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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
Sat Jan 01 2022
Journal Name
Iop Conference Series: Earth And Environmental Science
Natural Convection in Annulus Between Two Concentric Cylinders Partially Filled with Metal Foam Distributed with New Suggested Design
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Abstract<p>The investigation of natural convection in an annular space between two concentric cylinders partially filled with metal foam is introduced numerically. The metal foam is inserted with a new suggested design that includes the distribution of metal foam in the annular space, not only in the redial direction, but also with the angular direction. Temperatures of inner and outer cylinders are maintained at constant value in which inner cylinder temperature is higher than the outer one. Naiver Stokes equation with Boussinesq approximation is used for fluid regime while Brinkman-Forchheimer Darcy model used for metal foam. In addition, the local thermal equilibrium condition in the energy e</p> ... Show More
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Publication Date
Sun Sep 15 2019
Journal Name
Al-academy
Tourist Resting Units and their Design Methods in the Iraqi Marshlands: هدى محمود عمر -لقاء غازي حمد منصور
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    The study dealt with the design of tourist resting units in the Iraqi Marshes in contemporary design methods while preserving the heritage. The first chapter contained the research problem which is the important event of the inclusion of the Marshes in the World Heritage List. This research is important because it aims to develop the tourist reality of the Marshlands. The second chapter dealt with three sections the first of which is tourism in the marsh environment, the second one dealt with the structure of tourist space and the third dealt with the design methods of the tourist resting units in the Iraqi marshes.

The most important results of the research are the following: the sample models have taken desig

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Publication Date
Sun Feb 22 2026
Journal Name
Pakistan Journal Of Pharmaceutical Sciences
Optimization And Development Of Ondansetron HCl Nanocrystals By Using D-Optimal Design Expert® And In-Vitro Characterization
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Background: Over the last few years, nanocrystal technology has expanded to improve the bioavailability of poorly water-soluble drugs, which is challenging. Nanocrystals (NCs) exhibit many properties, such as enhancing drug solubility, dissolution, oral absorption, and high drug loading. Ondansetron hydrochloride (ONH) is an antiemetic drug that antagonizes a serotonin 5-HT3 receptor in the peripheral and central nervous system and is widely prescribed for the management of chemotherapy and radiotherapy-induced vomiting and nausea, as well as for postoperative nausea. ONH exhibits approximately 60% bioavailability due to its poor solubility and first-pass metabolism in the liver. Its solubility is pH-dependent, its precipitates abov

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Publication Date
Mon Mar 13 2017
Journal Name
Journal Of Baghdad College Of Dentistry
A study to compare the internal fitness and marginal gap between single crowns and crowns within three-unite bridge of zirconia substructure fabricated by CAD-CAM system. (An In vitro study)
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ABSTRACT Purpose: the aim of this in vitro study was to compare the marginal gap and internal fitness between single crowns and the crowns within three-unit bridges of zirconium fabricated by CAD-CAM system. Materials and methods: A standard model from ivoclar company was used as a pattern to simulate three-units bridge (upper first molar and upper first premolar) as abutments used to fabricate stone models, eight single crowns for premolar and eight of three units bridges. Crowns and bridges fabricated by CAD-CAM system were cemented on their respective stone models then sectioned at the mid-point buccolingaully and misiodistaly and examined under stereomicroscope. Result: the marginal gap in premolar crowns and premolar within bridge we

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Publication Date
Sat Sep 26 2026
Journal Name
Jornal Of Al-muthanna For Agricultural Sciences
A Proposed Approach to Agricultural Extension in Iraq for a Better Response to the Needs of farmer’s to Address Their Challenges
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Publication Date
Fri Sep 29 2023
Journal Name
International Journal Of Nanoscience
Preparation of N-A Cysteine-capped CdTe/CdS/ZnS core/shell/shell QDs as a Selective Probe for Detecting Damaged DNA
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In this study, NAC-capped CdTe/CdS/ZnS core/double shell QDs were synthesized in an aqueous medium to investigate their utility in distinguishing normal DNA from mutated DNA extracted from biological samples. Following the interaction between the synthesized QDs with DNA extracted from leukemia cases (represents damaged DNA) and that of healthy donors (represents undamaged DNA), differential fluorescent emission maxima and intensities were observed. It was found that damaged DNA from leukemic cells DNA-QDs conjugates at 585 nm while intact DNA (from healthy subjects) DNA–QDs conjugates at 574 nm. The obtained results from the optical analyses indicate that the prepared QDs could be utilized as probe for detecting disrupted DNA th

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Publication Date
Fri Jul 10 2026
Journal Name
Mathematical And Computational Applications
A Regularized Numerical Solution to an Inverse Coefficient Problem for the Forced Vibrations of a Cantilever Beam Equation Under Nonlocal Conditions
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This study tackles a fourth-order inverse problem involving a cantilever beam with nonlocal conditions to simultaneously calculate the beam’s displacement and an unknown time-dependent coefficient. A finite difference approach is suggested to discretize the hyperbolic fourth-order equation. A stability analysis for the proposed scheme is also provided. The indirect problem is the minimization of the misfit function. The goal of the minimization algorithm is to reduce the gap between the measured (noisy) data and the numerical computed solution provided by the model. To achieve stable results, Tikhonov’s regularization technique is employed, and two numerical test examples are shown to illustrate the suggested scheme's reliabilit

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Publication Date
Sun Dec 20 2020
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Negotiating policies for the granting of investment loans: A CASE STUDY ON IRAQI MIDDLE EAST BANK FOR INVESTMENT& COMMERCIAL GULF BANK
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The negotiation phase is gaining great importance in investment loans due to the magnitude of the amounts awarded and the need to obtain adequate lending guarantees and the development of better conditions, and this requires that negotiating policy with fixed principles that balance between meeting the demands of customers and maintain market share and achieve profits and avoid defaults and losses the bank, and so I have touched Find the concept of investment loans and procedures for granting and the concept of the negotiation process for the granting of loans. The practical side to ensure the preparation of examination form consists of questions commensurate with the methodology developed by the researchers, were directed to the officia

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Publication Date
Tue Dec 30 2025
Journal Name
Alnahrain Journal Of Legal Scienci
Elements and Conditions of Personal Civil Liability (Based on Fault) for the Government for Damages Caused by Demonstrations: A Comparative Study
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This study examines the position of comparative legislation (French legislation, English legislation, and Egyptian legislation) in addressing the regulation of personal civil liability (based on fault) for the government. About the damages caused by demonstrations in terms of their legal nature, their legal basis, and the pillars and conditions of that responsibility. Then, we explain the position of the Iraqi legislator and compare it with what is the case in the legislation mentioned above

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Publication Date
Fri Mar 17 2017
Journal Name
Elixir Mech. Engg. 109 (2017) 47879-47881, Www. Elixirpublishers. Com …‏
Effect of Cutting Angle for a Locally Assembling Motorized Vibration Cutter on Some Operational Characteristics Used for Date Palm Fronds Cutting
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