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Microbial community dynamics at high organic loading rates revealed by pyrosequencing during sugar refinery wastewater treatment in a UASB reactor

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Frontiers of Environmental Science & Engineering 2018年第4期12卷 33-44页

作者： liguo zhang Qiaoying Ban Jianzheng Li College of Environmental and Resource Sciences Shanxi Universily Taiyuan 030000 China State Key Laboratory of Urban Watel Resource and Environment School of Municipal and Environmental Engineering Harbin Institute of Technology Harbin 150000 China＊

The performance and rnicrobial community structure in an upflow anaerobic sludge blanket reactor （UASB） treating sugar refinery wastewater were investigated. The chemical oxygen demand （COD） removal reached above 92.0% at organic loading rates （OLRs） of 12.0-54.0 kgCOD/（m^3· d）. The volatile lhtty acids （VFAs） in effluent were increased to 451.1 mg/L from 147.9 mg/L and the specific methane production rate improved by 1.2 2.2-1bid as the OLR increased. The evolution of microbial comnmnities in anaerobic sludge at three different OLRs was investigated using pyrosequencing. Operational taxonomic units （OTUs） at a 3% distance were 353,337 and 233 for OLRI2, OLR36 and OLR54, respectively. When the OLR was increased to 54.0 kgCOD/（m^3· d） from 12.0 kgCOD/ （m^3· d） by stepwise, the microbial community structure were changed significantly. Five genera （Bacteroides, Trichococcus, Cho,seobacterium, Longilinea and Aerococcus） were the dominant fermentative bacteria at the OLR 12-0 kgCOD/（m^3· d）. However, the sample of OLR36 was dominated by Lacmcoccus, Trichococcus, Anaer-arcus and Veillonella. At the last stage （OLR = 54.0 kgCOD/ （m^3· d）, the diversity and percentage of femlentative bacteria were markedly increased. Apart from fermentative bacteria, an obvious shift was observed in hydrogen-producing acetogens and non- acetotrophic methanogens as OLR increased. Svntrophohacter, Geobacter and Methanomethylovor- ans were the dominant hydrogen-producing acetogens and methylotrophic methanogens in the samples of OLRI2 and OLR36. When the OLR was increased to 54.0 kgCOD/（m^3· d）, the mare hydrogen-producing acetogens and hydrogenotrophic methanogens were substituted with Destd/bvi- brio and Methanospillum. However, the composition of acetotrophic methanogens （Methanosaeta） was relatively stable during the whole operation period of the UASB reactor.

关键词： Upflow anaerobic sludge blanket Sugar refinery wastewater Organic loading rate Pyrosequencing Microbial community structure

Input-to-state stability of coupled hyperbolic PDE-ODE systems via boundary feedback control

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Science China(Information Sciences) 2019年第4期62卷 88-99页

作者： liguo zhang Jianru HAO Junfei QIAO Faculty of Information Technology Beijing University of Technology Key Laboratory of Computational Intelligence and Intelligent Systems

We herein investigate the boundary input-to-state stability(ISS) of a class of coupled hyperbolic partial differential equation-ordinary differential equation(PDE-ODE) systems with respect to the presence of uncertainties and external disturbances. The boundary feedback control of the proportional type acts on the ODE part and indirectly affects the hyperbolic PDE dynamics via the boundary input. Using the strict Lyapunov function, some sufficient conditions in terms of matrix inequalities are obtained for the boundary ISS of the closed-loop hyperbolic PDE-ODE systems. The feedback control laws are designed by combining the line search algorithm and polytopic embedding techniques. The effectiveness of the designed boundary control is assessed by applying it to the system of interconnected continuous stirred tank reactor and a plug flow reactor through a numerical simulation.

