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Development of trigger software for the silicon and fibre trackers and a study of B meson lifetimes for the D0 experiment
The D0 detector has recently undergone a major upgrade to maximize its potential to fully exploit Run II at the Tevatron 2 TeV proton-antiproton collider. The upgrade includes a completely new central tracking system with an outer scintillating fiber tracker and an inner silicon vertex detector. This thesis describes the development of the software to ''unpack'' the raw data from the central tracking detectors into a useful form, and the development of the Level 3 trigger algorithms to cluster the hit information from these detectors. One of the many areas of physics that is being studied by the D0 experiment is the physics of B mesons, particularly that involving CP violation. The second part of the thesis details a constrained mass fitting tool written to aid the reconstruction of B particles, and a Monte Carlo study into measuring the lifetime of B{sup +} and B{sup 0} mesons. This thesis lays the foundations for the means by which physics is extracted from the vast amount of Tevatron data--the trigger--and illustrates how analyses will proceed through the key reconstruction of heavy quarks.
Date:
January 1, 2002
Creator:
Illingworth, Robert Arthur
System:
The UNT Digital Library
Near Threshold electroproduction of the Omega Meson at Momentum Transfer Q2=0.5 (GeV/c)2
Jefferson Lab kaon experiments E91016/E93018 produced data on both strangeness and vector meson electroproduction. The latter part of the experiments was focused on the electroproduction of the omega meson for momentum transfer Q 2 near 0.5 (GeV/c) 2. This reaction was selected from the inelastic ep channel, H-1 (e, e' p)X, by performing involved signal background separation. Tagging the omega meson production only on electron and proton not only introduced appreciable statistical error but also a sizeable systematic uncertainty due to the background removal. Nevertheless, the analysis yielded angular distributions of the differential cross section in the threshold regime extracted with an unprecedented granularity and relatively small errors.
Date:
January 1, 2002
Creator:
Ambrosewicz, P.
System:
The UNT Digital Library
Regional Breakability in Emu (Dromaius novaehollandiae) Eggshells
Thesis written by a student in the UNT Honors College discussing the soundness of emu eggshells.
Date:
2002
Creator:
Khorrami, Sheva
System:
The UNT Digital Library
A study of B(s)0 to J/psi phi in the D0 experiment and an example of HEP technology transfer
After years of preparation, data taking with the upgraded D0 detector at the Tevatron proton-antiproton collider has begun. The large amount of data produced in a p{bar p}-collider requires sophisticated triggers to filter out the interesting events. Described in this thesis is the development of trigger software for the newly implemented Silicon Microstrip Tracker. D0 is a multi-purpose detector with a broad physics program. one area being studied at D0 is B mesons. An algorithm for reconstructing the B{sub s}{sup 0} and B{sub d}{sup 0} mesons and for measuring their lifetimes has been developed and is described in this thesis. The results suggest that an improvement of the current lifetime measurements can be achieved within the next two years. The reconstruction of a J/{psi} meson forms the basis for a wide range of b-physics. Data taken with the muon system during the commissioning period of the detector has been analyzed and a signal for the J/{psi} meson has been found. Systematic transfer of HEP technologies into other areas and their commercial exploitation plays an important role in the future of particle physics. An area of particular interest is DNA sequencing as shown by the recent completion of the sequencing of …
Date:
January 1, 2002
Creator:
Bauer, Daniela Ursula
System:
The UNT Digital Library
Large-Eddy Simulation of the Evolving Stable Boundary Layer Over Flat Terrain
The stable boundary layer (SBL) in the atmosphere is of considerable interest because it is often the worse case scenario for air pollution studies and health effect assessments associated with the accidental release of toxic material. Traditional modeling approaches used in such studies do not simulate the non-steady character of the velocity field, and hence often overpredict concentrations while underpredicting spatial coverage of potentially harmful concentrations of airborne material. The challenge for LES is to be able to resolve the rather small energy-containing eddies of the SBL while still maintaining an adequate domain size. This requires that the subgrid-scale (SGS) parameterization of turbulence incorporate an adequate representation of turbulent energy transfer. Recent studies have shown that both upscale and downscale energy transfer can occur simultaneously, but that overall the net transfer is downscale. Including the upscale transfer of turbulent energy (energy backscatter) is particularly important near the ground and under stably-stratified conditions. The goal of this research is to improve the ability to realistically simulate the SBL. The large-eddy simulation (LES) approach with its subgrid-scale (SGS) turbulence model does a better job of capturing the temporally and spatially varying features of the SBL than do Reynolds-averaging models. The scientific objectives …
