We study the stability and oscillation of traveling fronts in a three-component, advection-reaction biodegradation model. The three components are pollutant, nutrient , and bacteria concentrations. Under an explicit condition on the biomass growth and decay coeecients, we derive reduced, two-component, semilinear hyperbolic models through a relaxation procedure, during which biomass is slaved t...

We study a finite-dimensional monotone system coupled to a slowly evolving scalar differential equation which provides a negative feedback to the monotone system. We use a theory of multivalued characteristics to show that this system admits a relaxation periodic orbit if a simple model system in R does. Our construction can be used to prove the existence of periodic orbits in slow-fast systems...

Airway relaxation in response to isoprenaline, sodium nitroprusside (SNP) and electrical field stimulation (EFS) was compared under static and dynamic conditions. The capacity of relaxants to reduce airway stiffness and, thus, potentially contribute to bronchodilation was also investigated. Relaxation responses were recorded in fluid filled bronchial segments from pigs under static conditions a...

We demonstrate that magnetic oscillations of a current-biased magnetic nanocontact can be parametrically excited by a microwave field applied at twice the resonant frequency of the oscillation. The threshold microwave amplitude for the onset of the oscillation decreases with increasing bias current, and vanishes at the transition to the auto-oscillation regime. Theoretical analysis shows that m...

In this work, the compatibility and crystallinity of low density polyethylene (LDPE) and polybutene-1 (PB-1) blends were studied. Various blends of LDPE/PB-1 containing 5, 10 and 20 wt.% PB-1 were prepared in a corotating twin-screw extruder and characterized by scanning electron microscopy (SEM), shear oscillation rheology and wide-angle X-ray diffractometry (WAXD). A matrix-droplet morphology...