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

We report the meticulous study of freshly synthesized rare earth element substituted R-FeO3 (R-Gd) orthoferrite via co-precipitation route and subsequent sintering. The R-FeO3 powder sample is characterized by X-ray Diffractometer (XRD) for the investigation of crystal structure and is confirmed as orthorhombic with space group Pbnm structure. Nanoparticle dimension is captured by Scanning Electron microscope (SEM). Magnetic character of the sample is examined using vibrating sample magnetometer (VSM), it discloses a nearly linear magnetisation behaviour (paramagnetic behaviour). Dielectric studies and electric Polarization (PE loop) are investigated. A shift is observed in the dielectric constant εr from 250 °C to 300 °C. The Rietveld refinement of the crystal structure from the powder XRD confirms GdFeO3 is distorted at octahedral site of FeO6. This distortion is ascertained as weak Jahn -Teller's distortion leads to the unsaturated electric polarization. The electronic properties, total and partial density of states of GdFeO3 are studied and calculated using Tight - Binding Linear Muffin-Tin Orbital (TBLMTO) method with the Atomic Sphere Approximation (ASA). The band gap of the GdFeO3 is found to be 0.32 eV. © 2018 Elsevier B.V.

World University root node

Mathematics

School of Advanced Sciences

Chennai Campus

Vellore Campus

Journal of Alloys and Compounds

Band structure calculation and rietveld refinement of nanoscale GdFeO3 with affirmation of Jahn Teller's distortion on electric and magnetic properties

Current research on the application of nanoferrites as an electrode material for Li-ion batteries (LIBs) has reached a tremendously high level. The structural, electrical, and optical properties of nanoferrite materials for LIBs have been characterized in several studies. The intention in the present study was to introduce new ferrite materials for improving the cyclic property and efficiency of Li batteries and to provide further characterization of the optical and electrical properties of these CoLi x Fe 1-x O 4 nanoferrites synthesized using a sol-gel combustion technique. Moreover, the synthesized CoLi x Fe 1-x O 4 ferrite samples were characterized by identifying their structural, electrical, and optical properties. A UV analysis illustrated a decrease in the bandgap energy values with increasing Li concentration, while a Fourier transform-infrared spectroscopy study confirmed a spinel ferrite structure. Electrochemical performance of the synthesized CoLi x Fe 1-x O 4 nanoferrites showed an initial coulombic efficiency of 80% and an initial discharge capacity of 1258 mAh g −1 . © 2019 Elsevier B.V.

Materials Chemistry and Physics

The influence of lithium on the optical and electrical properties of CoLixFe1-xO4 nanoferrites

Magnesium doped Ni ferrite nanoparticle (Ni1-xMgxFe2O4) has been synthesized by sol-gel combustion method and it has been analyzed using XRD, UV, FTIR and electrochemical charge-discharge studies. The observed XRD result confirms the nanostructure and it ranges from 23 to 28 nm. Furthermore, band gap energy values and functional group elements have been observed by UV and FTIR, respectively. The lattice constant values varies slightly with respect to magnesium concentration. The band gap energy values increase at the calcination temperature of 500 °C as 0.85, 1.15, 1.2, and 1.45 eV and it decreases when it was calcined at 900 °C as 1.3, 1.25, 1.15, 1.1 eV for x = 0.25, 0.5, 0.75, 1, respectively. The voltage profiles of Ni1-xMgxFe2O4 nanoparticle electrodes show the discharge and charge capacities of 1021 and 718 mAh/g at 500 °C and 1099 and 747 mAh/g at 900 °C, respectively. The high reversible capacities for the Mg doped Ni ferrite nanoparticle electrodes are confirmed as anode materials for Li ion batteries. © 2018 Elsevier B.V.

