Abstract: An apparatus for classifying polydisperse aerosols includes aerosol and sheath gas conduits for conducting a sample aerosol and a sheath gas toward a merger area. At the merger area the sheath gas and about ten percent of the sample aerosol merge, then travel through a differential mobility analyzer (DMA) and along a tubular electrode of the DMA. Selected particles, i.e. particles having electrical mobilities within a narrow range, pass through a collection aperture of the electrode. The DMA output, an aerosol consisting of the selected particles, is provided to a condensation particle counter or other device for determining the aerosol concentration. The remainder of the sample aerosol is conducted away from the merger area along a bypass flow conduit. The bypass flow and an improved aerodynamic design provide for a slit at the merger area that is sufficiently narrow to minimize unwanted electric field penetration at the slit and DMA entrance.

Abstract: An electrospray nebulizer generates an aerosol comprised of submicrometer droplets substantially uniform in size. A liquid sample is supplied at a controlled rate to a capillary needle of the nebulizer, and droplets are formed due to an electrical field in the region about the needle discharge. The tendency of the droplets to disintegrate due to Coulomb forces is counteracted by sources of ionizing radiation within the nebulizer. The ions reduce the charge in each droplet while solvent evaporation reduces the diameter of the droplet. To further ensure against Coulomb disintegration, a controlled air sheath is introduced to the nebulizer for transporting droplets more rapidly downstream. Optionally, solvent vapor can be introduced into the air flow to reduce the rate of solvent evaporation within the nebulizer, and ions can be added to the air flow upstream of the needle discharge.

Abstract: A centrifugal pump for left ventricle assist includes a pump housing forming an impeller chamber with inlet and outlet passages and enclosing an impeller rotatable to move blood or other fluids through the impeller chamber, and a rotor chamber enclosing a rotor integral with the impeller and rotatable to drive the impeller. A stator is mounted outside of a rotor casing forming the rotor chamber, concentric with, radially outward of and approximately axially aligned with the rotor. The stator includes a stator frame with an annular back iron and twenty-four teeth equally spaced apart and projected radially inwardly of the back iron. Three wires, one for each of three motor phases, are wound about the back iron, each including four symmetrically arranged active segments toroidally wound about the back iron, corresponding to four poles in a permanent magnet fixed to the rotor.

Abstract: A centrifugal pump for left ventricle assist includes a pump housing forming an impeller chamber with inlet and outlet passages and enclosing an impeller rotatable to move blood or other fluids through the impeller chamber, and a rotor chamber enclosing a rotor integral with the impeller and rotatable to drive the impeller. A stator is mounted outside of a rotor casing forming the rotor chamber, concentric with, radially outward of and approximately axially aligned with the rotor. The stator includes a stator frame with an annular back iron and twenty-four teeth equally spaced apart and projected radially inwardly of the back iron. Three wires, one for each of three motor phases, are wound about the back iron, each including four symmetrically arranged active segments toroidally wound about the back iron, corresponding to four poles in a permanent magnet fixed to the rotor.

Abstract: A centrifugal pump for left ventricle assist includes a pump housing forming an impeller chamber with inlet and outlet passages and enclosing an impeller rotatable to move blood through the impeller chamber, and a rotor chamber enclosing a rotor integral with the impeller and rotatable to drive the impeller. An elastically deformable seal member separates the rotor and impeller chambers, and includes an annular lip seal surrounding a shaft which joins the impeller and rotor. A saline solution is supplied at a constant fluid flow rate to the rotor chamber through an inlet passage, and leaves the rotor chamber by perfusing into the impeller chamber along the interface between the shaft and lip seal. The saline solution thus provides hydrodynamic bearings between the rotating shaft and rotor, and the fixed pump housing and lip seal, and further prevents blood in the impeller chamber from entering the rotor chamber.