Silicone oil as a corneal lubricant to reduce corneal edema and improve visualization during

AIM:To evaluate the efficacy and safety of silicone oil(SO)as a corneal lubricant to improve visualization during vitrectomy.METHODS:Patients who underwent vitreoretinal surgery were divided into two groups.Group 1 was operated on with initial SO(Oxane 5700)as a corneal lubricant.Group 2 was operated on with initial lactated ringer’s solution(LRS)and then replaced with SO as required.Fundus clarity was scored during the surgery.Fluorescein staining was performed to determine the damage to corneal epithelium.RESULTS:Totally 114 eyes of 114 patients were included.Single SO use maintained a clear cornea and provided excellent visualization of surgical image.In group 1,the fundus clarity was grade 3 in 41/45 eyes and grade 2 in 4/45 eyes.In group 2,corneal edema frequently occurred after initial LRS use.The fundus clarity was grade 3 in 19/69 eyes,2 in 37/69 eyes and 1 in 13/69 eyes(P<0.05).SO was applied in 29 eyes of initial LRS use with subsequent corneal edema,which eliminated the corneal edema in 26 eyes.Corneal fluorescein staining score in group 1 was 0 in 28 eyes,1 in 11 eyes and 2 in 6 eyes,and 40,20 and 9,respectively,in group 2(all P>0.05).CONCLUSION:The use of SO as a corneal lubricant is effective and safe for preserving and improving corneal clarity and providing clear surgical field during vitrectomy.

Biomimetic lubricant-grafted surfaces on laser-textured microwell arrays with multifunctionality

Recently,various slippery liquid-infused porous surfaces(SLIPS)have been fabricated for the protection of various materials.However,these SLIPSs are limited by their underlying storage structure and superficial lubricant layer,showing poor durability.Herein,inspired by the high-strength structure of Shell nacre’s“brick-mud”layer,we fabricated an all-inorganic composite coating by using wet chemically etched MXene as a brick and an aluminum phosphate binder(AP)as mud.Then,a series of microwell-array structures were designed and prepared on the coating via nanosecond ultrafast laser writing ablation technology.Subsequently,the textured surface was modified by a silane coupling agent.Vinyl-terminated polydimethylsiloxane(PDMS)was tightly grafted onto the porous surface through a thiol-ene click reaction to obtain lubricant grafted texture surface(LGTS).The prepared LGTS showed good lubrication properties for multiple phases,including various liquids,ice crystals,and solids.It exhibits excellent chemical stability and mechanical durability under deionized water impact,centrifugal test,strong acid solutions,anti/de-icing cycles,and high-intensity friction.Thus,the proposed strategy for constructing robust LGTS will greatly promote theoretical research on super wetting interfacial materials and their applications in the fields of antifouling,anti/de-icing,and lubricating protection.

Attribute-driven Fuzzy Fault Tree Model for Adaptive Lubricant Failure Diagnosis

Lubricant diagnosis serves as a crucial accordance for condition-based maintenance(CBM)involving oil changing and wear examination of critical parts in equipment.However,the accuracy of traditional end-to-end diagnosis models is often limited by the inconsistency and random fluctuations in multiple monitoring indicators.To address this,an attribute-driven adaptive diagnosis method is developed,involving three attributes:physicochemical,contamination,and wear.Correspondingly,a fuzzy fault tree(termed FFT)-based model is constructed containing the logic correlations from monitoring indicators to attributes and to lubricant failures.In particular,inference rules are integrated to mitigate conflicts arising from the reverse degradation of multiple indicators.With this model,the lubricant conditions can be accurately assessed through rule-based reasoning.Furthermore,to enhance its intelligence,the model is dynamically optimized with lubricant analysis knowledge and monitoring data.For verification,the developed model is tested with lubricant samples from both the fatigue experiment and actual aero-engines.Fatigue experiments reveal that the proposed model can improve the lubricant diagnosis accuracy from 73.4%to 92.6%compared with the existing methods.While for the engine lubricant test,a high accuracy of 90%was achieved.

