Optimal process characteristics of melting of polyisoprene

Author(s):  
K. Mohanraj ◽  
Rajakumar S. Rai ◽  
M. Suresh ◽  
B. Logapriya ◽  
S. Marichamy ◽  
...  
2019 ◽  
Vol 2 (5) ◽  
Author(s):  
Mengda Zhang ◽  
Chenjing Zhou ◽  
Tian-tian Zhang ◽  
Yan Han

Selecting check index quantitatively is the core of the calibration of micro traffic simulation parameters at signal intersection. Five indexes in the node (intersection) module of VISSIM were selected as the check index set. Twelve simulation parameters in the core module were selected as the simulation parameters set. Optimal process of parameter calibration was proposed and model of the intersection of Huangcun west street and Xinghua street in Beijing was built in VISSIM to verify it. The sensitivity analysis between each check index and simulation parameter in their own set was conducted respectively. Sensitive parameter sets of different check indices were obtained and compared. The results show that different indexes have different size of set, and average vehicle delay's is maximum, so it's necessary to select index quantitatively. The results can provide references for scientific selection of the check indexes and improve the study efficiency of parameter calibration.


2019 ◽  
Vol 14 (2) ◽  
pp. 82-88
Author(s):  
M.V. Alekseev ◽  
I.S. Vozhakov ◽  
S.I. Lezhnin

A numerical simulation of the process of the outflow of gas under pressure into a closed container partially filled with liquid was carried out. For comparative theoretical analysis, an asymptotic model was used with assumptions about the adiabaticity of the gas outflow process and the ideality of the liquid during the oscillatory one-dimensional motion of the liquid column. In this case, the motion of the liquid column and the evolution of pressure in the gas are determined by the equation of dynamics and the balance of enthalpy. Numerical simulation was performed in the OpenFOAM package using the fluid volume method (VOF method) and the standard k-e turbulence model. The evolution of the fields of volumetric gas content, velocity, and pressure during the flow of gas from the high-pressure chamber into a closed channel filled with liquid in the presence of a ”gas blanket“ at the upper end of the channel is obtained. It was shown that the dynamics of pulsations in the gas cavity that occurs when the gas flows into the closed region substantially depends on the physical properties of the liquid in the volume, especially the density. Numerical modeling showed that the injection of gas into water occurs in the form of a jet outflow of gas, and for the outflow into liquid lead, a gas slug is formed at the bottom of the channel. Satisfactory agreement was obtained between the numerical calculation and the calculation according to the asymptotic model for pressure pulsations in a gas projectile in liquid lead. For water, the results of calculations using the asymptotic model give a significant difference from the results of numerical calculations. In all cases, the velocity of the medium obtained by numerical simulation and when using the asymptotic model differ by an order of magnitude or more.


1981 ◽  
Vol 46 (9) ◽  
pp. 2032-2042 ◽  
Author(s):  
Pavel Seichter

A conductivity method has been used to assess the homogenization efficiency of screw impellers with draught tubes. The value of the criterion of homochronousness, i.e. the dimensionless time of homogenization, in the creeping flow regime of Newtonian liquids is dependent on the geometrical simplexes of the mixing system. In particular, on the ratio of diameters of the vessel and the impeller and on the ratio of the screw lead to the impeller diameter. Expression have been proposed to calculate the mixing times. Efficiency has been examined of individual configurations of screw impellers. The lowest energy requirements for homogenization have been found for the system with the ratio D/d = 2.


1981 ◽  
Vol 46 (9) ◽  
pp. 2021-2031 ◽  
Author(s):  
Pavel Seichter

Velocity profiles and pumping capacity have been determined using a thermistor anemometer in a vessel equipped with a screw impeller. In region of the creeping flow of a Newtonian liquid, i.e. for Re <15, the dimensionless pumping capacity is dependent on the geometrical arrangement of the mixing system. The efficiency was assessed of individual configuration from the value energy criterion expressing the dimensionless power requirements for recirculation of a highly viscous liquid in a vessel equipped with a screw impeller.


2007 ◽  
Vol 2 (1) ◽  
pp. 33-48
Author(s):  
Graciela Brusa ◽  
María Laura Caliusco ◽  
Omar Chiotti

Nowadays, organizational innovation constitutes the government challenges for providing better and more efficient services to citizens, enterprises or other public offices. E–government seems to be an excellent opportunity to work on this way. The applications that support front-end services delivered to users have to access information systems of multiple government areas. This is a significant problem for e-government back-office since multiple platforms and technologies coexist. Moreover, in the back-office there is a great volume of data that is implicit in the software applications that support administration activities. In this context, the main requirement is to make available the data managed in the back-office for the e-government users in a fast and precise way, without misunderstanding. To this aim, it is necessary to provide an infrastructure that make explicit the knowledge stored in different government areas and deliver this knowledge to the users. This paper presents an approach on how ontological engineering techniques can be applied to solving the problems of content discovery, aggregation, and sharing in the e-government back-office. This approach is constituted by a specific process to develop an ontology in the public sector and an ontology-based architecture. In order to present the process characteristics, a case study applied to a local government domain is analyzed. This domain is the budget and financial information of Santa Fe Province (Argentine).


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