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Structure and properties of nanophase TiO/sub 2/

Description: Ultrafine-grained, nanophase samples of TiO/sub 2/ (rutile) were synthesized by the gas-condensation method and subsequent in-situ compaction, and then studied by transmission electron microscopy, Vickers hardness measurements, and positron annihilation spectroscopy as a function of sintering temperature. The nanophase compacts densified rapidly above 500/sup 0/C, with only a small increase in grain size. The hardness values obtained by this method are comparable to or greater than coarser-grained compacts, but at temperatures 400 to 600/sup 0/C lower than conventional sintering temperatures and without the need for sintering aids. 11 refs., 3 figs.
Date: July 1, 1987
Creator: Siegel, R.W.; Hahn, H.; Ramasamy, S.; Zongquan, Li; Ting, Lu & Gronsky, R.
Partner: UNT Libraries Government Documents Department

Subsurface geological and geophysical study of the Cerro Prieto geothermal field, Baja California, Mexico

Description: The subsurface investigation of the Cerro Prieto field and surrounding area is described including the stratigraphy, structure, hydrothermal alteration, and reservoir properties for use in designing reservoir simulation models and planning development of the field. Insights into the depositional, tectonic, and thermal history of the area are presented. The following types of data were used: well sample descriptions and analyses, well logs, geophysical surveys; physiography, and regional geology. (MHR)
Date: January 1, 1980
Creator: Lyons, D.J. & van de Kamp, P.C.
Partner: UNT Libraries Government Documents Department

Si(Li)-NaI(Tl) detector for direct measurement of plutonium in vivo

Description: The potential of a Si(Li)-NaI(Tl) detector system for measuring the UL x rays produced in the decay of Pu is discussed. In this paper we describe the conceptual design and expected performance of such a system. The detector can resolve the UL x rays from the NpL x ray thus permitting direct measurement of Pu in the presence of /sup 241/Am. The expected performance of the system was determined from measurements of lung phantoms using a prototype Si detector.
Date: January 1, 1983
Creator: Sherman, I.S.; Strauss, M.G. & Pehl, R.H.
Partner: UNT Libraries Government Documents Department

Si(Li)-NaI(Tl) sandwich detector array for measurements of trace radionuclides in soil samples

Description: An ultra-sensitive x-/..gamma..-ray detector system for assaying trace radioactivity in actinide contaminated soil and ash samples has been developed. The new system consists of an array of 6 large Si(Li) x-ray detectors sensitive on both faces and mounted on edge in a paddle-shaped cryostat with a 14 cm dia Be window on each side. The paddle, with a sample of the soil placed at each window, is sandwiched between 2 large NaI(Tl) scintillators which suppress the ..gamma.. background. With x rays being measured simultaneously from soil in 2 sample holders and background reduced by 50% using anticoincidence, the sensitivity of this detector is 4 times higher than that of conventionally mounted Si(Li) detectors. A soil sample containing 50 pCi/g /sup 239/Pu was measured in 5 min with an uncertainty of <20% and a sample containing 7 pCi/g was measured in 1 hr. With FWHM resolution of 400 eV at 17 keV, the UL..beta../sub 1/ and NpL..beta../sub 1/ x-ray peaks are resolved thus permitting measurement of trace Pu in the presence of Am-241. This is the most sensitive and selective detector known for nondestructive assay of radioactivity in soil and other samples. 15 refs., 8 figs.
Date: January 1, 1985
Creator: Strauss, M.G.; Sherman, I.S.; Roche, C.T. & Pehl, R.H.
Partner: UNT Libraries Government Documents Department

Modeling of porous electrodes in molten-salt systems

Description: Porous electrodes are used for many batteries because they permit the reactants to be close to the site of the electrochemical reaction. The basis for a nonuniform reaction distribution in such electrodes is reviewed, and some results are discussed for lithium alloy, iron sulfide cells. Discrepancies between model and experimental results can be attributed to poor approximations to the effective conductivity of packed-bed electrodes and to inadequate treatment of the precipitation of KCl.
Date: August 1, 1986
Creator: Newman, J.
Partner: UNT Libraries Government Documents Department

