Search Results (4)

In this article, the authors have experimentally investigated the changes in four key properties of six non-edible low-impact energy carries based on rapeseed oil quality grade HM and viscosity grade VG46, which were used as a filling in the hydraulic system of a round wood sorting and transporting trolley. These oils were enriched with thermo-oxidizing, extreme-pressure additives, anti-foaming, and lubricating additives to enhance performance. Three supervised machine learning prediction algorithms were used to predict key parameters essential for optimizing their performance and RUL (remaining useful life), namely support vector regression (SVR), generalized additive model (GAM), and Gaussian process regression (GPR). The model’s performance was scored from multiple perspectives using metrics such as root mean square error (RMSE), mean absolute error (MAE), mean absolute percentage error (MAPE), and coefficient of determination (R²) to state actual values, thereby demonstrating the validity of the models in predicting lubricant lifespan. Based on the collected data, this study demonstrated that it is possible to predict the degradation of hydraulic oil factors to the limit state, integrate these parameters into a comprehensive metric for more accurate remaining useful life (RUL) estimation, and obtain actual operating trends. A negative correlation was found between the remaining useful life (RUL) and parameters such as acid number, kinematic viscosity, peroxide number, and water content. The comparison of modeling algorithms showed that all three algorithms adequately described the degradation patterns. By using these performance criteria, we defined the most accurate and reliable soft-computing model for predicting hydraulic fluid parameters, providing valuable insights into optimizing machine learning models for practical applications. Full article

The Bacillus megaterium LVN01 species native to Colombia has demonstrated the ability to metabolize different coproducts or industrial waste (such as fique juice, cane molasses, and residual glycerol) and accumulate polyhydroxybutyrate (PHB), giving it potential in the bioplastics industry. In this research, the potential of liquid digestate as a carbon source for the production of PHA polymers in fermentation processes with this bacterial strain was evaluated. Favorably, it was found that B. megaterium utilizes the nutrients from this residual substrate to multiply appropriately and efficiently synthesize poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). Bench-scale aerobic batch fermentation, under the operational conditions of this research [volume: 3 L; temperature: 30.8 °C; agitation: 400 rpm; pH: 7.0 ± 0.2; dissolved oxygen: 100% saturation; antifoam: 10% (v/v)], generated maximum values of dry cell weight (DCW) (0.56 g cell L⁻¹) at 60 h, while the maximum PHBV yield (360 mg PHBV L⁻¹) occurred at 16 h, which is very favorable for sustainable degradable bioplastics production. Additionally, GC–MS and NMR analyses confirmed that the PHBV copolymer synthesized by B. megaterium is made up of the monomers 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV). Furthermore, the thermal properties determined by TGA (Tonset = 283.1 °C; Tendset = 296.98 °C; Td = 290.114 °C) and DSC (Tm = °C 155.7 °C; ΔHf = 19.80 J g⁻¹; Xcr = 18.17%) indicate that it is a thermally stable biopolymer with low percentages of crystallinity, providing flexibility that facilitates molding, adaptation, and application in various industrial sectors. Full article

Absorption is one of the most established techniques to capture CO₂ from natural gas and post-combustion processes. Nevertheless, the absorption process frequently suffers from various operational issues, including foaming. The main objective of the current work is to elucidate the effect of degradation product on the foaming behavior in methyldiethanolamine (MDEA) and piperazine (PZ) solution and evaluate the antifoaming performance of polydimethylsiloxane (PDMS) antifoam. The foaming behavior was investigated based on types of degradation product, temperature, and gas flow rate. The presence of glycine, heptanoic acid, hexadecane, and bicine in MDEA-PZ solution cause significant foaming. The presence of hexadecane produced the highest amount of foam, followed by heptanoic acid, glycine and lastly bicine. It was found that increasing the gas flow rate increases foaming tendency and foam stability. Furthermore, increasing temperature increases foaming tendency, but reduces foam stability. Moreover, PDMS antifoam was able to reduce foam formation in the presence of different degradation products and at various temperatures and gas flow rates. It was found that PDMS antifoam works best in the presence of hexadecane with the highest average foam height reduction of 19%. Hence, this work will demonstrate the cause of foaming and the importance of antifoam in reducing its effect. Full article

Lubricant foaming and its mitigation is an active area of research driven by demands from modern machinery that require foam-free lubricant operation over extended periods and under adverse conditions. Tackling lubricant foaming has proven to be challenging due to interdependent foam stabilization mechanisms and a multitude of antifoam inactivation routes. This perspective briefly outlines the key challenges faced by researchers in this field. Overcoming these challenges to create lubricants with superior foaming characteristics requires the development of new lubricant and antifoam chemistry as well as a shift from the existing trial-and-error methods to mechanistic-insight-driven lubricant formulation and antifoam design. Full article