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The molten globule (MG) state or the A-state of cytochrome c (cyt c) has been induced by addition of salts sodium perchlorate (NaClO4), sodium thiocyanate (NaSCN), and sodium sulphate (Na2SO4) at pH 2.0. Isothermal titration calorimetry (ITC) has been used for determining the energetics of binding of 8-anilino naphthalene sulphonate (ANS) to the salt induced A-state of cyt c, and the accompanying thermodynamic parameters have been analyzed to elucidate the nature of the interactions between ANS and the A-state of cyt c. Temperature dependent studies of the binding process reveal that the binding is not a two state process and there are more than a single type of interactions involved. Addition of a bulky salt tetraethylammonium bromide (TEAB) increases the stoichiometry of binding significantly, with a reduction in the binding affinity at a higher concentration. The results provide quantitative information on the binding of ANS to the salt induced molten globule states of cyt c. It is further inferred that the binding involves a combination of hydrophobic and electrostatic interactions., © Elsevier

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.

A new dinuclear silver(I)-saccharinato (sac) complex with acetonitrile (MeCN), [Ag-2(sac)(2)(MeCN)(2)](n) has been synthesized and characterized by elemental analysis, IR spectroscopy and single crystal X-ray diffraction. The silver(I) ions are doubly bridged by two sac ligands, leading to a short argentophilic contact of 2.9074(3) angstrom. Each silver(I) ion exhibits a square-planar coordination geometry including the Ag-Ag bonds. The individual dimeric molecules are extended into a two-dimensional layered structure by weak Ag center dot center dot center dot Csac(eta(2)) interactions of ca. 3.2 angstrom. These interactions were discussed and compared with those found in the first silver(I)-sac complex [Ag(sac)](n).

12-Phosphotungstic acid supported on porous hydrous zirconia was prepared and characterized by N2 adsorption isotherm, powder XRD, FTIR, 31P MAS NMR, H2-TPR, NH3-TPD, SEM and TEM. It is found that the chemical interaction of Keggin anions with hydrous zirconia is different compared to the interaction with ZrO2 and Ce0.5Zr0.5O2 supports. The phosphotungstic acid clusters dispersed on porous hydrous zirconia did not show any split of IR bands at 1080 cm-1 (?P-O) and 983 cm-1 (?W{double bond, long}O,ter) while those dispersed on ZrO2 and Ce0.5Zr0.5O2 showed a split in these two bands due to the lowering of symmetry of the central PO4 tetrahedron and direct interaction of W{double bond, long}Oter with oxide support. The dispersion of phosphotungstic acid on porous hydrous zirconia led to the growth of crystallites which showed catalytic activity for liquid-phase esterification of 2-ethyl-1-hexanol with acetic acid. Both conversion of 2-ethyl-1-hexanol and selectivity for 2-ethyl-1-hexyl acetate can be achieved at 100%. � 2008 Elsevier B.V. All rights reserved.

Myosin V motors regulate secretion and cell division in eukaryotes. How MyoV activity is differentially regulated by essential and calmodulin light chain binding remains unclear. We have used NMR spectroscopy to compare the dynamic behavior of Mlc1p, a budding yeast essential light chain, with that of the Xenopus laevis calmodulin. Both proteins have a similar structure and bind similar target proteins but differ in the mechanism by which they interact with the myosin V IQ1. This interaction is essential for MyoV activity. Here, we show that the rigid conformation of the loop connecting the two EF-hand motifs of the Mlc1p N-lobe explains its differential ability to interact with myosin V IQ1. Moreover, we show that the maintenance of the N-lobe structure is required for the essential function of Mlc1p in vivo. These data show that the core characteristics of myosin light chain N-lobes differentiate Mlc1p and calmodulin binding capability.

This paper presents domain form of the interaction integrals based on three independent formulations for computation of the stress intensity factors and electric displacement intensity factor for cracks in functionally graded piezoelectric materials. Conservation integrals of J-type are derived based on the governing equations for piezoelectric media and the crack tip asymptotic fields of homogeneous piezoelectric medium as auxiliary fields. Each of the formulation differs in the way auxiliary fields are imposed in the evaluation of interaction integral and each of them results in a consistent form of the interaction integral in the sense that extra terms naturally appears in their derivation to compensate for the difference in the chosen crack tip asymptotic fields of homogeneous and functionally graded piezoelectric medium. The additional terms play an important role of ensuring domain independence of the presented interaction integrals. Comparison of the numerically evaluated intensity factors through the three consistent formulations with those obtained using displacement extrapolation method is presented by means of two examples. � 2008 Elsevier Ltd. All rights reserved.

