检索结果-内蒙古大学图书馆

作者： Wu, J. Zhang, J.B. Jiang, Y. Cao, Z.P. Poncin, S. Li, H.Z. State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing 100084 China Laboratory of Reactions and Process Engineering Nancy-Université CNRS 1 rue Grandville 54001 Nancy Cedex France

An investigation of hydrodynamic conditions and their impacts on sludge digestion in internal circulation anaerobic digester (ICAD) was conducted. This novel sludge digester employing upflow reactor concept was composed of reaction zone, riser and downcomer, etc. Part of the generated biogas was injected to the reaction zone to intensify the circulation in ICAD in order to enhance the mass transfer. The advanced particle image velocimetry was used to explore the hydrodynamic conditions at micro scale. The results revealed that the average shear rate in the reaction zone and downcomer was linearly correlated with the Reynolds number;the shear rates in ICAD revealed an order as riser > downcomer > reaction zone. Thermophilic digestion of waste activated sludge in a pilot ICAD for 5.25 d combined with thermal pretreatment at 60 °C for 1 d was conducted under various hydrodynamic conditions. The survey at global level demonstrated that both the longer sludge retention time than the hydraulic retention time and the satisfactory mass transfer could be realized and as consequences, the maximal biogas production rate and VSS removal were obtained when the Reynolds number of the reaction zone was approximately 0.53. This digester under the optimal hydrodynamic conditions demonstrated good degradation capacity and buffer capability to resist various shock loadings. © 2012 Elsevier Ltd. All rights reserved.

关键词： Reynolds number

来源：评论

学校读者我要写书评

暂无评论

Effects of operating parameters on oxidative coupling of methane over Na-W-Mn/SiO_2 catalyst at elevated pressures

引用

Journal of Natural Gas Chemistry 2011年第2期20卷 204-213页

作者： Jafar Sadeghzadeh Ahari Mohammad Taghi Sadeghi Saeed Zarrinpashne Process Simulation and Control Laboratory Chemical Engineering College Iran University of Science and Technology (IUST) Gas Research Division-Research Institute of Petroleum Industry (RIPI)

The effects of operating parameters on oxidative coupling of methane （OCM） over Na-W-Mn/SiO2 catalyst have been studied at elevated pressures of 0.2, 0.3 and 0.4 MPa under low gaseous hourly space velocity （GHSV） and low temperature conditions. Experimental results show that when the operating pressure is increased, C2＋ yield slightly decreases, while the maximum ratio of ethylene to ethane remains unchanged. Moreover, it has been found empirically that increase of pressure does not affect the catalyst behavior permanently, the catalyst recovers its original low pressure performance without hysteresis behavior by reducing the pressure. Under the investigated conditions, when oxygen is completely consumed, the increase of GHSV leads to improvement in C2 selectivity, while C3＋ and COx selectivities decrease slightly. The C2＋ selectivity increases by increase of nitrogen diluent in the feed, but the C3＋ hydrocarbons selectivities decrease with increase of nitrogen since it is possible that further dilution at high pressure may reduce the probability of collision between CH3 and C2＋ hydrocarbons. During the stability test at high pressure, the catalyst performance remains unchanged throughout the 20 h running. The fresh and used catalysts were characterized using XRD, SEM and N2 adsorption-desorption methods. It was found that the phase transformation of the support from α-cristobalite to tridymite and quartz does not have obvious effect on catalyst performance at high pressure.

关键词： operating parameters oxidative coupling of methane Na-W-Mn/SiO2 catalyst elevated pressure

来源：评论

学校读者我要写书评

暂无评论

Spectral response of rice(Oryza sativa L.) leaves to Fe^(2+) stress

引用

Science China(Life Sciences) 2009年第8期52卷 747-753页

作者： CHI GuangYu1,2,CHEN Xin1,SHI Yi1 & LIU XinHui3 1 Key laboratory of Terrestrial Ecological process,Institute of Applied Ecology,Chinese Academy of Sciences,Shenyang 110016,China 2 Graduate School of Chinese Academy of Sciences,Beijing 100049,China 3 State Key Joint laboratory of Environmental simulation and Pollution control,School of Environment,Beijing Normal University,Beijing 100875,China Key Laboratory of Terrestrial Ecological Process Institute of Applied Ecology Chinese Academy of Sciences Shenyang China Graduate School of Chinese Academy of Sciences Beijing China State Key Joint Laboratory of Environmental Simulation and Pollution Control School of Environment Beijing Normal University Beijing China

