Vacuum arc remelting (VAR) is a secondary melting process for exotic alloys. The main purpose of this process is to increase the input ingot’s physical and chemical homogeneity. This is accomplished through the application of a high current that melts the material through the emergence of electrical arcs that induce...
Modern scientific and engineering problems often require simulations with a level of resolution difficult to achieve in reasonable amounts of time—even in effectively parallelized programs. Therefore, applications that exploit high performance computing (HPC) systems have become invaluable in academia and industry over the past two decades. Addressing the questions that...
Simulations of combustion and reacting flows often encounter stiffness in the equations governing chemical kinetics. Explicit solvers for these ordinary differential equations offer low computational expense, but typically cannot efficiently handle stiff systems. In contrast, implicit methods demand greater expense but offer unconditional stability—as a result, most reactive-flow solvers rely...
Engineering applications often require fast, accurate solutions of fluid flow around freely moving bodies. The massive parallelism enabled by graphics processing unit (GPU) architecture enables high performance, offering a promising alternative to traditional solver acceleration via multicore central processing units (CPU). However, fully harnessing GPU parallelism requires specialized algorithms and...
Modeling elementary chemical reactions in ocean fluid dynamics simulations requires significant computing resources, which can be diminished with model reduction techniques. Submesoscale ocean turbulence and biogeochemical reactions in the ocean occur on approximately the same time scale, 105 seconds. This similarity in time scales indicates a strong coupling between these...
The control of feral goats (Capra hircus) and relevant aspects of their biology were studied on Aldabra Atoll, Republic of Seychelles, from October 1993 - May 1994 and November 1994 - May 1995. A total of 832 goats were killed on Aldabra using both the Judas goat technique and traditional...
A population of Spermophilus beecheyi was studied to determine
patterns of individual spacing, behavioral interactions among different
sex and age classes, and the relationship between aspects of S. beecheyi
social structure and sociality to those of other sciurids. Research was
conducted on a population of squirrels living in an abandoned...
Feral goat (Capra hircus) populations adversely impact native insular biota and physical habitats worldwide. The effectiveness of the Judas goat technique for eradicating remnant feral goats was studied on San Clemente Island (SCI), California from June 1989 through April 1991. By April 1991, 263 feral goats were killed on SCI;...
Deforestation and forest fragmentation are the primary threats to the habitat
of endangered lion-tailed macaques, Macaca silenus, in Karnataka, India. Landsat
satellite images of northwest Karnataka, India, from 1977 and 1990 were analyzed.
Two study sites, measuring 16.35 x 19.14 km (31,213 ha) and 14.34 x 21.44 km (30,561
ha),...
A cow-calf herd of Roosevelt elk (Cervus elaphus roosevelti)
resident to Indian Creek Research Center (ICRC), Oregon was observed
June-August, 1985 and March-August, 1986. Cows at ICRC reproduced in
alternate years; cows with calves led the herd a significantly
greater number of times than cows without calves (1985, P <...
The potential for Rocky Mountain mule deer (Odocoileus hemionus hemionus)
to host exotic chewing lice (Damalinia (Cervicola) sp.) believed to cause deer hair
loss syndrome in Columbian black-tailed deer (Odocoileus hemionus columbianus),
was investigated in captive deer held in pens at E.E. Wilson Wildlife Area, Corvallis,
Oregon from March 2004...
:
_____________________________________________________________________
Bruce E. Coblentz
The potential for Rocky Mountain mule deer (Odocoileus hemionus
Characteristics of minke whale (Balaenoptera acutorostrata) habitat at the head of the Laurentian Channel in the St. Lawrence Estuary, Canada were identified by quantifying environmental and temporal habitat variables and comparing them to the presence or absence of minke whales during the summer of 1996. Identification photographs of minke whales...
Forage availability, diets, distribution, and productivity were
compared for Roosevelt elk, Cervus elaphus roosevelti, using improved
(i.e. seeded, fertilized, and grazed) and untreated areas of the Oregon
Coast Range. Seasonal forage availability was substantially different
on 1-year-old improved and untreated clearcuts, but the differences
diminished by clearcut age 4 and...
The garibaldi, Hypsypops rubicundus, is a sexually monochromatic pomacentrid found in rocky subtidal areas of Southern and Baja California. During the spawning season, males attempt to attract females to a nest of red algae located within individually defended territories. Females were observed to enter the nests of several males before...
I investigated the population attributes and habitat
selection of mountain beaver (Aplodontia rufa) recolonizing
clearcuts in the Coast Range mountains of Polk and Lincoln
counties, Oregon between June 1989 and August 1990. The
population characteristics of colonizing mountain beaver
were evaluated in 12 stands of 3 types: 1-year-old
clearcuts assumed...
