Engineering Commons^™

Ultrawide Bandgap Algan-Channel Metal Oxide Semiconductor Heterostructure Field Effect Transistors With High-K Gate Dielectrics, Md Abu Shahab Mollah

Theses and Dissertations

Ultra-wide Band Gap (UWBG) (E_G > 3.4 eV) Al_xGa_1-xN channel devices are promising candidates for compact next-generation power electronics due to the scaling of the breakdown field with alloy composition. The huge opportunity in consumer electronics is the major driving force behind the recent developments of UWBG AlGaN-channel HEMTs. One of the most critical issues limiting the device performance at high power level is device degradation primarily caused by gate leakage current. Use of SiO₂ gate insulator is a standard method to suppress gate leakage but it causes threshold voltage shift towards more negative requiring …

Impact Of Acetylcholine On Internal Pathways To Basal Amygdala Pyramidal Neurons, Tyler Daniel Anderson-Sieg

Theses and Dissertations

The basolateral nuclear complex of the amygdala (BNC) – consisting of the lateral (LA), basolateral (BL), and basomedial nuclei (BM) – detects salient environmental stimuli (cue-detection) and motivates appropriate behavioral responses to their implied meaning (cue-guided behavior) via a precise pattern of internal circuitry. Glutamatergic signals representing environmental stimuli enter the LA and split into parallel streams that activate pyramidal neurons (PNs) in the anterior and posterior BL (BLa and BLp), which putatively mediate negative and positive emotions, respectively. The BL is the most densely innervated target of the cholinergic basal forebrain (CBF) and ACh transients (phasic ACh) in cortex …

Impaired Metabolic Flexibility In A Mouse Model Of Leigh Syndrome, Richard Sterling Mccain Jr

Theses and Dissertations

Metabolic dysfunction burdens tissues with high energy demands, particularly the brain. Leigh syndrome is a mitochondrial encephalopathy stemming from genetic defects in the electron transport chain. Leigh syndrome patients develop lactic acidosis, ataxia, bilateral necrotizing lesions in the brainstem and basal ganglia, lesion microgliosis, and eventually death due to respiratory failure. The NADH dehydrogenase [ubiquinone] iron-sulfur protein 4 (NDUFS4) knockout mouse is an established model of Leigh syndrome due to impaired assembly of mitochondrial Complex I that develops motoric deficits and necrotizing lesions in the brainstem vestibular nuclei and olfactory bulb. In addition to the Complex I-derived bioenergetics defect, altered …

Robust Adaptive Model Predictive Control Of Nonlinear Sample-Data Systems, Lixing Yang

Theses and Dissertations

In the past decades, model predictive control (MPC) has been widely used as an efficient tool in areas such as process control, power grids, transportation systems, and manufacturing. It provides an approach that aims to design stabilizing feedback to the system so that the performance criterion gets minimized while the state and input constraints get satisfied. In many situations, MPC may outperform other approaches to design and implement feedback control systems. Furthermore, MPC may solve optimization problems with large and practically important sets of multiple-input multiple-output (MIMO) systems efficiently. A typical implementation of MPC predicts the optimal control inputs that …

Temperature Dependence Of Electroluminescence And Current-Voltage Characteristics Of Arrays Of Deep Ultraviolet Algan Micropixel Led, Dhruvinkumar Prakashchandra Patel

Theses and Dissertations

III-Nitride based deep ultraviolet (DUV) light emitting diodes are non-toxic light sources that are highly desirable to replace current mercury lamp-based technology for air and water purification, surface and object disinfection, and sterilization. In the present. By freezing out defect related conduction pathways at temperatures less than 50K, the external quantum efficiency (EQE) of an interconnected array of 1,296 AlGaN DUV micropixels is improved by 4 times, underscoring the importance of defect management. Assuming a current injection efficiency (CIE) of 100% and considering that the light extraction efficiency (LEE) is constant with temperature, the 4-fold increase in the EL signal …

Time-Domain Measurement Of Magnetization Dynamics In Ferrofluids, Brian Egenriether

