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[Departement_IRSTEA]Eaux [TR1_IRSTEA]ARCEAU; International audience; The effect of subsurface drainage on agricultural catchment outflow has been debated for quite some time. Concerning downstream peak flow, it is a complex task to predict the impact of agricultural drainage because different flow media are involved: the soil, pipe drainage networks and open channel networks. In France, drain pipes are designed to operate under a free-surface flow condition. Nevertheless, during intense rainfall events, some pipe sections may flow under pressurised conditions, so that a complex interaction between pipe networks and groundwater flows appears in the vicinity of these sections. In this paper, an integrated modelling strategy is considered in order to analyse these flow interactions. A 10 Saint-Venant network model is combined with a 2D Boussinesq shallow groundwater flow model by means of special internal boundary conditions which take into account the flow interactions. This study follows field experiments conducted in a small subsurface drained catchment, where drainage discharge and pressure heads were monitored in a buried pipe collector and water table profiles were monitored in the field. The simulation results of the coupled model are in good agreement with experimental observations. Moreover, it satisfactorily simulates the behaviour of the drainage system during the pressurisation stages. The model is also applied to a scenario addressing the effect of pressurisation, as compared to non-pressurisation, at the outlet. The coupled model reveals the relation existing between pipe pressurisation and hydrograph timing. Pipe pressurisation results in temporary storage of discharging water, which is released later when pressurisation stops. (c) 2014 Published by Elsevier B.V.

This article attempts to explore the user-producer interaction in the online community of Habbo Hotel. Based on desk research, interviews, an online survey among more than 3000 Habbo Hotel users in The Netherlands and online discussion groups with 45 Habbos, three specific issues that illustrate the interactions between the users and producers are highlighted. First, different levels of user-generated content in Habbo Hotel will be discussed. Second, the communication between the users and producers will be analysed and, finally, the matter of online safety will be reviewed. Copyright © 2009, Inderscience Publishers.

Second order Møller–Plesset perturbation theory at the complete basis set limit and diffusion quantum Monte Carlo are used to examine several low energy isomers of the water hexamer. Both approaches predict the so-called prism to be the lowest energy isomer, followed by cage, book, and cyclic isomers. The energies of the four isomers are very similar, all being within 10–15 meV/H2O. These reference data are then used to evaluate the performance of several density-functional theory exchange-correlation (xc) functionals. A subset of the xc functionals tested for smaller water clusters [I. Santra et al., J. Chem. Phys. 127, 184104 (2007)] has been considered. While certain functionals do a reasonable job at predicting the absolute dissociation energies of the various isomers (coming within 10–20 meV/H2O), none predict the correct energetic ordering of the four isomers nor does any predict the correct low total energy isomer. All xc functionals tested either predict the book or cyclic isomers to have the largest dissociation energies. A many-body decomposition of the total interaction energies within the hexamers leads to the conclusion that the failure lies in the poor description of van der Waals (dispersion) forces in the xc functionals considered. It is shown that the addition of an empirical pairwise (attractive) C6R−6 correction to certain functionals allows for an improved energetic ordering of the hexamers. The relevance of these results to density-functional simulations of liquid water is also briefly discussed.

In this paper, we study the Dzyaloshinskii-Moriya (DM) anisotropic XX spin-chain model in the presence of an external homogeneous magnetic field. We found that the Berry phase of the system varies interestingly with small and large amounts of DM interaction and the magnetic field. In addition, we also considered the concurrence (i.e., the amount of entanglement) of the system, and the relationship between the concurrence and the Berry phase. Finally, we calculate the Berry phase of thermal states and verify that the results are consistent with that of the pure states., A*Star Grant No. 012-104-0040 and by the National Research Foundation & Ministry of Education, Singapore

Resonant Two Photon Ionization (R2PI) spectroscopy has been applied to the study of host-guest interactions in molecular clusters formed by supersonic exspansion. Here, the results of R2PI spectroscopy of the fluorinated organic molecules para and ortho-fluoro-sec-butylbenzene and their complexes with water and argon are reported and discussed. In particular, it is shown that the position of the fluorine atom on the aromatic ring influences the formation of different kind of complexes (sigma versus pi) with argon and water. Ab initio calculations were performed to get insight into the molecular shape and the structure of these clusters.

