Tsallis statistics generalization of non-equilibrium work relations

We use third constraint formulation of Tsallis statistics and derive the $q$-statistics generalization of non-equilibrium work relations such as the Jarzynski equality and the Crooks fluctuation theorem which relate the free energy differences between two equilibrium states and the work distribution of the non-equilibrium processes.Comment: 5 page

Nonequilibrium entropy production for open quantum systems

We consider open quantum systems weakly coupled to a heat reservoir and driven by arbitrary time-dependent parameters. We derive exact microscopic expressions for the nonequilibrium entropy production and entropy production rate, valid arbitrarily far from equilibrium. By using the two-point energy measurement statistics for system and reservoir, we further obtain a quantum generalization of the integrated fluctuation theorem put forward by Seifert [PRL 95, 040602 (2005)].Comment: 4 pages, 1 figur

Towards agent-based crowd simulation in airports using games technology

We adapt popular video games technology for an agent-based crowd simulation in an airport terminal. To achieve this, we investigate the unique traits of airports and implement a virtual crowd by exploiting a scalable layered intelligence technique in combination with physics middleware and a socialforces approach. Our experiments show that the framework runs at interactive frame-rate and evaluate the scalability with increasing number of agents demonstrating navigation behaviour

Vibrational Excitons in CH-Stretching Fundamental and Overtone Vibrational Circular Dichroism Spectra

A set of vibrational circular dichroism (VCD) spectra in the CH-stretching fundamental region for about twenty compounds belonging to the class of essential oils was empirically analyzed by the use of a sort of vibrational exciton mechanism, involving three centers. Through a general formula applicable to many coupled dipole oscillators, the rotational strengths of the previously identified vibrational excitons are evaluated. The results are then critically reviewed by the use of recent ab initio methodology, as applied to selected molecules of the original set. Further insight is gained by model calculations adding up the contribution of the coupling between electric dipole moments associated with normal mode behavior and that of the polarizability from polarizable groups. The former part is responsible for the excitonic behavior of the VCD spectra. For the same selected molecules we have also investigated whether some excitonic behavior is taking place in the second overtone region, and have concluded that this is not the case

Application of the "Full Cavitation Model" to the fundamental study of cavitation in liquid metal processing

Ultrasonic cavitation treatment of melt significantly improves the downstream properties and quality of conventional and advanced metallic materials. However, the transfer of this technology has been hindered by difficulties in treating large volumes of liquid metal. To improve the understanding of cavitation processing efficiency, the Full Cavitation Model, which is derived from a reduced form of the Rayleigh-Plesset equation, is modified and applied to the two-phase problem of bubble propagation in liquid melt. Numerical simulations of the sound propagation are performed in the microsecond time scale to predict the maximum and minimum acoustic pressure amplitude fields in the domain. This field is applied to the source term of the bubble transport equation to predict the generation and destruction of cavitation bubbles in a time scale relevant to the fluid flow. The use of baffles to limit flow speed in a launder conduit is studied numerically, to determine the optimum configuration that maximizes the residence time of the liquid in high cavitation activity regions. With this configuration, it is then possible to convert the batch processing of liquid metal into a continuous process. The numerical simulations will be validated against water and aluminium alloy experiments, carried out at Brunel University

Lombalgie chronique, COTOREP et reclassement professionnel en Moselle

Objectifs : Décrire les caractéristiques, la prise en charge, les résultats et le coût d\u27un reclassement professionnel concernant les assurés mosellans lombalgiques chroniques bénéficiant d’un accord de la Commission technique d\u27orientation et de reclassement professionnel (COTOREP). Méthodes : Etude descriptive menée entre août 2000 et mars 2001 dans le cadre d\u27un partenariat avec la COTOREP de Moselle intégrant 48 lombalgiques chroniques pour lesquels la COTOREP a donné en 1995 un accord de pré-orientation ou de reclassement professionnels. Résultats : Le lombalgique pris en charge était un homme jeune, de faible niveau scolaire et professionnel, en rupture avec le milieu du travail et souffrant d\u27une pathologie lombaire invalidante. Sur 32 formations suivies, 24 candidats ont réussi leur examen mais seuls dix diplômés ont trouvé un emploi. Huit diplômés ont trouvé un emploi conforme à la formation apprise. Le taux de reprise du travail était semblable pour les diplômés (10/24) et pour les autres lombalgiques (11/24). Le coût global pour l\u27assurance maladie variait de 25 000 en externat à 39 000 en internat. Conclusion : Devant la faible valeur ajoutée du reclassement professionnel que nous avons constatée, il paraît souhaitable de maintenir le lombalgique chronique dans son emploi en restaurant son rachis, en aménageant son poste de travail et, surtout, en gérant ses peurs et croyances liées au couple lombalgietravail

Molecular dynamics simulation of aqueous solutions of 26-unit segments of p(NIPAAm) and of p(NIPAAm) "doped" with amino acid based comonomers

