Search

• A three-phase CO 2 /lubricant swirl ejector with swirl motive nozzle. • Heterogeneous mixture model developed for ejector with swirl motive nozzle. • Helical pitch and oil circulation ratio affect ejector performances. • Empirical correlation of entrainment ratio with swirl number. At present, most simulations of ejectors ignore the presence of lubricating oil, which may affect the accuracy of the results. Additionally, there has been less research conducted on the influence of motive nozzles with swirl generators on the performance of ejectors. In this study, a heterogeneous mixture model was developed for a three-phase swirl ejector equipped with a motive nozzle featuring a swirl generator. This article examines the performance of swirl ejectors under supercritical conditions using three-dimensional numerical simulations conducted in ANSYS. The study explores swirl ejectors with varying helical angles of 77°, 64°, 58°, 50°, 37°. The study also takes into account the influence of lubricating oil to enhance the practicality of the research. Firstly, lubricating oil with a volume fraction of 2 % was introduced into both the motive and suction streams, followed by conducting an ejection analysis. The results indicate that the swirl enhances the entrainment ratio, and the swirl strength can be modified by changing the helical angle. A smaller helical angle results in greater swirl strength and a higher entrainment ratio. When the helical angle is 37° and the helical pitch is 20 mm, a swirl number of 0.42, an entrainment ratio of 0.998, and an effective entrainment ratio of 0.863 is achieved. However, when the oil circulation ratio in the suction stream is increased from 2 % to 10 % while keeping the oil circulation ratio of the motive stream constant, the entrainment ratio decreases. [ABSTRACT FROM AUTHOR]

This study shows how the presence of metal-impregnated biochar influences the kinetics of the catalytic conversion of waste motor oil (WMO) into a diesel-like fuel (DLF). First, the initial metal concentration in the wet impregnation process was optimized, showing that high metal concentrations tend to clog the biochar pores, reducing the reaction's conversion and speed. Zinc and calcium showed higher kinetic constants at the optimized conditions than nickel, while the yield- and selectivity-to-liquid products were unaffected. Then, a reduction method was developed for impregnating metal particles of calcium oxide to enhance the metal dispersion at the biochar surface. This material showed the best performance in the reaction due to the presence of small particles instead of metal agglomerates. An increase of about 280% in the kinetic constant at 420 °C and a much lower activation energy (246 kJ mol−1) compared to the thermal cracking (308 kJ mol−1) was obtained. Finally, the DLF from the best catalytic system was analyzed. Interestingly, the fuel showed similar rheological properties to commercial diesel with a similar hydrocarbon distribution but with the presence of smaller hydrocarbon chains. [ABSTRACT FROM AUTHOR]

Switchable solvents (SS) are a class of liquids with the unique ability to significantly alter their physical properties in response to external stimuli such as changes in temperature or the introduction or removal of CO2 gas. This reversible behaviour allows them to return to their original state with minimal changes, making them highly advantageous for various applications. A notable example of a switchable solvent is waste carbon dioxide gas, which is non‐toxic, non‐flammable, and cost‐effective. The versatility of switchable solvents extends to their polarity and physical states, which can be modified through molecular adjustments, opening new pathways for research and industrial applications. This review provides a comprehensive overview of switchable solvents, including their classification, history, properties, and applications, with a particular focus on their role in green chemistry. The types of switchable solvents discussed include Switchable‐Polarity Solvents (SPS), Switchable‐Hydrophilicity Solvents (SHS), and Switchable Water. Each type is examined in terms of synthesis, chemical properties, and development. The desirable properties of switchable solvents, such as their efficiency and recyclability, make them suitable alternatives to traditional solvents in various fields. Their applications range from water treatment and oil extraction to cleaning solid particles and recovering residual motor oil. Additionally, switchable solvents have proven effective as reaction media and in recovering polystyrene from foam. This paper also highlights the environmental benefits of switchable solvents, emphasizing their role in reducing the ecological impact of chemical processes. The potential for future developments in this field is significant, with ongoing research aimed at enhancing their performance and expanding their applications. By providing a detailed analysis of switchable solvents, this review aims to support researchers and industry professionals in developing more sustainable and efficient chemical processes. [ABSTRACT FROM AUTHOR]

ABSTRACT Here, we demonstrate mid‐field 1H NMR spectroscopy combined with chemometrics to be powerful in the classification and authentication of motor oils (MOs). The 1H NMR data were processed with a new algorithm for simultaneous phase and baseline correction, which, for crowded spectra such as those of the refinery products, allowed for more accurate estimation of phase parameters than other literature approaches tested. A principal component analysis (PCA) model based on the unbinned CH3 fingerprint region (0.6–1.0 ppm) enabled the differentiation of hydrocracked and poly‐α‐olefin‐based MOs and was effective in resolving mixtures of these base stocks with conventional base oils. PCA analysis of the 1.0‐ to 1.14‐ppm region enabled the detection of poly (isobutylene) additive and was useful for differentiating between single‐grade and multigrade MOs. Non‐equidistantly binned 1H NMR data were used to detect the addition of esters and to establish discriminant models for classifying MOs by viscosity grade and by major categories of synthetic, semisynthetic, and mineral oils. The performances of four classifiers (linear discriminant analysis [LDA], quadratic discriminant analysis [QDA], naïve Bayes classifier [NBC], and support vector machine [SVM]) with and without PCA dimensionality reduction were compared. In both tasks, SVM showed the best efficiency, with average error rates of ~2.3% and 8.15% for predicting major MO categories and viscosity grades, respectively. The potential to merge spectra collected from different NMR instruments is discussed for models based on spectral binning. It is also shown that small errors in phase parameters are not detrimental to binning‐based PCA models. [ABSTRACT FROM AUTHOR]

