Engineering Commons^™

An Injectable Thermosensitive Hydrogel Potentially Used For Wound Dressing With Self-Adhesive Properties, Yunxiu Qiu

McKelvey School of Engineering Graduate Student Theses & Dissertations

Wound healing is a complex process, and different kinds of materials are tried to achieve rapid healing. Among them, hydrogel is one of the best candidates for would dressing due to its distinctive properties, such as high biocompatibility, flexibility, and sensitivity to physiological environments. Injectable hydrogels can be facilely delivered in vivo without massive impairment to the body, as no surgical incision is needed for hydrogel embedment. This is highly consistent with the need of minimal invasion on human body. Multiple stimuli could be applied to achieve its injectability, including pH, temperature, light, ions in body fluids. Thermosensitive hydrogel is …

Mems 411: Lift Demonstration, Dean Ryan-Simmons, Marketa Riley, Puja Chhetri

Mechanical Engineering Design Project Class

A portable lift demonstration was requested to get children interested and thinking about what happens with fluid movement. The demonstration had size and weight requirements, which were both met. Accuracy of lift force representation was not requested, but simple force and flow visualizations were required. The demonstration had variable wind speeds, and showed the change in force with change in angle of attack.

Mems 411: Fast Pill Cutter, Andrew Brown, Isaac Sasser, Aaron Manuel, Quan Chau

Mechanical Engineering Design Project Class

This design project attempted to create a new pill-cutting device to help pharmacy technicians split pills quickly, precisely, and safely. The product was intended to occupy a competitive niche with current devices on the market, prioritizing increased cutting speed with potentially greater cost.

Mems 411: Portable Bridge Crane With Pulleys, Daniel Shen, Man Kit Mau, Haoxiang Lu, Kaijun Xu

Mechanical Engineering Design Project Class

The bridge crane demonstrates dynamics behavior that the flexible mode has a natural frequency depending on the string length. In this project, a portable bridge crane is designed and made to demonstrate this dynamical phenomena by changing speed and string length. The portable bridge crane requires a light mass and a small size. At the same time, because it needs to be observed in a two-dimensional plane, the trolley must be able to move horizontally on a bridge with tracks, and the speed of the trolley needs to be controlled by a speed controllable motor. The crane needs to suspend …

Mems 411: The Adjustable Bit Brace, Alex Levy, Alex Dutton, Daniel Luberda, Aidan Murphy

Mechanical Engineering Design Project Class

This group set out to create an open-source adjustable bit brace as a tool to lower the barrier to entry for smaller individuals looking to pick up tools and work on DIY projects. The brace is designed to highlight 3D printed parts, as well as components that can be fabricated at home by an experienced maker. The design uses standard adjustment mechanisms such as button clips and bolts to bring the bit brace from full size down to 2/3 scale in seconds. The device is advised by engineering models, FEA analysis, stiffness/strength targets, and destructive testing protocols to create a …

Mems 411: Creation Of A 3-Axis Camera System For Various Imaging Modalities, Ethan Meitz, Julia Flores, Ashley Linderman, Madison Larkin

Mechanical Engineering Design Project Class

The Lake Lab at Washington University in St. Louis faces challenges when setting up their camera systems for experiments. The Three Axis Camera system aims to optimize the experience by automating the movement and creating a user-friendly design. The current set-up requires the camera position to be adjusted manually and is “not liked” by most users. This wastes their time since the lab must set the location for the camera first and if the camera positioning is moved then the experiment will be ruined. Thus, the lab asked us specifically to help them automate these movements with our design and …

Mems 411: Compact Sewing Pin Dispenser, Jacob L. Weinstein, Eric Y. Lu, Nick J. Armanino

Mechanical Engineering Design Project Class

Sewing pins are small and hard to handle, and managing the pins can be very distracting (or painful) for a sewist. Our goal was to design a simple and easy sewing pin dispenser for a home sewist that can dispense small headed dressmaker pins. For our design to be a viable product, it would have to dispense pins very quickly, accurately, and safely. Additionally, it has to handle many pins at the same time so it does not have to be reloaded during use. Based on the design of a toothpick dispenser, our prototype small, lightweight, and portable device that …

Mems 411; Ground Work Station, Samuel Wille, Daniel Renbaum-Koss

Mechanical Engineering Design Project Class

This project aims to design a support mechanism for ecological field researchers who interact with plants and other samples from the forest floor for long periods. The design aims to recreate the functionality of bending over for long periods of time, while protecting the backs, hips and knees.

