1,2- Hydroxypyridonates as Contrast Agents for Magnetic ResonanceImaging: TREN-1,2-HOPO (open access)

1,2- Hydroxypyridonates as Contrast Agents for Magnetic ResonanceImaging: TREN-1,2-HOPO

1,2-Hydroxypyridinones (1,2-HOPO) form very stable lanthanide complexes that may be useful as contrast agents for Magnetic Resonance Imaging (MRI). X-ray diffraction of single crystals established that the solid state structures of the Eu(III) and the previously reported [Inorg. Chem. 2004, 43, 5452] Gd(III) complex are identical. The recently discovered sensitizing properties of 1,2-HOPO chelates for Eu(III) luminescence allow direct measurement of the number if water molecules in the metal complex. Fluorescence measurements of the Eu(III) complex corroborate that in solution two water molecules coordinate the lanthanide (q = 2) as proposed from the analysis of NMRD profiles. In addition, fluorescence measurements have verified the anion binding interactions of lanthanide TREN-1,2-HOPO complexes in solution, studied by relaxivity, revealing only very weak oxalate binding (K{sub A} = 82.7 {+-} 6.5 M{sup -1}). Solution thermodynamic studies of the metal complex and free ligand have been carried out using potentiometry, spectrophotometry and fluorescence spectroscopy. The metal ion selectivity of TREN-1,2-HOPO supports the feasibility of using 1,2-HOPO ligands for selective lanthanide binding [pGd = 19.3 (2); pZn = 15.2 (2), pCa = 8.8 (3)].
Date: May 8, 2007
Creator: Jocher, Christoph J.; Moore, Evan G.; Xu, Jide; Avedano, Stefano; Botta, Mauro; Aime, Silvio et al.
System: The UNT Digital Library
1/5-scale experiment of a Mark I boiling-water reactor pressure-suppression system under hypothetical LOCA conditions (open access)

1/5-scale experiment of a Mark I boiling-water reactor pressure-suppression system under hypothetical LOCA conditions

Experimental results show the sensitivity of hydrodynamically generated vertical loads to changes in the drywell pressurization rate, downcomer submergence, and vent-line loss coefficient. Insignificant effects on peak vertical loads were observed when the vent-line loss was varied. Peak vertical loads can be reduced by adding initial drywell overpressure so that the downcomers are partly cleared of water. Spatial variation of pressure at about the time of vent clearing is seen in comparisons of data from locations along the axis of the toroidal wetwell.
Date: July 8, 1977
Creator: Pitts, J. H. & McCauley, E. W.
System: The UNT Digital Library
3-D Silicon Photonic Lattices- Cornerstone of an Emerging Photonics Revolution (open access)

3-D Silicon Photonic Lattices- Cornerstone of an Emerging Photonics Revolution

Three-dimensional photonic lattices are engineered materials which are the photonic analogues of semiconductors. These structures were first proposed and demonstrated in the mid-to-late 1980's. However, due to fabrication difficulties, lattices active in the infrared are only just emerging. Wide ranges of structures and fabrication approaches have been investigated. The most promising approach for many potential applications is a diamond-like structure fabricated using silicon microprocessing techniques. This approach has enabled the fabrication of 3-D silicon photonic lattices active in the infrared. The structures display band gaps centered from 12{micro} down to 1.55{micro}.
Date: July 8, 1999
Creator: Fleming, J.G. & Lin, Shawn-Yu
System: The UNT Digital Library
A 4 GSa/s Instability Feedback Processing System for Intra-Bunch Instabilities (open access)

A 4 GSa/s Instability Feedback Processing System for Intra-Bunch Instabilities

None
Date: November 8, 2013
Creator: Dusatko, J.; Cesaratto, J. M.; Fox, J. D.; Pollock, K.; Rivetta, C. H.; Turgut, O. et al.
System: The UNT Digital Library
(6)Li, (7)Li Nuclear Magnetic Resonance Investigation of Lithium Coordination in Binary Phosphate Glasses (open access)

