Resource Type

States

Comments on septa and other small production angle magnets (open access)

Comments on septa and other small production angle magnets

A discussion is given of possible septum magnet parameters for small production angle experiments in the ISABELLE storage rings. Superconducting septa and torroidal septa are also considered. (PMA)
Date: August 25, 1977
Creator: Allinger, J.; Danby, G. & Jackson, J.
System: The UNT Digital Library
A cryogenic system design for the international thermonuclear experimental reactor (ITER) (open access)

A cryogenic system design for the international thermonuclear experimental reactor (ITER)

A conceptual design for ITER was completed last year. The author developed a suitable cryogenic system for ITER as part of this conceptual design effort. An overview of the design is reported. Emphasis is on the fact that cryogenics is a mature science, and a system supporting ITER needs can be made from time-proven components without loss of efficiency or reliability. Because of the large size of the ITER cryogenic system, large numbers of compressors and expanders must be used. Very high reliability is assured by arranging these components in parallel banks where servicing of individual components can be done without interruption of operations. This and other ideas based on the author's experience with Mirror Fusion Test Facility (MFTF) operations are described. 5 refs., 3 figs.
Date: September 25, 1991
Creator: Slack, D.S.
System: The UNT Digital Library
Estimates of post-acceleration longitudinal bunch compression (open access)

Estimates of post-acceleration longitudinal bunch compression

A simple analytic method is developed, based on physical approximations, for treating transient implosive longitudinal compression of bunches of heavy ions in an accelerator system for ignition of inertial-confinement fusion pellet targets. Parametric dependences of attainable compressions and of beam path lengths and times during compression are indicated for ramped pulsed-gap lines, rf systems in storage and accumulator rings, and composite systems, including sections of free drift. It appears that for high-confidence pellets in a plant producing 1000 MW of electric power the needed pulse lengths cannot be obtained with rings alone unless an unreasonably large number of them are used, independent of choice of rf harmonic number. In contrast, pulsed-gap lines alone can meet this need. The effects of an initial inward compressive drift and of longitudinal emittance are included.
Date: November 25, 1977
Creator: Judd, D.L.
System: The UNT Digital Library
Viewgraph notes: geologic aspects of terminal storage of radioactive wastes (open access)

Viewgraph notes: geologic aspects of terminal storage of radioactive wastes

This document contains copies of viewgraphs discussed in a presentation made at the Fifth Annual Power Conference, August 29 to September 2, 1977. No text. 19 figures, 11 references.
Date: August 25, 1977
Creator: Lomenick, T.F.
System: The UNT Digital Library
Algebraic calculation of stroboscopic maps of ordinary, nonlinear differential equations (open access)

Algebraic calculation of stroboscopic maps of ordinary, nonlinear differential equations

The relation between the parameters of a differential equation and corresponding discrete maps are becoming increasingly important in the study of nonlinear dynamical systems. Maps are well adopted for numerical computation and several universal properties of them are known. Therefore some perturbation methods have been proposed to deduce them for physical systems, which can be modeled by an ordinary differential equation (ODE) with a small nonlinearity. A new iterative, rigorous algebraic method for the calculation of the coefficients of a Taylor expansion of a stroboscopic map from ODE's with not necessarily small nonlinearities is presented. It is shown analytically that most of the coefficients are small for a small integration time and grow slowly in the course of time if the flow vector field of the ODE is polynomial and if the ODE has fixed point in the origin. Approximations of different orders respectively of the rest term are investigated for several nonlinear systems. 31 refs., 16 figs.
Date: July 25, 1991
Creator: Wackerbauer, R. (Max-Planck-Institut fuer Extraterrestrische Physik, Garching (Germany)); Huebler, A. (Illinois Univ., Urbana, IL (United States). Center for Complex Systems Research) & Mayer-Kress, G. (Los Alamos National Lab., NM (United States) California Univ., Santa Cruz, CA (United States). Dept. of Mathematics)
System: The UNT Digital Library
Hybrid charged-particle guide for studying (n, charged particle) reactions (open access)

