Doctor of Philosophy, The Ohio State University, 2018, Electrical and Computer Engineering

Microcontroller Units (MCUs) are central and essential to many consumer electronic and industrial applications, including communication systems, automotive, and Internet of Things (IoT). Since, these MCUs can be used in various applications with different operating conditions, designing the internal power supply of such MCUs is quite challenging. For example, in some applications the MCUs could be powered from a Li-ion battery while in other application it could be powered from on-board regulator, or even an AC-to-DC adapter. This indeed requires the internal power supply of such MCUs to handle a very wide range of input voltages. In addition, these MCUs typically contains analog and digital circuits that operates from different supply levels. As a result, the internal power supply of the MCU has also to support a wide range of output voltage instead of designing separate power supply for each block which requires additional design and layout efforts. Moreover, depending on the performance requirements of the MCU or the mode of operation, the current consumption can vary very widely. It can be as high as 150-300 mA in active and high performance mode or it can be as low as 10-200 µA in sleep or idle mode. Consequently, the internal power supply of the MCU has to support a wide range of load currents. It is important to mention that since MCUs usually stay more than 50% of their time in sleep mode, the efficiency of their internal power has to be high not only in active mode (heavy load condition), but also in sleep mode (ultra-light load condition). Furthermore, each application puts different limitations and constrains on the passives (i.e. inductors or capacitors) used with the MCU. This includes different size and cost which exaggerate the constrains of the MCU's internal power supply which has to support a very wide range of passive components as well. Most importantly, since some low-noise MCUs usually contain noise sensitive IPs such as PLLs, Oscillators, and (open full item for complete abstract)

Committee: Ayman Fayed (Advisor); Patrick Roblin (Committee Member); Steven Bibyk (Committee Member) Subjects: Electrical Engineering

Doctor of Philosophy, Case Western Reserve University, 2024, Pharmacology

Cardiac contractility, essential to maintaining proper cardiac output and circulation, is regulated by G protein-coupled receptor (GPCR) signaling. Previously, the absence of regulator of G protein signaling (RGS) 2 and 5, separately, was shown to cause G protein dysregulation, contributing to modest blood pressure elevation and exaggerated cardiac hypertrophic response to pressure-overload. Whether RGS2 and 5 redundantly control G protein signaling to maintain cardiovascular homeostasis is unknown. Here we examined how the dual absence of RGS2 and 5 (Rgs2/5 dbKO) affects cardiac structure and function. Rgs2/5 dbKO male mice display left ventricular dilatation and impairment at baseline as measured by echocardiography, as well as reduced contractile response to acute dobutamine infusion. Loss of RGS2 increases disorganization of the sarcomeric protein titin in isolated left ventricular cardiomyocytes (LVCM), potentially contributing to contractile impairment. Male Rgs2/5 dbKO mice are vulnerable to stress induced arrhythmias. Surgery-induced stress in male Rgs2/5 dbKO mice led to 75% mortality within 72–96 h. LVCM from Rgs2/5 dbKO male mice showed augmented Ca2+ transients and increased incidence of arrhythmia to electrical field stimulation (EFS) and activation of β-adrenergic receptors (βAR) with isoproterenol (ISO). Dual loss of RGS2 and 5 suppressed forskolin-induced cAMP production, which was restored by Gi/o inactivation with pertussis toxin which also reduced arrhythmogenesis during EFS or βAR stimulation. We hypothesized that left ventricular dilation in Rgs2/5 dbKO male mice was due to disruption of the coordinated activity of RGS2 and 5 resulting in increased sensitivity to βAR stimulation. To test this hypothesis, we challenged wild type (WT), Rgs2 KO, Rgs5 KO, and Rgs2/5 dbKO male mice with 3 days of ISO infusion. Left ventricular dilation induced by the loss of RGS2 and/or RGS5 was unaffected by ISO administration. ISO infusion in (open full item for complete abstract)

Committee: Patrick Osei-Owusu (Advisor); Beata Jastrzebka (Committee Chair); Marcin Golczak (Committee Member); Jeffrey Garvin (Committee Member); Julian Stelzer (Committee Member); Marvin Nieman (Committee Member) Subjects: Pharmacology

Doctor of Business Administration (D.B.A.), Franklin University, 2024, Business Administration