(6)Li, (7)Li Nuclear Magnetic Resonance Investigation of Lithium Coordination in Binary Phosphate Glasses

{sup 6}Li and {sup 7}Li solid state magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy has been used to investigate the local coordination environment of lithium in a series of xLi{sub 2}O {center_dot} (1-x)P{sub 2}O{sub 5} glasses, where 0.05 {le} x {le} 0.55. Both the {sup 6}Li and {sup 7}Li show chemical shift variations with changes in the Li{sub 2}O concentration, but the observed {sup 6}Li NMR chemical shifts closely approximate the true isotropic chemical shift and can provide a measure of the lithium bonding environment. The {sup 6}Li NMR results indicate that in this series of lithium phosphate glasses the Li atoms have an average coordination between four and five. The results for the metaphosphate glass agree with the coordination number and range of chemical shifts observed for crystalline LiPO{sub 3}. An increase in the {sup 6}Li NMR chemical shift with increasing Li{sub 2}O content was observed for the entire concentration range investigated, correlating with increased cross-linking of the phosphate tetrahedral network by O-Li-O bridges. The {sup 6}Li chemical shifts were also observed to vary monotonically through the anomalous glass transition temperature (T{sub g}) minimum. This continuous chemical shift variation shows that abrupt changes in the Li coordination …
Date: February 8, 1999
Creator: Alam, T.M.; Boyle, T.J.; Brow, R.K. & Conzone, S.
System: The UNT Digital Library
THE 15 LAYER SILICON DRIFT DETECTOR TRACKER IN EXPERIMENT 896. (open access)

THE 15 LAYER SILICON DRIFT DETECTOR TRACKER IN EXPERIMENT 896.

Large linear silicon drift detectors have been developed and are in production for use in several experiments. Recently 15 detectors were used as a tracking device in BNL-AGS heavy ion experiment (E896). The detectors were successfully operated in a 6.2 T magnetic field. The behavior of the detectors, such as drift uniformity, resolution, and charge collection efficiency are presented. The effect of the environment on the detector performance is discussed. Some results from the experimental run are presented. The detectors performed well in an experimental environment. This is the first tracking application of these detectors.
Date: November 8, 1998
Creator: Pandy, S. U.
System: The UNT Digital Library
100 Femtosecond laser absorption in solid density targets (open access)

100 Femtosecond laser absorption in solid density targets

Experimental short pulse lasers are rapidly approaching energy levels where target irradiances exceeding 10{sup 20} W/CM{sup 2} are routinely achievable. These high intensity levels will open up a new class of solid target interaction physics where relativistic effects must be included and non-traditional absorption mechanisms become significant. However much remains to be understood of the absorption physics at lower intensities where classical absorption is dominated by collisional and resonance absorption. If attention is paid to producing clean laser pulses that do not significantly pre-pulse interact with the target, it is possible to produce plasmas of sufficiently short scale length that near-solid density interactions are observable at intensities exceeding 10{sup 18} W/CM{sup 2} for 100 fs laser irradiation. We report here extensions to our previous efforts at normal incidence that expand our observations to non-normal angles including the effect of polarization for several target materials. Between 10{sup 13} W/CM{sup 2} and 10{sup 14} W/CM{sup 2} we observe that the target absorption retains a signature of the intra-band atomic transitions. At higher intensities a more material independent ion-electron collisional absorption and short scale length resonance absorption dominate. P - polarized absorption in short scale length plasmas has been observed to exceed 60 …
Date: October 8, 1996
Creator: Price, D. F.; More, R. M.; Walling, R. S. & Stewart, R. E.
System: The UNT Digital Library
2004 Rock Deformation Gordon Conference - August 8-12, 2004 (open access)

2004 Rock Deformation Gordon Conference - August 8-12, 2004

Rock Deformation Gordon Conference Agenda and Final Report.
Date: August 8, 2004
Creator: Kronenberg, A. K.
System: The UNT Digital Library
2012 ELECTRONIC PROCESSES IN ORGANIC MATERIALS GORDON RESEARCH SEMINAR, JUNE 2-8, 2012 (open access)

