The QCD Phase Diagram: Large Nc, Quarkyonic Matter and the Triple Point (open access)

The QCD Phase Diagram: Large Nc, Quarkyonic Matter and the Triple Point

I discuss the phase diagram of QCD in the large N_c limit. Quarkyonic Matter is described. The properties of QCD matter as measured in the abundance of produced particles are shown to be consistent with this phase diagram. A possible triple point of Hadronic Mater, Deconfined Matter and Quarkyonic matter is shown to explain various behaviors of ratios of particles abundances seen in CERN fixed target experiments.
Date: January 31, 2010
Creator: McLerran, L.
System: The UNT Digital Library
Bridging silyl groups in sigma-bond metathesis and [1, 2] shifts. An experimental and computational study of the reaction between cerium metallocenes and MeOSiMe3 (open access)

Bridging silyl groups in sigma-bond metathesis and [1, 2] shifts. An experimental and computational study of the reaction between cerium metallocenes and MeOSiMe3

The reaction of Cp'2CeH (Cp' = 1,2,4-(Me3C)3C5H2 ) with MeOSiMe3 gives Cp'2CeOMe and HSiMe3 and the reaction of the metallacycle, Cp'[(Me3C)2C5H2C(Me) 2CH2]Ce, with MeOSiMe3 yields Cp'2CeOCH2SiMe3, formed from hypothetical Cp'2CeCH2OSiMe3 by a [1, 2] shift also known as a silyl-Wittig rearrangement. Although both cerium products are alkoxides, they are formed by different pathways. DFT calculations on the reaction of the model metallocene, Cp2CeH, and MeOSiMe3 show that the lowest energy pathway is a H for OMe exchange at Ce that occurs by way of a sigma-bond metathesis transition state as SiMe3 exchanges partners. The formation of Cp2CeOCH2SiMe3 occurs by way of a low activation barrier [1, 2]shift of the SiMe3 group in Cp2CeCH2OSiMe3. Calculations on a model metallacycle, Cp[C5H4C(Me)2CH2]Ce, show that the metallacycle favors CH bond activation over sigma-bond metathesis involving the transfer of the SiMe3 group in good agreement with experiment. The sigma-bond metathesis involving the transfer of SiMe3 and the [1, 2]shift of SiMe3 reactions have in common a pentacoordinate silicon at the transition states. A molecular orbital analysis illustrates the connection between these two Si-O bond cleavage reactions and traces the reason why they occur for a silyl but not for an alkyl group to the difference …
Date: April 21, 2010
Creator: Werkema, Evan; Yahia, Ahmed; Maron, Laurent; Eisenstein, Odile & Andersen, Richard
System: The UNT Digital Library
The Role of Quench-back in the Passive Quench Protection of Uncoupled Solenoids in Series with and without Coil Sub-division (open access)

The Role of Quench-back in the Passive Quench Protection of Uncoupled Solenoids in Series with and without Coil Sub-division

This paper is the final paper in a series of papers that discusses passive quench protection for high inductance solenoid magnets. This report describes how passive quench protection system may be applied to superconducting magnets that are connected in series but not inductively coupled. Previous papers have discussed the role of magnet sub-division and quench back from a conductive mandrel in reducing the hot-spot temperature and the peak coil voltages to ground. When magnets are connected in series, quench-back from a conductive mandrel can cause other magnets in a string to quench even without inductive coupling between magnets. The magnet mandrels must be well coupled to the magnet circuit that is being quenched. When magnet circuit sub-division is employed to reduce the voltages-to-ground within magnets, the resistance across the subdivision becomes the most important factor in the successful quenching of the magnet string.
Date: October 15, 2010
Creator: Guo, Xing Long; Green, Michael A; Wang, Li; Wu, Hong & Pan, Heng
System: The UNT Digital Library
Personal Dose Equivalent Conversion Coefficients For Photons To 1 GEV (open access)

