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Portland State University

Theses/Dissertations

2017

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Articles 1 - 30 of 45

Full-Text Articles in Engineering

Microstructure And Mechanical Properties Of Additive Manufacturing Titanium Alloys After Thermal Processing, Ahmet Alptug Tanrikulu Dec 2017

Microstructure And Mechanical Properties Of Additive Manufacturing Titanium Alloys After Thermal Processing, Ahmet Alptug Tanrikulu

Dissertations and Theses

Titanium alloys are widely used for aerospace and biomaterial applications since their high specific strength, and high corrosion resistivity. Besides these properties, titanium is an excellent biocompatible material widely used for internal body implants. Because the products have complex geometries in both applications, Additive Manufacturing (AM) methods have been recently applied for production. AM methods can process a direct 3-D shape of the final product, decrease total production time and cost. However, high residual stress of the final product limits the application of AM components, especially the ones that are exposed to cyclic loading. In the present study, the initial ...


Structural Behavior Of Lap Shear Connections With Thermally Insulating Filler Plates, Salih Qasim Mahmood Dec 2017

Structural Behavior Of Lap Shear Connections With Thermally Insulating Filler Plates, Salih Qasim Mahmood

Dissertations and Theses

This research consists of experimental load tests and numerical simulations of structural steel connections with various filler materials to study the effect of non-steel fillers on the connection strength. Non-steel fillers are used in the steel connections to provide thermal insulation by reducing thermal bridging. Eight specimens having steel and polypropylene filler plates of various thicknesses were tested in the laboratory. The collected data were compared to a Finite Element Analysis (FEA) using ABAQUS to validate the numerical results. After validation, three parametric studies were conducted using ABAQUS to provide insight into general behavior of connections with a variety of ...


Utilizing High-Resolution Archived Transit Data To Study Before-And-After Travel-Speed And Travel-Time Conditions, Travis Bradley Glick Dec 2017

Utilizing High-Resolution Archived Transit Data To Study Before-And-After Travel-Speed And Travel-Time Conditions, Travis Bradley Glick

Dissertations and Theses

Travel times, operating speeds, and service reliability influence costs and service attractiveness. This paper outlines an approach to quantify how these metrics change after a modification of roadway design or transit routes using archived transit data. The Tri-County Metropolitan Transportation District of Oregon (TriMet), Portland's public transportation provider, archives automatic vehicle location (AVL) data for all buses as part of their bus dispatch system (BDS). This research combines three types of AVL data (stop event, stop disturbance, and high-resolution) to create a detailed account of transit behavior; this probe data gives insights into the behavior of transit as well ...


Technology Planning For Aligning Emerging Business Models And Regulatory Structures: The Case Of Electric Vehicle Charging And The Smart Grid, Kelly R. Cowan Dec 2017

Technology Planning For Aligning Emerging Business Models And Regulatory Structures: The Case Of Electric Vehicle Charging And The Smart Grid, Kelly R. Cowan

Dissertations and Theses

Smart grid has been described as the Energy Internet: Where Energy Technology meets Information Technology. The incorporation of such technology into vast existing utility infrastructures offers many advantages, including possibilities for new smart appliances, energy management systems, better integration of renewable energy, value added services, and new business models, both for supply- and demand-side management. Smart grid also replaces aging utility technologies that are becoming increasingly unreliable, as the average ages for many critical components in utility systems now exceed their original design lives. However, while smart grid offers the promise of revolutionizing utility delivery systems, many questions remain about ...


Physics Based Approach For Seafloor Classification, Phu Duy Nguyen Dec 2017

Physics Based Approach For Seafloor Classification, Phu Duy Nguyen

Dissertations and Theses

The seafloor properties are of high importance for many applications such as marine biology, oil and gas exploration, laying cables, dredging operations and off-shore construction. Several approaches exist to classify the properties of the seabed. These include taking direct samples of the seabed (e.g., coring), however, these methods are costly and slow. Underwater acoustic remote sensing techniques are of interest because they are lower cost and faster. The information about the seabed properties can be extracted by studying the energy of single beam echo sounders (SBES). This can be done by either phenomenological or numerical methods [1], [2]. This ...


