Thermodynamic irreversibility

Abstract

Concepts of "reversible" and "irreversible" start out seeming simple enough, but students often become confused. This article tackles areas of confusion in hopes of providing clarity.

Molten Salt-Promoted MgO Adsorbents for CO2 Capture: Transient Kinetic Studies

“…29 Table S4 (Supporting Information) summarizes the standard thermodynamic data of MgO, CO 2 , and MgCO 3 formation. 30 Based on these data, thermodynamic calculations show the feasibility of a solid-state carbonization of MgO under a CO 2 gas atmosphere, according to the Gibbs free energy function described below. 31…”

“…When Δ G < 0, a spontaneous process occurs, when Δ G = 0, a reversible equilibrium process takes place, and when Δ G > 0, the chemical reaction is impossible Table S4 (Supporting Information) summarizes the standard thermodynamic data of MgO, CO 2 , and MgCO 3 formation . Based on these data, thermodynamic calculations show the feasibility of a solid-state carbonization of MgO under a CO 2 gas atmosphere, according to the Gibbs free energy function described below. , where Δ f H m θ (298 K) is the standard molar enthalpy of formation (kJ mol –1 ), S m θ (298 K) is the standard molar entropy of formation (J K –1 mol –1 ), Δ r H m θ is the standard molar enthalpy of reaction (kJ mol –1 ), Δ r S m θ is the standard molar entropy of reaction (J K –1 mol –1 ), and Δ r G m θ is the Gibbs free energy of reaction (kJ mol –1 ).…”

Macrophysiologic Roles of a Delivery System for Vulnerary Factors Needed for Bone Regeneration

“…In these preclinical osseous studies, either recombinant human BMP‐2 or 7 regenerated ablative wounds that ordinarily would not have healed by new bone formation. (These wounds were critical‐sized defects 39–40 …”

“…The reoccurring theme in preclinical BMP studies is the importance of the delivery system. A clinically relevant delivery system for BMP must have specific physical and chemical properties to localize BMP, to ensure interaction with mesenchymal pluripotential cells, and to provide instructional guidance for bone contour renewal 33–41 . Several additional properties will be introduced in the ensuing section.…”

Understanding Entropy Using Fundamental Stability Conditions

“…These are intuitive and empirical, but classically are treated as consequences of the second law (11,12). They are at the root of a recent focus on the "driving forces" of irreversibility (13)(14)(15)(16). One of these stability conditions involves temperature gradients across a system boundary.…”