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Articles 1 - 16 of 16
Full-Text Articles in Engineering
Hydraulic Redistribution Under Saline Conditions, Josh Gottlieb
Hydraulic Redistribution Under Saline Conditions, Josh Gottlieb
Civil and Environmental Engineering Undergraduate Honors Theses
Water scarcity and soil salinity are dual stressors for plants in arid, salt-affected ecosystems. Hydraulic redistribution, a hydraulic adaptation which moves water through plant roots into dry or saline soil regions along potential gradients, aids plant survival in stressful environments. Recent theory regarding hydraulic redistribution proposes limitations on the process within saline soils. This study applies a minimalist resistor-capacitor model of the soil-plant-atmosphere system to the experimental conditions of a 2010 study investigating hydraulic redistribution in a salt affected area. The effectiveness of the model is evaluated, and a sensitivity analysis is conducted to identify key dynamics affecting the moisture …
The Critical Energy Infrastructure (Cei) Hub: A Look Into The Seismic Fragility Of Oregon’S Fuel, Annecy Bal
The Critical Energy Infrastructure (Cei) Hub: A Look Into The Seismic Fragility Of Oregon’S Fuel, Annecy Bal
Civil and Environmental Engineering Undergraduate Honors Theses
This research evaluates the seismic vulnerability of the Critical Energy Infrastructure (CEI) Hub and the associated fuel repercussions for the expected 9.0 magnitude earthquake along the Cascadia Subduction Zone. The tanks in the CEI hub are analyzed based on size and content. The owners and secondary containment areas are discussed using the same parameters. Various analysis techniques are reviewed to determine the most appropriate seismic fragility estimate for the site. The seismic vulnerability is analyzed using fragility curves by Hazus, American Lifeline Alliance, and D'Amico. The fragility curves are applied to the CEI Hub to determine expected damage and the …
Distributionally Robust Optimization Utilizing Facility Location Problems, Elijah Kling
Distributionally Robust Optimization Utilizing Facility Location Problems, Elijah Kling
Civil and Environmental Engineering Undergraduate Honors Theses
Facility location problems are used in widespread application in transportation, freight, supply chain, and logistics problems. Models can be developed as deterministic, where all parameters are known, or robust, where a parameter has uncertainty. This thesis explores a new method for developing robust formulation and compares the implications of assuming values for this uncertain parameter. Two models are solved, and both are compared against their deterministic counterparts using numerical analysis. By manipulating the input parameters and considering real world implications of the solutions, either the robust or deterministic can show better performance.
Maximum Coverage Facility Location Drone Routing Problem With Multiple Trip Stops, Marie Roza
Maximum Coverage Facility Location Drone Routing Problem With Multiple Trip Stops, Marie Roza
Civil and Environmental Engineering Undergraduate Honors Theses
Integer linear optimization can be used to formulate routing problems as models to find optimal solutions given a set of inputs and constraints. In this research, Chauhan et al.'s publication, "Maximum coverage capacitated facility location problem with range constrained drones," is expanded upon by modeling a facility location problem with two-to-one drone deliveries. The model analyzes a set of potential facilities that are available to meet the demands of a set of demand points. The drone delivery routes are modeled with the assumption that each opened facility is assigned one drone that can fulfill up to two demand points’ demands …
Cei Hub Failure Following A Cascadia Earthquake Event: Preliminary Modeling Of A Liquid Fuel Spill In The Lower Willamette And Columbia Rivers, Mike Du Bose
Civil and Environmental Engineering Undergraduate Honors Theses
The Critical Energy Infrastructure (CEI) Hub in Northwest Portland, OR spans a six-mile stretch of the Lower Willamette River and stores 90% of Oregon’s liquid fuel supply and 100% of the jet fuel for PDX. The CEI Hub is also built entirely on liquefiable soils which are likely to fail during a Cascadia earthquake event. The purpose of this project was to model a liquid fuel spill in the Lower Willamette and Columbia Rivers using the CE-QUAL-W2 model. Several scenarios were developed to account for different environmental conditions, (e.g., high and low discharge years) and varying spill durations (e.g., rapid …
Precipitation Impacts On Groundwater Levels In The Ephemeral Holgate Lake: A Modflow Inquiry, Amory Cervarich
Precipitation Impacts On Groundwater Levels In The Ephemeral Holgate Lake: A Modflow Inquiry, Amory Cervarich
Civil and Environmental Engineering Undergraduate Honors Theses
