Engineering Commons^™

Upper Regime Bedform Geometries And Types As A Function Of Sediment Supply And Grain Size, Sydney Sanders

Theses and Dissertations

Most research on fluvial bedforms focuses on the study of dunes (lower regime), and much less is known on upper regime bedforms. Studying upper regime bedforms, the conditions in which they form and how the geometry changes with flow and sediment properties is necessary for interpreting the stratigraphic record, estimate flow resistance and reconstruct flow characteristics from observed geometries. Here I present results of laboratory experiments designed to investigate the role of suspended bed material and sediment grain size on upper regime bedforms. Experiments were performed in open channel flow mode in a sediment-feed flume with a 0.19 m wide, …

Engineering And Optimization Of An Aav Based Viral Vector To Limit The In-Vitro Expression Of Sars-Cov-2 Spike-Protein, Ronald Anderson Smithwick

Theses and Dissertations

Severe Acute Respiratory Syndrome Corona Virus-2, also known as SARS-CoV-2, is a newly emerged respiratory viral pathogen. The outbreak of SARS-CoV-2 started in Wuhan, China, in late 2019 and rapidly transformed into a pandemic. Several vaccines have been developed and are available to the public on an unprecedented timeline, protecting individuals from a severe infection and saving precious lives. However, none of the vaccines can provide a sterile immunity, and the SARS-CoV-2 transmission cycle continues. Additionally, because of the mutation-prone RNA genome and immunological selection pressure, SARS-CoV-2 is rapidly mutating, especially the Spike(S) protein, and new viral strains are arising …

First-Principles Based Heterogeneous Catalyst Design For Energy Conversion And Plastics Upcycling Processes, Kyung-Eun You

Theses and Dissertations

Replacing scarce and expensive Pt-group metals (Pt, Pd, Ir, Rh, and Ru) commonly used in heterogeneous catalysis with earth-abundant and inexpensive materials is an important challenge to achieve sustainability

The main focus of the first project is to develop highly selective non-precious metal catalysts for the hydrodeoxygenation (HDO) of biomass-derived polyols and we chose to examine the HDO of glycerol and its deoxygenated reaction products (1,2- and 1,3- propanediol) over Cu modified Mo₂C (Cu/Mo₂C) catalysts. In this study, we combined experimental and density functional theory (DFT) results to reveal that the Cu modifier can significantly reduce …

Manufacturing Process Considerations When Transitioning From Thermoset To Thermoplastic Composite Material For Urban Air Mobility Propellers, Samuel Leonard Jones Iii

Theses and Dissertations

Aerospace manufacturing has seen continually increased use of carbon fiber reinforced polymers in aircraft structures. The favorable strength to weight ratios, as well as the increased resistance to fatigue and corrosion, compared to metallic structures, provide a common argument for further research and development of composite airframes. Two main classes of carbon fiber reinforced polymers can be distinguished, thermosetting polymers and thermoplastic polymers. Thermoset polymers have been relied on for decades for the ability to reliably produce strong laminates for aircraft structures. By comparison thermoplastic polymers experience less comparable utilization on primary structures despite boasting similar or greater performance capabilities …

Fundamentals Of Adsorption And Large Scale Pressure Swing Adsorption (Psa) Process Design, Huan Jiang

Theses and Dissertations

This work focused on both fundamental of adsorption and large-scale PSA design. Chapter 1 and 2 addressed the analysis of conditions for formation of adsorption azeotropes in binary systems. Chapter 1 theoretically assessed the necessary and sufficient conditions for the formation of an adsorption azeotrope in a binary gas mixture when this mixture exhibits either intersecting or non-intersecting single gas isotherms. Chapter 2 confirmed theoretically whether adsorption azeotropes can form in a binary mixture at a pressure below the intersection pressure of the corresponding single gas isotherms. Analytical expressions derived for both general and dual thermodynamically consistent process Langmuir (DPL) …

