Browsing by Author "Saeed, Ahmed"

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Bandwidth Broadening of Piezoelectric Energy Harvesters Using Arrays of a Proposed Piezoelectric Cantilever Structure
(MDPI AG, 8/17/2021) Salem, Marwa S; Ahmed, Shimaa; Shaker, Ahmed; Alshammari, Mohammad T; Al-Dhlan, Kawther A; Alanazi, Adwan; Saeed, Ahmed; Abouelatta, Mohamed
One of the most important challenges in the design of the piezoelectric energy harvester is its narrow bandwidth. Most of the input vibration sources are exposed to frequency variation during their operation. The piezoelectric energy harvester’s narrow bandwidth makes it difficult for the harvester to track the variations of the input vibration source frequency. Thus, the harvester’s output power and overall performance is expected to decline from the designed value. This current study aims to solve the problem of the piezoelectric energy harvester’s narrow bandwidth. The main objective is to achieve bandwidth broadening which is carried out by segmenting the piezoelectric material of the energy harvester into n segments; where n could be more than one. Three arrays with two, four, and six beams are shaped with two piezoelectric segments. The effect of changing the length of the piezoelectric material segment on the resonant frequency, output power, and bandwidth, as well as the frequency response is investigated. The proposed piezoelectric energy harvesters were implemented utilizing a finite element method (FEM) simulation in a MATLAB environment. The results show that increasing the number of array beams increases the output power and bandwidth. For the three-beam arrays, at n equals 2, 6 mW output power and a 9 Hz bandwidth were obtained. Moreover, the bandwidth of such arrays covered around 5% deviation from its resonant frequency. All structures were designed to operate as a steel wheel safety sensor which could be used in train tracks. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Full Optoelectronic Simulation of Lead-Free Perovskite/Organic Tandem Solar Cells
(MDPI AG, 2023-02) Salem, Marwa S; Shaker, Ahmed; Abouelatta, Mohamed; Saeed, Ahmed
Organic and perovskite semiconductor materials are considered an interesting combination thanks to their similar processing technologies and band gap tunability. Here, we present the design and analysis of perovskite/organic tandem solar cells (TSCs) by using a full optoelectronic simulator (SETFOS). A wide band gap lead-free ASnI2Br perovskite top subcell is utilized in conjunction with a narrow band gap DPPEZnP-TBO:PC61BM heterojunction organic bottom subcell to form the tandem configuration. The top and bottom cells were designed according to previous experimental work keeping the same materials and physical parameters. The calibration of the two cells regarding simulation and experimental data shows very good agreement, implying the validation of the simulation process. Accordingly, the two cells are combined to develop a 2T tandem cell. Further, upon optimizing the thickness of the front and rear subcells, a current matching condition is satisfied for which the proposed perovskite/organic TSC achieves an efficiency of 13.32%, Jsc of 13.74 mA/cm2 , and Voc of 1.486 V. On the other hand, when optimizing the tandem by utilizing full optoelectronic simulation, the tandem shows a higher efficiency of about 14%, although it achieves a decreased Jsc of 12.27 mA/cm2 . The study shows that the efficiency can be further improved when concurrently optimizing the various tandem layers by global optimization routines. Furthermore, the impact of defects is demonstrated to highlight other possible routes to improve efficiency. The current simulation study can provide a physical understanding and potential directions for further efficiency improvement for lead-free perovskite/organic TSC.
