Engineering Commons^™

Constructing And Analyzing Neural Network Dynamics For Information Objectives And Working Memory, Elham Ghazizadeh Ahsaei

McKelvey School of Engineering Graduate Student Theses & Dissertations

Creation of quantitative models of neural functions and discovery of underlying principles of how neural circuits learn and compute are long-standing challenges in the field of neuroscience. In this work, we blend ideas from computational neuroscience, information and control theories with machine learning to shed light on how certain key functions are encoded through the dynamics of neural circuits. In this regard, we pursue the ‘top-down’ modeling approach of engineering neuroscience to relate brain functions to basic generative dynamical mechanisms. Our approach encapsulates two distinct paradigms in which ‘function’ is understood. In the first part of this research, we explore …

Neural Coding And Organization Principles In The Drosophila Olfactory System, Haoyang Rong

McKelvey School of Engineering Graduate Student Theses & Dissertations

Sensory systems receive and process external stimuli to allow an organism to perceive and react to the environment. How is sensory information subsequently represented, transformed, and interpreted in the neural system? In this dissertation, I have investigated this fundamental question using the fruit fly (Drosophila melanogaster) olfactory system.Chemical cues are transduced into neural signals in the insect antenna by the olfactory receptor neurons (ORNs). The ORNs send their axons to the antennal lobe (AL), with each ORN type innervating a specific neuropil (glomerulus), where they synapse onto excitatory and inhibitory projection neurons (ePNs and iPNs). The ePNs project their axons …

Focused Ultrasound-Mediated Drug Delivery To The Brainstem, Dezhuang Ye

McKelvey School of Engineering Graduate Student Theses & Dissertations

Brainstem gliomas are tumors that occur in the brainstem, the brain region that connects the brain to the spinal cord and controls vital body functions. The critical anatomic location of the brainstem precludes surgical intervention and limits the use of invasive therapeutic techniques. Moreover, the frequently intact blood-brain barrier (BBB) of most brainstem gliomas prevents therapeutic agents from reaching the diseased site. The currently available techniques for brain drug delivery are either invasive (e.g., convection-enhanced delivery) or lack targeting to the diseased site (e.g., intranasal brain drug delivery). Novel techniques that can noninvasively overcome the BBB are critically needed for …

Holistic Control For Cyber-Physical Systems, Yehan Ma

McKelvey School of Engineering Graduate Student Theses & Dissertations

The Industrial Internet of Things (IIoT) are transforming industries through emerging technologies such as wireless networks, edge computing, and machine learning. However, IIoT technologies are not ready for control systems for industrial automation that demands control performance of physical processes, resiliency to both cyber and physical disturbances, and energy efficiency. To meet the challenges of IIoT-driven control, we propose holistic control as a cyber-physical system (CPS) approach to next-generation industrial automation systems. In contrast to traditional industrial automation systems where computing, communication, and control are managed in isolation, holistic control orchestrates the management of cyber platforms (networks and computing platforms) …

Differentiating Human Embryonic Stem Cells In Micropatterns To Study Cell Fate Specification And Morphogenetic Events During Gastrulation, Kyaw Thu Minn

McKelvey School of Engineering Graduate Student Theses & Dissertations

During mammalian embryogenesis, the first major lineage segregation occurs when embryonic epiblast, and extraembryonic trophectoderm and hypoblast arise in the blastocyst. In the next fundamental and conserved phase of animal embryogenesis known as gastrulation, extraembryonic cells provide signals to epiblast to instruct embryonic patterning, and epiblast gives rise to germ layers ectoderm, mesoderm, and endoderm, that will establish all embryonic tissues. Proper specification and morphogenesis of germ layers during gastrulation is vital for correct embryonic development. Due to ethical and legal restrictions limiting human embryo studies, human gastrulation is poorly understood. Our knowledge of human gastrulation has largely been derived …

Theory, Design And Implementation Of Energy-Efficient Biotelemetry Using Ultrasound Imaging, Sri Harsha Kondapalli

McKelvey School of Engineering Graduate Student Theses & Dissertations

This dissertation investigates the fundamental limits of energy dissipation in establishing a communication link with implantable medical devices using ultrasound imaging-based biotelemetry.

