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The Coronavirus Disease 2019 (COVID-19) pandemic has brought unprecedented challenges to urban transportation. During the pandemic, public transportation, as an integral part of urban transportation, must ensure the safety of passengers, particularly low-mobility individuals (LMIs): older people, individuals with disabilities, and low-income individuals who prefer getting around by it. Based on passengers' travel behavior and psychological characteristics, this paper analyzes the public transportation travel of LMIs before and during the pandemic using a hybrid survey method that combines a face-to-face survey and a supplementary telephone interview. The results show that LMIs differ from the general public in public transportation travel characteristics, and the three subgroups also differ from each other. Accordingly, the conditions in the context of the pandemic should be fully considered to meet LMIs' demand for public transportation and ensure their safety when relevant policies are formulated. [ABSTRACT FROM AUTHOR]

Large-span spatial lattice structures generally have characteristics such as incomplete modal information, high modal density, and high degrees of freedom. To address the problem of misjudgment in the damage detection of large-span spatial structures caused by these characteristics, this paper proposed a damage identification method based on time series models. Firstly, the order of the autoregressive moving average (ARMA) model was selected based on the Akaike information criterion (AIC). Then, the long autoregressive method was used to estimate the parameters of the ARMA model and extract the residual sequence of the autocorrelation part of the model. Furthermore, principal component analysis (PCA) was introduced to reduce the dimensionality of the model while retaining the characteristic values. Finally, the Mahalanobis distance (MD) was used to construct the damage sensitive feature (DSF). The dome of Taiyuan Botanical Garden in China is one of the largest non-triangular timber lattice shells worldwide. Relying on the structural health monitoring (SHM) project of this structure, this paper verified the effectiveness of the damage identification model through numerical simulation and determined the damage degree of the dome structure through SHM measurement data. The results demonstrated that the proposed damage identification method can effectively identify the damage of large-span timber lattice structures, locate the damage position, and estimate the degree of damage. The constructed DSF had relatively strong robustness to small damage and environmental noise and has practical application value for SHM in engineering. [ABSTRACT FROM AUTHOR]

Historical sites are incomplete relics left by human activities and are also valuable resources for human society, with most of them buried deep underground. Because the protection of original historical sites is difficult, very few sites choose this method. Many funerary objects that have been in historical sites are scattered in museums, losing their original context and complicating their utilization. Thus, using digital technology to protect and utilize historical sites and to explore their outstanding value from historical, aesthetic, and anthropological perspectives is a foremost concern. Therefore, this study aims to develop a comprehensive method for the protection and utilization of historical sites, that is, digital protection and utilization based on a digital twin. We constructed a historical site digital twin model using qualitative and vertical methods, including a physical entity, virtual entity, twin data center, digital twin service, and connection. We also established a technical framework of data acquisition and processing, digital protection, and digital utilization, forming a layered management and application of digital resources. In digital protection, information in the real world and the virtual world are connected to monitor risks, collect data, create simulations, and propose protection strategies, quickly and accurately. In digital utilization, the knowledge graph is constructed to associate seemingly unrelated information, explore potential knowledge, and improve information sharing. In addition, the method is validated by means of case studies of historical sites in China. In this paper, the historical sites of the Northern Qi Dynasty in Taiyuan, Shanxi, especially the Xuxianxiu Tomb and Lourui Tomb, are discussed in detail. The results indicate that this method is effective for the protection and utilization of historical sites. [ABSTRACT FROM AUTHOR]

It is of importance to enhance the urban areas' capacity for population aggregation in underdeveloped regions, aiming to rectify the imbalanced and insufficient pattern of economic development in China. Taking the Taiyuan Metropolitan Area (TMA) in central China as a case study, this paper examines the evolutionary process and characteristics of population agglomeration from 2000 to 2020, and identifies factors associated with agglomeration and their spatial effects. The findings indicated that: 1) against the background of sustained population shrinkage in the provincial area, the TMA showed a demographic trend of steady increase, albeit with a decelerated growth rate. In the metropolitan area, urban population size continued to grow rapidly, whereas the rural areas endured sustained losses. Disparities in city size continued to widen, and the polarization of concentrated population in the core cities kept increasing. 2) Agglomerations in both secondary and service industries had significant positive effects on local population agglomeration, with the former effect being stronger. Regional economic development, government fiscal expenditure, and financial advancement all contributed to facilitating local population clustering. From a spatial spillover perspective, service agglomeration and financial development promoted population agglomeration in surrounding areas. Conversely, fiscal expenditure inhibited such agglomeration. As for industrial agglomeration and regional economic development, their spatial spillover effects were non-significant. The results obtained reveal several policy implications aimed at enhancing the population agglomeration capacity of the metropolitan area in underdeveloped regions during the new era. [ABSTRACT FROM AUTHOR]

