scholarly journals Operational characteristics of new biological lubricants

2021 ◽  
pp. 201-211
Author(s):  
A.Yu. Popovskii ◽  
B.A. Altoiz ◽  
A.F. Butenko ◽  
A.K. Kopeyka ◽  
Laurencas Raslavicius
Keyword(s):  
Friction Pair ◽  
Structural Characteristics ◽  
Static Friction ◽  
Viscosity Coefficient ◽  
Optical Measurements ◽  
Operational Characteristics ◽  
Friction Regime ◽  
Main Component ◽  
Friction Surfaces ◽  
Equilibrium Thickness

The lubricating characteristics of ultrathin interlayers of bio-oil RMO made from coastal algae P.Moriformis are investigated in this work. One of the most important qualities of the oil is its lubricity of the friction surfaces. It determines the possibility of formation of a stable separating film between contact surfaces, with orientational ordering in wall adjacent layers, with the strength value required in the boundary friction regime. The structural characteristics of such epitropic-liquid crystal (ELC) layers are essential when choosing a lubricant. Static friction pair was studied by the optical method of admixtured absorption dichroism. It was found that the value of the order parameter of ELC layer and its equilibrium thickness are much higher in compare with the layers of aliphatic hydrocarbons, which are the basis of modern mineral lubricants. The rheological characteristics of ultrathin interlayers were studied in a dynamic triad of friction. Processing of the effective viscosity coefficient dependence on the shear rate, interlayer thickness and temperature allowed us to estimate the value of equilibrium thickness of the ELC layer, which coincides with the results of optical measurements. The marked structural peculiarities of the ELC in the biooil interlayers are conditioned with the formation of molecular associates of oleic acid, which is the main component of studied oil.

INFLUENCE OF THE DYNAMICS OF FORCED MOTION ON THE STATIC FRICTION IN METAL-POLYMER SLIDING PAIRS

Tribologia ◽  
2021 ◽  
Vol 295 (1) ◽  
pp. 21-26
Author(s):  
Mariusz Opałka ◽  
Wojciech Wieleba ◽  
Angelika Radzińska
Keyword(s):  
Relative Motion ◽  
Friction Pair ◽  
Polymeric Materials ◽  
Static Friction ◽  
Metallic Materials ◽  
Test Results ◽  
Friction Resistance ◽  
Rate Of Increase ◽  
Polymer Metal ◽  
Metal Polymer

The resistance during the frictional interaction of polymeric materials with metallic materials is characterized by a significant dependence on the dynamics of the motion inputs. In a metal-polymer friction pair, the static friction resistance during standstill under load depends on the rate of growth of the force causing the relative motion. Tribological tests of selected (polymer-metal) sliding pairs were carried out. The selected polymers were polyurethane (TPU), polysulfone (PSU), and silicone rubber (SI). They interacted with a pin made of normalized C45 steel under unitary pressure p = 0.5 MPa in dry friction conditions at different gradients of the force driving the relative motion (dF/dt = 0.1-20 [N/s]). The static friction coefficient of the selected sliding pairs was determined on the basis of the recorded static friction force values. The test results show a significant influence of the rate of increase in the motion driving force on the values of static friction resistance. This is mainly due to the viscoelastic properties of polymers.

Research of the kinetics of thickness of the boundary layers of lubricating materials applied to drilling technology

2021 ◽  
pp. 115-120
Author(s):  
R.A. Ismakov ◽  
◽  
V.G. Konesev ◽  
F.N. Yangirov ◽  
G.L. Gaymaletdinova ◽  
...  
Keyword(s):  
Service Life ◽  
Boundary Layers ◽  
Friction Pair ◽  
Roller Bearing ◽  
Equipment Safety ◽  
Efficiency And Effectiveness ◽  
Drilling Technology ◽  
Resource Characteristics ◽  
Friction Surfaces ◽  
Kinetics Of

Improving the operational properties of lubricants increases the service life of the mechanisms and increase the durability of rubbing joints, which has a positive effect on the indicators of technical and economic efficiency and equipment safety. Therefore, great attention in tribology is paid to the analysis of the state of friction units in technology and the assessment of their resource characteristics, which makes it possible to increase their service life. The research aim is to study the general provisions on lubricants and lubricants, as well as the features of the boundary layers formation on friction surfaces and the observed patterns. Calculations of the boundary layers thickness using lubricating reagents at different energetic loading of the friction pair were carried out as applied to the roller bearing of a roller cone bit in the medium of cylinder oil 52 and DPS grease. The proposed research methodology made it possible to in-crease the efficiency and effectiveness of the means development for improving the tribotech-nical properties of drilling lubricants.

