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Photoelectron photoion molecular beam spectroscopy

Description: The use of supersonic molecular beams in photoionization mass spectroscopy and photoelectron spectroscopy to assist in the understanding of photoexcitation in the vacuum ultraviolet is described. Rotational relaxation and condensation due to supersonic expansion were shown to offer new possibilities for molecular photoionization studies. Molecular beam photoionization mass spectroscopy has been extended above 21 eV photon energy by the use of Stanford Synchrotron Radiation Laboratory (SSRL) facilities. Design considerations are discussed that have advanced the state-of-the-art in high resolution vuv photoelectron spectroscopy. To extend gas-phase studies to 160 eV photon energy, a windowless vuv-xuv beam line design is proposed.
Date: December 1, 1980
Creator: Trevor, D.J.
Partner: UNT Libraries Government Documents Department
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Seismic isolation of an electron microscope

Description: A unique two-stage dynamic-isolation problem is presented by the conflicting design requirements for the foundations of an electron microscope in a seismic region. Under normal operational conditions the microscope must be isolated from ambient ground noise; this creates a system extremely vulnerable to seismic ground motions. Under earthquake loading the internal equipment forces must be limited to prevent damage or collapse. An analysis of the proposed design solution is presented. This study was motivated by the 1.5 MeV High Voltage Electron Microscope (HVEM) to be installed at the Lawrence Berkeley Laboratory (LBL) located near the Hayward Fault in California.
Date: January 1, 1980
Creator: Godden, W.G.; Aslam, M. & Scalise, D.T.
Partner: UNT Libraries Government Documents Department
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Model of gypsum, calcite and silica solubilities for application to geothermal waters over a wide range of temperature, P/sub CO/sub 2// and ionic strength. Final technical report, October 1, 1983-September 30, 1984

Description: This report describes the construction of a high temperature (25 to 250/sup 0/C), variable P/sub CO/sub 2// (1 to 40 atm), chemical model of mineral (including gypsum, calcite and amorphous silica) solubilities in the system: Na-K-Ca-H-Cl-SO/sub 4/-HCO/sub 3/-CO/sub 3/-CO/sub 2/-SiO/sub 2/-H/sub 2/O. This model was designed to support geothermal energy production needs.
Date: January 1, 1984
Partner: UNT Libraries Government Documents Department
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Coal surface control for advanced fine coal flotation

Description: The primary objective in the scope of this research project is to develop advanced flotation methods for coal cleaning in order to achieve near total pyritic-sulfur removal at 90% Btu recovery, using coal samples procured from three major US coal seams. Concomitantly, the ash content of these coals is to be reduced to 6% or less. Investigation of mechanisms for the control of coal and pyrite surfaces prior to fine coal flotation is the main aspect of the project objectives. The results of this research are to be made available to ICF Kaiser Engineers who are currently working on the Engineering Development of Advanced Flotation under a separate contract with DOE under the Acid Rain Control Initiative program. A second major objective is to investigate factors involved in the progressive weathering and oxidation of coal that had been exposed to varying degrees of weathering, namely, open to the atmosphere, covered and in an argon-inerted'' atmosphere, over a period of twelve months. After regular intervals of weathering, samples of the three base coals (Illinois No. 6, Pittsburgh No. 8 and Upper Freeport PA) were collected and shipped to both the University of Pittsburgh and the University of California at Berkeley for characterization studies of the weathered material. 29 figs., 29 tabs.
Date: July 30, 1991
Creator: Fuerstenau, D. W.; Sastry, K. V. S.; Hanson, J. S.; Diao, J.; De, A.; Sotillo, F. et al.
Partner: UNT Libraries Government Documents Department
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Land use and environmental impacts of decentralized solar energy use