Hybrid charged-particle guide for studying (n, charged particle) reactions

Charged-particle transport systems consisting of magnetic quadrupole lenses have been employed in recent years in the study of (n, charged particle) reactions. We have completed a new transport system that is based both on magnetic lenses as well as electrostatic fields. The magnetic focusing of this charged-particle guide is provided by six magnetic quadrupole lenses arranged in a CDCCDC sequence (in the vertical plane). The electrostatic field is produced by a wire at high voltage which stretches the length of the guide and is physically at the center of the magnetic axis. The magnetic lenses are used for charged particles above 5 MeV; the electrostatic guide is used for lower energies. This hybrid system possesses the excellent focusing and background rejection properties of other magnetic systems. For low energy charged-particles, the electrostatic transport avoids the narrow band-passes in charged-particle energy which are a problem with purely magnetic transport systems. This system is installed at the LLNL Cyclograaff facility for the study of (n, charged particle) reactions at neutron energies up to 35 MeV.
Date: August 25, 1982
Creator: Haight, R. C.; White, R. M. & Zinkle, S. J.
System: The UNT Digital Library
Numerical simulation of the stability in a cable-in-conduit conductor developed for fusion-magnet applications (open access)

Numerical simulation of the stability in a cable-in-conduit conductor developed for fusion-magnet applications

The stability margins of the US-Demonstration Poloidal Coil (US-DPC) and the International Thermonuclear Experimental Reactor (ITER) TF coils have been modeled numerically using the computer program CICC. The computed US-DPC limiting current, I{sub lim}, compares favorably with the values determined experimentally. Using the detailed program CICC output, we investigated the DPC quench initiation mechanism in each of the three stability regions. In the ill-cooled region, the imposed heat pulse heats the conductor to the current-sharing temperature, T{sub cs}. In the transition region, the resistance heating after the pulse must be strong enough to overcome the induced flow reversal. In the well-cooled region, good heat transfer heats the helium during the pulse. After the pulse, these high helium temperatures along with poor heat transfer cause the conductor to quench. Changes in I{sub lim} agree with Dresner's relationship. I{sub lim} can be improved by decreasing the copper resistivity, the helium fraction, or the conductor diameter. Preliminary results show the ITER and TF coil operating point is in the well-cooled region. 10 refs., 7 figs., 1 tab.
Date: September 25, 1991
Creator: Wong, R.L.; Shen, S.S. (Lawrence Livermore National Lab., CA (United States)); Yeaw, C.T. (Wisconsin Univ., Madison, WI (United States)) & Miller, J.R. (National High Magnetic Field Laboratory, Florida State University (USA))
System: The UNT Digital Library
Time-dependent properties of fiber composites for energy-storage flywheels (open access)

Time-dependent properties of fiber composites for energy-storage flywheels

Time-dependent deformation and time-dependent strength are being characterized for several candidate polymeric composites for flywheels. This presentation highlights the motivation and the philosophy of the characterization adopted by the authors in establishing the ongoing programs at LLL. This overview is intended to provide a basis for inferring the type of enginering data being generated for different aspects of flywheel design. The details of these data can be obtained from the published reports and articles. Two aspects of flywheel design data are addressed: those dealing with time-dependent statistical strength, and those dealing with deformation and strength under time-varying history.
Date: October 25, 1977
Creator: Wu, E.M. & Penn, L.S.
System: The UNT Digital Library
Tritium experience at RTNS-II (open access)

Tritium experience at RTNS-II

Neutrons are produced at the Rotating Target Neutron Source-II (RTNS-II) by deuteron bombardment of a rotating tritium target. Tritium is released from these targets into the accelerator vacuum system. The vacuum system exhaust is first scrubbed and then vented via the facility stack. Tritium emission from the facility in normal operation with vacuum system exhaust flowing through the scrubber is extremely low, <1 mCi/day. Releases from by-passing the tritium scrubber during roughing of the vacuum system and from accelerator maintenance account for nearly all of the annual 10 Ci release from the facility. Routine target changes have been the cause of most tritium uptake by personnel. A target shipping system has been devised for transport of these targets.
Date: April 25, 1980
Creator: Logan, C. M.; Davis, J. C.; Gibson, T. A.; Heikkinen, D. W.; Schumacher, B. J. & Singh, M. S.
System: The UNT Digital Library
Production of muons for fusion catalysis in a magnetic mirror configuration. Revision 1 (open access)

Production of muons for fusion catalysis in a magnetic mirror configuration. Revision 1

