Abstract: The efficiencies and performance of gas turbine cycles are highly dependent on
parameters such as the turbine inlet temperature (TIT), compressor inlet temperature (T1), and
pressure ratio (Rc). This study analyzed the effects of these parameters on the energy
efficiency, exergy efficiency, and specific fuel consumption (SFC) of a simple gas turbine
cycle. The analysis found that increasing the TIT leads to higher efficiencies and lower SFC,
while increasing the To or Rc results in lower efficiencies and higher SFC. For a TIT of
1400 ℃, T1 of 20 ℃, and Rc of 8, the energy and exergy efficiencies were 32.75% and 30.9%,
respectively, with an SFC of 187.9 g/kWh. However, for a TIT of 900 ℃, T1 of 30 ℃, and Rc
of 30, the energy and exergy efficiencies dropped to 13.18% and 12.44%, respectively, while
the SFC increased to 570.3 g/kWh. The results show that there are optimal combinations of
TIT, To, and Rc that maximize performance for a given application. Designers must consider
trade-offs between efficiency, emissions, cost, and other factors to optimize gas turbine cycles.
Overall, this study provides data and insights to improve the design and operation of simple
gas turbine cycles.
 

The static charges and induced voltages from extra-high-voltage alternating current transmission lines (EHVACTLs) on parallel oil pipelines (POPLs) raise the risk levels for people and animals. Thus, the objective of this paper was to reduce and/or mitigate the electric field which is concentrated on POPLs by using grounded shield wires under EHVACTLs. Three techniques are employed to reduce the electric field effects on POPLs of two distinct types of transmission lines (TLs), 500 kV and 220 kV. The first technique involves raising the tower’s height to improve the clearance space between the POPLs and the TL conductors. The second technique is increasing the horizontal distance between the POPLs and the nearest stressed conductors of the TL. The third technique involves placing shield wires beneath the stressed conductors of the EHVACTLs. The electric field under the EHVACTLs is calculated with and without the grounded shield wires using charge simulation method. The results of the first technique revealed that with increasing the tower height from 10 m to 15, 20, 25, and 30 m, the electric field decreased by 43.75%, 62.5%, 68.75%, and 75%, respectively. Herein, employing the second technique, the electric field intensity is reduced by 20% and 21% depending on the POPL placed at a distance from the right stressed conductor equal to the horizontal clearance between conductors of 500 kV and 220 kV, respectively. Besides, the results of the third technique proved that the shield wires under the EHVACTLs reduced the electric field intensity on the POPLs by 17.65% and 24.71% for 500-kV and 220-kV TLs, respectively.

The grounding scheme is one of the main elements for protection system to mitigate the effect of unwanted lightning strikes or operational failures due to faults in generation, transmission and distribution systems. Desert sand soil has a very low electric conductivity, causing weakness in grounding system. To mitigate problems, the soil is supported with a high conductivity agent to adjust the soil conductivity to acceptable levels. A high-cost and non-renewable commercial product can be added to soils to increase their conductivity. This study brings innovation to conventional soil-enhancement materials. A newly developed mixture is proposed, which is composed of waste-activated carbon received from water purification industries and wood ash from agricultural wastes. First, mixture samples with different compositions of available waste materials were prepared. Then, experimental tests were performed and optimized with a combined genetic algorithm (GA) and fuzzy ranking method to estimate the optimal percentage volume value of each material involved in the developed mixture. To validate the effectiveness of the developed mixture, the results were compared with a commercial product available in the market. Also, the obtained results using GA are compared with those obtained by particle swarm optimization (PSO) to appreciate the best GA solutions. The effectiveness of using the developed mixture and the commercial product in reducing the resistance-to-ground of a rod driven in high and low resistivity soils is evaluated. Finally, a sample of the developed mixture was checked to be non-corrosive material for copper grounding rods.

Among the important influences on grounding systems are soil resistivities, as well as climatic changes such as temperature and humidity. Previous scientific research in soil enhancement materials is constantly improving to reduce soil resistance, and then improve the grounding systems to ensure safety of people and public facilities against the risks of fault current leakage or lightning strike. This paper presents a review based on the scientific analysis of previous research in field of soil-enhancement materials and their types under the influence of low and transient (impulse) testing conditions. The traditional and recent soil-enhancement materials are rearranged and divided into three main categories (natural, chemical, and waste) according to their nature. Then, it will focus on methodology, field, and computational methods of measurement. In addition, the soil-enhancement materials evaluation in grounding system based on their advantages and drawbacks is reported.

This article proposes designing and dissection of the distribution Static compensator (D-STATCOM) to mitigate power quality problem like voltage swelling and sagging that happens due to symmetric and asymmetric faults. The DSTATCOM system presents comparison between two models the first was designed for three phases together to measure voltage of three phases and the second dealing with the every phase to measure voltage of single phase separately. D-Stacom model is designed to study its effect in the case of symmetric three phase faults and asymmetric faults like single line to ground (SLG) fault, line to line (LL), and double line to ground (DLG). The control system is carried out utilizing the Pulse Width Modulation technique and PID controller to reduce voltage swelling and sagging. Ant Colony Optimization (ACO) was used to adjust mechanism of the PID controller. ACO was applied to find the optimum gain parameter of PID controller. The performance of D-STATCOM in mitigation voltage sags and swells are showed with the aid of MATLAB Simulink. Results of D-STATCOM showed excellent and effective performance in mitigation voltage sags and swells.

his study aims to investigate how the electrical-resistivity of different soils and grounding enhancement-materials is influenced by water-content and the dehydration under ambient and high-constant temperatures. The used enhancement-materials were extracted from surrounding wastes in Egyptian desert. First, waste enhancement-materials, their developed-mixture and soil samples were prepared for experimental testing. The contact-resistance between soil and enhancement-material was measured by using a designed soil-box. It was observed that adding a wood-ash as an interface-layer between the soil and enhancement-materials decreased significantly the contact-resistance. The developed-mixture and wood-ash demonstrated highest water-content retention when compared against the other enhancement-materials. This maintains their resistivity values low to serve for grounding purpose. The wood

The Holy City of Mecca is the place where millions of people gather for religious rituals over the year, and despite the enormous administrative efforts directed to the administration of Congestion Management (CM) during the Hajj and the "Al Mashaaer days", there is always the possibility of introducing better services in subsequent years. This study has a practical outcome in this respect, as it aims to develop a methodological framework that can operate as a supportive tool in the administration of the Hajj, thus easing the movement of pilgrims in congested areas. The methodology acknowledges that the major areas of mobility in Mecca seem to be repetitive, with the leading destination being the Al Kaaba area and particular locations (hotels) being targeted at certain times (Prayer times). To support this mobility, the users and the drivers should be connected via a single platform based on an Artificial Intelligence algorithm (Reinforced Learning, for example). Such a strategy would optimize mobility in the area over time by learning from actions/decisions such as ridesharing matching, taxi dispatching, en-route guiding, and the generation of intermodal paths. That would help in providing solutions for real-time interaction. Decisions about departure times, paths to follow, modes of travel, and logistic freight movement would be available for all.

There is no doubt that the travel demand forecasting stage is the most crucial stage in any transportation project, with the aim of improving existing facilities or establishing one from scratch. Although transportation planners agree widely about the four conventional steps of demand forecasting, there are inherent debates about their algorithmic applications. This article gives a thorough review of the demand forecasting stages. In addition, a complete framework is given for the process of travel demand forecasting in multi-modal networks, which considers the interdependence between the forecasting steps and offers the ability to incorporate the advances of machine learning and transportation simulation programs for the sake of accuracy.