Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Department of Physics

Membranes of poly(vinyl alcohol) (PVA), gum arabic (GA) homopolymer and their blends of six different compositions (w/w) were prepared using solution casting method. Mixing of synthetic polymer e.g., PVA and natural polymer e.g., gum arabic can give a new class of polymer blend with better mechanical properties and biocompatibility than those of single components. The structural, optical and conductivity studies of these prepared membranes were examined by XRD, FTIR, UV and EIS. The XRD diffraction patterns for the polymer blend samples showed that they are more amorphous in nature as compared to pure PVA and pure gum arabic. The FTIR analysis of the samples gave information about various functional groups present in the samples. The energy band gap of various samples were obtained from UV-visible analysis. The conductivity of polymer membrane was analyzed by electronics impedance spectroscopy (EIS). Addition of natural polymer gum arabic has resulted slight increase in the conductivity of blend polymer.

VIT Unitversity

World University root node

School of Advanced Sciences

Vellore Campus

Fulltext

Asian Journal of Chemistry

Synthesis and Characterization of Polyvinyl Alcohol-Gum Arabic Polymer Blend Membranes

Here we report the fabrication of a novel three-dimensional conjugated porous polymer (CPP–P1) developed by a palladium-catalysed Sonogashira poly-condensation reaction. The solid polymer was thoroughly characterized by 13C cross-polarization solid-state NMR and X-ray photoelectron spectroscopy (XPS). The pristine nitrogen-containing CPP was explored as an electrocatalyst for the oxygen reduction reaction (ORR) in alkaline media 0.1 M KOH. We observed that in the case of pristine polymer CPP-P1 oxygen reduction occurs through four electron transfer pathway with excellent stability and good tolerance to methanol. The detailed molecular-level structure for oxygen reduction and mode of oxygen binding site to the polymer was explained by density functional theory (DFT) calculation. © 2019 Elsevier Ltd

Dyes and Pigments

Redox active nitrogen-containing conjugated porous polymer: An organic heterogeneous electrocatalysts for oxygen reduction reaction

In this article, we demonstrate the synthesis of single phase Bi1-xSrxFe1-yCoyO3 (x = y = 0, x = 0.02; y = 0.01, 0.03, 0.05, 0.07) using a facile sol-gel route. The powder X-ray diffraction measurements of all the samples confirm the pure phase rhombohedral structure with a small lattice distortion. The morphological analysis demonstrated decrease in average particle size from ~ 64 to 41 nm with increasing Co doping in Bi0.98Sr0.02Fe1-yCoyO3 due to slower growth rate. Mössbauer study reveals the change in oxidation state of iron (Fe3+ → Fe2+) at higher doping concentration of Co. Further, the successful co-doping of Sr, Co into BiFeO3 lattice remarkably enhances the saturation magnetization value from 0.8 emu/g to 2.3 emu/g and remnant magnetization from 0.08 emu/g to 0.532 emu/g. The enhanced magnetic properties of Sr, Co co-doped BiFeO3 nanoparticles is ascribed to the breaking of cycloidal spin structure, more number of uncompensated spin on the surface, and oxygen vacancies. Moreover, these samples were found to be highly efficient for the degradation of Rhodamin B (RhB) dye under visible light irradiation. The best RhB degradation activity was observed with 7% Co doping Bi0.98Sr0.02Fe1-yCoyO3 (BSFCO7) due to its lower bandgap, reduced average particle size and larger specific surface area. © 2019 Elsevier B.V.

Applied Surface Science

Facile single phase synthesis of Sr, Co co-doped BiFeO3 nanoparticles for boosting photocatalytic and magnetic properties

The titanium alloy Ti-6Al-4V was subjected to laser peening (without coating) at power densities of 3, 6 and 9 GW cm−2. The cross sectional profiles of microhardness and residual stress indicated softening in the bulk (away from the surface) at power density of 9 GW cm−2. This behavior was analyzed using a combination of Zerilli-Armstrong phenomenological model in conjunction with the concept of adiabatic heating. The implications of this analysis was supported by structural changes in terms of α → β transition (analyzed through synchrotron radiation) and microstructural changes in terms of primary α (equiaxed) to secondary α (lamellar) transformation, which is observed for the first time here. Based on this, optimum levels of peening to improve fatigue lives are suggested through relevant experiments. © 2019 Elsevier Ltd