Theses and Dissertations

Time-domain measurements are made on a magnetite-based (Fe3O4) ferrofluid using an inductive technique. The constituent particles are 5.8% by volume, polydisperse, and have a nominal diameter of 10nm with a ~1nm-thick anionic hydrophobic coating. The ferrofluid is placed in a sealed channel on a coplanar waveguide (CPW) situated in an adjustable external magnetic bias field. A fast-rising step current in the CPW quickly reorients the local magnetic field above the signal trace causing the particles’ moments to align in the new field configuration. This changing magnetization induces a voltage in the CPW that is detected by a sampling oscilloscope. Precessional …

Real-Time Probabilistic Solvers For Digital Twins Of Power Electronic Systems, Matthew Aaron Milton

Theses and Dissertations

In recent years, switching power electronic systems for use in power conversion, generation, and distribution have become increasingly larger and complex in their design. With the increase in complexity comes the increase in difficulty in performing analysis, experiments, and health management on such systems in physical space. Part of this difficulty comes from challenge of access to and understanding of the internal interplay of the numerous components, safety and cost of system operation, and the inherent uncertainty of physical characteristics of systems and their environment.

A recent approach for testing and diagnostics/prognostics of power electronic systems is the application of …

Role Of Ahr Ligands In Immune Modulation To Suppress Inflammation Through The Regulation Of Microrna And Gut Microbiome, Osama Azeldeen Abdulla

Theses and Dissertations

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor and an environmental sensor that is highly conserved evolutionarily. It was first discovered in the early 1970s for its ability to bind with high affinity to 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), an environmental pollutant and induce a xenobiotic-metabolizing enzyme known as aryl hydrocarbon hydroxylase (AHH). AhR was shown to regulate TCDD-mediated toxicity against a variety of tissues including the immune system. More recently, AhR has been characterized as key regulator of the immune system, specifically the differentiation of T cells. Also, several AhR ligands have been characterized in addition to TCDD such as …

30 Ghz Path Loss Modeling And Performance Evaluation For Noncoherent M-Ary Frequency Shift Keying In The 30 Ghz Band, Mohanad Razak Mohsen

Theses and Dissertations

A candidate millimeter-wave (mmWave) frequency band and modulation scheme that could fit to many present and future applications has been presented in this work. As is being explored by industry, we also suggest the 30 GHz band as a candidate carrier frequency and non-coherent frequency shift keying (NC-FSK) as a potential modulation scheme for future communication applications. The primary applications are aimed at 5th generation (5G) cellular type systems. Propagation measurements were conducted for outdoor and indoor environments using directional horn antennas for both co-polarized and cross-polarized antenna configurations to model the path loss for our candidate band. The measurements …

Methods For Dynamic Stabilization, Performance Improvement, And Load Power Sharing In Dc Power Distribution Systems, Hessamaldin Abdollahi

Theses and Dissertations

Modern DC power distribution systems (DC-PDS) offer high efficiency and flexibility which make them ideal for mission-critical applications such as on-board power systems of All-Electric ships, electric vehicles, More-Electric-Aircrafts, and DC Microgrids. Despite these attractive features, there are still challenges that need to be addressed. The two most important challenges are system stability and load power sharing. The stability and performance are of concern because DC-PDS are typically formed by the interconnection of several feedback-controlled power converters. The resulting interactions can lead to destabilizing dynamics. Likewise, in a DC-PDS there are several source converters that are operating in parallel to …

Room Temperature Semiconductor Radiation Detectors Based On Cdznte And Cdzntese, Mohsin Sajjad

Theses and Dissertations

In recent years, there have been considerable interests in nuclear radiation detectors for national security and nuclear safeguard including monitoring special nuclear materials and nuclear waste characterization, for medical imaging devices using nuclear medicine such as positron emission tomography (PET), and for NASA space astronomy. One of the most promising semiconductors being considered for the field-deployable nuclear detector is cadmium zinc telluride (CdZnTe or CZT). CZT is a ternary semiconductor that can efficiently stop and detect high-energy gamma-rays at room temperature. CZT has desirable properties for efficient nuclear radiation detection and imaging due to high atomic number (Z ~ 50, …

17 Β-Estradiol And Phytoestrogens Attenuate Apoptotic Cell Death In Hiv-1 Tat Exposed Primary Cortical Cultures, Sheila Marie Adams

