Atomic defects and diffusion in metals (open access)

Atomic defects and diffusion in metals

The tracer self-diffusion data for fcc and refractory bcc metals are briefly reviewed with respect to (i) the available monovacancy formation and migration properties and (ii) the high-temperature diffusion enhancement above that expected for mass transport via atomic exchange with monovacancies. While the atomic-defect mechanism for low-temperature self-diffusion can be reliably attributed to monovacancies, the mechanisms responsible for high-temperature mass transport are not so easily defined at this time; both divacancies and interstitials must be seriously considered. Possibilities for improving our understanding in this area are discussed. 68 references, 7 figures.
Date: November 1, 1981
Creator: Siegel, R. W.
Object Type: Report
System: The UNT Digital Library
Mechanism and kinetics of radiation-induced segregation in Ni-Si alloys (open access)

Mechanism and kinetics of radiation-induced segregation in Ni-Si alloys

Rutherford-backscattering and Auger chemical-depth-profiling measurements show that films of the ..gamma..'-Ni/sub 3/Si phase produced on the ion-bombarded surfaces of Ni-Si alloys obey simple parabolic growth kinetics. At low temperatures the film growth-rate constant exhibits Arrhenius behavior and varies with the fourth root of the dose rate. The apparent activation energy in this low-temperature region is approx. 0.3 eV. At high temperatures the growth constant is independent of the dose rate. The results are consistent with a diffusion-controlled growth model, which assumes Si atoms migrate in the form of a fast-diffusing Si-interstitial complex.
Date: November 1, 1981
Creator: Okamoto, P. R.; Rehn, L. E.; Averback, R. S.; Robrock, K. H. & Wiedersich, H.
Object Type: Article
System: The UNT Digital Library
Electronic structure and formation energy of a vacancy in aluminum (open access)

Electronic structure and formation energy of a vacancy in aluminum

The electronic structure of a vacancy in Al was calculated self-consistently using norm-conserving ionic pseudopotentials obtained from ab initio atomic calculations. A 27-atom-site supercell containing 1 vacancy and 26 atoms was used to simulate the environment of the vacancy. A vacancy formation energy of 1.5 eV was also calculated (cf. the experimental value of 0.66 eV). The effects of the supercell and the nature of the ionic potential on the resulting electronic structure and formation energy are discussed. Results for the electronic structure of a divacancy are also presented. 3 figures.
Date: November 1, 1981
Creator: Chakraborty, B. & Siegel, R. W.
Object Type: Article
System: The UNT Digital Library
Segregation in irradiated titanium alloys. [Ion irradiation (2. 1 MeV Ar/sup +/) of Ti-6Al-4V, Ti-8Al-1V-Mo, Ti-3V and Ti-8. 7 Al] (open access)

Segregation in irradiated titanium alloys. [Ion irradiation (2. 1 MeV Ar/sup +/) of Ti-6Al-4V, Ti-8Al-1V-Mo, Ti-3V and Ti-8. 7 Al]

Radiation-induced segregation of V, Al and Mo in ..cap alpha..-phase titanium alloys was investigated. Ion irradiation (2.1-MeV Ar/sup +/) at 650/sup 0/C was used to simulate elevated-temperature neutron irradiation effects. Solute segregation in the near-surface regions of irradiated Ti-6Al-4V, Ti-8Al-1V-1Mo, Ti-3V and Ti-8.71Al was measured with an Auger depth profiling technique. The depth profiles showed evidence of radiation-induced V, Mo and Al segregation toward sample surfaces. This is in accord with a solute size effect. 6 figures.
Date: November 1, 1981
Creator: Wang, Z.; Ayrault, G. & Wiedersich, H.
Object Type: Report
System: The UNT Digital Library
Quantitative comparison of the void distribution in a. beta. '-phase Ni-Al-In alloy using x-ray small-angle scattering and transmission-electron microscopy. [Ni-51. 2 at. % Al-2. 6 at. % In] (open access)

Quantitative comparison of the void distribution in a. beta. '-phase Ni-Al-In alloy using x-ray small-angle scattering and transmission-electron microscopy. [Ni-51. 2 at. % Al-2. 6 at. % In]

