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Activation of Air and Utilities in the National Ignition Facility (open access)

Activation of Air and Utilities in the National Ignition Facility

Detailed 3-D modeling of the NIF facility is developed to accurately simulate the radiation environment within the NIF. Neutrons streaming outside the NIF Target Chamber will activate the air present inside the Target Bay and the Ar gas inside the laser tubes. Smaller levels of activity are also generated in the Switchyard air and in the Ar portion of the SY laser beam path. The impact of neutron activation of utilities located inside the Target Bay is analyzed for variety of shot types. The impact of activating TB utilities on dose received by maintenance personnel post-shot is analyzed. The current NIF facility model includes all important features of the Target Chamber, shielding system, and building configuration. Flow of activated air from the Target Bay is controlled by the HVAC system. The amount of activated Target Bay air released through the stack is very small and does not pose significant hazard to personnel or the environment. Activation of Switchyard air is negligible. Activation of Target Bay utilities result in a manageable dose rate environment post high yield (20 MJ) shots. The levels of activation generated in air and utilities during D-D and THD shots are small and do not impact work …
Date: April 8, 2010
Creator: Khater, H; Pohl, B & Brererton, S
System: The UNT Digital Library
Actual Waste Testing With a Single Disk Spintek Rotary Microfilter (open access)

Actual Waste Testing With a Single Disk Spintek Rotary Microfilter

This report is a descriptive account on the Actual Waste Testing With a Single Disk Spintek Rotary Microfilter
Date: March 8, 2010
Creator: Huber, H. J.
System: The UNT Digital Library
AFFECTS OF MECHANICAL MILLING AND METAL OXIDE ADDITIVES ON SORPTION KINETICS OF 1:1 LiNH2/MgH2 MIXTURE (open access)

AFFECTS OF MECHANICAL MILLING AND METAL OXIDE ADDITIVES ON SORPTION KINETICS OF 1:1 LiNH2/MgH2 MIXTURE

The destabilized complex hydride system composed of LiNH{sub 2}:MgH{sub 2} (1:1 molar ratio) is one of the leading candidates of hydrogen storage with a reversible hydrogen storage capacity of 8.1 wt%. A low sorption enthalpy of {approx}32 kJ/mole H{sub 2} was first predicted by Alapati et al. utilizing first principle density function theory (DFT) calculations and has been subsequently confirmed empirically by Lu et al. through differential thermal analysis (DTA). This enthalpy suggests that favorable sorption kinetics should be obtainable at temperatures in the range of 160 C to 200 C. Preliminary experiments reported in the literature indicate that sorption kinetics are substantially lower than expected in this temperature range despite favorable thermodynamics. Systematic isothermal and isobaric sorption experiments were performed using a Sievert's apparatus to form a baseline data set by which to compare kinetic results over the pressure and temperature range anticipated for use of this material as a hydrogen storage media. Various material preparation methods and compositional modifications were performed in attempts to increase the kinetics while lowering the sorption temperatures. This paper outlines the results of these systematic tests and describes a number of beneficial additions which influence kinetics as well as NH{sub 3} formation.
Date: December 8, 2010
Creator: Erdy, C.; Anton, D. & Gray, J.
System: The UNT Digital Library
Carrier-Envelope Phase Effect on Atomic Excitation by Few-Cycle rf Pulses (open access)

Carrier-Envelope Phase Effect on Atomic Excitation by Few-Cycle rf Pulses

Article on carrier-envelope phase effect on atomic excitation by few-cycle rf pulses.
Date: March 8, 2010
Creator: Li, Hebin; Sautenkov, Vladimir A.; Rostovtsev, Yuri V.; Kash, Michael M.; Anisimov, Petr M.; Welch, George R. et al.
System: The UNT Digital Library
CERTS Microgrid Laboratory Test Bed (open access)

