Abstract: Air-buoyant structures, and vehicles incorporating air-buoyant structures, are provided. Hollow, air-buoyant structures may include a shell of ultra-low density aerogel material, foam material, or vapor-expanded material that is strong and stiff enough to withstand atmospheric pressure and lightweight enough to achieve buoyancy in air under evacuation. The shell may be reinforced with a suitable reinforcing material, such as helical nanofibers. The air-buoyant structures may also include vacuum pumps and valves operably connected to or integrated with the hollow shell. The vacuum pumps and valves may be configured to pump air out of the hollow shell and allow air back into the hollow shell to control buoyancy.

Abstract: A superconducting article comprising a substrate and a single composite layer deposited onto said substrate, wherein said single composite layer comprises Y2O3 and Al2O3, has a thickness of from about 20 nm to about 700 nm, and wherein the ratio of aluminum to yttrium is from about 10:1 to about 1:10; and wherein said superconducting article has a critical current density of at least 1 MA/cm2.