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1,101 results on '"Kong, Yuan"'

4. Automated Quantification of Traffic Particulate Emissions via an Image Analysis Pipeline

Author

Ho, Kong Yuan, Lim, Chin Seng, Kattar, Matthena A., Boppana, Bharathi, Yu, Liya, and Ooi, Chin Chun

Subjects
Computer Science - Computers and Society, Computer Science - Computer Vision and Pattern Recognition, Physics - Fluid Dynamics
Abstract

Traffic emissions are known to contribute significantly to air pollution around the world, especially in heavily urbanized cities such as Singapore. It has been previously shown that the particulate pollution along major roadways exhibit strong correlation with increased traffic during peak hours, and that reductions in traffic emissions can lead to better health outcomes. However, in many instances, obtaining proper counts of vehicular traffic remains manual and extremely laborious. This then restricts one's ability to carry out longitudinal monitoring for extended periods, for example, when trying to understand the efficacy of intervention measures such as new traffic regulations (e.g. car-pooling) or for computational modelling. Hence, in this study, we propose and implement an integrated machine learning pipeline that utilizes traffic images to obtain vehicular counts that can be easily integrated with other measurements to facilitate various studies. We verify the utility and accuracy of this pipeline on an open-source dataset of traffic images obtained for a location in Singapore and compare the obtained vehicular counts with collocated particulate measurement data obtained over a 2-week period in 2022. The roadside particulate emission is observed to correlate well with obtained vehicular counts with a correlation coefficient of 0.93, indicating that this method can indeed serve as a quick and effective correlate of particulate emissions.

Published
2022

24. Effect of SLM process parameters on microscopic defects and surface quality of GH3536 superalloy

Author

ZHANG Xuan, DONG Anping, DU Dafan, PAN Yunwei, XIONG Lianghua, KONG Yuan, and SUN Baode

Subjects
selective laser melting, gh3536 superalloy, process parameter, microscopic defects, surface quality, Motor vehicles. Aeronautics. Astronautics, TL1-4050
Abstract

GH3536 superalloy was fabricated using Selective Laser Melting (SLM) to investigate the effect of process parameters including the laser power and scanning speed on the density, microscopic defects and surface quality of GH3536 samples. According to the measurement of density, it can be found that the density of samples increases rapidly when the laser energy density is less than 57.0 J/mm3, the density of samples fluctuates within the range of 8.30 g/cm3-8.35 g/cm3 as the laser energy density increases from 57.0 J/mm3 to 187.0 J/mm3, while the density of samples decreases slightly when the laser energy further increases. The conclusion is that the inadequate or excessive energy input reduces the density of samples. The metallographic observation shows that there are a large number of lack-of-fusion defects when the laser energy is insufficient. However, when the input laser energy is too much, many evenly distributed microcracks and gas pores appear inside of samples, indicating that defects are the main reason for low density of samples. The optimal process parameters of SLM-processed GH3536 alloy are determined by the statistical analysis of spatter particles which might cause irregular defects. Tensile properties of the sample fabricated under 175 W and 700 mm/s are tested at room temperature and the results show that the SLM-ed GH3536 superalloy has good tensile properties at room temperature.

Published
2022
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44. Breaking the Scaling Relationship in C−N Coupling via the Doping Effects for Efficient Urea Electrosynthesis.

Author

Lv, Liyang, Tan, Hao, Kong, Yuan, Tang, Bing, Ji, Qianqian, Liu, Yuying, Wang, Chao, Zhuang, Zechao, Wang, Huijuan, Ge, Min, Fan, Minghui, Wang, Dingsheng, and Yan, Wensheng

Subjects
ELECTROSYNTHESIS, UREA, COUPLING reactions (Chemistry), STANDARD hydrogen electrode, CATALYTIC activity, CARBON dioxide
Abstract

Electrochemical C−N coupling reaction based on carbon dioxide and nitrate have been emerged as a new "green synthetic strategy" for the synthesis of urea, but the catalytic efficiency is seriously restricted by the inherent scaling relations of adsorption energies of the active sites, the improvement of catalytic activity is frequently accompanied by the decrease in selectivity. Herein, a doping engineering strategy was proposed to break the scaling relationship of intermediate binding and minimize the kinetic barrier of C−N coupling. A thus designed SrCo0.39Ru0.61O3−δ catalyst achieves a urea yield rate of 1522 μg h−1 mgcat.−1 and faradic efficiency of 34.1 % at −0.7 V versus reversible hydrogen electrode. A series of characterizations revealed that Co doping not only induces lattice distortion but also creates rich oxygen vacancies (OV) in the SrRuO3. The oxygen vacancies weaken the adsorption of *CO and *NH2 intermediates on the Co and Ru sites respectively, and the strain effects over the Co−Ru dual sites promoting the occurrence of C−N coupling of the two monomers instead of selective hydrogenating to form by‐products. This work presents an insight into molecular coupling reactions towards urea synthesis via the doping engineering on SrRuO3. [ABSTRACT FROM AUTHOR]

Published
2024
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