Firstly, the characteristics and present situations of the prefabricated construction supply chain are analyzed; inventory cost models for construction material of every phase order, one-off order, and fractionated order are built based on traditional EOQ model and construction supply chain theory. Next, the order decision is represented in binary numbers 0 and 1, in which 0 stands for "no order" and 1 for "order." The analysis uses the genetic algorithm, sets the objective function, and undergoes testing and assessing the individual fitness function, encoding, decoding, crossover, mutation, and selecting parameter. Moreover, inventory cost of construction supply chain is processed and optimized in Matlab. The research establishes a research paradigm on supply chain management of component manufacturing and materials supply. This study concludes the ordering strategy on construction material, identifies the optimal order points and order batches, and provides recommendations for further research.

It is controversial that the cost of construction 3D printing is lower than the conventional construction in academic field. The reason is that some scholars have confused attributes between construction 3D printing and traditional construction. The cost calculation of construction 3D printing cannot follow the rules in conventional construction because construction 3D printing was identified as both industrial product and construction product. This paper proposed a new approach to cost calculation of construction 3D printing concerning both the properties of industrial and construction product. The cost elements and calculation methods of onsite and offsite 3D printing were discussed and concluded. The comparison of cost composition among conventional construction, onsite construction 3D printing, and offsite construction 3D printing was presented as well. The paper put forward the idea of cost calculation about industrialized construction, and it solved the problems of cost calculation among different construction technologies.

Construction 3D printing technology has been rapidly developed, but in the usual life, there are still many people who have not heard of or used construction 3D printing products, and many people want to buy Construction 3D printing products, but there is no channel. Therefore, through the questionnaire survey of potential customers, from the willingness of potential customers, the influencing factors of construction 3D printing technology product trading platform are analyzed, and the PLD-SEM model is established. The potential customers are analyzed in the 3D printing technology product trading platform, with more attention to factors, including product categories, prices, trading platform customization features, and excellent network capabilities. Finally, the 3D printing technology product trading platform was designed, and the customer management module, construction 3D printing technology product information management module, construction 3D printing technology product retrieval module, and transaction information management were proposed. Building a fully functional 3D printing technology product trading platform that can attract more potential customers provides customers with a channel to understand and purchase 3D printing products and helps solve the current 3D printing technology products difficult to promote and trade problem.

The current thermal measurement of sewage sludge in urban sewage treatment plants is mainly based on the determination method of coal calorific value. The calorific value of a secondary sewage treatment plant in a city was measured by an automatic calorimeter. The high calorific value of the sample is obtained by referring to the calorific value measuring method of coal. The results show that the sludge drying base heat value in the process section is relatively high, basically all above 12kJ/g. The theoretical analysis of the calorific value of the same batch of samples is in good agreement with the measured results.

The sequestration (aging) of petroleum hydrocarbons in soil can have a significant effect on the remediation of contaminated sites, but organic chemicals and how they co-exist can result in different sequestration abilities. In this study, sorption, methanol extraction, and sequestration of single and co-existing benzene, 1,3,5-trimethylbenzene, and naphthalene in soil were investigated to evaluate their sequestration ability in soil and the influence of co-existing organic chemicals. A higher linear adsorption coefficient based on the linear sorption equation (k e) was observed for naphthalene (11.5-25.0) compared with benzene (3.8-3.9) and 1,3,5-trimethylbenzene (2.8-5.6), followed by a lower linear methanol extraction coefficient based on the methanol extraction equation (k m = 0.3) and a higher linear sequestration coefficient based on the linear sequestration equation (k s = 0.7). The coexistence of benzene, 1,3,5-trimethylbenzene, and naphthalene increased the sorption ability of 1,3,5-trimethylbenzene (k e increased from 2.8 in the single system to 5.6 in the mixed system) and naphthalene (k e increased from 11.5 in the single system to 25.0 in the mixed system) due to their larger molecular size and higher molecular polarity; however, this was not observed for benzene (k e ranged from 3.8 to 3.9 in the single and mixed systems). In summary, the coexistence of benzene, 1,3,5trimethylbenzene, and naphthalene does not affect methanol extraction and sequestration ability.

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In recent years, China's economy has developed rapidly, the process of urbanization has progressed steadily, the urban and rural infrastructure has been improving day by day, and people's living standards have been significantly improved. But behind the huge economic achievements are resource consumption and environmental pollution. The economic effect of urban environmental sustainability policy is influenced by both policy attribute and economic development stage. This paper establishes a threshold model including different stages of economic development and different types of policies, and analyses the economic effects of urban environmental sustainability policies. The results show that different types of environmental sustainability policies have different economic effects. The economic effects of livable environmental policies and green economic policies are affected by the stage of urban economic development.

In the context of sustainable development, green supply chain, as a whole-process environmental management model, provides a good implementation path for the development and utilization of prefabricated buildings. However, the green supply chain operation of prefabricated buildings in a complex social network environment involves many risk factors, which seriously affect the realization of the green supply chain management goals. This research first identifies risk factors based on the perspective of stakeholders, and then uses fsQCA to analyze the risk factors in the green supply chain of prefabricated buildings, and identifies four configurations that lead to high risks in the green supply chain of prefabricated buildings. Risk is the main risk that leads to the risk of the green supply chain of prefabricated buildings. The types of core risks involved mainly include externality risks, organizational management risks, and manufacturing risks. This research provides an effective method for evaluating and reducing risks in the green supply chain of prefabricated buildings, and improves the effectiveness and accuracy of risk control by all participants.