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Variational Improvement to Near-Minimal Surfaces and Comparison With Numerical Outputs of Exact Expressions

Thesis Info

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External Link

Author

Daud Ahmad

Program

PhD

Institute

University of the Punjab

City

Lahore

Province

Punjab

Country

Pakistan

Thesis Completing Year

2013

Thesis Completion Status

Completed

Subject

Mathemaics

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/2631/1/3104S.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727657664

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An algorithm using a suggested ansatz is presented to reduce the area of a surface spanned by a finite number of boundary curves by doing a variational improvement in the initial surface of which area is to be reduced. The anzatz we consider, consists of original surface plus a variational parameter multiplying the unit normal to the surface, numerator part of its mean curvature function and a function of its parameters chosen such that its variation at boundary points is zero. We minimize of its rms mean curvature and for the same boundary decrease the area of the surface we generate. We do a complete numerical implementation for the boundary of surfaces, a) when the minimal surface is known, namely a hemiellipsoid spanned by an elliptic curve (in this case the area is reduced for the elliptic boundary by as much as 23 percent of original surface), and b) a hump like surface spanned by four straight lines in the same plane- in this case the area is reduced by about 37.9141 percent of original surface along with the case when the corresponding minimal surface is unknown, namely a bilinearly interpolating surface spanned by four bounding straight lines lying in different planes. (The four boundary lines of the bilinear interpolation can model the initial and final configurations of re-arranging strings). This is a special case of Coons patch, a surface frequently encountered in surface modelling- Area reduced for the bilinear interpolation is 0.8 percent of original surface, with no further decrease possible at least for the ansatz we used, suggesting that it is already a near-minimal surface. As a Coons patch is defined only for a boundary composed of four analytical curves, we extend the range of applicability of a Coons patch by telling how to write it for a boundary composed of an arbitrary number of boundary curves. We partition the curves in a clear and natural way into four groups and then join all the curves in each group into one analytic curve by using representations of the unit step function including a fully analytic suggested by us. Having a well parameterized Coons patch spanning a boundary composed of an arbitrary number of curves, we do calculations on it that are motivated by variational calculus that give a better optimized and possibly more smooth surface. A complete numerical implementation for a boundary composed of five straight lines is provided (that can model a string breaking) and get about 0.82 percent decrease of the area in this case as well. Given the demonstrated ability of our optimization algorithm to reduce area by as much as 37.9141 percent for a spanning surface not close to being a minimal x xi surface, this much smaller fractional decrease suggests that the Coons patch for f ive line boundary we have been able to write is also close to being a minimal surface. That is it is a near-minimal surface. This work compares the reduction in area for near-minimal surfaces (bilinear interpolation spanned by four boundary lines and a Coons patch whose boundary is rewritten for a boundary composed of five lines) with the surfaces whose minimal surfaces are already known (a hemiellipsoid spanned by an elliptic disc and a hump like surface spanned by four straight lines lying in the same plane) and we have been able to calculate numerically worked out differential geometry related quantities like the metric, unit normal, root mean square of mean curvature and root mean square of Gaussian curvature for the surface obtained through calculus of variations with reduced area.
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آئو وطن آباد کریں

آئو وطن آباد کر یں
نحمدہ ونصلی علی رسولہ الکریم امّا بعد فاعوذ بااللہ من الشیطن الرجیم
بسم اللہ الرحمن الرحیم
معزز اسا تذہ کرام اور میرے ہم مکتب ساتھیو!
آج مجھے جس موضوع پر اظہار خیال کرنا ہے وہ ہے:’’آؤوطن آباد کر یں‘‘
صدرِذی وقار!
وطن کی محبت ایمان سے ہے، وطن سے والہانہ عقیدت ایمان کا حصہ ہے، وطن ہے تو ہم ہیں ، وطن ہے تو ہمارا وجود قائم ہے، وطن کی خوشبو سے ہمارے دماغ معطر رہتے ہیں،وطن کے صحرودر یا ہمارا سرمایہ ہیں، وطن کے شجر وحجر ہمارا اثاثہ ہیں۔
محترم صدر!
اگر یہ الفاظ ہم دِل کی اتھاہ گہرائیوں سے کہتے ہیں، تو ہم قابلِ فخر ہیں، ہماری حیات کی ساعتیں قابلِ صد مبارکباد ہیں، ہمارے وطن کے بارے میں تصورات یقینا صائب ہیں، ہماری محبت واقعی وطن کے لیے حقیقی ہے، ہمارا خیال اپنی سرزمین کے لیے واقعی طلسماتی اور کرشماتی ہے۔
صدرِمحترم!
وطن سے محبت اور وطن کی آبادکاری دماغ کے سوچنے کانام ہیں، وطن کی تعمیر صرف زبان کے اظہار کا نام نہیں ،وطن کے گلشن کی تز ئین صرف جسم کی حرکات کا نام نہیں ، وطن سے محبت اور پیار صرف قول و قرار کانام نہیں۔
معزز سامعین!
وطن سے محبت کرنی ہے تو وطن کے افراد سے محبت کرنا ہوگی ، وطن کے در و دیوار سے محبت کرنا ہوگی ، وطن کے نقصان کو اپنا نقصان سمجھنا ہوگا ، وطن کے مفاد کو اپنے مفادات پر ترجیح دینا ہوگی ، وطن کی تعمیر میں لاثانی اور مثالی کردار ادا کرنا ہو گا کیوں کہ وطن ہی ہماری آن ہے، وطن سے ہماری شان ہے وطن ہے تو ہم ہیں وطن نہیں ہے تو ہم بھی نہیں ہیں کیونکہ یہی وطن ہی تو ہماری شناخت ہے۔
اقوام کے وجود...

