The effects of tillage induced surface roughness, slope and discharge rate on soil detachment by concentrated flow: An experimental study

2021 ◽  
Author(s):  
Jiaqian Sun ◽  
Naichang Zhang ◽  
Mingxin Shi ◽  
Yanbin Zhai ◽  
Faqi Wu
2001 ◽  
Author(s):  
Jih-Hsing Tu ◽  
Fangang Tseng ◽  
Ching-Chang Chieng

Abstract Present study investigates the roughness effect on laminar gas flow for microchannels ranging from 40 to 600 μm with various roughness heights (40–82 nm) by systematical experiments. The micro-channels are manufactured by micro-machining technology and KOH anisotropic etching is employed to achieve various roughness patterns. Experimental results shows that higher product levels of Reynolds number (Reh) and friction factor (f) are obtained for microchannels of larger size and smaller relative roughness and friction factor f approaches to laminar flow theory value f0 for very smooth channel but the ratio of (f/f0) decreases as the surface roughness increases.


Author(s):  
Sayed A. Nassar ◽  
Ramanathan M. Ranganathan ◽  
Saravanan Ganeshmurthy ◽  
Gary C. Barber

This experimental study investigates the effect of tightening speed and coating on both the torque – tension relationship and wear pattern in threaded fastener applications. The fastener torque – tension relationship is highly sensitive to normal variations in the coefficients of friction between threads and between the turning head and the surface of the joint. Hence, the initial level of the joint clamp load and the overall integrity and reliability of a bolted assembly is significantly influenced by the friction coefficients. The effect of repeated tightening and loosening is also investigated using M12, Class 8.8, fasteners with and without zinc coating. The torque – tension relationship is examined in terms of the non-dimensional nut factor K. The wear pattern is examined by monitoring the changes in surface roughness using a WYKO optical profiler and by using a LECO optical microscope. A Hitachi S-3200N Scanning Electron Microscope (SEM) is used to examine the contact surfaces, under the fastener head, after each tightening/loosening cycle. Experimental data on the effect of variables and the tightening speed, fastener coating and repeated tightening on the nut factor are presented and analyzed for M8 and M12, class 8.8, fasteners.


2018 ◽  
Vol 661 ◽  
pp. 7-17 ◽  
Author(s):  
Moojoong Kim ◽  
Gwantaek Kim ◽  
Jaisuk Yoo ◽  
Dong-Kwon Kim ◽  
Hyunjung Kim

Author(s):  
Tarak Nath De ◽  
Bikramjit Podder ◽  
Nirmal Baran Hui ◽  
Chandan Mondal

Procedia CIRP ◽  
2020 ◽  
Vol 89 ◽  
pp. 277-281
Author(s):  
Yun Huang ◽  
Yuan Wu ◽  
Yi He ◽  
Quanzhong Zhao ◽  
Guijian Xiao ◽  
...  

2010 ◽  
Vol 426-427 ◽  
pp. 658-663 ◽  
Author(s):  
Min Kang ◽  
X.Q. Fu ◽  
Yong Yang

In order to machine revolving workpieces which are made of difficult-to-cut materials or have low rigidity, the technology of Numerical Controlled Electrochemical Turning (NC-ECT) was put forward and the preliminary experimental study was presented in this paper. To carry out the study, an experimental setup was developed, and a new special kind of inner-spraying cathode with single linear edge was designed according to the process of machining cylindrical surface and the requirement of stable electrolyte flow field. First, the NC-ECT method was simply described. Then, considering the structure of the cathode and the machining process, the method for calculating the material removed depth per revolution in machining the cylindrical surface was given. Finally, the experiments of machining the cylindrical surface were carried out. Experiments showed: 1) The calculated material removed depth per revolution is well consistent with the actual value of the machining process, which decreases with the increase of the rotational speed of the workpiece and increases almost linearly with the increase of the working voltage; 2) The surface roughness decreases with the increase of the rotational speed of the workpiece and the working voltage; 3) The working current in the machining process trend to stable after several revolutions.


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