Abstract: An optical stack for reflecting and transmitting light in a predetermined wavelength range includes stacked first and second optical films, the predetermined wavelength range defining a first wavelength range and a remaining wavelength range. For normally incident light and for each wavelength in a first wavelength range, the first optical film substantially reflects light having a first polarization state, and substantially transmits light having a second polarization state. For each of the first and second polarization states, for wavelengths in the first wavelength range, the second optical film has a maximum optical transmittance Tmax for light incident at a first incident angle, and an optical transmittance Tmax/2 for light incident at a second incident angle, where the second incident angle is greater than the first incident angle by less than about 50 degrees. For wavelengths in the remaining wavelength range, the second optical film reflects at least 80% of light.

Abstract: Adsorbed gaseous species and elements in a carbon (C) powder and a graphite crucible are reduced by way of a vacuum and an elevated temperature sufficient to cause reduction. A wall and at least one end of an interior of the crucible is lined with C powder purified in the above manner. An Si+C mixture is formed with C powder purified in the above manner and Si powder or granules. The lined crucible is charged with the Si+C mixture. Adsorbed gaseous species and elements are reduced from the Si+C mixture and the crucible by way of a vacuum and an elevated temperature that is sufficient to cause reduction but which does not exceed the melting point of Si. Thereafter, by way of a vacuum and an elevated temperature, the Si+C mixture is caused to react and form polycrystalline SiC.

Abstract: A motorized treadmill exercising device comprising a generally planar frame equipped with a planar slider bed and head and tail rollers journalled respectively at the head and tail ends of the frame, over which an endless plastic belt is trained.

Abstract: A generally rectangular open topped vessel with vertical walls around the periphery of a floor consisting of two integrally formed levels, the lower level being at one end providing a footwell and having a drain therein. Near the end of one side wall, in the area where the footwell is located, is a door opening. This door opening has a ferromagnetic faced door stop around the edge. A door is hingedly attached to the edge of the opening such that it swings horizontally inward towards the nearest adjacent end wall. The door has a flange along its two vertical edges and along its bottom horizontal edge. Mounted concentrically on the flange are two magnetic gaskets such that when the door is closed the gakets force a water tight seal with the ferromagnetic plate on the door stop. A second drain is located in the surface of the bottom door stop such that when the door is closed water in the vessel cannot reach the drain due to the sealing of the outer gasket.