Resource Type

Effect of precipitate-matrix interface sinks on the growth of voids in the matrix (open access)

Effect of precipitate-matrix interface sinks on the growth of voids in the matrix

A qualitative discussion of the differing roles played by coherent and incoherent precipitates as point defect sinks is presented. Rate theory is used to obtain semiquantitative estimates of the growth of cavities in the matrix when either type of precipitate is present. Methods for deriving the sink strengths of precipitates of arbitrary shape are developed. In three materials where available microstructural information allows an analysis, precipitates are found to cause only a small relative suppression of cavity growth via the mechanisms here considered.
Date: January 1, 1981
Creator: Brailsford, A.D. & Mansur, L.K.
System: The UNT Digital Library
Hydrogen concentration and distribution in high-purity germanium crystals (open access)

Hydrogen concentration and distribution in high-purity germanium crystals

High-purity germanium crystals used for making nuclear radiation detectors are usually grown in a hydrogen ambient from a melt contained in a high-purity silica crucible. The benefits and problems encountered in using a hydrogen ambient are reviewed. A hydrogen concentration of about 2 x 10/sup 15/cm/sup -3/ has been determined by growing crystals in hydrogen spiked with tritium and counting the tritium ..beta..-decays in detectors made from these crystals. Annealing studies show that the hydrogen is strongly bound, either to defects or as H/sub 2/ with a dissociation energy > 3 eV. This is lowered to 1.8 eV when copper is present. Etching defects in dislocation-free crystals grown in hydrogen have been found by etch stripping to have a density of about 1 x 10/sup 7/ cm/sup -3/ and are estimated to contain 10/sup 8/ H atoms each.
Date: October 1, 1981
Creator: Hansen, W. L.; Haller, E. E. & Luke, P. N.
System: The UNT Digital Library
Learning from numerical calculations of ion-atom collisions (open access)

Learning from numerical calculations of ion-atom collisions

Violent collision of two independent many-particle systems, victims, are discussed in the atomic sphere. The asymmetric region where the charge of the projectile Z/sub p/ is less than the target nuclear charge Z/sub n/ is now well understood though interesting details still need to be worked out. Negatively charged projectiles offer a new illustration of Fadeev re-arrangement collisions. Multi-electron coherence effects illustrate the richness of the field but a symmetric (Z/sub p/ approx. Z/sub n/) collision treatment is needed. A new one and a half center expansion method promises a solution to this problem. Future areas of interest are discussed.
Date: January 1, 1981
Creator: Reading, J.F.; Ford, A.L.; Martir, M. & Becker, R.L.
System: The UNT Digital Library
Role of animal studies in low-dose extrapolation (open access)

Role of animal studies in low-dose extrapolation

Current data indicate that in the case of low-LET radiation linear, extrapolation from data obtained at high doses appears to overestimate the risk at low doses to a varying degree. In the case of high-LET radiation, extrapolation from data obtained at doses as low as 40 rad (0.4 Gy) is inappropriate and likely to result in an underestimate of the risk.
Date: January 1, 1981
Creator: Fry, R.J.M.
System: The UNT Digital Library
Clay-mineral fabrics and chemistry in Salton Trough geothermal fields (open access)

Clay-mineral fabrics and chemistry in Salton Trough geothermal fields

Fluid production from, and hence the economic viability of, a geothermal field is related to the amount of clay minerals in the caprock and in the reservoir rocks. In both the East Mesa and Cerro Prieto fields in the Salton Trough of southern California, United States, and Baja California, Mexico, scanning electron micrography (SEM) has vividly documented the role of clay fabrics in deltaic quartz-sandstone reservoirs. For example, in East Mesa well 78-30 at 1630 m depth in a zone of quartz dissolution, the clay present in pores exhibits an irregular, crenulate, honeycomb fabric and has the following composition from energy dispersive x-ray analysis (EDAX): Si 61%, Al 25%, Fe 20%, Na 6%, K 2%, and Mg 1%. Platy clusters of clay (kaolinite) in Cerro Prieto well T-366 at 2522 m in a 300/sup 0/C geothermal aquifer were analyzed as: Si 62%, Al 25%, Mg 6%, and Fe 1%. In other samples, illite takes the form of wispy fibers whose intertwined ends form bridges across pores. These clay fabrics appear to reduce permeability significantly by clogging the pore throats, even though dissolution porosity ranges from 25 to 35%. Nineteen wells have been studied to date.
Date: July 1, 1981
Creator: Haar, S.V.; Wolgemuth, K. & Schatz, J.
System: The UNT Digital Library
Summary of proceedings: Oklahoma and Texas wind energy forum, April 2-3, 1981 (open access)

