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Background: Expiratory airflow limitation (EAL) is closely associated with respiratory health in youth and adulthood. Owing to limited evidence, we aim to estimate the association between air pollutants, both individually and in combination, along with their chemical compositions, and the risk of EAL in youth based on data obtained from Northeast China Biobank. Methods: Pulmonary function was evaluated using a medical-grade pulmonary function analyzer, with EAL defined as a forced expiratory flow in 1 s/ forced vital capacity ratio of < 0.8. Land use regression models were used to predict exposure to six air pollutants. Air pollution score (APS) for each participant was constructed as combined exposure. The chemical composition of particulate matter with an aerodynamic diameter of ≤ 2.5 µm (PM2.5) was determined using a validated machine-learning algorithm. Logistic regression models were employed to estimate effect sizes, and odds ratio (OR) and 95 % confidence intervals (CI) were calculated. Results: In total, 905 EAL cases were identified among the 4301 participants, with a prevalence of 21.04 %. Each inter-quartile range increase in APS was associated with a 25 % higher risk of EAL (OR = 1.25, 95 % CI: 1.12, 1.39). Among the pollutants analyzed, PM2.5 exposure had the strongest association with the risk of EAL (OR = 1.33, 95 % CI: 1.18, 1.52). Out of the five chemical components, sulfate (SO2-4) (OR = 1.39, 95 % CI: 1.24, 1.57) and ammonium (NH+4) (OR = 1.39, 95 % CI: 1.23, 1.57) exhibited the strongest associations with the risk of EAL. Conclusions: Overall, combined effects of air pollution increased the risk of EAL in youth, with SO2-4 and NH+4 emerging as the predominant contributing chemical components in Northeast China.

Many researchers have reported that inter-yarn friction has an important effect on the response of the plain-weave fabric to an impact. However, the effects of inter-yarn friction on impact responses of woven fabrics with other weaves have not been studied in detail. In the present work, numerical analysis was utilized to study the effects of inter-yarn friction on responses of woven fabrics with different weaves (the plain weave, 2/2 twill, 2/2 basket, and 3/1 twill) to a low-velocity impact. Both inter-yarn friction and the weaves of the woven fabrics greatly influenced the responses of the fabrics to a low-velocity impact. The higher the inter-yarn friction, the higher the levels of the tensile stresses concentrated near the centers of impact of the woven fabrics, and the earlier the failures of the fabrics. In addition, the greater the inter-yarn friction, the higher the velocities of the transverse stress waves in the woven fabrics, and the more effective the distributions of impact energy from the primary yarns of the fabrics to the secondary yarns of the fabrics. Although it had the lowest velocity of the transverse stress wave, due to its firmly interlaced yarns, the plain-weave fabric had the highest total energy absorption capacity among the woven fabrics with the different weaves. On the other hand, due to its loosely interlaced yarns, the 3/1 twill fabric had the lowest total energy absorption capacity among the woven fabrics.

The interfacial structure and binding forces of polytrimethylene terephthalate/polyethylene terephthalate filament were investigated through the methods of Carbon-13 nuclear magnetic resonance (13C-NMR), differential scanning calorimeter (DSC), scanning electron microscopy (SEM) and optical microscopy. When two molten polymers met during the spinning process, an interface layer between the PTT and PET components formed and played an important role in binding the two components together. When the blending time was sufficient, an ester-interchange reaction took place with the generation of the copolymer. The PET recrystallisation was observed in the DSC curve under the influence of entangled PTT molecular chains. The morphology of the cross-section and side view proved that the linear boundary line was short and weaker in binding without a chemical bond and molecular diffusion. Side-by-side bi-component fiber and split-type fiber was able to be controllably spun by adjusting the spinning parameters. [ABSTRACT FROM AUTHOR]

To investigate the effect of nanoparticle (NP) concentration on passive cooling performance of zinc oxide (ZnO) spheric NP doped low density polyethylene (LDPE) films for indoor and outdoor spaces, flexible transparent passive-cooling LDPE films doped with uniformly dispersed 4, 5 and 6% of 90 nm ZnO NPs were fabricated by solution-casting method. Scanning electron microscopy, differential scanning calorimetry, ultraviolet-visible-near-infrared spectrophotometry, and in-situ passive cooling tests were performed to study various properties and performances of the films. The results show that the dispersion of the NPs in the composite films was reasonably uniform. The crystallinities of the films were not influenced by the change of the NP concentration. The transmissivities of the films were decreased monotonically in ultraviolet (UV) and high energy range of visible light (Vis), as the NP concentration increased. In the lower energy part of Vis and near infrared (nIR) range, increased NP concentration suppressed the transmissivity of solar irradiation. However, the 5% film had a lower transmissivity in nIR range than the 6% film due to agglomeration of NPs. All composite films showed a strong reflectance to solar irradiation from 19 - 37%. The 6% film had higher reflectance than that of the 5% film, making it a better passive cooling material because of much better NP dispersion. The temperature reduction of the 4% and 5% films were 19 and 21% while that of the 6% film reached 35% in the testing temperature range. This indicates that the NP concentration and their dispersion are both critical for optimization of the passive cooling performance of the composite films. [ABSTRACT FROM AUTHOR]

The airflow field in a fibre transport channel is crucial as it affects the fibre configuration significantly and, consequently, the yarn properties. Geometric parameters are found to be critical in influencing airflow characteristics. 3D finite volume computations were adopted to evaluate the effects of geometric parameters of the transport channel on airflow characteristics. A bypass channel for extra air supply into the transport channel was also evaluated. The results reveal that the transport channel inlet area has a more significant impact on the vortices generated at the channel inlet than the transport channel length. Either increasing the transport channel length or decreasing the transport inlet area can reduce the vortices but cannot eliminate them. By adopting a bypass channel, the vortices are reduced significantly and the air velocity at the transport channel inlet, especially in the fibre separation area, is increased. [ABSTRACT FROM AUTHOR]

Presents a study which used X-ray photoelectron spectroscopy and scanning electron microscope to analyze the effects of atmospheric pressure plasma treatments on desizing of polyvinyl alcohol (PVA) on cotton fabrics. Calculation of the percent desizing ratio of the fabric; Effect of treatment on PVA films; Influence of treatment on fabric and yarn tensile strength.

Presents a study which examined the use of atmospheric pressure plasma treatment in desizing polyvinyl alcohol on viscose fabrics. Experimental procedures; Results and discussion; Conclusion.