Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Computer Sciences (15)
- Environmental Sciences (11)
- Engineering (8)
- Chemistry (7)
- Oceanography and Atmospheric Sciences and Meteorology (7)
-
- Earth Sciences (6)
- Electrical and Computer Engineering (6)
- Climate (4)
- Life Sciences (4)
- Physics (4)
- Geology (3)
- Other Computer Sciences (3)
- Social and Behavioral Sciences (3)
- Systems Architecture (3)
- Artificial Intelligence and Robotics (2)
- Ecology and Evolutionary Biology (2)
- Education (2)
- Electrical and Electronics (2)
- Environmental Monitoring (2)
- Fresh Water Studies (2)
- Glaciology (2)
- Medical Sciences (2)
- Medicine and Health Sciences (2)
- Natural Resource Economics (2)
- Oil, Gas, and Energy (2)
- Other Chemistry (2)
- Other Environmental Sciences (2)
- Soil Science (2)
- Sustainability (2)
- Keyword
-
- Digital (3)
- Semiconductor nanoparticles (2)
- Acoustic imaging (1)
- Actinobacteria (1)
- Air quality -- Measurement (1)
-
- Altered hydrology (1)
- Amphibians -- Habitat -- Oregon -- Portland Metropolitan Area (1)
- Aquifers -- Oregon -- Florence (1)
- Arsenic (1)
- Artwork (1)
- Asian American women college teachers -- Oregon -- Biography (1)
- Atmospheric methane -- Observations (1)
- Automobiles -- Motors -- Exhaust gas -- Measurement (1)
- Azide (1)
- Benzotnazoles (1)
- Benzyne (1)
- Biodiesel fuels -- Environmental aspects (1)
- Biophysics (1)
- Biosynthesis (1)
- Brain (1)
- Business process (1)
- Cadmium selenide (1)
- Calcretes -- Pacific Northwest (1)
- Cascade Range (1)
- Catalytic RNA (1)
- Cesm (1)
- China -- History -- Republic (1912-1949) (1)
- Chinese American businesspeople -- Oregon -- Biography (1)
- Climatic changes (1)
- Climatic changes -- Environmental aspects -- Oregon -- Molalla River Watershed (1)
Articles 1 - 30 of 45
Full-Text Articles in Physical Sciences and Mathematics
Use Of International Hydrographic Organization Tidal Data For Improved Tidal Prediction, Songwei Qi
Use Of International Hydrographic Organization Tidal Data For Improved Tidal Prediction, Songwei Qi
Dissertations and Theses
Tides are the rise and fall of water level caused by gravitational forces exerted by the sun, moon and earth. Understanding sea level variation and its impact currents is very important especially in coastal regions. With knowledge of the tide-generating force and boundary conditions, hydrodynamic models can be used to predict or model tides in coastal regions. However, these models are not sufficiently accurate, and in-situ tide gauge data may be used to improve them in coastal regions. The International Hydrographic Organization (IHO) tidal data bank consists of over 4000 tide gauge stations scattered all around the globe, most of …
Stream-Associated Amphibian Habitat Assessment In The Portland-Vancouver Metropolitan Region, Andrew Evans Dietrich
Stream-Associated Amphibian Habitat Assessment In The Portland-Vancouver Metropolitan Region, Andrew Evans Dietrich
Dissertations and Theses
This study assessed the influence of landscape development on stream-associated amphibians in forested riparian areas within the Portland-Vancouver metropolitan region. Human alteration of landscapes may dramatically affect the ecology of neighboring aquatic systems. It was hypothesized that lotic amphibians would be negatively associated with greater amounts of landscape development and positively associated with forested area within the surrounding watershed. Thirty-seven 1st-3rd order streams were sampled between June 21st and September 21st in 2011. Streams potentially providing adequate habitat for stream-obligate amphibians were randomly selected. Amphibians were surveyed along 30-meter stream transects using an active-cover search (ACS). Environmental variables associated with …
Characterization Of The Red Bluff Landslide, Greater Cascade Landslide Complex, Columbia River Gorge, Washington, James Robert Randall
Characterization Of The Red Bluff Landslide, Greater Cascade Landslide Complex, Columbia River Gorge, Washington, James Robert Randall
Dissertations and Theses