Physica E: Low-dimensional Systems and Nanostructures

Impact of magnesium substitution in nickel ferrite: Optical and electrochemical studies

An N-Substituted 1H-indole derivative having an empirical formula C16H13NO3S was synthesized by the <a href="https://www.sciencedirect.com/topics/chemistry/condensation">condensation</a> of 2-Methyl-1H-Indole-3-carbaldehyde and benzene <a href="https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/sulfonyl">sulfonyl</a> chloride in presence of a <a href="https://www.sciencedirect.com/topics/chemistry/phase-transfer-catalyst">phase transfer catalyst</a> of type <a href="https://www.sciencedirect.com/topics/chemistry/quaternary-ammonium-salt">quaternary ammonium salt</a> in basic conditions. Then the compound was characterized by using FT-IR, <a href="https://www.sciencedirect.com/topics/chemistry/ultraviolet-spectrum">UV–Visible</a> and NMR spectroscopic methods. Thus the obtained experimental results were effectively compared with DFT studies in arriving the structural characteristics of the title compound. From vibrational analysis, it was observed that carbonyl frequency is somewhat lower than a typical aldehydic stretching frequency and it could be possible only when the <a href="https://www.sciencedirect.com/topics/chemistry/formyl-group">formyl group</a> is coplanar with the ring and subsequent resonance conjugation reduces its force constant. Similarly, the <a href="https://www.sciencedirect.com/topics/chemistry/absorptivity">optical absorption</a> behavior of a typical <a href="https://www.sciencedirect.com/topics/chemistry/indole">indole</a> ring suffered from a bathochromic shift due to the presence of ring substituents. Finally, the molecular drug docking studies of the title compound were performed using <a href="https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/autodock">AutoDock</a> 4.2 tools to ascertain its binding mode, efficiency and the nature of chemical interactions with the target proteins and it has been predicted theoretically that the binding efficiency of the ligand on the target receptor surface was found to be better in the case of <a href="https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/gram-positive-bacterium">Gram positive bacteria</a> S. Aureus than the Gram negative N. Meningitidis.

VIT Unitversity

Journal of Molecular Structure

Synthesis, spectroscopic, computational and drug docking studies of 1-(benzenesulfonyl)-2-methyl-1H-indole-3-carbaldehyde

Wind Engineering

Co-simulation and hardware implementation of multi-port rectifier for power system and renewable energy applications

In the present study, Ti-15V-3Al-3Cr-3Sn (Ti-15-3), a beta titanium aerospace alloy in solution treated condition (850 °C/1 h) was subjected to Laser Peening without Coating (LPwC) with a wavelength of 532 nm and power density of 8.96 GW cm−2. Surface roughness was analysed using 3D optical topography. Curiously, in the near peened surface, peening induced precipitation (i.e. 19% of α precipitation) and increased fraction of low angle boundaries (∼123%) was revealed through the Electron Back Scattered Diffraction (EBSD) analysis. Through depth nanohardness measurement was carried out along the cross-section of the peened sample right from the near peened surface. Peak hardness of 4.6 GPa is observed at a depth of 100 µm from the peened surface while the base/bulk hardness of the material is 4 GPa. In addition, X-Ray Diffraction (XRD) based analysis confirmed the presence of compressive residual stress in the near surface region of the peened sample. To understand the effect of the peening induced microstructural changes and residual stresses in fatigue behaviour, staircase method of fatigue analysis was adopted and observed that the more number of run out samples belonged to laser peened condition when compared to the unpeened condition. Despite this favourable indication, fatigue limit remains more or less unaltered even after peening. Fractography studies revealed the least influence of the surface roughness induced by laser peening over the crack initiation. Irrespective of the condition (i.e. unpeened and laser peened), crack initiation was predominantly influenced by the stress concentration co-existing at the sharp corners. © 2018 Elsevier Ltd

Optics & Laser Technology

Influence of laser peening without coating on microstructure and fatigue limit of Ti-15V-3Al-3Cr-3Sn

