Partner
UNT Libraries Government Documents Department
181
UNT Libraries
56
UNT Libraries Special Collections
32
Oklahoma Historical Society
31
UNT Music Library
25
Burleson Public Library
12
National Museum of the Pacific War/Admiral Nimitz Foundation
12
Sterling Municipal Library
9
UNT College of Visual Arts + Design
8
Brownwood Public Library
7
61 More
Collection
Texas Digital Newspaper Program
197
Office of Scientific & Technical Information Technical Reports
91
Tocker Foundation Grant
75
Congressional Research Service Reports
74
The Greensheet
38
Oklahoma Digital Newspaper Program
38
Ladd & Katherine Hancher Library Foundation
25
College of Music Recordings
23
UNT Scholarly Works
17
Burleson Area Newspaper Collection
12
98 More
Degree Department
Degree Discipline
Degree Level
Country
Year
Month
Day
A Multigrid-in-Time Algorithm for Solving Evolution Equations in Parallel
None
Date:
December 5, 2012
Creator:
Friedhoff, S; Falgout, R D; Kolev, T V; MacLachlan, S & Schroder, J B
Object Type:
Article
System:
The UNT Digital Library
Re-architecting TEIMS Web-based Legacy Applications Using the Model View Controller Paradigm
None
Date:
September 5, 2012
Creator:
Barbosa, E & Laguna, G W
Object Type:
Article
System:
The UNT Digital Library
Release of aged contaminants from weathered sediments: Effects of sorbate speciation on scaling of reactive transport
Hanford sediments impacted by hyperalkaline high level radioactive waste have undergone incongruent silicate mineral weathering concurrent with contaminant uptake. In this project, we studied the impact of background pore water (BPW) on strontium, cesium and iodine desorption and transport in Hanford sediments that were experimentally weathered by contact with simulated hyperalkaline tank waste leachate (STWL) solutions. Using those lab-weathered Hanford sediments (HS) and model precipitates formed during nucleation from homogeneous STWL solutions (HN), we (i) provided thorough characterization of reaction products over a matrix of field-relevant gradients in contaminant concentration, partial pressure of carbon dioxide, and reaction time; (ii) improved molecular-scale understanding of how sorbate speciation controls contaminant desorption from weathered sediments upon removal of caustic sources; and (iii) developed a mechanistic, predictive model of meso- to field-scale contaminant reactive transport under these conditions. In this final report, we provide detailed descriptions of our results from this three-year study, completed in 2012 following a one-year no cost extension.
Date:
November 5, 2012
Creator:
Chorover, Jon; Perdrial, Nico; Mueller, Karl; Strepka, Caleb; OÃÂâÃÂÃÂÃÂÃÂDay, Peggy; Rivera, Nelson et al.
Object Type:
Report
System:
The UNT Digital Library
Ab-initio calculation of optical properties of wurtzitic In_x Ga_1x N and In_x Al_1x N alloys including excitonic effects
None
Date:
September 5, 2012
Creator:
de Carvalho, L C; Schleife, A; Furthmueller, J & Bechstedt, F
Object Type:
Article
System:
The UNT Digital Library
Search for a Low-Mass Higgs Boson (A0) at BaBar
The BABAR Collaboration has performed three searches for a light Higgs boson, A{sup 0}, in radiative Upsilon ({Upsilon}) decays: {Upsilon}(3S) {yields} {gamma}A{sup 0}, A{sup 0} {yields} {tau}{sup +}{tau}{sup -}; {Upsilon}(nS) {yields} {gamma}A{sup 0}, A{sup 0} {yields} {mu}{sup +}{mu}{sup -} (n = 2,3); and {Upsilon}(3S) {yields} {gamma}A{sup 0}, A{sup 0} {yields} invisible. Such a Higgs boson (A{sup 0}) appears in the Next-to-Minimal Supersymmetric extensions of the Standard Model, where a light CP-odd Higgs boson couples strongly to b-quarks. The searches are based on data samples that consist of 122 x 10{sup 6} {Upsilon}(3S) and 99 x 10{sup 6} {Upsilon}(2S) decays, collected by the BABAR detector at the SLAC National Accelerator Laboratory. The searches reveal no evidence for an A{sup 0}, and product of branching fractions upper limits, at 90% C.L., of (1.5-16) x 10{sup -5}, (0.44-44) x 10{sup -6}, and (0.7-31) x 10{sup -6} were obtained for these searches, respectively. Also, we set the upper limits {Beta}({eta}{sub b} {yields} {tau}{sup +}{tau}{sup -}) < 8% and {Beta}({eta}{sub b} {yields} {mu}{sup +}{mu}{sup -}) < 0.9%.
