检索结果-南通市图书馆

Real-time estimation of the structural utilization level of segmental tunnel lining

Underground Space 2024年第4期17卷 132-145页

作者： Nicola Gottardi Steffen Freitag gunther meschke Institute for Structural Mechanics Ruhr University BochumBochum 44801Germany Institute for Structural Analysis Karlsruhe Institute of TechnologyKarlsruhe 76131Germany

Over the last decades,an expansion of the underground network has been taking place to cope with the increasing amount of moving people and *** a consequence,it is of vital importance to guarantee the full functionality of the tunnel network by means of preventive maintenance and the monitoring of the tunnel lining state over time.A new method has been developed for the real-time prediction of the utilization level in tunnel segmental linings based on input monitoring *** new concept is founded on a framework,which encompasses an offline and an online *** the former,the generation of feedforward neural networks is accomplished by employing synthetically produced *** element simulations of the lining structure are conducted to analyze the structural response under multiple loading *** scenarios are generated by assuming ranges of variation of the model input parameters to account for the uncertainty due to the not fully determined in situ *** and target quantities are identified to better assess the structural utilization of the *** latter phase consists in the application of the methodological framework on input monitored data,which allows for a real-time prediction of the physical quantities deployed for the estimation of the lining *** approach is validated on a full-scale test of segmental lining,where the predicted quantities are compared with the actual ***,it is investigated the influence of artificial noise added to the training data on the overall prediction performances and the benefits along with the limits of the concept are set out.

关键词： Segmental lining Artificial neural networks Structural utilization level Real-time prediction Structural health monitoring Monitoring data

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

A simulation-based software to support the real-time operational parameters selection of tunnel boring machines

引用

Underground Space 2024年第1期14卷 176-196页

作者： Yaman Zendaki Ba Trung Cao Abdullah Alsahly Steffen Freitag gunther meschke Institute for Structural Mechanics Ruhr University BochumBochum 44801Germany Institute for Structural Analysis Karlsruhe Institute of TechnologyKarlsruhe 76131Germany

With the fact that the main operational parameters of the construction process in mechanized tunneling are currently selected based on monitoring data and engineering experience without exploiting the advantages of computer methods,the focus of this work is to develop a simulation-based real-time assistant system to support the selection of operational *** choice of an appropriate set of these parameters(i.e.,the face support pressure,the grouting pressure,and the advance speed)during the operation of tunnel boring machines(TBM)is determined by evaluating different tunneling-induced soil-structure interactions such as the surface settlement,the associated risks on existing structures and the tunnel lining *** evaluate soil-structure behavior,an advanced process-oriented numerical simulation model based on the finite cell method is *** enable the real-time prediction capability of the simulation model for a practical application during the advancement of TBMs,surrogate models based on the Proper Orthogonal Decomposition and Radial Basis Functions(POD-RBF)are *** proposed approach is demonstrated through several synthetic numerical examples inspired by the data of real tunnel *** developed methods are integrated into a user-friendly application called SMART to serve as a support platform for tunnel engineers at construction *** to each user adjustment of the input parameters,i.e.,each TBM driving scenario,approximately two million outputs of soil-structure interactions are quickly predicted and visualized in seconds,which can provide the site engineers with a rough estimation of the impacts of the chosen scenario on structural responses of the tunnel and above ground structures.

关键词： Numerical simulation Surrogate model Real-time prediction Proper orthogonal decomposition Radial basis functions TBM operation Smart construction

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

A holistic approach for the investigation of lining response to mechanized tunneling induced construction loadings

引用

Underground Space 2018年第1期3卷 45-60页

作者： Vojtech Ernst Gall Ahmed Marwan Mario Smarslik Markus Obel Peter Mark gunther meschke Inustitute for Structural Mechanics Ruhr University BochumBochunGermany Institute of Concrete Structures Ruhr University BochumBochumGermany