اسلام اورہندومت میں احترام انسانیت ایک تقابلی جائزہ Respect for Humanity in Islam and Hinduism A Comparative Review

Every person in the world is respectable because he is a human being. All religions of the world have taught respect for humanity. It will not be wrong if we say that respect is the common heritage of humanity living in the world. Mutual respect is the secret and distinction of the development of nations. How many nations and cultures became enviable simply because they respected each other? In the present era, the dignity of humanity is being trampled everywhere. The murder market is hot everywhere. The standards of human respect are changing, sincerity, truth, human equality, and values ​​are being replaced by deceit, greed, envy, and selfishness. And it is done according to the resources. Man is the best of creation and legitimate respect and honor is his basic right. Therefore, no one can see his self-respect being undermined. That's why it has become very important to bring up topics like respect for humanity and explain the position and status of human beings in the light of religious books so that the respect and dignity of human beings are being trampled underfoot today, people should be made aware of the true status and status of human beings should be informed so that the importance of human blood can be estimated. An attempt will be made in this paper to present a comparative review regarding the respect and reverence that human has for Islam and Hinduism. Keywords: Respect for Humanity, Superior to all creatures, Religion, Islam, Hinduism, Respect, Self-respect

Biodiversity of Insects Associated With Rice Oryza Sativa L. Crop Agroecosystem in the Punjab, Pakistan

In this study, factors regarding the excessive use of pesticides and those particularly involved in the cultivation of high input and low input rice crop were investigated. Farmers’ sources of Basmati rice seed acquisition and perception of pest insects’ incidence and their management practices in rice crop were also evaluated. Results indicated that the main reason for farmers’ adoption of high input rice farming was to get better yields and profit. The main sources of rice seed acquisition were the home retained, local market and seed companies. Farmers were well aware of major pest insects of rice and reported moderate incidence of rice stem borers and high incidence of rice leaffolder but little was known about natural enemies and diseases. The most common reason for excessive use of insecticides was the misconception that pesticides were necessary to increase the yield. Farmers still relied to a great extent on chemicals to control the pests in rice crop and majority of them ignored economic threshold levels (ETL) recommended for the control. But the effective and economic suppression of insect pests in rice ecosystem by the judicial use of pesticides on the basis of ETL is utmost essential. Therefore, ETLs for the chemical control of rice stem borers (Scirpophaga incertulus Wlk. & S. innotata Wlk.) and rice leaffolder (Cnaphalocrosis medinalis Gn.) in the traditional Basmati rice growing area, the Kallar tract were also determined to be 5% dead-hearts (DH) and 3% folded leaves for stem borers and rice leaffolder respectively. The use of insecticides ignoring recommended ETLs along with higher doses of fertilizers is not only the cause of economic losses but also harmful to the insect biodiversity. So the effect of high inputs (HIP) farming practices on insect communities was also investigated. The higher number of species richness and abundance were measured for low input (LIP) systems. On the other hand some insects were abundant in HIP systems because of their adaptation to such kind of habitat. The insect species richness and abundance increased with rice crop age and showed close relationship with crop. All the major trophic guilds, except non rice pest (NRP), were also in abundance for LIP systems. Some species of insect were found sensitive to agrochemical pollution and were regarded as bioindicators. The higher Shannon’s value in some cases for HIP farms suggested that agrochemicals had a significant impact in eliminating the rare species and hence increased the Shannon’s and evenness values among the species. The overall effect of HIP rice farming on insect species richness and abundance was significantly negative. The LIP systems were found having greater diversity along with supporting a good number of rare species.