Engineering Commons^™

Capstone Review: Filament Unit Multiplexing Engine, Gal Cohen

University Honors Theses

The Filament Unit Multiplexing Engine (FUME) is a Mechanical Engineering capstone project sponsored by Portland State University's Electronic Prototyping Lab (EPL). The project addresses the need for an automated system to manage 3D printing operations. The current manual process of selecting and routing a spool of filament to one of the available 3D printers is labor-intensive and limits the efficiency of the lab’s 3D printing farm. FUME aims to create a custom solution tailored for a multi-user, multi-spool, and multi-printer environment. The designed system includes key components: a spool holder, an engine, a track and shuttle system, and a funnel. …

Technologies For Wearable Seizure Detection: A Systematic Review, Rhema E. Losli

University Honors Theses

Knowing when a seizure occurred is helpful because this information can be used to evaluate the effectiveness of seizure interventions and possibly alert caregivers to emergency situations. The current practice for recording seizures outside of a hospital and without sensors is through keeping a self-reported seizure diary. This practice may be unreliable if the diary is not updated or the person having the seizure does not realize it is happening. Wearable seizure detectors aim to solve this problem by reliably recording when a seizure happened and either sending out an alert or storing the data for later analysis. In this …

Preservation Of Biomass In Underground Capsules Using An Open-Source Wireless Water Activity Sensor System: Capstone Review, Joshua Varughese

University Honors Theses

This paper highlights the progression of a two-term senior capstone project in the ECE department at Portland State University. Sponsored by Dr. David Burnett from PSU’s WEST Lab, the project aims to produce an affordable wireless monitoring system for water activity. The example scenario focuses on carbon sequestration where wood biomass is buried underground in enclosed capsules. For optimal sequestration, microorganisms capable of decaying the wood and releasing carbon back into the environment must be eliminated. Water activity, a key metric for measuring microbial activity, must be below 0.61 to prevent microbial survival. The system this project was designed for …

Differentiating Dynamic System Outcomes In Cam Photosynthesis Through Sonification, Duncan Turley

Civil and Environmental Engineering Undergraduate Honors Theses

Sonification is a powerful tool that is harnessed by modern engineers to represent information through audio, and is beginning to be used to interpret more complex data sets. Sonification can be used to facilitate the listeners' ability to grasp microscopic or complex changes in the state of a system. This study uses the assigning of sound patterns to model outputs that indicate chaotic or non-chaotic systems in Crassulacean acid metabolism photosynthesis. Using sound allows the interpretation of chaotic data without the more time intensive processes typically used, such as of Fast Fourier Transformations. Based on past research, it is known …

Exploring Cybertechnology Standards Through Bibliometrics: Case Of National Institute Of Standards And Technology, Tugrul Daim, Haydar Yalcin, Alain Mermoud, Valentin Mulder

Engineering and Technology Management Faculty Publications and Presentations

Cyber security is one of the topics that gain importance today. It is necessary to determine the basic components, basic dynamics, and main actors of the Cyber security issue, which is obvious that it will have an impact in many areas from social, social, economic, environmental, and political aspects, as a hot research topic. When the subject literature is examined, it has become a trend-forming research subject followed by institutions and organizations that produce R&D policy, starting from the level of governments. In this study, cybersecurity research is examined in the context of 5 basic cyber security functions specified in …

Enhancing Miter Saw Safety: Challenges And Prospects Of Brake Incorporation With An Automatic Blade Retraction System, Derek S. Cole

University Honors Theses

Miter saws pose significant safety risks with thousands of injuries reported annually. Despite this risk, they are still used every day as they are a necessity for thousands of workers in the United States and globally. This leaves a demand to make these machines safer to mitigate any potential harm. This research addresses the critical need for an automatic safety system for miter saws, aiming to enhance user safety by retracting and stopping the blade upon skin contact. This analysis identified the primary challenge: The large force generated when braking at high speed on a miter saw blade, translates the …

Supercomputers And Quantum Computing On The Axis Of Cyber Security, Haydar Yalcin, Tugrul Daim, Mahdieh Mokhtari Moughari, Alain Mermoud

Engineering and Technology Management Faculty Publications and Presentations

Cybersecurity has become a very critical area to address for governments, industry and the academic community. Cyber attacks are on the rise so is research to address the challenges presented by these attacks. Research yields several technological advancements. This paper explores the development of quantum computing and supercomputers within the context of cybersecurity. As many governments and organizations are under the threat of cyber-attacks, it is critical and timely to explore the status of technological development. We use advanced scientometric techniques to disclose the development status and identify the centers of excellence. The research uses bibliometric data of published papers …

