Tribological Properties of Few-layer Graphene Oxide Sheets as Oil-Based Lubricant Additives

The performance of a lubricant largely depends on the additives it involves. However, currently used additives cause severe pollution if they are burned and exhausted. Therefore, it is necessary to develop a new generation of green additives. Graphene oxide（GO） consists of only C, H and O and thus is considered to be environmentally friendly. So the tribological properties of the few-layer GO sheet as an additive in hydrocarbon base oil are investigated systematically. It is found that, with the addition of GO sheets, both the coefficient of friction（COF） and wear are decreased and the working temperature range of the lubricant is expanded in the positive direction. Moreover, GO sheets has better performance under higher sliding speed and the optimized concentration of GO sheets is determined to be 0.5wt%. After rubbing, GO is detected on the wear scars through Raman spectroscopy. And it is believed that, during the rubbing, GO sheets adhere to the sliding surfaces, behaving like protective films and preventing the sliding surfaces from contacting with each other directly. This paper proves that the GO sheet is an effective lubricant additive, illuminates the lubrication mechanism, and provides some critical parameters for the practical application of GO sheets in lubrication.

Resveratrol alleviates oxidative stress induced by oxidized soybean oil and improves gut function via changing gut microbiota in weaned piglets

Background Oxidized soybean oil(OSO)has been shown to impair growth and exacerbate inflammation,leading to intestinal barrier injury in animals.Recent evidence suggests important roles for resveratrol(RES)in the promoting growth performance,antioxidant capacity,anti-inflammatory,and regulate intestinal barriers in animals.Therefore,The objectives of this study are to investigate the effects of dietary RES(purity 98%)supplementation on the growth performance,antioxidant capacity,inflammatory state,and intestinal function of weaned piglets challenged with OSO.Methods A total of 28 castrated weaned male piglets with a similar body weight of 10.197 replications per treatment and±0.10 kg were randomly assigned to 4 dietary treatments for 28-d feeding trial with 1 piglet per replicate.Treatments were arranged as a 2×2 factorial with oil type[3%fresh soybean oil(FSO)vs.3%OSO]and dietary RES(0vs.300 mg/kg).Results The results showed that relative to the FSO group,OSO stress tended to decrease the average daily feed intake(ADFI),and decreased the activity levels of lipase,villus/crypt ratio(VCR),the mRNA expression of FABP1,SOD2,IL-10 and ZO-1 in the jejunum,and SOD2,GPX1,occludin and ZO-1 in the colon,the levels of acetic acid in the colonic digesta,whereas up-regulated the mRNA expression of IL-1βand TNF-αin the jejunum(P<0.05).Moreover,dietary supplementation with RES increased ether extract(EE),the activity levels of sucrase,lipase,α-amylase,villus height(VH)and VCR,the mRNA expression of FABP1,SOD2,IL-10 and occludin in the jejunum,and FABP1,PPAR-γ,GPX1,occludin and ZO-1 in the colon,and the abundance of Firmicutes,acetic and propionic acid,but decreased the levels of D-lactic acid in the plasma,the abundance of Bacteroidetes in the colonic digesta of weaned piglets compared to the non-RES group(P<0.05).Meanwhile,in the interaction effect analysis,relative to the OSO group,dietary RES supplementation in the diets supplemented with OSO increased the activity levels of trypsin,VH in the jejunum,the abundance of Actinobacteria,the levels of butyric acid of weaned piglets,but failed to influence the activity levels of trypsin and VH,Actinobacteria abundance,the levels of butyric acid when diets were supplemented with FSO(interaction,P<0.05).Relative to the OSO group,dietary RES supplementation in the diets supplemented with OSO decreased the activity levels of DAO in the plasma of weaned piglets but failed to influence the activity levels of DAO when diets were supplemented with FSO(interaction,P<0.05).Relative to the FSO group,dietary RES supplementation in the diets supplemented with FSO decreased the level of propionic acid,whereas RES supplementation failed to influence the level of propionic acid when the diet was supplemented with OSO(interaction,P<0.01).Conclusions Inclusion of OSO intensified inflammatory states and impaired the intestinal health characteristics of weaned piglets.Dietary RES supplementation improved the antioxidant capacity,anti-inflammatory activity,and intestinal morphology.Further studies showed that the protective effects of RES on gut health could be linked to the decreased abundance of Prevotella_1,Clostridium_sensu_stricto_6,and Prevotellaceae_UCG003 and increased levels of acetic and propionic acid.

