Integrated and effective management of muck waste under the platform governance mode for a circular economy.

As an inevitable part of construction and demolition (C&D) waste, muck has a dreadful environmental impact due its inadequate management by the traditional governance process. This paper therefore focuses on the management of muck generated from C&D waste by utilizing platform governance as an alternative process, which should more effectively contribute to China's circular economy. The study explores the feasibility of providing such a platform governance mode by using Petri net to compare the traditional governance process and platform governance process for the management of muck trucks, and by using Nanjing's muck smart supervision platform as a case study to assess the effectiveness of the platform governance mode. Results from Petri net simulation modeling reveal that the platform governance mode is more effective than the traditional mode, and from the case study it is found that the success of Nanjing's muck waste management can be attributed to the platform governance mode. The platform management approach can therefore contribute to the sustainability of muck waste governance, and is suitable as an integrated and effective management mode for current practices of muck waste management and resource recovery in China. The main finding from the study is that the platform governance mode significantly improves the efficiency of muck waste management as compared with the traditional governance mode and can therefore provide greater economic and environmental benefits as part of a circular economy.

Development of an extended STIRPAT model to assess the driving factors of household carbon dioxide emissions in China.

Although the past twenty years have witnessed China's remarkable economic development, the cost in terms of greenhouse gas emissions and a deteriorating environment has been enormous. Numerous studies have revealed the influence of household factors on household carbon dioxide emissions (HCEs) and called for a reduction of HCEs to mitigate climate change, but few have focused on assessing the most significant household driving factors of HCEs. Using statistical data between 2005 and 2019 in Jiangsu, China, this study developed an extended stochastic impact by regression on population, affluence, and technology (STIRPAT) model to assess the most significant driving factors of HCEs. The results show that the most significant driving factors are household size, total population, unemployment, and urbanisation rate. The study found that HCEs are positively impacted by household size while negatively impacted by the unemployment rate. Based on the study's findings, the following suggestions are proposed to lower HCEs: (i) establish an optimal consumption concept to guide residents towards consuming reasonably; (ii) cultivate a low-carbon concept among residents and promote low-carbon emissions living; and (iii) pay close attention to population structure factors and formulate effective measures accordingly. The study provides insightful information on the key driving factors of HCEs, which can facilitate achieving carbon emissions neutrality.

Realization of maximum optical intrinsic chirality with bilayer polyatomic metasurfaces.

Optical chirality plays a key role in optical biosensing and spin-selective optical field manipulation. However, the maximum optical intrinsic chirality, which is represented by near-unity circular dichroism (CD), is yet to be achieved in a wide bandwidth range based on nanostructures. Here, we utilize dielectric bilayer polyatomic metasurfaces to realize the maximum optical intrinsic chirality over a wide bandwidth range. The CD efficiency of the two designed metasurfaces with opposite chirality is 99.9% at 1350 nm and over 98% from 1340 nm to 1361 nm. Our work provides a straightforward and powerful method for the realization of maximum optical intrinsic chirality, which has great potential in spin-selective optical wave manipulation.

Tunable dual-band and high-quality-factor perfect absorption based on VO2-assisted metasurfaces.

Perfect absorbers with high quality factors (Q-factors) are of great practical significance for optical filtering and sensing. Moreover, tunable multiwavelength absorbers provide a multitude of possibilities for realizing multispectral light intensity manipulation and optical switches. In this study, we demonstrate the use of vanadium dioxide (VO2)-assisted metasurfaces for tunable dual-band and high-quality-factor perfect absorption in the mid-infrared region. In addition, we discuss the potential applications of these metasurfaces in reflective intensity manipulation and optical switching. The Q-factors of the dual-band perfect absorption in the proposed metasurfaces are greater than 1000, which can be attributed to the low radiative loss induced by the guided-mode resonances and low intrinsic loss from the constituent materials. By utilizing the insulator-metal transition in VO2, we further proved that a continuous tuning of the reflectance with a large modulation depth (31.8 dB) can be realized in the designed metasurface accompanied by a dual-channel switching effect. The proposed VO2-assisted metasurfaces have potential applications in dynamic and multifunctional optical devices, such as tunable multiband filters, mid-infrared biochemical sensors, optical switches, and optical modulators.

Investigating the Association between Outdoor Environment and Outdoor Activities for Seniors Living in Old Residential Communities.

Many seniors live in old residential communities (ORCs) with low-quality outdoor environment (OE), which hinders the residents' outdoor daily activities (ODAs). This paper empirically investigates the association of OE on ODAs for seniors living in ORCs. A questionnaire was designed and distributed in six central districts of Nanjing city. A total of 258 questionnaires was finally collected, of which 60.08%, 29.46%, 9.69%, and 0.78% respondents were scattered into four age groups (61-69, 70-79, 80-89, and ≥90), respectively. Based on reliability analysis, correlation analysis, and regression analysis, the results show that: (1) social activities are mainly associated with noise; (2) leisure activities are significantly associated with road accessibility, slip-resistance measures, greenery, and staff; (3) utilitarian-type activities are significantly associated with stairway accessibility, slip-resistance measures, greenery, and seating; (4) there is a significant association between nature-exposure activities and layout, greenery, and poor air quality. The findings could guide Chinese officials when renewing ORCs by addressing the most important outdoor environmental factors associated with ODAs.