Search

Nanofluids have a great attention because it has an enormous potential to improve the efficiency of heat transfer systems owing to its high thermal conductivity. In this work, iron oxide nanoparticles were synthesized using cost-effective chemical method. The nanostructured iron oxide powder were characterized by various techniques viz., X- ray diffraction (XRD), Scanning Electron Microscope (SEM) etc. The iron oxide based nanofluids of different concentrations in the range 0.02%, to 1.8% were prepared. The size of nanoparticles used was in the range 20-50 nm. A comprehensive correlation of ultrasonic velocity and thermal conductivity is proposed based on experimental observations. The effect of concentration on ultrasonic velocity, compressibility and on thermal conductivity was studied. Such approach can be useful in studying the relationship between various properties of nanofluids such as ultrasonic velocity, thermal conductivity, electrical conductivity, compressibility etc. [ABSTRACT FROM AUTHOR]

In this work, we present the synthesis and characterization of nanoparticles suitable for semiconductor applications using a simple and economical sol-gel process. ZnO-CuO is the potential material because of its high thermal stability and low cost. Properties of the ZnO-CuO nanocomposites are size dependent and when the particle size is reduced to the nanometer scales it shows some novel properties. Sol-Gel method is a good method to synthesis ultrafine metallic oxide nanocomposites and has been widely used for preparing nanoparticles at very low temperatures. Nano- structured ZnO-CuO has been characterized by using various techniques like XRD, SEM, and DSC-TGA. The phase transformation was investigated by an X-ray diffractometer (XRD). The microstructure was characterized by a scanning electron microscope (SEM). DSC-TGA analysis was used to investigate the thermal properties of the material. [ABSTRACT FROM AUTHOR]

The SEM photographs on HITACHI S-4700 FE-SEM for Composite Solid Electrolytes 0.25Ba(NO3)2-0.75KNO3, 0.19Ba(NO3)2-0.81KNO3, 0.05Ba(NO3)2-0.95KNO3 and DSC (DSC-60-SHIMADZU)plots of Ba(NO3)2, KNO3 and their composites systems of 0.62Ba(NO3)2-0.38KNO3, 0.37Ba(NO3)2-0.63KNO3, 0.25Ba(NO3)2-0.75KNO3, 0.19Ba(NO3)2-0.81KNO3, 0.05Ba(NO3)2-0.95KNO3 mole percentages have been studied to understand the reason behind the enhancement of conductivity in these materials. Uniform distribution of particle size can be noticed in 0.25Ba (NO3)2-0.75KNO3, 0.19Ba (NO3)2-0.81 KNO3 comparing to other mole percentages. In 0.19Ba (NO3)2-0.81KNO3 particle size is found to be uniform and larger compared to other mole percentages, which would effectively reduce the grain boundary resistance and thus increases the conductivity [1]. The enhancement of conductivity in this system was explained as due to the increased concentration of defects in space charge region formed between the host and nano particles of dispersoid. [ABSTRACT FROM AUTHOR]

The present research work, First principles calculations have proven to be outstanding tools to laboratory experiments in research because they can calculate some characteristics of a modeled system that are very hard to obtain experimentally. First principles calculations (CASTUP) also offer far greater ability to control and manipulate a system, providing the modeled system reflects the real system accurately. calculations and their applications in the research of positive electrode materials were studied. An economical and novel method for synthesis of Nano porous LiFePO4/C composite by glycine and urea assisted combustion method with fuel to oxidizer ratio Ψ =1. The average crystallite size of obtained LiFePo4/C composite from x- ray diffraction is 40-45nm. Morphological studies were done using scanning electron microscope the structure of the surface coated carbon and the material were investigated by Raman spectroscopy. The structure of the material at the molecular size scale has been investigated by FTIR transmittance and Thermal Analysis and stoichiometry analysis for Fuel to nitrate ratio for urea and glycine and for various molarities and there balancing equations and calculation for Enthalpy of combustion and adiabatic flame temperature results were presen [ABSTRACT FROM AUTHOR]

Eu3+ and Tb3+ - activated Ba2SiO4 phosphors have been synthesized by using high temperature conventional solid state reaction method. All synthesized phosphors are characterized by X-ray Diffraction (XRD), Energy Dispersive Spectroscopy (EDS), Scanning Electron Microscope (SEM), Fourier-Transform Infrared Spectroscopy (FTIR) and Photoluminescence Techniques (PL). The X-ray diffraction patterns of the sample are indexed as orthorhombic structure. Elements are present in the composition are Ba, Si, O, Eu and Tb as confirmed from EDS. In the photoluminescence studies, Ba2SiO4: Eu3+ phosphor exhibits strong emission peak at 611 nm and Ba2SiO4: Tb3+ phosphor exhibits high intense emission peak at 546 nm under UV excitations. These peaks may be attributed to the transition 5D0 → 7F2 of Eu3+ ions and transition 5D4 → 7F5 of Tb3+ ions. The intensity of intense peaks are increasing with Eu3+ concentration increases as well as the high intense emission peak is moderated from blue region to green region with Tb3+ concentration increases. The CIE (Commission International de I'Eclairage) color chromaticity diagram confirms that the synthesized phosphors are emitting red and green color. Based on these results, these phosphors may be useful as red and green phosphors in the lamp as well as in the display devices. [ABSTRACT FROM AUTHOR]

Crystals of SnSe and SnSe doped with Cu have been synthesized by a direct vapour transport technique. The grown crystals have shiny faces and they do not suffer from the contamination of the transporting agent. The characterization of the crystals has been done by using the techniques of X-ray diffraction, Energy dispersive analysis of X-rays (EDAX), Scanning electron microscope (SEM), Transmission electron microscope (TEM) and electron diffraction. An estimation of crystallite size, dislocation density and lattice strain has been made. In order to understand the mechanism of growth of the crystals, scanning electron microscope and transmission electron microscope have been employed. The crystallinity of the grown crystals has been confirmed by electron diffraction pattern. The implications of the results have been discussed. [ABSTRACT FROM AUTHOR]