Engineering Commons^™

Quantification Of Reynolds Shear Stress Wave-Phase Dependence In Fixed-Bottom Offshore Wind Turbine Via Quadrant Analysis, Cerrina Mouchref

University Honors Theses

As the need for a reliable renewable energy supply is increasing, many have looked to offshore wind because they hold more potential for power production than onshore wind. Interests in expanding offshore wind energy has brought along many challenges when it comes to understanding the complex dynamics experienced offshore, including the relationship between the wind-turbine generated wakes and ocean waves. This experimental study characterizes the relationship between Reynolds shear stress and the phase of surface waves above the air-sea interface in the wind-turbine wake region. The experimental setup combines a wave tank, wind tunnel, and a fixed-bottom wind turbine. Particle …

Seismic Performance Design Criteria Of Existing Bridge Bent Plastic Hinge Region And Rapid Repair Measures Of Earthquake Damaged Bridges Considering Future Resilience, A K M Golam Murtuz

Dissertations and Theses

The main objective of this research was to evaluate the seismic performance of existing sub-standard reinforced concrete (RC) bridge column-spread footing subassemblies and to quantify the material strain limits through a full-scale experimental program. A total of six column-footing test specimens with pre-1990 construction details were subjected to reverse cyclic lateral loading, utilizing a conventional three-cycle symmetric loading protocol and a protocol representing the demands expected from a CSZ earthquake. Additionally, the tests were designed so that variable axial loading could be applied to simulate the secondary load effects experienced during an earthquake in a column that is part of …

Robust Design Methodologies Under Performance Variations For More Than Moore Technologies: Cnfets & 3dics, Satya Keerthi Vendra

Dissertations and Theses

Various emerging technologies have shown great potential of supplementing silicon transistors as Moore's law slows down. One such disruptive technology, Carbon Nanotube Field Effect Transistors (CNFET), among others, promises increased speed and integration with reduced power consumption. However, due to a limited controllability over the Carbon Nano-tube(CNT) growth process, CNFETs show large variations in their performance and behavior. It is therefore difficult to predict and model their behavior while design suggestions are also challenging. CNT variations are important for a realistic delay modelling. Due to the presence of CNT-specific variations, conventional CMOS evaluation techniques cannot be used for CNFETs.

This …

Effects Of Long Duration Earthquakes On The Interaction Of Inertial And Liquefaction-Induced Kinematic Demands On Pile-Supported Wharves, Milad Souri, Arash Khosravifar, Stephen E. Dickenson, Nason Mccullough, Scott Schlechter

Civil and Environmental Engineering Faculty Publications and Presentations

Nonlinear dynamic analyses were performed to evaluate the effects of ground motion duration on the dynamic response of a pile-supported wharf subjected to liquefaction-induced lateral ground deformations. The numerical model was first calibrated using recorded data from a well-instrumented centrifuge test, after which incremental dynamic analyses were conducted using a suite of spectrally matched motions with different durations. The nonlinear dynamic analyses were performed to evaluated three loading scenarios: combined effects of inertial loads from the wharf deck and kinematic loads from ground deformations, deck inertial loads only in the absence of liquefaction (with minimal kinematic loads), and kinematic loads …

Efficient Capture Of Co2 And Its Selective Reduction To Formic Acid Using Tin-Based Nanomaterials, Emmanuel Oluwaseun Abdul

Dissertations and Theses

CO₂ emissions from the combustion of fossil fuels and other anthropogenic sources have become the main contributing factors to global warming. Chemical methods of absorbing/capturing CO₂ from combustion flue gases have made it a sought-after approach in engineering emission solutions because of its simplistic and convenient operation and high absorption efficiency. The conversion of CO₂ into renewable fuels and high energy density chemicals by clean and economic processes has drawn scientists' attention over the decades. The electrocatalytic conversion of CO₂ using Sn-based materials has been demonstrated to be a promising method for producing formate, an important …

Per-Person And Whole-Building Voc Emission Factors In An Occupied School With Gas-Phase Air Cleaning., Brett W. Stinson, Aurélie Laguerre, Elliott T. Gall

Mechanical and Materials Engineering Faculty Publications and Presentations

Using real-time measurements of CO and volatile organic compounds (VOCs) in the air handler of an occupied middle school, we quantified source strengths for 249 VOCs and apportioned the source to the building, occupants and their activities, outdoor air, or recirculation air. For VOCs quantified in this study, there is a source to the outdoors of 8.6 ± 1.8 g/h in building exhaust air, of which 5.9 ± 1.7 g/h can be attributed to indoor sources (the building and occupants and their activities). The corresponding whole-building area emission factor from indoor sources is 1020 ± 300 μg/(m h), including reactive …

