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open access

Noise Considerations in Nuclear Pulse Amplifiers

Description: The effects of certain pulse-shaping networks on the signal-to-noise ratio of a nuclear pulse amplifier were considered. The shaping networks discussed are: equal RC-integrating and RC-differentiating time constant, single- delay-line clipper and RC integrator, and doubledelay-line clipper and RC integrator. The effects of these networks on the signal, when high count rates and overload pulses are present, were also considered. Equations and curves were developed for the energy resolution (sign… more
Date: December 20, 1961
Creator: Landis, D. A.
Partner: UNT Libraries Government Documents Department
open access

Use of a semiconductor laser in infrared spectroscopy

Description: A semiconductor laser has certain properties which makes its use desirable as a continuous monitor of atmospheric pollutants. Its energy output is concentrated in widely separated energy modes of very narrow bandwidths (less than 10/sup -5/ cm/sup -1/) which can be centered on one infrared absorption line of one gas. This makes the laser quite selective. The energy in each mode is typically greater than 200 ..mu.. watts, and, because of the laser's small size, its light energy can be colli… more
Date: December 1, 1977
Creator: Morris, R. N.
Partner: UNT Libraries Government Documents Department
open access

Inductively coupled plasma--atomic emission spectrometry: trace elements in oil matrices

Description: The simultaneous determination of up to 20 trace elements in various oil matrices by inductively coupled plasma-atomic emission spectrometry is reported. The oil matrices investigated were lubricating oils (for wear metals), fuel oil, centrifuged coal liquefaction product, crude soybean oil, and commercial edible oils. The samples were diluted with appropriate organic solvents and injected into the plasma as an aerosol generated by a pneumatic nebulization technique. Detection limits of the 28 … more
Date: December 1, 1977
Creator: Peterson, C. A.
Partner: UNT Libraries Government Documents Department
open access

Analytical applications of resins containing amide and polyamine functional groups

Description: A dibutyl amide resin is used for the separation of uranium(VI), thorium(IV), and zirconium(IV) from each other and several other metal ions. Uranium(VI) and thorium(IV) are determined in the presence of large excesses of foreign metal ions and anions. A practical application of the amide resin is studied by determining uranium in low grade uranium ores. The amide resin is also used for the selective concentration of gold(III) from sea water.
Date: December 1, 1977
Creator: Orf, G. M.
Partner: UNT Libraries Government Documents Department
open access

Lanthanide extraction with 2,5-dimethyl-2-hydroxyhexanoic acid

Description: This research is concerned with the solvent extraction into chloroform of the lanthanides, using 2,5-dimethyl-2-hydroxyhexanoic acid (DMHHA). This acid is the first ..cap alpha..-hydroxy aliphatic acid to be studied as an extracting agent for the lanthanides. The chloroform-water DMHHA partition constant was determined to be 1.0 (at 0.1 M ionic strength and 25/sup 0/C). The acid dimerizes in chloroform with a constant of 56. The light lanthanides can be extracted into chloroform by forming comp… more
Date: December 1, 1977
Creator: Miller, J. H.
Partner: UNT Libraries Government Documents Department
open access

Interpretation of time domain electromagnetic soundings near geological contacts

Description: Lateral changes in geology pose a serious problem in data interpretation for any surface geophysical method. Although many geophysical techniques are designed to probe vertically, the source signal invariably spreads laterally, so any lateral variations in geology will affect the measurements and interpretation. This problem is particularly acute for controlled source electromagnetic soundings because only a few techniques are available to interpret the data if lateral effects are present. In t… more
Date: December 1, 1991
Creator: Wilt, Michael Joseph
Partner: UNT Libraries Government Documents Department
open access

Multiconfigurational electronic wavefunctions in the full optimized reaction space: the isomerization of nitrosyl hydride to nitrogen hydroxide in the lowest singlet and triplet states

Description: Energy curves are determined for the lowest singlet and triplet states of the HNO molecule. The geometry is varied in that the hydrogen moves through 13 positions around the NO core to describe the isomerization reaction HNO yields HON. Quantitatively determined are the stable and metastable equilibrium positions in both states, the energy differences between these two equilibrium positions and between the two states, and the barriers with respect to isomerization. The calculations are carried … more
Date: December 1, 1977
Creator: Dombek, M. G.
Partner: UNT Libraries Government Documents Department
open access

Electronic transitions of some pi-molecular charge transfer complexes. [Anthracene--pyromellitic dianhydride (PMDA) or pyrene--PMDA in naphthalene--PMDA host]

Description: A unique phonon progression in the phosphorescence spectrum of pyrene-PMDA (Py-PMDA) in naphthalene-PMDA (N-PMDA) is reported. Calculations of the electron-phonon coupling strength parameter for the ground and excited states indicate strong coupling for the fractional CT contribution of Py-PMDA to the observed phosphorescent state. Model calculations indicate that the observed low frequency phonon mode corresponds to a low energy rotation of the rigid guest complex and not a symmetric donor-acc… more
Date: December 1, 1977
Creator: Beckman, R. L.
Partner: UNT Libraries Government Documents Department
open access

