Digital Commons Network^™

O-Phthalaldehyde Modification Of Sarcoplasmic Reticulum Calcium Release, Steffen Koehler

Dissertations and Theses

Muscle contraction is a phenomena which fascinated already the ancient Greeks. People have long sought to understand the mechanism of muscle contraction. Today we know that in order for muscle to contract, an action potential propagates from the nerve cell to the muscle cell. Upon arriving at the muscle cell, via a mechanism called Excitation- Contraction (E-C) coupling, Ca2 + is released from an intracellular membrane system, the sarcoplasmic reticulum (SR), into the intracellular fluid. The increase of intracellular Ca2 + initiates the interaction between the contractile units which results in force development and tension. The least well understood step …

Electrolysis Of Palladium In Heavy Water, Christoph Zaczek

Dissertations and Theses

Following several reports in the past few years about compositional changes on palladium used as a cathode in heavy water electrolysis, the purpose of this research project was to reproduce this results.

Two experiments were performed using two cells connected in series, an experimental cell and a control cell.

Both experiments used platinum anodes, the experimental cell had a palladium cathode and the control cell had a platinum cathode. The electrolyte was D₂O with H₂SO₄. Radiation was monitored during both experiments. Also temperature and voltage were recorded for both experiments, to allow statements about …

Studies Of Mixing Processes In Gases And Effects On Combustion And Stability, Frank Paul Kozusko Jr.

Mathematics & Statistics Theses & Dissertations

Three physical models of laminar mixing of initially separated gases are studied. Two models study the effects of the mixing dynamics on the chemical reactions between the gases. The third model studies the structure and stability of a laminar mixing layer in a binary gas. The three models are:

1. Two ideal and incompressible gases representing fuel and oxidizer are initially at rest and separated across an infinite linear interface in a two dimensional system. Combustion, expected as the gases mix, will lead to a rapid rise in temperature in a localized area, i.e. ignition. The mixing of the gases …

Nuclear Forward-Scattering Of Synchrotron Radiation From Krypton: First Observation And Application To The Study Of Lattice Dynamics In Near-Monolayer Krypton-On-Graphite, David Eric Johnson

Physics Theses & Dissertations

Since 1985 nuclear-resonant scattering, and in particular nuclear forward-scattering, of synchrotron radiation has been observed in a select few Mossbauer isotopes including: ⁵⁷Fe, ¹¹⁹Sn, ¹⁶⁹Tm. For the first time, nuclear forward-scattering from the 9.4 keV Mossbauer level in ⁸³Kr has been observed. A large resonance effect, comparable to that in ⁵⁷Fe, has been observed in a variety of systems containing Kr including bulk crystals and physisorbed Kr-on-exfoliated graphite. Previous nuclear-resonant scattering experiments using synchrotron radiation have consisted of demonstration experiments. Nuclear forward-scattering from Kr has been applied to study the lattice dynamics of near-monolayer Kr-on-graphite …

The Study Of Pion Absorption On -4he At 355 Mev/C With Lads (Large Acceptance Detector System), Thomas A. Dooling

Physics Theses & Dissertations

The medium and long range part of the nucleon-nucleon interaction can be described within the framework of pion exchange. In order to understand this fundamental interaction, it is therefore important to study the interaction of pions with nucleons and nuclei, which can either be elastic or inelastic scattering or absorption. Whereas the elastic and inelastic channels can be well described by different models, our understanding of pion absorption is still rather poor. There are still a lot of open questions, for instance on the strength of three and more nucleon absorption and the role of initial and final state interactions. …

Ohmic Contact To Ion Implanted Gallium Arsenide Antimonide For Application To Indium Aluminum Arsenide-Gallium Arsenide Antimonide Heterostructure Insulated-Gate Field Effect Transistors, Kenneth G. Merkel Ii

