No abstract

At the coastal areas of South Sulawesi, Indonesia, there are many of villagers work as fisherman, shrimps and fish farmers. Most of them use aerator paddle wheel that are operated by high wattage motors that are ranged from 750 Watt to 1000 Watt. Some others use gasoline engine for one aerator every day. Consequently, the use of high wattage motors will cost the farmers and the use of gasoline will contribute to the air pollution. Therefore, it is necessarily important to invent a renewable base energy source for aerator which in turn economically effective that in the same time could apply the energy diversification. Fortunately, solar and wind potency are quite promising in the area. In this paper, an investigation, examination and application of hybrid solar-wind turbine generator are conducted and applied to aerator paddle wheel for shrimp’s pond. The required energy is 420 Wh/day. The measured average wind speed at Pancana Village is ranged from 3.25 m/s to 5.28 m/s. The averaged solar radiation potency in the village is 975 W/m2. The hybrid system is a combination of two 150 Wp solar panels and 500 W wind turbine. The experimental result show that the solar panels could generate energy by about 370.54 Wh in average, while wind energy could generate 165.60 Wh energy every day. Therefore, it can be concluded that the required energy of the aerator at average paddle wheel of 80 rpm can be fulfilled although solar energy is dominant as energy supplier.

Medical waste has become a major problem today in Indonesia because of the COVID-19 pandemic which has resulted in many hospitals being full of patients, resulting in an increase in medical waste. Handling of waste that is carried out is still not appropriate so that waste accumulates in garbage collection sites and in final disposal sites. As a result, the waste becomes a means of germs, bacteria, and animals that can spread disease to the surrounding environment. One way that is often used is to burn waste to reduce its volume. The incinerator is a modern means of burning waste by using a combustion system up to a temperature of 1000°C and can reduce the volume of waste by up to 90%. The research method used in making the design of the incinerator is starting from the design of the combustion chamber, the manufacturing and assembly stages, until testing is carried out on the tool. The test results from the incinerator can accommodate as much as 5kg to 10kg of waste with a combustion chamber volume of 0.165 m3. The highest temperature of the incinerator is at minute 15 with a temperature reaching 270.6°C, while the lowest temperature is at minute 150 with a temperature of 42.5°C.

The purpose of this study was to determine the effect of heating on the welding process of SMAW (Shielded Metal Arc Welding) in terms of hardness and microstructure of welded metal. Much welding has been done by preheating but below the temperature used below the initial martensitic temperature which reaches 452° C, this data is sourced from research by S. Zheng et.al and Y. Huang et.al. For this reason, an experiment was carried out with heat temperatures above a martensitic temperature of 500° C. The results show that in the Weld Metal area the pearlite structure appears larger, the effect of current strength on HAZ width is directly proportional, the greater the current strength, the wider HAZ, and hardness are affected by the rough grains of martensite.

Abstrak- Kondisi geografis Indonesia yang terdiri dari ribuan pulau menyebabkan masih banyaknya daerah terpencil yang belum terjangkau listrik PLN. Masih banyak daerah-daerah terpencil yang belum terjangkau oleh jaringan listrik.Salah satu pulau yang memanfaatkan potensi energi surya adalah Pulau Kodingareng yang memiliki PLTS dengan kapasitas 400 kW, namun sekarang ini PLTS tersebut mengalami kerusakan pada komponen baterai dan inverter. Sehingga studi ini akan menganalisis kelayakan rekondisi PLTS Kodingareng dengan menggunakan dua skema, Rekondisi skema 1 mengganti komponen yang mengalami kerusakan sesuai dengan spesifikasi yang ada pada saat ini. Sedangkan Rekondisi skema 2 mengganti komponen yang mengalami kerusakan berdasarkan perhitungan ulang dari kebutuhan pembangkit yang tersedia.Berdasarkan dari hasil perhitungan yang menggunakan metode Net Present Value (NPV) dan metode Internal Rate of Return (IRR). Kita dapat menyimpulkan dari hasil analisis Rekondisi skema 1 diperoleh hasil yang tidak layak pada kedua metode  dengan nilai dari NPV yaitu Rp. -9,781,952,693,- dan nilai IRR yaitu -52,48%. Sedangkan pada analisis Rekondisi skema 2 diperoleh hasil layak pada kedua metode yang digunakan, dengan nilai dari NPV yaitu Rp. 1,112.194.399 ,-dan nilai IRR yaitu 24,24%.