Onset of incomplete momentum transfer in fusion-like processes

Description: Velocity spectra of evaporation residues from the reactions /sup 16/O + Al, Ca, and Ni have been measured at bombarding energies of 8.8, 13.6, and 19.6 MeV/u. Comparison with statistical model predictions shows clear evidence for the onset of incomplete momentum transfer at about 5 MeV/u above the interaction barrier. To first order, the results are similar for all targets, suggesting that the missing momentum is mainly associated with the projectile. The fraction of transferred linear momentum appears to decrease linearly with increasing relative velocity of the colliding nuclei at the barrier.
Date: March 1, 1983
Creator: Stokstad, R.G.; Chan, Y.; Murphy, M.; Tserruya, I.; Wald, S. & Budzanowski, A.
Partner: UNT Libraries Government Documents Department

Multiquasiparticle configuration effects deduced from the very high frequency discrete lines spectroscopy of /sup 165/Yb

Description: New experimental data are presented for /sup 165/Yb in which three already known rotational bands are extended up to very high angular frequencies. We do not observe, below h-bar omega/sub c/ approx. 0.45 MeV in any of these three bands the second discontinuity occuring for h-bar omega/sub c/ approx. 0.42 MeV in N = 90 nuclei. Furthermore, we observe in these three sequences a dealignment of high enough amplitude that it cannot be explained in terms of a single quasi-neutron configuration, and must then be due to a collective effect. A gradual decrease of the neutron pairing with increasing angular frequencies is suggested.
Date: January 1, 1982
Creator: Schuck, C.; Bendjallah, N.; Diamond, R.M.; Ellis-Akovali, Y.; Lindenberg, K.H.; Newton, J.O. et al.
Partner: UNT Libraries Government Documents Department

Study of incomplete fusion for light heavy-ion systems using velocity distributions

Description: Experimental results on incomplete fusion for light systems are discussed by studying the velocity distribution of fusion-like residues in the energy range of 6 to 20 MeV/nucleon. Original experimental work and results from other groups including the Hahn-Meitner Institute and the Argonne National Laboratory are also cited. Reactions between /sup 14/N, /sup 16/O, /sup 19/F, and /sup 20,22/Ne projectiles and /sup 24,26/Mg, /sup 27/Al, /sup 28/Si, /sup 40/Ca and /sup 58,60/Ni targets have been studied. 19 refs., 15 figs., 1 tab.
Date: March 1, 1986
Creator: Chan, Y.; Albiston, C.; Bantel, M.; Budzanowski, A.; DiGregorio, D.; Stokstad, R.G. et al.
Partner: UNT Libraries Government Documents Department

Mechanism of density decrease in heat-treated glass-like carbon (GC)

Description: Measurements were made of the density decrease (pycnometric), mass loss, hydrogen loss, dimensional increase and thermal expansion (dilatomeric) of glassy carbon heated in the range 1000/sup 0/C to 2800/sup 0/C or stressed (hydrostatic pressures) to 250,000 psi. The irreversibility density decrease is attributed to thermal expansion mismatch (..cap alpha../sub c/ >> ..cap alpha../sub a/) and microscopic fracture.
Date: March 1, 1981
Creator: Mehrotra, B.N.; Bragg, R.H. & Rao, A.S.
Partner: UNT Libraries Government Documents Department

Parameter studies of candidate lattices for the 1-2 GeV synchrotron radiation source

Description: This document discusses the implications of various collective phenomena on the required performance of candidate lattices for the LBL 1 to 2 GeV Synchrotron Radiation Source. The performance issues considered include bunch length, emittance growth, and beam lifetime. In addition, the possible use of the 1 to 2 GeV Synchrotron Radiation Source as a high-gain FEL is explored briefly. Generally, the differences between lattices are minor. It appears that the most significant feature distinguishing the various alternatives will be the beam lifetime.
Date: January 13, 1986
Creator: Zisman, M.S.
Partner: UNT Libraries Government Documents Department

Induction linacs

Description: The principle of linear induction acceleration is described, and examples are given of practical configurations for induction linacs. These examples include the Advanced Technology Accelerator, Long Pulse Induction Linac, Radial Line Accelerator (RADLAC), and Magnetically-Insulated Electron-Focussed Ion Linac. A related concept, the auto accelerator, is described in which the high-current electron-beam technology in the sub-10 MeV region is exploited to produce electron beams at energies perhaps as high as the 100 to 1000 MeV range. Induction linacs for ions are also discussed. The efficiency of induction linear acceleration is analyzed. (LEW)
Date: July 1, 1986
Creator: Keefe, D.
Partner: UNT Libraries Government Documents Department

High-spin nuclear spectroscopy

Description: High-spin spectroscopy is the study of the changes in nuclear structure, properties, and behavior with increasing angular momentum. It involves the complex interplay between collective and single-particle motion, between shape and deformation changes, particle alignments, and changes in the pairing correlations. A review of progress in theory, experimentation, and instrumentation in this field is given. (DWL)
Date: July 1, 1986
Creator: Diamond, R.M.
Partner: UNT Libraries Government Documents Department