Investigation Of Piezocone Dissipation Test Interpretation In Clay Accounting For Vertical And Horizontal Porewater Pressure Dissipation With A Large Deformation Axisymmetric Penetration Model, Diane Moug, Andrew Huffman, Jason T. Dejong

Civil and Environmental Engineering Faculty Publications and Presentations

The piezocone (CPTu) dissipation test is used to characterize how the applied load from the penetrating cone is distributed between the soil and pore fluid during both penetrometer advancement and when penetration is paused. The coefficient of consolidation is often estimated from CPTu dissipation tests by interpreting the rate of excess porewater pressure (∆u) decay to static conditions during a pause in cone penetration. Most CPTu dissipation test interpretation methods are based on Terzaghi consolidation theory for ∆u dissipation at the cone shoulder (u₂ position) or cone face (u₁ position) and assume that radial ∆u dissipation dominates the …

Rheological Properties And 3d Printing Behavior Of Pcl And Dmso2 Composites For Bio-Scaffold, Jae-Won Jang, Kyung-Eun Min, Cheolhee Kim, Chien Wern, Sung Yi

Mechanical and Materials Engineering Faculty Publications and Presentations

The significance of rheology in the context of bio three-dimensional (3D) printing lies in its impact on the printing behavior, which shapes material flow and the layer-by-layer stacking process. The objective of this study is to evaluate the rheological and printing behaviors of polycaprolactone (PCL) and dimethyl sulfone (DMSO₂) composites. The rheological properties were examined using a rotational rheometer, employing a frequency sweep test. Simultaneously, the printing behavior was investigated using a material extrusion 3D printer, encompassing varying printing temperatures and pressures. Across the temperature range of 120–140 °C, both PCL and PCL/DMSO₂ composites demonstrated liquid-like behavior, …

Artificial Neural Network-Based Modelling For Yield Strength Prediction Of Austenitic Stainless-Steel Welds, Sukil Park, Cheolhee Kim, Namhyun Kang

Mechanical and Materials Engineering Faculty Publications and Presentations

This study aimed to develop an artificial neural network (ANN) model for predicting the yield strength of a weld metal composed of austenitic stainless steel and compare its performance with that of conventional multiple regression and machine learning models. The input parameters included the chemical composition of the nine effective elements (C, Si, Mn, P, S, Ni, Cr, Mo, and Cu) and the heat input per unit length. The ANN model (comprising five nodes in one hidden layer), which was constructed and trained using 60 data points, yielded an R² value of 0.94 and a mean average percent error …

Can Smart Supply Chain Bring Agility And Resilience For Enhanced Sustainable Business Performance?, Mahak Sharma, Rose Antony, Ashu Sharma, Tugrul Daim

Engineering and Technology Management Faculty Publications and Presentations

Purpose

Supply chains need to be made viable in this volatile and competitive market, which could be possible through digitalization. This study is an attempt to explore the role of Industry 4.0, smart supply chain, supply chain agility and supply chain resilience on sustainable business performance from the lens of natural resource-based view.

Design/methodology/approach

The study tests the proposed model using a covariance-based structural equation modelling and further investigates the ranking of each construct using the artificial neural networks approach in AMOS and SPSS respectively. A total of 234 respondents selected using purposive sampling aided in capturing the industry practices …

Imaging Of Structural Timber Based On In Situ Radar And Ultrasonic Wave Measurements: A Review Of The State-Of-The-Art, Narges Pahnabi, Thomas Schumacher, Arijit Sinha

Civil and Environmental Engineering Faculty Publications and Presentations

With the rapidly growing interest in using structural timber, a need exists to inspect and assess these structures using non-destructive testing (NDT). This review article summarizes NDT methods for wood inspection. After an overview of the most important NDT methods currently used, a detailed review of Ground Penetrating Radar (GPR) and Ultrasonic Testing (UST) is presented. These two techniques can be applied in situ and produce useful visual representations for quantitative assessments and damage detection. With its commercial availability and portability, GPR can help rapidly identify critical features such as moisture, voids, and metal connectors in wood structures. UST, which …

Performance-Based Risk Assessment For Large-Scale Transportation Networks, Anteneh Deriba, David Y. Yang

