scholarly journals Effect of Grain Size and Surface Roughness on the Normal Coefficient of Restitution of Single Grains

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 814
Author(s):  
Chitta Sai Sandeep ◽  
Lina Luo ◽  
Kostas Senetakis
Keyword(s):  
Surface Roughness ◽  
Grain Size ◽  
Coefficient Of Restitution ◽  
Block Type ◽  
Flow Energy ◽  
Different Types ◽  
The Impact ◽  
Impact Experiments ◽  
Two Bodies ◽  
Effect Of Surface

The coefficient of restitution (COR) represents the fraction of pre-collision kinetic energy remained after the collision between two bodies. The COR parameter plays an important role in the discrete numerical analysis of granular flows or the design of protective barriers to reduce flow energy. This work investigated the COR for grain-block type impacts through comprehensive experiments using a custom-built impact loading apparatus. Glass balls of three different sizes were used as grains. The impact experiments were performed on three different types of materials as base blocks, namely brass, granite and rubber. Experiments on the brass block showed a decrease in COR values with increasing grain size. On the contrary, impacts on granite and rubber blocks showed an increase in COR values with increasing grain size. Additionally, the effect of surface roughness on the COR was investigated. It was revealed that the increase in surface roughness of either the grain or the block reduced the COR values due to the increased plastic deformations of surface asperities.

Effect of Surface Chemistry on Ruthenium Wet Etching

2021 ◽  
Vol 314 ◽  
pp. 302-306
Author(s):  
Quoc Toan Le ◽  
E. Kesters ◽  
M. Doms ◽  
Efrain Altamirano Sánchez
Keyword(s):  
Surface Roughness ◽  
Photoelectron Spectroscopy ◽  
Etching Rate ◽  
Wet Etching ◽  
X Ray ◽  
Force Microscopy ◽  
Metal Free ◽  
Atomic Force ◽  
Different Types ◽  
Effect Of Surface

Different types of ALD Ru films, including as-deposited, annealed Ru, without and with a subsequent CMP step, were used for wet etching study. With respect to the as-deposited Ru, the etching rate of the annealed Ru film in metal-free chemical mixtures (pH = 7-9) was found to decrease substantially. X-ray photoelectron spectroscopy characterization indicated that this behavior could be explained by the presence of the formation of RuOx (x = 2,3) caused by the anneal. A short CMP step applied to the annealed Ru wafer removed the surface RuOx, at least partially, resulting in a significant increase of the etching rate. The change in surface roughness was quantified using atomic force microscopy.

Effect of surface roughness on substrate-tuned gold nanoparticle gap plasmon resonances

Nanoscale ◽  
2015 ◽  
Vol 7 (9) ◽  
pp. 4250-4255 ◽  
Author(s):  
Chatdanai Lumdee ◽  
Binfeng Yun ◽  
Pieter G. Kik
Keyword(s):  
Surface Roughness ◽  
Gold Nanoparticles ◽  
Gold Nanoparticle ◽  
Single Particle ◽  
Gold Films ◽  
Particle Scattering ◽  
Plasmon Resonances ◽  
Scattering Spectra ◽  
The Impact ◽  
Effect Of Surface

The impact of nanoscale surface roughness on substrate-tuned gold nanoparticle plasmon resonances is demonstrated by comparing single-particle scattering spectra with simulated scattering spectra of gold nanoparticles on gold films with realistic roughness.

scholarly journals Effect of Roughness on Discharge

2013 ◽  
Vol 4 (3) ◽  
pp. 29-33 ◽  
Author(s):  
T.W. Lau ◽  
N.R. Afshar
Keyword(s):  
Grain Size ◽  
Flow Rate ◽  
Roughness Coefficient ◽  
Coefficient Increase ◽  
Different Types ◽  
Channel Slope ◽  
Experimental Works ◽  
Bed Roughness ◽  
Material Grain Size ◽  
Effect Of Surface

These Water resource projects and hydraulic engineering works have been developing rapidly throughout the world, thus prediction of water roughness coefficient is becoming an importance criteria for the designs of hydraulic related structure like open channel, and dam structure. The purposes of this research are to determine the effect of roughness on discharge and study on the factors that affect roughness coefficient. The roughness coefficient for this study is expressed in terms of Manning’s n. Experimental works were carried out to study the effect of roughness by using flumes (8m x 0.3m x 0.4m) with different types of roughened bed such as 2mm grain size plate and 5mm grain size plate. The experiments were being tested with various flow rates for slope equal to 1:300, 1:600 and 1:900 to determine the effect of slope on roughness coefficient. The results of the experimental study were presented and shown that the effect of surface roughness, material grain size, channel slope, and Manning’s roughness coefficient on flow rate. For the range of conditions tested, the discharge was found to be decreased as roughness coefficient increase. From the experiments, it shows smoother surface is having lower roughness coefficient and less retarding effect on the water flow, higher flow rate is produced. As conclusion, flow rate and roughness coefficient were influenced by bed roughness and slope.

