Evaluation of tribological characteristics of technical oils with fullerene compositions

2020 ◽  
Vol 98 (4) ◽  
pp. 6-12
Author(s):  
A. Kravtsov ◽  
Keyword(s):  
Experimental Studies ◽  
Fine Powder ◽  
Micelle Formation ◽  
Tribological Characteristics ◽  
Extreme Pressure ◽  
Wear Properties ◽  
High Oleic ◽  
Wear Indicator ◽  
Positive Effect ◽  
Subsequent Addition

The paper presents experimental studies of the tribological characteristics of liquid lubricants of various viscosity classes and various groups of operation when using fullerene compositions. Tribological characteristics were evaluated on a four-ball friction machine according to GOST 9490. The use of fullerene compositions in the form of a finely dispersed fullerene powder, pre-dispersed (dissolved) in vegetable high oleic oils, for example, rapeseed, with the subsequent addition of the resulting composition to technical oils of various viscosity classes and various groups of operation, leads to the following positive effect. The anti-wear properties of oils, which are assessed by the wear indicator, increase by 20,0…30,7 %, and the critical load on 18,8…25,0%. These indicators significantly exceed similar indicators when using fullerene fine powders without preliminary dispersion in vegetable oils, where the effect is on the border 11,1…15 %. Fullerene additives do not affect the extreme pressure properties of base oils, which are assessed by the scuffing load. This result makes it possible to state that the way to improve the tribological properties of lubricants by introducing a fine powder of fullerenes into base technical oils is ineffective. The experimental results obtained confirm the hypothesis about the possibility of the micelle formation mechanism in the lubricant under the action of the electrostatic field of the friction surface. The presence of a surfactant solvent (vegetable oil) allows you to "start" the micelle formation process at lower fullerene concentrations and to obtain the effect of increasing anti-wear properties.

scholarly journals Evaluation of tribological characteristics of liquid lubricants with fullerene additives

2020 ◽  
Vol 97 (3) ◽  
pp. 50-54
Author(s):  
A. Kravcov ◽  
Keyword(s):  
Wear Rate ◽  
Critical Load ◽  
Experimental Studies ◽  
Tribological Characteristics ◽  
Wear Properties ◽  
Liquid Lubricant ◽  
Fullerene Concentration ◽  
Technological Methods ◽  
Positive Effect ◽  
Finely Dispersed Powder

The paper presents experimental studies of the tribological characteristics of liquid lubricants of various viscosity classes and various groups of operation when using fullerene additives. Tribological characteristics were evaluated on a four-ball friction machine according to GOST 9490. Assessment was subject to: wear rate and critical load, which characterize the anti-wear properties of the lubricant, as well as welding load and bully index, which characterize an anti-bully properties of the material. It is shown that the improvement of the wear index for all oils begins with the concentration 0,2 % masses, fullerenes in the lubricant and does not exceed the values 11,1 … 15 %. At a fullerene concentration less than 0,2 % masses, no positive effect is observed. Positive effect 11,8 … 17,4 % characteristic of the indicator – critical load that characterizes the range of performance of anti-wear additives. At the same time, an increase in the critical load begins with concentration 0,1 % masses, fullerenes in a lubricant and manifests itself most effectively at a concentration 0,2 % masses. Changes in the magnitude of the welding load during the experiments were not recorded, this allows us to conclude, that the addition of a finely dispersed fullerene powder in a liquid lubricant does not improve anti-bully properties, but is only an anti-wear additive. It is shown that the way to improve the tribological properties of lubricants by introducing a finely dispersed powder of fullerenes in base technical oils is ineffective. It is necessary to develop other, more technological methods and methods for introducing fullerene additives into technical lubricants.

scholarly journals Implementation Intentions to Reduce Smoking: A Systematic Review of the Literature

2020 ◽  
Author(s):  
Charlotte J Hagerman ◽  
Rebecca K Hoffman ◽  
Sruthi Vaylay ◽  
Tonya Dodge
Keyword(s):  
Systematic Review ◽  
Implementation Intentions ◽  
Experimental Studies ◽  
Implementation Intention ◽  
Promising Tool ◽  
Current Systematic Review ◽  
Long Term Follow Up ◽  
Positive Effect

