Engineering Commons^™

Jme 4110: Patient Mat Mover, Muhammad Mughal, Seth Gallamore, Gabriel Monte, Marcos Navas Gallardo, Jamie Barvian

Washington University / UMSL Mechanical Engineering Design Project JME 4110

The idea of an improved patient mat mover was suggested to help make the life of patients and their care givers easier. The typical method of using brute force to lift a patient and slide a mat under them can be very challenging and tasking on both the patient and their care giver. It is a large inconvenience in the medical field and makes the process of patient care difficult and uncomfortable. Our value is designing a solution that will eliminate pain and difficulty for both our patients and their nurses/care givers by simplifying patient transport from bed to bed. …

Design And Characterization Of 3d-Printed Hydrogel Lattices With Consistent Structural And Mechanical Anisotropy, Daniel Yoon

McKelvey School of Engineering Graduate Student Theses & Dissertations

This thesis explores the use of 3D printing to fabricate soft hydrogel lattice structures with consistent properties, including varying levels of mechanical anisotropy. Magnetic resonance elastography (MRE) is a non-invasive imaging tool to estimate and characterize the mechanical properties of tissue. MRE “phantoms” (physical surrogate models) have been used to assess how well MRE can measure and estimate mechanical properties. While gel phantoms generally simulate brain tissue, almost all have been isotropic. Prior studies have shown that white matter brain tissue is structurally and mechanically anisotropic. To validate anisotropic MRE, phantoms with controllable, reproducible anisotropic material properties are needed. This …

Single-Molecule Orientation Imaging Reveals The Nano-Architecture Of Amyloid Fibrils Undergoing Growth And Decay, Brian Sun, Tianben Ding, Weiyan Zhou, Tara S. Porter, Matthew D. Lew

Electrical & Systems Engineering Publications and Presentations

Amyloid-beta (Aβ42) aggregates are characteristic Alzheimer’s disease signatures, but probing how their nanoscale architectures influence their growth and decay remains challenging using current technologies. Here, we apply time-lapse single-molecule orientation-localization microscopy (SMOLM) to measure the orientations and rotational “wobble” of Nile blue (NB) molecules transiently binding to Aβ42 fibrils. We correlate fibril architectures measured by SMOLM with their growth and decay over the course of 5 to 20 min visualized by single-molecule localization microscopy (SMLM). We discover that stable Aβ42 fibrils tend to be well-ordered and signified by well-aligned NB orientations and small wobble. SMOLM also shows that increasing order …

A Distributed And Hybrid Ai-Based Security Framework For 5g Real-Time Applications, Ali Ghubaish

McKelvey School of Engineering Graduate Student Theses & Dissertations

This dissertation develops a multifaceted security framework tailored for 5G-enabled real-time Internet of medical things (IoMT) systems to significantly enhance the security infrastructure within healthcare environments. The framework pivots around three core technological advancements: the development of the Light feature Engineering based on the Mean Decrease in Accuracy (LEMDA), the construction of a 5G testbed that serves as a distributed intrusion detection system (IDS), and the implementation of a hybrid deep reinforcement learning (HDRL) method. LEMDA represents a breakthrough in data processing for IoMT systems. By intelligently reducing data complexity, LEMDA enhances the speed and accuracy of threat detection mechanisms, …

Air Quality Assessment On Local And Hyperlocal Scales, Zhiyao Li

McKelvey School of Engineering Graduate Student Theses & Dissertations

Air quality monitoring across local and hyperlocal scales has attracted increased attention from both the public and research community. There are several approaches such as passive samplers and low-cost air quality sensors, depending on the pollutant and measurement objectives. Local and hyperlocal air pollutant measurements help to characterize local emission sources such as traffic and industry, including separating these signals from large scale influences (e.g., urban and regional scales), and better understand how land use types and meteorology influence pollutant spatiotemporal patterns. Low-cost sensors (LCS) are now a popular approach to monitor several criteria pollutants (e.g., particulate matter (PM), ozone, …

