Recent in Engineering Science and Technology

A Risk-Based Integrity Management of CO₂ Pipelines in CCUS: Integration of Failure Mechanisms, Risk Assessment, and Inspection Strategies—A Review

Risdianto — 2026-10-11

The accelerated deployment of Carbon Capture, Utilization, and Storage (CCUS) systems requires safe and reliable CO₂ transportation infrastructure. Pipelines remain the most feasible option for large-scale CO₂ transport; however, dense-phase thermodynamics, impurity interactions, decompression behavior, and environmentally assisted degradation create integrity challenges that differ from those of conventional hydrocarbon pipelines. This review examines how failure mechanisms, risk assessment methods, and inspection strategies can be integrated into a Risk-Based Inspection (RBI) framework for CO₂ pipelines. Literature was synthesized from studies indexed in Scopus and Web of Science, with emphasis on corrosion, fracture propagation, probabilistic risk assessment, monitoring technologies, and inspection planning. The reviewed evidence indicates that corrosion-related degradation and running fracture are the most critical threats, while probabilistic and reliability-based approaches are increasingly used to address uncertainty. Nevertheless, integration between degradation assessment, risk modeling, and inspection optimization remains fragmented. This paper proposes a dynamic RBI concept that links CO₂-specific degradation mechanisms, Bayesian risk updating, real-time monitoring, and adaptive inspection scheduling. The proposed synthesis supports more reliable, risk-informed integrity management for future CCUS pipeline networks.

Preliminary LEAP-Based Scenario Analysis of Electricity Demand and Renewable Energy Development in South Sulawesi

La Ode Masri Ande Kolewora — 2026-10-27

South Sulawesi possesses abundant renewable energy potential, particularly from hydro, wind, solar, and biomass resources. However, rapid population growth and increasing energy consumption across sectors create challenges in ensuring sustainable energy supply and planning. This study aims to project the mid-term renewable energy supply and demand in South Sulawesi using the Long-range Energy Alternatives Planning (LEAP) model. By simulating various scenarios—including the business-as-usual (BAU) and renewable policy intervention scenarios—this research analyzes the region’s future energy trajectory up to 2035. The findings reveal that South Sulawesi’s average population growth of 1.028% (approximately 142,000 people per year) and electricity demand growth of 7.94% annually significantly increase regional energy needs. Without intervention, fossil fuels will continue to dominate the energy mix, but policy-driven scenarios demonstrate that renewable energy contributions could exceed 45% of the total supply. The study provides valuable insights for regional energy planning and supports policy formulation toward achieving a sustainable, low-carbon energy system in South Sulawesi.

Auditing Physical Consistency in Engine Fault Detection Using Domain-Informed Monotonic XGBoost and Explainable Boosting Machine

Abdul Azis Abdillah — 2026-10-31

Machine-learning models for engine fault detection are usually judged by predictive accuracy, although a model can score well while learning relationships that contradict engine physics. This study proposes a physical-consistency audit that combines domain-informed monotonic constraints in XGBoost with the glass-box Explainable Boosting Machine (EBM). Using a public dataset of 19,533 engine records with six sensor variables, seven classifiers were benchmarked under a leakage-safe protocol with a stratified hold-out test set, inner-cross-validated tuning, repeated cross-validation and out-of-fold threshold selection. Three XGBoost configurations with identical hyper-parameters (unconstrained, domain-constrained and reverse-constrained) were then compared. The boosting models performed statistically alike, with EBM the best (test ROC-AUC 0.701). Imposing engineering-consistent constraints significantly reduced ROC-AUC (−0.016 on the test set; 95% CI −0.023 to −0.009) and removed almost all attribution to oil pressure and oil temperature, whereas reversed constraints had no cost. SHAP and EBM shape functions independently showed all three constrained sensors acting opposite to expectation, and semi-synthetic experiments with known physics reproduced this signature only when labels were inverted. The audit therefore exposes physically implausible learning and flags possible label inversion without expert relabelling.

Analysis of the Effect of Air Inlet Filter Replacement on Gas Turbine Performance at Unit 1A of Bekasi Power Combined Cycle Power Plant

Gilang Fitra Ardiansyah — 2026-10-31

The air inlet filter is a critical component in a gas turbine system because it ensures that clean air enters the compressor and combustion chamber. The accumulation of dust, moisture, and airborne contaminants can increase pressure drop across the filter, reducing airflow rate and adversely affecting compressor performance, combustion efficiency, and overall gas turbine operation. This study aims to analyze the effect of air inlet filter replacement on the performance of Gas Turbine GT1A at Bekasi Power Combined Cycle Power Plant (CCPP). A quantitative comparative approach was employed by comparing operational data before and after air inlet filter replacement. Secondary data were obtained from the Distributed Control System (DCS), including compressor inlet temperature, compressor outlet
temperature, compressor inlet pressure, compressor outlet pressure, combustion chamber temperature, turbine exhaust temperature, fuel gas flow rate, and generator load. The performance analysis was conducted using Brayton cycle thermodynamic equations to evaluate compressor efficiency, combustion chamber efficiency, turbine efficiency, and thermal efficiency. Furthermore, a Fishbone Diagram (6M) analysis was utilized to identify the root causes leading to air inlet filter replacement. The results indicate that replacing the air inlet filter improves the quality and quantity of intake air supplied to the compressor, leading to enhanced combustion conditions and
improved gas turbine performance. The study highlights the importance of periodic air inlet filter maintenance in maintaining operational reliability, efficiency, and long-term performance of gas turbine systems