Date:
January 2, 2002
Creator:
Townsend, Richard Townsend
System:
The UNT Digital Library
Microearthquake Study of the Salton Sea Geothermal Field, California: Evidence of Stress Triggering
A digital network of 24 seismograph stations was operated from September 15, 1987 to September 30, 1988, by Lawrence Livermore National Laboratory and Unocal as part of the Salton Sea Scientific Drilling Project to study seismicity related to tectonics and geothermal activity near the drilling site. More than 2001 microearthquakes were relocated in this study in order to image any pervasive structures that may exist within the Salton Sea geothermal field. First, detailed velocity models were obtained through standard 1-D inversion techniques. These velocity models were then used to relocate events using both single event methods and Double-Differencing, a joint hypocenter location method. An anisotropic velocity model was built from anisotropy estimates obtained from well logs within the study area. During the study period, the Superstition wills sequence occurred with two moderate earthquakes of MS 6.2 and MS 6.6. These moderate earthquakes caused a rotation of the stress field as observed from the inversion of first motion data from microearthquakes at the Salton Sea geothermal field. Coulomb failure analysis also indicates that microearthquakes occurring after the Superstition Hills sequence are located within a region of stress increase suggesting stress triggering caused by the moderate earthquakes.
Date:
February 1, 2002
Creator:
Holland, Austin Adams
System:
The UNT Digital Library
Superconducting High Energy Resolution Gamma-ray Spectrometers
We have demonstrated that a bulk absorber coupled to a TES can serve as a good gamma-ray spectrometer. Our measured energy resolution of 70 eV at 60 keV is among the best measurements in this field. We have also shown excellent agreement between the noise predictions and measured noise. Despite this good result, we noted that our detector design has shortcomings with a low count rate and vulnerabilities with the linearity of energy response. We addressed these issues by implementation of an active negative feedback bias. We demonstrated the effects of active bias such as additional pulse shortening, reduction of TES change in temperature during a pulse, and linearization of energy response at low energy. Linearization at higher energy is possible with optimized heat capacities and thermal conductivities of the microcalorimeter. However, the current fabrication process has low control and repeatability over the thermal properties. Thus, optimization of the detector performance is difficult until the fabrication process is improved. Currently, several efforts are underway to better control the fabrication of our gamma-ray spectrometers. We are developing a full-wafer process to produce TES films. We are investigating the thermal conductivity and surface roughness of thicker SiN membranes. We are exploring alternative …
Date:
February 22, 2002
Creator:
Chow, Daniel Tun Lai
System:
The UNT Digital Library
Interfacial and near interfacial crack growth phenomena in metal bonded alumina
Metal/ceramic interfaces can be found in many engineering applications including microelectronic packaging, multi-layered films, coatings, joints, and composite materials. In order to design reliable engineering systems that contain metal/ceramic interfaces, a comprehensive understanding of interfacial and near interfacial failure mechanisms is necessary.
Date:
March 1, 2002
Creator:
Kruzic, Jamie Joseph
System:
The UNT Digital Library
Study of the Delta (1232) Using Double Polarization Asymmetries
An extensive experimental program to measure the spin structure of the nucleus is underway in Hall B at Jefferson Lab using a polarized electron beam incident on a polarized target. Spin degrees of freedom offer the possibility to test, in an independent way, existing models of resonance electro-production. The present analysis selects the Delta{sup +} (1232) in the exclusive channel {rvec p}({rvec e}, e'p)pi{sup 0} from data of the EG1 run period, taken in the Fall of 1998, to extract single and double asymmetries in a Q{sup 2} range from 0.5 to 1.5 GeV{sup 2}/c{sup 2}. Results of the asymmetries are presented as a function of momentum transfer Q{sup 2}. A comparison with the Effective Lagrangian Model by R. Davidson and N. Mukhopadhyay, the unitary isobar model MAID, and the dynamic model by Sato and Lee was performed. The data were found to be generally in good agreement with the models and a x{sup 2} comparison preferred the Sato-Lee model, which is tailored for the Delta (1232) photo- and electro-production. The present results are the first measurement of asymmetries for the exclusive reaction {rvec p}({rvec e}, e'p)pi{sup 0} and will provide new constraints for the models.
