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Gauge invariant actions for string models
String models of unified interactions are elegant sets of Feynman rules for the scattering of gravitons, gauge bosons, and a host of massive excitations. The purpose of these lectures is to describe the progress towards a nonperturbative formulation of the theory. Such a formulation should make the geometrical meaning of string theory manifest and explain the many ''miracles'' exhibited by the string Feynman rules. There are some new results on gauge invariant observables, on the cosmological constant, and on the symmetries of interacting string field theory. 49 refs.
Date:
June 1, 1986
Creator:
Banks, T.
Object Type:
Article
System:
The UNT Digital Library
Review and problem definition of water/rock reactions associated with injection of spent geothermal fluids from a geothermal plant into aquifers
Among the technical problems faced by the burgeoning geothermal industry is the disposal of spent fluids from power plants. Except in unusual circumstances the normal practice, especially in the USA, is to pump these spent fluids into injection wells to prevent contamination of surface waters, and possibly in some cases, to reduce pressure drawdown in the producing aquifers. This report is a survey of experience in geothermal injection, emphasizing geochemical problems, and a discussion of approaches to their possible mitigation. The extraction of enthalpy from geothermal fluid in power plants may cause solutions to be strongly supersaturated in various dissolved components such as silica, carbonates, sulfates, and sulfides. Injection of such supersaturated solutions into disposal wells has the potential to cause scaling in the well bores and plugging of the aquifers, leading to loss of injectivity. Various aspects of the geochemistry of geothermal brines and their potential for mineral formation are discussed, drawing upon a literature survey. Experience of brine treatment and handling, and the economics of mineral extraction are also addressed in this report. Finally suggestions are made on future needs for possible experimental, field and theoretical studies to avoid or control mineral scaling.
Date:
July 1, 1986
Creator:
Elders, W. A.
Object Type:
Report
System:
The UNT Digital Library
Radioactive materials released from nuclear power plants. Annual report, 1983. Volume 4
Releases of radioactive materials in airborne and liquid effluents from commercial light water reactors during 1983 have been compiled and reported. Data on solid waste shipments as well as selected operating information have been included. This report supplements earlier annual reports issued by the former Atomic Energy Commission and the Nuclear Regulatory Commission. The 1983 release data are summarized in tabular form. Data covering specific radionuclides are summarized.
Date:
August 1, 1986
Creator:
Tichler, J. & Norden, K.
Object Type:
Report
System:
The UNT Digital Library
Transport of intense ion beams. [HIBALL II]
The maximum transportable current for an ion beam is determined by considerations of focal strength, space charge equilibrium and stability, structural practically and emittance. These factors are described within the context of a heavy ion driver for Inertial Confinement Fusion. Recent supporting results from particle-in-cell simulations and transport experiments will be described.
Date:
June 1, 1986
Creator:
Lee, Edward P.
Object Type:
Article
System:
The UNT Digital Library
KMC unitarity and K/sup +/ yields. pi. /sup +/. nu. anti. nu
Experimental constraints on the Kobayashi-MaskawaCabibbo (KMC) matrix are surveyed and shown to provide a test of the standard model at the level of its O (..cap alpha..) radioactive corrections. The three generation prediction BR (K/sup +/ ..-->.. ..pi../sup +/..nu..) approx. = (0.35 approx. 3) x 10/sup 10/ is reviewed and the potential for enhancement up to approx. = 3 x 10/sup -9/ due to the fourth generation mixing is described. 19 refs.
Date:
June 1, 1986
Creator:
Marciano, William J.
Object Type:
Article
System:
The UNT Digital Library
Erosion and Redeposition Experiments in the PISCES Facility
The modification of surfaces during exposure to plasma bombardment is a critical issue in the development of limiter and wall materials for fusion confinement experiments. Controlled studies of the erosion and redeposition of materials during high flux and fluence plasma exposure are now possible in the PISCES facility. PISCES is a continuously operating plasma device which has achieved hydrogen plasma densities of over 10/sup 13/ cm/sup -3/ and electron temperatures of 5 to 24 eV over large areas. Ion fluxes of 10/sup 17/ to 10/sup 19/ cm/sup -2/ sec/sup -1/ and fluences of up to 10/sup 23/ cm/sup -2/ have been used to bombard biased samples inserted into the plasma. The plasma parameters can be selected to produce simple sputtering, or redeposition by the ionization and recycling of the sputtered target materials. Collaborative studies on the performance of Cu and Cu-Li alloys (with ANL), stainless steel (with SNLL), and graphite (with IPP at Garching, and SNLL) have been undertaken. Surface topography modification is always observed after a sufficient fluence is achieved. The net erosion rate is significantly lower during redeposition than one would expect from classical sputtering yields. The transport and deposition of different materials by the plasma to the …
Date:
May 1, 1986
Creator:
Goebel, D. M.; Hirooka, Y.; Conn, R. W.; Leung, W. K.; Campbell, G. A.; Bohdansky, J. et al.
