Study of intermittency in e sup + e sup minus annihilations at 29 GeV (open access)

Study of intermittency in e sup + e sup minus annihilations at 29 GeV

Charged particle multiplicity distributions from e{sup +}e{sup {minus}} annihilations at 29 GeV have been analyzed in selected rapidity and azimuthal angle intervals. The data were taken with the High Resolution Spectrometer at PEP. The factorial moments of the multiplicity distributions increase as the rapidity interval is decreased, the so-called intermittency phenomenon. These direct measurements of the moments agree with values derived from negative binomial fits to our multiplicity distributions in various central rapidity windows. The factorial moments are also given for the distribution in azimuthal angle around the beam direction and for the two-dimensional distribution in rapidity and azimuthal angle around the jet directions.
Date: June 15, 1990
Creator: Abachi, S.; Derrick, M.; Kooijman, P.; Musgrave, B.; Price, L.; Repond, J. et al.
Object Type: Article
System: The UNT Digital Library
Study of electron-positron interactions (open access)

Study of electron-positron interactions

For the past seven years, this group has been interested in the study of tests of the Standard Model of Electroweak interactions. The program has centered about the AMY experiment which examines the nature of the final state products in electron-positron collisions in the center of mass energy range near 60 GeV. Results of these measurements have shown a remarkable consistency with the predictions of the minimal model of 3 quark and lepton generations and single charged and neutral intermediate bosons. No new particles or excited states have been observed nor has any evidence for departures in cross sections or angular asymmetries from expectations been observed. These conclusions have been even more firmly established by the higher energy results from the LEP and SLC colliders at center of mass energies of about 90 GeV. Our focus is shifting to the neutrino as a probe to electroweak interactions. The relative merit of attempting to observe neutrinos from point sources versus observing neutrinos generally is not easy to predict. The improved ability to interpret is offset by the probably episodic nature of the emission and irreproducibility of the results. In this phase of development, it is best to be sensitive to both …
Date: September 15, 1990
Creator: Abashian, A.; Gotow, K. & Philonen, L.
Object Type: Report
System: The UNT Digital Library
Report of Foreign Research Assignment for M. M. Abraham, October 1989-September 1990 (open access)

Report of Foreign Research Assignment for M. M. Abraham, October 1989-September 1990

The traveler collaborated with M.J.M. Leask, J.M. Baker, B. Bleaney, and others at the Clarendon Laboratory, Oxford University, Oxford, UK, to Study Tetragonal rare-earth phosphates and vanadates by optical and magnetic spectroscopy. This work is related to similar studies that have been performed at ORNL by the Synthesis and Properties of Novel Materials Group in the Solid State Division.
Date: October 15, 1990
Creator: Abraham, M. M.
Object Type: Report
System: The UNT Digital Library
Quantitative non-destructive evaluation of high-temperature superconducting materials (open access)

Quantitative non-destructive evaluation of high-temperature superconducting materials

Even though the currently intensive research efforts on high-temperature superconducting materials have not yet converged on a well specified material, the strong indications are that such a material will be brittle, anisotropic, and may contain many flaws such as microcracks and voids at grain boundaries. Consequently, practical applications of high temperature superconducting materials will require a very careful strength analysis based on fracture mechanics considerations. Because of the high sensitivity of the strength of such materials to the presence of defects, methods of quantitative non-destructive evaluation may be expected to play an important role in strength determinations. This proposal is concerned with the use of ultrasonic methods to detect and characterize isolated cracks, clusters of microcracks and microcracks distributed throughout the material. Particular attention will be devoted to relating ultrasonic results directly to deterministic and statistical linear elastic fracture mechanics considerations.
Date: September 15, 1990
Creator: Achenbach, J. D.
Object Type: Report
System: The UNT Digital Library
Quantitative non-destructive evaluation of high-temperature superconducting materials. Technical progress report, September 1, 1989--August 30, 1990 (open access)

Quantitative non-destructive evaluation of high-temperature superconducting materials. Technical progress report, September 1, 1989--August 30, 1990

Even though the currently intensive research efforts on high-temperature superconducting materials have not yet converged on a well specified material, the strong indications are that such a material will be brittle, anisotropic, and may contain many flaws such as microcracks and voids at grain boundaries. Consequently, practical applications of high temperature superconducting materials will require a very careful strength analysis based on fracture mechanics considerations. Because of the high sensitivity of the strength of such materials to the presence of defects, methods of quantitative non-destructive evaluation may be expected to play an important role in strength determinations. This proposal is concerned with the use of ultrasonic methods to detect and characterize isolated cracks, clusters of microcracks and microcracks distributed throughout the material. Particular attention will be devoted to relating ultrasonic results directly to deterministic and statistical linear elastic fracture mechanics considerations.
Date: September 15, 1990
Creator: Achenbach, J. D.
Object Type: Report
System: The UNT Digital Library
ASSESS (Analytic System and Software for Evaluating Safeguards and Security) update: Current status and future developments (open access)

