The present invention relates to pre-blend cement for general-purpose concrete construction containing Class-F fly ash, Class-C fly ash or slag, and less than about 5 percent of sodium thiocyanate andor calcium nitrate 2), as a substantial replacement for cement. The cyclic prefix has a dynamically variable length. The x-ray source plus the x-ray optics has a brilliance of at least 5*107 countssec mm2, preferably at least 1*108countssec mm2. The apparatus includes a processor configured to collect environment information of each zone of a plurality of zones, and determine an energy efficiency level of each zone of the plurality of zones based on the environment information. The method further includes displaying one or more photos of the end users and providing a label on the photos that certifies the photos as being substantially accurate. In some embodiments, a lighting fixture comprises a paddle configured to move in one or more directions and a set of one or more heat generating lighting elements mounted on the paddle.