Located in the Columbia River Gorge, The Red Bluff Landslide (18.8 km2) is one of four large landslides that make up the Cascade Landslide Complex. In its current form, the Red Bluff Landslide is a post-Missoula Flood feature made up of two components: an active upper lobe (8.6 km2) that is translational, creeping to the south at 25 cm/yr and spreading laterally to the east at 6 cm/yr over a semi-fixed portion (10.2 km2) of the Red Bluff Landslide area that has been "smoothed" by Missoula Floods. The upper active lobe is the landslide debris accumulated since Missoula Flood time …
An Investigation Of Urban Mobile Source Aerosol Using Optical Properties Measured By Crdt/N: Diesel Particulate Matter And The Impact Of Biodiesel, Monica Elizabeth Wright
An Investigation Of Urban Mobile Source Aerosol Using Optical Properties Measured By Crdt/N: Diesel Particulate Matter And The Impact Of Biodiesel, Monica Elizabeth Wright
Dissertations and Theses
Mobile source emissions are a major contributor to global and local air pollution. Governments and regulatory agencies have been increasing the stringency of regulations in the transportation sector for the last ten years to help curb transportation sector air pollution. The need for regulations has been emphasized by scientific research on the impacts from ambient pollution, especially research on the effect of particulate matter on human health. The particulate emissions from diesel vehicles, diesel particulate matter (DPM) is considered a known or probable carcinogen in various countries and increased exposure to DPM is linked to increased cardiovascular health problems in …
Site Selection By Migratory Shorebirds In Oregon Estuaries Over Broad And Fine Spatial Scales, Aileen Kilpatrick Miller
Site Selection By Migratory Shorebirds In Oregon Estuaries Over Broad And Fine Spatial Scales, Aileen Kilpatrick Miller
Dissertations and Theses
Many migratory shorebirds rely on estuaries as stop-over sites to refuel during migration, and the loss of stop-over sites is a primary threat to shorebird populations on the West Coast of the United States (e.g. Calidris alpina pacifica, C. mauri). Conservation and research has focused on the largest of these sites; however, smaller estuaries also host thousands of migratory shorebirds. Furthermore, the reasons for site selection are largely unknown. Estuarine inter-tidal microhabitats are non-uniform and both abiotic and biotic factors may serve as predictors of whether an abundance of shorebirds will use a site. I investigated shorebird site selection on …
Inventory And Initiation Zone Characterization Of Debris Flows On Mount St. Helens, Washington Initiated During A Major Storm Event In November, 2006, Keith Vinton Olson
Inventory And Initiation Zone Characterization Of Debris Flows On Mount St. Helens, Washington Initiated During A Major Storm Event In November, 2006, Keith Vinton Olson
Dissertations and Theses
The heavy precipitation event of November 3-8, 2006 dropped over 60 cm of rain onto the bare southern slopes of Mount St. Helens and generated debris flows in eight of the sixteen drainages outside the 1980 debris avalanche zone. Debris flows occurred on the upper catchments of the Muddy River, Shoestring Glacier, Pine Creek, June Lake, Butte Camp Dome, Blue Lake, Sheep Creek, and South Fork Toutle River. Debris flows were clustered on the west and south-east sides of the mountain. Of the eight debris flows, three were initiated by landslides, while five were initiated by headward or channel erosion. …
Investigating The Holocene History Of Eliot Glacier, Mount Hood, Oregon, Nadia Sittara Jones
Investigating The Holocene History Of Eliot Glacier, Mount Hood, Oregon, Nadia Sittara Jones
Dissertations and Theses
This research documents the Holocene glacial history of Mount Hood, Cascade Mountains, Oregon by analyzing a set of three lateral moraines abutting Eliot Glacier, the largest glacier on the mountain. This study seeks to: 1) establish the relative ages of these lateral moraines and 2) determine if these features represent distinct glacial advances. The hypothesis is that the lateral moraines for Eliot Glacier represent three distinct periods of glacial advance based on their position relative to the current glacier and other diagnostic indicators. Soil profiles of three positions (shoulder, backslope, and footslope) on the distal side of each lateral moraine …
