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Quantifying The Potential Of Climate Mitigation And Adaptation In The United States Agricultural System With Model-Data Integration, Peng Zhu

Open Access Dissertations

Agriculture is an important sector of U.S. economy. Faced with increasing global food demand driven by population boom, it is necessary to sustain the increasing food production. However, agricultural system is inherently sensitive to climate change and multiple lines of evidence across different spatial scales implied that the future warming will decrease global food production. In this context, this thesis focused on US cropland to investigate its potential in climate mitigation and adaptation by synthesizing the multiple crop models, long term satellite data, official survey data and field experiment. The fundamental questions addressed by this dissertation are: (1) how will …

Modeling And Mitigation Of Wireless Communications Interference For Spectrum Sharing With Radar, David P. Zilz

Open Access Dissertations

Due to both economic incentives and policy mandates, researchers increasingly face the challenge of enabling spectrum sharing between radar and wireless communications systems. In the past eight years, researchers have begun to suggest a wide variety of approaches to radar-communications spectrum sharing, ranging from transmitter design to receiver design, from spatial to temporal to other-dimensional multiplexing, and from cooperative to non-cooperative sharing. Within this diverse field of innovation, this dissertation makes two primary contributions. First, a model for wireless communications interference and its effects on adaptive-threshold radar detection is proposed. Based on both theoretical and empirical study, we find evidence …

The Effects Of Dietary Protein At Breakfast And Across The Day On Appetite Control & Satiety, Food Intake, And Sleep Quality, Jess A. Gwin

Open Access Dissertations

The movement to adopt healthful lifestyle practices to reduce the prevalence of obesity and associated chronic diseases has garnered global interest [1]. As such, the desire to consume more protein-rich foods is a commonly used strategy due to the documented improvements in weight management observed with higher-protein (HP) diets, ranging from 1.2-1.6 g protein•kg body weight-1•d-1[2-6]. One postulated mechanism through which HP diets elicit greater weight (and fat) losses includes the improvements in ingestive behavior which appear to be mediated by a number of satiety-stimulating, physiological and/or hedonic pathways, and lead to reductions in daily food intake [3]. The main …

Applications Of Multivariate Raman Spectroscopy, Sarah M. Matt

Open Access Dissertations

The vibrational Raman spectrum of water can be used to probe changes in water structure as a function of temperature and due to solute-water interactions. We have demonstrated a diverse set of these applications by combining Raman spectroscopy with self-modeling curve resolution (SMCR). To begin with, the affinity of halogen anions for both benzene and pyridine was quantified by calculating ion partition coefficients based upon vibrational spectroscopic measurements. These partition coefficients were also found to be in good agreement with those obtained from MD simulations performed in collaboration with the Tobias group at University of California, Irvine. Next, we probed …

Optical Studies Of Novel Electronic Materials, Nirajan Mandal

Open Access Dissertations

We have made a Kerr rotation (KR) measurement instrument with a 635 nm laser that is sensitive enough to measure KR angle of few micro-radians. The KR instrument was used to study the current induced polarization rotation of light as it is reflected off the surface of topological insulator Bi2Te2Se (BTS221). In our experiment, we observe a linear response of Kerr rotation with current and the Kerr rotation for both s and p-polarized light is negative. From the dependence of this polarization rotation on the current in the TI sample, the angle of incidence of light and the light polarization, …

Mass Spectrometric Studies On A Functional Group-Selective Ion-Molecule Reaction And The Reactivity Of Bi And Polyradicals, Joann P. Max

Open Access Dissertations

Mass spectrometry (MS) is a versatile analytical tool for the characterization of unknown compounds in complex mixtures. MS separates the ionized components of a mixture based on their m/z values and provides accurate molecular weight information and elemental compositions for the ionized analytes. Tandem mass spectrometry (MS/MS) based on collision-activated dissociation or ion-molecule reactions can be used for structural characterization of the ionized analytes. MS/MS can also be used to probe the intrinsic properties of highly reactive intermediates that are difficult to study in solution. The experiments described in this thesis focus on the examination of various gas-phase reactions. A …

High School Redesign And The Senior Year, Park D. Ginder

Open Access Dissertations

The purpose of this qualitative study was to describe how high school principals in Indiana are redesigning senior year academic experiences as a means to increasing student engagement and making the senior year more valuable for students. Using an exploratory multiple-case study design, three high school principals serving in high performing high schools in Indiana (as defined by the Indiana Department of Education rating each school an “A”) were interviewed, with interviews recorded and transcribed, then coded for item analysis. The participants’ commentary, outlined themes, and sub-themes from the case study provide insight into the experiences of high school principals …