ASSESS (Analytic System and Software for Evaluating Safeguards and Security) update: Current status and future developments

The Analytic System and Software for Evaluating Safeguards and Security (ASSESS) has been released for use by DOE field offices and their contractors. In October, 1989, we offered a prototype workshop to selected representatives of the DOE community. Based on the prototype results, we held the first training workshop at the Central Training Academy in January, 1990. Four additional workshops are scheduled for FY 1990. ASSESS is a state-of-the-art analytical tool for management to conduct integrated evaluation of safeguards systems at facilities handling facilities. Currently, ASSESS focuses on the threat of theft/diversion of special nuclear material by insiders, outsiders, and a special form of insider/outsider collusion. ASSESS also includes a neutralization module. Development of the tool is continuing. Plans are underway to expand the capabilities of ASSESS to evaluate against violent insiders, to validate the databases, to expand the neutralization module, and to assist in demonstrating compliance with DOE Material Control and Accountability (MC A) Order 5633.3. These new capabilities include the ability to: compute a weighted average for performance capability against a spectrum of insider adversaries; conduct defense-in-depth analyses; and analyze against protracted theft scenarios. As they become available, these capabilities will be incorporated in our training program. ASSESS …
Date: July 15, 1990
Creator: Al-Ayat, R.A. (Lawrence Livermore National Lab., CA (USA)); Cousins, T.D. (USDOE, Washington, DC (USA)) & Hoover, E.R. (Sandia National Labs., Albuquerque, NM (USA))
Object Type: Article
System: The UNT Digital Library
Hadroproduction of charm at Fermilab E769 (open access)

Hadroproduction of charm at Fermilab E769

Experiment E769 at Fermilab obtained charm hadroproduction data during the 1987-88 Fixed Target running period with a 250 GeV hadron beam incident on thin target foils of Be, Al, Cu, and W. From an analysis of 25% of the recorded 400M trigger sample we have explored the Feynman x, p{sub t}{sup 2} and the atomic number dependence of charm quark production using samples of D{sup +} and D{sup 0} mesons. 7 refs., 4 figs.
Date: November 15, 1990
Creator: Alves, G. A.; Anjos, J. C.; de Mello Neto, J. R. T.; de Miranda, J. M.; da Motta, H.; dos Reis, A. C. et al.
Object Type: Article
System: The UNT Digital Library
Technical studies on a composite groundwater sample from F- and H-Area (open access)

Technical studies on a composite groundwater sample from F- and H-Area

A composite sample of groundwater from F- and H-Areas was collected by Waste Management Tech and delivered to the Savannah River Laboratory to use in preliminary experiments that would test three remediation technologies under consideration. The three technologies are pH adjustment and filtration, decontamination with a strong acid ion exchange resin, and decontamination with a chelating ion exchange resin.
Date: August 15, 1990
Creator: Bibler, J. P.
Object Type: Report
System: The UNT Digital Library
Technical studies on a composite groundwater sample from F- and H-Area (open access)

Technical studies on a composite groundwater sample from F- and H-Area

A composite sample of groundwater from F- and H-Areas was collected by Waste Management Tech and delivered to the Savannah River Laboratory to use in preliminary experiments that would test three remediation technologies under consideration. The three technologies are pH adjustment and filtration, decontamination with a strong acid ion exchange resin, and decontamination with a chelating ion exchange resin.
Date: August 15, 1990
Creator: Bibler, J. P.
Object Type: Report
System: The UNT Digital Library
Reflection mass spectrometry technique for monitoring and controlling composition during molecular beam epitaxy (open access)

Reflection mass spectrometry technique for monitoring and controlling composition during molecular beam epitaxy

This invention is comprised of a method for on-line accurate monitoring and precise control of molecular beam epitaxial growth of Groups III-III-V or Groups III-V-V layers in an advanced semiconductor device incorporates reflection mass spectrometry. The reflection mass spectrometry is responsive to intentional perturbations in molecular fluxes incident on a substrate by accurately measuring the molecular fluxes reflected from the substrate. The reflected flux is extremely sensitive to the state of the growing surface and the measurements obtained enable control of newly forming surfaces that are dynamically changing as a result of growth.
Date: August 15, 1990
Creator: Brennan, T. M.; Hammons, B. E. & Tsao, J. Y.
Object Type: Patent
System: The UNT Digital Library
Development of improved iron Fischer-Tropsch catalysts. Quarterly technical progress report, 1 October 1989--31 December 1989 (open access)