scholarly journals Technology to Increase Hydrocarbon Wear Resistance of Friction Units of Hydrogen Aggregates

2019 ◽  
Vol 297 ◽  
pp. 09001 ◽  
Author(s):  
Mikhail Shalygin ◽  
Sergei Kuznetsov
Keyword(s):  
Wear Resistance ◽  
Steel Surface ◽  
Friction Pair ◽  
Dehydration Process ◽  
Diffusion Capacity ◽  
Friction Units ◽  
Surface Irregularities ◽  
Friction Surfaces ◽  
Technological Methods ◽  
Wear Tests

The causes of hydrogen wear of the friction surfaces involved in hydrocarbon transfer and distillation processes are considered. Some technological methods for reducing the hydrogen wear of parts and friction units operating in hydrocarbon environment are given. A comprehensive technology for obtaining the properties of the surface layer is proposed, which provides an increase in the wear resistance of a friction pair and smoothing the surface roughness. The increase in wear resistance is based on several mechanisms: (1) decreasing biographical hydrogen due to the dehydration process; (2) smoothing surface irregularities by saturating the surface with silicon; (3) reducing the diffusion capacity of the steel surface caused by diffusion siliconizing; (4) reducing grain size of the material. Comparative wear tests were carried out, which showed the effectiveness of the proposed methods.

Power Loss of Slipper within Axial Piston Pump

2015 ◽  
Vol 779 ◽  
pp. 3-12
Author(s):  
Ze Bo Wang ◽  
Ji Hai Jiang ◽  
Yi Sun
Keyword(s):  
Power Loss ◽  
Friction Pair ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Factors Affecting ◽  
Friction Power ◽  
Swash Plate ◽  
Model Of Friction ◽  
Friction Surfaces ◽  
Axial Piston

The pair between slipper and swash-plate is an important friction pair in the axial piston pump. Due to quick relative velocity, alternating load, numerous slippers, and high contact pressure between the friction surfaces, the wear-out and fatigue failure constantly occurs, which is one of the key factors affecting reliability of the piston pump. It is of fundamental significance to investigate the mechanism of slipper power loss and to find an appropriate method to improve the lubrication of the slipper. Here, the model of friction power loss between slipper and swash-plate is established, and the friction power loss between slipper and swash-plate is solved and comparatively analysed. Finally, the correctness of theoretical analysis and simulation results are verified by experiments.

scholarly journals Massive, ancient sea-ice strata and preserved physical-structural characteristics in the Ward Hunt Ice Shelf

1991 ◽  
Vol 15 ◽  
pp. 125-131 ◽  
Author(s):  
Martin O. Jeffries
Keyword(s):  
Sea Ice ◽  
Structural Characteristics ◽  
Ice Core ◽  
Gravity Drainage ◽  
Physical Processes ◽  
Ice Shelf ◽  
The West ◽  
Time Intervals ◽  
Long Time ◽  
Equilibrium Thickness

Two sea-ice layers, one measured as 9 m thick, the other at least 12 m thick and estimated to be 24.5 m thick, have been located by ice core drilling in the west Ward Hunt Ice Shelf. To examine the preservation of physical-structural characteristics over long time intervals, the crystal structure and brine volumes in the sea ice, which possibly dates back to about 3000 BP, have been studied. The structural characteristics are immediately recognizable as those of undeformed congelation sea ice accreted by Stefan growth. Brine volumes in the ancient sea ice are higher than those in modern multi-year ice at the same temperature. The preservation of brine over a time span of hundreds to thousands of years is attributed to an absence of surface meltwater to effect brine flushing and the very slow, even negligible action of gravity drainage, brine pocket migration and brine expulsion. The congelation structures indicate that sea ice can grow by the Stefan accretion mechanism to thicknesses exceeding the equilibrium thickness (2.5–5 m) of most undeformed multi-year ice. The observed physical-structural characteristics of the Ward Hunt sea ice strongly suggest that many of the properties attained by sea ice are permanent and not affected by slow-acting physical processes.

