Indian Institute of Technology Palakkad&nbsp;(IIT Palakkad or IIT PKD) is a public autonomous&nbsp;engineering&nbsp;and&nbsp;research&nbsp;institute located in&nbsp;Palakkad,&nbsp;Kerala. It was&nbsp;one of the five new&nbsp;IITs&nbsp;proposed in the&nbsp;2014 Union budget of India. The campus was inaugurated on 3 August 2015. The institute has 94 faculty, 978 students, and 63 non-teaching staffs.

IT Palakkad currently offers four-year Bachelor of Technology (B.Tech) and two years MS programmes in 8 different engineering disciplines including&nbsp;Computer Science, Electrical, Mechanical, Civil among others.

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IIT Palakkad

In the spirit of searching for Gd-based, frustrated, rare earth magnets, we have found antiferomagnetism (AF) in GdPtPb, which crystallizes in the ZrNiAl-type structure that has a distorted kagome lattice of Gd triangles. Single crystals were grown and investigated using structural, magnetic, transport, and thermodynamic measurements. GdPtPb orders antiferromagnetically at 15.5 K, arguably with a planar, noncollinear structure. The high temperature magnetic susceptibility data reveal an "anti-frustration" behavior having a frustration parameter, |f|=|Θ|/TN=0.25, which can be explained by mean field theory within a two-sublattice model. Study of the magnetic phase diagram down to T=1.8K reveals a change of magnetic structure through a metamagnetic transition at around 20 kOe and the disappearance of the AF ordering near 140 kOe. In total, our work indicates that GdPtPb can serve as an example of a planar, noncollinear AF with a distorted kagome magnetic sublattice. © 2017 American Physical Society.

Department of Physics

World University root node

Fulltext

Physical Review B

GdPtPb: A noncollinear antiferromagnet with distorted kagome lattice

BaSn2 has been shown to form as layers of buckled stanene intercalated by barium ions. However, despite an apparently straightforward synthesis and significant interest in stanene as a topological material, BaSn2 has been left largely unexplored, and has only recently been recognized as a potential topological insulator. Belonging to neither the lead nor bismuth chalcogenide families, it would represent a unique manifestation of the topological insulating phase. Here we present a detailed investigation of BaSn2, using both ab initio and experimental methods. First-principles calculations demonstrate that this overlooked material is indeed a strong, wide-gap topological insulator with a bulk band gap of 200 meV. We characterize the surface state dependence on termination chemistry, providing guidance for experimental efforts to measure and manipulate its topological properties. Additionally, through ab initio modeling and synthesis experiments, we explore the stability and accessibility of this phase, revealing a complicated phase diagram that indicates a challenging path to obtaining single crystals. © 2017 American Physical Society.

BaSn2: A wide-gap strong topological insulator

This paper presents a comprehensive study of the forward kinematic problem of a newly introduced spatial parallel manipulator, namely, the 3-RPRS manipulator. The manipulator has three legs with two actuators in each, which connect a moving triangular platform to a fixed base. Three loop-closure equations are formed with the three passive joint angles in the legs, as the unknowns, which are subsequently reduced to a single univariate polynomial equation of degree 16. The coefficients of this equation are obtained as closed-form functions of the architecture parameters of the manipulator and the input joint variables. Furthermore, it is found that the polynomial has only the even-powered terms, leading to 8 pairs of solutions. One solution in each pair represents a pose on one side of the fixed base, and the other, a reflection of the same at the said base plane. The theoretical developments are illustrated via several numerical examples, one of which yields 16 real solutions, thus establishing that the obtained univariate polynomial is minimal in its degree. The results obtained are validated numerically, as well as verified against the inverse kinematics of the manipulator, thereby establishing the correctness of the formulation as well as the results. © 2017 Elsevier Ltd

Department of Mechanical Engineering

Mechanism and Machine Theory

Forward kinematic analysis of the 3-RPRS parallel manipulator

GLOBAL CONFERENCE \& EXHIBITION– Vth Edition (flotek.g), FCRI Palakkad

Investigations on entrainment of surrounding fluid in jet flow in to a cylindrical tube nozzle

A unique hybrid Aerodynamic Shape Optimization (ASO) framework is devised for axisymmetric bodies with minimum drag coefficient in hypersonic inviscid flow at zero angle of attack. The hybrid ASO framework that has been developed in this paper makes use of a combination of low fidelity framework and high fidelity framework, with the intention to reduce the turn-around time from initial guess to final optimal solution with accurate estimation of cost function. This was achieved when low fidelity framework was able to generate near optimal solution with quick and reasonably accurate estimation of coefficient of drag (cost function for present study). The near optimal solution was then fed as the initial guess for high fidelity framework and it accelerated the convergence to global optimal solution. The low fidelity framework comprised of Modified Newtonian Theory as flow solver while ANSYS FLUENT (v 14.5) formed the flow solver for high fidelity framework. Optimization was effected using Steepest Decent in both the framework and Bezier curves were used for generic shape representation of bodies. ICEM-CFD was used to create the structured grid as required in Fluent. The result show significant reduction in computational cost from initial guess to final optimal solution. It was also observed that the optimal solution obtained from proposed multi-fidelity framework and optimal solution from CFD simulation only, are nearly comparable with marginal difference in the volume. The optimization also resulted in a reduction of coefficient of drag by more than 28%. © Springer India 2017.

