Optical absorption in transparent conducting oxides: Mott transition or Mahan excitons? (open access)

Optical absorption in transparent conducting oxides: Mott transition or Mahan excitons?

None
Date: May 17, 2011
Creator: Schleife, A.; Rodl, C.; Fuchs, F.; Hannewald, K. & Bechstedt, F.
Object Type: Article
System: The UNT Digital Library
Science and Technology Review July/August 2011 (open access)

Science and Technology Review July/August 2011

None
Date: June 17, 2011
Creator: Nikolic, R. J.
Object Type: Report
System: The UNT Digital Library
NIF Capsule Performance Modeling (open access)

NIF Capsule Performance Modeling

None
Date: October 17, 2011
Creator: Weber, S.; Callahan, D.; Cerjan, C.; Edwards, J.; Haan, S.; Hicks, D. et al.
Object Type: Article
System: The UNT Digital Library
Exploration of the Versatility of Ring Opening Metathesis Polymerization: an Approach for Gaining Access to Low Density Polymeric Aerogels (open access)

Exploration of the Versatility of Ring Opening Metathesis Polymerization: an Approach for Gaining Access to Low Density Polymeric Aerogels

None
Date: November 17, 2011
Creator: Kim, S. H.; Worsley, M. A.; Valdez, C. A.; Shin, S. J.; Dawedeit, C.; Braun, T. et al.
Object Type: Article
System: The UNT Digital Library
Impact Plate Test Problem (open access)

Impact Plate Test Problem

None
Date: May 17, 2011
Creator: Weseloh, W & Najjar, F
Object Type: Report
System: The UNT Digital Library
Operation Tomodachi - DOE Response to the Japan Earthquake (open access)

Operation Tomodachi - DOE Response to the Japan Earthquake

None
Date: October 17, 2011
Creator: Wong, C. T.
Object Type: Article
System: The UNT Digital Library
Responses of deep ocean carbonate system to carbon reorganization and sea level changes (open access)

Responses of deep ocean carbonate system to carbon reorganization and sea level changes

None
Date: November 17, 2011
Creator: Yu, J.; Broekcer, W.; Jin, Z. & Rae, J.
Object Type: Article
System: The UNT Digital Library
Detailed chemical kinetic reaction mechanisms for soy and rapeseed biodiesel fuels (open access)

Detailed chemical kinetic reaction mechanisms for soy and rapeseed biodiesel fuels

None
Date: May 17, 2011
Creator: Westbrook, C K; Naik, C V; Herbinet, O; Pitz, W J; Mehl, M; Sarathy, S M et al.
Object Type: Article
System: The UNT Digital Library
Best Practices in Support of Implementing the revised DOE USQ Guide, DOE G 424.1-1B (open access)

Best Practices in Support of Implementing the revised DOE USQ Guide, DOE G 424.1-1B

None
Date: October 17, 2011
Creator: Mitchell, M A
Object Type: Article
System: The UNT Digital Library
Event-by-event evaluation of the prompt fission neutron spectrum from 239Pu(n, f) (open access)

Event-by-event evaluation of the prompt fission neutron spectrum from 239Pu(n, f)

None
Date: May 17, 2011
Creator: Vogt, R.; Randrup, J.; Brown, D. A.; Descalle, M. A. & Ormand, E.
Object Type: Article
System: The UNT Digital Library
Extending ATP to High Frequencies (open access)

Extending ATP to High Frequencies

None
Date: November 17, 2011
Creator: Scharlemann, E.
Object Type: Report
System: The UNT Digital Library
Workshop on Laser Plasma Interactions on the National Ignition Facility (open access)

Workshop on Laser Plasma Interactions on the National Ignition Facility

None
Date: May 17, 2011
Creator: Hinkel, D; Callahan, D & Glenzer, S H
Object Type: Article
System: The UNT Digital Library
Complete Genome Sequence of the Anaerobic, Halophilic Alkalithermophile Natranaerobius thermophilus JW/NM-WN-LF (open access)