Vegetable Oil-Based Nanolubricants in Machining:From Physicochemical Properties to Application

Cutting fluid is crucial in ensuring surface quality and machining accuracy during machining.However,traditional mineral oil-based cutting fluids no longer meet modern machining’s health and environmental protection require-ments.As a renewable,pollution-free alternative with excellent processing characteristics,vegetable oil has become an inevitable replacement.However,vegetable oil lacks oxidation stability,extreme pressure,and antiwear proper-ties,which are essential for machining requirements.The physicochemical characteristics of vegetable oils and the improved methods’application mechanism are not fully understood.This study aims to investigate the effects of viscosity,surface tension,and molecular structure of vegetable oil on cooling and lubricating properties.The mechanisms of autoxidation and high-temperature oxidation based on the molecular structure of vegetable oil are also discussed.The study further investigates the application mechanism and performance of chemical modification and antioxidant additives.The study shows that the propionic ester of methyl hydroxy-oleate obtained by epoxidation has an initial oxidation temperature of 175℃.The application mechanism and extreme pressure performance of conventional extreme pressure additives and nanoparticle additives were also investigated to solve the problem of insufficient oxidation resistance and extreme pressure performance of nanobiological lubricants.Finally,the study discusses the future prospects of vegetable oil for chemical modification and nanoparticle addition.The study provides theoretical guidance and technical support for the industrial application and scientific research of vegetable oil in the field of lubrication and cooling.It is expected to promote sustainable development in the manufacturing industry.

Grindability Evaluation of Ultrasonic Assisted Grinding of Silicon Nitride Ceramic Using Minimum Quantity Lubrication Based SiO_(2)Nanofluid

Minimum quantity Lubrication(MQL)is a sustainable lubrication system that is famous in many machining systems.It involve the spray of an infinitesimal amount of mist-like lubricants during machining processes.The MQL system is affirmed to exhibit an excellent machining performance,and it is highly economical.The nanofluids are understood to exhibit excellent lubricity and heat evacuation capability,compared to pure oil-based MQL system.Studies have shown that the surface quality and amount of energy expended in the grinding operations can be reduced considerably due to the positive effect of these nanofluids.This work presents an experimental study on the tribological performance of SiO_(2)nanofluid during grinding of Si_(3)N_(4)ceramic.The effect different grinding modes and lubrication systems during the grinding operation was also analyzed.Different concentrations of the SiO_(2)nanofluid was manufactured using canola,corn and sunflower oils.The quantitative evaluation of the grinding process was done based on the amount of grinding forces,specific grinding energy,frictional coefficient,and surface integrity.It was found that the canola oil exhibits optimal lubrication performance compared to corn oil,sunflower oil,and traditional lubrication systems.Additionally,the introduction of ultrasonic vibrations with the SiO_(2)nanofluid in MQL system was found to reduce the specific grinding energy,normal grinding forces,tangential grinding forces,and surface roughness by 65%,57%,65%,and 18%respectively.Finally,regression analysis was used to obtain an optimum parameter combinations.The observations from this work will aid the smooth transition towards ecofriendly and sustainable machining of engineering ceramics.

Molecular Mechanism and Molecular Design of Lubricating Oil Antioxidants

To overcome the limitations of traditional experimental“trial and error”methods in lubricant additive design,a new molecular design method based on molecular structure parameters is established here.The molecular mechanism of the antioxidant reaction of hindered phenol,diphenylamine,and alkyl sulfide are studied via molecular simulations.Calculation results show that the strong electron-donating ability and high hydrogen-donating activity of the antioxidant molecule and the low hydrogen-abstracting activity of free radicals formed after dehydrogenation are the internal molecular causes of the shielding of phenol and diphenylamine from scavenging peroxy free radicals,and the strong electron-donating ability is the internal molecular cause of the high activity of thioether in decomposing alkyl hydrogen peroxide.Based on this antioxidant molecular mechanism,a molecular design rule of antioxidant is proposed,namely“high EHOMO,large Q(S),low bond dissociation energy BDE(O—H)and BDE(N—H)”.Two new antioxidants,PAS-I and PAS-II,are designed and prepared by chemical bonding of hindered phenol,diphenylamine,and sulfur atoms.Experimental results show that these antioxidants both have excellent antioxidant effects in lubricating oil,and that PAS-II is the superior antioxidant,consistent with theoretical predictions.

