Introduction. Because of high demand for polymer products, there are constantly modernized the technological aspects of their production, a huge share of which is based on the use of ...microheterogeneous catalytic systems. Physicochemical properties of polymer products can be improved through targeted hydrodynamic effect in turbulent flows. The study of physicochemical patterns of polymer product synthesis in the presence of modified catalytic systems is of great interest.
Aim of the Article. The article is aimed at evaluating the efficiency of hydrodynamic influence in turbulent flows on the type of catalyst heterogeneity and the kinetics of polymer production processes.
Materials and Methods. In the study of polymer synthesis processes, there is used a simulation approach to the system model description that is based on the idea of reproducing various scenarios of uninterrupted production and conducting the necessary empirical analysis. Parallel programming and cloud computing technologies are used in simulation modeling to increase computational speed.
Results. A methodology for solving inverse problems has been developed to determine the influence of external factors on the kinetic activity and heterogeneity of active centers on the basis of known physicochemical information. The use of simulation modeling with the application of cloud computing technology makes it possible to unambiguously determine the type of kinetic heterogeneity in the conditions of averaging the reactive capacity of active centers.
Discussion and Conclusion. Approbation of the new simulation approach to the solution of the inverse problem allowed evaluating the efficiency of the influence of the tube turbulent apparatus on the kinetics of producing polyisoprene in the presence of titanium catalyst and identifying the presence of two active centers: type ATi − lnM = 13.4, type BTi − lnM = 11.7, while the proportion of active centers type ATi is 0.91; type BTi – 0.09. Based on the data obtained, it becomes possible to formulate and solve inverse problems of identifying kinetic parameters for further model description of the system.
Introduction. Under conditions of high demand for rubber products, continuous modernization of technological processes of continuous production is carried out. One of the tools to control the ...physical and chemical parameters of the resulting product is the technology of multipoint feeding of controlling impurities that can significantly affect the molecular characteristics of polymers. However, it is difficult to experimentally select the technology of multipoint feeding of controlling impurities to achieve the given molecular characteristics of polymers.
Aim of the Article. To create a methodology that allows using the tools of model system description to carry out directed regulation and construction of the technological process to achieve a given molecular weight distribution.
Materials and Methods. For more accurate mathematical modeling of polymer synthesis processes, two approaches to the model description of the system under study are considered: 1) Kinetic approach. In this case, the developed algorithm is based on the method of moments in combination with numerical methods for solving systems of ordinary differential equations that characterize the change in the material balance for each reaction component. When describing large-tonnage production, a modular principle is proposed, according to which the kinetics model is supplemented by hydrodynamic regularities that depend on the reactor type. 2) Statistical approach (Monte Carlo method). The algorithm for implementing the statistical approach is based on the probabilistic nature of elementary reactions. To describe the process in the reactor cascade, a systematic approach to the organization of calculations is proposed.
Results. Using kinetic and statistical approaches new dependences of conversion and characteristic viscosity on polymerizer number were obtained, which showed satisfactory agreement with the values of the experimental results. Comparative analysis of calculated molecular-mass distribution curves of obtained product was carried out. The analysis confirms the significant influence of different modes of regulator feeding on molecular characteristics of polymer.
Discussion and Conclusion. The analysis of the molecular chain structure of the copolymerization product under conditions of adding the third control point characterizes the decrease in rigidity and increase in elasticity of the resulting product, and the created digital evaluation tools allow by means of computational experiments to select optimal parameters of the regulator feeding in order to obtain polymers with a given molecular mass.
The CBM RICH project Adamczewski-Musch, J.; Becker, K.-H.; Belogurov, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2014, Volume:
766
Journal Article
Peer reviewed
The Compressed Baryonic Matter (CBM) experiment will study the properties of super dense nuclear matter by means of heavy ion collisions at the future FAIR facility. An integral detector component is ...a large Ring Imaging Cherenkov detector with CO sub(2) gas radiator, which will mainly serve for electron identification and pion suppression necessary to access rare dileptonic probes like e super(+)e super(-) decays of light vector mesons or J/ psi psi . We describe the design of this future RICH detector and focus on results obtained by building a CBM RICH detector prototype tested at CERN-PS.