Small-angle scattering is a rather mature discipline which can yield valuable information on the size, amount, and distribution of inhomogeneities encountered in materials-science research. Methods have been publisheed which permit one to extend the standard analysis of data from a small-angle-scattering experiment to include determination of the distribution of particle sizes. This extended analysis has been carried out for voids in a ..beta..'-phase Ni-Al-In alloy, and, in order to assess the reliability of the procedure, the identical void distribution as been characterized by transmission-electron microscopy. A quantitative comparison is made of the results from thses two independent experiments, and the general performance of the Brill-Schmidt method for particle-size determinations is discussed. 6 figures, 1 table.
Date: November 1, 1981
Creator: Epperson, J. E.; Loomis, B. A. & Lin, J. S.
Object Type: Article
System: The UNT Digital Library
Ion-bombardment-induced subsurface composition modifications in alloys at elevated temperatures. [Cu - 40 at. % Ni] (open access)

Ion-bombardment-induced subsurface composition modifications in alloys at elevated temperatures. [Cu - 40 at. % Ni]

Modifications of subsurface alloy composition during high-temperature sputtering were studied using a comprehensive kinetic model that includes Gibbsian adsorption, preferential sputtering, displacement mixing, radiation-enhanced diffusion, and radiation-induced segregation. Numerical solutions were obtained for a Cu-40 at. % Ni alloy under 5-keV Ar/sup +/ ion bombardment as functions of time and temperature. The model predictions are in good qualitative agreement with recent experimental measurements.
Date: November 1, 1981
Creator: Lam, N.Q. & Wiedersich, H.
Object Type: Article
System: The UNT Digital Library
Basalt Waste Isolation Project. Quarterly report, July 1, 1981-September 30, 1981 (open access)

Basalt Waste Isolation Project. Quarterly report, July 1, 1981-September 30, 1981

This document reports progress made in the Basalt Waste Isolation Project during the fourth quarter of fiscal year 1981. Efforts are described for the following programs of the project work breakdown structure: systems, waste package, site, repository, regulatory and institutional, test facilities, and in-situ test facilities.
Date: November 1, 1981
Creator: Deju, R.A.
Object Type: Report
System: The UNT Digital Library
PV-cell data-reduction computer program (draft). [PV-TAP, PVDR] (open access)

PV-cell data-reduction computer program (draft). [PV-TAP, PVDR]

The details are presented of a computer program to unfold current versus voltage (IV) data from a photovoltaic cell or module. IV data from both forward and reverse bias is used to calculate parameters such as series resistance, saturation current, shunt resistance, and junction emission constant. Standard deviations of calculated parameters are listed, and a plot of a calculated IV curve overlaying the empirical input data is produced.
Date: November 1, 1981
Creator: Lambarski, T.J.
Object Type: Report
System: The UNT Digital Library
Detector materials: germanium and silicon (open access)

Detector materials: germanium and silicon

This article is a summary of a short course lecture given in conjunction with the 1981 Nuclear Science Symposium. The basic physical properties of elemental semiconductors are reviewed. The interaction of energetic radiation with matter is discussed in order to develop a feeling for the appropriate semiconductor detector dimensions. The extremely low net dopant concentrations which are required are derived directly from the detector dimensions. A survey of the more recent techniques which have been developed for the analysis of detector grade semiconductor single crystals is presented.
Date: November 1, 1981
Creator: Haller, E.E.
Object Type: Article
System: The UNT Digital Library
Energy conservation in citrus processing. Final project report (open access)

Energy conservation in citrus processing. Final project report

Alternative energy conserving systems for use in citrus processing plants were synthesized and evaluated in terms of energy savings and economic return. The energy intensive operations that are carried out in citrus processing plants include conveying and extraction, concentration, peel drying, refrigeration, and pasteurization. The alternative energy conserving systems are synthesized from components and subsystems that are arranged to make use of energy cascading and thermodynamic regeneration to reduce the overall energy usage. System requirements such as air pollution rules and plant processing load cycles, a characterization of major operations, description of alternative system concepts, and the evaluation of alternative systems in terms of economic parameters and energy usage are identified.
Date: November 1, 1981
Creator: Leo, M. A.; Lari, R. I.; Moore, N. R.; Broussard, M. R. & Gyamfi, M.
Object Type: Report
System: The UNT Digital Library
Theoretical relationships between creep and swelling by point defect absorption during irradiation (open access)

Theoretical relationships between creep and swelling by point defect absorption during irradiation