For muon-catalyzed fusion to be of practical interest, a very efficient means of producing muons must be found. We describe a scheme for producing muons that may be more energy efficient than any heretofore proposed. There are, in particular, some potential advantages of creating muons from collisions of high energy tritons confined in a magnetic mirror configuration. If one could catalyze 200 fusions per muon and employ a uranium blanket that would multiply the neutron energy by a factor of 10, one might produce electricity with an overall plant efficiency (ratio of electric energy produced to nuclear energy released) approaching 30%. One possible near term application of a muon-producing magnetic-mirror scheme would be to build a high-flux neutron source for radiation damage studies. The careful arrangement of triton orbits will result in many of the ..pi../sup -/'s being produced near the axis of the magnetic mirror. The pions quickly decay into muons, which are transported into a small (few-cm-diameter) reactor chamber producing approximately 1-MW/m/sup 2/ neutron flux on the chamber walls, using a laboratory accelerator and magnetic mirror. The costs of construction and operation of the triton injection accelerator probably introduces most of the uncertainty in the viability of this …
Date: July 25, 1986
Creator: Moir, R.W. & Chapline, G.F. Jr.
System: The UNT Digital Library
Supernovae, compact stars and nuclear physics (open access)

Supernovae, compact stars and nuclear physics

We briefly review the current understanding of supernova. We investigate the implications of rapid rotation corresponding to the frequency of the new pulsar reported in the supernovae remnant SN1987A. It places very stringent conditions on the equation of state if the star is assumed to be bound by gravity alone. We find that the central energy density of the star must be greater than 12 times that of nuclear density to be stable against the most optimistic estimate of general relativistic instabilities. This is too high for the matter to plausibly consist of individual hadrons. We conclude that the newly discovered pulsar, if its half-millisecond signals are attributable to rotation, cannot be a neutron star. We show that it can be a strange quark star, and that the entire family of strange stars can sustain high rotation under appropriate conditions. We discuss the conversion of a neutron star to strange star, the possible existence of a crust of heavy ions held in suspension by centrifugal and electric forces, the cooling and other features. 39 refs., 8 figs., 2 tabs.
Date: August 25, 1989
Creator: Glendenning, N.K.
System: The UNT Digital Library
Current drive and heating systems for an ITER HARD option (open access)

Current drive and heating systems for an ITER HARD option

A conceptual design has been developed for a reference current drive and heating system for a HARD (High Aspect Ratio Design) option for ITER. Twelve neutral beam modules, each rated at 1.3MeV and 9.2MW, perform plasma heating and current drive. An electron cyclotron system is used for initiating the plasma and for disruption control. An alternate system has been defined which is comprised of a lower hybrid and ion cyclotron system for heating and current drive, augmented by the same electron cyclotron system proposed for the reference system. 7 refs., 8 figs., 1 tab.
Date: September 25, 1991
Creator: Lindquist, W.; Bulmer, R.; Fenstermacher, M.; Nevins, W.; Parker, J.; Smith, G. et al.
System: The UNT Digital Library
New tools using the hardware performance monitor to help users tune programs on the Cray X-MP (open access)

New tools using the hardware performance monitor to help users tune programs on the Cray X-MP

The performance of a Cray system is highly dependent on the tuning techniques used by individuals on their codes. Many of our users were not taking advantage of the tuning tools that allow them to monitor their own programs by using the Hardware Performance Monitor (HPM). We therefore modified UNICOS to collect HPM data for all processes and to report Mflop ratings based on users, programs, and time used. Our tuning efforts are now being focused on the users and programs that have the best potential for performance improvements. These modifications and some of the more striking performance improvements are described.
Date: September 25, 1991
Creator: Engert, D. E.; Rudsinski, L. (Argonne National Lab., IL (United States)) & Doak, J. (Cray Research, Inc., Minneapolis, MN (United States))
System: The UNT Digital Library
Mirror theory applied to toroidal systems (open access)

Mirror theory applied to toroidal systems

Central features of a mirror plasma are strong departures from Maxwellian distribution functions, ambipolar potentials and densities which vary along a field line, and losses, and the mirror field itself. To examine these features, mirror theorists have developed analytical and numerical techniques to solve the Fokker-Planck equation, evaluate the potentials consistent with the resulting distribution functions, and assess the microstability of these distributions. Various combinations of mirror-plasma fetures are present and important in toroidal plasmas as well, particularly in the edge region and in plasmas with strong r.f. heating. In this paper we survey problems in toroidal plasmas where mirror theory and computational techniques are applicable, and discuss in more detail three specific examples: calculation of the toroidal generalization of the Spitzer-Haerm distribution function (from which trapped-particle effects on current drive can be calculated), evaluation of the nonuniform potential and density set up by pulsed electron-cyclotron heating, and calculation of steady-state distribution functions in the presence of strong r.f. heating and collisions. 37 refs., 3 figs.
Date: August 25, 1987
Creator: Cohen, R.H.
System: The UNT Digital Library
Improving the injectability of high-salinity brines for disposal or waterflooding operations (open access)

