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Ball bearings play a pivotal role in rotating machinery, making it crucial to detect their wear condition in real time for preventive maintenance. This paper proposes a novel method, involving one-dimensional convolutional neural network (1DCNN) and lubricating oil, which is sensitive to early abnormal wear, to intelligently predict the wear condition of ball bearings. To achieve that, an industrial-level gas turbine is used in the test to simulate the practical working conditions. During the machine's operation, the lubricating oil is sampled at different time intervals for spectral oil analysis (SOA), which is later utilized as the input data set. The 1DCNN model is then constructed and fine-tuned to extract its wear characters, and finally outputs a one-dimensional time-sequence feature vector of the SOA data, providing wear information for the upcoming hours. The predicted results have shown that the 1DCNN model can effectively predict the trend of wear condition with higher accuracy of over 97% and better generalization performance compared with the BP neural networks. Additionally, the validation test results have also verified the reliability of the 1DCNN model, which can be useful for manufacturing industries in reducing costly maintenance fees by early detection of potential failure. [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]

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]

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]

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]

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]

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]

Nano-graphene lubricating oil with appropriate concentration shows excellent performance in reducing friction and wear under different working conditions of diesel engines, and has been widely concerned. Lubricating oil has a significant impact on particulate matter (PM) emissions. At present, there are few studies on the impact of nano-graphene lubricating oil on the physicochemical properties of PM. In order to comprehensively evaluate the impact of nano-graphene lubricating oil on diesel engines, this paper mainly focused on the effects of lubricating oil nano-graphene additives on the particle size distribution and physicochemical properties of PM. The results show that, compared with pure lubricating oil, the total number of nuclear PM and accumulated PM of nano-graphene lubricating oil is significantly increased. The fractal dimension of PM of nano-graphene lubricating oil increases and its structure becomes more compact. The average fringe separation distance of basic carbon particles decreases, the average fringe length increases. The degree of ordering and graphitization of basic carbon particles are higher. The fringe tortuosity of basic carbon particles decreases, and the fluctuation of carbon layer structure of basic carbon particles decreases. Aliphatic substances in PM are basically unchanged, aromatic components and oxygen functional groups increase. The initial PM oxidation temperature and burnout temperature increase, the maximum oxidation rate temperature and combustion characteristic index decrease, and the activation energy increases, making it more difficult to oxidize. This was mainly caused by the higher graphitization degree of PM of nano-graphene lubricating oil and the increased content of aromatic substances. [ABSTRACT FROM AUTHOR]

R-Oxo hydroformylation processes on rhodium phosphite complexes developed at LLC «RN-RD CENTER» are described – selective production of n-butyral from propylene (R-Oxo I), production of a mixture of n-butyral and isobutyral in equal parts (R-Oxo II), selective production of n-pentanal from a mixture of linear butenes (R-Oxo III). A scheme for the hydroformylation of propylene with membrane separation of the catalyst from the heavy reaction products is described.The analysis of the direction of using C3–C5 oxosynthesis products as raw materials for the production of ester lubricants is carried out. [ABSTRACT FROM AUTHOR]

Rotary machines are continually vibrating. Any machine is unrealized in the absence of vibration. After a given amount of use, the equipment begins vibrating at a frequency greater than its natural frequency owing to degradation. Preventive maintenance is critical to avoiding unknown breakdowns. This article presents a comprehensive evaluation and diagnostic approach for two-stage gearboxes via ferrographical analysis. Using a direct reading ferrograph and a ferrogram maker, this study includes analyses of the size and shape of wear particles in lubricating oil in predicting system failure. The slide created with the ferrogram machine is then evaluated for analytical ferrography using the ferroscope. The study's analytical findings indicate that gearbox failure is caused by tooth wear and bearing failure, and that ferrography may be utilized successfully as a simple and reliable method for fault diagnostics. [ABSTRACT FROM AUTHOR]

The polymeric additives prepared from renewable feedstock having multifunctional applicability attracted significant attention in the lubricant industry. The present research focuses on a comparative study of multifunctional polymeric additives MPA-1 and MPA-2 synthesized via copolymerizing the triglyceride of olive oil and a homopolymer of stearyl methacrylate, respectively, using benzoyl peroxide as a free radical initiator. The synthesized additives were characterized by routine spectroscopic techniques like FT-IR and NMR spectroscopy. In contrast, the molecular weight was determined by gel permeation chromatography (GPC), and thermal stability was analyzed by thermogravimetric analysis (TGA). The additives were also evaluated for rheological analysis using Anton Paar MCR-72 by formulating the additives into mineral base oil (N-150) in three different concentrations, viz. 0.5%, 1.0% and 1.5% w/v. The formulated lubricant was analyzed for physicochemical parameters like viscosity index and pour point by standard ASTM methods. It was observed that both the MPAs additive shows improvement in the physicochemical and rheological properties of the base oil. Thus, the polymeric additives synthesized and formulated with mineral base oil show multifunctional applications. [ABSTRACT FROM AUTHOR]

In this paper, the tribological characteristics of an oil-soluble magnetic fluid additive under mixed lubrication are studied by experiments and numerical simulation. [bmim][FeCl4] is dissolved in CF10W-40 lubricating oil as a magnetic liquid additive, and its friction coefficient is tested by a point contact friction tester at different temperatures, rotational speeds and magnetic field intensities. The transition condition of lubrication state is obtained through analyzing the Stribeck curves based on the experiments, and the strength model of boundary film is established accordingly. A mixed lubrication model is established by substituting the boundary film strength model and the surface roughness model into the hydrodynamic lubrication model based on Reynolds equation. The results show that the magnetic solution as an additive can obviously reduce friction and wear, and the effect is more obvious under the condition of magnetic field. The boundary film strength model can accurately reflect the transition characteristics of lubrication state in the presence of boundary film, and the mixed lubrication model based on boundary film strength model can more precisely reflect the tribological characteristics of friction pairs, so this study provides a new theoretical method for the related research on the influence of boundary film on lubrication characteristics. [ABSTRACT FROM AUTHOR]

