Shape transformations in driven and damped molecular chains are considered. Closed chains of weak... more Shape transformations in driven and damped molecular chains are considered. Closed chains of weakly coupled molecular subunits under the action of spatially homogeneous time-periodic external field are studied. The coupling between the internal excitations and the bending degrees of freedom of the chain modifies the local bending rigidity of the chain. In the absence of driving the array takes a circular shape. When the energy pumped into the system exceeds some critical value the chain undergoes a non-equilibrium phase transition: the circular shape of the aggregate becomes unstable and the chain takes the shape of an ellipse or, in general, of a polygon. The excitation energy distribution becomes spatially nonuniform: it localizes in such places where the chain is more flat. The weak interaction of the chain with a flat surface restricts the dynamics to a flat manifold
Shape transformations in driven and damped molecular chains are considered. Closed chains of weak... more Shape transformations in driven and damped molecular chains are considered. Closed chains of weakly coupled molecular subunits under the action of spatially homogeneous time-periodic external field are studied. The coupling between the internal excitations and the bending degrees of freedom of the chain modifies the local bending rigidity of the chain. In the absence of driving the array takes a circular shape. When the energy pumped into the system exceeds some critical value the chain undergoes a nonequilibrium phase transition: The circular shape of the aggregate becomes unstable and the chain takes the shape of an ellipse or, in general, of a polygon. The excitation energy distribution becomes spatially nonuniform: It localizes in such places where the chain is more flat. The weak interaction of the chain with a flat surface restricts the dynamics to a flat manifold.
and it is a condition of accessing publications that users recognise and abide by the legal requi... more and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
ABSTRACT The role of charge-charge interactions in shape transformations of closed filaments indu... more ABSTRACT The role of charge-charge interactions in shape transformations of closed filaments induced by the charge-curvature coupling is studied. It is shown that while sufficiently strong repulsive interaction between carriers makes a circular shape of the filament energetically more favorable with a spatially uniform charge distribution along the filament, the attractive interaction facilitates a creation of polygonal filaments. The robustness of the shape transformation process with respect to external forces which are time and space periodic, is considered. It is shown that strong enough external driving makes the shape of the filament and the charge distribution along the filament highly irregular.
The motion of fluxons of the same polarity in three vertically stacked Josephson junctions is stu... more The motion of fluxons of the same polarity in three vertically stacked Josephson junctions is studied. In this configuration the difference between exterior and interior junctions plays a more important role than in other configurations with several interior junctions. Below the Swihart velocity c Ϫ , the coupling between junctions leads to a repulsion of the fluxons with the same polarity. Above this critical velocity a fluxon will induce radiation in the neighboring junctions, leading to a bunching of the fluxons in the stacked junctions. Using the Sakai-Bodin-Pedersen model, three coupled perturbed sine-Gordon equations are numerically studied for different values of coupling, damping, and bias parameters. In a narrow range of velocities bunching occurs. Outside this interval the fluxons split and new fluxons may be created. I-V characteristics are presented.
Discrete and Continuous Dynamical Systems - Series S, 2010
The dynamics of asymmetrically coupled nonlinear elements is considered. It is shown that there a... more The dynamics of asymmetrically coupled nonlinear elements is considered. It is shown that there are two distinctive regimes of oscillatory behavior of one-way nonlinearly coupled elements depending on the relaxation time and the strength of the coupling. In the subcritical regime when the relaxation time is shorter than a critical one a spatially uniform stationary state is stable. In the supercritical regime due to a Hopf bifurcation traveling waves spontaneously create and propagate along the system. Our analytical approach is in good agreement with numerical simulations of the fully nonlinear model.
The optimal-velocity follow-the-leader model is augmented with an equation that allows each drive... more The optimal-velocity follow-the-leader model is augmented with an equation that allows each driver to adjust their target headway according to the velocity difference between the driver and the car in front. In this more detailed model, which is investigated on a ring, stable and unstable multi-pulse or multi-jam solutions emerge. Analytical investigations using truncated Fourier analysis are confirmed and complemented by a detailed numerical bifurcation analysis. In addition to standard rotating waves, time-modulated waves are found.