The Indian Gaming Regulatory Act (IGRA) of 1988 enabled Native American Tribes to operate high-stakes gambling casinos, leading to 244 Tribes participating in casino gaming by 2022 and generating $40.9 billion in gross gaming revenue. Tribal gaming regulators face the task of examining a range of complex factors to ensure effective regulation, which, while not aimed at profit generation, can have an indirect effect on casino profitability. This relationship underscores the shared practices between Tribal regulatory agencies and casino enterprises. Despite the critical role of these agencies, there is a noticeable gap in academic research on the regulatory practices and performance of Tribal Gaming Regulatory Agencies (TGRAs). This qualitative study investigates the factors influencing TGRA actions and practices, with the goal of supporting high-performance and quality regulatory outcomes. Adopting a qualitative approach, the study uses "Two-Eyed seeing," which combines Indigenous and Western perspectives through interviews with fourteen active Tribal Gaming Regulators (TGRs) across eight U.S. regional districts under the National Indian Gaming Commission's authority. The integration of Western academic research with Tribal regulators' insights aims to offer useful recommendations for TGRs working toward regulatory effectiveness. Keywords: Indigenous, Indian Gaming Regulatory Act, regulatory excellence, Tribal Gaming Regulator (TGR), Tribal Gaming Regulatory Agency (TGRA), Two-Eyed seeing (TES)

Committee: John Nadalin (Committee Chair); Steven Hess (Committee Member); Tonia Young-Babb (Committee Member) Subjects: Law; Management; Organizational Behavior

Doctor of Philosophy, The Ohio State University, 2021, Biomedical Engineering

Tissue engineered vascular grafts (TEVGs) hold great promise in the field of regenerative medicine due to their potential growth capacity. This is critical for pediatric patients with congenital defects requiring a vascular conduit because these vessels are able to remodel into a neovessel that can grow as the patients grow. A greater understanding of TEVG remodeling is needed for successful clinical transition. The next generation of TEVGs needs to be developed based on rational design by combining biological data with computational modeling. This dissertation highlights the work of achieving this goal. Large animal studies provide details how growth and remodeling (G&R) transform the scaffolds into neovessels, which is predicted using computational modeling. Variations in graft designs are examined in small animal studies to determine how initial physical properties can dictate G Finally, the lysosomal trafficking regulator (LYST) is shown to influence tissue healing which provides insight into potential targets to modulate G&R in regenerative medicine.

Committee: Christopher Breuer (Advisor); Heather Powell (Committee Member); David Dean (Committee Member); Andrea Tedeschi (Committee Member) Subjects: Biomedical Engineering; Biomedical Research

Doctor of Philosophy, The Ohio State University, 2021, Biomedical Sciences

Tissue engineered scaffolds and regenerative medicine-based therapeutics hold great potential for a growing patient population in need of alternative tissue replacements. The initial work of this dissertation is on efforts to improve the translational capability of tissue engineered vascular grafts (TEVGs) to the clinic. A challenge in translating our group's TEVGs, as well as is seen with other tissue engineered scaffolds, is balancing the host response where an appropriate amount of healthy neotissue is created and remodeled overtime replacing the biodegradable scaffold and avoiding complications such as graft thrombosis and stenosis. Approaches to optimize tissue engineered scaffolds for use in patients often focuses on material alterations, cell seeding, bioreactor growth, or drug/small molecule co-administration. Seeding our TEVGs with bone-marrow derived nucleated cells has proven to be an effective approach to minimize graft occlusion and alter neotissue development; however, the exact mechanism underlying this remains unclear. The initial focus of this dissertation sought to elucidate what effect interleukin-10, an anti-inflammatory cytokine, had on graft patency and neotissue development from cells seeded onto TEVGs, from the host TEVG recipient, and from a recombinant protein drug delivery. This work demonstrated interleukin-10 from the host was critical in maintaining TEVG patency. Another promising approach optimizing a thrombosis and stenosis resistant TEVG has been our group's investigations into a novel wound healing modulator known as the lysosomal trafficking (LYST) protein. The protein, encoded by the LYST gene, is poorly understood with much of existing information coming from observations into disease states and cellular dysfunction that occurs in presence of a LYST gene mutation. A notable cellular finding is the perniculear clustering of enlarged lysosomes in mutant LYST cells due to defects in lysosomal fusion/fission. We serendipitously (open full item for complete abstract)