Carbazole derivatives can be used as antioxidants in the lubricating oil industry. The alkylation of carbazole with 2-chloro-2-methylpropane and 2-bromopropane catalyzed by anhydrous aluminum chloride was studied. Initially, 3,6-di-iso-propylcarbazole and 3,6-di-tert-butylcarbazole were using dichloromethane and dibromomethane as solvents at room temperature, respectively. The synthesis conditions were optimized. Subsequently, the effects of reaction time, catalyst dosage, and molar ratio of carbazole to alkylating agent were investigated, and orthogonal experiments were performed. The structures of the carbazole derivatives were characterized by Fourier infrared spectroscopy (FT-IR), mass spectrum (MS) and nuclear magnetic resonance spectroscopy (NMR). The thermal stability of the synthesized carbazole derivatives was investigated by differential scanning calorimetry (DSC). The carbazole derivatives were added into the lubricating oil with a mass fraction of 0.8% and the miscibility, stability and oxidation resistance of the mixed system were evaluated by mechanical stirring and a rotary pressure vessel oxidation test (RPVOT). The DSC results showed that there was good thermal stability for the carbazole derivatives. The mechanical stirring method revealed good solubility and stability for the mixture of oil and carbazole derivatives. The RPVOT results showed that isopropyl carbazole derivatives could increase the oxidation induction period of lubricating oil to 1.39 times, and tert-butyl carbazole derivatives could increase the oxidation induction period of lubricating oil to 1.91 times. The antioxidant effect of tert-butyl carbazole derivatives was better than that of isopropyl carbazole derivatives. [ABSTRACT FROM AUTHOR]

Poly (2-methacryloyloxyethyl phosphorylcholine) (PMPC), as a highly hydrophilic as well as biocompatible material, has been widely used in biomedical applications. In this study, the friction reduction and wear resistance of HXLPE were improved by grafting PMPC on its surface. However, the PMPC will be sheared off during friction, which is difficult to meet the long-term service requirements of artificial joints. This can be achieved by improving the lubrication environment to minimize PMPC shedding. To simulate the human lubrication environment, free PMPC (lubrication factor) and Cu2+ (transition group metal ion catalyst) were added to neonatal bovine serum (NBCS). When the friction pair consisting of grafted PMPC-modified HXLPE and Cu/ZrO2 ceramics is rubbed therein, the grafted PMPC interacts with the free PMPC, while Cu2+ catalyzes the oxidative hydrolysis of serum proteins into carbon-containing small molecules and adsorbs on the surface of the Cu/ZrO2 ceramics to form a carbon-rich lubrication layer. The composite lubrication layer consisting of grafted-free PMPC and carbon-rich lubrication layer provides good load-bearing and lubrication properties at the friction interface. And the wear rate is reduced by 45% compared to rubbing in deionized water. This technique can reduce the shedding of grafted PMPC state and improve the load-bearing performance of the interfacial lubrication layer, thus reducing the wear of HXLPE and prolonging the service life of the artificial joint. [ABSTRACT FROM AUTHOR]

Nonwoven microfibrous materials were electrospun from polystyrene solutions of concentrations 15-25 wt% in various solvents (DMF, THF, CHCl3, and EtOAc). Scanning electron microscopy found that fibers of various morphologies, both round and ribbonlike, with smooth and porous surfaces could be produced depending on the spinning solution parameters and process conditions. The average fiber diameter could be regulated in the range 0.5-20 μm. Addition to the spinning solutions of EtOH was shown to improve their rheological and electrophysical characteristics, to decrease the average diameter of the resulting fibers, and to improve their homogeneity. The obtained materials demonstrated superhydrophobic properties and high sorption capacity (up to 185 g/g) for motor and silicone oils. This enabled them to be considered effective sorbents for remediating spills of oil products from water surfaces. [ABSTRACT FROM AUTHOR]

Four hot-gas bypass defrosting configurations for CO2-NH3 cascade blast freezer for application in fish processing firm are numerically investigated. Due to the high moisture content of fish, defrosting is necessary after every 4 to 5 h of batch operation. A thermodynamic model for the cascade system and defrosting was developed to study various defrosting configurations formulated by rearranging the existing compressor to operate as a defrosting compressor and with the addition of an external defrosting compressor. From the simulation findings, it can be summarized that the conventional hot-gas bypass defrosting without defrost compressor is suitable for a high-capacity cascade refrigeration system with more than three evaporators. For low cooling capacity refrigeration systems, a defrosting compressor is necessary to elevate the temperature above the cascade condensing temperature. A dedicated defrosting compressor with a power consumption of 3.1 kW and a modified refrigeration/defrosting compressor with a power consumption of 6.8 kW can deliver 33.3 kW of heating at a temperature of +10 °C (45 bar). Incorporating a desuperheater between the main and defrosting compressors reduces compressor temperature and maintains the lubricating oil stability, without change in defrosting energy consumption and less exergy loss. The defrosting efficiency is obtained in the range of 39.7–42% which is in agreement with published literature. [ABSTRACT FROM AUTHOR]

Abnormal wear of the cylinder liner and piston ring in a marine diesel engine will lead to the failure of the diesel engine and colossal energy loss. Using lubricating oil additive with good anti-friction and anti-wear properties effectively inhibits the abnormal wear of cylinder liner and piston rings in diesel engine. The potassium borate/graphene (PB/GN) nano-composite lubricant additive suitable for a marine diesel engine was prepared in this study. Its tribological properties in 500 N base oil were investigated using a pin-on-disk tribotester under various loads and temperature. The frictional surface was comprehensively analyzed using field emission scanning electron microscopy (FESEM), energy dispersive spectrometer (EDS), x-ray photoelectron spectroscope (XPS) and Raman to explore the lubrication mechanisms of the PB/GN nano-composite additive. The results indicated that the PB/GN nano-composite additive could substantially improve the tribological performances of 500N base oil. This could be attributed to the good thermal conductivity of graphene and the tribofilms composed of C, FeO, Fe2O3 and B2O3 formed on the worn surface. The synergy of PB and GN enhanced the tribological performances of base oil. [ABSTRACT FROM AUTHOR]

