Abstract: Embodiments relate to use of Limestone Rock Aggregate (“LRA”) as a component used to manufacture clinker, wherein the clinker is used in the manufacture of Portland cement. LRA is a naturally occurring limestone deposit that has been impregnated with various bituminous and hydrocarbon components, including asphaltenes and lighter hydrocarbons. Because of the presence of hydrocarbon components, LRA is “energy positive” making it easier (e.g., requiring less energy) to kiln heat than pure, or common, limestone. As will be explained herein, the LRA can be treated before being used as a component cement manufacture. The treatment of the LRA can involve removal, or extraction, of certain bituminous material (e.g., light hydrocarbons from the LRA). This extracted bituminous material can be used in other material processes (e.g., crude oil refining). The treatment of LRA can also involve manipulating the gradation of crushed LRA material to improve its minerology for cement production.

Abstract: A switchable window apparatus capable of being placed in a transparent condition in which light passes through the window unobstructed, and in an obstructed condition in which light passing through the window is obstructed by an optical element in the window. The switchable window apparatus is placed in the transparent state by contacting a lens element with a material of matching refractive index, and placed in the obstructed state by contacting the lens element with a material with a non-matching refractive index.