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All Journal Infotekmesin Saintara : Jurnal Ilmiah Ilmu-Ilmu Maritim Euler : Jurnal Ilmiah Matematika, Sains dan Teknologi Jurnal Maritim Polimarin Jurnal Ilmu dan Inovasi Fisika Karunia: Jurnal Hasil Pengabdian Masyarakat Indonesia
Ngatmin Ngatmin
Politeknik Maritim Negeri Indonesia
Agriculture, Biological Sciences & Forestry Humanities Computer Science & IT Control & Systems Engineering Economics, Econometrics & Finance Education Electrical & Electronics Engineering Energy Engineering Environmental Science Health Professions Industrial & Manufacturing Engineering Languange, Linguistic, Communication & Media Law, Crime, Criminology & Criminal Justice Library & Information Science Materials Science & Nanotechnology Mathematics Mechanical Engineering Physics Social Sciences Transportation

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Pengaruh Tiram pada Lambung Kapal Terhadap Benaman Kapal Sebelum dan Sesudah Dok (Studi Kasus Pelabuhan Tanjung Emas Semarang) Susanto Susanto; Ngatmin Ngatmin
Jurnal Maritim Polimarin Vol. 3 No. 1 (2017)
Publisher : PPPM Polimarin

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Tiram hidup dengan cara menempel, salah satu tempat yang disukai untuk hidup adalah di lambung kapal. Tiram yang menempel di lambung kapal diindikasikan  mempengaruhi pengoperasian kapal dan berat benaman kapal. Penempelan tiram di lambung kapal membuat permukaan lambung kapal menjadi tidak halus dan tidak rata dan selanjutnya dapat menyebabkan gesekan yang lebih besar, sehingga akan berpengaruh langsung terhadap kecepatan. Dengan jumlah populasi tiram yang banyak pada lambung kapal kemungkinan akan menambah berat benaman kapal. Penelitian tentang Pengaruh Tiram Pada Lambung Kapal Terhadap Benaman Kapal Sebelum Dan Sesudah Dok merupakan penelitian studi kasus di Pelabuhan Tanjung Emas ). Studi kasus dilakukan terhadap kapal yang sedang melakukan dry dock dan melakukan pembersihan lambung kapal. Teknik pengumpulan datanya dengan observasi lapangan, wawancara dan diskusi dengan pihak-pihak terkait yang meliputi awak kapal yang berhubungan langsung dengan pengoperasian kapal serta pekerja dock yang menangangi tiram yang menempel dilambung kapal saat dry dock. Temuan yang diperoleh adalah bahwa akibat-akibat yang ditimbulkan dari penempelan tiram di lambung kapal tersebut secara umum mempengaruhi pengoperasian kapal. Permukaan lambung yang banyak ditempeli tiram berpengaruh terhadap kecepatan dan kestabilan kapal saat berlayar. Untuk pengaruhnya terhadap berat benaman tidak begitu signifikan jika dibandingkan dengan berat kapal yang mencapai ribuan ton.
Analisis Gugus Fungsi, Morfologi dan Ukuran Partikel Manganese Ferrite yang Disintesis dari Pasir Besi Heri Kiswanto; Indah Nurhidayati; Ario Hendartono; Prijo Harsono; Ngatmin Ngatmin
JIIF (Jurnal Ilmu dan Inovasi Fisika) Vol 7, No 2 (2023)
Publisher : Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/jiif.v7i2.47022

Abstract

Manganese ferrite (Mn ferrite) telah berhasil disintesis dengan metode kopresipitasi pada suhu 60 ℃. Mn ferrite disintesis dari pasir besi sebagai prekusornya. Tujuan dari penelitian ini untuk mensintesis Mn ferrite dari pasir besi dan menganalisis gugus fungsi serta morfologinya. Sampel dibuat dengan memvariasikan NaOH yaitu 3 M, 6 M dan 9 M. Struktur kristal, gugus fungsi dan morfologi dikarakterisasi dengan X-ray Difractometer (XRD), Fourier Transform Infra Red (FTIR), dan Transmission Electron Microscopy (TEM). Hasil spektra FTIR mengkonfirmasi adanya gugus fungsi metal-oxide (M-O) pada kisi tetrahedral dan oktahedral pada bilangan gelombang masing-masing 462 cm-1 dan 578 cm-1. Hal ini diidetifikasi sebagai gugus Mn-O dan Fe-O sekaligus mengkonfirmasi pembentukan struktur spinel. Pengamatan morfologi menunjukkan bahwa sampel terlihat mengalami aglomerasi karena adanya interaksi magnetik. Hasil pengamatan ukuran partikel berada pada kisaran 30 – 50 nm yang diukur menggunakan software Image-J. Ukuran butir terlihat lebih besar dibandingkan hasil perhitungan ukuran kristalit berdasarkan data XRD karena sampel mengalami aglomerasi sehingga beberapa butir menggumpal menjadi satu dan terlihat seperti satu partikel.Kata kunci: Mn-ferrite, gugus fungsi, morfologi, ukuran partikel
Pengaruh Perubahan Vakum dan Temperatur Pemanas Fresh Water Generator terhadap Produksi Air Tawar di MT. PM REGENT Susanto Susanto; Khaeroman; Yulius Oscar; Ngatmin Ngatmin; Heri Kiswanto
Saintara: Jurnal Ilmiah Ilmu-Ilmu Maritim Vol 8 No 2 (2024): SAINTARA (September 2024)
Publisher : Lembaga Penelitian dan Pengabdian kepada Masyarakat, Akademi Maritim Nusantara Cilacap

