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Full-Text Articles in Engineering

Permanently-Installed Distributed Pressure Sensors For Downhole Applications, Xuran Zhu Dec 2022

Permanently-Installed Distributed Pressure Sensors For Downhole Applications, Xuran Zhu

All Dissertations

Technology advancements (e.g., hydraulic fracturing and horizontal drilling) to recover unconventional oil and gas (UOG) resources are critical in maintaining future U.S. oil and gas production levels. Permanently installed distributed downhole pressure sensors could monitor fracture propagation, assess the effectiveness of hydraulic fracturing, and optimize hydraulic fracturing placement so that overall UOG recovery efficiency can be increased. However, the harsh environment (high temperatures, high pressures, strong vibration, and presence of brine, mud, debris, hydrate, and various gases), the long data telemetry distance, and the requirements of reliability and service lifetime make the downhole monitoring a very challenging task. To combat …


Multi-Criteria Performance Evaluation And Control In Power And Energy Systems, Payam Ramezani Badr Dec 2022

Multi-Criteria Performance Evaluation And Control In Power And Energy Systems, Payam Ramezani Badr

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The role of intuition and human preferences are often overlooked in autonomous control of power and energy systems. However, the growing operational diversity of many systems such as microgrids, electric/hybrid-electric vehicles and maritime vessels has created a need for more flexible control and optimization methods. In order to develop such flexible control methods, the role of human decision makers and their desired performance metrics must be studied in power and energy systems. This dissertation investigates the concept of multi-criteria decision making as a gateway to integrate human decision makers and their opinions into complex mathematical control laws. There are two …


Sub-Bandgap Photon-Assisted Electron Trapping And Detrapping In Algan/Gan Heterostructure Field-Effect Transistors, Andrew Gunn Aug 2022

Sub-Bandgap Photon-Assisted Electron Trapping And Detrapping In Algan/Gan Heterostructure Field-Effect Transistors, Andrew Gunn

All Theses

We have investigated photon-assisted trapping and detrapping of electrons injected from the gate under negative bias in a heterostructure field-effect transistor (HFET). The electron injection rate from the gate was found to be dramatically affected by sub-bandgap laser illumination. The trapped electrons reduced the two-dimensional electron gas (2DEG) density at the AlGaN/GaN heterointerface but could also be emitted from their trap states by sub-bandgap photons, leading to a recovery of 2DEG density. The trapping and detrapping dynamics were found to be strongly dependent on the wavelength and focal position of the laser, as well as the gate bias stress time …


Miniaturized Battery Powered Air Quality Monitoring System, Bryan Chacon Aug 2022

Miniaturized Battery Powered Air Quality Monitoring System, Bryan Chacon

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In this work, an air quality monitoring system was developed using various sensors that measure specific air quality parameters, including Volatile Organic Compounds, Carbon Dioxide, particulate matter of varying sizes, ambient pressure, humidity, and temperature. This system is based off a Particle micro-controller, Boron LTE CAT-M1 which allows for cellular connectivity for real-time data transmission. It is powered by a 3.7 Volt Li-Po battery and has a miniaturized design which allows for portability. This data is processed through an Internet of Things software provider that allows for the device to be connected and accessed to and from anywhere in the …


An Evaluation Of Wi-Fi 802.11b Backscatter, Anthony Chen Aug 2022

An Evaluation Of Wi-Fi 802.11b Backscatter, Anthony Chen

All Theses

Internet of Things (IoT) devices are in need of low-power communications systems with longevity and reliability. With the use of backscatter technology, IoT devices can communicate at the cost of almost no power and can last for up to a decade. Furthermore, backscatter technology is compatible with everyday wireless signals such as Wi-Fi and Bluetooth, allowing for easy communication without specific hardware constraints. This thesis aims to evaluate a Wi-Fi backscatter system and analyze its ease in triggering off of such ambient signals and sources. The system will utilize Wi-Fi 802.11b as a backscatter source to trigger the backscatter system …


Hybrid Smart Transformer For Enhanced Power System Protection Against Dc With Advanced Grid Support, Moazzam Nazir Aug 2022

Hybrid Smart Transformer For Enhanced Power System Protection Against Dc With Advanced Grid Support, Moazzam Nazir

All Dissertations

The traditional grid is rapidly transforming into smart substations and grid assets incorporating advanced control equipment with enhanced functionalities and rapid self-healing features. The most important and strategic equipment in the substation is the transformer and is expected to perform a variety of functions beyond mere voltage conversion and isolation. While the concept of smart solid-state transformers (SSTs) is being widely recognized, their respective lifetime and reliability raise concerns, thus hampering the complete replacement of traditional transformers with SSTs. Under this scenario, introducing smart features in conventional transformers utilizing simple, cost-effective, and easy to install modules is a highly desired …


Embedding A Grid Of Load Cells Into A Dining Table For Automatic Monitoring And Detection Of Eating Events, Mohammad Mayyan Aug 2022

Embedding A Grid Of Load Cells Into A Dining Table For Automatic Monitoring And Detection Of Eating Events, Mohammad Mayyan

All Dissertations

This dissertation describes a “smart dining table” that can detect and measure consumption events. This work is motivated by the growing problem of obesity, which is a global problem and an epidemic in the United States and Europe. Chapter 1 gives a background on the economic burden of obesity and its comorbidities. For the assessment of obesity, we briefly describe the classic dietary assessment tools and discuss their drawback and the necessity of using more objective, accurate, low-cost, and in-situ automatic dietary assessment tools. We explain in short various technologies used for automatic dietary assessment such as acoustic-, motion-, or …