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Peningkatan Sifat Mekanik AISI 4130 Low Steel Alloy Melalui Perlakuan Panas Frista, Greida; Notonegoro, Hamdan Akbar; -, Hasanudin
FLYWHEEL : Jurnal Teknik Mesin Untirta Volume III Nomor 2, Oktober 2017
Publisher : Universitas Sultan Ageng Tirtayasa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36055/fwl.v2i1.2309

Abstract

Baja AISI 4130 merupakan baja paduan rendah (low steel alloy) yang mengandung kromium dan molibdenum. Baja ini memiliki sifat ulet atau daktil serta mempunyai faktor temperatur yang tinggi sehingga banyak digunakan dalam industri.  Pada bilah turbin exhaust AISI 4130 Low Steel Alloy yang dipasang pada unit boiler pembangkit listrik batubara, ditemukan terjadinya penipisan akibat bergesekan dengan partikel udara yang menabrak bilah saat berputar. Untuk mengatasi hal tersebut maka telah dilakukan usaha meningkatkan sifat mekaniknya dengan perlakuan panas melalui proses hardening dan tempering  selama 30 menit. Dari tiap proses tersebut¸ masing-masingnya di quenching dengan air dan oli. Dalam penelitian ini dibandingkan antara variasi suhu hardening 800 oC dan 900 oC dengan variasi suhu tempering 400 oC, 500 oC, dan 600 oC untuk memperoleh hasil perlakuan yang optimal. Hasil penelitian menunjukkan bahwa ketahanan aus yang optimal diperoleh dari proses hardening pada suhu 900 oC dan tempering pada suhu 500 oC. Proses ini akan menghasilkan AISI 4130 Low Steel Alloy yang lebih tahan keausan terhadap pengaruh lingkungan dan memiliki struktur martensite-bainite dengan kandungan ferrite yang tetap.
Diamagnetic to Ferromagnetic Like Transition of Non-Stoichiometry Barium Titanate (BaTiO3-x) Prepared by Sol-gel Method Soegijono, Bambang; Susetyo, Ferry Budhi; Notonegoro, Hamdan Akbar; Raksa, Teguh Yoga
Science and Technology Indonesia Vol. 9 No. 4 (2024): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2024.9.4.876-883

Abstract

The oxygen vacancy properties are significant, creating ferromagnetic properties of material in metal oxide systems like dilute magnetic semiconductors. An aqueous sol-gel method has been used in the present study to synthesize non-stoichiometry BaTiO3-x polycrystalline. In an attempt of examining the oxygen deficiency consequences on the magnetic properties, the gel samples were sintered (1000◦C) at various times (6, 12, 18, and 24 hours) under a vacuum environment. This study employs an X-ray diffraction apparatus in terms of characterizing segments and structures of the samples. It also investigates morphology and element distribution on the surface of the samples exploiting an Electron microscope where Energy dispersive spectroscopy is supplied. For the purpose of characterizing the magnetic properties of the samples, it applies vibrating sample magnetometers. The chemical state of the element and its corresponding bond to other elements was identified using X-ray photoelectron spectroscopy. Single-phase compounds were observed. The crystal system is tetragonal, but the crystal parameters are different. Increase sintering time leads to increase crystallite size and decrease in micro strain. Moreover, sintering in a vacuum environment results in oxygen deficiency and leads to the atomic ratio of Ba/Ti change as the sintering time increases. The Ba/Ti ratio change affects the transformation from diamagnetic to ferromagnetic-like. The elements (Ba, Ti and O) chemical state is shown and its bonding to the corresponding element along with the X-ray photoelectron spectroscopy pattern of the BTX2 sample. The element of oxygen binds to Ti and Ba while Ba element exists in two chemical states.
Raspberry-Pi Zero-Based Reflection Seismic Logger Design with Network Time Protocol Synchronization Suparno, Supriyanto; Notonegoro, Hamdan Akbar; Wicaksono, Britantyo; Akbar, Abdurrahman Azzam
FLYWHEEL : Jurnal Teknik Mesin Untirta Volume 8, Issue 2, October 2022
Publisher : Universitas Sultan Ageng Tirtayasa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36055/fwl.v0i0.17969