Industrialization has brought serious pollution problems to the eco-environment and severely weakened the ecosystem services in industry-concentrated areas. There are few studies choosing a heavy industrial city to evaluate the impacts of industrial pollution on ecosystem services and examine the relationships between industrial pollution and ecosystem services. This paper selected Taiyuan, an important energy resources and heavy chemical industry base in China, as a case study to quantitatively analyze the relationships between industrial pollution and ecosystem service value (ESV). The results showed that the pollution level of industrial solid waste decreased first and then increased, the pollution level of industrial wastewater presented a downward-upward-downward trend, whereas the pollution level of industrial waste gas continued to decrease during the study period. The total ESV increased from 8.56 billion Yuan in 2005 to 10.49 billion Yuan in 2017. Climate regulation and hydrology adjustment contributed the most value to the total ESV (more than 60%). The ESV of water supply was negative and decreased the most value (−177.52 million yuan). The fitting regression indicated that the ESV and the pollution levels of industrial wastewater, industrial waste gas and industrial solid waste exhibited significant negative correlations, which could be expressed as quadratic functions. These findings could provide valuable references for the coordination between industrial development and ecological conservation. [ABSTRACT FROM AUTHOR]

• Propose a risk-based analysis model to assess freight train derailment at railway turnouts. • Improved probabilistic approach coupled with IFFTA, Noisy or gate and BN model. • Preventive measures are provided to reduce derailment and secondary damages. • The paper contributes to reduce the failure risk of train-turnout system. Derailment is one of the main hazards during train passes through railway turnouts (RTs) in classification yards. The complexity of the train-turnout system (TTS) and unfavorable operating conditions frequently cause freight wagons to derail at RTs. Secondary damages such as hazardous material spillage and train collisions can result in loss of life and property. Therefore, the primary goal is to assess the derailment risk and identify the root causes when trains pass through RTs in classification yards. To address this problem, this paper proposes a failure probability assessment approach that integrates intuitionistic fuzzy fault tree analysis (IFFTA) and Noisy or gate Bayesian network (NGBN) for quantifying the derailment risk at RTs. This method can handle the fact that the available information on the components of the TTS is imprecise, incomplete, and vague. The proposed methodology was tested through data analysis at Taiyuan North classification yard in China. The results demonstrate that the method can efficiently evaluate the derailment risk and identify key risk factors. To reduce the derailment risk at RTs and prevent secondary damage and injuries, measures such as optimizing turnout alignment, controlling impact between wagons, lubricating the rails, and regularly inspecting the turnout geometries can be implemented. By developing a risk-based model, this study connects theory with practice and provides insights that can help railway authorities better understand the impact of poor TTS conditions on train safety in classification yards. [ABSTRACT FROM AUTHOR]

• There are significant satisfaction differences in bus traveling before and after COVID-19. • COVID-19 has severely affected satisfaction with bus traveling of low-income individuals. • Low-income individuals' satisfaction with bus traveling is determined by socioeconomic attributes rather than traveling attributes after COVID-19. • Risk concern has a significant positive impact on risk perception, but risk concern and risk perception have only a minor impact on satisfaction before and after COVID-19. • There is a significant relationship between satisfaction levels and modes of traveling alone and traveling with companions by bus. Although all cities in China have promulgated public transportation control measures to choke off the spread of COVID-19, it also has brought severe changes to low-income individuals' bus traveling. However, the study focusing on satisfaction differences in bus traveling before and after COVID-19 is far under-researched, this paper therefore explored satisfaction differences among low-income individuals under socioeconomic attributes, traveling attributes, and psychological attributes by using the data consist of interviews addressed to 930 individuals in Taiyuan, China. Furthermore, the relationship between satisfaction levels and modes of traveling alone and traveling with companions by bus has also been deeply analyzed to reduce single-person driving problem. As a result, many exciting phenomena were discovered: the significant factors affecting low-income individuals' satisfaction occur "shift" on a large scale after COVID-19; risk concern has a significant positive impact on risk perception, but risk concern and risk perception have only a minor impact on satisfaction before and after COVID-19; it was found that there is a significant relationship between satisfaction levels and modes of traveling alone and traveling with companions by bus. Understanding them can be a reference for improving the travel environment between low-income individuals. [ABSTRACT FROM AUTHOR]

