ASIC Development for Three-Dimensional Silicon Imaging Array for Cold Neutrons (open access)

ASIC Development for Three-Dimensional Silicon Imaging Array for Cold Neutrons

An Integrated Circuit (IC) readout chip with four channels arranged so as to receive input charge from the corners of the chip was designed for use with 5- to 7-mm pixel detectors. This Application Specific IC (ASIC) can be used for cold neutron imaging, for study of structural order in materials using cold neutron scattering or for particle physics experiments. The ASIC is fabricated in a 0.5-{micro}m n-well AMI process. The design of the ASIC and the test measurements made is reported. Noise measurements are also reported.
Date: May 19, 2004
Creator: Britton, C.L.; Jagadish, U. & Bryan, W.L.
Object Type: Report
System: The UNT Digital Library
'Shim pulses' for NMR spectroscopy in inhomogeneous magneticfields (open access)

'Shim pulses' for NMR spectroscopy in inhomogeneous magneticfields

NMR spectroscopy conveys information about chemical structure through ppm-scale shifts of the resonance frequency depending on the chemical environment. In order to observe these small shifts, magnets with highly homogeneous magnetic field B{sub 0} are used. The high cost and large size of these magnets are a consequence of the requirement for high homogeneity. In this contribution we introduce a new method for recording high-resolution NMR spectra from samples in inhomogeneous B{sub 0}, opening up the possibility of exploiting magnets of lower homogeneity and cost. Instead of using the traditional B{sub 0} ''shim coils'', adiabatic radiofrequency (RF) pulse sequences and modulated B{sub 0} gradients generated by coils in the probe are used to produce ''shim pulses''. A great deal of work has been devoted to finding methods for retrieving chemical shift information even when B{sub 0} is inhomogeneous. One class of methods relies on zero- or multiple quantum coherences which evolve independently of B{sub 0}. These methods are inherently two-dimensional and the high-resolution information is obtained indirectly. In order to minimize experimental time it is desirable to acquire a high-resolution spectrum directly just as for traditional NMR in homogeneous fields. A further advantage with direct acquisition is that modification of …
Date: May 19, 2004
Creator: Topgaard, Daniel; Martin, Rachel W.; Sakellariou, Dimitris; Meriles, Carlos & Pines, Alexander
Object Type: Article
System: The UNT Digital Library
Clothes washer standards in China -- The problem of water andenergy trade-offs in establishing efficiency standards (open access)

Clothes washer standards in China -- The problem of water andenergy trade-offs in establishing efficiency standards

Currently the sales of clothes washers in China consist ofseveral general varieties. Some use more energy (with or withoutincluding hot water energy use) and some use more water. Both energy andwater are in short supply in China. This poses the question - how do youtrade off water versus energy in establishing efficiency standards? Thispaper discusses how China dealt with this situation and how itestablished minimum efficiency standards for clothes washers.
Date: May 19, 2004
Creator: Biermayer, Peter J. & Lin, Jiang
Object Type: Article
System: The UNT Digital Library
Microwave Scattering System Design for {rho}{sub i}e-Scale Turbulence Measurements on NSTX (open access)

Microwave Scattering System Design for {rho}{sub i}e-Scale Turbulence Measurements on NSTX

Despite suppression of {rho}{sub i}-scale turbulent fluctuations, electron thermal transport remains anomalous in NSTX. For this reason, a microwave scattering system will be deployed to directly observe the w and k spectra of {rho}{sub e}-scale turbulent fluctuations and characterize the effect on electron thermal transport. The scattering system will employ a Gaussian probe beam produced by a high power 280 GHz microwave source. A five-channel heterodyne detection system will measure radial turbulent spectra in the range |k{sub r}| = 0-20 cm{sup -1}. Inboard and outboard launch configurations cover most of the normalized minor radius. Improved spatial localization of measurements is achieved with low aspect ratio and high magnetic shear configurations. This paper will address the global design of the scattering system, such as choice of frequency, size, launching system, and detection system.
Date: May 19, 2004
Creator: Smith, D. R.; Mazzucato, E.; Munsat, T.; Park, H.; Johnson, D.; Lin, L. et al.
Object Type: Report
System: The UNT Digital Library
Analytic, High-beta Solutions of the Helical Grad-Shafranov Equation (open access)