Theses and Dissertations

The p-channel In_0.52Al_0.48As-GaAs_1-xSb_x heterostructure insulated-gate field effect transistor (p-HIGFET) is a candidate for complementary integrated circuits due to superior cutoff characteristics and low gate leakage current. Advancement of the In_0.52Al_0.48As-GaAs_1-xSb_x p-HIGFET requires improved source-drain design. Five main tasks were accomplished to achieve this goal. First, thermal limits of the In_0.52Al_0.48As-GaAs_0.51Sb_0.49 HIGFET were investigated. Second, the temperature dependence of band gap and impurity energies were determined for beryllium doped In_0.52Al_0.48. Third, high acceptor concentrations were obtained …

Electrolysis Of Titanium In Heavy Water, Radovan Kopecek

Dissertations and Theses

The purpose of these studies was to determine if results similar to those of Fleischmann and Pons could be obtained using a titanium cathode instead of palladium in an electrolysis in a heavy water cell. The electrolyte consists of D₂O and H₂SO₄. Two experiments have been performed to examine the features of this electrolysis. As titanium shows the same properties to attract hydrogen, it seemed possible that excess heat could be produced. Radiation was monitored, and the surface of the titanium cathode was examined before and after electrolysis for any changes in the morphology …

Modeling Of Decay Rate For Molecules At An Island Surface, Ting Xiong

Dissertations and Theses

The decay rates for molecules at rough surfaces are studied via an island surface model, with particular emphasis on the effect due to the distribution of surface roughness. Two extreme cases are studied when the surface islands distribute themselves evenly and when they coalesce to form local clusters at the molecule-substrate interface. The optical properties of the interfacial layer in these two cases are described by the Maxwell-Garnett and the fractal-cluster models, respectively. Among other results, it is found that both enhancement and suppression of the surface-induced decay rates are possible due to the presence of roughness, with more dramatic …

Optimal Wavefront Reconstruction For A Coherent Diffracted Field, William W. Arrasmith

Theses and Dissertations

In sheared coherent beam interferometric imaging, an estimate of the average reflectivity profile of the object can be computed from measurements of point to point phase differences in the far field interference pattern and a suitable phase reconstruction technique. The phase difference information is encoded in the irradiance of three identical, shifted and superimposed speckled laser beam patterns. A minimum variance phase reconstruction technique is presented to estimate the phase of the field in the measurement plane from the phase differences and evaluate its performance. Prior knowledge of the phase covariance is used in the minimum variance reconstructor. Analytic calculations …

Bandwidth And Additive Bandwidth Of Graphs, Maria Kujawski

Honors Capstone Projects and Theses

No abstract provided.

An Experimental Apparatus For Studying Differential Scattering Of Multiply-Charged Ions From Neutral Targets Following Capture, John Edward Edens

Masters Theses

An experimental apparatus has been designed, enabling measurement of angular differential cross sections for single-electron capture (SEC). The design consists of a microchannel plate detector with a one-dimensional position sensitive anode. A bow-time shaped aperture was employed to convert a radially scattered distribution into an approximate linear one. An electrostatic retarding grid was used to separate SEC contributions from the reaction products. Measurements were made of the angular differential cross sections for SEC of Ar^q+ (q=4-6,8) ions scattering from He and Ar at impact energies of 600 to 3000 eV and angles between 0 and 23 mrad. The experimental …

Identification And Characterization Of The Iron-Zinc Intermetallics Formed In Galvanneal Steel, Richard Frederick George Grant

Physics Theses & Dissertations

The demand to improve the corrosion resistance of steel sheet, particularly for use within the automotive industry, has led to a dramatic increase in the use of coated steels in place of cold-rolled sheet steel. Galvanneal steel results from the post annealing of the zinc-coated steel sheet, in which iron and zinc are interdiffused to form an iron-zinc alloy coating. Within this alloy coating, four main iron-zinc phases, Zeta, Delta, Gamma-1, and Gamma may be present. Manufacture of the most suitable coating requires identifying which phases form during the galvannealing process, an understanding of the properties of each phase and …

