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The surface charges on hematite, kaolinite and on kaolinite coated with hematite (kaolinite-hematite system) were measured and successfully described using the model (Four-Layer Model) developed by Bowden and co-workers (1977; 1980a; 1980b). The surface charge was also calculated theoretically, according to a computer program developed by Barrow (1987). Significant differences were pointed out for the surface properties of the three solids examined. Anion-specific adsorption was observed for hematite and kaolinite-hematite, and cation adsorption for kaolinite.

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A simple model of light diffuse reflectance in thin skin fruits is presented. The model is based in a semi-infinite two-layer geometry (skin and flesh) and introduces simplifications due to the fact that the first layer is very thin. The flesh is described in terms of the usual reduced scattering and absorption coefficients µs′ and µa but the skin is modeled by simple reflection (R), absorption (A) and transmission (T) coefficients. The problem of diffuse reflectance is thus reduced to the problem of determining the four constants µs′, µa, R and T. It is shown that the problem can be solved by using absolute reflectance and spatially resolved reflectance measurements simultaneously. The coefficients µs′ and µa are determined by the usual fit of the diffuse reflectance profile (photons re-emitted from the flesh far from the incidence point) to the diffusion approximation. The coefficients R and T are determined by a second fit involving the total reflectance profile (photons reemitted both from skin and flesh), the incident beam profile and the diffuse reflectance profile calculated according to the previously determined values of µs′ and µa. The anisotropy of the light re-emitted by the fruit can also be roughly compared with the Lambertian expected behavior. In order to test the model we have followed a population of 22 ‘Rocha’ pears along a period of two weeks. We have then performed the population averages along the time and checked the plausibility of the values obtained for µs′, µa, R and T according to the expected fruit physiological changes along ripening. The results show that all parameters are physically acceptable and evolve in time according to the expected fruit ripening physiology.

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This five-layered model consisting of 180 neurons is aimed at simulating some elementary functions of primary visual cortex of mammals in form detection. Its main achievements are: 1. Detection of points, lines, simple geometric figures in the V1 2. Abstraction of 19 different qualities of geometric figures 3. Simulation and rational explanation of processing of peripheral stimuli in the V1, explanation of mechanism of origin of visual ERPs, including P300 wave 4. Simulation and explanation of the nature and build up of the cognitive function within V1 and its possible relation to long-term memory 5. The model is based partly on Hebb-type synapses, illustrates the role of neuronal assemblies, sheds light on the functional relationship of excitatory and inhibitory neurons, in their conformity with special tasks of different cortical layers.

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two layer model of soil hydrology. Boundary Layer Meteorology. 29 . 1--20. A two layer model of soil hydrology. Boundary Layer Meteorology. 29

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–945. Laza B., 2010. A planetáris határréteg és a talaj hidrofizikai tulajdonságai közötti kapcsolat vizsgálata az MM5 modellel. BSc szakdolgozat. Budapest. Mahrt, L. & Pan, H. L., 1984. A two-layer model of soil hydrology. Bound

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