Key Engineering Materials Vols. 675-676

Abstract: This research work aims at characterize and analysis the physical and chemical properties of chitosan which derived from the Anadara granosa Shell. The physical and chemical properties have been also discussed in detail with X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR) Spectroscopy and Energy Dispersive X-Ray Fluorescence (EDXRF). The result showed that the XRD pattern indicated the Anadara granosa shell have crystalline structure of CaCO₃ in Aragonite phase, while chitosan powder which extract from Anadara granosa shell has amorphous-crystalline structure. Another that, FTIR results confirmed the deeply formation of intermolecular bonding between the functional groups of the sample which the spectrum of FTIR indicate that the characteristic feature of Aragonite phase with the band of FTIR at ~1083 while the band at ~1653 were agree with chitosan polysaccharide. In addition, the EDXRF result were indicated that the concentrations of organic compounds in chitosan which extract from Anadara granosa shell have concentration is 33.581Wt% while the Anadara granosa shell have 0.033 Wt%. For Calcium (Ca) element the chitosan powder have concentration is 66.157 Wt% while the Anadara granosa shell have 99.850 Wt%.

Abstract: In present work, tin-pigmented alumina (Sn-Al₂O₃) solar absorber on the aluminium substrate was successfully prepared by anodic anodization and further characterized by different methods. The phase, morphology, reflectance (R) and thermal conductivity of the Sn-Al₂O₃ solar absorber were measured by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) equipped with energy dispersive X-ray (EDX) analyzer, and Ultraviolet-visible-near infrared spectrophotometer in the wavelength of 300-2500 nm. The solar absorptance (α) was calculated based on the relationship of the spectral reflectance, R(λ), and the solar spectral irradiance of AM 1.5, I_s(λ), in the wavelength interval of 300-2500 nm. As the results, the surface color of the Sn-Al₂O₃ film was dark-black color. The XRD pattern of Sn-Al₂O₃ films was indexed as aluminium and tin phases. The chemical composition of the Sn-Al₂O₃ films composed of tin (Sn), aluminum (Al) and oxygen (O) elements. The average thickness of the produced films was 18.9 μm. It was found that Sn-Al₂O₃ films showed the low R (0.09) and high α (0.93) values for the whole wavelength 300-2500 nm, corresponding to theoretical properties of the solar absorber. Therefore, it can be concluded that the Sn-Al₂O₃ film on aluminium substrate can be applied to be the solar absorber in solar collector due to high α, which is similar to the commercial solar absorbers.

Abstract: In tussue engineering, hydrogel-based scaffold is one of the most common method for bone tissue engineering. Gelatin is a common material for scaffold, whereas hydroxyapatite (HA) has a similar composition and structure to natural bone mineral. HA can also increase cell adhesion ability of the scaffold. This research focuses on the fabrication of hydrogel scaffolds using gelatin composite with nanocrystalline hydroxyapatite (nHA). Then the mechanical and physical caharacteristics of the scaffold is investigetad. Low contents nHA is introduced into gelatin in order to modulate mesenchymal stem cell (MSC) behavior. There are three types of scaffolds which contain various HA content. The gelatin is crosslinked with glutaraldehyde before freeze-drying. The Young’s modulus of the surface is investigated using Atomic force microscopy (AFM). The pore size is investigated using scanning electron microscope (SEM). Human MSCs are culture on the scaffold for 3 weeks. The result shows the sucesse in cell cultivation. However, the human MSCs cultured on the fabricated hydrogels do not show any lineage-specific differentiation.

Abstract: In this research, a Ni-Al solar absorber was successfully prepared by the flame spray technique with Ni-5 wt.%Al particles as a starting material. The Ni-5 wt.%Al particles were melted and sprayed onto the outer surface of a stainless steel 316L tube in order to form a Ni-Al composite coating. The phase, morphology and reflectance (R) spectrum of the Ni-Al solar absorber were characterized by X-ray Diffraction (XRD), a Scanning electron microscope (SEM) equipped with an energy dispersive X-ray (EDX) analyzer and an Ultraviolet-visible-near infrared spectrophotometer at the wavelength 300-2500 nm. The results revealed that the surface of the Ni-Al solar absorber was rough, and its cross section was overlapped layer by layer. The Ni-Al solar absorber was composed of Nickel (Ni) and aluminum (Al) phases. NiO and Al₂O₃ phases were also found on the surface. The chemical composition of the Ni-Al solar absorber was Ni (72.94 wt.%), Al (11.76 wt.%) and O (15.29 wt.%). The solar absorptance (α) of this solar absorber was 0.77. This demonstrates that a Ni-Al composite coating can be applied as a solar absorber material for solar collector at high operating temperatures.