Description: The physical, spatial and land-use impacts of decentralized solar technologies applied at the community level by the year 2000 are examined. The results of the study are intended to provide a basis for evaluating the way in which a shift toward reliance on decentralized energy technologies may eventually alter community form. Six land-use types representative of those found in most US cities are analyzed according to solar penetration levels identified in the maximum solar scenario for the year 2000. The scenario is translated into shares of end use demand in the residential, commercial and industrial sectors. These proportions become the scenario goals to be met by the use of decentralized solar energy systems. The percentage of total energy demand is assumed to be 36.5 percent, 18.8 percent and 22.6 percent in the residential, commercial and industrial sectors respectively. The community level scenario stipulated that a certain percentage of the total demand be met by on-site solar collection, i.e. photovoltaic and thermal collectors, and by passive design. This on-site solar goal is 31.9 percent (residential), 16.8 percent (commercial) and 13.1 percent (industrial).
Date: January 1, 1980
Creator: Twiss, R.H.; Smith, P.L.; Gatzke, A.E. & McCreary, S.T.
Partner: UNT Libraries Government Documents Department
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Polarizability of nuclear wave functions in heavy ion reactions. [/sup 208/Pb(/sup 12/C,/sup 11/B)/sup 209/Be, 78 MeV]

Description: Evidence is presented for the polarizability of nuclear wave functions in heavy-ion transfer reactions. The polarization of the wave function of the transferred nucleon is largest for weakly bound nucleons, depends on the bombarding energy (being largest for low-energy (slow) collisions) and produces a shift toward forward angle. Results of an adiabatic estimate employing two-center-shell-model wave functions in a DWBA amplitude are presented. A dynamical theory is sketched which involves a superposition of many transitions through excited bound and continuum states of the weakly bound nucleon. It is shown how the adiabatic amplitude emerges as the lowest approximation. 7 figures.
Date: August 1, 1977
Creator: Charlton, L.A.; Delic, G.; Glendenning, N.K. & Pruess, K.
Partner: UNT Libraries Government Documents Department
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Tritium migration studies at the Nevada Test Site

Description: Emanation of tritium from waste containers is a commonly known phenomenon. Release of tritium from buried waste packages was anticipated, therefore a research program was developed to study both the rate of tritium release from buried containers and subsequent migration of tritium through soil. Migration of tritium away from low level radioactive wastes buried in Area 5 of the Nevada Test Site was studied. Four distinct disposal events were investigated. The oldest burial event studied was a 1976 emplacement of 3.5 million curies of tritium in a shallow land burial trench. Tritium transport to the atmosphere by plant transpiration was determined to have risen sharply with the passage of time, and is now occurring at the rate of about 6 curies per year. The tritium being released from this waste has not resulted in elevated tritium levels in the urine of people working directly on the trench cap. Air samplers placed around the perimeter of the Area 5 site show no higher tritium levels than the Nevada Test Site in general. In another event, 248 thousand curies of tritium was disposed of in an overpack emplaced 6 meters below the floor of a low-level waste disposal pit. Measurement of the emanation rate of tritium out of 55 gallon drums to the overpack was studied, and an annual doubling of the emanation rate over a seven year period was found. No evidence of significant migration of tritium away from the overpack was found. In a third study, upward tritium migration in the soil was observed in a greater confinement disposal test. The movement was suspected largely to be the result of experimental anomalies and heat generated by other radionuclides present in the waste. Releases of tritium to the atmosphere were found to be insignificant. The fourth event consisted of burial of …
Date: August 1, 1991
Creator: Schulz, R. K.; Romney, E. M.; Fujii, L. M.; Greger, P. D.; Kendall, E. W. & Hunter, R.B. (Reynolds Electrical and Engineering Co., Inc., Las Vegas, NV (United States))
Partner: UNT Libraries Government Documents Department
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Calculation of the energy-dependent efficiency of gridded /sup 3/He fast-neutron ionization chambers

