but in a physical model, which are more similar to the actual river. On the other hand, in our experiments, multiple consecutive flood wave were reproduced in the physical model, and all the flow and sediment parameters are based on a large number of data obtained from many of identical flood waves. This method allow us to get more data for one flood, efficiently avoids the uncertainty of bedload rate only for one single flood wave, due to the stochastic fluctuation of the bedload transport. Three different flood waves were selected in the experiments. During each run of experiment, the water level of five different positions along the model were measured by ultrasonic water level gauge, flow velocity at the middle of the channel were measured by two dimensional electromagnetic current meter. Moreover, the bedload transport rate was measured by a unique automatic trap collecting and weighing system at the end of the physical model. The results shows that the celerity of flood wave propagate varies for different flow conditions. The velocity distribution was approximately accord with log-law profile during the entire rising and falling limb of flood. The bedload transport rate show intensity fluctuation in all the experiments, moreover, for different flood waves, the moment when the shear stress reaches its maximum value is not the exact moment when the sediment transport rate reaches its maximum value, which indicates

  13. Catchment-scale contaminant transport under changing hydro-climatic conditions in the Aral Sea Drainage Basin, Central Asia

    Science.gov (United States)

    Jarsjö, Jerker; Törnqvist, Rebecka; Su, Ye

    2013-04-01

    Dependable projections of future water availability and quality are essential in the management of water resources. Changes in land use, water use and climate can have large impacts on water and contaminant flows across extensive catchments that may contain different administrative regions where shared water resources must be managed. We consider the extensive Aral Sea Drainage Basin (ASDB) and the Amu Darya River Delta in Central Asia, which are currently under severe water stress due to large-scale irrigation expansion. We interpret data on hydro-climatic conditions, main contaminants of surface water and shallow groundwater systems, location of rivers and canal networks, and groundwater flow directions. The data are used together with climate change projections from general circulation models (GCMs) as input to hydrological and (advective) transport modelling. The main goal is to assess how regional transport pathways and travel times have changed, and are likely to change further, in response to past and projected future hydro-climatic changes. More specifically, the hydrological modelling was based on temperature and precipitation change (ΔT and ΔP) results from 65 GCM projections of 21st century conditions (specifically considering time periods around 2025, 2050, and 2100), relative to reference conditions around 1975 (taken from the reference period 1961-1990). Whereas ΔT is robustly projected to increase with time, the projected magnitude of ΔP differs more among projections for the distant future (2100) than for the near future (2025), with uncertainty remaining even about the direction of change (i.e., positive or negative ΔP). However, mainly due to the projected temperature-driven increases in evapotranspiration, ensemble average results show that the Amu Darya river discharge Q in the downstream ASDB is likely to show a decreasing trend throughout the 21st century. Notably, projected changes in the upstream, mountainous regions have a relatively

  14. Grand challenge problems in environmental modeling and remediation: Groundwater contaminant transport. Final project report 1998

    International Nuclear Information System (INIS)

    1998-04-01

    The over-reaching goal of the Groundwater Grand Challenge component of the Partnership in Computational Science (PICS) was to develop and establish the massively parallel approach for the description of groundwater flow and transport and to address the problem of uncertainties in the data and its interpretation. This necessitated the development of innovative algorithms and the implementation of massively parallel computational tools to provide a suite of simulators for groundwater flow and transport in heterogeneous media. This report summarizes the activities and deliverables of the Groundwater Grand Challenge project funded through the High Performance Computing grand challenge program of the Department of Energy from 1995 through 1997

  15. Annotated bibliography of literature relating to wind transport of plutonium-contaminated soils at the Nevada Test Site

    International Nuclear Information System (INIS)

    Lancaster, N.; Bamford, R.

    1993-12-01

    During the period from 1954 through 1963, a number of tests were conducted on the Nevada Test Site (NTS) and Tonopah Test Range (TTR) to determine the safety of nuclear devices with respect to storage, handling, transport, and accidents. These tests were referred to as ''safety shots.'' ''Safety'' in this context meant ''safety against fission reaction.'' The safety tests were comprised of chemical high explosive detonations with components of nuclear devices. The conduct of these tests resulted in the dispersion of plutonium, and some americium over areas ranging from several tens to several hundreds of hectares. Of the various locations used for safety tests, the site referred to as ''Plutonium Valley'' was subject to a significant amount of plutonium contamination. Plutonium Valley is located in Area 11 on the eastern boundary of the NTS at an elevation of about 1036 m (3400 ft). Plutonium Valley was the location of four safety tests (A,B,C, and D) conducted during 1956. A major environmental, health, and safety concern is the potential for inhalation of Pu 239,240 by humans as a result of airborne dust containing Pu particles. Thus, the wind transport of Pu 239,240 particles has been the subject of considerable research. This annotated bibliography was created as a reference guide to assist in the better understanding of the environmental characteristics of Plutonium Valley, the safety tests performed there, the processes and variables involved with the wind transport of dust, and as an overview of proposed clean-up procedures

  16. Induced Environment Contamination Monitor (IECM), air sampler - Results from the Space Transport System (STS-2) flight

    Science.gov (United States)

    Peters, P. N.; Hester, H. B.; Bertsch, W.; Mayfield, H.; Zatko, D.

    1983-01-01

    An investigation involving sampling the rapidly changing environment of the Shuttle cargo bay is considered. Four time-integrated samples and one rapid acquisition sample were collected to determine the types and quantities of contaminants present during ascent and descent of the Shuttle. The sampling times for the various bottles were controlled by valves operated by the Data Acquisition and Control System (DACS) of the IECM. Many of the observed species were found to be common solvents used in cleaning surfaces. When the actual volume sampled is taken into account, the relative mass of organics sampled during descent is about 20 percent less than during ascent.

  17. A Generalized Model for Transport of Contaminants in Soil by Electric Fields

    DEFF Research Database (Denmark)

    Paz-Garcia, Juan Manuel; Baek, Kitae; Alshawabkeh, Iyad D.

    2012-01-01

    with geochemical reactions such as aqueous equilibrium, sorption, precipitation and dissolution. The enhanced model is used to simulate electrokinetic cleanup of lead and copper contaminants at an Army Firing Range. Acid enhancement is achieved by the use of adipic acid to neutralize the basic front produced...... for the cathode electrochemical reaction. The model is able to simulate enhanced application of the process by modifying the boundary conditions. The model showed that kinetics of geochemical reactions, such as metals dissolution/leaching and redox reactions might be significant for realistic prediction...... of enhanced electrokinetic extraction of metals in real world applications....

  18. Numerical Survey of Contaminant Transport and Self-Cleansing of Water in Nador Lagoon, Morocco

    Directory of Open Access Journals (Sweden)

    E. M. Chaabelasri

    2014-01-01

    Full Text Available Numerical simulations are presented of the flow hydrodynamics and hypothetical contaminant dispersion patterns in Nador Lagoon, a shallow lagoon with a barrier island situated on the coast of Morocco. It is found that the natural circulation forced by the tidal flow in the lagoon is greatly affected by the development of an artificial inlet in the barrier island. The case study demonstrates the potential use of modern computational hydraulics as a tool integrated in the decision support system designed to manage a lagoon ecosystem.

  19. Source water assessment and nonpoint sources of acutely toxic contaminants: A review of research related to survival and transport of Cryptosporidium parvum

    Science.gov (United States)

    Walker, Mark J.; Montemagno, Carlo D.; Jenkins, Michael B.

    1998-12-01

    Amendments to the Safe Drinking Water Act (PL-930123) in 1996 required that public water supply managers identify potential sources of contamination within contributing areas. Nonpoint sources of acutely toxic microbial contaminants, such as Cryptosporidium parvum, challenge current approaches to source identification and management as a first step toward developing management plans for public water supply protection. Little may be known about survival and transport in the field environment, prescribed practices may not be designed to manage such substances, and infective stages may be present in vast numbers and may resist water treatment and disinfection processes. This review summarizes research related to survival and transport of C. parvum oocysts, as an example of an acutely toxic contaminant with nonpoint sources in animal agriculture. It discusses ∥1) significance of infected domesticated animals as potential sources of C. parvum, (2) laboratory and field studies of survival and transport, and (3) approaches to source control in the context of public health protection.

  20. Experimental contamination of margaritana margaritifera (L) (a Fresh water bivalve) by caesium 137; Contamination experimentale de margaritana margaritifera (L) (bivalve d'eau douce) par le cesium 137

    Energy Technology Data Exchange (ETDEWEB)

    Foulquier, L; Bovard, P; Grauby, A [Commissariat a l' Energie Atomique, Cadarache (France). Centre d' Etudes Nucleaires

    1966-07-01

    The hydro biological research carried out in the Radio-Ecology Section has led the authors to study some Margaritana sampling stations situated down-stream from the Monts d'Arree nuclear power station. They describe the preservation and contamination methods used for fixing the {sup 137}Cs concentration factors in the case of Margaritana Margaritifera (L). The results of experiments carried out over a period of one hundred days show that the specific activity of the various organs is stabilized after thirty to thirty-five days. The authors have noticed a relatively low adsorption on the shell through the intermediary of micro-organisms, and a strong and rapid absorption in the soft parts. The concentration factors have values, at equilibrium, of around: 9 for the shell, 300 for all the organs, and 38 for the whole animal. A comparison of these results with work published by other authors makes it possible to draw general conclusions concerning the mechanism of {sup 137}Cs fixation by lamellibranch, as well as their capacity of fixation. (author) [French] Les etudes hydrobiologiques effectuees au sein de la Section de Radio-Ecologie ont amene les auteurs a etudier des stations de prelevement de Margaritana en aval de la Centrale Nucleaire des Monts d'Arree. Ils decrivent les methodes de conservation et de contamination utilisees pour l'etablissement des facteurs de concentration du {sup 137}Cs par Margaritana margaritifera (L). Les resultats des experimentations menees pendant cent jours montrent que les activites specifiques de la coquille et des differents organes se stabilisent au bout de trente a trente-cinq jours. Les auteurs constatent une adsorption relativement faible sur la coquille par l'intermediaire des micro-organismes et une absorption forte et rapide dans les parties molles. Les facteurs de concentration se situent, a l'equilibre, autour de: 9 pour la coquille, 300 pour l'ensemble des organes et 38 si l'on considere l'animal total. Cette etude

  1. Existing experimental criticality data applicable to nuclear-fuel-transportation systems

    International Nuclear Information System (INIS)

    Bierman, S.R.

    1983-02-01

    Analytical techniques are generally relied upon in making criticality evaluations involving nuclear material outside reactors. For these evaluations to be accepted the calculations must be validated by comparison with experimental data for a known set of conditions having physical and neutronic characteristics similar to those conditions being evaluated analytically. The purpose of this report is to identify those existing experimental data that are suitable for use in verifying criticality calculations on nuclear fuel transportation systems. In addition, near term needs for additional data in this area are identified. Of the considerable amount of criticality data currently existing, that are applicable to non-reactor systems, those particularly suitable for use in support of nuclear material transportation systems have been identified and catalogued into the following groups: (1) critical assemblies of fuel rods in water; (2) critical assemblies of fuel rods in water containing soluble neutron absorbers; (3) critical assemblies containing solid neutron absorber; (4) critical assemblies of fuel rods in water with heavy metal reflectors; and (5) critical assemblies of fuel rods in water with irregular features. A listing of the current near term needs for additional data in each of the groups has been developed for future use in planning criticality research in support of nuclear fuel transportation systems. The criticality experiments needed to provide these data are briefly described and identified according to priority and relative cost of performing the experiments

  2. Heterogeneity and contaminant transport modeling for the Savannah River integrated demonstration site

    International Nuclear Information System (INIS)

    Chesnut, D.A.

    1992-11-01

    The effectiveness of remediating aquifers and vadose zone sediments is frequently controlled by spatial heterogeneities. A continuing and long-recognized problem in selecting, planning, implementing, and operating remediation projects is the development of methods for quantitatively describing heterogeneity and predicting its effects on process performance. The similarity to and differences from modeling oil recovery processes in the petroleum industry are illustrated by the extension to contaminant extraction processes of an analytic model originally developed for waterflooding petroleum reservoirs. The resulting equations incorporate the effects of heterogeneity through a single parameter, σ. Fitting this model to the Savannah River in situ Air Stripping test data suggests that the injection of air into a horizontal well below the water table may have improved performance by changing the flow pattern in the vadose zone. This change increased the capture volume, and consequently the contaminant mass inventory, of the horizontal injection well completed in the vadose zone. The apparent increases (compared to extraction only from the horizontal well) are from 10,200 to 21,000 pounds for TCE and from 3,600 pounds to 59,800 pounds for PCE. The predominance of PCE in this calculated increase suggests that redistribution of flow paths in the vadose zone, rather than in-situ stripping, may provide most of the improvement. Although this preliminary conclusion remains to be reinforced by more sophisticated modeling currently in progress, there appears to be a definite improvement, which is attributable to air injection, over conventional remediation methods

  3. The problem of radioactive contamination inhomogeneity and simulation of the transport of radionuclides through agroecosystems

    International Nuclear Information System (INIS)

    Girij, V.A.; Shpinar, L.I.; Yaskovets, I.I.; Zaitov, V.R.; Hille, R.

    1997-01-01

    The analyses of the measurement data on the territory of the Ukrainian Polesie region carried out by the Research Centre Juelich and the Ukrainian Institute of Radioecology shows that there is a high degree of inhomogeneity for the contamination pattern, they transfer from soil to the biosphere and for the food consumption. Therefore, a deterministic environmental assessment model may not be convenient because most processes are not known in detailed. In this situation a probabilistic approach seems to be more promising. In this report presented a dynamic model for the transfer of radioactivity in terrestrial food chains that fit to the regionally conditions and agricultural practice. The living organism will be treated as dynamic system subject to random action of radioactivity. This system is described by stochastic differential equations of Langevene's type. Starting from this base we calculated a distribution function of radionuclide body burdens for inhabitant ensembles under the assumptions that entering of activity into organisms is a random temporary function that can be approximated by certain impulse Poison processes. A comparison of calculated distribution function is carried out with measurement results of internal body burden. It shown a satisfactory description of the real situation found for four investigated villages of Ukrainian Polesie region (Olevsk, Narodichi, Vezhitsa and Stare Selo) that were characterized by different degree of contamination and different degree of inhomogeneity

  4. Summary of Vadose -- Zone Conceptual Models for Flow and Contaminant Transport and 1999 - 2003 Progress on Resolving Deficiencies in Understanding the Vadose Zone at the INEEL

    Energy Technology Data Exchange (ETDEWEB)

    Robert C. Starr; Dana L. Dettmers; Brennon R. Orr; Thomas R. Wood

    2003-12-01

    The thick vadose zone that underlies the Idaho National Engineering and Environmental Laboratory has been recognized both as an avenue through which contaminants disposed at or near the ground surface can migrate to groundwater in the underlying Eastern Snake River Plain aquifer, and as a barrier to the movement of contaminants into the aquifer. Flow and contaminant transport in the vadose zone at the INEEL is complicated by the highly heterogeneous nature of the geologic framework and by the variations in the behavior of different contaminants in the subsurface. The state of knowledge concerning flow and contaminant transport in the vadose zone at and near the INEEL IN 1999 was summarized in Deficiencies in Vadose Zone Understanding at the Idaho National Engineering and Environmental Laboratory (Wood et al., 2000). These authors identified deficiencies in knowledge of flow and contaminant transport processes in the vadose zone, and provided recommendations for additional work that should be conducted to address these deficiencies. In the period since (Wood et al., 2000) was prepared, research has been published that, to some degree, address these deficiencies. This document provides a bibliography of reports, journal articles, and conference proceedings published 1999 through mid-2003 that are relevant to the vadose zone at or near the INEEL and provides a brief description of each work. Publications that address specific deficiencies or recommendations are identified, and pertinent information from selected publications is presented.

