Resource Type

Chemical Characterization of Soluble Phosphorus Forms along a Hydrologic Flowpath of a Forested Stream Ecosystem (open access)

Chemical Characterization of Soluble Phosphorus Forms along a Hydrologic Flowpath of a Forested Stream Ecosystem

The concentration and distribution of soluble phosphorus (P) forms were determined in compartments of a hydrologic pathway in a forested watershed (Walker Branch, Tennessee). Rainfall, throughfall, soil water, groundwater, stream water, and water from two sites in Melton Hill reservoir downstream of Walker Branch were examined for soluble reactive and total soluble phosphorus (SRP and TSP). Soluble unreactive P (SUP) was determined from their difference. An increase of TSP from rainfall to throughfall indicated leaching or wash off of P from the canopy. SRP and SUP decreased markedly as water percolated through the soil, suggesting biological uptake and/or geochemical adsorption of phosphate groups on soil particles. Changes in soluble P. concentrations within the stream channel supported previous evidence for biological control of P dynamics in Walker Branch. Overall, SUP (an estimate of soluble organic P) constituted a significant fraction of the total soluble P present in each compartment of the flowpath. An analytical technique using high-performance liquid chromatography (HPLC) to separate the inositol phosphates (IP's) was developed and used in characterizing organic P fractions of natural systems. Commercial orthophosphate, inositol monophosphate (IMP), and inositol hexaphosphate (IHP) were adequately separated from each other on Aminex A-27 resin using a sodium chloride/tetrasodium …
Date: January 1, 1999
Creator: Segars, J.E.
System: The UNT Digital Library
Evaluation of Cross-Hole Seismic Tomography for Imaging Low Resistance Intervals and Associated Carbonate Sediments in Coastal Plain Sequences on the Savannah River Site, South Carolina (open access)

Evaluation of Cross-Hole Seismic Tomography for Imaging Low Resistance Intervals and Associated Carbonate Sediments in Coastal Plain Sequences on the Savannah River Site, South Carolina

The objectives of the pilot study were to investigate the limitations of the technique for imaging the presence, extent, and boundaries of the low-resistance intervals and associated carbonate sediments.
Date: January 5, 1999
Creator: Cumbest, R. J.
System: The UNT Digital Library
ARTI refrigerant database (open access)

ARTI refrigerant database

The Refrigerant Database is an information system on alternative refrigerants, associated lubricants, and their use in air conditioning and refrigeration. It consolidates and facilities access to property, compatibility, environmental, safety, application and other information. It provides corresponding information on older refrigerants, to assist manufacturers and those using alternative refrigerants, to make comparisons and determine differences. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern.
Date: January 1, 1999
Creator: Calm, J.M.
System: The UNT Digital Library
Highly Dispersed Pseudo-Homogeneous and Heterogeneous Catalysts Synthesized via Inverse Micelle Solutions for the Liquefaction of Coal (open access)

Highly Dispersed Pseudo-Homogeneous and Heterogeneous Catalysts Synthesized via Inverse Micelle Solutions for the Liquefaction of Coal

The mission of this project was to use inverse micelle solutions to synthesize nanometer sized metal particles and test the particles as catalysts in the liquefaction of coal and other related reactions. The initial focus of the project was the synthesis of iron based materials in pseudo-homogeneous form. The frost three chapters discuss the synthesis, characterization, and catalyst testing in coal liquefaction and model coal liquefaction reactions of iron based pseudo-homogeneous materials. Later, we became interested in highly dispersed catalysts for coprocessing of coal and plastic waste. Bifunctional catalysts . to hydrogenate the coal and depolymerize the plastic waste are ideal. We began studying, based on our previously devised synthesis strategies, the synthesis of heterogeneous catalysts with a bifunctional nature. In chapter 4, we discuss the fundamental principles in heterogeneous catalysis synthesis with inverse micelle solutions. In chapter 5, we extend the synthesis of chapter 4 to practical systems and use the materials in catalyst testing. Finally in chapter 6, we return to iron and coal liquefaction now studied with the heterogeneous catalysts.
Date: January 5, 1999
Creator: Hampden-Smith, M.; Kawola, J. S.; Martino, A.; Sault, A. G. & Yamanaka, S. A.
System: The UNT Digital Library
Geochemistry of Sediment Samples at TA-54, Los Alamos National Laboratory (open access)

Geochemistry of Sediment Samples at TA-54, Los Alamos National Laboratory

A statistical evaluation of sediment data from Technical Area 54, Los Alamos National Laboratory, was used to examine the relation of concentrations of a series of inorganic and radionuclide analytes to general geographic setting and sediment texture. Significant differences exist between results from the north and south sides of Mesita del Buey, with analyte concentrations being generally higher to the north. These differences probably result primarily from variations in background levels in the source materials for the sediments, perhaps reflecting finer particle sizes and/or better developed soils on the north side of the mesa.
Date: January 1, 1999
Creator: Campbell, K. & Reneau, S.L.
System: The UNT Digital Library
Data Decision Analysis: Project Shoal (open access)

