Engineering Commons^™

Floating Wind Farm Experiments Through Scaling For Wake Characterization, Power Extraction, And Turbine Dynamics, Juliaan Bossuyt, OndˇRej FercˇÁk, Zein Sadek, Charles Meneveau, Dennice Gayme, Raúl Bayoán Cal

Mechanical and Materials Engineering Faculty Publications and Presentations

In this study, wind and water tunnel experiments of turbulent wakes in a scaled floating wind farm are performed. Scaling of a floating wind farm with a scaling ratio of 1:400 is made possible by relaxing geometric scaling of the turbine platform system, such that the dynamic response can be correctly matched, and to allow for relaxing Froude scaling such that the Reynolds number can be kept large enough. Four dimensionless parameters, describing the relative importance of wind and wave loads compared to turbine inertia, are used to guide the scaled floater design. Free decay tests of the pitch and …

Sea Level Rise And The Drivers Of Daily Water Levels In The Sacramento-San Joaquin Delta, H. Baranes, Steven Dykstra, D. A. Jay, S. A. Talke

Civil and Environmental Engineering Faculty Publications and Presentations

Water levels in deltas and estuaries vary on multiple timescales due to coastal, hydrologic, meteorologic, geologic, and anthropogenic factors. These diverse factors increase the uncertainty of, and may bias, relative sea level rise (RSLR) estimates. Here, we evaluate RSLR in San Francisco Bay and the Sacramento-San Joaquin Delta, USA by applying a physics-based, nonlinear regression to 50 tide gauges that determines the spatially varying controls on daily mean water level for water years 2004–2022. Results show that elevated river flow and pumping (99th percentile) raise water level up to 6 m and lower it up to 0.35 m, respectively, and …

Quantum Algorithms For Unate And Binate Covering Problems With Application To Finite State Machine Minimization, Abdirahman Alasow, Marek Perkowski

Electrical and Computer Engineering Faculty Publications and Presentations

Covering problems find applications in many areas of computer science and engineering, such that numerous combinatorial problems can be formulated as covering problems. Combinatorial optimization problems are generally NPhard problems that require an extensive search to find the optimal solution. Exploiting the benefits of quantum computing, we present a quantum oracle design for covering problems, taking advantage of Grover’s search algorithm to achieve quadratic speedup. This paper also discusses applications of the quantum counter in unate covering problems and binate covering problems with some important practical applications, such as finding prime implicants of a Boolean function, implication graphs, and minimization …

Chemical Strategies To Mitigate Electrostatic Charging During Coffee Grinding, Joshua Méndez Harper, Christopher H. Hendon

Electrical and Computer Engineering Faculty Publications and Presentations

The process of grinding coffee generates particles with high levels of electrostatic charge, causing a number of detrimental effects including clumping, particle dispersal, and spark discharge. At the brewing level, electrostatic aggregation between particles affects liquid-solid accessibility, leading to variable extraction quality. In this study, we quantify the effectiveness of four charge mitigation strategies. Our data suggests that adding small amounts of water to whole beans pre-grinding, or bombarding the grounds with ions produced from a high-voltage ionizer, are capable of de-electrifying the granular flows. While these techniques helped reduce visible mess, only the static reduction through water inclusion was …

Impact Of Material And Tunnel Barrier Quality On Spin Transport In A Cvd Graphene Non-Local Spin Valve Device Array, Samuel T. Olson, Daniel Still, Kaleb Hood, Otto Zietz, Jun Jiao

Mechanical and Materials Engineering Faculty Publications and Presentations

Wafer-scale graphene films produced via chemical vapor deposition (CVD) are now commercially available, however these films inherently contain randomly distributed defects such as adlayers and grain boundaries. This report discusses the impact of these defects on the signal integrity of an array of graphene-based non-local spin valves (NLSVs). It was found that critical spin parameters fluctuate drastically between adjacent identical devices. Investigation of the channel quality indicated that adlayers do not affect spin signal significantly even when located directly in the spin transport region of the device. In contrast, grain boundary defects within the spin transport region have significant impact …

An Overview Of Elements And Relations: Aspects Of A Scientific Metaphysics, Martin Zwick

