Abstract: A glass structure for controlled permeability of gases includes a glass vessel. The glass vessel has walls and a hollow center for receiving a gas. The glass vessel contains a metal oxide dopant formed with at least one metal selected from the group consisting of transition metals and rare earth metals for controlling diffusion of the gas through the walls of the glass vessel. The vessel releases the gas through its walls upon exposure to a radiation source.

Abstract: A process for preparing a surface-darkened glass is disclosed. In the first step of this process, a specified silicate glass which contains a minor amount of antimony trioxide is provided. Thereafter, this glass is heated to a temperature of from about 350 to about 1,000 degrees Celsius while being contacted with hydrogen-containing gas. The presence of the antimony trioxide in the glass facilitates the darkening of its surface.

Abstract: A process for preparing a surface-darkened glass is disclosed. In the first step of the process, a specified alkali alumino-borosilicate glass which contains a minor amount of antimony trioxide is provided. Thereafter, this glass is heated to a temperature of from about 350 to about 1,000 degrees Celsius while being contacted with hydrogen-containing gas. The presence of the antimony trioxide in the glass facilitates the darkening of its surface.

Abstract: A knee pad for use on a supporting surface, and not attached to a person's knee, to provide support and cushioning to a person's knee. The pad has a lower region having a bottom for contacting the supporting surface, and a contoured upper region for contacting the front portion of the person's knee. The bottom has a frictional surface to resist sliding with respect to the supporting surface. Various properties of the upper region, relating to its contours and fitting with respect to the knee, are disclosed, particularly a concavity in the top of the pad. The concavity may be vacant. The top of the concavity may adjoin the top of the pad. The concavity may have a secondary inner concavity perimeter. The pad may have a plurality of outer perimeters, defining decreasing areas within the perimeters, from bottom to top of the pad.