Search Results

Advanced search parameters have been applied.
open access

Accent and Grouping Structures in the String Quartets of Béla Bartók

Description: The music of Béla Bartók is defined in part by its unique blend of rhythmic vitality and inventiveness, and his string quartets offer a glimpse into a consistency of technique evident throughout his compositional career. Bartók's rhythmic environments are primarily metrical, but many of his rhythmic configurations are placed in such a way as to potentially override established meter. It is necessary, therefore, to institute an analytical means by which the delineation and comparison of rhyt… more
Date: May 2001
Creator: Bocanegra, Cheryl D.
Partner: UNT Libraries
open access

Use of Optically Stimulated Luminescence Imaging Plates and Reader for Arms Control Applications

Description: Optically Stimulated Luminescence (OSL) technology has been pioneered at the Pacific Northwest National Laboratory (PNNL) for applications in personnel radiation dosimetry and commercially has become highly successful in replacing older technologies such as Thermoluminescence Dosimeters (TLDs) and film. OSL phosphors are used to measure radiation exposure by illuminating them with light after ionizing radiation exposure and measuring the amount of light emitted by the OSL phosphor. By using a t… more
Date: July 5, 2001
Creator: Miller, Steven D.; Tomeraasen, Paul L.; Burghard, Brion J. & Traub, Richard J.
Partner: UNT Libraries Government Documents Department
open access

Kinetics of the [beta]-[delta]phase transition in PBX9501.

Description: The initial step in the thermal decomposition of HMX is the solid state phase transition from the centrosymmetric beta form to the noncentrosymmetric delta form. The symmetry change makes the phase transition amenable to the application of second harmonic generation (SHG) as a probe of transition kinetics. We have used SHG to study the temperature dependence of the kinetics for unconfined PBX9501 and HMX. Spatially resolved SHG measurements have shown a nucleation and growth mechanism for the s… more
Date: January 1, 2001
Creator: Smilowitz, L. B. (Laura B.); Henson, B. F. (Bryan F.); Asay, B. W. (Blaine W.); Dickson, P. M. (Peter M.) & Robinson, J. M. (Jeanne M.)
Partner: UNT Libraries Government Documents Department
open access

Nature's statistical symmetries and asymmetries, a characterization by wavelets and an illustration with clouds

Description: Wavelets are the mathematical equivalent of a microscope, a means of looking at more or less detail in data. By applying wavelet transforms to remote sensing data (satellite images, atmospheric profiles, etc.), we can discover symmetries in Nature's ways of changing in time and displaying a highly variable environment at any given time. These symmetries are not exact but statistical. The most intriguing one is 'scale-invariance' which describes how spatial statistics collected over a wide range… more
Date: January 1, 2001
Creator: Davis, A. B. (Anthony B.)
Partner: UNT Libraries Government Documents Department
open access

Measurement of the current and symmetry of the impact liner on the NTLX experiments

Description: A series of four liner implosion experiments, denoted the Near Tern Liner Experiments (NTLX) was recently conducted on the Shiva Star capacitor bank at the Air Force Research Laboratory (AFRL). Measurement of the driving currents in these experiments is required for postshot analysis of the liner implosion and experiments conducted in the target cylinder. A Faraday rotation measurement was fielded on Shiva Star to measure the current and compare with the current measured by a Rogowski coil tech… more
Date: January 1, 2001
Creator: Stokes, J. L. (John L.); Tabaka, L. J. (Leonard J.); Parker, J. V. (Jerald V.); Anderson, D. N.; Corrow, R.; Pritchett, R. et al.
Partner: UNT Libraries Government Documents Department
open access

Models of Scherk-Schwarz Symmetry Breaking in 5D: Classification and Calculability

Description: The form of the most general orbifold breaking of gauge, global and supersymmetries with a single extra dimension is given. In certain theories the Higgs boson mass is ultraviolet finite due to an unbroken local supersymmetry, which is explicitly exhibited. We construct: a 1 parameter SU(3) \times SU(2) \times U(1) theory with 1 bulk Higgs hypermultiplet, a 2 parameter SU(3) \times SU(2) \times U(1) theory with 2 bulk Higgs hypermultiplets, and a 2 parameter SU(5) \to SU(3) \times SU(2) \times … more
Date: July 1, 2001
Creator: Barbieri, Riccardo; Hall, Lawrence J. & Nomura, Yasunori
Partner: UNT Libraries Government Documents Department
open access

