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The assembly quality of complex products is pivotal to their lifecycle performance. Assembly precision analysis (APA) is an effective method used to check the feasibility and quality of assembly. However, there is still a need for a systematic approach to be developed for APA of kinematic mechanisms. To achieve more accurate analysis of kinematic assembly, this paper aims to propose a precision analysis method based on equivalence of the deviation source.

A unified deviation vector representation model is adopted by considering dimension deviation, geometric deviation, joint clearance and assembly deformation. Then, vector loops and vector equations are constructed, according to joint type and deviation propagation path. A combined method, using deviation accumulation and sensitivity modeling, is applied to solve the kinematic APA of complex products.

When using the presented method, geometric form deviation, joint clearance and assembly deformation are considered selectively during tolerance modeling. In particular, the proposed virtual link model and its orientation angle are developed to determine joint deviation. Finally, vector loops and vector equations are modeled to express deviation accumulation.

The proposed method provides a new means for the APA of complex products, considering joint clearance and assembly deformation while improving the accuracy of APA, as much as possible.

Due to the lack of industrywide data, now there is only perceptual knowledge, through survey data, that construction firms may face great challenges in geographical diversification. The article aims to provide an objective description on the state of interregional market entry practices in the Chinese construction industry. How these practices are influenced by related set of regional and industry-related factors is further studied.

Description analysis of the practices is first performed based on a first-hand industrial data set including 1,020 projects and 404 construction firms. Combining provincial panel data in the National Bureau of Statistics of China, related regional and industry-related factors on these practices are further analyzed through hierarchical regression models.

(1) Interregional market entry practices are not quite prevalent during the past two decades, only involving 271 projects and 111 firms which accounts for 26.57% and 27.47% of the analyzed subjects respectively; (2) Large, state-owned and experienced firms are more frequently involved in the practices; (3) A number of regional factors such as local market protection and industry scale also significantly impact the practices.

The empirical analysis of this study was conducted using the specific dataset from the National Quality Award Projects where firms tend to be national, which may limit the generalizability of the findings to the whole industry contexts.

While most of the research on market entry practices in the project-based construction industry is undertaken at project or firm level based on survey data, this research represents an exploratory effort of using objective data to provide a macro overview of the practices at the industry level. The findings could contribute to a deepened understanding of how these practices are impacted by related regional- and industry-level factors.

The purpose of this paper was to map the safety management research of construction industry by scientometric analysis, which can predict important highlights and future research directions of safety management research in the construction industry. As an important issue in the construction industry, safety management issues have been researched from different perspectives. Although previous studies make knowledge contributions to the safety management research of construction industry, there are still huge obstacles to distinguish the comprehensive knowledge map of safety management research in the construction industry.

This study applies three scientometric analysis methods, collaboration network analysis, co-occurrence network analysis and cocitation network analysis, to the safety management research of construction industry. 5,406 articles were retrieved from the core collection database of the Web of Science. CiteSpace was used for constructing a comprehensive analysis framework to analyze and visualize the safety management research of construction industry. According to integrating the analysis results, a knowledge map for the safety management research of construction industry can be constructed.

The analysis results revealed the academic communities, key research topics and knowledge body of safety management research in the construction industry. The evolution paths of safety management research in the construction industry were divided into three development stages: “construction safety management”, “multi-objective safety management” and “comprehensive safety management”. Five research directions were predicted on the future safety management research of construction industry, including (1) comprehensive assessment indicators system; (2) intelligent safety management; (3) cross-organization collaboration of safety management; (4) multilevel safety behavior perception and (5) comparative analysis of safety climate.

The findings can reveal the overall status of safety management research in the construction industry and represent a high-quality knowledge body of safety management research in the construction industry that accurately reflects the comprehensive knowledge map on the safety management research of construction industry. The findings also predict important highlights and future research directions of safety management research in the construction industry, which will help researchers in the safety management research of construction industry for future collaboration and work.

