پانی کی اہمیت و افادیت
تعارف(Introduction)
عربی میں پانی "ماء"کہلاتاہے۔ پانی زندگی کے بنیادی مادہ کی حیثیت رکھتا ہےتما م مشروبات کا سردار ہے، کائنات کا اصلی اور حقیقی عنصر ہے۔ آسمان پانی کے بخارت سے بنائے گئے ہیں جبکہ زمین اس کی جھاگ سے پیدا گئی ہے۔ اللہ تعالیٰ ہر چیز کو پانی کے ذریعے زندہ رکھا ہے۔
کائنات چار ارکان کا مرکب ہے جن میں ایک پانی ہے۔ جیساکہ علامہ الجاحظ ؒ لکھتے ہیں:
"الأركان الأربعة، التي هي الماء والأرض والهواء والنار"[1]
امام ابن قیم ؒ رقمطراز ہیں:
"مَاءٌ: مَادَّةُ الْحَيَاةِ، وَسَيِّدُ الشَّرَابِ، وَأَحَدُ أَرْكَانِ الْعَالَمِ، بَلْ رُكْنُهُ الْأَصْلِيُّ، فَإِنَّ السَّمَاوَاتِ خُلِقَتْ مِنْ بُخَارِهِ، وَالْأَرْضَ مِنْ زَبَدِهِ، وَقَدْ جَعَلَ اللَّهُ مِنْهُ كُلَّ شَيْءٍ حَيٍّ"[2]
مذکورہ عبارت سے صراحت ہوتی ہے، پانی مادہ حیات ہے جو آسمان، زمین اور ہر زندہ چیز کی تخلیق میں بنیادی حیثیت کا حامل قدرتی وسیلہ ہے۔
انسائیکلوپیڈیا آف بریٹانیکا میں ہے:
“Water, a substance composed of the chemical elements hydrogen and oxygen and existing in gaseous, liquid, and solid states. Water is one of the most plentiful and essential of compounds .”[3]
انسائیکلوپیڈیا آف ریلیجن کا مقا لہ نگار لکھتا ہے:
“Water is essential for man’s life ;it ensures his nourishment by fertilizing the land. It is more than nourishment ,since it is the source of nourishment.”[4]
آکسفورڈ انگلش ڈکشنری کے مطابق پانی (water) :
“The liquid of which seas, lakes, and rivers are composed ,and which as rains and issues from springs. When pure , it is transparent...
Tujuan penelitian ini adalah untuk mengetahui peningkatan kinerja guru di MTS Negeri 2 Banggai Semester 1 Tahun Pelajaran 2018/2019 setelah mengikuti supervisi akademik. Penelitian ini adalah penelitian tindakan sekolah. Subjek penelitian adalah guru di MTS Negeri 2 Banggai yang berjumlah 8 orang guru. Data kinerja guru pada penelitian ini dikumpulkan menggunakan kuesioner. Teknik analisis data menggunakan analisis deskriptif. Indikator keberhasilan penelitian ini adalah: apabila rata-rata kinerja guru minimal pada kategori Tinggi, dan ketuntasan klasikal sebesar 90%. Berdasarkan penelitian yang telah dilakukan dapat disimpulkan bahwa: penerapan supervisi akademik secara efektif dapat meningkatkan kinerja guru di MTS Negeri 2 Banggai Semester 1 Tahun Pelajaran 2018/2019. Hal ini ditunjukkan dari rerata kinerja guru sebelum penelitian sebesar 130, 50 berada pada kategori sedang, meningkat pada siklus I menjadi 150, 13 berada pada kategori tinggi dan meningkat lagi pada siklus II menjadi 167 berada pada kategori sangat tinggi
The present PhD dissertation has completed research on results related to flow behavior due to shear stress on the boundary of some Newtonian and non- Newtonian fluids under different circumstances. Firstly, we have discussed some concepts related to Newtonian and non-Newtonian fluids, constitutive equations, equations of motion and integral transforms. Secondly, we have presented the exact solutions of velocity, temperature and shear stress fields corresponding to some flows of Newtonian, second grade, Maxwell and Oldroyd-B fluids. We have established general solutions for the unsteady free convection flow of an incompressible viscous fluid due to an infinite vertical plate that applies a shear stress f (t) to the fluid, when thermal radiation and porous effects are considered. These general solutions may generate a large class of exact solutions corresponding to different motions with technical relevance. Some special cases are investigated under the effects of pertinent parameters on the fluid motion. Unsteady motion of second grade fluids induced by an infinite plate that applies a time-dependent shear stress f (t) to the fluid is also studied. General solutions may be reduced to new solutions of Newtonian fluids or they may be used to obtain known solutions from the literature. Furthermore, in view of an important remark, general solutions for the flow due to a moving plate may be developed. We have also studied the Couette flows of a Maxwell fluid caused by the bottom plate applying shear stress on the fluid. Exact expressions for velocity and shear stress corresponding to the fluid motion are determined using the Laplace transform. Two particular cases with constant shear stress on the bottom plate or sinusoidal oscillations of the wall shear stress are further discussed. Some important charac- teristics of fluid motion are highlighted through graphs. The unsteady motion of an Oldroyd-B fluid over an infinite flat plate is studied by means of the Laplace and Fourier transforms. After time t = 0, the plate applies cosine/sine oscillating shear stress to the fluid. The solutions obtained are presented viii as a sum of steady-state and transient solutions, which may easily be reduced to the similar solutions corresponding to Newtonian or Maxwell fluids. A central issue namely, obtaining the time for which the steady-state is reached is address by means of numerical calculations and graphical illustrations. The influence of oscillations frequency or of material parameters on this time corresponding to the steady-state is also analyzed. It is lower for cosine oscillations in comparison to sine oscillations of the shear, decreases with respect to ω and λ and increases with regard to λr .