147 Matching Results

Search Results

Results: 1 - 24 next
open access

MFTF-B quasi-optical ECRH transmission system

Description: The microwave transmission system for ERCH on MFTF-B will utilize quasi-optical transmission techniques. The system consists of ten gyrotron oscillators: two gyrotrons at 28 GHz, two at 35 GHz, and six at 56 GHz. The 28 and 35 GHz gyrotrons both heat the electrons in the end plug (potential peak) while the 56 GHz sources heat the minimum-B anchor region (potential minimum). Microwaves are launched into a pair of cylindrical mirrors that form a pseudo-cavity which directs the microwaves through … more
Date: November 7, 1983
Creator: Yugo, J. J.; Shearer, J. W. & Ziolkowski, R. W.
Partner: UNT Libraries Government Documents Department
open access

Testing of developmental neutral beam sources for MFTF

Description: The design of a four-grid, spherically-focused, 10-by-46-cm area accelerator and ion source for the Mirror Fusion Test Facility (MFTF) has been previously described. This source was designed to operate at 80 kV-80 A for 0.5 s, and along with a matching, three-grid 20-kV-100-A-10-ms accelerator, has been built and tested. The 80-kV source has operated beyond design specifications to 90 kV-90 A for 12 ms. Pulse duration was limited by a capacitor bank accelerator power supply. Tests to 0.5 s on t… more
Date: November 7, 1979
Creator: Molvik, A.W.
Partner: UNT Libraries Government Documents Department
open access

COMPARISONS OF CRYSTALLINE SILICOTITANATE AND RESORCINOL FORMALDEHYDE MEDIA FOR CESIUM REMOVAL BY IN-TANK COLUMN PROCESSING

Description: Chemical and thermal performance of crystalline silicotitanate (CST) and resorcinol-formaldehyde (RF) ion exchange media were predicted for column configurations designed for installation in high level waste tanks and intended for cesium removal from radioactive waste supernates. Modeling predictions for the processing of a known Savannah River Site tank waste composition were generated. In a two column configuration under presumed nominal operating conditions (432 gallon packed bed, 10 gpm liq… more
Date: November 7, 2007
Creator: King, W; Frank02 Smith, F; Si Lee, S & Daniel McCabe, D
Partner: UNT Libraries Government Documents Department
open access

Targeting the tumor microenvironment

Description: Despite some notable successes cancer remains, for the most part, a seemingly intractable problem. There is, however, a growing appreciation that targeting the tumor epithelium in isolation is not sufficient as there is an intricate mutually sustaining synergy between the tumor epithelial cells and their surrounding stroma. As the details of this dialogue emerge, new therapeutic targets have been proposed. The FDA has already approved drugs targeting microenvironmental components such as VEGF a… more
Date: November 7, 2006
Creator: Kenny, P. A.; Lee, G. Y. & Bissell, M. J.
Partner: UNT Libraries Government Documents Department
open access

The Extinction Toward the Galactic Bulge from RR Lyrae Stars

Description: The authors present mean reddenings toward 3525 RR0 Lyrae stars from the Galactic bulge fields of the MACHO Survey. These reddenings are determined using the color at minimum V-band light of the RR0 Lyrae stars themselves and are found to be in general agreement with extinction estimates at the same location obtained from other methods. Using 3256 stars located in the Galactic Bulge, they derive the selective extinction coefficient R{sub V,VR} = A{sub V}/E(V-R) = 4.2 {+-} 0.2. this value is wha… more
Date: November 7, 2007
Creator: Kunder, A.; Popowski, P.; Cook, K. & Chaboyer, B.
Partner: UNT Libraries Government Documents Department
open access

Passive Spectroscopy Bolometers, Grating- And X-Ray Imaging Crystal Spectrometers

Description: This tutorial gives a brief introduction into passive spectroscopy and describes the working principles of bolometers, a high-resolution grating spectrometer, and a novel X-ray imaging crystal spectrometer, which is of particular interest for profile measurements of the ion temperature and plasma rotation velocity on ITER and future burning plasma experiments.
Date: November 7, 2007
Creator: Bitter, M.; Hill, K. W.; Scott, S.; Paul, S.; Ince-Cushmann, A.; Reinke, M. et al.
Partner: UNT Libraries Government Documents Department
open access

