Transmission electron microscopy of oxide dispersion strengthened (ODS) molybdenum: effects of irradiation on material microstructure (open access)

Transmission electron microscopy of oxide dispersion strengthened (ODS) molybdenum: effects of irradiation on material microstructure

Oxide dispersion strengthened (ODS) molybdenum has been characterized using transmission electron microscopy (TEM) to determine the effects of irradiation on material microstructure. This work describes the results-to-date from TEM characterization of unirradiated and irradiated ODS molybdenum. The general microstructure of the unirradiated material consists of fine molybdenum grains (< 5 {micro}m average grain size) with numerous low angle boundaries and isolated dislocation networks. 'Ribbon'-like lanthanum oxides are aligned along the working direction of the product form and are frequently associated with grain boundaries, serving to inhibit grain boundary and dislocation movement. In addition to the 'ribbons', discrete lanthanum oxide particles have also been detected. After irradiation, the material is characterized by the presence of nonuniformly distributed large ({approx} 20 to 100 nm in diameter), multi-faceted voids, while the molybdenum grain size and oxide morphology appear to be unaffected by irradiation.
Date: March 3, 2003
Creator: Baranwal, R. and Burke, M.G.
System: The UNT Digital Library
Review of the margins for ASME code fatigue design curve - effects of surface roughness and material variability. (open access)

Review of the margins for ASME code fatigue design curve - effects of surface roughness and material variability.

The ASME Boiler and Pressure Vessel Code provides rules for the construction of nuclear power plant components. The Code specifies fatigue design curves for structural materials. However, the effects of light water reactor (LWR) coolant environments are not explicitly addressed by the Code design curves. Existing fatigue strain-vs.-life ({var_epsilon}-N) data illustrate potentially significant effects of LWR coolant environments on the fatigue resistance of pressure vessel and piping steels. This report provides an overview of the existing fatigue {var_epsilon}-N data for carbon and low-alloy steels and wrought and cast austenitic SSs to define the effects of key material, loading, and environmental parameters on the fatigue lives of the steels. Experimental data are presented on the effects of surface roughness on the fatigue life of these steels in air and LWR environments. Statistical models are presented for estimating the fatigue {var_epsilon}-N curves as a function of the material, loading, and environmental parameters. Two methods for incorporating environmental effects into the ASME Code fatigue evaluations are discussed. Data available in the literature have been reviewed to evaluate the conservatism in the existing ASME Code fatigue evaluations. A critical review of the margins for ASME Code fatigue design curves is presented.
Date: October 3, 2003
Creator: Chopra, O. K.; Shack, W. J. & Technology, Energy
System: The UNT Digital Library
UC Berkeley Seismic Guidelines, Appendix II: Ground Motion TimeHistories for the UC Berkeley Campus (open access)

UC Berkeley Seismic Guidelines, Appendix II: Ground Motion TimeHistories for the UC Berkeley Campus

Three sets of ten time histories each were developed to represent the ground motions for each of the three return periods. All of the time histories are provided as pairs of fault-normal and fault-parallel components. The ground motion time histories are provided in two forms: unmodified, and spectrally modified to match the probabilistic response spectra. The unmodified time histories can be scaled to match the probabilistic response spectra at a specified period, such as the first mode period of the structure being analyzed, while leaving the shape of the response spectrum unmodified. This approach preserves the particular characteristics of the individual time history, together with the peaks and troughs of its response spectrum. These individual characteristics are modified in the spectrally matched time histories, resulting in a suite of ten time histories (for a given return period) that all have the same response spectrum for a given component (fault normal or fault parallel) that follows the smooth shape of the probabilistic response spectrum.
Date: June 3, 2003
Creator: unknown
System: The UNT Digital Library
Results from the First {sup 249}Cf + {sup 48}Ca Experiment (open access)