Metro wheels running on different lines can undergo wear at different positions. This paper aims to investigate the effects of wheel wear at two typical positions, i.e. wheel flange and tread, on the dynamic performance of metro vehicles and analyzes the differences, with an aim of providing theoretical support on wheel reprofiling for different metro lines.

Wheel profile data were measured on two actual metro lines, denoted A and B. It was observed that wheel wear on Lines A and B was concentrated on flanges and treads, respectively. A metro vehicle dynamics model was built using multibody dynamics software SIMPACK. Then it was applied to analyze the differences in effects of wheel wear at different positions on vehicle dynamic performance (VDP) for various speeds (50, 60 and 70 km/h) and line conditions (straight line, R1000m, R600m and R300m curves). Critical speed and vibration acceleration were used as indicators of VDP during linear motion (on straight track), while VDP during curvilinear motion (on curved track) was evaluated in terms of wheel/rail lateral force, wheel/rail vertical force, derailment coefficient and wheel unloading rate.

First, compared to wheel profile with tread wear, wheel profile with flange wear showed better performance during linear motion. When the distance traveled reached 8 × 104 and 14 × 104 km, the vehicle’s critical speed was 12.2 and 21.6% higher, respectively. The corresponding vertical and lateral vibration accelerations were 59.7 and 74.8% lower. Second, compared to wheel profile with flange wear, that with tread wear showed better performance during curvilinear motion, with smaller wheel/rail lateral force, derailment coefficient and wheel unloading rate. When the vehicle speed was 50, 60 and 70 km/h, the maximum difference in the three indicators between the two wheel profiles was 40.2, 44.7 and 23.1%, respectively. For R1000m, R600m and R300m curves, the corresponding maximum difference was 45.7, 69.0 and 44.4%, respectively.

The results of the study can provide a guidance and theoretical support on wheel reprofiling for different metro lines. On lines with large proportions of curved sections, metro vehicles are more prone to wheel flange wear and have poorer dynamic performance during curvilinear motion. Therefore, more attention should be paid to flange lubrication and maintenance for such lines. On lines with higher proportions of straight sections, metro vehicles are more prone to tread wear and have poorer performance on straight sections. So, tread maintenance and service requires more attention for such lines.

Existing research has focused primarily on the effects of wheel wear on VDP, but fails to consider the differences in the effects of wheel wear at different positions on VDP. In actual metro operation, the position of wheel wear can vary significantly between lines. Based on measured positions of wheel wear, this paper examines the differences in the effects of wheel wear at two typical positions, i.e. tread and flange, on VDP in detail.

This study, a narrative literature review, aims to examine the combined benefits of the active and passive use of social media (SM) for well-being (WB), physical and mental health during the COVID-19 pandemic.

A search strategy has been carried out in the databases: Riss, PubMed, Medline, Scopus and Google Scholar, including all the articles published until 19 October 2023.

SM offers various benefits, including global risk awareness, health information, social connections and support. With the natural increase in physical inactivity due to COVID-19 social restrictions, SM has been identified as an appropriate tool for promoting physical activity (PA) at home to improve health.

It suggests that the combined use of active and passive benefits of SM could potentially play an important role in public health by increasing individuals’ health behaviours. In addition, dissemination, sharing and social interaction of information provided by YouTube can encourage healthy behaviours, contribute to WB, physical and mental health and raise public health awareness.

The findings presented in this study highlight the combined benefits of differentiating the features of SM use. Compared to other SM platforms, YouTube can be used as a useful tool for home-based PA that promotes health by enabling people to remain active and avoid barriers to PA due to social restrictions during the global crisis. In addition, some recommendations from the findings may help protect against potential risks and improve public health outcomes during global crises, such as the COVID-19 pandemic, among the general public using SM.

As the foundation of social and economic development, infrastructure development projects are characterized by large initial investment, high technical requirements and thus generally delivered through complex contractor–subcontractor collaboration chains. This study aims to characterize the complexity of collaborative networks between contractors and subcontractors for infrastructure development through comparing the structural characteristics and the formation mechanisms of contractor–subcontractor collaborative networks for the following two different types of infrastructure: public works (PWCN) owned and operated by government agencies, and public utilities (PUCN) owned and operated by nongovernment agencies.

