检索结果-南通市图书馆

Undrained vane shear strength of sand-foam mixtures subjected to different shear rates

Journal of Rock Mechanics and Geotechnical Engineering 2023年第6期15卷 1591-1602页

作者： Jiazheng Zhong shuying wang Tongming Qu School of Civil Engineering Central South UniversityChangsha410075China Tunnel and Underground Engineering Research Center Central South UniversityChangsha410075China Department of Civil and Environmental Engineering The Hong Kong University of Science and TechnologyClearwater BayHong KongChina

The shear strength of sand-foam mixtures plays a crucial role in ensuring successful earth pressure balance(EPB)shield *** the sand-foam mixtures are constantly sheared by the cutterhead and the screw conveyor with varied rotation speeds during tunneling,it is non-trivial to investigate the effect of shear rates on the undrained shear strength of sand-foam mixtures under chamber pressures to extend the understanding on the tunneling *** study conducted a series of pressurized vane shear tests to investigate the role of shear rates on the peak and residual strengths of sand-foam mixtures at different pore *** from the shear-rate characteristics of natural sands or clay,the results showed that the peak strength of sand-foam mixtures under high vertical total stress(σ_(v)≥200 kPa)and low foam injection ratio(FIR30%)decreased with the increase in shear ***,the peak strength was not measurably affected by shear *** sand-foam mixtures in the residual state resembled low-viscous fluid with yield stress and the residual strength increased slightly with shear *** addition,the peak and residual strengths were approximately linear with vertical effective stress regardless of the total stress and *** peak effective internal friction angle remained almost invariant in a low shear rate(γ′<0.25 s1)but decreased when the shear rate continued *** residual effective internal friction angle was lower than the peak counterpart and insensitive to shear *** study unveiled the role of shear rates in the undrained shear strength of sand-foam mixtures with various FIRs and vertical total *** findings can extend the understanding of the rate-dependent shear characteristics of conditioned soils and guide the decision-making of soil conditioning schemes in the EPB shield tunneling practice.

关键词： Sand-foam mixture Shear rate Peak and residual strengths Effective stress Effective internal friction angle

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Optimization of phosphorus removal in uniFed SBR system for domestic wastewater treatment

引用

Frontiers of Environmental Science & Engineering 2010年第4期4卷 475-481页

作者： Xuguang TANG shuying wang Yongzhen PENG Key Laboratory of Beijing Water Quality Science and Water Environment Recovery Engineering Beijing University of TechnologyBeijing 100124China

The characteristic of phosphorus removal andappropriate change of the traditional operation modes wereinvestigated in UniFed sequencing batch reactor (SBR)laboratory-scale apparatus (40 L), treating actual domesticwastewater with low ratios of C/N (2.57) and C/P (30.18),providing theoretical basis for actual application ofwastewater treatment plant. UniFed SBR system with itsunique operation mode had the distinct superiority ofphosphorus removal. On this occasion, the effect ofvolumetric exchange ratio (VER) and the method ofinfluent introduction for phosphorus removal were *** the carbon source became the limiting factor tophosphorus release, the higher the VER, the lower thephosphorus concentration in the effluent. Three differentinfluent patterns, including one-time filling, four-timefilling, and continuous filling with the same quantity ofwastewater could increase the release rate of anaerobicphosphorus from 0.082 to 0.143 mg·P·(L·min)-1. Appropriatechange of the traditional operation modes couldoptimize the efficiency of phosphorus removal. When thefeed/ decant time was extended from 2 h to 4 h, thephosphorous removal efficiency increased from 59.93% to88.45% without any external carbon source. In the mode ofalternation of anoxic-aerobic (A/O) condition, phosphorousremoval efficiency increased from 55.07% to 72.27%clearly. The carbon source in the influent can be usedadequately, and denitrifying phosphorus removal wascarried out in anoxic stage 2 (A2). This mode was optimalfor the treatment of actual domestic wastewater with lowC/N and C/P ratios.

