scholarly journals Theory of Nerve Excitation in Reference to Energy Dissipation: An Example of Far from Equilibrium System

1974 ◽  
Vol 52 (4) ◽  
pp. 1094-1104 ◽  
Author(s):  
Y. Aizawa ◽  
Y. Kobatake
Keyword(s):  
Energy Dissipation ◽  
Equilibrium System ◽  
Far From Equilibrium ◽  
Nerve Excitation

Phase Equilibria under Irradiation

1993 ◽  
Vol 311 ◽  
Author(s):  
P. Bellonw ◽  
F. Soisson ◽  
Y. Grandjean ◽  
G. Martin
Keyword(s):  
Phase Equilibria ◽  
Phase State ◽  
Equilibrium Phase ◽  
Atomic Diffusion ◽  
Equilibrium System ◽  
Stationary Probability Distribution ◽  
Average Composition ◽  
Two Phase ◽  
Thermally Activated ◽  
Far From Equilibrium

ABSTRACTA solid under irradiation is a far-from equilibrium system, and therefore phase equilibria in such a system cannot be assessed from equilibrium thermodynamics. Starting from a kinetic description which incorporates the various processes responsible for atomic diffusion (e.g. thermally activated jumps, replacement sequences or displacement cascades), the various possible steady-states can be identified analytically or numerically, as well as their kinetic evolution on varying the control parameters of the system (e.g. temperature, average composition, irradiation flux, cascade density …). Furthermore, from stochastic versions of the kinetic model, potentials governing the stationary probability distribution of states can be derived, allowing to build dynamical equilibrium phase diagrams.Illustrating the above approach on the A2-B2 order-disorder transition, we have identified irradiation-induced two-phase state, cascade size and density effects on phase stability. By incorporating point defects, such description is well suited to study irradiation-induced segregation at sinks in concentrated alloys.

scholarly journals Natural self-interest, interactive representation, and the emergence of objects and Umwelt: An outline of basic semiotic concepts for biosemiotics

2003 ◽  
Vol 31 (2) ◽  
pp. 547-587
Author(s):  
Tommi Vehkavaara
Keyword(s):  
Point Of View ◽  
Living Systems ◽  
Natural Phenomena ◽  
Equilibrium System ◽  
Utility Concept ◽  
Self Interest ◽  
Concept Of Function ◽  
Far From Equilibrium ◽  
The One ◽  
Representative System

In biosemiotics, life and living phenomena are described by means of originally anthropomorphic semiotic concepts. This can be justified if we can show that living systems as self-maintaining far from equilibrium systems create and update some kind of representation about the conditions of their self-maintenance. The point of view is the one of semiotic realism where signs and representations are considered as real and objective natural phenomena without any reference to the specifically human interpreter. It is argued that the most basic concept of representation must be forward looking and that both C. Peirce’s and J. v. Uexküll’s concepts of sign assume an unnecessarily complex semiotic agent. The simplest representative systems do not have phenomenal objects or Umwelten at all. Instead, the minimal concept of representation and the source of normativity that is needed in its interpretation can be based on M. Bickhard’s interactivism. The initial normativity or natural self-interest is based on the ‘utility-concept’ of function: anything that contributes to the maintenance of a far from equilibrium system is functional to that system — every self-maintaining far from equilibrium system has a minimal natural self-interest to serve that function, it is its existential precondition. Minimal interactive representation emerges when such systems become able to switch appropriately between two or more means of maintaining themselves. At the level of such representations, a potentiality to detect an error may develop although no objects of representation for the system are provided. Phenomenal objects emerge in systems that are more complex. If a system creates a set of ongoingly updated ’situation images’ and can detect temporal invariances in the updating process, these invariances constitute objects for the system itself. Within them, a representative system gets an Umwelt and becomes capable of experiencing triadic signs. The relation between representation and its object is either iconic or indexical at this level. Correspondingly as in Peirce’s semeiotic, symbolic signs appear as more developed — for the symbolic signs, a more complex system is needed.

scholarly journals Far from Equilibrium Maximal Principle Leading to Matter Self-Organization

2009 ◽  
Vol 5 (3) ◽  
pp. 753-783
Author(s):  
Piero Chiarelli
Keyword(s):  
Free Energy ◽  
Energy Dissipation ◽  
Entropy Production ◽  
Chemical Reactions ◽  
Space Velocity ◽  
Maximum Energy ◽  
Self Organization ◽  
Minimum Entropy ◽  
Minimum Entropy Production ◽  
Far From Equilibrium

In this work an extremal principle driving the far from equilibrium evolution of a system of structureless particles is derived by using the stochastic quantum hydrodynamic analogy. For a classical phase (i.e., the quantum correlations decay on a distance smaller than the mean inter-molecular distance) the far from equilibrium kinetic equation can be cast in the form of a Fokker-Plank equation whose phase space velocity vector maximizes the dissipation of the energy-type function, named here, stochastic free energy.Near equilibrium the maximum stochastic free energy dissipation (SFED) is shown to be compatible with the Prigogine’s principle of minimum entropy production. Moreover, in quasi-isothermal far from equilibrium states, the theory shows that, in the case of elastic molecular collisions and in absence of chemical reactions, the maximum SFED reduces to the maximum free energy dissipation.When chemical reactions or relevant thermal gradients are present, the theory highlights that the Sawada enunciation of maximum free energy dissipation can be violated.The proposed model depicts the Prigogine’s principle of minimum entropy production near-equilibrium and the far from equilibrium Sawada’s principle of maximum energy dissipation as two complementary principia of a unique theory where the latter one is a particular case of the more general one of maximum stochastic free energy dissipation.Following the tendency to reach the highest rate of SFED, a system relaxing to equilibrium goes through states with higher order so that the matter self-organization becomes possible.

