Polymer Electrolyte Membrane Fuel Cells (PEMFCs) are a promising technology for clean and efficient energy production. PEMFC was initially developed for the space programs in the 1960s, but today, it finds its application in numerous engineering applications. Growing concerns about fossil fuel depletion and global warming, along with recent advances in renewable energy and the hydrogen economy, have further supported its development. This comprehensive review consolidates modeling approaches, performance analyses, thermal management strategies, and future prospects of PEMFC technology. The analysis of the characteristics of Voltage-Current (V-I) and subsequent examination of the fuel cell’s efficiency include the evaluation of thermal and other input parameters. For instance, adopting the optimum thickness of catalyst layers of the anode (0.0231 mm) and cathode (0.0315 mm) current collectors enhances the performance of PEMFC by 6.8%. Experimental results show PEMFC performance peaks at 65°C, with lower temperatures reducing power. Optimal humidity improves performance, but excess causes flooding. Active water cooling enhances thermal management, boosting power density and stability compared to passive cooling. It is also noticed that altering the temperature and input values of the fuel cell results in variations in voltage losses. Compilation of the scattered work and providing the readers with an inventory to comprehend about the gaps in this particular research area for future work advocates the novelty of this review paper.

Fault-tolerant control (FTC) techniques have the potential to significantly enhance the dependability of voltage source inverters (VSI) and are becoming popular. This study presents an innovative fault tolerance approach for designing a very dependable induction motor drive (IMD) that incorporates both analytical (active) and hardware redundancies. The created model aims to enhance fault tolerance against the current sensor, speed sensor, and IGBT switch failures in the inverter module. The Active Fault Tolerant Control System (AFTCS) has been applied to the speed sensor to detect any faults in the sensor. If a fault is detected, the system will replace the defective value with an estimated value for open loop speed estimation. This estimation is based on a flux estimation observer. The fault tolerance of the current sensors is designed such that to replace the defective value with the average value of the other two functional current sensors in the event of a failure in one sensor assuming that only one sensor gets faulty at a time. The Fault Detection and Isolation (FDI) unit is designed to rapidly identify and replace a defective switch with a backup redundant switch in the shortest possible timeframe. The stability and convergence of the observer is also proved using the Lyapunov theorem. The use of Markov chains in the reliability investigation further substantiated the system's exceptional dependability. To evaluate the effectiveness of the suggested approach, a variable-speed induction motor with a power capacity of 1.1kW is constructed using MATLAB/Simulink. A 3-phase inverter and fault detector unit are implemented on an STM32-Nucleo-F103RB board with hardware-in-the-loop capability to validate the accuracy of the simulation results to highlight the robustness of the developed active fault-tolerant control. The simulation results coupled with the hardware-in-the-loop experiment demonstrate that the IM drive maintains its stability with little performance degradation in the events of faults in the speed and current sensors as well as inverter switches. Finally, a comparison with the existing literature was carried out to showcase the improved performance and heightened dependability of the proposed model.

The fabrication of hollow fibre membrane modules is affected by many spinning variables, including polymer composition, bath temperature, bore fluid ratio, fibre take-up velocity, and air gap length, resulting in varying properties. This study uses a dry-jet wet-spinning process to investigate the morphology and characteristics of PVDF hollow fibre membranes prepared at 10 cm (P10) and 20 cm (P20) air gap lengths. Polypropylene glycol was used as an additive. The dope extrusion rate, coagulation bath temperature, bore fluid ratio, and take-up velocity were set at 4 rpm, 30°C, 1.5 ml/hr, and 2 m/min, respectively. Atomic force microscopy determined the pore size distribution, roughness, and membrane thickness. Field emission scanning electron microscope (FESEM) analyzed membrane morphology. Membrane performance was tested using 10 mg/L of synthetic protein solution. The results showed that the diameters of the fibers as well as the inner and outer lumens were significantly influenced by the air gap. Membrane dimensions decreased with the increased air gap distance with the outer and inner diameter by 5% at a 10 cm air gap. FESEM images verified that the thickness of the skin layer increases with the increase in air gap distance. The resulting roughness of the membrane layer was found to be dependent on the pore size of the support layer. The protein separation test achieved the best rejection of 98 % using the P20 membrane. Thus, selecting an optimum air gap distance for hollow fibre membrane fabrication was discovered to be a viable strategy for improving separation performance in membrane filtration and improving solute separation in wastewater.

