Engineering Commons^™

Modeling Complex Oxides: Thermochemical Behavior Of Nepheline-Forming Na-Al-Si-B-K-Li-Ca-Mg-Fe-O And Hollandite-Forming Ba-Cs-Ti-Cr-Al-Fe- Ga-O Systems, Stephen A. Utlak

Theses and Dissertations

High concentrations of Na2O and Al2O3 in the liquid high-level radioactive waste (HLW) stored at the Hanford Site can cause nepheline (NaAlSiO4) to precipitate in a vitrified monolithic waste form upon cooling. Nepheline phase formation removes glass- former SiO2 and -modifier Al2O3 from the immobilization matrix in greater proportion to alkalis, which can reduce glass durability and consequently increase the leach rate of radionuclides into the surrounding environment.

Current uncertainty in defining the HLW glass composition region prone to precipitating nepheline necessitates targeting a conservative waste loading, which raises operational costs by extending the liquid radioactive waste disposal mission and …

Three-Dimensional Plasma Cell Survival Microniche In Multiple Myeloma, Katrina A. Harmon

Theses and Dissertations

Multiple myeloma (MM) is an incurable malignancy characterized by the uncontrolled proliferation of long-lived plasma cells (PCs) in the bone marrow (BM), which constitute at least 10% of BM cellularity. Normally, long-lived plasma cells make up less than 1% of BM cells. Plasma cells become neoplastic when a clonal PC population produces a monoclonal immunoglobulin protein. A diagnosis of monoclonal gammopathy of undetermined significance (MGUS) is made when there is an increase in monoclonal PCs within the BM, but less than 10%, and the patient does not present with end-organ damage, which is associated with active MM. Though not considered …

Plasma Surface Functionalization Of Afp Manufactured Composites For Improved Adhesive Bond Performance, Ibrahim Sarikaya

Theses and Dissertations

High-performance composite structures not only require a reliable fabrication process when creating primary structures, but also a high fidelity and repeatable bonding process for the assembled components. During the assembly process, surface contaminants are a major concern as they have the potential to compromise the bond quality resulting in poor bond strength, low failure load, and undesirable failure modes of the adhesively bonded structures. This is further complicated by composite materials inherently possessing low surface energy and thus exhibiting low adhesive property. Therefore, detecting and removing contaminants on the pre-bond composite surface is an active research topic in pursuit of …

Development Of Scalable And Tunable Super- Hydrophilic And - Hydrophobic Coatings On The Cu Substrate For Phase Change Heat Transfer Applications, Raikan Saad Dawas

Theses and Dissertations

The aim of this study is to enhance and sustain the thin liquid film evaporation (TLFE) as well as dropwise condensation (DWC) on scalable copper substrates. The current dissertation consists of two sections. The objective of the first section is to enhance the dry cooling technology which is widely used in industrial applications such as in the air side of power plants, AC unit, or electronic cooling. However, the thermal dissipation performance is limited with low heat transfer coefficients (HTCs) due to the low thermal conductivity and density of the air. Inspired by the phase change heat transfer during the …

Continuous Tow Path Generation For Constant And Variable Stiffness Composite Laminates On Single And Double Curved Surfaces, Caleb R. Pupo

Theses and Dissertations

A novel approach for the generation of steered tow paths on curved shell surfaces is presented. The approach is used to translate optimal theoretical analysis expressed from ply to ply as fiber angle distributions for steered laminates into discrete tow paths on planar, single and double curved surfaces. By adapting the multi mesh approach earlier developed by van Tooren and Elham [1–3] to the new tow path generation code. Two meshes are utilized, a coarse mesh which is generated during the optimization and contains the optimal fiber angle distributions, and a denser mesh obtained from tessellating the surface to better …

Beneficial Effects Of Resveratrol Against Colitis And Colorectal Cancer Mediated By The Host Microbiome, Epigenome, And Immune Response, Haider Rasheed Daham Alrafas

Theses and Dissertations

Resveratrol, a natural polyphenol compound found in red wine, the skins of grapes, and other plant products, has been used as a traditional medicine for thousands of years throughout human history, but current research has revealed this natural component is capable of modulating a variety of immunological, microbial, and epigenetic mechanisms to improve overall health and well-being of hosts that consume it. Colitis, an inflammatory bowel disease characterized by chronic inflammation in the colon and rectum, which has been associated with colon cancer. This cancer incidence is rising in younger adults in the US. Thus, newer approaches to prevent colitis …