The basic tribological experiments have reported that nano-graphene lubricating oil has excellent anti-friction and anti-wear properties, which has been widely concerned. However, the real anti-friction effect of nano-graphene lubricating oil and its impact on engine power performance, economic performance and emission performance remain to be proved. This has seriously hindered the popularization and application of nano-graphene lubricating oil in the engine field. In this paper, nano-graphene powder was chemically grafted to prepare nano-graphene lubricating oil with high dispersion stability. The influence of nano-graphene on physicochemical properties of lubricating oil was studied, and the influence of nano-graphene on engine power performance, economic performance and emission performance was explored. The results show that after modification, the dispersion of nano-graphene in lubricating oil is improved. Compared with pure lubricating oil, the addition of nano-graphene makes the kinematic viscosity of lubricating oil slightly lower, and has little effect on the density, flash point, pour point and total acid value of lubricating oil. The reversed towing torque of nano-graphene lubricating oil is reduced by 1.82–5.53%, indicating that the friction loss decreases. The specific fuel consumption of the engine is reduced, which indicates that the fuel economic performance is improved. Engine HC+NOX, CH4, CO2 emissions do not change much, but particulate matter (PM) emissions increase by 8.85%. The quantity concentration of nuclear particles, accumulated particles and total particles of nano-graphene lubricating oil are significantly higher than that of pure lubricating oil. And the increase of the quantity concentration of accumulated particles is more obvious than that of nuclear particles, and the larger the load, the more obvious this phenomenon. In order to apply nano-graphene lubricating oil to the engine, it is also necessary to further study its impact on the post-processing system, adjust the control strategy of the post-processing system and then test and calibrate. [ABSTRACT FROM AUTHOR]

ABSTRACT The anti‐emulsification property of lubricating oil is an important index to measure the quality of oil. In this paper, the behaviour of surfactants such as lubricating oil additives at the oil–water interface and the influence of the position of ethylene oxide (EO) and propylene oxide (PO) in the block polyether demulsifier on the demulsification effect were investigated by molecular simulation and experimental verification. The properties of seven lubricating oil additives with different functions and two pairs of isomers were investigated by molecular simulation, and their demulsification effects were verified by experiments. Some simulation results such as interface thickness and density distribution can accurately predict the experimental demulsification effect. Moreover, it was found that the position isomerism of surfactants affected the demulsification performance by changing the lipophilic balance and interface properties. The demulsification performance of sequenced copolymers is generally better than that of anti‐sequenced copolymers. The accurate prediction of molecular dynamics simulation makes the selection of lubricating oil demulsifier more extensive and has practical application value. [ABSTRACT FROM AUTHOR]

This work focuses on the evolution of lubrication wedge shaping in internal combustion piston engines, taking into account liquid microflows on curved surfaces and coating microgeometries. It introduces a new approach to the analysis of friction losses by simulating the microflow of lubricating oil between the surfaces of piston rings cooperating with the cylinder surface. The models used take into account three types of microgeometry and material expansion. Key results indicate that microirregularities with a stereometry of 0.1–0.2 µm significantly influence the distribution of oil film thickness in the phase of maximum working pressure, which is critical for the functioning of the seal ring. The innovation of the work consists of demonstrating that, despite small changes in the friction force and power in the piston rings, changes in the minimum values of the oil film thickness are significant. The work highlights the failure to take into account microgeometry parameters in friction models, which leads to significant errors in the simulation results, especially in terms of oil film continuity and the contribution of mixed friction. The simulations also indicate that advanced geometric models with high mesh resolution are necessary only for the assessment of changes in oil film thickness during the highest pressure increase in the combustion chamber and taking into account various mixed friction conditions. The results suggest significant progress in engine design and performance, confirming the importance of advanced fluid and mixed friction models in piston engine lubrication research. [ABSTRACT FROM AUTHOR]

Cupro–nickel alloy of 70/30 grade was experimented for its formability by SPIF tests, namely straight groove test and wall angle test using a ball attached tool, to emphasize the concern on formability and surface roughness. Two different types of ball were used, one ball was used in polished form and another one was surface-textured using Nd-Yag laser. The cupro–nickel alloy has excellent corrosion resistance and popularly used in marine environments. In this research, an attempt has been made to study the formability when using Chrome steel laser ablated ball. The results concluded that Chrome steel laser ablated ball with oil as lubrication has avoided the occurrence galling and at the same time improved the formability. When experimenting with chrome steel polished ball, the tool and sheet contact is high and the lubricating oil will be less and it is causing the sheet to get heated. The dimples on the ball's surface made by the laser retain more lubricating oil and thereby decreasing the friction which eventually leads to the delayed fracture. It is found that the formability was increased by 16% in straight groove test, 4.8% for wall angle test and surface roughness values were decreased by 1.4%. [ABSTRACT FROM AUTHOR]

This study focuses on the development of adsorptive materials to retain degraded 5w40 motor oil. The materials were prepared using xanthan (XG) and XG esterified with acrylic acid (XGAC) as the polymeric matrix. LignoBoost lignin (LB), LB esterified with oleic (LBOL), stearic acid (LBST) and montmorillonite (CL) were added into XG and XGAC matrices to obtain the adsorbents. Adsorption experiments revealed that XG/CL/LBOL had the highest adsorption capacity at 46.80 g/g, followed by XGAC/CL at 45.73 g/g, and XG/CL at 37.58 g/g. The kinetic studies, employing the pseudo-second-order (PSO) model, indicated rapid sorption rates with a good correlation to experimental data. FTIR spectra analysis have evidenced the physical nature of adsorption process, involving interactions such as hydrogen bonding, van der Waals forces, and π–π interactions. Equilibrium data fitting to the Henry, Freundlich, and Temkin isotherm models showed that the adsorption occurs within materials diverse pore structures, enhancing oil retention. Structural parameters like density, porosity, and surface area were pivotal, with XG/CL/LBOL showing the most favorable properties for high oil adsorption. Additionally, it was found that the adsorption efficiency was influenced by the material's morphology and the presence of chemical modifications. This comprehensive evaluation highlights the potential of these novel adsorptive materials for environmental remediation applications, offering an efficient and sustainable approach to reducing degraded motor oil pollution. [ABSTRACT FROM AUTHOR]

This paper investigates the performance of a novel viscous passive damping solution to mitigate the chatter vibrations issue in the context of turning thin-walled cylindrical shell components for aerospace and other industries. This study involves the use of two different viscous fluids, motor oil and silicone oil, which have viscosities of 102 cSt and 350 cSt, respectively, to fill the in-house developed tube components with the aim of improving machining performance. Fast Fourier Transform (FFT) graphs were studied for chatter analysis, and surface roughness parameters such as average surface roughness (Ra) and mean roughness depth (Rz) were considered for studying the effectiveness of the viscous damping fluids. The results obtained with viscous damping were then compared with an undamped/unfilled tube with the same geometry. The cutting experiments showed that the motor oil reduced the excessive vibrations while silicone oil was able to eliminate them. For the tube with motor oil, the magnitude of the process sound at chatter frequency was reduced by 6.6 times as compared to an unfilled tube, whereas for the tube with silicone oil, the amplitude at chatter frequency was reduced by 14.8 times. Moreover, the surface quality of the tubes with motor oil and silicone oil shows almost equal improvement, indicating the need for future research on the type and amount of viscous fluids for implementing the concept in real cases. [ABSTRACT FROM AUTHOR]

