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.

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.

scholarly journals The Variation of Riverbed Material due to Tropical Storms in Shi-Wen River, Taiwan

2014 ◽  
Vol 2014 ◽  
pp. 1-12
Author(s):  
Chin-Ping Lin ◽  
Yu-Min Wang ◽  
Samkele S. Tfwala ◽  
Ching-Nuo Chen
Keyword(s):  
Grain Size ◽  
Geometric Mean ◽  
Size Variation ◽  
Annual Rainfall ◽  
Geometric Standard Deviation ◽  
Roughness Coefficient ◽  
Bed Form ◽  
Subsurface Material ◽  
Typhoon Season ◽  
Bed Material

Taiwan, because of its location, is a flood prone region and is characterised by typhoons which brings about two-thirds to three quarters of the annual rainfall amount. Consequently, enormous flows result in rivers and entrain some fractions of the grains that constitute the riverbed. Hence, the purpose of the study is to quantify the impacts of these enormous flows on the distribution of grain size in riverbeds. The characteristics of riverbed material prior to and after the typhoon season are compared in Shi-Wen River located at southern Taiwan. These include grain size variation, bimodality, and roughness coefficient. A decrease (65%) and increase (50%) in geometric mean size of grains were observed for subsurface and surface bed material, respectively. Geometric standard deviation decreased in all sites after typhoon. Subsurface material was bimodal prior to typhoons and polymodal after. For surface material, modal class is in the gravel class, while after typhoons it shifts towards cobble class. The reduction in geometric mean resulted to a decrease in roughness coefficient by up to 30%. Finally, the relationship of Shields and Froude numbers are studied and a change in the bed form to antidunes and transition form is observed, respectively.

scholarly journals Effect of reinforcement material on impact properties of epoxy

2017 ◽  
Vol 2 (3) ◽  
pp. 226-231
Author(s):  
Basim M. Fadhil ◽  
Payman Sahbah Ahmed ◽  
Ava Ali Kamal
Keyword(s):  
Carbon Fiber ◽  
Impact Test ◽  
Steel Fiber ◽  
Matrix Composites ◽  
Impact Machine ◽  
Impact Properties ◽  
Different Types ◽  
Experimental Works ◽  
Impact Characteristics ◽  
The Impact

Impact characteristics of Epoxy matrix composites is investigated by impact machine. Four different types of reinforcement are used in the experimental works: type one: 1.9wt% steel fiber, 1.9wt% carbon fiber,1.9 wt% carbon nanotube, 1.9 wt% woven carbon fiber.This work shows that reinforcing epoxy with (1.9 wt% of woven carbon fiber) improves the impact properties where energy, force and deformation values of impact test for this composite were 18.4J, 3580.59 N and 18 mm respectively while for epoxy were 2.927 J, 921.849 N and 18.413 mm respectively.

Material Grain Size Determines Relaxation-Time Distributions in Slow-Dynamics Experiments

2022 ◽  
Vol 17 (1) ◽  
Author(s):  
J. Kober ◽  
A.S. Gliozzi ◽  
M. Scalerandi ◽  
M. Tortello
Keyword(s):  
Grain Size ◽  
Relaxation Time ◽  
Slow Dynamics ◽  
Material Grain Size

scholarly journals Calibration of Circulating Tumor Cell’s Model in Narrow Flow

2019 ◽  
Vol 213 ◽  
pp. 02006
Author(s):  
Alžbeta Bohiniková ◽  
Katarína Bachratá
Keyword(s):  
Breast Cancer ◽  
Laboratory Experiment ◽  
Cancer Cell ◽  
Breast Cancer Cell ◽  
Flow Rate ◽  
Volumetric Flow Rate ◽  
Computational Time ◽  
Elastic Parameters ◽  
Entry Time ◽  
Different Types

In this article our objective was to calibrate model of Circulating Tumor Cell (CTC). Different types of cancer produce different types of CTCs. For research purposes, we chose to set up the model according to MCF7 breast cancer cell lines, due to the availability of data from laboratory experiments. First, to obtain working model we used mechanics of our already existing RBC model, taking into consideration the differences between RBC and CTC. Next step was to find values for the elastic parameters of the cell model. We have chosen laboratory experiment where the deformability of breast cancer cell passing through narrow microfluidic channel was examined. The channel has similar dimensions as blood capillaries to mimic the in vivo environment. In order to achieve similar behavior of the cell’s model and the real cell in the experiment we needed to set fluid flow according to experimental data. This was achieved by adjusting the fluid force that is dependent on the volumetric flow rate. Due to the long computational time of the simulation we devised a function between the entry time and the volumetric flow rate. Afterwards we also found dependencies between the changes in elastic parameters and entry time, and we were able to set the elastic parameters so they mimic the behaviour from the laboratory experiment. Further work lies in validating these results.

Computer Modeling of Ceramics Sintering: Effects of Inhomogeneity on Sintering Kinetics

2018 ◽  
Vol 281 ◽  
pp. 918-933
Author(s):  
Wen Dong Luo ◽  
Hai Peng Qiu ◽  
Jing Zhe Pan
Keyword(s):  
Surface Tension ◽  
Grain Size ◽  
Grain Boundary ◽  
Computational Model ◽  
Numerical Solution ◽  
Surface Diffusion ◽  
Triple Junction ◽  
Diffusion Mechanism ◽  
Sintering Kinetics ◽  
Effect Of Surface

In the sintering of ceramics, cracks are inevitably encountered after sintering. But very few studies have been presented in the literature for qualifying and quantifying effects of inhomogeneity on sintering kinetics. Therefore, a series of detailed sintering variables such as grain size, surface tension and diffusivity are chosen to study the effects of their inhomogeneity on sintering kinetics through a computational model calculated by computer.Furthermore, there are two main achievements in this computational model that first one is providing a numerical solution for the curvature at triple junction (pore tip) of microscopic particles, and second one is considering the effect of surface diffusion on first-stage sintering where diffusion mechanism is coupled by grain-boundary and surface diffusion.

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