Heat transfer in a swirling fluidized bed with Geldart type-D particles

A relatively new variant in fluidized bed technology, designated as the swirling fluidized bed (SFB), was investigated for its heat transfer characteristics when operating with Geldart type D particles. Unlike conventional fluidized beds, the SFB imparts secondary swirling motion to the bed to enhance lateral mixing. Despite its excellent hydrodynamics, its heat transfer characteristics have not been reported in the published literature. Hence, two different sizes of spherical PVC particles (2.61mm and 3.65mm) with the presence of a center body in the bed have been studied at different velocities of the fluidizing gas. The wall-to-bed heat transfer coefficients were measured by affixing a thin constant foil heater on the bed wall. Thermocouples located at different heights on the foil show a decrease in the wall heat transfer coefficient with bed height. It was seen that only a discrete particle model which accounts for the conduction between the particle and the heat transfer surface and the gas-convective augmentation can adequately represent the mechanism of heat transfer in the swirling fluidized bed

L'Estuaire, vol. 21 (2)

Éditorial -- Le naufrage de l'Empress of Ireland -- Addenda: Quand le mauvais sort s'acharne... sur l'Empress of Ireland -- Les premiers phares du Saint-Laurent -- Les Menier et Anticosti (1895-1926) -- Les 66 ans du Progrès du Golfe. C'était l'époque classique du journalisme à Rimouski -- Chroniques rimouskoises : L'émigration britannique de 1847 et de 1848 -- Lac-au-Saumon -- Le voyage de l'abbé Ferland en Gaspésie en 1836 -- Vieux écrits: Chanson gaspésienne -- Nouvelles brèves -- Des livres à lire

GABAergic modulation of olfactomotor transmission in lampreys.

Odor-guided behaviors, including homing, predator avoidance, or food and mate searching, are ubiquitous in animals. It is only recently that the neural substrate underlying olfactomotor behaviors in vertebrates was uncovered in lampreys. It consists of a neural pathway extending from the medial part of the olfactory bulb (medOB) to locomotor control centers in the brainstem via a single relay in the caudal diencephalon. This hardwired olfactomotor pathway is present throughout life and may be responsible for the olfactory-induced motor behaviors seen at all life stages. We investigated modulatory mechanisms acting on this pathway by conducting anatomical (tract tracing and immunohistochemistry) and physiological (intracellular recordings and calcium imaging) experiments on lamprey brain preparations. We show that the GABAergic circuitry of the olfactory bulb (OB) acts as a gatekeeper of this hardwired sensorimotor pathway. We also demonstrate the presence of a novel olfactomotor pathway that originates in the non-medOB and consists of a projection to the lateral pallium (LPal) that, in turn, projects to the caudal diencephalon and to the mesencephalic locomotor region (MLR). Our results indicate that olfactory inputs can induce behavioral responses by activating brain locomotor centers via two distinct pathways that are strongly modulated by GABA in the OB. The existence of segregated olfactory subsystems in lampreys suggests that the organization of the olfactory system in functional clusters may be a common ancestral trait of vertebrates

La Démocratie à l’épreuve de la gouvernance

Pour le profane, la gouvernance fait d'abord penser au fonctionnement des organisations, ou des institutions, et à la distribution du pouvoir dans ces structures. Le jargon dans ce domaine nous vient des spécialistes de la gestion des organisations, des sciences administratives et de la sociologie urbaine. Toutefois, en devenant de plus en plus un domaine privilégiant tant les analyses du politique que de la société, le thème de la gouvernance se révèle porteur d'une nouvelle ambition : celle de se présenter comme une solution de rechange à l'organisation du pouvoir. Le projet d'une nouvelle gouvernance distribuée se présente dorénavant comme une réponse aux transformations en cours du politique dans les sociétés démocratiques. La démocratie à l'épreuve de la gouvernance propose une réflexion dynamique et innovatrice sur l'idée de la gouvernance. Regroupés autour d'un texte central de Gilles Paquet, treize chercheurs émérites apportent des perspectives variées et stimulantes qui invitent le lecteur à mener une réflexion riche et nuancée