Committee: Christopher Breuer (Advisor); Ginny Bumgardner (Committee Member); Ryan Roberts (Committee Member); David Dean (Committee Member) Subjects: Biomedical Engineering; Cellular Biology; Experiments; Histology; Immunology; Medicine

PhD, University of Cincinnati, 2020, Medicine: Systems Biology and Physiology

Crosstalk between environmental components and genetic factors is known to play a key role in the onset and progression of many diseases. Viral infections are known environmental factors for a multitude of diseases. However, our understanding of the underlying molecular mechanisms of host-viral interactions is not complete. Viruses can encode regulatory proteins that can alter the transcription of human genes. Although these viral transcriptional regulators (vTRs) are known to be involved in disease mechanisms, a thorough understanding of these mechanisms remains elusive. Epstein-Barr virus encodes several vTRs, including EBV nuclear antigen 2 (EBNA2), which is known to alter human B cell gene transcription levels. Previously, we have shown that up to half of the risk loci of seven autoimmune disorders are occupied by EBNA2 by analyzing publicly available EBNA2 ChIP-seq data. In this work, we explore the molecular mechanisms of EBNA2-dependent regulation of the human genome by examining gene expression, chromatin openness, and chromatin 3D looping structure in a Ramos human B cell line that was 1) uninfected, 2) infected with EBV lacking EBNA2, or 3) infected with EBV expressing EBNA2. We identified more than 400 EBNA2-dependent human gene expression changes, over 4,000 EBNA2 binding events, >3,000 regions that show alteration of EBNA2-dependent human chromatin accessibility, and >2,000 regions of EBNA2-dependent alteration of human chromatin looping. Integrative analysis shows that EBNA2-dependent chromatin alteration regions were highly enriched for autoimmune risk genetic variants. Our work also presents examples of allele-dependent binding of EBNA2 at autoimmune risk genetic variants including ZMIZ1 and CD80. Our work highlights the roles for EBNA2 in the alteration of human gene regulatory programs by rewiring the iii chromatin landscape. We further extend the scope of the study to all vTRs in human infecting species by providing the first (open full item for complete abstract)

Committee: Matthew Weirauch Ph.D. (Committee Chair); Christian Hong Ph.D. (Committee Member); Leah Kottyan Ph.D (Committee Member); William Miller Ph.D. (Committee Member); Tongli Zhang Ph.D. (Committee Member) Subjects: Bioinformatics

Doctor of Philosophy, The Ohio State University, 2018, Physics

Low-energy nuclear physics has seen a renaissance of activity recently with the advent of the nuclear effective field theory (EFT) approach, the power of renormalization group techniques, and advances in the computational cost-effectiveness and sophistication of quantum many-body methods. Nevertheless challenges remain in part from ambiguities of the nuclear Hamiltonian via regulator artifacts and the scaling of the many-body methods to heavier systems. Regulator artifacts arise due to a renormalization inconsistency in the nuclear EFT as currently formulated in Weinberg power counting, though their ultimate impact on nuclear observables is unknown at present. This results in a residual cutoff dependence in the EFT to all orders. We undertake an examination of these regulator artifacts using perturbative energy calculations of uniform matter as a testbed. Our methodology has found that the choice of regulator determines the shape of the energy phase space and that different regulators weight distinct phase space regions differently. Concerning many-body calculations, at present only phenomenological energy density functionals are able to solve for the full table of nuclides. However these functionals are currently unconnected to QCD and have no existing method for systematic improvement. A technique, the density matrix expansion (DME), is one way to add microscopic chiral physics into these energy functionals. We develop a new formulation of the DME using local coordinate space regulators and allow for explicit Delta isobars in the chiral potentials. The resulting functionals show systematic improvement order-by-order in the chiral expansion and have non-trivial improvements in nuclear binding energy residuals over the previous Skyrme state of the art. Furthermore, renormalization group methods have also proved quite successful at taming certain nonperturbative aspects of nuclear potentials. However at present a robust many-body power counting scheme for (open full item for complete abstract)

Committee: Richard Furnstahl (Advisor); Robert Perry (Committee Member); Michael Lisa (Committee Member); Junko Shigemitsu (Committee Member) Subjects: Nuclear Physics; Physics

