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Combustion Analysis of Ammonia/Gasoline Mixtures at Various Injection Timing Conditions in a High Compression Ratio SI Engine with Sub-Chamber Ichiyanagi, Mitsuhisa; Yilmaz, Emir; Suzuki, Takashi; Okada, Takanobu; Yamamoto, Hikaru; Kodaka, Masashi; Shiraishi, Hikaru; Mukae, Shinnosuke; Tamba, Ryota; Widjaja, Henry; Jonathan, Leon; Gunawan, Sebastian; Gotama, Gabriel Jeremy; Anggono, Willyanto
Automotive Experiences Vol 7 No 2 (2024)
Publisher : Automotive Laboratory of Universitas Muhammadiyah Magelang in collaboration with Association of Indonesian Vocational Educators (AIVE)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31603/ae.10533

Abstract

Due to the problem of carbon dioxide (CO2) emissions, alternative fuels such as ammonia (NH3) have garnered a lot of attention lately. This is due to its carbon-free molecular structure, ease of transport, and high energy density. Unfortunately, ammonia is not without flaws since it is considered a difficult fuel to burn in conventional internal combustion engines. To further investigate the burning characteristics of ammonia, this study is conducted for ammonia/gasoline co-combustion using a modified engine equipped with a sub-chamber. The engine ran at 1000 RPM and had a 17.7 compression ratio with two injection timings of -55 and 10 crank angle degrees (°CA) after the top dead center (ATDC), while the ammonia energy ratios were adjusted across a range from 40% to 70%. The results show that the earlier injection timing allowed better premixing between the air and fuel mixture, thus enhancing the overall combustion characteristics. For the later injection timing, the nitrogen oxide (NOx) emissions decrease at the higher ammonia energy ratio due to the denitrification of the nitrogen oxides (DeNOX) process. Overall, the earlier injection timing appears optimal for the 40% to 70% ammonia energy ratio under the present condition.
Pengabdian Masyarakat Sosialisasi Metris Vertikal Cara Berhitung Lebih Bervariasi Goenawan, Stephanus Ivan; Prasetya, Wibawa; Kurniawan, Angela Arella; Gunawan, Sebastian
Jurnal Pengabdian Masyarakat Charitas Vol. 4 No. 01 (2024): Jurnal Pengabdian Masyarakat Charitas Juni 2024
Publisher : Program Studi Teknik Industri, Fakultas Teknik, Universitas Katolik Indonesia Atma Jaya Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25170/charitas.v4i01.5495

Abstract

Logical abilities and creativity in calculations can be applied in economics where people organize and manage a business activity themselves and bear the risks of their business. He is responsible for his business, financial risks, material and human resources in his business. Technical economists usually act as owners or managers and also as operators of their business activities. Calculation in technical economics is a science that contains how to calculate, how to make considerations in solving a problem, including the feasibility of a business with existing alternatives based on economic factors and criteria. By studying this approach, it is hoped that someone can make the best decision from the many available alternatives. From the description of arithmetic it can be seen that calculations in technical economics involve very technical considerations. So technical economics involves technical analysis, with emphasis on economic aspects and has the aim of assisting decision making. Therefore, in making the decision to do so, a technical economist must be able to make the right decision. The right decision is not a decision without consideration. Of course, to make the right decision, basic considerations are needed. These basics are what are called alternatives in making decisions. This process of many alternatives can be tried to simulate through learning arithmetic calculations which can be done in various or many ways using the vertical metris method.
Forecasting Methods Proposal and Implementation of Distribution Requirement Planning Method to Overcome Unfulfilled Stock Availability at PT. XYZ Natalia, Christine; Gunawan, Sebastian; Liang, Yun Chia; Sugioko, Andre; Tripiawan, Wawan; Fredikson, Marcelinus
Jurnal Asiimetrik: Jurnal Ilmiah Rekayasa & Inovasi Volume 7 Number 1 (2025)
Publisher : Fakultas Teknik Universitas Pancasila

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35814/asiimetrik.v7i1.7314

Abstract

PT. XYZ is a manufacturing company engaged in the automotive sector by producing various automotive components. Based on the results of observations and interviews at PT. XYZ, it is known that there is a shortage of stock, so that customer or consumer requests are not fulfilled at each existing distribution center (DC). Based on the problems that occur, the research result suggestions for the best forecasting method based on the time series plot of each DC request processing using the Distribution Requirement Planning (DRP) method. In addition, with the DRP method, there is additional stock. The company still has remaining stock so it can still meet customer demand for each DC, and the product distribution process runs more regularly if any defective product should be replaced. Based on research results, the DRP method is able to minimize the risk of unfulfilled demand due to product defects.