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Numerical stress-deformation analysis of cut-off wall in clay-core rockfill dam on thick overburden

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Water Science and Engineering 2016年第3期9卷 219-226页

作者： Si-hong Liu Liu-jiang Wang Zi-jian Wang erich Bauer College of Water Conservancy and Hydropower Engineering Hohai UniversityNanjing 210098China Zhejiang Design Institute of Conservancy and Hydroelectric Power Hangzhou 310002China Institute of Applied Mechanics Graz University of TechnologyGraz 8010Austria

The cut-off wall in a clay-core rockfill dam built on a thick overburden layer is subjected to a large compressive pressure under the action of the loads such as the dead weight of both the dam and the overburden layer, the frictional force induced by the differential settlement between the cut-off wall and surrounding soils, and the water pressure. Thus, reduction of the stress of the cut-off wall has become one of the main problems for consideration in engineering design. In this paper, numerical analysis of a core rockfill dam built on a thick overburden layer was conducted and some factors influencing the stress-strain behaviors of the cut-off wall were investigated. The factors include the improvement of the overburden layer, the modeling approach for interfacial contact between the cut-off wall and surrounding soils, the modulus of the cut-off wall concrete, and the connected pattern between the cut-off wall and the clay core. The result shows that improving the overburden layer,selecting plastic concrete with a low modulus and high strength, and optimizing the connection between the cut-off wall and the clay core of the dam are effective measures of reducing the deformations and compressive stresses of the cut-off wall. In addition, both the Goodman element and the mud-layer element are suitable for simulating the interfacial contact between the cut-off wall and surrounding soils.

关键词： Overburden layer Core rockfill dam Cut-off wall Numerical analysis Stress and deformation analysis

Calibration and performance of two different constitutive models for rockfill materials

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Water Science and Engineering 2016年第3期9卷 227-239页

作者： Lin-ke Li Zhan-jun Wang Si-hong Liu erich Bauer Institute of Applied Mechanics Graz University of Technology Changjiang Institute of Survey PlanningDesign and Research College of Water Conservancy and Hydropower Engineering Hohai University

In this paper, two different concepts for the constitutive modeling of the mechanical behavior of creep-sensitive rockfill materials are presented. Specifically, the performance of an extended generalized plasticity model proposed by Wang is compared with a simplified version of the hypoplastic constitutive model for weathered rockfill materials proposed by Bauer. Both models can reflect the influence of the mean stress on the incremental stiffness, the peak friction angle, and the dilatancy angle. The so-called solid hardness defined for a continuum description and originally introduced by Bauer is embedded in both models. Hydrochemical, thermal, and mechanical weathering are usually caused by environmental changes and are taken into account in a phenomenological description with an irreversible and time-dependent degradation of the solid hardness. A degradation of the solid hardness is usually accompanied by creep deformation of the stressed rockfill material. It is shown that appropriate modeling of creep deformation requires at least a unified description of the interaction between the time-dependent process of degradation of the solid hardness and the stress state. In this context, the solid hardness can be understood as a key parameter for describing the evolution of the state of weathering of the rockfill material. Particular attention is also paid to the necessary procedure for determining the constitutive constants of the two different constitutive models. Finally, the performance of the two different constitutive models is demonstrated by comparing the results obtained from numerical simulations with experimental data from the creep-sensitive rockfill material.

关键词： Rockfill material Creep Generalized plasticity Hypoplasticity Constitutive model

Hypoplastic constitutive modeling of wetting deformation of weathered rockfill materials

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Frontiers of Structural and Civil Engineering 2010年第1期4卷 78-91页

作者： erich BAUER Zhongzhi FU Sihong LIU Institute of Applied Mechanics Graz University of TechnologyGrazAustria Institute of Hydraulic Structures Hohai UniversityNanjing 210098China

The wetting deformation of weathered rockfill materials has been attracting growing attention from both engineers and *** importance of realistic predictions of wetting deformations for high earth and rockfill dams is a strong motivation to establish a suitable constitutive ***,the hypoplastic constitutive model by Gudehus and Bauer was extended by introducing solid hardness depending on the state of *** extended model takes into account the influence of the current density,the effective stress state,the rate of deformation,and the time dependent process of degradation of the solid *** the present paper,the performance of this model is evaluated by comparing numerical simulations with experiments obtained from a water sensitive rockfill *** particular,triaxial compression paths and creep deformation under deviatoric stress states are ***,the constitutive model proposed is used to study the influence of a degradation of the solid hardness on the long term behavior of a hypothetical fill dam.

