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

Deep neural network (DNN)-based methods are suitable for the rapid inversion of borehole resistivity measurements. They approximate the forward and the inverse problem offline during the training phase, and they only require a fraction of a second for the online evaluation (aka prediction). Herein, we have adopted a DNN-based iterative algorithm to design a borehole instrument such that the inverse solution is unique for a given earth parameterization. We select a large set of electromagnetic measurement systems routinely used in logging operations, and our DNN algorithm selects a subset of measurements that are suitable for inversion purposes. Numerical results with synthetic data confirm that this approach can provide valuable insight when designing borehole-logging instruments. © 2022 Society of Exploration Geophysicists.

World University root node

Department of Mechanical Engineering

Geophysics

A deep learning approach to design a borehole instrument for geosteering

B0-VPG graphs are intersection graphs of axis-parallel line segments in the plane. Cohen et al. (Order 33(1), 39–49, 2016) pose the question of characterizing B0-VPG permutation graphs. We respond here by characterizing B0-VPG cocomparability graphs. This helps us show that a simple necessary condition in fact characterizes B0-VPG permutation graphs. The characterization also leads to a polynomial time recognition algorithm and its proof gives us a B0-VPG drawing algorithm for the class of B0-VPG cocomparability graphs. Our drawing algorithm starts by fixing any one of the many posets P whose cocomparability graph is the input graph G. On the set of axis-parallel line segments in the plane, we define a binary relation “≺2” as p ≺2q if and only if they are non-intersecting and the bottom-left endpoint of p precedes the top-right endpoint of q in the product order on ℝ2. The reflexive closure ≼2 of the relation ≺2 restricted to the line segments of our drawing turns out to be a partial order isomorphic to the poset P. © 2021, The Author(s), under exclusive licence to Springer Nature B.V.

Department of Computer Science and Engineering

Order

Characterization of B0-VPG Cocomparability Graphs and a 2D Visualization of their Posets

arXiv preprint arXiv:2201.

Eternal vertex cover number of maximal outerplanar graphs

Six-degree-of-freedom (6-DOF) hovering control is important for underwater robots to perform various tasks. Our previous underwater robot study, which used tilting thrusters, could not control 6-DOF motion simultaneously owing to several mechanical and control problems. In this study, we developed a new robot with tilting thrusters and improved 6-DOF hovering performance. The maneuverability of the robot was evaluated by analyzing the force and moment of the thrust vector. Based on this, a redundant tilting mechanism without constraints was designed to solve structural problems. A proportional–integral–derivative (PID)-based control design using the decomposition and compensation method (PID-DC) that is appropriate for this mechanism, was derived. The decomposition method was used to overcome the nonlinearity of the thrust vector caused by the tilting mechanism, and the null-space projection technique was applied to minimize the thrust force and avoid the boundary of the tilting angle. A compensator based on the empirical model of the tilting thruster transferred the control input to the system with regulation. Simulation and experimental results verified the validity of the controller for the 6-DOF hovering motion of the robot, and the hovering performance was significantly improved. Furthermore, the stability of the hovering performance under tidal currents was demonstrated through disturbance experiments. © 2021 Elsevier B.V.

Robotics and Autonomous Systems

Hovering control of an underwater robot with tilting thrusters using the decomposition and compensation method based on a redundant actuation model

We investigate temporal cooperative behaviour in a realistic model of a molecular motor-cargo assembly by simulating a one-dimensional stochastic model of a motor-bound bead in an optical trap. Here, each motor is linked to a bead through an elastic spring, and performs forward and backward hopping motions on the filament. The rates characterising the forward and backward steps are different because of the free energy change associated with ATP hydrolysis. Apart from forward and backward hopping, motor bind to, and unbind from the filament with specific rates, while remaining attached to the bead. The bead is subjected to elastic force originating from the stretched motor-springs, thermal noise as well as an external force from an optical trap. We constructed a Gillespie code which can simulate the dynamics of up to six motors. Our results indicate that the emergence of cooperative behaviour, as observed in experiments, is closely connected with the load-sharing properties of the team. Simulation results of the mean first passage time show excellent agreement with experimental data of the same in the literature. © 2022, Indian Association for the Cultivation of Science.

