laboratories, s is used as an extraction solvent, for example for determining total recoverable hydrocarbons from soils, sediments, fly-ash and other media, and determination of polycyclic aromatic hydrocarbons in soil and solid wastes. Supercritical fluid extraction has been used in determining hydrocarbon components in water. Processes that use s to produce micro and nano scale particles, often for pharmaceutical uses, are under development. The gas antisolvent process, rapid expansion of supercritical solutions and supercritical antisolvent precipitation (as well as several related methods) process a variety of substances into particles. Due to its ability to selectively dissolve organic compounds and assist the functioning of enzymes, s has been suggested as a potential solvent to support biological activity on Venus- or super-Earth-type planets. Manufactured products Environmentally beneficial, low-cost substitutes for rigid thermoplastic and fired ceramic are made using s as a chemical reagent. The s in these processes is reacted with the alkaline components of fully hardened hydraulic cement or gypsum plaster to form various carbonates. The primary byproduct is water. Supercritical carbon dioxide is used in the foaming of polymers. Supercritical carbon dioxide can saturate the polymer with solvent. Upon depressurization and heating the carbon dioxide rapidly expands, causing voids within the polymer matrix, i.e., creating a foam. Research is also ongoing at many universities in the production of microcellular foams using s. An electrochemical carboxylation of a para-isobutylbenzyl chloride to ibuprofen is promoted under s. Working fluid Supercritical is chemically stable, reliable, low-cost, non-flammable and readily available, making it a desirable candidate working fluid for transcritical cycles. Supercritical is used as the working fluid in high efficiency domestic water heat pumps. Manufactured and widely used, heat pumps are also commercially available for domestic and business heating and cooling. While some of the more common domestic water heat pumps remove heat from the space in which they are located, such as a basement or garage, the heat pump water heaters are typically located outside, where they remove heat from the outside air. Power generation The unique properties of s present advantages for closed-loop power generation and can be applied to various power generation applications. Power generation systems that use traditional air Brayton and steam Rankine cycles can be upgraded to s to increase efficiency and power output. The relatively new Allam power cycle uses s as the working fluid in combination with fuel and pure oxygen. The produced by combustion mixes