Mems 411: Portable Bridge Crane, Alex Eckels, Will Hurley, Zarya Desouza, Troy Bauer

Mechanical Engineering Design Project Class

The team designed and built a portable bridge crane for use in class demonstrations. The design was be based off a typical gantry crane, which consists of a trolley spanning across two horizontal parallel beams that are part of a gantry with a payload hanging from the trolley. The group also needed to design the gantry itself and ensure it was both stable enough to support the trolley and payload at the desired operation speeds as well as scaled properly for the desired use.

Mems 411: Portable Ground Work Station - Group C, Samantha Hudson, Valeria Pinedo Chipana, Valentina Harding, Luis Acosta

Mechanical Engineering Design Project Class

Build a ergonomic, portable, and weather resistant ground work station for members of the department of Biology to use during field research.

Mems 411: The Amazing Renewable Race, Kayla Murphy, Alitzel Yépiz, Daryl Wilson, Rebecca Davis

Mechanical Engineering Design Project Class

The project’s goal was to convey the importance of renewable energy to a 6 through 12 years old audience. This demo was designed to be installed at the St. Louis Science Center. To engage a younger audience, the renewable energy demonstration had to be interactive. As a result, a design similar to a carnival game was chosen. There are 3 stations that represent wind, hydroelectric, and solar energy. In this design, it is a multiplayer interactive race that portrays renewable energy. The initial design was to have each form of energy produced by the users. The user at the hydro …

Mems 411: The Pill Cutter, Alex Posly, Alex Austin, Drew Marolf, Dylan Stubbs

Mechanical Engineering Design Project Class

The goal of this design project was to improve the current method of pill cutting for STL Hills Pharmacy. Pharmacists and other medical professionals cut hundreds of pills weekly. Their current methods can only cut one pill at a time with an error rate of 50%. Pills are often split without enough precision and need to be thrown out. Our project was designed to have a 10% maximum error rate, require 1/4 of the force, and split pills 4 times as fast.

Mems 411: Ground Work Station Design Project, Jakub A. Gawedzki, Mark H. Wood, John B. Campoverde

Mechanical Engineering Design Project Class

Researchers from Washington University had requested us to design and develop a ground work station that allows them to work comfortable in the field for our senior design class.

Mems 411: Arliss Canister Vehicle, Patrick Smith, Brannon Boyd, Matthew Donaldson, Kieran Natarajan

Mechanical Engineering Design Project Class

To design, build, and test an autonomous canister vehicle to compete in the ARLISS competition. Design must autonomously drive to a given set of GPS coordinates, record and store GPS data during operation, survive a parachute drop, and traverse rough, uneven terrain.

Mems 411: Automatic Sewing Pin Dispenser, Edric Choi, Enrico Milletti, Adrian Odamtten, Chad Picerni

Mechanical Engineering Design Project Class

The aim of our project is to design and embody an automatic pin dispenser for our customer, Melanie, a recreational sewer. Namely, our pin dispenser design aims to address the need for sewers to safely receive and handle dressmaker pins with one hand whilst working with garments. We have identified three main performance goals for an automatic pins dispenser: Store at least 50 pins at a time, produce at least 1 pin every 2-3 seconds, and present at least 90% of all sorted pins in an upward orientation to the user. These performance goals were identified by interviewing our customer …

Mems 411: Self Lacing Shoes, Peter Pigatti, Bryce Roberts, Al-Amin Yusuf

Mechanical Engineering Design Project Class

For our senior design project we have chosen to design and prototype a pair of self lacing shoes with the initial target audience being people with disabilities who are limited in their ability to tie their own shoes for a variety of reasons. However, we hope that this product will catch on in popularity and become normalized for all people. These shoes will allow the wearer to easily slip them on and then secure the shoes to the foot with the push of a button rather than tying laces as in conventional shoes. This process will be driven by a …