  5. Transport of microbial tracers in clean and organically contaminated silica sand in laboratory columns compared with their transport in the field

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, Louise, E-mail: louise.weaver@esr.cri.nz; Sinton, Lester W.; Pang, Liping; Dann, Rod; Close, Murray

    2013-01-15

    Waste disposal on land and the consequent transport of bacterial and viral pathogens in soils and aquifers are of major concern worldwide. Pathogen transport can be enhanced in the presence of organic matter due to occupation of attachment sites in the aquifer materials thus preventing pathogen attachment leading to their faster transport for longer distances. Laboratory column studies were carried out to investigate the effect of organic matter, in the form of dissolved organic carbon (DOC), on the transport of Escherichia coli and MS2 phage in saturated clean silica sand. Transport rates of these microbial tracers were also studied in a contaminated field site. Laboratory column studies showed that low concentrations (0.17 mg L{sup −1}) of DOC had little effect on E. coli J6-2 removal and slightly reduced the attachment of MS2 phage. After progressive conditioning of the column with DOC (1.7 mg L{sup −1} and 17 mg L{sup −1}), neither E. coli J6-2 nor MS2 phage showed any attachment and recovery rates increased dramatically (up to 100%). The results suggest that DOC can affect the transport rates of microbial contaminants. For E. coli J6-2 the predominant effect appeared to be an increase in the secondary energy minimum leading to an increase in E. coli attachment initially. However, after 17 mg L{sup −1} DOC conditioning of the silica sand no attachment of E. coli was observed as the DOC took up attachment sites in the porous media. MS2 phage appeared to be affected predominantly by out-competition of binding sites in the clean silica sand and a steady reduction in attachment was observed as the DOC conditioning increased. Field study showed a high removal of both E. coli and MS2 phage, although E. coli was removed at a lower rate than MS2 phage. In the field it is likely that a combination of effects are seen as the aquifer material will be heterogeneous in its surface nanoscale properties, demonstrated by the differing removal of E. coli and MS2 phage

  6. Toxoplasma gondii transmission by artificial insemination in sheep with experimentally contaminated frozen semen.

    Science.gov (United States)

    Consalter, Angélica; Silva, Andressa F; Frazão-Teixeira, Edwards; Matos, Luis F; de Oliveira, Francisco C R; Leite, Juliana S; Silva, Franciele B F; Ferreira, Ana M R

    2017-03-01

    Toxoplasma gondii is a parasite considered one of the major causes of reproductive problems in sheep. Furthermore, the presence of the agent in ram semen urges the possibility of sexual transmission in this species. The aim of this study was to evaluate if ram's frozen semen spiked with T. gondii tachyzoites would be able to cause infection in sheep by laparoscopic artificial insemination (AI). Nine ewes tested seronegative to anti-T. gondii antibodies by the modified agglutination test (MAT) were superovulated and inseminated to collect embryos. Animals were divided into two groups: G1 (n = 5), ewes inseminated with semen containing 4 × 10 7 tachyzoites; and G2 (n = 4), ewes inseminated with tachyzoite-free semen (control group). To confirm infection, ewe's blood samples were collected on days -14, -7, 0, 7, 14, 21, 28, 35, 49 and 57 after AI for analysis by MAT and PCR. Tissue samples of these ewes were also collected for histopathology and immunohistochemistry (IHC). Seven days after AI, all ewes of group G1 had specific antibodies to T. gondii, while those of G2 were negative. Toxoplasma gondii DNA was detected in the blood of one ewe and parasites were observed in tissues of all five animals inseminated with contaminated semen, indicating that semen freezing protocol does not affect T. gondii transmission by artificial insemination in sheep. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Experimental contamination of margaritana margaritifera (L) (a Fresh water bivalve) by caesium 137

    International Nuclear Information System (INIS)

    Foulquier, L.; Bovard, P.; Grauby, A.

    1966-01-01

    The hydro biological research carried out in the Radio-Ecology Section has led the authors to study some Margaritana sampling stations situated down-stream from the Monts d'Arree nuclear power station. They describe the preservation and contamination methods used for fixing the 137 Cs concentration factors in the case of Margaritana Margaritifera (L). The results of experiments carried out over a period of one hundred days show that the specific activity of the various organs is stabilized after thirty to thirty-five days. The authors have noticed a relatively low adsorption on the shell through the intermediary of micro-organisms, and a strong and rapid absorption in the soft parts. The concentration factors have values, at equilibrium, of around: 9 for the shell, 300 for all the organs, and 38 for the whole animal. A comparison of these results with work published by other authors makes it possible to draw general conclusions concerning the mechanism of 137 Cs fixation by lamellibranch, as well as their capacity of fixation. (author) [fr

  8. Experimental and gyrokinetic investigation of core impurity transport in Alcator C-mod

    Science.gov (United States)

    Howard, N.; Greenwald, M.; Podpaly, Y.; Reinke, M. L.; Rice, J. E.; White, A. E.; Mikkelsen, D. R.; Puetterich, T.

    2010-11-01

    A new multiple pulse laser blow-off system coupled with an upgraded high resolution x-ray spectrometer with spatial resolution allow for the most detailed studies of impurity transport on Alcator C-mod to date. Trace impurity injections created by the laser blow-off technique were introduced into plasmas with a wide range of parameters and time evolving profiles of He-like calcium were measured. The unique measurement of a single charge state profile and line integrated emission measurements from spectroscopic diagnostics were compared with the simulated emission from the impurity transport code STRAHL. A nonlinear least squares fitting routine was coupled with STRAHL, allowing for core impurity transport coefficients with errors to be determined. With this method, experimental data from trace calcium injections were analyzed and radially dependent, core values (< r/a ˜.6) of the diffusive and convective components of the impurity flux were obtained. The STRAHL results are compared with linear and global, nonlinear simulations from the gyrokinetic code GYRO. Results of this comparison and an investigation of the underlying physics associated with turbulent impurity transport will be presented.

  9. Selective segmental sclerotherapy of the liver by transportal absolute ethanol injection: an animal experimental study

    International Nuclear Information System (INIS)

    Pan Jie; Yang Ning; Zhang Zhongzhong; Hu Libin; Chen Jie; Wu Wei; Jin Zhengyu; Liu Wei

    2003-01-01

    Objective: To evaluate the safety and efficacy of selective segmental sclerotherapy (SSS) of the liver by transportal absolute ethanol injection with an animal experimental study, and to discuss several technical points involved in this method. Methods: Thirty dogs received SSS of the liver by transportal absolute ethanol injection with the injection dose of 0.2-1.0 ml/kg, repeated examinations of blood ethanol level, WBC, and liver functions were done, and CT and pathological examinations of the liver were performed. Results: All dogs treated with SSS survived during the study. The maximum elevation of blood ethanol values occurred in group F. Its average value was (1.603 ± 0.083) mg/ml, which was much lower than that of death level. Transient elevations of blood WBC and ALT were seen. The average values of WBC and ALT were (46.36 ± 7.28) x 10 9 and (827.36 ± 147.25) U/L, respectively. CT and pathological examinations proved that the dogs given SSS by transportal absolute ethanol injection with the injection dose of 0.3-1.0 ml/kg had a complete wedge-shaped necrosis in the liver. Conclusion: Selective segmental sclerotherapy of the liver by transportal ethanol injection was quite safe and effective if the proper dose of ethanol was injected. SSS may be useful in the treatment of HCC

  10. Experimental characterization of the water transport properties of PEM fuel cells diffusion media

    Science.gov (United States)

    Ramos-Alvarado, Bladimir; Sole, Joshua D.; Hernandez-Guerrero, Abel; Ellis, Michael W.

    2012-11-01

    A full experimental characterization of the liquid water transport properties of Toray TGP-090 paper is carried out in this work. Porosity, capillary pressure curves (capillary pressure-saturation relationships), absolute permeability, and relative permeability are obtained via experimental procedures. Porosity was determined using two methods, both aimed to obtain the solid volume of the network of fibers comprising the carbon paper. Capillary pressure curves were obtained using a gas displacement porosimeter where liquid water is injected using a syringe pump and the capillary pressure is recorded using a differential pressure transducer. Absolute and relative permeability were also measured with an apparatus designed at Virginia Tech. Absolute permeability was calculated at different flow rates using nitrogen. On the other hand, relative permeability was a more complicated task to carry out giving the complexity (two-phase flow condition) of this property. All of the water transport properties of Toray TGP-090 were studied under the effects of wet-proofing (PTFE treatment) and compression. Some observations were that wet-proofing reduces the porosity of the raw material, increases the hydrophobicity (Pc-S curves), and reduces the permeability of the material. Similar effects were observed for compression, where compressed material exhibited trends similar to those of wet-proofing effects. The results presented here will allow a more accurate modeling of PEMFCs, providing an experimentally verified alternative to the assumptions frequently employed.

  11. Numerical modeling of contaminant transport in fractured porous media using mixed finite-element and finitevolume methods

    KAUST Repository

    Dong, Chen

    2011-01-01

    A mathematical model for contaminant species passing through fractured porous media is presented. In the numerical model, we combine two locally conservative methods; i.e., the mixed finite-element (MFE) method and the finite-volume method. Adaptive triangle mesh is used for effective treatment of the fractures. A hybrid MFE method is employed to provide an accurate approximation of velocity fields for both the fractures and matrix, which are crucial to the convection part of the transport equation. The finite-volume method and the standard MFE method are used to approximate the convection and dispersion terms, respectively. The temporary evolution for the pressure distributions, streamline fields, and concentration profiles are obtained for six different arrangements of fractures. The results clearly show the distorted concentration effects caused by the ordered and disordered (random) patterns of the fractures and illustrate the robustness and efficiency of the proposed numerical model. © 2011 by Begell House Inc.

  12. Experimental study of contamination by a mixture resulting from the combustion of sodium in the presence of plutonium oxide

    International Nuclear Information System (INIS)

    Metivier, H.; Masse, R.; Nenot, J.C.; Nolibe, D.; Lafuma, J.

    1976-01-01

    The introduction into industry of breeder reactors using liquid sodium as the coolant gives rise to fresh radiotoxicological problems; the most likely chemical form in which the plutonium and sodium mixture may be found after a possible accident is a soluble oxide of plutonium(VI) or plutonium(VII). The biological behaviour of such mixtures was analysed in rats and monkeys following parenteral administration. In the case of rats distribution in the organs was analysed from 30 minutes to 30 days following intramuscular contamination. In the monkeys the authors only analysed distribution in the organs after one month. The biological behaviour of the mixture is marked by very high plutonium solubility. The maximum burden in the organs attains roughly 20% of the quantity deposited both in monkeys and rats. The spread of the plutonium proceeds gradually from the day of administration; it indicates that a soluble form of plutonium is present for a long time. Also observed is an increasing osteotropic tendency in the diffusible form. The liver fraction is rapidly removed, if it is assumed that faecal excretion represents biliary excretion. In the experimental conditions selected, the spread of a liquid aerosol of the solution is rapid and constitutes about 10% of the quantity deposited in the airways at the end of inhalation. Treatment with DTPA makes it possible to reduce the body burden, but less efficiently than after contamination by Pu(IV). (author)

  13. A computer code package for Monte Carlo photon-electron transport simulation Comparisons with experimental benchmarks

    International Nuclear Information System (INIS)

    Popescu, Lucretiu M.

    2000-01-01

    A computer code package (PTSIM) for particle transport Monte Carlo simulation was developed using object oriented techniques of design and programming. A flexible system for simulation of coupled photon, electron transport, facilitating development of efficient simulation applications, was obtained. For photons: Compton and photo-electric effects, pair production and Rayleigh interactions are simulated, while for electrons, a class II condensed history scheme was considered, in which catastrophic interactions (Moeller electron-electron interaction, bremsstrahlung, etc.) are treated in detail and all other interactions with reduced individual effect on electron history are grouped together using continuous slowing down approximation and energy straggling theories. Electron angular straggling is simulated using Moliere theory or a mixed model in which scatters at large angles are treated as distinct events. Comparisons with experimentally benchmarks for electron transmission and bremsstrahlung emissions energy and angular spectra, and for dose calculations are presented

  14. Inward particle transport at high collisionality in the Experimental Advanced Superconducting Tokamak

    International Nuclear Information System (INIS)

    Wang, G. Q.; Ma, J.; Weiland, J.; Zang, Q.

    2013-01-01

    We have made the first drift wave study of particle transport in the Experimental Advanced Superconducting Tokamak (Wan et al., Nucl. Fusion 49, 104011 (2009)). The results reveal that collisions make the particle flux more inward in the high collisionality regime. This can be traced back to effects that are quadratic in the collision frequency. The particle pinch is due to electron trapping which is not very efficient in the high collisionality regime so the approach to equilibrium is slow. We have included also the electron temperature gradient (ETG) mode to give the right electron temperature gradient, since the Trapped Electron Mode (TE mode) is weak in this regime. However, at the ETG mode number ions are Boltzmann distributed so the ETG mode does not give particle transport

  15. Experimental investigation of turbulent transport at the edge of a tokamak plasma

    International Nuclear Information System (INIS)

    Fedorczak, N.

    2010-01-01

    This manuscript is devoted to the experimental investigation of particle transport in the edge region of the tokamak Tore Supra. The first part introduces the motivations linked to energy production, the principle of a magnetic confinement and the elements of physics essential to describe the dynamic of the plasma at the edge region. From data collected by a set of Langmuir probes and a fast visible imaging camera, we demonstrate that the particle transport is dominated by the convection of plasma filaments, structures elongated along magnetic field lines. They present a finite wave number, responsible for the high enhancement of the particle flux at the low field side of the tokamak. This leads to the generation of strong parallel flows, and the strong constraint of filament geometry by the magnetic shear. (author)

  16. PAH contamination in soils adjacent to a coal-transporting facility in Tapin district, south Kalimantan, Indonesia.

    Science.gov (United States)

    Mizwar, Andy; Trihadiningrum, Yulinah

    2015-07-01

    This study was undertaken to determine the level of 16 polycyclic aromatic hydrocarbon (PAH), listed as priority pollutants by the United States Environmental Protection Agency (USEPA), in surface soils around a coal-transporting facility in the western part of South Kalimantan, Indonesia. Three composite soil samples were collected from a coal stockpile, coal-hauling road, and coal port. Identification and quantification of PAH was performed by gas chromatography-mass spectrometry. The total content of 16 USEPA-PAH ranged from 11.79 to 55.30 mg/kg with arithmetic mean value of 33.14 mg/kg and median of 32.33 mg/kg. The 16 USEPA-PAH measured levels were found to be greater compared with most of the literature values. The levels of high molecular-weight PAH (5- and 6-ring) were dominant and formed 67.77-80.69 % of the total 16 USEPA-PAH The most abundant of individual PAH are indeno[1,2,3-cd] pyrene and benzo[a]pyrene with concentration ranges of 2.11-20.56 and 1.59-17.84 mg/kg, respectively. The degree of PAH contamination and subsequent toxicity assessment suggest that the soils of the study area are highly contaminated and pose a potential health risk to humans.

