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789 results on '"Yu, Qingbo"'

37. The Effects of Modified Fly Ash on the Structure and Photocatalytic Performance of G‐C3N4‐based Materials.

Author

Yu, Qingbo, Li, Yuqi, Wang, Qingping, Shi, Naishen, Liu, Fan, and Xu, Zishe

Subjects
*FLY ash, *CALCIUM silicate hydrate, *METHYLENE blue, *POTASSIUM hydroxide, *PHOTOCATALYSTS, *CALCIUM hydroxide
Abstract

Regulating the polymerization of graphitic carbon nitride (g‐C3N4) precursor is regarded as a desirable pathway to boost its photocatalytic activity. However, the current has been seldomly concerned in adjusting the polymerization of g‐C3N4 precursor based on the structural characteristics of fly ash (FA). This study manipulates the polymerization reaction of dicyandiamide through alkali treatment of fly ash (KOH‐FA, CaOH‐FA and NaOH‐FA), yielding three g‐C3N4‐based composite photocatalysts (CaFA‐CN, KFA‐CN, and NaFA‐CN) with varying degrees of polymerization. Compared to the zeolite structures of fly ash treated with potassium hydroxide (KOH) and sodium hydroxide (NaOH), the fly ash treated with calcium hydroxide (Ca(OH)2) developed calcium silicate hydrate, leading to a more complex surface structure. Isotherm adsorption model analysis revealed that Ca(OH)2‐FA's adsorption of methylene blue fits the Freundlich model, indicating uneven distribution of active sites. This unevenness results in an uneven collision probability during the high‐temperature polymerization of dicyandiamide, leading to incomplete polymerization and the formation of the CaFA‐CN catalyst with more amino groups and fewer carbon‐nitrogen heterocycles. This incomplete polymerization enabled CaFA‐CN to achieve a 55.3% degradation efficiency of methylene blue within 60 minutes. The photocatalytic activity of CaFA‐CN is 4.03 times that of the original g‐C3N4 (19.4%). [ABSTRACT FROM AUTHOR]

Published
2024
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38. Simulation of Reactive Fluoropolymer-Based Material Penetrator.

Author

Li, Peiyu, Liu, Zhenyang, Zhang, Jiahao, Guo, Mengmeng, and Yu, Qingbo

Subjects
SIMULATION methods & models, ENGINEERING design, IMPACT response, MANUFACTURING processes, COMPUTER simulation
Abstract

It is very important to solve the numerical simulation of fluoropolymer-based reactive materials in the process of engineering design. Although custom development techniques are rapidly being applied to numerical simulation problems of reactive materials, they are inconvenient for engineering designers to implement. This paper presents several simulation methods for fluoropolymer-based reactive materials that can be implemented on commercial software platforms. Comparative analyses were conducted on the intrusion–explosion simulation based on a segmented simulation, a simulation based on the Lee–Tarver EOS, and a simulation of impact response models based on the MPM-SICR algorithm. Additionally, the similarities between these methods and experiments were compared. The results show that the impact response model simulation method based on the MPM-SICR algorithm has certain advantages in describing the impact detonation characteristics of reactive materials. The research findings can provide design assistance and a reference for the application design and damage assessment of fluoropolymer-based reactive material penetrators. [ABSTRACT FROM AUTHOR]

Published
2024
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39. Experimental and Kinetic Study of Biochar in N-Absorption Reaction of Chemical Looping Ammonia Generation.

Author

Liu, Zhongyuan, Yu, Qingbo, Xie, Huaqing, Gao, Jinchao, and Zhao, Jiatai

Subjects
POROSITY, CHEMICAL reactions, GAS flow, ACTIVATION energy, RATE setting
Abstract

The study conducted isothermal tests for biochar-based N-absorption reaction in Chemical Looping Ammonia Generation to investigate the factors affecting biochar conversion, the kinetic model, and the reaction mechanism. The results show that the N2 gas flows had little effect on biochar conversion. Raising the reaction temperature and the molar ratio of α-Al2O3 to C enhanced the conversion of biochar. When the N2 flow rate was set to 200 mL/min, the reaction temperature to 1600 °C, and the α-Al2O3/C molar ratio to 3:3, the biochar conversion reached its peak at 95.45%. After evaluating several kinetic models, the D1 diffusion model was found to provide the closest match to the biochar conversion. The activation energy decreased from 241.91 kJ/mol at a 1:3 α-Al2O3/C molar ratio to 146.77 kJ/mol at a 3:3 ratio with an increasing α-Al2O3/C molar ratio. The biochar's high specific surface area and abundant pore structure facilitated a rapid reaction between carbon and oxygen on the carbon surface. Additionally, the diffusion of oxygen produced during the decomposition of α-Al2O3 became the limiting factor in the N-absorption reaction. [ABSTRACT FROM AUTHOR]

Published
2024
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