关键词： UniFed sequencing batch reactor(SBR) phosphorus removal volumetric exchange ratio(VER) alternation of anoxic-aerobic(A/O) domestic wastewater

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Production of N2O in two biologic nitrogen removal processes： a comparison between conventional and short-cut Nitrogen removal processes

引用

Frontiers of Environmental Science & Engineering 2014年第4期8卷 589-597页

作者： Youkui GONG Yongzhen PENG shuying wang Sai wang Shijiazhuang Institute of Railway Technology Shijiazhuang 050061 China School of Environmental and Energy Engineering Beijing University of Technology Beijing 100022 China

The N2O production in two nitrogen removal processes treating domestic wastewater was investigated in laboratory-scale aerobic-anoxic sequencing batch reactors （SBRs）. Results showed that N2O emission happened in the aerobic phase rather than in the anoxic phase. During the aerobic phase, the nitrogen conversion to N2O gas was 27.7% and 36.8% of NH＋-N loss for conventional biologic N-removal process and short-cut biologic N-removal process. The dissolved N2O was reduced to N2 in the anoxic denitrification phase. The N2O production rate increased with the increasing of nitrite concentration and ceased when NH＋-N oxidation was terminated. Higher nitrite accumulation resulted in higher NEO emission in the short-cut nitrogen removal process. Pulse-wise addition of 20 mg NO2 -N. L- 1 gave rise to 3-fold of N2O emission in the conventional N-removal process, while little change happened with 20 mg NOS-N L-1 was added to SBR1.

关键词： conventional N-removal process N2O short- cut N-removal process nitrite accumulation ammonia-oxidizing bacteria (AOB) denitrification

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Achieving nitritation at low temperatures using free ammonia inhibition on Nitrobacter and real-time control in an SBR treating landfill leachate

引用

Journal of Environmental Sciences 2015年第4期27卷 157-163页

作者： Hongwei Sun Yongzhen Peng shuying wang Juan Ma Key Laboratory of Beijing Water Quality Science and Water Environment Recovery Engineering Beijing University of Technology School of Environmental and Municipal Engineering Lanzhou Jiaotong University

Free ammonia（FA） inhibition on nitrite-oxidized bacteria（NOB） and real-time control are used to achieve nitrogen removal from landfill leachate via nitrite pathway at low temperatures in sequencing batch reactor. The inhibition of FA on NOB activity during the aerobic period was prolonged using real-time control. The degree of nitrite accumulation was monitored along with variations of the ammonia-oxidizing bacteria and NOB population using fluorescence in situ hybridization techniques. It is demonstrated that the end-point of ammonia oxidization is detected from the on-line measured dissolved oxygen,oxidization–reduction potential, and p H signals, which could avoid the loss the FA inhibition on NOB caused by excess aeration. At low temperature（13.0–17.6°C）, the level of nitrite pathway rapidly increased from 19.8% to 90%, suggesting that nitritation was successfully started up at low temperature by applying syntrophic association of the FA inhibition and real-time control, and then this high level of nitrite pathway was stably maintained for as long as 233 days. Mechanism analysis shows that the establishment of nitritation was primarily the result of predominant ammonia-oxidizing bacteria developed in the nitrifying bacteria population compared to NOB. This was mainly due to a gradual reduction of nitrite amount that is available to provide energy for the growth of NOB,eventually leading to the elimination of NOB from the bacterial clusters in sequencing batch reactor sludge system.

关键词： Landfill leachate Nitritation Low temperature Free ammonia Inhibition AOB and NOB

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Material point method simulation of hydro-mechanical behaviour in twophase porous geomaterials: A state-of-the-art review

引用

Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2341-2350页

作者： Xiangcou Zheng shuying wang Feng Yang Junsheng Yang School of Civil Engineering Central South UniversityChangsha410075China Geo-Engineering Section Faculty of Civil Engineering and GeosciencesDelft University of TechnologyDelftthe Netherlands

The material point method(MPM)has been gaining increasing popularity as an appropriate approach to the solution of coupled hydro-mechanical problems involving large *** this paper,we survey the current state-of-the-art in the MPM simulation of hydro-mechanical behaviour in two-phase porous *** review covers the recent advances and developments in the MPM and their extensions to capture the coupled hydro-mechanical problems involving large *** focus of this review is aiming at providing a clear picture of what has or has not been developed or implemented for simulating two-phase coupled large deformation problems,which will provide some direct reference for both practitioners and researchers.