The Role Of Habitat Restoration And Conservation In The Changing Socio-Economic Conditions Of Grant County, Oregon, Kristen Lauren Senkyr
The Role Of Habitat Restoration And Conservation In The Changing Socio-Economic Conditions Of Grant County, Oregon, Kristen Lauren Senkyr
Dissertations and Theses
Habitat restoration has socio-economic as well as biophysical impacts. In Grant County, Oregon a recent influx of funding and technical resources for habitat restoration has led to focused monitoring efforts there to better understand the impacts. This study explores how local land use and land management practices are changing in Grant County as a result of restoration and other drivers. In-depth interviews were conducted with 17 landowners, land managers, and long time residents to document the change they have observed and identify how they are adapting. The results suggest that many interconnected social, economic, and ecological changes have taken place …
Application Of Inter-Die Rank Statistics In Defect Detection, Vivek Bakshi
Application Of Inter-Die Rank Statistics In Defect Detection, Vivek Bakshi
Dissertations and Theses
This thesis presents a statistical method to identify the test escapes. Test often acquires parametric measurements as a function of logical state of a chip. The usual method of classifying chips as pass or fail is to compare each state measurement to a test limit. Subtle manufacturing defects are escaping the test limits due to process variations in deep sub-micron technologies which results in mixing of healthy and faulty parametric test measurements. This thesis identifies the chips with subtle defects by using rank order of the parametric measurements. A hypothesis is developed that a defect is likely to disturb the …
Ancient Cataclysmic Floods In The Pacific Northwest: Ancestors To The Missoula Floods, Erica Medley
Ancient Cataclysmic Floods In The Pacific Northwest: Ancestors To The Missoula Floods, Erica Medley
Dissertations and Theses
Ancient Cataclysmic Floods were the Ice Age Floods that left erosional and depositional features and preceded the Missoula Floods (15-18,000 ka) in the Pacific Northwest of the United States (Allen et al., 2009). All previously studied ancient sites were visited (14) and new sites (11) were found; four Missoula Flood quarries were also visited; a total of 29 sites were studied in this thesis. The use of calcrete paleosols to provide relative age dates for flood deposits was analyzed in this thesis. Missoula Flood gravel pits were sampled in order to examine the degree of calcrete development in flood deposits …
Where Is The Rain-On-Snow Zone In The West-Central Washington Cascades?: Monte Carlo Simulation Of Large Storms In The Northwest, Matthew John Brunengo
Where Is The Rain-On-Snow Zone In The West-Central Washington Cascades?: Monte Carlo Simulation Of Large Storms In The Northwest, Matthew John Brunengo
Dissertations and Theses
Rain-on-snow (ROS) occurs when warm, wet air moves into latitudes and/or elevations having vulnerable snowpacks, where it can alter water inputs to infiltration, runoff and erosion. The Pacific Northwest is particularly susceptible: winter storms off the Pacific cause locally heavy rain plus snowmelt almost annually, and disastrous flooding and landsliding intermittently. In maritime mountainous terrain, the effects seem more likely and hydrologically important where warm rains and seasonal snowpacks are liable to coincide, in middle elevations. Several questions arise: (1) In the PNW, does ROS affect the long-term frequency and magnitude of water delivery to the ground, versus total precipitation …
Developing A Comprehensive Software Toolkit For Creating Digital Mosaic Artwork, Dmitry Bosikov
Developing A Comprehensive Software Toolkit For Creating Digital Mosaic Artwork, Dmitry Bosikov
Dissertations and Theses
No abstract provided.
