Digital Commons Network^™

Abrasion Resistant Concrete Mix Design For Cold Climates, Diane Mariah Murph

Masters Theses

“Studded tire usage in Alaska contributes to rutting damage on pavements resulting in high maintenance costs and safety issues. In this study, binary, ternary, and quaternary highly-abrasion resistant concrete mix designs using supplementary cementitious materials (SCMs) were developed. The properties of fresh concrete and mechanical, and durability properties of hardened concrete for these mix designs were then tested to determine an optimum highly-abrasion resistant concrete mixture which could be placed in cold climates to reduce rutting damage. SCMs used included silica fume, ground granulated blast furnace slag, and type F fly ash. Tests including workability, air content, drying shrinkage, compressive …

Methane Dry Reforming Reaction On Cr, V, In, And Ga Supported Sapo-34 Zeolite, Ehigiator Festus Ojo

Masters Theses

”The CO₂ reforming of methane is a significant research area in mitigating and transforming two greenhouse gases for the production of syngas. The reaction has been investigated for four different promoted catalysts to determine their reactant's conversion, product’s selectivity, and their respective syngas ratios.

The catalytic test was investigated under atmospheric conditions at 600⁰C for 6.5h with a WHSV of 4800 ml g^-1 h^-1. The conversion and selectivity of catalysts 9Al 1V-inc SAPO-34, 9Al 1Cr-inc SAPO-34, 9Al 1Ga-inc SAPO-34, and 9Al 1In-inc SAPO-34 were analyzed. The CH₄ conversion for the different catalysts are, 9Al 1Cr-inc …

Unmanned Aerial And Traversing Vehicle -- A Mobile Platform For Bridge Inspections, Clayton A. Fritsche

Masters Theses

“Unmanned aerial vehicles (UAVs), also known as drones, have been rapidly growing in popularity since their creation. This study aimed to create a robotic platform used to assist in the inspection process of the nation’s aging and deteriorating bridges. To this end, a multimodal inspection robot that utilized both flying and driving technologies, was designed, analyzed, and tested for aerial, traversing, and their transitional operability. The design, herein referred to as the “BridgeBot”, was evaluated both computationally and experimentally. A finite element model of the BridgeBot was established and analyzed under static loading scenarios to help determine stress distributions and …

Development Of Castrip Dual Phase Steel, Brenton Allen Hrebec

Masters Theses

“Thermomechanical processing necessary to produce DP 980 steel using CASTRIP hot band was investigated. The resultant steel has an ultimate tensile strength of 1038 MPa, yield strength of 744 MPa, and total elongation of 8.6%. These mechanical properties were achieved by batch annealing the hot band at 649°C for 48 hours and cold rolling to a 20% reduction. The steel was continuously annealed to simulate a galvanization cycle with an intercritical temperature of 810°C. The possibility of improving the texture of the steel by warm rolling under dynamic strain aging conditions was investigated. Dynamic strain aging in the CASTRIP hot …

Performance Of One-Part And Two-Part Class C Fly Ash-Based Alkali Activated Mortars, Cedric Chani Kashosi

Masters Theses

“Seeking an eco-friendly concrete, researchers have conducted studies to fully replace ordinary Portland cement (OPC) with fly ash (FA) producing alkali-activated concrete (AAC). Results showed better performance of AAC in terms of high early compressive strength, and durability compared to conventional concrete. However, much is still unknown about the behavior of AAC. From the type of materials used, the curing procedure, and long-term strength development of these binders; a thorough investigation is needed in order to fill the existing gap from previous studies and thus make a step forward to the safely use of AAC in the construction industry. The …

Feasibility Study For Sustainable Controlled Low-Strength Material (Clsm) Incorporating Off-Specification Fly Ash And Bottom Ash, Alexis K. Vandomelen

Masters Theses

“Controlled low-strength material (CLSM) is a self-consolidating cementitious material used in applications requiring high flowability and low strength. The primary components of this material, being cement and sand, however, negatively impact the environment. Cement is a large contributor to CO2 emissions, and the vast depletion of sand causes physical and political issues. Furthermore, over 100 million short tons of coal combustion products (CCP), including fly ash and bottom ash, are created annually in the United States, while nearly half of all CCP remain unused. No off-specification fly ash has been implemented in CLSM. This study uses coal ashes sourced from …

Laser Machining Countersinks In Carbon Fiber Reinforced Polymer, Leon James Neely Hill

