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Inclusive Measurements of |V(ub)| From BaBar
The Cabibbo-Kobayashi-Maskawa (CKM) matrix element V{sub ub} is a fundamental parameter of the Standard Model, representing the coupling of the b quark to the u quark. It is one of the smallest and least known elements of the CKM matrix. With the increasingly precise measurements of decay-time-dependent CP asymmetries in B-meson decays, in particular the angle {beta} [1, 2], improved measurements of the magnitude of V{sub ub} will allow for stringent experimental tests of the Standard Model mechanism for CP violation [3]. The extraction of |V{sub ub}| is a challenge, both theoretically and experimentally. Theoretically, the weak decay rate for b {yields} uev can be calculated at the parton level. It is proportional to |V{sub ub}|{sup 2} and m{sub b}{sup 5}, where m{sub b} is the b-quark mass. To relate the B-meson decay rate to |V{sub ub}|, the parton-level calculations have to be corrected for perturbative and non-perturbative QCD effects. These corrections can be calculated using various techniques: heavy quark expansions (HQE) [4] and QCD factorization [5]. They make use of specific assumptions and are affected by different uncertainties. It is therefore important to make redundant measurements by using several experimental techniques, and different theoretical frameworks. Experimentally, the principal challenge …
Date:
April 17, 2006
Creator:
Della Ricca, G. & /Trieste U. /INFN, Trieste
Object Type:
Article
System:
The UNT Digital Library
Solid Waste Processing Center Primary Opening Cells Systems, Equipment and Tools
This document addresses the remote systems and design integration aspects of the development of the Solid Waste Processing Center (SWPC), a facility to remotely open, sort, size reduce, and repackage mixed low-level waste (MLLW) and transuranic (TRU)/TRU mixed waste that is either contact-handled (CH) waste in large containers or remote-handled (RH) waste in various-sized packages.
Date:
April 17, 2006
Creator:
Bailey, Sharon A.; Baker, Carl P.; Mullen, O Dennis & Valdez, Patrick LJ
Object Type:
Report
System:
The UNT Digital Library
HIGH LEVEL WASTE (HLW) SLUDGE BATCH 4 (SB4): SELECTING GLASSES FOR A VARIABILITY STUDY
A critical step in the Sludge Batch 4 (SB4) qualification process is to demonstrate the applicability of the durability models, which are used as part of the Defense Waste Processing Facility's (DWPF's) process control strategy, to the frit / SB4 glass system via a variability study. A variability study is an experimentally-driven assessment of the predictability and acceptability of the vitrified waste product quality that is anticipated from the processing of a sludge batch. The quality of the waste form is a measure of its durability as determined by the Product Consistency Test (PCT). At the DWPF, the durability of the vitrified waste product is not directly measured by this test during normal operation. Instead, the durability is predicted using a set of models that relate the PCT response of a glass to the chemical composition of that glass. The main objective of a variability study is to demonstrate that these models are applicable to the glass composition region anticipated during the processing of the sludge batch. The success of this demonstration allows the DWPF to confidently rely on the predictions of the durability/composition models as they are used in the control of the DWPF process. The glass region for …
Date:
August 17, 2006
Creator:
Fox, K; Tommy Edwards, T & David Peeler, D
Object Type:
Report
System:
The UNT Digital Library
Sliding Mode Pulsed Averaging IC Drivers for High Brightness Light Emitting Diodes
This project developed new Light Emitting Diode (LED) driver ICs associated with specific (uniquely operated) switching power supplies that optimize performance for High Brightness LEDs (HB-LEDs). The drivers utilize a digital control core with a newly developed nonlinear, hysteretic/sliding mode controller with mixed-signal processing. The drivers are flexible enough to allow both traditional microprocessor interface as well as other options such as “on the fly” adjustment of color and brightness. Some other unique features of the newly developed drivers include • AC Power Factor Correction; • High power efficiency; • Substantially fewer external components should be required, leading to substantial reduction of Bill of Materials (BOM). Thus, the LED drivers developed in this research : optimize LED performance by increasing power efficiency and power factor. Perhaps more remarkably, the LED drivers provide this improved performance at substantially reduced costs compared to the present LED power electronic driver circuits. Since one of the barriers to market penetration for HB-LEDs (in particular “white” light LEDs) is cost/lumen, this research makes important contributions in helping the advancement of SSL consumer acceptance and usage.
