Abstract: A solar chimney assembly including a chimney (1) for receiving fluid from a solar heat collector (6, 7), and a turbine (2) driven by the fluid. The solar heat collector, which increases the moisture content and the temperature of the air flowing past the turbine, has an evaporative area (6) and a non-evaporative area (7). The non-evaporative area acts as a heat absorbing area and has a first cover (8) which inhibits evaporation of a heat-absorbing liquid retained therein. The evaporative area has a second cover (4) connected to the chimney and arranged to contain vapor evaporating from a liquid in the evaporative area. The assembly is constructed to transfer thermal energy from the liquid of the non-evaporative area to liquid of the evaporative area, for high efficiency operation.

Abstract: A segmented chimney constructed from separate inflated chimney units mounted one on top of another. Each chimney unit has a segmented side wall, the segments being individually movable relative to the unit.

Abstract: A diamond sawing process, in which guidelines on the outer surface of a rough diamond are used for the sawing of up to six pyramid shapes (340) as fragments from a particular piece of tetrahedron shaped (sawable) diamond, whereby the maximum weight of a polished round brilliant cut (or other round cut diamond) is obtained from a particular rough diamond, together with the fragments. A marking pen or equivalent is held parallel to the center line of the diamond (300), and adjusted so that its point (330) touches the shortest side of the diamond; when the diamond is rotated relative to the point, a circle is marked which represents the maximum round diameter that can be cut for that diamond. The pen crosses the ridges (412, 414, 416, 418) of the diamond, and these crossing points define the starting point of sawing.

Abstract: A method of fabricating a hollow jewelry object in which an electrically conductive coating is applied to part (18) of a non-conductive mandrel or mould (10), the coated mandrel being presented for a first dip into an electrolyte containing ions of a precious metal e.g. gold so that the parts of the mandrel are coated with an initial deposit; the mandrel is then removed from the electrolyte and the previously uncoated portions (24) coated before the mould is again dipped in the or a different electrolyte to form an outer shell integral with the internal ribs or points formed during the first dip. Thus the hollow jewelry object is internally strengthened by the ribs; though in an alternative embodiment the ribs can be replaced by individual upstanding projections in bas relief if these conform to the external profile required for the jewelry object. The invention also includes a hollow jewelry object formed by the method according to the invention.

Abstract: A barometric direct-contact steam condenser (10) in which a stream of vapor and formed condensate contacts a free surface of the condensate, which surface is preferentially removed, preferably continuously, so as to provide a cooler surface against which and/or as a result of which more vapor can condense.

Abstract: A steam plant which includes a steam driven turbine, and a condenser in which the steam exhausted from the turbine is condensed, the condenser being at least 200 meters above the level of the turbine and preferably several kilometers above the turbine level. The turbine is connected to the condenser by a vacuum tight shaft adapted to convey the spent steam upwardly to the condenser at vapor speeds up to 0.75 of the speed of sound in that vapor. The condensate is continually withdrawn from the condenser both to maintain the vacuum and to stimulate continued mass transfer upwardly of the spent steam at high speed.

Abstract: A personal identification system wherein an encoded version of the user's fingerprint is reprint is recorded on an identification card or device; this encoded version is security machine-read and directly compared at the time of use with an impression of the fingerprint on a different but designated area of the card, or alternatively on a designated area of the machine-reader or a separate card, the comparison being done on a one-to-one basis so as to reduce the need for a large memory or storage capacity for fingerprint records on the card or in the security machine-reader. The personal identification system can be used with passports, travellers cheques, credit cards, cheque cards and the like.