Complete Genome Sequence of the Anaerobic, Halophilic Alkalithermophile Natranaerobius thermophilus JW/NM-WN-LF

None
Date: June 17, 2011
Creator: Han, J.; Nolan, M.; Kyrpides, N.; Pitluck, S.; Goodwin, L.; Zhao, B. et al.
Object Type: Article
System: The UNT Digital Library
The Boundary/Pedestal Integrated Science Application for FSP (open access)

The Boundary/Pedestal Integrated Science Application for FSP

None
Date: June 17, 2011
Creator: Rognlien, T D & Snyder, P B
Object Type: Report
System: The UNT Digital Library
Soft X-Ray and Vacuum Ultraviolet Based Spectroscopy of the Actinides (open access)

Soft X-Ray and Vacuum Ultraviolet Based Spectroscopy of the Actinides

The subjects of discussion included: VUV photoelectron spectroscopy, X-ray photoelectron spectroscopy, Synchrotron-radiation-based photoelectron spectroscopy, Soft x-ray absorption spectroscopy, Soft x-ray emission spectroscopy, Inverse photoelectron spectroscopy, Bremstrahlung Isochromat Spectroscopy, Low energy IPES, Resonant inverse photoelectron spectroscopy.
Date: March 17, 2011
Creator: Tobin, J. G.
Object Type: Article
System: The UNT Digital Library
Wakefield Calculations for the LCLS in Multbunch Operation (open access)

Wakefield Calculations for the LCLS in Multbunch Operation

Normally the Linac Coherent Light Source (LCLS) operates in single-bunch mode, sending a bunch of up to 250 pC charge at 120 Hz through the linac and the undulator, and the resulting FEL radiation into one of the experimental hutches. With two bunches per rf pulse, each pulse could feed either two experiments or one experiment in a pump-probe type configuration. Two-bunch FEL operation has already been briefly tested at the LCLS, and works reasonably well, although not yet routinely. In this report we study the longitudinal and transverse long-range (bunch-to-bunch) wakefields of the linacs and their effects on LCLS performance in two-bunch mode, which is initially the most likely scenario. The longitudinal wake changes the average energy at the second bunch, and the transverse wake misaligns the second bunch (in transverse phase space) in the presence of e.g. transverse injection jitter or quad misalignments. Finally, we extend the study to consider the LCLS with trains of up to 20 bunches per rf pulse. In the LCLS the bunch is created in an rf gun, and then passes in sequence through Linac 0, Linac 1, Linac X, Bunch Compressor 1 (BC 1), Linac 2, BC 2, Linac 3, and finally …
Date: October 17, 2011
Creator: Bane, K.
Object Type: Article
System: The UNT Digital Library
The Role of Eddy-Tansport in the Thermohaline Circulation (open access)

The Role of Eddy-Tansport in the Thermohaline Circulation

Several research themes were developed during the course of this project. (1) Low-frequency oceanic varibility; (2) The role of eddies in the Antarctic Circumpolar Current (ACC) region; (3) Deep stratification and the overturning circulation. The key findings were as follows: (1) The stratification below the main thermocline (at about 500m) is determined in the circumpolar region and then communicated to the enclosed portions of the oceans through the overturning circulation. (2) An Atlantic pole-to-pole overturning circulation can be maintained with very small interior mixing as long as surface buoyancy values are shared between the northern North Atlantic and the ACC region.
Date: November 17, 2011
Creator: Cessi, Dr. Paola
Object Type: Report
System: The UNT Digital Library
Inclusive and Exclusive |Vub| (open access)

