Resource Type

User needs: is a survey the answer (open access)

User needs: is a survey the answer

Some of the ramifications of user needs, user satisfaction, and the survey as a shaper of library policy are discussed. The presentation is in three parts: philosophical thinking on user needs and satisfaction, a modest tutorial on survey methodology, and a brief review of the Sandia National Laboratory Technical Library's use of surveys for information gathering and decision making. (RWR)
Date: January 1, 1980
Creator: Gardner, J.L.
System: The UNT Digital Library
Formaldehyde Absorption toward W51 (open access)

Formaldehyde Absorption toward W51

We have measured formaldehyde (H{sub 2}CO) absorption toward the HII region complex W51A (G49.5-0.4) in the 6 cm and 2 cm wavelength rotational transitions with angular resolution of approximately 4 inch. The continuum HII region shows a large, previously undetected shell structure 5.5 pc along the major axis. We observe no H{sub 2}CO emission in regions of low continuum intensity. The absorption, converted to optical depth, shows a higher degree of clumping than previous maps at lower resolution. The good S/N of the maps allows accurate estimation of the complicated line profiles, showing some of the absorbing clouds to be quite patchy. We list the properties of the opacity spectra for a number of positions both in the clumps and in the more diffuse regions of the absorbing clouds, and derive column densities for the 1{sub 11} and 2{sub 12} rotational levels of ortho-formaldehyde.
Date: April 1, 1988
Creator: Kogut, A.; Smoot, G. F.; Bennett, C. L. & Petuchowski, S. J.
System: The UNT Digital Library
Parallel algorithm for transient solid dynamics simulations using finite elements and smoothed particle hydrodynamics (open access)

Parallel algorithm for transient solid dynamics simulations using finite elements and smoothed particle hydrodynamics

An efficient, scalable, parallel algorithm for treating contacts in solid mechanics has been applied to interactions between particles in smooth particle hydrodynamics (SPH). The algorithm uses three different decompositions within a single timestep: (1) a static FE-decomposition of mesh elements; (2) a dynamic SPH-decomposition of SPH particles; (3) and a dynamic contact-decomposition of contact nodes and SPH particles. The overhead cost of such a scheme is the cost of moving mesh and particle data between the decompositions. This cost turns out to be small in practice, leading to a highly load-balanced decomposition in which to perform each of the three major computational states within a timestep.
Date: May 1, 1997
Creator: Attaway, S. W.; Hendrickson, B. A.; Plimpton, S. J.; Swegle, J. W.; Gardner, D. R. & Vaughan, C. T.
System: The UNT Digital Library
Reaction cross-section calculations using new experimental and theoretical level structure data for deformed nuclei (open access)

Reaction cross-section calculations using new experimental and theoretical level structure data for deformed nuclei

A technique for modeling level structures of odd-odd nuclei has been used to construct sets of discrete states with energies in the range 0 to 1.5 MeV for several nuclei in the rare-earth and actinide regions. The accuracy of the modeling technique was determined by comparison with experimental data. Examination was made of what effect the use of these new, more complete sets of discrete states has on the calculation of level densities, total reaction cross sections, and isomer ratios. 9 refs.
Date: May 1, 1985
Creator: Hoff, R. W.; Gardner, D. G. & Gardner, M. A.
System: The UNT Digital Library
Experimental database and design concept for a 1-MW, 200-keV neutral-beam line based on a SITEX negative ion source (open access)

Experimental database and design concept for a 1-MW, 200-keV neutral-beam line based on a SITEX negative ion source

Scaling studies for a SITEX negative ion source to produce 200-keV, 10-A, long pulse D/sup -/ beams are under way at Oak Ridge National Laboratory (ORNL). Designs have been restricted to the use of established techniques and reasonably well-demonstrated scaling. The results show that the 1-A SITEX source can be directly scaled to produce 200-keV, 10-A long pulse ion beams with a source power efficiency of less than or equal to 5 kW of total plasma generator power per ampere of D/sup -/ beam generated. Extracted electron-to-D/sup -/ ratios should be less than or equal to 0.06, with all extracted electrons recovered at less than or equal to 10% of the first gap potential energy difference. The close-coupled accelerating structure will be 5 cm long and have five electrodes with 21 slits each, with a 50-kV/cm field in each gap.
Date: January 1, 1983
Creator: Dagenhart, W. K.; Gardner, W. L.; Stirling, W. L. & Whealton, J. H.
System: The UNT Digital Library
Electrode design and performance of the ORNL positive ion sources (open access)