Date:
March 1, 2002
Creator:
Biselli, Angela
System:
The UNT Digital Library
Kevin
Short story written by a student in the UNT Honors College about a group of people observing a friend as he delves into films and the occult.
Date:
March 18, 2002
Creator:
Saxon, Jared
System:
The UNT Digital Library
Arrival Survival and Adaptation: The Quest for Gender Identity Among Female Mexican Immigrants
Honors thesis written by a student in the UNT Honors College discussing anthropological issues for female anthropologists of color while researching the lives of several Latinas in Denton, Texas.
Date:
Spring 2002
Creator:
Vega, Sujey
System:
The UNT Digital Library
Educational Corporate Social Responsibility in Mexico
Thesis written by a student in the UNT Honors College discussing Mexico's educational system and corporate social responsibility programs and whether these actually respond to the needs of Mexican schools.
Date:
Spring 2002
Creator:
Cunningham, Kenda
System:
The UNT Digital Library
Social Implications of Modeling
Thesis written by a student in the UNT Honors College discussing the interaction of humans with the environment, including issues with water, consumption, reproduction, and groundwater in Texas.
Date:
Spring 2002
Creator:
Reams, Randall S.
System:
The UNT Digital Library
Self- and zinc diffusion in gallium antimonide
The technological age has in large part been driven by the applications of semiconductors, and most notably by silicon. Our lives have been thoroughly changed by devices using the broad range of semiconductor technology developed over the past forty years. Much of the technological development has its foundation in research carried out on the different semiconductors whose properties can be exploited to make transistors, lasers, and many other devices. While the technological focus has largely been on silicon, many other semiconductor systems have applications in industry and offer formidable academic challenges. Diffusion studies belong to the most basic studies in semiconductors, important from both an application as well as research standpoint. Diffusion processes govern the junctions formed for device applications. As the device dimensions are decreased and the dopant concentrations increased, keeping pace with Moore's Law, a deeper understanding of diffusion is necessary to establish and maintain the sharp dopant profiles engineered for optimal device performance. From an academic viewpoint, diffusion in semiconductors allows for the study of point defects. Very few techniques exist which allow for the extraction of as much information of their properties. This study focuses on diffusion in the semiconductor gallium antimonide (GaSb). As will become …
Date:
March 26, 2002
Creator:
Nicols, Samuel Piers
System:
The UNT Digital Library
Heterotic orbifolds
A review of orbifold geometry is given, followed by a review of the construction of four-dimensional heterotic string models by compactification on a six-dimensional Z{sub 3} orbifold. Particular attention is given to the details of the transition from a classical theory to a first-quantized theory. Subsequently, a discussion is given of the systematic enumeration of all standard-like three generation models subject to certain limiting conditions. it is found that the complete set is described by 192 models, with only five possibilities for the hidden sector gauge group. It is argued that only four of the hidden sector gauge groups are viable for dynamical supersymmetry breaking, leaving only 175 promising models in the class. General features of the spectra of matter states in all 175 models are discussed. Twenty patterns of representations are found to occur. Accommodation of the Minimal Supersymmetric Standard Model (MSSM) spectrum is addressed. States beyond those contains in the MSSM and nonstandard hypercharge normalization are shown to be generic, though some models do allow for the usual hypercharge normalization found in SU(5) embeddings of the Standard Model gauge group. Only one of the twenty patterns of representations, comprising seven of the 175 models, is found to be …
Date:
April 1, 2002
Creator:
Giedt, Joel
System:
The UNT Digital Library
Ability Estimation Under Different Item Parameterization and Scoring Models
A Monte Carlo simulation study investigated the effect of scoring format, item parameterization, threshold configuration, and prior ability distribution on the accuracy of ability estimation given various IRT models. Item response data on 30 items from 1,000 examinees was simulated using known item parameters and ability estimates. The item response data sets were submitted to seven dichotomous or polytomous IRT models with different item parameterization to estimate examinee ability. The accuracy of the ability estimation for a given IRT model was assessed by the recovery rate and the root mean square errors. The results indicated that polytomous models produced more accurate ability estimates than the dichotomous models, under all combinations of research conditions, as indicated by higher recovery rates and lower root mean square errors. For the item parameterization models, the one-parameter model out-performed the two-parameter and three-parameter models under all research conditions. Among the polytomous models, the partial credit model had more accurate ability estimation than the other three polytomous models. The nominal categories model performed better than the general partial credit model and the multiple-choice model with the multiple-choice model the least accurate. The results further indicated that certain prior ability distributions had an effect on the accuracy …
Date:
May 2002
Creator:
Si, Ching-Fung B.