Optics & Laser Technology

Mechanical properties of a laser peened Ti-6Al-4V

Pseudocapacitance generally appears due to the surface or near-surface reversible Faradaic reactions. In this regard, 2D layered materials have gained substantial attention as a potential source for driving a myriad of energy storage applications owing to their unique surface-structure relationship. Here, we have demonstrated that a pseudocapacitive mechanism becomes increasingly operative when H+ ions are intercalated easily into the enhanced van der Waals gap of layered material α-Fe2O3 in Au-α-Fe2O3-Mn3O4 nanocomposite. Theoretical studies have shown an enhancement of van der Waals gap which is attributed to the intercalation of Au into the layers of α-Fe2O3. Structural and compositional characterizations have been carried out in detailed by different physical methods and are supported by theoretical studies. Electrochemical measurements show excellent specific capacitance of 580 F g−1 at 1 A g−1 along with improved capacity retention compared to the mother component α-Fe2O3 (205 F g−1 at 1 A g−1) in 0.5 M H2SO4 electrolyte in a potential window of 1.2 V. Further, electrokinetic measurements revealed that total charge stored in the nanocomposite is based on a dominant capacitive mechanism (70% of the total capacitance) along with diffusive mechanism (30% of the total capacitance) at scan rate 5 mV s−1 whereas, α-Fe2O3 exhibits 34% capacitive and 66% diffusive at same scan rate. The synthesized composite nanorod as an efficient electrode material in a solid-state symmetric supercapacitor device exhibits excellent energy density of 36.12 Wh kg−1 and power density of 1994 W kg−1 at 1 A g−1 and 10 A g−1, respectively with outstanding stability (89%) up to 2000 successive charge-discharge cycles at 10 A g−1. This work may offer a new scope for further development of intercalation pseudocapacitive nanomaterials towards achieving high energy storage supercapacitors. © 2019 Elsevier Ltd

Electrochimica Acta

Intercalation pseudocapacitance in chemically stable Au-α-Fe2O3-Mn3O4 composite nanorod: Towards highly efficient solid-state symmetric supercapacitor device

Hydroxyapatite doped with disparate ions is synthesized by Sol-gel technique. Hydroxyapatite is a widely bio-ceramic material for orthopedics and dental applications with weak mechanical strength. The hydroxyapatite doped with various ions which is often reported to enhance mechanical strength and to control bacterial infections. The aim of the work concentrates to improve the hardness of the material. Antibacterial activity enhances with the ions which combine with hydroxyapatite. These effects noticeably reveal that the hydroxyapatite can be well utilized with doping ions in order to develop their efficiency against the various bacterial strains. The effect of co-dopants investigated on their phase structure, bond formation, surface and optical properties are studied using X-ray diffraction technique, Fourier Transform Infra-red analysis, Atomic Force Microscopy and Ultraviolet–Visible spectroscopy. The crystalline size of all the synthesized materials varies from 39 to 49 nm. All the composites exhibit hexagonal crystal structure. The functional groups confirm the bonding formation of prepared samples. The surface roughness of hydroxyapatite were successfully analyzed and observed that the dopants increase the roughness. The dielectric property explains the space charge polarization is present at low frequency and negative temperature coefficient of resistance in the prepared samples. The addition of ions improves the mechanical properties of host materials, which well suitable for coating on implantation devices and for various medical applications. © 2019 Elsevier B.V.

Department of Analytics

School of Computer Science and Engineering

Materials Chemistry and Physics

Study of structural, mechanical and dielectrical properties of ions doped apatite for antibacterial activity

Hydroxyapatite is a&nbsp;well-known calcium phosphate that finds application in various fields, particularly in the field of medicine due to its excellent biocompatibility. In this present work, pure HAp was synthesized by chemical precipitation technique and compared with HAp in presence of&nbsp;Joncryl61, 3-aminopropyltrimethoxysilane and gelatin. FE-SEM&nbsp;and HR-TEM&nbsp;images confined with the variation in morphology like a rod, agglomerated rod, and rod with small sphere dumb-bell&nbsp;structure and the particle size was found in the range of 20nm to 80nm. In vitro antibacterial study was determined by well diffusion method and the tested materials effectively killed pathogens at all the concentrations. The highest concentration of 100μg/well showed good activity range between 20-35mm of the ZOI. MTT test was done for assessing their biocompatibility. The results indicated that all the compounds showed EC50 greater than 300&nbsp;μg/ml which shows that the compounds are less toxic to the tested cell line. © 2019, © 2019 Informa UK Limited, trading as Taylor &amp; Francis Group.