2012 ELECTRONIC PROCESSES IN ORGANIC MATERIALS GORDON RESEARCH SEMINAR, JUNE 2-8, 2012

This meeting focuses on the latest progress and challenges regarding organic electronics devices, artificial light-harvesting systems, and inorganic/organic hybrid nanoscale systems and especially on the synergy between these fields.
Date: June 8, 2012
Creator: Eisele, Dorthe
System: The UNT Digital Library
2012 MULTIPHOTON PROCESSES GRC, JUNE 3-8, 2012 (open access)

2012 MULTIPHOTON PROCESSES GRC, JUNE 3-8, 2012

The sessions will focus on:  Attosecond science;  Strong-field processes in molecules and solids;  Generation of harmonics and attosecond pulses;  Free-electron laser experiments and theory;  Ultrafast imaging;  Applications of very high intensity lasers;  Propagation of intense laser fields.
Date: March 8, 2012
Creator: Walker, Barry
System: The UNT Digital Library
2013 Inorganic Reaction Mechanisms Gordon Research Conference (March 3-8, 2013 - Hotel Galvez, Galveston TX) (open access)

2013 Inorganic Reaction Mechanisms Gordon Research Conference (March 3-8, 2013 - Hotel Galvez, Galveston TX)

The 2013 Gordon Conference on Inorganic Reaction Mechanisms will present cutting-edge research on the molecular aspects of inorganic reactions involving elements from throughout the periodic table and state-of-the art techniques that are used in the elucidation of reaction mechanisms. The Conference will feature a wide range of topics, such as homogeneous and heterogeneous catalysis, metallobiochemistry, electron-transfer in energy reactions, polymerization, nitrogen fixation, green chemistry, oxidation, solar conversion, alkane functionalization, organotransition metal chemistry, and computational chemistry. The talks will cover themes of current interest including energy, materials, and bioinorganic chemistry. Sections cover: Electron-Transfer in Energy Reactions; Catalytic Polymerization and Oxidation Chemistry; Kinetics and Spectroscopy of Heterogeneous Catalysts; Metal-Organic Chemistry and its Application in Synthesis; Green Energy Conversion;Organometallic Chemistry and Activation of Small Molecules; Advances in Kinetics Modeling and Green Chemistry; Metals in Biology and Disease; Frontiers in Catalytic Bond Activation and Cleavage.
Date: December 8, 2012
Creator: Abu-Omar, Mahdi M.
System: The UNT Digital Library
A 3D Particle Simulation Code for Heavy Ion Fusion Accelerator Studies (open access)

A 3D Particle Simulation Code for Heavy Ion Fusion Accelerator Studies

We describe WARP, a new particle-in-cell code being developed and optimized for ion beam studies in true geometry. We seek to model transport around bends, axial compression with strong focusing, multiple beamlet interaction, and other inherently 3d processes that affect emittance growth. Constraints imposed by memory and running time are severe. Thus, we employ only two 3d field arrays ({rho} and {phi}), and difference {phi} directly on each particle to get E, rather than interpolating E from three meshes; use of a single 3d array is feasible. A new method for PIC simulation of bent beams follows the beam particles in a family of rotated laboratory frames, thus straightening'' the bends. We are also incorporating an envelope calculation, an (r, z) model, and 1d (axial) model within WARP. The BASIS development and run-time system is used, providing a powerful interactive environment in which the user has access to all variables in the code database. 10 refs., 3 figs.
Date: June 8, 1990
Creator: Friedman, A.; Bangerter, R. O.; Callahan, D. A.; Grote, D. P.; Langdon, A. B. & Haber, I.
System: The UNT Digital Library
5th Biotechnological Investigations Ocean Margins Program (open access)

5th Biotechnological Investigations Ocean Margins Program

BI-OMP supports DOE's mission in Climate Change Research. The program provides the fundamental understanding of the linkages between carbon and nitrogen cycles in ocean margins. Researchers are providing a mechanistic understanding of these cycles, using the tools of modern molecular biology. The models that will allow policy makers to determine safe levels of greenhouse gases for the Earth System.
Date: January 8, 2004
Creator: Massol, Arturo & Buxeda, Rosa
System: The UNT Digital Library
Ab Initio Many-Body Calculations of Deuteron-4He Scattering And 6Li States (open access)