Date:
April 5, 2012
Creator:
Mokhtar, Arafat Gabareen
Object Type:
Article
System:
The UNT Digital Library
Electron Transport Studies of Annular Exploders
None
Date:
November 5, 2012
Creator:
Strozzi, D. J.; Tabak, M.; Shay, H. D. & Larson, D. J.
Object Type:
Article
System:
The UNT Digital Library
High Cost/High Risk Components to Chalcogenide Molded Lens Model: Molding Preforms and Mold Technology
This brief report contains a critique of two key components of FiveFocal's cost model for glass compression molding of chalcogenide lenses for infrared applications. Molding preforms and mold technology have the greatest influence on the ultimate cost of the product and help determine the volumes needed to select glass molding over conventional single-point diamond turning or grinding and polishing. This brief report highlights key areas of both technologies with recommendations for further study.
Date:
October 5, 2012
Creator:
Bernacki, Bruce E.
Object Type:
Report
System:
The UNT Digital Library
Towards Recovering Provenance with Experiment Explorer
None
Date:
October 5, 2012
Creator:
Davis, D. B.; Asuncion, H. U.; Abdulla, G. M. & Carr, C. W.
Object Type:
Article
System:
The UNT Digital Library
Compressing Phasor Measurement Data
None
Date:
December 5, 2012
Creator:
Top, P. & Breneman, J.
Object Type:
Article
System:
The UNT Digital Library
Observation of Laser Induced Magnetization Dynamics in Co/Pd Multilayers with Coherent X-ray Scattering
We report on time-resolved coherent x-ray scattering experiments of laser induced magnetization dynamics in Co/Pd multilayers with a high repetition rate optical pump x-ray probe setup. Starting from a multi-domain ground state, the magnetization is uniformly reduced after excitation by an intense 50 fs laser pulse. Using the normalized time correlation, we study the magnetization recovery on a picosecond timescale. The dynamic scattering intensity is separated into an elastic portion at length scales above 65 nm which retains memory of the initial domain magnetization, and a fluctuating portion at smaller length scales corresponding to domain boundary motion during recovery.
Date:
April 5, 2012
Creator:
Wu, Benny
Object Type:
Article
System:
The UNT Digital Library
ENERGY PARTITIONING, ENERGY COUPLING (EPEC) EXPERIMENTS AT THE NATIONAL IGNITION FACILITY
The energy-partitioning, energy-coupling (EPEC) experiments at the National Ignition Facility (NIF) will simultaneously measure the coupling of energy into both ground shock and air-blast overpressure from a laser-driven target. The source target for the experiment is positioned at a known height above the ground-surface simulant and is heated by four beams from NIF. The resulting target energy density and specific energy are equal to those of a low-yield nuclear device. The ground-shock stress waves and atmospheric overpressure waveforms that result in our test system are hydrodynamically scaled analogs of seismic and air-blast phenomena caused by a nuclear weapon. In what follows, we discuss the motivation for our investigation and briefly describe NIF. Then, we introduce the EPEC experiments, including diagnostics, in more detail.
Date:
January 5, 2012
Creator:
Fournier, K B; Brown, C G; May, M J; Dunlop, W H; Compton, S M; Kane, J O et al.
Object Type:
Report
System:
The UNT Digital Library
Lead Research and Development Activity for DOE's High Temperature, Low Relative Humidity Membrane Program (Topic 2)
The Department of Energy’s High Temperature, Low Relative Humidity Membrane Program was begun in 2006 with the Florida Solar Energy Center (FSEC) as the lead organization. During the first three years of the program, FSEC was tasked with developing non-Nafion® proton exchange membranes with improved conductivity for fuel cells. Additionally, FSEC was responsible for developing protocols for the measurement of in-plane conductivity, providing conductivity measurements for the other funded teams, developing a method for through-plane conductivity and organizing and holding semiannual meetings of the High Temperature Membrane Working Group (HTMWG). The FSEC membrane research focused on the development of supported poly[perfluorosulfonic acid] (PFSA) – Teflon membranes and a hydrocarbon membrane, sulfonated poly(ether ether ketone). The fourth generation of the PFSA membrane (designated FSEC-4) came close to, but did not meet, the Go/No-Go milestone of 0.1 S/cm at 50% relative humidity at 120 °C. In-plane conductivity of membranes provided by the funded teams was measured and reported to the teams and DOE. Late in the third year of the program, DOE used this data and other factors to decide upon the teams to continue in the program. The teams that continued provided promising membranes to FSEC for development of membrane electrode …
Date:
September 5, 2012
Creator:
Fenton, James; Slattery, Darlene & Mohajeri, Nahid
Object Type:
Report
System:
The UNT Digital Library
The Injection System of the INFN-SuperB Factory Project: Preliminary Design
The ultra high luminosity B-factory (SuperB) project of INFN requires a high performance and reliable injection system, providing electrons at 4 GeV and positrons at 7 GeV, to fulfil the very tight requirements of the collider. Due to the short beam lifetime, continuous injection of electron and positron bunches in both LER and HER rings is necessary to maintain an high average luminosity. Polarized electrons are required for experiments and must be delivered by the injection system, due to the beam lifetime shorter than the ring polarization build-up: they will be produced by means of a SLAC-SLC polarized gun. The emittance and the energy spread of the e{sup -}/e{sup +} beams are reduced in a 1 GeV Damping Ring (DR) before injection in the main rings. Two schemes for positron production are under study, one with e{sup -}/e{sup +} conversion at low energy (< 1 Gev) and one with conversion at 6 GeV and a recirculation line to bring the positrons back to the DR. Acceleration through the Linac is provided by a 2856 MHz RF system made of travelling wave (TW), room temperature accelerating structures.
