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Low temperature heat capacity of lutetium and lutetium hydrogen alloys
The heat capacity of high purity electrotransport refined lutetium was measured between 1 and 20/sup 0/K. Results for theta/sub D/ were in excellent agreement with theta values determined from elastic constant measurements. The heat capacity of a series of lutetium-hydrogen solid solution alloys was determined and results showed an increase in ..gamma.. from 8.2 to about 11.3 mJ/g-atom-K/sup 2/ for hydrogen content increasing from zero to about one atomic percent. Above one percent hydrogen ..gamma.. decreased with increasing hydrogen contents. The C/T data showed an increase with temperature decreasing below about 2.5/sup 0/K for samples with 0.1 to 1.5 atomic percent hydrogen. This accounts for a large amount of scatter in theta/sub D/ versus hydrogen content in this range. The heat capacity of a bulk sample of lutetium dihydride was measured between 1 and 20/sup 0/K and showed a large increase in theta/sub D/ and a large decrease in ..gamma.. compared to pure lutetium.
Date:
October 1, 1977
Creator:
Thome, D. K.
System:
The UNT Digital Library
Polariton effects in naphthalene crystals
The experimental verification of the two-step nature of energy dissipation of photon energy by a crystal is the subject of this dissertation. The ..cap alpha..(O,O) Davydov component of the lowest energy singlet transition in pure strain-free napthalene single crystals is shown to exhibit an increase in absorption with increasing temperature, due to an increase in polariton damping via polariton-phonon scattering processes. (GHT)
Date:
October 1, 1977
Creator:
Robinette, S. L.
System:
The UNT Digital Library
Synthesis and characterization of an N-(2-hydroxyethyl)-ethylenediaminetriacetic acid resin
A chelating ion-exchange resin with N-(2-hydroxyethyl)ethylene-diaminetriacetic acid (HEDTA) used as the ligand chemically bonded to XAD-4 by an ester linkage, HEDTA-4, was synthesized. It is stable under normal experimental conditions with the liquid chromatograph. The structure of the resin was confirmed by an infrared spectrum, and by potentiometric titrations. The capacity of the resin was also obtained by potentiometric titration and by a nitrogen analysis. The resin was used to pack a column of 5 mm internal diameter and 5 cm long. The effect of pH on the retention of different metal ions on the resin was studied. It was found that the resin was most selective for chromium(III), copper(II), lead(II), mercury(II), uranium(VI), zirconium(IV) and zinc(II) at a pH of less than 3. Furthermore, the resin proves to be functioning with a chelating mechanism rather than ion-exchange, and it can concentrate trace metal ions in the presence of a large excess of calcium and magnesium. This makes the resin potentially useful for purifying and analyzing drinking water.
Date:
October 1, 1977
Creator:
Lai, Y. F.
System:
The UNT Digital Library
Electron microscopy of hydrocarbon production in parthenium argentatum (guayule)
The electron microscope was used to study the biological processes involved in hydrocarbon production. The little desert shrub Guayule (Parthenium argentatum) was selected for study. This shrub can produce hydrocarbons (rubber) in concentrations up to 1/4 of its dry weight. It grows on semi-arid land and has been extensively studied. The potential of Guayule is described in detail. Results of an investigation into the morphology of Guayule at the electron microscope level are given. Experiments, which would allow the biosynthesis of hydrocarbon in Guayule to be followed, were designed. In order to do this, knowledge of the biochemistry of rubber formation was used to select a tracer, mevalonic acid. Mevalonic acid is the precursor of all the terpenoids, a large class of hydrocarbons which includes rubber. It was found that when high enough concentrations of mevalonic acid are administered to seedling Guayule plants, build-ups of metabolized products are found within the chloroplasts of the seedlings. Also, tritium labeled mevalonic acid was used as a precursor, and its metabolic progress was followed by using the technique of electron microscope autoradiography. The results of these experiments also implicated chloroplasts of the Guayule plant in hydrocarbon production. The final task was the development …
Date:
November 1, 1977
Creator:
Bauer, T.E.
System:
The UNT Digital Library
Stress induced reorientation of vanadium hydride
The critical stress for the reorientation of vanadium hydride was determined for the temperature range 180/sup 0/ to 280/sup 0/K using flat tensile samples containing 50 to 500 ppM hydrogen by weight. The critical stress was observed to vary from a half to a third of the macroscopic yield stress of pure vanadium over the temperature range. The vanadium hydride could not be stress induced to precipitate above its stress-free precipitation temperature by uniaxial tensile stresses or triaxial tensile stresses induced by a notch.
