Experimental Study on Powder Suppression Characteristics of Autoclaved Brick

2013 ◽  
Vol 773 ◽  
pp. 272-277
Author(s):  
Wei Zhang ◽  
Yan Yan Zhang ◽  
Fan Zhu
Keyword(s):  
Experimental Study ◽  
Coefficient Of Friction ◽  
Lateral Pressure ◽  
Powder Compaction ◽  
Compression Rate ◽  
The Coefficient Of Friction ◽  
Pressing Technology

The curves of cylinder displacement and pressure can be obtained through the wall brick press autoclaved brick experiment, which can determine the powder compaction equation, including suppression, friction and the characteristics of stripping, modify Kawakita equation, and improve the calculation precision, get the product of the coefficient of friction and lateral pressure and its variation law with compression rate; .in order to provide the basis for the design of pressure machine and mould and optimization of pressing technology

Skin-skin contact: The normal-force dependence of the coefficient of friction between a bare finger and artificial skin changes randomly

2021 ◽  
Author(s):  
Koki Inoue ◽  
Shogo Okamoto ◽  
Yasuhiro Akiyama ◽  
Yoji Yamada
Keyword(s):  
Experimental Study ◽  
Coefficient Of Friction ◽  
Normal Force ◽  
Skin Surface ◽  
Artificial Skin ◽  
Skin Changes ◽  
Root Cause ◽  
Skin Contact ◽  
The Coefficient Of Friction ◽  
Frictional Forces

Abstract This study investigates the dependence of the coefficients of friction on the normal force produced by sliding a bare finger over different artificial skins with seven levels of hardness. The coefficient of friction was modeled as a power function of the normal force. An experimental study that involved sliding a finger over artificial skin surfaces was carried out under two conditions: the fingertip being wiped by a dry cloth or a cloth soaked in ethanol. Although the exponential term was assumed to be nearly constant for identical tribological conditions, we observed that the exponent varied randomly and could be negative, zero, or positive. This probabilistic behavior has not been explicitly analyzed in previous studies on human fingertips. The probability density function of the exponent depended on the moisture content of the finger. The exponent was either nearly zero or positive when the finger sliding on the skin surface was wiped with an alcohol-soaked cloth and dried. These findings play an important role in analyzing the frictional forces produced during skin–skin contact in terms of determining the root cause behind the random variations in the dependence of the coefficient of friction on the normal force.

Determination of Tire-Road Friction Coefficients for Skid Mark Analysis

1985 ◽  
Vol 13 (1) ◽  
pp. 41-64
Author(s):  
W. R. Garrott ◽  
D. A. Guenther
Keyword(s):  
Experimental Study ◽  
Coefficient Of Friction ◽  
Friction Coefficients ◽  
Pickup Truck ◽  
The Road ◽  
Heavy Trucks ◽  
Road Friction ◽  
Brake Application ◽  
The Coefficient Of Friction

Abstract An experimental study was made to compare the validities of methods currently used by accident reconstructionists to determine the coefficient of friction between the road and the vehicle tires at the time of an incident. This value could then be used in conjunction with skid mark length and vehicle weight to calculate the prebraking speed of the vehicle. Three automobiles and three trucks with a variety of tires and loadings were used on a variety of pavements. The accuracy and area of applicability of each of four methods for obtaining friction coefficients were determined by relating the prebraking speed calculated from each to the actual speed at the time of brake application. All four methods were satisfactory for automobiles and the pickup truck used, but only two were acceptable for heavy trucks. The most valid coefficients are obtained from skid mark lengths obtained under conditions duplicating those in an incident.

Experimental Study on Superlubricity of Ag Nanometer-Thick Layers by Sliding on a Macroscopic System

2005 ◽  
Author(s):  
Minoru Goto ◽  
F. Honda ◽  
T. Nakahara
Keyword(s):  
Experimental Study ◽  
Coefficient Of Friction ◽  
Network Structure ◽  
Scale Up ◽  
Film Morphology ◽  
Macroscopic System ◽  
The Coefficient Of Friction ◽  
Thick Layers ◽  
Plate Type ◽  
Ag Film

The experimental study on the Ag film was carried out using a diamond pin-on-plate type tribometer under ultrahigh vacuum (UHV) conditions. The coefficient of friction varied with the film morphology in nanometric scale up to 170 nm, and superlubricity as minimum coefficient of friction 0.007 was obtained on 5-nm Ag film with network structure. RHEED and STM observation of the film showed that the film morphologies changed drastically during rubbing, and that the superlubricity of this system is attributed to the lamella gliding of Ag (111) sheets.

Paper 4: An Experimental Study of the Frictional Behaviour of Steels at Elevated Temperatures

1966 ◽  
Vol 181 (15) ◽  
pp. 1-10
Author(s):  
L. A. Mitchell ◽  
T. S. Crawford
Keyword(s):  
Experimental Study ◽  
Coefficient Of Friction ◽  
Elevated Temperatures ◽  
Oxide Films ◽  
Hardened Steel ◽  
Material Combination ◽  
Severe Wear ◽  
Mild Wear ◽  
The Coefficient Of Friction ◽  
Frictional Behaviour

Many investigators, by the manner of presentation of results, have implied that for any given material combination and atmosphere, the coefficient of friction is a function of temperature alone. Experiments are described which were designed to evaluate the importance of the sliding and temperature histories on the unlubricated sliding performance of steels at temperatures up to 500°C. Only for a hardened steel, when mild wear prevailed, was the specimen history unimportant, and, in this case, μ was virtually independent of temperature. With materials exhibiting severe wear, sliding produced changes in friction which were attributed to hardening of the surfaces and when the thickness of oxide films became comparable with the size of transferred particles, exposure to temperature could modify subsequent frictional behaviour.

