Abstract: There is provided solar energy harvesting apparatus (20) including a clear polycarbonate body (21) including a transparent front face (23) and supporting a thermal absorber (27) adapted to absorb incident solar radiation. The thermal absorber (27) transfers heat via a fluid connector (28) to a circulated-fluid system and in addition controls the temperature of a photovoltaic element (24) mounted on the absorber (27) and connected to an electrical harness by electrical connectors (25, 26). The polycarbonate body (21) has complementary edge mating profiles (32, 33) engaging with a standard-tiled roof structure to replace some of the standard tiles thereof, and is secured conventionally to roof battens by a batten screw (29).

Abstract: Disclosed is a method for the detection and quantification of defects in transparent substrates and, more particularly, in glass sheets. The method comprises providing a transparent planar substrate having a top surface and a bottom surface. The surface topography of at least a portion of the top surface of the provide transparent planar substrate is measured to obtain a three dimensional top surface profile having a sub-nanometer level of precision. From the three dimensional surface profile measurement, the existence of one or more surface variations in the three dimensional surface profile having an amplitude greater than a predetermined tolerance can be identified and/or quantified.

Abstract: The present invention relates to an improved process for the recovery, individually, of natural gas liquids methane and nitrogen from a gaseous feed stream such as natural gas without the need for auxiliary refrigeration and without or with only minimal need for supplemental compressor or pumping equipment. The gaseous feed stream is separated in multiple steps utilizing process-derived streams and minimal pressure reductions to achieve and provide the refrigeration requirements necessary to effect the separation.

Abstract: An improved process for cryogenically separating a helium-bearing natural gas stream comprising subjecting the natural gas stream to a sequence of alternating cooling and separating steps wherein one or more process-derived streams are utilized to effect cooling of the natural gas streams to temperatures in the cryogenic range. The process provides for the separation and recovery of a natural gas liquids product stream consisting substantially of condensed C.sub.2 and higher hydrocarbons and a gaseous product stream consisting of at least 50 volume percent of helium with the balance being substantially nitrogen.