Graphene-mediated suppression of Leidenfrost effect for droplets on an inclined surface

2022 ◽  
Vol 174 ◽  
pp. 107426
Author(s):  
Edmund Lim ◽  
Boon T. Ng ◽  
Yew M. Hung ◽  
Ming K. Tan
Keyword(s):  
Leidenfrost Effect ◽  
Inclined Surface

Free Convective Mass Transfer at Isosceles Triangular Surfaces of Varying Inclination

2003 ◽  
Vol 68 (11) ◽  
pp. 2080-2092 ◽  
Author(s):  
Martin Keppert ◽  
Josef Krýsa ◽  
Anthony A. Wragg
Keyword(s):  
Mass Transfer ◽  
Transfer Rate ◽  
Mass Transfer Rate ◽  
Mass Transfer Process ◽  
Sulfate Solution ◽  
Convective Mass Transfer ◽  
Varying Length ◽  
Inclined Surface ◽  
Vertical Case ◽  
Limiting Diffusion Current

The limiting diffusion current technique was used for investigation of free convective mass transfer at down-pointing up-facing isosceles triangular surfaces of varying length and inclination. As the mass transfer process, copper deposition from acidified copper(II) sulfate solution was used. It was found that the mass transfer rate increases with inclination from the vertical to the horizontal position and decreases with length of inclined surface. Correlation equations for 7 angles from 0 to 90° were found. The exponent in the ShL-RaL correlation ranged from 0.247 for the vertical case, indicating laminar flow, to 0.32 for inclinations of 60 to 90°, indicating mixed or turbulent flow. The general correlation ShL = 0.358(RaL sin θ)0.30 for the RaL sin θ range from 7 × 106 to 2 × 1011 and inclination range from 15 to 90° was obtained.

scholarly journals Centroid migration on an impacted granular slope due to asymmetric ejecta deposition and landsliding

2020 ◽  
Author(s):  
Tomomi Omura ◽  
Shinta Takizawa ◽  
Hiroaki Katsuragi
Keyword(s):  
Oblique Impact ◽  
Minor Axis ◽  
Sand Layer ◽  
Migration Distance ◽  
Fundamental Information ◽  
Fundamental Understanding ◽  
Dry Sand ◽  
Two Parameters ◽  
Inclined Surface ◽  
Crater Shape

Abstract For a fundamental understanding of terrain relaxation occurring on sloped surfaces of terrestrial bodies, we analyze the crater shape produced by an impact on an inclined granular (dry-sand) layer. Owing to asymmetric ejecta deposition followed by landsliding, the slope of the impacted inclined surface can be relaxed. Using the experimental results of a solid projectile impact on an inclined dry-sand layer, we measure the distance of centroid migration induced by asymmetric cratering. We find that the centroid migration distance xmig normalized to the crater minor-axis diameter Dcy can be expressed as a function of the initial inclination of the target tan θ, the effective friction coefficient μ, and two parameters K and c that characterize the asymmetric ejecta deposition and oblique impact effect: xmig/Dcy = Ktan θ/(1 − (tan θ/μ)2) + c, where K = 0.6, μ = 0.8, and c = −0.1 to 0.3. This result is consistent with a previous study that considered the effect of asymmetric ejecta deposition. The obtained results provide fundamental information for analyzing the degradation of sloped terrain on planetary surfaces, such as crater-shape degradation due to the accumulation of micro-impacts.

scholarly journals Control of Local Hardness Gradient of Metal Surface by Inclined Surface Treatment Using Ultrasonic Nanocrystal Surface Modification

2021 ◽  
Vol 8 (2) ◽  
pp. 533-546
Author(s):  
Yeong-Kwan Jo ◽  
Yeong-Wook Gil ◽  
Do-Sik Shim ◽  
Young-Sik Pyun ◽  
Sang-Hu Park
Keyword(s):  
Surface Modification ◽  
Surface Treatment ◽  
Metal Surface ◽  
Incident Angle ◽  
Surface Hardness ◽  
Parameter Study ◽  
Local Hardness ◽  
Practical Usefulness ◽  
Inclined Surface ◽  
Hardness Gradient

AbstractWe propose an effective method to control the local hardness and morphology of a metal surface by tilting the incident angle of a horn during ultrasonic nanocrystal surface modification (UNSM). In this study, surface treatment using UNSM was performed on an S45C specimen and a parameter study was conducted for optimization. The process parameters were the feeding rate, static load, striking force, and processing angle (Ф). In particular, the Ф was analyzed by tilting the horn by 0°, 10°, 20°, 30°, 40°, and 45° to understand its effect on surface hardness and changes in the morphology. From fundamental experiments, some important phenomena were observed, such as grain-microstructure changes along the processing and thickness directions. Furthermore, to verify the practical usefulness of this study, a flat and a hemispherical specimen of S45C material were treated using UNSM with various values of Ф. A significant change in hardness (an increase from 2–45%) and a gradual hardness gradient on the tested specimens could be easily realized by the proposed method. Therefore, we believe that the method is effective for controlling the mechanical hardness of a metal surface.

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