A search for sterile neutrinos in MINOS

Description: MINOS, the Main Injector Neutrino Oscillation Search, is a long baseline neutrino oscillation experiment based at Fermilab National Accelerator Laboratory. The experiment uses a neutrino beam, which is measured 1 km downstream from its origin in the Near detector at Fermilab and then 735 km later in the Far detector at the Soudan mine. By comparing these two measurements, MINOS can attain a very high precision for parameters in the atmospheric sector of neutrino oscillations. In addition to pre… more
Date: December 1, 2007
Creator: Osiecki, Thomas Henry
Partner: UNT Libraries Government Documents Department
open access

Measurements of Direct CP Violation, CPT Symmetry, and Other Parameters in the Neutral Kaon System

Description: The authors present precision measurements of the direct CP violation parameter, Re({epsilon}{prime}/{epsilon}), the kaon parameters, {Delta}m and {tau}{sub S}, and the CPT tests, {phi}{sub {+-}} and {Delta}{phi}, in neutral kaon decays. These results are based on the full dataset collected by the KTeV experiment at Fermi National Accelerator Laboratory during 1996, 1997, and 1999. This dataset contains {approx} 15 million K {yields} {pi}{sup 0}{pi}{sup 0} decays and {approx} 69 million K {yiel… more
Date: December 1, 2007
Creator: Worcester, Elizabeth Turner
Partner: UNT Libraries Government Documents Department
open access

Processing and Protection of Rare Earth Permanent Magnet Particulate for Bonded Magnet Applications

Description: Rapid solidification of novel mixed rare earth-iron-boron, MRE{sub 2}Fe{sub 14}B (MRE = Nd, Y, Dy; currently), magnet alloys via high pressure gas atomization (HPGA) have produced similar properties and structures as closely related alloys produced by melt spinning (MS) at low wheel speeds. Recent additions of titanium carbide and zirconium to the permanent magnet (PM) alloy design in HPGA powder (using He atomization gas) have made it possible to achieve highly refined microstructures with mag… more
Date: December 1, 2007
Creator: Sokolowski, Peter Kelly
Partner: UNT Libraries Government Documents Department
open access

M5Si3(M=Ti, Nb, Mo) Based Transition-Metal Silicides for High Temperature Applications

Description: Transition metal silicides are being considered for future engine turbine components at temperatures up to 1600 C. Although significant improvement in high temperature strength, room temperature fracture toughness has been realized in the past decade, further improvement in oxidation resistance is needed. Oxidation mechanism of Ti{sub 5}Si{sub 3}-based alloys was investigated. Oxidation behavior of Ti{sub 5}Si{sub 3}-based alloy strongly depends on the atmosphere. Presence of Nitrogen alters th… more
Date: December 1, 2007
Creator: Tang, Zhihong
Partner: UNT Libraries Government Documents Department
open access

A measurement of the top quark mass in 1.96 TeV proton-antiproton collisions using a novel matrix element method

Description: A measurement of the top quark mass in t{bar t} {yields} l + jets candidate events, obtained from p{bar p} collisions at {radical}s = 1.96 TeV at the Fermilab Tevatron using the CDF II detector, is presented. The measurement approach is that of a matrix element method. For each candidate event, a two dimensional likelihood is calculated in the top pole mass and a constant scale factor, 'JES', where JES multiplies the input particle jet momenta and is designed to account for the systematic uncer… more
Date: December 1, 2007
Creator: Freeman, John C.
Partner: UNT Libraries Government Documents Department
open access

Analysis of Protein-RNA and Protein-Peptide Interactions in Equine Infectious Anemia

Description: Macromolecular interactions are essential for virtually all cellular functions including signal transduction processes, metabolic processes, regulation of gene expression and immune responses. This dissertation focuses on the characterization of two important macromolecular interactions involved in the relationship between Equine Infectious Anemia Virus (EIAV) and its host cell in horse: (1) the interaction between the EIAV Rev protein and its binding site, the Rev-responsive element (RRE) and … more
Date: December 1, 2007
Creator: Lee, Jae-Hyung
Partner: UNT Libraries Government Documents Department
open access

Using Drell-Yan to probe the underlying event in Run II at Collider Detector at Fermilab (CDF)

Description: We study the behavior of charged particles produced in association with Drell-Yan lepton-pairs in the region of the Z-boson in proton-antiproton collisions at 1.96 TeV. We use the direction of the Z-boson in each event to define 'toward', 'away', and 'transverse' regions. For Drell-Yan production (excluding the leptons) both the 'toward' and 'transverse' regions are very sensitive to the 'underlying event', which is defined as everything except the two hard scattered components. The data are co… more
Date: December 1, 2008
Creator: Kar, Deepak
Partner: UNT Libraries Government Documents Department
open access