Coupling Treatment Technologies With Bioelectrochemical Systems To Optimize Resource Recovery From Wastewater, Matthew Stephen Ferby

McKelvey School of Engineering Graduate Student Theses & Dissertations

Wastewater is a common waste produced from municipal, agricultural, and industrial processes. As the world’s population increases, the amount of wastewater produced globally is expected to reach approximately 450 billion m3 in the next two decades. Issues surrounding water, food, and energy accessibility will also become more imminent as the population grows. Interestingly, wastewater is an unconventional source of resources including water, nutrients (e.g., NH4+ and PO43-), and energy. However, conventional wastewater treatment processes focus primarily on the removal of containments rather than the recovery of resources. Bioelectrochemical systems (BES) have the ability to recover resources from wastewater. These engineered …

Data-Driven Evaluation Of Deep Generative Models In Biomedical Imaging, Rucha Milind Deshpande

McKelvey School of Engineering Graduate Student Theses & Dissertations

Deep generative models (DGMs) have tremendous potential for several biomedical imaging applications such as data augmentation, image reconstruction, and image denoising. However, the deployment of DGMs in real-world biomedical imaging workflows without domain-relevant evaluations can jeopardize patient health and well-being. The evaluation of DGMs in biomedical imaging is challenging due to several factors: requirement of domain expertise for visual inspection, lack of a mathematically defined ground truth, and the unclear relevance of popular evaluation measures adopted from the computer vision literature. Given these challenges, one way to evaluate DGMs is via purposefully designed synthetic data. In this thesis, two frameworks …

Development, Numerical Simulation And Turbulence Modeling Of A Sustainable Transonic Truss-Braced Wing Aircraft Using Liquid Hydrogen Fuel And Active Flow Control, Bryce Zachary Thomas

McKelvey School of Engineering Graduate Student Theses & Dissertations

There is pressing need for emissions reduction and an increase in efficiency for the next generation of commercial aircraft in order to reduce the environmental impact of the aviation sector and combat global climate change. The implementation of alternative fuels as well as new engine and wing designs are actively being explored as methods to reduce emissions. This thesis analyzes the implementation of hydrogen fuel, a transonic truss braced wing and active flow controls as means to improve the performance of a medium range commercial airliner. The widespread adoption of cryogenic liquid hydrogen (LH2) fuel as a green alternative to …

Exploring Applications Of Artificial Intelligence In Water And Wastewater Management Systems, Yanran Xu

McKelvey School of Engineering Graduate Student Theses & Dissertations

Water and wastewater management systems play an essential role in satisfying residential, commercial, and industrial needs, but these systems suffer from undesired issues and high expenses, which stresses the need for sustainable development and system optimization. Modeling simulation is commonly used to optimize system performance through process prediction and precise control, and artificial intelligence (AI) technologies including machine learning (ML) and deep learning (DL) are showing their advantages in the application of water and wastewater management systems. A general framework was illustrated for optimized performance and enhanced explainability of ML models. Several analytical techniques were explored, including feature engineering, data …

Structural Dynamics Of The Human Brain In Vivo From Tagged Mri And Mr Elastography, Jordan De Niro Escarcega

McKelvey School of Engineering Graduate Student Theses & Dissertations

The underlying mechanics surrounding vulnerability of human brains in response to impact is critical to our ability to diagnose and treat traumatic brain injury (TBI), but our understanding of brain mechanical behavior is incomplete. Tagged MRI (tMRI) and magnetic resonance elastography (MRE) are two imaging techniques that are used to visualize and quantify deformation fields in human brains in vivo. The objective of this thesis is to gain a better understanding of brain vulnerability, by quantitively analyzing deformation fields extracted from in vivo human imaging studies. This was achieved through the following aims: (1) Extract mode shapes and natural frequencies …

