285 Matching Results

Search Results

Reaction of Tris(cyclopentadienyl)uranium compounds with amines, azides, and related ligands

Description: The trivalent uranium compound, (MeC{sub 5}H{sub 4}){sub 3}U(thf), serves as a one- or two-electron reducing agent towards azides, RN{sub 3}. These reactions produce either the uranium(IV) azide, (MeC{sub 5}H{sub 4}){sub 3}UN{sub 3}, or uranium(V) imides, (MeC{sub 5}H{sub 4}){sub 3}UNR. The role of steric and electronic effects upon this reaction has been investigated using several series of azides. For Me{sub 3}XN{sub 3}, the imides are produced when X = C or Si, both products are formed when X = Ge, and the azide is produced when X = Sn. For Ph{sub 3}XN{sub 3}, the azide is produced when X = C or Sn. For Ph{sub 3-x}CH{sub 3}N{sub 3}, the imide is produced when x = 2 and both compounds are produced when x = 1. For substituted phenylazides, RC{sub 6}H{sub 4}N{sub 3}, only the imides are produced. The magnetic properties of uranium diimides, ((MeC{sub 5}H{sub 4}){sub 3}U){sub 2}({mu}-NRN), were investigated. Several uranium(III) amines, (MeC{sub 5}H{sub 4}){sub 3}U(NH{sub 2}R), were produced from (MeC{sub 5}H{sub 4}){sub 3}U(thf) and RNH{sub 2}, and NH{sub 3} was found to be a better ligand towards (MeC{sub 5}H{sub 4}){sub 3}U than is PMe{sub 3}.
Date: December 1, 1989
Creator: Rosen, Robert Keith
Partner: UNT Libraries Government Documents Department

A small low energy cyclotron for radioisotope measurements

Description: Direct detection of {sup 14}C by accelerator mass spectrometry has proved to be a much more sensitive method for radiocarbon dating than the decay counting method invented earlier by Libby. A small cyclotron (the cyclotrino'') was proposed for direct detection of radiocarbon in 1980. This combined the suppression of background through the use of negative ions, which had been used effectively in tandem accelerators, with the high intrinsic mass resolution of a cyclotron. Development of a small electrostatically-focused cyclotron for use as a mass spectrometer was previously reported but the sensitivity needed for detection of {sup 14}C at natural abundance was not achieved. The major contributions of this work are the integration of a high current external ion source with a small flat-field, electrostatically-focused cyclotron to comprise a system capable of measuring {sup 14}C at natural levels, and the analysis of ion motion in such a cyclotron, including a detailed analysis of phase bunching and its effect on mass resolution. A high current cesium sputter negative ion source generates a beam of carbon ions which is pre-separated with a Wien filter and is transported to the cyclotron via a series of electrostatic lenses. Beam is injected radially into the cyclotron using electrostatic deflectors and an electrostatic mirror. Axial focusing is entirely electrostatic. A microchannel plate detector is used with a phase-grated output. In its present form the system is capable of improving the sensitivity of detecting {sup 14}C in some biomedical experiments by a factor of 10{sup 4}. Modifications are discussed which could bring about an additional factor of 100 in sensitivity, which is important for archaeological and geological applications. Possibilities for measurements of other isotopes, such as {sup 3}H, and {sup 10}Be, and {sup 26}Al, are discussed. 70 refs.
Date: November 1, 1989
Creator: Bertsche, Kirk Joseph
Partner: UNT Libraries Government Documents Department

Vibrational state-resolved differential cross sections for the D + H sub 2 yields DH + H reaction

Description: In this thesis, crossed-molecular-beams studies of the reaction D + H{sub 2} {yields} DH + H at collision energies of 0.53 and 1.01 eV are reported. Chapter 1 provides a survey of important experimental and theoretical studies on the dynamics of the hydrogen exchange reaction. Chapter 2 discusses the development of the excimer-laser photolysis D atom beam source that was used in these studies and preliminary experiments on the D + H{sub 2} reaction. In Chapter 3, the differential cross section measurements are presented and compared to recent theoretical predictions. The measured differential cross sections for rotationally excited DH products showed significant deviations from recent quantum scattering calculations, in the first detailed comparison of experimental and theoretical differential cross sections. These results indicate that further work on the H{sub 3} potential energy surface, particularly the bending potential, is in order.
Date: November 1, 1989
Creator: Continetti, Robert Elliot
Partner: UNT Libraries Government Documents Department

