Quantitative evaluation method of smoke exhaust performance and application on exhaust volume optimization in tunnel fires under lateral centralized mode.

This study investigated the indicators in the quantitative method of evaluating the smoke exhaust performance, which provided a theoretical basis for the optimization of the smoke extraction system under the lateral centralized mode in tunnel fires. The criterion was proposed for plug-holing, and the theoretical models of smoke exhaust efficiency were established to distinguish whether the plug-holing occurs or not. The relationship between efficiency, effectiveness, and efficacy was analyzed from the perspective of smoke and heat exhaust. Meanwhile, this evaluation method was applied to the optimization of exhaust volume in a practical engineering through FDS numerical simulation. The results show that Ri is a vital basis for reflecting the movement form of smoke and the exhaust effect. The critical value of Ri is 1.09 when plug-holing occurs in a standard three-lane immersed tunnel, resulting in a significant reduction in the efficiency of smoke exhaust. The greater the exhaust volume of the exhaust fan, the greater the Ri value, the higher the total smoke and heat exhaust efficiency, and the better the exhaust effectiveness of smoke inlets without plug-holing. Under longitudinal ventilation, the optimal exhaust volume is 180 m3/s at 20 MW and 360 m3/s at 50 MW in the application case.

Reversed-Phase High-Performance Liquid Chromatography for the Quantification and Optimization for Extracting 10 Kinds of Carotenoids in Pepper (Capsicum annuum L.) Leaves.

Carotenoids are considered to be crucial elements in many fields and, furthermore, the significant factor in pepper leaves under low light and chilling temperature. However, little literature focused on the method to determinate and extract the contents of carotenoid compositions in pepper leaves. Therefore, a time-saving and highly sensitive reversed-phase high-performance liquid chromatography method for separation and quantification of 10 carotenoids was developed, and an optimized technological process for carotenoid composition extraction in pepper leaves was established for the first time. Our final method concluded that six xanthophylls eluted after about 9-26 min. In contrast, four carotenes showed higher retention times after nearly 28-40 min, which significantly shortened time and improved efficiency. Meanwhile, we suggested that 8 mL of 20% KOH-methanol solution should be added to perform saponification at 60 °C for 30 min. The ratio of solid-liquid was 1:8, and the ultrasound-assisted extraction time was 40 min.