Improving the injectability of high-salinity brines for disposal or waterflooding operations

This work is part of a study conducted by Lawrence Livermore National Laboratory (LLNL) to improve the performance of brine injection wells at Gulf Coast Strategic Petroleum Reserve Sites. Our involvement established that granular media filtration, when used with proper chemical pretreatments, provides an effective and economical method for removing particulates from hypersaline brines. This treatment allows for the injection of 200,000 B/D with significantly increased well half-lives of 30 years.
Date: July 25, 1981
Creator: Raber, E.; Thompson, R.E. & Smith, F.H.
System: The UNT Digital Library
The soudan 2 experiment (open access)

The soudan 2 experiment

Soudan 2 is an 1100-ton tracking calorimeter which is being constructed to search for nucleon decay. The detector consists of finely segmented iron instrumented with drift tubes, and records three spatial coordinates and dE/dx for every gas crossing. Excellent event-reconstruction capability, particle identification, and muon sign and direction determination give superior rejection of the neutrino background to nucleon decay in many modes. The first 275 tons of Soudan 2 is operating and a charged-particle test beam calibration is under way. Construction is scheduled for completion in 1992. 4 refs., 6 figs., 2 tabs.
Date: May 25, 1989
Creator: Ayres, D.S.
System: The UNT Digital Library
Cancer risks and neutron RBE's from Hiroshima and Nagasaki (open access)

Cancer risks and neutron RBE's from Hiroshima and Nagasaki

The new radiation dose estimates for Hiroshima and Nagasaki are radiobiologically examined for compatability with other human and experimental data. The new doses show certain improvements over the original T65 doses. However, they suggest for chronic granulocytic leukemia, total malignancies, and chromosome aberrations, at neutron doses of 1 rad, RBEs in excess of 100, higher than expected from other findings. This and other indications suggest that either there are unrecognized systematic problems with the various radiobiological data, or the new doses are deficient in neutrons for Hiroshima, by a factor of about five. If in fact there were actually some 5-fold more dose from neutrons at Hiroshima than estimated by the new calculations, the RBEs would agree well with laboratory results, and other inconsistencies would largely disappear. Cancer risks are estimated for neutrons from the new doses and are compared with those estimated from radiobiologically reconciled doses (the new doses adjusted by adding approximately 5-fold more neutrons). The latter appear more reasonable. For low-LET radiation, cancer risk estimates are changed very little by the new dose estimates for Nagasaki.
Date: March 25, 1982
Creator: Dobson, R.L. & Straume, T.
System: The UNT Digital Library
Isotherms for the uranium-hydrogen system at temperatures of 700 to 1065/sup 0/C and pressures to 137. 89 MPa (open access)

Isotherms for the uranium-hydrogen system at temperatures of 700 to 1065/sup 0/C and pressures to 137. 89 MPa

Pressure vs composition (P-C) isotherms for the UH system for temperatuers of 700 to 1065/sup 0/C and pressures to 137.89 MPa are shown. The sample was contained in a vessel concentric and located within a secondary vessel. Plateau pressure at 1065/sup 0/C is 700 atm. The single-phase region on the hydrogen-rich side starts at a H/U ratio of 2.35. Physical property measurements showed a thermal conductivity, k, value of 0.003 cal/cm sec K, R/sub c/ = 50. Experimentally determined plateau pressures are compared with values obtained by other workers. The UH system retains broad, two-phase plateaus at temperatures to 1065/sup 0/C. The critical temperature must be above 1065/sup 0/C. 13 refs., 3 figs., 1 tab.
Date: June 25, 1985
Creator: Lakner, J. F.
System: The UNT Digital Library
Hydrodynamic effects in evaporating droplets (open access)

Hydrodynamic effects in evaporating droplets

The vaporization of a spherically symmetric liquid droplet homogeneously heated by a high-intensity laser pulse is investigated on the basis of a hydrodynamic description of the system composed of the vapor and ambient gas. In the limit of convective vaporization, the boundary conditions at the fluid-gas interface are formulated by using the notion of a Knudsen layer across which translational equilibrium is established. Numerical solutions to the hydrodynamic equations exhibit the existence of two shock waves propagating in opposite directions with respect to the contact discontinuity that separates the ambient gas and vapor. 17 refs., 6 figs.
Date: September 25, 1986
Creator: Armstrong, R.L. & Zardecki, A.
System: The UNT Digital Library
Magnetic mirror fusion program (open access)

