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This work aims to develop a new kind of semicrystalline polymer filament and optimize its printing parameters in the fused deposition modeling process. The purpose of this work also includes producing FDM parts with good ductility.

A new kind of semicrystalline filaments composed of long-chain polyamide (PA)1012 was prepared by controlling screw speed and pulling speed carefully. The optimal printing parameters for PA1012 filaments were explored through investigating dimensional accuracy and bonding strength of FDM parts. Furthermore, the mechanical properties of PA1012 specimens were also evaluated by varying nozzle temperatures and raster angles.

It is found that PA1012 filaments can accommodate for FDM process under suitable printing parameters. The print quality and mechanical properties of FDM parts highly depend on nozzle temperature and bed temperature. Even though higher temperatures facilitate stronger interlayer bonding, FDM parts with excellent tensile strength were obtained at a moderate nozzle temperature. Moreover, a bed temperature well above the glass transition temperature of PA1012 can eliminate shrinkage and distortion of FDM parts. As expected, FDM parts prepared with PA1012 filaments exhibit good ductility.

Results in this work demonstrate that the PA1012 filament allows the production of FDM parts with desired mechanical performance. This indicates the potential for overcoming the dependence on amorphous thermoplastics as a feedstock in the FDM technique. This work also provides insight into the effect of materials properties on the mechanical performance of FDM-printed parts.

Since surface runoff clogs stormwater grates, leading to deterioration of drainage capacity, and also it is difficult to complete the study with actual dimensions in experiments, a numerical simulation work was established in this study to investigate the surface runoff clogging stormwater grate patterns. The purpose of this study is to describe the mechanisms of storm grate clogging and storm well deposition for different flow rate floods and granular materials.

In the work of this study, the volume of fluid (VOF) method and the discrete element method (DEM) are used to solve the gas–liquid and particle flows. In order to solve the evolution of the gas–liquid interface during surface runoff, the VOF was used. To simulate the rain grate and set up different material particles to represent the surface floating materials, the DEM was utilized.

The research results show that the clogging distribution and clogging rate of the rainwater grate are closely related to the fluid flow velocity and the physical characteristics of the particles, and the higher the clogging rate of the rainwater grate and the higher the number of particles deposited in the rainwater well at the same surface runoff velocity, the higher the density of the clogged particles. The surface runoff velocity (0.5 m/s, 1 m/s) shows that the rapid change of particle movement state at high runoff velocity makes the particle clogging more obvious.

A multi-scale CFD-DEM approach was used to simulate the particulate motion of the road surface with different incoming runoff velocities. The innovative use of DEM to model the storm grate simulation ensures the accuracy of the traction model.

On the basis of Viscoelasticity Theory of textile materials, the Maxwell's Model, Kalvin Paunting Model and Burger's model were analyzed in the paper. The regression equation of the strain relaxation curve was established and the experiments verify that the crease recovery angle can be predicted by the regression equation of Burger's model. The relaxation behavior of crease recovery angle varying with time was according to the creep‐relaxation equation.

The purpose of this paper is to focus on tracing GHG emissions across the supply chain industries associated with the US residential, commercial and industrial building stock and provides optimized GHG reduction policy plans for sustainable development.

A two-step hierarchical approach is developed. First, Economic Input-Output-based Life Cycle Assessment (EIO-LCA) is utilized to quantify the GHG emissions associated with the US residential, commercial and industrial building stock. Second, a mixed integer linear programming (MILP) based optimization framework is developed to identify the optimal GHG emissions’ reduction (percent) for each industry across the supply chain network of the US economy.

The results indicated that “ready-mix concrete manufacturing”, “electric power generation, transmission and distribution” and “lighting fixture manufacturing” sectors were found to be the main culprits in the GHG emissions’ stock. Additionally, the majorly responsible industries in the supply chains of each building construction categories were also highlighted as the hot-spots in the supply chains with respect to the GHG emission reduction (percent) requirements.

The decision making in terms of construction-related expenses and energy use options have considerable impacts across the supply chains. Therefore, regulations and actions should be re-organized around the systematic understanding considering the principles of “circular economy” within the context of sustainable development.

Although the literature is abundant with works that address quantifying environmental impacts of building structures, environmental life cycle impact-based optimization methods are scarce. This paper successfully fills this gap by integrating EIO-LCA and MILP frameworks to identify the most pollutant industries in the supply chains of building structures.

This study examines the stock market efficiency in China to offer trading strategy guidance to investors and efficiency evaluation insight to policymakers.

This study examines the stock market efficiency in China with a new combined liquidity trading strategy by blending technical analysis into a liquidity buy-and-hold strategy.

Our results show that the combined strategy generates significant excess returns in the whole sample period, suggesting that the Chinese stock market is not consistent with the weak form efficient hypothesis. In addition, the combined strategy yields more significant risk-adjusted excess returns after the 2004 split-share reform, indicating the stock market efficiency in China does not exhibit a distinct upgrade after the reform. Our further test results reinforce the main conclusions after taking transaction costs, market states, short-selling reform and other issues into consideration.