Object Type:
Report
System:
The UNT Digital Library
Langmuir probe measurements in the TEXTOR tokamak during ALT-I pump limiter experiments
Langmuir probes have been used to characterize the edge plasma of the TEXTOR tokamak and measure the parameters of the plasma incident on the ALT-I pump limiter during ohmic and ICRH heating. Probes mounted directly on the ALT limiter, and a scanning probe located 90/sup 0/ toroidally from the limiter, provide data for the evaluation of pump limiter performance and its effect on the edge plasma. The edge plasma is characterized by density and flux e-folding lengths of about 1.8cm when ALT is the main limiter. These scrape-off lengths do not vary significantly as ALT is moved between the normal 42-46cm minor radii, but increase to over 2.2cm when ALT is inserted to 40cm. The flux to probes at a fixed position in the limiter shadow varies by less than 25% for core density changes of a factor of five. This suggests that the global particle confinement time tau/sub p/, scales as the core density. Estimates from the probes indicate that tau/sub p/ is on the order of the energy confinement time, tau/sub E/. The edge electron temperature, T/sub e/, typically decreases by a factor of two when the core density is raised from 1 to 4 x 10/sup 13/ …
Date:
April 1, 1986
Creator:
Goebel, D. M.; Campbell, G. A.; Conn, R. W.; Leung, W. K.; Dippel, K. H.; Finken, K. H. et al.
Object Type:
Report
System:
The UNT Digital Library
MEVVA ion source for high current metal ion implantation
The MEVVA (Metal Vapor Vacuum Arc) ion source is a new kind of source which can produce high current beams of metal ions. Beams of a wide range of elements have been produced, spanning the periodic table from lithium up to and including uranium. The source extraction voltage is up to 60 kV, and we are increasing this up to 120 kV. A total ion beam current of over 1 Ampere has been extracted from the present embodiment of the concept, and this is not an inherent limit. The ion charge state distribution varies with cathode material and arc current, and beams like Li/sup +/, Co/sup +,2+,3+/ and U/sup 3+,4+,5+,6+/ for example, are typical; thus the implantation energy can be up to several hundred kilovolts without additional acceleration. The ion source has potential applications for ion implantation and ion beam mixing for achievement of improved corrosion resistance or wear resistance in metals or surface modification of ceramic materials and semiconductors. Here we outline the source and its performance, and describe some very preliminary implantation work using this source.
Date:
July 1, 1986
Creator:
Brown, I. & Washburn, J.
Object Type:
Article
System:
The UNT Digital Library
Fate of accreting white dwarfs: Type I supernovae vs collapse
The final fate of accreting C + O white dwarfs is either thermonuclear explosion or collapse, if the white dwarf mass grows to the Chandrasekhar mass. We discuss how the fate depends on the initial mass, age, composition of the white dwarf and the mass accretion rate. Relatively fast accretion leads to a carbon deflagration at low central density that gives rise to a Type Ia supernova. Slower accretion induces a helium detonation that could be observed as a Type Ib supernova. If the initial mass of the C + O white dwarf is larger than 1.2 Msub solar, a carbon deflagration starts at high central density and induces a collapse of the white dwarf to form a neutron star. We examine the critical condition for which a carbon deflagration leads to collapse, not explosion. For the case of explosion, we discuss to what extent the nucleosynthesis models are consistent with spectra of Type Ia and Ib supernovae. 61 refs., 18 figs.
