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Fully Integrated Applications of Thin Films on Low Temperature Cofired Ceramic (LTCC) (open access)

Fully Integrated Applications of Thin Films on Low Temperature Cofired Ceramic (LTCC)

Thin film multilayers have previously been introduced on multilayer low temperature cofired ceramic (LTCC), as well as initial thin film capacitors on LTCC. The ruggedness of a multipurpose Ti-Cu-Pt-Au stack for connectivity and RF conductivity has continued to benefit fabrication and reliability in state of-the-art modules, while the capacitors have followed the traditional Metal-Insulator-Metal (MIM) style. The full integration of thin film passives with thin film connectivity traces is presented. Certain passives, such as capacitors, require specifically tailored and separately patterned thin film (multi-)layers, including a dielectric. Different capacitance values are achieved by variation of both the insulator layer thickness and the active area of the capacitor. Other passives, such as filters, require only the conductor - a single thin film multilayer. This can be patterned from the same connectivity thin film material (Ti-Cu-Pt-Au), or a specially tailored thin film material (e.g. Ti-Cu-Au) can be deposited. Both versions are described, including process and integration details. Examples are discussed, ranging from patterning for maximum tolerances, to space and performance-optimized designs. Cross-sectional issues associated with integration are also highlighted in the discussion.
Date: April 19, 2012
Creator: Wolf, Ambrose; Peterson, Ken; O'Keefe, Matt; Huebner, Wayne & Kuhn, Bill
System: The UNT Digital Library
Observation of Shot Noise Suppression at Optical Wavelengths in a Relativistic Electron Beam (open access)

Observation of Shot Noise Suppression at Optical Wavelengths in a Relativistic Electron Beam

Control of collective properties of relativistic particles is increasingly important in modern accelerators. In particular, shot noise affects accelerator performance by driving instabilities or by competing with coherent processes. We present experimental observations of shot noise suppression in a relativistic beam at the Linac Coherent Light Source. By adjusting the dispersive strength of a chicane, we observe a decrease in the optical transition radiation emitted from a downstream foil. We show agreement between the experimental results, theoretical models, and 3D particle simulations.
Date: June 19, 2012
Creator: Ratner, Daniel & Stupakov, Gennady
System: The UNT Digital Library
IRON-PHOSPHATE GLASS FOR IMMOBILIZATION OF RADIOACTIVE TECHNETIUM (open access)

IRON-PHOSPHATE GLASS FOR IMMOBILIZATION OF RADIOACTIVE TECHNETIUM

Technetium-99 (Tc-99) can bring a serious environmental threat because of its high fission yield, long half-life, and high solubility and mobility in the ground water. The present work investigated the immobilization of Tc-99 (surrogated by Re) by heat-treating mixtures of an iron-phosphate glass with 1.5 to 6 wt.% KReO{sub 4} at {approx}1000 C. The Re retention in the glass was as high as {approx}1.2 wt. % while the loss of Re by evaporation during melting was {approx}50%. Re was uniformly distributed within the glass. The normalized Re release by the 7-day Product Consistency Test was {approx}0.39 g/m{sup 2}, comparable with that in phosphate-bonded ceramics and borosilicate glasses. These results suggest that iron-phosphate glass can provide a good matrix for immobilizing Tc-99.
Date: March 19, 2012
Creator: AA, KRUGER; PR, HRMA; K, XU; J, CHOI; W, UM & J, HEO
System: The UNT Digital Library
SILICA GEL BEHAVIOR UNDER DIFFERENT EGS CHEMICAL AND THERMAL CONDITIONS: AN EXPERIMENTAL STUDY (open access)

SILICA GEL BEHAVIOR UNDER DIFFERENT EGS CHEMICAL AND THERMAL CONDITIONS: AN EXPERIMENTAL STUDY

Fractures and fracture networks are the principal pathways for migration of water and contaminants in groundwater systems, fluids in enhanced geothermal systems (EGS), oil and gas in petroleum reservoirs, carbon dioxide leakage from geological carbon sequestration, and radioactive and toxic industrial wastes from underground storage repositories. When dealing with EGS fracture networks, there are several major issues to consider, e.g., the minimization of hydraulic short circuits and losses of injected geothermal fluid to the surrounding formation, which in turn maximize heat extraction and economic production. Gel deployments to direct and control fluid flow have been extensively and successfully used in the oil industry for enhanced oil recovery. However, to the best of our knowledge, gels have not been applied to EGS to enhance heat extraction. In-situ gelling systems can either be organic or inorganic. Organic polymer gels are generally not thermostable to the typical temperatures of EGS systems. Inorganic gels, such as colloidal silica gels, however, may be ideal blocking agents for EGS systems if suitable gelation times can be achieved. In the current study, we explore colloidal silica gelation times and rheology as a function of SiO{sub 2} concentration, pH, salt concentration, and temperature, with preliminary results in the …
Date: January 19, 2012
Creator: Hunt, J D; Ezzedine, S M; Bourcier, W & Roberts, S
System: The UNT Digital Library
A Critical Appraisal of NLO+PS Matching Methods (open access)