A test bed has been developed in which participants are tasked to work in simulated, scenario based, projects in which face-to-face and remote meetings of about 45 minutes have to be held. Measures on performance, team factors and remote aspects are automatically collected with electronic questionnaires. The sensitivity and reliability of these questionnaires are positively evaluated. The test bed is now ready to be used for evaluating how well meeting assistants support collocated meetings and videoconferencing. © 2008 Springer-Verlag Berlin Heidelberg.

The finding that cytochrome c (cyt c) plays a role in programmed cell death after its release from the mitochondrion has recently renewed interest in this protein. The structural changes in cytochrome c observed at early stages of the apoptotic process have been related to changes occurring in the protein when it forms a complex with phospholipid vesicles. Among the lipids constituting the membrane, cardiolipin is the one thought to bind to cyt c. In this paper, we have investigated the influence exerted by ionic strength on cytochrome c-cardiolipin interaction and found that formation of the cytochrome c-cardiolipin complex occurs via two distinct transitions, implying a high-affinity site and a low-affinity site. Ionic strength significantly influences complex stability; sodium chloride dissociates the complex through two distinct transitions, the second of which occurs at a very high anion concentration. ATP also dissociates the complex, but under the conditions that were investigated, its action is limited to the high-affinity site. The dissociation process is characterized by a very slow kinetic rate constant ( k obs = 4.2 x 10 (-3) s (-1)) and requires several minutes to be completed. We ascribe it to the high activation barrier met by the protein when restoring the native Fe(III)-M80 axial bond. The peroxidase activity shown by cardiolipin-bound cytochrome c is indicative of a less packed protein tertiary conformation in the complex. In line with earlier reports, these data highlight the manifold functions of cytochrome c besides the well-known role it plays in oxidative phosphorylation, shedding more light on the properties of the cytochrome c-cardiolipin complex, involved in the progression of early stages of apoptosis.

Tactile and haptic interaction is becoming increasingly important and is no longer restricted to assistive technologies and special purpose computing environments. The technology has gone through numerous breakthroughs and replications and is now entering a period of developing empiricism, the phase in which the first benefits of this new development are becoming available. While considerable research exists, the current lack of ergonomic standards results in systems without sufficient concerns for either ergonomics or interoperability, leading to difficulties for users of multiple, incompatible or conflicting applications. ISO (through working group TC159/SC4/WG9) is working toward international standards, which are being dual-tracked as both ISO and CEN standards. This paper gives an update on the status of the Draft International Standard on tactile/haptic interactions and the recently initiated work on a framework for tactile/haptic interactions. © 2008 Springer-Verlag Berlin Heidelberg.

A test bed has been developed in which participants are tasked to work in simulated, scenario based, projects in which face-to-face and remote meetings of about 45 minutes have to be held. Measures on performance, team factors and remote aspects are automatically collected with electronic questionnaires. The sensitivity and reliability of these questionnaires are positively evaluated. The test bed is now ready to be used for evaluating how well meeting assistants support collocated meetings and videoconferencing. © 2008 Springer-Verlag Berlin Heidelberg.

Laughter is a highly variable signal, which can be caused by a spectrum of emotions. This makes the automatic detection of laughter a challenging, but interesting task. We perform automatic laughter detection using audio-visual data from the AMI Meeting Corpus. Audio-visual laughter detection is performed by fusing the results of separate audio and video classifiers on the decision level. This results in laughter detection with a significantly higher AUC-ROC than single-modality classification. © 2008 Springer-Verlag Berlin Heidelberg.