Relationships between irradiation creep and swelling implicit in the theories of these processes are derived. Four mechanisms of irradiation creep are treated. These are the climb-only process of preferred point defect absorption on dislocations; the climb and glide processes resulting from cumulative absorption of defects at dislocations, i.e., preferred absorption glide and swelling-driven creep; and the recently developed climb and glide process enabled by point defect concentration fluctuations resulting from cascades. The results are expressed both as differential equations for creep rate in terms of swelling rate and as integrated forms giving creep strain in terms of swelling for stabilized microstructures.
Date: November 1, 1981
Creator: Mansur, L.K. & Coghlan, W.A.
Object Type: Article
System: The UNT Digital Library
Uranium hydrogeochemical and stream sediment reconnaissance of the Bradfield Canal NTS quadrangle, Alaska. National Uranium Resource Evaluation (open access)

Uranium hydrogeochemical and stream sediment reconnaissance of the Bradfield Canal NTS quadrangle, Alaska. National Uranium Resource Evaluation

This report presents results of a Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) of the Bradfield Canal NTMS quadrangle, Alaska. In addition to this abbreviaed data release, more complete data are available to the public in machine-readable form. These machine-readable data, as well as quarterly or semiannual program progress reports containing further information on the HSSR program in general, or on the Los Alamos National Laboratory (LANL) portion of the program in particular, are available from DOE's Technical Library at its Grand Junction Area Office. Presented in this data release are location data, field analyses, and laboratory analyses of several different sample media. For the sake of brevity, many field site observations have not been included in this volume; these data are, however, available on the magnetic tape. Appendices A and B describe the sample media and summarize the analytical results for each medium. The data have been subdivided by one of the Los Alamos National Laboratory sorting programs of Zinkl and others (1981a) into groups of stream-sediment and lake-sediment samples. For each group which contains a sufficient number of observations, statistical tables, tables of raw data, and 1:1,000,000 scale maps of pertinent elements have been included in this report. Also …
Date: November 1, 1981
Creator: Shettel, D. L., Jr.; Langfeldt, S. L.; Hardy, L. C.; D'Andrea, R. F., Jr.; Zinkl, R. J.; Hensley, W. K. et al.
Object Type: Report
System: The UNT Digital Library
Potential geothermal energy applications for Idaho Elks Rehabilitation Hospital (open access)

Potential geothermal energy applications for Idaho Elks Rehabilitation Hospital

Several potential applications of geothermal energy for the Idaho Elks Rehabilitation Hospital are outlined. A brief background on the resource and distribution system, is provided; which hospital heating systems should be considered for potential geothermal retrofit is discussed; and technical and economic feasibility are addressed.
Date: November 1, 1981
Creator: Austin, John C.
Object Type: Report
System: The UNT Digital Library
Raft River geoscience case study (open access)

Raft River geoscience case study

The Raft River Geothermal Site has been evaluated over the past eight years by the United States Geological Survey and the Idaho National Engineering Laboratory as a moderate-temperature geothermal resource. The geoscience data gathered in the drilling and testing of seven geothermal wells suggest that the Raft River thermal reservoir is: (a) produced from fractures found at the contact metamorphic zone, apparently the base of detached normal faulting from the Bridge and Horse Well Fault zones of the Jim Sage Mountains; (b) anisotropic, with the major axis of hydraulic conductivity coincident to the Bridge Fault Zone; (c) hydraulically connected to the shallow thermal fluid of the Crook and BLM wells based upon both geochemistry and pressure response; (d) controlled by a mixture of diluted meteoric water recharging from the northwest and a saline sodium chloride water entering from the southwest. Although the hydrogeologic environment of the Raft River geothermal area is very complex and unique, it is typical of many Basin and Range systems.
Date: November 1, 1981
Creator: Dolenc, M. R.; Hull, L. C.; Mizell, S. A.; Russell, B. F.; Skiba, P. A.; Strawn, J. A. et al.
Object Type: Report
System: The UNT Digital Library
Geothermal source potential and utilization for methane generation and alcohol production (open access)

Geothermal source potential and utilization for methane generation and alcohol production

A study was conducted to assess the technical and economic feasibility of integrating a geothermally heated anaerobic digester with a fuel alcohol plant and cattle feedlot. Thin stillage produced from the alcohol production process and manure collected from the cattle feedlot would be digested in anaerobic digesters to produce biogas, a mixture of methane and carbon dioxide, and residue. The energy requirements to maintain proper digester temperatures would be provided by geothermal water. The biogas produced in the digesters would be burned in a boiler to produce low-pressure steam which would be used in the alcohol production process. The alcohol plant would be sized so that the distiller's grains byproduct resulting from the alcohol production would be adequate to supply the daily cattle feed requirements. A portion of the digester residue would substitute for alfalfa hay in the cattle feedlot ration. The major design criterion for the integrated facilty was the production of adequate distiller's grain to supply the daily requirements of 1700 head of cattle. It was determined that, for a ration of 7 pounds of distiller's grain per head per day, a 1 million gpy alcohol facility would be required. An order-of-magnitude cost estimate was prepared for the …
Date: November 1, 1981
Creator: Austin, J.C.
Object Type: Report
System: The UNT Digital Library
Feasibility of vitrifying EPICOR II organic resins (open access)