Durability and reliability have been studied for decades through intensive trial-error experimentation. However, there are numerous fields of application where the costs associated with this approach are not acceptable. In lubricated machines with severe dynamic loads, such as high-power-density engines, simulation tools offer clear advantages over intensive testing. Prototypes and multiple scenarios can be cost-effectively simulated to assess different lubricants and engine configurations. The work presented here details the study of wear based on a validated elastohydrodynamic (EHD) simulation model of the connecting rod journal bearing. This model accounts for elastic deformation through a connecting rod finite element model (FEM). In addition, multiple lubricant rheological and tribological dependences, determined by specific experimental tests, are applied in the model through their interaction with the simulation software. Correspondingly, a novel wear algorithm is proposed to predict wear depth over time evolution along a proposed wear cycle based on the typical working ranges of high-performance engines. A final assessment is presented to compare 4 different ultralow-viscosity lubricants in their protective performance under severe conditions. The results show the evolution of the wear load and wear depth over the wear cycle. This evaluation is key to describing a lubricant selection procedure for high-power-density engines. [ABSTRACT FROM AUTHOR]

Oil monitoring plays an important role in early maintenance of mechanical equipment on account of the fact that lubricating oil contains a large amount of wear information. However, due to extreme industrial environment and long-term service, the data history and the sample size of lubricating oil are very limited. Therefore, to address problems due to a lack of oil samples, this paper proposes a new prediction strategy that fuses the domain shifts with uncertainty (DSU) method and long short-term memory (LSTM) method. The proposed DSU-LSTM model combines the advantages of the DSU model, such as increasing data diversity and uncertainty, reducing the impact of independent or identical domains on neural network training, and mitigating domain changes between different oil data histories, with the advantages of LSTM in predicting time series, thereby improving prediction capability. To validate the proposed method, a case study with real lubricating oil data is conducted, and comparisons are given by calculating the root-mean-square error (RMSE), mean absolute error (MAE), and mean relative error (MRE) with LSTM, support vector machine (SVM), and DSU-SVM models. The results illustrate the effectiveness of the proposed DSU-LSTM method for lubricating oil, and the robustness of the prediction model can be improved as well. [ABSTRACT FROM AUTHOR]

The lubricating oil system is a significant component of aviation engine lubrication and cooling, and the scavenge pipe is an essential component of the lubricating oil system. Accurately identifying and understanding the flow state of the scavenge pipe is very important. This article establishes a visualization test bench for a 45-degree inclined scavenge pipe, with upward and downward flow directions, respectively. The test temperature is 370 K, and a high-speed camera captures the changes in the two-phase flow inside the pipeline. Based on high-speed photography photos, we develop software for analyzing the flow characteristics of bubbles inside the tube and explore the influence of gas phase conversion velocity and liquid phase conversion velocity on the apparent velocity of bubbles inside the tube. Multiple algorithms were used to develop the model by combining machine learning with speed and accuracy to establish a data regression prediction model for the apparent velocity of bubbles inside the tube. Through calculation and analysis, it was found that the root mean square error of the prediction model using the BP neural network algorithm was the lowest, and the decision coefficient of the prediction model using the support vector machine algorithm was the highest. [ABSTRACT FROM AUTHOR]

This work describes the production of a novel biosurfactant produced by the bacterium Bacillus invictae UCP1617 cultivated using an alternative substrate and its use in the formulation of an eco‐friendly detergent. A factorial design was used to optimize agitation, temperature, and inoculum size in a mineral medium containing 1.5% corn steep liquor in 100‐mL shake flasks. The best conditions (175 rpm, 28°C, and 4% inoculum) were used to scale up biosurfactant production in a 50‐L bioreactor. Surface tension of the fermentation medium decreased from 69.5 to 30.2 mN/m within 72 h. The biosurfactant exhibited a critical micelle concentration (CMC) of 0.900 ± 0.08 g/L. The biosurfactant formed stable oil‐in‐water emulsions of motor oil and petroleum, achieving emulsification indices of 90.80% and 99.00%, respectively. An eco‐friendly detergent was formed that included biosurfactant at several different concentrations, 0.2 (wt) % hydroxyethyl cellulose and 0.2% potassium sorbate. The detergent remained stable under extreme conditions of pH, temperature, and salinity when stored for 90 days. The detergent was nontoxic to cabbage, cherry tomato plants, and the microcrustacean Artemia salina. A detergent formulation containing biosurfactant at the CMC completely dispersed motor oil in seawater at a 1:1 surfactant/oil (vol/vol) ratio and removed 99.21% of motor oil (20 mL) contained in 60 g of clayey soil. The detergent removed 98.42% of the oil adhered to a glass surface and removed 75.00% of motor oil adsorbed to a porous surface. The application of this biosurfactant as an environmentally friendly additive for remediation processes is feasible. [ABSTRACT FROM AUTHOR]

Diesel engines commonly suffer from oil contamination by fuel and other chemicals during operation and maintenance. This contamination alters the oil's lubricating properties, leading to increased wear, corrosion, and other potential problems. Therefore, it is crucial to understand how oil degrades and becomes contaminated due to different replacement strategies is crucial for both engine operators and manufacturers. This study focuses on the impact of fuel dilution on specific properties of engine oil under real-world operating conditions in a marine diesel engine. Oil samples were collected regularly from the crankcase of the engine fuel injection pump and tribological tests were performed. These tests aimed to assess how marine gas oil affects the oil lubricity performance and how it maintains its useful life. The results confirm that diesel dilution primarily affects the oil lubricating abilities as well as overall performance. [ABSTRACT FROM AUTHOR]

A study was carried out on benzyl alkoxycarbonyl methyl disulfides as multifunctional additives to lubricating oils. Results are given for testing the anticorrosion, anti-wear, anti-microbial action of previously synthesized benzyl alkoxycarbonyl methyl disulfides containing several functional groups. Efficiency was demonstrated for a series of benzyl alkoxycarbonyl methyl disulfides. Depending on their composition and structure, these disulfides improve the anticorrosion, anti-wear, and antimicrobial properties of oils. The antimicrobial properties of these compounds were studied as components of M-11 oil. The synthesized compounds in concentration 0.5-1.5 mass % enhance the resistance of mineral oil to biological damage and also display antimicrobial and antifungal activity. These compounds are more efficient than sodium pentachlorophenolate, which is a commonly used biocide. Testing in a four-ball friction machine indicates that these compounds possess anti-wear properties. Our derivatograph data on the thermal stability of these additives are in accord with the results of thermoanalytical testing of commercial additives. [ABSTRACT FROM AUTHOR]

