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Statistician's view of data analysis
A brief overview of statistical data analysis is provided with a view towards examining its role in the analysis of astronomy data. 5 figs.
Date:
July 1, 1986
Creator:
Friedman, J.H.
System:
The UNT Digital Library
Clay-mineral fabrics and chemistry in Salton Trough geothermal fields
Fluid production from, and hence the economic viability of, a geothermal field is related to the amount of clay minerals in the caprock and in the reservoir rocks. In both the East Mesa and Cerro Prieto fields in the Salton Trough of southern California, United States, and Baja California, Mexico, scanning electron micrography (SEM) has vividly documented the role of clay fabrics in deltaic quartz-sandstone reservoirs. For example, in East Mesa well 78-30 at 1630 m depth in a zone of quartz dissolution, the clay present in pores exhibits an irregular, crenulate, honeycomb fabric and has the following composition from energy dispersive x-ray analysis (EDAX): Si 61%, Al 25%, Fe 20%, Na 6%, K 2%, and Mg 1%. Platy clusters of clay (kaolinite) in Cerro Prieto well T-366 at 2522 m in a 300/sup 0/C geothermal aquifer were analyzed as: Si 62%, Al 25%, Mg 6%, and Fe 1%. In other samples, illite takes the form of wispy fibers whose intertwined ends form bridges across pores. These clay fabrics appear to reduce permeability significantly by clogging the pore throats, even though dissolution porosity ranges from 25 to 35%. Nineteen wells have been studied to date.
Date:
July 1, 1981
Creator:
Haar, S.V.; Wolgemuth, K. & Schatz, J.
System:
The UNT Digital Library
Experimental review of exclusive processes in two photon reactions
Recent experimental results on exclusive final stated produced in photon-photon interactions are reviewed. Comparisons between experiments and with perturbative QCD calculations are made for meson and baryon pair production. New results on vector meson pair (rho/sup 0/rho/sup 0/,rho/sup 0/omega,rho/sup 0/phi,...) production and production of multiparticle (KK..pi pi..,K*K..pi..,...) final states are summarized. 34 refs.
Date:
July 1, 1986
Creator:
Ronan, M. T.
System:
The UNT Digital Library
Condensed Matter at High Shock Pressures
Experimental techniques are described for shock waves in liquids: Hugoniot equation-of-state, shock temperature and emission spectroscopy, electrical conductivity, and Raman spectroscopy. Experimental data are reviewed and presented in terms of phenomena that occur at high densities and temperatures in shocked He, Ar, N/sub 2/, CO, SiO/sub 2/-aerogel, H/sub 2/O, and C/sub 6/H/sub 6/. The superconducting properties of Nb metal shocked to 100 GPa (1 Mbar) and recovered intact are discussed in terms of prospects for synthesizing novel, metastable materials. Ultrahigh pressure data for Cu is reviewed in the range 0.3 to 6TPa (3 to 60 Mbar). 56 refs., 9 figs., 1 tab.
Date:
July 12, 1985
Creator:
Nellis, W. J.; Holmes, N. C.; Mitchell, A. C.; Radousky, H. B. & Hamilton, D.
System:
The UNT Digital Library
New experiments on few-electron very heavy atoms
New experiments, to test quantum electrodynamics (QED) in strong Coulomb fields and to study atomic collisions at ultrarelativistic energies, are proposed. A 0.1% measurement of the 2/sup 2/P/sub 1/2/-2/sup 2/S/sub 1/2/ splitting in lithium like uranium (Z=92) and the 2/sup 3/P/sub 0/ - 2/sup 3/S/sub 1/ splitting in heliumlike uranium is proposed as a sub 1% test of the Lamb shift in a strong Coulomb field. Measurements of the hyperfine splitting of hydrogenlike thallium (Z=81) and the g/sub j/ factor of the ground state of hydrogenlike uranium are propsed as a test of the QED contribution to the magnetic moment of an electron bound in a strong Coulomb field. Measurements of capture cross sections for ultra relativistic very heavy nuclei are proposed to look for the capture of electrons from pair production. 40 refs., 7 figs., 2 tabs.
Date:
July 1, 1985
Creator:
Gould, H.