Multi-Dimensional Drought Risk Assessment Based On Socio-Economic Vulnerabilities And Hydro-Climatological Factors, Ali Ahmadalipour Nov 2017

Multi-Dimensional Drought Risk Assessment Based On Socio-Economic Vulnerabilities And Hydro-Climatological Factors, Ali Ahmadalipour

Dissertations and Theses

Drought is among the costliest natural hazards developing slowly and affecting large areas, which imposes severe consequences on society and economy. Anthropogenic climate change is expected to exacerbate drought in various regions of the globe, making its associated socioeconomic impacts more severe. Such impacts are of higher concern in Africa, which is mainly characterized by arid climate and lacking infrastructure as well as social development. Furthermore, the continent is expected to experience vast population growth, which will make it more vulnerable to the adverse effects of drought. This study provides the first comprehensive multi-dimensional assessment of drought risk across the ...


Analysis Of The Acid-Base Balance Of Mainstream Tobacco Smoke And Its Effect On The Gas/Particle Partitioning Of Nicotine, Amy Kathleen Devita-Mcbride Nov 2017

Analysis Of The Acid-Base Balance Of Mainstream Tobacco Smoke And Its Effect On The Gas/Particle Partitioning Of Nicotine, Amy Kathleen Devita-Mcbride

Dissertations and Theses

Tobacco smoke particulate matter (PM) is a complex mixture of condensed organic compounds, with about 5 to 10% water. Its general properties are similar in some respects to that of atmospheric organic aerosol PM and thus provides a useful surrogate when studying atmospheric PM. Due to its ability to undergo acid-base chemistry, nicotine is of particular interest in the tobacco smoke system. The gas/particle partitioning of nicotine depends on the protonation state of nicotine in the particles, so the distribution of nicotine between these phases provides a means of understanding the acid-base balance in the tobacco smoke system. The ...


Elution Tailing Of Nonaqueous Phase Liquids In Porous Media, Louisa Orr Nov 2017

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 yeild 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 ...


Evaluating The Performance Of Contech’S Stormfilter With Zpg Media Under The City Of Portland’S 2016 Stormwater Management Manual Requirements For Manufactured Stormwater Treatment Technologies, Mawj T.H. Khammas Nov 2017

Evaluating The Performance Of Contech’S Stormfilter With Zpg Media Under The City Of Portland’S 2016 Stormwater Management Manual Requirements For Manufactured Stormwater Treatment Technologies, Mawj T.H. Khammas

Civil and Environmental Engineering Master's Project Reports

Stormwater runoff is the water generated from excess rainfall or snowmelt that flows over impervious surfaces such as paved roads, parking lots, and on roofs, it often carries a variety of pollutants that adversely affect water quality in that region. Portland is a well-developed city; the majority of the streets are paved and impervious and will consequently generate a tremendous amount of stormwater this creates the necessity for management to help preserve and mimic natural hydrologic cycle through improving water quality. The StormFilter® with ZPG media, manufactured by CONTECH, is a manufactured stormwater treatment technology(MSTT) in which zeolite, perlite ...


Torrefaction Kinetics Of Hemp Hurds, An Emerging Agricultural Byproduct, In A Small Retort, Tel Jensen Sep 2017

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 ...


Making Software, Making Regions: Labor Market Dualization, Segmentation, And Feminization In Austin, Portland And Seattle, Dillon Mahmoudi Sep 2017

Making Software, Making Regions: Labor Market Dualization, Segmentation, And Feminization In Austin, Portland And Seattle, Dillon Mahmoudi

Dissertations and Theses

Through mixed-methods research, this dissertation details the regionally variegated and place-specific software production processes in three second-tier US software regions. I focus on the relationship between different industrial, firm, and worker production configurations and broad-based economic development, prosperity, and inequality. I develop four main empirical findings.

First, I argue for a periodization of software production that tracks with changes in software laboring activity, software technologies, and wage-employment relationships. Through a GIS-based method, I use the IPUMS-USA to extensively measure the amount and type of software labor in industries across the US between 1970 and 2015. I map the uneven geography ...


The Social Acceptance Of Community Solar: A Portland Case Study, Anne Weaver Sep 2017

The Social Acceptance Of Community Solar: A Portland Case Study, Anne Weaver

Dissertations and Theses

Community solar is a renewable energy practice that's been adopted by multiple U.S. states and is being considered by many more, including the state of Oregon. A recent senate bill in Oregon, called the "Clean Electricity and Coal Transition Plan", includes a provision that directs the Oregon Public Utility Commission to establish a community solar program for investor-owned utilities by late 2017. Thus, energy consumers in Portland will be offered participation in community solar projects in the near future. Community solar is a mechanism that allows ratepayers to experience both the costs and benefits of solar energy while ...


A Statistical Investigation Of Lower Columbia River Water Temperature, 1915-2003, Corina Christina Mae Overman Aug 2017

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 separated into an historical period (1938-1956 ...


