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Evaluation of low activation vanadium alloys for structural material in a fusion reactor

Description: The V-7.2Cr-14.5Ti, V-9.2Cr-4.9Ti, V-9.9Cr-9.2Ti, V-13.5Cr-5.2Ti, V-4.1Cr-4.3Ti, Vanstar-7, V-4.6Ti, V-17.7Ti, and V-3.1Ti-(0.5-1.0)Si alloys were evaluated for use as structural material in a fusion reactor. The alloys were evaluated on the basis of their yield strength, swelling resistance, resistance to hydrogen and irradiation embrittlement, and compatibility with a lithium reactor coolant. On the basis of these evaluations, the V-7.2Cr-14.5Ti, V-9.2Cr-4.9Ti, V-9.9Cr-9.2Ti, V-13.5Cr-5.2Ti, … more
Date: October 23, 1989
Creator: Loomis, B. A.; Hull, A. B. & Smith, D. L.
Partner: UNT Libraries Government Documents Department
open access

Vacuum technology issues for the SSC (Superconducting Super Collider)

Description: The Superconducting Super Collider, to be built in Texas, will provide an energy of 40 TeV from colliding proton beams. This energy is twenty times higher than currently available from the only other cryogenic collider, the Fermilab Tevatron, and will allow experiments that can lead to a better understanding of the fundamental properties of matter. The energy scale and the size of the new machine pose intriguing challenges and opportunities for the its vacuum systems. The discussion will includ… more
Date: October 23, 1989
Creator: Joestlein, H.
Partner: UNT Libraries Government Documents Department
open access

Multipole Shimming of Permanent Magnets Using Harmonic CorrectorRings

Description: Shimming systems are required to provide sufficient fieldhomogeneity for high resolution NMR. In certain specialized applications,such as rotating-field NMR and portable (ex-situ) NMR, permanentmagnet-based shimming systems can provide considerable advantages. Wepresent a simple two-dimensional shimming method based on harmoniccorrector rings which can provide arbitrary multipole order shimmingcorrections. Results demonstrate, for example, that quadrupolar ordershimming improves the linewidth b… more
Date: October 23, 2006
Creator: Jachmann, Rebecca C.; Trease, David R.; Bouchard, Louis-S.; Sakellariou, Dimitris; Martin, Rachel W.; Schlueter, Ross D. et al.
Partner: UNT Libraries Government Documents Department
open access

An Alternative Model for Electron Correlation in Pu

Description: Using a density functional theory based approach that treats the 5f electrons relativistically, a Pu electronic structure with zero net magnetic moment is obtained, where the 5f orbital and 5f spin moments cancel each other. By combining the spin and orbital specific densities of states with state, spin and polarization specific transition moments, it is possible to reconstruct the experimentally observed photoemission spectra from Pu. Extrapolating to a spin-resolving Fano configuration, it is… more
Date: October 23, 2007
Creator: Yu, S.; Tobin, J. & Soderlind, P.
Partner: UNT Libraries Government Documents Department
open access

The Reactivity of Energetic Materials At Extreme Conditions

Description: Energetic materials are unique for having a strong exothermic reactivity, which has made them desirable for both military and commercial applications. Energetic materials are commonly divided into high explosives, propellants, and pyrotechnics. We will focus on high explosive (HE) materials here, although there is a great deal of commonality between the classes of energetic materials. Although the history of HE materials is long, their condensed-phase properties are poorly understood. Understan… more
Date: October 23, 2006
Creator: Fried, L E
Partner: UNT Libraries Government Documents Department
open access

Multiple-code simulation study of the long-term EDZ evolution of geological nuclear waste repositories

Description: This simulation study shows how widely different model approaches can be adapted to model the evolution of the excavation disturbed zone (EDZ) around a heated nuclear waste emplacement drift in fractured rock. The study includes modeling of coupled thermal-hydrological-mechanical (THM) processes, with simplified consideration of chemical coupling in terms of time-dependent strength degradation or subcritical crack growth. The different model approaches applied in this study include boundary ele… more
Date: October 23, 2008
Creator: Rutqvist, J.; Backstrom, A.; Chijimatsu, M.; Feng, X. T.; Pan, P. Z.; Hudson, J. et al.
Partner: UNT Libraries Government Documents Department
open access

