Digital Commons Network^™

Wireless Power Transfer In Autonomous Mobile Microgrids, Carl Greene

Dissertations, Master's Theses and Master's Reports

The ability to autonomously dock unmanned ground vehicles plays a key role in mobile micro-grids, where efficient power transfer is paramount. The approach utilized in this work allows for near-field wireless power transfer in remote locations with minimal support. Establishing a micro-grid power system connection autonomously using wireless power eliminates the arduous task of designing a complex, multiple degrees of freedom (MDOF) robotic arm. The work presented in this thesis focuses on both the hardware and software within the micro-grid system. This particular near-field wireless system consists of a primary and secondary set of modules, comprised of Litz wire coils, …

Passivity-Based Numerical Modeling And Grid Integration Strategies For Wave Energy Converter Arrays, Salman Husain

Dissertations, Master's Theses and Master's Reports

The body of work presented here develops numerical time-domain models of Wave Energy Converter (WEC) arrays or wave farms. It will be shown here that a cluster of WECs can be more effective in extracting oceanic energy, can facilitate deployment logistics, and help with grid integration. The objectives of this work are: (i) developing a theoretical metric to evaluate the energy extraction potential of a WEC array, (ii) developing an algorithm that ensures the stability of the time-domain models of WEC arrays, and (iii) identifying strategies that facilitate grid integration and power management of a WEC array. In the process …

An Experimental Study Of Fuel Selection For A Gasoline Multi-Mode, Spark Ignited – Compression Ignition Engine, Zachary J. Stanchina

Dissertations, Master's Theses and Master's Reports

In this study of fuels of different reactivities and their performance in a low-temperature combustion (LTC) engine. The engine was a 2.2L CRDI engine code D4HB provided by industry partner Hyundai America Technical Center inc. (HATCI). The engine was instrumented with in-cylinder pressure sensors allowing for monitoring of the combustion process.

First, the engine was operated with standard US pump grade gasoline, Research Octane number (RON) 91 E10, to find initial operation conditions as well as control points of stable operation for daily checks on system conditions.

Tested were 8 different fuel blends, the four base blends were provided by …

Water Woes Worsen: Middle Rio Grande Reservoir Modeling Projects Declining Water Availability Under Climate Change Simulations, Robyn Holmes

Dissertations, Master's Theses and Master's Reports

The Middle Rio Grande is a vital source of water for over 2M people. Climate change is impacting regional hydrology and is likely to put additional stress on a water supply that is already stretched thin. To gain insight on future water availability, a simple water balance model was used to simulate the Elephant Butte-Caballo reservoir system (Southern New Mexico, USA). The water balance model was run under 97 climate simulations derived from Global Climate Models (GCMs) developed under the Intergovernmental Panel on Climate Change's (IPCC) 5^th generation Coupled Modeling Intercomparison Project (CMIP5). Results suggest that the percentage of …

Per- And Polyfluoroalkyl Substances Mitigation From Contaminated Groundwater Using Halophyte And Cow Bone Biochars, Bailey Papes

Dissertations, Master's Theses and Master's Reports

Per- and polyfluoroalkyl substances (PFAS) groundwater contamination is a growing concern for the Brackish Groundwater National Desalination Research Facility. Two of the four wells onsite are contaminated with perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), and perfluorohexane sulfonic acid (PFHxS). The removal of PFAS by adsorption onto powder activated carbon (PAC) is promising, but the production of PAC is energy intensive and expensive. A potential cost-effective alternative to PAC is biochar. This study quantified the capacities of two halophyte biochars, cow bone biochar and PAC to adsorb PFOA, PFOS, and PFHxS from brackish groundwater. The three biochars were ineffective at …

Microscale Transverse Compression Modeling: A Comparative Study Of The Analytical Mac/Gmc Methods To Experimental Results, Emily Zeitunian

Dissertations, Master's Theses and Master's Reports

Composite materials require a multi-scale approach to fully understand its behavior. At the micro level, material behavior analysis is conducted most often using numerical or analytical approaches. These models, however, require validation from experimental data to ensure material predictions are accurate. This study compares a semi-analytical micromechanical analysis tool, MAC/GMC, to experimental results of in-situ microscale transverse compression testing conducted at AFRL facilities. Effective properties, stress-strain curves, stress and strain fields, and damage predictions are compared with experimental outputs. Both generalized method of cells (GMC) and high-fidelity generalized method of cells (HFGMC) theories implemented within MAC/GMC show results that agree …