  17. Transport of organic contaminants in subsoil horizons and effects of dissolved organic matter related to organic waste recycling practices.

    Science.gov (United States)

    Chabauty, Florian; Pot, Valérie; Bourdat-Deschamps, Marjolaine; Bernet, Nathalie; Labat, Christophe; Benoit, Pierre

    2016-04-01

    Compost amendment on agricultural soil is a current practice to compensate the loss of organic matter. As a consequence, dissolved organic carbon concentration in soil leachates can be increased and potentially modify the transport of other solutes. This study aims to characterize the processes controlling the mobility of dissolved organic matter (DOM) in deep soil layers and their potential impacts on the leaching of organic contaminants (pesticides and pharmaceutical compounds) potentially present in cultivated soils receiving organic waste composts. We sampled undisturbed soil cores in the illuviated horizon (60-90 cm depth) of an Albeluvisol. Percolation experiments were made in presence and absence of DOM with two different pesticides, isoproturon and epoxiconazole, and two pharmaceutical compounds, ibuprofen and sulfamethoxazole. Two types of DOM were extracted from two different soil surface horizons: one sampled in a plot receiving a co-compost of green wastes and sewage sludge applied once every 2 years since 1998 and one sampled in an unamended plot. Results show that DOM behaved as a highly reactive solute, which was continuously generated within the soil columns during flow and increased after flow interruption. DOM significantly increased the mobility of bromide and all pollutants, but the effects differed according the hydrophobic and the ionic character of the molecules. However, no clear effects of the origin of DOM on the mobility of the different contaminants were observed.

  18. An experimental study on the bio-surfactant-assisted remediation of crude oil and salt contaminated soils.

    Science.gov (United States)

    Zhang, Wen; Li, Jianbing; Huang, Guohe; Song, Weikun; Huang, Yuefei

    2011-01-01

    The effect of bio-surfactant (rhamnolipid) on the remediation of crude oil and salt contaminated soil was investigated in this study. The experimental results indicated that there was a distinct decline of total petroleum hydrocarbon (TPH) concentration within the soil when using rhamnolipid during a remediation period of 30 days, with maximum TPH reduction of 86.97%. The most effective remediation that was observed was with rhamnolipid at a concentration of 2 CMC in soil solution, and a first-order TPH degradation rate constant of 0.0866 d(-1). The results also illustrated that salts in soil had a negative impact on TPH reduction, and the degradation rate was negatively correlated with NaCl concentration in soil solution. The analysis of soil TPH fractions indicated that there was a significant reduction of C13-C30 during the remediation process when using bio-surfactant.

  19. A robotic system to conduct radiation and contamination surveys on nuclear waste transport casks

    International Nuclear Information System (INIS)

    Harrigan, R.W.; Sanders, T.L.

    1990-06-01

    The feasibility of performing, numerous spent fuel cask operations using fully integrated robotic systems is under evaluation. Using existing technology, operational and descriptive software and hardware in the form of robotic end effectors are being designed in conjunction with interfacing cask components. A robotic radiation and contamination survey system has been developed and used on mock-up cask hardware to evaluate the impact of such fully automated operations on cask design features and productivity. Based on experience gained from the survey system, numerous health physics operations can be reliably performed with little human intervention using a fully automated system. Such operations can also significantly reduce time requirements for cask-receiving operations. 7 refs., 51 figs., 6 tabs

  20. A comprehensive analysis of contaminant transport in the vadose zone beneath tank SX-109

    International Nuclear Information System (INIS)

    Ward, A.L.; Gee, G.W.; White, M.D.

    1997-02-01

    The Vadose Zone Characterization Project is currently investigating the subsurface distribution of gamma-emitting radionuclides in S and SX Waste Management Area (WMA-S-SX) located in the 200 West Area of the US Department of Energy's Hanford Site in southeastern Washington State. Spectral-gamma logging of boreholes has detected elevated 137 Cs concentrations as deep as 38 m, a depth considered excessive based on the assumed geochemistry of 137 Cs in Hanford sediments. Routine groundwater sampling under the Resource Conservation and Recovery Act (RCRA) have also detected elevated levels of site-specific contaminants downgradient of WMA-S-SX. The objective of this report is to explore the processes controlling the migration of 137 Cs, 99 Tc, and NO 3 through the vadose zone of WMA-S-SX, particularly beneath tank SX-109

  1. Contaminant transport modelling in tidal influenced water body for low level liquid waste discharge out

    International Nuclear Information System (INIS)

    Singh, Sanjay; Naidu, Velamala Simhadri

    2018-01-01

    Low level liquid waste is generated from nuclear reactor operation and reprocessing of spent fuel. This waste is discharged into the water body after removing bulk of its radioactivity. Dispersion of contaminant mainly depends on location of outfall and hydrodynamics of water body. For radiological impact assessment, in most of the analytical formulations, source term is taken as continuous release. However, this may not be always true as the water level is influenced by tidal movement and the selected outfall may come under intertidal zone in due course of the tidal cycle. To understand these phenomena, a case study has been carried out to evaluate hydrodynamic characteristics and dilution potential of outfall located in inter-tidal zone using numerical modelling

  2. A Novel Role of MerC in Methylmercury Transport and Phytoremediation of Methylmercury Contamination.

    Science.gov (United States)

    Sone, Yuka; Uraguchi, Shimpei; Takanezawa, Yasukazu; Nakamura, Ryosuke; Pan-Hou, Hidemitsu; Kiyono, Masako

    2017-01-01

    MerC, encoded by merC in the transposon Tn21 mer operon, is a heavy metal transporter with potential applications for phytoremediation of heavy metals such as mercuric ion and cadmium. In this study, we demonstrate that MerC also acts as a transporter for methylmercury. When MerC was expressed in Escherichia coli XL1-Blue, cells became hypersensitive to CH 3 Hg(I) and the uptake of CH 3 Hg(I) by these cells was higher than that by cells of the isogenic strain. Moreover, transgenic Arabidopsis plants expressing bacterial MerC or MerC fused to plant soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) accumulated CH 3 Hg(I) effectively and their growth was comparable to the wild-type plants. These results demonstrate that when the bacterium-derived merC gene is ectopically introduced in genetically modified plants, MerC expression in the transgenic plants promotes the transport and sequestration of methylmercury. Thus, our results show that the expression of merC in Arabidopsis results in transgenic plants that could be used for the phytoremediation and elimination of toxic methylmercury from the environment.

  3. Chemical disinfection of non-porous inanimate surfaces experimentally contaminated with four human pathogenic viruses.

    Science.gov (United States)

    Sattar, S A; Springthorpe, V S; Karim, Y; Loro, P

    1989-06-01

    The chemical disinfection of virus-contaminated non-porous inanimate surfaces was investigated using coxsackievirus B3, adenovirus type 5, parainfluenza virus type 3 and coronavirus 229E as representatives of important nosocomial viral pathogens. A 10 microliter amount of the test virus, suspended in either faeces or mucin, was placed onto each stainless steel disk (about 1 cm in diameter) and the inoculum allowed to dry for 1 h under ambient conditions. Sixteen disinfectant formulations were selected for this study based on the findings of an earlier investigation with a human rotavirus. After 1 min exposure to 20 microliters of the disinfectant, the virus from the disks was immediately eluted into tryptose phosphate broth and plaque assayed. Using an efficacy criterion of a 3 log10 or greater reduction in virus infectivity titre and irrespective of the virus suspending medium, only the following five disinfectants proved to be effective against all the four viruses tested: (1) 2% glutaraldehyde normally used as an instrument soak, (2) a strongly alkaline mixture of 0.5% sodium o-benzyl-p-chlorophenate and 0.6% sodium lauryl sulphate, generally used as a domestic disinfectant cleaner for hard surfaces, (3) a 0.04% solution of a quaternary ammonium compound containing 7% hydrochloric acid, which is the basis of many toilet bowl cleaners, (4) chloramine T at a minimum free chlorine level of 3000 p.p.m. and (5) sodium hypochlorite at a minimum free chlorine concentration of 5000 p.p.m. Of those chemicals suitable for use as topical antiseptics, 70% ethanol alone or products containing at least 70% ethanol were ineffective only against coxsackievirus B3. These results emphasize the care needed in selecting chemical disinfectants for routine use in infection control.

  4. Changes in population of S. enterica serotype Enteritidis in experimentally contaminated milk depending on temperature and acidity

    Directory of Open Access Journals (Sweden)

    Rajić-Savić Nataša

    2009-01-01

    Full Text Available Salmonella bacteria are among the most frequent causes of food poisoning, and milk and milk products are food items through which these bacteria can be transmitted. More recent data indicate that the infective dose of Salmonella is very small - up to 101/g/ml food. The preservation of Salmonella in milk depends on the acidity, temperature and the duration of storage. The objective of the work was to examine the survival of Salmonella in milk depending on the changes of the total number of bacteria, pH and temperature. In the study, 0.1 ml of 24-hour bouillon culture of S. enteritidis was inoculated in raw collective milk (104 cfu/ml and in marketed pasteurized milk (102 cfu/ml each. The examined milk samples were maintained at room temperature and at a temperature of 7oC. At the beginning of the examinations, after 24h, 48h, 72h, after 7, 14 and 21 days, decimal solutions were made from the milk, and, following incubation, the number of S. enteritidis was determined (Rambach agar, the total number of bacteria (base for total number of bacteria by multiplying the number of grown colonies and the corresponding solution, and the milk pH was measured. There was a bigger reduction of S. enteritidis at room temperature because the pH value dropped more swiftly. The lowest pH at which S. enteritidis was isolated from experimentally contaminated milk was 3.88. The results of the examinations show that Salmonella can adapt to biochemical processes during milk acid fermentation of soft cheeses. No Salmonella bacteria were isolated from experimentally contaminated pasterurized milk at both maintenance temperatures after seven days of investigations.

  5. Code-To-Code Benchmarking Of The Porflow And GoldSim Contaminant Transport Models Using A Simple 1-D Domain - 11191

    International Nuclear Information System (INIS)

    Hiergesell, R.; Taylor, G.

    2010-01-01

    An investigation was conducted to compare and evaluate contaminant transport results of two model codes, GoldSim and Porflow, using a simple 1-D string of elements in each code. Model domains were constructed to be identical with respect to cell numbers and dimensions, matrix material, flow boundary and saturation conditions. One of the codes, GoldSim, does not simulate advective movement of water; therefore the water flux term was specified as a boundary condition. In the other code, Porflow, a steady-state flow field was computed and contaminant transport was simulated within that flow-field. The comparisons were made solely in terms of the ability of each code to perform contaminant transport. The purpose of the investigation was to establish a basis for, and to validate follow-on work that was conducted in which a 1-D GoldSim model developed by abstracting information from Porflow 2-D and 3-D unsaturated and saturated zone models and then benchmarked to produce equivalent contaminant transport results. A handful of contaminants were selected for the code-to-code comparison simulations, including a non-sorbing tracer and several long- and short-lived radionuclides exhibiting both non-sorbing to strongly-sorbing characteristics with respect to the matrix material, including several requiring the simulation of in-growth of daughter radionuclides. The same diffusion and partitioning coefficients associated with each contaminant and the half-lives associated with each radionuclide were incorporated into each model. A string of 10-elements, having identical spatial dimensions and properties, were constructed within each code. GoldSim's basic contaminant transport elements, Mixing cells, were utilized in this construction. Sand was established as the matrix material and was assigned identical properties (e.g. bulk density, porosity, saturated hydraulic conductivity) in both codes. Boundary conditions applied included an influx of water at the rate of 40 cm/yr at one

  6. Contaminant transport in fracture networks with heterogeneous rock matrices. The Picnic code

    International Nuclear Information System (INIS)

    Barten, Werner; Robinson, Peter C.

    2001-02-01

    In the context of safety assessment of radioactive waste repositories, complex radionuclide transport models covering key safety-relevant processes play a major role. In recent Swiss safety assessments, such as Kristallin-I, an important drawback was the limitation in geosphere modelling capability to account for geosphere heterogeneities. In marked contrast to this limitation in modelling capabilities, great effort has been put into investigating the heterogeneity of the geosphere as it impacts on hydrology. Structural geological methods have been used to look at the geometry of the flow paths on a small scale and the diffusion and sorption properties of different rock materials have been investigated. This huge amount of information could however be only partially applied in geosphere transport modelling. To make use of these investigations the 'PICNIC project' was established as a joint cooperation of PSI/Nagra and QuantiSci to provide a new geosphere transport model for Swiss safety assessment of radioactive waste repositories. The new transport code, PICNIC, can treat all processes considered in the older geosphere model RANCH MD generally used in the Kristallin-I study and, in addition, explicitly accounts for the heterogeneity of the geosphere on different spatial scales. The effects and transport phenomena that can be accounted for by PICNIC are a combination of (advective) macro-dispersion due to transport in a network of conduits (legs), micro-dispersion in single legs, one-dimensional or two-dimensional matrix diffusion into a wide range of homogeneous and heterogeneous rock matrix geometries, linear sorption of nuclides in the flow path and the rock matrix and radioactive decay and ingrowth in the case of nuclide chains. Analytical and numerical Laplace transformation methods are integrated in a newly developed hierarchical linear response concept to efficiently account for the transport mechanisms considered which typically act on extremely different

  7. Contaminant transport in fracture networks with heterogeneous rock matrices. The Picnic code

    Energy Technology Data Exchange (ETDEWEB)

    Barten, Werner [Paul Scherrer Inst., CH-5232 Villigen PSI (Switzerland); Robinson, Peter C. [QuantiSci Limited, Henley-on-Thames (United Kingdom)

    2001-02-01

    In the context of safety assessment of radioactive waste repositories, complex radionuclide transport models covering key safety-relevant processes play a major role. In recent Swiss safety assessments, such as Kristallin-I, an important drawback was the limitation in geosphere modelling capability to account for geosphere heterogeneities. In marked contrast to this limitation in modelling capabilities, great effort has been put into investigating the heterogeneity of the geosphere as it impacts on hydrology. Structural geological methods have been used to look at the geometry of the flow paths on a small scale and the diffusion and sorption properties of different rock materials have been investigated. This huge amount of information could however be only partially applied in geosphere transport modelling. To make use of these investigations the 'PICNIC project' was established as a joint cooperation of PSI/Nagra and QuantiSci to provide a new geosphere transport model for Swiss safety assessment of radioactive waste repositories. The new transport code, PICNIC, can treat all processes considered in the older geosphere model RANCH MD generally used in the Kristallin-I study and, in addition, explicitly accounts for the heterogeneity of the geosphere on different spatial scales. The effects and transport phenomena that can be accounted for by PICNIC are a combination of (advective) macro-dispersion due to transport in a network of conduits (legs), micro-dispersion in single legs, one-dimensional or two-dimensional matrix diffusion into a wide range of homogeneous and heterogeneous rock matrix geometries, linear sorption of nuclides in the flow path and the rock matrix and radioactive decay and ingrowth in the case of nuclide chains. Analytical and numerical Laplace transformation methods are integrated in a newly developed hierarchical linear response concept to efficiently account for the transport mechanisms considered which typically act on extremely

  8. Experimental methods and transport models for drug delivery across the blood-brain barrier.

    Science.gov (United States)

    Fu, Bingmei M

    2012-06-01

    The blood-brain barrier (BBB) is a dynamic barrier essential for maintaining the micro-environment of the brain. Although the special anatomical features of the BBB determine its protective role for the central nervous system (CNS) from blood-born neurotoxins, however, the BBB extremely limits the therapeutic efficacy of drugs into the CNS, which greatly hinders the treatment of major brain diseases. This review summarized the unique structures of the BBB, described a variety of in vivo and in vitro experimental methods for determining the transport properties of the BBB, e.g., the permeability of the BBB to water, ions, and solutes including nutrients, therapeutic agents and drug carriers, and presented newly developed mathematical models which quantitatively correlate the anatomical structures of the BBB with its barrier functions. Finally, on the basis of the experimental observations and the quantitative models, several strategies for drug delivery through the BBB were proposed.

