Search

Road traffic transportation has flourished in the process of urbanization due to its advantages, but concurrently it generates harmful environmental vibrations. This vibration issue becomes particularly crucial in production workshops housing precision instruments. However, limited research has been undertaken on this matter. This study aimed to investigate the influence of road traffic-induced vibration on micro-vibrations within a workshop housing precision instruments. A field test was conducted to assess the vibration levels originating from both machinery operation and vehicular traffic. The results indicated that ground-borne vibrations caused by road vehicles decrease with increasing propagation distance, peaking around 10 Hz. Machinery operation vibrations were primarily concentrated above 20 Hz, while vehicular traffic vibrations were more prominent below 20 Hz. Notably, the passage of heavy trucks significantly impacted both ground and workshop vibrations, with vertical vibrations being particularly significant. Within the workshop, the second floor experienced higher vibrations above 20 Hz due to the presence of installed instruments. Importantly, the micro-vibration levels on both floors exceeded the VC-C limit (12.5 µm/s), highlighting the need to account for road traffic and machinery vibrations in workshop design. These data can be utilized to validate numerical models for predicting road traffic-induced vibrations, aiding in vibration assessment during road planning and design. [ABSTRACT FROM AUTHOR]

Excessive pesticide application in greenhouses leads to elevated levels of pesticide residues, especially in cold seasons, thereby posing a potential dietary exposure risk to the residents' health. This study aimed to investigate 65 pesticides in 469 leafy vegetable samples collected from greenhouses in Liaoning province between October 2018 and May 2020. Overall, the pesticide levels in 96.4% (452/469) of the samples were below the MRLs established by the Codex Alimentarius Commission. The detection rate of 65 pesticides ranged from 0.2% to 11.9%. Multiple pesticide contamination was common, with dimethomorph being the most recurrent contaminant. The dietary risk assessment study revealed obvious differences in chronic and acute exposure risk values. The chronic risk quotients (RQcs) for leafy vegetable samples were 0.001%–3.993%, indicating an acceptable public health risk for the residents. As two leafy vegetables highly consumed in cold seasons in northeast China, the acute risk quotients (RQas) of Chinese cabbage samples were significantly lower than 100%; however, pakchoi samples exhibited RQa values ranging from 0.159% to 580.529%, showing an unacceptable acute dietary risk. This highlights that, compared to the chronic dietary risks, the potential acute dietary risks induced by the pesticides are higher in greenhouse-grown leafy vegetables during cold seasons. [ABSTRACT FROM AUTHOR]

It is practical to carry out sponge cities to manage rain and floods in collapsible loess areas where water resources and water disasters are prominent. The infiltration laws of the partial anti-seepage bioretention in collapsible loess fields are helpful to ensure the effectiveness and safety of sponge city, which were learned from the field test and numerical model. The seepage field and displacement field of loess sites with different collapsibility grades were compared during rainwater infiltration of the bioretention with the numerical model; the suitability and optimization suggestions for foundation treatment of this structure in various sites were proposed. It is found that the infiltration characteristics can be divided into three stages, and the infiltration range of bioretention increases with increasing infiltration time under the same site type, and the higher the collapsibility level of the site is, the more significant the rise in infiltration range. The settlement of adjacent roads in class II and III collapsible fields is far greater than that in class I and is greater than the settlement standard. The facilities' bottom part foundation can be replaced to ensure the functionality of the facilities and the safety of the surrounding roads in the actual project. [ABSTRACT FROM AUTHOR]

With the extensive use of digital signage, precise site selection is an urgent issue for digital signage enterprises and management agencies. This research aims to provide an accurate digital signage site-selection model that integrates the spatial characteristics of geographical location and multisource factor data and combines empirical location models with machine learning methods to recommend locations for digital signage. The outdoor commercial digital signage within the Sixth Ring Road area in Beijing was selected as an example and was combined with population census, average house prices, social network check-in data, the centrality of traffic networks, and point of interest (POI) facilities data as research data. The data were divided into 100–1000 m grids for digital signage site-selection modelling. The empirical approach of the improved Huff model was used to calculate the spatial accessibility of digital signage, and machine learning approaches such as back propagation neural network (BP neural networks) were used to calculate the potential location of digital signage. The site of digital signage to be deployed was obtained by overlay analysis. The result shows that the proposed method has a higher true positive rate and a lower false positive rate than the other three site selection models, which indicates that this method has higher accuracy for site selection. The site results show that areas suitable for digital signage are mainly distributed in Sanlitun, Wangfujing, Financial Street, Beijing West Railway Station, and along the main road network within the Sixth Ring Road. The research provides a reference for integrating geographical features and content data into the site-selection algorithm. It can effectively improve the accuracy and scientific nature of digital signage layouts and the efficiency of digital signage to a certain extent. [ABSTRACT FROM AUTHOR]