Relativistic shocks in electron-positron plasmas, and polar cap accretion onto neutron stars: Two non-linear problems in astrophysical plasma physics (open access)

Relativistic shocks in electron-positron plasmas, and polar cap accretion onto neutron stars: Two non-linear problems in astrophysical plasma physics

I outline particle simulations and theory of relativistic shock waves in an e/sup +-/ plasma. Magnetic reflection of particles is an essential role in the shock structure. Instability of the reflected particles in the shock front produces intense extraordinary mode radiation. Such shocks are candidates for the particle accelerator in plerions and in extragalactic jets only if the upstream Poynting flux composes no more than 10% of the total. I summarize analytical and numerical studies of radiation dominated accretion onto the magnetic poles of neutron stars. The upper limit to the photon luminosity depends upon magnetic confinement, not upon the dragging of photons into the star. Numerical solutions show the plasma forms large scale ''photon bubbles.'' I suggest the percolative loss of radiation controls the pressure and therefore the limits of magnetic confinement. Loss of magnetic confinement through resistive interchange instability is suggested as a means of generating TeV to PeV voltage drops along the magnetic field. 34 refs., 6 figs., 1 tab.
Date: August 15, 1988
Creator: Arons, J.
Object Type: Article
System: The UNT Digital Library
Results for the G-11 Outer Tube Test Piece (open access)

Results for the G-11 Outer Tube Test Piece

None
Date: July 15, 1988
Creator: Brown, D. P.; Gibbs, D. P.; Wu, K. C. & Horne, D. L.
Object Type: Report
System: The UNT Digital Library
Electron-atom collision studies using optically state selected beams. Progress report, May 15, 1987--May 14, 1988 (open access)

Electron-atom collision studies using optically state selected beams. Progress report, May 15, 1987--May 14, 1988

This report discusses progress made during the current contract period on the authors research program to study collisions between spin-polarized electrons and optically prepared atoms. The objective of this work is to stimulate a deeper theoretical understanding of the electron-atom interaction by providing more complete experimental measurements on colliding systems. By preparing the internal states of the collision partners before scattering, they are able to extract substantially more information about the scattering process than is available from more conventional measurements of differential cross sections. The authors are principally interested in observing the role played by spin in low energy electron-atom collisions. The additional information provided by these spin-dependent measurements can greatly enhance understanding of both exchange and the spin-orbit interaction in the scattering process. They have made substantial progress in the past three years in their measurements both of elastic and superelastic scattering of spin-polarized electrons from optically pumped sodium.
Date: November 15, 1988
Creator: Celotta, R. J. & Kelley, M. H.
Object Type: Report
System: The UNT Digital Library
ZPPR progress report: November 1987-January 1988 (open access)

ZPPR progress report: November 1987-January 1988

This report details activities for the time period of November, 1987 through January, 1988. Further results are presented from the axially heterogeneous assembly ZPPR-17, a part of the JUPITER-III program. The loading of the ZPPR-17C assembly, with 13 half-inserted control rods, is described along with operational measurements, calculation models, and measurements and prediction of criticality. From ZPPR-17A, calculated and measured results are given for reaction rates and measured results for bowing, expansion and small sample worth experiments. From the earlier metal-fuel ZPPR-15 program results are given for measurements and calculations of Doppler reactivity coefficients.
Date: February 15, 1988
Creator: Collins, P.J. & Brumbach, S.B.
Object Type: Report
System: The UNT Digital Library
Proposed RHIC 160 MHz RF System (open access)

Proposed RHIC 160 MHz RF System

None
Date: July 15, 1988
Creator: Griffin, J.
Object Type: Report
System: The UNT Digital Library
Determination of physical and mechanical properties of copper-clad molybdenum sheet (open access)

Determination of physical and mechanical properties of copper-clad molybdenum sheet

Selected physical and mechanical properties of copper-clad molybdenum sheet have been determined. Among those properties determined were: room-temperature density, coefficient of thermal expansion in the temperature range {minus}43 to 800 C, specific heat between {minus}40 and +150 C, thermal conductivity from {minus}50 to +150 C, electrical resistivity in the same temperature range, magnetic susceptibility and modulus of elasticity both at room temperature. Materials with several different copper/molybdenum thickness ratios and composite thicknesses were evaluated.
Date: August 15, 1988
Creator: Grobner, P. J.
Object Type: Report
System: The UNT Digital Library
Determination of physical and mechanical properties of copper-clad molybdenum sheet (open access)

