Documents disponibles écrits par cet auteur

Bubble structures between two walls in ultrasonic cavitation erosion / A. Abouel-Kasem in Transactions of the ASME . Journal of tribology, Vol. 134 N° 2 (Avril 2012) 

Public ISBD [article]  in Transactions of the ASME . Journal of tribology > Vol. 134 N° 2 (Avril 2012) . - 09 p. Titre : Bubble structures between two walls in ultrasonic cavitation erosion Type de document : texte imprimé Auteurs : A. Abouel-Kasem, Auteur ; S. M. Ahmed, Auteur Année de publication : 2012 Article en page(s) : 09 p. Note générale : tribology Langues : Anglais (eng) Mots-clés : cavitation  erosion;  high  speed  imaging;  bubble  structures;  AL-99  999;  fatigue Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : The cavitation bubble structures for the stationary specimen method were clarified for various distances, h, between the stationary specimen and the horn-tip surface. The generated cavitation bubbles constituted a huge number of tiny bubbles and bubble clusters of different sizes. The maximum cluster size was 1.4 mm. The observed cavitation patterns systematically changed during tests from the subcavitating state to the supercavitating state with respect to the separation distance, h. For h <4 mm, the bubbles have a definite trajectory, and the pressure patterns manifest a circular shape as a result of streaming induced by ultrasonic cavitation. The feature morphology of the eroded surfaces revealed that the predominant failure mode was fatigue. In the light of the material failure features and the cavitation patterns, it is also deduced that the important mechanism to transfer the cavitation energy to the solid is shock pressures accompanied by collapsing clusters. DEWEY : 621.5 ISSN : 0742-4787 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JOTRE9000134000002 [...] [article] Bubble structures between two walls in ultrasonic cavitation erosion [texte imprimé] / A. Abouel-Kasem, Auteur ; S. M. Ahmed, Auteur . - 2012 . - 09 p. tribology Langues : Anglais (eng) in Transactions of the ASME . Journal of tribology > Vol. 134 N° 2 (Avril 2012) . - 09 p. Mots-clés : cavitation  erosion;  high  speed  imaging;  bubble  structures;  AL-99  999;  fatigue Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : The cavitation bubble structures for the stationary specimen method were clarified for various distances, h, between the stationary specimen and the horn-tip surface. The generated cavitation bubbles constituted a huge number of tiny bubbles and bubble clusters of different sizes. The maximum cluster size was 1.4 mm. The observed cavitation patterns systematically changed during tests from the subcavitating state to the supercavitating state with respect to the separation distance, h. For h <4 mm, the bubbles have a definite trajectory, and the pressure patterns manifest a circular shape as a result of streaming induced by ultrasonic cavitation. The feature morphology of the eroded surfaces revealed that the predominant failure mode was fatigue. In the light of the material failure features and the cavitation patterns, it is also deduced that the important mechanism to transfer the cavitation energy to the solid is shock pressures accompanied by collapsing clusters. DEWEY : 621.5 ISSN : 0742-4787 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JOTRE9000134000002 [...]

Cavitation erosion mechanism based on analysis of erosion particles / A. Abouel-Kasem in Transactions of the ASME . Journal of tribology, Vol. 130 n°3 (Juillet 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of tribology > Vol. 130 n°3 (Juillet 2008) . - 6 p. Titre : Cavitation erosion mechanism based on analysis of erosion particles Type de document : texte imprimé Auteurs : A. Abouel-Kasem, Auteur ; S. M. Ahmed, Auteur Année de publication : 2008 Article en page(s) : 6 p. Note générale : Tribology Langues : Anglais (eng) Mots-clés : Particulate  matter  Cavitation  erosion  Erosion  Mechanisms  Fatigue Résumé : The mechanism of cavitation erosion is investigated in detail through observations of the removed particles from pure aluminum (Al-99.999). The particles removed during the incubation stage have distinctive characteristics compared to those removed in the subsequent stages. These characteristics are distinguished by lamellae structure, foldness, waviness, large size as well as one of the particle surfaces appeared to be part of the original face of the specimen. Therefore, these characteristics can be used as a monitor for early detection of cavitation erosion in closed systems. Systematic observations of disloged particles and eroded surface morphology show that the dominant failure mode in cavitation erosion is fatigue. En ligne : http://tribology.asmedigitalcollection.asme.org/article.aspx?articleID=1468069 [article] Cavitation erosion mechanism based on analysis of erosion particles [texte imprimé] / A. Abouel-Kasem, Auteur ; S. M. Ahmed, Auteur . - 2008 . - 6 p. Tribology Langues : Anglais (eng) in Transactions of the ASME . Journal of tribology > Vol. 130 n°3 (Juillet 2008) . - 6 p. Mots-clés : Particulate  matter  Cavitation  erosion  Erosion  Mechanisms  Fatigue Résumé : The mechanism of cavitation erosion is investigated in detail through observations of the removed particles from pure aluminum (Al-99.999). The particles removed during the incubation stage have distinctive characteristics compared to those removed in the subsequent stages. These characteristics are distinguished by lamellae structure, foldness, waviness, large size as well as one of the particle surfaces appeared to be part of the original face of the specimen. Therefore, these characteristics can be used as a monitor for early detection of cavitation erosion in closed systems. Systematic observations of disloged particles and eroded surface morphology show that the dominant failure mode in cavitation erosion is fatigue. En ligne : http://tribology.asmedigitalcollection.asme.org/article.aspx?articleID=1468069

