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The energy consumption of data center cooling systems accounts for a large proportion of total energy consumption. The optimization of airflow organization is one of the most important methods to improve the energy efficiency of cooling systems. The adjustment scale of many current air flow organization methods, however, is too large and does not support the data center's refined operation. In this paper, a new type of air supply terminal device is proposed, and it could adaptively adjust according to the power of servers in the rack for cold air redistribution. In addition, the corresponding regulation strategy is proposed. A CFD model is established according to field investigation of a real data center in Shanghai to investigate the adjustment range and the energy saving potential of the device. The simulation results indicate that the device can suppress the local hot spots caused by excessive server power to some extent and greatly improve the uniformity of servers exhaust temperature. The case study shows that the device can save energy consumption by 20.1% and 4.2% in mitigating local hot spots compared with reducing supply air temperature and increasing supply air flowrate. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this article was to build a radio frequency (RF) coil system to achieve high vessel wall image quality with coverage extending from the aortic arch to the intracranial vessels. Methods: A 48-channel coil system was built and characterized at a 3 tesla (T) Magnetic Resonance Imaging (MRI) scanner (uMR 790, Shanghai United Imaging Healthcare, Shanghai, China). The coil's performance was compared with a commercially available 36-channel coil system. By human studies, signal-to-noise ratio (SNR) units were evaluated and g-factors were calculated in the transverse planes of the brain and neck regions. Results: The SNR was increased by at least 28% in the brain region and up to fourfold in the neck region. The average g-factor with the acceleration factor, R = 3, was lowered by 21% in the transverse plane of the neck region. Intracranial and carotid arterial wall images with an isotropic spatial resolution of 0.63 mm were acquired within 7.7 minutes and thoracic aorta wall images with an isotropic spatial resolution of 1.1 mm were acquired within 2.7 minutes with the 48-channel coil system. The vessel wall can be more clearly visualized with the 48-channel coil system compared with the 36-channel coil system. Conclusion: A 48-channel coil system was developed and demonstrated superior performance for vessel wall imaging at the intracranial and cervical carotid arteries compared with a commercial 36-channel coil. Significance: The 48-channel coil system is potentially useful for clinical diagnostics, especially when attempting to diagnose ischemic stroke. [ABSTRACT FROM AUTHOR]

Spatial-temporal distributions, sources identification and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in overlying water and surface sediments in urban river networks of Shanghai were studied. Analytical results showed that there was a significant seasonal variation in concentrations of ∑ 16 PAHs in water, suspended particulate matter (SPM) and sediment phases in this study area. The PAHs pollution in these multi-phases were in the medium level compared with other areas around the world, and the levels of PAHs contamination in SPM and sediment phases in hierarchical rivers showed TS (the third-order stream) > FS (the first-order stream) > SS (the second-order stream). Two manners of isomer ratios and principal component analysis (PCA) were used to identify PAHs origins, and suggested that combustion processes are dominant for PAHs sources. The ratios of PAHs origins by fossil fuels combustion, coke burning and crude oil in hierarchical rivers were determined with FS > SS > TS in SPM and sediment phases, and the ratio of PAHs origins by traffic emissions was analyzed with TS > SS > FS. PAHs in water samples have a certain impact on aqueous ecological system especially due to the fact that the ∑c eq values of nine PAHs were calculated from 0.715 to 15.831 μg/L in winter, which inferred serious ecological risk to some special aquatic organisms. The calculations of MERMQ in sediment samples showed that the MERMQ values ranged from 0.021 to 1.209 in winter and 0.019 to 0.643 in summer, which suggested high toxicity at six sampling sites in winter and only one location in summer due to high levels of PAHs. Furthermore, the toxicity degree of sediments were demonstrated with TS > FS > SS. [ABSTRACT FROM AUTHOR]

The deposition of polycyclic aromatic hydrocarbon (PAHs) has far-reaching impacts on Earth's surface system and human health. However, a comprehensive understanding of PAHs' deposition in a high urbanized area is still lacking because of limited field measurements data and rough resolution of current models. In this research, a deposition map of PAHs with a resolution of 2 × 2 km in megacity Shanghai, China was established. Gridded annual total deposition of PAHs from July 2020 to June 2021 ranged from 385 to 10,631 ng/(m2·d), with a mean value of 2,611 ng/(m2·d). The highest PAHs deposition was found over the downtown Shanghai, which received 4.3 times the deposition flux of outlying areas. About 77 % of area in Shanghai was dominated by wet deposition which accounted for 62 % of total deposition in Shanghai. The total deposition showed a trend of summer>fall>spring>winter, which was similar to that of the amount of rain. Source apportionment and geographically weighted regression analysis showed that built-up land and human activities are key driving factors of PAHs' deposition in Shanghai. Our results suggest that intensive human activities could alter the PAHs deposition distribution in Shanghai, and improve the understanding of PAHs' environmental behavior in high urbanized area. [Display omitted] • One-year measurement of dry & wet deposition of PAHs in Shanghai was reported. • 2 km × 2 km deposition mapping of PAHs in megacity Shanghai was established by CMAQ. • LMW PAHs dominated wet deposition while MMW and HMW PAHs dominated dry deposition. • Built-up land and human activities are key factors driving PAH deposition. [ABSTRACT FROM AUTHOR]

