scholarly journals Wetting and recovery of nano-patterned surfaces beyond the classical picture

Nanoscale ◽  
2019 ◽  
Vol 11 (44) ◽  
pp. 21458-21470 ◽  
Author(s):  
Sara Marchio ◽  
Simone Meloni ◽  
Alberto Giacomello ◽  
Carlo Massimo Casciola
Keyword(s):  
Experimental Results ◽  
Patterned Surfaces ◽  
Hydrophobic Surfaces ◽  
Inertia Effects ◽  
Classical Picture

Here we investigate the wetting and dewetting of textured hydrophobic surfaces including inertia effects, which have been neglected in previous studies but are necessary to match experimental results.

Measurements of Leakage in Mechanical Face Seals

1969 ◽  
Vol 91 (4) ◽  
pp. 687-694 ◽  
Author(s):  
J. A. Findlay
Keyword(s):  
Experimental Results ◽  
Inertia Effects ◽  
Face Seals ◽  
Two Fluid ◽  
Theoretical Results

The characteristics of mechanical face seals operating with hydrodynamic films were studied experimentally and analytically. Experimental and theoretical results are given showing the effects of gas cavities in the film and inward pumping. Photographs taken through the transparent test seal show the characteristics of the gas cavities. Experimental results are also given for the two fluid case, i.e., where the seal separates two different fluids; and for the case where inertia effects are important.

scholarly journals Anisotropic electro-osmotic flow over super-hydrophobic surfaces

2010 ◽  
Vol 644 ◽  
pp. 245-255 ◽  
Author(s):  
SUPREET S. BAHGA ◽  
OLGA I. VINOGRADOVA ◽  
MARTIN Z. BAZANT
Keyword(s):  
Double Layers ◽  
Patterned Surfaces ◽  
Hydrophobic Surfaces ◽  
Electrokinetic Phenomena ◽  
Flat Surfaces ◽  
Mobility Tensor ◽  
Special Cases ◽  
Hydrodynamic Slip ◽  
Effective Slip ◽  
Trapped Gas

Patterned surfaces with large effective slip lengths, such as super-hydrophobic surfaces containing trapped gas bubbles, have the potential to greatly enhance electrokinetic phenomena. Existing theories assume either homogeneous flat surfaces or patterned surfaces with thin double layers (compared with the texture correlation length) and thus predict simple surface-averaged, isotropic flows (independent of orientation). By analysing electro-osmotic flows over striped slip-stick surfaces with arbitrary double-layer thickness, we show that surface anisotropy generally leads to a tensorial electro-osmotic mobility and subtle, nonlinear averaging of surface properties. Interestingly, the electro-osmotic mobility tensor is not simply related to the hydrodynamic slip tensor, except in special cases. Our results imply that significantly enhanced electro-osmotic flows over super-hydrophobic surfaces are possible, but only with charged liquid–gas interfaces.

The Simultaneous Effects of Thermal and Inertia in Curved Circular Squeeze Films

1980 ◽  
Vol 102 (4) ◽  
pp. 501-504 ◽  
Author(s):  
R. S. Gupta ◽  
V. K. Kapur
Keyword(s):  
Pressure Drop ◽  
Close Agreement ◽  
Present Theory ◽  
Numerical Results ◽  
Experimental Results ◽  
Squeeze Film ◽  
Flat Plates ◽  
Inertia Effects

Interaction of thermal and inertia effects on squeeze film action for curved plates have been investigated. To illustrate the importance of the study, the numerical results obtained from the present theory for pressure drop for flat plates have been compared with the experimental results of Tichy and Winer which are in close agreement at 70°F. The behavior of the curvature of the film has also been illustrated in figures for load correction parameter.

Longitudinal Impact of Cylindrical Shells With Discontinuous Cross-Sectional Area

1972 ◽  
Vol 39 (4) ◽  
pp. 1005-1010 ◽  
Author(s):  
R. W. Mortimer ◽  
J. L. Rose ◽  
A. Blum
Keyword(s):  
Cylindrical Shells ◽  
Cross Sectional Area ◽  
Experimental Results ◽  
Longitudinal Impact ◽  
Sectional Area ◽  
Governing Equations ◽  
Cross Sectional ◽  
Inertia Effects ◽  
Stress Ratios ◽  
Good Agreement

The reflections and transmissions of longitudinal strain pulses in cylindrical shells having cross-sectional area discontinuities are studied both analytically and experimentally. Three different theories were used to analyze this problem: the first, termed “bending” theory, includes the transverse shear, radial inertia, and rotary inertia effects; the second is based on a modified “membrane” theory; the last is derived from the “uniaxial” theory. Solutions were obtained by solving each of the three systems of governing equations by the method of characteristics. The longitudinal and circumferential incident, reflected, and transmitted strain pulses calculated from the bending and membrane theories are shown to be in good agreement with the experimental results, whereas the uniaxial comparisons are poor. In addition, the calculated reflected and transmitted stress ratios are in good agreement with the experimental results; the ratios obtained from the uniaxial theory are shown to be generally inadequate.