Development And Validation Of A Force Measuring Device For A Laboratory Wave Tank, Jacob K. Colling

Dissertations, Master's Theses and Master's Reports

The ability to predict the hydrodynamic force exerted on floating bodies plays a critical role in creating more effective control strategies for wave energy converters (WECs). Developing a test apparatus capable of directly measuring the forces exerted on a floating body subjected to a wavefield provides the means to validate theoretical prediction methods with experimental results and to develop data-based prediction methods for hydrodynamic forces. This report will discuss the development and validation of a device that measures the total vertical force exerted on a test artifact. The device requirements and design are discussed to examine the factors taken into …

Development Of Advanced Models For Pre-Ignition Prediction In Gas Engines And Analytical Model For Wallfilm Evaporation, Ankith Ullal

Dissertations, Master's Theses and Master's Reports

Ever-changing regulations aimed at improving efficiency and reducing harmful emissions have resulted in many power-generation device (engine) manufacturers to adopt new strategies. Computer simulation of these new strategies of power generation requires more accurate and higher fidelity modelling tools. In the present study, two such models are developed. The first model deals with pre-ignition phenomena driven by lubricant (lube) oil in natural gas engines and the second model is relevant to prediction of wallfilm evaporation by employing analytical solutions to transport governing equations for boundary layers.

Pre-ignition in engines has been the subject of current research with the advent of …

Optimal Control Of Nonlinear Wave Energy Converters In Heave For Maximum Power Extraction, Kevin Nelson

Dissertations, Master's Theses and Master's Reports

The marine renewable energy community is interested in maximizing the power generated by nonlinear wave energy converters. Optimal control methods provide a tool to achieve this aim and can also help to inform the buoy design. An energy-optimal control law for a class of non-linear buoy models is derived and is shown to be singular. The solution approach is illustrated using an hourglass-shaped buoy having a cubic, hydrostatic nonlinearity. The optimal control law is only valid on singular arcs, and a method to search for these arcs is presented. Two singular arcs are found for the hourglass buoy model and …

Molecular Modeling Of High-Performance Thermoset Polymer Matrix Composites For Aerospace Applications, Prathamesh P. Deshpande

Dissertations, Master's Theses and Master's Reports

The global efforts from major space agencies to transport humans to Mars will require a novel lightweight and ultra-high strength material for the spacecraft structure. Three decades of research with the carbon nanotubes (CNTs) have proved that the material can be an ideal candidate for the composite reinforcement if certain shortcomings are overcome. Also, the rapid development of the polymer resin industry has introduced a wide range of high-performance resins that show high compatibility with the graphitic surface of the CNTs. This research explores the computational design of these materials and evaluates their efficacy as the next generation of aerospace …

A Combined Spectral And Energy Morphology Analysis Of Gamma Ray Source Hawc J2031+415 In The Cygnus Constellation, Ian Herzog

Dissertations, Master's Theses and Master's Reports

HAWC J2031+415 is a probable pulsar wind nebula (PWN) located in the Cygnus Cocoon region near a complex OB star cluster. First observed by the High-Energy-Gamma-Ray Astronomy (HEGRA) observatory in the TeV energy regime, the source had no apparent counterpart in lower energy ranges. Previous work using 1343 days of data from the High-Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory has determined that three sources are present in the Region of Interest (ROI): HAWC J2031+415, HAWC J2030+409 (also known as the Cocoon), and 3HWC J2020+403 (associated with the Gamma Cygni supernova remnant) \cite{Ian_01, Binita_01}.

In this work, I use the newest …

Atomistic-Continuum Membrane And Machine Learning Models For Two-Dimensional Materials, Upenda Yadav

Dissertations, Master's Theses and Master's Reports

“What could we do with layered structures with just the right layers?” asked Richard Feynman in his famous 1959 lecture, “There’s plenty of room at the bottom.” With the help of the amazing developments of the past several years, we are coming close to answering that question. In 2004, graphene was first isolated from graphite and only six short years later it won the Nobel Prize in Physics. Graphene is one atomic layer of Carbon, it is the thinnest and yet the strongest materials we have ever seen. It is 200 times stronger than its equivalent weight in steel and …

