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Journal : G-Tech : Jurnal Teknologi Terapan

Analisis Pengaruh Arus Listrik dan Elektroda Terhadap Kekuatan dan Kekerasan pada Proses Pengelasan SMAW Baja Karbon Rendah Enos Tambing; Thomas Pagasis; Obet Takke Ranteallo; David Mangallo; Samuel Parlidungan Siregar; Agustinus Agustinus
G-Tech: Jurnal Teknologi Terapan Vol 8 No 2 (2024): G-Tech, Vol. 8 No. 2 April 2024
Publisher : Universitas Islam Raden Rahmat, Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33379/gtech.v8i2.4070

Abstract

Pengelasan SMAW, merupakan metode umum dalam pengelasan busur listrik, menjadi fokus penelitian menggunakan pelat baja karbon rendah dengan variasi diameter elektroda. Tujuan utamanya adalah mengevaluasi kekuatan hasil pengelasan serta kekerasan permukaan zona spesimen. Dengan menggunakan pendekatan eksperimental, pelat baja karbon rendah dipotong berbentuk alur V, dan disambung menggunakan las listrik SMAW. Data yang dikumpulkan melibatkan uji Tarik dan pengujian kekerasan di tiga zona pengelasan. Hasil menunjukkan bahwa panas yang dihasilkan arus listrik berdampak signifikan pada perubahan kekuatan dan kekerasannya. Kekuatan tarik tertinggi tercapai pada pengelasan dengan arus 120 A, dan nilai kekerasan bervariasi di masing-masing zona. Pada base metal (BM), tingkat kekerasan tertinggi pada pengelasan dengan arus 80 A dan elektroda berdiameter 2,6 mm. Sebaliknya, zona HAZ menunjukkan tingkat kekerasan maksimal spesimen dengan arus 120 A dan elektroda berdiameter 3,2 mm. Daerah weld metal (WM) mencapai tingkat kekerasan tertinggi spesimen dengan arus listrik 120 A dan elektroda berdiameter 3,2 mm.
Pemakaian Sistem Venturi Scrubber– EGR (Exhaust Gas Recirculation) Terhadap Performa Mesin Diesel Satu Silinder Samuel Parlindungan Siregar; Joni Joni; Obet Takke Ranteallo
G-Tech: Jurnal Teknologi Terapan Vol 8 No 2 (2024): G-Tech, Vol. 8 No. 2 April 2024
Publisher : Universitas Islam Raden Rahmat, Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33379/gtech.v8i2.4123

Abstract

Reusing exhaust gas based on potential energy that has not been completely burned can absorb heat in the combustion chamber thereby increasing the performance of diesel engines. The aim of this research is to determine the effect of using an EGR venturi scrubber on the performance of a single cylinder diesel engine. This research was carried out on a single cylinder diesel motorbike with a capacity of 200cc. Testing was carried out using an EGR venturi scrubber with valve variations of 10%, 20% and 30% compared to standard (0% EGR). Test data was obtained through VDAS technology software by loading the water entering the dynamometer at the test installation. The research results showed that testing using the EGR venturi scrubber on diesel motorbikes had an influence on engine performance. The best performance was obtained by using a venturi scrubber with a valve opening of 30%, where at a maximum rotation of 3000 rpm the torque was 6.57 Nm, the effective power was 2110 Watts, the average effective pressure was 4.72 bar, the specific fuel consumption was 0 .0549 kg/kWh, and a thermal efficiency of 58.42%.
Simulation Modeling of 140 MW CCGT Quality Indicators Based on DIN-VDI 4661 Standard Using Ebsilon® Professional Software Kaiway, Mickael Ruben; Giai, Agustinus; Griapon, Nourish Christin; Tosuli, Yohanis Tangke; Ranteallo, Obet Takke; Siregar, Samuel Parlindungan; Wanane, Yohanis Yulius; Pongsapan, Allo Sarira; Werdhani, Anastasia Sri; Palamba, Pither; Numberi, Johni Jonatan
G-Tech: Jurnal Teknologi Terapan Vol 9 No 2 (2025): G-Tech, Vol. 9 No. 2 April 2025
Publisher : Universitas Islam Raden Rahmat, Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.70609/gtech.v9i2.6614

Abstract

The operational efficiency of mid-capacity (140 MW) Combined Cycle Gas and Steam Power Plants (CCGT) remains underexplored concerning the DIN-VDI 4661 standard, which defines key quality metrics for energy systems. Addressing this gap is crucial for establishing standardized benchmarks to optimize performance and reduce energy losses. Existing studies mainly focus on Combined Cycle Gas Turbine (CCGT) units outside the 100–180 MW range and often do not explicitly follow DIN-VDI 4661, limiting efficiency comparisons and hindering targeted optimizations. This study simulates a 140 MW CCGT using Ebsilon® Professional software, incorporating DIN-VDI 4661 guidelines to assess eight quality indicators, including thermal efficiency, fuel utilization, and power-to-heat ratio. The model integrates gas and steam turbines, heat recovery, and auxiliary components, with input parameters validated against industry data. Energy balance analysis and sensitivity tests identified loss points. Results show a gas turbine thermal efficiency of 31.39%, steam turbine efficiency of 39.59%, and total system efficiency of 48.42%. However, significant energy losses (52% of input energy) were observed, mainly in gas turbines (87,000 kW) and steam turbines (56,000 kW). These findings highlight the need for design optimizations, such as improving heat recovery and turbine efficiency, to meet DIN-VDI 4661 benchmarks.