Engineering Commons^™

The Impact Of The Mitochondrial Metabolism Of Induced Pluripotent Stem Cells Upon Differentiation, Stefanie T. Shahan

McKelvey School of Engineering Graduate Student Theses & Dissertations

Induced pluripotent stem cells (iPSCs) can be differentiated into any cell type found in the body. The derivation of a stem cell derived β cell (SC-β) capable of responding to glucose by secreting insulin was hugely significant for diabetes research and opened up the possibility of cell replacement therapy to combat this widespread disease (Pagliuca et al. 2014). The optimization of differentiation procedures such as this could improve yield, function, cost, and efficiency of a stem cell-derived product. Current approaches to improve differentiation are primarily focused on signal transduction pathways, while the metabolic state of the cells has received little …

Aerodynamics And Shock Buffet Of A Transonic Airfoil In Ground Effect, Boshun Gao

McKelvey School of Engineering Graduate Student Theses & Dissertations

No abstract provided.

Numerical Simulation Of Enhancement In Co2 Sequestration With Various Water Production Schemes Under Multiple Well Scenarios, Li Chen

McKelvey School of Engineering Graduate Student Theses & Dissertations

CO₂ geological sequestration simultaneously combined with water production from deep saline aquifers can effectively address the challenge faced by the modern energy systems for reducing the CO₂ emissions and water intensity while providing reliable, affordable, and secure energy. However, little attention has been paid to date in the literature on determining the best CO₂ injection strategy for achieving both the optimal water production and the optimal CO₂ space storage capacity while maintaining operational safety. This research first establishes three injection-extraction scenarios based on the typical geological parameters of the Junggar Basin in China to analyze the …

Numerical Determination Of Critical Mach Number Of A Three-Element Airfoil In Unbounded Flow And In Ground Effect, Bowen Hu

McKelvey School of Engineering Graduate Student Theses & Dissertations

The critical Mach number is an important property of airfoils on aerodynamics. When the freestream Mach number exceeds the critical Mach number, shock will appear on the aircraft and cause a huge loss of energy. Lift decreases sharply and drag increases dramatically. We usually hope to increase the critical Mach number and delay the occurrence of shock so that the aircraft can fly with a higher speed and carry more weight.

In this thesis, the main task is to determine the critical Mach number of multi-element airfoil 30P30N in unbounded flow and in ground effect. Commercial software ICEM is employed …

Numerical Drag Prediction Of Nasa Common Research Models Using Different Turbulence Models, Pan Du

McKelvey School of Engineering Graduate Student Theses & Dissertations

The goal of this research is to perform 3D turbulence flow simulations to predict the drag of Wing-body-tail (WBT) and Wing-body-nacelle-Pylon (WBNP) aircraft configurations from NASA Common Research Models. These configurations are also part of the 4th and 6th AIAA Drag Prediction Workshops in which CFD modelers have participated worldwide. The computations are performed using CFD solver ANSYS FLUENT. The compressible Reynolds-Averaged Navier-Stokes (RANS) equations are solved using two turbulence models – the Spalart-Allmaras (SA) and SST k-ω. Drag polar and drag rise curves are obtained by performing computations at different angles of attack at a constant Mach number. Pressure …

Design And Computational Fluid Dynamics Analysis Of An Idealized Modern Wingsuit, Maria E. Ferguson

McKelvey School of Engineering Graduate Student Theses & Dissertations

The aerodynamics of a modern wingsuit has been the subject of very few detailed scientific studies to date. The prevailing design process remains the dangerous “sew and fly” method, in which designs are tested when they are first flown. This study utilizes Computational Fluid Dynamics (CFD) tools to analyze the flow field and aerodynamics of an idealized wingsuit, which is designed using Computer-Aided Design (CAD) modeling. The 3D CAD software Autodesk Inventor is used to create the wingsuit model, which is designed with a Gottingen 228 airfoil cross-section and a relatively large planform of aspect ratio 1.3. The commercial flow …

Uncertainty Quantification Of Turbulence Model Closure Coefficients On Openfoam And Fluent For Mildly Separated Flows, Ike Witte