A Self-Referencing Non-Destructive Test Method To Detect Damage In Reinforced Concrete Bridge Decks Using Nonlinear Vibration Response Characteristics, Ali Hafiz, Thomas Schumacher, Anis M. Raad

Civil and Environmental Engineering Faculty Publications and Presentations

Several non-destructive test (NDT) methods, namely visual inspection, hammer sounding, chain drag, impulse response testing, impact echo testing, ultrasonic (array) echo testing, and under certain conditions ground penetrating radar (GPR) are currently used to detect and estimate the extent of damage such as delaminations in reinforced concrete bridge decks. In this article, we present a self-referencing NDT method that builds on impulse response (IR) testing to detect damage using nonlinear vibration characteristics. The hypothesis is that for an undamaged deck, varying the impact force applied to a specific test point does not affect the corresponding frequency response function (FRF) for …

Novel Fabrication Of Silver-Coated Copper Nanowires With Organic Compound Solution, Suhyun Lee, Chien Wern, Sung Yi

Mechanical and Materials Engineering Faculty Publications and Presentations

Copper nanowires and Cu-Ag nanowires have various potential applications, such as transparent conductive film, flexible electronics, and conductive filler. In this study, we developed a new green fabrication method for silver-coated copper nanowires using methylsulfonylmethane (DMSO2), which is an environmentally friendly chemical at the food-grade level, to replace toxic chemicals, including ammonia, in the silver coating process. Copper nanowires were synthesized under various reaction temperatures and concentrations of hydrazine (N2H4), ethylenediamine (EDA), sodium hydroxide (NaOH), and copper precursor. The reaction temperature higher than 70 C caused the oxidation of copper products and evaporation of the sample solution. The optimal conditions …

A Synergic Quantum Particle Swarm Optimisation For Constrained Combinatorial Test Generation, Xu Guo, Xiaoyu Song, Jian-Tao Zhou

Electrical and Computer Engineering Faculty Publications and Presentations

Combinatorial testing (CT) can efficiently detect failures caused by interactions of parameters of software under test. The CT study has undergone a transition from traditional CT to constrained CT, which is crucial for real-world systems testing. Under this scenario, constrained covering array generation (CCAG), a vital combinatorial optimisation issue targeted with constructing a test suite of minimal size while properly addressing constraints, remains challenging in CT. To the authors’ best knowledge, this paper presents a synergic method first based on quantum particle swarm optimisation (QPSO) for the CCAG problems. Three auxiliary strategies, including contraction-expansion coefficient adaptive change strategy, differential evolution …

Inertial Sensor Algorithm To Estimate Walk Distance, Vrutangkumar Shah, Carolin Curtze, Kristen Sowalsky, Ishu Arpan, Martina Mancini, James Mcnames, Mahmoud El-Gohary, Fay Horak, Patricia Carlson-Kuhta

Electrical and Computer Engineering Faculty Publications and Presentations

The “total distance walked” obtained during a standardized walking test is an integral component of physical fitness and health status tracking in a range of consumer and clinical applications. Wearable inertial sensors offer the advantages of providing accurate, objective, and reliable measures of gait while streamlining walk test administration. The aim of this study was to develop an inertial sensor-based algorithm to estimate the total distance walked using older subjects with impaired fasting glucose (Study I), and to test the generalizability of the proposed algorithm in patients with Multiple Sclerosis (Study II). All subjects wore two inertial sensors (Opals by …

The Impact Of New Light Rail Service On Employment Growth In Portland, Oregon, Lahar Santra

Dissertations and Theses

This study quantitatively examines the impact of the new Light Rail Transit (LRT) service on employment growth in retail, knowledge, and service sectors before and after opening the LRT. At the corridor level, this study conducts a case study of Greenline in Southeast Portland, Oregon. The results of the corridor level study suggest that the new LRT service increased employment along the Greenline corridor among all the three sectors of interest- retail, knowledge, service in the long-term (ten years) while having slightly different results for the short-term (five years), likely due to the slow growth of LRT benefits. This study …