System:
The UNT Digital Library
Fixed point structure of quenched, planar quantum electrodynamics
Gauge theories exhibiting a hierarchy of fermion mass scales may contain a pseudo-Nambu-Boldstone boson of spontaneously broken scale invariance. The relation between scale and chiral symmetry breaking is studied analytically in quenched, planar quantum electrodynamics in four dimensions. The model possesses a novel nonperturbative ultraviolet fixed point governing its strong coupling phase which requires the mixing of four fermion operators. 12 refs.
Date:
July 1, 1986
Creator:
Love, S.T.
System:
The UNT Digital Library
Pre-tinning and flux considerations on the reliability of solder surface
The kinetics of wetting were studied on several different prepared surfaces of copper (Cu) to simulate the microstructure observed in pre-tinned Cu-clad printed circuit boards. The results illustrate the effectiveness of pre-tinning in maintaining the solderability of Cu surfaces. Pre-tinning with Pb-rich solder (95Pb-5Sn) is particularly effective since solderability is preserved even after a relatively long aging treatment. On the other hand, pre-tinning with eutectic solder risks the loss of solderability during aging or baking due to surface exposure of an {var epsilon}-phase intermetallic with poor wetting properties. The results also confirm the presence of carbon in pre-tinned specimens due to the use of flux. The effect of carbon on solderability is not yet known. 13 refs., 8 figs., 1 tab.
Date:
July 1, 1991
Creator:
Sunwoo, A.J. (Lawrence Livermore National Lab., CA (United States)); Morris, J.W. Jr. (Lawrence Berkeley Lab., CA (United States)) & Lucey, G.K. (Harry Diamond Labs., Adelphi, MD (United States))
System:
The UNT Digital Library
Fluorescence-pumped photolytic gas laser system for a commercial laser fusion power plant
The first results are given for the conceptual design of a short-wavelength gas laser system suitable for use as a driver (high average power ignition source) for a commercial laser fusion power plant. A comparison of projected overall system efficiencies of photolytically excited oxygen, sulfur, selenium and iodine lasers is described, using a unique windowless laser cavity geometry which will allow scaling of single amplifier modules to 125 kJ per aperture for 1 ns pulses. On the basis of highest projected overall efficiency, a selenium laser is chosen for a conceptual power plant fusion laser system. This laser operates on the 489 nm transauroral transition of selenium, excited by photolytic dissociation of COSe by ultraviolet fluorescence radiation. Power balances and relative costs for optics, electrical power conditioning and flow conditioning of both the laser and fluorescer gas streams are discussed for a system with the following characteristics: 8 operating modules, 2 standby modules, 125 kJ per module, 1.4 pulses per second, 1.4 MW total average power. The technical issues of scaling visible and near-infrared photolytic gas laser systems to this size are discussed.
Date:
July 14, 1977
Creator:
Monsler, M.J.
System:
The UNT Digital Library
Thermoelectric properties of bismuth-antimony thin films
Thermoelectrics have a wide range of potential applications in the temperature range of 0/sup 0/ to 100/sup 0/C. In an effort to enhance the feasibility of thermoelectrics, we have begun investigation of potentially cheaper materials and cheaper techniques for thermoelectrics. Two features of bismuth and antimony have influenced our work. First, Horst and Williams have reported quite respectable figure of merit values in bulk single crystals of bismuth-antimony, up to 2.5 x 10/sup -3/ at room temperature. Second, bismuth and antimony are an order of magnitude cheaper in cost compared to selenium and tellurium, making this binary alloy a natural candidate to reduce the cost of thermoelectric devices. Our avenue of approach involves a simplification of the fabrication process using an established technique of solid-state electronics: thin-film deposition. We have recently begun to investigate the extent to which the favorable properties of bulk Bi-Sb are preserved in thin films. Some of the preliminary data coming out of this ongoing investigation are reported.
Date:
July 1, 1980
Creator:
Treffny, J. & Jayadev, T.S.