关键词： rockfill dams weathered granular materials hypoplasticity solid hardness creep stress relaxation

“When you’re down, stay down”:A lesson for all competitive alpine skiers supported by an ACL rupture measured in vivo

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Journal of Sport and Health Science 2022年第1期11卷 14-20页

作者： Jörg Spöorri erich Müller Josef Kröoll Sports Medical Research Group Department of OrthopaedicsBalgrist University HospitalUniversity of ZurichZurich 8008Switzerland University Centre for Prevention and Sports Medicine Department of OrthopaedicsBalgrist University HospitalUniversity of ZurichZurich 8008Switzerland Department of Sport Science and Kinesiology University of SalzburgHallein-Ri 5400Austria

Background:During an experiment,a ski racer equipped with various measurement devices suffered an anterior cruciate ligament(ACL)rupture in his right *** aim of this study was to describe the underlying injury mechanism from a functional ***:Eight giant slalom turns(i.e.,4 left turns),followed by 1 left turn at which the ACL injury occurred,were recorded by 2 video cameras,electromyography of 4 relevant muscle groups,inertial measurement units to measure knee and hip angles,and pressure insoles to determine ground reaction ***:Due to a loss of balance,the ski racer began to slide sideways at the apex of a left *** sliding,his right(outside)leg was actively abducted upward without touching the *** ski racer then attempted to stand up again by dropping his leg back towards the snow *** end of this dropping was accompanied by a decrease in electromyographic activity in the knee stabilizing *** the inside edge of the outer ski caught the snow surface,a rapidly increasing peak force,knee flexion,and an aggressive sudden activation of the vastus medialis muscle were observed,while biceps femoris and rectus femoris further decreased their activation *** likely resulted in excessive anterior translation of the tibia relative to the femur,causing damage to the ***:Our example emphasizes that ski racers should not get up until they stop ***:“When you’re down,stay down.”

关键词： Alpine skiing Athletes Injury mechanism Injury prevention Knee injuries

Visual analytics for event detection: Focusing on fraud

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Visual Informatics 2018年第4期2卷 198-212页

作者： Roger A.Leite Theresia Gschwandtner Silvia Miksch erich Gstrein Johannes Kuntner Vienna University of Technology Austria sIT Solutions AT Spardat GmbH Austria Erste Group IT International Austria

The detection of anomalous events in huge amounts of data is sought in many *** instance,in the context of financial data,the detection of suspicious events is a prerequisite to identify and prevent attempts to ***,various financial fraud detection approaches have started to exploit Visual Analytics ***,there is no study available giving a systematic outline of the different approaches in this field to understand common strategies but also ***,we present a survey of existing approaches of visual fraud detection in order to classify different tasks and solutions,to identify and to propose further research *** this work,fraud detection solutions are explored through five main domains:banks,the stock market,telecommunication companies,insurance companies,and internal *** selected domains explored in this survey were chosen for sharing similar time-oriented and multivariate data *** this survey,we(1)analyze the current state of the art in this field;(2)define a categorization scheme covering different application domains,visualization methods,interaction techniques,and analytical methods which are used in the context of fraud detection;(3)describe and discuss each approach according to the proposed scheme;and(4)identify challenges and future research topics.

关键词： Visual knowledge discovery Time series data Business and finance visualization Financial fraud detection

Transition Metal Aluminum Boride as a New Candidate for Ambient-Condition Electrochemical Ammonia Synthesis

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Nano-Micro Letters 2020年第5期12卷 106-118页

作者： Yang Fu Peter Richardson Kangkang Li Hai Yu Bing Yu Scott Donne erich Kisi Tianyi Ma Discipline of Chemistry School of Environmental and Life SciencesUniversity of NewcastleCallaghanNSW 2308Australia School of Engineering University of NewcastleCallaghanNSW 2308Australia CSIRO Energy 10 Murray Dwyer CircuitMayfield WestNSW 2304Australia School of Environmental Science and Engineering Fujian Normal UniversityFuzhou 350007FujianPeople’s Republic of China

Achieving more meaningful N2 conversion by reducing the energy input and carbon footprint is now being investigated through a method of N2 fixation instead of the Haber-Bosch ***,the electrochemical N2 reduction reaction(NRR)method as a rising approach currently still shows low selectivity(Faradaic efficiency<10%)and high-energy consumption[applied potential at least-0.2 V versus the reversible hydrogen electrode(RHE)].Here,the role of molybdenum aluminum boride single crystals,belonging to a family of ternary transition metal aluminum borides known as MAB phases,is reported for the electrochemical NRR for the first time,at a low applied potential(-0.05 V versus RHE)under ambient conditions and in alkaline *** to the unique nano-laminated crystal structure of the MAB phase,these inexpensive materials have been found to exhibit excellent electrocatalytic performances(NH3 yield:9.2μg h^-1cm^-2mgcat^-1.,Faradaic efficiency:30.1%)at the low overpotential,and to display a high chemical stability and sustained catalytic *** conjunction,further mechanism studies indicate B and Al as main-group metals show a highly selective affinity to N2 due to the strong interaction between the B 2p/Al 3p band and the N 2p orbitals,while Mo exhibits specific catalytic activity toward the subsequent reduction ***,the MAB-phase catalyst under the synergy of the elements within ternary compound can suppress the hydrogen evolution reaction and achieve enhanced NRR *** significance of this work is to provide a promising candidate in the future synthesis of ammonia.

