Life cycle exposures to hazards from existing and newly developed products and production processes, demands from external stakeholders for compliance with regulations, requirements from internal stakeholders for connecting management systems to lean company initiatives and market pressures have motivated U.S. based semiconductor companies to adopt an integrated-lean approach to environment,...
Additive manufacturing and 3D printing have become household names as both hobbyistsand industrial manufacturers utilize fast, inexpensive prototyping and production of functionalparts. Additive manufacturing is being revolutionized with 3D printers such as theMulti Jet Fusion 3D from HP, Inc., where each volume pixel, or voxel, can be independentlyfunctionalized. Voxel-by-voxel printing...
Additive manufacturing and 3D printing have become household names as both hobbyistsand industrial manufacturers utilize fast, inexpensive prototyping and production of functionalparts. Additive manufacturing is being revolutionized with 3D printers such as theMulti Jet Fusion 3D from HP, Inc., where each volume pixel, or voxel, can be independentlyfunctionalized. Voxel-by-voxel printing...
The addition of macromolecules to solvent, even in dilute quantities, can significantly alter a fluid's response in an extensional, or stretching, flow. When high-molecular-weight polymers are extended in solution, extensional thickening can result, yielding viscosities that are orders of magnitude larger than values found in shear. Examples of applications where...
Polyethylene terephthalate (PET) polymer has been the material of choice for packaging industry as a result of its excellent mechanical and physical properties. These properties are highly dependent on the microstructure, chemistry, and processing conditions of this material. PET is often oriented in the machine direction (MD), the transverse direction...
The objectives of this study were to (1) describe
physical environmental conditions and species composition
at several sites along an Upstream/downstream gradient in a
number of tributaries of the Willamette River in western
Oregon; and (2) identify possible relationships between
species distributional patterns and physical habitat
parameters using detrended correspondence...
A central theme of ecology is determining factors that influence species distributions. Within aquatic ecology, species present in flowing waters are primarily influenced by the natural flow patterns of the stream (natural flow regime paradigm) while explanations of species present in standing waters are further divided by habitat type. To...
Xanthan gum, a naturally produced polysaccharide, is biocompatible, and it is commonly used as a food additive. When combined with trivalent ions, such as chromium (III), a gel can form. Various concentrations of xanthan gum and chromium (III) nitrate were combined to evaluate the sol-gel transition of this system. Samples...
This project discuses the design of a novel apparatus for measuring the interfacial rheological properties of a complex interface while measuring the concentration of redox species within the sub-phase. Preliminary measurements made using the apparatus are also presented. The objective of the preliminary experimentation was to simultaneously measure the interfacial...
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Travis W. Walker
This project discuses the design of a novel apparatus for measuring the
The Brownian motion of micron-scale particles reflects the viscoelastic response of the local environment of the medium. Tracking the thermal fluctuations of these particles is a measure of the rheology of the material at the microscopic scale. This technique is called passive microrheology. Microrheology has been developed to assess the...
Suspensions of particles in fluids are everywhere in our life, such as paints, pharmacies, food, etc. Suspensions can exhibit properties that common fluids do not possess. For example, the paint needs to flow well when brushing so that it can be smeared on the wall, which is aided by the...
Extending rheological characterization methods to very small length scales is of interest. AC susceptometry using magnetic nanoparticle probes has been proposed for measurement of frequency-dependent rheological properties at the nanoscale. As this technique has been primarily used for ideally Newtonian fluids, this research aimed to extend this technique to viscoelastic...
Insoluble surfactants are unique molecules that have the ability to manipulate interfacial properties, becoming useful in numerous applications such as detergents, wetting agents, emulsifiers, foaming agents, dispersants, and more. Interfacial rheology is a field that attempts to characterize the flow properties of insoluble surfactants by exerting a stress on the...
Highly elastic solutions have been shown to increase contaminant removal from silicon wafers, indicating the possibility for reduced reliance upon hazardous chemicals and expensive technologies during the fabrication of semiconductor devices. The onset of this enhanced removal is explored using rinsing and siphoning experimentswith polymer fluids of high molecular weights...
Intersections pose unique transportation challenges regarding safety and operational efficiency. When pedestrians currently want to cross at intersection, they need to use a push button to issue a call for service. The call is static and cannot be altered or changed. But by implementing dynamic passive pedestrian detection sensors, intersections...
