Abstract: A surface is selectively marked by using a coating containing quantum dots. When exposed to an energizing source, the quantum dots emit colored light to selectively mark the surface. In an embodiment, a green artificial turf field is marked with two sets of lines, white for football and yellow for soccer. The football lines are normally visible, but are also embedded with quantum dots that emit green light when energized. The soccer lines are normally invisible (clear), but emit yellow light when energized. The field can be used for football without energizing the quantum dots. To use the field for soccer, the field is exposed to a constant source of UVC energy. The quantum dots in the football lines emit green light when energized, causing them to become green, blending in with the normal green color of the artificial turf field. The quantum dots in the soccer lines emit yellow light when energized. Only the soccer lines are then visible, thus eliminating confusion for the players and officials.

Abstract: A surface is selectively marked by using a coating containing quantum dots. When exposed to an energizing source, the quantum dots emit colored light to selectively mark the surface. In an embodiment, a green artificial turf field is marked with two sets of lines, white for football and yellow for soccer. The football lines are normally visible, but are also embedded with quantum dots that emit green light when energized. The soccer lines are normally invisible (clear), but emit yellow light when energized. The field can be used for football without energizing the quantum dots. To use the field for soccer, the field is exposed to a constant source of UVC energy. The quantum dots in the football lines emit green light when energized, causing them to become green, blending in with the normal green color of the artificial turf field. The quantum dots in the soccer lines emit yellow light when energized. Only the soccer lines are then visible, thus eliminating confusion for the players and officials.

Abstract: A circular hole large enough to support a variety of beverage containers is formed in a food tray and surrounded by a lip about the height of the lip around the edge of the tray. A flexible mesh is integrated into the hole. The material of the mesh stretches below the food service tray when a beverage container is placed in the hole, and return to a position level with the surface with the food service tray when the beverage container is removed. A semi-mesh embodiment includes a disc of rigid material at the center of the mesh.