Browse Articles

    Volume 2, Issue 1, Jan 2016

    Indicatrix as a pair of planes and right circular cylinder for three dimensional Finsler Space
    P.D. Mishra, M.K. Mishra
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      • Abstract: In this paper, we consider two cases of three-dimensional Finsler Space, namely, indicatrix at any point as a pair of planes, and a right circular cylinder. We also use the notion of density at any point in the space. We then obtain fundamental function in each case and show that any geodesic in three-dimensional Finsler Space where indicatrix at any point is right circular cylinder is logarithmic spiral.

    Effect of Alkanes on interfacial tension of Fish Oil-AgNO3 and on flow patterns in PFA mini-channel
    S. Kirubanandan
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      • Abstract: The multiphase flow with reaction and mixing of the extraction process at mini/micro scale continues to be an area of active research. In mini/micro-fluidic systems, the surface forces increase until gravitational forces no longer have a significant impact on the hydrodynamics of the system. Interfacial tension (IFT) forces begin to play a more predominant role in determining flow patterns due to the reduction of channel diameter. The flow pattern strongly depends on the physical properties of fluids and dimension of the channel. Recently, the flow of Fish oil-AgNO3 in PFA mini-fluidic channel is stratified and attempted to bring slug flow pattern by addition of alkanes. In order to tune flow pattern, the various proportions of alkanes were added into this binary system and then evaluated IFT for Fish Oil EE–Water, Fish Oil EE–Silver nitrate Solution and Hexane-Fish Oil EE-Silver nitrate at 25°C using Spinning drop tensiometry. The Eotvos number and flow transition map between capillary number and Froude number for these experimental fluids are evaluated and commented the dominating forces for flow transition from stratification to slug flow. The addition of alkanes into the fish oil phase does elevate the interfacial tension significantly and then the slug flow pattern was anticipated in mini-channel. But the flow visualization investigations confirmed that the stratification of flow was observed even addition of alkanes into the fish oil phase. The reason for stratification would be the reduction of interfacial tension at the interface and reversible chemical reaction between fish oil ethyl ester and silver nitrate solution .

    Numerical study of gas dynamics equation arising in shock fronts
    M. Tamsir, O. Acan, J. Kumar, A.K. Singh
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      • Abstract: In this paper, numerical solution of gas dynamics equation arising in shock fronts is obtained by using a modified cubic B-spline differential quadrature method (MCB-DQM). Present method is used in space to obtain a system of first-order ordinary differential equations which is solved by an optimal five stage fourth-order strong stability preserving Runge-Kutta scheme (SSP-RK54) in time. Two numerical examples of gas dynamics equations with known exact solutions are carried out. Obtained results are compared with the exact solutions and a good agreement is found.

    Stability analysis and internal heating effects on oscillatory convection in a viscoelastic fluid layer under gravity modulation
    B.S. Bhadauria, A. Singh, M.K. Singh, B.K. Singh
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      • Abstract: In this paper, we study the combined effect of internal heating and time periodic gravity modulation on thermal instability in a viscoelastic fluid layer, using complex non-autonomous Ginzburg-Landau equation. The influence of relaxation and retardation time of viscoelastic fluid on heat transfer has been discussed. A weak non-linear stability analysis has been performed by using power series expansion in terms of the amplitude of gravity modulation, which is assumed to be small. The Nusselt number has been obtained in terms of the amplitude for oscillatory mode of convection. It is found that modulation has a destabilizing effect at low frequencies and stabilizing effect at high frequencies. Further, it is also found that overstability advances the onset of convection more with internal heating, hence increases heat transfer. We have also studied the subcritical Hopf bifurcation and pitchfork bifurcation. The phase portrait diagrams are also shown for these bifurcations.

    Analytic and numeric computation of two dimensional unsteady nonlinear coupled viscous generalized Burgers’ equation
    V.K. Srivastava, M. Tamsir, M.M. Rashidi
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      • Abstract: In this paper, we derive a general analytical solution of the two dimensional coupled unsteady nonlinear generalized burgers’ equations via Hopf-Cole transformation and separation of variable method, which is used to generate three different sets of initial and boundary conditions. These sets of conditions are used for numerical approximations of the Burgers’ equations using the described implicit Logarithmic finite-difference method on the uniform mesh point. The effect of the variation in the Reynolds number is investigated and the accuracy of the scheme is determined through error norms. The described scheme is stable for the small time step and high Reynolds number.

    Performance of Thin Film Transistor: A Review
    S.K. Dargar, J.K. Srivastava
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      • Abstract: Transparent electronics becomes one of the most advanced topics for wide range of device applications. The key components are wide band gap semiconductors, where oxides of different origins play an important role as passive component and also as active component, similar to what is observed in conventional semiconductors like silicon. Transparent electronics has gained special attention during the last few years and is today established as one of the most promising technologies for leading the next generation of flat panel display due to its excellent electronic performance. In this paper the recent progress in n-type oxide based thin-film transistors (TFT) is reviewed. After a short introduction where the main advantages of these semiconductors are presented, as well as the industry expectations, the beautiful history of TFTs is revisited. Then, an overview is presented of TCAD simulation tool for TFT.