Chemical Change in Deforming Materials

1993 ◽  
Author(s):  
Brian Bayly
Keyword(s):  
Stress State ◽  
Elementary Mathematics ◽  
Chemical Potential ◽  
Chemical Change ◽  
Technical Literature ◽  
Chemical Changes ◽  
Viscous Deformation ◽  
Macroscopic Level ◽  
Fundamental Understanding ◽  
Non Equilibrium

This book is the first to detail the chemical changes that occur in deforming materials subjected to unequal compressions. While thermodynamics provides, at the macroscopic level, an excellent means of understanding and predicting the behavior of materials in equilibrium and non-equilibrium states, much less is understood about nonhydrostatic stress and interdiffusion at the chemical level. Little is known, for example, about the chemistry of a state resulting from a cylinder of deforming material being more strongly compressed along its length than radially, a state of non-equilibrium that remains no matter how ideal the cylinder's condition in other respects. M. Brian Bayly here provides the outline of a comprehensive approach to gaining a simplified and unified understanding of such phenomena. The author's perspective differs from those commonly found in the technical literature in that he emphasizes two little-used equations that allow for a description and clarification of viscous deformation at the chemical level. Written at a level that will be accessible to many non-specialists, this book requires only a fundamental understanding of elementary mathematics, the nonhydrostatic stress state, and chemical potential. Geochemists, petrologists, structural geologists, and materials scientists will find Chemical Change in Deforming Materials interesting and useful.

scholarly journals Interplay of structural and dynamical heterogeneity in the nucleation mechanism in Ni

2021 ◽  
Author(s):  
Grisell Díaz Leines ◽  
Angelos Michaelides ◽  
Jutta Rogal
Keyword(s):  
High Performance ◽  
Nucleation Mechanism ◽  
Metal Alloys ◽  
Crystal Nucleation ◽  
Dynamical Heterogeneity ◽  
Fundamental Understanding ◽  
Equilibrium Process ◽  
Non Equilibrium

Gaining fundamental understanding of crystal nucleation processes in metal alloys is crucial for the development and design of high-performance materials with targeted properties. Yet, crystallizationis a complex non-equilibrium process and,...

scholarly journals The homogeneous catalysis of gaseous reactions by iodine. The decomposition of propionic aldehyde, and a general discussion

1933 ◽  
Vol 142 (846) ◽  
pp. 77-88 ◽  
Keyword(s):  
Kinetic Analysis ◽  
Homogeneous Catalysis ◽  
Chemical Change ◽  
Point Of View ◽  
The Other ◽  
Side Reactions ◽  
General Point ◽  
Chemical Changes ◽  
Secondary Reactions ◽  
The One

Previous papers have dealt with the homogeneous catalysis of the decomposition of ethers and of acetaldehyde by iodine. The problem of the mechanism of these catalysed reactions can be approached in two ways: on the one hand, by seeking to obtain as complete a picture as possible of the types of chemical change which are susceptible to the action of a given catalyst, and, the catalysts which will promote a given chemical change; and, on the other hand, by investigating in detail the kinetics and molecular statistics of individual reactions. Experiments on the different kinds of reaction which iodine will catalyse are being published elsewhere. Most of the chemical changes have involved too many side reactions, or secondary reactions with the catalyst, to be suitable for complete kinetic analysis. Nevertheless, they show the chemical specificity of the action of iodine in the clearest manner, and this aspect of the problem is discussed from a general point of view in the last section of the present paper.

Catalytic chemical potential shift on the surface of nonstoichiometric oxides under non-equilibrium gas atmosphere

2005 ◽  
Vol 176 (31-34) ◽  
pp. 2411-2416 ◽  
Author(s):  
Keiji Yashiro ◽  
Shigenori Onuma ◽  
Maya Sase ◽  
Atsushi Kaimai ◽  
Takanori Otake ◽  
...  
Keyword(s):  
Chemical Potential ◽  
Potential Shift ◽  
Gas Atmosphere ◽  
Nonstoichiometric Oxides ◽  
Non Equilibrium

scholarly journals Non-Equilibrium Thermodynamic Approach to Ca2+-Fluxes in Cancer

2020 ◽  
Vol 10 (19) ◽  
pp. 6737 ◽  
Author(s):  
Umberto Lucia ◽  
Giulia Grisolia
Keyword(s):  
Cell Membrane ◽  
Electric Potential ◽  
Chemical Potential ◽  
Waste Heat ◽  
Potential Gradient ◽  
Ion Fluxes ◽  
Biochemical Processes ◽  
Cancer And Inflammation ◽  
Ion Species ◽  
Non Equilibrium

