Zinc is one of the hazardous metals commonly found in municipal solid waste incineration （MSWI） ash, and this study reveals the stabilization mechanisms when sintering zinc-laden ash and ceramic precursors as a wast...Zinc is one of the hazardous metals commonly found in municipal solid waste incineration （MSWI） ash, and this study reveals the stabilization mechanisms when sintering zinc-laden ash and ceramic precursors as a waste-to-resource strategy. Using ZnO to simulate the zinc-laden ash and sintering with kaolinite and mullite ce- ramic precursors, both zinc aluminate spinel （ZnA1204） and willemite （Zn2SiO4） phases were found in the products under the tested thermal conditions. The results also indicate that kaolinite and mullite precursors exhibit different incorporation behavior, and ZnA1204 and Zn2SiO4 were found to be competitive as the Zn-hosting phases in the system. A prolonged leaching test was used to evaluate the leachability of potential product phases in the system. The concentrations of zinc in ZnO and Zn2SiO4 leachates were about two orders of magnitude higher than that in ZnA1204 leachate, indicating the preference of forming ZnA1204 for zinc stabilization. Furthermore, the alumi- num-rich sludge generated from waterworks could be beneficially used as a material resource to stabilize zinc in this study. The X-ray diffraction （XRD） pattern collected from the 1150 ~C and 3-h sintered sample shows the suc- cess of incorporating zinc into the ZnA1204 spinel structure with waterworks sludge precursor. The formation of ZnA1204 indicates a strong potential for employing aluminum- and silicon-based materials to thermally immobilize zinc and achieve the beneficial use of metal-laden MSWI ash.展开更多
The general behavior of micron-particles in the inner domain of porous ceramic vessel was simulated by computational fluid dynamics software in terms of sampling experimental data.The results show that there is an opt...The general behavior of micron-particles in the inner domain of porous ceramic vessel was simulated by computational fluid dynamics software in terms of sampling experimental data.The results show that there is an optimum porosity of 0.32 to get a higher efficiency and lower pressure drop during filtration.According to the results of simulation and experiment,it is evident that lower inlet velocity can maintain lower pressure drop and obtain higher collection efficiency and inlet concentration also has a crucial influence on the collection efficiency.The collection efficiency of equipment increases significantly with the increase of inlet concentration when the inlet concentration is less than 6.3 g/m3,but it gradually tends to be stable in the range of 97.3%-99.7%when the inlet concentration is over this concentration.展开更多
Hydroxyapatite bioceramics is simulated by using finite element method （FEM）. The influences of porosity, hole shape, angle of crack and other parameters on the ceramics are analyzed. The results show that with the ...Hydroxyapatite bioceramics is simulated by using finite element method （FEM）. The influences of porosity, hole shape, angle of crack and other parameters on the ceramics are analyzed. The results show that with the increase of the angle between crack and horizontal direction, the stress intensity factor KⅠ decreases gradually, but stress intensity factor KⅡ increases at first and then it decreases. The value of KⅡ reaches maximum when the angle between crack and horizontal direction is 45°. KⅠ and KⅡ rise with the increase of porosity, and they are almost the same for the circular and hexagonal holes. For elliptical holes, KⅠ and KⅡ reach maximum when the long axis of ellipse is perpendicular to the loading direction and they reach minimum when the same axis is parallel to the loading direction. Moreover, with the increase of the angle between the long axis and loading direction, KⅠ and KⅡ increase gradually.展开更多
Shapes are important clues for the identification of ancient ceramics.In this study,digital extraction methods of shape characterization were discussed,using samples of flared mouthed porcelain bowls produced in Jingd...Shapes are important clues for the identification of ancient ceramics.In this study,digital extraction methods of shape characterization were discussed,using samples of flared mouthed porcelain bowls produced in Jingdezhen Hutian Kiln from the Five Dynasties to the Song and Yuan period.By employing the techniques of image enhancement,edge detection and curve fitting of Matlab,the method using digital shape characterization has advanced accuracy and effectiveness of traditional identification which is based on visual and tactual inspections.Together with the increasingly applied compositional data analysis and thermoluminescence dating technique,the method will further improve and upgrade the scientific identification system for ancient ceramics.展开更多
Oxygen vacancy, a kind of native point defects in ferroelectric ceramics, usually causes an increase of the dielectric loss. Based on experimental observations, it is believed that all of the oxygen vacancies are an u...Oxygen vacancy, a kind of native point defects in ferroelectric ceramics, usually causes an increase of the dielectric loss. Based on experimental observations, it is believed that all of the oxygen vacancies are an unfavorable factor for energy saving. By using molecular dynamics simulations, we show that the increase of coercive and saturated electric fields is due to the difficulty to switch local polarization near an oxygen vacancy, and so that a ferroelectric device has to sustain the rising consumption of energy. The simulation results also uncover how oxygen vacancies influence ferroelectric properties.展开更多
基金Supported by the General Research Fund Scheme(HKU 716809E,HKU 716310E)Special Equipment Grant(SEG_HKU10) of the Research Grants Council of Hong Kong
文摘Zinc is one of the hazardous metals commonly found in municipal solid waste incineration （MSWI） ash, and this study reveals the stabilization mechanisms when sintering zinc-laden ash and ceramic precursors as a waste-to-resource strategy. Using ZnO to simulate the zinc-laden ash and sintering with kaolinite and mullite ce- ramic precursors, both zinc aluminate spinel （ZnA1204） and willemite （Zn2SiO4） phases were found in the products under the tested thermal conditions. The results also indicate that kaolinite and mullite precursors exhibit different incorporation behavior, and ZnA1204 and Zn2SiO4 were found to be competitive as the Zn-hosting phases in the system. A prolonged leaching test was used to evaluate the leachability of potential product phases in the system. The concentrations of zinc in ZnO and Zn2SiO4 leachates were about two orders of magnitude higher than that in ZnA1204 leachate, indicating the preference of forming ZnA1204 for zinc stabilization. Furthermore, the alumi- num-rich sludge generated from waterworks could be beneficially used as a material resource to stabilize zinc in this study. The X-ray diffraction （XRD） pattern collected from the 1150 ~C and 3-h sintered sample shows the suc- cess of incorporating zinc into the ZnA1204 spinel structure with waterworks sludge precursor. The formation of ZnA1204 indicates a strong potential for employing aluminum- and silicon-based materials to thermally immobilize zinc and achieve the beneficial use of metal-laden MSWI ash.
