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Pulak Dutta - One of the best experts on this subject based on the ideXlab platform.

  • Surface order in cold Liquids: X-ray reflectivity studies of Dielectric Liquids and comparison to liquid metals
    Physical Review B, 2010
    Co-Authors: Sudeshna Chattopadhyay, Benjamin Stripe, Evguenia A. Karapetrova, Ahmet Uysal, Steven N. Ehrlich, Pulak Dutta
    Abstract:

    Oscillatory surface-density profiles layers have previously been reported in several metallic Liquids, one Dielectric liquid, and in computer simulations of Dielectric Liquids. We have now seen surface layers in two other Dielectric Liquids, pentaphenyl trimethyl trisiloxane, and pentavinyl pentamethyl cyclopentasiloxane. These layers appear below T?285 K and T?130 K, respectively; both thresholds correspond to T/Tc?0.2 where Tc is the liquid-gas critical temperature. All metallic and Dielectric liquid surfaces previously studied are also consistent with the existence of this T/Tc threshold, first indicated by the simulations of Chacon et al. The layer width parameters, determined using a distorted-crystal fitting model, follow common trends as functions of Tc for both metallic and Dielectric Liquids.

  • Surface order in cold Liquids: X-ray reflectivity studies of Dielectric Liquids and comparison to liquid metals
    Physical Review B - Condensed Matter and Materials Physics, 2010
    Co-Authors: Sudeshna Chattopadhyay, Benjamin Stripe, Steven Ehrlich, Evguenia A. Karapetrova, Ahmet Uysal, Pulak Dutta
    Abstract:

    Oscillatory surface-density profiles (layers) have previously been reported in several metallic Liquids, one Dielectric liquid, and in computer simulations of Dielectric Liquids. We have now seen surface layers in two other Dielectric Liquids, pentaphenyl trimethyl trisiloxane, and pentavinyl pentamethyl cyclopentasiloxane. These layers appear below T?285 K and T?130 K, respectively; both thresholds correspond to T/ Tc ?0.2 where Tc is the liquid-gas critical temperature. All metallic and Dielectric liquid surfaces previously studied are also consistent with the existence of this T/ Tc threshold, first indicated by the simulations of Chac?n [Phys. Rev. Lett. 87, 166101 (2001)]. The layer width parameters, determined using a distorted-crystal fitting model, follow common trends as functions of Tc for both metallic and Dielectric Liquids. ? 2010 The American Physical Society.

Sudeshna Chattopadhyay - One of the best experts on this subject based on the ideXlab platform.

  • Surface order in cold Liquids: X-ray reflectivity studies of Dielectric Liquids and comparison to liquid metals
    Physical Review B, 2010
    Co-Authors: Sudeshna Chattopadhyay, Benjamin Stripe, Evguenia A. Karapetrova, Ahmet Uysal, Steven N. Ehrlich, Pulak Dutta
    Abstract:

    Oscillatory surface-density profiles layers have previously been reported in several metallic Liquids, one Dielectric liquid, and in computer simulations of Dielectric Liquids. We have now seen surface layers in two other Dielectric Liquids, pentaphenyl trimethyl trisiloxane, and pentavinyl pentamethyl cyclopentasiloxane. These layers appear below T?285 K and T?130 K, respectively; both thresholds correspond to T/Tc?0.2 where Tc is the liquid-gas critical temperature. All metallic and Dielectric liquid surfaces previously studied are also consistent with the existence of this T/Tc threshold, first indicated by the simulations of Chacon et al. The layer width parameters, determined using a distorted-crystal fitting model, follow common trends as functions of Tc for both metallic and Dielectric Liquids.

  • Surface order in cold Liquids: X-ray reflectivity studies of Dielectric Liquids and comparison to liquid metals
    Physical Review B - Condensed Matter and Materials Physics, 2010
    Co-Authors: Sudeshna Chattopadhyay, Benjamin Stripe, Steven Ehrlich, Evguenia A. Karapetrova, Ahmet Uysal, Pulak Dutta
    Abstract:

    Oscillatory surface-density profiles (layers) have previously been reported in several metallic Liquids, one Dielectric liquid, and in computer simulations of Dielectric Liquids. We have now seen surface layers in two other Dielectric Liquids, pentaphenyl trimethyl trisiloxane, and pentavinyl pentamethyl cyclopentasiloxane. These layers appear below T?285 K and T?130 K, respectively; both thresholds correspond to T/ Tc ?0.2 where Tc is the liquid-gas critical temperature. All metallic and Dielectric liquid surfaces previously studied are also consistent with the existence of this T/ Tc threshold, first indicated by the simulations of Chac?n [Phys. Rev. Lett. 87, 166101 (2001)]. The layer width parameters, determined using a distorted-crystal fitting model, follow common trends as functions of Tc for both metallic and Dielectric Liquids. ? 2010 The American Physical Society.

Kasra Farain - One of the best experts on this subject based on the ideXlab platform.

