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Lahore, Pakistan

Jawad A.,COMSATS Institute of Information Technology | Butt S.,Lahore Leads University | Butt S.,Kinnaird College for Women | Rani S.,COMSATS Institute of Information Technology
European Physical Journal C | Year: 2016

Warm inflationary universe models in the context of the generalized Chaplygin gas, the modified Chaplygin gas, and the generalized cosmic Chaplygin gas are being studied. The dissipative coefficient of the form Γ ∝ T, and the weak and the strong dissipative regimes are being considered. We use the quartic potential, λ∗ϕ44, which is ruled out by current data in cold inflation but in our models by analysis it is seen to be in agreement with the WMAP9 and the latest Planck data. In these scenarios, the power spectrum, the spectral index, and the tensor-to-scalar ratio are being examined in the slow-roll approximation. We show the dependence of the tensor–scalar ratio r on the spectral index ns and observe that the range of the tensor–scalar ratio is r< 0.05 in the generalized Chaplygin gas, r< 0.15 in the modified Chaplygin gas, and r< 0.12 in the generalized cosmic Chaplygin gas models. Our results are in agreement with recent observational data like WMAP9 and the latest Planck data. © 2016, The Author(s).

Jawad A.,COMSATS Institute of Information Technology | Majeed A.,Lahore Leads University
Astrophysics and Space Science | Year: 2015

In this paper, we consider interacting pilgrim dark energy (Hubble horizon as an infrared cutoff) with cold dark matter in flat universe. We develop the equation of state parameter in this scenario which shows the consistency with pilgrim dark energy phenomenon. In this framework, we analyze the behavior of scalar field and corresponding scalar potentials (which describe the dynamics of the scalar fields) of various scalar field models, graphically. The dynamics of scalar fields and potentials indicate accelerated expansion of the universe which is consistent with the current observations. © 2015, Springer Science+Business Media Dordrecht.

Khan S.S.,College of Economy and Administration | Lodhi S.A.,Lahore Leads University | Akhtar F.,College of Economy and Administration | Khokar I.,College of Economy and Administration
Management of Environmental Quality | Year: 2014

Purpose: The purpose of this paper is to analyze the recent global situation on waste of electric and electronic equipment (WEEE) management and recommend policy directions for designing environmental strategies. Design/methodology/approach: Qualitative research approach is adopted to review studies on WEEE management in developed and developing countries. The focus is to critically consider the available options for its safe management. Findings: Approximately 40-50 million tons of WEEE is generated worldwide annually and most of it is dumped in the developing countries. WEEE is not a challenge to be faced by a single country as it has trans-boundary effects and ultimately the contamination reaches back to the developed countries with a lapse of time. Research limitations/implications: Data availability on WEEE generation and disposal is in initial stages. Practical implications: Developing countries in Asia and Africa do not have resources to handle WEEE. The unregulated and unsafe WEEE management practices in these countries let hazardous materials to disseminate into the marine life and global ecosystem. Originality/value: The paper recommends policy directions to deal with the emerging issue that may have globally far reaching consequences. © Emerald Group Publishing Limited.

Jawad A.,Lahore Leads University | Pasqua A.,University of Trieste
European Physical Journal Plus | Year: 2014

We study the reconstruction scenario of modified gravity with a dynamical dark-energy model filling the universe. In this context, we consider the Modified f(R) Horava-Lifshitz Gravity with a new agegraphic dark-energy model using the power-law form of the scale factor. We construct a modified f(R) Horava-Lifshitz model and check its behavior along its argument. To discuss the accelerated expansion of the universe, some cosmological parameters are discussed as well. The equation-of-state parameter represents the phantom behavior of the universe as well as the statefinder diagnostic pair gives the phantom and quintessence regions. Also, the stability analysis is carried out through squared speed of sound which points out the stable modified f(R) Horava-Lifshitz model except in a small time interval. © Società Italiana di Fisica/Springer-Verlag 2014.

Ene V.,Ovidius University | Ene V.,Simion Stoilow Institute of Mathematics of the Romanian Academy | Asloob Qureshi A.,Abdus Salam International Center For Theoretical Physics | Rauf A.,Lahore Leads University
Electronic Journal of Combinatorics | Year: 2013

Let L be a distributive lattice and R(L) the associated Hibi ring. We compute reg R(L) when L is a planar lattice and give bounds for reg R(L) when L is nonplanar, in terms of the combinatorial data of L. As a consequence, we characterize the distributive lattices L for which the associated Hibi ring has a linear resolution.

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