Although integrated project delivery (IPD) is still in its infancy in the construction industry worldwide, some principles can be effective without formal contractual languages and enforcements when IPD is employed as a philosophy as opposed to a delivery method. This paper aims to investigate the effect of IPD principles on project performance in China, providing a reference for improvement of project performance by the application of IPD principles in countries or regions where IPD is considered as a philosophy. A total of 205 data samples were collected from different IPD-related participants in China via a questionnaire survey. Eight hypotheses are proposed based on a literature review, and these are verified using a structural equation model (SEM). According to the results of the exploratory factor analysis, IPD principles, including behavioral principles, contractual principles, collaboration-related principles, and catalysts, are classified, and the internal relationship of various IPD principles is explored using SEM to analyze the impact path between IPD principles and project performance. It was discovered that project performance is directly affected by collaboration-related principles and catalysts. The contractual principles have positive impacts on both behavioral principles and collaboration-related principles, while the catalysts show positive impacts on behavioral principles. This work provides insights and managerial implications for local applications of IPD for construction practitioners, which should be considered by promoting regional IPD practices; it contributes to both theoretical and practical perspectives for improving project performance by the effective implementation of IPD in construction projects.

The construction supply chain has many stakeholders and complex and diverse information, which cause various information exchange problems that diminish project management efficiency. Thus, information collaboration is an important factor in the construction supply chain. This study aims to improve the efficiency of project management by analyzing the factors hindering information collaboration in the construction supply chain in order to determine their internal influencing mechanisms. The relevant data of 281 construction employees is collected by questionnaire survey. The relationship among stakeholders (SH), information technology (IT), external stability mechanism (ESM), and information collaboration is then quantitatively evaluated based on the structural equation model (SEM). The results show that stakeholders, information technology, and the external stability mechanism have an influence on information collaboration, while stakeholders do not have a significant influence. Information technology and the external stability mechanism significantly influence information collaboration and provide a mediation role between stakeholders and information collaboration. The innovation of this work is the quantification of information collaboration influencing factors in the construction supply chain and the analysis of its potential path relationship according to the mediating effect test. Its theoretical contribution is to address the research gap in construction supply chain information collaboration and expand the research scope of construction project collaborative management regarding information collaboration. Finally, this work has a practical contribution by providing suggestions for improving the efficiency of building supply information collaboration.

High temperatures exacerbate the ammonia inhibition of anaerobic digestion coupled with methanogenesis. The inhibition of methane production by ammonia has been observed in other studies. However, the underlying mechanism is not well understood and requires further investigation. This study explored the effect of ammonia stress on archaeal 16S rRNA transcripts in thermophilic anaerobic digester sludge. Different ammonium concentrations were checked for their influence on the methanogenic rate and hydrogen accumulation. Quantitative PCR was used to compare the changes in total archaeal 16S rRNA expression. A Monte Carlo permutation test within redundancy analysis (RDA) was adopted for exploring the relationship between environmental variables and archaeal 16S rRNA and their transcripts. The results showed that with the increase in ammonium concentration, the methanogenic rate decreased and hydrogen accumulation occurred. The total archaeal 16S rRNA genes and transcripts copy numbers decreased significantly in treatments with higher ammonium concentrations (7 and 10 g NH₄⁺-N/L), but did not change much at lower ammonia concentrations (3 g NH₄⁺-N/L) compared with the 0 g NH₄⁺-N/L treatment. The RDA analysis further revealed that most environmental variables, including ammonia and methane, except for formate, were significantly correlated with the community structure activity of archaeal 16S rRNA transcripts rather than the community structure of their genes. The composition of archaeal 16S rRNA transcripts showed that the hydrogenotrophic methanogen Methanothermobacter dominated the methanogenic community activity in all incubations. It exhibited sensitivity to ammonia stress and should be responsible for the methanogenic inhibition under thermophilic conditions. Our findings suggested that archaeal 16S rRNA transcripts, rather than 16S rRNA genes, are key indicators of ammonia stress and methanogenic activity.

This paper explores a novel approach to clarify the applicability of the Integrated Project Delivery (IPD) principles in a certain region or country which has a specific cultural background, the paper further promotes the effective application of IPD principles. The method of combining qualitative and quantitative analysis is adopted, incorporating scientometric analysis, questionnaire survey, qualitative analysis, and a measurement model. On the basis of 310 sample data collected from various practitioners and researchers in China’s construction industry, the measurement models of IPD applicability analysis on the average level of sample (ALS) and the best level of sample (BLS) are established, respectively. The results show that these measurement models are essentially consistent with the composition of the conceptual model, including project performance, contractual principles, collaboration-related principles, behavioral principles, and catalysts. Thus, this paper provides a scientific and methodological basis for how to effectively apply the IPD principles. This study sheds light on project delivery system research in two aspects: it proposes a new idea to study the applicability of IPD principles and lays a foundation for the future quantitative study on the impact mechanism of IPD principles on project performance.