Documents disponibles écrits par cet auteur

Corrosion protection of stainless steel by separate polypyrrole electrode in acid solutions / J. Hu in Materials and corrosion, Vol. 62 N° 1 (Janvier 2011) 

Public ISBD [article]  in Materials and corrosion > Vol. 62 N° 1 (Janvier 2011) . - pp. 68–73 Titre : Corrosion protection of stainless steel by separate polypyrrole electrode in acid solutions Type de document : texte imprimé Auteurs : J. Hu, Auteur ; H. Zhu, Auteur ; Y. Ma, Auteur Année de publication : 2011 Article en page(s) : pp. 68–73 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : 410-stainless  steel  Acid  solution  corrosion  Galvanic  anodic  protection  Polypyrrole Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Galvanic anodic protection (GAP) of stainless steels by doped polypyrrole (PPy) was investigated using chemically synthesized PPy. Separate PPy powder-pressed electrodes with different surface areas were prepared. Electrochemical properties of PPy electrodes were studied by open circuit potentials (OCPs) and potentiostatic polarization. PPy powder-pressed electrodes were coupled with 410-stainless steel electrodes in different concentrations of sulfuric acid solutions, 5 M phosphoric acid solution, and industrial phosphoric acid solution (5 M phosphoric acid + 0.05% chloride ion). Remarkable shift of OCP to the positive direction and sharp decrease of corrosion rate were observed during the coupling experiments, which implies that 410-stainless steel was transferred to passive state. Results also showed that PPy electrode with sufficient surface area can provide corrosion protection to 410-stainless steel electrode in highly corrosive acid solution. Based on the experiment results, GAP provided by PPy and PANi (synthesized under similar conditions) was compared. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905344/abstract [article] Corrosion protection of stainless steel by separate polypyrrole electrode in acid solutions [texte imprimé] / J. Hu, Auteur ; H. Zhu, Auteur ; Y. Ma, Auteur . - 2011 . - pp. 68–73. Génie Mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 62 N° 1 (Janvier 2011) . - pp. 68–73 Mots-clés : 410-stainless  steel  Acid  solution  corrosion  Galvanic  anodic  protection  Polypyrrole Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Galvanic anodic protection (GAP) of stainless steels by doped polypyrrole (PPy) was investigated using chemically synthesized PPy. Separate PPy powder-pressed electrodes with different surface areas were prepared. Electrochemical properties of PPy electrodes were studied by open circuit potentials (OCPs) and potentiostatic polarization. PPy powder-pressed electrodes were coupled with 410-stainless steel electrodes in different concentrations of sulfuric acid solutions, 5 M phosphoric acid solution, and industrial phosphoric acid solution (5 M phosphoric acid + 0.05% chloride ion). Remarkable shift of OCP to the positive direction and sharp decrease of corrosion rate were observed during the coupling experiments, which implies that 410-stainless steel was transferred to passive state. Results also showed that PPy electrode with sufficient surface area can provide corrosion protection to 410-stainless steel electrode in highly corrosive acid solution. Based on the experiment results, GAP provided by PPy and PANi (synthesized under similar conditions) was compared. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905344/abstract

Plane-strain propagation of a fluid-driven crack in a permeable rock with fracture toughness / J. Hu in Journal of engineering mechanics, Vol. 136 N° 9 (Septembre 2010) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 136 N° 9 (Septembre 2010) . - pp. 1152-1166 Titre : Plane-strain propagation of a fluid-driven crack in a permeable rock with fracture toughness Type de document : texte imprimé Auteurs : J. Hu, Auteur ; D. I. Garagash, Auteur Article en page(s) : pp. 1152-1166 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Cracking  Porous  media  Leakage  Numerical  analysis  Rocks. Résumé : A solution to the problem of a plane-strain fluid-driven crack propagation in elastic permeable rock with resistance to fracture is presented. The fracture is driven by injection of an incompressible Newtonian fluid at a constant rate. The solution, restricted to the case of zero lag between the fluid front and the fracture tip, evolves from the early-time regime when the fluid flow takes place mostly inside the crack toward the large-time response when most of the injected fluid is leaking from the crack into the surrounding rock. This transition further depends on a time-invariant partitioning between the energy expanded to overcome the rock fracture toughness and the energy dissipated in the viscous fluid flow in the fracture. A numerical approach is used to compute the solution for the normalized crack length and crack opening and net-fluid pressure profiles as a function of two dimensionless parameters: the leak-off/storage evolution parameter and the toughness/viscosity number. Relation of this solution to the various available asymptotic solutions is discussed. Obtained mapping of the solution onto the problem parametric space has a potential to simplify the tasks of design, modeling, and data inversion for hydraulic fracturing treatments and laboratory experiments. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JENMDT000 [...] [article] Plane-strain propagation of a fluid-driven crack in a permeable rock with fracture toughness [texte imprimé] / J. Hu, Auteur ; D. I. Garagash, Auteur . - pp. 1152-1166. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 136 N° 9 (Septembre 2010) . - pp. 1152-1166 Mots-clés : Cracking  Porous  media  Leakage  Numerical  analysis  Rocks. Résumé : A solution to the problem of a plane-strain fluid-driven crack propagation in elastic permeable rock with resistance to fracture is presented. The fracture is driven by injection of an incompressible Newtonian fluid at a constant rate. The solution, restricted to the case of zero lag between the fluid front and the fracture tip, evolves from the early-time regime when the fluid flow takes place mostly inside the crack toward the large-time response when most of the injected fluid is leaking from the crack into the surrounding rock. This transition further depends on a time-invariant partitioning between the energy expanded to overcome the rock fracture toughness and the energy dissipated in the viscous fluid flow in the fracture. A numerical approach is used to compute the solution for the normalized crack length and crack opening and net-fluid pressure profiles as a function of two dimensionless parameters: the leak-off/storage evolution parameter and the toughness/viscosity number. Relation of this solution to the various available asymptotic solutions is discussed. Obtained mapping of the solution onto the problem parametric space has a potential to simplify the tasks of design, modeling, and data inversion for hydraulic fracturing treatments and laboratory experiments. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JENMDT000 [...]