Living systems waste heat in their environment. This is the measurable effect of the irreversibility of the biophysical and biochemical processes fundamental to their life. Non-equilibrium thermodynamics allows us to analyse the ion fluxes through the cell membrane, and to relate them to the membrane electric potential, in order to link this to the biochemical and biophysical behaviour of the living cells. This is particularly interesting in relation to cancer, because it could represent a new viewpoint, in order to develop new possible anticancer therapies, based on the thermoelectric behaviour of cancer itself. Here, we use a new approach, recently introduced in thermodynamics, in order to develop the analysis of the ion fluxes, and to point out consequences related to the membrane electric potential, from a thermodynamic viewpoint. We show how any increase in the cell temperature could generate a decrease in the membrane electric potential, with a direct relation between cancer and inflammation. Moreover, a thermal threshold, for the cell membrane electric potential gradient, has been obtained, and related to the mitotic activity. Finally, we obtained the external surface growth of the cancer results related (i) to the Ca2+-fluxes, (ii) to the temperature difference between the the system and its environment, and (iii) to the chemical potential of the ion species.

Weathering Indices Used in Evaluation of the Weathering State of Rock Material

2018 ◽  
pp. 132-186
Author(s):  
Sener Ceryan
Keyword(s):  
Stress State ◽  
Literature Review ◽  
Chemical Change ◽  
Engineering Properties ◽  
Rock Materials ◽  
Weathering Indices ◽  
Weathered Rocks ◽  
Points Of View ◽  
Definition Of ◽  
Time Form

There are various definition of weathering and differences between authors seem to steam in part from the different viewpoints of pedolog, geomorpholog, geolog, geochemists and geology engineer. In this study, weathering is handled from various aspects such as time, form and phases of progress, studies it is majored and research scale. The engineering behavior of rock materials depends not only on stress state and stress history but also on the physical, mineralogical and chemical change of the rock materials due to weathering. Weathering indices are used to define these changes due to weathering. Several weathering indices have been devised for quantifying the changes in the intrinsic properties of rocks from different points of view, some of which can be related to the engineering properties of weathered rocks. The most commonly used methods can be broadly categorized as chemical, mineralogical-petrographical, petro-chemical and engineering indices. In this study, the brief literature review for weathering indices used to evaluate of the effects for weathering of rock materials.

Tensorielle chemische Potentiale — eine notwendige Erweiterung der Gibbs'schen Thermodynamik / Tensorial Chemical Potentials — a Necessary Extension of Gibbs' Thermodynamics

1975 ◽  
Vol 30 (11) ◽  
pp. 1433-1440 ◽  
Author(s):  
B. Stuke
Keyword(s):  
Chemical Potential ◽  
Spherically Symmetric ◽  
Relaxation Phenomena ◽  
Pressure Tensor ◽  
Equilibrium Thermodynamics ◽  
Equilibrium Conditions ◽  
Chemical Potentials ◽  
Thermodynamic Pressure ◽  
Fundamental Equations ◽  
Non Equilibrium

In a system with a non spherically symmetric pressure tensor, the chemical potential of at least one substance in the system has to be a tensor of the same character as the pressure. The necessary generalization of Gibbs' fundamental equations of thermodynamics is presented. Being already of consequence for equilibrium, this extension is more important for non-equilibrium thermodynamics, in particular for the proper thermodynamic formulation of general relaxation phenomena. Reasons are given why the distinction between dynamic and thermodynamic pressure, originating from the incomplete formulation of customary thermodynamics, is erroneous. Finally a tensorial temperature is introduced which can exist under extreme non-equilibrium conditions, e.g. shock waves

Thermodynamics and foundations of mass-action kinetics

2005 ◽  
Vol 30 (1-2) ◽  
pp. 3-113 ◽  
Author(s):  
Miloslav Pekař
Keyword(s):  
Chemical Kinetics ◽  
Reaction Rate ◽  
Chemical Potential ◽  
Kinetic Equations ◽  
Reaction Rates ◽  
Equilibrium States ◽  
Mass Action ◽  
Rate Equations ◽  
Mass Action Kinetics ◽  
Non Equilibrium

A critical overview is given of phenomenological thermodynamic approaches to reaction rate equations of the type based on the law of mass-action. The review covers treatments based on classical equilibrium and irreversible (linear) thermodynamics, extended irreversible, rational and continuum thermodynamics. Special attention is devoted to affinity, the applications of activities in chemical kinetics and the importance of chemical potential. The review shows that chemical kinetics survives as the touchstone of these various thermody-namic theories. The traditional mass-action law is neither demonstrated nor proved and very often is only introduced post hoc into the framework of a particular thermodynamic theory, except for the case of rational thermodynamics. Most published “thermodynamic'’ kinetic equations are too complicated to find application in practical kinetics and have merely theoretical value. Solely rational thermodynamics can provide, in the specific case of a fluid reacting mixture, tractable rate equations which directly propose a possible reaction mechanism consistent with mass conservation and thermodynamics. It further shows that affinity alone cannot determine the reaction rate and should be supplemented by a quantity provisionally called constitutive affinity. Future research should focus on reaction rates in non-isotropic or non-homogeneous mixtures, the applicability of traditional (equilibrium) expressions relating chemical potential to activity in non-equilibrium states, and on using activities and activity coefficients determined under equilibrium in non-equilibrium states.