Cataloged from PDF version of article. We report use of nonlinear tip-sample interactions to parametrically convert the frequency components of periodic tip-sample interaction forces to frequencies where they can be resonantly detected. One flexural mode of a cantilever is used for tapping-mode imaging and another flexural mode is used for detection of forces converted in presence of an externally injected mechanical oscillation at the difference frequency of the detecting mode and a harmonic of the tapping mode. Material contrast in attractive and repulsive regimes are demonstrated on samples with polymethyl methacrylate patterns and with deoxyribonucleic acid strands on silicon. Parametrically coupled multiharmonic force imaging - ResearchGate. Available from: http://www.researchgate.net/publication/234925290_Parametrically_coupled_multiharmonic_force_imaging [accessed Aug 28, 2015].

Tactile and haptic interaction is becoming increasingly important and is no longer restricted to assistive technologies and special purpose computing environments. The technology has gone through numerous breakthroughs and replications and is now entering a period of developing empiricism, the phase in which the first benefits of this new development are becoming available. While considerable research exists, the current lack of ergonomic standards results in systems without sufficient concerns for either ergonomics or interoperability, leading to difficulties for users of multiple, incompatible or conflicting applications. ISO (through working group TC159/SC4/WG9) is working toward international standards, which are being dual-tracked as both ISO and CEN standards. This paper gives an update on the status of the Draft International Standard on tactile/haptic interactions and the recently initiated work on a framework for tactile/haptic interactions. © 2008 Springer-Verlag Berlin Heidelberg.

A multiscale formulation is derived for the mechanics of a dilute fiber network microstructure, as occurs in in vitro reconstituted collagen gels, to accommodate the deterministic solution of a uniform-stress condition in the fiber network. The macroscale two-phase equations are derived based on the integral volume-averaging approach of the spatial averaging theorem, modified for the averaging volume to deform materially in the solid phase and thereby ensuring consistent network mass conservation. For low-Reynolds-number fiber-fluid interaction with no hydrodynamic interaction between fibers, the macroscale Darcy law arises naturally as a function of average fiber orientation and volume fraction, with no additional empirical specification. The macroscale equations are solved using finite element analysis with the averaging volumes centered at Gauss points of integration. The macroscale solid stress and fluid velocity are obtained by microscale deterministic solution of network and Stokesian mechanics within the averaging volume at each Gauss point, whereas the macroscale displacements and fluid pressure are solved as interpolated finite element field variables. The theory when applied to describe confined compression of collagen gels reproduced the strain-rate dependent behavior observed in poroelastic materials. The deformation of the averaging region and the reorientation of the collagen network in response to strain are also discussed. © 2008 Society for Industrial and applied Mathematics. 7 22 43 22-43

A solid hybrid molecular material containing 1-butyl 3-methyl imidazolium cations and Keggin anions of phosphotungstic acid has been synthesized. It is fully characterized by CHN analysis, FTIR, XRD, UV-Vis-NIR DRS, 31P MAS NMR, TGA and SEM. The FTIR spectrum of the compound shows the fingerprint vibrational bands of both Keggin molecular anions and imidazolium cations. The aromatic C-H stretch region (2700-3250 cm-1) of imidazolium cation is split due to the interaction between the ring C-H and bulky Keggin anion. The red-shift in the UV-Vis spectra and the downfield 31P MAS NMR chemical shift also confirm the electrostatic interaction between the ions in the compound. Near IR spectral region (1000-2500 nm) shows the elimination of water in the compound which is hydrophobic. � Indian Academy of Sciences.