Date:
August 17, 2006
Creator:
Dr. Anatoly Shteynberg, PhD
Object Type:
Report
System:
The UNT Digital Library
Incorporation of aqueous reaction and sorption kinetics andbiodegradation into TOUGHREACT
The needs for considering aqueous and sorption kinetics and microbiological processes arises in many subsurface problems, such as environmental and acid mine remediation. A general rate expression has been implemented into TOUGHREACT, which considers multiple mechanisms(pathways) and includes multiple product, Monod, and inhibition terms. In this paper, the formulation for incorporating kinetic rates among primary species into the mass balance equations is presented. A batch sulfide oxidation problem is simulated. The resulting concentrations are consistent with simple hand calculations. A 1-D reactive transport problem with kinetic biodegradation and sorption was investigated, which models the processes when a pulse of water containing NTA (nitrylotriacetate) and cobalt is injected into a column. The problem has several interacting chemical processes that are common to many environmental problems: biologically-mediated degradation of an organic substrate, bacterial cell growth and decay, metal sorption and aqueous speciation including metal-ligand complexation. The TOUGHREACT simulation results agree very well with those obtained with other simulators.
Date:
April 17, 2006
Creator:
Xu, Tianfu
Object Type:
Article
System:
The UNT Digital Library
Combined Climate and Carbon-Cycle Effects of Large-Scale Deforestation
The prevention of deforestation and promotion of afforestation have often been cited as strategies to slow global warming. Deforestation releases CO{sub 2} to the atmosphere, which exerts a warming influence on Earth's climate. However, biophysical effects of deforestation, which include changes in land surface albedo, evapotranspiration, and cloud cover also affect climate. Here we present results from several large-scale deforestation experiments performed with a three-dimensional coupled global carbon-cycle and climate model. These are the first such simulations performed using a fully three-dimensional model representing physical and biogeochemical interactions among land, atmosphere, and ocean. We find that global-scale deforestation has a net cooling influence on Earth's climate, since the warming carbon-cycle effects of deforestation are overwhelmed by the net cooling associated with changes in albedo and evapotranspiration. Latitude-specific deforestation experiments indicate that afforestation projects in the tropics would be clearly beneficial in mitigating global-scale warming, but would be counterproductive if implemented at high latitudes and would offer only marginal benefits in temperate regions. While these results question the efficacy of mid- and high-latitude afforestation projects for climate mitigation, forests remain environmentally valuable resources for many reasons unrelated to climate.
Date:
October 17, 2006
Creator:
Bala, G.; Caldeira, K.; Wickett, M.; Phillips, T. J.; Lobell, D. B.; Delire, C. et al.
Object Type:
Article
System:
The UNT Digital Library
Boiler Materials for Ultrasupercritical Coal Power Plants
The U.S. Department of Energy (DOE) and the Ohio Coal Development Office (OCDO) have recently initiated a project aimed at identifying, evaluating, and qualifying the materials needed for the construction of the critical components of coal-fired boilers capable of operating at much higher efficiencies than current generation of supercritical plants. This increased efficiency is expected to be achieved principally through the use of ultrasupercritical steam conditions (USC). A limiting factor in this can be the materials of construction. The project goal is to assess/develop materials technology that will enable achieving turbine throttle steam conditions of 760 C (1400 F)/35 MPa (5000 psi). This goal seems achievable based on a preliminary assessment of material capabilities. The project is further intended to build further upon the alloy development and evaluation programs that have been carried out in Europe and Japan. Those programs have identified ferritic steels capable of meeting the strength requirements of USC plants up to approximately 620 C (1150 F) and nickel-based alloys suitable up to 700 C (1300 F). In this project, the maximum temperature capabilities of these and other available high-temperature alloys are being assessed to provide a basis for materials selection and application under a range of …
Date:
July 17, 2006
Creator:
Viswanathan, R.; Coleman, K.; Shingledecker, J.; Sarver, J.; Stanko, G.; Borden, M. et al.
