Abstract: A blade holder assembly including a casing having a series of teeth along one side for smoothing the hairs or whiskers to be cut and a center opening, a slide plate received in the casing and two bottom mounting rods extended out of the center opening of the casing and coupled to a reciprocating mechanism, a lower blade holder coupled to the slide and having a series of fine cutting teeth and a series of coarse cutting teeth disposed at two opposite sides, an upper cutter blade having a series of fine cutting teeth at one side acted against the fine cutting teeth of the lower blade holder to cut hairs or whiskers, and an upper blade holder fastened to the casing to hold the upper cutter blade above the lower blade holder and having a sloping wall at one side pressed on the upper cutter blade and a series of coarse cutting teeth at an opposite side acted against the coarse cutting teeth of the lower blade holder to cut hairs or whiskers.

Abstract: A process for etching copper with an ammoniacal etchant solution and reconditioning the etchant solution which consumes only feeds of oxygen and water for etching copper and only small amount of pollutant is obtained.

Abstract: Polyurethane elastomers, low density high resiliency polyurethane foams and compositions and processes for preparing urethane foams and elastomers comprising reacting a mixture of a polyalkylene polyol having reactive hydrogen atoms as determined by the Zerewitinoff method exhibiting a molecular weight of at least 500, at least one organic polyisocyanate, and as a cross-linking agent at least one sulfur-containing polyamine compound exhibitng the formula: ##STR1## wherein R is a hydrocarbon, and R' is selected from the group consisting of hydrogen, halogens, and hydrocarbons.