Date:
January 1, 1986
Creator:
Nomoto, Ken'ichi
Object Type:
Article
System:
The UNT Digital Library
Economic effects of hypothetical reductions in tree growth in the Northeastern and Southeastern United States
Objectives of this research were to review and critically evaluate economic methods and models for assessing the economic impacts of acid deposition-induced changes in forest productivity; to scope and assess the sensitivity of the potential economic impacts of changes in forest productivity; and to provide information and recommendations that will enhance Federal efforts to assess the economic impacts of acid deposition and to determine the benefits of alternative acid deposition mitigation and control strategies. A conceptual framework was developed for understanding and valuing the economic impacts of acid deposition-induced changes in forest productivity in markets for hardwood and softwood stumpage and the prducts made from this stumpage. Although the framework focuses on valuing the economic impacts of acid deposition, it could be used for any factor that causes changes in forest productivity. The scope of potential economic impacts due to changes in forest productivity was characterized. Based on this analysis, key methodological features were identified which would contribute substantially to providing accurate estimates of the economic damages caused by changes in forest productivity. These features served as the basis for identifying and critically evaluating existing models.
Date:
August 1, 1986
Creator:
Callaway, J.M.; Darwin, R.F. & Nesse, R.J.
Object Type:
Report
System:
The UNT Digital Library
Recent upgrading of the modelling program COMFORT
The computer code COMFORT, developed for the online control of machine functions at the SLC, has recently undergone several modifications to overcome some of its limitations. This note describes the reasons for these changes, the methods employed, some test results and the applications of the new version of the program.
Date:
September 2, 1986
Creator:
Hawkes, C. & Lee, M.
Object Type:
Report
System:
The UNT Digital Library
Growth and stability of Ag layers on Cu(110)
Combined surface science and high energy ion beam techniques have been used to characterize the composition, structure and thermal stability of Ag layers < 900A thick on Cu(110). A uniform Ag/Cu surface composite is formed for one monolayer coverage. Analysis of its growth with LEED shows that the Ag is initially confined to the (110) troughs and that further deposition results in a Ag(111) layer exhibiting c(2 x 4) symmetry. This surface science determination of Ag coverage is consistent with absolute coverages measured with Rutherford backscattering. Beyond one monolayer coverage, the deposition of Ag at 300K produces clustering (Stranski-Krastanov mechanism) in contrast to a poorly ordered but more uniform layering mode when deposited at 130K. Following nucleation for a deposition between one and two monolayers at 300K, Ag clusters approx.20 A thick grow laterally across the surface up to 5 or 6 monolayers deposition. Continuous films grown cold at thicknesses less than or equal to 115A are found to agglomerate above 500K exposing a tenacious Ag-Cu interface like that formed by one monolayer Ag deposition.
Date:
January 1, 1986
Creator:
Taylor, T. N.; Hoffbauer, M. A.; Maggiore, C. J. & Beery, J. G.
Object Type:
Article
System:
The UNT Digital Library
Impedance of a beam tube with antechamber
A beam vacuum chamber was proposed to allow synchrotron light to radiate from a circulating electron beam into an antechamber containing photon targets, pumps, etc. To determine the impedance such a geometry would present to the beam, electromagnetic measurements were carried out on a section of chamber using for low frequencies a current-carrying wire and for up to 16 GHz, a resonance perturbation method. Because the response of such a chamber would depend on upstream and downstream restrictions of aperture yet to be determined, the resonance studies were analyzed in some generality. The favorable conclusion of these studies is that the antechamber makes practically no contribution to either the longitudinal or the transverse impedances.
Date:
August 1, 1986
Creator:
Barry, W.; Lambertson, G.R. & Voelker, F.
Object Type:
Article
System:
The UNT Digital Library
Analysis of inelastic neutron scattering spectra from a time-of-flight spectrometer with filter detector
Inelastic neutron scattering spectra obtained from time-of-flight spectrometers with filter detector suffer in energy resolution from a long time-of-flight tail in the filter response function. A mathematical method is described which removes this tail in measured spectra. The energy resolution can thereby be adapted for each part of the spectrum. Applications of the method to data taken at the LANSCE pulsed spallation source are presented.
Date:
January 1, 1986
Creator:
Vorderwisch, P.; Mezei, F.; Eckert, J. & Goldstone, J.A.