A Critical Appraisal of NLO+PS Matching Methods

In this publication, uncertainties in and differences between the MC{at}NLO and POWHEG methods for matching next-to-leading order QCD calculations with parton showers are discussed. Implementations of both algorithms within the event generator SHERPA are employed to assess the impact on a representative selection of observables. In the MC{at}NLO approach a phase space restriction has been added to subtraction and parton shower, which allows to vary in a transparent way the amount of non-singular radiative corrections that are exponentiated. Effects on various observables are investigated, using the production of a Higgs boson in gluon fusion, with or without an associated jet, as a benchmark process. The case of H+jet production is presented for the first time in an NLO+PS matched simulation. Uncertainties due to scale choices and non-perturbative effects are explored in the production of W{sup {+-}} and Z bosons in association with a jet. Corresponding results are compared to data from the Tevatron and LHC experiments.
Date: March 19, 2012
Creator: Hoeche, Stefan; Krauss, Frank; Schonherr, Marek & Siegert, Frank
System: The UNT Digital Library
Grain-Scale Failure in Thermal Spallation Drilling (open access)

Grain-Scale Failure in Thermal Spallation Drilling

Geothermal power promises clean, renewable, reliable and potentially widely-available energy, but is limited by high initial capital costs. New drilling technologies are required to make geothermal power financially competitive with other energy sources. One potential solution is offered by Thermal Spallation Drilling (TSD) - a novel drilling technique in which small particles (spalls) are released from the rock surface by rapid heating. While TSD has the potential to improve drilling rates of brittle granitic rocks, the coupled thermomechanical processes involved in TSD are poorly described, making system control and optimization difficult for this drilling technology. In this paper, we discuss results from a new modeling effort investigating thermal spallation drilling. In particular, we describe an explicit model that simulates the grain-scale mechanics of thermal spallation and use this model to examine existing theories concerning spalling mechanisms. We will report how borehole conditions influence spall production, and discuss implications for macro-scale models of drilling systems.
Date: January 19, 2012
Creator: Walsh, Stuart C.; Lomov, Ilya & Roberts, Jeffery J.
System: The UNT Digital Library
Search for Bbar to Lambda_c+ X l- nu Decays in Events with a Fully Reconstructed B Meson (open access)

Search for Bbar to Lambda_c+ X l- nu Decays in Events with a Fully Reconstructed B Meson

We present a search for semileptonic B decays to the charmed baryon {Lambda}{sub c}{sup +} based on 420 fb{sup -1} of data collected at the {Upsilon}(4S) resonance with the BABAR detector at the PEP-II e{sup +}e{sup -} storage rings. By fully reconstructing the recoiling B in a hadronic decay mode, we reduce non-B backgrounds and determine the flavor of the signal B. We statistically correct the flavor for the effect of the B{sup 0} mixing. We obtain a 90% confidence level upper limit of {Beta}({bar B} {yields} {Lambda}{sub c}{sup +} X{ell}{sup -} {bar {nu}}{sub {ell}})/{Beta}({bar B} {yields} {Lambda}{sub c}{sup +} X) < 3.5%.
Date: April 19, 2012
Creator: Lees, J. P.; Poireau, V.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M. et al.
System: The UNT Digital Library
Fiber Lasers X: Technology, Systems and Aplications (open access)

Fiber Lasers X: Technology, Systems and Aplications

None
Date: July 19, 2012
Creator: Drachenberg, D
System: The UNT Digital Library
Techniques for correcting velocity and density fluctuations of ion beams (open access)

Techniques for correcting velocity and density fluctuations of ion beams

None
Date: June 19, 2012
Creator: Woo, K. M.; Yu, S. S. & Barnard, J. J.
System: The UNT Digital Library
The Cornell-SLAC Pixel Array Detector at LCLS (open access)

The Cornell-SLAC Pixel Array Detector at LCLS

None
Date: November 19, 2012
Creator: Hart, P.; Boutet, S.; Carini, G.; Dragone, A.; Duda, B.; Freytag, D. et al.
System: The UNT Digital Library
Modeling Ion-Exchange Processing With Spherical Resins For Cesium Removal (open access)

