نتایج جستجو برای: dispersion model
تعداد نتایج: 2152860 فیلتر نتایج به سال:
On the basis of a highly simplified model for small scale structure in the electron density distribution in the Galaxy, we argue that the spread of expectation values for the dispersion measure at given distance is proportional to the square root of the dispersion measure as found from a smooth model for the electron distribution. We show that this simple method leads to appreciable improvement...
The study presents the development of an integrated model that optimises the performances of Neural Nets (NN) and dispersion models developed by the authors. Supervised NN models and dispersion models are two important techniques for evaluating air pollution concentrations. In our work we filter the concentration levels produced by an air pollution model with an NN to account for disagreement b...
Shear-wave velocity ( ) is an important parameter used for site characterization in geotechnical engineering. However, dispersion curve inversion is challenging for most inversion methods due to its high non-linearity and mix-determined trait. In order to overcome these problems, in this study, a joint inversion strategy is proposed based on the particle swarm optimization (PSO) algorithm. The ...
While Poisson regression is a popular tool for modeling count data, it is limited by its associated model assumptions. One assumption is that the response variable follows a Poisson distribution. However, overor under-dispersion are common in practice and are not accommodated by Poisson regression. In addition, the dispersion is assumed fixed across observations, whereas in practice dispersion ...
Dispersion is the spreading of refracted light into its component colors or spectrum. A model of refraction including dispersion is developed using the techniques of distributed ray tracing. Two models of the rainbow, one empirical or impressiOniStiC, the other purely physical, are developed using the results of the dispersion model. The problem of representing the spectrum of monochromatic col...
Under the effects of electric field and chemical reaction, a mathematical model has been developed to study the dispersion of aerosols in a couple stress fluid flowing through a channel which is analytically solved using Taylor disper¬sion model. The solutions for velocity, concentration distribution and dispersion coefficient are numerically computed and the results are represented graphically...
abstract the present study was conducted to investigate the effect of using model essays on the development of writing proficiency of iranian pre-intermediate efl learners. to fulfill the purpose of the study, 55 pre- intermediate learners of parsa language institute were chosen by means of administering proficiency test. based on the results of the pretest, two matched groups, one as the expe...
an experimental study has been made of the hydrodynamics of a stage mixer-settler to obtain appropriate design information. in this paper several tests were done according to full factorial design of experiments with high reliability, since each test recurs seven times and the results of them are very close to each other(p=1bar and t=25 °c). sauter diameter in each test is determined with phot...
We analyze the dispersive properties of inhomogeneous nanostructures (INSs) composed of alternating layers of different materials. Analysis of the interaction between the propagating pulse and the INS provides modified dispersion characteristics. An approximate theoretical model predicting the dispersion properties of the INS is developed and compared with more accurate numeric computation resu...
We present an exact expression for the upscaled dynamic dispersion coefficient (D) for one-dimensional transport by Hagen-Poiseuille flow which is the basis for modeling transport in porous media idealized as capillary tubes. The theoretical model is validated by comparing the breakthrough curves (BTCs) from a 1D advection-dispersion model with dynamic D to that from direct numerical solutions ...
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