Synthesis and characterization of silver nanoparticles using Gelidium amansii and its antimicrobial property against various pathogenic bacteria.

Microfouling is evolving at a fast rate causing augmented mortality rates and damage worldwide. Until now, several remedial measures have been exploited to overcome microfouling, amongst them nanoparticles play a superior role. Currently, green synthesized nanoparticles have been centered owing to its eco-friendly, cost effectively and non-toxic nature which has also increased its industrial applications (biomedicine, food and textile).

A Study on Doped Heterojunctions in TiO Nanotubes: An Efficient Photocatalyst for Solar Water Splitting.

The two important factors that affect sunlight assisted water splitting ability of TiO are its charge recombination and large band gap. We report the first demonstration of nitrogen doped triphase (anatase-rutile-brookite) TiO nanotubes as sun light active photocatalyst for water splitting with high quantum efficiency. Nitrogen doped triphase TiO nanotubes, corresponding to different nitrogen concentrations, are synthesized electrochemically.

A REVIEW ON VARIATION OF NATURAL RADIOACTIVITY ALONG THE SOUTHEAST COAST OF TAMIL NADU FOR THE PAST 4 DECADES (1974-2016).

This review deals with natural radioactivity variation along the southeast coast of Tamil Nadu for the past four decades (1974-2016). About 40 research works have been conducted along the coast since 1974 in various environmental matrices using a variety of experimental methods. For these measurements researchers are adopted different experimental methods.

Water quality assessment of the ecologically stressed Hooghly River Estuary, India: A multivariate approach.

Spatio-temporal and seasonal variation of the water quality characteristics of the Hooghly River Estuary, India were studied considering eight stations of diverse eco-hydrological characteristics. Wide variations in turbidity, total dissolved solids and fecal coliform exceeded the permissible BIS drinking water level limit. The estuary is observed to be relatively low-oxygenated, mesotropic and phosphate limiting.

Spectroscopically forbidden infra-red emission in Au-vertical graphene hybrid nanostructures.

Implementation of Au nanoparticles (NPs) is a subject for frontier plasmonic research due to its fascinating optical properties. Herein, the present study deals with plasmonic assisted emission properties of Au NPs-vertical graphene (VG) hybrid nanostructures. The influence of effective polarizability of Au NPs on the surface enhanced Raman scattering and luminescence properties is investigated.

Transmission electron microscopy studies and modeling of 3D reciprocal space of ω forming alloy.

Initial stage of ω phase formation and associated anomalous features that appear in diffraction patterns of a metastable β transition metal alloy have been investigated in this study with the aid of transmission electron microscopy, simulation and modeling. The paper explores discrete features that emerge in selected area diffraction patterns of quenched Ti-15wt%Mo alloy and analyzes the correlation between ω reflections and diffuse arcs by considering all variants of ω phase as per the formation kinetics of ω phase in β matrix while quenching. Superimposed simulated diffraction patterns have been compared with experimental counterparts and it is deduced that there is lack of congruence between ω reflections and diffuse arcs even after considering trigonal ω with varying degrees of displacement.

Process-specific mechanisms of vertically oriented graphene growth in plasmas.

Applications of plasma-produced vertically oriented graphene nanosheets (VGNs) rely on their unique structure and morphology, which can be tuned by the process parameters to understand the growth mechanism. Here, we report on the effect of the key process parameters such as deposition temperature, discharge power and distance from plasma source to substrate on the catalyst-free growth of VGNs in microwave plasmas. A direct evidence for the initiation of vertical growth through nanoscale graphitic islands is obtained from the temperature-dependent growth rates where the activation energy is found to be as low as 0.

Duality and quantum state engineering in cavity arrays.

A system of two coupled cavities with N - 1 photons is shown to be dynamically equivalent to an array of N coupled cavities containing one photon. Every transition in the two cavity system has a dual phenomenon in terms of photon transport in the cavity array. This duality is employed to arrive at the required coupling strengths and nonlinearities in the cavity array so that controlled photon transfer is possible between any two cavities.

Impingement of marine organisms in a tropical atomic power plant cooling water system.

A one-year impingement monitoring was conducted at Madras Atomic Power Station (MAPS), Kalpakkam, southeastern coast of India and identified a total of 67 species of marine organisms in the cooling water system. Estimates of total annual impingement contributed about 1.47×10 individuals and 142.