Description: Research and development activities under this contract proceeded along several lines, including development of a gas jet facility for the transport and isolation of fission product activities with half lives in the range T/sub 1/2/ less than or equal to 2 sec, studies on the factors affecting the energy and timing resolution of gridded /sup 3/He ionization detectors for delayed neutron spectroscopy and the development of simple models for calculation of the beta-decay characteristics of short-lived fission products near A = 90. Brief outlines of the activities in the areas are given. (WHK)
Date: February 9, 1982
Creator: Prussin, S.G.
Partner: UNT Libraries Government Documents Department
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Plasma theory and simulation research

Description: Our research group uses both theory and simulation as tools in order to increase the understanding of instabilities, heating, diffusion, transport and other phenomena in plasmas. We also work on the improvement of simulation, both theoretically and practically. Our focus has been more and more on the plasma edge (the sheath''), interactions with boundaries, leading to simulations of whole devices (someday a numerical tokamak).
Date: January 1, 1989
Creator: Birdsall, C.K.
Partner: UNT Libraries Government Documents Department
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(Medium energy meson research)

Description: In 1989, the research group's activities were divided into several components. The major activity was Experiment PS 197 at CERN-LEAR with the Crystal Barrel detector. This report will deal mainly with the results of our experiment to date and the future of the program at LEAR. The second effort was the completion of several projects which are in the data analysis and publication phase: muon-catalyzed fusion, which will be the thesis of Tom Case; muon decay {eta} parameter, the thesis of Roy Bossingham; and several other publications which are appearing or have appeared this year. The third area being pursued involves the KAON Factory at TRIUMF, where a working group on hadron spectroscopy has been formed. Responsibilities for program organization are shared by Ken Crowe and Martin Comyn of TRIUMF. In July 1990, a major meeting was held with this group. There was a week-long series of sessions reviewing the progress, updating the design and planning the program for both the periods before and after the final approval of KAON by the Canadian government.
Date: January 1, 1990
Partner: UNT Libraries Government Documents Department
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Analytical performance models for geologic repositories. Volume 2

Description: This report presents analytical solutions of the dissolution and hydrogeologic transport of radionuclides in geologic repositories. Numerical examples are presented to demonstrate the equations resulting from these analyses. The subjects treated in this report are: solubility-limited transport with transverse dispersion (chapter 2); transport of a radionuclide chain with nonequilibrium chemical reactions (chapter 3); advective transport in a two-dimensional flow field (chapter 4); radionuclide transport in fractured media (chapter 5); a mathematical model for EPA's analysis of generic repositories (chapter 6); and dissolution of radionuclides from solid waste (chapter 7). Volume 2 contains chapters 5, 6, and 7.
Date: October 1, 1982
Creator: Chambre, P. L.; Pigford, T. H.; Fujita, A.; Kanki, T.; Kobayashi, A.; Lung, H. et al.
Partner: UNT Libraries Government Documents Department
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Experimental studies of compact toroids

Description: The Berkeley Compact Toroid Experiment (BCTX) device is a plasma device with a Marshall-gun generated, low aspect ratio toroidal plasma. The device is capable of producing spheromak-type discharges and may, with some modification, produce low-aspect ratio tokamak configurations. A unique aspect of this experimenal devie is its large lower hybrid (LH) heating system, which consists of two 450MHz klystron tubes generating 20 megawatts each into a brambilla-type launching structure. Successful operation with one klystron at virtually full power (18 MW) has been accomplished with 110 {mu}s pulse length. A second klystron is currently installed in its socket and magnet but has not been added to the RF drive system. This report describes current activities and accomplishments and describes the anticipated results of next year's activity.
Date: January 1, 1991
Partner: UNT Libraries Government Documents Department
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Plasma confinement calculations for TIBER-II: Final report