Doctor of Philosophy, The Ohio State University, 2017, Electrical and Computer Engineering

With the increasing power and thermal limits in the computing industry, energy-efficient computing has become an urging necessity. Therefore, a surge of interest has been recently given to the concept of Near-Threshold Computing (NTC) as a potential candidate to realize energy-efficiency in computations. By operating at supply voltages near the transistor's threshold voltage, NTC promises significant energy savings with moderate performance loss, which can be compensated for through parallelism. However, NTC faces a few challenges that hinder its wide adoption. On top of these challenges are the harsh specifications required for the power management and delivery units. Specifically, a power converter in an NTC system is required to achieve high efficiency at high current densities and low output voltages while seamlessly integrated on-chip, which are all contradicting specifications. To tackle the problem of energy-efficient computing, this research work addresses the challenges of NTC, with focus on power delivery. To do so, first, the target application of NTC is investigated to acquire the basic understanding of its challenges, opening doors for innovations and solutions for these challenges. Based on this understanding, which reveals the importance of power delivery for NTC and defines the requirements on power converters, most of the work in this thesis will focus on Switched-Capacitor (SC) power converters, which are found to be the most suitable type of converters for NTC. Therefore, a detailed study and literature review of SC converters is carried out. This study provides an in-depth understanding of SC converters operation, mechanisms, and challenges. Specifically, it is demonstrated that the most advantageous characteristic of SC converters is their compatibility with CMOS integration, while the most challenging aspect is their limited current density. Consequently, this thesis sets forth to address this challenge and proposes two solutions to boost t (open full item for complete abstract)

Committee: Waleed Khalil (Advisor) Subjects: Electrical Engineering

Master of Science (MS), Wright State University, 2016, Biological Sciences

Serine-arginine-rich (SR) or SR-like splicing factors interact with exon junction complex proteins during pre-mRNA processing to promote mRNA packaging into mature messenger ribonucleoproteins (mRNPs) and to dictate mRNA stability, nuclear export, and translation. In this thesis, I examined if depletion of two homologous non-classical serine-arginine-rich (SR) splicing factors, Btf (BCLAF1) and TRAP150, impacts regulation of cell cycle regulator transcripts and mitosis. Previous work showed that depletion of these proteins by RNAi causes mitotic defects including chromosome misalignment in metaphase. However, since Btf and/or TRAP150 did not co-localize with mitotic structures during mitosis, I hypothesized that Btf and/or TRAP150 depletion affect mitosis indirectly through altered expression of mitotic regulator transcripts. My results indicated that Btf and TRAP150 are important for controlling the abundance of transcripts that encode mitotic regulators. My results also suggest that Btf and TRAP150 have increased effects in maintaining the alignment of chromosomes at metaphase, as co-depletion of Btf and TRAP150 showed increased effects on the misalignment of chromosomes, thus demonstrating an important role in mitotic progression. Future studies will determine if altered expression or processing of endogenous cell cycle regulator protein transcripts is a result of changes in transcript distribution, and they will tease apart the molecular mechanisms underlying defective mitotic chromosome alignment/segregation in absence of Btf and TRAP150.

Committee: Paula Bubulya Ph.D. (Advisor); Katherine Excoffon Ph.D. (Committee Member); Labib Rouhana Ph.D. (Committee Member) Subjects: Biology

Doctor of Philosophy (PhD), Ohio University, 2016, Biological Sciences (Arts and Sciences)

Shigella is a genus of Gram-negative pathogenic bacteria that causes shigellosis, a severe form of bacillary dysentery in human with an infectious dose of less than 100 cells. The global burden of shigellosis is estimated to be no less than 125 million infections, with the majority of both infection and resulting deaths occurring in children under the age of five. These facts, in combination with the lack of a vaccine or universally effective treatment makes understanding the molecular mechanisms underlying the pathophysiology of Shigella of utmost importance. To survive and successfully colonize in the host, bacterial pathogens regulate the expression of multiple virulence-associated factors in response to the changes of environmental cues. This study focused on two of the important virulence-associated processes in the infections of S. dysenteriae, the most virulent species in the genus of Shigella: 1) acquisition of essential nutritional iron via the Shigella heme uptake (Shu) system from the iron-limited environment within the human host, and 2) secretion of effector proteins required for the invasion processes through the type III secretion system (T3SS). Investigations presented here identify the host-associated environmental factors that regulate the expression of the specific factors required to complete the processes listed above, and characterize the molecular mechanisms underlying each regulation. Specifically, studies focused on the regulation of the Shu system demonstrate that its periplasmic binding component, ShuT, is subject to iron-dependent transcriptional regulation via the activity of the global transcriptional regulator Fur, and temperature-dependent post-transcriptionally mediated by an RNA thermometer located within the 5' untranslated region of the gene. Studies focused on the regulation of MxiG, a component of the T3SS, identify and characterize a functional RNA thermometer that mediates post-transcriptional temperature-dependent regulation. (open full item for complete abstract)