The two-dimensional time domain simulation of nonlinear waves has received considerable attention in the recent years, in which a mixed Eulerian and Lagrangian method (MEL) shows potential application. In this paper, the finite element method is used in the domain for the estimation of the velocity potential, while, a cubic spline approximation is used to recover the velocity. The present methodology has been compared with the laboratory simulation of a Cnoidal wave over a long time far away from the wave making boundary. The present numerical model is further extended to investigate the interactions with the submerged obstacles. This reveals that by using the present methodology, the dispersive characteristics are not predicted well, compared, to the experimental measurements for very steep waves. Further modification is carried out for the velocity recovery by using least square method to overcome the difficulties in the simulation of steep waves. Smoothing or regridding is not applied in the simulation unlike in most of the existing simulation. � 2007 International Association for Hydraulic Engineering and Research, Asia Pacific Division.

This paper explores some fundamental issues involved in flame-acoustic interaction in the context of non-premixed flames. The combustion model considered is a two-dimensional co-flowing non-premixed flame in a uniform flow field, as in the Burke-Schumann geometry. Both finite-rate and infinite-rate chemistry effects are examined. First, the velocity-coupled response of the flame to an externally imposed velocity fluctuation is studied at various frequencies of interest. The Damk�hler number plays an important role in determining the amplitude and phase of the heat release fluctuations with respect to the velocity fluctuations. Second, the combustion model is coupled with the duct acoustics. The one-dimensional acoustic field is simulated in the time domain using the Galerkin method, taking the fluctuating heat release from the combustion zone as a compact acoustic source. The combustion oscillations are shown to cause exchange of acoustic energy between the different natural modes of the duct over several cycles of the acoustic oscillations.

Flow visualization studies on the effect of a splitter plate (SP) in the wake of rectangular cylinders of aspect ratios 0.1 and 1.0 are presented; the aspect ratio being defined as the ratio of the depth (B) of the cylinder to the width (D) of the cylinder. The length of the splitter plate is kept as 1D. The SP is placed parallel to the centerline, both along and away from it. The gap between the rear of the cylinder and the leading edge of SP is denoted by G and the lateral position from the centerline is denoted by Z. It is observed that for a model with the B/D ratio of 0.1, the SP has no significant influence on the flow when placed beyond G/D of 2.5 at Z/D of 0.0 While for the square cylinder case, the SP has no appreciable effect for G/D > 1.25D along the centerline at Z/D = 0.0. The critical gap defined as the G/D for which undulations in the flow pattern behind the cylinder are minimized, is found to be 2.25D and 1D respectively for rectangular and square cylinders when the SP is placed along the centerline. Influence of Z/D on the critical gap is also examined. The critical gap is observed to be always lower for the square cylinder. Copyright ? 2005 Begell House, Inc.

[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.

Date of Conference: 10-17 August 2005 Conference Name: 24th International Conference on Low Temperature Physics, LT24 2005 Motivated by the pionieering experiments of Buks et al. [Nature 391, 871 (1998)] we investigate the visibility of the Fano effect in a single-dot Aharonov-Bohm interferometer which is Coulomb-coupled to a nearby quantum dot. The latter acts as a 'Which Path Detector' and is coupled to two leads on which a finite bias is applied. Using the non-equilibrium Keldysh-Green function formalism we compute the currents through the detector and the interferometer. We take into account the first two contributions to the interaction selfenergy and emphasize the correction to the Landauer formula which appears beyond the single-particle approximation. Particular attention is given to the coherence properties of the interferometer in the presence of the electron-electron interaction between the embedded dot and the detector. We show that when the detector is subjected to a finite bias the amplitude of Aharonov-Bohm oscillations of the current through the interferometer decreases. The Fano line is in turn rather stable under interaction. Our results generalize an earlier work of Silva and Levit [Phys. Rev. B 63, 201309 (2001)] and complement the existing description of the controlled dephasing.

Results from 3D, compressible, unsteady Favre-averaged calculations of transverse injection into a supersonic cross flow are reported. Four injector geometries, namely, circular, wedge, diamond, and chevron, have been investigated. The effectiveness of the chevron injector is demonstrated by comparing performance metrics, such as degree of mixing and total pressure loss, against those of the other injectors. The results show that the chevron injector provides better mixing and spreading compared to other injectors, with almost the same total pressure loss. Furthermore, for the operating conditions studied, the chevron-penetration angle is shown to have a minimal impact on the mixing and the total pressure loss.