Experimental Investigation of Porous Bronze Bearings

1973 ◽  
Vol 95 (2) ◽  
pp. 173-179 ◽  
Author(s):  
C. Cusano ◽  
R. M. Phelan
Keyword(s):  
Experimental Study ◽  
Experimental Investigation ◽  
Coefficient Of Friction ◽  
Boundary Lubrication ◽  
Operating Conditions ◽  
The Coefficient Of Friction ◽  
Theoretical Analyses ◽  
Lubrication Conditions

An experimental study was made of the performance of porous bronze bearings under different operating conditions. A PV value of 50,000 psi ft/min was found to be too high for the assembly used when the bearings were lubricated only by the oil initially provided within their structure. Tests at a PV value of 33,000 psi ft/min gave satisfactory results. The coefficient of friction was found to vary with load and to be almost independent of speed for the bearings tested under boundary lubrication conditions. Except for relatively light loads and moderate and higher speeds, the bearings operate under boundary lubrication conditions. When pressurized oil was supplied to the bearings, it was found that, for the same operating conditions, porous bearings run at higher eccentricity ratios than solid bearings, as predicted by theoretical analyses.

scholarly journals The Effect of Annealing Temperatures on Selected Properties of WC/C Coatings, Deposited Using Hexacarbonyl Wolfram in an N2-SiH4 Atmosphere

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4658
Author(s):  
Peter Horňák ◽  
Daniel Kottfer ◽  
Karol Kyzioł ◽  
Marianna Trebuňová ◽  
Mária Kaňuchová ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Chemical Vapor Deposition ◽  
Chemical Composition ◽  
Coefficient Of Friction ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Protective Atmosphere ◽  
Annealing Temperatures ◽  
The Coefficient Of Friction

In this paper, we present the results of an experimental study on WC/C coatings, deposited by using plasma-enhanced chemical vapor deposition in an N2-SiH4 atmosphere, annealed at temperatures of 200, 500 and 800 °C, in which the hexacarbonyl of W was used as a precursor. During the experiments, the topography, chemical composition, morphology, as well as selected mechanical properties, such as hardness, Young’s modulus, and coefficient of friction of the WC/C coatings were analyzed. Annealing without the protective atmosphere in the mentioned temperatures caused a decrease in hardness (up to 15 ± 2.7 GPa). In addition, the coefficient of friction value increased only to 0.37 ± 0.03.

Experimental study on the coefficient of friction of the ball screw

2021 ◽  
pp. 1-18
Author(s):  
Lu-Chao Zhang ◽  
Chang-Guang Zhou
Keyword(s):  
Experimental Study ◽  
Coefficient Of Friction ◽  
Hydrodynamic Lubrication ◽  
Friction Torque ◽  
Measuring System ◽  
Ball Screw ◽  
Stribeck Curve ◽  
Key Factor ◽  
The Coefficient Of Friction ◽  
Curve Fitting Method

Abstract The coefficient of friction (COF) is a key factor to estimate the performance of ball screws. Pieces of research focus on the experimental study of the COF, leading to the COF chosen empirically in many studies. To acquire the COF of the HJG-4010, a measuring system is conducted to detect the friction torque under different preloads and rotational speeds and the effects of the applied axial load and rotational speed on the COF are analyzed. By the curve fitting method, the Stribeck curve of the ball screw is obtained. The experimental results show that the lubricating state can be divided into two categories: the mixed lubrication state, and the hydrodynamic lubrication state. This study is beneficial to choose a suitable working condition for a different performance of the ball screw.

scholarly journals An Experimental Study on Starved Grease Lubricated Contacts

Lubricants ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 82 ◽  
Author(s):  
David Gonçalves ◽  
Armando Campos ◽  
Jorge Seabra
Keyword(s):  
Experimental Study ◽  
Film Thickness ◽  
Coefficient Of Friction ◽  
Contact Area ◽  
Operating Conditions ◽  
Thickness Profile ◽  
Lubricated Contacts ◽  
The Coefficient Of Friction ◽  
Over Time ◽  
Ball On Disc

The film thickness of a ball-on-disc contact lubricated with four greases of different formulations was measured under different operating conditions until starvation. Two polymer-thickened greases and two lithium-thickened greases, formulated with base oils of different nature and/or viscosity, were tested. The central film thickness was measured under constant operating conditions (load, temperature, slide-to-roll ratio) varying only the entrainment speed. In a separate test, the film thickness was measured over time with all operating conditions set to constant. Pictures of the film thickness profile across the contact area were also registered. The results were compared with the fully flooded results. The coefficient of friction (COF) was measured in a ball-on-disc contact under equal operating conditions and the results were correlated with the film thickness findings. The different grease formulations and the influence of the operating conditions on the film thickness and COF were discussed. The polymer thickened the greases, promoting lower COF and higher film thickness, especially when there is thickener material crossing the contact which happens quite often for these greases.

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