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Complexation of Actinides in Solution: Thermodynamic Measurementsand Structural Characterization

Description: This paper presents a brief introduction of the studies of actinide complexation in solution at Lawrence Berkeley National Laboratory. An integrated approach of thermodynamic measurements and structural characterization is taken to obtain fundamental understanding of actinide complexation in solution that is of importance in predicting the behavior of actinides in separation processes and environmental transport.
Date: February 1, 2007
Creator: Rao, L.
Partner: UNT Libraries Government Documents Department

Atmospheric Data Package for the Composite Analysis

Description: The purpose of this data package is to summarize our conceptual understanding of atmospheric transport and deposition, describe how this understanding will be simplified for numerical simulation as part of the Composite Analysis (i.e., implementation model), and finally to provide the input parameters needed for the simulations.
Date: September 1, 2005
Creator: Napier, Bruce A. & Ramsdell, James V.
Partner: UNT Libraries Government Documents Department

Suspended sediment transport in the benthic nepheloid layer in southeastern Lake Michigan

Description: Time series observations of water temperature, water transparency, and current velocity were made at four stations located on the lake slope of southeastern Lake Michigan. The observations show that during stratified conditions the benthic nepheloid layer is probably not maintained by the local resuspension of bottom sediment. A more likely source is sediment resuspended further inshore and then transported across the shelf and slope during downwelling events. Internal wave action may be an important source of energy for this transport. Although sediment trap studies suggest that resuspension does occur, it is more likely that increased fluxes observed near the bottom are due to the vertical redistribution of material already in suspension. A benthic nepheloid layer also exists at times during the unstratified period, when occassionally enough energy reaches the bottom to directly resuspend bottom material at the sites.
Date: February 1, 1995
Creator: Hawley, N. & Lesht, B.M.
Partner: UNT Libraries Government Documents Department

STREAM2 Revision 1: An aqueous release emergency response model

Description: This report documents the revision for STREAM2 code and its input files. STREAM2 is an aqueous transport module of the WIND system. As requested by the Emergency Response Department, two surface aqueous release locations (McQueen Branch and Tims Branch) were added in the STREAM2 code. In addition, the revised STREAM2 has the capability to vary the channel-segment volume based on channel flow to better represent the open channel hydraulics. Thus, the updated version of STREAM2 improves the contaminant transport calculation
Date: April 14, 2000
Creator: Chen, K.F.
Partner: UNT Libraries Government Documents Department

A modified invasion percolation model for low-capillary number immiscible displacements in horizontal rough-walled fractures: Influence of local in-plane

Description: The authors develop and evaluate a modified invasion percolation (MIP) model for quasi-static immiscible displacement in horizontal fractures. The effects of contact angle, local aperture field geometry, and local in-plane interracial curvature between phases are included in the calculation of invasion pressure for individual sites in a discretized aperture field. This pressure controls the choice of which site is invaded during the displacement process and hence the growth of phase saturation structure within the fracture. To focus on the influence of local in-plane curvature on phase invasion structure, they formulate a simplified nondimensional pressure equation containing a dimensionless curvature number (C) that weighs the relative importance of in-plane curvature and aperture-induced curvature. Through systematic variation of C, they find in-plane interracial curvature to greatly affect the phase invasion structure. As C is increased from zero, phase invasion fronts transition from highly complicated (IP results) to microscopically smooth. In addition, measurements of fracture phase saturations and entrapped cluster statistics (number, maximum size, structural complication) show differential response between wetting and nonwetting invasion with respect to C that is independent of contact angle hysteresis. Comparison to experimental data available at this time substantiates predicted behavior.
Date: January 28, 2000
Partner: UNT Libraries Government Documents Department

Visualization of micro-scale phase displacement processes in retention and outflow experiments: Non-uniqueness of unsaturated flow properties

Description: Methods to determine unsaturated hydraulic properties can exhibit random and non-unique behavior. The authors assess the causes for these behaviors by visualizing micro-scale phase displacement processes during equilibrium retention and transient outflow experiments. They observe that the drainage process is composed of a fast fingering followed by a slower backfilling. The influence of each these processes is controlled by the size and the speed of the applied boundary step, the initial saturation and its structure and by small-scale heterogeneities. Because the mixture of these micro-scale processes yields macro-scale effective behavior, measured unsaturated flow properties are also a function of these controls. These results suggest limitations on the current definitions and uniqueness of unsaturated hydraulic properties.
Date: March 9, 2000
Partner: UNT Libraries Government Documents Department

Factors controlling satiated relative permeability in a partially-saturated horizontal fracture

Description: Recent work demonstrates that phase displacements within horizontal fractures large with respect to the spatial correlation length of the aperture field lead to a satiated condition that constrains the relative permeability to be less than one. The authors use effective media theory to develop a conceptual model for satiated relative permeability, then compare predictions to existing experimental measurements, and numerical solutions of the Reynolds equation on the measured aperture field within the flowing phase. The close agreement among all results and data show that for the experiments considered here, in-plane tortuosity induced by the entrapped phase is the dominant factor controlling satiated relative permeability. They also find that for this data set, each factor in the conceptual model displays an approximate power law dependence on the satiated saturation of the fracture.
Date: February 16, 2000
Partner: UNT Libraries Government Documents Department