Conformational Landscape of Tri-n-butyl Phosphate: Matrix Isolation Infrared Spectroscopy and Systematic Computational Analysis.

The conformations of tri-n-butyl phosphate (TBP) were studied using matrix isolation infrared spectroscopy and density functional theory (DFT) calculations. TBP was trapped in a N matrix using both effusive and supersonic sources, and its infrared spectra were recorded. The computational exploration of TBP is a very demanding problem to confront, due to the presence of a large multitude of conformations in TBP.

Occurrence of spintronics behaviour (half-metallicity, spin gapless semiconductor and bipolar magnetic semiconductor) depending on the location of oxygen vacancies in BiFeNiO.

The current communication signifies the effect of oxygen vacancies (OVs) both qualitatively and quantitatively in multiferroic BiFeNiO by an in-depth atomic-level investigation of its electronic structure and magnetization properties, and these materials have a variety of applications in spintronics, optoelectronics, sensors and solar energy devices. Depending on the precise location of OVs, all the three types of spintronic material namely half-metallic, spin gapless semiconductor and bipolar magnetic conductor have been established in a single material for the first time and both super-exchange and double-exchange interactions are possible in accordance with the precise location of OVs. We have also calculated the vacancy formation energies to predict their thermodynamic stabilities.

Assessment of Heavy Metal Contamination in Marine Sediments of East Coast of Tamil Nadu Affected by Different Pollution Sources.

The aim of this study was to determine the concentration of heavy metals in the sediments of Periyakalapet to Parangipettai coast, east coast of Tamil Nadu, by using energy-dispersive X-ray fluorescence (EDXRF) technique. The average heavy metal concentrations in the sediment samples were found in the order Al>Fe>Ca>Ti>K>Mg>Mn>Ba>V>Cr>Zn>La>Ni>Pb>Co>Cd>Cu. The average heavy metal concentrations were below the world crustal average.

Tunable transport property of oxygen ion in metal oxide thin film: Impact of electrolyte orientation on conductivity.

Quest for efficient ion conducting electrolyte thin film operating at intermediate temperature (~600 °C) holds promise for the real-world utilization of solid oxide fuel cells. Here, we report the correlation between mixed as well as preferentially oriented samarium doped cerium oxide electrolyte films fabricated by varying the substrate temperatures (100, 300 and 500 °C) over anode/ quartz by electron beam physical vapor deposition. Pole figure analysis of films deposited at 300 °C demonstrated a preferential (111) orientation in out-off plane direction, while a mixed orientation was observed at 100 and 500 °C.

Robust water repellent ZnO nanorod array by Swift Heavy Ion Irradiation: Effect of Electronic Excitation Induced Local Chemical State Modification.

Tailoring the surface properties by varying the chemistry and roughness could be of interest for self-cleaning applications. We demonstrate the transformation of hydrophobic ZnO Nano rod (NR) array into superhydrophobic nature by changing the local chemical state and without altering the surface roughness by swift heavy ion (SHI) irradiation. The aligned ZnO NR arrays were irradiated using 150 MeV Ag ions with different fluences from 5E10 to 3E12 ions/cm.

Green Synthesized Zinc Oxide (ZnO) Nanoparticles Induce Oxidative Stress and DNA Damage in Lathyrus sativus L. Root Bioassay System.

Zinc oxide nanoparticles (ZnONP-GS) were synthesised from the precursor zinc acetate (Zn(CH₃COO)₂) through the green route using the milky latex from milk weed ( L. R. Br) by alkaline precipitation.

Vibrational spectroscopic and computational studies on diisopropylammonium bromide.

Diisopropylammonium bromide (DIPAB) can be crystallized either in an orthorhombic (P222) or in a monoclinic (P2) structure at room temperature depending on synthesis conditions. The non-polar orthorhombic structure exhibits a subtle, irreversible transformation into the ferroelectric monoclinic-II (m-II) phase above ~421K. At a slightly higher temperature of 426K this m-II (P2) phase reversibly transforms into a disordered, paraelectric monoclinic-I (P2/m) structure.

The influence of carbon concentration on the electronic structure and magnetic properties of carbon implanted ZnO thin films.

The influence of carbon concentration on the electronic and magnetic properties of C-implanted ZnO thin films has been studied using synchrotron radiation based X-ray absorption spectroscopic techniques and vibrating sample magnetometer measurements. 20 keV carbon ions were implanted in ZnO films with different fluences (2 × 10, 4 × 10 and 6 × 10 ions per cm). The pristine ZnO film shows diamagnetic behaviour while the C-implanted films exhibit room temperature ferromagnetism.