Personal Dose Equivalent Conversion Coefficients For Photons To 1 GEV

The personal dose equivalent, H{sub p}(d), is the quantity recommended by the International Commission on Radiation Units and Measurements (ICRU) to be used as an approximation of the protection quantity Effective Dose when performing personal dosemeter calibrations. The personal dose equivalent can be defined for any location and depth within the body. Typically, the location of interest is the trunk where personal dosemeters are usually worn and in this instance a suitable approximation is a 30 cm X 30 cm X 15 cm slab-type phantom. For this condition the personal dose equivalent is denoted as H{sub p,slab}(d) and the depths, d, are taken to be 0.007 cm for non-penetrating and 1 cm for penetrating radiation. In operational radiation protection a third depth, 0.3 cm, is used to approximate the dose to the lens of the eye. A number of conversion coefficients for photons are available for incident energies up to several MeV, however, data to higher energies are limited. In this work conversion coefficients up to 1 GeV have been calculated for H{sub p,slab}(10) and H{sub p,slab}(3) using both the kerma approximation and by tracking secondary charged particles. For H{sub p}(0.07) the conversion coefficients were calculated, but only to 10 …
Date: September 27, 2010
Creator: Veinot, K. G. & Hertel, N. E.
System: The UNT Digital Library
Results of applying a non-evaporative mitigation technique to laser-initiated surface damage on fused-silica (open access)

Results of applying a non-evaporative mitigation technique to laser-initiated surface damage on fused-silica

We present results from a study to determine an acceptable CO{sub 2} laser-based non-evaporative mitigation protocol for use on surface damage sites in fused-silica optics. A promising protocol is identified and evaluated on a set of surface damage sites created under ICF-type laser conditions. Mitigation protocol acceptability criteria for damage re-initiation and growth, downstream intensification, and residual stress are discussed. In previous work, we found that a power ramp at the end of the protocol effectively minimizes the residual stress (<25 MPa) left in the substrate. However, the biggest difficulty in determining an acceptable protocol was balancing between low re-initiation and problematic downstream intensification. Typical growing surface damage sites mitigated with a candidate CO{sub 2} laser-based mitigation protocol all survived 351 nm, 5 ns damage testing to fluences >12.5 J/cm{sup 2}. The downstream intensification arising from the mitigated sites is evaluated, and all but one of the sites has 100% passing downstream damage expectation values. We demonstrate, for the first time, a successful non-evaporative 10.6 {micro}m CO{sub 2} laser mitigation protocol applicable to fused-silica optics used on fusion-class lasers like the National Ignition Facility (NIF).
Date: October 26, 2010
Creator: Adams, J. J.; Bolourchi, M.; Bude, J. D.; Guss, G. M.; Matthews, M. J. & Nostrand, M. C.
System: The UNT Digital Library
Experimental Study of High-Z Gas Buffers in Gas-Filled ICF Engines (open access)

Experimental Study of High-Z Gas Buffers in Gas-Filled ICF Engines

ICF power plants, such as the LIFE scheme at LLNL, may employ a high-Z, target-chamber gas-fill to moderate the first-wall heat-pulse due to x-rays and energetic ions released during target detonation. To reduce the uncertainties of cooling and beam/target propagation through such gas-filled chambers, we present a pulsed plasma source producing 2-5 eV plasma comprised of high-Z gases. We use a 5-kJ, 100-ns theta discharge for high peak plasma-heating-power, an electrode-less discharge for minimizing impurities, and unobstructed axial access for diagnostics and beam (and/or target) propagation studies. We will report on the plasma source requirements, design process, and the system design.
Date: December 3, 2010
Creator: Rhodes, M A; Kane, J; Loosmore, G; DeMuth, J & Latkowski, J
System: The UNT Digital Library
Determination of the spin-flip time in ferromagnetic SrRuO3 from time-resolved Kerr measurements (open access)

Determination of the spin-flip time in ferromagnetic SrRuO3 from time-resolved Kerr measurements

