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Mehran Makhtoumi

Publications and source records attributed to Mehran Makhtoumi.

3 recordsLinked to original sources

Delay Mitigation in Air Traffic Flow Management

To mitigate ATFM delay, different approaches have been proposed so far which can be categorized into strategic and tactical domains. The strategical techniques mainly concern airport slot allocation and for the tactical domain, the ATFM function has several solutions available that range from the ground and air holding to rerouting actions, which have not gained significant efficiency in ATFM delay mitigation due to the fact that delays become apparent only on the tactical level when the strategic flight plan has been filled already. To tackle and address this problem there is a need for an algorithm that can synchronize strategical and tactical schedules. To fill this gap, in this paper the concept of fair buffer scheduling is proposed which can potentially contribute to strategical and tactical operations synchronization that would result in ATFM delay mitigation by increasing the system's robustness. The objective is to obtain an optimum fair and efficient buffer choice that mitigates ATFM delay and increases the stakeholders' welfare. Each appropriate and efficient approach requires a comprehensive understanding of the strategical buffer scheduling. This study presents a delay cost and flight buffer model that could be used for generating optimal buffer times to be considered as the initial population for the optimization problem to investigate the viability of employing fairness measures to obtain schedules with different trade-offs between cost, delay, and fairness.

physics.soc-ph

Active Vibration Control of Launch Vehicle on Satellite Using Piezoelectric Stack Actuator

Satellites are subject to various severe vibration during different phases of flight. The concept of satellite smart adapter is proposed in this study to achieve active vibration control of launch vehicle on satellite. The satellite smart adapter has 18 active struts in which the middle section of each strut is made of piezoelectric stack actuator. Comprehensive conceptual design of the satellite smart adapter is presented to indicate the design parameters, requirements and philosophy applied which are based on the reliability and durability criterions to ensure successful functionality of the proposed system, also fabrication process of the proposed piezoelectric stack actuator is discussed in detail. The coupled electromechanical virtual work equation for the piezoelectric stack actuator in each active strut is derived by applying D'Alembert's principle to calculate the consistent mass matrix, the stiffness matrix and the load vector using finite element approximation. Modal analysis is performed to characterize the inherent properties of the smart adapter and extraction of a mathematical model of the system. Active vibration control analysis was conducted using fuzzy logic control with triangular membership functions and acceleration feedback. The control results conclude that the proposed satellite smart adapter configuration which benefits from piezoelectric stack actuator as elements of its 18 active struts has high strength and shows excellent robustness and effectiveness in vibration suppression of launch vehicle on satellite.

physics.space-ph

Numerical Solutions of Heat Diffusion Equation Over One Dimensional Rod Region

Adaptive methods for derivation of analytical and numerical solutions of heat diffusion in one dimensional thin rod have investigated. Comperhensive comparsion analysis based on the homotopy perturbation method (HPM) and finite difference method (FDM) have been applied to the rod PDE system. The results show that performing HPM will eventuate more precision and satisfactory approximations at reasonable time than those obtained from FDM when compared to exact solution results. Also since solutions are originated from the problems in HPM thus it is convenient to express them with different functions which conclude that homotopy perturbation is a powerful numerical technique for solving partial differential equations.

physics.comp-ph