By Haider M. Al-Juboori, Mohammed Z. Al-Faiz & 1 more. The final consequences of Gaussian electron beam in free electron laser amplifier is found by solving integro-differential equation using symbolic toolbox services in MATLAB

An empirical model is developed to precisely identify the new crescent visibility of each Hijri month. The model is based on the actual real measurements of the moon motion. The model used the sinusoidal behaviour to model the relative motion of the lunar with respect to the earth. The model stability is achieved by the exact matching between the sine wave and the phases of the moon crescent, with respect to an observer from the earth. The accuracy of the model is granted by using the most accurate measurements for the motion of the moon. The model is applied to 18 Hijri months, from Shaban 1443 H to Muharam 1445 H. The moon sighting of these 18 months are obtained and compared with three references, the Um-Alqura calendar, Al-Tawqifat Alelhamih book and the moon visibility curves. The comparisons are discussed and concluded the reliability of the present model.

This article introduces the layout of a traditional (PI) Proportional Integral controller via (FA) Firefly Approach to adjust the speed of the commonly used motor; (IM) Induction Motor; supplied by (WT) Wind Turbine as a one of renewable energy resources. WT acts as a main mover to a joined (DC) Direct Current source. DC/AC inverter is utilized to obtain a 3 phase system from the product of DC generator. The developed layout process of the speed controller is formed as a time domain optimization task. FA is involved to seek optimum elements of the controller by reducing the suggested objective time function. The attitude of the decided FA has been valued with the attitude of the traditional (ZN) Zeigler Nichols and (PSO) Particle Swarm Optimization to confirm the supreme adequacy of the developed FA in setting the PI controller. Moreover, the attitude of the suggested controller has been valued for the variation of load torque and speed WT. Imitation results prove the better achievement of the tuned PI elements relied on FA compared with tuned PI elements based on PSO and traditional one along a vast scope of working cases.

The present study is concerned with evaluating the pin-on-disk test rig usage and the measurements conducted to recognize the occurrence of the stick-slip phenomenon. The test rig consists of two separate blocks to ensure that the vibration of the elastic disk and emitted noise are completely adverted to friction between the moving pin and stationary steel disk. The occurrence of stick slip is clearly picked up using near field noise measurements. It can be distinguished from the vibration signal as high consecutive spikes, but the existence of such spikes is clearer and more definite in the noise signature.

This study uses GIS spatial analysis and open-source data based on flood hazards formulas to provide a thorough analysis and forecast of floods using Geographic Information Systems (GIS) and Remote Sensing (RS). The Wadi Baysh Dam overflowed with water in 2016 as a result of the torrential downpour that hit the dam, its streams, and the surrounding surroundings results the increasing the storage capacity. In terms of water reserves, it is the dam that is thought to be the biggest in the Kingdom. Some settlements in Baysh, which are under siege since their highways are blocked off, suffered greatly as a result of flooding. However the storage capacity of Wadi Baysh Dam around 200 million cubic meters of water. In order to identify the actual Wadi Baysh flood-vulnerable area, this study combined data from remote sensing, the Geographic Information System (GIS) technique, and an Analytical Hierarchy Process (AHP) computation. The investigation was carried out to determine the viability of using remote sensing open-source data,basemap of the study area andArcGIS10.4 software in Wadi Baysh risk management. Slope (10%), height (15%), drainage density (20%), distance to stream (20%), rainfall intensity (25%), and land cover (10%) all have a proportion of relative weight that determines how flooding is analyzed. As a result of the most recent GIS analysis (weighted overlay approach), five zones are identified within the extracted flood region based on the categories of hazard. There are ten blocks in all—five in a high-risk area and five in a moderately dangerous one. The paper looks at the flood risk in Wadi Baysh using a combination and integration betweenremote sensing opensources data and GIS models. High precipitation and runoff in the dam’s downstream sections will be the main cause of difficulties, causing a great deal of death and destruction to agricultural and urban areas. Eventually, a control room connected to the GIS model and remote sensing devices will be needed in this valley to implement an efficient warning system and flood hazard management system.