Department of Mechanical Engineering

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

Membrane curvature of a biological cell is actively involved in various fundamental cell biological functions. It has been discovered that membrane curvature and binding of peripheral membrane proteins follow a symbiotic relationship. The exact mechanism behind this interplay of protein binding and membrane curvature has not yet been properly understood. To improve understanding of the mechanism, we study curvature sorting of proteins in a model system consisting of a tether pulled from a giant unilamellar vesicle using mechanical-thermodynamic models. The concentration of proteins bound to the membrane changes significantly due to curvature. This has also been observed in experiments by other researchers. We also find that there is a phase transition based on protein concentration and we discuss the coexistence of phases and stability of solutions. Furthermore, when sorting is favorable, the increase in protein concentration stabilizes the tether in the sense that less pulling force is required to maintain the tether. A similar mechanism may be in place, when motor proteins pull tethers from donor membranes. © 2012 American Physical Society.

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Physical Review E - Statistical, Nonlinear, and Soft Matter Physics

Curvature sorting of proteins on a cylindrical lipid membrane tether connected to a reservoir

This paper presents a tracking control scheme for an autonomous underwater-manipulator system (UVMS) where the proposed null space controller is not only used to track the given desired path but also allows the use of the self-motion of the vehicle to perform power efficient trajectory because of its kinematically redundant nature. In the proposed scheme, the primary task is to track the given end-effector task space trajectory despite of external disturbances, system uncertainties and internal noises. As the energy savings requirement, the vehicle motion is controlled to be aligned with the estimated ocean current orientation. The performance and effectiveness of the proposed coordinated control motion of the UVMS is demonstrated numerically and confirmed with the specified planar UVMS tasks. © 2012 IEEE.

Program Book - OCEANS 2012 MTS/IEEE Yeosu: The Living Ocean and Coast - Diversity of Resources and Sustainable Activities

A null space control of an underactuated underwater vehicle-manipulator system under ocean currents

This paper presents a new task space tracking control scheme for an underactuated underwater vehicle. The effectiveness and robustness of the proposed control scheme are demonstrated and discussed via numerical simulations. Simulation results show that the thruster configuration of the existing vehicle consisting of three control inputs is sufficient for controlling the underactuated underwater vehicle to track any given desired spatial task space trajectories. Copyright © 2012 IEEE.

2012 9th International Conference on Ubiquitous Robots and Ambient Intelligence, URAI 2012

A nonlinear task space tracking control of an underactuated underwater vehicle

In this paper, coupled response measurements are suggested for detection of a transverse surface crack in a cantilever beam. The crack has been modelled by a local compliance matrix of six degrees of freedom and simulated for detection. The eigenfrequencies are obtained using finite element method (FEM) and are compared with those of experiments. However, the small changes in eigenfrequencies are not enough for crack detection. The flexibility matrix contains non-diagonal terms, and thus indicating the coupling among the different modes of vibrations. A harmonic force of known amplitude and frequency is used to dynamically excite the beam in bending mode. But due to the presence of crack, the bending excitation induced the axial and torsional vibrations also. The measurements of direct (bending) response and coupled (axial and torsional) responses are carried out using triaxial accelerometer and rotational laser vibrometer (RLV). The experiments are carried out for different bending frequencies, crack depths and locations. The results indicate that the coupled responses are very sensitive to crack; hence these measurements are suggested for crack detection. © 2012 Inderscience Enterprises Ltd.

International Journal of Structural Engineering

Crack identification in a cantilever beam using rotational laser vibrometer-based coupled of bending, axial and torsional vibrations

Liquid atomization is a problem with applications in many fields. In the present study, an air-assisted impinging jet atomizer has been utilised and its spray characteristics have been studied at various conditions, using water as the liquid and nitrogen as the atomizing gas. Two configurations were studied: one having a central gas jet above two impinging liquid jets and another having a central liquid jet targeted by two inclined gas jets. Backlit imaging and particle/droplet imaging and analysis techniques were utilised to characterise the sprays. It was observed that the configuration with a central gas jet and impinging liquid jets resulted in better atomization that the other case. It was observed that both the breakup length of the sheet and the resulting droplet sizes, reduced with an increase in the gas flow rate. The diameter of the gas jet orifice was also found to play an important role in changing the spread of the spray, the droplet sizes and the radial distribution of droplet sizes. Overall, it is observed that by varying the gas-to-liquid ratio and nozzle orifices, it is possible to obtain a fine atomization of the spray using the air-assisted impinging jet configuration even at low injection pressures of below 0.4 MPa. © ICLASS 2012 - 12th Inte. Con. on Liquid Atom. and Spray Systems. All rights reserved.

