Multipoint Model Research Articles

A multi-point receptor model for long-range transport over southern Scandinavia

A receptor-based model is described that is a hybrid between multivariate and dispersion models. The models employ daily measurements of elements and sulphur compounds from five sites in Scandinavia and the Faeroe Islands. By using several years of measurements it is assumed that variations due to different meteorological conditions for the transport from the source to the stations are averaged out and that the same mean source profiles are found on all stations. The variation in the daily concentrations at each site is used together with the mean values to establish the contribution from four main source types: long-range transport, local anthropogenic pollution, sea and soil. The measurements are divided according to transport from areas in eastern, central, western continental Europe and the United Kingdom. The models are capable of apportioning species measured at one site, but not included in the models.

A Study of Rainfall Prediction by Multi-point Time Series Model

In this paper, basic structuers of rainfall prediction models based on multi-point time series data are studied. According to medium-and meso-scales of precipitation areas, the life spans of precipitation are assumed to consist of two spans longer and shorter than eleven hours. It is concluded from studies based on multi-point data over Western Japan that the product form of regressive models for the long and short components is best. The accuracies of the prediction models for various (1-, 3- and 6-hour) lead times are shown.

Nonlinear Multi-point Modeling and Parameter Estimation of DO 28 Research Aircraft

The modeling and nonlinear parameter estimation of the DORNIER DO 28 research aircraft is a part of the special research program SFB 212 of FRG. In this paper a nonlinear multi-point model with six-degree-of-freedom for DO 28 parameter estimation is presented.The model considers not only the high nonlinearity of aircraft motion, the characteristics of the propeller engine, of the wings and of the horizontal stabilizer, but also the wind disturbances by reconstruction of a quasi-stationary windfield, the improved algorithm for thrust calculation and the necessary corrections of the measurements through flight-test-data-compatibility-check. In order to overcome the nonidentifiability of parameters, a multi-stage identification method with intermediate models is proposed. Compared with one-point model, the multi-point model can describe more accurately the aircraft motion and is more suitable for aircraft parameter estimation.

Molecular Recognition by Saccharides. Asymmetric Complexation between Bilirubin and Nucleosides

Abstract Asymmetric complexation between bilirubin (BR) and nucleosides has been studied in water (pH 10.8) by UV-vis absorption and circular dichroism (CD) spectroscopy. The complexes of BR with ribo- and deoxyribonucleosides show the plus to minus bisignated CD signals, which indicate that BR in these complexes selectively takes the (R)-helix conformation. Thymine and uracil arabinosides exhibit the oppositely signed CD spectra. A multi-point attachment model may explain the asymmetric complexation.

Analysis of acoustic scattering from fluid bodies using a multipoint source model

A moment-method solution is presented for the problem of acoustic scattering from homogeneous fluid bodies. It uses fictitious isotropic point sources to simulate both the field scattered by the body and the field inside the body and, in turn, point-matches the continuity conditions for the normal component of the velocity and for the pressure across the surface of the body. The procedure is simple to execute and is general in that bodies of arbitrary smooth shape can be handled effectively. Perfectly rigid bodies are treated as reduced cases of the general procedure. Results are given and compared with available analytic solutions, which demonstrate the very good performance of the procedure.

A stochastic discrete model for neutron transport in multiplying media

Abstract In the analysis of many reactor experiments the exploitation of the information contained in the fluctuations represents a powerful approach for estimating relevant kinetic parameters together with their corlfidence intervals. In the present paper a discrete multi-energy, multi-point stochastic reactor model is proposed in which the system is fed with the neutrons coming from poissonian sources. This generalization of the usual one-velocity, one-point stochastic reactor model allows a better treatment of actual situations. In the framework of the Kolmogorov and Dmitriev theory of the branching stochastic processes with several kinds of particles, the forward differential equation for the kernel probability generating function of the state of the system at any time is obtained. This function is then related to that concerning the neutron probability distribution in space, energy and time; moreover the link between the present stochastic approach and that resulting from the transport equation in th...

Continuous precipitation of monosized particles with a packed bed crystallizer

Dispersion models have been developed for the packed bed crystallizer which account for either single point nucleation or multipoint nucleation. Decrea the dispersion number for both the single point and the multipoint nucleation models decreases the geometric standard deviation of the particle size di At all dispersion numbers the multipoint model gives larger geometric standard deviations. Experiments were performed with various reactor geometries a rates using the hydrolysis of titanium tetraethoxide in ethanol solution. The experimental data are best fit by the multipoint nucleation model.

Twisting Invariant Factorization in Dual Resonance Model. I

We propose the factorization of multi-point dual resonance model in new basis vectors which are eigenstates of twisting transformation. In this factorization the twisting operator has a simple form, and it is easily seen that the generator of infinitesimal gauge transforma­ tion changes sign under the twisting transformation. It is easy to calculate the non-planar loop amplitudes without contribution of the spurious states in this factorization. We find that by inserting the projection operator the divergence is decreased only by one power for the non-planar loop amplitudes with even numbers of twisting operators, and the divergence is not decreased at all for the non-planar loop amplitude with odd numbers of twisting op­ erators.