STEM education is delivered to K12 audiences by Pre-college Programs across the nation, many of which serve underrepresented and underserved students as part of their core missions. While there is robust attention to STEM curriculum development and college connection events in such programs, few have social-cultural aspects of learning as...
Phytochemicals from the genus, Fagonia, have been attracting increasing attention due to their potential beneficial effects on human health, particularly, anti-cancer properties. Certain Fagonia species contain various types of phytochemicals such as saponins, alkaloids, cardiac glycosides, flavonoids, terpenoids, and tannins. In this study, we investigated the phytochemical composition of a...
The current American free-roaming horse (Equus caballus) population far exceeds the appropriate population limit set by the Bureau of Land Management (BLM) to preserve resources on public lands. Several techniques have been tested to assist in decreasing repopulation rates. The purpose of the present study was to analyze two contraceptive...
In order to reduce the cost of lignocellulosic ethanol production, a model was previously developed to predict the amount of fermentable sugar released based on parameters concerning both biomass and enzymes. To validate this model, enzymatic hydrolysis must be carried out using individual purified cellulase enzymes. Endo-1,4-β-D-glucanase I (EG I),...
Cascadia’s 1700 earthquake generated a tsunami and widespread subsidence along Pacific Northwest coastline. The tsunami deposited sandy sediments in many Oregon coastal estuaries, such as Alsea Bay. Although the recurrence of subduction-generated megathrust earthquakes and tsunami events in this region are recorded in the stratigraphy, knowledge of the full inland...
The details of the 1700 Cascadia Subdction Zone earthquake and tsunami can be better constrained using data from tsunami sand sheets, provided knowledge of the waveform, estuary geometry and bed roughness controls on the deposition pattern of the sand sheet. In this study, we use the hydrodynamic and sediment transport...
Cyanophage are viruses that infect cyanobacteria, photosynthetic microorganisms which are known to produce several anticancer and antibacterial chemical compounds. Cyanophage are significant members of microbial communities in marine and freshwater environments. There has been significant difficulty inventorying marine and freshwater cyanophage, however, due to the difficulty in cultivating their hosts....
Understanding charge transfer in organic semiconductors is important for developing devices like organic light emitting diodes and flexible electronics. Optical tweezers have been used in many disciplines for trapping, manipulating, and analyzing microscopic objects such as microspheres, micro-organisms, and other colloidal particles. Using optical tweezers, studies have measured the average...
Kinesins are intracellular motor proteins that transform chemical energy into mechanical energy through ATP hydrolysis to move along microtubules. Kinesin roles can vary among transportation, regulation, and spindle alignment within most cells. Many kinesin have been found to move towards the plus end of microtubules
at a steady velocity. For...
This study examines how students were interacting with pre-lecture videos via the BoxSand website. Students of the Fall 2015 and Fall 2016 introductory physics courses at Oregon State University were studied. The course was taught as a flipped classroom in which the instructional material was provided via BoxSand. BoxSand is...
Understanding the electrical transport properties of graphene provides a basis for determining its future as a potential semiconducting device that can be used for the next generation of transistors and photodetectors. Graphene p-n junctions can also function as field effect transistors, and thus are a logical starting point for I-V...
We developed an integration-based line detection algorithm. Existing line detection methods such as the Hough Transformation (HT) and its variants are insensitive to image noise. The reason is that HT finds lines by calculating the gradient of the image and assumes that the region where the gradient is the steepest...
Carbon nanotubes are the subject of intense interest in virtually every field, from medicine to nano-scale electrical components. Multi-walled nanotubes exhibit a strong nonlinear response to high-field strength terahertz radiation. This research uses terahertz pulses with field strength exceeding 1 MV/cm generated by means of optical rectification utilizing a lithium...
Fractal visual hashes have the potential to replace traditional hexadecimal hashes for SSH applications with the goal of increasing user recognition of identities of remote computers. Rather than rely on human users manually comparing two hexadecimal hashes as part of SSH's public-private key encryption process, users would compare fractal images...
This thesis looks at the third harmonic voltage response of a small incandescent lightbulb. The third harmonic voltage, or 3 omega (3ω) voltage, arises from applying a 1ω sinusoidal voltage across a resistive material. The 3ω voltage carries with it information about the thermal conductivity of the material. A lock-in-amplifier...