Multifunctional Lubricant Additive Improves Lubrication and Antioxidation Properties of Tung Oil

It is of considerable significance to develop efficient and environmentally friendly machinery lubricant additives because of the increasing depletion of petrochemical resources and severe environmental problems.Herein,we proposed a facile strategy to synthesize a multifunctional vegetable oil-based lubricant via the lignin derivative vanillin coupled to amine and diethyl phosphite to produce a lubricating additive with both extreme pressure and antioxidant properties.Compared with pure tung oil,the lubricating and antioxidant performance of tung oil is significantly improved after adding additives.Adding the 1.0 wt%additive to the tung oil reduced the friction wear coefficient and the volume,and the oxidation induction time was much longer than pure tung oil.

Next Generation Lubricants and Their Potential Use in Fertility Treatment

While generally recognized as a potential source of contamination during the collection process, lubricants are often used at the preference of the male partner to prevent irritation. While older lubricants have been studied, there is currently no conscience within programs as to what constitutes a “safe” lubricant. The object of the current study was designed to evaluate chemically unique “next generation” lubricants in comparison to lubricants currently in use in fertility treatment and/or recognized as fertility safe;the first was a silicone-based lubricant, the second is a water-based, plant-based organic compound, in comparison to two established medical lubricants and a control. Twelve deidentified semen samples from the clinical andrology laboratory were used to test the lubricants following semen analysis. In order to enter the study, the sample had to have a minimum of 30 × 106 motile cells. Samples were then processed using a simple sperm wash modified to reconstitute the pellet into a final volume of 7 mL. Half-milliliter aliquots were then transferred into 13 wells of a standard 24-well culture plate. One well was used as a control. The remaining wells received one of the four lubricants at one of three volumes (10, 50, or 100 uL), producing 12 treatment combinations (four lubricants + 3 concentration levels) and the control. The samples were then cultured at room temperature for 24 hours. At times 0, 1, 3, 12, and 24 hrs, the plate was agitated to remix the sample, and a 4 uL aliquot of each well was analyzed for standard semen parameters using a computer-assisted semen analyzer. Results indicated the expected decrease in semen parameters over time in all treatments (P < 0.001). There was also a dose-dependent drop in most of the lubricants. However, samples contaminated with the newer lubricants appeared to maintain semen parameters similar to the controls at all but the 100 ul level of contamination, while the older lubricants caused decreases in sperm function at much lower concentrations. While semen parameters alone should not be the only criteria for the selection of a lubricant, the present study suggests newer formulations of lubricant are less likely to interfere with sperm function.

Synthesis and mechanism of environmentally friendly high temperature and high salt resistant lubricants

With the exploration and development of deep and ultra-deep oil and gas,high torque and high friction during the drilling of deep and ultra-deep wells become one of the key issues affecting drilling safety and drilling speed.Meanwhile,the high temperature and high salt problem in deep formations is prominent,which poses a major challenge to the lubricity of drilling fluids under high temperature and high salt.This paper reports an organic borate ester SOP as an environmentally friendly drilling fluid lubricant.The performance evaluation results show that when 1%lubricant SOP is added to the fresh water-based mud,the lubrication coefficient decreases from 0.631 to 0.046,and the reduction rate of lubrication coefficient is 92.7%.Under the conditions of 210℃ and 30%NaCl,the reduction rate of lubricating coefficient of the base slurry with 1%SOP was still remain 81.5%.After adding 1%SOP,the wear volume decreased by 94.11%compared with the base slurry.The contact resistance experiment during the friction process shows that SOP can form a thick adsorption film on the friction surface under high temperature and high salt conditions,thus effectively reducing the friction resistance.Molecular dynamics simulation shows that lubricant SOP can be physically adsorbed on the surface of drilling tool and borehole wall through hydrogen bond and van der Waals force.XPS analysis further shows that SOP adsorbs on the friction surface and reacts with metal atoms on the friction surface to form a chemically reactive film.Therefore,under high temperature and high salt conditions,the synergistic effect of physical adsorption film and chemical reaction film effectively reduces the frictional resistance and wear of the friction surface.In addition,SOP is non-toxic and easy to degrade.Therefore,SOP is a highly effective and environmentally friendly lubricant in high temperature and high salt drilling fluid.

