Abstract: An access structure such as a petroleum products loading platform which includes a vertically moving work platform having guides restrained with a plurality of vertical support members to vertically guide the platform along the support members. A plurality of lifting elements are respectively connected to each of the support members and to the platform to vertically move the platform along each of the support members. A common actuatable power arrangement is connected to each of the lifting elements to cause the lifting elements to vertically move the platform a prescribed distance along each of the support members responsive to each actuation of the power arrangement. Each of the lifting elements may be a hoisting drum and cable arrangement which is vertically moveable responsive to rotation of the hoisting drum to reel in or pay out the cable.

Abstract: A vitreous enamel resistor material comprising a mixture of a vitreous glass frit, an insulating material containing an oxide of zirconium, and a conductive phase of fine particles of tin oxide. The insulating material is selected from the group consisting of zirconia (ZrO.sub.2), calcium zirconate (CaZrO.sub.2), barium zirconate (BaZrO.sub.3) and strontium zirconate (SrZrO.sub.3), and the conductive phase may also contain an additive such as tantalum oxide. An electrical resistor is made from the resistor material by applying the material to a substrate and firing the coated substrate to a temperature at which the glass softens. Upon cooling, the substrate has on the surface thereof a film of glass and insulating material having the particles of the conductive phase embedded therein and dispersed therethroughout. The resistor material provides a resistor having relatively high resistivity as well as rugged physical characteristics.

Abstract: A vitreous enamel resistor material comprising a mixture of a vitreous glass frit, an insulating material containing an oxide of zirconium, and a conductive phase of fine particles of tin oxide. The insulating material is selected from the group consisting of zirconia (ZrO.sub.2), calcium zirconate (CaZrO.sub.2), barium zirconate (BaZrO.sub.3) and strontium zirconate (SrZrO.sub.3), and the conductive phase may also contain an additive such as tantalum oxide. An electrical resistor is made from the resistor material by applying the material to a substrate and firing the coated substrate to a temperature at which the glass softens. Upon cooling, the substrate has on the surface thereof a film of glass and insulating material having the particles of the conductive phase embedded therein and dispersed therethroughout. The resistor material provides a resistor having relatively high resistivity as well as rugged physical characteristics.