Anomalous Relaxation in Colloidal Systems

Anomalous Relaxation in Colloidal Systems
Author: Avinash Kumar
Publisher: Springer Nature
Total Pages: 135
Release: 2022-10-22
Genre: Science
ISBN: 3031132807

The thesis presents a systematic study of the Mpemba effect in a colloidal system with a micron-sized particle diffusing in a water bath. While the Mpemba effect, where a system’s thermal relaxation time is a non-monotonic function of the initial temperature, has been observed in water since Aristotle’s era, the underlying mechanism of the effect is still unknown. Recent studies indicate that the effect is not limited to water and has been studied both experimentally and numerically in a wide variety of systems. By carefully designing a double-well potential using feedback-based optical tweezers, the author demonstrates that an initially hot system can sometimes cool faster than an initially warm system. The author also presents the first observation in any system of another counterintuitive effect—the inverse Mpemba effect—where the colder of the two samples reaches the thermal equilibrium at a hot temperature first. The results for both the observations agree with theoretical predictions based on the Fokker-Planck equation. The experiments reveal that, for carefully chosen conditions, a strong version of both of the effects are observed where a system can relax to the bath temperature exponentially faster than under typical conditions.

Anomalous Relaxation in Colloidal Systems

Anomalous Relaxation in Colloidal Systems
Author: Avināśa Kumāra
Publisher:
Total Pages: 0
Release: 2022
Genre: Colloids
ISBN: 9788303113283

The thesis presents a systematic study of the Mpemba effect in a colloidal system with a micron-sized particle diffusing in a water bath. While the Mpemba effect, where a system's thermal relaxation time is a non-monotonic function of the initial temperature, has been observed in water since Aristotle's era, the underlying mechanism of the effect is still unknown. Recent studies indicate that the effect is not limited to water and has been studied both experimentally and numerically in a wide variety of systems. By carefully designing a double-well potential using feedback-based optical tweezers, the author demonstrates that an initially hot system can sometimes cool faster than an initially warm system. The author also presents the first observation in any system of another counterintuitive effect-the inverse Mpemba effect-where the colder of the two samples reaches the thermal equilibrium at a hot temperature first. The results for both the observations agree with theoretical predictions based on the Fokker-Planck equation. The experiments reveal that, for carefully chosen conditions, a strong version of both of the effects are observed where a system can relax to the bath temperature exponentially faster than under typical conditions.

Microgel Suspensions

Microgel Suspensions
Author: Alberto Fernandez-Nieves
Publisher: John Wiley & Sons
Total Pages: 475
Release: 2011-01-11
Genre: Science
ISBN: 3527633014

Providing a vital link between chemistry and physics on the nanoscale, this book offers concise coverage of the entire topic in five major sections, beginning with synthesis of microgel particles and continuing with their physical properties. The phase behavior and dynamics of resulting microgel suspensions feature in the third section, followed by their mechanical properties. It concludes with detailed accounts of numerous industrial, commercial and medical applications. Edited by David Weitz, Professor at Harvard and one of the world's pre-eminent experts in the field.

Fractals, Diffusion, and Relaxation in Disordered Complex Systems

Fractals, Diffusion, and Relaxation in Disordered Complex Systems
Author: Yuri P. Kalmykov
Publisher: John Wiley & Sons
Total Pages: 432
Release: 2006-07-18
Genre: Science
ISBN: 0471790257

Fractals, Diffusion, and Relaxation in Disordered Complex Systems is a special guest-edited, two-part volume of Advances in Chemical Physics that continues to report recent advances with significant, up-to-date chapters by internationally recognized researchers.

Fractals, Diffusion, and Relaxation in Disordered Complex Systems

Fractals, Diffusion, and Relaxation in Disordered Complex Systems
Author: Yuri P. Kalmykov
Publisher: John Wiley & Sons
Total Pages: 592
Release: 2006-07-21
Genre: Science
ISBN: 047003713X

Fractals, Diffusion and Relaxation in Disordered Complex Systems is a special guest-edited, two-part volume of Advances in Chemical Physics that continues to report recent advances with significant, up-to-date chapters by internationally recognized researchers.

