s. mohammad ali zanjani

This study addresses the imperative for advanced gas sensors, particularly for monitoring ‎hazardous carbon monoxide (CO), by enhancing nanocrystalline SnO2 thin film fabrication. ‎Control of parameters in the sol-gel synthesis process is systematically explored to mitigate crack ‎formation and enhance SnO2 film quality on uncoated Al2O3 substrates. Leveraging SnO2's n-‎type semiconductor properties, traditional thin film methods are employed, with a specific focus ‎on overcoming drawbacks through glycerin. Among various fabrication techniques, sol-gel proves ‎cost-effective for producing high-quality, crack-free SnO2 layers tailored for gas sensor ‎applications. The study evaluates sensitivity to CO gas concentrations, improving structural ‎integrity, sensitivity, and stability. X-ray powder diffraction and SEM imaging confirm phase ‎purity and surface morphology, ensuring the absence of impurities or cracks. Integrated with ‎microcontroller-based circuits, the sensors exhibit rapid response and recovery times crucial for ‎real-time gas sensing. The addition of an output circuit with enhanced resolution and stability ‎further enhances sensor performance. Results demonstrate the proposed sensor's capability for ‎rapid response (less than 30 seconds) and recovery times (~39 seconds), crucial for real-time gas ‎sensing. Notably, the sensors demonstrate an admirable sensitivity with a minimum detection ‎limit of as low as 1 ppm of CO gas. Additionally, the study validates the sensor's stability and ‎reliability during prolonged exposure to N2 and 1% CO mixtures, highlighting its potential for ‎personal safety detectors and environmental safety monitoring.‎

This article introduces two designs for transresistance amplifiers. The first and second precision instrument amplifiers utilize ten and eight MOS transistors. Both proposed precision amplifiers were simulated with 0.18 µm CMOS technology and a supply voltage of ±0.7 V using Hspice software. According to the results, the Common Mode Rejection Ratio (CMRR) of the first precision amplifier can vary from 72.6 dB to 75.7 dB with a change in control voltage. In contrast, the second amplifier can range from 71.7 dB to 74 dB. The -3dB cutoff frequency for the CMRR of the first precision amplifier is accessible between 0.969 MHz and 16.4 MHz, and for the second precision amplifier, it ranges from 4.34 MHz to 40.8 MHz. The power consumption of the first proposed design varies from 203.33 µW to 372.77 µW within the adjustment range, and for the second proposed design, it changes from 234.57 µW to 338.73 µW. Time-domain analysis indicates that for a 20 µA(p-p) input signal, the maximum Total Harmonic Distortion (THD) at various frequencies for the first design is 3.37%. For the second design, it is 2.13%. The output impedance of the first proposed precision amplifier can vary from 779 to 1190 Ω with a change in control voltage, and for the second proposed amplifier, it can change from 860 Ω to 1640 Ω. Therefore, these two circuits are suitable for precision amplifier applications with electronic adjustability in medical instruments, biosensor reading circuits, electrocardiography, and signal processing.

In recent years, we have witnessed significant advancements in the production of solar cells with a reduction in cost and an increase in their efficiency. One of the stages in creating advancements in new cells is evaluating their performance under different conditions using simulations before their fabrication. In this article, the structure of a multi-junction solar cell composed of Ge layers, InAlGaAs alloys, and InAlGaP alloys will be comprehensively examined. To achieve the highest efficiency, the lowest absorbing layer of the solar cell (Ge solar cell) will initially be optically simulated and then electrically simulated. After optimizing the Ge solar cell, the intermediate layers between the cells (tunnel junctions) and then the upper absorbing layers will be optimized in sequence. Optimization of solar cells in each absorbing layer refers to selecting the appropriate thickness, impurity density, and molar percentage of the layers to achieve the highest efficiency. According to simulation results, an efficiency of over 49\% has been achieved for the 5-junction cell.

The unique properties of carbon monoxide and its high combustibility have led to the creation of various ‎sensors, such as electrochemical sensors and different circuits, to read its output. In this article, a deflection-type ‎Wheatstone bridge is used to measure changes in the sensor resistance, and the output voltage is connected to a 12-‎bit analog-to-digital converter through an adjustable precision amplifier. Next, a new method is proposed for self-calibrating the CO sensor. The Levenberg-Marquardt backpropagation algorithm (LMBP) is utilized in the Artificial ‎Neural Network model to minimize the Mean Squared Error (MSE) and identify the most suitable parameters in the ‎proposed method.‎‏ ‏The model under consideration has been developed and trained using real-time data.‎‏ ‏Based on ‎the experimental and evaluation outcomes, it can be concluded that the suggested model has an MSE value of ‎‎0.28249 and an R2 coefficient of determination of 0.99992, indicating high accuracy and precision. The proposed ‎sensor and calibration method have potential applications in various applications, including industrial and domestic ‎environments where CO monitoring is necessary.‎

Electromechanical oscillations in power systems usually exist due to incompatible conditions and disturbances in the network. Meta-heuristics using search strategy are used to find near-optimal solutions. Typically, the implementation of this approach involves the utilization of a fitness function to assess the candidate solutions. In nature-inspired metaheuristics optimization algorithms, an analogy from nature is used to generate approximate solutions for practical optimization problems. This work presents a comprehensive investigation into various nature-inspired optimization algorithms, including ant colony optimization, genetic algorithm, and bat algorithm. The primary focus of this paper is to explore their efficacy in the coordinated design of Power System Stabilizers (PSS) and Flexible Alternating Current Transmission Systems (FACTS). The objective of this coordinated design is to improve energy system stability and mitigate power system oscillations. Finally, new directions are provided to researchers who work in the field of applications of nature-inspired optimization algorithms and coordination configuration of PSS and FACTS regulators.