Determination of physical and mechanical properties of copper-clad molybdenum sheet

Selected physical and mechanical properties of copper-clad molybdenum sheet have been determined. Among those properties determined were: room-temperature density, coefficient of thermal expansion in the temperature range {minus}43 to 800 C, specific heat between {minus}40 and +150 C, thermal conductivity from {minus}50 to +150 C, electrical resistivity in the same temperature range, magnetic susceptibility and modulus of elasticity both at room temperature. Materials with several different copper/molybdenum thickness ratios and composite thicknesses were evaluated.
Date: August 15, 1988
Creator: Grobner, P. J.
Object Type: Report
System: The UNT Digital Library
Polymer highlights for September 1975 (open access)

Polymer highlights for September 1975

Research programs in polymer chemistry are briefly described. The following polymers are under investigation for use as adhesives, nozzles, insulators, or fluid cushions: urethanes, teflon, TFE, Tefzel, Ryton, H Resin, Imidite 2803, PPQ, KELF 800, and KELF 5500. Areas of research application include geothermal and solar energy fields. (CBS)
Date: December 15, 1988
Creator: Hammon, H. G.; Althouse, L. P.; Buckner, A. T.; McKinley, B.; Walkup, C. M.; Rinde, J. et al.
Object Type: Report
System: The UNT Digital Library
RHIC Internal Beam Dump Preliminary Conceptual Design (open access)

RHIC Internal Beam Dump Preliminary Conceptual Design

None
Date: September 15, 1988
Creator: J., Stevens A.
Object Type: Report
System: The UNT Digital Library
Summary of the US Senior Committee on Environmental, Safety, and Economic Aspects of Magnetic Fusion Energy (ESECOM) (open access)

Summary of the US Senior Committee on Environmental, Safety, and Economic Aspects of Magnetic Fusion Energy (ESECOM)

ESECOM has completed a recent assessment of the competitive potential of magnetic fusion energy (MFE) compared to present and future fission energy sources giving particular emphasis to the interaction of environmental, safety, and economic characteristics. By consistently applying a set of economic and safety models to a set of MFE concepts using a wide range of possible material choices, power densities, power conversion methods, and fuel cycles, ESECOM finds that several different MFE concepts have the potential to achieve costs of electricity comparable to those of fission systems, coupled with significant safety and environmental advantages. 13 refs., 7 tabs.
Date: August 15, 1988
Creator: Logan, B. G.; Holdren, J. P.; Berwald, D. H.; Budnitz, R. J.; Crocker, J. G.; Delene, J. G. et al.
Object Type: Article
System: The UNT Digital Library
Some TPC (Time Projection Chamber) measurements in an oxygen beam at the AGS (open access)

Some TPC (Time Projection Chamber) measurements in an oxygen beam at the AGS

The principal detector for AGS Experiment 810 is a Time Projection Chamber (TPC) in which it is intended to measure momenta and angles of a major fraction of the charged particles from each light ion collision. This report describes the results of a test of a prototype of the TPC in a beam of (14.6 /times/ 16 = 233.6 GeV/c) oxygen ions run in June of this year.
Date: November 15, 1988
Creator: Love, W. A.; Bonner, B. E.; Buchanan, J. A.; Chan, C. S.; Chiou, C. N.; Clement, J. M. et al.
Object Type: Article
System: The UNT Digital Library
Using the circulating beam in the Fermilab antiproton accumulator for experiments (open access)

Using the circulating beam in the Fermilab antiproton accumulator for experiments

The Fermilab Accumulator is a storage ring optimized for stacking and stochastic cooling 8 GeV antiprotons for the Tevatron collider. Minor modifications have been made to provide for beam in the energy range 8.0-2.9 GeV of luminosity /approximately/10/sup 31/cm/sup -2/s/sup - 1/ with a hydrogen jet internal target. Experience to date consists of machine studies and detector engineering run with protons. 7 refs.
Date: August 15, 1988
Creator: MacLachlan, J.A.
Object Type: Article
System: The UNT Digital Library
Enzymatic desulfurization of coal. Second quarterly report, October 1--December 15, 1988 (open access)

Enzymatic desulfurization of coal. Second quarterly report, October 1--December 15, 1988

