Experimental study on flow characteristics of jet ventilation in crossflow in confined mine spaces.

The increasing depth of mine excavation presents greater challenges in mine ventilation and in managing cooling energy consumption. Therefore, there is an urgent need for comprehensive research on jet ventilation influenced by low-speed crossflows. This study investigated the impact of flow velocity ratios (R) and jet exit diameters (d) on flow-field distribution and flow characteristics through velocity measurements and smoke flow visualization experiments. The results of the study revealed two distinct types of air lakes formed by jet ventilation in crossflow (JVIC), with one being wall-attached and the other suspended. Notably, a significant secondary flow phenomenon was observed in the near-field near the upper wall. Additionally, the deflection angle (θj) of JVIC decreases as R and d/D increase, leading to the formation and movement of a semi-confined point (SP) and a confined point (CP) in the -x direction. Moreover, the wall confinement effect diminishes the jet's diffusion and deflection ability in the -z direction, leading to increased penetration in the x direction. Before the formation of the SP, the deflection section of the jet lengthens, followed by a rapid shortening upon its formation. Finally, the study further developed empirical equations for the jet axial trajectory and diffusion width.

Study on thermal health and its safety management mode for the working environment.

Thermal health concerns have gained significant attention due to the heightened health risks faced by workers who are exposed to extreme thermal environments for prolonged periods. To ensure the occupational health and safety of such workers, and to enhance work efficiency, it is imperative to examine the characteristics of thermal health in the working environment. This study proposes three key elements of thermal health in the working environment, namely thermal health states, absence of heat-related illnesses, and heat adaptability, which can be used to develop a safety management framework for thermal health. By exploring the interconnections between these elements, the study summarizes their features and outlines the necessary precautions to safeguard them. The PDCA (plan/do/check/action) cycle management mode is utilized as a framework, with the three components of thermal health forming the core, to establish a safety management mode for thermal health. To ensure that employees work in a safe, healthy, comfortable, and productive environment, the assessment and control objectives of the thermal environment are regularly revised through the use of labor protection technology and thermal environment control technology. This paper presents a PDCA cycle safety management mode based on the characteristics of thermal health, which offers novel insights and approaches for assessing and managing workers' thermal health.

Improvement of Al2O3 on the multi-pollutant control performance of NOx and chlorobenzene in vanadia-based catalysts.

We compared the influences of Al2O3 and SiO2 on a traditional V2O5-MoO3/TiO2 for the simultaneous removal of NOx and chlorobenzene (CB). The Al2O3 doping catalyst considerably broadens the active temperature window with higher NOx reduction and CB oxidation efficiencies than the SiO2 doping one and the V2O5-MoO3/TiO2. Furthermore, its resistance to SO2 was preserved and the quantities of polychlorinated byproducts also decreased. The increase in activity at low temperatures could be due to the promotion of vanadia reducibility via interactions between V2O5 and Al2O3. Moreover, the high temperature activity could be due to the additional surface acidities provided by Al2O3, in which the Lewis acid sites played the predominant role in both NH3 adsorptions and CB de-chlorination compared to the Brønsted acid sites. Finally, we proposed that Al2O3 is an effective addition for vanadia-based catalyst in NOx and CB simultaneous removal from stationary sources.