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Go to Editorial ManagerThe mixture (CdS-CdSe) thin films were fabricated by the thermal evaporation technique under very low pressures with a deposition rate (R) of 0.2 nm/sec and a 400 nm thickness (TH). The photoelectric and thermal properties of these films have been studied at different base layer temperatures. It was found that there is a linear relationship between the base layer (substrate) temperature and photocurrent of these photosensitive films. There has been a very influential parameter on the samples, which is the substrate temperature (Ts), where the optimum Ts was (170 °C) with a high adhesion coefficient. The sample that was deposited at this Ts, has good properties compared to other samples. Also, there is a direct relationship between the surface current and the operating temperature for fabricated films. X-ray diffraction (XRD) tests were taken for fabricated films which have been identified as polycrystalline with hexagonal and cubic-phase structures with different directional roles. The dominant direction of CdS 002 and 111 for CdSe. Analysis for films that were fabricated at (210 oC) and (90oC) shows an excess of (S) and (Cd) respectively. This condition greatly affects the film resistivity. In future work, new and different results can be obtained using different preparation parameters.
Inductors play a major role in the power electronics domain, particularly in DC-DC converter design. The objective of this paper is to reach inductance value by means of fewer turns, using Litz wire wound on a ferrite core. In the manufacture of inductors, the key aspects of the design criteria include the choice of the core material, the type of copper coil and insulation materials, and their overall size. Taking into consideration the design parameters with no compromises on performance, Litz wire with the least turns is introduced into an inductor in certain DC-DC converters. Once the DC settled voltage is reached, it is given to a single-phase inverter for loading and application measures. This approach provides a small-level inductor design for maximized efficiency with improved thermal behavior. The hardware model for the proposed method has been developed using a DC-DC converter fed with a single-phase inverter model. The proposed DC-DC converter has been tested, performance-wise, by applying different load levels. It is observed, from the results, that the Litz wire-based approach achieves maximum efficiency with improved thermal behavior.
The electrical and radio frequency (RF) characteristics of InAlGaN/GaN high electron mobility transistors (HEMTs) device with cap layer are presented in this work. In this work, Silicon carbide was used as a substrate for its excellent thermal conductivity. Here, the thermal model was used to investigate the simulation of temperature distribution at 300k. Moreover, the DC and AC performance characteristics of the device were investigated using Silvaco Atlas Technology Computer Aided Design TCAD simulator. The results showed that, the maximum obtained drain current that was 1.35 A. In addition to, the RF parameters were extracted. The cut-off frequency ft is (73 GHz), the maximum oscillation frequency fmax is (353 GHz), maximum stable gain (Gms) and maximum available gain (Gma) with a value of about (116 dB). The obtained results showed that the InAlGaN/GaN HEMT device based on SiC performance is suitable for microwave applications.
Due to the changing flow conditions during the pipeline's operation, several locations of erosion, damage, and failure occur. Leak prevention and early leak detection techniques are the best pipeline risk mitigation measures. To reduce detection time, pipeline models that can simulate these breaches are essential. In this study, numerical modeling using COMSOL Multiphysics is suggested for different fluid types, velocities, pressure distributions, and temperature distributions. The system consists of 12 meters of 8-inch pipe. A movable ball with a diameter of 5 inches is placed within. The findings show that dead zones happen more often in oil than in gas. Pipe insulation is facilitated by the gas phase's thermal inefficiency (thermal conductivity). The fluid mixing is improved by 2.5 m/s when the temperature is the lowest. More than water and gas, oil viscosity and dead zones lower maximum pressure. Pressure decreases with maximum velocity and vice versa. The acquired oil data set is utilized to calibrate the Support Vector Machine and Decision Tree techniques using MATLAB R2021a, ensuring the precision of the measurement. The classification result reveals that the Support Vector Machine (SVM) and Decision Tree (DT) models have the best average accuracy, which is 98.8%, and 99.87 %, respectively.
The thermal dependence of the spectral response (i.e. transmission, reflection and time delay ( τ r ) responses) of uniform polymer optical fiber (POF) Bragg gratings has been investigated. In addition to the temperature dependence, the effects of grating strength (kL g ) and fiber index modulation ( ∆ n) have been investigated. Besides high capability of tunable wavelength due to the unique large and negative thermo-optic coefficient of POF, the spectral response for POF Bragg gratings show high stability and larger spectrum bandwidth with temperature variation compare with the silica optical fiber (SOF) Bragg gratings, especially with the increase of the kL g value. It was found that by increasing kL g , the peak reflectance value increases and the bandwidth of the Bragg reflector become narrower. Also it’s shown by increasing the kL g value, τ r deceasing significantly and reach its minimum value at the designed wavelength ( λ B ). Furthermore, the τ r for POF Bragg gratings is less than that for SOF Bragg gratings at the same value of kL g . Also it’s found that the peak reflectivity value increases to around 60% when the ∆ n value increases from 1 ˣ 10 -4 to 5 ˣ 10 -4 .
