Energy generation in convective shells of low mass, low metallicity stars (open access)

Energy generation in convective shells of low mass, low metallicity stars

We report on the non-negligible energy generation from the {sup 13}C neutron source and neutron capture reactions in low mass, low metallicity AGB stars. About 10{sup 4} L{sub {circle dot}} are generated within the thermal pulse convective shell by the combination of the {sup 13}C({alpha}, n){sup 16}O rate and the sum of the Y(Z,A)(n,{gamma})Y(Z,A + 1) reactions and beta decays. The inclusion of this energy source in an AGB thermal pulse evolution is shown to alter the evolution of the convective shell boundaries, and, hence, how the {sup 13}C is ingested into the convective shell. Also, the duration of the pulse itself is reduced by the additional energy input. The nucleosynthetic consequences are discussed for these evolutionary changes. 17 refs., 5 figs.
Date: November 10, 1989
Creator: Bazan, G. (Illinois Univ., Urbana, IL (USA). Dept. of Astronomy) & Lattanzio, J.C. (Lawrence Livermore National Lab., CA (USA))
Object Type: Article
System: The UNT Digital Library
Ionic alkali halide XUV laser feasibility study (open access)

Ionic alkali halide XUV laser feasibility study

The objective of this work is to assess the feasibility of a select set of ionic alkali halide XUV laser concepts by obtaining the relevant kinetic and spectroscopic parameters required for a proof-of-principle and conceptual design. The proposed lasers operate in the 80--200 nm spectral region and do not require input from outside radiation sources for their operation. Frequency up-conversion and frequency mixing techniques and therefore not considered in the work to be described. An experimental and theoretical study of a new type of laser operating in the extreme ultraviolet wavelength region has been conducted. The lasing species are singly ionized alkali halide molecules such as Rb{sup 2+}F{sub {minus}}, Rb{sup 2+}Br{sup {minus}} and Cs{sup 2+}F{sup {minus}}. These species are similar in electronic structure to the rare gas halide excimers, such as XeF and Krf, except that the ionic molecules emit at wavelengths of 80--200 nm, much shorter than the conventional rare-gas halide excimer laser. The radiative lifetime of these molecules are typically near 1 ns, which is about an order of magnitude shorter than that for rare-gas halide systems. The values of the cross section for stimulated emission are on the order of 1 {times} 10{sup {minus}16}cm{sup 2}. Because of …
Date: November 10, 1989
Creator: Yang, T. T.; Gylys, V. T.; Bower, R. D.; Harris, D. G.; Blauer, J. A.; Turner, C. E. et al.
Object Type: Report
System: The UNT Digital Library
Process Integration Study of the Decatur HFCS Plant for American Fructose Company, Decatur, AL [Advanced Industrial Heat Pump Applications and Evaluations] (open access)

Process Integration Study of the Decatur HFCS Plant for American Fructose Company, Decatur, AL [Advanced Industrial Heat Pump Applications and Evaluations]

This work has carried out in two phases: Phase 1, identification of opportunities for heat pumps in industrial applications and Phase 2; evaluation of heat pumps in industrial applications. In Phase 1, pinch analysis was applied to several industrial sites to identify the best opportunities for heat pumping and other forms of heat integration. In Phase 2, more detailed analyses were undertaken, including the evaluation of a heat pump installed as a recommendation of Phase 1.
Date: November 10, 1989
Creator: Eastwood, A.
Object Type: Report
System: The UNT Digital Library
The Temperature of the Cosmic Background Radiation: Results fromthe 1987 and 1988 Measurements at 3.8 GHz (open access)

The Temperature of the Cosmic Background Radiation: Results fromthe 1987 and 1988 Measurements at 3.8 GHz

We have measured the temperature of the cosmic background radiation (CBR) at a frequency of 3.8 GHz (7.9 cm wavelength), during two consecutive summers, obtaining a brightness temperature, T{sub CBR}, of 2.56 {+-} 0.08 K in 1987 and 2.71 {+-} 0.07 K in 1988 (68% confidence level). The new results are in agreement with our previous measurement at 3.7 GHz obtained in 1986, and have smaller error bars. Combining measurements from all three years we obtain T{sub CBR} = 2.64 {+-} 0.07 K.
Date: November 10, 1989
Creator: De Amici, Giovanni; Bensadoun, M.; Bersanelli, M.; Kogut, A.; Levine, S.; Smoot, George F. et al.
Object Type: Article
System: The UNT Digital Library
Longitudinal spin fluctuations in nickel (open access)

