in present paper, dynamic behavior and control of a fluidized bed reactor for polyethylene production has been considered. a double active sites model for ziegler-natta catalysts is used for simulation of polymerization reaction. hydrodynamic behavior of the bed is modeled using a two phase model including bubble and emulsion phases in which bubble phase has plug flow pattern with differentiall...

Program understanding tools manipulate program representations, such as abstract syntax trees, controlflow graphs, or data-flow graphs. This paper deals with the use of visitor combinators to conduct such manipulations. Visitor combinators are an extension of the well-known visitor design pattern. They are small, reusable classes that carry out specific visiting steps. They can be composed in d...

In this paper, in order to understand the flow-pipe interaction more clearly, the variations on flow pattern around semi-buried pipelines due to steady current have physically and numerically been investigated. In physical modeling section, the experiments have been carried out in a flume with 10 meter length, 0.3 meter width and 0.5 meter depth using a P.V.C pipe with 6.35 cm in diameter (for ...

The amoeboid organism, the plasmodium of Physarum polycephalum, behaves on the basis of spatio-temporal pattern formation by local contraction-oscillators. This biological system can be regarded as a reaction-diffusion system which has spatial interaction by active flow of protoplasmic sol in the cell. Paying attention to the physiological evidence that the flow is determined by contraction pat...

Objective- Obtaining the normal images ofcolor doppler and estimation ofblood flow velocity parametersof femoral and axillary arteries in dog.Design- Descriptive studyAnimals- 7 healthy adult mixed-breed dogs, weighing 14.3 ± 2.8 kg (mean ± SD).Proceudure- Left and right femoral and axillary arteries of hind and forelimbs were evaluated. Colorand spectral doppler images ofthe each artery were o...