Masters Theses

“Laser machining countersinks with a frequency doubled Q-switched diode pumped Nd:YAG laser is demonstrated. Tests were conducted in 0.100" thick IM7 prepreg CFRP with [0,90]3S orientation. The HAZ is minimized to avoid stress concentrations in the epoxy matrix. A chamber and filtration system was designed and built to contain the byproducts produced in the machining process. The variables investigated are the number of repetitions in the offset path, the plunge rate, and the line energy. The research was performed over one baseline study, one parameter space exercise, two full factorial experiments, and one repeatability study. Assessment was done under an …

Inclusion Engineering In Femnal Steels, Rairu Vaz Penna

Masters Theses

"Low density high Mn and Al steels, or FeMnAl steels, show great promise for military vehicles and automotive applications in which high strength and toughness is a requirement. However, these steels are subject to processing challenges including development of oxide and nitride inclusions during melting and casting as well as a large as-cast grain size and heavy interdendritic segregation. This can lead to non-uniform heat treatment response and cracking during subsequent hot rolling. Adding up to 10%Al lowers the density of these steels by as much as 15%, unfortunately, this also results in large amounts of hard and faceted AlN …

Exploration For Alteration Halos Around The Ag-W Deposits In Southeastern Missouri, Usa, Daniel Joseph Warbritton

Masters Theses

"The St. Francois Mountains in SE Missouri are an extensive terrane of granitic ring complexes and associated rhyolites. They were an important source of Ag, W, and Sn and mined intermittently from the 1800s until the 1950s. The Ag-W ores occur in the Silvermine Granite and rhyolite roof rocks. The deposits are classified as a xenothermal ore system with mineralization occurring in quartz veins and surrounding greisen (up to 2.5 m). Exploration for hydrothermal ore deposits often focuses on the identification of alteration halos in the surrounding host rocks. In the vast majority of xenothermal ore deposits, such as in …

Near-Field Electrospinning Of A Polymer/Bioactive Glass Composite To Fabricate 3d Biomimetic Structures, Krishna C. R. Kolan, Jie Li, Sonya Roberts, Julie A. Semon, Jonghyun Park, D. E. Day, Ming-Chuan Leu

Biological Sciences Faculty Research & Creative Works

Bioactive glasses have recently gained attention in tissue engineering and three-dimensional (3D) bioprinting because of their ability to enhance angiogenesis. Some challenges for developing biological tissues with bioactive glasses include incorporation of glass particles and achieving a 3D architecture mimicking natural tissues. In this study, we investigate the fabrication of scaffolds with a polymer/bioactive glass composite using near-field electrospinning (NFES). An overall controlled 3D scaffold with pores, containing random fibers, is created and aimed to provide superior cell proliferation. Highly angiogenic borate bioactive glass (13-93B3) in 20 wt.% is added to polycaprolactone (PCL) to fabricate scaffolds using the NFES technique. …

Modeling Cell Line-Specific Recruitment Of Signaling Proteins To The Insulin-Like Growth Factor 1 Receptor, Keesha E. Erickson, Dipak Barua, For Full List Of Authors, See Publisher's Website.

Chemical and Biochemical Engineering Faculty Research & Creative Works

Receptor tyrosine kinases (RTKs) typically contain multiple autophosphorylation sites in their cytoplasmic domains. Once activated, these autophosphorylation sites can recruit downstream signaling proteins containing Src homology 2 (SH2) and phosphotyrosine-binding (PTB) domains, which recognize phosphotyrosine-containing short linear motifs (SLiMs). These domains and SLiMs have polyspecific or promiscuous binding activities. Thus, multiple signaling proteins may compete for binding to a common SLiM and vice versa. To investigate the effects of competition on RTK signaling, we used a rule-based modeling approach to develop and analyze models for ligand-induced recruitment of SH2/PTB domain-containing proteins to autophosphorylation sites in the insulin-like growth factor 1 …

Effects Of Mixing Methods Of Bifunctional Catalysts On Catalyst Stability Of Dme Synthesis Via Co₂ Hydrogenation, Shoujie Ren, Shiguang Li, Naomi Klinghoffer, Miao Yu, Xinhua Liang

Chemical and Biochemical Engineering Faculty Research & Creative Works

The effects of three different mixing methods of CuO/ZnO/Al₂O₃ (CZA) and HZSM-5 bifunctional catalyst on the stability for dimethyl ether (DME) synthesis from carbon dioxide (CO₂) hydrogenation were investigated. When the bifunctional catalyst was prepared by method A (mixing powder without pelletization), there was no significant change in DME production and catalyst stability when the HZSM-5 loading was varied between 0.1 g and 0.5 g with a fixed CZA loading of 0.5 g,. When the bifunctional catalysts were prepared by method B (pressed into pellets of CZA and pellets of HZSM-5 and then mixed) and …

