No abstract

Based on its characteristics, biodiesel has a higher density, viscosity, and acidity level than diesel fuel, so it has a disadvantages in terms of lubricants especially in the long run. The impact, it can decrease the kinematic viscosity of the lubricant, a decrease in the total base number, and the impact by decreased of the engine performance. This research aims to determine the characteristics of lubricants from the use of biodiesel (B20 and B100) related to the kinematic viscosity of lubricants and Total Base Number (TBN). The testing method were used ASTM D2896-15 and ASTM D445-06 standard. The study used two units Kubota RD 65 DI-NB diesel engines with a cylinder volume of 376 cc. The rotary speed of the machine was keep constant at 2200 rpm and were operated for 300 hours non-stop. Moreover, the sampled was carried out every multiple of 100 hours. Based on the research results, the quality of lubricants with B100 fuel is no better than lubricants with B20 fuel. B100-fueled lubricants have kinematic viscosity values at temperatures of 40 °C and 100 °C and has lower TBN values than B20-fueled lubricants.

Penggunaan bahan bakar alternatif selalu berkaitan dengan dua masalah global, yaitu meningkatnya penggunaan minyak mentah dan cadangan minyak yang semakin menurun. Disamping itu, sumber energi alternatif menjadi topik yang menarik untuk terus dikaji. Indonesia adalah salah satu negara penghasil minyak kelapa sawit terbesar di dunia dengan nilai produksi mencapai 51,8 juta ton pada tahun 2019. Salah satu sumber energi alternatif yang dapat diolah dari minyak sawit adalah biodiesel. Biodiesel dapat digunakan secara langsung sebagai bahan bakar untuk mesin diesel. Tetapi biodiesel memiliki karakteristik yang berbeda dengan solar sehingga akan mempengaruhi unjuk kerja dan hal lainnya pada mesin. Oleh karena itu, penelitian ini akan menentukan pengaruh penggunaan biodiesel terhadap unjuk kerja mesin yang mencakup daya mesin, torsi, konsumsi bahan bakar spesifik (SFC), dan efisiensi termal. Bahan bakar yang digunakan adalah B100 (100% biodiesel minyak sawit) dan bahan bakar B20 (20% biodiesel minyak sawit + 80% solar) sebagai pembandingnya. Pengujian dilakukan selama 300 jam operasi, dengan beban konstan berupa lampu halogen sebesar 4 kW. Menurut hasil penelitian, mesin berbahan bakar B100 menghasilkan daya, torsi, dan efisiensi termal yang lebih rendah masing-masing sebesar 2,17%; 0,76%; dan 1,25% serta menghasilkan SFC yang lebih tinggi sebesar 14,61% bila dibandingkan dengan mesin berbahan bakar B20. Hal tersebut dikarenakan karakteristik bahan bakar B100 yang memiliki nilai kalor lebih rendah dan viskositas serta densitas lebih tinggi dibandingkan bahan bakar B20.

Scale is forming and controlling in industrial applications causes the clogs or decreasing in volume flows in the pipes, so increasing maintenance cost can occur as a consequence. Struvite discovered as Magnesium Ammonium Phosphate Hexahydrate (MgNH4PO4.6H2O) and referred as a scale due to the heating process of fluid through pipes. The aim of this research was investigated the temperature effect on process of scales forming and controlling. The process was used a vertical bulkhead reactor. The process starts from mixing the equimolar solutions of MgCl2, NH4OH, H3PO4 with 1: 1: 1 of ratio concentration. Then, crystallization process was carried out with the condition at the variation of temperature (20-40°C), variation of pH value (pH 8-10) and variation of air inlet rate (0.25; 0.50; 0.75; 1.0; 1.25 L/min) while the feed rate was 25 ml/min. The process continues until the condition becomes steady state. The scale controlling process was determined by the presence of struvite deposits. The deposits were analyzed by using the XRF method to determine composition content. The optimal conditions were obtained at a temperature of 30°C, pH 9, and air rate of 1.25L/min.

Currently, the need for clean water which is a vital source for people's lives has not been fully met for all Indonesians, including the mountain farming community, Jajar Village, Gandusari District, Trenggalek Regency. So far, the mountain farming community members of Jajar Village have used mountain water for household needs where cloudy and unstable water conditions are a problem that must be faced. If this problem continues, it will lead to serious health problems and social conflicts in the community. Therefore, through community service activities, we made a practical clean water treatment tool, with easily obtained materials, that can be implemented in hilly areas such as in Jajar Village, Gandusari District, Trenggalek Regency. The filtration system used is an upflow and downflow system where the water undergoes a filtration process twice in the material that has been selected and arranged in a systematic way. The materials used are available and easy to obtain in Jajar Village, so that people can discover easily about the benefits of these materials. After making a water filtration system with the community, then physical testing is conducted on the quality of the water produced. From the test results of the effectiveness of the implementation of clean water treatment technology applied to mountain farmers in Jajar Village, it shows that in general the filtered water has met the physical requirements for the level of turbidity, taste, and smell, as well as the quantity and continuity of water are always available when needed.