Abstract: A panel audio loudspeaker having a panel extends in a plane and an actuator is coupled to the panel. The actuator includes a voice coil attached to and extending from the panel along an axis, a magnet assembly suspended from the panel via one or more springs, and a temperature sensor in electrical contact with the coil at three different axial locations. The temperature sensor is configured, during operation of the device, to measure a temperature of the coil based on voltage measurements at the three different axial locations.

Abstract: The present invention provides a modular Christmas tree (10) comprising three or more sides (12) that rise from a floor to give the tree a tapering shape, and central support structures (14b) that extend outwardly to support the sides. Each side (12) comprises elongate pieces (16a-c) joined together with connectors that allow the series of elongate pieces to be separated for storage of the disassembled Christmas tree. Each central support structures includes a hub that supports each side, and may also comprise spokes that extend from the hub to each side. The hubs, spokes and sides are joined by connectors that allow the tree to be disassembled for storage.

Abstract: An unmanned vehicle (20) for relaying radio frequency signals in a tactical communications network is described. The unmanned vehicle comprises a processor (22) arranged to receive the location of a first asset (40a); select a relay site (30) from at least one relay site; and control the unmanned vehicle to move to the selected relay site, wherein at the selected relay site, communication between the first asset and the unmanned vehicle is enabled. The unmanned vehicle also comprises a receiver for receiving data from the first asset; and a transmitter for transmitting the data to a second asset (40b, 20, 10). A control unit (60) for an unmanned vehicle, a tactical communications network comprising a plurality of unmanned vehicles, and a method of relaying signals in a tactical communications network using an unmanned vehicle are all also described.

Abstract: A panel audio loudspeaker includes a panel and an actuator attached to a surface of the panel and configured to cause vibration of the panel. The actuator comprises a magnetic coil in thermal communication with the panel. The panel audio loudspeaker further comprises a plurality of electrical sensors electrically coupled to the magnetic coil and configured to output time-varying electrical data for the magnetic coil, and an electronic control module in communication with the magnetic coil and the electrical sensors. The electronic control module is configured to perform operations comprising: providing a current to the magnetic coil; receiving the time-varying electrical data for the magnetic coil; determining an electrical energy provided to the magnetic coil between a first time and a second time; accessing a thermal model of the panel; and determining a change in a panel temperature between the first time and the second time.

Abstract: A panel audio loudspeaker having a panel extends in a plane and an actuator is coupled to the panel. The actuator includes a voice coil attached to and extending from the panel along an axis, a magnet assembly suspended from the panel via one or more springs, and a temperature sensor in electrical contact with the coil at three different axial locations. The temperature sensor is configured, during operation of the device, to measure a temperature of the coil based on voltage measurements at the three different axial locations.

Abstract: An actuator includes a voice coil and a moving magnet assembly. The coil is attached to a panel extending in a plane. A first portion of the coil includes a first set of windings arranged in a spiral extending parallel to the plane. The first set of windings spans a first dimension in a first direction parallel to the plane. The first set of windings is attached to the panel. A second portion of the coil includes a second set of windings extending perpendicular to the plane. The second set of windings spans a second dimension in the first direction. The first dimension is larger than the second dimension. The magnet assembly is suspended from the panel, and includes a magnet positioned within the second portion of the coil. The magnet assembly is configured to vibrate in a second direction perpendicular to the plane during operation of the actuator.

Abstract: The present invention provides a modular Christmas tree (10) comprising three or more sides (12) that rise from a floor to give the tree a tapering shape, and central support structures (14b) that extend outwardly to support the sides. Each side (12) comprises elongate pieces (16a-c) joined together with connectors that allow the series of elongate pieces to be separated for storage of the disassembled Christmas tree. Each central support structures includes a hub that supports each side, and may also comprise spokes that extend from the hub to each side. The hubs, spokes and sides are joined by connectors that allow the tree to be disassembled for storage.

Abstract: In general, the subject matter described in this disclosure can be embodied in methods, systems, and program products for detecting, by a computing system, that user input has contacted or is about to contact transparent material at a location of a depression in a planar surface of the transparent material. The computing system vibrates, in response to the computing system detecting that the user input has contacted or is about to contact the transparent material at the location of the depression, the transparent material at the location of the depression using one or more transducers. The computing system ceases the vibration of the transparent material at the location of the depression in response to the computing system determining that criteria for ceasing the vibration has been satisfied.

Abstract: In general, the subject matter described in this disclosure can be embodied in methods, systems, and program products for detecting, by a computing system, that user input has contacted or is about to contact transparent material at a location of a depression in a planar surface of the transparent material. The computing system vibrates, in response to the computing system detecting that the user input has contacted or is about to contact the transparent material at the location of the depression, the transparent material at the location of the depression using one or more transducers. The computing system ceases the vibration of the transparent material at the location of the depression in response to the computing system determining that criteria for ceasing the vibration has been satisfied.

Abstract: The invention provides a process for the preparation of alumina gels possessing a high alumina content, namely from 10% to 16%. The gels are useful in the production of antacid preparations. The gels are prepared by admixing a solid aluminium sulphate with an aqueous solution of a carbonate and bicarbonate, thickening the precipitated gel, washing and thickening the gel again.