Time filter

Source Type

Suryatriyastuti M.E.,University Lille1 science et Technologies | Mroueh H.,University Lille1 science et Technologies | Burlon S.,IFSTTAR
Numerical Methods in Geotechnical Engineering - Proceedings of the 8th European Conference on Numerical Methods in Geotechnical Engineering, NUMGE 2014 | Year: 2014

This paper deals with modeling the soil-pile interaction of geothermal piles by taking into account mechanical and cyclic thermal effects. In order to properly model the geothermal piles behavior, plasticity in the soil-pile interface should be considered. A laboratory-developed constitutive law, the Modjoin law, is thus employed in the interface elements due to its potentiality in rendering cyclic phenomena. Numerical simulation is conducted for both a single geothermal pile and a group of geothermal piles in the aim to study the influence of soil confinement and pile head rigidity on the thermally-induced stress in such piles. Over the loading cycles, the results show how cyclic effects can affect axial capacity and bearing capacity of pile foundations. © 2014 Taylor & Francis Group, London.

Duflot D.,University Lille1 science et Technologies | Flament J.-P.,University Lille1 science et Technologies | Heinesch J.,CNRS Institute of Chemistry | Hubin-Franskin M.-J.,CNRS Institute of Chemistry
Chemical Physics Letters | Year: 2010

Ab initio calculations have been carried out in order to assign the bands observed in the carbon and oxygen K-shell spectra of gaseous tetrahydrofuran (THF), measured using inner-shell electron energy loss spectroscopy (ISEELS). The good agreement between the theoretical and the measured spectra allows us to re-assign precisely most of the peaks. The ionisation energies are calculated for the first time and found to be consistent with a quantum defect analysis of the core excitation energies. The calculated spectra for the C2 v, C2 and Cs geometries of the molecule show very small differences. Thus, K-shell spectroscopy cannot be used to solve the controversy on the geometry of THF. © 2010 Elsevier B.V. All rights reserved.

Maj A.M.,University of Lille Nord de France | Maj A.M.,Ecole Nationale Supérieure de Chimie de Lille | Suisse I.,University of Lille Nord de France | Suisse I.,University Lille1 science et Technologies | And 7 more authors.
Tetrahedron Letters | Year: 2012

The asymmetric hydrogenation of a new series of 2-functionalized quinolines has been developed in the presence of in situ generated catalysts obtained from [Ir(cod)Cl] 2/(R)-bisphosphine/I 2 combinations. The enantioselectivity levels were as high as 84-94% ee for the synthesis of 1,2,3,4-tetrahydroquinolines. © 2012 Elsevier B.V. All rights reserved.

Rafeh F.,University Lille1 science et Technologies | Mroueh H.,University Lille1 science et Technologies | Burlon S.,Institute Francais Des Science Et Technology Des Tran Of Lamenagement
Computer Methods and Recent Advances in Geomechanics - Proceedings of the 14th Int. Conference of International Association for Computer Methods and Recent Advances in Geomechanics, IACMAG 2014 | Year: 2015

In the study of underground stabilities in North France, originating from the quarries excavated in the jointed chalk bed, it is necessary to comprehend the behavior of this latter. Discontinuities such as embedded joints and fractures inherently affect the material strength and deformational behavior especially at shallow depths where stresses are low. In this case, the behavior of the jointed chalk is controlled by sliding along the discontinuities. Several continuum models are implemented to consider the influence of joints on the behavior of jointed rock masses. These models almost share the concept of superposition of deformations developed through the joints and the intact rock. However, the range of restrictions and the lack of simplicity in most of these models constitute an obstacle in front of their use in engineering practice. To overcome these drawbacks, an equivalent continuum constitutive model accounting for the critical effect of anisotropy on the behavior of stressed chalk is proposed. In this model, general failure at the level of intact chalk is initially checked, and relevant plastic corrections are applied when failure is detected. Based on the theory of multi-mechanisms for plastic strain, updated stresses are recuperated all over the chalk continuum. Triaxial tests are simulated on models with single and double joints. Comparisons with results based on existing models are illustrated to verify the applicability of the proposed model. Stress-strain responses and failure modes are investigated to describe the strength and deformability behavior of the anisotropic chalk mass. © 2015 Taylor & Francis Group, London.