Mems 411: St. Louis Science Center Vibration Station, Allie Periman, Hailey Hayes, Brian Higgins

Mechanical Engineering Design Project Class

Student groups work on an open-ended mechanical design problem and finish the semester with a physical prototype, a design report, and a presentation delivered to an external review board. Groups are guided through the engineering design process by completing a set of project deliverables. The quality of these deliverables provides a basis for the evaluation of individual and team performance. This course emphasizes the importance of user-centric design, communication and presentation skill, consideration of real-world constraints, sketching and creativity, prototyping, and data-driven decision-making using engineering models and analyses.

Mems 411: Dressmaker Pin Dispenser, Alex Goertz, Henry Holtz, Seamus Boyle, Youngjin Hong

Mechanical Engineering Design Project Class

The goal of this project was to design, manufacture, and test a machine which can dispense dressmaker pins in a consistent orientation, allowing the user can easily, and safely remove them one at a time. The purpose of the machine is to increase the efficiency and safety of sewers who may use dressmaker pins daily.

Mems 411: Lost Grains Winnower, Seth Jack, Matthew Finer, Alex Maggioni, Kristian Nilsen

Mechanical Engineering Design Project Class

This project involved designing an upgrade for the grain winnower in Dr. Mueller’s anthropology lab at Washington University in St. Louis. A winnower is a device that separates chaff from usable grain after harvesting and threshing. Many such devices exist, from industrial-scale winnowers sorting high volumes of grain to personal coffee bean winnowers. However, the constraints of the lab space and the specialized nature of the grain being winnowed presented specific constraints. An interview with Dr. Mueller was necessary to determine a ranked list of needs for use in the final product. After creating these rankings, a mock-up was used …

Computational Modelling Enables Robust Multidimensional Nanoscopy, Matthew D. Lew

Electrical & Systems Engineering Publications and Presentations

The following sections are included:

• Present State of Computational Modelling in Fluorescence Nanoscopy

• Recent Contributions to Computational Modelling in Fluorescence Nanoscopy

• Outlook on Computational Modelling in Fluorescence Nanoscopy

• Acknowledgments

• References

Deep Learning For Task-Based Image Quality Assessment In Medical Imaging, Weimin Zhou

McKelvey School of Engineering Graduate Student Theses & Dissertations

It has been advocated to use objective measures of image quality (IQ) for assessing and optimizing medical imaging systems. Objective measures of IQ quantify the performance of an observer at a specific diagnostic task. Binary signal detection tasks and joint signal detection and localization (detection-localization) tasks are commonly considered in medical imaging. When optimizing imaging systems for binary signal detection tasks, the performance of the Bayesian Ideal Observer (IO) has been advocated for use as a figure-of-merit (FOM). The IO maximizes the observer performance that is summarized by the receiver operating characteristic (ROC) curve. When signal detection-localization tasks are considered, …

Machine Learning Morphisms: A Framework For Designing And Analyzing Machine Learning Work Ows, Applied To Separability, Error Bounds, And 30-Day Hospital Readmissions, Eric Zenon Cawi

McKelvey School of Engineering Graduate Student Theses & Dissertations

A machine learning workflow is the sequence of tasks necessary to implement a machine learning application, including data collection, preprocessing, feature engineering, exploratory analysis, and model training/selection. In this dissertation we propose the Machine Learning Morphism (MLM) as a mathematical framework to describe the tasks in a workflow. The MLM is a tuple consisting of: Input Space, Output Space, Learning Morphism, Parameter Prior, Empirical Risk Function. This contains the information necessary to learn the parameters of the learning morphism, which represents a workflow task. In chapter 1, we give a short review of typical tasks present in a workflow, as …

Multifunctional Polydopamine Nanomaterials For Biomedical And Environmental Applications, Hamed Gholami Derami