In situ catalytic upgrading of heavy crude oil through low-temperature oxidation

The low-temperature catalytic oxidation of heavy crude oil（Xinjiang Oilfield,China） was studied using three types of catalysts including oil-soluble,watersoluble,and dispersed catalysts.According to primary screening,oil-soluble catalysts,copper naphthenate and manganese naphthenate,are more attractive,and were selected to further investigate their catalytic performance in in situ upgrading of heavy oil.The heavy oil compositions and molecular structures were characterized by column chromatography,elemental analysis,and Fourier transform infrared spectrometry before and after reaction.An Arrhenius kinetics model was introduced to calculate the rheological activation energy of heavy oil from the viscosity-temperature characteristics.Results show that the two oil-soluble catalysts can crack part of heavy components into light components,decrease the heteroatom content,and achieve the transition of reaction mode from oxygen addition to bond scission.The calculated rheological activation energy of heavy oil from the fitted Arrhenius model is consistent with physical properties of heavy oil（oil viscosity and contents of heavy fractions）.It is found that the temperature,oil composition,and internal molecular structures are the main factors affecting its flow ability.Oil-soluble catalyst-assisted air injection or air huff-n-puff injection is a promising in situ catalytic upgrading method for improving heavy oil recovery.

Oil oxidation in the whole temperature regions during oil reservoir air injection and development methods

The oil oxidation characteristics of the whole temperature regions from 30 ℃ to 600 ℃ during oil reservoir air injection were revealed by experiments. The whole oil oxidation temperature regions were divided into four different parts: dissolving and inflation region, low temperature oxidation region, medium temperature oxidation region and high temperature oxidation region. The reaction mechanisms of different regions were explained. Based on the oil oxidation characteristics and filed tests results, light oil reservoirs air injection development methods were divided into two types: oxygen-reducing air flooding and air flooding;heavy oil reservoirs air injection in-situ combustion development methods were divided into two types: medium temperature in-situ combustion and high temperature in-situ combustion. When the reservoir temperature is lower than 120 ℃, oxygen-reducing air flooding should be used for light oil reservoir development. When the reservoir temperature is higher than 120 ℃, air flooding method should be used for light oil reservoir development. For a normal heavy oil reservoir, when the combustion front temperature is lower than 400 ℃, the development method is medium temperature in-situ combustion. For a heavy oil reservoir with high oil resin and asphalting contents, when the combustion front temperature is higher than 450 ℃, the development method at this condition is high temperature in-situ combustion. Ten years field tests of air injection carried out by PetroChina proved that air has advantages in technical, economical and gas source aspects compared with other gas agents for oilfield gas injection development. Air injection development can be used in low/super-low permeability light oil reservoirs, medium and high permeability light oil reservoirs and heavy oil reservoirs. Air is a very promising gas flooding agent.

Chronic consumption of thermally processed palm oil or canola oil modified gut microflora of rats

Dietary oils have critical influences on human health,and thermally cooking or frying modify the components and nutritional functions of oils.Palm oil was the most widely used oil in food processing industry,but its health effects remain debatable.In the current study,we aimed to compare the effects of thermally oxidized palm oil and canola oil on gut microbiota.Palm oil or canola oil were heated at 180°C for 10 h to prepare high-fat diets.Rats were fed high-fat diets for 3 months,and hematological properties,gut microflora composition and intestinal gene expression were examined.The results indicated that heated canola oil consumption elevated plasma total cholesterol and LDL-c levels compared with unheated canola oil,but heated palm oil do not had these effects;and consumption of heated palm oil significantly elevated the relative abundance of Lactobacillucs and Roseburia in gut,compared with non-heated palm oil or two canola oil groups.Moreover,intestinal expression of IL-22 was increased in heated palm oil fed animal,though ZO-1 and GPR41 were reduced.In conclusion,heating process may enhance the effects of palm oil on proliferation of probiotics Lactobacillucs,and weaken the effects of canola oil on cholesterol transport and metabolism.

