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Thermally Assisted Pulsed Electric Field Ablation For Cancer Therapy, James Michael Hornef

Biomedical Engineering Theses & Dissertations

Pulsed Electric Fields (PEF) have promised improved treatment results in a variety of cancer types including melanoma, pancreatic and lung squamous cancer. Recent studies show that PEF-based cancer therapy may be improved further with the assistance of moderate heating of the target. Experiments were performed to design, calibrate and implement a feedback-looped infrared laser irradiation system that could maintain specified temperatures during the treatment. The exact treatment area, penetration depth and thermal distribution of a 980-nm laser fiber were quantified using several methods, including the knife-edge technique and a tissue optical property study. In vivo and in vitro experiments using …

A Correlational Study Of Sansec Sensors’ Electric Field Distribution On Lightning Attachment, Kayla M. Farrow

Electrical & Computer Engineering Theses & Dissertations

Old Dominion University and the National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC) Aviation Safety Program Atmospheric Environmental Safety Technologies Project team conducted research in using SansEC (Sans Electric Connection) sensors to provide lightning strike protection (LSP) and damage mitigation for composite aircraft. SansEC sensors are simplistic devices consisting of an open circuit conductive trace, shaped in a planar geometric spiral [1], [2], [3]. SansEC sensors can be designed in various shapes and sizes depending on the application. For applications on exterior aircraft surfaces, the sensor must be designed to perform the required lightning strike protection [1], [3]. …

Diffusion Modeling Of Impurities Through The Molybdenum Back Contact Of Cigs Solar Cells, Chinedum John Akwari

Electrical & Computer Engineering Theses & Dissertations

CIGS is a major technology in photovoltaics and depends heavily, as any other PV technology, on the capacity to achieve the highest efficiency possible to compete on the market. Alkaline elements, notably sodium and potassium, play a key role in this matter as they enhance the open circuit voltage and the fill factor of the CIGS solar cells. However, this effect exists only for very specific concentration of sodium and potassium. These impurities typically diffuse through the soda-lime glass substrate.

Via modeling of the SIMS data, we try to understand and predict the diffusion mechanisms of these impurities from the …

Study Of Modified Deposition Process For Cu(In,Ga)Se2 Solar Cell Back Contact, Tasnuva Ashrafee

Electrical & Computer Engineering Theses & Dissertations

As the worldwide demand for renewable energy is increasing, growth of the global share of alternative energy sources would improve overall energy security as well as bring environmental benefits. So far, solar cells - the devices that convert direct sunlight into electricity - are dominated by silicon devices. Another alternative is thin film solar cell, whose main inspiration is to reduce the electricity production cost. Cu(In, Ga)Se₂ (CIGS) solar cells are considered to have a great prospective because of reduced material and energy consumption during manufacturing. Many CIGS solar cell manufacturers are already exhibiting GW-scale production capacity. With the …

Enhancement Of Thermoelectric Properties Of Ald Synthesized Pbte And Pbse By Phonon Engineering, Xin Chen

Electrical & Computer Engineering Theses & Dissertations

Thermoelectrics is a green renewable energy technology that plays an important role in power generation due to its potential in generating electricity out of waste heat. The main challenge for the development of thermoelectrics is its low conversion efficiency. One key strategy to improve conversion efficiency is focused on reducing the thermal conductivity of thermoelectric materials. In this thesis, the novel phononic engineering concept was implemented by conformal ALD deposition of PbTe, PbSe thermoelectric films, and PbTe/PbSe nanolaminates on patterned silicon substrates in order to improve the thermoelectric performance of the thermoelectric films. The silicon substrates were lithographically patterned with …

Virtual Substrate Synthesis For Low-Cost High Efficiency Iii-V, Sean J. Babcock

Electrical & Computer Engineering Theses & Dissertations

The use of the low-cost thin-film vapor-liquid-solid (TF-VLS) method in the manufacturing of III-V solar cell substrates has the potential to provide a lightweight, flexible, and cheaper alternative to traditional III-V substrates typical of state-of-the- art power generation technology. The TF-VLS process has been shown to produce high optoelectronic quality polycrystalline InP on lightweight flexible metal foils. In this work, this novel method is applied to the growth of binary and ternary III-V materials which include: InP, InAs, and InGaP on Mo foils and/or sputtered Mo on Si wafers.

As a result of InP trials, powder XRD measurements have identified …

The Efficacy Of Programming Energy Controlled Switching In Resistive Random Access Memory (Rram), David Malien Nminibapiel

Electrical & Computer Engineering Theses & Dissertations

Current state-of-the-art memory technologies such as FLASH, Static Random Access Memory (SRAM) and Dynamic RAM (DRAM) are based on charge storage. The semiconductor industry has relied on cell miniaturization to increase the performance and density of memory technology, while simultaneously decreasing the cost per bit. However, this approach is not sustainable because the charge-storage mechanism is reaching a fundamental scaling limit. Although stack engineering and 3D integration solutions can delay this limit, alternate strategies based on non-charge storage mechanisms for memory have been introduced and are being actively pursued.

