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Jaka Fajar Fatriansyah
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Journal of Materials Exploration and Findings
Published by Universitas Indonesia
ISSN : -     EISSN : 29625475     DOI : https://doi.org/10.7454/jmef
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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 6 Documents
 1 
Search results for , issue "Vol. 4, No. 1" : 6 Documents clear
Ultimate Limit State Reliability-Based Approach Life Prediction of an Existing Frame Structure Under Seismic Hazard in Indonesia Herucakra, Wira; Adnyani, Luh Putri
Journal of Materials Exploration and Findings Vol. 4, No. 1
Publisher : UI Scholars Hub

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Abstract

Life assessment integrated with Structural Integrity Management (SIM) has been implemented in the oil and gas industry for the past decade to maintain the integrity and safety of an in-service structure used to support hydrocarbon exploration, production, and processing activity. Current structural life assessment, as ruled by the American Petroleum Institute (API), uses a fatigue-based approach for offshore structures subjected to wave loading. As the general principle of SIM is not limited to offshore structures, this study offers an alternative life assessment method for onshore structures, especially steel frame structures subjected to earthquake loads. Reliability analysis, combined with the effect of the time-related degradation mechanism of steel structure due to corrosion and mechanical damage, with non-linear structural analysis, produces comprehensive ultimate limit state behaviour and performance of an existing structure. A steel frame structure located in Indonesia was evaluated in this study, with the reference base shear developed based on the latest Indonesian Seismic Provision SNI 1726-2019; the life of the structure was estimated by determining the time interval required for the overstrength factor produced from the pushover analysis to approximate 1.0. The assessment demonstrated that the life of the existing structure exceeds its design life and is safe for operation.
Spin Coater Design with PID Algorithm Using Polynomial Regression Approach and Bias Tuning for TiO2 Deposition Process Andika, Geo Surya; Sofyan, Nofrijon; Dhaneswara, Donanta; Yuwono, Akhmad Herman
Journal of Materials Exploration and Findings Vol. 4, No. 1
Publisher : UI Scholars Hub

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Abstract

The thin-film deposition technique using spin coating offers a cost-effective alternative to Chemical Vapor Deposition (CVD) and Physical Vapor Deposition (PVD). The spin-coating process requires precise control of the motor drive system to ensure that the rotational speed, measured in rotations per minute (RPM), aligns with the set point and remains stable. This study presents the design and development of a spin coater prototype to achieve uniform thin-film deposition. The control method employed utilizes a Proportional-Integral-Derivative (PID) algorithm, incorporating a polynomial approach with bias tuning. The PID control was chosen to achieve stable operation in a non-linear system. The performance of the non-linear PID control system is compared with an open-loop control system by evaluating the overshoot behavior. In the first experiment, a proximity sensor was tested to measure the spin coater motor's speed in an open-loop control configuration. The performance was evaluated using Mean Absolute Error (MAE) and Mean Absolute Percentage Error (MAPE) metrics, with results showing an MAE of 1358.6 RPM and a MAPE of 23.13% compared to a tachometer. In the second experiment, step-response testing was conducted using a closed-loop PID control system with a polynomial approach and bias tuning. Compared to the open-loop system, the closed-loop PID controller reduced overshoot to less than 3%. The RPM deviation between the spin coater and the tachometer was limited to range, approaching ideal conditions. The closed-loop control was tested within the 5000–9000 RPM range, where stable RPM regulation resulted in more uniform TiO2 thin-film distribution on glass substrates. This study highlights the effectiveness of closed-loop PID control in achieving precise rotational control, which is essential for enhancing the quality of thin-film deposition.
Remaining Life Analysis of Pipeline Gas with Extreme Value Theory Simeon, Rony Prayitno; Siradj, Eddy Sumarno; Kurniawan, Tedi
Journal of Materials Exploration and Findings Vol. 4, No. 1
Publisher : UI Scholars Hub

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Abstract

Energy and chemical companies use pipelines to transfer oil, gas, and other materials from one place to another, within and between their plants. Pipeline integrity is an important concern because pipeline leakage could result in serious economic or environmental losses. Some research has applied to understand the effect of extrapolation value of the minimum thickness of pipeline by using the Extreme Value Theory. In this research, both statistical models and Extreme Value methods were applied and developed for the reliability of the pipeline by assuming the constant corrosion rate and deviation due to measuring devices were neglected. The research obtained that using the General Pareto Distribution technique, the result found that the extreme value method seems not close agreement with the Pareto Distribution. While using the Generalized Extreme Value Technique found remaining life of 344 blocks data of the pipeline around 5.23 years. It could be suggested that next pipeline pigging should be conducted within 2.5 years.
Assessment of H2S-Induced Cracking Susceptibility in Steam Line Pipes and Weld Zones During Geothermal Well Construction Pragitta, Riene Kaelamanda; Pratesa, Yudha
Journal of Materials Exploration and Findings Vol. 4, No. 1
Publisher : UI Scholars Hub

