Abstract: A motor system includes a motor having a rotor with a plurality of magnetic poles disposed adjacent a plurality of stator elements. Motion of the rotor is responsive to a change in magnetic flux from the stator elements. A generator comprising one or more coils and/or pickups is configured to generate electromagnetic signals responsive to the motion of the rotor, the change in flux from the stator elements, or both. A controller is configured to generate power from the signals, for operating a processor with memory. The processor and memory are configured to receive the signals, determine a count of cycles and/or direction changes of the motor based on the signals, and store the count in the memory.

Abstract: Disclosed herein are systems and methods for measuring and controlling a flow rate through a particle counter or active air sampler. As disclosed herein, a fluid flows through a venturi tube and an orifice in the system at a predetermine velocity. A pressure differential between an inlet of the instrument and a throat section of the venturi tube is measured. The flow rate through the system can be determined based on the pressure differential and an intensive property of the fluid. An alarm can be activated when the flow rate is outside of a flow rate range.

Abstract: Disclosed herein are systems and methods for measuring and controlling a flow rate through a particle counter or active air sampler. As disclosed herein, a flow is created within a conduit fluidly connected to an instrument at a first velocity. An inlet pressure at an inlet of the instrument and an ambient pressure proximate the instrument are measured. The flow rate through the instrument is determined based on a pressure differential between the inlet pressure and the ambient pressure. The flow rate is increased or decreased when the flow rate is outside a flow rate range.

Abstract: A head-mounted display may include a display system and an optical system in a housing. The display system may have a pixel array that produces light associated with images. The display system may also have a linear polarizer through which light from the pixel array passes and a quarter wave plate through which the light passes after passing through the quarter wave plate. The optical system may be a catadioptric optical system having one or more lens elements. The lens elements may include a plano-convex lens and a plano-concave lens. A partially reflective minor may be formed on a convex surface of the plano-convex lens. A reflective polarizer may be formed on the planar surface of the plano-convex lens or the concave surface of the plano-concave lens. An additional quarter wave plate may be located between the reflective polarizer and the partially reflective mirror.

Abstract: A head-mounted display may include a display system and an optical system in a housing. The display system may have a pixel array that produces light associated with images. The display system may also have a linear polarizer through which light from the pixel array passes and a quarter wave plate through which the light passes after passing through the quarter wave plate. The optical system may be a catadioptric optical system having one or more lens elements. The lens elements may include a plano-convex lens and a plano-concave lens. A partially reflective mirror may be formed on a convex surface of the plano-convex lens. A reflective polarizer may be formed on the planar surface of the plano-convex lens or the concave surface of the plano-concave lens. An additional quarter wave plate may be located between the reflective polarizer and the partially reflective mirror.

Abstract: Systems and method for an electric toothbrush and charging dock. The electric toothbrush may include at least one magnetic member and at least one charging coil in a central portion. The charging dock may include at least one magnetic member and at least one transmitting coil. The charging dock may include a proximal portion which may be attached to a distal portion of the charging dock to be rotatable relative to the distal portion. The charging dock may include at least one unit capable of receiving power from a power source. The energy received by the unit from the power source may be transmitted to the transmitting coil. The energy may be transmitted from the transmitting coil to the receiving coil in the electric toothbrush via inductive or resonance charging. The energy may be transferred from the receiving coil to a battery in the electric toothbrush.

Abstract: A wheelchair can comprise: a frame comprising an upper portion and a lower portion that is coupled to the upper portion so that the upper portion is vertically adjustable with respect to the lower portion. A pair of drive wheels can be coupled to the frame. A plurality (e.g., a pair) of casters are coupled to the frame. Each caster can have a respective swivel axis. At least one caster of the plurality of casters can be configured to be locked to prevent swiveling about its respective swivel axis and unlocked to enable swiveling about its respective swivel axis.

Abstract: A head-mounted display may include a display system and an optical system in a housing. The display system may have a pixel array that produces light associated with images. The display system may also have a linear polarizer through which light from the pixel array passes and a quarter wave plate through which the light passes after passing through the quarter wave plate. The optical system may be a catadioptric optical system having one or more lens elements. The lens elements may include a plano-convex lens and a plano-concave lens. A partially reflective mirror may be formed on a convex surface of the plano-convex lens. A reflective polarizer may be formed on the planar surface of the plano-convex lens or the concave surface of the plano-concave lens. An additional quarter wave plate may be located between the reflective polarizer and the partially reflective mirror.