The aerodynamics of a coolant jet in a hot crossflow in an environment representative of the gas turbine practice, is numerically investigated for film cooling applications. The time-dependent, mass-averaged Navier-Stokes equations coupled with the compressible form of a two-equation low-Reynolds number (k-e{open}) model are solved based on an explicit finite volume formulation. The computed flow-field and surface temperature distributions along with the turbulence quantities are presented to illustrate the variation of flow-physics and heat transfer phenomena which occur in a jet-crossflow interaction with changing blowing rates, slot angles, and inlet free-stream turbulence levels. ? 1995 Indian Academy of Sciences.

Particle-wall interactions determine in different ways the operating conditions of plasma sources, ion accelerators, and beams operating in vacuum. For instance, a contribution to gas heating is given by ion neutralization at walls; beam losses and stray particle production - detrimental for high current negative ion systems such as beam sources for fusion - are caused by collisional processes with residual gas, with the gas density profile that is determined by the scattering of neutral particles at the walls. This paper shows that Molecular Dynamics (MD) studies at the nano-scale can provide accommodation parameters for gas-wall interactions, such as the momentum accommodation coefficient and energy accommodation coefficient: in non-isothermal flows (such as the neutral gas in the accelerator, coming from the plasma source), these affect the gas density gradients and influence efficiency and losses in particular of negative ion accelerators. For ideal surfaces, the computation also provides the angular distribution of scattered particles. Classical MD method has been applied to the case of diatomic hydrogen molecules. Single collision events, against a frozen wall or a fully thermal lattice, have been simulated by using probe molecules. Different modelling approximations are compared.

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.

The necessity of understanding the detailed mechanism of flap dynamics in designing HIV-1 protease inhibitors is immense. Crystal structures have provided us with a static overview of various conformations of the enzyme, but the existence of strong interplay among various conformations came to the fore only after dynamics studies. Here we elucidate the mechanistic aspects of HIV-1 protease flap closing upon binding inhibitors using all-atom molecular dynamics simulations. The unrestrained simulations reproduced not only the correct inhibitor-bound protease closed structures but also the structural water molecule which is seen in all protease-ligand X-ray sttuctures. The study demonstrates that the structural water plays a critical role in flap closing dynamics by destabilizing the hydrophobic clusters and subsequently by mediating the flap-ligand interactions. Our results corroborate well with prior simulation and experimental findings and, at the same time, provide a molecular level description of the HIV-1 protease flap closing mechanism which can be crucial in the understanding of drug-receptor interactions. � 2008 American Chemical Society.

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

Nonlinearities in SOAs have been deeply investigated both theoretically and experimentally. Moreover, many simulative models have been proposed, so far. The most used simulative approach is based on Rate Equations, relating the carrier density to the overall optical power traveling the amplifier. Aim of this paper is to propose an enhanced general model for nonlinearities induced in SOAs employed in WDM systems, overcoming the limitations of Rate Equations based model. Our model relates the carrier density to the optical field, and it allows to evaluate the interchannel crosstalk due to nonlinear interaction between channels, as a function of the signal waveform. Besides the theoretical approach, preliminary experimental results confirm the accuracy of this model in describing the demonstrates the crosstalk due to nonlinear interaction.

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

In this paper, instability mechanisms in a low Mach number reacting flow are investigated. Here, the emphasis is on the growth or decay of acoustic oscillations which arise from the acoustic-hydrodynamic interaction in a low Mach number reacting flow. Motivated by the studies in magnetohydrodynamics and atmospheric flows, we propose to investigate the acoustic-hydrodynamic coupling as a system of wave-mean flow interaction. For example, a comparison with the heat fluctuation modified hydrodynamics associated with magnetohydrodynamics is useful in understanding this coupling. The wavelike acoustic disturbance is introduced here as a compressibility correction to the mean flow. Accounting for the multiple scales introduced by the weak compressibility, we derive a set of equations governing wave-mean flow interaction in a reacting low Mach number flow. Sources such as volume expansion (which, in atmospheric flows arises due to the density variation with altitude) occur in reacting flows due to the heat release rate. This heat release rate, when coupled with the acoustic field, often leads to self-sustained thermo-acoustic oscillations. In the study of such oscillations, we discover a relation between the acoustic pressure and second order thermal fluctuations. Further, using this relation, we discover the nonlinear coupling mechanism that would lead to self-sustained oscillations in a reacting low Mach number flow. This mechanism, represented by a coupled convection reaction diffusion system, is presented here for the first time. In addition to the acoustic pressure and temperature fields, we also discover the role of acoustic velocity field in the acoustic-hydrodynamic interaction through a convective and lift-up mechanism. � 2015 AIP Publishing LLC.

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.