Aviation lubricating oil, as the “blood of machine operation”, plays an important role in the lubrication, cooling, cleaning, sealing, rust prevention, and other aspects of aero‐engines, thereby ensuring the safe and stable long‐term endurance of aero‐engines under high‐speed and high‐temperature conditions. The thermal oxidation of aviation lubricating oil leading to decay is the most important factor causing lubricating oil failure, which will seriously affect the performance of aero‐engines and endanger flight safety. Here, we comprehensively summarize the oxidation mechanism of aviation lubricating oil, factors affecting thermal oxidation of aviation lubricating oil, evaluation methods for thermal oxidation of aviation lubricating oil, and antioxidants that inhibit thermal oxidation of aviation lubricating oil. We hope that this review can enhance readers' understanding of the thermal oxidation of aviation lubricating oil, stimulate broader interest, and promote more exciting development in this promising field. [ABSTRACT FROM AUTHOR]

Highlights Carbon fiber reinforced thermoplastic (CFRTP) composites, known for their excellent mechanical properties and environmental sustainability, are highly sought‐after in aerospace, energy, and many other fields. Grinding could be used to realize the high‐accuracy and low‐damage machining of CFRTP components. However, due to the temperature sensitivity and water absorption of CFRTP, dry and flood lubrication grinding could cause thermal damage and hygrothermal aging, respectively. In addition, these methods could lead to dust and excessive cutting fluids harmful to the environment. Addressing these bottlenecks, this study is the first to propose using oil‐on‐water minimum quantity lubrication (OoW‐MQL) to grind CFRTP. Experiments including various lubricating conditions and grinding parameters were performed to investigate the grinding performance. Experimental results showed that OoW‐MQL with the oil–water proportion of 1:1 outperformed the other lubricating conditions, achieving the best surface quality with the lowest grinding forces and temperatures. The optimal oil–water proportion remained almost unchanged under different grinding parameters. Furthermore, importance analysis using the extreme gradient boosting (XGBoost) algorithm demonstrated that oil–water proportion was the most critical factor affecting surface roughness. This study proves the feasibility of OoW‐MQL and provides technical guidance for high‐quality grinding of CFRTP. Oil‐on‐water minimum quantity lubrication (OoW‐MQL) was proposed to grind carbon fiber reinforced thermoplastic (CFRTP) composites. The experimental results of grinding forces, grinding temperatures, surface roughness and surface morphologies were analyzed, which proved that OoW‐MQL with oil–water proportion (1,1) had outstanding lubricating and cooling capability. The effect of grinding parameters on the optimal oil–water proportion was proved to be negligible through comparative tests under grinding parameters of high force and high temperature. Quantitative analysis using the extreme gradient boosting (XGBoost) algorithm identified the oil–water proportion as the most critical factor influencing surface roughness. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to prepare thymol-based deep eutectic solvents (DESs) and use them as lubricates for friction and wear tests to simulate the wear conditions of hybrid bearings. Design/methodology/approach: Through the characterization and analysis of the morphology of wear scars and the elemental composition of friction films, the tribological behavior and wear mechanism of sample materials as lubricants were investigated and the anti-wear mechanism of thymol-based DESs was discussed. Findings: The findings demonstrate that because of the formation of a fluid lubrication film and excellent kinematic viscosity, the lubrication effect of the prepared DES is improved by about 50% compared to the base lubricating oil. The prepared [Ch]Cl-thymol DES has a better anti-friction and lubrication effect than citric-thymol, EG-thymol and urea-thymol DESs, with an average friction coefficient of about 0.04. Originality/value: In this work, the friction reduction properties of thymol-based DESs were studied as lubricants for the first time, and the lubrication mechanism of sample materials was investigated. [ABSTRACT FROM AUTHOR]

Dyes are widely used in manufacturing of various consumer products for their ability to impart characteristic color. However, dyes are also one of the most important hazardous pollutants in this present day. Presence of hydroxyl, phosphate, ether, carbonyl and alkyl groups also enable bacterial extracellular polymers to function as biosorbent. In this study, negatively charged biosorbent EP-C1 produced by Gram-negative bacterium Ochrobactrum pseudintermedium C1 utilizing waste mineral lubricating oil has given different decolorization percentages for triphenylmethane cationic Malachite Green and azoic anionic Congo Red at neutral pH. Time wise absorbances from Ultraviolet-Visible Spectrophotometry has estimated maximum biosorption of Malachite Green after 300 min. Biosorption capacities have differed with initial dye concentrations, biosorbent dosages and contact time. Time taken by each dye to reach saturation has depended upon their charged bearing groups of each dye and biosorbent. Kinetic (pseudo first and pseudo second order) and diffusion (intra particle and liquid film) parameters in presence of different dye concentrations and biosorbent dosages were studied for understanding the biosorption mechanism. Morphological differences in chemical structure, chemical functional groups of EP-C1 and EP-C1 loaded dye was studied by Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy and Zeta potential measurements. A compiled overview on comparative mechanistic biosorption of Malachite Green and Congo Red dyes by a bacterial extracellular polymer in miniature laboratory shake flask experiments was done in this study. Newer advents on biological remediation of dyes with mineral lubricating oil as sole carbon source can add a new feather to the already available bioremediation techniques in mitigation of hazardous wastes. [ABSTRACT FROM AUTHOR]

The squeeze film damper (SFD) is a damping device that has been widely used in rotating machines. The SFD can effectively suppress rotor vibration and reduce transmitted forces. However, it would cause complex motions of the rotor system under specific operating conditions. This paper investigates the support structure of a high-pressure stage simulated rotor in an aircraft engine. A dynamic model of the SFD considering the effects of inertia and cavitation is established to investigate the influence of structural parameters on the stiffness and damping coefficient of the damper. Subsequently, a finite element model of the Jeffcott rotor–SFD system is developed to explore the effects of the structure parameters of the SFD on the critical speed, mode shapes, and other dynamic characteristics of the Jeffcott rotor–SFD system. Experimental tests are conducted to validate and refine the numerical calculations regarding the dynamic characteristics of the rotor–damper system. The results indicate that there is consistency between numerical simulations and experimental results. Within a certain range, enlarging the width of the damper can significantly increase the magnitude of the pressure distribution of the oil film. However, when the pressure amplitude increases to the saturation vapor pressure of the lubricating oil, the cavitation effect begins to manifest. As the width of the damper increases, both the stiffness coefficient and damping coefficient of the SFD are enhanced. Consequently, the vibration reduction effectiveness of the SFD is significantly improved. [ABSTRACT FROM AUTHOR]

