ڈاکٹر طہٰ حسین
افسوس ہے پچھلے دنوں عالمِ اسلام کی دو بلند پایہ اور نامور شخصیتیں ہم سے جُدا ہوگئیں، اوریہ دونوں مصری تھیں، ایک ڈاکٹر طہٰ حسین اوردوسرے شیخ ابوزہرہ۔اول الذکر بچپن میں ہی نابینا ہوگئے تھے لیکن اس کے باوجود علم وفضل اور ادب وانشاء میں وہ کمال پیدا کیا کہ نہ صرف مصرکے بلکہ مشرق کی ایک نامور شخصیت بن گئے۔ انھوں نے جامعۂ ازہر قاہرہ یونیورسٹی اورپھر فرانس میں تعلیم حاصل کی تھی، اس بناء پروہ کلاسکل اورجدید دونوں ادبیات کے مبصر اورصاحبِ فن نقاد تھے، ایک زمانہ میں پروفیسر مارگولیوتھ کی ہمنوائی میں انھوں نے اشعر الجاہلی کے نام سے جوکتاب لکھی تھی اس پر مصر میں ان کے خلاف اس قدر شدید ہنگامے ہوئے کہ لوگوں نے ان کاسوشل بائیکاٹ کردیا اور گورنمنٹ نے بھی کتاب کی اشاعت ممنوع قراردے دی۔اس کے بعد ڈاکٹر طہٰ حسین نے قابلِ اعتراض حصّہ کوخارج کرکے اسی کتاب کو الادب الجاہلی کے نام سے شائع کیا، اس کے علاوہ اورمتعدد کتب ، مثلاً حدیث الاربعاء تین جلدوں میں، علی ہامش السیرۃ، الشیخان، الفتنۃ الکبری، مراۃ الاسلام، الایام، وغیرہ مرحوم کی یادگار ہیں۔ لیکن ان کا اصل میدان ادبی تنقید تھا۔علاوہ ازیں وہ ایک خاص طرزِ تحریر کے بانی اور موجد تھے جس میں نسیم سحر کی لطافت، دریا کی روانی شعلہ کی لپک اورسیلِ رواں کی طاقت سب گھل مل گئے ہیں۔عرب کی نئی نسل کے ذہن اور فکر پرڈاکٹر طہٰ حسین کے قلم کے بہت گہرے اثرات ہیں اوراس حیثیت سے وہ بے شبہ عہدِ جدید کے ادبی معماروں میں ایک ممتاز مرتبہ ومقام کے مالک ہیں۔
[مئی ۱۹۷۴ء]
Islam has been discussed and criticized in the West by the name of Orientalism and this practice is in vogue in the modern enlightened age. While Orientalism remains to be an important chapter in the history of Islam and the West, new modes of approaching Islam, ranging from dialogue and critical understanding to confrontation and rejection, continue to make their appearances in various forms. Recently the West has started sponsoring some Muslims and ex-Muslims to criticize Islam besides the Orientalists. These so-called Muslims have been frequently appearing in the arenas of criticism for last few years. We may call these Muslims or ex-Muslims as ‘native Orientalists.’
The nano uids have gained tremendous signi cance due to their superior heat transfer properties. These enhanced heat transfer capabilities are promising for applications in thermal management systems and these translate into high energy e ciency, lower op- erating costs and better performance. An important mechanism of peristaltic activity for nano uid in Newtonian and non-Newtonian uids is considered. The heat transfer analysis in the absence of viscous dissipation can a ect the accurate ow simulations and measurements for the peristaltic transport. This necessitates taking the viscous dissipa- tion along with heat transfer analysis. Dissipation in return requires the viscosity to be variable being a strong function of temperature. Keeping this sequence in mind, viscous dissipation and variable properties of the uid in peristaltic transport of nano uids is discussed. Non-Newtonian uids have become a reality because the most physical u- ids are non-Newtonian in nature. These uids have very complex constitutive equations that raise the level of nonlinearity in the governing equation presenting mathematical di culty in addressing the non-linear equations. Therefore, the analysis of Newtonian uid is carried over to the non-Newtonian uid to understand the rheological properties of uid, and its use in industry. Electrically conducting uids have gained a great impor- tance and have been developed into a vast discipline of magnetohydrodynamics (MHD). MHD peristaltic ow is studied extensively with the view of its industrial and bio-medical applications, and its ability to suppress the uid velocity to avoid ow separation; how- ever, we feel that the study of magnetohydrodynamic ow of nano uids along with the temperature dependent viscosity is a missing link in the development of peristalsis that we aim to address in the present thesis. The importance of this study lies in its appli- cation in the targeted drug delivery for cancer patients, among others. In addition, we have incorporated the e ects of nonlinear thermal radiation which is generally ignored in literature or if considered; is taken as a linear approximation of radiative heat ux only. The peristaltic transport of nano uids has been the focus of this study. We start with the peristaltic ow of nano uid with temperature dependent viscosity under the e ect of x applied magneticeld. The e ects of induced magneticeld are also investigated which is a hallmark of strong magneticeld. This study in Newtonian uid is then extended to the non-Newtonian uid. The e ects of nonlinear thermal radiation are also explored. Emphasis in these studies is to incorporate the in uence of various parameters of physical importance on the peristaltic ow. Mathematical modeling of the problems is based on realistic assumptions and approximations for peristaltic transport. For nano uids, the formulation is completed in the presence of Brownian motion and thermophoresis. So- lutions are obtained by exact analytical and semi-numerical techniques. A comparative study between analytic and numerical solution is made for certainty. The results obtained are compared with existing literature wherever applicable. It is believed that this thesis will provide a profound understanding of peristaltic ows and lay a frame work for future investigations.