Documents disponibles écrits par cet auteur

An experimental study of the correlation for predicting the frost height in applying the photoelectric technology / J. Xiao in International journal of refrigeration, Vol. 33 N° 5 (Août 2010) 

Public ISBD [article]  in International journal of refrigeration > Vol. 33 N° 5 (Août 2010) . - pp. 1006-1014 Titre : An experimental study of the correlation for predicting the frost height in applying the photoelectric technology Titre original : Etude expérimentale sur la corrélation de la prévision de l'accumulation de givre dans l'application de la technologie photoélectrique Type de document : texte imprimé Auteurs : J. Xiao, Auteur ; Wang, W., Auteur ; Q.C. Guo, Auteur Année de publication : 2010 Article en page(s) : pp. 1006-1014 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Refrigeration  system  Heat  exchanger  Finned  tube  Experiment  Measurement  Frost  formation  Sensor-infrared Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : It is found that the photoelectric technology is suitable for the accurate measurement of the frost height. The objectives of this paper are to experimentally investigate the correspondence between the output signal of the photoelectric sensor and the frost height, and then develop a generalized correlation to predict the frost height directly and accurately. The experiments are conducted in a wide range of operating conditions for air temperature 17.7 °C–27.2 °C, relative humidity 21.6% RH to 64.9% RH, air velocity 0.5 m/s to 4.5 m/s and cold surface temperature −10.5 °C to −6.5 °C. Based on 21 groups of experiments with total 600 data, a linear correlation with a relative deviation of ±10% is setup. Further validation of this correlation is conducted by comparing the predicted results with 4 additional experiments, and approximately 95% of the predicted frost heights are consistent with the measured data within a relative deviation of ±10%. These results indicate that the photoelectric technology can predict the frost height directly. The application of the proposed correlation to provide defrost control strategy is also discussed in this paper. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710000484 [article] An experimental study of the correlation for predicting the frost height in applying the photoelectric technology = Etude expérimentale sur la corrélation de la prévision de l'accumulation de givre dans l'application de la technologie photoélectrique [texte imprimé] / J. Xiao, Auteur ; Wang, W., Auteur ; Q.C. Guo, Auteur . - 2010 . - pp. 1006-1014. Génie Mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 33 N° 5 (Août 2010) . - pp. 1006-1014 Mots-clés : Refrigeration  system  Heat  exchanger  Finned  tube  Experiment  Measurement  Frost  formation  Sensor-infrared Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : It is found that the photoelectric technology is suitable for the accurate measurement of the frost height. The objectives of this paper are to experimentally investigate the correspondence between the output signal of the photoelectric sensor and the frost height, and then develop a generalized correlation to predict the frost height directly and accurately. The experiments are conducted in a wide range of operating conditions for air temperature 17.7 °C–27.2 °C, relative humidity 21.6% RH to 64.9% RH, air velocity 0.5 m/s to 4.5 m/s and cold surface temperature −10.5 °C to −6.5 °C. Based on 21 groups of experiments with total 600 data, a linear correlation with a relative deviation of ±10% is setup. Further validation of this correlation is conducted by comparing the predicted results with 4 additional experiments, and approximately 95% of the predicted frost heights are consistent with the measured data within a relative deviation of ±10%. These results indicate that the photoelectric technology can predict the frost height directly. The application of the proposed correlation to provide defrost control strategy is also discussed in this paper. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710000484

Corrosion behavior of hydrophobic titanium oxide film pre-treated in hydrogen peroxide solution / M. Wang in Materials and corrosion, Vol. 62 N° 4 (Avril 2011) 