Seven pieces of gold foils for surface decoration of the lacquerware were excavated in the late Western Han Dynasty tomb in the area of the Jin Yang (晋阳) Ancient City site in Taiyuan (太原), Shanxi (山西), China. These gold foils portray images of the carriage, the leopard, the tigers, the ox, and the dancer with fluttering sleeves, etc., with black lines outlining the contours and red paint depicting vivid patterns. The study used Stereo Microscopes, Metallurgical Microscopy, Environmental Scanning Electron Microscopy coupled with Energy-Dispersive X-ray Spectroscopy (ESEM-EDS), and Laser Raman Spectroscopy (LRS) to analyse the thickness of the gold foils, the alloy composition, the composition of the paint and other surface attachments, and investigate the manufacturing process. As the results show, the thickness of the gold foils is about 26 μm. The composition is a gold-silver alloy with about 96% Au/(Au + Ag) (surface) and 98% Au/(Au + Ag) (cross-section). The metallurgical observation shows that the gold foils underwent heating and forging. The black lines on the front side are Chinese ink lines, with cracking and peeling phenomenon, and parallel polishing lines can be seen at the peeling places, while no polishing lines are observed on the back side. Some red paint made of cinnabar is above the black lines, and the binder is organic. Some lacquer residues are found on the back. According to the results of the study, the manufacturing process of the gold foils applied on the lacquerware is as follows: the gold foils are obtained by heating and forging, the front sides of the gold foils are polished, the shapes are carved out, and the gold foils are pasted on the lacquerware when the lacquerware's surface is not yet dry. The gold foils are painted with black Chinese ink and red cinnabar pigment. The study's results offer important references for understanding the manufacturing craft of the gold foils applied on the lacquerware in the late Western Han Dynasty of China and guide the conservation of the lacquerware decorated with painted gold foils. [ABSTRACT FROM AUTHOR]

[Display omitted] • A methodological framework to delineate the provision area for the wind erosion prevention service based on the carrier dynamics of ecosystem service flows; • A computational framework to determine ecosystem service transmission pathways; • Methods to calculate the realized ecosystem service value distribution within the service provision area; • Implications on urban ecological hinterland delineation and precise ecological compensation program design. Many ecosystem service (ES) items, such as the wind erosion prevention service (WEPS), have spatially separated service provision and benefit areas (SPA & SBA), which are connected by directional ecosystem services flows (ESF). Clarifying the specific spatial relationships between the SPA and SBA is of potential scientific and policy importance for such directional flow-conveyed ES. Much of the existing research has focused on the identification of SBA based on a given SPA. However, due to the asymmetry of supply-based and demand-based ESFs and geospatial heterogeneity, this relationship cannot be directly inferred backward to obtain the SPA for a given SBA. In this paper, we propose a methodological framework along with computational methods to delineate the SPA of a given SBA. Our methods feature ESF carrier dynamics-based algorithms to determine the specific path of the ESF which is enabled by an adapted Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model, as well as quantification approaches for evaluating the actual realization of ecosystem services value (RESV) with the support of the Revised Wind Erosion Equation (RWEQ) model. We demonstrate the applicability of our methods with the example of three mega-cities in northern China that are severely affected by the wind erosion problem. The results show that the spatial distribution of wind erosion source areas in the three cities are different, and the SPA based on the trajectory weights shows a decreasing trend from the city center to periphery, with those in the cities of Beijing and Taiyuan mainly concentrated in the northwestern direction, while the high RESV zones in the SPA are mainly concentrated in the desert areas. In the time series, wind erosion affecting these three cities mainly occurred in late April and May. The study provides a methodological and empirical basis for applied ecological analysis including the delineation of the ecological hinterlands of cities, or the formulation of precise ecological compensation programs. [ABSTRACT FROM AUTHOR]