Ultrasound imaging technology has undergone a revolution during the last decade due to two primary innovations: advances in ultrasonic transducers that can operate over a broad range of frequencies and progresses in high-speed, high-resolution analog-to-digital converters and signal processors. Existing clinical and FDA approved bench-top ultrasound systems cangenerate real-time high-resolution images at frame rates as high as 10000 frames per second. On the other end of the spectrum, portable and hand-held ultrasound systems can generate high-speed real-time scans, …

Liposomal Delivery Of Remdesivir For Localized And Targeted Treatment Of Covid-19, Anupama Melam

McKelvey School of Engineering Graduate Student Theses & Dissertations

Liposomal delivery of Remdesivir for localized and targeted treatment of COVID-19

COVID-19 is a serious, and in many cases lethal, disease that is caused by infection of the upper respiratory tract by the novel betacoronavirus, SARS-Cov-2 virus. This disease has a very high mortality rate and has affected the world in a global pandemic. SARS-Cov-2 binds to the ACE2 receptor via the receptor-binding domain (RBD) in the S protein. After this, the virus fuses with the cell membrane by the formation of a six-helix bundle. Thus, the S protein plays a major role in ensuring that the virus attaches to …

Single‐Molecule 3d Orientation Imaging Reveals Nanoscale Compositional Heterogeneity In Lipid Membranes, Jin Lu, Hesam Mazidi, Tianben Ding, Oumeng Zhang, Matthew D. Lew

Electrical & Systems Engineering Publications and Presentations

In soft matter, thermal energy causes molecules to continuously translate and rotate, even in crowded environments, thereby impacting the spatial organization and function of most molecular assemblies, such as lipid membranes. Directly measuring the orientation and spatial organization of large collections (>3000 molecules μm⁻²) of single molecules with nanoscale resolution remains elusive. In this paper, we utilize SMOLM, single‐molecule orientation localization microscopy, to directly measure the orientation spectra (3D orientation plus “wobble”) of lipophilic probes transiently bound to lipid membranes, revealing that Nile red's (NR) orientation spectra are extremely sensitive to membrane chemical composition. SMOLM images resolve …

Prototype Instrument Development For Measuring Directionality Of Aerosol Light Scattering, Esther K. Monroe

McKelvey School of Engineering Graduate Student Theses & Dissertations

Investigation of aerosol interactions with electromagnetic waves provides insights into the scattering particles. Aerosol phase function, an angular distribution of scattered light, is a value required to calculate parameters used in direct radiative forcing (DRF) models in the atmosphere. Currently no direct measurement of phase function is available hence it is estimated from ground observations such as backscatter fraction b and subsequently relating the parameters via Henyey-Greenstein (HG) approximation. This method has shown to introduce errors in radiation transfer models. HG phase function, in particular, does not account for particle microphysical properties such as shape and refractive index. Given the …

Advanced Materials For Air Pollutants Removal In A Combustion System, Sungyoon Jung

McKelvey School of Engineering Graduate Student Theses & Dissertations

Air pollutants directly or indirectly impact human health and the environment. Large quantities of CO2, volatile organic compounds (VOCs), and particulate matter are emitted from combustion systems, and cause climate change, smog formation, and pose serious health risks. The increasing demand for the remediation of air pollutants at the source has drawn much attention to the use of advanced materials due to their high reactivities and special properties. In order to achieve the successful application of advanced materials for the remediation of problematic emissions, three aspects, (1) synthesis method, (2) characterization of materials’ structural properties, and (3) evaluation of materials’ …

Growth Of Small Particles In Nonequilibrium Plasmas, Necip Berker Üner

McKelvey School of Engineering Graduate Student Theses & Dissertations

Nonequilibrium plasma (NEP) is an extraordinary environment for material synthesis. NEP is comprised of hot electrons with temperatures greater than 10000 K and of cold ions and neutrals that are usually at few hundred kelvins above room temperature. Due to this large difference in species’ temperatures, the assumption of local thermal equilibrium does not hold in NEP. Therefore, NEP can act as a unique processor of mass, and it can transform materials along pathways that are not accessible by methods wherein local thermal equilibrium is valid. For decades, NEPs have been employed in the semiconductor industry to manufacture many thin …

Convex Relaxations For Particle-Gradient Flow With Applications In Super-Resolution Single-Molecule Localization Microscopy, Hesam Mazidisharfabadi