Demetallization pretreatment is of great significance for the re-refining of used lubricating oil (ULO) by catalytic hydrogenation. Calcium-containing detergents colloidal stability, pyrolysis properties and kinetics studies have great significance for the demetallization pretreatment, re-refining, and resource utilization of ULO. The present study is focused on the pyrolysis mechanism and determining an accurate pyrolysis kinetic model for the removal of calcium from ULO using vulcanized calcium alkylphenolate (T-115B) colloidal as a model compound. Colloidal stability, pyrolysis process and thermal decomposition products have been studied by DLS, TEM, FTIR spectroscopy and XPS. The reaction energy for primary and secondary dissociation is calculated using the B3LYP-D3(BJ)/6-31g* method. The pyrolysis characteristics at different heating rates have been investigated by TG/DTA, and based on iso-conversional and master plot methods, E and kinetic equation have been determined, which revealed that the process can be divided into two distinct phases and the pyrolysis mechanism and function are necessarily described by a two-step model. The colloid was relatively stable when the temperature is lower than 395 K. When the temperature rises, compounds occur thermal decomposition, alkyl-CH2–S bond may be the trigger bond in the initiation process, and CaCO3 is the main degradation product. Based on iso-conversional methods (KAS and FWO) and master plot methods, values of E are determined as 96.67 and 100.78 kJ mol−1, respectively. And the pyrolysis reaction in stage 1 indicated that the most probable kinetic model followed an Fn mechanism with n = 1.39, and the second stage was also controlled by an Fn mechanism, but with n = 0.86. [ABSTRACT FROM AUTHOR]

The limited dispersion stability of graphene in lubricating oils and the high cost of chemical deposition method to prepare SiO2/GO composite materials. The samples were analyzed by X-ray diffraction, Raman spectroscopy, thermogravimetric analysis, transmission electron microscopy, scanning electron microscope. The test results demonstrate the ideal anchoring of SiO2 materials on GO surfaces. The tribological properties of SiO2/GO nanomaterials as the base oil additive were investigated using a four-ball tribometer. The addition of SiO2/GO nanocomposites to the lubricating oil enhances its lubrication performance, resulting in a significant reduction of 38.6% and 29.7% in friction coefficient and wear scar diameter compared to the base oil. The prominent lubrication properties of SiO2/GO nanocomposites are attributed to their excellent dispersion and ultra-thin shape, which enable them to enter contact surfaces and act as protective films that prevent direct contact with each other. Compared with the previous research, the rheology was innovatively introduced, the rheological test of the lubricating oil was conducted, and its results were correlated with the friction data. The rheological data were fitted to analyze and understand the lubrication mechanism, providing a novel perspective for studying lubricating oils. SiO2/GO composites exhibited excellent performance due to their low cost and lubrication, which is the future direction of commercial lubricant development. It can be extensively utilized in the domains of automotive engines and heavy machinery, which exhibits promising potential applications. SiO2 nanomaterials were grown fully on the layered GO nanoflakes prepared by the sol–gel method, giving rise to a novel microstructure of SiO2/GO as additives materials for lubricating oil. The character of the SiO2/GO is easily deposition on friction interface. [ABSTRACT FROM AUTHOR]

This document is a guest editorial from the journal Friction, focusing on the special issue of Artificial Intelligence (AI) and emerging computational approaches for tribology. Tribology research, which studies friction and wear, has traditionally relied on extensive experimentation. However, AI and computational approaches offer new opportunities to explore complex processes in tribology and push the boundaries of research. The special issue includes 15 papers covering various aspects of AI and machine learning in tribology, such as wear assessment, lubrication performance, contact wear prediction, and composite materials design. These articles highlight the transformative impact of AI in tribology research and provide valuable insights for future innovations. [Extracted from the article]

Bio-based natural wastes could be considered eco-friendly alternatives to conventional fillers for enhancing the properties and reducing the cost of final rubber products. Thus, in the present research, EPDM/NBR rubber blend composites filled with kaolin and mixed with rice husk fibers (RHFs) were prepared. Homogeneity of the EPDM/NBR blends was improved by the incorporation of maleic anhydride (MAH) as a compatibilizing agent (1 phr), as evidenced by scanning electron microscopy (SEM). Of all EPDM/NBR blend ratios investigated, the 25/75 blend revealed good mechanical properties, thermal stability, and the least weight swell at equilibrium (Q%) in motor oil and brake fluid. EPDM/NBR/kaolin (25/75/30) blend vulcanizates containing RHFs at various loadings demonstrated a significant improvement in swelling resistance, primarily in motor oil and brake fluid, accompanied by a slight reduction in the mechanical properties at high RHFs content. That was complemented by the enhancement of thermal stability of the rubber blends, as demonstrated by TGA analysis. Among the filler types investigated (RHFs, silica ash (SA), rice husk silica (RHS), and kaolin), RHFs exhibited the best swelling resistance of the composite vulcanizates in motor oil and brake fluid. In addition, RHS could be used successfully as a supporting filler for carbon black-reinforced EPDM/NBR composite vulcanizates because it enhanced their thermal stability and swelling resistance in the motor oil. [ABSTRACT FROM AUTHOR]

This paper reports the results of an experimental investigation of graphene particle suspensions in lubricating oil, ethylene glycol and glycerol-based fluids. Graphene particles of different specific surface area show variation in the viscosity depending on the shear rate and the temperature. The lubricating effect, e.g., reduction in the viscosity compared to the base fluid, is observed for the concentration (below 0.4 mass%) in lubricating oil and glycerol. In the range of parameters studied (e.g., concentration below 1 mass% and temperature up to 80 °C), the activation energy slightly decreases. The enhancement of viscosity with graphene volume fraction is larger for ethylene glycol. [ABSTRACT FROM AUTHOR]