Fractal analysis of cavitation eroded surface in dilute emulsions / A. Abouel-Kasem in Transactions of the ASME . Journal of tribology, Vol. 133 N° 4 (Octobre 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of tribology > Vol. 133 N° 4 (Octobre 2011) . - 09 p. Titre : Fractal analysis of cavitation eroded surface in dilute emulsions Type de document : texte imprimé Auteurs : A. Abouel-Kasem, Auteur ; F. A. Alturki, Auteur ; S. M. Ahmed, Auteur Année de publication : 2012 Article en page(s) : 09 p. Note générale : Triboblogy Langues : Anglais (eng) Mots-clés : Emulsions  Fractals  Fracture  Stainless  steel  Water  Wear Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : In the present work, the topographical images of cavitation erosion surfaces at water and oil-in-water (o/w) emulsions were quantified using fractal analysis. The oil-in-water emulsion concentrations were 2, 5 and 10 wt. %, which are in the popular range used in hydraulic systems. The study showed that the variation of fractal dimension calculated from slope of linearized power spectral density for water and o/w emulsions can be used to characterize the cavitation intensity in similar manner to the weight loss. Both the fractal dimension and the weight loss decrease with adding oil to water. It was also found that the variation of fractal dimension versus concentration of oil-in-water emulsions has a general trend that does not depend on magnification factor. The cavitation erosion behavior and mechanism for water and o/w emulsions has been studied. It was found that the predominant failure mode was fatigue for water and o/w emulsions. DEWEY : 621.5 ISSN : 0742-4787 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JOTRE900013 [...] [article] Fractal analysis of cavitation eroded surface in dilute emulsions [texte imprimé] / A. Abouel-Kasem, Auteur ; F. A. Alturki, Auteur ; S. M. Ahmed, Auteur . - 2012 . - 09 p. Triboblogy Langues : Anglais (eng) in Transactions of the ASME . Journal of tribology > Vol. 133 N° 4 (Octobre 2011) . - 09 p. Mots-clés : Emulsions  Fractals  Fracture  Stainless  steel  Water  Wear Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : In the present work, the topographical images of cavitation erosion surfaces at water and oil-in-water (o/w) emulsions were quantified using fractal analysis. The oil-in-water emulsion concentrations were 2, 5 and 10 wt. %, which are in the popular range used in hydraulic systems. The study showed that the variation of fractal dimension calculated from slope of linearized power spectral density for water and o/w emulsions can be used to characterize the cavitation intensity in similar manner to the weight loss. Both the fractal dimension and the weight loss decrease with adding oil to water. It was also found that the variation of fractal dimension versus concentration of oil-in-water emulsions has a general trend that does not depend on magnification factor. The cavitation erosion behavior and mechanism for water and o/w emulsions has been studied. It was found that the predominant failure mode was fatigue for water and o/w emulsions. DEWEY : 621.5 ISSN : 0742-4787 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JOTRE900013 [...]

Quantitative analysis of cavitation erosion particle morphology in dilute emulsions / A. Abouel-Kasem in Transactions of the ASME . Journal of tribology, Vol. 130 N° 4 (Octobre 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of tribology > Vol. 130 N° 4 (Octobre 2008) . - 6 p. Titre : Quantitative analysis of cavitation erosion particle morphology in dilute emulsions Type de document : texte imprimé Auteurs : A. Abouel-Kasem, Auteur ; B. Saleh, Auteur ; S. M. Ahmed, Auteur Année de publication : 2015 Article en page(s) : 6 p. Note générale : Tribology Langues : Anglais (eng) Mots-clés : Wear  Particulate  matter  Cavitation  erosion  Emulsions  Shapes  Water  Mechanisms  Elongation Résumé : Wear particles produced by vibratory cavitation erosion tests on 1017 carbon steels in water and oil-in-water (o∕w) emulsions were analyzed. Scanning electron microscope (SEM) images of wear particles were acquired, forming a database for further analysis. The particle morphology features were first clarified. Next, the size parameters (size, area, and perimeter) and shape factors (elongation and roundness) were determined for each test liquid, using image analysis software. The size parameters of the removed particles were higher in water than in o∕w emulsions. While the shape factors could not significantly discriminate between the particles produced in water and o∕w emulsions. The size distribution was in a wide range for water than that for o∕w emulsions. The cavitation erosion mechanism is fatigue failure for water and o∕w emulsions. En ligne : http://tribology.asmedigitalcollection.asme.org/article.aspx?articleid=1468120 [article] Quantitative analysis of cavitation erosion particle morphology in dilute emulsions [texte imprimé] / A. Abouel-Kasem, Auteur ; B. Saleh, Auteur ; S. M. Ahmed, Auteur . - 2015 . - 6 p. Tribology Langues : Anglais (eng) in Transactions of the ASME . Journal of tribology > Vol. 130 N° 4 (Octobre 2008) . - 6 p. Mots-clés : Wear  Particulate  matter  Cavitation  erosion  Emulsions  Shapes  Water  Mechanisms  Elongation Résumé : Wear particles produced by vibratory cavitation erosion tests on 1017 carbon steels in water and oil-in-water (o∕w) emulsions were analyzed. Scanning electron microscope (SEM) images of wear particles were acquired, forming a database for further analysis. The particle morphology features were first clarified. Next, the size parameters (size, area, and perimeter) and shape factors (elongation and roundness) were determined for each test liquid, using image analysis software. The size parameters of the removed particles were higher in water than in o∕w emulsions. While the shape factors could not significantly discriminate between the particles produced in water and o∕w emulsions. The size distribution was in a wide range for water than that for o∕w emulsions. The cavitation erosion mechanism is fatigue failure for water and o∕w emulsions. En ligne : http://tribology.asmedigitalcollection.asme.org/article.aspx?articleid=1468120