Chaaban F.,Laue Langevin Institute | Darwishe H.,Laue Langevin Institute | Louche B.,University of Artois | Battiau-Queney Y.,University Lille1 science et Technologies | And 3 more authors.
Environmental Earth Sciences | Year: 2012

The use of geographic information system (GIS) minimizes the effort and improves the efficiency of numerical models. The GIS provides a platform for high capacity collection, management, manipulation, analysis, modeling and display of spatial data. The conceptual model is created using GIS objects including points, arcs and polygons so that it can accurately represent real world condition. According to the research problem, the geographical model is based on Hypergraph Based Data Structure method, and a conceptual data model has been created from which a physical data model was elaborated in ArcGIS9. 3 platform. The groundwater modeling system (GMS) provides a powerful tool for hydrodynamics modeling and it is able to solve complex problems such as the groundwater flow and seawater intrusion. The sand-dune system of Hardelot-Plage (North of France) suffers from a lack of well-developed foredune. This problem is linked to the almost constant saturation of beach sand which is the potential source of dune nourishment. In the south of Hardelot, the coastline is slowly, but constantly retreating. To remedy this situation, a coupling between a GIS and GMS was adopted, in order to find the possible scenarios which could lower the piezometric surface in the concerned area and allow dune nourishment again. The GMS used supports the Modflow-2000 code. A direct approach to designing Modflow finite difference model is tedious and less intuitive, specifically for complex boundary and initial conditions. Therefore, a Modflow model can be developed either using a grid or conceptual model approach. The preparation of input data modeling is tedious and takes a long time. The model created in GMS was calibrated against the historical and observed water level data for 1995-2006. Then a hydrodispersive model (MT3d code in GMS) was launched for evaluating sea-water intrusion. The model was run to generate groundwater and salt concentration scenario during pumping tests. © 2011 Springer-Verlag.

PubMed | CONICET, University of the Littoral Opal Coast and University Lille1 science et Technologies
Type: | Journal: Bulletin of environmental contamination and toxicology | Year: 2016

This study is focused on the removal, accumulation and degradation of three environmental ubiquitous polycyclic aromatic hydrocarbons (PAHs), phenanthrene (PHE), fluoranthene (FLA) and pyrene (PYR), by the marine alga Rhodomonas baltica enriched from the English Channel. After separation, purification and culture in several phases, R. baltica was exposed to PAH concentrations that are frequently encountered in the field in several anthropized environments. The results showed that R. baltica can grow under PAH stress, efficiently remove up to 70% of these compounds from the medium by 216h of culture and selectively bioaccumulate PAHs by their hydrophobicity. Between PHE, FLA and PYR, phenanthrene was the compound with higher degradation rates throughout incubation. The equilibrium partitioning theoretical approach showed that physico-chemical partitioning, rather than active bioconcentration, was the major factor governing the bioaccumulation, outlying a potential application in decontamination processes for this species.

Caradec T.,University Lille1 science et Technologies | Pupin M.,French Institute for Research in Computer Science and Automation | Vanvlassenbroeck A.,University Lille1 science et Technologies | Devignes M.-D.,CNRS Lorraine Research Laboratory in Informatics and its Applications | And 5 more authors.
PLoS ONE | Year: 2014

Nonribosomal peptides represent a large variety of natural active compounds produced by microorganisms. Due to their specific biosynthesis pathway through large assembly lines called NonRibosomal Peptide Synthetases (NRPSs), they often display complex structures with cycles and branches. Moreover they often contain non proteogenic or modified monomers, such as the D-monomers produced by epimerization. We investigate here some sequence specificities of the condensation (C) and epimerization (E) domains of NRPS that can be used to predict the possible isomeric state (D or L) of each monomer in a putative peptide. We show that C- and E- domains can be divided into 2 sub-regions called Up-Seq and Down-Seq. The Up-Seq region corresponds to an InterPro domain (IPR001242) and is shared by C- and E-domains. The Down-Seq region is specific to the enzymatic activity of the domain. Amino-acid signatures (represented as sequence logos) previously described for complete C-and E-domains have been restricted to the Down-Seq region and amplified thanks to additional sequences. Moreover a new Down-Seq signature has been found for Ct-domains found in fungi and responsible for terminal cyclization of the peptides. The identification of these signatures has been included in a workflow named Florine, aimed to predict nonribosomal peptides from NRPS sequence analyses. In some cases, the prediction of isomery is guided by genus-specific rules. Florine was used on a Pseudomonas genome to allow the determination of the type of pyoverdin produced, the update of syringafactin structure and the identification of novel putative products. © 2014 Caradec et al.

