TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Composition: The heat-transfer device further contains a compressor. The mechanical power generating device generates work from heat using Rankine cycle or modification method.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The heat-transfer composition comprises 54-56 wt.% trans-1,3,3,3-tetrafluoropropene (R-1234ze(E)) and 44-46 wt.% 1,1,1,2-tetrafluoroethane (R-134a). The heat-transfer composition does not contain other hydrofluorocarbon compound, carbon dioxide and/or hydrocarbon, or other component having heat transfer properties. The heat-transfer composition is less flammable than R-1234ze(E), 2,3,3,3-tetrafluoropropylene (R-1234yf), or mixture of R-1234yf and R134a. The heat-transfer composition has high flammable limit, high ignition energy and/or low flame velocity compared with R-1234ze(E), R-1234yf, or binary mixture of R-1234yf and R134a. The heat-transfer composition is non-flammable. The stabilizer is diene-based compound, phosphate, phenol compound and/or epoxide. The flame retardant is tri(2-chloroethyl)phosphate, (chloropropyl)phosphate, tri(2,3-dibromopropyl)phosphate, tri(1,3-dichloropropyl)phosphate, diammonium phosphate, halogenated aromatic compound, antimony oxide, aluminum trihydrate, polyvinyl chloride, fluorinated iodocarbon, fluorinated bromocarbon, trifluoro iodomethane, perfluoroalkyl amine and/or bromo-fluoroalkyl amine. The composition (A), (B), (C) or (D) results in lower total equivalent warming impact, and/or a lower life-cycle carbon production than is attained by use of the existing compound or composition. The existing compound or composition is chosen from 1,1,1,2-tetrafluoroethane, 2,3,3,3-tetrafluoropropylene, 1,1-difluoroethane, and hydrofluorocarbon compound (R407B, R-404A, R-410A, R-507, R-407A, R-4070, R-407E and R-407F). Preferred Process: The preparation of composition (A), (B), (C) or (D) further involves removing at least some of the existing R-134a from the heat transfer device before introducing R-1234ze(E), and optionally lubricant, stabilizer and/or flame retardant.    TECHNOLOGY FOCUS - POLYMERS - Preferred Composition: The lubricant is chosen from mineral oil, silicone oil, polyalkyl benzene, polyol ester, polyalkylene glycol, polyalkylene glycol ester, polyvinyl ether and/or poly( alpha -olefin), preferably polyalkylene glycol or polyol ester.