The aim of the present research is to provide a technique for preparing open-cell Al2O3-ZrO2 ceramic foams with uniform cell size.This technique used plant seeds to array templates and centrifugal slip casting to obta...The aim of the present research is to provide a technique for preparing open-cell Al2O3-ZrO2 ceramic foams with uniform cell size.This technique used plant seeds to array templates and centrifugal slip casting to obtain cell struts with high packing density.Aqueous Al2O3-ZrO2 slurries with up to 50 vol.% solid contents were prepared and the rheological characteristic of the slurries was investigated.Consolidation was performed at an acceleration of 2,860 g for 60 min.The effect of the characteristic of plant seeds on the drying behavior of Al2O3-ZrO2 green compact was analyzed.The effects of the solid contents of slurries on segregation phenomena of Al2O3 and ZrO2 particles and green compact uniformity were investigated.The compressive stress-strain curve and deformation behavior of Al2O3-ZrO2 ceramic foams prepared using plant seed template were analyzed.The results showed segregation phenomenon is negligible for highly stable slurry with 50 vol.% solid loading.The prepared cell struts of Al2O3-ZrO2 foams have high green density (61.9% TD), sintered density (99.1% TD) and homogeneous microstructure.When sintered at 1,550 ℃ for 2 h, the cell size of Al2O3-ZrO2 foam is approximately uniform and the diameter is about 1.1 mm.The porosity and compressive strength of sintered products is 66.2% and 5.86 MPa, respectively.展开更多
In present study, BP neural network model was proposed for the prediction of ultimate compressive strength of Al2O3-ZrO2 ceramic foam filter prepared by centrifugal slip casting. The inputs of the BP neural network mo...In present study, BP neural network model was proposed for the prediction of ultimate compressive strength of Al2O3-ZrO2 ceramic foam filter prepared by centrifugal slip casting. The inputs of the BP neural network model were the applied load on the epispastic polystyrene template (F), centrifugal acceleration (v) and sintering temperature (T), while the only output was the ultimate compressive strength (σ). According to the registered BP model, the effects of F, v, T on σ were analyzed. The predicted results agree with the actual data within reasonable experimental error, indicating that the BP model is practically a very useful tool in property prediction and process parameter design of the Al2O3-ZrO2 ceramic foam filter prepared by centrifugal slip casting.展开更多
Systems science and systems engineering, as a new science and technology domain in modern science and technology, is developing rapidly, and showing greater and greater vitality. QIAN Xuesen is recognized as the pione...Systems science and systems engineering, as a new science and technology domain in modern science and technology, is developing rapidly, and showing greater and greater vitality. QIAN Xuesen is recognized as the pioneer and founder of systems science and systems engineering in China. His whole innovation process from systems thinking to systems practice has made pioneering contributions at different levels from engineering, technology, science to philosophy. These achievements and contributions have very important scientific value and practical significance. Presenting QIAN Xuesen's contribution in systems science and practice, this paper elaborates the development and application of systems science and systems engineering.展开更多
The aim of the present research is to provide a novel technique for preparing gradient Al 2 O 3-ZrO 2 ceramic foams.This technique used epispastic polystyrene spheres to array templates and centrifugal slip casting to...The aim of the present research is to provide a novel technique for preparing gradient Al 2 O 3-ZrO 2 ceramic foams.This technique used epispastic polystyrene spheres to array templates and centrifugal slip casting to obtain cell struts with gradient distribution of Al 2 O 3 and ZrO 2 particles and high packing density.Aqueous Al 2 O 3-20vol.% ZrO 2 slurries with 20vol.% solid contents were prepared and the dispersion and rheological characteristics of the slurries were investigated.The settling velocity and mass segregation of Al 2 O 3 and ZrO 2 particles at different centrifugal accelerations were calculated and studied.The drying behavior,macrostructure,microstructure,compressive property and resistance to thermal shock of the sintered products were also investigated.The results show that the difference of settling velocity of Al 2 O 3 and ZrO 2 particles increases and mass segregation becomes acute with an increase in centrifugal acceleration.The cell struts prepared at a centrifugal acceleration of 1,690 g have high sintered density(99.0% TD) and continuous gradient distribution of Al 2 O 3 and ZrO 2 particles.When sintered at 1,550 o C for 2 h,the cell size of gradient Al 2 O 3-ZrO 2 foam is approximately uniform,about 1.1 mm.With the porosity of gradient Al 2 O 3-ZrO 2 ceramic foams increasing from 75.3% to 83.0%,the compressive strength decreases from 4.4 to 2.4 MPa,and the ceramic foams can resist 8-11 repeated thermal shock from 1,100 o C to room temperature.展开更多