Results from the First {sup 249}Cf + {sup 48}Ca Experiment

The present paper reports the results of an attempt aimed at the synthesis of element 118 in the reaction {sup 249}Cf({sup 48}Ca,3n){sup 294}118. The experiment was performed employing the Dubna Gas-filled Recoil Separator and the U400 heavy-ion cyclotron at FLNR, JINR, Dubna. In the course of a 2300-hour irradiation of an enriched {sup 249}Cf target (0.23 mg/cm{sup 2}) with a beam of 245-MeV {sup 48}Ca ions, we accumulated a total beam dose of 2.5 x 10{sup 19} ions. We detected two events that may be attributed to the formation and decay of nuclei with Z=118. For one event, we observed a decay chain of two correlated {alpha}-decays with corresponding energies and correlation times of E{sub {alpha}1} = 11.65 {+-} 0.06 MeV, t{sub {alpha}1} = 2.55 ms and E{sub {alpha}2} = 10.71 {+-} 0.17 MeV, t{sub {alpha}2} = 42.1 ms and, finally, a spontaneous fission with the sum of the kinetic energies of the fission fragments E{sub tot} = 207 MeV (TKE {approx} 230 MeV) and t{sub SF} = 0.52 s. In the second event chain, the recoil nucleus decayed into two fission fragments with E{sub tot} = 223 MeV (TKE {approx} 245 MeV) 3.16 ms later, without intervening {alpha} decays. …
Date: February 3, 2003
Creator: Oganessian, Y T; Utyonkov, V K; Lobanov, Y V; Abdullin, F S; Polyakov, A N; Shirokovsky, I V et al.
System: The UNT Digital Library
Ultrasonic Examination of Double-Shell Tank 241-AN-105 Examination Completed September 2002 (open access)

Ultrasonic Examination of Double-Shell Tank 241-AN-105 Examination Completed September 2002

COGEMA Engineering Corporation (COGEMA), under contract from CH2M Hill Hanford Group (CH2M Hill), has performed an ultrasonic examination of selected portions of Double-Shell Tank 241-AN-105. The purpose of this examination was to provide information that could be used to evaluate the integrity of the wall of the primary tank. The requirements for the ultrasonic examination of Tank 241-AN-105 were to detect, characterize, (idetify, size, and locate), and recod measurements made of any wall thinning, pitting, or cracks that might be present in the wall of the primary tank. Any measurements that exceed the requirements set forth in the Engineering Task Plan (ETP), RPP-8867, are reported to CH2M Hill and the Pacific Northwest National Laboratory (PNNL) for further evaluation. Under the contract with CH2M Hill, all data is to be recorded on disk and paper copies of all measurements are provided to PNNL for third-party evaluation. PNNL is responsible for preparing a reports(s) that describes the results of the COGEMA ultrasonic examinations.
Date: January 3, 2003
Creator: Pardini, Allan F. (BATTELLE (PACIFIC NW LAB)) & Posakony, Gerald J. (BATTELLE (PACIFIC NW LAB))
System: The UNT Digital Library
An Investigation to Resolve the Interaction Between Fuel Cell, Power Conditioning System and Application Loads (open access)

An Investigation to Resolve the Interaction Between Fuel Cell, Power Conditioning System and Application Loads

Solid-Oxide Fuel Cell (SOFC) stacks respond quickly to changes in load and exhibit high part- and full-load efficiencies due to its rapid electrochemistry. However, this is not true for the thermal, mechanical, and chemical balance-of-plant subsystem (BOPS), where load-following time constants are, typically, several orders of magnitude higher. This dichotomy diminishes the reliability and performance of the electrode with increasing demand of load. Because these unwanted phenomena are not well understood, the manufacturers of SOFC use conservative schemes (such as, delayed load-following to compensate for slow BOPS response or expensive inductor filtering) to control stack responses to load variations. This limits the applicability of SOFC systems for load-varying stationary and transportation applications from a cost standpoint. Thus, a need exists for the synthesis of component- and system-level models of SOFC power-conditioning systems and the development of methodologies for investigating the system-interaction issues (which reduce the lifetime and efficiency of a SOFC) and optimizing the responses of each subsystem, leading to optimal designs of power-conditioning electronics and optimal control strategies, which mitigate the electrical-feedback effects. Equally important are ''multiresolution'' finite-element modeling and simulation studies, which can predict the impact of changes in system-level variables (e.g., current ripple and load-transients) on the …
Date: November 3, 2003
Creator: Mazumder, Sudip K.; McKintyre, Chuck; Herbison, Dan; Nelson, Doug; Haynes, Comas; Spakovsky, Michael von et al.
System: The UNT Digital Library
Methods and Models of the Hanford Internal Dosimetry Program, PNNL-MA-860 (open access)

