The Living Cell as an Open Thermodynamic System: Bacteria and Irreversible Thermodynamics

1971 ◽  
Author(s):  
W. B. Mercer
Keyword(s):  
Living Cell ◽  
Thermodynamic System ◽  
Irreversible Thermodynamics ◽  
Open Thermodynamic System

Wellenausbreitung in einem offenen thermodynamischen System zeitlich veränderlicher Gesamtenergie / Wave Propagation in an open Thermodynamic System with Time Variation of the Total Energy

1970 ◽  
Vol 25 (5) ◽  
pp. 730-735
Author(s):  
H.-D. Freund ◽  
G. Locke
Keyword(s):  
Total Energy ◽  
Thermodynamic System ◽  
Acoustic Velocity ◽  
Wave System ◽  
Carrier System ◽  
Phase Step ◽  
Wave Characteristics ◽  
Time Averages ◽  
Absorption And Dispersion ◽  
Open Thermodynamic System

The absorption and dispersion of sound due to dissipative phenomena such as diffusion, heat conduction and viscous flow have been investigated by Herzfeld, Litovitz and others. Whereas in these studies the total energy of the carrier system remains constant, we consider the case that it is changing. It turnes out that the wavelength X remains constant, while all other wave characteristics become time depend and can be connected with the usual sound velocity of the carrier system ..The change in energy density takes place via the potential energy. Thus the original balance between potential and kinetic energy is disturbed. Modulation vibrations of the wave amplitudes around the time averages arise. In addition dephasing of the pressure and density components with respect to the acoustic velocity takes place. The phasevelocities are disturbed too. They differ from time dependence of c(t).These differences are running asymptotically towards zero, i. e. after a longer period of time a phase step remains of the total wave system. This phase step is negative for increasing energy of the carrier system and positive for decreasing energy. The value of the phase step is proportional to the wavelength λ, i. e. systems of this kind show dispersion.

scholarly journals Investigation of the dissipative structures following microseismic diffusion during hydraulic fracturing of methane-hydrate-bearing sand

2021 ◽  
Vol 230 ◽  
pp. 01015
Author(s):  
Victor Nazimko ◽  
Olga Pidgurna ◽  
Olexiy Kusen
Keyword(s):  
Hydraulic Fracturing ◽  
Methane Hydrate ◽  
Thermodynamic System ◽  
Dissipative Structures ◽  
Explicit Calculation ◽  
Structure Evolution ◽  
Liquid Injection ◽  
New Findings ◽  
Hydrate Deposit ◽  
Open Thermodynamic System

Hydraulic fracturing is a prospective technology for methane hydrate deposit exploitation. The evolution of hydraulically stimulated fractures around the point of liquid injection is simulated. For this purpose, the FLAC3D computer model is used because of its explicit calculation cycle that imitates real physics, prevents numerical instability, and reproduces a realistic path during simulation of the nonlinear rock massif behavior. The results of the simulation provide for new findings, namely, the spatial asymmetry and synchronism violation, spatial deviation, discontinuity, and recurrence during microseismic diffusion, which follow the process of hydraulic fracturing. In addition, dissipative structures were developed due to entropy production, since gas hydrate strata are an open thermodynamic system, which transforms and dissipates the energy of the injected liquid. The process of dissipative structure evolution should be controlled to enhance the gas yield from the hydrates.

Analysis to Stress Relaxation Phenomena of Viscoelastic Materials by Means of Irreversible Thermodynamics (Ⅰ)

2005 ◽  
Vol 297-300 ◽  
pp. 365-370
Author(s):  
Guang Ze Dai ◽  
Lanying Yu ◽  
Jian Ke ◽  
Qing Qing Ni
Keyword(s):  
Stress Relaxation ◽  
Viscoelastic Medium ◽  
Stable Equilibrium ◽  
Uniaxial Stress ◽  
Thermodynamic System ◽  
Irreversible Thermodynamics ◽  
Stable Equilibrium State ◽  
Viscoelastic Solid ◽  
Solid Materials ◽  
Generalized Coordinates

Through defining a piece of viscoelastic medium as a thermodynamic system described by the generalized coordinates in the stress relaxation process, the evolution equation is derived by making use of the 1st law of thermodynamics, the 2nd law of thermodynamics and the Onsager’s principle. Based on the general solutions of the evolution, the constitutive expressions of uniaxial stress relaxation are obtained for both ideal viscoelastic solid materials and ideal viscoelastic fluid one respectively, in terms of the situation whether the coordinates participating in the entropy production are in stable or neutrally stable equilibrium state. As the result, whether the stress relaxes to a constant or zero depends on whether the free energy in viscoelastic medium is left or not.