Date:
July 5, 2012
Creator:
Boni, Roberto; Guiducci, Susanna; Preger, Miro; Raimondi, Pantaleo; Chance, Antoine; Dadoun, Olivier et al.
Object Type:
Article
System:
The UNT Digital Library
Gauge Properties Of The Guiding Center Variational Symplectic Integrator
Recently, variational symplectic algorithms have been developed for the long-time simulation of charged particles in magnetic fields1-3. As a direct consequence of their derivation from a discrete variational principle, these algorithms have very good long-time energy conservation, as well as exactly preserving discrete momenta. We present stability results for these algorithms, focusing on understanding how explicit variational integrators can be designed for this type of system. It is found that for explicit algorithms an instability arises because the discrete symplectic structure does not become the continuous structure in the t → 0 limit. We examine how a generalized gauge transformation can be used to put the Lagrangian in the "antisymmetric discretization gauge," in which the discrete symplectic structure has the correct form, thus eliminating the numerical instability. Finally, it is noted that the variational guiding center algorithms are not electromagnetically gauge invariant. By designing a model discrete Lagrangian, we show that the algorithms are approximately gauge invariant as long as A and #30; are relatively smooth. A gauge invariant discrete Lagrangian is very important in a variational particle-in-cell algorithm where it ensures current continuity and preservation of Gauss's law4.
Date:
March 5, 2012
Creator:
J. Squire, H. Qin and W. Tang
Object Type:
Report
System:
The UNT Digital Library
Advances in X-Band TW Accelerator Structures Operating in the 100 MV/M Regime
A CERN-SLAC-KEK collaboration on high gradient X-band accelerator structure development for CLIC has been ongoing for three years. The major outcome has been the demonstration of stable 100 MV/m gradient operation of a number of CLIC prototype structures. These structures were fabricated using the technology developed from 1994 to 2004 for the GLC/NLC linear collider initiative. One of the goals has been to refine the essential parameters and fabrication procedures needed to realize such a high gradient routinely. Another goal has been to develop structures with stronger dipole mode damping than those for GLC/NLC. The latter requires that the surface temperature rise during the pulse be higher, which may increase the breakdown rate. One structure with heavy damping has been RF processed and another is nearly finished. The breakdown rates of these structures were found to be higher by two orders of magnitude compared to those with equivalent acceleration mode parameters but without the damping features. This paper presents these results together with some of the earlier results from non-damped structures.
Date:
July 5, 2012
Creator:
Higo, Toshiyasu; Higashi, Yasuo; Matsumoto, Shuji; Yokoyama, Kazue; Adolphsen, Chris; Dolgashev, Valery et al.
Object Type:
Article
System:
The UNT Digital Library
Discovery of Very High Energy Gamma Rays from PKS 1424+240 and Multiwavelength Constraints on its Redshift
We report the first detection of very-high-energy (VHE) gamma-ray emission above 140GeV from PKS 1424+240, a BL Lac object with an unknown redshift. The photon spectrum above 140GeV measured by VERITAS is well described by a power law with a photon index of 3.8 {+-}0.5{sub stat} {+-} 0.3{sub syst} and a flux normalization at 200 GeV of (5.1 {+-} 0.9{sub stat} {+-} 0.5{sub syst}) x 10{sup -11} TeV{sup -1} cm{sup -2} s{sup -1}, where stat and syst denote the statistical and systematical uncertainty, respectively. The VHE flux is steady over the observation period between MJD 54881 and 55003 (2009 February 19 to June 21). Flux variability is also not observed in contemporaneous high energy observations with the Fermi Large Area Telescope (LAT). Contemporaneous X-ray and optical data were also obtained from the Swift XRT and MDM observatory, respectively. The broadband spectral energy distribution (SED) is well described by a one-zone synchrotron self-Compton (SSC) model favoring a redshift of less than 0.1. Using the photon index measured with Fermi in combination with recent extragalactic background light (EBL) absorption models it can be concluded from the VERITAS data that the redshift of PKS 1424+240 is less than 0.66.
