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Search for narrow states produced in the reaction. pi. /sup -/p. -->. n +. gamma. 's at 13 GeV/c (open access)

Search for narrow states produced in the reaction. pi. /sup -/p. -->. n +. gamma. 's at 13 GeV/c

A double arm lead-glass lead-scintillator calorimeter system was used to search for narrow states, such as the eta/sub c/, produced in the exclusive reactions ..pi../sup -/p ..-->.. ..gamma gamma..n, ..pi../sup -/p ..-->.. ..pi../sup 0/..gamma..n, and ..pi../sup -/p ..-->.. ..pi../sup 0/..pi../sup 0/n at 13 GeV/c. A 90% c.l. upper limit sigma.BR < 260 pb was found for ..gamma gamma.. states with masses from 2.6 to 3.1 GeV/c/sup 2/. Corresponding limits on narrow ..pi../sup 0/..gamma.. and ..pi../sup 0/..pi../sup 0/ states are also given.
Date: July 7, 1980
Creator: Chiang, I. H.; Johnson, R. A. & Kwan, B.
System: The UNT Digital Library
Bubble-chamber experiments on charmed-particle lifetimes (open access)

Bubble-chamber experiments on charmed-particle lifetimes

The three current bubble-chamber experiments on charmed-particle lifetimes are compared. Their most recently released results are discussed.
Date: July 1, 1982
Creator: Field, R.C.
System: The UNT Digital Library
In-situ impurity measurements in PDX Edge plasma (open access)

In-situ impurity measurements in PDX Edge plasma

The surface analysis station of PDX combines several surface analysis techniques (AES, XPS, SIMS) for in-situ measurement of impurity fluxes in the edge-plasma. The major impurities deposited on a sample surface during nondiverted PDX discharges are oxygen, titanium (limiter material) and chlorine. The impurity fluxes measured at different radial positions decreased by a factor of ten from the plasma edge to the wall. The sample surface collecting the impurity ions is located behind a circular aperture. The observed broadening of the deposition profile of Ti relative to the aperture diameter enables an estimate to be made of the ratio of charge state/energy of Ti ions in the edge plasma. Time-resolved analyses of the deposited impurities are presented which indicate that the time behavior for various impurities may be quite different for different impurity species. This aspect is discussed in relation to probable impurity release mechanisms.
Date: July 1, 1980
Creator: Staib, P.; Dylla, H.F. & Rossnagel, S.M.
System: The UNT Digital Library
Scale effects in sliding friction: An experimental study (open access)

Scale effects in sliding friction: An experimental study

Solid friction is considered by some to be a fundamental property of two contacting materials, while others consider it to be a property of the larger tribosystem in which the materials are contained. A set of sliding friction experiments were designed to investigate the hypothesis that the unlubricated sliding friction between two materials is indeed a tribosystems-related property and that the relative influence of the materials properties or those of the machine on friction varies from one situation to another. Three tribometers were used: a friction microprobe (FMP), a typical laboratory-scale reciprocating pin-on-flat device, and a heavy-duty commercial wear tester. The slider material was stainless steel (AISI 440C) and the flat specimen material was an ordered alloy of Ni{sub 3}Al (IC-50). Sphere-on-flat geometry was used at ambient conditions and at normal forces ranging from 0.01 N to 100 N and average sliding velocities of 0.01 to 100.0 mm/s. The nominal, steady-state sliding friction coefficient tended to decrease with increases in normal force for each of the three tribometers, and the steady state value of sliding friction tended to increase as the mass of the machine increased. The variation of the friction force during sliding was also a characteristic of the …
Date: July 24, 1991
Creator: Blau, P.J.
System: The UNT Digital Library
Modulated molecular beam mass spectrometric studies of the high temperature pyrolysis of hydrocarbons (open access)

Modulated molecular beam mass spectrometric studies of the high temperature pyrolysis of hydrocarbons

