Formation Of Dissipative Structures Research Articles

Dissipation-Assisted Coherence Formation in a Spinor Quantum Gas.

We report the formation of magnetic eigenstates assisted by naturally occurring particle dissipation in a Bose-Einstein condensate of spin-2 ^{87}Rb atoms. Although the atomic interaction energetically favors the nonferromagnetic state, we observed the spontaneous evolution of an unpolarized spin state into the transverse ferromagnetic state. Under such dynamics, the spin-dependent dissipation of atoms enhances the synchronization of the relative phases among five magnetic sublevels to promote magnetization. Through numerical simulations based on mean-field theory, we show that another exotic magnetic eigenstate, the cyclic state, can also be formed through the spin-dependent dissipation of atoms.

Frequency comb generation through the locking of domain walls in doubly resonant dispersive optical parametric oscillators.

In this Letter we theoretically investigate the formation of localized temporal dissipative structures, and their corresponding frequency combs in doubly resonant dispersive optical parametric oscillators. We derive a nonlocal mean field model, and show that domain wall locking allows for the formation of stable coherent optical frequency combs.

The Influence of Brominated UHMWPE on the Tribological Characteristics and Wear of Polymeric Nanocomposites Based on UHMWPE and Nanoparticles

Tribological tests of polymeric composite materials based on UHMWPE modified with inorganic nanoparticles and brominated UHMWPE as a functional alloying element have been performed in order to establish their effect on the interphase interactions in a UHMWPE/nanoparticles system. The wear resistance of the polymer with brominated UHMWPE is shown to be 8–10 times higher than that of the initial polymer, most likely due to the formation of dissipative structures on the polymer surface, which are formed by the chemical and adhesive cross-linking of nanoparticles and tribodecay products.

From the Lugiato-Lefever equation to microresonator-based soliton Kerr frequency combs.

The model, that is usually called the Lugiato-Lefever equation (LLE), was introduced in 1987 with the aim of providing a paradigm for dissipative structure and pattern formation in nonlinear optics. This model, describing a driven, detuned and damped nonlinear Schroedinger equation, gives rise to dissipative spatial and temporal solitons. Recently, the rather idealized conditions, assumed in the LLE, have materialized in the form of continuous wave driven optical microresonators, with the discovery of temporal dissipative Kerr solitons (DKS). These experiments have revealed that the LLE is a perfect and exact description of Kerr frequency combs-first observed in 2007, i.e. 20 years after the original formulation of the LLE-and in particular describe soliton states. Observed to spontaneously form in Kerr frequency combs in crystalline microresonators in 2013, such DKS are preferred state of operation, offering coherent and broadband optical frequency combs, whose bandwidth can be extended exploiting soliton-induced broadening phenomena. Combined with the ability to miniaturize and integrate on-chip, microresonator-based soliton Kerr frequency combs have already found applications in self-referenced frequency combs, dual-comb spectroscopy, frequency synthesis, low noise microwave generation, laser frequency ranging, and astrophysical spectrometer calibration, and have the potential to make comb technology ubiquitous. As such, pattern formation in driven, dissipative nonlinear optical systems is becoming the central Physics of soliton micro-comb technology.This article is part of the theme issue 'Dissipative structures in matter out of equilibrium: from chemistry, photonics and biology (part 2)'.

Influence of cadmium on oxidative stress and NADH oscillations in mussel mitochondria

Biological organisms evolved to take advantage of recurring environmental factors which enabled them to assimilate and process metabolic energy for survival. Mitochondria display non-linear oscillations in NADH levels (i.e. wave behavior) that result from the balance between NADH production (aerobic glycolysis) and oxidation for ATP synthesis. The purpose of this study was to examine the effects of cadmium (Cd) on mitochondrial NADH oscillations in quagga mussels Dreissena bugensis exposed to 50 and 100 μg/L CdCl2 for 7 days at 15 °C. Metallothionein (MT) levels, thioredoxin reductase (TrxR) activity and NADH oxidation rate were also determined, as were oscillations in NADH and the formation of dissipative structures (turbidity), in isolated mitochondria suspensions. The results show that exposure to Cd readily induced MT levels at both concentrations tested and that TrxR and NADH oxidase activity was induced at 100 μg/L Cd only. In control mussels, NADH levels oscillated in mitochondria suspensions with a natural period of 2 to 2.5 min for up to 40 min. Exposure to Cd increased the complexity of the frequency profile of NADH oscillations and reduced the amplitudes of the natural signal with a period of 2 to 2.5 min. The formation of dissipative structures decreased in response to a Cd concentration of 100 μg/L but increased at a level of 50 μg/L. The amplitudes at the natural frequency were significantly correlated with NADH oxidase activity (r = −0.91) and with the formation of dissipative structures (r = −0.59). We conclude that Cd could alter the natural frequency in oscillations of NADH in mitochondria, thereby contributing to an increase in NADH oxidation rate and disruption of the spatial organization of mitochondria in suspension. In conclusion, changes in the wave behavior of NADH in mitochondria are proposed as a novel biomarker of toxicity in aquatic organisms.