Theses and Dissertations

Despite the advent of highly active antiretroviral therapy (HAART), neurological disorders develop in most people infected with human immunodeficiency virus type 1 (HIV-1). The poor CNS delivery of anti-retrovirals allows continued virus production and renders neurons susceptible to the toxic effects of released viral proteins. The neurotoxic potential of HIV-1 viral protein Tat has been shown to include excitotoxicity, oxidative stress, and mitochondrial dysfunction leading to subsequent cell death. Thus, Tat is thought to have a key role in the pathogenesis of HIV-associated neurodegeneration. Estrogens are universally considered to be neuroprotective, as such; estrogens have positive implications in the treatment …

Design Of High Efficiency Wireless Power Thansfer System With Nonlinear Resonator, Yibing Zhang

Theses and Dissertations

Wireless power transfer technology (WPT) has been rapidly developed in recent years. The primary benefit of WPT is that it replaces the traditional wire charging with a cordless charging method. WPT technology has been applied in many fields, such as bio-implants, electric vehicles, and wirelessly charging systems. According to the different energy transmission mechanism, WPT technology can be divided into magnetic field coupling (includes magnetically coupled inductive and magnetically-coupled resonant), microwave radiation, laser emission, electrical-field coupling, and ultrasonic transmission type. Among these technologies, the magnetic resonance coupling method has a better promise because of its long transfer distance and high …

Expansion Microscopy: A New Approach To Microscopic Evaluation, Ashley Ferri

Theses and Dissertations

Optical microscopy resolution is limited by the wavelengths of light and the series of microscope lenses and other optical components used to create a magnified image of cell structures in a sample. Often the cell structures are smaller or closer together than the resolution limits of a light microscope. In 2015 the Boyden group at the Massachusetts Institute of Technology (MIT) created a sample preparation technique, expansion microscopy which involves embedding biological samples in a crosslinked, swellable, hydrogel polymer that allows for uniform physical separation of cell components so that they can subsequently be resolved by light microscopy. Using the …

The Hybridization Of A Graphene And Silicon Carbide Schottky Optoelectronic Device By The Incorporation Of A Lead Sulfide Quantum Dot Film, Joshua Letton

Theses and Dissertations

The work that follows examines the impact of lead sulfide quantum dots on a native epitaxial graphene (EG) SiC Schottky device, resulting in a hybrid optoelectronic device which presents a possible avenue towards a novel hybrid carbide-based Schottky solar cell. The active (n-type SiC) and contact (graphene) layers for the Schottky junction of the device were grown epitaxially using a novel technique incorporating tetrafluorosilane (TFS) as a precursor gas. The bare EG/SiC device was characterized based on its I-V behavior in dark and under illumination for both forward and reverse bias conditions. The initial characterization demonstrated the expected Schottky diode …

Novel Multi-User Chirp Signaling Schemes For Future Aviation Communication Applications, Nozhan Hosseini

Theses and Dissertations

Many wireless communication systems will need to accommodate a larger number of users in the future. One application in particular in which this is critical is low data rate, long range communication links with very large numbers of nodes, such as the internet of things (IoT), possibly the internet of flying things (IoFT), etc. These systems demand advanced multi-access techniques with minimal multiple access interference (MAI). They should also be robust to multiple impairments, including multipath channel distortions, Doppler spreading, and interference. Chirp waveforms are one type of waveform set that can satisfy future system demands in the presence of …

Channel Modeling And Tropospheric Effects On Millimeter Wave Communications For Aviation Applications, Jinwen Liu

Theses and Dissertations

Next generation communication systems will be designed to be faster, more secure and easier to connect with than current systems. Along with the concept of internet of things (IoT), many more devices will be required to communicate with each other. In the case of aeronautical vehicles and systems, in addition to current navigation and surveillance systems, more data links will be required for multiple applications, such as photography, inspections, and entertainment. Current aviation frequency bands will likely be unable to support all proposed services. Apart from air-to-ground (AG) communication links, airport surface terrestrial links and satellite-to-air links (SA) are also …

Data-Driven Modeling Through Power Hardware In The Loop Experiments: A Pv Micro-Inverter Example, Hayder Dawood Abbood Almukhtar

Theses and Dissertations

The increasing penetration of wind turbines, photovoltaics (PV), fuel cells, microturbines, cogeneration, energy storage systems, and other Distributed Energy Resources (DER) presents both challenges and opportunities for distribution systems. A deep understanding of the characteristics of those devices, as well as accurate modeling, are essential to plan, design, and control modern distribution grids.