California bighorn sheep (Ovis canadensis californiana) were studied on Hart Mountain, Oregon, during the summer and fall of 1976, and the spring of 1977. The population consisted of a minimum of 196 sheep in June, 1977. The high number of lambs observed and high lamb:ewe ratios throughout both years of...
A herd of California bighorn sheep (Ovis canadensis californiana),
re-introduced to the area of Hell Creek on the Sheldon National
Wildlife Refuge in northwestern Nevada, was studied from 15 June 1978
to 20 August 1980.
Major vegetation and physiographic types were delineated and
described. Habitat preferences were determined from field...
Recently the National Park Service has proposed raising fence heights to exclude mouflon sheep (Ovis musimon) from conservation areas at Hawai'i Volcanoes National Park. Concern over previous mortality of Hawaiian Petrels (Pterodronia sandwichensis) due to collision with fences prompted this study to quantify the potential effects of raising fence heights...
Aspects of bison ecology and behavior were studied in the Henry
Mountains, Utah during summer 1977 and summer 1978. Foraging
distributions of bison and of cattle were compared to elevation, slope,
horizontal distance from water, vertical distance from water, aspect,
and availability of preferred forage. The effect of bison-cattle
interactions...
The movements, habitat use, and activity patterns of black-tailed deer in western Oregon, and the influence of suburban housing developments on the behavior of deer in the area, were studied and described. Radio telemetry, spotlight censusing, and a resident questionnaire were used to document the behavior of deer. Radio telemetry...
Due to global warming wildland fires are increasing in frequency and severity. In the case of wildland fires, the major modes of combustion occur include smoldering combustion and flaming combustion. Smoldering combustion occurs most commonly in porous fuels like peat, forest duff, and woody fuels, which are available in abundance...
For this project, we designed a soot modeling software to produce a full particle density function. This model uses the Direct Simulation Monte Carlo with a full conditioning particle selection method to capture soot nucleation and coagulation in a diffusion flame. We investigate the use of graphic processing units as...
As carbon emissions are negatively impacting ecosystems across the globe, researchers are in a race against time to provide cleaner and more eÿcient power. Detonation engines can help meet the increasing demands for cleaner and more eÿcient power generation by providing an alternative means to use oxy-fuel combustion for carbon...
Small hydrocarbon particles such as soot and soot precursors pose a serious threat to human health and Earth's climate. Understanding the mechanisms by which soot particles form and grow is the first step to reducing the prevalence of these particles. Computational simulations are used to investigate combusting systems which are...
High-potential molecules derived from biomass sources may suitably replace or supplement traditional nonrenewable hydrocarbon fuels to reduce pollution and fuel processing costs. Due to expensive and time-consuming property testing, models that predict key properties from optical data would initially vet potential additives before investment and bench-scale testing. Attenuated Total Reflection...
In this work, I developed a six degree of freedom flight simulator specific to liquid engine launch vehicles. This flight simulator improves upon available software by accounting for liquid engine specific phenomena such as tank pressurization, liquid engine performance, and center of gravity modeling. Additionally, I implemented methods for optimization...
In this paper, I present the design of Mira 2, a small-scale, liquid bipropellant rocket engine, with a specific focus on its oxidizer-centered pintle injector. Building upon the valuable lessons and insights gained from the empirical testing of its predecessor, Mira 1, the Mira 2 engine incorporates several improvements and...
The purpose of the study was to analyze the possible combination of cooling systems, which are film cooling and regenerative cooling, and obtain the initial estimates of possible temperature reduction. The analysis was conducted in Ansys Fluent. The methodology includes four main steps that are the following: flow simulation, combustion...
Carbon tetrachloride (CT) and chloroform (CF) were transformed in batch reactor experiments conducted with anaerobic dechlorinating cultures and supernatant (ADC+S) harvested from continuous flow reactors. The Evanite (EV-5L) and Victoria/Stanford (VS-5L) cultures capable of respiring trichloroethene (TCE), 1,2-cis-dichloroethene (cDCE), and vinyl chloride (VC) to ethene (ETH) were grown in continuous...
High Temperature Gas Reactors (HTGR) are a type of power plants that can provide industrial process heat and high efficiency, carbon-free electricity. The High Temperature Test Facility (HTTF) has been designed to provide data that can be used for the validation of system codes and verification of passive safety features...
Both conflicts and new identities result when indigenous' traditional values of landscape and resource management are superimposed with federal governments' management of archaeological and forest resources in federally designated protected areas. This thesis examines the relationship and discourse between two Cuicatec towns in Oaxaca, Mexico and three Mexican government agencies...
