Research on Developers’ Green Procurement Behavior Based on the Theory of Planned Behavior

In recent years, environmental problems in the construction industry have become increasingly prominent and need to be improved. The production and use of building materials remain one of the main causes of various eco-environmental problems in the construction industry. Compared with traditional building materials, green building materials are environmentally friendly and safer to the human body. Therefore, the promotion of green building materials in the construction industry can handle the eco-environmental problems of the industry to a great extent, and promote the green and low-carbon development of the industry. As the main buyer of building materials products, developers shoulder the responsibility of promoting the development of green building materials. The research on the green purchasing behavior of developers is conductive to winning a good reputation for developers and promoting the sustainable development of the construction industry. However, few scholars have focused on the in-depth research on the impact of developers’ green procurement behavior. Based on the theory of planned behavior, this study analyzes the problem of the developers’ green procurement using the structural equation model in the way of the questionnaire. The results showed that subjective norms and perceived behavior control factors exerted a significant influence on developers’ green procurement (GP) behavior attitude. The subjective norm, perceived behavior control, and other factors indirectly affected developers’ GP behavior through behavior intention. The influence mechanism of perceptual behavior control on developers’ GP behavior is more complicated, and the degree of influence is the greatest among the three kinds of factors. According to the research results, this paper puts forward some suggestions to promote developers to actively implement GP behavior. The results help to promote the GP behavior of developers and promote the planning development of green buildings. In addition, on the basis of a quantitative theoretical model, this paper finds out the key factors that influence the behavior of GP from the point of view of developers, enriches the theory and method of GP research, as well as complements the related literature of GP research. Future research will explore GP behavior from the perspective of other stakeholders and from the developers’ internal level

Analysis of Mechanical Parameters and Creep Characteristics of Surrounding Rock in Fully Weathered Sandstone Tunnel

Based on the geological conditions of the fully weathered sandstone stratum in the expressway of the mountainous area, the Huizhou-Qingyuan section of the Yuzhan Expressway is used to analyze the mechanical parameters and creep characteristics of the surrounding rock of the tunnel through the indoor model test. It is concluded that: 1) The uniaxial compression deformation test measured the structural parameters of the fully weathered sandstone stratum structure, and obtained that the elastic modulus and internal friction angle φ of the fully weathered sandstone was 14.20°, and the cohesion c was 0.343Mpa. 2) The failure mode of fully weathered sandstone specimens was obtained by triaxial creep test. The creep curves of different weathered loads were analyzed and the Xiyuan rheological model was established. 3) The creep data was analyzed by MATLAB software, and the surrounding rock parameters under different surrounding rock were obtained

Study on instability failure mode and monitoring early warning standard of surrounding rock in fully weathered argillaceous sandstone section of large section tunnel

Based on the special geological conditions of a tunnel in Qingyuan section of Huizhou-Zhanzhou Expressway, FLAC3d numerical simulation software is used to simulate the rheological properties and instability of surrounding rock in large-section fully weathered sandstone section, and the stability and loss of surrounding rock are analyzed. The deformation of the dome and the face at steady state is analyzed. It is found that: 1) when the surrounding rock is in a stable state, the deformation curve of the dome is smooth. When the surrounding rock of the face is unstable, the front of the face appears ahead. Deformation should be first strengthened on the surrounding rock in front of the face. 2) The arched foot is an important part of the instability of the surrounding rock. In order to prevent the expansion of the collapsed part, the arched part should be reinforced. 3) In order to obtain the limit state of surrounding rock stability, the strength of surrounding rock is reduced, and the strength reduction coefficient corresponding to the displacement sudden point is taken as the safety factor of rock stability around the hole, and the stability safety coefficients of surrounding rock of each construction step are greater than 1.2. 4) The dynamic standard values of deformation control in the whole construction stage are obtained by analyzing the deformation curves of each data monitoring point with time in the corresponding time period of each construction step

Developing A Case-Based Reasoning Model for Safety Accident Pre-Control and Decision Making in the Construction Industry

Case-based reasoning (CBR) has been extensively employed in various construction management areas, involving construction cost prediction, duration estimation, risk management, tendering, bidding and procurement. However, there has been a dearth of research integrating CBR with construction safety management for preventing safety accidents. This paper proposes a CBR model which focuses on case retrieval and reuse to provide safety solutions for new problems. It begins with the identification of case problem attribute and solution attribute, the state of hazard is used to describe the problem attribute based on principles of people’s unsafe behavior and objective’s unsafe state. Frame-based knowledge representation method is adopted to establish the case database from dimensions of slot, facet and facet’s value. Besides, cloud graph method is introduced to determine the attribute weight through analyzing the numerical characteristics of expectation value, entropy value and hyper entropy value. Next, thesaurus method is employed to calculate the similarity between cases including word level similarity and sentence level similarity. Principles and procedures have been provided on case revise and case retain. Finally, a real-world case is conducted to illustrate the applicability and effectiveness of the proposed model. Considering the high potential for pre-control and decision-making of construction safety accident, the proposed model is expected to contribute safety managers to take decisions on prevention measures more efficiently

Control of Gradient Concentration Prussian White Cathodes for High-Performance Potassium-Ion Batteries

