Measuring of thickness of the asphalt pavement with Use of GPR
The results of development, tests and application of the GPR for measurement of the road asphalt layers thickness are presented in the paper. Main necessary improvements providing the possibility of use the GPR as a measuring device are described as well as some results of application of the GPR for inspection of the road structure after reparation the road. It was achieved accuracy of layers thickness measurement better than 0.5 cm.
Remote sensing of plane-layered media with losses using UWB signals
The previously proposed method of inverse scattering problem statement and solution for plane-layered media is extended for the media with the losses (taking into account conductivity of the medium). As before, algorithms of processing of pulse signal reflected by plane structures which was proposed by the Authors constitute the method base. The advantages of this approach are combination of the information content of the UWB pulse signals and the efficiency of algorithms for solving inverse problems. For processing and interpretation of the experimental data, the Newton-Kantorovich scheme in the frequency range is used. Using developed software, series of experiments on the processing of GPR pulse signals in sensing plane-layered medium (road pavement) is carried out. The obtained results allow to optimize values of the pulse signal parameters. Also, the obtained results can be used in biomedical research and in non-destructive testing of industrial facilities.
Effect of superficial gas velocity on the particle temperature distribution in a fluidized bed with heat production
The heat transfer behavior of particles and gas in an olefin polymerization fluidized bed was numerically analyzed using an in-house developed 3-D computational fluid dynamics discrete element model (CFD-DEM). First the implementation of the model was verified by comparing simulation results with analytical results. A constant volumetric heat production rate was implemented in the particle energy equation to mimic the heat production due to the polymerization reaction. It was found that the probability density function (PDF) of the particle temperature becomes more homogeneous with increasing superficial gas velocity. Furthermore, instantaneous snapshots of the thermal driving force (the difference between the single particle temperature and bed-average gas temperature, Tp− ) for different heat production rates provide detailed insight in the particle temperature distribution inside the fluidized bed. The time- and bed-averaged particle convective heat transfer coefficient, which was calculated by Gunn׳s correlation, was found to be independent of the superficial gas velocity. This is explained by the fact that the relative velocity of gas and particles in the emulsion phase, where most of the particles and gas interact, is hardly influenced when increasing the gas superficial velocity. From the spatial distribution of Nusselt number, it becomes apparent that the high heat transfer regions are found in the wake of rising bubbles, whereas low heat transfer rates are found in the clouds of the bubbles.