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The multiplicity of shapes in Tl nuclei

Description: The results of experiments on rotational bands in light Tl nuclei are used to indicate the richness of shape phenomena in the vicinity of a closed proton shell. Rotational bands associated with normal prolate and oblate shapes as well as with a superdeformed shape are observed. 34 refs., 4 figs.
Date: December 1995
Creator: Riedinger, L. L.; Reviol, W. & Lewis, J. M.
Partner: UNT Libraries Government Documents Department

The Knock-Limited Performance of S Reference Fuel Plus 2 Milliliters of Triethylthallium Per Gallon

Description: Report discusses the results of testing of thallium as an antiknock agent in an internal-combustion engine. From Introduction: "On a weight basis, the thallium vapors were found to have several times the antiknock value of tetraethyl lead, which was added to the fuel. The amount of thallium vapor necessary to raise the antiknock properties of a gasoline up to exact equivalence with a benzol-gasoline mixture was determined in these engine tests."
Date: November 1945
Creator: Meyer, Carl L.
Partner: UNT Libraries Government Documents Department

Superdeformed shapes and configurations in thallium nuclei

Description: Superdeformation studies in {sup 189,191,192}Tl at Gammasphere are discussed. New results on {sup 191}Tl are the observation of interband transitions between the signature partner E2 bands and the measurement of an average quadrupole moment (Q{sub 0} = 18 {+-} 1 eb) for these superdeformed structures. These data enable them to derive absolute M1 strengths and confirm that the 81st proton occupies the [642]5/2 orbital. Tentative data for one superdeformed sequence in {sup 189}Tl are consistent with the prediction of a decrease in quadrupole deformation for the lightest nuclei at the limit of this island of superdeformation.
Date: September 1997
Creator: Reviol, W.; Mueller, W. F. & Riedinger, L. L.
Partner: UNT Libraries Government Documents Department

Cathodic Vacuum Arc Plasma of Thallium

Description: Thallium arc plasma was investigated in a vacuum arc ionsource. As expected from previous consideration of cathode materials inthe Periodic Table of the Elements, thallium plasma shows lead-likebehavior. Its mean ion charge state exceeds 2.0 immediately after arctriggering, reaches the predicted 1.60 and 1.45 after about 100 microsecand 150 microsec, respectively. The most likely ion velocity is initially8000 m/s and decays to 6500 m/s and 6200 m/s after 100 microsec and 150microsec, respectively. Both ion charge states and ion velocities decayfurther towards steady state values, which are not reached within the 300microsec pulses used here. It is argued that the exceptionally high vaporpressure and charge exchange reactions are associated with theestablishment of steady state ion values.
Date: October 2, 2006
Creator: Yushkov, Georgy Yu. & Anders, Andre
Partner: UNT Libraries Government Documents Department

Some Nuclear Properties of Bi206, Tl200, Tl201, Tl202, In109, In110m, and In111 : the Nuclear Spins of Bi206, Tl200, Tl201, and Tl202 ; the Nuclear Spins, Magnetic Dipole, and Electric Quadrapole Interaction Constants of In209, In110m, and In111 (thesis)

Description: The atomic-beam magnetic-resonance flop-in technique using radioactive detection was employed to measure the nuclear spins doff B/sup 206/ , Ti/sup 200/ , Tl/sup 201/ Tl/sup 202, In/sup 09. ln/sup 110m/ and In/sup 111/. In addition the magnetic-dipole and constatns of In/sup 109/, In/sup 110m/, ined. the signs of the In/sup 110m/ con-, stants were not determined. Results, theory, procedure, and data reduction are given. (auth)
Date: April 1, 1959
Creator: Marino, L. L.
Partner: UNT Libraries Government Documents Department

Systematic description of superdeformed bands in the Mass-190 region

Description: Superdeformed bands for the mass-190 region are described by the Projected Shell Model. Even-even, odd mass and odd-odd nuclei are equally well described. Good agreement with available data for all isotopes studied is obtained. Our,calculation of electromagnetic properties and pairing correlations provides an understanding of the observed gradual increase of dynamical moments of inertia with angular momentum observed in many bands in this mass region.
Date: December 31, 1996
Creator: Sun, Y.; Guidry, M. & Zhang, J.
Partner: UNT Libraries Government Documents Department

Design of a System for the Nondestructive Assay of {sup 233}U in Waste Drums

Description: A system for the nondestructive assay of waste drums containing {sup 233}U has been installed in Bldg. 3019. This system employs two 3 x 3 in. NaI scintillation detectors, and standard counting techniques and analyses of the 2.6-MeV gamma radiation emitted by {sup 208}Tl. Thallium-208 is a product of the decay of {sup 232}U, which is usually present as an impurity in {sup 233}U. Results show that the system is capable of determining gram quantities of {sup 233}U in a 55-gal rotating drum. Standard deviations of the results are also reported.
Date: May 18, 2001
Creator: DeCarlo, V.A.
Partner: UNT Libraries Government Documents Department

