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Search for Anomalous WW/WZ {r_arrow} e{nu}jj Production at D0; Busqueda de Produccion Anomala WW/WZ {r_arrow}e{nu}jj en D-Zero

Description: A search for anomalous WW and WZ production in p{anti p} collisions at {radical}s = 1.8 TeV using the D0 detector at Fermilab is presented. With a data sample of p{anti p} {r_arrow} e{nu}jjX events corresponding to an integrated luminosity of 76.5 {+-} 4.1pb{sup {minus}1}. 399 candidate events were identified, from which 387.1 {+-} 39.8 events were estimated to be background. No deviations from the Standard Model were seen, which predicts 16.2 {+-} 2.7 events. The 95% CL limit on the cross sect… more
Date: February 1, 1997
Creator: Hernandez, A. S.
Partner: UNT Libraries Government Documents Department
open access

A Next-to-Leading-Order QCD Analysis of Neutrino-Iron Structure Functions at the Tevatron

Description: Nucleon structure functions measured in neutrino-iron and antineutrino-iron charged-current interactions are presented. The data were taken in two high-energy high-statistics runs by the LAB-E detector at the Fermilab Tevatron. Structure functions are extracted from a sample of 950,000 neutrino and 170,000 antineutrino events with neutrino energies from 30 to 360 GeV. The structure functions F{sub 2} and xF{sub 3} are compared with the predictions of perturbative Quantum Chromodynamics (PQCD). … more
Date: June 1, 1997
Creator: Seligman, W. G.
Partner: UNT Libraries Government Documents Department
open access

Laser: a Tool for Optimization and Enhancement of Analytical Methods

Description: In this work, we use lasers to enhance possibilities of laser desorption methods and to optimize coating procedure for capillary electrophoresis (CE). We use several different instrumental arrangements to characterize matrix-assisted laser desorption (MALD) at atmospheric pressure and in vacuum. In imaging mode, 488-nm argon-ion laser beam is deflected by two acousto-optic deflectors to scan plumes desorbed at atmospheric pressure via absorption. All absorbing species, including neutral molecul… more
Date: January 1, 1997
Creator: Preisler, Jan
Partner: UNT Libraries Government Documents Department
open access

Strongly-interacting color-singlet exchange in {anti p}-p collisions at {radical}s = 1800 GeV

Description: Results are presented from an analysis of the particle multiplicity between high transverse energy jets in {anti p}-p collisions at {radical}s = 1,800 GeV. The data were collected using the D0 Detector at Fermi National Accelerator Laboratory. The authors observe an excess of events at low multiplicity which is consistent with strongly interacting color-singlet exchange. The fraction of events due to color-singlet exchange is measured as a function of the transverse energy and rapidity separati… more
Date: December 1, 1997
Creator: Thomas, T.L.T.
Partner: UNT Libraries Government Documents Department
open access

Measurements and analysis of end-to-end Internet dynamics

Description: Accurately characterizing end-to-end Internet dynamics - the performance that a user actually obtains from the lengthy series of network links that comprise a path through the Internet - is exceptionally difficult, due to the network`s immense heterogeneity. At the heart of this work is a `measurement framework` in which a number of sites around the Internet host a specialized measurement service. By coordinating `probes` between pairs of these sites one can measure end-to-end behavior along O(… more
Date: April 1, 1997
Creator: Paxson, V.
Partner: UNT Libraries Government Documents Department
open access

A search for chargino-neutralino production at the Fermilab Tevatron Collider

Description: We have searched for evidence of supersymmetry with the Collider Detector at Fermilab using trilepton events in p{anti p} collisions at {radical}s = 1.8 TeV. In the Minimal Supersymmetric Standard Model (MSSM), we expect trilepton events from chargino-neutralino ({tilde {xi}}{sup {+-}}{sub 1}{tilde {xi}}{sup 0}{sub 2}) pair production, with subsequent decay into leptons. In all possible combinations of electron and muon channels, we observe no candidate events in 107 pb{sup -1} of data. We pres… more
Date: December 1, 1997
Creator: Tannenbaum, B.
Partner: UNT Libraries Government Documents Department
open access

