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

is paper addresses a task-space trajectory control of an underwater vehicle-manipulator system (UVMS) employed for interactive underwater tasks. .e robust task-space tracking control is achieved by designing a non-singular fast terminal sliding mode controller (NFTSMC) with disturbance estimator and demonstrated on a planar underwater vehicle with serial two link manipulator arm a.ached to it. .e proposed NFTSMC integrates a non-singular fast terminal sliding mode controller (NFTSMC) with a non-linear disturbance observer. This combination not only assures €nite and faster convergence of the systems states to the equilibrium from anywhere in the phase-plane but also overcomes the problem of singularity associated with conventional terminal sliding mode controller (TSMC). In addition to this, because of the disturbance observer augmented in the proposed control law, the overall stability of the closed-loop system is enhanced to a great extent. .e feasibility of the proposed NFTSMC is con€rmed by performing extensive numerical simulation on the UVMS for tracking a given pre-de€ned task space trajectory under the in.uence of parameter uncertainties, ocean current and measurement sensor noises.

World University root node

Department of Mechanical Engineering

ACM International Conference Proceeding Series

Robust non-singular fast terminal sliding mode task-space position tracking control of an underwater vehicle-manipulator system

In the present work, the development of a general purpose, indigenous computational fluid dynamics code, ANUPRAVAHA, has been described for simulations of three-dimensional multi-physics problems. The code solves the governing fluid flow and heat transfer equations in a collocated, cell-centered, finite-volume framework, independent of the grid topology. The equations are discretised and solved in an implicit segregated manner using a fractional step approach. The momentum equations cast in a conservative form are linearized using Picard linearization and solved for auxiliary momenta at the cell centers. A new gradient reconstruction approach which is consistent and interpolation-free using a compact stencil is also employed for centroidal gradient computations. Time accurate simulations for unsteady problems are guaranteed using a three-point backward differencing scheme which gives second-order temporal accuracy. Governing equations for scalar quantities such as temperature (energy), concentration (species), volume fraction and turbulence quantities (such as kinetic energy and specific dissipation) are cast in a conservative transport form and discretised akin to the momentum equations. Several two-equation models using eddy-viscosity hypothesis have been implemented for turbulent flows. The pressure is then obtained by solving a Poisson equation obtained by enforcing the divergence condition. A novel generic momentum interpolation approach is applied to ensure proper pressure-velocity coupling, in the presence of large body forces and singular interfacial forces even on hybrid grids. While the solver is primarily devised to handle incompressible flows, the methodology has also been extended to weakly compressible flows, typical of non-Boussinesq convection and radiation, using a low Mach number formulation (Paolucci [1982]). The developed solver has been validated for simulating various multi-physics problems like conjugate heat transfer; droplet rising, falling and splashing; radiative heat transfer problems coupled with fluid flow and turbulent flows along with heat transfer. © 2017, Begell House Inc. All Rights Reserved.

International Symposium on Advances in Computational Heat Transfer

Lessons from anupravaha: Towards a general purpose computational framework on hybrid unstructured meshes for multi-physics applications

Cryogenic machining is a sustainable manufacturing approach; it eliminates coolant disposal cost, health problems compared to the conventional flood cooling. The present study investigates the multiple response optimisation of turning process while machining AISI 17-4 PH stainless steel under the cryogenic environment (jetting of liquid nitrogen at -196°C at the rake face of the tool) by using Taguchi-based grey relational analysis. The optimum levels of the machining parameters are cutting speed at 120.89 m/min, feed rate at 0.048 mm/rev, depth of cut 0.4 mm and physical vapour deposition (PVD) AlTiN coated tungsten carbide (WC). Taguchi-based grey relational analysis method reduced the cutting forces by 7.75%, improved the surface finish by 55.87%, and increased the material removal rate (MRR) by 154.76% and 25% increased the tool flank wear in cryogenic turning process. From the analysis of variance, it was identified that feed rate is the most influenced process parameter on turning performance characteristics. Copyright © 2017 Inderscience Enterprises Ltd.

