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Nitrous oxide emission by denitrifying phosphorus removal culture using polyhydroxyalkanoates as carbon source

Journal of Environmental Sciences 2012年第9期24卷 1616-1623页

作者： Yan zhou Melvin Lim Soekendro Harjono Wun Jern ng Advanced Environmental Biotechnology Center (AEBC-NEWRI) 60 Nanyang Avenue North Wing Level B2 Room O1 Nanyang Technological University 639798 Singapore Keppel Environmental Technology Centre Pte Ltd. 61 Old Toh Tuck Road 597656 Singapore Division of Environmental and Water Resources Engineering School of Civil and Environmental Engineering Nanyang Technological University 639798 Singapore

Nitrous oxide （N2O） emission has been reported to be enhanced during denitrification when internally-stored compounds are used as carbon sources. However, negligible N2O emissions have been detected in the few studies where polyhydroxyalkanoates （PHA） were specifically used. This study investigated and compared the potential enhancement of N2O production, based on utilization of an internally-stored polymer and external carbon （acetate） by a denitrifying phosphorus removal culture. Results indicated that at relatively low chemical oxygen demand-to-nitrogen （COD/N） ratios, more nitrite was reduced to N2O in the presence of an external carbon source as compared to an internal carbon source （PHA）. At relatively higher COD/N ratios, similar N2O reduction rates were obtained in all cases regardless of the type of carbon source available. N2O reduction rates were, however, generally higher in the presence of an internal carbon source. Results from the study imply that when the presence of an external carbon source is not sufficient to support denitrification, it is likely competitively utilized by different metabolic pathways of denitrifying polyphosphate accumulating organisms （DPAOs） and other ordinary denitfifiers. This study also reveals that the consumption of PHA is potentially the rate-limiting step for N2O reduction during denitrification.

关键词： N2O denitrification carbon source enhanced biological phosphorus removal DPAOs PHA

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Eco-geotechnics for human sustainability

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Science China(Technological Sciences) 2022年第12期65卷 2809-2845页

作者： ng Charles Wang Wai ZHAng Qi zhou Chao NI JunJun Department of Civil and Environmental Engineering The Hong Kong University of Science and TechnologyHong Kong 999077China Department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityHong Kong 999077China School of Transportation Southeast UniversityNanjing 211189China

As a result of climate change and increasing engineering activities, soil-related disasters such as slope failures and sandstorms have become more frequent worldwide. These disasters have caused not only loss of life, but also have led to serious economic losses as well as ecological and environmental damage. To sustain mankind, a new discipline, eco-geotechnics, has rapidly become established and developed in recent years. It integrates scientific knowledge from soil mechanics, rock mechanics,ecology, biology, and atmospheric science to develop cross-disciplinary theories and carry out experiments to tackle grand world challenges such as the effects of climate change. Through the development of eco-geotechnics, various eco-friendly technologies have been developed to mitigate sandstorms and to improve the performance of earthen structures such as embankments, slopes and landfill covers. This state-of-the-art review introduces and discusses the important advances in the field of eco-geotechnics,covering theoretical developments, laboratory testing, centrifuge modelling, field monitoring and engineering ***, the research gaps and future needs of eco-geotechnics are highlighted and discussed.

关键词： sustainability eco-geotechnics atmosphere-plant-soil interactions ecology unsaturated soil mechanics

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Impact of undissociated volatile fatty acids on acidogenesis in a two-phase anaerobic system

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Journal of Environmental Sciences 2016年第4期28卷 196-201页

作者： Keke Xiao Yan zhou Chenghong Guo Yogananda Maspolim Wun Jern ng Advanced Environmental Biotechnology Centre Nanyang Environment and Water Research InstituteNanyang Technological University School of Civil and Environmental Engineering Nanyang Technological University

This study investigated the degradation and production of volatile fatty acids（VFAs）in the acidogenic phase reactor of a two-phase anaerobic system.20 mmol/L bromoethanesulfonic acid（BESA）was used to inhibit acidogenic methanogens（which were present in the acidogenic phase reactor）from degrading *** impact of undissociated volatile fatty acids（un VFAs）on＂net＂VFAs production in the acidogenic phase reactor was then evaluated,with the exclusion of concurrent VFAs degradation.＂Net＂VFAs production from glucose degradation was partially inhibited at high un VFAs concentrations,with 59%,37% and 60% reduction in production rates at 2190 mg chemical oxygen demand（COD）/L undissociated acetic acid（un HAc）,2130 mg COD/L undissociated propionic acid（un HPr）and 2280 mg COD/L undissociated n-butyric acid（un HBu）,*** profile of VFAs produced further indicated that while an un VFA can primarily affect its own formation,there were also un VFAs that affected the formation of other VFAs.