Classification Of Acoustic Emission Data Into Load Steps Using An Artificial Neural Network, Allen Ross

Theses and Dissertations

The average age of bridges in South Carolina is approaching 40 years, very close to the 50-year service life. Almost 11% of the bridges in South Carolina are rated as structurally deficient, greater than the national average of 7.5% (South 2021). Health monitoring is the concept that in-situ sensors can continuously monitor civil structures and send real time signals of damage. This process allows for automation and could save time and money on the inspection and load rating of bridges. Health monitoring requires sensors that provide uninterrupted data without sacrificing the functionality of the bridge. A prime candidate for this …

Interrogating The Role Of Ing4 In Hematopoietic Stem Cells And Cancer, Zanshé Thompson

Theses and Dissertations

We recently identified the tumor suppressor, Ing4, as a critical regulator of hematopoietic stem cell (HSC) homeostasis. The mis-regulation of Ing4 in human cancers has also been shown to lend malignant cells specific advantages that support carcinogenesis and tumor progression. This activity is, in part, due to Ing4 mediated regulation of overlapping signaling pathways that regulate stem cell activity and cancer cells, including NF-B and c-Myc. In a two-part study, we have investigated the role of Ing4 in murine hematopoiesis and human malignancies. While the specific mechanisms of stem cell self-renewal, maintenance, and differentiation are poorly characterized, we have determined …

Quadratic Neural Network Architecture As Evaluated Relative To Conventional Neural Network Architecture, Reid Taylor

Senior Theses

Current work in the field of deep learning and neural networks revolves around several variations of the same mathematical model for associative learning. These variations, while significant and exceptionally applicable in the real world, fail to push the limits of modern computational prowess. This research does just that: by leveraging high order tensors in place of 2nd order tensors, quadratic neural networks can be developed and can allow for substantially more complex machine learning models which allow for self-interactions of collected and analyzed data. This research shows the theorization and development of mathematical model necessary for such an idea to …

In Vitro And In Vivo Studies Of Mediator Kinase, Lili Wang

Theses and Dissertations

This project addresses the molecular and in vivo activities of transcriptionregulating module CKM, comprised of CDK8 (or CDK19) kinases, Cyclin C, MED12 and MED13. Our lab has found that CDK8/19 potentiates NFkB-induced transcription. In this study, we confirmed that both CDK8 and CDK19 regulate gene expression in kinasedependent manner. CDK8 and CDK19 are not required for NFkB-induced transcription, which also occurs in HEK293-dKO (CDK8 and CDK19 double knockout) cells, but such transcription becomes CDK8/19-dependent upon re-expression of CDK8 or CDK19 in dKO. Surprisingly. pre-treatment with a CDK8/19 inhibitor decreases the effect of CDK8/19 on NFkB-induced transcription.

In another set of …

Mechanistic Multiphysics Modeling Of Cladding Rupture In Nuclear Fuel Rods During Loss-Of-Coolant Accident Conditions, Kyle Allan Lawrence Gamble

Theses and Dissertations

The Loss of Coolant Accident (LOCA) is a design basis accident that is included as part of the safety analysis of nuclear power plants. As the nuclear industry desires to increase the cycle length and discharge burnup of existing nuclear power plants they must demonstrate safe operation during a LOCA on high burnup fuel. During a LOCA transient on high burnup fuel rods, the rods may undergo a process known as fuel fragmentation, relocation, and dispersal (FFRD). To permit dispersal, the cladding encapsulating the fuel must rupture with an opening size large enough to allow the fragmented fuel particles to …

The Submission Of A Section 513(G) Request For Information, Morgan Ashley Lano

Theses and Dissertations

The Food and Drug Administration designates all medical devices into one of three general classes contingent on their intended use, indications for use, and potential risk to the user. This classification dictates the further path the device must take to be approved for the commercial market. Section 513(g) of the Federal Food, Drug, and Cosmetic Act (21 U.S.C. 360c(g)) is submitted in order to gain the agency’s unofficial classification and suggested regulatory requirements. The Coagulation Companion (MicroVide) is a device designed to fluorescently quantify a key enzyme involved in the coagulation cascade, plasmin, in pediatric patients. clot formation and degradation …