Big Five Personality Traits In Learning Complex Information Systems: A Case Study, Bih-Ru Lea, Katherine Yu, Amanda Engelke, Carol Koob

Business and Information Technology Faculty Research & Creative Works

This research explores the influence of personality traits on the performance of learning a complex information system. The personality traits studied are conscientiousness, neuroticism, extraversion, openness, and agreeableness and the complex information system is represented by an Enterprise Resource Planning (ERP) System. The preliminary results indicate Openness, the interaction of Openness and Agreeableness, the interaction of Openness, Agreeableness, and Conscientiousness, the interaction of Openness, Agreeableness, and Extraversion, and the interaction Openness and Extraversion are statistically significant on influencing ERP learning performance.

Flavin Oxidation In Flavin-Dependent N-Monooxygenases, Reeder M. Robinson, Catherine A. Klancher, Pedro J. Rodriguez, Pablo Sobrado

Chemistry Faculty Research & Creative Works

Siderophore A (SidA) from Aspergillus fumigatus is a flavin-containing monooxygenase that hydroxylates ornithine (Orn) at the amino group of the side chain. Lysine (Lys) also binds to the active site of SidA; however, hydroxylation is not efficient and H₂O₂ is the main product. The effect of pH on steady-state kinetic parameters was measured and the results were consistent with Orn binding with the side chain amino group in the neutral form. From the pH dependence on flavin oxidation in the absence of Orn, a pKa value >9 was determined and assigned to the FAD-N5 atom. In the …

Dynamical Interference In The Vibronic Bond Breaking Reaction Of Hco, Shanyu Han, Xianfeng Zheng, Steve A. Ndengue, Yu Song, Richard Dawes, For Full List Of Authors, See Publisher's Website.

Chemistry Faculty Research & Creative Works

First-principles treatments of quantum molecular reaction dynamics have reached the level of quantitative accuracy even in cases with strong non-Born-Oppenheimer effects. This achievement permits the interpretation of puzzling experimental phenomena related to dynamics governed by multiple coupled potential energy surfaces. We present a combined experimental and theoretical study of the photodissociation of formyl radical (HCO). Oscillations observed in the distribution of product states are found to arise from the interference of matter waves-a manifestation analogous to Young's double-slit experiment.

Thermodynamic And Transport Properties Of Hydroxylammonium Nitrate-Based Electric Solid Propellant Vapor, Matthew S. Glascock, Patrick D. Drew, Joshua L. Rovey

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Electric solid propellants are advanced solid chemical rocket propellants controlled by electric current. Electric solid propellants may also be used in an electric propulsion system, specifically, an ablative pulsed plasma thruster. Previous experiments with the electric solid propellant HIPEP suggest its ablation processes are similar to traditional propellant polytetrafluoroethylene (C2F4). Better understanding of the ablation and resulting propulsion performance of HIPEP requires a model of its vapor composition and transport properties. This paper reports on the development of such a model. The model was validated by comparing results for C2F4 with literature, which showed agreement with multiple models described. Transport …

Influence Of A Backward-Facing Step On Swept-Wing Boundary-Layer Transition, Jenna L. Eppink, Richard W. Wlezien, Rudolph A. King, Meelan Choudhari

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Experimental measurements were performed on a swept flat-plate model with an airfoil leading edge and imposed chordwise pressure gradient to determine the effects of a backward-facing step on transition in a low-speed stationary crossflow-dominated boundary layer. Detailed hot-wire measurements were performed for three step heights ranging from 36 to 49% of the boundary-layer thickness at the step and corresponding to subcritical, nearly critical, and critical cases. In general, the step had a small, localized effect on the growth of the stationary crossflow vortex, whereas the unsteady disturbance amplitudes increased with increasing step height. Intermittent spikes in instantaneous velocity began to …

Corrigendum To ‘Zinc Oxide As An Active N-Layer And Antireflection Coating For Silicon Based Heterojunction Solar Cell’ [Sol. Energy Mater. Sol. Cells 139 (2015) 95–100](S0927024815001324)(10.1016/J.Solmat.2015.03.017), Babar Hussain, Abasifreke Ebong, Ian Ferguson

Electrical and Computer Engineering Faculty Research & Creative Works

The authors regret that permanent email address of the corresponding author is "[email protected]". The authors would like to apologize for any inconvenience caused.