Ozone Interaction With Indoor Building Materials And Hvac Filters, Omed Akber Abbass Aug 2017

Ozone Interaction With Indoor Building Materials And Hvac Filters, Omed Akber Abbass

Dissertations and Theses

As modern life develops, humans spend most of their time inside buildings. Understanding the effects of different building materials that exist indoors on indoor air quality is crucial to ensure comfort, health, and productivity of building occupants. Indoor air quality (IAQ) is an important field of building science that focuses on studying the existence of different compounds indoors. These compounds include: airborne particles such as dust, volatile organic compounds (VOCs) such as carbonyls, reactive gases such as radon, ozone and others. Ozone is a strong oxidant gas that has adverse effects on human health, and is highly reactive with building ...


Reduced Order Description Of Experimental Two-Phase Pipe Flows: Characterization Of Flow Structures And Dynamics Via Proper Orthogonal Decomposition, Bianca Fontanin Viggiano Aug 2017

Reduced Order Description Of Experimental Two-Phase Pipe Flows: Characterization Of Flow Structures And Dynamics Via Proper Orthogonal Decomposition, Bianca Fontanin Viggiano

Dissertations and Theses

Multiphase pipe flow is investigated using proper orthogonal decomposition for tomographic X-ray data, where holdup, cross-sectional phase distributions and phase interface characteristics within the pipe are obtained. Six cases of stratified and mixed flow with water content of 10%, 30% and 80% are investigated to gain insight into effects of velocity and proportion of water on the flow fields. Dispersed and slug flows are separately analyzed to consider the added interface complexity of the flow fields. These regimes are also highly applicable to industry operational flows. Instantaneous and fluctuating phase fractions of the four flow regime are analyzed and reduced ...


Issues In Urban Trip Generation, Kristina Marie Currans Aug 2017

Issues In Urban Trip Generation, Kristina Marie Currans

Dissertations and Theses

In the 1976, the Institute of Transportation Engineers (ITE) compiled their first Handbook of guidelines and methods for evaluating development-level transportation impacts, specifically vehicular impacts (Institute of Transportation Engineers 1976). Decades later, these methods--essentially the same as when they were originally conceived--are used ubiquitously across the US and Canada. Only recently, with the guidelines in its third edition of the ITE's Trip Generation Handbook (Institute of Transportation Engineers 2014) new data and approaches have been adopted--despite substantial evidence that questions the accuracy of older data, automobile bias, and lack of sensitivity to urban contexts.

This dissertation contributes to this ...


Laser As A Tool To Study Radiation Effects In Cmos, Bahar Ajdari Aug 2017

Laser As A Tool To Study Radiation Effects In Cmos, Bahar Ajdari

Dissertations and Theses

Energetic particles from cosmic ray or terrestrial sources can strike sensitive areas of CMOS devices and cause soft errors. Understanding the effects of such interactions is crucial as the device technology advances, and chip reliability has become more important than ever. Particle accelerator testing has been the standard method to characterize the sensitivity of chips to single event upsets (SEUs). However, because of their costs and availability limitations, other techniques have been explored. Pulsed laser has been a successful tool for characterization of SEU behavior, but to this day, laser has not been recognized as a comparable method to beam ...


Lithography Hotspot Detection, Jea Woo Park Jul 2017

Lithography Hotspot Detection, Jea Woo Park

Dissertations and Theses

The lithography process for chip manufacturing has been playing a critical role in keeping Moor's law alive. Even though the wavelength used for the process is bigger than actual device feature size, which makes it difficult to transfer layout patterns from the mask to wafer, lithographers have developed a various technique such as Resolution Enhancement Techniques (RETs), Multi-patterning, and Optical Proximity Correction (OPC) to overcome the sub-wavelength lithography gap.

However, as feature size in chip design scales down further to a point where manufacturing constraints must be applied to early design phase before generating physical design layout. Design for ...


Synthesis Of Linear Reversible Circuits And Exor-And-Based Circuits For Incompletely Specified Multi-Output Functions, Ben Schaeffer Jul 2017

Synthesis Of Linear Reversible Circuits And Exor-And-Based Circuits For Incompletely Specified Multi-Output Functions, Ben Schaeffer

Dissertations and Theses

At this time the synthesis of reversible circuits for quantum computing is an active area of research. In the most restrictive quantum computing models there are no ancilla lines and the quantum cost, or latency, of performing a reversible form of the AND gate, or Toffoli gate, increases exponentially with the number of input variables. In contrast, the quantum cost of performing any combination of reversible EXOR gates, or CNOT gates, on n input variables requires at most O(n2/log2n) gates. It was under these conditions that EXOR-AND-EXOR, or EPOE, synthesis was developed.

