Abstract: A method for selective dissolution of tin and/or lead- or tin-containing alloys from printed circuit boards is provided comprising contacting a printed circuit board with a solution comprising Ti(IV) and an acid which forms stable and soluble salt of Ti(III), Ti(IV), Sn(II) and Pb(II), under conditions to effect dissolution of substantially all of the Sn and/or Pb- or Sn-containing alloy therefrom, as Sn(II) and/or Pb(II) and recovering from the solution by electrolytic reduction substantially all of the Sn(II) and/or PB(II) species as Sn and/or Pb. After the electrolytic reduction step, the oxidant metal species is regenerated by oxidation and recycled to the first stage of the process.

Abstract: A process for the preparation of an anisotropic conducting material including the steps of providing a strip or sheet of a non-conducting matrix and laminating at least one layer of a release material to each side thereof to form a composite matrix, forming an array of holes in a predetermined pattern in the composite matrix, passing the matrix through a coating head which simultaneously fills the holes in the array in the composite matrix from both sides of the matrix with a conducting material, curing or drying the composite filled matrix and removing at least one layer of release material from each side of the matrix.

Abstract: A method of forming a multipole magnet wherein two backing sheets of paper or film material are screen or stencil printed with an ink containing magnetic particles and a carrier material to provide respective complementary patterned areas thereon, the patterned areas of ink are cured or dried, the respective ink patterns are magnetized using a magnetic field perpendicular to a plane of the backing sheets, and the sheets are combined into a laminate wherein the patterned areas are located between the two sheets.

Abstract: A solid electrolyte sensor to measuring the amount of trace elements, such as sulfur, in molten metals such as steel is provided wherein zirconia toughened strontium .beta.-alumina is used as the solid electrolyte. The resulting sensor is highly resistant to thermal shock, and is suitable for use with molten metals at temperatures of 1350.degree. C. or higher.

Abstract: A device sensitive to pressure waves including first and second sheets of polyvinylidene fluoride supported in spaced apart relationship. The major faces of each sheet are provided with respective inner and outer foils of copper and an electrically insulating sheet of PTFE is sandwiched between, and bonded to, the inner foils. The first and second sheets are poled in a direction normal to their respective major surfaces so as to be more sensitive to pressures waves incident thereon, along said normal direction, than to pressure waves incident thereon along other directions. The inner electrically conductive sheets are electrically connected together and a voltage sensor is used to detect voltages, developed across the major surfaces of the first and second sheets and indicative of pressure waves incident thereon.

Abstract: A record having an information track cut into the surface and a visible pattern formed on surface "lands" bordering the track. The pattern is shallower than the track depth, typically 0.7 micron for a 25 micron sound microgroove record track. A method of providing the marking by applying solvent to a lacquer before cutting a master is described.

Abstract: A modulated groove record, such as a video disc, has a coating on a conductive layer bearing the modulated groove formed from the material of the layer. The material may be aluminium and the coating may be a uniform dielectric of aluminium oxide formed by anodizing. The groove may be impressed in the aluminium surface by applying a matrix to an aluminium/plastics laminate forcefully and rapidly so that the aluminium yields while the plastic appears rigid. The aluminum layer thickness is at least twenty times the depth of the groove.