Resistive Random Access Memory (RRAM) has emerged as one of the …

Speech Based Machine Learning Models For Emotional State Recognition And Ptsd Detection, Debrup Banerjee

Electrical & Computer Engineering Theses & Dissertations

Recognition of emotional state and diagnosis of trauma related illnesses such as posttraumatic stress disorder (PTSD) using speech signals have been active research topics over the past decade. A typical emotion recognition system consists of three components: speech segmentation, feature extraction and emotion identification. Various speech features have been developed for emotional state recognition which can be divided into three categories, namely, excitation, vocal tract and prosodic. However, the capabilities of different feature categories and advanced machine learning techniques have not been fully explored for emotion recognition and PTSD diagnosis. For PTSD assessment, clinical diagnosis through structured interviews is a …

Investigation Of Low Cost Substrate Approaches For Iii-V Solar Cells, Marlene Lydia Lichty

Electrical & Computer Engineering Theses & Dissertations

With the need for cleaner energy sources, which can displace fossil fuel, the solar cell industry is of particular interest due to the abundancy of the Sun. Silicon currently dominates terrestrial applications, but efficiency improvements have saturated. III-V based solar cells have reported the highest efficiencies, however, high costs due to substrates and fabrication processes have limited these devices to specialty applications, such as space. In order to reduce the cost associated with fabricating III-V semiconductor substrate material, two different approaches were taken in this work with a particular focus on making III-Vs more applicable outside of specialty applications, including …

Recurrent Neural Networks And Matrix Methods For Cognitive Radio Spectrum Prediction And Security, Alexander M. Glandon

Electrical & Computer Engineering Theses & Dissertations

In this work, machine learning tools, including recurrent neural networks (RNNs), matrix completion, and non-negative matrix factorization (NMF), are used for cognitive radio problems. Specifically addressed are a missing data problem and a blind signal separation problem. A specialized RNN called Cellular Simultaneous Recurrent Network (CSRN), typically used in image processing applications, has been modified. The CRSN performs well for spatial spectrum prediction of radio signals with missing data. An algorithm called soft-impute for matrix completion used together with an RNN performs well for missing data problems in the radio spectrum time-frequency domain. Estimating missing spectrum data can improve cognitive …

Modification Of Deposition Process Parameters For Uniform Indium Layer Deposition, Isaac Butt

Electrical & Computer Engineering Theses & Dissertations

The need for more efficient light to energy converting cells has long been a subject of research and development. With abundant availability of solar energy that the earth receives, the photovoltaic industry has sought materials that could serve the purpose of great energy conversion. The photovoltaic industry is mainly dominated by Silicon owing to its abundant availability, reliability and economic cost. However, due to limitations on efficiency improvements, some focus has shifted toward III-V based solar cells with a great potential for attaining higher efficiency and multi-junction applications. However, the cost of the III-V materials is extremely high due to …

Low Temperature Plasma For The Treatment Of Epithelial Cancer Cells, Soheila Mohades

Electrical & Computer Engineering Theses & Dissertations

Biomedical applications of low temperature plasmas (LTP) may lead to a paradigm shift in treating various diseases by conducting fundamental research on the effects of LTP on cells, tissues, organisms (plants, insects, and microorganisms). This is a rapidly growing interdisciplinary research field that involves engineering, physics, life sciences, and chemistry to find novel solutions for urgent medical needs. Effects of different LTP sources have shown the anti-tumor properties of plasma exposure; however, there are still many unknowns about the interaction of plasma with eukaryotic cells which must be elucidated in order to evaluate the practical potential of plasma in cancer …

Study Of A High-Efficient Wide-Bandgap Dc-Dc Power Converter For Solar Power Integration, Yashwanth Bezawada

Electrical & Computer Engineering Theses & Dissertations

This research focuses on the design and analysis of a Boost cascaded Buck-Boost (BoCBB) power converter with super high efficiency in electric power conversion. The BoCBB power converter is based on emerging wide-bandgap silicon-carbide (SiC) MOSFETs and Schottky diodes, which have only 1/6 times of power loss in traditional silicon power semiconductor devices. The BoCBB power converter can be widely applied in solar harvesting for the National Aeronautics and Space Administration (NASA), military bases and electric utilities, as well as high-power DC motor drives for the electric vehicles, robotics, and manufacturing and product lines.

This research analyzed the topology and …

A Study Of The Sensitivity Of Energy Conversion Efficiency To Load Variation In Class-E Resonant Power Inverter, Richard Samuel Jennings

Electrical & Computer Engineering Theses & Dissertations

In this thesis the sensitivity of energy conversion efficiency (ECE) and output power of a class-E resonant inverter under variable resistive and inductive load assignments is examined for wireless power transfer (WPT) applications. By performing simulation and mathematical analysis, it was found that the on-resistance of the switching device has minor effect on the design’s efficiency. Additional comparisons between the simulation and mathematical analysis show reasonable output power and ECE load variation performance for the design, but with unique load impedances where zero voltage switching (ZVS) and zero derivative switching (ZDS) are achieved. These comparisons also expose inaccurate mathematical assumptions. …

Deposition Of Silicon Thin Films By Ion Beam Assisted Deposition, Tejaswini Miryala

Electrical & Computer Engineering Theses & Dissertations

With the depletion of non-renewable energy sources owing to increasing demands, we need to develop renewable energy sources, which can replace them with cleaner energy sources. The solar industry is one of these renewable energies. In spite of having very high potential, harvesting solar energy has been a challenge due to the cost of solar cells. Silicon dominates the photovoltaic industry, but even this technology can accommodate great improvements. This can be done notably by finding low cost deposition techniques for the silicon. The main aim of this thesis is to form high-quality nanocrystalline silicon thin films with the help …