Electrical and Computer Engineering Commons^™

Enhanced Energy Harvesting From Nf-Pvdf Piezoelectric Material For Wearable Electronics: I– V Characterization And Charge-Discharge Performance, Ahmed Emara, Afaf Farag, Gehad Ali, Mohamed Mamdouh, Sameh O. Abdellatif, Khaled Nassar, Tamer Hamoud

Electrical Engineering

This study explores the utilization of fabricated piezoelectric polyvinylidene fluoride nanofiber (NF-PVDF) materials in wearable electronic sensing applications by investigating their current-voltage ( I − V ) characteristics under controlled ultra-low-frequency excitation forces. The results demonstrate a significant power harvesting capability, achieving an output power of 0.12 µW/mm2 at an operating point of 5.04 V and 7.7 µA. Additionally, the piezoelectric harvester was integrated into a charging-discharge circuit alongside a rectifier capacitor and a typical IoT wearable sensor, leveraging the advantages of a flexible substrate. Experimental measurements of the charging and discharging curves confirm the effective energy management of the …

Unified Hybrid Censoring Samples From Power Pratibha Distribution And Its Applications, Mahmoud Mansour, Hebatalla H. Mohammad Dr, Khalaf S. Sultan Prof.

Basic Science Engineering

This paper suggests an extensive inferential method for the Power Pratibha Distribution (PPD) under Unified Hybrid Censoring Schemes (UHCSs), since there is a growing interest in flexible models in both reliability and service operations. This work studies the PPD model using standard Maximum Likelihood Estimation methods and modern Bayesian approaches too. Using a complex architecture, UHCS simulates tests more closely to what is done in practice than by using more basic censoring schemes. Using analysis, the probability and statistical ranges are carefully calculated for the parameters. Tests demonstrate that Bayesian estimation gives better results than many other methods for estimation, …

Unveiling Degradation Patterns In Dye-Sensitized Solar Cells: A Machine Learning Perspective, Ahmed Alali, Mahmoud Ashraf, Ahmad Muhammad, Sameh O. Abdellatif

Electrical Engineering

This study examines the time-dependent degradation of dye-sensitized solar cells (DSSCs) by systematically investigating several critical parameters, including TiO2 thickness, porosity, dye concentration, and iodine-based electrolyte concentration. We developed a novel figure of merit (FOM) to quantify the degradation rates, utilizing a finite element model (FEM) in COMSOL to simulate performance over time. 400 DSSC samples were fabricated, resulting in a comprehensive dataset comprising over 228,000 data points derived from experimental results and simulations. The findings reveal that PCE declines significantly over time, with an average initial efficiency of 4.0% for the DSSCs, dropping to approximately 0.5% after 360 h. …

Development And Experimental Validation Of A Non-Invasive Blood Group Detection System, Nurath K. Nurudini

Tanzania Journal of Engineering and Technology (TJET)

An individual's blood group consists of red blood cell antigens whose composition is determined by protein presence, antigen structure, and gene series. Persons aged above six months have significant anti-A and/or anti-B in their serum. During transplantation and transfusion, ABO blood group identification is the most essential factor. The conventional method involves drawing blood samples from patients, and the blood group is determined based on the antigen-antibody reaction. This method consists of adding chemical reagents. However, this requires time of operation, and throughput analysis is high, and the process is also challenging to interpret. Accurate and rapid identification of blood …

Measurement Of Moisture Levels In Oils And Lubricants Using A Novel Moisture Sensor, Aaron Swartz, Ronak Ali

Electrical and Computer Engineering Graduate Research

It is very challenging to measure moisture levels in oils. There is not a good method to measure it. Using the novel moisture sensor invented by Dr. Zhi David Chen, we tried various methods to measure the moisture levels in oils. The initial trials are to immerse the sensor chip into the oils to see any sensor reading changes with the change of moisture levels in oils. It was observed that the sensor reading was unstable even after immersion into the oil for two weeks. The idea for immersion of the sensor chip into the oils failed due to the …