The pyrolysis products of benzene and toluene were studied as functions of temperature (up to 2000/sup 0/C) and pressure. Above 1400/sup 0/C, most of the larger species are unstable; above 1700/sup 0/C, no species heavier than C/sub 6/H/sub 6/ are observed at any pressure. Above 1500/sup 0/C and at higher pressures, the products are dominated by species containing even numbers of carbon atoms (C/sub 2/ to C/sub 12/). While polyacetylenes up to C/sub 8/H/sub 2/ were observed, they are present in low abundances, with the max concentrations occurring at 1350/sup 0/C. Polycyclic aromatic hydrocarbons are formed readily. 6 figures. (DLC)
Date: July 1, 1979
Creator: Smith, R. D.
System: The UNT Digital Library
Proceedings of the 1977 Isabelle Summer Workshop. [Seventy-four papers] (open access)

Proceedings of the 1977 Isabelle Summer Workshop. [Seventy-four papers]

A report is given of the activities of the 1977 ISABELLE Summer Workshop, held from July 18 to 29, 1977 at the Brookhaven National Laboratory. An abstract was prepared for each of the seventy-four separate presentations for inclusion in DOE Energy Research Abstracts (ERA). (PMA)
Date: July 18, 1977
Creator: unknown
System: The UNT Digital Library
Numerical analysis of laminar forced convection in a spherical annulus (open access)

Numerical analysis of laminar forced convection in a spherical annulus

Calculations of steady laminar incompressible fluid-flow and heat transfer in a spherical annulus are presented. Steady pressures, temperatures, velocities, and heat transfer coefficients are calculated for an insulated outer sphere and a 0/sup 0/C isothermal inner sphere with 50/sup 0/C heated water flowing in the annulus. The inner sphere radius is 13.97 cm, the outer sphere radius is 16.83 cm and the radius ratio is 1.2. The transient axisymmetric equations of heat, mass, and momentum conservation are solved numerically in spherical coordinates. The transient solution is carried out in time until steady state is achieved. A variable mesh is used to improve resolution near the inner sphere where temperature and velocity gradients are steep. It is believed that this is the first fully two-dimensional analysis of forced flow in a spherical annulus. Local and bulk Nusselt numbers are presented for Reynolds numbers from 4.4 to 440. Computed bulk Nusselt numbers ranged from 2 to 50 and are compared to experimental results from the literature. Inlet flow jetting off the inner sphere and flow separation are predicted by the analysis. The location of wall jet separation was found to be a function of Reynolds number, indicating the location of separation depends …
Date: July 21, 1980
Creator: Tuft, D.B.
System: The UNT Digital Library
Highlights of the heavy ion fusion symposium (open access)

Highlights of the heavy ion fusion symposium

The current status and prospects for inertial confinement fusion based on the use of intense beams of heavy ions will be described in the light of results presented at the International Symposium on Heavy Ion Fusion, (Washington, DC, May 27-29, 1986).
Date: July 1, 1986
Creator: Keefe, D.
System: The UNT Digital Library
Operational, control and protective system transient analyses of the closed-cycle GT-HTGR power plant (open access)

Operational, control and protective system transient analyses of the closed-cycle GT-HTGR power plant

This paper presents a description of the analyses of the control/protective system preliminary designs for the gas turbine high-temperature gas-cooled reactor (GT-HTGR) power plant. The control system is designed to regulate reactor power, control electric load and turbine speed, control the temperature of the helium delivered to the turbines, and control thermal transients experienced by the system components. In addition, it provides the required control programming for startup, shutdown, load ramp, and other expected operations. The control system also handles conditions imposed on the system during upset and emergency conditions such as loop trip, reactor trip, or electrical load rejection.
Date: July 1, 1980
Creator: Openshaw, F.L. & Chan, T.W.
System: The UNT Digital Library
Hyperfine Structure of the Electronic Ground States of Rb$sup 85$ And Rb$sup 8$$sup 7$ (open access)

Hyperfine Structure of the Electronic Ground States of Rb$sup 85$ And Rb$sup 8$$sup 7$

None
Date: July 15, 1962
Creator: Penselin, S.; Moran, T.; Cohen, V.W. & Winkler, G.
System: The UNT Digital Library
Liquid-metal embrittlement of refractory metals by molten plutonium (open access)