Functional Organization Of The Brain At Rest And During Complex Tasks Using Fmri, Lauren Kelly Lynch

Open Access Dissertations

How and why functional connectivity (FC), which captures the correlations among brain regions and/or networks, differs in various brain states has been incompletely understood. I review high-level background on this problem and how it relates to 1) the contributions of task-evoked activity, 2) white-matter fMRI, and 3) disease states in Chapter 1. In Chapter 2, based on the notion that brain activity during a task reflects an unknown mixture of spontaneous activity and task-evoked responses, we uncovered that the difference in FC between a task state (a naturalistic movie) and resting state only marginally (3-15%) reflects task-evoked connectivity. Instead, these …

Investigating The Purported Slow Transit And Starch Digestion Of Whole Grain Foods, Elizabeth Anne Pletsch

Open Access Dissertations

Epidemiological studies have strongly supported the substitution of whole grains or whole grain foods for refined grains in the diet to reduce the risk of type II diabetes and other chronic diseases. However, the mechanisms of whole grain digestion, and the properties that are responsible for the associated responses of low glycemia and slow transit time of whole grains are still not well understood. The moderated glycemic response related to consumption of whole grains is largely associated with dietary fiber, yet there are properties of other components, such as starch itself, that warrant further investigation. Gastric emptying rate, or the …

Fractionation Of Corn Stover With Effective Shredding And Separation, Jiechao Ma

Open Access Dissertations

A corn stover shredder using a flail type knife and tine shredding mechanism was designed, fabricated, and tested with the objective of improving the shredding extent with corn stover. Two machine designs (open hood with exit chute and closed hood with slots) and three moisture content levels (5, 40, and 70% w.b.) were studied. Shredding was more effective (higher leachate ion conductivity index representing better access to plant nutrients) with the closed hood with slots design than with the open hood design (p<0.001). Extent of shredding was proportional to moisture content at the time of shredding. The attempt to process the corn stover at 70% w.b. was promising as it resulted in a highest leachate ion conductivity (LIC) index of 86%, which is comparable to that of hammer-milled dry stover. Two speeds for the shredding rotors (no-load speeds of 1300 and 700 rpm) were tested with the three moisture levels and the closed-hood with slots design but shredding speed did not affect LIC (p>0.25). To ascertain the tissue make-up of stover samples (rind, pith, leaf, and husk percentages) a multi-trait …

The English In The Levant: Commerce, Diplomacy, And The English Nation In The Ottoman Empire, 1672-1691, Zachary W. Schulz

Open Access Dissertations

This dissertation examines the English who went to the Levant. Specifically, it analyzes the merchants, factors, ambassadors, chaplains, and embassy staff members who traveled to the Near East for either bureaucratic, commercial, or scholastic motivations. During their time abroad, these men amassed a wealth of knowledge and pecuniary resources, simultaneously furthering the countless interests forced upon them by the Levant Company and/or the English government. Thus, this dissertation asserts that the Ottoman Empire acted as a training ground for English emissaries, providing those who were abroad with the means of returning home to better positions of political, commercial, and/or diplomatic …

Sub-10nm Transistors For Low Power Computing: Tunnel Fets And Negative Capacitance Fets, Ankit Sharma

Open Access Dissertations

One of the major roadblocks in the continued scaling of standard CMOS technology is its alarmingly high leakage power consumption. Although circuit and system level methods can be employed to reduce power, the fundamental limit in the overall energy efficiency of a system is still rooted in the MOSFET operating principle: an injection of thermally distributed carriers, which does not allow subthreshold swing (SS) lower than 60mV/dec at room temperature. Recently, a new class of steep-slope devices like Tunnel FETs (TFETs) and Negative-Capacitance FETs (NCFETs) have garnered intense interest due to their ability to surpass the 60mV/dec limit on SS …

Development Of High-Capacity Anodes For Advanced Li-/Na- Ion Rechargeable Batteries, Jialiang Tang

