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...
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...
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...
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...
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...
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...
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...
The purpose of this study is to measure and compare radiation emissions from flames burning large hydrocarbon fuels to assist in understanding how the molecular composition changes radiation emissions. Radiative heat transfer is significant because it is a primary mode of heat transfer for many combustion devices. This study also...
The aviation industry is pushing for better fuels and gas turbine engines for several reasons: cost, emissions, and to a lesser extent high-altitude relights. One aspect that research has been focused on to help reduce costs, emissions and better understand high-altitude relights is studying the combustion behavior of the fuel...
Hydropower is the one of the oldest renewable energy technologies and is wrongly thought of today as having little room to grow. The opportunity for new hydropower capacity is immense through both technology advancement and run-of-river new stream reach projects. Despite the age of hydropower, a divide in opinion is...
AMD SEV allows for the creation of fully encrypted virtual machines. This allows cloud computing tenants’ data to be secret to the cloud computing provider. However, it has been shown that the encryption scheme used by AMD can easily be broken. The attacker can create a copy of the virtual...
Large-hydrocarbon fuels are used for ground and air transportation because of their high energy-density and will be for the foreseeable future. However, combustion of large-hydrocarbon fuels in a turbulent environment is poorly understood and difficult to predict. The turbulent flame speed, which is the velocity at which a flame front...
The objectives of this study are to use SAP2000 to investigate lateral load paths and system behavior in a modular, light-frame wood structure by investigating different foundation configurations and to further develop and validate existing modeling techniques of shear wall elements based on the Perforated Shear Wall Method. The modeling...
The Moderate or Intense Low-oxygen Dilution (MILD) combustion regime has received interest from the industrial furnace and gas turbine engine industries due to attractive properties of reduced NO[subscript x] emissions and high thermal efficiency. MILD combustion is characterized by low oxygen concentrations (i.e. 3%-9% by volume) and high reactant temperatures....
Many applications require not only representing variability in software and data, butalso computing with it. To do so efficiently requires variational data structures thatmake variability explicit in the underlying data and the operations used to manipulate it.Variational data structures have been developed ad hoc for many applications, but thereis little...
This thesis proposes a novel technique that exploits spectrum occupancy behaviors inherent to wideband spectrum access to enable efficient cooperative spectrum sensing. The proposed technique reduces the number of required sensing measurements while accurately recovering spectrum occupancy information. It does so by leveraging compressive sampling theory to exploit the block-like...
Spot fires caused by lofted embers (i.e., firebrands) can be a significant factor in the spread of wildland fires. Embers can be especially dangerous near the wildland-urban interface (WUI) because of the potential for the fire to be spread near or on structures. Many studies have investigated the transport of...
Modeling tire-snow interaction is important in designing effective snow tires, which directly affects road safety during wintry weather. Unfortunately, tires have complex tread designs and the physical properties of snow have not been characterized. We employ the Material Point Method (MPM) for simulating a material that mimics the fracturing and...
Large databases and data warehouses are becoming prevalent for the storage and management of energy data. Accelerating the rates at which data can be retrieved is beneficial not only to allow for more efficient search of the data, but also to be integrated with other energy system tools. In this...
Large amounts of energy are wasted when conditioned air in buildings is exhausted to meet ventilation requirements. There are several technologies to recover some of this energy, including the recent development of membrane based energy recovery ventilators (ERVs). ERVs exchange sensible heat and moisture between incoming fresh and outgoing exhaust...
Numerous physical and chemical processes are required for successful ignition of a flammable mixture, many of which have been well characterized. However, one aspect of the ignition process that has received limited consideration is understanding the temperature of the spark kernel. A spark kernel is the volume of heated gas...
Geographical datasets are large, complex, and can be difficult for users to navigate and derive meaning from. These datasets, as well as the unique insights derived from them, provide tremendous opportunity for social change -- many of the global challenges humankind is currently facing can benefit from analytics or visualization...
A 1 kW series hybrid powertrain was developed at Oregon State University for use in unmanned aerial vehicles (UAVs). This powertrain was designed to give mission flexibility and increased flight time to fixed-wing vertical takeoff and landing UAVs and multirotor UAVs. The powertrain components, an internal combustion engine and a...
Oscillating foil energy harvesters are analyzed at optimal reduced frequencies (𝑘=𝑓𝑐/𝑈) to determine how the leading edge radius of curvature affects leading edge separation. The understanding of leading edge separation and its behaviors is critical to predicting the transient lift profile of an airfoil. The separation is therefore also critical...
Smoldering can play a dangerous role in the ignition and spread of wildfires. Naturally occurring fuels consist of multiple layers of organic materials with varying particle sizes due to differences in decomposition stages with fuel depth, yet the influence of particle size on burning behavior is poorly understood. Previous research...
In the current education environment, many instructors make use of some type of software, such as Visual Studio or a software library like OpenGL, in the classroom. Incorrect setup and configuration on an individual’s own system is a common problem when using these software tools. This thesis explores the difficulty...
Connections in mass timber structural systems dissipate energy and transfer lateral forces from mass timber elements such as shear walls and diaphragms, providing critical load paths. Cross-laminated timber (CLT) is a prominent mass timber material used to manufacture wall and floor assemblies. Fire performance research of CLT walls and floors...
The purpose of this research was to determine the effectiveness
of a personal finance workshop as measured by a multiple choice
competency test. More specifically the objectives of the study
were: 1) to develop a valid instrument for measuring the participants'
learning as a result of a two and half...
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...
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...