Engineering Commons^™

Mems 411: Diving Bubbler, Yasmin Ruff, Maya Ghatalia, Selva Moslehikhah

Mechanical Engineering Design Project Class

Design an affordable, portable, and effective surface-breaking system tailored for the WashU Diving team.

Mems 411: Ball Bearing Sorting Device, Claudia Markel, Max Cusick, Tomás Collado

Mechanical Engineering Design Project Class

Ball bearings are an integral part of many products, including cars, planes, and appliances. However, when bearings of multiple sizes and materials are mixed together, they can be difficult to separate quickly. Sorting the ball bearings becomes even more of a challenge for people who are not able to see the difference in color to discern the materials. To solve this problem, a ball bearing sorter, which can separate bearings of 1 2 in and 1 4 in for the materials of steel, brass, and plastic, was created. This project was based on the American Society of Mechanical Engineers 2024-2025 …

Mems 411: Asme Ball Bearing Sorter, Gurks Bansal, Natalia Klim, Helen Ma

Mechanical Engineering Design Project Class

Design and create a device that sorts ball bearings of 3 different materials and 2 different sizes for the 2024-2025 ASME Student Design Competition.

Mems 411: Custom Surfacing Machine, Katherine Minielly, Gaelen Clayton, Estela Villacis

Mechanical Engineering Design Project Class

Our project is in partnership with DeepSight, a startup working to revolutionize medical imaging through proprietary ultrasound sensing technology. Our objective is to create a custom surfacing machine to finish a critical ultrasound component. DeepSight’s new ultrasound system includes an aluminum component that requires a high degree of perpendicularity and a sub-micron finish on one side. DeepSight provided us with an existing grinding machine to retrofit to surface the aluminum part. Our goals were a surface roughness ofmicron, a surface perpendicularity ofmicrons, and the ability to process 3 parts inpart’s surface and ensure even surface wear. The part spins on …

Human-Aware Motion Planning For Aerial Robots, Beichen Zhou

McKelvey School of Engineering Graduate Student Theses & Dissertations

This project shows a combination for drones autonomous navigation in dynamic environments. The algorithm combine Social GAN SGAN for human trajectory prediction with Rapidly-exploring Random Tree Star RRT* for path planning. The objective is to efficiently and safe navigate in the area with human. Drones would avoid moving human and maintaining optimal flight path. During training SGAN model, we use both public datasets and dataset collected in the lab, which improve its adaptability in the lab. This experiment was tested through simulations and real-word experiment. SGAN provided a good prediction of human trajectories, which help drones to adjust their path. …

A Low-Cost Microvascular Phantom For Photoacoustic Imaging Using Loofah, Jinhua Xu

McKelvey School of Engineering Graduate Student Theses & Dissertations

Existing photoacoustic phantoms are inadequate for mimicking the complex microvascular structures found in human tissue due to their inability to replicate varying sizes and distri- butions of vasculature. This limitation underscores the need for a new material capable of replicating intricate microvascular networks. In this thesis, we introduce loofah as a novel natural phantom material with complex fiber networks ranging from 50 to 400 μm, enabling the fabrication of phantoms with controlled optical properties comparable to those of human microvasculature.

By incorporating a controllable chromophore into the loofah material, we adjusted its ab- sorption properties to match desired specifications. The …

Ellipticity-Controlled Exceptional Points From Nanoscale Metasurfaces, Benjamin Goldberg

McKelvey School of Engineering Graduate Student Theses & Dissertations

Precise control over light polarization is critical for advancing technologies in telecommunica- tions, quantum computing, and image sensing. However, existing methods for manipulating polarization around exceptional points in non-Hermitian systems, have exclusively focused on circular polarization and work with reflected light. To address this limitation, we de- velop a novel metasurface platform with high-Q resonators that enables tunable control of polarization exceptional points across arbitrary ellipticity for transmitted light. Our design uses orthogonally polarized guided mode resonators in a two-layer silicon metasurface, where careful tuning of the dipolar guided mode resonances (DGMRs) and layer spacing allows us to control the …

