نتایج جستجو برای: low friction
تعداد نتایج: 1231107 فیلتر نتایج به سال:
The amplitude-dependent internal friction due to dislocations oscillating in the lattice is described in terms of dislocation mobility. This kind of intemal friction is expressed in elementary forms in the two limiting cases, i.e. at hish and low frequencies, and with the results obtained, the behavior of relaxation peaks due to dislocations are discussed 1 INTRODUCTION The amplitude-dependent ...
In the analysis of orthogonal cutting process using finite element (FE) simulations, predictions are greatly influenced by two major factors; a) flow stress characteristics of work material at cutting regimes and b) friction characteristics mainly at the tool-chip interface. The uncertainty of work material flow stress upon FE simulations may be low when there is a constitutive model for work m...
The dynamics and the transition to the centrifugal regime are studied analytically and numerically for particles in rotating drum. The importance of the particle-wall friction coefficient is demonstrated by studying first the motion of one non-rotating particle where three different regimes are found in the transition to the centrifugal motion. When a few rotating particles are considered, they...
A kind of 2.5-dimensional C/C-SiC composites was fabricated by using Isothermal Chemical Vapour Infiltration process (ICVI). Frictional properties of this material were evaluated by using MM-1000 under dry condition. Average dynamic friction coefficient of it was 0.16, static friction coefficient and average coefficient stability were 0.15 and 0.56, respectively. However, weight wear rate was l...
Few measurements have been made of the frictional forces within living joints. Barnett and Cobbold (1962) recorded that the coefficient of friction at the distal interphalangeal joint of the middle finger in six healthy adults could be as low as 0 0075, a figure of the same order as that in excised joints (Jones, 1936; Charnley, 1959). Rydell (1965) measured, in a patient fitted with a hip pros...
The friction and wear properties of graphene and graphene oxide (GO) with varying C/O ratio were investigated using friction force microscopy. When applied as solid lubricants between a sliding contact of a silicon (Si) tip and a SiO2/Si substrate, graphene and ultrathin GO films (as thin as 1-2 atomic layers) were found to reduce friction by ∼6 times and ∼2 times respectively as compared to th...
We study the friction between a flat solid surface where polymer chains have been end-grafted and a cross-linked elastomer at low sliding velocity. The contribution of isolated grafted chains’ penetration in the sliding elastomer has been early identified as a weakly velocity dependent pull-out force. Recent experiments have shown that the interactions between the grafted chains at high graftin...
We study the friction of a poly(dimethylsiloxane) (PDMS) rubber network sliding, at low velocity, on a substrate on which PDMS chains are end-tethered. We thus clearly evidence the contribution to friction of the pullout mechanism of chain ends that penetrate into the network. This interfacial dissipative process is systematically investigated by probing the velocity dependence of the friction ...
We conducted experiments in which steel and silicon or quartz are clamped together. Even with the smallest tangential forces we could apply, we always found reproducible sliding motions on the nanometer scale. The velocities we study are thousands of times smaller than in previous investigations. The samples first slide and then lock up even when external forces hold steady. One might call the ...
We investigated the subdomain structures of single-layer graphene oxide (GO) by characterizing local friction and conductance using conductive atomic force microscopy. Friction and conductance mapping showed that a single-layer GO flake has subdomains several tens to a few hundreds of nanometers in lateral size. The GO subdomains exhibited low friction (high conductance) in the sp(2)-rich phase...
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