Key Engineering Materials Vol. 892

Abstract: The use of biodiesel fuel converted from vegetable-based oil are continuously increasing due sustainability and environment concerns. It is important to increase the portion of converted fuel from non-edible sources to reduce the use of food stock. In this study, the tribological properties of stainless-steel material was investigated when lubricated by two kinds of methyl esters converted from non-edible vegetable oils, i.e. Cerbera oil and Rubber seeds oil. The friction and wear were investigated by using a ball-on-disk tribometer at severe friction condition. The results show that the wear of material lubricated by both methyl esters was much smaller than that lubricated by petrol diesel fuel. At temperature of 27°C, the worn area on the ball specimens for the case of Cerbera and Rubber seeds methyl esters were 0.396 mm² and 0.391 mm² compared to 3.642 mm² for the case of petroleum diesel fuel. At 80°C, they were 0.410 mm² and 0.429 mm² compared to 4.152 mm² for the case of petroleum diesel fuel. This shows that both Cerbera and Rubber seeds methyl esters has a good tribological properties comparable to other methyl esters sources used for mineral diesel fuel substitute.

Abstract: In this study, iron removal was carried out by the adsorption process as a well-known method of removing heavy metal. Natural bentonite with magnetic properties in a monolithic form or Magnetite-Bentonite-based Monolith (MBM) adsorbent was used as an adsorbent to remove Iron (II) ion from the aqueous solution. The magnetic properties of adsorbents are obtained by adding magnetite (Fe₃O₄), which is synthesized by the coprecipitation process. The characterization of magnetic properties was performed using the Vibrating Sample Magnetometer (VSM). VSM results showed that the magnetic particles were ferromagnetic. Adsorption efficiency, isotherm model, and adsorption kinetics were investigated in a batch system with iron solution concentration varied from 2 to 10 mg/L and magnetite loading at 2% and 5% w/w. The highest removal efficiency obtained reached 89% with a 5% magnetite loading. The best fit to the data was obtained with the Langmuir isotherm (non-linear) with maximum monolayer adsorption capacity (Q_o) at 5% magnetic loading MBM adsorbent is 0.203 mg/g with Langmuir constants K_L and a_L are 2.055 L/g and 10.122 L/mg respectively. The pseudo-first-order (non-linear) kinetic model provides the best correlation of the experimental data with the rate of adsorption (k₁) with magnetite loading 2% and 5%, respectively are 0.024 min^-1 and 0.022 min^-1.

Abstract: The aim of the study to investigate the effect of welding current on the microstructure and mechanical properties of gas tungsten arc welding (GTAW) for dissimilar austenite Stainless steel (AISI 309 and 201). Three models of welding currents have been used and their effect on microstructure and mechanical properties investigated. The results reveal that increase of welding currents improved the ultimate tensile strength (UTS) however, the hardness of the weld zone and Heat Affected Zone (HAZ) are similar. On the other hand, the microstructure of base metal AISI 309 and 201of austenite, ferrite structure, and ẟ ferrite of AISI 309 stainless steel were observed.

Abstract: Corrosion is one of the main causes of early failure of infrastructure both for public housing facilities and public facilities in downtown Langsa. This corrosion is caused by air pollution generated from motor vehicle and household industry exhaust fumes and exhaust smoke from the nearest palm oil mill industry from the city of Langsa. Related to air pollution, its sustainability should be a concern regarding environmental impacts that occur, one of which is atmospheric corrosion. This study aims to analyze the impact of the effects of pollution on infrastructure corrosion on construction steel which is often used on infrastructure in the city of Langsa and the palm oil mill industry. There are five types of steel model infrastructure consisting of strips of plate steel, elbow steel, cylinder steel, plate steel, and low carbon steel market have become specimens. Calculation of corrosion rate using the method of mass loss by reference to ASTM standard G50, the location selected above buildings in downtown Langsa and palm oil mill industry. The results of the study for one year showed the level of corrosion rate that occurred in 5 types of steel construction is still relatively safe or its relative corrosion resistance can be classified in the outstanding category (<1 mil per year). The conclusion is that 5 types of construction steel that have been tested, are resistant to corrosion, and are suitable for use as the main construction material in Langsa City and the palm oil mill industrial environment.