Harmonizing power systems with a 13-level modified Packed U-Cells multi-level inverter: Design and implementation
(Elsevier B.V, 2024-04) Fouda, Sherouk; Salem, Marwa S; Saeed, Ahmed; Shaker, Ahmed; Abouelatta, M; Abou El-Ela, M
Traditional multilevel inverter designs often face complexity challenges, prompting the need for a simplified solution. This study introduces and evaluates the performance of a Modified Packed U-Cells (MPUC) inverter in the realm of multilevel inverter technology. The study addresses challenges associated with conventional multilevel inverters and proposes the MPUC inverter as a solution to simplify the design complexity. The MPUC inverter, utilizing three DC sources and eight switches, presents a groundbreaking thirteen-level output waveform. The primary focus lies in assessing the inverter's performance in terms of Total Harmonic Distortion (THD) and output voltage. Utilizing MATLAB/Simulink, the inverter's performance is evaluated with and without Pulse Width Modulation (PWM) strategies. The results reveal a notable reduction in THD, from 26.25% to 9.91% post-filtering when PWM is not employed. Various multi-carrier Level-Shifted PWM strategies, including PDPWM, PODPWM, APODPWM, and COPWM, are explored to enhance output waveform smoothness and efficiency. Unequal Carrier strategies, specifically UEAPDPWM and UEAPODPWM, emerge as superior in THD management at different frequency ranges. The study further incorporates real-time hardware implementation of the proposed 13-level MPUC topology, highlighting the success of the UEAPD-PWM strategy in improving waveform quality. The research aims to establish a multilevel inverter design protocol meeting international standards and emphasizes the pivotal role of PWM techniques in enhancing waveform quality. This comprehensive evaluation contributes to advancing the field of multilevel inverter technology and sets a benchmark for future research in this domain.
A High-Performance Self-clocked Digital-Output Quartz Gyroscope
(IEEE, 2015) Ismail, Ayman; Ashraf, Khaled; Metawe, Ahmed; Mostfa, Islam; Saeed, Ahmed; Helal, Eslam; Essawy, Mostafa; Abdelazim, Mohamed; Ibrahim, Mostafa; Raafat, Ramy; Abdelbary, Eslam; Alaa, Islam; Nabil, Marawan; Mansour, Abdelrahman; Ibrahim, Bassem; Elsayed, Ayman
High-performance electro-static gyroscopes require expensive vacuum-packaging, to maintain the high-Q of the MEMS, and may require high actuation voltages. Piezo sensors, on the other hand, do not suffer from these shortcomings. In this work, the architecture and the measurements results of a high-performance quartz gyro are presented. The architecture of the gyroscope interface ASIC adopts a mostly-digital implementation, where the drive-loop processing, demodulation, and post-filtering are implemented in the digital domain. Furthermore, the ASIC clock is based on self-clocking scheme, where the gyro drive frequency drives all internal clocks. The digital implementation, combined with self-clocking, allows the read-out ASIC to interface to different quartz-gyro sensing elements, with a wide range of drivefrequencies. The ASIC is tested with a tuning fork quartz gyro sensing element. The complete gyro sensor module achieves a ±500 deg/s input range, and a noise-floor of 2.5 mdeg/s/√Hz.
Logical Design for an Agriculture System
(MSA, 2022) Saeed, Ahmed; Maged, Marina; Shaker, Marwa
A system to provide modern precision agriculture to maximize the benefits and gains of the enhanced Algorithms in the agriculture sector, especially on the productivity of the crops to the firms that in the food production using the modern methods in planting, monitoring, and controlling the crops. Using algorithms for environmental sustainability could aid our recent attempts to protect the environment. The system aims to minimize a lot of problems in agriculture which help in growing crops in a controlled environment. This system will use internet of things (IoT) technology, and algorithms, to automatically detect the crop in detail. First, water First, water resources management could be improved and obtain a maximum result by utilizing the internet of things (IoT) using the sensors to calculate the exact amount needed. Moreover, Disease and weed management, crop health monitoring with algorithm has a great impact on crop health monitoring, unmanned aerial vehicle (UAVs) with high-tech cameras that capture photos of the crops, bots that scan any harmful weed on the surface all of that will be transferred through wireless sensor network will help in detecting the diseases and weed to be eliminated. Implementing a wireless sensor network is essential for the IoT of precision farming to work, it is basically a collection of sensors and cameras deployed to it, coordinates the data collected at the central location that will be on the cloud, then the recorded data will be analysed using the Algorithms then give the results that should help taking better decisions for the huge lands. Finally, the combination of the elements of precision farming allows continuous monitoring of the land and will give the user a chance for better management of the land with low cost, power saving, fewer workers, and fewer errors.