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Moussa Rabah,Djalab Yacine,Maache Mostefa,Khenata Rabah,Bin-Omran Saad,Rouf Syed Awais,Iqbal Muhammad Waqas,Abdiche Ahmed,Ahmed Waleed,Manzour Mumtaz 한국물리학회 2023 Current Applied Physics Vol.55 No.-
The wurtzite structure of the ZnO1-xTex ternary alloy was analyzed through the utilization of density functional theory (DFT) within the WIEN2k code. This investigation examines its structural, electronic, optical, and elastic properties. The results have indicated a nonlinear variation in the lattice constants of the alloy mixture. Moreover, the direct bandgap energies of the materials, including the binary mixtures ZnO and ZnTe, as well as their ordered alloy counterparts (ZnO0.75Te0.25, ZnO0.5Te0.5, and ZnO0.25Te0.75), substantiate the semiconducting characteristics of these compounds. The densities of the states (DOS) for ZnO and ZnTe binary compounds and ZnO0.75Te0.25 ternary alloy are chosen as prototypes. The reflectivity and absorption coefficients versus photon energy and the real and imaginary components concerning the refractive index are estimated at ternary alloys and their binary constituents. The ductile and brittleness nature of alloys are transformed with the composition, and they have strong ionic bonding.
Rabah, Mohammed,Rohan, Ali,Kim, Sung-Ho Korean Institute of Intelligent Systems 2018 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.18 No.2
This paper presents the modeling and control of a gyroscopic inverted pendulum. Inverted pendulum is used to realize many classical control problems. Its dynamics are similar to many real-world systems like missile launchers, human walking and many more. The control of this system is challenging as it's highly unstable which will tend to fall on either side due to the gravitational force. In this paper, we are going to stabilize the gyroscopic inverted pendulum using PID controller, fuzzy logic controller and fuzzy PID controller. These controllers will be compared to determine the performance and to distinguish which one has the better response. Experiments and simulations are conducted to examine the different controllers and results are presented under different disturbance scenarios.
Design of the propelling nozzles for the launchers and satellites
Rabah Haoui 한국항공우주학회 2014 International Journal of Aeronautical and Space Sc Vol.15 No.1
The aim of this work is to determine supersonic nozzle profiles that are used in propulsion, for launchers or embarked with satellites. This design has the role of firstly, providing important propulsion, i.e. with uniform and parallel flow at exit; and secondly, to find short length profiles, without modification of the flow in the nozzle. The first elaborate program is used to determine the profile of the divergent, by using the characteristics method for an axisymmetric flow. The second program is conceived by using the finite volume method, to determine and test the profile found connected to a convergent.
Adaptive Control of Bilateral Teleoperation System with Compensatory Neural-Fuzzy Controllers
Rabah Mellah,Said Guermah,Redouane Toumi 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.4
This paper presents two adaptive neural-fuzzy controllers equipped with compensatory fuzzy control inorder to adjust membership functions, and as well to optimize the adaptive reasoning by using a compensatorylearning algorithm. To the first controller is applied compensatory neural-fuzzy inference (CNFI) and to the secondcompensatory adaptive neural fuzzy inference system (CANFIS). Each controller is incorporated into a two channelbilateral teleoperation architecture involving force-position scheme, which combines the position control of theslave system with force reflection on the master. An analysis of stability and transparency based on a passivityframework is carried out. The resulting controllers are implemented on a one degree of freedom teleoperationsystem actuated by DC motors. The experimental results obtained show a fairly high accuracy in terms of positionand force tracking, under free space motion and hard contact motion, what highlights the effectiveness of theproposed controllers.
Effect of Mesh Size on the Viscous Flow Parameters of an Axisymmetric Nozzle
Rabah Haoui 한국항공우주학회 2011 International Journal of Aeronautical and Space Sc Vol.12 No.2
The viscous flow in an axisymmetric nozzle was analyzed while accounting for the mesh sizes in both in the free stream and the boundary layer. The Navier-Stokes equations were resolved using the finite volume method in order to determine the supersonic flow parameters at the exit of the converging-diverging nozzle. The numerical technique in the aforementioned method uses the flux vector splitting of Van Leer. An adequate time stepping parameter, along with the Courant, Friedrich, Lewis coefficient and mesh size level, was selected to ensure numerical convergence. The boundary layer thickness significantly affected the viscous flow parameters at the exit of the nozzle. The best solution was obtained using a very fine grid, especially near the wall at which a strong variation of velocity, temperature and shear stress was observed. This study confirmed that the boundary layer thickness can be obtained only if the size of the mesh is lower than a certain value. The nozzles are used at the exit of the shock tube in order to obtain supersonic flows for various tests. They also used in propulsion to obtain the thrust necessary to the displacement of the vehicles.
Design of the propelling nozzles for the launchers and satellites
Haoui, Rabah The Korean Society for Aeronautical and Space Scie 2014 International Journal of Aeronautical and Space Sc Vol.15 No.1
The aim of this work is to determine supersonic nozzle profiles that are used in propulsion, for launchers or embarked with satellites. This design has the role of firstly, providing important propulsion, i.e. with uniform and parallel flow at exit; and secondly, to find short length profiles, without modification of the flow in the nozzle. The first elaborate program is used to determine the profile of the divergent, by using the characteristics method for an axisymmetric flow. The second program is conceived by using the finite volume method, to determine and test the profile found connected to a convergent.
Autonomous Vision-based Target Detection and Safe Landing for UAV
Mohammed Rabah,Ali Rohan,Muhammad Talha,남강현,김성호 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.6
Target detection is crucial for many applications of Unmanned Aerial Vehicles (UAVs) such as search and rescue, object transportation, object detection, inspection, and mapping. One of the considerable applications of target detection is the safe landing of UAV to the drone station for battery charging and its maintenance. For this, vision-based target detection methods are utilized. Generally, high-cost cameras and expensive CPU’'s were used for target detection. With the recent development of Raspberry Pi (RPi), it is possible to use the embeddedsystem with cheap price for such applications. In the current research, RPi based drone target detection and safe landing system are proposed with the integration of PID controller for target detection, and Fuzzy Logic controller for safe landing. The proposed system is equipped with a USB camera which is connected to RPi for detecting the target and a laser rangefinder (LIDAR) for measuring the distance for safe landing. To verify the performance of the developed system, a practical test bench based on a quadcopter and a target drone station is developed. Severalexperiments were conducted under different scenarios. The result shows that the proposed system works well for the target finding and safe landing of the quadcopter.
On the Boundedness of Marcinkiewicz Integrals on Variable Exponent Herz-type Hardy Spaces
Heraiz, Rabah Department of Mathematics 2019 Kyungpook mathematical journal Vol.59 No.2
The aim of this paper is to prove that Marcinkiewicz integral operators are bounded from ${\dot{K}}^{{\alpha}({\cdot}),q({\cdot})}_{p({\cdot})}({\mathbb{R}}^n)$ to ${\dot{K}}^{{\alpha}({\cdot}),q({\cdot})}_{p({\cdot})}({\mathbb{R}}^n)$ when the parameters ${\alpha}({\cdot})$, $p({\cdot})$ and $q({\cdot})$ satisfies some conditions. Also, we prove the boundedness of ${\mu}$ on variable Herz-type Hardy spaces $H{\dot{K}}^{{\alpha}({\cdot}),q({\cdot})}_{p({\cdot})}({\mathbb{R}}^n)$.