UNDERWATER SLIDING PROPERTIES: EFFECT OF SLIDER SHAPE AND SURFACE WETTABILITY

2016 ◽  
Vol 23 (05) ◽  
pp. 1650042 ◽  
Author(s):  
A. KIRVESLAHTI ◽  
K. MIELONEN ◽  
K. IKONEN ◽  
W. CUI ◽  
M. SUVANTO ◽  
...  
Keyword(s):  
Contact Angle ◽  
Surface Properties ◽  
Dynamic Test ◽  
Test Method ◽  
Surface Wettability ◽  
Flow Conditions ◽  
Modified Model ◽  
Variable Flow ◽  
Developed Surface ◽  
Surface Modified

A dynamic test method for the measurement of the underwater sliding properties of model boats has been developed. Surface-modified model boats were examined to assess how the surface wettability properties affect sliding. Along with the surface properties, the influence of the boat shape was considered. We studied various coatings in the contact angle range of 3–162[Formula: see text] with two model boat shapes. The hydrophobicity of the surfaces influenced the sliding speed of the model boat depending on the boat shape. The method is applicable to study sliding properties of model boats with different surfaces in variable flow conditions.

The Synthesis of Super-Hydrophobic Nano-Silica and its Effect to the Surface Wettability of Sandstone

2018 ◽  
Vol 917 ◽  
pp. 140-144
Author(s):  
Xiao Xiao Ni ◽  
Guang Cheng Jiang ◽  
Li Li Yang
Keyword(s):  
Contact Angle ◽  
Electron Microscope ◽  
Capillary Tube ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Spontaneous Imbibition ◽  
Surface Wettability ◽  
Glass Capillary ◽  
Water Contact ◽  
Surface Modified

In this paper, the researcher synthesis a super-hydrophobic nanosilica to alter the wettability of the sandstone surface from hydrophilic to super-hydrophobic. Fourier transform infrared (FTIR), Thermogravimetric analysis (TGA), Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) were used to test the characterization of the products, and the wettability were examined by contact angle measurement, glass capillary tube rise measurement and spontaneous imbibition tests. The results shows that the water contact angle is over 150°,the liquid level is down to-42mm and the spontaneous volume is only 0.025mL after the surface modified with super-hydrophobic nanosilica which means the surface wettability is altered to be super-hydrophobic.

scholarly journals Concept and Realization of a Novel Test Method Using a Dynamic Test Stand for Detecting Persons by Sensor Systems on Autonomous Agricultural Robotics

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2315
Author(s):  
Christian Meltebrink ◽  
Tom Ströer ◽  
Benjamin Wegmann ◽  
Cornelia Weltzien ◽  
Arno Ruckelshausen
Keyword(s):  
Environmental Conditions ◽  
Dynamic Test ◽  
Test Methods ◽  
Test Stand ◽  
Human Detection ◽  
Test Method ◽  
Sensor Systems ◽  
Functional Safety ◽  
Agricultural Robots ◽  
Agricultural Robotics

As an essential part for the development of autonomous agricultural robotics, the functional safety of autonomous agricultural machines is largely based on the functionality and robustness of non-contact sensor systems for human protection. This article presents a new step in the development of autonomous agricultural machine with a concept and the realization of a novel test method using a dynamic test stand on an agricultural farm in outdoor areas. With this test method, commercially available sensor systems are tested in a long-term test around the clock for 365 days a year and 24 h a day on a dynamic test stand in continuous outdoor use. A test over a longer period of time is needed to test as much as possible all occurring environmental conditions. This test is determined by the naturally occurring environmental conditions. This fact corresponds to the reality of unpredictable/determinable environmental conditions in the field and makes the test method and test stand so unique. The focus of the developed test methods is on creating own real environment detection areas (REDAs) for each sensor system, which can be used to compare and evaluate the autonomous human detection of the sensor systems for the functional safety of autonomous agricultural robots with a humanoid test target. Sensor manufacturers from industry and the automotive sector provide their sensor systems to have their sensors tested in cooperation with the TÜV.

Effect of Water Temperature, pH Value, and Film Thickness on the Wettability Behaviour of Copper Surfaces Coated with Copper Using EB-PVD Technique

2019 ◽  
Vol 60 ◽  
pp. 124-141 ◽  
Author(s):  
Naser Ali ◽  
Joao Amaral Teixeira ◽  
Abdulmajid Addali
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Film Thickness ◽  
Water Temperature ◽  
Ph Value ◽  
Surface Wettability ◽  
Copper Surfaces ◽  
Force Microscopy ◽  
Atomic Force ◽  
Static Contact

This research investigates the effect of surface roughness, water temperature, and pH value on the wettability behaviour of copper surfaces. An electron beam physical vapour deposition technique was used to fabricate 25, 50, and 75 nm thin films of copper on the surface of copper substrates. Surface topographical analysis, of the uncoated and coated samples, was performed using an atomic force microscopy device to observe the changes in surface microstructure. A goniometer device was then employed to examine the surface wettability of the samples by obtaining the static contact angle between the liquid and the attached surface using the sessile drops technique. Waters of pH 4, 7, and 9 were employed as the contact angle testing fluids at a set of fixed temperatures that ranged from 20°C to 60°C. It was found that increasing the deposited film thickness reduces the surface roughness of the as-prepared copper surfaces and thus causing the surface wettability to diverge from its initial hydrophobic nature towards the hydrophilic behaviour region. A similar divergence behaviour was seen with the rise in temperature of water of pH 4, and 9. In contrast, the water of pH 7, when tested on the uncoated surface, ceased to reach a contact angle below 90o. It is believed that the observed changes in surface wettability behaviour is directly linked to the liquid temperature, pH value, surface roughness, along with the Hofmeister effect between the water and the surface in contact.

Increasing Storage Modulus, Contact Angle and Surface Tension of Airway Mucus Increases Clearance by Simulated Cough Through a Model Trachea

2010 ◽  
Author(s):  
Anpalaki J. Ragavan ◽  
Cahit A. Evrensel ◽  
Peter Krumpe
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Storage Modulus ◽  
Surface Properties ◽  
Respiratory Diseases ◽  
Interactive Effects ◽  
Altered Surface ◽  
Human Trachea ◽  
Tension Increase ◽  
And Storage

Altered surface and viscoelastic material properties of mucus during respiratory diseases have a strong influence on its clearance by cilia and cough. Combined effects of the surface properties (contact angle and surface tension) and storage modulus with relatively unchanged viscosity on displacement of the simulated mucus aliquot during simulated cough through a model adult human trachea is investigated. For the mucus simulants used in this study contact angle and surface tension increase significantly as storage modulus increase while viscosity remains practically unchanged. Displacement of mucus simulant aliquots increased significantly with increasing storage modulus (and contact angle) at a given cough velocity in the range between 5 meters/second (m/s) and 30 m/s with duration 0.3 s. Results suggest that the interactive effects of elasticity and surface properties may help facilitate mucus displacement at low cough velocities.

Sign in / Sign up

Export Citation Format

Share Document