A gel is produced by magnetically treating and mixing two solutions and in one embodiment subsequently introducing carbon dioxide gas. A flexible slot cover is provided to cover the open slot disposed between light fixtures. The liquid crystal element is driven by electric signals and provided on a light path between the light source and the object scanning surface. The resistive element generates thermal energy based on a current received from a power source. Three models including a mean-value cylinder flow model, a manifold dynamics model, and a throttle flow model are provided to estimate the air charge in the at least one combustion cylinder and to control delivery of fuel to the fuel delivery system.