Characterizing Locust Anemotaxis: The Impact Of Sensory Perturbations On Flight Behavior, Yi-Xiao Huang

McKelvey School of Engineering Graduate Student Theses & Dissertations

This thesis investigates the effects of sensory perturbations on locust flight behavior, with the goal of better understanding how locusts integrate multiple sensory inputs to maintain flight control. Through a series of experiments, locusts were subjected to visual impairment, turbulent wind conditions, mechanical impairments of their wings and antennae, and pheromonal interference. These perturbations allowed for the exploration of the contributions each sensory pathway makes to flight stability and navigation in a controlled environment.

Results show that while visual impairment does not significantly impact average flight speed, it increases variability in flight stability, suggesting that visual cues are important for …

Towards Verified Vision-Based Neural Network Controllers For Autonomous Lane-Following, Xinhang Ma

McKelvey School of Engineering Graduate Student Theses & Dissertations

Vision-based neural network controllers have shown promising results in autonomous lane-following tasks, but verifying their safety properties remains a significant challenge due to the high dimensionality of image inputs. This thesis designs an approach to enable formal verification of vision-based lane-following controllers by first developing an end-to-end autonomous system combining deep learning-based lane detection with reinforcement learning control. To enable formal verification, we introduce a generator-based framework that bridges the gap between high-dimensional image space and low-dimensional vehicle states, allowing us to leverage existing verification tools while maintaining the vision-based nature of the controller.

We further enhance our verification framework …

Work-Stealing Scheduler For Parallel Cache-Adaptive Algorithms, Chuqi Jiang

McKelvey School of Engineering Graduate Student Theses & Dissertations

Modern computing systems with hierarchical memory structures, such as multiple cache levels, main memory, and external storage, pose significant challenges in optimizing memory usage for algorithm efficiency. Traditional models like the Disk Access Model (DAM) and advancements such as cache-oblivious algorithms have focused on minimizing memory transfers without requiring explicit knowledge of memory hierarchy parameters. However, these approaches assume fixed memory sizes and exclusive cache access, limiting their applicability in real-world, shared-memory environments where memory allocations fluctuate. To address these limitations, cache-adaptive algorithms were developed to dynamically adjust to changing memory profiles, enabling near-optimal performance even in multi-process systems. While …

Nonequilibrium Plasma Synthesis And Processing Of Iii-Nitride Materials, Dillon Patrick Moher

McKelvey School of Engineering Graduate Student Theses & Dissertations

Nitrogen is abundant on Earth as its diatomic form, and human activity has generated a significant demand for nitrogen-containing compounds. However, its triple bond energy of 941 kJ/mol makes it a poor reactive species in the ground state. Nitrogen-containing nonequilibrium plasmas are made up of background gas, electrons, ions, and a multitude of excited states of nitrogen or even atomic nitrogen. Many of these species have rather high reactivity. As such, the plasma medium is of great potential for driving chemical reactions that involve nitrogen as a reactant, i.e., nitrogen fixation into compounds like ammonia, high-energy-density polynitrogen compounds, and metal-nitride …

Nonequilibrium Plasma Synthesis And Processing Of Iii-Nitride Materials, Dillon Patrick Moher

McKelvey School of Engineering Graduate Student Theses & Dissertations

Nitrogen is abundant on Earth as its diatomic form, and human activity has generated a significant demand for nitrogen-containing compounds. However, its triple bond energy of 941 kJ/mol makes it a poor reactive species in the ground state. Nitrogen-containing nonequilibrium plasmas are made up of background gas, electrons, ions, and a multitude of excited states of nitrogen or even atomic nitrogen. Many of these species have rather high reactivity. As such, the plasma medium is of great potential for driving chemical reactions that involve nitrogen as a reactant, i.e., nitrogen fixation into compounds like ammonia, high-energy-density polynitrogen compounds, and metal-nitride …