Re-Engineering Ccny's Business Process Of The Non-Tax Levy Disbursements Requisitions, Ferguson Rodley
Re-Engineering Ccny's Business Process Of The Non-Tax Levy Disbursements Requisitions, Ferguson Rodley
Dissertations and Theses
No abstract provided.
Rapid Decoding Of Digital Data Streams Using Field Programmable Gate Arrays, Andrew Hernandez
Rapid Decoding Of Digital Data Streams Using Field Programmable Gate Arrays, Andrew Hernandez
Dissertations and Theses
No abstract provided.
Context Awareness And Discovery For Helping The Blind, Martin Goldberg
Context Awareness And Discovery For Helping The Blind, Martin Goldberg
Dissertations and Theses
No abstract provided.
Azide-Benzyne Cycloaddition And Olefination To Vinyl Benzotriazoles, Singh Govindra
Azide-Benzyne Cycloaddition And Olefination To Vinyl Benzotriazoles, Singh Govindra
Dissertations and Theses
No abstract provided.
Studies On Sucralose-Based Low Molecular Weight Gelators, Malick Samateh
Studies On Sucralose-Based Low Molecular Weight Gelators, Malick Samateh
Dissertations and Theses
Amphiphiles are molecules with both hydrophilic head and hydrophobic tail groups. Examples of amphiphiles include surfactants, detergents, soaps, bile acids/salts and lipids. Due to their amphiphilic nature, they tend to self-assemble in solution via non-covalent interactions such as hydrogen-bonding, π-π stacking and donor–acceptor interactions to form hierarchical morphologies like micelles, lamellae and fibers. The ones capable of subsequently forming gels are known as low molecular weight gelators (LMWGs). LMWGs usually form “polymer-like” fibers that interact to form a three-dimentional network known as a Self-Assembled Fibrillar Network (SAFIN), which entraps and immobilizes the entire solvent pool to form a viscoeslatic material …
Effects Of Arsenic And Uvb Radiation On Induction Of Cyclin D1 In Human Keratinocytes., Julian Gonzalez
Effects Of Arsenic And Uvb Radiation On Induction Of Cyclin D1 In Human Keratinocytes., Julian Gonzalez
Dissertations and Theses
Arsenic and Ultraviolet radiation B (UVB) are environmental toxins that have been linked to various epithelial cancers. Arsenic metabolism in humans leads to its collection in the skin, where it encounters and can act with known carcinogen UVB. Epidemiological evidence of the two toxins demonstrates their potential to affect signaling pathways, with various consequences. Here we employ an in vitro model system using Normal Human Epidermal Keratinocytes (NHEK) to identify the effect of arsenic and UVB on humans and whether they work synergistically. We find that although both cause induction of cyclin D1, culturing cells with both co-mutagens does not …
Multimedia Content-Based Indexing And Recognition In Digital Libraries, Steven Medina
Multimedia Content-Based Indexing And Recognition In Digital Libraries, Steven Medina
Dissertations and Theses
"Recognition of digital media is more prevalent in today’s computer culture than ever before. The advent of low cost storage has created a seemingly infinite amount of metadata on the internet, as well as on local machines throughout the world. It is more important than ever to have the capability of quickly and accurately filtering this metadata to find a desired result. Data can be searched using various criteria. For example, text data is searched by analyzing the contents of the text itself. One might execute a search using a method as simple as looking for the ASCII file name, …
Parallel Trie-Based Frequent Itemset Mining On Graphics Processors, Jay Junjie Yao
Parallel Trie-Based Frequent Itemset Mining On Graphics Processors, Jay Junjie Yao
Dissertations and Theses
No abstract provided.