关键词： Coupled problems Hydro-mechanical behaviour Large deformation Material Point Method(MPM)

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Denitrifying phosphorus removal in a step-feed CAST with alternating anoxic-oxic operational strategy

引用

Journal of Environmental Sciences 2009年第9期21卷 1169-1174页

作者： MA Juan PENG Yongzhen wang shuying wang Li LIU Yangt MA Ningpin Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering College of Environmental and Energy Engineering Beijing University of Technology Beijing 100124 China. China Water Holdings Private Limited 28 Kaki Bukit Crescent Kaki Bukit Techpark I S416259 416259 Singpore.

A bench-scale cyclic activated sludge technology （CAST） was operated to study the biological phosphorus removal performance and a series of batch tests was carried out to demonstrate the accumulation of denitrifying polyphosphate-accumulating organisms （DNPAOs） in CAST system. Under all operating conditions, step-feed CAST with enough carbon sources in influent had the highest nitrogen and phosphorus removal efficiency as well as good sludge settling performance. The average removal rate of COD, NH4^＋-N, PO4^3--P and total nitrogen （TN） was 88.2%, 98.7%, 97.5% and 92.1%, respectively. The average sludge volume index （SVI） was 133 mL/g. The optimum anaerobic/aerobic/anoxic （AOA） conditions for the cultivation of DNPAOs could be achieved by alternating anoxic/oxic operational strategy, thus a significant denitrifying phosphorus removal occurred in step-feed CAST. The denitrification of NO^x--N completed quickly due to step-feed operation and enough carbon sources, which could enhance phosphorus release and further phosphorus uptake capability of the system. Batch tests also proved that polyphosphate-accumulating organisms （PAOs） in the step-feed process had strong denitrifying phosphorus removal capacity. Both nitrate and nitrite could be used as electron acceptors in denitrifying phosphorus removal. Low COD supply with step-feed operation strategy would favor DNPAOs accumulation.

关键词： cyclic activated sludge technology biological phosphorus removal denitrifying polyphosphate-accumulating organisms

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Impact of Anthracene Addition on Microbial Community Structure in Soil Microcosms from Contaminated and Uncontaminated Sites

引用

Biomedical and Environmental Sciences 2011年第5期24卷 543-549页

作者： wang QingFeng ZHANG shuying ZOU Li XIE ShuGuang College of Environmental Sciences and Engineering Peking University Beijing 100871 China

Objective This paper aims to investigate the impact of anthracene addition on microbial community in agricultural soil irrigated with tap water or reclaimed *** The changes of microbial community were characterized by terminal restriction fragment length polymorphism in combination with 16S rRNA gene clone library *** A significant change in microbial community composition was observed during the biodegradation of anthracene,with dominantly enriched members from the genus *** This work might be useful for developing techniques for the isolation of novel putative PAH degrader.

关键词： Biodegradation Microbial community Methylophilus Reclaimed wastewater Polycyclic aromatic hydrocarbons (PAHs)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The effect of salinity on waste activated sludge alkaline fermentation and kinetic analysis

引用

Journal of Environmental Sciences 2016年第5期28卷 80-90页

作者： Baodan Jin shuying wang Liqun Xing Baikun Li Yongzhen Peng Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering Engineering Research Center of BeijingBeijing University of Technology Department of Civil and Environmental Engineering University of Connecticut

The effect of salinity on sludge alkaline fermentation at low temperature（20°C） was investigated, and a kinetic analysis was performed. Different doses of sodium chloride（Na Cl, 0–25 g/L） were added into the fermentation system. The batch-mode results showed that the soluble chemical oxygen demand（SCOD） increased with salinity. The hydrolysate（soluble protein, polysaccharide） and the acidification products（short chain fatty acids（SCFAs）, NH＋4–N, and PO_4^（3-）–P） increased with salinity initially, but slightly declined respectively at higher level salinity（20 g/L or 20–25 g/L）. However, the hydrolytic acidification performance increased in the presence of salt compared to that without ***, the results of Haldane inhibition kinetics analysis showed that the salt enhanced the hydrolysis rate of particulate organic matter from sludge particulate and the specific utilization of hydrolysate, and decreased the specific utilization of SCFAs. Pearson correlation coefficient analysis indicated that the importance of polysaccharide on the accumulation of SCFAs was reduced with salt addition, but the importance of protein and NH＋4–N on SCFA accumulation was increased.