Ameliorating Effect and Potential Mechanism of Camellia Oil on Constipated Mice

Constipation is a global epidemic. To evaluate the ameliorating effect of camellia oil on constipation,two slowtransit costive mice models were established by water deprivation or sucralfate gavage. Administration of camellia oil（ 4. 0 and 8. 0 mL/kg/day） significantly shortened the defecation time,increased defecation mass and fecal water content,with efficacies comparable to that of hemp seed oil. Intestinal propulsion test showed that camellia oil significantly enhanced the propelling rates of the charcoal powder in the intestine. Meanwhile,camellia oil also significantly decreased the serum levels of nitric oxide（ NO）,nitric oxide synthase（ NOS） and vasoactive intestinal peptide（ VIP） and increased serum substance P in costive animals. These results suggested that camellia oil can largely relieve slowtransit constipation and enhance the gastrointestinal motility through modulation of serum gastrointestinal motility key factors such as NO,NOS and VIP and substance P.

Oxidative desulfurization of dibenzothiophene over Fe promoted Co–Mo/Al_2O_3 and Ni–Mo/Al_2O_3 catalysts using hydrogen peroxide and formic acid as oxidants

This work reports the enhancing effect of a highly cost effective and efficient metal, Fe, incorporation to Co or Ni based Mo/Al2O3 catalysts in the oxidative desulfurization （ODS） of dibenzothiophene （DBT） using H2O2 and formic acid as oxidants. The influence of operating parameters i.e. reaction time, catalyst dose, reaction temperature and oxidant amount on oxidation process was investigated. Results revealed that 99% DBT conversion was achieved at 60℃ and 150 min reaction time over Fe-Ni-Mo/Al2O3. Fe tremendously enhanced the ODS activity of Co or Ni based Mo/Al2O3 catalysts following the activity order：Fe-Ni-Mo/Al2O3 〉 Fe-Co-Mo/Al2O3 〉 Ni-Mo/Al2O3 〉 Co-Mo/Al2O3, while H2O2 exhibited higher oxidation activity than formic acid over all catalyst systems. Insight about the surface morphology and textural properties of fresh and spent catalysts were achieved using scanning electron microscopy （SEM）, X-ray diffraction （XRD）, energy dispersive X-ray （EDX） analysis, Atomic Absorption Spectroscopy （AAS） and BET surface area analysis, which helped in the interpretation of experimental data. The present study can be deemed as an effective approach on industrial level for ODS of fuel oils crediting to its high efficiency, low process/catalyst cost, safety and mild operating condition.

Beneficial effect of refined red palm oil on lipid peroxidation and monocyte tissue factor in HCV-related liver disease： a randomized controlled study

BACKGROUND： A large amount of endotoxin can be detected in the peripheral venous blood of patients with liver cirrhosis, contributing to the pathogenesis of hepatotoxicity because of its role in oxidative stress. The present study aimed to test the effect of the supplementation with red palm oil（RPO）, which is a natural oil obtained from oil palm fruit（Elaeis guineensis） rich in natural fat-soluble tocopherols, tocotrienols and carotenoids, on lipid peroxidation and endotoxemia with plasma endotoxin-inactivating capacity, proinflammatory cytokines profile, and monocyte tissue factor in patients with chronic liver disease. METHODS： The study group consisted of sixty patients（34 males and 26 females; mean age 62 years, range 54-75） with Child A/B, genotype 1 HCV-related cirrhosis without a history of ethanol consumption, randomly enrolled into an 8-week oral daily treatment with either vitamin E or RPO. All patients had undergone an upper gastrointestinal endoscopy 8 months before, and 13 out of them showed esophageal varices.RESULTS： Both treatments significantly decreased erythrocyte malondialdehyde and urinary isoprostane output, only RPO significantly affected macrophage-colony stimulating factor and monocyte tissue factor. Liver ultrasound imaging did not show any change. CONCLUSIONS： RPO beneficially modulates oxidative stress and, not least, downregulates macrophage/monocyte inflammatory parameters. RPO can be safely advised as a valuable nutritional implementation tool in the management of chronic liver diseases.