Committee: Erin Murphy (Advisor); Jennifer Hines (Committee Chair); Peter Coschigano (Committee Member); Tomohiko Sugiyama (Committee Member); Donald Holzschu (Committee Member) Subjects: Biology; Microbiology

Master of Science in Biomedical Sciences (MSBS), University of Toledo, 2016, Biomedical Sciences (Bioinformatics and Proteomics/Genomics)

Global regulators each control hundreds of genes in bacteria, and it is still unclear how these regulators evolve, especially considering that gene regulation changes more rapidly than the regulated genes themselves. Leucine-responsive regulatory protein (Lrp) is a global regulator in enteric bacteria, controlling both metabolic and virulence-associated genes. Lrp orthologs are found among both Bacteria and Archaea. Surprisingly, even within the phylum ¿-Proteobacteria, Lrp is a global regulator in some orders and a local regulator in others. This raises important questions about the evolution of Lrp functions. The way global regulators function is crucially important to bacterial physiology. This thesis presents studies on the evolution and regulation pattern of Lrp, carried out with the goal of providing insights into global regulators more generally. Two independent studies of Lrp were carried out. The first compared Lrp sequences from four bacterial orders within the ¿-Proteobacteria: Enterobacteriales, Vibrionales, Pasteurelalles, and Alteromonadales. AsnC was also analyzed in parallel for comparison, as it is a paralog of Lrp that in all known cases is a local regulator controlling a small number of genes. As expected, Lrp and AsnC sequences formed two distinct clusters diverging from a common ancestor. These each divided into subclusters representing the Enterobacteriales, Vibrionales, and Pasteurellales. However, the Alteromonadales did not yield unitary clusters for either Lrp or AsnC, in contrast to the expected order-specific clustering we observed with the control housekeeping genes for 16S rRNA and RNA polymerase subunit RpoB. Logo analysis was also used to compare Lrp and AsnC in these four orders, and clear sequence signatures were identified. Ultimately, the Logo analysis provided the testable hypotheses that the globally-acting Lrp orthologs have short conserved sequences (particularly at the two ends of the polypeptides), and that Alteromon (open full item for complete abstract)

Committee: Matson Jyl (Committee Chair); Blumenthal Robert (Committee Member); Federov Alexei (Committee Member) Subjects: Bioinformatics

Doctor of Philosophy, Case Western Reserve University, 2016, EECS - System and Control Engineering

The closed-loop optimal control of multiple model linear systems with unknown parameters is investigated. The Bellman equation is modified to include the discrete random variable of the system mode conditioned on the measurements, and is then used to determine the optimal state feedback or dynamic output feedback controllers. Dynamic programming with the modified Bellman equation is used to calculate the optimal cost with the dual covariance. The dual covariance quantifies the probing aspects of the controller and is demonstrated that the closed-loop state or dynamic output feedback controllers have the dual property for the discrete-time multiple model linear systems with unknown parameters studied in this work. Monte Carlo simulations are used to show that the closed-loop control with state or dynamic output feedback always performs better than controllers such as the Certainty Equivalence or DUL controllers. Finally, the direct discrete-time implementation of the dual dynamic output feedback controller developed in this work is applied to the control of the nonlinear F-16 aircraft. The dual regulator is designed for stability augmentation in the context of reconfigurable control using the multiple model formulation integrated with flight and propulsion to accommodate sensor, actuator, and engine faults. The design process is explained in the context of trim, linearization, calculation of the mode probabilities, and tuning of the Kalman filters and includes the implementation of a six-stage dual regulator with a bank of parallel Kalman filters. The flight simulation results are presented for cases such as speed and pitch rate sensor faults, 1.5% and 3% losses of elevator actuator power, and 4% loss of engine power during steady-state level flight of the nonlinear F-16 aircraft model.