Longitudinal spin fluctuations in nickel

The longitudinal and transverse spin fluctuations in Ni have been measured below {Tc} by means of polarized neutron scattering in the momentum range 0.06 < q < 0.18 {angstrom}{sup -1}. In transverse scans spin wave peaks at E{sub q} = Dq{sup 2} appear as expected from early measurements performed with unpolarized neutrons. The longitudinal magnetic scattering {sub {chi}L}(q, E), on the other hand, is quasielastic without any signature of inelastic peaks near E{sub q}. The q and T dependences of {sub {chi}L}(q, E) resemble the paramagnetic scattering above {Tc}, i.e., the linewidth is roughly proportional to q{sup 2.5} and the integrated intensity I(q) is proportional to (q{sup 2} + {kappa}{sub z}{sup 2}){sup -1}. 8 refs., 3 figs.
Date: October 10, 1989
Creator: Boeni, P.; Martinez, J. L. & Tranquada, J. M.
Object Type: Article
System: The UNT Digital Library
Molten-Caustic-Leaching (Gravimelt) System Integration Project. Quarterly report, July--September 1989 (open access)

Molten-Caustic-Leaching (Gravimelt) System Integration Project. Quarterly report, July--September 1989

Operation of the Gravimelt Integrated Test Circuit for desulfurization and demineralization of coal has been completed. A 48-test process matrix was performed over 750 hours of operational time resulting in production of 3,000 pounds of treated coal suitable for further test and evaluation. Analysis of the several thousand data is underway. Assessment of coal material balance data shows an average 98% closure with 2% conversion of coal to humics and phenolics, 3% conversion to hydrogen and methane and 3 1/2% loss as carbonate. Assessment of sulfur forms data shows a mean residual pyritic sulfur of 0.022% for Pittsburgh No. 8 seam coal and 0.01% for Kentucky No. 9. Organic sulfur removal was dependent on conditions with lowest at 0.08% after processing in the plant. The mean sulfate sulfur level was 0.28% with a standard deviation of only 0.06%.
Date: October 10, 1989
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Upgrade of the Proton West secondary beamline (open access)

Upgrade of the Proton West secondary beamline

As originally designed and operated, protons entering PW6 were steered by a series of EPB dipoles into a single interaction length beryllium target, some 43 feet from the enclosure wall. Ensuing secondary beams, either p{sup +}/{pi}{sup +} or p{sup -}/{pi}{sup -}, were collected by a string of quadrupoles following the target, steered westward, away from the Proton Center line, through PW6 and PW7, and ultimately focussed on experiment production targets located within the large PW8 hall. Around the Spring of 1988 it was decided to upgrade the existing Proton West secondary beamline to allow for transport of a primary proton beam, anticipated to be either 800 or 900 GeV/c, through PW8. This upgrade project, which is now nearing completion, was largely motivated by the then recent approval of E-771, a hadronic beauty production experiment located in PW8. E-771 represents the third in a series of experiments for the large-acceptance dimuon spectrometer presently located at the end of the Proton West beamline. This Technical Memo is a summary of the upgrade --- an explanation of the underlying strategy and a documentation of the final locations of the secondary beamline elements. 6 refs., 2 figs., 2 tabs.
Date: October 10, 1989
Creator: Spiegel, L.
Object Type: Report
System: The UNT Digital Library
Inadequate neutron flux monitoring (open access)

Inadequate neutron flux monitoring

Reactor shutdown operations were outside the requirements of Technical Specification DPST-TS-105-2.1, Scram Instrumentation, and Technical Standard DPSTS-105-4.02, Subcritical Operations, when data was not recorded per DPSOL 105-1223B, Neutron Flux Control Monitoring During Shutdown -- External Fission Counter Normal Mode. DPSOL 105- 1223B, Data Sheet 2, requires operations personnel to record External Fission Counter (EFC) data at 15 minute intervals. Reactor Technology Department surveillance on 6/7/89 identified that data were not recorded for three consecutive intervals on 6/6/89. Operations personnel failed to take data per the frequency required in DPSOL 105-1223B. The time period that this event occurred was during shift change; the three missed readings should have been recorded at 7:15 a.m., and 7:45 a.m. Operations personnel were seated at the external fission counter desk and maintained audio/visual monitoring of the flux while conducting the turnover. Root Cause -- Monitoring alertness of personnel was less than adequate. Monitoring requirements for the external fission counters are set per DPSOL 105- 1223B. Personnel inadvertently failed to take data per the frequency required in DPSOL 105-1223B.
Date: August 10, 1989
Creator: Rubio, G. A.
Object Type: Report
System: The UNT Digital Library
New tools for the simulation and design of calorimeters (open access)

