The Experts below are selected from a list of 75 Experts worldwide ranked by ideXlab platform

Ali Dolatabadi - One of the best experts on this subject based on the ideXlab platform.

  • Predictive Model of Supercooled Water Droplet Pinning/Repulsion Impacting a Superhydrophobic Surface: The Role of the Gas–Liquid Interface Temperature
    Langmuir : the ACS journal of surfaces and colloids, 2017
    Co-Authors: Morteza Mohammadi, Moussa Tembely, Ali Dolatabadi
    Abstract:

    Dynamical analysis of an impacting liquid drop on superhydrophobic surfaces is mostly carried out by evaluating the droplet contact time and maximum spreading diameter. In this study, we present a general transient model of the droplet spreading diameter developed from the previously defined mass–spring model for bouncing drops. The effect of viscosity was also considered in the model by definition of a dash-pot term extracted from experiments on various viscous liquid droplets on a superhydrophobic surface. Furthermore, the Resultant Shear Force of the stagnation air flow was also considered with the help of the classical Homann flow approach. It was clearly shown that the proposed model predicts the maximum spreading diameter and droplet contact time very well. On the other hand, where stagnation air flow is present in contradiction to the theoretical model, the droplet contact time was reduced as a function of both droplet Weber numbers and incoming air velocities. Indeed, the reduction in the droplet ...

  • Predictive Model of Supercooled Water Droplet Pinning/Repulsion Impacting a Superhydrophobic Surface: The Role of the Gas–Liquid Interface Temperature
    2017
    Co-Authors: Morteza Mohammadi, Moussa Tembely, Ali Dolatabadi
    Abstract:

    Dynamical analysis of an impacting liquid drop on superhydrophobic surfaces is mostly carried out by evaluating the droplet contact time and maximum spreading diameter. In this study, we present a general transient model of the droplet spreading diameter developed from the previously defined mass–spring model for bouncing drops. The effect of viscosity was also considered in the model by definition of a dash-pot term extracted from experiments on various viscous liquid droplets on a superhydrophobic surface. Furthermore, the Resultant Shear Force of the stagnation air flow was also considered with the help of the classical Homann flow approach. It was clearly shown that the proposed model predicts the maximum spreading diameter and droplet contact time very well. On the other hand, where stagnation air flow is present in contradiction to the theoretical model, the droplet contact time was reduced as a function of both droplet Weber numbers and incoming air velocities. Indeed, the reduction in the droplet contact time (e.g., 35% at a droplet Weber number of up to 140) was justified by the presence of a formed thin air layer underneath the impacting drop on the superhydrophobic surface (i.e., full slip condition). Finally, the droplet wetting model was also further developed to account for low temperature through the incorporation of classical nucleation theory. Homogeneous ice nucleation was integrated into the model through the concept of the reduction of the supercooled water drop surface tension as a function of the gas–liquid interface temperature, which was directly correlated with the Nusselt number of incoming air flow. It was shown that the experimental results was qualitatively predicted by the proposed model under all supercooling conditions (i.e., from −10 to −30 °C)

Peter Mark - One of the best experts on this subject based on the ideXlab platform.

  • Truss Models for the Design of ReinForced Concrete Beams Subject to Biaxial Shear
    Structures Congress 2005, 2005
    Co-Authors: Peter Mark
    Abstract:

    Spatial truss models are developed for the design of reinForced concrete beams subject to biaxial Shear Forces. They are derived from a resolution of the vector of the Resultant Shear Force and applied to beams with rectangular cross sections. The models consist of tensile struts of stirrups and longitudinal bars, spatially inclined Shear struts as well as compressive struts stiffening the stirrup corners. They are further elaborated to derive charts for the stirrup design. An example shows the practical application.

  • Stahlbetontraeger mit zweiachsiger Querkraftbeanspruchung. Fachwerkmodelle, Experiment und Bemessungsansatz / ReinForced concrete beams subject to biaxial Shear Forces: strut-and-tie models, experiment and design approach
    Beton- Und Stahlbetonbau, 2004
    Co-Authors: Peter Mark
    Abstract:

