Applied Mechanics and Materials Vol. 776

Abstract: Indonesia is one of countries with the potential for abundant natural resources, especially natural fibers. The potential of Indonesian natural fibers abundant is not fully put to good use to increase social welfare. One of the natural fibers that have the potential to be developed is the banana fiber. Banana fiber has potential in abundance and can be developed as a biocomposite material that is strong, inexpensive, environmentally friendly, and can be recycled. This study aims to produce a tensile strength of Banana Fiber Reinforced Epoxy Composite Materials (BFRECM). Testing of the tensile strength refers to the ASTM D 3039 / D3039M. Based on the research results, obtained the tensile strength of BFRECM (62.3 ± 0.67) MPa and modulus of elasticity (8.72 ± 1.12) GPa. Tensile strength obtained will be referred for further study of natural fiber composites.

Abstract: Recycled polypropylene (PP) and sisal fiber, which are available in abundant ammount, can be used for producing a composite, a new material that reduce production costs and environmental damage. The new materials will be used for manufacturing floor tiles that are environmentally friendly, light but still technically qualified, and are expected to replace the ceramic tiles that are relatively heavy. However, the drawbacks in the application, natural fiber is a combustible material and it absorbs water easily (hydrophilic). To overcome these obstacles then a study on fiber chemical treatment was conducted. The purpose of this study is to determine the effect of chemical treatments on sisal fibers for fire resistance capability, the moisture resistance and tensile properties of the composites. So these composite materials can replace ceramic tile that is used for houses, hotels, ships and so on. In this research, sisal fibers with length of 10 mm were treated by NaOH and followed by Vulcan AF21 (Vulcan) of 5%, 10% and 20% for 2-hours for fire resistance, and other treatment with Acrylic acid (AA) of 1%, 5% and 10% for 1 hour at 50°C for moisture resistance. Fiber material that has been chemically treated is mixed with recycled PP. Test specimens were made in hot pressed. Fire resistance testing was conducted based on ASTM D635 standards, water absorption testing (ASTM D570), and tensile testing. The result shows that the higher the percentage of Vulcan treatment on sisal fiber is of 5%, 10% and 20%, the linear burning rate, the percentage of weight loss and weight loss rate of sisal fiber polypropylene composites decreases which means the composite is more resistant to fire. In general, the increase percentage of Vulcan on treatment sisal fibers shows a decrease in tensile strength and modulus of elasticity but a slight increase tensile strain of composite. Fiber treated with acrylic acid (AA) experienced a reduction of water absorption compared to the untreated of fiber composites.

Abstract: Photocatalysis has been proven effective in controlling various environmental problems originated by pollutions both in liquid and gaseous phases. Titanium dioxide (TiO₂) is well known the most practical photocatalyst as it has high photocatalytic efficiency, low band gap energy, and no toxicity. Various chemical methods have been tried to produce TiO₂ photocatalyst powder with high activity. In this study, sol-gel method has been employed to produce nanosized TiO₂ photocatalyst particles and its physical properties and photocatalytic activity in phenol degradation test were compared with the commercial TiO₂ powder, Degussa P25. The synthesis process was carried out through hydrolysis of titanium tetraisopropoxide (TPT) and methanol where the molar ratio of water to TPT was monitored to control the hydrolysis rate. From X-Ray Diffraction (XRD) analysis, the sol-gel TiO₂ powder obtained was fully in anatase structure with high crystallinity. Scanning Electron Microscope (SEM) measurement showed that the powder was in nanoto sub-micron size, spherical in shape, and tightly agglomerated. Thermal analysis confirmed that sol-gel derived amorphous TiO₂ powder transformed to anatase phase after 400°C calcination. The test on photocatalytic performance conducted using aqueous solution of phenol as the representative of water pollutant examined in this study showed that the sol-gel TiO₂ powder is more efficient in degrading phenol compared to one of the most active photocatalysts commercially available, Degussa P25.

Abstract: For the past few decades, metallic materials that progressively degrade in physiological environment have been receiving attention with aim of finding appropriate biodegradable implant materials. This review focus mechanical and biocorrosion properties of Zn-based alloys that were recently investigated are summarized and discussed. In addition, the strategy for future fabrication to enhance the prospect of these alloys as metallic biodegradable materials is suggested.