Systems Science Faculty Publications and Presentations

A talk on my book, Elements and Relations: Aspects of a Scientific Metaphysics. Book description:

This book develops the core proposition that systems theory is an attempt to construct an “exact and scientific metaphysics,” a system of general ideas central to science that can be expressed mathematically. Collectively, these ideas would constitute a non-reductionist “theory of everything” unlike what is being sought in physics. Inherently transdisciplinary, systems theory offers ideas and methods that are relevant to all of the sciences and also to professional fields such as systems engineering, public policy, business, and social work. To demonstrate the generality …

Multicolor Dye-Based Flow Structure Visualization For Seal-Whisker Geometry Characterized By Computer Vision, Ondřej Ferčák, Kathleen Lyons, Christin T. Murphy, Kristina M. Kamensky, Raul Bayoan Cal

Mechanical and Materials Engineering Faculty Publications and Presentations

Pinniped vibrissae possess a unique and complex three-dimensional topography, which has beneficial fluid flow characteristics such as substantial reductions in drag, lift, and vortex induced vibration. To understand and leverage these effects, the downstream vortex dynamics must be studied. Dye visualization is a traditional qualitative method of capturing these downstream effects, specifically in comparative biological investigations where complex equipment can be prohibitive. High-fidelity numerical simulations or experimental particle image velocimetry (PIV) are commonplace for quantitative high-resolution flow measurements, but are computationally expensive, require costly equipment, and can have limited measurement windows. This study establishes a method for extracting quantitative data …

Quantitative Gait And Balance Outcomes For Ataxia Trials: Consensus Recommendations By The Ataxia Global Initiative Working Group On Digital-Motor Biomarkers, Winfried Ilg, Sarah Milne, Tanja Schmitz-Hübsch, Lisa Alcock, Lukas Beichert, Enrico Bertini, Helen Dawes, Christopher M. Gomez, James Mcnames, Multiple Additional Authors

Electrical and Computer Engineering Faculty Publications and Presentations

With disease-modifying drugs on the horizon for degenerative ataxias, ecologically valid, finely granulated, digital health measures are highly warranted to augment clinical and patient-reported outcome measures. Gait and balance disturbances most often present as the first signs of degenerative cerebellar ataxia and are the most reported disabling features in disease progression. Thus, digital gait and balance measures constitute promising and relevant performance outcomes for clinical trials.

This narrative review with embedded consensus will describe evidence for the sensitivity of digital gait and balance measures for evaluating ataxia severity and progression, propose a consensus protocol for establishing gait and balance metrics …

Shallow‑Water Habitat In The Lower Columbia River Estuary: A Highly Altered System, Will Templeton, David A. Jay, Heida Diefenderfer, Stefan Talke

Civil and Environmental Engineering Faculty Publications and Presentations

Decreases in shallow-water habitat area (SWHA) in the Lower Columbia River and Estuary (LCRE) have adversely affected salmonid populations. We investigate the causes by hindcasting SWHA from 1928 to 2004, system-wide, based on daily higher high water (HHW) and system hypsometry. Physics-based regression models are used to represent HHW along the system as a function of river inflow, tides, and coastal processes, and hypsometry is used to estimate the associated SWHA. Scenario modeling is employed to attribute SWHA losses to levees, flow regulation, diversion, navigational development, and climate-induced hydrologic change, for subsidence scenarios of up to 2 m, and for …

Development Of Prediction Method For Dimensional Stability Of 3d-Printed Objects, Kyung-Eun Min, Jae-Won Jang, Jesik Shin, Cheolhee Kim, Sung Yi

Mechanical and Materials Engineering Faculty Publications and Presentations

Fused deposition modeling (FDM), as one of the additive manufacturing processes, is known for strong layer adhesion suitable for prototypes and end-use items. This study used a multiple regression model and statistical analysis to explore the dimensional accuracy of FDM objects. Factors such as inclination angle, layer thickness, support space, and raster angle were examined. Machine learning models (Gaussian process regression (GPR), support vector machines (SVM), and artificial neural network (ANN)) predicted dimensions using 81 datapoints. The mean squared dimensional error (MSDE) between the measured and designed surface profiles was selected as an output for the dimensional accuracy. Support spacing, …