Marine debris is a chronic and increasingly pervasive problem for coastal regions around the world. Debris poses environmental risks, threats to wildlife, and degradation of the natural environment. Recent research has shown the advantages of uncrewed aircraft systems (UAS) for detection and recognition of marine debris, including the ability to...
This study explored the relationship among marital role expectations,
religiosity, and other variables including age, dating status of
subjects, living arrangement, marriage plans and parents' marriage.
Data were obtained from a sample of 460 Oregon State University
students in April, 1976. They were primarily young students, 18 - 19
years...
Bullfrogs were introduced into Oregon in the early 1900s and have become widespread members of many wetland communities. Little is known of their ecology outside their native range, although they may play a role in the current declines observed in native herpetofauna. I analyzed the diets of 401 bullfrogs from...
Gasoline direct injection engines, with downsized boosted technology, present a promising option for enhancing power density and reducing fuel consumption for next-generation engine designs to meet stringent fuel economy and emission standards. However, these developments in the low-speed and high-load operating regime are challenged by the occurrence of a new...
Low temperature combustion (LTC) engines offer improved efficiency and reduced emissions over traditional gasoline spark-ignited and diesel compression-ignition engines. The ability to produce fuels optimized for LTC engines could help increase efficiency and therefore improve fuel economy, insomuch that Federal fuel economy standards could be met. Currently, a fuel performance...
In the United States, the oil and gas extraction industry produces large amounts of highly contaminated wastewater that is seldom treated for reuse in other applications. Current wastewater storage and disposal strategies lead to contamination of valuable freshwater resources that can have negative effects on both human communities and the...
Earthquake engineering analyses are often performed using shallow, crustal earthquake motions (e.g., 1940 El Centro). However, large areas of the world are subject to subduction zone earthquake motions (e.g., the Pacific Northwest). A subduction zone earthquake motion is characterized by its long duration (e.g., strong shaking lasts for more than...
Understanding the causal links between riparian forests, streams, and salmonids is important to help understand the likely effects of forest management practices. Previous studies have identified three major causal pathways (Instream Cover, Light, and Hydrology) through which riparian forests influence streams, and ultimately stream fishes. To evaluate the potential importance...
Sphaerulina musiva is a fungal pathogen that causes Septoria leaf spot and stem canker on susceptible Populus species and hybrids. In this thesis, host and pathogen contributions to Septoria stem canker disease were explored through: 1) a greenhouse study associating Septoria stem canker phenotypes with molecular markers from a genetic...
Oil drilling requires that miles of steel drill pipe, called the drill string, be exposed to fatigue loading and corrosive environments. Furthermore, it has been reported that pitting corrosion is responsible for initiating catastrophic drillstring failure. Pitting corrosion is responsible for initiating fatigue cracks, with pits acting as local stress...
Small broomrape, a holoparasitic weed, is a relatively new weed introduction in the Pacific Northwest that has contaminated a limited number of red clover fields in Oregon. Greenhouse and field studies were conducted to evaluate small broomrape response to common crop and weed species in the Pacific Northwest. Host species...
Flow rate sensors for in situ gas or liquid monitoring typically comprise multiple transducer elements, including a heater and one or more temperature sensors to measure the rate of heat energy removal by the flowing fluid. The need for multiple transducer elements limits feasibility of shrinking these sensors to microfluidic...
Recent experiments have advanced the current understanding of multi-nucleon transfer(MNT) reactions. Within nuclear science, most nuclear reaction experiments consist of a stationary target material, that is then bombarded by a moving projectile. Overall nuclear reactions can be used to produce a desired isotope. In the case of this particular study...
The ability to accurately locate people and objects indoors will enable opportunities for control and automation of indoor environments. Current indoor localization solutions require dedicated hardware which must be custom tailored to each application. There are large technological, societal, and economic benefits in developing a more general purpose system that...
Recent changes in legislation restricting lead content in waste streams produced during electronics manufacturing have inspired a strong push to develop alternative lead-free materials systems for piezoelectric applications. One lead-free piezoelectric material system, (100-X)Bi₀.₅Na₀.₅TiO₃-XBi₀.₅K₀.₅TiO₃ (BNKT), has shown promising properties in bulk research, however, difficulties have arisen in the development of...
The goal of this project is to contribute to the development of design values for cross-laminated timber (CLT) diaphragms in the seismic load-resisting system for buildings. Monotonic and cyclic tests to determine strength and stiffness characteristics of 2.44 m (8 ft) long shear connections with common self-tapping screws were performed....