CERTS Microgrid Laboratory Test Bed

The objective of the CERTS Microgrid Test Bed project was to enhance the ease of integrating energy sources into a microgrid. The project accomplished this objective by developing and demonstrating three advanced techniques, collectively referred to as the CERTS Microgrid concept, that significantly reduce the level of custom field engineering needed to operate microgrids consisting of generating sources less than 100kW. The techniques comprising the CERTS Microgrid concept are: 1 a method for effecting automatic and seamless transitions between grid-connected and islanded modes of operation, islanding the microgrid's load from a disturbance, thereby maintaining a higher level of service, without impacting the integrity of the utility's electrical power grid; 2 an approach to electrical protection within a limited source microgrid that does not depend on high fault currents; and 3 a method for microgrid control that achieves voltage and frequency stability under islanded conditions without requiring high-speed communications between sources.
Date: June 8, 2010
Creator: ETO, J.; LASSETER, R.; SCHENKMAN, B.; STEVENS, J.; KLAPP, D.; VOLKOMMER, H. et al.
System: The UNT Digital Library
CERTS Microgrid Laboratory Test Bed (open access)

CERTS Microgrid Laboratory Test Bed

CERTS Microgrid concept captures the emerging potential of distributed generation using a system approach. CERTS views generation and associated loads as a subsystem or a 'microgrid'. The sources can operate in parallel to the grid or can operate in island, providing UPS services. The system can disconnect from the utility during large events (i.e. faults, voltage collapses), but may also intentionally disconnect when the quality of power from the grid falls below certain standards. CERTS Microgrid concepts were demonstrated at a full-scale test bed built near Columbus, Ohio and operated by American Electric Power. The testing fully confirmed earlier research that had been conducted initially through analytical simulations, then through laboratory emulations, and finally through factory acceptance testing of individual microgrid components. The islanding and resynchronization method met all Institute of Electrical and Electronics Engineers Standard 1547 and power quality requirements. The electrical protection system was able to distinguish between normal and faulted operation. The controls were found to be robust under all conditions, including difficult motor starts and high impedance faults.
Date: June 8, 2010
Creator: Lasseter, R. H.; Eto, J. H.; Schenkman, B.; Stevens, J.; Volkmmer, H.; Klapp, D. et al.
System: The UNT Digital Library
E-Cloud Effects on Singe-Bunch Dynamics in the Proposed PS2 (open access)

E-Cloud Effects on Singe-Bunch Dynamics in the Proposed PS2

One of the options considered for future upgrades of the LHC injector complex entails the replacement of the PSwith the PS2, a longer circumference and higher energy synchrotron. Electron cloud effects represent an importantpotential limitation to the achievement of the upgrade goals. We report the results of numerical studies aimingat estimating the e-cloud density thresholds for the occurrence of single bunch instabilities.
Date: October 8, 2010
Creator: Venturini, M.; Furman, M. & Vay, J. L.
System: The UNT Digital Library
CO2 Capture with Enzyme Synthetic Analogue (open access)

CO2 Capture with Enzyme Synthetic Analogue

Overview of an ongoing, 2 year research project partially funded by APRA-E to create a novel, synthetic analogue of carbonic anhydrase and incorporate it into a membrane for removal of CO2 from flue gas in coal power plants. Mechanism background, preliminary feasibility study results, molecular modeling of analogue-CO2 interaction, and program timeline are provided.
Date: November 8, 2010
Creator: Cordatos, Harry
System: The UNT Digital Library
Comparing Vacuum and Extreme Ultraviolet Radiation for Postionization of Laser Desorbed Neutrals from Bacterial Biofilms and Organic Fullerene (open access)

Comparing Vacuum and Extreme Ultraviolet Radiation for Postionization of Laser Desorbed Neutrals from Bacterial Biofilms and Organic Fullerene

Vacuum and extreme ultraviolet radiation from 8 - 24 eV generated at a synchrotron was used to postionize laser desorbed neutrals of antibiotic-treated biofilms and a modified fullerene using laser desorption postionization mass spectrometry (LDPI-MS). Results show detection of the parent ion, various fragments, and extracellular material from biofilms using LDPI-MS with both vacuum and extreme ultraviolet photons. Parent ions were observed for both cases, but extreme ultraviolet photons (16-24 eV) induced more fragmentation than vacuum ultraviolet (8-14 eV) photons.
Date: December 8, 2010
Creator: Gaspera, Gerald L.; Takahashi, Lynelle K.; Zhou, Jia; Ahmed, Musahid; Moored, Jerry F. & Hanley, Luke
System: The UNT Digital Library
Controlled incorporation of mid-to-high Z transition metals in CVD diamond (open access)

