20 Matching Results

Search Results

Development and Operation of a Passive-Flow Treatment System for (Sup 90)Sr-Contaminated Groundwater

Description: Seep C was a free-flowing stream of groundwater that emerged in a narrow valley below the old low-level waste (LLW) disposal trenches in Solid Waste Storage Area 5 (SWSA 5) at Oak Ridge National Laboratory (ORNL). The flow rate of the seep water was strongly influenced by rainfall, and typically ranged from 0.5 to 8 L/min. The seep water entered Melton Branch, a small stream that joins White Oak Creek before exiting the ORNL boundary. The seep water contained high concentrations of {sup 90}Sr (10,000 to 20,000 Bq/L) and, before the full-scale treatment system was installed, contributed about 25% of all the {sup 90}Sr leaving ORNL. Seep C was identified as a primary source of off-site contaminant transport and was designated for an early removal action under the Comprehensive Environmental Response and Liability Act (CERCLA). A passive flow treatment system was chosen as the most cost-effective method for treating the water.
Date: February 28, 1999
Creator: Kirkham, P.S. & Taylor, P.A.
Partner: UNT Libraries Government Documents Department

Effects of Platinum Additions and Sulfur Impurities on the Microstructure and Scale Adhesion Behavior of Single-Phase CVD Aluminide Bond Coatings

Description: The adhesion of alumina scales to aluminide bond coats is a life-limiting factor for some advanced thermal barrier coating systems. This study investigated the effects of aluminide bond coat sulfur and platinum contents on alumina scale adhesion and coating microstructural evolution during isothermal and cyclic oxidation testing at 1150 C. Low-sulfur NiAl and NiPtAl bond coats were fabricated by chemical vapor deposition (CVD). Lowering the sulfur contents of CVD NiAl bond coatings significantly improved scale adhesion, but localized scale spallation eventually initiated along coating grain boundaries. Further improvements in scale adhesion were obtained with Pt additions. The observed influences of Pt additions included: (1) mitigation of the detrimental effects of high sulfur levels, (2) drastic reductions in void growth along the scale-metal interface, (3) alteration of the oxide-metal interface morphology, and (4) elimination of Ta-rich oxides in the Al{sub 2}O{sub 3} scales during thermal cycling. The results of this study also suggested that the microstructure (especially the grain size) of CVD aluminide bond coatings plays a significant role in scale adhesion.
Date: February 28, 1999
Creator: Cooley, K.M.; Haynes, J.A.; Lee, W.Y.; Pint, B.A.; Wright, I.G. & Zhang, Y.
Partner: UNT Libraries Government Documents Department

The Life Cycle Analysis Toolbox

Description: The life cycle analysis toolbox is a valuable integration of decision-making tools and supporting materials developed by Oak Ridge National Laboratory (ORNL) to help Department of Energy managers improve environmental quality, reduce costs, and minimize risk. The toolbox provides decision-makers access to a wide variety of proven tools for pollution prevention (P2) and waste minimization (WMin), as well as ORNL expertise to select from this toolbox exactly the right tool to solve any given P2/WMin problem. The central element of the toolbox is a multiple criteria approach to life cycle analysis developed specifically to aid P2/WMin decision-making. ORNL has developed numerous tools that support this life cycle analysis approach. Tools are available to help model P2/WMin processes, estimate human health risks, estimate costs, and represent and manipulate uncertainties. Tools are available to help document P2/WMin decision-making and implement programs. Tools are also available to help track potential future environmental regulations that could impact P2/WMin programs and current regulations that must be followed. An Internet-site will provide broad access to the tools.
Date: February 28, 1999
Creator: Bishop, L.; Tonn, B.E.; Williams, K.A.; Yerace, P. & Yuracko, K.L.
Partner: UNT Libraries Government Documents Department

Atom Probe Field Ion Microscopy of Zr-Doped Polysynthetically Twinned Titanium Aluminide