System:
The UNT Digital Library
Aerosol Property Comparison Within and Above the ABL at the ARM Program SGP Site
This thesis determines what, if any, measurements of aerosol properties made at the Earth surface are representative of those within the entire air column. Data from the Atmospheric Radiation Measurement site at the Southern Great Plains, the only location in the world where ground-based and in situ airborne measurements are routinely made. Flight legs during the one-year period from March 2000 were categorized as either within or above the atmospheric boundary layer (ABL) by use of an objective mixing height determination technique. Correlations between aerosol properties measured at the surface and those within and above the ABL were computed. Aerosol extensive and intensive properties measured at the surface were found representative of values within the ABL, but not of within the free atmosphere.
Date:
May 1, 2002
Creator:
Delle Monache, L
System:
The UNT Digital Library
An Analysis of the Effectiveness of Computer Assisted Instruction in General Chemistry at an Urban University.
The science-major General Chemistry sequence offered at the University of Houston has been investigated with respect to the effectiveness of recent incorporation of various levels of computer technology. As part of this investigation, questionnaire responses, student evaluations and grade averages and distributions from up to the last ten years have been analyzed and compared. Increased use of web-based material is both popular and effective, particularly with respect to providing extra information and supplemental questions. Instructor contact via e-mail is also well-received. Both uses of technology should be encouraged. In contrast, electronic classroom presentation is less popular. While initial use may lead to improved grades and retention, these levels decrease quickly, possibly due to a reduction in instructor spontaneity.
Date:
May 2002
Creator:
McGuffey, Angela
System:
The UNT Digital Library
And Drops of Rain Fall Like Tears: A Composition for Electroacoustic Music and Video
And Drops of Rain Fall Like Tears is a composition for electroacoustic music with an optional ambient video component. The composition consists of a single movement electroacoustic work twenty-two minutes in duration. The piece creates an immersive sonic environment within the confines of a typical concert space, thereby recreating the powerful temper and subtle beauty of nature from different sonic perspectives. The paper is divided into four chapters, each discussing an element of the piece in detail. The introduction presents background information and compositional approach for the composition. Chapters 1 through 4 present detailed information related to the creation of both the electroacoustic music and video elements of the piece. Chapter 4 contains relevant information to the performance of the piece.
Date:
May 2002
Creator:
Thompson, Michael Allen
System:
The UNT Digital Library
Application of the Finite Element Method to Some Simple Systems in One and Two Dimensions.
The finite element method (FEM) is reviewed and applied to the one-dimensional eigensystems of the isotropic harmonic oscillator, finite well, infinite well and radial hydrogen atom, and the two-dimensional eigensystems of the isotropic harmonic oscillator and the propagational modes of sound in a rectangular cavity. Computer codes that I developed were introduced and utilized to find accurate results for the FEM eigensolutions. One of the computer codes was modified and applied to the one-dimensional unbound quantum mechanical system of a square barrier potential and also provided accurate results.
Date:
May 2002
Creator:
Hunnell, Jason C.
