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Sliding Mode Vibration Suppression Control Design for a Smart Beam
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Active vibration control is the main problem in different structure. Smart material like piezoelectric make a structure smart, adaptive and self-controlling so, they are effective in active vibration control. In this paper piezoelectric elements are used as sensors and actuators in flexible structures for sensing and actuating purposes, and to control the vibration of a cantilever beam by using sliding mode control. The sliding mode controller (SMC) is designed to attenuate the vibration induced by initial tip displacement which is equal to 15 mm.  It is designed based on the balance realization reduction method where three states are selected for the reduced model from the 24th states that describe the cantilever beam according to the FEM. These states are most controllable and observable. The stability and control performance for the proposed SMC are proved using candidate Lyapunov function and the equivalent control concept. The control spillover, which is the sources of instability, is completely avoided as ensured within the control performance proof.

            Numerical simulations are preformed to test the vibration attenuation ability of the proposed SMC. For 15 mm initial tip displacement, the piezoelectric actuator was found able to reduce the tip displacement to about (0.2) mm within (2.5 s), while it is equal to (3.5) mm with the open loop case. Moreover, the induced chattering in system response, due to the discontinuous control action, is removed by approximating the signum function by a continuous arctan function. As a result  a smoother response are obtained with the same control performance as can be shown in the sliding variable, the control input voltage and the tip displacement plots.

 

 

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Publication Date
Fri Sep 24 2021
Journal Name
Arab World English Journal
A Pragma- Stylistic Analysis of Formal Congratulatory Letters in English and Arabic
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Politeness strategies are of significant importance to maintain the face of the addressee. Senders of formal congratulatory letters seek to create a positive image in the minds of their addresses by performing particular illocutionary acts and face-saving acts (FSAs) in the form of written texts. To the best knowledge of the researcher, this topic received little attention from linguistic researchers, especially on the pragma-stylistic level. The importance of this study arises from the fact that congratulatory formal letters are an effective tool in the successful performance of foreign relations and thus deserve investigation. The current study investigates the pragmastylistic aspects of illocutionary acts and FSA Politeness Stra

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Publication Date
Wed Dec 15 2021
Journal Name
Journal Of Baghdad College Of Dentistry
Odontogenic Cysts and Tumors of Maxilla and Maxillary Sinus (A Clinicopathological Analysis)
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Background: Knowledge about the prevalence and distribution of pathologies in a particular location is important when a differential diagnosis is being formulated. The aim of this study was to describe the prevalence and the clinicopathological features of odontogenic cysts and tumors affecting the maxilla and to discuss the unusual presentation of those lesions within maxillary sinus.

Materials and Methods: A multicenter retrospective analysis was performed on pathology archives of patients who were diagnosed with maxillary odontogenic cysts and tumors from 2010 to 2020. Data were collected with respect to age, gender and location.

Result: A total of 384 cases was identified, 320 (83.3%) cases were diagnosed as odontogenic

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Publication Date
Wed Jan 24 2024
Journal Name
Pharmacia
Novel anticoagulants in the management of atrial fibrillation: A comprehensive comparative analysis
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Background: Atrial fibrillation (AF) stands as the most prevalent cardiac arrhythmia, with associated risks of stroke and systemic thromboembolism. While vitamin K antagonists, specifically warfarin, have historically been the mainstay for stroke prevention in AF, they come with inherent limitations.

Aim: This review seeks to offer a comprehensive analysis of the efficacy, safety, and clinical advantages of novel oral anticoagulants (NOACs) compared to traditional warfarin in AF management.

Method: A meticulous examination of pivotal clinical trials, meta-analyses, and recent research publications was conducted.