As a sustainable management of fossil fuel resources and ecological environment protection, recycling used lubricating oil has received widespread attention. However, large amounts of waste lubricating-oil regeneration wastewater (WLORW) are inevitably produced in the recycling process, and challenges are faced by traditional biological treatment of WLORW. Thus, this study investigated the effectiveness of electrocoagulation (EC) as pretreatment and its removal mechanism. The electrolysis parameters (current density, initial pH, and inter-electrode distance) were considered, and maximal 60.06% of oil removal was achieved at a current density of 15 mA/cm2, initial pH of 7, and an inter-electrode distance of 2 cm. The dispersed oil of WLORW was relatively easily removed, and most of the oil removal was contributed by emulsified oil within 5–10 μm. Gas chromatography–mass spectrometry (GC–MS) analysis revealed that effective removal of the biorefractory organic compounds could contribute to the improvement of biodegradability of WLORW. Thus, the 5-day biochemical oxygen demand/chemical oxygen demand ratio (BOD5/COD) was significantly enhanced by 4.31 times, which highly benefits future biological treatment. The routes of WLORW removal could be concluded as charge neutralization, adsorption bridging, sweep flocculation, and air flotation. The results demonstrate that EC has potential as an effective pretreatment technology for WLORW biological treatment. [ABSTRACT FROM AUTHOR]

Understanding the importance of reclaiming water from a huge oily wastewater stream generated during the drilling of oil in the petroleum industry and mitigating membrane fouling, a polymeric-inorganic nanocomposite membrane was fabricated with self-cleaning properties. The photocatalytic TiO2 nanoparticles were embedded in the polyvinylidene fluoride (PVDF) matrix during wet phase inversion. To enhance the separation potential and photocatalytic activity of TiO2 nanoparticles, a conjugated polypyrrole (PPy) was grown on the membrane through oxidative polymerization leading to an active layer composed of PPy@TiO2 nano-photocatalyst. The study of membrane wettability revealed the hydrophilic and underwater superoleophobic nature of the PPy@TiO2/PVDF membrane. The PPy@TiO2/PVDF membrane was applied for treating water-containing emulsified oily feed. Different types of feeds contaminated by different oils such as motor oil, diesel oil, and crude oil were studied. The separation efficiency of the PPy@TiO2/PVDF membrane stayed above 99% as the membrane allowed only water to permeate while oil was rejected. The permeate pure water flux was found to be dependent upon feed pressure and the nature of oil in the feed. While keeping the separation efficiency constant at 99%, the flux was decreased with increasing concentration of oil in the feed which is attributed to the fouling of the membrane. The fouled membrane was photo-catalytically cleaned by exposing the fouled PPy@TiO2/PVDF membrane to solar-simulated visible light as the surface features of the cleaned membrane completely resembled that of the pristine PPy@TiO2/PVDF membrane. [ABSTRACT FROM AUTHOR]

Highlights: Successfully solves the key issue of tribovoltaic nanogenerators (TVNGs) lifetime (90,000 cycles) and improves its output current density (754 mA m−2) simultaneously. Conductive polar liquid with MXene as additive is proposed as the dominant factor in enhancing the electrical output performance and durability of TVNG simultaneously. The mechanism of lubricated TVNG with enhanced output performance is explained from the perspective of solution polarity at the first time. Mxene solution exhibits universality in different types of semiconductor systems (Cu and P-type Si, and Cu and N-GaAs as material pairs). Tribovoltaic nanogenerators (TVNGs) have the characteristics of high current density, low matched impedance and continuous output, which is expected to solve the problem of power supply for small electronic devices. However, wear occurrence in friction interface will seriously reduce the performance of TVNGs as well as lifetime. Here, we employ MXene solution as lubricate to improve output current density and lifetime of TVNG simultaneously, where a high value of 754 mA m−2 accompanied with a record durability of 90,000 cycles were achieved. By comparing multiple liquid lubricates with different polarity, we show that conductive polar liquid with MXene as additive plays a crucial role in enhancing the electrical output performance and durability of TVNG. Moreover, the universality of MXene solution is well demonstrated in various TVNGs with Cu and P-type Si, and Cu and N-GaAs as material pairs. This work may guide and accelerates the practical application of TVNG in future. [ABSTRACT FROM AUTHOR]

In response to the continually increasing thermal load caused by the rising gas temperature in the inlet of radial-flow turbines, this paper proposes the use of axial hole air-entraining cooling to cool the turbine shaft and turbo wheel back-disc. The cooling effect of this technique, as well as its influence on the aerodynamic performance of turbines, were investigated through numerical simulations. The results demonstrate that the axial hole air-entraining cooling technique can significantly improve the local cooling efficiency of the turbine back-disc. Under a blowing ratio of 0.25 %, the local cooling efficiency increased by 154 %, and the temperature decreased by up to 233 K. The maximum temperature on the surface of the turbine shaft at the floating bearing location decreased significantly, thus reducing the coking risk of the lubricating oil. When the blowing ratio was within 0.5 %, the impact of this cooling technique on the overall turbine performance was negligible. [ABSTRACT FROM AUTHOR]

Wear particles are generated in the mechanical system due to different modes, such as abrasion, adhesion, erosion, oxidation, corrosion, and severe sliding. Wear particle analysis is a non-intrusive tool to monitor the condition of lubricated components. The study of wear particles gives information related to the size of particle, concentration and quantity, material composition and size distribution, from which operating wear mode can be predicted to observe the state of a component. This paper has discussed the case study for wear particle classification using different parameters. Experimentation has been carried out to observe the nature of wear and wear particle classification by operating gearbox for 500hrs. Lubrication is essential for correct functioning of gearbox therefore, ferrographic analysis is carried to measure the concentration of wear particle through lubricating oil. Olympus Stream Basic Software is used to analyze ferrogram slides to measure different parameters area, perimeter, aspect ratio, shape factor, mean radius, and mean color intensity values of wear particles. Area and perimeter of normal rubbing wear is used to classify them into small-, medium-, and large-sized particles. [ABSTRACT FROM AUTHOR]

