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Design, Fabrication, And Characterization Of Advanced High-Power Single-Mode 9xxnm Semiconductor Lasers, Xiaolei Zhao

All Dissertations

This thesis presents the comprehensive design, fabrication, and demonstration of advanced high-power, high-efficiency single-mode semiconductor lasers operating at a wavelength of 9xxnm. We begin with the design of the laser epitaxial structure, serving as the cornerstone for achieving high-power high-efficiency lasers. Our methodology integrates a semi-analytical calculation model, which accounts for Longitudinal Spatial Hole Burning (LSHB) and Two-Photon Absorption (TPA) effects, facilitating a thorough exploration of how design parameters influence output power and conversion efficiency. This approach offers an effective and time-efficient epitaxial structure optimization strategy compared to conventional full 3D simulation models.

Subsequently, we demonstrate high-power, high-efficiency ridge waveguide …

The Contribution Of Micrornas To Rybp Silencing In Glioblastoma Multiforme, Alex B. Lee

Graduate Theses

Glioblastoma multiforme (GBM) is a highly aggressive and invasive tumor of the central nervous system (CNS). Survival rates are abysmal, with only 7.2% of patients alive 5-years after diagnosis. Because of this, understanding epigenetic alterations that give GBM tumors their aggressive phenotypes is critical for the development of more targeted and effective therapies. These alterations frequently affect a group of proteins called the Polycomb group proteins, which play important oncogenic and tumor suppressive roles in cancer. One Polycomb protein, the RING1- and YY1-binding protein (RYBP), is downregulated in a majority of GBM patients, suggesting a strong tumor suppressive property. In …

Mems Optical Cavities For Low Power Communication., Jacob Schopp

Electronic Theses and Dissertations

This thesis discusses the use of MEMS (microelectromechanical systems) optical cavities for use in low power communication. MEMS optical cavities are thin air gaps between an actuated MEMS mirror and a fixed glass encapsulation. By moving the MEMS mirror the reflectivity of the MEMS optical cavity can be changed. This change in reflectivity can be used to transmit information passively by modulating reflected light intensity instead of generating new light using a light source. These MEMS optical cavities are demonstrated using optical fibers for illumination delivery and reflected light collection. In addition to being reflected for communication, the illuminating light …

High Performance Silicon Carbide Based Converters For Powertrain Electrification, Nan Lin

Graduate Theses and Dissertations

With the increasing concern towards environment protection, electric vehicles (EVs) and hybrid electric vehicles (HEVs) have become popular in recent years. They not only help reduce carbon emissions, but also come with other benefits such higher efficiency and better user experience. Many countries and vehicle manufactures have made their plans to keep up with this trend in vehicle electrification. Powertrain is an assembly of components in a vehicle that pushes it forward. As for EVs and HEVs, their powertrains are composed of one or more power electronics converters, which are significant to the system. Silicon carbide MOSFETs have shown superior …

Design And Implementation Of High-Frequency Dc-Dc Converters For Ev Applications, Rahul Biswash

Graduate Theses and Dissertations

The power electronics industry has been revolutionized by introducing wide bandgap semiconductor devices, such as Silicon Carbide (SiC) and Gallium Nitride (GaN). Due to their high frequency, high temperature, and high voltage operating capabilities, wide bandgap devices boast significant improvements in power density, efficiency, and reliability, as evidenced by their ability to decrease the size of power converters by operating at higher frequencies, temperatures and voltages, use of smaller and less passive components, such as transformers, inductors and capacitors, which makes power converters more compact and light-weight, ideal for space and weight-constrained applications, and compatibility with a wide range of …

Vr Circuit Simulation With Advanced Visualization For Enhancing Comprehension In Electrical Engineering, Elliott Wolbach

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

As technology advances, the field of electrical and computer engineering continuously demands innovative tools and methodologies to facilitate effective learning and comprehension of fundamental concepts. Through a comprehensive literature review, it was discovered that there was a gap in the current research on using VR technology to effectively visualize and comprehend non-observable electrical characteristics of electronic circuits. This thesis explores the integration of Virtual Reality (VR) technology and real-time electronic circuit simulation with enhanced visualization of non-observable concepts such as voltage distribution and current flow within these circuits. The primary objective is to develop an immersive educational platform that makes …

An Investigation Of Information Structures In Dna, Joel Mohrmann

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

The information-containing nature of the DNA molecule has been long known and observed. One technique for quantifying the relationships existing within the information contained in DNA sequences is an entity from information theory known as the average mutual information (AMI) profile. This investigation sought to use principally the AMI profile along with a few other metrics to explore the structure of the information contained in DNA sequences.