Date:
October 1, 1977
Creator:
Beardsley, M. B.
System:
The UNT Digital Library
Electromigration of hydrogen and deuterium in vanadium, niobium, and tantalum
The electric mobility and effective valence of hydrogen and deuterium in vanadium, niobium, tantalum and three niobium-tantalum alloys were measured. A resistance technique was used to directly determine the electric mobility of hydrogen and deuterium at 30/sup 0/C while a steady-state method was used to measure the effective valence. The use of mass spectrographic techniques on a single specimen which contained both hydrogen and deuterium greatly increased the precision with which the isotope effect in the effective valence could be measured.
Date:
October 1, 1977
Creator:
Jensen, C. L.
System:
The UNT Digital Library
Use of a semiconductor laser in infrared spectroscopy
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 collimated over large distances with minimal optical losses and be easily detected. One can rapidly measure the decrease in transmission of the light due to the absorption of the light by the gas being monitored, and, using certain analytical parameters, which are different for each absorption line, one can determine the concentration of the gas in question immediately. In addition to the line center (nu/sub 0/), these analytical parameters are the intensity (S) and the half width at half maximum (..gamma..). The intensity (S) is dependent only on temperature when expressed in a per concentration basis and ..gamma.. is dependent on pressure. The Lorentzian lineshape equation K(nu) + S/..pi gamma..(((nu - nu/sub 0/)/..gamma..)/sup 2/ + 1)/sup -1/ is the equation …
Date:
December 1, 1977
Creator:
Morris, R. N.
System:
The UNT Digital Library
Inductively coupled plasma--atomic emission spectrometry: trace elements in oil matrices
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 elements studied ranged from 0.0006 to 9 ..mu..g/g with the majority falling in the 0.01 to 0.1 ..mu..g/g range. Analytical calibration curves were linear over at least two orders of magnitude and for some elements this linearity extended over 4.5 orders of magnitude. Relevant data on precision and accuracy are included. Because metals often occur as particles in lubricating oil and coal liquefaction products, the effect of particles on the analytical results was examined. Wear metal particles in used oil did not appear to affect the analytical results. However, incomplete recovery relative to organometallic reference solutions was obtained for iron particles with a nominal mean diameter of 3.0 ..mu..m suspended in oil. It was shown that the following factors contributed to incomplete recovery for the particles: settling of the …
Date:
December 1, 1977
Creator:
Peterson, C. A.
System:
The UNT Digital Library
Analytical applications of resins containing amide and polyamine functional groups
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.
System:
The UNT Digital Library
Dislocation morphology in deformed and irradiated niobium. [Neutron irradiation]
Niobium foils of moderate purity were examined for the morphology of dislocations or defect clusters in the deformed or neutron-irradiated state by transmission electron microscopy. New evidence has been found for the dissociation of screw dislocations into partials on the (211) slip plane according to the Crussard mechanism: (a/2) (111) ..-->.. (a/3) (111) + (a/6) (111).
Date:
June 1, 1977
Creator:
Chang, C. P.
System:
The UNT Digital Library
Lanthanide extraction with 2,5-dimethyl-2-hydroxyhexanoic acid
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 complexes with the DMHHA anions. The extracted metal species is highly aggregated. This extraction has a solubility limit which increases with the addition of unionized acid. The resultant extract is also highly aggregated. At unionized acid-to-metal ratios greater than one, extractions first occur followed by the slow precipitation of the lanthanide. At the tracer level, neodymium is extracted primarily as NdA/sub 3/(HA)/sub 5/ and (NdA/sub 3/)/sub 2/(HA)/sub q/. Very small amounts of (NdA/sub 3/)/sub 2/ and other metal aggregates are also present. The heavy lanthanides do not extract from solutions of DMHHA and its potassium salt, but form aqueous emulsions and precipitates. In the presence of the organic soluble tetrabutylammonium ion the heavy lanthanides can be extracted, presumably as ion pairs. The stability constants of the …
Date:
December 1, 1977
Creator:
Miller, J. H.