Physicochemical properties of nanocomposite: Hydroxyapatite in reduced graphene oxide.

Graphene oxide (GO) based nanocomposites have gained considerable attention in the field of material science due to their excellent physicochemical and biological properties. Incorporation of nanomaterials into GO sheets prevents the formation of π-π stacking bond thereby giving rise to composites that show the improved properties compared to their individual counterparts. In this work, reduced graphene oxide (rGO) - hydroxyapatite (HAP) nanocomposites were synthesized by ultrasonic method.

Area-preserving colour coding of inverse pole figure domain.

The inverse pole figure (IPF) map is a routinely displayed output in microtexture studies, interpreted using the attached colour legend/diagram. An area-preserving relation between the IPF domain and RGB colour domain has been developed here, and the resultant IPF colour diagrams of different crystal point group symmetries are presented.

The role of 1-D finite size Heisenberg chains in increasing the metal to insulator transition temperature in hole rich VO.

VO samples are grown with different oxygen concentrations leading to different monoclinic, M1, and triclinic, T, insulating phases which undergo a first order metal to insulator transition (MIT) followed by a structural phase transition (SPT) to the rutile tetragonal phase. The metal insulator transition temperature (T) was found to be increased with increasing native defects. Vanadium vacancy (V) is envisaged to create local strains in the lattice which prevents twisting of the V-V dimers promoting metastable monoclinic, M2 and T phases at intermediate temperatures.

Delineating the role of ripples on the thermal expansion of 2D honeycomb materials: graphene, 2D h-BN and monolayer (ML)-MoS.

We delineated the role of thermally excited ripples on the thermal expansion properties of 2D honeycomb materials (free-standing graphene, 2D h-BN, and ML-MoS), by explicitly carrying out three-dimensional (3D) and two-dimensional (2D) molecular dynamics simulations. In 3D simulations, the in-plane lattice parameter (a-lattice) of graphene and 2D h-BN shows thermal contraction over a wide range of temperatures and exhibits a strong system size dependence. The 2D simulations of the very same system show a reverse trend, where the a-lattice expands in the whole computed temperature range.

Experimental evidence for the blue-shifted hydrogen-bonded complexes of CHF with π-electron donors.

Blue-shifted hydrogen-bonded complexes of fluoroform (CHF) with benzene (CH) and acetylene (CH) have been investigated using matrix isolation infrared spectroscopy and ab initio computations. For CHF-CH complex, calculations performed at the B3LYP and MP2 levels of theory using 6-311++G (d,p) and aug-cc-pVDZ basis sets discerned two minima corresponding to a 1:1 hydrogen-bonded complex. The global minimum correlated to a structure, where the interaction is between the hydrogen of CHF and the π-electrons of CH and a weak local minimum was stabilized through H…F interaction.

Role of oxygen functional groups in reduced graphene oxide for lubrication.

Functionalized and fully characterized graphene-based lubricant additives are potential 2D materials for energy-efficient tribological applications in machine elements, especially at macroscopic contacts. Two different reduced graphene oxide (rGO) derivatives, terminated by hydroxyl and epoxy-hydroxyl groups, were prepared and blended with two different molecular weights of polyethylene glycol (PEG) for tribological investigation. Epoxy-hydroxyl-terminated rGO dispersed in PEG showed significantly smaller values of the friction coefficient.

Elemental distribution and trace metal contamination in the surface sediment of south east coast of India.

Spatial distribution and potential ecological risk of trace metals in the surface sediment of south east coast of India covering eight different ecosystems was studied. The concentration of major elements viz. Ca, Mg, K, Ti and trace metals viz.

Studies on neutron spectrum characterization for the Pneumatic Fast Transfer System (PFTS) of KAMINI reactor.

Characterization of neutron energy spectrum along with the determination of sub-cadmium to epithermal neutron flux ratio (f) and the epithermal neutron flux shape factor (α) has been carried out at pneumatic fast transfer system (PFTS) of KAMINI reactor. The facility has been extensively used for the neutron activation analysis (NAA) studies using both k-NAA and relative method. This paper describes the multi-foil activation method to determine the reaction rates followed by the generation of computed guess spectrum to unfold the neutron spectrum using least square minimization approach.