For modeling and simulation of distillation process, there are lots of special purpose simulators along with their model libraries, such as Aspen Plus and HYSYS. However, the models in these tools lack of flexibility ...For modeling and simulation of distillation process, there are lots of special purpose simulators along with their model libraries, such as Aspen Plus and HYSYS. However, the models in these tools lack of flexibility and are not open to the end-user. Models developed in one tool can not be conveniently used in others because of the barriers among these simulators. In order to solve those problems, a flexible and extensible distillation system model library is constructed in this study, based on the Modelica and Modelica-supported platform MWorks, by the object-oriented technology and level progressive modeling strategy. It supports the reuse of knowledge on different granularities： physical phenomenon, unit model and system model. It is also an interface-friendly, accurate, fast PC-based and easily reusable simulation tool, which enables end-user to customize and extend the framework to add new functionality or adapt the simulation behavior as required. It also allows new models to be composed programmatically or graphically to form more complex models by invoking the existing components. A conventional air distillation column model is built and calculated using the library, and the results agree well with that simulated in Anen Plus.展开更多
One of the species candidates to rehabilitate arid rangelands of Morocco is Artemisia herba-alba Asso. （white Wormwood）. Unfortunately, overgrazing is by far the most important factor causing the reduction of cover ...One of the species candidates to rehabilitate arid rangelands of Morocco is Artemisia herba-alba Asso. （white Wormwood）. Unfortunately, overgrazing is by far the most important factor causing the reduction of cover and disappearance of this plant. In order to assess the effect of season and grazing on the recovery ofA. herba-alba Asso., plants of similar size were collected from Gourrama region and transplanted in the Experimental Station of Errachidia. These plants were submitted to different clipping heights （Cl = 8 cm, C2 = 15 cm, C3 = 25 cm） during two growing periods： autumn （stage of seed filling） and spring （before the starting of flowering）. Mean results show highly significant （P 〈 0.01） differences between the three treatments during the two periods. The increase of the plant volume clipped influences the performances of production and regrowth, the study has shown that the cutting level C 1 affect negatively the Artemisia performances, in fact 60% of plants cut at this height have died after the second clipping against 25% for C2 and 4.2% for C3. The parameters of growth and modular dynamic of branches are also affected by the cutting height C 1. The phytomass produced after the first cutting results in highly significant differences （P 〈 0.0 l） between the three cutting heights. Finally, the study demonstrated that for better regrowth, the taller height C3 is the most convenient for white Wormwood during the two periods, but the cutting height C2 can also be adopted for the autumn period.展开更多
基金Supported by the Major State Basic Research Development Program of China (2011CB706502)
文摘For modeling and simulation of distillation process, there are lots of special purpose simulators along with their model libraries, such as Aspen Plus and HYSYS. However, the models in these tools lack of flexibility and are not open to the end-user. Models developed in one tool can not be conveniently used in others because of the barriers among these simulators. In order to solve those problems, a flexible and extensible distillation system model library is constructed in this study, based on the Modelica and Modelica-supported platform MWorks, by the object-oriented technology and level progressive modeling strategy. It supports the reuse of knowledge on different granularities： physical phenomenon, unit model and system model. It is also an interface-friendly, accurate, fast PC-based and easily reusable simulation tool, which enables end-user to customize and extend the framework to add new functionality or adapt the simulation behavior as required. It also allows new models to be composed programmatically or graphically to form more complex models by invoking the existing components. A conventional air distillation column model is built and calculated using the library, and the results agree well with that simulated in Anen Plus.
文摘One of the species candidates to rehabilitate arid rangelands of Morocco is Artemisia herba-alba Asso. （white Wormwood）. Unfortunately, overgrazing is by far the most important factor causing the reduction of cover and disappearance of this plant. In order to assess the effect of season and grazing on the recovery ofA. herba-alba Asso., plants of similar size were collected from Gourrama region and transplanted in the Experimental Station of Errachidia. These plants were submitted to different clipping heights （Cl = 8 cm, C2 = 15 cm, C3 = 25 cm） during two growing periods： autumn （stage of seed filling） and spring （before the starting of flowering）. Mean results show highly significant （P 〈 0.01） differences between the three treatments during the two periods. The increase of the plant volume clipped influences the performances of production and regrowth, the study has shown that the cutting level C 1 affect negatively the Artemisia performances, in fact 60% of plants cut at this height have died after the second clipping against 25% for C2 and 4.2% for C3. The parameters of growth and modular dynamic of branches are also affected by the cutting height C 1. The phytomass produced after the first cutting results in highly significant differences （P 〈 0.0 l） between the three cutting heights. Finally, the study demonstrated that for better regrowth, the taller height C3 is the most convenient for white Wormwood during the two periods, but the cutting height C2 can also be adopted for the autumn period.