This study examines the abrasive wear behavior of nano-sized steel scale on the CuZn35Ni2 Soft material. CuZn35Ni2 Soft material was used as a sample, and the three-body wear mechanism formed by nanoscale particles mixed with lubricating oil was investigated using a ball-on-flat tester. Three different loads, three different sliding speeds and three different environment variables were used in the experiments. A lubricant containing 0.15 and 0.3 wt.% nanoscale and a non-abrasive lubricant was used to form the medium. The experimental results were obtained as mass loss, wear depth and friction coefficient and the wear surfaces were examined using scanning electron microscopy/energy-dispersive x-ray spectroscopy (SEM/EDX). The analysis of variance method was used to determine the effect of independent variables on the results. As a result of the study, it was concluded that the most effective parameter for mass loss and CoF was the environment, and the most effective parameter for the depth of wear was the load. It was concluded that there might be a difference of up to 10% in the coefficient of friction between the experiments and the predicted values. Still, in general, the predicted values and the experimental results agree. [ABSTRACT FROM AUTHOR]

The great demand on the energy makes the attention toward modifying lubricating oil. This work tends to prepare the following copolymers; octadecylmethacrylate-co-dodecene (CP1) and octadecylmethacrylate-co-hexadecene (CP2) by free radical solution polymerization using laboratory prepared octadecylmethacrylate monomer with either 1-dodecene or 1-hexadecene. The same monomers also used to prepare their polymers nanocomposite (NP1, NP2) with 1% of nanomontmorolonite by emulsion polymerization. The structures of the prepared polymers and their nanocomposite were elucidated by FTIR, 1HNMR, TGA, DSC, TEM and DLS. These polymers were used as pour point depressant, flow improver and viscosity modifier and showed high efficiency. After comparison of the data of the polymers and their nanocomposite, the nanocomposite give the best results where the pour point decreased from 0 °C to − 18, − 27, − 24 and − 33 °C for CP1, CP2, NP1 and NP2 respectively at the optimum concentration 10,000 ppm. On the other hand the viscosity index increased from 86.57 to 93.25, 92.41, 94.17 and 93.103 for CP1, CP2, NP1 and NP2 respectively, the apparent viscosity increased from 55.863 to 69.31, 119.41, 111.28, and 166.89 cP also the yield stress increased from 652.19 to 1076.3, 1074 and 1480 D/cm2 for CP1, CP2, NP1 and NP2 respectively. [ABSTRACT FROM AUTHOR]

High-temperature ablation is a common failure phenomenon that limits the service life of the transmission parts on heavy-duty machines used in heavy load, high temperature, high shock conditions due to in-sufficient supply of lubricating oil and grease. Traditional self-lubricating coatings prepared by inorganic, organic or organic-inorganic hybrid methods are prone to be oxidated at high temperatures to lose their friction reducing function, so that it is difficult to meet the engineering requirements of high-temperature lubrication. We design viscoelastic polymer coatings by a high-temperature self-lubricating and wear-resistant strategy. Polytetrafluoroethylene (PTFE, Tm = 329 °C) and polyphenylene sulfide (PPS, Tg = 84 °C, Tm = 283 °C) are used to prepare a PTFE/PPS polymer alloy coating. As the temperature increases from 25 to 300 °C, the PTFE/PPS coating softens from glass state to viscoelastic state and viscous flow state, which is owing to the thermodynamic transformation characteristic of the PPS component. Additionally the friction coefficient (µ) decreased from 0.096 to 0.042 with the increasing of temperature from 25 to 300 °C. The mechanism of mechanical deformation and surface morphology evolution for the PTFE/PPS coating under the multi-field coupling action of temperature (T), temperature-centrifugal force (T-Fω), temperature-centrifugal force-shearing force (T-Fω-Fτ) were investigated. The physical model of "thermoviscoelasticity driven solid-liquid interface reducing friction" is proposed to clarify the self-lubricating mechanism determined by the high-temperature viscoelastic properties of polymers. The high-temperature adjusts the viscosity (η) of the coating, increases interface slipping and intensifies shear deformation (τ), reducing the friction coefficient. The result is expected to provide a new idea for designing anti-ablation coatings served in high temperature friction and wear conditions. [ABSTRACT FROM AUTHOR]

In this present work, the coefficient of friction (COF) at the interface of punch and ultra-thin sheet materials of AA1050, C101 and SS304 grades was evaluated under dry and lubricated conditions using a sub-sized stretch forming test setup and tribometer. The finite element (FE) models of the stretch forming process and stamping of serpentine shaped micro-channels were developed incorporating the experimentally evaluated COF and the anisotropic properties of all the three materials. It was found that the deformation load during the stretch forming process was influenced by the COF; however, the ratio of interface contact pressure to strength coefficient of the material at the inflection point was found to be negligible. The strain path during the stretch forming process shifted close to equi-biaxial deformation mode with more uniform strain distribution and delayed localized necking under the application of Teflon tape and lubricating oil. Moreover, the successful stamping of micro-channels on these ultra-thin sheets was demonstrated under both dry and lubricated conditions, and the effect of lubrication on the formability of the channel was presented in terms of peak load, maximum thinning and thickness distribution along the channel wall. [ABSTRACT FROM AUTHOR]

Full-ceramic ball bearings are widely used in aerospace, gas engines, and extreme working conditions. The research on vibration characteristics of full-ceramic ball bearings under different pre-tightening forces and oil supply rates is relatively rare. In this paper, silicon nitride 6206 full-ceramic deep groove ball bearing is taken as the research object, the experiment of lubrication vibration characteristics of full-ceramic bearings is carried out on a bearing vibrometer by changing different pre-tightening forces and lubricating oil supply rates with the control variable method, the dynamic model of full-ceramic deep groove ball bearing under lubrication condition is established, and the influence of factors such as lubricating oil drag force, lubricating oil film thickness, rolling friction force, and pre-tightening force on bearing vibration are analyzed in essence. The experimental results show that the large vibration ratio of the bearing in the state of lack of oil is caused by insufficient oil supply, and when the oil supply rate is too high, the rolling body is dragged by too much drag force, which leads to an obvious increase in bearing vibration. The similarity between the solution signal and the measured signal of the dynamic model of full-ceramic bearing considering the drag force of the rolling body under different lubrication conditions is over 95%, which proves the reliability and accuracy of the dynamic model. [ABSTRACT FROM AUTHOR]