Electronic Excitations and Metal-Insulator Transition inPoly(3-hexylthiophene) Organic Field-Effect Transistors

Description: We carry out a comprehensive theoretical and experimentalstudy of charge injection in poly(3-hexylthiophene) (P3HT) to determinethe most likely scenario for metal-insulator transition in this system.Wecalculate the optical-absorption frequencies corresponding to a polaronand a bipolaron lattice in P3HT. We also analyze the electronicexcitations for three possible scenarios under which a first- or asecond-order metal-insulator transition can occur in doped P3HT. Thesetheoretical scenarios are co… more
Date: November 7, 2006
Creator: Sai, N.; Li, Z.Q.; Martin, M.C.; Basov, D.N. & Di Ventra, M.
Partner: UNT Libraries Government Documents Department
open access

Telomere dysfunction and cell survival: roles for distinctTIN2-containing complexes

Description: Telomeres are maintained by three DNA binding proteins, TRF1, TRF2 and POT1, and several associated factors. One factor, TIN2, binds TRF1 and TRF2 directly and POT1 indirectly. These and two other proteins form a soluble complex that may be the core telomere-maintenance complex. It is not clear whether subcomplexes exist or function in vivo. Here, we provide evidence for two TIN2 subcomplexes with distinct functions in human cells. TIN2 ablation by RNA interference caused telomere uncapping and… more
Date: November 7, 2006
Creator: Kim, Sahn-Ho; Davalos, Albert R.; Heo, Seok-Jin; Rodier, Francis; Beausejour, Christian; Kaminker, Patrick et al.
Partner: UNT Libraries Government Documents Department
open access

Robustness Studies of Ignition Targets for the National Ignition Facility in Two Dimensions

Description: Inertial confinement fusion capsules are critically dependent on the integrity of their hot spots to ignite. At the time of ignition, only a certain fractional perturbation of the nominally spherical hot spot boundary can be tolerated and the capsule still achieve ignition. The degree to which the expected hot spot perturbation in any given capsule design is less than this maximum tolerable perturbation is a measure of the ignition margin or robustness of that design. Moreover, since there will… more
Date: November 7, 2007
Creator: Clark, D S; Haan, S W & Salmonson, J D
Partner: UNT Libraries Government Documents Department
open access

Predictive three dimensional modeling of Stimulated Brillouin Scattering in ignition-scale experiments

Description: The first three-dimensional (3D) simulations of a high power 0.351 {micro}m laser beam propagating through a high temperature hohlraum plasma are reported. We show that 3D linear kinetic modeling of Stimulated Brillouin scattering reproduces quantitatively the experimental measurements, provided it is coupled to detailed hydrodynamics simulation and a realistic description of the laser beam from its millimeter-size envelop down to the micron scale speckles. These simulations accurately predict … more
Date: November 7, 2007
Creator: Divol, L; Berger, R; Meezan, N; Froula, D H; Dixit, S; Suter, L et al.
Partner: UNT Libraries Government Documents Department
open access

Demonstrating fractal scaling of residence time distributions on the catchment scale using a fully-coupled, variably-saturated groundwater and land surface model and a Lagrangian particle tracking approach

Description: The influence of the vadose zone, land surface processes, and macrodispersion on scaling behavior of residence time distributions (RTDs) is studied using a fully coupled watershed model in conjunction with a Lagrangian, particle-tracking approach. Numerical experiments are used to simulate groundwater flow paths from recharge locations along the hillslope to the streambed. These experiments are designed to isolate the influences of topography, vadose zone/land surface processes, and macrodisper… more
Date: November 7, 2007
Creator: Kollet, S J & Maxwell, R M
Partner: UNT Libraries Government Documents Department
open access

Simple Model Representations of Transport in a Complex Fracture and Their Effects on Long-Term Predictions