scholarly journals Differential thermopower images as a probe of many-body effects in quantum point contacts

2021 ◽  
Author(s):  
Yuan Ren ◽  
Joshua Folk ◽  
Yigal Meir ◽  
Tomaz Rejec ◽  
Werner Wegscheider
Keyword(s):  
Density Functional ◽  
Chemical Potential ◽  
Local Density ◽  
Equilibrium Density ◽  
Quantum Point Contacts ◽  
Point Contacts ◽  
Many Body ◽  
Quantum Point ◽  
Many Body Effects ◽  
Non Equilibrium

Abstract Mesoscopic circuit elements such as quantum dots and quantum point contacts (QPCs) offer a uniquely controllable platform for engineering complex quantum devices, whose tunability makes them ideal for generating and investigating interacting quantum systems. However, the conductance measurements commonly employed in mesoscopics experiments are poorly suited to discerning correlated phenomena from those of single-particle origin. Here, we introduce non-equilibrium thermopower measurements as a novel approach to probing the local density of states (LDOS), offering an energy-resolved readout of many-body effects. We combine differential thermopower measurements with non-equilibrium density functional theory (DFT) to both confirm the presence of a localized state at the saddle point of a QPC and reveal secondary states that emerge wherever the reservoir chemical potential intersects the gate-induced potential barrier. These experiments establish differential thermopower imaging as a robust and general approach to exploring quantum many-body effects in mesoscopic circuits.

scholarly journals SAMANYA SHODHANA OF RAW VANGA BY DHALANA METHOD WITH SPECIAL REFERENCE TO RASTARANGINI: PHARMACEUTICO-ANALYTICAL STUDY FROM ASHVIN RURAL AYURVED COLLEGE, MANCHIHILL, SANGAMNER, MAHARASHTRA

2020 ◽  
Vol 8 (7) ◽  
pp. 3886-3889
Author(s):  
Supriya A. Giri ◽  
Ravindra Atram ◽  
Smita Kolte ◽  
Sanjeev Lokhande
Keyword(s):  
Special Reference ◽  
Analytical Study ◽  
Chemical Change ◽  
Chemical Changes ◽  
Physical Chemical ◽  
Before And After ◽  
Physical Changes

Background: Shodhana is a process which separate mala by doing Peshana, Khalana, Mardana, Dhala-na, Nirvapana, Swedhana etc. Objective: To study the physical, chemical changes in raw Vanga before and after Samanya Shodhana. Materials & Methods: In the present study, Vanga Shodhana is carried out by Dhalana method in different media as Taila, Takra, Gomutra, Aranala, Kulattha Kwatha for 7 times. Results and Conclusions: Physical changes take place in metal useful for further process. Removal of zinc and lead from the raw Vanga shows the importance of Malavicchedana property of Shodhana. Vanga un-dergoes the oxidation as a chemical change which quickens the further process of Jarana and Marana

scholarly journals Organocatalytic Control over a Fuel-Driven Transient Esterification Network

2020 ◽  
Author(s):  
Michelle van der Helm ◽  
Chang-Lin Wang ◽  
Mariano Macchione ◽  
Eduardo Mendes ◽  
Rienk Eelkema
Keyword(s):  
Chemical Change ◽  
Polymer System ◽  
Reaction Networks ◽  
Polymer Conformation ◽  
Controlled Processes ◽  
Full Control ◽  
Ester Formation ◽  
Driven System ◽  
Ester Yield ◽  
Non Equilibrium

<p>Signal transduction in living systems is the conversion of information into a chemical change and the principal process by which cells communicate. This process enables phenomena such as time-keeping and signal amplification. In nature, these functions are encoded in non-equilibrium (bio)chemical reaction networks (CRNs) controlled by enzymes. While these catalytically controlled processes are an integral part of biocatalytic pathways, man-made analogs are rare. Here, we incorporate catalysis in an artificial fuel driven out-of-equilibrium CRN. The study entails the design of an organocatalytically controlled fuel driven esterification CRN, where the forward (ester formation) and backward reaction (ester hydrolysis) are controlled by varying the ratio of two different organocatalysts: pyridine and imidazole. This catalytic regulation enables full control over ester yield and lifetime. The fuel-driven strategy is subsequently used in the design of a responsive polymer system, where transient polymer conformation and aggregation can be controlled through variation of fuel and catalysts levels. Altogether, we show how organocatalysis is an important tool to exert control over a man-made fuel driven system and induce a change in a macromolecular superstructure, as ubiquitously found in natural non-equilibrium systems. </p>

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