Ab Initio Many-Body Calculations of Deuteron-4He Scattering And 6Li States

None
Date: February 8, 2011
Creator: Quaglioni, S & Navratil, P
System: The UNT Digital Library
AC Loss Analysis on the Superconducting Coupling Magnet in MICE (open access)

AC Loss Analysis on the Superconducting Coupling Magnet in MICE

A pair of coupling solenoids is used in MICE experiment to generate magnetic field which keeps the muons within the iris of thin RF cavity windows. The coupling solenoids have a 1.5-meter inner diameter and will produce 7.4 T peak magnetic field. Three types of AC losses in coupling solenoid are discussed. The affect of AC losses on the temperature distribution within the cold mass during charging and rapid discharging process is analyzed also. The analysis result will be further confirmed by the experiment of the prototype solenoid for coupling solenoid, which will be designed, fabricated and tested at ICST.
Date: July 8, 2008
Creator: Wu, Hong; Wang, Li; Green, Michael; Li, LanKai; Xu, FengYu; Liu, XiaoKun et al.
System: The UNT Digital Library
Accelerated Exposure Tests of Encapsulated Si Solar Cells and Encapsulation Materials (open access)

Accelerated Exposure Tests of Encapsulated Si Solar Cells and Encapsulation Materials

We have conducted a series of accelerated exposure test (AET) studies for various crystalline-Si (c-Si) and amorphous-Si (a-Si) cell samples that were encapsulated with different superstrates, pottants, and substrates. Nonuniform browning patterns of ethylene vinyl acetate (EVA) pottants were observed for glass/EVA/glass-encapsulated c-Si cell samples under solar simulator exposures at elevated temperatures. The polymer/polymer-configured laminates with Tedlar or Tefzel did not discolor because of photobleaching reactions, but yellowed with polyester or nylon top films. Delamination was observed for the polyester/EVA layers on a-Si minimodules and for a polyolefin-based thermoplastic pottant at high temperatures. For all tested c-Si cell samples, irregular changes in the current-voltage parameters were observed that could not be accounted for simply by the transmittance changes of the superstrate/pottant layers. Silicone-type adhesives used under UV-transmitting polymer top films were observed to cause greater cell current/efficiency loss than EVA or polyethylene pottants.
Date: October 8, 1998
Creator: Pern, F. J. & Glick, S. H.
System: The UNT Digital Library
Acceleration and deceleration phase nonlinear Rayleigh-Taylor growth at spherical interfaces (open access)

Acceleration and deceleration phase nonlinear Rayleigh-Taylor growth at spherical interfaces

The Layzer model for the nonlinear evolution of bubbles in the Rayleigh-Taylor instability has recently been generalized to the case of spherically imploding interfaces [D. S. Clark and M. Tabak, to appear, PRE (2005).]. The spherical case is more relevant to, e.g., inertial confinement fusion or various astrophysical phenomena when the convergence is strong or the perturbation wavelength is comparable to the interface curvature. Here, the model is further extended to the case of bubble growth during the deceleration (stagnation) phase of a spherical implosion and to the growth of spikes during both the acceleration and deceleration phases. Differences in the nonlinear growth rates for both bubbles and spikes are found when compared with planar results. The model predictions are verified by comparison with numerical hydrodynamics simulations.
Date: April 8, 2005
Creator: Clark, D S & Tabak, M
System: The UNT Digital Library
Acceleration of Amide Bond Rotation by Encapsulation in the Hydrophobic Interior of a Water-Soluble Supramolecular Assembly (open access)

Acceleration of Amide Bond Rotation by Encapsulation in the Hydrophobic Interior of a Water-Soluble Supramolecular Assembly