Design methods for segmental tunnel linings used in mechanized tunnel constructions typically employ numerical bedded beam mod-els and/or classical analytical solutions for the determination of structural forces(*** and shear and axial forces)and simple load spreading assumptions for the design of the reinforcement in joint *** effcient such methods may be,many physical details are often overlooked and/or oversimpliﬁed in the process of reducing the actual structure to a structural beam model,***-lytically derived loadings are employed,the grouting and ground reactions are reduced to a spring bedding,and the conﬁnement due to grouting at the longitudinal joint is largely not considered in reinforcement *** a design process is not able to account for,or predict,the susceptibility of tunnel linings to often observed damages that,although they may not be structurally relevant,lead to ser-viceability or durability issues,such as crack development or chipping at the segment *** methods,such as the Finite Element Method,provide an opportunity to model the segmental tunnel lining and its response to the entire TBM construction process and to explicitly model the crack development within individual segments using modern methods to model the discontinuities in *** this contribution,a holistic modeling procedure for the representation of the tunnel lining within the tunneling process is pro-posed and compared to traditional lining models.A 3D process oriented Finite Element model is used to calculate the predicted forces on the tunnel lining and the obtained results are compared with those generated by traditional ***,the predicted defor-mations are then transferred to a detailed segment model in which the nonlinear response of the segment at the longitudinal joint is mod-eled using an interface element based approach to simulate concrete cracking.

关键词： Mechanized tunneling Segmental tunnel linings Finite element method

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

Editorial

引用

Underground Space 2018年第4期3卷 251-251页

作者： Gunter Hofstetter gunther meschke Kok-Kwang Phoon University of Innsbruck Austria Ruhr University Bochum Germany National University of Singapore Singapore

This special issue of Underground Space contains extended papers related to selected contributions at the International Conference on Computational Methods in Tunneling and Subsurface Engineering(EURO:TUN 2017).EURO:TUN 2017 was organized at the University of Innsbruck,*** was the fourth conference of a series of successful ECCOMAS Thematic Conferences on Computational Methods in Tunneling,which started in 2007 in Vienna and continued in 2009 and 2013 in Bochum.

关键词： continued Editorial organized

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

A Glimpse into the Natural History of Leiolepis rubritaeniata Mertens,1961(Squamata:Leiolepididae)

引用

Asian Herpetological Research 2023年第2期14卷 147-155页

作者： gunther KÖHLER Panupong THAMMACHOTI Senckenberg Forschungsinstitut und Naturmuseum Senckenberganlage 25Frankfurt a.M.60325Germany Department of Biology Faculty of ScienceChulalongkorn UniversityBangkok 10330Thailand

During the months of April through July 2020 we studied aspects of the natural history of Leiolepis rubritaeniata,a species of butterfly lizard that occurs on the Khorat Plateau in Thailand and adjacent regions of Laos and Cambodia as well as in south-central *** present data on population size and structure,as well as location,size,compass orientation,and structure of the lizard’s ***,we present climatic data(ambient air temperature and precipitation)at the study site for the duration of our field work as well as temperature data for the complete year ***,we provide data on egg laying,incubation conditions and characteristics of the ***,we present an easy to use and reliable non-invasive method for the long-term recognition of individual butterfly lizards based on their unique dorsal *** lizards are utilized as a food source for the local human *** far,there are no farming projects in Thailand involving this species and all individuals are collected from the wild *** data are available on the population dynamics of *** but it can be assumed that habitat destruction due to land use change as well as its utilization for human consumption have negative effects on the long-term survival of the local populations of this lizard *** baseline data presented here are essential for any meaningful conservation strategy for these lizards.

关键词： Burrow structure butterfly lizard ecology Khorat Plateau Southeast Asia Squamata

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

Influence of Ti Powder Characteristics on Combustion Synthesis of Porous NiTi Alloy

引用

Journal of Materials Science & Technology 2002年第3期18卷 248-250页

作者： YonghuaLI V.E.gunther 等 InstituteofMetalResearch ChineseAcademyofScienceskShenyang110016China ScientificResearchInstituteofMedicalMaterialsandShapeMemoryImplats Tomsk634034Russia

Porous NiTi shape memory alloy (SMA) is a novel biomedical material used for human hard tissue implant. The influence of elemental titanium powder characteristics such as powder morphology, particle size and specific surface area (SSA) on the minimal ignition temperature, combustion temperature and final product of porous NiTi SMA fabricated by combustion synthesis method was investigated in this paper by scanning electron microscopy (SEM) and laser diffraction. The preliminary data indicated that the titanium powder characteristics had a strong effect on combustion synthesis of porous NiTi SMA.

关键词： Porous NiTi shape memory alloy Combustion synthesis Titanium powder characteristics

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

A New Convergent Explicit Tree-Grid Method for HJB Equations in One Space Dimension

引用

Numerical Mathematics(Theory,Methods and Applications) 2018年第1期11卷 1-29页

作者： Igor Kossaczky Matthias Ehrhardt Michael gunther Lehrstuhl fur Angewandte Mathematik und Numerische Analysis Fakultat fur Mathematik und NaturwissenschaftenBergische Universitat WuppertalGaußstrasse 2042119 WuppertalGermany

In this work we introduce a new unconditionally convergent explicit Tree-Grid Method for solving stochastic control problems with one space and one time dimension or equivalently,the corresponding Hamilton-Jacobi-Bellman *** prove the convergence of the method and outline the relationships to other numerical *** case of vanishing diffusion is treated by introducing an artificial diffusion *** illustrate the superiority of our method to the standardly used implicit finite difference method on two numerical examples from finance.