Summary of proceedings: Oklahoma and Texas wind energy forum, April 2-3, 1981

The Wind Energy Forum for Oklahoma and Texas was held at the Amarillo Quality Inn in Amarillo, Texas on April 2-3, 1981. Its purpose was to bring together the diverse groups involved in wind energy development in the Oklahoma and Texas region to explore the future commercial potential and current barriers to achieving this potential. Major topics of discussion included utility interconnection of wind machines and the buy-back rate for excess power, wind system reliability and maintenance concerns, machine performance standards, and state governmental incentives. A short summary of each presentation is included.
Date: June 1, 1981
Creator: Nelson, S. C. & Ball, D. E.
System: The UNT Digital Library
Bromoform production in tropical open-ocean waters: OTEC chlorination (open access)

Bromoform production in tropical open-ocean waters: OTEC chlorination

The bromoform, and other volatile organics produced while chlorinating both the evaporator and condenser seawater during operation of the one megawatt (1 MW) OTEC-1 test facility are reported. Although many halogenated compounds might be produced as a result of chlorination, the quantitative analyses in this study focused on volatile EPA priority pollutants. Bromoform is the compound specifically recognized as a potential pollutant. Its concentration may be indicative of other halogenated species.
Date: September 1, 1981
Creator: Hartwig, E.O. & Valentine, R.
System: The UNT Digital Library
Theoretical Considerations on the Performance of Negative Sputter Ion Sources (open access)

Theoretical Considerations on the Performance of Negative Sputter Ion Sources

Theoretical analyses of experimentally observed negative ion yield data from cesium rich plasma discharge sources such as those based on the University of Aarhus source concept appear to correlate experiment and theory through surface ionization mechanisms for many species. The agreement between experiment and theory is rather remarkable considering the idealistic model used. A few atomic species appear to overproduce relative to the simple theoretical model. These deviations suggest that still other mechanisms may be important for certain elements such as the affinity level mechanism recently reported.
Date: January 1, 1981
Creator: Alton, G. D.
System: The UNT Digital Library
FFTF power-range testing (open access)

FFTF power-range testing

FFTF's ascent to full power was a distinct success. Plant performance and the short time frame required to complete testing clearly illustrated the efforts of all involved in preparing for the initial power ascent. The data obtained will be used as a baseline for further power range testing as the FFTF startup program is completed.
Date: June 1, 1981
Creator: Rapacz, A. J.; Redekopp, R. D. & Waldo, J. B.
System: The UNT Digital Library
Baryon production at PEP (open access)

Baryon production at PEP

Measurements of inclusive ..lambda.. + anti ..lambda.. production for 1.0 less than or equal to p less than or equal to 10.0 GeV/c and p + anti p production for 0.4 less than or equal to p less than or equal to 2.0 GeV/c show significant baryon production in e/sup +/e/sup -/ annihilation at E/sub cm/ = 29 GeV. ..lambda.. + anti ..lambda.. production represents 0.2 ..lambda..'s or anti ..lambda..'s per PEP event while the observed p + anti p production implies all baryon-antibaryon pair production is occurring at least as often as 0.6 per event, depending on the yet to be measured p + anti p production at high momentum. Comparisons are made with the first theoretical attempts to account for baryon production at these energies.
Date: September 1, 1981
Creator: Goldhaber, G. & Weiss, J.M.
System: The UNT Digital Library
Minutes of the fourth SALE program participants meeting (open access)