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.52475/saintara.v8i2.343

Abstract

Fresh onboard water is required to fulfill the crew's living needs and support the ship's operations. The need for fresh water for the crew and operational support of the boat is fulfilled with fresh water purchased from the land. Water purchases can be made when the ship is in port, either when the ship is at the dock or when the boat is anchored. Additional fresh water supply can be obtained continuously while the ship is sailing. Seawater desalination is a solution to produce fresh water to fulfill the new water needs. Desalination using a freshwater generator (FWG) involves evaporation and condensation processes affected by vacuum and operating temperature. This study was conducted to determine the effect of changes in pressure and temperature parameters on the production capacity of the freshwater generator. The study was conducted using a case study method through observation, and experimentation on board MT.PM REGENT. The vacuum in the FWG chamber was varied based on the suction of the vacuum ejector. Hot water temperature as a heater in the evaporator is taken from the cooling jacket of the main engine. The result of the pump ejector pressure variation greatly affects the vacuum level of the distillation chamber At pump ejector pressures between 8 – 16 Bar, the vacuum rate can reach 99 – 100% after the pump is operated At pressures of 2 and 4 Bar, the vacuum level drops dramatically, reaching only 50 and 80 %, respectively. The lowest production of FWG when operated with 80% vacuum with a heating temperature of 75 OC is 2767 liters/day. In FWG operation with a maximum vacuum of 100% and a heating temperature of 85 OC, it is able to produce the most fresh water around 6879 liters/day. Based on the changes in parameters, it can be concluded that a decrease in the level of vacuum and heater temperature reduces the production of fresh water from the Fresh Water Generator.
Pemodelan Graf Berarah Berbobot untuk Optimasi Penentuan Rute Terpendek Antar Kampus Polimarin Berbasis Algoritma Dijkstra Helena Devi Ariyani; Khoirotun Nafillah; Kirtyana Nindita; Ngatmin Ngatmin; Sri Tutie Rahayu
Euler : Jurnal Ilmiah Matematika, Sains dan Teknologi Volume 14 Issue 1 April 2026
Publisher : Universitas Negeri Gorontalo

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.37905/euler.v14i1.37524

Abstract

The mobility of academicians between the two geographically separated campuses of the Indonesian Maritime State Polytechnic (Polimarin), namely Campus 1 Ungaran and Campus 2 Bendan Duwur Semarang, creates travel efficiency issues due to numerous unmeasured route alternatives. This study aims to model the inter-campus road network as a weighted directed graph and apply the Dijkstra algorithm to determine the shortest route accurately and verifiably. The research employs an applied computational approach using actual distance data obtained from Google Maps (driving mode), collected on August 22, 2024, at 09:00 WIB to represent traffic conditions at that time. The process includes node identification (strategic locations), edge formation (connecting road segments), and weight assignment based on actual distances, resulting in a graph with 9 nodes and 10 edges. The iteration process is conducted in 8 steps by evaluating the minimum accumulated weight at each stage. The results indicate that the shortest path is A → B → E → G → H → I, passing through Jl. PTP Ngobo, Jl. Diponegoro–Jl. Slamet Riyadi, Jl. Moh. Yamin–Jl. Ahmad Yani, and Jl. Gatot Subroto, with a total distance of 25.80 km out of 11 possible routes. These findings demonstrate that the Dijkstra algorithm is effective for route optimization by eliminating inefficient paths through cumulative weight evaluation. Validation is performed by comparing the algorithm’s results with Google Maps recommendations based on travel distance. However, this study is limited to static data, and further development is required through the integration of dynamic traffic data.
Analisis Penyebab Penurunan Temperatur Pada Sistem Permesinan di Kapal Wahyu Ari Putranto; Shendi May Rudin; Yulius Oscar; Khaeroman Khaeroman; Noviarianto Noviarianto; Ngatmin Ngatmin
Jurnal Maritim Polimarin Vol. 12 No. 1 (2026)
Publisher : PPPM Polimarin

