irreversible process
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Entropy ◽  
2022 ◽  
Vol 24 (1) ◽  
pp. 83
Author(s):  
Alexey Nikulov

The law of entropy increase postulates the existence of irreversible processes in physics: the total entropy of an isolated system can increase, but cannot decrease. The annihilation of an electric current in normal metal with the generation of Joule heat because of a non-zero resistance is a well-known example of an irreversible process. The persistent current, an undamped electric current observed in a superconductor, annihilates after the transition into the normal state. Therefore, this transition was considered as an irreversible thermodynamic process before 1933. However, if this transition is irreversible, then the Meissner effect discovered in 1933 is experimental evidence of a process reverse to the irreversible process. Belief in the law of entropy increase forced physicists to change their understanding of the superconducting transition, which is considered a phase transition after 1933. This change has resulted to the internal inconsistency of the conventional theory of superconductivity, which is created within the framework of reversible thermodynamics, but predicts Joule heating. The persistent current annihilates after the transition into the normal state with the generation of Joule heat and reappears during the return to the superconducting state according to this theory and contrary to the law of entropy increase. The success of the conventional theory of superconductivity forces us to consider the validity of belief in the law of entropy increase.


Entropy ◽  
2022 ◽  
Vol 24 (1) ◽  
pp. 76
Author(s):  
Karo Michaelian ◽  
Ramón Eduardo Cano Mateo

Through a modern derivation of Planck’s formula for the entropy of an arbitrary beam of photons, we derive a general expression for entropy production due to the irreversible process of the absorption of an arbitrary incident photon spectrum in material and its dissipation into an infrared-shifted grey-body emitted spectrum, with the rest being reflected or transmitted. Employing the framework of Classical Irreversible Thermodynamic theory, we define the generalized thermodynamic flow as the flow of photons from the incident beam into the material and the generalized thermodynamic force is, then, the entropy production divided by the photon flow, which is the entropy production per unit photon at a given wavelength. We compare the entropy production of different inorganic and organic materials (water, desert, leaves and forests) under sunlight and show that organic materials are the greater entropy-producing materials. Intriguingly, plant and phytoplankton pigments (including chlorophyll) reach peak absorption exactly where entropy production through photon dissipation is maximal for our solar spectrum 430<λ<550 nm, while photosynthetic efficiency is maximal between 600 and 700 nm. These results suggest that the evolution of pigments, plants and ecosystems has been towards optimizing entropy production, rather than photosynthesis. We propose using the wavelength dependence of global entropy production as a biosignature for discovering life on planets of other stars.


2021 ◽  
Vol 30 (6) ◽  
pp. 630-635
Author(s):  
Jamil Ahmad ◽  

The relationship between entropy and reversible heat and temperature is developed using a simple cycle, in which an ideal gas is subjected to isothermal expansion and compression and heated and cooled between states. The procedure is easily understood by students if they have knowledge of calculations involving internal energy, reversible work, and heat capacity for an ideal gas. This approach avoids the more time-consuming Carnot cycle. The treatment described here illustrates how the total entropy change resulting from an irreversible process is always positive.


Author(s):  
Karo Michaelian ◽  
Ramon Eduardo Cano Mateo

Through a modern derivation of Planck's formula for the entropy of an arbitrary beam of photons we derive a general expression for the entropy production due to the irreversible process of the absorption of an arbitrary incident photon spectrum in material and its dissipation into an infrared-shifted grey-body emitted spectrum, the rest being reflected or transmitted. Employing the framework of Classical Irreversible Thermodynamic theory, we define the generalized thermodynamic flow as the flow of photons from the incident beam into the material and the generalized thermodynamic force is then just the entropy production divided by the photon flow which is the entropy production per unit photon at a given wavelength. We compare the entropy production under sunlight of different inorganic and organic materials (water, desert, leaves and forests) and show that organic materials are the greater entropy producing materials. Intriguingly, plant and phytoplankton pigments (including chlorophyll) have peak absorption exactly where entropy production through photon dissipation is maximal for our solar spectrum $430&lt;\lambda&lt;550$ nm, while photosynthetic efficiency is maximal between 600 and 700 nm. These results suggest that the evolution of pigments, plants and ecosystems has been towards optimizing entropy production rather than photosynthesis. We propose using the wavelength dependence of global entropy production as a biosignature for discovering life on planets of other stars.