Committee: Kenneth Loparo PhD (Advisor); Marc Buchner PhD (Committee Member); Vira Chankong PhD (Committee Member); Richard Kolacinski PhD (Committee Member) Subjects: Aerospace Engineering; Electrical Engineering

Doctor of Philosophy, The Ohio State University, 2014, Integrated Biomedical Science Graduate Program

Nontypeable Haemophilus influenzae (NTHi) are Gram-negative commensal bacteria that reside in the nasopharynx. NTHi can also cause multiple upper and lower respiratory tract diseases that include sinusitis, conjunctivitis, bronchitis, and otitis media. In numerous bacterial species the ferric uptake regulator (Fur) acts as a global regulator of iron homeostasis by negatively regulating the expression of iron uptake systems. However in NTHi strain 86-028NP and numerous other bacterial species there are multiple instances where Fur positively affects gene expression. It is known that many instances of positive regulation by Fur occur indirectly through a small RNA intermediate. However, no examples of small RNAs have been described in NTHi. Therefore we used RNA-Seq analysis to analyze the transcriptome of NTHi strain 86-028NPrpsL and an isogenic 86-028NPrpsLΔfur strain to identify Fur-regulated intergenic transcripts. From this analysis we identified HrrF, the first small RNA described in any Haemophilus species. Orthologues of this small RNA exist only among other Pasteurellaceae. Our analysis showed that HrrF is maximally expressed when iron levels are low. Additionally, Fur was shown to bind upstream of the hrrF promoter. RNA-Seq analysis was used to identify targets of HrrF which include genes whose products are involved in molybdate uptake, deoxyribonucleotide synthesis, and amino acid biosynthesis. The stability of HrrF is not dependent on the RNA chaperone Hfq. This study is the first step in an effort to investigate the role small RNAs play in altering gene expression in response to iron limitation in NTHi.

Committee: Robert Munson Jr. (Advisor); Brian Ahmer (Committee Chair); Dan Wozniak (Committee Member); John Gunn (Committee Member) Subjects: Microbiology

Doctor of Philosophy, The Ohio State University, 2014, Electrical and Computer Engineering

In recent years, with the explosive increase of the wireless communication and consumer electronics products, the advanced system solutions which have powerful computation capability and multi-functions are in great demand in the market. Among the various solutions, System on Chip (SoC) is being widely exploited due to the fact that it has the highest level of integration of a large quantity of reusable intellectual property (IP) blocks such as microprocessor, memory block, interface block, RF block, and power management blocks. The success of a SoC design mainly relies on the available reusable IP blocks provided by the IP vendors. Given the trusted reusable IP blocks, a SoC system can be delivered to the market in a very timely way. Therefore, both powerful computation capability with multi functions and great productivity can be implemented at the same time by using SoC. However, the quality assurance of the reusable IP blocks is vital to the successful SoC design. In this dissertation, we analyzed and developed trusted Low Dropout Regulator (LDO) models for intellectual property (IP) reuse aiming at system verification. The LDOs were designed with TI (Texas Instrument) Analog System Lab Kit (ASLK) Pro kit and verified by using TI TINA simulation tools. Based on the performance of the LDOs, high level models of the LDOs in MATLAB are given for initial system validation. In addition, the Verilog-AMS behavior models are presented to cover the full functions of the LDOs. The correctness and effectiveness of the models are verified under Cadence design environment. The proposed models not only satisfy the reusable IPs quality assurance for SoC application but also indicate the practical issues with the use of building component ICs from ASLK Pro kit. Therefore, they can be used as trusted reusable IP blocks for design and verification of SoC.

