50 research outputs found

    THE EMOTIONAL POWER OF ODORS: IDENTIFYING THE DIMENSIONS REFERRING TO FEELINGS PRODUCED BY ODORS

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    Abstract There is broad literature on the emotional effect of odors but, so far, little concern with the precise mechanism underlying the elicitation of emotions via olfactory stimuli. One reason for this neglect might be the lack of answers to a major question that underlie any research on odors and emotions: What exactly are the emotions associated to odors and how are they organised? The major issue addressed in the present paper concerns the nature of the verbal labels that refer to the specific states produced by odors. We conducted a series of studies in order to examine which terms are best suited to describe the feelings associated to odors and autobiographical memories. In Study 1, the relevance of a broad list of candidate affect terms to describe odor-related feelings was examined by two groups of participants with different level of knowledge about odors. In study 2, the most relevant terms retained from study 1 were evaluated with actual odorant samples and the data were submitted to a series of exploratory factor analyses to reduce the set of variables to a smaller set of summary-scales and to get a preliminary sense of the differentiation of affects elicited by odors. The Study 3 replicated Study 2 with a larger and more representative sample of odorant samples and participants. Overall, the findings point to a structure of affective responses to odors that differs from the more traditional taxonomies of emotion such as posited by discrete emotion or dimensional theories and suggest that affective states elicited by odors are structured around few dimensions that clearly reflect the role of olfaction in social interactions, danger prevention and arousal/relaxation sensations

    Raman spectra and reentrant phase diagram of malononitrile CH2(CN) 2

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    Raman spectra of malononitrile are investigated under pressure up to 8 kbar at temperatures extending from 77 K to 320 K. The low pressure part of the phase diagram, containing a second order reentrant phase transition is completed and it is shown that the origin of the reentrant character can be interpreted on the basis of a strong anharmonic coupling with an elastic deformation of Ag symmetry. A new first order phase transition, also reentrant, is discovered in the higher pressure part of the phase diagram.Les spectres Raman du malononitrile sous des pressions pouvant s'élever jusqu'à 8 kbar et à des températures allant de 77 K à 320 K ont été mesurés. Ils permettent de compléter le domaine des basses pressions du diagramme de phase qui contient une transition de phase réentrante dont on montre que le caractère réentrant provient d'un fort couplage anharmonique avec une déformation élastique de symétrie A g. Dans le domaine des pressions plus élevées du diagramme de phases, on a découvert une nouvelle transition de phase, du premier ordre et également réentrante

    On phase transitions in NH4HSeO4\mathsf{{\rm NH}_{4}{\rm HSeO}_{4}} and ND4_{4}DSeO4_{4}

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    We propose a hypothetical prototype phase (space group Imm) from which all observed phases in NH4_{4}HSeO4_{4} and ND4_{4}DSeO4_{4} can be deduced by introducing order parameters of definite symmetries. Following this hypothesis the symmetry of the superionic phase should be P2/n in disagreement with recent experimental results. Free energies of Landau type are derived by means of which particular phase transitions could be described. The large dielectric anomaly near 252 K in NH4_{4}HSeO4_{4} is discussed in some detail. The first order phase transition in ND4_{4}DSeO4_{4} from the room temperature phase P212121_{1}2_{1}2_{1} into commensurate lock-in phase (with the wave-vector k z(0,0,π/c)_{z}(0,0, \pi/{c})) has been investigated by neutron elastic scattering and the symmetry of the latter has been found to be P1121_{1} in agreement with our theoretical prediction.Nous proposons une phase prototype hypothétique (de groupe d'espace Immm) à partir de laquelle on peut déduire toutes les phases observées dans NH4_{4}HSeO4_{4} et ND4_{4}DSeO4_{4} par l'introduction de paramètres d'ordre ayant une symétrie définie. D'après cette hypothèse le groupe d'espace de la phase superionique doit être P2/n ce qui est en désaccord avec des résultats expérimentaux récents. Pour chaque transition de phase on écrit l'énergie libre de type Landau à partir de laquelle elle peut être décrite. La grande anomalie diélectrique au voisinage de 252 K dans le composé NH4_{4}HSeO4_{4} est discutée de façon détaillée. Dans le composé ND4_{4}DSeO4_{4}, nous avons étudié par diffusion élastique de neutrons la transition de phase du premier ordre qui transforme le cristal de la structure P212121_{1}2_{1}2_{1} dans la phase commensurable d'accrochage (de vecteur d'onde k z(0,0,π/c)_{z}(0,0, {\pi}/{c})). Nous avons montré que la symétrie de cette phase est P1121_{1}, ce qui en accord avec nos prévisions théoriques

    Structural Study of TlH2_2PO4_4 and TlD2_2PO4_4 in the High Temperature Phase

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    The crystal structures of both TlH2_2PO4_4 and its deuterated form TlD2_2PO4_4 have been studied at 373 K using single-crystal neutron diffraction. Data were collected on a four-circle diffractometer at λ=0.830\lambda=0.830 Å. At this temperature both compounds have the same orthorhombic structure, space group Pbcn, which is the parent phase of the two different sequences of phase transitions observed in TDP and DTDP on decreasing temperature.Les structures cristallines de TlH2_2PO4_4 et TlD2_2PO4_4 ont été déterminées à 373 K par diffraction de neutrons sur des échantillons monocristallins. L'acquisition de données est faite avec un diffractomètre 4-cercles, en utilisant la longueur d'onde λ=0.830\lambda=0.830 Å. A cette température les deux composés ont la même symétrie orthorhombique décrite dans le groupe d'espace Pbcn. Cette phase haute température apparaît comme la phase “mère" du diagramme de phase obtenu pour des températures décroissantes pour chacun des deux composés TDP et DTDP
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