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As China transitions into a deeply aging society, the elderly population's growth has driven a rapid increase in elderly care institutions and facilities during the "13th Five-Year Plan" period, rising by over 235% compared to the "12th Five-Year Plan". The ongoing normalization of COVID-19 prevention measures has underscored the urgent need to improve natural ventilation in elderly care residential facilities. This study conducted empirical surveys to assess the current state of natural ventilation in typical elderly care facilities and analyzed the architectural elements influencing it. By examining the needs and preferences of the elderly for natural ventilation, two basic living space layout types were identified through typological analysis. Suitable CFD simulation software was then employed to model key elements, and effective methods to enhance ventilation were summarized. This study found that modifying the floor plan to reduce the depth of south-facing rooms to 8.4 m, relocating external openings to the center of the rooms, adjusting the ratio of ventilation openings to room area to greater than 1/12, and adding 0.5 m high windows facing internal traffic roads can significantly improve indoor ventilation while maintaining privacy. Furthermore, placing the main activity and resting areas of the elderly in well-ventilated zones with minimal drafts can enhance both comfort and ventilation effectiveness. The research provides a scientific basis and methodological guidance for the construction and renovation of elderly care residential facilities. [ABSTRACT FROM AUTHOR]

Aging and urbanization significantly impact the physical and mental well-being of the elderly population. Empirical investigations have highlighted the contribution of the built environment to promoting elderly health. However, there is a need for further exploration of the factors within the built environment that impact the subjective well-being (SWB) of the elderly. To address this, this study selected 50 communities in Guangzhou, where 1403 elderly people were surveyed. Employing the random forest, we have identified contributing factors of the built environment affecting the SWB of the elderly. Meanwhile, we used a prediction model constructed by random forest to predict the SWB level of the elderly. The results indicated that accessibility to parks (positive emotions (PA): 0.822, positive experiences (PE): 0.235), hospitals (PA: 0.680, PE: 0.546), and supermarkets (PA: 0.237, PE: 0.617) significantly contributed to PA and PE. On the other hand, factors such as population density had a significant contribution to negative emotions (NA: 0.431) and negative experiences (NE: 0.194). Based on the prediction results, the spatial distribution of SWB among the elderly can be derived. Overall, our study can provide planning and improvement strategies for built environments that promote SWB among the elderly. [ABSTRACT FROM AUTHOR]

Recently, air quality has become a hot topic due to its profound impact on the quality of the human living environment. This paper selects the tourist city of Dalian as the research object. The concentration and spatial distribution of PM10 and NO2 in the main urban area were analyzed during the peak tourist seasons in summer and winter. Simulations were used to explore the spatial and temporal variation patterns of PM10 and NO2, combining building and road density at different scales to reveal the coupling relationship between individual pollutant components and urban parameters. The results show that the PM10 concentration is high in the center and NO2 is concentrated in the northern district of Dalian City. In an area with a radius of 100 m, the dilution ratio of building density and road density to the concentration of the PM10 pollutants is at least 43%. Still, the concentration of NO2 is only coupled with road density. This study reveals the spatial and temporal variation patterns of PM10 and NO2 in Dalian, and finds the coupling relationship between the two pollutants and building density and road density. This study provides a reference for preventing and controlling air pollution in urban planning. [ABSTRACT FROM AUTHOR]

The transport properties at low density are investigated in the framework of the kinetic theory of gases for five binary mixtures composed of CO2, N2, SF6, and CF4, which are of great interest to the electric power industry and are not available in the literature. The Lennard-Jones (12–6) potentials recommended in the literature are used to model the interactions between like molecules, and the Lorentz–Berthelot combining rules are employed to further describe the unlike interactions. The viscosity, binary diffusion coefficient, and thermal diffusion factor are computed for CO2–SF6, CO2–CF4, N2–SF6, N2–CF4, and SF6–CF4. The experimental data are available for the viscosity and diffusion coefficient of the studied systems over a much limited temperature range, and reasonable agreement is found between the experimental data and our calculated values. The new transport property values of the five binary mixtures are tabulated in the supplementary material , covering a very wide temperature range from 300 to 30 000 K. [ABSTRACT FROM AUTHOR]