Reductive dissolution and metal transport in lake coeur d alenesediments

Description: The benthic sediments in Lake Coeur d Alene, northern Idaho,have been contaminated by metals (primarily Zn, Pb, and Cu) from decadesof upstream mining activities. As part of ongoing research on thebiogeo-chemical cycling of metals in this area, a diffusivereactive-transport model has been developed to simulate metal transportin the lake sediments. The model includes 1-D inorganic diffusivetransport coupled to a biotic reaction network with multiple terminalelectron acceptors under redox disequilibrium conditions. Here, the modelis applied to evaluate the competing effects of heavy-metal mobilizationthrough biotic reductive dissolution of Fe(III) (hydr)oxides, andimmobilization as biogenic sulfide minerals. Results indicate that therelative rates of Fe and sulfate reduction could play an important rolein metal transport through the envi-ronment, and that the formation of(bi)sulfide complexes could significantly enhance metal solubility, aswell as desorption from Fe hydroxides.
Date: April 27, 2007
Creator: Sengor, Sevinc.S.; Spycher, Nicolas.F.; Ginn, Timothy.R.; Moberly, James; Peyton, B. & Sani, Rajesh.K.
Partner: UNT Libraries Government Documents Department

Basic Research Needs for Geosciences: Facilitating 21st Century Energy Systems

Description: To identify research areas in geosciences, such as behavior of multiphase fluid-solid systems on a variety of scales, chemical migration processes in geologic media, characterization of geologic systems, and modeling and simulation of geologic systems, needed for improved energy systems.
Date: June 1, 2007
Creator: DePaolo, D. J.; Orr, F. M.; Benson, S. M.; Celia, M.; Felmy, A.; Nagy, K. L. et al.
Partner: UNT Libraries Government Documents Department

SRNL Emergency Response Capability for Atmospheric Contaminant Releases

Description: Emergency response to an atmospheric release of chemical or radiological contamination is enhanced when plume predictions, field measurements, and real-time weather information are integrated into a geospatial framework. The Weather Information and Display (WIND) System at Savannah River National Laboratory (SRNL) utilizes such an integrated framework. The rapid availability of predictions from a suite of atmospheric transport models within this geospatial framework has proven to be of great value to decision makers during an emergency involving an atmospheric contaminant release.
Date: July 12, 2006
Creator: Koffman, L.; Chuck Hunter, C.; Robert Buckley, R. & Robert Addis, R.
Partner: UNT Libraries Government Documents Department


Description: The Florida Footprint experiments were a series of field programs in which perfluorocarbon tracers were released in different configurations centered on a flux tower to generate a data set that can be used to test transport and dispersion models. These models are used to determine the sources of the CO{sub 2} that cause the fluxes measured at eddy covariance towers. Experiments were conducted in a managed slash pine forest, 10 km northeast of Gainesville, Florida, in 2002, 2004, and 2006 and in atmospheric conditions that ranged from well mixed, to very stable, including the transition period between convective conditions at midday to stable conditions after sun set. There were a total of 15 experiments. The characteristics of the PFTs, details of sampling and analysis methods, quality control measures, and analytical statistics including confidence limits are presented. Details of the field programs including tracer release rates, tracer source configurations, and configuration of the samplers are discussed. The result of this experiment is a high quality, well documented tracer and meteorological data set that can be used to improve and validate canopy dispersion models.
Date: January 1, 2007
Creator: WATSON,T.B.; DIETZ, R.N.; WILKE, R.; HENDREY, G.; LEWIN, K.; NAGY, J. et al.
Partner: UNT Libraries Government Documents Department


Description: Matrix diffusion can significantly retard solute transport in fractured formations. Understanding matrix diffusion is crucial for predicting the arrival time, peak concentration, and tail of a contaminant breakthrough curve. Previous studies show that the effective matrix diffusion coefficient may be scale dependent. This study examines how heterogeneities of diffusion properties affect the effective matrix diffusion coefficient. Two types of heterogeneity in a channelized flow system are considered in the study: (1) interchannel heterogeneity, and (2) intrachannel heterogeneity. The objectives of this study are (1) to examine if it is appropriate to use a single, effective matrix diffusion coefficient in a standard solution model to predict breakthrough curves (BTC) in a fractured formation, (2) if so, how this effective value is related to the degree of the matrix diffusion coefficient variability; and (3) to examine if the observed scale dependence of the effective matrix-diffusion coefficient is caused by heterogeneity in diffusion properties. The results show that the use of a single effective matrix diffusion coefficient is appropriate only if the inter- and intrachannel variability of diffusion properties is small. The scale dependence of the effective matrix diffusion coefficient is not caused by either type of the studied heterogeneity.
Date: September 7, 2005
Creator: Zhang, Y.; Liu, H.; Zhou, Q. & Finsterle, S.
Partner: UNT Libraries Government Documents Department