关键词： MAB phase N2 reduction reaction Electrocatalysis Nanostructure

Beijing 2022 Winter Olympic Games:Commitments to science and public health

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Journal of Sport and Health Science 2022年第1期11卷 1-2页

作者： Yu Liu Barbara E.Ainsworth erich Müller Key Laboratory of Exercise and Health Science of Ministry of Education Shanghai University of SportShanghai 200438China Barbara E.Ainsworth Guest Editor School of KinesiologyShanghai University of SportShanghai 200438China Department of Sport Science and Kinesiology University of SalzburgSalzburg5400Austria

The Beijing 24th 2022 Winter Olympic Games present a unique opportunity to promote the spirit and values of the Olympic Games in relation to their impact on physical activity and global health,sports medicine,and sports *** 2022 Winter Olympic Games mark the 98th year since the first Winter Games were held in Chamonix,France,in *** inaugural Winter Olympic Games sponsored 16 events,and 250 athletes from 16 nations participated.1 In contrast,the Beijing 2022 Winter Olympic Games will sponsor 109 events.

关键词： Winter Games sports

Flavonols Protect Arabidopsis Plants against UV-B Deleterious Effects

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Molecular Plant 2013年第4期6卷 1376-1379页

作者： Julia Emiliani erich Grotewold María Lorena Falcone Ferreyra Paula Casat Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI) Universidad Nacional de Rosario Suipacha 531 2000 Rosario Argentina Center for Applied Plant Sciences The Ohio State University Columbus OH 43210 USA Department of Molecular Genetics The Ohio State University Columbus OH 43210 USA

Dear Editor, Flavonols are synthesized by flavonol synthase （FLS） enzymes （Martens et al., 2010）. These compounds absorb UV-B light in the 280-320-nm region and their concentration increases in plants exposed to environmental abiotic and biotic stresses, including UV-B; consequently, flavonols are thought to act as UV-B filters （Agati et al., 2011）. It has been also suggested that these metabolites function as reactive oxygen species （ROS） scavengers, as they contain an OH- group in the 3-position of the flavonoid skeleton, which allows them to chelate metals, inhibiting the formation of free radicals and ROS accumula- tion, once formed （Agati et al., 2009）. For these reasons, it has been suggested that flavonols play uncharacterized roles in UV responses （Verdan et al., 2011）. Nevertheless, despite the fact that the role of flavonols in UV-B protection has been inferred, the protection conferred by flavonols on the target sites of UV-B-damage has not been directly proven in planta.

关键词： Arabidopsis UV-B Deleterious

Laser back scatter: Limitation to higher repetition rate [kHz] Satellite Laser Ranging system

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Geodesy and Geodynamics 2021年第1期12卷 48-53页

作者： Farhat Iqbal G.Kirchner F.Koidl erich Leitgeb Department of Physics University of SargodhaPakistan Space Research Institute Head of Department Satellite GeodesyAustrian Academy of SciencesLustbuehelstrasse 46A-8042GrazAustria Space Research Institute Engineer at Department Planetary GeodesyAustrian Academy of Sciences HpLustbuehelstrasse 46A-8042GrazAustria Institut für Hochfrequenztechnik Institute of Microwave and Photonic EngineeringGraz University of TechnologyA-8010GrazInffeldgasse 12Austria

Satellite laser ranging(SLR)with higher repetition rate is the recent trend for its various *** backscatter(coincidence between recently transmitted pulses and received pulses near the detector)is found to be a constraint for the repetition rates higher than 20 kHz,due to,overlapping with photons returning from a satellite with the present constellation of most of the SLR *** an overlap occurs at every 75 km satellite distance change at 2 kHz repetition rate,and remains for about 7.5 km;for a 20 kHz system however,it will occur after every 7.5 km and remains for 7.5 km,resulting in constant backscatter overlap e leaving no chance to avoid *** resulting noise is 5 times more than before causing a serious problem in detection and lowers the signal to noise ratio of the overall SLR ***,decreasing energy per shot at higher repetition rates e assuming a constant power laser e the resulting backscatter may decrease fractionally.

关键词： Satellite laser ranging Higher repetition rate Noise Retro reflectors