Advanced Materials Research Vol. 789

Abstract: Microencapsulation is a new breakthrough in the field of nanotechnology that can be used for various applications, in particular for the application of controlled release material for functional textiles which were added by certain active substances and gave effects when used such as fragrance and anti mosquito textile. In this research, the synthesis of silica-lavender microencapsulation for anti-mosquito textile had been conducted successfully via sol-gel emulsion process. Sodium silicate solution which was emulsified into the lavender oil as an active ingredient acted as oil phase and ethanol solution acted as water phase. The addition of chitosan as surfactant and polymer for encapsulation with starch as soft template affected the rod-structure formation of nanorod. SEM result showed the morphology of silica-lavender. The rod has the average diameter size of 0.042-0.206 μm. The optimum result of rod-structure was obtained by adding 1% (v/v) of chitosan. FTIR analysis indicated the presence of absorbance peaks at wavenumber of 1411.89, 958.62, and 1078.2 cm^-1 respectively for C-H (alkanes), C-H (alkenes) and ester functional groups which indicated the lavender compound in silica-lavender. UV-Vis analysis showed the maximum absorbance at wavelength of lavender at 350 nm. The combination of morphology and chemical properties of silica-lavender modified by chitosan-starch made this material as a candidate material for application in functional textile.

Abstract: A sensitive layer is a main component in detecting an analyte target in a microcantilever-based biosensor. The sensitive layer coated on the microcantilever surface can induce a surface stress change as consequence of adsorbate-surface interaction. Therefore, a presence of stress is necessary to be investigated because it determines a deflection which influences the sensor sensitivity. In this work, we study a dependence of the film stress and microcantilever deflection on the gold or 3-Aminopropyltriethoxysilane (aminosilane) layers thickness in static mode operation. It is found that the optimum thickness of the sensitive layer for both aminosilane and gold can be obtained by analyzing the maximum film stress and the maximum microcantilever deflection. We also investigated the effect of Youngs moduli on the maximum stress and the maximum deflection. It is obtained that the Youngs moduli is a function that determines the peaks on the maximum stress and the maximum deflection. Our results indicate that the material properties and the thickness of sensitive layer should be considered to obtain a high sensitivity of microcantilever biosensor.

Abstract: NiTi alloy is one of important materials in orthodontics. Shape memory effect of this material ensures the possibility to deliver highly desireable light forces for thooth movement. Unfortunately, NiTi has problem in the high amount content of Ni that can cause allergy or even risk of poisioning in the human body due to Ni ion released. To overcome this problem, several methods of coatings were performed to prevent the releasing of Ni ion. They were Electropolishing Pretreatment combined with Photo Electrocatalytic Oxidation, TiN Pack Cementite, Advanced Oxidation Process and Biomimetic Hidroxyapatite. The objective of this research was to analyze the effect of various coatings to the biocompatibility of orthodontic wire. Biocompatibility of coated NiTi wire was investigated through MTT assay using BHK-21 fibroblast cell in order to analyze the toxicity of each coating method. In addition, the surface roughness was determined using Atomic Force Microscope (AFM). Furthermore, the attachment and spreading of fibroblast cell were observed by Scanning Electron Microscope (SEM). The result was revealed that biomimetic HA coating has the highest cell viability percentage due to its surface morphology.

Abstract: Bacterial cellulose-based carbon nanotube has been synthesized by catalytic graphitization method. Bacterial cellulose (BS) is a source of cellulose produced from fermentation of medium by Acetobacter xylinum. Since it contains unbranch polymer linked by β-1.4 glucopyronose with hydroxil groups, BS is able to use as precursor in synthesis of carbon nanotube. Due to catalytic graphitization, chitosan served as coupling agent and dispersant of catalyst and various concentration of catalyst FeCl3.6H2O also were used. Graphitization was conducted in furnace with inert nitrogen gas atmosphere at 800°C for 2 hours. SEM-EDS were used to evaluate the morphology and semi-quantitative analysis of sample. TEM was used to determine the microstructures and crystallographic. When the chitosan was added 0.5%, its served as coupling agent and dispersant of catalyst with BS. Chitosan improved physical properties, relieved its brittleness, and caused the optical properties of BS. Catalyst of FeCl3.6H2O was used to assist the formation and growth of carbon nanotube. The amount of carbon was not affected by time aging. 0.1 M FeCl3.6H2O was the optimum concentration to produce carbon nanotube with 81, 58% the mass of carbon, plane orientation (002) (100) and the diameter of carbon nanotube is 25 nm.