Development of improved iron Fischer-Tropsch catalysts. Quarterly technical progress report, 1 October 1989--31 December 1989

The objective of proposed research is development of catalysts with enhanced slurry phase activity and better selectivity to fuel range products, through a more detailed understanding and systematic studies of the effects of pretreatment procedures and promoters/binders (silica) on catalyst performance.
Date: January 15, 1990
Creator: Bukur, D. B. & Patel, S. A.
Object Type: Report
System: The UNT Digital Library
Development of improved iron Fischer-Tropsch catalysts (open access)

Development of improved iron Fischer-Tropsch catalysts

The objective of proposed research is development of catalysts with enhanced slurry phase activity and better selectivity to fuel range products, through a more detailed understanding and systematic studies of the effects of pretreatment procedures and promoters/binders (silica) on catalyst performance.
Date: January 15, 1990
Creator: Bukur, D.B. & Patel, S.A.
Object Type: Report
System: The UNT Digital Library
Electron-atom collision studies using optically state selected beams. Progress report, May 15, 1988--May 14, 1991 (open access)

Electron-atom collision studies using optically state selected beams. Progress report, May 15, 1988--May 14, 1991

This report discusses progress made during the current contract period on the authors research program to study collisions between spin-polarized electrons and spin-polarized atoms. The objective of this work is to stimulate a deeper theoretical understanding of the electron-atom interaction by providing the most complete possible experimental characterization of the colliding system. Through the use of optical state preparation techniques to prepare both the incident electrons and atom in well-defined initial states, the authors are able to extract substantially more information about the scattering process than is available from more conventional measurements of differential scattering cross sections. Their primary interest is to study in detail the role played by spin in electron-atom collisions at low to intermediate energies. The additional information provided by these spin-dependent measurements greatly enhances understanding of both exchange and the spin-orbit interaction in the scattering process. During this three-year period they have made substantial progress in measurements of both elastic and superelastic scattering of spin-polarized electrons from optically pumped sodium. The elastic scattering measurements in particular were made possible by several important improvements to the experimental apparatus.
Date: November 15, 1990
Creator: Celotta, R. J. & Kelley, M. H.
Object Type: Report
System: The UNT Digital Library
Superpressure Stratospheric Vehicle (open access)

Superpressure Stratospheric Vehicle

Our need for wide-band global communications, earth imaging and sensing, atmospheric measurements and military reconnaissance is extensive, but growing dependence on space-based systems raises concerns about vulnerability. Military commanders require space assets that are more accessible and under local control. As a result, a robust and low cost access to space-like capability has become a national priority. Free floating buoyant vehicles in the middle stratosphere can provide the kind of cost effective access to space-like capability needed for a variety of missions. These vehicles are inexpensive, invisible, and easily launched. Developments in payload electronics, atmospheric modeling, and materials combined with improving communications and navigation infrastructure are making balloon-borne concepts more attractive. The important milestone accomplished by this project was the planned test flight over the continental United States. This document is specifically intended to review the technology development and preparations leading up to the test flight. Although the test flight experienced a payload failure just before entering its assent altitude, significant data were gathered. The results of the test flight are presented here. Important factors included in this report include quality assurance testing of the balloon, payload definition and characteristics, systems integration, preflight testing procedures, range operations, data collection, and …
Date: September 15, 1990
Creator: Chocol, C.; Robinson, W. & Epley, L.
Object Type: Report
System: The UNT Digital Library
Circulation in gas-slurry column reactors (open access)

Circulation in gas-slurry column reactors

Circulation in bubble columns, such as those used in fischer-tropsch synthesis, detracts from their performance in that gas is carried on average more rapidly through the column, and the residence time distribution of the gas in the column is widened. Both of these factors influence mass-transfer operations in bubble columns. Circulation prediction and measurement has been undertaken using probes, one-dimensional models, laser Doppler velocimetry, and numerical modeling. Local void fraction was measured using resistance probes and a newly developed approach to determining air/water threshold voltage for the probe. A tall column of eight inch diameter was constructed of Plexiglas and the distributor plate was manufactured to distribute air evenly through the base of the column. Data were gathered throughout the volume at three different gas throughputs. Bubble velocities proved difficult to measure using twin probes with cross-correlation because of radial bubble movement. A series of three-dimensional mean and RMS bubble and liquid velocity measurements were also obtained for a turbulent flow in a laboratory model of a bubble column. These measurements have been made using a three-component laser Doppler velocimeter (LDV), to determine velocity distributions non-intrusively. Finally, the gas-liquid flow inside a vertically situated circular isothermal column reactor was simulated …
Date: August 15, 1990
Creator: Clark, N.; Kuhlman, J.; Celik, I.; Gross, R.; Nebiolo, E. & Wang, Yi-Zun.
Object Type: Report
System: The UNT Digital Library
Coal desulfurization in a rotary kiln combustor (open access)