Hyperons in neutron stars

Description: Generalized beta equilibrium involving nucleons, hyperons, and isobars is examined for neutron star matter. The hyperons produce a considerable softening of the equation of state. It is shown that the observed masses of neutron stars can be used to settle a recent controversy concerning the nuclear compressibility. Compressibilities less than 200 MeV are incompatible with observed masses. 7 refs., 9 figs.
Date: April 1, 1986
Creator: Glendenning, N.K.
Partner: UNT Libraries Government Documents Department

MEVVA ion source for high current metal ion implantation

Description: The MEVVA (Metal Vapor Vacuum Arc) ion source is a new kind of source which can produce high current beams of metal ions. Beams of a wide range of elements have been produced, spanning the periodic table from lithium up to and including uranium. The source extraction voltage is up to 60 kV, and we are increasing this up to 120 kV. A total ion beam current of over 1 Ampere has been extracted from the present embodiment of the concept, and this is not an inherent limit. The ion charge state distribution varies with cathode material and arc current, and beams like Li/sup +/, Co/sup +,2+,3+/ and U/sup 3+,4+,5+,6+/ for example, are typical; thus the implantation energy can be up to several hundred kilovolts without additional acceleration. The ion source has potential applications for ion implantation and ion beam mixing for achievement of improved corrosion resistance or wear resistance in metals or surface modification of ceramic materials and semiconductors. Here we outline the source and its performance, and describe some very preliminary implantation work using this source.
Date: July 1, 1986
Creator: Brown, I. & Washburn, J.
Partner: UNT Libraries Government Documents Department

SuperHILAC Upgrade Project

Description: A high current MEtal Vapor Vacuum Arc (MEVVA) ion source is to be installed in the third injector (Abel) at the SuperHILAC, representing the first accelerator use of this novel ion source. The MEVVA source has produced over 1 A of uranium in all charge states, with typically more than 100 electrical mA (emA) of U/sup 5 +/. A substantial fraction of this high current, heavy ion beam must be successfully transported to the entrance of the Wideroe linac to approach the 10 emA space-charge output limit of the Wideroe. Calculations show that up to 50 emA of U/sup 5 +/ can be transported through the present high voltage column. A bouncer will be added to the Cockcroft-Walton supply to handle the increased beam current. The Low Energy Beam Transport line vacuum will be improved to reduce charge exchange, and the phase matching between the 23 MHz Wideroe and the 70 MHz Alvarez linacs will be improved by the addition of two 70 HMz bunchers. The installation of the MEVVA source along with the modifications described above are expected to result in a five-fold increase in beam delivered to Bevatron experiments, increasing the extracted uranium beam to 5 x 10/sup 7/ ions/pulse.
Date: June 1, 1986
Creator: Feinberg, B. & Brown, I.G.
Partner: UNT Libraries Government Documents Department

Primordial nucleosynthesis during the keV era

Description: Energetic hadronic and electromagnetic showers in the keV era of the hot big bang are produced by the decays of long lived particles. These showers initiate a new phase of nucleosynthesis. The abundance ratios of D, /sup 3/He, /sup 6/Li and /sup 7/Li are given by fixed points of rate equations, which are determined by nuclear physics not by the nature of the decaying particle. The fixed points are independent of prior abundances, so that constraints from the MeV era of nucleosynthesis evaporate, except for a requirement that /sup 4/He not be underproduced. For example, ..cap omega../sub B/ = 1 and many more than four neutrino species are both possible. Within the accuracy of our calculation (there are uncertainties of at least a factor of three), the abundances agree with those inferred from observations. Considerable /sup 6/Li is produced and must be depleted in both population II halo stars and in the galactic disk. We predict /sup 6/Li, /sup 3/He and D abundances in primordial material which are higher than conventional nucleosynthesis. 8 refs.
Date: September 9, 1987
Creator: Dimopoulos, S.; Esmailzadeh, R.; Hall, L.J. & Starkman, G.D.
Partner: UNT Libraries Government Documents Department