Public ISBD [article]  in Materials and corrosion > Vol. 62 N° 4 (Avril 2011) . - pp. 320–325 Titre : Corrosion behavior of hydrophobic titanium oxide film pre-treated in hydrogen peroxide solution Type de document : texte imprimé Auteurs : M. Wang, Auteur ; Wang, W., Auteur ; B. L. He, Auteur Année de publication : 2011 Article en page(s) : pp. 320–325 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Corrosion  resistance  EIS  Hydrophobic  Surface  morphology  Titanium  oxide Résumé : Hydrophobic titanium oxide (TiO2) film formed on metallic titanium substrate in hydrogen peroxide solution with a subsequent oxidation under air atmosphere. Component, microstructure, and hydrophobicity of the oxide film were characterized by X-ray diffraction, scanning electron microscope, and water contact angle methods. Corrosion resistance tests were carried out in seawater solution at different heating temperature conditions. Electrochemical impedance spectroscopy techniques and polarization curves were used to study the changes and the corrosion resistance of the TiO2 film. The results demonstrate that the pre-treated TiO2 film heated at 400 °C environment owns small special groove-shaped structure on its surface, which induce higher hydrophobic capability, larger impedance, and better electrochemical stability than the film that was prepared at other temperatures or the Ti with nature formed oxidation film. It would be an ideal candidate as engineering material in deep seawater environment. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905451/abstract [article] Corrosion behavior of hydrophobic titanium oxide film pre-treated in hydrogen peroxide solution [texte imprimé] / M. Wang, Auteur ; Wang, W., Auteur ; B. L. He, Auteur . - 2011 . - pp. 320–325. Génie Mécanique Langues : Anglais (eng) in Materials and corrosion > Vol. 62 N° 4 (Avril 2011) . - pp. 320–325 Mots-clés : Corrosion  resistance  EIS  Hydrophobic  Surface  morphology  Titanium  oxide Résumé : Hydrophobic titanium oxide (TiO2) film formed on metallic titanium substrate in hydrogen peroxide solution with a subsequent oxidation under air atmosphere. Component, microstructure, and hydrophobicity of the oxide film were characterized by X-ray diffraction, scanning electron microscope, and water contact angle methods. Corrosion resistance tests were carried out in seawater solution at different heating temperature conditions. Electrochemical impedance spectroscopy techniques and polarization curves were used to study the changes and the corrosion resistance of the TiO2 film. The results demonstrate that the pre-treated TiO2 film heated at 400 °C environment owns small special groove-shaped structure on its surface, which induce higher hydrophobic capability, larger impedance, and better electrochemical stability than the film that was prepared at other temperatures or the Ti with nature formed oxidation film. It would be an ideal candidate as engineering material in deep seawater environment. DEWEY : 620.1 ISSN : 0947-5117 En ligne : http://onlinelibrary.wiley.com/doi/10.1002/maco.200905451/abstract

Genetic design and characterization of novel ultra-high-strength stainless steels strengthened by Ni3Ti intermetallic nanoprecipitates / W. Xu in Acta materialia, Vol. 58 N° 10 (Juin 2010) 

Public ISBD [article]  in Acta materialia > Vol. 58 N° 10 (Juin 2010) . - pp. 3582–3593 Titre : Genetic design and characterization of novel ultra-high-strength stainless steels strengthened by Ni3Ti intermetallic nanoprecipitates Type de document : texte imprimé Auteurs : W. Xu, Auteur ; P.E.J. Rivera-Díaz-del-Castillo, Auteur ; Wang, W., Auteur Année de publication : 2011 Article en page(s) : pp. 3582–3593 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : Maraging  steels  Stainless  steels  Thermodynamics  Precipitation  Alloy  design Résumé : A general computational alloy design approach based on thermodynamic and physical metallurgical principles, and coupled with a genetic optimization scheme, is presented. The method is applied to the design of new ultra-high-strength maraging stainless steels strengthened by Ni3Ti intermetallics. In the first design round, the alloy composition is optimized on the basis of precipitate formation at a fixed ageing temperature without considering other steps in the heat treatment. In the second round, the alloy is redesigned, applying an integrated model which allows for the simultaneous optimization of alloy composition and the ageing temperature as well as the prior austenitization temperature. The experimental characterizations of prototype alloys clearly demonstrate that alloys designed by the proposed approach achieve the desired microstructures. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S135964541000114X [article] Genetic design and characterization of novel ultra-high-strength stainless steels strengthened by Ni3Ti intermetallic nanoprecipitates [texte imprimé] / W. Xu, Auteur ; P.E.J. Rivera-Díaz-del-Castillo, Auteur ; Wang, W., Auteur . - 2011 . - pp. 3582–3593. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 58 N° 10 (Juin 2010) . - pp. 3582–3593 Mots-clés : Maraging  steels  Stainless  steels  Thermodynamics  Precipitation  Alloy  design Résumé : A general computational alloy design approach based on thermodynamic and physical metallurgical principles, and coupled with a genetic optimization scheme, is presented. The method is applied to the design of new ultra-high-strength maraging stainless steels strengthened by Ni3Ti intermetallics. In the first design round, the alloy composition is optimized on the basis of precipitate formation at a fixed ageing temperature without considering other steps in the heat treatment. In the second round, the alloy is redesigned, applying an integrated model which allows for the simultaneous optimization of alloy composition and the ageing temperature as well as the prior austenitization temperature. The experimental characterizations of prototype alloys clearly demonstrate that alloys designed by the proposed approach achieve the desired microstructures. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S135964541000114X