International Conference on Liquid Atomization and Sprays, ICLASS

Experimental spray characterisation of air-assisted impinging jets

Computational Fluid Dynamics simulations are performed to study mixture preparation in the intake manifold of a small engine with Port Fuel Injection. Data from laser-based experiments on two injectors are used as inputs to the spray sub-model. The results reveal improved in-cylinder fuel distribution when the spray is directed onto the intake valve. The Sauter Mean Diameter of the spray is observed to have an insignificant effect during open valve injection, while the targeting is found to have a large influence. The methodology developed as part of this work can be used to further optimize injection parameters in such engines. Copyright © 2012 Inderscience Enterprises Ltd.

Progress in Computational Fluid Dynamics

Modelling of mixture preparation in a small engine with port fuel injection

Addition of membrane in the form of vesicles is essential for the cytokinesis of animal and plant cells. In the animal cell cytokinesis, membrane fusion acts along with the contraction of an actomyosin ring to separate the cytoplasmic contents. In this study, the possible driving mechanisms for the membrane addition to the plasma membrane of the dividing animal cell and their consequences are presented. Taking cues from earlier studies, we propose that the membrane addition to the plasma membrane in the form of vesicles can be governed by the lateral tension present in the plasma membrane or, the concentrations of actin and myosin proteins at the cleavage furrow or, both simultaneously. The study attempts to elucidate the relationship between membrane addition and the force exerted by the contractile ring. The predictions from our study agree qualitatively with the experimental studies in which the vesicle fusion or the acto-myosin assembly were blocked during cytokinesis. However, the precise role of the two above mentioned mechanisms may depend on various parameters including but not limited to the cell type, organism and microenvironment around the dividing cell. © 2012 Elsevier Ltd.

Journal of Theoretical Biology

Role of membrane addition in animal cell cytokinesis

The curvature of biological membranes is controlled by membrane-bound proteins. For example, during endocytosis, the sorting of membrane components, vesicle budding, and fission from the plasma membrane are mediated by adaptor and accessory proteins. Endophilin is a peripherally binding membrane protein that functions as an endocytic accessory protein. Endophilin's membrane tubulation capacity is well known. However, to understand the thermodynamic and mechanical aspects of endophilin function, experimental measurements need to be compared to quantitative theoretical models. We present measurements of curvature sorting and curvature generation of the endophilin A1 N-BAR domain on tubular membranes pulled from giant unilamellar vesicles. At low concentration, endophilin functions primarily as a membrane curvature sensor; at high concentrations, it also generates curvature. We determine the spontaneous curvature induced by endophilin and observe sigmoidal curvature/composition coupling isotherms that saturate at high membrane tensions and protein solution concentrations. The observation of saturation is supported by a strong dependence of lateral diffusion coefficients on protein density on the tether membrane. We develop a nonlinear curvature/composition coupling model that captures our experimental observations. Our model predicts a curvature-induced phase transition among two states with varying protein density and membrane curvature. This transition could act as a switch during endocytosis. © 2012 Biophysical Society.

Biophysical Journal

Nonlinear sorting, curvature generation, and crowding of endophilin N-BAR on tubular membranes

An attempt was made to characterize the dry microelectric discharge machining (μ-EDM) plasma systematically by using optical emission spectroscopy. In order to characterize the plasma and its parameters such as plasma temperature, electron density, Debye length, and gamma parameter, the optical spectra were recorded for different energies and with different diameters of tool electrode. From the recorded spectra, using line pair method and modified Saha equation, plasma temperature and electron density, respectively were calculated. From these two, Debye length and plasma parameter were also calculated. These studies indicate that the plasma produced in dry μ-EDM is ideal. In addition to this, we found that the dry μ-EDM region is below the conventional EDM region in log electron density and log temperature plot. Morphological analysis was carried out on crater produced by different energies on the workpiece using a scanning electron microscope. The crater shape may dependent on the geometry of the tool tip, number of discharges, and energy of discharge. © 2011 Springer-Verlag London Limited.

International Journal of Advanced Manufacturing Technology

Plasma characterization of dry μ-EDM

Research investigating lipid membrane curvature generation and sensing is a rapidly developing frontier in membrane physical chemistry and biophysics. The fast recent progress is based on the discovery of a plethora of proteins involved in coupling membrane shape to cellular membrane function, the design of new quantitative experimental techniques to study aspects of membrane curvature, and the development of analytical theories and simulation techniques that allow a mechanistic interpretation of quantitative measurements. The present review first provides an overview of important classes of membrane proteins for which function is coupled to membrane curvature. We then survey several mechanisms that are assumed to underlie membrane curvature sensing and generation. Finally, we discuss relatively simple thermodynamic/mechanical models that allow quantitative interpretation of experimental observations. © 2011 by Annual Reviews. All rights reserved.