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...