Treating DNA sequences as an information source, several computational methods were employed to model their information structure. Maximum likelihood and maximum a posteriori estimators were used to predict missing bases in DNA sequences. …

Analyzing A Software Based Lossy Compression Algorithm On An Fpga Platform, Tripp Herlong

All Theses

In HPC, the ability to generate data is outpacing our hardware capabilities of storing said data. This presents the need for compression so we can keep important data preserved without costly hardware upgrades or worrying about hardware speed limitations. Traditional forms of compression are software based, which presents a speed issue that can lead to bottlenecks when storing data.Scientific data lossy compression methods such as SZ enable a speedup on memory transfer by simplifying computation to minimize the essential data size. SZx is a lightweight version of the popular SZ floating point compressor that may benefit from hardware acceleration. This …

4-Channel Spatially Multiplexed Communication System In Single-Core Optical Fibers, Ce Su

Theses and Dissertations

This dissertation delves into exploring and advancing spatial domain / space division multiplexing (SDM) technologies within single-core optical fibers, a frontier in optical fiber communications poised to meet the burgeoning global demand for data transmission. At the heart of this research is the pursuit to significantly enhance the capacity and efficiency of optical fiber communication systems without necessitating additional fiber infrastructure. This work unveils a new paradigm in optical fiber communications characterized by a pioneering 4-channel SDM system through a meticulous process encompassing theoretical modeling, computational simulations, design innovations, and rigorous experimental validations. Theoretical contributions include the development of refined …

Head Impact Measurement Using Piezoelectric Sensors, Huda Abdulla Alnuaimi

Theses

The importance of safety measures cannot be overstated, especially when it comes to protecting the human head. Head injuries can have severe, life-altering consequences, as the head is crucial for controlling the entire body. Unlike machines that store data, the human brain's capacity to retain thoughts and memories can be significantly affected by even a single injury. This thesis introduces a method for predicting the specific area of the head that might be injured during an impact. The prediction is based on the intensity and duration of the impact. The innovation of this thesis lies in the use of piezoelectric …

Ultra-Sensitive Visible-Ir Range Fiber Based Plasmonic Sensor: A Finite-Element Analysis And Deep Learning Approach For Ri Prediction, Mohammad Al Mahfuz, Sumaiya Afroj, Afiquer Rahman, Md. Azad Hossain, Md. Anwar Hossain, Md Selim Habib

Electrical Engineering and Computer Science Faculty Publications

In this paper, a relatively simple and ultra-sensitive Photonic crystal fiber (PCF) based surface plasmon resonance (SPR) sensor is proposed for detecting different analyte refractive indices (RIs) ranging from 1.33 to 1.43 over a wide range of wavelength spectrum spanning 0.55 μm to 3.50 μm. The comprehensive finite-element simulations indicate that it is possible to achieve remarkable sensing performances such as wavelength sensitivity (WS) and figure of merit (FOM) as high as 123,000 nm/RIU and 683 RIU^-1, respectively, and extremely low value of wavelength resolution (WR) about 8.13×10⁻⁷ RIU. A novel artificial neural network (ANN) model is …

Design And Optimization Of An Azeotropic Distillation Pilot Plant For The Production Of Pure Ethanol, Samwel V. Manyele

Tanzania Journal of Engineering and Technology (TJET)

This study aimed to design an azeotropic distillation plant using Aspen Plus® V10 software and determine optimal process conditions for producing pure ethanol greater than 95% from pre-concentrated near-azeotropic ethanol-water solution. The non-random two-liquid Redlich-Kwong thermodynamic model was the base method for property analysis and performance prediction. Modelling and simulation of the converged process were conducted for fixed column variables (R = 5, N = 12 and p = 1 atm). Plant operating parameters were varied in the range of 0 to 1 for the pre-heater vapour fraction, 2 to 10 for the column feed plates (NFP), 2 to 6 …