Design And Development Of A Half-Bridge Llc Resonant Converter Laboratory Module, Alyssa Lam

Master's Theses

Resonant DC-DC converters have become a well-known solution in power supplies due to their ability to improve efficiency by utilizing soft-switching techniques. This further has caused a growing interest in industry to use these converters for high-switching-frequency, high-efficiency, and high-power applications such as EV charging stations, photovoltaic systems, battery chargers, etc. One particular resonant topology that has gained popularity in recent years is the LLC resonant converter. Due to the prevalent use of the LLC resonant converter, it is therefore crucial for students preparing for a career path in power electronics to become well-versed in the concept and implementation of …

Piezoelectric Actuator Driver System, Daniel Hoefer

Electrical Engineering

This work presents the design, fabrication, and testing of a high-voltage piezoelectric actuator driver system purposed for integration into defense and aerospace precision motion control applications, particularly those in laser optics. The core challenge addressed was the mismatch between the standardized 28V DC power bus used in military systems and the significantly higher voltage requirements of piezoelectric actuators. Existing commercial drivers were evaluated and found unsuitable for field deployment due to inadequate ruggedness, excessive complexity, or power limitations. Consequently, a modular system architecture was designed featuring four independent driver channels, each using a high-voltage, high-current linear amplifier topology to scale …

Colloidal Quantum Dots: A Path Toward Making Mid-Wave Infrared Sensing A Ubiquitous Technology, Mohammad Mostafa Al Mahfuz

Dissertations

Reducing the size, weight, power consumption, and cost (SWaP-C) of infrared detectors could make infrared sensing more widely accessible. In the critical mid-wavelength infrared (MWIR) spectral range of 3-5 gm, commercially available detectors are limited by the high costs associated with epitaxial growth and hybridization, as well as the need for cryogenic cooling. These factors restrict their use to defense and space applications.

Colloidal quantum dots present a promising material for overcoming these challenges, with wafer-scale monolithic integration and Auger suppression being the key material capabilities to minimize the sensor's SWaP-C. Infrared sensors based on colloidal quantum dots have been …

Experimentally Driven Numerical Model Of Carbon/Polyaniline-Based Glucose Monitoring Sensors: An Evaluation Using A New Figure Of Merit, Kyrillos Selim, Ziad Khalifa, Amira Ali, Sameh O. Abdellatif

Electrical Engineering

This study presents an experimentally driven numerical model for evaluating carbon/polyaniline (PANI)-based glucose monitoring sensors (GMSs), focusing on innovative configurations using graphene-PANI and carbon nanotube (CNT)-PANI composites. We performed a thorough analysis of the morphological, electrophysical, and electrical properties of these materials, ultimately leading to the extraction of key electrical parameters for integration into a finite element model (FEM). This model simulates the entire sensor, enabling the estimation of critical performance metrics such as sensitivity, limit of detection (LOD), linearity, and power consumption. Our findings demonstrate that the CNT-PANI configuration significantly outperforms the laser-induced graphene (LIG)-PANI electrode, achieving a figure …

Machine Learning-Driven Optimization Of Piezoelectric Energy Harvesters For Low-Frequency Applications, Kyrillos Selim, Login Moustafa, Sameh O. Abdellatif

Electrical Engineering

To enhance energy harvesting efficiency, this paper explores the optimization of a cantilever-based piezoelectric energy harvester by integrating advanced machine learning (ML) methodologies. Leveraging a meticulously trained model on data sourced from a sophisticated two-dimension (2D) COMSOL Multiphysics numerical simulation, the study focuses on the critical input parameters, particularly the dimensions of the piezoelectric thin film. Through extensive simulations, the analysis delves into power density extraction and resonance frequency for various configurations. The culmination of rigorous simulations and analysis has led to the identification of an optimal design configuration for the cantilever piezoelectric energy harvester, characterized by a length of …

Functional Devices Based On Freestanding 2d Materials, Shijue Xu

McKelvey School of Engineering Graduate Student Theses & Dissertations

Two-dimensional (2D) materials have attracted extensive attention in the field of nanoelectronics due to their atomic-scale thickness, high surface-to-volume ratio, tunable electronic properties, and compatibility with low-temperature processing. These characteristics make them highly suitable for the construction of emerging device architectures, particularly in both ionic and electronic devices.