Object Type:
Article
System:
The UNT Digital Library
1985 environmental monitoring report
The environmental monitoring program is designed to determine that BNL facilities operate such that the applicable environmental standards and effluent control requirements have been met. The data were evaluated using the appropriate environmental regulatory criteria. The environmental levels of radioactivity and other pollutants found in the vicinity of BNL during 1985 are summarized in this report. Detailed data are not included in the main body of the report, but are tabulated and presented in Appendix D. The environmental data include external radiation levels; radioactive air particulates; tritium concentrations; the amounts and concentrations of radioactivity in and the water quality of the stream into which liquid effluents are released; the water quality of the potable supply wells; the concentrations of radioactivity in biota from the stream; the concentrations of radioactivity in and the water quality of ground waters underlying the Laboratoy; concentrations of radioactivity in milk samples obtained in the vicinity of the Laboratory; and the 1984 strontium-90 data which was not available for inclusion in the 1984 Environmental Monitoring Report. In 1985, the results of the surveillance program demonstraed that the Laboratory has operated within the applicable environmental standards.
Date:
April 1, 1986
Creator:
Day, L.E.; Miltenberger, R.P. & Naidu, J.R. (eds.)
Object Type:
Report
System:
The UNT Digital Library
Predictive models for thermal hazards. [lowest constant surface temperature at which material of given size and shape will self-heat to catastrophic destruction]
Many self-heating accidents with energetic materials have occurred when operations that have been done safely on a small scale are attempted on a larger scale. They have also occurred when a material is heated for a longer time or to a higher temperature than is normal for its processing or storage, such as might be caused by equipment malfunction or power failure. To prevent self-heating accidents, we must be able to predict the critical temperature for the size and shape of the material we are interested in. The critical temperature is defined as the lowest constant surface temperature at which a material of a given size and shape will self-heat to catastrophic destruction. This can be burning, explosion, or detonation, and because it is related to heat flow, it is dependent on the geometry of the system. As size increases, the critical temperature decreases. The shape also affects the critical temperature, so that a sphere will have a higher critical temperature than any other shape with the same radius or half thickness. In this paper the authors discuss how the critical temperature can be calculated by the Frank-kamenetskii reactive-heat-flow equation for solid-state, unstirred systems, or by the Semenov equation for …
Date:
January 1, 1986
Creator:
Janney, J.L. & Rogers, R.N.
Object Type:
Report
System:
The UNT Digital Library
Nondestructive measurements in support of Waste Isolation Pilot Plant at Rockwell Hanford Operations: problems and methods
The 234-5Z Analytical Laboratory, located in the 200 West Area of the Hanford Site, has been requested to provide waste package measurement capability for both the Plutonium/Uranium Extraction (PUREX) Plant and Plutonium Finishing Plant (PFP) in support of the Waste Isolation Pilot Plant (WIPP) Waste Acceptance Criteria (WAC). The requested WIPP values are sensitive to changes in isotopic distribution. Unfortunately, the determination of the isotopic distribution of an individual waste item or drum is difficult. The problems and uncertainties encountered in providing the values are discussed. Also, examples of calculations for the WIPP-WAC are shown.
Date:
May 1, 1986
Creator:
Westsik, G.A.
Object Type:
Report
System:
The UNT Digital Library
Accelerator Technology Program. Status report, April-September 1985
This report presents highlights of major projects in the Accelerator Technology (AT) Division of the Los Alamos National Laboratory. Radio-frequency and microwave technology are dealt with. The p-bar gravity experiment, accelerator theory and simulation activities, the Proton Storage Ring, and the Fusion Materials Irradiation Test accelerator are discussed. Activities on the proposed LAMPF II accelerator, the BEAR (Beam Experiment Aboard Rocket) project, beam dynamics, the National Bureau of Standards racetrack microtron, and the University of Illinois racetrack microtron are covered. Papers published by AT-Division personnel during this reporting period are listed.
Date:
September 1, 1986
Creator:
Jameson, R.A. & Schriber, S.O. (comps.)