Transport in arrays of submicron Josephson junctions over a ground plane

Description: One-dimensional (1D) and two-dimensional (2D) arrays of Al islands linked by submicron Al/Al{sub x}O{sub y}/Al tunnel junctions were fabricated on an insulating layer grown on a ground plane. The arrays were cooled to temperatures as low as 20 mK where the Josephson coupling energy E{sub J} of each junction and the charging energy E{sub C} of each island were much greater than the thermal energy k{sub B}T. The capacitance C{sub g} between each island and the ground plane was much greater than t… more
Date: December 1, 1997
Creator: Ho, Teressa Rae
Partner: UNT Libraries Government Documents Department
open access

Two-dimensional nuclear magnetic resonance of quadrupolar systems

Description: This dissertation describes two-dimensional nuclear magnetic resonance theory and experiments which have been developed to study quadruples in the solid state. The technique of multiple-quantum magic-angle spinning (MQMAS) is extensively reviewed and expanded upon in this thesis. Specifically, MQMAS is first compared with another technique, dynamic-angle spinning (DAS). The similarity between the two techniques allows us to extend much of the DAS work to the MQMAS case. Application of MQMAS to … more
Date: September 17, 1997
Creator: Wang, Shuanhu
Partner: UNT Libraries Government Documents Department
open access

Development in the design and performance of gas avalanche microdetectors (MSGC, MGC, and MDOT)

Description: There has been continuing development of generic classes of microstrip gas chambers (MSGCs), microgap gas chambers (MGCs) and microdot gas chambers (MDOTs) at Lawrence Berkeley National Laboratory (LBNL) over the past few years, to improve such detectors beyond their present capabilities, to produce detectors suitable for use in current or upcoming experiments, and to allow a basis for new R&D developments which may incorporate these detectors as part of the system. All of these new detectors a… more
Date: December 1, 1997
Creator: Cho, Hyo-Sung
Partner: UNT Libraries Government Documents Department
open access

The development of potassium tantalate niobate thin films for satellite-based pyroelectric detectors

Description: Potassium tantalate niobate (KTN) pyroelectric detectors are expected to provide detectivities, of 3.7 x 10{sup 11} cmHz {sup {1/2}}W{sup {minus}1} for satellite-based infrared detection at 90 K. The background limited detectivity for a room-temperature thermal detector is 1.8 x 10{sup 10} cmHz{sup {1/2}}W{sup {minus}1}. KTN is a unique ferroelectric for this application because of the ability to tailor the temperature of its pyroelectric response by adjusting its ratio of tantalum to niobium. … more
Date: May 1997
Creator: Cherry, H. B. B.
Partner: UNT Libraries Government Documents Department
open access

Near-ground cooling efficacies of trees and high-albedo surfaces

Description: Daytime summer urban heat islands arise when the prevalence of dark-colored surfaces and lack of vegetation make a city warmer than neighboring countryside. Two frequently-proposed summer heat island mitigation measures are to plant trees and to increase the albedo (solar reflectivity) of ground surfaces. This dissertation examines the effects of these measures on the surface temperature of an object near the ground, and on solar heating of air near the ground. Near-ground objects include peopl… more
Date: May 1, 1997
Creator: Levinson, R.M.
Partner: UNT Libraries Government Documents Department
open access

Digital signal processing control of induction machine`s torque and stator flux utilizing the direct stator flux field orientation method

Description: This paper presents a review of the Direct Stator Flux Field Orientation control method. This method can be used to control an induction motor`s torque and flux directly and is the application of interest for this thesis. This control method is implemented without the traditional feedback loops and associated hardware. Predictions are made, by mathematical calculations, of the stator voltage vector. The voltage vector is determined twice a switching period. The switching period is fixed through… more
Date: April 1, 1997
Creator: Seiz, J.B.
Partner: UNT Libraries Government Documents Department
open access