Purpose: The main purpose of this study is to demonstrate the clinical implementation of a comprehensive pencil beam scanning (PBS) daily quality assurance (QA) program involving a number of novel QA devices including the Sphinx/Lynx/parallel-plate (PPC05) ion chamber and HexaCheck/multiple imaging modality isocentricity (MIMI) imaging phantoms. Additionally, the study highlights the importance of testing the connectivity among oncology information system (OIS), beam delivery/imaging systems, and patient position system at a proton center with multi-vendor equipment and software. Methods: For dosimetry, a daily QA plan with spot map of four different energies (106, 145, 172, and 221&nbsp;MeV) is delivered on the delivery system through the OIS. The delivery assesses the dose output, field homogeneity, beam coincidence, beam energy, width, distal-fall-off (DFO), and spot characteristics — for example, position, size, and skewness. As a part of mechanical and imaging QA, a treatment plan with the MIMI phantom serving as the patient is transferred from OIS to imaging system. The HexaCheck/MIMI phantoms are used to assess daily laser accuracy, imaging isocenter accuracy, image registration accuracy, and six-dimensional (6D) positional correction accuracy for the kV imaging system and robotic couch. Results: The daily QA results presented herein are based on 202 daily sets of measurements over a period of 10&nbsp;months. Total time to perform daily QA tasks at our center is under 30&nbsp;min. The relative difference (Δ rel ) of daily measurements with respect to baseline was within&nbsp;±&nbsp;1% for field homogeneity, ±0.5&nbsp;mm for range, width and DFO, ±1&nbsp;mm for spots positions, ±10% for in-air spot sigma, ±0.5 spot skewness, and ±1&nbsp;mm for beam coincidence (except 1 case: Δ rel &nbsp;=&nbsp;1.3&nbsp;mm). The average Δ rel in dose output was −0.2% (range: −1.1% to 1.5%). For 6D IGRT QA, the average absolute difference (Δ abs ) was ≤0.6&nbsp;±&nbsp;0.4&nbsp;mm for translational and ≤0.5° for rotational shifts. Conclusion: The use of novel QA devices such as the Sphinx in conjunction with the Lynx, PPC05 ion chamber, HexaCheck/MIMI phantoms, and myQA software was shown to provide a comprehensive and efficient method for performing daily QA of a number of system parameters for a modern proton PBS-dedicated treatment delivery unit.

Fulltext

Journal of Applied Clinical Medical Physics

Development and long‐term stability of a comprehensive daily QA program for a modern pencil beam scanning ( PBS ) proton therapy delivery system

Nanocrystalline FeMnO 3 was synthesized by sol-gel method using succinic acid as a chelating agent. The structural and morphological characterizations of the synthesized material were carried out by using XRD, FT-IR, and SEM with EDX. The hysteresis loop at room temperature shows the antiferromagnetic behavior of the material. The variation in the frequency and temperature dependent dielectric constant illustrated the Maxwell-Wagner relaxation in the sample. Nyquist plot illustrated the grains resistance at higher frequency whereas at lower frequency it is dominated by the grain boundary resistance. The electrical modulus also confirms the relaxation process. The activation energy calculation of impedance and modulus shows the existence of oxygen vacancy. XPS analysis confirmed the existence of oxygen vacancy and different oxidation states of Fe 3+ /Fe 2+ and Mn 3+ /Mn 4+ in the material. Conductivity studies of the material were analyzed and fitted by using Jonscher Power law. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.

Ionics

Investigation on structural and electrical properties of FeMnO3 synthesized by sol-gel method

Known as a hard magnetic material, cobalt ferrite belongs to one of the most attractive classes of materials owing to its diverse technical applicability such as in catalysis, sensors, batteries. In this study, we synthesized Li- and Y-substituted cobalt ferrite nanoparticles using a sol–gel combustion method. Their mean crystallite sizes with spinel structures were calculated as 15–19 and 2–5 nm and their lattice constant values were 7.8 ± 0.02 and 8.5 ± 0.3 Å, respectively. The results also revealed that the band gap energy values of the prepared Li- and Y-doped cobalt ferrites decreased after doping compared with that of pure cobalt ferrite, and thus they appear to be promising for energy generation and storage applications. © 2018, Indian Association for the Cultivation of Science.