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A randomly distributed cavity model was constructed for 3D metal foam composite phase change materials (PCMs), and the multi-relaxation time lattice Boltzmann method was used to explore the cavity effects with different volume fractions, distribution locations, and thermal conductivity ratios of metal foam to PCM at the cavity scale. The results show that, with the increase of the cavity volume fraction, the heat transfer rate and latent heat storage capacity of composite PCMs would decrease. At a Fourier number of 0.7, compared to the case without cavity, the heat storage decreases respectively by 3.2%, 9.0%, and 13.0% for a cavity volume fraction of 2.4%, 7.6%, and 11.7%, respectively. The significant hindering effect on the melting process of composite PCMs occurs in the case of cavities with a volume fraction of 3% and concentrated near the high-temperature wall. The cavities act as an adiabatic layer, extending the complete melting time of composite PCMs by 6.1%. To weaken the cavity effect, the metal foam skeleton with a thermal conductivity ratio of more than 100 can be selected to improve its leading role in heat transfer. [ABSTRACT FROM AUTHOR]

Copyright of Advances in New & Renewable Energy is the property of Editorial Office of Advances in New & Renewable Energy and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Zinc fast roughing is the first process of zinc flotation, whose working conditions directly affect the performance of following cleaning and scavenging. The existing working condition recognition methods based on convolutional neural networks establish the relationship model between froth images and working conditions, and automatically mine the deep features associated with corresponding working conditions. These methods have acquired positive results, but ignore the dynamic temporal information of the froth videos at different sampling rates. Therefore, an improved slow-fast dual-flow network is proposed to identify zinc fast roughing working conditions based on froth videos. Firstly, the slow-fast dual-flow network is taken as the backbone network, and the P3D-A lightweight structure is introduced to reduce network parameters and improve the model reasoning efficiency. Then, Time Attention(TA),Channel Spatial Attention(CSA) and Spatial Time Together(STT) modules are integrated to preferably learn the spatial-temporal features of froth videos and promote the fusion of dual-flow networks. Finally, an Auxiliary Network (AN) is designed to reduce overfitting and improve the accuracy of condition identification. The industrial experiments show the effectiveness of the proposed method, in which the accuracy is 82. 54% and is improved by 11. 98% compared with the single slow-fast network. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of South China University of Technology (Natural Science Edition) is the property of South China University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Aeronautical Materials is the property of Editorial Board of Journal of Aeronautical Materials and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The metallic foam core of lightweight composite sandwich plates undergoes significant deformation along the thickness direction under shock loading, and hence the transverse normal and shear compressions of the core must be considered. A higher-order theory is used to analyze the transverse normal and shear strains of the core, whilst the Kirchhoff theory is used to analyze the thin composite facesheets because of their high-stiffness. The Hamilton's principle is used to obtain the equations governing the vibration performance of the sandwich plate. The extended Galerkin's method is used to solve the governing equations to obtain the vibration equation of the sandwich plate suitable for numerical analysis. The fourth-order Runge-Kutta method is employed to solve the transverse dynamic displacement of the sandwich plate within the elastic range. The inherent frequency of the sandwich plate is compared with the results of finite element method. Finally, the capacity to absorb energy of the sandwich plate is discussed by using the higher-order theory, and the influence of key system parameters is explored. The results show that the whole structural stiffness is affected by changing the ply angle of the facesheets and the thickness of the core, influencing the vibration characteristic of the sandwich composite; the structural vibration is weakened as energy is dissipated by the material damp; and the metal foam core absorbs most of the energy due to the transverse normal and shear compressions. [ABSTRACT FROM AUTHOR]

A metal foam/metal tube plastic deformation energy absorber is designed to reduce the high overload of projectile-borne equipment when a projectile penetrates into a target at high velocity. And the efficiency of the energy absorber to reduce the overload is studied by using finite element software LSDYNA. The overload-time curves of projectile-borne equipment are obtained during penetrating process, and compared with the curves obtained without any measures and with metal tube plastic deformation energy absorber. The results show that the metal foam/metal tube energy absorber can drastically reduce the overload of projectile-borne equipment at high velocity, especially, the efficiency of overload reduction and the working time is better than simple metal tube energy absorber. [ABSTRACT FROM AUTHOR]

By using self-designed gas explosion experimental pipe with the section of 30 cm x 30 cm, the authors carried out the experimental studies for the explosion suppression effects according to different parameters of metal wire mesh and foam ceramic materials and their combination. With the materials' characteristics, the function mechanism for the explosion suppression of the combination was analyzed. The results show that the performance of some parameters combined materials of wire mesh and the foam ceramic is better than that separate ones in the respect of pressure reduction and flame temperature and the damage of the explosion suppression materials is reduced obviously. The combined material can exert the advantages of original ones and avoid their disadvantages. The combined material can enhance the explosion suppression effects and reduce the damage of the materials. [ABSTRACT FROM AUTHOR]

Aluminum foam is a new type of material for shield of spacecrafts which bears fine characteristics when subjected to hypervelocity impact of space debris. A microstructure model of geometry for metallic foams was set up based on their manufacturing process and hypervelocity impact numerical simulations were conducted by self-programmed Smooth Particle Hydrodynamics. Six types of M-foam stuffed shields were calculated and their ballistic limits were compared with each other. The results indicated that shield performance of Al-foam stuffed shield was better than that of solid Al-plate stuffed shield with the same areal density if the Al-foam was stuffed at appropriate position. The analyses of characteristic parameters of debris cloud of different shields indicated that Al-foam had better shield performance on small-size debris. The microstructure of Al-foam could effectively spread the perpendicular momentum of debris cloud and significantly increase the proportion of material liquefaction and gasification in debris cloud through multi-shock. [ABSTRACT FROM AUTHOR]