Identification of C9-C11 unsaturated aldehydes as prediction markers of growth and feed intake for non-ruminant animals fed oxidized soybean oil

Background: The benefits of using the oxidized oils from rendering and recycling as an economic source of lipids and energy in animal feed always coexist with the concerns that diverse degradation products in these oxidized oils can negatively affect animal health and performance. Therefore, the quality markers that predict growth performance could be useful when feeding oxidized oils to non-ruminants. However, the correlations between growth performance and chemical profiles of oxidized oils have not been well examined. In this study, six thermally oxidized soybean oils(OSOs) with a wide range of quality measures were prepared under different processing temperatures and processing durations, including 45 °C-336 h;67.5 °C-168 h;90 °C-84 h;135 °C-42 h;180 °C-21 h;and225 °C-10.5 h. Broilers and nursery pigs were randomly assigned to diets containing either unheated control soybean oil or one of six OSOs. Animal performance was determined by measuring body weight gain, feed intake,and gain to feed ratio. The chemical profiles of OSOs were first evaluated by common indicative tests, including peroxide value, thiobarbituric acid reactive substances, p-anisidine value, free fatty acids, oxidized fatty acids,unsaponifiable matter, insoluble impurities, and moisture, and then analyzed by the liquid chromatography-mass spectrometry-based chemometric analysis.Results: Among common quality indicators, p-anisidine value(An V), which reflects the level of carbonyl compounds,had the greatest inverse correlation with the growth performance of both broilers and pigs, followed by free fatty acids and oxidized fatty acids. Among the 17 aldehydes identified in OSOs, C9-C11 alkenals, especially 2-decenal and 2-undecenal, had stronger inverse correlations(r <-0.8) with animal performance compared to C5-C8 saturated alkanals,suggesting that chain length and unsaturation level affect the toxicity of aldehydes.Conclusions: As the major lipid oxidation products contributing to the An V, individual C9-C11 unsaturated aldehydes in heavily-oxidized oils could function as effective prediction markers of growth and feed intake in feeding non-ruminants.

Evaluation of Selected Quality Degradation Indices for Palestinian Extra Virgin Olive Oil Bottled in Different Packaging Materials upon Storage under Different Lighting Conditions

The effect of packaging materials and lighting conditions on quality of extra virgin olive oil （EVOO） was investigated during six months. The results highlighted an influence of light and type of packaging material on EVOO-quality with storage time. At shelf, all packages maintained EVOO at the end of storage in terms of acidity, peroxide value, K232, while K270 exceeded limit of EVOO in glass and PET-stored oil. Loss of phenols was the highest in glass-stored oil and the lowest in high-density polyethylene （HDPE）-stored oil. In terms of sensory evaluation, glass-stored oil lost EVOO grade after three months and its edible compliance after six months, while HDPE-stored oil maintained EVOO grade 90 days and was virgin after six months. In extended lighting, acidity, peroxide value and K232 did not exceed EVOO grade, while K270 exceeded EVOO grade after 30 days in glass and polyethylene terephthalate （PET）-stored oil and after 90 days in HDPE. The loss of phenols was the largest in glass and smallest in HDPE-stored oil. Glass stored-oil lost organoleptic edible compliance before 90 days, while that in PET was virgin at 90 days and that in HDPE maintained EVOO quality 90 days. At the end of experiment, oils in all packages were not edible. In dark, all packages maintained oil in EVOO quality in terms of all indices. The loss of phenols was marginal but was the least in glass and the highest in HDPE. It was concluded that HDPE bottles conserve stored olive oil at shelf or illumination better than PET or glass, while in dark, glass was superior over plastic.

