Time dimension analysis: Comparison of Nanjing local driving cycles in 2009 and 2017
SUSTAINABLE CITIES AND SOCIETY
Authors: Yang, Yang; Li, Tiezhu; Zhang, Tao; Yu, Qian
Abstract
Driving cycles are widely used as standard measurement procedures for vehicle emissions and energy consumption assessment, especially for vehicle design optimization and performance evaluation of emerging vehicular technologies (HEV/EV), including standard driving cycles and non-standard driving cycles. Local driving cycles, as non-standard driving cycles, are mainly used in certain areas for in-use vehicle emission and fuel consumption assessment. However, whether these local driving cycles could represent the driving conditions in certain areas for a long time, and whether it is necessary to consider the year of development when comparing local driving cycles in different cities, these issues require more attention from researchers. In this paper, a practical local driving cycle construction methodology combing principal components analysis (PCA) and K-means clustering is proposed, and two local driving cycles for passenger cars in Nanjing are developed in 2009 and 2017, respectively. The same data acquisition and processing methods make the comparison between the two generated cycles more fair. Significant differences in driving parameters between Nanjing local driving cycles in 2009 and 2017 show the necessity of studying local driving cycles from time dimension and provide traffic management authority with some valuable advice on estimating road-based vehicle emission.
Occurrence of Staphylococcus spp. and investigation of fecal and animal viral contaminations in livestock, river water, and sewage from Tunisia and Romania
ENVIRONMENTAL MONITORING AND ASSESSMENT
Authors: Rahmani, Faten; Hmaied, Fatma; Matei, Ioana; Chirila, Flore; Fit, Nicodim; Yahya, Mariem; Jebri, Sihem; Amairia, Safa; Hamdi, Moktar
Abstract
The objective of this study was to determine the occurrence of Staphylococcus spp., Escherichia coli, somatic coliphages, F-specific RNA bacteriophages, hepatitis E virus (HEV), and bovine enterovirus (BEV) in fecal and water samples. The occurrence of Staphylococcus spp. was investigated in treated wastewater samples collected from slaughterhouse of Tunisia. Results showed that Staphylococcus spp. were detected in the totality of collected samples with an average mean of 5.44 Log(10) (CFU/100 ml). Regarding fecal indicator bacteria, E. coli was detected in the totality of water samples and was more abundant in Tunisian samples than in samples collected from Romania (P<0.05). Concerning somatic coliphages and F-specific RNA bacteriophages used as viral indicators, they were detected in all raw and treated wastewaters. Bovine enterovirus (BEV) was detected in 20.1% and 28% of bovine stool samples collected from Tunisia and Romania, respectively. BEV was also detected in 60% of porcine stool samples from Romania. BEV was absent in all treated sewage samples. HEV was detected in raw sewage and bovine fecal sample from Romania with low occurrence and none sample from Tunisia was positive. This study may give us an insight into the monitoring of water quality in Tunisia and Romania.