We report time-resolved Kerr effect measurements of magnetization dynamics in ferromagnetic SrRuO{sub 3}. We observe that the demagnetization time slows substantially at temperatures within 15K of the Curie temperature, which is {approx} 150K. We analyze the data with a phenomenological model that relates the demagnetization time to the spin flip time. In agreement with our observations the model yields a demagnetization time that is inversely proportional to T-T{sub c}. We also make a direct comparison of the spin flip rate and the Gilbert damping coefficient showing that their ratio very close to k{sub B}T{sub c}, indicating a common origin for these phenomena.
Date: July 30, 2010
Creator: Kantner, C. L. S.; Langner, M. C.; Siemons, W.; Blok, J. L.; Koster, G.; Rijnders, A.J. H. M. et al.
System: The UNT Digital Library
Subduction Controls of Hf and Nd Isotopes in Lavas of the Aleutian Island Arc (open access)

Subduction Controls of Hf and Nd Isotopes in Lavas of the Aleutian Island Arc

The Hf and Nd isotopic compositions of 71 Quaternary lavas collected from locations along the full length of the Aleutian island arc are used to constrain the sources of Aleutian magmas and to provide insight into the geochemical behavior of Nd and Hf and related elements in the Aleutian subduction-magmatic system. Isotopic compositions of Aleutian lavas fall approximately at the center of, and form a trend parallel to, the terrestrial Hf-Nd isotopic array with {var_epsilon}{sub Hf} of +12.0 to +15.5 and {var_epsilon}{sub Nd} of +6.5 to +10.5. Basalts, andesites, and dacites within volcanic centers or in nearby volcanoes generally all have similar isotopic compositions, indicating that there is little measurable effect of crustal or other lithospheric assimilation within the volcanic plumbing systems of Aleutian volcanoes. Hafnium isotopic compositions have a clear pattern of along-arc increase that is continuous from the eastern-most locations near Cold Bay to Piip Seamount in the western-most part of the arc. This pattern is interpreted to reflect a westward decrease in the subducted sediment component present in Aleutian lavas, reflecting progressively lower rates of subduction westward as well as decreasing availability of trench sediment. Binary bulk mixing models (sediment + peridotite) demonstrate that 1-2% of the …
Date: August 29, 2010
Creator: Yogodzinski, Gene; Vervoort, Jeffery; Brown, Shaun Tyler & Gerseny, Megan
System: The UNT Digital Library
Structural and Morphological Properties of Carbon Supports: Effect on Catalyst Degradation (open access)

Structural and Morphological Properties of Carbon Supports: Effect on Catalyst Degradation

The object of this work was to identify correlations between performance losses of Pt electrocatalysts on carbon support materials and the chemical and morphological parameters that describe them. Accelerated stress testing, with an upper potential of 1.2 V, was used to monitor changes to cathode properties, including kinetic performance and effective platinum surface area losses. The structure and chemical compositions were studied using X-ray Photoelectron Spectroscopy and Scanning Electron Microscopy coupled with Digital Image Processing. As this is an ongoing study, it is difficult to draw firm conclusions, though a trend between support surface area overall performance loss was found to exist.
Date: July 1, 2010
Creator: Patel, Anant; Artyushkova, Kateryna; Atanassov, Plamen; Young, Alan; Dutta, Monica; Ahmad, Zaid et al.
System: The UNT Digital Library
Quantum efficiency temporal response and lifetime of a GaAs cathode in SRF electron gun (open access)

Quantum efficiency temporal response and lifetime of a GaAs cathode in SRF electron gun

RF electron guns with a strained super lattice GaAs cathode can generate polarized electron beam of higher brightness and lower emittance than do DC guns, due to their higher field gradient at the cathode's surface. In a normal conducting RF gun, the extremely high vaccum required by these cathodes can not be met. We report on an experiment with a superconducting SRF gun, which can maintain a vacuum of nearly 10-12 torr because of cryo-pumping at the temperature of 4.2K. With conventional activation, we obtained a QE of 3% at 532 nm, with lifetime of nearly 3 days in the preparation chamber. We plan to use this cathode in a 1.3 GHz 1/2 cell SRF gun to study its performance. In addition, we studied the multipacting at the location of cathode. A new model based on the Forkker-Planck equation which can estimate the bunch length of the electron beam is discussed in this paper. Future particle accelerators such as eRHIC and ILC require high brightness, high current polarized electrons Recently, using a superlattice crystal, the maximum polarization of 95% was reached. Activation with Cs,O lowers the electron affinity and makes it energetically possible for all the electrons excited in to …
Date: May 23, 2010
Creator: Wang, E.; Ben-Zvi, Ilan; Kewisch, J.; Burrill, A.; Rao, T.; Wu, Q. et al.
System: The UNT Digital Library
Modeling of fate and transport of co-injection of H2S with CO2 in deep saline formations (open access)