Owing to their abundant resources and low cost, potassium-ion batteries (PIBs) have become a promising alternative to lithium-ion batteries (LIBs). However, the larger ionic radius and higher mass of K+ propose a challenging issue for finding suitable cathode materials. Prussian whites (PWs) have a rigid open framework and affordable synthesis method, but they suffer quick capacity fade due to lattice volume change and structural instability during K+ insertion/extraction. Here, we prepared controllable gradient concentration KxFeaNibMn1–a–b[Fe(CN)6]y·zH2O particles via a facile coprecipitation process, demonstrating high-performance potassium-ion storage. The high-Mn content in the interior can minimize capacity loss caused by electrochemically inert Ni and achieve a high reversible capacity; meanwhile, the high-FeNi content in the exterior can alleviate the volume change of the core material upon cycling, thus enhancing structural stability. Taking the above synergistic effect, the controllable gradient concentration PWs deliver a high reversible capacity of 109.8 mAh g–1 at 100 mA g–1 and good capacity retention of 77.8% after 200 cycles. The gradient concentration PWs can retain structural integrity and stability during long-term cycling. This work provides a prospective strategy to fabricate PWs with stable structure and excellent electrochemical performance for developing high-performance PIBs

Fabrication of Conjugated Amphiphilic Triblock Copolymer for Drug Delivery and Fluorescence Cell Imaging

An elegant integration of light-emitting segments into the structure of polymeric delivery systems endows the resulting self-assembled nanovehicles with the diagnostic ability toward an enhanced therapeutic efficiency. A variety of polyfluorene (PF)-based binary delivery systems were designed and developed successfully, but PF-based ternary formulations remain rarely explored, likely due to the synthetic challenge. To develop a universal synthesis strategy toward linear conjugated amphiphilic triblock copolymer for cancer theranostics, herein we focused on the functionalization of the PF terminus for further chain extension and prepared well-defined PF-based amphiphilic triblock copolymers, PF-<i>b</i>-poly­(ε-caprolactone)-<i>b</i>-poly­(oligo­(ethylene glycol) monomethyl ether methacrylate) (PF-<i>b</i>-PCL-<i>b</i>-POEGMA), by integrated state-of-the-art polymer chemistry techniques, including Suzuki reaction, ring-opening polymerization, atom transfer radical polymerization, and click coupling. The resulting conjugated amphiphilic triblock copolymers can self-assembe into core–shell-corona (CSC) micelles with PF block constructing the inner hydrophobic core for fluorescent tracking, PCL segment forming the hydrophobic middle shell for drug encapsulation, and POEGMA moiety building the hydrophilic outer corona for particulate stabilization. Interestingly, the CSC micelles with hydrophobic PCL middle layer show a greater drug loading capacity as well as a higher fluorescence quantum yield (Φ) relative to the core–shell micelles self-assembled from the control of PF-<i>b</i>-POEGMA diblock copolymers without PCL sequence due to having more hydrophobic spaces and better separation of PF sequence provided simultaneously by the PCL central block. The efficient cellular uptake of the anticancer drug doxorubicin-loaded CSC micelles together with the in vitro cytotoxicity against the HeLa cells makes the conjugated amphiphilic triblock copolymers developed herein a promising platform for simultaneous cell image and drug delivery, thus offering great potential for cancer theranostics

Shape-recovery of implanted shape-memory devices remotely triggered via image-guided ultrasound heating.

Shape-memory materials hold great potential to impart medical devices with functionalities useful during implantation, locomotion, drug delivery, and removal. However, their clinical translation is limited by a lack of non-invasive and precise methods to trigger and control the shape recovery, especially for devices implanted in deep tissues. In this study, the application of image-guided high-intensity focused ultrasound (HIFU) heating is tested. Magnetic resonance-guided HIFU triggered shape-recovery of a device made of polyurethane urea while monitoring its temperature by magnetic resonance thermometry. Deformation of the polyurethane urea in a live canine bladder (5 cm deep) is achieved with 8 seconds of ultrasound-guided HIFU with millimeter resolution energy focus. Tissue sections show no hyperthermic tissue injury. A conceptual application in ureteral stent shape-recovery reduces removal resistance. In conclusion, image-guided HIFU demonstrates deep energy penetration, safety and speed

Shape-recovery of implanted shape-memory devices remotely triggered via image-guided ultrasound heating

Abstract Shape-memory materials hold great potential to impart medical devices with functionalities useful during implantation, locomotion, drug delivery, and removal. However, their clinical translation is limited by a lack of non-invasive and precise methods to trigger and control the shape recovery, especially for devices implanted in deep tissues. In this study, the application of image-guided high-intensity focused ultrasound (HIFU) heating is tested. Magnetic resonance-guided HIFU triggered shape-recovery of a device made of polyurethane urea while monitoring its temperature by magnetic resonance thermometry. Deformation of the polyurethane urea in a live canine bladder (5 cm deep) is achieved with 8 seconds of ultrasound-guided HIFU with millimeter resolution energy focus. Tissue sections show no hyperthermic tissue injury. A conceptual application in ureteral stent shape-recovery reduces removal resistance. In conclusion, image-guided HIFU demonstrates deep energy penetration, safety and speed