Many acres of land around the world have been given over to wind turbines to produce much needed electricity from what have been euphemistically termed "wind farms." They create a great deal of noise and some people find them unsightly.
A practical generator. In this diagram the iron core that fills the space between the axle and the rotating coils has been removed for clarity. The magnetic field is provided by the two electromagnet coils ('field windings') which also have iron cores.
Self-Healing Concrete Uses Bacteria, Activated by Water, to Fill Cracks, Dutch researchers from TU Delft, have infused concrete with the bacillus bacteria to create a bio-concrete that has the ability to self-repair
Getting Your Energy Source From the Sun May Save You