基金Project(50878080)supported by the National Natural Science Foundation of ChinaProject(K0902006-31)supported by the Key Scientific and Technological Special of Changsha City in China
文摘The general behavior of micron-particles in the inner domain of porous ceramic vessel was simulated by computational fluid dynamics software in terms of sampling experimental data.The results show that there is an optimum porosity of 0.32 to get a higher efficiency and lower pressure drop during filtration.According to the results of simulation and experiment,it is evident that lower inlet velocity can maintain lower pressure drop and obtain higher collection efficiency and inlet concentration also has a crucial influence on the collection efficiency.The collection efficiency of equipment increases significantly with the increase of inlet concentration when the inlet concentration is less than 6.3 g/m3,but it gradually tends to be stable in the range of 97.3%-99.7%when the inlet concentration is over this concentration.
基金Supported by National Natural Science Foundation of China (No.10772133 and No.11072172)Specialized Research Fund for the Doctoral Program of Higher Education of China (No. 20090032110006)
文摘Hydroxyapatite bioceramics is simulated by using finite element method （FEM）. The influences of porosity, hole shape, angle of crack and other parameters on the ceramics are analyzed. The results show that with the increase of the angle between crack and horizontal direction, the stress intensity factor KⅠ decreases gradually, but stress intensity factor KⅡ increases at first and then it decreases. The value of KⅡ reaches maximum when the angle between crack and horizontal direction is 45°. KⅠ and KⅡ rise with the increase of porosity, and they are almost the same for the circular and hexagonal holes. For elliptical holes, KⅠ and KⅡ reach maximum when the long axis of ellipse is perpendicular to the loading direction and they reach minimum when the same axis is parallel to the loading direction. Moreover, with the increase of the angle between the long axis and loading direction, KⅠ and KⅡ increase gradually.
基金supported by the National Natural Science Foundation of China (Grant Nos. 50962008,51162017)the Ministry of Education of China in Humanities and Social Sciences Research (Grant No.10YJC780013)
文摘Shapes are important clues for the identification of ancient ceramics.In this study,digital extraction methods of shape characterization were discussed,using samples of flared mouthed porcelain bowls produced in Jingdezhen Hutian Kiln from the Five Dynasties to the Song and Yuan period.By employing the techniques of image enhancement,edge detection and curve fitting of Matlab,the method using digital shape characterization has advanced accuracy and effectiveness of traditional identification which is based on visual and tactual inspections.Together with the increasingly applied compositional data analysis and thermoluminescence dating technique,the method will further improve and upgrade the scientific identification system for ancient ceramics.
基金the National Natural Science Foundation of China(Grant Nos.11172024 and 11232013)the National Key Basic Research Program of China(Grant No.2012CB937500)+3 种基金the Research Grant Council of the Hong Kong Special Administrative Region,China(Grant No.9042201(City U 11211015))resources provided by the Pawsey Supercomputing Centre with funding from the Australian Government and the Government of Western Australiathe LNMGrid of the State Key Laboratory of Nonlinear Mechanics and the Sc Grid of Supercomputing CenterComputer Network Information Center of the Chinese Academy of Sciences
文摘Oxygen vacancy, a kind of native point defects in ferroelectric ceramics, usually causes an increase of the dielectric loss. Based on experimental observations, it is believed that all of the oxygen vacancies are an unfavorable factor for energy saving. By using molecular dynamics simulations, we show that the increase of coercive and saturated electric fields is due to the difficulty to switch local polarization near an oxygen vacancy, and so that a ferroelectric device has to sustain the rising consumption of energy. The simulation results also uncover how oxygen vacancies influence ferroelectric properties.
