The invention is directed to a method and a system for producing a ferrofluid comprising providing a stock solution with Fe(II) and Fe(III); mixing the stock solution with a base to form magnetic nanoparticles and a spent solution, said method further comprising a separation step of separating the nanoparticles from the spent solution by applying a magnet to immobilize the nanoparticles and remove at least part of the spent solution as supernatant from the immobilized nanoparticles. In another aspect, the invention is directed to the resulting ferrofluid.

The methods of the invention employ targeted magnetic particles, preferably targeted nanomagnetic particles, and targeted buoyant particles such as buoyant microparticles and microbubbles. Among the benefits of the invention is the ability to combine targeted magnetic particles with differentially targeted buoyant particles to achieve separation of two or more specifically cell targeted populations during the same work flow.

The methods of the invention employ targeted magnetic particles, preferably targeted nanomagnetic particles, and targeted buoyant particles such as buoyant microparticles and microbubbles. Among the benefits of the invention is the ability to combine targeted magnetic particles with differentially targeted buoyant particles to achieve separation of two or more specifically cell targeted populations during the same work flow.

Disclosed are methods for identifying desired members from a display libraries, including bacteriophage display libraries. Display library members can be amplified in the presence of a target compound so that cycles of selection can be rapidly completed.

A method of operating a magnetic selector is provided. The magnetic selector includes a housing including a floor having a floor surface, a magnet carrier disposed on an opposite side of the floor from the floor surface and having at least one magnet disposed thereon, the magnet carrier being moveable relative to the floor between a first state wherein the magnet carrier is adjacent the floor and a second state wherein the magnet carrier is spaced from the floor. The method includes disposing a container on the floor surface, moving the magnet carrier to the first state to apply a magnetic field to a fluid in the container, moving the magnet carrier to the second state from the first state to disengage the magnetic field from the container, and removing the container.

There is provided a means capable of recovering a valuable material such as cobalt and nickel, with a low grade of a metal derived from a negative electrode current collector, a low grade of fluorine, and a low grade of a material derived from a negative electrode active material. A method for recovering a valuable material from a lithium ion secondary battery, is characterized in that it includes: a heat treatment step of performing heat treatment on a lithium ion secondary battery; a crushing step of crushing a heat-treated object obtained through the heat treatment step; a classification step of classifying a crushed object obtained through the crushing step into a coarse particle product and a fine particle product; and a wet magnetic separation step of performing wet magnetic separation on the fine particle product obtained through the classification step.

There is provided a means capable of recovering a valuable material such as cobalt and nickel, with a low grade of a metal derived from a negative electrode current collector, a low grade of fluorine, and a low grade of a material derived from a negative electrode active material. A method for recovering a valuable material from a lithium ion secondary battery, is characterized in that it includes: a heat treatment step of performing heat treatment on a lithium ion secondary battery; a crushing step of crushing a heat-treated object obtained through the heat treatment step; a classification step of classifying a crushed object obtained through the crushing step into a coarse particle product and a fine particle product; and a wet magnetic separation step of performing wet magnetic separation on the fine particle product obtained through the classification step.

There is provided a method of extracting material from a fluid method of extracting material from a fluid, the fluid being held within a fluid chamber. The method comprises drawing, with a magnetic field generating system, at least one magnetically susceptible member through the fluid around a closed path between at least three points in the chamber, said at least one member being adapted to bind to material in fluid in the chamber. The at least three points are arranged relative to each other in a shape having at least two dimensions, the magnetic field generating system being configured to move the at least on magnetically susceptible member directly between the at least three points, material in the fluid binding to the at least one magnetically susceptible member when it comes into contact with the at least one member as it moves through the fluid.

Methods are provided for separating magnetically responsive beads from a droplet in a droplet actuator. Droplet operations electrodes and a magnet are arranged in a droplet actuator to manipulate a bead-containing droplet and position it relative to a magnetic field region that attracts the magnetically responsive beads. The droplet operations electrodes are operated to control the droplet shape and transport it away from the magnetic field region to form a concentration of beads in the droplet. The continued transport of the droplet away from the magnetic field causes the concentration of beads to break away from the droplet to yield a small, concentrated bead-containing droplet immobilized by the magnet.

A magnetic-field generator (10) is provided to be used in construction of a cell sheet (12), and include s a magnetic circuit assembly (24) configured to generate a magnetic field for the construction of the cell sheet (12) using magnetic force caused by the magnetic field wherein the magnetic force is substantially transverse to a plane defined by the cell sheet (12), and a power control system (44) configured to generate and control electric power to magnetically charge the magnetic circuit assembly (24) using the electric power.