Optimization Pump As Turbine Coupled To A Self-Excited Induction Generator Using Multi-Objective Genetic Algorithm, Emanuel J. Nyirenda

Tanzania Journal of Engineering and Technology (TJET)

As a way of accelerating the deployment of affordable and clean renewable energy generation technologies, applying a pump working as a turbine coupled to a self-excited induction generator is gaining popularity in various areas including energy recovery and micro hydro systems. However, it is currently challenging to predict the performance of the PAT-SEIG system and there is no agreed-upon rule on the selection of the appropriate system to be installed at a particular site. This paper has presented multi-objective optimization to select the best operating point of the PAT-SEIG system. The results show that the peak efficiencies for the PAT …

Evaluation Of Cybersecurity In Remote Working Settings For Mobile Network Operators, Victoria Mahabi

Tanzania Journal of Engineering and Technology (TJET)

Cybersecurity has increasingly been a primary concern to people as technology advances and allows them to work remotely. This study thus evaluated the cybersecurity posture for organisations that have opted for remote working culture, whereas emerging cyber threats, practices to combat them, and appropriate guidelines for managing cyber threats were discussed. The study used a descriptive design with a quantitative approach from 118 information technology personnel working for Tanzania's three major mobile network operators (MNOs). SPSS analysed the collected data. The study revealed that predominant cyber-threats affecting MNOs in remote working include human errors, phishing attacks, malicious domains, denial of …

Sol-Gel Synthesis And Microstructure Characterization Of Nio-Tio2 Semiconductor, Godlisten N. Shao

Tanzania Journal of Engineering and Technology (TJET)

NiO-TiO2 is a fascinating p-n semiconducting binary metal oxide with unique electronic and optical properties. The NiO-TiO2 has been synthesized using complicated preparation methods and expensive precursors that hamper their large-scale production. The present study reports the preparation of NiO-TiO2 semiconductor with improved physicochemical properties. NiO-TiO2 samples were prepared through one-pot sol-gel synthesis process followed by sintering of the as-synthesized materials at temperatures ranging from 600 to 1000 °C. The role of thermal treatment and NiO content on the microstructures was exquisitely studied. The microstructure of the NiO-TiO2 samples was examined by Raman spectroscopy, XRD, XRF, SEM-EDAX, high resolution TEM, …

Optimal Load Shedding During Service Restoration In Electrical Secondary Distribution Network Based On Reinforcement Learning, Rukia J. Mwifunyi

Tanzania Journal of Engineering and Technology (TJET)

Increased stress in traditional power systems results in blackouts due to voltage instability attributed to a mismatch between available capacity and load demand, especially in distribution networks. Service restoration schemes are designed to return power supply to the affected parts of the networks. The availability of insufficient supply is a complex problem that requires operational experience or an automatic system. The stochastic nature of load demand significantly impacts service restoration as it results in increased restored demand in case a fault occurs during off-peak hours and helps reduce overload if the fault occurs during peak hours. The study adopts an …

Assessment Of Risk Factors Related To Body Pain Complaints In Tanzania Construction Industry, Fatma K. Mohamed

Tanzania Journal of Engineering and Technology (TJET)

The construction industry is associated with risks that can result in musculoskeletal diseases. Although young male workers who are presumed to be healthy dominate the industry in Tanzania, body pain complaints have been widely reported. The aim of this study is to assess the prevalence and causes of body pains in workers. A cross-sectional study involving 396 workers was conducted. A chi square test was used for testing association of independent categorical variables and binary logistic regression analysis was used to determine predictors for body pain complaints. The results show that all study participants complained of at least one form …

Comparison Of Meteorological Drought Indices In Tanzania Using The Meteorological Drought Monitoring Software Package, Paul Ts Limbu

Tanzania Journal of Engineering and Technology (TJET)

Low precipitation, substantial evaporation, and an unequal distribution of precipitation throughout the area are the characteristics of drought, a climatic abnormality. This study used the Meteorological Drought Monitoring (MDM) software and monthly rainfall data from the Tanzania Meteorological Authority (TMA) to examine and compare the Deciles Index (DI), Standardised Precipitation Index (SPI), Percent of Normal Index (PNI), Rainfall Anomaly Index (RAI), Z-Score Index (ZSI), China-Z Index (CZI), and Modified China-Z Index (MCZI) for drought monitoring in Tanzania from 1988 to 2017. It was found that ZSI represented the dry years better than other indices, followed by DI, RAI, PNI, SPI, …