This study used a regression model, experimental data from a viscosity measurement device, and a computational technique to investigate the relationship between lubricant viscosity and surface-attached adhesion rates. Three types of used lubricants were identified and evaluated using viscosity and surface adhesion measuring instruments using three different sizes of steel balls, namely 3 mm, 3.5 mm, and 4 mm. The experimental results were then analysed using a simple linear regression model with parameter estimation. At a significance level of 0.05, the results revealed that the lubricant viscosity and the rate of surface adhesion were linearly correlated. The results of this research could be utilized by industry to control the usage of lubricating oil in industrial parts, make judgments about changing or analysing the quality of the heat-reducing lubricant at the interface between mechanical components, and so on. To maintain lubrication efficiency and increase the service life of industrial parts. As a result of fulfilling this desired goal, the regression equations generated during this study can be used to estimate surface-attached adhesion rates in other circumstances. The viscosity range utilised in this case study corresponds to the normal viscosity of the unused lubricant. The surface-attached adhesion rate can thus be accurately selected by manufacturers, and the lubrication effectiveness can also be monitored. This is another indirect waste reduction in the manufacturing chain. [ABSTRACT FROM AUTHOR]

In the present work, bamboo-shaped Oxidized Multi-walled Carbon Nanotubes (O-MWCNT) synthesized through catalytic decomposition of natural gas were reinforced in a silica matrix to achieve a robust O-MWCNT-silica aerogel. The synthesized aerogel was hydrophobisized through surface modification with trimethylsilyl chloride for its application as an oil spill cleaning agent. The developed aerogel possesses high specific surface area of 795 m2/g evaluated from Brunauer–Emmett–Teller (BET) model, with a pore size of 11.2 nm. The density of the O-MWCNT-silica aerogel was 0.02 g/cc with a porosity of 87%, confirming its ultra-light and high porosity nature. Moreover, the synthesized aerogel exhibited hydrophicity, with a water contact angle of 136.2°. The sorption capacity of the aerogel investigated using motor oil projected an oil sorption capacity of about 13.72, 16.70, and 19.48 g/g at 25, 30, and 40 °C, respectively. The oil sorption kinetics revealed that the oil sorption on to the O-MWCNT-silica aerogel followed the pseudo-second-order kinetics with the particular correlation coefficients (R2) of 0.9898. Furthermore, the aerogel can be regenerated by the treatment with acetone and sustain its oil sorption capacity up to 5 regeneration cycles. Thus, the outstanding characteristics and hydrophobicity of the synthesized aerogel in this work establish itself as a capable adsorbent for oil spill cleaning. [ABSTRACT FROM AUTHOR]

In order to develop a method for assessing the service life, the values of kinematic viscosity at temperatures of 100 °C and minus 40 °C, acid number and amount of sediment insoluble in isooctane, critical load and the wear scar diameter, height and time of destruction of the foam column, as well as the tensile strength of IRP-1316, IRP-1287 and 51-1434 sealing rubbers of aviation oils were determined in the state of delivery and after oxidation at temperatures of 200, 225, and 240 °C. The influence of water in concentrations of 0.01, 0.1 and 1% on the performance properties of oils, was estimated. Based on the mathematical dependences obtained for the property values on the time and temperature of oxidation, the estimation of the operating time of the standard oil for aircraft gas turbine engines and helicopter gearboxes was carried out [ABSTRACT FROM AUTHOR]

A review of scientific and patent data on the hydroformylation of lower C2–C4 olefins in the oxo synthesis of oxygen-containing products is presented. Industrial and prospective catalytic systems based on organometallic compounds of cobalt and rhodium modified with phosphine and phosphite ligands and also industrial technological schemes involving such catalytic systems are examined. [ABSTRACT FROM AUTHOR]

Friction and wear are ubiquitous, from nano-electro-mechanical systems in biomedicine to large-scale integrated electric propulsion in aircraft carriers. Applications of nanomaterials as lubricating oil additives have achieved great advances, which are of great significance to control friction and wear. This review focuses on the applications of nanomaterials in lubricating oil and comprehensively compares their tribological characteristics as lubricating oil additives. Statistical analysis of tribology data is provided and discussed accordingly; moreover, the interaction between nanomaterials and sliding surface, lubricating oil, other additives, and synergistic lubrication in nanocomposites are systematically elaborated. Finally, suggestions for future research on nanomaterials as lubricating oil additives are proposed. Hence, this review will promote a better fundamental understanding of nanomaterials for lubricating oil application and help to achieve the superior design of nanoadditives with outstanding tribological performances. [ABSTRACT FROM AUTHOR]

The inadequate management and final disposal of lubrication oil waste from the maintenance of artisanal fishing vessel engines can affect the marine environment. In the Peruvian case, there is no evidence suggests that this waste is managed at all, and there is no regulation regarding this matter. Therefore, this study aims to implement an oil waste management system for artisanal fishing vessels in the Bay of Ancón in Lima, Perú. A collector prototype was installed according to oil waste generation estimates. Further, a management protocol was designed based on the provisions from Rule 38 of Appendix I of the MARPOL 73/78 Convention and the guidelines issued by the Peruvian Ministry of Transportation and Communications for the treatment of oil waste from merchant vessels. Before installing the prototype, there was no evidence of oil waste collection. During collection operations, in the stage before the installation of the collector prototype, 1795 L of waste oil was collected in 12 months. After the installation of the prototype, 3276 L of waste oil were collected in 11 months. According to our estimates, we collected 82.75% of oil waste produced by the entire artisanal fishing fleet in Bay of Ancón. This has been the first management system implemented in Perú, and for the first time, it has showed the final disposal of lubricating oils and other oil waste generated by artisanal fishing craft. [ABSTRACT FROM AUTHOR]

