Area-Delay and Energy-Efficient Throughput-Scalable VLSI Architecture for SDR Channelizer

A software-defined radio (SDR) channelizer extracts narrowband channels from the wideband signal. The impulse response of this filter is required to change with the desired channel to be extracted from the wideband input. A reconfigurable filter is used instead of fixed filters to implement the channelizer in a resource-constrained environment. In this paper, we present a throughput-scalable reconfigurable architecture for SDR channelizer. The proposed structure processes a block of L input samples and produces one block of L outputs in every clock cycle. The register complexity of the proposed structure is independent of throughput, whereas multiplier and adder complexity increases proportionately. A significant number of registers are saved when the proposed structure is implemented for larger filter-length and higher block-sizes. Theoretical estimates show that the proposed structure for the block-size 8 and filter-length 32 involves 256 extra multipliers and 105 extra adders against 6912 MUXes, 8 less registers than those of the existing similar structure, and it offers 8 times higher throughput. ASIC synthesis result shows that the proposed structure of block-size 8 and filter-length 32 involves 41 % less area-delay product and 22 % less energy per sample than those of the existing structure and offers nearly 6 times higher sampling rate than the other. At the normalized sampling rate, the proposed structure for filter-length 16 consumes 18 % and 22 % less power than the existing structure for block-sizes 4 and 8, respectively.     

Magnetohydrodynamic mixed convection flow in vertical concentric annuli with time periodic boundary condition: Steady periodic regime

This work reports an analytical solution for fully developed mixed convection flow of viscous, incompressible, electrically conducting fluid in vertical concentric annuli under the influence of a transverse magnetic field, where the outer surface of inner cylinder is heated sinusoidally and the inner surface of outer cylinder is kept at a constant temperature. The analysis is carried out for fully developed parallel flow and steady-periodic regime. The governing dimensionless momentum and energy equations are separated into steady and periodic parts and solved analytically. Closed form solutions are expressed in terms of modified Bessel function of first and second kind. The influence of each governing parameters such as magnetic field parameter, Prandtl number and the dimensionless frequency of heating on flow formation and thermal behaviour are discussed with the aid of graphs. During the course of investigation, it is found that the oscillation amplitude of the friction factor is maximized at a resonance frequency near the surface of the concentric annuli where there is periodic heating. Furthermore, increasing transverse magnetic field decreases the oscillation amplitude of the friction factor.     

Numerical solution for natural convection flow near a vertical porous plate having convective boundary condition with nonlinear thermal radiation

This article presents the theoretical study of the effects of suction/injection and nonlinear thermal radiation on boundary layer flow near a vertical porous plate. The importance of the convective boundary condition as regards the heat transfer rate is taken into account. The coupled nonlinear boundary layer equations are translated into a set of ordinary differential equations via a similarity transformation. The consequences of the active parameters like the suction parameter, injection parameter, convective heat transfer parameter, nonlinear thermal radiation parameters, and Grashof number dictating the flow transport are examined. The numerical result obtained shows that with suction/injection, the heat transfer rate could be increased with nonlinear thermal radiation parameter augment whereas decays with the convective heat transfer parameter and Grashof number. In the presence of suction/injection, the wall shear stress generally increases with nonlinear thermal radiation parameter, convective heat transfer parameter, and Grashof number. The suction has an increasing effect on Nusselt number and shear stress whereas a decreasing effect on Nusselt number and skin friction is seen with injection augment. The nonlinear thermal radiation is an increasing function of the temperature gradient far away from the plate whereas a decreasing function near the porous plate.     

First and second law investigation of waste heat based combined power and ejector-absorption refrigeration cycle

In the proposed cogeneration cycle, a LiBr-H₂O absorption refrigeration system is employed to the combined power and ejector refrigeration system which uses R141b as a working fluid. Estimates for irreversibilities of individual components of the cycle lead to possible measures for performance improvement. Results of exergy distribution of waste heat in the cycle show that around 53.6% of the total input exergy is destroyed due to irreversibilities in the components, 22.7% is available as a useful exergy output, and 23.7% is exhaust exergy lost to the environment, whereas energy distribution shows 44% is exhaust energy and 19.7% is useful energy output. Results also show that proposed cogeneration cycle yields much better thermal and exergy efficiencies than the previously investigated combined power and ejector cooling cycle. Current investigation clearly show that the second law analysis is quantitatively visualizes losses within a cycle and gives clear trends for optimization.     

Effects of hall current and wall temperature oscillation on free convective and mass transfer flow in a rotating porous medium with constant heat source

The combined effects of Hall current and a constant heat source on the hydromagnetic free convective and mass transfer flow past an infinite vertical porous plate in a rotating porous medium are considered, when the temperature of the plate varies with time about a nonzero constant mean and the temperature of the free stream is constant. The problem is solved analytically and the velocity profiles are shown on graphs. Effects of m (Hall parameter) and α (heat source parameter) on velocity are discussed extensively.     

