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All Journal Sprocket : Journal of Mechanical Engineering Jurnal Visi Eksakta
Siagian, Lestina
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KAJIAN TERHADAP KARAKTERISTIK PERPINDAHAN PANAS PADA LOOP THERMOSYPHON SEBAGAI ALAT RECOVERY PANAS TEMPERATUR RENDAH Siagian, Parulian; Siahaan, Saloom Hilton; Siagian, Lestina
Jurnal Visi Eksakta Vol. 1 No. 1 (2020): Jurnal Visi Eksakta : Edisi Juli
Publisher : LPPM Universitas HKBP Nommensen

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1248.682 KB) | DOI: 10.51622/eksakta.v1i1.48

Abstract

The purpose of this study was to examine the effectiveness of the Loop Thermosyphon Heat Exchanger (LTHE) fluidized R134a refrigerant at variations in working fluid pressure of 0.8MPa and 1.2MPa. Thermosyphon is made of three parts, namely, evaporator, condenser and adiabatic part. Evaporators are made of 3/4 inch diameter copper pipe with a length of 3.5 cm. The condenser is made of 3/4 inch diameter copper pipe with a length of 15 cm. The adiabatic part of the steam line is made of copper pipes with a diameter of 3/4 inches and a length of 25 cm and a liquid line with a diameter of 3/8 inches with a length of 27 cm. Things that were investigated included the effect of air flow velocity (heated fluid) of 0.8 m/s, 1m/s, and 1.2m/s on the effectiveness of LTHE and the effect of an increase in evaporator temperature by 400C, 500C, and 600C on the effectiveness of LTHE. The study was conducted experimentally where the LTHE evaporator was heated with a heater. The results of this study show that the effectiveness of LTHE heat transfer work pressure of 1.2 MPa pressure is about 30-68% and higher than the effectiveness of LTHE heat transfer work pressure of 0.8 MPa pressure about 22-35%. Effectiveness decreases with increasing airflow velocity. The LTHE thermal resistance of 0.8 MPa pressure is around 0.3-0.450C/ W and is greater than the LTHE thermal resistance of 1.2 MPa pressure around 0.08-0.40C /W.
Pengaruh Bahan Bakar Biodiesel dari Dimetil Ester Terhadap Kinerja Mesin Diesel Empat Langkah Sitorus, Tulus Burhanuddin; Zebua, Yosua F.S.R; Sinaturi, Daniel F.B; Siagian, Jonathan A.R; -, Suprihatin; Siagian, Lestina
SPROCKET JOURNAL OF MECHANICAL ENGINEERING Vol 3 No 2 (2022): Edisi Februari 2022
Publisher : Program Studi Teknik Mesin, Universitas HKBP Nommensen, Medan

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (823.123 KB) | DOI: 10.36655/sprocket.v3i2.649

Abstract

This study aims to determine the effect of biodiesel fuel from dimethyl ester on four-stroke stationary diesel engines' performance and exhaust emissions. Tests were carried out using B10 and B30 fuels with engine speed variations and load variations without modifying the engine. The results showed that the torque, power, and thermal efficiency tended to decrease when using B10 and B30. In addition, the specific fuel consumption has increased when the engine uses B10 and B30. But exhaust emissions of CO and unburned hydrocarbon (UHC) decreased NOx and increased CO2 when the engine uses B10 and B30. This research also obtains the correlations and regression equations involving engine performance parameters.
Analisa Kebutuhan Energi Termal Pada Kotak Pengering Biji Kopi Arabica yang di Isolasi dengan Aluminium Foil Siagian, Parulian; Napitupulu, Richard A. M.; Tampubolon, Miduk; Siagian, Lestina
SPROCKET JOURNAL OF MECHANICAL ENGINEERING Vol 4 No 2 (2023): Edisi Februari 2023
Publisher : Program Studi Teknik Mesin, Universitas HKBP Nommensen, Medan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36655/sprocket.v4i2.946

Abstract

The experiment test was carried out to obtain the composition of the caloric quality needed to determine the water content and the mass amount of coffee beans when they were dried by utilizing the sun's heat. Heat transfer processes by convection, conduction and radiation play an important role in the drying process with heat quality. Ambient temperature data of 350C with a constant fan rotation speed of 1.0m/s. The duration of the test is 5 days where the initial sample weight is 5000gr with the final result being a water content of 12-15%, with a duration of testing per day for 10 hours starting at 08.00-18.00Wib. The final drying weight of coffee beans for 5 days is: 2500.21gr with an initial weight of 5000kg. The temperature difference around the box is 31,110C. heat weight to evaporate water content Qh= 65.6058.kJ. and the heat required in heating the Coffee beans is 72,839 kJ. The ability to dry 5000gr of coffee beans requires total heat: 138.43kJ with a drying box volume of 8.88m3.
Analisa Pengaruh Pendingin Terhadap Struktur Mikro Dan Sifat Mekanik Pada Baja ST 60 Siagian, Parulian; Nababan, Wilson Sabastian; Manurung, Charles S.P; Lumbangaol, Partahi; Siagian, Lestina; Manurung, Wany Chytra
SPROCKET JOURNAL OF MECHANICAL ENGINEERING Vol 5 No 2 (2024): Edisi Februari 2024
Publisher : Program Studi Teknik Mesin, Universitas HKBP Nommensen, Medan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36655/sprocket.v5i2.1406

Abstract

The field of industry that produces human needs is growing rapidly. Encouraging increased productivity with iron metal-based machine components. Using quality materials, and certified. This research uses ST 60 steel with a carbon content of 0.48%.. The research process that will be carried out is Heat treatment is needed to minimize failure, change the structure, and form the desired properties, the rapid cooling process to produce a comparison of hardness in material variations, hardness testing to determine the hardness of a material, and observation of microstructure to observe the type of microstructure formed after heat treatment and without heat treatment. After testing, the heat treatment process greatly affects changes in the mechanical properties of the material, as evidenced by the increase in hardness values which initially before the heat treatment process amounted to 194.6 Kgrf / to 255.53 Kgrf / with SAE 40 lubricant cooling media, 220.43 Kgrf / with 50% lubricant cooling media with 50% water mixture, and 300, 7 Kgrf/ with long life coolant media and it is proven that in each material given heat treatment the hardness value has increased as well, before heat treatment the hardness value in ST 60 steel is only 194.6 Kgrf/, experiencing an increase in mechanical properties, namely work with SAE 40 lubricant cooling media with a value of 255.53 Kgrf/, 50% lubricant cooling media with 50% water mixture worth 220.43 Kgrf/ and long life coolant of 300.7 Kgrf/.
Co-Authors Lumbangaol, Partahi Manurung, Charles S.P Manurung, Wany Chytra Nababan, Wilson Sabastian Richard A M Napitupulu Siagian, Jonathan A.R Siagian, Parulian Siahaan, Saloom Hilton Sinaturi, Daniel F.B Suprihatin - Tampubolon, Miduk Tulus Burhanuddin Sitorus Zebua, Yosua F.S.R