Description: This paper compares the empirically based TIBER II design parameters against the reactor parameters of a tokamak based on a theoretical model of heat transport. The motivation behind this project is the following. The present TIBER-II design is based on an empirical scaling of confinement time tau/sub E/ known as Kaye-Goldston scaling. This empirical scaling is based on data from tokamak plasmas whose temperatures did not exceed a few keV, while the TIBER-II requires electron temperatures of 25 keV. The question, then, is whether the Kaye Goldston scaling is valid at temperatures above the range of empirical data. For this we must turn to theory. If a theoretical transport model is available that shows favorable correlation with the Kaye-Goldston scaling in the range of a few keV, then this scaling could be extrapolated to the 25 keV range required for TIBER-II. The project is divided into two parts. Part one of the project concerns the development of a transport model from plasma theory that has empirical support. Part two of the project consists of applying the transport model to the TIBER-II design. 8 refs., 3 tabs.
Date: October 14, 1987
Creator: Ibrahim, E.
Partner: UNT Libraries Government Documents Department
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Angular distributions of target fragments from the reactions of 292 MeV - 25. 2 GeV /sup 12/C with /sup 197/Au and /sup 238/U

Description: Angular distributions of target fragments from the reactions of /sup 12/C with /sup 197/Au and /sup 238/U were measured at projectile energies of 292 MeV, 1.0 GeV, 3.0 GeV, 12.0 GeV and 25.2 GeV. The angular distributions of the /sup 197/Au target fragments were all forwardly peaked. Extensively forward peaked angular distributions were observed at the non-relativistic projectile energies (292 MeV, 1.0 GeV). No obvious differences were observed in the angular distributions at the different relativistic projectile energies of 3.0 GeV, 12.0 GeV and 25.2 GeV. The characteristic angular distribution pattern from the relativistic projectile energy experiments was also observed in the non-relativistic energy experiments. Maximum degree of forward-peaking in the angular distributions at each projectile energy was observed at the product mass number (A) around 190 from the 292 MeV projectile energy, at A=180 from 1.0 GeV and at A=175 from 3.0 GeV and 12.0 GeV. In general, two different types of angular distributions were observed in the relativistic projectile energy experiments with the /sup 238/U target. Isotropic angular distributions were observed for the fission product nuclides. The angular distributions of the fission products at the intermediate (292 MeV) energy showed slightly forward- peaked angular distributions. Because of the long projectile-target interaction time in the primary nuclear reaction, larger momentum was transferred from the projectile to the target nucleus. Steep forward-peaked angular distributions were also observed with the /sup 238/U target.
Date: May 20, 1983
Creator: Morita, Y.
Partner: UNT Libraries Government Documents Department
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(Structure and stability of nucleic acids)

Description: We study the conformations of DNA and RNA oligonucleotides in order to understand their biological roles. We have determined the structure of the most common type of hairpin loop found in ribosomal RNA--the extra-stable tetraloop. It is actually a biloop with the other two bases in the loop forming a non-Watson-Crick base pair. This is the highest resolution structure reported for an RNA molecule in solution so far. We have obtained structures of pseudoknots and we have deduced general rules for their formation. We are presently studying a pseudoknot which is necessary for the replication of a retrovirus. The research done in the laboratory has been reported in 24 publications, plus 7 manuscripts in press or submitted. The research was done by 14 graduate students and 7 postdoctoral fellows. Five graduate students have received their Ph.D.s and 4 postdoctorals have finished their stay here. There are presently 9 graduate students and 3 postdoctorals working on the project; 2 new postdoctorals are expected this summer. One undergraduate student usually participates in the research during the year; this summer two undergraduates are working on the project. 31 refs., 4 figs.
Date: January 1, 1991
Creator: Tinoco, I. Jr.
Partner: UNT Libraries Government Documents Department
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First results from the Berkeley--Fermilab--Princeton multimuon spectrometer

Description: Muon interactions in a magnetized-steel calorimeter have produced 1000 +- 80 muons from J/psi(3100) decay, and 3 final states containing > 3 energetic muons. Use of proportional and drift chambers fully sensitive in the forward direction has resulted in uniform high acceptance for these processes, with 9% mass resolution. The psi photoproduction cross section continues to rise above 30 GeV, at a rate smaller than that predicted by a QCD calculation. Its Q/sup 2/-dependence fits (1 + Q/sup 2//M/sup 2/)/sup -2/ with M = 2.7 +- 0.5 GeV.
Date: May 1, 1979
Creator: Strovink, M.
Partner: UNT Libraries Government Documents Department
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Theoretical study of intermolecular energy transfer involving electronically excited molecules: He(/sup 1/S) + H/sub 2/(B /sup 1/. sigma. /sub u//sup +/). [Solution for coupled channel equations]

