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Your search keyword '"Chen, Yaohan"' showing total 39 results
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39 results on '"Chen, Yaohan"'

30. High-strength, ultra-thin anion exchange membranes with a branched structure toward alkaline membrane fuel cells.

Author

Li, Xiaofeng, Zhang, Bin, Guo, Jing, Chen, Yaohan, Dai, Lei, Zheng, Jifu, Li, Shenghai, and Zhang, Suobo

Abstract

The preparation of self-supporting anion exchange membranes with enhanced mechanical strength and ultrathin thickness is still a challenge to improve the performance of fuel cells. In this work, we developed 9-dodecylidene-9H-fluorene (DDF) as a branched monomer to construct branched structures based on poly(arylene piperidinium)s. After introducing a 2.5% molar ratio of DDF, quaternized poly(piperidinium-triphenyl-dodecylidenefluorene) (PPTDF-QA) possesses low water swelling (below 25% at 80 °C) and high mechanical strength (over 70 MPa). The obvious phase-separation behavior of the branched membranes induced by the long alkyl chain improves hydroxide conductivity which reaches 168 mS cm−1 at 80 °C. Meanwhile, the thickness of branched PPTDF-QA can be optimized to 8 μm. The present work reveals that a facile branched monomer can promote the formation of a microphase-separated morphology of the membrane to fabricate high-performance anion exchange membranes. [ABSTRACT FROM AUTHOR]

Published
2023
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35. Measurement of smoke generation rate using a full-scale hot smoke test for building smoke exhaust systems

Author

Su, ChungHwei, Wang, ShiuanCheng, Chen, YaoHan, and Wu, CheYi

Abstract

AbstractIn some countries, test standards have been adopted which measure the effectiveness of smoke exhaust systems in clearing out heat and smoke produced separately. However, because these standards provide no quantitative provisions for dealing with the amount of visual smoke, there is an unclear correlation between the amount of smoke generated and the fire load. This paper applied the homogeneity concept of using a smoke collection box to examine the smoke generation rate of a smoke generator using CO2 as the driving gas. To avoid using the previous visual method of judging the rates, this research used measurement equipment to conduct a scientific analysis. Thus, the results were more objective. The equipment used included a Closed-Circuit Television (CCTV) Camera, a thermocouple, a traditional P-type smoke detector, a digital R-type smoke detector, and light attenuation measurement equipment. Under release pressures of 40, 60 and 80 psi, a 15% smoke density required smoke generation at 6.50, 8.42 and 10.46 m3/s, respectively. Achieving a homogeneous distribution of smoke within the space was accomplished. The data obtained in the test could be used not only to judge the efficiency of a smoke exhaust system but also provide adjustment information for a smoke exhaust system.

Published
2022
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37. Performance verification and enhancement of mechanical smoke exhaust system in full-scale hot smoke test for a large space.

Author

Su, ChungHwei, Wang, ShiuanCheng, Chien, ShenWen, and Chen, YaoHan

Subjects
EXHAUST systems, SMOKE, MARITIME museums, FIRE prevention, ATTENUATION of light, PERFORMANCE-based design
Abstract

Full-scale hot smoke test standards have been issued in a number of countries, but the common method of judgment is a visual determination. As Marine Museum K has used a performance-based fire safety design and a numerical simulation during its design stage, this study employs instruments to measure and obtain quantitative comparisons, while enhancing the performance of the smoke exhaust system in different vent-opening modes. The results prove that the measured performance is consistent with the simulation results. The existing model observed that light attenuation is slight at less than 2%, 6% and 10% on the third, fifth and seventh floors, respectively. The effects of the open state of the front and rear vents on the first floor and the vent on the third floor are also discussed. The open mode of the upper and lower vents in Case 2 created a better performance than the other cases due to the excellent flow pattern. In Cases 3 and 4, the fire plumes were significantly disturbed by makeup-air through the vents on the lower floor after all fans were actuated, and the smoke diffused everywhere in the lower floors. This paper also found the disadvantages caused by the makeup air. [ABSTRACT FROM AUTHOR]

Published
2021
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