A method for determining bandgap energy using diffuse reflection is presented. The method uses bifurcated fiber optic cables to measure the diffuse reflection of diffusely reflective materials. The absorption spectrum is extrapolated from the diffuse reflection spectrum and used to determine the bandgap of powdered materials. The theory of nonspecular...
Pollination is a critical ecosystem function for sustaining biodiversity. However, pollinators and the services they provide are threatened by landscape-altering anthropogenic activities across the globe. Habitat loss and fragmentation, introduction of invasive species, chemical use, and urbanization have been shown to impact pollination. Pollinator foraging behavior is thought to be...
The common choice in computational approximations, from 0 K to room temperature, of solid materials is to assume the structure remains unchanged at low temperatures. Often such an approximation is a very reasonable assumption. However, this approximation is not absolute and can break down even for relatively simple materials such...
The Min protein system in Escherichia coli helps the cell division process by identifying the center of the cell [1, 7]. This system has been modeled succesfully computationally under standard conditions. There has been recent experimental interest in the cell division process for significantly perturbed cell shapes. We take the...
Coronagraphs have been used on telescopes for many years to block out bright
sources in the sky to allow nearby objects to be resolved. A digital micromirror
array (DMA) can be used in the focal plane of a telescope to serve as an adaptive
coronagraph. The DMA can be configured...
We present a report on a new capability for low temperature microscopy of organic
optoelectronic semiconductor materials. We may now perform photoluminescence (PL) and
conductivity measurements as a function of temperature on a microscopic level.
Testing confirmed the setup's ability to support microscopic measurements at pressures
of 10^-6 Torr and...
Studying the evolution of the Milky Way galaxy helps us understand our place in the Universe. Early evolution of the Galaxy can effectively be studied by observing stars with low metallicity values since they are the oldest stars still visible. Due to the formation of the Galaxy, the oldest stars...
Forward osmosis provides a low energy alternative for waste water purification. One of the major issues facing this process is the formation of a foulant layer preventing fluid transfer across the membrane. In recent studies, a conductive layer added to the membrane surface allowing an electric charge to be present...
This investigation expands on earlier methods of using surface polarization reflection (SPR) to characterize the first few monolayers of a surface. Past research measured intensities of light reflecting off an SiO₂ optical flat inside a vacuum. Pressure of applied gas was changed to view a change in reflection. In an...
Optical trapping is a tool used throughout a wide variety of disciplines rang- ing from precisely probing and manipulating sub-micron organisms in biol- ogy to analyzing fundamental charge transfer in colloidal physics. This thesis presents research involving optical tweezer force measurements of polystyrene and silica microspheres. In addition, preliminary work...
This project investigated transient photoconductivity in organic donor-acceptor (D-A) systems, where a flourinated anthradithiophene, ADT-TES-F, acts as the donor. Various acceptor molecules were used, with different sidegroups, and different HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energy level offsets relative to the acceptor. Thin film composites...
While metaphysical turmoil is the essential human problem in T.S. Eliot’s “The Waste Land,” “The Love Song of J. Alfred Prufrock” and “Preludes,” traditional criticism of the poems relegates the physical world to a merely rhetorical role. This thesis argues that Eliot’s use of objects in his poetry suggests they...
High resolution images of a dim companion in a binary star system can be obtained using a Digital Micromirror Array (DMA) as an optical mask. Imaging can be problematic because the intense light from the main star can saturate the detector and leave the companion unnoticed. Placement of the DMA...
This thesis presents a measurement of the resonance integral and thermal cross section – which together represent the total neutron absorption cross section – of the naturally occurring isotopes of platinum that emit gamma radiation upon neutron absorption. The measurements were made via neutron activation analysis. Platinum samples were bombarded...
An apparatus and method for calibrating planar laser induced fluorescence using a two-dye, two-color method was developed. A laser sheet was expanded from a 473 nm laser to excite dye solutions into higher energy states then fluoresced through spontaneous emission. The two fluorescent dyes selected for research and development were...
The neutron capture cross sections of ¹⁰⁶Cd, ¹⁰⁸Cd, ¹¹⁰Cd, ¹¹²Cd, ¹¹⁴Cd and ¹¹⁶Cd were determined in the present project. Four different OSU TRIGA reactor facilities were used to produce redundancy in the results and to measure the thermal cross section and resonance integral separately. When the present values were compared...