Application Of Finite-State Wake Models To Rotors Re-Entering Their Own Wake, Michael Seay Morrow

McKelvey School of Engineering Graduate Student Theses & Dissertations

This paper details the development of a finite-state, dynamic wake model for the purpose of modeling a helicopter rotor reentering its own wake. This model stems directly from both the Peters-Morillo wake model to determine the velocity field on and above the helicopter rotor and the Peters-Fei model to compute the velocity field below the rotor. The specific case of nonzero net thrust was evaluated under assumptions of axial flow and potential flow theory. Results consist of computations of the inflow velocity for this case, along with comparison to closed-form, potential flow solutions for validation. The finite-state model is shown …

Improving And Modeling Heterogeneous Streaming Computation, Clayton Faber

McKelvey School of Engineering Graduate Student Theses & Dissertations

Data streaming algorithms are a class of problems that deal with moving data through a system while being processed. When implementing these types of algorithms a developer will spend time tuning an implementation for deployment, but if they are using heterogeneous architectures or when nodes of computation are physically separate from one another performance may be lost to unforeseen data movement complications. In this work we aim to alleviate some of these pain points through a combination of programming advice and mathematical models. One of the pain points often unseen and underappreciated by developers is a type of data streaming …

Data-Driven Insights Into Spatial Patterns And Disease Etiologies Of White Matter Hyperintensities, Sugandha Roy

McKelvey School of Engineering Graduate Student Theses & Dissertations

In this thesis, we have applied Orthogonal Projective Non-Negative Matrix Factorization (opNMF) to identify spatial patterns of white matter hyperintensities (WMH) within UK Biobank's imaging data. Our selection criteria excluded subjects with a history of neurological, mental, and specific cerebrovascular conditions, allowing us to focus on WMH patterns in a healthy aging population. We have interrogated the association of location-specific WMHs with a variety of demographic, clinical, and genetic factors. Our multivariable regression analysis evaluates the strength and nature of the associations between these factors and WMH distribution. The analysis integrates variables such as age, sex, smoking habits, medication usage …

Design And Analysis Of Passive Correlator Radio-Frequency Identification Tagging, Albert Kilgore

McKelvey School of Engineering Graduate Student Theses & Dissertations

Radio Frequency Identification (RFID) is a technology used in many industries to locate and track assets. Passive RFID tags are popular because they are inexpensive and flexible, but they have limited accuracy. My thesis aims to improve the accuracy of passive RFID tags by investigating two solutions: (a) Using orthogonal RFID configuration and exploiting phase information available to an RFID reader, in addition to the received signal strength indicator (RSSI) metric; and (b) Designing a novel voltage multiplier-based correlator circuit that can be integrated directly onto the tag. To further reduce power consumption and silicon area, we propose an architecture …

An Attention Lstm U-Net Model For Drosophila Melanogaster Heart Tube Segmentation, Xiangping Ouyang

McKelvey School of Engineering Graduate Student Theses & Dissertations

Machine learning is commonly used in biomedical image analysis, as it allows automated image segmentation and identification that minimizes the need for tedious human involvement. Drosophila melanogaster is often used as a cardiac disease model, where optical coherence microscopy (OCM) is used to image and analyze its beating dynamics. As OCM often generates a large volume of images, automated image segmentation is necessary to quantify the heart beating efficiently. Our most recent heart segmentation model, FlyNet 2.0+, is a fully convolutional LSTM U-Net model. However, the performance of the model diminishes in the presence of artifacts, such as image reflection …

Calcium Analysis Of Intercellular Communications Between Alpha Cells And Delta Cells Across The Pancreatic Islet, Shichao Gao