The hydrophobic interior cavity of a self-assembled supramolecular assembly exploits the hydrophobic effect for the encapsulation of tertiary amides. Variable temperature 1H NMR experiments reveal that the free energy barrier for rotation around the C-N amide bond is lowered by up to 3.6 kcal/mol upon encapsulation. The hydrophobic cavity of the assembly is able to stabilize the less polar transition state of the amide rotation process. Carbon-13 labeling studies showed that the {sup 13}C NMR carbonyl resonance increases with temperature for the encapsulated amides which suggests that the assembly is able to favor a twisted for of the amide.
Date: April 8, 2008
Creator: Pluth, Michael D.; Bergman, Robert G. & Raymond, Kenneth N.
System: The UNT Digital Library
Accelerator development for a radioactive beam facility based on ATLAS. (open access)

Accelerator development for a radioactive beam facility based on ATLAS.

The existing superconducting linac ATLAS is in many respects an ideal secondary beam accelerator for an ISOL (Isotope separator on-line) type radioactive beam facility. Such a facility would require the addition of two major accelerator elements: a low charge state injector for the existing heavy ion linac, and a primary beam accelerator providing 220 MV of acceleration for protons and light ions. Development work for both of these elements, including the option of superconducting cavities for the primary beam accelerator is discussed.
Date: January 8, 1998
Creator: Shepard, K. W.
System: The UNT Digital Library
Accurate Method for Determining Adhesion of Cantilever Beams (open access)

Accurate Method for Determining Adhesion of Cantilever Beams

Using surface micromachined samples, we demonstrate the accurate measurement of cantilever beam adhesion by using test structures which are adhered over long attachment lengths. We show that this configuration has a deep energy well, such that a fracture equilibrium is easily reached. When compared to the commonly used method of determining the shortest attached beam, the present method is much less sensitive to variations in surface topography or to details of capillary drying.
Date: January 8, 1999
Creator: Michalske, T. A. & De Boer, M. P.
System: The UNT Digital Library
The ACP (Advanced Computer Program) Branch bus and real-time applications of the ACP multiprocessor system (open access)

The ACP (Advanced Computer Program) Branch bus and real-time applications of the ACP multiprocessor system

The ACP Branchbus, a high speed differential bus for data movement in multiprocessing and data acquisition environments, is described. This bus was designed as the central bus in the ACP multiprocessing system. In its full implementation with 16 branches and a bus switch, it will handle data rates of 160 MByte/sec and allow reliable data transmission over inter rack distances. We also summarize applications of the ACP system in experimental data acquisition, triggering and monitoring, with special attention paid to FASTBUS environments.
Date: May 8, 1987
Creator: Hance, R.; Areti, H.; Atac, R.; Biel, J.; Cook, A.; Fischler, M. et al.
System: The UNT Digital Library
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
Active sensors for health monitoring of aging aerospace structures (open access)

Active sensors for health monitoring of aging aerospace structures

A project to develop non-intrusive active sensors that can be applied on existing aging aerospace structures for monitoring the onset and progress of structural damage (fatigue cracks and corrosion) is presented. The state of the art in active sensors structural health monitoring and damage detection is reviewed. Methods based on (a) elastic wave propagation and (b) electro-mechanical (NM) impedance technique are sighted and briefly discussed. The instrumentation of these specimens with piezoelectric active sensors is illustrated. The main detection strategies (E/M impedance for local area detection and wave propagation for wide area interrogation) are discussed. The signal processing and damage interpretation algorithms are tuned to the specific structural interrogation method used. In the high-frequency EIM impedance approach, pattern recognition methods are used to compare impedance signatures taken at various time intervals and to identify damage presence and progression from the change in these signatures. In the wave propagation approach, the acoustic-ultrasonic methods identifying additional reflection generated from the damage site and changes in transmission velocity and phase are used. Both approaches benefit from the use of artificial intelligence neural networks algorithms that can extract damage features based on a learning process. Design and fabrication of a set of structural specimens …
Date: March 8, 2000
Creator: Giurgiutiu, Victor; Redmond, James M.; Roach, Dennis P. & Rackow, Kirk A.
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