System:
The UNT Digital Library
Concerning the generation of very high pressures for EOS studies with ultra-high power laser pulses
The use of basic physical and geometric principles, coupled with current laser technology, seems likely to extend experimental hyperbaric physics investigations from the megabar region into the portions of parameter space in which the ideal (degenerate) Fermi gas approximation is valid for even the highest Z materials. Implosions and speed-multiplying rectilinear stacks of flat plates seem particularly apt techniques for the near-term, transient attainment of pressure of 10/sup 9/ atmospheres in the laboratory, and laser-energized pulsed x-ray ''cameras'' appear suitable for analyzing the basic properties of matter under such conditions.
Date:
July 1, 1977
Creator:
Wood, L. L.; Keeler, R. N. & Nuckolls, J. H.
System:
The UNT Digital Library
TMX tandem-mirror experiments and thermal-barrier theoretical studies
This paper describes recent analysis of energy confinement in the Tandem Mirror Experiment (TMX). TMX data also indicates that warm plasma limits the amplitude of the anisotropy driven Alfven ion cyclotron (AIC) mode. Theoretical calculations show strong AIC stabilization with off-normal beam injection as planned in TMX-U and MFTF-B. This paper reports results of theoretical analysis of hot electrons in thermal barriers including electron heating calculations by Monte Carlo and Fokker-Planck codes and analysis of hot electron MHD and microinstability. Initial results from the TMX-U experiment are presented which show the presence of sloshing ions.
Date:
July 29, 1982
Creator:
Simonen, T. C.; Baldwin, D. E. & Allen, S. L.
System:
The UNT Digital Library
Triple-jet structures in proton-proton interactions
In this experiment, which uses a superconducting solenoid at the CERN ISR, a large sample of two-jet events produced in proton-proton collisions at 62 GeV centre-of-mass energy has been examined for evidence of three-jet structures; that is, for the presence of events in which three particle jets can be separately identified at large transverse momenta relative to the initial proton directions, there also being spectator jets following these directions, making five jets in all. Such three-jet events are expected to be produced by gluon bremsstrahlung, as has been observed in the e/sup +/e/sup -/ case, but several additional mechanisms are expected in the case of hadronic collisions. The three-jet events are identified by cluster analysis, the particles of each event being sorted into the best three-cluster and two-cluster combinations. Results are briefly described. (WHK)
Date:
July 1, 1981
Creator:
Angelis, A. L. S.; Besch, H. J. & Blumenfeld, B. J.
System:
The UNT Digital Library
Unification of quantum theory and classical physics
A program is described for unifying quantum theory and classical physics on the basis of the Copenhagen-interpretation idea of external reality and a recently discovered classical part of the electromagnetic field. The program effects an integration of the intuitions of Heisenberg, Bohr, and Einstein.
Date:
July 1, 1985
Creator:
Stapp, Henry P.
System:
The UNT Digital Library
Mini-jet and particle production in ultra-relativistic heavy ion collisions
Mini-jet and particle production are studied in the framework of HIJING Monte Carlo model which can describe pp and p{bar p} collisions well from ISR to Fermilab Tevatron energies. Mini-jets are shown to have eminent contributions to particle production in ultra-relativistic heavy ion collisions. However, parton shadowing and jet quenching also have important effects and can be studied by single particle distributions. 19 refs., 5 figs.
Date:
July 1, 1991
Creator:
Wang, Xin-Nian.
System:
The UNT Digital Library
Materials surface modification by plasma bombardment under simultaneous erosion and redeposition conditions
The first in-depth investigation of surface modification of materials by continuous, high-flux argon plasma bombardment under simultaneous erosion and redeposition conditions have been carried out for copper and 304 stainless steel using the PISCES facility. The plasma bombardment conditions are: incident ion flux range from 10/sup 17/ to 10/sup 19/ ions sec/sup -1/cm/sup -2/, total ion fluence is controlled between 10/sup 19/ and 10/sup 22/ ions cm/sup -2/, electron temperature range from 5 to 15 eV, and plasma density range from 10/sup 11/ to 10/sup 13/cm/sup -3/. The incident ion energy is 100 eV. The sample temperature is between 300 and 700K. Under redeposition dominated conditions, the material erosion rate due to the plasma bombardment is significantly smaller (by a factor up to 10) than that can be expected from the classical ion beam sputtering yield data. It is found that surface morphologies of redeposited materials strongly depend on the plasma bombardment condition. The effect of impurities on surface morphology is elucidated in detail. First-order modelings are implemented to interpret the reduced erosion rate and the surface evolution. Also, fusion related surface properties of redeposited materials such as hydrogen reemission and plasma driven permeation have been characterized.
