Abstract: An apparatus and method of heat exchange in which a liquified gas is evaporated in a first coil disposed in a fluid heat exchange medium in a heat exchanger, absorbing heat by the evaporating liquid to chill the heat exchange medium, disposing in the heat exchange medium in the heat exchanger a second coil containing heat exchange medium in fluid connection with a body of heat exchange medium contained in a reservoir, chilling the heat exchange medium in the heat exchanger and circulating chilled heat exchange medium to the reservoir and from the reservoir to a facility location needing cooling, returning warmed heat exchange medium from the facility location to the reservoir and thence to the second coil for rechilling and reuse.

Abstract: A powder metallurgy material for use in the manufacture of electrical contacts and having enhanced cold workability consists essentially, by weight percent, of 5 to 20% tin oxide, 2000 to 5000 ppm, preferably 2000 to less than 4000 ppm copper, 20 to 200 ppm, preferably 20 to 100 ppm, lithium, balance silver. Such materials are produced by compacting the powdered components and heating to sinter the material to at least 93% of theoretical density. Such materials subsequently can be hot or cold worked to a form useful for the manufacture of electrical contacts.