Electrical and Electronics Commons^™

Compact Dual-Band Semicircular Slot Mimo Antenna Design For 5g Sub-6 Ghz Applications, Reham Wageh Abd El Salam Reham W., Amr H. Hussein Prof.Dr., Mustafa M. Abd Elnaby Prof. Dr., Hussein E. Seleem

Journal of Engineering Research

This paper presents a novel compact semi-circular slot (SCS) 4 × 4 MIMO antenna specifically designed for 5G sub-6 GHz applications, achieving significant isolation without requiring extra decoupling components. The antenna features four symmetric, orthogonally arranged elements, each sized at 42×42 .It includes a U-shaped radiating patch, which is fed by a 50-ohm microstrip line on the top surface of the substrate. A semicircle-defected ground structure (DGS) is etched on the underside to improve bandwidth and reduce overall size. To enable dual-band functionality, a T-shaped stub is incorporated into the U-shaped patch, allowing for adjustable resonant frequencies. The higher frequency …

Design And Implementation Of A Low-Cost Educa-Tional Robot For Engineering Curriculums, Diana Refaat Henry Jacob, Ashraf Mohamed Hafez, Mohamed Tarek Elawa

Journal of Engineering Research

The role of educational robots is becoming increasingly important. Many commercial educational robots differ in their abilities and price. In general, the cost of these robots presents the main cause of their limited use in the teaching process, especially in countries with limited financial resources. This work attempts to solve this problem by designing and implementing an educational robot with a limited budget. The robot was initially intended to serve higher education students' needs, especially in engineering curriculums but can be extended to other application areas. This work presents robot hardware functional blocks, mechanical struc-ture design, and 3D printing implementation. …

Assessment Of Wind Speed Characteristics And Available Wind Power Potential For Electricity Generation In Tanzania, Mwingereza John Kumwenda

Tanzania Journal of Engineering and Technology (TJET)

The energy demand and its associated crises are attracting significant attention due to population increase and economic growth especially in developing countries. Fossil fuel-based energy source stand as a prominent anthropogenic resource but they are accompanied with increased carbon emissions and heightened environmental concerns. Renewable energy sources such as wind energy can offers a lot of potential for sustainable growth in the energy sector of developing nations like Tanzania. Thus, this work investigated wind speed characteristics and available wind power potential in six selected regions in Tanzania with different topographical features for future electricity generation. The data of the wind …

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 …

Infinitesimal Elements In Cartesian, Cylindrical And Spherical Coordinate Systems, Ashanthi Maxworth Phd

EM Fields With Prof. Maxworth

In this chapter we introduce you to the infinitesimal surface and volument elements in Cartesian, Cylindrical and Spherical coordinate systems. Electromagnetic fields is based on multi-variate vector calculus. The following three documents show, how the infinitesimal surface area elements are defined in Catesian, Cylindrical and Spherical coordinate systems.

Maxwell's Second Equation: The Gauss's Law For Magnetostatic Fields, Ashanthi Maxworth Phd

EM Fields With Prof. Maxworth

Gauss's Law for magnetostatic fields says that the total magnetic flux through a closed surface is equal to zero. In otherwords, there are no magnetic monopoles. This law has been applied in multiple mathematical derivations. Watch the short video where Dr. Maxworth explains this law. In the worksheet you can observe the magnetic flux generated due to a current through a straight coaxial cable. Note that the magnetic flux always exisit as close loops making the total net flux through a closed surface zero and the direction of the magnetic field can be derived by the right hand rule, i.e …

Maxwell's Third Equation: The Faraday's Law, Ashanthi Maxworth Phd

EM Fields With Prof. Maxworth

Faraday's Law states that the voltage induced in a closed loop is equal to the rate of change of magnetic flux through that loop. As we know, when there is no fluctuating magnetic flux, there is no voltage difference across a closed loop. But when there is a changing magnetic field, a voltage is induced within a closed loop known as the electromotive force or the EMF. There are two types of electromotive forces: the motional EMF and the transformer EMF. In motional EMF the magnetic field is kept steady while the loop is moved such that it cuts the …

Characterization And Modeling Of Polyphase Machines And Power Conditioning Components, Nathan Lockhart

Electrical Engineering Dissertations - Archive

Microgrid power configurations have become increasingly prevalent in recent power systems due to the rise of power electronic energy generation, energy storage, and the many diverse electrical demands. Microgrids offer numerous advantages over traditional power electronic networks, which rely on large rotating generators to supply power over extensive distances to multiple users. Remote power grids are particularly beneficial for smaller networks that may be isolated or have unique power requirements, often incorporating energy storage to enhance operational flexibility. Advances in power electronics, such as medium voltage DC distribution, are enhancing the reliability, redundancy, and integration capabilities of isolated microgrids.

