Nanostructured lubricant additives for titanium alloy:Lubrication by the solid-liquid interface with Coulomb repulsion

In this work,the advantage of Coulomb repulsion in the intermolecular forces experienced by molecules on the solid–liquid nanosized contact interface is taken,and the superior friction-reducing property of Cu_(3)(PO_(4))2·3H_(2)O(CuP)oil-based additives has been confirmed for titanium alloy.Three-dimensional(3D)CuP nanoflowers(CuP-Fs)with a strong capillary absorption effect are prepared to achieve the homogeneous mixing of solid CuP and lubricating oil.Lubrication by CuP-Fs additives for titanium alloy,friction coefficient(COF)can be reduced by 73.68%,and wear rate(WR)reduced by 99.69%.It is demonstrated that the extraordinary friction-reducing property is due to the repulsive solid–liquid interface with low viscous shear force originating from Coulomb repulsion between polar water molecules in CuP and non-polar oil molecules.However,any steric hindrance or connection between this repulsive solid–liquid interface will trigger the adhesion and increase the viscous shear force,for example,dispersant,hydrogen bondings,and shaky adsorbed water molecules.Besides,the lamellar thickness of CuP and the molecular size of lubricant both have a great influence on tribological properties.Here the lubrication mechanism based on interface Coulomb repulsion is proposed that may help broaden the scope of the exploration in low-friction nanomaterial design and new lubricant systems.

Microencapsulated Lactobacillus plantarum promotes intestinal development through gut colonization of layer chicks

The effects of Lactobacillus plantarum in microencapsulation(LPM)on intestinal development in layer chicks were investigated in this study,as well as the colonization of L.plantarum in the gut.A total of 480 healthy Hy-Line Brown layer chicks at 0 d old were randomly divided into 4 groups(8 replicates each treatment),and the diets of these birds were supplemented with nothing(control),L.plantarum(0.02 g/kg feed;10^(9) CFU/kg feed),LPM(1.0 g/kg feed;109 CFU/kg feed)and wall material of LPM(WM;0.98 g/kg feed),respectively.Compared to control,LPM improved growth performance and intestinal development of layer chicks,evidenced by significantly increased body weight,average daily gain,average daily feed intake,villus height,villus height/crypt depth,as well as weight and length of the duodenum,jejunum and ileum(P<0.05).These results could be attributed to the increased colonization of L.plantarum in the gut,which was verified by significant increases in lactic acid content,viable counts in chyme and mucosa(P<0.05),as well as a visible rise in number of strains labeled with fluorescein isothiocyanate.Meanwhile,the relative abundances of Lactobacillus and Bifidobacterium significantly increased in response to microencapsulated L.plantarum supplementation(P<0.05),accompanied by the significant up-regulation of colonization related genes(P<0.05),encoding solute carrier family,monocarboxylate transporter,activin A receptor,succinate receptor and secretogranin II.To sum up,microencapsulated L.plantarum supplementation promoted intestinal development,which could be attributed to the enhancement of L.plantarum colonization in the intestine through the mutual assistance of Bifidobacterium and interactions with colonization related transmembrane proteins.

Nanomaterials for lubricating oil application:A review

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.

Motor oil condition evaluation based on on-board diagnostic system

The condition of the motor oil in civilian cars is difficult to monitor;hence,we propose a method to evaluate the degree of degradation of motor oil using an on‐board diagnostic(OBD)system.Three civilian cars and four motor oils(containing mineral oils and synthetic oils)were subjected to five groups of road tests under urban traffic and high‐way conditions.The operation information,oil service time,mileage,engine operation time,idle time of the engine,and number of start‐ups of the engine were obtained using the proposed OBD system.Physiochemical properties and changes in the components of motor oils during road tests were analyzed in laboratory.The theoretical model of the comprehensive indicators of driving parameters and oil properties were established.The proposed method was successfully applied to different cars,motor oils,and operating conditions in road tests.All the theoretical models had high accuracy and precision.Herein,we provide a method to monitor the oil condition with real‐time driving parameters and provide a reference for end users to change their motor oil reasonably.

Motor oil degradation during urban cycle road tests

Several civilian vehicles in China operate in urban traffic conditions and have their motor oil changed every 5,000 km.This study investigates the variations in oil properties after servicing at 5,000 km,based on systematic road tests(including a repeated test,a parallel test,and a new vehicle test).The physicochemical properties,changes in components,oxidation stability,detergent‐dispersant performance,and tribological properties of motor oils were analyzed.The results showed that the total acid number(TAN)of oils increased with the operation mileage,by up to 1.41 mgKOH/g.The total base number(TBN)decreased after the road tests were completed,and the decrease was less than 44.6%.The kinematic viscosity(KV)of most oils decreased initially and then stabilized in the middle stage,before starting to increase later in the experiment.The change in KV at 100℃was less than 15.96%.The oxidation onset temperature(OOT)of the oils diminished gradually with the operation mileage.All OOT values of the used oils were higher than 210℃.A spot test indicated that the used oils retained their detergentdispersant performance to an appropriate extent.The four‐ball wear scar diameters and friction coefficient of the used oils did not increase significantly after the road tests were completed.This study can serve as a reference for end‐users when changing motor oils.