Abstract: A head-mounted display may include a display system and an optical system in a housing. The display system may have a pixel array that produces light associated with images. The display system may also have a linear polarizer through which light from the pixel array passes and a quarter wave plate through which the light passes after passing through the quarter wave plate. The optical system may be a catadioptric optical system having one or more lens elements. The lens elements may include a plano-convex lens and a plano-concave lens. A partially reflective mirror may be formed on a convex surface of the plano-convex lens. A reflective polarizer may be formed on the planar surface of the plano-convex lens or the concave surface of the plano-concave lens. An additional quarter wave plate may be located between the reflective polarizer and the partially reflective mirror.

Abstract: Various embodiments include methods and systems for reducing false-particle counts in a water-based condensation particle counter (CPC). One embodiment of a method includes delivering water into multiple wicks used for transporting separate portions of an aerosol sample flow, with the wicks extending from a wick stand on a first end to a flow joiner on a second end, combining particles from the separate portions of the aerosol sample flow into a single aerosol stream within the flow joiner prior to transporting the combined aerosol sample stream into a particle detection chamber within the CPC, sensing an excess volume of water delivered to the wicks, collecting the excess volume of water in a collection reservoir, and after receiving a signal corresponding to the excess volume of water, draining the excess volume of water from the collection reservoir. Other methods, systems, and apparatuses are disclosed.

Abstract: A head-mounted display may include a display system and an optical system in a housing. The display system may have a pixel array that produces light associated with images. The display system may also have a linear polarizer through which light from the pixel array passes and a quarter wave plate through which the light passes after passing through the quarter wave plate. The optical system may be a catadioptric optical system having one or more lens elements. The lens elements may include a plano-convex lens and a plano-concave lens. A partially reflective mirror may be formed on a convex surface of the plano-convex lens. A reflective polarizer may be formed on the planar surface of the plano-convex lens or the concave surface of the plano-concave lens. An additional quarter wave plate may be located between the reflective polarizer and the partially reflective mirror.

Abstract: Various embodiments include methods of reducing false-particle counts in a water-based condensation particle counter (CPC). One embodiment of a method includes delivering water into one or more wicks, sensing an excess volume of water delivered to the wicks, collecting the excess volume of water into a collection reservoir, and draining the excess volume of water from the collection reservoir. Other methods and apparatuses are disclosed.

Abstract: A head-mounted display may include a display system and an optical system in a housing. The display system may have a pixel array that produces light associated with images. The display system may also have a linear polarizer through which light from the pixel array passes and a quarter wave plate through which the light passes after passing through the quarter wave plate. The optical system may be a catadioptric optical system having one or more lens elements. The lens elements may include a plano-convex lens and a plano-concave lens. A partially reflective mirror may be formed on a convex surface of the plano-convex lens. A reflective polarizer may be formed on the planar surface of the plano-convex lens or the concave surface of the plano-concave lens. An additional quarter wave plate may be located between the reflective polarizer and the partially reflective mirror.

Abstract: Various embodiments include methods of reducing false-particle counts in a water-based condensation particle counter (CPC). One embodiment of a method includes delivering water into one or more wicks, sensing an excess volume of water delivered to the wicks, collecting the excess volume of water into a collection reservoir, and draining the excess volume of water from the collection reservoir. Other methods and apparatuses are disclosed.

Abstract: Various embodiments include methods of reducing false-particle counts in a water-based condensation particle counter (CPC). One embodiment of a method includes delivering water into one or more wicks, sensing an excess volume of water delivered to the wicks, collecting the excess volume of water into a collection reservoir, and draining the excess volume of water from the collection reservoir. Other methods and apparatuses are disclosed.

Abstract: A head-mounted display may include a display system and an optical system in a housing. The display system may have a pixel array that produces light associated with images. The display system may also have a linear polarizer through which light from the pixel array passes and a quarter wave plate through which the light passes after passing through the quarter wave plate. The optical system may be a catadioptric optical system having one or more lens elements. The lens elements may include a plano-convex lens and a plano-concave lens. A partially reflective mirror may be formed on a convex surface of the plano-convex lens. A reflective polarizer may be formed on the planar surface of the plano-convex lens or the concave surface of the plano-concave lens. An additional quarter wave plate may be located between the reflective polarizer and the partially reflective mirror.