Modeling Ion-Exchange Processing With Spherical Resins For Cesium Removal

The spherical Resorcinol-Formaldehyde and hypothetical spherical SuperLig(r) 644 ion-exchange resins are evaluated for cesium removal from radioactive waste solutions. Modeling results show that spherical SuperLig(r) 644 reduces column cycling by 50% for high-potassium solutions. Spherical Resorcinol Formaldehyde performs equally well for the lowest-potassium wastes. Less cycling reduces nitric acid usage during resin elution and sodium addition during resin regeneration, therefore, significantly decreasing life-cycle operational costs. A model assessment of the mechanism behind ''cesium bleed'' is also conducted. When a resin bed is eluted, a relatively small amount of cesium remains within resin particles. Cesium can bleed into otherwise decontaminated product in the next loading cycle. The bleed mechanism is shown to be fully isotherm-controlled vs. mass transfer controlled. Knowledge of residual post-elution cesium level and resin isotherm can be utilized to predict rate of cesium bleed in a mostly non-loaded column. Overall, this work demonstrates the versatility of the ion-exchange modeling to study the effects of resin characteristics on processing cycles, rates, and cold chemical consumption. This evaluation justifies further development of a spherical form of the SL644 resin.
Date: September 19, 2012
Creator: Hang, T.; Nash, C. A. & Aleman, S. E.
System: The UNT Digital Library
Theory and Gyro-fluid Simulations of Edge-Localized-Modes (open access)

Theory and Gyro-fluid Simulations of Edge-Localized-Modes

None
Date: September 19, 2012
Creator: Xu, X Q
System: The UNT Digital Library
Moisture desorption rates from TATB-formulations: experiments and kinetic models (open access)

Moisture desorption rates from TATB-formulations: experiments and kinetic models

None
Date: January 19, 2012
Creator: Glascoe, E. A.; Dinh, L. N.; Small, W. & Overturf, G. E.
System: The UNT Digital Library
Task 2—Materials for Advanced Boiler and Oxy-combustion Systems (NETL-US) (open access)

Task 2—Materials for Advanced Boiler and Oxy-combustion Systems (NETL-US)

None
Date: April 19, 2012
Creator: Holcomb, Gordon R. & Tylczak, Joseph
System: The UNT Digital Library
Task 1—Steam Oxidation (NETL-US) (open access)

Task 1—Steam Oxidation (NETL-US)

None
Date: April 19, 2012
Creator: Holcomb, Gordon R. & Tylczak, Joseph
System: The UNT Digital Library
Thermal annealing of laser damage precursors on fused silica surfaces (open access)

Thermal annealing of laser damage precursors on fused silica surfaces

Previous studies have identified two significant precursors of laser damage on fused silica surfaces at fluenes below {approx} 35 J/cm{sup 2}, photoactive impurities in the polishing layer and surface fractures. In the present work, isothermal heating is studied as a means of remediating the highly absorptive, defect structure associated with surface fractures. A series of Vickers indentations were applied to silica surfaces at loads between 0.5N and 10N creating fracture networks between {approx} 10{micro}m and {approx} 50{micro}m in diameter. The indentations were characterized prior to and following thermal annealing under various times and temperature conditions using confocal time-resolved photo-luminescence (CTP) imaging, and R/1 optical damage testing with 3ns, 355nm laser pulses. Significant improvements in the damage thresholds, together with corresponding reductions in CTP intensity, were observed at temperatures well below the glass transition temperature (T{sub g}). For example, the damage threshold on 05.N indentations which typically initiates at fluences <8 J/cm{sup 2} could be improved >35 J/cm{sup 2} through the use of a {approx} 750 C thermal treatment. Larger fracture networks required longer or higher temperature treatment to achieve similar results. At an annealing temperature > 1100 C, optical microscopy indicates morphological changes in some of the fracture structure of …
Date: March 19, 2012
Creator: Shen, N.; Miller, P. E.; Bude, J. D.; Laurence, T. A.; Suratwala, T. I.; Steele, W. A. et al.
System: The UNT Digital Library
Spurious Shear in Weak Lensing with LSST (open access)

Spurious Shear in Weak Lensing with LSST

The complete 10-year survey from the Large Synoptic Survey Telescope (LSST) will image {approx} 20,000 square degrees of sky in six filter bands every few nights, bringing the final survey depth to r {approx} 27.5, with over 4 billion well measured galaxies. To take full advantage of this unprecedented statistical power, the systematic errors associated with weak lensing measurements need to be controlled to a level similar to the statistical errors. This work is the first attempt to quantitatively estimate the absolute level and statistical properties of the systematic errors on weak lensing shear measurements due to the most important physical effects in the LSST system via high fidelity ray-tracing simulations. We identify and isolate the different sources of algorithm-independent, additive systematic errors on shear measurements for LSST and predict their impact on the final cosmic shear measurements using conventional weak lensing analysis techniques. We find that the main source of the errors comes from an inability to adequately characterise the atmospheric point spread function (PSF) due to its high frequency spatial variation on angular scales smaller than {approx} 10{prime} in the single short exposures, which propagates into a spurious shear correlation function at the 10{sup -4}-10{sup -3} level on …
Date: September 19, 2012
Creator: Chang, C.; Kahn, S.M.; Jernigan, J.G.; Peterson, J.R.; AlSayyad, Y.; Ahmad, Z. et al.
System: The UNT Digital Library
Evaluation Of The Integrated Solubility Model, A Graded Approach For Predicting Phase Distribution In Hanford Tank Waste (open access)