关键词： Tree-Grid Method Hamilton-Jacobi-Bellman equation Stochastic control problem

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

Chemical oxygen demand reduction in coffee wastewater through chemical flocculation and advanced oxidation processes

引用

Journal of Environmental Sciences 2007年第3期19卷 300-305页

作者： ZAYAS Pérez Teresa GEISSLER gunther HERNANDEZ Fernando Postgrade in Environmental Sciences Center of ChemistryInstitute of Science.Meriterious University Autonomous of Puebla.P.O.Box 1613C.P.72000PueblaMexico.

The removal of the natural organic matter present in coffee processing wastewater through chemical coagulation-flocculation and advanced oxidation processes （AOP） had been studied. The effectiveness of the removal of natural organic matter using commercial flocculants and UV/H202, UV/O3 and UV/H2O2/O3 processes was determined under acidic conditions. For each of these processes, different operational conditions were explored to optimize the treatment efficiency of the coffee wastewater. Coffee wastewater is characterized by a high chemical oxygen demand （COD） and low total suspended solids. The outcomes of coffee wastewater treatment using coagulation-flocculation and photodegradation processes were assessed in terms of reduction of COD, color, and turbidity. It was found that a reduction in COD of 67% could be realized when the coffee wastewater was treated by chemical coagulation-flocculation with lime and coagulant T-1. When coffee wastewater was treated by coagulation-flocculation in combination with UV/H2O2, a COD reduction of 86% was achieved, although only after prolonged UV irradiation. Of the three advanced oxidation processes considered, UV/H2O2, UV/O3 and UV/H2O2/O3, we found that the treatment with UV/H2O2/O3 was the most effective, with an efficiency of color, turbidity and further COD removal of 87%, when applied to the flocculated coffee wastewater.

关键词： advanced oxidation processes coagulation-flocculation: coffee wastewater chemical oxygen demand (COD)

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

Biomimetics in Production Organization -A Literature Study and Framework

引用

Journal of Bionic Engineering 2016年第2期13卷 200-212页

作者： Kirsten Reisen Ulrich Teschemacher Michael Niehues gunther Reinhart Institute for Machine Tools and Industrial Management Technische Universitat Miinchen ( TUM) Boltzmannstrafle 15 85748 Garch ing Germany

Biomimetics is an established field in research and industry. Current approaches focus on the use of biological principles in product development, while large potentials have also been identified for transferring organisational principles from nature to production organisation. This study gives a comprehensive overview of existing literature and illustrates that only fragmented research is being conducted at present. In order to enable systematic translation into methods that are available to practitioners, a framework is developed which allows the body of literature to be structured and potential fields not being researched at present to be identified. It also points out that some biological principles receive more attention in research approaches and practical implementation in production organisation than others. Furthermore, correlations between biological principles and principles in production are identified that there have already been successful translations of biomimetic approaches to production organisation. On the other hand, it suggests that there are numerous promising approaches only described in an initial paper that need further research before they can be implemented in practice.

关键词： biomimetics framework production organisation optimization

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

Exchange Rate Regime, Financial Market Bubbles and Long-term Growth in China： Lessons from Japan

引用

China & World Economy 2017年第1期25卷 32-57页

作者： gunther Schnabl Senior fellow Leipzig University Institute for Economic Policy Leipzig.

Since 2014, capital inflows into China have turned into capital outflows, reversing the gradual appreciation path of the renminbi against the US dollar into an erratic depreciation path. The paper explains the current capital ouows by comparing China and Japan with respect to the impact of exchange rate expectations on speculative capital flows. It is argued that both in China and Japan, given benign liquidity conditions in the USA, policy-induced appreciation expectations have generated capital inflows that have contributed to overinvestment and financial market bubbles. The current reversal of capital flows is seen as a signal that the bubble in China has burst. To stabilize growth in China and to discourage speculative capital ouows a fixed exchange rate to the dollar is recommended. Given Japan＇s experience and given that China＇s foreign assets remain high, the depreciation pressure on the Chinese renminbi can be expected to abate.

关键词： China capital controls exchange rate policy Japan rebalancing secular stagnation

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

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：