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Full-Text Articles in Engineering

Ism-Band Energy Harvesting Wireless Sensor Node, Fnu Naveed Dec 2023

Ism-Band Energy Harvesting Wireless Sensor Node, Fnu Naveed

Graduate Theses and Dissertations

In recent years, the interest in remote wireless sensor networks has grown significantly, particularly with the rapid advancements in Internet of Things (IoT) technology. These networks find diverse applications, from inventory tracking to environmental monitoring. In remote areas where grid access is unavailable, wireless sensors are commonly powered by batteries, which imposes a constraint on their lifespan. However, with the emergence of wireless energy harvesting technologies, there is a transformative potential in addressing the power challenges faced by these sensors. By harnessing energy from the surrounding environment, such as solar, thermal, vibrational, or RF sources, these sensors can potentially operate …


Characterization Of Highly Doped N-Type And P-Type Silicon Carbide Ohmic Contacts, Tanner Rice Dec 2023

Characterization Of Highly Doped N-Type And P-Type Silicon Carbide Ohmic Contacts, Tanner Rice

Graduate Theses and Dissertations

Silicon Carbide (SiC) is a rather new material that possesses unparalleled properties when compared to Silicon. Due to its larger band gap alongside other thermal properties, SiC can survive in hotter, more radiation intensive environments, whether that be within the crust of the earth or in the reaches of space. As a desirable semiconductor for these applications, CMOS is an especially important device due to its low power consumption. However, creating a good contact between the metal and semiconductor optimally requires two different metals for the n -type and the p-type semiconductor. This greatly increases the processing time, as separate …


Chip- And System-Level Reliability On Sic-Based Power Modules, Pengyu Lai Aug 2023

Chip- And System-Level Reliability On Sic-Based Power Modules, Pengyu Lai

Graduate Theses and Dissertations

The blocking voltage, switching frequency and temperature tolerance of power devices have been greatly improved due to the revolution of wide bandgap (WBG) materials, such as silicon carbide (SiC) and gallium nitride (GaN). Owing to the development of SiC-based power devices, the power rating, operating voltage, and power density of power modules have been significantly improved. However, the reliability of SiC-based power modules has not been fully explored yet. Thus, this dissertation focuses on the chip- and system-level reliability on SiC-based power modules. For chip-level reliability, this work focuses on on-chip SiC ESD protection devices for SiC-based integrated circuits (ICs). …


Partial Discharge Mitigation In Power Modules Using An Automation-Driven Design Rule Development Method, Shilpi Mukherjee Aug 2023

Partial Discharge Mitigation In Power Modules Using An Automation-Driven Design Rule Development Method, Shilpi Mukherjee

Graduate Theses and Dissertations

Power modules used for the conversion and conditioning of electrical power for applications like electric vehicles, more-electric aircraft, the power grid, etc., are largely designed manually by engineers. Design automation of power modules is starting to gain recognition as a timely and necessary alternative to intuitive manual design and fabrication. With increasing need for wide bandgap materials that can operate at higher voltages, and the need to make modules more compact, hazards like electrical breakdown are more likely. Partial discharge (PD) is a silent and invisible precursor to electrical breakdown. It is compounded with compaction, creating a potential for electrical …


A Real-Time Anpc Inverter Digital Twin With Integrated Design-For-Trust, Paulo Vitor Do Amaral Custodio Aug 2023

A Real-Time Anpc Inverter Digital Twin With Integrated Design-For-Trust, Paulo Vitor Do Amaral Custodio

Graduate Theses and Dissertations

The demand for renewable energy has increased over the last few years, and so has the demand for greater expectations within the energy market. This increasing trend has been accompanied by more significant usage of internet-connected devices (IoT), leading to critical electrical infrastructure being connected to the internet. Implementing internet connectivity with such devices and systems provides benefits such as improving the system's performance, facilitating irregularity and anomaly mitigation, and providing additional situational awareness for enhanced decision-making. However, enhancing the connected system with IoT introduces a drawback – a greater vulnerability to cyber-attacks. Cyber-attacks targeting critical infrastructure in the electrical …


Modeling & Small Signal Analysis Of Grid Forming Inverter, Kadesh Hepburn Aug 2023

Modeling & Small Signal Analysis Of Grid Forming Inverter, Kadesh Hepburn

Graduate Theses and Dissertations

There is a rising number of inverter-based resources (IBRs) being integrated with distribution systems are becoming a more common occurrence. With integration of IBRs inverters, power utilities are experiencing an increase of number of operations with regards to voltage and frequency support. To maintain grid stability and reliability, IBRs need to provide some of the services currently (or formerly) provided by synchronous generators. Interconnection standards, like the IEEE 1547. 2018 has include requirements for IBRs to have the capability to provide some of these services—such as frequency and voltage support—and the procurement and deployment of the services can be implemented …