Synthesis Of Local Control Systems For Underwater Units Cleaning Bottom Sediments In Reservoirs, Yuriy Gennadiyevich Shipulin, Zebiniso Akmalovna Zayniddinova

Chemical Technology, Control and Management

The article discusses the issues of synthesizing local control systems for underwater units for cleaning bottom sediments in reservoirs. It is shown that the protection and rational use of natural reservoirs and the fight against their premature siltation is becoming an urgent task.

It is proposed to use small-sized underwater units, consisting of information and measuring devices, to carry out search work for cleaning bottom sediments under water; control systems; actuators and means of communication with humans.

It is shown that the task of controlling the loading of an underwater unit (UU) requires maintaining optimal performance while simultaneously taking into …

Synthesis Algorithm Of Control System Based On Neural Network For The Gas And Oil Process, Jasur Sevinov, Abdishukurov Maqsudovich Shavkat, A.Z. Shodiyorov

Chemical Technology, Control and Management

Automatic control systems in the oil and gas processing are considered. After extraction of natural gas condensate, management of technological parameters plays an important role in its processing. Among the parameter of regulating algorithms, control based on neural network technology was considered. These control systems are created on the basis of algorithms of neural network technology. There are several structures of neural networks according to their structure. Differences in the process of information processing of these branching structures are considered.

Artificial Neural Network Based Grain Moisture Measuring Device, Erkin Eljaev, Shohrux Nurali O‘G‘Li Narzullayev, Elyor Faxriddinovich Khudoyberdiev

Chemical Technology, Control and Management

To date, the intellectualization of solving technical issues in managing, controlling, and measuring technological processes in all branches of industrial production is considered an urgent task. In this regard, a class of intelligent devices and sensors has emerged. Intelligent devices and sensors differ from their analog counterparts in that they have functions such as automatic adjustment of the measurement range, self-calibration, data processing, and decision-making. The article discusses the development of intelligent measuring instruments based on a capacitive transducer for measuring the moisture content of grain and grain products.

Spectrophotometric Device For Early Malaria Detection, Adrian Wasylewski, Christopher Faber, Victor Lin

Honors Thesis

Malaria remains a significant global health challenge, with millions of cases reported annually, particularly in resource-limited regions. Timely and accurate diagnosis is crucial for effective treatment and disease management. Unfortunately, there are still significant challenges in existing testing procedures, which are often expensive, inaccurate, or impractical for mass testing. While spectrophotometry has been proposed as a detection tool for other tropical diseases such as dengue fever, no prototype has been made for any disease, including malaria. This report addresses this gap by presenting a spectrophotometric-based malaria detection tool that achieves high sensitivity at a low cost. The inclusion of a …

Channel Prediction For Underwater Acoustic Communication: A Review And Performance Evaluation Of Algorithms, Haotian Liu, Lu Ma, Zhaohui Wang, Gang Qiao

Michigan Tech Publications

Underwater acoustic (UWA) channel prediction technology, as an important topic in UWA communication, has played an important role in UWA adaptive communication network and underwater target perception. Although many significant advancements have been achieved in underwater acoustic channel prediction over the years, a comprehensive summary and introduction is still lacking. As the first comprehensive overview of UWA channel prediction, this paper introduces past works and algorithm implementation methods of channel prediction from the perspective of linear, kernel-based, and deep learning approaches. Importantly, based on available at-sea experiment datasets, this paper compares the performance of current primary UWA channel prediction algorithms …

Transformer Based Deep Learning Model For Sign Language Recognition, Ganzorig Batnasan

Thesis/ Dissertation Defenses

Sign language recognition research aims to develop systems and tools that can interpret and translate sign language into text or spoken language. During the past two decades, the challenges faced in this domain are multifaceted. This thesis on sign language recognition aims to address some challenges through various approaches. The foremost challenge addressed in this thesis is reduction in accuracy that uses transformer based deep learning architecture in addition to preprocessing steps that include augmentations and transformations. The augmentations and transformation helped increase the data size. Specifically, in-house signs were generated using different persons for initial results. The video frames …