McKelvey School of Engineering Graduate Student Theses & Dissertations

The intricate communication between different cell types within pancreatic islets plays a crucial role in regulating glucose homeostasis. Among these cellular interactions, the interplay between α cells (responsible for glucagon secretion) and δ cells (secreting somatostatin) is particularly intriguing due to the inhibitory effects of somatostatin on glucagon release. Understanding the intercellular interactions between α and δ cells may provide insights into the mechanisms underlying the coordinated regulation of blood glucose levels. In this study, we employed a multi-modal approach combining confocal imaging, image analysis, and correlation network analysis to investigate the spatial relationships and potential functional connections between α …

The Conceptual Design, Analysis And Optimization Of A Hydrogen Combustion And A Hydrogen Fuel-Cell Powered Aircraft, Michael Kiely

McKelvey School of Engineering Graduate Student Theses & Dissertations

In the effort to combat climate change worldwide, the aviation industry faces particularly complex design challenges in designing new, emission free vehicles. One potential solution to this problem is the use of hydrogen fuel as a means of propulsion. Hydrogen fuel has many benefits over traditional jet fuel such as a higher gravimetric energy density; however, it requires the aircraft to carry large, pressurized, cryogenic fuel tanks. This thesis examines the design challenges, potential solutions, and the analysis methods for the design of a short to medium range hydrogen powered commercial airliner. To accomplish this goal, a comprehensive conceptual design …

Structured Light Radial-View Endoscope Imaging Development For Evaluation Of Human Tissue, Xiyan Li

McKelvey School of Engineering Graduate Student Theses & Dissertations

In this thesis, we improved an existing structured light methodology to more accurately estimate tissue optical properties imaged in a single snapshot. The developed approach is a major enhancement of the traditional three-phase spatial frequency domain imaging system: It greatly simplifies the operational procedure while also maintaining high accuracy in optical property measurements .

Leveraging this improved approach, we have developed a low-cost, compact, and radial-view endoscope prototype. This prototype combines affordability with high functionality and a user-friendly design. To assess the performance and reliability of our endoscope, we conducted comprehensive evaluations involving tissue-mimicking phantoms, as well as ex vivo …

Evaluating Neuroimaging Modalities In The A/T/N Framework: Single And Combined Fdg-Pet And T1-Weighted Mri For Alzheimer’S Diagnosis, Peiwang Liu

McKelvey School of Engineering Graduate Student Theses & Dissertations

With the escalating prevalence of dementia, particularly Alzheimer's Disease (AD), the need for early and precise diagnostic techniques is rising. This study delves into the comparative efficacy of Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) and T1-weighted Magnetic Resonance Imaging (MRI) in diagnosing AD, where the integration of multimodal models is becoming a trend. Leveraging data from the Alzheimer's Disease Neuroimaging Initiative (ADNI), we employed linear Support Vector Machines (SVM) to assess the diagnostic potential of these modalities, both individually and in combination, within the AD continuum. Our analysis, under the A/T/N framework's 'N' category, reveals that FDG-PET consistently outperforms T1w-MRI across …

Enhancing Fpga Synthesis For Space Applications: Performance Evaluation Of Scalehls In The Adapt Project, Ruoxi Wang

McKelvey School of Engineering Graduate Student Theses & Dissertations

This thesis investigates the application of ScaleHLS, a high-level synthesis (HLS) tool, to enhance Field-Programmable Gate Array (FPGA) synthesis for space applications, with a focus on the Antarctic Demonstrator Advanced Particle-astrophysics Telescope (ADAPT) project. The study explores how ScaleHLS optimizes the transformation of C code into FPGA-compatible designs to improve computational efficiency and resource utilization.

The research details the process of adapting ADAPT's computational algorithms for FPGA using ScaleHLS, emphasizing the tool's effectiveness in streamlining the code-to-hardware translation. A performance evaluation highlights significant improvements in resource management and operational speed, demonstrating the tool's impact on FPGA synthesis.

