AIS (Automatic Identification System) data provides valuable input parameters in ship traffic simulation models for risk analysis and the prevention of shipping accidents. This paper reports on the detailed analysis of AIS data for modeling purposes. This analysis is focused on restricted waterways to support inland waterway simulations, comparing the differences between a narrow waterway in the Netherlands (narrow waterway in the Port of Rotterdam) and a wide one in China (wide waterway of Yangtze River close to the Su-Tong Bridge). It is shown that straightforward statistical distributions can be used to characterize position, speed, heading and interval times for different types and sizes of ships. However, the distributions for different characteristics of ship behaviors for narrow and wide waterways differ significantly.
Noble metals supported on substrates have been proven as highly efficient catalysts for the reduction of nitrocompounds. However, their large-scale applications are still limited by the problems of fouling and transport during the mass production process. Herein, we first fabricated a spherical montmorillonite (Mt) substrate via spray drying technique, followed by the deposition of Au NPs through polydopamine chemistry to synthesize spherical Au nanoparticles supported Mt (Au@Mt) microspheres. The Au loading is 14.5 wt%, whereas the specific surface area of the Au@Mt microspheres is 47.3 m 2 g −1 , endowing the prepared Au@Mt microspheres with excellent catalytic activity to the reduction of 4-nitrophenol (4-NP) in the presence of NaBH 4 with the optimized apparent reduction rate constant higher than 1.05 min −1. Furthermore, the microspheres can be easily recycled with self-sedimentation without any devices involved and showed excellent stability and recyclability for at least 20 cycles without almost unchanged spherical morphology and catalytic performance. Our straightforward strategy to solve the issue of the mass production process through granulation of amorphous nanomaterial substrate facilitates the practical application of these catalysts in the reduction of nitro-compounds.
Conductive asphalt concrete can be used to help pavement snow melting/deicing by an asphalt pavement electrical heater. It is an emerging technology to ensure safety driving during winter time. Based on the Joule heating law, an electric current passing through the conductive asphalt concrete (a conductor) could generate enough heat to prevent snow accumulation and icing on the asphalt pavement surface. This article provides a review on the material design, construction technique, performance evaluation, and engineering applications of conductive asphalt concrete. The literature shows that the conductivity and mechanical properties of conductive asphalt concrete are strongly dependent on the material compositions and mixing programs. Meanwhile, the mechanism of conductivity improvement is identified according to the characteristics of conductive additives. In addition, the effects of service conditions on the resistivity are evaluated. Asphalt pavement electrical heater technique shows some appreciable advantages in environment protection and traffic safety aspects, although it has few applications in the highway industry. It therefore recommends that further investigations on asphalt pavement electrical heater are indispensable and should focus on some covered issues besides the existing research, such as proper material selection, resistivity stability, desirable high operational efficiency, and suitable construction technique.
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