Liquid-metal embrittlement of refractory metals by molten plutonium

Embrittlement by molten plutonium of the refractory metals and alloys W-25 wt % Re, tantalum, molybdenum, and Ta-10 wt % W was studied. At 900/sup 0/C and a strain rate of 10/sup -4/ s/sup -1/, the materials tested may be ranked in order of decreasing susceptibility to liquid-plutonium embrittlement as follows: molybdenum, W-25 wt % Re, Ta-10 wt % W, and tantalum. These materials exhibited a wide range in susceptibility. Embrittlement was found to exhibit a high degree of temperature and strain-rate dependence, and we present arguments that strongly support a stress-assisted, intergranular, liquid-metal corrosion mechanism. We also believe microstructure plays a key role in the extent of embrittlement. In the case of W-25 wt % Re, we have determined that a dealloying corrosion takes place in which rhenium is selectively withdrawn from the alloy.
Date: July 1, 1980
Creator: Lesuer, D. R.; Bergin, J. B.; McInturff, S. A. & Kuhn, B. A.
System: The UNT Digital Library
Double-mode pulsation (open access)

Double-mode pulsation

Double mode pulsation is a very pervasive phenomenon in stars all over the Hertzsprung-Russell diagram. In order of increasing radius, examples are: ZZ Ceti stars, the sun, the delta Scuti stars, RR Lyrae variables, the ..beta.. Cephei variables and those related to them, Cepheids, and maybe even the Mira stars. These many modes have been interpreted as both radial and nonradial modes, but in many cases the actual mode has not been clearly identified. Yellow giants seem to be the most simple pulsators with a large majority of the RR Lyrae variables and Cepheids showing only one pulsation period. We limit this review to those very few cases for classical Cepheids and RR Lyrae variables which display two modes. For these we know many facts about these stars, but the actual cause of the pulsation in two modes simultaneously remains unknown.
Date: July 30, 1982
Creator: Cox, A. N.
System: The UNT Digital Library
Problem of long-range forces in the computer simulation of condensed media (open access)

Problem of long-range forces in the computer simulation of condensed media

Simulation (both Monte Carlo and molecular dynamical) has become a powerful tool in the study of classical systems of particles interacting with short-range pair potentials. For systems involving long-range forces (e.g., Coulombic, dipolar, hydrodynamic) it is a different story. Relating infinite-system properties to the results of computer simulation involving relatively small numbers of particles, periodically replicated, raises difficult and challenging problems. The purpose of the workshop was to bring together a group of scientists, all of whom share a strong direct interest in clearly formulating and resolving these problems. There were 46 participants, most of whom have been actively engaged in simulations of Hamiltonian models of condensed media. A few participants were scientists who are not primarily concerned, themselves, with simulation, but who are deeply involved in the theory of such models.
Date: July 1, 1980
Creator: Ceperely, D. (ed.)
System: The UNT Digital Library
The giant ion sources of neutral-beam injectors for fusion (open access)

The giant ion sources of neutral-beam injectors for fusion

All large tokamak fusion experiments today use auxiliary heating by multi-megawatt beams of neutral isotopes of hydrogen injected with energies in the neighborhood of 100 keV per atom. This requires reliable operation of large ion sources, each delivering many tens of amperes of protons or deuterons, and soon even tritons. For meaningful experiments these sources must operate with pulse durations measured in seconds, although the duty factor may still be small. It is remarkable that the successful sources developed in Europe, Japan and the US are all very similar in basic design: the plasma is produced by diffuse low-pressure high-current discharges in magnetic multipole buckets'' was distributed thermionically emitting cathodes. This paper briefly reviews the principal considerations and the basic physics of these sources, and summarizes the collective experience to date and describes the impressive recent performance of the US Common Long Pulse Source, as a specific example. 20 refs., 6 figs., 2 tabs.
Date: July 1, 1989
Creator: Kunkel, W.B.
System: The UNT Digital Library
Collision of fast highly charged ions in gas targets: ionization, recoil-ion production, and charge transfer (open access)

Collision of fast highly charged ions in gas targets: ionization, recoil-ion production, and charge transfer

Electron-capture, ionization, and recoil-ion-production cross sections are measured and calculated for fast highly charged projectiles in hydrogen and rare-gas targets. Recoil-ion-production cross sections are found to be large; the low energy and high charge states of the recoil ions make them useful for subsequent collision studies.
Date: July 1, 1982
Creator: Schalchter, A.S.; Berkner, K.H. & Beyer, H.F.
System: The UNT Digital Library
Vectorially photoinduced electron-transfer processes across water-in-oil interfaces of microemulsions (open access)