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Abstract

The susceptibility of steam line pipes, especially in the HAZ (heat-affected zone) and weldment areas, to hydrogen sulfide in the geothermal industry is crucial to understand from the early stages, particularly during construction. The combination of tensile stress from residual stresses after welding and metallurgical phase transformation makes the joint areas vulnerable to sulfide stress cracking. This condition becomes even more extreme when the equipment operates during the well stimulation phase. This research assesses the severity of H₂S-induced cracking using NACE MR0175 and ISO 15156-1 standards, focusing on the effects of pH and partial pressure of H₂S (pH₂S). The findings aim to provide insights into critical factors influencing H₂S cracking susceptibility and to enhance material integrity in geothermal systems. The result shows that while A106 Gr B steel generally meets sour service requirements, certain nodes within the geothermal facility exhibit a moderate risk of cracking under transient conditions. These results emphasize the importance of controlling fluid composition and implementing proper welding procedures to mitigate sulfide stress cracking (SSC).
Integrity Assessment of Shipping Line Pipelines Using Risk-Based Analysis to Determine Risk and Maintenance Strategies Anggraini, Ade Ratih; Nurjaya, Dwi Marta
Journal of Materials Exploration and Findings Vol. 4, No. 1
Publisher : UI Scholars Hub

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Abstract

Pipeline Shipping Lines X, Y & Z are classified as critical infrastructure, being the only transportation through the crude oil lifting from P and R location to the transfer station in NM Area. To maintain the workflow of the Shipping Line, integrity assessments and risk evaluation are required to ensure the operational and safety. Anomalies were found by analysing inspection, monitoring, and repair data, while the pipelines' future integrity was assessed by calculating the remaining life. Risk-Based Analysis (RBA), which is a modification of Kent Muhlbaeur's method, is employed to conduct the risk assessment using the Probability of Failure (POF) and Consequence of Failure (COF) in order to develop the risk profile. Simulations of pressure built up, temperature drop, and wax deposition are performed through flow assurance analysis to predict the Shipping Line condition. The results of the integrity assessment show that the Shipping Lines X, Y, and Z is fit-for-service. Nevertheless, some concerns need to be addressed, including active internal degradation mechanisms such as Under Deposit Corrosion (UDC) and Microbiologically Induced Corrosion (MIC), as well as active external threats such as Corrosion Under Insulation (CUI). The result of integrity and risk assessment Shipping Lines X, Y, and Z are crucial for planning inspection schedules and maintenance strategies in short, medium, and long term.
Characteristics of Carbonaceous Materials Synthesized from Palm Oil Empty Fruit Bunch Waste Using Ferrocene Catalyst Shahab, Ahmad Nabil; Islam, Adinda Izzatul; Wardana, Afif; Yahya, Ilham Nur Dimas; Amalia, Ary Yanuar Tri; Sofyan, Nofrijon; Dhaneswara, Donanta
Journal of Materials Exploration and Findings Vol. 4, No. 1
Publisher : UI Scholars Hub

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Abstract

The synthesis of carbonaceous materials for reduced graphene oxide (rGO) precursors using oil palm empty fruit bunches waste as a carbon source offers a sustainable solution for waste management in the palm oil industry while delivering high-performance materials. The oil palm empty fruit bunches were carbonized, followed by acid washing, pyrolysis with ferrocene (8%, 12%, and 16% variations), and ultrasonication to produce rGO. The structural, electronic, and morphological properties of the rGO were analyzed using various characterization techniques. The band gap values decreased with increasing ferrocene concentration, from 1.14 eV (8%) to 1.06 (16%), indicating enhanced electronic conductivity. XRD analysis revealed a crystal size increase from 11.3 nm (8%) to 181 nm (16%), while Raman spectroscopy showed a consistent D to G intensity ratio of 0.85, indicating reduced structural defects. SEM-EDS results demonstrated a carbon to oxygen atomic ratio of 4.38 (8%), 3.79 (12%), and 3.77 (16%), confirming successful reduction and improved carbon content. These finding highlight the potential of rGO synthesized from oil palm empty fruit bunches for applications in semiconductors, energy storage, and gas sensing, offering an innovative approach to sustainable materials development.

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