Date:
April 5, 2012
Creator:
Acciari, V. A.; Aliu, E.; Arlen, T.; Aune, T.; Bautista, M.; Beilicke, M. et al.
Object Type:
Report
System:
The UNT Digital Library
Validation of Numerical Simulations of Explosion Fields
None
Date:
December 5, 2012
Creator:
Kuhl, A L
Object Type:
Report
System:
The UNT Digital Library
Identification and Characterization of Prokaryotic Regulatory Networks: Final Report
We have completed our characterization of both the transcriptional regulatory network and post-transcriptional regulatory motifs in Shewanella.
Date:
October 5, 2012
Creator:
Stormo, Gary D.
Object Type:
Report
System:
The UNT Digital Library
Analysis of Deformation Twinning in Tantalum Single Crystals Under Shock Loading Conditions
None
Date:
December 5, 2012
Creator:
Florando, J. N.; Barton, N. R.; El-Dasher, B.; McNaney, J. M. & Kumar, M.
Object Type:
Article
System:
The UNT Digital Library
Expert Unreviewed Safety Question Determinations (USQD)
None
Date:
April 5, 2012
Creator:
Mitchell, M A & Montgomery, P
Object Type:
Article
System:
The UNT Digital Library
Design & Fabrication of a High-Voltage Photovoltaic Cell
Silicon photovoltaic (PV) cells are alternative energy sources that are important in sustainable power generation. Currently, applications of PV cells are limited by the low output voltage and somewhat low efficiency of such devices. In light of this fact, this project investigates the possibility of fabricating high-voltage PV cells on float-zone silicon wafers having output voltages ranging from 50 V to 2000 V. Three designs with different geometries of diffusion layers were simulated and compared in terms of metal coverage, recombination, built-in potential, and conduction current density. One design was then chosen and optimized to be implemented in the final device design. The results of the simulation serve as a feasibility test for the design concept and provide supportive evidence of the effectiveness of silicon PV cells as high-voltage power supplies.
Date:
September 5, 2012
Creator:
Felder, Jennifer & /SLAC, /North Carolina State U.
Object Type:
Report
System:
The UNT Digital Library
Analysis on linac quadrupole misalignment in FACET commissioning 2012
In this note, the analysis on linac quadrupole misalignment is presented for the FACET linac section LI05-09 plus LI11-19. The effectiveness of the beam-based alignment technique is preliminarily confirmed by the measurement. Beam-based alignment technique was adopted at SLAC linac since SLC time. Here the beam-based alignment algorithms are further developed and applied in the FACET commissioning during 2012 run.
Date:
July 5, 2012
Creator:
Sun, Yipeng
Object Type:
Report
System:
The UNT Digital Library
Focused-ion-beam Assisted Growth, Patterning, and Narrowing the Size Sidtributions of ZnO Nanowires for Variable Optical Properties and Enhanced Non-mechanical Energy Conversion
None
Date:
November 5, 2012
Creator:
Wang, X. Y.; Xie, S. F.; Liu, J.; Kucheyev, S. O. & Wang, Y. M.
Object Type:
Article
System:
The UNT Digital Library
Characterization of fundamental catalytic properties of MoS2/WS2 nanotubes and nanoclusters for desulfurization catalysis - a surface temperature study
The prior project consisted of two main project lines. First, characterization of novel nanomaterials for hydrodesulfurization (HDS) applications. Second, studying more traditional model systems for HDS such as vapor-deposited silica-supported Mo and MoSx clusters. In the first subproject, we studied WS2 and MoS2 fullerene-like nanoparticles as well as WS2 nanotubes. Thiophene (C4H4S) was used as the probe molecule. Interestingly, metallic and sulfur-like adsorption sites could be identified on the silica-supported fullerene-particles system. Similar structures are seen for the traditional system (vapor-deposited clusters). Thus, this may be a kinetics fingerprint feature of modern HDS model systems. In addition, kinetics data allowed characterization of the different adsorption sites for thiophene on and inside WS2 nanotube bundles. The latter is a unique feature of nanotubes that has not been reported before for any inorganic nanotube system; however, examples are known for carbon nanotubes, including prior work of the PI. Although HDS has been studied for decades, utilizing nanotubes as nanosized HDS reactors has never been tried before, as far as we know. This is of interest from a fundamental perspective. Unfortunately, the HDS activity of the nanocatalysts at ultra-high vacuum (UHV) conditions was close to the detection limit of our techniques. Therefore, we …
Date:
July 5, 2012
Creator:
Burghaus, U.
Object Type:
Report
System:
The UNT Digital Library