关键词： hyperbolic PDE-ODE systems input-to-state stability boundary control Lyapunov function PFR-CSTR models

Mechanical Fault Diagnosis Based on Band-phase-randomized Surrogate Data and Multifractal

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Chinese Journal of Mechanical Engineering 2011年第5期24卷 885-890页

作者： zhang Shuqing ZHAO Yuchun zhang liguo JIN Mei School of Electrical Engineering Yanshan University Qinhuangdao 066004 China

The vibration signals of machinery with various faults often show clear nonlinear ***,fractal dimension analysis as the common useful method for nonlinear signal analysis,is a kind of single fractal form,which only reflects the overall irregularity of signals,but cannot describe its local scaling *** comprehensive revealing of internal properties,a combinatorial method based on band-phase-randomized（BPR） surrogate data and multifractal is *** surrogate data method is effective to eliminate nonlinearity in specified frequency band for a fault signal,which can be utilized to detect nonlinear degree in whole fault signal by nonlinear titration method,and the overall nonlinear distribution of fault signal is displayed in nonlinear characteristic curve that can be used to analyze the fault signal *** multifractal theory as a quantitative analysis method is used to describe geometrical characteristics and local scaling properties,and asymmetry coefficient of multifractal spectrum and multifractal entropy for fault signals are extracted as new criterions to diagnose machinery *** typical faults include rotor misalignment,transversal crack,and static-dynamic rubbing fault are analyzed,and the results indicate that those faults can be distinguished by the proposed method effectively,which provides a qualitative and quantitative analysis way in the field of machinery fault diagnosis.

关键词： fault diagnosis band-phase-randomized surrogate data nonlinear titration multifractal

Recurrent neural network for vehicle dead-reckoning

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Journal of Systems Engineering and Electronics 2008年第2期19卷 351-355页

作者： Ma Haibo zhang liguo Chen Yangzhou School of Electronic Control Engineering Beijing Univ. of Technology Beijing 100022 P. R. China

For vehicle integrated navigation systems, real-time estimating states of the dead reckoning （DR） unit is much more difficult than that of the other measuring sensors under indefinite noises and nonlinear characteristics. Compared with the well known, extended Kalman filter （EKF）, a recurrent neural network is proposed for the solution, which not only improves the location precision and the adaptive ability of resisting disturbances, but also avoids calculating the analytic derivation and Jacobian matrices of the nonlinear system model. To test the performances of the recurrent neural network, these two methods are used to estimate the state of the vehicle＇s DR navigation system. Simulation results show that the recurrent neural network is superior to the EKF and is a more ideal filtering method for vehicle DR navigation.

关键词： dead reckoning extended Kalman filter recurrent neural network vehicle integrated navigationsystems.

A surface-based hiding function linking flume and field data

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Science China(Technological Sciences) 2017年第10期60卷 1560-1569页

作者： zhang liguo FU XuDong DUAN Jennifer G State Key Laboratory of Hydroscience and Engineering Tsinghua University Department of Civil Engineering and Engineering Mechanics University of Arizona

The quantification of the sheltering and exposure effects of non-uniform sediments has been widely achieved through hiding function models. Big challenge exists so far in the model parameter that is highly variable and differs greatly between laboratory flumes and field streams. This paper presents an improved surface-based hiding fimction. The force balance for particle inception was formulated and the allocation of the overall bed shear stress into each group of sediments was mimicked. The new hiding function was examined against and agrees well with the documented field and flume data. It was shown that the hiding fimction is closely related to the relative flow depth and the reference elevation in the velocity profile in addition to the bed material gradation. The power law of velocity profile that applies to both flume flows and natural streams can link the flume and field data together. The hiding function with b = 1/6 and b = 1/2 is applicable to natural streams and laboratory flumes, respectively. The value orb = 0.263 also works well for gravel bed rivers. The range of the reference elevation, namely z0 = 0.4Dm-1.4Dm, is recommended for either the flume or field data. The new hiding function contributes to addressing clearer physical meanings and a useful perspective for further improvement.

关键词： hiding function relative flow depth flume and field data reference elevation

Refill friction stir spot welding of 5083-O aluminum alloy

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Journal of Materials Science & Technology 2018年第5期34卷 878-885页

作者： Zhiwu Xu Zhengwei Li Shude Ji liguo zhang State Key Laboratory of Advanced Welding and Joining Harbin Institute of Technology Faculty of Aerospace Engineering Shenyang Aerospace University

In this work,refill friction stir spot welding（RFSSW） was used to weld 2 mm-thick 5083-O *** Box–Behnken experimental design was used to investigate the effect of welding parameters on the joint lap shear *** showed that a surface indentation of 0.3 mm effectively eliminated the welding *** of the stir zone（SZ） was higher than that of the base material（BM） and the hardness decreased with increasing the heat input during *** optimum failure load of 7.72 k N was obtained when using rotating speed of 2300 rpm,plunge depth of 2.4 mm and refilling time of 3.5 *** fracture modes were obtained during the lap shear test and all were affected by the hook defect.