Modeling of fate and transport of co-injection of H2S with CO2 in deep saline formations

The geological storage of CO{sub 2} in deep saline formations is increasing seen as a viable strategy to reduce the release of greenhouse gases into the atmosphere. However, costs of capture and compression of CO{sub 2} from industrial waste streams containing small quantities of sulfur and nitrogen compounds such as SO{sub 2}, H{sub 2}S and N{sub 2} are very expensive. Therefore, studies on the co-injection of CO{sub 2} containing other acid gases from industrial emissions are very important. In this paper, numerical simulations were performed to study the co-injection of H{sub 2}S with CO{sub 2} in sandstone and carbonate formations. Results indicate that the preferential dissolution of H{sub 2}S gas (compared with CO{sub 2} gas) into formation water results in the delayed breakthrough of H{sub 2}S gas. Co-injection of H{sub 2}S results in the precipitation of pyrite through interactions between the dissolved H{sub 2}S and Fe{sup 2+} from the dissolution of Fe-bearing minerals. Additional injection of H{sub 2}S reduces the capabilities for solubility and mineral trappings of CO{sub 2} compared to the CO{sub 2} only case. In comparison to the sandstone (siliciclastic) formation, the carbonate formation is less favorable to the mineral sequestration of CO{sub 2}. Different from CO{sub 2} …
Date: December 15, 2010
Creator: Zhang, W.; Xu, T. & Li, Y.
System: The UNT Digital Library
Studies of non-proportionality in alkali halide and strontium iodide scintillators using SLYNCI (open access)

Studies of non-proportionality in alkali halide and strontium iodide scintillators using SLYNCI

Recently a collaboration of LLNL and LBNL has constructed a second generation Compton coincidence instrument to study the non-proportionality of scintillators. This device, known as SLYNCI (Scintillator Light-Yield Non-proportionality Characterization Instrument), has can completely characterize a sample with less than 24 hours of running time. Thus, SLYNCI enables a number of systematic studies of scintillators since many samples can be processed in a reasonable length of time. These studies include differences in nonproportionality between different types of scintillators, different members of the same family of scintillators, and impact of different doping levels. The results of such recent studies are presented here, including a study of various alkali halides, and the impact of europium doping level in strontium iodide. Directions of future work area also discussed.
Date: October 14, 2010
Creator: Ahle, Larry; Bizarri, Gregory; Boatner, Lynn; Cherepy, Nerine J.; Choong, Woon-Seng; Moses, William W. et al.
System: The UNT Digital Library
EFFECT OF GLASS-BATCH MAKEUP ON THE MELTING PROCESS (open access)

EFFECT OF GLASS-BATCH MAKEUP ON THE MELTING PROCESS

The response of a glass batch to heating is determined by the batch makeup and in turn determines the rate of melting. Batches formulated for a high-alumina nuclear waste to be vitrified in an all-electric melter were heated at a constant temperature-increase rate to determine changes in melting behavior in response to the selection of batch chemicals and silica grain-size as well as the addition of heat-generating reactants. The type of batch materials and the size of silica grains determine how much, if any, primary foam occurs during melting. Small quartz grains, 5 {micro}m in size, caused extensive foaming because their major portion dissolved at temperatures <800 C, contributing to the formation of viscous glass forming melt that trapped evolving batch gases. Primary foam did not occur in batches with larger quartz grains, {+-}75 {micro}m in size, because their major portion dissolved at temperatures >800 C when batch gases no longer evolved. The exothermal reaction of nitrates with sucrose was ignited at a temperature as low as 160 C and caused a temporary jump in temperature of several hundred degrees. Secondary foam, the source of which is oxygen from redox reactions, occurred in all batches of a limited composition variation …
Date: December 7, 2010
Creator: AA, KRUGER & P, HRMA
System: The UNT Digital Library
Task 1—Steam Oxidation (NETL-US) (open access)

