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Variable Structure Control Design for a Magnetic Levitation System
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In this paper the variable structure control theory is utilized to derive a discontinuous controller to the magnetic levitation system. The magnetic levitation system model is considered uncertain, which subjected to the uncertainty in system parameters, also it is open-loop unstable and strongly nonlinear. The proposed variable structure control to magnetic levitation system is proved, and the area of attraction is determined. Additionally, the chattering, which induced due to the discontinuity in control law, is attenuated by using a non-smooth approximate. With this approximation the resulted controller is a continuous variable structure controller with a determined steady state error according to the selected control parameters. Finally the ability and the effectiveness of the proposed continuous variable structure controller to the magnetic levitation system are verified via numerical simulations. When state initiated inside the area of attraction, the results show that the ball position can be directed to follow various desired positions, with steady state error not exceeding .  

 

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Publication Date
Sun Jun 12 2011
Journal Name
Baghdad Science Journal
Superconducting Properties of the (Bi0.8Pb0.2)2(Sr0.9Ba0.1)2 Ca2Cu3-x Nix O10+? System.
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The effect of substitution of Ni on Cu in (Bi0.8Pb0.2)2(Sr0.9Ba0.1)2 Ca2Cu3-x Nix O10+? for (x=0,0.1….1,2,3) superconductor system and sintering time has been investigated .The samples were prepared by solid-state reaction methods. The results show that the optimum sintering temperature is equal to 850 ºC, and the sintering time is equal to 140 h. The highest transition temperature (Tc) obtained for (Bi0.8Pb0.2)2(Sr0.9Ba0.1)2 Ca2Cu3-x NixO10+? composition was 113 with x=0.8 Phase analyses of the samples by X-ray diffraction (XRD) analysis showed an orthorhombic structure with a high Tc phases (2223) as a dominant phase and low Tc phase (2212) in addition to some impurity phases.

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Publication Date
Tue May 30 2023
Journal Name
Iraqi Journal Of Science
Ground State Structure of Helium and Phosphorus Isotopes using the Radial Wave Functions of Harmonic-Oscillator and Hulthen Potentials
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     The ground state density distributions and electron scattering Coulomb form factors of Helium (4,6,8He) and Phosphorate (27,31P) isotopes are investigated in the framework of nuclear shell model. For stable (4He) and (31P) nuclei, the core and valence parts are studied through Harmonic-oscillator (HO) and Hulthen potentials. Correspondingly, for exotic (6,8He) and (27P) nuclei, the HO potential is applied to the core parts only, while the Hulthen potential is applied to valence parts. The parameters for HO and Hulthen are chosen to reproduce the available experimental size radii for all nuclei under study. Finally, the CO component of electron scattering charge form factors are also investigated. Unfortunately, there is no

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Publication Date
Sun Oct 01 2017
Journal Name
Journal Of Alloys And Compounds
Probing the effects of thermal treatment on the electronic structure and mechanical properties of Ti-doped ITO thin films
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Publication Date
Sat Oct 01 2022
Journal Name
Digest Journal Of Nanomaterials And Biostructures
Preparation and study effect of vacuum annealing on structure and optical properties of AgCuInSe<inf>2</inf> thin film
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Publication Date
Tue Jan 01 2019
Journal Name
Izvestiya Of Saratov University. New Series. Series: Philology. Journalism
To the Question of Internal Inflection of the Roots in Arabic and Russian (Inflected Analysis of the Root Structure)
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Publication Date
Tue Jul 06 2021
Journal Name
Animals
Comparison of the Genetic Structure of Invasive Bigheaded Carp (Hypophthalmichthys spp.) Populations in Central-European Lacustrine and Riverine Habitats
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Bigheaded carps (bighead carp, Hypophthalmichthys molitrix, and silver carp, Hypophthalmichthys nobilis) and their hybrids play an important ecological and economic role in their original habitat, while their introduced stocks may pose serious ecological risks. To address questions about the persistence and invasiveness of these fish, we need to better understand their population structures. The genetic structures of bigheaded carp populations inhabiting Lake Balaton and the Tisza River were examined with ten microsatellite markers and a mitochondrial DNA marker (COI). The Lake Balaton stock showed higher genetic diversity compared with the Tisza River stock. Based on hierarchical clustering, the Tisza population was characterized o

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Publication Date
Wed Sep 01 2010
Journal Name
Materials &amp; Design
Influence of glass addition and sintering temperature on the structure, mechanical properties and dielectric strength of high-voltage insulators
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Publication Date
Sun Mar 15 2026
Journal Name
Arab World English Journal
A Social Semiotic Analysis of Instagram as a Multimodal Platform for Supporting EFL Learners
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Social media has become an essential educational tool nowadays. Most existing research on digital learning in EFL contexts has primarily focused on traditional classroom-based instruction and less attention has been paid to social media platforms. The present study aims to fill the gap by using social semiotics to analyze four Instagram posts: two from BBC Learning English (@bbclearningenglish) and the other two from Learn English with Emma (@englishwithemma). Instagram posts are classified as multimodal texts with participatory and representational elements. The study adopts Kress and van Leeuwen’s (2005) Social Semiotic Multimodal Framework to analyze four purposely selected posters by answering the following research questions

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Publication Date
Wed Aug 30 2023
Journal Name
Al-kindy College Medical Journal
‘Peacock tail’ Clipping Technique for a Giant Middle Cerebral Artery Aneurysm: A Technical Note
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Background: Giant middle cerebral artery (MCA) aneurysms are surgically challenging lesions. Because of the complexity and variability of these aneurysms, a customized surgical technique is often needed for each case. In this article, we present a modified clip reconstruction technique of a ruptured complex giant partially thrombosed middle cerebral artery aneurysm.

Case description: The aneurysm was exposed using the pterional approach. Following proximal control, the aneurysm sac was decompressed. Then, we applied permanent clips to reconstruct the aneurysm neck. The configuration of the aneurysm mandated a tailored clipping pattern to account for resi

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Publication Date
Mon Aug 18 2025
Journal Name
Journal Of Genetic And Environment Conservation
Ultrasound application as a new green technology for preservation of table eggs: A review
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In recent years, there has been a significant increase in research demonstrating the new and diverse uses of non-thermal food processing technologies, including more efficient mixing and blending processes, faster energy and mass transfer, lower temperature and selective extraction, reduced thermal and concentration gradients, reduced equipment size, faster response to extraction control, faster start-up, increased production, and a reduction in the number of steps in preparation and processing. Applications of ultrasound technology have indicated that this technology has a promising and significant future in the food industry and preservation, and there is a wide scope for its use due to the higher purity of final products and the

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