Electro-catalytic reduction of nitrogen oxides

Description: Nitrogen oxides have been linked to a broad range of air pollution problems including acid rain and the atmospheric production of photochemical ozone. Over twenty million tons of nitrogen oxides are emitted into the atmosphere each year as a result of the high temperature combustion of fossil fuels. Efforts to control nitrogen oxides emissions have lagged because of the generally low discharge concentrations of nitrogen oxides in combustion exhaust and because nitrogen oxides are more difficult to remove due to their lower reactivity. No catalyst has yet been found that will achieve significant reduction of nitrogen oxides in an oxidizing environment. Oxygen in the exhaust stream competes with nitrogen oxides for the active catalyst sites. Also, the dissociated oxygen atoms produced by decomposition of nitrogen oxides deactivate the surface of the catalyst. Externally applied electric fields have been used to control oxygen adsorption on metal and semi-conductor surfaces. In this investigation, a stream containing nitric oxide has been subjected to intense electric fields in the presence of catalyst materials including steel, stainless steel, and gold plated stainless steel wools and glass wool. The electric fields have been generated using DC, AC and rectified AC potentials in the range of 0--20 KV. The effect of parameters such as inlet nitric oxide concentration, oxygen and water content, gas residence time and temperature have also been studied.
Date: December 1, 1989
Creator: McLarnon, C. R.
Partner: UNT Libraries Government Documents Department

The central drift chamber for the D0 experiment: Design, construction and test

Description: A cylindrical drift chamber has been designed and built at the State University of New York at Stony Brook. This chamber is to be installed in the D0 detector which is being completed at the Fermi National Accelerator. In this dissertation the design, construction and testing of this chamber are described. The characteristic features of this chamber are cells formed by solid walls and a modular structure. Much discussion is given to the performance of and results from a chamber made from three final modules which was installed in the D0 interaction region during the 1988/1989 collider run. Using this chamber proton anti-proton interactions were measured at the D0 interaction point.
Date: August 1, 1989
Creator: Behnke, T.
Partner: UNT Libraries Government Documents Department

Nuclear fuel element

Description: A nuclear fuel element and a method of manufacturing the element. The fuel element is comprised of a metal primary container and a fuel pellet which is located inside it and which is often fragmented. The primary container is subjected to elevated pressure and temperature to deform the container such that the container conforms to the fuel pellet, that is, such that the container is in substantial contact with the surface of the pellet. This conformance eliminates clearances which permit rubbing together of fuel pellet fragments and rubbing of fuel pellet fragments against the container, thus reducing the amount of dust inside the fuel container and the amount of dust which may escape in the event of container breach. Also, as a result of the inventive method, fuel pellet fragments tend to adhere to one another to form a coherent non-fragmented mass: this reduces the tendency of a fragment to pierce the container in the event of impact. 1 fig., 1 tab.
Date: April 6, 1989
Creator: Zocher, R.W.
Partner: UNT Libraries Government Documents Department

Thermionic converter emitter support arrangement

Description: This document discusses a support provided for use in a thermionic converter to support an end of an emitter to keep it out of contact with a surrounding collector while allowing the emitter end to move axially as its temperature changes. The emitter end is supported by a spring structure that includes a pair of Belleville springs, and the spring structure is supported by a support structure fixed to the housing that includes the collector. The support structure is in the form of a sandwich with a small metal spring-engaging element at the front end, a larger metal main support at the rear end that is attached to the housing, and with a ceramic layer between them that is bonded by hot isostatic pressing to the metal element and metal main support. The spring structure can include a loose wafer captured between the Belleville springs. 7 figs.
Date: July 6, 1989
Creator: Allen, D.T.
Partner: UNT Libraries Government Documents Department

Toward a New Generation of Student Outcome Measures: Connecticut's Common Core of Learning Assessment

Description: A report, "Toward a New Generation of Student Outcome Measures: Connecticut's Common Core of Learning Assessment" by Joan Boykoff Baron, Pascal D. Forgione, Jr. Douglas A. Rindone, Hanna Kruglanksi and Bruce Davey. Connecticut State, Department of Education, Division of Research, Evaluation and Assessment. 165 Capitol Avenue - Room 340. Hartford, Connecticut. Presented at American Education Association Annual Meeting, San Francisco, California. Part of Symposium 28.01 Beyond Effective Schools: Quality Indicators for Evaluation Schools and Districts. The Connecticut State Department of Education (CSDE) has begun a multi-year assessment of the extent to which students in Connecticut display the knowledge and traits described in the Common Core of Learning (CCL). Science and mathematics were the two chosen subjects to be assessed under CCL.
Date: March 29, 1989
Creator: Baron, Joan Boykoff; Forgione, Pascal D., Jr.; Rindone, Douglas A.; Kruglanksi, Hannah & Davey, Bruce
Partner: UNT Libraries Special Collections