Design And Analysis Of Marangoni-Driven Robotic Surfers, Mitchel L. Timm

Dissertations, Master's Theses and Master's Reports

We designed and experimentally studied the dynamics of two robotic systems that surf along the water-air interface. The robots were self-propelled by means of creating and maintaining a surface tension gradient resulting from an asymmetric release of isopropyl alcohol (IPA). The imbalance in the distribution of surface tension surrounding the robots generates a propulsive force commonly referred to as Marangoni propulsion. First, we considered a single surfer, which was custom-made with novel control mechanisms that allow for both forward motion and steering to be remotely adjusted solely through the manipulation of local surface stresses. We analyzed the performance of this …

Collective Hydrodynamics Of Robotic Fish, Rohit S. Pandhare

Dissertations, Master's Theses and Master's Reports

Many animals in nature travel in groups either for protection, survival, or endurance. Among these, fish do so under the burden of hydrodynamic loads, which incites questions as to the significance of the multi-body fluid-mediated interactions that facilitate collective swimming. We study such interactions in the idealized setting of a rotational array of robotic fish whose tails undergo a prescribed flapping motion, but whose swimming speed is determined as a natural result of the hydrodynamic effects. Specifically, we examine how the measured collective speed of the swimmers varies with the imposed frequency and amplitude of their tail flapping, and with …

Trophic Ecology And Mercury Bioaccumulation Among Lake Superior Lake Trout Ecotypes, Dalton C. Norris

Dissertations, Master's Theses and Master's Reports

The Lake Superior lake trout population consists of siscowet, lean, humper and redfin ecological morphotypes or ‘ecotypes’. In addition to morphological differences, these ecotypes occupy different habitats in Lake Superior and partition various invertebrate and fish prey resources. In this study, I measured the stable isotopes of carbon (δ¹³C) and nitrogen (δ¹⁵N) and mercury concentrations among these ecotypes collected from Lake Superior waters surrounding Isle Royale. Average mercury concentrations were highest for redfins (1389 ng/g dry wt) followed by siscowets (823 ng/g), humpers (799 ng/g) and leans (519 ng/g) and differed significantly among the ecotypes ( …

Concept Evaluation And Development Of A Novel Approach For Integration Of Turbogeneration, Electrification And Supercharging On Heavy Duty Engines, Satyum Joshi

Dissertations, Master's Theses and Master's Reports

While many technologies such as electrically assisted turbocharging, exhaust energy recovery and mild hybridization have already proven to significantly increase heavy-duty engine efficiency, the key challenge to their widespread adoption has been their cost effectiveness and packaging. This research specifically addresses these challenges through evaluation and development of a novel technology concept termed as the Integrated Turbogeneration, Electrification and Supercharging (ITES) system. The concept integrates a secondary compressor, a turbocompound/expander turbine and an electric motor through a planetary gearset into the engine cranktrain. The approach enables a reduced system cost and space-claim, while maximizing the efficiency benefits of independent technologies. …

Length-Scale-Dependent Stress Relief Mechanisms In High Purity Indium, Fereshteh Mallakpour

Dissertations, Master's Theses and Master's Reports

Lithium-ion batteries are widely used in portable electronics and electric vehicles. However, due to the presence of flammable liquid electrolytes, these devices fail catastrophically when the cell experiences a short circuit. One attractive solution to this problem is a solid-state battery. As the name implies, the flammable liquid electrolyte is replaced by a non-flammable solid-state electrolyte (SSE). The unexpected, yet frequently observed failure mechanism in these devices is the formation and growth of lithium dendrites originating at the interface between the lithium anode and the SSE. As the dendrites grow, device performance degrades. Once the dendrites completely penetrate the SSE, …

An Experimental Study On The Impact Of Water Injection On The Performance And Emissions Of A Natural Gas – Diesel Pilot Engine, Nic Tuma

Dissertations, Master's Theses and Master's Reports

Natural gas has been gaining popularity as an alternative fuel due to its high availability, low CO2 emissions, and low cost. In this experimental study, water injection’s impact on medium and heavy-duty engine operation fueled by natural gas and pilot diesel injection for ignition was studied under stochiometric operation for use with a three-way catalytic converter to meet criteria emissions for off-road power generation. To retain high efficiencies, a high compression ratio of 17.3:1 was used. Maintaining stoichiometric operation with a high compression ratio leads to combustion knock, pre-ignition, and high NOx formation. Conventionally, cooled EGR can be used to …