Date:
July 1, 1986
Creator:
Hirooka, Y.; Goebel, D. M.; Conn, R. W.; Campbell, G. A.; Leung, W. K.; Wilson, K. L. et al.
System:
The UNT Digital Library
Critique of rationale for transmutation of nuclear waste
It has been suggested that nuclear transmutation could be used in the elimination or reduction of hazards from radioactive wastes. The rationale for this suggestion is the subject of this paper. The objectives of partitioning-transmutation are described. The benefits are evaluated. The author concludes that transmutation would appear at best to offer the opportunity of reducing an already low risk. This would not seem to be justifiable considering the cost. If non-radiological risks are considered, there is a negative total benefit. (DC)
Date:
July 1, 1980
Creator:
Smith, C.F. & Cohen, J.J.
System:
The UNT Digital Library
Adsorption of energy in photocatalytic reactors
The dissociation of water to hydrogen and oxygen requires energy ..delta..G/sub 298/ = 228 kJ/mole. By irradiating a semiconductor with light of energy greater than this amount, one may produce electrons in the excited state and electron vacancies at the surface that can perform the photochemical reduction (2H/sup +/ + 2e/sup -/ ..-->.. 2H ..-->.. H/sub 2/) and oxidation (20H/sup -/ + 2/sup +/ ..-->.. H/sub 2/O/sub 2/ ..-->.. H/sub 2/O + (1/2)O/sub 2/). There are several semiconductors, SrTiO/sub 3/, TiO/sub 2/, CdS, and Fe/sub 2/O/sub 3/ among them, that can photodissociate water. Some possess sites for both reduction and oxidation, while others carry out the two processes at different surfaces. A reversible solid state reaction that involves changes in the transition metal and ion oxidation state must accompany the splitting of water. Platinum, rhodium, and ruthenium oxide, when deposited on the semiconductor, serve as catalysts that accelerate the water photodissociation. These additives accelerate the recombination of hydrogen and oxygen atoms, shift the semiconductor Fermi level to a more favorable position that improves the thermodynamic feasibility for the process, accelerate electron transport, and inhibit side reactions like the photoreduction of oxygen. Many of the elementary reaction steps leading to photoproduction …
Date:
July 1, 1985
Creator:
Somorjai, G.A.
System:
The UNT Digital Library
A PC-based telemetry system for acquiring and reducing data from multiple PCM streams
The Solar Energy Research Institute's (SERI) Wind Research Program is using Pulse Code Modulation (PCM) telemetry data-acquisition systems to study horizontal-axis wind turbines. Many PCM systems are combined for use in test installations that require accurate measurements from a variety of different locations. SERI has found them ideal for data-acquisition from multiple wind turbines and meteorological towers in wind parks. A major problem has been in providing the capability to quickly combine and examine incoming data from multiple PCM sources in the field. To solve this problem, SERI has developed a low-cost PC-based PCM telemetry data-reduction system to facilitate quick, in-the-field multiple-channel data analysis. Called the PC-PCM System,'' it consists of two basic components. First, PC-compatible hardware boards are used to decode and combine multiple PCM data streams. Up to four hardware boards can be installed in a single PC, which provides the capability to combine data from four PCM streams directly to PC disk or memory. Each stream can have up to 62 data channels. Second, a software package written for use under DOS was developed to simplify data-acquisition control and management. The software provides a quick, easy-to-use interface between the PC and multiple PCM data streams. Called the …
Date:
July 1, 1991
Creator:
Simms, D A & Butterfield, C P
System:
The UNT Digital Library
Reaction rate calculations via transmission coefficients
The transmission coefficient of a wavepacket traversing a potential barrier can be determined by steady state calculations carried out in imaginary time instead of by real time dynamical calculations. The general argument is verified for the Eckart barrier potential by a comparison of transmission coefficients calculated from real and imaginary time solutions of the Schroedinger equation. The correspondence demonstrated here allows a formulation for the reaction rate that avoids difficulties due to both rare events and explicitly time dependent calculations. 5 refs., 2 figs.