The reliable operation of steam turbines is paramount for the sustained performance of electric power generation facilities. Any malfunction or breakdown in these high-speed rotating machines can lead to significant operational disruptions, causing energy production losses and jeopardizing safety. Lubricating oil leaks represent a common challenge faced by power plants, impacting operational efficiency, safety, and environmental sustainability. Despite extensive research efforts to mitigate oil leakage, challenges persist due to the unique design characteristics of power stations. This paper addresses the management of a major lube oil leak in Unit No. 2 of the Sumsel-5 Power Plant in Indonesia, focusing on innovative strategies for mitigation. The aim of this research is to assess the effectiveness of various rectification measures in reducing lubricating oil leaks in steam turbines. Methods employed include detailed inspections, analysis of oil quality, and implementation of targeted rectification strategies. The results demonstrate a significant reduction in the oil leakage rate, from approximately 67-68 liters per day to around 1.5-2 liters per day, following the implementation of rectification measures. This remarkable decrease of around 97.3% underscores the effectiveness of the strategies in mitigating the oil leakage problem. The implications of this study extend beyond operational efficiency to encompass safety and environmental protection. By reducing the volume of oil lost to leakage, safety hazards associated with fire accidents are mitigated, enhancing safety for plant personnel and equipment integrity. [ABSTRACT FROM AUTHOR]

Entropy generation analysis is a useful method for studying the relationship between heat transfer and pressure drop in flow boiling. The flow boiling process in an actual refrigeration system is inevitably affected by oil. Therefore, the effect of oil on entropy generation needs to be investigated. A new non-azeotropic ternary refrigerant mixture, R447A, was selected as working fluid. Subsequently, flow boiling entropy generation models of R447A with and without oil were established. The effects of individual parameters on entropy generation were investigated. The entropy generation per unit tube length under different conditions was proposed as the benchmark for comparison. The results show that there is an optimal mass flux corresponding to minimum entropy generation per unit tube length at a specific oil concentration, and optimal mass flux decreases with increasing oil concentration. The tube diameter also affects the optimal mass flux of the fluid with oil, which increases with decreasing tube diameter and is smaller than that without oil for the same diameter tube. When the oil concentration is 0–4.95%, the total entropy generation exhibits a decreasing trend. Therefore, within the scope of this research, the addition of oil is beneficial for reducing the entropy generation of heat exchangers. [ABSTRACT FROM AUTHOR]

In the paper, the consumption of fuels and lubricants is calculated according to the operating regimes of the naval energy installation. Consumption was analyzed from the perspective of reducing polluting emissions. The fuel and lubricating oil for the main engine and auxiliary engines were determined. The study was done for several navigation situations. [ABSTRACT FROM AUTHOR]

This document discusses the importance of lubricating oil and grease in reducing friction and wear in mechanical parts. It highlights the role of additives in enhancing the performance of lubricants and grease, such as improving wear resistance and thermal stability. The document includes 11 papers that cover various topics related to lubricants and grease, including the use of additives like layered double hydroxide and molybdenum disulphide, carbon-based nanomaterials, fullerenes, graphene, and WS2 nanoparticles. The papers explore the effects of these additives on the tribological properties of lubricants and grease, such as friction reduction and improved oxidation resistance. The document also discusses the synthesis and design of lubricant additives using computational simulations and quantitative structure-property relationship models. Overall, the document provides valuable insights into the research and applications of additives for lubricating oil and grease. [Extracted from the article]

Reusing industrial waste is one of the new tactics being used to fight the dumping of solid waste for environmental protection. In the current work, the waste polyurethane (WPU) was ground to a fine powder and used for reinforcement of devulcanized waste rubber/styrene butadiene rubber (DWR/SBR) blends. DWR/SBR/WPU composites were prepared using (0, 3, 6, 9, 15, 30) phr (parts per hundred of rubber) of WPU. It was hypothesized that the treatment of WPU with trimethylolpropane triacrylate (TMPTMA) and irradiated at 10 kGy would improve its compatibility with the DWR/SBR blend and, consequently, its reinforcement efficacy. The incorporation of 30 phr of treated WPU (TWPU) improved the tensile strength (TS) by 47.7% and 8.6% compared to neat DWR/SBR and composites containing 30 phr of untreated WPU (UWPU). In addition, the incorporation of TWPU improved other mechanical characteristics such as tear strength, hardness, and abrasion resistance. As a result of increasing polarity and cross‐link density within the DWR/SBR blend after the addition of polar WPU, the resistance to motor oil was improved. The outcomes are encouraging from the standpoint of the circular economy and help produce high‐performing, reasonably priced DWR/SBR composites for a range of industrial uses, especially in the floor tiles application. Highlights: Waste polyurethane (WPU) was activated using gamma irradiation in the presence of TMPTMA.The treatment of WPU improved its compatibility with DWR/SBR blend.The impact of WPU treatment on the properties of DWR/SBR blend was investigated.TWPU improved the mechanical properties of DWR/SBR blend more than UWPU.TWPU increased the motor oil resistance of DWR/SBR blend more than UWPU. [ABSTRACT FROM AUTHOR]

In this study, degummed and undegummed silkworm cocoon wastes were used to investigate their oil sorption capabilities for three kinds of oils, namely motor oil, vegetable oil, and crude oil. The laboratory-scale oil sorption results reveal that degummed silkworm cocoon waste has sorption capacities of 16.7, 15.8, and 14.2 g/g for motor oil, vegetable oil, and crude oil, respectively. It exhibits higher sorption capacities for these three oils compared with raw cocoons and cocoon scrap. These sorbents also exhibited excellent oil/water selectivity, retention capacity, and reusability. According to the large-scale experiment, the crude oil can be removed completely by degummed silkworm cocoon waste in 20 min, which shows that degummed silkworm cocoon waste could be considered a good alternative to synthetic sorbent materials applied to oil removal and recycling. [ABSTRACT FROM AUTHOR]