Correction of the field in the SSC dipoles using superconductor on the wedges

Description: The SSC colliding beam storage ring requires superconducting magnets capable of producing a magnetic field of 6.6 T which has very high accuracy. For many of the multipoles, that multipole must be reduced (at a radius of 1 centimeter) to the order of 0.2 parts in 10,000. This field accuracy is dictated by the physics of storing very small high-current proton beams at energies ranging from 1 TeV to 20 TeV. Magnetization of the superconductor can cause sextupole field errors of up to 6 parts in 10,000 at an injection field of 0.33 T at a radius of 1 centimeter. Saturation of the magnet iron can induce sextupole field errors of 1 to 2 parts in 10,000 at the full field of 6.6 T. Manufacturing errors can induce other multipole components, both normal and skew. The SSC coil has three wedges separating the superconducting coil blocks on the inner layer of the coil. These wedges must be accurately located. If the wedges have superconductors attached, one can correct all of the magnetic field multipoles (both normal and skew) from N = 1 (dipole) to N = 6 (12 pole). This paper describes this method of correction as it pertains to the SSC dipole magnet. 9 refs., 5 figs., 3 tabs.
Date: September 1, 1987
Creator: Green, M.A. & Talman, R.M.
Partner: UNT Libraries Government Documents Department

Recent developments of the LBL ECR ion source

Description: The performance of the LBL ECR has improved significantly since January 85 when the last ECR Ion Source Workshop was held in Berkeley. The 88-Inch Cyclotron began regular operation with the ECR source just prior to the workshop. Since then about 80% of the cyclotron operating schedule has been with the ECR source. The light-ion filament source is used only for runs two or more shifts in length using proton, /sup 3/He, or alpha beams. Occasionally the polarized ion source is used. The heavy-ion PIG sources are not longer used. The operating experience with the Cyclotron+ECR has been highly successful in terms of reliability, stability, production of high charge state currents, and in the range of ions which can be produced. For example, a 32.5 MeV/u /sup 16/O/sup 8 +/ beam was developed and successfully used for a nuclear structure experiment. The 60 nA beam available from the cyclotron was more intense than the experiment could use. A 1.08 GeV /sup 36/Ar/sup 18 +/ beam was used to test the response of various scintillator materials to intermediate energy heavy ions. Three aspects of the LBL ECR source development are discussed. First, the installation of a new first stage cavity has resulted in improved source performance. Second, a number of metal ion beams have been developed and are used regularly for nuclear science experiments with the cyclotron. Third, the source performance has been compared to charge state distribution (CSD) calculations using a computer code.
Date: May 1, 1986
Creator: Lyneis, C.M.
Partner: UNT Libraries Government Documents Department

Research toward new alloys for generator retaining rings

Description: The research reported here was undertaken to develop an alloy suitable for use in the retaining rings of two-pole electrical generators that would have three key properties: a yield strength of 200 ksi or greater with good residual toughness; resistance to hydrogen embrittlement and stress-corrosion cracking; and processability through heat treatment after hot forming, to avoid the necessity of cold forming of the ring. The principal alloy developed during the course of this work was an iron-based superalloy, designated EPRI-T, which has nominal composition Fe-34.5Ni-5Cr-3Ti-3Ta-0.5A1-1.0Mo-0.3V-0.01B. The alloy is an iron-based superalloy which is strengthened through the formation of cubic ..gamma..' precipitates of composition Ni/sub 3/(Ti,Ta,Al). When given appropriate aging treatment from the as-forged condition the alloy achieves yield strength in excess of 200 ksi with good residual toughness and promising resistance to cracking in gaseous hydrogen and salt water. The composition and processing of the alloy are the result of sequential metallurgical development, the steps of which are described. The alloy was chosen from a class of iron-based superalloys to achieve high strength in thick sections while maintaining reasonable costs, melting practice, and hot formability. The nickel content of the alloy was adjusted to insure that the alloy would be paramagnetic austenite after aging reaction to form the Ni/sub 3/X strengthening precipitates. Tantalum was included among the ..gamma..'-forming elements to increase the lattice mismatch of the precipitate and improve alloy strength. Chromium was added to the composition to stabilize the austenite phase and eliminate stress-corrosion cracking susceptibility due to martensitic transformation of the austenite. The Mo-V-B group was included to inhibit intergranular precipitation of the equilibrium eta phase and hence suppress a tendency toward intergranular fracture in the alloy.
Date: November 1, 1981
Creator: Morris, J.W. Jr. & Chang, K.M.
Partner: UNT Libraries Government Documents Department

