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Journal of Materials Exploration and Findings
Published by Universitas Indonesia
ISSN : -     EISSN : 29625475     DOI : https://doi.org/10.7454/jmef
Core Subject :
JMEF publishes publications that report on R&D discoveries and fundamental understanding of phenomena with potential significance, as well as those that explore solutions to current engineering challenges in materials and mechanical engineering or related fields. JMEF includes original research, review and short communication articles. JMEF welcomes original articles on all aspects of materials science/engineering and mechanical engineering, including: 1. Materials synthesis, processing and manufacturing; 2. Advanced Materials; 3. Extraction metallurgy; 4. Physics of Materials; 5. Computational studies on Materials and Mechanical Engineering; 6. Fluid Dynamics and Heat Transfer; 7. Management Integrity and Reliability Engineering; 8. Mechanical systems; and related fields.
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Articles 5 Documents
 1 
Search results for , issue "Vol. 2, No. 3" : 5 Documents clear
Combined Risk Based Inspection and Fault Tree Analysis for Repetitive 3-Phase Line Piping Leakage at West Java Offshore Topside Facility Yuliati, Dona; Yuwono, Akhmad Herman; Asral, D. Rizal; Dhaneswara, Donanta
Journal of Materials Exploration and Findings Vol. 2, No. 3
Publisher : UI Scholars Hub

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Abstract

Hydrocarbon releases might result in serious consequences in various aspects. In addition to the contribution to environmental pollution, repetitive leakages need high repair costs. This study aim is to minimize potential repetitive leakage for other typical 3-phase piping systems. We conducted the risk assessment by adopting Risk Based Inspection (RBI) API 581 to identify risk level, calculating piping lifetime, recommended inspection plan and mitigations. The most relevant root causes can be obtained through quantitative Fault Tree Analysis (FTA). Observation and investigation was taken from eight 3-phase piping systems that experienced repetitive leakages. It has been found that the risk level of some piping systems in yellow and red areas with one pipe in an unfit condition. Next inspection and/or mitigation dates as results of RBI calculation shall be conducted to reduce risk levels and prevent leakage cases. FTA shows the most likely events are the sand problem in fluid, high CO2 content, material deficiency, and high fluid velocity. If the root causes are known earlier, preventive mitigation can be conducted to prevent hydrocarbon release in the other 3-phase piping systems, such as application of internal coating, injection corrosion inhibitor or inspection/monitoring program.
The Effect of Parameters in Cryogenic Treatment on Mechanical Properties of Tool Steel: A Review Ekaputra, Ronaldus Caesariano; Mochtar, Myrna Ariati
Journal of Materials Exploration and Findings Vol. 2, No. 3
Publisher : UI Scholars Hub

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Abstract

Tool steel is classified as special alloy steel which proposed as dies or mold materials as their high mechanical properties and dimensional stability. In order to improve tool steel’s mechanical properties, heat treatment process, especially, cryogenic treatment is conducted. Cryogenic treatment is done by exposing tool steel material at sub-zero liquid/gas media after heated at austenite temperature. This process significantly affects the martensite phase transformation increase and avoids retained austenite emersion. In particular, the higher martensite volume fraction, the higher hardness and wear resistance value of tool steel. It had been proven that adjusting critical process parameters of cryogenic treatment (temperature process, soaking period, and tempering process) shall increase the efficiency of improving mechanical properties of cryo-treated finished product.
Characteristics of Sodium Lithium Titanate Synthesized at Different Solid-State Reaction Temperature for Lithium-Ion Battery Anode Yahya, Ilham Nur Dimas; Sofyan, Nofrijon; Khaerudini, Deni Shidqi; Timuda, Gerald Ensang; Priyono, Slamet
Journal of Materials Exploration and Findings Vol. 2, No. 3
Publisher : UI Scholars Hub