ABOUT THE PRE-OUTBURST STATE OF THE COAL AND SANDSTONE AND THE POSSIBLE MECHANISM OF COAL AND GAS OUTBURST PROCESS

The paper aims to examine the suitability of A. S. Balankin brittle fracture criterion in predicting the of large-scale coal and gas outbursts in underground coal mines under compression load. Formation of dissipative structures as cracks and clusters of local microcracking occurs under the influence of the rock pressure. The formation of microdefects in dissipative structures occurs mainly on local anisotropic inclusions. Mechanism of pre-outburst spalling of gas-saturated coal is analyzed. Destruction (primary outburst) occurs when the brittle fracture conditions are met. And also in the case of such a ratio of “coal seam thickness – the size of micro defects aggregations”, which provides reduction in coal strength to a minimum. Further destruction occurs by known scenario.

Mathematical Simulation of Low-Frequency Mechanical Action on Bimolecular Reaction Kinetics in a Structured Liquid

A mathematical model of the physicochemical processes that occur under low-frequency mechanical action on bimolecular reaction kinetics with consideration for the association of reagents is presented. As a result of the mathematical simulation, special features of the kinetics and stability of the reaction modes were established. It was shown that, in a structured liquid, a formally simple reaction occurs as a complex process with the appearance of bistability regimes, the formation of a temporal dissipative structure, and the complex structure of intermediate concentration oscillations. The possibility of controlling transitions from stable to unstable reaction conditions and vice versa under changes in the external action amplitude was demonstrated.

A taxonomy of optical dissipative structures in whispering-gallery mode resonators with Kerr nonlinearity.

In this paper, the research related to the formation of optical dissipative structures in Kerr-nonlinear whispering-gallery mode resonators pumped with continuous-wave lasers is reviewed. Pattern formation in these systems can be analysed using the paradigmatic Lugiato-Lefever model, which is a partial differential equation ruling the dynamics of the intra-cavity laser field. Various dissipative structures such as Turing rolls, solitons, breathers and spatio-temporal chaos can emerge in the resonator depending on the laser power and frequency. The bifurcation analysis enables a classification of these patterns, and also permits identification of their basins of attraction.This article is part of the theme issue 'Dissipative structures in matter out of equilibrium: from chemistry, photonics and biology (part 1)'.

Formation of Dissipative Structures in an Amorphous Film

The formation of nanothin spatial dissipative structures (SDSs) of hexagonal selenium with elastic rotational curvature of the lattice about [001] in an amorphous film was considered. It was established that nanothin SDSs form in thermal gradient treatment of an amorphous film by one-side heating of its lower surface at T = 453 K. The state of pseudo-single crystal, which precedes the formation of a nanothin SDS in an amorphous film, is a state with a high concentration of vacancies. Under the action of the temperature difference ΔT, vacancies and selenium atoms undergo thermal diffusion in the direction perpendicular to the surface of the pseudo-single crystal. It was shown that, when ΔT reaches critical values, there is a transition from the structure of a pseudo-single crystal to the structure of a rhombic nanothin SDS of hexagonal selenium. The heat flux through the nanothin SDS in the direction perpendicular to its surface ensures the entropy export to the environment. After the thermal gradient treatment of the amorphous film, the nanothin SDS is quenched by cooling it in air; in this process, there is quenching of nonequilibrium structural defects—atoms and vacancies displaced from equilibrium positions. The quenching makes the nanothin SDS stable. The formation of nanothin SDSs of hexagonal selenium with elastic rotational curvature of the lattice about [001] in an amorphous film occurs under conditions satisfying the theory of the formation of dissipative structures.