McKelvey School of Engineering Graduate Student Theses & Dissertations

Single-molecule localization microscopy (SMLM) techniques have become advanced bioanalytical tools by quantifying the positions and orientations of molecules in space and time at the nanoscale. With the noisy and heterogeneous nature of SMLM datasets in mind, we discuss leveraging particle-gradient flow 1) for quantifying the accuracy of localization algorithms with and without ground truth and 2) as a basis for novel, model-driven localization algorithms with empirically robust performance. Using experimental data, we demonstrate that overlapping images of molecules, a typical consequence of densely packed biological structures, cause biases in position estimates and reconstruction artifacts. To minimize such biases, we develop …

Aging Effects On Arterial Mechanics And Matrix Remodeling, Jie Hawes

McKelvey School of Engineering Graduate Student Theses & Dissertations

Large elastic arteries are a composite structure composed of cells and extracellular matrix proteins. Passive arterial mechanical behavior is determined by the composition of extracellular matrix proteins, in particular elastin and collagen. Elastin provides reversible elasticity to the large elastic arteries during cyclic loading and dampens the pulsatile flow from the left ventricle, reducing the workload on the heart and protecting the end organs. Disorganization and insufficiency of elastin alters the passive mechanical behavior of the large arteries. The arterial wall responds to changes in elastin organization or amount through matrix remodeling. Aging causes elastin fragmentation and degradation which changes …

Microrna Gene Expression States Underlying Individual Variation In Aging And Lifespan In Isogenic C. Elegans, Holly Kinser

McKelvey School of Engineering Graduate Student Theses & Dissertations

Average lifespan differs greatly between species, but lifespan among same-species individuals is also highly variable. While much effort has been devoted to uncovering longevity-associated traits and lifespan-extending perturbations in humans and model organisms, how differences in lifespan arise between individuals is unknown. Studies of human identical twins demonstrate that surprisingly little of the variation in lifespan between individuals can be explained by genetics and shared environment. Furthermore, even genetically identical C. elegans reared in highly homogeneous environments display a degree of variability in lifespan similar to that of outbred human populations. Thus, longevity must be determined at least in part …

Structural Organization And Chemical Activity Revealed By New Developments In Single-Molecule Fluorescence And Orientation Imaging, Tianben Ding

McKelvey School of Engineering Graduate Student Theses & Dissertations

Single-molecule (SM) fluorescence and its localization are important and versatile tools for understanding and quantifying dynamical nanoscale behavior of nanoparticles and biological systems. By actively controlling the concentration of fluorescent molecules and precisely localizing individual single molecules, it is possible to overcome the classical diffraction limit and achieve 'super-resolution' with image resolution on the order of 10 nanometers.

Single molecules also can be considered as nanoscale sensors since their fluorescence changes in response to their local nanoenvironment. This dissertation discusses extending this SM approach to resolve heterogeneity and dynamics of nanoscale materials and biophysical structures by using positions and orientations …

Domain Specific Computing In Tightly-Coupled Heterogeneous Systems, Anthony Michael Cabrera

McKelvey School of Engineering Graduate Student Theses & Dissertations

Over the past several decades, researchers and programmers across many disciplines have relied on Moores law and Dennard scaling for increases in compute capability in modern processors. However, recent data suggest that the number of transistors per square inch on integrated circuits is losing pace with Moores laws projection due to the breakdown of Dennard scaling at smaller semiconductor process nodes. This has signaled the beginning of a new “golden age in computer architecture” in which the paradigm will be shifted from improving traditional processor performance for general tasks to architecting hardware that executes a class of applications in a …

New Modeling Approaches For The Prediction Of Combustion Pollutants, Phillip R. Johnson

McKelvey School of Engineering Graduate Student Theses & Dissertations

Combustion processes are ubiquitous to human technological development and provide many benefits such as large-scale power generation for electricity and transportation along with residential and commercial heating for manufacturing, cooking, and warmth. However, these various processes can also have harmful effects on human health and the environment via emission of CO2 and other pollutants such as NOx and particulate matter (PM; often in the form of soot). For these reasons, there is a continued need for controlling, improving, and optimizing combustion processes. Modeling of these processes provides powerful insights into system-level dynamics and their control. Due to the size and …

Particle Studies In The Lab And Pilot-Scale Coal Combustion Systems, Dishant Khatri

