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Manganese Catalysis In The Activation Of Si-H And B-H Bonds And Synthesis Of Degradable Poly(Silylether)S From Renewable Resources, Srikanth Vijjamarri

Theses and Dissertations

In recent years, significant efforts have been made regarding the development and synthesis of degradable and thermally stable polymers from renewable feedstock due to the sustainability concerns caused by petroleum-based chemicals and materials. The present dissertation describes the synthesis, structural studies, degradation, and thermal stabilities of various poly(silylether)s prepared from biomass-based chemicals.

An air-stable manganese salen nitrido complex [MnVN(salen-3,5-tBu2)] (Mn-1) was found to be an effective catalyst for the synthesis of poly(silylether)s via dehydrogenative coupling and hydrosilylation reactions. The catalytic activity of the manganese catalyst was initially examined in the protection of hydroxyl and carboxylic groups of alcohols and carboxylic …

Modeling And Improving Oxygen Carrier Performance In Chemical Looping Combustion Systems, Johannes George Van Der Watt

Theses and Dissertations

Countries across the world have different expectations on carbon dioxide (CO2) capturing and the willingness to commit to international agreements continually change. At present, the CO2 capture market is weak as industries are reluctant to take up the costs and risks associated with implementing the capture technologies. Globally, and in the United States of America (U.S.A.) in particular, the perception is that emerging energy technologies with carbon capture are too expensive or inefficient to attract investors without government backing and subsidies. Coal usage has accordingly declined. By expanding the coal value chain into more than just electricity generation, it can …

Digital Image Processing And Metabolic Parameter Linearity To Noninvasively Detect Analyte Concentration, Joseph Allen Jr

Theses and Dissertations

Spectroscopy is the scientific technique of quantifying and measuring electromagnetic, or light, reflectance or absorption. Atoms emit and/or absorb light when light passes through. The excitations provide specific energy signatures that relate to the element that is emitting or absorbing the light. Non-invasive biosensors monitor physical health properties such as heart rate, oxygen saturation, and tissue blood flow as a result of spectroscopy. Several attempts have been made to non-invasively detect metabolic chemical, or analyte, concentration with various spectroscopic techniques. The primary limitation is due to signal-to-noise ratio. This research focuses on a unique method that combines emission spectroscopy and …

Hysteretic Behavior Of Thin-Walled Steel Tubular Columns Under Constant Axial Force And Cyclic Lateral Loading, Qusay A. Al-Kaseasbeh

Theses and Dissertations

Thin-walled steel tubular bridge piers (column refers to “bridge pier” in the subsequent text) with either circular and square box cross sections are becoming an increasingly attractive choice as cantilever bridge piers in severe earthquake regions due to their architectural, structural and constructional advantages. However, thin-walled steel tubular columns are vulnerable to local buckling, global buckling or interaction between both under extreme loading events such as strong earthquakes. This buckling results in a significant strength and ductility degradation, which eventually leads to an early and full collapse of the thin-walled steel tubular columns. The work presented in this dissertation investigates …

Small-Scale Characterization Of Additively Manufactured And Heat Treated Alsi10mg, Farwan A. Alghamdi

Theses and Dissertations

Selective Laser Melting (SLM) additive manufacturing of aluminum alloys is a layer-wise manufacturing method which can provide lightweight and complex-in-shape automotive, aerospace and medical components with enhanced mechanical properties. In the SLM, the mechanical properties will differentiate depending on the cooling rate as the deposition of material gradation distance from the build plate as well as the deposition direction, in which it has an effect on the microstructure.