    Fuer die Schubbemessung von Stahlbetontraegern mit zweiachsiger Querkraftbeanspruchung werden raeumliche Fachwerkmodelle entwickelt. Dazu wird der Vektor der resultierenden Querkraft in Einzelanteile aufgeteilt und damit die schraege Betondruckstrebe in Einzelstreben aufgeloest. Die Modelle gelten fuer Stahlbetontraeger mit Rechteckquerschnitt und bestehen aus Zugstreben von Buegeln und Laengsstaeben, allgemein raeumlichen Betondruckstreben sowie aussteifenden Druckstreben in Buegelebene. Sie werden an Experimenten qualitativ verifiziert und zur Ableitung von Bemessungsdiagrammen fuer die Buegelbemessung erweitert. Ein Beispiel zeigt die praktische Anwendung der Diagramme. (A) ABSTRACT IN ENGLISH: Spatial strut-and-tie models are developed for the design of reinForced concrete beams subject to biaxial Shear Forces. They are derived from a resolution of the vector of the Resultant Shear Force and valid for beams with rectangular cross sections. The models consist of tensile struts of stirrups and longitudinal bars, compressive concrete struts directed to each separate area of the longitudinal reinForcement in the cracked part of the cross section as well as compressive struts stiffening the stirrups. They are qualitatively verified by experiments and further elaborated to derive design charts for the design of the stirrups. An example shows the practical application of the charts. (A)

  • Stahlbetonträger mit zweiachsiger Querkraftbeanspruchung
    Beton- und Stahlbetonbau, 2004
    Co-Authors: Peter Mark
    Abstract:

    Fur die Schubbemessung von Stahlbetontragern mit zweiachsiger Querkraftbeanspruchung werden raumliche Fachwerkmodelle entwickelt. Dazu wird der Vektor der resultierenden Querkraft in Einzelanteile aufgeteilt und damit die schrage Betondruckstrebe in Einzelstreben aufgelost. Die Modelle gelten fur Stahlbetontrager mit Rechteckquerschnitt und bestehen aus Zugstreben von Bugeln und Langsstaben, allgemein raumlichen Betondruckstreben sowie aussteifenden Druckstreben in Bugelebene. Sie werden an Experimenten qualitativ verifiziert und zur Ableitung von Bemessungsdiagrammen fur die Bugelbemessung erweitert. Ein Beispiel zeigt die praktische Anwendung der Diagramme. ReinForced Concrete Beams subject to biaxial Shear Forces: strut-and-tie models, experiment and design approach Spatial strut-and-tie models are developed for the design of reinForced concrete beams subject to biaxial Shear Forces. They are derived from a resolution of the vector of the Resultant Shear Force and valid for beams with rectangular cross sections. The models consist of tensile struts of stirrups and longitudinal bars, compressive concrete struts directed to each separate area of the longitudinal reinForcement in the cracked part of the cross section as well as compressive struts stiffening the stirrups. They are qualitatively verified by experiments and further elaborated to derive design charts for the design of the stirrups. An example shows the practical application of the charts.

Morteza Mohammadi - One of the best experts on this subject based on the ideXlab platform.

  • Predictive Model of Supercooled Water Droplet Pinning/Repulsion Impacting a Superhydrophobic Surface: The Role of the Gas–Liquid Interface Temperature
    Langmuir : the ACS journal of surfaces and colloids, 2017
    Co-Authors: Morteza Mohammadi, Moussa Tembely, Ali Dolatabadi
    Abstract:

    Dynamical analysis of an impacting liquid drop on superhydrophobic surfaces is mostly carried out by evaluating the droplet contact time and maximum spreading diameter. In this study, we present a general transient model of the droplet spreading diameter developed from the previously defined mass–spring model for bouncing drops. The effect of viscosity was also considered in the model by definition of a dash-pot term extracted from experiments on various viscous liquid droplets on a superhydrophobic surface. Furthermore, the Resultant Shear Force of the stagnation air flow was also considered with the help of the classical Homann flow approach. It was clearly shown that the proposed model predicts the maximum spreading diameter and droplet contact time very well. On the other hand, where stagnation air flow is present in contradiction to the theoretical model, the droplet contact time was reduced as a function of both droplet Weber numbers and incoming air velocities. Indeed, the reduction in the droplet ...

  • Predictive Model of Supercooled Water Droplet Pinning/Repulsion Impacting a Superhydrophobic Surface: The Role of the Gas–Liquid Interface Temperature
    2017
    Co-Authors: Morteza Mohammadi, Moussa Tembely, Ali Dolatabadi
    Abstract:

    Dynamical analysis of an impacting liquid drop on superhydrophobic surfaces is mostly carried out by evaluating the droplet contact time and maximum spreading diameter. In this study, we present a general transient model of the droplet spreading diameter developed from the previously defined mass–spring model for bouncing drops. The effect of viscosity was also considered in the model by definition of a dash-pot term extracted from experiments on various viscous liquid droplets on a superhydrophobic surface. Furthermore, the Resultant Shear Force of the stagnation air flow was also considered with the help of the classical Homann flow approach. It was clearly shown that the proposed model predicts the maximum spreading diameter and droplet contact time very well. On the other hand, where stagnation air flow is present in contradiction to the theoretical model, the droplet contact time was reduced as a function of both droplet Weber numbers and incoming air velocities. Indeed, the reduction in the droplet contact time (e.g., 35% at a droplet Weber number of up to 140) was justified by the presence of a formed thin air layer underneath the impacting drop on the superhydrophobic surface (i.e., full slip condition). Finally, the droplet wetting model was also further developed to account for low temperature through the incorporation of classical nucleation theory. Homogeneous ice nucleation was integrated into the model through the concept of the reduction of the supercooled water drop surface tension as a function of the gas–liquid interface temperature, which was directly correlated with the Nusselt number of incoming air flow. It was shown that the experimental results was qualitatively predicted by the proposed model under all supercooling conditions (i.e., from −10 to −30 °C)

Moussa Tembely - One of the best experts on this subject based on the ideXlab platform.

  • Predictive Model of Supercooled Water Droplet Pinning/Repulsion Impacting a Superhydrophobic Surface: The Role of the Gas–Liquid Interface Temperature
    Langmuir : the ACS journal of surfaces and colloids, 2017
    Co-Authors: Morteza Mohammadi, Moussa Tembely, Ali Dolatabadi
    Abstract:

    Dynamical analysis of an impacting liquid drop on superhydrophobic surfaces is mostly carried out by evaluating the droplet contact time and maximum spreading diameter. In this study, we present a general transient model of the droplet spreading diameter developed from the previously defined mass–spring model for bouncing drops. The effect of viscosity was also considered in the model by definition of a dash-pot term extracted from experiments on various viscous liquid droplets on a superhydrophobic surface. Furthermore, the Resultant Shear Force of the stagnation air flow was also considered with the help of the classical Homann flow approach. It was clearly shown that the proposed model predicts the maximum spreading diameter and droplet contact time very well. On the other hand, where stagnation air flow is present in contradiction to the theoretical model, the droplet contact time was reduced as a function of both droplet Weber numbers and incoming air velocities. Indeed, the reduction in the droplet ...

  • Predictive Model of Supercooled Water Droplet Pinning/Repulsion Impacting a Superhydrophobic Surface: The Role of the Gas–Liquid Interface Temperature
    2017
    Co-Authors: Morteza Mohammadi, Moussa Tembely, Ali Dolatabadi
    Abstract:

    Dynamical analysis of an impacting liquid drop on superhydrophobic surfaces is mostly carried out by evaluating the droplet contact time and maximum spreading diameter. In this study, we present a general transient model of the droplet spreading diameter developed from the previously defined mass–spring model for bouncing drops. The effect of viscosity was also considered in the model by definition of a dash-pot term extracted from experiments on various viscous liquid droplets on a superhydrophobic surface. Furthermore, the Resultant Shear Force of the stagnation air flow was also considered with the help of the classical Homann flow approach. It was clearly shown that the proposed model predicts the maximum spreading diameter and droplet contact time very well. On the other hand, where stagnation air flow is present in contradiction to the theoretical model, the droplet contact time was reduced as a function of both droplet Weber numbers and incoming air velocities. Indeed, the reduction in the droplet contact time (e.g., 35% at a droplet Weber number of up to 140) was justified by the presence of a formed thin air layer underneath the impacting drop on the superhydrophobic surface (i.e., full slip condition). Finally, the droplet wetting model was also further developed to account for low temperature through the incorporation of classical nucleation theory. Homogeneous ice nucleation was integrated into the model through the concept of the reduction of the supercooled water drop surface tension as a function of the gas–liquid interface temperature, which was directly correlated with the Nusselt number of incoming air flow. It was shown that the experimental results was qualitatively predicted by the proposed model under all supercooling conditions (i.e., from −10 to −30 °C)

Hans Conrad - One of the best experts on this subject based on the ideXlab platform.

  • An analytical model for magnetorheological fluids
    Journal of Physics D: Applied Physics, 2000
    Co-Authors: X. Tang, Hans Conrad
    Abstract:

    Two- and three-dimensional analytical models for the yield stress of magnetorheological (MR) fluids as a function of magnetic field and total volume fraction of particles are developed, which are in accord with experimental data. Important factors are the packing density of the particles in the aggregates, their magnetization saturation and the enhanced field between the particles. Our calculations indicate that the torsional Force components due to the anisotropic magnetizability of the entire MR suspension may contribute up to 20% of the Resultant Shear Force. Further, when the particles are completely saturated the yield stress is proportional to the square of the saturation magnetization.