Rising global temperatures are having lasting effects on mountain snow environments in the form of diminishing snowpacks, shorter accumulation seasons, and shifts in meltwater timing. Seasonal snowpack is a vital source of water for natural and human systems. In the forested mountain landscapes of the Pacific Northwest seasonal snowmelt feeds...
Headwater streams are an integral part of the ecological health of the greater stream network as they provide valuable biological habitat, provide upwards to 95% of total in channel flow, while providing downstream reaches with important constituents such as sediment and woody debris. Small headwater streams are particularly susceptible to...
The measurement of extensional viscosity is important in many chemical, biomedical, agricultural, and engineering applications. The determination of extensional viscosity is generally difficult, expensive, and inaccessible outside of research labs. The development of a smartphone application (app) that could use a phone’s high-speed camera to measure this parameter could open...
In the Northwest Great Basin, aspen (Populus tremuloides) communities uniquely contribute to the biodiversity of a semi-arid, sagebrush-dominated landscape. In this same region, western juniper (Juniperus occidentalis) is encroaching into aspen stands. This study determined the timing, extent, and some of the effects of this expansion. Aspen stands below 2,133...
Global Positioning Systems have allowed for precise timing of power system measurements over wide areas. This newly found capability has the potential to provide much greater insight into the operation of the power system and its response to contingencies, but few analytical techniques currently exist that provide enough robustness and...
Microtechnology was used to study the chemical reduction of dissolved carbon dioxide into useful products. A novel TiO₂ photocatalyst was used to activate the reaction under ultraviolet irradiation. CO₂ was dissolved in aqueous and 50% BMIM-BF₄ (ionic liquid) solutions. The introduction of an ionic liquid increased the solubility of CO₂...
Many large-scale data analysis applications involve data that can vary over both time and space. Often the primary goal of analyzing spatiotemporal data is identifying trends, movements, and sudden changes with respect to time, location, or both. This can include a variety of applications in economics (housing prices, unemployment, job...
Green technology in the United States has been on the rise over the past few decades in the United States. However, certain green technologies have been developed in the absence of design standards. Ecoroofs, which are vegetated soil masses placed on the top of a building’s roof structure, present several...
Hatchability of broiler eggs has not increased over the last twenty years. Increasing hatchability with in ovo technology may be possible through feeding metabolic modulators to the developing embryo. Exogenous fatty acids and antioxidants provided during incubation may enhance polyunsaturated fatty acid, lipid, and antioxidant status of the chicken embryo....
Streptococcus gordonii is a bacterial species that naturally colonizes the oral cavity of most healthy humans. It resides in the mouth as an adherent to dental surfaces and, with few exceptions, does not cause disease in individuals it inhabits. It possesses qualities that encourage its use as a vector to...
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...
Seed shattering is a constraint to improvement of seed yield in Lolium perenne L. and as a result, seed retention is an essential trait for this valuable crop. Field studies were conducted near Corvallis, OR in two years (2017-2018 and 2018-2019) to identify genetic variation for seed retention and to...
Quantifying and modeling processes involved in the global carbon cycle is important to evaluate the temporal and spatial variability of these processes and understand the effect of this variability on future response to changing climate and land use patterns. Biomass accumulation and Net Primary Productivity (NPP) are large components of...
The epistemic practices that make up engineering are poorly understood and there is a lack of empirical research on this topic. Characterizing the epistemic practices of engineering students, faculty, and professionals is critical to creating effective curriculum that aids in developing student’s epistemic practices. Doing so allows us to better...
Traditional public health bacterial indicators of water quality and the Biolog® system were evaluated to compare their response to other indicators of stream condition with the state of Oregon and between ecoregions (Coast Range, Willamette Valley, Cascades, and Eastern Oregon). Forty-three randomly selected Oregon rivers were sampled during the summer...
Denitrifying bioreactors are an edge-of-field treatment technology particularly well suited for nitrate removal from subsurface (tile) drainage effluent of agricultural lands. The effectiveness of a proposed denitrifying bioreactor is site-specific and depends upon the complicated interplay of field and environmental parameters controlling discharge events, nitrate concentrations, subsurface temperatures, dissolved oxygen...
Image classification is a difficult problem, often requiring large training sets to get satisfactory results. However this is a task that humans perform very well, and incorporating user feedback into these learning algorithms could help reduce the dependency on large amounts of labeled training data. This process has already been...
Main Street USA in Southern California’s Disneyland theme park is often described as nostalgic. However, previous research on this subject has failed to identify what elements actually make Main Street USA nostalgic as well as determine why Disney uses this nostalgia to influence park guests. In order to respond to...