Justification of the mathematical (thermodynamic) model of deformation processes in the materials cutting system

By the cutting system we mean the workpiece, shavings and the cutting tools that are in the conditions of contact interaction. In this system occur: the destruction of the material; elastic and plastic deformation; the formation of a new surface; electric and magnetic polarization of the surface layers; mechanical interaction of components of the cutting system, accompanied by internal and external friction; heat exchange between the components of the cutting system, which involves all the existing methods of heat transfer in nature (convection, heat conductivity, radiation); the withdrawal of energy from the system, accompanied by the formation of so-called dissipative structures. The authors propose a mathematical model developed using the thermodynamic theory, which takes into account the mutual transformation of energy in the system. To describe highly nonequilibrium processes, it is necessary to determine not only the state of the system at one time or another, but also be able to calculate the irreversible energy flows (the flux of the released elastic energy, the work flow of destruction, the mass flow, etc.), through which it is possible to trace changes, occurring in the cutting system.

Synergy and Self-organization in Tribosystem’s evolution. Energy Model of Friction

Different approaches are known to treat self-organization in tribosystems, related to the structural adaptation in the formation of dissipative surface structures and of frictional or tribo-films, using of synergistic modifying of layers and coatings, e.g. of the selective material transfer during friction, etc. Regarding tribological processes in contact systems, self-organization is observed as spontaneous creation of higher ordered structures during the contact interaction. The proposed paper considers friction as process of transformation and dissipation of energy and process of elasto-plastic deformation localized in thin surface layers of the interacting bodies. Еnergetic interpretation of friction is proposed. Based on the energy balance equations of friction, the evolution of tribosystems is followed in its adaptive-dissipative character. It reflects the variable friction surfaces compatibility and the nonlinear dynamics of friction evolution. Structural-energy relationships in the contacting surfaces evolution are obtained. Maximum of tribosystem’s efficiency during the evolution is the stage of self-organzation of the friction surface layers, which is a state of abnormal low friction and wear.

Dissipative structures, machines, and organisms: A perspective.

Self-organization in nonequilibrium systems resulting in the formation of dissipative structures has been studied in a variety of systems, most prominently in chemical systems. We present a study of a voltage-driven dissipative structure consisting of conducting beads immersed in a viscous medium of oil. In this simple system, we observed remarkably complex organism-like behavior. The dissipative structure consists of a tree structure that spontaneously forms and moves like a worm and exhibits many features characteristic of living organisms. The complex motion of the beads driven by the applied field, the dipole-dipole interaction between the beads, and the hydrodynamic flow of the viscous medium result in a time evolution of the tree structure towards states of lower resistance or higher dissipation and thus higher rates of entropy production. The resulting end-directed evolution manifests as the tree moving to locations seeking higher current, the current that sustains its structure and dynamics. The study of end-directed evolution in the dissipative structure gives us a means to distinguish the fundamental difference between machines and organisms and opens a path for the formulation of physics of organisms.

ON FRACTURING OF BRITTLE AND DUCTILE ROCKS BY IMPACT AND EXPLOSION

The article analyzes the known criteria of brittle and ductile fracturing of rocks and model materials. It is shown that for the evaluation of fracture fragility under the impact and explosion the best preferred criteria are proposed by Cherepanov G.P. and Balankin A.S. Based on these criteria, the vast majority of rocks collapse as brittle materials to form dissipative structures (D S ), including the DS in the form of equally distributed local microcracks in the volume of rock except for a narrow class of argillaceous rocks and some varieties of coal, in which DS is being created mainly in the form of plastic deformation zone. The formation of dissipative structures in the form of local micro and macrocracks under the explosion and impact in monolithic rocks has the wave nature.

Kinetics of a bimolecular chemical reaction in the liquid phase with association of both reactants

Mathematical modeling of a bimolecular chemical reaction in the liquid phase was carried out taking account of association of both reactants. The formally simple chemical reaction is thus transformed into a multistage process, which results in the formation of temporal dissipative structures. It was found that, apart from the usual dynamic modes, there appear oscillations of the concentrations of intermediates, characterized by two considerably differing periods.