Holgate Lake, an ephemeral lake located in southeast Portland, has a history of flooding and inundating residential areas. The appearance of the lake is hypothesized to be a function of precipitation-driven changes in groundwater levels. A model was developed using MODFLOW-NWT, a U.S. Geological Survey (USGS) modular hydrologic program, to analyze parameters contributing to the appearance of the lake. The model was most sensitive to changes in aquifer properties including hydraulic conductivity and storativity. The model displayed low sensitivity to changes in precipitation, evapotranspiration, and conductance of surface waters. Results from the analysis contribute to a better understanding of the …
Elution Tailing Of Nonaqueous Phase Liquids In Porous Media, Louisa Orr
Elution Tailing Of Nonaqueous Phase Liquids In Porous Media, Louisa Orr
Civil and Environmental Engineering Undergraduate Honors Theses
A variety of porous media were studied to characterize contaminant dispersion over time. This work looked at a compilation of previously published studies to investigate the dependence of long term elution tailing trends on particular soil characteristics. Recession curve analysis was conducted on existing dispersed contaminant literature, to yield the low-concentration recession constant (K). The R2 values correlating the soil properties to contaminant concentration ranged from 0.12494 to 0.95429. The low-concentration recession constant (K) values ranged from 0.9745407 0.9999988. The relationship between K and the soil properties porosity, organic carbon, and fines fraction is increasing. Bulk density and the …
Torrefaction Kinetics Of Hemp Hurds, An Emerging Agricultural Byproduct, In A Small Retort, Tel Jensen
Torrefaction Kinetics Of Hemp Hurds, An Emerging Agricultural Byproduct, In A Small Retort, Tel Jensen
Civil and Environmental Engineering Undergraduate Honors Theses
As knowledge concerning the consequences of unsustainable energy sources and agricultural practices grows, development of low-impact alternatives to both becomes more important. Sustainable sources of biomass offer solutions to both problems. This study characterized the reaction kinetics of torrefying an agricultural byproduct, the woody interior of hemp stems, or hurds. Torrefaction was carried out at 250 °C in small and simple retorts made of galvanized steel pipe. A first-order model most closely approximated the reaction. A sensitivity analysis was performed and the data was adjusted to correct for three potential sources of error, and regressed to find the best fit …
A Statistical Investigation Of Lower Columbia River Water Temperature, 1915-2003, Corina Christina Mae Overman
A Statistical Investigation Of Lower Columbia River Water Temperature, 1915-2003, Corina Christina Mae Overman
Civil and Environmental Engineering Undergraduate Honors Theses
The Columbia River is home to anadromous salmon populations that migrate upriver every year to spawn. These fish require cool water temperatures (Tw) to survive. In recent years, high summer Tw in the Columbia River has caused increased mortality of salmon. Different possible explanations for increased Tw include climate change, deforestation, and decreased summertime streamflow (Q) due to dams. In this study, robust linear regression models of Tw based on air temperature (Ta) and Q were developed to examine the change in Tw over time. The data was …
Rate-Limited Mass Transfer Of Trichloroethene, Deza R. Irving
Rate-Limited Mass Transfer Of Trichloroethene, Deza R. Irving
Civil and Environmental Engineering Undergraduate Honors Theses
Trichloroethene (TCE) is a volatile and toxic contaminant commonly found in the subsurface. To help reduce the effects of this contaminant, it is important to understand the transport and fate behavior of TCE through the subsurface. As groundwater fills the void spaces of a porous media contaminated with pure-phase TCE, the TCE will dissolve into the water, contaminating the groundwater. It was expected that this dissolution would follow a first-order mass transfer process, suggesting that the rate of dissolution of TCE is dependent on the mass of TCE present in solution. The purpose of this study was to characterize the …
Emerging Pollutants In The Columbia River: A Simple Assessment Of Nonpoint Source Zones, Chulgi Kim
Emerging Pollutants In The Columbia River: A Simple Assessment Of Nonpoint Source Zones, Chulgi Kim
Civil and Environmental Engineering Undergraduate Honors Theses
Water quality modeling in the Columbia River Basin was conducted at the confluence of the Willamette and Columbia Rivers, river mile 101. The study area for this research consists of Sauvie Island, OR, and the surrounding areas of Vancouver, WA. Analysis of the region’s watershed and simple hydrologic calculations allowed for estimates of potential sources contributing to PBDEs in the Columbia River along river mile 101. This research included assessment of rainfall patterns and peak discharge rates in the areas along the rivers. A simple model of overland flow for the watershed was applied to estimate the area’s contribution to …