Abstract: Silver nanoparticles (Ag⁰) have attracted the most attention due to their broad antimicrobial application and outstanding activity. The silver nanoparticles are usually in colloidal form, then immobilization the colloid onto solid support is still interesting to explore. In this work, a new method for silver colloidal nanoparticle immobilization on silica gel beads (SiG), which was then symbolized as Ag⁰-[chi-SiG] was conducted and characterized successfully. The finding proved that SiG must be coated with three chitosan film layers to give stable support for silver nanoparticles. This coating method caused the chitosan completely covered SiG, and the chitosan film provides coordination bonding for silver ions. The most appropriate solvent for silver ion impregnation on the surface of chi-SiG is methanol compared to other solvents. Tungsten lamp as the photo-irradiation, which is low cost and environmentally friendly has been proven effective for silver ion reduction, as shown by silver metal colloid UV-Vis surface plasmon resonance at 400-700 nm. Ag⁰-[chi-SiG] showed the antibacterial properties of inhibiting the growth Staphylococcus aureus and Escherichia coli; then it provides the potential application for antibacterial filter material. According to the weight comparison between antibacterial standard and Ag content, then Ag0-[chi-SiG] has two and five times higher of exhibiting zone for each bacteria.

Abstract: Original reactive powder concrete (RPC) consists of a large amount of cement, fine sand, crushed quartz, and silica fume, with a very dense matrix achieved by optimizing the granular packaging of the materials. This study, therefore, applied the modified Andreasen & Andersen particle-packing model using Aceh quartzite powder to design a densely compacted matrix and low cement content RPC mixtures. The research involved the preparation of two series of the mixture with different percentages of silica fume and Aceh quartzite powder and the 70.7 mm cube specimens were treated with combined steam curing and normal curing after which their compressive strength was tested at the age of 7 days and 28 days. The result showed the use of 61% local quartzite powder by weight of cement through an optimized mix design and cured treatment improves the RPC strength at any variation of silica fume.

Abstract: Due to repeated loads, the pavement structures will experience repeated stresses and strains resulting in permanent deformation even though the working loads are still smaller than the design load. The permanent deformation will lead to cracking and fatigue failure with the life of the pavement. This phenomenon can be reduced by increasing the stiffness, flexibility, durability, stability and water absorption of the pavement. Material modification including the utilization of waste tire rubber (WTR) and natural zeolite is one of the efforts to increase those parameters in semi flexible pavement (SFP). The aim of this study therefore, to assess the deformation and fatigue failure of SFP incorporating WTR and natural zeolite under cyclic loading. The WTR was used as an additive at the level of 3% of asphalt content while natural zeolite was used as cement replacement at the 0, 5, 15 and 25% replacement levels. Permanent deformation tests were conducted by applying wheel tracking loads with the pressure of 6.4 ± 0.15 kg/cm² on the surface of the specimens with 1260 cycles per hour while fatigue tests were conducted on the simple supported beams with the span length of 30 cm by applying forth point loading at the frequency of 10 Hz. The test results showed that the best performance in sustaining cyclic loading was achieved at the zeolite content of 5%.

Abstract: Plastic waste has been a major issue regarding waste in the world today. Plastic production in the world has reached 8300 million metric tons (Mt) from 1950 to 2015 and of about 6,300 Mt turned into waste. The development of industry and technology is often accompanied by the emergence of environmental impact issue. Encompassed plastic waste in nature causes problems, as it can drift from the land and fill the oceans around the world. Various plastic waste processing technologies have been introduced. Recycling plastic waste into goods, fuel oils and asphalt mixtures are things that have been done enormously. This research aims to make composite materials from used plastics, clay materials, and charcoal. A qualitative experimental method by heating the plastic waste below 270°C. Then, it is mixed with additional materials and casted the composite into a mold to form test specimens. Mechanical testing has been carried out to evaluate the composite. The results show that a composite material comprises plastic waste, clay and charcoal can provide maximum tensile strength of 14.59 N. The tested composite material is found to be 34.20% stronger than the material made of only plastic waste.

Abstract: This present study has been re-established to investigate failure mode and resistance characteristics of the PC/ABS blends and their ABS constituents under impact for a range of rubber contents. This present study has still been experimentally performed under an instrumented-drop weight impact test (DWIT) at a room temperature. It has been finally revealed that with a particular size of rubber particle, content of rubber significantly influenced impact failure modes and impact resistances of the PC/ABS blends and their ABS constituents as well. The test results showed that impact strength of the blends was improved about 23.22% and 155.33% due to increase in content of rubber up to 15 wt% and 20 wt%, respectively. There was also found that an increase in impact toughness of the blends for 57.48% and 239.23% was due to increase in content of rubber up to 15 wt% and 20 wt%, respectively. Whilst, impact strength of the ABS was improved about 392.98% and 190.12% due to increase in content of rubber up to 15 wt% and 20 wt%, respectively. An increase in impact toughness of the ABS for 308.20% and 172.56% was due to increase in content of rubber up to 15 wt% and 20 wt%, respectively.