Inclusive and Exclusive |Vub|

The current status of the determinations of CKM matrix element |V{sub ub}| via exclusive and inclusive charmless semileptonic B decays is reviewed. The large datasets collected at the B-Factories, and the increased precision of theoretical calculations have allowed an improvement in the determination of |V{sub ub}|. However, there are still significant uncertainties. In the exclusive approach, the most precise measurement of the pion channel branching ratio is obtained by an untagged analysis. This very good precision can be reached by tagged analyses with more data. The problem with exclusive decays is that the strong hadron dynamics can not be calculated from first principles and the determination of the form factor has to rely on light-cone sum rules or lattice QCD calculations. The current data samples allow a comparison of different FF models with data distributions. With further developments on lattice calculations, the theoretical error should shrink to reach the experimental one. The inclusive approach still provides the most precise |V{sub ub}| determinations. With new theoretical calculations, the mild (2.5{sigma}) discrepancy with respect to the |V{sub ub}| value determined from the global UT fit has been reduced. As in the exclusive approach, theoretical uncertainties represent the limiting factor to the precision …
Date: November 17, 2011
Creator: Petrella, Antonio
Object Type: Article
System: The UNT Digital Library
International Conference on Surface X-ray and Neutron Scattering (SXNS-11) (open access)

International Conference on Surface X-ray and Neutron Scattering (SXNS-11)

The 11th International Surface X-ray and Neutron Scattering (SXNS) Conference was held on July 13-17, 2010, on the Northwestern University (NU) campus, in Evanston Illinois and hosted by the NU Materials Research Science and Engineering Center. This biennial conference brought together a community of 164 attendees from 16 countries. The field now makes use of a broad range of new experimental capabilities that have been made possible through the development of increasingly brilliant X-ray and neutron sources around the world, including third generation synchrotron sources, neutron reactor and spallation sources, as well as the recent development of X-ray lasers.
Date: June 17, 2011
Creator: Bedzyk, Michael J.
Object Type: Report
System: The UNT Digital Library
TANK48 CFD MODELING ANALYSIS (open access)

TANK48 CFD MODELING ANALYSIS

The process of recovering the waste in storage tanks at the Savannah River Site (SRS) typically requires mixing the contents of the tank to ensure uniformity of the discharge stream. Mixing is accomplished with one to four dual-nozzle slurry pumps located within the tank liquid. For the work, a Tank 48 simulation model with a maximum of four slurry pumps in operation has been developed to estimate flow patterns for efficient solid mixing. The modeling calculations were performed by using two modeling approaches. One approach is a single-phase Computational Fluid Dynamics (CFD) model to evaluate the flow patterns and qualitative mixing behaviors for a range of different modeling conditions since the model was previously benchmarked against the test results. The other is a two-phase CFD model to estimate solid concentrations in a quantitative way by solving the Eulerian governing equations for the continuous fluid and discrete solid phases over the entire fluid domain of Tank 48. The two-phase results should be considered as the preliminary scoping calculations since the model was not validated against the test results yet. A series of sensitivity calculations for different numbers of pumps and operating conditions has been performed to provide operational guidance for solids …
Date: May 17, 2011
Creator: Lee, S.
Object Type: Report
System: The UNT Digital Library
Single-shot measurement of the spectral envelope of broad-bandwidth terahertz pulses from femtosecond electron bunches (open access)

Single-shot measurement of the spectral envelope of broad-bandwidth terahertz pulses from femtosecond electron bunches

We present a new approach (demonstrated experimentally and through modeling) to characterize the spectral envelope of a terahertz (THz) pulse in a single shot. The coherent THz pulse is produced by a femtosecond electron bunch and contains information on the bunch duration. The technique, involving a single low-power laser probe pulse, is an extension of the conventional spectral encoding method (limited in time resolution to hundreds of femtoseconds) into a regime only limited in resolution by the laser pulse length (tens of femtoseconds). While only the bunch duration is retrieved (and not the exact charge profile), such a measurement provides a useful and critical parameter for optimization of the electron accelerator.
Date: June 17, 2011
Creator: van Tilborg, Jeroen; Toth, Csaba; Matlis, Nicholas; Plateau, Guillaume & Leemans, Wim
Object Type: Article
System: The UNT Digital Library
Development & Optimization of Materials and Processes for a Cost Effective Photoelectrochemical Hydrogen Production System (open access)

