Tailored mixing inside individual droplets could be useful to ensure that reactions within microscopic discrete fluid volumes, which are used as microreactors in "digital microfluidic" applications, take place in a controlled fashion. In this paper we consider a translating spherical liquid drop to which we impose a time periodic rigid-body rotation. Such a rotation not only induces mixing via ...

We study the effect of folding ridges on the scaling properties of randomly crumpled sheets of different kinds of paper in the folded and unfolded states. We found that the mean ridge length scales with the sheet size with the scaling exponent mu determined by the competition between bending and stretching deformations in the folded sheet. This scaling determines the mass fractal dimension of r...

The transition from periodicity to chaos in a DC-DC Buck power converter is studied in this paper. The converter is controlled through a direct Pulse Width Modulation (PWM) in order to regulate the error dynamics at zero. Results show robustness with low output error and a fixed switching frequency. Furthermore, some rich dynamics appear as the constant associated with the first order error dyn...

The mechanical stretching of single polyproteins is an emerging tool for the study of protein (un)folding, chemical catalysis and polymer physics at the single molecule level. The observed processes, i.e., unfolding or reduction events, are typically considered to be stochastic and by nature are susceptible to be censored by the finite duration of the experiment. A formal analytical and experim...

The early events in protein collapse and folding are guided by the protein's elasticity. The contributions of entropic coiling and poor solvent effects like hydrophobic forces to the elastic response of proteins are currently unknown. Using molecular simulations of stretched ubiquitin in comparison with models of proteins as entropic chains, we find a surprisingly high stiffness of the protein ...

We examine the large deformation elastic response of the spectrin network in a human red blood cell (RBC) on the basis of molecular-level constitutive laws. These formulations are shown to be consistent with the predictions of continuum level models for the hyperelastic deformation of RBC, and are compared with recent experimental studies of whole-cell deformation using optical tweezers stretch...

Factors responsible for the folding of aromatic oligoamides with backbones rigidified by local three-center H-bonds were investigated. The stability of the three-center H-bonds was quantified by the half-lives of amide proton-deuterium exchange reactions, which show that the three-center H-bonds were largely intact at room temperature in the oligomer examined. This result is consistent with our...

We design a Lyapunov based boundary feedback controller for achieving mixing in a D pipe ow governed by Navier Stokes equations We show that the control law maximizes a measure of mixing that incorporates stretching and folding of material elements while at the same time minimi zing the control e ort and the sensing e ort The penalty on sensing results in a static output feedback control law ra...