Lecture Notes in Mechanical Engineering

A hybrid aerodynamic shape optimization approach for axisymmetric body in hypersonic flow

We propose an algorithm to solve thermobuoyant flows in the presence of magnetic field in enclosures with large temperature differences. The method is based on a staggered/non–staggered finite volume framework for incompressible flows which is modified to solve quasi-incompressible flows with heat transfer in the presence of applied magnetic field. The present framework is solves a single equation for normal momentum in the domain. This equation is discretized using a second–order convection scheme while central differencing is adopted for the viscous terms. An implicit solution approach which is first order accurate in time is employed and the resulting non–linear system of equations is solved using the Newton–Krylov approach. The momentum field at the cell centroids is then reconstructed using a defect–correction algorithm. The energy conservation equation is discretized similar to a collocated framework, with a first–order upwind scheme for the convective terms and implicit Euler time stepping. These equations are linearized by considering the velocity field at the latest available time step, and the resulting linear system of equations are solved using an ILU preconditioned GMRES solver using the LiS library. The approach is however still pressure–based with the energy equation employed to derive the divergence constraint to be used for solution of the pressure correction equation. Studies in enclosures over a range of temperature differences indicate that proposed approach can successfully simulate magneto-hydrodynamics convective flows with large density variation. © 2017, Begell House Inc. All Rights Reserved.

International Symposium on Advances in Computational Heat Transfer

Numerical investigation of high temperature gradient thermobuoyant flows with magnetic field

The study of dispersed laminar gas-particle flow in a horizontal channel is carried out using finite volume method on unstructured grid. In this context, Eulerian-Eulerian two-fluid model is employed to analyze the flow behaviour of both the phases inside the flow domain. The interaction between the gas phase and the particle phase is taken care by introducing the drag force term in their governing equations. The behavior of the particle phase when released at a low velocity into a uniform fluid flow is analyzed for particles having different sets of diameters. It has been found that for the particles of same material density, particle diameter plays an important role in the amount of drag force experienced by the particle phase dispersed in a continuous fluid medium. © Springer India 2017.

Eulerian-Eulerian modeling of dispersed laminar gas-particle flows over an unstructured grid

This paper proposes a vertical planar 2PRP-2PPR parallel manipulator along with a serial planar RRR passive orthosis (exoskeleton/supporting system) for performing sitting/lying type (stationary trainer) lower limb rehabilitation therapies in the sagittal plane. Proposed system's kinematic arrangement along with forward and inverse solutions is presented. System dynamics is derived to understand the behavior of the over-constrained manipulator-orthosis system. Further, a robust motion control scheme is proposed and the motion control scheme is based on non-singular fast terminal sliding mode control along with a nonlinear disturbance observer. The effectiveness and usefulness of the proposed manipulator is shown with the implementation of the motion controller through computer based numerical simulations using a clinical gait motion pattern. The proposed motion control scheme is also validated on an in-house fabricated prototype through motion control experiments. The controller parameter sensitivity and controller robustness are further analyzed at different working conditions. In comparison to the conventional controllers, the proposed control scheme possess few advantages namely better robustness, less chattering, high precision and fast finite time convergence, and can work in the presence of parameter uncertainties. From the demonstration, the proposed manipulator has certain advantages over existing stationary lower limb rehabilitation trainers namely, simple design, larger workspace, higher stiffness, modular design and low cost. © 2017 Elsevier Ltd

Design, development and control of a 2PRP-2PPR planar parallel manipulator for lower limb rehabilitation therapies

A meshfree framework for numerical simulations of magnetohydrodynamic flows is proposed. The framework is based on the Least-Squares-Based Upwind Finite Difference method (LSFD-U) and is capable of handling arbitrary point distributions. The approach is based on the least-squares method of error minimisation to compute the inviscid flux derivatives. The flux derivatives at every point require the fluxes at the point as well as those in fictitious interfaces in a neighbourhood around it. The fluxes at the fictitious interfaces are computed by using any numerical flux formula of interest that incorporates upwinding and consequently a global rather than the one-sided stencil may be chosen for computation. The meshfree framework is implemented through AUSM scheme, using a first-order accurate spatial and temporal discretisation. Studies on the one-dimensional MHD shock tube problems demonstrate the efficacy of the algorithm. The effect of non-uniform point distributions on the performance of the meshfree framework particularly with regard to conservation has also been studied. On the non-uniform grid the solutions of meshfree framework are not in agreement with the solutions of the finite volume framework unlike on uniform meshes. The finite volume formulation is known to be conservative and therefore it is very clear that meshfree formulation has conservation issues particularly as the grid becomes more non-uniform. It is therefore desirable to have a formulation for meshfree framework that preserves conservation at a discrete level like the finite volume method. Attempts have been made to develop a conservative meshfree framework using weighted least-squares technique for a particular case of one-dimensional non-uniform point distribution. © Springer India 2017.

A meshfree framework for ideal magnetohydrodynamics

We study the Wu metric on convex egg domains of the form where m &gt; 1/2, m ≠ 1. The Wu metric is shown to be real analytic everywhere except on a lower dimensional subvariety where it fails to be C2-smooth. Overall however, the Wu metric is shown to be continuous when m = 1/2 and even c1-smooth for each m &gt; 1/2, and in all cases, a non-Kähler Hermitian metric with its holomorphic curvature strongly negative in the sense of currents. This gives a natural answer to a conjecture of S. Kobayashi and H. Wu for such E2m.