Impacts Of Phosphate And Residual Free Chlorine On The Precipitation, Stability And Dissolution Of Lead Corrosion Products, Yao Ma

McKelvey School of Engineering Graduate Student Theses & Dissertations

Lead release from lead pipes into drinking water is a critical threat to public health. Orthophosphate addition is an established method of controlling lead concentrations in tap water. Many phosphate-based inhibitors currently used by utilities are blends of orthophosphate and polyphosphate. Orthophosphate can limit lead release from pipes by forming low-solubility lead phosphate solids on pipe inner surfaces. In contrast, polyphosphate can accelerate lead release by forming soluble lead-phosphate complexes. Due to the potential conversion from polyphosphate to orthophosphate in the distribution system and to complex dynamics of water chemistry in lead service lines (LSLs), the net impact of a …

Synthesis Of Neuronal Network Dynamics For Optimal Stimulus Encoding And Retention, Bethanna Thompson

McKelvey School of Engineering Graduate Student Theses & Dissertations

A central goal in neuroscience is to understand the relationship between the structure and activity of the brain and the resulting experience of thought and behavior that the brain underpins. Within this goal is the specific study of working memory: the process of storing, managing, and integrating incoming sensory information in the context of ongoing tasks. The process of working memory is foundational to higher cognition and reasoning, determining how we comprehend and interact with the world around us. The neural circuits responsible for working memory are seemingly able to store and process afferent stimuli with other recent or relevant …

Incorporating Genai Into Information Literacy Instruction: Find Engineering Standards, Lauren Todd

Generative AI Teaching Activities

Students will prompt GenAI tools to find relevant engineering standards that might apply to their mechanical engineering design project, then they must evaluate the responses.

A Limited-Preemption Scheduling Model Inspired By Security Considerations, Benjamin Standaert, Fatima Raadia, Marion Sudvarg, Sanjoy Baruah, Thidapat Chantem, Nathan Fisher, Christopher Gill

Computer Science and Engineering Faculty Research

Safety-critical embedded systems such as autonomous vehicles typically have only very limited computational capabilities on board that must be carefully managed to provide required enhanced functionalities. As these systems become more complex and inter-connected, some parts may need to be secured to prevent unauthorized access, or isolated to ensure correctness.

We propose the multi-phase secure (MPS) task model as a natural extension of the widely used sporadic task model for modeling both the timing and the security (and isolation) requirements for such systems. Under MPS, task phases reflect execution using different security mechanisms which each have associated execution time costs …

Enhancing Ammonium And Bicarbonate Tolerance In Chlorella Sorokiniana Through Ems-Induced Mutagenesis, Wentao Yang

McKelvey School of Engineering Graduate Student Theses & Dissertations

This study explores the enhancement of ammonium and bicarbonate tolerance in Chlorella sorokiniana via EMS-induced mutagenesis, aimed at improving the microalgae's resilience and growth under high-stress conditions of elevated NH4+ and HCO3 concentrations. By mutating C. sorokiniana using EMS, we developed mutant strains capable of thriving in conditions that are inhibitory to the wild type strain. The successful adaptation of these strains demonstrates a significant increase in biomass production and tolerance to environmental stressors, highlighting the potential of EMS mutagenesis in industrial algal applications for sustainable biofuel production and environmental remediation.

Beyond Measures Of Speed & Accuracy: Evaluating Visualization Perception, Reasoning & Decision-Making, Melanie Bancilhon

McKelvey School of Engineering Graduate Student Theses & Dissertations

Visualizations have long been used to support decision-making across various fields. By transforming complex data into graphical representations, such as charts, graphs, and maps, visualizations are generally reputed to make information more accessible and comprehensible for all. While prior work demonstrates that visualizations can improve speed and accuracy across comprehension and analytical tasks, there lacks research on how they can benefit decision-making. Decision-making is a complex task which involves risk comprehension and rational thinking but also various heuristics and external factors. While research has shown that individual traits and situational factors can impact performance with visualizations, they have not been …