Description: A complex fracture model for fluid flow and tracer transport was previously developed that incorporates many of the important physical effects of a realistic fracture, including advection through a heterogeneous fracture plane, partitioning of flow into multiple subfractures in the third dimension, and diffusion and sorption into fracture-filling gouge, small altered rock matrix blocks within the fracture zone, and the unaltered semi-infinite rock matrix on both sides of the fracture zone (Tsan… more
Date: November 7, 2007
Creator: Doughty, Christine; Tsang, Chin-Fu; Doughty, Christine & Uchida, Masahiro
Partner: UNT Libraries Government Documents Department
open access

Exact solution of the envelope equations for a matchedquadrupole-focused beam in the zero space-charge limit

Description: The Kapchinskij-Vladimirskij equations are widely used to study the evolution of the beam envelopes in a periodic system of quadrupole focusing cells. In this paper, we analyze the case of a matched beam. Our model is analogous to that used by Courant and Snyder [E.D. Courant and H.S. Snyder, Ann. Phys. 3, 1 (1958)] in obtaining a first-order approximate solution for a synchrotron. Here, we treat a linear machine and obtain an exact solution. The model uses a full occupancy, piecewise-constant … more
Date: November 7, 2008
Creator: Anderson, Oscar A. & LoDestro, L. L.
Partner: UNT Libraries Government Documents Department
open access

Confidence Level and Sensitivity Limits in High Contrast Imaging

Description: In long adaptive optics corrected exposures, exoplanet detections are currently limited by speckle noise originating from the telescope and instrument optics, and it is expected that such noise will also limit future high-contrast imaging instruments for both ground and space-based telescopes. Previous theoretical analysis have shown that the time intensity variations of a single speckle follows a modified Rician. It is first demonstrated here that for a circular pupil this temporal intensity d… more
Date: November 7, 2007
Creator: Marois, C
Partner: UNT Libraries Government Documents Department
open access

Intrasplicing coordinates alternative first exons with alternative splicing in the protein 4.1R gene

Description: In the protein 4.1R gene, alternative first exons splice differentially to alternative 3' splice sites far downstream in exon 2'/2 (E2'/2). We describe a novel intrasplicing mechanism by which exon 1A (E1A) splices exclusively to the distal E2'/2 acceptor via two nested splicing reactions regulated by novel properties of exon 1B (E1B). E1B behaves as an exon in the first step, using its consensus 5' donor to splice to the proximal E2'/2 acceptor. A long region of downstream intron is excised, j… more
Date: November 7, 2008
Creator: Conboy, John G.; Parra, Marilyn K.; Tan, Jeff S.; Mohandas, Narla & Conboy, John G.
Partner: UNT Libraries Government Documents Department
open access

DEVELOPING AND QUANTIFYING PARAMETERS FOR CLOSURE WELDING OVERPACKS CONTAINING RESEARCH REACTOR SPENT NUCLEAR FUEL AT HANFORD

Description: Fluor engineers developed a Gas Tungsten Arc Welding (GTAW) technique and parameters, demonstrated requisite weld quality and successfully closure-welded packaged spent nuclear fuel (SNF) overpacks at the Hanford Site. This paper reviews weld development and qualification activities associated with the overpack closure-welding and provides a summary of the production campaign. The primary requirement of the closure weld is to provide leaktight confinement of the packaged material against releas… more
Date: November 7, 2007
Creator: GR, CANNELL
Partner: UNT Libraries Government Documents Department
open access

Optical design of the TMX Thomson Scattering Diagnostic

Description: The Thomson Scattering Diagnostic on TMX was built to measure the electron temperature in the plug. The design was based on the 2XII system built by Tom Simonen. Substantial improvements were realized over the original design, these include: (1) improved sensitivity, (2) simultaneous multiple position sampling, (3) multiple pulse capability, (4) achromatic imaging, (5) vacuum alignment capability, (6) high reliability, and (7) built in calibration and performance monitoring.
Date: November 7, 1979
Creator: Frank, A.M.
Partner: UNT Libraries Government Documents Department
open access

Importance of level structure in nuclear reaction cross-section calculations. Revision 1