Excited-State Magnesium-Rare Gas Optical Collisions, Rosemary A. Lasell

Physics Theses & Dissertations

Polarization and intensity spectra have been obtained for excited-state magnesium (3s3p ¹P₁) - rare gas optical collisions. The magnesium was excited by a linearly polarized laser tuned to the 3s²1s₀ → 3s3p ¹P₁ atomic transition at 285 nm. A second linearly polarized laser was tuned near the 3s3p ¹P₁ → 3s5s ¹S₀ transition at 571 nm (experiment A) and near the 3s3p ¹P₁ → 3s4d ¹D₂ transition at 553 nm (experiment B). The polarization vector of the second laser was oriented either parallel or …

Measurement Of Hyperfine Coupling Constants Of The 5d²D₃/₂ And 5d²D₅/₂ Levels In Atomic Cesium Using Polarization Quantum Beat Spectroscopy, Wo Yei

Physics Theses & Dissertations

Accurate measurements of hyperfine constants have revealed effects that can not be explained by a simple hydrogenic picture of the alkali atoms such as cesium [1-3]. More precise experimental results and theoretical treatments are in demand for the alkali elements, especially for atomic cesium because of its wide range of applications. Therefore, it is essential to understand its atomic and nuclear structure. Precision measurement of its excited-states properties such as hyperfine structure provides global information on nuclear charge and current distributions and also serves as a check to the theory and a calibration of calculated excited state wave functions. Accurate …

Ultra-Thin Silicon Wafer Bonding, Diyu Yan

Theses

In this thesis the history and recent developments on the silicon direct bonding technique are reviewed. The growing applications of this technique in SOI, SOS and MEMS areas, difficulties and disadvantages of various bonding processes are discussed. A direct bonding procedure for attaching ultra-thin wafers less than 200 μm thick to substrate wafers is developed and described in detail. Difficulties in handling, aligning and annealing ultra-thin wafers are reported. Wafers of different doping concentration, thickness, surface roughness and chemical characteristics are tested for bondability. Methods to minimize voids and other failure mechanisms are proposed. A photodetector is designed based on …

A High Temperature Pressure Sensor Based On Magnetic Coupling And Silicon Wafer Bonding, Deguang Zhu

Theses

In this thesis, the design and fabrication of a bulk micromachined and wafer bonded pressure sensor for high temperature applications is described. The device design is based on the magnetic coupling principle as described by the Biot-Savart law. By combining the mechanical properties of single crystal silicon with magnetic coupling, the designed sensor can be operated up to 600°C. The key components within the sensor are two inductive coils, a silicon diaphragm and a hermetic vacuum cavity.

The modeling based on a nine-turn single level coil device and a 300 μm x 300 diaphragm indicates an output rms voltage range …

Microaccelerometer With Mechanically-Latched Memory, Zhenyu Ma

Theses

A new mechanically-latching micromachined accelerometer is designed in this thesis based on the large deflection of a microcantilever beam. This surface micromachined device moves in the plane of the substrate surface. This device is surface micromachined with no backside etching needed. The interaction of the friction tether and the dimensions of the cantilever beam have been modeled and calculated. The design acceleration sensitivity range is from 100G to 1000G. The photomask set has been designed by using the Mentor Graphics system. The dimension of individual accelerometers ranges from 100 to 1000 micrometers in length to tens of micrometers in width. …

Silicon Optical Fiber Pressure Sensor, Jian Pan

Theses

A novel optical fiber pressure sensor based on a micromachined thin silicon diaphragm is proposed. Detail descriptions of the sensor structure, modulation principle and fabrication process are given.