  9. Recent experimental studies of edge and internal transport barriers in the DIII-D tokamak

    International Nuclear Information System (INIS)

    Gohil, P; Baylor, L R; Burrell, K H; Casper, T A; Doyle, E J; Greenfield, C M; Jernigan, T C; Kinsey, J E; Lasnier, C J; Moyer, R A; Murakami, M; Rhodes, T L; Rudakov, D L; Staebler, G M; Wang, G; Watkins, J G; West, W P; Zeng, L

    2003-01-01

    Results from recent experiments on the DIII-D tokamak have revealed many important details on transport barriers at the plasma edge and in the plasma core. These experiments include: (a) the formation of the H-mode edge barrier directly by pellet injection; (b) the formation of a quiescent H-mode edge barrier (QH-mode) which is free from edge localized modes, but which still exhibits good density and radiative power control; (c) the formation of multiple transport barriers, such as the quiescent double barrier (QDB) which combines an internal transport barrier with the quiescent H-mode edge barrier. Results from the pellet-induced H-mode experiments indicate that: (a) the edge temperature (electron or ion) does not need to attain a critical value for the formation of the H-mode barrier, (b) pellet injection leads to an increased gradient in the radial electric field, E r , at the plasma edge; (c) the experimentally determined edge parameters at barrier transition are well below the predictions of several theories on the formation of the H-mode barrier, (d) pellet injection can lower the threshold power required to form the H-mode barrier. The quiescent H-mode barrier exhibits good density control as the result of continuous magnetohydrodynamic activity at the plasma edge called the edge harmonic oscillation (EHO). The EHO enhances the edge particle transport whilst maintaining a good energy transport barrier. The ability to produce multiple barriers in the QDB regime has led to long duration, high-performance plasmas with β N H 89 values of 7 for up to 10 times the confinement time. Density profile control in the plasma core of QDB plasmas has been demonstrated using on-axis electron cyclotron heating

  10. Review: Selenium contamination, fate, and reactive transport in groundwater in relation to human health

    Science.gov (United States)

    Bailey, Ryan T.

    2017-06-01

    Selenium (Se) is an essential micro-nutrient for humans, but can be toxic at high levels of intake. Se deficiency and Se toxicity are linked with serious diseases, with some regions worldwide experiencing Se deficiency due to Se-poor rocks and soils and other areas dealing with Se toxicity due to the presence of Se-enriched geologic materials. In addition, Se is consumed primarily through plants that take up Se from soil and through animal products that consume these plants. Hence, the soil and groundwater system play important roles in determining the effect of Se on human health. This paper reviews current understanding of Se fate and transport in soil and groundwater systems and its relation to human health, with a focus on alluvial systems, soil systems, and the interface between alluvial systems and Cretaceous shale that release Se via oxidation processes. The review focuses first on the relation between Se and human health, followed by a summary of Se distribution in soil-aquifer systems, with an emphasis on the quantitative relationship between Se content in soil and Se concentration in underlying groundwater. The physical, chemical, and microbial processes that govern Se fate and transport in subsurface systems then are presented, followed by numerical modeling techniques used to simulate these processes in study regions and available remediation strategies for either Se-deficient or Se-toxic regions. This paper can serve as a guide to any field, laboratory or modeling study aimed at assessing Se fate and transport in groundwater systems and its relation to human health.

  11. Modeling contaminant transport in porous media in relation to nuclear-waste disposal: a review

    International Nuclear Information System (INIS)

    Grove, D.B.; Kipp, K.L.

    1980-01-01

    The modeling of solute transport in saturated porous media is reviewed as it is applied to the movement of radioactive waste in the subsurface. Those processes, both physical and chemical, that affect radionuclide movement are discussed and the references that best illustrate these processes listed. Movement is separated into convection, convection-dispersion, and convection-dispersion and chemical reactions. Solutions of equations describing such movement are divided into one-, two-, and three-dimensional analytical and numerical examples. Discussions of recent work in the area of stochastic modeling are followed by discussions of applications of the models to selected field sites

  12. The Oak Ridge Field Research Center : Advancing Scientific Understanding of the Transportation, Fate, and Remediation of Subsurface Contamination Sources and Plumes

    International Nuclear Information System (INIS)

    David Watson

    2005-01-01

    Historical research, development, and testing of nuclear materials across this country resulted in subsurface contamination that has been identified at over 7,000 discrete sites across the U.S. Department of Energy (DOE) complex. With the end of the Cold War threat, DOE has shifted its emphasis to remediation, decommissioning, and decontamination of the immense volumes of contaminated groundwater, sediments, and structures at its sites. DOE currently is responsible for remediating 1.7 trillion gallons of contaminated groundwater, an amount equal to approximately four times the daily U.S. water consumption, and 40 million cubic meters of contaminated soil, enough to fill approximately 17 professional sports stadiums.* DOE also sponsors research intended to improve or develop remediation technologies, especially for difficult, currently intractable contaminants or conditions. The Oak Ridge FRC is representative of some difficult sites, contaminants, and conditions. Buried wastes in contact with a shallow water table have created huge reservoirs of contamination. Rainfall patterns affect the water table level seasonally and over time. Further, the hydrogeology of the area, with its fractures and karst geology, affects the movement of contaminant plumes. Plumes have migrated long distances and to surface discharge points through ill-defined preferred flowpaths created by the fractures and karst conditions. From the standpoint of technical effectiveness, remediation options are limited, especially for contaminated groundwater. Moreover, current remediation practices for the source areas, such as capping, can affect coupled processes that, in turn, may affect the movement of subsurface contaminants in unknown ways. Research conducted at the FRC or with FRC samples therefore promotes understanding of the processes that influence the transport and fate of subsurface contaminants, the effectiveness and long-term consequences of extant remediation options, and the

  13. Contaminant transport in fractured porous media: analytical solution for a two-member decay chain in a single fracture

    International Nuclear Information System (INIS)

    Sudicky, E.A.; Frind, E.O.

    1984-01-01

    An analytical solution is presented for the problem of radionuclide chain decay during transport through a discrete fracture situated in a porous rock matrix. The solution takes into account advection along the fracture, molecular diffusion from the fracture to the porous matrix, adsorption on the fracture face, adsorption in the rock matrix, and radioactive decay. The solution for the daughter product is in the form of a double integral which is evaluated by Gauss-Legendre quadrature. Results show that the daughter product tends to advance ahead of the parent nuclide even when the half-life of the parent is larger. This is attributed to the effect of chain decay in the matrix, which tends to reduce the diffusive loss of the daughter along the fracture. The examples also demonstrate that neglecting the parent nuclide and modeling its daughter as a single species can result in significant overestimation of arrival times at some point along the fracture. Although the analytical solution is restricted to a two-member chain for practical reasons, it represents a more realistic description of nuclide transport along a fracture than available single-species models. The solution may be of use for application to other contaminants undergoing different types of first-order transformation reactions

  14. Solutal Marangoni flows of miscible liquids drive transport without surface contamination

    Science.gov (United States)

    Kim, Hyoungsoo; Muller, Koen; Shardt, Orest; Afkhami, Shahriar; Stone, Howard A.

    2017-11-01

    Mixing and spreading of different liquids are omnipresent in nature, life and technology, such as oil pollution on the sea, estuaries, food processing, cosmetic and beverage industries, lab-on-a-chip devices, and polymer processing. However, the mixing and spreading mechanisms for miscible liquids remain poorly characterized. Here, we show that a fully soluble liquid drop deposited on a liquid surface remains as a static lens without immediately spreading and mixing, and simultaneously a Marangoni-driven convective flow is generated, which are counterintuitive results when two liquids have different surface tensions. To understand the dynamics, we develop a theoretical model to predict the finite spreading time and length scales, the Marangoni-driven convection flow speed, and the finite timescale to establish the quasi-steady state for the Marangoni flow. The fundamental understanding of this solutal Marangoni flow may enable driving bulk flows and constructing an effective drug delivery and surface cleaning approach without causing surface contamination by immiscible chemical species.

  15. Stochastic estimation and simulation of heterogeneities important for transport of contaminants in the unsaturated zone

    Energy Technology Data Exchange (ETDEWEB)

    Kitteroed, Nils-Otto

    1997-12-31

    The background for this thesis was the increasing risk of contamination of water resources and the requirement of groundwater protection. Specifically, the thesis implements procedures to estimate and simulate observed heterogeneities in the unsaturated zone and evaluates what impact the heterogeneities may have on the water flow. The broad goal was to establish a reference model with high spatial resolution within a small area and to condition the model using spatially frequent field observations, and the Moreppen site at Oslo`s new major airport was used for this purpose. An approach is presented for the use of ground penetrating radar in which indicator kriging is used to estimate continuous stratigraphical architecture. Kriging is also used to obtain 3D images of soil moisture. A simulation algorithm based on the Karhunen-Loeve expansion is evaluated and a modification of the Karhunen-Loeve simulation is suggested that makes it possible to increase the size of the simulation lattice. This is obtained by kriging interpolation of the eigenfunctions. 250 refs., 40 figs., 7 tabs.

  16. EXPERIMENTAL COMPARISON OF THE AEROSOL METHOD OF DISINFECTION OF AIR AND SURFACES CONTAMINATED BY M. TUBERCULOSIS

    Directory of Open Access Journals (Sweden)

    V. V. Kuzin

    2018-01-01

    instead of disinfectant for control tests treating the tests objects contaminated in the same manner.Results. The good disinfection properties of Green Dez aerosol were proved during the simulation of M. tuberculosis, H37Rv strain, disinfection on the surfaces and in the air.The efficiency analysis of the aerosol method of disinfection proved the reduction of disinfectant consumption by 4-5 times versus wiping and irrigation, due to this the aerosol treatment can be regarded as a safer and more environmentally friendly method.The finely dispersed disinfectant aerosol, produced by MNC, effectively decontaminated the whole space, including the remote and hard-to-reach places. Full automation of disinfection implies no human presence providing high safety of disinfection. 

  17. Experimental models in the rat for the assessment of local and systemic behaviour and decorporation of MOX after contamination by wounding

    International Nuclear Information System (INIS)

    Griffiths, N.M.; Van der Meeren, A.; Abram, M.C.; Chau, Q.; Coudert, S.; Renault, D.; Wilk, J.C.; Guichet, C.; Helfer, N.; Angulo-Mora, J.

    2013-11-01

    Accidental contamination of nuclear industry workers by alpha particle-emitting actinides (plutonium; Pu, americium; Am) can occur after wounding. Transfer from the wound depends on contaminant physicochemical properties, wound type and anatomical location. These factors and wound activity levels direct the ensuing medical approaches. The principal objective of this research program, carried out in the Laboratoire de Radio-Toxicologie (CEA/DSV) in collaboration with AREVA NC, was to establish models of actinide-contaminated wounds in the rat using multidisciplinary approaches. Rats were contaminated by MOX (7.1% Pu by mass) or Pu nitrate or Am nitrate, either by subcutaneous implantation of an agarose gel containing the radioelement or following incision of the hind limb muscles. Actinide urinary excretion, wound, tissue levels and effects of decorporant regimens including wound excision were evaluated. In both experimental models following MOX contamination, urinary Am excretion was greater than Pu, and bone Pu and Am retention increased significantly with time. Moreover after Pu or Am nitrate contamination, Am excretion and tissue retention was greater than Pu again reflecting the higher solubility of Am. Coherent with the insoluble nature of oxide forms, tissue Am or Pu levels were much lower after MOX compared to those seen after nitrates. Wound site actinide retention was also much higher after MOX contamination. Repeated systemic DTPA increased actinide urinary excretion and decreased tissue retention, as did single or repeated local DTPA. Pu urinary excretion was transiently increased after wound excision but no further Pu organ retention was observed. In conclusion, several different experimental models have been developed in the rat to simulate actinide wound contamination. Information obtained on Pu and Am behavior either at the wound site or at distant organs allowed the discrimination between different physicochemical actinide forms and evaluation of

  18. Theoretical modeling and experimental validation of transport and separation properties of carbon nanotube electrospun membrane distillation

    KAUST Repository

    Lee, Jung Gil; Lee, Eui-Jong; Jeong, Sanghyun; Guo, Jiaxin; An, Alicia Kyoungjin; Guo, Hong; Kim, Joonha; Leiknes, TorOve; Ghaffour, NorEddine

    2016-01-01

    Developing a high flux and selective membrane is required to make membrane distillation (MD) a more attractive desalination process. Amongst other characteristics membrane hydrophobicity is significantly important to get high vapor transport and low wettability. In this study, a laboratory fabricated carbon nanotubes (CNTs) composite electrospun (E-CNT) membrane was tested and has showed a higher permeate flux compared to poly(vinylidene fluoride-co-hexafluoropropylene) (PH) electrospun membrane (E-PH membrane) in a direct contact MD (DCMD) configuration. Only 1% and 2% of CNTs incorporation resulted in an enhanced permeate flux with lower sensitivity to feed salinity while treating a 35 and 70 g/L NaCl solutions. Experimental results and the mechanisms of E-CNT membrane were validated by a proposed new step-modeling approach. The increased vapor transport in E-CNT membranes could not be elucidated by an enhancement of mass transfer only at a given physico-chemical properties. However, the theoretical modeling approach considering the heat and mass transfers simultaneously enabled to explain successfully the enhanced flux in the DCMD process using E-CNT membranes. This indicates that both mass and heat transfers improved by CNTs are attributed to the enhanced vapor transport in the E-CNT membrane.

