A Practical Accessibility Evaluation Method for Port-Centric Coal Transportation Chains: Considering the Environment and Operational Adaptability

Improving the accessibility of coal transportation is a crucial issue for energy security, national defense, and livelihoods. In this study, a method to evaluate the performance of the port-centric coal transportation chain (PCTC), which is a crucial part of the international coal production and delivery process, is proposed. After analyzing the features of the port-centric coal transportation chain, a practical accessibility evaluation model is established based on the gravity model. Both the foreland and hinterland features are considered in the model. Based on the features of coal transportation, the concept of port operational adaptability is introduced to indicate the port’s ability to manage a fluctuating irregular workload. Moreover, environmental factors, including transportation emissions and dust pollution, are included in the evaluation system. Based on real data collected from China’s north-south coal transportation corridor, a case study presents the implementation of this comprehensive evaluation system in practice. This evaluation system enables us to determine the vulnerable areas in the coal maritime transportation network and provides a decision-making basis for both shippers and port owners

Mass Testing and Characterization of 20-inch PMTs for JUNO

Main goal of the JUNO experiment is to determine the neutrino mass ordering using a 20kt liquid-scintillator detector. Its key feature is an excellent energy resolution of at least 3 % at 1 MeV, for which its instruments need to meet a certain quality and thus have to be fully characterized. More than 20,000 20-inch PMTs have been received and assessed by JUNO after a detailed testing program which began in 2017 and elapsed for about four years. Based on this mass characterization and a set of specific requirements, a good quality of all accepted PMTs could be ascertained. This paper presents the performed testing procedure with the designed testing systems as well as the statistical characteristics of all 20-inch PMTs intended to be used in the JUNO experiment, covering more than fifteen performance parameters including the photocathode uniformity. This constitutes the largest sample of 20-inch PMTs ever produced and studied in detail to date, i.e. 15,000 of the newly developed 20-inch MCP-PMTs from Northern Night Vision Technology Co. (NNVT) and 5,000 of dynode PMTs from Hamamatsu Photonics K. K.(HPK)