  • universal rotation of nanowires in static uniform electric fields in viscous Dielectric Liquids
    Applied Physics Letters, 2018
    Co-Authors: Kasra Farain, Ali Esfandiar, A Z Moshfegh
    Abstract:

    The wide utilization of nanomanipulation as a promising approach in microorganisms, nanoelectromechanical systems, and assembly of nanostructures remarks the importance of nanostructures' motion in electric fields. Here, we study the rotational dynamics of metallic and non-metallic nanowires (NWs) in a static uniform electric field in viscous Dielectric Liquids. For metallic NWs, it has been theoretically shown that the electric field-induced rotation is practically independent of the geometrical dimensions and the electrical properties of NWs. Our experimental results for suspended silver (Ag) NWs in microscope oil are perfectly in agreement with this model. However, in the case of TiO2 NWs, as an example of non-metallic NWs, we surprisingly observe the exact same electromechanical torque as metallic Ag NWs under the same experimental conditions. This is mainly explained by NWs' high aspect-ratio which allows one to ignore the non-axial component of the electric field inside the NWs. Therefore, all high-aspect-ratio metallic Ag and non-metallic TiO2 NWs demonstrate an identical rotational speed in the same Dielectric liquid and electric field. This result can be used for the controllable alignment or synchronous rotation of an ensemble of different types of NWs for hybrid and advanced devices.The wide utilization of nanomanipulation as a promising approach in microorganisms, nanoelectromechanical systems, and assembly of nanostructures remarks the importance of nanostructures' motion in electric fields. Here, we study the rotational dynamics of metallic and non-metallic nanowires (NWs) in a static uniform electric field in viscous Dielectric Liquids. For metallic NWs, it has been theoretically shown that the electric field-induced rotation is practically independent of the geometrical dimensions and the electrical properties of NWs. Our experimental results for suspended silver (Ag) NWs in microscope oil are perfectly in agreement with this model. However, in the case of TiO2 NWs, as an example of non-metallic NWs, we surprisingly observe the exact same electromechanical torque as metallic Ag NWs under the same experimental conditions. This is mainly explained by NWs' high aspect-ratio which allows one to ignore the non-axial component of the electric field inside the NWs. Therefore, all high-...

A. Beroual - One of the best experts on this subject based on the ideXlab platform.

  • High frequency wideband permittivity measurements of Dielectric Liquids using a new stripline structure technique
    2019 International Conference on Advanced Electrical Engineering (ICAEE), 2019
    Co-Authors: M.a. Benaissa, A. Mokraoui, H. Moulai, A. Beroual
    Abstract:

    In this paper, we present a new approach for measuring the Dielectric Liquids relative permittivity over a wideband frequency in the microwave domain. This technique is based on the use of a stripline structure free of substrate as measuring probe. The relative Dielectric permittivity (Dielectric constant) of the Liquids under test is determined from the measured scattering parameters (S parameters) of the developed stripline structure using two different extraction methods where the need to calibrate the network analyzer was not necessary. The obtained results on a vegetable oil sample are in good agreement with results found by other works on the same frequency range using different techniques.

  • Parameters influencing the behavior of water droplets immersed in Dielectric Liquids submitted to electric stress
    2013 Annual Report Conference on Electrical Insulation and Dielectric Phenomena, 2013
    Co-Authors: A. Beroual
    Abstract:

    This paper is aimed at the analysis of the dynamics of water droplets immersed in Dielectric Liquids submitted to a uniform electric field up to breakdown. The influence of the sizes, position and concentration (number along the electrode axis) of water droplets with respect to the electrodes on their deformation and breakdown of oil gap is investigated. It is shown that the deformation can be symmetric or asymmetric depending on the surface charge density, the electrode gap, the positions, sizes and concentration of water droplets within this gap, the applied electric field and its application time. The conditions required to bridge the liquid gap are also discussed. It is also shown that even if the sizes of water droplets are insufficient to bridge the gap when elongated, local vaporization and discharges can be initiated at their poles and lead to breakdown.

  • electronic and gaseous processes in the prebreakdown phenomena of Dielectric Liquids
    Journal of Applied Physics, 1993
    Co-Authors: A. Beroual
    Abstract:

    The article shows experimentally the simultaneous influence of electronic scavenger additives and the hydrostatic pressure on the current and emitted light by streamers, especially in cyclohexane under negative polarity. This suggests that both electronic and gaseous mechanisms do not act singly in the prebreakdown phase of Dielectric Liquids. A relationship between the streamer current, the electrical charge, the velocity, and the propagation mode of streamers is discussed. Based on energy considerations, we establish a mathematical expression allowing us to evaluate the velocity of streamers and to explain the propagation modes. The streamer the current of which consists of discrete pulses moves by steps. The higher the number and/or the amplitude of the current pulses, the shorter the durations between these steps and the higher the average velocity of the streamers; its propagation tends to become continuous. That is the case of the slow streamers in the presence of electronic scavenger additives. On the other hand, the streamer becomes rapid then more energetic and the hydrostatic pressure necessary for its disappearance increases. That is why it is thought that both gaseous and electronic processes simultaneously act in the prebreakdown phase even if one of them is dominant in one case and the second in another.

Avram Barcohen - One of the best experts on this subject based on the ideXlab platform.

  • effusivity based correlation of surface property effects in pool boiling chf of Dielectric Liquids
    International Journal of Heat and Mass Transfer, 2003
    Co-Authors: Mehmet Arik, Avram Barcohen
    Abstract:

    Abstract Although the effects of fluid properties, pressure, and subcooling, as well as heater geometry, on the pool boiling critical heat flux, or CHF, are relatively well established, explanations for the surface property effects remain controversial. Proposed formulations, embodying the dependence of CHF on the product of the heater thermal effusivity and thickness are described and compared with available data. A composite correlation for pool boiling CHF, accounting for the conduction and hydrodynamic limits, as well as the effects of pressure, subcooling, and length, is proposed. This effusivity-based correlation is found to predict a broad range of pool boiling CHF data for Dielectric Liquids, for thermal effusivity values between 0.2 and 120, pressure from 100 to 450 kPa, and subcoolings from 0 to 75 K, with a standard deviation of 12.5%.