Controlled incorporation of mid-to-high Z transition metals in CVD diamond

We report on a general method to fabricate transition metal related defects in diamond. Controlled incorporation of Mo and W in synthetic CVD diamond was achieved by adding volatile metal precursors to the diamond chemical vapor deposition (CVD) growth process. Effects of deposition temperature, grain structure and precursor exposure on the doping level were systematically studied, and doping levels of up to 0.25 at.% have been achieved. The metal atoms are uniformly distributed throughout the diamond grains without any indication of inclusion formation. These results are discussed in context of the kinetically controlled growth process of CVD diamond.
Date: January 8, 2010
Creator: Biener, M M; Biener, J; Kucheyev, S O; Wang, Y M; El-Dasher, B; Teslich, N E et al.
System: The UNT Digital Library
Coupling Visualization and Data Analysis for Knowledge Discovery from Multi-dimensional Scientific Data (open access)

Coupling Visualization and Data Analysis for Knowledge Discovery from Multi-dimensional Scientific Data

Knowledge discovery from large and complex scientific data is a challenging task. With the ability to measure and simulate more processes at increasingly finer spatial and temporal scales, the growing number of data dimensions and data objects presents tremendous challenges for effective data analysis and data exploration methods and tools. The combination and close integration of methods from scientific visualization, information visualization, automated data analysis, and other enabling technologies"such as efficient data management" supports knowledge discovery from multi-dimensional scientific data. This paper surveys two distinct applications in developmental biology and accelerator physics, illustrating the effectiveness of the described approach.
Date: June 8, 2010
Creator: Rubel, Oliver; Ahern, Sean; Bethel, E. Wes; Biggin, Mark D.; Childs, Hank; Cormier-Michel, Estelle et al.
System: The UNT Digital Library
Deflagration Rate Measurements of Three Insensitive High Explosives: LLM-105, TATB, and DAAF (open access)

Deflagration Rate Measurements of Three Insensitive High Explosives: LLM-105, TATB, and DAAF

The pressure dependent deflagration rates of LLM-105, DAAF and TATB based formulations were measured in the LLNL high pressure strand burner. The role of binder amount, explosive type, and thermal damage and their effects on the deflagration rate will be discussed. One DAAF formulation, two different formulations of LLM-105, and four formulations of TATB were studied; results indicate that binder amount and type play a minor role in the deflagration behavior. This is in sharp contrast to the HMX based formulations which strongly depend on binder amount and type. The effect of preheating these samples was considerably more dramatic. In the case of LLM-105, preheating the sample appears to have little effect on the deflagration rate. In contrast, preheating DAAF and TATB formulations causes the deflagration rate to accelerate. The thermal and mechanical properties of these formulations will be discussed in the context of their pressure and temperature dependent deflagration rates.
Date: March 8, 2010
Creator: Glascoe, E A; Maienschein, J L; Lorenz, K T; Tan, N & Koerner, J G
System: The UNT Digital Library
DENSITY-FUNCTIONAL STUDY OF BCC Pu-U, Pu-Np, Pu-Am, AND Pu-Cm ALLOYS (open access)

DENSITY-FUNCTIONAL STUDY OF BCC Pu-U, Pu-Np, Pu-Am, AND Pu-Cm ALLOYS

None
Date: July 8, 2010
Creator: Landa, A; Soderlind, P; Turchi, P E; Vitos, L; Peil, O E & Ruban, A V
System: The UNT Digital Library
Design and Measurement of a Cu L-edge X-ray Filter for FEL-Pumped X-ray Laser Experiments (open access)

Design and Measurement of a Cu L-edge X-ray Filter for FEL-Pumped X-ray Laser Experiments

None
Date: June 8, 2010
Creator: Dunn, J.; London, R. A.; Cone, K. V.; Rocca, J. J. & Rohringer, N.
System: The UNT Digital Library
Detonation Failure in Small Cylindrical LX-17 Charges (open access)