In the management of lake eutrophication,the regulation effect of Fe is considered,in addition to the controlling nitrogen-and phosphorus *** on the "Fe hypothesis",this paper tentatively applied plant spectral response to the remote sensing early-warning mechanism of lake eutrophication.A laboratory water culture experiment with rice(Oryza sativa L.) was conducted to study Fe uptake by plants and the chlorophyll concentration and visible-near infrared spectrum of vegetable leaves as well as their interrelations under Fe2+ *** spectral indices,i.e.,A1(integral value of the changes of spectral reflectivity in the range 460―670 nm under Fe2+ stress),A2(integral value of the changes of spectral reflectivity in the range of 760―1000 nm under Fe2+ stress) and S(blue-shift range of red edge curve under Fe2+ stress),were used to establish quantitative models about the relationships between the rice leaf spectrum and Fe2+ *** the increase of Fe2+ in a culture solution,the Fe content in rice plants increased,while the chlorophyll concentration in vegetative leaves *** spectral reflectivity of vegetable leaves increased in the visible light band but decreased in the near infrared band,and the blue-shift range of the red edge curve *** indices A1,A2 and S all had significant correlations with the Fe content in rice leaves,the correlation coefficient being respectively 0.951(P < 0.01),?0.988(P < 0.01) and 0.851(P < 0.01),and simulated(multiple correlation coefficients R2 > 0.96) and predict the Fe level in rice leaves.

关键词： rice(Oryza sativa L.) spectrum Fe2+ lake eutrophication

来源：评论

学校读者我要写书评

暂无评论

Fault Detection and Diagnosis in the DAMADICS Benchmark Actuator System – A Hidden Markov Model Approach

引用

IFAC Proceedings Volumes 2008年第2期41卷 12419-12424页

作者： Gustavo M. de Almeida Song W. Park Department of Chemical Engineering School of Engineering Federal University of Minas Gerais Brazil Laboratory of Simulation and Process Control (LSCP) Department of Chemical Engineering Polytechnic School University of Sao Paulo Brazil

Early fault detection and diagnosis in chemical process monitoring represents a challenge to be overcome. Another one concerns the spatial overlapping problem among distinct fault classes, once some events may only be distinguished from the others by taking into account its order of occurrence. The hidden Markov model (HMM) technique is capable of providing information about the tendency of the process and of modelling ordered data. Hence, the goal is to investigate the contribution of this technique to both aspects related to process monitoring activities. The case study is based on the DAMADICS benchmark actuator system. Both abrupt and incipient faulty events were investigated. To the former, detection and diagnosis tasks were immediately satisfied; and to the latter, they were carried out in a progressive and correct course.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Implementation and design of a communication system of an agent-based automated substation

引用

Frontiers of Electrical and Electronic Engineering in China 2006年第4期1卷 396-399页

作者： LIN Yong-jun LIU Yu-tao ZHANG Dan-hui Industry Process Simulation and Control Laboratory North China Electric Power UniversityBaoding 071003China Department of Mathematic Application North China Electric Power UniversityBaoding 071003China

A substation system requires that communica-tion be transmitted reliably,accurately and in *** at solving problems,e.g.,flow confliction and sensi-tive data transmission,a model of the communication sys-tem of an agent-based automated substation is *** running principle is discussed in detail and each type of agent is discussed *** the end,the realization of the agent system applied to the substation is *** outcome shows that the communication system of an agent-based automated substation improves the accuracy and reliability of the data transfer and presents it in real-time.

关键词： data transfer substation automation agent system communication system

来源：评论

学校读者我要写书评

暂无评论

MULTI MODEL APPROACH TO MULTIVARIABLE LOW ORDER STRUCTURED-controlLER DESIGN

引用

IFAC Proceedings Volumes 2006年第2期39卷 1021-1026页

作者： M. Escobar J.O. Trierweiler Laboratory of Process Control and Integration (LACIP) Group of Integration Modelling Simulation Control and Optimization of Processes (GIMSCOP) Department of Chemical Engineering Federal University of Rio Grande do Sul

The method presented here offers an effective and time saving tool for robust low order multivariable controller design. The relation between controller complexity and closed loop performance can easily be evaluated. The method consists of five steps: 1. A desired behavior of the closed loop system is specified. Considering the nonminimum phase part of the process model the closed loop attainable performance is determined. 2. The process model and the attainable performance are scaled by the RPN-scaling procedure. 3. This defines an “ideal” scaled controller, which is usually too complex to be realized. 4. The frequency response of the ideal scaled compensator is approximated by a simpler one with structure and order chosen by the user. 5. Since the approximation in frequency response is performed with the scaled system, it is necessary to return to the original system's units. This procedure can be implemented using a multi-model approach, what increase the robustness of synthesized controller.