Description: It is shown that level-density expressions cannot adequately represent or substitute for level structure information when making calculations of the Hauser-Feshbach type for cross sections or isomer-ratios for nuclei in the first few MeV above their ground state. It is stated that such discrete level information should include both experimentally confirmed and theoretically predicted levels. The utility of discrete level information to optimize level density calculations, to compute isomer rati… more
Date: November 7, 1985
Creator: Gardner, M. A. & Gardner, D. G.
Partner: UNT Libraries Government Documents Department
open access

Start-up neutral-beam power supply system for MFTF

Description: This paper describes some of the design features and considerations of the MFTF start-up neutral-beam power supplies. In particular, we emphasize features of the system that will ensure MFTF compatibility and achieve the required reliability/availability for the MFTF to be successful.
Date: November 7, 1979
Creator: Mooney, L. J.
Partner: UNT Libraries Government Documents Department
open access

Progress on Lawrence Livermore Laboratory's superconducting High-Field Test Facility

Description: A split pair of multifilamentary Nb/sub 3/Sn conductor coils, inside a set of Nb-Ti background coils, is being built at Lawrence Livermore Laboratory (LLL) for use in the High-Field Test Facility (HFTF). The inside diameter of the Nb/sub 3/Sn winding is 40 cm, the peak field is 12 T, and the nominal conductor current is 5 kA. The coils are being built as part of the LLL high-field superconducting development program in which characterization of short samples is followed by demonstration in coil… more
Date: November 7, 1979
Creator: Cornish, D. N.; Harrison, H. L.; Jewell, A. M.; Leber, R. L.; Rosdahl, A. R.; Scanlan, R. M. et al.
Partner: UNT Libraries Government Documents Department
open access

Effects of relativity of RTEX in collisions of U sup q+ with light targets

Description: We have calculated the resonant transfer and excitation cross sections in collisions of U{sup q+} (q = 82, 89, 90) ion with H{sub 2}, He and C in impulse approximation using the multi-configuration Dirac-Fock method. The calculations were carried out in intermediate coupling with configuration interaction. The quantum electrodynamic and finite nuclear size corrections were included in the calculations of transition energies. The Auger rates were calculated including the contributions from Coulo… more
Date: November 7, 1990
Creator: Chen, Mau Hsiung.
Partner: UNT Libraries Government Documents Department
open access

High power CW performance from a Ti:Sapphire laser and a single-pass amplifier

Description: Using two argon-ion lasers to pump a CW Ti:Sapphire laser we have demonstrated consistent high power (19 watts) operation with a low order spatial mode. Thermal lensing effects were controlled by enclosing the laser in a vacuum and cooling the rod with liquid nitrogen. Using this laser we also demonstrated a CW Ti:Sapphire amplifier with an efficiency of 20%. 5 refs., 5 figs.
Date: November 7, 1990
Creator: Erbert, G. V.; Bass, I. L.; Hackel, R. P.; Jenkins, S.; Kanz, K. V. & Paisner, J. A.
Partner: UNT Libraries Government Documents Department
open access

Design of laser-generated shockwave experiments. An approach using analytic models

Description: Two of the target-physics phenomena which must be understood before a clean experiment can be confidently performed are preheating due to suprathermal electrons and shock decay due to a shock-rarefaction interaction. Simple analytic models are described for these two processes and the predictions of these models are compared with those of the LASNEX fluid physics code. We have approached this work not with the view of surpassing or even approaching the reliability of the code calculations, but … more
Date: November 7, 1980
Creator: Lee, Y. T. & Trainor, R. J.
Partner: UNT Libraries Government Documents Department
open access

Same-Sign Dilepton Production by Neutrinos

Description: There has been considerable experimental work on same-sign dilepton production in neutrino interactions over the past 10 years. However, the situation is still unclear. Most experiments do have evidence for an excess of candidates but there is a lack of independent statistically significant results. Present experiments at the Tevatron may provide important new information. However the recent revision of older results and the lower rates from recent experiments indicate that real progress will b… more
Date: November 7, 1985
Creator: Murtagh, Michael J.
Partner: UNT Libraries Government Documents Department
Back to Top of Screen