Abstract: A waveguide structure is described wherein microwaves or radio-frequency waves can be guided in their propagation through channels whose cross-sections contain fractal patterns, with relevant dimensions much smaller than the wavelengths of the guided waves. A finite section of such waveguide can be used as an efficient delay line.

Abstract: Acoustic attenuation materials are described that comprise outer layers of a stiff material sandwiching a relatively soft elastic material therebetween, with means such as spheres, discs or wire mesh being provided within the elastic material for generating local mechanical resonances that function to absorb sound energy at tunable wavelengths.

Abstract: The present invention provides novel configurations for the electrodes in a range of applications for ER fluids. The electrodes are configured so that they generate an electrical field a significant portion of which extends parallel to any anticipated applied force of direction of likely distortion that may act to disrupt the agglomeration of ER particles. By so arranging the electric field to be parallel to such a force there is a strong binding force that acts to counter and tendency for the particles to be disrupted.

Abstract: A “paper look-alike” display comprises pixels formed of dielectric particles suspended in a non-conducting liquid. By applying a voltage to electrodes the particles may be switched between positions in which they are stored in vertical columns normal to the surface of the pixel and have no effect on the color of the pixel, and a position in which they occupy a major part of the surface area of the pixel and influence the color of the pixel accordingly.

Abstract: There is described an electrorheological fluid comprising coated nanoparticle suspended in an electrically insulated hydrophobic liquid. The core particles consist of TiO2 or metal salts of the form M1xM22-2xTiO(C2O4)2 where M1 is selected from the group consisting of Ba, Sr and Ca and wherein M2 is selected from the group consisting of Rb, Li, Na and K. The particle shell is made of highly polar molecules selected from the group consisting of thiourea and urea.

Abstract: There is described an electrorheological fluid comprising coated nanoparticle suspended in an electrically insulated hydrophobic liquid. The core particles consist of TiO2 or metal salts of the form M1xM22-2xTiO(C2O4)2 where M1 is selected from the group consisting of Ba, Sr and Ca and wherein M2 is selected from the group consisting of Rb, Li, Na and K. The particle shell is made of highly polar molecules selected from the group consisting of thiourea and urea.

Abstract: The present invention provides novel configurations for the electrodes in a range of applications for ER fluids. The electrodes are configured so that they generate an electrical field a significant portion of which extends parallel to any anticipated applied force of direction of likely distortion that may act to disrupt the agglomeration of ER particles. By so arranging the electric field to be parallel to such a force there is a strong binding force that acts to counter and tendency for the particles to be disrupted.

Abstract: An electrorheological clutch comprises drive and driven members that selectively engage by the application of a voltage to an electroheological fluid (ER) provided between the driven and driven members. The drive and driven members are formed with axially-oriented surfaces that define between then axially-oriented spaces for the ER fluid so as to minimize problems with settlement of the ER particles.

Abstract: There is disclosed a sound attenuation panel comprising, a rigid frame divided into a plurality of individual cells, a sheet of a flexible material, and a plurality of weights. Each weight is fixed to the sheet of flexible material such that each cell is provided with a respective weight and the frequency of the sound attenuated can be controlled by suitable selecting the mass of the weight.

Abstract: Optically active glazing comprising two parallel plates of glass or the like that define between them a closed volume containing dielectric particles in suspension in a fluid, and electrodes formed on the plates and connected to an electrical power supply for moving and organizing the particles by means of dielectrophoretic forces and of interactions between particles.

Abstract: An electrorheological clutch comprises drive and driven members that selectively engage by the application of a voltage to an electroheological fluid (ER) provided between the driven and driven members. The drive and driven members are formed with axially-oriented surfaces that define between then axially-oriented spaces for the ER fluid so as to minimise problems with settlement of the ER particles.

Abstract: There is described an electrorheological fluid comprising particles of a composite material suspended in an electrically insulating hydrophobic liquid. The composite particles are metal salts of the form M1xM22-2xTiO(C2O4)2 where M1 is selected from the group consisting of Ba, Sr and Ca and wherein M2 is selected from the group consisting of Rb, Li, Na and K, and the composite particles further include a promoter selected from the group consisting of urea, butyramide and acetamide.

Abstract: A “paper look-alike” display comprises pixels formed of dielectric particles suspended in a non-conducting liquid. By applying a voltage to electrodes the particles may be switched between positions in which they are stored in vertical columns normal to the surface of the pixel and have no effect on the colour of the pixel, and a position in which they occupy a major part of the surface area of the pixel and influence the colour of the pixel accordingly.

Abstract: Acoustic attenuation materials are described that comprise outer layers of a stiff material sandwiching a relatively soft elastic material therebetween, with means such as spheres, discs or wire mesh being provided within the elastic material for generating local mechanical resonances that function to absorb sound energy at tunable wavelengths.

Abstract: There is disclosed an electromagnetic relay comprising a stationary first member and a second member adapted to move towards and away from the first member such that when the second member move towards the first member an electrical contact is closed. Spring means biases the members apart, and permanent magnet means are provided for generating a force of attraction between the members, and selectively operable means is provided for generating an electromagnetic force. The permanent magnet means has a strength such that when the first and second members are apart the permanent magnet means is insufficient to overcome the spring means, but when the members are brought together the permanent magnet means is able to hold the members together against the spring means.

Abstract: The present invention relates to planar materials having bandgap properties. The materials are formed by depositing conductive fractal patterns on a non-conducting substrate. The bandgap location(s) are defined by parameters including the number of fractal levels, and the dimension of the fractal mother element. The bandgaps can also be actively controlled by injecting current into the conducting pattern.

Abstract: There is described an electrorheological fluid comprising particles of a composite material suspended in an electrically insulating hydrophobic liquid. The composite particles are metal salts of the form M1xM22-2xTiO(C2O4)2 where M1 is selected from the group consisting of Ba, Sr and Ca and wherein M2 is selected from the group consisting of Rb, Li, Na and K, and the composite particles further include a promoter selected from the group consisting of urea, butyramide and acetamide.

Abstract: This invention provides a composite material having a matrix of structural material containing embedded zones of soft elastic material and zones of solid relatively high density material within the soft elastic material. By selecting a particular resonance frequency for the subunits of soft elastic material and solid high density material, frequencies just lower than the resonance frequencies will be unable to propagate through the material and be strongly reflected or absorbed. Such material may be used in the manufacture of filters or shields against particular target frequencies. Subunits having a variety of resonance frequencies may provide a broader range of frequencies that the material may shield.

Abstract: The present invention relates to planar materials having bandgap properties. The materials are formed by depositing conductive fractal patterns on a non-conducting substrate. The bandgap location(s) are defined by parameters including the number of fractal levels, and the dimension of the fractal mother element. The bandgaps can also be actively controlled by injecting current into the conducting pattern.

Abstract: Acoustic attenuation materials are described that comprise outer layers of a stiff material sandwiching a relatively soft elastic material therebetween, with means such as spheres, discs or wire mesh being provided within the elastic material for generating local mechanical resonances that function to absorb sound energy at tunable wavelengths.