Freeform Extrusion Fabrication Of Advanced Ceramics And Ceramic-Based Composites, Wenbin Li

Doctoral Dissertations

"Ceramic On-Demand Extrusion (CODE) is a recently developed freeform extrusion fabrication process for producing dense ceramic components from single and multiple constituents. In this process, aqueous paste of ceramic particles with a very low binder content ( < 1 vol%) is extruded through a moving nozzle to print each layer sequentially. Once one layer is printed, it is surrounded by oil to prevent undesirable water evaporation from the perimeters of the part. The oil level is regulated just below the topmost layer of the part being fabricated. Infrared radiation is then applied to uniformly and partially dry the top layer so that the yield stress of the paste increases to avoid part deformation. By repeating the above steps, the part is printed in a layer-wise fashion, followed by post-processing. Paste extrusion precision of different extrusion mechanisms was compared and analyzed, with an auger extruder determined to be the most suitable paste extruder for the CODE system. A novel fabrication system was developed based on a motion gantry, auger extruders, and peripheral devices. Sample specimens were then produced from 3 mol% yttria stabilized zirconia using this fabrication system, and their properties, including density, flexural strength, Young's modulus, Weibull modulus, fracture toughness, and hardness were measured. The results indicated that superior mechanical properties were achieved by the CODE process among all the additive manufacturing processes. Further development was made on the CODE process to fabricate ceramic components that have external/internal features such as overhangs by using fugitive support material. Finally, ceramic composites with functionally graded materials (FGMs) were fabricated by the CODE process using a dynamic mixing device"--Abstract, page iv.

Techno-Economic Optimization And Environmental Life Cycle Assessment Of Microgrids Using Genetic Algorithm And Artificial Neural Networks, Prashant Nagapurkar

Doctoral Dissertations

"This dissertation focuses primarily on techno-economic optimization and environmental life cycle assessment (LCA) of sustainable energy generation technologies. This work is divided into five papers. The first paper discusses the techno-economic optimization and environmental life cycle assessment of microgrids located in the USA using genetic algorithm. In this paper, a methodology was developed that assessed the techno-economic and environmental performance of a small scale microgrid located in US cities of Tucson, Lubbock and Dickinson. Providing uninterrupted power the microgrid was composed of seven components -- solar photovoltaics, wind-turbines, lead acid batteries, biodiesel generators, fuel cells, electrolyzers and H₂ tanks. …

High Level Thermochemical And Spectroscopic Computations For Molecules Relevant To Combustion And The Atmosphere, Bradley K. Welch

Doctoral Dissertations

"Computational thermochemistry can be a complicated multistep process, but in recent years has become an equal partner with experiment. Many important molecules in combustion systems or in the atmosphere (such as short-lived radicals) are difficult to study experimentally. Predicting highly accurate thermochemistry is a key aspect in understanding these species. In this project, computational thermochemistry was developed into an automated streamlined procedure and then used to understand the methyl and ethyl peroxy families of radicals. This effort involved optimizing a standard workflow for computational thermochemistry. Computational thermochemistry generally requires numerous individual calculations whose cost and scalings vary widely. Conducting such …

Microstructural Evolution Of Zirconium Carbide (Zrcₓ) Ceramics Under Irradiation Conditions, Raul Florez

Doctoral Dissertations

A comprehensive understanding of the microstructural evolution of Zirconium Carbide (ZrC₂) ceramics under irradiation conditions is required for their successful implementation in advanced Gen-IV gas-cooled nuclear reactors. The research presented in this dissertation focusses on elucidating the ion and electron irradiation response of ZrC₂ ceramics. In the first part of the research, the microstructural evolution was characterized for ZrC₂ ceramics irradiated with 10 MeV Au³⁺ ions up to doses of 30 displacement per atom (dpa) at 800 ºC. Coarsening of the defective microstructure, as a function of dose, was revealed by transmission electron microscopy analysis. …

The Benefit Of Precise Chemical Shift And Concentration Referencing In Nmr Applications, Ming Huang

Doctoral Dissertations

“In Nuclear Magnetic Resonance (NMR) spectroscopy, the chemical shift and intensity of NMR signals provide critical information about a sample's molecular structure, reaction conditions, and material properties. For the precise determination of structures and properties, it is critical to know sample or reaction conditions such as temperature, pH, concentration, or absolute amount of material. Chemical-shift and signal-intensity calibrations play a key role for extracting the maximum amount of information from NMR experiments. In this dissertation, internal and external reference standards are used to calibrate NMR spectra with respect to chemical shift and signal intensity. Sealed capillary tubes filled with specific …

Design And Prototyping Of A Real-Time Millimeter Wave Imaging System, Zahra Manzoor

