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: An unmanned aerial system includes an unmanned aerial vehicle having a body and a primary propulsion system coupled to the body. The primary propulsion system includes at least one propeller and at least one motor coupled to the at least one propeller. The unmanned aerial system also includes a pair of landing gears coupled to the body of the unmanned aerial vehicle. Each landing gear of the pair of landing gears includes a buoyant elongated float. The unmanned aerial system also includes a SONAR device coupled to the unmanned aerial vehicle.

Abstract: A touchless activation system comprising an infrared detector configured to detect an object within a target range, wherein an initial reading is measured by the infrared detector. A second sensor operatively connected to the infrared detector, wherein the second sensor is turned on when the initial reading is measured. The infrared detector measures whether the object is within the target range by comparing the initial reading with an object initiated reflection and determining if a predetermined threshold is exceeded, wherein the second sensor is configured to receive a system activation request. An activator mechanism configured to process the system request and cause the touchless activation system to execute an action associated with the system request. The system is configured to flush a toilet or other plumbing fixture, wherein the system request causes the activator mechanism to flush a toilet.

Abstract: An end-of-service indicator for use with a respirator cartridge, the end-of-service indicator having an optical waveguide having two extremities, one of the extremities being connected to a light source, the other of the extremities being connected to a detector which measures the intensity of light guided and transmitted by the fiber. An alarm is connected to the detector and is triggered when the intensity of light measured by the detector is below a predetermined level. An important aspect of the end-of-service indicator is that at least a portion of the optical fiber is porous. In use, the end-of-service indicator is placed inside a respirator cartridge having a gas/vapor sorbent, so that when the respirator cartridge is used in a toxic environment, the gas/vapor sorbent and the porous glass gradually become saturated.