Using DUSTRAN to Simulate Fog-Oil Dispersion and Its Impacts on Local Insect Populations at Ft. Hood: Final Report

Description: Smokes and obscurants (S&O) are important screening agents used during military training exercises on many military installations. Although the use of S&O is subject to environmental laws, the fate and effects of S&O on natural habitats are not well documented. One particular concern is the impact S&O may have on local insect populations, which can be important components of terrestrial food chains of endangered species. Fog-oil (FO) is an S&O that is of particular concern. An important part of assessing potential ecosystem impacts is the ability to predict downwind FO concentrations. This report documents the use of the comprehensive atmospheric dispersion modeling system DUST TRANsport (DUSTRAN) to simulate the downwind transport and diffusion of a hypothetical FO release on the U.S. Army installation at Ft. Hood, TX.
Date: December 29, 2006
Creator: Rishel, Jeremy P.; Chapman, Elaine G.; Rutz, Frederick C. & Allwine, K Jerry
Partner: UNT Libraries Government Documents Department

Urban Dispersion Program Overview and MID05 Field Study Summary

Description: The Urban Dispersion Program (UDP) was a 4-year project (2004–2007) funded by the U.S. Department of Homeland Security with additional support from the Defense Threat Reduction Agency. The U.S. Environmental Protection Agency (EPA) also contributed to UDP through funding a human-exposure component of the New York City (NYC) field studies in addition to supporting an EPA scientist in conducting modeling studies of NYC. The primary goal of UDP was to improve the scientific understanding of the flow and diffusion of airborne contaminants through and around the deep street canyons of NYC. The overall UDP project manager and lead scientist was Dr. Jerry Allwine of Pacific Northwest National Laboratory. UDP had several accomplishments that included conducting two tracer and meteorological field studies in Midtown Manhattan.
Date: July 31, 2007
Creator: Allwine, K Jerry & Flaherty, Julia E.
Partner: UNT Libraries Government Documents Department

Addendum for the Phase I Hydrologic Data for the Groundwater Flow and Contaminant Transport Model of Corrective Action Unit 97: Yucca Flat/Climax Mine, Nevada Test Site, Nye County, Nevada, Revision 0 (page changes)

Description: This document, which makes changes to Phase I Hydrologic Data for the Groundwater Flow and Contaminant Transport Model of Corrective Action Unit 97: Yucca Flat/Climax Mine, Nevada Test Site, Nye County, Nevada, S-N/99205--077, Revision 0 (June 2006), was prepared to address review comments on this final document provided by the Nevada Division of Environmental Protection (NDEP) in a letter dated August 4, 2006. The document includes revised pages that address NDEP review comments and comments from other document users. Change bars are included on these pages to identify where the text was revised. In addition to the revised pages, the following clarifications are made for the two plates inserted in the back of the document: • Plate 4: Disregard the repeat of legend text ‘Drill Hole Name’ and ‘Drill Hole Location’ in the lower left corner of the map. • Plate 6: The symbol at the ER-16-1 location (white dot on the lower left side of the map) is not color-coded because no water level has been determined. The well location is included for reference. • Plate 6: The symbol at the ER-12-1 location (upper left corner of the map), a yellow dot, represents the lower water level elevation. The higher water level elevation, represented by a red dot, was overprinted.
Date: May 1, 2007
Creator: McCord, John
Partner: UNT Libraries Government Documents Department

Final Report to the Subsurface Science Program - Impact of Measurement Instrument and Conceptual Model on Analysis of Subsurface Heterogeneity

Description: This final report covers results of research initially focused on particle transport and then extended to study of measurement scale and scaling. Experimental, numerical, and theoretical findings were published in the areas of hydraulics in heterogeneous media, particle-chemical-microbial transport in heterogeneous media, sampling design, stochastics and wellhead protection. This work has resulted in 17 journal publications, a number of conference presentations, two Ph.D. dissertations, two Master's theses, and two manuscripts upon which undergraduate students have been co-authors.
Date: January 10, 2003
Creator: Silliman, Stephen E.
Partner: UNT Libraries Government Documents Department

Measurement and Improved Understanding of Vertical Transport and the Evaluation of these Processes in Mesoscale Models

Description: The NCAR effort is primarily focused on the analysis of a diverse suite of measurements taken at the southern end of the Salt Lake City Valley within the Jordan Narrows. These measurements include wind profiler, surface, lidar, radiosonde, multi-layered tether-sonde and sodar measurements. We are also collaborating with other VTMX investigators through linking our measurements within the Jordan Narrows with their investigations. The instrumentation was provided to interested VTMX investigators and was used extensively. Thus the NCAR data set played a large role in the results of the overall experiment. Our work under this proposal includes analysis of the observations, mesoscale modeling efforts in support of our VTMX analysis and general instrumentation development aimed at improving the measurement of vertical transport and mixing under stable conditions. This report is subdivided by research objectives.
Date: February 13, 2007
Creator: Parsons, David; Pinto, James; Brown, William; Cohn, Stephen & Morley, Bruce
Partner: UNT Libraries Government Documents Department