Description: Interracial segregation and partitioning in a polysynthetically twinned Ti-48.4 at.% Al-0.6% Zr alloy were investigated by atom probe field ion microscopy and atom probe tomography. The compositions of the {gamma} and {alpha}{sub 2} phases were determined to be Ti-47.5% Al-O.71% Zr-0.06% O and Ti-31.6% Al-0.68% Zr-2.4% O, respectively. These results indicate a high concentration of zirconium in both matrix phases, confirming a strength increase through solid-solution strengthening, but no significant zirconium partitioning to either phase. Although zirconium additions produced a refined lamellar microstructure in this material, compositional analysis of {gamma}/{gamma} and {gamma}/{alpha}{sub 2} interfaces showed no evidence of significant zirconium segregation. This suggests that zirconium additions may produce a refined lamellar microstructure, but may not be effective at providing resistance to growth and coarsening.
Date: February 28, 1999
Creator: Inui, H.; Larson, D.J.; Miller, M.K. & Yamaguchi, M.
Partner: UNT Libraries Government Documents Department

Liquid Permeability Measurements in Solidifying Aluminum-Copper Alloys

Description: Measurements of liquid permeability in the mushy zones of AI-15.42% Cu and Al-8.68% Cu alloy samples have been performed isothermally just above the eutectic temperature, using eutectic liquid as the fluid. A modified method has been developed to determine the specific permeability, K{sub s}, as a function of time during the test from the data collected on these alloys. Factors affecting permeability measurements are discussed. Permeabilities are observed to vary throughout the experiment. This is attributed to microstructural coarsening and channeling that occurs in the sample during the experiment. The permeability is related to the microstructure of the sample using the Kozeny-Carman equation. The correlation between the measured K{sub s}, liquid fraction, g{sub L} and the specific solid surface area, S{sub v}, improves markedly when compared to previous studies in which microstructural coarsening was ignored.
Date: February 28, 1999
Creator: Duncan, A.J.; Han, Q. & Viswanathan, S.
Partner: UNT Libraries Government Documents Department

Mercury Removal from Waste Organics

Description: Mercury was effectively removed from the oil via sorption using SAMMS.The method was demonstrated on a large scale using ORNL waste oil contaminated with mercury. This technology is ready for further demonstration and implementation when the SAMMS material is available in large quantities.
Date: February 28, 1999
Creator: Cummins, R.L.; Klasson, T. & Taylor, P.A.
Partner: UNT Libraries Government Documents Department

Hot Corrosion of Nickel-Base Alloys in Biomass-Derived Fuel Simulated Atmosphere

Description: Biomass fuels are considered to be a promising renewable source of energy. However, impurities present in the fuel may cause corrosion problems with the materials used in the hot sections of gas turbines and only limited data are available so far. As part of the Advanced Turbine Systems Program initiated by the U.S. Department of Energy, the present study provides initial data on the hot corrosion resistance of different nickel-base alloys against sodium sulfate-induced corrosion as a baseline, and against salt compositions simulating biomass-derived fuel deposits. Single crystal nickel-superalloy Rene N5, a cast NiCrAlY alloy, a NiCoCrAlY alloy representing industrially used overlay compositions, and a model {beta}NiAl+Hf alloy were tested in 1h thermal cycles at 950 C with different salt coatings deposited onto the surfaces. Whereas the NiCoCrAlY alloy exhibited reasonable resistance against pure sodium sulfate deposits, the NiCrAiY alloy and Rene N5 were attacked severely. Although considered to be an ideal alumina former in air and oxygen at higher temperatures, {beta}NiAl+Hf also suffered from rapid corrosion attack at 950 C when coated with sodium sulfate. The higher level of potassium present in biomass fuels compared with conventional fuels was addressed by testing a NiCoCrAlY alloy coated with salts of different K/Na atomic ratios. Starting at zero Na, the corrosion rate increased considerably when sodium was added to potassium sulfate. In an intermediate region the corrosion rate was initially insensitive to the K/Na ratio but accelerated when very Na-rich compositions were deposited. The key driver for corrosion of the NiCoCrAlY alloy was sodium sulfate rather than potassium sulfate, and no simple additive or synergistic effect of combining sodium and potassium was found.
Date: February 28, 1999
Creator: Leyens, C.; Pint, B.A. & Wright, I.G.
Partner: UNT Libraries Government Documents Department

A Life Cycle Analysis System to Support D and D, Pollution Prevention, and Asset Recovery