Analyzing Modeled Torque Profiles To Understand Scale-Dependent Active Muscle Responses In The Hip Joint, Fletcher Young, Hillel J. Chiel, Matthew Tresch, Charles Heckman, Alexander J. Hunt, Roger Quinn

Mechanical and Materials Engineering Faculty Publications and Presentations

Animal locomotion is influenced by a combination of constituent joint torques (e.g., due to limb inertia and passive viscoelasticity), which determine the necessary muscular response to move the limb. Across animal size-scales, the relative contributions of these constituent joint torques affect the muscular response in different ways. We used a multi-muscle biomechanical model to analyze how passive torque components change due to an animal’s size-scale during locomotion. By changing the size-scale of the model, we characterized emergent muscular responses at the hip as a result of the changing constituent torque profile. Specifically, we found that activation phases between extensor and …

Materials And Methodologies For Spectroscopic And Optical Analytical Applications In Cultural Heritage Conservation Science, Lyndsay Nichole Kissell

Dissertations and Theses

The field of conservation science falls in the intersection of science and art. The work of conservation scientists may include any single subdiscipline of chemistry, though it is most commonly a highly interdisciplinary field taking skills from analytical, organic, and inorganic chemistry, as well as surface and materials science. The aims of conservation scientists are to answer questions about the production and aging of material cultural heritage. Knowing the materials used by an artist can lead to insight about the intentions of the object and knowing how those materials degrade will enable the use of preventative measures to ensure the …

Random Lasing In Nano-Crystalline Zinc-Oxide Films, Benito Reynaldo Resendiz

Dissertations and Theses

In this thesis, we explore the preparation of random lasers (RLs) using solution-deposited, randomly packed nano-particle films of zinc oxide (ZnO) impregnated with silicon dioxide (SiO₂) nanospheres. RLs have their scatterers randomly oriented, while their lasing comes from light propagating along closed paths through the scattering environment. It is shown here that random lasing is readily observed in films made of submicron sized ZnO particles. Adding transparent SiO₂ nanospheres to the films, we show there is an effective improvement of the lasing that is observable in all of the samples spectra. Specifically, we found that the lasing …

Development Of A Testing Station For Grid-Interactive Smart Inverter Systems, Yudong Lan

Dissertations and Theses

As renewable energy penetration increases within the electrical power grid, flexible power is required to ensure reliability. Reliability can be jeopardized by the fluctuation and non-dispatch ability of renewable generators. This instability is caused by an imbalance between the amount of power produced and the amount of power consumed. Grid-enabled battery inverter systems are considered a solution to offset voltage and frequency fluctuations, which arise due to this power imbalance.

The objective of this work is to develop a system for testing grid-enabled inverters. These inverters use one or more communication standards to control their interactions with the grid. This …

Entrainment, Diffusion And Effective Compressibility In A Self-Similar Turbulent Jet, Thomas Basset, Bianca Viggiano, Thomas Barois, Mathieu Gibert, Nicolas Mordant, Raúl Bayoán Cal, Romain Volk, Mickael Bourgoin

Mechanical and Materials Engineering Faculty Publications and Presentations

An experimental Lagrangian study based on particle tracking velocimetry has been completed in an incompressible turbulent round water jet freely spreading into water. The jet is seeded with tracers only through the nozzle: inhomogeneous seeding called nozzle seeding. The Lagrangian flow tagged by these tracers therefore does not contain any contribution from particles entrained into the jet from the quiescent surrounding fluid. The mean velocity field of the nozzle seeded flow, ⟨Uφ⟩, is found to be essentially indistinguishable from the global mean velocity field of the jet, ⟨U⟩, for the axial velocity while significant deviations are found for the radial …

Hamilton’S Geoacoustic Model, Charles W. Holland, Stan E. Dosso

Electrical and Computer Engineering Faculty Publications and Presentations

Hamilton’s classic 1980 paper² formulated the modern concept of a seabed geoacoustic model, drawing on extensive literature to com- pile and synthesize information on seabed properties. Hamilton defined a geoacoustic model as a “model of the real seafloor with emphasis on measured, extrapolated, and predicted values of those properties important in underwater acoustics” that includes “the true thicknesses and properties of sediment and rock layers.” His work provided both the framework for predicting geoacoustic properties and the data to support it.

