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Bamboo can be used as an alternative material because of inexpensive and good mechanical properties. The study aims to obtain the maximum tensile strength and compressive strength of laminated bamboo and Wood Class category according to BKI, using horizontal and brick blade arrangement. Tensile strength test was based on SNI 03-3399-1994 standard and compressive strength test was based on SNI 03 – 3958 – 1995 standard. It can be concluded that the tensile strength and compressive strength of petung bamboo lamination are better than Apus bamboo laminates with an average of 2412.72 kg / cm2 and 639.15 kg / cm2 respectively. As a result, laminated petung bamboo can be categorized in 2nd class of BKI Regulations.

Bamboo is a material that can grow quickly, cheap and widely available. Its material properties are lightweight but harder and stronger than wood or glass fibre composites. The purpose of this study was to determine the effect of the direction arrangement of petung bamboo blades on the interface of the laminated bamboo fibre matrix. The benefits of this research can contribute to knowledge and innovation to the development of science in the field of ship material technology in the world of education, especially in the shipping field. This research was conducted with a compressive test, tensile test, and shear test on the interface of petung bamboo laminate blade matrix with tangential or radial test direction (x, y, and z axis) using ASTM D143 standard. After testing, it can be concluded that the shear strength and compressive strength are better with perpendicular arrangement, while for tensile strength it is better paired with woven arrangement. The average results obtained for the tensile test was 41.29 kg / cm2 (4,049 MPa), the shear test was 39.98 kg / cm2 (3.92 MPa), and the compressive test was 311.24 kg / cm2 (30 For the average compressive strength of these results can be classified into Class III on BKI Wooden Ship For the best tensile test direction on the Y axis, the best shear test direction on the Z axis, and the best compressive test direction on the X axis. The greater the glue interface in each cm2, the greater the bond strength, because the level of homogeneity increases and the strength of petung bamboo is stronger than the PVAc glue used.

Not only the circle hollow pipe but also the rectangular hollow pipes are used on offshore structure. In this study, the bending moment was given at both end of pipe. The strength of buckling moment can be reduced by increasing the length. The rectangular pipe models are varying from a/b = 1, 2, 4; a/t = 10, 15, 20 and L/a = 10, 15, 20. On the rectangular pipe which is have larger rectangle area (a/b), have the larger deformation. Vice versa on the rectangular pipe which is have smaller rectangle area (a/b), as though on a/b = 2 and a/b = 4 which is have smaller deformation. The conclude that is the larger one of rectangle area then the oval deformation is large too. The buckling strength will increase with decreasing a/b and deformation at mid span will be increase. The buckling strength decrease with increasing of L/a and a/t. The strength of the buckling moment in the elastic state will decrease with increasing of a/t and a/b. For a/b = 1, the strength of buckling moment will tend to be equal at L/a = 10-20. Pipe with increasing of a/t, L/a and a/b will be elastic.

The objective of the present work was to investigate the mechanical properties of NiCr-Al coating deposited by plasma sputtering technique. NiCr was firstly deposited on a carbon steel surface using sputtering times of 60, 90, 120, 180 and 240 minutes, whereas Al was subsequently deposited using a time of 30 minutes for all specimens. The results showed that the structure of the surface observed by SEM indicates a good density. The structure formation of NiCr-Al was clarified by XRD. The hardness test of the product surface conducted by a Vickers indentation tester indicates that the average hardness of uncoated steel substrate was 172.512 HV. The hardness of NiCr surface was 191.256 HV. Further layer addition using Al on NiCr indicates that the hardness of NiCr-Al surface sputtered by NiCr for 60, 120, 180 and 240 minutes, followed by Al for 30 minutes, were 279.912, 253.056, 231.264 and 213.888 HV, respectively. The reduced hardness of NiCr-Al with the increased sputtering time was attributed to the higher diffusion of Al into NiCr.

Dissimilar welding of aluminum is an innovation used to increase the effectiveness and efficiency in making a product or component. It has been applied on the automotive industry, aerospace, and shipbuilding. Aluminum has low weldability in compared with steel material because of the oxide layer on the surface of aluminum. The welding problems of aluminum can be overcome by using a solid state welding such as friction stir welding (FSW). The objective of this study was to determine the strength of the welding joint and the microstructure of dissimilar welding joint with different series of aluminum. The tensile testing was performed with the weld directions of 0° and 45° to assess the formability, hardness testing, and microstructure of FSW. In this study, welding process was conducted to combine aluminum 1100 series (low strength aluminum) and aluminum 6061-T6 series (high strength aluminum) in the 2 mm thickness of aluminum sheet. The analysis was done by making comparison of the strength between dissimilar and similar aluminum series. The results showed that the dissimilar weld types, both in angle orientation of 0° and of 45° had fracture location on the HAZ area of 1100 aluminum series. The highest results of tensile strength were 78.07 MPa and 75.26 MPa for weld angle orientation of 0° and 45°, respectively. Weld angle orientation had significant effect to the strain where value of the welding direction of 0° was 10.99% and of 45° was 13.8%. Hardness test in the weld zone generated diverse values because the material stirring was not homogenous, whereas the similar welding was more stable in the welding area. Microstructure investigation on the dissimilar aluminum welding found a hook defects in the weld nugget. In the HAZ area, the grain size of 6061-T6 increased while of 1100 material decreased. It might be affected by the temperature and the aluminum characteristic. Meanwhile, in weld nugget, the grain size increased due to the stirring tool joint and heating during the welding process.