Magnetic mirror fusion program

The past, present, and future thrusts of the magnetic mirror fusion program at LLL are reviewed. Neutral beam injection, stabilization, and density-lifetime product results from the 2XIIB experiment are briefly highlighted. The rationale of the Tandem Mirror Experiment and Field Reversed Mirror Experiment now under way are discussed. Plans for the Mirror Fusion Test Facility (MFTF) are described. Approaches to improvement of particle containment in mirror fusion systems are briefly indicated. (RME)
Date: October 25, 1977
Creator: Fowler, T.K.
System: The UNT Digital Library
NFS, Kerberos, and UNICOS (open access)

NFS, Kerberos, and UNICOS

The Network File System (NFS) is used in UNIX-based networks to provide transparent file sharing between heterogeneous systems. Although NFS is well-known for being weak in security, it is widely used and has become a de facto standard. This paper examines the user authentication shortcomings of NFS and the approach Sandia National Laboratories has taken to strengthen it with Kerberos. The implementation on a Cray Y-MP8/864 running UNICOS is described and resource/performance issues are discussed. 4 refs., 4 figs.
Date: September 25, 1991
Creator: Haynes, R.A.
System: The UNT Digital Library
Effluent Treatment Facility tritium emissions monitoring (open access)

Effluent Treatment Facility tritium emissions monitoring

An Environmental Protection Agency (EPA) approved sampling and analysis protocol was developed and executed to verify atmospheric emissions compliance for the new Savannah River Site (SRS) F/H area Effluent Treatment Facility. Sampling equipment was fabricated, installed, and tested at stack monitoring points for filtrable particulate radionuclides, radioactive iodine, and tritium. The only detectable anthropogenic radionuclides released from Effluent Treatment Facility stacks during monitoring were iodine-129 and tritium oxide. This paper only examines the collection and analysis of tritium oxide.
Date: July 25, 1991
Creator: Dunn, D.L.
System: The UNT Digital Library
Selective extraction of copper, mercury, silver and palladium ionsfrom water using hydrophobic ionic liquids. (open access)

Selective extraction of copper, mercury, silver and palladium ionsfrom water using hydrophobic ionic liquids.

Extraction of dilute metal ions from water was performed near room temperature with a variety of ionic liquids. Distribution coefficients are reported for fourteen metal ions extracted with ionic liquids containing cations 1-octyl-4-methylpyridinium [4MOPYR]{sup +}, 1-methyl-1-octylpyrrolidinium [MOPYRRO]{sup +} or 1-methyl-1-octylpiperidinium [MOPIP]{sup +}, and anions tetrafluoroborate [BF{sub 4}]{sup +}, trifluoromethyl sulfonate [TfO]{sup +} or nonafluorobutyl sulfonate [NfO]{sup +}. Ionic liquids containing octylpyridinium cations are very good for extracting mercury ions. However, other metal ions were not significantly extracted by any of these ionic liquids. Extractions were also performed with four new task-specific ionic liquids. Such liquids containing a disulfide functional group are efficient and selective for mercury and copper, whereas those containing a nitrile functional group are efficient and selective for silver and palladium.
Date: June 25, 2007
Creator: Papaiconomou, Nicolas; Lee, Jong-Min; Salminen, Justin; VonStosch, Moritz & Prausnitz, John M.
System: The UNT Digital Library
A Cell-Centered Adaptive Projection Method for the IncompressibleNavier-Stokes Equations in Three Dimensions (open access)

A Cell-Centered Adaptive Projection Method for the IncompressibleNavier-Stokes Equations in Three Dimensions

We present a method for computing incompressible viscousflows in three dimensions using block-structured local refinement in bothspace and time. This method uses a projection formulation based on acell-centered approximate projection, combined with the systematic use ofmultilevel elliptic solvers to compute increments in the solutiongenerated at boundaries between refinement levels due to refinement intime. We use an L_0-stable second-order semi-implicit scheme to evaluatethe viscous terms. Results are presentedto demonstrate the accuracy andeffectiveness of this approach.
Date: September 25, 2007
Creator: Martin, D.F.; Colella, P. & Graves, D.T.
System: The UNT Digital Library