McKelvey School of Engineering Graduate Student Theses & Dissertations

In this thesis, detailed uncertainty quantification studies focusing on the closure coefficients of eddy-viscosity turbulence models for several flows using two CFD solvers have been performed. Three eddy viscosity turbulence models considered are: the one-equation Spalart-Allmaras (SA) model, the two-equation Shear Stress Transport (SST) k-ω model, and the one-equation Wray-Agarwal (WA) model. OpenFOAM and ANSYS Fluent are used as flow solvers. Uncertainty quantification analyses are performed for subsonic flow over a flat plate, subsonic flow over a backward-facing step, and transonic flow past an axisymmetric bump. In the case of flat plate, coefficients of pressure, lift, drag, and skin friction …

Numerical Study Of The Aerodynamics Of Dlr-F6 Wing-Body In Unbounded Flow Field And In Ground Effect, Ning Deng

McKelvey School of Engineering Graduate Student Theses & Dissertations

The main focus of this thesis is on the simulation of flow past a three-dimensional wing-body configuration (DLR-F6) in ground effect; a complex 3D wing-body configuration in ground effect has never been analyzed in the aerodynamics literature to date. For the purpose of validation of the simulation approach, computations are performed for the DLR-F6 wing-body in unbounded flow and are compared with the experimental data. The commercial CFD solver ANSYS FLUENT is employed for computations. Compressible Reynolds-Averaged Navier-Stokes (RANS) equations in conjunction with Spalart-Allmaras (SA) and - Shear Stress Transport (SST) turbulence models are solved. The validated code is employed …

Computations Of Flow Fields Of An Airfoil And A Wing With Gurney Flap In Ground Effect, Xuan Zhang

McKelvey School of Engineering Graduate Student Theses & Dissertations

High lift devices used in transport aircraft are complex multi-element wings with slats and flaps which are difficult to design and they incur high manufacturing and maintenance costs. Taking all requirements into consideration, for light aircrafts using Gurney Flap may offer a low cost, low maintenance solution for improving the aerodynamic performance of aircraft during take-off and landing. Gurney Flap, first invented by Dan Gurney, is a small tab projecting from the trailing edge of airfoil. Gurney Flap can increase the lift coefficient and decrease the angle of attack for zero lift. However, at low angle of attack, Gurney flap …

Flexible Plasmonic Sensing Substrates And Their Application In Explosive Sensing, Justin Bae, Srikanth Singamaneni

McKelvey School of Engineering Graduate Student Theses & Dissertations

With an increasing use of improvised explosive devices in combat and terrorism, there is an urgent need for novel methods of trace explosive detection that can provide an inexpensive and effective solution. This study focuses on the development of such platform using flexible surface enhanced Raman scattering (SERS) substrates. Gold nanorods(AuNR) functionalized with peptides selective to explosive molecules, trinitrotoluene(TNT) and dinitrotoluene (DNT) were immobilized on various substrates to fabricate a flexible SERS substrate. The peptide conjugated AuNRs can detect TNT and DNT vapors, and the cysteamine conjugated nanorods could detect TNT in aqueous solution down to 100 nM.

Additionally, we …

Investigating Read/Write Aggregation To Exploit Power Reduction Opportunities Using Dual Supply Voltages, Gu Yunfei

McKelvey School of Engineering Graduate Student Theses & Dissertations

Power consumption plays an important role in computer system design today. On-chip memory structures such as multi-level cache make up a significant proportion of total power consumption of CPU or Application-Specific Integrated Circuit (AISC) chip, especially for memory-intensive application, such as floating-point computation and machine learning algorithm. Therefore, there is a clear motivation to reduce power consumption of these memory structures that are mostly consisting of Static Random-Access Memory (SRAM) blocks. In this defense, I will present the framework of a novel dual-supply-voltage scheme that uses separate voltage levels for memory read and write operations. By quantitatively analyzing the cache …

Particle Enrichment In Longitudinal Standing Bulk Acoustic Wave Microfluidics, Mingyang Cui

McKelvey School of Engineering Graduate Student Theses & Dissertations

Separation, isolation, and enrichment of targeted nano- and microparticles are critical to a variety of biomedical applications from clinical research (development of therapeutics and diagnostics) to fundamental investigations that require concentration of specific cells from culture, separation of target species from heterogenous mixtures, or controlled perturbation of cells and microorganisms to determine their response to stimuli. Numerous techniques are available for bench-scale and medical settings; however, these traditional approaches are often labor intensive, time-consuming, costly, and/or require modification of the target. Efficiency and specificity are also lacking. Recently, techniques that exploit the similar scales of microfluidic technologies and the intrinsic …

Cache Power Optimization Using Multiple Voltage Supplies To Exploit Read/Write Asymmetry, Dengxue Yan