Abstract: Polycyclic aromatic hydrocarbons (PAHs) were studied in 230 daily fine particulate matter (PM2.5) samples collected in four seasons at urban and suburban sites of Shanghai, China. This study focused on the emission sources of PAHs and its dynamic results under different weather conditions and pollution levels and also emphasized on the spatial sources of PM2.5 and PAHs at a regional level. Annual concentrations of PM2.5 and 16 EPA priority PAHs were 53 μg/m 3 and 6.9 ng/m 3 , respectively, with highest levels in winter. Positive matrix factorization (PMF) modeling identified four sources of PAHs: coal combustion, traffic, volatilization and biomass combustion, and coking, with contributions of 34.9%, 27.5%, 21.1% and 16.5%, respectively. The contribution of traffic, a local-indicative source, increased from 17.4% to 28.7% when wind speed changed from >2m/s to <2m/s, and increased from 18.3% to 31.3% when daily PAH concentrations changed from below to above the annual mean values. This indicated that local sources may have larger contributions under stagnant weather when poorer dispersion conditions and lower wind speed led to the accumulation of local-emitted pollutants. The trajectory clustering and potential source contribution function (PSCF) and concentration weighted trajectory (CWT) models showed clearly that air parcels moved from west had highest concentrations of PM2.5, total PAHs and high molecular weight (HMW) PAHs. While small differences were found among all five clusters in low molecular weight (LMW) PAHs. Sector analyses determined that regional transport source contributed 39.8% to annual PM2.5 and 52.5% to PAHs, mainly from western regions and varying with seasons. This work may make contribution to a better understanding and control of the increasingly severe air pollution in China as well as other developing Asian countries. [ABSTRACT FROM AUTHOR]

Understanding the impact of polycyclic aromatic hydrocarbons (PAHs) on soil environments is of increasingly important concern. Therefore, the microbial degradation of PAHs in soils has drawn considerable attention, but little is known about the PAH degradation genes in urban soils. In this study, we examined the diversity and abundance of the PAH degradation bacteria and evaluated whether the specific bacteria can reflect PAH contents in the soils from urban roadsides directly receiving traffic emission. The results of phylogenetic analysis indicated that low PAH degradation bacterial diversity occurred in the urban roadside soils, only including Mycobacterium sp., Terrabacter sp., and one novel cluster. The community composition diversity of PAH degradation bacteria did not show a significant difference across the sampling sites. The abundance of PAH degradation genes ranged from 5.70 × 10 to 6.44 × 10 gene copies g dry soil, with an average abundance of 1.43 × 10 gene copies g dry soil, and their spatial variations were related significantly to PAH contents in the soils. The Mycobacterium sp. was the most widely detected and estimated to occupy 65.9-100 % of the total PAH degradation bacteria at most of the soil samples, implying that the Mycobacterium sp. might play a primary role in degrading PAHs in the contaminated urban soil environments. [ABSTRACT FROM AUTHOR]

• Characteristics of integrated uses of ridesourcing and DBS with metros are studied. • Integrated DBS and ridesourcing trips are concentrated in different areas. • Proportion gap between two modes reaches a peak in distance interval of 0–0.5 km. • The most travel time of integrated trips is within 14 min. • The built environment has different impacts on the two integrated uses. To enhance the last-mile connectivity of metros, transport managers are experimenting with the integration of shared mobility modes, such as dockless bike sharing (DBS) and ridesourcing. To provide theoretical guidance for transport managers, it is imperative to deepen knowledge of the differences between the integration of DBS and ridesourcing with metros. A three-level structure was developed in this study to identify integrated DBS and ridesourcing trips using observed data from DiDi and Mobike in Shanghai, China. The travel characteristics of two identified integrated shared mobility modes were then compared. Finally, negative binomial regression models were built to investigate the factors influencing these two integrated uses. Comparative analysis shows that the travel distance intervals with the highest proportions are 0.5–1.0 km for DBS and 1.0–1.5 km for ridesourcing. In terms of temporal distribution, morning peaks of integrated DBS trips are higher and earlier than those of ridesourcing. In the spatial dimension, integrated DBS and ridesourcing trips are mainly concentrated in the central urban area and suburban areas, respectively. Further examination indicates that the built environment has different impacts on these two integrated uses. These results provide an improved understanding of the seamless integration of shared mobility modes with metros. [ABSTRACT FROM AUTHOR]

The article assesses the usefulness of patch testing with the European standard series to the diagnosis of contact dermatitis in Shanghai, China. All 88 patients with suspected contact dermatitis were included. More than 2 weeks after skin lesions had disappeared, all patients were patch tested by three experienced dermatologists, with the European standard series and other supplementary substances suspected from their history. 41 of the 88 patients were positive on patch testing. 30 to the standard series and 21 to other substances. The most common allergens were nickel sulphate, potassium dichromate and fragrance mix. Results show that the European standard series is applicable to patch testing in Shanghai.