Analytic, High-beta Solutions of the Helical Grad-Shafranov Equation

We present analytic, high-beta ({beta} {approx} O(1)), helical equilibrium solutions for a class of helical axis configurations having large helical aspect ratio, with the helix assumed to be tightly wound. The solutions develop a narrow boundary layer of strongly compressed flux, similar to that previously found in high beta tokamak equilibrium solutions. The boundary layer is associated with a strong localized current which prevents the equilibrium from having zero net current.
Date: May 19, 2004
Creator: Smith, D. R. & Reiman, A. H.
Object Type: Report
System: The UNT Digital Library
Shape Metamorphism Using p-Laplacian Equation (open access)

Shape Metamorphism Using p-Laplacian Equation

We present a new approach for shape metamorphism, which is a process of gradually changing a source shape (known) through intermediate shapes (unknown) into a target shape (known). The problem, when represented with implicit scalar function, is under-constrained, and regularization is needed. Using the p-Laplacian equation (PLE), we generalize a series of regularization terms based on the gradient of the implicit function, and we show that the present methods lack additional constraints for a more stable solution. The novelty of our approach is in the deployment of a new regularization term when p --> infinity which leads to the infinite Laplacian equation (ILE). We show that ILE minimizes the supremum of the gradient and prove that it is optimal for metamorphism since intermediate solutions are equally distributed along their normal direction. Applications of the proposed algorithm for 2D and 3D objects are demonstrated.
Date: May 19, 2004
Creator: Cong, Ge; Esser, Mehmet; Parvin, Bahram & Bebis, George
Object Type: Article
System: The UNT Digital Library
Phylogenetic relationships among amphisbaenian reptiles based on complete mitochondrial genomic sequences (open access)

Phylogenetic relationships among amphisbaenian reptiles based on complete mitochondrial genomic sequences

Complete mitochondrial genomic sequences are reported from 12 members in the four families of the reptile group Amphisbaenia. Analysis of 11,946 aligned nucleotide positions (5,797 informative) produces a robust phylogenetic hypothesis. The family Rhineuridae is basal and Bipedidae is the sister taxon to the Amphisbaenidae plus Trogonophidae. Amphisbaenian reptiles are surprisingly old, predating the breakup of Pangaea 200 million years before present, because successive basal taxa (Rhineuridae and Bipedidae) are situated in tectonic regions of Laurasia and nested taxa (Amphisbaenidae and Trogonophidae) are found in Gondwanan regions. Thorough sampling within the Bipedidae shows that it is not tectonic movement of Baja California away from the Mexican mainland that is primary in isolating Bipes species, but rather that primary vicariance occurred between northern and southern groups. Amphisbaenian families show parallel reduction in number of limbs and Bipes species exhibit parallel reduction in number of digits. A measure is developed for comparing the phylogenetic information content of various genes. A synapomorphic trait defining the Bipedidae is a shift from the typical vertebrate mitochondrial gene arrangement to the derived state of trnE and nad6. In addition, a tandem duplication of trnT and trnP is observed in B. biporus with a pattern of pseudogene …
Date: May 19, 2004
Creator: Macey, J. Robert; Papenfuss, Theodore J.; Kuehl, Jennifer V.; Fourcade, H. Matthew & Boore, Jeffrey L.
Object Type: Article
System: The UNT Digital Library
Genetic variation among agamid lizards of the trapelus agiliscomplex in the caspian-aral basin (open access)

Genetic variation among agamid lizards of the trapelus agiliscomplex in the caspian-aral basin

