Water treatment public-private partnership (PPP) projects are pivotal for sustainable water management but are often challenged by complex risk factors. Efficient risk management in these projects is ...crucial, yet traditional methodologies often fall short of addressing the dynamic and intricate nature of these risks. Addressing this gap, this comprehensive study introduces an advanced risk classification prediction model tailored for water treatment PPP projects, aimed at enhancing risk management capabilities. The proposed model encompasses an intricate evaluation of crucial risk areas: the natural and ecological environments, socio-economic factors, and engineering entities. It delves into the complex relationships between these risk elements and the overall risk profile of projects. Grounded in a sophisticated ensemble learning framework employing stacking, our model is further refined through a weighted voting mechanism, significantly elevating its predictive accuracy. Rigorous validation using data from the Jiujiang City water environment system project Phase I confirms the model's superiority over standard machine learning models. The development of this model marks a significant stride in risk classification for water treatment PPP projects, offering a powerful tool for enhancing risk management practices. Beyond accurately predicting project risks, this model also aids in developing effective government risk management strategies.
In the last decade, building information modelling (BIM) has emerged as one of the most powerful dynamic decision-making tools throughout a project lifecycle, as its encapsulated information ...synchronises with construction practices. Many reports indicate that BIM has entered the mainstream use in some countries. However, BIM has experienced slow and limited spread adoption in other countries. We propose a comprehensive research model to examine the factors that influence the adoption of BIM. The model draws on technology acceptance model and innovation diffusion theory and is validated using survey data from the construction industry in China. The findings demonstrate that attitude, technological, and organisational dimensions indirectly affect the actual use of BIM through perceived usefulness (PU) and perceived ease of use (PEU), with PU and PEU being the primary determinants of BIM adoption. Furthermore, a striking finding was the positive influence of the attitude dimension on the actual use of BIM.
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•BIM use is prevailing in a few countries, while in others it is slow and difficult.•An integrated TAM-IDT model is developed to explore the hurdle to further use of BIM.•The model was validated using empirical data from the construction industry in China.•The eleven items of three dimensions indirectly affect BIM use through PU and PEU.•The key to a wider adoption of BIM is the transformation of the concepts of users.
Based on the theory of system dynamics, we investigated the factors influencing the trust relationship between owners and PMC contractors in a Chinese management scenario, and proposed effective ...management strategies to increase the level of trust between the two parties. In the early stages of PMC project implementation, calculative trust between the owner and the PMC contractor predominated, while relational trust predominated in the middle and late stages. The applicability of the PMC model and the control configuration between the owner and the PMC contractor are also vital factors influencing the trust level. Principal determinants of calculative trust are the management capability and reputation of the PMC contractor, the sufficiency of the owner’s authorization, and the efficacy of the owner’s supervisory measures. There are four factors that influence relational trust, in order of decreasing influence: the sufficiency of the owner’s authorization, the effectiveness of the owner’s supervisory measures, the social similarity between the owner and PMC contractor, and the management capability and reputation of the PMC contractor. The research can be used as a guide for enhancing PMC project management performance and achieving PMC project success.
The PPP mode of rural water environment governance was conducive to attracting social capital for giving full play to the decisive role of the market in resource allocation, coordinating the ...interests of all parties, and relieving the government budget pressure and debt burden. The cooperation strategy of rural water environment governance PPP projects was analyzed from the perspective of evolutionary game, and dynamic process between project company and farmers was elaborated. First, evolutionary game theory was applied to study the cooperation strategy selection between stakeholders, i.e., the project company and farmers in PPP mode of rural water environment governance project, and evolutionary game model and duplicate dynamic equation were presented for cooperation with project company and farmers, and evolutionary path was obtained. Then four parameters with discount rate of water charges, incentive rate, plant income increasing rate, contribution rate of farmers on the choice of cooperation strategies were simulated. It was indicated that effort strategy of project company and participation strategy of farmers were interrelated from perspective of evolutionary game, and effort strategy of project company was improved discount rate of water charges, incentive rate and plant income increasing rate of farmers, and participation enthusiasm of farmers was improved; thus, engineering quality and efficient operation were assured. As a result, the evolutionary path of cooperation strategy between project company and farmers was suggested as effort strategy and participation strategy, respectively, and corresponding measures of company and participation style of farmers were adopted for promoting the formation of the final equilibrium state.
Benefiting from the rapid developments and wide applications of high-throughput sequencing, great advancements have been made in investigating microbiota, which are highly diverse and play key roles ...in both element cycling and the energy flow of ecosystems. There have been inherent limitations of amplicon sequencing that could introduce uncertainty and raise concerns about the accuracy and reproducibility of this technology. However, studies focusing on the reproducibility of amplicon sequencing are limited, especially in characterizing microbial communities in deep-sea sediments. To evaluate reproducibility, 118 deep-sea sediment samples were used for 16S rRNA gene sequencing in technical replicates (repeated measurements of the same sample) that demonstrate the variability of amplicon sequencing. The average occurrence-based overlaps were 35.98% and 27.02% between two and among three technical replicates, respectively, whereas their abundance-based overlaps reached 84.88% and 83.16%, respectively. Although variations of alpha and beta diversity indices were found between/among technical replicates, alpha diversity indices were similar across samples, and the average beta diversity indices were much smaller for technical replicates than among samples. Moreover, clustering methods (i.e., operational taxonomic units OTUs and amplicon sequence variants ASVs) were shown to have little impact on the alpha and beta diversity patterns of microbial communities. Taken together, although there are variations between/among technical replicates, amplicon sequencing is still a powerful tool with which to reveal diversity patterns of microbiota in deep-sea sediments.