Open Access Dissertations

Since the introduction of the first commercial lithium ion batteries (LIBs) by Sony in 1991, LIBs have dominated the rechargeable energy storage market owing to their high energy density, good cycling stability, and long cycle life. By 2020, the global LIBs market revenue is projected to reach $76 billion dollars, a five-fold increase from 2013. To better accommodate the rising demand, research efforts are intensifying to develop next-generation LIB chemistries (i.e., silicon anodes and sulfur cathodes) that offer much higher energy densities. At the same time, concerns over lithium shortage have prompted research into sodium ion batteries (SIBs), a potentially …

Transfer Of Antibiotic Resistance In Enterococcus Faecalis. Modeling And Computational Study, Vu Tran

Open Access Dissertations

Bacteria of the genus Enterococcus, commonly found in the intestinal tract, are the main cause of antibiotic-resistant infections that are acquired in hospitals[1], [2]. Donor cells that contain plasmid pCF10 have the ability to resist to antibiotics and are capable of transferring this plasmid to recipient cells. This transfer occurs via a rapid horizontal inducible conjugation regulated by peptide-mediated cell-cell signaling molecules (quorum sensing), known as cCF10 and iCF10. This quorum sensing system functions by producing low levels of an inducing substance that accumulates in the environments until a threshold is reached, at which point there is a change in …

Quality And Nutritional Impacts Of Extrution On Pearl Millet And Nutrient Dense Native Plant Blends, Cheikh Ndiaye

Open Access Dissertations

Significant efforts have been placed on the development of strategies to address micronutrient deficiencies in Sub-Saharan parts of Africa. Improving the nutritional value of staple foods, including cereals, is a key component of such strategies as traditional cereals such as millet and sorghum are mostly consumed in these areas. Of micronutrient deficiencies, iron, zinc and vitamin A are most critical, and mostly deficient in staple cereal foods. One option to improve the nutrient density of cereal foods is to leverage natural micronutrient dense plant materials that exist locally, and can be formulated into cereals products. Such products can be combined …

Analysis And Design Of Lubricating Interfaces In External Gear Machines For High And Low Viscous Working Fluids, Divya Thiagarajan

Open Access Dissertations

Lubricating interfaces represent a significant design constituent which contribute to the reliability and efficiency of many modern designs of gap compensated external gear machines (EGMs). However, the complex nature of the influence of fluid behavior in these interfaces on the structural and thermal effects of the solid components involved in the lubricating gap makes their design quite challenging. Moreover, the extensive range of applications currently available for EGMs warrant designs which can perform efficiently at extended range of operating conditions as well as with a comprehensive variety of working fluids. In order to improve the understanding of the physics in …

Transport Theory For Materials With Spin-Orbit Coupling: Physics To Devices, Shehrin Sayed

Open Access Dissertations

Materials with spin-orbit coupling (SOC) exhibiting spin-momentum locking (SML) are of great current interest in spintronics because of their ability to efficiently convert charge signals into spin signals and vice versa. This dissertation develops a generalized diffusion equation with four electrochemical potentials starting from the standard Boltzmann transport equation and maps it to a transmission line model. This model applies to diverse materials with SOC including topological insulators, transition metals, narrow bandgap semiconductors, perovskite oxides, etc. and presents a new viewpoint suggesting that materials with low Fermi wave vector lead to larger spin voltages. The model has been used to …

Opto-Electro-Thermal Approach To Modeling Photovoltaic Performance And Reliability From Cell To Module, Xingshu Sun

Open Access Dissertations

Thanks to technology advancement in recent decades, the levelized cost of electricity (LCOE) of solar photovoltaics (PV) has finally been driven down close to that of traditional fossil fuels. Still, PV only provides approximately 0.5% of the total electricity consumption in the United States. To make PV more competitive with other energy resources, we must continuously reduce the LCOE of PV through improving their performance and reliability. As PV efficiencies approach the theoretical limit, however, further improvements are difficult. Meanwhile, solar modules in the field regularly fail prematurely before the manufacturers 25-year warranty. Therefore, future PV research needs innovative approaches …

Reactivity And Characterization Of Intermetallic Alloy Catalysts For Alkane Dehydrogenation, Evan C. Wegener

Open Access Dissertations

As the United States works towards energy independence shale gas has become an attractive domestic recourse for use as a feedstock to produce fuels. One potential approach to utilize shale gas is to first convert the C2 and C3 paraffinic components into olefins, valuable chemical building blocks, by catalytic dehydrogenation. The goal of this dissertation is to study how the geometric and electronic changes to a metal upon alloying influence its selectivity for light alkane dehydrogenation. In the first three projects bimetallic catalysts comprising of either Pd or Pt and a post-transition metal known to promote olefin selectivity were investigated. …

