Physical Sciences and Mathematics Commons^™

Determination Of Phenomenological Optical Model Parameters For Neutrons On 208Pb From 4 To 150 Mev, Randy L. Schutt

Masters Theses

Phenomenological o p tic a l model parameters for neutrons incident on ²⁰⁸Pb have been determined for neutron energies from 4 to 150 MeV using the code SNOOPY-8. Neutron total cross sections from 4 to 150 MeV and angular distributions for elastic scattering from 13.5 to 40.0 MeV were utilized. Analyses of total and differential cross sections were performed at a number of energies to determine energy dependent expressions for the real strengths of the central potential, imaginary surface potential, and imaginary volume potential. These energy dependent expressions for V, W_d, and W_S were found to …

Experiment Module For Microprocessor Based Data Acquisition And Speech Processing, Namazi Bin Azhari

Masters Theses

This project involves microprocessor applications to the acquisition of physical data. The experiment module developed here will help the physics teacher and the scientist demonstrate the uses and advantages of digital techniques to students. Specific examples of data acquisition and processing are illustrated using speech and repetitive waveforms. The project centers on a module that is programmed to perform a number of types of data recordings and processings.

A Study Of Classical Elastic Scattering For Heavy-Ion Nuclear Reactions, John C. Orrison

Masters Theses

Numerical computer programs were developed to calculate the classical elastic scattering orbits, deflection functions and differential scattering cross-sections for a heavy-ion nuclear reaction model.

Critical points of the deflection functions and differential scattering cross-sections were examined.

Semiclassical modifications were developed for future study to account for the phase relation between independent orbits that lead to the same scattering direction.

Further Studies On Purification Of A Mannitol Binding Protein: Use Of Ph Gradients For Elution From Cation Exchange Resin, Kristyne Ann Baumgarten

Masters Theses

Studies on the purification of a mannitol binding protein (MBP) from Pseudomonas aeruginosa PAO were performed. Utilizing the alkaline isoelectric point (pi 8.3) of MBP, pH gradients were used to elute MBP from carboxymethylcellulose cation exchange resins. Purification of MBP was monitored by sodium dodecyl sulfate-polyacrylam ide gel electrophoresis (SDS-PAGE). Only one protein band was seen on SDS-PAGE from MBP fractions elutedat pH 7-8 and 8 .2. Although pH gradients appear to give good purification from cation exchange resins, these procedures lead to loss of MBP activity.

Calculations For The Excitation Of High Spin Natural Parity States In Hypernuclei Via (Π+, K+), Yizhang Ho

Masters Theses

No abstract provided.

Microscopic Optical Potentials, Michael R. Sloothaak

Masters Theses

No abstract provided.

Medium Modified Proton Densities Deduced From Electron Scattering Experiments, Steven Paul Deryke

Masters Theses

Recently two fundamental problems in nuclear physics have been resolved by applying the concept of nucleon size increases over that of free nucleons. These successes have encouraged the use of medium-modified proton densities to explain the differences between Hartree-Fock calculations and experimental charge densities. These differences constituted a long standing problem in nuclear physics.

The covariant soliton model of density dependent nucleon form factors was employed to explain these differences. This model predicts a non-linear relationship between point proton densities and charge densities. This work was able to provide a self-consistent proton density for ²⁰⁸Pb by inverting this relationship. …

Effect Of Strain On Muon Diffusion And Trapping In Metal By Bassam Salim Hitti, Bassam Salim Hitti

Dissertations, Theses, and Masters Projects

Positive muons implanted in metal distort the surrounding lattice; therefore, in addition to electronic interactions, the elastic forces have to be considered in determining the muon state. to explore the elastic and electronic diffusion and trapping mechanisms, we studied AlCu(,420ppm), AlMg(,1000ppm) and AlAg(,1000ppm) alloys. These alloys were selected for the different effects on the host lattice of these impurities; Cu contracts the Al lattice, Mg expands it and Ag has nearly no effect. On the other hand Cu and Ag are monovalent while Mg is divalent. For AlCu between 5K and 14K the temperature exponent (beta) of the two-state-model trapping …

