The pyrolysis behavior of polycarbosilane （PCS） and chemical reaction mechanism during the pyrolysis process were studied by thermogravimetric-mass spectrometry （TG-MS） combined with X-ray diffraction and infrared...The pyrolysis behavior of polycarbosilane （PCS） and chemical reaction mechanism during the pyrolysis process were studied by thermogravimetric-mass spectrometry （TG-MS） combined with X-ray diffraction and infrared spectroscopic analysis methods. The experimental results indicate that the main gas phase products generated during pyrolysis of PCS in nitrogen atmosphere include H2, -CH3 and CH4. The heating rate has a large effect on the pyrolysis process of PCS, the lower heating rate releases more small molecule gases and gets bigger rate of pyrolysis mass loss, demonstrating that the lower heating rate is beneficial to fully pyrolysis of PCS and obtain ceramics products with better microstructure.展开更多
Drying characteristics in terms of diffusivity were studied for mushrooms and different vegetables in a fluidized bed dryer. Drying characteristics with falling rate regime were computed for all the sampi^z. Effective...Drying characteristics in terms of diffusivity were studied for mushrooms and different vegetables in a fluidized bed dryer. Drying characteristics with falling rate regime were computed for all the sampi^z. Effective diffusivity of each sample was calculated. Mass transfer coefficients were determined. Mass transfer kinetics for drying of different samples was also found out. Correlations for the diffusivity of samples were developed by relating the experimentally observed data with the different system parame- ters on the basis of regression analysis. The developed correlations for effective moisture diffusivity of the samples are validated by artificial neural network （ANN） modeling. Finally calculated values of diffusivity obtained through both the methods are compared with the experimentally measured values which show a very good approximation thereby indicating the wide applicability of the developed correlations for industrial uses.展开更多
基金Funded by the Natural Science Foundation of Hubei Province(No.2013CFB340)
文摘The pyrolysis behavior of polycarbosilane （PCS） and chemical reaction mechanism during the pyrolysis process were studied by thermogravimetric-mass spectrometry （TG-MS） combined with X-ray diffraction and infrared spectroscopic analysis methods. The experimental results indicate that the main gas phase products generated during pyrolysis of PCS in nitrogen atmosphere include H2, -CH3 and CH4. The heating rate has a large effect on the pyrolysis process of PCS, the lower heating rate releases more small molecule gases and gets bigger rate of pyrolysis mass loss, demonstrating that the lower heating rate is beneficial to fully pyrolysis of PCS and obtain ceramics products with better microstructure.
文摘Drying characteristics in terms of diffusivity were studied for mushrooms and different vegetables in a fluidized bed dryer. Drying characteristics with falling rate regime were computed for all the sampi^z. Effective diffusivity of each sample was calculated. Mass transfer coefficients were determined. Mass transfer kinetics for drying of different samples was also found out. Correlations for the diffusivity of samples were developed by relating the experimentally observed data with the different system parame- ters on the basis of regression analysis. The developed correlations for effective moisture diffusivity of the samples are validated by artificial neural network （ANN） modeling. Finally calculated values of diffusivity obtained through both the methods are compared with the experimentally measured values which show a very good approximation thereby indicating the wide applicability of the developed correlations for industrial uses.