Real-Time Stochastic Predictive Control For Hybrid Vehicle Energy Management., Kyle R. Williams

Open Access Dissertations

This work presents three computational methods for real time energy management in a hybrid hydraulic vehicle (HHV) when driver behavior and vehicle route are not known in advance. These methods, implemented in a receding horizon control (aka model predictive control) framework, are rather general and can be applied to systems with nonlinear dynamics subject to a Markov disturbance. State and input constraints are considered in each method. A mechanism based on the steady state distribution of the underlying Markov chain is developed for planning beyond a finite horizon in the HHV energy management problem. Road elevation information is forecasted along …

Plant Mediated Effects On Tritrophic Interactions In The Solanaceae-Hornworm System, Michael A. Garvey

Open Access Dissertations

Top-down pressure from parasites is thought to be a key driver in herbivore diet breath, but studies investigating the evolution of food plant shifts as a defense against natural enemies in the environment are still lacking in the literature. I examined how plants alter insect-enemy interactions for a specialist herbivore utilizing solanaceous food plants, Manduca sexta (the tobacco hornworm) and the parasitoid wasp, Cotesia congregata, as a model. In this study, I documented parasite infections in a field population of M. sexta, and then investigated from an eco-immunological perspective how plant toxins influence susceptibility to parasites in order to explain …

A Performance-Based Framework For Guiding Enroute Air Traffic Control Sector Design, Julian R. Archer

Open Access Dissertations

Sectors are small regions of airspace through which aircraft fly and air traffic controllers are required to manage while considering notions like safety, efficiency, and effectiveness. Interestingly, we do not know how to design, i.e. make considerations surrounding airspace, air traffic, controller, and technology factors, such that sectors generate specific levels of performance. Rather, sectors have always been designed in an artistic fashion where the focus is on human operator workload, which is fairly subjective. This research leverages the fact that many aspects of performance are objective and so are many aspects of design. A framework is proposed such that …

Photoassociation In 87rb Becs And In Ultracold 7li85rb, David Blasing

Open Access Dissertations

In this thesis, we have measured PA rates to a spin-dependent molecule in a 87Rb BEC, and also, in a separate line of experiments, excitation and subsequent spontaneous decay of ultracold 7Li85Rb d3Π molecules. The main contribution of the experiment on 7Li85Rb was the observation of multiple new a3Σ` molecules that resulted from the spontaneous decay of the excited d3Π molecules. From those exper3Σ` iments, we were able to predict a feasible pathway to produce a molecules in its lowest virbational level at significant rates. The main contribution of the experiment on 87Rb BECs was the observation of an anomalous …

Strategies To Create Interfacial Patterning And Epitaxial Architectures Using Controllable Anisotropic Wetting At Scales <10nm On Polyfunctional Noncovalent Ligand Layers, Shi Wah Choong

Open Access Dissertations

Chemical orthogonality at sub-10 nm is important in synthetic material applications. Synthetic materials require surfaces with two very different types of chemistry. For instance, nanoelectronics require repeating units of metal and oxide at 5- and 7-nm length scales.1-3 In polymer solar cells, the capability to cause n-type and p-type blocks to phase segregate at length scales < 10 nm would provide more efficient charge transport.4-6 Increasingly high resolution patterning has been achieved using lithographic techniques to manufacture devices with features as small as 14 nm and in some cases smaller.7-11 It is extremely difficult to precisely engineer and fabricate 3D interfaces with features less than 10 nm and high cost is associated with it.12-14 However, nature routinely addresses a similar challenge in the context of lipid bilayer, which has a thickness of about 6 nm. Lipid bilayer is made of phospholipids with an alternating hydrophilic and hydrophobic pattern to control the flow of water, ions and other small molecules across the cell membrane. The orthogonality of the lipid bilayer is hidden in the membrane core along the z-axis but for applications in nanoelectronics and organic photovoltaics, both chemical functionalities need to be displayed on the surface. My dissertation research focused on using bio-inspired molecules to create precisely patterned layered materials with chemical orthogonality of ~6 nm, and utilizing these noncovalent monolayers to achieve molecular-scale wetting control, to create nanometer-thick film along the rows of headgroups using polar liquid as well as utilizing these polyfunctional layered materials to template epitaxial nanocrystals of small organic molecules. In this dissertation work, I have created nanoplates with thickness of ca. 1 nm as well as nanorods with length ~21 nm and width ~6 nm, which is similar to the lamellar width of the templating monolayers. These nanostructures adopt epitaxial alignment along the lamellae of the amphiphilic monolayers. My thesis work shows potential strategies useful for precise interfacial patterning for synthetic material applications at very short length scales.