Electrode Development And Electrocatalysts Design For Polymer Electrolyte Membrane Fuel Cells, Xiong Peng

Theses and Dissertations

Because of environmental issues and national conflicts caused by overuse of fossil fuels, there is a need to seek renewable ways to utilize energy. In the transportation sector, hydrogen-based polymer electrolyte membrane fuel cells, including proton exchange membrane fuel cells (PEMFCs) and anion exchange membrane fuel cells (AEMFCs), have been considered as a promising alternative to conventional combustion engines. However, the widespread commercialization of both PEMFCs and AEMFCs has been hindered by several factors, including cost and performance. In this thesis, a series of topics including electrode fabrication, electrocatalyst development for both PEMFCs and AEMFCs, as well as the water …

Path Loss Models For Two Small Airport Indoor Environments At 31 Ghz, Alexander L. Grant

Theses and Dissertations

Path loss modeling plays a fundamental role in the design of fixed and mobile communication systems for a range of applications. Another term for path loss is channel attenuation, or reduction in signal power from transmitter to receiver. Work here was in support of a NASA project for advanced air traffic management (ATM) applications, specifically for improving the efficiency of airports. Measurements in the millimeter wave (mmWave) band were conducted at 31 GHz in indoor settings at a small municipal airport, the Jim Hamilton–L.B. Owens Airport, in Columbia, SC. Some measurements were also taken at 5 GHz for comparison. A …

Low Frequency Injection As A Method Of Low-Level Dc Microgrid Communication, Matthew Davidson

Theses and Dissertations

In the last ten years, DC microgrid approaches have gained more popularity for the interconnection of distributed energy resources (DERs) and prosumers. The devices (generation, storage, and load) connected to the network may contain operational parameters that have the ability to be adjusted in real-time as to optimize the operation of the microgrid. In this thesis, a simple unidirectional global communication scheme is defined, implemented, and tested. The proposed approach relies on low frequency sinusoidal components that are injected into the DC microgrid power lines. Using the proposed communication approach, multiple parameters can be transmitted to the devices connected to …

Surface Science And Engineering Of Nano-Structured Cathodes For Intermediate Temperature Solid Oxide Fuel Cells, Yeting Wen

Theses and Dissertations

The bulk-to-surface Sr-segregation can seriously compromise the stability of oxygen electrocatalysis in Sr-doped perovskite oxides such as La1-xSrxCoO3-δ and La1-xSrxCo1- yFeyO3-δ and limit their practical applications as cathode materials in solid oxide fuel cells. Although such chemical instability has been actively studied in recent years, fundamental understanding of Sr-segregation process vs temperature and time, particularly under real-world conditions, as well as the suppression method, are still needed. This PhD dissertation aims to acquire fundamental knowledge of Sr-segregation process under practical conditions in solid oxide fuel cells and develop suppression method to ensure the long-term stability through surface modifications.

To gain …

Acoustoelastic Metamaterial With Simultaneous Noise Filtering And Energy Harvesting Capability From Ambient Vibrations, Fariha Mir

Theses and Dissertations

Harvesting unused and untapped energy from ambient vibration noise and acoustic sound waves is an emerging field of research in the recent years. Utilization of the energy with a wide band of the frequency spectrum from the vibrational sources alone stands as one of the most promising ways to power small electronic devices, smartphones, local structural health monitoring (SHM) sensors and home and workshop appliances. Various sources of ambient vibration and acoustic noise can be found around us in our everyday life. These sources are abundant in almost all the engineering industries and manufacturing facilities for example in aerospace, mechanical …

Landslide Detection Using Remote Sensing Methods A Review Of Current Techniques, Sumanth Varma Byrraju

Theses and Dissertations

Landslides are among the most dangerous natural disasters, as they generally follow other major disasters thereby causing significant damage to already weakened systems. In the U.S. alone they cause an excess of 1 billion in damages and an average 25-50 deaths annually(USGC). Remote sensing techniques for landslide monitoring and prediction has gained popularity in recent years since it enables hazard mitigation. Synthetic Aperture Radar (SAR) interferometry is among the remote sensing techniques used. DInSAR is an advanced interferometric technique which uses radar sensors to estimate the phase of a given area from which the landslide activity can be predicted. The …

The Use Of Multi-Targeting Natural Products For The Treatment Of Cancer, Wesley Taylor