  19. Theoretical modeling and experimental validation of transport and separation properties of carbon nanotube electrospun membrane distillation

    KAUST Repository

    Lee, Jung Gil

    2016-12-27

    Developing a high flux and selective membrane is required to make membrane distillation (MD) a more attractive desalination process. Amongst other characteristics membrane hydrophobicity is significantly important to get high vapor transport and low wettability. In this study, a laboratory fabricated carbon nanotubes (CNTs) composite electrospun (E-CNT) membrane was tested and has showed a higher permeate flux compared to poly(vinylidene fluoride-co-hexafluoropropylene) (PH) electrospun membrane (E-PH membrane) in a direct contact MD (DCMD) configuration. Only 1% and 2% of CNTs incorporation resulted in an enhanced permeate flux with lower sensitivity to feed salinity while treating a 35 and 70 g/L NaCl solutions. Experimental results and the mechanisms of E-CNT membrane were validated by a proposed new step-modeling approach. The increased vapor transport in E-CNT membranes could not be elucidated by an enhancement of mass transfer only at a given physico-chemical properties. However, the theoretical modeling approach considering the heat and mass transfers simultaneously enabled to explain successfully the enhanced flux in the DCMD process using E-CNT membranes. This indicates that both mass and heat transfers improved by CNTs are attributed to the enhanced vapor transport in the E-CNT membrane.

  20. Phytovolatilization of Organic Contaminants.

    Science.gov (United States)

    Limmer, Matt; Burken, Joel

    2016-07-05

    Plants can interact with a variety of organic compounds, and thereby affect the fate and transport of many environmental contaminants. Volatile organic compounds may be volatilized from stems or leaves (direct phytovolatilization) or from soil due to plant root activities (indirect phytovolatilization). Fluxes of contaminants volatilizing from plants are important across scales ranging from local contaminant spills to global fluxes of methane emanating from ecosystems biochemically reducing organic carbon. In this article past studies are reviewed to clearly differentiate between direct- and indirect-phytovolatilization and we discuss the plant physiology driving phytovolatilization in different ecosystems. Current measurement techniques are also described, including common difficulties in experimental design. We also discuss reports of phytovolatilization in the literature, finding that compounds with low octanol-air partitioning coefficients are more likely to be phytovolatilized (log KOA < 5). Reports of direct phytovolatilization at field sites compare favorably to model predictions. Finally, future research needs are presented that could better quantify phytovolatilization fluxes at field scale.

  1. H51E-1535: Biogeochemical factors influencing the transport and fate of colloids and colloid-associated contaminants in the vadose zone

    Science.gov (United States)

    The vadose zone exhibits large spatial and temporal variability in many physical, chemical, and biological factors that strongly influence the transport and fate of colloids (e.g., microbes, nanoparticles, clays, and dissolved organic matter) and colloid-associated contaminants (e.g., heavy metals, ...

  2. Risk assessment through drinking water pathway via uncertainty modeling of contaminant transport using soft computing

    International Nuclear Information System (INIS)

    Datta, D.; Ranade, A.K.; Pandey, M.; Sathyabama, N.; Kumar, Brij

    2012-01-01

    The basic objective of an environmental impact assessment (EIA) is to build guidelines to reduce the associated risk or mitigate the consequences of the reactor accident at its source to prevent deterministic health effects, to reduce the risk of stochastic health effects (eg. cancer and severe hereditary effects) as much as reasonable achievable by implementing protective actions in accordance with IAEA guidance (IAEA Safety Series No. 115, 1996). The measure of exposure being the basic tool to take any appropriate decisions related to risk reduction, EIA is traditionally expressed in terms of radiation exposure to the member of the public. However, models used to estimate the exposure received by the member of the public are governed by parameters some of which are deterministic with relative uncertainty and some of which are stochastic as well as imprecise (insufficient knowledge). In an admixture environment of this type, it is essential to assess the uncertainty of a model to estimate the bounds of the exposure to the public to invoke a decision during an event of nuclear or radiological emergency. With a view to this soft computing technique such as evidence theory based assessment of model parameters is addressed to compute the risk or exposure to the member of the public. The possible pathway of exposure to the member of the public in the aquatic food stream is the drinking of water. Accordingly, this paper presents the uncertainty analysis of exposure via uncertainty analysis of the contaminated water. Evidence theory finally addresses the uncertainty in terms of lower bound as belief measure and upper bound of exposure as plausibility measure. In this work EIA is presented using evidence theory. Data fusion technique is used to aggregate the knowledge on the uncertain information. Uncertainty of concentration and exposure is expressed as an interval of belief, plausibility

  3. Effects of acute and chronic experimental contamination on direct cesium 137 uptake by the eel, Anguilla anguilla L

    International Nuclear Information System (INIS)

    Foulquier, Luc; Lambrechts, Alain.

    1982-03-01

    This study covers the effects of different types of contamination on direct cesium 137 uptake by the eel. In the first experiment (acute contamination), simulating a waste discharge, the fish were kept in water with a rapidly decreasing cesium 137 activity. In a second experiment (chronic contamination), the water activity increased constantly, simulating increasing waste frequency and activity levels. Irrespective of the type of contamination, radiocesium retention by eels is low ( [fr

  4. Estimating fate and transport of multiple contaminants in the vadose zone using a multi-layered soil column and three-phase equilibrium partitioning model

    International Nuclear Information System (INIS)

    Rucker, Gregory G.

    2007-01-01

    Soils at waste sites must be evaluated for the potential of residual soil contamination to leach and migrate to the groundwater beneath the disposal area. If migration to the aquifer occurs, contaminants can travel vast distances and pollute drinking water wells, thus exposing human receptors to harmful levels of toxins and carcinogens. To prevent groundwater contamination, a contaminant fate and transport analysis is necessary to assess the migration potential of residual soil contaminants. This type of migration analysis is usually performed using a vadose zone model to account for complex geotechnical and chemical variables including: decay processes, infiltration rate, soil properties, vadose zone thickness, and chemical behavior. The distinct advantage of using a complex model is that less restrictive, but still protective, soil threshold levels may be determined avoiding the unnecessary and costly remediation of marginally contaminated soils. However, the disadvantage of such modeling is the additional cost for data collection and labor required to apply these models. In order to allay these higher costs and to achieve a less restrictive but still protective clean-up level, a multiple contaminant and multi layered soil column equilibrium partitioning model was developed which is faster, simpler and less expensive to use. (authors)

  5. Uptake and transport of radioactive cesium and strontium into grapevines after leaf contamination

    Science.gov (United States)

    Zehnder, H. J.; Kopp, P.; Eikenberg, J.; Feller, U.; Oertli, J. J.

    1995-07-01

    From 1989 to 1993 the foliar uptake of radioactive strontium (Sr-85) and cesium (Cs-134) by selected leaves of grapevine plants and the subsequent redistribution within the plants was examined under controlled conditions in a greenhouse. The radionuclides were applied as chlorides. These plants were grown in large pots containing a mixture of local soil and peat. Plant and soil samples were analyzed throughout the growing season and also during the following vegetation period. Only traces of the applied radiostrontium were taken up by the leaves. This element was essentially not redistributed within the plants. In contrast, radiocesium was easily taken up through the leaf surface, transported to other plant parts and to some extent released from the roots into the soil. Cesium reaching the soil may interact with clay particles causing a very reduced availability for plants. Therefore the soil may act as a long-term sink for radiocesium. On the other hand, grape berries represent transient sinks. The cesium levels in the berries decreased again in a late phase of maturation, but the mechanisms causing this loss are not yet identified. During the second vegetation period, only a very minor proportion of the radiocesium taken up previously by the plants was present in the above ground parts.

  6. Modeling Water Exchange and Contaminant Transport through a Baltic Coastal Region

    International Nuclear Information System (INIS)

    Engqvist, Anders; Doeoes, Kristofer; Andrejev, Oleg

    2006-01-01

    The water exchange of the Baltic coastal zone is characterized by its seasonally varying regimes. In the safety assessment of a potential repository for spent nuclear fuel, it is important to assess the consequences of a hypothetical leak of radionuclides through the seabed into a waterborne transport phase. In particular, estimates of the associated residence times in the near-shore coastal zone are of interest. There are several methods to quantify such measures, of which three are presented here. Using the coastal location of Forsmark (Sweden) as an example, methods based on passive tracers, particle trajectories, and the average age distribution of exogenous water parcels are compared for a representative one-year cycle. Tracer-based methods can simulate diffusivity more realistically than the other methods. Trajectory-based methods can handle Lagrangian dispersion processes due to advection but neglect diffusion on the sub-grid scale. The method based on the concept of average age (AvA) of exogenous water can include all such sources simultaneously not only boundary water bodies but also various (fresh)water discharges. Due to the inclusion of sub-grid diffusion this method gives a smoother measure of the water renewal. It is shown that backward in time trajectories and AvA-times are basically equipollent methods, yielding correlated results within the limits set by the diffusivity

  7. Retinal glutamate transporter changes in experimental glaucoma and after optic nerve transection in the rat.

    Science.gov (United States)

    Martin, Keith R G; Levkovitch-Verbin, Hana; Valenta, Danielle; Baumrind, Lisa; Pease, Mary Ellen; Quigley, Harry A

    2002-07-01

    High levels of glutamate can be toxic to retinal ganglion cells. Effective buffering of extracellular glutamate by retinal glutamate transporters is therefore important. This study was conducted to investigate whether glutamate transporter changes occur with two models of optic nerve injury in the rat. Glaucoma was induced in one eye of 35 adult Wistar rats by translimbal diode laser treatment to the trabecular meshwork. Twenty-five more rats underwent unilateral optic nerve transection. Two glutamate transporters, GLAST (EAAT-1) and GLT-1 (EAAT-2), were studied by immunohistochemistry and quantitative Western blot analysis. Treated and control eyes were compared 3 days and 1, 4, and 6 weeks after injury. Optic nerve damage was assessed semiquantitatively in epoxy-embedded optic nerve cross sections. Trabecular laser treatment resulted in moderate intraocular pressure (IOP) elevation in all animals. After 1 to 6 weeks of experimental glaucoma, all treated eyes had significant optic nerve damage. Glutamate transporter changes were not detected by immunohistochemistry. Western blot analysis demonstrated significantly reduced GLT-1 in glaucomatous eyes compared with control eyes at 3 days (29.3% +/- 6.7%, P = 0.01), 1 week (55.5% +/- 13.6%, P = 0.02), 4 weeks (27.2% +/- 10.1%, P = 0.05), and 6 weeks (38.1% +/- 7.9%, P = 0.01; mean reduction +/- SEM, paired t-tests, n = 5 animals per group, four duplicate Western blot analyses per eye). The magnitude of the reduction in GLT-1 correlated significantly with mean IOP in the glaucomatous eye (r(2) = 0.31, P = 0.01, linear regression). GLAST was significantly reduced (33.8% +/- 8.1%, mean +/- SEM) after 4 weeks of elevated IOP (P = 0.01, paired t-test, n = 5 animals per group). In contrast to glaucoma, optic nerve transection resulted in an increase in GLT-1 compared with the control eye (P = 0.01, paired t-test, n = 15 animals). There was no significant change in GLAST after transection. GLT-1 and GLAST were significantly

  8. Numerical and experimental approaches to study soil transport and clogging in granular filters

    Science.gov (United States)

    Kanarska, Y.; Smith, J. J.; Ezzedine, S. M.; Lomov, I.; Glascoe, L. G.

    2012-12-01

    Failure of a dam by erosion ranks among the most serious accidents in civil engineering. The best way to prevent internal erosion is using adequate granular filters in the transition areas where important hydraulic gradients can appear. In case of cracking and erosion, if the filter is capable of retaining the eroded particles, the crack will seal and the dam safety will be ensured. Numerical modeling has proved to be a cost-effective tool for improving our understanding of physical processes. Traditionally, the consideration of flow and particle transport in porous media has focused on treating the media as continuum. Practical models typically address flow and transport based on the Darcy's law as a function of a pressure gradient and a medium-dependent permeability parameter. Additional macroscopic constitutes describe porosity, and permeability changes during the migration of a suspension through porous media. However, most of them rely on empirical correlations, which often need to be recalibrated for each application. Grain-scale modeling can be used to gain insight into scale dependence of continuum macroscale parameters. A finite element numerical solution of the Navier-Stokes equations for fluid flow together with Lagrange multiplier technique for solid particles was applied to the simulation of soil filtration in the filter layers of gravity dam. The numerical approach was validated through comparison of numerical simulations with the experimental results of base soil particle clogging in the filter layers performed at ERDC. The numerical simulation correctly predicted flow and pressure decay due to particle clogging. The base soil particle distribution was almost identical to those measured in the laboratory experiment. It is believed that the agreement between simulations and experimental data demonstrates the applicability of the proposed approach for prediction of the soil transport and clogging in embankment dams. To get more precise understanding of

  9. Activity of alkaline phosphatase and its fractions in blood serum of rats with experimental hyperthyroidism, kept in a radionuclide contaminated area

    International Nuclear Information System (INIS)

    Markova, A.G.; Bagel', I.M.

    2002-01-01

    In studies on male rats, with experimentally induced thyrotoxicosis a modifying effect of the stay in radioactively contaminated zone on the total alkaline phosphatase activity was shown. The data indicate disturbances in calcium-phosphoric metabolism, resulting in pronounced deviations from the normal range in the activity of thermolabile (bone) fraction (authors)

  10. Influence of Roughness-Induced Slip on Colloid Transport: Experimental and Modelling Insights

    Science.gov (United States)

    Rasmuson, J. A.; Johnson, W. P.

    2017-12-01

    A limitation of classic colloid filtration theory is that it applies only to smooth surfaces, yet most natural surfaces present some degree of nano- to micro-scale roughness. A large volume of research has been dedicated to understanding the effects of roughness on particle attachment at the nano-scale since these interactions dictate field scale transport behavior. It has been previously demonstrated that roughness imposes a finite slip vector at the surface that causes particles to experience higher near-surface velocities than would be expected over a smooth surface. Slip near a rough surface can affect two primary mechanisms of particle attenuation: 1) interception of the surface (finding a landing spot) and 2) arrest on the surface (sticking the landing). However, a clear designation on how slip affects particle transport near rough surfaces is missing. The goal of this study was to provide a guide for the height of the slip layer and contact surface in reference to the mean-plane for rough surfaces. Direct observation was used to measure near-surface velocities of particles translating near surfaces of varying roughness spanning three orders of magnitude. The influence of roughness on particle transport was investigated using computational fluid dynamics (CFD) modeling with rough surfaces measured with atomic force microscopy (AFM). The CFD and experimental results were used to calibrate a Lagrangian particle transport model that utilizes simple modifications to the flow field for a smooth surface using statistically based roughness parameters. Advantages of the Lagrangian model are significantly decreased computation times and applicability to a wide range of natural surfaces without explicitly simulating individual asperities. The results suggest that the no-slip boundary should be placed at the bottom of the maximum asperity valleys, and that the contact surface should be placed at the root mean square (RMS) roughness above the mean plane. Collector

  11. Natural organics in groundwaters and their potential effect on contaminant transport in granitic rock

    International Nuclear Information System (INIS)

    Vilks, P.; Bachinski, D.B.; Richer, D.