Object Type:
Report
System:
The UNT Digital Library
AMG by element agglomeration and constrained energy minimization interpolation
This paper studies AMG (algebraic multigrid) methods that utilize energy minimization construction of the interpolation matrices locally, in the setting of element agglomeration AMG. The coarsening in element agglomeration AMG is done by agglomerating fine-grid elements, with coarse element matrices defined by a local Galerkin procedure applied to the matrix assembled from the individual fine-grid element matrices. This local Galerkin procedure involves only the coarse basis restricted to the agglomerated element. To construct the coarse basis, one exploits previously proposed constraint energy minimization procedures now applied to the local matrix. The constraints are that a given set of vectors should be interpolated exactly, not only globally, but also locally on every agglomerated element. The paper provides algorithmic details, as well as a convergence result based on a ''local-to-global'' energy bound of the resulting multiple-vector fitting AMG interpolation mappings. A particular implementation of the method is illustrated with a set of numerical experiments.
Date:
February 17, 2006
Creator:
Kolev, T V & Vassilevski, P S
Object Type:
Article
System:
The UNT Digital Library
Public Release of a One Dimensional Version of the Photon Clean Method (PCM1D)
We announce the public release of a one dimensional version of the Photon Clean Method (PCM1D). This code is in the general class of 'inverse Monte Carlo' methods and is specifically designed to interoperate with the public analysis tools available from the Chandra Science Center and the HEASARC. The tool produces models of event based data on a photon by photon basis. The instrument models are based on the standard ARF and RMF fits files. The resulting models have a high number of degrees of freedom of order the number of photons detected providing an alternative analysis compared to the usual method of fitting models with only a few parameters. The original work on this method is described in ADASS 1996 (Jernigan and Vezie).
Date:
October 17, 2006
Creator:
Carpenter, M H & Jernigan, J G
Object Type:
Report
System:
The UNT Digital Library
Experiment on mass-stripping of interstellar cloud following shock passage
The interaction of supernova shocks and interstellar clouds is an important astrophysical phenomenon which can lead to mass-stripping (transfer of material from cloud to surrounding flow, ''mass-loading'' the flow) and possibly increase the compression in the cloud to high enough densities to trigger star formation. Our experiments attempt to simulate and quantify the mass-stripping as it occurs when a shock passes through interstellar clouds. We drive a strong shock using 5 kJ of the 30 kJ Omega laser into a cylinder filled with low-density foam with an embedded 120 {micro}m Al sphere simulating an interstellar cloud. The density ratio between Al and foam is {approx} 9. Time-resolved x-ray radiographs show the cloud getting compressed by the shock (t {approx} 5 ns), undergoing a classical Kelvin-Helmholtz roll-up (12 ns) followed by a Widnall instability (30 ns), an inherently 3d effect that breaks the 2d symmetry of the experiment. Material is continuously being stripped from the cloud at a rate which is shown to be inconsistent with laminar models for mass-stripping (the cloud is fully stripped by 80 ns-100 ns, ten times faster than the laminar model). We present a new model for turbulent mass-stripping that agrees with the observed rate and …
Date:
October 17, 2006
Creator:
Hansen, J. F.; Robey, H. F.; Klein, R. I. & Miles, A. R.
Object Type:
Article
System:
The UNT Digital Library
Crustal thinning between the Ethiopian and East African Plateaus from modeling Rayleigh wave dispersion
The East African and Ethiopian Plateaus have long been recognized to be part of a much larger topographic anomaly on the African Plate called the African Superswell. One of the few places within the African Superswell that exhibit elevations of less than 1 km is southeastern Sudan and northern Kenya, an area containing both Mesozoic and Cenozoic rift basins. Crustal structure and uppermost mantle velocities are investigated in this area by modeling Rayleigh wave dispersion. Modeling results indicate an average crustal thickness of 25 {+-} 5 km, some 10-15 km thinner than the crust beneath the adjacent East African and Ethiopian Plateaus. The low elevations can therefore be readily attributed to an isostatic response from crustal thinning. Low Sn velocities of 4.1-4.3 km/s also characterize this region.
