Engineering Commons^™

Nanostructured Surfaces Using Thermal Nanoimprint Lithography: Applications In Thin Membrane Technology, Piezoelectric Energy Harvesting And Tactile Pressure Sensing, Bhargav Pradip Nabar

Electrical Engineering Dissertations

Nanoimprint lighography (NIL) is emerging as a viable contender for fabrication of large-scale arrays of 5-500 nm features. The work presented in this dissertation aims to leverage the advantages of NIL for realization of novel Nano Electro Mechanical Systems (NEMS). The first application is a nanoporous membrane blood oxygenator system. A fabrication process for realization of thin nanoporous membranes using thermal nanoimprint lithography is presented. Suspended silicon nitried membranes were fabricated by Lowe-Pressure Chemical Vapor Deposition (LPCVD) in conjunction with a potassium hydroxide-based bulk michromachining process. Nanoscale features were imprinted into a commercially available thermoplastic polymer resist using a prefabricated …

Reliability Unit Commitment In Ercot Nodal Market, Hailong Hui

Electrical Engineering Dissertations

The Electric Reliability Council of Texas (ERCOT) is the independent system operator (ISO) that ensures a reliable electric grid and efficient electricity markets in the ERCOT region. ERCOT has successfully transited from a zonal market to an advanced nodal market since Dec. 2010. In the new ERCOT nodal wholesale market, a reliability unit commitment (RUC) process has been designed and implemented to ensure transmission system reliability and security. The main objective of RUC is to ensure that enough resource capacity, in addition to ancillary service capacity, is committed in the right locations to reliably serve the forecasted load in the …

A Low-Noise, Low-Power Cmos Amperometric Circuit For Glucose Sensing, Niranjan Karandikar

Electrical Engineering Dissertations

Diabetes is disorder associated with an insufficiency of insulin secretion. Large number of people around the world suffers from this disorder which can result into damages to eyes, kidneys, nerves and even death. One of the most common methods to detect the diabetes is to monitor the levels of glucose is the blood stream. Other biological fluids like tear fluid can also be used to detect levels of glucose. With emergence of MEMS technology several biosensors are developed, less invasive or non-invasive, which can detect these glucose levels from blood or tear. Central idea behind the developments of these biosensors …

Cmos Analog Correlator Based Glucose Sensor Readout Circuit, Varun K. Shenoy

Electrical Engineering Dissertations

Recent investigations show research and development of alternative methods of glucose sensing using electrochemical biosensors to help significantly reduce the difficulties associated with treating diabetes. The integration of microelectronic circuit technology with biosensors is generating greater research interest. The advantages of small size and less power consumption of integrated circuits (ICs) are helping with the realization of biosensors for improved performance. The major challenges involving designing of readout ICs for the electrochemical biosensors are accuracy and range. In this research work, an analog correlator based readout circuit for amperometric glucose electrochemical biosensors is designed and implemented. It is designed to …

Transfer-Printed Photonic Crystal Nanomembrane Fano Resonance Filters And Modulators, Yi-Chen Shuai

Electrical Engineering Dissertations

This dissertation presents the research work on photonic crystal nanomembrane Fano resonance devices based on transfer printing techniques. Ultra-compact high quality (Q) factor optical filters have been design, fabricated, and characterized based on single-layer and coupled double-layer photonic crystal slabs (PCS). Optical filters have also been designed and investigated for potentially high speed spatial lighting modulations. Fano resonance membrane reflectors with operation wavelength bands cover from near-infrared to mid and far-infrared have also been fabricated based on both reaction ion-etching and magnetic field guided metal-assisted chemical etching processes.Based on crystalline semiconductor nanomembrane transfer printing technique, we designed and experimentally demonstrated …

Cooperative Control Of Multi-Agent Systems; Stability, Optimality And Robustness, Kristian Hengster Movric