The objective of this research is to define data-driven modeling techniques that allow capitalizing on the results of Hardware In the Loop (HIL) and Power Hardware In the Loop (PHIL) testing by creating models of the devices under test (DUT) –also for closed-source, proprietary systems– using the …

Helicobacter’S Effects On Colitis/Colon Cancer And The Response To Indole 3-Carbinol, Rasha Raheem Abdulhamza Alkarkoushi

Theses and Dissertations

Enterohepatic Helicobacter (EHH) species are gram-negative bacteria, which are poorly studied. Several studies suggest that EHH species contribute to inflammatory bowel disease IBD in humans. IBD and colorectal cancer (CRC) has emerged as a public health challenge worldwide. Indole-3-carbinol (I3C) is one of the natural dietary indoles abundant in Brassica (cruciferous) vegetables. The aryl hydrocarbon receptor (AhR) plays an essential role as a regulator by controlling the balance between Tregs and Th17 cells. The activation of AhR by ligands derived from food or intestinal microbiota is an essential control mechanism in that balance. Moreover, many studies showed indoles achieving chemo-preventive …

Optimization Of Vehicle To Grid System In A Power System With Unit Commitment, Charles Uko

Theses and Dissertations

This thesis provides a comprehensive overview and analysis of the benefits of using plug-in electric vehicles (PEVs) in solving the unit commitment problem. PEVs are becoming more attractive and a rapid replacement of conventional fuel vehicles due to their environmental-friendly operation. Through collective control by an aggregator, PEVs batteries can also provide ancillary services such as load leveling and frequency regulation to improve the quality of power supplied in the power grid and reduce the cost of power generation. This study presents the modeling, simulation, and analysis of a vehicle-to-grid (V2G) system connected to a smart power grid. The model …

Tissue-Specific Roles Of Transforming Growth Factor Beta Ligands In Cardiac Outflow Tract Malformations And Calcific Aortic Valve Disease, Nadia Al-Sammarraie

Theses and Dissertations

Congenital heart defects and adult calcific aortic valve disease are two of the leading causes of morbidity and mortality worldwide. To date, there is no medical cure and surgical intervention is the main option of treatment. The cardiac outflow tract is the major site for these abnormalities, which are triggered by genetic and/or environmental factors that alter development and/or homeostasis. Recently, significant roles of TGFβ signaling in development of cardiovascular disorders have become more evident in humans, however, the specific requirement of individual TGFβ ligands on the pathogenesis of OFT malformations and diseases remains elusive. In the present work, three …

Wireless Rf Induced Energy Absorption And Heating Of Lanthanum-Nickel Alloy In The Near-Field, Michael Dillon Lindsay

Theses and Dissertations

This thesis will investigate whether and how a synthetic metal-magnetic alloy absorbs enough near-field electromagnetic (EM) radiation for heating. Although resistive elements could be used for indirect heating, a wireless radio frequency (RF) method is explored because of its advantages in its non-intrusive nature and its ability to direct or focus energy within a specific area. For our case, the RF heating process relies on the materials ability to absorb sufficient RF energy due to the induced currents. We expect there to be significant surface resistance due to the conductivity and magnetic permeability of the material and thus heat. This …

Astrocyte Sensitivity To Dopamine In Culture And Ex Vivo, Ashley L. Galloway

Theses and Dissertations

Dopamine is critical for processing of reward and etiology of drug addiction. Astrocytes throughout the brain express dopamine receptors, but consequences of astrocytic dopamine receptor signaling are not well established. This thesis illustrates effects of dopamine on cultured astrocytes and astrocytes in brain slices (ex vivo). In striatal cultures, extracellular dopamine triggered changes in astrocytic Ca²⁺ signaling and rapid concentration-dependent stellation of astrocytic processes that was not a result of dopamine oxidation, but instead relied on both cAMP-dependent and cAMP-independent dopamine receptor signaling. To isolate possible mechanisms underlying these structural and functional changes, whole-genome RNA sequencing was …

Role Of Epigenetic, Molecular And Cellular Pathways In The Regulation Of Inflammation, William James Becker

Theses and Dissertations

Dysregulated inflammation is at the heart of countless human diseases. Graft rejection is the process by which an organ from an incompatible donor is rejected by the recipient whose immune cells attack the foreign tissue. Colitis is an inflammatory disorder caused by undue chronic inflammation in the colon and rectum that can progress to cancer. Colitis incidence is on the rise, especially in developing nations and Asia; and the list of patients who need organ transplants grow by the day. Therapies for both graft rejection and colitis are limited to immunosuppressive drugs that leaves patients vulnerable to infection, heart disease, …

