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Newtonian heating and convective boundary condition on MHD stagnation point flow past a stretching sheet with viscous dissipation and Joule heating

Sat, 01 Dec 2018 00:00:00 GMT

Title: Newtonian heating and convective boundary condition on MHD stagnation point flow past a stretching sheet with viscous dissipation and Joule heating Authors: Chaudhary, Santosh; Kanika, KM; Choudhary, Mohan Kumar Abstract: An analysis has been presented to study the effects of viscous dissipation and Joule heating on two-dimensional steady stagnation-point flow of an incompressible viscous electrically conducting fluid over a stretching plate with Newtonian heating and convective boundary condition in the presence of uniform transverse magnetic field. Similarity variables reduce the governing boundary layer partial differential equations to a set of non-linear ordinary differential equations and solved numerically using the Galerkin finite element method. Effects of various parameters such as stretching parameter, magnetic parameter, conjugate parameter, Prandtl number and Eckert number for velocity and temperature distributions have been discussed in detail through graphical representation. Moreover, numerical results of local skin-friction coefficient and local Nusselt number for different values of controlling parameters have been shown in tabular form and analyzed. Numerical values have been validated by comparing the present results with previously published works. Page(s): 931-940

Spectra of distorted quantum ring in external fields

Sat, 01 Dec 2018 00:00:00 GMT

Title: Spectra of distorted quantum ring in external fields Authors: Silotia, Poonam; Giri, Rajesh; Prasad, Vinod Abstract: The spectra and response of a single electron on a distorted quantum ring have been studied in detail. The distortion in the ring has been taken care by a geometrical factor. We take few different cases of distortion. Role of strength of the distortion along with the external static and laser field on spectrum has been studied. Page(s): 941-948

Design of log domain differential class AB universal biquad filter by employing lossy integrators

Sat, 01 Dec 2018 00:00:00 GMT

Title: Design of log domain differential class AB universal biquad filter by employing lossy integrators Authors: Duduk, Niyazi; Tola, Abdullah T Abstract: A new current mode low voltage differential Class AB second order universal biquad filter has been designed in this work. In design process, inspiring from Kerwin-Huelsman-Newcomb circuit, the circuit is realized with lossy integrators. The circuit has fundamental filter outputs namely; low pass, high pass and band pass. All pass and notch filter outputs have also been obtained by using additional circuits. In circuit design process, the state space method and translinear principle have been used. Two of the circuit parameters are electronically tunable which are the quality factor Q and the pole frequency f₀. PSpice circuit simulations have been obtained to check the theoretical results’ validity. In PSpice simulations, both ideal and AT&T CBIC-R type real transistor models have been used. Page(s): 949-958

A simple method to estimate the loading effects of Al/Si on the characteristic impedance of multilayer microstrip line

Sat, 01 Dec 2018 00:00:00 GMT

Title: A simple method to estimate the loading effects of Al/Si on the characteristic impedance of multilayer microstrip line Authors: Patel, Sandhya M; Kalra, Yogita; Ojha, V N; Sinha, R K Abstract: The present study aims to experimentally determine the microwave transmission and reflection properties of aluminum thin film grown on silicon using sputtering. A simple microstrip line based structure has been used for the microwave characterization in the frequency range 10 MHz to 26.5 GHz. Complex S-parameter measurements reveal only small differences on silicon loading and aluminum/silicon loading in comparison to the microstrip line. The characteristic impedance (Z) of the microstrip line loaded with silicon and with aluminum/silicon have been obtained corresponding to the length of the loadings using two port microwave analysis. Comparison of loaded microstrip line with no loading shows large changes in the real part well as imaginary part of the characteristic impedance in the frequency range less than 10 GHz. Percentage changes in the real (Z) and imaginary (Z) have been found as ± 40% and ± 10% in average, respectively, for silicon loading in comparison to the no loading case, whereas these changes have been found to be below ±5% for aluminium/silicon loading, thus these smaller changes suggest the similar responses for aluminium/silicon loading and no loading. The results reveal that the propagation can be restored with the application of aluminum with any semiconductor or dielectric as loading on the microstrip line, which shows its potential to be explored for making an individual microwave component. Page(s): 959-964