Task 1—Steam Oxidation (NETL-US)

The proposed steam in let temperature in the Advanced Ultra Supercritical (A·USC) steam turbine is high enough (760°C) Ihat traditional turbine casing and valve body materials such as ferr;tic/manensitic steels will not suffice due to temperature lim itations of this class of materials. Cast versions of three traditionally wrought Ni-based superalloys (Haynes 263. Haynes 282, and Nimonic 105) were evaluated for use as casing or valve components for the next generation of industrial steam turbines. The full size castings are substantia l: 2-5,000 kg each half and on the order of 100 nun thick. Experimental castings were quite a bit smaller, but section size was retained and cooling rate controlled to produce equi valem microslruclUre •. A multi_step homogenization heat treatment was d~ve loped to better disperse the al loy constituents. These castings were subsequently evaluated by characterizing their microstructure as well as their steam oxidation resistance (al 760 and 800 "C).
Date: May 1, 2010
Creator: Holcomb, G. R.
System: The UNT Digital Library
Transport and deposition of functionalized CdTe nanoparticles in saturated porous media (open access)

Transport and deposition of functionalized CdTe nanoparticles in saturated porous media

Comprehensive understanding of the transport and deposition of engineered nanoparticles (NPs) in subsurface is required to assess their potential negative impact on the environment. We studied the deposition behavior of functionalized quantum dot (QD) NPs (CdTe) in different types of sands (Accusand, ultrapure quartz, and iron-coated sand) at various solution ionic strengths (IS). The observed transport behavior in ultrapure quartz and iron-coated sand was consistent with conventional colloid deposition theories. However, our results from the Accusand column showed that deposition was minimal at the lowest IS (1 mM) and increased significantly as the IS increased. The effluent breakthrough occurred with a delay, followed by a rapid rise to the maximum normalized concentration of unity. Negligible deposition in the column packed with ultrapure quartz sand (100 mM) and Accusand (1 mM) rules out the effect of straining and suggests the importance of surface charge heterogeneity in QD deposition in Accusand at higher IS. Data analyses further show that only a small fraction of sand surface area contributed in QD deposition even at the highest IS (100 mM) tested. The observed delay in breakthrough curves of QDs was attributed to the fast diffusive mass transfer rate of QDs from bulk solution to …
Date: October 15, 2010
Creator: Torkzaban, S.; Wan, J.; Kim, Y.; Mulvihill, M. & Tokunaga, T. K.
System: The UNT Digital Library
Superresolution with Seismic Arrays using Empirical Matched Field Processing (open access)

Superresolution with Seismic Arrays using Empirical Matched Field Processing

Scattering and refraction of seismic waves can be exploited with empirical matched field processing of array observations to distinguish sources separated by much less than the classical resolution limit. To describe this effect, we use the term 'superresolution', a term widely used in the optics and signal processing literature to denote systems that break the diffraction limit. We illustrate superresolution with Pn signals recorded by the ARCES array in northern Norway, using them to identify the origins with 98.2% accuracy of 549 explosions conducted by closely-spaced mines in northwest Russia. The mines are observed at 340-410 kilometers range and are separated by as little as 3 kilometers. When viewed from ARCES many are separated by just tenths of a degree in azimuth. This classification performance results from an adaptation to transient seismic signals of techniques developed in underwater acoustics for localization of continuous sound sources. Matched field processing is a potential competitor to frequency-wavenumber and waveform correlation methods currently used for event detection, classification and location. It operates by capturing the spatial structure of wavefields incident from a particular source in a series of narrow frequency bands. In the rich seismic scattering environment, closely-spaced sources far from the observing array …
Date: March 24, 2010
Creator: Harris, D B & Kvaerna, T
System: The UNT Digital Library
Low-frequency fluid waves in fractures and pipes (open access)