Accelerating Training Of Mlips Through Small-Cell Training, Jason A. Meziere, Yu Luo, Yi Xia, Laurent Karim Béland, Mark R. Daymond

Mechanical and Materials Engineering Faculty Publications and Presentations

While machine-learned interatomic potentials have become a mainstay for modeling materials, designing training sets that lead to robust potentials is challenging. Automated methods, such as active learning and on-the-fly learning, construct reliable training sets, but these processes can be resource-intensive. Current training approaches often use density functional theory (DFT) calculations that have the same cell size as the simulations that the potential is explicitly trained to model. Here, we demonstrate an easy-to-implement small-cell training protocol and use it to model the Zr-H system. This training leads to a potential that accurately predicts known stable Zr-H phases and reproduces the α-β …

A One-Dimensional Volcanic Plume Model For Predicting Ash Aggregation, D. W. Hoffman, L. G. Mastin, Alexa R. Van Eaton, Stephen Solovitz, Raul Bayoan Cal, J. K. Eaton

Mechanical and Materials Engineering Faculty Publications and Presentations

During explosive volcanic eruptions, volcanic ash is ejected into the atmosphere, impacting aircraft safety and downwind communities. These volcanic clouds tend to be dominated by fine ash (μm in diameter), permitting transport over hundreds to thousands of kilometers. However, field observations show that much of this fine ash aggregates into clusters or pellets with faster settling velocities than individual particles. Models of ash transport and deposition require an understanding of aggregation processes, which depend on factors like moisture content and local particle collision rates. In this study, we develop a Plume Model for Aggregate Prediction, a one-dimensional (1D) volcanic plume …

Localization And Shape Determination Of A Hidden Corridor In The Great Pyramid Of Giza Using Non-Destructive Testing, Mohamed Elkarmoty, Johannes Rupfle, Khalid Helal, Mohamed Sholqamy, Mohamed Fath-Elbab, Jochen Kollofrath, Thomas Schumacher, Multiple Additional Authors

Civil and Environmental Engineering Faculty Publications and Presentations

Built over 4500 years ago, the Great Pyramid of Giza, Egypt, is the only remaining structure of the Wonders of the Ancient World as described by the ancient Greek historian Herodotus. Despite this long existence, only recently has modern science and technology been employed to study this massive stone structure. Cosmic-ray muon radiography throughout the ScanPyramids project has detected a large void above the Grand Gallery of the Great Pyramid and a smaller unidentified void behind the so-called Chevron. The Chevron is an assembly of four large limestone blocks arranged in the shape of two inverted downward open angles. Guided …

Role Of Binder On Yield Strength Of Polycaprolactone/Dimethylsulfone Composites For Bio-Applications, Kyung-Eun Min, Jae-Won Jang, Sung Yi, Cheolhee Kim

Mechanical and Materials Engineering Faculty Publications and Presentations

Polycaprolactone (PCL) and dimethylsulfone (DMSO2) composites can tailor the properties of scaffold materials, allowing their use in bone tissue engineering. With an increase in DMSO2 content, the modulus of the material increases but not the yield strength. In order to increase yield strength, a binder was added. However, the optimization of the content and the mixing process of the binder were not optimized in the previous studies. In this study, gamma-methacryloxypropyltrimethoxysilane (A-174) was used as a binder to increase the strength of a composite. Four different mixing processes were employed based on the binder mixing sequence. The binders with content …

Modeling Yield Strength Of Austenitic Stainless Steel Welds Using Multiple Regression Analysis And Machine Learning, Sukil Park, Myeonghwan Choi, Dongyoon Kim, Cheolhee Kim, Namhyun Kang

Mechanical and Materials Engineering Faculty Publications and Presentations

Designing welding filler metals with low cracking susceptibility and high strength is essential in welding low-temperature base metals, such as austenitic stainless steel, which is widely utilized for various applications. A strength model for weld metals using austenitic stainless steel consumables has not yet been developed. In this study, such a model was successfully developed. Two types of models were developed and analyzed: conventional multiple regression and machinelearning- based models. The input variables for these models were the chemical composition and heat input per unit length. Multiple regression analysis utilized five statistically significant input variables at a significance level of …

