Abstract: A method (300) of texturing silicon surfaces (116) such to reduce reflectivity of a silicon wafer (110) for use in solar cells. The method (300) includes filling (330, 340) a vessel (122) with a volume of an etching solution (124) so as to cover the silicon surface 116) of a wafer or substrate (112). The etching solution (124) is made up of a catalytic nanomaterial (140) and an oxidant-etchant solution (146). The catalytic nanomaterial (140) may include gold or silver nanoparticles or noble metal nanoparticles, each of which may be a colloidal solution. The oxidant-etchant solution (146) includes an etching agent (142), such as hydrofluoric acid, and an oxidizing agent (144), such as hydrogen peroxide. Etching (350) is performed for a period of time including agitating or stirring the etching solution (124). The etch time may be selected such that the etched silicon surface (116) has a reflectivity of less than about 15 percent such as 1 to 10 percent in a 350 to 1000 nanometer wavelength range.

Abstract: A highway guard rail bumper guard includes at least two automobile tires arranged concentrically one within the other. Each of the tires has a mirror circumferential segment thereof removed to provide each of such tires with a pair of spaced ends. The tires preferably are positioned such that the spaced ends of the respective tires are substantially aligned radially. Fastening means are secured to the outermost of the tires adjacent each of the ends thereof and clamping means is connected between the fastening means. An annularly extending layer of a particulate non-compressible material is disposed within the innermost of the tires.