Effect of Surface Roughness of Pure Aluminium A1100 on the Cold Work Extrusion by Using Different Angles of Taper Die

2013 ◽  
Vol 594-595 ◽  
pp. 546-550 ◽  
Author(s):  
Mohd Jamir Mohd Ridzuan ◽  
Mohd Bin Sulaiman Hafis ◽  
K. Azduwin ◽  
A.R. Mohamed ◽  
S.N. Fitriah ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Cold Work ◽  
Testing Machine ◽  
Extrusion Process ◽  
Pure Aluminium ◽  
Bio Oil ◽  
Different Types ◽  
Materials Used ◽  
Taper Die ◽  
Effect Of Surface

The study presented in this paper is focused on the effect of surfaces roughness of pure aluminium A1100 on the cold work extrusion process by three different angles of taper die. Different angles of taper die will affect the surface roughness of the workpiece. To protect the surface and to reduce friction, lubricants are often used in extrusion process [1]. Different lubricants may have different optimum taper die angle that are suitable to be applied. Two types of materials used in this experiment are steel SKD 11 for taper die and aluminium A1100 for workpiece and different angles applied are 30o, 45o, and 60o. Moreover, with respect to each angle, three different types of lubricants were used which are Daphne Draw S Series, Palm Olein, and EFB bio oil. The Universal Testing Machine and Surface Roughness Tester were used in this experiment. The result obtained from the experiment shows that at 30o of taper die angle were producing the smooth product surfaces for each lubricant and Daphne Draw S Series could reduce the surface roughness compared to other lubricant test.

scholarly journals Influence of Surface Roughness on the Cavitation Wear of P265GH and X2CrNi18-9 Steel Cavitation Generators

2018 ◽  
Vol 20 (3) ◽  
pp. 48-54
Author(s):  
Tomasz Linek ◽  
Tomasz Tanski ◽  
Wojciech Borek
Keyword(s):  
Surface Roughness ◽  
Grain Size ◽  
Mass Loss ◽  
Austenitic Steel ◽  
Pearlitic Steel ◽  
Nickel Steel ◽  
Flow Device ◽  
Cavitation Wear ◽  
304L Steel ◽  
Effect Of Surface

The aim of this paper was to determine the effect of surface roughness of cavitation generators made from two different materials: P265GH steel, with a ferritic-pearlitic structure, and X2CrNi18-9 (304L) steel with an austenitic structure on the mass loss and cavitation wear. Cavitation generators were tested in the conditions of cavitation wear environment continuously for 500 PMHs in a specially designed and constructed author's stream and flow device. Based on the carried out experiments was confirmed that the highest mass loss - 0.1752 g is seen for a sample of P265GH steel wet sanded with paper with the grain size of 1000. The smallest mass loss was recorded for the cavitation generator made of X2CrNi18-9 (304L) steel, sanded with sandpaper with the grain size of 2500. Certainly, the smallest number of cavitation wear effects was found for a cavitation generator made of austenitic steel X2CrNi18-9 (304L). Few places were identified based on macroscopic photographs, especially near the edges of the straight-through openings, but their number was much smaller than for the ferritic-pearlitic steel, which is associated most of all with the properties of austenitic chromium - nickel steel.

Effect of Surface Roughness on Single Cryogen Droplet Spreading

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Jie Liu ◽  
Walfre Franco ◽  
Guillermo Aguilar
Keyword(s):  
Surface Roughness ◽  
Human Skin ◽  
Droplet Diameter ◽  
Skin Surface ◽  
Skin Layer ◽  
Droplet Spreading ◽  
Viscous Boundary Layer ◽  
Superficial Skin ◽  
The Impact ◽  
Effect Of Surface

Cryogen spray cooling is an auxiliary procedure to dermatologic laser surgery, which consists of precooling the superficial skin layer (epidermis) during laser irradiation of subsurface targets to avoid nonspecific epidermal thermal damage. While previous studies have investigated the interaction of cryogen sprays with microscopically smooth human skin models, it is important to recognize that real human skin surface is far from smooth. With the objective to provide physical insight into the interaction between cryogen sprays and human skin, we study the effect of surface roughness on the impact dynamics of single cryogen droplets falling on skin models of various roughnesses (0.5–70μm). We first develop a theoretical model to predict the maximum spread diameter (Dm) following droplet impingement based on a similarity approximation to the solution of a viscous boundary layer that incorporates friction as the major source of viscous dissipation on a rough surface. Then, we measure the droplet diameter, impact velocity, and Dm of cryogen droplets falling by gravity onto skin models. Experimental data prove that the proposed model predicts Dm with good accuracy, suggesting that the effects of surface roughness and friction on Dm are properly taken into account for the range of surface roughness studied herein.

