Applied Mechanics and Materials Vols. 754-755

Abstract: In this work, ZnO nanoporous thin films were formed by anodizing of Zn plates in 500 ml distilled water of 25°C at voltage ranged from 10 V to 30 V. As anodized zinc plates were characterized by using SEM and XRD. Characterization of as anodized Zn plates using SEM showed that the morphology of the as anodized Zn plates were significantly influenced by the anodizing voltages. Nanoporous ZnO thin films were formed when 25 V and 30 V were used while ZnO thin films without nanoporous structures were formed when 10 V, 15 V and 20 V were used. XRD analysis indicated the ZnO thin films formed at 10 V to 30 V were of hexagonal wurtzite structures.

Abstract: In this work, the effect of temperature of distilled water on the morphology of ZnO nanoporous thin films formed by anodizing was studied. ZnO nanoporous thin films were formed by anodizing of Zn plates at voltage 30 V in 500 ml distilled water of temperature ranged from 5 °C to 25°C. As anodized zinc plates were characterized by using SEM and XRD. Characterization of as anodized Zn plates using SEM showed that the morphologies of the as anodized Zn plates were significantly influenced by the temperature of distilled water. Nanoporous ZnO thin films were formed when 15 °C to 25 °C were used while ZnO thin films without nanoporous structures were formed when 5°C and 10 °C were used. XRD analysis indicated the ZnO thin films formed in distilled water of 5 °C to 25°C were of hexagonal wurtzite structures.

Abstract: In the case of cutting tools, the temperature of both the cutting tool and the part are decreased during the machining process by the use of cutting fluids, which are expensive, can be toxic and produce a significant waste stream. Coatings for cutting tools can be an effective approach to solve this problem. This paper will present a developed technology by a group of researchers from “Transilvania” University of Brașov, through which the copper`s surface will be nanostructurated at a nanometric scale in such a manner, for creating nodular structures. This technology is simple, easy for implementation, not so expensive and it`s results are proper for cutting tools coatings usage.

Abstract: Cuprous oxide (Cu₂O) thin films were formed onto indium tin oxide (ITO) coated glass substrate by sol-gel spin coating technique using different additives namely polyethylene glycol and ethylene glycol. It was found that the organic additives added had an important influenced on the formation mechanism of Cu₂O films and lead to different microstructures and optical properties. The films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and ultraviolet-visible spectroscopy (UV-Vis). Based on the FESEM micrographs the grain size of film prepared by polyethylene glycol has smallest grain of about 83 nm with irregular shape. The highest optical absorbance film was obtained by the addition of polyethylene glycol.

Abstract: Langmuir-Blodgett technique was applied to build optically homogeneous film of functionalized multi-walled carbon nanotubes (MWCNTs) on paper substrate. The palladium (Pd) nanoparticles were drop-casted onto MWCNTs network films before being exposed in hydrogen (H₂) gas molecules environment under vacuum and atmospheric pressure at room temperature. The results demonstrate that the functionalized MWCNTs dispersed with Pd nanoparticles show good H₂ sensing response on paper substrate where the sensitivity of around 10 % was recorded at only 2 minutes exposure time.

Abstract: The commercial potential of the 60 GHz band, in combination with the scaling growth of graphene nanotechnology, has resulted in a lot of digital graphene circuits for millimeter-wave application. This work presents a 0.345 nm monolayer graphene film on substrates SiO₂/Teflon/Copper as a new nanoantenna. The nanoantenna achieves 2.003 of maximum gain (Abs) with particularly the graphene sheet resistance and reactance as the key variables. The presented nanoantenna targets 52 GHz communication where beamforming is required.

Abstract: Functionalized of Multi Wall Carbon Nanotubes (MWCNTs) were demonstrated using the nitric acid (HNO₃) oxidation technique in order to get opened caps, removing carbonaceous and metal particles impurities for carboxylic groups (-COOH). The surface morphology and the existence of the carboxyl-group on the MWCNTs were examined using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM), respectively. The carboxylic groups were observed at the peak of 1640.40cm^-1 via FTIR and indicate the absorbance intensity of the functionalized MWCNTs is 2.22 A which is higher than raw material. Furthermore, SEM image shows the bundle of structure on the raw MWCNTs signified the Van der Waals interaction between MWCNTs while after functionalized a groovy CNTs wall were observed due to presence of carboxyl group at the defect sites.

Abstract: This article is an overview of potential applications of nanoemulsion as a promising candidates for enhanced oil recovery (EOR) and as a medium for wellbore cleaning. Nanoemulsion is an emulsion that has nanosize particle distributions in the range of below 500 nm. It also has lower interfacial tension (IFT) as low as the value of 0.001 mN/m. The small particle size distributions in nanoemulsion resulted the good properties of nanoemulsion in term of large surface area. This excellent property will improve the sweeping efficiency of the oil droplet in the reservoir and finally increase the oil recovery. Besides that, the unique features possess by nanoemulsion make it suitable as superior wellbore cleaner as compared to conventional detergent-based cleaner. Thus, the significance of nanoemulsion becomes the major highlight in oil and gas industry. This overview on nanoemulsion applications is imperative and necessary in order to provide an insight for the future development and perhaps open a door to extend the applications of nanoemulsion to other more challenging areas.

Abstract: Nanocrystalline material of ferrites with composition Ni_0.5Zn_0.35Cu_0.15Fe₂O₄ was successfully synthesized by sol-gel method. This paper investigates nanostructure and magnetic properties of nanocrystaline material Ni_0.5Zn_0.35Cu_0.15Fe₂O_4. Crystallite size, intensity,d-spacing and lattice parameters of material were investigated by using X-Ray diffractometer (XRD). While nanostructure, size, shape, surface morphology and topography of Ni_0.5Zn_0.35Cu_0.15Fe₂O₄ were examined by variable pressure field emission scanning electron microscope (VP-FESEM) SUPRA 55VP. Magnetic properties was investigated using vibrating sample magnetometer (VSM). According to thermo gravimetric analysis (TGA) result, it was found that after temperature 600^oC there is no more weight loss detected and it was considered as minimum calcination temperature. XRD result shows that the samples is in single-phase cubic spinel structure. Crystallite size of the material is in range of 42.3-163.7nm. Highest intensity was 88.89 arb.units at highest calcination temperature 900^oC. The value of d-spacing and FWHM decrease with increasing calcination temperature. Lattice paramenters decrease in the range of 8.4040-8.2458^oA. VP-FESEM analysis shows that grain size increase by increasing calcination temperature. Grain size of the material is in the range of 47.6-506.9nm with cubic structure of the Ni_0.5Zn_0.35Cu_0.15Fe₂O_4. VSM result shows that the highest value of magnetic saturation was at 152.8emu/g. The best value of coercive force (Hc) was in 31.8Oe and magnetic remanence (Mr) was in 2.6emu/g.

Abstract: In this paper we present fabrication and experimental results to the field of dye-sensitized solar cells, more particularly relates to Syzygium cumini fruit dyes as sensitizers. A dyes molecule from Syzygium cumini fruit adsorbs to each particle of the titanium dioxide. A dyes molecules act as absorbance of the visible light. Simultaneously, titanium dioxide plays a role as griping and absorbs place for natural dye molecules. Thus, an important component for overall performance in term of efficiency for dye-sensitized solar cells is the photogeneration from the absorbed dye in titanium dioxide. The dye-sensitized solar cells fabricated with the extract of Syzygium cumini fruit dye produced fill factor of 0.317 and conversion efficiency of 2.0 %.