Anti-frost coatings containing carbon nanotube composite with reliable thermal cyclic property

2014 ◽  
Vol 2 (29) ◽  
pp. 11465-11471 ◽  
Author(s):  
Yoonchul Sohn ◽  
Dongouk Kim ◽  
Sangeui Lee ◽  
Mingming Yin ◽  
Jae Yong Song ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Stress Relaxation ◽  
Thermal Cycling ◽  
Mechanical Degradation ◽  
Superhydrophobic Coatings ◽  
Cyclic Property ◽  
Carbon Nanotube Composite

After repeated thermal cycling, MWNT–silicone superhydrophobic coatings retain their superhydrophobic nature with no mechanical degradation through a large amount of stress relaxation.

Stress relaxation behavior of annealed aluminum-carbon nanotube composite

2018 ◽  
Vol 25 (5) ◽  
pp. 1015-1019 ◽  
Author(s):  
Muhammad Mansoor ◽  
Muhammad Shahid
Keyword(s):  
Carbon Nanotube ◽  
Stress Relaxation ◽  
Pure Aluminum ◽  
Aluminum Matrix ◽  
Multiwall Carbon Nanotubes ◽  
Relaxation Behavior ◽  
Stress Relaxation Behavior ◽  
Thermally Activated ◽  
Carbon Nanotube Composite ◽  
Multiwall Carbon

AbstractThe mechanical properties and stress relaxation behavior of annealed aluminum-carbon nanotube composite were studied and compared with those of pure aluminum. The composite was prepared using an induction furnace, where 1.6 vol.% of multiwall carbon nanotubes were added in aluminum as strengthening material. It was found that the mechanical strength of the annealed composite was almost twice that of aluminum. The stress relaxation behavior of both materials was logarithmic in nature. However, the stress relaxation, hardening component, and intrinsic height of the thermally activated barrier were significantly influenced by the presence of nanotubes in the aluminum matrix. It was found that the stress relaxation rate of the composite was reduced (>30%) and the hardening component was increased (>100%) compared with that of aluminum. The calculated strengths of the thermally activated barriers for aluminum and the composite were 1.7 and 2.6 eV, respectively.

scholarly journals Supramolecular ionic polymer/carbon nanotube composite hydrogels with enhanced electromechanical performance

2020 ◽  
Vol 9 (1) ◽  
pp. 478-488 ◽  
Author(s):  
Yun-Fei Zhang ◽  
Fei-Peng Du ◽  
Ling Chen ◽  
Ka-Wai Yeung ◽  
Yuqing Dong ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Ion Mobility ◽  
Artificial Muscles ◽  
Ionic Polymer ◽  
Composite Hydrogels ◽  
The Matrix ◽  
Electromechanical Performance ◽  
Carbon Nanotube Composite ◽  
Robotic Devices

AbstractElectroactive hydrogels have received increasing attention due to the possibility of being used in biomimetics, such as for soft robotics and artificial muscles. However, the applications are hindered by the poor mechanical properties and slow response time. To address these issues, in this study, supramolecular ionic polymer–carbon nanotube (SIPC) composite hydrogels were fabricated via in situ free radical polymerization. The polymer matrix consisted of carbon nanotubes (CNTs), styrene sulfonic sodium (SSNa), β-cyclodextrin (β-CD)-grafted acrylamide, and ferrocene (Fc)-grafted acrylamide, with the incorporation of SSNa serving as the ionic source. On applying an external voltage, the ions accumulate on one side of the matrix, leading to localized swelling and bending of the structure. Therefore, a controllable and reversible actuation can be achieved by changing the applied voltage. The tensile strength of the SIPC was improved by over 300%, from 12 to 49 kPa, due to the reinforcement effect of the CNTs and the supramolecular host–guest interactions between the β-CD and Fc moieties. The inclusion of CNTs not only improved the tensile properties but also enhanced the ion mobility, which lead to a faster electromechanical response. The presented electro-responsive composite hydrogel shows a high potential for the development of robotic devices and soft smart components for sensing and actuating applications.

scholarly journals In-Situ Measurement of Power Loss for Crystalline Silicon Modules Undergoing Thermal Cycling and Mechanical Loading Stress Testing

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 72
Author(s):  
Sergiu Spataru ◽  
Peter Hacke ◽  
Dezso Sera
Keyword(s):  
Thermal Cycling ◽  
Power Loss ◽  
Stress Testing ◽  
Series Resistance ◽  
Short Circuit ◽  
In Situ Measurement ◽  
Mechanical Degradation ◽  
Model Parameters ◽  
The Impact

An in-situ method is proposed for monitoring and estimating the power degradation of mc-Si photovoltaic (PV) modules undergoing thermo-mechanical degradation tests that primarily manifest through cell cracking, such as mechanical load tests, thermal cycling and humidity freeze tests. The method is based on in-situ measurement of the module’s dark current-voltage (I-V) characteristic curve during the stress test, as well as initial and final module flash testing on a Sun simulator. The method uses superposition of the dark I-V curve with final flash test module short-circuit current to account for shunt and junction recombination losses, as well as series resistance estimation from the in-situ measured dark I-Vs and final flash test measurements. The method is developed based on mc-Si standard modules undergoing several stages of thermo-mechanical stress testing and degradation, for which we investigate the impact of the degradation on the modules light I-V curve parameters, and equivalent solar cell model parameters. Experimental validation of the method on the modules tested shows good agreement between the in-situ estimated power degradation and the flash test measured power loss of the modules, of up to 4.31 % error (RMSE), as the modules experience primarily junction defect recombination and increased series resistance losses. However, the application of the method will be limited for modules experiencing extensive photo-current degradation or delamination, which are not well reflected in the dark I-V characteristic of the PV module.

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