The aim of this project is to assess the correlation between microstructure and small-scale characteristics of an additive manufactured AlSi10Mg alloy in the as-printed and heat treated conditions. Post heat treatment cycle …

Extraction And Purification Of Humic Acid From Leonardite As A Graphene Precursor For Lithium Ion Battery Cathodes, Justin James Baker

Theses and Dissertations

Lithium ion batteries present a promising solution for energy storage applications which can be utilized to make green energy generation from sources such as wind and solar more practical. Lithium iron phosphate is an attractive battery cathode material due to its long lifespan, safety and stability, and environmentally friendly chemistry. One shortcoming of lithium iron phosphate is its inherently low conductivity, which is commonly overcome through the addition of conductive carbon. Graphene is a two-dimensional nanomaterial comprised of a single layer of carbon atoms, which displays excellent electrical, thermal, and mechanical properties. Commercial incorporation of graphene into battery electrode materials …

Synthesis And Characterization Of Quasi-Two-Dimensional Chromium Sulfides, Furkan Muhammet Altincicek

Theses and Dissertations

Transition metal dichalcogenides (TMDs) are atomically thin semiconductors of the type MX2 with M being a transition metal and X being a chalcogen atom. TMDs have recently attracted considerable attention because of their novel electronic and optical properties. Many TMDs have been studied except CrS2 because of the challenges in its synthesis. However, the most stable form of chromium sulfides, Cr2S3, chromium (III) sulfide, has been known to exhibit novel properties. For this reason, we studied the possibility of synthesizing thin Cr2S3 to mimic CrS2. We synthesized single phase Cr2S3 in vacuum sealed quartz tubes. The synthesis takes about 5 …

Determination Of Maximum Scour Depth For Spur Dikes Based On A Validated Two-Dimensional Hec-Ras Model, Mathew Lee Cox

Theses and Dissertations

The introduction of spur dikes into a river flow field can have many far-reaching positive effects on the stability of a river channel. While the flow velocity directly at the spur dike tip or crest may increase, a large embayment area downstream of the spur dike will form with reduced flow velocities. Due to the increase in flow velocity at the spur dike, a scour hole will form. Scour is the leading cause of failure of hydraulic structures. In the past many hydraulic structures were tested by building scale prototype models, this method is very costly and hard to model …

Thermomechanical Processing Of Mg-Li-Al Ultralight Alloys, Rezawana Islam

Theses and Dissertations

Globally, magnesium (Mg), as the lightest metallic material, imparts a significant long term impact on the stipulation of lightweight structures in aerospace and automotive industries. However, the deformation behavior of magnesium at ambient (room) temperature is not acceptable for most of the structural applications because of its hexagonal closed pack (hcp) structure and limited active slip systems which result in an unacceptable level of brittleness (literally no formability at ambient temperature). Having said this, alloying Mg with an element with more active slip system in its crystalline structure (i.e. lithium with body center cubic crystalline structure) might be a solution …

Per- And Polyfluoroalkyl Substances In The Soil Environment: Sorption, Bioaccumulation And Biotransformation, Bosen Jin

Theses and Dissertations

Per- and polyfluoroalkyl substances (PFASs) are man-made chemicals, widely used in both industries and daily lives, such as in non-stick cookware, waterproof clothing, and painting materials. Researchers have investigated PFASs for about two decades, but most of the studies focus on perfluoroalkyl substances with very limited information available on polyfluoroalkyl substances. In this research, we investigated the sorption/desorption mechanisms perfluorooctanoic acid (PFOA) and its two cationic and zwitterionic precursor compounds, perfluorooctanesulfonamido ammonium salt (PFOSAmS) and perfluorooctaneamido betaine (PFOAB) in a group of soil. We also studied the bioaccumulation and bioconcentration of these chemicals along with perfluorooctane sulfonate (PFOS) and its …

Earthquake Loading Effects On The Buckling Of Liquid Filled Cylindrical Storage Tanks, Hailey Johnson

Theses and Dissertations

This thesis studied twelve liquid filled cylindrical storage tanks to determine the static buckling loads, as well as the dynamic buckling loads when subjected to earthquake loading. The geometries of the cylindrical tanks were investigated with height-to-diameter ratios of 0.5, 0.75, 1.0, 1.25, 1.5, and 2.0 and with diameter-to-thickness ratios of 520.83 and 1,041.67. Each cylindrical tank modeled had a constant thickness of 0.36 inches. ANSYS Workbench was used to create a finite element analysis of each cylindrical tank. A transient dynamic bucking analysis was performed on each model in order to determine the dynamic buckling load of the cylindrical …