scholarly journals Aroma Profile of Star Anise and the Structure-odor Relationship of Anethole

2014 ◽  
Vol 9 (2) ◽  
pp. 1934578X1400900 ◽  
Author(s):  
Toshio Hasegawa ◽  
Haruna Seimiya ◽  
Takashi Fujihara ◽  
Noriko Fujiwara ◽  
Hideo Yamada
Keyword(s):  
Hydrogen Atom ◽  
Methoxy Group ◽  
Structural Characteristics ◽  
Structural Features ◽  
Aroma Profile ◽  
Methyl Group ◽  
Star Anise ◽  
Main Component ◽  
Relationship Of ◽  
Methyl Benzene

Star anise is an important fragrance material that has a characteristic anise-like odor. Although the main component of star anise is ( E)-anethole, which accounts for over 90% of the constituents, the odor of ( E)-anethole is different from that of the material itself. Here, we examined the aroma profile of star anise. GC-MS analysis of star anise extracts showed that it contains many compounds with structures similar to ( E)-anethole. Our results indicate that ( E)-anethole is the key compound in the odor of star anise, but structurally similar compounds play an important role in creating its odor. We examined the structure-odor relationship of ( E)-anethole, focusing on the methoxy and 1-propenyl substituents. Altering the 1-propenyl group changed the odors of all the anethole derivatives. Replacing the methoxy group with a hydrogen atom created compounds with similar fatty odors. This shows that the methoxy group is important for the characteristic odor of anethole. We synthesized anethole derivatives where the methoxy group was replaced with a methyl group. In both methoxy- and methyl-substituted anethole derivatives, altering the 1-propenyl group changed the odors of the derivatives. Therefore, the methoxy and methyl benzene moieties are important structural features for the odor of star anise. The structural characteristics of anethole are closely related to its odor expression.

INFLUENCE OF SURFACE LASER TEXTURING ON FRICTION AND WEAR OF PTFE DURING SLIDING AGAINST STEEL

Tribologia ◽  
2018 ◽  
Vol 281 (5) ◽  
pp. 27-31
Author(s):  
Piotr KOWALEWSKI ◽  
Tomasz GAŁEK
Keyword(s):  
Microscopic Observation ◽  
Friction And Wear ◽  
Static Friction ◽  
Linear Wear ◽  
Apparent Effect ◽  
Laser Texturing ◽  
Friction Coefficients ◽  
Plate Test ◽  
Surface Laser ◽  
Friction Surfaces

The paper presents research and analysis of PTFE wear during cooperation with steel. The surface of steel elements was subjected to laser texture. Three different patterns of texture were applied to the surface of steel elements. For comparative purposes, an element without a structure was also tested. The experiment was carried out in a roller-plate test on the author’s research stand. As part of the conducted tests, the linear wear of PTFE plates was determined, and the values of the kinetic and static friction coefficients of the tested friction pairs were determined. Steel friction surfaces were also subjected to SEM microscopic observation. The obtained results showed an apparent effect of laser texture on changes in friction and wear of PTFE. This influence is different and depends on the pattern of the texture.

Wear Problems of Slide-Friction Pair

2015 ◽  
Vol 220-221 ◽  
pp. 361-366
Author(s):  
Guntis Springis ◽  
Janis Rudzitis ◽  
Anita Avišāne ◽  
Maris Kumermanis ◽  
Jevgenijs Semjonovs ◽  
...  
Keyword(s):  
Service Life ◽  
Sliding Friction ◽  
Friction Pair ◽  
Calculation Model ◽  
Surface Geometry ◽  
Wear Process ◽  
Layer Material ◽  
Wear Calculation ◽  
Form Deviation ◽  
Friction Surfaces

A number of different mechanisms and devices may involve sliding-friction surfaces. The issues of service life and its prediction for the details of such surfaces have always been of particular importance. The article determines the most suitable wear calculation model that allows considering the set of parameters necessary for calculating slide-friction pair. The offered model is based on the application of the theories of several branches of sciences. Since the wear process is variable and many-sided, it is influenced by numerous different parameters, for example, surface geometry (roughness, waviness, form deviation, etc.), physical and mechanical conditions of the upper layer, material components, wear regime, wear temperature, etc.

