Abstract: An agricultural sweep has a main body with a cutting edge including a tip and winged portions extending away from the tip. The tip and winged portions have hardfacing material on them. In the improvement, the width of the hardfacing material on the tip is greater than the width of the hardfacing material on the winged portions, thereby conforming the location of hardfacing material to a soil pressure gradient along the cutting edge. A new method for applying a hardfacing material to an agricultural sweep includes the steps of (a) determining a face pressure gradient resulting from soil passing across the face and applying hardfacing material to those portions of the face at which the gradient exceeds a predetermined value.

Abstract: A detector for sensing the electrical conductivity of planar surfaces, such as glass panels having an electrical conductive, low emissivity coating on one side thereon, includes a housing carrying a battery and an LED, and a pair of spaced apart contact elements electrically coupled to the battery and LED. Structure is provided for rigidly connecting the pair of contact elements to a outer wall of the housing and for supporting an outer portion of the contact elements a fixed distance away from the housing for enabling the outer portions of both of the contact elements to directly and simultaneously engage the planar glass coating as soon as the housing is shifted to a position adjacent the glass.