Coal desulfurization in a rotary kiln combustor

BCR National Laboratory (BCRNL) has initiated a project aimed at evaluating the technical and economic feasibility of using a rotary kiln, suitably modified, to burn Pennsylvania anthracite wastes, co-fired with high-sulfur bituminous coal. Limestone will be injected into the kiln for sulfur control, to determine whether high sulfur capture levels can be achieved with high sorbent utilization. The principal objectives of this work are: (1) to prove the feasibility of burning anthracite refuse, with co-firing of high-sulfur bituminous coal and with limestone injection for sulfur emissions control, in a rotary kiln fitted with a Universal Energy International (UEI) air injector system; (2) to determine the emissions levels of SO{sub x} and NO{sub x} and specifically to identify the Ca/S ratios that are required to meet New Source Performance Standards; (3) to evaluate the technical and economic merits of a commercial rotary kiln combustor in comparison to fluidized bed combustors; and, (4) to ascertain the need for further work, including additional combustion tests, prior to commercial application, and to recommend accordingly a detailed program towards this end.
Date: August 15, 1990
Creator: Cobb, J. T., Jr.
Object Type: Report
System: The UNT Digital Library
Coal desulfurization in a rotary kiln combustor. Quarterly report No. 1, April 16, 1990--July 15, 1990 (open access)

Coal desulfurization in a rotary kiln combustor. Quarterly report No. 1, April 16, 1990--July 15, 1990

BCR National Laboratory (BCRNL) has initiated a project aimed at evaluating the technical and economic feasibility of using a rotary kiln, suitably modified, to burn Pennsylvania anthracite wastes, co-fired with high-sulfur bituminous coal. Limestone will be injected into the kiln for sulfur control, to determine whether high sulfur capture levels can be achieved with high sorbent utilization. The principal objectives of this work are: (1) to prove the feasibility of burning anthracite refuse, with co-firing of high-sulfur bituminous coal and with limestone injection for sulfur emissions control, in a rotary kiln fitted with a Universal Energy International (UEI) air injector system; (2) to determine the emissions levels of SO{sub x} and NO{sub x} and specifically to identify the Ca/S ratios that are required to meet New Source Performance Standards; (3) to evaluate the technical and economic merits of a commercial rotary kiln combustor in comparison to fluidized bed combustors; and, (4) to ascertain the need for further work, including additional combustion tests, prior to commercial application, and to recommend accordingly a detailed program towards this end.
Date: August 15, 1990
Creator: Cobb, J. T., Jr.
Object Type: Report
System: The UNT Digital Library
Search for resonant states in positron-electron scattering using a positron gas target (open access)

Search for resonant states in positron-electron scattering using a positron gas target

Narrow correlated positron-electron peaks discovered in superheavy nuclear collisions may be signatures for previously undetected neutral particle-like objects having masses of 1--2 MeV/c{sup 2}. We have designed an experiment to definitively test this hypothesis by searching for resonant states formed directly in the scattering of monoenergetic electrons incident on a gas of cold positrons confined magnetically in a Malmberg trap. This technique will provide a hundred-fold improvement in sensitivity to e{sup +}e{sup {minus}} resonances compared to previous positron-beam, thin-foil scattering experiments. Together with a recoil-shadow technique, this experiment will explore a five decade range in neutral-particle lifetimes (10{sup {minus}13}s to 10{sup {minus}8}s) which cannot be probed directly to other methods. 14 refs., 2 figs., 1 tab.
Date: October 15, 1990
Creator: Cowan, T. E.; Howell, R. H.; Rohatgi, R. R. (Lawrence Livermore National Lab., CA (USA)) & Fajans, J. (California Univ., Berkeley, CA (USA). Dept. of Physics)
Object Type: Article
System: The UNT Digital Library
High frequency CARM driver for RF linacs. Progress report, Year 1 (open access)

