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A 0. 4 mm Interferometer System Using Dielectric Waveguide
A 0.4 mm submillimeter-wave, phase-modulated polarimeter/interferometer is used for simultaneous time-dependent measurement of line-averaged electron density and poloidal field-induced Faraday rotation along chords of the plasma column in ISX-B tokamak. Heterodyna detection and hollow dielectric waveguide are utilized to achieve the high sensitivity required for the multichord equipment.
Date:
January 1, 1982
Creator:
Hutchinson, D. P.; Ma, C. H.; Staats, P. A. & Vander Sluis, K. L.
System:
The UNT Digital Library
0. 9 a Gev /sup 238/U on /sup 238/U collisions in the LBL streamer chamber. Appendix A
Charged particle exclusive data for high multiplicity U on U events are reported. Analyses are based on comparison with Cugnon's intranuclear cascade model, and the explosion-evaporation simulation of Fai and Randrup. The azimuthal structure of the observed events shows evidence of collective flow. The widely used flow angle methodology proves to be relatively insensitive to collective effects under the conditions of the present experiment. An isotropic pattern of ejectile emission is not reached at maximum multiplicity. 18 refs., 4 figs.
Date:
January 1, 1984
Creator:
Fung, S.Y.; Beavis, D.; Gorn, W.; Keane, D.; Liu, Y.M.; Poe, R.T. et al.
System:
The UNT Digital Library
The 0/sup +/ /minus/ 1/sup +/ A = 4. lambda. -hypernuclei binding energy difference in an exact equation, separable potential calculation
None
Date:
January 1, 1988
Creator:
Gibson, B. F. & Lehman, D. R.
System:
The UNT Digital Library
0/sup -/ to 0/sup +/ beta decay in A = 16
Techniques and results of the measurement of the beta-decay rate of the first excited state of /sup 16/N to the ground state of /sup 16/O are reported. Energy levels involved in the decay are shown, and the /sup 16/N 0/sup -/ beta decay branching ration is given. (WHK)
Date:
January 1, 1982
Creator:
Gagliardi, C.; Garvey, G. T.; Wrobel, J. R. & Freedman, S. J.
System:
The UNT Digital Library
[1/2 HP Maytag Restoration]
Article by Pettinger, Wesley E. about 1/2 HP Maytag Engine Restoration.
Date:
January 13, 1997
Creator:
Pettinger, Wesley E.
System:
The UNT Digital Library
1. 5 GeV/c multiturn shaving extraction and its transport line for the Brookhaven AGS
A system for fast shaving extraction at 1.5 GeV/c is implemented to extract the circulating beam in five turns. A numerical simulation is first carried out to determine the emittance and the rf structure of the extracted beam. This is followed by several machine study sessions which establish the optimal extraction configuration, confirm the emittance, and modify the transport line for low energy beam. Finally, a one-week run for the Neutrino Oscillation experiment demonstrates that the system is very stable and capable of delivering 7.5 x 10/sup 12/ p/sec with 70% extraction efficiency and 95% transport efficiency.
Date:
January 1, 1979
Creator:
Weng, W. T.; Blumberg, L. N.; Gill, E.; Soukas, A.; Witkover, R. L.; Egleman, E. et al.
System:
The UNT Digital Library
1-D closure models for slender 3-D viscoelastic free jets: von Karman flow geometry and elliptical cross section
In this paper we derive one space dimensional, reduced systems of equations (1-D closure models) for viscoelastic free jets. We begin with the three-dimensional system of conservation laws and a Maxwell-Jeffreys constitutive law for an incompressible viscoelastic fluid. First, we exhibit exact truncations to a finite, closed system of 1-D equations based on classical velocity assumptions of von Karman. Next, we demonstrate that the 3-D free surface boundary conditions overconstrain these truncated systems, so that only a very limited class of solutions exist. We then proceed to derive approximate 1-D closure theories through a slender jet asymptotic scaling, combined with appropriate definitions of velocity, pressure and stress unknowns. Our nonaxisymmetric 1-D slender jet models incorporate the physical effects of inertia, viscoelasticity (viscosity, relaxation and retardation), gravity, surface tension, and properties of the ambient fluid, and include shear stresses and time dependence. Previous special 1-D slender jet models correspond to the lowest order equations in the present asymptotic theory by an a posteriori suppression to leading order of some of these effects, and a reduction to axisymmetry. Solutions of the lowest order system of equations in this asymptotic analysis are presented: For the special cases of elliptical inviscid and Newtonian free …
Date:
January 1, 1988
Creator:
Bechtel, S. E.; Forest, M. G.; Holm, D. D. & Lin, K. J.