Dc Bus Stabilization And Dynamic Performance Improvement Of A Multi-Converter System, Silvia Arrua

Theses and Dissertations

Evolution of semiconductor devices is allowing to implement power electronics technology in a variety of applications, moving traditional AC systems to more efficient and reliable DC systems. Some examples are shipboard power distribution systems, DC microgrids, electric vehicles and more electric aircrafts. Even though these types of systems offer significant advantages that make them attractive in different areas, the interconnection of feedback-controlled power converters leads to emergent dynamic behavior that a system designer must take into account to ensure proper operation of the system. Additionally, system reconfiguration is very likely to happen in applications such as a shipboard power distribution, …

The Contribution Of Adipose Tissue From Ovariectomized Mice To Colon Cancer, Meredith Smith Carson

Theses and Dissertations

Obesity is considered a major public health concern worldwide due to the increased incidences of metabolic dysfunction and cancer risk. The obese state is, in part, attributable to the overconsumption of calorie-dense foods commonly seen in a standard Western diet, which aids in the progression of chronic, lowgrade inflammation. The role of estrogen varies depending on menopausal status, where estrogen deficiency coupled with increased visceral fat associated with post-menopause leads to increased secretions of pro-inflammatory adipokines and cytokines. However, the presence of estrogen in a premenopausal state has been shown to attenuate the pro-inflammatory response, which has been demonstrated when …

Fractional Order And Virtual Variable Sampling Design Of Repetitive Control For Power Converters, Zhichao Liu

Theses and Dissertations

With the growth of electricity demand and renewable energy power source, power converter becomes a more and more significant component in electrical power systems. The requirement of the power converter controller is to produce an accurate and low-distorted voltage or current under different load conditions. Although the conventional controller can meet the requirement of some applications, it requires accurate knowledge of the system model and cannot provide a satisfactory result especially under nonlinear loads or sudden load change. Repetitive control (RC) presents an attractive solution to achieve excellent steady-state tracking error and low total harmonic distortion for periodic signals, and …

Curbside Antenna To Vehicle Path Loss Measurements And Modeling In Three Frequency Bands, Patrick Murphy

Theses and Dissertations

V2V and V2I systems have been an increasingly important topic of study in recent years. Future V2I systems could involve antennas near or on the curb at intersections or on the ground along highways. To this end the curbside antenna to vehicle channel has not been studied very much. The scope of this thesis is to develop initial models for the path loss for examples of this channel. This was done through a measurement campaign where the transmitting antenna is located on the ground near the road and the receiver is in a vehicle driving towards the transmitter. The vehicle …

Effect Of Tcdd, An Environmental Contaminant, On Activation Of Ahr Leading To Induction Of Myeloid Derived Suppressor Cells (Mdscs) And The Ability Of Resveratrol, A Botanical, To Neutralize This Effect, Wurood Hantoosh Neamah

Theses and Dissertations

Aryl hydrocarbon receptor (AhR), is a ligand-activated transcription factor that integrates environmental, dietary, microbial and metabolic cues to control various cellular processes, such as the cell cycle, epithelial barrier function, cell migration and immune function. AhR was discovered as the receptor that binds with high affinity to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and leads to numerous of toxicological outcomes. In the current study, we discovered a critical role played by AhR, following activation by TCDD, in modulating a variety of immunological functions through regulation of epigenetic and microbial pathways. Our data demonstrated that AhR activation triggers MDSC mobilization from bone marrow to peritoneal …

Epigenetic And Purinergic Regulation Of Mast Cells Mediator Release, Zahraa Abdulmohsin Mohammed

Theses and Dissertations

Mast cells (MCs) are well known for their implications in allergic reactions. They are also known to have multiple functions in the innate and adaptive immune system. Their activation plays an essential role in many aspects of physiological and pathological conditions. Allergies are considered chronic conditions that affect more than 60 million people in the U.S. These diseases are driven by the activation of MCs in response to IgE-mediated antigen, rendering these cells as targets for the management of allergies and asthma. Therefore, this research considers the understanding of their activation and the regulation of their response to be an …