Hamilton complied geoacoustic information from diverse sources, including laboratory measurements, in situ probes, samples and cores, echo-sounder records, …

Evaluation Of Posted Speed Limits Reductions On Urban Roads With A High Percentage Of Cyclists, Jaclyn S. Schaefer, Miguel Figliozzi, Avinash Unnikrishnan

Civil and Environmental Engineering Faculty Publications and Presentations

This paper presents a before and after analysis of the impact of posted speed limit (PSL) changes on passenger car (FHWA class two vehicles) speeds in Portland, OR. The study focuses on urban roads, comparing sites that underwent a PSL 5-mph reduction (treatment sites) and sites where the PSL did not change (control sites). Sites with a high percentage of and priority for cyclists (neighborhood greenways) and sites with a more standard traffic composition were compared. Differences in speed characteristics such as mean and 85th percentile speeds, the speed variance, and the proportion of vehicles exceeding a speed threshold (relative …

Maximum Profit Facility Location And Dynamic Resource Allocation For Instant Delivery Logistics, Darshan Chauhan, Avinash Unnikrishnan, Stephen D. Boyles

Civil and Environmental Engineering Faculty Publications and Presentations

Increasing e-commerce activity, competition for shorter delivery times, and innovations in transportation technologies have pushed the industry toward instant delivery logistics. This paper studies a facility location and online demand allocation problem applicable to a logistics company expanding to offer instant delivery service using unmanned aerial vehicles or drones. The problem is decomposed into two stages. During the planning stage, the facilities are located, and product and battery capacity are allocated. During the operational stage, customers place orders dynamically and real-time demand allocation decisions are made. The paper explores a multi-armed bandit framework for maximizing the cumulative reward realized by …

Compound Flooding In Convergent Estuaries: Insights From An Analytical Model, Ramin Familkhalili, Stefan A. Talke, David A. Jay

Civil and Environmental Engineering Faculty Publications and Presentations

We investigate here the effects of geometric properties (channel depth and cross-sectional convergence length), storm surge characteristics, friction, and river flow on the spatial and temporal variability of compound flooding along an idealized, meso-tidal coastal-plain estuary. An analytical model is developed that includes exponentially convergent geometry, tidal forcing, constant river flow, and a representation of storm surge as a combination of two sinusoidal waves. Nonlinear bed friction is treated using Chebyshev polynomials and trigonometric functions, and a multisegment approach is used to increase accuracy. Model results show that river discharge increases the damping of surge amplitudes in an estuary, while …

Additive Manufacturing Design For Affordable Housing Development, Courtney Wright, Lani Nguyen, Jordan Wearing

Engineering and Technology Management Student Projects

Recently, there has been an increasing lack of affordable homes. Since rent, prices, gas, and other utilities continue to rise, wages (especially for low-income individuals) have stayed constant throughout the country. This has caused numerous citizens to not be able to afford a home or even pay rent. This situation has caused a large surge in the homeless community, and it is estimated that approximately 37,500 individuals per day are in need of housing throughout the Pacific Northwest as of January 2020. [1] In response to this issue, our team has provided a goal to provide trendy and affordable homes …

Healthcare Information Security Maturity Model Grande Ronde Hospital, Pallavi Agrawal, Riad Alharithi, Karthik Manjunath, Kamal Thapa, Eric Ingersoll, Sujitha Rajagopal

Engineering and Technology Management Student Projects

Technology offers significant advantages in improving the delivery of healthcare to patients. The technology creates electronic data associated with each patient. The data journey starts from the collection point, through the data warehouses that store the data, the application that processes the data, and the medium that transfers the data throughout the patient's life. Data collection starts with patients filling out web forms on a provider's website. This information is stored for the Healthcare organization in remote servers managed by developers and is shared with healthcare specialists, hospitals, labs, pharmacists, insurance providers, and billing software among many other healthcare workers. …

Reconstructability Analysis: Discrete Multivariate Modeling, Martin Zwick

Complex Systems Faculty Publications and Presentations

An introduction to Reconstructability Analysis for the Discrete Multivariate Modeling course and for other purposes.