Coalitional Game Theory For Stormwater Management And Green Infrastructure Practices, Carly Lawyer

Theses and Dissertations

As global warming and climate Variability bring about more frequent and intense rainstorms and accelerate sea level rise, our social and built environments are at heightened risk of flood induced damages and consequent costs. This is particularly true for coastal areas, facing the coupled effects of these threats while serving as home to people, businesses, unique landscapes, and historic landmarks. Complex decisions at all levels of government and community planning stand to benefit from increased understanding of possible outcomes and pathways resulting from decentralized human behavior and decision making in the realm of water resources engineering and management. Game theory …

Deep Learning Based Generative Materials Design, Yong Zhao

Theses and Dissertations

Discovery of novel functional materials is playing an increasingly important role in many key industries such as lithium batteries for electric vehicles and cell phones. However experimental tinkering of existing materials or Density Functional Theory (DFT) based screening of known crystal structures, two of the major current materials design approaches, are both severely constrained by the limited scale (around 250,000 in ICSD database) and diversity of existing materials and the lack of a sufficient number of materials with annotated properties. How to generate a large number of physically feasible, stable, and synthesizable crystal materials and build accurate property prediction models …

Developing An Optimized Policy Tree-Based Reservoir Operation Model For High Aswan Dam Reservoir, Nile River, Erfan Goharian, Mohamed Shaltout, Mahdi Erfani, Ahmed Eladawy

Faculty Publications

The impacts of climate change on the Nile River and Grand Ethiopian Renaissance Dam (GERD) along with the increased water demand downstream suggest an urgent need for more efficient management of the reservoir system that is well-informed by accurate modeling and optimization of the reservoir operation. This study provides an updated water balance model for Aswan High Dam Reservoir, which was validated using combined heterogeneous sources of information, including in situ gauge data, bias-corrected reanalyzed data, and remote sensing information. To investigate the future challenges, the spatial distribution of the annual/seasonal Aswan High Dam Reservoir surface air temperature trends over …

Developing An Optimized Policy Tree-Based Reservoir Operation Model For High Aswan Dam Reservoir, Nile River, Erfan Goharian, Mohamed Shaltout, Mahdi Erfani, Ahmed Eladawy

Faculty Publications

The impacts of climate change on the Nile River and Grand Ethiopian Renaissance Dam (GERD) along with the increased water demand downstream suggest an urgent need for more efficient management of the reservoir system that is well-informed by accurate modeling and optimization of the reservoir operation. This study provides an updated water balance model for Aswan High Dam Reservoir, which was validated using combined heterogeneous sources of information, including in situ gauge data, bias-corrected reanalyzed data, and remote sensing information. To investigate the future challenges, the spatial distribution of the annual/seasonal Aswan High Dam Reservoir surface air temperature trends over …

Managing Aquifer Recharge To Overcome Overdraft In The Lower American River, California, Usa, Mahesh L. Maskey, Mustafa S. Dogan, Angel Santiago Fernandez-Bou, Liying Li, Alexander Guzman, Wyatt Arnold, Erfan Goharian, Jay R. Lund, Josue Medellin-Azuara

Faculty Publications

Frequent and prolonged droughts challenge groundwater sustainability in California but managing aquifer recharge can help to partially offset groundwater overdraft. Here, we use managed aquifer recharge (MAR) to examine potential benefits of adding an artificial recharge facility downstream from California’s Lower American River Basin, in part to prepare for drought. We use a statewide hydroeconomic model, CALVIN, which integrates hydrology, the economics of water scarcity cost and operations, environmental flow requirements, and other operational constraints, and allocates water monthly to minimize total scarcity and operating costs. This study considers a recharge facility with unconstrained and constrained flows. The results show …