Department of Energy`s Wire Development Workshop - Superconductivity program for electric systems

Description: The 1996 High-Temperature Superconducting Wire Development Workshop was held on January 31--February 1 at the Crown Plaza Tampa Westshore in Tampa, Florida. The meeting was hosted by Tampa Electric Company and sponsored by the Department of Energy`s Superconductivity Program for Electric Systems. The meeting focused on recent high-temperature superconducting wire development activities in the Department of Energy`s Superconductivity Systems program. Tampa Electric`s Greg Ramon began the meeting by giving a perspective on the changes now occurring in the utility sector. Major program wire development accomplishments during the past year were then highlighted, particularly the world record achievements at Los Alamos and Oak Ridge National Laboratories. The meeting then focussed on three priority technical issues: thallium conductors; AC losses in HTS conductors; and coated conductors on textured substrates. Following in-depth presentations, working groups were formed in each technology area to discuss and critique the most important current research and development issues. The working groups identified research areas that have the potential for greatly enhancing the wire development effort. These areas are discussed in the summary reports from each of the working groups. This document is a compilation of the workshop proceedings including all general session presentations and summary reports from the working groups.
Date: June 1, 1996
Partner: UNT Libraries Government Documents Department

The Spectroscopy of {sup 183}Tl: An Extreme Case of Prolate-Oblate Shape-Competition

Description: The yrast sequence in {sup 183}Tl has been studied for the first time in recoil-mass and decay tagged gamma-ray spectroscopic measurements. A rotational-like cascade of seven transitions is observed down to the bandhead with spin 13/2+. In contrast to adjacent nuclei, links from the yrast band to a lower lying weakly deformed (oblate) structure are not observed. It appears that the prolate energy minimum in {sup 183}Tl drops significantly compared to {sup 185}Tl and minimizes below the neutron i13/2 midshell (n <= 102). Possibilities for the decay out of the band in {sup 183}Tl are discussed.
Date: August 10, 1998
Creator: Batchelder, J.C.; Bingham, C.R.; Carpenter, M.P.; Cizewski, J.A.; Gross, C.J.; Helariutta, K. et al.
Partner: UNT Libraries Government Documents Department

{sup 203,205}Tl NMR Studies of Crystallographically Characterized Thallium Alkoxides. X-Ray Structures of [Tl(OCH{sub 2}CH{sub 3})]4 and [Tl(OAr)]{sub infinity} where OAr = OC{sub 6}H{sub 3}(Me){sub 2}-2,6 and OC{sub 6}H{sub 3}(Pr{sup i}){sub 2}-2,6

Description: [Tl(OCH{sub 2}CH{sub 3})]{sub 4}, (1) was reacted with excess HOR to prepare a series of [Tl(OR)]{sub n} where OR= OCHMe{sub 2} (2, n = 4), OCMe{sub 3} (3, n = 4), OCH{sub 2}CMe{sub 3} (4, n = 4), OC{sub 6}H{sub 3}(Me){sub 2}-2,6 (5, n = {infinity}), and OC{sub 6}H{sub 3}(Pr{sup i}){sub 2}-2,6 (6, n = {infinity}). Single crystal X-ray diffraction was used to determine the structure of compounds ligated by more sterically demanding ligands. Compound 4 was found to adopt a cubane structure, while 5 and 6 formed linear polymeric structures. These compounds were additionally characterized by {sup 203,205}Tl solution and {sup 205}Tl solid state NMR. Compounds 1--4 were found to remain intact in solution while the polymeric species, 5 and 6, appeared to be fluxional. While variations in the solution and solid state structures for the tetrameric [Tl(OR)]{sub 4} and polymeric [Tl(OAr)]{sub {infinity}} may be influenced by the steric hindrance of their respective ligands, the covalency of the species is believed to be more an effect of the parent alcohol acidity.
Date: July 25, 2000
Creator: ZECHMANN,CECILIA A.; BOYLE,TIMOTHY J.; PEDROTTY,DAWN M.; ALAM,TODD M.; LANG,DAVID P. & SCOTT,BRIAN L.
Partner: UNT Libraries Government Documents Department

Processing of Mo-Si-B intermetallics by extrusion and oxidation properties of the extruded Tl-MoSi{sub 2}-MoB System

