Unstable periodic orbits in a chaotic meandering jet flow

We study the origin and bifurcations of typical classes of unstable periodic orbits in a jet flow that was introduced before as a kinematic model of chaotic advection, transport and mixing of passive scalars in meandering oceanic and atmospheric currents. A method to detect and locate the unstable periodic orbits and classify them by the origin and bifurcations is developed. We consider in detail period-1 and period-4 orbits playing an important role in chaotic advection. We introduce five classes of period-4 orbits: western and eastern ballistic ones, whose origin is associated with ballistic resonances of the fourth order, rotational ones, associated with rotational resonances of the second and fourth orders, and rotational-ballistic ones associated with a rotational-ballistic resonance. It is a new kind of nonlinear resonances that may occur in chaotic flow with jets and/or circulation cells. Varying the perturbation amplitude, we track out the origin and bifurcations of the orbits for each class

Analysis of fourth class plane mechanisms with structural groups of links of the second order

The use of complex plane mechanisms in processing equipment of consumer industryis increasing. The absence of a general method of kinematic research of the fourth and higher class mechanisms allows us to accentuate the relevance of work on kinematic analysis of multilink mechanisms. Purpose of the work is to develop sequence of actions for kinematic research of velocities of the link points of a fourth class complex plane mechanism using the method based on the provisions of the “Theoretical Mechanics” course on instantaneous velocity center of links of the mechanism, which have plane-parallel motion. The velocity vectors of link points of the second order fourth class structure group of complex plane mechanism are analyzed using grapho-analytical method, which provisionally modified initial mechanism has led to a class reduction of mechanism and allowed to conduct its researc

A POSSIBILITY OF ROBUST CHAOS EMERGENCE IN LORENZ-LIKE NON-AUTONOMOUS SYSTEM

Robust chaos is determined by the absence of periodic windows in bifurcationdiagrams and coexisting attractors with parameter values taken from some regions of the parameter space of a dynamical system. Reliable chaos is an important characteristic of a dynamic system when it comes to its practical application. This property ensures that the chaotic behavior of the system will not deteriorate or be adversely affected by various factors. There are many methods for creating chaotic systems that are generated by adjusting the corresponding system parameters. However, most of the proposed systems are functions of well-known discrete mappings. In view of this, in this paper we consider a continuous system that illustrates some robust chaos properties

Particle entrapment as a feedback effect

We consider a suspension of polarizable particles under the action of traveling wave dielectrophoresis (DEP) and focus on particle induced effects. In a situation where the particles are driven by the DEP force, but no external forces are exerted on the fluid, the joint motion of the particles can induce a steady fluid flow, which leads to particle entrapment. This feedback effect is proven to be non-negligible even for small volume concentration of particles.Comment: 4 pages, 4 figures, submitte

13C NMR spectroscopy of peroxide derivatives of cyclanes and cyclic peroxides

1. The13C NMR spectra of peroxide derivatives of cyclanes and cyclic peroxides have been investigated. 2. Replacement of the exocyclic OH group by OOH for saturated cyclic systems leads to a displacement of the signals from the α-carbon downfield by 13.0 ppm, while the β-carbon is displaced upfield by 4.5 ppm, without any dependence on the size or conformational structure of the rings. Replacement of the transannular 00 group by CH2CH2 or CH2O increases the shielding of the quaternary carbon adjoining it. © 1987 Plenum Publishing Corporation

Application of diaphragm crurotomy by A.G. Savinykh at the reconstruction of oesophagealintestinal anastomosis after gastrectomy

We report the analysis of the results forming esophageal-jejunal anastomosis in 19 patients with postgastrectomy syndrome after radical treatment of gastric cancer. Diaphragm crurotomy technically facilitates the formation of the anastomosis. The results of a comprehensive survey show that the healing of the esophageal-intestinal anastomosis is held by the type of primary tension in 16 (84,2%) operated patients, and in the late postoperative period shows no sign of stenosis of the anastomotic ring and the last remains elastic, performing closing function. Up to 1 year after surgery the overall quality of life in patients increased on average by 7,5% and amounted to 112,6 ± 5,1 points. Three years after surgery index tended to increase, reaching an average of 120,2 ± 4,1 points

Variability of <i>phoP/phoQ</i> and <i>rovA</i> Genes Sequences - Global Regulators of the Plague Agent Life Span

Compared are the gene sequences of the global phoP/phoQ and rovA transcription regulators in original Yersinia pestis strains of different subtypes. Detected is overall identity of the sequenced phoQ fragment and high conservatism of the rovA gene. All the plague agent strains belonging to the main subspecies have a missense mutation in phoP gene. It is a substitution of a single nucleotide G→A in the position 643 from the beginning of the gene, which causes amino-acid residue shift Gly→Ser in the position 215 in polypeptide chain of the PhopP protein, and, is a possible cause of alteration of the PhoP transcription activity in Yersinia pestis strains belonging to the main subspecies