Electrode design and performance of the ORNL positive ion sources

The neutral beam development group at ORNL has designed, constructed, and shipped four 50-kV, 100-A sources to PPPL to be used for neutral beam heating of the confined plasma on the PDX tokamak. These sources have higher current capability than scaled-down sources, and they are required to run for 0.5 s as opposed to the 0.3-s requirement for PLT and ISX-B sources. Due to an innovative electrode design, these higher power sources met these requirements and achieved a higher transmission efficiency - 76% of the total input power on target vs 60% for the original ISX-B and modified PLT sources or 40% for the original PLT sources. As a consequence, a power of 2 MW of neutrals to the torus target was achieved; this is a record for measured neutral power and exceeds that of any other power source expected to be used on such advanced tokamaks as TFTR and D-III. A theoretical consideration of the relevant Poisson-Vlasov equations for ions extracted from a plasma was used to optimize the ion optics. Using the same electrode design with a tetraode accelerating structure and a new, indirectly heated cathode, repeatable long pulse, high energy conditions of 70 kV, 7 A, 8 …
Date: January 1, 1980
Creator: Whealton, J.H.; Gardner, W.L. & Haselton, H.H.
System: The UNT Digital Library
Micromechanical modeling of damage and inelasticity of composite materials in macroscopic structural analysis (open access)

Micromechanical modeling of damage and inelasticity of composite materials in macroscopic structural analysis

The method of cells has been extended to include damage or debonding between all adjacent subcells using a finite element formulation for the original cells assembly. Damage is implemented by placing a nonlinear three-dimensional spring between adjacent subcells. With this arrangement the damage is inherently anisotropic. The ``nonlinear substructure`` cells finite element model is incorporated as a user defined material routine in a general purpose finite element code. The primary motivation for casting the method of cells as a finite element assemblage is to provide a composite constitutive model that facilitates the incorporation of various constituent material models, as well as any level of detail desired in the microstructure geometry. At present, the constituent material models may be anisotropic elastic or isotropic viscoelastic-plastic, while damage evolution is based on the macroscopic strain. The capability of the model is demonstrated through analyses of some simple structures loaded to failure.
Date: December 1, 1994
Creator: Macek, R. W.; Gardner, J. P. & Hackett, R. M.
System: The UNT Digital Library
Some tools of the trade we`ve developed for our cross-section calculations (open access)

Some tools of the trade we`ve developed for our cross-section calculations

A number of compute codes have been modified or developed, both main-frame and PC. Seven codes, of which three are discussed in some detail. The later are: a controller-driven, double-precision version of the coupled-channel code ECIS; the latest version of STAPRE, a precompound plus Hauser-Feshbach nuclear reaction code; and NUSTART, a PC code that analyzes large sets of discrete nuclear levels and the multipole transitions among them. All main-frame codes are now being converted to the UNICOS operating system.
Date: November 1, 1992
Creator: Gardner, D. G. & Gardner, M. A.
System: The UNT Digital Library
Calculated neutron capture cross sections for the ground states and isomers of /sup 93/ /sup 94/ and /sup 95/Nb. [Resolved resonance region to 4 MeV, strength functions, statistical model] (open access)

Calculated neutron capture cross sections for the ground states and isomers of /sup 93/ /sup 94/ and /sup 95/Nb. [Resolved resonance region to 4 MeV, strength functions, statistical model]

Neutron-induced capture cross sections for the ground states and first isomeric states of /sup 93/Nb, /sup 94/Nb and /sup 95/Nb were studied from the resolved resonance region to 4 MeV via statistical model calculations. The production of isomers was included. Inelastic scattering cross sections and gamma-ray production spectra were also calculated. The anti GAMMA/ sub ..gamma..//D ratios were derived from gamma-ray strength function systematics. Total capture cross sections on the ground states are found to be within a factor of two of each other. Capture cross sections on the isomeric targets are important as well, not only because of their magnitude but also because of the significant population of these isomeric levels by inelastic scattering. 10 references.
Date: September 1, 1978
Creator: Gardner, M. A. & Gardner, D. G.
System: The UNT Digital Library
ORNL 150 keV neutral beam test facility (open access)