In this work ...


Design And Experimental Investigation Of 500kv Current Transformer Seismic Retrofit Utilizing Structure Rocking And Supplemental Damping With Self-Centering, Ilya S. Palnikov Jul 2017

Design And Experimental Investigation Of 500kv Current Transformer Seismic Retrofit Utilizing Structure Rocking And Supplemental Damping With Self-Centering, Ilya S. Palnikov

Dissertations and Theses

Electrical substations perform a key role in electrical transmission and distribution; the ability for a substation to remain functional during and after a seismic event contributes significantly to the resilience of the clients supplied. Many legacy components currently installed in the main grid substations were designed with minimal consideration of lateral loads and are not qualified per IEEE693. One of the more critical high-voltage substation components that are vulnerable to earthquake damage is the 500kV freestanding current transformer (CT). The CT is particularly vulnerable due to the slenderness and mass distribution of the component. Current transformers are typically constructed from ...


Impact Analysis Of Increased Dispatchable Resources On A Utility Feeder In Opendss, Crystal Eppinger Jul 2017

Impact Analysis Of Increased Dispatchable Resources On A Utility Feeder In Opendss, Crystal Eppinger

Dissertations and Theses

Oregon utilities are replacing their portfolios of traditional fossil fuel generation with renewable generating sources. Stepping away from carbon-producing energy will leave a deficit of on-demand power, resulting in decreased reliability. To overcome these technical challenges, utilities must maximize the use of their present dispatchable resources. One such resource is the Portland General Electric (PGE) Dispatchable Standby Generation Program (DSG), which is an aggregated 105 MWs of distributed generation (DG). These resources are brought on-line when there is a critical need for power. Resources are added to the program if a transfer trip scheme is in place or a modeling ...


Trace Metals In Stormwater: Alternative Best Management Practices, Jennifer Ibeth Mora Jun 2017

Trace Metals In Stormwater: Alternative Best Management Practices, Jennifer Ibeth Mora

Civil and Environmental Engineering Master's Project Reports

Heavy metals, such as copper (Cu) and zinc (Zn), are considered hazardous in natural waters due to their toxicity and non-biodegradability. The focus of this study is to use batch experiments to investigate the heavy metal (Cu and Zn) removal efficiency of perlite and EarthliteTM to improve in-situ filtration systems for stormwater catchment basins. Stormwater samples from two field sites in Portland, OR, chosen to represent a high-use commercial site and high-traffic urban road, were characterized to inform experimental design and compare to values found in literature. The Linear, Freundlich, and Langmuir isotherm models were used to describe equilibrium ...


Early Layout Design Exploration In Tsv-Based 3d Integrated Circuits, Mohammad Abrar Ahmed Jun 2017

Early Layout Design Exploration In Tsv-Based 3d Integrated Circuits, Mohammad Abrar Ahmed

Dissertations and Theses

Through silicon via (TSV) based 3D integrated circuits have inspired a novel design paradigm which explores the vertical dimension, in order to alleviate the performance and power limitations associated with long interconnects in 2D circuits. TSVs enable vertical interconnects across stacked and thinned dies in 3D-IC designs, resulting in reduced wirelength, footprint, faster speed, improved bandwidth, and lesser routing congestion. However, the usage of TSVs itself gives rise to many critical design challenges towards the minimization of chip delay and power consumption. Therefore, realization of the benefits of 3D ICs necessitates an early and realistic prediction of circuit performance during ...


Generalized Differential Calculus And Applications To Optimization, R. Blake Rector Jun 2017

Generalized Differential Calculus And Applications To Optimization, R. Blake Rector

Dissertations and Theses

This thesis contains contributions in three areas: the theory of generalized calculus, numerical algorithms for operations research, and applications of optimization to problems in modern electric power systems. A geometric approach is used to advance the theory and tools used for studying generalized notions of derivatives for nonsmooth functions. These advances specifically pertain to methods for calculating subdifferentials and to expanding our understanding of a certain notion of derivative of set-valued maps, called the coderivative, in infinite dimensions. A strong understanding of the subdifferential is essential for numerical optimization algorithms, which are developed and applied to nonsmooth problems in operations ...