McKelvey School of Engineering Graduate Student Theses & Dissertations

Power consumption becomes more and more critical in computer systems nowadays. Most of the previous work has been focusing on general-purpose computational core, but optimization techniques for conventional CPU core has reached a limit. Our experimental results show that read operations in SRAM can be performed at a lower supply with much reduced power consumption compared to write operations. Based on this observation and the fact that cache, consisting mostly of SRAM, often occupies significant on-chip area of the CPU and consumes a huge portion of the CPU power, we propose a new method to reduce the power consumption of …

Using Pet/Mri To Assess Hepatic Radioembolization Of Yttrium-90 Microspheres, Nichole Millward Maughan

McKelvey School of Engineering Graduate Student Theses & Dissertations

Radioembolization of yttrium-90 (Y-90) microspheres is used to treat primary and secondary cancers in the liver. Though this therapy has existed for decades, the treatment is not well optimized from treatment planning to post-procedural assessment. Recently, there has been a surge to utilize the small positron yield from the radioactive decay of Y-90 for post-radioembolization positron emission tomography (PET) imaging of the microsphere activity distribution. These images provide promise for dosimetry assessment, identifying extrahepatic uptake and possible under-dosed lesions that may benefit from subsequent therapy. However, due to the low positron statistics and high flux of Bremsstrahlung radiation, PET imaging …

Pet/Mr Imaging Of Hypoxic Atherosclerotic Plaque Using 64cu-Atsm, Xingyu Nie

McKelvey School of Engineering Graduate Student Theses & Dissertations

ABSTRACT OF THE DISSERTATION

PET/MR Imaging of Hypoxic Atherosclerotic Plaque Using 64Cu-ATSM

by

Xingyu Nie

Doctor of Philosophy in Biomedical Engineering

Washington University in St. Louis, 2017

Professor Pamela K. Woodard, Chair

Professor Suzanne Lapi, Co-Chair

It is important to accurately identify the factors involved in the progression of atherosclerosis because advanced atherosclerotic lesions are prone to rupture, leading to disability or death. Hypoxic areas have been known to be present in human atherosclerotic lesions, and lesion progression is associated with the formation of lipid-loaded macrophages and increased local inflammation which are potential major factors in the formation of vulnerable …

Characterizing Structure, Properties, And Deformation In Metallic Glasses And Olivine Using Instrumented Nanoindentation, Kelly Kranjc

McKelvey School of Engineering Graduate Student Theses & Dissertations

Micro- and nanomechanical testing can provide significant insight about the structure, properties, and behavior of materials. These techniques are nondestructive, require only limited amounts of material, and have been known to detect a brittle-to-ductile transition in mechanical behavior due to a size effect. This work utilizes this type of testing to explore fundamental questions about the structure, properties, and behavior of two disparate material systems: metallic glasses and olivine.

Metallic glasses are metallic alloys devoid of any long-range order. Their unique atomic structure imbues them with properties such as a high elastic strain limit, near-theoretical strengths, and the ability to …

The Effect Of Diffusive Transport On Mineral Carbonation In Geologic Carbon Sequestration, Wei Xiong

McKelvey School of Engineering Graduate Student Theses & Dissertations

Geologic carbon sequestration (GCS) is an effective method to mitigate environmental problems due to excessive anthropogenic CO2 emissions. It involves injecting supercritical CO2 into deep geologic formations in which CO2 will ultimately be converted to solid carbonate minerals. Basalt is a promising host rock that is rich in the divalent cations Ca, Mg and Fe that are important for mineral trapping of CO2. Fractures and pores in basalt reservoirs provide substantial surface area for geochemical reactions during carbon sequestration. The transport in fractures and pores is controlled by diffusion. The coupling of diffusive transport and geochemical reactions leads to carbonate …

Uncertainty Quantification Of Wall-Modeled Large Eddy Simulation (Wmles) Model In Openfoam, Zuoxian Hou

McKelvey School of Engineering Graduate Student Theses & Dissertations

In this thesis, a non-intrusive uncertainty quantification (UQ) method is used to improve the accuracy of a wall-modeled large eddy simulation (WMLES) model. Detailed UQ studies focusing on the closure coefficients of two LES models are performed. A non-intrusive polynomial chaos model is used to evaluate output sensitivities and uncertainties in the entire flow domain. The proposed UQ method allows for the investigation of specific flow features and phenomena within the domain. The results of the UQ analyses are then used to identify which turbulence model closure coefficients most influence the flow features of interest. Sobol indices of closure coefficients …