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Publication Date
Sun Oct 01 2023
Journal Name
Optical Fiber Technology
A taper-in-etch based hybrid fiber Mach-Zehnder interferometer hydrogen sensor
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Publication Date
Sun Jan 01 2023
Journal Name
Communications In Mathematical Biology And Neuroscience
The dynamics of a delayed ecological model with predator refuge and cannibalism
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This study has contributed to understanding a delayed prey-predator system involving cannibalism. The system is assumed to use the Holling type II functional response to describe the consuming process and incorporates the predator’s refuge against the cannibalism process. The characteristics of the solution are discussed. All potential equilibrium points have been identified. All equilibrium points’ local stability analyses for all time delay values are investigated. The system exhibits a Hopf bifurcation at the coexistence equilibrium, which is further demonstrated. The center manifold and normal form theorems for functional differential equations are then used to establish the direction of Hopf bifurcation and the stability of the per

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Publication Date
Tue Jan 03 2023
Journal Name
College Of Islamic Sciences
Formulas The command and its style in Surat Al-Ma’idah is a rhetorical fundamentalist study.: The command and its style in Surat Al-Ma’idah is a rhetorical fundamentalist study
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Research Summary :

      Praise be to God, Lord of the Worlds, and prayers and peace be upon the Master of the Messengers, his family and all his companions, then after:

     This is a brief research that contained its two rudders the command and its Style in Surat Al-Ma’idah a fundamental rhetorical study, and the study clarified the meaning of imperative in both;  the Arabic  language and in the terminology of the fundamentalists and rhetoricians in a concise manner, and then indicated the imperative of the command , the true meaning, and the meanings interpretated as an  imperative form. I have mentioned some verses of Surat Al-Ma’idah, so what I have quot

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Publication Date
Sun May 17 2026
Journal Name
Al–bahith Al–a'alami
Foreign Series in the Kurdish Satellite Channels and Their Role in the Development of Awareness among Young People in the Kurdistan Region (Korean Series as a Model) (A Field Study on a Sample of Students of the Institute of Fine Arts in the City of Sulay
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The dubbing process for the Foreign Dramas by the Kurdish language became a serious phenomenon in the Kurdish satellite TV, especially in the past few years. It attracted a wide audience, especially young adolescents. And prepared by some breakthrough hostile to Kurdish culture and value coordinated by others remedy for the structural gaps and lapses have, as a result of climate which is brought into existence globalization and secretions variety dimensional, saturated value and cognitive effects bearing a strong identity of its elements. From here, the problem of this research is the ambiguity of their role in a series of developmental processes Kurdish awareness of young people and the extent of the impact that caused it.

This

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Publication Date
Thu Dec 31 2020
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Electronic payment methods used for salary resettlement and its impact on improving the mental image of customers: an applied study of the opinions of a sample of (private) commercial banks 'customers contracting with the Ministry of Higher Education and Scientific Research to localize employees' salaries
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The research seeks to identify the contemporary events that face the use of electronic payment methods to localize the salaries of state employees and its impact in enhancing the mental image of customers, and to achieve this purpose from the fact that a questionnaire was designed and distributed to an optional sample of (31) individual customers (employees) dealing With the researched private banks, it has been analyzed and reached a number of conclusions and recommendations, the most prominent of which is the lack of modernity of electronic payment methods by customers, which is reflected in the mental image of customers and the achievement of their satisfaction, in the Emiratization project for salaries needs an advanced leade

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Publication Date
Wed Mar 30 2022
Journal Name
Modern Sport
Effect of constant str ect of constant stretching ex etching exercises in impr cises in improving the elasticity ving the elasticity of cervical v vical vertebrae for patients with cer ae for patients with cervical spondylitis’ vical spondylitis’s for ages (40-50) years
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Practicing physical activity is a very necessary requirement for all segments of society. . Many individuals, regardless of environment, age and gender, are exposed to joint diseases and injuries and pain in the neck for many and varied reasons. Treatment methods and techniques vary according to the severity of the injury, as therapeutic exercises, including stretching exercises, specifically fixed ones, are one of the ways to eliminate cases of muscle and joint dysfunction. Many individuals, regardless of environment, age and gender, are exposed to joint diseases and injuries and pain in the neck for many and varied reasons. Treatment methods and techniques differ according to the severity of the injury, as therapeutic exercises, including

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Publication Date
Wed Mar 10 2021
Journal Name
Baghdad Science Journal
Study to modify the fat cow's milk for children and infants
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This study Ajert to modify the chemical composition of milk fat cows and make it similar to the installation of milk fat mother through the addition of protein and soybean oil to be given Alkhltatnsp sensory protein that the best plan is the ratio of 1:1

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