Identical thermodynamical processes and entropy

2005 ◽  
Vol 83 (6) ◽  
pp. 629-636 ◽  
Author(s):  
Joaquim Anacleto

Starting from the concept of identical thermodynamical processes, we treat invariance under interchange of identical processes as a symmetry. We show the conservation of entropy in reversible processes to be intimately related to this symmetry. PACS Nos.: 44.60, 65.50

2019 ◽  
Vol 126 (2) ◽  
pp. 134
Author(s):  
И.В. Станишевский ◽  
Т.А. Павич ◽  
С.М. Арабей

AbstractThe europium(III)–tris(dibenzoylmethane)–triphenylphosphine oxide complex was studied in the polycrystalline state and in toluene at 298 K using the luminescence excitation method with two-stage rectangular pulses with decreasing intensity of stages. Experimental nonmonotonic kinetic curves were numerically simulated within the framework of a four-level dynamic model describing reversible processes in the complex, associated with its structural rearrangement. The maximum correspondence between the experimental and simulated curves was obtained using an iterative approximation performed using the Nelder–Mead algorithm. Based on the obtained numerical values of the rate constants and parameters of the model, experimental kinetics were interpreted, and it was concluded that they are a consequence of the processes associated with changes in the ligand composition of the Eu^3+ chelate.


Quantum ◽  
2020 ◽  
Vol 4 ◽  
pp. 231
Author(s):  
Paul Boes ◽  
Rodrigo Gallego ◽  
Nelly H. Y. Ng ◽  
Jens Eisert ◽  
Henrik Wilming

Fluctuation theorems impose constraints on possible work extraction probabilities in thermodynamical processes. These constraints are stronger than the usual second law, which is concerned only with average values. Here, we show that such constraints, expressed in the form of the Jarzysnki equality, can be by-passed if one allows for the use of catalysts---additional degrees of freedom that may become correlated with the system from which work is extracted, but whose reduced state remains unchanged so that they can be re-used. This violation can be achieved both for small systems but also for macroscopic many-body systems, and leads to positive work extraction per particle with finite probability from macroscopic states in equilibrium. In addition to studying such violations for a single system, we also discuss the scenario in which many parties use the same catalyst to induce local transitions. We show that there exist catalytic processes that lead to highly correlated work distributions, expected to have implications for stochastic and quantum thermodynamics.


1976 ◽  
Vol 8 (2) ◽  
pp. 416-432 ◽  
Author(s):  
F. P. Kelly

The behaviour in equilibrium of networks of queues is studied. Equilibrium distributions are obtained and in certain cases it is shown that the state of an individual queue is independent of the state of the rest of the network. The processes considered in this paper are irreversible; however, the method used to establish equilibrium distributions is one which has previously only been used when dealing with reversible processes. Results are obtained for models of communication networks, machine interference and birth-illness-death processes.


2000 ◽  
Author(s):  
George A. Adebiyi

Abstract A novel approach is proposed for combining the first and second laws of thermodynamics for systems undergoing arbitrary, non-reversible processes. A reference environment at an intensive state (p0, T0) is assumed, and combination of the two laws of thermodynamics yields the familiar equations used in the exergy analysis of processes. The application of the laws of thermodynamics was made first to non-flow processes involving closed systems. An extension to the control volume and flow processes was carried out via the use of the Reynolds transport theorem.


2005 ◽  
Vol 71 (2) ◽  
pp. 912-920 ◽  
Author(s):  
Benoît Gassilloud ◽  
Christophe Gantzer

ABSTRACT Viral inactivation and adhesion-aggregation in water are often studied as separate phenomena. When the focus is placed on viral adhesion-aggregation, inactivation is neglected because the phenomena under investigation occur over a short period measured in days. When viral inactivation is studied, adhesion-aggregation phenomena are considered to be negligible because viral survival is traced over several days or months. In the present work, we took a global approach, examining the relative contributions of each of these processes in a complex system composed of groundwater, Poliovirus 1, and a hydrophobic container (polypropylene) maintained in a dark environment at 20°C. We demonstrated that infectious viral load fell off 2.8 log10 during the first 20 days. During this time, adhesion was far from negligible because it accounted for most of the decline, 1.5 log10. Adhesion was undoubtedly favored by the presence of divalent ions in the groundwater. After 20 days, aggregation may also have been the cause of 0.66 to 0.92 log10 of viral loss. Finally, viral inactivation was quantitatively the lowest phenomena because it only explained 0.38 to 0.64 log10 of the viral loss. This study thus clearly demonstrated that estimates of viral survival in a given system must always take into account adhesion-aggregation phenomena which may be responsible for the majority of viral loss in the aqueous phase. Adhesion and aggregation are reversible processes which may lead to an underestimation of viral load in certain studies.


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