Antennas And Wave Propagation In Wireless Body Area Networks: Design And Evaluation Techniques, Ala Alemaryeen

Theses and Dissertations

Recently, fabrication of miniature electronic devices that can be used for wireless connectivity becomes of great interest in many applications. This has resulted in many small and compact wireless devices that are either implantable or wearable. As these devices are small, the space for the antenna is limited. An antenna is the part of the wireless device that receives and transmits a wireless signal. Implantable and wearable antennas are very susceptible to harmful performance degradation caused by the human body and very difficult to integrate, if not designed properly. A designer need to minimize unwanted radiation absorption by the human …

Characteristics Of Convectively Induced Turbulence Determined From Tropical And Midlatitude Simulations, Katelyn Audrey Barber

Theses and Dissertations

Out-of-cloud convectively induced turbulence (CIT) poses both a serious threat to aviation operations and a challenge to forecasting applications. This challenge is particularly large in the tropics, as CIT prediction and avoidance are limited due to sparse observations and lack of tropical turbulence research. This study uses high resolution numerical simulations to investigate out-of-cloud CIT properties including intensity, areal coverage, and location using popular turbulence diagnostics in both the tropics and midlatitudes. Convective types are varied in both regions to determine the influence of convective strength and stage (developing versus mature) on CIT characteristics. The Ellrod index, Richardson number, subgrid-scale …

Characterizing The Contribution Of Groudwater In The Water Budgets Of Wetlands Using Gis Groundwater Modeling And The Field Measurement Of Water Quality, Brianna Fuller Speldrich

Theses and Dissertations

Wetlands provide many benefits to society, including flood attenuation, groundwater recharge, water quality improvement, and habitat for wildlife. Because their structure and function are sensitive to changes in hydrology, characterizing the water budgets of wetlands is crucial to effective management and conservation. The groundwater component of a budget, which often controls resiliency and water quality, is particularly difficult to estimate and can be costly, time-consuming, and invasive. This study used a GIS approach using a digital elevation model (DEM) and the elevations of lakes, wetlands, streams, and hydric soils to produce a water-table surface raster for a portion of the …

Evolution Of Object-Oriented Methods From The Reverse Engineering Of Programming Code, Pann Ajjimaporn

Theses and Dissertations

Many software development projects fail because of their inability to deliver the product in a timely and cost-effective manner, i.e. the software crisis. In a commercial airline company, a safety-critical system for preventing a “single-point of failure” needs to be developed and certified. To meet the project deadline an Agile approach was used in developing the first portion of the system. An appropriate software development methodology, i.e. reverse-engineering was then applied to the software system to develop method that would be used in system maintenance and evaluation.

The goals of this research study were to develop a segment of one …

The Effect Of Different Dianhydride Precursors On The Synthesis, Characterization And Gas Separation Properties Of Pi And Pbo Derived From Bisapaf, Maram Abdulhakim Qasem Al-Sayaghi

Theses and Dissertations

The current processes used for natural gas separation and purification are considered energy intensive which could potentially be substituted by membrane technology. Aromatic polyimides are considered one of the most viable types of polymers used for the fabrication of membranes for gas separation mainly due to their outstanding properties. Moreover, aromatic polyimides could be thermally rearranged to form another class of polymers called polybenzoxazoles which are characterized by having enhanced gas separation properties. This research aimed to (1) synthesize and characterize three different aromatic polyimides via polycondensation reaction of a diamine (BisAPAF) with three different dianhydride precursors (PMDA, ODPA, BTDA), …

Impacts Of Cold Region Hydroclimatic Variability On Phosphorus Exports: Insights From Concentrations - Discharge Relationships, Tyson Lee Jeannotte

Theses and Dissertations

In Devils Lake ND, a terminal lake in the Northern Great Plains, algae blooms are of great concern due to the recent increase of streamflow and subsequent elevated concentrations of nutrients, particularly phosphorus. To date, very few studies explore P concentration to streamflow relationship in cold region agricultural basins, specially the headwater catchments of the Devils Lake basin. This study gains a better understanding of the impacts of hydroclimatic variation on concentration to streamflow relationships between two headwater catchments (Mauvais Coulee: 1032 km2 and Tributary 3: 160 km2) draining to Devils Lake during the 2016-2018 period. This study presents high-resolution …