High frequency CARM driver for RF linacs. Progress report, Year 1

Progress during the first year of this program has been noteworthy in both theoretical and experimental areas. Substantial improvements to the MIT CARM codes have been carried out, and the code has been successfully benchmarked against other codes, linear theory, and experimental work. CARM amplifier phase stability has been studied theoretically and found to be significantly better than that of free-electron lasers or relativistic klystrons, provided the device is properly designed. Both multimode simulations and particle-in-cell simulations have been carried out to study mode competition effects between convectively unstable and absolutely unstable modes. Improvement of the Pierce-Wiggler code for modeling the beam formation prior to the interaction region has been carried out. Experimental designs for a long-pulse, modulator-driven CARM amplifier experiment which will be carried out by the end of this fiscal year have been mostly completed. Designs for an induction-linac-driven CARM amplifier experiment, which will be carried out by the end of Year II of this program,, have also been performed. Finally, a CARM oscillator experiment is presently underway at our facility.
Date: May 15, 1990
Creator: Danly, B. G.
Object Type: Report
System: The UNT Digital Library
Structural studies of complex carbohydrates of plant cell walls (open access)

Structural studies of complex carbohydrates of plant cell walls

Studies of the structures of complex carbohydrates in plant cell walls, continued. In particular, studies on oligosaccharides structure and activity are briefly presented. (SM)
Date: August 15, 1990
Creator: Darvill, A.
Object Type: Report
System: The UNT Digital Library
(International Thermonuclear Experimental Reactor support) (open access)

(International Thermonuclear Experimental Reactor support)

This report summarizes the activities under LLNL Purchase Order B089367, the purpose of which is to support the University/Lawrence Livermore National Laboratory Magnetic Fusion Program by evaluating the status of research relative to other national and international programs and assist in long-range plans and development strategies for magnetic fusion in general and for ITER in particular.'' Two specific subtasks are included: to review the LLNL Magnet Technology Development Program in the context of the International Thermonuclear Experimental Reactor Design Study'' and to assist LLNL to organize and prepare materials for an International Thermonuclear Experimental Reactor Design Study information meeting.''
Date: October 15, 1990
Creator: Dean, S. O.
Object Type: Report
System: The UNT Digital Library
Power supply control units for APS ring magnets (open access)

Power supply control units for APS ring magnets

The APS storage ring (1104 meters) is divided into 40 sectors. Each sector has 38 magnet coils in five magnet bases. Every alternate sector has an additional quadrupole magnet for skew correction. AR the main dipole magnets, two in each sector are connected in series and fed from one power supply unit. A base is controlled by one power supply control unit (PSCU). Each PSCU is connected to the host computer via a local area network (LAN). This note discusses the hardware configuration of the typical power supply control system used by the APS magnets and the software commands supported by the PSCU.
Date: April 15, 1990
Creator: Despe, O.D.
Object Type: Report
System: The UNT Digital Library
Photoinduced electron transfer reaction in zeolite cages (open access)

Photoinduced electron transfer reaction in zeolite cages

Research continued on photochemically induced electron transfer in zeolites. Reactions and synthesis of Ru(bpy){sub 3}{sup 2+} are discussed. Also, the intercalation properties of LiAl{sub 2}(OH){sub 6}{sup +}-X{sup {minus}} are being pursued. 5 figs. (CBS)
Date: January 15, 1990
Creator: Dutta, P. K.
Object Type: Report
System: The UNT Digital Library
Steam Gasification of Carbon: Catalyst Properties (open access)

Steam Gasification of Carbon: Catalyst Properties

The objectives of this research are to determine the catalyst composition and concentration for metal oxide (potassium and calcium oxides) catalyzed gasification of carbon. The scope of this research involves determining: the concentration of active catalytic sites (and thus the dispersion), at reaction conditions, as a function of temperature, carbon burnoff, catalyst loading, and catalyst type; the location of catalyst, on the surface, on an atomic scale; catalyst composition; the site-specific rate constant for steam gasification; insight into the reaction mechanism; and how to maximize catalyst dispersion. Isotope tracing will measure the concentration of active catalyst sites, their specific rate constant, and the dependence of sites on initial catalyst loading, carbon conversion (burnoff), and temperature. Transient isotope tracing, secondary ion mass spectrometry (SIMS), and scanning tunneling microscopy (STM), will be used to obtain a complete picture of the catalysts at reaction conditions. Carbon black, coal chars, and graphite will be used in the transient tracing experiment. In the SIMS and STM experiments, graphite and carbon deposited on a metal surface will be models of coal char.
Date: September 15, 1990
Creator: Falconer, J.L. & Lauderback, L.L.
Object Type: Report
System: The UNT Digital Library