To evaluate the exploitation potential of wind energy in the coastal area of South Sulawesi, Indonesia, an investigation on the economic feasibility of this project was performed. A 300-watt horizontal wind turbine was used as an example installed turbine. The wind speed range of 4-7 m/s which was the wind speed data in the coastal area of South Sulawesi was computed. The main economic analysis method employed was Capital Budgeting Analysis (CBA) method. In this method, 4 (four) indicators were used to evaluate the feasibility of the project which are payback period (PBP), net present value (NPV), internal rate of return (IRR), and benefit-cost ratio (BCR). A visual basic computer program based on the CBA method was also developed to make the computation more convenient. From the study, it was found that the wind speed range of 4-6 m/s resulted in a non-feasibility project while the highest wind speed (7 m/s) was found to be quite strong to make the project feasible.

one way to reduce the scarcity of fuel oil is to make environmentally friendly alternative fuels such as biodiesel. The utilization of biodiesel can be a new energy source and also help reduce the excessive use of fuel, especially diesel and diesel oil in Indonesia. In Indonesia, the amount of palm oil will reach 49.7 tons by 2021, and this data is up 2.9% from the previous year. Palm fruit is processed into CPO. More palm oil processing will produce waste called POME (Palm Oil Mill Effluent). The diesel engine transesterification method is suitable for the manufacture of biodiesel. The amount of base on the catalyst's surface affects the catalyst's activity. So that the higher the base value on the catalyst, the higher the yield of biodiesel that will be produced. The biodiesel produced will be tested on a 4-stroke diesel engine with a B5 and B10 blending composition. The study's results showed that the density and viscosity values for B5 were 5.8 cSt and 810 Kg/m3 and for B10 were 6.3 cSt and 860 Kg/m3. As for engine performance, power, torque, and SFC for B5 fuel at 4000-watt load conditions and 1000 Rpm, engine speeds are 1.18 Kw, 11.28 Nm, and 256.8 gr/Kw. B10 at 4000-watt load condition and 1000 Rpm engine speed is 1.16 Kw, 11.12 Nm, and 269.2 gr/Kw.

The production of hydrocarbon fuels shows a downward trend which forces people to look for alternative renewable fuels such as biodiesel from vegetable oil. One solution that can be applied in the use of biodiesel mixed with castor oil. The purpose of this study was to determine the effect of using a mixture of castor oil on the performance of diesel engines. The method used in this experiment is testing it directly on a diesel engine. Experiments were carried out on machines with a load of up to 4000 watts by mixing pure diesel fuel with castor oil to produce biodiesel B10, B20, and B30 as fuel. The results showed that the use of castor oil biodiesel tends to be lower than diesel oil, the torque produced by B20 17,59 N.m is greater than diesel oil, and the thermal efficiency of B20 17,04 % and SFC B20 is 470,2 gr/kWh more economical than diesel oil. B20 provides better performance values foe diesel engines and this is the right solution to be an alternative fuel other than diesel oil.

Nowadays, steel ship construction in Indonesia is dominated by the hull block construction method. This method can reduce man-hours as the ship is manufactured by a division of the hull into several sections/blocks; here, it can be worked in parallel. Once work is finished on these blocks and then proceeding to the main hull for assembling, the lifting operation is performed on the blocks during this erecting process. Lifting of ship blocks must be planned safely to avoid damage. One of the items that must be considered is the position of the padeye. The placement or installation of the padeye in the block during the lifting operation plays a vital role in the deformation and working stress of the block structure. Consequences if this is not observed, which van cause misalignment in the welding join path on ship bloks due to excessive plastic deformation and stress. Therefore, this study aims to simulate the placement of a padeye that results in minimum deformation and structural stress. The method used in this research is the stiffness method applied in computer programs. In this studied, it had been recorded that the structure on the ship blok is deformed and stressed at each padeye position. Based on the simulation from 23 positions of the padeye, the optimal position of the pad eye is at position 10 in simulation 2 with deformation of x, y, and z coordinates which are 7 mm, 2 mm, and 7 mm, respectively. Generrally, In this case shown the deck girder and longitudinal beam structure is dominantly subjected to high deformation and stress in several position.   Keyword: Padeye,  Ship Block,  Lifting,  Deformation,  Stress.

No abstract