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: The present invention relates to an apparatus and a method to spin hollow fibres of dialysis grade with diameter around 220 microns and thickness of around 35-40 microns, by wet spinning technique. The present invention spinning is carried out by using an apparatus having a nitrogen cylinder (1), water bucket (2), polymer cylinder (6), water cylinder (7), automatic winding machine (5) characterized by a cheap assembly of syringes (dispo van (8) and insulin syringes (9)) wherein no electrical power is required for the spinning, making the fibres extremely easy to manufacture and affordable at the consumer end.

Abstract: Apparatus for controlled raising and lowering of a barrier about a pivot point in which optimum control forces are applied to the barrier throughout its range of operation, and in which sensors are provided to prevent movement of the barrier against a resistive force to thereby prevent damage to the barrier, its operative mechanism, or an external object in its path.