Maintenance models based on the np control charts with respect to the sampling interval / Wang, W. in Journal of the operational research society (JORS), Vol. 62 N° 1 (Janvier 2011) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 62 N° 1 (Janvier 2011) . - pp. 124–133 Titre : Maintenance models based on the np control charts with respect to the sampling interval Type de document : texte imprimé Auteurs : Wang, W., Auteur Année de publication : 2011 Article en page(s) : pp. 124–133 Note générale : Recherche opérationnelle Langues : Anglais (eng) Mots-clés : Sampling  interval  Maintenance  schedule  Control  chart  Repairable  system  Geometric  processes Index. décimale : 001.424 Résumé : This paper develops models for the maintenance of a system based on np control charts with respect to the sampling interval. At any given time, the system is assumed to be in one of the three possible states; in-control, out-of-control and failure. If the control chart signals, suggesting the possibility of an out-of-control state, an investigation will be carried out. We assume that this investigation is perfect in that it reveals the true state of the system. If an assignable cause is confirmed by the investigation, a minor repair will be carried out to remove the cause. If the assignable cause is not attended to, it will gradually develop into a failure. When a failure occurs, the system cannot operate and a major repair is needed. We discuss three models depending on the assumptions related to the renewal mechanism, the occurrence of failures, and the time between minor repairs. The paper seeks to optimise the performance of such a system in terms of the sampling interval. Geometric processes are utilised for modelling the lifetimes between minor repairs if the minor repair cannot bring the system back to an as good as new condition. The expected cost per unit time for maintaining the systems with respect to the sampling interval of the control chart is obtained. Numerical examples are conducted to demonstrate the applicability of the methodology derived. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n1/abs/jors2009165a.html [article] Maintenance models based on the np control charts with respect to the sampling interval [texte imprimé] / Wang, W., Auteur . - 2011 . - pp. 124–133. Recherche opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 62 N° 1 (Janvier 2011) . - pp. 124–133 Mots-clés : Sampling  interval  Maintenance  schedule  Control  chart  Repairable  system  Geometric  processes Index. décimale : 001.424 Résumé : This paper develops models for the maintenance of a system based on np control charts with respect to the sampling interval. At any given time, the system is assumed to be in one of the three possible states; in-control, out-of-control and failure. If the control chart signals, suggesting the possibility of an out-of-control state, an investigation will be carried out. We assume that this investigation is perfect in that it reveals the true state of the system. If an assignable cause is confirmed by the investigation, a minor repair will be carried out to remove the cause. If the assignable cause is not attended to, it will gradually develop into a failure. When a failure occurs, the system cannot operate and a major repair is needed. We discuss three models depending on the assumptions related to the renewal mechanism, the occurrence of failures, and the time between minor repairs. The paper seeks to optimise the performance of such a system in terms of the sampling interval. Geometric processes are utilised for modelling the lifetimes between minor repairs if the minor repair cannot bring the system back to an as good as new condition. The expected cost per unit time for maintaining the systems with respect to the sampling interval of the control chart is obtained. Numerical examples are conducted to demonstrate the applicability of the methodology derived. DEWEY : 001.424 ISSN : 0160-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v62/n1/abs/jors2009165a.html