Detonation Failure in Small Cylindrical LX-17 Charges

None
Date: March 8, 2010
Creator: Lorenz, K. T.; Hare, D. E.; Vitello, P.; Souers, P. C.; Chambers, R. & Lee, E. L.
System: The UNT Digital Library
Development of an Atomic Force Microscope (open access)

Development of an Atomic Force Microscope

None
Date: February 8, 2010
Creator: Obrebski, J W; Buice, E S & Munnig Schmidt, R H
System: The UNT Digital Library
Discovery, SAR, and Radiolabeling of Halogenated Benzimidazole Carboxamide Antagonists as Useful Tools for (alpha)4(beta)1 Integrin Expressed on T- and B-cell Lymphomas (open access)

Discovery, SAR, and Radiolabeling of Halogenated Benzimidazole Carboxamide Antagonists as Useful Tools for (alpha)4(beta)1 Integrin Expressed on T- and B-cell Lymphomas

The cell surface receptor {alpha}{sub 4}{beta}{sub 1} integrin is an attractive yet poorly understood target for selective diagnosis and treatment of T- and B-cell lymphomas. This report focuses on the rapid microwave preparation of medicinally pertinent benzimidazole heterocycles, structure-activity relationships (SAR) of novel halobenzimidazole carboxamide antagonists 3-6, and preliminary biological evaluation of radioiodinated agents 7, 8, and 18. The I-125 derivative 18 had good tumor uptake (12 {+-} 1% ID/g at 24 h; 4.5 {+-} 1% ID/g at 48 h) and tumor:kidney ratio ({approx}4:1 at 24 h; 2.5:1 at 48 h) in xenograft murine models of B-cell lymphoma. Molecular homology models of {alpha}{sub 4}{beta}{sub 1} integrin have predicted that docked halobenzimidazole carboxamides have the halogen atom in a suitable orientation for halogen-hydrogen bonding. These high affinity ({approx} pM binding) halogenated ligands are attractive tools for medicinal and biological use; the fluoro and iodo derivatives are potential radiodiagnostic ({sup 18}F) or radiotherapeutic ({sup 131}I) agents, whereas the chloro and bromo analogues could provide structural insight into integrin-ligand interactions through photoaffinity cross-linking/mass spectroscopy experiments, as well as co-crystallization X-ray studies.
Date: February 8, 2010
Creator: Carpenter, R. D.; Natarajan, A.; Lau, E. Y.; Andrei, M.; Solano, D. M.; Lightstone, F. C. et al.
System: The UNT Digital Library
Electrodeposition of U and Pu on Thin C and Ti Subtrates INTDS 2010 Conference Proceedings (open access)

Electrodeposition of U and Pu on Thin C and Ti Subtrates INTDS 2010 Conference Proceedings

None
Date: September 8, 2010
Creator: Henderson, R. A.; Gostic, J. M.; Burke, J. T.; Fisher, S. E. & Wu, C. Y.
System: The UNT Digital Library
Electron-Cloud Build-Up: Theory and Data (open access)

Electron-Cloud Build-Up: Theory and Data

We present a broad-brush survey of the phenomenology, history and importance of the electron-cloud effect (ECE). We briefly discuss the simulation techniques used to quantify the electron-cloud (EC) dynamics. Finally, we present in more detail an effective theory to describe the EC density build-up in terms of a few effective parameters. For further details, the reader is encouraged to refer to the proceedings of many prior workshops, either dedicated to EC or with significant EC contents, including the entire 'ECLOUD' series. In addition, the proceedings of the various flavors of Particle Accelerator Conferences contain a large number of EC-related publications. The ICFA Beam Dynamics Newsletter series contains one dedicated issue, and several occasional articles, on EC. An extensive reference database is the LHC website on EC.
Date: October 8, 2010
Creator: Furman, M. A.
System: The UNT Digital Library
Electronic and magnetic structure of GaxFe1-x thin films (open access)