The device operates on the following principle: Pressure deflects a silicon diaphragm which moves the output end of a light source fiber. The emitted light intensity is picked up and shared by two receiving fibers placed side by side. The variation of the intensity ratio in the receiving fibers caused by the relative motion of the emitting fiber can be easily converted to a linear signal versus the deflection of the silicon …

Beam Dynamics In The Cebaf Superconducting Cavities, Zenghai Li

Dissertations, Theses, and Masters Projects

This work is a study of beam dynamics in the CEBAF superconducting cavities under the influence of the fields generated by externally applied RF and beam particles.;A full 3-D modeling of the CEBAF 5-cell superconducting cavity is carried out. Details of the modeling with MAFIA are discussed. Multipole fields due to the asymmetric couplers are studied by means of 3-D Fourier transforms. The cavity steering and focusing of the multipole fields are studied. Experimental measurements of these effects are performed to validate the modeling. Evaluation of the cavity misalignment is discussed. The emittance degradation effects in the CEBAF superconducting linacs …

Dynamic Phase Steepening In Alfven Waves, Stephen R. Granade

Honors Theses

Our solar system contains more activity and complexity than can be seen through a telescope. One such "invisible" phenomenon is the solar wind, created by a steady stream of particles blasted away from the sun in all directions. The sun's donut-shaped magnetic field lines channel this stream. Particles moving along the field lines perform an intricate helical dance, with ions winding one way and electrons the other.

The solar wind shapes and is shaped by the magnetic fields of the planets and the sun. If left undisturbed by outside influences, the earth's magnetic field, like the sun's, would resemble a …

The Characterization Of The Radiative Energy Transfer Process Among Holmium(3+) Ions In Yttrium(3) Aluminum(5) Oxygen(12), Terri Lynn Lazarus

Dissertations, Theses, and Masters Projects

This research comprises a comprehensive spectroscopic study of the characteristics of the solid state crystal YAG (Yttrium Aluminum Garnet) singly doped with Ho (Holmium) ions. An important area of solid state laser crystal research is the determination and optimization of the processes within these laser crystals which lead to efficient laser action. In most laser crystals, there is a donor ion such as Tm (Thulium) and an acceptor ion such as Ho. The donor ion generally has greater absorption than that of the acceptor at the wavelength of the pump source. The donor ion can transfer this absorbed energy to …

Search For Metastability Of 2s Muonic Neon, Bernard Wilhelm Bach

Dissertations, Theses, and Masters Projects

An experiment was performed at the Paul Scherrer Institut (PSI) to establish the conditions for the metastability of the 2S-state of muonic neon. The muonic atoms were formed by stopping negative muons in the neon-filled target chamber of the PSI cyclotron trap. A pair of intrinsic germanium detectors were used in coincidence to search for the two photon decay of the 2S-state. Both energy and time information from two photon events were written to disk for off-line analysis. Data were accumulated for neon pressures of 40 and 400 Torr. The data were then searched for evidence of two photon transitions …

A Delta-F Monte Carlo Method To Calculate Parameters In Plasmas, Maciek Sasinowski

Dissertations, Theses, and Masters Projects

A Monte Carlo code has been developed which very efficiently calculates plasma parameters, such as currents, potentials and transport coefficients for a fully three dimensional magnetic field configuration. The code computes the deviation, f, of the exact distribution function, f, from the Maxwellian, {dollar}F\sb{lcub}M{rcub},{dollar} with {dollar}\psi{dollar} the toroidal magnetic flux enclosed by a pressure surface and H the Hamiltonian. The particles in the simulation are followed with a traditional Monte Carlo scheme consisting of an orbit step in which new values for the positions and momenta are obtained and a collision step in which a Monte Carlo equivalent of the …

First Principles Linear Response Calculations Of Lattice Dynamics, Cheng-Zhang Wang

