Advanced Materials Research Vol. 979

Abstract: The aim of this work investigated the antibacterial properties of oxide compound from agricultural waste material. The oxide compounds were prepared by annealed the agricultural waste material upon consequence of temperature. After that, the crystalline structure, morphology, chemical composition and estimation of oxide compound were conducted by X-Ray Diffraction (XRD), Energy Dispersive X-Ray Fluorescence (EDXRF) and Fourier Transform Infrared Spectroscopy (FTIR). It was observed that the XRD patterns demonstrated the lime phase and cristobalite phase after heat treatment. Another that, the result from EDXRF and FTIR was in good agreement with the result of XRD. For anti-bacterial efficacy were utilized the lime phase and cristobalite phase for testing antibacterial activities which the agar diffusion technique. It was found that the inhibition zones were clearly visible for both agents, found to exhibit antibacterial action against Escherichia coli.

Abstract: Single point incremental forming (SPIF) process is the latest sheet metal forming technique, which developed in the around 1990, this process could generates a local strain on a sheet metal by mean of small rotation forming tool travel follow CNC toolpath on sheet metal blank to form a shell part. The incredible elongating without failure occurs is the main advantage of this process. This paper attempt to explain the deformation mechanism of steel sheet that formed by SPIF in the metallurgical views. The different degree of deformation were investigated by optical microscope, the grain size deformation was used as a data for math modeling of the deformation mechanism.

Abstract: The single point incremental forming process (SPIF) are suited for sheet metal prototyping, because it is a low cost production process that produces sheet metal part without any used of die, and easy to adjust the part’s geometry by change toolpath. But the quality of forming parts is still in doubt. In some applications, such as mould cavity for rapid mould and the medical parts, in this case the inside surface roughness plays an importance role. In this paper, the SPIF process parameters that affected to the inner surface roughness were experimental studied. The investigated parameters are composing of tool feed rate, side overlap, depth step and tool radius. The 2k-p factorial experimental design was used to analyze the interaction between each parameter. The results showed that increasing feed rate and depth step decreased inner surface roughness. Reducing tool rotational speed and feed rate reduced inner surface roughness. So increasing depth step with decreasing side overlap reduced inner surface roughness. The large tool radius and lower side overlap improved inner surface roughness. The large tool radius and higher depth step improved inner surface roughness. And last, reducing tool rotational speed with larger tool radius, the inner surface roughness is decreased.

Abstract: This paper is focused on single point incremental forming (SPIF) of a tailored welded blanks (TWBs) that produced by laser welding process. The SPIF process is a new dieless forming technology, which is a fast and economic solution to prototyping a metal sheet product. In the past, the SPIF researches carried out with the homogeneous metal sheet blank, but now a day, the demand of TWBs is still increased especially for an automotive industry. The aim of this research is to study the formability on the weld line of laser welding TWBs (SUS 304 and St 37) by the SPIF process.

Abstract: Borophosphate glasses have been synthesized with a Bi₂O₃ concentration of 15.0 to 25.0 mol%, added 2.5 mol% for each concentration, by the normal melt quenching technique at 1200 °C. The physical and optical properties of bismuth borophosphate glass systems have been studied. The glasses are characterized for their physical and optical properties. The density and molar volume of these glasses were found in the range 3.4391 to 3.9338 g/cm³ and 52.2515 to 55.7557 cm³/mol, respectively. It was observed that the density and molar volume of these glasses was increased with increasing the concentration of Bi₂O₃. The absorption spectra of these glasses were recorded in the UV-Visible range. It has been found that, the absorption spectra were shifted to longer wavelength with higher Bi₂O₃ concentration. In addition, the oxygen packing density of glass samples have been also investigated.

Abstract: This work reports the influence of chemical composition and sintering schedule on the properties of sintered bodies of hydroxyapatite (HA) bioceramic. The method of preparing sintered bodies by solid state reaction and uniaxial pressing. The raw material used calcium carbonate (CaCO₃) and ammonium dihydrogen phosphate (NH₄H₂PO₄) powder as precursors. These powders were mixed at CaCO₃: NH₄H₂PO₄ mass ratio of 1:0.697, 1:0.692, 1:0.689, 1:0.685 and 1:0.68, respectively. The compositions in the temperatures range of 800-1300 °C for 3 hour. The sintered bodies were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR). Properties including phase, microstructures, porosity and bending strength of the samples. The results show that green bodies can be sintered at 1150 °C for 3 hours. This temperature found that crystals growth, highest of HA phase content in sintered bodies, good density and high efficiency strength properties.

Abstract: The single point incremental forming (SPIF) is a sheet metal forming process with high flexibility on manufacture of each individual workpiece. However, it usually requires more processing time than a conventional forming method and is important to process with appropriate parameters. This study is to investigate the influence of different temperatures on continuing secondary forming of Ti Gr2 sheet, employed the stress relieving and annealing temperature after primary forming. The deformed parts were examined on the following criteria; internal contact surface roughness, microhardness and sectional microstructure. Stress relieving and annealing temperatures of 580°C and 780°C were applied to the formed parts prior to their secondary forming. It is found that the surface roughness increased from Ra 2.104 μm and 2.498 μm to Ra 2.55 μm and 3.18 μm respectively after secondary forming. The formability of 25 mm radius test specimens remained at 12 mm depth with limited obvious change.

Abstract: In this work, TiO₂ thin films were prepared by a sol-gel spin coating method on glass slide, stainless steel 304 and silicon wafer substrates. The thin films were annealed at different temperatures at ambient atmosphere. The effect of substrates and annealing temperatures on microstructure, surface morphology and hydrophilicity of the films were characterized by Raman spectroscopy, atomic force microscopy and water contact angle measurement, respectively. The Raman spectra indicated that the annealed TiO₂ thin films (at 550 °C) coated on stainless steel and silicon wafer exhibited anatase structure. The contact angle of all samples decreased with increasing the UV-irradiation time and annealing temperature.

Abstract: The single point incremental forming (SPIF) is a manufacturing process which allows small batch and asymmetric shape fabrication. The research focuses on its applications by consider surface roughness and formability. The surface roughness of specimen was resulted by the influence obtained between tool and specimen, where the lubricant played a significant role during the forming process, as well as material elongation as a mechanical property governed the formability of metal sheet. Surface roughness tester, SEM, EDS and profilometer were used for the characterizations. The results showed that low roughness value (Ra) of SUS 304 and SUS 316L obtained by applying air blowing as a lubricant, while Ti Gr2 could obtain low roughness by using MoS₂. The behavior of wear was an adhesive wear which transfer to an abrasive wear. SUS 304 and SUS 316L sheet of test specimens achieved higher depth in forming by air lubricant and MoS₂, and Ti Gr2 sheet revealed a better formability with MoS₂. Furthermore, the highest depth was correlated with high roughness value for each material.

Abstract: Research has an objective to develop and fabricate thermoelectric generator module (TEGM) from the p-Ca₃Co₄O₉ and n-CaMnO₃ ceramic materials.The p-n materials were cut and polished to the dimension of 2 × 2 × 2 mm³ and 42 couples.The relationship between temperature difference and electrical voltage, electrical current, electrical power and conversion efficiency were measured. The electricity and efficiency of TEGM showed the maximum value of 5 V, 4.5 mA, 22.5 mW and 0.03 % at temperature difference of 100 K.