关键词： Alkaline anaerobic fermentation Sodium chloride Hydrolytic acidification Short chain fatty acids Haldane inhibition kinetics Pearson correlation coefficient

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Practical consideration for design and optimization of the step feed process

引用

Frontiers of Environmental Science & Engineering 2013年第1期7卷 135-142页

作者： Shijian GE Yongzhen PENG Congcong LU shuying wang College of Environmental and Energy Engineering Key Laboratory of Beijing Water Quality Science and Water Environment Recovery Engineering Beijing University of Technology Beijing 100124 China

Based on the anoxic/oxic (A/O) step feed process, a modified University of Cape Town (UCT) step feed process was developed by adding an anaerobic zone and adjusting sludge return pipeline. Performance evaluation of these two types of processes was investigated by optimizing operational parameters, such as the anaerobic/anoxic/oxic volumes, internal recycle ratios, and sludge retention times, for removal of chemical oxygen demanding (COD), nitrogen, and phosphorus. Results showed high removal efficiencies of COD of (85.0±1.7)%, ammonium of (99.7±0.2)%, total nitrogen (TN) of (85.5±1.7)%, phosphorus of (95.1±3.3)%, as well as excellent sludge settleability with average sludge volume index of (83.7±9.5) L·mg−1 in the modified UCT process. Moreover, (61.5±6.0)% of influent COD was efficiently involved in denitrification or phosphorus release process. As much as 35.3% of TN was eliminated through simultaneous nitrification and denitrification process in aerobic zones. In addition, the presence of denitrifying phosphorus accumulating organisms (DNPAOs), accounting for approximately 39.2% of PAOs, was also greatly beneficial to the nitrogen and phosphorus removal. Consequently, the modified UCT step feed process was more attractive for the wastewater treatment plant, because it had extremely competitive advantages such as higher nutrient removal efficiencies, lower energy and dosages consumption, excellent settling sludge and operational assurance.

关键词： step feed anoxic/oxic (A/O) University of Cape Town (UCT) simultaneous nitrification and denitrification (SND) denitrifying phosphorus removal biological nutrient removal (BNR)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Nitrogen and phosphorus removal in pilot-scale anaerobic-anoxic oxidation ditch system

引用

Journal of Environmental Sciences 2008年第4期20卷 398-403页

作者： PENG Yongzhen HOU Hongxun wang shuying CUI Youwei Zhiguo Yuan Key Laboratory of Beijing for Water Environment Recovery Engineering Beijing University of Technology Beijing 100022 China Advanced Wastewater Management Centre （AWMC） the University of Queensland St. Lucia Brisbane 4072 Australia

To achieve high efficiency of nitrogen and phosphorus removal and to investigate the rule of simultaneous nitrification and denitrification phosphorus removal （SNDPR）, a whole course of SNDPR damage and recovery was studied in a pilot-scale, anaerobicanoxic oxidation ditch （OD）, where the volumes of anaerobic zone, anoxic zone, and ditches zone of the OD system were 7, 21, and 280 L, respectively. The reactor was fed with municipal wastewater with a flow rate of 336 L/d. The concept of simultaneous nitrification and denitrification （SND） rate （rSND） was put forward to quantify SND. The results indicate that：（1） high nitrogen and phosphorus removal efficiencies were achieved during the stable SND phase, total nitrogen （TN） and total phosphate （TP） removal rates were 80% and 85%, respectively; （2） when the system was aerated excessively, the stability of SND was damaged, and rSND dropped from 80% to 20% or less; （3） the natural logarithm of the ratio of NOx to NH4^＋ in the effluent had a linear correlation to oxidation-reduction potential （ORP）; （4） when NO3^- was less than 6 mg/L, high phosphorus removal efficiency could be achieved; （5） denitrifying phosphorus removal （DNPR） could take place in the anaerobic-anoxic OD system. The major innovation was that the SND rate was devised and quantified.

关键词： oxidation ditch biological nitrogen removal biological phosphorus removal simultaneous nitrification and denitrification (SND) pilot scale municipal wastewater

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：