Search

Your search keyword '"Department of Civil and Environmental Engineering [Singapore]"' showing total 11 results
Start Over Author "Department of Civil and Environmental Engineering [Singapore]"
11 results on '"Department of Civil and Environmental Engineering [Singapore]"'

1. Atmospheric forcing dominates winter Barents-Kara sea ice variability on interannual to decadal time scales

Author

Zhongfang Liu, Camille Risi, Francis Codron, Zhimin Jian, Zhongwang Wei, Xiaogang He, Christopher J. Poulsen, Yue Wang, Dong Chen, Wentao Ma, Yanyan Cheng, Gabriel J. Bowen, State Key Laboratory of Marine Geology [Shanghai], Tongji University, Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Océan et variabilité du climat (VARCLIM), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Department of Civil and Environmental Engineering [Singapore], National University of Singapore (NUS), Department of Earth and Environmental Sciences [Ann Arbor], University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Nansen-Zhu International Research Centre, Institute of Atmospheric Physics [Beijing] (IAP), Chinese Academy of Sciences [Beijing] (CAS)-Chinese Academy of Sciences [Beijing] (CAS), State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Department of Geology and Geophysics, and University of Utah

Subjects
Multidisciplinary, [SDU]Sciences of the Universe [physics], Arctic Regions, Atmosphere, Climate, Oceans and Seas, Ice Cover, Seasons, Time
Abstract

The last two decades have seen a dramatic decline and strong year-to-year variability in Arctic winter sea ice, especially in the Barents-Kara Sea (BKS), changes that have been linked to extreme midlatitude weather and climate. It has been suggested that these changes in winter sea ice arise largely from a combined effect of oceanic and atmospheric processes, but the relative importance of these processes is not well established. Here, we explore the role of atmospheric circulation patterns on BKS winter sea ice variability and trends using observations and climate model simulations. We find that BKS winter sea ice variability is primarily driven by a strong anticyclonic anomaly over the region, which explains more than 50% of the interannual variability in BKS sea-ice concentration (SIC). Recent intensification of the anticyclonic anomaly has warmed and moistened the lower atmosphere in the BKS by poleward transport of moist-static energy and local processes, resulting in an increase in downwelling longwave radiation. Our results demonstrate that the observed BKS winter sea-ice variability is primarily driven by atmospheric, rather than oceanic, processes and suggest a persistent role of atmospheric forcing in future Arctic winter sea ice loss.

Published
2023
Full Text
View/download PDF

2. Numerical simulation of hydrodynamic characteristics and bedload transport in cross sections of two gravel-bed rivers based on one-dimensional lateral distribution method

Author

Chien Pham Van, Vivien P. Chua, Thuyloi University, Unité de modélisation mathématique et informatique des systèmes complexes [Bondy] (UMMISCO), Institut de Recherche pour le Développement (IRD [France-Nord])-Institut de la francophonie pour l'informatique-Université Cheikh Anta Diop [Dakar, Sénégal] (UCAD)-Université Gaston Bergé (Saint-Louis, Sénégal)-Université Cadi Ayyad [Marrakech] (UCA)-Université de Yaoundé I-Sorbonne Université (SU), Department of Civil and Environmental Engineering [Singapore], National University of Singapore (NUS), and Université de Yaoundé I-Institut de la francophonie pour l'informatique-Université Cheikh Anta Diop [Dakar, Sénégal] (UCAD)-Université Gaston Bergé (Saint-Louis, Sénégal)-Université Cadi Ayyad [Marrakech] (UCA)-Sorbonne Université (SU)-Institut de Recherche pour le Développement (IRD [France-Nord])

Subjects
Turbulent diffusion, Stratigraphy, 0207 environmental engineering, Fluvial, Sediment, Geology, 02 engineering and technology, Mechanics, 010501 environmental sciences, 01 natural sciences, Cross section (physics), Flow velocity, [SDU]Sciences of the Universe [physics], Shear stress, River morphology, 020701 environmental engineering, 0105 earth and related environmental sciences, Bed load
Abstract

Accurate evaluation and prediction of bedload transport are crucial in studies of fluvial hydrodynamic characteristics and river morphology. This paper presents a one-dimensional numerical model based on the one-dimensional lateral distribution method (1D-LDM) and six classic bedload transport formulae that can be used to simulate hydrodynamic characteristics and bedload transport discharge in cross sections. Two gravel-bed rivers, i.e. the Danube River located approximately 70 km downstream from Bratislava in Slovakia and the Tolten River in south of Chile are used as examples. In the 1D-LDM, gravity, bed shear stress, turbulent diffusion, and secondary flow are included to allow for accurate predictions of flow velocity and consequently bed shear stress in the cross sections. Six classic formulae were applied to evaluate the non-dimensional bedload transport rate, and the bedload transport discharge through a river cross section is obtained by integrating the bedload transport rate over the width of the cross section. The results show that the root mean square error (RMSE) and mean absolute error (MAE) of velocity and water discharge were less than 8% of the observed magnitude, while the correlation coefficient between model predictions and observations was close to unity. The formulae proposed by Ashida and Michiue (1972), in which particle collision with the bed is taken into account, and by Camenen and Larson (2005), which allows for yielding a non-zero bedload transport rate even when the bed shear stress is smaller than the critical bed shear stress value, appeared to be more appropriate for predicting the observed bedload transport rate in the studied cross sections of two gravel-bed rivers. If non-uniform sediment mixtures were considered, the bedload transport discharge through a cross-section could change considerably by up to 22.5% of the observed magnitude. The relations proposed by Ashida and Michiue (1972) and Egiazaroff (1965) for parameterizing the hiding factor yielded more realistic model predictions in comparison with observations for the measured data set collected for the Tolten River, while the one proposed by Wilcock and Crowe (2003) performs the best for the data set measured for the Danube River.

Published
2020
Full Text
View/download PDF

3. Acceleration of western Arctic sea ice loss linked to the Pacific North American pattern

Author

Gabriel J. Bowen, Zhongwang Wei, Francis Codron, Zhongfang Liu, Sha Li, Xiaogang He, Camille Risi, Dong Chen, Christopher J. Poulsen, State Key Laboratory of Marine Geology [Shanghai], Tongji University, Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Océan et variabilité du climat (VARCLIM), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Department of Civil and Environmental Engineering [Singapore], National University of Singapore (NUS), Department of Earth and Environmental Sciences [Ann Arbor], University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, School of Atmospheric Sciences [Zhuhai], Sun Yat-Sen University [Guangzhou] (SYSU), Chinese Academy of Sciences [Beijing] (CAS), Tsinghua University [Beijing] (THU), University of Utah, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)

Subjects
0301 basic medicine, 010504 meteorology & atmospheric sciences, Science, [SDV]Life Sciences [q-bio], General Physics and Astronomy, 01 natural sciences, General Biochemistry, Genetics and Molecular Biology, Article, 03 medical and health sciences, Downwelling, Sea ice, Arctic climate, Atmospheric science, 0105 earth and related environmental sciences, geography, Multidisciplinary, geography.geographical_feature_category, Greenhouse warming, Advection, General Chemistry, Longwave radiation, Arctic ice pack, 030104 developmental biology, Ocean sciences, Arctic, 13. Climate action, Climatology, Environmental science, human activities, geographic locations
Abstract

Recent rapid Arctic sea-ice reduction has been well documented in observations, reconstructions and model simulations. However, the rate of sea ice loss is highly variable in both time and space. The western Arctic has seen the fastest sea-ice decline, with substantial interannual and decadal variability, but the underlying mechanism remains unclear. Here we demonstrate, through both observations and model simulations, that the Pacific North American (PNA) pattern is an important driver of western Arctic sea-ice variability, accounting for more than 25% of the interannual variance. Our results suggest that the recent persistent positive PNA pattern has led to increased heat and moisture fluxes from local processes and from advection of North Pacific airmasses into the western Arctic. These changes have increased lower-tropospheric temperature, humidity and downwelling longwave radiation in the western Arctic, accelerating sea-ice decline. Our results indicate that the PNA pattern is important for projections of Arctic climate changes, and that greenhouse warming and the resultant persistent positive PNA trend is likely to increase Arctic sea-ice loss., The fastest sea-ice decline has been observed in the western Arctic, but the underlying mechanisms are still unclear. Here, the authors show that the Pacific North American pattern plays an important role in western Arctic sea-ice variability.

Published
2021
Full Text
View/download PDF

4. Homogenizing GPS Integrated Water Vapor Time Series: Benchmarking Break Detection Methods on Synthetic Data Sets

Author

Janusz Bogusz, E. Pottiaux, José Antonio Guijarro, A. Quarello, M. Elias, B. Chimani, Olivier Bock, Tong Ning, Fadwa Alshawaf, R. Van Malderen, S. Zengin Kazancı, Peter Domonkos, Emilie Lebarbier, Mostafa Hoseini, V. Tornatore, Anna Klos, Royal Meteorological Institute of Belgium, Royal Observatory of Belgium [Brussels] (ROB), Military University of Technology, Unaffiliated Researcher, Research Institute of Geodesy, Cartography and Topography, Lantmäteriet (agence gouvernementale suédoise), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), École nationale des sciences géographiques (ENSG), Institut National de l'Information Géographique et Forestière [IGN] (IGN)-Université Gustave Eiffel, Agencia Estatal de Meteorología (AEMet), German Research Centre for Geosciences - Helmholtz-Centre Potsdam (GFZ), Norwegian University of Science and Technology [Trondheim] (NTNU), Norwegian University of Science and Technology (NTNU), Mathématiques et Informatique Appliquées (MIA-Paris), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-AgroParisTech-Université Paris-Saclay, Zentralanstalt für Meteorologie und Geodynamik [Vienna] (ZAMG), Politecnico di Milano [Milan] (POLIMI), Karadeniz Technical University (KTU), European COST Action ES1206 GNSS4SWEC, Polish National Science Centre UMO-2016/21/B/ST10/02353, Belgian Federal Science Policy OfficeEuropean Commission, Faculty of Civil Engineering, Architecture and Geodesy, Split University, HELMHOLTZ CENTRE POTSDAM GFZ GERMAN RESEARCH CENTRE FOR GEOSCIENCES POTSDAM DEU, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Department of Civil and Environmental Engineering [Singapore], National University of Singapore (NUS), Université Paris Nanterre (UPN), and Department of Geomatics Engineering

Subjects
010504 meteorology & atmospheric sciences, lcsh:Astronomy, Computer science, GPS, ERA‐Interim, homogenization, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, [SDU.STU.ME]Sciences of the Universe [physics]/Earth Sciences/Meteorology, Environmental Science (miscellaneous), 010502 geochemistry & geophysics, 01 natural sciences, Homogenization (chemistry), Teknologi: 500 [VDP], lcsh:QB1-991, Break detection methods, Global Positioning System, integrated water vapour, Climate change, Atmosphere and climate, ERA-Interim, break detection, Process engineering, 0105 earth and related environmental sciences, Water vapor, GNSS, business.industry, Technology: 500 [VDP], lcsh:QE1-996.5, Benchmarking, Atmosfære og klima, Synthetic data sets, lcsh:Geology, Klimaendringer, Integrated water vapour, [SDU]Sciences of the Universe [physics], 13. Climate action, General Earth and Planetary Sciences, business
Abstract

We assess the performance of different break detection methods on three sets of benchmark data sets, each consisting of 120 daily time series of integrated water vapor differences. These differences are generated from the Global Positioning System (GPS) measurements at 120 sites worldwide, and the numerical weather prediction reanalysis (ERA‐Interim) integrated wáter vapor output, which serves as the reference series here. The benchmark includes homogeneous and inhomogeneous sections with added nonclimatic shifts (breaks) in the latter. Three different variants of the benchmark time series are produced, with increasing complexity, by adding autoregressive noise of the first order to the white noise model and the periodic behavior and consecutively by adding gaps and allowing nonclimatic trends. The purpose of this “complex experiment” is to examine the performance of break detection methods in a more realistic case when the reference series are not homogeneous. We evaluate the performance of break detection methods with skill scores, centered root mean square errors (CRMSE), and trend differences relative to the trends of the homogeneous series. We found that most methods underestimate the number of breaks and have a significant number of false detections. Despite this, the degree of CRMSE reduction is significant (roughly between 40% and 80%) in the easy to moderate experiments, with the ratio of trend bias reduction is even exceeding the 90% of the raw data error. For the complex experiment, the improvement ranges between 15% and 35% with respect to the raw data, both in terms of RMSE and trend estimations. The research has been undertaken in the framework of the European COST Action ES1206 GNSS4SWEC (GNSS for Severe Weather and Climate monitoring; http://www.cost.eu/COST_Actions/essem/ES1206), which also funded two dedicated workshops on this activity.

Published
2020
Full Text
View/download PDF

5. Assessing the Seismic Behavior of Rammed Earth Walls with an L-Form Cross-Section

Author

Thi-Loan Bui, Hoang-An Le, Mai-Phuong Tran, T.T. Bui, Quoc-Bao Bui, Ton Duc Thang University [Hô-Chi-Minh-City], Mécanique des Matériaux et des Structures (M2S), Géomécanique, Matériaux et Structures (GEOMAS), Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA), University of Transport and Communications [Hanoi] (UTC), Ho Chi Minh City University of Transport, Department of Civil and Environmental Engineering [Singapore], National University of Singapore (NUS), and This research is funded by the Vietnam National Foundation for Science and Technology Development(NAFOSTED) under grant number 107.01-2017.22.

Subjects
seismic performance, Geography, Planning and Development, 0211 other engineering and technologies, TJ807-830, 020101 civil engineering, 02 engineering and technology, Management, Monitoring, Policy and Law, Plasticity, TD194-195, Renewable energy sources, 0201 civil engineering, Rammed earth, Cross section (physics), 021105 building & construction, GE1-350, Environmental effects of industries and plants, Renewable Energy, Sustainability and the Environment, business.industry, [SDE.IE]Environmental Sciences/Environmental Engineering, finite element modeling, Structural engineering, Finite element method, Environmental sciences, dynamic behavior, Formwork, business, rammed earth, Geology
Abstract

International audience; Rammed earth (RE) is a construction material which is made by compacting the soil in a formwork. This material is attracting the attention of the scientific community due to its sustainable characteristics. Among different aspects to be investigated, the seismic performance remains an important topic which needs advanced investigations. The existing studies in the literature have mainly adopted simplified approaches to investigate the seismic performance of RE structures. The present paper adopts a numerical approach to investigate the seismic behavior of RE walls with an L-form cross-section. The 3D FEM model used can take into account the plasticity and damage of RE layers and the interfaces. The model was first validated by an experimental test presented in the literature. Then, the model was employed to assess the seismic performance of a L-form wall of a RE house at different amplitudes of earthquake excitations. Influences of the cross-section form on the earthquake performance of RE walls were also investigated. The results show that the L-form cross-section wall has a better seismic performance than a simple rectangular cross-section wall with similar dimensions. For the L-form cross-section wall, the damage observed concentrates essentially on the connection between two flanges of the wall.

Published
2019
Full Text
View/download PDF

6. Effects of particle size on crushing and deformation behaviors of rockfill materials

Author

Xiang Jiang, Yang Xiao, Minqiang Meng, Zhijun Wu, Qingsheng Chen, Ali Daouadji, School of Civil Engineering (SCE), State Key Laboratory for Geomechanics & Deep Underground Engineering, China University of Mining and Technology (CUMT), Key Laboratory of New Technology for Construction of Cities in Mountain Area (MOE), Chongqing University [Chongqing], State Key Laboratory of Coal Mine Disaster Dynamics and Control, Groupe de Recherche en Géomécanique (GRG), Géomécanique, Matériaux et Structures (GEOMAS), Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA), Department of Civil and Environmental Engineering [Singapore], National University of Singapore (NUS), WuHAN School of Civil Engineering (SCE), and The authors would like to acknowledge the financial support from the 111 Project (Grant No. B13024), the National Science Foundation of China (Grant Nos. 51509024, 51678094 and 51578096), the Fundamental Research Funds for the Central Universities (Grant No. 106112017CDJQJ208848), the Special Financial Grant from the China Postdoctoral Science Foundation (Grant No. 2017T100681), and the State Key Laboratory for GeoMechanics and Deep Underground Engineering, China University of Mining and Technology (Grant No. SKLGDUEK1810).

Subjects
Materials science, 010504 meteorology & atmospheric sciences, 010502 geochemistry & geophysics, 01 natural sciences, Stress (mechanics), Breakage, Rockfill materials, [SPI.GCIV.RISQ]Engineering Sciences [physics]/Civil Engineering/Risques, Composite material, Grain crushing, 0105 earth and related environmental sciences, Weibull distribution, [SPI.GCIV.CD]Engineering Sciences [physics]/Civil Engineering/Construction durable, Weibull modulus, lcsh:QE1-996.5, [SPI.GCIV.GEOTECH]Engineering Sciences [physics]/Civil Engineering/Géotechnique, Compression (physics), Overburden pressure, lcsh:Geology, General Earth and Planetary Sciences, One-dimensional compression, [SPI.GCIV.DV]Engineering Sciences [physics]/Civil Engineering/Dynamique, vibrations, Particle size, Single-particle strength, [SPI.GCIV.STRUCT]Engineering Sciences [physics]/Civil Engineering/Structures, Deformation (engineering), [SPI.GCIV.MAT]Engineering Sciences [physics]/Civil Engineering/Matériaux composites et construction
Abstract

Strength and deformation behaviors of rockfill materials, key factors for determining the stability of dams, pertain strongly to the grain crushing characteristics. In this study, single-particle crushing tests were carried out on rockfill materials with nominal particle diameters of 2.5 mm, 5 mm and 10 mm to investigate the particle size effect on the single-particle strength and the relationship between the characteristic stress and probability of non-failure. Test data were found to be described by the Weibull distribution with the Weibull modulus of 3.24. Assemblies with uniform nominal grains were then subjected to one-dimensional compression tests at eight levels of vertical stress with a maximum of 100 MPa. The yield stress in one-dimensional compression tests increased with decreasing the particle size, which could be estimated from the single-particle crushing tests. The void ratio-vertical stress curve could be predicted by an exponential function. The particle size distribution curve increased obviously with applied stresses less than 16 MPa and gradually reached the ultimate fractal grading. The relative breakage index became constant with stress up to 64 MPa and was obtained from the ultimate grading at the fractal dimension (α=2.7). A hyperbolical function was also found useful for describing the relationship between the relative breakage index and input work during one-dimensional compression tests. Keywords: Grain crushing, Single-particle strength, One-dimensional compression, Rockfill materials, Weibull distribution

Published
2018
Full Text
View/download PDF

7. Zoning of confined aquifers inrush and quicksand in Shanghai region

Author

Kewen Wang, Guangyun Gao, Qingsheng Chen, Xianlin Zhang, Yu-Jun Cui, Shaofeng Yao, Tongji University, Laboratoire Navier (navier umr 8205), École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR), Department of Civil and Environmental Engineering [Singapore], National University of Singapore (NUS), Shanghai Municipal Bureau of Planning and Land Resources, and Shanghai Changkai Geotechnical Engineering Co

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, 0211 other engineering and technologies, Aquifer, 02 engineering and technology, 01 natural sciences, Water inrush, Mining engineering, Quicksand, Vulnerability assessment, Urban planning, Natural hazard, 11. Sustainability, Confined aquifers, [SPI.MECA.MEMA]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Mechanics of materials [physics.class-ph], Earth and Planetary Sciences (miscellaneous), Geologic hazards, 0105 earth and related environmental sciences, Water Science and Technology, Risk assessment, 021110 strategic, defence & security studies, geography, geography.geographical_feature_category, Zoning, Hazard, 6. Clean water, Mapping, 13. Climate action, Geology
Abstract

International audience; Groundwater inrush and quicksand from the underlying aquifers are two typical geological hazards during underground constructions in Shanghai region, China. The objective of this work is to give a zoning study on confined aquifers and quicksand geology in Shanghai region and provide helpful decision-making information for the government, urban planners and designers. The hydrogeological characteristics of the confined aquifers in Shanghai are collected, and two different criteria are then proposed for mapping the aquifers. The characteristics and distribution of the soil stratum, in which quicksand would occur, are then presented, and an index system for quicksand hazard and vulnerability assessment is proposed. Furthermore, the quicksand risk in different zones of Shanghai is evaluated using a semiquantitative approach, and the management zoning is developed by considering the urban planning of Shanghai. The zoning maps of confined aquifers and quicksand risk are obtained, and the high-risk zone can be directly identified from the zoning maps. This is greatly helpful for the future urban planning and underground constructions in Shanghai region. The proposed method for quicksand hazard and vulnerability assessment is also applicable for other cities undergoing geological hazards caused by confined water inrush and quicksand.

Published
2018
Full Text
View/download PDF

8. Microlayer source of oxygenated volatile organic compounds in the summertime marine Arctic boundary layer

Author

Tim Papakyriakou, Emma L. Mungall, John Liggio, Alex K. Y. Lee, Jennie L. Thomas, Megan D. Willis, Michel Gosselin, Jonathan P. D. Abbatt, Jeremy J. B. Wentzell, Marjolaine Blais, Lisa A. Miller, Department of Chemistry [University of Toronto], University of Toronto, Air Quality Processes Research Section, Environment and Climate Change Canada, Department of Civil and Environmental Engineering [Singapore], National University of Singapore (NUS), TROPO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la MER de Rimouski (ISMER), Université du Québec à Rimouski (UQAR), Institute of Ocean Sciences [Sidney] (IOS), Fisheries and Oceans Canada (DFO), Centre for Earth Observation Science [Winnipeg], and University of Manitoba [Winnipeg]

Subjects
010504 meteorology & atmospheric sciences, 010501 environmental sciences, Atmospheric sciences, 01 natural sciences, Sea surface microlayer, Atmosphere, chemistry.chemical_compound, Arctic, Dissolved organic carbon, Sea ice, Sea surface micro layer, 14. Life underwater, Isoprene, 0105 earth and related environmental sciences, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], geography, Multidisciplinary, geography.geographical_feature_category, chemical ionization mass spectrometry, Aerosol, chemistry, Marine boundary layer, 13. Climate action, Environmental chemistry, Physical Sciences, Oxygenated volatile organic compounds, Dimethyl sulfide
Abstract

Summertime Arctic shipboard observations of oxygenated volatile organic compounds (OVOCs) such as organic acids, key precursors of climatically active secondary organic aerosol (SOA), are consistent with a novel source of OVOCs to the marine boundary layer via chemistry at the sea surface microlayer. Although this source has been studied in a laboratory setting, organic acid emissions from the sea surface microlayer have not previously been observed in ambient marine environments. Correlations between measurements of OVOCs, including high levels of formic acid, in the atmosphere (measured by an online high-resolution time-of-flight mass spectrometer) and dissolved organic matter in the ocean point to a marine source for the measured OVOCs. That this source is photomediated is indicated by correlations between the diurnal cycles of the OVOC measurements and solar radiation. In contrast, the OVOCs do not correlate with levels of isoprene, monoterpenes, or dimethyl sulfide. Results from box model calculations are consistent with heterogeneous chemistry as the source of the measured OVOCs. As sea ice retreats and dissolved organic carbon inputs to the Arctic increase, the impact of this source on the summer Arctic atmosphere is likely to increase. Globally, this source should be assessed in other marine environments to quantify its impact on OVOC and SOA burdens in the atmosphere, and ultimately on climate.

Published
2017
Full Text
View/download PDF

9. Incorporation of groundwater pumping in a global Land Surface Model with the representation of human impacts

Author

Pokhrel, Yadu N., KOIRALA, Sujan, Yeh, Pat J. -F, Hanasaki, Naota, Longuevergne, Laurent, Kanae, Shinjiro, Oki, Taikan, Department of Civil and Environmental Engineering [Ann Arbor] (CEE), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Department of Biogeochemical Integration [Jena], Max Planck Institute for Biogeochemistry (MPI-BGC), Max-Planck-Gesellschaft-Max-Planck-Gesellschaft, Department of Civil and Environmental Engineering [Singapore], National University of Singapore (NUS), National Institute for Environmental Studies (NIES), Géosciences Rennes (GR), Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Department of Civil and Environmental Engineering [Tokyo], Tokyo Institute of Technology [Tokyo] (TITECH), Laboratory for Integrated Micro Mechatronics Systems (LIMMS), Centre National de la Recherche Scientifique (CNRS)-The University of Tokyo (UTokyo), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), and The University of Tokyo (UTokyo)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Hydrology, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Water table, Water storage, 0207 environmental engineering, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Aquifer, 02 engineering and technology, Groundwater recharge, 01 natural sciences, 6. Clean water, Hydrology (agriculture), 13. Climate action, Environmental science, Groundwater discharge, 020701 environmental engineering, Groundwater model, Groundwater, 0105 earth and related environmental sciences, Water Science and Technology
Abstract

International audience; Observations indicate that groundwater levels are declining in many regions around the world. Simulating such depletion of groundwater at the global scale still remains a challenge because most global Land Surface Models (LSMs) lack the physical representation of groundwater dynamics in general and well pumping in particular. Here we present an integrated hydrologic model, which explicitly simulates ground-water dynamics and pumping within a global LSM that also accounts for human activities such as irrigation and reservoir operation. The model is used to simulate global water fluxes and storages with a particular focus on groundwater withdrawal and depletion in the High Plains Aquifer (HPA) and Central Valley Aquifer (CVA). Simulated global groundwater withdrawal and depletion for the year 2000 are 570 and 330 km 3 yr 21 , respectively; the depletion agrees better with observations than our previous model result without ground-water representation, but may still contain certain uncertainties and is on the higher side of other estimates. Groundwater withdrawals from the HPA and CVA are 22 and 9 km 3 yr 21 , respectively, which are also consistent with the observations of 24 and 13 km 3 yr 21 . The model simulates a significant decline in total terrestrial water storage in both regions as caused mainly by groundwater storage depletion. Ground-water table declined by 14 cm yr 21 in the HPA during 2003–2010; the rate is even higher (71 cm yr 21) in the CVA. These results demonstrate the potential of the developed model to study the dynamic relation-ship between human water use, groundwater storage, and the entire hydrologic cycle.

Published
2015
Full Text
View/download PDF

10. Infectious diseases and their outbreaks in Asia-Pacific: biodiversity and its regulation loss matter

Author

Serge Morand, Yupin Suputtamongkol, Tan Boon Huan, Mohd Tajuddin Abdullah, Sathaporn Jittapalapong, Animal et gestion intégrée des risques (UPR AGIRs), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), Institut des Sciences de l'Evolution de Montpellier (UMR ISEM), École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre National de la Recherche Scientifique (CNRS)-Institut de recherche pour le développement [IRD] : UR226, Kasetsart University, Department of Parasitology, Faculty of Veterinary Medicine (KU), Kasetsart University, Center of Excellence on Agricultural Biotechnology (AG-BIO/PERDO-CHE), Ministry of Education Thaïland, Siriraj Hospital, Mahidol University, Mahidol University [Bangkok], Universiti Malaysia Sarawak (UNIMAS), Department of Civil and Environmental Engineering [Singapore], National University of Singapore (NUS), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Institut de recherche pour le développement [IRD] : UR226-Centre National de la Recherche Scientifique (CNRS), and Kasetsart University (KU)

Subjects
0106 biological sciences, Epidemiology, Biodiversity, lcsh:Medicine, Population Modeling, L73 - Maladies des animaux, Facteur climatique, Santé publique, 01 natural sciences, Disease Outbreaks, Trees, [SDV.MHEP.MI]Life Sciences [q-bio]/Human health and pathology/Infectious diseases, Organisme nuisible aux animaux, lcsh:Science, 2. Zero hunger, 0303 health sciences, Multidisciplinary, Geography, Ecology, Facteur lié au site, Environnement socioéconomique, Temperature, Facteur du milieu, Population ecology, Infectious Disease Epidemiology, 3. Good health, Épidémiologie, Infectious Diseases, Parasitose, Medicine, P01 - Conservation de la nature et ressources foncières, Biodiversité, L72 - Organismes nuisibles des animaux, Research Article, zoonose, Asia, Distribution géographique, [SDV.BID]Life Sciences [q-bio]/Biodiversity, Biology, Agent pathogène, 010603 evolutionary biology, Communicable Diseases, Microbiology, Vector Biology, 03 medical and health sciences, Humans, Transmission des maladies, 030304 developmental biology, Population Density, Pacific Ocean, Population Biology, lcsh:R, Outbreak, Species diversity, Computational Biology, L70 - Sciences et hygiène vétérinaires - Considérations générales, Oiseau, 15. Life on land, Emerging Infectious Diseases, 13. Climate action, Infectious disease (medical specialty), Maladie infectieuse, Threatened species, Écologie animale, [SDV.SPEE]Life Sciences [q-bio]/Santé publique et épidémiologie, lcsh:Q, Parasitology, Mammifère, Species richness, Infectious Disease Modeling
Abstract