Doctoral Dissertations

"The goal of this work is to design, prototype and test an innovative millimeter wave imaging system that operates in the frequency range of 33-35 GHz and is capable of producing rapid images of various diverse scenes. In particular, the imaging system includes two main sections, one is related to the hardware design of the system, and the other focuses on the development of a novel comprehensive image reconstruction algorithm. The hardware design includes custom transmitter and receiver sub-systems, and a sparse switched array which was optimized for 320 mm x 220 mm aperture plane, and also included an improved …

Wavelength-Selective Metamaterial Absorber And Emitter, Zhigang Li

Doctoral Dissertations

"Electromagnetic absorbers and emitters have been attracting interest in lots of fields, which are significantly revitalized because of the novel properties brought by the development of the metamaterials, the artificially designed materials. Metamaterials broadens the approaches to design the electromagnetic absorbers and emitters, making it possible to obtain the perfect absorption or emission at the wavelengths covering a wide range. Metamaterial absorbers and emitters are promising for various applications, including solar thermal-photovoltaics and thermal-photovoltaics for energy harvesting, chemical and biomedical sensors, nanoscale imaging and color printing. This work focuses on three aspects (materials, structures and design methods) to improve the …

Deep Neural Network Learning-Based Classifier Design For Big-Data Analytics, Krishnan Raghavan

Doctoral Dissertations

"In this digital age, big-data sets are commonly found in the field of healthcare, manufacturing and others where sustainable analysis is necessary to create useful information. Big-data sets are often characterized by high-dimensionality and massive sample size. High dimensionality refers to the presence of unwanted dimensions in the data where challenges such as noise, spurious correlation and incidental endogeneity are observed. Massive sample size, on the other hand, introduces the problem of heterogeneity because complex and unstructured data types must analyzed. To mitigate the impact of these challenges while considering the application of classification, a two step analysis approach is …

Fault Imaging Enhancement In Taranaki Basin, New Zealand And Rock Physics And Inversion Based Reservoir Characterization In The Central Gulf Coast Region Of Texas, Tianze Zhang

Doctoral Dissertations

"Fault imaging technique and reservoir characterization based on rock physics analysis and pre-stack inversion has been widely used hydrocarbon exploration. For the fault imaging technique, the ant tracking has been widely used in fault interpretation. However, the reliability of the results is highly dependent on appropriately choosing a signal processing method and volume attributes. In our study area, which lies in the southern Taranaki Basin, we applied Graphic Equalizer as the processing tool and the Chaos attribute before running the ant tracking algorithm. Results show that the procedure provides a better result and can map both the major and minor …

Coherent Effects In Wave Propagation Through Complex Media, Milan Koirala

Doctoral Dissertations

"Diffusion is a powerful and versatile description of a typical wave propagation in a random scattering medium that disregards phase and, thus, a possibility of interference. Speckle, transmission fluctuations, wave localization, non-local correlations, and transmission eigenchannels are examples of persistent interference effects, which arise in the course of deterministic propagation. Such wave phenomena contain a wealth of information about the medium and the source of waves, enabling sensing and coherent control of the propagation. The nonlocal correlations and speckle statistics of the partially coherent light are used to uncover an object hidden by a diffusive cloak inside a strong scattering …

Insights Into Well Performance And Completion Optimization Using A Coupled Fracfocus And Drillinginfo Database, Mustafa A. Al-Alwani

Doctoral Dissertations

“The hydraulic fracturing designs, drilling, and completion trends are undergoing continuous change as the oil and gas industry pushing the boundaries of the traditional designs to increase wells productivity and meet the energy demand. The lateral length in addition to the amount of proppant and water used in well stimulation have witnessed a paradigm shift over the past few years. The motivation for this work began with a desire to better understand well performance as a function of the type of fracturing fluid treatment applied. An early objective was to compare whether East Texas Cotton Valley wells stimulated with water …

Designing Novel Multinary Transition Metal Selenides As High-Efficiency Oxygen Evolution Reaction Electrocatalysts And Investigating Surface Properties, Xi Cao

Doctoral Dissertations

”Water splitting has been widely considered to be an efficient way to generate sustainable and renewable energy resources in fuel cells, metal-air batteries and other energy conversion devices. Exploring efficient electrocatalysts to expedite the anodic oxygen evolution reaction (OER) is a crucial task that needs to be addressed to boost the practical application of water splitting. This research focuses on the identification of OER electrocatalysts by systematically designing non-stochiometric mixed transition metal-based selenide OER electrocatalysts through combinatorial electrodeposition and investigation of selenide-based naturally occurring minerals as effective OER electrocatalyst. Paper I describes the study of Ni-Fe-Co selenides as OER catalysts …