Process Characterization And Optimization Of Roll-To-Roll Plasma Chemical Vapor Deposition For Graphene Growth, Majed A. Alrefae

Open Access Dissertations

Large-scale production of graphene and other nanostructures remains a hindrance to their adoption in the semiconductor and materials manufacturing industries. The main purpose of this thesis is to develop an efficient and scalable technique for depositing graphene on various flexible substrates. Hence, a custom-built roll-to-roll capacitively coupled plasma chemical vapor system for deposition of graphene on flexible substrates is thoroughly described in this work. Graphene quality on Cu foil has been optimized for a roll-to-roll process using statistical optimization methods. Since graphene quality and uniformity depend on plasma input parameters, such as plasma power, gas pressure, and the gas mixture …

Multidimensional Nonlinear Optical Imaging, Fengyuan Deng

Open Access Dissertations

The work in this dissertation is focused on extending the information content for second harmonic generation (SHG) and two-photon excited fluorescence (TPEF) imaging. Despite the simplicity and symmetry selectivity of nonlinear optical processes, limited information on chemical composition can be recovered solely based on intensity measurements. To further explore the potential for second order nonlinear optical (NLO) measurements, additional dimensions were added to the NLO imaging platforms. By combining NLO microscopy with powder X-ray diffraction, a novel approach was established for accessing percent crystallinity in amorphous solid dispersions (ASDs) with a limit of detection in the ppm range. ASDs are …

Teacher Identity And The Role Of Relational Coaching, Melinda R. Ehmer

Open Access Dissertations

The purpose of this study was to identify specific strategies that principals use when coaching teachers who struggle to develop positive relationships with students. Using a qualitative case study design, six principals were identified through the use of a demographic survey. The principals were interviewed about their experiences. Each interview was recorded, transcribed, and coded for data analysis. The principals’ narratives, emerging themes and sub themes provide insight into their experiences with both relational and non-relational teachers. The emerging themes are: (a) relationship building for teachers and students; (b) coaching strategies; (c) roadblocks and deficiencies; and (d) identity and belief …

Quantum Correlations In Nanophotonics: From Long-Range Dipole-Dipole Interactions To Fundamental Efficiency Limits Of Coherent Energy Transfer, Cristian L. Cortes

Open Access Dissertations

Quantum properties like coherence and entanglement can lead to enhanced performance characteristics in a wide range of applications including quantum computation, quantum memory storage, optical sensing, and energy harvesting. Entanglement is very sensitive to static and dynamical disorder. Similarly, the generation of highly-entangled states requires strong coupling or strong driving fields. Satisfying all of these requirements is generally quite difficult. In the first part of this thesis, we present an approach to overcome these limitations through the use of exotic light-matter states in hyperbolic media which provide a new approach to control quantum correlations and interatomic interactions. We reveal a …

Improving Information Alignment And Distributed Coordination For Secure Information Supply Chains, Omar Eldardiry

Open Access Dissertations

Industries are constantly striving to incorporate the latest technology systems into their operations so that they can maintain a competitive edge in their respective markets. However, even when they are able to stay up to speed with technological advancement, there continues to be a gap between the workforce skill set and available technologies. Organizations may acquire advanced systems, yet end up spending extended periods of time in the implementation and deployment phases, resulting in lost resources and productivity. The primary focus of this research is on streamlining the implementation and integration of new information technology systems to avoid the dire …

Design Methodology For A High-Frequency Transformer In An Isolating Dc-Dc Converter, Veda Samhitha Duppalli

Open Access Dissertations

The objective of this work is to propose a design methodology for a high-frequency transformer in the context of an isolating DC-DC converter. The design challenges relating to high-frequency operation include transformer parasitics, high-frequency loss mechanisms, and their coupled effect on the performance of the transformer and DC-DC converter. These issues are addressed in this work by incorporating high-frequency effects into the relevant magnetic, electrical, and thermal analyses needed for multi-objective optimization based design.

First, an accurate and computationally-efficient method for the transformer magnetic analysis is proposed. Leakage inductance is calculated using a procedure based on the Biot-Savart law and …