BP neural network was used in this study to model the porosity and the compressive strength of a gradient Al2O3-ZrO2ceramic foam f ilter prepared by centrifugal slip casting.The inf luences of the load applied on the ...BP neural network was used in this study to model the porosity and the compressive strength of a gradient Al2O3-ZrO2ceramic foam f ilter prepared by centrifugal slip casting.The inf luences of the load applied on the epispastic polystyrene template(F),the centrifugal acceleration(v)and sintering temperature(T)on the porosity(P)and compressive strength(σ)of the sintered products were studied by using the registered three-layer BP model.The accuracy of the model was verif ied by comparing the BP model predicted results with the experimental ones.Results show that the model prediction agrees with the experimental data within a reasonable experimental error,indicating that the three-layer BP network based modeling is effective in predicting both the properties and processing parameters in designing the gradient Al2O3-ZrO2ceramic foam f ilter.The prediction results show that the porosity percentage increases and compressive strength decreases with an increase in the applied load on epispastic polystyrene template.As for the inf luence of sintering temperature,the porosity percentage decreases monotonically with an increase in sintering temperature,yet the compressive strength f irst increases and then decreases slightly in a given temperature range.Furthermore,the porosity percentage changes little but the compressive strength f irst increases and then decreases when the centrifugal acceleration increases.展开更多
基金supported by the National Natural Science Foundation of China (50672014)Innovation Research Team Program of the Ministry of Education (IRT0713)
文摘The aim of the present research is to provide a technique for preparing open-cell Al2O3-ZrO2 ceramic foams with uniform cell size.This technique used plant seeds to array templates and centrifugal slip casting to obtain cell struts with high packing density.Aqueous Al2O3-ZrO2 slurries with up to 50 vol.% solid contents were prepared and the rheological characteristic of the slurries was investigated.Consolidation was performed at an acceleration of 2,860 g for 60 min.The effect of the characteristic of plant seeds on the drying behavior of Al2O3-ZrO2 green compact was analyzed.The effects of the solid contents of slurries on segregation phenomena of Al2O3 and ZrO2 particles and green compact uniformity were investigated.The compressive stress-strain curve and deformation behavior of Al2O3-ZrO2 ceramic foams prepared using plant seed template were analyzed.The results showed segregation phenomenon is negligible for highly stable slurry with 50 vol.% solid loading.The prepared cell struts of Al2O3-ZrO2 foams have high green density (61.9% TD), sintered density (99.1% TD) and homogeneous microstructure.When sintered at 1,550 ℃ for 2 h, the cell size of Al2O3-ZrO2 foam is approximately uniform and the diameter is about 1.1 mm.The porosity and compressive strength of sintered products is 66.2% and 5.86 MPa, respectively.
基金financially supported by the Innovation Research Team Program of the Ministry of Education(IRT0713)the Key Laboratory of New Materials in Automobile of Liaoning Province(grant No.201016201)Doctoral Initiating Project of Liaoning Province Foundation for Natural Sciences,China
文摘In present study, BP neural network model was proposed for the prediction of ultimate compressive strength of Al2O3-ZrO2 ceramic foam filter prepared by centrifugal slip casting. The inputs of the BP neural network model were the applied load on the epispastic polystyrene template (F), centrifugal acceleration (v) and sintering temperature (T), while the only output was the ultimate compressive strength (σ). According to the registered BP model, the effects of F, v, T on σ were analyzed. The predicted results agree with the actual data within reasonable experimental error, indicating that the BP model is practically a very useful tool in property prediction and process parameter design of the Al2O3-ZrO2 ceramic foam filter prepared by centrifugal slip casting.