Methods and Models of the Hanford Internal Dosimetry Program, PNNL-MA-860

This manual describes the technical basis for the design of the routine radiobioassay monitoring program and assessments of internal dose. Its purpose is to provide a historical record of the methods, models, and assumptions used for internal dosimetry at Hanford, and serve as a technical reference for radiation protection and dosimetry staff.
Date: January 3, 2003
Creator: Carbaugh, Eugene H.; Bihl, Donald E. & Maclellan, Jay A.
System: The UNT Digital Library
IMPROVED CATALYSTS FOR HEAVY OIL UPGRADING BASED ON ZEOLITE Y NANOPARTICLES ENCAPSULATED IN STABLE NANOPOROUS HOSTS (open access)

IMPROVED CATALYSTS FOR HEAVY OIL UPGRADING BASED ON ZEOLITE Y NANOPARTICLES ENCAPSULATED IN STABLE NANOPOROUS HOSTS

The focus of this project is to improve the catalytic performance of zeolite Y for petroleum hydrocracking by synthesizing nanoparticles of the zeolite ({approx}20-25 nm) inside nanoporous silicate or aluminosilicate hosts. The encapsulated zeolite nanoparticles are expected to possess reduced diffusional path lengths, hence hydrocarbon substrates will diffuse in, are converted and the products quickly diffused out. This is expected to prevent over-reaction and the blocking of the zeolite pores and active sites will be minimized. In this phase of the project, procedures for the synthesis of ordered nanoporous silica, such as SBA-15, using block copolymers and nonionic surfactant were successful reproduced. Expansion of the pores sizes of the nanoporous silica using trimethylbenzene is suggested based on shift in the major X-Ray Diffraction peak in the products to lower 2 angles compared with the parent SBA-15 material. The synthesis of ordered nanoporous materials with aluminum incorporated in the predominantly silicate framework was attempted but is not yet successful, and the procedures needs will be repeated and modified as necessary. Nanoparticles of zeolite Y of particle sizes in the range 40 nm to 120 nm were synthesized in the presence of TMAOH as the particle size controlling additive.
Date: September 3, 2003
Creator: Ingram, Conrad
System: The UNT Digital Library
REPORT on the TRUCK BRAKE LINING WORKSHOP and FLEET OPERATORS' SURVEY (open access)

REPORT on the TRUCK BRAKE LINING WORKSHOP and FLEET OPERATORS' SURVEY

The report summarizes what transpired during brake linings-related workshop held at the Fall 2003 meeting of the Technology and Maintenance Council (TMC) in Charlotte, NC. The title of the workshop was ''Developing a Useful Friction Material Rating System''. It was organized by a team consisting of Peter Blau (Oak Ridge National Laboratory), Jim Britell (National Highway Traffic Safety Administration), and Jim Lawrence (Motor and Equipment Manufacturers Association). The workshop was held under the auspices of TMC Task Force S6 (Chassis), chaired by Joseph Stianche (Sanderson Farms, Inc.). Six invited speakers during the morning session provided varied perspectives on testing and rating aftermarket automotive and truck brake linings. They were: James R. Clark, Chief Engineer, Foundation Brakes and Wheel Equipment, Dana Corporation, Spicer Heavy Axle and Brake Division; Charles W. Greening, Jr, President, Greening Test Labs; Tim Duncan, General Manager, Link Testing Services;Dennis J. McNichol, President, Dennis NationaLease; Jim Fajerski, Business Manager, OE Sales and Applications Engineering, Federal Mogul Corporation; and Peter J. Blau, Senior Materials Development Engineer, Oak Ridge National Laboratory. The afternoon break-out sessions addressed nine questions concerning such issues as: ''Should the federal government regulate aftermarket lining quality?''; ''How many operators use RP 628, and if so, what's …
Date: February 3, 2003
Creator: Blau, P.J.
System: The UNT Digital Library
Revised Unfilling Procedure for Solid Lithium Lenses (open access)

