Screening and constructing low cost, highly efficient and robust electrocatalysts with high oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) activity is crucial for rechargeable metal–air batteries. Metal phosphides coupled with heteroatom doped carbon are promising candidates for oxygen electrodes. In this work, we demonstrate a facile strategy to synthesize cobalt phosphide anchored heteroatom (N,P) co-doped porous carbon (CoP/NP-HPC) through a one-step pyrolysis of bimetal–organic frameworks with a simple in situ phosphorization process. In alkaline solution, the obtained CoP/NP-HPC catalyst exhibits high bifunctional catalytic activity toward ORR and OER, comparable to commercial 20% Pt/C or even better, which is attributed to the synergistic effect between the CoP active sites and N,P co-doped carbon, and the porous framework as a channel benefiting the diffusion of reaction species. Notably, a rechargeable Zn–air battery with CoP/NP-HPC as the cathode electrocatalyst delivers a high power density of 186 mW cm⁻², as well as good long-term charge/discharge cyclic stability, outperforming 20% Pt/C. The hybrid catalyst of CoP anchored heteroatom doped carbon provides a possibility and an opportunity to promote the development of low-cost and highly efficient bifunctional catalysts for ORR and OER in applications of metal–air batteries.

Cooling vests incorporated with phase change materials (PCMs) add extra insulation and restrict sweat evaporation. It is still unclear how much cooling benefit they can provide. The aim of this study was to investigate the torso cooling of the PCM vests in two hot environments: hot humid (HH, 34°C, 75% relative humidity (RH)) and hot dry (HD, 34°C, 37% RH). A pre-wetted torso fabric skin was used to simulate torso sweating on a thermal manikin. Three cooling vests incorporated with three melting temperatures ( T_m) of PCMs were tested ( T_m = 21°C, T_m = 24°C and T_m = 28°C). They were worn under a military ensemble (total thermal insulation 1.60 clo; evaporative resistance 0.0516 kPaċm²/W), respectively. In a HH environment all the three cooling vests provided effective torso cooling; in a HD environment the cooling benefit was negative. In both environmental conditions, the evaporative cooling was greatly restricted by the cooling vests. The study indicated that when wearing the protective clothing with the relatively low evaporative resistance and when sweat production was high, the cooling vests were effective in a HH environment, but not in a HD environment.

The objective of the study is to establish a quantitative relationship between air gap sizes and clothing thermal performance. Using a three-dimensional human body scanner, the thicknesses and volumes of air gaps of 35 experimental shirts were measured. Relationships between the thermal insulations of clothing, measured on a thermal manikin, and air gap volumes were examined by regression analysis. Also, the regression model between clothing surface temperatures, measured by an infrared thermal camera, and air gap thicknesses was established. The results proved that the thermal insulation of experimental shirts increased with air gap sizes but began to decrease as a result of natural convection when the air gap thickness was higher than 1 cm or the air gap volume was greater than 6000 cm³. The 3D human body scanner can accurately measure air gaps under clothing, but it is expensive and is not available everywhere. A substitute method is to build a mathematical model for predicting air gap sizes. In this paper, regression models were established to estimate volumes and thicknesses of air gaps when the ease allowances of chest circumference and fabric properties were known. This study can be used to predict the thermal performance of clothing at the product’s design stage.

Relative humidity (RH) and air gap size are two characteristic indices of clothing microclimate. The current thermal protective performance (TPP) tests cannot evaluate protective performance of fabrics under a microclimate with high temperature and humidity. In this study, a newly modified TPP test apparatus was applied to investigate the effect of RH in a microclimate on heat transfer of fabrics exposed to flash fires. Air gap heights from 0 to 24 mm with increments of 3 mm were employed. Three microclimates with different RH were preconditioned respectively. The results indicate that the RH in a microclimate significantly improves thermal protection of fabric with various air gaps. Under 35% RH, the TPP obviously increases with the air gap up to 15 mm and then the increment becomes a little lower; under humidified conditions (65% or 95% RH), it becomes higher substantially with air gap height increasing until 12 mm, subsequently it decreases or increases alternatively if the size keeps increasing. The positive effect of air gap with small size on TPP of fabrics is enhanced due to the increase of the vapor in the air; however, the positive effect of air gap with large size is interfered by the RH. It is indicated that around 12–15 mm was a critical air gap size under 35% RH, while about 12 mm was a key air gap size for a damp microclimate with 65% or 95% RH.