Theses and Dissertations

The paradigm shift in cancer treatments from traditional chemotherapeutics to targeted therapies has rapidly improved prognoses for patients for whom cancer was once a death sentence. This is especially true in the case of targeted immune therapies which activate the body’s own natural defense system to fight cancer. Despite these advances, however, cancer remains the second leading cause of death in the United States. The promise of targeted therapeutics has faced significant hurdles in providing effective cancer treatments, namely the limited percentage of susceptible cancers for each treatment, high cost burden, high toxicities, and significant risk of treatment induced resistance. …

Friction Stir Additive Manufacturing(Fsam) Of 2050 Al-Cu-Li Alloy, Ilana Lu

Theses and Dissertations

As a solid state process, friction stir welding (FSW) is an advantageous joining method for higher strength aluminum alloys such as 2050 Al-Cu-Li which are not readily fusion welded. This study explores the potential of friction stir lap welding (FSLW) as an additive manufacturing process for this aluminum-lithium alloy. To accomplish this, lap weld joints were performed so that each additional layer would penetrate the preceding weld pass which creates a large, stacked build. Excess material is machined away leaving only weld. Cast AA2050 is explored in this study as a more cost-efficient feedstock for this process as compared to …

A Partially Automated Process For The Generation Of Believable Human Behaviors, Bridgette Parsons

Theses and Dissertations

Modeling believable human behavior for use in simulations is a difficult task. It re- quires a great deal of time, and frequently requires coordination between members of different disciplines. In our research, we propose a method of partially automating the process, reducing the time it takes to create the model, and more easily allowing domain experts that are not programmers to adjust the models as necessary. Using Agent-Based modeling, we present MAGIC (Models Automatically Generated from Information Collected), an algorithm designed to automatically find points in the model’s decision process that require interaction with other agents or with the sim- …

Bridgr: An Ios Application For Organizing And Discussing Long-Distance Carpooling, Harrison Engoren, Erik Zorn

Senior Theses

Bridgr is an iOS application that facilitates long distance carpooling. This application allows drivers to post destinations on an interactable map so that they can be linked with students that need a ride to a location within close proximity of the posted destination. The riders and driver are linked in a common chat board where they can discuss ride details among themselves. The goal of Bridgr is to allow drivers to utilize extra space in their car in turn for fellowship and/or gas money.

Process Design: Maleic Anhydride Unit, Valerie Kay, Jacqueline Phillips, Olivia Smithson

Senior Theses

Gamecock Chemical Company has proposed the construction of a maleic anhydride plant at its Houston refinery. The plant is to produce 40,000 metric tons per year of maleic anhydride from a mixture of excess butanes. This design team has been asked to produce a conceptual design, simulation, and profitability analysis for the proposed plant. The simulation software Aspen Plus by AspenTech was the primary software used to design the plant, and the CAPCOST program in Microsoft suite’s Excel was utilized for the economic review of the process.

Maleic anhydride is produced by the thermal oxidation of n-butane at an elevated …

Constrained Consensus In Continuous-Time Multi-Agent Systems, Zheqing Zhou

Theses and Dissertations

Since the consensus problem is getting popular in recent researches and the applications based on it are expanding in current years! the consensus problem under the condition that constraints exist on agents’ state in continuous-time in a multi-agent system has been studied here. This work combines the projection operator method in a general consensus algorithm to avoid the violation of state on its individual constraint set. When the projection operator works in the general consensus algorithm, the constraint region is divided into the projection-operator working region and the non-projection region. The boundary between these two regions is a circular line. …

Experimental Study Of Free-Solution Separation Under Pulsed Electrophoresis In Microchip, Xin Liu

Theses and Dissertations

Microchip electrophoresis (MCE) is a promising analytical tool started more than two decades. With the characteristics of short analysis time, trace level sample, high- throughput and easily integration, lots of efforts have been done with the transportation of the applications from capillary to microfabricated devices. However, with the complex designs on microchip rather than a single straight capillary channel, the strategies and approaches have to be figured out under the challenges of sample introduction, the improvement of separation conditions and the detection, for instance.

In miniaturized microchip, the separation channel is reduced to several centimeters or less, fast and quality …

Modeling Complex Oxides: Thermochemical Behavior Of Nepheline-Forming Na-Al-Si-B-K-Li-Ca-Mg-Fe-O And Hollandite-Forming Ba-Cs-Ti-Cr-Al-Fe- Ga-O Systems, Stephen A. Utlak

Theses and Dissertations

High concentrations of Na2O and Al2O3 in the liquid high-level radioactive waste (HLW) stored at the Hanford Site can cause nepheline (NaAlSiO4) to precipitate in a vitrified monolithic waste form upon cooling. Nepheline phase formation removes glass- former SiO2 and -modifier Al2O3 from the immobilization matrix in greater proportion to alkalis, which can reduce glass durability and consequently increase the leach rate of radionuclides into the surrounding environment.

