Estimation of waste heat and its recovery potential from energy-intensive industries

Clean Technologies and Environmental Policy - The recovery and reuse of waste heat offers a significant opportunity for any country to reduce its overall primary energy usage. Reuse of waste heat...     

Magnetohydrodynamics in narrow fluidic channels in presence of spatially non-uniform magnetic fields: framework for combined magnetohydrodynamic and magnetophoretic particle transport

In this paper, we bring out the implications of a spatially varying magnetic field towards combined magnetohydrodynamic–magnetophoretic transport in narrow fluidic confinements. We first present a generic framework for describing the flow field that is generated under the combined influences of a driving pressure gradient, an axial electric field, and a spatially varying transverse magnetic field. As a demonstrative example, we derive analytical solutions for the flow field, based on a plausible choice of the mathematical form of the nature of spatial variation of the magnetic field. Proceeding further ahead, we also address the magnetophoretic motion of particles, subjected to such spatially varying magnetic fields. We depict the trajectories of representative spherical particles in the flow-field, as a combined consequence of the magnetohydrodynamic and magnetophoretic forcing mechanisms. We also demonstrate that such combined magnetophoretic and magnetohydrodynamic transport can be employed as a novel technique to separate particles based on sizes and electromagnetic properties.     

Compatibility of Lead-Bismuth Eutectic with SiC-Coated Graphite at Elevated Temperature

Uniform coating of β-silicon carbide (β-SiC) was formed over a graphite pellet through slurry-based silicon coating followed by in situ reaction at 1873 K (1600 °C). The coated pellet was exposed to molten lead-bismuth eutectic (LBE) at 1173 K (900 °C) in static condition for 200 h. Weight loss measurement, X-ray diffraction, and secondary electron microscopy–energy-dispersive spectroscopy confirmed that the SiC coating could effectively prevent molten LBE from attacking the inner graphite material.     

Semi-analytical solutions for electroosmotic flows with interfacial slip in microchannels of complex cross-sectional shapes

In this article, we investigate the implications of electroosmosis with interfacial slip on electrohydrodynamic transport in microchannels having complex (yet symmetric) cross-sectional shapes, by employing a generic semi-analytical approach. We also devise an approximate technique of flow rate prediction under these conditions, using a combined consideration of electroosmotic slip (under thin electrical double layer limits) and Navier slip conditions (originating out of confinement-induced hydrophobic interactions) at the fluid–solid interface. We further assess the effectiveness of the approximate solutions in perspective of the exact solutions, as a parametric function of the relative thickness of the electrical double layer with respect to the channel hydraulic diameter. We illustrate the underlying consequences through examples of elliptic, polygonal, point star-shaped, and annular microchannel cross sections.     

Dynamic economic dispatch using harmony search algorithm with modified differential mutation operator

Dynamic economic dispatch (DED), which is a complex non-linear constrained optimization problem, has a pivotal role in power system operation. It is one of the prime functions of power generation and control, where the aim is to operate an electrical power system most economically while the system operation is within its security limits. This problem possess non-convex characteristic when generation unit valve-point effects are considered. This paper proposes to solve DED problem with valve-point effects, using a modified form of recently developed differential harmony search algorithm. A five- and ten-unit system with non-smooth fuel cost function is used to establish the effectiveness of the proposed method over various other methods. It is shown that the proposed method is capable of providing better quality solutions.     

Brans-Dicke theory in anisotropic models with a viscous fluid

We consider anisotropic models of the Universe in the presence of a Brans-Dicke (BD) scalar field ϕ, a causal viscous fluid and a barotropic fluid. We show that, irrespective of the fluid, the causality theory provides a late-time acceleration of the Universe. If deceleration occurs in a radial direction and acceleration in the transverse direction, then the anisotropic Universe will accelerate for a particular condition in a power-law representation of the scale factors.     

Robust optimal control: low-error operation for the longest time

The problem of maximising the time during which an open-loop system can operate without exceeding a specified error bound is considered for linear systems that are subject to uncertainties about their parameters and their initial conditions, and whose operation is hampered by disturbance signals. The objective is to characterise an optimal input signal that keeps performance errors within specified bounds for the longest time. It is shown that such an input signal exists, and that it can be approximated by a bang-bang input signal without significantly affecting performance.