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Mopeds (electric bicycles and light motorcycles) are commonly used as a personal transportation mode in China. However, the understanding of characteristics of left-turning mopeds at signal-controlled intersections has been relatively limited. To bridge this gap, firstly, this paper proposed a video conversion method of moped movement data acquisition. Then, a method of data accuracy verification was introduced by comparing the results between the field experiment and the video conversion method. Secondly, the ideal traffic space for left-turn mopeds from different entrances was defined to analyse the characteristics of the left-turning mopeds at intersections. Further, three indicators, namely, transverse distance, the proportion of left-turning mopeds with crossing behaviour, and the average number of avoidance behaviour, were proposed and used to analyse the asymmetrical characteristics behaviour, crossing behaviour, and avoidance behaviour. Finally, based on empirical data collected from five signal-controlled intersections, the proposed methods and behaviours were analysed. This paper provides both a valid method of obtaining the position data of mopeds and a reliable basis for improving the safety of left-turning moped riders at urban signal-controlled intersections.

In this study, polyethylene filter cotton (PFC) was used as a suspended biocarrier to remove ammonium from aquaculture ponds. The concentration of the ammonia-oxidizing bacteria (AOB amoA gene reached ~107 copies cm−3 in the PFC after 16–19 days of incubation, whereas only 101–102 copies cm−3 were present in the aquaculture water. The effects of temperature, pH, and dissolved oxygen (DO) concentration on the nitrification rate were evaluated in the laboratory. The nitrification rate of PFC enriched with AOB reached 0.035 ± 0.002 mg N cm−3 PFC h−1 measured at pH 7.0–8.5, 28 °C, and a DO concentration of 6.0–7.0 mg L−1. These results suggest that the use of PFC as a suspended biocarrier in aquaculture ponds is a feasible and cheap method for removing ammonium ion in situ.

The nonpayment area at urban transit stations in China usually becomes extremely crowded during peak hours because many passengers queue to buy tickets and pass through the fare gates. How to evaluate the performance of these activities is a critical issue for the design and management of the nonpayment area. This study used microscopic simulation models to investigate passenger behavior in the nonpayment area. The study developed a queue choice model, a passenger movement model, and a path navigation model. Some new ideas were involved. First, the study introduced the concepts of dynamic queue length and dynamic distance between the current passenger and alternative queues into the queue choice model. Second, a new factor, called direction of goal, was proposed to navigate a passenger through the dynamic end of a queue or other goals. This factor was used to construct the transition probability function of a cellular automata model. Finally, the proposed models were calibrated and verified on the basis of a field survey and sensitivity analysis. The results show that the proposed models can capture passenger behaviors in the nonpayment area and perform well for queue estimation.

An annual investigation into the abundance of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in fresh water aquaculture ponds was performed by quantitative PCR of the amoA gene. The results showed that AOB were the main ammonia-oxidizing microorganisms in water, and significantly higher copy numbers of the AOB amoA gene were observed in the summer (Aug 2012), while no significant differences were detected among the other three seasons. AOA showed low abundances throughout the year. The predominance of AOB in aquaculture water was suggested to be related to photoinhibition. Both the AOB and AOA amoA genes in aquaculture pond sediments showed typical seasonal patterns. The maximum density of AOB was observed in the autumn (Nov 2012) and winter (Jan 2013), while the maximum density of AOA was observed in winter. The minimum densities of both AOA and AOB occurred in the summer. The concentration of the AOA amoA gene was higher than that of the AOB amoA gene in sediments by almost one order of magnitude, which indicates that AOA are the dominant ammonia-oxidizing microorganisms in the aquaculture pond sediments. Dissolved oxygen is suggested to be the key factor determining the predominance of AOA in pond sediments.

The configuration of service facilities, such as ticket vending machines, staffed ticket booths, automatic fare gates, and escalators, is an important issue for the plan and design of rail transit stations. Reasonable configuration of service facilities is based on a good understanding of the passenger traffic characteristics of such service facilities, which are affected by passenger characteristics, station types, and facility performance. To study the passenger traffic characteristics of service facilities, five stations are selected in Shanghai, and their passenger traffic data are collected and analyzed. In this study, the results indicate that service-time frequencies of ticket vending machines and staffed ticket booths follow Weibull distribution and exponential distribution, respectively, and that the headway of passengers passing the automatic fare gate under ideal conditions follows normal distribution. According to the service time and headway distributions of ticket-selling facilities ...