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Step-Up Asymmetrical Nine Phase Delta-Connected Transformer for HVDC Transmission
Ammar, Arafet Ben,Ammar, Faouzi Ben The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.6
In order to provide a source for nine phases suitable for 18-pulse ac to dc power, this paper proposes a new structure for a step-up asymmetrical delta-connected transformer for converting three-phase ac power to nine-phase ac power. The design allows for symmetry between the nine output voltages to improve the power quality of the supply current and to minimize the THD. The results show that this new structure proves the equality between the output voltages with $40^{\circ}-{\alpha}$ and $40^{\circ}+{\alpha}$ phase shifting and produces symmetrical output currents. This result in the elimination of harmonics in the network current and provides a simulated THD that is equal to 5.12 %. An experimental prototype of the step-up asymmetrical delta-autotransformer is developed in the laboratory and the obtained results give a network current with a THD that is equal to 5.35%. Furthermore, a finite element analysis with a 3D magnetic field model is made based on the dimensions of the 4kVA, 400 V laboratory prototype three-phase with three-limb delta-autotransformer with a six-stacked-core in each limb. The magnetic distribution flux, field intensity and magnetic energy are carried out under open-circuit operation or load-loss.
Step-Up Asymmetrical Nine Phase Delta-Connected Transformer for HVDC Transmission
Arafet Ben Ammar,Faouzi Ben Ammar 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.6
In order to provide a source for nine phases suitable for 18-pulse ac to dc power, this paper proposes a new structure for a step-up asymmetrical delta-connected transformer for converting three-phase ac power to nine-phase ac power. The design allows for symmetry between the nine output voltages to improve the power quality of the supply current and to minimize the THD. The results show that this new structure proves the equality between the output voltages with 40°- α and 40°+ α phase shifting and produces symmetrical output currents. This result in the elimination of harmonics in the network current and provides a simulated THD that is equal to 5.12 %. An experimental prototype of the step-up asymmetrical delta-autotransformer is developed in the laboratory and the obtained results give a network current with a THD that is equal to 5.35%. Furthermore, a finite element analysis with a 3D magnetic field model is made based on the dimensions of the 4kVA, 400 V laboratory prototype three-phase with three-limb delta-autotransformer with a six-stacked-core in each limb. The magnetic distribution flux, field intensity and magnetic energy are carried out under open-circuit operation or load-loss.
Effect of Four Flavonoids on Blood Glucose of Rats
Ammar, Nagwa M.,Al-Okbi, Sahar Y. The Pharmaceutical Society of Korea 1988 Archives of Pharmacal Research Vol.11 No.2
The effects of aglycones moring and quercetin and their corresponding glycosides quercitrin and rutin were studied on the blood glucose levels of rats. Quercetin and quercetrin caused hypoglycaemia in rats while rutin and morin showed almost no difference. Quercetin, which showed 50% pronounced hypoglycaemic effects, reduced significantly the blood glucose level of alloxan diabetic rats.
TOPOLOGICAL PROPERTIES OF GRAPHENE USING ψk- POLYNOMIAL
AMMAR ALSINAI,ANWAR ALWARDI,N.D.SONER 장전수학회 2021 Proceedings of the Jangjeon mathematical society Vol.24 No.3
Graphene is a two-dimensional material consisting of a single layer of carbon atom arranged in a honeycomb structure. Graphine exhibits important intrinsic properties such as high strength, excellent conductor of heat and electricity. In this research, k-polynomial, when k = 2 for the line graph of Graphene is established, the degree-based topological indices, such as first, second and third leap Zagreb indices are obtained. Accordingly, by using the derivative of 2- polynomial of Graphene the first, second leap hyper-Zagreb indices, and leap forgotten topological index of Graphene, are found.
Ammar A. Aldair,Auday Al‑Mayyahi,Abdulmuttalib T. Rashid 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.4
This article introduces a new control methodology to intelligently drive the motion of a mobile robot via given waypoints. A nonlinear model predictive controller (NMPC) is utilized to track the waypoints that are placed randomly at diferent positions in a given environment. Hence, various tracking paths can be generated based on locations of waypoints. Additionally, a Quadratic Bezier Curves algorithm has been applied for obstacle avoidance. It is combined with the NMPC via a switching mechanism. Hence, the transportation of the mobile robot will take the priority of avoiding obstructing obstacles if exist before moving forward to the next target waypoint. Single and multiple mobile robots have been simulated into several scenarios to investigate the performance of the developed control scheme.
SHECHTER SPECTRA AND RELATIVELY DEMICOMPACT LINEAR RELATIONS
Ammar, Aymen,Fakhfakh, Slim,Jeribi, Aref Korean Mathematical Society 2020 대한수학회논문집 Vol.35 No.2
In this paper, we denote by L the block matrix linear relation, acting on the Banach space X ⊕ Y, of the form ${\mathcal{L}}=\(\array{A&B\\C&D}\)$, where A, B, C and D are four linear relations with dense domains. We first try to determine the conditions under which a block matrix linear relation becomes a demicompact block matrix linear relation (see Theorems 4.1 and 4.2). Second we study Shechter spectra using demicompact linear relations and relatively demicompact linear relations (see Theorem 5.1).
Design of a Stable an Intelligent Controller for a Quadruped Robot
Ammar A. Aldair,Auday Al‑Mayyahi,Weiji Wang 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.2
Quadruped robots have increasingly been used in complex terrains where barriers and gaps exist. In this paper, a four-legged robot with intelligent controllers is designed and simulated. The designed architecture comprises 12 servo motors, three per leg, to provide considerable fexibility in movement and turning. Proportional Integral Derivative (PID) controllers and Fuzzy controllers are proposed to control and stabilize the motion of the quadruped robot. An ant colony optimization algorithm has been utilized to tune the parameters of the PID controller and the Fuzzy controller. After obtaining the optimal values of both controllers, the entire architecture is implemented using the Multibody Simscape package in MATLAB which models multidomain physical systems. The simulation results are conducted in a 3-dimensional environment and they are demonstrated in three case studies; frstly, when the system is simulated without using a controller which leads to a collapse of the quadruped robot. Secondly, when the PID controller is combined with the system, better movement is obtained. However, the quadruped is unable to complete its path and collapses after a few meters. Thirdly, when the Fuzzy controller is integrated into the designed architecture, a signifcant improvement is observed in terms of minimizing elapsed time and improving the overall performance of the motion. The stability of the Fuzzy controller has been examined using Lyapunov criteria to validate its overall performance. Comparisons are conducted based on control eforts and travelled distances to demonstrate the suitability and efectiveness of Fuzzy controllers over PID controllers.
Ammar Boulal,Tayeb Bensattalah,Abdelkader Karas,Mohamed Zidour,Houari Heireche,E.A. Adda Bedia 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.73 No.2
This paper investigates the buckling behavior of carbon nanotube-reinforced composite plates supported by Kerr foundation model. In this foundation elastic of Kerr consisting of two spring layers interconnected by a shearing layer. The plates are reinforced by single-walled carbon nanotubes with four types of distributions of uniaxially aligned reinforcement material. The analytical equations are derived and the exact solutions for buckling analyses of such type’s plates are obtained. The mathematical models provided, and the present solutions are numerically validated by comparison with some available results in the literature. Effect of various reinforced plates parameters such as aspect ratios, volume fraction, types of reinforcement, parameters constant factors of Kerr foundation and plate thickness on the buckling analyses of carbon nanotube-reinforced composite plates are studied and discussed.