Data Decision Analysis: Project Shoal

The purpose of this study was to determine the most appropriate field activities in terms of reducing the uncertainty in the groundwater flow and transport model at the Project Shoal area. The data decision analysis relied on well-known tools of statistics and uncertainty analysis. This procedure identified nine parameters that were deemed uncertain. These included effective porosity, hydraulic head, surface recharge, hydraulic conductivity, fracture correlation scale, fracture orientation, dip angle, dissolution rate of radionuclides from the puddle glass, and the retardation coefficient, which describes the sorption characteristics. The parameter uncertainty was described by assigning prior distributions for each of these parameters. Next, the various field activities were identified that would provide additional information on these parameters. Each of the field activities was evaluated by an expert panel to estimate posterior distribution of the parameters assuming a field activity was performed. The posterior distributions describe the ability of the field activity to estimate the true value of the nine parameters. Monte Carlo techniques were used to determine the current uncertainty, the reduction of uncertainty if a single parameter was known with certainty, and the reduction of uncertainty expected from each field activity on the model predictions. The mean breakthrough time to …
Date: January 1, 1999
Creator: Forsgren, Frank; Pohll, Greg & Tracy, John
System: The UNT Digital Library
Offsite environmental monitoring report on Radiation monitoring around United States nuclear test areas, calendar year 1997 (open access)

Offsite environmental monitoring report on Radiation monitoring around United States nuclear test areas, calendar year 1997

This report describes the Offsite Radiological Environmental Monitoring Program (OREMP) conducted during 1997 by the US Environmental Protection Agency`s (EPAs), Radiation and Indoor Environments National Laboratory, Las Vegas, Nevada. This laboratory operated an environmental radiation monitoring program in the region surrounding the Nevada Test Site (NTS) and at former test sites in Alaska, Colorado, Mississippi, Nevada, and New Mexico. The surveillance program is designed to measure levels and trends of radioactivity, if present, in the environment surrounding testing areas to ascertain whether current radiation levels and associated doses to the general public are in compliance with existing radiation protection standards. The surveillance program additionally has the responsibility to take action to protect the health and well being of the public in the event of any accidental release of radioactive contaminants. Offsite levels of radiation and radioactivity are assessed by sampling and analyzing milk, water, and air; by deploying and reading thermoluminescent dosimeters (TLDs); and using pressurized ionization chambers (PICs) to measure ambient gamma exposure rates with a sensitivity capable of detecting low level exposures not detected by other monitoring methods.
Date: January 1, 1999
Creator: Davis, M. G.; Flotard, R. D.; Fontana, C. A.; Hennessey, P. A.; Maunu, H. K.; Mouck, T. L. et al.
System: The UNT Digital Library
Electric power monthly, January 1999 with data for October 1998 (open access)

Electric power monthly, January 1999 with data for October 1998

The Electric Power Monthly (EPM) presents monthly electricity statistics for a wide audience including Congress, Federal and State agencies, the electric utility industry, and the general public. The purpose of this publication is to provide energy decisionmakers with accurate and timely information that may be used in forming various perspectives on electric issues that lie ahead. The EIA collected the information in this report to fulfill its data collection and dissemination responsibilities as specified in the Federal Energy Administration Act of 1974 (Public Law 93-275) as amended. 1 fig., 63 tabs.
Date: January 1, 1999
Creator: unknown
System: The UNT Digital Library
Seasonal Nutrient Dynamics of Foliage and Litterfall on Walker Branch Watershed, a Deciduous Forest Ecosystem (open access)

Seasonal Nutrient Dynamics of Foliage and Litterfall on Walker Branch Watershed, a Deciduous Forest Ecosystem

A detailed twelve-month study of litterfall, live foliage biomass, and seasonal nutrient (nitrogen, phosphorus, potassium, calcium, sodium, and magnesium) dynamics in tree components was performed for forest types on Walker Branch Watershed, Oak Ridge, Tennessee. Biomass and nutrient content of foliage, reproductive parts and branches were examined for ten dominant trees in order to assess the relative importance of litterfall in returning nutrients to the forest floor in four different forest types. Litterfall, measured in pine, pine-oak-hickory, oak-hickory, and mesophytic hardwood forests, was separated into three components (leaves, reproductive parts, and branches). Seasonal comparisons of those forest types were made for biomass and nutrient inputs for each component and for total litterfall. Each forest types was characterized by total annual input to the forest floor of biomass and individual nutrients for each component as well as total litterfall. Canonical analysis was performed on the yearly totals to test for significant differences among the forest types. Live foliage from the ten predominant species of trees on the watershed, determined by order of total basal area, was analyzed for biomass, nutrient concentration, and changes in nutrient content through the growth season. Seasonal trends for these variables, including the ranking of nutrient concentrations …
Date: January 1, 1999
Creator: Grizzard, T. Henderson, G.S. Clebsch, E.
System: The UNT Digital Library