Allozyme variation is examined in eight populations of Trapelus from the Caspian-Aral Basin of the former USSR. Thirty-one loci (15 variable) exhibit remarkably low levels of genetic variation with only a Nei's genetic distance of 0.117 across 2500 km. An isolated population on the European side of the Caspian Sea is found to phenetically cluster inside the Asian populations examined, suggesting that it should not be considered taxonomically distinct.
Date: May 19, 2004
Creator: Macey, J. Robert & Ananjeva, Natalia B.
Object Type: Article
System: The UNT Digital Library
A SEA FLOOR GRAVITY SURVEY OF THE SLEIPNER FIELD TO MONITOR CO2 MIGRATION (open access)

A SEA FLOOR GRAVITY SURVEY OF THE SLEIPNER FIELD TO MONITOR CO2 MIGRATION

Since 1996, excess CO{sub 2} from the Sleipner natural gas field has been sequestered and injected underground into a porous saline aquifer 1000 m below the seafloor. In 2002, we carried out a high precision micro-gravity survey on the seafloor in order to monitor the injected CO{sub 2}. A repeatability of 5 {micro}Gal in the station averages was observed. This is considerably better than pre-survey expectations. These data will serve as the baseline for time-lapse gravity monitoring of the Sleipner CO{sub 2} injection site. A repeat survey has been scheduled for the summer of 2005. This report covers 9/19/03 to 3/18/04. During this time, significant advancement in the 3-D gravity forward modeling code was made. Testing of the numerical accuracy of the code was undertaken using both a sheet of mass and a frustum of a cone for test cases. These were chosen because of our ability to do an analytic calculation of gravity for comparison. Tests were also done to determine the feasibility of using point mass approximations rather than cuboids for the forward modeling code. After determining that the point mass approximation is sufficient (and over six times faster computationally), several CO{sub 2} models were constructed and the …
Date: May 19, 2004
Creator: Zumberge, Mark; Nooner, Scott & Sasagawa, Glenn
Object Type: Report
System: The UNT Digital Library
Clean Steel: Advancing the State of the Art (TRP 0003) (open access)

Clean Steel: Advancing the State of the Art (TRP 0003)

This project had 3 objectives: (1) to determine the kinetic factors governing inclusion removal from liquid steels at a slag metal interface; (2) to develop a methodology to enable steels of less than 1 ppm total oxygen to be produced with an average inclusion diameter of less than 5 {micro}m; and, (3) to determine the slag-metal interface conditions necessary for ultra clean steels. In objectives 1, and 3, the major finding was that dissolution rates of solid particles in slags were found to be significant in both ladle and tundish slags and must be included in a model to predict steel cleanliness. The work towards objective 2 indicated that liquid steel temperature was a very significant factor in our understanding of clean steel potential and that undercooled steels equilibrated with low oxygen potential inert gases have the potential to be significantly cleaner than current steels. Other work indicated that solidification front velocity could be used to push particles to produce clean steels and that reoxidation must be severely curtailed to allow the potential for clean steels to be realized.
Date: May 19, 2004
Creator: Seetharaman, Sridhar & Cramb, Alan W.
Object Type: Report
System: The UNT Digital Library
A new hypothesis of squamate evolutionary relationships from nuclear and mitochondrial DNA sequence data (open access)

A new hypothesis of squamate evolutionary relationships from nuclear and mitochondrial DNA sequence data