Excellent lubricating hydrogels with rapid photothermal sterilization for medical catheters coating

Bacterial infection and tissue damage caused by friction are two major threats to patients’health in medical catheter implantation.Hydrogels with antibacterial and lubrication effects are competitive candidates for catheter coating materials.Photothermal therapy(PTT)is a highly efficient bactericidal method.Here,a composite hydrogel containing MXene nanosheets and hydrophilic 3-sulfopropyl methacrylate potassium salt(SPMK)is reported,which is synthesized through the one-pot method and heat-initiated polymerization.The hydrogel shows excellent antibacterial performance against Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)in 3 min in the air or 20 min in the water environment under near-infrared light(NIR;808 nm)irradiation.The friction coefficient of the hydrogel is about 0.11,which is 48%lower than that without SPMK.The rapid photothermal sterilization is attributed to the outstanding antibacterial ability and thermal effect of photoactivated MXene.The ultra-low friction is the result of the hydration lubrication mechanism.This study provides a potential strategy for the surface coatings of biomedical catheters,which enables rapid sterilization and extremely low interface resistance between catheters and biological tissues.

A“bricks-and-mortar”structured graphene oxide/polyvinyl alcohol coating:Enhanced water interfacial lubrication and durability

Coatings serve as ideal protective films for mechanical systems,providing dependable as well as efficient lubrication because of their unique structure along with outstanding tribological characteristics.Inspired by the“bricks-and-mortar”structure,we prepared layered graphene oxide(GO)composite finishes strengthened with polyvinyl alcohol(PVA)and borax.Our study demonstrates that the tribological properties of the GO-based coating on 304 stainless steel(SS304)are potentially greatly affected through PVA,GO,and annealing.By optimizing the composition,we achieved the PVA_(40 wt%)/GO_(0.01 wt%)/borax composite coating,which exhibited the lowest average coefficient of friction(COF)of 0.021±0.003(a 97.86%reduction compared to control SS304)with minimal wear and abrasion even in a water environment.We found that the enhanced mechanical characteristics as well as elastic recovery within the coating were attributed to the hydrogen bonds and cross-linking between PVA and borax,which led to stress distribution.Reduced friction was further aided by the formation of a hydrated layer at the friction interface.As a result,the coating demonstrated remarkable durability,maintaining a low COF during long sliding distances(576 m,28,800 cycles,significantly longer than previously reported)without breaking.

Fluorographene with Narrow Lateral Size and Thickness Distributions Prepared for Enhancing Lubrication Performance of Bentonite Grease

Fluorographene(FG)with narrow lateral size and thickness distributions was prepared by a liquid-phase exfoliation method,based on liquid cascade centrifugation.The Rtec MFT-5000 tribo-meter was used to investigate the lubricating performance of bentonite grease enhanced by the as-prepared FG.The results showed that the coefficient of friction and the wear volume of bentonite grease with 0.3 wt%FG were decreased by 20.4%and 44.9%,respectively,as compared to those of the base grease.The main reason is that FG can promote the formation of the tribo-chemical reaction film consisting of complex carbon oxide,Fe_(2)O_(3)and FeF_(3)on the friction surface,which can remarkably improve the performance of friction reduction and prevent the appearance of severe wear.