Control of Laser Plasma Based Accelerators up to 1 GeV

Description: This dissertation documents the development of a broadband electron spectrometer (ESM) for GeV class Laser Wakefield Accelerators (LWFA), the production of high quality GeV electron beams (e-beams) for the first time in a LWFA by using a capillary discharge guide (CDG), and a statistical analysis of CDG-LWFAs. An ESM specialized for CDG-LWFAs with an unprecedented wide momentum acceptance, from 0.01 to 1.1 GeV in a single shot, has been developed. Simultaneous measurement of e-beam spectra and … more
Date: December 3, 2007
Creator: Nakamura, Kei
Partner: UNT Libraries Government Documents Department
open access

A Measurement of the muon neutrino charged current quasielastic interaction and a test of Lorentz violation with the MiniBooNE experiment

Description: The Mini-Booster neutrino experiment (MiniBooNE) at Fermi National Accelerator Laboratory (Fermilab) is designed to search for {nu}{sub {mu}} {yields} {nu}{sub e} appearance neutrino oscillations. Muon neutrino charged-current quasi-elastic (CCQE) interactions ({nu}{sub {mu}} + n {yields} {mu} + p) make up roughly 40% of our data sample, and it is used to constrain the background and cross sections for the oscillation analysis. Using high-statistics MiniBooNE CCQE data, the muon-neutrino CCQE c… more
Date: December 1, 2008
Creator: Katori, Teppei
Partner: UNT Libraries Government Documents Department
open access

Measurements of CP asymmetries and branching fractions of two-body charmless decays of B^0 and B^0_s mesons

Description: The thesis is organized as follows: Chapter 1 describes the theoretical framework of non-leptonic B{sub (s)}{sup 0} {yields} H{sup +}h{prime}{sup -} decays, with a simple overview of the CP violation mechanism within the Standard Model and of the most used phenomenological approaches in the evaluation of strong interaction contributions. The chapter contains also a review of the theoretical expectations and the current experimental measurements along with a discussion about the importance of st… more
Date: December 1, 2007
Creator: Morello, Michael Joseph & /Pisa, Scuola Normale Superiore
Partner: UNT Libraries Government Documents Department
open access

An atmospheric muon neutrino disappearance measurement with the MINOS far detector

Description: It is now widely accepted that the Standard Model assumption of massless neutrinos is wrong, due primarily to the observation of solar and atmospheric neutrino flavor oscillations by a small number of convincing experiments. The MINOS Far Detector, capable of observing both the outgoing lepton and associated showering products of a neutrino interaction, provides an excellent opportunity to independently search for an oscillation signature in atmospheric neutrinos. To this end, a MINOS data set … more
Date: December 1, 2007
Creator: Gogos, Jeremy Peter
Partner: UNT Libraries Government Documents Department
open access

Mechanisms Associated with Rumpling of Pt-Modified Beta-NiAl Coatings

Description: The formation of surface undulations (i.e. rumpling) at the bond coat/thermally grown oxide (TGO) interface has been shown to cause failure by spallation of the ceramic top coat in aero-turbine systems. Many mechanisms have been proposed concerning the cause of these surface distortions; however, there is little agreement on what may be the dominating cause of the rumpling behavior. Of there mechanisms, the reversible phase transformation from a cubic {beta}-NiAl structure to a face centered te… more
Date: December 1, 2007
Creator: Henderkott, Joseph Peter
Partner: UNT Libraries Government Documents Department
open access

Sum Frequency Generation Vibrational Spectroscopy Studies on ModelPeptide Adsorption at the Hydrophobic Solid-Water and HydrophilicSolid-Water Interfaces

Description: Sum frequency generation (SFG) vibrational spectroscopy has been used to study the interfacial structure of several polypeptides and amino acids adsorbed to hydrophobic and hydrophilic surfaces under a variety of experimental conditions. Peptide sequence, peptide chain length, peptide hydrophobicity, peptide side-chain type, surface hydrophobicity, and solution ionic strength all affect an adsorbed peptide's interfacial structure. Herein, it is demonstrated that with the choice of simple, model… more
Date: December 19, 2007
Creator: York, Roger L.
Partner: UNT Libraries Government Documents Department
open access

Study of CP violation in Bx to J/psi phi decays at DZero

Description: In a universe dominated by matter, the source of CP violation may explain one of the greatest mysteries in particle physics: what happened to the antimatter? The Standard Model successfully describes CP violation in the B{sup +} and B{sub d}{sup 0} systems, yet insufficiently accounts for the observed matter-antimatter asymmetry. The Standard Model predicts a small value of CP violation in the B{sub s}{sup 0} meson system, which has only recently been experimentally tested. A measurement of lar… more
Date: December 1, 2008
Creator: Strom, Derek A.
Partner: UNT Libraries Government Documents Department
open access

Nanocrystal Solar Cells

Description: This dissertation presents the results of a research agenda aimed at improving integration and stability in nanocrystal-based solar cells through advances in active materials and device architectures. The introduction of 3-dimensional nanocrystals illustrates the potential for improving transport and percolation in hybrid solar cells and enables novel fabrication methods for optimizing integration in these systems. Fabricating cells by sequential deposition allows for solution-based assembly of… more
Date: December 15, 2006
Creator: Gur, Ilan
Partner: UNT Libraries Government Documents Department
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