Vectorially photoinduced electron-transfer processes across water-in-oil interfaces of microemulsions

Artificial photosynthetic devices are potential fuel sources. The basic idea in the design of such devices is a photosensitized electron-transfer that yields chemical species capable of reducing and oxidizing water to hydrogen and oxygen. A fundamental difficulty in effecting this transfer is the thermodynamically favored back reactions of the intermediary redox species. An interfacial model composed of a water-in-oil microemulsion is suggested to provide the separation of these redox species, thereby preventing back-reactions. This model is designed to accomplish the photodecomposition of water in two separate water-in-oil microemulsions coupled by a redox reaction. Phase-transfer of one of the redox products from the water-in-oil interface to the continuous organic phase is the principle by which separation is achieved. The oxidation and reduction sites of the general model have been constructed. One system includes the photosensitized oxidation of a donor, EDTA, solubilized in the water pool, benzylnicotinamide acts as a primary acceptor that mediates by the phase transfer principle the reduction of a secondary acceptor, dimethylamino-azobenzene, solubilized in the continuous organic phase. In system two, involving the photosensitized reduction of methyl viologen, by tris(2,2'bipyridine)Ru(2+), thioophenol is used as the donor and its oxidation product is phase transferred to the continuous organic phase. …
Date: July 1, 1980
Creator: Willner, I.; Otvos, J. W. & Calvin, M.
System: The UNT Digital Library
Soft and hard pomerons: Is there a distinction (open access)

Soft and hard pomerons: Is there a distinction

One of the big unsolved problems of QCD remains the problem of the Pomeron: what is the relation of high energy elastic and diffractive phenomena to the underlying theory This is not a subject in which I have actively worked. But my interest in it has in this year increased greatly. The reason has to do with ideas for experimentation at SSC/LHC which either directly address the problem or which require the understanding of strong-interaction diffractive phenomena as backgrounds for discovery-physics processes involving electroweak boson exchanges. I will in this talk omit these motivations, which can be found elsewhere, and instead concentrate on some personal veiwpoints regarding the Pomeron which may or may not be conventional. The main question has to do with the distinction between the original, old-fashioned soft'' Pomeron of the 1960s, built out of multiperipheral hadron-exchanges, and the more modern perturbative-QCD hard'' Pomeron, built out of multiperipheral gluon exchanges. The perspective I offer comes mainly from two sources: one is heavy-flavor physics, and the other is the Manohar-Georgi view of constituent quark physics. 27 refs., 5 figs.
Date: July 1, 1991
Creator: Bjorken, J. D.
System: The UNT Digital Library
Facility for the testing of the TFTR prototype neutral beam injector (open access)

Facility for the testing of the TFTR prototype neutral beam injector

The design of the prototype neutral beam injection system for TFTR is nearing completion at the Lawrence Livermore Laboratory. This paper describes some of the features of the facility at the Lawrence Berkeley Laboratory where this prototype will be assembled and tested.
Date: July 1, 1977
Creator: Haughian, J.M.
System: The UNT Digital Library
Radiative J/psi decays and the pseudoscalar puzzle (open access)

Radiative J/psi decays and the pseudoscalar puzzle

Recent results on radiative decays of the J/PSI, obtained by the SPEAR detectors Mark III and Crystal Ball and the DCI detector DM2 at Orsay, are presented. The status of the glueball candidates theta(1690), iota(1460), and xi(220), and the decays J/PHI ..-->.. ..gamma.. Vector Vector are reviewed. A coupled channel analysis of iota(1460) decays to K anti K..pi.., rho rho, ..omega omega.., and ..gamma..rho is presented which may help to understand the pseudoscalar sector in radiative J/PHI decays. 42 refs., 16 figs.
Date: July 1, 1985
Creator: Wermes, N.
System: The UNT Digital Library
Report of the Intermediate-)ital p)/sub Perpendicular/ Detector Group: A Beauty Spectrometer for the SSC (Superconducting Super Collider) (open access)

Report of the Intermediate-)ital p)/sub Perpendicular/ Detector Group: A Beauty Spectrometer for the SSC (Superconducting Super Collider)