Chromium Selenide Synthesis And Characterization, Alexander Kukay

Theses and Dissertations

A number of transition metal chalcogenides have displayed promising electrical and magnetic properties that may prove to be ideal materials for various electro-chemical applications. However, production of various transition metal chalcogenides has remains unique to each material and typically these synthesis techniques are not scalable for industrial utilization. Using a generalized heat treatment, various chromium selenium compounds were synthesized. Phase control has been demonstrated by restricting the amount of oxygen present in the reaction vessel. Obtaining different phases as a result of changing an environmental condition suggests a tunable reaction method that can be used to synthesize a number of …

United States Coast Guard Aviation Safety: Relationship Between The Safety Survey And The Extent Of Hazard Reporting, James Cooley

Theses and Dissertations

Aviation safety outcomes, such as mishaps, are a product of an aviation organization’s safety culture (Reason, 2008; Reiman & Pietikäinen, 2012). Safety cultures should be assessed in order to improve an organization’s state of safety (Adjekum et al., 2015; Cooper, Collins, Bernard, Schwann, & Knox, 2019; Wiegmann, Zhang, von Thaden, Sharma, & Gibbons, 2004). Questionnaires are one of the best ways of obtaining information about an organization’s safety culture (Wiegmann et al., 2004; Wald, Gray, & Eatough, 2018). Additionally, the extent to which aviation hazards are reported (hazreps) serve as an indicator of the health of an aviation Safety Management …

Exploring K-12 Superintendent Turnover: Career Advancement Or Dissatisfaction Realized?, Francis Arthur Schill

Theses and Dissertations

Leading educational reform is one of a superintendent’s many roles, which involves working with elected school board members with varying beliefs of what constitutes educational reform. Superintendents accept this responsibility despite the considerable challenge that meaningful educational reform efforts take at least five years (Fullan & Stiegelbauer, 1991). The average stay of a superintendent in a school district is six and a half years, further complicating reform efforts (Glass & Franceschini, 2007). The purpose of the study was to better understand the factors that lead to the turnover of superintendents of K-12 schools in North Dakota.

The conceptual framework for …

Evaluation Of Co2 Flooding In Tight Formation, Sai Wang

Theses and Dissertations

The low recovery of oil from the tight liquid-rich formations is still a main challenge for the tight reservoir. Thus, in order to break the chains and remove the obstacle such as the low recovery factor in the Bakken tight formation, even though the horizontal drilling and hydraulic fracturing technologies were already well applied in this field, the supercritical CO2 flooding was proposed as an immense potential recovery method for the production improvement.

In this research, we conducted a series of CO2 flooding experiments under various injection pressure (2500psi, 2800psi, 3000psi, 3500psi), to investigate the recovery potential of the core …

Nmr Characterization And Chemical Enhanced Oil Recovery Using Surfactants In Unconventional Reservoirs, Mohamed Mohamed Awad Mohamed

Theses and Dissertations

The main goal in this research is characterization of the Bakken and Three Forks formations using NMR and conduct phase behavior tests to find a formulation suitable for spontaneous imbibition test for Middle Bakken core samples under the Bakken reservoir temperature and brine salinity.

NMR measurements were performed for as-received twin core samples from the Upper Bakken, Middle Bakken and Three Forks formation and after saturation with Bakken formation brine and octane. The measurements were conducted using 2.3 MHz and 22 MHz Larmor frequencies. The measurements also conducted at 25° and 100°C using 2.3 MHz Larmor frequency only. EOR potential …

Volume 56, Number 19: December 19, 2018, University Of North Dakota

University Letter Archive

No abstract provided.

Winter Commencement: December 13-14, 2018, University Of North Dakota

UND Commencement Programs

UND Winter Commencement program from December 13-14, 2018.

