Solar heat absorbing coating from multi-walled carbon nanotube composites with linear low-density polyethylene-coated copper sheet

2017 ◽  
Vol 36 (9) ◽  
pp. 714-721
Author(s):  
Samor Boonphan ◽  
Pisith Singjai

This study aims to investigate the effects of multi-walled carbon nanotubes (MWNTs)/linear low density polyethylene composite-coated copper sheets on an energy conversion efficiency of a solar water heating system. Volume percentages of 1, 3 and 5 MWNTs were ball-mill mixed with linear low density polyethylene before using a hot press method to coat the composites. A bonding layer between the composites and the copper sheets was intercalated using MWNTs/polyvinyl butyral composites. The strength of the bonding layer was tested using a shear tension test. Microstructures of the composites were observed by scanning electron microscopy. The energy conversion efficiency and solar absorptance of the solar heat absorbing coatings were measured by a home-made method and ultraviolet visible spectroscopy, respectively. The results showed that the efficiency and the absorptance increased by 40% and 0.95, respectively with the increasing volume percentages of MWNTs up to 5 vol.% in linear low density polyethylene.

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1135-1143
Author(s):  
Chao Jiang ◽  
Wencai Liu ◽  
Yun Song ◽  
Xinjun Wu

The EMAT (electromagnetic acoustic transducer) has been used to measure the thickness of the metallic plate in some industries recently. Comparing with the piezoelectric transducer, its low energy conversion efficiency due to the lift-off effect limits its further application. Based on the eddy current energy partition, the distances between the copper sheet and the coils are studied. In consideration of the influence of magnetic flux density, a principle about the energy conversion efficiency and the coils position is proposed. The optimal distances between the copper sheet and the coils under a certain lift-off are obtained through a series of simulation and experiment. The results offer a method for the EMAT structure design.


2013 ◽  
Vol 9 (S296) ◽  
pp. 358-359
Author(s):  
Xiao Zhang ◽  
Yang Chen ◽  
Hui Li ◽  
Xin Zhou

AbstractTycho is one of nearly a dozen Galactic supernova remnants which are suggested to emit hadronic γ-ray emission. Among them, however, it is the only one in which the hadronic emission is proposed to arise from the interaction with low-density ambient medium. Based on the multi-band observations, we suggest that Tycho is encountering dense cloud at the northeastern boundary. The γ-ray emissions can be explained by hadronic process with self-consistent parameters, such as a modest energy conversion efficiency. In this SNR-cloud association scenario, the distance can be estimated as ~2.5 kpc.


2021 ◽  
Author(s):  
Xianhao Zhao ◽  
Tianyu Tang ◽  
Quan Xie ◽  
like gao ◽  
Limin Lu ◽  
...  

The cesium lead halide perovskites are regarded as effective candidates for light-absorbing materials in solar cells, which have shown excellent performances in experiments such as promising energy conversion efficiency. In...


Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1537
Author(s):  
Luděk Hynčík ◽  
Petra Kochová ◽  
Jan Špička ◽  
Tomasz Bońkowski ◽  
Robert Cimrman ◽  
...  

Current industrial trends bring new challenges in energy absorbing systems. Polymer materials as the traditional packaging materials seem to be promising due to their low weight, structure, and production price. Based on the review, the linear low-density polyethylene (LLDPE) material was identified as the most promising material for absorbing impact energy. The current paper addresses the identification of the material parameters and the development of a constitutive material model to be used in future designs by virtual prototyping. The paper deals with the experimental measurement of the stress-strain relations of linear low-density polyethylene under static and dynamic loading. The quasi-static measurement was realized in two perpendicular principal directions and was supplemented by a test measurement in the 45° direction, i.e., exactly between the principal directions. The quasi-static stress-strain curves were analyzed as an initial step for dynamic strain rate-dependent material behavior. The dynamic response was tested in a drop tower using a spherical impactor hitting a flat material multi-layered specimen at two different energy levels. The strain rate-dependent material model was identified by optimizing the static material response obtained in the dynamic experiments. The material model was validated by the virtual reconstruction of the experiments and by comparing the numerical results to the experimental ones.


2017 ◽  
Vol 46 (18) ◽  
pp. 5872-5879 ◽  
Author(s):  
Mandvi Saxena ◽  
Tanmoy Maiti

Increasing electrical conductivity in oxides, which are inherently insulators, can be a potential route in developing oxide-based thermoelectric power generators with higher energy conversion efficiency.


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