Object Type:
Report
System:
The UNT Digital Library
On-site waste storage assuring the success of on-site, low-level nuclear waste storage
Waste management has reached paramount importance in recent years. The successful management of radioactive waste is a key ingredient in the successful operation of any nuclear facility. This paper discusses the options available for on-site storage of low-level radioactive waste and those options that have been selected by the Department of Energy facilities operated by Martin Marietta Energy Systems, Inc. in Oak Ridge, Tennessee. The focus of the paper is on quality assurance (QA) features of waste management activities such as accountability and retrievability of waste materials and waste packages, retrievability of data, waste containment, safety and environmental monitoring. Technical performance and careful documentation of that performance are goals which can be achieved only through the cooperation of numerous individuals from waste generating and waste managing organizations, engineering, QA, and environmental management.
Date:
September 21, 1986
Creator:
Preston, E.L.
Object Type:
Article
System:
The UNT Digital Library
e/sup +/-e/sup -/ hadronic multiplicity distributions: negative binomial or Poisson
On the basis of fits to the multiplicity distributions for variable rapidity windows and the forward backward correlation for the 2 jet subset of e/sup +/e/sup -/ data it is impossible to distinguish between a global negative binomial and its generalization, the partially coherent distribution. It is suggested that intensity interferometry, especially the Bose-Einstein correlation, gives information which will discriminate among dynamical models. 16 refs.
Date:
January 1, 1986
Creator:
Carruthers, P. & Shih, C.C.
Object Type:
Article
System:
The UNT Digital Library
Review of the classical nova outburst
Observational studies have not only identified a new class of novae but theoretical simulations of this class have been found to be in excellent agreement with the observations. This new class consists of outbursts occurring on ONeMg white dwarfs in close binar systems in contrast to the other outbursts which are occurring on CO white dwarfs. We also review the effects of the ..beta../sup +/-unstable nuclei and show how their presence has a major effect on the evolution. 77 refs.
Date:
June 1, 1986
Creator:
Starrfield, S. & Sparks, W. M.
Object Type:
Article
System:
The UNT Digital Library
Diagnostics of the Los Alamos free-electron laser using streak systems
The applications of ''streak systems'' that provide time-resolved diagnostic data for the Los Alamos free-electron laser energy recovery experiments have been extended in the last year. We have used these systems with time resolutions of 10 ..mu..s, approx.20 ps, and 2 to 8 ps to address both macropulse and micropulse issues. As one example, the time-dependent extraction efficiency behavior during the macropulse is presented. In addition, the effects on the electron micropulse temporal shape of several accelerator parameters have been studied. These results include the evidence of electron beam peak currents that approach 200 A.
Date:
January 1, 1986
Creator:
Lumpkin, A. H. & Feldman, D. W.
Object Type:
Article
System:
The UNT Digital Library
Observation of KNO scaling in the neutral energy spectra from. cap alpha cap alpha. and pp collisions at ISR energies
Neutral transverse energy spectra in pp and ..cap alpha cap alpha.. interactions are analyzed in terms of the Wounded Nucleon Model. Analysis of the ..cap alpha cap alpha.. spectrum by application of a multiple nucleon-nucleon collision mechanism is conveniently performed when a Gamma Distribution is used to represent the pp spectral shape. The Wounded Nucleon Model provides a reasonable description of the ..cap alpha cap alpha.. spectrum for the first 3 orders of magnitude, but completely fails to account for the slope of the high energy tail of the distribution. However, the pp and ..cap alpha cap alpha.. spectra can both be fit to the same Gamma Distribution when scaled by their respective mean values and thus exhibit KNO scaling. 28 refs., 8 figs.
Date:
January 1, 1986
Creator:
Tannenbaum, Michael J.
Object Type:
Article
System:
The UNT Digital Library
Development of a continuous duty cryopump
The continuous output of large quantities of gases at low pressure from fusion reactors, principally helium and hydrogen isotopes, dictates the need for a high speed pumping system that operates continuously, efficiently, and automatically. A liquid helium-cooled cryopump operated by a microprocessor controller can meet these requirements. The prototype system described herein features a single cryopump with three distinct pumping units: two units for pumping the vacuum chamber arranged so that one unit is closed for regenerating while the other is pumping the chamber (100% redundancy); and a collector pump, which is a high speed cryopump for receiving the regenerated gas. The unit pumps deuterium but can be changed readily to a sorption pump for helium service.
Date:
June 1, 1986
Creator:
Sedgley, D. W.; Batger, T. H. & Call, W. R.
Object Type:
Report
System:
The UNT Digital Library