A ''Beauty Spectrometer'' has been designed for studies of B physics at the SSC. The ultimate goal is a definitive measurement of CP violation in the B system. The spectrometer consists of two stages and occupies one side of an intermediate-luminosity interaction region. An upstream, or intermediate, stage extends from the interaction point to 14 m and covers the angular region from 57 mrad (3.3 degree) to 350 mrad (20 degree). The forward stage extends to 77 m and to angles down to 5.7 mrad. The design includes silicon microstrip detectors, conventional tracking, momentum analysis, and hadron and lepton identification. While no fundamental problems have been found, the detector must deal with unprecedented particles fluxes, trigger rates, and data rates. 11 refs., 10 figs., 5 tabs.
Date: July 1, 1987
Creator: Foley, K. J.; Buchanan, C. D.; Morrison, R. J.; McHugh, S. W.; Witherell, M. S.; Atac, M. et al.
System: The UNT Digital Library
Measurement of pressure, fluidized bed level, and density in the Synthane Pilot Plant coal gasifier (open access)

Measurement of pressure, fluidized bed level, and density in the Synthane Pilot Plant coal gasifier

Fluid bed densities and levels are usually obtained from measurement of differential pressures between taps with a known vertical separation. Historically, this measurement has been difficult in high pressure coal gasification processes primarily due to plugging of the pressure taps and process instrument tubing. Likewise, the achievement of accurate and reliable pressure and differential pressure recordings is affected by similar circumstances. These typical problems were experienced at the SYNTHANE Pilot Plant at Bruceton which is operated for the U.S. Energy Research and Development Administration by the C.E. Lummus Company. Major changes were required in instrument location and selection, piping configuration, and methods of purging. Consistent and accurate data is now obtained. Recommendations for the installation and operation of such instruments are given.
Date: July 1, 1977
Creator: Bailey, D. M. & Runnels, O. D.
System: The UNT Digital Library
Fragmentation model applied to exclusive final states in photon-photon collisions (open access)

Fragmentation model applied to exclusive final states in photon-photon collisions

Monte Carlo calculations with the Lund string fragmentation model are compared to experimental results on the reactions ..gamma gamma -->..2..pi../sup +/2..pi../sup -/, ..gamma gamma -->..K/sup +/K/sup -/..pi../sup +/..pi../sup -/ and ..gamma gamma -->..p anti p..pi../sup +/..pi../sup -/. It is found, that when the parameters of the Lund model are tuned to low energy, inclusive multi hadron production in photon-photon collisions, the cross sections of exclusive processes near threshold are qualitatively reproduced. 14 refs., 3 figs.
Date: July 1, 1986
Creator: Buijs, A.
System: The UNT Digital Library
Plans for polarized beams at the SLC (open access)

Plans for polarized beams at the SLC

Precision tests of the electroweak interactions will soon be possible at the SLC and LEP. The SLC will be capable of providing longitudinal polarization of one incoming beam, the electrons, for such tests. Plans at the SLC to provide and monitor these beams are described, and some physics objectives are discussed. 5 refs., 10 figs.
Date: July 1, 1985
Creator: Prescott, Charles Y.
System: The UNT Digital Library
Kesterson crisis: Sorting out the facts (open access)

Kesterson crisis: Sorting out the facts

The Kesterson Reservoir was planned as a regulating facility to control drainage water discharges into the San Joaquin-Scaramento River Delta from the San Luis Drain'' which was to dispose of salt-ladin agricultural water. Anticipated environmental impacts of the Kesterson operations focused almost exclusively on problems related to seepage and water-logging of nearby lands. Reuse of drainage water for wetlands focused on excessive salinity. Drainage water entered the reservoir in 1978. By 1983 elevated levels of selenium were found with selenium poisoning causing deformed embryos of water birds, adult bird mortality and their poor reproductive success. An estimated 9000 kg of selenium was delivered to Kesterson between 1981 to 1986. This paper details the chronology of the Kesterson crisis and environmental remediation. 20 refs., 1 fig. (BJN)
Date: July 1, 1990
Creator: Benson, S.M. (Lawrence Berkeley Lab., CA (United States)); Delamore, M. & Hoffman, S. (Bureau of Reclamation, Sacramento, CA (United States). Mid-Pacific Region)
System: The UNT Digital Library