Cold storage systems release huge amount of condensation heat into the ambient leading to severe environmental pollution and significant energy waste. On the other hand, research into phase change materials appropriate to heat recovery in cold storages has not yet been well reported. The paper presented a dedicated study into a novel phase change composite material appropriate to this kind of application, which has relatively larger latent heat and thermal conductivity, and appropriate phase change temperature (i.e. 80 o C). Taking Carnauba Wax (CW) as the Phase Change Material (PCM) and the highly thermal conductive porous expanded graphite (EG) as the additive, a composite was thus developed at the mass ratio of 10:1 that was recognized as the optimal mixing rate. Thermal & physical properties and interior structure of the composite were then investigated by using the scanning electron microscope (SEM), thermal constants analyzer (Hot Disk), differential scanning calorimeter (DSC), and Fourier transform infrared spectrometer (FT-IR). Furthermore, experiments on the melting & solidification and the accelerated cooling & heating cycling were also undertaken. It is found that at the optimal mass ratio, temperatures of the CW/EG composite in the melting and solidification processes were 81.98 o C and 80.43 o C respectively, while the corresponding latent heats were 150.9J/g and 142.6J/g. During both processes, the CW could retain its original vermiform structure after being completely adsorbed by the EG. Compared to the CW alone, the melting and solidification timings of the CW/EG composite were reduced by 81.7% and 55.3% respectively; while its thermal conductivity became 17.4 times higher. After undertaking around 1000 runs of accelerated cooling & heating cycling, the endothermic/exothermic phase change temperatures of the CW and CW/EG composite were increased by only 0.42%/0.42% and 0.23%/0.27% respectively; while their endothermic/exothermic latent heats were reduced by 4.96%/4.78% and 2.05%/3.

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Quality sleep is vital for physical and mental health. No matter whether sleep problems are a consequence of or contributory factor to mental disorders, people with psychosis often suffer from severe sleep disturbances. Previous research has shown that acute sleep deprivation (SD) can cause transient brain dysfunction and lead to various cognitive impairments in healthy individuals. However, the relationship between sleep disturbance and bistable perception remains unclear. Here, we investigated whether the bistable perception could be affected by SD and elucidated the functional brain changes accompanying SD effects on bistable perception using functional magnetic resonance imaging. We found that the 28-h SD resulted in slower perceptual transitions in healthy individuals. The reduced perceptual transition was accompanied by the decreased activations in rivalry-related frontoparietal areas, including the right superior parietal lobule, right frontal eye field, and right temporoparietal junction. We speculated that SD might disrupt the normal function of these regions crucial for bistable perception, which mediated the slower rivalry-related perceptual transitions in behavior. Our findings revealed the neural changes underlying the abnormal bistable perception following the SD. It also suggested that SD might offer a new window to understand the neural mechanisms underlying the bistable perception.

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