Enhancing lubrication across various tribological systems in the maritime industry is essential for improving safety, efficiency, and environmental sustainability. Al2O3 nanoparticles, employed as additives in lubricating oils, demonstrate favorable tribological properties including anti-wear and anti-friction characteristics. In this work, nano-scale γ-Al2O3 particles with different shapes, i.e., nanosheet, nanorod, nanosphere, and irregular-shaped nanoparticles, were prepared and calcinated forming the same crystalline phase with nanoscale size, which dispersed well in lubricating oil. The tribological properties of Al2O3 nanoparticles as lubricating oil additives were examined using block-on-ring wear tests, and the effects of the particle shape and particle concentration were investigated. The results indicated that the frictional properties are largely influenced by the particle shape and the concentration of the Al2O3 additives, with the optimal concentration being around 0.1 wt% for each shape. The lubricating oil with nanosheet additives presented the best tribological performance, followed by those with nanorod, nanosphere, and irregular-shaped Al2O3 nanoparticle additives. Al2O3 nanosheets as the lubricating oil additives reduced the stress effect on the friction surface because of their larger bearing area and are inter-particle-sheared during sliding due to the movement of friction pairs, which can further improve the tribological properties compared to other shapes. [ABSTRACT FROM AUTHOR]

Copyright of AIN Journal is the property of Arab Institute of Navigation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Polymer self-lubricating materials have advantages such as low friction coefficient, good wear resistance, and high work efficiency, giving them wide application potential in friction and wear. This work fabricated polymer-based self-lubricating materials by incorporating oil-loaded mesoporous silica nanoparticles (MSNs + YR1800) in the polypropylene resin (PP). The effects of different content of MSNs + YR1800 on the tribological and mechanical properties of the obtained self-lubricating composite materials were studied. The results indicate that the content of MSNs + YR1800 in composite materials significantly impacts their tribological properties. When the content of MSNs + YR1800 was 10 wt%, the coefficient of friction reduced to 0.09,which was 84.5% lower than for PP and 78.6% lower than for composite materials containing 5 wt% mesoporous silica nanoparticle (MSNs). Compared with pure PP, the wear rate decreases from 4.93 × 10−11 m3∙Nm−1 to 4.43 × 10−13 m3∙Nm−1, which is reduced by two orders of magnitude. The excellent tribological properties of composite materials are attributed to the high specific surface area, large pore volume, strong adsorption capacity, and high oil loading capacity of mesoporous silica nanoparticle as nanofillers. The MSNs + YR1800 release lubricants to form a lubricating oil film during the friction process under load conditions, preventing direct contact between the friction pair and the surface of the composite material. Compared with polymer-silica hybrid oil-loaded microcapsules, MSNs + YR1800 can effectively reduce lubricant leakage, prolong operation life, improve lubrication efficiency, and ensure the continuous and stable existence of lubricating oil films. [ABSTRACT FROM AUTHOR]

Copyright of Atomic Energy Science & Technology is the property of Editorial Board of Atomic Energy Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• A novel parameter is introduced to refine the refrigerant leakage theory. • The refrigerant leakage process carries a higher oil content is confirmed. • The effect of leakage mass flow rate on oil content is investigated. • The oil content is highest when refrigerant leaks from the high-pressure pipe. Refrigerant leakage is a situation that often occurs in refrigeration equipment such as heat pumps. However, certain alternative refrigerants, while exhibiting superior environmental performance, possess varying levels of flammability. The leakage of flammable refrigerants into confined spaces can pose a significant risk of explosion. The amount of lubricant in the leaking refrigerant will undoubtedly affect the flammability characteristics of the refrigerant. In this paper, the content of PVE32 oil in the leaking refrigerant during the operation of a heat pump was investigated. The results showed that, under the five leakage rate scenarios set up in the experiment, the oil concentration was highest when the leakage occurred at the condenser inlet and lowest when the leakage was at the evaporator outlet. During the leakage process of the experiment, as the mass flow rate of the leakage increased, the oil content in the early stage of the leakage increased, but the oil content in the late stage of the leakage decreased. The reasons for the change in oil content were analyzed by the oil circulation rate and the degree of phase separation. The decrease of the oil circulation rate and the change of the degree of phase separation were the key factors affecting the magnitude of the oil content as the leakage proceeded. The results of the study reveal the leakage characteristics of lubricating oil with refrigerant leakage. [ABSTRACT FROM AUTHOR]

In this paper, a semi-analytical calculation model for the coefficient of friction (COF) of single spherical protrusions is presented. It allows the prediction of the deformative friction part (μdef) and adhesive friction part (μadh) of the friction pairings steel ∣ polyethylene with ultra-high molecular weight (PE-UHMW) and polyoxymethylene (POM) ∣ PE-UHMW. The experimental studies included unlubricated friction tests, which served to determine the total COF (μtot), as well as tests being lubricated with silicone oil, from which μdef is obtained. Based on the verification tests, it could be shown that both states of lubrication result in the same deformation and that the relationship between the rear angle (ω) and μdef postulated in the calculation model is valid. Therefore, friction tests with segmented spheres were carried out, which allow a specific variation of the ω. It can be concluded that for both pairings the μdef is generally of minor significance (approx. 1/3 μtot) and the influence of the μadh predominates (approx. 2/3 μtot) the friction process. Furthermore the μtot decreases with increasing contact pressure especially in the low pressure range and depends on the form of motion (continuous and discontinuous). [ABSTRACT FROM AUTHOR]

In this paper, the influence of velocity slip and the Newtonian heating parameters on Williamson Nanofluid across a variable stretching sheet is studied. The basic fluid flow equations are turned into a system of coupled ordinary differential equations with appropriate conditions, which are solved numerically with the Keller-box approach. The outcomes show that, increasing Williamson parameter, due to the viscosity velocity of the fluid slowdown. As a result, it is noticed that the velocity slip parameter reduces Williamson Nanofluid velocity, while increasing shear stress, according to the results. Furthermore, it has been discovered that unlike velocity profiles, the slip influence is more pronounced on temperature and concentration profiles. Furthermore, the Newtonian heating parameter may be shown to have rising functions for velocity and dimensionless temperature. Newtonian heating has uses in the petroleum industry, heat exchangers, conjugate heat transfer around fins and solar radiation. It is discovered that the Joule heating parameter improves the thermal boundary layer thickness and slows down the velocity of the fluid, which aids in maintaining system temperature. Additionally, it has been found that the temperature profile exhibits a stronger slip effect compared with the velocity profile. To prepare toffee, chocolate and other delicacies as efficiently as possible, it is crucial to investigate the flow of Williamson fluids (such as drilling muds, clay coatings, various suspensions and some lubricating oils, thermoplastic melts, and a variety of colloids) in the incidence of heat transfer. The novelty of this paper is the effect of joule heating, Newtonian heating parameter and velocity slip on Williamson fluid velocity and temperature gradient. Furthermore, the heat and mass transfer rates are calculated for various parameters numerically and shown in tabular form. [ABSTRACT FROM AUTHOR]