Intermediate Temperature Solid Oxide Cell With A Barrier Layer Free Oxygen Electrode And Phase Inversion Derived Hydrogen Electrode, Yongliang Zhang, Nansheng Xu, Qiming Tang, Kevin Huang

Faculty Publications

High-temperature solid oxide cells (SOCs) have fundamental advantages in efficiency and product rate over their low-temperature counterparts. However, the commercial development of SOCs is hindered by cost and reliability. To solve the issues, lowering the operating temperature of SOCs is deemed the best solution. Here we report on our effort toward intermediate temperature (IT) SOCs by developing a barrier layer free high-performance oxygen electrode and open structured hydrogen electrode. The results show that the new oxygen electrode provides reasonably good oxygen electrocatalytic activity at IT range for oxygen reduction and evolution reactions and the open structured hydrogen electrode provides low …

Electron Mobility And Velocity In Ai 0.45 Ga 0.55 N-Channel Ultra-Wide Bandgap Hemts At High Temperatures For Rf Power Applications, Hansheng Ye, Mikhail Gaevski, Grigory Simin, Asif Khan, Patrick Fay

Faculty Publications

Ultra-wide bandgap AlGaN has attracted recent attention as a promising channel material for next-generation high electron mobility transistors (HEMTs) for RF power due to its high critical field, excellent transport properties, and potential for operation in extreme environments. However, the effects of temperature on the transport properties are not fully understood. Here, Al_0.62Ga_0.38N/Al_0.45Ga_0.55N HEMTs have been fabricated and characterized up to 150 °C at DC and RF to evaluate the effect of temperature on electron mobility and carrier velocity. Measured results indicate that both mobility and carrier velocity exhibit modest dependence on …

Fourth-Order Adjoint Sensitivity And Uncertainty Analysis Of An Oecd/Nea Reactor Physics Benchmark: Ii. Computed Response Uncertainties, Ruixian Fang, Dan Gabriel Cacuci

Faculty Publications

This work quantifies the impact of the most important 4th-order sensitivities of the leakage response of a polyethylene-reflected plutonium (PERP) reactor physics benchmark with respect to the benchmark’s 180 group-averaged microscopic total cross sections, on the expected value, variance and skewness of the benchmark’s leakage response. This work shows that, as the standard deviations of the cross sections increase, the contributions of the 4th-order sensitivities to the response’s expected value and variance become significantly larger than the corresponding contributions stemming from the 1st-, 2nd- and 3rd-order sensitivities. Considering a uniform 5% relative standard deviation for all microscopic total cross sections, …

Kinetic And Thermodynamic Analyses For Pyrolysis Of Hemp Hurds Using Discrete Distributed Activation Energy Model, Panuphong Mankeed, Thossaporn Onsree, Salman Raza Naqvi, Sirivatch Shimpalee, Nakorn Tippayawong

Faculty Publications

In many counties, hemp is becoming a high-valued economic crop. Post-processing, more than 65% w/w of its starting material becomes waste. Herein, pyrolysis of hemp hurds/residues was investigated under low (10-50 degrees C/min) and intermediate (100-150 degrees C/min) heating rates using a discrete distributed activation energy model (DAEM). Thermochemical decomposition of hemp hurds occurred in three stages: drying, active pyrolysis, and char formation, accounting for 70-80% w/w overall weight loss. With the discrete DAEM, the model can be utilized for predicting pyrolysis behaviors of hemp hurds accurately with correlation coefficient of over 0.99. Different reaction mechanisms appeared between the low …

Decellularized Articular Cartilage Microgels As Microcarriers For Expansion Of Mesenchymal Stem Cells, Esmaiel Jabbari, Azadeh Sepahvandi