Low-frequency fluid waves in fractures and pipes

Low-frequency analytical solutions have been obtained for phase velocities of symmetrical fluid waves within both an infinite fracture and a pipe filled with a viscous fluid. Three different fluid wave regimes can exist in such objects, depending on the various combinations of parameters, such as fluid density, fluid viscosity, walls shear modulus, channel thickness, and frequency. Equations for velocities of all these regimes have explicit forms and are verified by comparisons with the exact solutions. The dominant role of fractures in rock permeability at field scales and the strong amplitude and frequency effects of Stoneley guided waves suggest the importance of including these wave effects into poroelastic theories.
Date: September 1, 2010
Creator: Korneev, Valeri
System: The UNT Digital Library
A three wavelength scheme to optimize hohlraum coupling on the National Ignition Facility (open access)

A three wavelength scheme to optimize hohlraum coupling on the National Ignition Facility

By using three tunable wavelengths on different cones of laser beams on the National Ignition Facility, numerical simulations show that the energy transfer between beams can be tuned to redistribute the energy within the cones of beams most prone to backscatter instabilities. These radiative hydrodynamics and laser-plasma interaction simulations have been tested against large scale hohlraum experiments with two tunable wavelengths, and reproduce the hohlraum energetics and symmetry. Using a third wavelength provides a greater level of control of the laser energy distribution and coupling in the hohlraum, and could significantly reduce stimulated Raman scattering losses and increase the hohlraum radiation drive while maintaining a good implosion symmetry.
Date: December 16, 2010
Creator: Michel, P; Divol, L; Town, R & Rosen, M
System: The UNT Digital Library
Numerical simulation studies of the long-term evolution of a CO2 plume in a saline aquifer with a sloping caprock (open access)

Numerical simulation studies of the long-term evolution of a CO2 plume in a saline aquifer with a sloping caprock

We have used the TOUGH2-MP/ECO2N code to perform numerical simulation studies of the long-term behavior of CO{sub 2} stored in an aquifer with a sloping caprock. This problem is of great practical interest, and is very challenging due to the importance of multi-scale processes. We find that the mechanism of plume advance is different from what is seen in a forced immiscible displacement, such as gas injection into a water-saturated medium. Instead of pushing the water forward, the plume advances because the vertical pressure gradients within the plume are smaller than hydrostatic, causing the groundwater column to collapse ahead of the plume tip. Increased resistance to vertical flow of aqueous phase in anisotropic media leads to reduced speed of updip plume advancement. Vertical equilibrium models that ignore effects of vertical flow will overpredict the speed of plume advancement. The CO{sub 2} plume becomes thinner as it advances, yet the speed of advancement remains constant over the entire simulation period of up to 400 years, with migration distances of more than 80 km. Our simulations include dissolution of CO{sub 2} into the aqueous phase and associated density increase, and molecular diffusion. However, no convection develops in the aqueous phase because it …
Date: December 28, 2010
Creator: Pruess, K. & Nordbotten, J.
System: The UNT Digital Library
"Applications and future trends in polymer materials for green energy systems: from energy generation and storage, to CO2 capture and transportaion" (open access)

"Applications and future trends in polymer materials for green energy systems: from energy generation and storage, to CO2 capture and transportaion"

Presentation describes United Technologies Research Center's recent work in green energy systems, including APRA-E project content to create a synthetic analogue of the carbonic anhydrase enzyme and incorporate it into a membrane for CO2 separation from the flue gas of a coal power plant.
Date: August 24, 2010
Creator: Zafiris, George
System: The UNT Digital Library
Predicting Image Blur in Proton Radiography: Comparisons Between Measurements and Monte Carlo Simulations (open access)

Predicting Image Blur in Proton Radiography: Comparisons Between Measurements and Monte Carlo Simulations