Current uncertainty in defining the HLW glass composition region prone to precipitating nepheline necessitates targeting a conservative waste loading, which raises operational costs by extending the liquid radioactive waste disposal mission and …

High-Performing Pgm-Free Aemfc Cathodes From Carbon-Supported Cobalt Ferrite Nanoparticles, Xiong Peng, Varchaswal Kashyap, Benjamin Ng, Sreekumar Kurungot, Lianqin Wang, John R. Varcoe, Mustain E William

Faculty Publications

Efficient and durable non-precious metal electrocatalysts for the oxygen reduction reaction (ORR) are highly desirable for several electrochemical devices, including anion exchange membrane fuel cells (AEMFCs). Here, cobalt ferrite (CF) nanoparticles supported on Vulcan XC-72 carbon (CF-VC) were created through a facile, scalable solvothermal method. The nano-sized CF particles were spherical with a narrow particle size distribution. The CF-VC catalyst showed good ORR activity, possessing a half-wave potential of 0.71 V. Although the intrinsic activity of the CF-VC catalyst was not as high as some other platinum group metal (PGM)-free catalysts in the literature, where this catalyst really shined was …

Diagnosis Of Brain Diseases Via Multi-Scale Time-Series Model, Zehua Zhang, Junhai Xu, Jijun Tang, Quan Zou, Fei Guo

Faculty Publications

The functional magnetic resonance imaging (fMRI) data and brain network analysis have been widely applied to automated diagnosis of neural diseases or brain diseases. The fMRI time series data not only contains specific numerical information, but also involves rich dynamic temporal information, those previous graph theory approaches focus on local topology structure and lose contextual information and global fluctuation information. Here, we propose a novel multi-scale functional connectivity for identifying the brain disease via fMRI data. We calculate the discrete probability distribution of co-activity between different brain regions with various intervals. Also, we consider nonsynchronous information under different time dimensions, …

Electrochemical Conversion Of Methane To Ethylene In A Solid Oxide Electrolyer, Changli Zhu, Shisheng Hou, Xiuli Hu, Jinhai Lu, Fanglin Chen, Kui Xie

Faculty Publications

Conversion of methane to ethylene with high yield remains a fundamental challenge due to the low ethylene selectivity, severe carbon deposition and instability of catalysts. Here we demonstrate a conceptually different process of in situ electrochemical oxidation of methane to ethylene in a solid oxide electrolyzer under ambient pressure at 850 °C. The porous electrode scaffold with an in situ-grown metal/oxide interface enhances coking resistance and catalyst stability at high temperatures. The highest C2 product selectivity of 81.2% together with the highest C2 product concentration of 16.7% in output gas (12.1% ethylene and 4.6% ethane) is achieved while the methane …

Controlling The Oxygen Electrocatalysis On Perovskite And Layered Oxide Thin Films For Solid Oxide Fuel Cell Cathodes, Gene Yang, Wonsang Jung, Sung-Jin Ahn, Dongkyu Lee

Faculty Publications

Achieving the fast oxygen reduction reaction (ORR) kinetics at the cathode of solid oxide fuel cells (SOFCs) is indispensable to enhance the efficiency of SOFCs at intermediate temperatures. Mixed ionic and electronic conducting (MIEC) oxides such as ABO₃ perovskites and Ruddlesden-Popper (RP) oxides (A₂BO₄) have been widely used as promising cathode materials owing to their attractive physicochemical properties. In particular, oxides in forms of thin films and heterostructures have enabled significant enhancement in the ORR activity. Therefore, we aim to give a comprehensive overview on the recent development of thin film cathodes of SOFCs. We …

Material And Regenerative Properties Of An Osteon-Mimetic Cortical Bone-Like Scaffold, Danial Barati, Ozan Karaman, Seyedsina Moeinzadeh, Safaa Kader, Esmaiel Jabbari