Application of Irreversible Thermodynamics to Diffusion in Solids with Internal Surfaces

2020 ◽  
Vol 45 (4) ◽  
pp. 401-417
Author(s):  
Anna G. Knyazeva
Keyword(s):  
Thermodynamic Description ◽  
Stress Gradient ◽  
Thermodynamic System ◽  
Irreversible Thermodynamics ◽  
State Variables ◽  
Transfer Coefficients ◽  
State Equations ◽  
Diffusion In Solids ◽  
Internal Surfaces ◽  
Mass Transfer Mechanism

AbstractTwo types of additional variables were included in the set of state variables and were used for a thermodynamic description of diffusion in an ordinary thermodynamic system. Vacancies are included in the mass balance. Internal surfaces are massless but are characterized by some energy, which is included in the energy balance of the thermodynamic system. Fluxes of components, vacancies, and surfaces were expressed via two groups of thermodynamic constitutive equations of with cross effects. The first group follows from the Gibbs equation. These are state equations in a differential form. The second group relates generalized thermodynamic fluxes to generalized thermodynamic forces. It was shown for a binary system that only three of six transfer coefficients are independent even if the mass transfer mechanism caused by the stress gradient is taken into account.

scholarly journals Assessment of open thermodynamic system concepts for fluviokarst temperature calculations – an example, the Cent-Fonts resurgence (Hérault, France)

2014 ◽  
Vol 11 (1) ◽  
pp. 169-198 ◽  
Author(s):  
P. Machetel ◽  
D. A. Yuen
Keyword(s):  
Extreme Values ◽  
Reynolds Numbers ◽  
Thermodynamic System ◽  
Implicit Methods ◽  
Dimensionless Numbers ◽  
Adiabatic Wall ◽  
Conservative Tracer ◽  
Relative Errors ◽  
The One ◽  
Open Thermodynamic System

Abstract. We propose to assess the error done when temperature is considered as a conservative tracer in fluviokarst studies. As a matter of fact, heat exchanges occur between karstic Conduit System (CS) and Porous Fractured Matrix (PFM) that prevents from using this approximation without caution. The conservative tracer approximation boils down to consider the cooling of CS water by PFM flow in an open thermodynamic system where the CS is bounded by an Adiabatic Wall (AW). The resulting CS water temperature contrasts with the one obtained from more complete models (CW), which also take into account heat conduction within the CS, within the PFM, and from the CS to PFM through CS a Conductive Wall. In order to assess first orders of this error, the dimensionless equations, characteristic of CS cooling by PFM, have been solved thanks to Alternate Finite Difference Implicit methods both in AW and CW configurations. Four groups of dimensionless numbers appear in the various terms of energy and mass equations among which the Peclet and Reynolds numbers depict the large morphologic and hydrologic variability of natural karstic systems. A parametric exploration of the differences between AW and CW models has then been conducted vs. Peclet numbers (Pe numbers varying from 106 to 109, at constant CS Reynolds number) and vs. Reynolds numbers (Red varying from 103 to 107, at constant Peclet number). The error curves bound finite volumes in the Peclet–Reynolds space that converge uniformly to zero for the extreme values of these parameters. However, for Peclet and Reynolds numbers characteristic of realistic fluviokarst configurations, the errors reach finite values, that give first order information assessing the error done by considering temperatures as conservative tracers. Maximum relative errors around 10−2 (in fact 0.0092) have been found varying Pe; while it remained slightly lower than 0.7 × 10−2 varying Red. An illustrative example of the temperature conservative tracer AW approximation is presented with the data obtained from the main morphologic and hydrologic properties of the Cent–Font resurgence (Hérault, France). According to the results, the error reached at the output of the fluviokarst is 0.00613 (for Pe = 1.4993 × 108 and Red = 4.2969 × 104). When rescaled to the physical domain, this error leads to a temperature difference of 1.77 K between the CW and AW configurations.

scholarly journals Biology and Demography of Creative Potential

2019 ◽  
Author(s):  
Alexander Kholmanskiy
Keyword(s):  
Homo Sapiens ◽  
Kinetic Equations ◽  
Thermodynamic System ◽  
Logistic Equation ◽  
Historical Time ◽  
Creative Potential ◽  
System Equilibrium ◽  
Global Problems ◽  
North And South ◽  
Open Thermodynamic System

The creative potential of homo sapiens is the biological basis of his spirituality. To take into account factor of spirituality in analysis of global problems of demography and ecology used analogies of chemical kinetics. Stable in the historical time, population of people was modeled by open thermodynamic system, equilibrium state of which depends on climate and geophysics. The demography of creative potential was divided into two geographical zones - north and south. Process of society sapientation was formalized by introducing into logistic equation of Verhulst, in addition to a couple of parents, at least one more teacher from among educated people. Stationary solution of the modified kinetic equations determines optimal demography for sustainable development of population in accordance with its education index. The solution of the demographic, energy and environmental problems of mankind is determined by the level of world creative potential, the growth of which is currently limited by the consumption paradigm.

Energy flow in organisms

2017 ◽  
Author(s):  
Andrew Clarke
Keyword(s):  
Energy Budget ◽  
Energy Flow ◽  
Chemical Potential ◽  
Thermodynamic System ◽  
Biophysical Model ◽  
Full Description ◽  
Relative Importance ◽  
Budget Model ◽  
Cool Environment ◽  
Open Thermodynamic System

An organism is an open thermodynamic system exchanging both energy and materials with its environment. Organisms exchange energy with their environment by radiation, conduction, convection and evaporation of water. The relative importance of these varies with the organism and its situation. Newton’s Law of Cooling is a simplification that is useful only for warm endotherms in a still, cool environment. For all other circumstances a full biophysical treatment is necessary. Flows of chemical potential energy can be captured by a balanced energy budget. A full description of the energy balance of an organism requires the coupling of a biophysical model of heat flow with an energy budget model. This combination provides a powerful tool for modelling the thermal and energetic niches of organisms, and to predict how these might change in the future.

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