Our current efforts to develop clean coal technology emphasize the advantages of enzymatic desulfurization techniques and have specifically addressed the potential of using partially-purified extracellular microbial enzymes or commercially available enzymes. Our work is focused on the treatment of ``model`` organic sulfur compounds such as dibenzothiophene (DBT) and ethylphenylsulfide (EPS). Furthermore, we are designing experiments to facilitate the enzymatic process by means of a hydrated organic solvent matrix.
Date: December 15, 1988
Creator: Marquis, J. K. & Kitchell, J. P.
Object Type: Report
System: The UNT Digital Library
Enzymatic desulfurization of coal (open access)

Enzymatic desulfurization of coal

Our current efforts to develop clean coal technology emphasize the advantages of enzymatic desulfurization techniques and have specifically addressed the potential of using partially-purified extracellular microbial enzymes or commercially available enzymes. Our work is focused on the treatment of model'' organic sulfur compounds such as dibenzothiophene (DBT) and ethylphenylsulfide (EPS). Furthermore, we are designing experiments to facilitate the enzymatic process by means of a hydrated organic solvent matrix.
Date: December 15, 1988
Creator: Marquis, J.K. (Boston Univ., MA (United States). School of Medicine) & Kitchell, J.P. (Holometrix, Inc., Cambridge, MA (United States))
Object Type: Report
System: The UNT Digital Library
Frost as a first wall for the ICF Laboratory Microfusion Facility (open access)

Frost as a first wall for the ICF Laboratory Microfusion Facility

We introduce the concept of using frost as the first wall of the ICF Laboratory Microfusion Facility being designed to produce 200--1000 MJ of thermonuclear yield. We present one design incorporating 2 cm of frost deposited at 0.1 g/cm/sup 3/ on an LN-cooled fiber-reinforced polymer substrate. We calculate that such a frost layer will protect the substrate from ablation by target x rays and debris, and from shock-induced spallation. Postshot washdown with water should permit low-activation operation, and should preserve the original wall properties. We expect the impact of the frost on laser optics to be minimal, and expect the preshot lifetime of thermally unprotected cryogenic targets to be extended by operating the wall at 100-150 K. Moreover, we believe that such a frost first wall will involve little technical risk, and will be inexpensive to construct and operate. 4 refs., 1 fig.
Date: November 15, 1988
Creator: Orth, Charles D.
Object Type: Article
System: The UNT Digital Library
Reducing the RF Voltage Requirement by Blowing up the Initial Emittance (open access)

Reducing the RF Voltage Requirement by Blowing up the Initial Emittance

None
Date: September 15, 1988
Creator: Parzen, G.
Object Type: Report
System: The UNT Digital Library
A high luminosity B-/bar B/ factory: A research and development program (open access)

A high luminosity B-/bar B/ factory: A research and development program

In this paper we discuss a proposal for the construction of a high luminosity, L approx. 10/sup 34/cm/sup /minus/2/s/sup /minus/1/, electron-positron collider, operating in the energy range of 10 to 15 GeV total center of mass energy. The motivation for such a system is to study the physics of the B--/bar B/ system, in particular the rare decay modes and the CP violation. 4 refs., 1 fig., 4 tabs.
Date: October 15, 1988
Creator: Pellegrini, C. & Cline, D.
Object Type: Report
System: The UNT Digital Library
Compliant Converter Design and Analysis Study, Final Report on Phase 1 (open access)

Compliant Converter Design and Analysis Study, Final Report on Phase 1

No Abstract. There is a duplicate copy.
Date: February 15, 1988
Creator: Schock, Alfred
Object Type: Report
System: The UNT Digital Library
D0 Instrument Air System (open access)

D0 Instrument Air System

The main function of the instrument air system is to operate control valves associated with the cryogenics in the D0 hall. Occasionally, it will be used for purging purposes. Appendix A shows a schematic of the air instrument system along with a corresponding components list.
Date: September 15, 1988
Creator: Serges, T. J.
Object Type: Report
System: The UNT Digital Library
D-Zero Instrument Air System Humidity Transmitter Evaluation (open access)

D-Zero Instrument Air System Humidity Transmitter Evaluation

This report shows the findings that resulted in the purchase of the optimum dew point hygrometer for use in the D-Zero instrument air system (see diagram 2 on page 9). The hygrometer will monitor the air syste m to insure that the dew point level does not go above the normal operating output of the driers (this precise value will be determined during initial system start-up). The following criteria was used in the evaluation: (1) Long term durability; (2) Minimum calibration; (3) Indicate a dew point level down to -40 C accurately; (4) Designed to work in a low humidity region; (5) Minimum maintenance; (6) Fast response time; and (7) Lowest cost provided all other criteria is met.
Date: July 15, 1988
Creator: Serges, T. J.
Object Type: Report
System: The UNT Digital Library
Transverse Energy in nucleus-nucleus collisions: A review (open access)

