Indian Institute of Technology Kharagpur

About: Indian Institute of Technology Kharagpur is a education organization based out in Kharagpur, India. It is known for research contribution in the topics: Natural rubber & Dielectric. The organization has 16887 authors who have published 38658 publications receiving 714526 citations.

Small scale effect on the buckling analysis of single-layered graphene sheet embedded in an elastic medium based on nonlocal plate theory

Abstract: Nonlocal elasticity theory is implemented to investigate the buckling behavior of single-layered graphene sheet (SLGS) embedded in an elastic medium. Nonlocal elasticity theory accounts for the small-size effects when dealing with nanostructures such as graphene sheets. Both Winkler-type and Pasternak-type foundation models are employed to simulate the interaction between the graphene sheet and the surrounding elastic medium. Based on principle of virtual work, governing differential equations for the aforementioned problem are derived. Differential quadrature method is being employed and numerical solutions for the buckling loads of SLGS are obtained. Numerical results show that the buckling loads of SLGS are strongly dependent on the small scale coefficients and the stiffness of the surrounding elastic medium. With elastic medium modeled as Winkler-type foundation, the nonlocal effects are found to have decrease–increase–decrease pattern with increase in stiffness of elastic medium.

Stochastic assembly line balancing using simulated annealing

Abstract: The problem of balancing assembly lines with stochastic task processing times is addressed. The size of the problems that can be solved by optimal methods is limited and hence many heuristics have been developed, which give sub-optimal solutions. An approach for solving the problem using the simulated annealing technique is presented here. The proposed approach tries to reach the global optimum by not getting trapped at the different local optimum points. Another feature of this method is the non-dependence of the final solution on the initial solution. Solutions for line balancing problems obtained using the above method compare favourably with the results of other greedy heuristics.

Application of magnetic energy storage unit as load-frequency stabilizer

Abstract: Fast-acting energy storage devices can effectively damp electromechanical oscillations in a power system because they provide storage capacity in addition to the kinetic energy of the generator rotor, which can share the sudden changes in power requirement. The effectiveness of small-sized magnetic energy storage (MES) units (both superconducting and normal loss types) for this application is shown, and means of best utilizing the small energy storage capacity of such units to improve the load-frequency dynamics of large power areas are suggested. The proposed method of improving the load frequency control of power systems has the advantage that it does not require the governor or any other part of the power system to perform any sophisticated control action. The control logic suggested for this purpose takes the area control error as its input and uses inductor current deviation feedback. In a power system with a SMES (superconducting MES) unit, the optimal setting of the integrator gain is altered to a higher value. With the suggested control measure, SMES units of 4-6 MJ capacity would suffice in reducing the maximum deviations of frequency and tie-line power flow by about 40% in power areas of 1000-2000 MW capacity. >

On the parameters to assess the glass forming ability of liquids

Abstract: A new parameter has been proposed to assess the glass forming ability of liquids and its effectiveness is compared with the existing parameters. The new parameter ( α = T x / T l ), which incorporates both the factors of stability of the liquid (a low T l ) and the thermal stability of glass (a high T x ), has good correlation with the critical cooling rate for glass formation in a wide variety of glass forming alloys. This parameter can even be used for those glass forming alloys, which do not show a clear glass transition temperature. It has also been shown that the heating rate used during differential scanning calorimetry has negligible effect on the different glass forming parameters.