FTIR analysis and monitoring of used synthetic oils operated under similar driving conditions

The processes of degradation of engine oils operated in passenger cars of a uniform fleet of 25 vehicles were analyzed for oxidation content using infrared (IR) spectroscopy. As part of the experiment, the changes in engine oils occurring during actual operation (under conditions which can be described as "harsh", i.e., short distance driving, frequent starting of the engine, and extended engine idling) have been observed. An evaluation of the Fourier transform infrared spectroscopy (FTIR) spectrum of an engine oil sample was presented. The infrared spectra of both fresh and used oils were recorded with the Thermo Nicolett IS5. The tests were conducted according to the Appendix A2 of ASTM 2412. For the used engine oil differentiation process, FTIR spectra were analyzed in the regions of 1,700–2,000 cm-1 and 3,600–3,700 cm-1. The FTIR spectrometry is demonstrated to be effective for the analysis and monitoring of processes of oxidation and shown to provide rapid and accurate information relating to the aging process of engine oils. The results may facilitate decision-making regarding the service life of engine oils. The achieved dependencies can make it possible to upgrade the sensor assembly consisting of an FTIR source.

Effects of soybean isoflavone on intestinal antioxidant capacity and cytokines in young piglets fed oxidized fish oil

To investigate the effect of glycitein, a synthetic soybean isoflavone（ISF）, on the intestinal antioxidant capacity, morphology, and cytokine content in young piglets fed oxidized fish oil, 72 4-d-old male piglets were assigned to three treatments. The control group was fed a basal diet containing fresh fish oil, and the other two groups received the same diet except for the substitution with the same dosage of oxidized fish oil alone or with ISF（oxidized fish oil plus ISF）. After 21 d of feeding, supplementation of oxidized fish oil increased the levels of malondialdehyde（MDA）, oxidized glutathione（GSSG）, interleukin-1β（IL-1β）, tumor necrosis factor-α（TNF-α）, interleukin-2（IL-2）, nuclear factor κ B（NF-κB）, inducible nitric oxide synthase（iN OS）, NO, and Caspase-3 in jejunal mucosa, and decreased the villous height in duodenum and the levels of secretory immunoglobulin A（sI gA） and IL-4 in the jejunal mucosa compared with supplementation with fresh oil. The addition of oxidized fish oil plus ISF partially alleviated this negative effect. The addition of oxidized fish oil plus ISF increased the villous height and levels of sI gA and IL-4 in jejunal mucosa, but decreased the levels of IL-1β and IL-2 in jejunal mucosa（P0.05） compared with oxidized fish oil. Collectively, these results show that dietary supplementation of ISF could partly alleviate the negative effect of oxidized fish oil by improving the intestinal morphology as well as the antioxidant capacity and immune function in young piglets.

Chemical Composition,Anticancer,Anti-neuroinflammatory,and Antioxidant Activities of the Essential Oil of Patrinia scabiosaefolia