Optimally Distributed Receiver Placements Versus An Environmentally Aware Source: New England Shelf Break Acoustics Signals And Noise Experiment, William K. Stevens, Martin Siderius, Matthew J. Carrier, Drew Wendeborn

Electrical and Computer Engineering Faculty Publications and Presentations

This article describes the results of the Spring of 2021 New England Shelf Break Acoustics (NESBA) Signals and Noise experiment as they pertain to the optimization of a field of passive receivers versus an environmentally aware source with end-state goals. A discrete optimization has been designed and used to demonstrate providing an acoustic system operator with actionable guidance relating to optimally distributed receiver locations and depths and likely mean source detection times and associated uncertainties as a function of source and receiver levels of environmental awareness. The uncertainties considered here are those due to the imperfect spatial and temporal sensing …

Low Internal Air Space In Plants With Crassulacean Acid Metabolism May Be An Anatomical Spandrel, Alistair Leverett, Anne Borland, Emma Inge, Samantha Hartzell

Civil and Environmental Engineering Faculty Publications and Presentations

Crassulacean Acid Metabolism (CAM) is a photosynthetic adaptation found in at least 38 plant families. Typically, the anatomy of CAM plants is characterised by large photosynthetic cells and a low percentage of leaf volume comprised of internal air space (% IAS). It has been suggested that reduced mesophyll conductance (g_m) arising from low % IAS benefits CAM plants by preventing the movement of CO₂ out of cells and ultimately minimising leakage of CO₂ from leaves into the atmosphere during day-time decarboxylation. Here, we propose that low % IAS does not provide any adaptive benefit to …

Phase Stability Of Lead Phosphate Apatite, Jiahong Shen, Dale Gaines Ii, S. Shahabfar, Zi Li, Dohun Kang, Sean Griesemer, Adolfo Salgado-Casanova, Tzu-Chen Liu, Yi Xia, Multiple Additional Authors

Mechanical and Materials Engineering Faculty Publications and Presentations

Recently, Cu-substituted lead apatite LK-₉₉ was reported to have room-temperature ambientpressure superconductivity. Here we utilize density functional theory (DFT) total energy and harmonic phonon calculations to investigate the thermodynamic and dynamic stability of two lead phosphate apatites in their pure and Cu-substituted structures. Though Pb₁₀(PO₄)₆O and Pb₁₀(PO₄)₆(OH)₂ are found to be thermodynamically stable (i.e., on the T=₀K ground state convex hull), their Cu-substituted counterparts are above the convex hull. Harmonic phonon calculations reveal dynamic instabilities in all four of these structures. Oxygen vacancy formation …

Modeling And Validating Temporal Rules With Semantic Petri Net For Digital Twins, Han Liu, Xiaoyu Song, Ge Gao, Hehua Zhang, Yu-Shen Liu, Ming Gu

Electrical and Computer Engineering Faculty Publications and Presentations

Semantic rule checking on RDFS/OWL data has been widely used in the construction industry. At present, semantic rule checking is mainly performed on static models. There are still challenges in integrating temporal models and semantic models for combined rule checking. In this paper, Semantic Petri-Net (SPN) is proposed as a novel temporal modeling and validating method, which implements the states and transitions of the Colored Petri-Net directly based on RDFS and SPARQL, and realizes two-way sharing of knowledge between domain semantic webs and temporal models in the runtime. Several cases are provided to demonstrate the possible applications in digital twins …

Assessing The Performance Of Exchange-Correlation Functionals On Lattice Constants Of Binary Solids At Room Temperature Within The Quasiharmonic Approximation, Xiaofei Shao, Peitao Liu, Cesare Franchini, Yi Xia, Jiangang He

Mechanical and Materials Engineering Faculty Publications and Presentations

The exchange-correlation functional is at the core of density functional theory (DFT) and determines the accuracy of DFT in describing the interactions among electrons/ions in solids and molecules. The strongly constrained and appropriately normed functional (SCAN) and its derivatives, regularized SCAN (rSCAN) and regularized-restored SCAN (r2SCAN), are particularly promising due to their remarkable overall accuracy in the description of various properties while retaining a high computational efficiency as compared to hybrid functionals. However, an exhaustive assessment on the performance of these functionals in predicting the finite-temperature lattice constant of solids is still lacking. Here, we systematically study the room-temperature lattice …