    1996-07-01

    Naturally occurring organics in groundwaters of the Whiteshell Research Area (WRA) of southern Manitoba and of the Atikokan Research Area of northwestern Ontario were investigated to assess their potential role in radionuclide transport within granite fractures of the Canadian Shield. A survey of dissolved organic carbon (DOC) concentrations, carried out to determine the variability in the organic content of these groundwaters, showed average concentrations in WRA deep groundwaters of 0.8 ± 0.1 mg/L for Fracture Zone 2, 0.8 ± 0.4 mg/L for near-vertical fractures, and 2.3 ± 0.8 mg/L for deeper saline groundwater. Surface waters and near-surface groundwaters had significantly higher DOC with 29.2 ± 0.6 mg/L in streams from the East Swamp. The DOC consisted mainly of hydrophilic neutral compounds 60 to 75%, and hydrophobic and hydrophilic acids 23 to 39%, along with very small amounts of hydrophobic bases and neutrals, and hydrophilic bases. The average complexing capacity of natural organics in WRA deep groundwaters was calculated to be 6.7 x 10 -6 eq/L. The ability of these organics to complex radionuclides was tested using conditional stability constants from the literature for humic complex formation with trivalent, tetravalent, pentavalent and hexavalent actinides. The chemistries of Np(V) and U(VI) were predicted to be dominated by inorganic complexes and not significantly affected by organics. Accurate predictions for AM(III) and Th(IV) could not be made since the literature contains a wide range in values of stability constants for humic complexes with these elements. Surface waters and near-surface groundwaters in many areas of the Canadian Shield contain enough humics to complex a significant fraction of dissolved actinides. Radiocarbon ages of humics from WRA groundwater varied between 3600 and 6200 years before present, indicating that a component of humic substances in deep groundwaters must originate from near-surface waters. 54 refs., 15 tabs., 5

  12. Recent developments in identification of kinetic and transport models from experimental data. Contributed Paper IT-08

    International Nuclear Information System (INIS)

    Bhatt, Nirav P.

    2014-01-01

    In this presentation, we will discuss recent developments in area of identification of kinetic and transport models from experimental data, and their importance in spent fuel reprocessing. The traditional kinetic modelling approaches, differentiation and integral methods, will be presented to set the stage. Then, two frameworks of identifying kinetic and transport models will be presented in details. These frameworks can be classified as follows: (i) simultaneous or global model identification (SMI), and (ii) incremental model identification (IMI). In the SMI framework, as name indicates, rate expressions of all reactions are integrated to predict concentrations that are fitted to measured values via a least-squares problem simultaneously. Alternatively, the identification task can be split into a sequence of sub-problems such as the identification of stoichiometry and rate expressions. For each subproblem, the number of model candidates can be kept small. In addition, the information available at a given step can be used to refine the model in subsequent steps. Further, the advantages and disadvantages of these frameworks will be presented

  13. Experimental studies on the transport of silver and cesium fission products in SiC

    International Nuclear Information System (INIS)

    Gerczak, Tyler; Tan, Lizhen; Allen, Todd

    2009-01-01

    To understand the release of Ag and Cs in SiC we have designed an integrated experimental and modeling program to understand the potential role of microstructure on fission product transport. We have encapsulated SiC/Ag and SiC/Cs diffusion couples in a molybdenum canister to ensure contact between the two diffusion couple elements and no Ag or Cs loss to the surrounding environment. The diffusion couples are exposed to temperatures spanning 800 to 1500degC for up to 1000 hrs to simulate normal and the onset of accident conditions. The relationship between the microstructure and diffusion will be understood by employing a variety of techniques such as scanning electron microscopy (SEM), electron backscattered detection (EBSD), energy dispersive spectroscopy (EDS), Rutherford backscattering (RBS), and Raman spectroscopy to characterize morphology, grain boundary character distribution, chemical composition, and crystalline structure. In addition computer modeling is also being used to investigate the diffusion of silver through SiC, but will not be discussed in this paper. A multi-scale approach based on ab initio techniques, molecular dynamics, and continuum rate equations is being pursued to establish relationships between complex microstructures and diffusion rates. Initial work has begun on transport through bulk SiC and on building realistic models of grain boundaries in SiC. (author)

  14. [The assessment of radionuclide contamination and toxicity of soils sampled from "experimental field" site of Semipalatinsk nuclear test site].

    Science.gov (United States)

    Evseeva, T I; Maĭstrenko, T A; Belykh, E S; Geras'kin, S A; Kriazheva, E Iu

    2009-01-01

    Large-scale maps (1:25000) of soil contamination with radionuclides, lateral distribution of 137Cs, 90Sr, Fe and Mn water-soluble compounds and soil toxicity in "Experimental field" site of Semipalatinsk nuclear test site were charted. At present soils from studied site (4 km2) according to basic sanitary standards of radiation safety adopted in Russian Federation (OSPORB) do not attributed to radioactive wastes with respect to data on artificial radionuclide concentration, but they do in compliance with IAEA safety guide. The soils studied can not be released from regulatory control due to radioactive decay of 137Cs and 90Sr and accumulation-decay of 241Am up to 2106 year according to IAEA concept of exclusion, exemption and clearance. Data on bioassay "increase of Chlorella vulgaris Beijer biomass production in aqueous extract from soils" show that the largest part of soils from the studied site (74%) belongs to stimulating or insignificantly influencing on the algae reproduction due to water-soluble compounds effect. Toxic soils occupy 26% of the territory. The main factors effecting the algae reproduction in the aqueous extracts from soil are Fe concentration and 90Sr specific activity: 90Sr inhibits but Fe stimulates algae biomass production.

  15. A combined PHREEQC-2/parallel fracture model for the simulation of laminar/non-laminar flow and contaminant transport with reactions

    Science.gov (United States)

    Masciopinto, Costantino; Volpe, Angela; Palmiotta, Domenico; Cherubini, Claudia

    2010-09-01

    A combination of a parallel fracture model with the PHREEQC-2 geochemical model was developed to simulate sequential flow and chemical transport with reactions in fractured media where both laminar and turbulent flows occur. The integration of non-laminar flow resistances in one model produced relevant effects on water flow velocities, thus improving model prediction capabilities on contaminant transport. The proposed conceptual model consists of 3D rock-blocks, separated by horizontal bedding plane fractures with variable apertures. Particle tracking solved the transport equations for conservative compounds and provided input for PHREEQC-2. For each cluster of contaminant pathways, PHREEQC-2 determined the concentration for mass-transfer, sorption/desorption, ion exchange, mineral dissolution/precipitation and biodegradation, under kinetically controlled reactive processes of equilibrated chemical species. Field tests have been performed for the code verification. As an example, the combined model has been applied to a contaminated fractured aquifer of southern Italy in order to simulate the phenol transport. The code correctly fitted the field available data and also predicted a possible rapid depletion of phenols as a result of an increased biodegradation rate induced by a simulated artificial injection of nitrates, upgradient to the sources.

  16. Histological evolution of the regenerate during bone transport: an experimental study in sheep.

    Science.gov (United States)

    López-Pliego, Esperanza Macarena; Giráldez-Sánchez, Miguel Ángel; Mora-Macías, Juan; Reina-Romo, Esther; Domínguez, Jaime

    2016-09-01

    Bone transport (BT) for segmentary bone defects is a well-known technique as it enables correction with new bone formation, which is similar to the previous bone. Despite the high number of experimental studies of distraction osteogenesis in bone lengthening, the types of ossification and histological changes that occur in the regenerate of the bone transport process remain controversial. The aim of this study is to provide the complete evolution of tissues and the types of ossification in the regenerate during the different phases of bone formation after BT until the end of the remodelling period. A histological study was performed using ten adult sheep that were submitted to BT. The types of ossification as well as the evolution of different tissues in the regenerate were determined using histomorphometry and inmunohistochemical studies. The evolution of trabeculae thickness, osteoblast and osteoclast densities, relationship between collagen types and changes in vascularization were also studied. Ossification was primarily intramembranous, with some focus of endochondral ossification in isolated animals. The cell counts showed a progression of cellular activity from the periphery to the centre, presenting the same progression as the growth of bone trabeculae, whose trabeculae thickness was quadrupled at the end of remodelling. Inmunohistochemical studies confirmed the prevalence of type I collagen and the ratio of the Type I/Type II collagen ratio was found to be 2.48. The percentages of the vascularized areas were proximally higher than distally in all animals, but distal zone obtained higher rates than the central region. Bone transport regenerate exhibits a centripetal ossification model and a mixed pattern with predominance of intramembranous over endochondral ossification. The data obtained resemble partially to those found in models of bone lengthening applied to large animals. This study provides a detailed structural characterization of the newly formed

  17. Changes in mode of travel to work: a natural experimental study of new transport infrastructure.

    Science.gov (United States)

    Heinen, Eva; Panter, Jenna; Mackett, Roger; Ogilvie, David

    2015-06-20

    New transport infrastructure may promote a shift towards active travel, thereby improving population health. The purpose of this study was to determine the effect of a major transport infrastructure project on commuters' mode of travel, trip frequency and distance travelled to work. Quasi-experimental analysis nested within a cohort study of 470 adults working in Cambridge, UK. The intervention consisted of the opening of a guided busway with a path for walking and cycling in 2011. Exposure to the intervention was defined as the negative of the square root of the shortest distance from home to busway. The outcome measures were changes in commute mode share and number of commute trips - both based on a seven-day travel-to-work record collected before (2009) and after (2012) the intervention - and change in objective commute distance. The mode share outcomes were changes in the proportions of trips (i) involving any active travel, (ii) involving any public transport, and (iii) made entirely by car. Separate multinomial regression models were estimated adjusting for commute and sociodemographic characteristics, residential settlement size and life events. Proximity to the busway predicted an increased likelihood of a large (>30 %) increase in the share of commute trips involving any active travel (relative risk ratio [RRR] 1.80, 95 % CI 1.27, 2.55) and a large decrease in the share of trips made entirely by car (RRR 2.09, 95 % CI 1.35, 3.21), as well as a lower likelihood of a small (travel (RRR 0.47, 95 % CI 0.28, 0.81). It was not associated with changes in the share of commute trips involving any public transport, the number of commute trips, or commute distance. The new infrastructure promoted an increase in the share of commuting trips involving active travel and a decrease in the share made entirely by car. Further analysis will show the extent to which the changes in commute mode share were translated into an increase in time spent in active commuting and

  18. Contaminant transport in the sub-surface soil of an uncontrolled landfill site in China: site investigation and two-dimensional numerical analysis.

    Science.gov (United States)

    Xie, Haijian; Chen, Yunmin; Thomas, Hywel R; Sedighi, Majid; Masum, Shakil A; Ran, Qihua

    2016-02-01

    A field investigation of contaminant transport beneath and around an uncontrolled landfill site in Huainan in China is presented in this paper. The research aimed at studying the migration of some chemicals present in the landfill leachate into the surrounding clayey soils after 17 years of landfill operation. The concentrations of chloride and sodium ions in the pore water of soil samples collected at depths up to 15 m were obtained through an extensive site investigation. The contents of organic matter in the soil samples were also determined. A two-dimensional numerical study of the reactive transport of sodium and chloride ion in the soil strata beneath and outside the landfill is also presented. The numerical modelling approach adopted is based on finite element/finite difference techniques. The domain size of approximately 300 × 30 m has been analysed and major chemical transport parameters/mechanisms are established via a series of calibration exercises. Numerical simulations were then performed to predict the long-term behaviour of the landfill in relation to the chemicals studied. The lateral migration distance of the chloride ions was more than 40 m which indicates that the advection and mechanical dispersion are the dominant mechanism controlling the contaminant transport at this site. The results obtained from the analysis of chloride and sodium migration also indicated a non-uniform advective flow regime of ions with depth, which were localised in the first few metres of the soil beneath the disposal site. The results of long-term simulations of contaminant transport indicated that the concentrations of ions can be 10 to 30 times larger than that related to the allowable limit of concentration values. The results of this study may be of application and interest in the assessment of potential groundwater and soil contamination at this site with a late Pleistocene clayey soil. The obtained transport properties of the soils and the contaminant transport

  19. Predicting Transport of 3,5,6-Trichloro-2-Pyridinol Into Saliva Using a Combination Experimental and Computational Approach

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Jordan Ned; Carver, Zana A.; Weber, Thomas J.; Timchalk, Charles

    2017-04-11

    A combination experimental and computational approach was developed to predict chemical transport into saliva. A serous-acinar chemical transport assay was established to measure chemical transport with non-physiological (standard cell culture medium) and physiological (using surrogate plasma and saliva medium) conditions using 3,5,6-trichloro-2-pyridinol (TCPy) a metabolite of the pesticide chlorpyrifos. High levels of TCPy protein binding was observed in cell culture medium and rat plasma resulting in different TCPy transport behaviors in the two experimental conditions. In the non-physiological transport experiment, TCPy reached equilibrium at equivalent concentrations in apical and basolateral chambers. At higher TCPy doses, increased unbound TCPy was observed, and TCPy concentrations in apical and basolateral chambers reached equilibrium faster than lower doses, suggesting only unbound TCPy is able to cross the cellular monolayer. In the physiological experiment, TCPy transport was slower than non-physiological conditions, and equilibrium was achieved at different concentrations in apical and basolateral chambers at a comparable ratio (0.034) to what was previously measured in rats dosed with TCPy (saliva:blood ratio: 0.049). A cellular transport computational model was developed based on TCPy protein binding kinetics and accurately simulated all transport experiments using different permeability coefficients for the two experimental conditions (1.4 vs 0.4 cm/hr for non-physiological and physiological experiments, respectively). The computational model was integrated into a physiologically based pharmacokinetic (PBPK) model and accurately predicted TCPy concentrations in saliva of rats dosed with TCPy. Overall, this study demonstrates an approach to predict chemical transport in saliva potentially increasing the utility of salivary biomonitoring in the future.

  20. Predicting Transport of 3,5,6-Trichloro-2-Pyridinol Into Saliva Using a Combination Experimental and Computational Approach.