Objective：To study the chemical composition,anticancer,anti-neuroinflammatory,and antioxidant activities of the essential oil of Patrinia scabiosaefolia（EO-PS）.Methods：Patrinia scabiosaefolia was analyzed by gas chromatography-mass spectrometry.Eight human carcinoma cell lines,including SGC-7901,AGS,Hep G2,HT-29,HCT-8,5-FU/HCT-8,He La,and MDA-MB-231,were assessed by methylthiazolyldiphenyltetrazolium bromide（MTT） assay.Anti-neuroinflammatory activity was assessed by production of interleukin（IL）-1β and IL-6 induced by lipopolysaccharide in BV-2 cells（microglia from mice）.The antioxidant activity was evaluated with a 2,2-diphenyl-1-picrylhydrazyl（DPPH） scavenging assay.Results：Forty-four components,representing 83.919% of the total oil,were identified in the EO-PS.The major constituents were caryophyllene oxide（12.802%）,caryophyllene（6.909%）,α-caryophyllene（2.927%）,β-damascenone（3.435%）,calarene（5.621%）,and phenol（3.044%）.The MTT assay showed that the EO-PS exhibited significant dose-dependent growth inhibition in the 50–200 μg/m L dilution range.The EO-PS exhibited a dose-dependent scavenging activity against the DPPH radical,with an half of maximal inhibitory concentration 1.455 mg/m L.Conclusion：The EO-PS possesses a wide range of antitumor,anti-neuroinflammatory and antioxidant activities,suggesting that it may be a good candidate for further investigations of new bioactive substances.

Self-Lubricating PEO Coating on an Al Alloy Produced by Vacuum Impregnation Post-treatment

The objective of this research was to develop a novel self-lubricating coating on an AA6061 aluminum alloy.Three coatings were prepared by the plasma electrolytic oxidation（PEO） process using 50-, 500-, and 1000-Hz pulsed direct current, respectively. The as-deposited coatings were then post-treated using two different methods, viz., ultrasonic vibration-aided vacuum oil impregnation（UVOI） and oil impregnation under ambient pressure（OIAP）. After posttreatment, an oil-containing, self-lubricating top layer was formed on the coatings. The effects of the coatings＇ surface morphologies and structures on their oil-holding capabilities were discussed. The results revealed that coatings prepared with higher frequency had a greater oil-holding capacity using OIAP post-treatment, while those prepared with lower frequency had a greater oil-containing capability using UVOI post-treatment. These phenomena are related to the morphologies of the coatings produced with various current modes. The tribological properties of the coatings before and after post-treatments were investigated by pin-on-disc sliding wear tests. Due to the formation of a lubricant-containing top layer, the post-treatment coatings had a lower friction coefficient and improved wear resistance compared with the asdeposited coatings. In addition, the coatings after UVOI treatment had better wear performance than those post-treated using the OIAP process. Among all coatings, the coating produced with a 50-Hz pulsed current followed by UVOI posttreatment achieved the lowest friction coefficient（0.03） and best wear resistance when sliding against a Si3N4 ceramic counterface. This study indicates that a novel self-lubricating coating can be prepared by a PEO process combined with vacuum oil impregnation post-treatment.

Influence of oxidation of automatic transmission fluids (ATFs) and sliding distance on friction coefficients of a wet clutch in the running-in stage

In this paper,the influence of oxidation of automatic transmission fluids(ATFs)and sliding distance on the friction coefficients of a wet clutch in approached running-in conditions was investigated.The ATFs were oxidized by a laboratory process approaching oxidation occurred in actual ATFs.Oxidation was evaluated by means of increase in carbonyl compounds and depletion of zinc dialkyldithiophosphates(ZDDPs)additives.Also,the changes in kinematic viscosity and viscosity index were evaluated.Pin-ondisk tests were conducted to replicate the actual sliding contact in a wet clutch.The pin specimens were cut from friction material composite plates and the disks were actual steel separators both from an automotive wet clutch.Friction coefficient, μ,was measured at progressive sliding velocity,ν,to obtain μ–νcurves at 26 and 100°C.Three μ–νtests were consecutively run using the same pair of specimens and oil.The cumulative sliding distance for each μ–νtest generated surface flattening using the oils.The friction coefficients of the wet clutch increased due to the ATFs oxidation meanwhile the dm/dv values decreased in most cases.It suggests that ATF oxidation can enhance torque capacity of the wet clutch,but it could reduce anti-shudder property.Progressive sliding distance improved the slopes in the μ–νresults using fresh ATFs meanwhile it generated a slope decrease by using aged ATFs.