Dissertations, Theses, and Masters Projects

First principles calculations, using the density-functional theory and particularly the local density approximation (LDA), have achieved remarkable success in studying the properties of solid state systems. Although the basic results of these calculations are the electronic structures (eigenvalues, eigenfunctions, etc.) and the total energy of ground state, many other related physical properties can be deduced from them by investigating their response under external perturbations. Using the linear response method with linearized-augmented-plane-wave (LAPW) basis, we have calculated lattice dynamical properties of important semiconductors CuCl, SiC and ferroelectric KNbO{dollar}\sb3.{dollar} CuCl is known to exhibit large anharmonic effects and possibly a complicated multi-well …

Applicability Of Bispectral Analysis To Unstable Plasma Waves, Renaud Stauber

Graduate Theses, Dissertations, and Problem Reports

A program to implement a spectral analysis technique called the bispectrum was written and tested with computer generated time series data. The application of the algorithm to the study of nonlinear interactions was demonstrated by a comparison of computed quantities with results from model equations found in the literature. Specifically determined were: the amplitude and phase of coupling coefficients, the power transfer function, the fraction of power associated with nonlinear coupling, and the identification of waves involved in a quadratic coupling interaction. A method of distinguishing the two parent waves from the daughter wave in this three-wave interaction is proposed …

Calculations Of The Interactions Of Energetic Ions With Materials For Protection Of Computer Memory And Biological Systems, Myung-Hee Y. Kim

Dissertations, Theses, and Masters Projects

Theoretical calculations were performed for the propagation and interactions of particles having high atomic numbers and energy through diverse shield materials including polymeric materials and epoxy-bound lunar regolith by using transport codes for laboratory ion beams and the cosmic ray spectrum. Heavy ions fragment and lose energy upon interactions with shielding materials of specified elemental composition, density, and thickness. A fragmenting heavy iron ion produces hundreds of isotopes during nuclear reactions, which are treated in the solution of the transport problem used here. A reduced set of 80 isotopes is sufficient to represent the charge distribution, but a minimum of …

Compensation And Characterization Of Gallium Arsenide, Randy A. Roush

Electrical & Computer Engineering Theses & Dissertations

The properties of transition metals in gallium arsenide have been previously investigated extensively with respect to activation energies, but little effort has been made to correlate processing parameters with electronic characteristics. Diffusion of copper in gallium arsenide is of technological importance due to the development of GaAs:Cu bistable photoconductive devices. Several techniques are demonstrated in this work to develop and characterize compensated gallium arsenide wafers. The material is created by the thermal diffusion of copper into silicon-doped GaAs. Transition metals generally form deep and shallow acceptors in GaAs, and therefore compensation is possible by material processing such that the shallow …

Theoretical Investigation Of Two-Color, Two-Photon, 6s(2)S(1/2) → 5d(2)D(J) → 11p(2)P(3/2) Excitation And Depolarization Spectra In Atomic Cesium, Boris Dobrydnev

Physics Theses & Dissertations

The theoretical investigation of two-photon, two-color intensity and depolarization spectra for the 6s²S_1/2 → 5d²D_j → 11p²P_3/2 transition in atomic caesium is considered. For quadrupole-dipole transitions the dependence of excitation from the ratio of reduced matrix elements is shown. The experimental method of determination of the value and sign of the ratio is proposed. Comparison of results for co- and counterpropagating beams revealed the strong dependence of the transition rate on the relative beam directions. Analysis of the influence of the external electric field on the process of absorption is presented. …

Precision Measurement Of Relative Dipole Matrix Elements In Atomic Sodium, Rodney P. Meyer

Physics Theses & Dissertations

Relative dipole matrix elements are measured by means of a new spectroscopic technique called polarization interference spectroscopy. It is a two-color two-photon nonresonant process that maps the matrix elements into the energy domain by means of quantum mechanical interference. The technique measures the relative magnitude of the reduced matrix elements, particularly those involving excited states, to accuracies that are an order of magnitude better than previously available. Also, for the first time the relative phase of the reduced matrix elements is measured. The ratio of reduced matrix elements for the transitions 3s ²S_1/2 →3P ²P_3/2 →5s …