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...
This thesis deals with applications of uniaxial anisotropic crystals for microcavity resonators with partially chaotic underlying ray dynamics. We develop an implementation of the scattering matrix formalism, and relate the eigenvalues and eigenvectors of the scattering matrix to the field distribution of inside the system. Using the developed technique, we...
Reflux condensation tests examining steam condensation in a PWR steam generator (SG) were conducted at the Oregon State University (OSU) Advanced Plant Experiment (APEX) Test Facility from 2005 through 2007. The experimental data collected will provide a basis to assess TRACE steam generator modeling techniques and assist in development of...
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...
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...
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...
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...
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...
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...
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...
Modern wind energy is the technology of choice with a short payback period for increasing renewable energy portfolios. Bonneville Power Administration (BPA), a United States power authority in the Pacific Northwest expects to increase their wind energy capacity from 2,000 megawatts to 6,000 megawatts within the next five years. Currently...
The main objective of the research is to develop a prototype device that can determine the condition of the thermally sprayed zinc anode in cathodic protection systems. The device needs to meet the following requirements: applicability in the field, non-destructiveness or minimal destructiveness of the zinc anode, ease of use...
Quadrotors are unique among Micro Aerial Vehicles in providing excellent maneuverability (as opposed to winged flight),while maintaing a simple mechanical construction (as opposed to helicopters). This mechanical simplicity comes at a cost of increased controller complexity. Quadrotors are inherently unstable, in the sense that they are essentially unflyable by a...
Computing agents require state information to make coherent and useful decisions. A state representation is a numerical translation of the environment and conditions that are pertinent factors in an agent's decision making. Although many representations, when paired with clever learning algorithms, are able to coordinate and capture prey in specific...
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...
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],...
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...
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...
A hybrid Quasi-diffusion/Monte Carlo Method for solving multigroup criticality problems in slab geometry was investigated. Analog Monte Carlo was used to calculate functionals (Eddington Factors) that were then used in solution of the quasi-diffusion equations. The hybrid method was shown to accurately and precisely predict the k-eigenvalue and fission source...
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...