The traditional economic dispatch (ED) inattention to the fossil fuels emission of thermal power plants no longer satisfies the environmental needs. As a result of the non-convex, non-smooth fuel cost functions in addition to the nonlinearity of the emission modelling. These make the combined economic and emission dispatch (CEED) a highly nonlinear optimization problem. Furthermore, different operation process constraints should be taken into account, such as loss in electrical networks and power balance of unit operation. These constraints increase the difficulty of obtaining the global optimal solution based on traditional methods. Recently, meta-heuristic population-based algorithms have successfully become a beneficial technique for solving nonlinear optimization problems. The major contribution in this work is presenting a recent meta-heuristic approach known as Mayfly algorithm (MA) for solving nonlinear and complex CEED problem. The numerical results are compared with results obtained from modern meta-heuristic algorithms like Jellyfish Search (JS) optimizer, Dwarf mongoose optimization (DMO), Tunicate swarm algorithm (TSA), Red deer algorithm (RDA), Tuna Swarm Optimization (TSO), Golden Eagle Optimizer (GEO) and Bald eagle search Optimization algorithm (BES). The standard IEEE 30-bus test system is used in this article. The simulation results are done using MATLAB environment. The results approve the reliability, stability, and consistency of the proposed approach. The proposed technique gives reliable, robust, and high-quality solution with faster computational time. Moreover, MA is more suitable for solving nonlinear CCED problem because it has a considerable convergence feature.
Recently, face recognition technology has become more prevalent in various applications, including mobile devices, access control, and financial transactions. Therefore, it is crucial to address potential vulnerabilities that attackers might exploit. In this study, a method for face presentation attack detection (PAD) is introduced. The method utilizes the diversity of modalities provided by some cameras and sensors to detect face spoofing using convolutional neural networks (CNN) within the context of deep learning. To assess the effectiveness of the proposed approach in real-world scenarios, the wide multi-channel presentation attack (WMCA) dataset is used. The presented method exploits the multi-modal data, including RGB, depth, IR, and thermal channels, to enhance system performance and explore different techniques for combining the results from each modality. Furthermore, this study explores diverse techniques for fusing results from each channel in two fusion scenarios, pre-fusion and post-fusion. In the pre-fusion scenario, data from the four channels is combined, resulting in an ACER value of 0.19%. In the post-fusion scenario, the results of each modality are fused using different fusion techniques, such as majority voting, weighted voting, average pooling, and a stacking classifier. The stacking classifier yields the most favorable outcome with an ACER ratio of 0.03%. This performance is notably superior when compared to state-of-the-art methodologies.
In recent years, the urgent need for robotics applications in various sensitive work areas and high buildings has led to a significant development in the design of robots intended for climbing rough surfaces. Where, attention became focused on the ideal clinging mechanism. In this paper, a gripper of the climbing robot has been designed to achieve clinging on rough walls. The objective of this design is to be lightweight with high performance of clinging, therefore, a robot gripper has been designed based on a model of a limb inspired by the hand and claws of a cat, in which the robot claws were implemented by fishing hooks. These hooks are arranged in an arc so that each hook can move independently on the wall’s surface to increase the force of clinging to the rough wall. SolidWorks platform has been used to design the clinging limb and implemented using a 3D printer. In addition, the proposed design has been validated by performing several simulations using the SolidWorks platform. Experimental work has conducted to test the proposed design, and the results proved the success of the design.
This paper presents new device to simulate and inject a 4-20 mA current signal to PLC and control on this signal wirelessly. The proposed simulator device has been designed and implemented by a PIC 18f4520 microcontroller and an Ethernet click. This device is connected to Wireless Local Area Network (WLAN) via Wi-Fi router using TCP/IP protocol. The simulator has two channels for 4-20 mA current output signals with two channels for digital output signals, controlled by a laptop or a smart mobile. The purpose of this work is to demonstrate the usefulness of the Wi-Fi wireless technology for remote controlling on the 4-20 mA output current signal and the digital output signal in the designed simulator device. The experiments indicate that the proposed wireless simulator outputs the 4- 20 mA current with high accuracy and very fast response. The experiments also indicate that the proposed wireless simulator is easy, comfortable and convenient practically to use in the test operations of protections, interlocks and integrity of analog input channels for PLC compared to the wired simulator.
Increasing the penetration of Renewable Energy Sources (RES) into power systems created challenges and difficulties in the management of power flow since RES have variable power production based on their sources, such as Wind Turbines (WT), which depend on the wind speed. This article used Optimal Power Flow (OPF) to reduce these difficulties and to explain how the OPF can manage the power flow over the system, taking different cases of WT power production based on the different wind speeds. It also used Fixable AC Transmission (FACT) devices such as Thyristor-Controlled Series Compensators (TCSC) to add features to the controllability of the power system. The OPF is a non-linear optimization problem. To solve this problem, the artificial intelligence optimization technique is used. Particle Swarm Optimization (PSO) has been used in the OPF problem in this article. The Objective Functions O.F. discussed here are losses (MW), Voltage Deviation VD (p.u.), and thermal generation fuel Cost ($/h). This article used the wind turbine bus magnitude voltage and the reactance of TCSC as a control variable in OPF. To test this approach, the IEEE 30 bus system is used.