In this work, we investigate the application of 2D materials in two distinct classes of devices: ionically-driven memristors and electronically-dominated metal–semiconductor contacts. For the memristor study, we fabricate heterostructure-based resistive switching devices using h-BN and WSe₂ as active layers. These 2D material-based memristors exhibit stable power consumption loops and high linearity …

Automation Programming For Uhv-Cvd Growth Of Group Iv Materials, William Hay

Electrical Engineering and Computer Science Undergraduate Honors Theses

The automation programming of a UHV-CVD reactor for group IV materials was performed. The reactor was programmed to perform all the necessary functions for a Germanium (Ge) growth with little response from the user. The overall goal was to fix an Argon purge program to clean out the process chamber of gases and create an Excel output program to ease any work on the user. There were also general fixes and address name changes that occurred throughout the program. Then, a one step and two step growth of a Ge material was formed in a UHV-CVD reaction for analysis. Germanium …

Defect Characterization Of Sic Schottky Barrier Diode Using Deep Level Transient Spectroscopy, Zachary I. Mccoy

Electrical Engineering and Computer Science Undergraduate Honors Theses

The aim of this project is to use deep level transient spectroscopy (DLTS) to energetically evaluate defects by using the carrier concentration dependence on temperature and where these carriers may experience deviation from standard predictions. These defects become apparent through multiple C-V measurements that are swept through a temperature range. By analyzing trends with respect to temperature, the defects can be energetically “located,” and thus identified. This identification can help streamline semiconductor material manufacturing/growth because DLTS identifies potential defect causes by providing data to characterize semiconductor mid-band defects. DLTS can assess nearly all parameters associated with traps/defects including density, thermal …

Investigation And Characterization Of Silicon Carbide Power Mosfets, Vincent Hassman

Electrical Engineering and Computer Science Undergraduate Honors Theses

As engineers constantly seek to make solar power systems smaller, cheaper, and more efficient, technological enhancements in the electronics that run them are required. One of the most fundamental electronic components of any solar system is the inverter, which takes DC current from the solar cell and turns it into AC current that is supported by the grid. This is done with metal oxide semiconductor field effect transistors (MOSFETs). Through more advanced MOSFET technology, inverters can switch at a higher frequency, increasing efficiency and reducing size and cost.

MOSFET performance can be enhanced by swapping the traditional silicon substrate with …

Spin Coater Design With Pid Algorithm Using Polynomial Regression Approach And Bias Tuning For Tio2 Deposition Process, Geo Surya Andika, Nofrijon Sofyan, Donanta Dhaneswara, Akhmad Herman Yuwono

Journal of Materials Exploration and Findings

The thin-film deposition technique using spin coating offers a cost-effective alternative to Chemical Vapor Deposition (CVD) and Physical Vapor Deposition (PVD). The spin-coating process requires precise control of the motor drive system to ensure that the rotational speed, measured in rotations per minute (RPM), aligns with the set point and remains stable. This study presents the design and development of a spin coater prototype to achieve uniform thin-film deposition. The control method employed utilizes a Proportional-Integral-Derivative (PID) algorithm, incorporating a polynomial approach with bias tuning. The PID control was chosen to achieve stable operation in a non-linear system. The performance …

Investigation Of The Electrical Capacitance Tomography System For Determining The Spatial Distribution Of Moisture In Grain Storage, Shamte J. Kawambwa