Electrical Engineering Dissertations

In this work design methods are given for distributed synchronization control of multi-agent systems on directed communication graphs. Conditions are derived based on the relation of the graph eigenvalues to a region in a complex plane that depends on the single-agent system and the solution of the local Riccati equation. The synchronizing region concept is used. Cooperative observer design, guaranteeing convergence of the local estimates to their true values, is also proposed. The notion of convergence region for distributed observers is introduced. A duality principle is shown to hold for distributed observers and controllers on balanced graph topologies. Application of …

Compressive Sensing For Wireless And Sensor Systems, Ji Wu

Electrical Engineering Dissertations

Compressive sensing (CS) is an emerging field based on the revelation that a small collection of linear projections of a sparse signal contains enough information for stable, sub-Nyquist signal acquisition. It provides a potential way to acquire the sparse data efficiently, or equivalently, highly accurate recovery of sparse data from undersampled measurements. Huffman coding and compressive sensing are adopted to compress real-world wind tunnel data. Both uniform and non-uniform Huffman coding are evaluated in terms of the number of quantization levels, mean square error, codeword length and compression ratio. The main drawback of Huffman coding is that it requires calculating …

Rf Power Amplifier And Oscillator Design For Reliability And Variability, Shuyu Chen

Electronic Theses and Dissertations

CMOS RF circuit design has been an ever-lasting research field. It gained so much attention since RF circuits have high mobility and wide band efficiency, while CMOS technology has the advantage of low cost and better capability of integration. At the same time, IC circuits never stopped scaling down for the recent many decades. Reliability issues with RF circuits have become more and more severe with device scaling down: reliability effects such as gate oxide break down, hot carrier injection, negative bias temperature instability, have been amplified as the device size shrinks. Process variability issues also become more predominant as …

On-Chip Electro-Static Discharge (Esd) Protection For Radio-Frequency Integrated Circuits, Qiang Cui

Electronic Theses and Dissertations

Electrostatic Discharge (ESD) phenomenon is a common phenomenon in daily life and it could damage the integrated circuit throughout the whole cycle of product from the manufacturing. Several ESD stress models and test methods have been used to reproduce ESD events and characterize ESD protection device's performance. The basic ESD stress models are: Human Body Model (HBM), Machine Model (MM), and Charged Device Model (CDM). On-chip ESD protection devices are widely used to discharge ESD current and limit the overstress voltage under different ESD events. Some effective ESD protection devices were reported for low speed circuit applications such as analog …

Ultrafast Laser Material Processing For Photonic Applications, Mark Ramme

Electronic Theses and Dissertations

Femtosecond Laser Direct Writing (FLDW) is a viable technique for producing photonic devices in bulk materials. This novel manufacturing technique is versatile due to its full 3D fabrication capability. Typically, the only requirement for this process is that the base material must be transparent to the laser wavelength. The modification process itself is based on non-linear energy absorption of laser light within the focal volume of the incident beam. This thesis addresses the feasibility of this technique for introducing photonic structures into novel dielectric materials. Additionally, this work provides a deeper understanding of the lightmatter interaction mechanism occurring at high …

Fiber Inline Pressure And Acoustic Sensor Fabricated With Femtosecond Laser, Yinan Zhang

Doctoral Dissertations

"Pressure and acoustic measurements are required in many industrial applications such as down-hole oil well monitoring, structural heath monitoring, engine monitoring, study of aerodynamics, etc. Conventional sensors are difficult to apply due to the high temperature, electromagnetic-interference noise and limited space in such environments. Fiber optic sensors have been developed since the last century and have proved themselves good candidates in such harsh environment. This dissertation aims to design, develop and demonstrate miniaturized fiber pressure/acoustic sensors for harsh environment applications through femtosecond laser fabrication. Working towards this objective, the dissertation explored two types of fiber inline microsensors fabricated by femtosecond …

Analysis And Design Optimization Of Multiphase Converter, Kejiu Zhang

Electronic Theses and Dissertations

Future microprocessors pose many challenges to the power conversion techniques. Multiphase synchronous buck converters have been widely used in high current low voltage microprocessor application. Design optimization needs to be carefully carried out with pushing the envelope specification and ever increasing concentration towards power saving features. In this work, attention has been focused on dynamic aspects of multiphase synchronous buck design. The power related issues and optimizations have been comprehensively investigated in this paper. In the first chapter, multiphase DC-DC conversion is presented with background application. Adaptive voltage positioning and various nonlinear control schemes are evaluated. Design optimization are presented …

