A method of controlling the electrical properties of a quantity of magnetite particles comprises the step of oxidising at least some of the quantity of magnetite particles by heating the said quantity of magnetite particles in an oxygen rich environment for a period of time.

Composite Materials A composite material responsive to mechanical and/or electrical stress comprises at least one substantially non-conductive binder and at least a first electrically conductive filler. The conductivity of the composite material in an unstressed state is related to the conductivity of the at least one substantially non-conductive binder and in a stressed state to the conductivity resulting from the presence of the at least first electrically conductive filler in the composition. The first electrically conductive filler is comprised of magnetite particles in a particle size distribution, and the at least one binder may include an oil, a gel, a wax a gel-wax, gel-ink or mixtures thereof.

An electromechanical sensor includes: an elastic carrier arranged to extend when subjected to an external mechanical load; a sensing sheath arranged at least partially around and along the elastic carrier; wherein the sensing sheath includes an electrically resistive element having a first electrical resistance operable to change upon a change of a dimension of the elastic carrier.

Provided is a pressure-strain sensor including a graphene structure having a three-dimensional porous structure, planar sheets provided on a surface of the graphene structure, and a polymer layer configured to cover the graphene structure and the planar sheets, wherein each of the planar sheets contains a transition metal chalcogenide compound.

A method of agglomerating nanoparticles to form larger agglomerates is shown. The nanoparticles are mixed with a resin to form a first mixture (803) of agglomerates, having sizes over a range that includes agglomerates considered to be too large, suspended in the resin. A bead milling cylinder (802) produces a second mixture (808) with fewer large agglomerates. A filter (1001) removes the remaining large agglomerates. The resulting mill base is cut with a solvent before deployment.

A force sensitive resistor includes first and second electrical contacts, and a layer of deformable material impregnated with carbon nanotubes. The layer of deformable material is arranged between the first and second electrical contacts. A difference in the conductivity of the impregnated material caused by deformation of the material is detectable across the contacts. A method of manufacturing a force sensitive resistor includes the steps of providing first and second electrical contacts, and arranging a deformable material impregnated with carbon nanotubes between the first and second electrical contacts. Again, a difference in the conductivity of the impregnated material caused by deformation of the material is detectable across the contacts.

A strain gauge includes a flexible substrate, and resistors each formed of a Cr composite film. The resistors include a first resistor formed on one side of the substrate and includes a second resistor formed on another side of the substrate. The first resistor and the second resistor are arranged such that grid directions of the first resistor and the second resistor intersect in a plan view.

A strain gauge includes a flexible substrate, and resistors each formed of a Cr composite film. The resistors include a first resistor formed on one side of the substrate and includes a second resistor formed on another side of the substrate. The first resistor and the second resistor are arranged such that grid directions of the first resistor and the second resistor intersect in a plan view.

A pressure sensitive electrically conductive composition comprises a contained quantity of magnetite particles, wherein the quantity of magnetite particles includes a distribution of particle sizes between sub-micron and tens of microns, and wherein the magnetite particles have a plurality of planar faces, adjacent planar faces connected at a vertex, the particles each having a plurality of vertices wherein the magnetite particles are irregular in shape and have a low aspect ratio.

A method includes coating at least one conductive element of an electronic device with an electrically non-conductive thixotropic liquid. An electronic device includes a first layer including an upper conductive element, a second layer including a lower conductive element, and a spacer positioned between the layers. The first layer, the second layer, and the spacer define a sensing chamber in which the upper and lower conductive elements move to vary the resistance of the electronic device. A non-conductive thixotropic liquid is present within the sensing chamber. Movement of the layers toward each other displaces the thixotropic liquid from an initial state coating at least one of the conductive elements to permit contact between the conductive elements, and movement of the first layer and the second layer away from each other returns the thixotropic liquid to the initial state.