Abstract: The aim of this study is preliminary survey the natural material and investigates physicochemical properties of cellulose and chicken eggshell. The chickeneggshell as natural material which used as film filler in the cellulose/CaCO₃ biocomposite. The potential and the possibilities of chicken eggshell to use as filler were studied with three conventional analysis techniques, X-ray Diffraction (XRD), Energy Dispersive X-ray Fluorescence (EDXRF) and Fourier transform infrared (FT-IR) spectroscopy. It was found that the structural of chicken eggshell have calcites phase and the structural of cellulose have amorphous crystalline phase while the chemical composition of both material were investigated by EDXRF which show the organic compound as major element in cellulose but in chicken eggshell the major element is organic compound and calcium (Ca) element. The deeply investigate molecular composition by FT-IR which show the characteristic feature have been studied.

Abstract: Cobalt-doped ZnO powders with various dopant concentrations were synthesized using a simple-solid method. ZnO and Co₃O₄ powders were employed as the precursors. The powders were annealed at 500 - 900 °C in air. The crystal structural and magnetic properties were studied by means of XRD and VSM, respectively. The XRD patterns show the hexagonal wurtzite structure of the powders. The magnetic measurements by H-M loops reveal the combination of paramagnetism and ferromagnetism as well as the influence of Co dopant to magnetic properties of Zn_1-xCo_xO.

Abstract: Waste recycling was interested to both industrial and academic sectors. This study focuses on the use of sludge cake from wastewater treatment plant of a cosmetic industry as Magnesium oxide source. Cordierite obtains good chemical corrosion resistance, fine mechanical properties, good thermal conductivity, and most of all low coefficient of thermal expansion (COE) which is needed for ceramics industry. Magnesium is one of the main materials in cordierite, can be attained from different sources. In this research, Sludge cake from cosmetic industry was used as Magnesium sources for cordierite synthesis. The raw materials were ground, pressed, and sintered between 1200°C to 1325°C for 1 hour. The samples were investigated by X-ray diffraction technique and tested for thermal shock resistance, firing shrinkage, and water absorption. The XRD patterns showed that the increasing intensity of cordierite phase, the higher firing temperature presented the greater of cordierite phases. The findings were confirmed by the peaks of cordierite at 2q of 10.41° of samples when fired at 1325°C. It can be concluded that cordierite could be synthesized by using raw material from waste with other commercial raw material in different temperatures. Results showed that the sludge cake from wastewater treatment plant of Cosmetic Industry in Thailand is a promising as raw material and beneficial to Thai ceramics industry in terms of cost saving, competitiveness and environmental.

Abstract: An instrument based on electromagnetic induction method for detecting magnetic material in soil subsurface has been developed. The instrument consists of a signal generator, an amplifier, a transmitter, receivers, detectors and a display. A coil is used as transmitter. As receiver and also detector is used a three dimensional self-developed fluxgate sensor. The fluxgate sensor consists of two pick-up coils, four excitation coils, and a ferromagnetic core. The output voltage of the sensor is processed using an analog signal processing circuit. The sensor’s capability in detecting magnetic material in the soil subsurface was observed by placing a sample of magnetic material in the subsurface, and then detected using fluxgate sensor in the direction of the x, y and z (3D). We found that the developed instrument is capable to detect two different objects that is separated at minimum distance around 10 cm with the maximum shallow depth of the target material is 10 cm.

Abstract: Composites between mullite and modified BT were prepared by a conventional technique. The samples were calcined at 1300 °C for 2 h. The composites were sintered at 1250 °C for 2 h. The dielectric and mechanical properties the samples were investigated. The mechanical properties were found to improve after sintering at a suitable temperature. Addition of the BT produced an improvement in dielectric constant due to the BT has high piezoelectric properties. A higher dielectric constant for a sample contained higher amount of the BT was related with a higher polarization in the samples.

Abstract: The pad dyeing offers the most economical and convenient method of dyeing cotton fabric. The energy and water consumptions are at the lowest, thus rendering it more eco friendly. The dyeing of cotton fabric was carried out with dye extraction from the uncaria gambir by using two padding techniques, namely the pad-batch and pad-cure techniques under different conditions. The effect of dyeing method and mordant on color strength and colorimetric parameters (L*, a*, b*, and ΔE) were evaluated. The color fastness to wash, light and perspiration after dyeing the cotton fabric treated with the mordant was determined according to AATCC test method. The study showed that the color strength (K/S) of the dyed cotton fabric using pad-cure method higher than those dyed cotton fabric using pad-batch method. Meta-mordanting showed increase dye uptake and color fastness of cotton fabrics.