Abstract: Hydroxyapatite powder has been synthesized from eggshell waste using a simple hydrothermal synthesis. The process involved drying and thermal decomposition of eggshell into calcium oxide followed by a hydrothermal reaction at a temperature of as low as 90°C with ammonium di-hydrogen phosphate and water. The produced hydroxyapatite powder is extraordinarily fine with nanosize primary particles. The yield of conversion is high, ca. 90%. Hydroxyapatite pure phase can be maintained until calcination of below 900°C, at which β-tricalcium phosphate phase started to appear to transform into biphasic calcium phosphate. Its high purity as proved by XRD shown that the product fulfills medical requirement. The present invention provides an environmentally beneficial and straightforward method of producing hydroxyapatite for bone implant materials using eggshell waste.

Abstract: This research purposed to know the performance of heat pipe using wick made from biomaterial. Biomaterial (Coral) is the porous media which has the relative homogenous and small porous structures. The homogenous structures and the small biomaterial have the better capillarity and could be used as wick to circulate condensate in heat pipe. The heat pipe made from copper pipe with 50 mm in length and the inside and outer diameter was 25 mm and 24 mm in each, with the wick as thick as 1 mm made from Tabulate. Heat sink was adhered to the condenser part of heat pipe as wide as 637.5 cm². The study was the observation of phenomena in porous media boiling between biomaterials with solid copper, in which the observations were made by using High Speed ​​Video Camera (HSVC). Tabulate biomaterial has the porous structure which quite homogeny and the best capillary energy. The biomaterial as wick heat pipe could keep the condition of heat pipe from easily reachs the transition condition.

Abstract: The main objective of this study is to determine the basic characteristics of fluidization using sewage sludge particle as non-visual phenomena which can then be modeled physically and numerically with the program of Computational Fluid Dynamic (CFD). CFD modeling using Eulerian model incorporating the kinetic theory for solid particles was applied to the gas-solid flow at various superficial velocities for different particle sizes. The transfer momentum was calculated using Syamlal-O'Brien drag function and Eulerian multiphase model was used for analysis. Two-Dimensional computational domains discretized using rectangular cells (Quad), made within the 20 iteration steps of 0,001s. The gas velocity is found to be the ​​the most important factors that influence the formation process of fluidization; by increasing the rate of fluidization the bed expanse occurs higher as well the time of onset fluidization is shorter. The phenomenon can be explained well by modeling and simulation.

Abstract: The solid waste produced from urban area is an urgent issue to be addressed. A fluidized bed (FB) gasification technology has been widely applied and proven effective to convert waste into clean energy and environmentally friendly. Co-gasification is a technique of mixing two or more fuels that aims to improve calorific value of the gas production. A FB gasifier reactor is designed using some previous experiments and available literature as well as from the internal experience of the research group. The gasification reactor pilot plant scale using data input of waste and biomass fuels has been fabricated with diameter of 0.7 m and a height of 1.5 m. The Tests have been performed showing that the FB gasifier is very feasible to be developed.

Abstract: Operation of the corresponding large machine is not allowed during the regular NDT period. Therefore, reducing the test period and extending the test frequency, i.e., lowering the machine stoppage time due to an inspection is a very important technique for efficient energy usage. For this reason, IT-based real-time non-destructive testing (IT-NDT) technology has been being developed. This presentation reports on a magnetic camera, which is one IT-NDT technology, including the up-to-date experiences.

Abstract: One of the most important criterion in the design of fixed offshore platform is to have strength from applied loads which is acting perpendicular to jacket leg section such as axial compression.The axial compressive load acts vertically downward to jacket legs and the deformation on the jacket legs in horizontal direction due to this load is called buckling. In the present study, buckling analysis on pechiko field of fixed offshore platform is performed using Finite Element Analysis (FEA). The fixed jacket platform namely tripod and tetrapod are taken as the object of the analysis. Only the axial compressive load is used in the analysis and the boundary conditions are assumed to be fixed both tripod and tetrapod at the bottom seabed. As a fundamental case, buckling analysis is carried out in plane-section (2D analysis), then the result obtained by FE analysis is compared with the analytical solution.It is found that the result obtained by FE analysis for the critical buckling load is in good agreement with the analytical solution, and the applicability of FE analysis is further used to investigate the deformation of 3D model.