Users may download and print one copy of any publication from the public portal for the purpose... more Users may download and print one copy of any publication from the public portal for the purpose of private study or research. You may not further distribute the material or use it for any profit-making activity or commercial gain You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
A simple phenomenological model for describing the conformational dynamics of biological macromol... more A simple phenomenological model for describing the conformational dynamics of biological macromolecules via the nonlinearity-induced instabilities is proposed. It is shown that the interaction between charges and bending degrees of freedom of closed molecular aggregates may act as drivers giving impetus to conformational dynamics of biopolymers. It is demonstrated that initially circular aggregates may undergo transformation to polygonal shapes and possible application to aggregates of bacteriochlorophyl a molecules is considered.
Sine-Gordon kink propagation in a curved planar waveguide is considered. The waveguide consists o... more Sine-Gordon kink propagation in a curved planar waveguide is considered. The waveguide consists of two rectangular regions joined by a bent section of constant curvature. Transverse homogeneous and inhomogeneous Neumann boundary conditions are used. The latter models an energy-providing mechanism for Josephson junctions of overlap type. A collective variable approach based on the kink position and the kink width depending on the transversal coordinate is developed. The latter allows to take into account both longitudinal and centrifugal forces which act on the nonlinear excitation moving in a region with finite curvature and to obtain a qualitatively good agreement with the numerical simulations. The region with finite curvature acts as a potential barrier whose height and width depend on the radius of curvature of the waveguide. The kink transmission, reflection, and trapping are investigated. The kink may be captured when a driving force, provided by a magnetic field, is applied to the kink.
The role of thermal fluctuations in the conformational dynamics of a single closed filament is st... more The role of thermal fluctuations in the conformational dynamics of a single closed filament is studied. It is shown that, due to the interaction between charges and bending degrees of freedom, initially circular chains may undergo transformation to polygonal shape.
Users may download and print one copy of any publication from the public portal for the purpose... more Users may download and print one copy of any publication from the public portal for the purpose of private study or research. You may not further distribute the material or use it for any profit-making activity or commercial gain You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
The target of the investigation is to efficiently organize the scheduling of the rubber component... more The target of the investigation is to efficiently organize the scheduling of the rubber components manufacturing of a vehicle tire production plant. A mathematical formulation followed by a computational code have to be found in order to optimize the assignment of the tasks to the machines. The complexity of the problem lies in the large number of different components to be considered together with the limitations in the compatibility between some machines and components. In addition, the production flow depends on several sequentially ordered sets of products, that comprise from grinding the raw material until manufacturing the final product ready to be assembled. Occasionally, urgent incoming demand of products can cause a sudden change in the factory environment that needs a fast answer. In this scenario, operations research tools and optimization models become crucial for calculating at any given moment a feasible solution that reaches the new constraints. A linear discrete formulation is suitable to deal with the problem. The results of the simulations clearly improving manufacturing productivity and competitiveness.
Applying pathogen reduction technologies (PRT) to platelets can extend their shelf life from 5 to... more Applying pathogen reduction technologies (PRT) to platelets can extend their shelf life from 5 to 7 days, but there have been few systematic studies of the repercussions of such technologies on outdate rates.
The role of thermal fluctuations in the conformational dynamics of a single closed filament is st... more The role of thermal fluctuations in the conformational dynamics of a single closed filament is studied. It is shown that, due to the interaction between charges and bending degrees of freedom, initially circular chains may undergo transformation to polygonal shape.
