A nonvolatile resistive memory element includes an oxygen-gettering layer. According to one aspect, the apparatus comprises a second bar optionally configured to be placed on a horizontal surface, and a first bar configured to be movable along and being perpendicular to said second bar and an optional control unit. The interlocking members have interfitting horizontal hook portions positioned to permit each movable sash frame to move freely between a closed position and an open position. To minimize the structural space occupied by the unit, at least one first partial air stream flows through a first assigned subregion of the heating unit in a first direction, and at least one second partial air stream flows through a second assigned subregion of the heating unit in a second direction opposed to the first direction.