Abstract Implementation intentions are a goal-setting technique in which an individual commits to perform a particular behavior when a specific context arises. Recently, researchers have begun studying how implementation intention (II) interventions can facilitate antismoking efforts. The current systematic review synthesized results of experimental studies that tested the effect of an II intervention on smoking cognitions and behavior. Of 29 reviewed articles, 11 studies met inclusion criteria. Nine studies (81.8%) tested an II intervention as a cessation tool for current smokers, whereas two tested II interventions as a tool to prevent smoking among predominantly nonsmoking adolescents. A majority of the studies (66.7%) testing II interventions as a cessation tool reported a positive effect on cessation at long-term follow-up. Of the two studies testing II interventions as a tool for prevention, one study found a positive effect on long-term follow-up. Methodology varied between the studies, highlighting the discrepancies between what researchers consider “implementation intentions” to be. II interventions are a promising tool for antismoking efforts, but more research is necessary to determine the best methodology and the populations for whom this intervention will be most effective. Implications Brief, free, and easily scalable, II interventions to prevent smoking are highly attractive for antismoking efforts. This review outlines the circumstances under which II interventions have demonstrated effectiveness in helping people resist smoking cigarettes. We illuminate gaps in the existing literature, limitations, methodological discrepancies between studies, and areas for future study.

Study of the Impact of Protective Process Agents with Carbon Nanopowder Additives on Chip Forming Processes

2021 ◽  
Vol 887 ◽  
pp. 319-324
Author(s):  
E.A. Petrovsky ◽  
K.A. Bashmur ◽  
Vadim S. Tynchenko
Keyword(s):  
Experimental Studies ◽  
Cutting Speed ◽  
Optimal Composition ◽  
Cooling Process ◽  
Shrinkage Ratio ◽  
Nickel Chromium ◽  
Chromium Alloys ◽  
On Chip ◽  
The Impact ◽  
Positive Effect

The present study describes the impact of various protective process agents on chip forming processes. The research was conducted on NiCr20TiAl and 34NiCrMoV14-5 nickel-chromium alloys. New lubricant-cooling process agents with carbon nanopowder additives are studied. The optimal composition of the nanopowder additive and its effect during alloy cutting is examined. Experiments reveal the dependence of shrinkage ratio on cutting speed and various protective process agents. The values of H50 microhardness are also defined when cutting these alloys using protective process agents. Experimental studies found the positive effect of developed agents with nanopowder additives on the processes of NiCr20TiAl and 34NiCrMoV14-5 alloys chip formation.

scholarly journals Do You Get the Picture? A Meta-Analysis of the Effect of Graphics on Reading Comprehension

AERA Open ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 233285842090169 ◽  
Author(s):  
Daibao Guo ◽  
Shuai Zhang ◽  
Katherine Landau Wright ◽  
Erin M. McTigue
Keyword(s):  
Reading Comprehension ◽  
Grade Level ◽  
Text Comprehension ◽  
Meta Analysis ◽  
Experimental Studies ◽  
Future Research ◽  
Significant Difference ◽  
Flow Diagrams ◽  
Positive Effect ◽  
Mixed Format

Although convergent research demonstrates that well-designed graphics can facilitate readers’ understanding of text, there are select situations where graphics have been shown to have no effect on learners’ overall text comprehension. Therefore, the current meta-analytic study examined 39 experimental studies published between 1985 and 2018 measuring graphics’ effects on readers’ comprehension. We first quantified the overall effect on reading comprehension. Then, we considered interactions with learners’ characteristics, graphic types, and assessment formats. Our analysis revealed that the inclusion of graphics had a moderate overall positive effect (Hedges’s g = 0.39) on students’ reading comprehension, regardless of grade level. Regarding graphic type, we did not find a significant difference among pictures, pictorial diagrams, and flow diagrams. Only when compared to mixed graphics, pictures had a greater effect on comprehension. Additionally, compared with true and false assessments, graphics differentially benefited students’ comprehension on open-ended comprehension assessments and mixed format assessments. Implications for future research are presented.

Friction and Wear Properties of Laser Cladding Coatings under Boundary Lubrication Conditions

2011 ◽  
Vol 314-316 ◽  
pp. 143-146
Author(s):  
Xin Feng ◽  
Yan Qiu Xia
Keyword(s):  
Phase Composition ◽  
Laser Cladding ◽  
Friction And Wear ◽  
Liquid Paraffin ◽  
Extreme Pressure ◽  
Wear Properties ◽  
Aisi 52100 ◽  
Aisi 1045 ◽  
Aisi 52100 Steel ◽  
Friction And Wear Properties

AISI 1045 steels were laser-clad with Ni-based powder by CO2 HJ-4 coherent laser. The phase composition of the laser-cladding coating was investigated by means of X-ray diffraction (XRD). The cross-section of the cladding coating was observed using a scanning electron microscopy (SEM). The friction and wear properties of the laser cladding coatings sliding against AISI 52100 steel under the lubrication of liquid paraffin containing various anti-wear and extreme pressure additives were investigated using an Optimol SRV reciprocating motion friction and wear tester. Results showed that the laser-cladding coating considerably decreased coefficient of friction and increased wear resistance in sliding against AISI 52100 steel and attributed to the change in the hardness, phase composition of the laser-cladding coating and tribochemical reactions between the laser-cladding coating and the extreme pressure and anti-wear additives.