Utilization Of Sodium Flame Synthesis For The Formation And Deposition Of Pure Metal Materials For Applications In Additive Manufacturing, Zachariah Wargel

McKelvey School of Engineering Graduate Student Theses & Dissertations

Advanced material classes, such as high temperature alloys, ceramics, and refractory materials have become a key area of focus for expansion in the realm of additive manufacturing. Factors such as high melting points, material homogeneity, and physical properties such as ductility limit the application of popular additive manufacturing methods to these material classes. By utilizing sodium flame synthesis and deposition (SFD) technology, nanoparticle materials can be synthesized via combustion in a laminar co-flow diffusion burner and impacted such that the deposits can be used to manufacture designed components. By using the applicable precursor materials of metal chlorides and elemental sodium …

Designing Behavior-Aware Ai Systems To Influence Human Decision-Making, Guanghui Yu

McKelvey School of Engineering Graduate Student Theses & Dissertations

Artificial intelligence (AI) demonstrates superiority over humans in many applications, such as image processing, speech recognition, and decision-making. AI systems are more efficient and accurate in information processing and computation, making them invaluable in assisting human decision-making across domains like healthcare, finance, and academia. Despite these strengths, real-world applications often involve complex, context-specific judgments and a deep understanding of human values, which current AI systems might not fully grasp. In domains requiring creativity and critical thinking, AI systems heavily rely on existing human knowledge. Humans, however, possess unique strengths such as intuition, which aids decision-making in uncertain or novel situations, …

Mechanochemical Correlations And Spatial Distribution Of Components In Plant Cell Walls And Extracellular Matrices, Huiyong Li

McKelvey School of Engineering Graduate Student Theses & Dissertations

Plant cell walls and extracellular matrices (ECMs) are important to cellular activities in plant/animal organs. The organization of plant cell wall/ECM components (e.g., local composition, arrangement, and ultrastructure of cell wall/ECM polymers) plays a role in determining their local mechanical properties. As a result, the natural processes of cell and tissue growth, development, and function rely on the control of cell wall/ECM composition, arrangement, and ultrastructure to manipulate local mechanical properties. However, directly correlating cell wall/ECM composition, organization, and mechanics has been challenging. To overcome this barrier, one goal of this thesis is to develop probing methodologies at a sub-cellular …

Rational Design Of Lignin-First Biorefineries Through Lignin Analysis And Deconstruction Modeling Tools, Aditya Ponukumati

McKelvey School of Engineering Graduate Student Theses & Dissertations

Lignocellulosic biomass is produced photosynthetically from atmospheric CO2 and is one of the few sources of renewable, reduced carbon that is generated on a scale comparable to demand for chemical commodities. For a sense of scale, the U.S. Energy Security and Independence Act targets the production of approximately 16 billion gallons per year of second-generation lignocellulosic biofuels by 2025. That production would generate approximately 62 million tons per year of dry lignin byproducts. The focus of this dissertation is on the valorization of these lignin components of biomass. Currently, lignin is either discarded or burned for local heat or electricity …

Soft Electronics And Systems For Display And Healthcare Applications, Junyi Zhao

McKelvey School of Engineering Graduate Student Theses & Dissertations

Soft electronics are emerging as a revolutionary platform, signifying a pivotal shift from performance-centric priorities to human-centered principles that emphasize accessibility, sustainability, and user experience. As conventional electronics technology approaches its performance ceiling, further improvements in performance metrics have slowed, prompting consumers to place greater importance on user experience and eco-friendliness. Compared to traditional rigid electronics, soft electronics offer the potential to seamlessly integrate biological systems with soft electronic frameworks. Motivated by these demands, this dissertation has been dedicated to bridging fundamental material studies, advanced manufacturing, novel electronic devices, system-level integrations, and practical applications. This interdisciplinary endeavor aims to establish …

Activity: Students Find Conceptual Errors In Ai Output, Janie Brennan

Generative AI Teaching Activities

Instructor asks ChatGPT questions related to a key concept to find one where ChatGPT has conceptual errors. Ask students to find the errors and explain them.

