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2022 1

2007 1

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Pentachlorophenol (PCP) degradation microorganism community structure under microaeration condition

Chen Yuancai, Hao Yuan, Fu Shiyu, Zhan Huaiyu

《化学科学与工程前沿（英文）》 2007年第1卷第4期页码 411-415 doi: 10.1007/s11705-007-0075-8

摘要： The comparison of pentachlorophenol (PCP) degradation was conducted under micro-aeration and anaerobic condition with three series of batch experiment, results of which indicated that during micro-aeration condition co-immobilized of anaerobic granular sludge and isolated aerobic bacterial species could enhance the efficiency of PCP reduction through the synergism of aerobes and anaerobes reductive dechlorination and exchange of metabolites within the co-immobilized granular sludge. While during anaerobic condition, there was no great difference in the three series. The specific activities experiment further confirmed that strict anaerobes were not affected over the presence of micro aeration environment. Microorganism community construction of co-immobilized anaerobic granular sludge and the mixed isolated aerobic community was also deduced. By the efficient cooperation of aerobes and anaerobes, the high efficiency removal rate of PCP was implemented.

关键词： comparison co-immobilized anaerobic anaerobic granular exchange PCP

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Effect of undercut on the lower bound stability of vertical rock escarpment using finite element and power cone programming

Shuvankar DAS; Debarghya CHAKRABORTY

《结构与土木工程前沿（英文）》 2022年第16卷第8期页码 1040-1055 doi: 10.1007/s11709-022-0841-1

摘要： In the present study, the stability of a vertical rock escarpment is determined by considering the influence of undercut. Lower bound finite element limit analysis in association with Power Cone Programming (PCP) is applied to incorporate the failure of rock mass with the help of the Generalized Hoek-Brown yield criterion. The change in stability due to the presence of undercut is expressed in terms of a non-dimensional stability number (σ_ci/γH). The variations of the magnitude of σ_ci/γH are presented as design charts by considering the different magnitudes of undercut offset (H/v_u and w_u/v_u) from the vertical edge and different magnitudes of Hoek-Brown rock mass strength parameters (Geological Strength Index (GSI), rock parameter (m_i,), Disturbance factor (D)). The obtained results indicate that undercut can cause a severe stability problem in rock mass having poor strength. With the help of regression analysis of the computed results, a simplified design equation is proposed for obtaining σ_ci/γH. By performing sensitivity analysis for an undisturbed vertical rock escarpment, we have found that the undercut height ratio (H/v_u) is the most sensitive parameter followed by GSI, undercut shape ratio (w_u/v_u), and m_i. The developed design equation as well as design charts can be useful for practicing engineers to determine the stability of the vertical rock escarpment in the presence of undercut. Failure patterns are also presented to understand type of failure and extent of plastic state during collapse.

关键词： undercut vertical escarpment stability Hoek-Brown yield criterion PCP