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

This paper addresses the dynamic control of a 2PRP-2PPR vertical planar parallel manipulator. This proposed manipulator can be used for the purpose of lower limb rehabilitation applications (in specific sitting/lying type of lower limb rehabilitation applications). The kinematic and dynamic model of the proposed manipulator are derived and discussed. An augmented PID control along with an uncertainty estimator is proposed for the motion control of the manipulator. The proposed system performance along with the motion controller is demonstrated numerically for the application of lower limb rehabilitation therapies using a clinically recorded gait data. The robustness of the controller and its parameter sensitivity are analysed through different operating conditions and their results are presented. Note: P—stands for Prismatic/translation joint and R—stands for Rotary/revolute joint. © Springer International Publishing AG 2017.

World University root node

Department of Mechanical Engineering

Mechanisms and Machine Science

Augmented PID control of a 2PPR-2PRP planar parallel manipulator for lower limb rehabilitation applications

The present work elucidates a comparative analysis to investigate the discrepancies between the incompressible and low Mach number approximations for numerically solving combined natural convection with radiative heat transfer in participating medium. The motivation behind the study is to quantify the physical differences concerning fluid flow and heat transfer characteristics between low Mach number and incompressible approximation and to examine the validity of the later for convective-radiative problems in an enclosure. A series of numerical experiments are performed considering natural convection with radiative heat transfer at large temperature difference in a square enclosure with a heated cylinder at its center using both approaches. The heated cylinder of three different geometric configurations viz circular, square and triangular shapes are considered in the present analysis to study the combined effects of various geometric form and influence of surface to surface along with gas radiation on flow and heat transfer characteristics in the cavity. Significant discrepancies are observed between the results of incompressible and low Mach number approximations, particularly for gas radiation, especially at high optical thickness. The local Nusselt number distribution also highlights the inaccuracies arising from the use of incompressible approximation demonstrating that it remains invalid for such scenarios. The results from the present low Mach number formulation are also found to be in good agreement with the compressible flow results of OpenFoam demonstrating the need for low-Mach number approximation in such scenarios. Entropy generation analysis shows that square geometry is the optimum design among the three geometries of heated cylinder as it has the maximum heat transfer and minimum entropy generation. © 2016 Elsevier Ltd

International Journal of Heat and Mass Transfer

Critical assessment of numerical algorithms for convective-radiative heat transfer in enclosures with different geometries

An efficient electrochemical sensor for selective detection of the neurotransmitter, epinephrine (Epn), has been fabricated with the aid of a functionalized multiwall carbon nanotube–chitosan biopolymer nanocomposite (Chit-fCNT) electrode. Multiwall carbon nanotubes (CNT) were successfully functionalized with the aid of nitric acid and confirmed by the Raman spectral data. Functionalized carbon nanotubes (fCNT) were dispersed in chitosan solution and the resulting bio-nanocomposite was used for the fabrication of sensor surface by drop and cast method. Electrochemical characteristics of the fabricated sensor were understood using cyclic, differential pulse voltammetry (CV, DPV) and electrochemical impedance analysis for the detection of Epn in phosphate buffer (pH 7.4). CV and impedance analysis revealed that the Chit-fCNT modified electrode enhances the electrodic reaction of Epn and facilitated the electron transfer more readily compared to that of bare electrode. Applying DPV for the detection of Epn, achieved 30 nM as the lowest detection limit in the determination range of 0.05–10 μM and the analytical time as low as 10 s. Selective determination of Epn against the coexistence of a number of biological electroactive interferents and reproducible results for the determination of Epn were demonstrated. The present biosensor has been found efficient for successful direct determination of Epn from pharmaceutical adrenaline formulations and urine samples. © 2017 Elsevier B.V.

Department of Chemistry

Materials Science and Engineering C

Carbon nanotube ensembled hybrid nanocomposite electrode for direct electrochemical detection of epinephrine in pharmaceutical tablets and urine

The workability and the densification behavior of a porous Al–B4C preforms have been carried out in the present investigation. Hot upsetting tests have been carried out on Al–B4C powder metallurgy (P/M) preforms having an initial preform density of 0.9 and having different B4C compositions of 2%, 4% and 6%. The samples were compressed between two flat dies in a hydraulic press of 50 ton capacity under varying deformation temperatures such as 200 °C, 300 °C, 400 °C and 500 °C under the tri–axial stress state condition. The workability and densification behavior of Al–B4C preforms were analyzed till the initiation of cracks on the outer surface of the preform. The experimental results were analyzed for the various deformation parameters such as axial strain, relative density, formability stress index and different stress ratio parameter under the tri–axial stress state condition. The formability and densification behavior were discussed with the axial strain (εz) during the hot upsetting process. The relationships between the various stress ratio parameters (σq/σeff σm/σeff) and formability stress index (βσ) as a function of the relative density under the tri–axial stress state condition were established. © 2017 The Society of Manufacturing Engineers

Journal of Manufacturing Processes

Hot workability and densification behavior of sintered powder metallurgy Al-B4C preforms during upsetting

When a stack consisting of layers of soft elastomer and thin metallic film is subjected to low intensity impact by releasing an axisymmetric spherical indenter from a vertical height, the foils buried within the stack undergoes large deformation and fracture. The shape of the deformed area nevertheless remains circular, its radius first increases with the depth from the surface of the stack and then decreases. In contrast, here we show that the symmetry of the deformed area breaks down when instead of a smooth elastomeric layer, one with topographical patterns is used in the stack. The metallic foil deforms through a polygonal area. The size and shape of the polygonal area vary with the flexibility of foil, geometry and dimension of the patterns and the intensity of the impact. For example, for one elastomeric layer decorated with pillars arranged in a square array, the damaged area turns rectangular to hexagonal and then to octagonal with increasing severity of impact, very much similar to polygonal wetting and spreading by a liquid on a patterned substrate. © 2016 Informa UK Limited, trading as Taylor & Francis Group.