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 …

Dc To Ac Voltage Source Converter Control System, Mohummad Tark Elgassier, Jordan M. Reichhardt, Brayden Richard Young

Electrical Engineering

The Voltage Source Converter Control System integrates a control system for a 2-phase half-bridge voltage source converter (VSC) utilizing a TMS320F2837xD Dual-Core Real-Time Microcontroller. VSCs are critical for the integration of power production into the power grid. They allow for accurate control over DC-AC energy conversion. Additionally with the improvement of renewable energies VSCs play a critical role in controlling the flow of these environmentally controlled and more unpredictable sources of energy. The control system regulates the output current and voltage, regulates switching patterns, and maintains power stability under varying loads. Within the control system Digital control systems, PWM generation, …

Characterization Of Dc Arc Flash Events Generated By Electrochemical Energy Storage, Nicolaus E. Jennings

Electrical Engineering Dissertations - Archive

The increasing rise in the use of electrochemical energy storage (ECES) like in the form of valve regulated lead acid (VRLA) batteries, lithium-ion (Li-ion) batteries, electric double layer capacitors (EDLC), and metalized film, oil filled capacitors prompt new challenges concerning electric worker safety. The primary safety hazards associated with ECES are electric shock and arc flash. The electric shock hazard is well understood to the extent where it is known what potential and exposure duration will cause levels of pain and ultimately fatality. Various personal protective equipment (PPE) like insulating gloves allow electric workers to perform maintenance with sufficient protection …

Enhanced Load Detection With Data-Driven Appliance Signatures Using Mixed Integer Linear Programming In Non-Intrusive Load Monitoring, Marina Materikina

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Despite the numerous research studies and interest in the non-intrusive load monitoring (NILM) area to improve energy efficiency, the problem of accurate and precise disaggregation of electrical devices has not been solved yet. The goal of our research is to build a method with a focus on higher accuracy on complex state-based appliances, which most approaches struggle to detect due to their power signal complexity and low consumption. Our approach is NILM with data-driven signatures (DS), with the ability to potentially predict power usage over time that would work great for suitable applications such as demand response, anomaly detection, and …

Determining The Transient Electric Field And The Effect Of Pulse Repetition Frequency On The Field In A Repetitive 10-Ns Pulsed Discharge In A Quiescent Ch₄-Air Mixture, Chunqi Jiang

Bioelectrics Publications

The goal of this research is to understand the underlying physics enabled by nanosecond pulsed power in a discharge initiation and the following physicochemical processes that favor lean-fuel plasma ignition for combustion. The hypothesis of this project is that pulsed power waveforms such as the pulse repetition frequency (PRF), voltage amplitude, and dielectric surface alter the reduced electric field during the initiation of the discharge, resulting in different plasma properties, which will vary the physicochemical processes for efficient and selective radical productions. This is especially important for lean-burn combustion and reducing emission.

Enhancing Performance Of Lstm For Water Level Forecasting In Lower Mekong River With Feature Selection Strategy, Chanreng Sey Nhim

Chulalongkorn University Theses and Dissertations (Chula ETD)

This study addresses key research gaps, including the lack of systematic feature selection, structured hyperparameter optimization, and comprehensive long-term and cross-location performance evaluation in the Lower Mekong River Basin to enhance the water level forecasting performance. The research has utilized a Vanilla Long Short-Term Memory (LSTM) network trained on 22 years of historical water level data from the Mekong River Commission (MRC) and 16 localization meteorological features from Open-Meteo. The methodology uses Grid Search optimization for hyperparameter tuning and employs the Spearman rank correlation coefficient as a filter feature selection technique to identify relevant input variables and minimize redundancy. Performance …

A Study On The Impact Of Superconducting Fault Current Limiteron Arc Flash Hazard In An Industrial System, Kittipong Anantanasap

Chulalongkorn University Theses and Dissertations (Chula ETD)

The increasing integration of distributed generation raises short-circuit current levels, which lead to concerns about equipment overheating, insulation deterioration, and system stability issues. The Resistive Superconducting Fault Current Limiter (R-SCFCL) offers an effective solution by dynamically increasing circuit impedance during faults without affecting normal operation. However, its integration may alter the fault-clearing time of the protection system, which is crucial for arc-flash safety. This study evaluates the impact of R-SCFCL integration on arc-flash hazards in an industrial power system, utilizing DIgSILENT PowerFactory and calculations based on IEEE 1584. Results indicate that while the R-SCFCL effectively reduces arcing current, the incident …

Vehicle Routing Problem With Time Constraint From Multiple Origins To Selective Destinations By Using Genetic Algorithm, Manocha Kruetet

Chulalongkorn University Theses and Dissertations (Chula ETD)

This thesis addresses the vehicle routing problem with time constraints from multiple origins to selective destinations by using a genetic algorithm for efficient path planning. The focus is on optimizing field collection and repossession activities in the financial industry to enhance operational efficiency and customer satisfaction. The proposed approach integrates two main components: a tailored genetic algorithm for multi-objective optimization and a graph neural network for precise travel time estimation. The genetic algorithm is designed to minimize total travel distance or travel time and balance the workload among field collectors, while the graph neural network provides travel time estimates to …

Performance Evaluation Of Strategic Bandwidth Block Assignment For Interference Reduction In High-Density 5g Nr Cell Environments, Pasapong Wongprasert

Chulalongkorn University Theses and Dissertations (Chula ETD)

