Advanced Engineering Forum Vol. 57

Abstract: It has been demonstrated that thin films of fluorine-doped Bi₂O₃ can be prepared using sol-gel spin coating. An X-ray diffraction (XRD) and energy dispersive analysis were used to examine samples. Using a sol-gel spin-coating technique, different electrolytes and sweep rates were used in the study to characterize fluorine-doped Bi₂O₃ films. In the results of the studies, it was extensively examined whether these films could be used in the fabrication of electrochromic devices. The enhanced properties of fluorine doped samples are due to their increased separation efficiency and strong oxidation potential. For two hours, the samples were exposed to temperatures ranging from 350 °C to 450 °C. F:Bi₂O₃ films have been the subject of an intercalation and deintercalation investigation. Therefore, H₂SO₄ and KCl are used to intercalate H+ and K+ ions in PC electrolytes. Sharp transmittance peaks at the band's edge in a spectrum with good crystallinity signify interfering patterns. Band assignment 3482 cm^-1, stretching vibration of carbohydrate, C-OH, 2432 cm^-1 asymmetric stretching vibration, 1625 cm^-1 unconjugated C=O stretching vibration, and 1383 cm^-1 bending vibration of C-H are among the numerous assignments in Fourier transform infrared spectroscopy. Additionally, 1101 cm^-1 are vibrations of hydroxyl groups and 625 cm^-1 are metallic bond vibrations of F:Bi₂O₃. The surface roughness of F:Bi₂O₃ films was found to have significantly improved. It is probable that a sol-gel spin coating process at 200 °C produced dense, irregularly shaped Bi₂O₃ grains. The thermodynamic characteristics of the corrosion process for Bi in concentrated sulfuric acid solution were studied. These parameters were Ea (activation energy), H (enthalpy change), and S (entropy change).

Abstract: The deformation of semisolid slurry within a mould or die is complex in the case of semisolid forming. Understanding and improving the efficiency of such a forming process requires a systematic study of the flow of semisolid slurry under deformation. This study considers the flow characteristics of semisolid A356 alloy slurry under deformation between two parallel plates. The semisolid slurry is represented here by an apparent viscosity under deformation and cooling. The process is then modelled using momentum and energy conservation equations, comprising an analytical solution to predict related flow and deformation behaviour of the slurry. The final solution involves coupling the governing equations by developing a numerical code on the FORTRAN platform. The model then predicts the distribution of temperature, solid fraction, apparent viscosity of the semisolid slurry, and stress to deform the slurry. The deformation stress found in this study has a realistic value, which is also supported by the available research. Prediction of deformation characteristics for any semisolid slurry is possible using the present model, which is simple and appropriate. This study also found that the deformation stress increases with an increase in the plate length and decreases with an increase in the slurry deformation velocity.

Abstract: Low Pressure (LP) flash column is one of the equipment at CO₂ removal plant, operated since 2003 with a design pressure and temperature of 1.75 kg/cm²g and 90 °C, respectively. The LP flash column functions as a place for the CO₂ gas to be absorbed by aMDEA and produces lean amine. At turn around in 2021, a crack with a length approximately 5 cm was found on the inside of the top part of the LP flash column (shell area near weld). Repairment was carried out by providing a crack stopper on the crack tip, gouging, non-destructive evaluation (NDE) and welding. However, when NDE was applied, new cracks appeared around the initial crack. Some inspection and testing were further carried out to find the root cause and appropriate repair method. The results indicate that the crack has a branching pattern and its propagation cuts through trans-granular grain. Upon further analysis, there was unusually higher chloride content on the crack surface area and hardness value was higher (202-209 HB) than standard hardness value for ASTM A240-304L (≤ 201 HB) which indicates the crack was caused by chloride stress corrosion cracking (Cl-SCC). Excessive load or stress caused cracks to propagate rapidly and uncontrolled. Based on ASME PCC-2, the Butt Weld Insert Plate was selected as the repair method due to its suitability for a wide range of defects, its ability to reduce crack propagation and its provision of a permanent repair solution. Another NDE was conducted after the repair to ensure that the repairs were properly executed, with no welding defects or new cracks in the repair area. The results confirmed that there were no defects in the shell material following the installation of the butt weld insert plate.