Polycyclic aromatic hydrocarbons (PAHs) were studied in dry and wet deposition samples collected at urban and suburban sites of Shanghai, China from April 2014 to April 2015. Average wet deposition fluxes of PAHs were higher than dry deposition (62.6 ± 41.5 vs. 26.9 ± 14.4 μg/m 2 /day). However, dry deposition removed more PAHs than wet deposition (69% vs. 31%) due to much shorter durations of wet deposition. The highest dry and wet deposition fluxes were in fall and winter, respectively. The highest amount of dry deposition was in fall and the highest of wet deposition was in summer. The contribution of wet deposition to total deposited PAHs in Shanghai, East China was higher than that in northern China and lower than that in southern China. The difference can be explained by both precipitation amount and removal efficiency (washout ratio). Average dry deposition velocity and washout ratio of particle-associated PAHs were 5.2 cm/s and 5.8 × 10 4 , respectively. Four sources of deposited PAHs were unraveled by positive matrix factorization (PMF) model: traffic, coal combustion, coking and volatilization, contributing 28.7%, 24.6%, 23.7% and 23.0%, respectively. More contribution of traffic and less coal combustion and volatilization were found at urban than at suburban site. As the connection between aerosol and surface soil, deposition had a different PAH composition from those in the two sides, containing more low MW PAHs. That arose the concern that dry deposition velocity and particle washout ratio could be overestimated if coarse particulate matter was excluded from the calculation. Although deposition has been considered as the predominant pathway of PAHs to urban surface system, the PAH composition in street dust differed drastically from that in deposition. This indicated that other sources (e.g. traffic) in urban system could have a greater contribution to PAHs than it had been identified in deposition samples. [ABSTRACT FROM AUTHOR]

The urban environment is an essential source and sink of polycyclic aromatic hydrocarbons (PAHs). However, there is a paucity of knowledge regarding the pollution state of PAHs and their controlling factors in urban soil columns. We therefore quantified PAHs, black carbon (BC), and total organic carbon (TOC) in 24 1-m-deep urban soil columns collected from nearby areas of power plants (P), industrial parks (I) and environmental companies (E) from Shanghai Metropolitan Area, China. The results showed that the total concentrations of USEPA 16 PAHs varied from 91.5 to 46834.5 ng g −1 , and the average pollution level followed the pattern P > I > E. The vertical migration of PAHs obeyed the exponential decay model in undisturbed soil columns. However, anthropogenic factors (land use and artificial disturbance) and edaphic conditions (BC and TOC contents as well as particle size) were strong influencing factors for the PAHs’ fate in urban soils. Coal combustion and vehicle sources were identified as dominant PAH sources. Risks based on both the total benzo[ a ]pyrene equivalent (BaP eq ) values and the incremental lifetime cancer risk (ILCR) values showed a general trend as P > I > E. For most sites, the ecological risks were below the threshold safe value of 600 ng BaP eq g −1 , and ILCR values were at the negligible risk level in I and E. However, dermal contact to soils, especially the deep soil layers in P, have potential health risks and should draw enough attention. Our findings thus supplemented knowledge regarding the vertical distribution and migration of PAHs, showed the predictive power of BC and TOC for PAH fate, and revealed the importance of monitoring and managing urban soils in deeper layers not just surface layers. [ABSTRACT FROM AUTHOR]

Air pollutions from transportation sector have become a serious urban environmental problem, especially in developing countries with expending urbanization. Cleaner technologies advancement and optimal regulation on the transporting behaviors and related design in infrastructures is critical to address above issue. To understand the spatial and temporal emissions pattern within transportation lays the foundation for design on better infrastructures and guidance on low-carbon transportation behaviors. The feasibility of Global Positioning System (GPS) and emerging big data analysis technique enable the in-depth analysis on this topic, while to date, applications had been rather few. With this circumstance, this paper analyzed the taxi's energy consumption and emissions and their spatial-temporal distribution in Shanghai, one of the most famous mega cities in China, applying big data analysis on GPS data of taxies. Spatial and temporal features of energy consumptions and pollutants emissions were further mapped with geographical information system (GIS). Results highlighted that, spatially, the energy consumption and emission presented a distribution of dual-core cyclic structure, in which, two hubs were identified. One was the city center, the other was Hongqiao transport hub, the activities and emission was more concentrated in the west par of Huangpu River. Temporally, the highest activity and emission moment was 9–10AM, the second peak occurred in 7–8PM, which were both the traffic rush period. The lowest activity/emission moment was 3–4AM. Causal mechanism for such distribution was further investigated, so as to improve the driving behaviors. Through the exploration of spatial and temporal emissions distribution of taxis via big dada technique, this paper provided enlightening insights to policy makers for better understanding on the travel patterns and related environmental implications in Shanghai metropolis, so as to support better planning on infrastructures system, demand side management and the promotion on low-carbon life styles. [ABSTRACT FROM AUTHOR]