Nanoscale Investigation of Grain Growth in RF-Sputtered Indium Tin Oxide Thin Films by Scanning Probe Microscopy

This work studied the electronic characteristics of the grains and grain boundaries of indium tin oxide (ITO) thin films using electrostatic and Kelvin probe force microscopy. Two types of ITO films were compared, deposited using radiofrequency magnetron sputtering in pure argon or 99% argon + 1% oxygen, respectively. The average grain size and surface roughness increased with substrate temperature for the films deposited in pure argon. With the addition of 1% oxygen, the increase in the grain size was inhibited above 150°C, which was suggested to be due to passivation of the grains by the excess oxygen. Electrostatic force microscopy and Kelvin probe force microscopy (KPFM) images confirmed that the grain growth was defect mediated and occurred at defective interfaces at high temperatures. Films deposited at room temperature with 1% oxygen showed crystalline nature, while films deposited with pure argon at room temperature were amorphous as observed from KPFM images. The potential drop across the grain and grain boundary was determined by taking surface potential line profiles to evaluate the electronic properties.     

Wear and friction behavior of alloyed gray cast iron with solid lubricants under boundary lubrication

Friction and wear behavior of MoS₂, boric acid, graphite and TiO₂ has been compared under extreme boundary lubrication condition. Boundary lubrication was simulated for the study. Results show that MoS₂ and graphite were 30-50% more effective than other two lubricants. Friction coefficient shows a decreasing trend with increase in sliding speed due to increasing temperature and higher shear force. High friction coefficient values were recorded for all the lubricants (0.2-0.5). This is due to predominating solid interactions during boundary lubrication condition. Boric acid and TiO₂ were not much effective in lubrication.     

Enhanced heterogeneous ferrioxalate photo-fenton degradation of reactive orange 4 by solar light

A combined homogeneous and heterogeneous photocatalytic decolourisation and degradation of a chlorotriazine Reactive azo dye Reactive Orange 4 (RO4) have been carried out using ferrous sulphate/ ferrioxalate with H₂O₂ and TiO₂-P25 particles. Solar/ferrous/H₂O₂/TiO₂-P25 and solar/ferrioxalate/H₂O₂/TiO₂-P25 processes are found to be more efficient than the individual photo-Fenton and solar/TiO₂-P25 processes. A comparison of these two processes with UV/ferrous/H₂O₂/TiO₂-P25 and UV/ferrioxalate/H₂O₂/TiO₂-P25 reveals that ferrioxalate is more efficient in solar light whereas ferrous ion is more efficient in UV light. The experimental parameters such as pH, initial H₂O₂, Fe²⁺, ferrioxalate and TiO₂-P25 concentration strongly influenced the dye removal rate in solar processes. The optimum operating conditions of these two combined processes are reported.     

A novel nanostructured iron oxide-gold bioelectrode for hydrogen peroxide sensing

Fe(3)O(4) nanoparticles covalently linked to a gold electrode have been used for immobilizing catalase (CAT) enzyme to sense the presence of various concentrations of H(2)O(2). These nanoparticles ranging from 20 to 30 nm were synthesized by thermal co-precipitation of ferric and ferrous chlorides. SEM and XRD have been used for morphological and structural characterization of Fe(3)O(4) nanoparticles. CAT enzyme was linked covalently to the surface of iron oxide using carbodiimide in phosphate buffer (pH 7.4) at 4?°C. The enzyme-iron oxide link was confirmed by FT-IR spectroscopy. Sensing studies carried out using cyclic voltammetry showed a linear response of the CAT/nano Fe(3)O(4)/Au bioelectrode towards H(2)O(2) between 1.5 and 13.5 μM with a very sharp response time of 2 s.     

Estimation of wind power availability in Tamil Nadu

Eleven years' daily wind speed data at 21 locations in the state of Tamil Nadu, India were analysed to assess the available wind power potential using Weibull distribution under two different methods. The mean wind speed varied from 1.0 to 5.0 m/s dividing the state into four regions. Judged by mean and standard deviation of available wind power, six locations have been identified as possible sites for a wind energy system.     

As(V) removal using carbonized yeast cells containing silver nanoparticles

The present study involves the development of adsorbent containing silver nanoparticles for arsenate removal using silver reducing property of a novel yeast strain Saccharomyces cerevisiae BU-MBT-CY1 isolated from coconut cell sap. Biological reduction of silver by the isolate was deduced at various time intervals. The yeast cells after biological silver reduction were harvested and subjected to carbonization at 400 °C for 1 h and its properties were analyzed using Fourier Transform Infra-Red spectroscopy, X-ray diffraction, scanning electron microscope attached with energy dispersive spectroscopy and transmission electron microscope. The average size of the silver nanoparticles present on the surface of the carbonized silver containing yeast cells (CSY) was 19 ± 9 nm. The carbonized control yeast cells (CCY) did not contain any particles on its surface. As(V) adsorption efficiency of CCY and CSY was deduced in batch mode by varying parameters like contact time, initial concentration, and pH. Desorption studies were also carried out by varying the pH. The experimental data were fitted onto Langmuir and D-R Isotherms and Lagergren and pseudo second order kinetic models. The CSY was more efficient in arsenate removal when compared to CCY.     

SoftUDC: a software-based data center for utility computing

Utility computing aims to aggregate server, network, and storage systems into a single, centrally managed pool of resources. SoftUDC, a virtual machine monitor, lets applications and administrative domains share physical resources while maintaining full functional isolation.     

CO2 laser processing for reducing core loss of cold-rolled grain-oriented silicon steel

Non-contact processing technique involving the use of CW and pulsed CO₂ laser irradiation has been used for reducing the core loss of cold-rolled grain-oriented silicon steel. Laser scribing perpendicular to the rolling direction resulted in a refinement of domain wall spacing which subsequently reduced the loss of silicon steel. It was found that laser irradiation was more effective in a specimen with higher magnetic induction (Hi-B) and the loss was reduced by more than 10% under optimum conditions of the laser irradiation and the scribing speed. Since laser processing is a non-contact technique, it can be easily applied to the production line of the silicon steel.