Abstract: The paper presents the synthesis of newly eco-resin based on coconut oil for superhydrophobic coating. Superhydrophobicity of the coating provide a self-cleaning or water-repellent characteristic that prevents peeling, thereby extend the life expectancy of the coating. The use of newly synthesized eco-resin offer a sustainable, eco-friendly and cost effective source of nature. The synthesis and formulation of different percentages of coconut oil which is 20, 40, 60 and 80 weight by weight percentage (wt/wt%) consists of three phases to form superhydrophobic coating. The first phase involved alcoholysis step, condensation step and third phase purification through alcoholysis. The adhesion test (ASTM D3359-03) results was obtained the highest classification grading of 5B for coating at 80% (wt/wt) of coconut oil with 9 layer whereas the rate of adhesion is 9.87% of the area affected. It is shows that the small flakes of coating are detached at intersections. Scratch resistance test was evaluated in terms of pencil hardness grade, which is increased from grade HB to 6H and there is minor scratch occurs for 9 layer coating. The water droplet test was demonstrated that the advancing water contact angle up to 60% of coconut oil at 169.22o with the smooth surface roughness at 0.2448 μm.
Abstract: The scope of this study is to optimize the electrostatic solid lubricant coating deposition process parameters such as electric potential, solid lubricant feed pressure and distance between the nozzle tip to metal substrate on its average surface roughness of the coatings. Statistical design approach was used to plan and confirm the experimental investigation. In addition, tribological performance of coatings is assessed through pin-on-disc tests under dry sliding conditions. Results demonstrate that the electric potential has the most significant effect on the roughness of coatings. Electrostatic solid lubricant coatings works quite satisfactorily in dry sliding conditions and can endow in making sliding process more environmental friendly.
Abstract: In order to clarify the effectiveness of the multi-layer AlCrWN/AlCrWSiN-coated cemented carbide tool, the wear progress was investigated in cutting hardened sintered steel using three types of coated tool. Namely, Tool I had the dual-layer (Al60,Cr25,W15)(C,N)/(Al53,Cr23,W14,Si10)(C,N)-coating film, Tool II had the multi-layer (Al60,Cr25,W15)(C,N)/(Al53,Cr23,W14,Si10)(C,N)-coating film and Tool III had the multi-layer (Al60,Cr25,W15)N/(Al53,Cr23,W14,Si10)N-coating film. The following results were obtained: (1) The main tool failure of the three types of coated tools were the flank wear within the maximum value of the flank wear width of 0.2 mm. (2) The critical scratch load of the three types of coated tools was 130 N or more. (3) The micro-hardness of Tool III 3000 HV0.25N was the highest among the three types of coated tools. (4) The mean value of the friction coefficient of the (Al53,Cr23,W14,Si10)N coating film, 0.21, was approximately half that of the (Al53,Cr23,W14,Si10)(C,N) coating film, 0.41. (5) In the case of the higher cutting speed, the wear progress of the multi-layer coating system was slower than that of the dual-layer coating system. (6) In the case of the cutting hardened sintered steel using the multi-layer coated tool, the wear progress of the Type III coated tool was slower than that of the Type II coated tool.
Abstract: Titanium dioxide (TiO2) is one of the most well known photocatalytic materials. However, TiO2 is only photoactive to ultraviolet (UV) light, and the lifetime of the electron-hole pair recombination is too short. In this work, TiO2 anatase nanotubes with an energy band gap of 3.01 eV and specific surface area of 112.46 m2/g were synthesized via hydrothermal method. The results showed that, by incorporating graphene oxide (XGO) and reduced graphene oxide (RGO), the photodegradation efficiency could be enhanced by increasing electron lifetime and charge carrier separation, as well as narrowing the energy band gap. The examination of photodegradation activity under UVC irradiation indicated that a maximum photodegradation efficiency was achieved with TiO2-XGO nanocomposite due to its high specific surface area and strong hydrophilic property.