Squamate reptiles serve as model systems for evolutionary studies of a variety of morphological and behavioral traits, and phylogeny is crucial to many generalizations derived from such studies. Specifically, the traditional dichotomy between Iguania and Scleroglossa has been correlated with major evolutionary shifts within Squamata. We present a molecular phylogenetic study of squamates using DNA sequence data from the nuclear genes RAG-1 and c-mos and the mitochondrial ND2 region, sampling all major clades and most major subclades. Monophyly of Iguania, Anguimorpha, and almost all currently recognized squamate families is strongly supported. However, monophyly is rejected for Scleroglossa, Varanoidea, and several other higher taxa, and Iguania is highly nested within Squamata. Limblessness evolved independently in snakes, dibamids, and amphisbaenians, suggesting widespread morphological convergence or parallelism in limbless, burrowing forms. Amphisbaenians are the sister group of lacertids, and snakes are grouped with iguanians and anguimorphs. Dibamids diverged early in squamate evolutionary history. Xantusiidae is the sister taxon of Cordylidae. Studies of functional tongue morphology and feeding mode have found significant differences between Scleroglossa and Iguania, and our finding of a nonmonophyletic Scleroglossa and a highly nested Iguania suggest that similar states evolved separately in Sphenodon and Iguania, and that jaw prehension is …
Date: May 19, 2004
Creator: Townsend, Ted M.; Larson, Allan; Louis, Edward & Macey, J. Robert
Object Type: Article
System: The UNT Digital Library
Stabilizing Grout Compatibility Study (open access)

Stabilizing Grout Compatibility Study

This report provides data that will be used to formulate the stabilizing grout and includes experimental results for Tc-99 stabilization by two reagents, (1) ground granulated blast furnace slag (GGBFS) and (2) surface treated hydroxyapatite (HA). One or both of these reagents are being considered by CH2M HILL for incorporation in the binder portion (matrix portion without sand) of the stabilizing grout. The technical basis for identifying the grout ingredient(s) for stabilizing technetium (Tc-99) will be provided by researchers at the Savannah River Technology Center (SRTC) in a subsequent report.
Date: May 19, 2004
Creator: Harbour, John R.
Object Type: Report
System: The UNT Digital Library
Targeting a Novel Plasmodium falciparum Purine Recycling Pathway with Specific Immucillins (open access)

Targeting a Novel Plasmodium falciparum Purine Recycling Pathway with Specific Immucillins

Plasmodium falciparum is unable to synthesize purine bases and relies upon purine salvage and purine recycling to meet its purine needs. We report that purines formed as products of the polyamine pathway are recycled in a novel pathway in which 5'-methylthioinosine is generated by adenosine deaminase. The action of P. falciparum purine nucleoside phosphorylase is a convergent step of purine salvage, converting both 5'-methylthioinosine and inosine to hypoxanthine. We used accelerator mass spectrometry to verify that 5'-methylthioinosine is an active nucleic acid precursor in P. falciparum. Prior studies have shown that inhibitors of purine salvage enzymes kill malaria, but potent malaria-specific inhibitors of these enzymes have not previously been described. 5'-methylthio-Immucillin-H, a transition state analogue inhibitor that is selective for malarial over human purine nucleoside phosphorylase, kills P. falciparum in culture. Immucillins are currently in clinical trials for other indications and may have application as antimalarials.
Date: May 19, 2004
Creator: Ting, L; Shi, W; Lewandowicz, A; Singh, V; Mwakingwe, A; Birck, M R et al.
Object Type: Article
System: The UNT Digital Library
Hanford Site Climatological Data Summary 2003 with Historical Data (open access)

Hanford Site Climatological Data Summary 2003 with Historical Data

This document presents the climatological data measured at the U.S. Department of Energy’s Hanford Site for calendar year 2003.
Date: May 19, 2004
Creator: Hoitink, Dana J.; Burk, Kenneth W.; Ramsdell, James V. & Shaw, William J.
Object Type: Report
System: The UNT Digital Library
Laser Heated High Density Fluids Probed by Coherent Anti-Stokes Raman Spectroscopy (open access)

Laser Heated High Density Fluids Probed by Coherent Anti-Stokes Raman Spectroscopy