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Abstract

The effect of sintering temperature on the characteristics of sodium lithium titanate (NaLiTi3O7/NaLTO) synthesized at different solid-state reaction temperature and its performance as lithium-ion battery anode has been investigated. The precursors for the synthesis consisted of LiOH.H2O, TiO2, and NaHCO3. The synthesis was performed via solid-state reaction method. The precursors were mixed and sintered at variation temperatures of 900oC, 1000oC, and 1100oC for 2 hours under atmosphere condition. The final product was characterized using X-ray diffraction (XRD) and particle size analyzer (PSA). The XRD analysis showed the main phase of NaLTO with some impurities. PSA analysis showed that the sintering temperature has a significant effect on changes in particle size where the sample at a temperature of 1100oC has the largest particle size of 74.62 µm. The battery was fabricated by firstly mixing NaLTO powder with polyvinylidene fluoride (PVDF) and acetylene black (AB) in a ratio of 85:10:5 wt.% and the mix was then deposited onto copper foil to form NaLTO a sheet. The NaLTO sheet was cut into circular discs with a diameter of 14 mm and were arranged in a sequence of separator, metallic lithium, and electrolyte to form a coin cell in a glove box. Characterization using cyclic voltammetry (CV) and charge-discharge (CD) showed that the NaLTO sintered at 1000oC provided good electrochemical performance with the largest diffusion coefficient of 3.948 x 10-10 m2/s, Coulombic efficiency reached 100%, and a high specific capacity of 65.83 mAh/g.
Nitrogen Gas Quenching Pressure Effect on Bs S155 Alloy Steel in Vacuum Furnace Hasanudin, Agus Mulyadi; Siradj, Eddy Sumarno
Journal of Materials Exploration and Findings Vol. 2, No. 3
Publisher : UI Scholars Hub

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Abstract

The production of metal and alloy products requires the use of heat treatment, when during the heat treatment process, quenching is a crucial step. The quenching medium can be anything from water, a salt bath, oil, air and gas. In a vacuum furnace, pressurized gas, most frequently nitrogen (N2) gas, serves as one of the quenching mediums. One of the drawbacks of the quenching process is the distortion and dimensional change of the parts. This paper aims to investigate the influence of nitrogen gas quenching pressure on the distortion and dimensional change of aerospace actuator gear planet parts made from BS S155 alloy steel. BS S155 is the British aerospace equivalent of U.S. steel grade 300M (4340M), it is a vacuum melted grade supplied in the normalized and softened condition to allow for final heat treatment and widely used such as undercarriage components, gears, and shafts. Gear planet parts heat treated and quenched with pressurized nitrogen gas as an independent variable of the experiment, then double temper as required on the specification. Following this, optical microscopes, tensile and hardness tests in accordance with ASTM E8 and ASTM E92, as well as dimensional analysis, were used to characterize the parts. The results demonstrate that nitrogen gas quenching at 1.5 bar pressure improves dimensional stability without degrading the mechanical properties of the part, with the maximum dimensional distortion being 0.06% or 20 µm, while the mechanical properties result for the two nitrogen gas quenching pressures were less significantly different.
Pipeline Risk Analysis Optimization with Monte Carlo Method Using Gamma Distribution Digita, Farhan Rama; Fatriansyah, Jaka Fajar; Ridzuan, Abdul Rahim; Ovelia, Hanna; Mas'ud, Imam Abdillah; Tihara, Irma Hartia; Linuwih, Baiq Diffa Pakarti
Journal of Materials Exploration and Findings Vol. 2, No. 3
Publisher : UI Scholars Hub

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Abstract

The inspection process of piping components in the oil and gas industry is one of the most crucial things, given the high risk posed by pipeline system failures, which have a huge impact on losses, both from environmental and financial aspects. Risk-based inspection with the Monte Carlo method is one of the efforts that can be made to minimize failures in piping systems, by involving data distribution to calculate the probability of component failure. Although the normal distribution is commonly used for generating random variables, its use in corrosion rate calculation can lead to overestimation due to negative corrosion rate values. Overestimation can result in inaccurate data and higher risk values, which can cause increased inspection costs. Therefore, the use of gamma distribution as a random variable generator can be a solution to reduce the bias level and increase the accuracy of the normal distribution analysis results. The gamma distribution is proven to prevent overestimation, so it can avoid inspection cost losses because the resulting risk value is lower than the normal distribution.

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