Acknowledgments
This study was supported by the National Natural Science
Foundation of China (Grant No. 51078161) and Special Fund for
the Wuhan National Science and Technology Pillar Program (Grant
No. 201051824577).
Appendix A. Supplementary material
Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.wasman.2014.
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