Abstract
A mathematical model of the process of producing polyisoprene in the presence of various catalytic systems of the Ziegler-Natta type is constructed in the article. When developing a ...mathematical model, the polycentric nature of the applied catalytic system was taken into account and the modular construction principle was applied, which allows calculations to be made both for the batch mode of the process and for the continuous mode. An analysis was also made of the influence of the hydrodynamic regime on the polymerization rate and the molecular characteristics of the resulting product using the example of a titanium-containing catalyst system.
The Compressed Baryonic Matter (CBM) experiment is a dedicated heavy ion collision experiment at the FAIR facility. It will be one of the first HEP experiments which works in a triggerless mode: data ...received in the DAQ
from the detectors will not be associated with events by a hardware trigger anymore. All raw data within a giventime period will be collected continuously in containers, so-called time-slices. The task of the reconstruction algorithms is to create events out of this raw data stream. In this contribution, the optimization of the reconstruction software in the RICH detector to the free-streaming data flow is presented. The implementation of ring reconstruction algorithms which use time measurements of the hits as an additional parameter is discussed.
Abstract
The article describes an algorithm for modeling the isoprene polymerization process based on the Monte Carlo method. The algorithm can be used to simulate polymerization processes carried ...out in batch or continuous mode. The possible polycentricity of the catalyst used is also taken into account. The model is based on this algorithm makes it possible to study the properties of the polymerization product and calculate the molecular weight distribution for different points in time.
Event reconstruction in the RICH detector of the CBM experiment at FAIR Adamczewski, J.; Becker, K.-H.; Belogurov, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2014, Volume:
766
Journal Article
Peer reviewed
The Compressed Baryonic Matter (CBM) experiment at the future FAIR facility will investigate the QCD phase diagram at high net-baryon densities and moderate temperatures. One of the key signatures ...will be di-leptons emitted from the hot and dense phase in heavy-ion collisions. Measuring di-electrons, a high purity of identified electrons is required in order to suppress the background. Electron identification in CBM will be performed by a Ring Imaging Cherenkov (RICH) detector and Transition Radiation Detectors (TRD). In order to access the foreseen rare probes, the detector and the data acquisition have to handle interaction rates up to 10 MHz. Therefore, the development of fast and efficient event reconstruction algorithms is an important and challenging task in CBM. In this contribution event reconstruction and electron identification algorithms in the RICH detector are presented. So far they have been developed on simulated data but could already be tested on real data from a RICH prototype testbeam experiment at the CERN-PS. Efficient and fast ring recognition algorithms in the CBM-RICH are based on the Hough Transform method. Due to optical distortions of the rings, an ellipse fitting algorithm was elaborated to improve the ring radius resolution. An efficient algorithm based on the Artificial Neural Network was implemented for electron identification in RICH. All algorithms were significantly optimized to achieve maximum speed and minimum memory consumption.
The kinetic heterogeneity of the gadolinium-based catalytic system in 1,4-
cis
-polyisoprene synthesis was studied. The final form of the active site distribution function at preset accuracy was ...obtained by setting and solving the inverse problem of the molecular-mass distribution formation using the Tikhonov’s regularization method and numerical calculation methods. The results obtained show that there are at least three types of active sites with different kinetic activity in the system.
The CBM experiment at the future FAIR facility will explore nuclear matter at high net-baryon densities. One of the key observables is di-leptons as they penetrate the created matter without further ...strong interactions. A gaseous RICH detector in a standard projective geometry using spherical mirrors is one of two detector elements for the required electron identification. The mirror system consists of about 72 trapezoidal mirror tiles. Any misalignment between the tiles relative to the nominal common spherical surface leads to reduction of the reconstruction efficiency of Cherenkov rings and deterioration of their resolution. To determine tolerances in mirror misalignment extensive simulation and measurement studies were carried out. Pure CO sub(2) will be used as radiator gas. Gas contamination, mainly moisture and Oxygen, reduces the number of detected photons per ring and worsens the quality of reconstructed Cherenkov rings. Therefore a study was carried out to determine tolerances in radiator gas contamination.
PDF