These findings illustrate …

Integrating Implantable Bci Devices Within Bci2000 Using A Unified Framework And Toolchain For In-Vivo Research, Dhruva Mehta

McKelvey School of Engineering Graduate Student Theses & Dissertations

The field of neurotechnology research has a bright and promising future as more devices are created. However, there are still many gaps in the field as the potential for neuromodulation grows. Devices such as the Micro-Leads StimZ system and the Ripple Grapevine/Summit system help bridge that gap by allowing for a broader variety of closed-loop neuromodulation experiments to be implemented thanks to their portability and versatility. Despite these devices being on the market, however, there needs to be a method to collaborate and interact with them across multiple research institutions. BCI2000 helps to address that by creating a standardized working …

Fabrication Of Two-Dimensional Material-Based Nano-Capacitors Using Bismuth Selenite (Bi2seo5) To Study Its Dielectric Properties, Major Kc

McKelvey School of Engineering Graduate Student Theses & Dissertations

In recent years, the demand for high-performance micro and nanodevices has surged, necessitating the exploration of novel dielectric materials to replace conventional silicon dioxide. Following the continuation of the Moorse law, as device dimensions reduce to nanoscale levels, the properties of silicon dioxide can degrade, leading to issues such as increased leakage current and reduced gate control. Materials with superior electrical properties, such as higher dielectric constant, lower leakage current, and better thermal stability allowing for the development of faster, more efficient, and more reliable devices are in higher demand than ever. Two-dimensional layered semiconductor nanomaterials represented by compounds such …

Robustness Of Trajectory Prediction Neural Network Models, Guocheng He

McKelvey School of Engineering Graduate Student Theses & Dissertations

The application of autonomous vehicles in real life relies on trajectory prediction models based on perception and observation of the surrounding scene. The deep neural network model has been widely proven to provide relatively stable and excellent performance in various scenarios. Many formal approaches are used as verification of the prediction results of DNN models, where Conformal Prediction is one which can provide statistical safety guarantee region for DNN models. However, so far, no research has shown that conformal prediction possesses satisfactory robustness in dealing with purposed adversarial attacks. In this paper, we propose an adversarial attack approach against trajectory …

Ammonia Recovery From Digester Centrate With Electrochemical Membrane Systems: Mechanism, Performance, And Application, Fubin Liu

McKelvey School of Engineering Graduate Student Theses & Dissertations

Nitrogen plays an indispensable role in living organisms and thus is a key element for agricultural production. Ammonia (NH3), as an important part in nitrogen cycle, can be synthesized by nitrogen fixing bacteria and the Haber-Bosch process, the latter of which requires an extensive energy input. Wastewaters can contain a large amount of nitrogen compounds because of kitchen and toilet wastes being discharged to sewage. The concentration of ammonia nitrogen (NH4+-N) can be hundreds mg per liter in some wastewaters like anaerobic digester (AD) centrate. However, both Haber-Bosch process and conventional wastewater ammonia treatment process are energy intensive, which making …

Design And Application Of Phase-Separating Peptides In Cytosolic Drug Delivery, Huihao Wang

McKelvey School of Engineering Graduate Student Theses & Dissertations

This research investigates the design and application of phase-separating peptides for direct cytosolic drug delivery. Novel peptides (GHGXY)4, with variable amino acids, were synthesized using microwave-assisted chemistry to enhance phase separation and membrane fusion. In vitro experiments utilizing advanced imaging techniques demonstrated the peptides' capability to form coacervates and facilitate direct cargo, DNA, mRNA, and protein, delivery into the cytosol, bypassing traditional cellular barriers. The study also explores the role of inhibitor Bafilomycin and NH4Cl in phase-separating peptides functionality, offering significant insights into their delivery mechanisms. This research underscores the potential of phase-separating peptides in improving therapeutic delivery strategies.