Aluminum alloy thin-walled shells with corner are important components of aircraft lubricating oil tank for protective. The existing process mainly adopts cold stamping combined with manual multi-pass straightening and shape correction. Due to its asymmetrical shape and corner, there are serious defects such as wrinkling and springback during stamping, which restrict the mass production of this kind of products. In this paper, the forming mechanism of defects and the influence of process parameters on it were investigated numerically and experimentally. The results demonstrated that the wrinkling concentrated on the side wall of workpiece was caused by more feeding and metal accumulation in local areas due to stress concentration. There was obvious thinning at the small diameter edge (SDE) of workpiece which can reach 10.0% locally. The springback in different areas of workpiece varied greatly. Massive positive springback occurred at the SDE and the large diameter edge (LDE), and a small amount of negative springback occurred at the top left of the workpiece due to insufficient material extension. The wrinkling and springback can be ameliorated by increasing the blank holder force (BHF) while the thinning will be aggravated. Besides, the increase of friction coefficient and die closing pressure (DCP) can also reduce the wrinkling and springback, respectively. For the workpieces in this paper, the forming defects can be greatly improved within the following process parameters: the BHF of 15 to 20 kN and the stamping speed of not less than 20 mm/s and the DCP of above 350 kN. [ABSTRACT FROM AUTHOR]

We proposed a procedure for the simultaneous determination of viscosity improvers and detergent additives in synthetic oils by gel permeation chromatography, including the preliminary liquid extraction of polar additives, solid-phase extraction of polymer additives on silica modified with magnesium oxide from oil raffinate, and the subsequent determination of analytes. The procedure was used to determine viscosity improvers and detergent additives in fresh and used synthetic motor oils, to control the quality of oils at different stages of operation, and to monitor the degree of purification of oils during their regeneration. In-process monitoring of additive concentrations during the operation of automotive equipment enables the timely control of the dynamics of engine oil degradation throughout its use and proper recommendations for its replacement in the system. The procedure was tested in the analysis of fresh and used multigrade synthetic motor oils Shell Helix Ultra 5W-30 and TP MAX Total 10W-40 and fresh multigrade synthetic motor oil Shell Rimula R5M 10W-40. [ABSTRACT FROM AUTHOR]

Petroleum products are the target of fraudulent practices due to their high commercial value. The aim of this study is to provide a new analysis system to assess motor oil adulteration. For this purpose, Laser Induced Fluorescence (LIF) spectroscopy was exploited coupled with chemometric tools to detect motor oil adulteration by three types of cheap motor oils. Principal Component Analysis (PCA) was able to distinguish samples in three groups according to the type of adulterant. Besides, Partial Least Squares Regression (PLSR) was exploited to determine the percentage of adulteration. The best model was obtained with a regression coefficient of 0.96, Root Mean Square Error of Prediction (RMSEP) of 2.83, Standard Error of Prediction (SEP) of 2.83 and Bias of 0.40. The main results of this work provide new analysis system using the combination of LIF spectroscopy combined to PCA and PLS as an efficient and fast method for motor oil analysis. [ABSTRACT FROM AUTHOR]

The present study aims to evaluate the growth potential of the P. aeruginosa ATCC9027 strain with molasses as the sole carbon source to produce rhamnolipids. The influence of the cultivation time and substrate concentration on biosurfactant production was investigated by using a complete 3-level factorial design, with the rhamnolipid concentration as the variable response. The strain was able to produce the biosurfactant in all design conditions tested, producing 758.04 mg/L rhamnolipids with 7% v/v substrate concentration in a cultivation time of 120 h. The substrate concentration used in the cultivation step directly influenced the biosurfactant production, and, even with the decrease in biomass growth, the biosurfactant production continued to increase. High Performance Liquid Chromatography (HPLC) revealed the presence of 62.3% mono- (RL1) and 37.6% di-rhamnolipids (RL3). The stability tests showed that the biosurfactant has good performance in extreme conditions of temperature, pH and saline concentration. The emulsification index was also evaluated for several oils and hydrocarbons, obtaining emulsification rates of up to 84.9% for the burnt motor oil. In addition, rhamnolipid showed a good ability to remove spilled oil from the sand, removing 58.51% of burnt motor oil and 70.09% of post-frying soybean oil. The results indicate that molasses, an agro-industrial residue abundant in Brazil, can be used as the only carbon source for quality rhamnolipid production when under optimized conditions, therefore presenting itself as a management option for this residue and, at the same time, providing the production product with high added value. [ABSTRACT FROM AUTHOR]

In this study, the direct intercalation of gemini ionic liquids (ILs) with different alkyl chains into the bentonite (BT) interlayer as a high-performance lubricating additive for base oil 500SN was investigated. The purpose of modifying BT with an IL is to improve the dispersion stability and lubricity of BT in lubricating oil. The dispersibility and tribological properties of IL—BT as oil-based additives for 500SN depend on the increase in interlamellar space in BT and improve as the chain length is increased. More importantly, the IL—BT nanomaterial outperforms individual BT in improving wear resistance, owing to its sheet layers were deformed and sprawled in furrows along the metal surface, thereby resulting in low surface adhesion. Because of its excellent lubrication performance, IL-modified BT is a potential candidate for the main component of drilling fluid. It can be used as a lubricating additive in oil drilling and oil well construction to reduce equipment damage and ensure the normal operation of equipments. [ABSTRACT FROM AUTHOR]

In the present work, electrospun Kraft lignin/cellulose acetate nanostructures were produced, assessed and proposed as structuring or thickening agents of castor oil for lubricating applications. Solutions of Kraft lignins (KL) derived from different sources (eucalyptus, poplar and olive tree pruning) and cellulose acetate (CA) were prepared and used as feed for electrospinning. The rheological properties (shear and extensional viscosity), electrical conductivity and surface tension of KL/CA solutions influence the morphology of the electrospun nanofibers, which in turn is affected by the chemical structure and composition of the Kraft lignins. Electrospun KL/CA nanostructures consisting of filament-interconnected nanoparticles, beaded nanofibers or uniform nanofiber mats were able to form gel-like homogeneous fine dispersions by simply mechanically dispersing them into castor oil. The swelling of KL/CA nanofibers in the percolation network was demonstrated. The rheological, tribological and microstructural properties of these oleogels are essentially governed by the morphological characteristics of the electrospun nanostructures, i.e. fiber diameter, number of beads and porosity. Rheological properties of the resulting oleogels may be tailored by modifying the lignin source and KL:CA weight ratio. According to their rheological and tribological properties, KL/CA electrospun nanostructures-based oleogels can be proposed as a sustainable alternative to conventional lubricating greases. [ABSTRACT FROM AUTHOR]