Sub 2 Nm Particle Characterization In Systems With Aerosol Formation And Growth, Yang Wang

McKelvey School of Engineering Graduate Student Theses & Dissertations

Aerosol science and technology enable continual advances in material synthesis and atmospheric pollutant control. Among these advances, one important frontier is characterizing the initial stages of particle formation by real time measurement of particles below 2 nm in size. Sub 2 nm particles play important roles by acting as seeds for particle growth, ultimately determining the final properties of the generated particles. Tailoring nanoparticle properties requires a thorough understanding and precise control of the particle formation processes, which in turn requires characterizing nanoparticle formation from the initial stages. The knowledge on particle formation in early stages can also be applied …

The Electrophysiology Of Resting State Fmri Networks, Carl David Hacker

McKelvey School of Engineering Graduate Student Theses & Dissertations

Traditional research in neuroscience has studied the topography of specific brain functions largely by presenting stimuli or imposing tasks and measuring evoked brain activity. This paradigm has dominated neuroscience for 50 years. Recently, investigations of brain activity in the resting state, most frequently using functional magnetic resonance imaging (fMRI), have revealed spontaneous correlations within widely distributed brain regions known as resting state networks (RSNs). Variability in RSNs across individuals has found to systematically relate to numerous diseases as well as differences in cognitive performance within specific domains. However, the relationship between spontaneous fMRI activity and the underlying neurophysiology is not …

Development And Applications Of Novel Fluorescent Molecular Probe Strategies, Dolonchampa Maji

McKelvey School of Engineering Graduate Student Theses & Dissertations

Optical imaging and spectroscopy technologies offer the ability to provide structural and functional information in a fast, low-cost, ionizing radiation free, highly sensitive and high throughput fashion. The diverse contrast mechanisms and complementary imaging platforms form the foundation for the application of optical imaging in pre-clinical studies of pathophysiological development as well as direct clinical application as a tool for diagnosis and therapy. Fluorescence imaging techniques have been one of the most rapidly adopted methods in biology and biomedicine. Visualization of biological processes and pathologic conditions at the cellular and tissue levels largely relies on the use of exogenous fluorophores …

Underwater Celestial Navigation Using The Polarization Of Light Fields, Samuel Bear Powell

McKelvey School of Engineering Graduate Student Theses & Dissertations

Global-scale underwater navigation presents challenges that modern technology has not solved. Current technologies drift and accumulate errors over time (inertial measurement), are accurate but short-distance (acoustic), or do not sufficiently penetrate the air-water interface (radio and GPS). To address these issues, I have developed a new mode of underwater navigation based on the passive observation of patterns in the polarization of in-water light. These patterns can be used to infer the sun__s relative position, which enables the use of celestial navigation in the underwater environment. I have developed an underwater polarization video camera based on a bio-inspired polarization image sensor …

Measuring Molecular Orientation And Rotational Mobility Using A Tri-Spot Point Spread Function, Oumeng Zhang

McKelvey School of Engineering Graduate Student Theses & Dissertations

Single molecules have become a powerful tool for biophysicists since they were first optically detected 28 years ago. Understanding molecular orientation can not only improve the accuracy of single-molecule localization, but it can also provide insight into biochemical behaviors at the nanoscale. In this thesis, I present a method to measure the molecular orientation and rotational mobility of single-molecule emitters by designing and implementing a tri-spot point spread function. The point spread function is designed so that it is capable of measuring all degrees of freedom related to molecular orientation and rotational mobility. Its design is optimized by maximizing the …

Conjoint Audiogram Estimation Via Gaussian Process Classification, James Dilorenzo

McKelvey School of Engineering Graduate Student Theses & Dissertations

In traditional audiometry, a clinician seeks to estimate her patient’s auditory response through the sequential delivery of various individual tests. These tests are treated as independent and correlation is assessed after each individual test has been completed, resulting in a diagnosis. Treating tests as independent impedes both accuracy and efficiency by ignoring correlations in conditions known to influence physiological response, for instance age, genetics, and exposure to noise. This thesis advances the existing framework for audiometry via Gaussian Processes by allowing for the estimation of audiogram thresholds for both ears simultaneously. The resulting model estimates both correlated and uncorrelated right- …

