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

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.

Biology and Demography of Creative Potential

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

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.

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

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.

Entropy change of open thermodynamic systems in self-organizing processes

The thermodynamic models available in the literature predict that during self-organizing processes the entropy of a cell considered as an open thermodynamic system decreases. This prediction leads to conclusion that cell imports a certain amount of negative entropy and generates entropy during irreversible metabolic processes. The controversial concept of negentropy was criticized recently. In this research a new model was proposed that isn?t based on the steady state approximation and describes living systems more realistically. The analysis of the suggested model of an open thermodynamic system far from equilibrium, led to the conclusion that the entropy during self-organizing processes increases during growth (of a molecule or a cell). Using as models the synthesis of an oligopeptide and a growing hydrocarbon chain, it was shown that entropy of an open thermodynamic system increases during addition of monomers (a self-organizing process). A derived equation confirms the results obtained by calculations with literature experimental values of molar entropy. The decrease of entropy observed in self-organizing processes occurred only during phase transition.

The Sgen Rate Maximization Postulate: Applications to Process-Path Analysis for Solidification and Micropyretic Synthesis

The principle of maximum entropy generation rate principle is reviewed for its applicability in Materials Science. The principle of MEPR states that, if there are sufficient degrees of freedom within a system, it will adopt a stable state at whichthe entropy generation (production) rateis maximized. Where feasible, the system will also try and adopt a steady state. MEPR determines the most probable state. MEPR thus allows for pathway selections that can occur in an open thermodynamic system. Recent work also shows that isolated systems and closed thermodynamic systems also display this principle. The Belousov-Zhabitonsky reaction is also described in the Sgen context. Both solidification morphologies and micropyretic process generated morphologies are studied as examples of the Sgen and MEPR.