Student Research Symposium

Efficiently assessing the risk of asset failure due to deterioration or extreme events is crucial for transportation asset management. Traditional methods often lack effectiveness in directly evaluating system performance-based risks, facing challenges like the exponential increase in system states and the emergence of low-probability high-consequence events ("grey swan" events). To address these, this paper introduces a novel performance-based risk assessment approach for large-scale transportation networks, inspired by the Transitional Markov Chain Monte Carlo (TMCMC) method. This method transforms the risk assessment problem into a high-dimensional posterior distribution, with system risk acting as the normalization factor (evidence). It also provides risk-based …

Comparative Life Cycle Assessment Of Hydrogen Production Via Various Pv-Assisted Electrochemical Water Splitting Techniques, Achyuth Ravilla

Student Research Symposium

Photoelectrochemical (PEC) and photovoltaic-electrochemical (PV-EC) water-splitting technologies have emerged as cost-effective options for large-scale green hydrogen production in industrial applications. Solar to hydrogen (STH) efficiencies of these technologies have reached up to 20% and several pathways have been explored to drive down the cost of hydrogen using these technologies to less than $2/kg. However, the environmental impact assessment of these technologies for industry-scale deployment has not been explored in previous studies. This study assesses the environmental impacts of PEC and PV-EC technologies by conducting a cradle-to-gate life cycle assessment. The functional unit considered for this assessment is 1 kg of …

Flexible Strain Gauge Sensors As Real-Time Stretch Receptors For Use In Biomimetic Bpa Muscle Applications, Rochelle Jubert

Student Research Symposium

This work presents a novel approach to real-time length sensing for biomimetic Braided Pneumatic Actuators (BPAs) as artificial muscles in soft robotics applications. The use of artificial muscles enables the development of more interesting robotic designs that no longer depend on single rotation joints controlled by motors. Developing robots with these capabilities, however, produces more complexities in control and sensing. Joint encoders, the mainstay of robotic feedback, can no longer be used, so new methods of sensing are needed to get feedback on muscle behavior to implement intelligent controls. To address this need, flexible strain gauge sensors from Portland company, …

Characterization Of Chopped Carbon Fiber Reinforced Composites Produced Using Fused Deposition Modeling, Jonathon Tran, Rachel Shubella

Student Research Symposium

Fused deposition modeling (FDM) is an additive manufacturing (AM) process which can create parts with complex geometries in their final shape without need for additional specialized tools or devices. The FDM process builds parts by adding material layer by layer only where it is needed, saving energy, costs, production time for complex parts, and minimizing waste. Fiber reinforcement can significantly enhance the mechanical properties of a polymer material and depends significantly on the fiber length distribution and fiber orientation distribution of the final part. In this research, we investigated the various infill patterns of FDM printed Markforged onyx which is …

Pulse Modulation In Braided Pneumatic Actuators Mimics Contractile Behavior Of Biological Muscles, Mohamad Elzein

Student Research Symposium

Advancements in robotics and bioengineering aim to emulate biological muscle systems through robotic actuators, blending mechanical strength with biological adaptability. A lesser-explored aspect is mimicking the pulse-like control characteristic of biological muscles, which contract in response to action potentials from motoneurons, with muscle contractile force relying heavily on the timing between these potentials. This study explores the effect of pulse lengths and the gaps between pulses on braided pneumatic actuators (BPAs), which mimic the nonlinearity and dynamic response of biological muscles. It hypothesizes that artificial muscles utilizing pulse-based control will exhibit a similar force dependency on the intervals between pulses …

Self-Balancing Robot Leg, Ben Bolen

Student Research Symposium

Research in the Agile and Adaptive Robotics Lab involves the creation of biomimetic robots. To this end, we developed a self-balancing robot leg actuated with braided pneumatic actuators (BPAs)—a type of pneumatic artificial muscle. These BPAs, akin to human muscles, exhibit properties such as high strength-to-weight ratio and tunable passive stiffness. An Inertial Measurement Unit (IMU) was placed on top of the tibia for feedback and the tibia and foot were connected with a hinge joint. The orientation of the ankle joint was controlled with an Arduino microcontroller sending commands to the proportional pressure valves supplying the BPAs. Leg balance …

Reducing Switching Noise And Losses In Two-Stage Electric Power Converters, Abhijeet Prem