This study, conducted with the cooperation of the Oregon Comprehensive
Health Planning Agency, Salem, had a threefold purpose:
(1) to identify the role of the physician's assistant (PA) in Oregon,
(2) to provide substantive data for recommendations regarding changes
in PA licensure, and (3) to provide information which may be...
Architects and engineers are two key types of design professionals who influence the use of wood products in construction. Eighty to ninety percent by volume of all residential structures in the U.S. are wood (Gupta, 2005). In 2010, the non-residential market was made up by 10% wood, 60% steel and...
Anne Frances Wysocki, a scholar in the field of new media and composition studies, has published many articles, book chapters, a textbook, and is a major contributor to a multi-authored collection titled Writing New Media: Theory and Applications for Expanding the Teaching of Composition. This thesis considers the five openings...
Forest disturbances, such as wildfires, pine beetle outbreaks, and floods are important features of many landscapes and ecosystems. Many disturbances are increasing in size, frequency, and intensity due to changing climates and land management decisions. The changing ecological and aesthetic conditions following a disturbance can lead to negative short- and...
Heparin was modified and immobilized to surface-activated silica surfaces using two different reaction schemes. End-aminated heparin was reacted with 2-iminothiolane to produce free thiol groups at the terminal ends of the heparin chains. The end-thiolated heparin was immobilized by reaction with a pyridyl disulfide activated poly[ethylene oxide]-poly[propylene oxide]-poly[ethylene oxide] triblock...
In this work, an alternating current (ac) magnetic susceptometer is designed and implemented to track the Brownian relaxation time of magnetic nanoparticles that are suspended in a liquid medium. The detection technique based on the Brownian relaxation time of magnetic nanoparticles has found its way in a variety of biosensing...
Bathymetry and gravity data collected during Legs 5, 6, and 7 of the 1993 GLORIA Expedition and the recently released 2-min altimetry-derived global gravity grid are used to determine the effective elastic thickness of the lithosphere along the Easter Seamount Chain (ESC). Forward modeling, admittance, and coherence methods yield consistent...
Invasive species in riparian forests are unique as their effects can transcend ecosystem boundaries via stream-riparian linkages. The green alder sawfly (Monsoma pulveratum) is an invasive wasp whose larvae are defoliating riparian thin-leaf alder (Alnus tenuifolia) stands across southcentral Alaska. To test the hypothesis that riparian defoliation by this invasive...
Inkjet printing offers a cost effective, highly customizable method for rapid manufacturing of functional devices with minimal material waste. Although this method has been used for a variety of composites, little work has been done in the area of 3D printing magnetic composites. Presented here is a process for inkjet...
Geologic CO₂ sequestration is a climate change mitigation strategy that prevents CO₂ emissions to the atmosphere by capturing CO₂ gasses from large point source emissions streams and then pressurizing and pumping the supercritical-state CO₂ into underground geologic storage reservoirs. Once underground, CO₂ is prevented from buoyant migration to the surface...
Soft magnetic composites, consisting of fine metallic particles in a non-magnetic, insulating matrix, have great potential for integrated inductor and antenna applications. The dielectric and magnetic properties of soft magnetic composites can be tailored by the choice of matrix as well as particle composition, size, and concentration for reduction in...
Lodgepole pine (Pinus contorta) forests are widely distributed throughout western North America. However, the lodgepole pine forests of central Oregon are ecologically unique to the region, with a mixed severity fire regime, low cone serotiny, and their occasional presence as a climax species. Most of the research conducted regarding the...
Silicon wafer cleaning is a ubiquitous unit operation in the semiconductor industry to remove excess material or nanoparticle impurities to obtain perfectly smooth and clean wafer surfaces. Extensive research has already been completed to understand the physics behind hydraulic jumps observed due to balance of forces when a coherent Newtonian...
The Forest Elevation Snow Transect (ForEST) project is a paired site elevational snow study. It is designed to measure how snow accumulates and ablates under different forest structures across an elevation range. The ForEST project has been ongoing since the winter of 2011-2012 within the McKenzie River Basin of the...
The Forest Elevation Snow Transect (ForEST) project is a paired site elevational snow study. It is designed to measure how snow accumulates and ablates under different forest structures across an elevation range. The ForEST project has been ongoing since the winter of 2011-2012 within the McKenzie River Basin of the...