A novel continuous time fluid flow model of the dynamics of the interaction between ACK-clocking and the link buffer is presented.. A fundamental integral equation relating the instantaneous flow rate and the window dynamics is derived. Properties of the model, such as well-posedness and stability, are investigated. Packet level experiments verily that this new model is more accurate than existing models, correctly predicting qualitatively different behaviors, for example when round trill delays are heterogeneous. QC 20110114

Learning a process control task, such as tactical picture compilation in the Navy, is difficult, because the students have to spend their limited cognitive resources both on the complex task itself and the act of learning. In addition to the resource limits, motivation can be reduced when learning progress is slow. Intelligent Virtual Agents may help to improve tutoring systems by offering a student feedback on their performance via speech and facial expression, which imposes limited "communication load" and motivating ways of interaction. We present our Intelligent Virtual Agent, called Ashley, and an experiment in which we examined whether learning of tactical picture compilation is better when the feedback is provided by Ashley compared to a standard text-box interface. This first experiment did not show user interface effects, but provided new requirements for the next version of the feedback system and Ashley: The task to learn was yet too simple for substantial feedback effects, and the timing of Ashley's feedback should be improved, and Ashley's presence should be better scheduled. © 2008 Springer-Verlag Berlin Heidelberg.

We developed acoustic and lexical classifiers, based on a boosting algorithm, to assess the separability on arousal and valence dimensions in spontaneous emotional speech. The spontaneous emotional speech data was acquired by inviting subjects to play a first-person shooter video game. Our acoustic classifiers performed significantly better than the lexical classifiers on the arousal dimension. On the valence dimension, our lexical classifiers usually outperformed the acoustic classifiers. Finally, fusion between acoustic and lexical features on feature level did not always significantly improve classification performance. © 2008 Springer-Verlag Berlin Heidelberg.

We developed acoustic and lexical classifiers, based on a boosting algorithm, to assess the separability on arousal and valence dimensions in spontaneous emotional speech. The spontaneous emotional speech data was acquired by inviting subjects to play a first-person shooter video game. Our acoustic classifiers performed significantly better than the lexical classifiers on the arousal dimension. On the valence dimension, our lexical classifiers usually outperformed the acoustic classifiers. Finally, fusion between acoustic and lexical features on feature level did not always significantly improve classification performance. © 2008 Springer-Verlag Berlin Heidelberg.

Learning a process control task, such as tactical picture compilation in the Navy, is difficult, because the students have to spend their limited cognitive resources both on the complex task itself and the act of learning. In addition to the resource limits, motivation can be reduced when learning progress is slow. Intelligent Virtual Agents may help to improve tutoring systems by offering a student feedback on their performance via speech and facial expression, which imposes limited "communication load" and motivating ways of interaction. We present our Intelligent Virtual Agent, called Ashley, and an experiment in which we examined whether learning of tactical picture compilation is better when the feedback is provided by Ashley compared to a standard text-box interface. This first experiment did not show user interface effects, but provided new requirements for the next version of the feedback system and Ashley: The task to learn was yet too simple for substantial feedback effects, and the timing of Ashley's feedback should be improved, and Ashley's presence should be better scheduled. © 2008 Springer-Verlag Berlin Heidelberg.

Laughter is a highly variable signal, which can be caused by a spectrum of emotions. This makes the automatic detection of laughter a challenging, but interesting task. We perform automatic laughter detection using audio-visual data from the AMI Meeting Corpus. Audio-visual laughter detection is performed by fusing the results of separate audio and video classifiers on the decision level. This results in laughter detection with a significantly higher AUC-ROC than single-modality classification. © 2008 Springer-Verlag Berlin Heidelberg.

Date of Conference: 28-31 Oct. 2007 Conference name: 2007 IEEE Ultrasonics Symposium Proceedings In this paper, we present how a capacitive micromachined ultrasonic transducer (cMUT) couples to the immersion medium, based on an accurate parametric model. We show that the velocity of cMUT membrane can be written as a sum of an average velocity term and a residual term. We demonstrate that this residual term carries non-zero energy at the parallel resonance frequency by investigating the interaction between the cMUT cell and a liquid medium. We develop a model that is also applicable around the parallel resonance frequency. © 2007 IEEE.

