We study the three-timescale dynamics of a model that describes El Niño Southern Oscillation (ENSO) phenomenon, which was proposed in Roberts et al. (2016). While ENSO phenomena are inherently characterised by presence multiple distinct timescales, above has previously been studied two-timescale context only. Here, we uncover geometric mechanisms responsible for complex oscillatory regime, and ...

The paper deals with the study of the features of oscillatory processes in the electrocatalytic reaction mechanism underlying the electrochemical reactor. The conditions for the existence of several types of oscillations (small amplitude harmonic oscillations, relaxation oscillations and oscillations of transitional type) is obtained.

For the understanding of planetary and stellar dynamos an overview of the major parameter dependences of convection driven dynamos in rotating spherical fluid shells is desirable. Although the computationally accessible parameter space is limited, earlier work is extended with emphasis on higher Prandtl numbers and uniform heat flux condition at the outer boundary. The transition from dynamos d...

Asymptotic methods for singularly perturbed delay differential equations are in many ways more challenging to implement than for ordinary differential equations. In this paper, four examples of delayed systems which occur in practical models are considered: the delayed recruitment equation, relaxation oscillations in stem cell control, the delayed logistic equation, and density wave oscillation...

We report the observation of ultrahigh frequency oscillations of up to 240 GHz in optically gain switched vertical cavity surface emitting lasers. These oscillations are shown to be produced by multimode emission through mode competition ~10–30 GHz! or mode beating ~above 100 GHz!. Although these oscillations are not related to the intrinsic modulation bandwidth, some of them could be mistaken ...

Abstract: Studied is a flow between two infinite planes, one of which performs periodic oscillations. Non-Newtonian fluid is described by the Voight-Oldroyd model applicable for the motion of an emulsion of one liquid in another. Such liquid possesses relaxation properties, which give rise to a relaxation wave. The generated results may be used to determine viscosity and the relaxation constant...

This paper employs a molecular dynamics approach to uncover the time profile of exciton formation, which can be divided into two stages: localization of electron-hole pairs and relaxation process (nuclear and electronic). Under photoexcitation, an electron-hole pair is formed by an electronic transition, and the pair in turn becomes localized through the electron-lattice interaction, which trig...

A stack with a small critical temperature gradient is desirable for a standing wave thermoacoustic engine to obtain a low onset temperature difference (the minimum temperature difference to start engine’s self-oscillation). The viscous and heat relaxation loss in the stack determines the critical temperature gradient. In this work, a dimensionless critical temperature gradient factor is obtaine...

In the last 50 years several studies have been made to understand the relaxation mechanisms of the heavy interstitial atoms present in transition metals and their alloys. Internal friction measurements have been carried out in a Nb–Ti alloy containing 3.1 at.% of Ti produced by the Materials Department of Chemical Engineering Faculty of Lorena (Brazil), with several quantities of oxygen in soli...

We describe application of spectral analysis of laser Doppler flowmetry (LDF) signals to investigation of cerebrovascular haemodynamics in patients with post-acute ischemic stroke (AIS) and cerebrovascular insufficiency. LDF was performed from 3 to 7 days after the onset of AIS on forehead in the right and left supraorbital regions in patients. Analysis of LDF signals showed that perfusion in t...