We demonstrate the potential of unimorph beams equipped with macro fiber composites to integrate viscosity sensing and energy harvesting functionalities into a single device. The viscosity sensing component involves measuring the quality factor and resonance frequency peak associated with the second out-of-plane mode of vibration. We showcase the suitability of the present sensing device for liquids of wide range of kinematic viscosities from 1 to 1543.5 cSt. Following the quality factor-based sensing approach, the sensor reached a sensitivity of S = −0.0019/cSt. The amplitude-based sensing mechanism demonstrated a sensitivity of S = −3.3 mV/cSt. The viscosities of motor oil and glycerin, determined using the generated calibration curves, are found in close agreement with those obtained from a conventional rotational viscometer. The proposed sensing device holds great promise for online viscosity measurement, particularly for high-viscosity fluids, simple design, ease of operation, and partial self-sensing capability, thanks to energy harvesting. [ABSTRACT FROM AUTHOR]

This work establishes the dependences of the biological activity of synthesized dithio- and dithioseleno-containing spatially hindered phenols with α-methylbenzyl groups on the calculated values of the energy parameters of the molecules. For the studied compounds, the values of the electrophilicity index are calculated based on the obtained values of the ionization potentials and electron affinity. Using methods of multiple regression analysis, the dependences of the bactericidal and antifungal properties of the samples on two parameters were established: x1—the energy of the HOMO (highest occupied molecular orbital), and x2—the energy of the LUMO (lowest unoccupied molecular orbital) with a reliability of more than 93%. According to the equations derived based on the antimicrobial properties of bis[n-α-methylbenzyl-m-methyl-2-hydroxyphenyl] disulfides (selenides), three-dimensional graphs of functions were constructed, considering the boundary conditions of the zone of microorganism suppression around the hole on a scale of 0–3 cm. The obtained models show that changes in the energies of the LUMO (x2) have a greater effect on the zone of microorganism suppression than changes in the energies of the HOMO (x1), as indicated by the comparison of the coefficients' values for x2 and x1, respectively. Moreover, the degree of influence of changes in the energies of the boundary molecular orbitals on f antifungal properties is more significant than on bactericidal properties, based on the values of the coefficients of the equations for a mixture of fungi and bacteria at values x1 and x2. [ABSTRACT FROM AUTHOR]

• Refrigerant concentration in diffusion process is measured via refractive index. • Effects of temperature, pressure and initial concentration on diffusion are studied. • A new diffusion coefficient correlation of R32 in lubricating oil is developed. • The correlation predicts 90 % of experimental data within a deviation of ±10 %. R32 has been widely used in room air-conditioners, and its dissolution in lubricating oil can significantly affect the air-conditioner performance. The dissolved mass of R32 is determined by the diffusion coefficient which is related to the air conditioner working conditions, and thus a diffusion coefficient model that reflects the effects of the working conditions of temperature, pressure and initial concentration is needed. The purpose of this study is to develop a diffusion coefficient correlation of R32 in lubricating oil based on experimental investigation. The experiments of R32 absorption in lubricating oil are performed to measure refrigerant concentrations through refractive index, and then diffusion coefficients are obtained through the measured refrigerant concentrations. The experimental conditions cover the temperature of 35–50 °C, the pressure of 1.2–1.8 MPa and the initial refrigerant concentration of 0–8 %. The experimental results show that diffusion coefficients of R32 in the lubricating oil increase with the increase of temperature, pressure or initial refrigerant concentration. A new diffusion coefficient correlation which reflects the effects of temperature, pressure and initial concentration simultaneously is developed, and the proposed correlation could agree with 90 % of the experimental data within a deviation of ± 10 % and the average deviation is 5.4 %. [ABSTRACT FROM AUTHOR]

In order to evaluate the geotechnical characteristics of four types of fine-grained clayey soil, including clay with low plasticity (CL), calcium bentonite (CB), sodium bentonite (SB), and a mixture of 50% CL and 50% SB (CL-SB) from the effect of water, leachate and used motor oil (UMO) was used. Unconfined compressive strength (UCS), indirect tensile strength (ITS), standard compaction, Atterberg limit, and free swelling tests are performed. This results showed that the PI of SB, CB, CL, and CL-SB soils with leachate is 43, 25, 10, and 33% higher than water, respectively. The PI of SB, CB, CL, and CL-SB soils with UMO is 72, 66, 12, and 43% lower than water due to the low dielectric constant. Adding leachate compared to water caused a decrease in maximum dry density (MDD) for CL, CL-SB, SB, and CB by 2.6%, 4%, 6%, and 4.5%, respectively. Also, adding leachate and UMO reduces UCS and ITS of all soils. Due to SB soil's high cation exchange capacity, the changes in its mechanical and geotechnical characteristics were higher than in other soils. Finally, the increase in soil moisture during the sample construction decreased the soil strength due to the addition of leachate and UMO. [ABSTRACT FROM AUTHOR]

Nanofluids have attracted a lot of attention since their significant enhancement in thermal properties, however there are few reports on the study of the viscosity of nanofluids from an experimental point of view. In this work, the rheological behavior of functionalized multi-walled carbon nanotubes (F-MWCNTs) and coated with MoS2 (MWCNTs-MoS2) in a commercial palm oil as base fluid was evaluated. The purification and functionalization process of the MWCNTs was performed by acid leaching and investigated by FTIR, and stable nanofluids were prepared with MWCNTs concerning time. The rheological behavior of nanofluids with MWCNTs was performed as a function of temperature at different concentrations (0.1, 0.5 and 1% wt.). The effect of time, temperature, shear rate and shear stress versus shear rate were determined. The results indicate that the nanofluid behaves as a Newtonian fluid independently of the MWCNTs concentrations and temperatures evaluated. The viscosity index increases by 16% at a concentration of 1% wt. of F-MWCNTs and for nanofluids added with MWCNTs-MoS2 had significant effect on the effect of temperature. [ABSTRACT FROM AUTHOR]

The ingression of external contaminants probably causes spalling even severe failure, which may have significant effects on operation reliability of gas turbines. To investigate the evolution and determine the mechanism, artificial pits were made on the outer bearing ring raceway to simulate such failure. Comprehensive investigation into the base materials, macro and micro surface morphologies, service environments including lubricating oil analysis were conducted after disassembly of the engine. Also, during the 3-hours' operation, vibration and the metal debris monitoring were implemented. Results of this paper have demonstrated that the rolling contact fatigue spalling initiated from the edge of the dent with a distance of approximately 100 millimeters and extended along the balls' movement trace in the load-carrying area, while in the non-load-carrying area, no visible wear traces were found. The vibration and the metal debris analysis have demonstrated that the protruded edge was formed due to metal accretion around the dent, which later lead to stress concentrations, and it disappeared in the load-carrying area and induced spalling. This paper has discovered the initial failure morphologies and original site of contact fatigue spalling of ball bearings, and specified the mechanism through the simulation caused by foreign substance. [ABSTRACT FROM AUTHOR]