Faculty Publications

The objective of this work was to fabricate a rigid, resorbable and osteoconductive scaffold by mimicking the hierarchical structure of the cortical bone. Aligned peptide-functionalize nanofiber microsheets were generated with calcium phosphate (CaP) content similar to that of the natural cortical bone. Next, the CaP-rich fibrous microsheets were wrapped around a microneedle to form a laminated microtube mimicking the structure of an osteon. Then, a set of the osteon-mimetic microtubes were assembled around a solid rod and the assembly was annealed to fuse the microtubes and form a shell. Next, an array of circular microholes were drilled on the outer …

Coupling Computational Fluid Dynamics Simulations And Statistical Moments For Designing Healthy Indoor Spaces, Shamia Hoque, Firoza B. Omar

Faculty Publications

Cross-contamination between occupants in an indoor space may occur due to transfer of infectious aerosols. Computational fluid dynamics (CFD) provides detailed insight into particle transport in indoor spaces. However, such simulations are site-specific. This study couples CFD with statistical moments and establishes a framework that transitions site-specific results to generating guidelines for designing “healthy” indoor spaces. Eighteen cases were simulated, and three parameters were assessed: inlet/outlet location, air changes per hour, and the presence/absence of desks. Aerosol release due to a simulated “sneeze” in a two-dimensional ventilated space was applied as a test case. Mean, standard deviation, and skewness of …

Application Of The Second-Order Comprehensive Adjoint Sensitivity Analysis Methodology To Compute First- And Second-Order Sensitivities Of Flux Functionals In A Multiplying System With Source, Dan Gabriel Cacuci

Faculty Publications

This work presents an application of the Second-Order Adjoint Sensitivity Analysis Methodology (2nd-ASAM) to the neutron transport Boltzmann equation that models a multiplying subcritical system comprising a nonfission neutron source to compute efficiently and exactly all of the first- and second-order functional derivatives (sensitivities) of a detector’s response to all of the model’s parameters, including isotopic number densities, microscopic cross sections, fission spectrum, sources, and detector response function. As indicated by the general theoretical considerations underlying the 2nd-ASAM, the number of computations required to obtain the first and second orders increases linearly in augmented Hilbert spaces as opposed to increasing …

Obstacles To Translating The Promise Of Nanoparticles Into Viable Amyloid Disease Therapeutics, N. P. Van Der Munnik, M. A. Moss, M. J. Uline

Faculty Publications

Nanoparticles (NPs) constitute a powerful therapeutic platform with exciting prospects as potential inhibitors of amyloid-β (Aβ) aggregation, a process associated with Alzheimer's disease (AD). Researchers have synthesized and tested a large collection of NPs with disparate sizes, shapes, electrostatic properties and surface ligands that evoke a variety of responses on Aβ aggregation. In spite of a decade of research on the NP-Aβ system and many promising experimental results, NPs have failed to progress to any level of clinical trials for AD. A theoretical framework with which to approach this physical system is presented featuring two simple metrics, (1) the extent …

Discovering Cancer Subtypes Via An Accurate Fusion Strategy On Multiple Profile Data, Limin Jiang, Yongkang Xiao, Yijie Ding, Jijun Tang, Fei Guo

Faculty Publications

Discovering cancer subtypes is useful for guiding clinical treatment of multiple cancers. Progressive profile technologies for tissue have accumulated diverse types of data. Based on these types of expression data, various computational methods have been proposed to predict cancer subtypes. It is crucial to study how to better integrate these multiple profiles of data. In this paper, we collect multiple profiles of data for five cancers on The Cancer Genome Atlas (TCGA). Then, we construct three similarity kernels for all patients of the same cancer by gene expression, miRNA expression and isoform expression data. We also propose a novel unsupervised …

High-Throughput 3d Reconstruction Of Stochastic Heterogeneous Microstructures In Energy Storage Materials, Yanxiang Zhang, Mufu Yan, Yanhong Wan, Zhenjun Jiao, Yu Chen, Fanglin Chen, Changrong Xia, Meng Ni

Faculty Publications

Stochastic heterogeneous microstructures are widely applied in structural and functional materials, playing a crucial role in determining their performance. X-ray tomography and focused ion beam serial sectioning are frequently used methods to reconstruct three-dimensional (3D) microstructures, yet are demanding techniques and are resolution-limited. Here, a high-throughput multi-stage 3D reconstruction method via distance correlation functions is developed using a single representatively large-sized 2D micrograph for stochastic microstructures, and verified by X-ray micro-tomography datasets of isotropic and anisotropic solid oxide fuel cell electrodes. This method provides an economic, easy-to-use and high-throughput approach for reconstructing stochastic heterogeneous microstructures for energy conversion and storage …