The Indiana Fine Arts Diagnostic Achievement Tests

Description: A document on the Indiana Fine Arts Diagnostic Achievement Tests, The Getty Center for Education in the Arts Student Assessment Meeting. The Indiana Fine Arts Diagnostic Achievement Testing program began in 1987 as a means to provide art teachers with new tools from which to measure student achievement in visual arts, music, theatre/creative drama and dance/creative movement. The purpose of the testing program is also to create / develop new tools to diagnose student and class strengths or needs.
Date: [1989-11-04,1989-11-06]
Creator: Patchen, Jeffrey H.
Partner: UNT Libraries Special Collections

The Triumph of American Culture Over The Art Education Establishment: Findings from the U.S. National Assessment of Educational Progress in Art

Description: A thesis on, The Triumph of American Culture Over The Art Education Establishment: Findings from the U.S. National Assessment of Education Progress in Art by Brent Wilson. The article is in regards to the United States tasks of assessing educational progress in art. The National Assessment project, they have chosen to assess which school art educational programs have been effective, if the student responds to works of art, values art as an important human experience, know the history of art and can make reasoned judgement on quality of art work.
Date: [1989..]
Creator: Wilson, Brent
Partner: UNT Libraries Special Collections

An Introduction to Arts Propel

Description: A statement on Arts Propel, a cooperative research project concerned with arts and humanities education in junior and high school levels. The statement details how Arts Propel was founded, what they aim to accomplish, the tools and methods they've developed, and why and how art and art education is an important assessment for children.
Date: [1989..]
Creator: Arts Propel Project
Partner: UNT Libraries Special Collections

Two-Dimensional Gel Electrophoresis of in Vivo and in Vitro Synthesized Proteins, Antigenic Proteins, and Cross-Reactive Antigens in Treponema Pallidum Subsp. Pallidum Nichols Strain and Treponema Phagedenis Biotype Reiter

Description: Two-dimensional electrophoretic protein profiles of in vivo and in vitro propagated T.pallidum subsps. pallidum Nichols strain were analyzed and compared. This comparative analysis revealed two in vitro synthesized, cytoplasmic cylinder-associated polypeptides with molecular masses 29.5 and 34.7 kDa, pI 5.62, and one in vitro "lost" polypeptide with molecular mass 34.7 kDa, pI 5.34. integral membrane proteins of in vitro and in vivo propagated T. pallidum was identified by phase partitioning with the nonionic Triton X-114, and twelve outer membrane-associated, antigenic proteins were identified in western blots probed with pooled human secondary syphilitic sera. The solubilization of the outer membrane of T. pallidum with Triton X-114 were monitored by electron microscopy. Treatment of freshly harvested 35S labeled T. pallidum with 1% Triton X-114 resulted in solubilization of the outer membrane and reduction of the diameter of the treponemes from .14 +/- .02 micrometers to .095 +/- .003 micrometers. Examination of thin sections of untreated organisms showed integrity of outer and cytoplasmic membranes. In contrast, thin sections of Triton X-114-treated trponemes showed integrity of the cytoplasmic membrane but the loss of the outer membrane. The cytoplasmic cylinders generated by detergent treatment retained their periplasmic flagella, as judged by electron microscopy and immunoblotting. Integral membrane proteins of Treponema phagedenis were also identified by phase partitioning with Triton X-114, and sizteen cross-reactive, outer membrane-associated, outer membrane-associated, antigenic polypeptides were identified in western blots probed with pooled human secondary syphilitic sera. The results of this study indicate that tow-dimensional protein profiles of in vivo and in vitro propagated T.pallidum are almost identical except for the differences mentioned. This results also indicate that 1% Triton X-114 selectively solubilizes the outer membrane, and the antigenic hydrophobic proteins present in the detergent phrase are located exclusively in the outer membrane.
Date: May 1989
Creator: Sayahtaheri, Sousan
Partner: UNT Libraries

An Investigation of Differences in Public Library Usage Patterns Between Gifted Adults and Members of the General Public

Description: The purpose of this research was to isolate the variable giftedness in a pipulation and determine whether that variable could be used as a predictor of public library use. The analysis of data indicated that public library use was higher for the general public than for the gifted adults. There was less variation among the factors of age, level of education, and public library use for the gifted adults than for the general public. Books as a resource for information were mentioned by the general adults public more frequently than by the gifted adults. Friends were listed more often as an information resource by the gifted population than by the public. Gifted adults both read and owned more books than did the general public. There was no correlation between amount of reading and number of library visits in either sample. 35 of the general public has a Library Usage Index Value of less than 4, 97 of the gifted adults did. There was almost no difference between the first ten information sources listen by both samples.
Date: December 1989
Creator: Foudray, Rita Catherine Schoch
Partner: UNT Libraries

