Solar/visible light photocatalytic dye degradation using BaTi1−xFexO3 ceramics

BaTi_1−xFe_xO₃ compositions (for x = 0, 0.1, and 0.2) were prepared via a solid-state reaction route. The presence of iron (Fe) in barium titanate (BaTiO₃) eventually decreased the energy bandgap; thus, its utilization for water cleaning application through photocatalysis process was explored (using methylene blue [MB] dye as an indicative pollutant in water). Characterization of the synthesized powder was performed through scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy. The bandgap of the synthesized powder was calculated as 3.2, 2.12, and 1.67 eV for BaTi_1−xFe_xO₃ compositions (for x = 0, 0.1, and 0.2), respectively. BaTi_0.8Fe_0.2O₃ powder showed excellent results, and ∼71% of the MB dye (∼5 mg/L concentrated) was degraded using the photocatalysis process under visible light. To check the potentiality of BaTi_1−xFe_xO₃ compositions (for x = 0, 0.1, and 0.2), the photocatalysis process was carried out by changing the concentration of MB dye (2.5–10 mg/L with a step of 2.5 mg/L) and the amount of BaTi_0.8Fe_0.2O₃ powder (0.05–0.2 g with a step of 0.05 g) for ∼5-mg/L concentrated MB dye. The treated water was further used as a growth parameter and phytotoxicity analysis through germination index on the wheat seeds. Lastly, the BaTi_1−xFe_xO₃ compositions (for x = 0, 0.1, and 0.2) were explored for water cleaning applications under real-time solar irradiation.     

Effect of functionalized silicon carbide nano-particles as additive in cross-linked PVA based composites for vibration damping application

In this research study, a comprehensive effort has been made to functionalize silicon carbide particles using the acidic oxidation with nitric acid to obtain homogeneous stabilized distribution of activated SiC particles within a polymer matrix, and develop functionalized silicon carbide (f-SiC) particle reinforced polyvinyl alcohol (PVA) based cross-linked composite. After fabrication of functionalized silicon carbide (f-SiC) particle reinforced polyvinyl alcohol based cross-linked composite with varying f-SiC weight percentages of PVA (0%, 1%, 2%, 3%, and 4%) were placed to various investigations. Processed samples are initially examined based by the physical tests (water absorption tests), followed by mechanical test (tensile test) and then micro-structural tests (scanning electron microscopy). Lastly, thermal tests were also concluded which involved the dynamic mechanical, differential thermal and thermo gravimetric analysis. The cross-linked polyvinyl alcohol-based composite with 2 weight % of f-SiC content is observed to be the superlative of all the compositions under this research study that was confirmed by the mechanical and micro-structural tests. This composite material shows high storage modulus with visco-elastic behavior, therefore, the material can be utilized to diminish the transmission of noise, as a shock absorber and vibration isolator.     

Uranyl ions uptake on poly(AAc/AAm)-cl-N,N-MBAAm hydrogel

In the present article, we report two well-characterized hydrogels for the adsorption of uranyl ions from 5% NaCl solution. The hydrogel was synthesized by free radical initiation from acrylamide and acrylic acid using N,N-methylenebisacrylamide as crosslinker. In order to improve ion uptake performance, the hydrogel was hydrolyzed to partially convert some of the amide groups into carboxylate groups. The uranyl ion adsorption was studied as a function of hydrogel structure, uranyl ions concentration, pH, temperature, and mass of hydrogel. The partially hydrolyzed hydrogel exhibited the maximum uranyl ion uptake of 236.6 mgg⁻¹ in 480 min at 45 °C and at pH 13. Good reproducibility of results was observed and the evidence of sorption at the optimum pH and ion concentration was obtained by comparison of FTIR spectra of the precursor and uranyl ions loaded hydrogels. The performance of both the hydrogels was found to be higher than that of a commercial resin, Amberlite IRC-718. The experimental data shows good match with Langmuir and Freundlich isotherms and pseudo-first order kinetics.     

The VVERs at KudanKulam

A Nuclear Power Project is being set-up at KudanKulam in the state of Tamil Nadu, India in collaboration with the Russian Federation. The project comprises of two units each of 1000 MWe VVER type reactor. The design of the plant and supply of all the major equipment is in the scope of the Russian Federation while development of infrastructure and project construction is in Indian scope of works. The VVER (Version V-412) reactor that is under construction at KudanKulam site is an advanced PWR, which incorporates all the features of a modern PWR as per the current Russian, Western and IAEA standards. The KudanKulam site in the southern Indian state of Tamil Nadu was one among the several sites evaluated by the Site Selection Committee, which cleared KudanKulam site for setting up an installed capacity up to 6000 MWe. The design, construction and operation of the plant meets the regulatory and licensing requirements of Russian regulatory body “RTN” as also India's Atomic Energy Regulatory Board. The supply of the equipment from the Russian Federation is on schedule and the project construction work by various Indian agencies is also ahead of schedule. The two units of KudanKulam Nuclear Power Project (KKNPP) are scheduled to achieve first criticality in the year 2007–2008. The paper discusses various design features, project construction and management aspects.     

