Recent in Engineering Science and Technology

CLIMATE CHANGE – GREEN BLAST FURNACES

Nicholas Standish — 2026-01-31

Recent paper on Climate Change in this journal considered Green Steel and argued for a DRI-EAF route using charcoal from tree branches in forest plantations that are maintained by workers using hand tools. And this will continue even more in proposing charcoal’s major use in blast furnaces. There are many operating iron blast furnaces in Indonesia and worldwide using coke and as the process is capital intensive they must be operated for a long time. This means that most blast furnaces with their coke ovens will continue producing iron and large amounts of CO₂ for many years yet, making zero carbon unattainable. An obvious question is: Can coke in the iron blast furnace be substituted by the more climate friendly charcoal? And if yes, will it be economic and will the blast furnace be as productive as now? Following an exhaustive literature study this paper answers the question positively. It is demonstrated that there are two fundamentally different requirements of carbon in blast furnaces that people have not appreciated and instead followed a hundred year tradition in treating them as one. This paper exposes them as two different carbons, namely: the cohesive zone carbon and the shaft zone carbon. This is perhaps the first time that this has been done, as so far these two quite different evidence-based theory requirements of a blast furnace carbon have been invariably introduced as a single carbon, namely: coke in coke BFs and charcoal in charcoal BFs. It is also demonstrated that large blast furnaces can operate with this dual carbon burden not too differently from a 100% coke or a 100% charcoal carbon burdens. It is also good economics as cheaper charcoal is substituted for expensive coke.

Pipe Stress Analysis of the Steam Pipe of Project Tidore Power Plant (2 X 4 MW) Using CAESAR II

Franky Pasaribu — 2026-01-31

Pipe stress analysis is an important step to ensure that the piping system can function properly and safely. The main goal is to ensure that the piping design can withstand the pressure and load without failure. This analysis follows the guidelines of ASME B31.1 Power Piping, which regulates the design and construction of piping in a Power Plant. The analysis was performed using software Caesar II. This software helps clip various working conditions and measure the pressure in the piping system. From the analysis report, no overstress problems were found in the steam piping line. Since the system already meets ASME B31.1 standards, no changes were needed to the number, position, or type of pipe supports.

Economy Class Passenger Seat Design Concept for Flights in Indonesia

Erwin Nurrizki Tanjung — 2026-01-31

Aircraft seat bench concept is designed with three adjustment points—armrests, backrest, and the middle of the backrest—and is equipped with a headrest to support the passenger’s head and neck comfort. These features aim to enhance passenger comfort without limiting the movement space of neighboring passengers, which is often a concern in conventional aircraft seat designs.

To reduce production costs and maintain efficiency, the materials used are commonly available in the market. The seat frame is made of lightweight yet strong aluminum, the seat cushion and backrest utilize polyurethane (PU) foam for comfort, and the outer covering uses synthetic leather, which is affordable yet visually appealing. This material selection facilitates mass production and simplifies maintenance.

Structural testing using Autodesk Inventor software indicates that the design is safe for use, achieving a safety factor of 3.62, which signifies strong resistance to stress and load during usage.

Optimization of Bipolar Plate Machining Process Using the Taguchi Method on CNC 3-Axis

Radhi Maladzi — 2026-01-31

This study aims to optimize the machining parameters of bipolar plates using a CNC 3-axis milling machine based on the Taguchi method. Bipolar plates play a crucial role in proton exchange membrane fuel cells (PEMFCs), where dimensional accuracy and surface quality directly affect cell performance. The machining parameters considered in this research include spindle speed, feed rate, and depth of cut. An L9 orthogonal array was selected to design the experiments, and surface roughness as well as material removal rate (MRR) were evaluated as performance characteristics. Signal-to-noise (S/N) ratio analysis was applied to determine the optimal parameter combination. The results show that spindle speed and feed rate have the most significant influence on surface roughness, while depth of cut mainly affects the MRR. The optimal setting obtained was 3500 rpm spindle speed, 300 mm/min feed rate, and 0.2 mm depth of cut, which produced the lowest surface roughness and acceptable MRR. The confirmation experiment validated the Taguchi model prediction with an error of less than 5%. These findings demonstrate that the Taguchi method is an effective tool for optimizing CNC machining parameters of bipolar plates, improving both quality and manufacturing efficiency.

Technical and Economic Study of Fast Charging Systems Electric Heavy Equipment in Industrial and Port Areas

Rahmat Noval — 2026-01-31

The electrification of heavy equipment presents both an opportunity and a challenge for Indonesia’s industrial and port operations. Despite advancements in battery energy density and power electronics, the lack of efficient fast-charging infrastructure remains a critical bottleneck. This study evaluates the technical and economic feasibility of implementing high-power DC fast-charging systems for electric heavy machinery in port and industrial settings. Using HOMER Grid and MATLAB-based simulations, three charging configurations (90 kW AC, 250 kW DC, and 500 kW dual-gun DC) were analyzed. Results indicate that the 500 kW system reduces downtime by up to 70%, increasing equipment availability from 75% to 96%. Economic analysis shows a payback period of 4.8 years, internal rate of return (IRR) of 18.7%, and levelized cost of electricity (LCOE) of IDR 2,100/kWh. The findings support the deployment of modular fast-charging hubs to accelerate electrification in logistics and port sectors

Front Cover Vol 04 No 01 2026

2026-01-31

Table of Content Vol 04 No 01 2026

2026-02-15