A microfluidic device includes: a microchannel defining a flow path; a Brownian motor structure comprising two or more sorting channels having distinct ratchet topographies, the Brownian motor structure in fluid communication with the microchannel; and a filter extending transversely to the microchannel, the filter configured to filter particles, subject to sizes thereof, in a liquid advancing along the flow path, whereby smaller particles of the liquid can pass downstream of the filter in the flow path, and larger particles of the liquid are directed to the Brownian motor structure to be sorted out according to sizes thereof via the sorting channels.

Acoustic perfusion devices for separating biological cells from other material in a fluid medium are disclosed. The devices include an inlet port, an outlet port, and a collection port that are connected to an acoustic chamber. An ultrasonic transducer creates an acoustic standing wave in the acoustic chamber that permits a continuous flow of fluid to be recovered through the collection port while keeping the biological cells within the acoustic chamber to be returned to the bioreactor from which the fluid medium is being drawn.

In one embodiment, a dust collecting apparatus includes a container configured to contain a fluid that includes particles to be collected. The apparatus further includes one or more sound sources configured to generate, in the container, a standing sound wave including at least one node to trap the particles in a vicinity of the node. The one or more sound sources are configured to generate the standing sound wave so that the node does not contact a wall face of the container or contacts a predetermined portion of the wall face of the container. The predetermined portion is formed of a member that prevents the particles from leaving from the node located in a vicinity of the predetermined portion.

In one embodiment, a dust collecting apparatus includes a container configured to contain a fluid that includes particles to be collected. The apparatus further includes one or more sound sources configured to generate, in the container, a standing sound wave including at least one node to trap the particles in a vicinity of the node. The one or more sound sources are configured to generate the standing sound wave so that the node does not contact a wall face of the container or contacts a predetermined portion of the wall face of the container. The predetermined portion is formed of a member that prevents the particles from leaving from the node located in a vicinity of the predetermined portion.

A fluid device includes: a flow path through which a fluid flows; a pressure chamber spaced apart from the flow path in a first direction (Y direction) orthogonal to a flowing direction of the fluid in the flow path; a communication path that is formed along the Y direction and that communicates the flow path with the pressure chamber; and an ultrasonic wave transmitter configured to transmit ultrasonic waves to the fluid in the pressure chamber to generate a standing wave along the Y direction in the flow path.

Separation of particles or droplets from a host fluid may be achieved using a transducer and/or reflector that is a thin, non-planar structure. The thin non-planar structure improves operation of an acoustic standing wave generated by an acoustic transducer. The structure may operate as a pressure release boundary and may be constructed as plastic film.

Initial liquid containing fine bubbles is produced by mixing water and air (step S11). Fine bubbles have diameters of less than 1 μm. The density of bubbles in the initial liquid is measured (step S13), and when the measured density is less than a target density (step S14), the initial liquid is heated and reduced in pressure so that the liquid is vaporized (step S15). As a volume of the liquid decreases, the density of fine bubbles increases, and high-density fine bubble-containing liquid is easily obtained. Alternatively, by increasing the density of fine bubbles in the initial liquid with using a filter that does not pass all fine bubbles, high-density fine bubble-containing liquid is easily acquired (step S15). When the density of bubbles in the initial liquid is greater than the target density, the initial liquid is diluted (step S16).

Initial liquid containing fine bubbles is produced by mixing water and air (step S11). Fine bubbles have diameters of less than 1 μm. The density of bubbles in the initial liquid is measured (step S13), and when the measured density is less than a target density (step S14), the initial liquid is heated and reduced in pressure so that the liquid is vaporized (step S15). As a volume of the liquid decreases, the density of fine bubbles increases, and high-density fine bubble-containing liquid is easily obtained. Alternatively, by increasing the density of fine bubbles in the initial liquid with using a filter that does not pass all fine bubbles, high-density fine bubble-containing liquid is easily acquired (step S15). When the density of bubbles in the initial liquid is greater than the target density, the initial liquid is diluted (step S16).

A method of recovering filler material from a polymer material comprises (a) heating the polymer material to a first temperature; (b) heating the polymer material to a second temperature higher than the first temperature resulting in a pyrolyzed material; (c) elutriating the pyrolyzed material to obtain a separated mixture; and (d) filtering the separated mixture to obtain the filler material.

A method of recovering filler material from a polymer material comprises (a) heating the polymer material to a first temperature; (b) heating the polymer material to a second temperature higher than the first temperature resulting in a pyrolyzed material; (c) elutriating the pyrolyzed material to obtain a separated mixture; and (d) filtering the separated mixture to obtain the filler material.