Low-Energy Collisions Of Alkali-Metal Anions, David M. Scott

Dissertations, Theses, and Masters Projects

Measurements of the total cross section for electron detachment, (sigma)(,e)(E), are presented for low-energy (E(,1ab) < 300 eV) collisions of Na('-), K('-), and Cs('-) with atomic and molecular targets. For many of the atomic (rare-gas) targets, the energy dependence of (sigma)(,e)(E) is striking: virtually no detachment is observed until relatively high collision energies (50 eV in the center-of-mass frame) are reached, in contradistinction to what has been observed for similar collisions involving H('-). The thresholds for alkali anion detachment are approximately equal to the thresholds for excitation observed in collisions of neutral alkali atoms with these same targets. The similarity between the dynamics of the neutral system and that of the negative ion system, together with the observation (at greater energies) of detachment accompanied by excitation of the alkali parent, suggests that electron detachment may be mediated by a two-electron process in some cases. A simple curve-crossing mechanism adequately reproduces the observed (sigma)(,e)(E) for several of these rare-gas targets.;Measurements of both (sigma)(,e)(E) and the cross section for charge transfer (sigma)(,i)(E) have also been completed for H(,2), D(,2), N(,2), O(,2), CO, CO(,2), SO(,2), N(,2)O, CH(,4), and SF(,6) targets. Electron detachment is the dominant process for all of these targets except O(,2), SO(,2), and SF(,6), with thresholds on the order of a few eV. Structure in (sigma)(,e)(E) for the CO(,2) target has been attributed to charge transfer to a metastable state of CO(,2)('-)(('2)A(,1)). Similarly, in the case of N(,2)O, both (sigma)(,e)(E) and (sigma)(,i)(E) exhibit behavior which suggests that a temporary negative ion state is formed during the collision. In the case of the O(,2), SO(,2), and SF(,6) targets, charge transfer is observed to have particularly large cross sections (>100 (ANGSTROM)('2)) at low collision energies.

A Nuclear Magnetic Resonance Study Of Deuterated Poly(Vinylidene Fluoride) And A Copolymer Of Deuterated Vinylidene Fluoride And Tetrafluoroethylene, Montee A. Doverspike

Dissertations, Theses, and Masters Projects

Pulsed deuterium NMR experiments have been performed on deuterated samples of poly(vinylidene fluoride), PVF(,2), repeat unit CH(,2)CF(,2) and the copolymer poly(vinylidene fluoride)-tetrafluoroethylene (80-20), (PVF(,2)-F(,4)E). A deuterium line shape study has been employed to characterize the orientational distribution of the dipole moments in both poled and unpoled samples. In addition, the orientational distributions of chain axis alignment has been measured in stretched samples.;PVF(,2) and PVF(,2)-F(,4)E exhibit unique piezoelectric and pyroelectric properties which are due to their crystalline components (approximately 50% in typical material). Four crystalline phases exist in the homopolymer PVF(,2), the (alpha), (beta), (gamma), and the (delta). The relatively electrically …

Determination Of The Vacancy Migration Energy Of Aluminum By Nmr, Terry William Gullion

Dissertations, Theses, and Masters Projects

Monovacancy diffusion is a thermally activated process characterized by an activation energy E(,d). The diffusion of atoms requires the formation and migration of vacancies. The concentration of vacancies n/N is given by n/N (DBLTURN) exp(-E(,f)/kT). It can be shown that the activation energy E(,d) is the sum of the energy to form a vacancy E(,f) and the energy required for an atomic jump E(,m): E(,d) = E(,f) + E(,m). Furthermore, the atomic jump rate (omega)(,j) can be shown to be thermally activated and given by (omega)(,j) (DBLTURN) (nu)(,o)(n/N)exp(-E(,m)/kT) ((nu)(,o) is the attempt frequency).;NMR offers many techniques to measure the activation …

Rydberg Atoms In Parallel Electric And Magnetic Fields, Robert Leonard Waterland

Dissertations, Theses, and Masters Projects

I have calculated the energy spectrum of a highly excited atom which lies in parallel, static electric and magnetic fields. In parallel fields the Coulomb quantum numbers n and m are still "good" quantum numbers but 1 is not: the calculation is for n = 30, m = 1 atoms.;The eigenvalues were obtained by semi-classical quantisation of first-order classical perturbation theory and have been calculated for a large range of electric and magnetic field strengths. The results are in good agreement with those found from first-order degenerate quantum perturbation theory.;The semi-classical analysis provides a correlation diagram connecting the Stark effect …

Structural And Topological Contributions To The Electronic Properties Of Inhomogeneous Media (Fractal, Electrode, Impedance), Michael Kramer

Dissertations, Theses, and Capstone Projects

Recent theoretical developments in the theory of inhomogeneous media have enabled Physicists to explore various properties of random composites. We demonstrate how these techniques can be applied to the treatment of electrochemical systems, specifically porous structures. A Random Network Model is introduced to represent the porous electrode immersed in electrolyte, and using numerical simulation the a.c. impedance behavior of the system is explored. We explore how various compositional and structural parameters contribute to the electrical properties of the system. The topology of our model is analyzed, and the effect of fractal structures on impedance behavior is considered. To examine the …