The reproducibility of amplicon sequencing is vital for whether the diversities of microbial communities could be accurately estimated. Thus, reproducibility influences the drawing of sound ecological conclusions. Nevertheless, few studies have focused on the reproducibility of microbial communities that are characterized by amplicon sequencing, and studies focusing on microbiota in deep-sea sediments have been especially lacking. In this study, we evaluated the reproducibility of amplicon sequencing targeting microbiota in deep-sea sediments of cold seep. Our results revealed that there were variations between/among technical replicates and that amplicon sequencing was still a powerful tool with which to characterize the diversities of microbial communities in deep-sea sediments. This study provides valuable guidelines for the reproducibility evaluation of future work in experimental design and interpretation.
The deep sea fuels the world’s largest ecosystem, and a deep knowledge of its relevant evolutionary patterns can support the sustainable development of human society. It is difficult to carry out ...in-situ experiments under the extreme environmental conditions in the deep sea, which puts forward harsh requirements for the development of deep-sea scientific experiment equipment.This study summarizes the development status and problems regarding deep-sea scientific experiment equipment in China and abroad from the aspects of deep-sea test equipment and test sites, deep-sea in-situ exploration and experiment equipment, and experimental equipment for deep-sea environment simulation. China has independently developed a serial of equipment and technologies in the field of deep-sea scientific experiment equipment, and some of its advantageous directions have reached the international advanced level, which has promoted the progress of deep-sea scientific research. However, the country fails to build a mature industrial
Natural gas hydrate (NGH) has been widely focused on having great potential for alternative energy. Numerous studies on gas production from hydrate-bearing sediments have been conducted in both ...laboratory and field. Since the strength of hydrate-bearing sediments depends on the saturation of NGH, the decomposition of NGH may cause the failure of sediments, then leading to reservoir deformation and other geological hazards. Plenty of research has shown that the reservoir deformation caused by hydrate decomposition is considerable. In order to investigate this, the influence of sediment deformation on the production of NGH, a fully coupled thermo-hydro-chemo-mechanical (THMC) model is established in this study. The interaction effects between reservoir deformation and hydrate dissociation are discussed by comparing the simulation results of the mechanical coupling and uncoupled models on the laboratory scale. Results show that obvious differences in behaviors between gas and water production are observed among these two models. Compared to the mechanical uncoupled model, the mechanical coupling model shows a significant compaction process when given a load equal to the initial pore pressure, which leads to a remarkable decrease of effective porosity and reservoir permeability, then delays the pore pressure drop rate and reduces the maximum gas production rate. It takes a longer time for gas production in the mechanical coupling model. Since the reservoir temperature is impacted by the comprehensive effects of the heat transfer from the boundary and the heat consumption of hydrate decomposition, the reduced maximum gas production rate and extended gas production process for the mechanical coupling model lead to the minimum reservoir temperature in the mechanical coupling model larger than that of the mechanical uncoupled model. The reduction of the effective porosity for the mechanical coupling model causes a larger cumulative water production. The results of this paper indicate that the reservoir deformation in the gas production process should be taken into account by laboratory and numerical methods to accurately predict the behaviors of gas production on the field scale.
As a typical unconventional energy reservoir, natural gas hydrate is believed to be the most promising alternative for conventional resources in future energy patterns. The exploitation process of ...natural gas hydrate comprises a hydrate phase state, heat and mass transfer, and multi-phase seepage. Therefore, the study of heat transfer characteristics of gas hydrate is of great significance for an efficient exploitation of gas hydrate. In this paper, the research methods and research progress of gas hydrate heat transfer are reviewed from four aspects: measurement methods of heat transfer characteristics, influencing factors of heat transfer in a hydrate system and hydrate-containing porous media systems, predictive models for effective thermal conductivity, and heat transfer mechanisms of hydrate. Advanced measurement techniques and theoretical methods that can be adopted for the heat transfer characteristics of gas hydrate in the future are discussed.
In implementing the PMC model, trusting relationships between owners and PMC contractors is the key to resolving the dilemmas caused by institutional constraints and conventional thinking, such as ...frequent organizational conflicts, low management efficiency, and higher transaction costs. This study utilized PMC projects in Guangxi, Jiangsu, Zhejiang, Tibet, and Guizhou as analysis samples and employed semi-structured field interviews to investigate the antecedents of trust between owners and PMC contractors. In addition, questionnaires were used to quantify the mechanism of trust formation between the two parties and the influence of trust on project performance. The findings indicated that the managerial competence and reputation of the PMC contractor, the adequacy of the owner's authorization, and the effectiveness of the owner's supervisory measures were the key drivers of calculative trust. The adequacy of the owner's authorization, the effectiveness of the owner's supervisory measures, and social similarity play the greatest roles in influencing relational trust. Calculative and relational trust significantly impact project performance, with relational trust having a slightly more substantial impact. This study can serve as a resource for enhancing the performance of PMC projects and achieving PMC project success.
In Public–Private Partnership (PPP) projects, the structure of the Special Purpose Vehicle (SPV) significantly impacts the value enhancement of projects. This study conducted a quantitative analysis ...of value enhancement in green PPP projects under single- and Dual-Role entity models and examined existing SPV private party compositions. A quantitative model was developed to enhance the value in green PPP projects through a Dual-Role “investor–builder” entity approach, comparing it with the single-role entity model. The findings indicate that in the Dual-Role entity mode, the construction party demonstrates a greater willingness to effort, resulting in shorter construction timelines and improved economic benefits for the project company. The preferred equity range for private parties escalates with the total project investment and the extent of “political support”. Nevertheless, a disproportionately high government stake in the equity is detrimental to the value enhancement in PPPs, and excessive government regulation and control should be avoided. This quantitative model serves as a decision-making criterion for selecting the SPV mode and provides an alternative approach for evaluating PPP project performance.
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