ORNL 150 keV neutral beam test facility

The 150 keV neutral beam test facility provides for the testing and development of neutral beam injectors and beam systems of the class that will be needed for the Tokamak Fusion Test Reactor (TFTR) and The Next Step (TNS). The test facility can simulate a complete beam line injection system and can provide a wide range of experimental operating conditions. Herein is offered a general description of the facility's capabilities and a discussion of present system performance.
Date: January 1, 1977
Creator: Gardner, W.L.; Kim, J.; Menon, M.M. & Schilling, G.
System: The UNT Digital Library
Search for W-prime boson production in the top quark decay channel (open access)

Search for W-prime boson production in the top quark decay channel

We present a search for the production of a new heavy gauge boson W' that decays to a top quark and a bottom quark. We have analyzed 230 pb{sup -1} of data collected with the D0 detector at the Fermilab Tevatron collider at a center-of-mass energy of 1.96 TeV. No significant excess of events is found in any region of the final state invariant mass distribution. We set upper limits on the production cross section of W bosons at the 95% confidence level for several different W' boson masses. We exclude masses below 610 GeV for a W' boson with standard-model-like couplings, below 630 GeV for a W' boson with right-handed couplings that is allowed to decay to both leptons and quarks, and below 670 GeV for a W' boson with right-handed couplings that is only allowed to decay to quarks.
Date: July 1, 2006
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
System: The UNT Digital Library
Pulsed laser stereo photography of electrically exploded bridges (open access)

Pulsed laser stereo photography of electrically exploded bridges

A technique is described for obtaining short exposure (approximately 8 ns) high resolution photomicrographs of electrically exploded bridges using a pulsed laser for bridge illumination and band-pass filters to eliminate the intense self light. Two cameras are described, one for a small field of view (approximately 1 mm) and one for a relatively large field of view (approximately 20 mm). A carbon disulfide cell and a fiber-optic light guide are used to essentially eliminate speckle, which normally limits the resolution of laser photographs of diffuse surfaces. A series of photomicrographs showing the detailed burst characteristics of both flat and round bridges are shown.
Date: January 1, 1976
Creator: Seitz, W. L. & Gardner, S. D.
System: The UNT Digital Library
Search for right-handed W bosons in top quark decay (open access)

Search for right-handed W bosons in top quark decay

None
Date: May 1, 2005
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
System: The UNT Digital Library
A Search for anomalous heavy-flavor quark production in association with W bosons (open access)

A Search for anomalous heavy-flavor quark production in association with W bosons

None
Date: November 1, 2004
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
System: The UNT Digital Library
Indium donor complexes with cation vacancies in CdTe and ZnSe (open access)

Indium donor complexes with cation vacancies in CdTe and ZnSe

Very dilute (10{sub 12} cm{sup {minus}3}) indium donors in CdTe and ZnSe powders and in CdTe single crystals were investigated using {sup 111}In Perturbed angular correlation spectroscopy. Most indium atoms are in uncomplexed sites but can form weakly-bound complexes with native defects in very defective material. The only complex observed in CdTe is an indium-Cd vacancy pair. The CdTe in which these pairs occur is apparently n-type, most Cd vacancies are free and doubly-charged, and the binding energy with indium is 0.15 eV. In ZnSe, indium can pair with a Zn vacancy or with some other presently unidentified defect. These complexes form in ZnSe containing large concentrations of both free Zn vacancies and complexes of Zn vacancies with other defects. In CdTe, the pair formation equilibration time constant is two days at 15C,an implication that Cd vacancies are mobile at room temperature. Lattice relaxation around a Cd vacancy in CdTe was probed by single crystal PAC experiments.
Date: November 1, 1993
Creator: Griffith, J. W.; Lundquist, R.; Platzer, R.; Gardner, J. A.; Karczewski, G. & Furdyna, J. K.
System: The UNT Digital Library
Methods and procedures for evaluation of neutron-induced activation cross sections (open access)

Methods and procedures for evaluation of neutron-induced activation cross sections

One cannot expect measurements alone to supply all of the neutron-induced activation cross-section data required by the fission reactor, fusion reactor, and nuclear weapons development communities, given the wide ranges of incident neutron energies, the great variety of possible reaction types leading to activation, and targets both stable and unstable. Therefore, the evaluator must look to nuclear model calculations and systematics to aid in fulfilling these cross-section data needs. This review presents some of the recent developments and improvements in the prediction of neutron activation cross sections, with specific emphasis on the use of empirical and semiempirical methods. Since such systematics require much less nuclear informaion as input and much less computational time than do the multistep Hauser-Feshbach codes, they can often provide certain cross-section data at a sufficient level of accuracy within a minimum amount of time. The cross-section information that these systematics can and cannot provide and those cases in which they can be used most reliably are discussed.
Date: September 1, 1981
Creator: Gardner, M.A.
System: The UNT Digital Library
Thin film porous membranes for catalytic sensors (open access)