Due to the increasing demand for mobile data, mobile network operators (MNOs) typically rely on cell densification to increase capacity. However, doing so also introduces more inter-cell interference (ICI), leading to lower spectral efficiency and making further capacity enhancements challenging. This thesis explores a bandwidth block assignment method for ICI mitigation. The core idea is to divide the bandwidth of an NR carrier into two partially overlapping bandwidth parts (BWPs) to reduce the impact of ICI. By allowing the two BWPs to share the same synchronization signal block (SSB), the same attach and handover configurations can be applied. A modified …

Real-Time Monitoring System For Sedentary Behavior Using Pose-Estimation Approach, Pheng Ou Chea

Chulalongkorn University Theses and Dissertations (Chula ETD)

Long-term sedentary behavior, defined as extended periods of sitting or inactivity, increases the risk of obesity, cardiovascular disease, and other health problems. These risks are often underestimated due to low levels of physical activity. This study proposes the use of You Only Look Once (YOLO)–based pose estimation for dwell-time analysis to monitor sedentary behavior. We examined posture over an entire day to assess prolonged inactivity and encourage individuals to balance energy expenditure with available time—such as engaging in exercise in the early morning or evening according to recommended guidelines. For employees across generations, as well as for vulnerable groups such …

Bismuth Surfactant-Mediated Epitaxy Of Gaas(Bi) On On-Axis Ge(100) Substrates, Valgeir Sigmarsson

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this work, Bi-surfactant-mediated epitaxy is applied in GaAs(Bi) film deposition on nom- inally on-axis Ge(100) substrates to investigate its effect on mitigating the formation of anti-phase domains (APDs) inherent to the polar-on-non-polar GaAs/Ge(100) heterostructure. GaAs(Bi) layers were deposited by solid-source molecular beam epitaxy (MBE) with a V/III ratio of ~90 and stepwise variations in Bi flux between samples. The Bi-free GaAs sample exhibited an unstable RHEED pattern indicating ill-ordered growth mode, confirmed by AFM showing an amor- phous surface with an RMS value of ~20 nm. In contrast, Bi-assisted growth produced stable RHEED (1×3) surface reconstructions. AFM revealed single-crystal …

การจัดสรรกำลังการผลิตอย่างเหมาะที่สุดสำหรับระบบผลิตไฟฟ้าพลังงานแสงอาทิตย์ที่มีระบบกักเก็บพลังงานแบบแบตเตอรี่เพื่อการซื้อขายพลังงานแบบหนึ่งวันล่วงหน้า, กรวิชญ์ ธนบำรุงกูล

Chulalongkorn University Theses and Dissertations (Chula ETD)

ไฟฟ้าพลังงานแสงอาทิตย์มีความสำคัญมากขึ้นในตลาดการซื้อขายพลังงาน วิทยานิพนธ์นี้เสนอการจัดสรรกำลังการผลิตอย่างเหมาะที่สุดสำหรับระบบผลิตไฟฟ้าพลังงานแสงอาทิตย์ที่มีระบบกักเก็บพลังงานแบบแบตเตอรี่เพื่อให้ได้รายได้สุทธิต่อวันสูงสุดในการซื้อขายพลังงานแบบหนึ่งวันล่วงหน้า ใช้วิธีโปรแกรมเชิงเส้นแบบผสมจำนวนเต็มไบนารีในการหาค่าเหมาะที่สุด และพิจารณาปรับการทำงานของระบบ ณ เวลาจริง กับสัญญาแบบ Partial-firm ตามระเบียบคณะกรรมการกำกับกิจการพลังงาน (กกพ.) สำหรับโรงไฟฟ้าพลังงานหมุนเวียนเอกชน ใช้ข้อมูลการพยากรณ์พลังงานแสงอาทิตย์แบบหนึ่งวันล่วงหน้าในการวางแผนและใช้ข้อมูลพลังงานแสงอาทิตย์จริงในการควบคุม ณ เวลาจริง เพื่อกำหนดการอัดและคายประจุของแบตเตอรี่และการจัดสรรกำลังผลิตสำหรับระบบผลิตไฟฟ้าพลังงานแสงอาทิตย์ในการซื้อขายพลังงาน ปัจจัยสำคัญที่ส่งผลต่อขนาดของระบบกักเก็บพลังงาน เพื่อให้ผลิตไฟฟ้าได้ตามเงื่อนไขของสัญญา คือ การเรียกใช้งานความพร้อมจ่ายไฟฟ้า ส่วนการควบคุม ณ เวลาจริง วิธีที่ทำรายได้สุทธิสูงสุดคือการควบคุมเชิงทำนายแบบจำลอง (MPC) โดยการหาค่าเหมาะที่สุดในทุกขั้นเวลาอย่างต่อเนื่อง ผลการศึกษากรณีสัญญา Partial-firm ขายไฟฟ้าที่ขนาด 10 เมกะวัตต์ พบว่าขนาดที่เหมาะสมของระบบไฟฟ้าพลังงานแสงอาทิตย์คือ 18 เมกะวัตต์ และระบบกักเก็บพลังงานแบบแบตเตอรี่ที่ขนาด 35 เมกะวัตต์-ชั่วโมง