Abstract: A process for preparing substantially pure enantiomers of formula (I) ##STR1## where the * represents a chiral center, x is 0 or 1, in exo-, endo- or a mixture of exo- and endo- forms; and R is hydrogen, alkyl or aralkyl, via diastereomers of formula (IIA) or (IIB): ##STR2##

Abstract: An electrostatic precipitator comprises an upright cylindrical vessel (10) containing a number of vertically spaced precipitator stages (12). Ducting (18) provides a path for gas flow from an inlet (14) to an outlet (15) passing successively through each of the precipitator stages (12).

Abstract: An electro-precipitator discharge electrode comprises connected upper and lower sections and each section comprises an elongated mast tube, a plurality of principal cross members, and a plurality of twisted discharge wires extending between the cross members and fixed therein by crimping. Upper and lower auxiliary cross members are provided to give longitudinal rigidity to the discharge electrode.

Abstract: The insulative stand-off is mounted on a frame and supports a heating coil. In the preferred embodiment the coil loops engage retention surfaces inside the inverted T-shaped opening in the end of the stand-off. The sides of the stand-off forming the opening have cam surfaces which squeeze adjacent central loops together during mounting while the loops adjacent the central loops are deflected to the outside of the stand-off. When the central loops reach the crossbar of the T they spring apart to fix the coil. Other embodiments are shown--all have retention surfaces generally parallel to the coil loops and transverse the coil axis. Cam surfaces control access to the retention surfaces to deflect the loops as they are moved to the retention surfaces and the coil resiliency biases the loops into engagement with the retention surfaces when mounting is completed.

Abstract: To reduce the cost of construction and avoid alignment problems of its component parts, a non-welded construction of mast discharge electrode, as used in an electro-precipitator, comprises a tube having holes passing transversely therethrough, cross members frictionally secured in said holes, and at least two wires extending parallel to said tube and passing through holes in said cross members, the wires being secured in the holes also by friction. The cross members may be knurled so as to be gripped in the tube holes, the latter preferably being formed by means of a punching operation. The cross members may be crimped frictionally to secure the wires. The provision of a non-welded construction particularly at the wires avoids weakening the wires because of the welding, and distortion arising from the heat of welding. The cross members may alternatively be welded to the tube if desired.

Abstract: The coiled resistance heating wire is supported on electrical insulating stand-offs in a figure 8 pattern on each side of a metallic radiation panel. The radiation panel and the figure 8 arrangement of the coil each contribute to increased heat transfer to air flowing axially down the assembly in a duct and in combination result in even more efficient heat transfer.