1,721,630 research outputs found
Interview with Abdo Mubasher
No full textفي هذه المقابلة، يتحدث عبده مباشر، الخبير الاستراتيجي، عن الضربة الأمريكية الأخيرة على العراق وكون صدام حسين السبب فيها. أجرى الحوار إبراهيم عابدين.In this interview, strategic analyst Abdo Mubasher addresses the current American assault on Iraq and Saddam Hussein's responsibility in it. The interview was conducted by Ibrahim Abdeen
Interview with Abdo Mubasher
No full textمقابلة مع الكاتب والصحفي المصري، عبده مباشر، يناقش فيها أزمة الخليج، والمعركة البرية والجوية التي قامت بها القوات العراقية ضد الكويت وتأثيرها علي الكويت والسعودية والعراق. قام بالمقابلة إبراهيم عابدين.An interview with Egyptian writer and journalist, Abdo Mubasher, in which he discusses the Gulf crisis, the ground and air battle waged by the Iraqi forces against Kuwait, and its impact on Kuwait, Saudi Arabia and Iraq. The interview was conducted by Ibrahim Abdeen
Design of Experiment based Factorial Design and Response Surface Methodology for MEMS Optim
No full texthis paper presents the application of the design of experiments technique based factorial designs and response surface methodology (RSM) for optimization of MEMS devices. The RSM methodology is used to optimize the geometric parameters of the symmetric toggle RF MEMS switch to minimize the switch pull-in voltage. Fractional factorial based Plackett–Burman screening design is developed and the corresponding pull-in voltage is obtained, through finite element method (FEM) based simulations, for different combinations of the dimensional parameters. Analysis of variance is performed to distinguish the most significant parameters affecting the output response. The significant parameters, obtained using Plackett–Burman screening design, are further investigated using second order Box–Behnken design to obtain the optimal levels of the significant parameters and analyze their interactions. Regression analysis is carried out to check the adequacy of the Box–Behnkan based response surface model for predicting the output response. The effect of the significant parameters and their interactions on the pull-in voltage is analyzed through model based 3D surface and contour plots. The optimal levels of the parameters for a pull-in voltage ≤15 V, with compact device dimensions, are determined and verified through FEM simulations. A comparison is made for the results obtained through RSM with the analytical results presented in the literature. This showed a close agreement, verifying the practicability of this approach for the optimization of MEMS devices
Design optimization of RF-MEMS switch considering thermally induced residual stress and process uncertainties
No full textThis paper presents the Design of Experiments (DOE) based parametric design optimization of the Symmetric Toggle RF-MEMS Switch (STS) for minimizing the actuation voltage considering the fabrication process uncertainties and thermally induced residual stress. Initially, three-dimensional (3D) non-linear Finite Element Method (FEM) models are developed and the formation of residual stress during the plasma etching step of the microfabrication process is explained using the Bauschinger effect. The pull-in voltage values and the switch profiles obtained after the thermal loading-unloading cycle in the FEM models are compared with the experimental values and optical profile measurements which showed a close agreement. A DOE based Dual Response Surface Methodology (DRSM) is implemented to identify the significant design parameters affecting the STS switch pull-in voltage in the presence of thermally induced residual stress. Two separate response surface empirical models are developed; one for the mean pull-in voltage and other for variation in the pull-in voltage due to microfabrication process tolerances. The developed response surface models are optimized simultaneously using the desirability function approach. The optimal levels of the design parameters that result in minimum pull-in voltage with increased insensitivity to process uncertainties are obtained using the direct search algorithm
Identifying Mubasher software products through sentiment analysis of Arabic tweets