Description: An extrusion process was developed that is able to consistently produce large quantities of Mo-Si-B rods without the presence of defects. Binder removal from the extruded rods was studied in detail and it was determined that heating rates on the order of 0.02{degree}/minute (1.2{degree}/hour) are necessary to remove the binder without the formation of defects. This low heating rate resulted in debinding times in excess of 70 hours (approximately 3 days). Wicking was investigated as a means to decrease the time necessary for binder removal. Using 0.05{micro}m alumina powder as a wicking agent, binder removal times were reduced to 10 hours with heating rates up to 1{degree}/minute employed without defect formation. Once the extrusion process was complete the oxidation properties of the Tl-MoSi{sub 2}-MoB extruded phase assemblage was investigated. It was determined that this composition exhibits catastrophic oxidation or pesting in the temperature range of 660--760 C, resulting in the material turning to dust. Outside of this temperature range the composition is oxidatively stable. Continuous mass measurements were taken at 1,300, 1,450, and 1,600 C to determine the oxidation rate constants of this material. Parabolic rate constants of 6.9 x 10{sup {minus}3}, 1.3 x 10{sup {minus}3}, and 9.1 x 10{sup {minus}3} mg{sup 2}/cm{sup 4}/hr were determined for 1,300, 1,450, and 1,600 C respectively.
Date: November 8, 1999
Creator: Summers, Eric
Partner: UNT Libraries Government Documents Department

Paths for current flow in polycrystalline high temperature superconductors

Description: Determinations from x-ray and electron microdiffraction studies of the populations and geometrical arrangements of small angle grain boundaries in Bi-2223 and Bi-2212 conductors and Tl-1223 deposits suggest that current flow in these polycrystalline materials is percolative in character. Comparison of measured misorientation angle distributions to calculated distributions suggest that not only texture but also grain boundary energy is important in increasing the number of small angle grain boundaries.
Date: December 1995
Creator: Kroeger, D. M.; Goyal, A. & Specht, E. D.
Partner: UNT Libraries Government Documents Department

Atomic structure of active sites in O{sub 2} reduction on Au(111)/Tl{sub ad} electrodes in acid and alkaline solutions

Description: Surface x-ray scattering has been used to determine the structure of Tl adlayers on the Au(111) electrode surface during the course of 0{sub 2} reduction. 0. reduction is considerably catalyzed by Ti adlayers on Au(111). The half-wave potential is shifted to more positive values in the presence of the Ti adlayer. In both, acid and alkaline solutions TI causes a change in the reaction mechanism from a 2-ereduction to a 4e-reduction in a limited potential range. The in-plane X-ray diffraction measurements revealed that the close-packed rotated-hexagonal Ti phase, which exists in the potential range between -0.4V and the bulk TI deposition at {approx}{minus} 0.7V, has a lower activity for 0. reduction than the low-coverage phases in both solutions. It supports a 2e-reduction.0{sub 2} reduction does not change the TI coverage in this phase but causes a significant decrease of the in-plane diffracted intensity. The lower coverage phases which exist at more positive potentials, viz., aligned hexagonal in alkaline solution and patches of the (2 {times} 2)TI phase in acid solution, are conducive to a 4e-reduction. The diffraction intensity from these two phases, however, vanishes quickly during O{sub 2} reduction. It appears that the TI coverage remains on the surface unchanged. These observations indicate that the O{sub 2} molecules interact directly with the Tl adatoms prior to the charge transfer. This provides the most direct evidence that the outer sphere charge transfer mechanism in 0{sub 2} reduction is not operative for some surfaces. H{sub 2}0{sub 2} reduction is facile on the surface covered with the low-coverage TI phases, while it is almost completely suppressed by the rotated-hexagonal phase.
Date: December 31, 1995
Creator: Adzic, R.R. & Wang, J.X.
Partner: UNT Libraries Government Documents Department

Experimental test of nuclear magnetization distribution and nuclear structure models

Description: Models exist that ascribe the nuclear magnetic fields to the presence of a single nucleon whose spin is not neutralized by pairing it up with that of another nucleon; other models assume that the generation of the magnetic field is shared among some or all nucleons throughout the nucleus. All models predict the same magnetic field external to the nucleus since this is an anchor provided by experiments. The models differ, however, in their predictions of the magnetic field arrangement within the nucleus for which no data exist. The only way to distinguish which model gives the correct description of the nucleus would be to use a probe inserted into the nucleus. The goal of our project was to develop exactly such a probe and to use it to measure fundamental nuclear quantities that have eluded experimental scrutiny. The need for accurately knowing such quantities extends far beyond nuclear physics and has ramifications in parity violation experiments on atomic traps and the testing of the standard model in elementary particle physics. Unlike scattering experiments that employ streams of free particles, our technique to probe the internal magnetic field distribution of the nucleus rests on using a single bound electron. Quantum mechanics shows that an electron in the innermost orbital surrounding the nucleus constantly dives into the nucleus and thus samples the fields that exist inside. This sampling of the nucleus usually results in only minute shifts in the electron´┐Ż s average orbital, which would be difficult to detect. By studying two particular energy states of the electron, we can, however, dramatically enhance the effects of the distribution of the magnetic fields in the nucleus. In fact about 2% of the energy difference between the two states, dubbed the hyperfine splitting, is determined by the effects related to the distribution of ...
Date: February 26, 1999
Creator: Beirsdorfer, P; Crespo-Lopez-Urrutia, J R & Utter, S B
Partner: UNT Libraries Government Documents Department