文摘Systems science and systems engineering, as a new science and technology domain in modern science and technology, is developing rapidly, and showing greater and greater vitality. QIAN Xuesen is recognized as the pioneer and founder of systems science and systems engineering in China. His whole innovation process from systems thinking to systems practice has made pioneering contributions at different levels from engineering, technology, science to philosophy. These achievements and contributions have very important scientific value and practical significance. Presenting QIAN Xuesen's contribution in systems science and practice, this paper elaborates the development and application of systems science and systems engineering.
基金financially supported by the Natural Science Foundation of Liaoning Province(No.:201102090)the Doctoral Initiating Project of Liaoning Province Foundation for Natural Sciences,China(No.:20111068)+2 种基金the High School Development Plan for Distinguished Young Scholars of Liaoning Province Education Committee(No.:LJQ2012056)the National High-Tech Research and Development Program of China("863"Program,No.:2011AA060102)the International Science and Technology Cooperation Program of China,(No.:2011DFR50270)
文摘The aim of the present research is to provide a novel technique for preparing gradient Al 2 O 3-ZrO 2 ceramic foams.This technique used epispastic polystyrene spheres to array templates and centrifugal slip casting to obtain cell struts with gradient distribution of Al 2 O 3 and ZrO 2 particles and high packing density.Aqueous Al 2 O 3-20vol.% ZrO 2 slurries with 20vol.% solid contents were prepared and the dispersion and rheological characteristics of the slurries were investigated.The settling velocity and mass segregation of Al 2 O 3 and ZrO 2 particles at different centrifugal accelerations were calculated and studied.The drying behavior,macrostructure,microstructure,compressive property and resistance to thermal shock of the sintered products were also investigated.The results show that the difference of settling velocity of Al 2 O 3 and ZrO 2 particles increases and mass segregation becomes acute with an increase in centrifugal acceleration.The cell struts prepared at a centrifugal acceleration of 1,690 g have high sintered density(99.0% TD) and continuous gradient distribution of Al 2 O 3 and ZrO 2 particles.When sintered at 1,550 o C for 2 h,the cell size of gradient Al 2 O 3-ZrO 2 foam is approximately uniform,about 1.1 mm.With the porosity of gradient Al 2 O 3-ZrO 2 ceramic foams increasing from 75.3% to 83.0%,the compressive strength decreases from 4.4 to 2.4 MPa,and the ceramic foams can resist 8-11 repeated thermal shock from 1,100 o C to room temperature.
基金financially supported by the Natural Science Foundation of Liaoning Province(No.201102090)the Doctoral Initiating Project of Liaoning Province Foundation for Natural Sciences,China(No.20111068)+1 种基金the High School Development Plan for Distinguished Young Scholars of Liaoning Province Education Committee(No.LJQ2012056)the National High-Tech Research and Development Program of China("863"Program,No.2011AA060102)
文摘BP neural network was used in this study to model the porosity and the compressive strength of a gradient Al2O3-ZrO2ceramic foam f ilter prepared by centrifugal slip casting.The inf luences of the load applied on the epispastic polystyrene template(F),the centrifugal acceleration(v)and sintering temperature(T)on the porosity(P)and compressive strength(σ)of the sintered products were studied by using the registered three-layer BP model.The accuracy of the model was verif ied by comparing the BP model predicted results with the experimental ones.Results show that the model prediction agrees with the experimental data within a reasonable experimental error,indicating that the three-layer BP network based modeling is effective in predicting both the properties and processing parameters in designing the gradient Al2O3-ZrO2ceramic foam f ilter.The prediction results show that the porosity percentage increases and compressive strength decreases with an increase in the applied load on epispastic polystyrene template.As for the inf luence of sintering temperature,the porosity percentage decreases monotonically with an increase in sintering temperature,yet the compressive strength f irst increases and then decreases slightly in a given temperature range.Furthermore,the porosity percentage changes little but the compressive strength f irst increases and then decreases when the centrifugal acceleration increases.
