Browsing by Author "Dr. Muhammad Asif"

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Study of Shafranov Shift by the Simplest Grad Shafranov Equation Solution for Various Tokamaks
(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2012) Kanwal Zulfiqar; FA10-MSPHY-005; Dr. Muhammad Asif; LHR TP 3515
Plasma internal energy is not conserved on a magnetic surface if nonlinear flows are considered. The Magnetohydrodynamic equilibrium in an axisymmetric plasma is described by the Grad Shafranov equation in terms of the magnetic flux. A generalized Grad Shafranov type equation has been used. Specific functional forms of plasma internal energy and current are used. A simplest analytic solution of the Grad Shafranov equation is used. This solution is over constrained both in shape and in plasma current. We demonstrate that the Shafranov shift for this solution is independent of plasma current for various tokamaks. We studied the dependence of Shafranov shift on various plasma parameters and found that Shafranov shift depends on parameters such as major radius, minor radius, aspect ratio and inverse aspect ratio. The Shafranov shift shows a direct relation with major radius „ ‟. The value of Shafranov shift increases with the increase in value of major radius. Similarly for minor radius „a‟ there exist a direct relation between Shafranov shift and minor radius. And inverse aspect ratio „a/ ‟ is also varies directly with Shafranov shift. For the case of aspect ratio Shafranov shift is inversely related to the aspect ratio „ ‟
Study of Shafranov Shift by the Simplest Grad Shafranov Equation Solution for Various Tokamaks
(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2012) Kanwal Zulfiqar; CIIT/FA10-MSPHY-005/LHR; Dr. Muhammad Asif; LHR TP 3515
Plasma internal energy is not conserved on a magnetic surface if nonlinear flows are considered. The Magnetohydrodynamic equilibrium in an axisymmetric plasma is described by the Grad Shafranov equation in terms of the magnetic flux. A generalized Grad Shafranov type equation has been used. Specific functional forms of plasma internal energy and current are used. A simplest analytic solution of the Grad Shafranov equation is used. This solution is over constrained both in shape and in plasma current. We demonstrate that the Shafranov shift for this solution is independent of plasma current for various tokamaks. We studied the dependence of Shafranov shift on various plasma parameters and found that Shafranov shift depends on parameters such as major radius, minor radius, aspect ratio and inverse aspect ratio. The Shafranov shift shows a direct relation with major radius „ ‟. The value of Shafranov shift increases with the increase in value of major radius. Similarly for minor radius „a‟ there exist a direct relation between Shafranov shift and minor radius. And inverse aspect ratio „a/ ‟ is also varies directly with Shafranov shift. For the case of aspect ratio Shafranov shift is inversely related to the aspect ratio „ ‟.
Synthesis and Simulation of Titanium Dioxide Nanomaterials
(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2021) Safdar Anjam; CIIT/FA19-RPH-028/LHR; Dr. Muhammad Asif; LHR TP 7675
In this work, the TiO2 nanostructures were synthesized by using the sol-gel method. The TiO2 has a wide bandgap, and its low work function makes it favorable as an electron transport layer for the application of perovskite solar cells (PSCs). During the synthesis of the TiO2 nanostructures, 7 ml of titanium tetra iso propoxide was used as a gel whereas the 60 ml isopropanol alcohol was used as a sol. TiO2 gel was obtained and dried at a temperature of 100ºC for 2 hours to make the powder form. Further, the TiO2 powder was dried via furnace for 3 hours at 550 oC to get the nanostructures of TiO2. A PSC is a kind of solar cell that includes a perovskite structured compound, most commonly a hybrid organic-inorganic lead or tin halide-based material, as the light-harvesting active layer. The active layer is sandwiched between a hole transport layer and an electron transport layer. Usually, a hole transport layer is a wide bandgap with high work-function material while the electron transport is a low work function and wide bandgap material. Even though perovskite solar cells' efficiency is as high as that of silicon solar cells, but the stability of the PSC is the main issue that needs to address for future enhancement of solar cells. In this project, we discussed various factors that influence the stability of PSCs.