Thin film porous membranes for catalytic sensors

This paper reports on new and surprising experimental data for catalytic film gas sensing resistors coated with nanoporous sol-gel films to impart selectivity and durability to the sensor structure. This work is the result of attempts to build selectivity and reactivity to the surface of a sensor by modifying it with a series of sol-gel layers. The initial sol-gel SiO{sub 2} layer applied to the sensor surprisingly showed enhanced O{sub 2} interaction with H{sub 2} and reduced susceptibility to poisons such as H{sub 2}S.
Date: June 1, 1997
Creator: Hughes, R.C.; Boyle, T.J. & Gardner, T.J.
System: The UNT Digital Library
Development of a thermoacoustic natural gas liquefier. (open access)

Development of a thermoacoustic natural gas liquefier.

Praxair, in conjunction with the Los Alamos National Laboratory, is developing a new technology, thermoacoustic heat engines and refrigerators, for liquefaction of natural gas. This is the only technology capable of producing refrigeration power at cryogenic temperatures with no moving parts. A prototype, with a projected natural gas liquefaction capacity of 500 gallons/day, has been built and tested. The power source is a natural gas burner. Systems will be developed with liquefaction capacities up to 10,000 to 20,000 gallons per day. The technology, the development project, accomplishments and applications are discussed. In February 2001 Praxair, Inc. purchased the acoustic heat engine and refrigeration development program from Chart Industries. Chart (formerly Cryenco, which Chart purchased in 1997) and Los Alamos had been working on the technology development program since 1994. The purchase included assets and intellectual property rights for thermoacoustically driven orifice pulse tube refrigerators (TADOPTR), a new and revolutionary Thermoacoustic Stirling Heat Engine (TASHE) technology, aspects of Orifice Pulse Tube Refrigeration (OPTR) and linear motor compressors as OPTR drivers. Praxair, in cooperation with Los Alamos National Laboratory (LANL), the licensor of the TADOPTR and TASHE patents, is continuing the development of TASHE-OPTR natural gas powered, natural gas liquefiers. The liquefaction …
Date: January 1, 2002
Creator: Wollan, John J.; Swift, Gregory W.; Backhaus, Scott N. & Gardner, David L.
System: The UNT Digital Library
Spectral shaping and phase control of a fast-wave current drive antenna array (open access)

Spectral shaping and phase control of a fast-wave current drive antenna array

The requirements for antenna design and phase control circuitry for a fast-wave current drive (FWCD) array operating in the ion cyclotron range of frequencies are considered. The design of a phase control system that can operate at arbitrary phasing over a wide range of plasma-loading and strap-coupling values is presented for a four-loop antenna array, prototypical of an array planned for the DIII-D tokamak (General Atomics, San Diego, California). The goal is to maximize the power launched with the proper polarization for current drive while maintaining external control of phase. Since it is desirable to demonstrate the feasibility of FWCD prior to ITER, a four-strap array has been designed for DIII-D to operate with the existing 2-MW transmitter at 60 MHz. 3 refs., 6 figs.
Date: January 1, 1989
Creator: Baity, F. W.; Gardner, W. L.; Goulding, R. H.; Hoffman, D. J. & Ryan, P. M.
System: The UNT Digital Library
History and results of VC-1, the first CSDP corehole in Valles caldera, New Mexico (open access)

History and results of VC-1, the first CSDP corehole in Valles caldera, New Mexico

Valles Caldera No. 1 (VC-1) is the first Continental Scientific Drilling Program (CSDP) corehole drilled in the Valles caldera and the first continuously cored hole in the caldera region. The objectives of VC-1 were to penetrate a hydrothermal outflow plume near its source, to obtain structural and stratigraphic information near the intersection of the ring-fracture zone and the pre-caldera Jemez fault zone, and to core the youngest volcanic unit inside the caldera (Banco Bonito obsidian, 0.13 Ma). VC-1 penetrates 298 m of moat volcanics and caldera-fill ignimbrites, 35 m of pre-caldera volcaniclastic breccia, and 523 m of Paleozoic carbonates, sandstones and shales, with over 95% core recovery. Hydrothermal alterations are concentrated in sheared, brecciated and fractured zones from the volcaniclastic breccia to total depth with both the intensity and rank of alterations increasing with depth. Alterations consist primarily of clays, calcite, pyrite, quartz, and chlorite, but chalcopyrite has been identified as high as 518 m and molybdenite has been identified in a fractured zone at 847 m. Thermal aquifers were penetrated at various intervals from about 510 m on down. 11 refs., 5 figs.
Date: January 1, 1985
Creator: Goff, F.; Rowley, J.; Gardner, J.N.; Hawkins, W.; Goff, S.; Pisto, L. et al.
System: The UNT Digital Library
Structural safety features for superconducting magnets (open access)