A Graph-Based Approach To Boundary Estimation With Mobile Sensors, Sean Onufer Stalley, Dingyu Wang, Gautam Dasarathy, John Lipor

Electrical and Computer Engineering Faculty Publications and Presentations

We consider the problem of adaptive sampling for boundary estimation, where the goal is to identify the two dimensional spatial extent of a phenomenon of interest. Motivated by applications in estimating the spread of wildfires with a mobile sensor, we present a novel graph-based algorithm that is efficient in both the number of samples taken and the distance traveled. The key idea behind our approach is that by sampling locations close to known cut edges (edges whose vertices lie on opposite sides of the boundary), we can reliably find additional cut edges. Our approach repeats this process of using the …

Incentivizing Distributed Energy Resource Participation In Grid Services, Tylor Slay, John M. Acken, Robert B. Bass

Electrical and Computer Engineering Faculty Publications and Presentations

The bulk power system is experiencing a dramatic shift as renewable generation growth continues to accelerate. Large-scale renewables adoption will help societies transition to a low-carbon, low-cost, and environmental-friendly electrical power system. However, the transition from a paradigm of generation following load to one where load follows generation will require large-scale interconnection and coordinated operation of Distributed Energy Resources (DERs), supported by open communication protocols. In this future grid scenario, DER aggregations will provide critical grid services that enable high penetration levels of renewable generation. This position paper presents an Energy Service Interface (ESI) that defines scope for ensuring secure, …

A Field Test Of Direct Load Control Of Water Heaters And Its Implications For Consumers, Midrar Adham, Manasseh Obi, Robert B. Bass

Electrical and Computer Engineering Faculty Publications and Presentations

Utilities and customers are now operating more closely than ever. The prevailing numbers of grid-interactive Distributed Energy Resources are being integrated to provide grid reliability and stability. Different methods of control have been implemented to utilize these Distributed Energy Resources, such as Service-Oriented Load Control and Direct Load Control. This paper investigates the issues associated with the latter. A Direct Load Control method is applied to two Distributed Energy Resources, Electric Water Heater and Heat Pump Water Heater. A load shifting scenario is created where each water heater turns off during water draw events that coincide with peak demand periods. …

A Means For Tuning Primary Frequency Event Detection Algorithms, Sean Keene, Landon Hanks, Robert B. Bass

Electrical and Computer Engineering Faculty Publications and Presentations

Power system balancing authorities are routinely affected by sudden frequency fluctuations. These frequency events can precipitate cascading outages and cause damage to both customer-owned and utility equipment. In this document, we describe an Algorithm Evaluation Environment that uses a suite of metrics to evaluate an algorithm and quantify its efficacy. Using the Algorithm Evaluation Environment, a detection algorithm can be tuned to best match the definition of a frequency event as defined by experts within the context of their own balancing area. We demonstrate the utility of the Algorithm Evaluation Environment using a regression-based frequency event detection algorithm. This algorithm …

The Distributed Trust Model Applied To The Energy Grid Of Things, Narmada Sonali Fernando

Dissertations and Theses

Electric power system operators can manage distribution system utilization and usage by coordinating end customer usage of distributed energy resources. The end customers in this regard are Service Provisioning Customers, who provide their energy resources to a Grid Service Provider, which in turn dispatches large aggregations of distributed energy resources to provide reliable service to the power system. The security of this system relies upon information protection mechanisms, as described in IEEE 2030.5. However, in addition to preventive security measures, a monitoring function is required to ensure trustworthiness.

Trust models are a method to detect and respond to both expected …

The Evaluation Of Performance Of Spindle Connector And Its Finite Element Analysis, Suhyun Lee

Dissertations and Theses

The rapid development of machining technology and reliable high-speed machining systems has led to a fast operation of machines. However, machining machines cannot still meet modern requirements in terms of the quality of parts, the machine components, and the life of the tools. The major components of the machining system are machine tools, the spindle interfaces (the contact between the spindle and the tool holder), and tools. The choice of the spindle connector is the main decision, as this defines the limitation of the metal cutting efficiency and considerably influences the deformation of the machine tool. Therefore, it is very …

A Pipeline For Enhanced Multimodal 2d Imaging Of Concrete Structures, Sina Mehdinia, Thomas Schumacher, Xubo Song, Eric A. Wan

Civil and Environmental Engineering Faculty Publications and Presentations

We present an imaging pipeline to achieve enhanced images of the interior of concrete from ground penetrating radar (GPR) and ultrasonic echo array (UEA) measurements. This work lays the foundation for an advanced yet practical imaging tool to assess concrete structures. Specifically, we propose an enhanced two-dimensional (2D) total focusing method (XTFM) to reconstruct images from raw GPR and UEA data. The proposed XTFM algorithm integrates total focusing method (TFM) and synthetic aperture focusing technique (SAFT) concepts to post-process large independent and interelement measurements from both modalities in a computationally efficient way. Furthermore, we introduce a novel 2D image fusion …