En este artículo se presenta un algoritmo para determinar las líneas paralelas de corte en un tab... more En este artículo se presenta un algoritmo para determinar las líneas paralelas de corte en un tablón irregular de madera, eliminando la capa de corteza o gema desechable y de forma que se obtenga el mayor rectángulo posible de madera útil. El algoritmo se ha traducido a lenguaje programación "c" e implementado en un microprocesador integrado a una línea de producción, de forma que su regulación sea automática y el resultado óptimo. Esta línea está compuesta por una serie de dispositivos escáner, que parametrizan los límites del tablón, las cadenas de transporte, los brazos posicionadores y finalmente la máquina serradora. El algoritmo ha sido minimizado en el número de variables y operaciones aritméticas con el propósito de optimizar el rendimiento de la memoria del microprocesador y reducir al máximo el coste computacional. La automatización de la máquina serradora proporciona una mejora en los tiempos del proceso de serrado de tablones y un mayor aprovechamiento de la madera útil.
Pseudospectral collocation methods and finite difference methods have been used for approximating... more Pseudospectral collocation methods and finite difference methods have been used for approximating an important family of soliton like solutions of the mKdV equation. These solutions present a structural instability which make difficult to approximate their evolution in long time intervals with enough accuracy. The standard numerical methods do not guarantee the convergence to the proper solution of the initial value problem and often fail by approaching solutions associated to different initial conditions. In this frame the numerical schemes that preserve the discrete invariants related to some conservation laws of this equation produce better results than the methods which only take care of a high consistency order. Pseudospectral spatial discretization appear as the most robust of the numerical methods, but finite difference schemes are useful in order to analyze the rule played by the conservation of the invariants in the convergence.
Fluxon dynamics in a system of three coupled driven damped sine-Gordon equations is investigated.... more Fluxon dynamics in a system of three coupled driven damped sine-Gordon equations is investigated. Bunching of fluxons is observed. It is shown that fluxon-fluxon-fluxon bound states exist in a certain interval of the fluxon velocity. Attraction between fluxons occurs as a result of indirect fluxon-fluxon interaction mediated by Swihart waves. To tackle the problem analytically a piece-wise linear approach is developed. The analytical approximations show good agreement with the results obtained by direct numerical simulations.
Shape transformations in driven and damped molecular chains are considered. Closed chains of weak... more Shape transformations in driven and damped molecular chains are considered. Closed chains of weakly coupled molecular subunits under the action of spatially homogeneous time-periodic external field are studied. The coupling between the internal excitations and the bending degrees of freedom of the chain modifies the local bending rigidity of the chain. In the absence of driving the array takes a circular shape. When the energy pumped into the system exceeds some critical value the chain undergoes a non-equilibrium phase transition: the circular shape of the aggregate becomes unstable and the chain takes the shape of an ellipse or, in general, of a polygon. The excitation energy distribution becomes spatially nonuniform: it localizes in such places where the chain is more flat. The weak interaction of the chain with a flat surface restricts the dynamics to a flat manifold
Shape transformations in driven and damped molecular chains are considered. Closed chains of weak... more Shape transformations in driven and damped molecular chains are considered. Closed chains of weakly coupled molecular subunits under the action of spatially homogeneous time-periodic external field are studied. The coupling between the internal excitations and the bending degrees of freedom of the chain modifies the local bending rigidity of the chain. In the absence of driving the array takes a circular shape. When the energy pumped into the system exceeds some critical value the chain undergoes a nonequilibrium phase transition: The circular shape of the aggregate becomes unstable and the chain takes the shape of an ellipse or, in general, of a polygon. The excitation energy distribution becomes spatially nonuniform: It localizes in such places where the chain is more flat. The weak interaction of the chain with a flat surface restricts the dynamics to a flat manifold.
and it is a condition of accessing publications that users recognise and abide by the legal requi... more and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
ABSTRACT The role of charge-charge interactions in shape transformations of closed filaments indu... more ABSTRACT The role of charge-charge interactions in shape transformations of closed filaments induced by the charge-curvature coupling is studied. It is shown that while sufficiently strong repulsive interaction between carriers makes a circular shape of the filament energetically more favorable with a spatially uniform charge distribution along the filament, the attractive interaction facilitates a creation of polygonal filaments. The robustness of the shape transformation process with respect to external forces which are time and space periodic, is considered. It is shown that strong enough external driving makes the shape of the filament and the charge distribution along the filament highly irregular.