关键词： Anaerobic process Waste treatment Substrate inhibition Undissociated volatile fatty acids Acidogenesis

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Reconstructing shock front of unstable detonations based on multi-layer perceptron

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Acta Mechanica Sinica 2021年第11期37卷 1610-1623,I0001页

作者： Lin zhou Honghui Teng Hoi Dick ng Pengfei Yang Zonglin Jiang School of Aerospace Engineering Beijing Institute of TechnologyBeijing100081China State Key Laboratory of Laser Propulsion and Application Beijing Power Machinery InstituteBeijing100074China Department of Mechanical Industrial and Aerospace EngineeringConcordia UniversityMontrealQCH3G 1M8Canada State Key Laboratory of High Temperature Gas Dynamics Institute of MechanicsChinese Academy of SciencesBeijing100190China School of Engineering Sciences University of Chinese Academy of SciencesBeijing100049China

The dynamics of frontal and transverse shocks in gaseous detonation waves is a complex phenomenon bringing many difficulties to both numerical and experimental *** laser-optical visualization of detonation structure may provide certain information of its reactive front,but the corresponding lead shock needs to be reconstructed building the complete flow *** the multi-layer perceptron(MLP)approach,we propose a shock front reconstruction method which can predict evolution of the lead shock wavefront from the state of the reactive *** method is verified through the numerical results of one-and two-dimensional unstable detonations based on the reactive Euler equations with a one-step irreversible chemical reaction *** show that the accuracy of the proposed method depends on the activation energy of the reactive mixture,which influences prominently the cellular detonation instability and hence,the distortion of the lead shock *** select the input variables for training and evaluate their influence on the effectiveness of the proposed method,five groups,one with six variables,and the other with four variables,are tested and analyzed in the MLP *** trained MLP is tested in the cases with different activation energies,demonstrates the inspiring generalization *** paper offers a universal framework for predicting detonation frontal evolution and provides a novel way to interpret numerical and experimental results of detonation waves.

关键词： Cellular detonation Lead shock evolution Multi-layer perceptron Numerical simulations

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Determination of the archaeal and bacterial communities in two-phase and single-stage anaerobic systems by 454 pyrosequencing

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Journal of Environmental Sciences 2015年第10期27卷 121-129页

作者： Yogananda Maspolim Yan zhou Chenghong Guo Keke Xiao Wun Jern ng Advanced Environmental Biotechnology Centre (AEBC) Nanyang Environment and Water Research Institute (NEWRI)Nanyang Technological University (NTU) School of Civil and Environmental Engineering Nanyang Technological University (NTU)

2-Phase anaerobic digestion（AD）, where the acidogenic phase was operated at 2 day hydraulic retention time（HRT） and the methanogenic phase at 10 days HRT, had been evaluated to determine if it could provide higher organic reduction and methane production than the conventional single-stage AD（also operated at 12 days HRT）. 454 pyrosequencing was performed to determine and compare the microbial communities. The acidogenic reactor of the 2-phase system yielded a unique bacterial community of the lowest richness and diversity, while bacterial profiles of the methanogenic reactor closely followed the single-stage reactor. All reactors were predominated by hydrogenotrophic methanogens, mainly Methanolinea. Unusually, the acidogenic reactor contributed up to 24%of total methane production in the 2-phase system. This could be explained by the presence of Methanosarcina and Methanobrevibacter, and their activities could also help regulate reactor alkalinity during high loading conditions through carbon dioxide production. The enrichment of hydrolytic and acidogenic Porphyromonadaceae, Prevotellaceae, Ruminococcaceae and unclassified Bacteroidetes in the acidogenic reactor would have contributed to the improved sludge volatile solids degradation, and ultimately the overall 2-phase system＇s performance. Syntrophic acetogenic microorganisms were absent in the acidogenic reactor but present in the downstream methanogenic reactor, indicating the retention of various metabolic pathways also found in a single-stage system. The determination of key microorganisms further expands our understanding of the complex biological functions in AD process.