R-matrix for a geodesic flow associated with a new integrable peakon equation

Description: We use the r-matrix formulation to show the integrability of geodesic flow on an N-dimensional space with coordinates q k, with k = 1, ..., N, equipped with the co-metric g i j = e-141--431(2 - e-Iq1-q3l). This flow is generated by a symmetry of the integrable partial differential equation (pde) mt + um, + 3mux = 0, m = u - a2uZx( ai s a constant), which was recently proven to be completely integrable and possess peakon solutions by Degasperis, Holm and Hone. The isospectral eigenvalue problem … more
Date: January 1, 2001
Creator: Holm, Darryl D. & Qiao, Z. (Zhijun)
Partner: UNT Libraries Government Documents Department
open access

Radiographic results from the NTLX series of hydrodynamic experiments

Description: The NTLX series of experiments are focused on measuring the shock induced hydrodynamic flow of a Sn-PMMA target. For these experiments multi-frame flash X-ray radiography is used to measure the position of the Sn-PMMA target interface and the location of shock in the PMMA as a function of time. Four radiographs are acquired at 700 ns intervals having a line-of-sight following the target's axis of symmetry. Because the Xray spectrum from the sources has an end-point energy of {approx}300 keV wit… more
Date: January 1, 2001
Creator: Olson, Russell T.; Oro, David M.; Anderson, Brodie G.; Studebaker, Jan K.; Alvey, Ken; Peterson, Ken et al.
Partner: UNT Libraries Government Documents Department
open access

The Quasi-Toroidal Stellarator: An Innovative Confinement Experiment

Description: To develop a new class of stellarators that exhibit improved confinement compared to conventional stellarators. This approach generally makes use of a designed symmetry of the magnetic field strength along a particular coordinate axis in the toroidal geometry of the stellarator, and is referred to as quasi-symmetry.
Date: April 1, 2001
Creator: Knowlton, S. F.
Partner: UNT Libraries Government Documents Department
open access

In/Si(111): Self-assembled one and two-dimensional electrongases

Description: We present angle-resolved photoemission measurements forultrathin In films on Si(111). Depending on the coverage, this systemself-organizes into a metallic monolayer with either 4x1 or sqrt7 x sqrt3symmetry relative to the substrate. Electronically, they behave likeideal one- and two-dimensional electron gases (1DEG and 2DEG),respectively. The 4x1 system has atomic chains of In whose energy bandsdisperse only parallel to the chains, while for the sqrt7 x sqrt3 system,the dominant reciprocal spa… more
Date: January 22, 2001
Creator: Rotenberg, Eli; Yeom, H. W.; Takeda, S.; Matsuda, I.; Horikoshi, K.; Schaefer, J. et al.
Partner: UNT Libraries Government Documents Department
open access

Issues of an Eulerian/ALE algorithm based on a compatible, staggered-grid, Lagrangian step

Description: In this paper a number of distinct issues that are of concern in the construction of an Eulerian or ALE algorithm by means of a Lagrangian step and separate remap are explored. First, the common advection test problems usually cited in the literature pertaining to limiter construction are not wholly suitable to accessing the advection quality of an Eulerian scheme. A more appropriate set of test problems are derived to satisfy this need. Next, the basic philosophy of an ALE algorithm is that it… more
Date: January 1, 2001
Creator: Caramana, E. J. (Edward J.)
Partner: UNT Libraries Government Documents Department
open access

Molecular Organization in the Native State of Wood Cell Walls: Studies of Nanoscale Structure and its Development

Description: With respect to cell wall biogenesis we have developed a theory concerning the formation of lignin in which the regulation of structure is attributed to the hemicelluloses; they are viewed as templates for the assembly of lignin. The key supporting evidence is derived from the symmetry of annual rings in trees free of reaction wood. This symmetry is interpreted to point to genetic encoding as the dominant factor in the pattern of interunit linkages in lignin. More recently, we have explored fur… more
Date: February 1, 2001
Creator: Atalla, R. H.
Partner: UNT Libraries Government Documents Department
open access