Minutes of the fourth SALE program participants meeting

This report is a documentation of the presentations made to the Fourth Safeguards Analytical Laboratory Evaluation (S.A.L.E.) Program Participants Meeting at Argonne, Illinois, July 8-9, 1981. The meeting was sponsored by the US Department of Energy and was coordinated by the S.A.L.E. Program of the New Brunswick Laboratory. The objective of the meeting was to provide a forum through which administration of the Program and methods appropriate to the analysis of S.A.L.E. Program samples could be discussed. The Minutes of the Meeting is a collection of presentations by the speakers at the meeting and of the discussions following the presentations. The presentations are included as submitted by the speakers. The discussion sections were transcribed from tape recordings of the meeting and were edited to clarify and emphasize important comments. Seventeen papers have been abstracted and indexed.
Date: October 1, 1981
Creator: unknown
System: The UNT Digital Library
Triple-jet structures in proton-proton interactions (open access)

Triple-jet structures in proton-proton interactions

In this experiment, which uses a superconducting solenoid at the CERN ISR, a large sample of two-jet events produced in proton-proton collisions at 62 GeV centre-of-mass energy has been examined for evidence of three-jet structures; that is, for the presence of events in which three particle jets can be separately identified at large transverse momenta relative to the initial proton directions, there also being spectator jets following these directions, making five jets in all. Such three-jet events are expected to be produced by gluon bremsstrahlung, as has been observed in the e/sup +/e/sup -/ case, but several additional mechanisms are expected in the case of hadronic collisions. The three-jet events are identified by cluster analysis, the particles of each event being sorted into the best three-cluster and two-cluster combinations. Results are briefly described. (WHK)
Date: July 1, 1981
Creator: Angelis, A. L. S.; Besch, H. J. & Blumenfeld, B. J.
System: The UNT Digital Library
Hydrofracture from a growing cavity (open access)

Hydrofracture from a growing cavity

The Los Alamos KRAK code has been used to calculate fracturing away from the growing cavity formed by a nuclear detonation. In the 55 ms before rebound, the stress in the surrounding rock is decreasing, and conditions for fracture propagation are good. During this interval, hydrofractures driven by the high-temperature, high-pressure gases within the cavity grow readily. Fracture growth slows when the stress increases as the residual hoop is formed during rebound. However, cracks are found to escape through the residual stress field. The effects of initial conditions and zoning on the numerical calculations are discussed, and the roles of the media saturation and roughness are briefly considered. The largest uncertainty in these calculations is the manner in which the effective pressure used in computing crack widths is extended into the cavity region. Because the present calculations have been done using a very conservative scheme, actual fractures should grow even more readily. We conclude that hydrofracture is an important, if not dominant, process in transporting mass and energy out of a cavity formed by a nuclear detonation.
Date: January 1, 1981
Creator: Kunkle, T.D. & Travis, B.J.
System: The UNT Digital Library
Geological and geophysical signatures of the Jemez lineament: a reactivated Precambrian structure (open access)

Geological and geophysical signatures of the Jemez lineament: a reactivated Precambrian structure

The Jemez lineament (N52/sup 0/E) is one of several northeast-trending lineaments that traverse the southwestern United States. It is defined by a 500-km-long alignment of late Cenozoic volcanic fields extending southwest from at least the Jemez Mountains in the north-central New Mexico to the San Carlos-Peridot volcanic field in east-central Arizona. Geochronologic data from Precambrian basement rocks indicate that the lineament is approximately coincident with a boundary between Precambrian crustal provinces. Characteristics of the lineament are high heat flow (>104.5 mW/m/sup 2/), an attenuated seismic velocity zone from 25 to 140 km depth, and an upwarp of the crustal electrical conductor inferred from magnetotelluric studies. The high electrical conductivity is probably caused by the presence of interstitial magma in the rocks of the mid-to-upper crust. The average electical strike within the Precambrian basement is N60/sup 0/E, supporting a relationship between the Precambrian structural grain and the Jemez lineament. The geological and geophysical data suggest that the lineament is a structural zone that extends deep into the lithosphere and that its location was controlled by an ancient zone of weakness in the Precambrian basement. Ages of late Cenozoic volcanic rocks along the lineament show no systematic geographic progression, thus indicating that …
Date: January 1, 1981
Creator: Aldrich, M. J., Jr.; Ander, M. E. & Laughlin, A. W.
System: The UNT Digital Library
Conservative Differencing of the Electron Fokker-Planck Transport Equation (open access)