System:
The UNT Digital Library
Investigation of high energy runaway electron confinement in the Oak Ridge tokamak
High energy runaway electrons in the Oak Ridge tokamak ORMAK have been investigated through measurement of the bremsstrahlung produced when these electrons leave the discharge and strike the limiting aperture of the torus. The experimental results have been interpreted in terms of a classical single-particle model appropriate for collisionless particles in a tokamak, and it has been found that most of the confinement properties of high energy runaways in ORMAK can be understood on this basis. An experiment designed to directly test this model has disclosed an anomalous transport which has been described by a runaway diffusion coefficient D approximately 10/sup 2/ to 10/sup 4/ cm/sup 2//sec appropriate for runaways near the outside of the plasma. A discussion of the possible mechanisms for this anomalous transport is given.
Date:
November 1, 1977
Creator:
Zweben, S. J.
System:
The UNT Digital Library
Heated uranium tetrafluoride target system to release non-rare gas fission products for the TRISTAN isotope separator. [As replacement for uranyl stearate]
Off-line experiments indicated that fluorides of As, Se, Br, Kr, Zr, Nb, Mo, Tc, Ru, Sb, Te, I and Xe could be volatilized, but except for Br, Kr, I and Xe, none of these elements were observed after mass separation in the on-line experiments. The results of the on-line experiments indicated a very low level of hydride contamination at ambient temperature and consequently, uranium tetrafluoride replaced uranyl stearate as the primary gaseous fission product target. Possible reasons for the failure of the heated target system to yield non-rare gas activities are discussed and suggestions for designing a new heated target system are presented.
Date:
October 1, 1977
Creator:
Gill, R. L.
System:
The UNT Digital Library
Evaluation of self-interaction parameters from binary phase diagrams
The feasibility of calculating Wagner self-interaction parameters from binary phase diagrams was examined. The self-interaction parameters of 22 non-ferrous liquid solutions were calculated utilizing an equation based on the equality of the chemical potentials of a component in two equilibrium phases. Utilization of the equation requires the evaluation of the first and second derivatives of various liquidus and solidus data at infinite dilution of the solute component. Several numerical methods for evaluating the derivatives of tabular data were examined. A method involving power series curve fitting and subsequent differentiation of the power series was found to be the most suitable for the interaction parameter calculations. Comparison of the calculated self-interaction parameters with values obtained from thermodynamic measurements indicates that the Wagner self-interaction parameter can be successfully calculated from binary phase diagrams.
Date:
October 1, 1977
Creator:
Ellison, T. L.
System:
The UNT Digital Library
Multiconfigurational electronic wavefunctions in the full optimized reaction space: the isomerization of nitrosyl hydride to nitrogen hydroxide in the lowest singlet and triplet states
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 out using a novel configuration interaction approach called the Full Optimized Reaction Space method, which involves multiconfigurational self-consistent field calculations as an integral part. In order to interpret the bonding changes occurring during the reaction, a novel type of orbital is developed and calculated. These are called Directed Localized Reaction Orbitals. With their help it proves possible to give an interpretation of the isomerization in terms of concepts which fit chemical intuition.
Date:
December 1, 1977
Creator:
Dombek, M. G.
System:
The UNT Digital Library
Electronic transitions of some pi-molecular charge transfer complexes. [Anthracene--pyromellitic dianhydride (PMDA) or pyrene--PMDA in naphthalene--PMDA host]
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-acceptor stretch. The unusual reduction of the phonon mode frequency in the excited ground state is explained in terms of a contracted complex that can more easily rotate in a larger cavity. A brief phonon progression is also observed for the mixed crystal A-PMDA in N-PMDA. For both mixed crystals, Py-PMDA in N-PMDA and A-PMDA in N-PMDA, the energy spacing between the zero-phonon vibrational bands in the mixed CT crystal phosphorescence spectrum are very similar to those obtained from the phosphorescence spectrum of the pure donor in a rigid matrix. There is a large blue shift between the origin band of the mixed CT crystal phosphorescence spectrum and the origin band of the pure donor phosphorescence spectrum for the A-PMDA mixed crystal, but not for the Py-PMDA mixed crystal. The structureless …
Date:
December 1, 1977
Creator:
Beckman, R. L.