scholarly journals Using a system’s equilibrium behavior to reduce its energy dissipation in nonequilibrium processes

2019 ◽  
Vol 116 (13) ◽  
pp. 5920-5924 ◽  
Author(s):  
Sara Tafoya ◽  
Steven J. Large ◽  
Shixin Liu ◽  
Carlos Bustamante ◽  
David A. Sivak
Keyword(s):  
Friction Coefficient ◽  
Energy Dissipation ◽  
Molecular Machines ◽  
External Control ◽  
Energetic Efficiency ◽  
Square Root ◽  
Nonequilibrium Processes ◽  
Dna Hairpins ◽  
Equilibrium Behavior ◽  
Far From Equilibrium

Cells must operate far from equilibrium, utilizing and dissipating energy continuously to maintain their organization and to avoid stasis and death. However, they must also avoid unnecessary waste of energy. Recent studies have revealed that molecular machines are extremely efficient thermodynamically compared with their macroscopic counterparts. However, the principles governing the efficient out-of-equilibrium operation of molecular machines remain a mystery. A theoretical framework has been recently formulated in which a generalized friction coefficient quantifies the energetic efficiency in nonequilibrium processes. Moreover, it posits that, to minimize energy dissipation, external control should drive the system along the reaction coordinate with a speed inversely proportional to the square root of that friction coefficient. Here, we demonstrate the utility of this theory for designing and understanding energetically efficient nonequilibrium processes through the unfolding and folding of single DNA hairpins.

scholarly journals Using a System’s Equilibrium Behavior to Reduce Its Energy Dissipation in Non-Equilibrium Processes

2018 ◽  
Author(s):  
Sara Tafoya ◽  
Steven J. Large ◽  
Shixin Liu ◽  
Carlos Bustamante ◽  
David A. Sivak
Keyword(s):  
Friction Coefficient ◽  
Energy Dissipation ◽  
Optical Tweezers ◽  
Molecular Machines ◽  
External Control ◽  
Energetic Efficiency ◽  
Dna Hairpin ◽  
Equilibrium Processes ◽  
Far From Equilibrium ◽  
Non Equilibrium

Cells must operate far from equilibrium1, utilizing and dissipating energy continuously to maintain their organization and to avoid stasis and death. However, they must also avoid unnecessary waste of energy2. Recent studies have revealed that molecular machines are extremely efficient thermodynamically when compared to their macroscopic counterparts3,4. There are also tantalizing hints of molecular machines conserving energy while operating out of equilibrium5,6. However, the principles governing the efficient out-of-equilibrium operation of molecular machines remain a mystery. A theoretical framework has been recently formulated in which a generalized friction coefficient quantifies the energetic efficiency in non-equilibrium processes7,8. Moreover, it posits that to minimize energy dissipation, external control should drive the system along the reaction coordinate with a speed inversely proportional to the square root of that friction coefficient. Here, we test and validate the predictions of this theory by probing the non-equilibrium energetic efficiency of a single DNA hairpin subjected to unfolding and refolding protocols using a dual-trap optical tweezers.

KINEMATIC FEATURES OF THE LAPPING PROCESS AND DETERMINATION OF ITS BASIC PARAMETERS

2020 ◽  
Vol 7 (3) ◽  
pp. 23-28
Author(s):  
EZIZ SARVAN SHIRVAN ◽  
Keyword(s):  
Dynamic Properties ◽  
Cutting Speed ◽  
Equilibrium System ◽  
Technological Parameters ◽  
Kinematic Characteristics ◽  
Angular Velocities ◽  
Basic Parameters ◽  
Grinding Tool ◽  
Mathematical Relationships ◽  
Analytical Expressions

This paper discusses the kinematic characteristics of lapping process and the main parameters of the process. It was determined that the influencing degree of technological parameters to the forming surface and processes. It was projected the construction of the lapping head for processing of internal cylindrical surfaces, scheme of the lapping operation and graphic description of the forces influencing. The relationships between the axial, radial and tangential cutting forces and the effect of the combined force thereof are determined in order to ensure the necessary surface pressure. During the analysis geometric and mathematical relationships were obtained. The extracted analytical expressions can be realized by further experimental researches and can be used in engineering calculations of technological parameters of processing by lapping. Angular velocity, friction force, linear velocity, also the length of the tactile curve and the radius of the part can be considered the main kinematic and dynamic parameters of the process that the formation of the surface, also the course of the process depends on these parameters. Depending on the kinematic parameters, the wear nature of the tool changes and this changes the linear and angular velocities, which have a significant impact on the accuracy, quality and productivity of processing. When examining the technological capabilities of the process, the nature of the movement between the part and the grinding tool, also changes in cutting speed are often considered as a main factor. Analytical expressions were obtained to determine the main parameters of the process, taking into account the kinematic characteristics of the friction process. These expressions can be used in engineering calculations and allow to determine the optimal values of the processing mode. In order to obtain the required micrometric surface cleanliness and measurement accuracy, correlation relationships were established between the main parameters of the process, equations of the equilibrium system of shear forces were compiled and analytical expressions were obtained based on the analysis of kinematic and dynamic properties of the system.

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