Department of Physics

Indian Journal of Physics

Temporal cooperativity of a group of elastically coupled motor proteins stalled in an optical trap

We revisit the Partially-Saturated-Cells method (PSC) in the context of incompressible single-phase flows past stationary and moving bodies. This methodology adds a solid collision operator to the Lattice Boltzmann Equation, resulting in a unified evolution equation everywhere in the domain that suitably accounts for the boundary conditions. The unified evolution equation, which also allows for a smooth transition from solid cells to fluid cells, is dictated by the solid volume fraction, obtained using a simple geometric approach. We prove that the PSC approach exhibits nominal second-order accuracy in presence of straight and curved boundaries for pressure, although spatial order of accuracy in velocity degrades to first-order. Our analysis also reveals that PSC is approximately discretely conservative in the incompressible limit with the mass conservation errors being dependent on the lattice size and relaxation time. For simulations involving moving body problems, the method is found to introduce acceptable level of spurious force oscillations, which rapidly decrease with increasing grid resolution. To the best of the authors' knowledge, the present investigations pertaining to discrete conservation and spurious force oscillations in the PSC approach have never been discussed in literature. Extensive numerical experiments are performed involving both stationary and moving bodies, with imposed and induced motion, to assess the applicability of the PSC approach. Our findings illustrate that the inclusion of added mass effects are important for accurate force and torque computations in case of accelerating solids. Numerical investigations, that include unsteady flows featuring three degrees-of-freedom fluid-particle interactions clearly highlight the ability of the PSC approach in resolving complex hydrodynamical phenomena. This in-depth evaluation of the PSC approach conclusively demonstrates its efficacy as a promising computational framework for efficient and robust computations of incompressible fluid flows over a range of flow scenarios. © 2022 Elsevier Ltd

Computers \& Mathematics with Applications

Re-examining the partially saturated-cells method for incompressible flows with stationary and moving bodies

13th Innovations in Theoretical Computer Science Conference (ITCS 2022)

Bounded Indistinguishability for Simple Sources

A novel and simple stochastic meshfree method is proposed in the present study for the stochastic eigenvalue analysis of problems in structural mechanics. Young's modulus is modelled as homogeneous random field. Both truncated normal and lognormal distribution characteristics are used. The current work proposes to use Monte Carlo simulation (MCS) on a modified system of equations. Here, the stochastic stiffness matrix is approximated using Taylor series expansion as in perturbation methods. However, the method does not make any approximations for eigensolutions, which are also unknown functions of random variables. This enables the numerical integration of stiffness matrix and its derivatives outside the simulation loop. Unlike the direct MCS on system of equations, this simple but previously unexplored modification proposed, can result in accurate and more efficient evaluation of stochastic eigensolutions. A few numerical examples are solved using the proposed method; buckling of columns, buckling of thin plates and free vibration of beams. The probabilistic characteristics evaluated using the proposed method are found to be matching well with those obtained from direct MCS. © 2022 Elsevier Ltd

Department of Civil Engineering

Probabilistic Engineering Mechanics

A simple and efficient stochastic meshfree method for linear eigenvalue problems in structural mechanics

Abstract: Deformation until the beginning of disintegration (i.e., the first rupture time) is the first stage of a droplet’s secondary breakup in a gas stream. Experiments were performed to examine the effects of density, viscosity and surface tension of the liquid on the droplet deformation characteristics. The characteristics include droplet relative velocity, displacement and deformation. The test liquids included molten metals along with water-like liquids, offering wide ranges of density (788–6900 kg/m3), viscosity (0.86–3.63 mPa s) and surface tension (0.022–0.71 N/m). Results are presented in terms of non-dimensional numbers corresponding to each liquid property: density ratio, viscosity ratio and surface tension ratio. It was observed that the density and surface tension ratios affected the deformation aspects, but the effect of the viscosity ratio was not significant. For the liquids excluding the metals, the relative velocity of the droplet’s leeward side was significantly smaller compared to that of the windward side, at the first rupture time. The relative velocity of the droplet was observed to be higher for the liquid with higher density ratio. At low Weber numbers (We< ∼ 20), lower deformation was observed for the metals compared to other liquids. For We< ∼ 40 , higher first rupture times of low-surface-tension-ratio liquids contribute significantly to their higher displacements. Thus, it is concluded that, in addition to the Weber number, the density and surface tension ratios may need to be separately considered to characterize the droplet’s deformation phase. Graphic Abstract: [Figure not available: see fulltext.] © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.

Experiments in Fluids

Droplet deformation during secondary breakup: role of liquid properties

Wire electrical discharge machining (wire-EDM) process is having immense potential over conventional machining methods due to its non-contact nature of material removal. However, frequent and unanticipated machining failures like wire breakages negatively affect the productivity, sustainability and efficiency of the process. In this context, there is a wide scope to improve the process efficiency through online condition monitoring. A prominent aspect of EDM condition monitoring is discharge pulse discrimination. The threshold based methods which are currently being used has low accuracy and is reliant on operator's experience. In this study, a machine learning (ML) based pulse classification based on the extracted discharge characteristics is proposed. The features are extracted from the raw voltage and current senor signals collected from the machining zone during the wire EDM operation. Among the various ML models, Artificial Neural Network (ANN) classifier is found to have the maximum prediction accuracy of 98 %. Also, the effects of different discharge pulses on the productivity, surface finish and machining failures are investigated. The short circuit and arc discharges are found to cause wire breakage failure if they predominate the pulse cycle by more than 80 %. Also, short and arc sparks increase the surface roughness significantly, by up to 70 %. © 2022 IEEE.