scholarly journals Determination of physical, mechanical, and structural seed properties of pepper cultivars

2015 ◽  
Vol 29 (1) ◽  
pp. 107-113 ◽  
Author(s):  
Ilknur Alibas ◽  
Nezihe Koksal
Keyword(s):  
Stainless Steel ◽  
Aspect Ratio ◽  
Moisture Content ◽  
Structural Characteristics ◽  
Initial Moisture Content ◽  
Static Friction ◽  
Friction Angle ◽  
Terminal Velocity

Abstract The aim of the present study was to determine various physical, mechanical, and structural characteristics of seed of pepper cultivars Yağlık Kapya, Demre Sivri, Yalova Carliston, Kandil Dolma, and Cin Sus Yediveren, which are grown extensively in Turkey, with initial moisture content ranging between 7.03 and 7.21% (w.b.). Width, length, and thickness were found to be in the range of 3.00-3.72, 3.43-4.40, and 0.66-0.82 mm, respectively. It was revealed that sphericity of the seeds of Yağlık Kapya, Demre Sivri, Yalova Carliston, Kandil Dolma, and Cin Sus Yediveren were 51, 57, 56, 51 and 57%, respectively. In terms of the roundness which ranges between 76 and 85% depending on pepper cultivars. The aspect ratio of Yağlık Kapya, Demre Sivri, Yalova Carliston, Kandil Dolma, and Cin Sus Yediveren were determined to be 84.60, 88.04, 94.43, 85.55, and 87.67%, respectively. It was also noted that the porosity of the pepper seeds was in the range of 44.94-49.61%. Besides, we found that as the weight of pepper seeds increased, their terminal velocity increased accordingly, and thus terminal velocities were found to be 2.87-4.66 m s-1. In the current study, the static friction angle and coefficients of the cultivars were determined by means of six different plates including aluminium, stainless steel, galvanized iron, rubber, glass, and plywood. The plywood plate was found to be the least slippery; consequently, the static friction angle and coefficient were determined to be the highest for the plywood plate.

scholarly journals Studies of mezozooplankton in the Zmiinyi Island coastal waters in 2016-2017

2019 ◽  
Keyword(s):  
Coastal Waters ◽  
Structural Characteristics ◽  
Taxonomic Composition ◽  
The State ◽  
The Black Sea ◽  
Environment Quality ◽  
Pelagic Larvae ◽  
Species Dynamics ◽  
Main Component ◽  
Sea Fish

Purpose. To study the state of mezozooplankton in the Zmiinyi Island coastal waters in 2016-2017. Methods. Standard methods of mezozooplankton sampling, determination, number and biomass assessment. Results. Based on the data received, analysis of biodiversity and structural characteristics of mezozooplankton in the Zmiinyi Island coastal waters has been made. Taxonomic composition, number and biomass have been determined for each species; dynamics of number and biomass presented season by season. Marine environment quality assessment has been performed on the metrics of mezozooplankton. Conclusions. Altogether 32 taxa of 9 main mezozooplankton groups were identified in 2016-2017. It was shown that the dominating groups were Copepoda, Rotatoria, Protozoa, Cladocera and Harpacticoida. Shannon’s biodiversity index of mezozooplankton varied from 0.41 (20.06.2016) to 3.29 (24.07.2016) with average values 2.32 in 2016 and 1.64 in 2017. Mezozooplankton number and biomass varied in 2016-2017 within broad limits from 645 to 55829 ind/m³ and 1.385 to 2597.248 mg/m³ respectively (with average values 10129 ind/m³ and 154.82 mg/m³ in the period IV-XII, 2016 and 21563 ind/m³ and 466.30 mg/m³ in the period IV-VI, 2017). Water quality in the coastal waters of the Zmiinyi Island on the state of mezozooplankton was «Bad» in 18 cases out of 68 (26.4%) and was assessed in general as «Poor». On total mezozooplankton biomass the state was assessed as «Poor» and «Bad» (68.2%). «Good» (10.6%) and «High» (9.1%) quality was found in 19.7% of cases, which evidenced unsatisfactory state of mezozooplankton – the main component of food reserve for pelagic larvae and pelagic species of the Black Sea fish.

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