Fabrication And Measurement Of Lt-Gaas Photoconductive Antennas And Arrays, Zachary Paul Uttley Aug 2023

Fabrication And Measurement Of Lt-Gaas Photoconductive Antennas And Arrays, Zachary Paul Uttley

Graduate Theses and Dissertations

This thesis presents the fabrication and measurement of LT-GaAs based terahertz (THz) photo conductive antennas (PCAs) and arrays. The LT-GaAs THz PCAs are fabricated to serve as reference devices to new 2D material black phosphorous (BP) based THz PCAs. The LT-GaAs and BP devices have identical metallic electrodes, allowing for a comparison of emitted THz intensity and bandwidth. All PCAs have been measured using an open bench pulsed time-domain spectroscopy (TDS) system with a usable bandwidth from 0.1-4 THz, pumped with a 780nm Ti:Sapphire femtosecond laser. The results have shown LT-GaAs devices outperforming BP devices in signal amplitude and bandwidth …


Optocoupler Integration Of Ltcc-Based Gate Driver In A Sic Power Module, Michael Oghenekome Otobo Aug 2023

Optocoupler Integration Of Ltcc-Based Gate Driver In A Sic Power Module, Michael Oghenekome Otobo

Graduate Theses and Dissertations

The growing demand for electrical energy in today’s industrialized economy has driven the need for innovative approaches to meet diverse application requirements. Notably, advancements have been made in the field of power electronic systems, as reliable power electronic converters are essential for managing multiple power sources and loads. However, the development of these systems poses challenges related to power device switching speed, system weight and size, and power losses. The integration of a gate driver into a SiC power module offers a solution to many of these challenges, thereby driving the advancement of electrical power density expansion. An LTCC-based gate …


Understanding Peripheral Blood Pressure Signals: A Statistical Learning Approach, Md Abul Hayat Aug 2023

Understanding Peripheral Blood Pressure Signals: A Statistical Learning Approach, Md Abul Hayat

Graduate Theses and Dissertations

Proper estimation of body fluid status for human or animal subjects has always been a challenging problem. Accurate and timely estimate of body fluid can prevent life threatening conditions under trauma and severe dehydration. The main objective of this research is the estimation, classification and detection of dehydration in human and animal subjects using peripheral blood pressure (PBP) signals. Peripheral venous pressure (PVP) and peripheral arterial pressure (PAP) signals have been investigated in this research. Both PVP and PAP signals are PBP signals. A dataset of PVP signals was collected using standard peripheral intravenous catheters from human subjects suffering from …


Achieving High Renewable Energy Integration In Smart Grids With Machine Learning, Yaze Li Aug 2023

Achieving High Renewable Energy Integration In Smart Grids With Machine Learning, Yaze Li

Graduate Theses and Dissertations

The integration of high levels of renewable energy into smart grids is crucial for achieving a sustainable and efficient energy infrastructure. However, this integration presents significant technical and operational challenges due to the intermittent nature and inherent uncertainty of renewable energy sources (RES). Therefore, the energy storage system (ESS) has always been bound to renewable energy, and its charge and discharge control has become an important part of the integration. The addition of RES and ESS comes with their complex control, communication, and monitor capabilities, which also makes the grid more vulnerable to attacks, brings new challenges to the cybersecurity. …


Double-Sided Cooled Power Modules For Electric Vehicles, Riya Paul Aug 2023

Double-Sided Cooled Power Modules For Electric Vehicles, Riya Paul

Graduate Theses and Dissertations

Double-sided cooled (DSC) power modules in conjunction with Silicon Carbide (SiC) power devices are expected to significantly elevate the performance of the next-generation electric vehicle power inverters. The double-sided cooling enables maximum heat dissipation, resulting in higher power density. SiC power devices, with their fast-switching speeds, reduce the power losses for higher efficiency. A half-bridge power module consisting of 13 mΩ 1.2 kV SiC devices is used for this work. A baseline DSC power module was designed, fabricated, and tested. This unique design uses truncated rectangular copper connection blocks for better heat dissipation from the device top side compared to …


Design Of A Sigma-Delta Adc In 65nm Cmos Process, Michael Lee Thompson Iii May 2023

Design Of A Sigma-Delta Adc In 65nm Cmos Process, Michael Lee Thompson Iii

Electrical Engineering Undergraduate Honors Theses

Analog and digital signals both play a vital role in electrical engineering and the technology of today. As the role of electrical and computer engineers becomes more deeply involved in the development of new technology, an understanding of how these signals are utilized, and what they represent, is a necessity. Due to the inherent limitations involved with analog signals, there is a need for these signals to be accurately and efficiently converted to digital signals for processing. The job of the analog-to-digital converter, or ADC, is to receive this analog input signal (voltage or current) and create a digital representation …