New tools for the simulation and design of calorimeters

Two new approaches to the simulation and design of large hermetic calorimeters are presented. Firstly, the Shower Library scheme used in the fast generation of showers in the Monte Carlo of the calorimeter for the D-Zero experiment at the Fermilab Tevatron is described. Secondly, a tool for the design future calorimeters is described, which can be integrated with a computer aided design system to give engineering designers an immediate idea of the relative physics capabilities of different geometries. 9 refs., 6 figs., 1 tab.
Date: July 10, 1989
Creator: Womersley, W.J.
Object Type: Article
System: The UNT Digital Library
Compendium of computer codes for the researcher in magnetic fusion energy (open access)

Compendium of computer codes for the researcher in magnetic fusion energy

This is a compendium of computer codes, which are available to the fusion researcher. It is intended to be a document that permits a quick evaluation of the tools available to the experimenter who wants to both analyze his data, and compare the results of his analysis with the predictions of available theories. This document will be updated frequently to maintain its usefulness. I would appreciate receiving further information about codes not included here from anyone who has used them. The information required includes a brief description of the code (including any special features), a bibliography of the documentation available for the code and/or the underlying physics, a list of people to contact for help in running the code, instructions on how to access the code, and a description of the output from the code. Wherever possible, the code contacts should include people from each of the fusion facilities so that the novice can talk to someone ''down the hall'' when he first tries to use a code. I would also appreciate any comments about possible additions and improvements in the index. I encourage any additional criticism of this document. 137 refs.
Date: March 10, 1989
Creator: Porter, G.D. (ed.)
Object Type: Report
System: The UNT Digital Library
Direct catalytic conversion of methane and light hydrocarbon gases. Quarterly report No. 9, October 1--December 31, 1988 (open access)

Direct catalytic conversion of methane and light hydrocarbon gases. Quarterly report No. 9, October 1--December 31, 1988

The goal of this research is to develop catalysts that directly convert methane and light hydrocarbons to intermediates that later can be converted to either liquid fuels or value-added chemicals, as economics dictate. During this reporting period, we completed our IR spectroscopic examination of the Ru{sub 4}/MgO and FeRu{sub 3}/MgO systems under nitrogen and methane by examining FeRu{sub 3}/MgO under methane. This system behaved quite differently than the same system under nitrogen. Under methane, only one very broad peak is observed at room temperature. Upon heating, the catalyst transformed so that by 300{degrees}C, the spectrum of FeRu{sub 3}/MgO under methane was the same as that of Ru{sub 4}/MgO. This suggests that methane promotes the segregation of the metals in the mixed metal system. The differences in catalytic activity between the FeRu{sub 3}/MgO and Ru{sub 4}/MgO systems may then be due to the presence of IR transparent species such as iron ions which cause different nucleation in the ruthenium clusters. We examined several systems for activity in the methane dehydrogenation reaction. Focusing on systems which produce C{sub 6} hydrocarbons since this is the most useful product. These systems all displayed low activity so that the amount of hydrocarbon product is very …
Date: March 10, 1989
Creator: Wilson, R. B., Jr.; Posin, B. M. & Chan, Yee Wai
Object Type: Report
System: The UNT Digital Library
High-average-power millimeter-wave FEL (free-electron laser) for plasma heating using the ETA-II accelerator (open access)

High-average-power millimeter-wave FEL (free-electron laser) for plasma heating using the ETA-II accelerator

The Microwave Tokamak Experiment (MTX) is under construction at LLNL to investigate the feasibility of intense, pulsed microwave radiation for plasma heating on future ignition tokamaks. A high-average-power free-electron laser (FEL) will use the Experimental Test Accelerator (ETA-II), a linear induction accelerator, in combination with an advanced high-field wiggler, to produce 1-2 MW of power at 1-2-mm wavelengths for periods of up to 0.5s. The design of the FEL, termed the intense microwave prototype (IMP), is described, along with the status and major issues associated with the status and major issues associated with the experiment. 10 refs., 8 figs., 4 tabs.
Date: March 10, 1989
Creator: Throop, A. L.; Atkinson, D. P.; Clark, J. C.; Deis, G. A.; Jong, R. A.; Nexsen, W. E. et al.
Object Type: Article
System: The UNT Digital Library
The dynamical behavior of classifier systems (open access)