System:
The UNT Digital Library
1-D hybrid code for FRM start-up
A one-D hybrid has been developed to study the start-up of the FRM via neutral-beam injection. The code uses a multi-group numerical model originally developed by J. Willenberg to describe fusion product dynamics in a solenoidal plasma. Earlier we described such a model for use in determining self-consistent ion currents and magnetic fields in FRM start-up. However, consideration of electron dynamics during start-up indicate that the electron current will oppose the injected ion current and may even foil the attempt to achieve reversal. For this reason, we have combined the multi-group ion (model) with a fluid treatment for electron dynamics to form the hybrid code FROST (Field Reversed One-dimensional STart-up). The details of this merger, along with sample results of operation of FROST, are given.
Date:
January 1, 1982
Creator:
Stark, R. A. & Miley, G. H.
System:
The UNT Digital Library
A 1-D model for highly sensitive tubular reactors
We consider the steady state operation of wall-cooled, fixed-bed tubular reactors. In these reactors the temperature rise ..delta..T must normally be limited to small fractions of the adiabatic temperature rise ..delta..T/sub ad/, both to avoid runaway and maintain product selectivity. Yet ..delta..T/..delta..T/sub ad/ << 1 can only occur if eta = t/sub dif//t/sub reac/ << 1, where t/sub dif/ is the timescale on which heat escapes the reactor by ''diffusing'' to the cooled walls, and t/sub reac/ is the timescale over which the reaction occurs. So here we use asymptotic methods based on eta << 1 to analyze the 2-d reactor equations, and find the radial concentration and temperature profiles to leading order in eta. We then obtain a 1-d model of the reactor by substituting these asymptotically correct profiles into the reactor equations and averaging over r. This model, the ..cap alpha..-model, is identical to the standard (Beek and Singer) 1-d model, except that the reactor's overall heat transfer coefficient U is a decreasing function of the temperature rise ..delta..T. This occurs because as ..delta..T increases, the reaction becomes increasingly concentrated near r = 0, causing a decreased heat transfer efficiency through the reactor's walls. By comparing it with …
Date:
January 1, 1987
Creator:
Hagan, P. S.; Herskowitz, M. & Pirkle, J. C.
System:
The UNT Digital Library
1 to 12 GeV/c beam transport for transverse or longitudinally polarized protons
A two-stage beam transport for polarized protons has been constructed and operated at the Argonne ZGS. The first stage delivers vertically polarized protons (N-type) to an elastic scattering polarimeter consisting of a 10 cm long LH/sub 2/ target and two moveable sets of forward and recoil scintillation counters. The unscattered protons transported through the beam's second stage are focused onto the polarized proton target PPT-III; this target utilizes a 2.5 T R and A magnet to produce target polarizations in the horizontal plane, either in the beam direction (L-type) or transverse to it (S-type). The second stage of the beam is equipped with a combination of superconducting solenoids and dipole magnets; thus the beam polarization can also be rotated to point in the L or S direction. The entire system has been operated successfully over the momentum range 1.0 to 11.75 GeV/c with NS, LS, SS, and LL beam target spin directions.
Date:
January 1, 1979
Creator:
Colton, E. P.