Conservative Differencing of the Electron Fokker-Planck Transport Equation

We need to extend the applicability and improve the accuracy of kinetic electron transport codes. In this paper, special attention is given to modelling of e-e collisions, including the dominant contributions arising from anisotropy. The electric field and spatial gradient terms are also considered. I construct finite-difference analogues to the Fokker-Planck integral-differential collision operator, which conserve the particle number, momentum and energy integrals (sums) regardless of the coarseness of the velocity zoning. Such properties are usually desirable, but are especially useful, for example, when there are spatial regions and/or time intervals in which the plasma is cool, so that the collision operator acts rapidly and the velocity distribution is poorly resolved, yet it is crucial that gross conservation properties be respected in hydro-transport applications, such as in the LASNEX code. Some points are raised concerning spatial differencing and time integration.
Date: January 12, 1981
Creator: Langdon, A. B.
System: The UNT Digital Library
Can a safeguards accountancy system really detect an unauthorized removal (open access)

Can a safeguards accountancy system really detect an unauthorized removal

Theoretical investigations and system studies indicate safeguards material balance data from reprocessing plants can be used to detect unauthorized removals. Plant systems have been modeled and simulated data used to demonstrate the techniques. But how sensitive are the techniques when used with actual plant data. What is the effect of safeguards applications on plant operability. Can safeguards be acceptable to plant operators, and are there any benefits to be derived. The Barnwell Nuclear Fuel Plant (BNFP) has been devoted to answering these and other questions over the past several years. A computerized system of near-real-time accounting and in-process inventory has been implemented and demonstrated during actual plant test runs. Measured inventories and hourly material balance closures have been made to assess safeguards in an operating plant application. The tests have culminated in actual removals of material from the operating plant to investigate the response and measure the sensitivity of the safeguards and data evaluation system.
Date: November 1, 1981
Creator: Ehinger, M.H. & Ellis, J.H.
System: The UNT Digital Library
Effect of calorimeter resolution and pile-up on trigger rates (open access)

Effect of calorimeter resolution and pile-up on trigger rates

In the high rate Isabelle environment it has long been recognized that fast time resolution and short memory times are highly desirable. Unfortunately, calorimeters have been inherently slow devices on the time scales of interest. The bunched beam scheme of Isabelle, Phase I, offers some temporary respite. The instantaneous luminosity is quite high and leads to an interaction probability of .2 per crossing. However, there is no hope of tagging multiple interactions within a bunch using time resolution alone. In that sense a time resolution of 200 ns is as good as 5 ns, and conventional calorimeter technologies (including gas multiplication readout) can be used.
Date: October 1, 1981
Creator: Carithers, W.
System: The UNT Digital Library
Neutral beam development at BNL (open access)

Neutral beam development at BNL

The long-term objective of the BNL Neutral Beam Development Group is to design and test a neutral beam system, using negative ion sources with a high beam current density. The principal elements of such a system are: a source of negative ions, beam extraction and transport system, accelerator, neutralizer, and the system for the removal and dumping (or energy recovery) of the remaining charged components of the beam. In the past year, a transition has been made from high current density, but pulsed, negative ion sources to sources designed to operate steady state. Two variants of the basic magnetron source geometry are being studied: the standard one with the discharge established in the interelectrode gap and the other with plasma injection from a hollow cathode discharge (HCD). Both sources have so far operated with steady state discharges.
Date: January 1, 1981
Creator: Alessi, J.G.; Hershcovitch, A.; Kovarik, V.; Larson, R.A.; McKenzie-Wilson, R.; Prelec, K. et al.
System: The UNT Digital Library
Infiltration measurements in audit and retrofit programs (open access)

