پروفیسر حامد حسن قادری
افسوس ہے کہ ادھر چند مہینوں کے اندر دنیائے علم و ادب کی کئی نامور ہستیوں، پروفیسر حامد حسن صاحب قادری، سید ہاشمی صاحب فرید آبادی اور مولانا صلاح الدین احمد نے انتقال کیا، پروفیسر حامد حسن صاحب قادری ہماری پرانی علمی بزم کی یادگار تھے، اردو اور فارسی زبان و ادب اور اس کی تاریخ پر ان کی نظر بڑی گہری اور وسیع تھی، تاریخ داستان اردو ان کی وسعت نظر کی شاہد ہے، وہ عرصہ تک سینٹ جانس کالج آگرہ میں اردو اور فارسی کے استاد رہے، ریٹائر ہونے کے بعد کراچی چلے گئے تھے، اور وہیں وفات پائی، ان کی وفات سے ایک پرانی علمی و تہذیبی یادگار مٹ گئی۔
(شاہ معین الدین ندوی، اگست ۱۹۶۴ء)
The learning of Arabic language like any other foreign language contains four main aspects; reading, writing, speaking and understanding while listening.[i] This learning process can be enhanced if the most appropriate Learning Strategy is used. In this paper the most appropriate Learning Strategy of Arabic Language is suggested. The course outlines for Arabic language are thoroughly studied and several professors and experts of Arabic Language from Pakistan, Egypt, Saudi Arabia and Sudan are interviewed. The author, who himself has vast experience in teaching Arabic language, also had the opportunity to sit in the Arabic language classes to observe various strategies and methodologies adopted by different professors while teaching Arabic. In this paper the time spent on teaching Arabic to the students is also discussed. The appropriate size of the class room i.e, the number of students in Arabic language class also matters in improving the quality of Arabic among the students. The matter of teaching Arabic in Arabic only or in the native language of the students will also be touched in here. As the time has changed and the world is moving ahead on a fast pace, it seems necessary to apply the “Direct Method” while teaching Arabic or any foreign language.[ii] This paper will shed light on what is meant by “Direct Method”. The idea of making the student sit and memorize the dry rules of grammar has become obsolete. The idea of telling the student what part of the phrase is subject or predicate, or what is object and what is a noun or verb, may come later. The idea of memorizing the bulk of new vocabulary in the beginning can also be postponed. Hence a paradigm shift is needed here while talking about the Methodology of Teaching Arabic Language, under the heading of “Direct Method”. [i] Muhammad Abdul Khaliq, Professor of Arabic and co-author of 'al-Arabia baina Yadaik'. The author of this research paper had a personal interview with him on 21.03.2014, in the Institute of Arabic Language, King Saud University, Riyadh, Saudi Arabia. [ii] This method is adopted roughly by some great scholars of Arabic language like Dr. V. Abdur Rahim who taught Arabic language for decades in the Islamic University of Madina, Kingdom of Saudi Arabia. The author was fortunate to meet with him many times and get benefitted from his experience. See for details: Abdurrahim, V. (1999), Arabic Course for English-Speaking Students, Leicester: UK Islamic Academy. See also: Abdullah, F. Ibrahim. (1999), Iqra Arabic Reader. Chicago: Iqra International Educational Foundation. Moreover see: Fawzan, Abdurrahman and others. (2004), Al-Arabia Baina Yadaik, Riyadh: Ministry of Education.
In the modern era of industrialization, power electronic converters have gained key importance due to their wide range of applications such as; use in arc furnaces, in duction heating systems, variable speed drives of motors, power supplies of various electronic systems, fluorescent lamps, elevators and cooling systems. Furthermore, the low-cost proliferation of power electronic devices due to the technological de velopments in the semiconductor industry has made them an attractive choice for integrating renewable energy resources. They are the essential and integral part of the systems providing solutions to issues like voltage sag, swell, frequency reg ulation, current sharing among different renewable energy resources, power factor correction and voltage regulation in different types of micro-grids. In all the above-mentioned applications, the robustness of the system under dif ferent load and line conditions depend upon the control algorithm of the power electronic converters. This is why the research in the field of power electronics has been focused on the control of power converters during the last decade. Among different types of control techniques, Sliding Mode Control (SMC) is renowned for its disturbance rejection and parameter invariant nature which makes it an irre sistible choice for controlling such systems. However due to physical constraints of the switching components, ideal condition of infinite frequency cannot be sat isfied. This causes the system to operate at finite but time varying switching frequency which is a serious issue for power electronic converters as they consist of passive components whose size and value depends upon the switching frequency. Moreover, the time varying switching frequency degrades the power quality and causes electromagnetic interference (EMI) issues in case of grid connected power converters. In the first phase of this research, a fixed frequency sliding mode controller uti lizing an integral sliding manifold is designed to improve the dynamic response of the power converter regulating the grid voltage, in the presence of unknown x load condition and uncertain network parameter of the micro-grid. A special purpose test rig is designed to experimentally validate the results in comparison with conventional PI controllers. In the second phase of the research, the power quality issues regarding DC micro grids are addressed. Power quality issues have been widely discussed regarding AC power systems but discussion regarding DC power quality in micro-grids is rare in research community because in past power transmission was carried out using AC systems only. However, in the recent years DC grids and transmission has emerged as an attractive solution to integrate renewable energy resources. Hence, to enhance the power quality, a fixed frequency SMC is proposed with harmonic cancellation and chattering reduction, using a PI type sliding manifold. Experimental results are presented to validate the theoretical derivations using the test rig. Finally, a new method based upon filter extraction of the equivalent control is proposed to fix the switching frequency in power converters controlled by SMC. The technique is implemented on a boost converter and the results are presented in comparison with PWM-SMC. Rigorous mathematical analysis is provided along with experimental results to validate the proposed technique.