Gauge unification in higher dimensions

Description: A complete 5-dimensional SU(5) unified theory is constructed which, on compactification on the orbifold with two different Z{sub 2}'s (Z{sub 2} and Z{sub 2}{prime}), yields the minimal supersymmetric standard model. The orbifold accomplishes SU(5) gauge symmetry breaking, doublet-triplet splitting, and a vanishing of proton decay from operators of dimension 5. Until 4d supersymmetry is broken, all proton decay from dimension 4 and dimension 5 operators is forced to vanish by an exact U(1){sub R… more
Date: January 14, 2001
Creator: Hall, Lawrence & Nomura, Yasunori
Partner: UNT Libraries Government Documents Department
open access

A control-theoretic formulation of the bunch train cavity interaction.

Description: The bunch train cavity interaction is an accelerator physics problem, for which a system-theoretic model is lacking. Modal analysis has been used to characterize the system dynamics, exploiting the system's symmetry. Correspondingly, control design has been done using classical frequency-domain-based control. Several shortcomings of these methods are highlighted, all of which are remedied by a new time-domain, system-theoretic model presented herein. The new formulation is a periodic, discrete-… more
Date: March 6, 2001
Creator: Schwartz, C.; Haddad, H. & Nassiri, A.
Partner: UNT Libraries Government Documents Department
open access

Exactly averaged stochastic equations for flow and transport in random media

Description: It is well known that exact averaging of the equations of flow and transport in random porous media are at present realized only for a small number of special, occasionally exotic, fields. On the other hand, the properties of approximate averaging methods are not yet fully understood. For example, the convergence behavior and the accuracy of truncated perturbation series are not well known. Furthermore, the calculation of the high-order perturbations is very complicated. These problems for a lo… more
Date: November 30, 2001
Creator: Shvidler, Mark & Karasaki, Kenzi
Partner: UNT Libraries Government Documents Department
open access

The Role of Axisymmetric Reconnection Events in JET Discharges with Extreme Shear Reversal

Description: Injection of Lower Hybrid Heating and Current Drive into the current ramp-up phase of Joint European Torus (JET) discharges can produce extremely reversed q-profiles characterized by a core region of very small or zero current density (within Motional Stark Effect diagnostic measurement errors) and q(subscript min) > 1. T(subscript e)-profiles show sawtooth-like collapses and the presence of an internal transport barrier. Accurate equilibrium reconstructions of these discharges are obtained … more
Date: December 3, 2001
Creator: Stratton, B. C.; Breslau, J. A.; Budny, R. V.; Jardin, S. C.; Park, W.; Strauss, H. R. et al.
Partner: UNT Libraries Government Documents Department
open access

Strange Goings on in Quark Matter.

Description: We review recent work on how the superfluid state of three flavor quark matter is affected by non-zero quark masses and chemical potentials. The study of hadronic matter at high baryon density has recently attracted a lot of interest. At zero baryon density chiral symmetry is broken by a quark-anti-quark condensate. At high density condensation in the quark-anti-quark channel is suppressed. Instead, attractive interactions in the color anti-symmetric quark-quark channel favor the formation of d… more
Date: June 5, 2001
Creator: Schafer, T.
Partner: UNT Libraries Government Documents Department
open access

Almost Optimal Interior Penalty Discontinuous Approximations of Symmetric Elliptic Problems on Non-Matching Grids

Description: We consider an interior penalty discontinuous approximation for symmetric elliptic problems of second order on non-matching grids in this paper. The main result is an almost optimal error estimate for the interior penalty approximation of the original problem based on the partition of the domain into a finite number of subdomains. Further, an error analysis for the finite element approximation of the penalty formulation is given. Finally, numerical experiments on a series of model second order … more
Date: August 8, 2001
Creator: Lazarov, R D; Pasciak, J E; Schoberl, J & Vassilevski, P S
Partner: UNT Libraries Government Documents Department
open access