Search for anomalous couplings in the decay of polarized Z bosons to tau lepton pairs

Description: Using a sample of 4,500 polarized Z decays to {tau} lepton pairs accumulated with the SLD detector at the SLAC Linear Collider (SLC) in 1993-95, a search has been made for anomalous couplings in the neutral current reaction e{sup +}e{sup {minus}}{yields}{tau}{sup +}{tau}{sup {minus}}. A measurement of the CP violating Weak Electric Dipole Moment (WEDM) and the CP conserving Weak Magnetic Dipole Moment (WMDM) of the {tau} lepton has been performed by considering the transverse spin polarization … more
Date: June 1, 1997
Creator: Torrence, E.C.
Partner: UNT Libraries Government Documents Department
open access

Synthesis and characterization of nickel hydroxide powders for battery application

Description: The primary objective of this research was to investigate the synthesis and characterization of Ni(OH){sub 2} powders by homogeneous precipitation. Previous research of the same method showed conflicting results and complete characterization of the particle morphology was not carried out. This study has produced precipitates having a composition of 2Ni(OH){sub 2}{center_dot}Ni(HCO{sub 3}){sub 1.85}(NO{sub 3}){sub 0.15}. The XRD patterns showed peaks commonly observed for {alpha}-Ni(OH){sub 2}. … more
Date: October 8, 1997
Creator: Widjaja, A.
Partner: UNT Libraries Government Documents Department
open access

The interaction of katabatic winds and mountain waves

Description: The variation in the oft-observed, thermally-forced, nocturnal katabatic winds along the east side of the Rocky Mountains can be explained by either internal variability or interactions with various other forcings. Though generally katabatic flows have been studied as an entity protected from external forcing by strong thermal stratification, this work investigates how drainage winds along the Colorado Front Range interact with, in particular, topographically forced mountain waves. Previous wor… more
Date: January 1, 1997
Creator: Poulos, G.S.
Partner: UNT Libraries Government Documents Department
open access

Construction of artificial pigment-protein antennae

Description: Photosynthesis is a complex process which results in the conversion of solar radiation into chemical energy. This chemical energy is then used as the free energy source for all living organisms. In its basic form, photosynthesis can be described as the light-activated synthesis of carbohydrates from the simple molecules of water and carbon dioxide: 6H{sub 2}O + 6 CO{sub 2} light C{sub 6}H{sub 12}O{sub 6} + 6 O{sub 2} This basic mechanism actually requires numerous reaction steps. The two primar… more
Date: January 10, 1997
Creator: Sibbald, J.
Partner: UNT Libraries Government Documents Department
open access

Microdosimetric investigations at the Fast Neutron Therapy Facility at Fermilab

Description: Microdosimetry was used to investigate three issues at the neutron therapy facility (NTF) at Fermilab. Firstly, the conversion factor from absorbed dose in A-150 tissue equivalent plastic to absorbed dose in ICRU tissue was determined. For this, the effective neutron kerma factor ratios, i.e. oxygen tissue equivalent plastic and carbon to A-150 tissue equivalent plastic, were measured in the neutron beam. An A-150 tissue equivalent plastic to ICRU tissue absorbed dose conversion factor of 0.92 … more
Date: December 31, 1997
Creator: Langen, K.M.
Partner: UNT Libraries Government Documents Department
open access

Improved resins and novel materials and methods for solid phase extraction and high performance liquid chromatography