Compensation Of Seeding Bias For Particle Tracking Velocimetry In Turbulent Flows, Thomas Barois, Bianca Viggiano, Thomas Basset, Raúl Bayoán Cal, Romain Volk, Mathieu Gibert, Mickael Bourgoin

Mechanical and Materials Engineering Faculty Publications and Presentations

When a fluid in turbulent motion is tagged by a nonuniform concentration of ideal tracers, the mean velocity of the tracers may not match with the mean velocity of the fluid flow. This implies that conventional particle tracking velocimetry will not produce the mean flow of a turbulent flow unless the particle seeding is homogeneous. In this work, we consider the problem of mean flow estimation from a set of particle tracks obtained in a situation of nonhomogeneous seeding. To compensate the bias caused by the nonhomogeneous particle seeding, we propose a modified particle tracking velocimetry method. This method is …

Cu2o Heterojunction Solar Cell With Photovoltaic Properties Enhanced By A Ti Buffer Layer, Binghao Wang, Zhiqiang Chen, Feng Zhao

Center for Electron Microscopy and Nanofabrication Publications and Presentations

In this study, semiconductor oxide cuprite (Cu2O) and indium tin oxide (ITO) heterojunction solar cells with and without a 10 nm thick titanium (Ti) thin film as the buffer layer were fabricated and characterized for comparison. The Cu2O film was formed by low-cost electrodeposition, and Ti and ITO layers were deposited on a glass substrate by sputtering. The interfacial microstructures, surface topology, and electrical and photovoltaic properties of both solar cells were investigated. The test results showed that the Ti buffer layer changed the surface morphology, resistivity, and contact potential of the electrodeposited Cu2O film. With these changes, the photovoltaic …

Lift Force Analysis For An Electrodynamic Wheel Maglev Vehicle, Colton W. Bruce, Jonathan Bird, Matthew K. Grubbs

Electrical and Computer Engineering Faculty Publications and Presentations

This paper used an analytic based 3-D second order vector potential model to study the vertical dynamic force ripple and dynamic airgap height change when using a one pole-pair electrodynamic wheel (EDW) maglev vehicle. A one-pole pair EDW creates the lowest lift specific power; however transient finite element analysis (FEA) also shows that the one pole-pair EDW will create a large oscillating vertical force when maintaining a static airgap height. A dynamically coupled eddy current model was used to confirm that when the airgap length is allowed to change with time then an increase in vertical airgap creates a large …

Modeling Cyanotoxin Production, Fate, And Transport In Surface Water Bodies Using Ce-Qual-W2, Bernadel Rose Hintz Garstecki, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

Cyanobacteria are frequently associated with forming toxic blooms. The toxins produced by cyanobacteria, cyanotoxins, are harmful to both humans and animals. Rising temperatures due to global climate change are expected to increase the occurrence of cyanobacteria, and it is vital that we protect our drinking water supplies and natural water resources. Modeling the production, fate, and transport of these toxins is an important step in limiting exposure to them and evaluating management strategies to mitigate their impact. The research provided here offers an overview of some of the main cyanotoxins of concern and presents preliminary models for the transport and …

Distributed Deep Learning Optimization Of Heat Equation Inverse Problem Solvers, Zhuowei Wang, Le Yang, Haoran Lin, Genping Zhao, Zixuan Liu, Xiaoyu Song

Electrical and Computer Engineering Faculty Publications and Presentations

The inversion problem of partial differential equation plays a crucial role in cyber-physical systems applications. This paper presents a novel deep learning optimization approach to constructing a solver of heat equation inversion. To improve the computational efficiency in large-scale industrial applications, data and model parallelisms are incorporated on a platform of multiple GPUs. The advanced Ring-AllReduce architecture is harnessed to achieve an acceleration ratio of 3.46. Then a new multi-GPUs distributed optimization method GradReduce is proposed based on Ring-AllReduce architecture. This method optimizes the original data communication mechanism based on mechanical time and frequency by introducing the gradient transmission scheme …

Uncovering Transient Dynamics And Equilibrium States Of Particle Aggregates With RaúL BayoáN Cal, RaúL BayoáN Cal

PDXPLORES Podcast

In this episode of PDXPLORES, Raúl Bayoán Cal, Professor of Mechanical & Materials Engineering at the Maseeh College of Engineering and Computer Science, discusses his latest National Science Foundation award-winning research, Uncovering Transient Dynamics and Equilibrium States of Particle Aggregates in Fluids, investigating transient dynamics of fluid mechanics in the absence of gravity. These experiments, which utilize the Dryden Drop Tower and research facilities aboard the International Space Station, will benefit the study of granular media in aggregation models such as pollen deposition, algae growth, and plastic pollution.