International Journal of Machining and Machinability of Materials

Multi-objective optimisation of cryogenic turning process using Taguchi-based grey relational analysis

The present work investigates an experimental study of thermally enhanced machining of nickel-based superalloy Inconel 718 using uncoated tungsten carbide inserts. An inexpensive flame heating technique using an oxyacetylene flame is used as a heat source for thermal enhancement of workpiece. The effects of cutting parameters like cutting speed, feed rate, depth of cut and temperature of workpiece on the performance characteristics like surface roughness, tool wear and material removal rate were studied. A L27 orthogonal array with four parameters and three levels was adopted for experimental design. Multi response optimisation was done using grey relation analysis to simultaneously minimise surface roughness, tool wear and to maximise material removal rate. It was observed that at cutting speed at 85.21 m/min, feed rate at 0.048 m/min, depth of cut at 0.6 mm and workpiece temperature at 600°C were optimal cutting parameters. It is clearly shown that the above performance characteristics in thermally enhanced machining can be improved effectively through this approach. Copyright © 2017 Inderscience Enterprises Ltd.

Multi objective optimisation of thermally enhanced machining parameters of Inconel 718 using grey relational analysis

The Thirring model with random couplings is a translationally invariant generalisation of the SYK model to 1+1 dimensions, which is tractable in the large N limit. We compute its two point function, at large distances, for any strength of the random coupling. For a given realisation, the couplings contain both irrelevant and relevant marginal operators, but statistically, in the large N limit, the random couplings are overall always marginally irrelevant, in sharp distinction to the usual Thirring model. We show the leading term to the β function in conformal perturbation theory, which is quadratic in the couplings, vanishes, while its usually subleading cubic term matches our RG flow. © 2017, The Author(s).

Department of Physics

Fulltext

Journal of High Energy Physics

Comments on the random Thirring model

We describe general features of thermal correlation functions in quantum systems, with specific focus on the fluctuation-dissipation type relations implied by the KMS condition. These end up relating correlation functions with different time ordering and thus should naturally be viewed in the larger context of out-of-time-ordered (OTO) observables. In particular, eschewing the standard formulation of KMS relations where thermal periodicity is combined with time-reversal to stay within the purview of Schwinger-Keldysh functional integrals, we show that there is a natural way to phrase them directly in terms of OTO correlators. We use these observations to construct a natural causal basis for thermal n-point functions in terms of fully nested commutators. We provide several general results which can be inferred from cyclic orbits of permutations, and exemplify the abstract results using a quantum oscillator as an explicit example. © 2017, The Author(s).

Thermal out-of-time-order correlators, KMS relations, and spectral functions

Biological Sciences and Engineering

Haematologica

Demystification of enigma on antigen-presenting cell features of human basophils: Data from secondary lymphoid organs

We previously identified the chemokine receptor CCR4 as part of the molecular signature of melanoma brain metastasis. The aim of this study was to determine the functional significance of CCR4 in melanoma brain metastasis. We show that CCR4 is more highly expressed by brain metastasizing melanoma cells than by local cutaneous cells from the same melanoma. Moreover, we found that the expression of CCR4 is significantly higher in paired clinical specimens of melanoma metastases than in samples of primary tumors from the same patients. Notably, the expression of the CCR4 ligands, Ccl22 and Ccl17 is upregulated at the earliest stages of brain metastasis, and precedes the infiltration of melanoma cells to the brain. In-vitro, CCL17 induced migration and transendothelial migration of melanoma cells. Functionally, human melanoma cells over-expressing CCR4 were more tumorigenic and produced a higher load of spontaneous brain micrometastasis than control cells. Blocking CCR4 with a small molecule CCR4 antagonist in-vivo, reduced the tumorigenicity and micrometastasis formation of melanoma cells. Taken together, these findings implicate CCR4 as a driver of melanoma brain metastasis. © Klein et al.

Oncotarget

CCR4 is a determinant of melanoma brain metastasis

We report magnetization, heat capacity, Li7 nuclear magnetic resonance (NMR), and muon-spin rotation (μSR) measurements on the honeycomb 4d5 spin liquid candidate Li2RhO3. The magnetization in small magnetic fields provides evidence of the partial spin-freezing of a small fraction of Rh4+ moments at 6 K, whereas the Curie-Weiss behavior above 100 K suggests a pseudo-spin-1/2 paramagnet with a moment of about 2.2μB. The magnetic specific heat (Cm) exhibits no field dependence and demonstrates the absence of long-range magnetic order down to 0.35 K. Cm/T passes through a broad maximum at about 10 K and CmT2 at low temperatures. Measurements of the spin-lattice relaxation rate (1/T1) reveal a gapless slowing-down of spin fluctuations upon cooling with 1/T1∼T2.2. The results from NMR and μSR are consistent with a scenario in which a minority of Rh4+ moments are in a short-range correlated frozen state and coexist with a majority of moments in a liquid-like state that continue to fluctuate at low temperatures. © 2017 American Physical Society.