Tanzania Journal of Engineering and Technology (TJET)

Excessive moisture content (MC) in stored grains promotes the growth of fungi and molds, which affects the quality of the grains. Effective grain monitoring methods are essential for detecting and managing grain spoilage. Electromagnetic imaging (EMI) techniques provide a promising alternative to traditional techniques by visualizing the spatial distribution of moisture within grains rather than merely average MC values offered by traditional techniques. However, existing EMI approaches often use hard-field waves, which are expensive and fragile. This study introduces an Electrical Capacitance Tomography (ECT) system that employs soft-field waves to monitor the moisture content of the grains. The system was …

Influence Of Substrate Temperature On The Properties Of Reactive Dc Magnetron Co-Sputtered Ag-Doped Tio2 Thin Films, Hezekiah B. Sawa

Tanzania Journal of Engineering and Technology (TJET)

This study reports on the influence of substrate temperature on the properties of Ag-doped TiO2 thin films. The films were deposited by reactive DC co-sputtering of Ti and Ag targets at different substrate temperatures and Ag target sputtering powers. Grazing incident X-ray diffractometer confirmed that all films were polycrystalline with dominant peak oriented along (101) planes representing the anatase TiO2 phase. The average grain size of the samples improved with increase in deposition temperature. At a substrate temperature of 450 ℃, the samples had a dominant peak representing the rutile phase, suggesting partial transformation from anatase to rutile phase. The …

Design And Performance Analysis Of Fiber Bragg Grating Temperature Sensor For Industrial Processes Sensing Applications, Paul Stone Stone Brown Macheso S.B.

Tanzania Journal of Engineering and Technology (TJET)

The Fiber Bragg Grating (FBG) sensor has become a widespread sensing device because of its small size, passive design, immunity to electromagnetic interference, and direct ability to measure physical properties like temperature and strain. Recently, femtosecond infrared laser processing and regeneration techniques have resulted in the development of stable high-temperature gratings, which are a powerful tool in smart factories, an aspect of the fourth Industrial Revolution (4IR), and show promise for application in harsh environments like high pressure, high temperature, or ionizing radiation. The development of stable high-temperature gratings that can withstand harsh environmental factors like high temperatures, pressures, and …

The Role Of Counter Electrode In Perovskite Solar Cell On Silicon Substrate To Enhance Power Conversion Efficiency For Cmos-Compatible Applications, Sameh O. Abdellatif, Eman Sawires

Electrical Engineering

This study investigates the impact of various counter-electrode materials on the overall power conversion efficiency (PCE) of perovskite solar cells (PSCs) fabricated on silicon substrates. We examined four distinct configurations using fluorine-doped tin oxide (FTO) as bare cell, copper (Cu), aluminum (Al), and highly p-doped silicon wafers as counter electrodes. The results indicate that the PSCs with Cu achieved the highest short-circuit current density (JSC) of 17.11 mA/cm2, while the p-doped silicon and aluminum showed lower JSC values of 16.19 mA/cm2 and 16.51 mA/cm2, respectively. Open-circuit voltage (VOC) values remained competitive across all cells, with FTO achieving a VOC of …

A 0.18 Μm Cmos 40 Ghz Miniaturized Coupled-Line Coupler With Enhanced Directivity, Elsayed Ibrahim Elsaidy, Amr H. Hussein Prof.Dr., Mustafa M. Abd Elnaby Prof. Dr., Anwer S. Abd El-Hameed Dr.

Journal of Engineering Research

No abstract provided.