Given the cost and lead-times involved in high-energy proton radiography, it is prudent to model proposed radiographic experiments to see if the images predicted would return useful information. We recently modified our raytracing transmission radiography modeling code HADES to perform simplified Monte Carlo simulations of the transport of protons in a proton radiography beamline. Beamline objects include the initial diffuser, vacuum magnetic fields, windows, angle-selecting collimators, and objects described as distorted 2D (planar or cylindrical) meshes or as distorted 3D hexahedral meshes. We present an overview of the algorithms used for the modeling and code timings for simulations through typical 2D and 3D meshes. We next calculate expected changes in image blur as scattering materials are placed upstream and downstream of a resolution test object (a 3 mm thick sheet of tantalum, into which 0.4 mm wide slits have been cut), and as the current supplied to the focusing magnets is varied. We compare and contrast the resulting simulations with the results of measurements obtained at the 800 MeV Los Alamos LANSCE Line-C proton radiography facility.
Date: May 7, 2010
Creator: Schach von Wittenau, Alexis E.; Aufderheide, Maurice B., III & Henderson, Gary L.
System: The UNT Digital Library
Holey Silicon as an Efficient Thermoelectric Material (open access)

Holey Silicon as an Efficient Thermoelectric Material

This work investigated the thermoelectric properties of thin silicon membranes that have been decorated with high density of nanoscopic holes. These ?holey silicon? (HS) structures were fabricated by either nanosphere or block-copolymer lithography, both of which are scalable for practical device application. By reducing the pitch of the hexagonal holey pattern down to 55 nm with 35percent porosity, the thermal conductivity of HS is consistently reduced by 2 orders of magnitude and approaches the amorphous limit. With a ZT value of 0.4 at room temperature, the thermoelectric performance of HS is comparable with the best value recorded in silicon nanowire system.
Date: September 30, 2010
Creator: Tang, Jinyao; Wang, Hung-Ta; Hyun Lee, Dong; Fardy, Melissa; Huo, Ziyang; Russell, Thomas P. et al.
System: The UNT Digital Library
Performance of Integrated Systems of Automated Roller Shade Systems and Daylight Responsive Dimming Systems (open access)

Performance of Integrated Systems of Automated Roller Shade Systems and Daylight Responsive Dimming Systems

Daylight responsive dimming systems have been used in few buildings to date because they require improvements to improve reliability. The key underlying factor contributing to poor performance is the variability of the ratio of the photosensor signal to daylight workplane illuminance in accordance with sun position, sky condition, and fenestration condition. Therefore, this paper describes the integrated systems between automated roller shade systems and daylight responsive dimming systems with an improved closed-loop proportional control algorithm, and the relative performance of the integrated systems and single systems. The concept of the improved closed-loop proportional control algorithm for the integrated systems is to predict the varying correlation of photosensor signal to daylight workplane illuminance according to roller shade height and sky conditions for improvement of the system accuracy. In this study, the performance of the integrated systems with two improved closed-loop proportional control algorithms was compared with that of the current (modified) closed-loop proportional control algorithm. In the results, the average maintenance percentage and the average discrepancies of the target illuminance, as well as the average time under 90percent of target illuminance for the integrated systems significantly improved in comparison with the current closed-loop proportional control algorithm for daylight responsive dimming systems …
Date: July 8, 2010
Creator: Park, Byoung-Chul; Choi, An-Seop; Jeong, Jae-Weon & Lee, Eleanor S.
System: The UNT Digital Library
Pediatric Healthcare Response to Pandemic (H1N1) 2009 Influenza Stakeholder Meeting - Summary of Proceedings (open access)

Pediatric Healthcare Response to Pandemic (H1N1) 2009 Influenza Stakeholder Meeting - Summary of Proceedings

The goal of the meeting was to bring together subject matter experts to develop tools and resources for use by the pediatric healthcare community in response to 2009 (H1N1) pandemic influenza activity during the 2009 influenza season.
Date: January 1, 2010
Creator: CHE, HCTT
System: The UNT Digital Library