Date:
January 17, 2006
Creator:
Benoit, M H; Nyblade, A A & Pasyanos, M E
Object Type:
Article
System:
The UNT Digital Library
Energy flow in a hadronic cascade: Application to hadroncalorimetry
The hadronic cascade description developed in an earlierpaper is extended to the response of an idealized fine-sampling hadroncalorimeter. Calorimeter response is largely determined by the transferof energy E_e from the hadronic to the electromagnetic sector via \pi0production. Fluctuations in this quantity produce the "constant term" inhadron calorimeter resolution. The increase of its fractional mean, f_\rmem^0= \vevE_e/E, with increasing incident energy E causes the energydependence of the \pi/e ratio in a noncompensating calorimeter. The meanhadronic energy fraction, f_h0 = 1-f_\rm em0, was shown to scaleverynearly as a power law in E: f_h0 = (E/E_0)m-1, where E_0\approx1~;GeV forpions, and m\approx0.83. It follows that \pi/e=1-(1-h/e)(E/E_0)m-1, whereelectromagnetic and hadronic energy deposits are detected withefficiencies e and h, respectively. Fluctuations in these quantities,along with sampling fluctuations, are in corporated to give an overallunderstanding of resolution, which is different from the usual treatmentsin interesting ways. The conceptual framework is also extended to theresponse to jets and the difference between pi and presponse.
Date:
May 17, 2006
Creator:
Groom, Donald E.
Object Type:
Article
System:
The UNT Digital Library
Nanoporous Metal - Combining Strength and Porosity
Recent nanomechanical tests on submicron metal columns and wires have revealed a dramatic increase in yield strength with decreasing sample size. This effect seems to be related to the increased strength observed in metals on decreasing grain size or film thickness, and has been explained by a dislocation nucleation/activation controlled plasticity regime in small sample volumes. The question arises whether one can utilize this new size effect to design materials with improved bulk properties. Here, we demonstrate that nanoporous metal foams can be envisioned as a three-dimensional network of ultrahigh-strength nanocolumns/wires, thus bringing together two seemingly conflicting properties: high strength and high porosity. Specifically, we studied the mechanical properties of nanoporous (np) Au using a combination of nanoindentation and column microcompression tests, as well as supplemental molecular dynamics simulations. We find that np-Au can be as strong as bulk Au, despite being a highly porous material, and that the ligaments in np-Au approach the theoretical yield strength of Au. The combination of high yield strength and high porosity can be used to design a new generation of energy absorbing materials for various engineering applications.
Date:
May 17, 2006
Creator:
Biener, J; Hodge, A M; Hayes, J R; Volkert, C A; Zepeda-Ruiz, L A; Hamza, A V et al.
Object Type:
Article
System:
The UNT Digital Library
Z' Phenomenology and the LHC
A brief pedagogical overview of the phenomenology of Z{prime} gauge bosons is ILC in determining Z{prime} properties is also discussed. and explore in detail how the LHC may discover and help elucidate the models, review the current constraints on the possible properties of a Z{prime} nature of these new particles. We provide an overview of the Z{prime} studies presented. Such particles can arise in various electroweak extensions of that have been performed by both ATLAS and CMS. The role of the the Standard Model (SM). We provide a quick survey of a number of Z{prime}.
Date:
October 17, 2006
Creator:
Rizzo, Thomas G.