Introducing A Novel Figure Of Merit For Evaluating Stability Of Perovskite Solar Cells: Utilizing Long Short-Term Memory Neural Networks, Zahraa Ismail, Ahmed Alali, Mahmoud Ashraf, Ahmad Muhammad, Sameh O. Abdellatif

Electrical Engineering

This study introduces a novel figure of merit for evaluating the stability of perovskite solar cells (PSCs) by employing advanced Long Short-Term Memory (LSTM) neural networks to investigate degradation mechanisms. By harnessing the power of artificial intelligence and data analytics, we analyzed extensive datasets encompassing PSC parameters, experimental results, and environmental conditions, revealing critical insights into the degradation patterns affecting cell performance over time. Our findings indicate that the LSTM model effectively captures and predicts the complex relationships between key design parameters—efficiency, fill factor, and open-circuit voltage—and degradation-induced changes in PSCs. Specifically, we identified three degradation coefficients associated with the …

Gratings For Enhanced Sensitivity: Advancing D-Shaped Optical Fiber Surface Plasmon Resonance Sensors With Ag-Fe2o3 Structures, Yomna Seliem, Sameh O. Abdellatif

Electrical Engineering

This research delves into enhancing biosensing sensitivity by optimizing D-shaped optical fiber surface plasmon resonance (SPR) sensors employing - structures. By investigating the influence of different grating structures—rectangular, triangular, and elliptical—on sensor performance, a comprehensive analysis was conducted to ascertain the impact of these structural variations on sensitivity and detection precision. The study revealed that while the rectangular structure exhibited a sensitivity of 6.4 µm/RIU, the triangular structure outperformed with an impressive sensitivity of 7.2 µm/RIU. Moreover, the detection accuracy, quantified by the detection angle (DA), reached µ for the triangular grating, surpassing the rectangular grating’s detection angle of µ. …

Integration Of Artificial Intelligence With A Customized Four-Probe Station For I-V Characteristic Classification And Prediction, Sameh O. Abdellatif, Ahmed Ghanem, Ahmmat Abdel Whahid, Amr Hatem, Belal Ahmed

Electrical Engineering

The incorporation of Artificial Intelligence (AI) is pivotal in automating intricate technical tasks, significantly enhancing accuracy and efficiency while alleviating the burdens of repetitive monitoring traditionally borne by technicians. This study focuses on developing a customized four-probe station integrated with sophisticated AI models aimed at classifying current–voltage () characteristics and extracting essential parameters. Our methodology encompasses the fabrication of precision-engineered gold-plated probes, meticulously assembled with a three-dimensional (3D) moving head to ensure optimal contact and measurement fidelity across a variety of electronic and optoelectronic devices. Data acquisition is executed via a source meter unit, followed by rigorous post-processing utilizing advanced …

Efficient Operation Of Direct Coupled Solar Home Pv System: A Case Of Solar Home Pv System Installed In Dodoma, Tanzania, Sarah P. Ayeng'o

Tanzania Journal of Engineering and Technology (TJET)

Direct coupled Photovoltaic (PV) system is a common topology among most of the off-grid communities in the world. This topology has less components hence resulting in low investment costs. However, it suffers much losses when battery operating voltage is far from maximum power point voltage of PV modules. This scenario can be attributed by different factors such as; variation in solar radiation, load profile and temperature. Efficient operation of these systems is required in order to reduce losses. Usually in direct coupled system, PV modules are connected in parallel with batteries through a charge controller hence making PV output to …

Photonic Crystal Devices For Chip Scale Sensing Systems, Yudong Chen

Electrical Engineering Dissertations - Archive

This thesis investigates the design and integration of photonic crystal (PC) structures for compact, high-performance optical platforms, with a focus on applications in gas sensing, on-chip lasers, and flat optics. Chapter 1 introduces the fundamental principles of PC design and simulation, highlighting their potential to replace bulky components in micro-gas chromatography (µGC) systems through miniaturization and integration. Chapter 2 explores PC-based nanobeam lasers, including the Lambda-Scale Embedded Active-Region Photonic Crystal (LEAP) laser, which demonstrates strong optical confinement and energy-efficient operation, with energy consumption as low as 8 fJ/bit. These laser designs are evaluated for their suitability in low-power, high-speed on-chip …