System:
The UNT Digital Library
Piano Sonata by Elliott Carter: A Foreshadowing of His Later Style, a Lecture Recital, Together with Three Recitals of Selected Works
The lecture recital was given January 22, 1977. A discussion of Elliott Carter's Piano Sonata emphasized those compositional techniques which foreshadowed important compositional procedures in many of his later works. The following compositions were discussed: Concerto for Orchestra, Double Concerto for Harpsichord and Piano with Two Chamber Orchestras, 8 Etudes and a Fantasy for Woodwind Quartet, Holiday Overture, Piano Concerto, Sonata for Flute, Oboe, Cello, and Harpsichord, Sonata for Violoncello and Piano, String Quartet No. 1, String Quartet No. 2, String Quartet No. 3, Variations for Orchestra. The Piano Sonata was Ty and Schumann. In addition to the lecture recital, three public solo recitals were performed. The first solo recital, performed on April 2, 1973, consisted of works by Bartok, Debussy The second solo recital, performed on October 28, 1974, included works by Bach and Liszt. The final solo recital, performed on March 7, 1976, consisted of works by Beethoven and Chopin. All four programs were recorded on magnetic tape and are filed, along with the written version of the lecture recital, as part of the dissertation. performed.
Date:
May 1977
Creator:
Wilhite, Carmen Irene
System:
The UNT Digital Library
A Survey of the Use of Computers at State-Supported Senior Colleges and Universities in the United States
The purpose of this study was to determine the use of the computer in higher education at state-supported senior colleges and universities in the United States. The following findings and conclusions are based on the information gained from the study. 1. The average number of years computers have been used by institutions of higher education is ten. The length of time increases with both the level of offering and the enrollment of the institution. 2. A greater emphasis is placed on administrative use of the computer than on other uses. 3. A majority of the institutions have one centralized computer center that provides services to all users. Also, the majority of the individual computer users are provided the services without explicit charges or are only charged for a part of the services. 4. Policies pertaining to the use of the computer are most frequently formulated by the director of the computer center and a computer usage committee. 5. The amount of money spent for each of the different categories for expenditures (administrative, academic, and research) increases with the level of offering of the institutions. 6. Sixty-eight per cent of the institutions now offer an academic program in computer science and …
Date:
May 1977
Creator:
Anderson, John W., 1944-
System:
The UNT Digital Library
Early English Organ Music: Some Contributions from the Mulliner Book of W. Blitheman, T. Tallis and J. Taverner: Together with Three Recitals of Selected Works of J. S. Bach, D. Buxtehude, M. Duruflé, C. Franck, G. Frescobaldi, J. J. Frogerber, P. Hindemith, O. Messiaen, M. Reger, J. H. Tallis, and C.-M. Widor
The lecture recital was given April 16, 1971. An Excellent Meane, six settings of Gloria Tibi Trinitas, Eterne rerum conditor, and Te Deum laudamus by William Blitheman, In Nomine by John Taverner, and Ecce tempus idonem by Thomas Tallis were performed, together with a choir of four men's voices, following a lecture on various aspects of organ music in early Tudor England. In addition to the lecture recital, three other public recitals, all solo programs, were performed. The first solo recital, including works of Dietrich Buxtehude, Johann Sebastian Bach, Paul Hindemith, and Max Reger, was performed on March 14, 1971. On October 23, 1972, the second solo recital was performed. The program included compositions by Olivier Messiaen, Johann Sebastian Bach, Cesar Franck, and Charles-Marie Widor. On October 17, 1977, the third solo recital, including works by Johann Sebastian Bach, Girolamo Frescobaldi, Johann Jacob Froberger, Dietrich Buxtehude, James Hathaway Tallis, and Maurice Durufle, was performed. The four programs were recorded on magnetic tape and are filed with the written version of the lecture as a part of the dissertation.
Date:
December 1977
Creator:
Lowry, David Michael
System:
The UNT Digital Library
The Effects of a Systematic Training Program in Responding Skills on Dental Hygiene Students at Texas Woman's University
The purposes of this investigation were (1) to determine if a systematic training program in communication skills could be used to improve written response levels of dental hygiene students, and (2) to determine if a systematic training program in communication skills could yield improved dental hygiene student-patient rapport. The experiment involved two groups of dental hygiene students that had previously been randomly selected and consisted of twelve junior and twelve senior students in each group. The entire population of dental hygiene students at Texas Woman's University participated in the study. Analysis of the data provided statistically significant findings on seven of the eight hypotheses. Those subjects in the systematic training program were able to demonstrate increased ability to write responses and, in addition, had higher patient rapport scores. The results were also statistically significant two weeks following the training period. It was, therefore, concluded that the systematic training program in communication skills was an effective teaching device for improving dental hygiene responses. The systematic training program also seemed to be an effective strategy for improving dental hygiene student-patient rapport formation.