Understanding The Emission From Semiconductor Nanoparticles, Beth Ann Manhat
Understanding The Emission From Semiconductor Nanoparticles, Beth Ann Manhat
Dissertations and Theses
This dissertation describes the synthesis and characterization of fluorescent semiconductor nanoparticles (NPs) in order to optimize their biomedical utility for imaging and sensing applications. While both direct and indirect bandgap semiconductor NPs have been studied, control over their emission properties vary. Quantum confinement (QC), which primarily controls the emission wavelength of nanosized semiconductors, dictates that as the size of semiconductor NPs decrease, the magnitude of the bandgap increases, resulting in changes in the observed emission wavelength: smaller NPs have a larger bandgap, and thus a bluer emission. However, surface, interfacial, or shell defects can act as non-radiative or radiative recombination …
Shaping The Future Past: Finding History, Creating Identity In The Kwan Hsu Papers, Lisa Chere' Donnelly
Shaping The Future Past: Finding History, Creating Identity In The Kwan Hsu Papers, Lisa Chere' Donnelly
Dissertations and Theses
Dr. Kwan Hsu was neither a superstar nor a celebrity. Her name does not come up in conversations about important contributors to her field of biophysics nor is she instantly recognizable for her contributions to Portland State University's international program or the state of Oregon's business ties with China. Yet she was a contributor, a cog-in-the-wheel, at the very least, in all of these areas and more. She was a peripheral member of a well-known Chinese family, but few in the United States know of or perhaps have interest in, but otherwise, she had no great connections or family ties …
Evolved Design Of A Nonlinear Proportional Integral Derivative (Npid) Controller, Shubham Chopra
Evolved Design Of A Nonlinear Proportional Integral Derivative (Npid) Controller, Shubham Chopra
Dissertations and Theses
This research presents a solution to the problem of tuning a PID controller for a nonlinear system. Many systems in industrial applications use a PID controller to control a plant or the process. Conventional PID controllers work in linear systems but are less effective when the plant or the process is nonlinear because PID controllers cannot adapt the gain parameters as needed. In this research we design a Nonlinear PID (NPID) controller using a fuzzy logic system based on the Mamdani type Fuzzy Inference System to control three different DC motor systems. This fuzzy system is responsible for adapting the …
Groundwater Surface Trends In The North Florence Dunal Aquifer, Oregon Coast, Usa, Sarah Rebecca Doliber
Groundwater Surface Trends In The North Florence Dunal Aquifer, Oregon Coast, Usa, Sarah Rebecca Doliber
Dissertations and Theses
The North Florence Dunal Aquifer is the only feasible source for drinking water for the coastal city of Florence, Oregon and Florence's Urban Growth Boundary. High infiltration rates and a shallow groundwater table leave the aquifer highly susceptible to contamination from septic tank effluent, storm runoff, chemical fertilizers and recreational ATV use throughout the dunes. Public interest in the quality and quantity of the aquifer water has been sparked since the City of Florence received a grant from the Environmental Protection Agency for a watershed protection and restoration project. Delineation of the shallow groundwater surface and its relationship to the …
Understanding Sand Mining On The Maha Oya: The Conflict Between Economic And Environmental Survival, Meredith Corea Talbert
Understanding Sand Mining On The Maha Oya: The Conflict Between Economic And Environmental Survival, Meredith Corea Talbert
Dissertations and Theses
River sand mining from the Maha Oya is the main source of income and a force that drives economic activity for residents along the river. This study takes place in Sri Lanka, there are three villages included in this project: Jambugaswatte, Janituspuraya and Thoppuwa. In Sri Lanka, sand serves as the main building material. It is used to make bricks, tiles, asphalt and concrete, therefore demanding a high market value. However, the over-extraction of sand comes along with significant environmental problems. These communities depend on the river in many ways and the health of the river directly corresponds to the …
Community Earth System Model: Implementation, Validation, And Applications, William Christian Porter
Community Earth System Model: Implementation, Validation, And Applications, William Christian Porter
