Marina Stipetic
Abstract
According to the European Commission's plan, greenhouse gas emissions in the European Union must be reduced by 80% compared to the level from year 1990 (see [1]). In order to reduce the energy consumption of the buildings, an optimization of the building insulation is an effective measure. Super-insulating ...
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According to the European Commission's plan, greenhouse gas emissions in the European Union must be reduced by 80% compared to the level from year 1990 (see [1]). In order to reduce the energy consumption of the buildings, an optimization of the building insulation is an effective measure. Super-insulating materials are promising materials to fulfil these objectives. Present work describes development of advanced aerogel-based composite material with small thickness. Such composite materials based on silica aerogel can be extremely efficient with regard to their thermal insulation properties. In this study, the experimental investigations of hydrothermal and mechanical performance were conducted on the aerogel-based insulation blanket and its constituents (core material and aerogel granules). Furthermore, the effect of ageing to performance of such material is assessed. The developed aerogel-based insulation material is characterized by very low thermal conductivity (under 18.0 mW/(m·K)) and good hydrothermal properties. It has been shown here that the thermal conductivity of an insulating material made of glass fibre can be reduced to more than half with using of aerogel granules. This aerogel-based composite material is characterized by good hydric properties. The material is both hydrophobic and water vapor permeable. In addition, mechanical properties of new composite material fulfil the multifunctional application of this promising insulating material. New product can be used for external thermal insulation system (ETICS) as well as for internal thermal insulation system.
S. N. Sarangi; V. Siva; B. K. Padhi; P. K. Sahoo
Abstract
We report the fabrication and characterization of photosensitive heterostructure device using pure and Cu doped ZnO nanorods on n-Si substrate using a low cost hydrothermal technique. Special techniques like Rutherford backscattering spectroscopy and Proton Induced X-ray emission (PIXE) were used to ...
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We report the fabrication and characterization of photosensitive heterostructure device using pure and Cu doped ZnO nanorods on n-Si substrate using a low cost hydrothermal technique. Special techniques like Rutherford backscattering spectroscopy and Proton Induced X-ray emission (PIXE) were used to confirm the doping of Cu in ZnO nanorods. The PIXE measurements confirm the absence of any foreign element in parts per million level, except pure Cu doping in ZnO. The compressive stress in (002) peak develops after Cu doping is indicating the successful substitution of Cu +2 ions into Zn +2 lattice sites. The I-V measurement of 5% Cu doped ZnO device shows five orders of magnitude increase in current flow compared to 1% Cu doping. Under ultraviolet (UV) light exposure further enhancement of the photocurrent in the devices has been observed, which demonstrates the capability of Cu doped ZnO nanorods as a potential UV photodetector.
Laxmi J. Tomar; B.S. Chakrabarty
Abstract
A series of TiO2-ZrO2 mixed oxide samples with various ZrO2-TiO2 content (10, 30, 40, 60, 70 and 90 mol %) were prepared by hydrothermal method. These nanocomposites were characterized by XRD, SEM, UV-vis spectroscopy and Photoluminescence spectroscopy. XRD data identified Anatase and Rutile phases in ...
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A series of TiO2-ZrO2 mixed oxide samples with various ZrO2-TiO2 content (10, 30, 40, 60, 70 and 90 mol %) were prepared by hydrothermal method. These nanocomposites were characterized by XRD, SEM, UV-vis spectroscopy and Photoluminescence spectroscopy. XRD data identified Anatase and Rutile phases in the TiO2 rich samples while Tetragonal and Monoclinic phases in ZrO2 rich samples. The average crystallite size of the samples was between 9 to 26 nm. As per Uv-Vis spectra, the band gaps of TiO2-ZrO2 composites vary from 1.34 eV to 2.48 eV. The absorption spectra show a shift of the absorption edge of TiO2-ZrO2 towards longer wavelength region. The decreased band gap is attributed to the surface trap states. The PL spectrum shows very strong blue-green PL band under excitation at 300 nm. The occurrence of emission peaks in the visible region is attributed to the presence of defect levels below the conduction band.