Transverse Energy in nucleus-nucleus collisions: A review

The status of Transverse Energy (E/sub T/) in relativistic nucleus-nucleus collisions at the Brookhaven AGS and the CERN SPS is reviewed. The definition of E/sub T/ and its physical significance are discussed. The basic techniques and limitations of the experimental measurements are presented. The acceptances of the major experiments to be discussed are shown, along with remarks about their idiosyncrasies. The data demonstrate that the nuclear geometry of colliding spheres primarily determines the shapes of the observed spectra. Careful account of the acceptances is crucial to comparing and interpreting results. It is concluded that nuclear stopping power is high, and that the amount of energy deposited into the interaction volume is increasing with beam energy even at SPS energies. The energy densities believed to be obtained at the SPS are close to the critical values predicted for the onset of a quark-gluon plasma. 25 refs., 8 figs.
Date: November 15, 1988
Creator: Tincknell, M.
Object Type: Article
System: The UNT Digital Library
Ramping of solid iron analysis magnets in experimental areas: BM109 preliminary results (open access)

Ramping of solid iron analysis magnets in experimental areas: BM109 preliminary results

The long main ring TeV pulse period of 60 sec with a 20 sec flattop makes it attractive to ramp solid iron magnets, such as BM109's, etc., in synchronisms with the main ring pulse. Annual energy cost savings for a BM109 could be up to a maximum of $6.6 per hour or %58,000 per year. Are there 10 or more magnets we could ramp. What is the lag between the magnet excitation current and the magnet field. It is probably small because these magnets have large air gaps and therefore relatively short (short of one second) time constants. Some preliminary measurements showing the lag between the excitation current and the magnet field for a BM109 are included. Ramping BM109's seems practical if they are programmed up to 5 seconds ahead of the main ring pulse. Maybe ramping BM109's should be tried at a few locations to gain some experience. 4 figs.
Date: January 15, 1988
Creator: Visser, A.T.
Object Type: Report
System: The UNT Digital Library
Supercritical fluid thermodynamics for coal processing. Final report, September 15, 1988--September 14, 1991 (open access)

Supercritical fluid thermodynamics for coal processing. Final report, September 15, 1988--September 14, 1991

The main objective of this research is to develop an equation of state that can be used to predict solubilities and tailor supercritical fluid solvents for the extraction and processing of coal. To meet this objective we have implemented a two-sided. approach. First, we expanded the database of model coal compound solubilities in higher temperature fluids, polar fluids, and fluid mixtures systems. Second, the unique solute/solute, solute/cosolvent and solute/solvent intermolecular interactions in supercritical fluid solutions were investigated using spectroscopic techniques. These results increased our understanding of the molecular phenomena that affect solubility in supercritical fluids and were significant in the development of an equation of state that accurately reflects the true molecular makeup of the solution. (VC)
Date: September 15, 1988
Creator: van Swol, F. & Eckert, C. A.
Object Type: Report
System: The UNT Digital Library
Supercritical fluid thermodynamics for coal processing. Final report, September 15, 1988--September 14, 1991 (open access)

Supercritical fluid thermodynamics for coal processing. Final report, September 15, 1988--September 14, 1991

The main objective of this research is to develop an equation of state that can be used to predict solubilities and tailor supercritical fluid solvents for the extraction and processing of coal. To meet this objective we have implemented a two-sided. approach. First, we expanded the database of model coal compound solubilities in higher temperature fluids, polar fluids, and fluid mixtures systems. Second, the unique solute/solute, solute/cosolvent and solute/solvent intermolecular interactions in supercritical fluid solutions were investigated using spectroscopic techniques. These results increased our understanding of the molecular phenomena that affect solubility in supercritical fluids and were significant in the development of an equation of state that accurately reflects the true molecular makeup of the solution. (VC)
Date: September 15, 1988
Creator: van Swol, F. (Illinois Univ., Urbana, IL (United States). Dept. of Chemical Engineering) & Eckert, C.A. (Georgia Inst. of Tech., Atlanta, GA (United States). School of Chemical Engineering)
Object Type: Report
System: The UNT Digital Library