Effect of titania on the microstructure evolution of sintered magnesite in correlation with its properties

Natural Indian magnesite contains large amount of impurities like CaO, SiO2 and Fe2O3. On heat treatment, these impurities chemically react and form low melting phases like monticellite (CMS), merwinite (C3MS2) and vitreous phases, which degrade the refractory properties of magnesite like hot modulus of rupture, corrosion resistance etc. In the present investigation, TiO2 was used to reduce the formation of low melting phases. Compacted green pellets and bars of magnesite containing 0-5 wt% TiO2 were sintered in the temperature range of 1500 1600 degrees C with 2 h soaking at peak temperature. It was observed that TiO2 slightly increased the apparent porosity and decreased the bulk density by reducing the formation of low melting phases. High temperature flexural strength increases with TiO2 content upto 3 wt% followed by slight decrease in strength after further increase in the amount of additive. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved

Measurements of dose rate for 10-16 keV Synchrotron X-ray photons at BL-16 beam line of Indus-2

Indus-2 is a 2.5 GeV electron synchrotron radiation source located at Raja Ramanna Centre for Advanced Technology (RRCAT), India. There is significant radiation exposure in the direct beam of synchrotron radiation due to its intense flux and low energy at synchrotron radiation beam line. In this paper, measurements of absorbed dose rate for mono chromatic synchrotron X-ray photon of energy ranging 10-16 keV is presented using various types of passive dosimeters, like CaSO4(Dy) TLDs, LiF :Mg,Ti (TLD-100), and Gafchromic film EBT-2 at microfocus X-ray fluorescence spectroscopy beam line (BL-16). The measured results are also compared with theoretically calculated values. It is observed that LiF :Mg,Ti (TLD-100), and Gafchromic film EBT-2 show 3-6 times more absorbed dose rates as compared to calculated values whereas CaSO4(Dy) TLD shows 10-20 times more absorbed dose rates

Efficient solar light photoreduction of CO2 to hydrocarbon fuels via magnesiothermally reduced TiO2 photocatalyst

Elevated atmospheric CO2 levels are recognized as a key driver of global warming. Making use of sunlight to photoreduce CO2, in turn fabricating hydrocarbon fuels compatible with the current energy infrastructure, is a compelling strategy to minimize atmospheric CO2 concentrations. However, practical application of such a photocatalytic system requires significant efforts for improved photoreduction performance and product selectivity. Herein, we investigate the performance of our newly developed reduced TiO2, prepared by a reduction process using Mg in 5% H2/Ar, for photoconversion of CO2 and water vapor to hydrocarbons, primarily CH4. Using Pt nanoparticles as a co-catalyst, under simulated solar light irradiation the reduced anatase TiO2 exhibits a relatively stable performance with a threefold increase in the rate of CH4 production (1640.58 ppm g−1 h−1, 1.13 μmol g−1 h−1) as compared to anatase TiO2 nanoparticles (546.98 ppm g−1 h−1, 0.38 μmol g−1 h−1). The improved photocatalytic performance is attributed to enhanced light absorption, suitable band edge alignment with respect to the CO2/CH4 redox potential, and efficient separation of photogenerated charges. Our results suggest that the Pt-sensitized reduced TiO2 can serve as an efficient photocatalyst for solar light CO2 photoreduction. © 2017 Elsevier B.V

In vitro Antioxidant Potential of Different Parts of Oroxylum indicum: A Comparative Study

The present study evaluated the in vitro antioxidant potential of different parts of Oroxylum indicum. 2,2-diphelyl 1-picrylhydrazyl (DPPH), nitric oxide, superoxide anion and hydroxyl radical scavenging potential and reductive ability assay of methanol extract of different parts i.e. root, root bark, stem, stem bark, leaves and fruits were performed. Leaves and bark extracts exhibits highest free radical scavenging activity than bark, stem and fruit extract. Leaves extract showed maximum reductive ability and found to contain maximum amount of polyphenolic compounds. The highest free radical activity may be due to presence of polyphenolic compounds