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Theoretical study of the conformation and energy of supercoiled DNA

Description: The two sugar-phosphate backbones of the DNA molecule wind about each other in helical paths. For circular DNA molecules, or for linear pieces of DNA with the ends anchored, the two strands have a well-defined linking number, Lk. If Lk differs from the equilibrium linking number Lk{sub 0}, the molecule is supercoiled. The linking difference {Delta}Lk = Lk-Lk{sub 0} is partitioned between torsional deformation of the DNA, or twist ({Delta}Tw), and a winding of the DNA axis about itself known as … more
Date: January 1, 1992
Creator: Hunt, N. G.
Partner: UNT Libraries Government Documents Department
open access

Reactivity effects of void formations in a solution critical assembly

Description: SHEBA II (Solution High Energy Burst Assembly) was constructed in order to better understand the neutronics of solutions of fissile materials. In order to estimate the effect on criticality from the formation of bubbles, models were devised in MCNP (Monte Carlo Neutron Photon transport code) and THREEDANT (THREE dimensional, Diffusion-Accelerated, Neutral-Particle Transport). It was found that the formation of voids in all but the outside bottom edge of the assembly cylinder tend to act as a ne… more
Date: January 1, 1994
Creator: Walters, S. G.
Partner: UNT Libraries Government Documents Department
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Strange meson spectroscopy in K{omega} and K{phi} at 11 GeV/c and Cherenkov ring imaging at SLD

Description: This thesis consists of two independent parts; development of Cherenkov Ring Imaging Detector (CRID) system and analysis of high-statistics data of strange meson reactions from the LASS spectrometer. Part 1: The CRID system is devoted to charged particle identification in the SLAC Large Detector (SLD) to study e{sup +}e{sup {minus}} collisions at {radical}s = m{sub Z{sup 0}}. By measuring the angles of emission of the Cherenkov photons inside liquid and gaseous radiators, {pi}/K/p separation wi… more
Date: January 1993
Creator: Kwon, Youngjoon
Partner: UNT Libraries Government Documents Department
open access

Isotopic tracer studies of Fischer-Tropsch Synthesis over Ru/TiO{sub 2} catalysts

Description: Fischer-Tropsch synthesis is a process in which CO and H{sub 2} react to give predominantly liquid hydrocarbons. The reaction can be considered a special type of polymerization in which the monomer is produced in situ, and chain growth occurs by a sequence of independently repeated additions of the monomer to the growing chain. A investigation has been conducted to study the CO hydrogenation reaction in order to better understand catalyst deactivation and the elementary surface processes involv… more
Date: January 1, 1992
Creator: Krishna, K. R.
Partner: UNT Libraries Government Documents Department
open access

Sequence modelling and an extensible data model for genomic database

Description: The Human Genome Project (HGP) plans to sequence the human genome by the beginning of the next century. It will generate DNA sequences of more than 10 billion bases and complex marker sequences (maps) of more than 100 million markers. All of these information will be stored in database management systems (DBMSs). However, existing data models do not have the abstraction mechanism for modelling sequences and existing DBMS`s do not have operations for complex sequences. This work addresses the pr… more
Date: January 1, 1992
Creator: Li, Peter Wei-Der
Partner: UNT Libraries Government Documents Department
open access

SAMPLING AND MASS SPECTROMETRY APPROACHES FOR THE DETECTION OF DRUGS AND FOREIGN CONTAMINANTS IN BREATH FOR HOMELAND SECURITY APPLICATIONS

Description: Homeland security relies heavily on analytical chemistry to identify suspicious materials and persons. Traditionally this role has focused on attribution, determining the type and origin of an explosive, for example. But as technology advances, analytical chemistry can and will play an important role in the prevention and preemption of terrorist attacks. More sensitive and selective detection techniques can allow suspicious materials and persons to be identified even before a final destructive … more
Date: January 27, 2009
Creator: Martin, A N
Partner: UNT Libraries Government Documents Department
open access

Measurement of the top quark pair production cross section in proton-antiproton collisions at a center of mass energy of 1.96 TeV, hadronic top decays with the D0 detector

