Documents disponibles écrits par cet auteur

An experimental study on the oblique collisions of water droplets with a smooth hot solid / Hiroshi Fujimoto 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) . - 12 p. Titre : An experimental study on the oblique collisions of water droplets with a smooth hot solid Type de document : texte imprimé Auteurs : Hiroshi Fujimoto, Auteur ; Ryota Doi, Auteur ; Hirohiko Takuda, Auteur Année de publication : 2012 Article en page(s) : 12 p. Note générale : fluids engineering Langues : Anglais (eng) Mots-clés : oblique  collision;  weber  number;  two-directional  flash  photography;  dynamical  similarity;  droplet Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The motions of liquid droplets impinging on a solid substrate have been studied experimentally in fundamental research on various types of industrial applications, including spray cooling. The oblique collision of a single water droplet with a hot Inconel 625 alloy surface has been investigated by means of a two-directional flash photography technique that uses two digital still cameras and three flash units. The experiments were conducted under the following conditions. The preimpact diameter of the droplets was approximately 0.6 mm, the impact velocity was 1.9–3.1 m/s, and the temperature of the Inconel 625 alloy surface ranged from 170 °C to 500 °C. The impact angle of droplets on the solid surface was in the range 45 deg–90 deg. Experiments using 2.5 mm diameter droplets at an impact velocity of 0.84–1.4 m/s were also conducted at the surface temperature of 500 °C. At surface temperatures of 200 °C, 300 °C, and 400 °C, the droplet deforms into an asymmetric shape and moves downward along the tilted surface. Numerous secondary droplets jet upward from the deforming droplet as a result of the blowout of vapor bubbles into the atmosphere. At a surface temperature of 500 °C and a low Weber number Wen based on the normal velocity component to the solid surface, no secondary droplets are observed. The droplet rebounds off the solid without disintegrating. The droplet becomes almost axisymmetric in shape during the collision regardless of the impact angle. The dimensionless collision behaviors of large and small droplets were similar for the same Wen when the temperature was 500 °C. Using Wen, we investigated the deformation characteristics of droplets in oblique collisions. DEWEY : 620.1 ISSN : 0098-2202 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JFEGA4000134000007 [...] [article] An experimental study on the oblique collisions of water droplets with a smooth hot solid [texte imprimé] / Hiroshi Fujimoto, Auteur ; Ryota Doi, Auteur ; Hirohiko Takuda, Auteur . - 2012 . - 12 p. fluids engineering Langues : Anglais (eng) in Transactions of the ASME . Journal of fluids engineering > Vol. 134 N° 7 (Juillet 2012) . - 12 p. Mots-clés : oblique  collision;  weber  number;  two-directional  flash  photography;  dynamical  similarity;  droplet Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The motions of liquid droplets impinging on a solid substrate have been studied experimentally in fundamental research on various types of industrial applications, including spray cooling. The oblique collision of a single water droplet with a hot Inconel 625 alloy surface has been investigated by means of a two-directional flash photography technique that uses two digital still cameras and three flash units. The experiments were conducted under the following conditions. The preimpact diameter of the droplets was approximately 0.6 mm, the impact velocity was 1.9–3.1 m/s, and the temperature of the Inconel 625 alloy surface ranged from 170 °C to 500 °C. The impact angle of droplets on the solid surface was in the range 45 deg–90 deg. Experiments using 2.5 mm diameter droplets at an impact velocity of 0.84–1.4 m/s were also conducted at the surface temperature of 500 °C. At surface temperatures of 200 °C, 300 °C, and 400 °C, the droplet deforms into an asymmetric shape and moves downward along the tilted surface. Numerous secondary droplets jet upward from the deforming droplet as a result of the blowout of vapor bubbles into the atmosphere. At a surface temperature of 500 °C and a low Weber number Wen based on the normal velocity component to the solid surface, no secondary droplets are observed. The droplet rebounds off the solid without disintegrating. The droplet becomes almost axisymmetric in shape during the collision regardless of the impact angle. The dimensionless collision behaviors of large and small droplets were similar for the same Wen when the temperature was 500 °C. Using Wen, we investigated the deformation characteristics of droplets in oblique collisions. DEWEY : 620.1 ISSN : 0098-2202 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JFEGA4000134000007 [...]