LONGITUDINAL RESISTIVE INSTABILITIES OF INTENSE COASTING BEAMS IN PARTICLE ACCELERATORS

Description: The longitudinal electromagnetic interaction of an intense coasting beam with itself, including the effect of a resistive vacuum tank, is investigated theoretically. It is shown that even in the range where the particle frequency is an increasing function of particle energy, the beam can be longitudinally unstable due to the resistivity of the vacuum tank walls. In the absence of frequency spread in the unperturbed beam the beam is shown to be always unstable against longitudinal bunching with … more
Date: October 23, 1963
Creator: Neil, V. Kelvin & Sessler, Andrew M.
Partner: UNT Libraries Government Documents Department
open access

Genus Oblivious Cross Parameterization: Robust Topological Management of Inter-surface Maps

Description: We consider the problem of generating a map between two triangulated meshes, M and M{prime}, with arbitrary and possibly differing genus. This problem has rarely been tackled in its generality. Early schemes considered only topological spheres. Recent algorithms allow inputs with an arbitrary number of tunnels but require M and M{prime} to have equal genus, mapping tunnel to tunnel. Other schemes which allow more general inputs are not guaranteed to work and the authors do not provide a charact… more
Date: October 23, 2007
Creator: Bennett, J C; Pascucci, V & Joy, K I
Partner: UNT Libraries Government Documents Department
open access

Geometrically induced metastability and holography

Description: We construct metastable configurations of branes and anti-branes wrapping 2-spheres inside local Calabi-Yau manifolds and study their large N duals. These duals are Calabi-Yau manifolds in which the wrapped 2-spheres have been replaced by 3-spheres with flux through them, and supersymmetry is spontaneously broken. The geometry of the non-supersymmetric vacuum is exactly calculable to all orders of the't Hooft parameter, and to the leading order in 1/N. The computation utilizes the same matr… more
Date: October 23, 2006
Creator: Aganagic, Mina; Aganagic, Mina; Beem, Christopher; Seo, Jihye & Vafa, Cumrun
Partner: UNT Libraries Government Documents Department
open access

PASSIVITY BREAKDOWN AND EVOLUTION OF LOCALIZED CORROSION ON TYPE 316L STAINLESS STEEL

Description: Passivity breakdown of 316L SS in the presence of aggressive Cl{sup -} and inhibitive NO{sub 3}{sup -} anions has been experimentally studied and the results have been interpreted in terms of the Point Defect Model (PDM). By introducing the competitive adsorption of Cl{sup -} and NO{sub 3}{sup -} into surface oxygen vacancies at the passive film/solution interface, the PDM yields a critical breakdown potential (V{sub c}) that is predicted to vary linearly with log[Cl{sup -}], or with log ([Cl{s… more
Date: October 23, 2006
Creator: S. Yang, G. Engelhardt, and D. D. Macdonald
Partner: UNT Libraries Government Documents Department
open access

Final optics damage inspection (FODI) for the National Ignition Facility

Description: The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory (LLNL) will routinely fire high energy shots (approaching 10 kJ per beamline) through the final optics, located on the target chamber. After a high fluence shot, exceeding 4J/cm2 at 351 nm wavelength, the final optics will be inspected for laser-induced damage. The FODI (Final Optics Damage Inspection) system has been developed for this purpose, with requirements to detect laser-induced damage initiation and to t… more
Date: October 23, 2007
Creator: Conder, A.; Alger, T.; Azevedo, S.; Chang, J.; Glenn, S.; Kegelmeyer, L. et al.
Partner: UNT Libraries Government Documents Department
open access

Results from an International Simulation Study on Coupled Thermal,Hydrological, and Mechanical (THM) Processes near Geological NuclearWaste Repositories

