Methodological approach to the spatial plan of the river belt

Based on the main assumptions of the Spatial Plan of the Republic of Serbia in regard to the Danube-Sava river belt, this paper gives an overview of the methodology of this area's spatial plan elaboration. The importance of this belt for the integration and development of Serbia, the spatial scope and complexity of the task, imposed new approaches to defining methodology and the elaboration procedure of this spatial plan. During the preparation phase oft the Spatial Plan of the Danube-Sava River belt it was projected that it should be elaborated in two main phases. The first phase ought to define the overall development strategy, the space utilization, protection and arrangement of the river belt and its gravitating areas (outlined by districts' territories along the Danube and the Sava). The second phase of the Spatial Plan should be elaborated as a structural/physical plan divided into seven belt's segments (outlined by territories of local communities along two rivers)

Determination and Application of Improved Kinetic Parameters for Simulation of Maleic Anhydride Synthesis in Industrial Fixed-Bed Reactor

The aims of this study were to determine improved kinetic parameters in five kinetic models for oxidation of n-butane into maleic anhydride in an industrial fixed-bed reactor, and to simulate the reactor performance. On the basis of the measured process parameters, inlet and outlet concentrations of n-butane were calculated and then used to fit the kinetic models. The industrial fixed-bed reactor was approximated by 10 continuous stirred tank reactors (CSTR) connected in series. Based on the calculated outlet concentration of n-butane from the industrial reactor, the outlet concentration of n-butane from the penultimate reactor was calculated. Then the concentrations of n-butane were calculated until the inlet concentration of n-butane in the first reactor was obtained. Kinetic parameters were determined by comparing the inlet concentrations of n-butane in the first reactor with the inlet concentration of n-butane obtained on the basis of the measured process parameters ​​in the industrial fixed-bed reactor. Kinetic models with improved kinetic parameters showed better simulation results compared to kinetic models with the existing kinetic parameters. The best agreement of simulation results and measured values was achieved with application of the kinetic model 2 (Equations (2a-c)). The smallest deviations of numerical simulation in comparison with measured values of the outlet pressure of reaction mixture were 0.45, 0.75 and 0.75% for application of the kinetic model 3 (Equations (3a-c)). The percentage deviations of numerical simulation with improved kinetic parameters and the existing kinetic parameters in comparison with measured values of inside reactor temperature were in the range 0.90-5.36% and in the range 4.17-9.78% (kinetic model 2, Equations (2a-c)), respectively. Keywords: kinetic parameters, kinetic models, maleic anhydride, simulation, fixed-bed reacto

Methodology for statistical analysis of squat rail defects

This paper proposes a methodology for statistical analysis of data obtained by visual inspection of squat defects on the rail head. Rail inspection by visual observation, including measurement of the squat defect position and depth was performed in Pančevo Varoš railway station in 2017. The obtained data about the squat rail defect (defect type 227 according to the UIC 712) on the main tracks was analysed in this paper. The rail defect position was determined regarding the position of the nearest sleeper in the track. Statistical analysis of the occurrence of squat rail defect was conducted according to the performed visual inspection in the field. Statistical data processing was performed for tracks zones according to the vertical stiffness of rail support. Furthermore, the impact of traffic load, the type and the arrangement of sleepers on the appearance of the squat rail defect was considered