MHD steady natural convection in a vertical porous channel in the presence of point/line heat source/sink: An exact solution

This study focuses on the steady free convection of an electrically conducting viscous and incompressible fluid in a vertically oriented porous channel with a line/point heat source/sink (point/line heat generation/absorption) at different channel positions in the coexistence of magnetic and suction/injection parameters. The constant heat source/sink parameters, which mathematically define the line heat source/sink, are modeled using the Heaviside step function. The Laplace transform procedure was applied to find the precise expression for the dimensionless governing equations that make up the flow model. Investigations were conducted on flow patterns with line graphs to visually depict the function of the magnetic, suction/injection, and heat generation parameters. The tabular simulations of results demonstrate that increasing the suction/injection parameter can result in a decrease in the mass flow rate by 8.9%. Similarly, increasing the magnetic parameter causes the mass flow rate to drop by almost 27%. Furthermore, with an improvement in the magnetic and suction/injection parameters, frictional force and mass flux values declined. An upsurge in the magnetic fieldand suction/injection parameters causes a rise in skin friction and mass flux near the left surface and a decline at around the right surface as the point heat source extends over a region.     

Influence of ramped pressure gradient on transient flow formation in a horizontal porous channel

The transient flow formation in a horizontal porous channel assuming a ramped pressure gradient is presented. The equation governing the flow is modeled into a partial differential equation (PDE) which is solved by employing the Laplace transformation technique to transform the PDE to an ordinary differential equation (ODE). The obtained ODE is solved by employing the method of undetermined coefficients to obtain the velocity profile in the Laplace domain. The Riemann sum approximation technique is then adopted to change the obtained solution from the Laplace domain into the time domain. For accuracy checks, the numerical results of the obtained equation are reckoned with previously published work, and an excellent agreement is found. For a clearer understanding of the impact of various flow parameters entering the solutions obtained, graphical and tabular representations are offered using MATLAB software. We noticed that the velocity is slower with ramped pressure gradient compared to a constant pressure gradient. This is because the motion of the fluid occurs gradually with ramped pressure gradient.     

Use of ade1 and ade2 mutations for development of a versatile red/white colour assay of amyloid‐induced oxidative stress in saccharomyces cerevisiae

Mutations in adenine biosynthesis pathway genes ADE1 and ADE2 have been conventionally used to score for prion [PSI⁺] in yeast. If ade1‐14 mutant allele is present, which contains a premature stop codon, [psi^?] yeast appear red on YPD medium owing to accumulation of a red intermediate compound in vacuoles. In [PSI⁺] yeast, partial inactivation of the translation termination factor, Sup35 protein, owing to its amyloid aggregation allows for read‐through of the ade1‐14 stop codon and the yeast appears white as the red intermediate pigment is not accumulated. The red colour development in ade1 and ade2 mutant yeast requires reduced‐glutathione, which helps in transport of the intermediate metabolite P‐ribosylaminoimidazole carboxylate into vacuoles, which develops the red colour. Here, we hypothesize that amyloid‐induced oxidative stress would deplete reduced‐glutathione levels and thus thwart the development of red colour in ade1 or ade2 yeast. Indeed, when we overexpressed amyloid‐forming human proteins TDP‐43, Aβ‐42 and Poly‐Gln‐103 and the yeast prion protein Rnq1, the otherwise red ade1 yeast yielded some white colonies. Further, the white colour eventually reverted back to red upon turning off the amyloid protein's expression. Also, the aggregate‐bearing yeast have increased oxidative stress and white phenotype yeast revert to red when grown on media with reducing agent. Furthermore, the red/white assay could also be emulated in ade2‐1, ade2Δ, and ade1Δ mutant yeast and also in an ade1‐14 mutant with erg6 gene deletion that increases cell‐wall permeability. This model would be useful tool for drug‐screening against general amyloid‐induced oxidative stress and toxicity. Copyright © 2016 John Wiley & Sons, Ltd.     

Return on capital and earned carbon credit by hybrid solar Photovoltaic—wind turbine generators

This paper presents a methodology to optimise a hybrid solar Photovoltaic—wind turbine generator for the villages situated in the remote areas, especially coastal regions of India. Owing to good insolation and wind density, the hybrid system composed of 6 photovoltaic (PV) modules, one wind turbine and 3 batteries are sufficient to fulfil all the necessary power demand without interruption for an Indian village. The analytical analysis shows that the system having lifespan of 30 years has return on capital, cost of power produced and cost of the hybrid solar-wind generators as 4.08%, € 0.155/kWh and € 4723.5/kWh respectively. The energy payback time is 2.47 years and will lead to earn € 28.52 every year of carbon credits.