Student Research Symposium

Advancements in semiconductor devices are enabling the design of better electrical power converter systems. Wide Bandgap (WBG) switching devices from Silicon Carbide and Gallium Nitride can operate at high temperatures, voltages, and frequencies with faster turn-on/off periods, improving converter performance over silicon devices. However, WBG technology is still new, and the rapid switching transitions of these devices lead to issues such as voltage overshoots, ringing, and electromagnetic interference, which need to be addressed for widespread adoption. This work introduces a new control method for reshaping the switching voltages, which overcomes the disadvantages of fast transition time without increasing the system's …

Plasma Ion Source, Nathan K. Davis

Student Research Symposium

It is well known that a plasma can be created with both high input power and ultra low pressure. The challenge is in creating these same plasma characteristics with both lower power while maintaining a higher pressure. We have developed an ion beam by careful manipulation of magnetic and electric fields. Magnetic fields are used to accelerate ambient electrons to ionize the low pressure gas into a plasma. Electric fields are used to extract the ions into a focused beam. To achieve these initial ionizations, an artificial vacuum is created to reach low enough pressures to ionize the gas. A …

Comparative Life Cycle Assessment Of Recycling Processes For Perovskite Solar Cells, Juan P. Herrera, Jules Freeman, Achyuth Ravilla, Ilke Celik

Student Research Symposium

Perovskite solar cells (PSCs) have emerged as a promising option for solar energy generation. However, it is essential to consider the environmental impact of these innovative photovoltaic (PV) technologies as the industry moves towards commercialization. Researchers are currently exploring ways to recycle PSCs to recover valuable materials and reduce their environmental impact at the end of their life. To ensure the sustainability of PSCs, this study evaluates and compares the environmental impacts of five recently developed recycling approaches. The Tool for Reduction and Assessment of Chemicals (TRACI) method was utilized to measure environmental impacts in categories such as acidification (kg …

Deriving Analytical Design Constraints For Absolute & Relative Encoding Schemes In Functional Subnetworks, Cody W. Scharzenberger-Braet, Alexander Hunt

Student Research Symposium

As neural networks have become prolific solutions to modern problems, there has been a congruent rise in the popularity of the numerical machine learning techniques used to design them. While they are highly generalizable, numerical methods tend to produce networks that act as inscrutable “black boxes,” making it difficult to interpret their behavior. One solution to the problem of network transparency is to use analytical techniques, but these methods are underdeveloped compared to their numerical alternatives. In order to enhance the viability of analytical techniques, this work extends previous efforts to quantify the impact that non-spiking neural encoding schemes have …

An Adaptive Large Neighborhood Search For The Multi-Vehicle Profitable Tour Problem With Flexible Compartments And Mandatory Customers, Vincent F. Yu, Nabila Yuraisyah Salsabila, Aldy Gunawan, Anggun Nurfitriani Handoko

Civil and Environmental Engineering Faculty Publications and Presentations

The home-refill delivery system is a business model that addresses the concerns of plastic waste and its impact on the environment. It allows customers to pick up their household goods at their doorsteps and refill them into their own containers. However, the difficulty in accessing customers’ locations and product consolidations are undeniable challenges. To overcome these issues, we introduce a new variant of the Profitable Tour Problem, named the multi-vehicle profitable tour problem with flexible compartments and mandatory customers (MVPTPFC-MC). The objective is to maximize the difference between the total collected profit and the traveling cost. We model the proposed …

Electron-Phonon Interaction Mediated Gigantic Enhancement Of Thermoelectric Power Factor Induced By Topological Phase Transition., Zhi Li, Koushik Pal, Huiju Lee, Chris Wolverton, Yi Xia

Mechanical and Materials Engineering Faculty Publications and Presentations

We propose an effective strategy to significantly enhance the thermoelectric power factor (PF) of a series of 2D semimetals and semiconductors by driving them toward a topological phase transition (TPT). Employing first-principles calculations with an explicit consideration of electron-phonon interactions, we analyze the electronic transport properties of germanene across the TPT by applying hydrogenation and biaxial strain. We reveal that the nontrivial semimetal phase, hydrogenated germanene with 8% biaxial strain, achieves a considerable 4-fold PF enhancement, attributed to the highly asymmetric electronic structure and semimetallic nature of the nontrivial phase. We extend the strategy to another two representative 2D materials …

Meso-Scale Seabed Quantification With Geoacoustic Inversion, Tim Sonnemann, Jan Dettmer, Charles W. Holland, Stan E. Dosso