No full textSocial media has recently become a rich resource in mining user sentiments. In this paper, Twitter has been chosen as a platform for opinion mining in trading strategy with Mubasher products, which is a leading stock analysis software provider in the Gulf region. This experiment proposes a model for sentiment analysis of Saudi Arabic (standard and Arabian Gulf dialect) tweets to extract feedback from Mubasher products. A hybrid of natural language processing and machine learning approaches on building models are used to classify tweets according to their sentiment polarity into one of the classes positive, negative and neutral. Firstly, document's Pre-processing are explored on the dataset. Secondly, Naive Bayes and Support Vector Machines (SVMs) are applied with different feature selection schemes like TF-IDF (Term Frequency-Inverse Document Frequency) and BTO (Binary-Term Occurrence). Thirdly, the proposed model for sentiment analysis is expanded to obtain the results for N-Grams term of tokens. Finally, human has labelled the data and this may involve some mistakes in the labelling process. At this moment, neutral class with generalisation of our classification will take results to different classification accuracy
Modeling and experimental verification of thermally induced residual stress in RF-MEMS
No full textElectrostatically actuated radio frequency microelectromechanical systems (RF-MEMS) generally consist of microcantilevers and clamped-clamped microbeams. The presence of residual stress in these microstructures affects the static and dynamic behavior of the device. In this study, nonlinear finite element method (FEM) modeling and the experimental validation of residual stress induced in the clamped-clamped microbeams and the symmetric toggle RF-MEMS switch (STS) is presented. The formation of residual stress due to plastic deformation during the thermal loading-unloading cycle in the plasma etching step of the microfabrication process is explained and modeled using the Bauschinger effect. The difference between the designed and the measured natural frequency and pull-in voltage values for the clamped-clamped microbeams is explained by the presence of the nonhomogenous tensile residual stress. For the STS switch specimens, three-dimensional (3D) FEM models are developed and the initial deflection at zero bias voltage, observed during the optical profile measurements, is explained by the residual stress developed during the plasma etching step. The simulated residual stress due to the plastic deformation is included in the STS models to obtain the switch pull-in voltage. At the end of the simulation process, a good correspondence is obtained between the FEM model results and the experimental measurements for both the clamped-clamped microbeams and the STS switch specimens
Experimental investigations of creep in gold RF-MEMS microstructuresSmart Sensors, Actuators, and MEMS VII; and Cyber Physical Systems
No full textLifetime prediction and reliability evaluation of micro-electro-mechanical systems (MEMS) are influenced by permanent
deformations caused by plastic strain induced by creep. Creep in microstructures becomes critical in those applications
where permanent loads persist for long times and thermal heating induces temperature increasing respect to the ambient.
Main goal of this paper is to investigate the creep mechanism in RF-MEMS microstructures by means of experiments.
This is done firstly through the detection of permanent deformation of specimens and, then, by measuring the variation
of electro-mechanical parameters (resonance frequency, pull-in voltage) that provide indirect evaluation of mechanical
stiffness alteration from creep. To prevent the errors caused be cumulative heating of samples and dimensional
tolerances, three specimens with the same nominal geometry have been tested per each combination of actuation voltage
and temperature. Results demonstrated the presence of plastic deformation due to creep, combined with a component of
reversible strain linked to the viscoelastic behavior of the material
Interview with Gamal Al-Ghitani, Gamal Badawi, Abdo Mubasher
No full textمقابلة مع الروائي المصري جمال الغيطاني رئيس القسم الأدبي بصحيفة الاخبار والكاتب الصحفي المصري جمال بدوى رئيس تحرير صحيفة الوفد المعارضة المصرية ونائب رئيس تحرير صحيفة الأهرام المصري عبده مباشر حول مناقشة مجموعة من القضايا منها أزمة الخليج وقضية التواجد الأجنبي بالمنطقة العربية. قام بالمقابلة إبراهيم عابدين.An interview with the Egyptian novelist Jamal Al-Ghitani, head of the literary section of Al-Akhbar newspaper, and the Egyptian journalist writer Jamal Badawi, editor-In-chief of the Egyptian opposition Al-Wafd newspaper, and deputy editor-In-chief of Al-Ahram newspaper, Abdo Mubasher, on a discussion of a group of issues, including the Gulf crisis and the issue of foreign presence in the Arab region. The interview was conducted by Ibrahim Abdeen
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