Abstract: Method of assembling a first thin copper part and a second thin aluminum part, each to be welded using heterogeneous welding, includes placing the ends of the parts so that they face one another and pressing the ends against one another so as to constitute a welding zone extending therebetween; and applying an aluminum alloy by way of filler metal to the welding zone using a low energy welding method in which the electric arc and the meltable filler wire are wider than the combined thickness of the parts, the parts being held so as to maintain the welding zone at the top using a fixing element including at least two rigid blocks of a conductive material whose thickness is between 1 and 2 mm, whose length is greater than that of the parts and whose width is sufficient to hold the parts, and a pressure fixing system.

Abstract: Method of assembling a first thin copper part and a second thin aluminum part, each to be welded using heterogeneous welding, includes placing the ends of the parts so that they face one another and pressing the ends against one another so as to constitute a welding zone extending therebetween; and applying an aluminum alloy by way of filler metal to the welding zone using a low energy welding method in which the electric arc and the meltable filler wire are wider than the combined thickness of the parts, the parts being held so as to maintain the welding zone at the top using a fixing element including at least two rigid blocks of a conductive material whose thickness is between 1 and 2 mm, whose length is greater than that of the parts and whose width is sufficient to hold the parts, and a pressure fixing system.

Abstract: A membrane purification system and method are described in which a first membrane, an osmotically active agent, and a second membrane are utilized to separate fluid components. In general, fluid is moved through the first membrane into an osmosis compartment containing the osmotically active agent by the osmotic force of an osmotically active agent disposed between the first membrane and the second membrane. The fluid is forced from the osmotically active agent and through the second membrane while the second membrane retains the osmotically active agent in the osmosis compartment. The osmotically active agent may include a polymer.

Abstract: A process for the direct synthesis of high surface area amorphous chalcogenides of transition metals of Group IV, V, VI and VII elements, comprising the steps of:(1) forming a mixture of:(a) a halide of a said transition metal having the formula MY.sub.n where Y is chlorine, bromine, flurorine, or iodine, and n is 3, 4, 5 or 6, and(b) a source of chalcogen selected from compounds having the formula (R).sub.3 Si--X--Si(R).sub.3 wherein R is alkyl having from 1-4 carbon atoms and X is sulfur, selenium or tellurium,(2) reacting said mixture at a temperature of -77.degree. C. to +160.degree. C.;(3) separating the transition metal chalcogenide from the reaction mixture; and(4) washing said chalcogenide with an inert solvent to remove unreacted materials and the byproducts of the reaction.The high surface area amorphous chalcogenides prepared according to the covalent exchange process of the invention are advantageously used in primary or secondary batteries, particularly lithium cells.