The dynamical behavior of classifier systems

Classifier systems are quite complicated, in terms of both their components and behavior. This complexity is understandable given the wide spectrum of activity they are intended to model. Unfortunately, the complexity of these systems also makes it difficult to understand them analytically. Previous analysis has focused on specific components of the classifier system, for example, the genetic algorithm or the bucket brigade. The lack of a unified theory has led users of these systems to rely on ad hoc methods for choosing representations and parameter settings. Recent results (Riolo, 1988) indicate that classifier systems can be very sensitive to particular encodings and parameter choices. In this paper, we propose a methodology for studying the interactions among various components of the classifier system architecture.
Date: February 10, 1989
Creator: Forrest, S. & Miller, J.H.
Object Type: Article
System: The UNT Digital Library
Modular TPC's for relativistic heavy ion experiments (open access)

Modular TPC's for relativistic heavy ion experiments

We have developed a TPC system for use in relativistic heavy ion experiments that permits the efficient reconstruction of high multiplicity events including events with decay vertices. It operates with the beam through the middle of the chamber giving good efficiency, two-track separation and spatial resolution. The three-dimensional points in this system allow the reconstruction of the complex events of interest. The use of specially developed hybrid electronics allows us to build a compact and cost-effective system. 11 figs.
Date: February 10, 1989
Creator: Etkin, A.; Eiseman, S. E.; Foley, K. J.; Hackenburg, R. W.; Longacre, R. S.; Love, W. A. et al.
Object Type: Article
System: The UNT Digital Library
BNL glueball review (open access)

BNL glueball review

The glueball session of the BNL workshop on glueballs, hybrids and exotic hadrons is reviewed. This include studies of K/bar K/ , /eta/ , el/rho//degree/, , K/bar K/, /eta//eta/, /phi//phi/, /rho//rho/, , and K*/bar K/* resonances produced in elel, J//psi/, K/sup minus/p and /sup minus/p reactions. 44 refs., 5 figs., 4 tabs.
Date: December 10, 1988
Creator: Toki, W.H.
Object Type: Article
System: The UNT Digital Library
Resonance electronic Raman scattering in rare earth crystals (open access)

Resonance electronic Raman scattering in rare earth crystals

The intensities of Raman scattering transitions between electronic energy levels of trivalent rare earth ions doped into transparent crystals were measured and compared to theory. A particle emphasis was placed on the examination of the effect of intermediate state resonances on the Raman scattering intensities. Two specific systems were studied: Ce/sup 3 +/(4f/sup 1/) in single crystals of LuPO/sub 4/ and Er/sup 3 +/(4f/sup 11/) in single crystals of ErPO/sub 4/. 134 refs., 92 figs., 33 tabs.
Date: November 10, 1988
Creator: Williams, G.M.
Object Type: Report
System: The UNT Digital Library
Preliminary report confined tension testing of 900-24 (open access)

Preliminary report confined tension testing of 900-24

A specially designed confining pressure vessel is described that allows tensile samples to be tested under a superimposed confining hydrostatic pressure. Tests on samples of well characterized materials such as aluminum were used to verify the operation of the system, calibration of the internal load cell, and data reduction methods. The results of a series of exploratory tests done on the inert material 900-24 are described. 4 refs., 17 figs., 2 tabs.
Date: September 10, 1988
Creator: Harlow, R.A. & Browning, R.V.
Object Type: Article
System: The UNT Digital Library
Liquid Phase Methanol LaPorte PDU: Modification, Operation, and Support Studies (open access)

Liquid Phase Methanol LaPorte PDU: Modification, Operation, and Support Studies

To strengthen the data base of the Liquid Phase Methanol LaPorte technology, research is being conducted in parallel with the process development unit engineering and construction efforts. This work will address alternate liquid media studies, effects of CO{sub 2} in CO-rich synthesis gas, optimization of in-situ catalyst reduction and storage, catalyst poison studies, fundamental kinetic modelling, testing alternate commercial catalysts, and field testing of new guard-bed materials for catalyst poisons. Tests will be performed primarily using CO-rich synthesis gas. (VC)
Date: August 10, 1988
Creator: Brown, D. M. & Frank, M. E.
Object Type: Report
System: The UNT Digital Library
Liquid Phase Methanol LaPorte PDU: Modification, Operation, and Support Studies. Quarterly Technical Progress Report No. 4, 1 April--30 June 1988 (open access)

Liquid Phase Methanol LaPorte PDU: Modification, Operation, and Support Studies. Quarterly Technical Progress Report No. 4, 1 April--30 June 1988