Besides its systematic identification with disasters and hazards, resilience could be a powerful tool for understanding changes in the built environment. This study analyses the development of the workers' residential area in an industrial community (IC) in China after its economic transformation. How can a resilience approach help analyze the impact of economic changes on the built environment? ICs were self-contained and multifunctional compounds that first emerged in socialist China in the 1950s and were used to organize social production (factory) and collective life (workers' residential areas). Although existing research has explored the possible changes in the built environment of ICs before and after economic transformation, these changes that have either taken place or are still happening have never been quantified. Additionally, the impact of changes in the level of enclosure of workers' residential areas after the factory bankruptcy, a distinctive aspect of the built environment, has seldom been explored. Thus, this study uses a resilience approach to analyze the impact of changes in the level of enclosure on the built environment of the workers' residential area after the factory bankruptcy by taking the case of Shanxi Knitting Factory (SKF) in Taiyuan, China. This study seeks to use resilience to understand changes in ICs under the background of China's economic transformation. The finding shows that the factory bankruptcy significantly impacts the changes in the built environment of its workers' residential area, as well as affecting the level of enclosure in the built environment. With the disappearance of enclosures after the factory bankruptcy, the workers' residential area of the SKF is gradually shifting from an enclosed, isolated, and self-contained industrial auxiliary facility to an open, diversified, and heterogeneous space. It is gradually integrating into the surrounding urban neighborhoods. [ABSTRACT FROM AUTHOR]

As the essential component of shale, clay minerals have a vital influence on the pore structure and the gas content of reservoirs. To investigate the compositional characteristics of coal-measure shale and its effects on pore structure, a total of thirteen Taiyuan formation shale samples were collected from the Qinshui Basin and were analyzed using a combination of X-ray diffraction analysis, X-ray fluorescence spectrometry, Fourier transform infrared spectroscopy (FE-SEM), polarized optical microscopy, and field emission scanning electron microscopy. The results show that the principal minerals of the samples are quartz, kaolinite, and illite. Most of the kaolinite was an original terrigenous detrital material with low crystallinity and a low degree of ordering, whereas the illite was mainly composed of 1Md resulting from diagenesis. Clay minerals developed slits, irregularly-shaped or multisized pores during diagenesis, which can be classed into interlayered pores, intergranular pores, and microfractures. Eight micro-morphological forms of clay minerals were summarized based on FE-SEM observations, such as compacted, parallel, bent, tilted, mutually supporting structures, etc., which are mainly formed by the mechanical compaction of clay minerals with different sizes, shapes, and contact relationships. The diversity and complexity of the micro-morphological forms of clay minerals contribute to the strong heterogeneity, low porosity and high permeability anisotropy of shale. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are an important class of pollutants in China. The land use regression (LUR) model has been used to predict the selected PAH concentrations and screen the key influencing factors. However, most previous studies have focused on particle-associated PAHs, and research on gaseous PAHs was limited. This study measured representative PAHs in both gaseous phases and particle-associated during the windy, non-heating and heating seasons from 25 sampling sites in different areas of Taiyuan City. We established separate prediction models of 15 PAHs. Acenaphthene (Ace), Fluorene (Flo), and benzo [g,h,i] perylene (BghiP) were selected to analyze the relationship between PAH concentration and influencing factors. The stability and accuracy of the LUR models were quantitatively evaluated using leave-one-out cross-validation. We found that Ace and Flo models show good performance in the gaseous phase (Ace: adj. R2 = 0.14–0.82; Flo: adj. R2 = 0.21–0.85), and the model performance of BghiP is better in the particle phase (adj. R2 = 0.20–0.42). Additionally, better model performance was observed in the heating season (adj R2 = 0.68–0.83) than in the non-heating (adj R2 = 0.23–0.76) and windy seasons (adj R2 = 0.37–0.59). Those gaseous PAHs were highly affected by traffic emissions, elevation, and latitude, whereas BghiP was affected by point sources. This study reveals the strong seasonal and phase dependence of PAH concentrations. Building separate LUR models in different phases and seasons improves the prediction accuracy of PAHs. [ABSTRACT FROM AUTHOR]

To characterize seasonal carbonaceous aerosol pollution in Taiyuan, a typical city in North China that mainly relies heavily on coal, a total of 124 PM2.5 samples were collected from August 2018 to the next May. The annual mean PM2.5 concentration was 83.8 ± 48.5 μg m−3, with a seasonal rank of winter (117.4 ± 47.6 μg m−3) > spring (79.2 ± 34.3 μg m−3) > fall (67.3 ± 34.7 μg m−3) > summer (31.8 ± 6.5 μg m−3), suggesting that fine particulate pollution was still serious in cold seasons. Organic carbon (OC) and elemental carbon (EC) showed similar seasonal patterns with PM2.5. The mean concentration values of OC in summer, fall, winter, and spring were 5.1 ± 0.9, 11.8 ± 6.4, 22.1 ± 14.9, and 12.2 ± 6.7 μg m−3, respectively. The mean concentration values of EC in summer, fall, winter, and spring were 1.5 ± 0.3, 2.5 ± 1.6, 4.4 ± 2.8, and 2.4 ± 1.5 μg m−3, respectively. The proportion of total carbon aerosol (TCA) was about 31.7%, 33.8%, 30.0%, and 27.0% in PM2.5 in summer, fall, winter, and spring, respectively. The good correlation between OC vs. EC and the high value of OC/EC suggests that coal and biomass combustion were the main emissions in cold seasons, aggravated by adverse meteorological conditions and the dustpan-shaped terrain. The mean annual secondary organic carbon (SOC) concentration was 6.1 ± 7.1μg m−3, representing 38.7% of the OC content. The present results presented the serious carbonaceous particulate pollution, which might affect haze pollution in cold seasons. [ABSTRACT FROM AUTHOR]