One of the important components and rotating equipment in the hydroelectric power plant is the hydro turbine. The rotation of the turbine converts the potential energy in the water into mechanical energy, and then the mechanical energy is converted into electrical energy by the generator. In this paper, the aim is to study the dynamic behavior of a production unit system with a water turbine and to investigate the effect of the loss compensator on the dynamic behavior of the system. In water units, a drop transient compensator is used for stable operation of speed control. The equations of the system are expressed in the state space and the real and oscillatory modes are determined using the system matrix. The simulation results show the stable state of the system due to step changes in the consumption load using the transient compensator. Also, bode diagrams confirm the transfer function of the system's frequency deviation in relation to the changes in the system's steady state load.

With the rapid progress of semiconductors in the level of voltage and power of the power system as well as the progress of control systems, compensators with high flexibility and performance range have been designed and built to increase the flexibility of energy transmission systems. to be These compensators installed in power systems are called flexible ac transmission systems (FACTS). One of the most important advantages of FACTS devices in the transmission system is to increase the transient stability margin of the power system by controlling the active and reactive power of the line during the occurrence of a fault in the system. In this article, the effect of one FACTS device with parallel connection, i.e. static compensator, on transient stability is investigated. The studied system is a two-machine power system including a hydropower plant and a local power plant. The simulation results show the effect of the compensator on the damping of electric power angle fluctuations. Also, the simulation results show the lack of influence of the compensator on the transmission active power in the transmission line. The simulation results have been obtained using Simulink MATLAB software.

In the present study, a new low-power and high-speed comparator circuit is designed in 65 nm fin field-effect transistor (FinFET) technology. Moreover, by properly using the capabilities of FinFET technology, the number of transistors is reduced, and subsequently, a smaller area is occupied. Replacing MOSFET transistors with FinFETs reduces the delay and power consumption of the circuit, so the overall performance is improved. The first innovation of the proposed design is that to reduce the size and power consumption, two transistors were removed and the back gates of two transistors were cross-coupled. The second innovation is the connection of back gates to other suitable points of the circuit that increase the speed of comparison. In this study, a supply voltage of 0.8 V is applied to the circuit to show that the proposed modifications with FinFET reduce the delay to 272 ps and power consumption to 6.7 µW.

In this paper, a new hybrid low-power and area efficient Carry Look-Ahead Adder in CNFET technology based on the full-swing Gate Diffusion Input (GDI) technique is proposed. The proposed CLA design in GDI logic style, not only decreases the circuit area effectively but also decreases the power consumption and delay parameters as well. The proposed design is simulated in HSPICE using the CNFET model parameters. Finally, the simulation results justify a good improvement in the circuit performance parameters such as power consumption, delay, chip size area and power-delay product (PDP) for the proposed CLA circuit.

One of the issues of reliable performance in the power grid is the existence of electromechanical oscillations between interconnected generators. The number of generators participating in each electromechanical oscillation mode and the frequency oscillation depends on the structure and function of the power grid. In this paper, to improve the transient nature of the network and damping electromechanical fluctuations, a decentralized robust adaptive control method based on dynamic programming has been used to design a stabilizing power system and a complementary static var compensator (SVC) controller. By applying a single line to ground fault in the network, the robustness of the designed control systems is demonstrated. Also, the simulation results of the method used in this paper are compared with controllers whose parameters are adjusted using the PSO algorithm. The simulation results show the superiority of the decentralized robust adaptive control method based on dynamic programming for the stabilizing design of the power system and the complementary SVC controller. The performance of the control method is tested using the IEEE 16-machine, 68-bus, 5-area is verified with time domain simulation.

Network On-Chip (NOC) includes a set of techniques and tools in the field of network design and their application to design System On-Chip (SOC). The performance, type, and dimensions of the topology are largely dependent on the switching method and the routing algorithms used in it, including deterministic or adaptive. In this paper, using service scheduling techniques and genetic programming in order of entry, round robin of data on selected chip-based networks and using a defined neural fuzzy system, an almost adaptive routing algorithm for two-dimensional NOC is presented. It is able to increase efficiency, reduce power consumption and increase reliability. In the proposed algorithm, the average latency in different traffic load conditions faced by each packet is much less than similar algorithms. The results show a relatively good improvement in routing modification, which makes this method usable and even competitive with other existing and successful routing methods, so that when the nodes are fixed, about %6 life network has been added.