scholarly journals Coral-like silicone nanofilament coatings with extremely low ice adhesion

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Davide Bottone ◽  
Valentina Donadei ◽  
Henna Niemelä ◽  
Heli Koivuluoto ◽  
Stefan Seeger

AbstractPassive icephobic surfaces can provide a cost and energy efficient solution to many icing problems that are currently handled with expensive active strategies. Water-repellent surface treatments are promising candidates for this goal, but commonly studied systems, such as superhydrophobic surfaces and Slippery Liquid Infused Porous Surfaces (SLIPS), still face challenges in the stability and durability of their properties in icing environments. In this work, environmental icing conditions are simulated using an Icing Wind Tunnel, and ice adhesion is evaluated with a Centrifugal Adhesion Test. We show that superhydrophobic coral-like Silicone Nanofilament (SNF) coatings exhibit extremely low ice adhesion, to the point of spontaneous ice detachment, and good durability against successive icing cycles. Moreover, SNFs-based SLIPS show stably low ice adhesion for the whole duration of the icing test. Stability of surface properties in a cold environment is further investigated with water wettability at sub-zero surface temperature, highlighting the effect of surface chemistry on superhydrophobicity under icing conditions.

Author(s):  
David Quéré ◽  
Mathilde Reyssat

Superhydrophobic materials recently attracted a lot of attention, owing to the potential practical applications of such surfaces—they literally repel water, which hardly sticks to them, bounces off after an impact and slips on them. In this short review, we describe how water repellency arises from the presence of hydrophobic microstructures at the solid surface. A drop deposited on such a substrate can float above the textures, mimicking at room temperature what happens on very hot plates; then, a vapour layer comes between the solid and the volatile liquid, as described long ago by Leidenfrost. We present several examples of superhydrophobic materials (either natural or synthetic), and stress more particularly the stability of the air cushion—the liquid could also penetrate the textures, inducing a very different wetting state, much more sticky, due to the possibility of pinning on the numerous defects. This description allows us to discuss (in quite a preliminary way) the optimal design to be given to a solid surface to make it robustly water repellent.


2009 ◽  
Vol 58 (5) ◽  
pp. 2137-2149 ◽  
Author(s):  
Y. Amara ◽  
L. Vido ◽  
M. Gabsi ◽  
E. Hoang ◽  
A. Hamid Ben Ahmed ◽  
...  

Wireless Sensor Networks (WSN) is a group of sensor devices, which are used to sense the surroundings. The network performance is still an issue in the WSN and an efficient protocol is introduced such as LEACH. To improve the stability, LEACH with fuzzy descriptors is used in preceding research. However the existing has drawback with effective group formation in heterogeneous WSN and also it is not achieved the Super Leader Node (SLH). To overcome the above mentioned issues, the proposed system enhances the approach which is used for increasing the energy consumption, packet delivery ratio, and bandwidth and network lifetime. The proposed paper contains three phases such as grouping formation, Leader Node (LN) selection, SLN selection with three main objectives:(i) to acquire Energy-Efficient Prediction Clustering Algorithm (EEPCA) in heterogeneous WSN for grouping formation (ii)To design Low Energy Adaptive Clustering Hierarchy- Expected Residual Energy (LEACH-ERE) protocol for LN selection.(iii)To optimize the SCH selection by Particle Swarm Optimization (PSO) based fuzzy approach. The clustering formation is done by Energy-Efficient Prediction Clustering Algorithm (EEPCA) in heterogeneous WSN. It is used to calculate the sensor nodes which have shortest distance between each node. The LEACH-ERE protocol was proposed to form a Leader Node (LN) and all the nodes has to communicate with sink through LN only. New SLN is elected based on distance from the sink and battery power of the node.


2012 ◽  
Vol 12 (8) ◽  
pp. 6340-6345 ◽  
Author(s):  
Asha Anish Madhavan ◽  
Sujith Kalluri ◽  
Anjali Paravannoor ◽  
Sivakumar Nagarajan ◽  
Kavasseri R. V. Subramanian ◽  
...  

2019 ◽  
pp. 310-318
Author(s):  
Christoph Schmahl ◽  
Michael Höck ◽  
Dirk Ressin ◽  
Mathias Kesseler

2010 ◽  
Vol 46 (33) ◽  
pp. 6120 ◽  
Author(s):  
Tianjiao Wu ◽  
Lingjuan Shen ◽  
Matthew Luebbers ◽  
Chunhua Hu ◽  
Qingmei Chen ◽  
...  

Author(s):  
S. A. Nassar ◽  
T. S. Sun

An experimental study is presented in order to investigate the effect of surface roughness on the torque-tension relationship in bolted assemblies. Three levels of surface roughness are considered for the fastener underhead and the joint surface; namely, low, medium, and high levels of surface roughness. The study is conducted for two joint materials, two fastener classes, and for coarse and fine threads. In this study, the torque-tension data is expressed in terms of the value of the nut factor as well as its scatter. The effect of the number of tightenings on surface roughness and on the torque-tension relationship is investigated as well. The surface roughness is measured before tightening, and after each loosening using a WYKO optical profiling system. An M12 fastener is used in this study. Both fine and coarse threads and fastener material Classes 8.8 and 10.9 for M12 fasteners are used in this study. The torque-tension data is analyzed for both steel and aluminum joints. The safety and reliability of bolted assemblies are mainly determined by the level and the stability of the clamp load provided by the initial tightening of the threaded fastener. The value of initial clamp load, which is achieved by a specific level of tightening torque, is highly sensitive to the friction torque components. This study provides an insight into the reliability of the existing engineering practices for estimating the clamp load level from the tightening torque. Hence, the findings of the study would help enhance the reliability and the safety of bolted assemblies, especially in critical applications.


Author(s):  
Sangjukta Devi ◽  
Niranjan Sahoo ◽  
P. Muthukumar

Abstract The existing biogas Conventional Burners (CBs) are less energy efficient and are designed for rich fuel combustion. Porous Media Burner (PMB), working on the principle of combustion in porous media offer several advantages including high thermal efficiency, low emissions, high power intensity, etc. In this work, a study on the effect of porous material on the thermal behaviour of a biogas operated PMB is presented. A state-of-the-art PMB working in the thermal load range of 5 to 10 kW has been developed, which can be used for both industrial and domestic purposes. It is a two section burner composed of a combustion zone and a preheat zone. Keeping the material of the preheat zone unchanged (Al2O3 ceramic), the burner is tested with two different materials in the combustion zone (SiC and ZrO2 foams). Experimental investigation has been done to analyze the stability criteria and study the temperature distribution in the PMB. This includes the identification of the stable operating limits (flashback and blow off) and measurement of temperature profiles in axial and radial direction. These assessments confirm that SiC is a better choice over ZrO2 for lean biogas combustion in PMB.


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