Epitaxial Quantum Dot Scintillators With Monolithic Photodetector Integration: Physics, Fabrication And Characterization Of Materials And Devices, Allan Oreave Minns

Electronic Theses & Dissertations (2024 - present)

This dissertation discloses the physics, fabrication, and characterization of high-performance scintillator detectors based on epitaxial InAs quantum dots (QDs) in GaAs. The detector crystals grown include monolithically integrated In_0.35GaAs photodetectors with Al_0.92-0.6In_0.03-0.35Ga_0.05As metamorphic buffer layers (MBL). A device fabrication process was developed for the lithographic patterning, chemical etching, contact metallization and readout integration of materials grown by means of molecular beam epitaxy (MBE) on 3-inch GaAs (001) wafers. Low capacitance integration with readout electronics was achieved through wire bonds to custom printed circuit boards (PCBs) with commercial components.

The relationship between device …

The Impact Of Chromium Ion Implantation On Ald Lead Chalcogenide Thin Films, Haifeng Cong, Charlotte Poterie, Jean Francois Barbot, Helmut Baumgart

Electrical & Computer Engineering Faculty Publications

Inherently the synthesis of semiconducting materials by Atomic Layer Deposition ALD produces only intrinsic undoped films which require the introduction of small amounts of impurities for doping to change them into extrinsic semiconductors. Apart from various in-situ diffusion doping techniques like delta doping during the ALD process, post deposition doping by ion implantation affords the best control of dose and doping profile. The present study investigates the impact of 180 keV Cr⁺ ion implantation on the properties of semiconducting ALD lead chalcogenide thin films to improve their thermoelectric figure of merit. The implantation was accomplished with 180 keV Chromium …

Stack Bonding In Pentacene And Its Derivatives, Craig A. Bayse

Chemistry & Biochemistry Faculty Publications

Understanding the nature of π-stacking interactions is important to molecular recognition, self-assembly, and organic semiconductors. The stack bonding order (SBO) model of π-stacking has shown that the conformations of dimers occur when the combinations of monomer MOs are overall stack bonding in character. DFT calculations show that minima found on the potential energy surface for the π-stacked dimers of pentacene and perfluoropentacene occur when the dimer MOs are constructed from combinations of monomer MOs with an allowed SBO. An ex-amination of the MOs of π-stacked dimers extracted from X-ray structures of alkynyl derivatives like TIPS-pentacene pack at one or more …

Surface Morphology And Moisture Adsorption/Desorption Characteristics Of Hybrid-Dielectric Moisture Sensors, Ronak Ali

Theses and Dissertations--Electrical and Computer Engineering

Relative humidity sensors are used for high-humidity measurement. Moisture sensors, or dew point sensors are used for low-humidity measurement (< 1 ppm_v). The dissertation contains two parts of studies. In the first part, the effect of surface morphology on the response speed of moisture sensors is studied. Moisture sensors using α-Al₂O₃ films as porous dielectric materials deposited by anodic spark deposition are studied. In this part of the study, a variety of small pores have been studied to investigate the response speed of moisture sensors. Three different surface morphologies have been studied using scanning electron microscopy. One …

Lifecycle Carbon Footprint And Sustainability Evaluation Of Dram-Based Processing In Memory Computing Architectures, Samrat Pravin Patel

Theses and Dissertations--Electrical and Computer Engineering

The use of computing technologies has significantly enhanced several aspects of our day-to-day lives. But it has still revealed significant environmental concerns, primarily related to greenhouse gas emissions and energy consumption. Initially, the primary environmental problems associated with computing were energy consumption during device operation. However, with the rapid advancement of technology and increasing computational demands, attention has shifted towards the embodied carbon footprint. This term refers to the total greenhouse gas emissions throughout a product’s lifecycle from the extraction of raw materials to end-of-life processing. It has become increasingly significant in the context of manufacturing integrated circuits (ICs), such …