关键词： Sewage sludge 2-Phase anaerobic digestion Microbial community 454 pyrosequencing Methanogen

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Experimental and numerical investigation of Weibullian behavior of grain crushing strength

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Geoscience Frontiers 2020年第2期11卷 401-411页

作者： Quanshui Huang Wei zhou Gang Ma Tang-Tat ng Kun Xu State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072China Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering Wuhan UniversityMinistry of EducationWuhan 430072China University of New Mexico AlbuquerqueNM87131USA

The Weibullian behavior of single grain crushing strength was investigated experimentally and numerically with the aim of enhancing the understanding of rock grain *** morphologies of pebble grains were obtained using white light 3D laser scanning and image processing.A grain shape library was constructed for grain shape analysis with different shape *** use of the shape library and grain stability analysis is discussed for a suggested procedure to rotate a grain to its most stable *** grain crushing tests were performed for 30 pebbles to obtain force-displacement curves and fracture *** grain was compressed diametrically between flat *** expected,the values of the stress at bulk fracture follow a Weibull distribution.A procedure for generating crushable agglomerates with realistic particle shapes was demonstrated,which was accomplished in the discrete element modeling(DEM)of the single grain crushing *** work presented here is novel in that both the heterogeneous micro-structures and randomly distributed flaws are *** DEM results demonstrate that the proposed modeling approach and calibrated parameters are reliable and can reflect the crushing behavior of rock ***,three parametric studies were presented evaluating the effects of micro-crack density,micro-crack disorder,and grain morphology on the Weibullian behavior of the crushing strength,none of which has previously been thoroughly *** three studies provide a deeper insight into the origin of the Weibullian behavior of single grain crushing strength.

关键词： Rock grain Grain crushing test Discrete element modeling 3D scanning technique Grain stability Weibullian behavior

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Inokosterone Is a Potential Drug Target of Estrogen Receptor 1 in Rheumatoid Arthritis Patients:Analysis from Active Ingredient of Cyathula Officinalis

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Chinese Journal of Integrative Medicine 2021年第10期27卷 767-773页

作者： MO Ji-hao XIE Han-kun zhou Ye-mian ng Sihan-benjamin LI Shao-xia WAng Lei Department of Medical Laboratory Luoyang Orthopedic Hospital of Henan ProvinceOrthopedic Institute of Henan ProvinceLuoyangHenan Province(471002)China Miller School of Medicine University of Miami(33136)MiamiFLUSA Institute of Technical Biology&Agriculture Engineering Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei(230031)China Eatobe Pte.Limited(573969) Singapore

Objective:To elucidate the active compounds and the molecular mechanism of Cyathula Off/c/na//s as a drug treatment for rheumatoid arthritis(RA).Methods:The target genes of active ingredients from Cyathula Officinalis were obtained from bioinformatics analysis tool for the molecular mechanism of traditional Chinese *** protein-protein interaction between the target genes were analyzed using STRIng and *** transcriptome of RA patients compared to healthy people(GSE121894)were analyzed using R program package *** relative expression of the target genes was obtained from the RNA-seq *** molecular docking analyses were processed based on the molecular model of estrogen receptor 1(ESR1)binding with estradiol(PDB ID:1A52).The binding details were analyzed by ***:Inokosterone,ecdysterone,and cyaterone were the 3 active ingredients from Cyathula Officinalis that bind to target *** all the significantly changed genes from RA patients,ESR1,ADORA1,and ANXA1 were significantly increased in mRNA samples of RA ***:ESR1,the transcription factor that binds inokosterone in the molecular binding analysis,is the target protein of Cyathula Officinalis.

关键词： rheumatoid arthritis estrogen receptor 1 inokosterone Cyathula Officinalis Chinese medicine

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Enhanced Microwave Absorption Properties of Double-Layer Absorbers Based on Spherical NiO and Co_(0.2)Ni_(0.4)Zn_(0.4)Fe_2O_4 Ferrite Composites

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Acta Metallurgica Sinica(English Letters) 2018年第2期31卷 171-179页

作者： Pei-Jiang Liu Zheng-Jun Yao Vincent Ming Hong ng Jin-Tang zhou Zhi-Hong Yang Ling-Bing Kong College of Materials and Technology Nanjing University of Aeronautics and Astronautics Nanjing 211100 China Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology Nanjing 211100 China School of Materials Science and Engineering Nanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore

Microwave absorption properties of spherical NiO particles and Co0.2Ni0.4Zn0.4Fe2O4（CNZF） ferrites with single-layer and double-layer absorbers were studied in the frequency range of 2–18 GHz. The spherical NiO particles were synthesized by using a hydrothermal process, while the CNZF powders were prepared by using a sol–gel autoignition method. The double-layer absorbers, composed of 30 wt% NiO as matching layer and 30 wt% CNZF as absorption layer,with a total thickness of 3.2 mm, exhibited a maximum reflection loss（RL） of –67.0 d B at 9.2 GHz and an effective absorbing bandwidth below –10 d B to be 3.9 GHz from 7.0 to 10.9 GHz. The excellent microwave absorption performance of the double-layer absorbers should be ascribed to the high impedance matching ratio, the great microwave attenuation capability, and well-coupled layer.

