J. M. Hao

Estimating mercury emissions from a zinc smelter in relation to China's mercury control policies.

Mercury concentrations of flue gas at inlet/outlet of the flue gas cleaning, electrostatic demister, reclaiming tower, acid plant, and mercury contents in zinc concentrate and by-products were measured in a hydrometallurgical zinc smelter. The removal efficiency of flue gas cleaning, electrostatic demister, mercury reclaiming and acid plant was about 17.4%, 30.3%, 87.9% and 97.4% respectively. Flue gas cleaning and electrostatic demister captured 11.7% and 25.3% of the mercury in the zinc concentrate, respectively. The mercury reclaiming tower captured 58.3% of the mercury in the zinc concentrate. About 4.2% of the mercury in the zinc concentrate was captured by the acid plant. Consequently, only 0.8% of the mercury in the zinc concentrate was emitted to the atmosphere. The atmospheric mercury emission factor was 0.5 g t(-1) of zinc produced for the tested smelter, indicating that this process offers the potential to effectively reduce mercury emissions from zinc smelting.

A data-driven approach for duration evaluation of accident impacts on urban intersection traffic flow

Accurate and rapid estimation and prediction of accident impacts are significant, as it assists road administration to alleviate traffic congestion and help the road users to make better travel decisions. In either case, information of how long an accident affects the traffic at nearby intersections is essential. Although there have been various approaches regarding prior-accident issues, only a few studies have been able to evaluate the impacts after an accident. With the emerging of new traffic sensor technologies, traffic data have exploded. This inspires us to rethink the accident impacts evaluation problem based more on intensive data. Accordingly, a practical data-driven method is proposed in this paper, whose functions are twofold: 1) to identify the flow characteristic of each intersection based on the processed data and then quantify the accident impacts through outlier detection and 2) to evaluate the duration of impacts by means of hazard-based model with heterogeneity. The procedure developed in this paper will be useful for capturing the accident impacts duration at or near urban intersections, as well as identifying the causal factors that affect these impacts, which includes the accident features, road environment and the temporal characteristics of nearby intersections. These findings could make some valuable conclusions for a better traffic management.