A threaded tubular connection for drilling or operating hydrocarbon wells contains a portion of a tubular element with a male end having an axis of revolution and provided with a first threading extending about the axis of revolution, the male end portion being complementary with a portion of a tubular element with a female end having an axis of revolution and provided with a second threading extending about the axis of revolution, the male and female end portions being capable of being connected by makeup, each of the male and female end portions further comprising a sealing surface with a metal-metal interference, wherein the threading and the sealing surfaces of the male and female end portions are coated with a metallic anti-corrosion and anti-galling layer wherein zinc (Zn) is the major element by weight. One of the metallic anti-corrosion and anti-galling layers is coated with a passivation layer and the other is at least partially coated with a lubricant layer.

A threaded tubular connection for drilling or operating hydrocarbon wells contains a portion of a tubular element with a male end having an axis of revolution and provided with a first threading extending about the axis of revolution, the male end portion being complementary with a portion of a tubular element with a female end having an axis of revolution and provided with a second threading extending about the axis of revolution, the male and female end portions being capable of being connected by makeup, each of the male and female end portions further comprising a sealing surface with a metal-metal interference, wherein the threading and the sealing surfaces of the male and female end portions are coated with a metallic anti-corrosion and anti-galling layer wherein zinc (Zn) is the major element by weight. One of the metallic anti-corrosion and anti-galling layers is coated with a passivation layer and the other is at least partially coated with a lubricant layer.

The invention describes a traction drive fluid that comprising a carrier and a particulate solid. The carrier has a boiling point of greater than at least about 100° C., and a melting point of below about 10° C., both being measured at 1 atm pressure. The particulate solid consists of a plurality of laminae. The laminae are homogeneously distributed through the carrier.

A method for lubricating an internal combustion engine, the method including: supplying a lubricating oil composition to a cylinder of an internal combustion engine, wherein the internal combustion engine has a mean effective pressure of no less than 1.3 MPa, wherein an integrated intensity ratio of peaks of CaO in a X-ray diffraction spectrum of an ash is no more than 16.5%, the ash being obtained by incinerating the lubricating oil composition in an air at 950° C.

A method for lubricating an internal combustion engine, the method including: supplying a lubricating oil composition to a cylinder of an internal combustion engine, wherein the internal combustion engine has a mean effective pressure of no less than 1.3 MPa, wherein an integrated intensity ratio of peaks of CaO in a X-ray diffraction spectrum of an ash is no more than 16.5%, the ash being obtained by incinerating the lubricating oil composition in an air at 950° C.

A lubricating composition comprising a base oil and one or more additives, wherein the composition has: a sulphated ash content (according to ASTM D 874) of at least 0.4 wt % and at most 1.0 wt. %, by weight of the lubricating composition; a total base number (TBN) value (according to ASTM D 2896) of at least 4.0 mg KOH/g and at most 12 mg KOH/g; a total aromatics content contributed by the base oil in the range from 1 wt % to 30 wt %, by weight of the lubricating composition; and a sulphur content contributed by the base oil of 0.4 wt % or less, by weight of the lubricating composition; and wherein the base oil comprises a blend of (i) a first base oil which is a mineral base oil selected from an API Group I mineral base oil and an API Group II mineral base oil, and mixtures thereof, and (ii) a second base oil selected from an API Group II base oil and an API Group III base oil, preferably wherein the first base oil belongs to a different API group to that of the second base oil.

A composition comprising from about 40 weight percent to about 99.9 weight percent of at least one C.sub.1-C.sub.5 hydrofluorocarbon, from about 0.1 weight percent to about 50 weight percent of CF3I, and from about 0.1 weight percent to about 10 weight percent of at least one C.sub.1-C.sub.6 hydrocarbon and the use of these composition for in methods of the recharging of refrigeration systems.

A lubricant additive for introduction into an AC/R system to improve lubricant miscibility and performance in the AC/R system.

The use of a composition including a polyol ester-based lubricant and a refrigerant F including at least one tetrafluoropropene and at least one hydrofluorocarbon, in a heat transfer system containing a vapour compression circuit including an oil separator. A heat transfer system including a vapour compression circuit containing a composition including a polyol ester lubricant, and a refrigerant F including at least one tetrafluoropropene and at least one hydrofluorocarbon, as a heat transfer composition, said vapour compression circuit including an oil separator.

A composition for a heat cycle system and a heat cycle system employing the composition are provided. The composition has favorable lubricating properties and contains a working fluid for heat cycle and a refrigerant oil. The working fluid has a low global warming potential and can replace R410A. The working fluid contains an unsaturated fluorinated hydrocarbon compound having a specific structure. The refrigerant oil has a breakdown voltage of at least 25 kV, a hydroxyl value of at most 0.1 mgKOH/g, and a kinematic viscosity at 40° C. of from 5 to 200 mm.sup.2/s and a kinematic viscosity at 100° C. of from 2 to 30 mm.sup.2/s.