System:
The UNT Digital Library
2. 5 MeV neutron source for fission cross section measurement
A 2.5 MeV neutron source has been established on the beamline of a 100 kV, 0.5 ma ion accelerator. The ion accelerator provides a 100 kV deuteron beam of about 200 ..mu..a into a 3 mm beam spot at the target position. The neutron source is produced by the D(d,n)/sup 3/He reaction with a yield of about 10/sup 7/ n/sec. The time-correlated associated particle method (TCAP) is utilized for the neutron fluence determination and for neutron background elimination. The /sup 3/He associated particles are detected at 90 degrees behind a thin aluminum foil and the corresponding neutrons are emitted at 73.5 degrees with an energy near 2.5 MeV. Also, the protons from the competing D(d,p)T reaction are monitored at 135 degrees for normalization and diagnostic purposes. A fission chamber containing six uranium tetrafluoride deposits has been designed for use in the /sup 235/U(n,f) cross section measurement at 2.5 MeV. The 5 cm diameter deposits range in thickness from 230--300 ..mu..g/cm/sup 2/ and are expected to have good uniformity. A description of the 2.5 MeV neutron source facility is presented along with details of the associated particle detection and neutron beam characteristics. Preparations for the fission cross section measurement are discussed. …
Date:
January 1, 1988
Creator:
Duvall, K. C.; Wasson, O. A. & Ma, Honchang
System:
The UNT Digital Library
2. 05 x 10/sup 9/ age of the Oklo uranium deposit
U and Pb isotopic data on samples (10 to 100 gram) 2 to 10 m away from the borders of the Oklo reactor zones indicate a primary age of 2.05 x 10/sup 9/ years for the Oklo deposit and a secondary age of 0.375 x 10/sup 9/ years. All samples show effects of Pb loss; the average loss is 50 percent. Both the U--Pb and Pb isotopic data are consistent with a model of a primary 2.05 x 10/sup 9/ year age of the deposit, continuous volume diffusion of Pb from uraninite, and either continuous or recent loss of this Pb. In this case the 0.375 x 10/sup 9/ year age is an artifact without time significance. Using an average value of D/a/sup 2/ 3.5 x 10/sup -11/ a/sup -1/ (Cowan, this conference) this model explains the apparent 1.8 x 10/sup 9/ year Pb age observed by other workers. From the /sup 208/Pb//sup 206/Pb data the average U/Th value calculated for the Oklo deposit is approximately 100.
Date:
January 1, 1977
Creator:
Gancarz, A. J.
System:
The UNT Digital Library
2. 6/sup 0/K refrigeration system for CBA magnet testing
The superconducting magnets for the accelerator's rings will be cooled by a forced flow supercritical helium system from a central refrigeration plant. The design temperature for these magnets varies from 2.6 to 3.8/sup 0/K depending on a magnet's location in the ring. This paper describes the forced flow cooling system for testing a prototype magnet near 2.6/sup 0/K; this lowest temperature being of special interest to evaluate magnet quench protection. The test forced flow cooling system uses a three-stage approach, including an ejector pumped bath, similar to a cycle described previously. The coolant exists at 3.8/sup 0/K from these first stages and is then cooled further in a 64 cm diameter by 3 m high shielded liquid helium dewar. The supercritical helium gas passes through a submerged copper coil in this bath which is pumped to a pressure of 65 mm absolute by a screw compressor system. Temperatures are measured by thermistors located in the gas stream, and also embedded in the magnet coil.
Date:
January 1, 1982
Creator:
Bamberger, Joseph A.
System:
The UNT Digital Library
2-D and 3-D computations of curved accelerator magnets
In order to save computer memory, a long accelerator magnet may be computed by treating the long central region and the end regions separately. The dipole magnets for the injector synchrotron of the Advanced Photon Source (APS), now under construction at Argonne National Laboratory (ANL), employ magnet iron consisting of parallel laminations, stacked with a uniform radius of curvature of 33.379 m. Laplace's equation for the magnetic scalar potential has a different form for a straight magnet (x-y coordinates), a magnet with surfaces curved about a common center (r-{theta} coordinates), and a magnet with parallel laminations like the APS injector dipole. Yet pseudo 2-D computations for the three geometries give basically identical results, even for a much more strongly curved magnet. Hence 2-D (x-y) computations of the central region and 3-D computations of the end regions can be combined to determine the overall magnetic behavior of the magnets. 1 ref., 6 figs.
Date:
January 1, 1991
Creator:
Turner, L. R.
System:
The UNT Digital Library
2-D Eulerian hydrodynamics with fluid interfaces, self-gravity and rotation
The purpose of this paper is to describe in detail the numerical approach we have developed over the past five years for solving 2-dimensional gas-dynamical problems in astrophysics involving inviscid compressible flow, self-gravitation, rotation, and fluid instabilities of the Rayleigh-Taylor and Kelvin-Helmholtz types. The computer code to be described has been applied most recently to modeling jets in radio galaxies (Norman et al. 1981, 1982) and is an outgrowth of a code developed for studying rotating protostellar collapse (Norman, Wilson and Barton 1980; Norman 1980). This basic methodology draws heavily on the techniques and experience of James R. Wilson and James M. LeBlanc of the Lawrence Livermore National Laboratory, and thus the code is designed to be a general purpose 2-D Eulerian hydrocode, and is characterized by a high degree of simplicity, robustness, modularity and speed. Particular emphases of this article are: (1) the recent improvements to the code's accuracy through the use of vanLeer's (1977) monotonic advection algorithm, (2) a discussion of the importance of what we term consistent advection, and (3) a description of a numerical techique for modeling dynamic fluid interfaces in multidimensional Eulerian calculations developed by LeBlanc. 23 refs., 14 figs.