Abstract: Nanostructured materials are a new class of materials which provide one of the greatest potentials for improving performance and extended capabilities of products in a number of applications. In particular nanostructured TiO2 was used as photocatalysts, gas sensor, solar cells and nanocomposite biomaterials. For each of these applications, aspects such as surface morphology, crystallinity and chemistry of the titania-based materials are the key parameters to be settled for the process optimization. A series of nanostructured TiO2 materials (TiO2 nanotubes, TiO2 nanorods, TiO2 nanoparticles) was synthesized using simple hydrothermal methods. X-Ray Diffraction (XRD), Field Emission Scanning Electron microscope (FESEM) and Brunauer–Emmett–Teller (BET) surface area characterization was carried out to study the properties of synthesized nanostructured TiO2 materials. The performance of synthesized nanostructured TiO2 was evaluated for various applications such as photocatalyst for methyl orange (MO) degradation and anti-bacterial thin film for biomedical and food packaging. Among the nanostructured TiO2 materials, TiO2 nanotubes shows the highest activity regardless of their applications. This is probably due to their nanotubular morphology in which provided high surface area materials. The surface area of TiO2 nanotubes was found to be 226.52 m2/g. The outer and inner diameters of nanotubes are 4 nm and 10 nm, respectively with several hundred nanometers in length. Anatase TiO2 phase structure and crystallinity of TiO2 nanotubes supports the good performances of the nanostructured materials.
Abstract: Metal nanoparticles (MNPs) induced light absorption enhancement using for the improvement of power conversion efficiency of organic solar cells (OSCs) is a new research direction in photovoltaics. However, the device performance influence of the shape and size of MNPs has not been well investigated. In this paper, we focused on the comparison study of the optical absorption enhancement between silver nanospheres (Ag-NSs) and silver nanocubes (Ag-NCs) which are embedded in the active layer of OSCs using finite element method (FEM) simulation. Influence of the structural parameters, including the size and shape of nanoparticels, and their relative distance are systematically discussed. The results indicated that the light absorption enhancement employing Ag-NCs is much higher than that of Ag-NSs in the 300–800 nm wavelength range. Meantime, once the distance between the adjacent nanoparticles is well controlled, the optimal absorption enhancement factor of OSCs can be obtained. As the scattering cross-section of Ag-NCs is much higher than that of Ag-NSs over a broad wavelength range, the optimized light enhancement of Ag-NCs reaches 19 % which is 1.26 times higher than that of Ag-NSs.
Abstract: Nano particle of N-doped TiO2 with the size of 21.42 nm was successfully created using sonochemical method. Concentration of Nitrogen (N) doping on TiO2 was calculated using mole ratio of Urea and TTiP. Doping variations were performed by doping 5% to 9% N, and did not change the crystallite size and strain. The nanoparticle produced has a polycrystalline structure with a dominant diffraction peak (101). Doping N into TiO2 affects the morphology of particle surface, thus tending to shrink. Results of photo catalysis on liquid samples of MB 20 ppm dye indicate that the addition of N improves the degradation ability of TiO2, with the highest value on sample T5 of 85% and with a rate of degradation kinetics of 0.024 ppm/minute.
Abstract: Hematite (Fe2O3) nanostructures were successfully grown on the surface of iron foil by simple thermal oxidation in air. The iron foil was heated at 300 – 700 °C for 8 h to produce Fe2O3 nanosheets and nanowires. The oxide layer is primarily composed of Fe2O3 with a small amount of magnetite (Fe3O4) and wustite (FeO). The photocatalytic activity of the Fe2O3 nanowires was investigated by degradation of methyl orange dye under 30 W UV light in the presence of a minute amount of hydrogen peroxide. The Fe2O3 nanowires exhibit excellent photocatalytic activity, wherein 2.5 ppm of the methyl orange was fully decomposed in 30 min.
Abstract: Spherical cupric oxide (CuO) was grown on copper (Cu) foil by a facile, low-temperature chemical bath deposition (CBD) under alkaline conditions. This method enables direct contact between the active materials and the cathode which is advantageous for attaining higher capacitance. The Cu products were spherical in shape and have a uniform morphology due to self-assembly and Ostwald ripening. The fabricated CuO exhibit a specific capacitance in the range of 700–800 F/cm2.
Abstract: Glass fiber reinforced unsaturated polyesters were prepared by hand lay-up technique. Effect of clay conditions and loading, as well as mixing time on tensile modulus, flammability, and wear resistance were evaluated. In general, the results showed that there might be two possible structures, dispersed and agglomerated, in the composite samples. The modulus results showed that the effect of clay drying, as well as higher filler loading increase the property. In contrast, the mixing time resulted in negative effect on modulus. The improvement on modulus and flammability might be influenced by clay dispersion due to shear and viscosity change, while the decrease on modulus and wear resistance might be caused by agglomerated structures due to lubrication effect of moisture content, and less crosslink point caused by styrene evaporation.