Description: This paper describes a life cycle analysis system (LCAS) developed to support US Department of Energy (DOE) decision-making regarding deactivation and decommissioning (D and D), pollution prevention (P2), and asset recovery, and its deployment to analyze the disposition of facilities and capital assets. Originally developed for use at the Oak Ridge East Tennessee Technology Park, this approach has been refined through application at Ohio Operations Office sites and is now being deployed at a number of DOE sites. Programs such as National Metals Recycle, the D and D Focus Area, P2, and Asset Utilization are successfully using the system to make better decisions resulting in lower cost to the taxpayer and improved environmental quality. The LCAS consists of a user-friendly, cost-effective, and analytically-sound decision-aiding process and a complementary suite of automated tools to handle data administration and multiple criteria life cycle analysis (LCA). LCA is a systematic and comprehensive process for identifying, assessing, and comparing alternatives for D and D, P2, and asset recovery at government sites, and for selecting and documenting a preferred alternative. An LCA includes all of the impacts (benefits and costs) that result from a course of action over the entire period of time affected by the action. The system also includes visualizations that aid communication and help make decision-making transparent. The LCAS has three major components related to data collection, decision alternative assessment, and making the decisions. Each component is discussed in-depth using the example of deployment of the LCAS to support asset recovery.
Date: February 28, 1999
Creator: Bishop, L.; Tonn, B.E. & Yuracko, K.L.
Partner: UNT Libraries Government Documents Department

Projection Methods for Interdendritic Flows

Description: In spite of recent advances in the mathematical modeling of fluid dynamics for materials processing applications, no significant advances have been made in the numerical discretization of these equations. In this work, the application of two-step projection methods for the numerical simulation of interdendritic flows is, discussed. Unlike previous methods, the methods presented here are constructed for the exact equations which are characterized by variable density and volumetric fraction of the liquid. The drag terms, which describe the momentum loss due to the flow around and through the dendrite structures, are treated implicitly. Numerical examples for shrinkage-induced flow during solidification of an AI-4.5% Cu alloy bar is used to illustrate the effectiveness of the proposed algorithm.
Date: February 28, 1999
Creator: Han, Q.; Sabau, A.S. & Viswanathan, S.
Partner: UNT Libraries Government Documents Department

Surface Engineering of Silicon and Carbon by Pulsed-Laser Ablation

Description: Experiments are described in which a focused pulsed-excimer laser beam is used either to ablate a graphite target and deposit hydrogen-free amorphous carbon films, or to directly texture a silicon surface and produce arrays of high-aspect-ratio silicon microcolumns. In the first case, diamond-like carbon (or tetrahedral amorphous carbon, ta-C) films were deposited with the experimental conditions selected so that the masses and kinetic energies of incident carbon species were reasonably well controlled. Striking systematic changes in ta-C film properties were found. The sp{sup 3}-bonded carbon fraction, the valence electron density, and the optical (Tauc) energy gap ail reach their maximum values in films deposited at a carbon ion kinetic energy of {approximately}90 eV. Tapping-mode atomic force microscope measurements also reveal that films deposited at 90 eV are extremely smooth (rms roughness {approximately}1 {angstrom} over several hundred nm) and relatively free of particulate, while the surface roughness increases in films deposited at significantly lower energies. In the second set of experiments, dense arrays of high-aspect-ratio silicon microcolumns {approximately}20-40 {micro}m tall and {approximately}2 {micro}m in diameter were formed by cumulative nanosecond pulsed excimer laser irradiation of silicon wafers in air and other oxygen-containing atmospheres. It is proposed that microcolumn growth occurs through a combination of pulsed-laser melting of the tips of the columns and preferential redeposition of silicon on the molten tips from the ablated flux of silicon-rich vapor. The common theme in this research is that a focused pulsed-laser beam can be used quite generally to create an energetic flux, either the energetic carbon ions needed to form sp{sup 3} (diamond-like) bonds or the overpressure of silicon-rich species needed for microcolumn growth. Thus, new materials synthesis opportunities result from the access to nonequilibrium growth conditions provided by pulsed-laser ablation.
Date: February 28, 1999
Creator: Fowlkes, J.D.; Geohegan, D.B.; Jellison, G.E., Jr.; Lowndes, D.H.; Merkulov, V.I.; Pedraza, A.J. et al.
Partner: UNT Libraries Government Documents Department