Analyzing Energy Use From Arkansas Public School Buildings, Oscar Morton May 2023

Analyzing Energy Use From Arkansas Public School Buildings, Oscar Morton

Biological and Agricultural Engineering Undergraduate Honors Theses

Energy is a key global resource in society and greenhouse gas (GHG) emissions related to the consumption of energy have detrimental effects on the planet. With energy consumption increasing, exponential population growth, and diminishing natural resources necessary for energy production, the relevance of energy efficiency is dramatically increasing. In this project, I analyzed energy usage data from a set of public school buildings from one school district in northwest Arkansas from 2018, before targeted energy efficiency practices were implemented, through 2022 to see if energy usage changed over this short period. The objectives of analyzing energy data were to determine …


Micro-Faraday Cage Design And Analysis For Rf Sensitive Components On An Ltcc Substrate In Hfss, Roberto Quezada May 2023

Micro-Faraday Cage Design And Analysis For Rf Sensitive Components On An Ltcc Substrate In Hfss, Roberto Quezada

Electrical Engineering Undergraduate Honors Theses

This thesis focuses on creating and testing two different simulation environments in HFSS and analyzing the effectiveness of a micro-Faraday Cage on the RF Sensitive component by exchanging the SMPS and RF Sensitive component with 25GHz Microstrip Patch Antennas. Modern integrated circuit board systems consist of components that can generate electromagnetic signals and components that may be sensitive to electromagnetic interference. A switched-mode power supply (SMPS) is one component capable of producing electromagnetic interference (EMI) through its fundamental and harmonic switching frequency. By using a Faraday Cage to shield the RF-sensitive element, it is possible to reduce its susceptibility to …


Simulating Dielectric Barrier Plasma Actuators With Varying Geometries, Cass Wiederkehr May 2023

Simulating Dielectric Barrier Plasma Actuators With Varying Geometries, Cass Wiederkehr

Mechanical Engineering Undergraduate Honors Theses

The idea of Ionic Wind Propulsion has long been a topic of research for whether or not it can be used as a practical power source for flight. MIT researchers proved in 2018 that a plane with zero moving parts powered by Ionic Wind Propulsion was possible, and sustained flight could work with an internal power supply. However, due to the thin wire electrodes required to generate the ion cloud that made such propulsion possible, large amounts of drag rendered the plane extremely inefficient and impractical. Dielectric Barrier Discharge Devices (DBDs) are being investigated as to whether they can serve …


Evaluation Of Dual Band J-Pole Antennas To Serve Drone-Mountable Ham Radio Repeater, Jeremiah Wimer May 2023

Evaluation Of Dual Band J-Pole Antennas To Serve Drone-Mountable Ham Radio Repeater, Jeremiah Wimer

Electrical Engineering Undergraduate Honors Theses

The portable “roll-up” Dual-Band J-pole antenna model (commonly referred to as DBJ-2) is found to be the most favorable J-pole antenna design for serving a drone-mountable ham radio repeater. In addition to being light in weight, inexpensive to construct, and weather-resilient, the DBJ-2 offers the greatest Standing Wave Ratio (SWR) in the Very High Frequency (VHF) and Ultra High Frequency (UHF) bands compared to the other J-pole antenna designs evaluated. Enclosed is a brief overview of antenna design theory, as well as an exploration of various other J-pole antenna designs, and a clear rationale for selecting the DBJ-2 antenna design …


Fabrication Of Black Phosphorus Terahertz Photoconductive Antennas, Nathan Tanner Sawyers May 2023

Fabrication Of Black Phosphorus Terahertz Photoconductive Antennas, Nathan Tanner Sawyers

Physics Undergraduate Honors Theses

Terahertz (THz) photoconductive antennas (PCAs) using 40nm thin-film flakes of black phosphorus (BP) and hexagonal boron nitride (hBN) have been shown computationally to be capable of THz emission comparable to those based on GaAs [2]. In this paper, I briefly describe the scientific and practical interest in THz emissions and explain what warrants research into black phosphorus as a photoconductive semiconductor in THz devices. Furthermore, I outline the basic principle of how these antennas work and mention alternative designs produced by other researchers in the past. Finally, I summarize the fabrication process of these antennas, as well as the measurements …


