Abstract: A resonator comprising a piezoelectric film which creates an acoustic path that is slightly longer in a central region of the resonator than at an edge of the resonator.

Abstract: A system for concentrating particles in an air stream includes an air channel having a first open end and a second open end. The air channel may be enclosed by a channel wall extending from at least the first open to the second open end. Two or more heater elements may be positioned between the first open end and the second open end. The heater elements may be positioned near a periphery of the air channel and cooperatively configured to force particles in the air stream away from the periphery and towards an interior region of the air channel. Particles in the air stream may be thermophoretically forced towards the interior region of the air channel when the heater elements are heated and thermal gradients emanating from the heater elements are generated.

Abstract: A method for analyzing particles in an air stream includes concentrating the particles in an interior region of the air stream and deflecting the concentrated particles in the air stream with a generated thermal gradient. Smaller particles in the air stream may be selectively deflected away from the interior region and towards a periphery of the air stream at a different rate than larger particles in the air stream. The generated thermal gradient may be controlled to deflect particles in a selected particle size range onto a surface of a particle detector. An effective mass of the collected particles and an aerosol mass concentration estimate of the particles within the selected particle size range may be generated. Systems for analyzing particles are also disclosed.

Abstract: A system for concentrating particles in an air stream includes an air channel having a first open end and a second open end. The air channel may be enclosed by a channel wall extending from at least the first open to the second open end. Two or more heater elements may be positioned between the first open end and the second open end. The heater elements may be positioned near a periphery of the air channel and cooperatively configured to force particles in the air stream away from the periphery and towards an interior region of the air channel. Particles in the air stream may be thermophoretically forced towards the interior region of the air channel when the heater elements are heated and thermal gradients emanating from the heater elements are generated.

Abstract: A resonator comprising a piezoelectric film which creates an acoustic path that is slightly longer in a central region of the resonator than at an edge of the resonator.

Abstract: A system for analyzing particles in an air stream includes a first heater element configured to deflect particles in an interior region of the air stream towards a peripheral wall of an air channel encompassing the air stream, a second heater element controllable to deflect the particles in a first lateral direction along the peripheral wall, and a third heater element controllable to deflect the particles in a second lateral direction along the peripheral wall. Thermal gradients in the air channel generated by the heater elements may thermophoretically force particles towards the peripheral wall in a direction perpendicular to the air stream to allow thermophoretic forcing and scanning of particles in either the first lateral direction or the second lateral direction along the peripheral wall and onto a surface of a particle detector. Systems and methods for scanning particles with thermophoretic forces are disclosed.

Abstract: A method for analyzing particles includes concentrating the particles in an interior region of an air stream, generating a thermal gradient to deflect the concentrated particles from the interior region of the air stream to a peripheral region of the air stream, receiving orientation information, and adjusting the thermal gradient in response to the received orientation information. The particles may be concentrated in the interior of the air stream with at least two heater elements positioned near a periphery of the air stream and configured to cooperatively force particles away from the periphery and towards the interior region of the air stream. The orientation information may include gravity vector component information or angular rate component information in one, two or three substantially orthogonal directions relative to the air stream. Various systems for airborne particle detection with orientation-dependent particle discrimination are disclosed.

Abstract: A resonator comprising a piezoelectric film which creates an acoustic path that is slightly longer in a central region of the resonator than at an edge of the resonator.

Abstract: A system for detecting and analyzing particles in an air stream includes an inlet, a particle concentrator and a particle discriminator having an air channel with a cross-sectional geometry that changes within at least one of the inlet, particle concentrator and particle discriminator. The system may have a sheath air stage including a port for providing sample air, at least one sheath air inlet port for providing sheath air, and a sheath air combining region. The system may include an airflow compression stage having a varying air channel that narrows as the air stream traverses the airflow compression stage to pre-concentrate particles within an interior region of the air stream. The system may include an airflow expansion stage having an air channel that widens to slow the airstream and particle velocities. A portion of the air channel height may be narrowed to allow a larger thermophoretic force to be generated.

Abstract: A resonator comprising a piezoelectric film which creates an acoustic path that is slightly longer in a central region of the resonator than at an edge of the resonator.

Abstract: A method for analyzing particles in an air stream includes concentrating the particles in an interior region of the air stream and deflecting the concentrated particles in the air stream with a generated thermal gradient. Smaller particles in the air stream may be selectively deflected away from the interior region and towards a periphery of the air stream at a different rate than larger particles in the air stream. The generated thermal gradient may be controlled to deflect particles in a selected particle size range onto a surface of a particle detector. An effective mass of the collected particles and an aerosol mass concentration estimate of the particles within the selected particle size range may be generated. Systems for analyzing particles are also disclosed.

Abstract: A system for detecting and analyzing particles in an air stream includes an inlet, a particle concentrator and a particle discriminator having an air channel with a cross-sectional geometry that changes within at least one of the inlet, particle concentrator and particle discriminator. The system may have a sheath air stage including a port for providing sample air, at least one sheath air inlet port for providing sheath air, and a sheath air combining region. The system may include an airflow compression stage having a varying air channel that narrows as the air stream traverses the airflow compression stage to pre-concentrate particles within an interior region of the air stream. The system may include an airflow expansion stage having an air channel that widens to slow the airstream and particle velocities. A portion of the air channel height may be narrowed to allow a larger thermophoretic force to be generated.

Abstract: A system for concentrating particles in an air stream includes an air channel having a first open end and a second open end. The air channel may be enclosed by a channel wall extending from at least the first open to the second open end. Two or more heater elements may be positioned between the first open end and the second open end. The heater elements may be positioned near a periphery of the air channel and cooperatively configured to force particles in the air stream away from the periphery and towards an interior region of the air channel. Particles in the air stream may be thermophoretically forced towards the interior region of the air channel when the heater elements are heated and thermal gradients emanating from the heater elements are generated.

Abstract: A system for analyzing particles in an air stream includes a first heater element configured to deflect particles in an interior region of the air stream towards a peripheral wall of an air channel encompassing the air stream, a second heater element controllable to deflect the particles in a first lateral direction along the peripheral wall, and a third heater element controllable to deflect the particles in a second lateral direction along the peripheral wall. Thermal gradients in the air channel generated by the heater elements may thermophoretically force particles towards the peripheral wall in a direction perpendicular to the air stream to allow thermophoretic forcing and scanning of particles in either the first lateral direction or the second lateral direction along the peripheral wall and onto a surface of a particle detector. Systems and methods for scanning particles with thermophoretic forces are disclosed.

Abstract: A method for analyzing particles includes concentrating the particles in an interior region of an air stream, generating a thermal gradient to deflect the concentrated particles from the interior region of the air stream to a peripheral region of the air stream, receiving orientation information, and adjusting the thermal gradient in response to the received orientation information. The particles may be concentrated in the interior of the air stream with at least two heater elements positioned near a periphery of the air stream and configured to cooperatively force particles away from the periphery and towards the interior region of the air stream. The orientation information may include gravity vector component information or angular rate component information in one, two or three substantially orthogonal directions relative to the air stream. Various systems for airborne particle detection with orientation-dependent particle discrimination are disclosed.