Inertia Effects on Compressible Squeeze Films

1995 ◽  
Vol 117 (1) ◽  
pp. 94-102 ◽  
Author(s):  
Jongmin Kang ◽  
Zhaoshun Xu ◽  
Adnan Akay
Keyword(s):  
Numerical Solutions ◽  
Fluid Layer ◽  
Phase Changes ◽  
Experimental Results ◽  
Squeeze Film ◽  
Fluid Inertia ◽  
Inertia Effects ◽  
Bearing Force ◽  
The Mean ◽  
Squeeze Number

In this paper, the combined effects of compressibility and fluid inertia in a squeeze film are considered. The governing equations are derived using an integral method for a one-dimensional case, initially considering a combination of Couette and Poiseuille Flows. Numerical and experimental results are obtained for the case of a pure squeeze film between flat circular disks. Influence of the film geometry was examined by considering a cavity on the surface of one of the disks. The numerical solutions are obtained by use of the Crank-Nicholson method with Lax modification. Comparison of the numerical results for pressure in the film with the experimental results show good agreement. The inertia of the fluid is found to significantly influence the pressure waveform in the film by altering the phase of the pressure developed in the film with respect to the oscillating disk. It is shown that these phase changes lead to “resonances” in the mean bearing force. The results also show that the mean bearing force can be superambient or subambient depending on the squeeze number. Both the damping and the bearing force show a “jump” at a critical squeeze number. Damping due to the fluid layer is shown to be amplitude-dependent.

Intermediate wetting state at nano/microstructured surfaces

Soft Matter ◽  
2020 ◽  
Vol 16 (14) ◽  
pp. 3514-3521 ◽  
Author(s):  
Gyoko Nagayama ◽  
Dejian Zhang
Keyword(s):  
Experimental Results ◽  
Hydrophobic Surfaces ◽  
Partial Wetting ◽  
Microstructured Surfaces ◽  
Wetting Model

A general partial wetting model to describe an intermediate wetting state is proposed in this study to explain the deviations between the experimental results and classical theoretical wetting models for hydrophobic surfaces.

Theoretical and Experimental Investigations of a Short 360° Journal Bearing in the Transition Superlaminar Regime

1974 ◽  
Vol 16 (5) ◽  
pp. 286-297 ◽  
Author(s):  
H. F. Black ◽  
M. H. Walton
Keyword(s):  
Effective Viscosity ◽  
Dynamic Behaviour ◽  
Journal Bearing ◽  
Experimental Results ◽  
Taylor Vortex ◽  
Experimental Investigations ◽  
Fluid Inertia ◽  
Approximate Representation ◽  
Inertia Effects ◽  
Dynamic Forcing

An empirical treatment is used to derive effective viscosity constants governing pressure-induced flows in Taylor Vortex regimes. The theory of static and linearized dynamic behaviour of a short journal is developed, including an approximate representation of fluid inertia effects. Theory is compared with experimental results of duty parameters, attitude loci and dynamic forcing due to rotation of an eccentric journal.

Diagnostics of Gold Laser Plasmas

1988 ◽  
Vol 102 ◽  
pp. 357-360
Author(s):  
J.C. Gauthier ◽  
J.P. Geindre ◽  
P. Monier ◽  
C. Chenais-Popovics ◽  
N. Tragin ◽  
...  
Keyword(s):  
Experimental Results ◽  
Pure Gold ◽  
Electronic Temperature ◽  
X Ray ◽  
Laser Plasmas ◽  
Collisional Radiative Model ◽  
Radiative Model

AbstractIn order to achieve a nickel-like X ray laser scheme we need a tool to determine the parameters which characterise the high-Z plasma. The aim of this work is to study gold laser plasmas and to compare experimental results to a collisional-radiative model which describes nickel-like ions. The electronic temperature and density are measured by the emission of an aluminium tracer. They are compared to the predictions of the nickel-like model for pure gold. The results show that the density and temperature can be estimated in a pure gold plasma.

Observation of Phase Contrast Images in STEM and CTEM Modes by Using 100 kV Field Emission Electron Gun

1974 ◽  
Vol 32 ◽  
pp. 390-391
Author(s):  
Y. Harada ◽  
T. Goto ◽  
H. Koike ◽  
T. Someya
Keyword(s):  
Field Emission ◽  
Phase Contrast ◽  
Image Formation ◽  
Fresnel Diffraction ◽  
Experimental Results ◽  
Electron Gun ◽  
Scanning Microscopy ◽  
Emission Electron ◽  
Lattice Images

Since phase contrasts of STEM images, that is, Fresnel diffraction fringes or lattice images, manifest themselves in field emission scanning microscopy, the mechanism for image formation in the STEM mode has been investigated and compared with that in CTEM mode, resulting in the theory of reciprocity. It reveals that contrast in STEM images exhibits the same properties as contrast in CTEM images. However, it appears that the validity of the reciprocity theory, especially on the details of phase contrast, has not yet been fully proven by the experiments. In this work, we shall investigate the phase contrast images obtained in both the STEM and CTEM modes of a field emission microscope (100kV), and evaluate the validity of the reciprocity theory by comparing the experimental results.

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