First a report about present status of circulating fluidized bed reactors for coal and multi-fuel combustion in power plants is given. Thereafter the development potentials and research needs for further improvement o...First a report about present status of circulating fluidized bed reactors for coal and multi-fuel combustion in power plants is given. Thereafter the development potentials and research needs for further improvement of CFB com-bustors operating with finely grained bed materials are discussed and recommendations for direction of further research and development work are presented.展开更多
Background In 2003, China＇s National Free Antiretroviral Treatment Program （NFATP） was initiated as a pilot, which covered only 100 HIV/AIDS patients. By 2011, the pilot had evolved into a nationwide program and ha...Background In 2003, China＇s National Free Antiretroviral Treatment Program （NFATP） was initiated as a pilot, which covered only 100 HIV/AIDS patients. By 2011, the pilot had evolved into a nationwide program and had provided free treatment for over 150 000 patients. The objective of this study was to report and evaluate the progress of China＇s free antiretroviral treatment program. Methods The NFATP Database was systematically reviewed and a total of 150 692 HIV/AIDS patients were included in this study. Program progress indicators including the number of treated HIV/AIDS patients, follow-up visit rate, CD4 test rate, and viral load test rate were summarized and examined over a calendar year to evaluate the progress of NFATP quantitatively and qualitatively. Results By the end of 2011, a total of 150 692 HIV/AIDS patients had been treated through the NFATP and 122 613 of them were still on treatment. Of all patients, about 72% were enrolled during the past four years. The dominant transmission route was blood related in the early phase of the NFATP, but gradually changed to sexual contact. Besides quantitative improvements, progress indicators also demonstrated significant qualitative improvements that the program had made during the past 9 years. Conclusions Great achievement has been made by China＇s NFATP. China＇s experience indicates the importance of a comprehensive response to the success of its treatment program. However, to ensure the quality and sustainability of treatment in the long term, more attention and resources should be paid towards program management.展开更多
The multi-scale structures of complex flows have been great challenges to both theoretical and engineer-ing researches, and multi-scale modeling is the natural way in response. Particle methods (PMs) are ideal constit...The multi-scale structures of complex flows have been great challenges to both theoretical and engineer-ing researches, and multi-scale modeling is the natural way in response. Particle methods (PMs) are ideal constitutors and powerful probes of multi-scale models, owing to their physical insight and computational simplicity. In this paper, the role of different PMs for multi-scale modeling of complex flows is critically reviewed and possible development of PMs in this background is prospected, with the emphasis on pseudo-particle modeling (PPM). The performances of some different PMs are compared in simulations and new devel-opment in the fundamentals and applications of PPM is also reported, demonstrating PPM as a unique PM for multi-scale modeling.展开更多
Scale-up of the high shear wet granulation （HSWG） process is considered a challenge because HSWG is complex and influenced by numerous factors, including equipment, formulation, and process variables. For a system o...Scale-up of the high shear wet granulation （HSWG） process is considered a challenge because HSWG is complex and influenced by numerous factors, including equipment, formulation, and process variables. For a system of microcrystalline cellulose and water, HSWG experiments at three scales （1, 2, and 4 L working vessel） were conducted with a granulator. Scale-up was implemented on the basis of a nucleation regime map approach. To keep dimensionless spray flux and drop penetration time constant, water addition time at three processing scales were 300, 442, and 700 s, respectively. The other process parameters were kept unchanged. Granule size distributions were plotted and compared, and scanning electron microscopy was used to analyze granule surface morphology. Physical characterization was undertaken using a modified SeDeM method. At nearly all scales, granule yield was greater than 85% and all the cosine values were larger than 0.89. At the same experiment points, granules at all scales had similar surface morphology and similar physical characteristics. The results demonstrate that a rational scaling-up of the HSWG process is feasible using a regime map approach.展开更多
Few studies have investigated scale-up of the residence-time distribution （RTD） of particles in bubbling fluidized beds （BFBs） with continuous particle flow. Two approaches were investigated in this study： first,...Few studies have investigated scale-up of the residence-time distribution （RTD） of particles in bubbling fluidized beds （BFBs） with continuous particle flow. Two approaches were investigated in this study： first, using well-known scaling laws that require changes in particle properties and gas velocity; second, using a simple approach keeping the same particles and gas velocity for different beds. Our theoretical analysis indicates it is possible to obtain similar RTDs in different BFBs with scaling laws if the plug-flow residence time （tpiug） is changed as m^0.5, where m is the scaling ratio of the bed; however, neither approach can ensure similar RTDs if tplug is kept invariant. To investigate RTD variations using two approaches without changing tplug, we performed experiments in three BFBs. The derivatives dE（θ）/dθ （where E（θ） is the dimensionless RTD density function and θ is the dimensionless time） in the early stage of the RTDs always varied with m 1, which was attributed to the fact that the particle movement in the early stage were mainly subject to dispersion. Using the simple approach, we obtained similar RTDs by separately treating the RTDs in the early and post-stages. This approach guarantees RTD similarity and provides basic rules for designing BFBs.展开更多
文摘First a report about present status of circulating fluidized bed reactors for coal and multi-fuel combustion in power plants is given. Thereafter the development potentials and research needs for further improvement of CFB com-bustors operating with finely grained bed materials are discussed and recommendations for direction of further research and development work are presented.