Feasibility of vitrifying EPICOR II organic resins

Two laboratory-scale runs have recently been completed to test the feasibility of a single-step incineration/vitrification process for Three Mile Island EPICOR II resins. The process utilizes vitrification equipment, specifically a 15-cm-dia in-can melter, and a specially designed feed technique. Two process tests, each conducted with 1.2 kg of EPICOR II resins loaded with nonradioactive cesium and strontium, showed excellent operational characteristics. Less than 0.8 wt% of the resins were entrained with the gaseous effluents in the second test. Cesium and strontium losses were controlled to 0.71 wt% and less. In addition, all the carbonaceous resins were converted completely to CO/sub 2/ with no detectable CO. Future activities are being directed to longer-term tests in laboratory-scale equipment to determine attainable volume reduction, process rates, and material conformance to processing conditions.
Date: November 1, 1981
Creator: Buelt, J.L.
Object Type: Report
System: The UNT Digital Library
Overview of energy-conservation research opportunities: executive summary (open access)

Overview of energy-conservation research opportunities: executive summary

A study of research opportunities that are important to developing advanced technologies for efficient energy use is presented. The study's purpose is to describe a wide array of attractive technical areas from which specific research and development programs could be implemented. Research areas are presented for potential application in each of the major energy end-use sectors. The analysis employs a systematic process for both identifying and screening candidate energy conservation research areas. The study team was comprehensive in its review of aggregate energy consumption and employed explicit criteria to evaluate the technology research areas.
Date: November 1, 1981
Creator: Hopp, W. J.; Hauser, S. G.; Hane, G. J.; Gurwell, W. E.; Bird, S. P.; Cliff, W. C. et al.
Object Type: Report
System: The UNT Digital Library
Pressure measurements in magnetic-fusion devices (open access)

Pressure measurements in magnetic-fusion devices

Accurate pressure measurements are important in magnetic fusion devices for: (1) plasma diagnostic measurements of particle balance and ion temperature; (2) discharge cleaning optimization; (3) vacuum system performance; and (4) tritium accountability. This paper reviews the application, required accuracy, and suitable instrumentation for these measurements. Demonstrated uses of ionization-type and capacitance-diaphragm gauges for various pressure and gas-flow measurements in tokamaks are presented, with specific reference to the effects of magnetic fields on gauge performance and the problems associated with gauge calibration.
Date: November 1, 1981
Creator: Dylla, H.F.
Object Type: Article
System: The UNT Digital Library
User's guide to the MESOI diffusion model and to the utility programs UPDATE and LOGRVU (open access)

User's guide to the MESOI diffusion model and to the utility programs UPDATE and LOGRVU

MESOI is an interactive, Lagrangian puff trajectory diffusion model. The model is documented separately (Ramsdell and Athey, 1981); this report is intended to provide MESOI users with the information needed to successfully conduct model simulations. The user is also provided with guidance in the use of the data file maintenance and review programs; UPDATE and LOGRVU. Complete examples are given for the operaton of all three programs and an appendix documents UPDATE and LOGRVU.
Date: November 1, 1981
Creator: Athey, G. F.; Allwine, K. J. & Ramsdell, J. V.
Object Type: Report
System: The UNT Digital Library
Need for desiccant in containers exposed to atmospheric conditions for long periods of time (open access)

Need for desiccant in containers exposed to atmospheric conditions for long periods of time

Current component and system designs are required to perform satisfactorily up to 25 years. A maximum leak rate of 1 x 10/sup -6/ cc(STP) helium/sec-atm is a frequent requirement for component containers. Calculations show that undesiccated component containers continuously exposed to 50% relative humidity at 20/sup 0/C and having an internal free volume of less than 300 cc and the above leak rate will allow the internal dew point to rise enough for potential liquid condensation in less than four years. For the same vapor pressure differential, the moisture permeation rate through one linear inch of silicone o-ring is 750 times as fast as moisture enters a welded container whose leak rate is 1 x 10/sup -6/ cc(STP) helium/sec-atm. For ethylene propylene o-ring material this ratio is about 13. These values correspond to the ratios of the quantities of desiccant required to maintain an acceptable dew point temperature when the moisture capacity of the free volume is not included. Charts are provided for estimating the amount of desiccant required for helium leak tested containers and for containers sealed with elastomeric o-rings.
Date: November 1, 1981
Creator: Mead, K.E.
Object Type: Report
System: The UNT Digital Library
Industrial safety and applied health physics. Annual report for 1980 (open access)