The motion of fluxons of the same polarity in three vertically stacked Josephson junctions is stu... more The motion of fluxons of the same polarity in three vertically stacked Josephson junctions is studied. In this configuration the difference between exterior and interior junctions plays a more important role than in other configurations with several interior junctions. Below the Swihart velocity c Ϫ , the coupling between junctions leads to a repulsion of the fluxons with the same polarity. Above this critical velocity a fluxon will induce radiation in the neighboring junctions, leading to a bunching of the fluxons in the stacked junctions. Using the Sakai-Bodin-Pedersen model, three coupled perturbed sine-Gordon equations are numerically studied for different values of coupling, damping, and bias parameters. In a narrow range of velocities bunching occurs. Outside this interval the fluxons split and new fluxons may be created. I-V characteristics are presented.
Discrete and Continuous Dynamical Systems - Series S, 2010
The dynamics of asymmetrically coupled nonlinear elements is considered. It is shown that there a... more The dynamics of asymmetrically coupled nonlinear elements is considered. It is shown that there are two distinctive regimes of oscillatory behavior of one-way nonlinearly coupled elements depending on the relaxation time and the strength of the coupling. In the subcritical regime when the relaxation time is shorter than a critical one a spatially uniform stationary state is stable. In the supercritical regime due to a Hopf bifurcation traveling waves spontaneously create and propagate along the system. Our analytical approach is in good agreement with numerical simulations of the fully nonlinear model.
The optimal-velocity follow-the-leader model is augmented with an equation that allows each drive... more The optimal-velocity follow-the-leader model is augmented with an equation that allows each driver to adjust their target headway according to the velocity difference between the driver and the car in front. In this more detailed model, which is investigated on a ring, stable and unstable multi-pulse or multi-jam solutions emerge. Analytical investigations using truncated Fourier analysis are confirmed and complemented by a detailed numerical bifurcation analysis. In addition to standard rotating waves, time-modulated waves are found.
Users may download and print one copy of any publication from the public portal for the purpose... more Users may download and print one copy of any publication from the public portal for the purpose of private study or research. You may not further distribute the material or use it for any profit-making activity or commercial gain You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
A simple phenomenological model for describing the conformational dynamics of biological macromol... more A simple phenomenological model for describing the conformational dynamics of biological macromolecules via the nonlinearity-induced instabilities is proposed. It is shown that the interaction between charges and bending degrees of freedom of closed molecular aggregates may act as drivers giving impetus to conformational dynamics of biopolymers. It is demonstrated that initially circular aggregates may undergo transformation to polygonal shapes and possible application to aggregates of bacteriochlorophyl a molecules is considered.
Sine-Gordon kink propagation in a curved planar waveguide is considered. The waveguide consists o... more Sine-Gordon kink propagation in a curved planar waveguide is considered. The waveguide consists of two rectangular regions joined by a bent section of constant curvature. Transverse homogeneous and inhomogeneous Neumann boundary conditions are used. The latter models an energy-providing mechanism for Josephson junctions of overlap type. A collective variable approach based on the kink position and the kink width depending on the transversal coordinate is developed. The latter allows to take into account both longitudinal and centrifugal forces which act on the nonlinear excitation moving in a region with finite curvature and to obtain a qualitatively good agreement with the numerical simulations. The region with finite curvature acts as a potential barrier whose height and width depend on the radius of curvature of the waveguide. The kink transmission, reflection, and trapping are investigated. The kink may be captured when a driving force, provided by a magnetic field, is applied to the kink.
The role of thermal fluctuations in the conformational dynamics of a single closed filament is st... more The role of thermal fluctuations in the conformational dynamics of a single closed filament is studied. It is shown that, due to the interaction between charges and bending degrees of freedom, initially circular chains may undergo transformation to polygonal shape.