Revised Unfilling Procedure for Solid Lithium Lenses

A procedure for unfilling used lithium lenses to has been described in Pbar Note 664. To date, the procedure has been used to disassemble lenses 20, 21, 17, 18, and 16. As a result of this work, some parts of the original procedure were found to be time consuming and ineffective. Modifications to the original procedure have been made to streamline the process and are discussed in this note. The revised procedure is included in this note.
Date: June 3, 2003
Creator: Leveling, A.
System: The UNT Digital Library
UC Berkeley Seismic Guidelines, Appendix II: Ground Motion Time Histories for the UC Berkeley Campus (open access)

UC Berkeley Seismic Guidelines, Appendix II: Ground Motion Time Histories for the UC Berkeley Campus

Three sets of ten time histories each were developed to represent the ground motions for each of the three return periods. All of the time histories are provided as pairs of fault-normal and fault-parallel components. The ground motion time histories are provided in two forms: unmodified, and spectrally modified to match the probabilistic response spectra. The unmodified time histories can be scaled to match the probabilistic response spectra at a specified period, such as the first mode period of the structure being analyzed, while leaving the shape of the response spectrum unmodified. This approach preserves the particular characteristics of the individual time history, together with the peaks and troughs of its response spectrum. These individual characteristics are modified in the spectrally matched time histories, resulting in a suite of ten time histories (for a given return period) that all have the same response spectrum for a given component (fault normal or fault parallel) that follows the smooth shape of the probabilistic response spectrum.
Date: June 3, 2003
Creator: Authors, Various
System: The UNT Digital Library
Characterize Framework for Igneous Activity at Yucca Mountain, Nevada (open access)

Characterize Framework for Igneous Activity at Yucca Mountain, Nevada

None
Date: November 3, 2003
Creator: Perry, F.; Youngs, R. & Vogt, T.
System: The UNT Digital Library
2002 status report: Savings estimates for the ENERGY STAR(R) voluntary labeling program (open access)

2002 status report: Savings estimates for the ENERGY STAR(R) voluntary labeling program

ENERGY STAR [registered trademark] is a voluntary labeling program designed to identify and promote energy-efficient products, buildings and practices. Operated jointly by the Environmental Protection Agency (EPA) and the U.S. Department of Energy (DOE), ENERGY STAR labels exist for more than thirty products, spanning office equipment, residential heating and cooling equipment, commercial and residential lighting, home electronics, and major appliances. This report presents savings estimates for a subset of ENERGY STAR program activities, focused primarily on labeled products. We present estimates of the energy, dollar and carbon savings achieved by the program in the year 2001, what we expect in 2002, and provide savings forecasts for two market penetration scenarios for the period 2002 to 2020. The target market penetration forecast represents our best estimate of future ENERGY STAR savings. It is based on realistic market penetration goals for each of the products. We also provide a forecast under the assumption of 100 percent market penetration; that is, we assume that all purchasers buy ENERGY STAR-compliant products instead of standard efficiency products throughout the analysis period.
Date: March 3, 2003
Creator: Webber, Carrie A.; Brown, Richard E.; McWhinney, Marla & Koomey, Jonathan
System: The UNT Digital Library
DOE Grant for Travel - ISMB 2002, Edmont, Canada. (open access)

DOE Grant for Travel - ISMB 2002, Edmont, Canada.

The Intelligent Systems for Molecular Biology (ISMB) conference is the oldest and largest conference that specifically addresses bioinformatics and computational biology, i.e. interdisciplinary research that falls between computer science and biology, ISMB is distinguished from many other conferences in computational biology or artificial intelligence by an insistence that the researchers work with real molecular biology data, not theoretical examples; and from many other biological conferences by providing a forum for technical advances as they occur, which otherwise may be shunned until a firm experimental result is published. The resulting intellectual richness and cross-disciplinary diversity provides an important opportunity for both students and senior researchers. ISMB has become the premier conference series in this field with refereed, published proceedings, establishing an infrastructure to promote the growing body of research. ISMB comprises five main types of presentations: tutorials, plenary presentations, poster presentations, topically focused satellite meetings and software demonstrations. These tutorials and fellows contribute to the development of human resources by allowing students and post-doctoral fellows to reach a state-of-the-art level rapidly, and to begin making contributions to the field. At ISMB 2002, 15 tutorials were held, 50 papers were presented, 498 posters were presented, 6 special interest group meetings here held, …
Date: August 3, 2003
Creator: Rost, Burkhard
System: The UNT Digital Library
A Polymer Membrane Containing Fe0 as a Contaminant Barrier (open access)

