Methods and apparatus for processing fluids are described. In various aspects, a fluid processing system may include a magnetic assembly that includes a plurality of magnetic structures configured to generate a magnetic field gradient within a fluid container. The magnetic structures may be formed as a plurality of electromagnets configured to be individually actuated by a controller. Each of the electromagnets may generate a magnetic field within the fluid container. The electromagnets may be differentially actuated to create a magnetic field gradient within the fluid container to agitate, mix, or otherwise influence magnetic particles disposed within the fluid container. Activation of the electromagnets of an electromagnetic structure may generate a magnetic field gradient that influences magnetic particles in an x-y direction. In addition, activation of the electromagnets of a plurality of electromagnetic structures may generate magnetic field gradients that influences magnetic particles in an x-y direction and z-direction.

In one aspect, a system for dispersing particles in a fluid of a fluid container includes one or more permanent magnets, one or more electric coils, and/or one or more electrodes. The one or more permanent magnets, one or more electric coils, and/or one or more electrodes are configured to disperse the particles in the fluid of the fluid container.

In one aspect, a system for dispersing particles in a fluid of a fluid container includes one or more permanent magnets, one or more electric coils, and/or one or more electrodes. The one or more permanent magnets, one or more electric coils, and/or one or more electrodes are configured to disperse the particles in the fluid of the fluid container.

A method for electromagnetic stirring of liquid metal in a continuous charge electric arc furnace, in which there are positioned a first electromagnetic field along a first axis of electromagnetic stirring and a second electromagnetic field along a second axis of electromagnetic stirring.

A method for electromagnetic stirring of liquid metal in a continuous charge electric arc furnace, in which there are positioned a first electromagnetic field along a first axis of electromagnetic stirring and a second electromagnetic field along a second axis of electromagnetic stirring.

The invention provides a method of circulating magnetically responsive beads within a droplet in a droplet actuator. The invention also provides methods for splitting droplets. The invention, in one embodiment, makes use of a droplet actuator with top and bottom substrates, a plurality of magnetic fields respectively present proximate the top and bottom substrates, wherein at least one of the magnet fields is selectively alterable, and a plurality of droplet operations electrodes positioned along at least one of the top and bottom surfaces. A droplet is positioned between the top and bottom surfaces and at least one of the magnetic fields is selectively altered.

The invention herein relates to conducting assays with an apparatus including a substantially transparent assay cartridge loaded with magnetic beads, and a magnet carrier base positioned below a scanning platform holding the assay cartridge. The assay cartridge includes magnetic beads, sample and control solutions in some wells, and assay reagents in others. A microcomputer controls a stepping motor which controls movement of the magnet carrier base, and causes the magnetic beads to travel from one well to another. An electromagnetic coil-spring assembly induces mixing of well contents with the magnetic beads on actuation. The assay cartridge is authenticated by sending its encoded identifier to a server or website, and assay instructions are provided remotely to the microcomputer. Following assay completion, the cartridge can have color change or other assay indication detected, and the results sent to the server or website or another recipient.

Techniques and apparatus for electromagnetically stirring a melt material are disclosed. In accordance with some embodiments, the system may include a containment vessel within which a melt material may be disposed. The melt material may include, for example, an electrically conductive alloy, which optionally may be non-ferromagnetic and/or glass-forming. In its molten state, the melt material may have alternating current (AC) applied directly thereto while being immersed in a magnetic field, which may be static or dynamic, depending on the desired stirring effect. Application of the AC and magnetic field may continue as the melt material cools and solidifies, the sinusoidal nature of the AC and the Lorentz force of the magnetic field providing convective motion which tends to agitate the molten melt material in a manner which may realize an improvement in heat transfer and chemical homogeneity of the resultant cast solid.

The present disclosure relates to systems and methods for producing emulsions, and more specifically to methods that use ultrasonic rotating magnetic fields for producing emulsions. The systems and/or methods described herein can be used to produce emulsions without the use of surfactant.

The present disclosure relates to systems and methods for producing emulsions, and more specifically to methods that use ultrasonic rotating magnetic fields for producing emulsions. The systems and/or methods described herein can be used to produce emulsions without the use of surfactant.