The traditional fossil reductant used in the copper slag cleaning process cannot fulfill the requirements of sustainable development of the copper industry. Therefore, a new approach of employing waste motor oil (WMO) instead of a non-renewable fossil reductant to clean copper slag (reduce magnetite concentration and improve matte recovery) was put forward in this study. The cracking characteristics of WMO at high temperature and the effects of technical parameters (such as reduction temperature, oil amount, and settling time) on the copper loss, magnetite concentration, and WMO utilization degree were thoroughly investigated. The results indicated that the cracking products of WMO at high temperature were mainly composed of C and H2. When 1.4 mL WMO (oil/slag ratio: 0.0042) was used as reductant to clean 300 g copper slag, the utilization degree of WMO could reach more than 90 pct, the content of magnetite was reduced to less than 1 wt pct, and the content of copper in the upper level of the slag was lowered to less than 0.57 wt pct, which met the criteria for discarding slag industrially. The results provide a theoretical basis for the application of waste oil in non-ferrous metal smelting process. [ABSTRACT FROM AUTHOR]

In this research the evaluation of performance of R600a vapour compression system was investigated using CuO/Al2O3 hybrid nanolubricants. Three different hybrid nanolubricants concentrations of 0.2, 0.4 and 0.6 g/L was considered for this study with 70 g of R600a refrigerant. The experiment was conducted for the analysis of various important parameters such as coefficient of performance, refrigeration effect and compressor power consumption, pull down of refrigerator and transmittance of both mineral oil without nanoparticles and nanodoped mineral oil while using CuO/Al2O3 hybrid nanoparticles with the lubricant. The study was done with R600a refrigeration system and can be employed as better replacement for pure mineral refrigeration system. Addition of CuO/Al2O3 hybrid nanoparticles in to a compressor lubricating oil resulted in enhanced coefficient of performance up to 27% from 1.17 to 1.6 and increase in cooling capacity up to 20% from 160 to 200 W and reduction in power utilized by the compressor up to 24% from 158 to 120 W in comparison with the R600a system without nanolubricants. CuO/Al2O3 hybrid nanolubricant refrigerator can be employed as better substitute for R134a refrigerator. [ABSTRACT FROM AUTHOR]

The utilization of functional nano-additives provides us a novel research idea to deal with the in situ temperature sensing/monitoring of lubricating oil. In this work, monodispersed and luminescent calcium fluoride (CaF2) nanoparticles with surface modification were synthesized by a hydrothermal approach, which were employed as nano-additives for polyalphaolefin (PAO6) lubricating oil. Because of the surface modification of hydrophobic oleic acid molecule, the as-prepared CaF2 nanoparticles exhibited excellent oil solubility. The tribological results further suggested that after dispersing in PAO6 lubricating oil, the CaF2 nanoparticles could maintain its original friction and wear properties. In addition to the above basic characteristics for lubricating nano-additives, it was attractive to find that the as-synthesized CaF2 nanoparticles exhibited a doublet luminescence characteristic. The intensity ratio of the two emission peaks presented a nearly linear relationship to the surrounding temperature, which was also effective for CaF2 nanoparticles dispersed in PAO6 base oil. By comprehensive consideration of the oil dispersibility, tribological properties and temperature responsiveness, the as-synthesized CaF2 nanoparticles should be promising nano-additives for temperature monitoring of lubricating oil. [ABSTRACT FROM AUTHOR]

The surface quality of machining will greatly affect the service life of components. In this paper, to reduce the surface roughness and cutting force of nickel-based superalloy during machining, the milling parameters of GH4169 nickel-base superalloy under micro-lubrication conditions were optimized. Based on the response surface method, the influence of milling parameters (spindle speed, feed per tooth, micro-lubricating oil, and micro-lubricating pressure) on the surface roughness and cutting force was analysed; through the analysis of variance, the significant interaction effect and the regularity between each index were obtained, and the optimization models of surface roughness, redial, and axial cutting force were established; the multi-objective particle swarm optimization algorithm was used to optimize the model based on crowding distance sorting; the optimal combination of process parameters was determined to reduce surface roughness and achieve less cutting force. The research results show that the feed per tooth and the air pressure have the most obvious influence on the surface roughness; the interaction effect of the feed per tooth and the oil volume has the most significant influence on the radial and axial cutting forces. The radial and axial cutting forces show a trend of increasing with the increase of the feed per tooth, and decreasing with the increase of the oil amount; the optimal parameter combination was used to carry out the machining experiment, and the surface roughness and diameter. The relative error between the measured value of tangential cutting force and the predicted value of the model is 8.14%, the surface of the specimen is good, and the lowest surface roughness and cutting force are obtained, which has certain guiding significance for the successful research on the side milling of GH4169 nickel-based superalloy. [ABSTRACT FROM AUTHOR]

To lessen air pollution led by diesel exhaust emission, regeneration of soot deposited in diesel particulate filter (DPF) by catalysts has attracted great attention. It is necessary to study effects of catalysts and soluble organic fraction (SOF) on soot oxidation using thermogravimetric analysis (TGA) for improving regeneration process. The diesel soot is simulated by Printex U (PU) particles, and the SOF originates from 0# diesel fuel and 15W lubricating oil. The TGA results are evaluated by the peak temperature Tp, comprehensive combustion index S and combustion stable index Rw, respectively. Compared with ZrO2 and CeO2 catalysts, the best catalytic effect on soot oxidation is achieved when the Pt catalyst is mixed with PU at 1:1 mass ratio. With the increasing of Pt catalyst, the comprehensive combustion performance of PU becomes inferior because of heat transfer poverty. Soot oxidation performance gets degradation after adding the simulative SOF. When the mass ratio of PU/Pt/15W reaches 1:1:0.1, the comprehensive combustion performance presents the comparatively superior state. The values of S and Rw indexes of PU/Pt/15W mixture at 1:1:0.1 mass ratio reach the largest of 9.459 × 10–8%2 min−2 °C−3 and 30.85 × 105, respectively. This work investigates the soot oxidation in the presence of catalyst and SOF based on previous researches, which benefits the optimization of catalytic regeneration strategy for DPF application. [ABSTRACT FROM AUTHOR]