Author(s):  
Shuwana Tasleem

Abstract: Reactive distillation processes are very promising in substituting Sconventional liquid phase reaction processes. However this technology is not suitable for all kind of processes or types of reaction. Therefore, assessing the feasibility of these process concepts forms an important area in current and future research and development activities. The present paper focuses on the feasibility studies based on the construction of residue curve maps for the toluene methylation system. The RCMs were constructed and analyzed; it is concluded that the process of synthesis of xylenes when carried out in the reactive distillation column enhances the selectivity of the desired para isomer. Keywords: Reactive Distillation, Residue Curve Maps, Feasibility Study, Toluene Methylation, Aspen Plus


Author(s):  
Shuwana Tasleem

Abstract: In this study, a steady state simulation of the process for the production of xylene isomers by reactive distillation was performed using Aspen Plus software. The simulations were aimed studying the parameters like number of stages in the different sections of the RD column, reflux ratio, and the boil-up ratio, which maximize the conversion of Toluene and improves the selectivity and yield of the p- Xylene. Keywords: Reactive Distillation, Process Intensification, Toluene Methylation, Aspen Plus, Simulation Studies,


2021 ◽  
Author(s):  
Joonhyuk Choi ◽  
Shuhao Wang ◽  
Yang Li ◽  
Nan Hao ◽  
Brian M Zid

Aging is an irreversible process characterized by a progressive loss of homeostasis in cells, which often manifests as protein aggregates. Recently, it has been speculated that aggregates of RNA-binding proteins (RBPs) may go through pathological transitions during aging and drive the progression of age-associated neurodegenerative diseases. Using Saccharomyces cerevisiae as a model system of aging, we find that P-bodies - an RBP granule that is formed and can be beneficial for cell growth during stress conditions - naturally form during aging without any external stresses and an increase in P-body intensity is negatively correlated with the future lifespan of yeast cells. When mother cells transfer age-induced P-bodies to daughter cells, the mother cells extend lifespan, while the daughter cells grow poorly, suggesting that these age-induced P-bodies may be directly pathological. Furthermore, we find that suppressing acidification of the cytosol during aging slows down the increase in the intensity of P-body foci and extends lifespan. Our data suggest that acidification of the cytosol may facilitate the pathological transition of RBP granules during aging.


Author(s):  
I. V. Makarov ◽  
S. A. Krasnoshchekov

Summary. The article (didactic material) addresses the following aspects of the study of reversible regression in early childhood: question history, systematics, regression symptoms, including in childhood autism. The authors analyze the available data, express the opinion that the possibilities of reversible regression therapy in children have not been studied, there are no accurate data on the pathogenesis of these disorders, indicate the need to assess the dynamics of the condition, taking into account the age and sex factors of the child.The authors conclude that reversible regression is a pathological condition developing against a background of relatively favorable child development, in which there is a prolonged decay of previously acquired skills followed by partial or complete recovery. Unlike dementia, which is an irreversible process, regression has the stage of restoring lost functions. In studying the issue, clinical-dynamic analysis of variants of reversible regression of early childhood, an understanding of gender and age differences in the symptoms of the disorder, and prognosis criteria.


Author(s):  
Margaryta Bespalko ◽  
Tetiana Kochubey ◽  
Nataliia Koliada

The article is devoted to the issue of adaptation under the conditions of inclusive education of children with disabilities in a unified educational space, which is an irreversible process at the present stage of the development of society and its humanistic values. It is established that the realization of these conditions requires breaking down some stereotypes and mastering new forms of work by all participants of the educational process.  It is revealed that the education of children with disabilities in the conditions of mass secondary educational institutions is an acute problem for the Ukrainian state, which is experiencing the stage of becoming an insufficient perception of pedagogical innovation not only by parents but also by the teachers themselves. The education of children with needs of physical and mental development correction is based on the principles of balanced pedagogy, focused on the needs of children, which requires a certain level of staffing of specialists of a special profile, means, and conditions for providing psychological and pedagogical assistance.  It is emphasized that inclusive education is useful for children with special educational needs (with disabilities) as well as for children with typical development, family members and society as a whole. It is established that the practice of "involving" children with disabilities should be an integral part of national plans to achieve education for all without restrictions, and the organization of conditions for the adaptation of children with disabilities – an integral part of the pedagogical strategy and, undoubtedly, a new social and economic policy. It is argued that this requires a pivotal reform of secondary schools.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1465
Author(s):  
José Luiz P. R. Jivago ◽  
Juliana Lis Mendes Brito ◽  
Gustavo Capistrano ◽  
Marcus Vinícius-Araújo ◽  
Ediron Lima Verde ◽  
...  

Controlling populations of free-roaming dogs and cats poses a huge challenge worldwide. Non-surgical neutering strategies for male animals have been long pursued, but the implementation of the procedures developed has remained limited to date. As submitting the testes to high temperatures impairs spermatogenesis, the present study investigated localized application of magnetic nanoparticle hyperthermia (MNH) to the testicles as a potential non-surgical sterilization method for animals. An intratesticular injection of a magnetic fluid composed of manganese-ferrite nanoparticles functionalized with citrate was administered followed by testicle exposure to an alternate magnetic field to generate localized heat. Testicular MNH was highly effective, causing progressive seminiferous tubule degeneration followed by substitution of the parenchyma with stromal tissue and gonadal atrophy, suggesting an irreversible process with few side effects to general animal health.


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