A Polymer Membrane Containing Fe0 as a Contaminant Barrier

A polyvinyl alcohol (PVA) membrane containing iron (Fe0) particles was developed and tested as a model barrier for contaminant containment. Carbon tetrachloride, copper (Cu2+), nitrobenzene, 4-nitroacetophenone, and chromate (CrO4 2-) were selected as model contaminants. Compared with a pure PVA membrane, the Fe0/PVA membrane can increase the breakthrough lag time for Cu2+ and carbon tetrachloride by more than 100 fold. The increase in the lag time was smaller for nitrobenzene and 4-nitroacetophenone which stoichiometrically require more iron and for which the PVA membrane has a higher permeability. The effect of Fe0 was even smaller for CrO4 2- because of its slow reaction. Forty-five percent of the iron, based on the content in the dry membrane prior to hydration, was consumed by reaction with Cu2+ and 19% by reaction with carbon tetrachloride. Similarly, 25%, 17%, and 6% of the iron was consumed by nitrobenzene, 4-nitroacetophenone, and CrO4 2-, respectively. These percentages approximately double when the loss of iron during membrane hydration is considered. The permeability of the Fe0/PVA membrane after breakthrough was within a factor of three for that of pure PVA, consistent with theory. These results suggest that polymer membranes with embedded Fe0 have potential as practical contaminant barriers.
Date: November 3, 2003
Creator: Shimotori, Tsutomu; Nuxoll, Eric E.; Cussler, Edward L. & Arnold, William A.
System: The UNT Digital Library
MEASUREMENT OF FRICTIONAL PRESSURE DIFFERENTIALS DURING A VENTILATION SURVEY (open access)

MEASUREMENT OF FRICTIONAL PRESSURE DIFFERENTIALS DURING A VENTILATION SURVEY

During the course of a ventilation survey, both airflow quantity and frictional pressure losses are measured and quantified. The measurement of airflow has been extensively studied as the vast majority of ventilation standards/regulations are tied to airflow quantity or velocity. However, during the conduct of a ventilation survey, measurement of airflow only represents half of the necessary parameters required to directly calculate the airway resistance. The measurement of frictional pressure loss is an often misunderstood and misapplied part of the ventilation survey. This paper compares the two basic methods of frictional pressure drop measurements; the barometer and the gauge and tube. Personal experiences with each method will be detailed along with the authors' opinions regarding the applicability and conditions favoring each method.
Date: November 3, 2003
Creator: B.S. Prosser, PE & I.M. Loomis, PE, PhD
System: The UNT Digital Library
Visual Communications for Heterogeneous Networks/Visually Optimized Scalable Image Compression. Final Report for September 1, 1995 - February 28, 2002 (open access)

Visual Communications for Heterogeneous Networks/Visually Optimized Scalable Image Compression. Final Report for September 1, 1995 - February 28, 2002

The authors developed image and video compression algorithms that provide scalability, reconstructibility, and network adaptivity, and developed compression and quantization strategies that are visually optimal at all bit rates. The goal of this research is to enable reliable ''universal access'' to visual communications over the National Information Infrastructure (NII). All users, regardless of their individual network connection bandwidths, qualities-of-service, or terminal capabilities, should have the ability to access still images, video clips, and multimedia information services, and to use interactive visual communications services. To do so requires special capabilities for image and video compression algorithms: scalability, reconstructibility, and network adaptivity. Scalability allows an information service to provide visual information at many rates, without requiring additional compression or storage after the stream has been compressed the first time. Reconstructibility allows reliable visual communications over an imperfect network. Network adaptivity permits real-time modification of compression parameters to adjust to changing network conditions. Furthermore, to optimize the efficiency of the compression algorithms, they should be visually optimal, where each bit expended reduces the visual distortion. Visual optimality is achieved through first extensive experimentation to quantify human sensitivity to supra-threshold compression artifacts and then incorporation of these experimental results into quantization strategies and compression …
Date: June 3, 2003
Creator: Hemami, S. S.
System: The UNT Digital Library
SEARCH FOR THE RARE KAON DECAY K{sup +} {yields} {pi}{sup +} {nu}{bar {nu}} (open access)