Wavelength Scale Resonant Structures For Integrated Photonic Applications, Matthew Weed

Electronic Theses and Dissertations

An approach to integrated frequency-comb filtering is presented, building from a background in photonic crystal cavity design and fabrication. Previous work in the development of quantum information processing devices through integrated photonic crystals consists of photonic band gap engineering and methods of on-chip photon transfer. This work leads directly to research into coupled-resonator optical waveguides which stands as a basis for the primary line of investigation. These coupled cavity systems offer the designer slow light propagation which increases photon lifetime, reduces size limitations toward on-chip integration, and offers enhanced light-matter interaction. A unique resonant structure explained by various numerical models …

Learning Hierarchical Representations For Video Analysis Using Deep Learning, Yang Yang

Electronic Theses and Dissertations

With the exponential growth of the digital data, video content analysis (e.g., action, event recognition) has been drawing increasing attention from computer vision researchers. Effective modeling of the objects, scenes, and motions is critical for visual understanding. Recently there has been a growing interest in the bio-inspired deep learning models, which has shown impressive results in speech and object recognition. The deep learning models are formed by the composition of multiple non-linear transformations of the data, with the goal of yielding more abstract and ultimately more useful representations. The advantages of the deep models are three fold: 1) They learn …

Silicon Photonic Devices For Optical Delay Lines And Mid Infrared Applications, Saeed Khan

Electronic Theses and Dissertations

Silicon photonics has been a rapidly growing subfield of integrated optics and optoelectronic in the last decade and is currently considered a mature technology. The main thrust behind the growth is its compatibility with the mature and low-cost microelectronic integrated circuits fabrication process. In recent years, several active and passive photonic devices and circuits have been demonstrated on silicon. Optical delay lines are among important silicon photonic devices, which are essential for a variety of photonic system applications including optical beam-forming for controlling phased-array antennas, optical communication and networking systems and optical coherence tomography. In this thesis, several types of …

Differential Games For Multi-Agent Systems Under Distributed Information, Wei Lin

Electronic Theses and Dissertations

In this dissertation, we consider differential games for multi-agent systems under distributed information where every agent is only able to acquire information about the others according to a directed information graph of local communication/sensor networks. Such games arise naturally from many applications including mobile robot coordination, power system optimization, multiplayer pursuit-evasion games, etc. Since the admissible strategy of each agent has to conform to the information graph constraint, the conventional game strategy design approaches based upon Riccati equation(s) are not applicable because all the agents are required to have the information of the entire system. Accordingly, the game strategy design …

Modeling And Simulation Of All-Electric Aircraft Power Generation And Actuation, David Woodburn

Electronic Theses and Dissertations

Modern aircraft, military and commercial, rely extensively on hydraulic systems. However, there is great interest in the avionics community to replace hydraulic systems with electric systems. There are physical challenges to replacing hydraulic actuators with electromechanical actuators (EMAs), especially for flight control surface actuation. These include dynamic heat generation and power management. Simulation is seen as a powerful tool in making the transition to all-electric aircraft by predicting the dynamic heat generated and the power flow in the EMA. Chapter 2 of this dissertation describes the nonlinear, lumped-element, integrated modeling of a permanent magnet (PM) motor used in an EMA. …

Monolithically Integrated Broadly Tunable Light Emitters Based On Selectively Intermixed Quantum Wells, Abdullah Zakariya

Electronic Theses and Dissertations

A monolithically integrated broadly tunable MQW laser that utilizes a combined impurity-free vacancy disordering (IFVD) of quantum wells and optical beam steering techniques is proposed and investigated experimentally. The device consists of a beam-steering section and an optical amplifier section fabricated on a GaAs/AlGaAs quantum well (QW) p-i-n heterostructure. The beam steering section forms a reconfigurable optical waveguide that can be moved laterally by applying separately controlled electrical currents to two parallel contact stripes. The active core of the gain section is divided in into selectively intermixed regions. The selective intermixing of the QW in the gain section results in …