Evaluation Of The Integrated Solubility Model, A Graded Approach For Predicting Phase Distribution In Hanford Tank Waste

The mission of the DOE River Protection Project (RPP) is to store, retrieve, treat and dispose of Hanford's tank waste. Waste is retrieved from the underground tanks and delivered to the Waste Treatment and Immobilization Plant (WTP). Waste is processed through a pretreatment facility where it is separated into low activity waste (LAW), which is primarily liquid, and high level waste (HLW), which is primarily solid. The LAW and HLW are sent to two different vitrification facilities and glass canisters are then disposed of onsite (for LAW) or shipped off-site (for HLW). The RPP mission is modeled by the Hanford Tank Waste Operations Simulator (HTWOS), a dynamic flowsheet simulator and mass balance model that is used for mission analysis and strategic planning. The integrated solubility model (ISM) was developed to improve the chemistry basis in HTWOS and better predict the outcome of the RPP mission. The ISM uses a graded approach to focus on the components that have the greatest impact to the mission while building the infrastructure for continued future improvement and expansion. Components in the ISM are grouped depending upon their relative solubility and impact to the RPP mission. The solubility of each group of components is characterized …
Date: October 19, 2012
Creator: Pierson, Kayla L.; Belsher, Jeremy D. & Seniow, Kendra R.
System: The UNT Digital Library
Corrosion-resistant, high-reflectance Mg/SiC multilayer coatings for solar physics in the 25-80 nm wavelength region (open access)

Corrosion-resistant, high-reflectance Mg/SiC multilayer coatings for solar physics in the 25-80 nm wavelength region

None
Date: August 19, 2012
Creator: Soufli, R & Al, E T
System: The UNT Digital Library
MODELING GAS TRANSPORT AND REACTIONS IN POLYDIMETHYSILOXANE (open access)

MODELING GAS TRANSPORT AND REACTIONS IN POLYDIMETHYSILOXANE

None
Date: July 19, 2012
Creator: Lu, C; Sun, Y; Harley, S J & Glascoe, E A
System: The UNT Digital Library
Multi-field Peeling-ballooning modes simulation (open access)

Multi-field Peeling-ballooning modes simulation

None
Date: September 19, 2012
Creator: Xia, T Y & Xu, X Q
System: The UNT Digital Library
Tunable Plasmonic Nanogap Resonator (open access)

Tunable Plasmonic Nanogap Resonator

None
Date: June 19, 2012
Creator: BOnd, T.; Bora, M.; Chang, A. & Miles, R.
System: The UNT Digital Library
Atmospheric PSF Interpolation for Weak Lensing in Short Exposure Imaging Data (open access)

Atmospheric PSF Interpolation for Weak Lensing in Short Exposure Imaging Data

A main science goal for the Large Synoptic Survey Telescope (LSST) is to measure the cosmic shear signal from weak lensing to extreme accuracy. One difficulty, however, is that with the short exposure time ({approx_equal}15 seconds) proposed, the spatial variation of the Point Spread Function (PSF) shapes may be dominated by the atmosphere, in addition to optics errors. While optics errors mainly cause the PSF to vary on angular scales similar or larger than a single CCD sensor, the atmosphere generates stochastic structures on a wide range of angular scales. It thus becomes a challenge to infer the multi-scale, complex atmospheric PSF patterns by interpolating the sparsely sampled stars in the field. In this paper we present a new method, psfent, for interpolating the PSF shape parameters, based on reconstructing underlying shape parameter maps with a multi-scale maximum entropy algorithm. We demonstrate, using images from the LSST Photon Simulator, the performance of our approach relative to a 5th-order polynomial fit (representing the current standard) and a simple boxcar smoothing technique. Quantitatively, psfent predicts more accurate PSF models in all scenarios and the residual PSF errors are spatially less correlated. This improvement in PSF interpolation leads to a factor of 3.5 …
Date: September 19, 2012
Creator: Chang, C.; Marshall, P.J.; Jernigan, J.G.; Peterson, J.R.; Kahn, S.M.; Gull, S.F. et al.
System: The UNT Digital Library
Heavy-ion-induced modification of structural and mechanical properties of carbon-nanotube aerogels (open access)

Heavy-ion-induced modification of structural and mechanical properties of carbon-nanotube aerogels

None
Date: November 19, 2012
Creator: Charnvanichborikarn, S; Shin, S J; Worsley, M A & Kucheyev, S O
System: The UNT Digital Library