To address the challenge of lubricating oil creep loss in aerospace equipment, a biomimetic structure combining a wetting gradient with a geometric diversion pattern inspired by the peristome region of the Nepenthes pitcher plant is designed. A two-phase flow-field simulation is performed to investigate directional droplet transport on this biomimetic structure. Hydrothermal deposition and laser etching methods are then used to prepare surfaces incorporating this structure on a titanium substrate, and directional droplet transport is observed using high-speed photography. It is found that regions on this surface with a biomimetic structure region are superhydrophilic with a contact angle of 0°, while regions without any such structure are superhydrophobic with a contact angle of 159°. With increasing curvature of the biomimetic structural units, the self-actuation effect of the biomimetic structure on droplets decreases. The effects of the other structural parameters in the case of zero curvature is studied, and it is found that the droplet transport rate increases with increasing lateral spacing and longitudinal spacing between biomimetic structural units and decreases with increasing angle of inclination of these units and increasing droplet viscosity. The designed biomimetic structure is thus able to realize efficient directional transport of water and lubricating oil, with the transport rate being determined by the biomimetic structural parameters and the droplet viscosity. [ABSTRACT FROM AUTHOR]

Termites, beetles, and fungi are the main deteriorating agents on forest products and services within Ethiopia's industry and construction sectors. This study aimed to assess the natural durability of Pinus patula ssp tecunumanii lumber and the efficacy of used motor oil (UMO) in protecting against subterranean termites and fungal damage. Sixty-four lumber samples (stakes) measuring 2x5x50cm were treated with UMO using hot-and-cold dipping (HCD) and brushing methods, besides untreated controls. These samples were then installed at Bako and Adami Tulu Graveyard Research Stations for observation over four and a half years. At the final evaluation period, the mean damage caused by subterranean termites at Bako station on P. tecunumanii stakes treated with UMO using HCD, brushing, and untreated controls was 47%, 90%, and 96%, respectively, while fungal damage rates were 23%, 69%, and 42%, respectively. At Adami Tulu station, termite damage rates on treated stakes were 30% (HCD), 61% (brushing), and 63% (untreated), with fungal damage rates of 0%, 38%, and 53%, respectively. The UMO treatment using HCD method doubled the service life of P. tecunumanii lumber stakes compared to untreated controls. Therefore, applying used motor oil using the HCD method is recommended to enhance the durability of P. tecunumanii lumber for ground and moisture contact applications. [ABSTRACT FROM AUTHOR]

Hydro-viscous clutch has already become an inevitable choice for special vehicle transmission in the present and future. As a nonlinear system with a large hysteresis loop, its speed control performance is affected by input rotational speed, lubricating oil temperature, lubrication pressure, and other factors. The traditional control method cannot adjust the temperature and rotational speed, which will lead to problems of narrow speed range, poor rotational speed stability, and large dynamic load impact. In order to solve the above problems, this paper studies the control method of an integrated multi-parameter hydro-viscous speed control system (HSCS) in a controlled environment. Through the mechanism analysis of the law of HSCS, the influence law of speed and temperature during the system operation is found. The temperature closed loop based on model predictive control (MPC) is introduced to control the rotational speed, and then the traditional PID control results are compensated according to the speed closed loop. Next, a novel double closed loop control method of temperature and rotational speed for HSCS is formed. Finally, the simulating verification is carried out. Compared with the traditional control method, the design method in this paper can adjust the control parameters according to the temperature of the lubricating oil and the input rotational speed and effectively expand the domain of HSCS and the speed control stability. The effective transmission ratio is extended to 0.2~0.8, and the hydro-viscous torque and speed fluctuation under the engine rotational speed fluctuation are reduced by more than 30%. The novel control method of HSCS designed in this paper can effectively improve the influence of input rotational speed and lubricating oil temperature on the speed control performance of HSCS and can be widely used in nonlinear HSCS such as hydro-viscous clutch. [ABSTRACT FROM AUTHOR]

Development of energy-efficient lubricants is a way to reduce energy consumption for transportation, with the tendency to design molecules that are beneficial in reducing the viscosity of synthetic oils. Oligoether esters (OEEs), as a low-viscosity ester base oil, have characteristics such as simple synthesis and excellent lubrication effect, however, the application of OEEs in tribology field has rarely been investigated. The objective of the present study is to investigate the effect of structure on the lubricating performance of OEEs and to develop a predictive model for OEEs based on quantitative structure-property relationship (QSPR) through a combination of experiment and statistical modeling. Results showed that glycol chains contribute positively to lubrication with the ether functional groups increasing the sites of adsorption. Compared to branched-chain OEEs, straight-chain OEEs exhibited reduced wear, which was mainly due to the thicker adsorption film formed by the straight-chain structure. Furthermore, carbon films were detected on lightly worn surfaces, indicating that OEEs underwent oxidation during the friction process. Based on the results of principal component analysis (PCA) and partial least squares (PLS), it could be found that the predictive models of viscosity–temperature performance, thermal stability performance, coefficient of friction (COF), and wear volume (WV) performed well and robustly. Among them, COF and WV can be best predicted with an R2 of about 0.90. [ABSTRACT FROM AUTHOR]

To assess the effect of silicon content (SC) and test parameters on the lubricated wear of Zn-30 wt.% Al-3 wt.% Cu-(0.5–5) wt.% Si alloys, six quaternary alloys were produced by casting. Their wear properties were investigated at different ranges of contact pressure (CP) of 1–8 MPa and sliding velocity (SV) of 1–3 ms−1 for two different sliding distances (SD) of 20 km and 108 km. It was observed that Si addition (SA) improved the tribological properties of Zn-30Al-3Cu alloy, but an increase in the SC above a certain percentage (0.5%) adversely affected these properties. Therefore, Zn-30Al-3Cu-0.5Si alloy demonstrated the lowest friction coefficient (FC) and wear volume (WV) among the alloys tested. The correlations between the lubricated wear properties (FC and WV) of the alloys and test conditions (CP and SV) were made by non-linear regression analysis using the wear test data. Finally, the equations for the relationship between the wear properties of the alloys and the test parameters were determined. [ABSTRACT FROM AUTHOR]