Preliminary Design Guidelines For Poraver-Based Lightweight Concrete, Marlow Stanton
Preliminary Design Guidelines For Poraver-Based Lightweight Concrete, Marlow Stanton
Civil and Environmental Engineering Undergraduate Honors Theses
This research project investigated lightweight Portland cement concrete batching procedures and developed guidelines for designing Poraver-based mixes. Lightweight concrete has a variety of applications, from structural fills to structural members. The study was completed in two stages: Stage 1 was a pilot study serving to confirm whether the ACI211.2-98 Volumetric Method was appropriate for Poraver-based lightweight concrete. Additionally, Stage 1 examined the range of outcomes possible with a large combination of test mixes and explored handling techniques for presoaked aggregate. Stage 2 focused on confirming the linear relationship of cement content and compressive strength through a large quantity of test …
Small-Scale Minimal-Maintenance Anaerobic Digestion Of Food Waste For Solids Reduction And Methane Production: Feasibility Study, Leland C. Scantlebury
Small-Scale Minimal-Maintenance Anaerobic Digestion Of Food Waste For Solids Reduction And Methane Production: Feasibility Study, Leland C. Scantlebury
Civil and Environmental Engineering Undergraduate Honors Theses
Six gallons of food waste was anaerobically digested for 76 days in two small-scale digesters sitting by a lab window. The main difference, besides waste sources, of these digesters was substrate processing: chopping versus blending. An effort was made to minimize the maintenance of the digesters, however, after 45 days of overly acidic (pH
Benchtop Minimal-Intervention Anaerobic Digestion Of Vegetarian Food Waste For Ph And Methane Production: Conceivability And Control Study, Emily J. Heleva-Ponaski
Benchtop Minimal-Intervention Anaerobic Digestion Of Vegetarian Food Waste For Ph And Methane Production: Conceivability And Control Study, Emily J. Heleva-Ponaski
Civil and Environmental Engineering Undergraduate Honors Theses
Cities around the world transport large quantities of waste to landfills at a great expense to their residents, infrastructures, and environments. The objective of this study was to run an anaerobic food waste digester with minimal interference or maintenance. One specific goal of this research was to evaluate the relationship between anaerobic food waste and pH. Two benchop digesters were started with vegetarian food waste collected from the Portland State University campus. Measurements were collected over the course of the digestion process. Due to low pH and lack of biogas production, the digesters were buffered with sodium carbonate and seeded …
The Effect Of The Bicycle Detector Symbol And R10-22 Sign On Cyclist Queuing Position At Signalized Intersections, Stefan W. Bussey
The Effect Of The Bicycle Detector Symbol And R10-22 Sign On Cyclist Queuing Position At Signalized Intersections, Stefan W. Bussey
Civil and Environmental Engineering Undergraduate Honors Theses
The Manual of Traffic Control Devices (MUTCD) includes a roadway marking and accompanying explanatory sign which may be installed on public roads to help guide cyclists position themselves over detection at actuated traffic signals. While adopted into the MUTCD in 2003, little research is available on the effectiveness of the marking and sign. This study evaluates the influence that the roadway marking, roadway marking installed in conjunction with the explanatory sign, and an alternative detector marking comprised of the MUTCD marking installed over a one foot by two feet green rectangle, have on cyclist queuing position at actuated, signalized intersections. …
Carbon Sponsoring: A New Idea In Personal Carbon Trading, Direct Carbon Offset Pledges For Travel, Alexander Y. Bigazzi
Carbon Sponsoring: A New Idea In Personal Carbon Trading, Direct Carbon Offset Pledges For Travel, Alexander Y. Bigazzi
Civil and Environmental Engineering Undergraduate Honors Theses
Public and political consensus expresses the need for broad action to mitigate climate change. To this end, different forms of carbon trading exist to initiate carbon reduction projects. This thesis proposes the idea of carbon sponsoring, a new tool for personal carbon trading. Unlike carbon offsets, the main option for individuals wishing to mitigate their carbon footprint, carbon sponsoring is a purely social instrument involving carbon-reducing pledges. Carbon sponsoring is intended for individuals who seek immediate, direct carbon offsets for their personal emissions. It is not meant as a broad tool correcting the various deficiencies of the carbon trading markets, …