SEARCH FOR THE RARE KAON DECAY K{sup +} {yields} {pi}{sup +} {nu}{bar {nu}}

This thesis describes the search for the rare decay K{sup +} {yields} {pi}{sup +} {nu}{bar {nu}} in the pion momentum region 140 MeV/c {le} P{sub {pi}{sup +}} {le} 195 MeV/c. This is a Flavor Changing Neutral Current (FCNC) decay which is forbidden to the first order in the Standard Model (SM) by the GIM mechanism. However, this decay mode is allowed in the second order by two Z-Penguin and one box diagram and is expected to have a branching ratio of (0.72 {+-} 0.21) x 10{sup -10}. This decay mode is sensitive to the coupling of top to down quark and therefore a measurement of the branching ratio for this decay mode provides a measurement of the Cabibbo-Kobayashi-Maskawa matrix element V{sub td}. The recent observation of two events in the pion momentum region 211 MeV/c {le} P{sup {pi}{sup +}} {le} 229 MeV/c estimates a branching ratio of 1.57{sub -0.82}{sup +1.75} x 10{sup -10} for the same decay mode. We have extended the search for this decay to the lower pion momentum region. Data collected by the Experiment E787 at Brookhaven National Laboratory during the 1996 and 1997 run were analyzed in this thesis.
Date: May 3, 2003
Creator: BHUYAN,B.
System: The UNT Digital Library
MCNPX Model/Table Comparison (open access)

MCNPX Model/Table Comparison

MCNPX is a Monte Carlo N-Particle radiation transport code extending the capabilities of MCNP4C. As with MCNP, MCNPX uses nuclear data tables to transport neutrons, photons, and electrons. Unlike MCNP, MCNPX also uses (1) nuclear data tables to transport protons; (2) physics models to transport 30 additional particle types (deuterons, tritons, alphas, pions, muons, etc.); and (3) physics models to transport neutrons and protons when no tabular data are available or when the data are above the energy range (20 to 150 MeV) where the data tables end. MCNPX can mix and match data tables and physics models throughout a problem. For example, MCNPX can model neutron transport in a bismuth germinate (BGO) particle detector by using data tables for bismuth and oxygen and using physics models for germanium. Also, MCNPX can model neutron transport in UO{sub 2}, making the best use of physics models and data tables: below 20 MeV, data tables are used; above 150 MeV, physics models are used; between 20 and 150 MeV, data tables are used for oxygen and models are used for uranium. The mix-and-match capability became available with MCNPX2.5.b (November 2002). For the first time, we present here comparisons that calculate radiation transport …
Date: March 3, 2003
Creator: Hendricks, J.S.
System: The UNT Digital Library
Final Report: Pilot-Scale Cross-Flow Ultrafiltration Test Using a Hanford Site Tank 241-AN-102 Waste Simulant (open access)

Final Report: Pilot-Scale Cross-Flow Ultrafiltration Test Using a Hanford Site Tank 241-AN-102 Waste Simulant

Bechtel National l, Inc. (BNI) has been contracted to design a Waste Treatment and Immobilization Plant (WTP) to stabilize liquid radioactive waste that is stored at the Hanford Site as part of the River Protection Project (RPP). Because of its experience with radioactive waste stabilization, the Savannah River Technology Center (SRTC) is working with BNI to help design and test certain parts of the waste treatment facility. One part of the process is the separation of radioactive solids from the liquid wastes by cross- flow ultrafiltration. This task tested a cross- flow filter, prototypic in porosity, length and diameter, with a simulated radioactive waste, made to prototypically represent the chemical and physical characteristics of a Hanford waste in tank 241-AN-102 (AN-102) and precipitated under prototypic conditions. This report discusses the results of cross- flow filter operation in a pilot-scale experimental facility. This filter technology was evaluated for its inclusion in the pretreatment section of the nuclear waste stabilization plant being designed by Bechtel National, Inc. The waste treatment plant will be built at the U.S. Department of Energy's Hanford Site as part of the River Protection Project.
Date: October 3, 2003
Creator: Duignan, M.R.
System: The UNT Digital Library
Theoretical modeling of the kinetics of barrierless reactions. Final report: DE-FG02-98ER14902 (open access)