Rapid Sampling from Sealed Containers

Description: The authors have developed several different types of tools for sampling from sealed containers. These tools allow the user to rapidly drill into a closed container, extract a sample of its contents (gas, liquid, or free-flowing powder), and permanently reseal the point of entry. This is accomplished without exposing the user or the environment to the container contents, even while drilling. The entire process is completed in less than 15 seconds for a 55 gallon drum. Almost any kind of container can be sampled (regardless of the materials) with wall thicknesses up to 1.3 cm and internal pressures up to 8 atm. Samples can be taken from the top, sides, or bottom of a container. The sampling tools are inexpensive, small, and easy to use. They work with any battery-powered hand drill. This allows considerable safety, speed, flexibility, and maneuverability. The tools also permit the user to rapidly attach plumbing, a pressure relief valve, alarms, or other instrumentation to a container. Possible applications include drum venting, liquid transfer, container flushing, waste characterization, monitoring, sampling for archival or quality control purposes, emergency sampling by rapid response teams, counter-terrorism, non-proliferation and treaty verification, and use by law enforcement personnel during drug or environmental raids.
Date: February 28, 1999
Creator: Johnston, R.G.; Garcia, A.R.E.; Martinez, R.K. & Baca, E.T.
Partner: UNT Libraries Government Documents Department

HEMISPHERIC CENTER FOR ENVIRONMENTAL TECHNOLOGY

Description: Search for decontamination technologies to be assessed at FIU-HCET continues. Bartlett Nuclear Inc. returned to FIU-HCET on February 15-19, 1999, to complete the demonstration of coating removal from concrete ceiling and aggressive contamination removal on uncoated concrete wall using their Robotic Climber. The design of test beds for large-scale technology demonstration of blockage locating and pipe unplugging has undergone major revision. The lab-scale test loop is also under modification. A new sampling system using isokinetic principles and consisting of thermistors, flow controller, and Wheatstone bridge will be installed on the flow loop. FIU-HCET International Coordinator attended the VII Steering Committee meeting in Lima, Peru, on February 11-12, 1999, and successfully introduced the Interactive Communication Website. Additional agenda items on the Website were proposed by the Steering Committee for upcoming committee meetings and working groups.
Date: February 28, 1999
Creator: M.A.Ebadian
Partner: UNT Libraries Government Documents Department

THE MURMANSK INITIATIVE - RF: 1994-1999 NEARING THE FINISH LINE.

Description: ''The Murmansk Initiative - RF'' is a tri-lateral project developed to support Russia's ability to meet the London Convention's prohibition on ocean disposal of radioactive waste. The Initiative, under a tripartite agreement, has upgraded an existing low-level liquid radioactive waste treatment facility, increasing capacity from 1,200 m{sup 3}/year to 5,000 m{sup 3}/year, and expanded capability to treat liquids containing salt (up to 10 g/L). The three parties to the agreement, the Russian Federation, Norway, and the United States, have all contributed the project. All construction has been provided by Russia. Construction of mechanical systems (piping and valves, pumps, sorbent columns, settling tanks, and surge tanks) is nearing completion, with instrumentation and control (I&C) systems currently being installed. Delays to the I&C installation have occurred because changes in system specifications required additional U.S. supplied computer control equipment to be purchased, and clearance through customs (both U.S. and Russian) has been slow. Start-up testing has been limited to testing of isolated sub-systems because of the delays in the I&C installation. The current state of the Russian economy and completion of a cementation unit, which was not part of the original tri-partite agreement, have hampered final construction activities. Russian regulatory authorities have stated that final licensing for expanded capacity (5,000 m{sup 3}/year) would not be given until the cementation unit was on-line. Completion of the project is now scheduled for August 1999.
Date: February 28, 1999
Creator: BOWERMAN,B.; CZAJKOWSKI,C. & DYER,R.S.
Partner: UNT Libraries Government Documents Department