RRO compensation of hard disk drives with multirate repetitive perfect tracking control / Hiroshi Fujimoto in IEEE transactions on industrial electronics, Vol. 56 N° 10 (Octobre 2009) 

Public ISBD [article]  in IEEE transactions on industrial electronics > Vol. 56 N° 10 (Octobre 2009) . - pp. 3825 - 3831 Titre : RRO compensation of hard disk drives with multirate repetitive perfect tracking control Type de document : texte imprimé Auteurs : Hiroshi Fujimoto, Auteur Article en page(s) : pp. 3825 - 3831 Note générale : Génie electrique Langues : Anglais (eng) Mots-clés : Hard  disks  Motion  control  Multirate  control Index. décimale : 621.38 Dispositifs électroniques. Tubes à électrons. Photocellules. Accélérateurs de particules. Tubes à rayons X Résumé : In this paper, novel repetitive controllers are proposed based on perfect tracking control (PTC) in order to reject high-order repeatable runout (RRO) of hard disk drives. First, the feedback approach of the repetitive PTC (RPTC) is developed with internal model of periodic disturbance. Although this method has performance robustness against small plant variation, the internal model worsens the stability robustness for big modeling error. Then, the feedforward (FF) approach of RPTC is introduced with switching mechanism such that the high-order RRO can be rejected without any sacrifice of the closed-loop characteristics. In both approaches, multirate FF control is utilized to overcome the unstable zero problem of discrete-time plant. Finally, the advantages and disadvantages are demonstrated through simulations and experiments. DEWEY : 621.38 ISSN : 0278-0046 En ligne : http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=4804798 [article] RRO compensation of hard disk drives with multirate repetitive perfect tracking control [texte imprimé] / Hiroshi Fujimoto, Auteur . - pp. 3825 - 3831. Génie electrique Langues : Anglais (eng) in IEEE transactions on industrial electronics > Vol. 56 N° 10 (Octobre 2009) . - pp. 3825 - 3831 Mots-clés : Hard  disks  Motion  control  Multirate  control Index. décimale : 621.38 Dispositifs électroniques. Tubes à électrons. Photocellules. Accélérateurs de particules. Tubes à rayons X Résumé : In this paper, novel repetitive controllers are proposed based on perfect tracking control (PTC) in order to reject high-order repeatable runout (RRO) of hard disk drives. First, the feedback approach of the repetitive PTC (RPTC) is developed with internal model of periodic disturbance. Although this method has performance robustness against small plant variation, the internal model worsens the stability robustness for big modeling error. Then, the feedforward (FF) approach of RPTC is introduced with switching mechanism such that the high-order RRO can be rejected without any sacrifice of the closed-loop characteristics. In both approaches, multirate FF control is utilized to overcome the unstable zero problem of discrete-time plant. Finally, the advantages and disadvantages are demonstrated through simulations and experiments. DEWEY : 621.38 ISSN : 0278-0046 En ligne : http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=4804798

Theoretical study of medium-sized azacycloalkane and dialkyl amine adsorption on the Fe(111) surface / Shinichi Satoh in Industrial & engineering chemistry research, Vol. 50 N° 12 (Juin 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 12 (Juin 2011) . - pp. 7313-7318 Titre : Theoretical study of medium-sized azacycloalkane and dialkyl amine adsorption on the Fe(111) surface Type de document : texte imprimé Auteurs : Shinichi Satoh, Auteur ; Hiroshi Fujimoto, Auteur Année de publication : 2011 Article en page(s) : pp. 7313-7318 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Adsorption Résumé : To understand the difference in inhibition efficiency against corrosion of iron surfaces between medium-sized azacycloalkanes and dialkyl amines containing the same number of carbon atoms, the adsorption of azacycloundecane and of dipentyl amine onto a model Fe(111) surface has been studied using the molecular orbital and density functional theoretical methods. B3LYP calculations show that azacycloundecane gives a stronger interaction with the surface from an energy point of view. The difference between the two amines in the strength of interaction originates predominantly from the changes in structure of the carbon chains that take place during the adsorption process. The calculations suggest that a large C-N-C bond angle does not lead to efficient secondary-amine inhibitors that prevent the corrosion of iron surfaces. This conclusion is supported by a paired interaction orbital analysis. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24239045 [article] Theoretical study of medium-sized azacycloalkane and dialkyl amine adsorption on the Fe(111) surface [texte imprimé] / Shinichi Satoh, Auteur ; Hiroshi Fujimoto, Auteur . - 2011 . - pp. 7313-7318. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 12 (Juin 2011) . - pp. 7313-7318 Mots-clés : Adsorption Résumé : To understand the difference in inhibition efficiency against corrosion of iron surfaces between medium-sized azacycloalkanes and dialkyl amines containing the same number of carbon atoms, the adsorption of azacycloundecane and of dipentyl amine onto a model Fe(111) surface has been studied using the molecular orbital and density functional theoretical methods. B3LYP calculations show that azacycloundecane gives a stronger interaction with the surface from an energy point of view. The difference between the two amines in the strength of interaction originates predominantly from the changes in structure of the carbon chains that take place during the adsorption process. The calculations suggest that a large C-N-C bond angle does not lead to efficient secondary-amine inhibitors that prevent the corrosion of iron surfaces. This conclusion is supported by a paired interaction orbital analysis. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24239045