ZnO nanostructures were deposited on GaN (0001), Al2O3 (0001), and Si (100) substrates using a high-pressure pulsed laser deposition (PLD) method. Vertically aligned hexagonal-pyramidal ZnO nanorods were obtained on the Al2O3 and Si substrates whereas interlinked ZnO nanowalls were obtained on the GaN substrates. A growth mechanism has been proposed for the formation of ZnO nanowalls based on different growth rates of ZnO polar and nonpolar planes. Both ZnO nanorods and nanowalls exhibit a strong E2H vibration mode in the micro-Raman spectra. The corresponding fluorescence spectra of ZnO nanorods and nanowalls showed near band emission at 3.28 eV. The ZnO nanorods grown on the Si substrates exhibited better crystalline and optical properties compared with the ZnO structures grown on the GaN and Al2O3 substrates. The high aspect ratio, good vertical alignment, and better crystallinity of the ZnO nanorods with tapered tips exhibited promising field emission performance with a low turn-on field of 2 V/μm, a high current density of 7.7 mA/cm2, and a large field enhancement factor.

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SnO 2 was synthesized by precipitation from an aqueous solution of SnCl 4 and NH 4 OH, followed by a heat treatment. The product was characterized by XRD, SEM, FTIR spectroscopy, DSC and TG. The XRD patterns suggest the formation of phase-pure cassiterite form of SnO 2 . SEM imaging indicates that the particles obtained are of sub-micron size with good morphology and size control (around $300 nm). Electrodes were fabricated by a slurry-coating procedure and the electrochemical performances of these electrodes were evaluated using galvanostatic cycling tests. The results suggest that the heat treated SnO 2 samples deliver higher capacities when cycled between 1.0 and 0.1 V vs. Li + /Li and showed coulombic efficiencies of more than 98% in the tenth cycle.

This data article presents the experimental values pertaining to the bio-oil extraction, optimizing biodiesel production and formulation of emulsified fuel blends of E.tereticornisis bio-oil for its use in compression ignition engine. The E.tereticornisis leaves were collected from the interior region of Puducherry, India. Soxhlet extraction process, in the presence of n-hexane, yielded 5.2% of bio-oil. Based on the free fatty acid content, base catalysed transesterification process was adopted along with use of sodium hydroxide and methanol. Optimization of biodiesel yield was carried out by varying the operating parameters. A biodiesel yield of 74.19% was obtained at eighty minutes reaction duration, 1.8 l/g ms of sodium hydroxide, 70 °C reaction temperature and 8:1 oil to molar ratio. Furthermore, the physiochemical properties improved by emulsifying the obtained biodiesel with 5% of water in presence of surfactant through experiments carried out based on Taguchi׳s DOE method.

A sulfur-Polyacrylonitrile (PAN)-acetylene black (AB) composite was synthesized via thermal treatment processes. The as-prepared ternary composite was characterized by expending transmission electron microscopy (TEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) and electrochemical investigations. The improved electrochemical performance can be attributed to the formation of PAN layer, which can keep a tight contact between carbon and sulfur which leads to improve the conductivity. Moreover, the PAN can also act as a flexible cushion to accommodate volume changes of sulfur cathode as well as a barrier to trap soluble polysulfide intermediates during the charge-discharge process. The PAN-S-AB composite exhibits discharge capacity of 620 mAh/g even after 50 cycles with appreciable sustainability. Therefore, the resulting PAN/S/AB composite exhibited as a desirable cathode material for Li-S battery with great performance.

Purpose Nanofluid exhibits higher density, higher viscosity, higher thermal conductivity and reduced specific heat capacity along with improved heat transfer characteristics. It is comparatively better than conventional fluids in terms of thermo-physical properties. This paper aims to investigate experimentally the overall performance of the shell and tube heat exchanger operated under two different configurations – without baffles (STHX_1) and with baffles (STHX_2) using 0.01 Vol.% and 0.02 Vol.% of CuO-W nanofluid. Design/methodology/approach Two different configurations, one without baffles (STHX_1) and other with single segmental baffles (STHX_2), are chosen with all other dimensional details of shell and tube remaining same. Water is used as base fluid. CuO nanoparticle is chosen, as its thermal conductivity is higher compared to other metal oxides. A comparative study on the thermal performance of these shell and tube heat exchangers are performed by considering different Vol.% concentrations of CuO-W nanofluid and the outcome are compared with the base fluid (i.e., water). The influence of varying the mass flow rate of the tube side fluid by keeping shell side fluid mass flow rate as constant and vice versa on the thermal performance of shell and tube heat exchanger are studied. Findings The modified shell and tube heat exchanger with baffles (STHX_2) give an improved performance. The heat transfer coefficient improved by about 11.28 and 7.54 per cent for 0.02 and 0.01 Vol.% of CuO-W nanofluid compared to water. Overall heat transfer coefficient for STHX_2 enhanced between 118.26% to 123.06% in comparison with base fluid for 0.02 Vol.% of CuO-W nanofluid whereas, it improved between 79.20% to 87.51% for 0.01 Vol.% of CuO-W nanofluid. Similarly, the actual heat transfer enhanced between 71.79% to 77.77% and between 48.71% to 55.55% for 0.02 and 0.01 Vol.% of CuO-W nanofluid, respectively. Moreover, mass flow rates of the working fluids significantly influence the performance of the shell and tube heat exchanger. Originality/value Two cases are considered here. first, by varying the shell side fluid mass flow rate and keeping the tube side fluid mass flow rate as constant. Later, tube side fluid mass flow rates are varied and shell side fluid mass flow rate is kept constant. It is found that in Case 2, for both 0.01 and 0.02 Vol.% of CuO-W nanofluid, highest performance is obtained for 150 kg/h of shell side and tube side fluid flows involving STHX_2. Finally, the modified shell and tube heat exchanger with baffle arrangement gives the best performance by using 0.02 Vol.% of CuO-W nanofluid.

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S-shaped blade profiles with double camber find use in fully reversible turbomachines that can extract power from tides. Though noncavitating characteristics of S-blades were determined in the past, yet characterizing cavitating flow was not carried out. This work, which is the first step in this direction, uses a two-pronged approach of experimental and numerical characterization of cavitating flow past these hydrofoils. Experimental results indicate that as the angle of attack increases in either positive or negative directions, cavitation inception number increases. Minimum cavitation effect is observed at 2 deg, which is zero lift angle of attack. For higher angles of attack (±6deg, ±4deg) and moderate or low cavitation number (σ/σi≤0.3), unsteady cloud cavitation was characterized through visual observation and from pressure fluctuation data. It was observed that for unsteady cavity shedding to take place is the length and thickness of the cavity should be more than 50% and 10% of the chord length, respectively. Predicting flow past this geometry is difficult and the problem may be compounded in many applications because of laminar-to-turbulence transition as well as due to the presence of cavitation. Present simulations indicate that the k-kL-ω transition model may be useful in predicting hydrodynamic performance of this type of geometry and for the range of Reynolds number considered in this paper. Hydrodynamic performance under cavitation indicates that pumping mode is more adversely affected by cavitation and, hence, a fully reversible turbomachine may not perform equally well in turbine and pump modes as expected from noncavitating results.