Description: Of the six quarks in the standard model the top quark is by far the heaviest: 35 times more massive than its partner the bottom quark and more than 130 times heavier than the average of the other five quarks. Its correspondingly small decay width means it tends to decay before forming a bound state. Of all quarks, therefore, the top is the least affected by quark confinement, behaving almost as a free quark. Its large mass also makes the top quark a key player in the realm of the postulated Hig… more
Date: January 16, 2009
Creator: Hegeman, Jeroen Guido
Partner: UNT Libraries Government Documents Department
open access

Exclusive B Decays into Final States with Two Charmed Baryons

Description: This Thesis presents measurements of the decays B{sup -} {yields} {Xi}{sub c}{sup 0}{bar {Lambda}}{sub c}{sup -}, {bar B}{sup 0} {yields} {Xi}{sub c}{sup +}{bar {Lambda}}{sub c}{sup -}, B{sup -} {yields} {Lambda}{sub c}{sup +}{bar {Lambda}}{sub c}{sup -} K{sup -}, and {bar B}{sup 0} {yields} {Lambda}{sub c}{sup +}{bar {Lambda}}{sub c}{sup -} K{sub s}{sup 0} based on 228 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the SLAC PEP-II asymmetric-energy B factor… more
Date: January 11, 2010
Creator: Chai, Xuedong
Partner: UNT Libraries Government Documents Department
open access

Measurement of the W boson mass and width using a novel recoil model

Description: This dissertation presents a direct measurement of the W boson mass (M{sub W}) and decay width ({Lambda}{sub W}) in 1 fb{sup -1} of W {yields} e{nu} collider data at D0 using a novel method to model the hadronic recoil. The mass is extracted from fits to the transverse mass M{sub T}, p{sub T}(e), and E{sub T} distributions. The width is extracted from fits to the tail of the M{sub T} distribution. The electron energy measurement is simulated using a parameterized model, and the recoil is modele… more
Date: January 1, 2009
Creator: Wetstein, Matthew J.
Partner: UNT Libraries Government Documents Department
open access

Correlations in bottom quark pair production at the Fermilab Tevatron

Description: I present an analysis of b{bar b} pair production correlations, using dimuon-triggered data collected with the Collider Detector at Fermilab (CDF) in p{bar p} collisions at {radical}s = 1.96 TeV during Run II of the TeVatron. The leading order (LO) and next-to-leading order (NLO) b quark production processes are discriminated by the angular and momentum correlations between the b{bar b} pair. Track-level jets containing a muon are classified by b quark content and used to estimate the momentum … more
Date: January 1, 2009
Creator: Galyardt, Jason Edward
Partner: UNT Libraries Government Documents Department
open access

ROMP-based polymer composites and biorenewable rubbers

Description: This research is divided into two related topics. In the first topic, the synthesis and characterization of novel composite materials reinforced with MWCNTs by ring-opening metathesis polymerization (ROMP) is reported for two ROMP based monomers: dicyclopentadiene (DCPD) and 5-ethylidene-2-norbornene (ENB). Homogeneous dispersion of MWCNTs in the polymer matrices is achieved by grafting norbornene moieties onto the nanotube surface. For the DCPD-based system, the investigation of mechanical pro… more
Date: January 1, 2009
Creator: Jeong, Wonje
Partner: UNT Libraries Government Documents Department
open access

B Flavour Tagging with Artificial Neural Networks for the CDF II Experiment

Description: One of the central questions arising from human curiosity has always been what matter is ultimately made of, with the idea of some kind of elementary building-block dating back to the ancient greek philosophers. Scientific activities of multiple generations have contributed to the current best knowledge about this question, the Standard Model of particle physics. According to it, the world around us is composed of a small number of stable elementary particles: Electrons and two different kinds … more
Date: January 1, 2010
Creator: Schmidt, Andreas
Partner: UNT Libraries Government Documents Department
open access

