Index Catalog // ScholarsArchive@OSU

Simultaneous beta/gamma digital spectroscopy

Creator:: Farsoni, Abdollah T.
Abstract:: A state-of-the-art radiation detection system for simultaneous spectroscopy of beta-particles and gamma-rays has been developed. The system utilizes a triplelayer phoswich detector and a customized Digital Pulse Processor (DPP) built in our laboratory. The DPP board was designed to digitally capture the analog signal pulses and, following several digital preprocessing...
Resource Type:: Dissertation

Physical processes that control droplet transport in rock fracture systems

Creator:: Hay, Katrina M.
Abstract:: Aquifer recharge is generally driven by fluids that move from the Earth’s surface to groundwater through the unsaturated zone, also known as the vadose zone. When the vadose zone is fractured, fluids, which may include contaminants, can move through the fracture network as well as the porous matrix. Such a...
Resource Type:: Dissertation

Exchange interaction studies in magnetic semiconductors by neutron scattering

Creator:: Wiren, Zachary Quincy
Abstract:: Theories predict that making a dilute magnetic semiconductor strongly p -type would allow it to remain ferromagnetic at room temperature. This is of intrest as a ferromagnetic semiconductor would allow for a great many applications in the field of spintronics. Neutron scattering experiments were undertaken to better understand the antiferromagnetic...
Resource Type:: Dissertation

Sub-diffraction light propagation and imaging in planar negative refraction waveguides

Creator:: Wangberg, Robyn
Abstract:: In this dissertation we study the electromagnetic properties of planar waveguides with non-magnetic strongly anisotropic dielectric cores. We develop an analytical description of the mode propagation in these systems and show that the index of refraction can be either positive or negative depending on the specific material parameters. Propagating modes...
Resource Type:: Dissertation

A comparison of auditory and visual graphs for use in physics and mathematics

Creator:: Sahyun, Steven Carl
Abstract:: The ability to interpret graphical information is a prime concern in physics as graphs are widely used to give quick summaries of data sets, for pattern recognition, and for analysis of information. While visual graphs have been developed so that their content can be readily and concisely discerned, there is...
Resource Type:: Dissertation

Electromagnetic properties of anisotropic plasmonic metamaterials

Creator:: Elser, Justin Lee
Abstract:: In this dissertation we study the electromagnetic properties of plasmonic metamaterials. We develop an analytical description to solve the fundamental problem of free-space scattering in planar plasmonic systems by utilizing anisotropic metamaterials. We show with exact numerical simulations that these manufactured materials do completely eliminate the scattering, and even in...
Resource Type:: Dissertation

Student views on science and the scientific process : studying changes made in a redesigned non-major introductory science course

Creator:: Price, Matthew F.
Abstract:: The purpose of this study was to understand how instruction in an introductory nonmajor astronomy course at Oregon State University affects how non-science majors view science and the scientific process. The study used research-based methods to design a reform-based lecture/lab course and implement it for students. Two top-level questions were...
Resource Type:: Dissertation

Use of BC-523a liquid scintillator for simultaneous neutron spectroscopy and gamma counting with the implementation of a neutron history reconstruction algorithm

Creator:: Frey, Wesley D.
Abstract:: Real-time, high efficiency neutron spectroscopy has, historically, been a persistent challenge in the field of radiation detection and, for the most part, has gone unsolved. The most promising method to resolve this challenge, is the boron-capture technique using an organic scintillation system (BC-523a). Detectors that utilize this method possess an...
Resource Type:: Dissertation

An extension of the quantum theory of scattering to the non-asymptotic regime using Bohmian trajectories

Creator:: Stenson, Jared R.
Abstract:: Quantum mechanics provides a conventional theory of scattering that is limited in at least two ways: it focuses exclusively on the asymptotic regime and, in a more general sense characteristic of all quantum descriptions, provides no concrete account of individual particle evolution in spacetime. This is particularly true during the...
Resource Type:: Dissertation

A thin codimension-one decomposition of the Hilbert Cube

Creator:: Phon-On, Aniruth
Abstract:: For cell-like upper semicontinuous(usc) decompositions G of finite dimensional manifolds M, the decomposition space M/G turns out to be an ANR provided M/G is finite dimensional ([Dav07], page 129 ). Furthermore, if M/G is finite dimensional and has the Disjoint Disks Property (DDP), then M/G is homeomorphic to M ([Dav07],...
Resource Type:: Dissertation

A study of actinide de-excitation through neutron emission from the deuteron induced fission of ²³⁸U

