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joe-676
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 Jan 01 2017
Journal Name
International Journal Of Economic Research
Credit derivatives: Do they matter to avoid credit exposure? (Some evidences from the US market)
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Credit derivatives (CDs) have been increasingly acknowledged as an important requirement to hedge and transfer credit risk CR. Nonetheless, they have been extensively criticized for destabilizing the whole economic system bringing about the latest subprime credit crisis. The study’s main aim is to investigate the reason for the use of (CDs), whether it is used for hedging or trade purpose, for four of the US international financial institutions that had made it through the 2007 crisis to resume functioning post-crisis. This will be for three different and critical periods, namely the pre, during and after crisis periods (Q1, 2000-Q1, 2014). Adopting the SUR technique, the investigation of the factors that influence the net position of (CD

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Publication Date
Fri Jun 15 2018
Journal Name
Преподаватель Xxi век
COMPARATIVE ANALYSIS OF TYPES OF METAPHORS OF RUSSIAN AND ARABIC LANGUAGES
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Metaphor is one of the most important linguistic phenomena of the artistic text, as it is the expression of the author’s emotions and evaluations, the result of a deep inner transformation of the semantic words and visual means of reflecting the national culture of each people. This paper examines the concept of linguistic metaphors and analyzes its types in the Russian and Arabic linguistics, provides a comparative analysis of metaphors in Russian and Arabic — all this allows to conclude that metaphorization is characteris- tic of different parts of speech. In the Russian language stylistic differentiation of the metaphors expressed more than in Arabic, so translation of many “sty- listic” metaphors from Russian into Arabic due to

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Publication Date
Mon Jun 22 2020
Journal Name
Baghdad Science Journal
Effects of Anthracene Doping Ratio and UV Irradiation Time on Photo-Fries Rearrangement of Polycarbonate
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Thin films of pure polycarbonate (PC) with anthracene doping PC films for different doping ratios (10, 20, 30, 40, 50 and 60 ml) were prepared by using a casting method. The influence of anthracene doping ratio on photo-fries rearrangement of polycarbonate was systematic investigated. Furthermore, pure PC and anthracene doping PC films were irradiated via UV light at a wavelength (254 nm) for different periods (5, 240, 288, and 360 hrs). The photo-fries rearrangement occurring in pure PC and anthracene doping PC films were monitored using UV and FTIR spectroscopies. The photo-fries rearrangement leads to scission the carbonate linkage and formation phenylsalicylate and dihydroxybenzophenes. The result of the UV spectrum confirms disappea

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Publication Date
Mon May 27 2019
Journal Name
Al-academy
Virtual Museums: Features and Characteristics: وعد عدنان محمود
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This research provides a study of the virtual museums features and characteristics and contributes to the recognition of the diversity of visual presentation methods, as the virtual museums give the act of participation and visual communication with programs at an open time, so that it would contribute to reflection, thinking and recording notes, developing the actual and innovative skills through seeing the environments. The study has been divided into two sections the first one is virtual museum techniques. The techniques were studied to reach the public and are used remotely by the services of personal computers or smart phones being virtual libraries that store images and information that was formed and built in a digital way and how

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Publication Date
Wed Jul 01 2015
Journal Name
Journal Of Educational And Psychological Researches
The impact of education differentiated strategy to modify the alternative conceptions Geographical concepts when students First grade average
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The aim of this study was to know ( the impact of education differentiated strategy to modify the alternative developments of geographical concepts when students first grade average) .
      To achieve the goal of this study , researcher relied on the experimental design of a partial set , the design is ( the experimental group with a control group of post-test )
.