Faculty Publications

Conventional microcarriers used for expansion of human mesenchymal stem cells (hMSCs) require detachment and separation of the cells from the carrier prior to use in clinical applications for regeneration of articular cartilage, and the carrier can cause undesirable phenotypic changes in the expanded cells. This work describes a novel approach to expand hMSCs on biomimetic carriers based on adult or fetal decellularized bovine articular cartilage that supports tissue regeneration without the need to detach the expanded cells from the carrier. In this approach, the fetal or adult bovine articular cartilage was minced, decellularized, freeze-dried, ground, and sieved to produce articular …

Decellularized Articular Cartilage Microgels As Microcarriers For Expansion Of Mesenchymal Stem Cells, Esmaiel Jabbari, Azadeh Sepahvandi

Faculty Publications

Conventional microcarriers used for expansion of human mesenchymal stem cells (hMSCs) require detachment and separation of the cells from the carrier prior to use in clinical applications for regeneration of articular cartilage, and the carrier can cause undesirable phenotypic changes in the expanded cells. This work describes a novel approach to expand hMSCs on biomimetic carriers based on adult or fetal decellularized bovine articular cartilage that supports tissue regeneration without the need to detach the expanded cells from the carrier. In this approach, the fetal or adult bovine articular cartilage was minced, decellularized, freeze-dried, ground, and sieved to produce articular …

Fourth-Order Comprehensive Adjoint Sensitivity Analysis Methodology For Nonlinear Systems (4th-Casam-N): I. Mathematical Framework, Dan Gabriel Cacuci

Faculty Publications

This work presents the fourth-order comprehensive sensitivity analysis methodology for nonlinear systems (abbreviated as “4th-CASAM-N”) for exactly and efficiently computing the first-, second-, third-, and fourth-order functional derivatives (customarily called “sensitivities”) of physical system responses (i.e., “system performance parameters”) to the system’s (or model) parameters. The qualifier “comprehensive” indicates that the 4th-CASAM-N methodology enables the exact and efficient computation not only of response sensitivities with respect to the customary model parameters (including computational input data, correlations, initial and/or boundary conditions) but also with respect to imprecisely known material boundaries, caused by manufacturing tolerances, of the system under consideration. The 4th-CASAM-N …

Large Scale Dataset Of Real Space Electronic Charge Density Of Cubic Inorganic Materials From Density Functional Theory (Dft) Calculations, Fancy Qian Wang, Kamal Choudhary, Jianjun Hu, Ming Hu

Faculty Publications

Driven by the big data science, material informatics has attracted enormous research interests recently along with many recognized achievements. To acquire knowledge of materials by previous experience, both feature descriptors and databases are essential for training machine learning (ML) models with high accuracy. In this regard, the electronic charge density ρ(r), which in principle determines the properties of materials at their ground state, can be considered as one of the most appropriate descriptors. However, the systematic electronic charge density ρ(r) database of inorganic materials is still in its infancy due to the difficulties in …

Strong Laser Polarization Control Of Coherent Phonon Excitation In Van Der Waals Material Fe3Gete2, Yu Gong, Ming Hu, Nico Harris, Zhonghua Yang, Ti Xie, Alem Teklu, Narayanan Kuthirummal, Jacob Koenemann, Xianghan Xu, Sang-Wook Cheong, Will Mcloud, Cheng Gong

Faculty Publications

Optical manipulation of coherent phonon frequency in two-dimensional (2D) materials could advance the development of ultrafast phononics in atomic-thin platforms. However, conventional approaches for such control are limited to doping, strain, structural or thermal engineering. Here, we report the experimental observation of strong laser-polarization control of coherent phonon frequency through time-resolved pump-probe spectroscopic study of van der Waals (vdW) materials Fe₃GeTe₂. When the polarization of the pumping laser with tilted incidence is swept between in-plane and out-of-plane orientations, the frequencies of excited phonons can be monotonically tuned by as large as 3% (~100 GHz). Our first-principles …

