Investigations on the absorption spectrum of TiO2 nanofluid

Nanofluids are tailored nano- colloidal suspensions of nanoparticles in a suitable base fluid. This present work investigates the absorption spectrum in TiO2-water nanofluids to identify the potential application of nanofluids in Direct Absorption Solar Collectors (DASC). Nanoparticles of Titanium dioxide (TiO2) are prepared by sol gel and characterized by X Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). TiO2-water nanofluids with weight fraction of 0.1% are prepared by a two-step process with sonication. The prepared nanofluids are investigated for their stability by a gravity sedimentation method and for their optical property by UV-Vis spectroscopy. Stability of nanofluid is essential for the applications of nanofluid in DASC. TiO2 nanoparticles with a crystallite size of 43nm are obtained .The SEM image reveals the agglomerated state of TiO2 nanoparticles and the stability of TiO2 nanofluid is reported as 9-10days. UV results indicate the decrease in absorption from 440-500nm, complete absorption from 500-700nm and increase in absorption from 700-900nm.TiO2 nanofluids are recommended as potential candidates for DASC in UV and IR regions

The factorial structure of the supervisor’s core competencies scale

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Voltammetric studies of the reduction of furfural on glassy carbon electrode in aqueous solutions

The electrochemical reduction of furfural is studied on glassy carbon electrode in aqueous buffer solutions using voltammetric technique. Tafel slope obtained from steady state voltammetry is pH dependent. Cyclic voltammetric data have shown that a single wave is formed in acidic and alkaline pH and two waves are formed at neutral pH particularly at higher concentration and the overall reduction process is a kinetically controlled irreversible proces

Facile microwave-assisted synthesis of titanium dioxide decorated graphene nanocomposite for photodegradation of organic dyes

An efficient and facile method was adopted to prepare TiO2-graphene (TG) nanocomposites with TiO2 nanoparticles uniformly distributed on graphene. By adjusting the amount of TiO2 precursor, both high and low dense TiO2 nanoparticles on graphene were effectively attained via electrostatic attraction between graphene oxide sheets and TiO2 nanoparticles. The prepared nanocomposites were characterized by various characterization techniques. The TG nanocomposite showed an excellent activity for the photodegradation of the organic dyes such as methylene blue (MB) and rose bengal (RB) under ultra violet (UV) light irradiation. The TG nanocomposite of TG 2.5 showed better photocatalytic performance than bare TiO2 nanoparticles and other composites. The enhanced activity of the composite material is attributed to the reduction in charge recombination and interaction of organic dyes with graphene. The decrease in charge recombination was evidenced from the photoluminescence (PL) spectra. The observed results suggest that the synthesized TG composites have a potential application to treat the industrial effluents, which contain organic dyes

Divalent europium-activated alkaline-earth-metal chlorophosphate luminophores [M5(PO4)3Cl:Eu2+;M=Ca,Sr,Ba] by self-propagating high-temperature synthesis

Divalent europium-activated alkaline-earth-metal chlorophosphate luminophores (MCAP:Eu2+;M=Ca,Sr,Ba) have been prepared by self-propagating high-temperature (SPHT) synthesis in one pol employing the corresponding nitrates/chlorides, urea and diammonium hydrogen phosphate. The synthesized materials have been characterized by X-ray diffraction, photoluminescent emission spectroscopy, thermogravimetry, scanning electron microscopy and particle size analysis. The formation of chloroapatite depends on the nature of acid used in the combustion mixture. The photoluminescent emission efficiency and particle size distribution are found to depend on the amount of metal chloride used and on the sintering temperature. The results obtained are discussed with respect to the processing method employe

Photoconductive studies on electron beam evaporated CdSe films

Thin CdSe films were electron beam evaporated. The CdSe powder synthesized in thel aboratory by a chemical method was used as source for the deposition of films. Clean glass and titanium substrates were used as substrates. The substrate temperature was varied in the range of 30–250 1C. X-ray diffraction studies indicated polycrystalline hexagonal structure. The band gap was 1.65eV. The grain size was15–30nm with increase of substrate temperature. Photoconductive cells fabricated with the doped and undoped films have exhibited high photosensitivity and high signal to noiseratio. The current voltage characteristics were linear

Assessment of the design efficacy of Eu2+ ion embedded thick scattering layers for operational photovoltaics

A state-of-the-art encapsulation technique for evaluating a photovoltaic device in laboratory is needed for replicating real-time devices. In this context, earlier we proposed the pouch lamination as a cost-effective and reproducible lab-scale encapsulation technique. In this work, we apply this technique in evaluating the optical and electrical performances of a mc-Si device with a front spectral shifting layer before and after encpasulation. Our coating contains the red-emitting nitride phosphor CaAlSiN3:Eu2+ (CASN:Eu2+) in (poly)-methyl methacrylate (PMMA). On coating, a drastic reduction in the device's reflectance was observed below 450 nm. Correspondingly, the external and internal quantum efficiencies of the devices are also improved relative to the bare. When irradiated by an AM1.5G source, the electrical parameters remain of the device remain unaffectd after the coating. However, on encapsulating the coated device, impedance losses drastically reduce its conversion efficiency. This paper thus reveals the need for including an encapsulant while demonstrating device modifications through optical coatings