Industrial safety and applied health physics. Annual report for 1980

Information is reported in sections entitled: radiation monitoring; Environmental Management Program; radiation and safety surveys; industrial safety and special projects; Office of Operational Safety; and training, lectures, publications, and professional activities. There were no external or internal exposures to personnel which exceeded the standards for radiation protection as defined in DOE Manual Chapter 0524. Only 35 employees received whole body dose equivalents of 10 mSv (1 rem) or greater. There were no releases of gaseous waste from the Laboratory which were of a level that required an incident report to DOE. There were no releases of liquid radioactive waste from the Laboratory which were of a level that required an incident report to DOE. The quantity of those radionuclides of primary concern in the Clinch River, based on the concentration measured at White Oak Dam and the dilution afforded by the Clinch River, averaged 0.16 percent of the concentration guide. The average background level at the Perimeter Air Monitoring (PAM) stations during 1980 was 9.0 ..mu..rad/h (0.090 ..mu..Gy/h). Soil samples were collected at all perimeter and remote monitoring stations and analyzed for eleven radionuclides including plutonium and uranium. Plutonium-239 content ranged from 0.37 Bq/kg (0.01 pCi/g) to 1.5 Bq/kg (0.04 …
Date: November 1, 1981
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Sample preselection process designed to enhance early planning information. [Sampling program for evaluating nuclear weapon stockpiles] (open access)

Sample preselection process designed to enhance early planning information. [Sampling program for evaluating nuclear weapon stockpiles]

The DOE provides for the continuing evaluation of the nuclear weapon stockpiles through a stockpile sampling program in which randomly selected weapons are withdrawn for testing from the stockpiles each year. For some time, DOE has used a preselection scheme to obtain early identification of certain characteristics of the sample weapons for planning purposes, but which does so without jeopardizing the necessary randomization of sample selection. A DOD desire for additional and more detailed planning information to minimize weapon movements has led to an improvement of the original preselection scheme that enhances the planning information and its accuracy, while still preserving randomization.
Date: November 1, 1981
Creator: Mueller, F.W. & Spencer, F.W.
Object Type: Report
System: The UNT Digital Library
Geophysical flight line flying and flight path recovery utilizing the Litton LTN-76 inertial navigation system (open access)

Geophysical flight line flying and flight path recovery utilizing the Litton LTN-76 inertial navigation system

The Litton LTN-76 Inertial Navigation Systems (INS) with Inertial Track guidance System (ITGS) software is geared toward the airborne survey industry. This report is a summary of tests performed with the LTN-76 designed to fly an airborne geophysical survey as well as to recover the subsequent flight path utilizing INS derived coordinates.
Date: November 1, 1981
Creator: Mitkus, A.F.; Cater, D.; Farmer, P.F. & Gay, S.P. Jr.
Object Type: Report
System: The UNT Digital Library
Deuterium-beam species measured by fusion reactions in the neutralizer (open access)

Deuterium-beam species measured by fusion reactions in the neutralizer

Using a surface barrier detector and standard nuclear instrumentation, the energetic charged products of fusion reactions between deuterium neutralizer gas and accelerated deuterium ions are sorted in energy to yield a measurement of the species from a neutral beam source, i.e., the proportions of accelerated D/sup +/, D/sub 2//sup +/, and D/sub 3//sup +/. Such sources have been designed at LBL for the TFTR project at Princeton University to accelerate currents of 65 amps to 120 kilovolts, and the species distribution affects the power deposition within the target plasma. An integral measurement over the entire area of the beam can be performed with Doppler shift spectroscopy, but it involves a large number of cross sections, of which not all are known, and it is also dependent upon the neutralizer gas distribution. The present species measurement complements other measurements because it is integrated over the entire beam, is independent of the neutralizer gas distribution, and only requires one well known cross section.
Date: November 1, 1981
Creator: Smith, R. R. & Strathman, M. D.
Object Type: Article
System: The UNT Digital Library