McKelvey School of Engineering Graduate Student Theses & Dissertations

In the past century, coal contributed more to the global electricity supply than any other source. Currently, it alone accounts for over 35% of the global electricity supply. Though coal is globally well-distributed and can provide cheap, stable, and reliable energy on demand, it emits a large amount of carbon dioxide—a greenhouse gas responsible for global warming. Additionally, it is a major source of particulate matter (PM) pollution. Thus, in recent years, to reduce the impact of coal on climate, several policies have been introduced to phase out coal. However, replacing coal with intermittent renewables has led to a reduction …

A Thesis On The Interactions Between Lead Pipe Scales And Dissolved Silica From The Addition Of Sodium Silicate As A Corrosion Inhibitor, Ziqi Wang

McKelvey School of Engineering Graduate Student Theses & Dissertations

Ingestion of lead-contaminated drinking water is one of the major pathways for human exposure to lead. Addition of sodium silicate can potentially control lead release from lead service lines (LSLs) to the water that they convey, but the mechanism of silica uptake and corrosion control have not been reported. Knowledge of variables which affect the uptake of dissolved silica and the consumption rate of added sodium silicate by scales of corrosion products that are present on lead service lines will be useful to water utilities and distribution systems. This study investigated the effects of pH, initial silica concentration and mass …

First-Principles Investigation Of Doping And Alloying Of Β-Ga2o3, Ben Tattersfield

McKelvey School of Engineering Graduate Student Theses & Dissertations

β-Ga₂O₃ is an emergent semiconductor for power electronics applications. It has a wide band gap of 4.8 eV and is transparent on the whole spectrum of visible light up to deep ultraviolet. It has a high Baliga figure of merit (BFOM) — a weighted numerical combination of the dielectric constant, charge carrier mobility, and critical breakdown field —, which is commonly used for a quantitative comparison of semiconductors for high-current operation and power switching applications. β-Ga₂O₃ can be grown as thin films or as large single crystals by melt growth-techniques, which is …

Large Face Shield, Michael Stieven, Dylan Huddleston, Timothy Bragg

Washington University / UMSL Mechanical Engineering Design Project JME 4110

The large face shield is designed to help stop the spread of COVID-19 Coronavirus in occupational environments where close contact is necessary.

Data Processing Electronics For An Ultra-Fast Single-Photon Counting Camera, Jackson Hyde

McKelvey School of Engineering Graduate Student Theses & Dissertations

Localizing photon arrivals with high spatial (megapixel) and temporal (sub-nanosecond) resolution would be transformative for a number of applications, including single-molecule super-resolution fluorescence microscopy. Here, the Data Processing Field Programmable Gate Array (FPGA) is developed as an ultra-fast computational platform built on an FPGA for a microchannel plate (MCP)-photomultiplier tube (PMT) based single-photon counting camera. Each photon is converted by the MCP-PMT into an electron cloud that generates current pulses across a 50×50 cross-strip anode. The Data Processing FPGA executes a massively parallel center-of-gravity coordinate determination algorithm on the digitized current pulses to determine a 2D position and time of …

Investigating Single Precision Floating General Matrix Multiply In Heterogeneous Hardware, Steven Harris

McKelvey School of Engineering Graduate Student Theses & Dissertations

The fundamental operation of matrix multiplication is ubiquitous across a myriad of disciplines. Yet, the identification of new optimizations for matrix multiplication remains relevant for emerging hardware architectures and heterogeneous systems. Frameworks such as OpenCL enable computation orchestration on existing systems, and its availability using the Intel High Level Synthesis compiler allows users to architect new designs for reconfigurable hardware using C/C++. Using the HARPv2 as a vehicle for exploration, we investigate the utility of several of the most notable matrix multiplication optimizations to better understand the performance portability of OpenCL and the implications for such optimizations on this and …

Coupled Inflow And Structural Dynamics Of Rotors With Time Delays And Adjoint Variables, Cory Andrew Seidel

McKelvey School of Engineering Graduate Student Theses & Dissertations

In this work, the finite-state models of Morillo-Duffy and Fei (including the Adjoint Theorem) are expanded to calculate the coupled inflow and rotor dynamics of a multi-rotor systems. Because the Adjoint Theorem involves coupling of rotor and inflow states with adjoint rotor states (including pure time delays in both types of variables), the resultant coupled dynamics experiences characteristics heretofore not studied in a dynamic system. It is the purpose of this work to study these new and interesting dynamic behaviors that can occur in the physically meaningful context of a coaxial rotor. The work is also interested in how this …