Two numerical methods are presented for the periodic initial-value problem of the long wave-short wave interaction equations describing the interaction between one long longitudinal wave and two short transverse waves propagating in a generalized elastic medium. The first one is the relaxation method, which is implicit with second-order accuracy in both space and time. The second one is the split-step Fourier method, which is of spectral-order accuracy in space. We consider the first-, second- and fourth-order versions of the split-step method, which are first-, second- and fourth-order accurate in time, respectively. The present split-step method profits from the existence of a simple analytical solution for the nonlinear subproblem. We numerically test both the relaxation method and the split-step schemes for a problem concerning the motion of a single solitary wave. We compare the accuracies of the split-step schemes with that of the relaxation method. Assessments of the efficiency of the schemes show that the fourth-order split-step Fourier scheme is the most efficient among the numerical schemes considered. Publisher's Version Q1 WOS:000244797300006

This present paper describes three dimensional computational analysis of complex internal flow in a cross flow fan. A commercial computational fluid dynamics (CFD) software code CFX was used for the computation. RNG k-� two equation turbulence model was used to simulate the model with unstructured mesh. Sliding mesh interface was used at the interface between the rotating and stationary domains to capture the unsteady interactions. An accurate assessment of the present investigation is made by comparing various parameters with the available experimental data. Three impeller geometries with different blade angles and radius ratio are used in the present study. Maximum energy transfer through the impeller takes place in the region where the flow follows the blade curvature. Radial velocity is not uniform through blade channels. Some blades work in turbine mode at very low flow coefficients. Static pressure is always negative in and around the impeller region.

The occurrence of reverse flow in a channel when an obstruction is placed at the entry is already known. In this article an attempt is made to bring out the mechanism that governs this phenomenon. Flow visualisation and pressure measurements are employed for this purpose. The obstruction at the front end of the channel is essential for triggering the reverse flow. For reverse, stagnant and slow forward flow, sharp changes in presence occur at the two ends of the channel. The resulting flow field gives rise to a delicate balance of pressure along the channel that controls the flow direction and magnitude. It is argued that there is a limitation on the maximum reverse flow achievable.The occurrence of reverse flow in a channel when an obstruction is placed at the entry is already known. In this article an attempt is made to bring out the mechanism that governs this phenomenon. Flow visualization and pressure measurements are employed for this purpose. The obstruction at the front end of the channel is essential for triggering the reverse flow. For reverse, stagnant and slow forward flow, sharp changes in pressure occur at the two ends of the channel. The resulting flow field gives rise to a delicate balance of pressure along the channel that controls the flow direction and magnitude. It is argued that there is a limitation on the maximum reverse flow achievable.

A detailed experimental investigation of interaction of free convection and radiation in a single fin mounted on a heated horizontal base has been carried out. The study makes use of a differential interferometer for estimating the convective heat fluxes. A numerical method coupled with the experimentally measured convective fluxes is used to evaluate the radiative fluxes. Experiments were conducted to study the effect of fin height, surface emissivity and the base temperature level on convection and radiation. Based on the experiments correlations have been presented for both the total and radiative heat transfer rates from the fin flats. Comparisons are made between the experimental results and two-dimensional numerical computations based on finite volume method. ? 1997 Elsevier Science Ltd.

In recent times, high-speed, airbreathing propulsion research has been receiving considerable attention all over the world. This has come about primarily because of renewed interest in the development of reusable launch vehicles employing multimode propulsive systems. The scramjet, a critical subsystem of these composite engines, is still in the developmental stage. A crucial problem in this development is the realization of rapid mixing and heat release with minimum pressure losses inside the supersonic combustor. Recently, a new mixing technique for high-speed flows employing large-scale axial vortices was developed. This involved the use of a lobed supersonic primary nozzle referred to as the petal nozzle. The possibility of applying this novel mixing mechanism to piloted supersonic combustors was examined in this work. Results showed that rapid mixing took place between the hot primary (pilot) stream and the cold secondary airstream when the petal nozzle was used. Piloted secondary (supersonic) combustion of kerosene and acetylene was achieved with satisfactory efficiencies.