Documents disponibles écrits par cet auteur

A fast implicit algorithm for time-dependent dynamic simulations of air bearing sliders / Wei Hua in Transactions of the ASME . Journal of tribology, Vol. 134 N° 3 (Juillet 2012) 

Public ISBD [article]  in Transactions of the ASME . Journal of tribology > Vol. 134 N° 3 (Juillet 2012) . - 08 p. Titre : A fast implicit algorithm for time-dependent dynamic simulations of air bearing sliders Type de document : texte imprimé Auteurs : Wei Hua, Auteur ; Shengkai Yu, Auteur ; Zhou Weidong, Auteur Année de publication : 2012 Article en page(s) : 08 p. Note générale : tribology Langues : Anglais (eng) Mots-clés : implicit  algorithm;  dynamic  simulation;  finite  volume  method;  air  bearing  slider;  hard  disk Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : An unstructured triangular mesh is successfully applied to the static simulations of air bearing sliders due to its flexibility, accuracy and mesh efficiency in capturing various complex rails and recess wall regions of air bearing surface, as well as fast simulation speed. This paper introduces a new implicit algorithm with second order time accuracy for the time-dependent simulations of the slider dynamics and available for the unstructured triangular mesh. The new algorithm is specially developed for the finite volume method. Since the algorithm has second order time accuracy, it provides the flexibility of applying various time steps while guaranteeing the numerical accuracy and convergence. Moreover, the unstructured triangular mesh is highly efficient and fewer nodes are used. Finally, due to the small variation of flying attitude between two neighboring time steps, it is especially efficient for iteration methods which are used in the finite volume method. As a result, the algorithm shows very fast speed in time-dependent dynamic simulations. Simulation studies are conducted on the flying dynamics of a thermal flying-height control slider after external excitations. The simulation results are compared with the simulation results obtained by the rectangular mesh based on the finite element method. It is observed that the simulation results are well correlated. The fast Fourier transform is also employed to analyze the air bearing frequencies. It is indicated that the new algorithm is of high efficiency and importance for time-dependent dynamic simulations. DEWEY : 621.5 ISSN : 0742-4787 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JOTRE9000134000003 [...] [article] A fast implicit algorithm for time-dependent dynamic simulations of air bearing sliders [texte imprimé] / Wei Hua, Auteur ; Shengkai Yu, Auteur ; Zhou Weidong, Auteur . - 2012 . - 08 p. tribology Langues : Anglais (eng) in Transactions of the ASME . Journal of tribology > Vol. 134 N° 3 (Juillet 2012) . - 08 p. Mots-clés : implicit  algorithm;  dynamic  simulation;  finite  volume  method;  air  bearing  slider;  hard  disk Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : An unstructured triangular mesh is successfully applied to the static simulations of air bearing sliders due to its flexibility, accuracy and mesh efficiency in capturing various complex rails and recess wall regions of air bearing surface, as well as fast simulation speed. This paper introduces a new implicit algorithm with second order time accuracy for the time-dependent simulations of the slider dynamics and available for the unstructured triangular mesh. The new algorithm is specially developed for the finite volume method. Since the algorithm has second order time accuracy, it provides the flexibility of applying various time steps while guaranteeing the numerical accuracy and convergence. Moreover, the unstructured triangular mesh is highly efficient and fewer nodes are used. Finally, due to the small variation of flying attitude between two neighboring time steps, it is especially efficient for iteration methods which are used in the finite volume method. As a result, the algorithm shows very fast speed in time-dependent dynamic simulations. Simulation studies are conducted on the flying dynamics of a thermal flying-height control slider after external excitations. The simulation results are compared with the simulation results obtained by the rectangular mesh based on the finite element method. It is observed that the simulation results are well correlated. The fast Fourier transform is also employed to analyze the air bearing frequencies. It is indicated that the new algorithm is of high efficiency and importance for time-dependent dynamic simulations. DEWEY : 621.5 ISSN : 0742-4787 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JOTRE9000134000003 [...]

Fouling and corrosion properties of SiO2 coatings on copper in geothermal water / Chen Ning in Industrial & engineering chemistry research, Vol. 51 N° 17 (Mai 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 17 (Mai 2012) . - pp. 6001–6017 Titre : Fouling and corrosion properties of SiO2 coatings on copper in geothermal water Type de document : texte imprimé Auteurs : Chen Ning, Auteur ; Liu Mingyan, Auteur ; Zhou Weidong, Auteur Année de publication : 2012 Article en page(s) : pp. 6001–6017 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Geothermal  utilization  Corrosion  Silica  coatings Résumé : Two critical problems in geothermal utilization are corrosion and fouling on the surfaces of plants and fittings, and use of surface coatings is a good method to overcome such difficulties. Silica coatings with film thickness of several hundred nanometers on copper substrates were prepared by the liquid-phase deposition technique and characterized with respect to surface morphology, composition, surface free energy, roughness, and film thickness. Examinations of both fouling in calcium carbonate solution and corrosion in corrosive geothermal water on the surfaces of SiO2-coated samples were performed. The results showed that the fouling rate on the SiO2-coated surface was obviously reduced compared with that on the polished surface. Moreover, the inhibition of corrosion on the modified surface was found even though, after a long immersion time, the corrosion resistance action decreased because of the surface peeling of SiO2-coated samples. The corrosion behavior of the SiO2 coating was further studied with electrochemical measurements by electrochemical impedance spectroscopy. This work suggests a new possibility for solving the fouling and corrosion issues encountered in the use of geothermal water. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202091b [article] Fouling and corrosion properties of SiO2 coatings on copper in geothermal water [texte imprimé] / Chen Ning, Auteur ; Liu Mingyan, Auteur ; Zhou Weidong, Auteur . - 2012 . - pp. 6001–6017. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 17 (Mai 2012) . - pp. 6001–6017 Mots-clés : Geothermal  utilization  Corrosion  Silica  coatings Résumé : Two critical problems in geothermal utilization are corrosion and fouling on the surfaces of plants and fittings, and use of surface coatings is a good method to overcome such difficulties. Silica coatings with film thickness of several hundred nanometers on copper substrates were prepared by the liquid-phase deposition technique and characterized with respect to surface morphology, composition, surface free energy, roughness, and film thickness. Examinations of both fouling in calcium carbonate solution and corrosion in corrosive geothermal water on the surfaces of SiO2-coated samples were performed. The results showed that the fouling rate on the SiO2-coated surface was obviously reduced compared with that on the polished surface. Moreover, the inhibition of corrosion on the modified surface was found even though, after a long immersion time, the corrosion resistance action decreased because of the surface peeling of SiO2-coated samples. The corrosion behavior of the SiO2 coating was further studied with electrochemical measurements by electrochemical impedance spectroscopy. This work suggests a new possibility for solving the fouling and corrosion issues encountered in the use of geothermal water. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie202091b