Structural safety features for superconducting magnets

A survey has been carried out for various potential structural safety problems of superconducting fusion magnets. These areas include: (1) Stresses due to inhomogeneous temperature distributions in magnets where normal regions have been initiated. (2) Stress distributions and yield forces due to cracks and failed regions. (3) Superconducting magnet response due to seismic excitation. These analyses have been carried out using a variety of large capacity finite element computer codes that allow for the evaluation of stresses in elastic or elastic-plastic zones and around singularities in the magnet structure. Thus far, these analyses have been carried out on UWMAK-I type magnet systems. (auth)
Date: January 1, 1975
Creator: Lehner, J.; Reich, M.; Powell, J.; Bezler, P.; Gardner, D.; Yu, W. et al.
System: The UNT Digital Library
The ICRF antennas for TFTR (open access)

The ICRF antennas for TFTR

Two compact loop antennas have been designed to provide ion cyclotron resonant frequency (ICRF) heating for TFTR. The antennas can convey a total of 10 MW to accomplish core heating in either high-density or high-temperature plasmas. The near-term goal of heating TFTR plasmas and the longer-term goals of ease in handling (for remote maintenance) and high reliability (in an inaccessible tritium tokamak environment) were major considerations in the antenna designs. The compact loop configuration facilitates handling because the antennas fit completely through their ports. Conservative design and extensive testing were used to attain the reliability required for TFTR. This paper summarizes how these antennas will accomplish these goals. 5 figs, 1 tab.
Date: January 1, 1988
Creator: Hoffman, D. J.; Colestock, P. L.; Gardner, W. L.; Hosea, J. C.; Nagy, A.; Stevens, J. et al.
System: The UNT Digital Library
Measurement of the W boson helicity in top quark decay at D0 (open access)

Measurement of the W boson helicity in top quark decay at D0

The authors present a measurement of the fraction f{sub +} of right-handed W bosons produced in top quark decays, based on a candidate sample of t{bar t} events in the {ell}+jets and dilepton decay channels corresponding to an integrated luminosity of 370 pb{sup -1} collected by the D0 detector at the Fermilab Tevatron p{bar p} Collider at {radical}s = 1.96 TeV. They reconstruct the decay angle {theta}* for each lepton. By comparing the cos{theta}* distribution from the data with those for the expected background and signal for various values of f{sub +}, they find f{sub +} = 0.056 {+-} 0.080(stat) {+-} 0.057(syst). (f{sub +} < 0.23 at 95% C.L.), consistent with the standard model prediction of f{sub +} = 3.6 x 10{sup -4}.
Date: September 1, 2006
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
System: The UNT Digital Library
SUDOKU A STORY & A SOLVER (open access)

SUDOKU A STORY & A SOLVER

Sudoku, also known as Number Place, is a logic-based placement puzzle. The aim of the puzzle is to enter a numerical digit from 1 through 9 in each cell of a 9 x 9 grid made up of 3 x 3 subgrids (called ''regions''), starting with various digits given in some cells (the ''givens''). Each row, column, and region must contain only one instance of each numeral. Completing the puzzle requires patience and logical ability. Although first published in a U.S. puzzle magazine in 1979, Sudoku initially caught on in Japan in 1986 and attained international popularity in 2005. Last fall, after noticing Sudoku puzzles in some newspapers and magazines, I attempted a few just to see how hard they were. Of course, the difficulties varied considerably. ''Obviously'' one could use Trial and Error but all the advice was to ''Use Logic''. Thinking to flex, and strengthen, those powers, I began to tackle the puzzles systematically. That is, when I discovered a new tactical rule, I would write it down, eventually generating a list of ten or so, with some having overlap. They served pretty well except for the more difficult puzzles, but even then I managed to develop an …
Date: April 1, 2006
Creator: GARDNER, P.R.
System: The UNT Digital Library