Based on the method of stochastic actor-oriented models and the longitudinal dataset of National Quality Award Projects in China during 2001–2020, this study compares how the structural characteristics of project-based collaborative networks between contractors and subcontractors for the two types of projects are different and how related micro-mechanisms, including both structure-based endogenous network effects and attribute-based exogenous homophily effects (institutional, organizational and geographical homophily), collectively underpin the formation of the networks.

The empirical results provide evidence that while the two networks are both characterized by relatively low levels of network density, PWCN is more globally connected around a minority of superconnected contractors as compared with PUCN. The results further reveal that compared with PUCN, the formation of PWCN is more significantly related to the structure-based anti in-isolates effect, suggesting that PWCN is more open for new entrant subcontractors. With regard to the attribute-based homophily effects, the results provide evidence that while both significantly and positively related to the effects of organizational (same company group) and geographical homophily (same location), the formation of PWCN and PUCN is oppositely driven by the institutional homophily effect (same ownership type).

As an exploratory effort of using network perspective to investigate the formation mechanisms of contractor–subcontractor relationships in the infrastructure development domain, this study contributes to a network and self-organizing system view of how contractors select subcontractors in different types of infrastructure projects. The study also provides insights into how contractor–subcontractor collaborative relationships can be better manipulated to promote the development of complex infrastructure in different contexts.

The induction of geological disasters is predominantly influenced by the dynamic evolution of the stress and plastic zones of the multilayer rock formations surrounding deep-rock roadways, and the behaviours and mechanisms of high in situ stress are key scientific issues related to deep-resource exploitation. The stress environment of deep resources is more complex owing to the influence of several geological factors, such as tectonic movements and landforms. Therefore, in practical engineering, the in situ stress field is in a complex anisotropic three-dimensional state, which may change the deformation and failure law of the surrounding rock. The purpose of this study is to investigate the tunnelling-induced stress and plastic evolution causing instability of multilayered surrounding rock by varying three-dimensional in situ stresses.

Based on data from the Yangquan Coal Mine, China, a finite difference model was established, and the elastic-plastic constitutive model and element deletion technology designed in the study were analysed. Gradual tunnelling along the roof and floor of the coal seam was used in the model, which predicted the impact tendency, and compared the results with the impact tendency report to verify the validity of the model. The evolutions of the stress field and plastic zone of the coal roadway in different stress fields were studied by modifying the maximum horizontal in situ stress, minimum horizontal in situ stress and lateral pressure coefficient.

The results shown that the in situ stress influenced the stress distribution and plastic zone of the surrounding rock. With an increase in the minimum horizontal in situ stress, the vertical in situ stress release area of the roof surrounding rock slowly decreased; the area of vertical in situ stress concentration area of the deep surrounding rock on roadway sides decreased, increased and decreased by turn; the area of roof now-shear failure area first increased and then decreased. With an increase in the lateral pressure coefficient, the area of the horizontal in situ stress release area of the surrounding rock increased; the area of vertical in situ stress release area of the roof and floor surrounding rock first decreased and then increased; the area of deep stress concentration area of roadway sides decreased; and the plastic area of the surrounding rock and the area of now-shear failure first decreased and then increased.

The results obtained in this study are based on actual cases and reveal the evolution law of the disturbing stress and plastic zone of multilayer surrounding rock caused by three-dimensional in situ stress during the excavation of deep rock roadways, which can provide a practical reference for the extraction of deep resources.

This paper aims to elucidate the geochemical characteristics of the hydrothermally altered rocks with gold mineralization and the elemental transfers in hydrothermal alteration hosted in alkaline complex in Hongshan area, Taihang Orogen, North China, and preliminarily discuss the relationship between the gold mineralization and the hydrothermal alteration.