Our study contributes to the literature in two ways: First, we shed light on the mixed documented results about the market efficiency form in China. Second, we contribute to the mixed relation between the 2004 split-share reform and market efficiency in China.

This paper examines the gender patterns of occupational mobility in post-reform urban China using a national representative dataset. The results show there are marked gender differences in both direction and self-reported cause of occupational mobility. With respect to the direction of mobility, married women are more likely than married men to undergo downward occupational changes, but are less likely to experience upward moves. In terms of the cause of mobility, compared to married men, married women are less likely to change jobs for career development or move to a new job assigned by the employer, but are more likely to change jobs for family reasons or as a result of involuntary separation. The results also show that the public-sector restructuring has increased the incidence of downward occupational mobility, more for women than men. The analysis suggests that women are disadvantaged in the occupational mobility process by a variety of social and institutional factors.

The thriving global tourism industry is a pivotal player in the global economy. It significantly contributes to a substantial carbon footprint through emissions from transportation, lodging, and infrastructure. In this study we have conducted a critical analysis of carbon emissions within the tourism industry using previous academic literature and institutional databases. Addressing the importance of measuring carbon footprints, the study delves into the definition of the carbon footprint in this sector, emphasizing the urgent need to comprehend and address its effects. This investigation also centers on the aspect of transportation, which is contributing to carbon emissions in the tourism industry. It explores variations based on transportation modes and discusses mitigation strategies, such as green transit. It also concentrates on accommodation, scrutinizing its environmental impact by evaluating carbon emissions from energy consumption, water usage, and waste generation in hotels and resorts. Emphasis is placed on promoting sustainable and green lodging facilities. Furthermore, this study examines the environmental impact of the tourism industry. Specifically, it examines the carbon footprint associated with infrastructure development. The analysis includes the impact of construction and development, resource consumption, and the role of communities and stakeholders in sustainable tourism planning. Furthermore, an assessment is conducted to examine the obstacles associated with adopting sustainable practices and assess the effectiveness of implemented mitigation strategies within the tourism industry. The concluding section outlines future perspectives and recommendations for research.

The type 120 emergency valve is an essential braking component of railway freight trains, but corresponding diaphragms consisting of natural rubber (NR) and chloroprene rubber (CR) exhibit insufficient aging resistance and low-temperature resistance, respectively. In order to develop type 120 emergency valve rubber diaphragms with long-life and high-performance, low-temperatureresistant CR and NR were processed.

The physical properties of the low-temperature-resistant CR and NR were tested by low-temperature stretching, dynamic mechanical analysis, differential scanning calorimetry and thermogravimetric analysis. Single-valve and single-vehicle tests of type 120 emergency valves were carried out for emergency diaphragms consisting of NR and CR.

The low-temperature-resistant CR and NR exhibited excellent physical properties. The elasticity and low-temperature resistance of NR were superior to those of CR, whereas the mechanical properties of the two rubbers were similar in the temperature range of 0 °C–150 °C. The NR and CR emergency diaphragms met the requirements of the single-valve test. In the low-temperature single-vehicle test, only the low-temperature sensitivity test of the NR emergency diaphragm met the requirements.

The innovation of this study is that it provides valuable data and experience for future development of type 120 valve rubber diaphragms.

Epoxy (EP) and polye-caprolactone (PCL) are typical dual-shape memory polymer (DSMP). To get excellent triple-shape memory effect (TSME) polymer composites which are made from EP and PCL. Miscible PCL/EP blend composites have been investigated and compared to the TSMEs with electrospun PCL microfiber membranes/EP composites. Clay montmorillonite (MMT)-modified electrospun PCL microfiber membranes were prepared to improve the shape memory fixities of electrospun PCL microfiber membranes/EP composites.

The morphologies of electrospun PCL microfiber membranes and the cross section of PCL/EP composites were studied using a field emission scanning electron microscope (FE-SEM), and the existence of MMT was confirmed by a transmission electron microscope. Thermal mechanical properties were observed by a differential scanning calorimeter (DSC) and a dynamic thermomechanical analysis machine, and the TSMEs were also determined through dynamic mechanical analysis.

Results indicate that the TSMEs of electrospun PCL microfiber membranes/EP composites were excellent, whereas the TSMEs of PCL/EP blend composites were poor. The TSMEs of PCL electrospun microfiber membranes/EP composites significantly improved with the addition of the PCL electrospun microfiber modified with moderate MMT.

Adding a moderate content of MMT into the electrospun PCL fibers, could improve the TSME of the PCL fiber membranes/EP composites. This study was to create a simple and effective method that can be applied to improve the performance of other SMP.

A novel triple-shape memory composite were made from dual-shape memory EP and electrospun PCL fiber membranes.