The objective of thiswork was to investigate the microstructure and adhesion of NiAl coating whichformed by self propagation high temperature synthesis (SHS) process. Ni/Almixture and an underlayer material which used Ni and Al were compacted to forma bilayer pellet and subsequently put on a steel substrate. The Ni/Al reactionwas ignited using induction heating in a combustion chamber of argon gas. Themorphology and microstructure of the products were observed using SEM and XRD.The results showed that further reactions between NiAl coating and underlayermaterials formed several intermetallic phases. The role of Al and Ni underlayeron the microstructure, porosity and the adhesion between coating and thesubstrate was observed.

The existence of fossil fuels is increasingly scarce nowadays. Therefore, finding alternative fuels to substitute petroleum fuels, especially gasoline that very huge used for a motor vehicle. One of the alternative fuels as a substitute for gasoline is bioethanol (BE). The aim of the research work was to analyze engine performance and exhaust emission level of vehicle using two different types of spark plug. Further investigation was addressed by varying additional bioethanol fuel made from raw material of cassava. The work was carried out experimentally both in the laboratory and engine test drive. The results show that by using platinum spark plug resulting better performance of engine. The additional bioethanol on fuel, the power, and torque generated from the engine increases with the increase of percent bioethanol in the fuel mixture. The fuel consumption is more efficient by using fuel of 30% BE, compared with engine operation using fuel of 100% pertalite. While the results of the exhaust emission on the vehicle show that by using fuel bioethanol, exhaust emissions decrease as the increase of bioethanol in fuel mixture than exhaust emissions generated when using fuel 100% pertalite. It was proved by statistical data analysis using a one-way ANOVA Varian (F test) for power, torque, and HC emission levels, found of F value less than F table. Therefore hypothesis null (Ho) was accepted. Further result in each variation of fuel there is no significant difference. However, for CO, found that counted F greater than F table, then Ho was rejected; therefore the result of each variation of fuel there is significantly different.

Hard chromium coatings has long been considered as the most used electrodeposited coating in several industrial applications such as in petrochemistry, oil and gas industries. When hard coatings used in fastener components, the sliding contact during fastening operation produces high tensile stresses on the surface which can generate microcracks. For component used in high oxidation and corrosion environment, deep cracks cannot be tolerated. In this work, a laminated structure of Cr-Cu coating was prepared using electroplating on carbon steel substrates. Two baths of chrome and copper electrolyte solutions were prepared to deposit Cr as the first layer and Cu as the second layer. The effect of current voltages on the thickness, hardness and specific wear rate of the Cu layer was investigated. The results show that an increase of the current voltages increased the thickness and hardness of the Cu layer, but reduced the specific wear rate. This study showed that the use of Cu can be a potential candidate as a laminated structure Cr-Cu for chromium plating.Hard chromium coatings has long been considered as the most used electrodeposited coating in several industrial applications such as in petrochemistry, oil and gas industries. When hard coatings used in fastener components, the sliding contact during fastening operation produces high tensile stresses on the surface which can generate microcracks. For component used in high oxidation and corrosion environment, deep cracks cannot be tolerated. In this work, a laminated structure of Cr-Cu coating was prepared using electroplating on carbon steel substrates. Two baths of chrome and copper electrolyte solutions were prepared to deposit Cr as the first layer and Cu as the second layer. The effect of current voltages on the thickness, hardness and specific wear rate of the Cu layer was investigated. The results show that an increase of the current voltages increased the thickness and hardness of the Cu layer, but reduced the specific wear rate. This study showed that the use of Cu can be a potential candidate as...

The objective on the research was to investigate the mechanical properties and microstructure of tailor welded blank (TWB) made from AA6061-T6 and AA1100 using friction stir welding (FSW) process. Due to the dissimilar mechanical properties of the two aluminium alloys, microhardness test was conducted to measure the hardness distribution across the weld nugget. The mixing of two distinct materials was influenced by tool rotation speed. Therefore, microstructure analysis was carried out to investigate the grain size and shape. The grain size of AA6061-T6 has increased in the heat affected zone (HAZ) while for AA1100 has decreased. In the weld nugget, it has found a hook defects in the dissimilar aluminium joining. By using monotonic tensile load, the different weld line direction was observed with the expansion in tool rotation. The joints failure were consistently on the area of AA1100 series. Furthermore, two specimens were investigated, one through the dissimilar aluminium and the other through similiar material. Inspection of the weld nugget hardness was shown that nonhomogen material intermixing during the stiring process as confirmed by microhardness measurement.