Development & Optimization of Materials and Processes for a Cost Effective Photoelectrochemical Hydrogen Production System

The overall project objective was to apply high throughput experimentation and combinatorial methods together with novel syntheses to discover and optimize efficient, practical, and economically sustainable materials for photoelectrochemical production of bulk hydrogen from water. Automated electrochemical synthesis and photoelectrochemical screening systems were designed and constructed and used to study a variety of new photoelectrocatalytic materials. We evaluated photocatalytic performance in the dark and under illumination with or without applied bias in a high-throughput manner and did detailed evaluation on many materials. Significant attention was given to -Fe2O3 based semiconductor materials and thin films with different dopants were synthesized by co-electrodeposition techniques. Approximately 30 dopants including Al, Zn, Cu, Ni, Co, Cr, Mo, Ti, Pt, etc. were investigated. Hematite thin films doped with Al, Ti, Pt, Cr, and Mo exhibited significant improvements in efficiency for photoelectrochemical water splitting compared with undoped hematite. In several cases we collaborated with theorists who used density functional theory to help explain performance trends and suggest new materials. The best materials were investigated in detail by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visual spectroscopy (UV-Vis), X-ray photoelectron spectroscopy (XPS). The photoelectrocatalytic performance of the thin films was evaluated and their incident photon
Date: January 17, 2011
Creator: McFarland, Eric W.
Object Type: Text
System: The UNT Digital Library
Aging Studies of VCE Dismantlement Returns (open access)

Aging Studies of VCE Dismantlement Returns

VCE is an ethylene/vinyl acetate/vinyl alcohol terpolymer binder for filled elastomers which is designed to accept high filler loadings. Filled elastomer parts consist of the binder (VCE), a curing agent (Hylene MP, diphenol-4-4{prime}-methylenebis(phenylcarbamate)), a processing aid (LS, lithium stearate), and filler particles (typically 70% fraction by weight). The curing of the filled elastomer parts occurs from the heat-activated reaction between the hydroxyl groups of VCE with the Hylene MP curing agent, resulting in a cross-linked network. The final vinyl acetate content is typically between 34.9 and 37.9%, while the vinyl alcohol content is typically between 1.27 and 1.78%. Surveillance data for this material is both scarce and scattered, complicating the assessment of any aging trends in systems. In addition, most of the initial surveillance efforts focused on mechanical properties such as hardness and tensile strength, and chemical information is therefore lacking. Material characterization and aging studies had been performed on previous formulations of the VCE material but the Ethylene Vinyl Acetate (EVA) starting copolymer is no longer commercially available. New formulations with replacement EVA materials are currently being established and will require characterization as well as updated aging models.
Date: October 17, 2011
Creator: Letant, S; Alviso, C; Pearson, M; Albo, R; Small, W; Wilson, T et al.
Object Type: Report
System: The UNT Digital Library
Probing the Linear Polarization of Gluons in Unpolarized Hadrons at EIC (open access)

Probing the Linear Polarization of Gluons in Unpolarized Hadrons at EIC

Gluons inside unpolarized hadrons can be linearly polarized provided they have a nonzero transverse momentum. The simplest and theoretically safest way to probe this TMD distribution of linearly polarized gluons is through cos 2{phi} asymmetries in heavy quark pair or dijet production in electron-hadron collisions. Future EIC or LHeC experiments are ideally suited for this purpose. Here we estimate the maximum asymmetries for EIC kinematics.
Date: August 17, 2011
Creator: Boer, Daniel; Brodsky, Stanley J.; Mulders, Piet J. & Pisano, Cristian
Object Type: Article
System: The UNT Digital Library