scholarly journals Energy dissipation of a particle colliding on a flat surface

2021 ◽  
Vol 249 ◽  
pp. 06007
Author(s):  
Fabricio Éric Fernández ◽  
Marcelo Fabián Piva ◽  
Román Gustavo Martino ◽  
María Alejandra Aguirre
Keyword(s):  
Kinetic Energy ◽  
Degrees Of Freedom ◽  
Flat Surface ◽  
Coefficient Of Restitution ◽  
Normal Direction ◽  
Normal Velocity ◽  
Factors Affecting ◽  
Different Types ◽  
Before And After ◽  
The Impact

To gain an understanding of the factors affecting the interaction of one grain with its environment as it reaches equilibrium, we study a particle bouncing off a flat surface. The bouncing of the particle leads to dissipation that is usually characterized with t, the coefficient of restitution, defined as the ratio between the velocity component that is normal to the contact surface just before impact (Vn) and the same component, but immediately after the collision (Vn’), i.e. related to a kinetic energy corresponding to motion in the normal direction. We will show how d is affected by energy stored in other degrees of freedom and transferred to kinetic energy that leads to an increase in normal velocity after the impact Vn’, and therefore to, ɛ >1. For this purpose, the evolution of potential, translational kinetic energy and rotational kinetic energy is analysed during the whole relaxation process and just before and after each collision for two different types of particle, a disk and a faceted particle.

scholarly journals Effect of Surface Roughness during Peristaltic Movement in a Nonuniform Channel

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
R. Shukla ◽  
S. S. Bhatt ◽  
A. Medhavi ◽  
R. Kumar
Keyword(s):  
Surface Roughness ◽  
Newtonian Fluid ◽  
Biological Fluids ◽  
Current Model ◽  
Roughness Parameter ◽  
Pressure Rise ◽  
Complete Agreement ◽  
Major Mode ◽  
The Impact ◽  
Effect Of Surface

In this study, the effect of the roughness parameter during the peristaltic transport of a Newtonian fluid in a nonuniform channel has been explored. The motivation of this study comes from various research studies in the area of life sciences and engineering, which reveal that the wall of living beings’ arteries and all other surfaces have roughness to some extent. As peristalsis is a major mode of transporting biological fluids in various organs, the effect of surface roughness during peristaltic flow becomes very significant. The problem of peristaltic motion of a Newtonian fluid through a rough nonuniform channel having sinusoidal-shaped roughness has been investigated in the current work. To analyze the flow, analytic formulation of pressure rise, friction force, velocity, and pressure gradient has been carried out under the low Reynolds number and long-wavelength approximation. Results obtained for zero surface roughness from the current model are in complete agreement with previous studies available in the literature that have been carried out without considering the surface roughness of the wall. Numerical outcomes for the properties mentioned above have been plotted for analyzing the impact of roughness on the physical and flow parameters.

The impact of landscape metrics on the grain size effect when analyzing different types of patches: A case study of Wuxi City

2016 ◽  
Vol 36 (9) ◽  
Author(s):  
吴未 WU Wei ◽  
许丽萍 XU Liping ◽  
张敏 ZHANG Min ◽  
欧名豪 OU Minghao ◽  
符海月 FU Haiyue
Keyword(s):  
Grain Size ◽  
Size Effect ◽  
Landscape Metrics ◽  
Grain Size Effect ◽  
Different Types ◽  
Wuxi City ◽  
The Impact

Strength of Ductile Adhesive Butt Joint Bonded with Dissimilar Adherents: Effect of Surface Roughness

2014 ◽  
Vol 554 ◽  
pp. 366-370 ◽  
Author(s):  
Nurul Atikah ◽  
Mohd Afendi ◽  
Siti Hirmaliza ◽  
Mohd Shukry Abdul Majid ◽  
Nurul Amira ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Static Loading ◽  
Testing Machine ◽  
Butt Joint ◽  
Butt Joints ◽  
Universal Testing ◽  
Different Types ◽  
Relationship Of ◽  
The Relationship ◽  
Effect Of Surface

The purpose of this project is to study the influence of the macroscopic state of surface roughness of the dissimilar adherent on the strength of adhesive joint. In this project, several types of sandpaper were used to produce different surface roughness of stainless steel and aluminium alloy adherents. All bonding surfaces were polished with different types of sandpaper. Butt joints of dissimilar adherent specimen were produced using a ductile adhesive (i.e. Araldite®Standard) with same bond thickness. The specimens were tested under static loading condition using universal testing machine (UTM) to investigate the relationship of the surface roughness and bond strength.

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