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Linear stability analysis of an electrified viscoelastic liquid jet / Li-jun Yang in Transactions of the ASME . Journal of fluids engineering, Vol. 134 N° 7 (Juillet 2012) 

Public ISBD [article]  in Transactions of the ASME . Journal of fluids engineering > Vol. 134 N° 7 (Juillet 2012) . - 13 p. Titre : Linear stability analysis of an electrified viscoelastic liquid jet Type de document : texte imprimé Auteurs : Li-jun Yang, Auteur ; Xin-Yu Liu, Auteur ; Qing-fei Fu, Auteur Année de publication : 2012 Article en page(s) : 13 p. Note générale : fluids engineering Langues : Anglais (eng) Mots-clés : linear  analysis;  electrified  jet;  viscoelastic  liquid Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : A linear instability analysis method has been used to investigate the breakup of an electrified viscoelastic liquid jet. The liquid is assumed to be a dilute polymer solution modeled by the linear viscoelastic constitutive equation. As for its electric properties, the liquid is assumed to be of perfect electrical conductivity. The axisymmetric and nonaxisymmetric disturbance wave growth rate has been worked out by solving the dispersion equation of an electrified viscoelastic liquid jet, which was obtained by combining the linear instability model of an electrified Newtonian liquid jet with the linear viscoelastic model. The maximum growth rate and corresponding dominant wavenumbers have been observed. The electrical Euler number, non-Newtonian rheological parameters and some flow parameters have been tested for their influence on the instability of the electrified viscoelastic liquid jet. The results show that the disturbance growth rate of electrified viscoelastic liquid jets is higher than that of Newtonian ones for axisymmetric mode disturbance and almost the same for the nonaxisymmetric mode. The growth rate of the axisymmetric mode is greater than that of the nonaxisymmetric mode for large wavenumbers, and the trend is opposite in the small wavenumber range. The ratio of gas to liquid density, electrical Euler number, and elasticity number can accelerate the breakup of the electrified viscoelastic liquid jet for both modes. The increase of the time constant ratio, zero shear viscosity, and jet radius can decrease the growth rate of the axisymmetric mode; however, their effects on the nonaxisymmetric mode are different. As for the effect of surface tension and jet velocity, there is a critical value. The variation trend is opposite when the surface tension or jet velocity is larger or smaller than the critical value. DEWEY : 620.1 ISSN : 0098-2202 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JFEGA4000134000007 [...] [article] Linear stability analysis of an electrified viscoelastic liquid jet [texte imprimé] / Li-jun Yang, Auteur ; Xin-Yu Liu, Auteur ; Qing-fei Fu, Auteur . - 2012 . - 13 p. fluids engineering Langues : Anglais (eng) in Transactions of the ASME . Journal of fluids engineering > Vol. 134 N° 7 (Juillet 2012) . - 13 p. Mots-clés : linear  analysis;  electrified  jet;  viscoelastic  liquid Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : A linear instability analysis method has been used to investigate the breakup of an electrified viscoelastic liquid jet. The liquid is assumed to be a dilute polymer solution modeled by the linear viscoelastic constitutive equation. As for its electric properties, the liquid is assumed to be of perfect electrical conductivity. The axisymmetric and nonaxisymmetric disturbance wave growth rate has been worked out by solving the dispersion equation of an electrified viscoelastic liquid jet, which was obtained by combining the linear instability model of an electrified Newtonian liquid jet with the linear viscoelastic model. The maximum growth rate and corresponding dominant wavenumbers have been observed. The electrical Euler number, non-Newtonian rheological parameters and some flow parameters have been tested for their influence on the instability of the electrified viscoelastic liquid jet. The results show that the disturbance growth rate of electrified viscoelastic liquid jets is higher than that of Newtonian ones for axisymmetric mode disturbance and almost the same for the nonaxisymmetric mode. The growth rate of the axisymmetric mode is greater than that of the nonaxisymmetric mode for large wavenumbers, and the trend is opposite in the small wavenumber range. The ratio of gas to liquid density, electrical Euler number, and elasticity number can accelerate the breakup of the electrified viscoelastic liquid jet for both modes. The increase of the time constant ratio, zero shear viscosity, and jet radius can decrease the growth rate of the axisymmetric mode; however, their effects on the nonaxisymmetric mode are different. As for the effect of surface tension and jet velocity, there is a critical value. The variation trend is opposite when the surface tension or jet velocity is larger or smaller than the critical value. DEWEY : 620.1 ISSN : 0098-2202 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JFEGA4000134000007 [...]

Visible–light–induced photodegradation of rhodamine B over hierarchical TiO2 / Lun Pan in Industrial & engineering chemistry research, Vol. 51 N° 39 (Octobre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12782-12786 Titre : Visible–light–induced photodegradation of rhodamine B over hierarchical TiO2 : Effects of storage period and water-mediated adsorption switch Type de document : texte imprimé Auteurs : Lun Pan, Auteur ; Ji-Jun Zou, Auteur ; Xin-Yu Liu, Auteur Année de publication : 2012 Article en page(s) : pp. 12782-12786 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Adsorption  Storage  Titanium  oxide  Photochemical  degradation  Visible  radiation Résumé : Hierarchical TiO2 was prepared via hydrolysis method and characterized by XRD, N2 adsorption―desorption, UV―vis diffusion, and NH3―TPD. With the increase of calcination temperature, the surface area and surface hydroxyls of UV―vis diffusion, and NH3―TPD. With the increase of calcination temperature, the surface area and surface hydroxyls of prepared materials decrease rapidly. The photoactivity was evaluated using the self-sensitized photodegradation of rhodamine B under visible light The fresh samples show higher activity than P-25 due to higher surface area and more effective light utilization. After stored in air for ca. half a year, the materials show significantly increased photoactivity, due to the prebonding of water on surface bridging hydroxyls, which induces water-mediated adsorption switch from covalent mode to electrostatic one. Water treatment further promotes the photoactivity of stored samples, because more water are bonded on TiO2 surface. It is found that the water-mediated effect closely depends on the surface area and amount of surface bridging hydroxyls. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419233 [article] Visible–light–induced photodegradation of rhodamine B over hierarchical TiO2 : Effects of storage period and water-mediated adsorption switch [texte imprimé] / Lun Pan, Auteur ; Ji-Jun Zou, Auteur ; Xin-Yu Liu, Auteur . - 2012 . - pp. 12782-12786. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12782-12786 Mots-clés : Adsorption  Storage  Titanium  oxide  Photochemical  degradation  Visible  radiation Résumé : Hierarchical TiO2 was prepared via hydrolysis method and characterized by XRD, N2 adsorption―desorption, UV―vis diffusion, and NH3―TPD. With the increase of calcination temperature, the surface area and surface hydroxyls of UV―vis diffusion, and NH3―TPD. With the increase of calcination temperature, the surface area and surface hydroxyls of prepared materials decrease rapidly. The photoactivity was evaluated using the self-sensitized photodegradation of rhodamine B under visible light The fresh samples show higher activity than P-25 due to higher surface area and more effective light utilization. After stored in air for ca. half a year, the materials show significantly increased photoactivity, due to the prebonding of water on surface bridging hydroxyls, which induces water-mediated adsorption switch from covalent mode to electrostatic one. Water treatment further promotes the photoactivity of stored samples, because more water are bonded on TiO2 surface. It is found that the water-mediated effect closely depends on the surface area and amount of surface bridging hydroxyls. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419233