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.52492/jmp.v12i1.176

Abstract

Marine generators play a crucial role in supplying electrical power for overall ship operations. This study aims to investigate the factors causing the temperature drop in the Marine Fuel Oil (MFO) system of the generator on MV. Radiant Reb. The temperature decrease (to 98ºC-100ºC) leads to increased fuel viscosity, flow resistance, and a decline in both combustion efficiency and diesel generator performance. By applying a descriptive-qualitative case study approach involving direct observation, interviews, and documentation, this research identified four primary causes. These factors include: reduced heater performance due to scaling and leaks, a suboptimal steam trap causing condensate buildup, damaged thermal insulation (lagging) accelerating heat loss, and wear on the circulation pump disrupting fuel flow. Corrective measures were implemented through routine maintenance and thorough inspections of these vital components. In conclusion, preventive maintenance and early detection are crucial for maintaining the fuel temperature within the ideal range (108ºC-118ºC) to preserve the operational efficiency and reliability of the marine generator.
Analisis Proses FSW dan PWHT Material Aluminium Terhadap Kekuatan Tarik, Kekerasan dan Mikrostruktur Wahyu Ari Putranto; Khaeroman Khaeroman; Heri Kiswanto; Ngatmin Ngatmin; Prijo Harsono; Purwanto Purwanto
Infotekmesin Vol 17 No 2 (2026): Infotekmesin: Juli 2026
Publisher : P3M Politeknik Negeri Cilacap

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35970/

Abstract

Friction Stir Welding (FSW) is a welding method that does not use filler materials. FSW has been widely used in the maritime industry. The purpose of this study is to analyze the effect of FSW joints before and after Post Weld Heat Treatment (PWHT) on 5052 and 6061 aluminum alloy materials. The FSW parameters include a spindle speed of 1500 rpm (clockwise), a travel speed of 30 mm/min, a tool depth of 0.2 mm, and a tool tilt angle of 1°. The PWHT parameters involve heating the FSW material to 550°C, with holding times of 45 and 90 minutes, followed by water quenching. The subsequent process is artificial aging up to a temperature of 200°C for 6 hours. The materials were then subjected to tensile testing, hardness testing, and micrographic examination. The results showed that the highest values were achieved using FSW parameters with 90 minutes of PWHT, yielding the maximum tensile strength and hardness values of 264 MPa (27.5%) and 89.6 HV (37.4%). Furthermore, the smallest and most uniform grain size was quantitatively observed at 4.9 µm in both the weld zone and the base metal.
Meningkatkan Peran Aktif Karang Taruna dalam Meningkatkan Kesejahteraan Sosial untuk Menyongsong Indonesia Emas Tahun 2045 Susanto Susanto; Gunawan Budi Santoso; Ngatmin Ngatmin; Juwarlan Juwarlan; Prijo Harsono; Amthori Anwar
Karunia: Jurnal Hasil Pengabdian Masyarakat Indonesia Vol. 5 No. 1 (2026): Maret : Karunia: Jurnal Hasil Pengabdian Masyarakat Indonesia
Publisher : Fakultas Teknik Universitas Maritim AMNI Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.58192/karunia.v5i1.4160

Abstract

Abstract and The Community Service Program (PKM) implemented by lecturers from the Indonesian State Maritime Polytechnic in partnership with the Karang Taruna Youth Association of RW 03, Genuk Village, Semarang Regency, aims to strengthen the capacity of youth organizations to improve social welfare. As a forum for the younger generation, Karang Taruna often faces issues related to governance, low social participation, and limited productive skills. The PKM implementation method employs a problem-based approach through the stages of survey, situation analysis, solution formulation, training, and evaluation. Key activities include training in organizational governance, character building through moral values, Sinoman, and Pranoto Coro, as well as vocational skills in electric welding. The results of the activities showed significant improvements across various aspects: organizational governance increased from 30% to 85%, social awareness of mutual cooperation rose from 40% to 90%, pranoto coro skills reached 70%, electrical welding skills reached 75%, active member participation rose from 25% to 80%, and initiatives for productive activities increased from 5% to 65%. These findings confirm that the PKM program serves not only as a knowledge transfer initiative but also as a catalyst for social and economic change. The provision of technical skills opens opportunities for productive enterprises, while the reinforcement of cultural values strengthens social solidarity. Thus, this PKM program contributes to strengthening the strategic role of Karang Taruna as a driving force for social development, while also underscoring the importance of collaboration between higher education institutions and the community in advancing Indonesia’s vision for 2045.
Co-Authors Anwar, Amthori Ario Hendartono Gunawan Budi Santoso Helena Devi Ariyani Heri Kiswanto Heri Kiswanto Indah Nurhidayati Juwarlan Juwarlan Khaeroman, Khaeroman Khoirotun Nafillah Kirtyana Nindita Noviarianto, Noviarianto Prijo Harsono Purwanto Shendi May Rudin Sri Tutie Rahayu Susanto Susanto Wahyu Ari Putranto Yulius Oscar