Electronic and magnetic structure of GaxFe1-x thin films

The electronic as well as magnetic properties of Ga{sub x}Fe{sub 1-x} films were studied by soft x-ray measurements. Using x-ray magnetic circular dichroism the Fe majority-spin band was found to be completely filled for x {approx} 0.3. With further enhanced Ga content, the Fe moment as well as the angular dependence of the x-ray magnetic linear dichroism decrease strongly, which we attribute to the formation of D0{sub 3} precipitates. Moreover, the magnetocrystalline anisotropy drops significantly.
Date: September 8, 2010
Creator: Arenholz, E.; van der Laan, G.; McClure, A. & Idzerda, Y.
System: The UNT Digital Library
Endomicroscopy imaging of epithelial structure using tissue autofluorescence (open access)

Endomicroscopy imaging of epithelial structure using tissue autofluorescence

None
Date: July 8, 2010
Creator: Lin, B; Urayama, S; Saroufeem, R M; Matthews, D L & Demos, S G
System: The UNT Digital Library
EUV spectroscopy of high-redshift x-ray objects (open access)

EUV spectroscopy of high-redshift x-ray objects

None
Date: June 8, 2010
Creator: Kowalski, M. P.; Wolff, M. T.; Wood, K. S.; Barbee, T. W. & Barstow, M. A.
System: The UNT Digital Library
Evidence for plasma phase transition in high pressure hydrogen from ab-initio simulations (open access)

Evidence for plasma phase transition in high pressure hydrogen from ab-initio simulations

We have performed a detailed study of molecular dissociation in liquid hydrogen using both Born-Oppenheimer molecular dynamics with Density Functional Theory and Coupled Electron-Ion Monte Carlo simulations. We observe a range of densities where (dP/d{rho}){sub T} = 0 that coincides with sharp discontinuities in the electronic conductivity, which is clear evidence of the plasma phase transition for temperatures 600K {le} T {le} 1500K. Both levels of theory exhibit the transition, although Quantum Monte Carlo predicts higher transition pressures. Based on the temperature dependence of the discontinuity in the electronic conductivity, we estimate the critical point of the transition at temperatures slightly below 2000 K. We examine the influence of proton zero point motion by using Path Integral Molecular Dynamics with Density Functional Theory; the main effect is to shift the transition to lower pressures. Furthermore, we calculate the melting curve of molecular hydrogen up to pressures of 200 GPa, finding a reentrant melting line in good agreement with previous calculations. The melting line crosses the metalization line at 700 K and 220 GPa using density functional energetics and at 550 K and 290 GPa using Quantum Monte Carlo energetics.
Date: February 8, 2010
Creator: Morales, M; Pierleoni, C; Schwegler, E & Ceperley, D
System: The UNT Digital Library
Extracting Short Rise-Time Velocity Profiles with Digital Down-Shift Analysis of Optically Up-Converted PDV Data (open access)

Extracting Short Rise-Time Velocity Profiles with Digital Down-Shift Analysis of Optically Up-Converted PDV Data

This work describes the digital down-shift (DDS) technique, a new method of extracting short rise-time velocity profiles in the analysis of optically up-converted PDV data. The DDS technique manipulates the PDV data by subtracting a constant velocity (i.e., the DDS velocity νDDS) from the velocity profile. DDS exploits the simple fact that the optically up-converted data ride on top of a base velocity (ν0, the apparent velocity at no motion) with a rapid rise to a high velocity (νf) of a few km/s or more. Consequently, the frequency content of the signal must describe a velocity profile that increases from ν0 to ν0 + νf. The DDS technique produces velocity reversals in the processed data before shock breakout when ν0 < νDDS < ν0 + νf. The DDS analysis process strategically selects specific DDS velocities (velocity at which the user down shifts the data) that produce anomalous reversals (maxima and/or minima), which are predictable and easy to identify in the mid-range of the data. Additional analysis determines when these maxima and minima occur. By successive application of the DDS technique and iterative analysis, velocity profiles are extracted as time as a function of velocity rather than as a function of …
Date: September 8, 2010
Creator: Abel Diaz, Nathan Riley, Cenobio Gallegos, Matthew Teel, Michael Berninger, Thomas W. Tunnell
System: The UNT Digital Library