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Publication Date
Sun Oct 01 2017
Journal Name
Journal Of Educational And Psychological Researches
The effect of using active learning model in the achievement of fourth -grade material in the de partment of physics teaching aids students and the development then critical thinking
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Goal  of  research  is  to  investigate  the  impact  of the  use  of  effective  learning  model in the  collection  of  the  fourth  grade  students/Department of  physics in the material  educational methods  and the  development  of  critical thinking  .to teach  this goal  has  been  formulated  hypothesis cefereeten zero  subsidiary  of the second hypothesis  .To  investigate  the  research  hypothesis  were  selected  sample  of  fourth-grade  students of the  department  of physics at the univers

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Publication Date
Sun Feb 01 2015
Journal Name
Journal Of Economics And Administrative Sciences
العلاقة بين نوعية حياة العمل والإبداع التنظيمي (بحث تطبيقي في ديوان وزارة التخطيط)
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    يهدف البحث الحالي إلى اختبار العلاقة بين نوعية حياة العمل والإبداع التنظيمي في ديوان وزارة التخطيط ، ولبلوغ الهدف المذكور وبناء على معطيات البحث الاستطلاعي للباحث بني ألانموذج الفرضي للبحث الذي ضم المتغير المستقل والمعتمد، واعتماداً على حركية الأنموذج صيغت فرضيتان، ولاختبار صحة الفرضيات وجمع المعلومات من عينة البحث البالغة (100) مدير يمثلون مرك

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Crossref
Publication Date
Sun Jan 01 2017
Journal Name
Journal Of Engineering
Effect of Air Bubbles on Heat Transfer Coefficient in Turbulent Convection Flow
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Experimental and numerical studies have been conducted for the effect of injected air bubbles on the heat transfer coefficient through the water flow in a vertical pipe under the influence of uniform heat flux. The investigated parameters were water flow rate of (10, 14 and 18) lit/min, air flow rate of (1.5, 3 and 4) lit/min for subjected heat fluxes of (27264, 36316 and 45398) W/m2. The energy, momentum and continuity equations were solved numerically to describe the motion of flow. Turbulence models k-ε was implemented. The mathematical model is using a CFD code Fluent (Ansys15). The water was used as continuous phase while the air was represented as dispersed. phase. The experimental work includes design, build and instrument a test

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Publication Date
Tue Jul 08 2025
Journal Name
Al–bahith Al–a'alami
THE RESPONSIBILITY OF INDEPENDENT IRAQI NEWSPAPERS IN PROMOTING THE VALUES OF CITIZENSHIP AND NATIONAL BELONGING IN THE SOCIETY: (An Analytical Study in the Opinion Articles in the Newspapers of Al-Sabah Al-Jadeed and Al-Mada)
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The research problem stems from a chief question: “What is the nature of the responsibility that «Al-Sabah Al-Jadeed» and «Al-Mada» Newspapers have undertaken in promoting the values of citizenship and national belonging in the society? The research aims to achieve a number of goals, including: Determining the most prominent themes that were emphasized in the opinion articles in these two newspapers within the framework of the responsibility of promoting the values ​​of citizenship and national belonging in society, and revealing the most prominent topics that were discussed in opinion articles in the two sample newspapers regarding the promotion of the mentioned values. This research is a desc

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Publication Date
Wed Apr 01 2015
Journal Name
Journal Of Educational And Psychological Researches
Analysis of Palestinian Ministry of Education Test Results in Mathfor Eighth Graders basic Public Schools in Tulkarm
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هدفت هذه الدراسة إلى تحليل نتائج الاختبار الوطني الموحد الذي تطبقه وزارة التربية والتعليم الفلسطينية في مادة الرياضيات لطلبة الصف الثامن الأساسي في المدارس الحكومية في محافظة طولكرم، وذلك لمعرفة مستوى الطلبة على هذا الاختبار في ضوء متغيرات الجنس والمنطقة التعليمية ونوع المدرسة، ومعرفة علاقة التحصيل على هذا الاختبار بتحصيل الطلبة المدرسي والمعدل العام. ولتحقيق ذلك تم تحليل درجات (3218) طالباً وطالبة؛ وهم ي

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