Click on the "Download" button to access the audio transcript.

Evaluation Of The Alternatives Of Introducing Electric Vehicles In Developing Countries Using Type-2 Neutrosophic Numbers Based Rafsi Model, Ilgin Gokasar, Muhammet Deveci, Mehtap Isik, Tugrul Daim, Aws A. Zaidan, Florentin Smarandache

Engineering and Technology Management Faculty Publications and Presentations

This study focuses on implementing electric vehicles (EVs) in developing countries where energy production is mainly based on fossil fuels. Although for these countries the environmental short-run benefits of the EVs cannot offset the short-run costs, it may still be the best option to implement the EVs as soon as possible. Hence, it is necessary to evaluate the alternatives to introducing EVs to the market due to the environmental concerns that created an opportunity for some developing countries to catch up with the international competition. Therefore, we develop a case scenario to explore the decision-making process in implementing the EVs …

Evaluation Of Metaverse Traffic Safety Implementations Using Fuzzy Einstein Based Logarithmic Methodology Of Additive Weights And Topsis Method, Muhammet Deveci, Dragan Pamucar, Ilgin Gokasar, Mario Köppen, Brij B. Gupta, Tugrul Daim

Engineering and Technology Management Faculty Publications and Presentations

As the Metaverse’s popularity grows, its effect on everyday problems is beginning to be discussed. The upcoming Metaverse world will influence the transportation system as cross-border lines blur due to rapid globalization. The purpose of this paper is to investigate the capabilities of the Metaverse and its alternatives to traffic safety, as well as to prioritize its advantages. The case study is based on a densely populated metropolis with an extensive education system. The city’s decision-makers will have to weigh the pros and cons of the Metaverse’s effect on traffic safety. To illustrate the complex forces that drive the decision-making …

Spheroidization Heat Treatment Conditions With Data Analysis In Medium Carbon Cr-Mo Steel For Ultra High Strength Cold Heading, Yong Deok Jo, Sung Yi, Byoung Lok Jang

Mechanical and Materials Engineering Faculty Publications and Presentations

The degree to which parameters affect the spheroidization heat treatment of steel was calculated by setting the spheroidization heat treatment conditions of Cr-Mo steel and using data analysis such as S/N ratio and ANOVA. After analyzing the transformation temperatures of the steel, A_c1 and A_c3, using a DSC, the conditions were set accordingly. The surface hardness was measured for the conditions and used as an evaluation index. The correlation was analyzed by comparing the spheroidized volume fraction and the surface hardness, and the Pearson correlation coefficient was -0.88, proving that a correlation existed between the two values. …

The Role Of High-Order Anharmonicity And Off-Diagonal Terms In Thermal Conductivity: A Case Study Of Multi-Phase Cspbbr3, Xiangdong Ding, Guimei Zhu, Yi Xia, Jie Ren, Jun Sun, Multiple Additional Authors

Mechanical and Materials Engineering Faculty Publications and Presentations

We investigate the influence of three- and four-phonon scattering, perturbative anharmonic phonon renormalization, and off-diagonal terms of coherent phonons on the thermal conductivity of CsPbBr3 phase change perovskite, by using advanced implementations and first-principles simulations. Our study spans a wide temperature range covering the entire structural spectrum. Notably, we demonstrate that the interactions between acoustic and optical phonons result in contrasting trends of phonon frequency shifts for the high-lying optical phonons in orthorhombic and cubic CsPbBr3 as temperature varies. Our findings highlight the significance of wavelike tunneling of coherent phonons in ultralow and glasslike thermal conductivity in halide perovskites.