To strengthen the data base of the Liquid Phase Methanol LaPorte technology, research is being conducted in parallel with the process development unit engineering and construction efforts. This work will address alternate liquid media studies, effects of CO{sub 2} in CO-rich synthesis gas, optimization of in-situ catalyst reduction and storage, catalyst poison studies, fundamental kinetic modelling, testing alternate commercial catalysts, and field testing of new guard-bed materials for catalyst poisons. Tests will be performed primarily using CO-rich synthesis gas. (VC)
Date: August 10, 1988
Creator: Brown, D. M. & Frank, M. E.
Object Type: Report
System: The UNT Digital Library
Heavy flavor production (open access)

Heavy flavor production

Predictions are presented of total cross sections for charm and bottom quark production in /bar p/p, ..pi../sup /minus//p, and pp interactions at fixed target and collider energies. The calculations are done through next-to-leading order in QCD perturbation theory. The sensitivity is explored of results to the choices of renormalization/evolution scale, parton densities, ..lambda../sub QCD/, and heavy flavor masses. Comparisons with available data show that good agreement is obtained for reasonable values of charm and bottom quark masses and other parameters. Open issues in the interpretation of results are summarized including the large size of the next-to-leading order contributions, proper definition of the gluon density, the nuclear A dependence of charm cross sections, the role of final state interactions, and higher twist effects. 39 refs., 7 figs., 5 tabs.
Date: June 10, 1988
Creator: Berger, E. L.
Object Type: Article
System: The UNT Digital Library
Radiation levels in the SSC interaction regions (open access)

Radiation levels in the SSC interaction regions

The radiation environment in a typical SSC detector has been evaluated using the best available particle production models coupled with Monte Carlo simulations of hadronic and electromagnetic cascades. The problems studied include direct charged particle dose, dose inside a calorimeter from the cascades produced by incident photons and hadrons, the flux of neutrons and photons backscattered from the calorimeter into a central cavity, and neutron flux in the calorimeter. The luminosity lifetime at the SSC is dominated by collision losses in the interaction regions, where the luminosity is equivalent to losing an entire full-energy proton beam into the apparatus every six days. The result of an average p-p collision can be described quite simply. The mean charged multiplicity is about 110, and the particles are distributed nearly uniformly in pseudorapidity ({eta}) over all the angles of interest. The transverse momentum distribution is independent of angle, and for our purposes may be written as p{perpendicular}exp(-p{perpendicular}/{beta}). The mean value of p{perpendicular} may be as high as 0.6 GeV/c. Most of the radiation is produced by the very abundant low-p{perpendicular} particles. The dose or neutron fluence produced by individual particles in this energy region are simulated over a wide variety of conditions, and …
Date: June 10, 1988
Creator: Groom, D.E.
Object Type: Report
System: The UNT Digital Library
Hadron collisions at TEV energies (open access)

Hadron collisions at TEV energies

This paper discusses the need for higher energy accelerators to probe the mysteries of the subatomic universe. Intermediate vector bosons are discussed as well as symmetry breaking and the standard model. (LSP)
Date: May 10, 1988
Creator: Cahn, R. N.
Object Type: Article
System: The UNT Digital Library
A survey of the current experimental database for lower hybrid current-drive and heating (open access)

A survey of the current experimental database for lower hybrid current-drive and heating

The proposed ITER design may rely heavily on Lower Hybrid waves to provide heating, current drive, MHD stabilization through current profile modification and transformer recharging. This paper presents a detailed survey of recent LH experimental results from PLT, Alcator C, ASDEX, Petula-B, FT and JT-60. Current drive and heating efficiencies are given, as well as regimes where sawteeth and m = 1 and 2 oscillations are stabilized. In addition, in ASDEX and JT-60, LH waves in combination with neutral beams, (a possible ITER scenario) experiments are examined. Finally, the current drive efficiency for ITER is obtained by extrapolating from the LHCD database. Assuming 12 MW of LH power, approximately 4.5 to 5.6 MA of current could be driven in ITER. However, the high density (/ovr /n///sub e/ = 8 /times/ 10/sup 19/ m/sup /minus/3/) and high temperature (/ovr/T///sub e/ = 21 keV) will preclude wave penetration to the center. Assuming a narrow N/sub /parallel// spectrum (1.2 /approx lt/ N/sub /parallel// /approx lt/ 2) the LH waves should be absorbed within the outer half of the plasma. 43 refs., 18 figs., 10 tabs.
Date: February 10, 1988
Creator: Blackfield, D. T.
Object Type: Article
System: The UNT Digital Library
What is the Emittance of the Injected Beam? (open access)

What is the Emittance of the Injected Beam?

None
Date: January 10, 1988
Creator: Parzen, G.
Object Type: Report
System: The UNT Digital Library