Description: As part of the ongoing international DECOVALEX project, four research teams used five different models to simulate coupled thermal, hydrological, and mechanical (THM) processes near waste emplacement drifts of geological nuclear waste repositories. The simulations were conducted for two generic repository types, one with open and the other with back-filled repository drifts, under higher and lower postclosure temperatures, respectively. In the completed first model inception phase of the projec… more
Date: October 23, 2007
Creator: Rutqvist, Jonny; Rutqvist, J.; Barr, D.; Birkholzer, J.T.; Chijimatsu, M.; Kolditz, O. et al.
Partner: UNT Libraries Government Documents Department
open access

A comparative simulation study of coupled THM processes and their effect on fractured rock permeability around nuclear waste repositories

Description: This paper presents an international, multiple-code, simulation study of coupled thermal, hydrological, and mechanical (THM) processes and their effect on permeability and fluid flow in fractured rock around heated underground nuclear waste emplacement drifts. Simulations were conducted considering two types of repository settings: (a) open emplacement drifts in relatively shallow unsaturated volcanic rock, and (b) backfilled emplacement drifts in deeper saturated crystalline rock. The results … more
Date: October 23, 2008
Creator: Rutqvist, Jonny; Barr, Deborah; Birkholzer, Jens T.; Fujisaki, Kiyoshi; Kolditz, Olf; Liu, Quan-Shen et al.
Partner: UNT Libraries Government Documents Department
open access

New Phases of Hydrogen-Bonded Systems at Extreme Conditions

Description: We study the behavior of hydrogen-bonded systems under high-pressure and temperature. First principle calculations of formic acid under isotropic pressure up to 70 GPa reveal the existence of a polymerization phase at around 20 GPa, in support of recent IR, Raman, and XRD experiments. In this phase, covalent bonding develops between molecules of the same chain through symmetrization of hydrogen bonds. We also performed molecular dynamics simulations of water at pressures up to 115 GPa and 2000 … more
Date: October 23, 2006
Creator: Manaa, M R; Goldman, N & Fried, L E
Partner: UNT Libraries Government Documents Department
open access

Lawrence Livermore National Laboratory Two-Stage Light-Gas Gun

Description: The diagnostics and experimental program of a facility used to study condensed matter at high pressures are described.
Date: October 23, 1981
Creator: Mitchell, A. C.; Nellis, W. J. & Trainor, R. J.
Partner: UNT Libraries Government Documents Department
open access

Disruption control in tokamak reactors by electron-cyclotron current drive

Description: Launch scenarios for electron-cyclotron power into TIBER-II equilibria are presented. The power is absorbed outside the q = 2 flux surface, and the driven current significantly modifies the current profile, which may serve to suppress tearing-mode instabilities and prevent disruptions. A feedback-stabilization scheme may suppress the instabilities with very modest incident power. One of the launch scenarios is also effective for heating the plasma core during the startup phase. 15 refs., 4 figs. more
Date: October 23, 1987
Creator: Smith, G. R.; Logan, B. G.; Kritz, A. H. & White, R. B.
Partner: UNT Libraries Government Documents Department
open access

Extension of the EQ3/6 computer codes to geochemical modeling of brines

Description: Recent modifications to the EQ3/6 geochemical modeling software package provide for the use of Pitzer's equations to calculate the activity coefficients of aqueous species and the activity of water. These changes extend the range of solute concentrations over which the codes can be used to dependably calculate equilibria in geochemical systems, and permit the inclusion of ion pairs, complexes, and undissociated acids and bases as explicit component species in the Pitzer model. Comparisons of ca… more
Date: October 23, 1984
Creator: Jackson, K.J. & Wolery, T.J.
Partner: UNT Libraries Government Documents Department
open access

Loading capacity of various filters for lithium fire generated aerosols

Description: The lithium aerosol loading capacity of a prefilter, HEPA filters and a sand and gravel bed filter was determined. The test aerosol was characterized and was generated by burning lithium in an unlimited air atmosphere. Correlation to sodium aerosol loading capacities were made to relate existing data to lithium aerosol loadings under varying conditions. This work is being conducted in support of the fusion reactor safety program. The lithium aerosol was generated by burning lithium pools, up to… more
Date: October 23, 1980
Creator: Jeppson, D.W. & Barreca, J.R.
Partner: UNT Libraries Government Documents Department
open access