Description: Solid-phase extraction (SPE) has grown to be one of the most widely used methods for isolation and preconcentration of a vast range of compounds from aqueous solutions. By modifying polymeric SPE resins with chelating functional groups, the selective uptake of metals was accomplished. The resin, along with adsorbed metals, was vaporized in the ICP and detection of the metals was then possible using either mass or emission spectroscopy. Drug analyses in biological fluids have received heightened… more
Date: October 8, 1997
Creator: Freeze, R.
Partner: UNT Libraries Government Documents Department
open access

Measurements of delayed neutron parameters for U-235 and Np-237

Description: Delayed neutrons are emitted by excited nuclei formed in beta decay of fission products called delayed neutron precursors. About 1% of the total neutrons released in fission are delayed neutrons; however, this small fraction plays an important role in nuclear reactor control. The delayed neutrons determine the time-dependent behavior of reactors, and knowledge of parameters used to predict neutron emission rate is essential for establishing reactivity worths. The delayed neutron yields, decay c… more
Date: July 1997
Creator: Loaiza, D.
Partner: UNT Libraries Government Documents Department
open access

Molecular beam studies of unimolecular and bimolecular chemical reaction dynamics using VUV synchrotron radiation as a product probe

Description: This dissertation describes the use of a new molecular beam apparatus designed to use tunable VUV synchrotron radiation for photoionization of the products from scattering experiments. The apparatus was built at the recently constructed Advanced Light Source at Lawrence Berkeley National Laboratory, a third generation 1-2 GeV synchrotron radiation source. The new apparatus is applied to investigations of the dynamics of unimolecular reactions, photodissociation experiments, and bimolecular reac… more
Date: August 1, 1997
Creator: Blank, D.A.
Partner: UNT Libraries Government Documents Department
open access

Studies of structures and phase transitions in pyrrhotite

Description: This report contains a general introduction, the experimental section, general conclusions, and two appendices: using projection operators to construct the basis functions and the magnetic transition of bulk pyrrhotite samples in the low-temperature range. Four chapters have been removed for separate processing. They are: From pyrrhotite to troilite: An application of the Landau theory of phase transitions; Phase transition in near stoichiometric iron sulfide; A ordering, incommensuration and p… more
Date: March 31, 1997
Creator: Li, F.
Partner: UNT Libraries Government Documents Department
open access

Nonlinear response of superconductors to alternating fields and currents

Description: This report discusses the following topics on superconductivity: nonlinearities in hard superconductors such as surface impedance of a type II superconductimg half space and harmonic generation and intermodulation due to alternating transport currents; and nonlinearities in superconducting weak links such as harmonic generation by a long Josephson Junction in a superconducting slab.
Date: October 8, 1997
Creator: McDonald, J.
Partner: UNT Libraries Government Documents Department
open access

A search for charmless dihadron decays of neutral b-hadrons

Description: A search for charmless dihadron decays of neutral b-hadrons was performed using data obtained from 800 GeV/c proton-gold interactions. The following upper limits on the b-hadron branching ratios (including charge conjugates) were obtained at the 90% confidence limit: Br(B{sub s} {yields} K{sup +}K{sup {minus}}) + r{sub s} x Br(B{sub d} {yields} {pi}{sup +}{pi}{sup {minus}}) < 2.0 x 10{sup {minus}3}; Br(B{sub d} {yields} K{sup +}K{sup {minus}}) < 9.5 x 10{sup {minus}4}; Br(B{sub s} {yields}{pi}{… more
Date: March 1, 1997
Creator: Misawa, Shigeki
Partner: UNT Libraries Government Documents Department
open access

Presentation of dynamically overlapping auditory messages in user interfaces

Description: This dissertation describes a methodology and example implementation for the dynamic regulation of temporally overlapping auditory messages in computer-user interfaces. The regulation mechanism exists to schedule numerous overlapping auditory messages in such a way that each individual message remains perceptually distinct from all others. The method is based on the research conducted in the area of auditory scene analysis. While numerous applications have been engineered to present the user wi… more
Date: September 1, 1997
Creator: Papp, A.L.
Partner: UNT Libraries Government Documents Department
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