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باب دوم: ماحولیاتی تحفظ کا مطالعہ

ماحولیات کا تعارف

ماحول کو عربی زبان میں "بیئۃ" کہا جاتا ہے۔ ا س کا مادہ "بوأ " ہے۔

صاحب "معجم الوسیط" رقمطراز ہیں:

" (البيئة) الْمنزل وَالْحَال وَيُقَال بيئة طبيعية وبيئة اجتماعية وبيئة سياسية"[1]

 احمد بن خلیل اپنی تالیف "کتاب العین" میں کرتے ہیں:

"بوأ:الباءةُ والمَباءة: منزل القوم حين يَتَبَوَّءُونَ في قِبَلِ وادٍ، أو سَنَد جَبَلٍ، ويقال: [بل هو] كلّ منزلِ يَنْزِلُه القَوْم، يقال: تَبَوَّءُوا منزلا.. وقال تعالى: وَلَقَدْ بَوَّأْنا بَنِي إِسْرائِيلَ مُبَوَّأَ صِدْقٍ "[2]

 ابو نصر فارابی ؒ لکھتے ہیں:

"[بوأ]المباءة: منزل القوم في كل موضع، ويسمى كِناس الثور الوحشي: مباءةً "[3]

احمد بن فارس الرازی رقمطراز ہیں:

" (بَوَأَ) الْبَاءُ وَالْوَاوُ وَالْهَمْزَةُ أَصْلَانِ: أَحَدُهُمَا الرُّجُوعُ إِلَى الشَّيْءِ، وَالْآخَرُ تَسَاوِي الشَّيْئَيْنِ.فَالْأَوَّلُ الْبَاءَةُ وَالْمَبَاءَةُ، وَهِيَ مَنْزِلَةُ الْقَوْمِ"[4]

ابن الاثیرؒ (م606ھ) ماحول کی لغوی تشریح فرماتے ہیں:

"مَنْ كَذب عَلَيَّ مُتَعَمِّداً فَلْيَتَبَوَّأْ مَقعده مِنَ النَّارِ قَدْ تَكَرَّرَتْ هَذِهِ اللَّفْظَةُ فِي الْحَدِيثِ، وَمَعْنَاهَا لِيَنْزِلْ مَنْزِلَه مِنَ النَّارِ، يُقَالُ بَوَّأَهُ اللَّهُ مَنْزِلا، أَيْ أسْكنَه إيَّاه، وتَبَوَّأْتُ منزِلا، أَيِ اتَّخَذْته، والمَبَاءَة: الْمَنْزِلُ"[5]

مذکورہ بالا مباحث سے معلوم ہوتا ہے کہ ٹھکانہ، مسکن، ارد گرد کے مقامات، رہائش کا مقام وغیرہ ماحول کے مفہوم میں شامل ہیں۔ "بَوَّأَ" کا معنی ٹھکانہ، قیام کی جگہ، منزل، مسکن، رہنے سہنے کامقام یعنی ماحول ہے۔ماحول اتنا اہمیت کا حامل ہے کہ کتاب اللہ میں بھی ماحول کو مختلف زاویوں سے ذکر کیا گیاہے۔ کلام ِ ربانی میں ماحول کے تذکرہ سے اس کی افادیت کا اندازہ کیا جاسکتا ہے۔

 ارشاد باری تعالیٰ ہے:

" وَالَّذِيْنَ هَاجَرُوْا فِي اللّٰهِ مِنْۢ بَعْدِ مَا ظُلِمُوْا لَنُبَوِّئَنَّهُمْ...

شخصية الصحابة في شعر صدر الإسلام

The literature represents the nation’s treasure of poetry and prose and its original heritage. It is the outcome of minds believe fully in its right to develop along with other nations. Poetry is one of the fields of heritage which observe human activity in the Arab environment and records the nation’s deeds everywhere by its pure tongue. For all these reasons it is concluded that the poetry which was generated with the advent of Islam especially the poetry of the prophet’s honorable companions who represented the first generation in Islam who were imparted education in Prophet’s school. This subject of research appealed to know their ideas in their poetry. In this regard, poetical works of poets of the early stage of Islam was started. The research consists of a preface, two objects of research and a conclusion. In the first object of research it has been discussed the introduction of the Prophet’s companion’s personality, concerning linguistically, technical and conceptual views, their attitude, and the nature of his role in the call for Islam, their role in learning Holy Qur’an by heart, Islam and honorable Prophet’s attitude towards poetry and poets. Whereas the second object of research is, it has been discussed the sensual ideology aspect in one topic such as, Jihad.

Design and Analysis of Metasurfaces for Polarization Conversion of Electromagnetic Waves

Control and manipulation of polarization state of electromagnetic waves has always been of interest in the scientific community due to its fundamental role in wide range of applications including contrast imaging microscopy, optical sensing, molecular biotechnology and optical and microwave communication. Although, conventional techniques are applied for polarization control using natural materials such as optical activity of crystals, Faraday-effect and solutions of chiral molecules such as sugar. However, such methods generally result in bulky volumes, narrow bandwidth and incidence angle dependent response which greatly limit their use for many practical applications. Therefore, scientists have explored the use of artificial structures in the form of ultra-thin metasurfaces to achieve miniaturized polarization control devices with wide bandwidth and angularly stable response. However, most of these designs achieve polarization conversion for normal incidence only, which practically becomes prohibitive, as incoming waves can have arbitrary incidence angles. Thus, metasurfaces with stable response for arbitrary incidence angles are highly desirable. In this perspective, there are two main objectives of this research thesis: firstly, to realize wideband metasurfaces achieving polarization conversion both for normal as well oblique incidence and secondly, to design metasurfaces which can achieve multiple functionalities through a single structure. The first three metasurface designs presented in Section I achieve angularly stable (maximum up to 60o) wideband cross-polarization conversion in reflection mode. The cross-polarization conversion is achieved through anisotropy of the unit cell while the bandwidth is extended through multiple plasmonic resonances. Multifunctional metasurfaces are presented in Section II. These metasurfaces are extremely desirable in practical applications as they can replace multiple optical components, thus miniaturizing size and reducing the cost of the overall system. The first of the multifunctional metasurfaces presented in this thesis, not only transforms linear and circular polarization to their corresponding cross polarization, but also achieves linear-to-circular and circular-to-linear polarization conversion in different frequency regimes.Thus, it exhibits both half- and quarter-wave plate operations in different frequency bands using an ultra-thin bilayer anisotropic metasurface. The final design presented in this thesis is based on a flexible single layer anisotropic metasurface manifesting both quarter-wave plate and half-mirror (1:1 beam splitter) operation.
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