A series of metal-organic frameworks (MOFs) M2 (dobpdc) (M=Mn, Co, Ni, Zn; H4 dobpdc=4,4'-dihydroxy-1,1'-biphenyl-3,3'-dicarboxylic acid), with a highly dense arrangement of open metal sites along hexagonal channels were prepared by microwave-assisted or simple solvothermal reactions. The activated materials were structurally expanded when guest molecules including CO2 were introduced into the pores. The Lewis acidity of the open metal sites varied in the order MnZn, as confirmed by C=O stretching bands in the IR spectra, which are related to the CO2 adsorption enthalpy. DFT calculations revealed that the high CO2 binding affinity of transition-metal-based M2 (dobpdc) is primarily attributable to the favorable charge transfer from CO2 (oxygen lone pair acting as a Lewis base) to the open metal sites (Lewis acid), while electrostatic effects, the underlying factor responsible for the particular order of binding strength observed across different transition metals, also play a role. The framework stability against water coincides with the order of Lewis acidity. In this series of MOFs, the structural stability of Ni2 (dobpdc) is exceptional; it endured in water vapor, liquid water, and in refluxing water for one month, and the solid remained intact on exposure to solutions of pH 2-13. The DFT calculations also support the experimental finding that Ni2 (dobpdc) has higher chemical stability than the other frameworks.

Blowflies, especially species belonging to the subfamily Luciliinae, are the first insects to lay eggs on corpses in Korea. Fast and accurate species identification has been a key task for forensic entomologists. Because conventional morphologic identification methods have many limitations with respect to forensic practice, molecular methods have been proposed to identify fly species of forensic importance. To this end, the authors amplified and sequenced the full length of the cytochrome c oxidase subunit I (COI) gene of the Luciliinae fly species collected in Korea. The results showed the COI sequences are instrumental in identifying Luciliinae fly species. However, when compared with previously reported data, considerable inconsistencies were noted. Hemipyrellia ligurriens data in this study differed significantly from two of the five pre-existing data. Two closely related species, Lucilia illustris and Lucilia caesar, showed an overlap of COI haplotypes due to four European sequences. The results suggest that more individuals from various geographic regions and additive nuclear DNA markers should be analyzed, and morphologic identification keys must be reconfirmed to overcome these inconsistencies.

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Membrane bioreactor (MBR) system has recently become very important in wastewater treatment. However, membrane capacity during the filtration process is reduced by fouling, which is the deposition or adsorption of particles on the membrane surface or inside of the pores. For an efficient operation of MBR system, prediction of MBR fouling progress and determination of proper membrane chemical cleaning interval is necessary. Until now, four blocking models, which are complete blocking, intermediate blocking, cake filtration, and standard blocking, have typically been used to describe and predict the MBR fouling. In this study, a new combined membrane fouling model, based on the four constant flowrate blocking models, is developed to explain the combined effects of the different fouling mechanisms. This model is assumed to be more accurate in determining the chemical cleaning interval by considering variation of dominant fouling mechanisms in the filtration process. The combined fouling model is applied to data sets from a pilot‐scale MBR for monitoring the variations of dominant fouling stage. By checking temporal variations of root mean square error (RMSE) values from fitting trans‐membrane pressure data to four constant flowrate blocking models, the dominant fouling mechanism by each fouling stage is determined. In particular, the fouling prediction result by the new combined model of three fouling mechanisms, which are complete blocking, cake filtration, and intermediate blocking, excluding the standard blocking model has better predictive accuracy than the combined model of four mechanisms, which remarkably reduced the RMSE from 10.48 to 1.73. On the basis of the improvement, the new combined model with three mechanisms has the potential to predict MBR fouling process and to determine the optimum interval for membrane chemical cleaning. Our results would contribute the economic operation of MBR plants by suggesting the appropriate membrane cleaning interval with the filtration capacity maintained at optimal level. Copyright © 2011 Curtin University of Technology and John Wiley & Sons, Ltd.