Volume 56, Number 18: December 12, 2018, University Of North Dakota

University Letter Archive

No abstract provided.

Concentric Contra-Rotating Dual Shaft Vertical Axis Wind Turbine, Emily Walz, Marcellin Zahui, Andrew Shires, Carl Gilkeson

Essential Studies UNDergraduate Showcase

A typical vertical axis wind turbine (VAWT) consists of two or more airfoils all attached to a single central axis. The wind turbine style most commonly found in renewable energy is the horizontal axis wind turbine (HAWT) that have a high energy production efficiency in exchange for requiring large amounts of land and air space. Alternatively, a VAWT can function in low speeds and in smaller less typical locations. As a result, novel VAWT designs are researched to improve their energy efficiency. An example of a novel VAWT is the concentric counter-rotating VAWT investigated theoretically using the 2D computational fluid …

Carbohydrate Extraction From The Chorella Vulgaris Microalgae Strain, William Hammann, Wayne Seames, Andrew Ross

Essential Studies UNDergraduate Showcase

The cultivation and exploitation of microalgae biomass as a source of renewable fuels and other chemicals has been an active area of research due to microalgae’s high productivity and the relatively high concentrations of valuable intracellular components, like lipids (fatty acid-based oils), proteins, and polysaccharides. Commercialization of this technology will help mitigate global climate change by reducing fossil-derived products by producing analog renewable fuels and chemicals. Traditionally, the main focus of microalgae-based fuels/chemicals research and development has been on the lipids that many strains generate, but current research shows that solely recovering the oils may not be cost competitive with …

Volume 56, Number 17: December 05, 2018, University Of North Dakota

University Letter Archive

No abstract provided.

Exploring Large Pore Size Alumina And Silica-Alumina Based Catalysts For Decomposition Of Lignin, Sara Pourjafar, Jasmine Kreft, Honza Bilek, Evguenii Kozliak, Wayne Seames

Chemical Engineering Faculty Publications

Evaluation of copper doped silica-alumina and γ-alumina catalysts for lignin decomposition was conducted using a suite of chemical analysis protocols that enabled a comprehensive characterization of the reaction product. X-ray diffraction analysis was used to verify the concentration of doped copper on catalyst supports. Then, batch experiments were performed to study the significance of catalyst support type, catalyst dopant concentration, lignin concentration, catalyst-to-lignin ratio, reactor stirring rate and reaction time. Aqueous products were extracted with dichloromethane and analyzed using a detailed gas chromatography-mass spectrophotometry analytical protocol, allowing for quantification of over 20 compounds. Solid residues were analyzed by thermogravimetric analysis …

Impact Of Radiative Losses On Flame Acceleration And Deflagration To Detonation Transition Of Lean Hydrogen-Air Mixtures In A Macro-Channel With Obstacles, Gautham Krishnamoorthy, Lucky Nteke Mulenga

Chemical Engineering Faculty Publications

While there has been some recognition regarding the impact of thermal boundary conditions (adiabatic versus isothermal) on premixed flame propagation mechanisms in micro-channels (hydraulic diameters <10 mm), their impact in macro-channels has often been overlooked due to small surface-area-to-volume ratios of the propagating combustion wave. Further, the impact of radiative losses has also been neglected due to its anticipated insignificance based on scaling analysis and the high computational cost associated with resolving it’s spatial, temporal, directional, and wavelength dependencies. However, when channel conditions promote flame acceleration and deflagration-to-detonation transitions (DDT), large pressures are encountered in the vicinity of the combustion wave, thereby increasing the magnitude of radiative losses which in turn can impact the strength and velocity of the combustion wave. This is demonstrated for the first time through simulations of lean (equivalence ratio: 0.5) hydrogen-air mixtures in a macro-channel (hydraulic diameter: 174 mm) with obstacles (Blockage ratio: 0.51). By employing Planck mean absorption coefficients in conjunction with the P-1 radiation model, radiative losses are shown to affect the run-up distances to DDT in a long channel (length: 11.878 m). As anticipated, the differences in run-up distances resulting from radiative losses only increased with system pressure.