Disclosed are refrigerants comprising at least about 97% by weight of a blend of three compounds, said blend consisting of: from about 40% by weight to about 49% by weight difluoromethane (HFC-32), from about 6% by weight to about 12% by weight pentafluoroethane (HFC-125), from about 33% by weight to about 40% by weight trifluoroiodomethane (CF.sub.3I); and from about 2% by weight to about 12% by weight of trans 1,3,3,3-tetrafluoropropene (trans HFO-1234ze), wherein the percentages are based on the total weight of the three compounds in the blend, and systems and method using same.

A friction control composition having high and positive frictional properties for sliding steel surfaces includes a water insoluble hydrocarbon that enables a reduced water content, a rheological additive, a freezing point depressant, a friction modifier, and a lubricant.

A friction control composition having high and positive factional properties for sliding steel surfaces includes a water insoluble hydrocarbon that enables a reduced water content, a rheological additive, a freezing point depressant, a friction modifier, and a lubricant.

To provide a composition for a heat cycle system, which comprises a working fluid for heat cycle which has a low global warming potential and high stability, and which can replace R410A, and a heat cycle system employing the composition.

A composition for a heat cycle system, which comprises a working fluid for heat cycle containing 1,2-difluoroethylene, and a stabilizer for preventing deterioration of the working fluid for heat cycle, such as an oxidation resistance-improving agent, a heat resistance-improving agent or a metal deactivator, and a heat cycle system employing the composition for a heat cycle system.