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Stability Analysis of Celestial Objects and Cosmos

Thesis Info

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Author

Mumtaz, Saadia

Program

PhD

Institute

University of the Punjab

City

Lahore

Province

Punjab

Country

Pakistan

Thesis Completing Year

2017-07

Thesis Completion Status

Completed

Subject

Mathemaics

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/9228/1/Saadia_Mumtaz_Maths_2018_UoP_Punjab_19.07.2018.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727228150

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In this thesis, we study various evolutionary aspects of relativistic collapsing systems, thin-shell wormholes as well as cosmos by incorporating the e®ects of di®erent physical parameters. We consider both spherical and cylindrical stellar objects ¯lled with electromagnetic °uids and discuss their dynamical instability under radial oscillations. The dynamical instability of homogeneous sphere as well as relativistic polytropes is discussed by taking di®erent values of charge in Newtonian and post Newtonian regimes. Moreover, we evaluate the ranges of radii as well as adiabatic index for both charged and uncharged dissipative homogeneous cylinder. It is noted that dynamical instability occurs in the presence of charge if the gaseous mass contracts to the limiting radius. We discuss stability of thin-shell wormholes coupled with nonlinear electrodynam- ics in the vicinity of di®erent cosmological models for exotic matter. A general equa- tion of state is considered in the form of linear perturbation which explores stability of the respective wormhole solutions. We assume linear, logarithmic and Chaplygin gas models to study exotic matter at thin-shell and evaluate maximum viable regions for stability with di®erent values of the involved parameters. We also study stability of thin-shell wormholes in Einstein Ho®mann-Born-Infeld electrodynamics following the same dynamical approach. It is found that the Ho®mann-Born-Infeld parameter and electric charge enhance the stability regions. Finally, we discuss dynamical stability of isotropic and homogenous universe model via phase space analysis by taking a noninteracting mixture of electromagnetic and viscous radiating °uids whose viscous pressure satis¯es a nonlinear version of the Israel-Stewart transport equation. We evaluate corresponding critical points for var- ious choices of physical parameters. It is found that bulk viscosity as well as elec- tromagnetic ¯eld enhances the stability of accelerated expansion of the isotropic and homogeneous cosmos. We also study phase space analysis of locally rotationally sym- metric Bianchi type I universe model by taking di®erent linear combinations for the interactions between scalar ¯eld models and dark matter. This indicates a matter dominated epoch ultimately followed by a late accelerated expansion phase. We con- clude that all the critical points lead to accelerated expansion of the universe for tachyon coupled ¯eld.
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پھلاں دی کیاری

پھلاں دی کیاری
ملک حنیف دے کلام وچ درد ہجر ،فراق تے دکھاں دی کٹاری جگہ جگہ نظر اوندی اے۔جیویں کہ کتاب دا ناں ’’دکھاں دی پنڈ‘‘ رکھیا گیا اے۔دکھ ،دردتے قضیے سارے کلام وچ کھلرے پئے نے۔
تیرے ہجر دیاں میں سر تے

کنیاں بھاریاں پنڈاں چائیاں
جدائی دا ذکر وی کئی تھاواں تے بڑے سوہنے انداز نال پیش کیتا گیا اے
ہن محبوب کدی نہیں ملدے

پئی جدائی سالاں والی
محبوب دے ملن دی آس امید دے پھل تازے نیں،بڑے حوصلے نال آکھدے نیں۔
آخر سجن ملسی آ

کجھ دیہاڑے ہور وی تگ
حالات حاضرہ دی جھلک وی نظر اوندی اے تے پتا لگدا اے بھئی شاعر ماحول تے سیاست توں بے خبر نہیں۔
نویں پاکستان دا نعرہ

ویکھو تیل تے تیل دی دھار
مہنگائی توں عوام بڑی پریشان ایں تے غریب تے مزدور لوک بیچارے مہنگائی دے بارے ہی سوچاں سوچدے رہندے نیں۔
کیوں مہنگائی دا رونا روئیے کوسیے کیوں حکومت نوں
روٹی جے کر پکدی ہوے سوہنی پنج ست جیاں دی
مولی دھانے تے گنگلو گاجراں ایسیاں شیاں نے،جنہاں دی پنجاب دے وچ کوئی تھڑ نہیں۔سبزی ترکاری لیندیاں ہویاں چٹی سفید مولی تے ساوے کچوچ دھانے دوکاندار اینویں ہی ہتھ پھڑا دیندے سن تے ہن کی حال اے۔
مولی دھانے مہنگے ہو گئے

زور دیاں مہنگایاں ہویاں
پنجاب دی ثقافت دے جلوے وی نظر اوندے نے۔
پنڈاں اندر نہیں اے رونق ،رکھاںا تے شریہاں دی
لسی چاٹی والی مکھن ،نہیں خوشبو اے گھیاں دی
انج تاں ہر قسم دے موضوع اہناں دے کلام وچ ملدے نے،پر خاص طور تے درد وچھوڑا تے تصوف اے۔
ب بندوق چلا غماں دی آپ گیوں کتھ جائی اوئے
نین وکھا نشیلے کجلے اگ برہوں دی لائی اوئے
ہجر فراق تے وچھوڑے اندر...

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Agrarian Economy of the Bahawalpur State: 1866-1947

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