McKelvey School of Engineering Graduate Student Theses & Dissertations

Polydopamine (PDA), a synthetic and organic material, has emerged as a promising materialplatform for various applications in energy, environmental, and biomedical fields. PDA, formed by self-polymerization of dopamine, is rich in catechol and amine groups, which facilitate covalent conjugation and/or other non-covalent interactions with organic and inorganic materials. It is highly biocompatible, biodegradable, has broadband light absorption spectrum and excellent light-to-heat conversion efficiency. Also, it is easy to synthesize and functionalize. The combination of excellent characteristics of polydopamine-based nanomaterials, make them a promising adsorbent agent for environmental wastewater treatment and photothermal agent for biomedical applications. In the first half of …

Optical And Physicochemical Properties Of Atmospherically Processed Brown Carbon Using Novel First-Principle Instrumentation, Benjamin Sumlin

McKelvey School of Engineering Graduate Student Theses & Dissertations

Atmospheric processing of brown carbon (BrC) – a class of spherical, internally-mixed, light-absorbing organic aerosol – emitted from smoldering biomass combustion is an understudied phenomenon with implications for climate science, air quality models, and satellite retrieval algorithms. BrC aerosols have received significant attention as a strong contributor to atmospheric light absorption in the shorter visible wavelengths and a driver of UV photochemistry. Their complex refractive indices (m=n+ik), size distributions, and carbon oxidation states dictate their optical properties, atmospheric residence times, and chemical interactions, respectively. There is currently a gap in our understanding of these fundamental particle properties and their evolution …

Uncovering The Roles And Evolved Sequence Grammar Of Hypervariable Intrinsically Disordered Proteins In Bacterial Cell Division, Megan Cohan

McKelvey School of Engineering Graduate Student Theses & Dissertations

Across all domains of life, a defining hallmark of the onset of cell division is the formation of a cytokinetic ring at the center of the cell. Cell division is a tightly controlled process that involves various regulatory factors that modulate the assembly of the cytokinetic ring. In rod-shaped bacteria, the ring is termed the Z-ring after the protein FtsZ, which is foundational to ring formation and is the bacterial homolog of tubulin. Like tubulin, FtsZ is an assembling GTPase, where GTP binding promotes the cooperative assembly into FtsZ polymers that laterally associate to form bundles. While the GTPase domain …

Autologous Stem Cell-Derived Β Cells For Diabetes Cell Replacement Therapy, Kristina G. Maxwell

McKelvey School of Engineering Graduate Student Theses & Dissertations

Autologous stem cell therapy is a promising treatment for patients with diabetes worldwide. Previous stem cell-derived β (SC-β) cell protocols were unable to efficiently differentiate multiple patient induced pluripotent stem cells (iPSCs) into stem cell-derived islets (SC-islets), containing insulin-secreting SC-β cells. Recent updates targeting the actin cytoskeleton have enabled the differentiation of 14 diabetic and nondiabetic stem cell lines into SC-islets. We used genetic engineering, specifically CRISPR/Cas9, to correct the diabetes-causing mutation in stem cells from patients with Wolfram Syndrome. The genetically engineered SC-β cells functioned and had a composition similar to nondiabetic SC-β cells, unlike the unedited SC-β cells …

Mechanical Strength Of Germanium Doped Low Oxygen Concentration Czochralski Silicon And The Effect Of Oxygen On Nitrogen Dissociation In Silicon, Junnan Wu