关键词： Hierarchical NiO particle Ferrite Impedance matching Microwave absorption property

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循环温度荷载下黏粒含量对黄土变形特性的影响（英文）

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2019年第12期20卷 979-990页

作者： Qing-yi MU Charles Wang-wai ng Chao zhou Gordon Gong-dan zhou Department of Civil Engineering Xi'an Jiaotong UniversityXi'an 710049China Department of Civil and Environmental Engineering The Hong Kong University of Science and TechnologyHong Kong 999077China Department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityHong Kong 999077China Key Laboratory of Mountain Hazards and Earth Surface Process Chinese Academy of Sciences(CAS)Chengdu 610041China

目的:1.探讨加热-降温循环温度荷载下黄土中黏土矿物对其变形特性的影响,包括累积塑性压缩变形和热膨胀系数。2.研究黄土由于施加温度荷载产生变形的微观机理。创新点:1.明确了对黄土由温度荷载引起累积塑性变形具有重要影响的矿物成分... 详细信息

目的:1.探讨加热-降温循环温度荷载下黄土中黏土矿物对其变形特性的影响,包括累积塑性压缩变形和热膨胀系数。2.研究黄土由于施加温度荷载产生变形的微观机理。创新点:1.明确了对黄土由温度荷载引起累积塑性变形具有重要影响的矿物成分;2.研究得到黄土由于施加温度荷载产生变形的微观机理。方法:1.通过溶液沉积法,分离黄土中的黏土矿物,并制备出三种不同黏土矿物含量的黄土测试样品;2.通过温控一维固结仪,测试不同黏土矿物含量的黄土在循环温度荷载下的累积塑性变形和热膨胀系数;3.通过扫描电镜试验和矿物成分测试,研究黄土由于施加温度荷载产生变形的微观机理。结论:1.黄土中所含伊利石、绿泥石、高岭石和蒙脱石等黏土矿物对其由于施加温度荷载所产生的累积塑性变形具有重要影响;2.黄土孔隙比对其由温度荷载引起的累积塑性变形和热膨胀系数影响较小。

关键词：黄土变形黏土矿物循环温度荷载

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Effect of a high strength chemical industry wastewater on microbial community dynamics and mesophilic methane generation

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Journal of Environmental Sciences 2014年第4期26卷 875-884页

作者： Harish Venkatakrishnan Youming Tan Maszenan bin Abdul Majid Santosh Pathak Antonius Yudi Sendjaja Dongzhe Li Jerry Jian Lin Liu Yan zhou Wun Jern ng School of Civil and Environmental Engineering Nanyang Technological University Advanced Environmental Biotechnology Center Nanyang Environment and Water Research Institute Nanyang Technological University School of Public Health Shanghai Jiaotong University Nanyang Environment and Water Research Institute Nanyang Technological University Sembcorp Industries Ltd.

A high strength chemical industry wastewater was assessed for its impact on anaerobic microbial com- munity dynamics and consequently mesophilic methane generation. Cumulative methane production was 251 mL/g total chemical oxygen demand removed at standard temperature and pressure at the end of 30 days experimental period with a highest recorded methane percentage of 80.6% of total biogas volume. Volatile fatty acids （VFAs） analysis revealed that acetic acid was the major intermediate VFAs produced with propionic acid accumulating over the experimental period. Quantitative analysis of microbial communities in the test and control groups with quantitative real time polymerase chain reaction highlighted that in the test group, Eubacteria （96.3%） was dominant in comparison with methanogens （3.7%）. The latter were dominated by Methanomicrobiales and Methanobacteriales while in test groups increased over the experimental period, reaching a maximum on day 30. Denaturing gradient gel electrophoresis profile was performed, targeting the 16S rRNA gene of Eubacteria and Archaea, with the DNA samples extracted at 3 different time points from the test groups. A phylogenetic tree was constructed for the sequences using the neighborhood joining method. The analysis revealed that the presence of organisms resembling Syntrophomonadaceae could have contributed to increased production of acetic and propionic acid intermediates while decrease of organisms resembling Pelotomaculum sp. could have most likely contributed to accumulation of propionic acid. This study suggested that the degradation of organic components within the high strength industrial wastewater is closely linked with the activity of certain niche microbial communities within eubacteria and methanogens.

关键词： biochemical methane potential biogas community dynamics denaturing gradient gel electrophoresis industrial chemical wastewater quantitative real-time PCR

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