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In this paper, we present an improved lattice Boltzmann model for fluid–fluid–solid (FFS) flows with a high viscosity ratio. The bounce-back particle model is combined with the Shan–Chen (SC) multicomponent model. We extend the bounce-back scheme based on velocity interpolation and a fresh-node initialization approach with second-order accuracy to moving particles within the framework of the multicomponent model. An improved virtual solid density model for wetting boundary conditions is employed to implement contact angles on curved boundaries. We examine the factors that lead to the violation of mass conservation, and an easy redistributing method is developed to fix the mass leakage issue. The combined multiphase particle model is able to simulate FFS flows with a high viscosity ratio of up to 1000 while preserving the total mass of the two fluids. The performance of the approach is tested by a variety of numerical experiments. The dynamic behaviors of moving contact lines on the curved boundary are validated by a droplet wetting on a solid particle. The model is then applied to simulate dynamic FFS problems, such as particle wetting at the fluid interface and particle motion through a fluid–fluid interface. According to the simulation results, the present model is capable of capturing the total force exerted on a particle by the fluid and the interface. However, the SC-type fluid–solid interaction force does not equal the capillary force in the present model. Finally, the self-assembly process of two floating particles on a liquid–liquid interface is investigated. [ABSTRACT FROM AUTHOR]

The obscure theory of passive subambient daytime radiative cooling (PSDRC) was deduced in a more understandable way using an arithmetic formula rather than integro-differential equations. Based on two boundary conditions of the equations, an innovative radiative cooler was successfully developed to qualitatively observe PSDRC phenomena and quantitatively characterize the cooling effect and cooling power of radiative cooling coatings (RC coatings). The remarkable subambient temperature reduction over 4.0 °C was successfully achieved in a completely open environment without minimizing the parasitic conduction and convection from the ambient. Prominent PSDRC phenomena could even be observed in such an open environment on very cloudy days, which generally compromise the RC. A much more prominent subambient cooling depression of 10.0 °C was observed when a wind shield was employed to minimize the convection. With suppression of convection, the subambient daytime cooling effect on cloudy days was even more noticeable than that occurred on clear sunny days. The subambient cooling effect was still very remarkable even on clear sunny days in the winter. The average cooling power measured on a clear sunny day was 154.8 ± 9.7 W/m2, corresponding to an average solar irradiance of 680 ± 90 W/m2 with a peak value of ∼820 W/m2. Both the subambient RC effect and the cooling power measured under real weather conditions using the radiative cooler agreed excellently with the theoretical prediction, sufficiently demonstrating the great innovation, validity, and effectiveness of the device. [ABSTRACT FROM AUTHOR]

Sound source localization in noisy and reverberant rooms using microphone arrays remains a challenging task, especially for small-sized arrays. Recent years have seen promising advances on deep learning assisted approaches by reformulating the sound localization problem as a classification one. A key to the deep learning-based approaches lies in extracting sound location features effectively in noisy and reverberant conditions. The popularly adopted features are based on the well-established generalized cross correlation phase transform (GCC-PHAT), which is known to be helpful in combating room reverberation. However, the GCC-PHAT features may not be applicable to small-sized arrays. This paper proposes a deep learning assisted sound localization method using a small-sized microphone array constructed by two orthogonal first-order differential microphone arrays. An improved feature extraction scheme based on sound intensity estimation is also proposed by decoupling the correlation between sound pressure and particle velocity components in the whitening weighting construction to enhance the robustness of the time-frequency bin-wise sound intensity features. Simulation and real-world experimental results show that the proposed deep learning assisted approach can achieve higher spatial resolution and is superior to its state-of-the-art counterparts using the GCC-PHAT or sound intensity features for small-sized arrays in noisy and reverberant environments. [ABSTRACT FROM AUTHOR]

The working principle of a continuous testing apparatus for the temperature reduction performance of cool coatings is presented in this work. The apparatus consists of infrared reflector type lamps, an adiabatic box, and a data acquisition system. It was calibrated with the different conventional reference panels. The tests for dynamic and steady state temperature reduction performances were illustrated with two cool coatings. Results obtained directly from the simultaneous measurement are in good agreement with those calculated from separate measurements, thus confirming this apparatus as a valuable experimental tool for research and development of cool coatings. [ABSTRACT FROM AUTHOR]