Abstract: This study explores the effects of magnetic fields on the electrokinetic behavior of reservoir fluids and their discharge characteristics under varying pressure conditions. A specialized experimental setup was designed to replicate reservoir environments, incorporating a high-pressure column, PVT bomb, electromagnet and various measurement and control instruments. Experiments were conducted to assess how different magnetic field strengths (ranging from 40 to 150 mT) influence voltage, resistance and water discharge across a pressure range of 1.6–14.4 atm. The findings indicate that magnetic fields enhance fluid behavior by improving ion mobility and electrical conductivity, which results in greater water discharge and more stable fluid flow at elevated pressures. This research offers important insights into how magnetic fields can improve fluid transport in porous media, with promising implications for advancing enhanced oil recovery (EOR) methods.

Abstract: Data collection in the lateral and vertical axes is crucial to inspect the heterogeneity of the inflow condition of the wind tunnel and the development of the boundary layer. A customized traverse system uses three stepper motors to control the X, Y, and Z positions with the structure is built with 2020 and 2040 aluminum extrusion for easy assembly. To ensure positional accuracy, the traverse system is tested on its accuracy with the mean absolute error (MAE) for single movements must be less than 1.5mm for the Y and Z axes to accurately capture the lateral-vertical flow structure of the wind tunnel's inflow condition. The MAE for single movements is 1.189mm for the X-axis, 0.069mm for the Y-axis, and 0.054mm for the Z-axis, all within the set limits. Only the X-axis 10mm increment movements failed at all tested speeds due to the errors in the smaller movements cumulated into a more significant error. In contrast, the mean MPE for other increments is 0.93%. The Y and Z axes have continuity MPEs of 0.13% and 0.47%, respectively, within the requirements.

Abstract: Gauge repeatability and reproducibility are becoming a versatile tool for determining the effectiveness or adequacy of manual and automatic measuring systems. The knowledge of variation is essential as variation is inherent in every measurement process and is sometimes unpredictable. Understanding and controlling variation in measurement systems is critical to reducing variability. This paper presents a design of an experiment to analyze gauge capability and uses the same designed experiment to test and compare the variation for two automatic measurement systems. Three factors were determined as a starting point and were compared at two levels. The test results were analyzed using the expanded ANOVA method in Minitab. Significant conclusions were drawn out and a recommendation for further work is suggested.

Abstract: Recently, wind energy has become increasingly popular as a sustainable energy source. Variable speed wind energy conversion systems (VS-WECSs), particularly those using Permanent Magnet Synchronous Generators (PMSGs), are more prevalent to other generator systems due to their higher capacity for electricity generation and adaptability to fluctuating wind conditions. This research presents a new control algorithm that is based on Higher Order Sliding Mode Control (HOSMC) to enhance maximum power tracking (MPT) for PMSG-based wind turbines (WT) under variable wind conditions and system uncertainties. The research employs second order super-twisting sliding mode control (SO-STSMC) to the back-to-back converter that connected the PMSG to the grid. In the proposed controller, the machine side converter uses optimal power control to regulate the DC-link voltage, and the grid side converter provides maximum power tracking (MPT) for the turbine. The proposed HOSM controller mitigates chattering effect associated with conventional sliding mode control, thus improving system robustness, stability, and power efficiency. Simulation of the HOSMC-based system was performed using MATLAB/SIMULINK. To demonstrate the effectiveness of the Maximum Power Tracking (MPT) of the proposed controller, the output power is compared with Proportional-Integral (PI) and First-Order Sliding Mode (FOSM) controllers while varying wind speed over time. Simulation results show that the designed Higher-Order Sliding Mode (HOSM) controller significantly reduces chattering and effectively maximizes the output power by 89% over a wide range of wind speeds compared to other controllers.

Abstract: This article explores the application of digital twin technology to enhance the operation of wafer sawing machines in materials handling and semiconductor manufacturing. An empirical study was conducted on the packaging production line at Minghsin University of Science and Technology, aimed at addressing talent training challenges and the imbalance between supply and demand in the industry. The research focuses on designing and developing an integrated system that combines digital twin and mixed reality technologies. The development process involved multiple stages, including on-site visits, machine operation instruction, certification content creation, expert validation, small-scale testing, and iterative improvements. The study evaluates the effectiveness of the system by comparing pre- and post-experiment scores provided by industry experts, analyzing operation times of five participants, and gathering qualitative feedback. Results indicate that simulation training using digital twin and mixed reality significantly enhances participants' scores and operational proficiency. This research presents a digital twin-based training and certification model that effectively improves students' success rates in certification exams.