Interrelational Laboratory Information System for Data Storage and Retrieval

Description: The necessity for a functional user friendly laboratory data management program has become evident as the quantity of information required for modern scientific research has increased to to titanic proportions. The required union of strong computer power, ease of operation, and adaptability have until recently been outside the realm of most research laboratories. Previous systems, in addition to their high cost, are necessarily complex and require software experts in order to effect any changes that the end user might deem necessary. This study examines the Apple Macintosh computer program Hypercard as an interactive laboratory information system that is user-friendly, cost effective, and adaptable to the changing demands within a modern molecular or microbiology.
Date: August 1989
Creator: Gregory, Michael W. (Michael Walter)
Partner: UNT Libraries

The Relationship of Receiving Violence and Perceptions of Self and Partner

Description: The purpose of the present study was to determine whether there are any differences between college students 1) who have received violence 2) who have received threats of physical violence, and 3) who have not received threats or physical violence from their partners. The study examined ways in which these three groups describe their own and their partners' self-esteem and personality. Significant findings indicate that perceptions of one's self esteem and partner's self esteem are affected by the level of violence received. Surprisingly, those who received threats of violence, for both perceptions of self and partners, had the lowest self esteem. No significant relationship was found between vilence and perceptions of personality. Additional findings suggest that those in violent relationships have lower relationship satisfaction that those who receive threats or no violence at all.
Date: August 1989
Creator: Quest, Kathryn
Partner: UNT Libraries

Jet Production in the Central Rapidity Region in 1.8 TeV Proton and Antiproton Collisions

Description: In this thesis we study the jet production cross section in the central rapidity region in {bar p}p collisions at a center of mass energy of 1.8 TeV. The pseudo-rapidity {eta} is defined as {eta} {triple_bond} -ln(tan({theta}/2)), where {theta} is the angle between the directions of the jet momentum and the proton beam. We will call the region -0.7 < {eta} < 0.7 the 'central rapidity' region by definition. The goal of this thesis is to determine two kinds of differential cross sections for jet production: an inclusive jet Et distribution d{sigma}/dEt, and the distribution in invariant mass d{sigma}/dM{sub JJ} of two jet systems. These spectra serve to check the strong interaction theory, and thus to look for new phenomena, at the highest available energy. The strong interaction theory will be discussed.
Date: June 1, 1989
Creator: Tsai, Yeong-Dong & U., /Chicago
Partner: UNT Libraries Government Documents Department

Estimating nonpoint source pollution in north Texas watersheds through remote sensing and geographic information systems

Description: Monitoring nonpoint source pollution in a large area is often impractical. However, estimating nonpoint pollution through use of empirical models such as the Universal Soil Loss Equation (USLE) provides a basis for identifying problem areas, and setting management priorities. The purpose of this study was to determine the feasibility of using Landsat imagery and existing geographic data to estimate the effects of land use changes on water quality in four North Texas watersheds over a twelve year period.
Date: December 1989
Creator: Groome, Kristina M. (Kristina Martin)
Partner: UNT Libraries

Localization of serotonin (5-hydroxytryptamine, 5-HT) with partial purification and characterization of a serotonin binding protein in the intestinal tissue of the nematode Ascaris suum

Description: Muscle, hypodermis and gastrointestinal epithelium from adult female Ascaris lumricoides var. summ were found to contain serotonin based upon glyoxylic acid induced histofluorescence and indirect immunolabeling with an anti-serotonin monoclonal antibody conjugated to protein A-colloidal gold.
Date: May 1989
Creator: Martin, Rex E. (Rex Edward)
Partner: UNT Libraries

Applications of GIS and remote sensing for the characterization of habitat for threatened and endangered species

Description: Geographic Information Systems (GIS) and remote sensing technologies were used to identify and describe potential habitat for three species endemic to the Southwestern United States; the Golden-cheeked Warbler (Dendroica chrysoparia), the Black-capped Vireo (Vireo atricapillus), and the Texas kangaroo rat (Dipodomys elator). For each species, the computerized classification of digital satellite imagery was integrated with ancillary spatial information (e.g. soils, geology, and land use) to construct a data base to be used for ecological evaluation as well as habitat protection and management measures.
Date: December 1989
Creator: Shaw, Denice Marie
Partner: UNT Libraries