The effects of microwave cooking on the changes of physical properties, protein denaturation, microstructure and volatiles of yak meat were investigated. Various microwave power settings were used for cooking the yak longissimus meats, and SDS-PAGE, cooking loss, colour difference, shear force, microstructure and volatile flavour compounds of longissimus muscle were evaluated. Cooking losses (37.03-45.92%) and shear forces (257.20-315.57 N) in microwave heated meats were higher and lower, respectively, than these in boiled meats (p < .05). Cooking loss, a* values, and shear force significantly (p < .05) increased as the prolonged microwave cooking time, while L* value decreased (p < .05) and more muscle fibres fractured and contracted. High power (700 W; 100%) microwave cooked yak meat had higher L* values, but lower a* values and shear force than meats cooked at medium (560 W; 80%) or low (420 W; 60%) settings. Significant higher cooking loss and volatiles were found in medium power cooked meats compared to high and low power groups. The results suggested that microwave cooking could yield yak meat product with better texture and volatiles attributes but higher cooking loss and decolorization compared to conventional boiling cooking, and maybe an applicable processing method to obtain high quality yak meat products.

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Investigating the transient behaviour of liquid CO2 decompression is of great importance to ensure the safety of pipeline transportation in carbon capture and storage (CCS) technology. A computational fluid dynamics (CFD) decompression model based on the non-equilibrium phase transition and Span–Wagner equation of state (EoS) was developed to study the effects of actual flowing state within the pipeline on the transient behaviour of liquid CO2 decompression. Then, the CFD model was verified by comparing the simulated results to test data of a large-scale “shock tube” with an inner diameter of 146.36 mm. The results showed that the evaporation coefficient had a significant impact on the transition behaviour of CO2 decompression, while the condensation coefficient made no difference. When the evaporation coefficient was 15 s−1, the CFD-predicted results were in good agreement with the test results. Moreover, the effects of flow velocity on transient behaviour of liquid CO2 decompression were further investigated. It was found that the flow velocity affected the temperature drop of liquid CO2 during decompression, thereby affecting the phase transition of liquid CO2. In addition, the initial flow velocity also showed a significant influence on the transient behaviour of CO2 outside the pipe.