Ground subsidence is an important geomorphological phenomenon in mining areas. It is difficult to monitor and predict ground subsidence with high precision, especially in mountainous mining areas. Taking the mining workface of a mountainous coalfield in Taiyuan City, in the Shanxi Province of China as an example, this research selects five typical points from GPS observation data along the strike section. Based on the materials, the ground subsidence processes at these typical points are monitored and predicted using the mountainous time function method. Acquired from the mountains time function is a recurrence equation, which is regarded as the state equation, and the Ensemble Kalman (EnKF) method is conducted accordingly. Finally, the performance of the two methods is evaluated and compared using error curves and indexes. This research presents a recurrence equation based on the mountainous time function method and establishes the EnKF method for ground subsidence monitoring and prediction. Meanwhile, compared to the mountainous time function method, the values of the ME, MAE, RMSE and MAPE indexes are largely improved for the EnKF method. Hence, this research not only presents an effective method for ground subsidence monitoring in mountainous mining areas, but also provides theoretical support for safe coal mining and environmental protection. [ABSTRACT FROM AUTHOR]

The types of land used for farmland can greatly influence the source and accumulation risk of heavy metals in soil. However, the apportioning quantitatively the source of soil heavy metals has been studied insufficiently, especially in terms of different types of farmland. In this study, a total of 252 soil samples were taken from dry land, paddy fields and greenhouse fields in the Jinyuan district of Taiyuan city, China, to assess the accumulation risk of heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn). The results were then integrated, and source apportionment was evaluated by geospatial analysis, multivariate statistical analysis and positive matrix factorization (PMF). Cr, Cd and Hg were the dominant pollutants in the studied area. Accumulation risk by Cd and Cu was more severe in greenhouse fields than in dry land or paddy fields, whereas As, Hg and Pb had relatively higher accumulation in paddy fields than in dry land or greenhouse fields. Hg was derived mainly from coal combustion by atmospheric precipitation for the three types of farmland. Long-term irrigation using sewage is the main reason for the accumulation of Cu and Ni in dry land soil, Cu and Zn in paddy field soil and Zn in greenhouse soil. Cd in dry land, Cd and Pb in paddy fields and Cd, Cu, Ni and Pb in greenhouse fields were primarily added to soil through fertilization. Sewage irrigation and fertilization were the dominant sources of heavy metals for paddy field (31.3%) and greenhouse field (33.1%), respectively. [ABSTRACT FROM AUTHOR]

This study assessed the dynamic variations in ecosystem service value (ESV) in response to land-use changes under rapid urbanization and evaluated the coordinated relationship between economic development and ecological conservation by establishing the eco-economic harmony (EEH) index evaluation model. Taiyuan, the resource-based city in China, was selected as a study area. The results show that the total ESV in Taiyuan increased from 8.95 billion Yuan in 2005 to 9.31 billion Yuan in 2016. The ESVs of all land-use types experienced a decrease except for woodland and grassland. Climate regulation and hydrology adjustment were the dominant two ecosystem service functions in the study area. The ESV of climate regulation increased the most (382.62 million Yuan) but water supply decreased the most (−47.91 million yuan). The relationships between economic development and ecological conservation have experienced the evolution process of low conflict–potential crisis–low conflict from 2005 to 2016, indicating that the contradiction between economic development and ecological conservation is becoming increasingly serious over time. Therefore, scientific land-use policies and environmental protection strategies are urgently needed for achieving a sustainable development. This study provides valuable guidance for sustainable urban planning decision-making on maintaining the balance between economic development and ecological conservation under rapid urbanization. [ABSTRACT FROM AUTHOR]