Hippocampal Ensembles Represent Sequential Relationships Among An Extended Sequence Of Nonspatial Events, Babak Shahbaba, Lingge Li, Forest Agostinelli, Mansi Saraf, Keiland W. Cooper, Derenik Haghverdian, Gabriel A. Elias, Pierre Baldi, Norbert J. Fortin

Faculty Publications

The hippocampus is critical to the temporal organization of our experiences. Although this fundamental capacity is conserved across modalities and species, its underlying neuronal mechanisms remain unclear. Here we recorded hippocampal activity as rats remembered an extended sequence of nonspatial events unfolding over several seconds, as in daily life episodes in humans. We then developed statistical machine learning methods to analyze the ensemble activity and discovered forms of sequential organization and coding important for order memory judgments. Specifically, we found that hippocampal ensembles provide significant temporal coding throughout nonspatial event sequences, differentiate distinct types of task-critical information sequentially within events, …

Concurrent Identification And Characterization Of Protein Structure And Continuous Internal Dynamics With Redcraft, Hanin Omar, Aaron Hein, Casey A. Cole, Homayoun Valafar

Faculty Publications

Internal dynamics of proteins can play a critical role in the biological function of some proteins. Several well documented instances have been reported such as MBP, DHFR, hTS, DGCR8, and NSP1 of the SARS-CoV family of viruses. Despite the importance of internal dynamics of proteins, there currently are very few approaches that allow for meaningful separation of internal dynamics from structural aspects using experimental data. Here we present a computational approach named REDCRAFT that allows for concurrent characterization of protein structure and dynamics. Here, we have subjected DHFR (PDB-ID 1RX2), a 159-residue protein, to a fictitious, mixed mode model of …

An Artificial Intelligence Approach To Fatigue Crack Length Estimation From Acoustic Emission Waves In Thin Metallic Plates, Joseph Chandler Garrett, Hanfei Mei, Victor Giurgiutiu

Faculty Publications

The acoustic emission (AE) technique has become a well-established method of monitoring structural health over recent years. The sensing and analysis of elastic AE waves, which have involved piezoelectric wafer active sensors (PWAS) and time domain and frequency domain analysis, has proven to be effective in yielding fatigue crack-related information. However, not much research has been performed regarding (i) the correlation between the fatigue crack length and AE signal signatures and (ii) artificial intelligence (AI) methodologies to automate the AE waveform analysis. In this paper, this crack length correlation is investigated along with the development of a novel AE signal …

Surface Acoustic Wave (Saw) Sensors: Physics, Materials, And Applications, Debdyuti Mandal, Sourav Banerjee

Faculty Publications

Surface acoustic waves (SAWs) are the guided waves that propagate along the top surface of a material with wave vectors orthogonal to the normal direction to the surface. Based on these waves, SAW sensors are conceptualized by employing piezoelectric crystals where the guided elastodynamic waves are generated through an electromechanical coupling. Electromechanical coupling in both active and passive modes is achieved by integrating interdigitated electrode transducers (IDT) with the piezoelectric crystals. Innovative meta-designs of the periodic IDTs define the functionality and application of SAW sensors. This review article presents the physics of guided surface acoustic waves and the piezoelectric materials …

Effect Of Defects Part I: Degradation Of Constitutive Coefficients As An Input To The Composite Failure Model With Microvoids And Porosity, Vahid Tavaf, Sourav Banerjee

Faculty Publications

It is always challenging to provide appropriate material properties for a composite progressive failure model. The nonstandard percentage reduction method that is commonly used to degrade the material constants with micro-scale defects generates tremendous uncertainty in failure prediction. The constitutive matrix is composed of multiple material constants. It is not necessary that all constants degrade either equally or linearly due to a certain state of material defects. With this very concern in mind, this article presents a guideline for using a quantified perturbation for each coefficient appropriately. It also presents distribution of effective material properties (EMPs) in unidirectional composite materials …