Object Type:
Article
System:
The UNT Digital Library
Center for Catalysis at Iowa State University
The overall objective of this proposal is to enable Iowa State University to establish a Center that enjoys world-class stature and eventually enhances the economy through the transfer of innovation from the laboratory to the marketplace. The funds have been used to support experimental proposals from interdisciplinary research teams in areas related to catalysis and green chemistry. Specific focus areas included: • Catalytic conversion of renewable natural resources to industrial materials • Development of new catalysts for the oxidation or reduction of commodity chemicals • Use of enzymes and microorganisms in biocatalysis • Development of new, environmentally friendly reactions of industrial importance These focus areas intersect with barriers from the MYTP draft document. Specifically, section 2.4.3.1 Processing and Conversion has a list of bulleted items under Improved Chemical Conversions that includes new hydrogenation catalysts, milder oxidation catalysts, new catalysts for dehydration and selective bond cleavage catalysts. Specifically, the four sections are: 1. Catalyst development (7.4.12.A) 2. Conversion of glycerol (7.4.12.B) 3. Conversion of biodiesel (7.4.12.C) 4. Glucose from starch (7.4.12.D) All funded projects are part of a soybean or corn biorefinery. Two funded projects that have made significant progress toward goals of the MYTP draft document are: Catalysts to convert …
Date:
October 17, 2006
Creator:
Kraus, George A.
Object Type:
Report
System:
The UNT Digital Library
TRITIUM EFFECTS ON WELDMENT FRACTURE TOUGHNESS
The effects of tritium on the fracture toughness properties of Type 304L stainless steel and its weldments were measured. Fracture toughness data are needed for assessing tritium reservoir structural integrity. This report provides data from J-Integral fracture toughness tests on unexposed and tritium-exposed weldments. The effect of tritium on weldment toughness has not been measured until now. The data include tests on tritium-exposed weldments after aging for up to three years to measure the effect of increasing decay helium concentration on toughness. The results indicate that Type 304L stainless steel weldments have high fracture toughness and are resistant to tritium aging effects on toughness. For unexposed alloys, weldment fracture toughness was higher than base metal toughness. Tritium-exposed-and-aged base metals and weldments had lower toughness values than unexposed ones but still retained good toughness properties. In both base metals and weldments there was an initial reduction in fracture toughness after tritium exposure but little change in fracture toughness values with increasing helium content in the range tested. Fracture modes occurred by the dimpled rupture process in unexposed and tritium-exposed steels and welds. This corroborates further the resistance of Type 304L steel to tritium embrittlement. This report fulfills the requirements for the …
Date:
July 17, 2006
Creator:
Morgan, M; Michael Tosten, M & Scott West, S
Object Type:
Report
System:
The UNT Digital Library
Spectral Predictors
Many scientific, imaging, and geospatial applications produce large high-precision scalar fields sampled on a regular grid. Lossless compression of such data is commonly done using predictive coding, in which weighted combinations of previously coded samples known to both encoder and decoder are used to predict subsequent nearby samples. In hierarchical, incremental, or selective transmission, the spatial pattern of the known neighbors is often irregular and varies from one sample to the next, which precludes prediction based on a single stencil and fixed set of weights. To handle such situations and make the best use of available neighboring samples, we propose a local spectral predictor that offers optimal prediction by tailoring the weights to each configuration of known nearby samples. These weights may be precomputed and stored in a small lookup table. We show that predictive coding using our spectral predictor improves compression for various sources of high-precision data.
Date:
November 17, 2006
Creator:
Ibarria, L; Lindstrom, P & Rossignac, J
Object Type:
Article
System:
The UNT Digital Library
Living with genome instability: the adaptation of phytoplasmas todiverse environments of their insect and plant hosts
Phytoplasmas (Candidatus Phytoplasma, Class Mollicutes) cause disease in hundreds of economically important plants, and are obligately transmitted by sap-feeding insects of the order Hemiptera, mainly leafhoppers and psyllids. The 706,569-bp chromosome and four plasmids of aster yellows phytoplasma strain witches broom (AY-WB) were sequenced and compared to the onion yellows phytoplasma strain M (OY-M) genome. The phytoplasmas have small repeat-rich genomes. The repeated DNAs are organized into large clusters, potential mobile units (PMUs), which contain tra5 insertion sequences (ISs), and specialized sigma factors and membrane proteins. So far, PMUs are unique to phytoplasmas. Compared to mycoplasmas, phytoplasmas lack several recombination and DNA modification functions, and therefore phytoplasmas probably use different mechanisms of recombination, likely involving PMUs, for the creation of variability, allowing phytoplasmas to adjust to the diverse environments of plants and insects. The irregular GC skews and presence of ISs and large repeated sequences in the AY-WB and OY-M genomes are indicative of high genomic plasticity. Nevertheless, segments of {approx}250 kb, located between genes lplA and glnQ are syntenic between the two phytoplasmas, contain the majority of the metabolic genes and no ISs. AY-WB is further along in the reductive evolution process than OY-M. The AY-WB genome is {approx}154 …
Date:
February 17, 2006
Creator:
Bai, Xiaodong; Zhang, Jianhua; Ewing, Adam; Miller, Sally A.; Radek, Agnes; Shevchenko, Dimitriy et al.