Model Predictive Control Of Energy Systems For Heat And Power Applications, Chethan Ramakrishna Reddy

Dissertations, Master's Theses and Master's Reports

Building and transportation sectors together account for two-thirds of the total energy consumption in the US. There is a need to make these energy systems (i.e., buildings and vehicles) more energy efficient. One way to make grid-connected buildings more energy efficient is to integrate the heating, ventilation and air conditioning (HVAC) system of the building with a micro-scale concentrated solar power (MicroCSP) sys- tem. Additionally, one way to make vehicles driven by internal combustion engine (ICE) more energy efficient is by integrating the ICE with a waste heat recovery (WHR) system. But, both the resulting energy systems need a smart …

Investigation Of A Carbon Monoxide Dehydrogenase From An Uncultured Archaeon, Luke Moore

Dissertations, Master's Theses and Master's Reports

The Nickel based Carbon Monoxide Dehydrogenase (CODH) is an anaerobic metalloenzyme responsible for the reversible conversion of CO and water into CO2 and 2 protons and 2 electrons. This enzyme has importance in the environment as one of Earth’s first carbon fixation pathways, and for human uses as a potential source of biofuels and other commodity chemicals. CODH enzymes are present in a wide array of taxa, many of which are uncultured. In this study we express and purify the catalytic subunit (CooS) of the anaerobic CODH from an uncultured Hydrothermarchaeota JdFR-17 co-expressed with the nickel insertion accessory protein (CooC) …

An Experimental Study Towards Underwater Propulsion System Using Structure Borne Traveling Waves, Shreyas Suhas Gadekar

Dissertations, Master's Theses and Master's Reports

The method of generating steady-state structure-borne traveling waves underwater in an infinite media creates abundant opportunities in the field of propulsive applications, and they are gaining attention from several researchers. This experimental study provides a framework for harnessing traveling waves in a 1D beam immersed under quiescent water using two force input methods and providing a motion to an object floating on the surface of the water.

In this study, underwater traveling waves are tailored using structural vibrations at five different frequencies in the range of 10Hz to 300Hz. The resulting fluid motion provides a propulsive thrust that moves a …

An Analysis Of Compressive Convolutional Autoencoders For Image Archiving In Medical Informatics, Charles Warren

Dissertations, Master's Theses and Master's Reports

Within a given enterprise network, an array of data types needs to be communicated. These network transmissions consist of images, videos, text, and binaries that have unique requirements of bandwidth and computational overhead to transmit. With respect to medical informatics, these include a multitude of varying subjects, standards, and modalities which are communicated to and from imaging equipment, clinicians, and medical archives. To reduce the required bandwidth to transmit, or provide adequate storage capacity for archival purposes, the data may be compressed in such a way that reduces the size of the image when it is transferred or stored. The …

Exploring Interpretations And Consequences Of Michigan’S Expungement Statute Through Formal Modeling And Analysis, Jonathan C. Parks

Dissertations, Master's Theses and Master's Reports

Rules and regulations often come with a lack of clarity and the possibility of multiple interpretations. Without a clear understanding of what they are supposed to mean it becomes difficult to tell the people that these rules and regulations apply what to expect from them. This report will take a closer look at one of these sets of rules, the expungement laws in the state of Michigan. The alternative interpretations and possible contradictions are explored and their effects on real people are discussed. After an introduction providing a general understanding of the issue, a proposed solution to these problems will …

Development And Utilization Of Geodatabase: Predicting Biodiversity In Equatorial Guinea, Africa, Nicholas Treusch

Dissertations, Master's Theses and Master's Reports

After declaring independence in 1968 and discovering oil reserves in 1995, Equatorial Guinea has arisen as one of the wealthier countries in Africa but unfortunately has become one of the most volatile countries as well, with the numerous military coups and disproportionate distribution of wealth. This nation also houses some of the most diverse wildlife on earth, with several endangered species of mammals, as well as reptilian and bird species that are unique only to Equatorial Guinea. With increased bushmeat demand increasing in the last two decades, illegal hunting activities have increased as well, even in national parks. Because of …

Rhetoric Of Surrogacy: Re-Considering Agency Through Embodied Performance, Ann Kitalong-Will