Utilization Of Remote Sensing In Drought Monitoring Over Iraq, Yousif Almamalachy May 2017

Utilization Of Remote Sensing In Drought Monitoring Over Iraq, Yousif Almamalachy

Dissertations and Theses

Agricultural drought is a creeping disaster that overshadows the vegetative cover in general and cropland specifically in Iraq, a country that was well known for its agricultural production and fertile soil. In the recent years, the arable lands in Iraq experienced increasing land degradation that led to desertification, economic losses, food insecurity, and deteriorating environment. Remote sensing is employed in this study and four different indices are utilized, each of which is derived from MODIS satellite mission products. Agricultural drought maps are produced from 2003 to 2015 after masking the vegetation cover. Year 2008 was found the most severe drought ...


Investigation Into Effects Of Instability And Reactivity Of Hydride-Passivated Silicon Nanoparticles On Interband Photoluminescence, Christine Marie Radlinger May 2017

Investigation Into Effects Of Instability And Reactivity Of Hydride-Passivated Silicon Nanoparticles On Interband Photoluminescence, Christine Marie Radlinger

Dissertations and Theses

While silicon has long been utilized for its electronic properties, its use as an optical material has largely been limited due to the poor efficiency of interband transitions. However, discovery of visible photoluminescence (PL) from nanocrystalline silicon in 1990 triggered many ensuing research efforts to optimize PL from nanocrystalline silicon for optical applications. Currently, use of photoluminescent silicon nanoparticles (Si NPs) is commercially limited by: 1) the instability of the energy and intensity of the PL, and 2) the low quantum yield of interband PL from Si NPs.

Herein, red-emitting, hydrogen-passivated silicon nanoparticles (H-Si NPs) were synthesized by thermally-induced disproportionation ...


An Ir And Rf Based System For Functional Gait Analysis In A Multi-Resident Smart-Home, Erich Reinhardt Schafermeyer Apr 2017

An Ir And Rf Based System For Functional Gait Analysis In A Multi-Resident Smart-Home, Erich Reinhardt Schafermeyer

Dissertations and Theses

Changes in the gait characteristics, such as walking speed and stride length, of a person living at home can be used to presage cognitive decline, predict fall potential, monitor long-term changes in cognitive impairment, test drug regimens, and more. This thesis presents a novel approach to gait analysis in a smart-home environment by leveraging new advances in inexpensive sensors and embedded systems to create novel solutions for in-home gait analysis. Using a simple, non-invasive hardware system consisting entirely of wall-mounted infrared and radio frequency sensor arrays, data is collected on the gait of subjects as they pass by. This data ...


Technology Assessment Model Of Developing Geothermal Energy Resources For Supporting Electrical System: The Case For Oregon, Ahmed Shehab Alshareef Apr 2017

Technology Assessment Model Of Developing Geothermal Energy Resources For Supporting Electrical System: The Case For Oregon, Ahmed Shehab Alshareef

Dissertations and Theses

The demand for energy is increasing worldwide. All applications contributed to increase the demand of all energy industry, and therefore the effect on the environment and the rise in pollution increased significantly. This is considered a large problem, and researchers focused their research on renewable energy for reducing the cost of energy in the future. Geothermal energy has significant impact as a source of electricity generation since it will not harm the environment. There are more than twenty countries that benefit from geothermal plants, which generate more than 6000 megawatts .Three alternatives of geothermal energy technology (GHP, Direct use of ...


Microwave Instrumentation And Sensing Techniques For Quantum Efficiency And Minority-Carrier Lifetime Measurements, Kyle Benjamin Lu Mar 2017

Microwave Instrumentation And Sensing Techniques For Quantum Efficiency And Minority-Carrier Lifetime Measurements, Kyle Benjamin Lu

Dissertations and Theses

A non-contact method characterizing the quantum efficiency of a solar cell using the microwave reflectance signature is presented in this thesis. Traditional solar cell quantum efficiency (QE) measurements are only possible near the completion of the fabrication process using contacts in direct physical connection with the metalized surface tabs to probe and extract charge carriers from the device. However, pressure within the solar metrology industry to report the spectral performance of the device earlier in the manufacturing process as part of the process control loop requires that a new non-contact method be developed. This thesis work contributes the development of ...


Building Energy Model Calibration For Retrofit Decision Making, Nicolas R. Johnson Mar 2017

Building Energy Model Calibration For Retrofit Decision Making, Nicolas R. Johnson

Dissertations and Theses

Accommodating the continued increase in energy demand in the face of global climate change has been a worldwide concern. With buildings in the US consuming nearly 40% of national energy, a concerted effort must be given to reduce building energy consumption. As new buildings continue to improve their efficiency through more restrictive energy codes, the other 76.9 billion square feet of current building stock falls further behind. The rate at which current buildings are being retrofit is not enough and better tools are needed to access the benefits of retrofits and the uncertainties associated with them. This study proposes ...