Measurement of the Electron Affinities of Indium and Thallium

Description: The electron affinities of indium and thallium were measured in separate experiments using the laser-photodetachment electron spectroscopy technique. The measurements were performed at the University of Nevada, Reno. Negative ion beams of both indium and thallium were extracted from a cesium-sputter negative ion source, and mass analyzed using a 90{sup o} bending magnet. The negative ion beam of interest was then crossed at 90{sup o} with a photon beam from a cw 25-Watt Ar{sup +} laser. The resulting photoelectrons were energy analyzed with a 160{sup o} spherical-sector spectrometer. The electron affinity of In({sup 2}P{sub 1/2}) was determined to be 0.404 {+-} 0.009 eV and the electron affinity of thallium was determined to be 0.377 {+-} 0.013 eV. The fine-structure splittings in the ground states of the negative ions were also determined. The experimental measurements will be compared to several recent theoretical predictions.
Date: March 20, 1999
Creator: Thompson, J. S.; Carpenter, D. L.; Covington, A. M.; Williams, W. W.; Kvale, T. J. & Seely, D. G.
Partner: UNT Libraries Government Documents Department

LABORATORY INVESTIGATIONS IN SUPPORT OF FLUID-BED FLUORIDE VOLATILITY PROCESSES. PART II. THE PROPERTIES OF PLUTONIUM HEXAFLUORIDE

Description: All of the properties of plutonium hexfluoride reported up to May 1983 are summarized, andd pentinent data are presented in detail. Included are the preparation of plutonium hexafluoride, physical properties, absorption spectra, chemical reactions, decomposition of plutonium hexafluoride by radiation and heat, the corrosion of materials of construction by plutonium hexafluoride, and a summary of the biological and radiological hazards from plutonium hexafluoride. An expanded vapor pressure table is appended. 122 references are included. (auth)
Date: August 1, 1963
Creator: Steindler, M.J.
Partner: UNT Libraries Government Documents Department

New results on superdeformed bands in Hg and Tl nuclei

Description: New results have been obtained on superdeformed states in {sup 190}Hg, {sup 191}Tl, and {sup 192}Tl. For {sup 190}Hg, the previously identified superdeformed band has been extended up to a rotational frequency of {Dirac_h}{omega} {ge} 0.40 MeV by combining data from several different experiments. The extracted dynamical moment of inertia J({sup 2}) vs {Dirac_h}{omega} exhibits a distinct change in slope at {Dirac_h}{omega} = 0.32 MeV. For {sup 191}Tl and {sup 192}Tl, two and six superdeformed bands have been identified in these nuclei, respectively. Six of these eight bands exhibit a smooth rise in J({sup 2}) with {Dirac_h}{omega} characteristic of the other superdeformed bands identified in this mass region while the remaining two bands which are in {sup 192}Tl show a constant J({sup 2}) with {Dirac_h}{omega}. This new result can be understood in terms of Pauli blocking of quasiparticle alignments in high-N intruder orbitals. The new result for {sup 190}Hg is interpreted as evidence of a band interaction at the highest frequencies due to the rotational alignment of a pair of quasiparticles into these same intruder orbitals. These two new features taken together represent the first conclusive evidence that the alignment of intruders is responsible for the smooth rise in J({sup 2}) seen in the other superdeformed bands of this mass region.
Date: December 31, 1992
Creator: Carpenter, M. P.; Janssens, R. V. F.; Liang, Y.; Ahmad, I.; Henry, R. G.; Khoo, T. L. et al.
Partner: UNT Libraries Government Documents Department

HIGH INTENSITY LIGHT SOURCES (Part II of Thesis)

Description: A stable carbon arc operated in controlled atmosphere is described. The arc was designed to serve as a light source during lifetime studies of the B/sup 2/ SIGMA state of the CN molecule. The CN radiation from the plasma of the arc was investigated and found to have a brightness temperature of 5500 icient laborato K at lambda 3883 A. This is considerably higher than an estimate of the value required for lifetime measurements. The stability of the carbon arc under various conditions is discussed. For successful lifetime measurements, the light source employed must have a high brightness temperature (intensity). A method for the determination of the brightness temperature of a light source at a specific wave length is described. The method was used for determining the brightness temperatures of some available light sources. Sodium, thallium, and mercury discharge lamps, a medium-pressure mercury arc lamp, and the carbon arc were studied. (auth)
Date: October 1, 1958
Creator: Worden, E.F. Jr.
Partner: UNT Libraries Government Documents Department