Date:
July 11, 1985
Creator:
Feit, M. D. & Alder, B. J.
System:
The UNT Digital Library
The use of a relaxation method to calculate the 3D magnetic field contribution of an iron yoke
A computational procedure has been developed for calculating the three-dimensional field produced by an axisymmetric iron yoke of high permeability in the presence of a system of conductors. The procedure is particularly applicable to the end regions of multipole magnets of the sort used in particle accelerators. The field produced by the conductors is calculated using the Biot-Savart law. We speak of the field contribution of the yoke as an image field'' although it is associated with a distinctly diffuse distribution of image currents or magnetic moments. At every point on the boundary of the yoke the total scalar potential is constant, so V{sup i} = -V{sup d} where i=image and d=direct contribution from the conductors. If we describe both potentials as a series of harmonic components'' with respect to azimuthal dependence, then the nature of the boundary condition is such that a de-coupling of one harmonic component from another is preserved and therefore it is also true that V{sup i}(n)=-V{sup d}(n) at the iron interface, where n is a harmonic number. If we solve the appropriate individual differential equations for the scalar potential functions V{sup i}(n) throughout the iron-free region, with the proper applied boundary condition for the scalar …
Date:
July 1, 1991
Creator:
Caspi, S.; Helm, M. & Laslett, L.J.
System:
The UNT Digital Library
Low frequency noise in freely suspended tin films at the superconducting transition. [Spectral density]
The spectral density, S/sub v/(f), of the voltage noise across 1-D current-biased tin films has been measured at the superconducting transition. Each film was freely suspended between two thermal clamps a distance L apart in a vacuum can. A thin layer of lead was evaporated on the outer portion of the films to leave an uncoated middle region of length l. S/sub v/(f) was flat at frequencies below f/sub L/ approximately D/L/sup 2/, where D is the thermal diffusivity. At frequencies between f/sub L/ and f/sub l/ approximately (L/l)/sup 2/f/sub L/ the slope was typically -0.8, while at frequencies above f/sub l/ the slope was somewhat less steep than -1.5. The shape and magnitude of S/sub v/(f) were in good agreement with an equilibrium temperature fluctuation model in which the temperature fluctuations are spatially uncorrelated. Measurements of the autocorrelation function also strongly supported this model. These results are in contrast with those obtained for normal films and films at the superconducting transition supported by substrates, for which a model was required with spatially correlated fluctuations. It is concluded that the 1/f noise for films on substrates is mediated by an interaction between the substrate and the film.
Date:
July 1, 1977
Creator:
Ketchen, M.B. & Clarke, J.
System:
The UNT Digital Library
The puzzles of surface science and recent attempts to explain them
Surfaces have several unique properties that remain unexplained on the atomic level. These include (1) the unique chemical activity of rough surfaces, (2) the breaking of chemical bonds in narrow temperature ranges; and (3) the role of co-adsorption and strongly adsorbed monolayers during catalysis and tribological change (friction, lubrication). The dynamic surface restructuring model and surface structure induced variations in local density of states that have been suggested to rationalize the surface behavior await experimental confirmation. 24 refs., 10 figs., 2 tabs.
Date:
July 1, 1990
Creator:
Somorjai, G.A.
System:
The UNT Digital Library
J/psi results from Mark III
Results from the Mark III collaboration on related hadronic and radiative decays of the J/psi are presented. From a data sample of 5.8 million produced J/psi decays disintegrations into either ..gamma.., ..omega.., or phi plus K anti K, K anti K..pi.., eta..pi pi.. or ..pi pi.. are studied. These results are valuable in the understanding of the nature and composition of the 2/sup + +/theta(1720) and the 0/sup - +/iota(1440), the primary candidates for gluonic matter.
Date:
July 1, 1986
Creator:
Stockhausen, W.
System:
The UNT Digital Library
Phase Equilibria in High Energy Density PVDF-Based Polymers
Article on phase equilibria in high energy density PVDF-based polymers.
Date:
July 27, 2007
Creator:
Ranjan, Vivek; Yu, Liping; Buongiorno Nardelli, Marco & Bernholc, Jerry
System:
The UNT Digital Library