Abstract: Nanotechnology is one of the key technology had been developed since in all fields including textile industries for medical, hygienic, and technical textiles. Particle size with nanohad been indicated in particular for the application of controlled release material for functional textiles. TiO₂ nanopowder has remarkable photo-catalytic and semiconductor as material for various advanced technology fields of application such as UV Protection. In this research the synthesis of TiO₂ nanoparticle and characterization had been conducted successfully by sol-gel method. The starch was used as a template to get nanoparticles structure. TiO₂ sol with narrow particle size distribution using TiCl₄ as the starting material. The sol was prepared by a process where HCl was added to a gel of hydrated titanium oxide to dissolve it. The effect of preparation parameters were investigated, by deionized water : HCl 1 M was slowly added to TiCl₄ at 5 °C. In this study the production of anatase or rutile TiO₂ nanostructured powder by forced hydrolysis of aqueous Ti (IV) chloride solution and concentration from 0,3, 0,5 then 1 M. TiO₂ sphere were fabricated by a facile and low cost stable starch assisted by sol-gel method. Aqueous solution of starch was added and then heated in temperature 80°C and aqueous solution of ammonium hydroxide was added to adjust pH to 8. After aging period of time, the white precipitate was filtered and then calcined in temperature 500⁰ C. The as-obtained samples were characterize,kjnhjd by SEM (Scanning Electron Microscope), UV-vis diffuse reflectance spectroscopy, X-Ray Diffraction (XRD) and Brunauer Emmett Teller (BET) analysis. The particle size is less than 100 nm and if it uses template particle TiO₂ more uniform distribution and spherical shape with particle size 170 200 nm. Crystalinity particle is 4 19 nm and the phase structure of anatase and rutile. The energy band gap semiconductor TiO₂ synthesis is 3.1 to 3.7 eV. Surface area without template starch 40.655 m²/g, with total for volume 0.278 cm³/g and pore size of 27 nm, and used template starch surface area 35.488m²/g with total for volume 0.196 cm³/g and pore size of 22 nm. Based on this research, the best a crystal phase for UV protection application is rutile phase.

Abstract: The development of the airport always causes the noise impact to the surrounding environment.¹ Housing close to the airport will be annoyed by the aircraft noise, especially if the building is not added by absorber building materials. Housing lay out towards the runways as noise sources is also an aspect that should be considered. This research resulted building models equipped by simple material compositions that had capability in reducing the airport noise optimally. The decrease of the noise level found out from the research is caused by the value of Sound Transmission Loss (STL) of the building materials composition. The models of housing are laid out with a number of specific orientation angles towards the runway and resulted values of the highest noise level reduction.

Abstract: The use of synthetic and natural fibers in composite materials has been proven to increase strength and reduce required amounts of basic building materials. Previous research has determined that fibers have a high tensile strength and the potential to increase the cohesive and tensile strengths of asphalt mixtures. Additionally, previous research suggests that skid resistance is influenced by changes in the asphalt penetration grade. Short decorticated and pulp coconut fibers were used as additives in this study. Short coconut fibers measuring 0.5-1.25 cm were mixed with pen 60/70 asphalt to yield fiber contents of 0%, 0.75% and 1.5%. The fibrous asphalt was mixed with asphalt-concrete-wearing-course-grade aggregate. The asphalt concrete mixture was molded and compacted with a wheel tracking compactor using an 8.16-ton standard vehicle axle load. Specimens were subsequently tested with a British pendulum tester at temperatures of 26 oC, 30 °C, 35 °C, 40 °C, 45 °C, and 50 °C. Skid resistance decreased with an increase in pavement surface temperature. The inclusion of 0.75% coconut fiber in the asphalt mixture improved skid resistance but did not improve resistance to increased road surface temperatures.

Abstract: In ceramic tiles industry, the process of ceramics classification plays an important part. At present, the process of classification is carried out manually by using the human eyes observation. However, the capability of the human eyes is very limited. This condition leads to the low accuracy of the ceramic tile selection. This paper proposes a mechanism which could classify the ceramic tiles automatically using local texture feature. The result of our experiment shows a recognition rate of 76%, which means that this method can be used to classify the ceramic tiles.

Abstract: In this investigation, mullite ceramics were produced by mixing Al₂O₃ and amorphous silica xerogel (SX) extracted from sago waste ash. The composition was prepared by adding an amount from 0 to 80 mol% of Al₂O₃ into SX. The samples were dry pressed and sintered in the temperature range between 900°C and 1200°C. Their properties have been characterized on the basis of the experimental data obtained using thermal analysis (DSC/TGA, X-ray diffraction and scanning electron microscopy (SEM). The results show that two major differences become obvious when comparing the samples loaded by the smaller and larger amount of Al₂O₃. First, cristobalite formation is retarded in the sample loaded by the larger amount of Al₂O₃. Second, at 1200°C, the observed volume fraction of mullite is higher in the sample loaded by the larger amount of Al₂O₃. The DSC analysis indicates that the mullite crystallization takes place at 1200°C for 60 mol% Al₂O₃ loaded SX sample as confirmed by the XRD pattern. It was found that there was not a complete reaction of mulitization for sample sintered up to 1200°C.

Abstract: The acoustical properties of polyester/ramie fibre composite materials that was applied as a sound absorbing material is discussed in this paper. The aim was to determine the correlation between Normal Incidence Sound Absorption Coefficient (NAC) and Random Incidence Sound Absorption Coefficient (RAC) of the fibre composites. The acoustic measurement with Impedance Tube Kit followed the ASTM 1986 E – 1050 – 98 standard. The portion of the ramie fibre was modified with fibre length varied from 0.25 cm, 1 cm to 1.5 cm but at a constant fibre diameter. A constant volume fraction of fibre 20 % was used.The Beevers method was applied to characterize the fibre’s diameter. Results indicated that the sound absorption performance of the composite fibre can reach as high as 99% at frequency of 1225 Hz at aspect ratio of 42. A correlation between NAC and RAC was presented based on a quantitative result.