System:
The UNT Digital Library
Approach to Quantum Information starting from Bell's Inequality (Part I) and Statistical Analysis of Time Series Corresponding to Complex Processes (Part II)
Access:
Use of this item is restricted to the UNT Community
I: Quantum information obeys laws that subtly extend those governing classical information, making possible novel effect such as cryptography and quantum computation. Quantum computations are extremely sensitive to disruption by interaction of the computer with its environment, but this problem can be overcome by recently developed quantum versions of classical error-correcting codes and fault-tolerant circuits. Based on these ideas, the purpose of this paper is to provide an approach to quantum information by analyzing and demonstrating Bell's inequality and by discussing the problems related to decoherence and error-correcting. II: The growing need for a better understanding of complex processes has stimulated the development of new and more advanced data analysis techniques. The purpose of this research was to investigate some of the already existing techniques (Hurst's rescaled range and relative dispersion analysis), to develop a software able to process time series with these techniques, and to get familiar with the theory of diffusion processes.
Date:
May 2002
Creator:
Failla, Roberto
System:
The UNT Digital Library
Are the Needs of North Dakota's Aging Population with Developmental Disabilities Being Overlooked?
Access:
Use of this item is restricted to the UNT Community
North Dakota is faced with the challenge of meeting the needs of its growing population of elderly persons aging with a developmental disability. The challenge of creating new service models presents itself to professionals in the fields of Aging and Developmental Disabilities. Traditionally, the aging person with a developmental disability has been sent to nursing homes or grouped into community programs with younger persons with developmental disability. North Dakota is looking toward the future of caring for this special population through integration with elderly without disabilities.
Date:
May 2002
Creator:
Clark, Amy Klein
System:
The UNT Digital Library
Attrition Rates of Teachers Trained in Alternative Teacher Certification Programs, Those Trained in the Centers for the Professional Development of Teachers, and Those Trained in Traditional University Programs.
Access:
Use of this item is restricted to the UNT Community
This study uses teacher employment data provided by the State Board for Educator Certification to examine the similarities and differences between initial employment and attrition rates of teachers trained in three prevalent types of Texas teacher preparation programs; alternative certification programs (ACP), the centers for professional development of teachers (CPDT), and traditional certification programs (TCP). The population for the study includes all Texas teachers who completed training in these programs in 1995, 1996, and 1997. The study found that ACP participants gain employment as Texas public school teachers at a significantly higher rate than their CPDT and TCP trained peers in year-one after completion of their training. However, ACP completers experience higher attrition rates in each of the subsequent years investigated. The study concludes that the overall cumulative attrition rate of new teachers trained in these programs is not as pronounced as originally presumed, but that low production levels cannot keep up with the growing demand for new teachers. Teacher preparation program leaders must seek ways to recruit and train more teachers.
Date:
May 2002
Creator:
Harris, Steven A.
System:
The UNT Digital Library
Autoradiographic Localization of Carbachol-Induced Second Messenger Response in the Rat Spinal Cord Following Inflammation.
This study examined central mechanisms of persistent pain using an autoradiographic technique to localize phosphoinositide hydrolysis (PI) in the rat spinal cord dorsal horn. The lateral half of laminae I-II showed the highest levels of baseline PI turnover and carbachol-stimulated PI turnover in normal animals as well as after inflammation. Inflammation resulted in increased baseline PI turnover in this region of the ipsilateral (76%) and contralateral (65%) dorsal horns. Carbachol increased PI turnover in this region in normal rats (55%) and following inflammation (ipsilateral: 46%, contralateral: 45%). The absolute magnitudes of these increases were 1.85, 2.71, and 2.51 nCi/mg, respectively. The results of this study demonstrate the involvement of PI turnover in neural mechanisms of persistent pain, and provide evidence for the involvement of cholinergic systems in this process. Because spinal cholinergic systems have been reported to be anti-nociceptive, the present results appear to reflect an upregulation of anti-nociceptive activity in response to inflammation. Thus, the spinal cholinergic system may be a regulatory site within the anti-nociceptive pathway, and may provide an attractive target for the development of new therapeutic agents.
Date:
May 2002
Creator:
Moore, Jack
System:
The UNT Digital Library