Shiroudi A.,Hasselt University | Deleuze M.S.,Hasselt University | Canneaux S.,University Lille1 science et Technologies
Journal of Physical Chemistry A | Year: 2014

The oxidation mechanisms of naphthalene by OH radicals under inert (He) conditions have been studied using density functional theory along with various exchange-correlation functionals. Comparison has been made with benchmark CBS-QB3 theoretical results. Kinetic rate constants were correspondingly estimated by means of transition state theory and statistical Rice-Ramsperger-Kassel-Marcus (RRKM) theory. Comparison with experiment confirms that, on the OH-addition reaction pathway leading to 1-naphthol, the first bimolecular reaction step has an effective negative activation energy around -1.5 kcal mol-1, whereas this step is characterized by an activation energy around 1 kcal mol-1 on the OH-addition reaction pathway leading to 2-naphthol. Effective rate constants have been calculated according to a steady state analysis upon a two-step model reaction mechanism. In line with experiment, the correspondingly obtained branching ratios indicate that, at temperatures lower than 410 K, the most abundant product resulting from the oxidation of naphthalene by OH radicals must be 1-naphthol. The regioselectivity of the OH•-addition onto naphthalene decreases with increasing temperatures and decreasing pressures. Because of slightly positive or even negative activation energies, the RRKM calculations demonstrate that the transition state approximation breaks down at ambient pressure (1 bar) for the first bimolecular reaction steps. Overwhelmingly high pressures, larger than 105 bar, would be required for restoring to some extent (within ∼5% accuracy) the validity of this approximation for all the reaction channels that are involved in the OH-addition pathway. Analysis of the computed structures, bond orders, and free energy profiles demonstrate that all reaction steps involved in the oxidation of naphthalene by OH radicals satisfy Leffler-Hammonds principle. Nucleus independent chemical shift indices and natural bond orbital analysis also show that the computed activation and reaction energies are largely dictated by alterations of aromaticity, and, to a lesser extent, by anomeric and hyperconjugative effects. © 2014 American Chemical Society.

Suryatriyastuti M.E.,University Lille1 science et Technologies | Mroueh H.,University Lille1 science et Technologies | Burlon S.,Institute Francais des science et Technologies des Transports
Computers and Geotechnics | Year: 2014

Unsatisfactory understanding of thermally induced axial stress and mobilized shaft friction in the thermo-active piles has led to a cautious and conservative design of such piles. Despite the fact that the number of construction works using this type of piles has been rapidly increasing since the last 20. years and none of them witnessed any structural damage, the question that still remains is how to overcome the cyclic thermal effects in such piles to optimize the design method. This paper presents a soil-pile interaction design method of an axially loaded thermo-active pile based on a load transfer approach by introducing a proposed t-z cyclic function. The proposed t-z function comprises a cyclic hardening/softening mechanism which is able to count the degradation of the soil-pile capacity during two-way cyclic thermal loading in the thermo-active pile. The proposed t-z function is then compared to a constitutive law of soil-pile interface behavior under cyclic loading, the Modjoin law. Afterwards, numerical analyses of a thermo-active pile located in cohesionless soil are conducted using the two cyclic laws in order to comprehend the response of such pile under combined mechanical and cyclic thermal loads. The behaviors of the pile resulting from the two laws show a good agreement in rendering the cyclic degradation effects. At last, the results permit us to estimate the change in axial stress and shaft friction induced by temperature variations that should be taken into account in the geotechnical design of the thermo-active pile. © 2013 Elsevier Ltd.

Danilo C.,University Lille1 science et Technologies | Danilo C.,Albanova University Center | Vallet V.,University Lille1 science et Technologies | Flament J.-P.,University Lille1 science et Technologies | Wahlgren U.,Albanova University Center
Physical Chemistry Chemical Physics | Year: 2010

The electronic spectra of the 5f2 isoelectronic actinide compounds U4+, NpO2 +, and PuO2 2+ have been investigated theoretically both in gas phase and in solution. In the latter case the solvent was modelled by a saturated first hydration sphere, five water molecules for NpO2 +, and PuO2 2+ and eight for U4+, and a continuum model describing the remaining solvent. The transition energies and oscillator strengths were obtained at the spin-orbit level using the relativistic wave function based multi-configuration methods CASPT2 (complete active space with second-order perturbation theory) and MRCI + DC (Davidson corrected multi-reference configuration interaction), followed by a spin-orbit CI based on a dressed effective spin-orbit Hamiltonian. This study is an attempt to contribute to an enhanced understanding of the electronic structure of tetravalent actinide ions and actinyl(v) and (vi) ions. The spin-orbit MRCI and spin-orbit CASPT2 transitions energies have been compared for the bare ions, leading us to the conclusion that the spin-orbit CASPT2 approach is reasonably accurate and can be used with confidence for the calculation of the hydrated species. The first hydration sphere and the bulk solvent lift degeneracies, but the effect on the transition energies is fairly small for the two actinyl ions, while it is larger, up to several thousands of wave numbers for U4+. The calculations allowed us to make assignments of the experimentally observed absorption spectra for all species. The computed transition energies and intensities compared favourably with experiment. © 2010 the Owner Societies.

Loading University Lille1 science et Technologies collaborators
Loading University Lille1 science et Technologies collaborators