Parametric Optimization of the MEO Process for Treatment of Mixed Waste Residues

Description: A series of bench-scale experiments were conducted to determine the optimum reaction conditions for destruction of styrene-divinyl benzene based cation resin and methylene chloride by the mediated electrochemical oxidation (MEO) process. Reaction parameters examined include choice of electron transfer mediator, reaction temperature and solvent system. For the cation exchange resins, maximum destruction efficiencies were obtained using cerium (IV) as mediator in nitric acid at a temperature of 70 C. Reasonable efficiencies were also realized with silver(II) and cobalt (III) at ambient temperature in the same solvent. Use of sulfuric acid as the solvent yielded much lower efficiencies under equivalent conditions. Methylene chloride was found to react only with silver (II) at ambient temperature in nitric acid media, cobalt (III) and cerium (IV) were totally ineffective. These results demonstrate a need to perform bench-scale experiments to determine optimum operating conditions for each organic substrate targeted for treatment by the MEO process.
Date: February 28, 1999
Creator: Cournoyer, M. E. & Smith, W. H.
Partner: UNT Libraries Government Documents Department

Overview of DOE'S programs on aluminum and magnesium for automotive application

Description: The U.S. Department of Energy will present an update and review of its programs in aluminum and magnesium for automotive and heavy-duty vehicle applications. While the main programs focused on vehicle materials are in the Office of Transportation Technologies, contributing efforts will be described in the DOE Office of Industrial Technologies and the DOE Office of Energy Research. The presentation will discuss materials for body/chassis and power train, and will highlight the considerable synergy among the efforts. The bulk of the effort is on castings, sheet, and alloys with a smaller focus on metal matrix composites. Cost reduction and energy savings are the overriding themes of the programs.
Date: February 28, 1999
Creator: Carpenter, J.; Diamond, S.; Dillich, S.; Fitzsimmons, T.; Milliken, J. & Sklad, P.
Partner: UNT Libraries Government Documents Department

Final Report: Interactive Web Technologies for Dissemination of Scientific Graphics, September 2, 1998 - March 17, 1999

Description: An interactive software tool was developed to support the dissemination of scientific graphics. The technologies were developed both as a Java applet and stand-alone application and allow images to be disseminated as a data collection and an appearance script. Phase I efforts defined the model for the grahics tools. Software prototypes were constructed to test the utility of the graphics tool and refine the model.
Date: February 28, 1999
Creator: Stone, Craig
Partner: UNT Libraries Government Documents Department

Final Report: Latent Expression of Genetic Damage in Human Lung Cells

Description: This project was aimed at furthering understanding of the latent effects of ionizing radiation. The underlying premise was that such latent (i.e., delayed) effects stemmed from radiation-induced genetic instability. As model system to investigate certain aspects of genomic instability, they proposed to look at chromosomal instability involving quasi-targeted radiation-induced breakpoints in the vicinity of the HPRT gene in EJ30 human epithelial cells. Using whole chromosome painting of the X chromosome, the authors were able to show that about 15% of randomly selected 6-thioguanine resistant (6TG{prime}) mutants involved translocations in the terminal portion of Xq. Subsequent analysis, using human genomic YAC probes confirmed that all the translocations were either within (or near Xq26.1), the cytogenetic location of HPRT, whereas none were found elsewhere involving the X chromosome.
Date: February 28, 1999
Creator: Cornforth, Michael N.
Partner: UNT Libraries Government Documents Department

National Society of Black Physicists XXV Annual Day of Scientific Lectures and 21st Annual Meeting - NSBP '98: The Next Generation/12th Annual National Conference of Black Physics Students - NCPBS '98: Physics/Life in Motion

Description: The 12th Annual National Conference of Black Physics Students (NCBPS) was held jointly with the Annual Meeting of the National Society of Black Physicists (NSBP) March 4-8, 1998 in Lexington, Ky. The Proceedings consists of scientific talks and abstracts given by NSBP members and students attending the NCBPS meeting. One joint session of general scientific interest was held, with NCBPS students, NSBP members, and about 75 high school students from the state of Kentucky present. NCBPS session included ''How to get into Graduate School'', ''How to Survive in Graduate School'', and a Panel on ''Opportunities for Physics Graduates.'' The report by AIP: ''Survey of Participants of the 12th Annual NCBPS'' is included in the Proceedings.
Date: February 28, 1999
Creator: MacKellar, Alan (ed.)
Partner: UNT Libraries Government Documents Department