Optically Induced Forces In Scanning Probe Microscopy, Dana Kohlgraf-Owens

Electronic Theses and Dissertations

The focus of this dissertation is the study of measuring light not by energy transfer as is done with a standard photodetector such as a photographic film or charged coupled device, but rather by the forces which the light exerts on matter. In this manner we are able to replace or complement standard photodetector-based light detection techniques. One key attribute of force detection is that it permits the measurement of light over a very large range of frequencies including those which are difficult to access with standard photodetectors, such as the far IR and THz. The dissertation addresses the specific …

Polymer Optical Fibers For Luminescent Solar Concentration, Esmaeil Banaei

Electronic Theses and Dissertations

Luminescent solar concentrators (LSC’s) are promising candidates for reducing the cost of solar power generation. Conventional LSC’s are slab waveguides coated or doped with luminescence materials for absorption and guiding of light to the slab edges in order to convert optical energy into electricity via attached photovoltaic (PV) cells. Exploiting the advantages of optical fiber production, a fiber LSC (FLSC) is presented in this thesis, in which the waveguide is a polymeric optical fiber. A hybrid fiber structure is proposed for an efficient two-stage concentration of incident light, first into a small doped core using a cylindrical micro-lens that extends …

Fault Location In Power Networks Using Synchronized Phasor Measurements, Cuong Nguyen

Theses and Dissertations

Faults in electric power systems can lead to cascading power outages which cause tremendous loss to the economy and affect people’s lives. Technical reports of recent blackout events in the United States pointed out the lack of situational awareness as one of the main causes of widespread outages. Time synchronized phasor measurement is recommended as a technology that can improve the monitoring of power system condition. By knowing exactly where a fault occurs, necessary actions can be taken in a timely manner and thus, damage caused by that fault can be limited. In this thesis, first, a method for precise …

Resveratrol Attenuates The Development Of Trans-Aortic Constriction (Tac) Induced Heart Failure In Mice, Prakash Kumar Gupta

Theses and Dissertations

Heart failure (HF) still remains the leading cause of morbidity and mortality and imposes severe global affliction and enormous cost on the healthcare system. Although current pharmacological therapies have shown to slow down the progression of HF, but seems to have reached their limits in improving overall patient prognosis. Thus, an immediate call for novel alternate therapies are needed which act independently as well as in conjunction with current treatment modality. Studies were performed in the well-established transverse aortic constriction (TAC) model of chronic pressure overload (PO) in mice. In the first series of studies, Male C57BL6 mice (26-28 g) …

Emulation Of An Aeroderivative Twin-Shaft Gas Turbine Engine Using An Ac Electric Motor Drive, Blanca A. Correa

Theses and Dissertations

This dissertation presents a method to use an electric motor to emulate the steady-state and transient shaft power characteristics of an aeroderivative twin-shaft turbine engine. Model-based control provides the framework for developing an aeroderivative twin-shaft engine emulation system. Criteria are developed to appropriately specify the motor and variable-speed drive, based on torque, power, and inertia. This method accounts for the difference in inertia between the engine and the emulating motor; it establishes for the first time the nominal and peak torque requirements of the machine and the peak power and current requirements of the electronic motor drive (inverter).

Our results …

Modeling Of Sic Power Semiconductor Devices For Switching Converter Applications, Ruiyun Fu

Theses and Dissertations

Thanks to recent progress in SiC technology, SiC JFETs, MOSFETs and Schottky diodes are now commercially available from several manufactories such as Cree, GeneSiC and Infineon. SiC devices hold the promise of faster switching speed compared to Si devices, which can lead to superior converter performance, because the converter can operate at higher switching frequencies with acceptable switching losses, so that passive filter size is reduced. However, the ultimate achievable switching speed is determined not only by internal semiconductor device physics, but also by circuit parasitic elements. Therefore, in order to accurately predict switching losses and actual switching waveforms, including …

Development Of Proteomic Characterization And Speciation Techniques Utilizing Tryptic Peptides With Maldi-Tof Ms And Lc-Esi Ms-Ms, Jennifer Marie Kooken