Improvement of Azimuthal Homogeneity in Permanent-Magnet Bearing Rotors

Description: Permanent magnets that are levitated and rotating over a bulk high-temperature superconductor (HTS) form the basis of many superconducting bearing designs. Experiments have shown that the rotational-loss coefficient of friction'' for thrust bearings of this type can be as low as 8 [times] 10[sup [minus]6]. While the loss mechanisms of such bearings are not well understood, the azimuthal homogeneity of the rotating permanent magnet is believed to play an important role in determining the loss. O… more
Date: October 23, 1992
Creator: Hull, J. R.; Rossing, T. D.; Mulcahy, T. M. & Uherka, K. L.
Partner: UNT Libraries Government Documents Department
open access

Symmetry issues in a class of ion beam targets using sufficiently short direct drive pulses

Description: Controlling asymmetries in direct drive ion beam targets depends upon the ability to control the effects of residual target asymmetries after an appropriate illumination scheme has already been utilized. A class of modified ion beam targets where residual asymmetries are ameliorated is considered. The illumination scheme used is an axially symmetric one convenient for reactor designs. Residual asymmetries are controlled by limiting the radial motion of the radius R/sub dep/ of peak ion energy d… more
Date: October 23, 1986
Creator: Mark, J.W.K. & Lindl, J.D.
Partner: UNT Libraries Government Documents Department
open access

Improvement of Azimuthal Homogeneity in Permanent-Magnet Bearing Rotors

Description: Permanent magnets that are levitated and rotating over a bulk high-temperature superconductor (HTS) form the basis of many superconducting bearing designs. Experiments have shown that the rotational-loss``coefficient of friction`` for thrust bearings of this type can be as low as 8 {times} 10{sup {minus}6}. While the loss mechanisms of such bearings are not well understood, the azimuthal homogeneity of the rotating permanent magnet is believed to play an important role in determining the loss. … more
Date: October 23, 1992
Creator: Hull, J. R.; Rossing, T. D.; Mulcahy, T. M. & Uherka, K. L.
Partner: UNT Libraries Government Documents Department
open access

Gas Pressure Forming of Titanium Alloys and Composites by Transformation Superplasticity

Description: By thermally cycling through their transformation temperature range, coarse-grained, polymorphic materials can be deformed superplastically, owing to the emergence of transformation mismatch plasticity (or transformation superplasticity) as a deformation mechanism. This mechanism is investigated under biaxial stress conditions during thermal cycling of unalloyed titanium, Ti-6Al-4V, and their composites (Ti/10 vol.% TiC{sub p}, Ti-6Al-4V/10 vol% TiC{sub p} and Ti-6Al-4V/5 vol.% TiB{sub w}). Dur… more
Date: October 23, 2001
Creator: Frary, M; Schuh, C & Dunand, D C
Partner: UNT Libraries Government Documents Department
open access

EVALUATION OF POTENTIAL ELUANTS FOR NON-ACID ELUTION OF CESIUM FROM SPHERICAL RESORCINOL-FORMALDEHYDE RESIN

Description: Ion Exchange column loading and elution of cesium from spherical resorcinol-formaldehyde resin have been conducted for two potential non-acid eluants -(NH{sub 4}){sub 2}CO{sub 3} and CH{sub 3}COONH{sub 4}. The results revealed encouraging cesium elution performance. 100% elution was achieved in at most 22 hours ({approx}28 bed volumes) of elution. Elution performance was fairly high at 6 hours ({approx}8 bed volumes) of elution for some of the eluants and also practically comparable to the benc… more
Date: October 23, 2011
Creator: Adu-Wusu, K.; Nash, C. & Pennebaker, F.
Partner: UNT Libraries Government Documents Department
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