Papers by Keyword: Inversion

Abstract: Particulate flow is commonly encountered in industries as well as in many other chemical and mechanical engineering applications. The accurate measurement of particle size distribution is of the utmost importance since it decides the physical and chemical characteristic of the particles. The light extinction method can be used for in-line monitoring of particle systems thus providing real time measurements of both particle size distribution and particle concentration. In light extinction particle sizing, a classification inversion algorithm is proposed for the circular cylinder particles. The measured circular cylinder particle system is inversed with different particle distribution functions and classified according to the inversion errors in the dependent model. The simulation experiments illustrate that it is feasible to use the inversion errors of object functions to inverse the circular cylinder particle size distribution in the light extinction particle sizing technique. This classing inversion algorithm can avoid the defects that the type of the size distribution must be assumed beforehand for the light extinction method.

Abstract: In the mass concrete structure construction, the thermal insulation material and cooling pipe are important temperature control materials to prevent concrete from cracking. In order to select the right materials, their heat exchange coefficients should be obtained exactly. But no proper apparatus can give the parameters through simple measure. An experiment concrete block with the dimension of 50m long and 22m wide was established near a dam construction site and the corresponding inversion calculating was applied. The experiment method is presented. The measured curves and calculated curves meet well which shows the inversed parameters reliable. Then the heat exchange coefficients of the EPE insulation materials with different thickness and the HDPE pipes with different diameters are given. The application effect shows the selected materials have achieved the goal of crack prevention. The experiment and inversion method will provide reference to other cases and the heat exchange coefficients can be used in similar structures.

Abstract: Focus on the topography features of V-shaped deep river valley in Ada dam area, the influence of intensively, moderately and slightly weathered stratum as well as the action of river valley erosion on geostress field was considered. Then, the 3-D initial geostress unloading model was established based on the measured geostress data and geological conditions. Combining the finite element numerical method and inversion theory, multiple regression analysis was established between the measured and corresponding calculated results of geostress. Then, the optimal regression coefficient could be derived. In addition, for convenience of comparison, another method was adopted by ignoring the action of river valley erosion. Through the comparison between the computed values by two methods and the measured geostress values respectively, it is found that the computed values by the former method are more close to the measured ones. Therefore, the distribution rule of initial geostress field can be obtained accurately, which provides important reference for design and construction of Ada dam and its diversion tunnel layout.

Abstract: Microtremors was developed to inverse S-wave velocity structure of sites because it costs little and easy to monitor, can be performed at any place even in a densely populated city with non-destructive measurements, the genetic algorithm is widely used in inversion and there are many disadvantages in using genetic algorithms to solve practical problems, so the authors did a lot of efforts to overcome these disadvantages. In order to solve these disadvantages, a coarse-grained parallel genetic algorithm(PGA) based on personal computer cluster was proposed to inverse S-wave velocity structure of shallow soil layer of actual engineering sites, the simulated annealing algorithm and parallel technique message passing interface(MPI) were adopted to implement the coarse-grained parallel compute. The subpopulations were collaboratively optimized through individual migration strategy and the dynamic populations were adopted to balance the computing load. The shallow S-wave velocity structures of two examples and the actual engineering sites were inversed through a 4-node PC cluster test system, the results showed that the algorithm has a good parallel efficiency and can be used in engineering site.

Abstract: In order to design a set of geostationary meteorological satellite data processing system，which have common data processing，practical remote sensing products and rich visual stylet，used VC++6.0 MFC and dynamic link library and the mature remote sensing products processing algorithms, to design it. Multi-satellite source geostationary meteorological satellite data are integrated, remote sensing products are generated, for example, cloud detection, cloud classification, cloud top height. The original cloud image, remote sensing and geographic information products are displayed vividly. The three-dimensional cloud image processing retrieval based on cloud detection product takes into account the visual effect, and also has a clear physical meaning, practicality is strong. The system makes geostationary meteorological satellite information play a more important role in the current weather forecast.

Abstract: The reinforced concrete single T-shaped beam is of common use. Compared with mechanical analysis, little attraction has been put on the stochastic optimized inversion problem. The present study is aimed to carry out stochastic optimized inversion of mechanical parameters of reinforced concrete single T-shaped beam based on degraded solid element theory. Firstly for the reinforced concrete single T-shaped beam, degraded solid element theory is deduced and the displacement function is obtained. Then Gaussian error function of mechanical parameters of the reinforced concrete single T-shaped beam is founded and the corresponding formulas of Gaussian expectation and variance are derived. The stochastic optimized inversion computing formulas are also obtained by adopting optimization method including conjugate gradient method. Then the steps of stochastic Gaussian optimized inversion of mechanical parameters of the reinforced concrete single T-shaped beam are listed. Through analysis of a classic example, some important conclusions about stochastic Gaussian optimized inversion of mechanical parameters of the reinforced concrete single T-shaped beam are drawn.

Abstract: Application of topological graphs to analyze and synthesize planetary gear trains (PGTs) is an effective approach in searching for innovative planetary trains. Two topological graphs of basic structure and three fundamental units of PGTs are established as the basis of topological synthesis. Then combination system of PGTs are summarized based on stratify-cation, which can be classified as four basic type including series, parallel, separate and close. Several kinds of compound combination are also discussed. The variation law of topological graphs are analyzed and sorted as diversification including evolution, regression, decay and recovery and inversion transforming graphs to PGTs. Finally graph library based on variation law is presented as a simple and practical way to create a great number of new PGTs.

Abstract: The measurement and analysis system of nanoparticles size distribution was developed by using virtual instrument technology, while the photon counting technology was applied in the system to replace the expensive correlator. High speed photon pulse counter was designed. The real-time data of nanoparticles dynamic light scattering were analyzed in the mixed program of MATLAB and LabVIEW, where the time autocorrelation functions of nanoparticles light scattering signals of monodisperse and polydisperse are reversed by NNLS arithmetic. Experiments results show that the peak position, peak width and symmetry of inverse distribution are very close to the real simulate particles.

Abstract: In the mountains area, we have to solve the problem that how to select appropriate method, accurately and effectively explore the burial condition and location of the deep mineral ore with complex terrain. Advanced and Convenient high-frequency magnetotelluric (HF-MT) sounding system Stratagem EH- 4 was applied to electromagnetic array profile survey in target mining area of northern Guangxi. Bostick and Rapid Relaxation Iterative inversion method were used to interpret the observational data, and it has been verified by the mine works that location of faults and orebodies marked by resulting images are tally with the real geological conditions, which provide resource base for the continued production of the mine. This measurement technique and interpretation method should be popularized and applied in mineral resources exploration, especially in mountains area.

Abstract: In order to improve machining accuracy and surface quality effectively in ECM (electrochemical machining), a novel pulse inversion power supply has been presented, which has following merits such as high-frequency short pulse, high-power, and compact size. The scheme of full bridge inversion has been selected in this power supply model, and feedback circuit realizes voltage adjusted automatically, and guarantees to stability of voltage. Protect circuit has designed to avoid the problem of workpiece-burn. Finally, a series of electrochemical mechanical polishing tests using the power supply have been carried out, and the results have proved that it helps to achieve well surface quality processed, and improve machining accuracy, and also verify feasibility of its scheme.