Power Delivery Network As A Physically Unclonable Function, Patrick Naughton, Robert Esswein

Electrical and Systems Engineering Capstone Design Projects

Abstract— Physically unclonable functions leverage process variation in the manufacture of silicon chips and circuit boards to map inputs to outputs in an irreversible and unpredictable but consistent manner. They have many applications as security primitives: they can serve as truly random number generators, create secret keys, and fingerprint specific chips. These primitive functions can then be used to secure confidential information and regulate access to private resources. Current approaches tend to utilize variation in the production of silicon dies as the source of variability in their function’s output. We present a PUF that leverages variation in the entire circuit …

Influence Of Separator Surface Charge On The Nucleation And Penetration Dynamics Of Metal Electrodes In Concentrated Electrolytes, Sikuang Wang

McKelvey School of Engineering Graduate Student Theses & Dissertations

No abstract provided.

Cfd Evaluation Of Blood Flow In An Improved Blalock-Taussig Shunt Using Patient Specific Geometries, Zhenghao Lin

McKelvey School of Engineering Graduate Student Theses & Dissertations

Blalock-Taussig (BT) Shunt is a palliative surgical procedure used during a Norwood surgery on a newborn baby suffering from cyanotic heart defects. The BT Shunt can increase blood flow in patients’ pulmonary artery which can ease the “Blue Baby Syndrome.” Currently used BT Shunts do not produce a balanced flow distribution to the pulmonary arteries (PAs) which can cause high wall shear stress (WSS) and blood flow separation resulting in blood clots. A modified BT Shunt was designed to partially solve this problem. In our previous work [1], the modified BT Shunt was shown by numerical simulations to have the …

Ultrasound Guided Diffuse Optical Tomography For Breast Cancer Diagnosis: Algorithm Development, K M Shihab Uddin

McKelvey School of Engineering Graduate Student Theses & Dissertations

According to National Breast Cancer Society, one in every eight women in United States is diagnosed with breast cancer in her lifetime. American Cancer Society recommends a semi-annual breast-cancer screening for every woman which can be heavily facilitated by the availability of low-cost, non-invasive diagnostic method with good sensitivity and penetration depth. Ultrasound (US) guided Diffuse Optical Tomography (US-guided DOT) has been explored as a breast-cancer diagnostic and screening tool over the past two decades. It has demonstrated a great potential for breast-cancer diagnosis, treatment monitoring and chemotherapy-response prediction. In this imaging method, optical measurements of four different wavelengths are …

Blood Flow Simulation Of Particle Trapping In Models Of Arterial Bifurcations, Qihang Xu

McKelvey School of Engineering Graduate Student Theses & Dissertations

This thesis describes the particle trapping mechanism in blood flow in different arterial bifurcation models. For validation of CFD calculations, a T-junction model and a Y-junction model are analyzed. In both the models, there is one inlet pipe with two outlet pipes creating a symmetric bifurcation at some angle from the centerline of the inlet pipe. Naiver-Stokes (RANS) equations are solved for single phase laminar flow using the commercial CFD software ANSYS Fluent. After validation, Eulerian simulations are performed by using the Discrete Phase Model (DPM) for two-phase flow with particles injected in different bifurcation models with bifurcation angle of …

Development And Application Of Elliptic Blending Lag K-Omega Sst Standard And Wall-Distance-Free Turbulence Model, Wenjie Shang

McKelvey School of Engineering Graduate Student Theses & Dissertations

In recent decades, Computational Fluid Dynamics (CFD) has become the most widely used technology to understand the fundamental complex fluid dynamics of turbulent flows as well as for modeling of turbulent flows in industrial applications. In industrial applications, the widely used methodology is to solve Reynolds-Average Navier-Stokes Equations (RANS) equations in conjunction with a turbulence model since it strikes a balance between accuracy and computational cost compared to other high fidelity approaches namely the Large Eddy Simulation (LES) and Direct Numerical Simulation (DNS), There are a large number of turbulence models proposed in past five decades, majority of them are …