Abstract

Indonesia is a country with very high mineral reserve potential. The mining sector also contributes to non-tax state revenue. Efforts to explore the content of minerals in the earth's bowels can use the seismic reflection method. This seismological principle relies on the propagation of mechanical waves whose reflections are captured and recorded using a geophone. Limitations of domestically produced seismic instrumentation can slow down exploration activities.For this reason, developing domestic geo-seismic acquisition instrumentation is necessary to support exploration activities. In this study, eight units of a Raspberry Pi-based reflection seismic logger prototype device have been made using the MEMS ADXL355 accelerometer sensor with NTP protocol synchronization. Data from the initial test results show that the eight seismic reflection loggers of the device can work simultaneously in reading the seismic waves they receive.
Preparation, synthesis and characterizations of La0.7Sr0.3Mn(1-y)Ni(y)O3 alloy Setiawan, Jan; Susetyo, Ferry Budhi; Nanto, Dwi; Simbolon, Silviana; Notonegoro, Hamdan Akbar; Al Farizi, Taufiq; Yunasfi; Tihera, Dinda; Ramlan
Communications in Science and Technology Vol 9 No 1 (2024)
Publisher : Komunitas Ilmuwan dan Profesional Muslim Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21924/cst.9.1.2024.1361

Abstract

Nickel (Ni) doped in the perovskite manganite could result in superior properties. The effect of the Ni on the morphology, crystallographic orientation, and magnetic properties of La0.7Sr0.3Mn(1-y)Ni(y)O3 alloy (y = 0.1, 0.3, 0.5, and 0.7), therefore, was undertaken. La0.7Sr0.3Mn(1-y)Ni(y)O3 alloy was firstly processed using a ball milling process, and again processed through heat treatment and crushing at the end of the synthesis process. Powder alloy was then investigated using a scanning electron microscope equipped with scanning electron microscope and energy dispersive spectroscopy (SEM-EDS), x-ray diffraction (XRD), and vibrating sample magnetometer (VSM). The particle size became smaller and agglomerated as the amount of Ni doping increased. The polycrystal structure phase formed would become more complex when the Ni doping was 0.5 and 0.7, where the dominant phase formed was La2NiO4 even though the La0.7Sr0.3Mn(1-y)Ni(y)O3 phase was still formed. The magnetic characteristics showed that the Ni doping of 0.1 had a higher magnetization value around 4.2 emu/g at room temperature.
Layer Influence on Organosilica Composites Strength to Withstand the Impact of 9mm Caliber Bullets Notonegoro, Hamdan Akbar; Sofyan, Muhammad Azis; Rizkynawan, Benridho; Soegijono, Bambang; Setiawan, Jan; Aritonang, Sovian; Suherman, Andri; Ali, Nora'aini
Jurnal Sains Materi Indonesia Vol. 27 No. 1 (2025): Jurnal Sains dan Materi Indonesia
Publisher : BRIN Publishing (Penerbit BRIN)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/jsmi.2025.10243

Abstract

The use of steel panels in conventional bulletproof vests is no longer relevant to current needs. In addition to being heavy, troop flexibility is disrupted. It is necessary to develop lighter and more reliable composite panels. The purpose of this study was to determine the ability of organosilica resin composite panels that were given variations of 5, 7 and 9 layers of woven fiberglass to withstand 9 mm caliber bullets using the NIJ-0101.06 Standard. The results of the firing test showed that the bullets were held back in the 7th and 9th layers. This result shows that this composite is a worthy candidate to replace conventional steel panels in bulletproof vests.
Fatigue Characteritics of Medium Carbon Steel after Heat Treatment Using Sand as Cooling Media Sunardi, Sunardi; Randu, Randu; Listijorini, Erny; Saefuloh, Iman; Notonegoro, Hamdan Akbar; Jannah, Miftahul
INTEK: Jurnal Penelitian Vol 8 No 2 (2021): October 2021
Publisher : Politeknik Negeri Ujung Pandang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31963/intek.v8i2.2817

Abstract

Stress concentrations cause many machine element failures. Failure will occur more rapidly if the machine elements obtain repeated and fluctuating loading. For this reason, the material for machine elements must have better fatigue life. There are various attempts made to increase material life and other mechanical properties. In this study, the research sample used is AISI 4140 steel. The samples obtain hardening followed by cooling and tempering. The hardening temperature is 8500C with a holding time of 17 minutes. The cooling media in this research are dry sand, semi-wet sand, and wet sand. Wet measurements based on volumetric ratios. Semi-wet sand with a ratio of sand and water 4: 1, sandy sand 4: 2. The final process is tempering treatment, with a temperature of 2500C. The material fatigue test refers to the JIS Z 2274 Standard. From this study, the heat treatment given can reduce the fatigue life of the material, even though the hardness increases. The higher the cooling rate, the hardness of the material increases, but the fatigue life is low.