关键词： multivariable project design frequency domain multi models low order controllers

来源：评论

学校读者我要写书评

暂无评论

FUZZY IDENTIFICATION OF BIOprocessES APPLYING TSK-TYPE MODELS WITH CONSEQUENT PARAMETER ESTIMATION THROUGH ORTHOGONAL ESTIMATOR

引用

IFAC Proceedings Volumes 2002年第1期35卷 283-288页

作者： Rosimeire Aparecida Jerônimo Claudio Garcia Oscar A.Z. Sotomayor Department of Telecommunications and Control Engineering Laboratory of Automation and Control (LAC) Department of Chemical Engineering Laboratory of Simulation and Process Control (LSCP) Polytechnic School of the University of São Paulo Av. Prof. Luciano Gualberto Trav. 3 n. 158 Cidade Universitária CEP 05508-900 São Paulo - SP Brazil

This paper presents fuzzy identification of two bioprocesses employing TSK-type models. A “Modified Gram-Schmidt” (MGS) orthogonal estimator is used to estimate the consequent parameters. This approach is then applied to identify two distinct cases involving dissolved oxygen concentration: one related to a bioreactor and the other one related to an activated sludge process. The obtained models are then cross-validated.

关键词： System identification Bioprocesses Nonlinear models Fuzzy modeling TSK-type models Modified Gram-Schmidt algorithm Parameter estimation

来源：评论

学校读者我要写书评

暂无评论

Modeling and simulation of hybrid dynamical systems with generalized differential Petri nets

Modeling and simulation of hybrid dynamical systems with gen...

引用

IEEE International Symposium on Intelligent control (ISIC)

作者： Yali Wu Weimin Wu Jianchao Zeng Guoji Sun Hongye Su Jian Chu System Engineering Institute Xi''an Jiaotong University Xi'an China Institute of Advanced Process Control National Laboratory of Industrial Control Technology Zhejiang University Hangzhou China Division of System Simulation and Computer Application Taipan Heavy Machinery Institute Taipan China

There has been considerable interest in the modeling and simulation of hybrid dynamic systems (HDS). As an effective modeling tool of discrete event dynamic systems, Petri nets have a dual nature of a graphical tool and a mathematical object. In this paper, an extension of Petri net named generalized differential Petri nets (GDPN) is proposed to model HDS that have a combination of discrete-event evolution and continuous state evolution. Differential place and differential transition defined by Demongodin et al. (1998) are used to model the numeral simulation of the continuous dynamic process, and the weights defined on the directed arcs that connects the differential transitions and places are extended from real numbers to real matrices. The marking of differential place are also enlarged from real numbers to real vectors. Then the evolution rules and modeling method of HDS with GDPN are introduced. Two examples are used to illustrate the modeling power of GDPN in HDS.

关键词： Petri nets Power system modeling Supervisory control Discrete event systems process control Computational modeling Computer simulation Mathematical model Chemical processes Continuous time systems

来源：评论

学校读者我要写书评

暂无评论

An Anti-Windup Decoupling Nonlinear control for a Paper Machine Headbox

引用

IFAC Proceedings Volumes 2000年第10期33卷 893-898页

作者： Paulo Nobile Diniz Song Won Park Jocelyn Freitas Bennaton Laboratory of Simulation and Process Control (LSCP) – Department of Chemical Engineering Polytechnic School of the University of São Paulo Laboratory of Automation and Control (LAC) – Department of Electronic Engineering Polytechnic School of the University of São Paulo Fax: +55-11-813.2380

Since most of the chemical processes are represented typically by nonlinear models, the use of nonlinear geometric control in chemical processes is straightforward. This paper presents a decoupling application in a paper machine headbox. The nonlinear geometric control is implemented with blocks for reference trajectory, tracking error, integrators of error feedback and with an anti-windup scheme. The results show a clear implementation scheme and good dynamical responses.

关键词： Affine Closed-loop controllers Decoupling problems Feedforward compensation Geometric approaches Nonlinear models Nonlinear control Paper industry

来源：评论

学校读者我要写书评

暂无评论

Kinetic model for kraft pulping of hardwood

引用

INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH 1996年第3期35卷 856-863页

作者： Giudici, R Park, SW LSCP−Process Control and Simulation Laboratory Department of Chemical Engineering University of São Paulo Polytechnic School P.O. Box 61548 05424-970 São Paulo Brazil

A comprehensive model for the kraft pulping kinetics of Eucalyptus saligna hardwood is presented. Kinetic parameters were estimated by fitting the model to available experimental data taken from the literature over a range of process variables. The model takes into account the effect of hydroxide and sulfide concentration in the liquor as well as the temperature-time history of the cooking. Model predictions were successfully compared with an independent set of bench-scale plant data for lignin and carbohydrate dissolution. The model is able to predict quite well the trends of the process variables.

关键词： Wood Carbohydrates Kinetic modeling Biopolymers Organic polymers

来源：评论

学校读者我要写书评

暂无评论

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

请选择保存的检索档案：

请选择收藏分类：

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

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

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：