Committee: Steven Bibyk (Advisor); Wu Lu (Committee Member); Jin Wang (Committee Member) Subjects: Electrical Engineering

MS, University of Cincinnati, 2014, Engineering and Applied Science: Aerospace Engineering

Air-breathing hypersonic vehicles have the potential to provide global reach and affordable access to space. Recent technological advancements have made scramjet-powered flight achievable, as evidenced by the successes of the X-43A and X-51A flight test programs over the last decade. Air-breathing hypersonic vehicles present unique modeling and control challenges in large part due to the fact that scramjet propulsion systems are highly integrated into the airframe, resulting in strongly coupled and often unstable dynamics. Additionally, the extreme flight conditions and inability to test fully integrated vehicle systems larger than X-51 before flight leads to inherent uncertainty in hypersonic flight. This thesis presents a means to design vehicle geometries, simulate vehicle dynamics, and develop and analyze control systems for hypersonic vehicles. First, a software tool for generating three-dimensional watertight vehicle surface meshes from simple design parameters is developed. These surface meshes are compatible with existing vehicle analysis tools, with which databases of aerodynamic and propulsive forces and moments can be constructed. A six-degree-of-freedom nonlinear dynamics simulation model which incorporates this data is presented. Inner-loop longitudinal and lateral control systems are designed and analyzed utilizing the simulation model. The first is an output feedback proportional-integral linear controller designed using linear quadratic regulator techniques. The second is a model reference adaptive controller (MRAC) which augments this baseline linear controller with an adaptive element. The performance and robustness of each controller are analyzed through simulated time responses to angle-of-attack and bank angle commands, while various uncertainties are introduced. The MRAC architecture enables the controller to adapt in a nonlinear fashion to deviations from the desired response, allowing for improved tracking performance, stabili (open full item for complete abstract)

Committee: Kelly Cohen Ph.D. (Committee Chair); Michael Bolender Ph.D. (Committee Member); Elad Kivelevitch Ph.D. (Committee Member) Subjects: Aerospace Materials

Master of Science, University of Toledo, 2014, Chemistry

The tuberculosis (TB) pandemic is responsible for 1.6 million deaths annually, most of which occur in developing nations. TB is treatable, though patient non-compliance, co-infection with HIV, and the long, 6-9 month treatment regimen have resulted in the emergence of drug-resistant TB. For these reasons, the development of novel anti-tuberculin drugs is essential. Three proteins – PhoR, PhoP, and MshC – of Mycobacterium tuberculosis (M.tb), the causative agent of TB, are the focus of this thesis. The PhoPR two-component system is a phosphorelay system responsible for the virulence of M.tb. The histidine kinase PhoR responds to a yet-unknown environmental stimulus and autophosphorylates a conserved histidine. The phosphate is transferred to an aspartate of the response regulator PhoP, which then forms a head-to-head homodimer and initiates the transcription of 114 virulence genes. Inhibiting PhoR or PhoP would rendered M.tb avirulent and increase its susceptibility to other drugs. For our PhoPR project, PhoR was separated into its extracellular (PhoRex) and intracellular (PhoRin) domains. We attempted to crystallize PhoRex and PhoRin, though currently no crystals have been achieved. Using the malachite green assay PhoRin was confirmed to spontaneously dephosphorylate. The DNA binding activity of PhoP was assessed using fluorescence polarization, though no binding was observed. To observe the complexation of PhoRin and PhoP, a pull-down method was developed using the non-hydrolyzable ATP analog, adenosine 5'-(ß,¿-imido)triphosphate (AMP-PNP). A stable PhoRin-AMP-PNP-PhoP complex was not identified. Future work is necessary for the crystallization of PhoRex and PhoRin. A new DNA binding assay is also necessary to elucidate PhoP kinetics. Obtaining these data will give significant insight to potential inhibitors for these proteins. Mycothiol is the low molecular weight thiol responsible for protection against oxidative stress and electrophilic toxins in actinomy (open full item for complete abstract)

Committee: Donald Ronning Dr. (Committee Chair); John Bellizzi Dr. (Committee Member); Ronald Viola Dr. (Committee Member) Subjects: Biochemistry; Chemistry

Master of Science, The Ohio State University, 2012, Electrical and Computer Engineering

This thesis presents work on the design of 1.5V, 100mA low-dropout (LDO) regulators with fast transient responses in the IBM8HP 0.13μm BiCMOS process. A conventional LDO architecture intended for use in an RF system was implemented and measured. The design of a printed circuit board (PCB) that is capable of measuring all pertinent characteristics of the regulator is also presented. Measurements show that the conventional design achieves a recovery time of less than 100ns with output voltage variations of less than 50mV. In addition to the conventional design, a new output capacitor-free architecture is introduced that can be fully integrated onto a chip. Simulations show that the output capacitor-free design achieves a recovery time of less than 50ns with output voltage variations of less than 140mV.