Fundamental Limits In Measuring The Anisotropic Rotational Diffusion Of Single Molecules, Weiyan Zhou, Tingting Wu, Matthew D. Lew

Electrical & Systems Engineering Publications and Presentations

Many biophysical techniques, such as single-molecule fluorescence correlation spectroscopy, Förster resonance energy transfer, and fluorescence anisotropy, measure the translation and rotation of biomolecules to quantify molecular processes at the nanoscale. These methods often simplify data analysis by assuming isotropic rotational diffusion, e.g., that molecules wobble within a circular cone. This simplification ignores the anisotropy present in many biological contexts that may cause molecules to exhibit different degrees of diffusion in different directions. Here, we loosen this assumption and establish a theoretical framework for describing and measuring anisotropic rotational diffusion using fluorescence imaging. We show that anisotropic wobble is directly quantified …

Robust Quantitative Photoacoustic Imaging For Colorectal Cancer Treatment Monitoring, Sitai Kou

McKelvey School of Engineering Graduate Student Theses & Dissertations

Colorectal cancer is the 2nd leading cause of cancer death in the United States and the incidence among population under 50 years old has been increasing for the past decade. Contrary to obvious vascular and morphological structures in pre-treatment colorectal cancer, during treatment and post-treatment colorectal cancer tissue often contains fibrosis and edema in tumor bed. These complications cause difficulties in evaluating tissue response to neoadjuvant chemoradiation therapy with MRI and endoscopy, leading to unnecessary resection of rectum, which increases healthcare cost and impacts patient quality of life. Photoacoustic (PA) imaging is a promising tool for observing blood distribution in …

Jme 4110: Better Beach Wagon, Jalen Rhodes, Joshua Peters, Seth Peters, Jevonn Lewis-Harris

Washington University / UMSL Mechanical Engineering Design Project JME 4110

This project aims to add to a current beach wagon and improve effective movement through sand and concrete. Some beach wagons out in the market make it incredibly difficult to navigate through sand, often requiring more effort to push or pull. Some beach wagons solve these issues, such as electric beach wagons and their use of balloon tires; however, they are typically expensive, costing up to $2500.00. With Visionary Solutions’ design, the beach wagon will be able to move smoothly through both terrains (concrete and sand) and will be inexpensive to produce. The materials design includes polylactic acid (PLA) 3D …

Jme 4110: Stand-Up Pedicure Final Report, Heather Burt, Brian Hinkle, Jonathon Riggle, Anna Domingo Garcia

Washington University / UMSL Mechanical Engineering Design Project JME 4110

This project focuses on designing a pedicure device specifically for individuals who struggle with bending down to cut their toenails. While many people may not give this task a second thought, for some, it is a daily challenge. The goal is to create a device that allows users to safely and comfortably cut their toenails without needing to bend down or visit a nail salon, saving them time, effort, and money. This innovative design will cater to those with physical limitations, enabling them to maintain their nail care independently.

Jme 4110: Washer To Dryer Clothes Transfer Device, Scott Diep, Jared Edwards, Catherine Mcdonnell, Patrick Geldmeier

Washington University / UMSL Mechanical Engineering Design Project JME 4110

For those leading busy lives or facing mobility challenges, this project involve a custom device can transfer clothes from washer to the dryer automatically when the person is not home. This solution eliminates the need to manually move clothes from the washer, preventing formation of mildew, and ensuring that the laundry is fresh and ready to wear when you return.

Jme 4110: Inflatable Patient Wedge, Thomas Gunsten, Bushra Zaidi, Zachary Howell, Luke Prichard

Washington University / UMSL Mechanical Engineering Design Project JME 4110

The goal of this project was to design, model, and build an inflatable patient wedge, capable of lifting a patient from a laying position to an appropriate sitting position. This system had to be cheap, reliable, and strong enough to lift a wide range of different patients. The design of this project includes repurposed air mattresses, resealed with an epoxy, and shaped into an appropriately angled wedge.