关键词： Refill friction stir spot welding Keyhole Secondary phases Microhardness Lap shear failure load

Effect of Welding Technologies on Decreasing Welding Residual Stress of Francis Turbine Runner

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Journal of Materials Science & Technology 2010年第10期26卷 951-956页

作者： Shude Ji liguo zhang Xuesong Liu Jianguo Yang School of Aerospace Engineering Shenyang Aerospace University Shenyang 110034 China State Key laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China

On basis of the subsection welding and the local heating s reasonable technological parameters obtained by plane experiment,the welding residual stress field of some Francis turbine runner is regulated and *** the experimental plane with a thickness of 16 mm,the effect of subsection welding on decreasing welding residual stress of the prior welding section is obvious when the distance is less than 50 mm away from the end of latter welding *** the local heating,the best position,where the effect on decreasing the welding residual stress of plane is best,is 60 mm or so away from the edge of heating *** experimental results of runner show that the subsection welding can make the residual compressive stress engender in the blade dangerous area while the stress value is greatly influenced by the length of the welding section of blade *** local heating can further decrease the value of residual stress near blade outlet,while the local heating processed after heat treatment is better than that processed before heat treatment.

关键词： Blade Subsection welding Local heating Welding residual stress

Prediction of Large Structure Welding Residual Stress by Similitude Principles

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Journal of Materials Science & Technology 2009年第6期25卷 861-864页

作者： Shude Ji liguo zhang Xuesong Liu Jianguo Yang School of Aerospace Engineering Shenyang Institute of Aeronautical Engineering Shenyang 110034 China State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China

On basis of the similitude principles, the conception of virtual simulative component and the auxiliary value of welding residual stress, which is deduced by the welding conduction theory, the relation of the welding residual stress between the simulative component and the practical component was attained. In order to verify the correctness of the relation, the investigation was done from the view of the welding experiment and the numerical simulation about the simulative component and the practical component. The results show that the distribution of welding residual stress of the simulative component is the same as that of the practical component. The ratio of welding residual stress attained by the experiment or the simulation method between the practical runner and the simulative component was compared with the ratio obtained by the similitude principles. Moreover, the error is less than 10%. This provides a new idea to predict the welding stress distribution of large practical structure by the contractible physical model, which is important for the welding experiment and the numerical simulation.

关键词： Similitude principles Large welding structure Simulative components Welding residual stress

A New Method of Wind Turbine Bearing Fault Diagnosis Based on Multi-Masking Empirical Mode Decomposition and Fuzzy C-Means Clustering

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Chinese Journal of Mechanical Engineering 2019年第3期32卷 156-167页

作者： Yongtao Hu Shuqing zhang Anqi Jiang liguo zhang Wanlu Jiang Junfeng Li Institute of Electric Engineering Yanshan UniversityQinhuangdao 066004China School of Electrical Engineering and Automation Henan Institute of TechnologyXinxiang 453003China

Based on Multi-Masking Empirical Mode Decomposition (MMEMD) and fuzzy c-means (FCM) clustering, a new method of wind turbine bearing fault diagnosis FCM-MMEMD is proposed, which can determine the fault accurately and timely. First, FCM clustering is employed to classify the data into different clusters, which helps to estimate whether there is a fault and how many fault types there are. If fault signals exist, the fault vibration signals are then demodulated and decomposed into different frequency bands by MMEMD in order to be analyzed further. In order to overcome the mode mixing defect of empirical mode decomposition (EMD), a novel method called MMEMD is proposed. It is an improvement to masking empirical mode decomposition (MEMD). By adding multi-masking signals to the signals to be decomposed in different levels, it can restrain low-frequency components from mixing in highfrequency components effectively in the sifting process and then suppress the mode mixing. It has the advantages of easy implementation and strong ability of suppressing modal mixing. The fault type is determined by Hilbert envelope finally. The results of simulation signal decomposition showed the high performance of MMEMD. Experiments of bearing fault diagnosis in wind turbine bearing fault diagnosis proved the validity and high accuracy of the new method.

关键词： Wind turbine bearing faults diagnosis Multi-masking empirical mode decomposition (MMEMD) Fuzzy c-mean (FCM) clustering