Abstract: A propeller according to an embodiment includes a hub and a series of blades extending outward from the hub. Each blade of the series of blades includes a core and a skin covering the core. The core may be formed of a ceramic first material and the skin is formed of a second material different than the ceramic first material. The ceramic first material of the core may be ceramic Si3N4 (silicon nitride), yttria-toughened zirconia ceramic, or alumina-zirconia ceramic, and the second material of the skin may be a polymer. The polymer skin is configured to function as a shock absorber protecting the ceramic core, and the ceramic core is configured to provide rigidity to maintain the shape of the propeller blades under aerodynamic loading, which enables improved aerodynamic efficiency and reduced noise generation.

Abstract: A lock for lavatory plumbing fixtures includes one or more griping members adapted to receive and attach to an internal rim of the lavatory fixture bowl. At least one of the gripping members can be translationally adapted or slideably engaged. A keyed rotational lock or a padlock can be incorporated for locking the article in place. Alternatively, a screw having a special head can be utilized to prevent unauthorized unlocking of the article.

Abstract: A lock for lavatory plumbing fixtures includes one or more griping members adapted to receive and attach to an internal rim of the lavatory fixture bowl. At least one of the gripping members can be translationally adapted or slideably engaged. A keyed rotational lock or a padlock can be incorporated for locking the article in place. Alternatively, a screw having a special head can be utilized to prevent unauthorized unlocking of the article.