Passive daytime radiative cooling (PDRC) is a simple and effective cooling approach that does not consume any extra energy just by highly reflecting shortwave sunlight and highly radiating infrared heat through the atmospheric windows. In recent years, the application of photonic coolers and metamaterials for PDRC has been studied. However, they usually have complex processes and high precision requirements, which seriously limit large-scale fabrication. In this paper, a high-performance polyvinylidene difluoride-hexafluoropropylene (PVDF-HFP) PDRC fiber film was prepared by a simple and efficient electrospinning method combined with phase separation, and the obtained PVDF-HFP fibers have a cauliflower-shaped macro-nanoporous structure. The cauliflower-shaped structure provides more scattering sites of the fibers, and the fiber film with the macro-nanoporous morphology has a high scattering ability in the solar region, resulting in a high solar reflectivity of 99.65%. The PVDF-HFP porous film possesses an emissivity of 90.44% in the atmospheric window, and it can reach a maximum cooling temperature of 10.2 °C during the daytime. In addition, the excellent mechanical strength provides a guarantee for its large-scale practical application. This study offers an effective improvement strategy for the spectral performance of polymer fiber films, which is meaningful for green cooling management and reduction of carbon emission.
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http://dx.doi.org/10.1021/acsami.4c15294 | DOI Listing |
J Appl Gerontol
January 2025
Department of Psychiatry, National Taiwan University Hospital, Taipei, Taiwan.
This study aimed to examine the associations between the different constructs of daytime sleepiness and subjective well-being (SWB), and to investigate whether physical disability moderated these associations in community-dwelling older adults. We examined daytime sleepiness using the Epworth Sleepiness Scale (ESS) and SWB was evaluated in terms of self-rated health and happiness. Exploratory factor analysis (EFA) was used to determine latent constructs of ESS, yielding two primary factors, which were designated as active and passive factors.
View Article and Find Full Text PDFSmall
January 2025
School of Mechanical Engineering, Korea University, 145 Anam-Ro, Seongbuk-Gu, Seoul, 02841, Republic of Korea.
Passive temperature controls like passive daytime radiative cooling (PDRC)-heating (PDRH), and thermal insulation are essential to meet the growing demand for energy-efficient thermal solutions. When combined with advanced functions like electromagnetic interference shielding, these technologies can significantly enhance scalability. However, existing approaches using single thin films or uniform porous materials face inherent limitations in optimizing versatile functions, while lightweight, insulating aerogels can extend their multifunctionality by manipulating pores and fillers.
View Article and Find Full Text PDFArch Public Health
December 2024
Department of Environmental Sciences, Faculty of Natural Resources, University of Guilan, Someh Sara, Guilan, Iran.
Background: This study evaluated the prevalence of sick building syndrome (SBS) in Rasht, Iran, a subtropical climate with wetter cold season city, during the autumn and winter months of 2020, focusing on the effects of noise and ventilation.
Methods: A total of 420 residents completed the indoor air climate questionnaire (MM040EA), and a walk-through survey of 45 randomly selected residential units assessed environmental noise, ventilation rate, and luminous conditions.
Results: Approximately 38.
Int J Biol Macromol
December 2024
Jiangsu Optoelectronic Functional Materials Engineering Research Center, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, China. Electronic address:
Passive radiative cooling (PRC) is an emerging sustainable technology that plays a key role for achieving the goal of carbon neutrality. However, several challenges remain for PRC materials in their practical application in building thermal management, including overcooling problems and unsatisfactory cooling efficiency caused by solar absorption and parasitic heat gains. In this work, fluorinated cellulose-based composite aerogels (FCCA) integrating thermal insulation and PRC were developed by a facile manufacturing strategy that combined phase separation and freeze-drying.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei University, Wuhan 430062, People's Republic of China.
Passive daytime radiative cooling is receiving more and more attention as a cooling method that does not consume energy to cool objects. However, most radiative cooling materials require the mixing of multiple particles, which increases the manufacturing process requirements. Most radiative cooling materials are susceptible to outdoor abrasion, pollution, and UV exposure, which leads to decreased performance.
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