A Measurement of Neutrino Charged Current Interactions and a Search for Muon Neutrino Disappearance with the Fermilab Booster Neutrino Beam

Description: In this thesis, we report on a measurement of muon neutrino inclusive charged current interactions on carbon in the few GeV region, using the Fermilab Booster Neutrino Beam. The all neutrino mode data collected in the SciBooNE experiment is used for this analysis. We collected high-statistics CC interaction sample at SciBooNE, and extracted energy dependent inclusive charged current interaction rates and cross sections for a wide energy range from 0.25 GeV to {approx}3 GeV. We measure the inter… more
Date: January 1, 2011
Creator: Nakajima, Yasuhiro & U., /Kyoto
Partner: UNT Libraries Government Documents Department
open access

The Need for a Strong Science and Technology Program in the Nuclear Weapons Complex for the 21st Century

Description: In this paper I argue for the need for a strong Science and Technology program in the Nuclear Weapons Complex as the basis for maintaining a credible deterrence capability. The current Nuclear Posture Review establishes a New Triad as the basis for the United States deterrence strategy in a changing security environment. A predictive science capability is at the core of a credible National Nuclear Weapons program in the 21st Century. In absence of nuclear testing, the certification of our curre… more
Date: January 6, 2010
Creator: Garaizar, X
Partner: UNT Libraries Government Documents Department
open access

PDF and QCD effects in the precision measurement of the W boson mass at CDF

Description: A sample of W {yields} e{nu} (W {yields} {mu}{nu}) and Z{sup 0} {yields} e{sup +}e{sup -} (Z{sup 0} {yields} {mu}{sup +}{mu}{sup -}) events recorded by the CDF detector for p{bar p} collisions at {radical}s = 1.96 TeV are used to evaluate the systematic uncertainty in the determination of the W boson mass arising from uncertainties in the parton distribution functions and higher-order QCD effects. The systematic contribution of PDFs is determined to be 10 MeV/c{sup 2} for MSTW2008 NLO and 12 Me… more
Date: January 1, 2011
Creator: Beecher, Daniel & London, /University Coll.
Partner: UNT Libraries Government Documents Department
open access

Precision Measurement of the Mass of the Top Quark in p anti-p Collisions

Description: We report a measurement of the mass of the top quark (m{sub top}) in p{bar p} collisions at a center of mass energy of 1.96 TeV. The analysis is based on p{bar p}{yields}t{bar t}{yields} lepton+jets data recorded with the D0 detector at the Fermilab Tevatron Collider. Events were preselected in the e+jets (913 events/pb of data) and in the {mu}+jets (871 events/pb of data) channels. These were analyzed through a comparison of the matrix element for the production and decay of the t{bar t} state… more
Date: January 1, 2007
Creator: Garcia, Carlos A.
Partner: UNT Libraries Government Documents Department
open access

Delta Electroproduction in 12-C

Description: The Delta-nucleus potential is a crucial element in the understanding of the nuclear system. Previous electroexcitation measurements in the delta region reported a Q2 dependence of the delta mass indicating that this potential is dependent on the momentum of the delta. Such a dependence is not observed for protons and neutrons in the nuclear medium. This thesis presents the experimental study of the electroexcitation of the delta resonance in 12C, performed using the high energy electron beam a… more
Date: January 31, 2003
Creator: McLauchlan, Steven
Partner: UNT Libraries Government Documents Department
open access

Finding the charm in 800 GeV/c p-Cu and p-Be single muon spectra

Description: Fermilab Experiment 866 took single muon data from 800 GeV/c ({radical}s = 38.8 GeV) p-Cu and p-Be interactions in an attempt to extract the inclusive nuclear open charm/anti-charm (D/{bar D}) differential cross sections as a function of p{sub T}. The muons were decay products from semi-leptonic decays of open charm mesons as well as decays from lighter non-charmed mesons ({pi}'s and K's). Data were taken simultaneously from two interaction regions; one of two thin nuclear targets and a copper … more
Date: January 1, 2005
Creator: Klinksiek, Stephen A.
Partner: UNT Libraries Government Documents Department
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