    Science.gov (United States)

    Smith, Jordan Ned; Carver, Zana A; Weber, Thomas J; Timchalk, Charles

    2017-06-01

    A combination experimental and computational approach was developed to predict chemical transport into saliva. A serous-acinar chemical transport assay was established to measure chemical transport with nonphysiological (standard cell culture medium) and physiological (using surrogate plasma and saliva medium) conditions using 3,5,6-trichloro-2-pyridinol (TCPy) a metabolite of the pesticide chlorpyrifos. High levels of TCPy protein binding were observed in cell culture medium and rat plasma resulting in different TCPy transport behaviors in the 2 experimental conditions. In the nonphysiological transport experiment, TCPy reached equilibrium at equivalent concentrations in apical and basolateral chambers. At higher TCPy doses, increased unbound TCPy was observed, and TCPy concentrations in apical and basolateral chambers reached equilibrium faster than lower doses, suggesting only unbound TCPy is able to cross the cellular monolayer. In the physiological experiment, TCPy transport was slower than nonphysiological conditions, and equilibrium was achieved at different concentrations in apical and basolateral chambers at a comparable ratio (0.034) to what was previously measured in rats dosed with TCPy (saliva:blood ratio: 0.049). A cellular transport computational model was developed based on TCPy protein binding kinetics and simulated all transport experiments reasonably well using different permeability coefficients for the 2 experimental conditions (1.14 vs 0.4 cm/h for nonphysiological and physiological experiments, respectively). The computational model was integrated into a physiologically based pharmacokinetic model and accurately predicted TCPy concentrations in saliva of rats dosed with TCPy. Overall, this study demonstrates an approach to predict chemical transport in saliva, potentially increasing the utility of salivary biomonitoring in the future. © The Author 2017. Published by Oxford University Press on behalf of the Society of Toxicology. All rights

  1. Mixing and transport during pharmaceutical twin-screw wet granulation: experimental analysis via chemical imaging.

    Science.gov (United States)

    Kumar, Ashish; Vercruysse, Jurgen; Toiviainen, Maunu; Panouillot, Pierre-Emmanuel; Juuti, Mikko; Vanhoorne, Valérie; Vervaet, Chris; Remon, Jean Paul; Gernaey, Krist V; De Beer, Thomas; Nopens, Ingmar

    2014-07-01

    Twin-screw granulation is a promising continuous alternative for traditional batch high shear wet granulation (HSWG). The extent of HSWG in a twin screw granulator (TSG) is greatly governed by the residence time of the granulation materials in the TSG and degree of mixing. In order to determine the residence time distribution (RTD) and mixing in TSG, mostly visual observation and particle tracking methods are used, which are either inaccurate and difficult for short RTD, or provide an RTD only for a finite number of preferential tracer paths. In this study, near infrared chemical imaging, which is more accurate and provides a complete RTD, was used. The impact of changes in material throughput (10-17 kg/h), screw speed (500-900 rpm), number of kneading discs (2-12) and stagger angle (30-90°) on the RTD and axial mixing of the material was characterised. The experimental RTD curves were used to calculate the mean residence time, mean centred variance and the Péclet number to determine the axial mixing and predominance of convective over dispersive transport. The results showed that screw speed is the most influential parameter in terms of RTD and axial mixing in the TSG and established a significant interaction between screw design parameters (number and stagger angle of kneading discs) and the process parameters (material throughput and number of kneading discs). The results of the study will allow the development and validation of a transport model capable of predicting the RTD and macro-mixing in the TSG. These can later be coupled with a population balance model in order to predict granulation yields in a TSG more accurately. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Biofilm formation in an experimental water distribution system: the contamination of non-touch sensor taps and the implication for healthcare.

    Science.gov (United States)

    Moore, Ginny; Stevenson, David; Thompson, Katy-Anne; Parks, Simon; Ngabo, Didier; Bennett, Allan M; Walker, Jimmy T

    2015-01-01

    Hospital tap water is a recognised source of Pseudomonas aeruginosa. U.K. guidance documents recommend measures to control/minimise the risk of P. aeruginosa in augmented care units but these are based on limited scientific evidence. An experimental water distribution system was designed to investigate colonisation of hospital tap components. P. aeruginosa was injected into 27 individual tap 'assemblies'. Taps were subsequently flushed twice daily and contamination levels monitored over two years. Tap assemblies were systematically dismantled and assessed microbiologically and the effect of removing potentially contaminated components was determined. P. aeruginosa was repeatedly recovered from the tap water at levels above the augmented care alert level. The organism was recovered from all dismantled solenoid valves with colonisation of the ethylene propylene diene monomer (EPDM) diaphragm confirmed by microscopy. Removing the solenoid valves reduced P. aeruginosa counts in the water to below detectable levels. This effect was immediate and sustained, implicating the solenoid diaphragm as the primary contamination source.

  3. Processes influencing the transport and fate of contaminated sediments in the coastal ocean: Boston Harbor and Massachusetts Bay

    Science.gov (United States)

    Alexander, P. Soupy; Baldwin, Sandra M.; Blackwood, Dann S.; Borden, Jonathan; Casso, Michael A.; Crusius, John; Goudreau, Joanne; Kalnejais, Linda H.; Lamothe, Paul J.; Martin, William R.; Martini, Marinna A.; Rendigs, Richard R.; Sayles, Frederick L.; Signell, Richard P.; Valentine, Page C.; Warner, John C.; Bothner, Michael H.; Butman, Bradford

    2007-01-01

    Most of the major urban centers of the United States including Boston, New York, Washington, Chicago, New Orleans, Miami, Los Angeles, San Francisco, and Seattle—are on a coast (fig. 1.1). All of these cities discharge treated sewage effluent into adjacent waters. In 2000, 74 percent of the U.S. population lived within 200 kilometers (km) of the coast. Between 1980 and 2002, the population density in coastal communities increased approximately 4.5 times faster than in noncoastal areas of the U.S. (Perkins, 2004). More people generate larger volumes of wastes, increase the demands on wastewater treatment, expand the area of impervious land surfaces, and use more vehicles that contribute contaminants to street runoff. According to the National Coastal Condition Report II (U.S. Environmental Protection Agency, 2005a), on the basis of coastal habitat, water and sediment quality, benthic index, and fish tissue, the overall national coastal condition is only poor to fair and the overall coastal condition in the highly populated Northeast is poor. Scientific information helps managers to prioritize and regulate coastal-ocean uses that include recreation, commercial fishing, transportation, waste disposal, and critical habitat for marine organisms. These uses are often in conflict with each other and with environmental concerns. Developing a strategy for managing competing uses while maintaining sustainability of coastal resources requires scientific understanding of how the coastal ocean system behaves and how it responds to anthropogenic influences. This report provides a summary of a multidisciplinary research program designed to improve our understanding of the transport and fate of contaminants in Massachusetts coastal waters. Massachusetts Bay and Boston Harbor have been a focus of U.S. Geological Survey (USGS) research because they provide a diverse geographic setting for developing a scientific understanding of the geology, geochemistry, and oceanography of

  4. An experimental test plan for the characterization of molten salt thermochemical properties in heat transport systems

    International Nuclear Information System (INIS)

    Calderoni, Pattrick

    2010-01-01

    Molten salts are considered within the Very High Temperature Reactor program as heat transfer media because of their intrinsically favorable thermo-physical properties at temperatures starting from 300 C and extending up to 1200 C. In this context two main applications of molten salt are considered, both involving fluoride-based materials: as primary coolants for a heterogeneous fuel reactor core and as secondary heat transport medium to a helium power cycle for electricity generation or other processing plants, such as hydrogen production. The reference design concept here considered is the Advanced High Temperature Reactor (AHTR), which is a large passively safe reactor that uses solid graphite-matrix coated-particle fuel (similar to that used in gas-cooled reactors) and a molten salt primary and secondary coolant with peak temperatures between 700 and 1000 C, depending upon the application. However, the considerations included in this report apply to any high temperature system employing fluoride salts as heat transfer fluid, including intermediate heat exchangers for gas-cooled reactor concepts and homogeneous molten salt concepts, and extending also to fast reactors, accelerator-driven systems and fusion energy systems. The purpose of this report is to identify the technical issues related to the thermo-physical and thermo-chemical properties of the molten salts that would require experimental characterization in order to proceed with a credible design of heat transfer systems and their subsequent safety evaluation and licensing. In particular, the report outlines an experimental R and D test plan that would have to be incorporated as part of the design and operation of an engineering scaled facility aimed at validating molten salt heat transfer components, such as Intermediate Heat Exchangers. This report builds on a previous review of thermo-physical properties and thermo-chemical characteristics of candidate molten salt coolants that was generated as part

  5. An experimental test plan for the characterization of molten salt thermochemical properties in heat transport systems

    Energy Technology Data Exchange (ETDEWEB)

    Pattrick Calderoni

    2010-09-01

    Molten salts are considered within the Very High Temperature Reactor program as heat transfer media because of their intrinsically favorable thermo-physical properties at temperatures starting from 300 C and extending up to 1200 C. In this context two main applications of molten salt are considered, both involving fluoride-based materials: as primary coolants for a heterogeneous fuel reactor core and as secondary heat transport medium to a helium power cycle for electricity generation or other processing plants, such as hydrogen production. The reference design concept here considered is the Advanced High Temperature Reactor (AHTR), which is a large passively safe reactor that uses solid graphite-matrix coated-particle fuel (similar to that used in gas-cooled reactors) and a molten salt primary and secondary coolant with peak temperatures between 700 and 1000 C, depending upon the application. However, the considerations included in this report apply to any high temperature system employing fluoride salts as heat transfer fluid, including intermediate heat exchangers for gas-cooled reactor concepts and homogenous molten salt concepts, and extending also to fast reactors, accelerator-driven systems and fusion energy systems. The purpose of this report is to identify the technical issues related to the thermo-physical and thermo-chemical properties of the molten salts that would require experimental characterization in order to proceed with a credible design of heat transfer systems and their subsequent safety evaluation and licensing. In particular, the report outlines an experimental R&D test plan that would have to be incorporated as part of the design and operation of an engineering scaled facility aimed at validating molten salt heat transfer components, such as Intermediate Heat Exchangers. This report builds on a previous review of thermo-physical properties and thermo-chemical characteristics of candidate molten salt coolants that was generated as part of the

  6. Implications and concerns of deep-seated disposal of hydrocarbon exploration produced water using three-dimensional contaminant transport model in Bhit Area, Dadu District of Southern Pakistan.

    Science.gov (United States)

    Ahmad, Zulfiqar; Akhter, Gulraiz; Ashraf, Arshad; Fryar, Alan

    2010-11-01

    A three-dimensional contaminant transport model has been developed to simulate and monitor the migration of disposal of hydrocarbon exploration produced water in Injection well at 2,100 m depth in the Upper Cretaceous Pab sandstone, Bhit area in Dadu district of Southern Pakistan. The regional stratigraphic and structural geological framework of the area, landform characteristics, meteorological parameters, and hydrogeological milieu have been used in the model to generate the initial simulation of steady-state flow condition in the underlying aquifer's layers. The geometry of the shallow and deep-seated characteristics of the geological formations was obtained from the drilling data, electrical resistivity sounding surveys, and geophysical well-logging information. The modeling process comprised of steady-state simulation and transient simulation of the prolific groundwater system of contamination transport after 1, 10, 30 years of injection. The contaminant transport was evaluated from the bottom of the injection well, and its short- and long-term effects were determined on aquifer system lying in varying hydrogeological and geological conditions.

  7. Experimentally testing the dependence of momentum transport on second derivatives using Gaussian process regression

    Science.gov (United States)

    Chilenski, M. A.; Greenwald, M. J.; Hubbard, A. E.; Hughes, J. W.; Lee, J. P.; Marzouk, Y. M.; Rice, J. E.; White, A. E.

    2017-12-01

    It remains an open question to explain the dramatic change in intrinsic rotation induced by slight changes in electron density (White et al 2013 Phys. Plasmas 20 056106). One proposed explanation is that momentum transport is sensitive to the second derivatives of the temperature and density profiles (Lee et al 2015 Plasma Phys. Control. Fusion 57 125006), but it is widely considered to be impossible to measure these higher derivatives. In this paper, we show that it is possible to estimate second derivatives of electron density and temperature using a nonparametric regression technique known as Gaussian process regression. This technique avoids over-constraining the fit by not assuming an explicit functional form for the fitted curve. The uncertainties, obtained rigorously using Markov chain Monte Carlo sampling, are small enough that it is reasonable to explore hypotheses which depend on second derivatives. It is found that the differences in the second derivatives of n{e} and T{e} between the peaked and hollow rotation cases are rather small, suggesting that changes in the second derivatives are not likely to explain the experimental results.

  8. Experimental study of fast electron transport in the framework of fast ignition for inertial fusion

    International Nuclear Information System (INIS)

    Vauzour, B.

    2012-01-01

    The framework of this PhD thesis is the validation of the fast ignition scheme for the nuclear fusion by inertial confinement. It consists in the experimental study of the various processes involved in fast electron beams propagation, produced by intense laser pulses (10 19 W.cm -2 ), through dense matter either solid or compressed. In this work we present the results of three experiments carried out on different laser facilities in order to generate fast electron beams in various conditions and study their propagation in different states of matter, from the cold solid to the warm and dense plasma.The first experiment was performed with a high intensity contrast on the UHI100 laser facility (CEA Saclay). The study of fast electron energy deposition inside thin aluminium targets highlights a strong target heating at shallow depths, where the collective effects are predominant, thus producing a steep temperature profile between front (300 eV) and rear (20 eV) sides over 20μm thickness. A numerical simulation of the experiment shows that this temperature gradient induces the formation of a shock wave, breaking through the rear side of the target and thus leading to increase the thermal emission. The experimental chronometry of the shock breakthrough allowed validating the model of the collective transport of electrons.Two other experiments were dedicated to the study of fast electron beam propagation inside compressed targets. In the first experiment on the LULI2000 laser facility, the plane compression geometry allowed to precisely dissociate the energy losses due to resistive effects from those due to the collisional ones. By comparing our experimental results with simulations, we observed a significative increase of the fast electron beam energy losses with the compression and the target heating to temperatures close to the Fermi temperature. The second experiment, performed in a cylindrical geometry, demonstrated a fast electron beam guiding phenomenon due to

  9. Contamination shield

    International Nuclear Information System (INIS)

    Bayer, W.; Pecornik, D.

    1982-01-01

    An acrylate resin is presented as contamination protection coating for components and instruments in nuclear facilities and for spent fuel transport containers. The resin is evaporated or sublimated at 130 0 C and can thus be removed easily from the protected component. The radioactive particles entrained during evaporation are retained by suitable filters. (TK) [de

  10. Outline of experimental schemes for measurements of thermophysical and transport properties in warm dense matter at GSI and FAIR

    International Nuclear Information System (INIS)

    Tauschwitz, Anna; Jacoby, Joachim; Maruhn, Joachim; Basko, Mikhail; Efremov, Vladimir; Iosilevskiy, Igor; Neumayer, Paul; Novikov, Vladimir; Tauschwitz, Andreas; Rosmej, Frank

    2010-01-01

    Different experimental schemes for investigation of warm dense matter produced with intense energetic ion beams are presented. The described target configurations allow direct measurements of thermophysical and transport properties of warm dense matter without hydrodynamic recalculations. The presented experiments will be realized at the current GSI synchrotron SIS-18 and the future FAIR facility in the framework of the WDM-collaboration.

  11. The Experimental Measurement of Local and Bulk Oxygen Transport Resistances in the Catalyst Layer of Proton Exchange Membrane Fuel Cells.

    Science.gov (United States)

    Wang, Chao; Cheng, Xiaojing; Lu, Jiabin; Shen, Shuiyun; Yan, Xiaohui; Yin, Jiewei; Wei, Guanghua; Zhang, Junliang

    2017-12-07

    Remarkable progress has been made in reducing the cathodic Pt loading of PEMFCs; however, a huge performance loss appears at high current densities, indicating the existence of a large oxygen transport resistance associated with the ultralow Pt loading catalyst layer. To reduce the Pt loading without sacrificing cell performance, it is essential to illuminate the oxygen transport mechanism in the catalyst layer. Toward this goal, an experimental approach to measure the oxygen transport resistance in catalyst layers is proposed and realized for the first time in this study. The measuring approach involves a dual-layer catalyst layer design, which consists of a dummy catalyst layer and a practical catalyst layer, followed by changing the thickness of dummy layer to respectively quantify the local and bulk resistances via limiting current measurements combined with linear extrapolation. The experimental results clearly reveal that the local resistance dominates the total resistance in the catalyst layer.

