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Go to Editorial ManagerIn this article, a hybrid optimization method has been proposed consisting of Adaptive Genetic Algorithms (AGAs) and Constrained Nonlinear Programming (NLP) to solve the problems of performance optimization of circular array antenna consisting paraOel center feeding short dipoles elements with two complex nonlinear optimization problems. In the first problem. the hybrid optimization algorithm is used to reduce the value of sidelobe level in the circular array radiation pattern by finding the oPtlmal values of the excitation coefficients of each element in the clrcular array. In the second problem, a synthesis of circular array with different forms of the desired radiation pattern is considered. Several examples are considered here to verify the validlty of this method. Comparisons were made between the results of this method and the results obtained by {SGA) Standard Genetic Algorithm, and it is clearly shown that this method is more efficient and flexible in solving the problems of performance optimization of circular array antenna .
The hybrid electric vehicle (HEV) is considered an effective technique to reduce fuel consumption and exhaust emissions. The effectiveness of the HEVs in reducing fuel consumption and exhaust emissions is required an accurate division of the total power demand between energy sources. This aim is reached by an accurate design of energy management strategy (EMS) in the HEVs. Dynamic programming is an effective strategy to found the optimal solution for energy management. This technique requires the driving cycle to be known previously, wherefore it's not suitable to implement in real-time. The Equivalent Consumption Minimization Strategy (ECMS) is an effective technique that can be implemented in real-time. This strategy is used to estimate and adapt the equivalent factor (EF) in real-time, which is used to convert the electric energy from the battery to equivalent fuel cost. The value of the (EF) varies with the driving cycle, therefore, the (EF) is suitable for a certain driving cycle and may lead to weak performance to another. This work proposed a technique based on the battery state of charge feedback called adaptive prediction (AP) to estimate and adapt the equivalent factor in real-time. The best-obtained results are ranged between (11.1 to 32.889) % for several different driving cycles.
Continuously Variable Transmission (CVT) combines the efficiency of manual transmissions with the driving comfort of automatic transmissions while providing an infinite range of gear ratios, improved fuel economy, and enhanced acceleration performance. This study presents a comparative evaluation of CVT performance against manual and automatic transmissions in a parallel hybrid electric vehicle (HEV), focusing on fuel consumption and exhaust emissions. A baseline HEV model equipped with a CVT gearbox was selected from ADVISOR simulation software and subsequently modified by replacing the CVT with manual and automatic transmissions for comparison. Exhaust emissions, including catalytic converter pollutant reactions, were recorded for all configurations. Performance assessments were conducted using several global standard driving cycles to simulate real driving conditions. Results indicated that the CVT configuration achieved superior fuel economy and a significant reduction in exhaust emissions compared with manual and automatic transmissions. This improvement is attributed to the CVT’s effective control of speed ratio and overall transmission efficiency. The findings support the suitability of CVT gearboxes for urban hybrid vehicle applications due to their low fuel consumption and high efficiency in speed ratio control.
In this paper, a new approach for the positioning (localization) of multi-node systems is presented. Each node including the beacon node contains two types of sensors: one for the distance sensing and the other type is for communication. The main idea of our proposed approach is to use the control of beacon to construct a nodes' tree which is going to be used later by the nodes to know the paths in which the information will flow. During the tree construction the identities of nodes will be known. Every node except the beacon will use the information obtained from its previous neighbor in the tree to find its own location and orientation. Several simulations using visual basic 2012 are implemented to discern the performance of this algorithm.
In this paper, a theoretical study of the conventional solar-still system integrated via the design of heat recovery of air exhausted from the air conditioner condenser employing heat exchangers (WHRUs) was conducted. This study aims to improve desalination performance by compensating for the non-existence of sunlight during the night. A comparison was made between the desalination performance in the event of exposure to solar radiation and its performance in the case of exposure to the system (WHRUs). It was found that the (WHRUs) system has a minimal impact on the production of the conventional desalination rig during the night period, as the highest cumulative productivity in the presence of the (WHRU S ) reached (2.15 kg) in August. In contrast, the productivity dependent on solar radiation was (4.58 kg) for the same month, with the most significant percentage of improvement reaching (31.91 %).
Lithium-ion batteries' physical properties classify them as one of the most important sources of clean energy that overcome the need for fuel usage. The rated operating temperature and its uniformity are of the main demands of Lithium-ion batteries. In this survey, several types of studies have been reviewed with the aim of understanding the thermal management systems used to control the temperature of lithium-ion batteries and their uniformity in the battery pack. They are represented by active and passive systems, as well as the hybrid system, which integrates each of the two mentioned systems into a system to obtain the best thermal performance. Active cooling systems were classified due to the type pf coolant used to air and liquid system, meanwhile passive system classified to PCM and heat pipe system. The survey reveals that the air-cooling of lithium-ion battery pack is better than the use of liquids. About 74% of the reviewed works prefer the use of active strategies. The working temperature under normal conditions should be within -20 to 60 °C, meanwhile the optimum range is 15 to 35 °C. The maximum temperature difference between batteries in the pack is preferred to be 5 °C or less.