Theses and Dissertations

The characterization of microbes which can be opportunists and pathogens (e.g., methicillin resistant Staphylococcus aureus (MRSA)) is important in understanding and potentially treating diseases caused by various bacterial species. Common genera found in the human skin micro-biome include Micrococcus and Staphylococcus, but there only a limited number of tests to differentiate these genera and/or species. My research reflects methods development from distinguishing one closely related genera from another and then expanded to species identification. Tryptic peptides were analyzed by MALDI TOF MS and the mass profiles compared with those of a reference strain in both genus and species identification. Aconitate …

Investigation Of Start Domain Proteins In Human Luteinized Cells And Cos-1 Cells, Bo Shi

Theses and Dissertations

After the luteinizing hormone surge of the menstrual cycle, the ovarian follicular granulosa and theca cells terminally differentiate to form the luteal cells of the corpus luteum. During this process known as luteinization, granulosa cells begin to synthesize large quantities of progesterone, a hormone essential for pregnancy. The rate limiting step for the de novo synthesis of pregnenolone (the precursor to progesterone) is the transport of cholesterol from the outer to the inner mitochondrial membrane, a process mediated by STARD1. STARD1 contains a C-terminal lipid binding domain holding one molecule of cholesterol, and an N-terminal domain targeting STARD1 to the …

Accelprint:Accelerometers Are Different By Birth, Sanorita Dey

Theses and Dissertations

This paper submits a hypothesis that smartphone accelerometers possess unique fingerprints. We believe that the fingerprints arise from hardware imperfections during the sensor manufacturing process, causing every sensor chip to respond differently to the same motion stimulus. The differences in responses are subtle enough that they do not affect most of the higher level functions computed on them. Nonetheless, upon close inspection, these fingerprints emerge with consistency, and can even be somewhat independent of the stimulus that generates them. Measurements and classification on 80 standalone accelerometer chips, 25 Android phones, and 2 tablets, show precision and recall upward of 96%, …

Accelerating Short Read Mapping Using A Dsp Based Coprocessor, Shaun I. Gause

Theses and Dissertations

Advances in next generation sequencing technologies have allowed short reads to be generated at an increasing rate, shifting the bottleneck of the sequencing process to the short read mapping computations. High costs and extended processing times drive researchers to pursue more efficient solutions with an overall goal of a short read mapping architecture capable of processing short reads as they are generated. Digital signal processors have shown high performance capabilities while maintaining low power consumption in a wide field of applications. This thesis explores the use of a DSP accelerated exact match short read mapping algorithm, focusing on a performance …

Multi-Label Segmentation Propagation For Materials Science Images Incorporating Topology And Interactivity, Jarrell Waggoner

Theses and Dissertations

Segmentation propagation is the problem of transferring the segmentation of an image to a neighboring image in a sequence. This problem is of particular importance to materials science, where the accurate segmentation of a series of 2D serial-sectioned images of multiple, contiguous 3D structures has important applications. Such structures may have prior-known shape, appearance, and/or topology among the underlying structures which can be considered to improve segmentation accuracy. For example, some materials images may have structures with a specific shape or appearance in each serial section slice, which only changes minimally from slice to slice; and some materials may exhibit …

Ultrawideband (Uwb) And Reconfigurable Antennas - New Concepts For Conformal Load Bearing Antenna Structures (Clas), Nicholas Bishop

Theses and Dissertations

Conformal antennas have been increasingly playing an important role in a vast number wireless of communication applications. More specifically, Conformal Load Bearing Antenna Structures (CLAS) have drawn a great deal of interest among researchers and engineers because of their advantages of multiple functionality, e.g. antenna and structure both. The objectives of this thesis are to investigate and design innovative conformal Ultrawideband (UWB) endfire antenna arrays and reconfigurable aperture coupled pixel patch antennas both of which are good candidates for CLAS. First, a broadband VHF-UHF end-fire Yagi-Uda array is proposed for possible air vehicle integration and operation within the 240-465 MHz …