Committee: Dr. Steven Bibyk PhD (Advisor); Dr. Waleed Khalil PhD (Committee Member) Subjects: Electrical Engineering

Master of Science, The Ohio State University, 2012, Electrical and Computer Engineering

Field-programmable gate arrays (FPGAs) are used in a wide variety of applications and end markets, including digital signal processing, medical imaging, and high-performance computing. This thesis outlines the issues related to powering FPGAs. Supplying and conditioning power are the most fundamental functions of an electrical system. A loading application, be it an FPGA, cannot sustain itself without energy, and cannot fully perform its functions without a stable supply. The fact is transformers, generators, batteries, and other offline supplies incur substantial voltage and current variations across time and over a wide range of operating conditions. They are normally noisy and jittery not only because of their inherent nature but also because high power switching circuits like central processing units (CPUs) and digital signal processing (DSP) circuits usually load it. These rapidly changing loads cause transient excursions in the supposedly noise free supply, the end results of which are undesired voltage droops and frequency spurs where only a dc component should exist. The main component of a power supply is a voltage regulator. The role of the voltage regulator is to convert these unpredictable and noisy supplies to stable, constant, accurate, and load independent voltages, attenuating these ill fated fluctuations to lower and more acceptable levels. Linear or switching regulators based power supplies will be proposed and simulated. Today's FPGAs tend to operate at lower voltages and higher currents than their predecessors. Consequently, power supply requirements may be more demanding, requiring special attention to features deemed less important in past generations. Failure to consider the output voltage, sequencing, power-on, and soft start requirements can result in unreliable power-up or potential damage to FPGAs.

Committee: Joanne Degroat PhD (Committee Chair); Yuan Zheng PhD (Committee Co-Chair) Subjects: Electrical Engineering

Doctor of Philosophy, The Ohio State University, 2008, Electrical and Computer Engineering

Hypersonic air-breathing vehicles are a promising and cost-efficient technology for launching low-earth-orbit satellites and providing rapid global-response capabilities. Modeling and control of such vehicles has been an active subject of research in recent years. A first-principle, physics-based model (FPM) of the vehicle's longitudinal dynamics has been developed at the Air Force Research Laboratory, and made available to the academic community for control systems design. This model, while suitable for simulation, is intractable for model-based control, thus requiring further control-oriented modeling. A typical control objective is to track a velocity and altitude reference while maintaining physical feasibility of the control input and the state. Two control strategies are presented in this work. The first is a linear time invariant (LTI) design based on a novel formulation of a robust servo-mechanism using singular perturbation arguments. This approach does not rely on state reconstruction but does require an analysis of a family of linearized models from the FPM. The second design relies on reduced-complexity modeling of the FPM. Intractable expressions of the forces and moment in the FPM are replaced with a curve-fit model (CFM). The CFM is expressed as a linear parameter varying (LPV) system, where the scheduling variables depend on the system output. A novel LPV regulator design methodology is developed, which explicitly addresses the case of over-actuated models (i.e., models with more inputs than performance outputs). This is a non-trivial extension of the analysis and design of output regulators for LTI systems. The LPV regulator separates the control problem into a steady-state controller and a stabilizing controller. The steady-state controller produces a non-unique approximate steady-state using receding horizon constrained optimization, while the stabilizer renders the steady-state attractive. The steady-state controller represents an approach to add (open full item for complete abstract)

Committee: Andrea Serrani PhD (Advisor); Stephen Yurkovich PhD (Committee Member); Kevin Passino PhD (Committee Member) Subjects: Electrical Engineering; Engineering

Master of Science in Electrical Engineering, Cleveland State University, 2007, Fenn College of Engineering

NASA Glenn Research Center is developing various circuits for a lunar concept rover powered by both a stirling convertor and lithium ion batteries. To begin, a survey of six analog, non-power factor correcting controllers was done for an Advanced Stirling Convertor (ASC) design; one was selected to control the stirling convertor. Next, a constant power circuit and lithium ion battery charger was designed, built and tested based on simulation in PSpice. The constant power circuit enables the stirling convertor to maintain a constant power when additional power is required from the batteries.

Committee: Dan Simon (Advisor) Subjects: