Monteil J.,University of Lyon |
Billot R.,IFSTTAR |
Sau J.,University of Lyon |
Armetta F.,LIRIS Laboratory |
And 2 more authors.
Transportation Research Record | Year: 2013
As cooperative systems (connected vehicles) enable communication and the exchange of information between vehicles and infrastructure, the communication capabilities are expected to lead to better active traffic management on urban motorways. Technological constraints must be the basis for any management strategy. If communication has been analytically proved to help stabilize traffic flow at a microscopic level, then realistic communication strategies should be evaluated by taking into consideration multiple perturbations such as sensor faults and driver cooperation. In this study, a three-layer multiagent framework was used to model and control the homogenization of traffic flow. The physical layer coordinated vehicle dynamics on the basis of a cooperative car-following model. This layer included cooperation derived from the communication and trust layers that, respectively, managed information and its reliability. Simulation results highlight the positive impacts of communication and control on the stability of traffic flow.
Le T.D.,LNCC |
Murad M.A.,LNCC MCT |
Pereira P.A.,LNCC |
Boutin C.,ENTPE |
And 2 more authors.
Society of Petroleum Engineers - SPE Reservoir Simulation Symposium 2015 | Year: 2015
In this paper we construct coupled gas flow models in shale-matrix and hydraulic fractures within the framework of the reiterated homogenization procedure in conjunction with the treatment of fractures as (n-1) interfaces (n = 2, 3) and adsorption isotherm of Langmuir-based monolayer model in the nanopores. At the nanoscale the Langmuir model is applied to reconstruct general monolayer adsorption isotherms of pure methane in the intra-particle porosity of the gas-wet organic matter. The nanoscopic model is upscaled to the microscale where kerogen particles and nanopores are viewed as overlaying continua forming the organic aggregates at thermodynamic equilibrium with the free gas in the water partially saturated interparticle pores. The reaction/diffusion equation for pure gas movement in the kerogen aggregates is coupled with both Fickian diffusion of dissolved gas in water and Darcy free gas flow in the interparticle pores also lying in the vicinity of the inorganic solid phase (clay, quartz, calcite) assumed impermeable. By postulating continuity of fugacity between free and dissolved gas in the interparticle pores and neglecting the bound water movement, we upscale the microscopic problem to the mesoscale, where organic and inorganic matter, and interparticle pores are homogenized. The upscaling gives rise to a new nonlinear pressure equation for gas hydrodynamics in the interparticle pores including a new storage parameter dependent on the total carbon content (TOC) and porosities. The new pressure equation in the shale matrix is coupled with single phase gas flow in the hydraulic fractures. The reduction of dimensionality method is applied to treat fractures as interfaces by averaging the flow equation across the fracture aperture. Combination of the methods give rise to a new matrix/fracture coupled problem. Numerical simulations illustrate the potential of the multiscale approach proposed for computing gas production curves and recovery factor in different gas flow regimes. Copyright © 2015 Society of Petroleum Engineers.
Blanc P.,Bureau de Recherches Géologiques et Minières |
Lassin A.,Bureau de Recherches Géologiques et Minières |
Piantone P.,Bureau de Recherches Géologiques et Minières |
Azaroual M.,Bureau de Recherches Géologiques et Minières |
And 3 more authors.
Applied Geochemistry | Year: 2012
The development of Thermoddem, a thermodynamic database devoted to geochemical modelling for environmental studies in general and, more specifically, to chemical systems involving waste materials, is discussed here. Concerns are also focused on taking into account some specific needs for modellers by proposing different output formats and some important information concerning the solid phases, the transformation path, paragenesis and insights into crystallographic details. This additional information aims to avoid considering phases that may not be "active" under current environmental conditions. The database is especially devoted to environmental applications, ranging from waste material management to pollutant behaviour, including the context of deep underground disposal. Selection rules and conventions are illustrated through the example of the Fe-water system, while a second example details the relationships between low and high ionic strength media, from the point of view of thermodynamic databases. Technical aspects concerning the development of a management information system for Thermoddem and its availability on the web (http://thermoddem.brgm.fr) are also provided. © 2012 Elsevier Ltd.
Janin A.,University of Lyon |
Lena J.-P.,University Claude Bernard Lyon 1 |
Deblois S.,ENTPE |
Joly P.,French National Center for Scientific Research
Conservation Biology | Year: 2012
The influence of landscape matrix on functional connectivity has been clearly established. Now methods to assess the effects of different land uses on species' movements are needed because current methods are often biased. The use of physiological parameters as indicators of the level of resistance to animal movement associated with different land uses (i.e., matrix resistance) could provide estimates of energetic costs and risks to animals migrating through the matrix. To assess whether corticosterone levels indicate matrix resistance, we conducted experiments on substrate choice and measured levels of corticosterone before and after exposure of toads (Bufo bufo) to 3 common substrates (ploughed soil, meadow, and forest litter). We expected matrix resistance and hormone levels to increase from forest litter (habitat of the toad) to meadows to ploughed soil. Adult toads had higher corticosterone levels on ploughed soil than on forest litter or meadow substrates. Hormone levels did not differ between forest litter and meadow. Toads avoided moving onto ploughed soil. Corticosterone levels in juvenile toads were not related to substrate type; however, hormone levels decreased as humidity increased. Juveniles, unlike adults, did not avoid moving over ploughed soil. The difference in responses between adult and juvenile toads may have been due to differences in experimental design (for juveniles, entire body used to measure corticosterone concentration; for adults, saliva alone); differences in the scale of sensory perception of the substrate (juveniles are much smaller than adults); or differences in cognitive processes between adult and juvenile toads. Adults probably had experience with different substrate types, whereas juveniles first emerging from the water probably did not. As a consequence, arable lands could act as ecological traps for juvenile toads. © 2012 Society for Conservation Biology.
Goore Bi E.,University of Québec |
Monette F.,University of Québec |
Gachon P.,University of Quebec at Montréal |
Gasperi J.,University Paris Est Creteil |
Environmental Science and Pollution Research | Year: 2015
Projections from the Canadian Regional Climate Model (CRCM) for the southern part of the province of Québec, Canada, suggest an increase in extreme precipitation events for the 2050 horizon (2041–2070). The main goal of this study consisted in a quantitative and qualitative assessment of the impact of the 20 % increase in rainfall intensity that led, in the summer of 2013, to overflows in the “Rolland-Therrien” combined sewer system in the city of Longueuil, Canada. The PCSWMM 2013 model was used to assess the sensitivity of this overflow under current (2013) and future (2050) climate conditions. The simulated quantitative variables (peak flow, QCSO, and volume discharged, VD) served as the basis for deriving ecotoxicological risk indices and event fluxes (EFs) transported to the St. Lawrence (SL) River. Results highlighted 15 to 500 % increases in VD and 13 to 148 % increases in QCSO by 2050 (compared to 2013), based on eight rainfall events measured from May to October. These results show that (i) the relationships between precipitation and combined sewer overflow variables are not linear and (ii) the design criteria for current hydraulic infrastructure must be revised to account for the impact of climate change (CC) arising from changes in precipitation regimes. EFs discharged into the SL River will be 2.24 times larger in the future than they are now (2013) due to large VDs resulting from CC. This will, in turn, lead to excessive inputs of total suspended solids (TSSs) and tracers for numerous urban pollutants (organic matter and nutrients, metals) into the receiving water body. Ecotoxicological risk indices will increase by more than 100 % by 2050 compared to 2013. Given that substantial VDs are at play, and although CC scenarios have many sources of uncertainty, strategies to adapt this drainage network to the effects of CC will have to be developed. © 2015, Springer-Verlag Berlin Heidelberg.
He Y.,University of Western Sydney |
Kwok K.,University of Western Sydney |
Meroney R.,Colorado State University |
Ly J.,University of Western Sydney |
12th Americas Conference on Wind Engineering 2013, ACWE 2013: Wind Effects on Structures, Communities, and Energy Generation | Year: 2013
Presented in this paper are the results of numerical simulation of bushfire enhanced wind and its impact on buildings of various shapes. Using an extended computation domain, the velocity and pressure fields around three buildings which are exposed to wind and bushfire attacks were investigated. Apart from the building shape and orientation, the bushfire intensity is also a control parameter which was varied in the investigation. The results revealed that bushfires can enhance wind and produce greater impact on building structures. The pressure coefficient was found to increase proportionally with increasing bushfire intensity. An L-shaped building in a longitudinal orientation along with the wind direction was able to create a wedge effect to alleviate the wind load.
Osselin F.,Laboratoire Navier |
Fen-Chong T.,Laboratoire Navier |
Fabbri A.,ENTPE |
Dangla P.,Laboratoire Navier |
And 2 more authors.
International Workshop on Geomechanics and Energy: The Ground as Energy Source and Storage | Year: 2013
The aim of this study is to evaluate the mechanical effects of the in-pore crystallization of salts during injection of supercritical carbon dioxide in the context of CCS. Isotropic linear poroelasticity modeling has been used to predict the macroscopic equivalent tensile stress in two cases: a REV linked to an infinite resrevoir of constant concentration, and an isolated REV subjected to an injection of dry supercritical carbon dioxide. Results show that crystallization pressure cannot be neglected while calculating the mechanical behavior of an aquifer during CCS.
Le Nouveau N.,Certu |
Deroubaix J.-F.,ParisTech National School of Bridges and Roads |
Diou G.,ENTPE |
Tardivo B.,Ministere de lEcologie
Techniques - Sciences - Methodes | Year: 2013
In France, since 2011, local authorities have had the possibility to establish a fee for the stormwater management. The introduction of this fee is likely to enable them on one hand to encourage to sealing and stormwater source control and on the other hand to obtain resources to address the challenges of public stormwater management financing. Its input is a priori a milestone in the construction of a public stormwater management service. It is also a special moment to question it from the management of public finances in terms of policy choices, financial constraints and capacity for action. So, a study was initiated to observe and analyze the conditions of entry of this new instrument. Some municipalities have already deliberated to implement it; a number are considering whether to do so. After recalling the construction of this fee in France, a first overview of the conditions of its introduction by municipalities is raised. It helps to understand what taxation reveals about public action in the field of stormwater management today.
Leo C.J.,University of Western Sydney |
Wong H.K.,ENTPE |
Liyanapathirana S.,University of Western Sydney
AIP Conference Proceedings | Year: 2010
This paper describes an updated and simple EPS constitutive model proposed by the authors for modelling EPS geofoam in geotechnical applications where geofoam-structure as well as geofoam-soil interactions occur. The work is based on an earlier model developed by the authors, which has since been modified to reflect recent experimental results suggesting the admissibility of the Drucker-Prager failure criterion in lieu of the Mohr-Coulumb criterion. The updated model is developed within the framework of classical elasto-plasticity, with the inclusion of strain hardening, a hardening rule defined in terms of equivalent deviatoric plastic strain and a non-associate flow rule. It is simple to calibrate (with 6 independent parameters determined from triaxial tests) and is relatively easy to incorporate into numerical codes. The updated model has been calibrated against results from a series of "drained" triaxial tests performed on the EPS geofoam. The steps required for calibration are described in the paper. It has been also been shown to accurately reproduce the responses of the material under shearing, in particular, of the shear-contraction post yield behaviour typical of geofoam material. The model will be applicable for a variety of geotechnical applications such as for the modelling of EPS geofoam inclusion behind retaining structures and as a buffer material to mitigate against dynamic loading and vibrations. © 2010 American Institute of Physics.
Villa C.,ENTPE |
Lighting Research and Technology | Year: 2013
We developed a web application to investigate online-based experiments for the psychovisual assessment of luminous environments. We reproduced online a laboratory experiment conducted in a virtual environment, in which the luminous environment of an office room lit by different combinations of ambient/task lighting was assessed by observers. A control panel of 30 observers performed both experiments. Statistical analyses revealed no statistically significant differences between data collected in the laboratory and online. In addition, an online-based experiment involving 1114 observers was conducted to study the uncontrolled experimental conditions that may impact results. We show that, by increasing the panel size, bias, mainly related to the perceived contrast and brightness of the display and the brightness of the surrounding area is removed. Findings suggest that 100 observers are enough to remove bias. © The Chartered Institution of Building Services Engineers 2012.