Creator:: Sprunger, Peter Hayden
Abstract:: The process of de-excitation of the actinides is a very important question in both pure and applied science. In this dissertation the process was studied using the neutrons emitted in coincidence with fission induced by the bombardment of ²³⁸U with 14.85 MeV deuterons. Neutrons can be emitted at multiple stages...
Resource Type:: Dissertation

Computational nanooptics in hyperbolic metamaterials and plasmonic structures

Creator:: Thongrattanasiri, Sukosin
Abstract:: This dissertation concerns several problems in the fields of light interaction with nanostructured media, metamaterials, and plasmonics. We present a technique capable of extending operational bandwidth of hyperbolic metamaterials based on interleaved highly-doped InGaAs and undoped AlInAs multilayer stacks. The experimental results confirm theoretical predictions, exhibiting broadband negative refraction response...
Resource Type:: Dissertation

Submerged jet impingement boiling thermal management

Creator:: Cardenas, Ruander
Abstract:: Technologies such as avionics and power electronics are driving the demand for thermal management schemes towards high heat fluxes and low surface temperatures. Typically, these applications require the dissipation of heat fluxes in the rage of 100-1000 W/cm² while maintaining surface temperatures lower than about 85 °C. Phase-change heat transfer...
Resource Type:: Dissertation

An Ising-like model to predict dielectric properties of the relaxor ferroelectric solid solution BaTiO3 - Bi(Zn1/2Ti1/2)O3, An Ising-like model to predict dielectric properties of the relaxor ferroelectric solid solution BaTiO₃ − Bi(Zn₁/₂Ti₁/₂)O₃

Creator:: Jackson, Dennis L.
Abstract:: We developed a model to investigate the dielectric properties of the BaTiO₃ − Bi(Zn₁/₂Ti₁/₂)O₃ (BT-BZT) solid solution, which is a relaxor ferroelectric and exhibits long range disorder. The model uses ab initio methods to determine all polarization states for every atomic configuration of 2 x 2 x 2 supercells of...
Resource Type:: Dissertation

Model of student understanding of probability in modern physics

Creator:: Wattanakasiwich, Pornrat
Abstract:: This study aimed to investigate students' models of probability in a modern physics context. The study was divided into three phases. The first phase explored student pre-knowledge about probability before modem physics instruction. The second phase investigated student understanding of concepts related to probability such as wave-particle behavior, the uncertainty...
Resource Type:: Dissertation

Level structure of ¹⁵²Gd populated in ¹⁵²Tb β decay

Creator:: Stapels, Christopher John
Abstract:: As part of a research program to study the transitional region of N=88 isotones, ¹⁵²Tb was produced by the reaction ¹⁵¹Eu(α,3n)¹⁵²Tb in the 88" cyclotron located at LBNL. Gamma-ray spectroscopy of the radiation emitted from excited ¹⁵²Gd following the β⁺ decay of ¹⁵²Tb has been performed using an array of...
Resource Type:: Dissertation

Discrete-time quantum walks via interchange framework and memory in quantum evolution

Creator:: Dimcovic, Zlatko
Abstract:: One of the newer and rapidly developing approaches in quantum computing is based on "quantum walks," which are quantum processes on discrete space that evolve in either discrete or continuous time and are characterized by mixing of components at each step. The idea emerged in analogy with the classical random...
Resource Type:: Dissertation

Monte Carlo simulations of magnetic semiconducting Superlattices

Creator:: Scott, Silas Menlo
Abstract:: Computer simulations invoking the Metropolis Algorithm and Monte Carlo techniques were constructed to model the behavior ofvarious systems of magnetic semiconductors. Among the systems modeled were bulk type II FCC antiferromagnets and simple cubic thin films and superlattices. Studies of bulk antiferromagnets revealed dependence of Neel Temperature on nearest neighbor...
Resource Type:: Dissertation

A theoretical description of anisotropic chemical association and its application to hydrogen-bonded fluids

Creator:: Peery, Travis B.
Abstract:: The thermodynamic and structural effects of highly anisotropic, short-ranged attraction are investigated for single- and four-site interaction models using Wertheim's multi-density graph theory of chemical association. Both models consist of associating hard spheres, where the saturable attraction sites are described by conical wells centered in the hard core and evaluated...
Resource Type:: Dissertation

Design, construction, and characterization of a neutron depth profiling facility at the Oregon State University TRIGA® reactor with an advanced digital spectroscopy system

Creator:: Robinson, Joshua A.
Abstract:: In this work, Neutron Depth Profiling (NDP) analysis capability has been added to the Oregon State University TRIGA® Reactor Prompt Gamma Neutron Activation Analysis Facility (PGNAA). This system has been implemented with an advanced digital spectroscopy system and is capable of rise time pulse shape analysis as well as coincidence...
Resource Type:: Dissertation

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