Environment And Response Of 3d-Encapsulated Mesenchymal Stem Cells To Mechanical Loading, Augustus Greenwood

McKelvey School of Engineering Graduate Student Theses & Dissertations

This thesis explores the micromechanical environment induced when cyclically compressing hydrogels via finite element modeling and experimentally on the impact of loading on mesenchymal stem cells (MSCs) when encapsulated withing 3D hydrogel matrices. Degenerative joint diseases, characterized by cartilage degradation, present significant challenges due to cartilage's limited self-repair capacity. Innovative approaches, including stem cell-based therapies and engineered biomaterials, have emerged as promising strategies for cartilage repair and regeneration. This work specifically investigates the calibration of a bioreactor, the uniformity of load response across the hydrogel constructs via finite element modeling (FEM), and the stress response of MSCs subjected to various …

Development Of A Wearable Short-Wave Infrared Photoplethysmography Device For Detection And Monitoring Of Hemodilution During Postpartum Hemorrhage, Hannah Gruensfelder

McKelvey School of Engineering Graduate Student Theses & Dissertations

ABSTRACT OF THE THESIS

A Thesis on the Development of a Wearable Short-Wave Infrared Photoplethysmography Device for Detection and Monitoring of Hemodilution During Postpartum Hemorrhage

by

Hannah Gruensfelder

Master of Science in Biomedical Engineering

Washington University in St. Louis, 2024

Professor Christine O’Brien, Chair

Postpartum hemorrhage (PPH), the leading cause of maternal death and morbidity, affects nearly 14 million people worldwide each year, disproportionally impacting racial minorities and people in low resource settings. A timely diagnosis of PPH is key in providing optimal patient care, as an estimated 90% of deaths due to PPH are preventable with early diagnosis and …

Numerical Simulations Of Supersonic/ Hypersonic Flows In Compression Corners And A Hypersonic Flow Study Of Atmospheric Entry Of Mars Science Laboratory Capsule, Dexter Allen

McKelvey School of Engineering Graduate Student Theses & Dissertations

This thesis consists of two related parts. The first part is the study of supersonic/hypersonic flow in compression corners. The compression corners are simple geometries but rich in flow-features that can be challenging for accurate prediction of their flow fields in high-speed compressible flow using the Reynold-Averaged Navier-Stokes (RANS) equations in conjunction with a turbulence model. At higher degrees of corner angles, there exists a shock-boundary layer interaction region which includes a significant recirculation zone in the corner. In this thesis, experimentally available test cases for compression corner at Mach 3, 8, and 11 at various corner angles are modeled …

Modeling Of Nk Cells In Pediatric Patients With Unusually Severe Or Recurrent Hsv Using High-Dimensional Flow Cytometry, Yunran Feng

McKelvey School of Engineering Graduate Student Theses & Dissertations

HSV infection is broadly spread all over the world with some patients having severe and/or recurrent HSV infections. Our lab studies human Natural Killer (NK) cells, which are important in innate immune responses to viral infections and tumors. A publication in 2013 by Ornstein et al from our lab studied HSV+ pediatric patients and found some associations between severe infection and defects in NK cytolytic function. PLCG2 haploinsufficient variants found in 2 HSV patients causing PLCγ2 hypophosphorylation, and loss of cytolytic function in NK cells is a novel finding recently published by Alinger et al from our lab in 2023. …

The Role Of Voluntary Descending Control In Enhancing Motor Function Via Transcutaneous Spinal Cord Stimulation, Yoon Kim

McKelvey School of Engineering Graduate Student Theses & Dissertations

Spinal cord injury (SCI) is a life-changing event that causes lasting motor impairments. Transcutaneous spinal cord stimulation (tSCS), a non-invasive form of neuromodulation in which electrodes are placed on the skin and used to stimulate the spinal circuits via an electrical current, has demonstrated positive effects on motor function recovery in individuals who have had SCIs. However, the precise mechanism of how tSCS interacts with voluntary descending drive remains poorly understood. This study aims to investigate the role of voluntary descending control in influencing reflex responses triggered by tSCS.

Electromyography (EMG) recordings were performed in ten unimpaired individuals while they …