Assessing Dprestin & Nadc1 (Indy) Interaction On Calcium Oxalate Crystal Formation In A Drosophila Model Of Kidney Stones, Jessica Lin

Undergraduate Research Symposium Posters

Calcium oxalate (CaOx) accounts for >70%of kidney stones, yet why CaOx stones form is poorly understood. While several factors contribute to the stone aggregation and growth, elucidating the roles of oxalate transporters can help demystify this phenomenon. Using a Drosophila model to study the formation and inhibition of CaOx crystals in the fly Malpighian tubule (MT), oxalate transport via dPrestin—the fly Slc26a6 Cl^-/Ox^2- exchanger was studied using both electrophysiology and MT dissection with CaOx birefringence assays. Here, the fly model suffices as it recapitulates renal oxalate excretion. Additionally, the mammalian dicarboxylate transporter NaDC1 (Indy in Drosophila) …

Activity Preservation Of Plasmonic Biosensors With A Metal-Organic Framework, Lu Wang

McKelvey School of Engineering Graduate Student Theses & Dissertations

Antibody-antigen recognition enables antibody-conjugated nanostructures to serve as plasmonic biosensors with tunable specificity. However due to the instability of antibodies, these biosensors are susceptible to changes in the environment such as heat and aridity, leading to constraints on the transportation and handling of these sensors. Here we establish a method using a metal-organic framework crystal to preserve biosensor activity under severe environmental conditions, including exposure to high temperatures, an organic solvent and a proteolytic agent. After zeolitic imidazolate framework-8 (ZIF-8) crystals formed for 12 hours on a biosensor of gold nanorods conjugated with a model antibody, rabbit IgG, 80% of …

Towards Clinical Photoacoustic Imaging: Developing Next-Generation Endoscopy Systems And Exploring New Contrast Agents, Chiye Li

McKelvey School of Engineering Graduate Student Theses & Dissertations

Photoacoustic imaging holds great clinical promise because it achieves high-resolution tomographic imaging at depths. Moreover, its strong spectroscopic imaging capability provides a wealth of molecular and functional information based on. Still, despite recent advances, existing photoacoustic systems cannot be readily applied in the clinical environment. This dissertation aims to push the frontier of clinical photoacoustic imaging from both technological and applicational perspectives.

The first part of this dissertation describes the development of photoacoustic endoscopy (PAE) systems for imaging human Barrett's esophagus and studying preterm birth. We have developed optical resolution-PAE, which significantly improved lateral resolutions, laparoscopic-PAE, which can guide minimally-invasive …

On Control Systems Of The Brain: A Study Of Their Connections, Activations, And Interactions, Haoxin Sun

McKelvey School of Engineering Graduate Student Theses & Dissertations

Implementation of daily functions in humans crucially relies on both the bottom-up moment-to- moment processing of relevant input and output information as well as the top-down controls that instantiate and regulate goal-directed strategies. The current dissertation focuses on different systems of brain regions related to task control. We are interested in investigating, in detail, some of the basic activity patterns that different control systems carry during simple tasks, and how differences in activity patterns may shed new insight onto the distinctions among the systems' functional roles. In addition, carefully coordinated interactions between brain regions specialized for control-related activity and regions …

Developing High Purity Embryonic Stem Cell-Derived V2a Interneurons For In Vitro Investigation And Transplantation Following Spinal Cord Injury, Nisha Iyer

McKelvey School of Engineering Graduate Student Theses & Dissertations

Functional recovery following spinal cord injury has been attributed to plasticity in local interneuron populations, which are able to create novel circuits that bypass the inhibitory lesion to activate pre-existing motor pathways. Cell replacement strategies and growth factor delivery platforms often attempt to enhance these natural mechanisms of regeneration. The work of this thesis sought to overcome the major obstacle to manipulating specific interneurons for therapy: an inability to obtain large, enriched interneuron subpopulations for drug screening and transplantation. We focused on the generation of V2a interneurons, which normally coordinate a wide range of locomotor tasks in both the spinal …

Applications Of Aerosol Technologies In The Silicon Industry, Miguel Vazquez Pufleau

McKelvey School of Engineering Graduate Student Theses & Dissertations

In this dissertation, the focus was on two unit operations that have the potential to significantly lower the cost and energy required for refining silicon. First, the removal of carbon from silicon kerf (sawing dust from wafering) was examined to enable its recycling. Second, silane pyrolysis was studied to better understand the dynamics of the initial stages of silicon aerosol formation and growth.