Lubrication antagonism mechanism of nano-MoS_(2)and soot particles in ester base oil

Spherical nano-MoS_(2)(S-MoS_(2))has excellent lubricating properties and potential application value in engine oil additives.Engine soot can enter the engine oil,so the tribological interaction between S-MoS_(2)and diesel combustion soot(DCS)should be investigated.In this study,DCS was used to simulate engine soot.The interaction was investigated in dioctyl sebacate(DOS),and the interaction mechanism was full characterized.Results showed that S-MoS_(2)and DCS had obvious antagonism effects on lubrication.The 0.5%S-MoS_(2)exhibited good lubricating properties in DOS,which could reduce friction by~22%and wear by~54%.However,after 0.5%S-MoS_(2)was added to the 0.5%DCS contaminated DOS,the lubrication performance was not improved and was even worse than that without S-MoS_(2).When S-MoS_(2)was added for DOS lubrication,a tribofilm containing MoS_(2)formed on the friction surface,but simultaneously adding 0.5%DCS resulted in the disappearance of the MoS_(2)tribofilm.Moreover,under the action of friction heat,DCS and S-MoS_(2)could form hard Mo_(x)C_(y),thereby increasing abrasive wear.Finally,a preliminary deantagonism method was provided.After 2.0%zinc isooctyl dithiophosphate was added to the above antagonistic system,the friction coefficient did not show visible changes,but the wear recovered to a level close to that when only S-MoS_(2)was added.The antiantagonism method is not very satisfactory and some more efficient methods need to be further explored.

FlowBreakdown of Hybrid Nanofluid on a Rigid Surface with Power Law Fluid as Lubricated Layers

Thiswork investigates an oblique stagnation point flowof hybrid nanofluid over a rigid surface with power lawfluidas lubricated layers. Copper (Cu) and Silver (Ag) solid particles are used as hybrid particles acting in water H2O asa base fluid. The mathematical formulation of flow configuration is presented in terms of differential systemthat isnonlinear in nature. The thermal aspects of the flow field are also investigated by assuming the surface is a heatedsurface with a constant temperature T. Numerical solutions to the governing mathematical model are calculatedby the RK45 algorithm. The results based on the numerical solution against various flow and thermal controllingparameters are presented in terms of line graphs. The specific results depict that the heat flux increases over thelubricated-indexed parameter.

Design and optimization of fluid lubricated bearings operated with extreme working performances——a comprehensive review

Fluid lubricated bearings have been widely adopted as support components for high-end equipment in metrology,semiconductor devices,aviation,strategic defense,ultraprecision manufacturing,medical treatment,and power generation.In all these applications,the equipment must deliver extreme working performances such as ultraprecise movement,ultrahigh rotation speed,ultraheavy bearing loads,ultrahigh environmental temperatures,strong radiation resistance,and high vacuum operation,which have challenged the design and optimization of reliable fluid lubricated bearings.Breakthrough of any related bottlenecks will promote the development course of high-end equipment.To promote the advancement of high-end equipment,this paper reviews the design and optimization of fluid lubricated bearings operated at typical extreme working performances,targeting the realization of extreme working performances,current challenges and solutions,underlying deficiencies,and promising developmental directions.This paper can guide the selection of suitable fluid lubricated bearings and optimize their structures to meet their required working performances.

Identification of Lubricating Oil Additives Using XGBoost and Ant Colony Optimization Algorithms

To address the problem of identifying multiple types of additives in lubricating oil,a method based on midinfrared spectral band selection using the eXtreme Gradient Boosting(XGBoost)algorithm combined with the ant colony optimization(ACO)algorithm is proposed.The XGBoost algorithm was used to train and test three additives,T534(alkyl diphenylamine),T308(isooctyl acid thiophospholipid octadecylamine),and T306(trimethylphenol phosphate),separately,in order to screen for the optimal combination of spectral bands for each additive.The ACO algorithm was used to optimize the parameters of the XGBoost algorithm to improve the identification accuracy.During this process,the support vector machine(SVM)and hybrid bat algorithms(HBA)were included as a comparison,generating four models:ACO-XGBoost,ACO-SVM,HBA-XGboost,and HBA-SVM.The results showed that all four models could identify the three additives efficiently,with the ACO-XGBoost model achieving 100%recognition of all three additives.In addition,the generalizability of the ACO-XGBoost model was further demonstrated by predicting a lubricating oil containing the three additives prepared in our laboratory and a collected sample of commercial oil currently in use。