We have performed 75-ns molecular dynamics (MD) simulations of aqueous solutions of a 26-unit NIPAAm oligomer at two temperatures, 302 and 315 K, below and above the experimentally determined lower critical solution temperature (LCST) of p(NIPAAm). We have been able to show that at 315 K the oligomer assumes a compact form, while it keeps a more extended form at 302 K. A similar behavior has been demonstrated for a similar NIPAAm oligomer, where two units had been substituted by methacryloyl-l-valine (MAVA) comonomers, one of them being charged and one neutral. For another analogous oligomer, where the same units had been substituted by methacryloyl-l-leucine (MALEU) comonomers, no transition from the extended to the more compact conformation has been found within the same simulation time. Statistical analysis of the trajectories indicates that this transition is related to the dynamics of the oligomer backbone, and to the formation of intramolecular hydrogen bonds and water-bridges between distant units of the solute. In the MAVA case, we have also evidenced an important role of the neutral MAVA comonomer in stabilizing the compact coiled structure. In the MALEU case, the corresponding comonomer is not equally efficacious and, possibly, is even hindering the readjustment of the oligomer backbone. Finally the self-diffusion coefficient of water molecules surrounding the oligomers at the two temperatures for selected relevant times is observed to characteristically depend on the distance from the solute molecules

Universal Static and Dynamic Properties of the Structural Transition in Pb(Zn1/3Nb2/3)O3

The relaxors Pb(Zn$_{1/3}$Nb$_{2/3}$)O$_{3}$ (PZN) and Pb(Mg$_{1/3}$Nb$_{2/3}$)O$_{3}$ (PMN) have very similar properties based on the dielectric response around the critical temperature $T_{c}$ (defined by the structural transition under the application of an electric field). It has been widely believed that these materials are quite different below $T_{c}$ with the unit cell of PMN remaining cubic while in PZN the low temperature unit cell is rhombohedral in shape. However, this has been clarified by recent high-energy x-ray studies which have shown that PZN is rhombohedral only in the skin while the shape of the unit cell in the bulk is nearly cubic. In this study we have performed both neutron elastic and inelastic scattering to show that the temperature dependence of both the diffuse and phonon scattering in PZN and PMN is very similar. Both compounds show a nearly identical recovery of the soft optic mode and a broadening of the acoustic mode below $T_{c}$. The diffuse scattering in PZN is suggestive of an onset at the high temperature Burns temperature similar to that in PMN. In contrast to PMN, we observe a broadening of the Bragg peaks in both the longitudinal and transverse directions below $T_{c}$. We reconcile this additional broadening, not observed in PMN, in terms of structural inhomogeneity in PZN. Based on the strong similarities between PMN and PZN, we suggest that both materials belong to the same universality class and discuss the relaxor transition in terms of the three-dimensional Heisenberg model with cubic anisotropy in a random field.Comment: 11 pages, 10 figures. Updated version after helpful referee comment

A comparative study of overtone CH- stretching vibrational circular dichroism spectra of fenchone and camphor

Near-infrared vibrational circular dichroism (VCD) spectra in the region 1500-850 nm are recorded for both enantiomers of camphor and fenchone using a home-built dispersive instrument. Two CH-stretching overtone regions and two CH-stretching/HCH-bending combination regions are investigated. The near-infrared VCD data are examined and compared with the corresponding previously published data of (3R)-(+)-methylcyclopentanone and (3R)-(+)-methylcyclohexanone. The absorption spectra of both the fundamental and overtone regions are also considered, and the fundamental CH-stretching VCD data are taken into account, where possible. An empirical assignment of the spectra is first considered, with special regard to the second CHstretching overtone region. This region is then investigated by a heuristic approach based on DFT calculations, using the hybrid functional B3LYP at the 6-31G** basis set level. Subsequently rotational strengths have been evaluated by use of a classical model based on the contribution of polarizable groups to the optical activity. The same models are also used to interpret the VCD spectra between 2000 and 3000 wavenumbers for (3R)-(+)-methylcyclopentanone-d4

Chiral Polyalkylthiophenes for Organic Light Emitting Diodes

Chiral polyalkylthiophenes are noncentrosymmetric organic materials which can be used both in second harmonic-generation devices and in polarized light emitting diodes. In this work we present the synthesis and the characterization of a polyalkylthiophene with a chiral center very close to the conjugated backbone: poly(3-[(S)-2-methylbutyl]thiophene) (PMBT). Circular dichroism (CD) measurements have been carried out to ascertain the chirality of these materials. The CD spectra show intense signals both in mixed solvents and in the solid state. The strong Cotton effect can be associated to a highly ordered aggregated phase whose nature is still under investigation. We also present the photo and electroluminescence characterization of single layer light emitting diode (LED) with the following configuration: ITO (Tin Indium Oxide)/PMBT/Al