Autonomous Oscillations and Pattern Formation with Zero External Resistance during Silicon Electrodissolution

We report the existence of small autonomous amplitude oscillations without the presence of an external series resistor during electrodissolution of both p- and highly illuminated n-type Si electrodes in a 60 mM NH4F electrolyte at pH 1. This finding enabled us to study possible emergence of patterns without the presence of the global coupling induced by an external resistance. While with p-type electrodes we could not find a spatial bifurcation upon varying the parameters, stable domain-type patterns with distinct dynamics formed spontaneously when lowering the illumination intensity. Their emergence could be linked to the lateral coupling through valence band holes. Experiments where only part of the electrode was illuminated gave further insight into the role of the hole dynamics for the formation of spatio-temporal dissipative structures.

Complex Method of Detection Reliable Precursors of Stressed Rock Samples Failure

Studies of brittle rock samples failure were carried out in Laboratory of Geodynamics of Far-Eastern University, Vladivostok, Russia. It was assisted by servocontrol loading machine MTS-816, acoustic emission (AE) complex, and multi-channel complex. The regularities of formation and development of dissipative mesocracks structures in rock samples under uniaxial compression were determined as a result of complex deformation and acoustic experiments at final stage of loading. Anomalous deformations of high stressed rock samples were associated with acoustic characteristics. The system of reliable precursors of failure involving long-term and middle-term was established. This system of precursors reflects the stages of formation and development of dissipative mesodefects structures in high stressed rock samples.

Existence regimes for the formation of nonlinear dissipative structures in inhomogeneous magnetoplasmas with non-Maxwellian electrons

Nonlinear dissipative structures are studied in one and two dimensions in nonuniform magnetized plasmas with non-Maxwellian electrons. The dissipation is incorporated in the system through ion-neutral collisions. Employing the drift approximation, nonlinear drift waves are derived in 1D, whereas coupled drift-ion acoustic waves are derived in 2D in the weak nonlinearity limit. It is found that the ratio of the diamagnetic drift velocity to the velocity of nonlinear structure determines the nature (compressive or rarefactive) of the shock structure. The upper and lower bounds for velocity of the nonlinear shock structures are also found. It is noticed that the existence regimes for the drift shock waves in one and two dimensions for Cairns distributed electrons are very distinct from those with kappa distributed electrons. Interestingly, it is found that both compressive and rarefactive shock structures could be obtained for the one dimensional drift waves with kappa distributed electrons.

Dissipative Structures and Fractal Approach to the Formation of Non-Crystalline States

Found that the formation of fractal dissipative structures in non-crystalline solids associated with the creation of self-consistent fields of soft atomic configurations and thermal behavior of such structure-sensitive characteristics that meet the minimum energy dissipation for a given external parameters - speed cooling and process modes receipt. It is shown that this fact makes it possible to determine the non-crystalline structure through the processes of self-organization.

Описание процессов трибосистем и разработка износостойких материалов с использованием неравновесной термодинамики и теории самоорганизации

The work is devoted to the practical application of non-equilibrium thermodynamics and the theory of self-organization in tribology to obtain certain results, especially in the development of new wear-resistant materials. Wear rate decreases with decreasing entropy production. To reduce wear rate it is necessary to initiate and intensify the process of negative entropy production. Such processes are stable after the self-organization and formation of dissipative structures. The possibilities of shifting self-organization to the softer friction conditions are considered. Article gives examples of practical application of these provisions in order to reduce the wear rate. Such processes include the appropriate selection of the composition of the friction bodies, which can increase the probability of self-organization process.

The formation of dissipative structures in polymers as a model of synergy

Synergetic is an interdisciplinary area and describes the emergence of various kinds of structures, using the representation of the natural sciences. In this paper we studied the conditions for the appearance of thermodynamically stable amorphous-crystalline supramolecular structures on the basis of practical importance for the production of heat-resistant high-strength polymer fibers semi-rigid systems. It is found that in the process of structure formation in the coagulation of the polymer from solutions having supramolecular structures area a definite geometric shape and dimensions. Pattern formation in such systems can simulate the processes studied synergy. This is occurring in the process of self-organization of dissipative structures, transitions from one structure to another. This most discussed matter of self-organization on the “optical” scale level, are observed spherulites have a “correct” form and certain geometric dimensions comparable to the wavelength of visible light. Previously, this polymer does not crystallize at all considered. It is shown that for the study of supramolecular structures are the most convenient and informative experimental approaches are polarization-optical methods, which are directly “tuned” to the optical anisotropy of the structure and morphology. The great advantage of these methods is also possible to study the kinetics of structure formation processes without interfering the system under study.