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The preparation of nanoporous nickel films by electrochemical deposition of Ni-Cu alloy followed by the selective anodic etching of the less-active component (Cu) from the alloy was studied in an aqueous solution containing Cu(II) and Ni(II) at room temperature. Constant potential electrodeposition produced columnar Ni-Cu alloys, in which the Ni content increased as the deposition potential became more negative. X-ray diffraction and Auger mapping results indicate the presence of separated Cu-rich and Ni-rich phases in the alloys, with the Cu-rich phase being more concentrated in the middle of the column and surrounded by the Ni-rich phase. Cyclic voltammetric data indicates that anodic dissolution of nickel is retarded by passivation. By taking advantage of nickel passivation, selective anodic etching of copper from the Ni-Cu alloy produces nanohollow nickel tubes on indium-tin-oxide-coated glass substrates. The nanohollow tube structure obtained in this study is different from the interconnected bicontinuous nanopores that are usually obtained by dealloying the less noble component from a homogeneous solid solution alloy. The nanohollow tubes may have resulted from the fact that multiple phases columnar alloy deposits were produced by the electrodeposition step and from the limited mobility of nickel during the anodic etching step.

Most of the effort being expended to revise western water policy concerns the maintenance of instream waters to the exclusion of traditional diversionary interests. Absent from the economics literature is a theoretical treatment addressing the interface between diversionary and instream water uses. At issue is the potential for refining market operations to accomplish efficient allocation in the presence of both diversionary and instream uses. Optimization methods are employed to examine this issue in a highly generalized framework. If a specific structure is adopted, markets and other incentive‐based policies are demonstrated to be capable of efficient water allocation.

The objective of this paper is to provide a more comprehensive efficiency measure to estimate the performance of OECD and non-OECD countries. A Russell directional distance function that appropriately credits the decision-making unit not only for increase in desirable outputs but also for the decrease of undesirable outputs is derived from the proposed weighted Russell directional distance model. The method was applied to a panel of 116 countries from 1992 to 2010. This framework also decomposes the comprehensive efficiency measure into individual input/output components' inefficiency scores that are useful for policy making. The results reveal that the OECD countries perform better than the non-OECD countries in overall, goods, labor and capital efficiencies, but worse in bad and energy efficiencies.