Thermal oxidation of two aviation synthetic lubricant base oils

The thermal degradation of two synthetic lubricants base oils, poly-a-olefins （PAO） and di-esters （DE）, was investigated under oxidative pyrolysis condition and their properties were characterized in simulated ＂areo-engine＂ by comparing the thermal stability and identifying the products of thermal decomposition as a function of exposure temperature. The characterization of the products were performed by means of Fourier transform infrared spectrometry （FTIR）, gas chromatography/mass spectrometry （GC/MS） and viscosity experiments. The results show that PAO has the lower thermal stability, being degraded at 200℃ different from 300 ℃ for DE. Several by-products are identified during the thermal degradation of two lubricant base oils. The majority of PAO products consist of alkenes and olefins, while more oxygen-contained organic compounds are detected in DE samples based on GC/MS analysis. The related reaction mechanisms are discussed based on the experimental results.

EVALUATION OF LUBRICANTS FOR COLD ROLLING ALUMINUM STRIPS

Various kinds of base oils were applied to cold rolling aluminum strips on a test mill for evaluationof the influences of these base oils,aromatics contents and viscosity of base oils on their lubricating performances and surface reflectivity of rolled strips at annealing. Results showed that low friction coefficient androlling force were obtained by using the normal paraffins,whereas their contaminations on the annealed stripsurface were the same as those of other saturated hydrocarbons. Aromatics in base oil affected the stir face reflectivity of annealed strips, but the decrease of aromatics in base oil was ineffective to improve rolled stripssurface quality when it is less than 1 %. Base oil viscosity has the great influences on the lubricating performances and surface reflectivity of annealed strips just in this condition.

SWOT-AHP hybrid model for vehicle lubricants from CNPCLC,China

In recent years, owing to the strong increase in demand for lubricants, China is ranked second in the global lubricant market. With the rapid development of China＇s automobile industry, there is an increasing demand for vehicle lubricants and an increasing requirement for higher quality lubricants. While the demands for vehicle lubricants are increasing year by year in China, the quality grade of vehicle lubricant will be improved by leaps and bounds, and the high standard lubricant for automobile will be directly brought in line with international practice. At present, the market share of most high-end vehicle lubricant has been occupied by foreign lubricant brands. So for China National Petroleum Corporation Lubricant Company （CNPCLC）, the urgent issue is that strategies must be made to respond to the stern challenges and to occupy more market share. In this paper, by using the analytic hierarchy process （AHP） technique that has the advantage of combining quantitative with qualitative analysis, a SWOT-AHP model for CNPCLC vehicle lubricants is developed, presenting a good tool for studying the competitive factors domestic and overseas for vehicle lubricants. Finally a strategic plan for CNPCLC vehicle lubricants is suggested.

Low-cost solid FeS lubricant as a possible alternative to MoS2 for producing Fe-based friction materials

Three reaction systems of MoS_2-Fe, FeS -Fe, and Fe S-Fe-Mo were designed to investigate the use of FeS as an alternative to MoS_2 for producing Fe-based friction materials. Samples were prepared by powder metallurgy, and their phase compositions, microstructures, mechanical properties, and friction performance were characterized. The results showed that MoS_2 reacts with the matrix to produce iron-sulfides and Mo when sintered at 1050°C. Iron-sulfides produced in the MoS_2-Fe system were distributed uniformly and continuously in the matrix, leading to optimal mechanical properties and the lowest coefficient of friction among the systems studied. The lubricity observed was hypothesized to originate from the iron-sulfides produced. The Fe S-Fe-Mo system showed a phase composition, porosity, and density similar to those of the MoS_2-Fe system, but an uneven distribution of iron-sulfides and Mo in this system resulted in less-optimal mechanical properties. Finally, the Fe S-Fe system showed the poorest mechanical properties among the systems studied because of the lack of Mo reinforcement. In friction tests, the formation of a sulfide layer contributed to a decrease in coefficient of friction（COF） in all of the samples.