International audience; Despite increasing control measures, numerous parasitic and infectious diseases are emerging, re-emerging or causing recurrent outbreaks particularly in Asia and the Pacific region, a hot spot of both infectious disease emergence and biodiversity at risk. We investigate how biodiversity affects the distribution of infectious diseases and their outbreaks in this region, taking into account socio-economics (population size, GDP, public health expenditure), geography (latitude and nation size), climate (precipitation, temperature) and biodiversity (bird and mammal species richness, forest cover, mammal and bird species at threat). We show, among countries, that the overall richness of infectious diseases is positively correlated with the richness of birds and mammals, but the number of zoonotic disease outbreaks is positively correlated with the number of threatened mammal and bird species and the number of vector-borne disease outbreaks is negatively correlated with forest cover. These results suggest that, among countries, biodiversity is a source of pathogens, but also that the loss of biodiversity or its regulation, as measured by forest cover or threatened species, seems to be associated with an increase in zoonotic and vector-borne disease outbreaks.

Published
2013
Full Text
View/download PDF

11. A Comparison of Microbial Water Quality and Diversity for Ballast and Tropical Harbor Waters.

Author

Ng C, Le TH, Goh SG, Liang L, Kim Y, Rose JB, and Yew-Hoong KG

Subjects
Anti-Bacterial Agents pharmacology, Bacteria drug effects, Bacteria genetics, Bacterial Proteins genetics, Chloramphenicol pharmacology, Cluster Analysis, Drug Resistance, Microbial, Enterococcus drug effects, Enterococcus genetics, Escherichia coli drug effects, Escherichia coli genetics, High-Throughput Nucleotide Sequencing, Principal Component Analysis, RNA, Ribosomal, 16S analysis, RNA, Ribosomal, 16S genetics, Real-Time Polymerase Chain Reaction, Salmonella genetics, Sequence Analysis, DNA, Sulfonamides pharmacology, Trimethoprim pharmacology, Vibrio genetics, Seawater microbiology, Water Quality
Abstract

Indicator organisms and antibiotic resistance were used as a proxy to measure microbial water quality of ballast tanks of ships, and surface waters in a tropical harbor. The survival of marine bacteria in ballast tanks appeared to diminish over longer water retention time, with a reduction of cell viability observed after a week based on heterotrophic plate counts. Pyrosequencing of 16S rRNA genes showed distinct differences in microbial composition of ballast and harbor waters. The harbor waters had a higher abundance of operational taxonomic units (OTUs) assigned to Cyanobacteria (Synechococcus spp.) and α-proteobacteria (SAR11 members), while marine hydrocarbon degraders such as γ-proteobacteria (Ocenspirillaes spp., Thiotrchales spp.) and Bacteroidetes (Flavobacteriales spp.) dominated the ballast water samples. Screening of indicator organisms found Escherichia coli (E. coli), Enterococcus and Pseudomonas aeruginosa (P. aeruginosa) in two or more of the ballast and harbor water samples tested. Vibrio spp. and Salmonella spp. were detected exclusively in harbor water samples. Using quantitative PCR (qPCR), we screened for 13 antibiotic resistant gene (ARG) targets and found higher abundances of sul1 (4.13-3.44 x 102 copies/mL), dfrA (0.77-1.80 x10 copies/mL) and cfr (2.00-5.21 copies/mL) genes compared to the other ARG targets selected for this survey. These genes encode for resistance to sulfonamides, trimethoprim and chloramphenicol-florfenicol antibiotics, which are also known to persist in sediments of aquaculture farms and coastal environments. Among the ARGs screened, we found significant correlations (P<0.05) between ereA, ermG, cfr and tetO genes to one or more of the indicator organisms detected in this study, which may suggest that these members contribute to the environmental resistome. This study provides a baseline water quality survey, quantitatively assessing indicators of antibiotic resistance, potentially pathogenic organisms and a broad-brush description of difference in microbial composition and diversity between open oceans and tropical coastal environments through the use of next generation sequencing technology.

Published
2015
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results