Anomalous Transport

Anomalous Transport
Author: Rainer Klages
Publisher: John Wiley & Sons
Total Pages: 608
Release: 2008-09-08
Genre: Science
ISBN: 3527622985

This multi-author reference work provides a unique introduction to the currently emerging, highly interdisciplinary field of those transport processes that cannot be described by using standard methods of statistical mechanics. It comprehensively summarizes topics ranging from mathematical foundations of anomalous dynamics to the most recent experiments in this field. In so doing, this monograph extracts and emphasizes common principles and methods from many different disciplines while providing up-to-date coverage of this new field of research, considering such diverse applications as plasma physics, glassy material, cell science, and socio-economic aspects. The book will be of interest to both theorists and experimentalists in nonlinear dynamics, statistical physics and stochastic processes. It also forms an ideal starting point for graduate students moving into this area. 18 chapters written by internationally recognized experts in this field provide in-depth introductions to fundamental aspects of anomalous transport.

Fractional Kinetics in Solids

Fractional Kinetics in Solids
Author: Vladimir Vasilʹevich Uchaĭkin
Publisher: World Scientific
Total Pages: 274
Release: 2013
Genre: Mathematics
ISBN: 9814355429

The standard (Markovian) transport model based on the Boltzmann equation cannot describe some non-equilibrium processes called anomalous that take place in many disordered solids. Causes of anomality lie in non-uniformly scaled (fractal) spatial heterogeneities, in which particle trajectories take cluster form. Furthermore, particles can be located in some domains of small sizes (traps) for a long time. Estimations show that path length and waiting time distributions are often characterized by heavy tails of the power law type. This behavior allows the introduction of time and space derivatives of fractional orders. Distinction of path length distribution from exponential is interpreted as a consequence of media fractality, and analogous property of waiting time distribution as a presence of memory. In this book, a novel approach using equations with derivatives of fractional orders is applied to describe anomalous transport and relaxation in disordered semiconductors, dielectrics and quantum dot systems. A relationship between the self-similarity of transport, the Levy stable limiting distributions and the kinetic equations with fractional derivatives is established. It is shown that unlike the well-known Scher Montroll and Arkhipov Rudenko models, which are in a sense alternatives to the normal transport model, fractional differential equations provide a unified mathematical framework for describing normal and dispersive transport. The fractional differential formalism allows the equations of bipolar transport to be written down and transport in distributed dispersion systems to be described. The relationship between fractional transport equations and the generalized limit theorem reveals the probabilistic aspects of the phenomenon in which a dispersive to Gaussian transport transition occurs in a time-of-flight experiment as the applied voltage is decreased and/or the sample thickness increased. Recent experiments devoted to studies of transport in quantum dot arrays are discussed in the framework of dispersive transport models. The memory phenomena in systems under consideration are discussed in the analysis of fractional equations. It is shown that the approach based on the anomalous transport models and the fractional kinetic equations may be very useful in some problems that involve nano-sized systems. These are photon counting statistics of blinking single quantum dot fluorescence, relaxation of current in colloidal quantum dot arrays, and some others.

Relaxation and Diffusion in Complex Systems

Relaxation and Diffusion in Complex Systems
Author: K.L. Ngai
Publisher: Springer Science & Business Media
Total Pages: 853
Release: 2011-03-25
Genre: Science
ISBN: 1441976493

The usefulness of the book to the reader is exposure to many different classes of materials and relaxation phenomena. They are tied together by the universal relaxation and diffusion properties they share, and a consistent explanation of their origin. The readers can apply what they learn to solve their own problems and use it as a stepping-stone to make further advances in theoretical understanding of the origin of the universality.