Modbus Rtu For Embedded Cyber Secure Inverter Controller, Brady Mcbride May 2023

Modbus Rtu For Embedded Cyber Secure Inverter Controller, Brady Mcbride

Graduate Theses and Dissertations

The Modbus communication protocol is a widely adopted communication standard in industrial control systems. This communication protocol is known for being reliable and straightforward to implement while being versatile in terms of its operating parameters while supporting multiple formats over various hardware infrastructures and architectures. Many intelligent devices such as Programmable Logic Controllers (PLCs), Human-Machine Interfaces (HMIs), Internet-of-Things (IoT), and various Operational Technologies (OT) utilize Modbus for their communication systems. These types of systems must communicate with each other through a standardized and central communication process. To support the integration of these modular systems, a Field-Programmable Gate Array (FPGA) can …


The Growth And Characterization Of Inn Quantum Dots Using Droplets Epitaxy In Mbe, Malak Refaei May 2023

The Growth And Characterization Of Inn Quantum Dots Using Droplets Epitaxy In Mbe, Malak Refaei

Graduate Theses and Dissertations

III-nitride semiconductor material systems offer great potential for next-generation optoelectronic devices due to their direct bandgaps, which vary from 0.7 eV (InN) to 3.5 eV (GaN) to 6.2 eV (AlN), as well as their other unique properties. InN has gained much less attention than GaN and AlN within this family of semiconductors due to its complicated low-temperature growth. However, the prediction that an InN quantum well on GaN can become a two-dimensional (2D) topological insulator has resulted in expanding the research interest in InN. At the same time, this renewed interest has begun to reveal that the formation of an …


Design Approaches To Enhance Power Density In Power Converters For Traction Applications, Shamar Christian May 2023

Design Approaches To Enhance Power Density In Power Converters For Traction Applications, Shamar Christian

Graduate Theses and Dissertations

This dissertation presents a design strategy to increase the power density for automotive Power Conversion Units (PCUs) consisting of DC-DC and DC-AC stages. The strategy significantly improves the volumetric power density, as evident by a proposed PCU constructed and tested having 55.6 kW/L, representing an 11.2 % improvement on the Department of Energy’s 2025 goal of 50 kW/L for the same power electronics architecture. The dissertation begins with a custom magnetic design procedure, based on optimization of a predetermined C-core geometrical relationship and custom Litz wire. It accounts for electrical and thermal tradeoffs to produce a magnetic structure to best …


Multiple Output Power Supply Using Toroidal Transformers For Medium Voltage Active Gate Drivers, Samhitha Venkata Machireddy May 2023

Multiple Output Power Supply Using Toroidal Transformers For Medium Voltage Active Gate Drivers, Samhitha Venkata Machireddy

Graduate Theses and Dissertations

When operating in high power applications, power devices dissipate tens or hundreds of watts of power in the form of heat. The ability of the power devices to withstand power and dissipation of heat across the power devices becomes a prominent requirement in designing the power converter. This challenge demands a power converter design to be more effective and consistent which factors in size, cost, weight, power density and reliability. This study aims to propose a gate driver isolated power supply design that can be used in medium voltage applications (e.g., up to 10 kV) while respecting the principle of …


Stream Processor Development Using Multi-Threshold Null Convention Logic Asynchronous Design Methodology, Wassim Khalil May 2023

Stream Processor Development Using Multi-Threshold Null Convention Logic Asynchronous Design Methodology, Wassim Khalil

Graduate Theses and Dissertations

Decreasing transistor feature size has led to an increase in the number of transistors in integrated circuits (IC), allowing for the implementation of more complex logic. However, such logic also requires more complex clock tree synthesis (CTS) to avoid timing violations as the clock must reach many more gates over larger areas. Thus, timing analysis requires significantly more computing power and designer involvement than in the past. For these reasons, IC designers have been pushed to nix conventional synchronous (SYNC) architecture and explore novel methodologies such as asynchronous, self-timed architecture. This dissertation evaluates the nominal active energy, voltage-scaled active energy, …


Analysis Of An Isolated Bidirectional Ćuk Converter, Yeny Hau Chen May 2023

Analysis Of An Isolated Bidirectional Ćuk Converter, Yeny Hau Chen

Graduate Theses and Dissertations

The objective of this thesis is to perform an analysis of the isolated bidirectional Ćuk dc-dc converter topology and demonstrate the advantages and operation of this configuration through simulations using MATLAB/SimulinkTM and measurements collected from a 1.5-kW prototype tested at the Engineering Research Center (ENRC) laboratory of the University of Arkansas. The idea of integrating an active-clamp snubber circuit on each side of the converter, proposed by Dr. Sudip Mazumder from the University of Illinois, Chicago, limits the additional voltage stresses on the components due to the energy from the transformer’s leakage inductance. This is studied in this thesis to …