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Research on Fire Extinguishing Shell Material Selection and Parameters Optimization
Guan Xiangyi,Liu Shaogang,Sun Qingli,Ma Bingpeng,Zhao Lili 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.5
Remote grenade is often used to fight. Fire extinguishing shell material selection and structure parameters have a great influence on fire extinguishing dispersion and even directly determine the extinguishing effect. Taking the crown fire of Mongolica 20 years old as example, the influences of fire extinguishing bombs with different shell materials on fire extinguishing dispersion are compared in this paper. Simulation of fire extinguishing bombs with different shell materials is operated by finite elements software and come to a conclusion that unidirectional short fiber reinforced composite materials is suitable for fire extinguishing bomb shell because of less power consumption and longer dispersion distance when shell bursting. In the meantime, the experiment is carried out on the sample of fire extinguishing bomb with the shell of unidirectional short fibers. The conclusion is length-diameter ratio to put plant crown fire out has better fire control effect than fire extinguishing bomb with 1.5% powder and save the use of extinguishant.
Preparation and antimicrobial assay of ceramic brackets coated with TiO₂ thin films
Shuai Cao,Ye Wang,Lin Cao,Yu Wang,Bingpeng Lin,Wei Lan,Baocheng Cao 대한치과교정학회 2016 대한치과교정학회지 Vol.46 No.3
Objective: Different methods have been utilized to prevent enamel demineralization and other complications during orthodontic treatment. However, none of these methods can offer long-lasting and effective prevention of orthodontic complications or interventions after complications occur. Considering the photocatalytic effect of TiO₂ on organic compounds, we hoped to synthesize a novel bracket with a TiO₂ thin film to develop a photocatalytic antimicrobial effect. Methods: The sol-gel dip coating method was used to prepare TiO₂ thin films on ceramic bracket surfaces. Twenty groups of samples were composed according to the experimental parameters. Crystalline structure and surface morphology were characterized by X-ray diffraction and scanning electron microscopy, respectively; film thickness was examined with a surface ellipsometer. The photocatalytic properties under ultraviolet (UV) light irradiation were analyzed by evaluating the degradation ratio of methylene blue (MB) at a certain time. Antibacterial activities of selected thin films were also tested against Lactobacillus acidophilus and Candida albicans . Results: Films with 5 coating layers annealed at 700°C showed the greatest photocatalytic activity in terms of MB decomposition under UV light irradiation. TiO₂ thin films with 5 coating layers annealed at 700°C exhibited the greatest antimicrobial activity under UV-A light irradiation. Conclusions: These results provide promising guidance in prevention of demineralization by increasing antimicrobial activities of film coated brackets.