Entropy analysis of MHD flow of Jeffrey fluid in an inclined channel

This study is aimed at investigating the influence of entropy analysis of magnetohydrodynamic flow of Jeffrey fluid in an inclined micro-channel in the presence of thermal radiation and field suction/injection. We have improved the mathematical model of the physical problem under consideration. The designed equations have been solved by applying the shooting-based fourth-order, Runge–Kutta method with the boundary conditions, which describe velocity slip and temperature jump conditions at the fluid–wall inter-face. Numerical efforts are described graphically and mentioned quantitatively concerning different parameters such as Jeffery parameter, Bejan number, and entropy generation embedded in the problem. The numerical results for the expression of the irreversibility ratio are obtained. It is observed that the wall inclination strengthens the entropy production rate in the micro-channel, and the thermal buoyancy layer induces an increase in fluid velocity as suction.     

Combustion synthesis and properties of mullite-zirconia composites

Mullite-zirconia composite powders were prepared by the combustion of an aqueous heterogeneous redox mixture consisting of Al(NO₃)₃, Zr(NO₃)₄/ZrO(NO₃)₂, silica fume and urea/diformyl hydrazine at 500 °C. X-ray diffraction data showed that a large amount of tetragonal zirconia existed in the composite powders in spite of high temperature calcination. Milled composite powders showed enhanced densification compared to the unmilled powders and the microstructure of the sintered (1600 °C) compacts showed the presence of spherical zirconia grains in intergranular positions along with elongated mullite grains.     

Performance analysis of a dye-switched ruby laser under the step function Q-switch model

The performance of a dye-switched, 15 cm × 0.95 cm ruby laser, pumped by two linear flashlamps, in a polished, double elliptical cavity is reported. TheQ-switched output energy is examined under the step functionQ-switch model. It is noted that theQ-switched output energy shows a linear dependence on the flashlamp input energy, at variance with the step functionQ-switch theory, for a uniformly pumped laser. This anomaly is explained on the basis of non-uniform pumping. The energy ultilization factor using this theory is also reported.     

Mutual coupling compensation of linear antenna array using evolutionary optimization technique

This paper presents an optimization-based approach to compensate for the mutual coupling effect and to reduce the sidelobe level (SLL) of the normalized radiation pattern by optimizing the current excitation amplitude of the antenna array elements. Due to the mutual coupling effect, the SLL of the radiation pattern is increased, and thereby, the field pattern of the antenna array is severely degraded. This causes interference with other communication systems working at the same frequency. Toward the compensation of the mutual coupling effect and reduction of SLL, the Cat swarm optimization (CSO) algorithm is employed, and the excitation amplitudes of the antenna elements are optimized. In this regard, optimizing the cost function is defined by introducing the impedance factor (IF), calculated by using the self-impedance and mutual impedance of the antenna elements. The proposed method for the synthesis of a mutually coupled linear antenna array is less expensive, simpler to use, and more effective. Array sets of 4, 6, 8, and 10 elements are considered for optimization.     

Data Driven Approach for mmWave Channel Characteristics Prediction Using Deep Neural Network

Wireless Personal Communications - The elaborate architectures used in millimeter wave (mmWave) MIMO communication system make its channel characteristics prediction difficult. In this regard, we...     

An Enhanced Green Cloud Based Queue Management (GCQM) System to Optimize Energy Consumption in Mobile Edge Computing

Interference alignment (IA) adjusts signaling scheme such that all interfering signals are squeezed in interference subspace, and obtains the maximum degrees of freedom in an interference channel. However, IA mostly achieves its performance via infinite extension of the channel, which is a major challenge in practical systems. In this paper, we schedule part of interference to be strong and achieve perfect IA within limited number of channel extensions. A single-hop 3 user single antenna interference channel (IFC) is considered and it is shown that one of the interfering signal streams needs to be strong so that perfect IA is feasible. Practical implementation of the proposed scheme is discussed in detail for the case of two extensions of the 3 user single antenna IFC.

     

Geometry Aware Tori Decomposition

This work presents a shape decomposition algorithm to partition a complex high genus surface into simple primitives, each of which is a torus. First, using a novel iterative algorithm, handle and tunnel fundamental cycles on the surface are progressively localized. Then, the problem of computing the splitting cycles that produce such a tori decomposition is posed as a min‐cut problem on the mesh's dual graph with earlier computed tunnels as source and target. The edge weights for the min‐cut problem are designed for the cut to be geometry‐aware. We present an implementation and demonstrate the results of our algorithm on numerous examples.     

Computations of the acoustically induced phase shifts of optical paths in acoustophotonic imaging with photorefractive-based detection

Acoustophotonic imaging uses ultrasound-modulated scattered light to improve the quality of optical imaging in diffusive media. Experiments that use photorefractive-crystal-based detection have shown that there is a large dc shift in the acoustically modulated or ac optical signal, which could be utilized to further improve optical imaging resolution. We report that photon paths in a diffusive medium were generated by a Monte Carlo simulation, and the optical phase shifts of the various photons induced by the presence of a realistic focused ultrasound beam were calculated. Quantities that characterize the ac and dc signal components were evaluated by use of the calculated phase shifts. It was confirmed that the dc component dominates owing to coherent summation of the contributions from all the photons.     

Optimal array factor radiation pattern synthesis for linear antenna array using cat swarm optimization: validation by an electromagnetic simulator

In this paper, an optimal design of linear antenna arrays having microstrip patch antenna elements has been carried out. Cat swarm optimization (CSO) has been applied for the optimization of the control parameters of radiation pattern of an antenna array. The optimal radiation patterns of isotropic antenna elements are obtained by optimizing the current excitation weight of each element and the inter-element spacing. The antenna arrays of 12, 16, and 20 elements are taken as examples. The arrays are designed by using MATLAB computation and are validated through Computer Simulation Technology-Microwave Studio (CST-MWS). From the simulation results it is evident that CSO is able to yield the optimal design of linear antenna arrays of patch antenna elements.     

A low volume flexible CPW‐fed elliptical‐ring with split‐triangular patch dual‐band antenna

In this article, the intensive investigations are carried out on a low volume compact flexible antenna for wireless applications with a novel structure model. The proposed model has considered as an elliptical‐ring with split‐triangular patch (ERSTP) antenna with the coplanar waveguide feeding to achieve dual‐bands. The ERSTP antenna is designed with polyimide material having the volume (L _a × W _a × h) 99 mm³. The ERSTP antenna resonates with 2.60 GHz and 3.48 GHz frequencies with a reflection coefficient of ?21.92 dB and ?32.14 dB and a gain of 2.39 dBi and 1.75, dBi respectively. The impedance bandwidths are 100 MHz and 330 MHz observed at two frequency bands. The proposed ERSTP antenna has operated on mobile‐worldwide interoperability for microwave access (M‐WiMAX) and worldwide interoperability for microwave access (WiMAX) bands respectively. The simulated and measured results of ERSTP antenna are in good agreement.