Masses and decay properties of nuclei far from stability

Description: A macroscopic-microscopic calculation has been applied to a study of the stability of elements in the heavy and superheavy regions. A folded-Yukawa single-particle potential and a Finite-Range microscopic model were used. Calculated neutron single-particle levels are shown for the spherical nucleus of Z = 114 and A = 298. These are compared to results from an earlier version of the folded-Yukawa potential and to the results of a Woods-Saxon model. Calculated ground-state shell corrections are shown. A small local minimum is seen around Z = 110 and N = 162, which is thought to have a 40 ms half-life. The microscopic correction was calculated for single-particle wells appropriate to 15 nuclei on the line of beta stability. Results obtained with the identical microscopic corrections with the Finite-Range Droplet model for the macroscopic energy are also shown. 12 refs., 4 figs. (LEW)
Date: January 1, 1986
Creator: Moeller, P.; Nix, J.R.; Myers, W.D. & Swiatecki, W.J.
Partner: UNT Libraries Government Documents Department

Conference on energy research at historically black universities

Description: A conference was convened to present and discuss significant research and development in Historically Black Institutions (current and past); areas that show potential for inter-institutional collaboration and the sharing of facilities; existing capabilities to sustain funded research activities and future potential for expansion and enhancement; and appropriate arrangements for maximum interaction with industry and government agencies. Papers were presented at small group meetings in various energy research areas, and abstracts of the projects or programs are presented. The Solar Energy small group provided contributions in the areas of photovoltaics, biomass, solar thermal, and wind. Research reported on by the Fossil Fuel small group comprises efforts in the areas of fluidized bed combustion of coal, coal liquefaction, and oil shale pyrolysis. Five research programs reported on by the Conservation Research small group involve a summer workshop for high school students on energy conservation; use of industrial waste heat for a greenhouse; solar energy and energy conservation research and demonstration; energy efficiency and management; and a conservation program targeted at developing a model for educating low income families. The Environment Impact groups (2) presented contributions on physical and chemical impacts and biological monitors and impacts. The Policy Research group presented four papers on a careful analysis of the Equity issues; one on a model for examining the economic issue in looking at the interaction between energy technology and the state of the economy; and a second paper examined the institutional constraints on environmental oriented energy policy. Six additional abstracts by invited participants are presented. (MCW)
Date: January 1, 1980
Partner: UNT Libraries Government Documents Department

Injection and energy recovery in fractured geothermal reservoirs

Description: Numerical studies of the effects of injection on the behavior of production wells completed in fractured two-phase geothermal reservoirs are presented. In these studies the multiple-interacting-continua (MINC) method is employed for the modeling of idealized fractured reservoirs. Simulations are carried out for a five-spot well pattern with various well spacings, fracture spacings, and injection fractions. The production rates from the wells are calculated using a deliverability model. The results of the studies show that injection into two-phase fractured reservoirs increases flow rates and decreases enthalpies of producing wells. These two effects offset each other so that injection tends to have small effects on the usable energy output of production wells in the short term. However, if a sufficiently large fraction of the produced fluids is injected, the fracture system may become liquid-filled and an increased steam rate is obtained. Our studies show that injection greatly increases the long-term energy output from wells, as it helps extract heat from the resrvoir rocks. If a high fraction of the produced fluids is injected, the ultimate energy recovery will increase manyfold.
Date: January 1, 1983
Creator: Bodvarsson, G.S.; Pruess, K. & O'Sullivan, M.J.
Partner: UNT Libraries Government Documents Department

Small-angle x-ray scattering system with linear position-sensitive detector

Description: A linear position-sensitive detector has been constructed for use in small-angle x-ray scattering experiments. It is a one dimensional, pressurized gas-filled detector with a delay line read out. Calculated efficiency of the detector at 8.04 keV and 45 psi for Ar-CH/sub 4/ filling is 60%, and for Xe-CO/sub 2/ filling is 90% limited only by the thickness of the entrance beryllium window. Inherent resolution of the detector is 0.1 mm for normal incident x-rays. The overall resolution of the detection system is determined by the width and angular divergencies of the point collimated CU K/sub ..cap alpha../ beam used in the experiment. The performance of the system is described in terms of measurements on Al-Zn alloy samples.
Date: April 1, 1981
Creator: Forouhi, A.R.; Sleaford, B.; Perez-Mendez, V.; de Fontaine, D. & Fodor, J.
Partner: UNT Libraries Government Documents Department

Some possibilities for doing polarized p, anti p experiments at the SSC

Description: While there has been a previous study of accelerating polarized beam at the SSC, we have looked at several alternative approaches, including polarizing stored beam, using polarized gas jets, and using secondary polarized beams. We also point out some physics possibilities and give references to physics reviews.
Date: January 1, 1984
Creator: Shapiro, G. & Underwood, D.
Partner: UNT Libraries Government Documents Department