  12. Assessment of the Forward Contamination Risk of Mars by Clean Room Isolates from Space-Craft Assembly Facilities through Aeolian Transport - a Model Study

    Science.gov (United States)

    van Heereveld, Luc; Merrison, Jonathan; Nørnberg, Per; Finster, Kai

    2017-06-01

    The increasing number of missions to Mars also increases the risk of forward contamination. Consequently there is a need for effective protocols to ensure efficient protection of the Martian environment against terrestrial microbiota. Despite the fact of constructing sophisticated clean rooms for spacecraft assembly a 100 % avoidance of contamination appears to be impossible. Recent surveys of these facilities have identified a significant number of microbes belonging to a variety of taxonomic groups that survive the harsh conditions of clean rooms. These microbes may have a strong contamination potential, which needs to be investigate to apply efficient decontamination treatments. In this study we propose a series of tests to evaluate the potential of clean room contaminants to survive the different steps involved in forward contamination. We used Staphylococcus xylosus as model organism to illustrate the different types of stress that potential contaminants will be subjected to on their way from the spacecraft onto the surface of Mars. Staphylococcus xylosus is associated with human skin and commonly found in clean rooms and could therefore contaminate the spacecraft as a result of human activity during the assembling process. The path the cell will take from the surface of the spacecraft onto the surface of Mars was split into steps representing different stresses that include desiccation, freezing, aeolian transport in a Martian-like atmosphere at Martian atmospheric pressure, and UV radiation climate. We assessed the surviving fraction of the cellular population after each step by determining the integrated metabolic activity of the survivor population by measuring their oxygen consumption rate. The largest fraction of the starting culture (around 70 %) was killed during desiccation, while freezing, Martian vacuum and short-term UV radiation only had a minor additional effect on the survivability of Staphylococcus xylosus. The study also included a simulation

  13. Decline in Mycobacterium bovis and Brucella abortus populations during the maturation of experimentally contaminated parmesan-type cheese

    Directory of Open Access Journals (Sweden)

    Karina Ramirez Starikoff

    2016-11-01

    Full Text Available Brazilian legislation allows the manufacture of raw milk cheese with a maturation exceeding 60 days at room temperature above 5°C, but there is a lack of solid scientific evidence on the efficacy of this maturation process in inactivating important pathogens that may be present in milk, such as Mycobacterium bovis and Brucella abortus. Thus, the objectives of this study were to produce parmesan-type cheese experimentally contaminated with M. bovis and B. abortus and evaluate the survival of these pathogens along 2-month maturation. Parmesan-type cheese was manufactured in the laboratory using whole pasteurized milk with or without inoculation with M. bovis (SB1033 or B. abortus (1119-3 and matured at 18°C for up to 63 days. M. bovis was inoculated in Stonebrink-Leslie medium supplemented with antibiotics and incubated at 37°C for 45 days, and B. abortus was incubated in Farrel medium at 36°C for 3 days. The average D18°C value, weighted by variance, was 37.5 ± 5.3 days for M. bovis and 5.9 ± 0.7 days for B. abortus. The average physicochemical parameters in the cheese at the end of the study were as follows: pH = 4.89, water activity = 0.976, and moisture percentage = 43.1%. The pH might have contributed to the reduction in the population of B. abortus but seems not to have influenced the population of M. bovis. We conclude that the duration of the maturation process influences the size of the surviving populations of M. bovis and B. abortus, and that the shortening of the maturation duration might not ensure a decline in pathogen levels to safe levels. Thus, complementary studies considering the effect of several other technological aspects on the survival of these pathogens are required, including the effect of the lactic acid bacterial population, salt content, and temperature of maturation.

  14. Oxidative alteration of uraninite at the Nopal I deposit, Mexico: Possible contaminant transport and source term constraints for the proposed repository at Yucca Mountain

    International Nuclear Information System (INIS)

    Leslie, B.W.; Pearcy, E.C.; Prikryl, J.D.

    1993-01-01

    The Nopal I uranium deposit at Pena Blanca, Mexico is being studied as a natural analog of the proposed high-level nuclear waste repository at Yucca Mountain. Identification of secondary uranium phases at Nopal I, and the sequence of their formation after uraninite oxidation, provides insight into the source term for uranium, and suggests that uranophane may control uranium release and transport in a silici, tuffaceous, chemically oxidizing, and hydrologically unsaturated environment. Possible constraints on contaminant transport at Nopal I are derived from the spatial distribution of uranium and from measurements of 238 U decay-series isotopes. The analyses indicate that flow of U-bearing fluids was influenced strongly by fracture density, but that the flow of these fluids was not restricted to fractures. Gamma spectroscopic measurements of 238 U decay-series isotopes indicates secular equilibrium, which suggests undetectable U transport under present conditions

  15. Change of striatum dopaminergic transporter and content of dopamine in rats with experimental hyperthyroidism

    International Nuclear Information System (INIS)

    Lin Yansong; Wang Huicheng; Zhao Zhiying; Zhu Li; Zhang Yingqiang; Chen Zhengping

    2009-01-01

    Objective: The central dopamine system plays an important role in regulating movement and mood. In our routine clinical practice,we found that patients with hyperthyroidism often show tremor of their hands or legs. Meanwhile they also experienced emotional problems such as anxiety and depression. These reminded us that there might be close relationship between thyroid hormone and dopamine system. Based on our previous works, in this study we evaluated the change of striatum dopamine transporter (DAT) by using 99 Tc m -2β- [N, N'-bis (2-merecaptoethyl) ethylenediamino]methyl, 3β- (4-chlorophenyl) tropane (TRODAT-1) brain biodistribution, and the content of striatum dopamine and its metabolites 3.4-di-hydroxyphenylacetic (DOPAC) by high performace liquid chromatograph-electrochemical detection (HPLC-ECD) in rats with experimental hyperthyroidism. Methods: All 24 rats were randomly divided into two groups, thyroxin group were induced by daily thyroxin infusion for 14 d to be experimental hyperthyroidism, the others were control group which received saline infusion. The blood samples were randomly taken from thyroxine group and control group, and the concentration of TT 3 and TT 4 were detected by radioimmunoassay. After 14 d,both experimental (thyroxine group) and control group were further divided into 2 sub-groups. One was for evaluation of the function of striatum DAT by 99 Tc m -TRODAT-1 biodistribution study and the other was for HPIJC-ECD measurement of the concentration of dopamine and its metabolites DOPAC. Results: Significantly hyperactivity and weight loss [(223.90 ± 8.40) VS (261.60 ± 14.20)g, t=6.98. P 3 and TT 4 after thyroxin infusion was significantly elevated than that of before thyroxin infusion [(2.72 ± 0.29) V8(1.46 ± 0.17) nmol/L, t=10.51, P 3 , and TT 4 after saline infusion showed no statistical significance as compared with before saline infusion [(1.71 ± 0.20) vs (1.54 ± O.09) nmol/L, t=1.68. P>0.05 and (88.38 ± 6.76) vs (98.38 ± 9

  16. Evaluation and Quantification of Uncertainty in the Modeling of Contaminant Transport and Exposure Assessment at a Radioactive Waste Disposal Site

    Science.gov (United States)

    Tauxe, J.; Black, P.; Carilli, J.; Catlett, K.; Crowe, B.; Hooten, M.; Rawlinson, S.; Schuh, A.; Stockton, T.; Yucel, V.

    2002-12-01

    The disposal of low-level radioactive waste (LLW) in the United States (U.S.) is a highly regulated undertaking. The U.S. Department of Energy (DOE), itself a large generator of such wastes, requires a substantial amount of analysis and assessment before permitting disposal of LLW at its facilities. One of the requirements that must be met in assessing the performance of a disposal site and technology is that a Performance Assessment (PA) demonstrate "reasonable expectation" that certain performance objectives, such as dose to a hypothetical future receptor, not be exceeded. The phrase "reasonable expectation" implies recognition of uncertainty in the assessment process. In order for this uncertainty to be quantified and communicated to decision makers, the PA computer model must accept probabilistic (uncertain) input (parameter values) and produce results which reflect that uncertainty as it is propagated through the model calculations. The GoldSim modeling software was selected for the task due to its unique facility with both probabilistic analysis and radioactive contaminant transport. Probabilistic model parameters range from water content and other physical properties of alluvium to the activity of radionuclides disposed to the amount of time a future resident might be expected to spend tending a garden. Although these parameters govern processes which are defined in isolation as rather simple differential equations, the complex interaction of couple processes makes for a highly nonlinear system with often unanticipated results. The decision maker has the difficult job of evaluating the uncertainty of modeling results in the context of granting permission for LLW disposal. This job also involves the evaluation of alternatives, such as the selection of disposal technologies. Various scenarios can be evaluated in the model, so that the effects of, for example, using a thicker soil cap over the waste cell can be assessed. This ability to evaluate mitigation

  17. Three-dimensional analysis of future groundwater flow conditions and contaminant plume transport in the Hanford Site unconfined aquifer system: FY 1996 and 1997 status report

    Energy Technology Data Exchange (ETDEWEB)

    Cole, C.R.; Wurstner, S.K.; Williams, M.D.; Thorne, P.D.; Bergeron, M.P.

    1997-12-01

    A three-dimensional numerical model of groundwater flow and transport, based on the Coupled Fluid Energy, and Solute Transport (CFEST) code, was developed for the Hanford Site to support the Hanford Groundwater Project (HGWP), managed by Pacific Northwest National Laboratory. The model was developed to increase the understanding and better forecast the migration of several contaminant plumes being monitored by the HGWP, and to support the Hanford Site Composite Analysis for low-level waste disposal in the 200-Area Plateau. Recent modeling efforts have focused on continued refinement of an initial version of the three-dimensional model developed in 1995 and its application to simulate future transport of selected contaminant plumes in the aquifer system. This version of the model was updated using a more current version of the CFEST code called CFEST96. Prior to conducting simulations of contaminant transport with the three-dimensional model, a previous steady-state, two-dimensional model of the unconfined aquifer system was recalibrated to 1979 water-table conditions with a statistical inverse method implemented in the CFEST-INV computer code. The results of the recalibration were used to refine the three-dimensional conceptual model and to calibrate it with a conceptualization that preserves the two-dimensional hydraulic properties and knowledge of the aquifer`s three-dimensional properties for the same 1979 water-table conditions. The transient behavior of the three-dimensional flow model was also calibrated by adjusting model storage properties (specific yield) until transient water-table predictions approximated observed water-table elevations between 1979 and 1996.

  18. Three-dimensional analysis of future groundwater flow conditions and contaminant plume transport in the Hanford Site unconfined aquifer system: FY 1996 and 1997 status report

    International Nuclear Information System (INIS)

    Cole, C.R.; Wurstner, S.K.; Williams, M.D.; Thorne, P.D.; Bergeron, M.P.

    1997-12-01

    A three-dimensional numerical model of groundwater flow and transport, based on the Coupled Fluid Energy, and Solute Transport (CFEST) code, was developed for the Hanford Site to support the Hanford Groundwater Project (HGWP), managed by Pacific Northwest National Laboratory. The model was developed to increase the understanding and better forecast the migration of several contaminant plumes being monitored by the HGWP, and to support the Hanford Site Composite Analysis for low-level waste disposal in the 200-Area Plateau. Recent modeling efforts have focused on continued refinement of an initial version of the three-dimensional model developed in 1995 and its application to simulate future transport of selected contaminant plumes in the aquifer system. This version of the model was updated using a more current version of the CFEST code called CFEST96. Prior to conducting simulations of contaminant transport with the three-dimensional model, a previous steady-state, two-dimensional model of the unconfined aquifer system was recalibrated to 1979 water-table conditions with a statistical inverse method implemented in the CFEST-INV computer code. The results of the recalibration were used to refine the three-dimensional conceptual model and to calibrate it with a conceptualization that preserves the two-dimensional hydraulic properties and knowledge of the aquifer's three-dimensional properties for the same 1979 water-table conditions. The transient behavior of the three-dimensional flow model was also calibrated by adjusting model storage properties (specific yield) until transient water-table predictions approximated observed water-table elevations between 1979 and 1996

  19. Multidisciplinary Studies of the Fate and Transport of Contaminants in Ground Water at the U.S. Geological Survey Cape Cod Toxic Substances Hydrology Program Research Site, Massachusetts

    Science.gov (United States)

    Leblanc, D. R.; Smith, R. L.; Kent, D. B.; Barber, L. B.; Harvey, R. W.

    2008-12-01

    The U.S. Geological Survey conducts multidisciplinary research on the physical, chemical, and microbiological processes affecting ground-water contaminants of global concern at its Cape Cod Toxic Substances Hydrology Program site in Massachusetts, USA. The work centers on a 6-kilometer-long plume of treated wastewater in a glacial sand and gravel aquifer. The plume is characterized by distinct geochemical zones caused by the biodegradation of organic materials in treated wastewater that was disposed to the aquifer by rapid infiltration during the period 1936-95. A core group of hydrogeologists, geochemists, microbiologists, and geophysicists has been involved in the research effort for more than two decades. The effort has been enhanced by stable funding, a readily accessible site, a relatively simple hydrologic setting, and logistical support from an adjacent military base. The research team uses a three-part approach to plan and conduct research at the site. First, detailed spatial and temporal monitoring of the plume since the late 1970s provides field evidence of important contaminant-transport processes and provides the basis for multidisciplinary, process-oriented studies. Second, ground-water tracer experiments are conducted in various geochemical zones in the plume to study factors that control the rate and extent of contaminant transport. Several arrays of multilevel sampling devices, including an array with more than 15,000 individual sampling points, are used to conduct these experiments. Plume-scale (kilometers) and tracer-test-scale (1- 100 meters) studies are complemented by laboratory experiments and mathematical modeling of flow and reactive transport. Third, results are applied to the treated-wastewater plume, other contaminant plumes at the military base, and other sites nationally to evaluate the applicability of the findings and to point toward further research. Examples of findings to date include that (1) macrodispersivity can be related to

  20. Experimental proposals for procedures to investigate the water chemistry, sorption and transport properties of marl

    International Nuclear Information System (INIS)

    Bradbury, M.H.; Baeyens, B.; Alexander, W.R.

    1990-11-01

    The aim of this report is to describe a framework within which laboratory studies on groundwater chemistry, sorption and transport properties might be conducted on samples from rock formations being considered as potential 'host rocks' for the disposal of radioactive waste. Here, Valanginian marl, has been taken as a specific example, but the general principles should be applicable to other systems. Some brief notes are given on sampling and handling procedures and mineralogical characterisation. This is followed by a detailed discussion of the procedures considered necessary to determine a groundwater chemistry of a specific rock matrix. The methods described are particularly appropriate to rocks such as marl i.e. low water content rocks (essentially 'dry') with appreciable clay and carbonate contents. An important conclusion drawn is that simple aqueous phase extractions at different liquid to solid ratios, followed by extrapolation procedures, are not always appropriate and can lead to incorrect water compositions. Some of the uncertainties and difficulties inherently involved in determining sorption parameters from batch, infiltration and diffusion based methods are presented. These methods are then individually discussed in greater detail with some illustrative examples. In the relatively few studies where sorption has been measured in crushed rock tests and compared with the results from intact rock experiments, it is often found that there are discrepancies. An outline for an experiment is described in which results from the two types of test could be quantitatively related to one another via cation exchange capacity measurements. Using this method it might be possible to explain the reasons for such discrepancies. Finally, a brief discussion is given on the possible consequences for experimental studies of gas in Valanginian marl and the swelling of the clay rich components. (author) 8 figs., 4 tabs., 46 refs