Date:
January 1, 1982
Creator:
Norman, M.L. & Winkler, K.H.A.
System:
The UNT Digital Library
S = -2 dibaryons and hypernuclei
Future prospects for the exploration of doubly strange hypernuclear systems are evaluated. Such systems may be produced via the double strangeness exchange reactions (K/sup -/,K/sup +/) or (K/sup -/,K/sup 0/) on nuclear targets. Theoretical estimates are given of the formation cross sections for Xi/sup -/ hypernuclear states via the one-step K/sup -/p ..-->.. K/sup +/Xi/sup -/ process, or discrete states of the ..lambda lambda.. hypernucleus in the two step reaction K/sup -/p ..-->.. ..pi../sup 0/..lambda.. followed by ..pi../sup 0/p ..-->.. K/sup +/..lambda... Recently, there has been much discussion of six quark (dibaryon) states in the Bag Model. Arguments are given which indicate that the (K/sup -/,K/sup +/) reaction on light nuclear targets (ex. /sup 3/He) affords a very promising way of producing the lowest-lying S = -2 dibaryon (called the H).
Date:
January 1, 1982
Creator:
Dover, C.B.
System:
The UNT Digital Library
N = 2 Maxwell-Einstein Supergravity Theories: Their Compact and Non-Compact Gaugings and Jordan Algebras
In this talk we give a review of our work on the construction and classification of N = 2 Maxwell-Einstein Supergravity theories (MESGT), study of the underlying algebraical and geometrical structure of these theories, and their compact and non-compact gaugings. We begin by summarizing our construction of the N = 2 MESGT's in five dimensions and give a geometrical interpretation to various scalar dependent quantities in the Lagrangian, based on the constraiants implied by supersymmetry. This is followed by a complete classification of the N = 2 MESGT's whose target manifolds parametrized by the scalar fields are symmetric spaces. 39 refs.
Date:
January 1, 1985
Creator:
Guenaydin, M.; Sierra, G. & Townsend, P.K.
System:
The UNT Digital Library
3. 6 simplified methods for design
Simplified design analysis methods for elevated temperature construction are classified and reviewed. Because the major impetus for developing elevated temperature design methodology during the past ten years has been the LMFBR program, considerable emphasis is placed upon results from this source. The operating characteristics of the LMFBR are such that cycles of severe transient thermal stresses can be interspersed with normal elevated temperature operational periods of significant duration, leading to a combination of plastic and creep deformation. The various simplified methods are organized into two general categories, depending upon whether it is the material, or constitutive, model that is reduced, or the geometric modeling that is simplified. Because the elastic representation of material behavior is so prevalent, an entire section is devoted to elastic analysis methods. Finally, the validation of the simplified procedures is discussed.
Date:
January 1, 1981
Creator:
Nickell, R.E. & Yahr, G.T.
System:
The UNT Digital Library
3-10 keV and 0. 1- to 2-MeV observations of four gamma-ray bursts
Four catalogued ..gamma..-ray bursts that occurred between 79/3/7 and 79/7/31 have been observed over the 3 to 10 keV range by a joint NRL/Los Alamos experiment on the Air Force P78-1 satellite. The bursts were also well observed by members of the interplanetary network. In this paper we present hardness ratios, x-ray/..gamma..-ray luminosity ratios, and time histories. The most significant results presented herein can be summarized as follows: (1) gamma-ray bursters can emit fairly strongly at x-ray energies near the time of the ..gamma.. burst with L/sub x//L/sub ..gamma../ approx. .02 (L/sub x/ approx. 10/sup 37/ ergs s/sup -1/, 3 to 10 keV, assuming a distance of 1 kpc); (2) the centroid of the x-ray emission generally lags the ..gamma..-ray centroid, but there is also evidence for one or more types of x-ray precursor activity; (3) the ..gamma..-ray hardness ratios were not highly variable for these particular events. However, there is some evidence that the ..gamma..-ray spectra softened near the ends of the bursts when the x-ray/..gamma..-ray ratios were high; (4) the x-ray/..gamma..-ray power law number index during times of the strongest ..gamma..-ray emission ranged from 0.8 to approx. 1.1 for the four bursts; (5) the x-ray tail of GB790307 …
Date:
January 1, 1983
Creator:
Laros, J. G.; Evans, W. D.; Fenimore, E. E.; Klebesadel, R. W.; Shulman, S. & Fritz, G.