Based on detailed field investigation, sampling and petrographical observation, major oxides and trace elements of nine rock samples are analyzed, and the method of mass balance equation is used in calculation of the elemental transfer.

Three alteration stages in the Hongshan area are identified, which are the early, main and late alterations. The early one is characteristic of extensive pyritization in the complex, which is related to the mantle-derived magmas and occurs before gold mineralization. The main one is characterized by developing a great deal of altered rock in fracture zones with the gain of many elements and the loss of a few elements. The late one is dominated by limonitization, that is limonite replacing the early pyrite or Fe₂O₃ replacing FeO in rocks. In the main alteration, the altered rocks obviously gain fluid component (LOI, i.e. loss on ignition) and elements such as V, As, Rb, Au, La, Ce and Nd and total rare earth elements (REEs). Elements such as K, Fe, Cu, Zn, Y, Mo, Sb, W, Re and U are gained in some altered rocks. Na and Sr are lost in all altered rocks, and Th and Bi are lost in some ones in the meantime. The following elements: Si, Mg, Mn, Ca, Li, Sc, Cr, Co, Ni, Zr, Ag, Ba and Hg show either gain or loss in different altered rocks. Au is notably enriched in the hydrothermal alteration. The elemental gain or loss in the altered rocks indicates that the main mineralization develops extensive de-alkalinization, local potassic metasomatism, silicification or desilicification.

This paper aims to provide useful information and suggestions for future improvement in relation to China's construction industry and market. With China's rapid economical development and its entry to the World Trade Organization (WTO), much attention has been paid to the China construction business opportunities. However, not much information is available on the history, practices and business cultures of the Chinese construction industry.

Through literature review and interviews with industry professionals, this paper discusses the Chinese construction industry in terms of its market and management practice with a focus on tendering processes, contract management, project on‐site supervision and occupational health and safety (OHS) issues. It also discusses the challenges that face the Chinese construction industry.

China has gone over a long way in construction tendering, contract management and OHS. Its current practice is in the right direction. However, further development and improvements are necessary.

This paper provides useful information to Chinese construction personnel for future improvement. This paper also provides useful information to overseas companies who are planning to enter China's construction market in the near future.

Drawing upon the communicative ecology theory (CET), this study aims to identify the potential precursors of social media health information seeking intentions (ISI) and examine their effects on health information re-sharing behaviors and PHH during coronavirus (COVID-19) pandemic.

The data is collected through an online survey conducted in two different universities situated in highly COVID-19-affected cities – Wuhan and Zhengzhou, China. The valid data consists of 230 useful responses from WeChat users and to analyze the final data set structural equation modeling (SEM) is used.

The results indicate that perceived health information credibility (PIC), trust on the medium (TRM) and peer influence (PI) significantly affect health ISI which further affects health information re-sharing behaviors (IRB) and personal health-care habits (PHH). Besides, the results also identify that PI has a direct, positive and significant effect on health IRB via social media during the COVID-19 pandemic.

This study investigates the health information intentional behavior precursors and their consequences via WeChat (taken as social media platform) during COVID-19 pandemic. Future studies may conduct research by examining online information behaviors on other social media platforms – Twitter, WhatsApp, Facebook, etc. – in health emergency situations.

The health information producers and providers have to deal with communicative ecology sentiments elegantly in emergency situations such as during the COVID-19 pandemic. They need to do collective efforts by introducing new tools or social apps which deal with valuable, reliable and accurate health content and information generated by the pandemic experts and health professionals. In such a way, the social apps and tools (Information providers) will act as mediators between the health professionals (Information producers) and general social media users (information seekers). Such initiatives will ultimately bring forth positive effect on individuals’ PHH as a whole within a network, community, environment or nations during a health emergency – COVID-19 pandemic.

This research is one of the first studies to examine the potential precursors of social media health ISIs and their resultant effects on individual’s health IRB and PHH during the COVID-19 pandemic. As currently it is noticed, an incredible upsurge of health information via social media has intense impacts on personal health-care research and practice, particularly during health emergency situations such as COVID-19 pandemic conditions.