Dissertations, Master's Theses and Master's Reports

Surrogacy as a medical practice goes back, in a practical sense, to 1988, when the court case, “In the Matter of Baby M, A Pseudonym for an Actual Person,” was tried in the Supreme Court of New Jersey. At the heart of the issue, was the question of who Baby M’s legally-recognized mother was in the relationship between the contracting parents and the woman who gestated and gave birth to Baby M. Using this case as a jumping off point, this dissertation traces a history of surrogacy as a global industry. This project explores rhetorical agency in the embodied performance …

Conservation Value Of Working Landscapes In Mesoamerica For Nearctic-Neotropical Migratory Birds, Samuel L. Oliveira

Dissertations, Master's Theses and Master's Reports

Populations of many of Nearctic-neotropical migratory birds have declined in the past several decades, recent estimates suggested a dramatic loss of 2.5 billion birds over the past 50 years in North America. Habitat loss and degradation represent a major threat in the tropics. Managed agroecosystems have the potential to mitigate some impacts of land conversion, however, little is known regarding the habitat quality provided by working landscapes in the overwintering range. In this research, we surveyed the migratory bird community in the rapidly expanding oil palm plantations in southern Mexico; and also the declining population of the Wood Thrush ( …

Investigating The Role Of Genomic Material Costs In Ecological, Evolutionary, And Invasion Dynamics Using The Solidago Gigantea (Giant Goldenrod) Polyploid Complex, Angela M. Walczyk

Dissertations, Master's Theses and Master's Reports

Polyploidy (whole genome duplication) is large-scale mutation that increases genome size and alters the genomic expression patterns, thus influencing morphological and physiological traits. Given that polyploids and progenitor diploids can be geographically segregated, and that polyploidy is prevalent in invasive plant taxa, polyploidy might affect the ability to tolerate and adapt to variable and/or novel environments. Responsiveness to soil nitrogen (N) and phosphorus (P) availability are of particular interest because 1) nucleic acids (DNA and RNA) require large amounts of N and P for their biosynthesis, potentially disadvantaging polyploids in nutrient-poor environments; and 2) biological invasions usually begin in urbanized …

Non-Chromatographic Oligonucleotide Purification And Automated Polyethyleneglycol Synthesis, Dhananjani N. A. M. Eriyagama

Dissertations, Master's Theses and Master's Reports

Synthetic oligodeoxynucleotides (ODN) have various applications in many areas such as, synthetic biology, chemical biology, antisense drug development, and data storage. As a result, there is a high demand for synthetic ODNs. Many advances have been made with ODN synthesis the purification still remains a bottleneck. The non-chromatographic purification method is developed to address this problem. Similarly, polyethylene glycols (PEGs) have been used in many areas including pharmaceutical applications, surface science, and nanomedicine due to its unique properties. However, monodispersed PEG synthesis is expensive with existing methods. A novel automated solid phase synthesis method is developed to obtain monodispersed PEGs. …

Discourse, Materiality, And The Users Of Mobile Health Technologies: A Nigerian Case Study, Modupe Omolara Yusuf

Dissertations, Master's Theses and Master's Reports

mHealth, which is the use of mobile phones and other handheld information and communication technologies (ICTs), has been increasingly advocated as the solution to the problems, primarily infrastructure and personnel, facing the healthcare sector of many low-to-lower-middle-income countries (LMICs). Following a series of United Nations Foundation research and advisory publications (in 2012, 2014 and 2016) arguing that mobile phones are approaching ubiquity in Nigeria and across the world, the UN strongly recommended that LMICs undertake mHealth initiatives. Subsequently, Nigeria’s Federal Ministry of Health (FMOH) published a National Health ICT Strategic Framework (Strategic Framework), 2015-2020; the rallying call of …

Hardware In The Loop Implementation And Simulations Of A Wave Energy Converter Using Typhoon Hil And Speedgoat, Pranav Nair

Dissertations, Master's Theses and Master's Reports

Several studies have indicated that electricity production is the prime source of greenhouse emissions, more than flying and driving combined. Hence, over the past few decades, there has been a significant rise in the need for clean energy to achieve the targets in emissions reduction. It has been observed that the share of renewable energy sources in the percentage of total electricity production is rising, but, according to climate experts, the transition needs to speed up. Hence, it is significant to study and develop underutilized renewable energy sources.

One of these underutilized renewable energy sources is wave energy. It has …