System:
The UNT Digital Library
3-D Analysis on Arbitrarily-Shaped Icrf Antennas and Faraday Shields
Cavity antennas with Faraday shields are proposed to couple ion cyclotron radio frequency power for heating fusion plasmas. This application requires small, high-power, low-frequency antennas. The results are presented of a theoretical study of the ICRF antennas being developed for this purpose at the Radio Frequency Test Facility (RFTF). The objectives of this work are to optimize experimental designs and to confirm test results. (MOW)
Date:
January 1, 1986
Creator:
Chen, G. L.; Whealton, J. H.; Baity, F. W.; Hoffman, D. J. & Owens, T. L.
System:
The UNT Digital Library
3-D DETERMINISTIC TRANSPORT METHODS RESEARCH AT LANL UNDER ASCI
None
Date:
January 1, 2000
Creator:
Morel, J.
System:
The UNT Digital Library
A 3-D dynamical/chemical GCM for simulating the anthropogenical effects on ozone
In spite of the significantly increased attention atmospheric ozone has received over the last two decades or so, a fully quantitative understanding of the three-dimensional ozone structure remains unavailable. In the past, one-dimensional (vertical column) models have provided most of the quantitative simulations of atmospheric chemical systems, because these models can treat large ensembles of chemical process economically. More recently, two-dimensional (meridional cross section) models have become popular, in part because of increasing computer capabilities. There has been little work using a sophisticated 3-D GCM coupled with a comprehensive photochemical model to study the chemical-dynamical interactions involving the ozone abundance. Namely, either the dynamics or the chemistry is too simplified in most of the existing models. Relatively more advanced photochemistry has been included in the stratospheric models (dealing the vertical domain from 20 to 70 km above the surface) at the expense of tropospheric details. An important motivation for this research has been the desire to estimate the magnitude of changes in the ozone layer induced by anthropogenic perturbations such as the injection of oxides of nitrogen and chlorine compounds. Accordingly, the attempt has been to develop a complete but feasible photochemical scheme and to combine it with the Los …
Date:
January 1, 1989
Creator:
Kao, C. Y. J.; Glatzmaier, G. A.; Malone, R. C. & Turco, R. P.
System:
The UNT Digital Library
3-D heat transfer computer calculations of the performance of the IAEA's air-bath calorimeters
A three dimensional (3-D) heat transfer computer code was developed to study and optimize the design parameters and to better understand the performance characteristics of the IAEA's air-bath calorimeters. The computer model accounts for heat conduction and radiation in the complex materials of the calorimeter and for heat convection and radiation at its outer surface. The temperature servo controller is modelled as an integral part of the heat balance equations in the system. The model predictions will be validated against test data using the ANL bulk calorimeter. 11 refs., 6 figs.
Date:
January 1, 1989
Creator:
Elias, E.; Kaizermann, S.; Perry, R. B. & Fiarman, S.
System:
The UNT Digital Library
A 3-D hydrodynamic dispersion model for modeling tracer transport in Geothermal Reservoirs
A 3-D hydrodynamic dispersion model for tracer transport is developed and implemented into the TOUGH2 EOS3 (T2R3D) module. The model formulation incorporates a full dispersion tensor, based on a 3-D velocity field with a 3-D, irregular grid in a heterogeneous geological system. Two different weighting schemes are proposed for spatial average of 3-D velocity fields and concentration gradients to evaluate the mass flux by dispersion and diffusion of a tracer or a radionuclide. This new module of the TOUGH2 code is designed to simulate processes of tracer/radionuclide transport using an irregular, 3-D integral finite difference grid in non-isothermal, three-dimensional, multiphase, porous/fractured subsurface systems. The numerical method for this transport module is based on the integral finite difference scheme, as in the TOUGH2 code. The major assumptions of the tracer transport module are: (a) a tracer or a radionuclide is present and transported only within the liquid phase, (b) transport mechanisms include molecular diffusion and hydrodynamic dispersion in the liquid phase in addition to advection, and (c) first order decay and linear adsorption on rock grains are taken into account. The tracer or radionuclide is introduced as an additional mass component into the standard TOUGH2 formulation, time is discretized fully implicitly, …
Date:
January 26, 1998
Creator:
Wu, Yu-Shu & Pruess, Karsten
System:
The UNT Digital Library