Object Type:
Article
System:
The UNT Digital Library
Impact of Quaternary Climate on Seepage at Yucca Mountain, Nevada
Uranium-series ages, oxygen-isotopic compositions, and uranium contents were determined in outer growth layers of opal and calcite from 0.5- to 3-centimeter-thick mineral coatings hosted by lithophysal cavities in the unsaturated zone at Yucca Mountain, Nevada, the proposed site of a permanent repository for high-level radioactive waste. Micrometer-scale growth layering in the minerals was imaged using a cathodoluminescence detector on a scanning electron microscope. Determinations of the chemistry, ages, and delta oxygen-18 values of the growth layers were conducted by electron microprobe analysis and secondary ion mass spectrometry techniques at spatial resolutions of 1 to about 20 micrometers ({micro}m) and 25 to 40 micrometers, respectively. Growth rates for the last 300 thousand years (k.y.) calculated from about 300 new high-resolution uranium-series ages range from approximately 0.5 to 1.5 {micro}m/k.y. for 1- to 3-centimeter-thick coatings, whereas coatings less than about I-centimeter-thick have growth rates less than 0.5 {micro}m/k.y. At the depth of the proposed repository, correlations of uranium concentration and delta oxygen-18 values with regional climate records indicate that unsaturated zone percolation and seepage water chemistries have responded to changes in climate during the last several hundred thousand years.
Date:
March 17, 2006
Creator:
Whelan, J. F.; Paces, J. B.; Neymark, L. A.; Schmitt, A. K. & Grove, M.
Object Type:
Report
System:
The UNT Digital Library
Seminole Sentinel (Seminole, Tex.), Vol. 97, No. 98, Ed. 1 Sunday, September 17, 2006
Semiweekly newspaper from Seminole, Texas that includes local, state, and national news along with extensive advertising.
Date:
September 17, 2006
Creator:
Wright, Dustin
Object Type:
Newspaper
System:
The Portal to Texas History
Seminole Sentinel (Seminole, Tex.), Vol. 98, No. 20, Ed. 1 Sunday, December 17, 2006
Semiweekly newspaper from Seminole, Texas that includes local, state, and national news along with extensive advertising.
Date:
December 17, 2006
Creator:
Wright, Dustin
Object Type:
Newspaper
System:
The Portal to Texas History
Seminole Sentinel (Seminole, Tex.), Vol. 97, No. 63, Ed. 1 Wednesday, May 17, 2006
Semiweekly newspaper from Seminole, Texas that includes local, state, and national news along with extensive advertising.
Date:
May 17, 2006
Creator:
Wright, Dustin
Object Type:
Newspaper
System:
The Portal to Texas History
[Three attendees at a table, BHM banquet 2006]
A photograph of women sitting at a table during the 2006 Black History Month banquet. There are glasses of tea and water in front of them and coffee cups as well. Another table is visible behind them.
Date:
February 17, 2006
Creator:
University of North Texas. Multicultural Center.
Object Type:
Image
System:
The UNT Digital Library
[Guest and Cheylon Brown during BHM banquet 2006]
A photograph of a guest and Cheylon Brown standing together in the ballroom at the 2006 Black History Month banquet. The man is wearing a black coat and a brown plaid scarf and Brown is wearing a pink and yellow outfit.
Date:
February 17, 2006
Creator:
University of North Texas. Multicultural Center.
Object Type:
Image
System:
The UNT Digital Library