文摘Background In 2003, China＇s National Free Antiretroviral Treatment Program （NFATP） was initiated as a pilot, which covered only 100 HIV/AIDS patients. By 2011, the pilot had evolved into a nationwide program and had provided free treatment for over 150 000 patients. The objective of this study was to report and evaluate the progress of China＇s free antiretroviral treatment program. Methods The NFATP Database was systematically reviewed and a total of 150 692 HIV/AIDS patients were included in this study. Program progress indicators including the number of treated HIV/AIDS patients, follow-up visit rate, CD4 test rate, and viral load test rate were summarized and examined over a calendar year to evaluate the progress of NFATP quantitatively and qualitatively. Results By the end of 2011, a total of 150 692 HIV/AIDS patients had been treated through the NFATP and 122 613 of them were still on treatment. Of all patients, about 72% were enrolled during the past four years. The dominant transmission route was blood related in the early phase of the NFATP, but gradually changed to sexual contact. Besides quantitative improvements, progress indicators also demonstrated significant qualitative improvements that the program had made during the past 9 years. Conclusions Great achievement has been made by China＇s NFATP. China＇s experience indicates the importance of a comprehensive response to the success of its treatment program. However, to ensure the quality and sustainability of treatment in the long term, more attention and resources should be paid towards program management.
基金the National Natural Science Foundation of China(Grant Nos.20336040 , 20490201)the Chinese Academy of Sciences(Grant No.INF105-SCE-2-07).
文摘The multi-scale structures of complex flows have been great challenges to both theoretical and engineer-ing researches, and multi-scale modeling is the natural way in response. Particle methods (PMs) are ideal constitutors and powerful probes of multi-scale models, owing to their physical insight and computational simplicity. In this paper, the role of different PMs for multi-scale modeling of complex flows is critically reviewed and possible development of PMs in this background is prospected, with the emphasis on pseudo-particle modeling (PPM). The performances of some different PMs are compared in simulations and new devel-opment in the fundamentals and applications of PPM is also reported, demonstrating PPM as a unique PM for multi-scale modeling.
基金The authors acknowledge research funding support from the Beijing Natural Science Foundation of China： study on the dimensionless modeling of high shear wet granulation process for Tanshinone extract （No. 7154217）, joint development program funding from the Beijing Municipal Education Commission of China （Key Laboratory Construction Project： study on the integrated modeling and optimization technology of the pharmaceutical process of Chinese medicine preparations）, and the program funding from the National Natural Science Foundation of China： study on the quality transfer model and global optimization method of the chained pharmaceutical process of Chinese medicine products （No. B1403112）.
文摘Scale-up of the high shear wet granulation （HSWG） process is considered a challenge because HSWG is complex and influenced by numerous factors, including equipment, formulation, and process variables. For a system of microcrystalline cellulose and water, HSWG experiments at three scales （1, 2, and 4 L working vessel） were conducted with a granulator. Scale-up was implemented on the basis of a nucleation regime map approach. To keep dimensionless spray flux and drop penetration time constant, water addition time at three processing scales were 300, 442, and 700 s, respectively. The other process parameters were kept unchanged. Granule size distributions were plotted and compared, and scanning electron microscopy was used to analyze granule surface morphology. Physical characterization was undertaken using a modified SeDeM method. At nearly all scales, granule yield was greater than 85% and all the cosine values were larger than 0.89. At the same experiment points, granules at all scales had similar surface morphology and similar physical characteristics. The results demonstrate that a rational scaling-up of the HSWG process is feasible using a regime map approach.
文摘Few studies have investigated scale-up of the residence-time distribution （RTD） of particles in bubbling fluidized beds （BFBs） with continuous particle flow. Two approaches were investigated in this study： first, using well-known scaling laws that require changes in particle properties and gas velocity; second, using a simple approach keeping the same particles and gas velocity for different beds. Our theoretical analysis indicates it is possible to obtain similar RTDs in different BFBs with scaling laws if the plug-flow residence time （tpiug） is changed as m^0.5, where m is the scaling ratio of the bed; however, neither approach can ensure similar RTDs if tplug is kept invariant. To investigate RTD variations using two approaches without changing tplug, we performed experiments in three BFBs. The derivatives dE（θ）/dθ （where E（θ） is the dimensionless RTD density function and θ is the dimensionless time） in the early stage of the RTDs always varied with m 1, which was attributed to the fact that the particle movement in the early stage were mainly subject to dispersion. Using the simple approach, we obtained similar RTDs by separately treating the RTDs in the early and post-stages. This approach guarantees RTD similarity and provides basic rules for designing BFBs.