Infiltration measurements in audit and retrofit programs

A model that relates fan pressurization measurements to infiltration values during the heating season is the basis for infiltration estimates in several different audit programs. The model is described and validation results are presented. The model is used in three different audit strategies. The first is an energy audit to determine economically optimal retrofits for residential buildings, based on actual, on-site measurments of key indices of the house. Measurements are analyzed on a microprocessor and retrofit combinations compatible with minimum life-cycle cost and occupant preferences are determined. The second uses graphical techniques to make infiltration calculations while the third is a non-instrumented walk-through audit that was developed as a standard reference in the Residential Conservation Service Program.
Date: April 1, 1981
Creator: Grimsrud, D. T.; Sonderegger, R. C. & Sherman, M. H.
System: The UNT Digital Library
Lepton spectrum (open access)

Lepton spectrum

Selected topics on the lepton spectrum are presented with special emphasis on tau decays and unpublished Mark II results from SPEAR and PEP. 42 references.
Date: October 1, 1981
Creator: Feldman, G. J.
System: The UNT Digital Library
Interim reliability evaluation program, Browns Ferry fault trees (open access)

Interim reliability evaluation program, Browns Ferry fault trees

An abbreviated fault tree method is used to evaluate and model Browns Ferry systems in the Interim Reliability Evaluation programs, simplifying the recording and displaying of events, yet maintaining the system of identifying faults. The level of investigation is not changed. The analytical thought process inherent in the conventional method is not compromised. But the abbreviated method takes less time, and the fault modes are much more visible.
Date: January 1, 1981
Creator: Stewart, M.E.
System: The UNT Digital Library
Influence of chemical characterization of oil shale solids on understanding water quality impacts (open access)

Influence of chemical characterization of oil shale solids on understanding water quality impacts

Synfuels technologies will yield products and effluents that are a function of the raw material being processed and the process variables. Chemical and mineralogic characterization of solids generated in synfuels production provide valuable insight into health and environmental impacts associated with synfuels processing (coal liquefaction or gasification and shale oil extraction). This report deals with considerations relating to leachate generation from solid wastes, but the suggested research approach is applicable to understanding the nature and extent of all effluents from synfuels operations. Solid characterization studies of one raw shale core and two spent shale cores from Occidental Oil Shale, Inc.'s Logan Wash site are described. These data are used to determine the effect of processing on the shale solids and also to evaluate a variety of water quality issues associated with in situ processing. The importance of solid characterization studies in developing an understanding of effluent composition and behavior and subsequently defining environmental impacts is described.
Date: January 1, 1981
Creator: Peterson, E. J. & Wagner, P.
System: The UNT Digital Library
Prediction of centrifugal pump-cleaning ability in waste sludge (open access)

Prediction of centrifugal pump-cleaning ability in waste sludge

Radioactive waste at the Savannah River Plant (SRP) is being transferred from older waste tanks to new, stress-relieved tanks for more effective waste management. The technology developed for waste removal involves the use of long-shaft, recirculating, centrifugal pumps (slurry pumps). Testing completed at the Savannah River Laboratory's 30-meter-diameter mock-up waste tank related the effective cleaning radius (ECR) of a slurry pump to critical pump and materials characteristics. Presently, this theory is being applied to radioactive waste at SRP. However, the technology can be applied to other remote handling situations where the slurry rheology can be determined. For SRP waste, an equation of the form: ECR ..cap alpha.. DV/sub 0/ (rho/tau/sub 0/)/sup 1/2/ was determined where D is the nozzle diameter, V/sub 0/ is the average initial velocity, rho is the density of the slurry, and tau/sub 0/ is the yield stress of the slurry. Using this relationship, the cleaning performance of a pump operating in any SRP sludge environment can be predicted. Specifically, yield stress and density measurements on sludge samples can be used to predict the required number and effective location for slurry pumps in actual SRP waste tanks.
Date: January 1, 1981
Creator: Churnetski, B V
System: The UNT Digital Library
Coatings for laser fusion (open access)

Coatings for laser fusion

Optical coatings are used in lasers systems for fusion research to control beam propagation and reduce surface reflection losses. The performance of coatings is important in the design, reliability, energy output, and cost of the laser systems. Significant developments in coating technology are required for future lasers for fusion research and eventual power reactors.
Date: December 18, 1981
Creator: Lowdermilk, W.H.
System: The UNT Digital Library