Search results for "CONST"

On the influence of lower order terms for propagation of analytic singularities for operators with constant coefficients

1988

Stress-Strain Law for Confined Concrete with Hardening or Softening Behavior

2013

This paper provides a new general stress-strain law for concrete confined by steel, fiber reinforced polymer (FRP), or fiber reinforced cementitious matrix (FRCM), obtained by a suitable modification of the well-known Sargin’s curve for steel confined concrete. The proposed law is able to reproduce stress-strain curve of any shape, having both hardening or softening behavior, by using a single closed-form simple algebraic expression with constant coefficients. The coefficients are defined on the basis of the stress and the tangent modulus of the confined concrete in three characteristic points of the curve, thus being related to physical meaningful parameters. It will be shown that if the v…

The exact finite‐difference scheme for vector boundary‐value problems with piece‐wise constant coefficients

1998

We will consider the exact finite‐difference scheme for solving the system of differential equations of second order with piece‐wise constant coefficients. It is well‐known, that the presence of large parameters at first order derivatives or small parameters at second order derivatives in the system of hydrodynamics and magnetohydrodynamics (MHD) equations (large Reynolds, Hartmann and others numbers) causes additional difficulties for the applications of general classical numerical methods. Thus, important to work out special methods of solution, the so‐called uniform converging computational methods. This gives a basis for the development of special monotone finite vector‐difference schem…

The edge-of-the-wedge theorem for systems of constant coefficient partial differential operators. I

1988

On demontre des resultats sur l'extendabilite holomorphe des fonctions holomorphes definies sur deux coins ou plus et pour lesquelles la somme des valeurs limites s'annulent

Anharmonicity deformation and curvature in supersymmetric potentials

1994

An algebraic description of the class of 1D supersymmetric shape invariant potentials is investigated in terms of the shape-invariant-potential (SIP) deformed algebra, the generators of which act both on the dynamical variable and on the parameters of the potentials. The phase space geometry associated with SIP's is studied by means of a coherent state (SIP-CS) path integral and the ray metric of the SIP-CS manifold. The anharmonicity of SIP's results in a inhomogeneous phase space manifold with one Killing vector and with a modified symplectic Kahler structure, and it induces a non constant curvature into the generalized phase space. Analogous results from the phase space geometry of someq…

Riemann’s Result and Consequences for Physics and Philosophy

2020

Riemann commented on his main result as follows: “The common character of those manifolds whose curvature is constant may also be expressed thus: that figures may be viewed in them without stretching. For clearly figures could not be arbitrarily shifted and turned around in them if the curvature at each point were not the same in all directions at one point as at another, and consequently the same constructions can be made from it; whence it follows that in aggregates with constant curvature, figures may have any arbitrary position given them. The measure-relations of these manifolds depend only on the value of the curvature, and in relation to the analytic expression it may be remarked tha…

Correction of the deviations in the retention times with Chromolith columns associated to the flow rate: Implications in the modelling of the retenti…

2011

In a previous work (J. Sep. Sci. 2009, 32, 2793-2803), we reported an interpretive optimisation approach to achieve maximal resolution in minimal analysis time, based on models describing the retention and peak shape as a function of mobile phase composition and flow rate. The method was applied to the separation of a group of basic drugs in a Chromolith column. In that work, we found that the retention factors were sensitive to the flow rate. The reason of the observed deviations in retention times is the increase in the column volume at the applied pressure, which decreases the linear velocity inside the column. This behaviour forced to include a correction term in the model that describe…

A new mathematical tool for an exact treatment of open quantum system dynamics

2005

A new method to obtain an operatorial exact solution of a wide class of Markovian master equations is presented. Its key point is the existence of a constant of motion partitioning the Hilbert space into finite-dimensional subspaces. The consequent possibility of representing the reduced density operator as a block diagonal matrix is shown. Each “block operator” evolves under the action of a non-unitary operator explicitly derived. Our mathematical approach is illustrated applying it to simple physical systems.

Chemotaxis and Haptotaxis on Cellular Level

2018

Chemotaxis and haptotaxis have been a main theme in the macroscopic study of bacterial and cellular motility. In this work, we use a successful model that describes cellular motility and investigate the influence these processes have on the shape and motility of fast migrating cells. We note that, despite the biological and modelling differences of chemotaxis and haptotaxis, the cells exhibit many similarities in their migration. In particular, after an initial adjustment phase, the cells obtain a stable shape, similar in both cases, and move with constant velocity.

Constantine X Doukas (1059–1067) versus Uzes – about the Nomads on Boats on the Danube in 1064

2021

The reign of the Doukas dynasty in 1059–1078 was a time when new threats to the Byzantine Empire emerge in Europe and Asia. One of them was the increased activity of Turkmen who were penetrating the lands belonging to the Byzantines. A manifestation of these threats was visible during the rule of Constantine X Doukas (1059–1067) in 1064. We have there an invasion of the tribe of Uzes, who crossed the Danube. They ventured so far, as the vicinity of Thessalonica and the province of Hellas, plundering everything in their path. Their actions surprised the defense of the Byzantines. This attack on the empire was related to their crossing of the Danube, about which Michael Attaliates and Skylitz…