Design of amphoteric mixed oxides of zinc and Group 3 elements (Al, Ga, In): migration effects on basic features

EAU:ENERGIE+AMB:DGR:SBE:AAUThe design of new amphoteric catalysts is of great interest for several industrial processes, especially those covering dehydration and dehydrogenation phenomena. Adsorption microcalorimetry was used to monitor the design of mixed oxides of zinc with Group 3 elements (aluminium, gallium, indium) with amphoteric character and enhanced specific surface area. Acid-base features were found to evolve non-linearly with the relative amounts of metal, and the strengths of the created acidic or basic sites were measured by adsorption microcalorimetry. A panel of bifunctional catalysts of various acid-base (amounts, strengths) and redox character was obtained. Besides, special interest was given to In-Zn mixed oxides for their enhanced basicity: this series of catalysts displays important basic features of high strength (q(diff) (SO2 ads.) > 200 kJ mol(SO2)(-1)) in substantial amounts (1 - 2 mu mol m(catalyst)(-2)), whose impact on efficiency or selectivity in catalytic dehydration/dehydrogenation can be valuable

Lamb-type waves generated by a cylindrical bubble oscillating between two planar elastic walls

International audienceThe volume oscillation of a cylindrical bubble in a microfluidic channel with planar elastic walls is studied. Analytical solutions are found for the bulk scattered wave propagating in the fluid gap and the surface waves of Lamb-type propagating at the fluid-solid interfaces. This type of surface wave has not yet been described theoretically. A dispersion equation for the Lamb-type waves is derived, which allows one to evaluate the wave speed for different values of the channel height h. It is shown that for h < λ t , where λ t is the wavelength of the transverse wave in the walls, the speed of the Lamb-type waves decreases with decreasing h, while for h on the order of or greater than λ t , their speed tends to the Scholte wave speed. The solutions for the wave fields in the elastic walls and in the fluid are derived using the Hankel transforms. Numerical simulations are carried out to study the effect of the surface waves on the dynamics of a bubble confined between two elastic walls. It is shown that its resonance frequency can be up to 50% higher than the resonance frequency of a similar bubble confined between two rigid walls

Experimental Solid-Liquid Phase Equilibria of a Methyl Ester/Amide/Nitrile Ternary System by DSC

EAU:ENERGIE+AMB:SBE:AAUBinary and ternary mixtures of lauric methyl ester, amide and nitrile were investigated by differential scanning calorimetry, in order to determine the solid-liquid phase equilibria of this model for saturated organic systems. Eutectic mixtures were observed and followed in the ternary system, while solid-solid transitions and immiscibility phenomena were also characterized. This system is also of industrial interest for processes in the frame of biomass valorization

Are there Local Differences in Support for Violent Radicalization? A Study on College Students in the Province of Quebec, Canada

Support for violent radicalization (VR) is a multidimensional phenomenon determined by individual, social, and contextual variables. However, how local contexts influence the configurations of risk and protective factors leading to the process of VR remains an open question. In line with a socioecological framework, this study aims to investigate local differences in support for VR and its associated risk factors (i.e., immigrant status, social adversity, depression, and collective identity) among college students in Quebec, a Canadian province with a variety of social and political contexts (i.e., Francophone Montreal, Quebec City, rural/suburban areas, and Anglophone communities). A total of 1765 college students (71% women; 73% aged between 16 and 21 years) completed an online survey. Mixed-effects models were implemented to test local differences in support for VR and its risk factors. Results showed that the association between social adversity (i.e., discrimination and exposure to violence) and support for VR varied by local context. Specifically, social adversity was a risk factor across all contexts but Quebec City. Although prevention programs may target common determinants of support for VR, they need to be tailored according to local realities, and in particular the level of social diversity and the relative prevalence of mainstream radical discourses

Catalytic conversion of fatty acids into nitriles in liquid and gas phase : bifunctional catalysts evaluated by microcalorimétry

International @ ENERGIE+AMB:SBE:AAUInternational audienceNon

Zinc catalyzed conversion of fatty acids into nitriles at low temperature for aviation fuels

International @ ENERGIE+AMB:SBE:AAUInternational audienceNon