Materials Technology

Biocompatibility and antibacterial study of Hydroxyapatite coupled with Joncryl61, 3-aminopropyltrimethoxysilane and gelatin using an MG-63 Osteoblast cell lines

Purpose: The purpose of the current study is to (i) investigate the feasibility of utilizing the XRV-124 – a cone-shaped scintillation detector – to measure the spot size and spot position in pencil beam scanning proton therapy, and (ii) compare the spot sizes acquired by the XRV-124 with that of the widely used Lynx detector. Methods: Spot position was tested by delivering a map of 30 spots at different locations to the XRV-124. Spot position test included energies 70–210 MeV. Spot size measurements were performed at the isocenter using the XRV-124 and Lynx detectors for a total of 32 energies (70–225 MeV at an increment of 5 MeV) at four cardinal gantry angles. Results: The position (X, Y, and Z) of the radiation isocenter was within ±0.3 mm. For spots placed on the horizontal (X) and longitudinal (Y) axes of the spot map, both the X and Y locations of the spots were within ±0.5 mm. The spots placed diagonally in the map showed a higher deviation (±0.9 mm). In evaluating spot sizes acquired using the XRV-124 vs. Lynx, the results from the XRV were found to be slightly higher but within 0.2 mm for energies ≥130 MeV and within 0.4 mm for energies &lt;130 MeV. Conclusions: It is feasible to utilize the XRV-124 to perform the quality assurance of position and size of a pencil proton beam around the radiation isocenter but within the usable XRV-124 cone area.

Physica Medica

Feasibility study of utilizing XRV-124 scintillation detector for quality assurance of spot profile in pencil beam scanning proton therapy

The present work attempts to design graphene based plasmonic printed dipole and patch antenna resonating at 1 THz. These antennas are compared with their metal versions to bring out the reduction in the antenna length. The antenna parameters such as return loss and radiation pattern are studied and verified with the standard results of the metal counterpart. © 2019 IEEE.

Department of Communication Engineering

School of Electronics Engineering

TENCON 2019 - 2019 IEEE Region 10 Conference (TENCON)

Analysis of Graphene Based Planar Antennas for Terahertz Application

In recent years, exponential growth in population and accompanying surges in energy demands have created huge power requirements. This study explores pork lard methyl ester (PLME) produced from waste pork lards, an economically competitive contender to food grade oils. Using pork lards for biodiesel production serves the dual purpose of cheap biodiesel production and safe disposal of pork lards from meat processing facilities. The objective of this study is to compare the performance, emission, and combustion characteristics of PLME20-fuelled diesel engines under different combinations of injection pressures and injection timings. Experimental results have shown that efficiency is increased by 3% when injection pressure is increased to 240 bar with retarded injection timing of 21° before top dead center (bTDC) at full load. The brake-specific energy consumption is found to decrease by 1.88 MJ/kWh for the same blend (PLME20 at 240 bar, 21° bTDC). In the emission point of view, hydrocarbon and carbon monoxide emissions are found to be decreased drastically for increased pressure with retardation of injection timing. However, nitrogen oxide emission is found to be increased for higher injection pressures. Hence, PLME of 20% blend in compression ignition engine exhibits better characteristics with the higher injection pressures and retardation of injection timing. Abbreviations: PLME: pork lard methyl ester; PLME20: diesel 80% + pork lard methyl ester 20%; ASTM: American Society for Testing and Materials; BMEP: brake mean effective pressure; BSFC: brake-specific fuel consumption; BSEC: brake-specific energy consumption; bTDC: before top dead center; BTE: brake thermal efficiency; BSCO: brake-specific carbon monoxide; BSHC: brake-specific hydrocarbon; BSNOX: brake-specific oxides of nitrogen; CHRR: cumulative heat release rate; CI: compression ignition; CO2: carbon dioxide; DI: direct injection; IP: injection pressure; IT: injection timing; FIP: fuel injection pressure; FIT: fuel injection timing; HRR: heat release rate; KOH: potassium hydroxide; LHV: lower heating value; ND: neat diesel; NOx: nitrogen oxide; WPL: waste pork lards. © 2019, © 2019 Taylor &amp; Francis Group, LLC.