Electrical and Computer Engineering Faculty Publications and Presentations

Abstract Knowledge of sub-seabed geoacoustic properties, for example depth dependent sound speed and porosity, is of importance for a variety of applications. Here, we present a semi-automated geoacoustic inversion method for autonomous underwater vehicle data that objectively adapts model inference to seabed structure. Through parallelized trans-dimensional Bayesian inference, we infer seabed properties along a 12 km survey track on the scale of about 10 cm and 50 m in the vertical and horizontal, respectively. The inferred seabed properties include sound speed, attenuation, density, and porosity as a function of depth from acoustic reflection coefficient data. Parameter uncertainties are quantified, and …

On The Feasibility Of Ultrasonic Full Waveform Evaluation With Changing Testing Conditions For The Quality Control Of Manufacturing Parts, Simon Schmid, Thomas Schumacher, Christian U. Grosse

Civil and Environmental Engineering Faculty Publications and Presentations

Fast volumetric non-destructive testing methods are needed, especially for quality control in manufacturing lines. Ultrasonic testing with full waveform evaluation is a promising method for this. However, changes in coupling conditions or environmental factors can significantly alter the ultrasound signal, sometimes more than actual defects. This study investigates the effect of various factors on the ultrasound signal based on a Monte Carlo study with wavefield simulations. The test specimens comprise aluminium plates with holes of varying sizes and positions. Using both experimental as well as simulated data, the performance of two commonly used comparison metrics, namely the R2 score and …

Inertial Particle Clustering Due To Turbulence In An Air Jet, Bianca Viggiano, Kris Gish, Stephen Solovitz, Raul Bayoan Cal

Mechanical and Materials Engineering Faculty Publications and Presentations

Explosive volcanic eruptions create turbulent plumes of fine ash particles. When these particles collide in the presence of moisture and electrostatic fields they combine into larger aggregates, which can significantly change the atmospheric residence time of the airborne cloud. Previous studies have suggested that turbulence may lead to preferential concentration—also known as clustering—of particles within the flow, increasing the likelihood of collisions and aggregation. Few experimental studies have quantified these processes for volcanic plumes. This behavior was investigated using a particle-laden air jet. By systematically varying the exit speed and the size, density, and concentration of particles, flows were produced …

First-Principles Calculations Of Lattice Thermal Conductivity In Tl,3Vse4: Uncertainties From Different Approaches Of Force Constants, Zhi Li, Yi Xia, Chris Wolverton

Mechanical and Materials Engineering Faculty Publications and Presentations

Accurate and reliable first-principles simulations of lattice thermal conductivity (κL) of highly anharmonic crystals have long been challenging in condensed matter and materials physics. With recent theoretical advances, the calculation of κL has evolved into a sophisticated process requiring the consideration of higher levels of refinements, such as high-order phonon-phonon scattering, anharmonic phonon renormalization, and heat transport beyond the phonon gas picture. Interatomic force constants (IFCs), however, as a shared pillar of the above concepts, are sometimes ambiguously implemented in this process, resulting in non-negligible uncertainties among different studies. Here, we revisit the ultralow κL of Tl3VSe4 and make a …

Numerical Study Of Cone Penetration In Calcareous Sands: Investigating Cone Tip Resistance Correction Factors For Crushable Soils, Stephanie Michelle Hyder

Dissertations and Theses

The cone penetration test (CPT) is used to characterize the behavior and properties of soils, including the susceptibility to earthquake liquefaction triggering. The cone tip resistance relates to liquefaction susceptibility through relative density, where relative density is closely related to both cone tip resistance and liquefaction susceptibility. Currently, published methods of estimating liquefaction potential (i.e., cyclic resistance ratio) are based on silica sands and do not properly characterize calcareous sands. The measured cone tip resistance in calcareous sands is lower than in silica sands at the same relative density; this difference is generally attributed to the higher compressibility of calcareous …

Comparison Of Conventional And Adaptive Acoustic Beamforming Algorithms Using A Tetrahedral Microphone Array In Noisy Environments, Megan Brittany Ewers

Dissertations and Theses

In situ acoustic measurements are often plagued by interfering sound sources that occur within the measurement environment. Both adaptive and conventional beamforming algorithms, when applied to the outputs of a microphone array arranged in a tetrahedral geometry, are able to capture sound sources in desired directions and reject sound from unwanted directions. Adaptive algorithms may be able to measure a desired sound source with greater spatial precision, but require more calculations and, therefore, computational power. A conventional frequency-domain phase-shift algorithm and a modified adaptive frequency-domain Minimum Variance Distortionless Response (MVDR) algorithm were applied to simulated and recorded signals from a …