We describe an integrated experimental method of Coherent Antistoke Raman Spectroscopy (CARS), laser-heating and diamond-anvil cell (DAC) technologies probing molecular vibrations of transparent molecular fluids at the pressure-temperature conditions of energetic detonation and Giant planetary interiors. In this method, we use a microfabricated metal toroid to conductively heat a surrounding transparent sample in a DAC, using a CW Nd:YLF laser. The laser is operated at a TEM{sub 01*} mode to match the shape of the toroid and thus produces a uniform heating area. The CARS probe utilizes two pulsed lasers with similar cavity lengths: a commercial narrow-band mode-locked Q-switched Nd:YAG laser and a home-built broadband dye laser. A strong CARS signal is then produced from the sample in the central region of laser-heated metal toroid where the two laser pulses spatially and temporally coincide. In this paper, we will demonstrate that this technique is capable of producing high quality vibrational spectra from nitrogen fluid above 2000 K and 13 GPa, where the application of spontaneous Raman spectroscopy is limited because of intense thermal radiation.
Date: May 19, 2004
Creator: Baer, B J & Yoo, C
Object Type: Article
System: The UNT Digital Library
Monitored Natural Attenuation of ino9rganic Contaminants Treatability Study Final Report (open access)

Monitored Natural Attenuation of ino9rganic Contaminants Treatability Study Final Report

The identification and quantification of key natural attenuation processes for inorganic contaminants at D-Area is detailed herein. Two overarching goals of this evaluation of monitored natural attenuation (MNA) as a remediation strategy were (1) to better define the availability of inorganic contaminants as potential sources for transport to groundwater and uptake by environmental receptors and (2) to understand the site-specific mechanisms controlling attenuation of these inorganic contaminants through tandem geochemical and biological characterization. Data collected in this study provides input for more appropriate site groundwater transport models. Significant natural attenuation is occurring at D-Area as evidenced by relatively low aqueous concentrations of constituents of concern (COCs) (Be, Ni, U, and As) at all locations characterized and the decrease in groundwater concentrations with increasing distance from the source. The observed magnitude of decrease in groundwater concentrations of COCs with distance from the D-Area Coal Pile Runoff Basin (DCPRB) could not be accounted for by the modeled physical attenuation processes of dilution/dispersion. This additional attenuation, i.e., the observed difference between the groundwater concentrations of COCs and the modeled physical attenuation, is due to biogeochemical processes occurring at the D-Area. In tandem geochemical and microbiological characterization studies designed to evaluate the mechanisms contributing …
Date: May 19, 2004
Creator: Crapse, K
Object Type: Report
System: The UNT Digital Library
Global Ocean Circulation Modeling with an Isopycnic Coordinate Model. Final Report for May 1, 1998 - April 30, 2002 (open access)

Global Ocean Circulation Modeling with an Isopycnic Coordinate Model. Final Report for May 1, 1998 - April 30, 2002

The overall aim of this project was to continue development of a global version of the Miami Isopycnic Coordinate Ocean Model (MICOM) with the intent of turning it into a full-fledged oceanic component of an earth system model.
Date: May 19, 2004
Creator: Bleck, R.
Object Type: Report
System: The UNT Digital Library
Pseudopotential theory of Auger processes in CdSe quantum dots (open access)

Pseudopotential theory of Auger processes in CdSe quantum dots

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Date: May 19, 2004
Creator: Wang, Lin-Wang; Califano, Marco; Zunger, Alex & Fraceschetti, Alberto
Object Type: Article
System: The UNT Digital Library
Carbon Sequestration on Surface Mine Lands Quarterly Report (open access)

Carbon Sequestration on Surface Mine Lands Quarterly Report

The January-March 2004 Quarter was dedicated to tree planting activities in two locations in Kentucky. During year one of this project there was no available mine land to plant in the Hazard area so 107 acres were planted in the Martin county mine location. This year 120 acres was planted in the Hazard area to compensate for the prior year and an additional 57 acres was planted on Peabody properties in western Kentucky. An additional set of special plots were established on each of these areas that contained 4800 seedlings each for special carbon sequestration determinations. Plantings were also conducted to continue compaction and water quality studies on two newly established areas as well as confirmed measurements on the first years plantings. Total plantings on this project now amount to 357 acres containing 245,960 tree seedlings.
Date: May 19, 2004
Creator: Graves, Donald H.; Barton, Christopher; Sweigard, Richard & Warner, Richard
Object Type: Report
System: The UNT Digital Library