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Evolution of the Universe and Dark Energy Mystery

Thesis Info

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Author

Jawad, Abdul

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/handle/123456789/1339

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676726148896

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We study the evolving universe in the presence of dark energy via different well-known cosmological parameters. Firstly, we consider interacting new holographic dark energy model with cold dark matter in non-flat FRW uni- verse. We obtain the equation of state parameter which represents the evo- lution of the universe from vacuum dark energy region towards quintessence region for particular values of the constant parameters. It is found that this model always remains unstable against small perturbations. The correspon- dence of this model with quintessence, tachyon, k-essence and dilaton scalar field models is also established. The dynamics of scalar fields and potentials provide consistent behavior with the accelerated expansion of the universe. We also consider interacting generalized holographic dark energy with cold dark matter in non-flat universe. We find that the deceleration parameter lies in the accelerated expansion phase of the universe and the equation of state parameter provides quintom like nature. This dark energy model is stable against small perturbations for specific range of constant parame- ters. It is found that the quintessence and tachyon potentials correspond to scaling solutions. Secondly, the pilgrim dark energy phenomenon is explored by choosing three cutoffs such as Hubble as well as event horizon and conformal age of the universe in flat universe. We study the pilgrim dark energy which plays an effective role on the equation of state parameter for exploring phantom region of the universe. The freezing region is found in the ω Λ − ω Λ plane and the ΛCDM is achieved in the statefinders plane for all three models of pilgrim dark energy. The conjecture of pilgrim dark energy is also studied by xixii assuming the apparent and event horizons in non-flat universe and develop ω Λ − ω Λ as well as r − s plane. It is interesting to mention here that the pilgrim dark energy with event horizon yields phantom region for all cases of d 2 with u < 0. For these models, ω Λ − ω Λ plane provides the thawing as well as freezing region and ΛCDM limit. The r − s plane shows the correspondence with different models such as quintessence and phantom dark energy, ΛCDM and chaplygin gas. Also, we investigate the validity of the generalized second law of thermodynamics with event horizon in flat as well as non-flat universe. Finally, we consider the modified holographic dark energy interacting with cold dark matter with varying G in flat and non-flat Kaluza-Klein universes. For this dark energy model, we assume event horizon as an infrared cutoff scale. We discuss the equation of state parameter and check the validity of the generalized second law of thermodynamics. In non-flat Kaluza-Klein case, we investigate the s−r plane in which the corresponding curves meet the limit of ΛCDM model .
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مولانا اخترا حسن اصلا حی

مولانا اختراحسن اصلاحی
افسوس ہے کہ گزشتہ مہینہ مولانا اختر احسن صاحب اصلاحی مہتمم مدرسۃ الاصلاح سرائمیر نے انتقال کیا، وہ مولانا حمیدالدین فراہیؒ کے ارشد تلامذہ میں تھے، ان کو انھوں نے اپنی مخصوص طرز پر کلام مجید پر غور و فکر اور اس کی تفسیر و تاویل کی تعلیم دی تھی اور وہ اس کے اچھے شارح و ترجمان تھے، اور سیاست میں بھی پوری دستگاہ حاصل تھی، دینداری اور زہد میں بھی استاد بزرگ کے شاگرد رشید تھے، انھوں نے پوری زندگی نہایت سادگی اور قناعت کے ساتھ ایک قلیل معاوضہ پر مدرسۃ الاصلاح کی خدمت میں گذار دی، اس زمانہ میں غربت و عسرت کے ساتھ علم و دین کی خدمت صرف عربی مدارس کا حصہ ہے وہ طبعاً نیک نفس، خاموش، عزت پسند اور نام و نمود سے بے نیاز تھے، ورنہ ان کے بعض رفقاء کی طرح ان کا شمار بھی مشاہیر میں ہوتا، مدرسۃ الاصلاح کی روح رواں اب وہی تھے، وفات کے وقت پچپن سال کے قریب عمر رہی ہوگی، اﷲ تعالیٰ علم و دین کے اس خادم کو اپنی رحمت و مغفرت سے سرفراز فرمائے۔ (شاہ معین الدین ندوی، نومبر ۱۹۵۸ء)

 

Association of Serum Ferritin with Risk of Anemia in Non-Diabetic Adolescents with Family History of Type 2 Diabetes Mellitus

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Teachers Perceptions of Quality and Quality Management Systems at Higher Education Level in Pakistan.

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