Theoretical modeling of the kinetics of barrierless reactions. Final report: DE-FG02-98ER14902

Recent progress is reported on a research program aimed at developing and applying sophisticated transition state theory-based models for the kinetics of barrierless reactions of importance in combustion. Various applications involving the coupling of the variable reaction coordinate (VRC) transition state theory (TST) methodology with ab initio quantum chemical evaluations and/or master equation simulations were provided. Reactions studied included the C{sub 3}H{sub 3} + H and C{sub 3}H{sub 5} + H addition reactions, C{sub 2}H{sub 3} + C{sub 2}H{sub 2} and C{sub 2}H{sub 5} + O{sub 2} reactions, and the unimolecular dissociation of ketene.
Date: January 3, 2003
Creator: Klippenstein, Stephen J.
System: The UNT Digital Library
An Evaluation of Aquifer Source Node Location Alternatives for E-Area Slit Trench Performance Assessment (open access)

An Evaluation of Aquifer Source Node Location Alternatives for E-Area Slit Trench Performance Assessment

The present special study proposes an improvement to the current method for selecting aquifer source node locations that is a more realistic representation of actual subsurface conditions. This improved concept for defining aquifer source node locations has been identified through an objective evaluation of several alternatives.
Date: June 3, 2003
Creator: Flach, G. P.
System: The UNT Digital Library
Tank 50H Tetraphenylborate Destruction Results (open access)

Tank 50H Tetraphenylborate Destruction Results

We conducted several scoping tests with both Tank 50H surrogate materials (KTPB and phenol) as well as with actual Tank 50H solids. These tests examined whether we could destroy the tetraphenylborate in the surrogates or actual Tank 50H material either by use of Fenton's Reagent or by hydrolysis (in Tank 50H conditions at a maximum temperature of 50 degrees C) under a range of conditions. The results of these tests showed that destruction of the solids occurred only under a minority of conditions. (1)Using Fenton's Reagent and KTPB as the Tank 50H surrogate, no reaction occurred at pH ranges greater than 9. (2)Using Fenton's Reagent and phenol as the Tank 50H surrogate, no reaction occurred at a pH of 14. (3)Using Fenton's Reagent and actual Tank 50H slurry, a reaction occurred at a pH of 9.5 in the presence of ECC additives. (4)Using Fenton's Reagent and actual Tank 50H slurry, after a thirty three day period, all attempts at hydrolysis (at pH 14) were too slow to be viable. This happened even in the case of higher temperature (50 degrees C) and added (100 ppm) copper. Tank 50H is scheduled to return to HLW Tank Farm service with capabilities of …
Date: October 3, 2003
Creator: Peters, T.B.
System: The UNT Digital Library
The Kinetics of Dissociations of Aluminum - Oxygen Bonds in Aqueous Complexes - An NMR Study (open access)

The Kinetics of Dissociations of Aluminum - Oxygen Bonds in Aqueous Complexes - An NMR Study

OAK B262 The Kinetics of Dissociations of Aluminum--Oxygen Bonds in Aqueous Complexes--An NMR Study. In this project we determined rates and mechanisms of Al(III)-O bond rupture at mineral surfaces and in dissolved aluminum complexes. We then compared the experimental results to simulations in an attempt to predict rate coefficients. Most of the low-temperature reactions that are geochemically important involve a bonded atom or molecule that is replaced with another. We probe these reactions at the most fundamental level in order to establish a model to predict rates for the wide range of reactions that cannot be experimentally studied. The chemistry of small aluminum cluster (Figure) provides a window into the hydrolytic processes that control rates of mineral formation and the transformation of adsorbates into extended structures. The molecule shown below as an example exposes several types of oxygens to the bulk solution including seven structurally distinct sets of bridging hydroxyls. This molecule is a rich model for the aqueous interface of aluminum (hydr)oxide minerals, since it approaches colloidal dimensions in size, yet is a dissolved complex with +18 charge. We have conducted both {sup 17}O- {sup 27}Al- and {sup 19}F-NMR experiments to identify the reactive sites and to determine the …
Date: September 3, 2003
Creator: Casey, Dr. William
System: The UNT Digital Library