Search results for "Equations of motion"
showing 3 items of 143 documents
Resonant activation in polymer translocation: new insights into the escape dynamics of molecules driven by an oscillating field
2010
The translocation of molecules across cellular membranes or through synthetic nanopores is strongly affected by thermal fluctuations. In this work we study how the dynamics of a polymer in a noisy environment changes when the translocation process is driven by an oscillating electric field. An improved version of the Rouse model for a flexible polymer has been adopted to mimic the molecular dynamics, by taking into account the harmonic interactions between adjacent monomers and the excluded-volume effect by introducing a Lennard–Jones potential between all beads. A bending recoil torque has also been included in our model. The polymer dynamics is simulated in a two-dimensional domain by num…
Approach to equilibrium of a quarkonium in a quark-gluon plasma
2018
We derive equations of motion for the reduced density matrix of a heavy quarkonium in contact with a quark-gluon plasma in thermal equilibrium. These equations allow in particular a proper treatment of the regime when the temperature of the plasma is comparable to the binding energy of the quarkonium. These equations are used to study how the quarkonium approaches equilibrium with the plasma, and we discuss the corresponding entropy increase, or free energy decrease, depending on the temperature regime. The effect of collisions can be accounted for by the generalization of the imaginary potential introduced in previous studies, and from which collision rates are derived. An important outcom…
Rocking behaviour of multi-block columns subjected to pulse-typeground motion accelerations
2016
Ancient columns, made with a variety of materials such as marble, granite, stone or masonry are an important part of theEuropean cultural heritage. In particular columns of ancient temples in Greece and Sicily which support only the architrave arecharacterized by small axial load values. This feature together with the slenderness typical of these structural members clearlyhighlights as the evaluation of the rocking behaviour is a key aspect of their safety assessment and maintenance. It has to be notedthat the rocking response of rectangular cross-sectional columns modelled as monolithic rigid elements, has been widely investigatedsince the first theoretical study carried out by Housner (19…