Dispersal and sink pathways of suspended particulate matter from the orographically enhanced SWM regime of the SE Arabian Sea

The magnitude of precipitation plays an important role in the yield and supply of terrigenous matter into the sea through fluvial supply. The influence of climate on the influx of total suspended matter (TSM) into the continental margin of the SE Arabian Sea has been evaluated from subweekly synoptic variations in TSM and its advection rates, currents and winds during the southwest monsoon (SWM) and postmonsoon season. Our study endorses the high influx of TSM during the SWM (>82 mg l^?1; advection 26–110 mg m^?2 s^?1), albeit that most of it is sequestered into the shallow coastal region. Over the mid-outer shelf, there is uniformly low TSM (12–24 mg l^?1) and a weak TSM advection (9–4 mg m^?2 s^?1) throughout the year. This trend is persistent also in areas having upwelling-induced high marine productivity. We therefore surmise that higher fluvial influx and primary production during the SWM do not necessarily enhance the supply of particulate matter into the deeper offshore regions of the SE Arabian Sea. We ascribe a vital role to the prevailing morphodynamic processes.     

Characterization and transport of aerosols over the Bay of Bengal during the winter monsoon: a comparative study using in-situ and satellite measurements

Natural processes, such as dust storms and sea salt spray, and anthropogenic activities, such as the burning of fossil fuels and biomass, introduce aerosols into the atmosphere. Their concentration, geographic distribution and particle size promote significant climatic consequences. Aerosol transport processes, from landmasses to oceans, are scarcely understood because of inadequate in-situ observations. This study reports the results of spectral aerosol optical depth (AOD) measurements using a five-channel (380, 440, 500, 675 and 870 nm) handheld MICROTOPS Sun-photometer used during a sea-truth data collection campaign conducted in the central Bay of Bengal (BOB) during the northeastern monsoon period (10 November to 13 December 2007). For the entire cruise period, the mean values of the daily average of the AODs at 500 nm and 870 nm were 0.39 ± 0.065 and 0.22 ± 0.047, respectively, the mean value of the Angstrom exponent (α) was 1.23 ± 0.2 and the turbidity parameter (β) was 0.183 ± 0.044. A smaller α value together with a larger β value suggests the presence of an abundance of smaller aerosol particles near the coast. An air mass back-trajectory analysis was undertaken to identify the potential source regions of the aerosols. Analysis of the results demonstrated the effect of the aerosol transport and source regions on the spectral behaviour of the AODs. In-situ measured AOD (550 nm) and α (550 nm, 865 nm) values were further compared with Moderate Resolution Imaging Spectroradiometer (MODIS)-derived parameters. The in-situ and MODIS-derived AOD values were found to be in good agreement, with a coefficient of determination (R ²) of 0.78 and a standard error of 0.05, while the R ² for α was 0.68 with a standard error of 0.14.     

Preparation and photoluminescent analysis of Sm3+ complexes based on unsymmetrical conjugated chromophoric ligand

Journal of Materials Science: Materials in Electronics - The octa-coordinated complexes of Sm(III) with β-diketone and nitrogen-heterocyclic bidentate auxiliary moiety were prepared and...     

Optimal linear representations of images for object recognition

Although linear representations are frequently used in image analysis, their performances are seldom optimal in specific applications. This paper proposes a stochastic gradient algorithm for finding optimal linear representations of images for use in appearance-based object recognition. Using the nearest neighbor classifier, a recognition performance function is specified and linear representations that maximize this performance are sought. For solving this optimization problem on a Grassmann manifold, a stochastic gradient algorithm utilizing intrinsic flows is introduced. Several experimental results are presented to demonstrate this algorithm.     

New method for threshold voltage extraction of high-voltage MOSFETs based on gate-to-drain capacitance measurement

This letter reports on the extraction of the threshold voltage of laterally diffused MOS transistors. A clear analysis of the device physics is performed, highlighting the correlation between the change of the electron charge distribution along the channel and the device capacitance variations when the gate voltage is swept. Using numerical simulations, it is shown that the peak of the gate-to-drain capacitance is related to the transition of the surface from weak to moderate inversion in the intrinsic MOS transistor at the location of the maximum doping concentration, which corresponds to the threshold voltage of the device according to the MOS theory. Comparison between conventional I/sub D///spl radic/g/sub m/ extraction and the new proposed capacitance peak method is performed on both technology computer-aided design simulations and measurements in order to confirm the new experimental technique and related theory.