Users may download and print one copy of any publication from the public portal for the purpose... more Users may download and print one copy of any publication from the public portal for the purpose of private study or research. You may not further distribute the material or use it for any profit-making activity or commercial gain You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
The target of the investigation is to efficiently organize the scheduling of the rubber component... more The target of the investigation is to efficiently organize the scheduling of the rubber components manufacturing of a vehicle tire production plant. A mathematical formulation followed by a computational code have to be found in order to optimize the assignment of the tasks to the machines. The complexity of the problem lies in the large number of different components to be considered together with the limitations in the compatibility between some machines and components. In addition, the production flow depends on several sequentially ordered sets of products, that comprise from grinding the raw material until manufacturing the final product ready to be assembled. Occasionally, urgent incoming demand of products can cause a sudden change in the factory environment that needs a fast answer. In this scenario, operations research tools and optimization models become crucial for calculating at any given moment a feasible solution that reaches the new constraints. A linear discrete formulation is suitable to deal with the problem. The results of the simulations clearly improving manufacturing productivity and competitiveness.
Applying pathogen reduction technologies (PRT) to platelets can extend their shelf life from 5 to... more Applying pathogen reduction technologies (PRT) to platelets can extend their shelf life from 5 to 7 days, but there have been few systematic studies of the repercussions of such technologies on outdate rates.
The role of thermal fluctuations in the conformational dynamics of a single closed filament is st... more The role of thermal fluctuations in the conformational dynamics of a single closed filament is studied. It is shown that, due to the interaction between charges and bending degrees of freedom, initially circular chains may undergo transformation to polygonal shape.
En este artículo se presenta un algoritmo para determinar las líneas paralelas de corte en un tab... more En este artículo se presenta un algoritmo para determinar las líneas paralelas de corte en un tablón irregular de madera, eliminando la capa de corteza o gema desechable y de forma que se obtenga el mayor rectángulo posible de madera útil. El algoritmo se ha traducido a lenguaje programación "c" e implementado en un microprocesador integrado a una línea de producción, de forma que su regulación sea automática y el resultado óptimo. Esta línea está compuesta por una serie de dispositivos escáner, que parametrizan los límites del tablón, las cadenas de transporte, los brazos posicionadores y finalmente la máquina serradora. El algoritmo ha sido minimizado en el número de variables y operaciones aritméticas con el propósito de optimizar el rendimiento de la memoria del microprocesador y reducir al máximo el coste computacional. La automatización de la máquina serradora proporciona una mejora en los tiempos del proceso de serrado de tablones y un mayor aprovechamiento de la madera útil.
Pseudospectral collocation methods and finite difference methods have been used for approximating... more Pseudospectral collocation methods and finite difference methods have been used for approximating an important family of soliton like solutions of the mKdV equation. These solutions present a structural instability which make difficult to approximate their evolution in long time intervals with enough accuracy. The standard numerical methods do not guarantee the convergence to the proper solution of the initial value problem and often fail by approaching solutions associated to different initial conditions. In this frame the numerical schemes that preserve the discrete invariants related to some conservation laws of this equation produce better results than the methods which only take care of a high consistency order. Pseudospectral spatial discretization appear as the most robust of the numerical methods, but finite difference schemes are useful in order to analyze the rule played by the conservation of the invariants in the convergence.
Fluxon dynamics in a system of three coupled driven damped sine-Gordon equations is investigated.... more Fluxon dynamics in a system of three coupled driven damped sine-Gordon equations is investigated. Bunching of fluxons is observed. It is shown that fluxon-fluxon-fluxon bound states exist in a certain interval of the fluxon velocity. Attraction between fluxons occurs as a result of indirect fluxon-fluxon interaction mediated by Swihart waves. To tackle the problem analytically a piece-wise linear approach is developed. The analytical approximations show good agreement with the results obtained by direct numerical simulations.
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