Coarse-grid computation of the one-way propagation of coupled modes in a varying cross-section waveguide

2013 ◽  
Vol 133 (5) ◽  
pp. 2528-2532 ◽  
Author(s):  
Jean-Baptiste Doc ◽  
Simon Félix ◽  
Bertrand Lihoreau
2021 ◽  
Vol 9 (1) ◽  
pp. 88
Author(s):  
Marco Petti ◽  
Sara Pascolo ◽  
Silvia Bosa ◽  
Nadia Busetto

The prism of the Lignano tidal inlet was approximately constant over the last forty years, although the section width has halved. This has led to questions concerning the factors that most influence the tidal prism, and on the applicability of the well-known A–P relationship. A conceptual scheme of the sea–channel–lagoon system has been used to perform a sensitivity analysis of different parameters that characterize both the basin and the inlet cross-section. A 2D hydrodynamic model has been applied to evaluate the prism and compare it to the one derived by a static method, which is the basis of the analytical derivation of the A–P linkage. Three regimes have been found in the prism variability as a function of the basin extension: a linear static regime between prism and basin area; an asymptotic regime in which the prism depends only on the basin bottom friction; and an intermediate one. In addition, the roles of the inlet and channel sizes on the prism value have been investigated. The results, compared to the empirical relationships between the prism and the inlet cross-section, show that a variation in the cross-sectional area does not always corresponds to a change in tidal prism.


1990 ◽  
Vol 05 (24) ◽  
pp. 1983-1991 ◽  
Author(s):  
S. YU. KHLEBNIKOV ◽  
V. A. RUBAKOV ◽  
P. G. TINYAKOV

We study the total cross-section of high energy collisions in the one-instanton sector of purely bosonic theories with instantons. We find that in the limit g2 → 0, E/E sph = fixed , the leading behavior of the total cross-section is σ lot ~ exp [1/g2(−2S0 + F(E/E sph ))], where S0 is the instanton action. In the electroweak theory at E/E sph ≪ 1, the function F(E/E sph ) is determined by the gauge boson part of the instanton configuration and its explicit form is found.


Membranes ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 342
Author(s):  
Makhamet Urtenov ◽  
Vitaly Gudza ◽  
Natalia Chubyr ◽  
Inna Shkorkina

In electromembrane systems, the theoretical study of salt ion transport usually uses mathematical models of salt ion transport in the depleted diffusion layer of ion-exchange membranes. This study uses a one-dimensional mathematical model of salt ion transport in a cross-section of a desalination channel formed by anion-exchange and cation-exchange membranes, taking into account an effect of a dissociation/recombination reaction of water molecules. The reaction on the one hand leads to an overlimiting mass transfer due to the effect of exaltation of the limiting current. On the other hand, an appearance of new electric charge carriers (hydrogen and hydroxyl ions) can reduce the space charge that occurs in membranes and suppress an electroconvective mechanism of overlimiting transport. Thus, there is a problem of studying these phenomena together, taking into account their mutual influence, and this article is devoted to the solution of this problem. Theoretically, using a method of mathematical modeling and numerical research, main regularities are established; in particular, it is shown that the dissociation/recombination reaction of water molecules does not lead to the destruction of the double electric layer at the membranes, but also creates a new double electric layer in the middle of the desalination channel. Thus, the space charge and the dissociation/recombination reaction significantly affect each other and simultaneously the transport of salt ions.


1980 ◽  
Vol 58 (8) ◽  
pp. 1099-1118
Author(s):  
D. Duplain ◽  
B. Goulard

The bremsstrahlung weighted cross section σ−1, is calculated for,16O using the linked cluster expansion to introduce two-body correlations. All diagrams up to second order in the G-matrix are calculated. A particular choice is made among these diagrams which are grouped in order to preserve the normalization of the one-body density and of the two-body density. This selection of diagrams is shown to be consistent with an expansion in the number of hole-lines. The correlated value obtained in this way, σ−1 = 14.99 mb, is close to the experimental value σ−1 = 15.10 mb although the calculation might still be subject to improvement.


2015 ◽  
Vol 81 (3) ◽  
pp. 261-299 ◽  
Author(s):  
Michele Boldrin ◽  
Mariacristina De Nardi ◽  
Larry E. Jones

Abstract:The data show that an increase in government provided old-age pensions is strongly correlated with a reduction in fertility. What type of model is consistent with this finding? We explore this question using two models of fertility, the one by Barro and Becker (1989), and the one inspired by Caldwell and developed by Boldrin and Jones (2002). In the Barro and Becker model parents have children because they perceive their children’s lives as a continuation of their own. In the Boldrin and Jones’ framework parents procreate because the children care about their old parents’ utility, and thus provide them with old age transfers. The effect of increases in government provided pensions on fertility in the Barro and Becker model is very small, and inconsistent with the empirical findings. The effect on fertility in the Boldrin and Jones model is sizeable and accounts for between 55 and 65% of the observed Europe–US fertility differences both across countries and across time and over 80% of the observed variation seen in a broad cross section of countries. Another key factor affecting fertility the Boldrin and Jones model is the access to capital markets, which can account for the other half of the observed change in fertility in developed countries over the last 70 years.


1876 ◽  
Vol 24 (164-170) ◽  
pp. 1-32

When any portion of a conducting-wire which joins the two poles of a voltaic battei'y is increased in size, the resistance of the circuit is diminished and a greater current flows through the wire ; and as any increase in the cross section of any portion of the wire causes a corre­sponding increase in the current, it is clear that there is no part of the conducting-wire through which some portion of the current does not flow from the one pole to the other; and the outer boundary of such a wire will be a line of flow. A line of flow is a line drawn in a conductor which indicates at every point of it the direction of the current at that point. A portion of the conductor completely enclosed by lines of flow may be termed a tube of flow.


2012 ◽  
Vol 18 (6) ◽  
pp. 773-782 ◽  
Author(s):  
Małgorzata Meissner ◽  
Piotr Ruta

The forced vibrations of a curved-in-plane nonprismatic beam with a variable cross section and any curvature, generated by a load moving at a variable velocity are analyzed. Approximation with Chebyshev series and a generalized eigentransformation were used to solve the system of the partial differential equations describing the considered problem. The derived equations in their final form enable one to determine displacement and rotation functions for any beam. In order to verify the derived formulas the eigenproblem solution (used in the eigentransformation method) was compared with the one obtained by the finite element method.


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