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Abstract In this work, we investigate the radial flow structure in gas–solids downer using Euler–Euler computational fluid dynamics (CFD) models. Solids are modeled as pseudo-fluid using kinetic theory of granular flow. In addition to the mass and momentum conservation equations, transport equation for fluctuating kinetic energy of the solids (modeled as granular temperature) is solved. The main focus of this work is the systematic investigation of the most suitable closures for the various force interactions in the system of interest. Results are presented for mean solids velocity, volume fraction, granular temperature and slip velocities for various closure forms. Sensitivity of the predicted results to the choice of closure forms is presented. Finally we emphasize the idea of matching slip velocities and the trends thereof with solids fraction as the key to developing a robust CFD model which has predictive capability over a wide variety of flow conditions.

This Paper presents a new approach for the optimal sizing and siting of substations and network routing problem. The solution approach proposed is a nolinear programming approach. The problem has been formulated as a Quadratic Mixed Integer programming (QMIP) problem in terms of the fixed costs of the substations and lines and the present worth of the energy loss costs of the line segments. The solution to this QMIP problem is obtained in two stages. In the first stage the quadratic programming problem is solved following the procedure developed by Wolfe using simplex method and treating all the variables as continuous variables. In the second stage, a procedure has been suggested to integerize the values of the integer variables. The proposed method is validated using a numerical example.

Abstract Particle shape characterization is playing an important role in many current processes and operations. Characterization techniques based on the behavior of particles in an apparatus offer a rapid, simple method for examining large particle samples and have the advantage that they can physically separate the sample into various shape fractions. Operating on the principle that settling velocity is influenced by shape, the continuous classifier or settler takes a closely sized sample of particles of the same density, and separates the sample into various shape fractions. Experimental results have demonstrated that the settler has satisfactory separation and recovery efficiencies and could be used for quality control of shape in an industrial environment.

In this study, the effects of discharge rate and LiMn2O4 cathode properties (thickness, porosity, particle size, and solid-state diffusivity and conductivity) on the gravimetric energy and power density of a lithium-ion battery cell are analyzed simultaneously using a cell-level model. Surrogate-based analysis tools are applied to simulation data to construct educed-order models, which are in turn used to perform global sensitivity analysis to compare the relative importance of cathode properties. Based on these results, the cell is then optimized for several distinct physical scenarios using gradient-based methods. The complementary nature of the gradient- and surrogate-based tools is demonstrated by establishing proper bounds and constraints with the surrogate model, and then obtaining accurate optimized solutions with the gradient-based optimizer. These optimal solutions enable the quantification of the tradeoffs between energy and power density, and the effect of optimizing the electrode thickness and porosity. In conjunction with known guidelines, the numerical optimization framework developed herein can be applied directly to cell and pack design.

Thin films of NiO have been prepared using potentiostatic electrodeposition technique from an aqueous electrolytic bath containing NiSO4. Deposited films have been characterized using x-ray diffraction, scanning electron microscopy and energy dispersive analysis by x-rays. X-ray diffraction patterns showed that the prepared films possess polycrystalline nature with face centered cubic structure. Surface morphology and film composition showed that films with better stoichiometry and smooth surface are obtained at optimized growth condition. Optical absorption analysis showed that the prepared films possess direct band gap value around 3.46 eV.

Abstract This study presents proposed Pseudo-Inspired Gravitational Search Algorithm (PI-GSA) for solving complex Economic Dispatch (ED) problem in the power system and Optimal sizing of the components for a self-contained and grid connected hybrid energy system that meets the load demand of a particular village. This method can be scaled according to the need of the system under investigation. From the results obtained, it can be inferred that with the use of local available energy sources, the grid connected mode serves as more economical and reliable choice for the electrification of numerous villages when compared with the stand-alone hybrid energy system. To check the effectiveness and performance of proposed algorithm simulation results for Complex Economic Dispatch (Cases 1) are compared with other methods reported in literature and Optimal sizing of the components for self-contained and grid integrated renewable energy resources (Case 2) are compared with the results obtained from Hybrid Optimization Model for Electric Renewable (HOMER). A qualitative comparison of the obtained result with other standard population based meta-heuristic techniques manifests proposed technique's superiority.

This article investigates the impact of manufacturing technology on the structure, mechanical, and tribological properties of new antifriction composite materials based on R6M5 high-speed tool steel grinding waste. The characteristics of the new composite’s structure formation and its impact on properties after use of the established technological modes, including grinding waste regeneration, were illustrated. It was demonstrated that such technology is capable of ensuring microheterogeneous structure. The material’s structure consists of the metal matrix based on R6M5 high-speed tool steel waste and uniformly distributed CaF2 solid lubricant in the steel matrix. As compared to known iron-based composites, this structure promotes a high degree of mechanical and tribological properties. During tribological tests, anti-seize thin films of 15–20 μm are formed on the contacting surfaces. These constantly renewable films contribute to the high antifriction properties of the composite under the studied friction conditions and provide a self-lubricating effect. Such films fully cover both the material’s surface and the counterface. The formation of antifriction films results in the self-lubrication mode. The findings of the study open up the possibility of predicting the friction behavior of a composite at high temperatures by selecting the initial metal grinding waste to ensure the appropriate level of properties. The extensive use of various alloy steel-based industrial grinding waste in the re-production cycle would significantly contribute to resolving the global environmental problem of protecting the environment from pollution.

Indian power sector is growing at an enormous pace. Building and operating such a power system is a challenging problem. The power network which carries the MWs across large distances is analogous to a "muscle system" of human body. Likewise, the entire range of associated monitoring and control network is analogous to a "nervous system". While strengthening the muscles is important in order to fully realize the potential, they also have to be complemented by an intelligent nervous system. This paper focuses on the intelligent grid aspects and the initiatives taken by the National Grid of India towards that direction. The participation of IBM - Indian Institute of Technology, Bombay (IITB) in the intelligent utility network (IUN) research is also mentioned.