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Wyszukujesz frazę "Cheng, Ming" wg kryterium: Autor


Wyświetlanie 1-4 z 4
Tytuł:
Prediction of PM2.5 hourly concentrations in Beijing based on machine learning algorithm and ground-based LiDAR
Autorzy:
Fang, Zhiyuan
Yang, Hao
Li, Cheng
Cheng, Liangliang
Zhao, Ming
Xie, Chenbo
Powiązania:
https://bibliotekanauki.pl/articles/2073773.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
PM2.5
LiDAR
machine learning
air pollution monitoring
Opis:
The prediction of PM2.5 is important for environmental forecasting and air pollution control. In this study, four machine learning methods, ground-based LiDAR data and meteorological data were used to predict the ground-level PM2.5 concentrations in Beijing. Among the four methods, the random forest (RF) method was the most effective in predicting ground-level PM2.5 concentrations. Compared with BP neural network, support vector machine (SVM), and various linear fitting methods, the accuracy of the RF method was superior by 10%. The method can describe the spatial and temporal variation in PM2.5 concentrations under different meteorological conditions, with low root mean square error (RMSE) and mean square deviation (MD), and the consistency index (IA) reached 99.69%. Under different weather conditions, the hourly variation in PM2.5 concentrations has a good descriptive ability. In this paper, we analyzed the weights of input variables in the RF method, constructed a pollution case to correspond to the relationship between input variables and PM2.5, and analyzed the sources of pollutants via HYSPLIT backward trajectory. This method can study the interaction between PM2.5 and air pollution variables, and provide new ideas for preventing and forecasting air pollution.
Źródło:
Archives of Environmental Protection; 2021, 47, 3; 98--107
2083-4772
2083-4810
Pojawia się w:
Archives of Environmental Protection
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Flexural Properties of Thin Fly Ash Geopolymers at Elevated Temperature
Autorzy:
Ng, Yong-Sing
Liew, Yun Ming
Heah, Cheng Yong
Abdullah, Mohd Mustafa Al Bakri
Ng, Hui-Teng
Chan, Lynette Wei Ling
Powiązania:
https://bibliotekanauki.pl/articles/2134117.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
thin geopolymer
fly ash
elevated temperature
flexural strength
Opis:
This paper reports on the flexural properties of thin fly ash geopolymers exposed to elevated temperature. The thin fly ash geopolymers (dimension = 160 mm × 40 mm × 10 mm) were synthesised using 12M NaOH solution mixed with designed solids-to-liquids ratio of 1:2.5 and Na2SiO3/NaOH ratio of 1:4 and underwent heat treatment at different elevated temperature (300°C, 600°C, 900°C and 1150°C) after 28 days of curing. Flexural strength test was accessed to compare the flexural properties while X-Ray Diffraction (XRD) analysis was performed to determine the phase transformation of thin geopolymers at elevated temperature. Results showed that application of heat treatment boosted the flexural properties of thin fly ash geopolymers as the flexural strength increased from 6.5 MPa (room temperature) to 16.2 MPa (1150°C). XRD results showed that the presence of crystalline phases of albite and nepheline contributed to the increment in flexural strength.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 3; 1145--1150
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Sodium Aluminate on the Fresh and Hardened Properties of Fly Ash-Based One-Part Geopolymer
Autorzy:
Ooi, Wan-En
Liew, Yun Ming
Heah, Cheng Yong
Ho, Li-Nge
Abdullah, Mohd Mustafa Al Bakri
Ong, Shee-Ween
Sandu, Andrei Victor
Powiązania:
https://bibliotekanauki.pl/articles/2106571.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
geopolymer
one-part geopolymer
fly ash
sodium aluminate
sodium metasilicate
Opis:
The one-part geopolymer binder was synthesis from the mixing of aluminosilicate material with solid alkali activators. The properties of one-part geopolymers vary according to the type and amount of solid alkali activators used. This paper presents the effect of various sodium metasilicate-to-sodium aluminate (NaAlO2/Na2SiO3) ratios on fly ash-based one-part geopolymer. The NaAlO2/Na2SiO3 ratios were set at 1.0 to 3.0. Setting time of fresh one-part geopolymer was examined through Vicat needle apparatus. Mechanical and microstructural properties of developed specimens were analysed after 28 days of curing in ambient condition. The study concluded that an increase in NaAlO2 content delayed the setting time of one-part geopolymer paste. The highest compressive strength was achieved at the NaAlO2/Na2SiO3 ratio of 2.5, which was 33.65 MPa. The microstructural analysis revealed a homogeneous structure at the optimum ratio. While the sodium aluminium silicate hydrate (N-A-S-H) and anorthite phases were detected from the XRD analysis.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 2; 441--445
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Silica Fume and Alumina Addition on the Mechanical and Microstructure of Fly Ash Geopolymer Concrete
Autorzy:
Fong, Sue Min
Heah, Cheng Yong
Liew, Yun Ming
Abdullah, Mohd Mustafa Al Bakri
Hasniyati, Md Razi
Low, Foo Wah
Ng, Hui-Teng
Ng, Yong-Sing
Powiązania:
https://bibliotekanauki.pl/articles/2048824.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
geopolymer
concrete
silica fume
alumina
Opis:
This paper discussed the effect of the addition of silica fume (2 wt.% and 4 wt.%) and alumina (2 wt.% and 4 wt.%) on the properties of fly ash geopolymer concrete. The fly ash geopolymer concrete achieved the highest 28-day compressive strength with 2 wt.% of silica fume (39 MPa) and 4 wt.% of alumina (41 MPa). The addition of 2 wt.% of silica fume increased the compressive strength by 105% with respect to the reference geopolymer (without additive). On the other hand, the compressive strength surged by 115% with 4 wt.% of alumina compared to the reference geopolymer. The addition of additives improved the compactness of the geopolymer matrix according to the morphology analysis.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 1; 197-202
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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