Search results for "equilibrium"

Desychronization of one-parameter families of stable vector fields

2005

Given a one-parameter family of vector fields on , Fλ(x), , such that for each λ, Fλ has a global asymptotically stable equilibrium point xλ, we construct a vector field on of the form G(λ, x) = (g(λ, x), Fλ(x)) which exhibits chaotic behaviour. This result is an incursion in the inverse problem of master–slave synchronization.This paper discusses self-disorganization of parameter dependent stable vector fields. Motivations are found in applications to drug design: one way to lead an unfriendly organism to death is to destabilize its metabolism. In this paper we envisage the mathematical aspect of the question. We show that for a very stable system (one globally attracting equilibrium state…

Two-Player Noncooperative Games over a Freight Transportation Network''

2004

A game between two players acting on the same road transportation network is considered in this paper. The first player aims at minimizing the transportation costs, whereas the second player aims at maximizing her profit (or, in general, her utility) that is proportional to the flow passing through the arcs under her control. We introduce bilevel linear programming formulations for this problem. We derive conditions of existence and properties of the equilibrium points and propose an algorithm finding a local optimal solution. Finally, we present an application of the model to a real system involving trucks travelling through Europe from a Middle Eastern country.

First-order linear differential equations whose data are complex random variables: Probabilistic solution and stability analysis via densities

2022

[EN] Random initial value problems to non-homogeneous first-order linear differential equations with complex coefficients are probabilistically solved by computing the first probability density of the solution. For the sake of generality, coefficients and initial condition are assumed to be absolutely continuous complex random variables with an arbitrary joint probability density function. The probability of stability, as well as the density of the equilibrium point, are explicitly determined. The Random Variable Transformation technique is extensively utilized to conduct the overall analysis. Several examples are included to illustrate all the theoretical findings.

Restraining approach for the spurious kinematic modes in hybrid equilibrium element

2013

The present paper proposes a rigorous approach for the elimination of spurious kinematic modes in hybrid equilibrium elements, for three well known mesh patches. The approach is based on the identification of the dependent equations in the set of inter-element and boundary equilibrium equations of the sides involved in the spurious kinematic mode. Then the kinematic variables related to the dependent equations are reciprocally constrained and, by application of master slave elimination method, the set of inter-element equilibrium equations is reduced to full rank. The elastic solutions produced by means of the proposed approach verify the homogeneous, the inter-element and the boundary equi…

Equilibrium swelling properties of polyampholytic hydrogels

1996

The role of counter ions and ion dissociation in establishing the equilibrium swelling of balanced and unbalanced polyampholytic hydrogels has been investigated experimentally and theoretically. The swelling dependence on both the net charge offset and the external bath salt concentration has been examined using an acrylamide based polyampholytic hydrogels. By careful consideration of the swelling kinetics, we illustrate the effects of ion dissociation equilibria and counter ion shielding in polyampholytic hydrogels near their balance point where both polyelectrolyte and polyampholyte effects are present. The theory considers a Flory type swelling model where the Coulombic interactions betw…

Posturografía estática con pruebas dinámicas. Utilidad de los parámetros biomecánicos en la valoración del paciente vestibular

2012

[ES] Introducción y objetivos: La posturografía permite evaluar el control postural de un sujeto. En este estudio se presentan aquellos parámetros biomecánicos del sistema de posturografía empleado, que han resultado útiles para valorar funcionalmente los pacientes vestibulares de nuestra muestra. Material y métodos: De un total de 89 participantes, 59 eran sujetos sanos y 30 presentaban un trastorno vestibular periférico. Todos ellos realizaron un estudio posturográfico mediante el sistema NedSVE/IBV que combina pruebas estáticas (Romberg) y dinámicas (límites de estabilidad y control rítmico-direccional). Posteriormente se compararon las medidas halladas en uno y otro grupo. Resultados: L…

Recent trends in solar exergy and net radiation at global scale

2012

Abstract The availability during the last decades of remotely sensed images and global climatic data allow us to analyse the “Earth system” as a whole in order to develop concepts for global environmental management. This system can be considered a complex, dissipative, dynamic entity, far from thermodynamic equilibrium ( Schellnhuber, 1999 ). Energy balance has been considered for many decades to understand the functioning of ecosystems, the biosphere or the Earth planet as a whole, but it is also possible to study our planet from a thermodynamic point of view. In this letter we analyse recent trends in solar exergy and net radiation at global scale during the period 1980–2010, distinguish…

A Stackelberg-game approach to support the design of logistic terminals

2014

This paper deals with the design of logistic terminals taking Sicily, in the South of Italy, as a case study. It focuses on consolidation terminals for truckers and addresses the problem of optimising location pattern and public share in investments. This problem is solved through a Stackelberg game between the designer and the collective of road carriers. So a bilevel approach combines a system-optimum problem, at the upper level, with the carrier equilibrium problem, at the lower level. The choice behaviour of the lower-level player is simulated by a random utility model. The output of the game suggests that private companies and society should share the investments and the public contrib…

Attenuation of the Fourth Sound in Liquid Helium II via Extended Thermodymamics

2004

Studies of polyamines transport through liquid membranes with D2EHPA as a carrier.

2008

The transport of polyamines through the liquid membranes with di‐2‐ethylhexyl phosphoric acid (D2EHPA) was investigated. The study was performed in three main steps: liquid–liquid extraction (LLE), bulk liquid membrane (BLM) extraction, and supported liquid membrane (SLM) extraction. Equilibrium distribution experiments allowed determining the extraction constants and stoichiometric coefficients for each polyamine. It turned out that one amino group binds two molecules of carrier (one D2EHPA dimer) and the extractability of polyamine rises with the increase in number of function groups in the molecule. The BLM and SLM experiments showed that despite considerable differences in distribution …