Journal of Adhesion Science and Technology

Polygonal deformation of a metallic foil subjected to impact by an axisymmetric indenter

This review (with 121 references) gives a summary on recent advances in the use of nanomaterials for the optical determination of dopamine. It includes a brief overview of the clinical significance of dopamine followed by a discussion on the recent advances in various nanomaterial-based distinctive optical spectroscopic methods such as (a) colorimetry and spectrophotometry, (b) surface-enhanced Raman spectroscopy (SERS), (c) fluorescence spectrometry and (d) electrochemiluminescence (ECL) spectrometry. All sections are further divided into subsections based on the type of nanomaterial used and their advantages and disadvantages are discussed. A discussion on the validity of the nanomaterial-based optical detection of dopamine for human samples is also included. This review concludes with highlights of current challenges of nanomaterial-based optical sensors and an outlook on future perspectives. [Figure not available: see fulltext.]

Biological Sciences and Engineering

Microchimica Acta

Recent advances in optical detection of dopamine using nanomaterials

A Tröger's base-functionalised covalent organic polymer (TB-COP) was synthesised and used as an adsorbent for the efficient removal of picric acid (PA) from water through the use of weak and reversible supramolecular interactions such as hydrogen bonding and π-π interactions. TB-COP was readily synthesised in quantitative yield using a one-pot metal-free polymerisation reaction strategy between a semi-flexible aromatic triamine [L; benzene-1,3-5-tricarboxylic acid-tris-(4-amino-phenyl-amide)] and dimethoxymethane. The molecular structure, physicochemical and morphological characteristics of TB-COP were analysed by using various spectroscopic and imaging techniques. Thermogravimetric analysis showed TB-COP to be thermally stable up to 380 °C; while the calculated Brunauer-Emmett-Teller (BET) surface area was found to be 34 m2 g-1 at 273 K. The picric acid adsorption study of the activated TB-COP showed an excellent adsorption capacity of ca. 90% within 60 minutes of contact time at 298 K (Langmuir isotherm model: KL = 0.0541 ± 6 L mg-1, R2 = 0.9962); the adsorption efficiency being shown to improve with increasing temperature. The extraction of PA was also clearly visible to the naked eye, where the yellow colored PA solution became transparent upon addition of TB-COP. Other interfering phenolic organic pollutants showed poor to moderate adsorption efficiency. Importantly, TB-COP could be used to store PA over a long period of time in a safe manner, without any leakage or any significant loss in extraction efficiency. Moreover, the polymer could be reused for several adsorption cycles, as PA could be released back into the solution by simply changing the pH of the aqueous media. This makes TB-COP an extremely promising material for the selective and efficient removal of picric acid from water, and TB-COP can be considered as being a 'fast' and naked eye colorimetric indicator for such analytes. © 2017 The Royal Society of Chemistry.

Journal of Materials Chemistry A

Reversible adsorption and storage of secondary explosives from water using a Tröger's base-functionalised polymer

Encapsulation of dye molecules is used as a means to achieve charge separation across different dielectric environments. We analyze the absorption and emission spectra of several coumarin molecules that are encapsulated within an octa-acid dimer forming a molecular capsule. The water-solvated capsule effect on the coumarin's electronic structure and absorption spectra can be understood as due to an effective dielectric constant where the capsule partially shields electrostatically the dielectric solvent environment. Blue-shifted emission spectra are explained as resulting from a partial intermolecular charge transfer where the capsule is the acceptor, and which reduces the coumarin relaxation in the excited state. © 2017 American Chemical Society.

Journal of Physical Chemistry C

What is the Optoelectronic Effect of the Capsule on the Guest Molecule in Aqueous Host/Guest Complexes? A Combined Computational and Spectroscopic Perspective

Department of Electrical Engineering

Dead-Time Induced Oscillations in Voltage Source Inverter-Fed Induction Motor Drives

This paper proposes a novel configuration of six phase IM to drive from a three phase stacked multilevel inverter. Apart from greater fault tolerance compared to three phase, a six phase machine enables the use of low voltage devices for the inverter. Also the inverter used here is a three phase nine level stacked inverter which itself uses low voltage devices. Thus MOSFETs can be used for the inverter. The nine level inverter is formed by stacking 2 five level inverters each of which is developed by cascading an FC and a capacitor fed H-bridge. The inverter can be stacked further to obtain still higher number of voltage levels. This enables the use of batteries at the front end and still lower voltage devices which will significanly improve the efficiency. Hence this will find applications in electric vehicles because of the direct battery drive. Experiment is conducted on a 15 KW six phase IM by reconfiguring it as a three phase machine and driven by the three phase nine level stacked inverter using V/f control scheme. Detailed experimental results are provided to validate the concept.