Date:
May 1977
Creator:
Wallace, David W.
System:
The UNT Digital Library
Financial Leverage and the Cost of Capital
The objective of the research reported in this dissertation is to conduct an empirical test of the hypothesis that, excluding income tax effects, the cost of capital to a firm is independent of the degree of financial leverage employed by the firm. This hypothesis, set forth by Franco Modigliani and Merton Miller in 1958, represents a challenge to the traditional view on the subject, a challenge which carries implications of considerable importance in the field of finance. The challenge has led to a lengthy controversy which can ultimately be resolved only by subjecting the hypothesis to empirical test. The basis of the test was Modigliani and Miller's Proposition II, a corollary of their fundamental hypothesis. Proposition II, in effect, states that equity investors fully discount any increase in risk due to financial leverage so that there is no possibility for the firm to reduce its cost of capital by employing financial leverage. The results of the research reported in this dissertation do not support that contention. The study indicates that, if equity investors require any increase in premium for increasing financial leverage, the premium required is significantly less than that predicted by the Modigliani-Miller Proposition II, over the range of …
Date:
December 1977
Creator:
Brust, Melvin F.
System:
The UNT Digital Library
Perceived Effect of the Quarter System on the Programs of Selected Middle Schools in the State of Texas
The problem of this study was to analyze the effect that a legislature-mandated quarter system was having on certain selected middle schools in the State of Texas, Some educators have claimed that the quarter system makes it possible to add flexibility to school programs. This study, therefore, was an attempt to find out if local school districts were taking advantage of this opportunity. A second goal of the study was to determine how principals, teachers, and curriculum directors felt about the manner in which schools were implementing certain teaching strategies which experts in this field have recommended for use in middle schools. It was concluded that the schools were not taking advantage of the quarter system in order to more nearly approach the middle school concept. Educators do not seem to be against the innovations proposed by middle school authorities so it would seem that the time is right for a full commitment to the area of schooling for the middle years. The support of the general public then will be a key factor in the success of the middle school. Educators must make an effort to keep the public better informed about the way children learn and grow if …
Date:
August 1977
Creator:
Acuff, George D.
System:
The UNT Digital Library
An Examination of the Hawthorne Effect in a Verbal Learning Situation in an Educational Setting
This study was an examination of the Hawthorne Effect in a verbal learning situation in an educational setting. The Hawthorne Effect was defined as the facilitating effect(s) produced in experimental situations when the subjects of the experiment expect that they are the objects of special attention. The purpose of the study was to determine if contamination by the Hawthorne Effect existed in an educational setting. Comparisons were made between "experimentally inexperienced" subjects and "experimentally experienced" subjects at both undergraduate and graduate levels. The task was to learn a list of paired associate terms, and to show learning retention by immediate replication of those terms. The focus of the study was upon the expected differences in performance of the control and experimental groups produced as a result of an effort to persuade experimental subjects that they had "unique" characteristics which would cause them to be exceptionally proficient. The control groups were given the task by the course instructor in a usual classroom setting,as an example of a curriculum objective. Recommendations for further research were as follows: (1) the personality variables of the researcher and those of the subjects being tested should be thoroughly delineated; (2) sex differences in performance should be …
Date:
December 1977
Creator:
Simpson, Bert L.
System:
The UNT Digital Library
Corporate Planning and Forecasting: An Analysis of the State of the Art in the Service Industry and Development of a Generalized Approach for the Needs of the 1970's and the 1980's
This study has a twofold purpose. The first is to demonstrate the state of the art of corporate planning and forecasting activity, and the second is to determine the existence of any differences between the planning practices of the consumer service industry and the producer service industry. The study is organized into seven chapters. The introduction chapter contains background information, a description of the problem and opportunity followed by a definition of terms, the purpose of the research, hypothesis of the research. It also describes the scope of the research, methodology, significance and limitations of the study and provides a chapter bibliography. The study finds that though certain segments of the service industry have sophisticated planning capability, it is not generally widespread. The study concludes there is no significant difference in the planning methods between consumer services and producer services industries
Date:
May 1977
Creator:
Subramanian, Bala R.
System:
The UNT Digital Library