Applications, Challenges, And Research Issues For Enabling A Uav Swarm, Jennifer Hahner

Senior Honors Theses

Unmanned aerial vehicle (UAV) swarms have the potential to be useful in numerous applications due to their versatility and ability to operate without human intervention. However, this promising technology still requires further investigation, research, and testing before UAV swarms can be implemented extensively. The level of human intervention needed to control the system determines the differing levels of autonomy for UAV swarms. For swarms to become more independent, efficient algorithms for task and path planning are essential. In addition, accurate communication is essential for swarms to be able to coordinate and accomplish tasks successfully. This paper seeks to provide a …

Disturbance Observer-Based Control For Pmsg-Based Wind Turbine Considering Unbalanced Grid Conditions, Moayad Maher Alanani

Thesis/ Dissertation Defenses

A typical permanent magnet synchronous generator (PMSG)-based wind turbine system consists of an electrical generator, machine-side converter (MSC), grid-side converter (GSC), dc-link capacitor, and a passive filter such as L filter or LCL filter to connect the GSC to the host grid. When the wind turbine operates under unbalanced grid voltages, a negative sequence component is introduced to the system. This negative sequence voltage can pose challenges for classical controllers to ensure an efficient control of the PMSG-based wind turbine system. On one hand, when the control objective is to ensure injecting sinusoidal and balanced three-phase currents to the grid, …

Emerging Technologies For Automation In Environmental Sensing: Review, Shekhar Suman Borah, Aaditya Khanal, Prabha Sundaravadivel

Electrical Engineering Faculty Publications and Presentations

This article explores the impact of automation on environmental sensing, focusing on advanced technologies that revolutionize data collection analysis and monitoring. The International Union of Pure and Applied Chemistry (IUPAC) defines automation as integrating hardware and software components into modern analytical systems. Advancements in electronics, computer science, and robotics drive the evolution of automated sensing systems, overcoming traditional limitations in manual data collection. Environmental sensor networks (ESNs) address challenges in weather constraints and cost considerations, providing high-quality time-series data, although issues in interoperability, calibration, communication, and longevity persist. Unmanned Aerial Systems (UASs), particularly unmanned aerial vehicles (UAVs), play an important …

Low Impedance, Durable, Self-Adhesive Hydrogel Epidermal Electrodes For Electrophysiology Recording, Naiyan Wu

McKelvey School of Engineering Graduate Student Theses & Dissertations

Traditional electrodes used for electrophysiology recording, characterized by their hard, dry, and inanimate nature, are fundamentally mismatched with the soft, moist, and bioactive characteristics of biological tissues, leading to suboptimal skin-electrode interfaces. Hydrogel materials, mirroring the high water content and biocompatibility of biological tissues, emerge as promising candidates for epidermal electronic materials due to their adjustable physicochemical properties. However, challenges such as inadequate electrical conductivity, elevated skin impedance, unreliable adhesion in moist conditions, and performance decline from dehydration have significantly restricted the efficacy and applicability of hydrogel-based electrodes. In this thesis, we report a high-performance hydrogel epidermal electrode patch for …

Arkansas Tech University Modular Robotics Training System, Andrew L. Hilsdon, Jacob L. Crawford, Luke C. Hartman, Samuel E. Allen, Anthony W. Knudson, Kyle B. Mcmillan

ATU Scholars Symposium

Arkansas Tech University Modular Robotic Training System (ATUM RTS) project aims to combine two existing systems: The Georgia Tech Robotarium and the Micromouse maze-solving competition. The goal of ATUM RTS is to incorporate the challenge and excitement of maze-solving robots with the cloud-based learning system of the Robotarium. We intend to develop an automatic maze table with future remote capabilities to further student learning and engagement. By being able to create custom mazes with ATUM RTS, students will have access to a resource that will allow them to practically apply what they are learning in the classroom. The ATUM RTS …

Exploring Various Integration Methods Of Carbon Quantum Dots In Cspbcl3 Perovskite Solar Cells For Enhanced Power Conversion Efficiency, Eman Sawires, Zahraa Ismail, Mona Samir, Ahmed Agour, Fathy Amer, Hassan Nageh, Sameh O. Abdellatif

Electrical Engineering

No abstract provided.