Detecting Translation Errors in CAD Surfaces and Preparing Geometries for Mesh Generation

Description: The authors have developed tools for the efficient preparation of CAD geometries for mesh generation. Geometries are read from IGES files and then maintained in a boundary-representation consisting of a patchwork of trimmed and untrimmed surfaces. Gross errors in the geometry can be identified and removed automatically while a user interface is provided for manipulating the geometry (such as correcting invalid trimming curves or removing unwanted details). Modifying the geometry by adding or de… more
Date: August 27, 2001
Creator: Petersson, N Anders & Chand, K K
Partner: UNT Libraries Government Documents Department
open access

EIGER: Electromagnetic Interactions GEneRalized

Description: The EIGER (Electromagnetic Interactions Generalized) modeling suite is a joint development activity by the Lawrence Livermore National Lab, Sandia National Labs, the University of Houston, and the Navy (Space and Naval Warfare Systems Center-San Diego). The effort endeavors to bring the next generation of hybrid, higher-order, full-wave analysis methods into a single integrated framework. The tools are based upon frequency-domain solutions of Maxwell's equations to model scattering and radiatio… more
Date: June 13, 2001
Creator: Champagne, N J; Sharpe, R M & Rockway, J W
Partner: UNT Libraries Government Documents Department
open access

Infrared Heating of Hydrogen Layers in Hohlraums

Description: The authors report results of modeling and experiments on infrared heated deuterium-hydride (HD) layers in hohlraums. A 2 mm diameter, 40 {micro}m thick shell with 100-400 {micro}m thick HD ice inside a NIF scale-1 gold hohlraum with 1-3 {micro}m rms surface roughness is heated by pumping the HD vibrational bands. Models indicate control of the low-mode layer shape by adjusting the infrared distribution along the hohlraum walls. They have experimentally demonstrated control of the layer symmetr… more
Date: August 15, 2001
Creator: Kozioziemski, B J; McEachern, R L; London, R A & Bitter, D N
Partner: UNT Libraries Government Documents Department
open access

GUT breaking on the brane?

Description: We present a five-dimensional supersymmetric SU(5) theory in which the gauge symmetry is broken maximally (i.e. at the 5D Planck scale M{sub *}) on the same 4D brane where chiral matter is localized. Masses of the lightest Kaluza-Klein modes for the colored Higgs and X and Y gauge fields are determined by the compactification scale of the fifth dimension, M{sub C} {approx} 10{sup 15} GeV, rather than by M{sub *}. These fields' wave functions are repelled from the GUT-breaking brane, so that pro… more
Date: April 4, 2001
Creator: Smith, David; Nomura, Yasunori & Weiner, Neal
Partner: UNT Libraries Government Documents Department
open access

Studies in Quantum Field Theory. Final Report, July 21, 1992 - July 31, 1999

Description: Mechanisms have been investigated for chiral symmetry breaking in QED and non-abelian gauge theories using the Schwinger proper-time formalism. Multi-soliton and plane-wave solutions have been generated in affine Toda field theories. New predictions for neutrino mass generation via superfluid-type condensates in the Electroweak theory have been made. Solutions for the linear inhomogeneous bioheat equation were studied in cylindrical geometries.
Date: March 31, 2001
Creator: Caldi, Daniel G.
Partner: UNT Libraries Government Documents Department
open access

Ballooning Stability of the Compact Quasiaxially Symmetric Stellarator

Description: The magnetohydrodynamic (MHD) ballooning stability of a compact, quasiaxially symmetric stellarator (QAS), expected to achieve good stability and particle confinement is examined with a method that can lead to estimates of global stability. Making use of fully 3D, ideal-MHD stability codes, the QAS beta is predicted to be limited above 4% by ballooning and high-n kink modes. Here MHD stability is analyzed through the calculation and examination of the ballooning mode eigenvalue isosurfaces in t… more
Date: September 19, 2001
Creator: Redi, M. H.; Canik, J.; Dewar, R. L.; Johnson, J. L.; Klasky, S.; Cooper, W. A. et al.
Partner: UNT Libraries Government Documents Department
Back to Top of Screen