This paper establishes a non-equilibrium thermodynamic constitutive model that can predict the undrained shear behavior of saturated sand. Starting from the basic laws of thermodynamics, the model does not require the classical concepts in elasto-plastic models, such as the yield function, the flow rule, and the hardening rule. It is also different from the existing thermodynamic constitutive models in soil mechanics literatures. The model does not use a complex nonlinear elastic potential as usually and introduces a coupling energy dissipative mechanism between the viscosity and elasticity relaxation, which is essential in granular materials. Then this model was used to simulate the undrained shear test of Toyoura sand. The model can predict the critical state, dilatancy-contraction and hardening-softening characteristics of sand during undrained triaxial shearing.
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http://dx.doi.org/10.3390/e21020136 | DOI Listing |
mSystems
January 2025
Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA.
Gluconeogenesis, the reciprocal pathway of glycolysis, is an energy-consuming process that generates glycolytic intermediates from non-carbohydrate sources. In this study, we demonstrate that robust and efficient gluconeogenesis in bacteria relies on the allosteric inactivation of pyruvate kinase, the enzyme responsible for the irreversible final step of glycolysis. Using the model bacterium as an example, we discovered that pyruvate kinase activity is inhibited during gluconeogenesis via its extra C-terminal domain (ECTD), which is essential for autoinhibition and metabolic regulation.
View Article and Find Full Text PDFLangmuir
January 2025
Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
Surface-active agents (surfactants) release potential energy as they migrate from one of two adjacent fluids onto their fluid-fluid interface, a process that profoundly impacts the system's energy and entropy householding. The continuum thermodynamics underlying such a surfactant-enriched binary-fluid system has not yet been explored comprehensively. In this article, we present a mathematical description of such a system, in terms of balance laws, equations of state, and permissible constitutive relations and interface conditions, that satisfies the first and second law of thermodynamics.
View Article and Find Full Text PDFJ Plant Physiol
January 2025
Federal Scientific Centre of the East Asia Terrestrial Biodiversity of the Far East Branch of the Russian Academy of Sciences, Vladivostok, 690022, Russia.
Calcium-dependent protein kinases (CDPKs) are very effective calcium signal decoders due to their unique structure, which mediates substrate-specific [Ca] signalling through phosphorylation. However, Ca-dependence makes it challenging to study CDPKs. This work focused on the effects of the overexpression of native and modified forms of the AtCPK1 gene on the tolerance of tobacco plants to heat and cold.
View Article and Find Full Text PDFMol Ecol
February 2025
Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture (CAS), Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.
Phenotypic plasticity plays an essential role in adaptive evolution. However, the molecular mechanisms of how genotype-by-environment interaction (G × E) effects shape phenotypic plasticity in marine organisms remain poorly understood. The crucial temperature-responsive trait triacylglycerol (TAG) content and its major gene adipose triglyceride lipase (Atgl) expression have divergent plastic patterns in two congeneric oyster species (Crassostrea gigas and Crassostrea angulata) to adapt to relative-cold/northern and relative-warm/southern habitats, respectively.
View Article and Find Full Text PDFAdv Model Simul Eng Sci
December 2024
CentraleSupélec, ENS Paris-Saclay, CNRS, LMPS-Laboratoire de Mécanique Paris-Saclay, Université Paris-Saclay, 4 Avenue des Sciences, 91190 Gif-sur-Yvette, France.
Prior to any numerical development, the paper objective is to answer first to a fundamental question: what is the mathematical form of the most general data-driven constitutive model for stable materials, taking maximum account of knowledge from physics and materials science? Here we restrict ourselves to elasto-(visco-)plastic materials under the small displacement assumption. The experimental data consists of full-field measurements from a family of tested mechanical structures. In this framework, a general data-driven approach is proposed to learn the constitutive model (in terms of thermodynamic potentials) from data.
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