Ministry of Energy

High-fidelity numerical simulations of CO2 geological storage are computationally expensive, impeding the rapid assessment of leakage risks associated with mobile free gas. To address this, this study proposes a comprehensive data-driven framework ranging from mechanism analysis to parameter optimization. Leveraging a data set of 4,631 time-series samples derived from representative global sequestration projects, we constructed a generalized predictive model incorporating nine key geological and operational parameters. Among the tested algorithms, XGBoost demonstrated superior performance in capturing the temporal evolution of residual (RTI) and solubility trapping indices (STI). Crucially, the physics-based SHAP analysis quantified the geological controls: RTI is primarily driven by residual gas saturation via capillary hysteresis, while STI is strictly governed by formation water salinity, consistent with the thermodynamic limits of Henry’s Law. Furthermore, coupling the surrogate model with the NSGA-II algorithm generated Pareto-optimal solutions that effectively balance short-term safety and long-term stability. The optimization results establish strict quantitative screening criteria: formations with high permeability (>400 mD), ultralow salinity (<5 kppm), and moderate residual gas saturation (<0.22) are identified as optimal for safely restricting the initial mobile gas index to below 30% within the first 50 years. Large-scale Monte Carlo simulations (100,000 evaluations) confirm the robustness of these criteria. This framework bridges data-driven insights with physical mechanisms, providing a cost-effective tool for prefeasibility analysis and optimized scenario generation in CCUS projects.

s of mazut gives rise to an enormous primary plume, its 512-fold dilution along a 90 km radius appreciably alleviates the immediate direct toxicological impact [9].Together with the 30% penetration factor, however, the residual PM 2.5 concentration may still contribute a readily measurable #/m3 value to the city's general background air quality and be in excess of WHO daily guidelines during conditions of low wind dispersion [10].The outcome verifies that the distance of 80-90 km is insufficient to provide 'complete immunity' against the emissions of industries, thereby prompting the use of 'clean coal' technology/WESP in the power stations [11].In conclusion, it can be asserted that the simplified exponential wind model is an essential 'tool' in the hands of regional planners to estimate the 'risks to the environment' in the absence of complex 'dispersement software tools' in the initial stage [12].Lastly, the outcome strongly supports the formulation of a tough 'legislative policy regarding the use of mazut in thermal power stations to protect the health of distant urban areas ' [13].

Abstract Permanent magnet synchronous motor (PMSM) control techniques have gained attention as the performance requirements of motors increase. Traditional control strategies are limited in coping with variations and disturbances. In this study, a new PMSM controller based on parameter self-tuning is proposed, which enhances the system’s interference resistance and control accuracy through real-time monitoring and dynamic adjustment of parameters. Experiments show that the new controller reduces the speed overshoot by 20% and the tuning time by 15% under sudden load changes. When the motor parameters change by 10%, the speed error is still controlled within 1%, which shows strong robustness. In the physical experiment, under high-speed operating conditions (3000 rpm), the torque fluctuation is reduced by 25%, and the current harmonic content is reduced by 15%, significantly improving the motor’s running smoothness and energy efficiency ratio. This research provides a new technical way for high-performance control of permanent magnet synchronous motors and has a wide application prospect.

This study examines the effectiveness and economic feasibility of purchasing and leasing a fleet of tankers for fuel distribution to gas stations. The fleet used consists of 10 units with various capacities. The results show that the initial investment for purchasing reached Rp19,377,842,022.10, while the rental cost was only Rp17,925,390,000. The annual operating cost for purchasing was recorded at Rp53,193,591,706.93, higher than the rental cost of Rp51,585,649,513.20. Despite the higher operating costs, the annual depreciation for purchasing was recorded at Rp1,695,561,201.60 with a BEP value of Rp150,600,071,968.05. From a financial perspective, the IRR for leasing reached 18%, slightly lower than the purchase which reached 19%. However, the PV value of income from leasing is greater, namely Rp199,184,815,732.30, compared to purchasing which is only Rp199,509,891,668.76. Based on the analysis of the profitability index and the investment payback period, the leasing scheme is proven to be more effective and feasible than purchasing, both in terms of initial costs, operational costs, and long-term profit potential, and is more feasible to implement.

ABSTRACT In this paper, a large‐diameter diffuse argon plume is generated through being excited by a negatively‐biased sinusoidal voltage. The diffuse plume increases in length with increasing peak voltage and argon flow rate, which transitions to a nonuniform plume when voltage amplitude exceeds a threshold. The diffuse plume initiates at the rising voltage edge, while the nonuniform plume initiates at the rising and falling edges. From fast photography, the diffuse plume originating from the discharges at the rising voltage edge is speculated to operate in a Townsend discharge regime, while the discharge at the falling voltage edge is filamentary in the nonuniform plume. By optical emission spectroscopy, plasma parameters including electron temperature, electron density, and atomic oxygen concentration have been investigated.

This study investigates the corrosion resistance of copper-coated reinforcing steel bars embedded in concrete and exposed to a simulated marine environment for (28, 56, and 90 days) at temperatures of (298, 308, and 318 Kelvin). A novel thermal spray technique was integrated into the hot rolling process to deposit copper powder onto heated steel bars. The coated bars were characterized using X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive spectroscopy (SEM/EDS), and atomic force microscopy (AFM), revealing a dense, uniform microstructure with reduced surface roughness (63.99 nm) and increased particle density (〖30.2 ×10〗^6 particles/mm²) compared to the uncoated steel bar. Electrochemical measurements demonstrated a substantial decrease in corrosion current density (I_corr) for the coated specimens (〖1.11×10〗^(-7) A/cm² at 298 Kelvin), along with the highest protection efficiency (92.29 %). Electrochemical impedance spectroscopy (EIS) further confirmed the enhanced performance of the coated bars, with a superior total impedance resistance of 30,192 Ω.cm² and Warburg resistance of 18,320 Ω.cm^2, compared to uncoated ones (17,561 Ω.cm² and 9,363 Ω.cm^2), respectively. These results highlight the potential of copper coatings as a viable solution for extending the service life of reinforced concrete structures in aggressive environments.