A double exhaust pipe for an engine includes an inner pipe shell, and an outer pipe shell in which the inner pipe shell is accommodated. The system can include two or more differing XPath generators, at least one of the XPath generators producing at least two XPath expressions for a selected node, the produced XPath expressions forming a redundant set of robust XPath expressions configured to identify the selected node. The method also includes receiving, by the second device, the requested information from the first device, including the item allowing the information provision. The product provider is able to liquidate the product and obtain payment equivalent to what it would otherwise have obtained in a prior art liquidation process, auction or trading environment. The stack pusher has a variable position within a range of motion wherein such position is dependent upon a quantity of sheets in the stack. The D-mannitol shows improved compressibility and is useful as an excipient.