Effect of hexagonal boron nitride nanoparticles as an additive on the extreme pressure properties of engine oil

2016 ◽  
Vol 68 (4) ◽  
pp. 441-445 ◽  
Author(s):  
Muhammad Ilman Hakimi Chua Abdullah ◽  
Mohd Fadzli Bin Abdollah ◽  
Noreffendy Tamaldin ◽  
Hilmi Amiruddin ◽  
Nur Rashid Mat Nuri
Keyword(s):  
Diesel Engine ◽  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
Experimental Studies ◽  
Engine Oil ◽  
Lubricating Oil ◽  
Extreme Pressure ◽  
Content Type ◽  
Load Carrying ◽  
Sonication Technique

Purpose This paper aims to investigate the effect of hexagonal boron nitride (hBN) nanoparticles on extreme pressure (EP) properties when used as an additive in lubricating oil. Design/methodology/approach The nano-oil was prepared by dispersing an optimal composition of 0.5 vol. per cent of 70 nm hBN in SAE 15W-40 diesel engine oil using a sonication technique. The tribological testing was performed using a four-ball tribometer according to the ASTM standard. Findings It was found that the nano-oil has a potential to decelerate the seizure point on the contact surfaces, where higher EP can be obtained. More adhesive wear was observed on the worn surfaces of ball bearing lubricated with SAE 15W-40 diesel engine oil as compared with the nano-oil lubrication. Originality/value The results of the experimental studies demonstrated the potential of hBN as an additive for improving the load-carrying ability of lubricating oil.

The Effects of Using Colored Paper to Boost Response-Rates to Surveys and Questionnaires

2003 ◽  
Vol 33 (1) ◽  
pp. 29-40 ◽  
Author(s):  
James Hartley ◽  
Andrew Rutherford
Keyword(s):  
Surveys And Questionnaires ◽  
Meta Analysis ◽  
Experimental Studies ◽  
Response Rates ◽  
Colored Paper ◽  
Positive Effect

Many people have speculated over the last 80 years or so about the possibilities of using colored paper to boost response-rates to surveys and questionnaires, and several studies have been carried out. Most of these enquiries report no significant effects from using colored paper, although there have been some exceptions. In this investigation we pooled together the results from all of the experimental studies known to us on the topic and we carried out a meta-analysis to see if there might be a positive effect for colored paper overall. The results indicated that this was not the case, for we found no significant differences between the response rates to white and to colored paper in general. However, when we considered separately the most common colors used, it appeared that pink paper had the greatest effect.

BPNN-QSTR Models for Triazine Derivatives for Lubricant Additives

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Tingting Wang ◽  
Zhan Wang ◽  
Hao Chen ◽  
Kang Dai ◽  
Xinlei Gao
Keyword(s):  
Tribological Properties ◽  
Back Propagation ◽  
Three Dimensional ◽  
Predictive Ability ◽  
Quantitative Relationship ◽  
Molecular Structures ◽  
Lubricant Additives ◽  
Extreme Pressure ◽  
Wear Properties ◽  
Triazine Derivatives

Abstract Triazine derivatives are a kind of lubricant additives with excellent tribological properties. It is of great significance to study the quantitative relationship between their chemical structure and tribological properties. In the present study, the quantitative structure tribo-ability relationships (QSTR) between 20 triazine derivatives and their respective extreme-pressure properties as lubricant additives were analyzed by the back propagation neural network (BPNN) method. The BPNN-QSTR model had satisfactory stability and predictive ability (R2 = 0.9965, R2(LOO) = 0.9195, q2 = 0.8274). The anti-wear model also yielded good predictions (R2 = 0.9757, R2(LOO) = 0.6261, q2 = 0.8022). Two- and three-dimensional structural descriptors were used to analyze molecular structures that affected extreme-pressure and anti-wear properties. The results indicate that the three-dimensional molecular dimensions and the bonding modes of the skeleton atoms in the molecules were important factors. In addition, the effects of N, P, O, and other hetero-atoms on the tribological properties were reflected in their corresponding group types and electronic structures.

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