Dissertations and Theses
The Community Earth System Model (CESM) is a coupling of five different models which are combined to simulate the dynamic interactions between and within the Earth's atmosphere, ocean, land, land-ice, and sea-ice. In this work, the installation and testing of CESM on Portland State University's Cluster for Climate Change and Aerosol Research (CsAR) is described and documented, and two research applications of the model are performed. First, the improved treatment of cloud microphysics within recent versions of CESM's atmospheric module is applied to an examination of changes in shortwave cloud forcing (SWCF) and results are compared to output from older …
Development And Implementation Of Acoustic Feedback Control For Scanning Probe Microscopy, Rodolfo Fernandez Rodriguez
Development And Implementation Of Acoustic Feedback Control For Scanning Probe Microscopy, Rodolfo Fernandez Rodriguez
Dissertations and Theses
A remote-sensing acoustic method for implementing position control feedback in Scanning Probe Microscopy (SPM) is presented. The capabilities of this feedback control using the new Whispering Gallery Acoustic Sensing (WGAS) method is demonstrated in a Shear-force Scanning Probe Microscope that uses a sharp probe attached to a piezoelectric Quartz Tuning Fork (QTF) firmly mounted on the microscope's frame. As the QTF is electrically driven its mechanical response reaches the SPM frame which then acts as a resonant cavity producing acoustic modes measured with an acoustic sensor strategically placed on the SPM head. The novelty of the WGAS resides in using …
A Systems Approach To Ecological Economic Models Developed Progressively In Three Interwoven Articles, Takuro Uehara
A Systems Approach To Ecological Economic Models Developed Progressively In Three Interwoven Articles, Takuro Uehara
Dissertations and Theses
My dissertation develops and analyzes ecological economic models to study the complex dynamics of an ecological economic system (EES) and investigate various conditions and measures which can sustain a developing economy over the long term in view of resilience and sustainability. Because of the intrinsic complexity of the system, I take a systems approach, using economics as the foundation for the basic structure of an ecological economic model, and system dynamics as the method to build and analyze such a complex ecological economic model. Throughout my dissertation, the model developed by Brander and Taylor (1998) is adopted as a baseline …
Sustainability Education As A Framework For Enhancing Environmental Stewardship In Young Leaders: An Intervention At Tryon Creek Nature Day Camp, Andrea Nicole Lawrence
Sustainability Education As A Framework For Enhancing Environmental Stewardship In Young Leaders: An Intervention At Tryon Creek Nature Day Camp, Andrea Nicole Lawrence
Dissertations and Theses
UNESCO established Sustainability Education as a top priority when it declared 2005 - 2014 to be the global decade for sustainability. Sustainability education can be implemented in outdoor programs such as nature summer camps in order to build environmental stewardship and ecological literacy in counselors and campers. This study sought to determine the extent to which an ecology and leadership training given to assistant counselors at Tryon Creek State Natural Area day camp achieved the goals of sustainability education--for the assistant counselors to learn about ecology, develop stewardship attitudes and behaviors toward the environment, and become positive role models for …
Climate Change Effects And Water Vulnerability In The Molalla Pudding River Basin, Oregon, Usa, Susan Amelia Wherry
Climate Change Effects And Water Vulnerability In The Molalla Pudding River Basin, Oregon, Usa, Susan Amelia Wherry
Dissertations and Theses
Water management plans are typically developed using historical data records and historical return periods for extreme events, such as floods or droughts. Since these analyses of return periods typically assume a certain degree of stationarity (constant mean, standard deviation, distribution) in hydrologic variables, the potential future impacts of climate change are excluded. In developing water management plans, predicted changes to climate variables should be considered to evaluate the degree of non-stationarity that may exist in the future. In this way, regions most sensitive to climate change can be identified and managed appropriately. This study performed such a task by using …