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An analytical formula is derived for determining the frictional coefficient at cutter–blank contact, on the basis of the cutting equations and the shear angle, and is verified by means of experimental data. This formula may be used to calculate the cutting parameters, without constraints on the significant factors.
A modern lubricant contains various additives with different functionalities and the interactions or reactions between these additives could induce synergistic or antagonistic effects in tribological performance. In this study, sum frequency generation (SFG) spectroscopy was used to investigate competitive adsorption of lubricant additives at a solid/base oil interface. A silica substrate was used as a model solid surface. The lubricant additives studied here included two oil-soluble ionic liquids (ILs, [N888H][DEHP] and [P8888][DEHP]), an antiwear additive (secondary ZDDP), an organic friction modifier (OFM), and a dispersant (PIBSI). Our results showed that for mixtures of ZDDP and IL in a base oil (PAO4), the silica surface is dominated by the IL molecules. In the cases of base oils containing OFM and IL, the silica/lubricant interface is dominated by OFM over [N888H][DEHP], while it is preferentially occupied by [P8888][DEHP] over OFM. The presence of PIBSI in the mixture of PAO4 and IL leads to the formation of a mixed surface layer at the silica surface with PIBSI as a major component. The SFG results in this investigation provide fundamental insights that are helpful to design the formulation of new lubricant additives of desired properties.
One of the first stages of planet formation is the growth of small planetesimals and their accumulation into large planetesimals and planetary embryos. This early stage occurs long before the dispersal of most of the gas from the protoplanetary disk. At this stage gas–planetesimal interactions play a key role in the dynamical evolution of single intermediate-mass planetesimals (m{sub p} ∼ 10{sup 21}–10{sup 25} g) through gas dynamical friction (GDF). A significant fraction of all solar system planetesimals (asteroids and Kuiper-belt objects) are known to be binary planetesimals (BPs). Here, we explore the effects of GDF on the evolution of BPs embedded in a gaseous disk using an N-body code with a fiducial external force accounting for GDF. We find that GDF can induce binary mergers on timescales shorter than the disk lifetime for masses above m{sub p} ≳ 10{sup 22} g at 1 au, independent of the binary initial separation and eccentricity. Such mergers can affect the structure of merger-formed planetesimals, and the GDF-induced binary inspiral can play a role in the evolution of the planetesimal disk. In addition, binaries on eccentric orbits around the star may evolve in the supersonic regime, where the torque reverses and the binary expands, which would enhance the cross section for planetesimal encounters with the binary. Highly inclined binaries with small mass ratios, evolve due to the combined effects of Kozai–Lidov (KL) cycles with GDF which lead to chaotic evolution. Prograde binaries go through semi-regular KL evolution, while retrograde binaries frequently flip their inclination and ∼50% of them are destroyed.
A wedge-shaped shock mount uses rubber for energy absorption, and the frictional characteristics of ordinary brake material for damping.
A kinetic energy absorbing device uses a series of coaxial, mating cylindrical surfaces. These surfaces have high frictional resistance to relative motion when axial impact forces are applied. The device is designed for safe deceleration of vehicles impacting on landing surfaces.
Wear and friction of mechanical carbons sliding against metal surfaces in liquid oxygen to determine their lubrication potential
Friction and wear of low melting gallium alloys on stainless steel and nickel in argon and vacuum environment
Surface emittance effect on turbulent skin friction at supersonic and low hypersonic speeds
Influence of order and order-disorder transformation on friction characteristics of copper-gold alloys in vacuum
Damping device checks the axial motion of a rotating shaft by exerting a controllable, radial frictional load to the outer race of the ball bearing in which the shaft is mounted. The device can be used as a soft bearing mount to damp resonant frequencies at critical shaft speed.
Friction loading device gives axial symmetry to test specimen of brittle materials during tensile testing. This axial alignment prevents bending stresses which hinder measurement of tensile strength.
Bearings of titanium, cobalt, and other hexagonal crystal alloys are used in vacuum and high temperature environments. These temperature-stabilized alloys have reduced friction and wear characteristics and therefore have potential use in aircraft seals, hydraulic equipment, and artificial human joints.
Test date obtained concerning the frictional pressure loss to fluids flowing in unsleeved bellows and flexible hose. This data should be useful in the design of fluid systems where high delivery velocities are involved and flexible hose or bellows must be employed.
Air bearing system supports a shaker system slip table with minimum friction. At each corner of a square of grooves made on the table, a hole is drilled through the table and fitted with air connections. Air pressure is simultaneously fed to the four fittings forming an air bearing.
Stability of frictionally heated Couette and Poiseuille flows, specifically Couette flow in inviscid limit
Friction of copper-aluminum alloys related to decreasing stacking-fault energy
Sputtered molybdenum disulfide film deposition and friction characteristics in vacuum
Heat transfer and friction resistance for carbon dioxide in supercritical region