McKelvey School of Engineering Graduate Student Theses & Dissertations

During the Czochralski growth of silicon, it is inevitable for oxygen to be incorporated into the silicon crystal from the quartz crucible. Interstitial oxygen improves the mechanical strength of silicon by pinning and locking dislocations, but also generates thermal donors during device processes, shifting the electrical resistivity. For silicon wafers used in radio frequency (RF) applications, it is important to ensure the high resistivity of the substrates for good RF characteristics. Therefore, the oxygen level in these high resistivity silicon wafers is kept very low (< 2.5 × 1017 atoms/cm3) by carefully controlling the Czochralski growth conditions, in order to reduce the thermal donor concentration to an acceptable level. Silicon on insulator (SOI) substrates made from high resistivity wafers have been widely used for RF applications. SOI manufacturing includes multiple high temperature thermal cycles (1000 – 1100 °C), during which the high resistivity wafers are prone to slip and warpage. Therefore, it is technologically important to recover some of the lost mechanical strength due to the lack of oxygen by introducing electrically inactive impurities to suppress the dislocation generation and mobility in silicon. Germanium (Ge) as an isovalent impurity is 4% larger in size and forms a solid solution with silicon in the entire concentration range. Previous works have shown Ge doping at high concentrations above 6 × 1019 atoms/cm3 increased mechanical strength of silicon with high oxygen concentration (~ 1 × 1018 atoms/cm3). In this work, we explore the effect of Ge doping (7 - 9 × 1019 atoms/cm3) on the mechanical strength of low oxygen concentration (< 2 × 1017 atoms/cm3) silicon, where the oxygen associated dislocation locking and pinning are very low. A mechanical bending test was used to study the average dislocation migration velocity and the critical shear stress of dislocations motion at 600 – 750 °C for Ge doped, nitrogen doped, and undoped low oxygen samples, as well as nitrogen doped float-zone and un-doped high oxygen concentration samples. Next, we fabricated SOI substrates using these high resistivity wafers and compared their slip generation rates and the slip-free epitaxial grow temperature windows after the high temperature thermal cycles (> 1000 °C). Our results indicate at lower temperature Ge doesn’t affect the dislocation mobility …

Neural Dynamics, Adaptive Computations, And Sensory Invariance In An Olfactory System, Srinath Nizampatnam

McKelvey School of Engineering Graduate Student Theses & Dissertations

Sensory stimuli evoke spiking activities that are patterned across neurons and time in the early processing stages of olfactory systems. What features of these spatiotemporal neural response patterns encode stimulus-specific information (i.e. ‘neural code’), and how they are translated to generate behavioral output are fundamental questions in systems neuroscience. The objective of this dissertation is to examine this issue in the locust olfactory system. In the locust antennal lobe (analogous to the vertebrate olfactory bulb), a neural circuit directly downstream to the olfactory sensory neurons, even simple stimuli evoke neural responses that are complex and dynamic. We found each odorant …

Nanoscale Enhancement Of Photosensitized Radionuclide Stimulated Therapy, Daniel Douglas Lane

McKelvey School of Engineering Graduate Student Theses & Dissertations

Photodynamic therapy (PDT) provides efficient tumor killing through the generation of reactive oxygen species (ROS) from the optical excitation of a photosensitizer (PS). Furthermore, this mechanism is highly immune stimulating, providing systemic tumor immunity with a reduction in metastasis. However, these materials had previously been limited by their dependence upon external light sources, allowing treatment of only laser-accessible malignancy. With the recent development of photosensitized radiation stimulated therapy (PRaST) this depth dependence is broken through co-localization of radionuclides and semiconducting photosensitizers. This dissertation focuses on the enhancement of titanium dioxide (TiO2) based PRaST agents through understanding of TiO2 material parameters …

Evaluating The Structural And Functional Consequences Of Traumatic Joint Injury And Their Relation To Nf-Κb In A Non-Invasive Model Of Post-Traumatic Osteoarthritis, Ian Matthew Berke

McKelvey School of Engineering Graduate Student Theses & Dissertations

Post-traumatic osteoarthritis (PTOA) is a painful and debilitating disease of the synovial joint, characterized by degenerative changes to various joint tissues following traumatic joint injury. While several risk factors have been identified in the symptomatic progression of PTOA following injury, inflammation and NF-κB mediated changes are believed to significantly contribute to symptomatic joint dysfunction and pain. However, the temporal presentation of these pro-inflammatory signals following clinically relevant injury and their relationship to the development of symptomatic disease have not been thoroughly investigated. Therefore, there exists a critical need to better understand how these early inflammatory events following injury may contribute …