Description: To further understanding of gas phase collision dynamics involving electronically-excited molecules, a fully quantum mechanical study of He + H/sub 2/(B /sup 1/..sigma../sub u//sup +/) was undertaken. Iterative natural orbital configuration interaction (CI) calculations were performed to obtain the interaction potential between He and H/sub 2/(B /sup 1/..sigma../sub u//sup +/). The potential energy surface (PES) is highly anisotropic and has a van der Waals well of about 0.03 eV for C/sub 2v/ approach. Avoided PES crossings occur with He + H/sub 2/(E,F /sup 1/..sigma../sub g//sup +/) and with He + H/sub 2/(X /sup 1/..sigma../sub g//sup +/) and cause a local maximum and a deep minimum in the He + H/sub 2/(B /sup 1/..sigma../sub u//sup +/) PES, respectively. The crossing with He + H/sub 2/(X /sup 1/..sigma../sub g//sup +/) provides a mechanism for fluorescence quenching. The computed CI energies were combined with previous multi-reference double excitation CI calculations and fit with analytic functions for convenience in scattering calculations. Accurate dipole polarizabilities and quadrupole moment of H/sub 2/(B /sup 1/..sigma../sub u//sup +/) were computed for use in the multipole expansion, which is the analytic form of the long-range PES. 129 refs., 28 figs., 35 tabs.
Date: November 1, 1986
Creator: Grimes, R.M.
Partner: UNT Libraries Government Documents Department
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The Lamb shift in heliumlike uranium (U/sup 90 +/)

Description: An experimental value of 70.4 (8.3) eV for the one-electron Lamb shift in uranium is reported, in agreement with the theoretical value of 75.3 (0.4) eV. The Lamb shift is extracted from a beam-foil time-of-flight measurement of the 54.4 (3.4) ps lifetime of the 1s 2p/sub 1/2/ /sup 3/P/sub 0/ state of heliumlike (two-electron) uranium. 18 figs.
Date: January 1, 1987
Creator: Munger, C.T. Jr.
Partner: UNT Libraries Government Documents Department
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Development of nickel-free austenitic stainless steels for ambient and cryogenic applications

Description: A series of alloys have been developed as possible replacements for some austenitic stainless steels. These alloys utilized a Mn substitution for Ni and a reduced Cr concentration from the 18% ordinarily found in the AISI 300 series stainless steels to a concentration of 13%. The base system studied was an alloy containing Fe-16%Mn-13%Cr while other elements added included small additions of N, Si and Mo. A range of microstructures was produced from the alloying additions. The base composition had a triplex (fcc, hcp, bcc) structure while the most highly modified compositions were fully austenitic. Mechanical testing included tensile testing and Charpy V-notch testing conducted at various temperatures between -196/sup 0/C to 23/sup 0/C. Excellent combinations of strength and ductility were obtained (40--65 ksi yield strength, 100--125 ksi ultimate strength, 45--75% elongation and 60--80% reduction of area) at room temperature. Upper shelf energies in Charpy V-notch testing were as high as 185 ft-lbs with a ductile-brittle transition temperature (DBTT) of -160/sup 0/C. Analysis of fracture surfaces determined that alloys without interstitials had no transition in the mode of failure between room temperature and liquid nitrogen temperature. Results of an ASTM sensitization corrosion test, where the experimental alloys were compared to 347 stainless steel, indicated that the alloys were not susceptible to intergranular attack.
Date: February 1, 1978
Creator: Haddick, G. T.; Thompson, L. D.; Parker, E. R. & Zackay, V. F.
Partner: UNT Libraries Government Documents Department
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